Bangkok, Thailand
Bangkok, Thailand

Chulalongkorn University , officially abbreviated as CU and commonly abbreviated as Chula , is the oldest university under the Thai modern educational system, founded in 1917 by King Vajiravudh who named it after his father, King Chulalongkorn . It is one of the best universities in Thailand and Southeast Asia according to several university rankings. It comprises nineteen faculties and institutes.Its campus occupies a vast area in downtown Bangkok. Diplomas were traditionally handed out at graduation by the King of Thailand, created and begun by King Prajadhipok . But at present, King Bhumibol Adulyadej delegates the role to one of his daughters, Princess Maha Chakri Sirindhorn. Wikipedia.

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Limkumnerd S.,Chulalongkorn University | Limkumnerd S.,Research Center in Thin Film Physics
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2017

The second law of thermodynamics, which asserts the non-negativity of the average total entropy production of a combined system and its environment, is a direct consequence of applying Jensen's inequality to a fluctuation relation. It is also possible, through this inequality, to determine an upper bound of the average total entropy production based on the entropies along the most extreme stochastic trajectories. In this work, we construct an upper bound inequality of the average of a convex function over a domain whose average is known. When applied to the various fluctuation relations, the upper bounds of the average total entropy production are established. Finally, by employing the result of Neri, Roldán, and Jülicher [Phys. Rev. X 7, 011019 (2017)]10.1103/PhysRevX.7.011019, we are able to show that the average total entropy production is bounded only by the total entropy production supremum, and vice versa, for a general nonequilibrium stationary system. © 2017 American Physical Society.

Sirikingkaew S.,Chulalongkorn University | Supakata N.,Chulalongkorn University
Journal of Green Building | Year: 2017

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture’s physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard. © 2017 by College Publishing. All rights reserved.

Keawsawasvong S.,Chulalongkorn University | Ukritchon B.,Chulalongkorn University
Computers and Geotechnics | Year: 2017

Finite element limit analysis was employed to determine the upper and lower bound solutions of the active failure of a planar trapdoor in non-homogeneous clays that have a linear increase of strength with depth. Influences of cover ratio, dimensionless strength gradient and trapdoor roughness on predicted failure mechanisms and stability factors were determined. In all cases, the exact stability factors were accurately bracketed by computed bound solutions within 1%. Accurate closed-form equations to predict the exact estimates of stability factors, trapdoor pressure and factor of safety using the new proposed factors for the cohesion and strength gradient are presented. © 2016 Elsevier Ltd

Sivaramakrishnan R.,Chulalongkorn University | Incharoensakdi A.,Chulalongkorn University
Bioresource Technology | Year: 2017

The high potential UV mutagenized Scenedesmus sp. was obtained in which the cells had a higher biomass and lipid content than the wild type with an increase from 1.9 to 2.4 g/L and from 40 to 55% of dry cell weight respectively after 12 days. Oxidative stress imposed by H2O2 treatment decreased the biomass of both the wild type and the mutant. The H2O2 treated mutant when grown in BG11 medium showed an increase in biomass which was in contrast to a decreased biomass observed in the H2O2 treated wild type. A 3-fold increase in lipid yield of 1.63 g/L was obtained in the oxidative stress-induced mutant compared to the wild type. Overall results indicate that prior treatment of UV-mutagenized Scenedesmus with oxidative stress can increase the total lipid production which, due to its derived methyl ester having acceptable biodiesel properties, can be potentially utilized for biodiesel production. © 2017 Elsevier Ltd

Srivorakul A.,Chulalongkorn University | Suwankawin S.,Chulalongkorn University
ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings | Year: 2016

In this paper, a novel high-frequency (HF) injection method of sensorless drive for doubly-fed induction machines (DFIM) is proposed. The high-frequency voltage is injected into the rotor winding and according to the concept of synchro, the rotor position can be simply extracted from the phase difference among the stator current and the rotor current regardless of machine and grid parameters. In addition, the proposed scheme is robust against the disturbance of high-frequency stator voltage propagated from the grid. The vector phase-locked loop (PLL) technique is employed to calculate rotor position and rotor speed simultaneously and the global stability of the PLL is validated. The feasibility of the proposed concept is verified by the experimental results with 4-kW DFIM drive. © 2016 IEEE.

Hayter A.J.,University of Denver | Kiatsupaibul S.,Chulalongkorn University
Journal of Quality Technology | Year: 2014

A random sample from a two-parameter gamma distribution is considered, and it is shown how exact inferences can be obtained for properties of the distribution. Kolmogorov tests based on the empirical cumulative-distribution function of the data are inverted to construct an exact confidence set for the two parameters. This can be used, for example, to construct exact confidence bands for the cumulative-distribution function of the gamma distribution, which also provide simultaneous inferences on the quantiles of the distribution. The exact confidence set can also provide confidence intervals for the individual parameters and for other functions of the parameters, such as the mean of the distribution. The new methodology is computationally straightforward and examples of its implementation are provided. Comparisons are made with standard approximate inference procedures that rely on asymptotic properties of maximum-likelihood estimates of the parameters and with a Bayesian simulation approach. The methodology can also be used to test whether a data set can be modeled with a gamma distribution and to test whether independent data sets can be modeled with a common gamma distribution.

Leela-apiradee W.,Chulalongkorn University | Lodwick W.A.,University of Colorado at Denver | Thipwiwatpotjana P.,Chulalongkorn University
Information Sciences | Year: 2017

We study six types of solutions (weak, strong, tolerance, control, Left-localized, and Right-localized solutions) to a two-sided interval system of max-plus linear equations with the same vector of variables on both sides of the equations and obtain their corresponding solvability conditions. These conditions are in the form of two-sided systems of max-plus linear inequalities which can be derived as a union of a number of interval inclusion linear systems. Therefore, we could work on the interval inclusion linear systems, instead of directly solving these six types of solutions themselves. An optimization problem with the two-sided interval system of max-plus linear constraints may be solved using the convexity of each solution set of the interval inclusion linear systems. © 2017 Elsevier Inc.

Kokkaew N.,Walailak University | Rudjanakanoknad J.,Chulalongkorn University
KSCE Journal of Civil Engineering | Year: 2017

Infrastructure investment is considered to be one of the crucial factors for promoting economic growth. In developing countries such as Thailand, government spending on economic infrastructure is critically important. However, promoting economic growth through infrastructure spending is not without consequences. For instance, a significant amount of carbon emissions was released by the construction and operation of roads in recent years. The aim of this paper is therefore to present a new model of green growth assessment for highway infrastructure that combines economic index with environmental performance of the project. Unlike its contemporary methods, the proposed Green Growth Index (GGI) accounts for the fact that the actual performance of a road project, both economic and environmental ones, may be different from what had been predicted. Accordingly, it may be of use to periodically evaluate the performance of the project in terms of its economic benefits and environmental impacts. A hypothetical road project is first used as a numerical example to illustrate how the proposed method can be applied. Then, a real highway project called Kanchanaphisek Road is then employed as a case study project presented in this paper. © 2017 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg

Chankrajang T.,Chulalongkorn University | Muttarak R.,International Institute For Applied Systems Analysis
Ecological Economics | Year: 2017

We investigate whether there are green returns to education, where formal education encourages pro-environmental behaviours using nationally representative surveys on environmental issues in Thailand. To establish the causal relationship between education and green behaviours, we exploit the instrumental variables strategy using the supply of state primary schooling i.e. the corresponding number of teachers per 1000 children, which varies over time and across regions as the instrument, while controlling for regional, cohort and income effects. We find that more years of schooling lead to a greater probability of taking knowledge-based environmentally-friendly actions a great deal, but not cost-saving pro-environmental actions. In addition, the paper finds no significant impact of formal education on concern about global warming nor the willingness to pay for environmental tax. © 2016 Elsevier B.V.

Sakthong P.,Chulalongkorn University | Munpan W.,Phramongkutklao Hospital
Applied Health Economics and Health Policy | Year: 2017

Purpose: Little was known about the head-to-head comparison of psychometric properties between SF-6D and EQ-5D-5L or the different value sets of EQ-5D-5L. Therefore, this study set out to compare the psychometric properties including agreement, convergent, and known-group validity between the SF-6D and the EQ-5D-5L using the real value sets from Thailand and the UK in patients with chronic diseases. Methods: 356 adults taking a medication for at least 3 months were identified from a university hospital in Bangkok, Thailand, between July 2014 and March 2015. Agreement was assessed by intraclass correlation coefficients (ICCs) and Bland–Altman plots. Convergent validity was evaluated using Spearman’s rank correlation coefficients between SF-6D and EQ-5D-5L and EQ-VAS and SF-12v2. For known-groups validity, the Mann–Whitney U test and Kruskal–Wallis test were used to examine the associations between SF-6D and EQ-5D-5L and patient characteristics. Results: Agreements between the SF-6D and the EQ-5D-5L using Thai and UK value sets were fair, with ICCs of 0.45 and 0.49, respectively. Bland-Altman plots showed that the majority of the SF-6D index scores were lower than the EQ-5D-5L index scores. Both the EQ-5D-5L value sets were more related to the EQ-VAS and physical health, while the SF-6D was more associated with mental health. Both EQ-5D-5L value sets were more sensitive than the SF-6D in discriminating patients with different levels of more known groups except for adverse drug reactions. Conclusions: The SF-6D and both EQ-5D-5L value sets appeared to be valid but sensitive to different outcomes in Thai patients with chronic diseases. © 2017 Springer International Publishing Switzerland

Khusakunrat P.,Chulalongkorn University | Sriratanaban J.,Chulalongkorn University
Asian Biomedicine | Year: 2017

Background: Evidence for the impact of health care spending in the area of maternal, newborn and child health (MCH) in developing countries is limited. Objectives: To examine the investment and medical care expenses for MCH under Universal Health Coverage (UHC) in Thailand. Methods: A prevention-appraisal-failure (PAF) cost element method was applied. Using a payer perspective, data related to PAF elements of MCH were collected from the Universal Coverage Scheme (UCS) inpatient claim database, UCS liability claims, the health-budget administration and health resource databases of the Ministry of Public Health, and the population census of The National Statistical Office in fiscal years 2007-2011. The main outcome measures included payments and budgets for MCH at a provincial level. Results: Investment and medical care costs of antenatal care to prevent and manage complications increased from US$7.77 per person per year (PPPY) in 2007 to US$11.69 PPPY in 2011. The payments to support qualityfocused activities ranged from US$0.60 to US$1.19 PPPY, whereas failure costs resulting from postpartum complications and UHC liability claims were US$1.92, 2.24, 2.35, 2.48, and 2.56 PPPY. Univariate regression analyses of year-on-year changes in prevention and appraisal costs for providing MCH and changes in the failure costs showed significant negative associations between 3 of 4 pairs of years Conclusions: Increased year-on-year costs of preventing MCH problems were associated with a reduction in year-on-year costs incurred for correcting problems. Despite increasing trends for all the costs, this finding indicated improvements in allocation of resources to address MCH challenges in Thailand.

Pitakchatwong C.,Chulalongkorn University | Chirachanchai S.,Chulalongkorn University
ACS Applied Materials and Interfaces | Year: 2017

Magnetic polymeric nanoparticles can be used for selective binding in a magnetic field. However, as the magnetic nanoparticles (MAG) are stabilized with polymers, the separation of the MAG from the polymer chains after use is difficult. This work proposes a combination of a thermoresponsive polymer with MAG allows for the as-desired simple removal of MAG from the polymer chains. For this, chitosan (CS) was conjugated with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and antibody (Ab) together with the physisorbed MAG as a thermo-magneto dual functional material. The key synthesis steps are (i) radical polymerization of NIPAM in the presence of mercaptoacetic acid so that the PNIPAM obtained contains terminal carboxylic acid groups (PNIPAM-COOH), (ii) the CS-N-hydroxysuccinamide water-based system that allows conjugation of CS with PNIPAM-COOH in water at room temperature, and (iii) the weak interaction between MAG and the CS chain. As a model application, CS is conjugated with the antirecombinant Leptospirosis Ab (rLipL32) to allow the selective binding and collection of the target antigen under the dual functions. This is the first demonstration of a simple but effective solution for MAG exclusion from the target molecules and will be practical for diverse applications, such as diagnosis, sensors, filtration, etc. © 2017 American Chemical Society.

Tan-a-Ram S.,Chulalongkorn University | Benjapolakul W.,Chulalongkorn University
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences | Year: 2017

In this paper, we propose to use a strategy for the two-user Gaussian X channel with limited receiver cooperation in the general case consisting of two parts: 1) the transmission scheme where the superposition coding is used and 2) the cooperative protocol where the two-round strategy based on quantize-map-and-forward (QMF) is employed. We image that a Gaussian X channel can be considered as a superposition of two Gaussian interference channels based on grouping of the sent messages from each transmitter to the corresponding receivers. Finally, we give an achievable rate region for the general case of this channel. © 2017 The Institute of Electronics, Information and Communication Engineers.

Chareonsiriwat L.,Chulalongkorn University | Chavasiri W.,Chulalongkorn University
Synthetic Communications | Year: 2017

Chromium-pillared montmorillonite (Cr-PLM) could be synthesized and efficiently utilized for styrene oxide transformations. The target aldehyde product could be quantitatively achieved from the isomerization of styrene oxide by using 10 wt% of Cr-PLM under reflux temperature for 15 min. The acetonide product could be achieved in excellent yield from the reaction of styrene oxide and acetone by using 10 wt% of Cr-PLM under room temperature for 20 min. The catalyst could be recovered and reused at least five times without loss of activity. © 2017 Taylor & Francis.

Srakaew V.,Chandrakasem Rajabhat University | Tachaboonyakiat W.,Chulalongkorn University
Journal of Molecular Structure | Year: 2017

Two parthenolide derivatives (PDs) were synthesized by chemical modification of parthenolide with concentrated hydrochloric acid and to evaluate their cytotoxicity to Hep-G2 cells in terms of their active functional groups and polarity. The chemical structures of the PDs were characterized by Fourier transform infrared, nuclear magnetic resonance and high resolution mass spectroscopy. Two PDs (PD1 and PD2) were fractionated by silica gel column chromatography with a Rf of 0.37 and 0.19, respectively, in a 1:1 (v/v) hexane: ethyl acetate mobile phase, indicating that PD1 was less polar than PD2. Compared to the parent parthenolide, both PD1 and PD2 had lost the active carbon-carbon double bond and epoxide functional groups, but retained the active 14-methyl and α-methylene-γ-butyrolactone groups. Although PD1 and PD2 possessed similar functional groups, they differed in their structural arrangement and consequentially their polarity. PD1 and PD2 exhibited an in vitro IC50 against the Hep-G2 cell line of 41.0 and 94.0 μg/ml, respectively, which was weaker than that for parthenolide (<1 μg/ml). Thus, the ranked polarity of PD2 > PD1 > parthenolide was inversely related to their cytotoxicity against the Hep-G2 cell line (parthenolide > PD1 > PD2). The obtained PDs may be potential novel anticancer substances. © 2017 Elsevier B.V.

Khlaisang J.,Chulalongkorn University | Songkram N.,Chulalongkorn University
Technology, Knowledge and Learning | Year: 2017

The proliferation of digital media now allows for learning to take place anywhere and anytime. The use of mobile devices and 3D virtual classrooms provides an integrated environment for effective learning. This study aims to examine the necessary factors for developing an effective virtual learning environment (VLE) system and to examine the effectiveness of the VLE system developed to enhance the range of twenty-first century skills of higher education students in the Association of Southeast Asian Nations (ASEAN) community. As a part of this study, four hundred higher education instructors completed questionnaires which were analyzed statistically using Exploratory Factor Analysis to determine the core factors which were then incorporated into the development of a VLE system. The system was tested on a sample of 90 volunteer undergraduate students from 5 ASEAN member countries. Data analysis using dependent t test indicated that there was a statistical difference between pre and post self-assessment scores of the twenty-first century skills in learning and innovation at the 0.05 level of significance. The finding and result were consistent with and could be supported by the results of behavior and trace observations and project assignments. In this paper, the 7 elements of the VLE system and 7 steps involved in its development are discussed, in addition to proposals for further implementation. © 2017 Springer Science+Business Media Dordrecht

Sangpongchai S.,Chulalongkorn University | Prueksasit T.,Chulalongkorn University
EnvironmentAsia | Year: 2017

This study aimed to find the optimum condition to prepare activated charcoal from spent coffee ground and to examine the adsorption efficiency of the BTEX released from water and oil base paints. The optimum condition was found to be carbonization at 400oC for 1 h, followed by activation with H3PO4 at a 1:1 (w/w) impregnation ratio and then carbonizedat 700oC for 1 h. This condition gave the highest iodine number (300.6 ± 5.1 mg/g), Brunaeur-Emmett-Teller (BET) surface area (1,769 m2/g), pore width (0.7947 nm) and pore volume (0.7517 cm3/g). The efficiency of the activated charcoal to adsorb the benzene and toluene emitted from normal and low volatile organic compounds water base paints was 99.8% and 99.7%, respectively. Furthermore, the adsorption efficiency of the activated charcoal from spent coffee ground (96.99 ± 0.54%) to remove the total BTEX released from oil base paints was higher than that achieved with the charcoal without chemical activation (66.97 ± 2.11%) or without carbonization (51.83 ± 10.32%). The produced activated charcoal from spent coffee ground by chemical activation was suitable for use as an adsorbent of the BTEX released from water and oil base paints. © 2017, Thai Society of Higher Eduation Institutes on Environment. All Rights Reserved.

Phuntusil N.,Chulalongkorn University | Limpiyakorn Y.,Chulalongkorn University
Lecture Notes in Electrical Engineering | Year: 2017

Over the past few years, many people have been concerned about declines in organic reach for their Facebook Pages. This has been a pain for many businesses, especially those small businesses and startup. Organic reach refers to how many people you can reach for free on Facebook by posting to your page. The declined organic reach results from some key changes to improve how News Feed chooses content. News Feed is aimed at becoming more engaging, even as the amount of content being shared on Facebook continues to grow. This paper presents a technique to increase Facebook organic reach. The method investigates some promising factors to predict the engaging content posting on business Pages, so that the post would gain exposure in News Feed of the liking users on Facebook. The proposed approach provides the alternative for businesses to increase the organic reach without more expense on advertising posted on Facebook Pages. © Springer Nature Singapore Pte Ltd. 2017.

Maneeintr K.,Chulalongkorn University | Charinpanitkul T.,Chulalongkorn University
Materials Science Forum | Year: 2017

Nowadays, the problems of climate change and global warming become more serious on environmental concern due to the higher amount of carbon dioxide in the atmosphere. Basically the main sources of carbon dioxide come from anthropogenic activities such as power generation, industries and so on. Currently, the effective technology to remove CO2 from these sources is absorption especially chemical absorption. Also, the chemicals used are one of the key parameters for effective CO2 removal. The widely used amine solutions are monoethanolamine (MEA) and diethanolamine (DEA). Nevertheless, they also have disadvantages such as low capacity, corrosion and high heat of regeneration thus making carbon capture technology more expensive. Therefore, many novel materials have been developed to improve the efficiency and compensate the disadvantages of some amines. Consequently, the objective of this work is to investigate the vapor-liquid equilibrium of CO2 in novel materials of 2-(methylamino)ethanol or 2-MAE and 3-Amino-1-Propanol or 3-AP at the temperature from 40 °C to 80 °C and CO2 partial pressures ranging from 5 to 100 kPa. The solubility results of CO2 in novel materials are compared with those of aqueous solution of MEA and DEA. For cyclic capacity, the results present that novel materials provide higher performance than that of MEA with less cost. This means that novel materials can save more energy and cost for solution regeneration and making it more economically viable. © 2017 Trans Tech Publications, Switzerland.

Wipatkrut P.,Chulalongkorn University | Poompradub S.,Chulalongkorn University
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2017

High conductivity reduced graphite oxide (RGO) was prepared by exfoliation of graphite waste from the metal smelting industry. To improve the surface properties of the RGO, the graphite oxide obtained based on Hummers’ method was reduced by L-ascorbic acid to give RGOV, which was then subjected to thermal reduction to obtain RGOT. The residual oxygen-containing groups in RGOV were almost completely removed by the thermal reduction and the conjugated graphene networks were restored in RGOT. The effect of the RGOT content in natural rubber (NR) on the cure, electrical and mechanical properties of the NR-RGOT (NG) composites was evaluated. The electrical conductivity of NR was increased by the inclusion of RGOT at a percolation threshold of 5 phr, with an electrical conductivity of 8.71 × 10−6 S/m. The mechanical properties, i.e., the modulus, tensile strength and hardness, of NG were comparable with those of conductive carbon black filled NR ones. © 2017 Elsevier B.V.

Karndumri P.,Chulalongkorn University
European Physical Journal C | Year: 2017

We holographically study supersymmetric deformations of N= 3 and N= 1 superconformal field theories in three dimensions using four-dimensional N= 4 gauged supergravity coupled to three-vector multiplets with non-semisimple SO(3 ) ⋉ (T3, T^ 3) gauge group. This gauged supergravity can be obtained from a truncation of 11-dimensional supergravity on a tri-Sasakian manifold and admits both N= 1 , 3 supersymmetric and stable non-supersymmetric AdS4 critical points. We analyze the BPS equations for SO(3) singlet scalars in detail and study possible supersymmetric solutions. A number of RG flows to non-conformal field theories and half-supersymmetric domain walls are found, and many of them can be given analytically. Apart from these “flat” domain walls, we also consider AdS3-sliced domain wall solutions describing two-dimensional conformal defects with N= (1 , 0 ) supersymmetry within the dual N= 1 field theory while this type of solutions does not exist in the N= 3 case. © 2017, The Author(s).

Chutima P.,Chulalongkorn University | Yothaboriban N.,Chulalongkorn University
International Journal of Industrial and Systems Engineering | Year: 2017

Parallel assembly lines (PALs) typify a production facility comprising of two or more straight assembly lines arranged in parallel to assemble similar products or different models of the same product. The configuration of PALs poses new challenges for the optimal design of the lines since the efficacy of the assembly system can be improved by combining stations of adjacent lines when balancing them. As a consequence, the multi-objective mixed-model parallel assembly line balancing problem is addressed in this paper. The hierarchical objectives to be optimised include: 1) minimising number of workstations; 2) minimising number of stations; 3) simultaneously minimising workload variation and maximising work-relatedness. The fuzzy BBO (F-BBO) algorithm is developed to tackle this problem and its performances are evaluated against several well-known algorithms under different instances of benchmark problems. The experimental results show that the solution quality of the proposed F-BBO is significantly better than the contestant algorithms. © 2017 Inderscience Enterprises Ltd.

Chuaicham C.,Chulalongkorn University | Maneeintr K.,Chulalongkorn University
Materials Science Forum | Year: 2017

To enhance oil recovery, surfactant flooding is one of the techniques used to reduce the interfacial tension (IFT) between displacing and displaced phases in order to maximize productivity. Due to high salinity of crude oil in the North of Thailand, surfactant flooding is a suitable choice to perform enhanced oil recovery. The objective of this work is to measure the IFT and observe the effects of parameters such as pressure, temperature, concentration and salinity on IFT reduction. In this study, sodium dodecylbenzenesulfonate is used as surfactant to reduce IFT. The results show that the major factor affecting reduction of IFT is surfactant concentration accounting for 98.1%. IFT reduces with the increase of salinity up to 86.3% and up to 9.6% for temperature. However, pressure has less effect on IFT reduction. The results of this work can apply to increase oil production in the oilfield in the North of Thailand. © 2017 Trans Tech Publications, Switzerland.

Srithongouthai S.,Chulalongkorn University | Tada K.,Kagawa University
Aquaculture | Year: 2017

The environmental impacts of a yellowtail (Seriola quinqueradiata) culture on sediment and water qualities were investigated at an intensive cage farm located in a coastal ecosystem (Shido Bay, the Seto Inland Sea, Japan) during low and high feeding times. The experimental design involved the establishment of surrounding sites (10 m from the cages) and a transect extending away from the cage at 0, 10, 50, and 100 m. The organic matter depositions were measured using sediment traps. Surface sediments and bottom water characteristics were also described. The organic depositions of the yellowtail cage farm in Shido Bay on the sediment were quite significant compared to the control site (100 m from the cage) and extended to 10 m around the fish farms. Due to the high organic deposition under the cage, the surface sediment showed an elevated level of organic-enriched sediments, and led to an increase in the production of sulfides. Oxygen depletion of the bottom water was accompanied by organic-enriched sediments and production of high-acid volatile sulfide (AVS) contents in the surface sediments, and caused a significant increase in ammonium (NH4 +) and phosphate (PO4 3 −) concentrations in the bottom water. As a result, impacts of organic waste from a yellowtail cage on surface sediments and bottom water quality were clearly found in Shido Bay. Statement of relevance Present study, the organic waste impacts of a yellowtail (Seriola quinqueradiata) culture on sediment and water qualities were investigated at an intensive cage farm located in a coastal ecosystem (Shido Bay, the Seto Inland Sea, Japan) during low and high feeding times. The results indicated that dramatic impacts of organic waste from a yellowtail cage on surface sediments and bottom water differences in Shido Bay. © 2017 Elsevier B.V.

Boonyasuwat S.,Chulalongkorn University | Tscheikuna J.,Chulalongkorn University
Fuel | Year: 2017

The effect of the presence of palm fatty acid distillate (PFAD) during co-processing with light gas oil (LGO) in hydrodesulfurization unit has been carried out in a near adiabatic, pilot-scale, and fixed-bed hydrotreating reactor, over commercial CoMo/Al2O3 under 280–350 °C, 25 barg, H2/feed ratio of 630 Nm3/m3 and 0.75 h−1. The amount of PFAD 5, 8, 12, and 25 wt% of PFAD in LGO was the feed mixtures. High conversion range on both desulfurization and deoxygenation reactions were achieved by every fraction of PFAD. The hydrocarbon products contained sulfur lower than 50 ppmw and neutralization number lower than 0.1 mg KOH/g. These products can be claimed as EURO 4 diesel following EN 590. The presence of PFAD in LGO improved the cetane index of the liquid products while lowered the product density. Highly heat effect was observed by an increasing of the reactor temperature up to 62 °C at the reactor outlet in the case of 25 wt% of PFAD. The increasing of the reactor temperature was resulting from an increasing amount of PFAD in LGO. The higher amount of PFAD slightly facilitated deoxygenation reaction, but impeded hydrodesulfurization reaction. The temperature rise also increased hydrocracking reaction evidenced by the lower contribution of total n-paraffin to the product mixture at higher PFAD in LGO. Finally, the hydrogen consumption was observed as linearly increased with an increasing amount of PFAD. The consumption was then theoretically calculated and extrapolated for hydrotreating of pure PFAD at 300 and 344 Nm3/m3, respectively. An additional hydrogen consumption of 44 Nm3/m3 was studied and discussed. © 2017 Elsevier Ltd

Gatemala H.,Chulalongkorn University | Ekgasit S.,Chulalongkorn University | Wongravee K.,Chulalongkorn University
Chemosphere | Year: 2017

A simple, rapid, and environmentally friendly process using hydrogen peroxide, was developed for recovering high purity silver directly from industry and laboratory wastes. Silver ammine complex, [Ag(NH3)2]+Cl−, derived from AgCl were generated and then directly reduced using H2O2 to reliably turn into high purity microcrystalline silver (99.99%) examined by EDS and XRD. Morphology of the recovered silver microcrystals could be selectively tuned by an addition of poly(vinyl pyrrolidone). The main parameters in the recovering process including pH, concentration of Ag+ and the mole ratio of H2O2:Ag+ were carefully optimized though the central composite design (CCD). The optimized condition was employed for a trial recovery of 50 L silver ammine complex prepared from a collection of silver-wastes during 3-year research on industrial nanoparticle production. The recovered silver microcrystals >700 g could be recovered with 91.27%. The remaining solution after filtering of the recovered silver microcrystals can be used repeatedly (at least 8 cycles) without losing recovery efficiency. Matrix interferences including Pb2+ and Cl− play a minimal role in our silver recovery process. Furthermore, the direct usage of the recovered silver microcrystals was demonstrated by using as a raw material of silver clay for creating a set of wearable silver jewelries. © 2017 Elsevier Ltd

Triukose S.,Chulalongkorn University | Rabinovich M.,Case Western Reserve University
Proceedings - 4th IEEE Workshop on Hot Topics in Web Systems and Technologies, HotWeb 2016 | Year: 2016

Content delivery networks (CDNs) carry a large portion of today's web traffic. Any improvement in their performance would have a direct impact on Internet users' experience. We propose a client-centric approach to improve the content delivery performance of CDNs with minimal alteration of the current CDN platform. A preliminary evaluation of our approach based on traffic traces from a large organization network shows significant promise, with around 22%-36% performance improvement for HTTP object downloads. © 2016 IEEE.

With recent insight into the development of dietary supplements and functional foods, search of effective phytochemical compounds and their mechanisms involved in prevention and management of diabetes and its complications are now being assessed. Cinnamic acid and its derivatives occur naturally in high levels of plant-based foods. Among various biological activities, cinnamic acid and its derivatives are associated with a beneficial influence on diabetes and its complications. The aim of the review is to summarize the potential mechanisms of these compounds for prevention and management of diabetes and its complications. Based on several in vitro studies and animal models, cinnamic acid and its derivatives act on different mechanism of actions, including stimulation of insulin secretion, improvement of pancreatic β-cell functionality, inhibition of hepatic gluconeogenesis, enhanced glucose uptake, increased insulin signaling pathway, delay of carbohydrate digestion and glucose absorption, and inhibition of protein glycation and insulin fibrillation. However, due to the limited intestinal absorption being a result of low bioavailability of cinnamic acid and its derivatives, current improvement efforts with entrapping into solid and liquid particles are highlighted. Further human clinical studies are needed to clarify the effects of cinnamic acid and its derivatives in diabetic patients. © 2017 by the author; licensee MDPI, Basel, Switzerland.

Promchat A.,Chulalongkorn University | Rashatasakhon P.,Chulalongkorn University | Sukwattanasinitt M.,Chulalongkorn University
Journal of Hazardous Materials | Year: 2017

A highly sensitive fluorescent turn-on cyanide probe is developed based on benzylidenes containing methylindolium group. Three benzylidene derivatives were synthesized from the condensations of three benzaldehyde derivatives and methyleneindoline. Only one of these three derivatives shows strong blue fluorescent response selectively to CN− which can be clearly observed in submicromolar range as the result of the cyanide addition to the indolium group. The detection of cyanide with this compound is optimized in aqueous media using non-ionic surfactant and sonication method to give very low limit of detection in subnanomolar range. The probe is also developed into a paper-based and gel-based sensing kits that can readily detect cyanide ion in micromolar range by naked eye under a common black light (360 nm) illumination. © 2017 Elsevier B.V.

Bodhisane S.,Chulalongkorn University | Pongpanich S.,Chulalongkorn University
British Journal of Health Care Management | Year: 2017

This study aims to analyse the progress of a community based health insurance (CBHI) scheme over a three-year period by comparing the results of this study to an earlier study. The data collection was implemented at the identical study sites to be comparable to the previous study outcome. Two logistic regression models were included in the study. One model aims to assess the accessibility of hospitalisation; whereas the other aims to assess the financial protection against catastrophic expenditure of using health services. All independent variables were derived from the Andersen behavioural model. It was found that the scheme has made good progress in fulfilling its initial objectives. The existence of a CBHI scheme is capable of enhancing accessibility to health services and providing financial protection against excessive expenditure. © MA Healthcare Ltd.

Damrongsiri S.,Chulalongkorn University
Journal of Environmental Management | Year: 2017

Demolition waste consisting of cement paste, lightweight concrete and bricks is a worthless material generated by a growing city. However, research suggests that it may be applied as an alternative heavy metal immobilising agent. The diverse characteristics of demolition waste were examined. Cadmium was selected as there presentative heavy metal to investigate demolition waste adsorption capacity. The solid-liquid distribution coefficients (Kd) were observed. The adsorption isotherms were applied to investigate adsorption characteristics. Carbon content in the demolition waste materials was low and mainly in inorganic form. Cement paste and lightweight concrete had an alkaline pH with very high acid neutralising capacity (ANC). The surface area and cation exchange capacity (CEC) of these materials were low. Cement paste possessed the highest pH, ANC, CEC and surface area, with the highest Kd; however, its specific surface area and CEC were low compared to activated carbon and organic material. The adsorption isotherms indicated surface heterogeneity with favourable conditions for adsorption and the mean free energy suggested physisorption with multilayer formation. The Kd values of the tested materials were comparable to soil which was not effective in immobilising heavy metal via adsorption mechanisms. However, the high pH and ANC of cement paste and lightweight concrete can improve the heavy metal adsorption capacity of soil and soil ANC that help prevents and controls leaching by heavy metals. © 2017 Elsevier Ltd

Napavichayanun S.,Chulalongkorn University | Aramwit P.,Chulalongkorn University
Journal of Biomaterials Science, Polymer Edition | Year: 2017

Wound healing is a natural process of body reaction to repair itself after injury. Nonetheless, many internal and external factors such as aging, comorbidity, stress, smoking, alcohol drinking, infections, malnutrition, or wound environment significantly affect the quality and speed of wound healing. The unsuitable conditions may delay wound healing process and cause chronic wound or scar formation. Therefore, many researches have attempted to search for agents that can accelerate wound healing with safety and biocompatibility to human body. Widely studied wound healing agents are those derived from either natural sources including plants and animals or chemical synthesis. The natural products seem to be safer and more biocompatible to human tissue. This review paper demonstrated various kinds of the animal-derived products including chitosan, collagen, honey, anabolic steroids, silk sericin, peptides, and proteoglycan in term of mechanisms of action, advantages, and disadvantages when applied as wound healing accelerator. The benefits of these animal-derived products are wound healing promotion, anti-inflammatory, antimicrobial activity, moisturizing effect, biocompatibility, and safety. However, the drawbacks such as allergy, low stability, batch-to-batch variability, and high extraction and purification costs could not be avoided in some products. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Prapagdee S.,Chulalongkorn University | Tawinteung N.,King Mongkut's University of Technology Thonburi
Environmental Science and Pollution Research | Year: 2017

Biochar is the carbonized material produced from biomass and is used in several environmental applications. The biochar characteristics depend on the carbonization conditions and feedstock. The suitability of a given biochar for soil improvement depends on the biochar characteristics, soil properties, and target plants. Biochar has been applied at 1–20% (w/w) in the soil, but currently there is a lack of information on what type and concentration of biochar are most suitable for a specific plant and soil quality. Too much biochar will reduce plant growth because of the high alkalinity of biochar, which will cause long-term soil alkalinity. In contrast, too little biochar might be insufficient to enhance plant productivity. In this study, a suitable concentration of cassava stem (an abundant agricultural waste in Thailand) biochar produced at 350 °C was evaluated for green bean (Vigna radiata L.) growth from germination to seed production in pots over 8 weeks. The soil fertility was increased with increasing biochar concentration. At 5% (w/w) biochar, the soil fertility and plant growth were significantly enhanced, while 10% (w/w) biochar significantly enhanced bean growth and bean pod production. The increased biochar concentration in the soil significantly increased the soil total nitrogen and extractable potassium (K) levels but did not affect the amount of available phosphorous. Biochar at 10% (w/w) significantly induced the accumulation of K in the stems, leaves, nut shells, and roots but not in nut seeds. Moreover, biochar not only increased the K concentration in soil but also increased the plant nutrient use efficiency of K, which is important for plant growth. [Figure not available: see fulltext.] © 2017 Springer-Verlag Berlin Heidelberg

Chenrai P.,Chulalongkorn University | Huuse M.,University of Manchester
Marine and Petroleum Geology | Year: 2017

After the first discovery of seabed pockmarks in the 1960s and 1970s, many examples of both modern and ancient pockmarks have been reported from sedimentary basins around the world. The exact mechanisms and fluids involved in pockmark formation are still subject to debate with many studies inferring that pockmark formation is a direct indication of hydrocarbon expulsion. This study provides the first description of a buried Pliocene paleo-pockmark field in the offshore Taranaki Basin, New Zealand. The paleo-pockmarks are located approximately 1.2–1.3 km below the seabed and are well imaged by three-dimensional seismic data. Their spatial density and size increases towards the distal portions of the fan, and they vary in size between 45 and 580 m in diameter and 2–35 ms TWT. Pockmark size is inversely correlated with the fan thickness in the study area. Detailed analysis rules out any links with faulting, while the relationship with fan variations in the depositional thickness suggests porewater expulsion during overburden progradation as the most likely cause of the paleo-pockmarks. A model is proposed in which rapid sediment loading generated overpressure which was greatest on the proximal fan due to the lateral gradient in the sediment load imposed by clinoform progradation. Fluids were consequently forced towards the distal fan where, eventually, the pore pressure exceeded the fracture gradient of the seal. The implications of this study are that not all pockmarks can be used as evidence for hydrocarbon expulsion in frontier regions and care should be taken to examine the subsurface context, plumbing systems and any associated acoustic anomalies before concluding on the pockmark origin. © 2017 Elsevier Ltd

Thisyakorn U.,Chulalongkorn University
Paediatrics and International Child Health | Year: 2017

In 1988, the generalised HIV/AIDS epidemic in Thailand began and in the same year the first HIV-exposed infant in Thailand was born at King Chulalongkorn Memorial Hospital, Bangkok. From the early to mid-1990s, an epidemic wave of HIV-infected women and infants occurred. Heterosexual HIV transmission, as described in the Asian Epidemic Model, was the major mode of spread in Thailand, causing an increasing number of HIV-infected pregnant women. The early and concerted multi-sectoral response of Thai society reduced the prevalence of HIV infection in pregnant women from 2% in the mid-1990s to 0.6% in 2015 and mother-to-child transmission of HIV (MTCT) from an estimated 20–40% to 1.9%. Thus, Thailand became the first Asian country to achieve the World Health Organization’s (WHO) targets for the elimination of MTCT. In this narrative review, the key historic evolutions of the science and policy of prevention of mother-to-child transmission of HIV (PMTCT) in Thailand that addressed the four prongs of the recommended WHO PMTCT strategy are described, and the lessons learned are discussed. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Kiatkittipong K.,King Mongkut's University of Technology Thonburi | Assabumrungrat S.,Chulalongkorn University
Journal of Cleaner Production | Year: 2017

The performances of sodium titanate nanotubes (Na-TT), hydrogen titanate nanotubes (H-TT), sodium titanate nanoribbons (Na-TR) and hydrogen titanate nanoribbons (H-TR) on adsorption, photodegradation of methylene blue (MB) and sedimentability were investigated. The intrinsic property of Na-TT with high hydroxyl groups (anionic) provided a strong electrostatic interaction between the MB (cationic) under dark condition. The equilibrium and kinetic adsorption were fitted with Langmuir isotherm models and the pseudo-second-order model, respectively. That is, Na-TT showed the best maximum adsorption capacity of 178.6 mg/g and adsorption kinetics of 0.119 g/mg·min. When the light is turned on, H-TT showed advance its photocatalytic reaction rate of 1.16 × 10−2 min−1 compared with Na-TT (the reaction rate of 1.02 × 10−2 min−1). This attributed the saturated MB adsorption on Na-TT obstructed capacity to absorb photons, and thus the reaction gradually occurred. For the separation of photocatalysts from the suspension by adding alum as coagulant, Na-TT afforded the best sedimentability of which remaining Na-TT in water was approximately 5%. This study demonstrates that adsorption, degradation and sedimentability were governed by the surface area and crystal structure, which revealed increasing the performance in the order TiO2 < H-TR < Na-TR < H-TT < Na-TT. © 2017 Elsevier Ltd

Ratanawaraha A.,Chulalongkorn University | Chalermpong S.,Chulalongkorn University
Transportation Research Record | Year: 2016

This study examined how the poor traveled to work in Bangkok, Thailand. Two sets of travel surveys were conducted in groups categorized as low income: residents in low-income communities and low-paid workers in various job locations. The results confirmed the general understanding that travel behaviors of the poor depended not only on income but also on public transport availability, job location, and home community location. Suburban residents with limited public transport services tended to travel by private motorcycles and to spend a large portion of household transport expenditures on vehicle and fuel costs. Others who lived near public transport services depended more on public transport and spent a larger share of transport expenditures on fares. No significant difference in household transport expenditures between the two groups was found. The travel survey by occupation revealed that privately owned motorcycles were the most popular mode, followed by employer-provided transport and public buses. Informal modes constituted a small share because of the relatively high fares. The average commute costs of informal modes were higher than the average cost of public buses and were closer to the average cost of private motorcycles. Male commuters were more dependent on private motorcycles and less on public transport than female commuters. With age, dependence on private motorcycles increased and dependence on public transport decreased. Average commute times did not vary significantly among occupational groups. These results highlighted the importance of low-cost public transport to vulnerable subgroups of the urban poor. © 2017, American Association for the Advancement of Science. All rights reserved.

Lertnuwat B.,Chulalongkorn University
International Journal of Applied Engineering Research | Year: 2016

The objective of this work is to numerically investigate how a shape of an air Taylor bubble in a stagnant liquid changes when the surface tension of the interface between gas and liquid is varied. Five examined surface tensions are chosen between 6 and 10 N/m so that all the flows around a Taylor bubble are entirely laminar. The Taylor bubble shape is adjusted until a proper shape is found by considering a pressure distribution of the air inside the bubble. This is obtained from a program code, developed from the implicit pressure-correction method on the finite volume framework with second order spatial accuracy. Simulation results finally show that the Taylor bubble shape will be slenderer if the surface tension is smaller because of the influence of the surface tension on Froude number. Additionally, it is also found that all the Taylor bubble shapes in this work are slenderer than that created by Dumitrescu’s model. © Research India Publications.

Ukritchon B.,Chulalongkorn University | Yingchaloenkitkhajorn K.,Rajamangala University of Technology at Srivijaya | Keawsawasvong S.,Chulalongkorn University
Computers and Geotechnics | Year: 2017

The undrained tunnel face stability in clay with a linearly increasing shear strength with depth was investigated by three-dimensional finite element analysis. Three parametric studies were performed to study the effects of the cover depth ratio, overburden stress factor and linear strength gradient ratio on the load factor of the undrained tunnel face stability. The influence of the linear strength gradient ratio on the predicted failure mechanism of the undrained face stability was discussed and examined. An approximate closed-form solution was proposed for three-dimensional undrained tunnel face stability in clays with constant or linearly increasing shear strength profiles with depth. © 2017 Elsevier Ltd

Srivannaboon S.,Chulalongkorn University | Munkongsujarit S.,National Science and Technology Development Agency
PICMET 2016 - Portland International Conference on Management of Engineering and Technology: Technology Management For Social Innovation, Proceedings | Year: 2016

Managing open innovation is typically viewed as managing a project with a set of expectations. It requires careful planning and proven management principles to enable companies to respond to their needs in the most effective and efficient way possible. However, the literature on integration and comparison among project management, project portfolio management and open innovation principles is limited. Viewing open innovations as a series of separate projects can lead to many problems including those related to transaction costs and risks. This paper extensively reviews the literature of project management, project portfolio management, and open innovation in the hope that these principles can be better integrated and synergized both in terms of the literature and in practice. © 2016 Portland International Conference on Management of Engineering and Technology, Inc.

Chancharoen R.,Chulalongkorn University | Maneeratana K.,Chulalongkorn University
Proceedings of 2016 IEEE International Conference on Teaching, Assessment and Learning for Engineering, TALE 2016 | Year: 2016

This paper described how a quick prototype project was re-organized in the Mechanics of Machinery, which had been a compulsory course for third-year mechanical engineering students. Each student group chose a configuration from the internet so that they would see good examples with no available analyses from textbooks. Then, students had to knowledge from class to analyze the mechanism kinematics, prepare data and resources for the construction, manufacture customized parts and assemble components into prototypes. From available manufacturing methods, most students chose the digital manufacturing, namely the laser cut and 3D printing. The ability to display and describe the prototypes were also evaluated. The instructional development was largely based on the CDIO Standards for design-build experiences and engineering workspace. The project was a success with configurations that were more complicated and realistic than previous years with fun and cool atmosphere. The major points for improvement was the documentation. Students' reflection showed that they could identify the activities and weakness which could be better conducted. The new workspace was reasonably received as the project space with the Net Promoter Score of 14% and 78.6% agreed or strongly agreed that they could link the project to the class contents. © 2016 IEEE.

Boonyagars L.,Bangkok University | Hirunwiwatkul P.,Chulalongkorn University | Hurst C.P.,Chulalongkorn University
International Journal of Tuberculosis and Lung Disease | Year: 2017

OBJ E CTIVE S : Tuberculosis (TB) is a major cause of morbidity and mortality in human immunodeficiency virus (HIV) infected patients. However, anti-tuberculosis drugs can cause cutaneous adverse drug reactions (CADRs). This study was conducted to evaluate differences in CADR incidence between low and high CD4 cell count in patients with low and high CD4 cell count and to identify other risk factors for CADR in HIV-TB co-infected patients. DESIGN: In a retrospective cohort of adult HIV-TB coinfected patients receiving standard anti-tuberculosis treatment between January 2008 and December 2015 at Vajira Hospital, Bangkok, Thailand, baseline demographic, clinical characteristics and factors associated with CADRs, including CD4 cell count status, were collected. RESULT S : Of 307 patients enrolled, CADRs occurred in 48 during the 6-month period of anti-tuberculosis treatment (incidence rate 0.41 events/person-year). Maculopapular rash was the most prevalent CADR. Low CD4 cell count was not associated with CADRs. Cox regression analysis revealed that moderate decrease in the glomerular filtration rate, history of drug hypersensitivity and concomitant cotrimoxazole use were all associated with CADRs. Concomitant antiretroviral therapy usewas associatedwith lower risk of CADRs.No difference in the time to CADRs between patients with lower and higher CD4 cell count could be demonstrated. CONCLUS ION: CADRs are common in HIV-TB coinfected patients. Early recognition and prompt withdrawal of the offending agent can prevent complications and improve TB care. © 2017 The Union.

Pongsachareonnont P.,Chulalongkorn University | Honglertnapakul W.,Chulalongkorn University | Chatsuwan T.,Chulalongkorn University
BMC Infectious Diseases | Year: 2017

Background: Identification of bacterial pathogens in endophthalmitis is important to inform antibiotic selection and treatment decisions. Hemoculture bottles and polymerase chain reaction (PCR) analysis have been proposed to offer good detection sensitivity. This study compared the sensitivity and accuracy of a blood culture system, a PCR approach, and conventional culture methods for identification of causative bacteria in cases of acute endophthalmitis. Methods: Twenty-nine patients with a diagnosis of presumed acute bacterial endophthalmitis who underwent vitreous specimen collection at King Chulalongkorn Memorial Hospital were enrolled in this study. Forty-one specimens were collected. Each specimen was divided into three parts, and each part was analyzed using one of three microbial identification techniques: conventional plate culture, blood culture, and polymerase chain reaction and sequencing. The results of the three methods were then compared. Results: Bacteria were identified in 15 of the 41 specimens (36.5%). Five (12.2%) specimens were positive by conventional culture methods, 11 (26.8%) were positive by hemoculture, and 11 (26.8%) were positive by PCR. Cohen's kappa analysis revealed p-values for conventional methods vs. hemoculture, conventional methods vs. PCR, and hemoculture vs. PCR of 0.057, 0.33, and 0.009, respectively. Higher detection rates of Enterococcus faecalis were observed for hemoculture and PCR than for conventional methods. Conclusions: Blood culture bottles and PCR detection may facilitate bacterial identification in cases of presumed acute endophthalmitis. These techniques should be used in addition to conventional plate culture methods because they provide a greater degree of sensitivity than conventional plate culture alone for the detection of specific microorganisms such as E. faecalis. Trial registration: Thai Clinical Trial Register No. TCTR20110000024. © 2017 The Author(s).

Bhupornvivat N.,Chulalongkorn University | Phupong V.,Chulalongkorn University
Asia Pacific Journal of Clinical Nutrition | Year: 2017

Background and Objectives: Pregnancy complications hypothesized to be related to vitamin D include preeclampsia, gestational diabetes, low birth weight, preterm delivery, Cesarean section and infectious disease. There have been a few studies which have demonstrated maternal serum vitamin D to be associated with preterm labor. The objective was to evaluate the serum vitamin D concentrations in Thai pregnant women with and without preterm labor and to find the prevalence of vitamin D deficiency and insufficiency in both groups. Methods and Study Design: Blood samples were collected from pregnant women with and without preterm labor (matched for gestational age). Serum 25-hydroxyvitamin D (25-OHD) concentrations were measured by chemiluminescence method. Results: A total of 60 pregnant women were included into the study, 30 patients in the preterm labor group and another 30 patients in the control group. The serum 25-OHD concentration was 21.0 ± 7.5 ng/mL and the prevalence of vitamin D deficiency was 48.3% in total group of pregnant women. The serum 25- OHD concentrations were not different between the preterm labor and the control groups (20.9±8.4 vs 21.2±6.7 ng/mL, p = 0.91). The prevalence of vitamin D deficiency and insufficiency were not different between the preterm labor and the control groups (53.3% vs 43.3%, p = 0.44 and 83.3% vs 90%, p = 0.45, respectively). Conclusion: The serum 25-hydroxyvitamin D concentrations and the prevalence of vitamin D deficiency and insufficiency were not different between the preterm labor and the control groups. The serum 25-OHD could not predict preterm labor in this Thai population.

Hasatsri S.,Chulalongkorn University | Aramwit P.,Chulalongkorn University
Dermatologic Surgery | Year: 2017

BACKGROUND Traditional evaluation of wound healing is sometimes subjective. It is necessary to develop qualitative and quantitative methods to enable more efficient and accurate evaluation of wounds. Recently, new techniques have been introduced and the correspondence between these techniques and clinician judgment is critical. OBJECTIVE Some nontraditional techniques that analyze wound healing were reviewed, which include measurements of the wound area, tissue color, skin barrier function, skin humidity, and keratinocyte morphology. METHODS This review article is based on medical research that focuses on the evaluation of wound healing. RESULTS Software-based and advanced device-based techniques generally provide more accurate and precise results than traditional ones, such as the ruler-based technique. Measurement of tissue color can also help to identify the type of tissue. Evaluation of skin barrier function can assist clinicians to analyze functional restoration of skin, whereas skin humidity demonstrates the exudate production status of the wound. In addition, keratinocyte morphology in the wound bed indicates quality of wound healing and side effects of treatment. CONCLUSION There is no gold standard method for qualitative and quantitative evaluation of wound healing. It is important to understand the type of wound, sample size, results obtained, advantages, and limitations of each technique. © 2016 by the American Society for Dermatologic Surgery, Inc.

Pansuk W.,Chulalongkorn University | Daungwilailuk T.,Chulalongkorn University
Concrete - Innovation and Design: fib Symposium Proceedings | Year: 2015

Fire-damaged reinforced concrete structures cannot be effectively used as it was. In order to reuse damaged structures, many repairing or strengthening procedures might be performed on the fire-damaged concrete surfaces. Therefore, it is necessary to inspeel the degree of damage of surface before choosing any suitable repairing or strengthening methods. Reinforced concrete specimens using limestone aggregates with varied concrete covering from 10 to 30 mm were lired in a gas-fired furnace with only one exposed surface for 30, 60, 90 and 120 minutes following the standard lire curve. Several non-destructive testing methods were performed such as visual inspection, ultrasonic pulse velocity test and rebound hammer. Then, coring test was performed to conlrm the results. Also, the experimental results were comparing with the predicted results with an ultrasonic pulse velocity test. Finally, the pull-off test was performed on damaged surfaces to show the remaining strength at different depths of damaged concrete.

Akkarakittichoke N.,Chulalongkorn University | Janwantanakul P.,Chulalongkorn University
Safety and Health at Work | Year: 2017

Background: Low back pain (LBP) is a major problem for office workers. Individuals adopting poor postures during prolonged sitting have a considerably increased risk of experiencing LBP. This study aimed to investigate seat pressure distribution characteristics, i.e., average pressure, peak pressure ratio, frequency of postural shift, and body perceived discomfort (BPD), during 1 hour of sitting among office workers with and without chronic LBP. Methods: Forty-six participants (chronic LBP = 23, control = 23) typed a standardized text passage at a computer work station for an hour. A seat pressure mat device was used to collect the seat pressure distribution data. Body discomfort was assessed using the Body Perceived Discomfort scale. Results: Office workers with chronic LBP sat significantly more asymmetrically than their healthy counterparts. During 1-hour sitting, all workers appeared to assume slumped sitting postures after 20 minutes of sitting. Healthy workers had significantly more frequent postural shifts than chronic LBP workers during prolonged sitting. Conclusion: Different sitting characteristics between healthy and chronic LBP participants during 1 hour of sitting were found, including symmetry of sitting posture and frequency of postural shift. Further research should examine the roles of these sitting characteristics on the development of LBP. © 2017 The Authors.

Charoenwet S.,Suratpittaya School | Christensen A.,Chulalongkorn University
IMSCI 2016 - 10th International Multi-Conference on Society, Cybernetics and Informatics, Proceedings | Year: 2016

As the use of social networking sites and online collaborative tools increases, educators can utilize these technologies to improve student engagement in the virtual classrooms. Edmodo, an internet-based learning management system (LMS), offers a secure virtual classroom that can be moderated by an instructor. In this study Edmodo was used to create supportive learning by facilitating channels for students to communicate with the teacher and participate in class activities. The virtual class space provided students opportunity to share ideas, follow up with class assignments, and take quizzes. The main aim of this study was to investigate the effects of integrating this networking system regarding students' perception towards the learning platform. Self-regulated learning (SRL) behaviors of students along with their learning performances were also examined. Students were to sign up for Edmodo classroom and work with provided class activities. Learning materials were uploaded for students and pre- and post-test scores were collected and analyzed. Self-reported survey questionnaires about SRL and students' perceptions were administered at the end of the course. The statistical analysis revealed that learning activities provided on the LMS significantly improved self-regulated learning behaviors and learning performance of students, with a positive perception towards the online learning environment.

Piyarungsri K.,Chulalongkorn University | Pusoonthornthum R.,Chulalongkorn University
Journal of Feline Medicine and Surgery | Year: 2017

Objectives: Chronic kidney disease (CKD) is a significant disease in cats. Identifying risk and protective factors may help to prevent this significant disease. Methods: An age-matched case-control study was performed to determine the risk factors in cats with naturally occurring CKD. Twenty-nine clinically normal cats aged ⩾5 years and 101 cats with naturally occurring CKD were studied. Risk factors were determined by interviewing cat owners from the Small Animal Hospital, Faculty of Veterinary Science, Chulalongkorn University, and veterinary hospitals in the Bangkok Metropolitan area, through questionnaires completed between June 2004 and November 2014. Univariable and multivariable analyses were performed using two independent proportional test methods and logistic regression analysis with backward elimination. Results: Male sex (odd ratios [OR] 2.80, 95% confidence interval [CI] 1.02–8.87; P = 0.02), tap water (OR 3.43, 95% CI 1.08–11.45; P = 0.03) and an outdoor lifestyle (OR 3.77, 95% CI 1.03–17.99; P = 0.04) were associated with an increased risk for CKD. Commercial dry cat food (OR 0.06, 95% CI 0.02–0.17; P = 0.00), filtered water (OR 0.13, 95% CI 0.03–0.52; P = 0.01) and an indoor lifestyle (OR 0.28, 95% CI 0.07–0.98; P = 0.02) were associated with a decreased risk. Logistic regression analysis using backward elimination demonstrated that cats fed commercial dry cat food (OR 0.042, 95% CI 0.01–0.17; P = 0.00) had a decreased risk for CKD compared with cats on other types of diet. Conclusions and relevance: Multivariable analysis found only feeding commercial dry cat food to be significant, suggesting that commercial dry cat food may be a potential protective factor for CKD in cats. © 2016, © The Author(s) 2016.

Kiatsupaibul S.,Chulalongkorn University | J. Hayter A.,University of Denver | Liu W.,University of Southampton
Computational Statistics and Data Analysis | Year: 2017

Consider a set of independent random variables with specified distributions or a set of multivariate normal random variables with a product correlation structure. This paper shows how the distributions and moments of these random variables can be calculated conditional on a specified ranking of their values. This can be useful when the ordering of the variables can be determined without observing the actual values of the variables, as in ranked set sampling, for example. Thus, prior information on the distributions and moments from their individual specified distributions can be updated to provide improved posterior information using the known ranking. While these calculations ostensibly involve high dimensional integral expressions, it is shown how the previously developed general recursive integration methodology can be applied to this problem so that they can be evaluated in a straightforward manner as a series of one-dimensional or two-dimensional integral calculations. Furthermore, the proposed methodology possesses a self-correction mechanism in the computation that prevents any serious growth of the errors. Examples illustrate how different kinds of ranking information affect the distributions, expectations, variances, and covariances of the variables, and how they can be employed to solve a decision making problem. © 2016 Elsevier B.V.

Rattanatanyong P.,Chulalongkorn University
Asian Pacific journal of cancer prevention : APJCP | Year: 2016

BACKGROUND: Methylation of promoter 2 of the SHP1 gene is epithelial cell specific, with reported potential as a lymph node metastatic marker.OBJECTIVE: To demonstrate SHP1-P2 methylation-specific quantitative PCR effectiveness in detecting colorectal cancer (CRC) DNA in lymph nodes.MATERIALS AND METHODS: SHP1-P2 methylation levels were measured in lymph nodes of CRC patients and compared with pathological findings and patient prognosis.RESULTS: Lymph nodes of CRC metastatic patients without microscopically detectable cancer cells had higher SHP1-P2 methylation levels than lymph nodes of controls (<0.001). In addition, a higher SHP1-P2 methylation level was associated with a shorter duration until adverse disease events, metastasis, recurrence and death (r2 = 0.236 and p value = 0.048). Studying two cohorts of 74 CRC patients without microscopic lymph node metastases showed that only the cohort containing samples with high SHP1-P2 methylation levels had a significant hazard ratio of 3.8 (95%CI = 1.02 to 14.2).CONCLUSIONS: SHP1-P2 methylation PCR can detect CRC cancer DNA in lymph nodes even if cancer cells are not visible under a microscope, confirming applicability as a potential universal lymph node metastatic marker.

Phalakarn K.,Chulalongkorn University | Suppakitpaisarn V.,University of Tokyo
Proceedings - 2016 4th International Symposium on Computing and Networking, CANDAR 2016 | Year: 2016

This paper presents parallel scalar multiplication techniques for elliptic curve cryptography using q-based addition-subtraction k-chain which can also effectively resist side-channel attack. Many techniques have been discussed to improve scalar multiplication, for example, double-and-add, NAF, w-NAF, addition chain and addition-subtraction chain. However, these techniques cannot resist side-channel attack. Montgomery ladder, random w-NAF and uniform operation techniques are also widely used to prevent side-channel attack, but their operations are not efficient enough comparing to those with no side-channel attack prevention. We have found a new way to use k-chain for this purpose. In this paper, we extend the definition of k-chain to q-based addition-subtraction k-chain and modify an algorithm proposed by Jarvinen et al. to generate the q-based addition-subtraction k-chain. We show the upper and lower bounds of its length which lead to the computation time using the new chain techniques. The chain techniques are used to reduce the cost of scalar multiplication in parallel ways. Comparing to w-NAF, which is faster than double-and-add and Montgomery ladder technique, the maximum computation time of our q-based addition-subtraction k-chain techniques can have up to 25.92% less addition costs using only 3 parallel computing cores. We also discuss on the optimization for multiple operand point addition using hybrid-double multiplier which is proposed by Azarderakhsh and Reyhani-Masoleh. The proposed parallel chain techniques can also tolerate side-channel attack efficiently. © 2016 IEEE.

Likitdecharoj P.,Chulalongkorn University | Ratanavaraporn J.,Chulalongkorn University
BMEiCON 2016 - 9th Biomedical Engineering International Conference | Year: 2016

Gelatin is a protein derived from collagen by an acid treatment (type A gelatin, GA) or an alkaline treatment (type B gelatin, GB). In this study, GA and GB were chemically modified by introducing functional groups on their structures to obtain cationized (GE) and anioized gelatin derivatives (GS), respectively. Conjugation of ethylenediamine resulted in the higher positive charge and free amino group content of GE. Various gelatin derivatives GA, GB, GE and GS were fabricated into microspheres using water in oil emulsion and dehydrothermal crosslinking techniques. All gelatin microspheres had a round shape with average size around 40-50 μm in the dry state. In the swollen state, sizes of GA, GB, and GS microspheres were increased to 73-89 μm while that of GE microspheres was up to 150 μm. The highly hydrophilicity of strong positive charged GE may be attributed to its high swelling ability (swelling ratio ∼ 3.1) and solubility after immersed in water at 37°C for 24 h although it had high crosslinking degree. On the other hand, GA, GB, and GS had swelling ratio only 1.7-1.9 and less water-solubilized. These gelatin microspheres having different properties will be introduced as carrier for delivery of drug in which the release rate of drug can be controlled. This drug delivery system will be applied for the localized treatment of disease like osteoarthritis with minimal invasion. © 2016 IEEE.

Vichaphund S.,National Metal and Materials Technology Center | Sricharoenchaikul V.,Chulalongkorn University | Atong D.,National Metal and Materials Technology Center
Journal of Analytical and Applied Pyrolysis | Year: 2017

Lime mud, the industrial waste from pulp and paper mills, was used as a raw material for preparing calcium oxide (CaO)-based catalysts. Lime mud was heated at 1000. °C to transform it into active CaO and then modified by adding 5. wt% Fe or Ni (as nitrates) using the wet impregnation method and calcining to form the Fe/CaO and Ni/CaO catalysts. The fast pyrolysis of Jatropha residues to bio-oil with no catalyst and with the derived CaO, Fe/CaO and Ni/CaO catalysts was studied using an analytical pyrolysis-GC/MS at 500. °C at a biomass: catalyst ratio of 1:1 and 1:5. A Jatropha residue: catalyst ratio of 1:5 was more optimal for enhancing aliphatic hydrocarbon production and decreasing the amount of oxygenated and N-containing compounds. The presence of the CaO catalyst completely eliminated the undesirable acids and sugars in the bio-oil, significantly decreased N-containing compounds and considerably promoted the formation of aliphatic hydrocarbons up to 37.3%. The Fe/CaO and Ni/CaO catalysts further increased the selectivity for aliphatic hydrocarbons, and reduced aldehyde formation compared to with CaO, with Ni/CaO being the best catalyst for hydrocarbon selectivity (47.5%). Overall, these CaO-based catalysts derived from industrial lime mud waste can be used for catalytic fast pyrolysis applications. © 2017.

Kamonkhantikul K.,Chulalongkorn University | Arksornnukit M.,Chulalongkorn University | Takahashi H.,Tokyo Medical and Dental University
International Journal of Nanomedicine | Year: 2017

Background: Fungal infected denture, which is typically composed of polymethylmethacrylate (PMMA), is a common problem for a denture wearer, especially an elderly patient with limited manual dexterity. Therefore, increasing the antifungal effect of denture by incorporating surface modification nanoparticles into the PMMA, while retaining its mechanical properties, is of interest. Aim of the study: This study aimed to evaluate antifungal, optical, and mechanical properties of heat-cured PMMA incorporated with different amounts of zinc oxide nanoparticles (ZnOnps) with or without methacryloxypropyltrimethoxysilane modification. Materials and methods: Specimens made from heat-cured PMMA containing 1.25, 2.5, and 5% (w/w) nonsilanized (Nosi) or silanized (Si) ZnOnps were evaluated. Specimens without filler served as control. The fungal assay was performed placing a Candida albicans suspension on the PMMA surface for 2 h, then Sabouraud Dextrose Broth was added, and growth after 24 h was determined by counting colony forming units on agar plates. A spectrophotometer was used to measure the color in L* (brightness), a* (red-green), b* (yellow-blue) and opacity of the experimental groups. Flexural strength and flexural modulus were determined using a three-point bending test on universal testing machine after 37°C water storage for 48 h and 1 month. Results: The antifungal, optical, and mechanical properties of the PMMA incorporated with ZnOnps changed depending on the amount. With the same amount of ZnOnps, the silanized groups demonstrated a greater reduction in C. albicans compared with the Nosi groups. The color difference (∆E) and opacity of the Nosi groups were greater compared with the Si groups. The flexural strength of the Si groups, except for the 1.25% group, was significantly greater compared with the Nosi groups. Conclusion: PMMA incorporated with Si ZnOnps, particularly with 2.5% Si ZnOnps, had a greater antifungal effect, less color differences, and opacity compared with Nosi ZnOnps, while retaining its mechanical properties. © 2017 Kamonkhantikul et al.

Pailoplee S.,Chulalongkorn University
Open Geosciences | Year: 2017

Earthquake activities along the Sumatra-Andaman Subduction Zone (SASZ) were clarified using the derived frequency-magnitude distribution in terms of the (i) most probable maximum magnitudes, (ii) return periods and (iii) probabilities of earthquake occurrences. The northern segment of SASZ, along the western coast of Myanmar to southern Nicobar, was found to be capable of generating an earthquake of magnitude 6.1-6.4 Mw in the next 30-50 years, whilst the southern segment of offshore of the northwestern and western parts of Sumatra (defined as a high hazard region) had a short recurrence interval of 6-12 and 10-30 years for a 6.0 and 7.0 Mw magnitude earthquake, respectively, compared to the other regions. Throughout the area along the SASZ, there are 70- almost 100% probabilities of the earthquake with Mw up to 6.0 might be generated in the next 50 years whilst the northern segment had less than 50% chance of occurrence of a 7.0 Mw earthquake in the next 50 year. Although Rangoon was defined as the lowest hazard among the major city in the vicinity of SASZ, there is 90% chance of a 6.0 Mw earthquake in the next 50 years. Therefore, the effective mitigation plan of seismic hazard should be contributed. © 2017 Santi Pailoplee.

Kidyoo M.,Chulalongkorn University | Paliyavuth C.,Chulalongkorn University
Taiwania | Year: 2017

A new species, Ceropegia digitiformis Kidyoo, was discovered from northeastern Thailand. It is here described and illustrated. Photographs and a diagnostic comparison with the morphologically similar related species, Ceropegia thwaitesii Hook., are also provided. These two species display clear difference in shapes and pubescence of the corona lobes. © 2017, College of Life Science. All rights reserved.

Watthanaphanit A.,Mahidol University | Rujiravanit R.,Chulalongkorn University
International Journal of Biological Macromolecules | Year: 2017

Here, we aims to demonstrate a simple concept in biomaterials design by using natural resources solely as raw materials to fabricate elastic wound care dressing. Elasto-gel films comprise of silk sericin (SRC), natural rubber (NR), and chitin whisker (CTW) were developed. A glue-like protein SRC found in silk cocoons is beneficial for the treatment of wounds due to its superior skin moisturizing ability. However, the pure SRC film is generally difficult to be fabricated because of its weak structural feature. This limitation was overcome by using NR as a binder which consecutively rendered elasticity and strength of the films. CTW was chosen as another component to promote ability of the films for tissue restoration. Before the film formation, protein in the natural rubber latex (NRL) was removed to avoid allergic and cytotoxic problems. The enzyme-treated NR/SRC (ETNR/SRC) films having different blend compositions were fabricated by solution casting technique. The highest amount of the SRC to gain an easy to handle ETNR/SRC film was 30%. The ETNR/SRC/CTW films having 20% SRC were fabricated and studied in comparison. Essential properties of the films as elastic wound care dressings were investigated and effect of the materials chemistry on the observed properties were discussed. © 2017 Elsevier B.V.

Arunsawatwong S.,Chulalongkorn University | Kalvibool P.,Chulalongkorn University
IEEE Region 10 Annual International Conference, Proceedings/TENCON | Year: 2017

The waveforms of electric power generated from renewable energy sources can vary persistently in a random manner for a long period of time. This paper presents the design of load frequency controllers for power systems that are subject to persistent disturbances by using the principle of matching and the method of inequalities. In the design formulation, the generation rate constraint is explicitly taken into account and a battery energy storage system (BESS) is used. Moreover, a PI controller in the main loop and a lag/lead controller in the BESS minor loop are designed simultaneously so as to mitigate the effects of power fluctuation caused by normal load and renewable energy sources. The principal design objective is to guarantee that the peak magnitudes of frequency deviation, generation rate and BESS power output always stay strictly within respective bounds despite all possible disturbances. The numerical results clearly show that the framework adopted here is suitable for solving such a design problem. © 2016 IEEE.

Prakannoppakun N.,Chulalongkorn University | Sinthupinyo S.,Chulalongkorn University
Proceedings of the 8th International Conference on Electronics, Computers and Artificial Intelligence, ECAI 2016 | Year: 2016

Skill rating is one of major issues in the world of sport and even also in competitive games, which are being considered as a type of sport. However, to keep players engaged with the games, we have to match them against other player whose skill is close to theirs, the question is how can we rate skills of a player. We designed a novel method which is suitable for rating skill of players in Multiplayer online battle arena (MOBA). The MOBA is the one of many games in which groups of players randomly meet and play as a team to win the game. We hence propose a new method to measure the individual skill level from several key factors. We analyze factors team's performance and show that it is better than the standard method. © 2016 IEEE.

Na-Lampang N.,Chulalongkorn University | Vatanawood W.,Chulalongkorn University
Proceedings of the 8th International Conference on Electronics, Computers and Artificial Intelligence, ECAI 2016 | Year: 2016

This paper proposes an alternative of configuration management system development using IT ontology and semantic technology. To make the IT service management more effective especially the configuration management, the manager needs the appropriate and ad-hoc analysis for decision making. Our approach proposes a knowledge base to accompany the conventional database system in order to flexibly cope with the strategic problems. An ontology schema is designed to handle the configuration management of IT service resources in term of RDF N-Triple. The classes and hierarchy of the schema are provided along with the appropriate property relations among the configuration items. We design the queries by SWRL & SQWRL rules for IT service functions, such as how to allocate the budget for the annual maintenance fee, etc. The Protege software is used during our ontology schema design. We develop a Java web application with Jena Framework along with the Jena Fuseki ontology server to successfully demonstrate our ontology-based approach. © 2016 IEEE.

Chaemsiriwat P.,Chulalongkorn University | Wangjiraniran W.,Chulalongkorn University
Materials Science Forum | Year: 2017

This research study about the abatement cost of CO2 reduction by using fly ash as a clinker substitute in Thailand cement industry. And also present the sensitivity analysis about the factors that affect the abatement cost. The proportion of quantity to use fly ash as a clinker is equal to 1: 1 ton, therefor will calculate at 1 ton of clinker which make the quantity of mitigated CO2 in this research is equal to 0.825 tonCO2/year. Use the information in year 2015 to analyze, such as the exchange rate, fly ash price and transportation rate. And use average distance of fly ash transportation from the power plant to cement plant to calculate. From the information, the approach to reduce CO2 by this method is without additional investment. Because fly ash is small it can be mixed with clinker before grinding step of the original process. The CO2 abatement cost of this method is equal to -106.16 USD/tonCO2, which is regarded as a worthwhile investment. The factor is the most affect to mitigation cost is transportation rates. The transportation current rate is 0.092 USD/ton/km but if it increases, the abatement cost will also increase accordingly. Moreover we also calculate the maximum distance to decide on the purchase of fly ash from each of power plant. © 2017 Trans Tech Publications, Switzerland.

Sairatanathongkham W.,Chulalongkorn University | Wangjiraniran W.,Chulalongkorn University
Materials Science Forum | Year: 2017

The main objective of this article is to forecast CO2 mitigation from clinker production and to evaluate Fly Ash potential, used Clinker Substitution for CO2 mitigation in cement industry between years 2015-2036 in Thailand following information of the Thailand's power developments plan (PDP2015). PDP2015 forecasts the potential of fly ash in the year 2036 which is estimated at 3.94 M ton and 48.76 M TonCO2 of CO2 emission from 58.01 M Ton of clinker production process. The methodology which is used for potential evaluation of fly ash and amount of CO2 can evaluate from Mae Moh power plant technology. 1 MW can occur 952.3427 Ton and amount of CO2 emission from utilizing is 0.825 TonCO2/TonneCli which is a default value of CSI (Cement Sustainability Initiative).The three different scenarios are used to analysis in this study. The condition of Business As Usual (BAU) scenario is the need of technology, used in 2015 as a base case. The full potential scenario (FP) is represent to the 100% fly ash using. The final scenario is called Zoning scenario (Z scenario) which consists of price rate (270 THB per Ton) and transportation rate (6 THB per kilometer of fly ash). From the result, in 2036 fly ash occur 7.46 M Ton that can mitigate CO2 volume up to 6.15 M TonCO2. © 2017 Trans Tech Publications, Switzerland.

Chaiwongwatanakul S.,Chulalongkorn University
Asian Pacific journal of cancer prevention : APJCP | Year: 2016

Long interspersed elements-1s (LINE-1s) are dispersed all over the human genome. There is evidence that hypomethylation of LINE-1s and levels of sex steroids regulate gene expression leading to cancer development. Here, we compared mRNA levels of genes containing an intragenic LINE-1 in breast cancer cells treated with various sex steroids from Gene Expression Omnibus (GEO), with the gene expression database using chi-square analysis ( We evaluated whether sex steroids influence expression of genes containing an intragenic LINE-1. Three sex steroids at various concentrations, 1 and 10 nM estradiol (E2), 10 nM progesterone (PG) and 10 nM androgen (AN), were assessed. In breast cancer cells treated with 1 or 10 nM E2, a significant percentage of genes containing an intragenic LINE-1 were down-regulated. A highly significant percentage of E2-regulated genes containing an intragenic LINE-1 was down-regulated in cells treated with 1 nM E2 for 3 hours (<3.70E-25; OR=1.91; 95% CI=2.16-1.69). Similarly, high percentages of PG or AN- regulated genes containing an intragenic LINE-1 were also down-regulated in cells treated with 10 nM PG or 10 nM AN for 16 hr (p=9.53E-06; OR=1.65; 95% CI=2.06-1.32 and p=3.81E-14; OR=2.01; 95% CI=2.42-1.67). Interestingly, a significant percentage of AN-regulated genes containing an intragenic LINE-1 was up-regulated in cells treated with 10 nM AN for 16 hr (p=4.03E-02; OR=1.40; 95% CI=1.95-1.01). These findings suggest that intragenic LINE-1s may play roles in sex steroid mediated gene expression in breast cancer cells, which could have significant implications for the development and progression of sex steroid-dependent cancers.

Autthanit C.,Chulalongkorn University | Jongsomjit B.,Chulalongkorn University
Journal of Porous Materials | Year: 2017

In the present work, we report results of a comparative study of zirconium (Zr) and bimetal (Zr and La) containing in SBA-15 silica, which was prepared by conventional sol–gel and one-step hydrothermal methods. The structural and surface properties of all samples were characterized by low and high-angle XRD, nitrogen physisorption, FTIR, Raman, UV–Vis, SEM/EDX, TEM, and NH3-TPD techniques. The experimental results demonstrated that the samples obtained from the sol–gel method retain the two-dimensional hexagonal order structure of SBA-15. Compared to samples obtained from the hydrothermal method, the pore system lacking long-range order was observed. The incorporation of Zr and bimetal (Zr and La) had an effect on the textural properties of both synthesized SBA-15 samples. This modified SBA-15 mesoporous samples still exhibited high specific surface area, large pore volume and narrow pore size distribution. Surface acidity in the SBA-15 silica suggests new active sites, especially Brønsted acid type, indicating its future potential applications when acid sites are required. © 2017 Springer Science+Business Media New York

Velmurugan R.,Chulalongkorn University | Incharoensakdi A.,Chulalongkorn University
Biochemical Engineering Journal | Year: 2017

In the present study, a novel catalyst was prepared by combining cellulase enzyme complex with metal oxides as a substrate activating and enzyme stabilizing component. The cellulose content obtained from Chlorella sp. CYB2 was treated with magnetic metal oxide linked enzyme complex through xylan aldehyde linking molecule. In order to improve the hydrolysis process, MgO was blended with Fe3O4 and the resulting complex had significant improvement in immobilization yield, activity recovery and hydrolysis of cellulose. Addition of xylan aldehyde as a linking molecule enhanced the enzyme binding onto metal nanoparticle. The results on hydrolysis showed the reduction in crystallinity of cellulose corresponding to the increase in enzymatic digestibility of cellulose. Under optimized conditions, the glucose yield obtained was 91% of theoretical maximum. The enhancement in hydrolysis is correlated with the degradation of large molecule into well accessible substrate assisted by the action of metal oxides. © 2017 Elsevier B.V.

Lam Van D.,Chulalongkorn University | Boonyatee T.,Chulalongkorn University
International Journal of Geotechnical Engineering | Year: 2017

The unloading point method (ULM) is a simple technique for determining equivalent static load-settlement behaviour of piles from rapid load tests. Since the ULM assumes piles to be rigid, it does not consider the effects of elastic shortening and the lag in response along pile shaft. This assumption can be improved by increasing measurement points, e.g. adding an accelerometer at pile toe. In this article, the stress-wave theory was used instead of the additional sensor for estimating the response at pile toe. By considering the lag in response along pile shaft, a better estimate of the stationary point can be obtained and used in the ULM. The refined ULM was verified by comparing with the non-linear model using rapid load test results in literatures. Predictions by the proposed method agreed well with the results from static pile load tests and were better than other methods in this study. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Sukprasansap M.,Chulalongkorn University | Chanvorachote P.,Chulalongkorn University | Tencomnao T.,Chulalongkorn University
Food and Chemical Toxicology | Year: 2017

Oxidative and endoplasmic reticulum (ER) stresses cause neuronal damage leading to neurodegenerative disorders. Cleistocalyx nervosum var. paniala (CNP) berry fruit has been shown to possess powerful antioxidant properties. Here, we investigated the neuroprotective effect of CNP extract against glutamate-mediated oxidative/ER stress-induced cell death in mouse hippocampal neuronal HT22 cells. CNP extract was clarified for its radical scavenging activities, total phenolic and anthocyanin contents. The key anthocyanin cyanidin-3-glucoside was used as a marker to standardize the extract used in the study. We found that pretreated cells with CNP extract (0.05–1 μg/ml) prevented neuronal cell death in response to 5 mM glutamate evaluated by cell viability MTT, LDH and apoptosis/necrosis Annexin V/propidium iodide co-staining assays. For mechanistic approach, glutamate-induced cell death through reactive oxygen species (ROS)-mediated ER stress pathways, indicating the increase of ROS and ER stress signature molecules including calpain, caspases-12 and C/EBP homologous proteins (CHOP). CNP extract inhibited ROS production. Moreover, the extract also suppressed the specific-ER stress apoptotic proteins level in glutamate-induced cells by upregulating the gene expression of cellular antioxidant enzymes (SODs, CAT, GPx and GSTs). Taken together, our results provide information about and the molecular mechanism of CNP extract as a promising neuroprotectant and antioxidant. © 2017 Elsevier Ltd

Keawsawasvong S.,Chulalongkorn University | Ukritchon B.,Chulalongkorn University
Computers and Geotechnics | Year: 2017

New plasticity solutions for the undrained stability of unsupported conical excavations in homogeneous and non-homogeneous clays were solved by axisymmetric finite element limit analysis. Three parametric studies were performed on excavated height ratios, slope inclinations and dimensionless strength gradients. In all cases, the exact stability factors were accurately bracketed by computed bound solutions within 0.6%. An accurate closed-form equation of the stability factor was proposed from nonlinear regression analysis of lower bound solutions. New conical stability factors for soil cohesion, strength gradient, and coupling effect of these components were deduced to conveniently and accurately predict a safe solution in practice. © 2016 Elsevier Ltd

Phuluanglue A.,Chulalongkorn University | Khaodee W.,Mahanakorn University of Technology | Assabumrungrat S.,Chulalongkorn University
Computers and Chemical Engineering | Year: 2017

Intensified process of sorption enhanced chemical-looping reforming (SECLR) for hydrogen production was studied. This process was modified by recycling a portion of solid NiO and CaO from air reactor (AR) to reforming reactor (RR) and employing the exhaust CO2 as sweep gas at the calcination reactor (CR) under energy self-sufficient operation. By comparing the process performances among SECLR, conventional steam reforming (SR) and sorption enhanced steam reforming (SESR) at their optimum conditions, the intensified SECLR under adiabatic operation showed the best performance with hydrogen productivity of 3.95kmol/h, CH4 conversion of 98% and H2 purity of 98.37%. Additionally, the optimized SECLR process operated adiabatically required the solid ratio from CR to AR of 0.945 and solid ratio from AR to RR of 0.008, leading to the minimum of heat requirement. Furthermore, the influence of CO2 content in feed stream on adiabatic operation of the SECLR process was investigated. © 2017 Elsevier Ltd.

Tuntiwachiratrakun P.,Chulalongkorn University | Vateekul P.,Chulalongkorn University
2016 International Conference on Control, Automation and Information Sciences, ICCAIS 2016 | Year: 2016

Nowadays, classification tasks are very challenging because data is usually large and imbalanced. They can cause low prediction accuracy and high computation costs. Active Learning is a technique that employs only a small set of data to construct an initial classification model. Then, it iteratively improves the model by incrementally learning from the misclassified examples. In this paper, we aim to improve prediction accuracy by applying Active Learning. To solve the imbalance issue, the active model was iteratively updated based on the G-mean, and the under sampling sampling was also applied. The proposed algorithm was suitable for large scale data since it did not need to use the whole data set to construct a model. The experiment was conducted on two standard corpuses, one of which contained more than 100,000 examples. The result showed that a prediction performance of standard technique (Neural Network) can be improved by applying the Active Learning strategy for 5%-13%. Furthermore, this technique also outperformed other classical classification algorithms including K-nearest neighbors (kNN), Support Vector Machine (SVM), Decision Tree (DT), Naïve Bayes (NB) and Artificial Neural Network (ANN). © 2016 IEEE.

Pacaphol K.,Chulalongkorn University | Aht-Ong D.,Chulalongkorn University
Surface and Coatings Technology | Year: 2017

Nanocellulose is a natural polymer containing abundant hydroxyl groups which can create the network of hydrogen bonds between intra- and inter-molecular cellulose chains and also react with many other functional molecules. These interactions are helpful to film formation and surface modification. Silylation is a well-known modification, in which silane is substituted into a molecule for the improvement of desired properties such as hydrophobization, antimicrobial activity, and compatibilization with plastics for composites. However, to our knowledge, there is no study regarding the silane-modified nanocellulose for adhesion improvement even though nanocellulose film has potential for applications as a protective coating, insulation coating, biomedical coating, etc. Therefore, in this work nanofibrillated cellulose in aqueous suspension - obtained from hemp stubs - was used as a coating material. Various silanes containing dissimilar functional groups were employed in order to improve poor adhesion of nanocellulose films on glass and aluminum substrates and also enhance their physical and mechanical properties. It was found that silane containing an amino group provided the optimum increase of adhesion performance when compared with epoxy and methacryloxy groups, in which higher ratio of amino silane tended to give better adhesion on glass and aluminum substrates. Moreover, amino silane was capable of improving surface hardness, elastic modulus, and scratch resistance of coating film and also providing the satisfied results of optical properties and hydrophobic characteristic to nanocellulose film. © 2017 Elsevier B.V.

Chiasakul T.,Chulalongkorn University | Uaprasert N.,Chulalongkorn University
Journal of Clinical Laboratory Analysis | Year: 2017

Background: Diagnosis of thalassemia or hemoglobinopathy concomitant with iron deficiency anemia (IDA) is challenging. Method: We report a case of 43-year-old female whose diagnosis of compound heterozygosity for hemoglobin Constant Spring (HbCS) and Hb Paksé became apparent after the treatment of IDA. Results: Prior to treatment, Hb analysis using isoelectric focusing (IEF) showed HbA 95.6%, HbA2 2.7%, and HbCS 1.7% compatible with heterozygous HbCS. After 4 months of oral iron therapy resulting in an improved Hb level, her HbCS level was substantially increased to 8.7% on IEF suggesting homozygous HbCS. Subsequent DNA analysis using multiplex amplification refractory mutation system analysis revealed compound heterozygosity for HbCS and Hb Paksé. Conclusion: This case demonstrated that IDA can significantly reduce HbCS/Hb Paksé levels and probably mask the diagnosis of homozygous HbCS, homozygous Hb Paksé or the compound heterozygosity for both hemoglobinopathies by hemoblogin analysis. The test should be repeated after resolution of IDA, or molecular testing should be performed to confirm the diagnosis. © 2017 Wiley Periodicals, Inc.

Vedrasco E.,Chulalongkorn University | Lursinsap C.,Chulalongkorn University
ACM International Conference Proceeding Series | Year: 2016

This paper analyzes the current active Medical Tourism websites and discusses the availability of various features among these websites. The analysis is based on the collected data about the features' importance and users' online search patterns from people have experiences in Medical Tourism and medical information search on the Internet. This study focuses on the Medical Tourism market in Thailand due to its popularity and high ranking among other international Medical Tourism destinations. A Medical Tourism aggregative system is proposed by using one of the Data Mining tools-Association Rule. © 2016 ACM.

Leela-Apiradee W.,Chulalongkorn University | Thipwiwatpotjana P.,Chulalongkorn University
Annual Conference of the North American Fuzzy Information Processing Society - NAFIPS | Year: 2017

Product pricing is one of the most important strategies in doing any business. In this paper, we propose a specific marketing situation as an acceptable product pricing problem when the data on purchasing power and transportation cost cannot be measured exactly but can be shown as intervals of possible values. This problem is formulated as a minimization problem of a differentiable convex objective function with max-plus interval linear constraints A ⊗ x = b where x is called an L-localized solution. Its feasible region is nonconvex but could be viewed by the union of box constraints. The steepest descent algorithm is applied to optimize the objective function with respect to each of these box constraints and obtained an optimal solution from the best value. © 2016 IEEE.

Samutsri S.,Chulalongkorn University | Panpranot J.,Chulalongkorn University | Tungasmita D.N.,Chulalongkorn University
Microporous and Mesoporous Materials | Year: 2017

Propylsulfonic acid functionalized mesoporous cubic Ia-3d amorphous (MCA) silica (MCA-Pr-SO3H) was synthesized by co-condensation. Different amounts of ZSM-5 seeds were added into the Ia-3d mesopore silica gel to yield ZM-x composites (where x is the wt.% loading level of ZSM-5). The structure characterization, morphology and acidity of the synthesized materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and 13C-NMR techniques. The composite materials were found to have properties of both mesoporous (MCA) and ZSM-5, with the ZSM-5 loading level having a major effect on the structure of the Ia-3d mesoporous composite. The MCA-Pr-SO3H catalytic activity in the anisole alkylation reaction with tert-butanol was compared to that of Amberlyst-15, ZSM-5 and ZM-30 materials. The highest yield of total tert-butylated anisole (TBA) products was obtained with MCA-Pr-SO3H, with the major products being 4-tert-butyl anisole (4-TBA), 2-tert-butyl anisole and 2, 4-di-tert-butyl anisole. Compared with the other materials, ZM-30 promoted high selectivity of para-alkylated anisole (4-TBA) and the yield of TBA products. © 2016 Elsevier Inc.

Winskel H.,Southern Cross University of Australia | Perea M.,University of Valencia | Ratitamkul T.,Chulalongkorn University
Quarterly Journal of Experimental Psychology | Year: 2012

Previous research supports the view that initial letter position has a privileged role in comparison to internal letters for visual-word recognition in Roman script. The current study examines whether this is the case for Thai. Thai is an alphabetic script in which ordering of the letters does not necessarily correspond to the ordering of a word's phonemes. Furthermore, Thai does not normally have interword spaces. We examined whether the position of transposed letters (internal, e.g., porblem, vs. initial, e.g., rpoblem) within a word influences how readily those words are processed when interword spacing and demarcation of word boundaries (using alternatingbold text) is manipulated. The eye movements of 54 participants were recorded while they were reading sentences silently. There was no apparent difference in degree of disruption caused when reading initial and internal transposed-letter nonwords. These findings give support to the view that letter position encoding in Thai is relatively flexible and that actual identity of the letter is more critical than letter position. This flexible encoding strategy is in line with the characteristics of Thai-that is, the flexibility in the ordering of the letters and the lack of interword spaces, which creates a certain level of ambiguity in relation to the demarcation of word boundaries. These findings point to script-specific effects operating in letter encoding in visual-word recognition and reading. © 2012 Copyright The Experimental Psychology Society.

Theepharaksapan S.,Chulalongkorn University | Chiemchaisri C.,Kasetsart University | Chiemchaisri W.,Kasetsart University | Yamamoto K.,University of Tokyo
Bioresource Technology | Year: 2011

Removals of pollutants and toxic organic compounds and reduction in bio-toxicity of leachate along an operating full-scale leachate treatment system utilizing chemical coagulation, sand filtration, microfiltration (MF) and reverse osmosis (RO) membrane were evaluated. High pollutant removals were achieved mainly by coagulation and sand filtration. Major toxic organic pollutants, i.e. DEHP, DBP and bisphenol A were removed by 100%, 99.6% and 98.0%. Acute toxicity test using water flea, Nile Tilapia and common carp and genotoxicity (Comet assay) were conducted to determine toxicity reduction in leachate along the treatment. Ammonia was found to be the main acute toxic compounds in leachate as determined by LC50 but the effect of organic substances was also observed. DNA damage in fish exposed to diluted raw leachate (10% of LC50) was found to be 8.9-24.3% and it was subsequently decreased along the treatment. Correlation between pollutants and its bio-toxicity was established using multivariable analyses. © 2010 Elsevier Ltd.

Juntapram K.,Chulalongkorn University | Praphairaksit N.,Bangkok University | Siraleartmukul K.,Chulalongkorn University | Muangsin N.,Center for Petroleum
Carbohydrate Polymers | Year: 2012

Two mucoadhesive thiolated polymers were synthesized by the covalent attachment of homocysteine thiolactone (HT) to chitosan and N,N,N-trimethyl- chitosan (TM-chitosan) at various chitosan:HT ratios. The amount of thiol and disulphide groups immobilized on the chitosan influenced the polymer's mucoadhesion positively and negatively, respectively, with the optimal chitosan:HT (w/w) ratio being found to be 1:0.1. The interaction between mucin and chitosan and its three derivatives was highest for the thiolated chitosan derivatives but was pH dependent. HT-chitosan and TM-HT-chitosan, with the thiol groups of 64.15 and 32.48 μmol/g, respectively, displayed a 3.67- and 6.33-fold stronger mucoadhesive property compared to that of the unmodified chitosan at pH 1.2, but these differences were only ̃1.7-fold at pH 6.4. The swelling properties of TM-HT-chitosan and HT-chitosan were higher than that of chitosan and TM-chitosan, attaining a swelling ratio of up to 240% and 140%, respectively, at pH 1.2 within 2 h. © 2011 Elsevier Ltd.

Juntapram K.,Chulalongkorn University | Praphairaksit N.,Bangkok University | Siraleartmukul K.,Chulalongkorn University | Muangsin N.,Chulalongkorn University
Carbohydrate Polymers | Year: 2012

Novel hydrogel polyelectrolyte complexes (PECs) between the N,N,N,-trimethylchitosan-homocysteine thiolactone (TM-HT-chitosan) and two anionic polymers were investigated. The particles of pure thiolated chitosan and its PECs with alginate and carrageenan were fabricated using the electrospray ionization technique. The hydrogel PEC particles were characterized by scanning electron microscopy, dynamic light scattering, Fourier transform infrared microscopy, thermogravimetric analysis, encapsulation efficiency (EE), mucoadhesive property and in vitro drug release behavior. TM-HT-chitosan/ alginate particles could be loaded with camptothecin (CPT), employed as a model anti-cancer drug, at an over 70% EE, and revealed both a reduced burst effect and a prolonged release of CPT over 3 days. The resultant TM-HT-chitosan/ alginate PEC particles displayed a 5.60-, 1.86- and 1.55-fold stronger mucoadhesive property compared to that of the unmodified chitosan/alginate PEC at pH 1.2, 4.0 and 6.4, respectively, and this was not affected by the CPT loading level. © 2012 Elsevier Ltd. All rights reserved.

Riaz U.,Jamia Millia Islamia University | Nwaoha C.,Chulalongkorn University | Ashraf S.M.,Jamia Millia Islamia University
Progress in Organic Coatings | Year: 2014

Conducting polymer (CP) coatings have been extensively investigated for corrosion protection of iron, steel and other metals owing to their superior performance in highly aggressive environments and ecofriendly characteristics. Corrosion protective coatings based on CP nanocomposites have opened a new area of research for obtaining low cost coatings with enhanced performance and tailored properties. This mini review highlights the latest developments in the corrosion protective performance of CP composite coatings with natural resource derived polymers. The presence of nanoscale dispersion of CP as filler significantly improves the barrier properties and lifetime of the organic polymeric coatings. These lowcost nanocomposite coatings are expected to play an important role in combating corrosion which can lead to drastic improvement in corrosion protection. © 2014 Elsevier B.V. All rights reserved.

Dechrugsa S.,Chulalongkorn University | Kantachote D.,Prince of Songkla University | Chaiprapat S.,Prince of Songkla University
Bioresource Technology | Year: 2013

Biochemical methane potential (BMP) assay was conducted at 35°C to evaluate the effects of inoculum to substrate ratio (ISR) and substrate mix ratio between para-grass and pig manure co-digesting using different inocula. Rubber latex digester (RLD) inoculum showed higher methanogenic activity (41.4mL CH4/gVS) than pig farm digester (PFD) inoculum (37.3mL CH4/gVS). However, the maximum methane yields, occurred at the highest para-grass mix ratio (G), were 369.6, 437.6, 465.9 and 442.6mL CH4/gTSadded for RLD inoculum, versus 332.4, 475.0, 519.5 and 521.9mL/gTSadded for PFD inoculum at ISR 1, 2, 3, and 4, respectively. HPr, HBu and HVa appeared at higher G, corresponding to substrate's higher biodegradability. Response surface indicated that higher ISR and G had a significantly positive impact on methane yield. It suggested the use of higher ISR, i.e. 3 or 4, for BMP assay of these co-substrates. Dominant species of fermentative bacteria in each inoculum was tested by DGGE. © 2013 Elsevier Ltd.

Rimdusit S.,Chulalongkorn University | Tiptipakorn S.,Kasetsart University | Jubsilp C.,Srinakharinwirot University | Takeichi T.,Toyohashi University of Technology
Reactive and Functional Polymers | Year: 2013

Polybenzoxazine (PBZ), a novel class of high performance thermosetting phenolic resin, has been developed in order to overcome many shortcomings of conventional phenolic materials from either novolac or resole type resins. The paper first provides the overview of this high temperature material including main types, chemical structure of each type, and properties of the polymer, especially the synergistic behavior in thermal properties. It then describes the manufacturing technique to produce the monomeric resin as well as some applications of the polymer. © 2012 Elsevier Ltd. All rights reserved.

Rattanapan A.,Chulalongkorn University | Limtong S.,Kasetsart University | Phisalaphong M.,Chulalongkorn University
Applied Energy | Year: 2011

A thin-shell silk cocoon (TSC), a residual from the silk industry, is used as a support material for the immobilization of Saccharomyces cerevisiae M30 in ethanol fermentation because of its properties such as high mechanical strength, light weight, biocompatibility and high surface area. In batch fermentation with blackstrap molasses as the main fermentation substrate, an optimal ethanol concentration of 98.6g/L was obtained using a TSC-immobilized cell system at an initial reducing sugar concentration of 240g/L. The ethanol concentration produced by the immobilized cells was 11.5% higher than that produced by the free cells. Ethanol production in five-cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in a packed-bed reactor, a maximum ethanol productivity of 19.0g/(Lh) with an ethanol concentration of 52.8g/L was observed at a 0.36h-1 dilution rate. © 2011 Elsevier Ltd.

Wong W.P.,Universiti Sains Malaysia | Jaruphongsa W.,Chulalongkorn University | Lee L.H.,National University of Singapore
IEEE Transactions on Automatic Control | Year: 2011

We analyze how to allocate the budget for data collection effectively when data envelopment analysis (DEA) is used for predicting the efficiency. We formulate this problem under a Bayesian framework and propose two heuristics algorithms, i.e., a gradient-based algorithm and a hybrid GA algorithm to solve this optimization problem. Our results indicate that effective allocation of budget for data collection can greatly reduce the overall data collection effort in comparison with a uniform budget allocation. © 2006 IEEE.

Karndumri P.,Chulalongkorn University | O Colgain E.,University of Oviedo
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Recently, a general principle, called c-extremization, which determines the exact R symmetry of two-dimensional conformal field theories with N=(0,2) supersymmetry, was identified. In this work we show that the supergravity dual corresponds to the extremization of the T tensor of N=2 gauged supergravity in three dimensions. To support this claim, we demonstrate that the expected central charge of conformal field theories arising from twisted compactifications of four-dimensional N=4 Super-Yang-Mills on Riemann surfaces, whose gravity dual is a reduction of five-dimensional U(1) 3 gauged supergravity, is recovered in the three-dimensional framework. © 2013 American Physical Society.

Karndumri P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2014

Supersymmetric and non-supersymmetric deformations of large N = (4, 4) SCFT with superconformal symmetry D 1(2, 1; α) × D 1(2, 1; α) are explored in the gravity dual described by a Chern-Simons N = 8, (SO(4) × SO(4)) ⋉ T12 gauged supergravity in three dimensions. For α > 0, the gauged supergravity describes an effective theory of the maximal supergravity in nine dimensions on AdS 3 × S 3 × S 3 with the parameter α being the ratio of the two S 3 radii. We consider the scalar manifold of the supergravity theory of the form SO(8, 8)/SO(8) × SO(8) and find a number of stable non-supersymmetric AdS 3 critical points for some values of α. These correspond to non-supersymmetric IR fixed points of the UV N = (4, 4) SCFT dual to the maximally supersymmetric critical point. We study the associated RG flow solutions interpolating between these fixed points and the UV N = (4, 4) SCFT. Possible supersymmetric flows to non-conformal field theories and half-supersymmetric domain walls within this gauged supergravity are also investigated. © 2014 The Author(s).

Ariyaprakai S.,Assumption University | Limpachoti T.,Assumption University | Pradipasena P.,Chulalongkorn University
Food Hydrocolloids | Year: 2013

In this study, sucrose esters were presented as a promising alternative to petrochemically synthesized Tweens for application in coconut milk emulsions. The interfacial and emulsifier properties of sucrose ester (SE), mainly sucrose monostearate, had been investigated in comparison with Tween 60 (TW), an ethoxylate surfactant. The interfacial tension measurement showed that SE had a slightly better ability to lower the interfacial tension at coconut oil-water interface. These surfactants (0.25 wt%) were applied in coconut milk emulsions with 5 wt% fat content. The effects of changes in pH, salt concentration, and temperature on emulsion stability were analyzed from visual appearance, optical micrograph, droplet charges, particle size distributions, and creaming index. Oil droplets in both SE and TW coconut milk emulsions extensively flocculated at pH 4, or around the pI of the coconut proteins. Salt addition induced flocculation in both emulsions. The pH and salt dependence indicated polyelectrolyte nature of proteins, suggesting that the proteins on the surface of oil droplets were not completely displaced by either added nonionic SE or TW. TW coconut milk emulsions appeared to be thermally unstable with some coalesced oil drops after heating and some oil layers separated on top after freeze thawing. The change in temperature had much lesser influence on stability of SE coconut milk emulsions and, especially, it was found that SE emulsions were remarkably stable after the freeze thawing. © 2012 Elsevier Ltd.

Katanyoo K.,Bangkok University | Sanguanrungsirikul S.,Chulalongkorn University | Manusirivithaya S.,Bangkok University
Gynecologic Oncology | Year: 2012

Objective: To compare the treatment outcomes between squamous cell carcinoma (SCC) and adenocarcinoma (ACA) in locally advanced cervical cancer patients. Methods: All medical records of stages IIB-IVA of cervical cancer patients who had completed treatment between 1995 and 2008 were reviewed. ACA 1 case was matched for SCC 2 cases with clinical stage, tumor size, treatment modalities (radiation therapy (RT) vs concurrent chemoradiation (CCRT)). Treatment outcomes including response to RT/CCRT, time to complete response (CR), patterns of treatment failure and survival outcomes were analyzed. Results: A total of 423 patients with stages IIB-IVA (141 ACA: 282 SCC) were included. Most of the patients (about 60%) had stage IIB. The overall complete responses (CR) between ACA and SCC were 86.5% and 94.7%, respectively (p = 0.004). Median time to clinical CR from RT/CCRT of ACA were 2 months (0-5 months) compared with 1 month (0-4 months) for SCC (p = 0.001). Pelvic recurrence and distant failure were found in 2.1% and 14.9% in ACA, and corresponding with 3.9% and 15.6% in SCC. The 5-year overall survival rates of ACA compared to SCC were 59.9% and 61.7% (p = 0.191), respectively. When all prognostic factors are adjusted, clinical staging was the only factor that influenced overall survival. Conclusion: ACA in locally advanced cervical cancer had poorer response rate from treatment and also used longer time to achieve CR than SCC. However, these effects were not determinants of survival outcomes. © 2012 Elsevier Inc. All rights reserved.

Saramul S.,Chulalongkorn University | Ezer T.,Old Dominion University
Ocean Dynamics | Year: 2014

A high-resolution (∼1 km horizontal grid and 21 vertical layers) numerical model based on the Princeton Ocean Model (POM) has been used to study the 3D dynamics of the Upper Gulf of Thailand (UGOT). While influenced by tides and rivers like other estuarine systems, the UGOT is unique because it is wide (∼100 km∈×∈100 km), it is shallow (average depth of only ∼15 m), it is located in low latitudes (∼12.5°N-13.5°N), and it is influenced by the seasonal monsoon. Sensitivity studies were thus conducted to evaluate the impact that surface heat fluxes, monsoonal winds, river runoffs, and the low latitude may have on the dynamics; the latter has been evaluated by modifying the Coriolis parameter and comparing simulations representing low and mid latitudes. The circulation in the UGOT changes seasonally from counter-clockwise during the northeast monsoon (dry season) to clockwise during the southwest monsoon (wet season). River discharges generate coastal jets, whereas river plumes tend to be more symmetric near the river mouth and remain closer to the coast in low latitudes, compared with mid-latitude simulations. River plumes are also dispersed along the coast in different directions during different stages of the monsoonal winds. The model results are compared favorably with a simple wind-driven analytical estuarine model. Comparisons between an El Niño year (1998) and a La Niña year (2000) suggest that water temperatures, warmer by as much as 2 °C in 1998 relative to 2000, are largely driven by decrease cloudiness during the El Niño year. The developed model of the UGOT could be used in the future to address various environmental problems affecting the region. © 2014 Springer-Verlag Berlin Heidelberg.

Nwaoha C.,Chulalongkorn University | Wood D.A.,DWA Energy Ltd
Journal of Natural Gas Science and Engineering | Year: 2014

Natural gas is destined to become a larger part of Nigerian energy mix as the country seeks to guarantee the sustainability of its energy supply and benefit from greater energy efficiency and reduce energy-related costs. However, this continues to be a relatively slow process with large quantities of associated gas still being flared, as it has been since the 1950s. Natural gas' availability, versatility, accessibility, and more importantly its clean-burning characteristics when compared to other fossil fuels, is a substantial driver for its further utilisation in country. Nigeria is endowed with some 182 trillion cubic feet (tcf) of proven gas reserves, and that is mostly located in the Niger Delta. Nigeria's government is keen to develop local utilization of gas employing a range of available technologies. These technologies include gas to power using gas fed by transmission and distribution pipeline networks to supply combined cycle gas turbines (CCGT), compressed natural gas (CNG), gas to liquids (GTL) to supply transportation fuels, gas to fertilizer (GTF) and petrochemicals to support domestic industries, and export options involving liquefied natural gas (LNG), the West African Gas Pipeline (WAGP), and, in the future, other potentially large-scale export routes (e.g. to Europe through a Trans Saharan Gas Pipeline (TSGP). This paper reviews these gas utilization options, export potential, and government's policies that are stimulating gas investments in Nigeria. © 2014 Elsevier B.V. All rights reserved.

Vchirawongkwin V.,Chulalongkorn University | Kritayakornupong C.,King Mongkut's University of Technology Thonburi | Tongraar A.,Suranaree University of Technology | Rode B.M.,University of Innsbruck
Journal of Physical Chemistry B | Year: 2011

The ab initio quantum mechanical charge field molecular dynamics (QMCF MD) formalism was applied to simulate carbonate and nitrate anions in aqueous solution. The out-of-plane (2) spectra obtained from the velocity autocorrelation functions (VACFs) and the torsion angle-time functions indicate that the symmetry of carbonate is reduced from D3h to a lower degree by breaking up the molecular plane, whereas the planarity of nitrate anion is retained. The calculated frequencies are in good agreement with the Raman and IR data. Carbonate shows a stronger molecular hydration shell than the nitrate anion with the average molecular coordination numbers of 8.9 and 7.9, respectively. A comparison with the average number of ion-solvent hydrogen bonds (H-bonds) indicates the extra water molecules within the hydration shell of carbonate (∼2) and nitrate (∼3), readily migrating from one coordinating site to another. The mean residence times for water ligands in general classify carbonate and nitrate as moderate and weak structure-making anions, while the specific values for individual sites of nitrate reveal local weak structure-breaking properties. © 2011 American Chemical Society.

Thato R.,Chulalongkorn University
Journal of Pediatric and Adolescent Gynecology | Year: 2011

Study Objective: To determine whether, when controlling for confounding factors, there was still an association of adolescence with adverse outcomes. Design: Retrospective case control study. Setting: Seven Bangkok Metropolitan Administration General Hospitals. Participants: Charts of all women aged 19 and younger (n = 1,354) having singleton live births in 2004, 2005, and 2006 were retrieved. For the adult group, 1,389 charts of mothers between the ages of 20 and 34 delivering singleton babies were selected using proportionate systematic random sampling. Maternal age was divided into 3 groups: 11-15, 16-19, and 20-34. Main Outcome Measures: Obstetric and perinatal outcomes. Results: After statistically controlling for known confounding factors, teenage pregnancy was associated with increased risks of anemia (11-15: AOR = 1.81, P < 0.001; 16-19: AOR = 1.48, P < 0.01), very preterm deliveries (11-15: AOR = 2.18, P < 0.05), very low birth weight babies (11-15: AOR = 6.98, P < 0.05; 16-19: AOR = 9.86, P < 0.01), newborn admission to Intensive Care Unit (11-15: AOR = 1.93, P < 0.01; 16-19: AOR = 2.10, P < 0.01), and postpartum complications (11-15: AOR = 3.33, P < 0.01). The rates of cesarean delivery (11-15: AOR 0.58, P < 0.01; 16-19: AOR = 0.57, P < 0.01), operative delivery (11-15: AOR = 0.49, P < 0.01), and oxytocin augmentation (16-19: AOR = 0.66, P < 0.01) were less frequent in younger mothers. Conclusion: Independent of known confounding factors, teenage pregnancy was associated with increased risks of adverse maternal and neonatal outcomes requiring clinical and outreach interventions from health care providers. © 2011 North American Society for Pediatric and Adolescent Gynecology.

Krungkrai S.R.,Rangsit University | Krungkrai J.,Chulalongkorn University
Asian Pacific Journal of Tropical Biomedicine | Year: 2011

Plasmodium falciparum (P. falciparum) is responsible for the majority of life-threatening cases of human malaria, causing 1.5-2.7 million annual deaths. The global emergence of drug-resistant malaria parasites necessitates identification and characterization of novel drug targets and their potential inhibitors. We identified the carbonic anhydrase (CA) genes in P. falciparum. The pfCA gene encodes an α-carbonic anhydrase, a Zn2+-metalloenzme, possessing catalytic properties distinct from that of the human host CA enzyme. The amino acid sequence of the pfCA enzyme is different from the analogous protozoan and human enzymes. A library of aromatic/heterocyclic sulfonamides possessing a large diversity of scaffolds were found to be very good inhibitors for the malarial enzyme at moderate-low micromolar and submicromolar inhibitions. The structure of the groups substituting the aromatic-ureido- or aromatic-azomethine fragment of the molecule and the length of the parent sulfonamide were critical parameters for the inhibitory properties of the sulfonamides. One derivative, that is, 4-(3, 4-dichlorophenylureido)thioureido-benzenesulfonamide (compound 10) was the most effective in vitro P. falciparum CA inhibitor, and was also the most effective antimalarial compound on the in vitro P. falciparum growth inhibition. The compound 10 was also effective in vivo antimalarial agent in mice infected with Plasmodium berghei, an animal model of drug testing for human malaria infection. It is therefore concluded that the sulphonamide inhibitors targeting the parasite CA may have potential for the development of novel therapies against human malaria. © 2011 Asian Pacific Tropical Biomedical Magazine.

Pongpirul K.,Chulalongkorn University
Health Policy and Planning | Year: 2014

Mixed methods research has become increasingly popular in health systems. Qualitative approaches are often used to explain quantitative results and help to develop interventions or survey instruments. Mixed methods research is especially important in low-and middle-income country (LMIC) settings, where understanding social, economic and cultural contexts are essential to assess health systems performance. To provide researchers and programme managers with a guide to mixed methods research in health systems, we review the best resources with a focus on LMICs. We selected 10 best resources (eight peer-reviewed articles and two textbooks) based on their importance and frequency of use (number of citations), comprehensiveness of content, usefulness to readers and relevance to health systems research in resource-limited contexts. We start with an overview on mixed methods research and discuss resources that are useful for a better understanding of the design and conduct of mixed methods research. To illustrate its practical applications, we provide examples from various countries (China, Vietnam, Kenya, Tanzania, Zambia and India) across different health topics (tuberculosis, malaria, HIV testing and healthcare costs). We conclude with some toolkits which suggest what to do when mixed methods findings conflict and provide guidelines for evaluating the quality of mixed methods research. © 2013 The Author. All rights reserved.

Boonyaroj V.,Chulalongkorn University | Chiemchaisri C.,Kasetsart University | Chiemchaisri W.,Kasetsart University | Theepharaksapan S.,Kasetsart University | Yamamoto K.,University of Tokyo
Bioresource Technology | Year: 2012

The performance of two-stage membrane bioreactor (MBR) in term of toxic organic micro-pollutants removal was continuously monitored for 300. days under long sludge age condition. The phenolic compounds and phthalic acid esters (PAEs) in landfill leachate and treated water from MBR unit were quantified by solid phase extraction and gas chromatography-mass spectrometry. Priority pollutants in landfill leachate were phenolics and their degradation products i.e. 4-methyl-2,6-di-tert-butylphenol, bisphenol A at higher concentrations above 100. μg/l, PAEs i.e. dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate, and di (2-ethylhexyl) phthalate. It was found that MBR could remove phenolic compounds and PAEs by 77-96%. Biodegradation and adsorption mechanisms were responsible for their removals in MBR. Additionally, the retention of compounds during filtration through the fouled membrane was also found significant. This research shows that the removal of organic micro-pollutants in landfill leachate was improved under higher biomass concentration and longer sludge age conditions. © 2011 Elsevier Ltd.

Vchirawongkwin V.,Chulalongkorn University | Pribil A.B.,University of Innsbruck | Rode B.M.,University of Innsbruck
Journal of Computational Chemistry | Year: 2010

The ab initio quantum mechanical charge field molecular dynamics (QMCF MD) formalism was applied to simulate the bicarbonate ion, HCO3-, in aqueous solution. The difference in coordination numbers obtained by summation over atoms (6.6) and for the solvent-accessible surface (5.4) indicates the sharing of some water molecules between the individual atomic hydration shells. It also proved the importance to consider the hydration of the chemically different atoms individually for the evaluation of structural and dynamical properties of the ion. The orientation of water molecules in the hydration shell was visualized by the θ-tilt surface plot. The mean residence time in the surroundings of the HCO3- ion classify it generally as a structure-breaking ion, but the analysis of the individual ion-water hydrogen bonds revealed a more complex behavior of the different coordination sites. © 2009 Wiley Periodicals, Inc.

Laokuldilok T.,Chulalongkorn University | Shoemaker C.F.,University of California at Davis | Jongkaewwattana S.,Chiang Mai University | Tulyathan V.,Chulalongkorn University
Journal of Agricultural and Food Chemistry | Year: 2011

This study investigated the antioxidant content and activity of phenolic acids, anthocyanins, α-tocopherol and γ-oryzanol in pigmented rice (black and red rice) brans. After methanolic extraction, the DPPH free radical scavenging activity and antioxidant activity were measured. The pigmented rice bran extract had a greater reducing power than a normal rice bran extract from a long grain white rice. All bran extracts were highly effective in inhibiting linoleic acid peroxidation (60-85%). High-performance liquid chromatography (HPLC) analysis of antioxidants in rice bran found that γ-oryzanol (39-63%) and phenolic acids (33-43%) were the major antioxidants in all bran samples, and black rice bran also contained anthocyanins 18-26%. HPLC analysis of anthocyanins showed that pigmented bran was rich in cyanidin-3-glucoside (58-95%). Ferulic acid was the dominant phenolic acid in the rice bran samples. Black rice bran contained gallic, hydroxybenzoic, and protocatechuic acids in higher contents than red rice bran and normal rice bran. Furthermore, the addition of 5% black rice bran to wheat flour used for making bread produced a marked increase in the free radical scavenging and antioxidant activity compared to a control bread. © 2010 American Chemical Society.

Pasanphan W.,Kasetsart University | Buettner G.R.,University of Iowa | Chirachanchai S.,Chulalongkorn University
Carbohydrate Research | Year: 2010

A novel biopolymer-based antioxidant, chitosan conjugated with gallic acid (chitosan galloylate, chitosan-GA), is proposed. Electron paramagnetic resonance (EPR) demonstrates a wide range of antioxidant activity for chitosan-GA as evidenced from its reactions with oxidizing free radicals, that is, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), horseradish peroxidase (HRP)-H2O2, carbon-centered alkyl radicals, and hydroxyl radicals. The EPR spectrum of the radical formed on chitosan-GA was attributed to the semiquinone radical of the gallate moiety. The stoichiometry and effective concentration (EC50) of the DPPH free radical with chitosan-GA show that the radical scavenging capacity is maintained even after thermal treatment at 100 °C for an hour. Although the degree of substitution of GA on chitosan was about 15%, its antioxidant capacity, that is, the reaction with carbon-centered and hydroxyl radicals, is comparable to that of GA. © 2009 Elsevier Ltd.

Karndumri P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2012

Some admissible gauge groups of N = 4 Chern-Simons gauged supergravity in three dimensions with exceptional scalar manifolds G 2(2)/SO(4), F 4(4)/USp(6) × SU(2), E 6(2)/SU(6)×SU(2), E 7(-5)/SO(12)×SU(2) and E 8(-24)/E 7×SU(2) are identified. In particular, a complete list of all possible gauge groups is given for the theory with G 2(2)/SO(4) coset space. We also study scalar potentials for all of these gauge groups and find some critical points. In the case of F 4(4)/USp(6) × SU(2) target space, we give some semisimple gauge groups which are maximal subgroups of F 4(4). Most importantly, we construct the SO(4) ⋉ T 6 gauged supergravity which is equivalent to N = 4 SO(4) Yang-Mills gauged supergravity. The latter is proposed to be obtained from an S 3 reduction of (1,0) six dimensional supergravity coupled to two vector and two tensor multiplets. The scalar potential of this theory on the scalar fields which are invariant under SO(4) is explicitly computed. Depending on the value of the coupling constants, the theory admits both dS and AdS vacua when all of the 28 scalars vanish. The maximal N = 4 supersymmetric AdS 3 should correspond to the AdS 3 × S 3 solution of the (1, 0) six dimensional theory. Finally, some gauge groups of the theories with E 6(2)/SU(6)×SU(2), E 7(-5)/SO(12)×SU(2) and E 8(-24)/E 7 × SU(2) scalar manifolds are identified. © 2012 SISSA.

Karndumri P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2012

We explicitly construct two Chern-Simons gauged supergravities in three dimensions with N = 4 and N = 8 supersymmetries and non-semisimple gauge groups. The N = 4 theory has scalar manifold SO(4,3)/SO(4) × SO(3) with the gauge group SO(3) ⋉ (T 3, T̂ 3). The theory describes (1, 0) six dimensional supergravity reduced on an SU(2) group manifold. The equivalent Yang-Mills type gauged supergravity has SO(3) gauge group coupled to three massive vector fields. The N = 8 theory is described by SO(8,8)/SO(8) × SO(8) scalar manifold, and the gauge group is given by SO(8) ⋉ T 28. The theory is a truncation of the SO(8) ⋉ T 28 gauged N = 16 theory with scalar manifold E8(8)/SO(16) and can be obtained by an S 7 compactification of type I theory in ten dimensions. Domain wall solutions of both gauged supergravities are analytically found and can be uplifted to higher dimensions. These provide domain wall vacua in the three dimensional gauged supergravity framework which might be useful for the study of Domain Wall 3/QFT 2 correspondence.© 2012 SISSA.

Klaykruayat B.,Chulalongkorn University | Siralertmukul K.,Chulalongkorn University | Srikulkit K.,Chulalongkorn University
Carbohydrate Polymers | Year: 2010

The cationic hyperbranched dendritic polyamidoamine (PAMAM) containing terminal methyl ester end groups was synthesized and then employed for modifying flake chitosan. The synthesis was achieved using repetitive reactions between Michael addition and amidation to obtain the methyl ester group terminated hyperbranched PAMAM, and then the methyl ester terminated hyperbranched dendritic PAMAM (PAMAM-ester) was methylated with dimethyl sulphate. The subsequent modification of chitosan with the cationic hyperbranched PAMAM-ester was carried out at room temperature for 5 days. As a result, cationic hyperbranched PAMAM modified chitosan was achieved. Characterizations by elemental analysis, FT-IR, NMR, TGA and XRD were employed to investigate the structural changes of chitosan to confirm its configuration. The cationic hyperbranched PAMAM-chitosan was applied onto cotton fabric at 1 wt.% add-on using a padding method and was found to have a good antimicrobial performance against Staphylococcus aureus compared to that obtained with unmodified chitosan. © 2009 Elsevier Ltd. All rights reserved.

Suttinun O.,Prince of Songkla University | Luepromchai E.,Chulalongkorn University | Muller R.,TU Hamburg - Harburg
Reviews in Environmental Science and Biotechnology | Year: 2013

Due to its toxicity and persistence in the environment, trichloroethylene (TCE) has become a major soil and groundwater contaminant in many countries. A group of aliphatic- and aromatic-degrading bacteria expressing nonspecific oxygenases have been reported to transform TCE through aerobic cometabolism in the presence of primary substrate such as methane, ammonia, propane, phenol, toluene or cumene. This paper reviews the fundamentals and results of TCE cometabolism from laboratory and field studies. The limitations associated with TCE cometabolism including the causes and effects of substrate and/or inducer utilization rate and depletion, enzyme inhibition and inactivation, and cytotoxicity during TCE oxidation among various TCE-degrading bacteria and enzymes are discussed. In addition, the potential strategies e. g. addition of primary substrate/inducer or external energy substrate, use of a two-stage reactor and application of cell immobilization for sustained TCE degradation are highlighted. The review summarizes important information on TCE cometabolism, which is necessary for developing efficient TCE bioremediation approaches. © 2012 Springer Science+Business Media B.V.

Ponprateep S.,Chulalongkorn University | Tharntada S.,Kasetsart University | Somboonwiwat K.,Chulalongkorn University | Tassanakajon A.,Chulalongkorn University
Fish and Shellfish Immunology | Year: 2012

Anti-lipopolysaccharide factors (ALFs) are antimicrobial peptides previously identified in various crustaceans. Out of five isoforms identified in Penaeus monodon, ALF. Pm3 is the best characterized, exhibits antibacterial and antifungal activities and can protect the shrimp from viral infections. Herein, the most recent identified ALF. Pm, called ALF. Pm6, is characterized for its potential role in the shrimp's immunity. RNA interference-mediated gene silencing was used to study the function of ALF. Pm6 in comparison to ALF. Pm3. Knockdown of ALF. Pm3 gene led to rapid death with a cumulative shrimp mortality of 86% within 7 days, accompanied by a 12- and 50-fold higher bacterial count after 2 days in the haemolymph and hepatopancreas, respectively, compared to the control shrimp injected with GFP dsRNA. In contrast, gene silencing of ALF. Pm6 alone had no effect on the shrimp mortality, but led to a significant increase in the cumulative mortality and a faster mortality rate following Vibrio harveyi and white spot syndrome virus (WSSV) infections, respectively. These results support the roles of ALF. Pm6 and ALF. Pm3 in the protection of shrimp against microbial infections. © 2011 Elsevier Ltd.

Jirutitijaroen P.,National University of Singapore | Kim S.,National University of Singapore | Kittithreerapronchai O.,Chulalongkorn University | Prina J.,University of Santiago de Chile
Applied Energy | Year: 2013

This paper considers a deregulated electricity market environment where a natural gas-fired generation company can engage in different types of contracts to manage its natural gas supply as well as trade on the electricity market. If the contracts are properly designed, they can protect the company from fluctuations in electricity price and demand, at some cost to the company's expected profit. This reduction in profit can be mitigated by trading on the natural gas and electricity spot markets, but this trading activity may also sometimes result in losses. A stochastic programming model is formulated to capture the hedging decisions made by the company, as well as the interactions between the natural gas and electricity markets. The benefits offered by this approach for profit maximization in a variety of business scenarios, such as the case where the company can hold some amount of gas in storage are studied and presented. It is found that the stochastic model enables the company to optimize the electricity generation schedule and the natural gas consumption, including spot price transactions and gas storage management. Several managerial insights into the natural gas market, natural gas storage, and distribution profit are given. © 2013 Elsevier Ltd.

Vchirawongkwin V.,Chulalongkorn University | Kritayakornupong C.,King Mongkut's University of Technology Thonburi | Rode B.M.,University of Innsbruck
Journal of Physical Chemistry B | Year: 2010

The ab initio quantum mechanical charge field molecular dynamics (QMCF MD) formalism was applied to simulate the bisulfate ion, HSO4 -, in aqueous solution. The averaged geometry of bisulfate ion supports the separation of six normal modes of the O-SO3 unit with C3v symmetry from three modes of the OH group in the evaluation of vibrational spectra obtained from the velocity autocorrelation functions (VACFs) with subsequent normal coordinate analyses. The calculated frequencies are in good agreement with the observations in Raman and IR experiments. The difference of the averaged coordination number obtained for the whole molecule (8.0) and the summation over coordinating sites (10.9) indicates some water molecules to be located in the overlapping volumes of individual hydration spheres. The averaged number of hydrogen bonds (H-bonds) during the simulation period (5.8) indicates that some water molecules are situated in the molecular hydration shell with an unsuitable orientation to form a hydrogen bond with the ion. The mean residence time in the surroundings of the bisulfate ion classify it generally as a weak structure-making ion, but the analysis of the individual sites reveals a more complex behavior of them, in particular a strong interaction with a water molecule at the hydrogen site. © 2010 American Chemical Society.

Karndumri P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2013

We study critical points of F (4) gauged supergravity in six dimensions coupled to three vector multiplets. Scalar fields are described by ℝ+×SO(4,3/SO(4)×SO(3) coset space, and the gauge group is given by SO(3)R × SO(3) with SO(3)R being the R-symmetry. We identify new non-supersymmetric critical points of the scalar potential. One of these new critical points is shown to be stable with all scalar masses above the BF bound and should correspond to a new non-supersymmetric CFT in five dimensions. On the other hand, the maximally supersymmetric critical point with all scalars vanishing is dual to an SCFT 5 arising from a near horizon geometry of the D4-D8 brane system in type I′ theory with an enhanced global symmetry E1 ∼ SU(2). We give a numerical RG flow solution interpolating between this SCFT and the new stable critical point. The flow describes a non-supersymmetric deformation driven by relevant operators of dimension 3. We identify the dual operators with the mass terms for hypermultiplet scalars in the dual field theory. The solution provides another example of holographic RG flows in AdS6/CFT5 correspondence. © 2013 SISSA, Trieste, Italy.

Xu L.D.,CAS Institute of Computing Technology | Xu L.D.,Old Dominion University | Viriyasitavat W.,Chulalongkorn University | Ruchikachorn P.,Chulalongkorn University | Martin A.,University of Oxford
IEEE Transactions on Industrial Informatics | Year: 2012

This paper presents a requirement-oriented automated framework for formal verification of service workflows. It is based on our previous work describing the requirement-oriented service workflow specification language called SWSpec. This language has been developed to facilitate workflow composer as well as arbitrary services willing to participate in a workflow to formally and uniformly impose their own requirements. As such, SWSpec provides a formal way to regulate and control workflows. The key component of the to-be-proposed framework centers on verification algorithms that rely on propositional logic. We demonstrate that logic-based workflow verification can be applied to SWSpec which is capable of checking compliance and also detecting conflicts of the imposed requirements. By automating compliance checking process, this framework will support scalable services interoperation in the form of workflows in opened environments. © 2005-2012 IEEE.

Chatdarong K.,Chulalongkorn University | Thuwanut P.,Chulalongkorn University
Theriogenology | Year: 2010

The objectives were to determine the: 1) extent of epithelial and red blood cell contamination in epididymal cat sperm samples recovered by the cutting method; 2) efficacy of simple washing, single-layer centrifugation (SLC), and swim-up for selecting epididymal cat sperm; and 3) effects of freezing and thawing on cat sperm selected by various techniques. Ten unit samples were studied; each contained sperm from the cauda epididymides of four cats (total, ∼200 × 106 sperm) and was equally allocated into four treatments: 1) simple washing, 2) single-layer centrifugation through colloid prior to cryopreservation (SLC-PC), 3) single-layer centrifugation through colloid after cryopreservation (SLC-AC), and 4) swim-up. Centrifugation (300 × g for 20 min) was done for all methods. The SLC-PC had a better recovery rate than the SLC-AC and swim-up methods (mean ± SD of 16.4 ± 8.7, 10.7 ± 8.9, and 2.3 ± 1.7%, respectively; P < 0.05). The SLC-PC, SLC-AC and swim-up samples contained less red blood cell contamination than simple washed samples (0.02 ± 0.01, 0.02 ± 0.04, 0.03 ± 0.04, and 0.44 ± 0.22 × 106 cells/mL, respectively; P < 0.05). Although the proportion of sperm with head abnormalities did not differ among selection methods (P > 0.05), SLC-PC yielded the highest percentage of sperm with normal midpieces and tails (P < 0.05), due to the lowest proportion of coiled tails (P < 0.05). Furthermore, the SLC-PC was as effective as swim-up in removing sperm with proximal droplets, and selecting motile sperm, as well as those with intact membranes and DNA (P > 0.05). In conclusion, both SLC-PC and swim-up improved the quality of epididymal cat sperm, including better morphology, membrane and DNA integrity, and removal of cellular contamination. However, SLC had a better sperm recovery rate than swim-up. © 2010 Elsevier Inc. All rights reserved.

Yoksan R.,Kasetsart University | Chirachanchai S.,Chulalongkorn University
Materials Science and Engineering C | Year: 2010

The fabrication of silver nanoparticles was accomplished by γ-ray irradiation reduction of silver nitrate in a chitosan solution. The obtained nanoparticles were stable in the solution for more than six months, and showed the characteristic surface plasmon band at 411 nm as well as a positively charged surface with 40.4 ± 2.0 mV. The silver nanoparticles presented a spherical shape with an average size of 20-25 nm, as observed by TEM. Minimum inhibitory concentration (MIC) against E. coli, S. aureus and B. cereus of the silver nanoparticles dispersed in the γ-ray irradiated chitosan solution was 5.64 μg/mL. The silver nanoparticle-loaded chitosan-starch based films were prepared by a solution casting method. The incorporation of silver nanoparticles led to a slight improvement of the tensile and oxygen gas barrier properties of the polysaccharide-based films, with diminished water vapor/moisture barrier properties. In addition, silver nanoparticle-loaded films exhibited enhanced antimicrobial activity against E. coli, S. aureus and B. cereus. The results suggest that silver nanoparticle-loaded chitosan-starch based films can be feasibly used as antimicrobial materials for food packaging and/or biomedical applications. © 2010 Elsevier B.V. All rights reserved.

Aribarg T.,Rangsit University | Supratid S.,Rangsit University | Lursinsap C.,Chulalongkorn University
Applied Intelligence | Year: 2012

The advantage of efficient searches belonging to ant-miner over several other approaches leads to prominent achievements on rules mining. Fuzzy ant-miner, an extension of the ant-miner provides a fuzzy mining framework for the automatic extraction of fuzzy rules from labeled numerical data. However, it is easily trapped in local optimal, especially when it applies to medical cases, where real world accuracy is elusive; and the interpretation and integration of medical knowledge is necessary. In order to relieve such a local optimal difficulty, this paper proposes OMFAM which applies simulated annealing to optimize fuzzy set parameters associated with a modified fuzzy ant-miner (MFAM). MFAM employs attributes and training case weighting. The proposed method, OMFAMwas experimented with six critical medical cases for developing efficient medical diagnosis systems. The performance measurement relates to accuracy as well as interpretability of the mined rules. The performance of the OMFAM is compared with such references as MFAM, fuzzy ant-miner (FAM), and other classification methods. At last, it indicates the superiority of the OMFAM algorithm over the others.. © 2011 Springer Science+Business Media, LLC.

Karndumria P.,Chulalongkorn University | Colgain E.O.,University of Oviedo
Journal of High Energy Physics | Year: 2013

AdS3 solutions dual to N = (0, 2) SCFTs arise when D3-branes wrap Kähler two-cycles in manifolds with SU(4) holonomy. Here we review known AdS3 solutions and identify the corresponding three-dimensional gauged supergravities, solutions of which uplift to type IIB supergravity. In particular, we discuss gauged supergravities dual to twisted compactifications on Riemann surfaces of both N = 4 SYM and N = 1 SCFTs with Sasaki-Einstein duals. We check in each case that c-extremization gives the exact central charge and R symmetry. For completeness, we also study AdS3 solutions from intersecting D3-branes, generalise recent KK reductions of Detournay & Guica and identify the underlying gauged supergravities. Finally, we discuss examples of null-warped AdS3 solutions to three-dimensional gauged supergravity, all of which embed in string theory © SISSA 2013.

Karndumri P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2013

We explicitly construct N = 10 Chern-Simons gaged supergravity in three dimensions with non-semisimple gauge group SO(5) × T10. The gauge group is embedded in E6(-14) which is the isometry group of the 32-dimensional scalar manifold E6(-14)/SO(10) x U(1). The resulting theory is on-shell equivalent to SO(5) Yang-Mills gauged supergravity coming from dimensional reduction on S1 of SO(5) N = 5 gauged supergravity in four dimensions. We discuss the spectrum of the corresponding reduction. The SO(5) × T10 gauged supergravity, describing the reduced theory, admits a 1/22-BPS domain wall vacuum solution whose explicit form is also given. This provides an example of a domain wall in non-maximal gauged supergravity. © SISSA 2013.

Hengsritawat V.,Chulalongkorn University | Tayjasanant T.,Chulalongkorn University | Nimpitiwan N.,Bangkok University
International Journal of Electrical Power and Energy Systems | Year: 2012

This paper presents a probabilistic approach to design an optimal size of photovoltaic distributed generator (PV-DG) in a distribution system. A steady-state voltage stability index is applied to select PV-DG locations. The objective of the proposed technique is to minimize average system active power losses, while considering power quality constraints (i.e., voltage regulation, total harmonic voltage distortion, total demand distortion and harmonic currents). Monte Carlo simulation is applied to acquire solar radiations, ambient temperatures, load demands and substation voltages. The proposed technique is tested on an actual 51-bus medium voltage distribution system in Thailand. From simulations, there is a different solution between selecting the optimal size of PV-DG from with and without considering background harmonics. Also in realistic cases, PV-DGs may improve voltage regulation and decrease losses in distribution systems; however, increase total harmonic voltage distortion values. © 2012 Elsevier Ltd. All rights reserved.

Agency: European Commission | Branch: FP7 | Program: CP-SICA | Phase: NMP.2012.2.2-6 | Award Amount: 5.12M | Year: 2012

Limpid aims at generating new knowledge on photocatalytic materials and processes in order to develop novel depollution treatments with enhanced efficiency and applicability. The main goal of LIMPID is to develop materials and technologies based on the synergic combination of different types of nanoparticles (NPs) into a polymer host to generate innovative nanocomposites which can be actively applied to the catalytic degradation of pollutants and bacteria, both in air or in aqueous solution. Single component nanocomposites including TiO2 NPs are already known for their photocatalytic activities. LIMPID will aim at going one big step further and include, into one nanocomposite material, oxide NPs and metal NPs in order to increase the photocatalytic efficiency and allow the use of solar energy to activate the process. One of the main challenge of LIMPID is to design host polymers, such as hybrid organic inorganic and fluorinated polymers, since photocatalysts can destroy the organic materials. The incorporation of NPs in polymers will allow to make available the peculiar nano-object properties and to merge the distinct components into a new original class of catalysts. At the same time nanocomposite formulation will also prevent NPs to leach into water and air phase, thus strongly limiting the potential threat associated to dispersion of NPs into the environment. Therefore nanocomposites developed in LIMPID will be used as coating materials and products for the catalytic degradation of pollutants and bacteria in water and air, i.e. deposited onto re-usable micro-particles, or in pollutant degradation reactors, and even onto large surfaces, as a coating or paint. In addition such new class of nanocomposites will be also exploited for the fabrication of porous membranes for water treatment. In order to fulfill its objectives, the LIMPID consortium has been designed to combine leading industrial partners with research groups from Europe, ASEAN Countries and Canada.

News Article | February 15, 2017

Thailand has become the first Asian country to eliminate mother-to-child transmission (MTCT) of HIV, thanks to a pragmatic multi-sector response backed by strong political commitment and heavy government investment, a study published in Paediatrics and International Child Health reports. Such an early, concerted response allowed the country to successfully address the four prongs of the recommended World Health Organization (WHO) elimination strategy. As a result, MTCT rates were reduced from 20-40% in the mid-1990s to 1.9% in 2015 (surpassing the WHO elimination target of The WHO strategy focuses on the following four prongs: primary prevention of HIV in women of childbearing age; prevention of unintended pregnancies in women living with HIV; prevention of HIV transmission from an HIV-infected woman to her infant; and provision of appropriate treatment, care and support to women and children living with HIV. In Thailand, initiatives to promote condom use, provide information about the risk of transmission and introduce testing for pregnant and post-partum women were successfully implemented. For example, the 100% Condom Programme, which promotes 100% condom use by male patrons of commercial sex workers, has played a crucial role in preventing HIV infection in women of reproductive age. The success of such initiatives resulted in part from strong political leadership - the national AIDS policy of Thailand was transferred from the Ministry of Public Health to the Office of the Prime Minister in 1991 - and greatly increased investment, with government spending on the HIV/AIDS programme rising from US$684,000 in 1988 to US$82 million by 1997. The high rate of antenatal care provision in Thailand is also key. A voluntary HIV test with same-day results is offered at the first clinic visit, followed by re-testing later in pregnancy for HIV-negative women. For HIV-infected pregnant women, antiretroviral therapy (ART) is provided as soon as possible. Such treatment is now available at much lower cost, thanks to legislative changes which have allowed the non-commercial production of generic ART in Thailand. Counselling services at antenatal clinics also promote the use of dual methods of contraception to prevent unintended pregnancy in women with HIV. The study's author, Professor Usa Thisyakorn of Chulalongkorn University, Bangkok said: "Thailand has achieved WHO elimination of mother-to-child HIV transmission targets with early and concerted efforts of all sectors of Thai society. This provided numerous lessons learned in working together to safeguard children. Since children are the country's future, how the country responds to the problems created for them indicates how highly the country values its future." When referencing the article: Please include Journal title, author, published by Taylor & Francis and the following statement: Please note the article will not be available online until the embargo has been lifted. Taylor & Francis Group partners with researchers, scholarly societies, universities and libraries worldwide to bring knowledge to life. As one of the world's leading publishers of scholarly journals, books, ebooks and reference works our content spans all areas of Humanities, Social Sciences, Behavioural Sciences, Science, and Technology and Medicine. From our network of offices in Oxford, New York, Philadelphia, Boca Raton, Boston, Melbourne, Singapore, Beijing, Tokyo, Stockholm, New Delhi and Johannesburg, Taylor & Francis staff provide local expertise and support to our editors, societies and authors and tailored, efficient customer service to our library colleagues. For more information please contact: Sayjal Mistry, Press & Media Relations Coordinator email: Follow us on Twitter: @tandfnewsroom Introducing Press Pass: journalist access to all Taylor & Francis Journal articles. Contact us for more details.

News Article | December 20, 2016

Astronomers have gotten their first look at exactly where most of today's stars were born. To do so, they used the National Science Foundation's Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) to look at distant galaxies seen as they were some 10 billion years ago. At that time, the Universe was experiencing its peak rate of star formation. Most stars in the present Universe were born then. "We knew that galaxies in that era were forming stars prolifically, but we didn't know what those galaxies looked like, because they are shrouded in so much dust that almost no visible light escapes them," said Wiphu Rujopakam, of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo and Chulalongkorn University in Bangkok, who was lead author on the research paper. Radio waves, unlike visible light, can get through the dust. However, in order to reveal the details of such distant -- and faint -- galaxies, the astronomers had to make the most sensitive images ever made with the VLA. The new observations, using the VLA and ALMA, have answered longstanding questions about just what mechanisms were responsible for the bulk of star formation in those galaxies. They found that intense star formation in the galaxies they studied most frequently occured throughout the galaxies, as opposed to much smaller regions in present-day galaxies with similar high star-formation rates. The astronomers used the VLA and ALMA to study galaxies in the Hubble Ultra Deep Field, a small area of sky observed since 2003 with NASA's Hubble Space Telescope (HST). The HST made very long exposures of the area to detect galaxies in the far-distant Universe, and numerous observing programs with other telescopes have followed up on the HST work. "We used the VLA and ALMA to see deeply into these galaxies, beyond the dust that obscured their innards from Hubble," said Kristina Nyland, of the National Radio Astronomy Observatory (NRAO). "The VLA showed us where star formation was occurring, and ALMA revealed the cold gas that is the fuel for star formation," she added. "In this study, we made the most sensitive image ever made with the VLA," said Preshanth Jagannathan, also of NRAO. "If you took your cellphone, which transmits a weak radio signal, and put it at more than twice the distance to Pluto, near the outer edge of the solar system, its signal would be roughly as strong as what we detected from these galaxies," he added. The study of the galaxies was done by an international team of astronomers. Others involved include James Dunlop of the University of Edinburgh and Rob Ivison of the University of Edinburgh and the European Southern Observatory. The researchers reported their findings in the Dec. 1 issue of the Astrophysical Journal. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of South Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

News Article | December 20, 2016

At that time, the Universe was experiencing its peak rate of star formation. Most stars in the present Universe were born then. "We knew that galaxies in that era were forming stars prolifically, but we didn't know what those galaxies looked like, because they are shrouded in so much dust that almost no visible light escapes them," said Wiphu Rujopakam, of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo and Chulalongkorn University in Bangkok, who was lead author on the research paper. Radio waves, unlike visible light, can get through the dust. However, in order to reveal the details of such distant—and faint—galaxies, the astronomers had to make the most sensitive images ever made with the VLA. The new observations, using the VLA and ALMA, have answered longstanding questions about just what mechanisms were responsible for the bulk of star formation in those galaxies. They found that intense star formation in the galaxies they studied most frequently occured throughout the galaxies, as opposed to much smaller regions in present-day galaxies with similar high star-formation rates. The astronomers used the VLA and ALMA to study galaxies in the Hubble Ultra Deep Field, a small area of sky observed since 2003 with NASA's Hubble Space Telescope (HST). The HST made very long exposures of the area to detect galaxies in the far-distant Universe, and numerous observing programs with other telescopes have followed up on the HST work. "We used the VLA and ALMA to see deeply into these galaxies, beyond the dust that obscured their innards from Hubble," said Kristina Nyland, of the National Radio Astronomy Observatory (NRAO). "The VLA showed us where star formation was occurring, and ALMA revealed the cold gas that is the fuel for star formation," she added. "In this study, we made the most sensitive image ever made with the VLA," said Preshanth Jagannathan, also of NRAO. "If you took your cellphone, which transmits a weak radio signal, and put it at more than twice the distance to Pluto, near the outer edge of the solar system, its signal would be roughly as strong as what we detected from these galaxies," he added. The study of the galaxies was done by an international team of astronomers. Others involved include James Dunlop of the University of Edinburgh and Rob Ivison of the University of Edinburgh and the European Southern Observatory. The researchers reported their findings in the Dec. 1 issue of the Astrophysical Journal. Explore further: Forming stars in the early universe More information: W. Rujopakarn et al. VLA AND ALMA IMAGING OF INTENSE GALAXY-WIDE STAR FORMATION IN∼ 2 GALAXIES, The Astrophysical Journal (2016). DOI: 10.3847/0004-637X/833/1/12 ,

Morris G.,Tir Na Nog | Maes M.,Deakin University | Maes M.,Chulalongkorn University
Metabolic Brain Disease | Year: 2014

Myalgic encephalomyelitis / chronic fatigue syndrome (ME/cfs) is classified by the World Health Organization as a disorder of the central nervous system. ME/cfs is an neuro-immune disorder accompanied by chronic low-grade inflammation, increased levels of oxidative and nitrosative stress (O&NS), O&NS-mediated damage to fatty acids, DNA and proteins, autoimmune reactions directed against neoantigens and brain disorders. Mitochondrial dysfunctions have been found in ME/cfs, e.g. lowered ATP production, impaired oxidative phosphorylation and mitochondrial damage. This paper reviews the pathways that may explain mitochondrial dysfunctions in ME/cfs. Increased levels of pro-inflammatory cytokines, such as interleukin-1 and tumor necrosis factor-α, and elastase, and increased O&NS may inhibit mitochondrial respiration, decrease the activities of the electron transport chain and mitochondrial membrane potential, increase mitochondrial membrane permeability, interfere with ATP production and cause mitochondrial shutdown. The activated O&NS pathways may additionally lead to damage of mitochondrial DNA and membranes thus decreasing membrane fluidity. Lowered levels of antioxidants, zinc and coenzyme Q10, and ω3 polyunsaturated fatty acids in ME/cfs may further aggravate the activated immuno-inflammatory and O&NS pathways. Therefore, it may be concluded that immuno-inflammatory and O&NS pathways may play a role in the mitochondrial dysfunctions and consequently the bioenergetic abnormalities seen in patients with ME/cfs. Defects in ATP production and the electron transport complex, in turn, are associated with an elevated production of superoxide and hydrogen peroxide in mitochondria creating adaptive and synergistic damage. It is argued that mitochondrial dysfunctions, e.g. lowered ATP production, may play a role in the onset of ME/cfs symptoms, e.g. fatigue and post exertional malaise, and may explain in part the central metabolic abnormalities observed in ME/cfs, e.g. glucose hypometabolism and cerebral hypoperfusion. © 2013 Springer Science+Business Media.

Kampitak T.,Chulalongkorn University | Suwanpimolkul G.,Chulalongkorn University | Browne S.,National Institute of Allergy and Infectious Diseases | Suankratay C.,Chulalongkorn University
Infection | Year: 2011

Immune defects in interleukin-12-dependent interferon-gamma (IFN-γ) pathways are associated with disseminated infections caused by non-tuberculous mycobacteria (NTM) and Salmonella. Recently, there have been an increasing number of reports of acquired autoantibodies to IFN-γ in adults, especially in Asian patients. We describe here three human immunodeficiency virus-negative Thai adults who had persistent or recurrent disseminated infections caused by NTM, Salmonella, and other opportunistic pathogens, possibly due to anti-IFN-γ autoantibodies. The antibodies were shown to exhibit very high inhibitory activity to IFN-γ. Two patients also developed Sweet's syndrome during the course of infections. In addition, we also review all previous reports of patients with anti-IFN-γ antibodies who were susceptible to NTM and Salmonella infections. © 2010 Urban & Vogel.

Naowaratwattana W.,Chulalongkorn University | De-Eknamkul W.,Chulalongkorn University | De Mejia E.G.,University of Illinois at Urbana - Champaign
Journal of Medicinal Food | Year: 2010

The entire plant of Morus alba L. (Family Moraceae), or mulberry, possesses medical benefits, including anticancer properties. In this study, we investigated the effect of mulberry leaf extracts on the human hepatoma HepG2 cell line, which is related to hepatocellular carcinoma. Mulberry leaf extracts were prepared using four solvents, each with different polarities: 100% methanol (MeOH), 50% aqueous MeOH, 1-butanol (BuOH), and hot water (W). The phenolic profile, total polyphenol content, antioxidant capacity, and effect on human hepatoma HepG2 cells of the leaf extracts were analyzed by examining cytotoxicity, cell cycle progression, apoptosis, expression of topoisomerase IIα, and proteins involved in cell cycle progression. High-performance liquid chromatography-mass spectrometry analysis revealed that 100% MeOH, 50% MeOH, and BuOH extracts contained rutin, isoquercetin, and various derivatives of kaempferol and quercetin glycosides as their major constituents; the W extract contained primarily chlorogenic acid and caffeoylquinic acid derivatives. Total phenolic content based on rutin equivalents was 17.1%, 9.6%, 8.3%, and 6.5% of dry 100% MeOH, 50% MeOH, BuOH, and W extracts, respectively. 2,2-Diphenyl-1-picrylhydrazyl radical scavenging activities were 70.0%, 45.8%, 41.0%, and 33.6%, and 50% inhibitory concentration values were 33.1, 79.4, 35.6, and 204.2 μg/mL for HepG2 cell proliferation inhibition for 100% MeOH, 50% MeOH, BuOH, and W extracts, respectively. MeOH extracts caused cell cycle G2/M arrest and induced the caspase cascade and apoptosis, but the W extract had very little effect on cell cycle progression. MeOH extracts reduced the level of topoisomerase IIα but increased the level of p27Kip1, with no significant effect on p21Cip1/waf1. Therefore, we concluded that phenolic-containing organic extracts of mulberry leaves inhibit the growth of HepG2 hepatoma cells through coordinated actions of inducing cell cycle arrest in the G2/M phase (with p27Kip1 protein expression), inhibiting topoisomerase IIα activity, and inducing cell apoptosis by activation of caspases. © 2010, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition.

Trisirisatayawong I.,Chulalongkorn University | Naeije M.,Technical University of Delft | Simons W.,Technical University of Delft | Fenoglio-Marc L.,TU Darmstadt
Global and Planetary Change | Year: 2011

Investigation of long-term tidal data and short-term altimetry measurements reveals that sea level in the Gulf of Thailand is rising significantly faster than global average rates. Upward land motion detected from repeated precise GPS campaign measurements is used to correct the apparent sea level change from tide gauge, yielding absolute long-term trends as follows: Sattahip (1942-2004) 5.0 ± 1.3 mm/yr, Ko Sichang (1940-1999) 4.5 ± 1.3. mm/yr and Ko Mattaphon (1964-2004) 4.4 ± 1.1. mm/yr. Dual-crossover minimization of multi-mission altimetry data covering the 1993-2009 period reveals the following absolute sea level rates: Sattahip 4.8 ± 0.7. mm/yr, Ko Sichang 5.8 ± 0.8. mm/yr, Ko Lak 3.6 ± 0.7. mm/yr and Ko Mattaphon 3.2 ± 0.7. mm/yr. In other parts of the Gulf, the 1993-2009 rising rates are also in the range of 3 to 5.5. mm/yr. In the entire Gulf we don't find any evidence of sea level falling. At Ko Lak where the collocation of Topex-class altimetry ground track and the tidal station is extremely good, vertical land motion derived from the difference of sea level change rates detected by altimetry and tidal data is used to correct the apparent rate, yielding an absolute long-term (1940-2004) rate of 3.0 ± 1.5. mm/yr. The differences between the altimetry-based rates and the absolute tide gauge sea level trends can be explained by interannual variations like ENSO and decadal variations due to solar activity and lunar nutation. Post-2004 tidal data have been treated separately in our study because reliable values of region-wide vertical co-seismic displacements and post-seismic velocities caused by the 2004 Mw9.2 Sumatra-Andaman earthquake are still not accurately known. Exclusion of these data will not significantly change the determined long-term absolute sea level change rates because of the relatively short time span of post-earthquake sea level data compared to the complete tidal record. The impact of fast rising sea level combined with high rates of post-seismic downward crustal motions as indicated by GPS data makes coastal areas and river estuaries along the Gulf of Thailand highly vulnerable to flooding, particularly the low-lying city of Bangkok. © 2011 Elsevier B.V.

Morris G.,Tir Na Nog | Berk M.,Deakin University | Berk M.,University of Melbourne | Walder K.,Deakin University | And 2 more authors.
BMC Medicine | Year: 2015

Background: The genesis of severe fatigue and disability in people following acute pathogen invasion involves the activation of Toll-like receptors followed by the upregulation of proinflammatory cytokines and the activation of microglia and astrocytes. Many patients suffering from neuroinflammatory and autoimmune diseases, such as multiple sclerosis, Parkinson's disease and systemic lupus erythematosus, also commonly suffer from severe disabling fatigue. Such patients also present with chronic peripheral immune activation and systemic inflammation in the guise of elevated proinflammtory cytokines, oxidative stress and activated Toll-like receptors. This is also true of many patients presenting with severe, apparently idiopathic, fatigue accompanied by profound levels of physical and cognitive disability often afforded the non-specific diagnosis of chronic fatigue syndrome. Discussion: Multiple lines of evidence demonstrate a positive association between the degree of peripheral immune activation, inflammation and oxidative stress, gray matter atrophy, glucose hypometabolism and cerebral hypoperfusion in illness, such as multiple sclerosis, Parkinson's disease and chronic fatigue syndrome. Most, if not all, of these abnormalities can be explained by a reduction in the numbers and function of astrocytes secondary to peripheral immune activation and inflammation. This is also true of the widespread mitochondrial dysfunction seen in otherwise normal tissue in neuroinflammatory, neurodegenerative and autoimmune diseases and in many patients with disabling, apparently idiopathic, fatigue. Given the strong association between peripheral immune activation and neuroinflammation with the genesis of fatigue the latter group of patients should be examined using FLAIR magnetic resonance imaging (MRI) and tested for the presence of peripheral immune activation. Summary: It is concluded that peripheral inflammation and immune activation, together with the subsequent activation of glial cells and mitochondrial damage, likely account for the severe levels of intractable fatigue and disability seen in many patients with neuroimmune and autoimmune diseases. This would also appear to be the case for many patients afforded a diagnosis of Chronic Fatigue Syndrome. © Morris et al.

Nuntadusit C.,Prince of Songkla University | Wae-hayee M.,Prince of Songkla University | Bunyajitradulya A.,Chulalongkorn University | Eiamsa-ard S.,Mahanakorn University of Technology
International Communications in Heat and Mass Transfer | Year: 2012

The flow and heat transfer characteristics of multiple swirling impinging jets (M- SIJs) with 3 × 3 in-line arrangement, on impinged surfaces are reported. The experiments were conducted with four different jet-to-jet distances (S/. D= 2, 4, 6 and 8) at the constant nozzle-to-plate distance of L/. D= 4. The swirling jets with the swirl numbers of 0.4 were associated with twisted tapes. The multiple conventional impinging jets (M- CIJs) were also tested, for comparison. The flow patterns on an impinged surface were visualized using oil film technique while the distributions of temperature field and Nusselt number on impinged surface were evaluated via a thermochromic liquid crystal (TLC) sheet coupled with image processing technique. The experimental results showed that the M- SIJs offered higher heat transfer rate on impinged surfaces than the M- CIJs of all jet-to-jet distances (S/. D). © 2011 Elsevier Ltd.

Wattanasakulpong N.,Mahanakorn University of Technology | Ungbhakorn V.,Chulalongkorn University
Computational Materials Science | Year: 2013

The objective of the present paper is to investigate the bending, buckling and vibration behaviors of carbon nanotube-reinforced composite (CNTRC) beams. The beams resting on the Pasternak elastic foundation, including a shear layer and Winkler spring, are considered. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are estimated by using the rule of mixture. Various shear deformation theories are employed to deal with the problems. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of bending, buckling and vibration analyses of CNTRC beams based on several higher-order shear deformation theories are presented and discussed in details. Several aspects of beam types, spring constant factors, carbon nanotube volume fraction, etc., are taken into investigation. © 2013 Elsevier B.V. All rights reserved.

Mansawat W.,Chulalongkorn University | Vilaivan C.,Chulalongkorn University | Balazs A.,University Paris - Sud | Aitken D.J.,University Paris - Sud | Vilaivan T.,Chulalongkorn University
Organic Letters | Year: 2012

The effect of ring size of four- to six-membered cyclic β-amino acid on the hybridization properties of pyrrolidinyl peptide nucleic acid with an alternating α/β peptide backbone is reported. The cyclobutane derivatives (acbcPNA) show the highest T m and excellent specificity with cDNA and RNA. © 2012 American Chemical Society.

Eab C.H.,Chulalongkorn University | Lim S.C.,Multimedia University
Journal of Physics A: Mathematical and Theoretical | Year: 2012

In this paper, Gaussian models of retarded and accelerated anomalous diffusion are considered. Stochastic differential equations of fractional order driven by single or multiple fractional Gaussian noise terms are introduced to describe retarding and accelerating subdiffusion and superdiffusion. Short- and long-time asymptotic limits of the mean-squared displacement of the stochastic processes associated with the solutions of these equations are studied. Specific cases of these equations are shown to provide possible descriptions of retarding or accelerating anomalous diffusion. © 2012 IOP Publishing Ltd.

Ungbhakorn V.,Chulalongkorn University | Wattanasakulpong N.,Mahanakorn University of Technology
Applied Acoustics | Year: 2013

Thermo-elastic vibration response of functionally graded (FG) plates carrying distributed patch mass is investigated in this paper based on third order shear deformation theory. The solutions are obtained by energy method. It is assumed that the volume fraction of material constituents varies across the plate thickness according to the power law distribution. Three different types of temperature rise throughout the plate thickness; namely, uniform, linear and nonlinear temperature rises; are used to derive the frequency results. The characteristics of free vibration as influenced by plate thickness ratios, plate aspect ratios, the power law index, material properties and shear deformation are discussed. Some available frequency results associated with FG plates without the patch mass are used to validate the present results. The new frequency results of the functionally graded plates with distributed patch mass are also presented in this paper. The effects of magnitude, size and location of the patch mass on free vibratory frequencies are investigated. In addition, forced vibration analysis with external dynamic load acting on the sub-domain of the patch mass is also presented and discussed. © 2013 Elsevier Ltd.All rights reserved.

Wattanasakulpong N.,Mahanakorn University of Technology | Ungbhakorn V.,Chulalongkorn University
Aerospace Science and Technology | Year: 2014

Linear and nonlinear vibration problems of elastically end restrained beams made of functionally graded materials (FGMs) are investigated in this present paper. Due to porosities, possibly occurring inside FGMs during fabrication, it is therefore necessary to consider the vibration behavior of beams having porosities in this investigation. The rule of mixture is modified to describe and approximate material properties of the functionally graded beams with porosity phases. The differential transformation method (DTM) is employed to solve linear and nonlinear vibration responses of FGM beams with different kinds of elastic supports. The effects of material property distribution, spring constants and porosity volume fraction on linear and nonlinear frequencies of FGM beams are also presented and discussed in detail. © 2013 Elsevier Masson SAS.

Morris G.,Tir Na Nog | Morris G.,Chulalongkorn University | Maes M.,Chulalongkorn University | Maes M.,Deakin University
BMC Medicine | Year: 2013

Background: 'Encephalomyelitis disseminata' (multiple sclerosis) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are both classified as diseases of the central nervous system by the World Health Organization. This review aims to compare the phenomenological and neuroimmune characteristics of MS with those of ME/CFS.Discussion: There are remarkable phenomenological and neuroimmune overlaps between both disorders. Patients with ME/CFS and MS both experience severe levels of disabling fatigue and a worsening of symptoms following exercise and resort to energy conservation strategies in an attempt to meet the energy demands of day-to-day living. Debilitating autonomic symptoms, diminished cardiac responses to exercise, orthostatic intolerance and postural hypotension are experienced by patients with both illnesses. Both disorders show a relapsing-remitting or progressive course, while infections and psychosocial stress play a large part in worsening of fatigue symptoms. Activated immunoinflammatory, oxidative and nitrosative (O+NS) pathways and autoimmunity occur in both illnesses. The consequences of O+NS damage to self-epitopes is evidenced by the almost bewildering and almost identical array of autoantibodies formed against damaged epitopes seen in both illnesses. Mitochondrial dysfunctions, including lowered levels of ATP, decreased phosphocreatine synthesis and impaired oxidative phosphorylation, are heavily involved in the pathophysiology of both MS and ME/CFS. The findings produced by neuroimaging techniques are quite similar in both illnesses and show decreased cerebral blood flow, atrophy, gray matter reduction, white matter hyperintensities, increased cerebral lactate and choline signaling and lowered acetyl-aspartate levels.Summary: This review shows that there are neuroimmune similarities between MS and ME/CFS. This further substantiates the view that ME/CFS is a neuroimmune illness and that patients with MS are immunologically primed to develop symptoms of ME/CFS. © 2013 Morris and Maes; licensee BioMed Central Ltd.

Lundgren J.D.,Copenhagen University | Babiker A.G.,University College London | Gordin F.,George Washington University | Emery S.,University of New South Wales | And 15 more authors.
New England Journal of Medicine | Year: 2015

Background Data from randomized trials are lacking on the benefits and risks of initiating antiretroviral therapy in patients with asymptomatic human immunodeficiency virus (HIV) infection who have a CD4+ count of more than 350 cells per cubic millimeter. Methods We randomly assigned HIV-positive adults who had a CD4+ count of more than 500 cells per cubic millimeter to start antiretroviral therapy immediately (immediate-initiation group) or to defer it until the CD4+ count decreased to 350 cells per cubic millimeter or until the development of the acquired immunodeficiency syndrome (AIDS) or another condition that dictated the use of antiretroviral therapy (deferred-initiation group). The primary composite end point was any serious AIDS-related event, serious non-AIDS-related event, or death from any cause. Results A total of 4685 patients were followed for a mean of 3.0 years. At study entry, the median HIV viral load was 12,759 copies per milliliter, and the median CD4+ count was 651 cells per cubic millimeter. On May 15, 2015, on the basis of an interim analysis, the data and safety monitoring board determined that the study question had been answered and recommended that patients in the deferred-initiation group be offered antiretroviral therapy. The primary end point occurred in 42 patients in the immediate-initiation group (1.8%; 0.60 events per 100 personyears), as compared with 96 patients in the deferred-initiation group (4.1%; 1.38 events per 100 person-years), for a hazard ratio of 0.43 (95% confidence interval [CI], 0.30 to 0.62; P<0.001). Hazard ratios for serious AIDS-related and serious non-AIDS-related events were 0.28 (95% CI, 0.15 to 0.50; P<0.001) and 0.61 (95% CI, 0.38 to 0.97; P = 0.04), respectively. More than two thirds of the primary end points (68%) occurred in patients with a CD4+ count of more than 500 cells per cubic millimeter. The risks of a grade 4 event were similar in the two groups, as were the risks of unscheduled hospital admissions. Conclusions The initiation of antiretroviral therapy in HIV-positive adults with a CD4+ count of more than 500 cells per cubic millimeter provided net benefits over starting such therapy in patients after the CD4+ count had declined to 350 cells per cubic millimeter. Copyright © 2015 Massachusetts Medical Society.

Phasukarratchai N.,Chulalongkorn University | Tontayakom V.,The Innovation Company | Tongcumpou C.,Chulalongkorn University
Biomass and Bioenergy | Year: 2012

Phorbol esters (PEs), a compound group found in Jatropha curcas seeds, are toxic and thermal-resistant compounds; thus, the further application of Jatropha pressed seed is limited to use only as soil amendment, even though the meal has high protein content, similarly to that of soy bean meal. This study introduces a technique to remove PEs from Jatropha meal using a surfactant aqueous-based solution. Both single and mixed surfactant systems were evaluated. The Hydrophile-lipophile Balance (HLB) of a nonionic surfactant was found to be related to its PEs removal efficiency. The average initial level of PEs in the mechanically-pressed meals was 1.45 mg g -1. The five systems used to reduce the mass fraction of PEs were as follows: water; 40 mmol L -1 polyoxyethylene (20) sorbitan monooleate (Tween 80); mixed of 40 mmol L -1 Tween 80, 5 mmol L -1 sodium bis (ethylhexyl) sulfosuccinate (AOT), and 100 mmol L -1 NaCl; 40 mmol L -1 fatty alcohol C12-14 extended with 9 ethoxylates (Dehydol LS9); and mixed of 40 mmol L -1 Dehydol LS9, 5 mmol L -1 AOT, and 100 mmol L -1 NaCl; these systems removed 22.49%, 81.43%, 81.23%, 81.87%, and 78.85% from the initial meal, respectively. The optimal extraction time was 15 min, and the removal of PEs was enhanced by the application of a double extraction procedure. This technique is promising because mass fraction of the PEs was reduced from the initial meal almost 90%; this approaches the level of PEs found almost as low as those found in a non-toxic variety of Jatropha seed. © 2012 Elsevier Ltd.

Chaiyapinunt S.,Chulalongkorn University | Khamporn N.,Siam University
Solar Energy | Year: 2013

This paper presents a study of thermal performance for a glass window with a curved venetian blind installed on the indoor side in terms of heat gain in the shortwave part of radiation. The curved venetian blind, whose optical properties are considered nonspecular, is modeled as an effective layer. The mathematical model of the combined glass window and venetian blind is developed by combining the mathematical model of glass window and the mathematical model of a curved venetian blind using the matrix layer calculation method. The experiment is performed in a test room to measure the heat gain due to solar radiation passing through the glass window with a curved venetian blind installed in the shortwave part of radiation. The predicted results from the developed model are compared with the experimental results. The agreement between the predicted results and the experimental results is good. From the study it is found that installing a curved venetian blind to the glass window causes a significant reduction in heat gain compared to the plain glass window. The heat gain through the glass window with blind in the shortwave part of radiation (solar heat gain coefficient in the shortwave part of radiation (ShW SHGC)) is analyzed. It is found that the ShW SHGC is mainly affected by the slat properties, slat angle and solar profile angle. The glass window using blind with a lower value of slat reflectance, will have a smaller value of ShW SHGC. The slat distance also affects the ShW SHGC. The glass window using blind with a lower value of slat distance has a lower value of ShW SHGC. The effect of the slat curvature on the ShW SHGC is small when compared to the effect of other parameters. The effects of the investigated parameters on the ShW SHGC for diffuse radiation are similar to the effects on the ShW SHGC for direct radiation. When installing blind to different kinds of glass window other than clear glass window, it is found that the thermal performance is similar to the case of clear glass window. The magnitude of the ShW SHGC for the glass window with blind is also dependent on the optical properties of the glass window used. The glass window with blind using a lower value of the glass transmittance has a lower value of the ShW SHGC. The absorptance of the glass window has direct effect on the solar heat gain coefficient in the longwave part of radiation (LoW SHGC). © 2013 Elsevier Ltd.

Eab C.H.,Chulalongkorn University | Lim S.C.,Multimedia University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

Distributed-order fractional Langevin-like equations are introduced and applied to describe anomalous diffusion without unique diffusion or scaling exponent. It is shown that these fractional Langevin equations of distributed order can be used to model the kinetics of retarding subdiffusion whose scaling exponent decreases with time and the strongly anomalous ultraslow diffusion with mean square displacement which varies asymptotically as a power of logarithm of time. © 2011 American Physical Society.

Suppavorasatit I.,Chulalongkorn University | Cadwallader K.R.,University of Illinois at Urbana - Champaign
Journal of Agricultural and Food Chemistry | Year: 2012

The effect of the enzymatic deamidation by protein-glutaminase (PG) on flavor-binding properties of soy protein isolate (SPI) under aqueous conditions was evaluated by a modified equilibrium dialysis (ultrafiltration) technique. Binding parameters, such as number of binding sites (n) and binding constants (K), were derived from Klotz plots. The partial deamidation of SPI by PG (43.7% degree of deamidation) decreased overall flavor-binding affinity (nK) at 25 °C for both vanillin and maltol by approximately 9- and 4-fold, respectively. The thermodynamic parameters of binding indicated that the flavor-protein interactions were spontaneous (negative ΔG°) and that the driving force of the interactions shifted from entropy to enthalpy driven as a result of deamidation. Deamidation of soy protein caused a change in the mechanism of binding from hydrophobic interactions or covalent bonding (Schiff base formation) to weaker van der Waals forces or hydrogen bonding. © 2012 American Chemical Society.

Morris G.,Tir Na Nog | Maes M.,Chulalongkorn University | Maes M.,Deakin University
Current Neuropharmacology | Year: 2014

Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) has been classified as a disease of the central nervous system by the WHO since 1969. Many patients carrying this diagnosis do demonstrate an almost bewildering array of biological abnormalities particularly the presence of oxidative and nitrosative stress (O&NS) and a chronically activated innate immune system. The proposal made herein is that once generated chronically activated O&NS and immune-inflammatory pathways conspire to generate a multitude of self-sustaining and self-amplifying pathological processes which are associated with the onset of ME/CFS. Sources of continuous activation of O&NS and immune-inflammatory pathways in ME/CFS are chronic, intermittent and opportunistic infections, bacterial translocation, autoimmune responses, mitochondrial dysfunctions, activation of the Toll-Like Receptor Radical Cycle, and decreased antioxidant levels. Consequences of chronically activated O&NS and immune-inflammatory pathways in ME/CFS are brain disorders, including neuroinflammation and brain hypometabolism/hypoperfusion, toxic effects of nitric oxide and peroxynitrite, lipid peroxidation and oxidative damage to DNA, secondary autoimmune responses directed against disrupted lipid membrane components and proteins, mitochondrial dysfunctions with a disruption of energy metabolism (e.g. compromised ATP production) and dysfunctional intracellular signaling pathways. The interplay between all of these factors leads to self-amplifying feed forward loops causing a chronic state of activated O&NS, immune-inflammatory and autoimmune pathways which may sustain the disease. © 2014 Bentham Science Publishers.

News Article | March 2, 2017

“Everybody has a plan until they get punched in the mouth,” said Boxer Mike Tyson once while talking about his opponents’ prefight tactics. What Tyson said is relevant for startups also as most of them fail to survive the first connect with customers. “How to prepare for that ‘punch’ which can make or break your dream”, is a million dollar question for any startup. To answer it, Thailand’s most prestigious institution for higher education, Chulalongkorn University, and YoStartups, which provides early stage support to build and scale start-ups, joined hands and ran a unique startup acceleration programme in the university’s innovation hub. Based on the concept of ‘lean Startup’, this two-day and one-night event, called CU Startup Weekend, on February 4 and 5, 2017 taught the participants how the power of failure provides a proper perspective of success. Professor Bundhit Eua-arporn, President, Chulalongkorn University, inaugurated the event. Professors, alumni and existing students attended workshops and lectures, which emphasized the need to test a startup idea among its potential users and customers before it becomes a final product. The process of successive failure helps create a minimum viable product and maximizes its chances of success. Government in Thailand is already working on an economic supercharger, Thailand 4.0, the purpose of which is to develop the country as a high-income nation. “With Thailand 4.0, our country is on the path to becoming an innovation-led economy that works on the principle of more for less. Through such workshops, Chulalongkorn University and its resources are being channelized to help Thai entrepreneurs unleash their real potential to build world-class high growth organisations from Thailand, says Dr Natcha Thawesaengskulthai, Assistant to the President for Strategy and Innovation at Chulalongkorn University. Various reports suggest that 75% to 90% startups fail because of several factors, prominent among them is the failure to come us as a viable product. The initial startup idea is a fiction or a dream. The concept of ‘lean startup’ advocates testing of this initial dream with customer engagement at every stage from translating into a business plan to manufacturing a final product. As per Jappreet Sethi, Co Founder of, “The biggest risk a startup faces is the initial failure. The concept looks nice at the ideation stage or on paper but remember, that’s just the first stage. “He adds, “So it’s better to put the concept into the domain of potential customers, so that you will know its pros and cons and by the time it comes on paper, it’s through the first stage.” Sethi says that regular feedback from customers help arrive at a minimum viable product which has great success rates. The workshop activities include helping participants refine their concept, solidify their startup ideas and business models, create entrepreneurial mind-sets, enhance their viability through business workshops and readiness level in term of business maturity, presentation, communication skill, and mindset. The Jury comprised of YoStartups team that included Sotiris Yannopoulos from Greece, Abhishek Singh and Jappreet Sethi from India. Frank Fan, Head of Asia at Euroterra Capital flew down from Hong Kong and DR. Naphunsakorn Waiyawuththanapoom, from Chula Innovation Hub. After hours of mind-boggling relentless interactions and exchange of ideas with all the participants, three startups, HealthCheck and Tixget were selected for further mentoring and training by the YoStartups and CU Innovation hub. Co-founded by Pakawat Teerawattanasuk and Chanchai Tanatkatrakul, is a chat-as-a-service company targeting enterprise customers to provide automated 24/7 customer service / support center via instant messaging platforms that are efficient and affordable. The second winner was Healthcheck, the first online health checkup booking agency, which was born out of enterprising initiatives of three entrepreneurs, Ms. Aurachorn Inkanuwat, Dr Itthikorn Thosuwanchote and Dr Pipat Duangkamsawat. It introduced a convenient system for any person seeking medical assistance to book any health checkup program at any hospitals, anytime in the most convenient manner. A four-member team of Baramee Navanopparatskul, Peter Thaveepolcharoen, Pawoot Pongvitayapanu, Premthana Thepibool introduced 'tixget', which emerged as the third winner. 'tixget' is an online ticket marketplace platform for tours and traveling activities. Both business groups and customers can benefit from it. While the travelers can buy their tickets online, tour operators and companies can manage their ticket sale using its software as a solution. ---------------------- CU Innovation Hub supports Thai society to become an intellectual community with an innovation ecosystem that links expertise, research, and innovation with creativity skill, critical thinking, and entrepreneurship. Our three major activities include Academy, Incubation and Acceleration, and Outreach or innovation one-stop- service CU Innovation Hub focuses on grooming talents, nurturing innovations and sustaining Thailand’s start-ups. We act as a platform to help transform how Thais live, learn, and play, leading to the foundation of sustainable economic and social development. YoStartups is vibrant, energetic and focused Company supporting startups from the idea stage onwards, guiding them to success. It does this through a team of talented and experienced professionals from all over the world, utilizing a unique web platform that provides content management, investor readiness & beta customers. Moreover, startups can rely on our team for one to one mentoring, best startup practices and technics to solve the vast majority of issues for pre seed and also seeded startups. YoStartups collaborates with leading Universities, co-working spaces, incubators, VC’s & Business Angels for a holistic approach in the startup competitive and uncertain environment. Since, according to all recent International studies indicate that 3 out of 4 startups unfortunately fail, YoStartups is the answer to make peoples dreams a reality in this fast changing world full of inequality. For more information please contact:

Kraiwattanawong K.,King Mongkut's University of Technology Thonburi | Tamon H.,Kyoto University | Praserthdam P.,Chulalongkorn University
Microporous and Mesoporous Materials | Year: 2011

Carbon cryogels are dried by 3 days of freeze drying with 6 h of pre-freezing whereas the carbon xerogels are prepared by 1 day of subcritical drying in the selective range of synthesis condition, but the mesoporosity of carbon xerogels are not well controlled. This research is to study the influence of solvent species in the solvent exchange for the preparation of carbon xerogels cooperated by the evaporation drying and the vacuum drying. The good solvent for the high mesoporous properties of carbon xerogels is desirable in the wide range of synthesis condition. The carbon xerogels prepared from resorcinol and formaldehyde were characterized by the nitrogen adsorption apparatus and the field emission scanning electron microscope (FE-SEM). The results illustrate that the mesoporous carbon xerogels in the two subcritical dryings can be easily prepared by solvent exchange. Among the solvents, t-butanol allows the great results in the preparation of high mesoporous carbon xerogels and is well applied in the wide range of synthesis conditions. The FE-SEM images elucidate that the carbon xerogels dried by the vacuum drying contain the particles interconnection larger than the evaporation drying. © 2010 Elsevier Inc. All rights reserved.

Kaewpengkrow P.,Chulalongkorn University | Atong D.,National Metal and Materials Technology Center | Sricharoenchaikul V.,Chulalongkorn University
Renewable Energy | Year: 2014

Catalytic upgrading of the pyrolytic vapors after fast pyrolysis of Jatropha residue was performed using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) at 673-873K. The Py-GC/MS analyses for pyrolysis vapors show a range of aromatic hydrocarbons, hydrocarbon compounds, phenols, alcohols, aldehydes, ketones, acids and esters, furan and N-containing compounds. The result showed that high temperature had positive influence on the yields of pyrolytic products. Catalytic testing was performed by using Al2O3, ZrO2 based catalysts and their modified ones with impregnation of Pd, Ru, and Ni, respectively. The Al2O3 and ZrO2 were impregnated with CeO2 to promote metal dispersion prior to deposition of Pd, Ru, or Ni. From the experiment, these catalysts showed some potential to convert the highly oxygenated compounds to aromatic and hydrocarbons. The hydrocarbon yields increased withincreasing catalyst to Jatropha ratio in all catalysts. The hydrocarbon selectivity was Ni-Ce/Al2O3>Al2O3>Ce/Al2O3>Pd-Ce/Al2O3>Ru-Ce/Al2O3 in Jatropha to catalyst ratio of 1:5. Pd-Ce/Al2O3 was the most effective in terms of increased aromatic and hydrocarbon compounds, decreased oxygenated and N-compounds. Though Al2O3 increased favorable aromatic and hydrocarbon compounds with completely elimination of acid but it also promoted adverse N-containing compounds. Activities of Ru-Ce/Al2O3 were similar to Ce/Al2O3 except for the selectivity towardacid compounds. Comparing to ZrO2 catalysts, all Al2O3 based catalysts displayed relatively higher activity towarddeoxygenation reactions which resulted in low quantity of carboxylic acids and other oxygenated compounds while enhanced yields of aliphatic and aromatic hydrocarbons. Al2O3 had surface area of 103.38m2/g while surface area of ZrO2 was 12m2/g, indicating that catalyst with high surface area had better catalytic activity. However, Al2O3 catalysts seemed to promote N-compounds suggesting that further denitrogenation is required while pyrolysis with ZrO2 had disadvantage on high yield of acid which could cause the corrosion problem. Nevertheless, overall performances of these two support catalysts are acceptable and can be considered as good candidates for bio-oil upgrading catalysts. © 2013 Elsevier Ltd.

Vichaphund S.,Chulalongkorn University | Aht-ong D.,Chulalongkorn University | Sricharoenchaikul V.,Chulalongkorn University | Atong D.,National Metal and Materials Technology Center
Renewable Energy | Year: 2014

HZSM-5 with high surface area of 625m2/g was successfully synthesized by hydrothermal method at 160°C for 72h. The metal promoted on HZSM-5 catalyst was prepared by liquid ion exchange method. From XRD results, the addition of metals such as Co and Ni did not change the HZSM-5 structure. The metal/HZSM-5 showed lower crystallinity and surface area than the parent HZSM-5 because of the metal dispersion on the HZSM-5 surface. The metal contents of Co/HZSM-5 and Ni/HZSM-5 detected by EDX were less than 1wt%. Catalytic fast pyrolysis of Jatropha waste using HZSM-5 and metals/HZSM-5 was investigated in terms of biomass to catalyst ratios (1:0, 1:1, 1:5 and 1:10) and types of metals (Co and Ni). From the results, it can be concluded that both biomass to catalyst ratios and the presence of metals had an effect on the increase in aromatic hydrocarbons yields as well as the decrease in the oxygenated and N-containing compounds. Both Co/HZSM-5 and Ni/HZSM-5 promoted the production of aliphatic compounds. Additionally, the PAHs compounds such as napthalenes and indenes, which caused the formation of coke, could be inhibited by metal/HZSM-5, particularly, Ni/HZSM-5. Among catalysts, Ni/HZSM-5 showed the highest hydrocarbon yield of 97.55% with N-containing compounds remained only 1.78%. The formation of hydrocarbon compounds increased the heating values of bio-oils while the elimination of the undesirable oxygenated compounds such as acids and ketones could alleviate problem regarding acidity and instability in bio oils. © 2013 Elsevier Ltd.

Chareonlimkun A.,King Mongkut's University of Technology Thonburi | Champreda V.,National Center for Genetic Engineering and Biotechnology | Shotipruk A.,Chulalongkorn University | Laosiripojana N.,King Mongkut's University of Technology Thonburi
Bioresource Technology | Year: 2010

The simultaneous hydrolysis/dehydration reaction of sugarcane bagasse, rice husk and corncob was studied under hot compressed water in the presence of TiO2, ZrO2 and TiO2-ZrO2 at 473-673 K. Among them, the reaction of corncob at 573 K in the presence of TiO2-ZrO2 produced the highest furfural and 5-hydroxymethylfurfural (HMF) yields (10.3% and 8.6%) with less by-products (i.e. glucose, fructose, xylose, and 1,6-anhydroglucose) selectivities. It was found that the catalyst preparation procedure and calcination temperature strongly affected its reactivity. Catalysts prepared by (co-) precipitation method gained higher reactivity than those prepared by sol-gel and physical mixing methods. The suitable calcination temperature for TiO2 and ZrO2 was at 773 K, whereas that for TiO2-ZrO2 was at 873 K; the XRD patterns revealed that different portions of phase formation were observed over catalysts with different calcination temperature. The portion of these phase formations affected the acidity-basicity of catalyst and thus the catalyst reactivity. © 2010 Elsevier Ltd. All rights reserved.

Kaewpengkrow P.,Chulalongkorn University | Atong D.,National Metal and Materials Technology Center | Sricharoenchaikul V.,Chulalongkorn University
Bioresource Technology | Year: 2014

The objective of this study was to catalytically upgrade bio-oil from organic vapors of Jatropha wastes using Py-GC/MS. Catalytic testing included Al2O3, ZrO2, TiO2 (rutile, T1) and TiO2 (anatase, T2) supporter catalysts modified with transition metals (Pd, Ru or Ni) by impregnation method. In non-catalytic runs, the main vapor products were fatty acids (60.74%). With the presence of Al2O3 based catalysts, carboxylic acids were obviously reduced to 0.76-19.61% while hydrocarbons were the main products (42.00-64.06%). Comparing among four supporters, total hydrocarbon yields increased with presence of all catalysts. Higher yields were obtained by T2>Al2O3>CA>NiCA>RuCA catalysts. Al2O3 and T2 supports were the most effective for increased hydrocarbons while decreased oxygenated compounds (15%) which is one of the primary aims of this study. The result indicating that high surface area resulted in better catalytic activity but also adversely promoted N-compounds. Therefore these catalysts can be applied to improve properties of pyrolytic products. © 2014 Elsevier Ltd.

Jatupaiboon N.,Chulalongkorn University | Pan-Ngum S.,Chulalongkorn University | Israsena P.,National Electronics and Computer Technology Center
The Scientific World Journal | Year: 2013

We propose to use real-time EEG signal to classify happy and unhappy emotions elicited by pictures and classical music. We use PSD as a feature and SVM as a classifier. The average accuracies of subject-dependent model and subject-independent model are approximately 75.62% and 65.12%, respectively. Considering each pair of channels, temporal pair of channels (T7 and T8) gives a better result than the other area. Considering different frequency bands, high-frequency bands (Beta and Gamma) give a better result than low-frequency bands. Considering different time durations for emotion elicitation, that result from 30 seconds does not have significant difference compared with the result from 60 seconds. From all of these results, we implement real-time EEG-based happiness detection system using only one pair of channels. Furthermore, we develop games based on the happiness detection system to help user recognize and control the happiness. © 2013 Noppadon Jatupaiboon et al.

Sunsaneewitayakul B.,Chulalongkorn University | Yao Y.,Peking Union Medical College | Thamaree S.,Naresuan University | Zhang S.,Chulalongkorn University
Journal of Cardiovascular Electrophysiology | Year: 2012

Endocardial Mapping and Ablation of Brugada Syndrome. Introduction: Brugada syndrome (BS) is characterized by ST-segment elevation in the right precordial electrocardiogram (ECG) leads and episodes of ventricular fibrillation (VF). This study aimed to observe the feasibility of substrate modification by radiofrequency catheter ablation and its effects on VF storm. Methods and Results: Ten BS patients (all men; median age 36.5 years) with VF storm (group I, n = 4) and no VF storm (group II, n = 6) were enrolled in the study between August 2007 and December 2008. All patients underwent electrophysiological study using noncontact mapping. The multielectrode array was placed in the right ventricular outflow tract (RVOT). The isopotential map was analyzed during sinus rhythm and the region that had electrical activity occurring during J point to +60 (J+60) milliseconds interval of the V1 or V2 of surface ECG was considered as the late activation zone (LAZ) and also the substrate for ablation. LAZ was found in RVOT with variable distribution in both groups. Endocardial catheter ablation of the LAZ modified Brugada ECG pattern in 3 of 4 patients (75%) and suppressed VF storm in all 4 patients in group I during long-term follow-up (12-30 months). One patient had complete right bundle branch block from the ablation procedure. Conclusions: LAZ on RVOT identified by noncontact mapping may serve as potential VF substrate in BS patients with VF episodes. Radiofrequency ablation on LAZ normalized ECG, suppressed VF storm, and reduced VF recurrence. The procedure is safe and may prevent VF occurrence.

Kasemsiri P.,Chulalongkorn University | Hiziroglu S.,Oklahoma State University | Rimdusit S.,Chulalongkorn University
Composites Part A: Applied Science and Manufacturing | Year: 2011

In this study, properties of experimentally manufactured wood polymer composites based on benzoxazine resin (BA-a) and cashew nut shell liquid (CNSL) copolymer were investigated. Specimens having as high as 75% by weight of eastern redcedar (Juniperus virginiana L.) particles mixed with BA-a/CNSL matrix were manufactured for property evaluation. From the experimental results, wood particles evidently lowered the curing temperature and activation energy of the BA-a/CNSL curing process. Thermal and mechanical properties of the samples were found to substantially increase with increasing amount of wood particles. Dimensional stability in a form of the thickness swelling of the specimens and overall surface quality from water immersion test were found to be comparable with those of other wood-based composite panels. © 2011 Elsevier Ltd. All rights reserved.

Ratanakamnuan U.,Chulalongkorn University | Atong D.,National Metal and Materials Technology Center | Aht-Ong D.,Chulalongkorn University
Carbohydrate Polymers | Year: 2012

The esterification of cellulose from waste cotton fabric in a N,N-dimethylacetamide/lithium chloride solvent system was carried out using different types of fatty acid chloride including butyryl chloride, capryloyl chloride, and lauroyl chloride as esterifying agents, and N,N-dimethyl 1-4-aminopyridine as a catalyst under conventional and microwave activation. Microwave esterification was performed under 2.45 GHz with power varying from 90 to 450 W. The optimum conditions for esterification of cotton cellulose with various esterifying agents were investigated in terms of reaction time and temperature to attain appropriate %weight increase and degree of substitution of esterified-cellulose. The degree of substitution, functional group and chemical structure, and thermal stability of cellulose ester powder were characterized by 1H NMR, FTIR, and TGA/SDTA analysis. Morphologies, crystallinity, and solubility of modified cellulose by two different heating methods were compared. © 2011 Elsevier Ltd. All Rights Reserved.

Chunhacha P.,Pharmaceutical Technology International Program | Pongrakhananon V.,Chulalongkorn University | Rojanasakul Y.,West Virginia University | Chanvorachote P.,Chulalongkorn University
American Journal of Physiology - Cell Physiology | Year: 2012

Both caveolin-1 (Cav-1) and Mcl-1 have been implicated in the regulation of cancer cell anoikis, but their relationship and underlying mechanisms of regulation are not known. The present study demonstrated for the first time that Cav-1 regulates Mcl-1 through protein-protein interaction and inhibits its down regulation during cell anoikis in human lung cancer cells. Immunoprecipitation and immunocyto-chemistry studies showed that Cav-1 interacted with Mcl-1 and prevented it from degradation via the ubiquitin-proteasome pathway. Mcl-1 and Mcl-1-Cav-1 complex were highly elevated in Cav-1-overexpressing cells but were greatly reduced in Cav-1 knockdown cells. Consistent with this finding, we found that Mcl-1 ubiquitination was significantly attenuated by Cav-1 over expression but increased by Cav-1 knockdown. Together, our results indicate a novel role of Cav-1 in anoikis regulation through Mcl-1 interaction and stabilization, which provides a new insight to the pathogenesis of metastatic lung cancer and its potential treatment. © 2012 the American Physiological Society.

Sriromreun P.,Thammasat University | Petchsuk A.,National Metal and Materials Technology Center | Opaprakasit M.,Chulalongkorn University | Opaprakasit P.,Thammasat University
Polymer Degradation and Stability | Year: 2013

Aliphatic/aromatic copolyesters, which possess good mechanical property and degradability, are of immense interest. Standard characterization techniques for the copolymer structure and degradation behaviors have been developed. The techniques are applied to examine hydrolytic degradation of poly(ethylene terephthalate-co-lactic acid) in a phosphate buffer solution (pH 7.2) at 60°C. The weight loss of the copolymer and pH of the medium as a function of time are examined. 1H NMR spectra provide information on microstructure and molecular weight of the samples, where deviations of the results from the actual values are observed, due to low solubility of the copolymer. More accurate results are obtained from TGA and FTIR experiments, as the samples are characterized in bulk. Insight into degradation mechanisms of the copolymer is derived from FTIR spectra. The content of aromatic esters in the soluble degraded species is determined from UV-Vis spectroscopy. These standard methods can be applied to various types of degradable aliphatic/aromatic copolyesters, which are essential in property assessment and determination of their potential applications. © 2012 Elsevier Ltd. All rights reserved.

Rattanarat P.,Chulalongkorn University | Rattanarat P.,Colorado State University | Dungchai W.,King Mongkut's University of Technology Thonburi | Cate D.,Colorado State University | And 3 more authors.
Analytical Chemistry | Year: 2014

The release of metals and metal-containing compounds into the environment is a growing concern in developed and developing countries, as human exposure to metals is associated with adverse health effects in virtually every organ system. Unfortunately, quantifying metals in the environment is expensive; analysis costs using certified laboratories typically exceed $100/sample, making the routine analysis of toxic metals cost-prohibitive for applications such as occupational exposure or environmental protection. Here, we report on a simple, inexpensive technology with the potential to render toxic metals detection accessible for both the developing and developed world that combines colorimetric and electrochemical microfluidic paper-based analytical devices (mPAD) in a three-dimensional configuration. Unlike previous mPADs designed for measuring metals, the device reported here separates colorimetric detection on one layer from electrochemical detection on a different layer. Separate detection layers allows different chemistries to be applied to a single sample on the same device. To demonstrate the effectiveness of this approach, colorimetric detection is shown for Ni, Fe, Cu, and Cr and electrochemical detection for Pb and Cd. Detection limits as low as 0.12 μg (Cr) were achieved on the colorimetric layer while detection limits as low as 0.25 ng (Cd and Pb) were achieved on the electrochemical layer. Selectivity for the target analytes was demonstrated for common interferences. As an example of the device utility, particulate metals collected on air sampling filters were analyzed. Levels measured with the mPAD matched known values for the certified reference samples of collected particulate matter. © 2014 American Chemical Society.

Boonrattanakij N.,Chulalongkorn University | Lu M.-C.,Chia Nan University of Pharmacy and Science | Anotai J.,King Mongkut's University of Technology Thonburi
Water Research | Year: 2011

The mechanisms of iron precipitation and crystallization in a fluidized-bed reactor were investigated. Within the typical Fenton's reagent dosage and pH range, ferric ions as a product from ferrous ion oxidation would be supersaturated and would subsequently precipitate out in the form of ferric hydroxide after the initiation of the Fenton reaction. These precipitates would simultaneously crystallize onto solid particles in a fluidized-bed Fenton reactor if the precipitation proceeded toward heterogeneous nucleation. The heterogeneous crystallization rate was controlled by the fluidized material type and the aging/ripening period of the crystallites. Iron crystallization onto the construction sand was faster than onto SiO 2, although the iron removal efficiencies at 180 min, which was principally controlled by iron hydroxide solubility, were comparable. To achieve a high iron removal rate, fluidized materials have to be present at the beginning of the Fenton reaction. Organic intermediates that can form ferro-complexes, particularly volatile fatty acids, can significantly increase ferric ion solubility, hence reducing the crystallization performance. Therefore, the fluidized-bed Fenton process will achieve exceptional performance with respect to both organic pollutant removal and iron removal if it is operated with the goal of complete mineralization. Crystallized iron on the fluidized media could slightly retard the successive crystallization rate; thus, it is necessary to continuously replace a portion of the iron-coated bed with fresh media to maintain iron removal performance. The iron-coated construction sand also had a catalytic property, though was less than those of commercial goethite. © 2011 Elsevier Ltd.

Piyawattanametha W.,National Electronics and Computer Technology Center | Piyawattanametha W.,Chulalongkorn University | Piyawattanametha W.,Stanford University | Wang T.D.,University of Michigan
IEEE Journal on Selected Topics in Quantum Electronics | Year: 2010

In this paper, we demonstrate a miniature, near-infrared microscope (λ= 785 nm) that uses a novel dual-axes confocal architecture. Scalability is achieved with postobjective scanning, and a microelectromechanical systems mirror provide real-time (>4 Hz) in vivo imaging. This instrument can achieve subcellular resolution with deep tissue penetration and large field of view. An endoscope-compatible version can image digestive tract epithelium to guide tissue biopsy and monitor therapy. © 2010 IEEE.

Papong S.,National Metal and Materials Technology Center | Malakul P.,National Metal and Materials Technology Center | Malakul P.,Chulalongkorn University
Bioresource Technology | Year: 2010

In this study, the life-cycle energy and environmental assessment was conducted for bioethanol production from cassava in Thailand. The scope covered all stages in the life cycle of bioethanol production including cultivating, chip processing, transportation and bioethanol conversion. The input-output data were collected at plantation sites and ethanol plants which included materials usage, energy consumption, and all emissions. From the energy analysis, the results show that cassava-based bioethanol has a negative net energy value with an energy ratio was less than 1, indicating a net energy loss. For the environmental performance, the results show that throughout the life cycle of bioethanol, the conversion stage contributes most to the environmental impacts which is due to the use of coal for power and steam production in the bioethanol plants. It is suggested that a partial substitution of coal with biogas produced from existing wastewater treatment could lead to a significant reduction in the environmental impact. © 2009 Elsevier Ltd. All rights reserved.

Songjaroen T.,Chulalongkorn University | Dungchai W.,King Mongkut's University of Technology Thonburi | Chailapakul O.,Chulalongkorn University | Henry C.S.,Colorado State University | Laiwattanapaisal W.,Chulalongkorn University
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2012

A microfluidic paper-based analytical device (μPAD) for the separation of blood plasma from whole blood is described. The device can separate plasma from whole blood and quantify plasma proteins in a single step. The μPAD was fabricated using the wax dipping method, and the final device was composed of a blood separation membrane combined with patterned Whatman No.1 paper. Blood separation membranes, LF1, MF1, VF1 and VF2 were tested for blood separation on the μPAD. The LF1 membrane was found to be the most suitable for blood separations when fabricating the μPAD by wax dipping. For blood separation, the blood cells (both red and white) were trapped on blood separation membrane allowing pure plasma to flow to the detection zone by capillary force. The LF1-μPAD was shown to be functional with human whole blood of 24-55% hematocrit without dilution, and effectively separated blood cells from plasma within 2 min when blood volumes of between 15-22 μL were added to the device. Microscopy was used to confirm that the device isolated plasma with high purity with no blood cells or cell hemolysis in the detection zone. The efficiency of blood separation on the μPAD was studied by plasma protein detection using the bromocresol green (BCG) colorimetric assay. The results revealed that protein detection on the μPAD was not significantly different from the conventional method (p > 0.05, pair t-test). The colorimetric measurement reproducibility on the μPAD was 2.62% (n = 10) and 5.84% (n = 30) for within-day and between day precision, respectively. Our proposed blood separation on μPAD has the potential for reducing turnaround time, sample volume, sample preparation and detection processes for clinical diagnosis and point-of care testing. This journal is © 2012 The Royal Society of Chemistry.

Laosiripojana N.,King Mongkut's University of Technology Thonburi | Charojrochkul S.,National Metal and Materials Technology Center | Kim-Lohsoontorn P.,Mahidol University | Assabumrungrat S.,Chulalongkorn University
Journal of Catalysis | Year: 2010

The activity of nanoscale CeO2 and doped CeO2 (with Gd, Y, Nb, La, and Sm) toward the steam reforming of CH4 in the presence of H2S was investigated for later application as an in-stack reforming catalyst in a solid oxide fuel cell. Although H2S is commonly known as a poisonous gas for metallic-based catalysts, it was found that the presence of appropriate H2S content increases the reforming activity of these CeO2-based catalysts. According to postreaction catalyst characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, temperature-programmed desorption, H2/H2O + H2S titration, and 18O/16O isotope exchange, it was revealed that this behavior is related to the formation of various Ce-O-S phases (Ce(SO 4)2, Ce2(SO4)3, and Ce2O2S) during the reaction. Our studies indicated that the formation of Ce(SO4)2 promotes the oxygen storage capacity, the lattice oxygen mobility, and eventually the reforming activity, whereas the formation of Ce2O2S oppositely reduces both properties and lowers the reforming rate. © 2010 Elsevier Inc. All rights reserved.

Arpornwichanop A.,Chulalongkorn University | Patcharavorachot Y.,King Mongkut's University of Technology Thonburi
Chemical Engineering Research and Design | Year: 2013

This study presents a performance analysis of a proton-conducting SOFC (SOFC-H+) with internal reforming of methane. The autothermal reforming within the SOFC-H+ stack is considered to be a potential solution of the carbon formation problem facing in operation of internal steam reforming SOFC-H+. A one-dimensional, steady-state model of the SOFC-H+ coupled with a detailed electrochemical model is employed to investigate its performance in terms of power density and fuel cell efficiency. The simulation results show that when SOFC-H+ is operated under an autothermal reforming environment, the presence of carbon monoxide, which is a major cause of carbon formation, in the fuel cell stack decreases. Effect of key operating parameters, such as temperature, steam-to-carbon and oxygen-to-carbon feed ratios, current density and fuel utilization, on the SOFC-H+ performance in terms of electrical efficiencies and energy demand is also investigated. The results indicate that operating temperatures have strong influence on SOFC-H+ performance, carbon monoxide production and heat generation. © 2013 The Institution of Chemical Engineers.

Laosiripojana N.,King Mongkut's University of Technology Thonburi | Assabumrungrat S.,Chulalongkorn University
Applied Catalysis B: Environmental | Year: 2011

Synthesized nano-scale CeO2 enables to convert poisonous methanethiol (CH3SH) to hydrogen-rich gas via the solid-gas reaction between CeO2 and CH3SH under sufficient condition. In the presence of H2O, the phase of Ce(SO4)2 occurs from the reaction and offers high CH3SH reforming activity. In contrast, without H2O adding, Ce2O2S is formed instead and results in low catalyst activity. Further catalyst improvement was performed by coating this synthesized nano-scale CeO2 over cylindrical-shape Rh/Al2O3 pellet (as called CeO2-coated Rh/Al2O3). This developed catalyst was found to enhance good activity, stability, and reusability (over 5 reaction cycles; 72h) for converting CH3SH to hydrogen-rich gas with high hydrogen yield achievement. For more practical application, this catalyst was also tested over olefin offgas containing CH3SH and ethanethiol (CH3SCH3) from an olefin manufacturing; and was found to efficiently convert this offgas to hydrogen-rich gas without sulfur present in the product gas under a proper regeneration time. This result highlights a great benefit of CeO2-coated Rh/Al2O3 for integrating the clean energy generation with toxic-waste treatment, which offers significant energy and environmental benefits. © 2010 Elsevier B.V.

Limparyoon N.,Chulalongkorn University | Seetapan N.,National Metal and Materials Technology Center | Kiatkamjornwong S.,Chulalongkorn University
Polymer Degradation and Stability | Year: 2011

Acrylamide (AM) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS-H +) or its sodium salt (AMPS-Na+) were copolymerised by free-radical crosslinking polymerization to obtain poly(AM-co-AMPS-H +) and poly(AM-co-AMPS-Na+) superabsorbent polymers (SAPs). A maximum water absorbency in deionised water of 1200 g g-1 was achieved for poly(AM-co-AMPS-Na+) at a 85% mol of AMPS-Na +. The inclusion of mica at 5-30% (w w-1) into the preparation of poly(AM-co-AMPS-Na+) SAP leads to an intercalated structure, as detected by XRD and TEM analyses. Poly(AM-co-AMPS-Na +)/30% (w w-1) mica SAP nanocomposite showed a tap water absorbency of 593 g g-1 with a better thermal stability, compared to the pure SAP. Cone calorimetric analyses revealed that the wood specimens coated with the prepared poly(AM-co-AMPS-Na+) SAP or its 30% (w w -1) mica nanocomposite provided excellent protection in delaying the ignition time after exposure to an open flame when compared to that observed with the uncoated specimen. The maximum reduction in the peak heat release rate and the greatest extension of time at peak heat release rate were observed with the nanocomposite-coated surface, but the total heat release rate was increased. The delayed burning mechanism is brought by the intercalating structure of mica in the SAP nanocomposites, which provided a better shielding effect against external heat sources, and the capability of the SAP nanocomposite in holding a large amount of water. © 2011 Elsevier Ltd. All rights reserved.

Yoosuk B.,National Metal and Materials Technology Center | Tumnantong D.,Chulalongkorn University | Prasassarakich P.,Chulalongkorn University
Fuel | Year: 2012

Unsupported sulfide catalysts are a potentially promising approach towards furthering the understanding and development of a better heterogeneous catalytic system capable of performing the hydrodeoxygenation (HDO) of bio-oil proficiently under mild and short reaction conditions and times, respectively. Amorphous unsupported Ni-Mo sulfide, prepared from ammonium tetrathiomolybdate (ATTM) by a one step hydrothermal method, is already sulfided and so does not need a sulfidation step. The addition of the Ni promoter prevents the growth of Mo sulfide particles and causes a reduction in the surface area and a change in the pore characteristics as the amount of added Ni was increased. Ni sulfide alone (no Mo) showed a completely different morphology and properties compared to those of the Mo-containing sulfides, with or without the copresence of Ni. The activity and selectivity of catalysts was investigated using phenol as a model substrate in the direct-deoxygenation (DDO) and hydrogenation (HYD) reactions in a HDO system. The Ni-Mo sulfide catalyst with optimal Ni amount had a significantly higher phenol conversion efficiency (96.2 mol%), and favored a HYD pathway, than that seen for the Mo sulfide one (71.0 mol%) that favored a DDO pathway. H2-temperature programmed desorption (TPD) suggested that this synergy was mainly derived from a change in the quality and not the number of the active sites. The synergetic effect was a function of the stoichiometric composition with the maximum synergetic effect being obtained at a Ni/(Mo + Ni) ratio of 0.3. This could result from the high dispersion of the active species and the generation of a more active Ni-Mo-S phase. © 2011 Elsevier Ltd. All rights reserved.

Kasemsiri P.,Chulalongkorn University | Hiziroglu S.,Oklahoma State University | Rimdusit S.,Chulalongkorn University
Journal of Materials Processing Technology | Year: 2012

The objective of the study is to investigate the influence of heat treatment on shrinkage, density, surface roughness, water absorption, diffusion coefficient, swelling and shear strength of eastern redcedar (Juniperus virginiana L.) samples. The anatomical structures of samples are also observed by scanning electron microscope (SEM). Specimens are exposed to temperature levels of 120 °C, 160 °C and 190 °C for time spans of 2 and 8 h. Based on the results of this study, dimensional stability in the form of shrinkage of the samples is improved by 2.68%, 1.40% and 1.49% for tangential, longitudinal and radial grain orientations as function of heat treatment, respectively. Heat treatment also enhances surface quality of the samples based on numerical values determined from stylus type of equipment. Water absorption, swelling values and diffusion coefficient of the samples are also reduced with heat treatment. Samples exposed to heat treatment have lower shear strength values, ranging from 25.12% to 52.67%, than those of control samples. It appears that all properties evaluated in this work are affected more pronouncedly as temperature and exposure time is increased. © 2012 Elsevier B.V. All rights reserved.

Seetapan N.,National Metal and Materials Technology Center | Limparyoon N.,Chulalongkorn University | Kiatkamjornwong S.,Chulalongkorn University
Polymer Degradation and Stability | Year: 2011

Poly[acrylamide-co-(2-acrylamido-2-methylpropane sodium sulfonate)] superabsorbents and superabsorbent composites (SAPCs) with zinc borate and/or melamine as fire retardants were synthesized. Water absorbencies decreased inversely to added amount of fire retardant. Thermal stability of SAPC/zinc borate increases with increasing zinc borate. Incorporating melamine improved thermal stability of the SAPC until 300 °C. Flammability analysis demonstrated that wood surface coated with SAP or SAPC emulsions extended time to ignition of the wood. Peak heat release rate and total heat release are smallest in specimens coated with SAPC/30% melamine. Wood coated with SAPC incorporating 20% zinc borate/10% melamine mixture gave the longest time to ignition at 4 min. © 2011 Elsevier Ltd. All rights reserved.

Moeller H.B.,University of Aarhus | Aroankins T.S.,University of Aarhus | Slengerik-Hansen J.,University of Aarhus | Pisitkun T.,University of Aarhus | And 2 more authors.
Journal of Cell Science | Year: 2014

The post-translational modifications (PTMs) phosphorylation and ubiquitylation regulate plasma membrane protein function. Here, we examine the interplay between phosphorylation and ubiquitylation of the membrane protein aquaporin-2 (AQP2) and demonstrate that phosphorylation can override the previously suggested dominant endocytic signal of K63-linked polyubiquitylation. In polarized epithelial cells, although S256 is an important phosphorylation site for AQP2 membrane localization, the rate of AQP2 endocytosis was reduced by prolonging phosphorylation specifically at S269. Despite their close proximity, AQP2 phosphorylation at S269 and ubiquitylation at K270 can occur in parallel, with increased S269 phosphorylation and decreased AQP2 endocytosis occurring when K270 polyubiquitylation levels are maximal. In vivo studies support this data, with maximal levels of AQP2 ubiquitylation occurring in parallel to maximal S269 phosphorylation and enhanced AQP2 plasma membrane localization. In conclusion, we demonstrate for the first time that although K63-linked polyubiquitylation marks AQP2 for endocytosis, site-specific phosphorylation can counteract polyubiquitylation to determine its final localization. Similar mechanisms might exist for other plasma membrane proteins. © 2014. Published by The Company of Biologists Ltd.

Khemthongcharoen N.,National Electronics and Computer Technology Center | Jolivot R.,National Electronics and Computer Technology Center | Rattanavarin S.,National Electronics and Computer Technology Center | Piyawattanametha W.,National Electronics and Computer Technology Center | Piyawattanametha W.,Chulalongkorn University
Advanced Drug Delivery Reviews | Year: 2014

A new chapter in the history of medical diagnosis happened when the first X-ray technology was invented in the late 1800s. Since then, many non-invasive and minimally invasive imaging techniques have been invented for clinical diagnosis to research in cellular biology, drug discovery, and disease monitoring. These imaging modalities have leveraged the benefits of significant advances in computer, electronics, and information technology and, more recently, targeted molecular imaging. The development of targeted contrast agents such as fluorescent and nanoparticle probes coupled with optical imaging techniques has made it possible to selectively view specific biological events and processes in both in vivo and ex vivo systems with great sensitivity and selectivity. Thus, the combination of targeted molecular imaging probes and optical imaging techniques have become a mainstay in modern medicinal and biological research. Many promising results have demonstrated great potentials to translate to clinical applications. In this review, we describe a discussion of employing imaging probes and optical microendoscopic imaging techniques for cancer diagnosis. © 2013 Elsevier B.V.

Cohen C.J.,Community Research Initiative of New England | Andrade-Villanueva J.,University of Guadalajara | Clotet B.,Autonomous University of Barcelona | Fourie J.,Dr urie Medical Center | And 8 more authors.
The Lancet | Year: 2011

Background The non-nucleoside reverse transcriptase inhibitor (NNRTI), rilpivirine (TMC278; Tibotec Pharmaceuticals, County Cork, Ireland), had equivalent sustained efficacy to efavirenz in a phase 2b trial in treatment-naive patients infected with HIV-1, but fewer adverse events. We aimed to assess non-inferiority of rilpivirine to efavirenz in a phase 3 trial with common background nucleoside or nucleotide reverse transcriptase inhibitors (N[t]RTIs). Methods We undertook a 96-week, phase 3, randomised, double-blind, double-dummy, non-inferiority trial in 98 hospitals or medical centres in 21 countries. We enrolled adults (≥18 years) not previously given antiretroviral therapy and with a screening plasma viral load of 5000 copies per mL or more and viral sensitivity to background N(t)RTIs. We randomly allocated patients (1:1) using a computer-generated interactive web-response system to receive oral rilpivirine 25 mg once daily or efavirenz 600 mg once daily; all patients received an investigator-selected regimen of background N(t)RTIs (tenofovir-disoproxil-fumarate plus emtricitabine, zidovudine plus lamivudine, or abacavir plus lamivudine). The primary outcome was non-inferiority (12 margin on logistic regression analysis) at 48 weeks in terms of confirmed response (viral load <50 copies per mL, defined by the intent-to-treat time to loss of virologic response [TLOVR] algorithm) in all patients who received at least one dose of study drug. This study is registered with, number NCT00543725. Findings From May 22, 2008, we screened 947 patients and enrolled 340 to each group. 86 of patients (291 of 340) who received at least one dose of rilpivirine responded, compared with 82 of patients (276 of 338) who received at least one dose of efavirenz (difference 3·5 [95 CI -1·7 to 8·8]; pnon-inferiority<0·0001). Increases in CD4 cell counts were much the same between groups. 7 of patients (24 of 340) receiving rilpivirine had a virological failure compared with 5 of patients (18 of 338) receiving efavirenz. 4 of patients (15) in the rilpivirine group and 7 (25) in the efavirenz group discontinued treatment due to adverse events. Grade 2-4 treatment-related adverse events were less common with rilpivirine (16 [54 patients]) than they were with efavirenz (31 [104]; p<0·0001), as were rash and dizziness (p<0·0001 for both) and increases in lipid levels were significantly lower with rilpivirine than they were with efavirenz (p<0·0001). Interpretation Despite a slightly increased incidence of virological failures, a favourable safety profile and non-inferior efficacy compared with efavirenz means that rilpivirine could be a new treatment option for treatment-naive patients infected with HIV-1. Funding Tibotec. © 2011 Elsevier Ltd.

Chareonlimkun A.,King Mongkut's University of Technology Thonburi | Champreda V.,National Center for Genetic Engineering and Biotechnology | Shotipruk A.,Chulalongkorn University | Laosiripojana N.,King Mongkut's University of Technology Thonburi
Fuel | Year: 2010

The benefit of TiO2, ZrO2 and SO4-ZrO 2 on the reactions of C5-sugar (xylose), C 6-sugar (glucose), cellulose, and lignocellulose was studied in hot compressed water (HCW) at 473-673 K with an aim to produce furfural and 5-hydroxymethylfurfural (HMF). TiO2 and SO4-ZrO 2 were found to active for hydrolysis and dehydration reactions producing high furfural and HMF yields with less by-products (i.e. glucose, fructose, xylose, and 1,6-anhydroglucose (AHG)) formation, whereas ZrO 2 was highly active for isomerization reaction; thus significant amount of fructose was observed in the liquid product. Importantly, it was also found that the starting salt precursor, the sulfur-doping content (for SO 4-ZrO2) and the calcination temperature strongly affected the catalyst reactivity. Catalysts prepared from the chloride-based precursors (i.e. ZrOCl2 and TiCl4) gained higher reactivity compared to those prepared from nitrate-based precursors (i.e. ZrO(NO3) 2 and TiO(NO3)2) due to their greater acidity, according to the NH3- and CO2-TPD studies. For SO 4-ZrO2, among the catalyst with sulfur contents of 0.75%, 1.8% and 2.5%, SO4-ZrO2 with 1.8% sulfur content presented the highest acidity and reactivity toward hydrolysis and dehydration reactions. It is noted that the suitable calcination temperature for all catalysts was at 773 K; the XRD patterns revealed that different portions of phase formation was observed over catalysts with different calcination temperatures i.e. anatase/rutile for TiO2 and monoclinic/tetragonal for ZrO2 and SO4-ZrO2; the portion of these phase formations obviously affected the acidity-basicity of catalyst and thus the catalyst reactivity. © 2009 Elsevier Ltd. All rights reserved.

Treeprasertsuk S.,Chulalongkorn University | Bjornsson E.,Reykjavik University | Enders F.,Biostatistics and Health science Research | Suwanwalaikorn S.,Chulalongkorn University | Lindor K.D.,Arizona State University
World Journal of Gastroenterology | Year: 2013

AIM: To study whether the severity of liver fibrosis estimated by the nonalcoholic fatty liver disease (NAFLD) fibrosis score can predict all-cause mortality, cardiac complications, and/or liver complications of patients with NAFLD over long-term follow-up. METHODS: A cohort of well-characterized patients with NAFLD diagnosed during the period of 1980-2000 was identified through the Rochester Epidemiology Project. The NAFLD fibrosis score (NFS) was used to separate NAFLD patients with and without advanced liver fibrosis. We used the NFS score to classify the probability of fibrosis as < -1.5 for low probability, > -1.5 to < 0.67 for intermediate probability, and > 0.67 for high probability. Primary endpoints included allcause death and cardiovascular- and/or liver-related mortality. From the 479 patients with NAFLD assessed, 302 patients (63%) greater than 18 years old were included. All patients were followed, and medical charts were reviewed until August 31, 2009 or the date when the first primary endpoint occurred. By using a standardized case record form, we recorded a detailed history and physical examination and the use of statins and metformin during the follow-up period. RESULTS: A total of 302/479 (63%) NAFLD patients (mean age: 47 ± 13 year) were included with a followup period of 12.0 ± 3.9 year. A low probability of advanced fibrosis (NFS < -1.5 at baseline) was found in 181 patients (60%), while an intermediate or high probability of advanced fibrosis (NSF > -1.5) was found in 121 patients (40%). At the end of the follow-up period, 55 patients (18%) developed primary endpoints. A total of 39 patients (13%) died during the follow-up. The leading causes of death were non-hepatic malignancy (n = 13/39; 33.3%), coronary heart disease (CHD) (n = 8/39; 20.5%), and liver-related mortality (n = 5/39; 12.8%). Thirty patients had new-onset CHD, whereas 8 of 30 patients (27%) died from CHD-related causes during the follow-up. In a multivariate analysis, a higher NFS at baseline and the presence of new-onset CHD were significantly predictive of death (OR = 2.6 and 9.2, respectively; P < 0.0001). Our study showed a significant, graded relationship between the NFS, as classified into 3 subgroups (low, intermediate and high probability of liver fibrosis), and the occurrence of primary endpoints. The use of metformin or simvastatin for at least 3 mo during the follow-up was associated with fewer deaths in patients with NAFLD (OR = 0.2 and 0.03, respectively; P < 0.05). Additionally, the rate of annual NFS change in patients with an intermediate or high probability of advanced liver fibrosis was significantly lower than those patients with a low probability of advanced liver fibrosis (0.06 vs 0.09, P = 0.004). The annual NFS change in patients who died was significantly higher than those in patients who survived (0.14 vs 0.07, P = 0.03). At the end of the follow-up, we classified the patients into 3 subgroups according to the progression pattern of liver fibrosis by comparing the NFS at baseline to the NFS at the end of the followup period. Most patients were in the stable-fibrosis (60%) and progressive-fibrosis (37%) groups, whereas only 3% were in the regressive fibrosis. CONCLUSION: A higher NAFLD fibrosis score at baseline and a new onset of CHD were significantly predictive of death in patients with NAFLD. © 2013 Baishideng. All rights reserved.

Apilux A.,Japan Advanced Institute of Science and Technology | Apilux A.,Chulalongkorn University | Ukita Y.,Japan Advanced Institute of Science and Technology | Chikae M.,Japan Advanced Institute of Science and Technology | And 2 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2013

To the best of our knowledge, this is the first report on paper-based devices for automating the sequential multistep procedures of a sandwich-type enzyme-linked immunosorbent assay (ELISA) that require only a single-step application of the sample solution. The device was based on a piece of nitrocellulose (NC) membrane with specially designed channels, where all the reagents are applied at different locations in order to control the fluid travel to the detection region. The inkjet printing method, a simple and low-cost process, was used to create the flow channel and device barrier patterns. The fabricated barrier was found to be an efficient boundary for the liquid along the printed design in the NC membrane, enabling direct control of the reagent flow time. ELISA results were obtained with a single-step sample application. The developed devices (so-called automated paper-based devices) provided a simple procedure for the sandwich ELISA, while reducing assay time and reagent consumption. Colorimetric results were measured using digital camera imaging with software processing. The capability of the method developed herein was successfully used to determine the levels of human chorionic gonadotropin (hCG) by ELISA. © The Royal Society of Chemistry.

Ratnarathorn N.,King Mongkut's University of Technology Thonburi | Chailapakul O.,Chulalongkorn University | Henry C.S.,Colorado State University | Dungchai W.,King Mongkut's University of Technology Thonburi
Talanta | Year: 2012

The first investigation of silver nanoparticle (AgNP) colorimetric sensing of Cu 2 by paper-based analytical devices (PADs) is reported here. AgNP colorimetric sensing for the detection of Cu 2 was first characterized by UV-visible spectroscopy. The -SH groups on homocysteine (Hcy) and dithiothreitol (DTT) were used to modify the AgNP surface whereas the -COOH and -NH 2 functional groups have strong affinity to Cu 2 relative to other ions in solution. The plasmon resonance absorption peak intensity at 404 nm decreased and a new red-shifted band at 502 nm occurred in the presence of Cu 2. Paper devices coated with the modified AgNP solution changed from yellow to orange and green-brown color after the addition of Cu 2 due to nanoparticle aggregation. The color intensity change as a function of Cu 2 concentration gave a linear response in the range of 7.8-62.8 μM (R 2=0.992). The limit of naked-eye detection is 7.8 nM or 0.5 μg L -1. A color change observed by the naked eye with the addition of Cu 2 can be clearly differentiated from the other metals (As 3, Cd 2, Co 2, Hg 2, Ni 2, Pb 2, Zn 2, Mg 2, Mn 2, Ca 2, Fe 3, Na, and K) at 15.7 μM. The use of different flow directions in the PADs and μPADs for Cu 2 detection was also demonstrated. Levels of Cu 2 in real water samples were measured using the paper devices to be 2.9±0.24 μM (tap water) and 3.2±0.30 μM (pond water), respectively, and were within error of the values measured using an atomic absorption spectrometer (2.8±0.08 μM in tap water, and 3.4±0.04 μM in pond water). Thus, this work shows the successful integration of paper devices and AgNP colorimetric sensing as a simple, rapid, easy-to-use, inexpensive and portable alternative point-of-measurement monitoring. © 2012 Elsevier B.V.

Saiyood S.,Mahidol University | Vangnai A.S.,Chulalongkorn University | Thiravetyan P.,King Mongkut's University of Technology Thonburi | Inthorn D.,Mahidol University
Journal of Hazardous Materials | Year: 2010

Dracaena sanderiana and Dracaena fragrans plants, as representatives of native, tropical, evergreen plants with fibrous root systems, were evaluated for bisphenol A (BPA) tolerance and uptake capability. D. sanderiana demonstrated significantly higher BPA removal capability than D. fragrans. Therefore, it was chosen for further study. D. sanderiana tolerated BPA toxicity levels up to 80μM, while higher BPA concentrations damaged the plant. In the sterile hydroponic system with an initial BPA concentration of 20μM, the plant could uptake approximately 50% of the BPA. The plant's ability to translocate BPA was confirmed by the detection of BPA that accumulated at the roots and stems, but not at the leaves of the plant. Upon BPA exposure, the D. sanderiana secreted extracellular plant mucilage as a protective barrier to the toxic compound. In the non-sterile treatment, the BPA dissipation was contributed not only by the D. sanderiana plant, but also by the co-existing microbes. The BPA reached 85% of the initial concentration at 20μM. Among the six plant-associating bacterial isolates, Bacillus cereus strain BPW4 and Enterobacter sp. strain BPW5 colonized the D. sanderiana root surface and facilitated BPA dissipation in the hydroponic treatment system. In addition, the success of the BPA treatment in the hazardous waste landfill leachate demonstrated the potential application of D. sanderiana plant in the phytoremediation of BPA contaminated wastewater or industrial leachate. © 2010 Elsevier B.V.

Authayanun S.,Chulalongkorn University | Wiyaratn W.,King Mongkut's University of Technology Thonburi | Assabumrungrat S.,Chulalongkorn University | Arpornwichanop A.,Chulalongkorn University
Fuel | Year: 2013

The aim of this study is to theoretically analyze the performance and efficiency of a glycerol processing and high-temperature proton exchange membrane fuel cell (HT-PEMFC) integrated system. Glycerol is considered a renewable fuel source for hydrogen production. In comparison with methane, glycerol shows a better performance in terms of high hydrogen production and low possibility to carbon formation. However, the content of CO2 in the reformate gas and its dilution effect as well as the energy required for the glycerol processor should be concerned. When considering the operation of the glycerol processor for HT-PEMFCs, the reformer temperature (TR) has a significant influence on hydrogen content in the reformate gas, whereas the steam-to-carbon ratio (S/C) affects hydrogen production slightly. In addition, the content of CO in the reformate gas satisfies the required constraint for HT-PEMFC operation. The performance and efficiency of the glycerol reforming process and HT-PEMFCs integrated system are evaluated by considering a heat recovery and a water balance. © 2012 Elsevier Ltd. All rights reserved.

Songjaroen T.,Chulalongkorn University | Dungchai W.,King Mongkut's University of Technology Thonburi | Chailapakul O.,Chulalongkorn University | Laiwattanapaisal W.,Chulalongkorn University
Talanta | Year: 2011

Paper-based microfluidic devices are an alternative technology for fabricating simple, low-cost, portable and disposable platforms for clinical diagnosis. Hereby, a novel wax dipping method for fabricating paper-based microfluidic devices (μPADs) is reported. The iron mould for wax dipping was created by a laser cutting technique. The designed pattern was transferred onto paper by dipping an assembly mould into melted wax. The optimal melting temperature and dipping time were investigated. The optimal melting temperature was in the range of 120-130 °C, and the optimal dipping time was 1 s. The whole fabrication process could be finished within 1 min without the use of complicated instruments or organic solvents. The smallest hydrophilic channel that could be created by the wax dipping method was 639 ± 7 μm in size. The reproducibility of the μPAD fabrication for hydrophilic channel width of the test zone and sample zone was 1.48% and 6.30%, respectively. To verify the performance of the μPAD, multiple colorimetric assays for simultaneous detection of glucose and protein in real samples were performed. An enzymatic assay and the bromocresol green (BCG) method were conducted on the paper device to determine the presence of glucose and protein in a test solution. The results of the assays were not significantly different from those of the conventional methods (p > 0.05, pair t-test and one-way ANOVA method). The wax dipping provides a new alternative method for fabricating lab-on-paper devices for multiple clinical diagnostics and will be very beneficial for developing countries. © 2011 Elsevier B.V. All rights reserved.

Rattanarat P.,Chulalongkorn University | Dungchai W.,King Mongkut's University of Technology Thonburi | Siangproh W.,Srinakharinwirot University | Chailapakul O.,Chulalongkorn University | Henry C.S.,Colorado State University
Analytica Chimica Acta | Year: 2012

We report the development of an electrochemical paper-based analytical device (ePAD) for the selective determination of dopamine (DA) in model serum sample. The ePAD device consists of three layers. In the top layer, SU-8 photoresist defines a hydrophilic sample application spot on the filter paper. The middle layer was made from transparency film and contained two holes, one for sample preconcentration and the other for the surfactant to allow transfer to the third layer. A screen-printed carbon electrode formed the bottom layer and was used for electrochemical measurements. In the absence of the anionic surfactant, sodium dodecyl sulfate (SDS), the oxidation peaks of DA, ascorbic acid (AA) and uric acid (UA) overlapped. With the addition of SDS, the DA oxidation peak shifted to more negative values and was clearly distinguishable from AA and UA. The oxidation potential shift was presumably due to preferential electrostatic interactions between the cationic DA and the anionic SDS. Indeed, whilst the SDS-modified paper improved the DA current five-fold, the non-ionic Tween-20 and cationic tetradecyltrimethylammonium bromide surfactants had no effect or reduced the current, respectively. Furthermore, only the SDS-modified paper showed the selective shift in oxidation potential for DA. DA determination was carried out using square-wave voltammetry between -0.2 and 0.8. V vs. Ag/AgCl, and this ePAD was able to detect DA over a linear range of 1-100μM with a detection limit (S/N = 3) of 0.37μM. The ePAD seems suitable as a low cost, easy-to-use, portable device for the selective quantitation of DA in human serum samples. © 2012 Elsevier B.V..

Nuttavuthisit K.,Chulalongkorn University | Thogersen J.,University of Aarhus
Journal of Business Ethics | Year: 2015

Consumer trust is a key prerequisite for establishing a market for credence goods, such as “green” products, especially when they are premium priced. This article reports research on exactly how, and how much, trust influences consumer decisions to buy new green products. It identifies consumer trust as a distinct volition factor influencing the likelihood that consumers will act on green intentions and strongly emphasizes the needs to manage consumer trust as a prerequisite for the development of a market for green products. Specifically, based on a mixture of qualitative and quantitative methods, it is found that lack of consumer trust is a barrier for the development of a market for organic food in Thailand. Two focus groups and ten in-depth interviews revealed low knowledge about and low trust in organic food, certification, control, and labeling. Further, a mall-intercept survey (N = 177) revealed that lack of (especially) system trust reduces consumer expectations about benefits of buying organic food, and it makes them less likely to buy organic food. Mistrust in the control system and in the authenticity of food sold as organic has a significant negative impact on self-reported buying behavior. Implications for policy and future research are discussed. © 2015 Springer Science+Business Media Dordrecht

Pukrushpan P.,Chulalongkorn University | Tulvatana W.,Chulalongkorn University | Pittayapongpat R.,Queen Sirikit National Institute of Child Health
Journal of AAPOS | Year: 2014

We report the clinical and pathological findings of a rare case of congenital uveal melanoma. A 7-week-old girl presented with history of a black area at the inner corner of her left eye since birth. Examination revealed an enlarged globe with an area of visible uveal pigment nasal to the cornea, an iris mass, and shallow anterior chamber in the left eye. Magnetic resonance imaging revealed an intraocular mass. Enucleation was performed when the girl was 2 months of age. Pathologic examination confirmed a malignant melanoma epithelioid cell type with extraocular extension. She was treated with chemotherapy and subtotal exenteration.

Chontanawat J.,King Mongkut's University of Technology Thonburi | Wiboonchutikula P.,Chulalongkorn University | Buddhivanich A.,King Mongkut's University of Technology Thonburi
Energy | Year: 2014

The study computes and analyses the sources of the change of energy intensity of the manufacturing industries in Thailand during the period (1991-2011) using the decomposition method. The Logarithmic Mean Divisia Index is computed and the results show that the energy intensity in the period (1991-2000) increased greatly from the increased energy intensity of each industry. In the more recent period (2000-2011) the energy intensity declined a little. However the decline was mainly from the structural change effect with negligible contribution from decreased energy intensity of each industry. The findings imply the need to balance industrial restructuring policies with efforts to reduce energy intensity for a sustainable economic development. Besides, there is much room for individual industries to improve their energy efficiency. Policies on restructuring energy prices and other non-price related measures should be devised to induce individual industries, particularly the highly energy intensive ones, to reduce their energy intensity. © 2014 Elsevier Ltd.

Sricharoenchaikula V.,Chulalongkorn University | Atongb D.,National Metal and Materials Technology Center
Energy Procedia | Year: 2012

Greater usage of biodiesel worldwide results in significant generation of glycerol waste from transesterification process of plant oil. In the work reported here, thermal conversion of biodiesel manufacturing wastes including extracted physic nut and palm shell mixed with glycerol waste was carried out using a tubular reactor at 700-900°C. Studied parameters were reaction temperature, ratio of each wastes, air factor and residence time. Mixed wastes were first pelletized to cylindrical shape of 2 mm diameter and 3 mm height before feeding into the reaction vessel at the feeding rate of 5 g/min. Air and nitrogen were used as reacting and carrier gases, respectively. Product gases contained mainly of CO, CO 2, H 2, CH 4 were continuously measured by dedicated online TCD/NDIR analyzer.Results indicated that as reaction temperature increased, CO 2 decreased while yields of CO, CH 4 and H 2 increased. Greater conversion to CO 2, CO, H 2 occurred with air factor increased from 0.0 to 0.3. Further increase in air factor resulted in lesser CO and H 2 from greater competing combustion reactions. CH 4 decreased when air factor changed from 0.0 to 0.6. The maximum gas LHV's are 3.48 MJ/m 3 and 2.27 MJ/m 3 for glycerol waste mixed with physic nut waste and palm shell waste, respectively. The maximum of mole ratio of H 2 to CO obtained is 0.59 for physic nut and 0.37 for palm shell mixed wastes. These findings showed that products from co-gasification of mixed wastes from biodiesel production may be used for power generation or further upgraded to produce value added fuel product which would significantly improve the economics of this waste-to-energy process. © 2011 Published by Elsevier Ltd.

Rongwong W.,King Mongkut's University of Technology Thonburi | Assabumrungrat S.,Chulalongkorn University | Jiraratananon R.,King Mongkut's University of Technology Thonburi
Journal of Membrane Science | Year: 2013

This work presents a rate based model to estimate the performance of CO2 absorption by monoethanolamine (MEA) solution using a hollow fiber membrane contactor. The predicted CO2 fluxes were validated with the experimental data of both polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) membranes from the literature. The simulation results of the PTFE membrane showed that the CO2 flux could be predicted by the rate based model with a deviation less than 4% for a non-wetted mode of operation. For the PVDF membrane, the model predicted the CO2 fluxes fairly well under partially-wetted mode of operation. The simulated concentration profiles in both the gas and liquid phases, as well as the liquid temperature profile of PTFE membrane, corresponded well with the experimental data. A study of parameter sensitivity analysis revealed that the proposed model is most sensitive to Henry's constant and when the reaction regime between CO2 and MEA changes from intermediate fast-instantaneous to instantaneous, when the membrane is 20% wetted. A comparison between the CO2 fluxes of the non-wetted and partially wetted modes showed that the increase of CO2 flux in the non-wetted mode with an increasing gas composition and liquid temperature is more significant than that of the partially wetted mode. © 2012 Elsevier B.V.

Patarakul K.,Chulalongkorn University | Lo M.,Monash University | Adler B.,Monash University
BMC Microbiology | Year: 2010

Background: Leptospirosis is a zoonosis of worldwide distribution caused by infection with pathogenic serovars of Leptospira spp. The most common species, L. interrogans, can survive in the environment for lengthy periods of time in between infection of mammalian hosts. Transmission of pathogenic Leptospira to humans mostly occurs through abraded skin or mucosal surfaces after direct or indirect contact with infected animals or contaminated soil or water. The spirochete then spreads hematogenously, resulting in multi-organ failure and death in severe cases. Previous DNA microarray studies have identified differentially expressed genes required for adaptation to temperature and osmolarity conditions inside the host compared to those of the environment. Results. In order to identify genes involved in survival in the early spirochetemic phase of infection, we performed a transcriptional analysis of L. interrogans serovar Copenhageni upon exposure to serum in comparison with EMJH medium. One hundred and sixty-eight genes were found to be differentially expressed, of which 55 were up-regulated and 113 were down-regulated. Genes of known or predicted function accounted for 54.5 and 45.1% of up- and down-regulated genes, respectively. Most of the differentially expressed genes were predicted to be involved in transcriptional regulation, translational process, two-component signal transduction systems, cell or membrane biogenesis, and metabolic pathways. Conclusions. Our study showed global transcriptional changes of pathogenic Leptospira upon exposure to serum, representing a specific host environmental cue present in the bloodstream. The presence of serum led to a distinct pattern of gene expression in comparison to those of previous single-stimulus microarray studies on the effect of temperature and osmolarity upshift. The results provide insights into the pathogenesis of leptospirosis during the early bacteremic phase of infection. © 2010 Patarakul et al; licensee BioMed Central Ltd.

Boonchom B.,King Mongkut's University of Technology Thonburi | Puttawong S.,Chulalongkorn University
Physica B: Condensed Matter | Year: 2010

The thermal decomposition kinetics of FePO4·2H2O in dynamical air atmosphere was studied by mean TG-DTG-DTA. The stage and product of the thermal decomposition were determined. A number of kinetic models and calculation procedures were used to determine the kinetic triplet and thermodynamic parameters characterizing the dehydration process. The obtained activation energy and most kinetic model indicate the single kinetic mechanism and three-dimension diffusion as "Ginstling-Brounstein equation (D4 model)", respectively. The thermodynamic functions (ΔH*, ΔG* and ΔS*) of the dehydration reaction are calculated by the activated complex theory and indicate that the process is non-spontaneous without connecting with the introduction of heat. The kinetic and thermodynamic results were satisfactory which present good correlation with a linear correlation coefficient close to unit a low standard deviation. © 2010 Elsevier B.V. All rights reserved.

Kijrungphaiboon W.,Chulalongkorn University | Chantarasriwong O.,King Mongkut's University of Technology Thonburi | Chavasiri W.,Chulalongkorn University
Tetrahedron Letters | Year: 2012

Cl 3CCN/PPh 3 and CBr 4/PPh 3 are two highly reactive reagent systems for the conversion of N-heteroaromatic hydroxy compounds into N-heteroaromatic chlorides or bromides in moderate to excellent yields under mild and acid-free conditions. © 2011 Elsevier Ltd. All rights reserved.

Kaewjuea W.,Prince of Songkla University | Senjuntichai T.,Chulalongkorn University
Computers and Geotechnics | Year: 2014

This paper presents time-dependent response of a cylindrical borehole in a poroelastic medium with an excavation disturbed zone. The general solutions are derived based on Biot's theory of poroelasticity by employing Laplace and Fourier transforms. Both shear modulus and permeability coefficient are assumed to be changed from their original values in the disturbed zone. The general solutions are employed to formulate boundary value problems corresponding to a borehole subjected to axisymmetric loading applied at its surface, and contact problems of a rigid cylindrical plug in a borehole. Selected numerical results are presented to portray the influence of poroelastic effects and the excavation disturbed zone. © 2013.

Pothisiri T.,Chulalongkorn University | Panedpojaman P.,Prince of Songkla University
Engineering Structures | Year: 2013

The mechanical bond-slip relationship for steel-reinforced concrete at elevated temperatures is investigated by using an analytical model based on the smear crack theory and the thick-wall cylinder theory. By considering the concrete cover in its partially cracked elastic stage and the splitting failure as the primary failure mode, a correlation between the slip of the steel rebar and the inner crack radius of the concrete cover can be established. Simplified equations for estimating the bond stress-slip relationship at a designated temperature are derived for practical use. Parametric studies are also conducted to investigate the effect of the variation of compressive strength of concrete, concrete cover and temperature on the prediction of the bond stress-slip relationship obtained by the proposed model. © 2012 Elsevier Ltd.

Anderson G.,CRC Scotland & London | Maes M.,Deakin University | Maes M.,Chulalongkorn University | Maes M.,State University Londrina
Current Psychiatry Reports | Year: 2015

Bipolar disorder (BD) is a complex disorder with a range of presentations. BD is defined by the presentation of symptoms of mania or depression, with classification dependent on patient/family reports and behavioural observations. Recent work has investigated the biological underpinnings of BD, highlighting the role played by increased immune-inflammatory activity, which is readily indicated by changes in pro-inflammatory cytokines or signalling, both centrally and systemically, e.g. increased interleukin-6 trans-signalling. Here, we review the recent data on immune-inflammatory pathways and cytokine changes in BD. Such changes are intimately linked to changes in oxidative and nitrosative stress (O&NS) and neuroregulatory tryptophan catabolites (TRYCATs), both centrally and peripherally. TRYCATs take tryptophan away from serotonin, N-acetylserotonin and melatonin synthesis, driving it down the TRYCAT pathway, predominantly as a result of the pro-inflammatory cytokine induction of indoleamine 2,3-dioxygenase. This has led to an emerging biological perspective on the aetiology, course and treatment of BD. Such data also better integrates the numerous comorbidities associated with BD, including addiction, cardiovascular disorders and increased reporting of pain. Immune-inflammatory, O&NS and TRYCAT pathways are also likely to be relevant biological underpinnings to the significant decrease in life expectancy in BD. © 2015, Springer Science+Business Media New York.

Chusri S.,Prince of Songkla University | Hortiwakul T.,Prince of Songkla University | Silpapojakul K.,Prince of Songkla University | Siriyasatien P.,Chulalongkorn University
American Journal of Tropical Medicine and Hygiene | Year: 2012

Leishmaniasis is an emerging disease in Thailand. Herein, we report on two human immunodeficiency virus (HIV)-infected patients with leishmaniasis who presented with overlapping manifestations between cutaneous and visceral leishmaniasis. Sequencing analysis of the internal transcribed spacer 1 (ITS1) of the ribosomal RNA gene showed that the species was identical to a new species recently described in Thailand. The detection of DNA of this Leishmania species in saliva may have important implications for transmission and epidemiological studies. Copyright © 2012 by The American Society of Tropical Medicine and Hygiene.

Kritsaneepaiboon S.,Prince of Songkla University | Trinavarat P.,Chulalongkorn University | Visrutaratna P.,Chiang Mai University
Acta Radiologica | Year: 2012

Background: Increasing pediatric CT usage worldwide needs the optimization of CT protocol examination. Although there are previous published dose reference level (DRL) values, the local DRLs should be established to guide for clinical practice and monitor the CT radiation. Purpose: To determine the multidetector CT (MDCT) radiation dose in children in three university hospitals in Thailand in four age groups using the CT dose index (CTDI) and dose length product (DLP). Material and Methods: A retrospective review of CT dosimetry in pediatric patients (,15 years of age) who had undergone head, chest, and abdominal MDCT in three major university hospitals in Thailand was performed. Volume CTDI (CTDI vol) and DLP were recorded, categorized into four age groups: ,1 year, 1-,5 years, 5-<10 years, and 10-<15 years in each scanner. Range, mean, and third quartile values were compared with the national reference dose levels for CT in pediatric patients from the UK and Switzerland according to International Commission on Radiological Protection (ICRP) recommendation. Results: Per age group, the third quartile values for brain, chest, and abdominal CTs were, respectively, in terms of CTDI vol: 25, 30, 40, and 45 mGy; 4.5, 5.7, 10, and 15.6 mGy; 8.5, 9, 14, and 17 mGy; and in terms of DLP: 400, 570, 610, and 800 mGy cm; 80, 140, 305, and 470 mGy cm; and 190, 275, 560,765 mGy cm. Conclusion: This preliminary national dose survey for pediatric CT in Thailand found that the majority of CTDIvol and DLP values in brain, chest, and abdominal CTs were still below the diagnostic reference levels (DRLs) from the UK and Switzerland regarding to ICRP recommendation.

Panyakaew P.,Chulalongkorn University | Bhidayasiri R.,Chulalongkorn University | Bhidayasiri R.,University of California at Los Angeles
Journal of Neural Transmission | Year: 2013

Patients with early Parkinson's disease (PD) may not complain of gait difficulties but subtle gait abnormalities may be revealed as part of a "preclinical gait syndrome" when they are challenged by dual tasks. 21 early PD patients (n = 21, mean age 63.5 years, H&Y 1.62, disease duration <5 years, mean UPDRS-III 7.7) who did not have gait complaints were as compared to age- and gender-matched healthy controls (n = 21). Memory function was not different between the two groups. Under normal walking conditions, there were no significant differences in gait parameters between the patients and the control group. In both groups, normalized gait velocity decreased in response to dual tasking in a parallel fashion (p < 0.001). Similarly, gait variability increased in both groups with dual tasking although not statistically significant. In PD patients, the performance of an additional task resulted in an increased number of cadences (p = 0.04), a reduction in swing time (p = 0.02) and cycle time (p = 0.04) compared with the control group but there was no significant reduction in normalized velocity. Stride width also increased in the PD patients. The addition of a cognitive task may affect certain aspects of gait and is able to elicit subclinical deficits in early PD patients. In an attempt to maintain velocity, early PD patients develop compensatory mechanisms by increasing cadence and decreasing swing time and cycle time. Increased step width helps support balance, and prevents going beyond the base-of-support which may predispose to unsteadiness and falls. We propose that these findings occur as part of a spectrum of a "preclinical gait syndrome" and longitudinal studies are needed to assess the predictive values of these early markers of gait deficits. © 2013 Springer-Verlag Wien.

Dulnee S.,Chulalongkorn University | Luengnaruemitchai A.,Chulalongkorn University | Wanchanthuek R.,Mahasarakham University
International Journal of Hydrogen Energy | Year: 2014

In this work, Au supported over ZnO prepared by photodeposition was applied to prepare nano-size Au catalysts by utilizing UV light for the preferential oxidation (PROX) of CO. The results demonstrated that Au can be dispersed homogeneously over ZnO in the size range of 1-2 nm with a narrow size distribution. It was clearly seen that the preparation parameters (i.e. irradiation time, precipitant concentration, calcination, and storage condition) had a significant effect on the catalytic activity. Among the variables studied, low concentrations of precipitant and long irradiation time were by far the most influential on the catalytic activity. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Futrakul N.,Chulalongkorn University | Futrakul P.,Academy of science
Renal Failure | Year: 2012

Renal microvascular disease reflected directly by peritubular capillary flow reduction and indirectly by renal function impairment has been documented in early diabetic nephropathy (DN) associated with normoalbuminuria and normal serum creatinine concentration. The renal microvascular disease observed in early DN [chronic kidney disease (CKD) stages 12] could progress under current practice to late DN (CKD stages 35) with a further reduction in peritubular capillary flow. This advanced renal microvascular disease in late DN is characterized by therapeutic resistance to vasodilators and altered vascular homeostasis associated with impaired nitric oxide production. The renal microvascular disease is progressive as the disease severity progresses and eventually induces chronic renal ischemia and a progressive tubulointerstitial fibrosis. Further study has revealed that early DN is associated with an adequately functional vascular homeostasis. Therefore, recognition and treatment of early renal microvascular disease at early DN (stages 12) could enhance renal perfusion and restore renal function.

Bhidayasiri R.,Chulalongkorn University | Bhidayasiri R.,University of California at Los Angeles | Fahn S.,Columbia University | Weiner W.J.,University of Maryland, Baltimore | And 3 more authors.
Neurology | Year: 2013

Objective: To make evidence-based recommendations regarding management of tardive syndromes (TDS), including tardive dyskinesias (TDD), by addressing 5 questions: 1) Is withdrawal of dopamine receptor blocking agents (DRBAs) an effective TDS treatment? 2) Does switching from typical to atypical DRBAs reduce TDS symptoms? 3) What is the efficacy of pharmacologic agents in treating TDS? 4) Do patients with TDS benefit from chemodenervation with botulinum toxin? 5) Do patients with TDS benefit from surgical therapy? Methods: PsycINFO, Ovid MEDLINE, EMBASE, Web of Science, and Cochrane were searched (1966-2011). Articles were classified according to a 4-tiered evidence-rating scheme; recommendations were tied to the evidence. Results and recommendations: Clonazepam probably improves TDD and ginkgo biloba probably improves TDS (both Level B); both should be considered as treatment. Risperidone may improve TDS but cannot be recommended as treatment because neuroleptics may cause TDS despite masking symptoms. Amantadine and tetrabenazine might be considered as TDS treatment (Level C). Diltiazem should not be considered as TDD treatment (Level B); galantamine and eicosapentaenoic acid may not be considered as treatment (Level C). Data are insufficient to support or refute use of acetazolamide, bromocriptine, thiamine, baclofen, vitamin E, vitamin B6, selegiline, clozapine, olanzapine, melatonin, nifedipine, fluperlapine, sulpiride, flupenthixol, thiopropazate, haloperidol, levetiracetam, quetiapine, ziprasidone, sertindole, aripiprazole, buspirone, yi-gan san, biperiden discontinuation, botulinum toxin type A, electroconvulsive therapy, a-methyldopa, reserpine, and pallidal deep brain stimulation as TDS treatments (Level U). Data are insufficient to support or refute TDS treatment by withdrawing causative agents or switching from typical to atypical DRBA (Level U).© 2013 American Academy of Neurology.

Pothisiri T.,Chulalongkorn University | Panedpojaman P.,Prince of Songkla University
Construction and Building Materials | Year: 2012

A mechanical model of bonding between steel rebar and concrete at elevated temperatures is proposed based on the smear crack theory and the thick-wall cylinder in its partially cracked elastic stage. The relationship between the splitting bond strength and the inner crack radius of the concrete is established by taking into account the variation of the material properties with temperature and the differential thermal expansion of the rebar and the concrete. The model is validated by using previous experimental results on the bond strength. Parametric studies are conducted to investigate the effect of the variation of compressive strength of concrete, concrete cover and temperature on the bond strength degradation. It has been found that the estimate of bond strength based on the previous studies may be unconservative if the concrete cover is relatively small compared with the rebar diameter in which case the concrete cover is more susceptible to splitting failure. © 2011 Elsevier Ltd. All rights reserved.

Panedpojaman P.,Prince of Songkla University | Thepchatri T.,Chulalongkorn University | Limkatanyu S.,Prince of Songkla University
Thin-Walled Structures | Year: 2014

To complement available design methods, this study develops a practical and economical approach to estimate shear strength of non-composite symmetric and asymmetric cellular beams, based on failure by local web-post buckling. Influence of geometric web-post parameters on the buckling strength and mechanism, such as section size, opening depth ratio, spacing ratio and tee depth, are investigated with a validated finite element (FE) web-post model. The validation is against 13 cases reported in the literature, and 390 parametric web-post models are analyzed. Tee depth is found to be the key parameter distinguishing failure modes between buckling and Vierendeel bending. The buckling design equation is adopted based on a simple strut model. The observed stress distributions from simulations suggest half the web-post width for the effective strut width and half the length of a line segment tangent to neighboring openings as the strut length. Based on the simulation study, an effective length is proposed to incorporate the effects of restraint due to the tee section and the stress variation around the opening. The strut models of the upper and lower parts of the web-post are separately computed for their buckling shear strength according to BS EN 1993-1-1 and ANSI/AISC 360-10. The shear strength of each part is related to the web-post shear strength through the vertical shear area of the tee section. Accuracy of the proposed model is validated against existing experiments or their FE models. The new design equations facilitate safe and cost-effective design of cellular beams. © 2013 Elsevier Ltd.

Choedkiatsakul I.,Chulalongkorn University | Ngaosuwan K.,Rajamangala University of Technology at Krungthep | Cravotto G.,University of Turin | Assabumrungrat S.,Chulalongkorn University
Ultrasonics Sonochemistry | Year: 2014

This paper investigates the production of biodiesel from palm oil using a combined mechanical stirred and ultrasonic reactor (MS-US). The incorporation of mechanical stirring into the ultrasonic reactor explored the further improvement the transesterification of palm oil. Initial reaction rate values were 54.1, 142.9 and 164.2 mmol/L min for the mechanical-stirred (MS), ultrasonic (US) and MS-US reactors, respectively. Suitable methanol to oil molar ratio and the catalyst loading values were found to be 6 and 1 of oil, respectively. The effect of ultrasonic operating parameters; i.e. frequency, location, and number of transducer, has been investigated. Based on the conversion yield at the reactor outlet after 1 h, the number of transducers showed a relevant role in the reaction rate. Frequency and transducer location would appear to have no significant effect. The properties of the obtained biodiesel (density, viscosity, pour point, and flash point) satisfy the ASTM standard. The combined MS-US reactors improved the reaction rate affording the methyl esters in higher yield. © 2013 Elsevier B.V. All rights reserved.

Han X.X.,Kwansei Gakuin University | Pienpinijtham P.,Chulalongkorn University | Zhao B.,Jilin University | Ozaki Y.,Kwansei Gakuin University
Analytical Chemistry | Year: 2011

Studies have shown that many adverse health effects are associated with human exposure to dietary or environmental estrogens. Therefore, the development of rapid and highly sensitive detection methods for estrogens is very important and necessary to maintain hormonal concentration below the safety limit. Herein, we demonstrate a simple and rapid approach to detect trace amounts of phenolic estrogen based on surface-enhanced resonance Raman scattering (SERRS). Because of a coupling reaction between diazonium ions and the phenolic estrogens, azo compounds are formed with strong SERRS activity, which allows phenolic estrogen recognition at subnanomolar levels in solution. The proposed protocol has multiplexing capability, because each SERRS fingerprint of the azo dyes specifically corresponds to the related estrogen. Moreover, it is universal and highly selective, not only for phenolic estrogens but also for other phenolic molecules, even in complex systems. © 2011 American Chemical Society.

Ngorsuraches S.,Prince of Songkla University | Meng W.,China Health Insurance Research Association | Kim B.-Y.,Health Insurance Review and Assessment Services | Kulsomboon V.,Chulalongkorn University
Value in Health | Year: 2012

Objective: To provide a comparison of national drug reimbursement decision-making, including an update of economic evaluation roles and barriers, in Thailand, China, and South Korea. Methods: Documentary reviews supplemented by experiences of policymakers. Results: National health insurance policy in all the three countries has been developed toward coverage for all. It leads to higher health-care expenditures and requires a good reimbursement system for health-care services, including drugs. Drug reimbursement decision-making in these countries is to develop a reimbursement list with the help of various committees having different roles. Primarily, they assess the clinical and safety evidence. Economic evidence, including budget impact and pharmacoeconomic evaluation, has also been very important for their reimbursement decision-making. This evidence is sometimes used in negotiation mechanism, which allows pharmaceutical companies to lower their drug prices and leads to lower overall drug expenditures. Several common barriers, for example, human capacity and data availability, for obtaining economic evidence in all the three countries, however, still exist. Conclusions: Drug reimbursement decision-making in Thailand, China, and South Korea is in its transition period. It seems to run in the same direction, for example, guideline development and pharmacoeconomic evaluation agency establishment. Pharmacoeconomic evaluation plays important roles in the efficiency of drug reimbursement decision-making, even though there are several barriers to be overcome. © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR).

Manomaivibool P.,Lund University | Manomaivibool P.,Mae Fah Luang University | Vassanadumrongdee S.,Chulalongkorn University
Resources, Conservation and Recycling | Year: 2012

This article assesses the potential and the limitations of Thailand's proposed policy which would have local governments buy back targeted waste electronic and electrical equipment (WEEE) from households at designated locations. The proposal relies on the premise that a monetary incentive at the time of disposal is needed to gain participation from households which would otherwise sell to private waste dealers who purchase and then introduce WEEE into the pollution-causing informal recycling sector. To see whether the premise and the proposed policy were valid, a large-scale survey of 1529 households was conducted. This article reports these households' past behavior in, and future preferences for the disposal of 10 particular WEEE items: televisions, digital cameras, portable media players, desktop printers, mobile phones, personal computers, refrigerators, air conditioners, fluorescent lamps, and dry-cell batteries, which were prioritized under the Thai WEEE Strategy. We also tested the effects of population density, distance to the hypothetical drop-off location, car ownership, product weight and the financial incentive offered on the respondents' past decisions and future choices. The survey results show that creating a standardized program to buy back WEEE at designated drop-off locations has a potential of getting household WEEE introduced into the formal recycling sector. It could also help eliminate the psychological hurdle of parting with obsolete products and encourage their disposal. However, the program may not be enough to convince people to stop selling WEEE to waste dealers, especially if they had done so in the past. Based on the results, recommendations to improve the viability of the proposed policy and to direct and enhance future research are outlined. © 2012 Elsevier B.V. All rights reserved.

Bhidayasiri R.,Chulalongkorn University | Bhidayasiri R.,University of California at Los Angeles | Truong D.D.,Fountain
Parkinsonism and Related Disorders | Year: 2012

It is now recognized that the neuropathology of early Parkinson's disease (PD) is not limited to the nigrostriatal dopaminergic system, but also involves various brainstem nuclei, the hypothalamus, the olfactory system, and the peripheral autonomic nervous system. Given the disseminated neuropathology of early PD, the earliest clinical signs include a myriad of non-motor manifestations including sleep-wake cycle regulation, cognition, mood and motivation, olfactory and gustatory functions, autonomic functions, and sensory and pain processing. Despite this realization, there is clearly a paucity of trials that have systematically evaluated the treatment of non-motor symptoms of PD in the early stages. For example, only one large-scale, placebo-controlled randomized trial has been conducted on the treatment of depression in PD patients. There are no reports of randomized controlled trials of therapeutic agents looking at the frequently reported anxiety and fatigue in early PD patients. Based on this lack of evidence, therapy for early non-motor manifestations is often ignored and the focus remains on dopamine replacement strategies with main outcomes being restricted to motor measurements, such as the Unified Parkinson's Disease Rating Scale. This article presents the case for prioritizing welldesigned, controlled clinical trials of therapeutic interventions focusing on non-motor symptoms in early PD patients. © 2011 Elsevier Ltd.

Aramwit P.,Chulalongkorn University | Siritientong T.,Chulalongkorn University | Srichana T.,Prince of Songkla University
Waste Management and Research | Year: 2012

Silk is composed of two major proteins, fibroin (fibrous protein) and sericin (globular, gumming protein). Fibroin has been used in textile manufacturing and for several biomaterial applications, whereas sericin is considered a waste material in the textile industry. Sericin has recently been found to activate the proliferation of several cell-lines and has also shown various biological activities. Sericin can form a gel by itself; however, after mixing with other polymers and cross-linking it can form a film or a scaffold with good characteristics that can be used in the cosmetic and pharmaceutical industries. Sericin is proven to cause no immunological responses, which has resulted in a more acceptable material for biological applications. © The Author(s) 2012.

Thirabanjasak D.,Chulalongkorn University | Tantiwongse K.,Chulalongkorn University | Thorner P.S.,Chulalongkorn University | Thorner P.S.,Hospital for Sick Children | Thorner P.S.,University of Toronto
Journal of the American Society of Nephrology | Year: 2010

Some reports suggest that autologous hematopoietic stem cell transplantation holds potential for treatment of renal diseases such as lupus nephritis, but the safety of delivering various stem cell types (hematopoietic, mesenchymal, and endothelial precursors) is not well established. Here, we report a case of lupus nephritis treated by direct renal injection of autologous stem cells recovered from peripheral blood. The patient developed masses at the sites of injection and hematuria. We suspected transitional cell carcinoma but nephrectomy revealed that the masses were angiomyeloproliferative lesions. We believe that this previously undescribed pathologic entity is stem cell-derived or -induced. The biologic potential, including the neoplastic potential, of this lesion is unknown. This case illustrates that the development of angiomyeloproliferative lesions is a possible complication of stem cell therapy. Copyright © 2010 by the American Society of Nephrology.

Bhidayasiri R.,Chulalongkorn University | Bhidayasiri R.,University of California at Los Angeles | Reichmann H.,Universitatsklinikum Carl Gustav Carus
Journal of Neural Transmission | Year: 2013

As there are no definite diagnostic tests or reliable biomarkers for Parkinson disease (PD), its diagnosis still relies on the presence of a combination of cardinal motor features, along with the exclusion of other causes of Parkinsonism and the presence of some of supportive features. To date, several diagnostic criteria have been developed for different purposes through expert opinions or comprehensive review of the literature. However, none of them are without limitations. In this article, we review different diagnostic criteria for PD which have been published in the English medical literature, highlighting specific limitations and pitfalls. With considerable progress in the understanding of PD, particularly in a view of diverse clinical symptomatology and its evolution, it will be difficult to establish a single criterion that is capable of capturing all cases at different disease stages. Rather, we should aim to develop a set of criteria which include a consensus on clinical gold standard or reliable biomarkers at different levels of diagnostic certainty for different purposes. Despite a more refined set of criteria that may aid in the recognition of PD, the accuracy of its diagnosis still largely depends on the observational skills and clinical sensitivity of the treating physician. © 2013 Springer-Verlag Wien.

Rianthavorn P.,Chulalongkorn University | Limwattana S.,Prince of Songkla University
World Journal of Urology | Year: 2015

Purpose: To determine the diagnostic accuracy of anteroposterior renal pelvic diameter (APD) measurement and the society for fetal urology (SFU) grading in neonatal ultrasonography (USG) for detecting uropathy in newborns having antenatal isolated hydronephrosis (IH), characterized by hydronephrosis without ureter and bladder abnormalities, and to study time to resolution and factors predicting resolution of insignificant hydronephrosis. Methods: Ninety-six healthy newborns (129 kidneys) with IH, who underwent USG at age 7–30 days and voiding cystourethrography (VCUG) in conjunction with diuretic renography (DR) if APD > 10 mm or SFU grade 3–4 in neonatal USG, and at least a 12-month follow-up were divided into significant and insignificant hydronephrosis using the combined data of sequential USG, VCUG, and DR as the reference standard. Results: Areas under the receiver operating characteristic plots (95 % CI) were 0.86 (0.79–0.94) versus 0.81 (0.73–0.89); p = 0.08, and 87.6 versus 79.8 % of cases were correctly classified, for APD ≥ 16 mm versus SFU grade 4, respectively. Ureteropelvic junction obstruction (UPJO) was the most common uropathy diagnosed. Of 85 kidneys with insignificant hydronephrosis, 57 underwent spontaneous resolution. The resolution rates were 24, 40, and 68 % at age 6, 12, and 24 months, respectively. APD was the only independent factor predicting resolution with the hazard ratio of 0.83 (95 % CI 0.74–0.92; p = 0.001). Conclusions: In IH, neonatal USG was a useful diagnostic tool to detect uropathy, mainly UPJO. Further investigation should be recommended when APD ≥ 16 mm or SFU grade 4. © 2015, Springer-Verlag Berlin Heidelberg.

Jainkittivong A.,Chulalongkorn University | Aneksuk V.,Chulalongkorn University | Langlais R.P.,University of Texas Health Science Center at San Antonio
Gerodontology | Year: 2010

Objective: To determine the prevalence of oral mucosal lesions (OMLs) and denture-related mucosal lesions (DMLs) in denture wearers and to co-relate the prevalence with age, gender, type of denture and any systemic conditions. Materials and methods: Dental records of 380 denture wearers were retrospectively reviewed for OMLs and DMLs. Results: We found 45% of the denture wearers had DMLs and 60.8% had OMLs not related to denture wearing. Although the prevalence of DMLs was higher in complete denture wearers than in partial denture wearers (49% vs. 42.2%), this difference was not significant. The most common DMLs were traumatic ulcer (19.5%) and denture-induced stomatitis (18.1%). When analysed by type, traumatic ulcer, denture hyperplasia, frictional keratosis and candidiasis were more common in complete denture wearers, whereas denture-induced stomatitis was more common in partial denture wearers. Frictional keratosis was more common in men than in women. The prevalence of OMLs not related to denture wearing was higher in complete denture wearers than in partial denture wearers, and the most common OML was fissured tongue (27.6%). No association between DMLs and systemic conditions or xerostomic drugs was noted. Conclusion: No differences in the prevalence of DMLs in association with denture type were found. The prevalence of OMLs not related to denture wearing was higher in complete denture wearers than in partial denture wearers. This difference was affected by age, and the data were similar to the findings observed in the elderly. © 2009 The Gerodontology Society and John Wiley & Sons A/S.

Koedsin W.,Chulalongkorn University | Koedsin W.,Prince of Songkla University | Vaiphasa C.,Chulalongkorn University
Remote Sensing | Year: 2013

Understanding the dynamics of mangroves at the species level is the key for securing sustainable conservation of mangrove forests around the globe. This study demonstrates the capability of the hyper-dimensional remote sensing data for discriminating diversely-populated tropical mangrove species. It was found that five different tropical mangrove species of Southern Thailand, including Avicennia alba, Avicennia marina, Bruguiera parviflora, Rhizophora apiculata, and Rhizophora mucronata, were correctly classified. The selected data treatment (a well-established spectral band selector) helped improve the overall accuracy from 86% to 92%, despite the remaining confusion between the two members of the Rhizophoraceae family and the pioneer species. It is therefore anticipated that the methodology presented in this study can be used as a practical guideline for detailed mangrove species mapping in other study areas. The next stage of this work will be to exploit the differences between the leaf textures of the two Rhizophoraceae mangroves in order to refine the classification outcome. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Bhidayasiri R.,Chulalongkorn University | Bhidayasiri R.,University of California at Los Angeles
Parkinsonism and Related Disorders | Year: 2011

Complex cervical dystonia is a subgroup of cervical dystonia (CD) characterised by a combination of head deviations in more than one plane. In addition to superficial neck muscles, deep-cervical muscles contribute to a broad range of neck movements. These deep muscles include prevertebral muscles for primary neck flexion, lateral vertebral muscles for shoulder elevation and head tilt and a posterior group of muscles for neck extension. The authors describe three cases of complex deviations of the neck including anterocollis, retrocollis and lateral or sagittal shifts with involvement of deep-cervical muscles, which are not easily accessible by routine botulinum toxin (BoNT) therapy. Incomplete muscle selection may be one of the causes of treatment failures with BoNT in patients with complex CD, and targeting of deep-cervical muscles should be considered when patients exhibit complex deviations involving anterocollis, retrocollis, lateral or sagittal shifts. © 2011 Elsevier Ltd.

Nunthaboot N.,Mahasarakham University | Pianwanit S.,Chulalongkorn University | Kokpol S.,Chulalongkorn University | Tanaka F.,Mahidol University
Physical Chemistry Chemical Physics | Year: 2011

The mechanism of photoinduced electron transfer (PET) from the aromatic amino acids (Trp32, Tyr35 and Trp106) to the excited flavin mononucleotide (FMN) in the wild type (WT) and four single amino acid substitution isomers (E13T, E13Q, W32A and W32Y) of FMN binding protein (FBP) from the Desulfovibrio vulgaris (Miyazaki F) were simultaneously analyzed (Method A) with the Marcus-Hush (MH) theory and Kakitani-Mataga (KM) theory using ultrafast fluorescence dynamics of these proteins. In addition, the PET mechanism of the WT, E13T and E13Q FBP systems (Method B) were also analyzed with both MH and KM theories. The KM theory could describe all of the experimental fluorescence decays better than the MH theory by both Methods A and B. The PET rates were found to largely depend on the electrostatic energies between photo-products, isoalloxazine (Iso) anion and the PET donor cations, and the other ionic groups, and hence on static dielectric constants. The dielectric constant (εDA0) around the PET donors and acceptor was separately determined from those (εj0, j = WT, E13T, E13Q, W32Y and W32A) in the domain between the Iso anion or the donor cations and the other ionic groups in the proteins. The values of εDA0 were always lower than those of εj0, which is reasonable because no amino acid exists between the PET donors and acceptor in all systems. The values of the dielectric constants εj0 (j = WT, E13T and E13Q) were similar to those obtained previously from the analysis of the crystal structures and the average lifetimes of these FBP proteins. Energy gap law in the FBP systems was examined. An excellent parabolic function of the logarithms of the PET rates was obtained against the total free energy gap. The PET in these FBP isomers mostly took place in the so-called normal region, and partly in the inverted region. © the Owner Societies. 2011.

Techaumnat B.,Chulalongkorn University | Kadonaga M.,Ricoh Company
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2011

This paper presents the analysis of the electrostatic force on a nonuniformly charged dielectric particle resting on a dielectric solid. The purpose of the analysis is to clarify the force enhancement caused by the nonuniform charging when the particle is on the dielectric solid, and to examine the role of the dielectric solid on the force behavior in the presence of an external electric field. The method of images using multipoles is applied to electric field calculation, and the electrostatic force is determined from the Maxwell stress. The analytical results show significant force enhancement due to nonuniform charging even in the case where the particle and the dielectric solid have the same dielectric-constant value. However, with an externally applied electric field, the nonuniform charging also results in higher force magnitude for detachment of the particle from the plane in comparison with the case of uniform charging. The roles of the dielectric constants of the media involved on the electrostatic force behavior are investigated. Critical difficulty for the detachment is not found for a particle with dielectric constant equal to 4, which is remarkably different from the corresponding case of a particle lying on a conducting plane. © 2006 IEEE.

Aramwit P.,Chulalongkorn University | Bang N.,Chulalongkorn University | Srichana T.,Prince of Songkla University
Food Research International | Year: 2010

Mulberry fruit is well known as a good source of anthocyanins with many biological activities. However, there are several colors of mulberry fruits, even from the same species, which may generate different amounts of anthocyanins. This study investigates anthocyanin content and antioxidant levels as well as tyrosinase inhibition activity in the extract from various colors of mulberry fruit, Morus alba. The effects of heat and light, which the extract may be exposed to during food processing, on anthocyanin and antioxidant activities are also evaluated. Our results show that purple-colored mulberry fruit extract contains the highest levels of anthocyanin and strongest antioxidant as well as anti-tyrosinase properties compared with other colors mulberry fruit extracts. Light or heat exposure by incubation of the mulberry fruit extract at 70 °C for 10 h significantly deteriorated total anthocyanin and ascorbic acid content and led to a corresponding increase of the IC50 values. © 2010 Elsevier Ltd. All rights reserved.

Seentrakoon B.,Chulalongkorn University | Junhasavasdikul B.,Chemical Innovation Co. | Chavasiri W.,Chulalongkorn University
Polymer Degradation and Stability | Year: 2013

Natural rubber/rutile-TiO2 nanocomposites (NR/n-TiO 2(R) composites) with different n-TiO2(R) contents were prepared. The n-TiO2(R) with median particle size (d50) of 73 nm was successfully prepared from commercial micron-TiO2(R) by ultrasonication. NR incorporated with n-TiO2(R) shows the good performance in mechanical properties as well as UV-protection and antibacterial properties. The mechanical performance of NR/n-TiO2(R) composites was enhanced with an increase of n-TiO2(R) content up to the optimum content at 5 phr (parts per hundred parts of rubber) and then declined. In addition, the prepared NR/n-TiO2(R) composites possess the UV-protection material. The UV-protection property of NR nanocomposites was evaluated by measuring the evolution of carbonyl absorption band from ATR-FTIR spectra, surface cracking, and mechanical properties after UV irradiation. The presence of n-TiO2(R) exhibits significant improvement in photo-degradation by UV irradiation compared to the unfilled NR. More importantly, the obtained NR/n-TiO2(R) composites demonstrate effective antibacterial property against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the strong antibacterial property of the prepared NR nanocomposites was obtained at the only loading level of 1 phr of n-TiO2(R). The prepared NR/n-TiO2(R) composites could be used as a novel antibacterial material. © 2012 Elsevier Ltd. All rights reserved.

Dangtungee R.,King Mongkut's University of Technology Bangkok | Supaphol P.,Chulalongkorn University
Polymer Testing | Year: 2010

The rheological properties in terms of melt rheology and extrudate swell of low-density polyethylene (LDPE) filled with sodium chloride (NaCl) of varying particle size (i.e., 45, 75, and 125 μm) in the range of 5-25 wt.% were investigated by capillary rheometry. The real shear stress increased monotonously with increasing apparent shear rate, with the rate of change decreasing with increasing apparent shear rate. At an apparent shear rate greater than about 400 s-1, the real shear stress increased with increasing salt content and, at a given apparent shear rate, the real shear stress increased slightly with increasing salt particle size. The shear viscosity decreased monotonously with increasing real shear rate. Regardless of the salt content, the extrudate swell increased with the initial increase in the apparent shear rate to reach a plateau value. After a critical apparent shear rate in the range of 500-1200 s-1, and regardless of the salt particle size, the extrudate swell decreased with increasing salt content. Lastly, the extrudate swell tended to be suppressed when a capillary die with a high L/D ratio was used.

Ananworanich J.,U.S. Army | Ananworanich J.,Foundation Medicine | Avihingsanon A.,Red Cross | Avihingsanon A.,Chulalongkorn University
Journal of Acquired Immune Deficiency Syndromes | Year: 2014

Asia is seeing a rise in noncommunicable diseases in their general population and among people living with HIV. Many Asians have low body weight, which can lead to higher plasma concentrations of antiretrovirals and, as a result, their toxicities. Examples are metabolic complications from protease inhibitors, chronic kidney disease from tenofovir, and hepatotoxicity from nevirapine. Asia has not only the highest burden of hepatitis B viral infection than any other continent but also a predominance of genotypes B and C, the latter associated with higher risk for hepatocellular carcinoma. HIV-associated neurocognitive disorders are equally common among Asians as other populations. Diastolic dysfunction and asymptomatic myocardial ischemia are not infrequent. Non-Hodgkin lymphoma is the most common AIDS-related cancer, whereas Kaposi sarcoma is relatively infrequent. Emerging data show high prevalence of human papillomavirus-associated anal dysplasia in men who have sex with men. Resource-limited countries in Asia suffer from lack of resources for national screening programs of noncommunicable diseases, which, in turn, limits the epidemiologic data that exist to guide the use of national health resources. © 2014 by Lippincott Williams & Wilkins.

Matthews A.J.,University of East Anglia | Singhruck P.,University of East Anglia | Singhruck P.,Chulalongkorn University | Heywood K.J.,University of East Anglia
Climate Dynamics | Year: 2010

New diagnostics of the Madden-Julian oscillation (MJO) cycle in ocean temperature and, for the first time, salinity are presented. The MJO composites are based on 4 years of gridded Argo float data from 2003 to 2006, and extend from the surface to 1,400 m depth in the tropical Indian and Pacific Oceans. The MJO surface salinity anomalies are consistent with precipitation minus evaporation fluxes in the Indian Ocean, and with anomalous zonal advection in the Pacific. The Argo sea surface temperature and thermocline depth anomalies are consistent with previous studies using other data sets. The near-surface density changes due to salinity are comparable to, and partially offset, those due to temperature, emphasising the importance of including salinity as well as temperature changes in mixed-layer modelling of tropical intraseasonal processes. The MJO-forced equatorial Kelvin wave that propagates along the thermocline in the Pacific extends down into the deep ocean, to at least 1,400 m. Coherent, statistically significant, MJO temperature and salinity anomalies are also present in the deep Indian Ocean. © 2009 Springer-Verlag.

Wannajuk K.,Chulalongkorn University | Jamkatoke M.,Burapha University | Tuntulani T.,Chulalongkorn University | Tomapatanaget B.,Chulalongkorn University
Tetrahedron | Year: 2012

The boronic acid anthraquinones, oHAQB and pHAQB, have been designed, and demonstrated to serve as fluorogenic biosensors for glucose. The sensory molecule, oHAQB, has exhibited the specific-glucose sensing via the GOx enzymatic reaction. In this contribution, the fluorescence changes of oHAQB reasonably correspond to the concentration of glucose upon the conversion of boronic acid to hydroxy based sensor by H 2O 2 generated from glucose along with GOx enzymatic reaction. Our sensing ensemble was then successfully applied to determine the glucose concentration in the range of 0.08-0.42 mM. The limit of detection (LOD) of oHAQB for glucose detection using the GOx enzymatic probe is approximately 0.011 mM. © 2012 Elsevier B.V. All rights reserved.

Limjirakan S.,Chulalongkorn University | Limsakul A.,Environmental Research and Training Center
Journal of the Meteorological Society of Japan | Year: 2012

Based on updated quality controlled daily records, extreme events were defined using temperature indices proposed by the Commission for Climatology/Climate Variability and Predictability project's Expert Team on Climate Change Detection, Monitoring and Indices, and temporal trends during the 1970-2009 period were examined in Thailand. Results revealed that Thailand has indeed experienced significant country-wide warming over the last four decades, and extreme events associated with both the cold and warm extremes of daily minimum and maximum temperature distributions have changed accordingly. Trends in temperature indices showed much spatial trend coherence and widespread significant warming, generally consistent with the regional evidence recently documented in other Asia-Pacific Network countries. Significant upward trends in temperature extreme indices were found in the annual number of warm nights and days, the annual occurrence of warm spells, tropical nights, summer days, and the highest and lowest values of daily minimum temperatures. In contrast, significant downward trends were observed in the annual number of cold nights and days, the annual occurrence of cold spells, diurnal temperature range and annual extreme temperature range. Changes in these temperature extreme indices were consistent with a significant shift in the temperature distribution toward warmer conditions over the recent decades. To address changes in Thailand's temperature more clearly, however, the plausible underlying mechanisms, including urbanization effects, need to be further studied. © 2012, Meteorological Society of Japan.

Hemachudha T.,Chulalongkorn University | Ugolini G.,French National Center for Scientific Research | Wacharapluesadee S.,Chulalongkorn University | Sungkarat W.,Mahidol University | And 2 more authors.
The Lancet Neurology | Year: 2013

Rabies is an almost invariably fatal disease that can present as classic furious rabies or paralytic rabies. Recovery has been reported in only a few patients, most of whom were infected with bat rabies virus variants, and has been associated with promptness of host immune response and spontaneous (immune) virus clearance. Viral mechanisms that have evolved to minimise damage to the CNS but enable the virus to spread might explain why survivors have overall good functional recovery. The shorter survival of patients with furious rabies compared with those with paralytic rabies closely corresponds to the greater amount of virus and lower immune response in the CNS of patients with the furious form. Rabies virus is present in the CNS long before symptom onset: subclinical anterior horn cell dysfunction and abnormal brain MRI in patients with furious rabies are evident days before brain symptoms develop. How the virus produces its devastating effects and how it selectively impairs behaviour in patients with furious rabies and the peripheral nerves of patients with paralytic rabies is beginning to be understood. However, to develop a pragmatic treatment strategy, a thorough understanding of the neuropathogenetic mechanisms is needed. © 2013 Elsevier Ltd.

Chaisuparat R.,Chulalongkorn University | Sawangarun W.,Naresuan University | Scheper M.A.,University of Maryland, Baltimore
Histopathology | Year: 2012

Aims: Malignant odontogenic tumours (MOTs) are rare neoplasms occurring primarily within the jaw. The objective of this study was to determine the incidence, demographics and clinicopathological features of the MOTs from two institutions. Methods and results: The records of the Department of Oral Pathology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand and the Department of Oncology and Diagnostic Sciences, Dental School, University of Maryland, Baltimore, USA were searched from 1991 to 2010; we identified 17 cases of previously diagnosed MOTs. All cases were reviewed independently of the previous diagnosis by two blinded oral pathologists and reclassified based on the 2005 World Health Organization classification of head and neck tumours. In this study we describe in detail these 17 cases which presented with an average age of 50.29years and a male to female ratio of 2.4:1. These cases included five ameloblastic carcinomas, four atypical ameloblastomas, three primary intraosseous squamous cell carcinomas, three intraosseous mucoepidermoid carcinomas and two clear cell odontogenic carcinomas. All cases were treated by surgical resection and one patient with ameloblastic carcinoma received postoperative radiotherapy. Conclusions: Malignant odontogenic tumours are considered rare central odontogenic lesions. Awareness of their existence, rapid diagnosis and successful treatment using surgery, radiation and/or chemotherapy is critical to patient survival. © 2012 Blackwell Publishing Ltd.

Piya-Areetham P.,Chulalongkorn University | Prasassarakich P.,Chulalongkorn University | Rempel G.L.,University of Waterloo
Journal of Molecular Catalysis A: Chemical | Year: 2013

A water-soluble rhodium catalyst has been found to be an efficient catalyst for hydrogenation of unsaturated polymers in the absence of any organic solvent. Natural rubber (NR) latex and synthetic polyisoprene (PIP) emulsion were hydrogenated using rhodium trichloride (RhCl3·3H 2O) and different ligand types, triphenylphosphine (PPh3), trisulfonated triphenylphosphine (TPPTS) and monosulfonated triphenylphosphine (TPPMS) as a catalyst precursor. The hydrogenated NR and PIP were characterized by proton nuclear magnetic resonance (1H NMR). A low degree of hydrogenation (HD) was observed when using RhCl3/PPh3 or RhCl3/TPPTS. In contrast, a high HD of 85.8% was achieved by using RhCl3/TPPMS. The catalytic behavior could be well explained by the Hartley ionic spherical micelle model. The HD increased with increasing catalyst amount, reaction temperature and H2 pressure. The catalyst activity of RhCl3/TPPMS for NR hydrogenation was found to be lower than that for PIP hydrogenation for all conditions due to impurities in the latex, including protein. The hydrogenated NR (86%HD) has high thermal stability with a maximum decomposition temperature of 466 °C and a glass transition temperature of -60 °C. From dynamic mechanical analysis, hydrogenated NR had a maximum storage modulus due to the saturated carbon domains of the ethylene-propylene segments in the polymer chains.

Tangdhanakanond K.,Chulalongkorn University | Lee D.H.,Sungkyunkwan University
School Psychology International | Year: 2014

The purpose of the present study was to compare Thai and Korean college students on their perceptions of the roles and functions of school psychologists. One hundred and ninety-three Thai college students and 238 Korean counterparts participated in this study. Students rated the importance of various roles/functions of a school psychologist and specified who should assume those roles/functions in the absence of a school psychologist. Results indicated that Thai education students rated the roles/functions of counselling students, intervention, consultation with teachers, and consultation with parents, significantly higher (p < 0.01) than their Korean counterparts. However, there was no significant difference between the two groups on the assessment role (p > 0.05). Thai students expected their relatives and school personnel and other related people outside of the schools to fill in the vacuum of a school psychologist significantly (p < 0.01) more than their Korean counterparts did in all roles and functions. © The Author(s) 2013 Reprints and permissions:

Lopresti A.L.,Murdoch University | Maes M.,Deakin University | Maes M.,Chulalongkorn University | Maker G.L.,Murdoch University | And 2 more authors.
Journal of Affective Disorders | Year: 2014

Background Curcumin, the principal curcuminoid derived from the spice turmeric, influences several biological mechanisms associated with major depression, namely those associated with monoaminergic activity, immune-inflammatory and oxidative and nitrosative stress pathways, hypothalamus-pituitary-adrenal (HPA) axis activity and neuroprogression. We hypothesised that curcumin would be effective for the treatment of depressive symptoms in individuals with major depressive disorder. Methods In a randomised, double-blind, placebo-controlled study, 56 individuals with major depressive disorder were treated with curcumin (500 mg twice daily) or placebo for 8 weeks. The primary measure was the Inventory of Depressive Symptomatology self-rated version (IDS-SR30). Secondary outcomes included IDS-SR30 factor scores and the Spielberger State-Trait Anxiety Inventory (STAI). Results From baseline to week 4, both curcumin and placebo were associated with improvements in IDS-SR30 total score and most secondary outcome measures. From weeks 4 to 8, curcumin was significantly more effective than placebo in improving several mood-related symptoms, demonstrated by a significant group x time interaction for IDS-SR30 total score (F 1, 53=4.22, p=.045) and IDS-SR30 mood score (F 1, 53=6.51, p=.014), and a non-significant trend for STAI trait score (F1, 48=2.86, p=.097). Greater efficacy from curcumin treatment was identified in a subgroup of individuals with atypical depression. Conclusions Partial support is provided for the antidepressant effects of curcumin in people with major depressive disorder, evidenced by benefits occurring 4 to 8 weeks after treatment. Limitations Investigations with larger sample sizes, over extended treatment periods, and with varying curcumin dosages are required. © 2014 Elsevier B.V.

Wongnate T.,Mahidol University | Surawatanawong P.,Mahidol University | Visitsatthawong S.,Mahidol University | Sucharitakul J.,Chulalongkorn University | And 2 more authors.
Journal of the American Chemical Society | Year: 2014

Determination of the mechanism of dioxygen activation by flavoenzymes remains one of the most challenging problems in flavoenzymology for which the underlying theoretical basis is not well understood. Here, the reaction of reduced flavin and dioxygen catalyzed by pyranose 2-oxidase (P2O), a flavoenzyme oxidase that is unique in its formation of C4a-hydroperoxyflavin, was investigated by density functional calculations, transient kinetics, and site-directed mutagenesis. Based on work from the 1970s-1980s, the current understanding of the dioxygen activation process in flavoenzymes is believed to involve electron transfer from flavin to dioxygen and subsequent proton transfer to form C4a-hydroperoxyflavin. Our findings suggest that the first step of the P2O reaction is a single electron transfer coupled with a proton transfer from the conserved residue, His548. In fact, proton transfer enhances the electron acceptor ability of dioxygen. The resulting ·OOH of the open-shell diradical pair is placed in an optimal position for the formation of C4a-hydroperoxyflavin. Furthermore, the C4a-hydroperoxyflavin is stabilized by the side chains of Thr169, His548, and Asn593 in a "face-on" configuration where it can undergo a unimolecular reaction to generate H 2O2 and oxidized flavin. The computational results are consistent with kinetic studies of variant forms of P2O altered at residues Thr169, His548, and Asn593, and kinetic isotope effects and pH-dependence studies of the wild-type enzyme. In addition, the calculated energy barrier is in agreement with the experimental enthalpy barrier obtained from Eyring plots. This work revealed new insights into the reaction of reduced flavin with dioxygen, demonstrating that the positively charged residue (His548) plays a significant role in catalysis by providing a proton for a proton-coupled electron transfer in dioxygen activation. The interaction around the N5-position of the C4a-hydroperoxyflavin is important for dictating the stability of the intermediate. © 2013 American Chemical Society.

Lodi G.,University of Milan | Carrozzo M.,Northumbria University | Furness S.,University of Manchester | Thongprasom K.,Chulalongkorn University
British Journal of Dermatology | Year: 2012

Oral lichen planus (OLP) is a common chronic inflammatory disease associated with cell-mediated immunological dysfunction. Symptomatic OLP is painful and complete healing is rare. The aim of this review was to assess the evidence for the efficacy and safety of treatments for symptomatic OLP. The Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched in January 2011 to identify all randomized controlled trials (RCTs) evaluating any intervention for the treatment of symptomatic OLP. A total of 28 trials were included in this Cochrane review. There was no evidence from three RCTs that topical pimecrolimus is better than placebo in reducing pain from OLP. There was weak evidence from two RCTs that topical aloe vera may be associated with a reduction in pain compared with placebo. There was weak and unreliable evidence from two small trials, at high risk of bias, that topical ciclosporin may reduce pain and clinical signs of OLP. There was no evidence (from five trials each evaluating a different steroid and/or calcineurin inhibitor) that there is a difference between treatment with topical corticosteroids (TCSs) compared with topical calcineurin inhibitors with regard to reducing pain associated with OLP or that any specific steroid therapy is more or less effective at reducing pain. Although TCSs are considered to be the first-line treatment, we did not identify any RCTs that compared TCSs with placebo in patients with symptomatic OLP. From the 28 trials included in this systematic review, the wide range of interventions compared means there is insufficient evidence to support the superior effectiveness of any specific treatment. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

Puschmann A.,Lund University | Puschmann A.,Skåne University Hospital | Bhidayasiri R.,Chulalongkorn University | Weiner W.J.,University of Maryland Baltimore County
Parkinsonism and Related Disorders | Year: 2012

Accumulation of alpha-synuclein is a pathological feature in several neurological diseases. Its characterization has allowed for a re-grouping of diseases according to the expected pathology. The clinical syndrome of PD can now be classified into forms with and without alpha-synuclein pathology. DLB and PDD are synucleinopathies, and MSA shows alpha-synuclein pathology with glial inclusions. ADHD symptoms commonly occur in persons that will subsequently develop DLB. A similar phenomenon may be the early personality changes and frontotemporal atrophy in patients with SNCA multiplication. RLS is not known to have alpha-synuclein pathology, but as PD and ADHD, involves a hypodopaminergic state. Furthermore, PD and RLS co-occur in families in a way that suggests common inheritance. A proportion of patients with ET have brainstem Lewy body pathology. Gaucher disease and other lysosomal storage disorders also have alpha-synuclein pathology. Alpha-synuclein is a naturally unfolded protein. Non-fibrillar oligomeres may be the toxic species, and Lewy body formation may in fact be protective. Inhibiting alpha-synuclein toxicity seems to be an attractive novel treatment strategy and several approaches are being developed. When such treatments become available, clinicians will need to be familiar with the clinical features that distinguish the synucleinopathies from their look-alikes. © 2011 Elsevier Ltd. All rights reserved.

Thipwiwatpotjana P.,Chulalongkorn University | Lodwick W.A.,University of Colorado at Denver
Fuzzy Sets and Systems | Year: 2013

Random sets and probability intervals could be represented as uncertain parameters in a linear program. However, they are not the same. This paper presents a method by which an intersection of random sets provides an approximation of a given probability interval. Two specific random sets generating this approximation are used to construct probability density mass functions that provide the smallest and the largest expected values with respect to the probability interval uncertainty. We show that our construction is computationally more efficient than computing directly from probability intervals. These results are applied to linear programs with random set and probability interval uncertainties to obtain optimal solutions with respect to pessimistic, optimistic, and minimax regret approaches. © 2013 Elsevier B.V.

Baccaglini L.,University of Nebraska Medical Center | Thongprasom K.,Chulalongkorn University | Carrozzo M.,Northumbria University | Bigby M.,Beth Israel Deaconess Medical Center
Oral Diseases | Year: 2013

Lichen planus (LP) is a common disorder affecting the oral cavity (OLP) and skin. Despite intensive research, LP/OLP etiology and treatment remain controversial. We investigated four controversial topics: (i) Is hepatitis C virus (HCV) infection associated with LP and involved in its pathogenesis? (ii) Should all patients with LP be screened for HCV? (iii) Should patients with OLP have all their amalgam restorations removed? (iv) Are there any new treatments for OLP? Results from extensive literature searches suggested that: (i) Robust evidence from three meta-analyses indicate that HCV is associated with LP and might be involved in OLP pathogenesis (ii) It would be prudent to screen patients with LP/OLP at significant risk with an ELISA for HCV antibodies using country-specific screening strategies (iii) There is no evidence that either OLP or oral lichenoid lesions patients would routinely benefit from having all their amalgam restorations replaced. Weak evidence from potentially very biased, small, non-randomized, unblinded studies suggests that a small fraction of patients may benefit from targeted amalgam replacement. (iv) There is weak evidence that, among new OLP treatments, topical pimecrolimus, aloe vera, and oral curcuminoids may be useful. The development of specific formulations for oral delivery of topical medications is a promising field. © 2012 John Wiley & Sons A/S.

Agency: European Commission | Branch: H2020 | Program: RIA | Phase: BG-03-2014 | Award Amount: 6.76M | Year: 2015

TASCMAR project aspires to develop new tools and strategies in order to overcome existing bottlenecks in the biodiscovery and industrial exploitation of novel marine derived biomolecules (secondary metabolites and enzymes) with applications in the pharmaceuticals, nutraceuticals, cosmeceuticals and fine chemicals industries. Exploitation of neglected and underutilized marine invertebrates and symbionts from mesophotic zone will be combined with innovative approaches for the cultivation and extraction of marine organisms from lab to pilot-scale, using the unique prototypes Platotex and Zippertex, both reaching the Technology Readiness Level 7. Thus, marine dedicated cultivation and extraction equipment will be built and validated. These unique improvements will ensure sustainable supply of biomass and promote the production of high added value bioactive marine compounds. An integrated, holistic technological metabolomic approach will be applied, in conjunction with bioactivity profiling, as filtering and bio-prioritisation tools. Moreover, state-of-the-art analytical instrumentation and in-house databases will be employed for the dereplication and characterization of valuable compounds. A panel of libraries (marine organisms, extracts, pure metabolites and biocatalysts) will be constructed and exploited throughout the project. A focused panel of in-vitro, cell-based, in-ovo and in-vivo bioassays for discovering metabolites with anti-ageing and/or angiogenesis modulating activity will frame the entire work-flow and will reveal the lead compounds. In addition, the catalytic potential of mesophotic symbionts and deriving enzymes candidates will be evaluated in fine chemicals and bioremediation industries. The project activities will be constantly assessed via effective management for their societal, economical and environmental impact in order to find the best compromise between industrial development and sustainable growth.

Chuanchuen R.,Chulalongkorn University | Schweizer H.P.,Colorado State University
International Journal of Antimicrobial Agents | Year: 2012

Global gene transcription was assessed by microarray experiments following treatment of a triclosan-susceptible Δ(mexAB-oprM) Pseudomonas aeruginosa strain with subinhibitory concentrations of triclosan. Expression patterns of selected genes were verified by quantitative real-time PCR analysis. The results showed that triclosan exposure had a profound effect on gene expression, affecting 44% of the genes present on the Affymetrix GeneChip®, with 28% of genes being significantly upregulated and 16% being significantly downregulated in triclosan-treated cells. Genes encoding membrane proteins, transporters of small molecules, aspects of amino acid metabolism, and transcriptional regulators were significantly over-represented among the more strongly upregulated or downregulated genes in triclosan-treated cells. Quorum sensing-regulated genes were among the most strongly downregulated genes, presumably because of decreased acyl-acyl carrier protein pools and the resulting reduced acyl-homoserine lactone molecule synthesis. Surprisingly, iron homeostasis was completed perturbed in triclosan-exposed cells, with iron acquisition systems being strongly downregulated and iron storage systems significantly upregulated, thus mimicking conditions of excess iron. The profound perturbations of cellular metabolism via specific and global mechanisms may explain why triclosan is such a potent antimicrobial in susceptible bacteria. © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Dungchai W.,Chulalongkorn University | Chailapakul O.,Chulalongkorn University | Henry C.S.,Colorado State University
Analyst | Year: 2011

Wax screen-printing as a low-cost, simple, and rapid method for fabricating paper-based microfluidic devices (μPADs) is reported here. Solid wax was rubbed through a screen onto paper filters. The printed wax was then melted into the paper to form hydrophobic barriers using only a hot plate. We first studied the relationship between the width of a hydrophobic barrier and the width of the original design line. We also optimized the heating temperature and time and determined the resolution of structures fabricated using this technique. The minimum width of hydrophilic channel and hydrophobic barrier is 650 and 1300 μm, respectively. Next, our fabrication method was compared to a photolithographic method using the reaction between bicinchoninic acid (BCA) and Cu1+ to demonstrate differences in background reactivity. Photolithographically defined channels exhibited a high background while wax printed channels showed a very low background. Finally, the utility of wax screen-printing was demonstrated for the simultaneous determination of glucose and total iron in control human serum samples using an electrochemical method with glucose oxidase and a colorimetric method with 1,10-phenanthroline. This study demonstrates that wax screen-printing is an easy-to-use and inexpensive alternative fabrication method for μPAD, which will be especially useful in developing countries. © The Royal Society of Chemistry.

Pojanavaraphan T.,Chulalongkorn University | Schiraldi D.A.,Case Western Reserve University | Magaraphan R.,Chulalongkorn University
Applied Clay Science | Year: 2010

Montmorillonite (Na+-MMT) aerogel/prevulcanized natural rubber (PNR) composites were produced by freezing-drying. The composites exhibited densities in the range of 0.36-0.51gcm-3, which was in good agreement with the content of polymer in the aqueous solutions. The dispersion of the Na+-MMT particles and the microstructure of the composites were investigated by X-ray diffraction and scanning electron microcopy. The influence of the Na+-MMT particles on the mechanical, rheological and swelling properties of the composites was investigated. A composite made from 7 parts per hundred of rubber (phr) of Na+-MMT showed the greatest improvement in material properties. Such Na+-MMT aerogel/polymer composites will be candidates for structural and insulation applications. © 2010 Elsevier B.V.

Chuengsamarn S.,Srinakharinwirot University | Chuengsamarn S.,Brigham and Women's Hospital | Rattanamongkolgul S.,Srinakharinwirot University | Luechapudiporn R.,Chulalongkorn University | And 3 more authors.
Diabetes Care | Year: 2012

OBJECTIVE - To assess the efficacy of curcumin in delaying development of type 2 diabetes mellitus (T2DM) in the prediabetic population. RESEARCH DESIGN AND METHODS - This randomized, double-blinded, placebo-controlled trial included subjects (n = 240) with criteria of prediabetes. All subjects were randomly assigned to receive either curcumin or placebo capsules for 9months. To assess the T2DM progression after curcumin treatments and to determine the number of subjects progressing to T2DM, changes in β-cell functions (homeostasis model assessment [HOMA]-β, C-peptide, and proinsulin/insulin), insulin resistance (HOMA-IR), anti-inflammatory cytokine (adiponectin), and other parameters were monitored at the baseline and at 3-, 6-, and 9-month visits during the course of intervention. RESULTS - After 9 months of treatment, 16.4% of subjects in the placebo group were diagnosed with T2DM, whereas none were diagnosed with T2DM in the curcumin-treated group. In addition, the curcumin-treated group showed a better overall function of β-cells, with higher HOMA-β (61.58 vs. 48.72; P < 0.01) and lower C-peptide (1.7 vs. 2.17; P < 0.05). The curcumin-treated group showed a lower level of HOMA-IR (3.22 vs. 4.04; P < 0.001) and higher adiponectin (22.46 vs. 18.45; P < 0.05) when compared with the placebo group. CONCLUSIONS - A 9-month curcumin intervention in a prediabetic population significantly lowered the number of prediabetic individuals who eventually developed T2DM. In addition, the curcumin treatment appeared to improve overall function of β-cells, with very minor adverse effects. Therefore, this study demonstrated that the curcumin intervention in a prediabetic population may be beneficial. © 2012 by the American Diabetes Association.

Wongsawaeng D.,Chulalongkorn University | Wongsawaeng D.,General Atomics
Journal of Nuclear Materials | Year: 2010

The effects of design choices for the TRISO particle fuel were explored in order to determine their contribution to attaining high-burnup in Deep Burn modular helium reactor fuels containing transuranics from light water reactor spent fuel. The new design features were: (1) ZrC coating substituted for the SiC, allowing the fuel to survive higher accident temperatures; (2) pyrocarbon/SiC "alloy" substituted for the inner pyrocarbon coating to reduce layer failure and (3) pyrocarbon seal coat and thin ZrC oxygen getter coating on the kernel to eliminate CO. Fuel performance was evaluated using General Atomics Company's PISA code. The only acceptable design has a 200-μm kernel diameter coupled with at least 150-μm thick, 50% porosity buffer, a 15-μm ZrC getter over a 10-μm pyrocarbon seal coat on the kernel, an alloy inner pyrocarbon, and ZrC substituted for SiC. The code predicted that during a 1600 °C postulated accident at 70% FIMA, the ZrC failure probability is <10-4. © 2009 Elsevier B.V. All rights reserved.

Hunsom M.,Fuels Research Center | Hunsom M.,Chulalongkorn University | Saila P.,Fuels Research Center
Renewable Energy | Year: 2015

The enrichment of crude glycerol (29.8wt.%) from a biodiesel production plant and its subsequent electrochemical conversion under a galvanostatic mode to added-value compounds was successfully performed at a laboratory scale. The optimal solvent-extraction based enrichment of the crude glycerol, after the acid pre-treatment to remove most free fatty acids and salts, was found using n-propanol:pre-treated crude glycerol at volume ratio of 2, attaining 97.9% glycerol. The effects of the initial glycerol solution pH (1, 7 or 11), type of electrode (platinum (Pt), titanium-coated ruthenium oxide (Ti/RuO2) or stainless steel (SS)) and applied current density (0.08-0.27A/cm2) were explored. Using a galvanostatic mode, the enriched crude glycerol could be converted to added-value products, such as ethylene glycol, acetol, glycidol, acrolein, 1,2-propanediol (PD) and 1,3-PD. A Pt electrode, initial glycerol solution pH of 1 and current density of 0.14A/cm2 were found to be optimal giving a complete conversion of 0.3M glycerol within 14h with a total product yield of 68.7%. However, each specific product had a different optimal applied current density and electrolysis time. Finally, a simplified diagram showing the possible major reaction pathways of glycerol conversion by this electrochemical conversion over a Pt electrode was presented. © 2014 Elsevier Ltd.

Dungchai W.,Chulalongkorn University | Chailapakul O.,Chulalongkorn University | Henry C.S.,Colorado State University
Analytica Chimica Acta | Year: 2010

We report here the use of multiple indicators for a single analyte for paper-based microfluidic devices (μPAD) in an effort to improve the ability to visually discriminate between analyte concentrations. In existing μPADs, a single dye system is used for the measurement of a single analyte. In our approach, devices are designed to simultaneously quantify analytes using multiple indicators for each analyte improving the accuracy of the assay. The use of multiple indicators for a single analyte allows for different indicator colors to be generated at different analyte concentration ranges as well as increasing the ability to better visually discriminate colors. The principle of our devices is based on the oxidation of indicators by hydrogen peroxide produced by oxidase enzymes specific for each analyte. Each indicator reacts at different peroxide concentrations and therefore analyte concentrations, giving an extended range of operation. To demonstrate the utility of our approach, the mixture of 4-aminoantipyrine and 3,5-dichloro-2-hydroxy-benzenesulfonic acid, o-dianisidine dihydrochloride, potassium iodide, acid black, and acid yellow were chosen as the indicators for simultaneous semi-quantitative measurement of glucose, lactate, and uric acid on a μPAD. Our approach was successfully applied to quantify glucose (0.5-20. mM), lactate (1-25. mM), and uric acid (0.1-7. mM) in clinically relevant ranges. The determination of glucose, lactate, and uric acid in control serum and urine samples was also performed to demonstrate the applicability of this device for biological sample analysis. Finally results for the multi-indicator and single indicator system were compared using untrained readers to demonstrate the improvements in accuracy achieved with the new system. © 2010 Elsevier B.V.

Jongwutiwes S.,Chulalongkorn University | Putaporntip C.,Chulalongkorn University | Hughes A.L.,University of South Carolina
Vaccine | Year: 2010

A number of cell surface antigens of the infective stages of malaria parasites (genus Plasmodium) have been proposed as vaccine candidates, but high levels of polymorphism at the loci encoding these antigens are problematic for vaccine effectiveness. In order to test for the effects of anti-malarial control measures (including drugs and vector control) on polymorphism at antigen-encoding loci, we analyzed sequences of four antigen-encoding loci from P. vivax and two from P. falciparum collected in 2006-2007 from two areas of Thailand: (1) the NW, where malaria cases have remained high until recently; and (2) the South, where control measures have caused a dramatic decline in numbers of cases since 1990. Polymorphism in non-repeat regions of antigen-encoding loci was dramatically reduced in the South compared to the NW. These results suggest a two-pronged strategy for malaria eradication: (1) strenuous non-vaccine control measures that will cause a severe population bottleneck in the parasite; and (2) a subsequent local vaccine focused on one or a few locally occurring alleles at antigen-encoding loci. © 2010 Elsevier Ltd. All rights reserved.

Putaporntip C.,Chulalongkorn University | Hughes A.L.,University of South Carolina | Jongwutiwes S.,Chulalongkorn University
PLoS ONE | Year: 2013

Background: The merozoite surface protein-1 (MSP-1) is a candidate target for the development of blood stage vaccines against malaria. Polymorphism in MSP-1 can be useful as a genetic marker for strain differentiation in malarial parasites. Although sequence diversity in the MSP-1 locus has been extensively analyzed in field isolates of Plasmodium falciparum and P. vivax, the extent of variation in its homologues in P. ovale curtisi and P. ovale wallikeri, remains unknown. Methodology/Principal Findings: Analysis of the mitochondrial cytochrome b sequences of 10 P. ovale isolates from symptomatic malaria patients from diverse endemic areas of Thailand revealed co-existence of P. ovale curtisi (n = 5) and P. ovale wallikeri (n = 5). Direct sequencing of the PCR-amplified products encompassing the entire coding region of MSP-1 of P. ovale curtisi (PocMSP-1) and P. ovale wallikeri (PowMSP-1) has identified 3 imperfect repeated segments in the former and one in the latter. Most amino acid differences between these proteins were located in the interspecies variable domains of malarial MSP-1. Synonymous nucleotide diversity (πS) exceeded nonsynonymous nucleotide diversity (πN) for both PocMSP-1 and PowMSP-1, albeit at a non-significant level. However, when MSP-1 of both these species was considered together, πS was significantly greater than πN (p<0.0001), suggesting that purifying selection has shaped diversity at this locus prior to speciation. Phylogenetic analysis based on conserved domains has placed PocMSP-1 and PowMSP-1 in a distinct bifurcating branch that probably diverged from each other around 4.5 million years ago. Conclusion/Significance: The MSP-1 sequences support that P. ovale curtisi and P. ovale wallikeri are distinct species. Both species are sympatric in Thailand. The low level of sequence diversity in PocMSP-1 and PowMSP-1 among Thai isolates could stem from persistent low prevalence of these species, limiting the chance of outcrossing at this locus.

Koesukwiwat U.,U.S. Department of Agriculture | Koesukwiwat U.,Chulalongkorn University | Lehotay S.J.,U.S. Department of Agriculture | Leepipatpiboon N.,Chulalongkorn University
Journal of Chromatography A | Year: 2011

We developed and evaluated a new method of low-pressure gas chromatography-tandem mass spectrometry (LP-GC/MS-MS) using a triple quadrupole instrument for fast analysis of 150 relevant pesticides in four representative fruits and vegetables. This LP-GC (vacuum outlet) approach entails coupling a 10m, 0.53mm i.d., 1μm film analytical column between the MS transfer line and a 3m, 0.15mm i.d. capillary at the inlet. The MS creates a vacuum in the 10m analytical column, which reduces the viscosity of the He carrier gas and thereby shifts the optimal flow rate to greater velocity. By taking advantage of the H 2-like properties of He under vacuum, the short analytical column, a rapid oven temperature ramp rate, and the high selectivity and sensitivity of MS/MS, 150 pesticides were separated in <6.5min. The 2.5ms dwell time and 1ms interscan delay of the MS/MS instrument were critical for achieving >8 data points across the 2-3s wide peaks. To keep dwell and cycle times constant across all peaks, each segment consisted of 30 analytes (60 transitions). For assessment, we injected extracts of spiked broccoli, cantaloupe, lemon, and sweet potato from the updated QuEChERS sample preparation method. Average recoveries (n=72) were 70-120% for 144 of the pesticides, and reproducibilities were <20% RSD for all but 4 analytes. Also, detection limits were <5ng/g for all but a few pesticides, depending on the matrix. In addition to high quality performance, the method gave excellent reliability and high sample throughput, including easy peak integration to obtain rapid results. © 2011.

Pojanavaraphan T.,Chulalongkorn University | Magaraphan R.,Chulalongkorn University | Chiou B.-S.,U.S. Department of Agriculture | Schiraldi D.A.,Case Western Reserve University
Biomacromolecules | Year: 2010

Biodegradable foamlike materials based on a naturally occurring polymer (casein protein) and sodium montmorillonite clay (Na +-MMT) were produced through a simple freeze-drying process. By utilizing dl-glyceraldehyde (GC) as a chemical cross-linking agent, the structural integrity of these new aerogels were remarkably improved when compared to those of the control system (without GC), with a minimal increase in the density from 0.11 to 0.12 g cm -3. The degree of perfection of the foamlike structures was another parameter that had a significant influence on the physical and thermal performances of the low density composites. The biodegradability of the aerogels was investigated in terms of the carbon dioxide (CO 2) evolution for up to 8 weeks in compost media under controlled conditions. © 2010 American Chemical Society.

Rodthongkum N.,Chulalongkorn University | Ruecha N.,Chulalongkorn University | Rangkupan R.,Chulalongkorn University | Vachet R.W.,University of Massachusetts Amherst | Chailapakul O.,Chulalongkorn University
Analytica Chimica Acta | Year: 2013

A novel and highly sensitive electrochemical system based on electrospun graphene/polyaniline/polystyrene (G/PANI/PS) nanofiber-modified screen-printed carbon electrodes has been developed for dopamine (DA) determination. A dramatic increase (9 times) in the current signal for the redox reaction of a standard, ferri/ferrocyanide [Fe(CN)6]3-/4- couple was found when compared to an unmodified electrode. This modified electrode also exhibited favorable electron transfer kinetics and excellent electrocatalytic activity toward the oxidation of DA. When used together with square wave voltammetry (SWV), DA can be selectively determined in the presence of the common interferents (i.e. ascorbic acid and uric acid). Under optimal conditions, a very low limit of detection (0.05nM) and limit of quantification (0.30nM) were achieved for DA. In addition, a wide dynamic range of 0.1nM to 100μM was found for this electrode system. Finally, the system can be successfully applied to determine DA in complex biological environment (e.g. human serum, urine) with excellent reproducibility. © 2013 Elsevier B.V.

Sangphech N.,Chulalongkorn University | Osborne B.A.,University of Massachusetts Amherst | Palaga T.,Chulalongkorn University
Immunobiology | Year: 2014

Macrophages play critical roles in innate immune defense by sensing microbes using pattern-recognition receptors. Lipopolysaccharide (LPS) stimulates macrophages via TLR, which leads to activation of downstream signaling cascades. In this study, we investigated the roles of a conserved signaling pathway, Notch signaling, in regulating the downstream signaling cascades of the LPS/TLR4 pathways in macrophages. Using a phospho-proteomic approach and a gamma-secretase inhibitor (GSI) to suppress the processing and activation of Notch signaling, we identified regulator of G protein signaling 19 (RGS19) as a target protein whose phosphorylation was affected by GSI treatment. RGS19 is a guanosine triphosphatase (GTPase)-activating protein that functions to negatively regulate G protein-coupled receptors via Gαi/Gαq-linked signaling. Stimulation of RAW264.7 cells with LPS increased the level of the phosphorylated form of RGS19, while LPS stimulation in the presence of GSI decreased its level. GSI treatment did not alter the mRNA level of rgs19. Treatment with GSI or silencing of rgs19 in macrophages impaired the phosphorylation of Akt Thr308 upon LPS stimulation. Furthermore, targeted deletion of a DNA-binding protein and binding partner of the Notch receptor, RBP-Jκ/CSL, in macrophages resulted in delayed and decreased Akt phosphorylation. Because the PI3K/Akt pathway regulates cell survival in various cell types, the cell cycle and cell death were assayed upon GSI treatment, phosphatidylinositol 3 kinase (PI3K) inhibitor treatment or silencing of rgs19. GSI treatment resulted in decreased cell populations in the G1 and S phases, while it increased the cell population of cell death. Similarly, silencing of rgs19 resulted in a decreased cell population in the G1 phase and an increased cell population in the subG1 phase. Inhibition of Akt phosphorylation by PI3K inhibitor in LPS-stimulated macrophages increased cell population in G1 phase, suggesting a possible cell cycle arrest. Taken together, these results indicate that Notch signaling positively regulates phosphorylation of Akt, possibly via phosphorylation of RGS19, and inhibition of both molecules affects the cell survival and cell cycle of macrophages upon LPS stimulation. © 2014 Elsevier GmbH.

Apilux A.,Chulalongkorn University | Dungchai W.,Chulalongkorn University | Siangproh W.,Srinakharinwirot University | Praphairaksit N.,Chulalongkorn University | And 2 more authors.
Analytical Chemistry | Year: 2010

A novel lab-on-paper device combining electrochemical and colorimetric detection for the rapid screening of Au(III) in the presence of a common interference, Fe(III), in industrial waste solutions is presented here. With dilute aqua regia (0.1 M HCl + 0.05 M HNO3) as the supporting electrolyte, square wave voltammetry on paper provided a well-defined reduction peak for Au(III) at ∼287 ± 12 mV vs Ag/AgCl. Under the optimized working conditions, the calibration curve showed good linearity in the concentration range of 1-200 ppm of Au(III) with a correlation coefficient of 0.997. The limit of detection (LOD) of the proposed method is 1 ppm. Interferences from various cations were also studied. Fe(III) is the only metal that affects the electrochemical determination of Au(III) when present above a 2.5-fold excess concentration of that of the Au(III). To overcome this limitation, a colorimetric method was used to simultaneously detect Fe(III) as a screening tool. The procedure was then successfully applied to determine Au(III) in gold-refining waste solutions. The results are in agreement with those obtained from inductively coupled plasma-atomic emission spectrometry (ICP-AES). © 2010 American Chemical Society.

Pauwels R.,Chulalongkorn University | Araki K.,Showa University | Siewerdsen J.H.,Johns Hopkins University | Thongvigitmanee S.S.,Biomedical Imaging Center
Dentomaxillofacial Radiology | Year: 2015

As CBCT is widely used in dental and maxillofacial imaging, it is important for users as well as referring practitioners to understand the basic concepts of this imaging modality. This review covers the technical aspects of each part of the CBCT imaging chain. First, an overview is given of the hardware of a CBCT device. The principles of cone beam image acquisition and image reconstruction are described. Optimization of imaging protocols in CBCT is briefly discussed. Finally, basic and advanced visualization methods are illustrated. Certain topics in these review are applicable to all types of radiographic imaging (e.g. the principle and properties of an X-ray tube), others are specific for dental CBCT imaging (e.g. advanced visualization techniques). © 2015 The Authors.

Koesukwiwat U.,U.S. Department of Agriculture | Koesukwiwat U.,Chulalongkorn University | Lehotay S.J.,U.S. Department of Agriculture | Miao S.,Shanghai Institute for Food and Drug Control | Leepipatpiboon N.,Chulalongkorn University
Journal of Chromatography A | Year: 2010

A higher monitoring rate is highly desirable in the labs, but this goal is typically limited by sample throughput. In this study, we sought to assess the real-world applicability of fast, low-pressure GC-time-of-flight MS (LP-GC/TOFMS) for the identification and quantification of 150 pesticides in tomato, strawberry, potato, orange, and lettuce samples. Buffered and unbuffered versions of QuEChERS (which stands for " quick, easy, cheap, effective, rugged, and safe" ) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for clean-up were compared for sample preparation. For clean-up of all sample types, a combination of 150mg MgSO4, 50mg primary secondary amine (PSA), 50mg C18, and 7.5mg graphitized carbon black (GCB) per mL extract was used. No significant differences were observed in the results between the different sample preparation versions. QuEChERS took <10min per individual sample, or <1h for two chemists to prepare 32 pre-homogenized samples, and using LP-GC/TOFMS, <10min run time and <15min cycle time allowed >32 injections in 8h. Overall, >126 analytes gave recoveries (3 spiking levels) in the range of 70-120% with <20% RSD. The results indicate that LP-GC/TOFMS for GC-amenable analytes matches UHPLC-MS/MS in terms of sample throughput and turnaround time for their routine, concurrent use in the analysis of a wide range of analytes in QuEChERS extracts to achieve reliable quantification and identification of pesticide residues in foods. © 2010.

Puangpetch T.,Silpakorn University | Sommakettarin P.,Chulalongkorn University | Chavadej S.,Chulalongkorn University | Sreethawong T.,Chulalongkorn University
International Journal of Hydrogen Energy | Year: 2010

The photocatalytic water splitting is a promising process for producing H2 from two abundant renewable sources of water and solar light, with the aid of a suitable photocatalyst. In this work, a combination of sensitizer addition and noble metal loading was employed to modify perovskite photocatalysts in order to achieve the enhancement of photocatalytic H 2 production under visible light irradiation. The dependence of the H2 production on type of mesoporous-assembled perovskite titanate nanocrystal photocatalysts (MgTiO3, CaTiO3, and SrTiO 3), calcination temperature of photocatalyst, Pt loading, type and concentration of electron donor (diethanolamine, DEA; and triethanolamine, TEA), concentration of sensitizer (Eosin Y, E.Y.), photocatalyst dosage, and initial solution pH, was systematically studied. The experimental results showed that the 0.5 wt.% Pt-loaded mesoporous-assembled SrTiO3 nanocrystal synthesized by a single-step sol-gel method and calcined at 650 °C exhibited the highest photocatalytic H2 production activity from a 15 vol% DEA aqueous solution with dissolved 0.5 mM E.Y. Moreover, the optimum photocatalyst dosage and initial solution pH for the maximum photocatalytic H2 production activity were found to be 6 g/l and 11.6, respectively. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

Samart C.,Thammasat University | Chaiya C.,Rajamangala University of Technology at Krungthep | Reubroycharoen P.,Chulalongkorn University
Energy Conversion and Management | Year: 2010

The transesterification of soybean oil with a CaO/mesoporous silica catalyst was achieved. The effects of CaO loading levels in the mesoporous silica catalyst, the amount of catalyst to substrate level and the reaction temperature and time on the conversion of soybean oil were investigated. Increasing the temperature and reaction time raised the total conversion of soybean oil attained. The optimized condition, found to be 15 wt.% of Ca loading on the mesoporous silica catalyst, a 5% (w/w) catalyst to oil level and a reaction temperature of 60 °C for 8 h, provided the highest yield of 95.2%. The fuel properties of the biodiesel obtained under these optimized conditions were acceptable under the biodiesel standards of Thailand. © 2010 Elsevier Ltd. All rights reserved.

Talchai C.,Columbia University | Talchai C.,Chulalongkorn University | Xuan S.,Columbia University | Kitamura T.,Gunma University | And 2 more authors.
Nature Genetics | Year: 2012

Restoration of regulated insulin secretion is the ultimate goal of therapy for type 1 diabetes. Here, we show that, unexpectedly, somatic ablation of Foxo1 in Neurog3 + enteroendocrine progenitor cells gives rise to gut insulin-positive (Ins +) cells that express markers of mature β cells and secrete bioactive insulin as well as C-peptide in response to glucose and sulfonylureas. Lineage tracing experiments showed that gut Ins + cells arise cell autonomously from Foxo1-deficient cells. Inducible Foxo1 ablation in adult mice also resulted in the generation of gut Ins + cells. Following ablation by the β-cell toxin streptozotocin, gut Ins + cells regenerate and produce insulin, reversing hyperglycemia in mice. The data indicate that Neurog3 + enteroendocrine progenitors require active Foxo1 to prevent differentiation into Ins + cells. Foxo1 ablation in gut epithelium may provide an approach to restore insulin production in type 1 diabetes. © 2012 Nature America, Inc. All rights reserved.

Masomboon N.,Chulalongkorn University | Ratanatamskul C.,Chulalongkorn University | Lu M.-C.,Chia Nan University of Pharmacy and Science
Journal of Hazardous Materials | Year: 2011

The kinetics of 2,6-dimethylaniline degradation by Fenton process, electro-Fenton process and photoelectro-Fenton process was investigated. This study attempted to eliminate the potential interferences from intermediates by making a kinetics comparison of Fenton, electro-Fenton and photoelectro-Fenton methods through use initial rate techniques during the first 10min of the reaction. Exactly how the initial concentration of 2,6-dimethylaniline, ferrous ions and hydrogen peroxide affects 2,6-dimethylaniline degradation was also examined. Experimental results indicate that the 2,6-dimethylaniline degradation in the photoelectro-Fenton process is superior to the ordinary Fenton and electro-Fenton processes. Additionally, for 100% removal of 1mM 2,6-dimethylaniline, the supplementation of 1mM of ferrous ion, 20mM of hydrogen peroxide, current density at 15.89Am -2 and 12 UVA lamps at pH 2 was necessary. The overall rate equations for 2,6-dimethylaniline degradation by Fenton, electro-Fenton and photoelectro-Fenton processes were proposed as well. © 2011 Elsevier B.V.

Masomboon N.,Chulalongkorn University | Ratanatamskul C.,Chulalongkorn University | Lu M.-C.,Chia Nan University of Pharmacy and Science
Journal of Hazardous Materials | Year: 2010

Oxidation of 2,6-dimethylaniline by electro-Fenton process in acidic solution at pH 2 was investigated. The effects of pH, Fe2+, H2O2 and current density were assessed to determine the optimum operating parameters. The oxidation efficiency of 2,6-dimethylaniline was determined by the reduction of 2,6-dimethylaniline, COD and TOC in the solutions. Results reveal that 1 mM of 2,6-dimethylaniline can be completely degraded in 4 h with 1 mM of Fe2+ and 20 mM of H2O2 and current density of 15.89 A m-2 at pH 2. The highest COD and TOC removal were observed when 120 mM of hydrogen peroxide was applied. Consequently, the electro-Fenton process is a reliable alternative in the degradation of 2,6-dimethylaniline. 2,6-dimethylphenol, 2,6-dimethylnitrobenzene, 2,6-dimethylbenzoquinone, 3-hexanone, lactic acid, oxalic acid, acetic acid, maleic acid and formic acid were detected during the degradation of 1 mM of 2,6-dimethylaniline solution by electro-Fenton method. A reaction pathway that includes these products is proposed for 2,6-dimethylaniline degradation. © 2009 Elsevier B.V. All rights reserved.

Mekasuwandumrong O.,Silpakorn University | Pawinrat P.,Chulalongkorn University | Praserthdam P.,Chulalongkorn University | Panpranot J.,Chulalongkorn University
Chemical Engineering Journal | Year: 2010

The effects of synthesis conditions (i.e., metal concentration, precursor flowrate, and O2 dispersion) during flame-spray pyrolysis (FSP) and annealing post-treatment on the characteristics and photocatalytic activities of ZnO nanoparticles have been investigated. The average particle size of ZnO powder prepared by one-step FSP method were in the range of 8.8-47.0nm and were found to be increased with increasing the enthalpy density, flame height, and high-temperature residence time during FSP synthesis. The larger particle size FSP-derived ZnO nanoparticles exhibited higher photocatalytic activities in the degradation of methylene blue (MB) dye. The degradation rate over FSP-ZnO-47.0nm was 1.7 and 7.2 times higher than those of the commercially available photocatalysts Degussa P-25 and JRC-TiO2, respectively. The better photocatalytic performance of the FSP-ZnO was correlated well with the improved crystalline quality of ZnO nanoparticles as revealed by the X-ray diffraction (XRD) and the photoluminescence (PL) results. Further increase of FSP-ZnO particle size to 52.6-103.5nm by annealing post-treatment at high temperatures (750-900°C), however, gradually decreased their photocatalytic activities. Our results in this study suggest a balance between high crystalline quality that enhanced photo phenomena and the surface area available for substrate adsorption in order to obtain high photocatalytic activity of ZnO nanoparticles. © 2010 Elsevier B.V.

Homklin R.,Silpakorn University | Hongsriphan N.,Silpakorn University | Hongsriphan N.,Chulalongkorn University
Energy Procedia | Year: 2013

The influence of nucleating agents (nano-sized calcium carbonate and sodium benzoate) on mechanical and thermal properties of PLA/PBS co-continuous blends was investigated. PLA/PBS 60/40, 50/50, 40/60 wt% blends were compounded with NPCC or SB (0.5 and 1.0 phr) in a twin-screw extruder and fabricated into thin sheets by hot pressing. DSC was used to study glass transition temperature (Tg) and percentage of crystallinity (%Xc) of the blends. Morphology of fractured surface was examined using SEM. It is found that the PLA/PBS 50/50 wt% blend was cocontinuous structure even incorporating NPCC or SB of 0.5 and 1.0 phr. Adding SB of 1.0 phr caused the PLA dispersed phases in the PLA/PBS 40/60 wt% to be smaller droplets distributed in the continuous PBS matrix. On the other hand, adding NPCC of 1.0 phr into PLA/PBS 60/40 wt% produced elongated continuous phase of PBS stripped out of PLA matrix. Adding SB into PLA reduced Tg from 63 to 60 oC, while NPCC nucleated higher %X c of PLA phases in all blends. Tensile strength, elongation at break and energy at break of the blends were reduced when filled with NPCC and SB. This is due to increasing in crystallinity of the PLA phases and the presence of stress concentrators in the blends. © 2013 The Authors.

Mitranun W.,Chulalongkorn University | Deerochanawong C.,Rajvithi Hospital | Tanaka H.,University of Texas at Austin | Suksom D.,Chulalongkorn University
Scandinavian Journal of Medicine and Science in Sports | Year: 2014

To determine the effects of continuous aerobic exercise training (CON) vs interval aerobic exercise training (INT) on glycemic control and endothelium-dependent vasodilatation, 43 participants with type 2 diabetes were randomly allocated to the sedentary, CON, and INT groups. The CON and INT exercise training programs were designed to yield the same energy expenditure/exercise session and included walking on treadmill for 30 and 40min/day, 3 times/week for 12weeks. Body fatness and heart rate at rest decreased and leg muscle strength increased (all P<0.05) in both the CON and INT groups. Fasting blood glucose levels decreased (P<0.05) in both exercise groups but glycosylated hemoglobin levels decreased (P<0.05) only in the INT group. Maximal aerobic capacity, flow-mediated dilation, and cutaneous reactive hyperemia increased significantly in both exercise groups; however, the magnitude of improvements was greater in the INT group. Only the INT group experienced reductions in erythrocyte malondialdehyde and serum von Willebrand factor and increases in plasma glutathione peroxidase and nitric oxide (all P<0.05). We concluded that both continuous and interval training were effective in improving glycemic control, aerobic fitness, and endothelium-dependent vasodilation, but the interval training program appears to confer greater improvements than the continuous training program. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Adulpravitchai A.,Chulalongkorn University | Schmidt M.A.,University of New South Wales
Journal of High Energy Physics | Year: 2015

Abstract: Sterile Neutrinos with a mass in the keV range form a good candidate for dark matter. They are naturally produced from neutrino oscillations via their mixing with the active neutrinos. However the production via non-resonant neutrino oscillations has recently been ruled out. The alternative production via Higgs decay is negligibly small compared to neutrino oscillations. We show that in the neutrino-phillic two Higgs doublet model, the contribution from Higgs decay can dominate over the contribution from neutrino oscillations and evade all constraints. We also study the free-streaming horizon and find that a sterile neutrino mass in the range of 4 to 53 keV leads to warm dark matter. © 2015, The Author(s).

Buntem R.,Silpakorn University | Intasiri A.,Chulalongkorn University | Lueangchaichaweng W.,Silpakorn University
Journal of Colloid and Interface Science | Year: 2010

A novel metal ion sensor was prepared using silica monolith doped with meso-tetra(p-carboxyphenyl)porphyrin. The doped material was prepared using TEOS:EtOH:H2O:HCl:porphyrin molar ratios of 1:5:7:3.1×10-2:2.3×10-5, respectively. The mixture was kept 16days for the gelation process and then the wet gel was dried at 55-60°C for 3days. The porphyrin-doped monolith obtained was kept in 1M metal salt solution for 2days. The visible spectrum of the metal-coordinated porphyrin-doped monolith was compared with the uncoordinated porphyrin-doped monolith. The spectra show the characteristic maxima for Cu2+ at 543nm, for Zn2+ at 522, 559, and 596nm, for Pb2+ at 531 and 559nm, and for Ni2+ at 522 and 551nm. The metal coordinated to the silica monolith could be removed by washing with 1M HNO3. However the Cu2+ could not be eluted by acidic solution due to its strong bonding to the porphyrin. The results show that this porphyrin-doped monolithic biomaterial is a promising sensor for metal ions in wastewater and other harsh environments. © 2010.

Choedkiatsakul I.,Chulalongkorn University | Ngaosuwan K.,Rajamangala University of Technology at Krungthep | Assabumrungrat S.,Chulalongkorn University
Fuel Processing Technology | Year: 2013

This research investigated the application of commercial heterogeneous catalysts i.e., calcium oxide (CaO) and potassium phosphate (K 3PO4) for biodiesel production in an ultrasound-assisted reactor (US). For comparison, the results from the use of homogeneous catalysts i.e., sodium hydroxide (NaOH) and sulfuric acid (H2SO4) as well as from the use of conventional mechanical stirred reactor (MS) were also studied. High methyl ester yields were achieved in the US reactor for both CaO (90%) and K3PO4 (80%). The mixing characteristics generated from US and MS reactors resulted in the different performance (activation and deactivation) of CaO and K3PO4 catalyzed transesterification. The major overcome of using US reactor for heterogeneously catalyzed transesterification was found in the catalyst reusability test. Methyl ester yield of CaO catalyst gradually reduced when applying US reactor compared to MS reactor, particularly in the last cycle. The dissolution effect was more severe when employing K3PO4 catalyst in the MS reactor due to the mechanical stress and the mixing characteristic effects. Therefore, the use of US reactor did not only provide the high methyl ester yield in a short reaction time but also showed the hindrance of dissolution compared to the MS reactor. It can be concluded that the heterogeneously catalyzed transesterification in US reactor was not only favorable in the activation but also diminishable in the deactivation of solid catalysts. © 2013 Elsevier B.V.

Leepipatpiboon N.,Chulalongkorn University | Pancharoen U.,Chulalongkorn University | Ramakul P.,Silpakorn University
Korean Journal of Chemical Engineering | Year: 2013

The separation of cobalt(II) and nickel(II) ions by HFSLM has been presented. The feed solution is 0. 5M thiocyanate containing 300 ppm each of cobalt(II) and nickel(II) ions, whereas extractant is Alamine300 and the stripping solution is ammonia. Cobalt(II) is more preferable with Alamine300 than nickel(II). The effects of pH, Alamine300 concentration and ammonia concentration were investigated. Seven diluents were used: hexane, decanol, chlorobenzene, benzene, dichloromethane, ethylene dichloride and chloroform with different polarity indexes, from 0. 1-4. 1. Nickel(II) ion which is unpreferable with Alamine300 was used as a tracer to determine the membrane stability. The polarity of the diluents was found to be the main factor influencing the extraction performance and stability of a liquid membrane. The decreasing of polarity of the diluent can prolong the membrane stability, but the percentages of extraction and stripping decreased. The longest lifetime, 200 minutes, was obtained by using hexane as a diluent with the polarity index of 0. 1. © 2012 Korean Institute of Chemical Engineers, Seoul, Korea.

Aramwit P.,Bioactive Resources for Innovative Clinical Applications Research Unit | Siritienthong T.,Bioactive Resources for Innovative Clinical Applications Research Unit | Srichana T.,Sudan University of Science and Technology | Ratanavaraporn J.,Chulalongkorn University
Cells Tissues Organs | Year: 2013

Silk sericin has recently been studied for its advantageous biological properties, including its ability to promote wound healing. This study developed a delivery system to accelerate the healing of full-thickness wounds. Three-dimensional scaffolds were fabricated from poly(vinyl alcohol) (PVA), glycerin (as a plasticizer) and genipin (as a crosslinking agent), with or without sericin. The physical and biological properties of the genipin-crosslinked sericin/PVA scaffolds were investigated and compared with those of scaffolds without sericin. The genipin-crosslinked sericin/PVA scaffolds exhibited a higher compressive modulus and greater swelling in water than the scaffolds without sericin. Sericin also exhibited controlled release from the scaffolds. The genipin-crosslinked sericin/PVA scaffolds promoted the attachment and proliferation of L929 mouse fibroblasts. After application to full-thickness rat wounds, the wounds treated with genipin-crosslinked sericin/PVA scaffolds showed a significantly greater reduction in wound size, collagen formation and epithelialization compared with the control scaffolds without sericin but lower numbers of macrophages and multinucleated giant cells. These results indicate that the delivery of sericin from the novel genipin-crosslinked scaffolds efficiently healed the wound. Therefore, these genipin-crosslinked sericin/PVA scaffolds represent a promising candidate for the accelerated healing of full-thickness wounds. Copyright © 2013 S. Karger AG, Basel.

Monshupanee T.,University of Southern Denmark | Monshupanee T.,Chulalongkorn University | Johansen S.K.,University of Southern Denmark | Dahlberg A.E.,Brown University | Douthwaite S.,University of Southern Denmark
Molecular Microbiology | Year: 2012

The binding site of the cyclic peptide antibiotics capreomycin and viomycin is located on the ribosomal subunit interface close to nucleotides C1409 in 16S rRNA and C1920 in 23S rRNA. In Mycobacterium tuberculosis, the 2′-hydroxyls of both nucleotides are methylated by the enzyme TlyA. Loss of these methylations through inactivation of TlyA confers resistance to capreomycin and viomycin. We report here that TlyA orthologues occur in diverse bacteria and fall into two distinct groups. One group, now termed TlyAI, has shorter N- and C-termini and methylates only C1920; the second group (now TlyAII) includes the mycobacterial enzyme, and these longer orthologues methylate at both C1409 and C1920. Ribosomal subunits are the preferred substrates for both groups of orthologues. Amino acid substitutions at the N-terminus of TlyAII reduce its ability to methylate these substrates. Growing pairs of recombinant TlyAIIEscherichia coli strains in competition shows that even subtle changes in the level of rRNA methylation lead to significant differences in susceptibility to sub-inhibitory concentrations of capreomycin. The findings reveal that 2′-O-methyls at both C1409 and C1920 play a role in facilitating the inhibitory effects of capreomycin and viomycin on the bacterial ribosome. © 2012 Blackwell Publishing Ltd.

Heintze S.D.,RandD | Thunpithayakul C.,Chulalongkorn University | Armstrong S.R.,University of Iowa | Rousson V.,University of Lausanne
Dental Materials | Year: 2011

Objective: To determine if the results of resin-dentin microtensile bond strength (μTBS) is correlated with the outcome parameters of clinical studies on non-retentive Class V restorations. Methods: Resin-dentin μTBS data were obtained from one test center; the in vitro tests were all performed by the same operator. The μTBS testing was performed 8 h after bonding and after 6 months of storing the specimens in water. Pre-test failures (PTFs) of specimens were included in the analysis, attributing them a value of 1 MPa. Prospective clinical studies on cervical restorations (Class V) with an observation period of at least 18 months were searched in the literature. The clinical outcome variables were retention loss, marginal discoloration and marginal integrity. Furthermore, an index was formulated to be better able to compare the laboratory and clinical results. Estimates of adhesive effects in a linear mixed model were used to summarize the clinical performance of each adhesive between 12 and 36 months. Spearman correlations between these clinical performances and the μTBS values were calculated subsequently. Results: Thirty-six clinical studies with 15 adhesive/restorative systems for which μTBS data were also available were included in the statistical analysis. In general 3-step and 2-step etch-and-rinse systems showed higher bond strength values than the 2-step/3-step self-etching systems, which, however, produced higher values than the 1-step self-etching and the resin modified glass ionomer systems. Prolonged water storage of specimens resulted in a significant decrease of the mean bond strength values in 5 adhesive systems (Wilcoxon, p < 0.05). There was a significant correlation between μTBS values both after 8 h and 6 months of storage and marginal discoloration (r = 0.54 and r = 0.67, respectively). However, the same correlation was not found between μTBS values and the retention rate, clinical index or marginal integrity. Significance: As μTBS data of adhesive systems, especially after water storage for 6 months, showed a good correlation with marginal discoloration in short-term clinical Class V restorations, longitudinal clinical trials should explore whether early marginal staining is predictive for future retention loss in non-carious cervical restorations. © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Rungamornrat J.,Chulalongkorn University | Mear M.E.,University of Texas at Austin
International Journal for Numerical Methods in Engineering | Year: 2011

A weakly singular symmetric Galerkin boundary element method (SGBEM) is coupled with the standard finite element method (FEM) in order to establish an accurate and efficient numerical technique for analysis of fractures in three-dimensional, anisotropic, linearly elastic media. In the strategy, the weakly singular SGBEM developed by Rungamornrat and Mear (textitInt. J. Solids Struct. 2008; 45:1283-1301; Comput. Methods Appl. Mech. Engrg 2008; 197:4319-4332) is utilized to model a small-scale region containing the crack while the (possibly large and complex) compliment region is treated by the FEM. The coupled technique exploits the positive features of both methods; the SGBEM proves to be a convenient and highly accurate method for obtaining mixed-mode stress intensity factors along the crack front, whereas the FEM is very efficient for modeling large-scale problems in the absence of cracks. An important aspect of the formulation and implementation of the technique is that continuity of displacement and traction across the interface between the SGBEM and FEM regions is enforced in a weak sense. This allows the two regions (one modeled by the SGBEM and the other by the FEM) to be discretized independently without the need for the resulting meshes to conform on the interface separating the regions, and this flexibility in the discretization process leads to a significant reduction in the modeling effort. To demonstrate the utility and accuracy of the technique, several boundary value problems involving both embedded and surface breaking cracks are treated, and it is shown that the coupled technique yields highly accurate stress intensity factors that exhibit only a slight dependence upon mesh refinement. © 2010 John Wiley & Sons, Ltd.

Masomboon N.,Chulalongkorn University | Ratanatamskul C.,Chulalongkorn University | Lu M.-C.,Chia Nan University of Pharmacy and Science
Applied Catalysis A: General | Year: 2010

A new approach to promoting ferric reduction efficiency using electrochemical, photoreduction and photo-assisted electrochemical processes has been developed. The use of UVA irradiation and electric current as electron donors can efficiently initiate a Fenton reaction called the photoelectro-Fenton process. 2,6-Dimethylaniline was the target compound in this study. Parameters including initial pH, ferrous ion dosage, hydrogen peroxide concentration, the electric current applied and the number of UVA lamps used were investigated to evaluate the performance of the photoelectro-Fenton process. The removal efficiencies of 2,6-dimethylaniline, COD, TOC and initial degradation rate were determined in this study. The optimum condition for 1 mM of 2,6-dimethylaniline degradation was achieved when using 1 mM of ferrous ions, 20 mM of hydrogen peroxide at pH 2 and 2 A of electric current applied with four UVA lamps used. The energy cost, reaction mechanism and intermediates identification of 2,6-dimethylaniline degradation have also been determined in this study. © 2010 Elsevier B.V. All rights reserved.

OBJECTIVES: There is evidence that inflammatory, oxidative and nitrosative stress (IO&NS) pathways participate in the pathophysiology of a subgroup of patients with Myalgic Encephalomyelitis/chronic fatigue syndrome (ME/CFS). Increased IgM-related autoimmune responses to oxidative specific epitopes (OSEs), including malondialdehyde (MDA), oleic acid and phosphatidyl inositol (Pi), and nitroso-(NO)-adducts, including NO-tryptophan (NOW), NO-arginine and NO-cysteinyl, are frequently observed in ME/CFS. Autoimmune responses in ME/CFS may be driven by increased bacterial translocation as measured by IgM and IgA responses to LPS of gram negative bacteria. METHODS: The aim of this study is to examine whether IgM responses to OSEs and NO-adducts are related to a better outcome as measured by the Fibromyalgia and Fatigue Rating Scale (FF). 76 ME/CFS patients with initially abnormal autoimmune responses were treated with care-as-usual, including nutraceuticals with anti-IO&NS effects (NAIOS), such as L-carnitine, coenzyme Q10, taurine + lipoic acid, with or without curcumine + quercitine or N-acetyl-cysteine, zinc + glutamine. RESULTS: We found that use of these NAIOS was associated with highly significant reductions in initially increased IgM-mediated autoimmune responses to OSEs and NO-adducts. A greater reduction in autoimmune responses to OSEs during intake of these NAIOS was associated with a lower FF score. Reductions in IgM responses to oleic acid, MDA and Pi, but not in any of the NO-adducts, were associated with reductions in severity of illness. These associations remained significant after adjusting for possible effects of increased bacterial translocation (leaky gut). CO N - CLUSIONS: Our results show that autoimmune responses to OSEs are involved in the pathophysiology of ME/CFS and that these pathways are a new drug target in a subgroup of ME/CFS patients. Although hypernitrosylation and nitrosative stress play a role in ME/CFS, reductions in these pathways are not associated with lowered severity of illness. Randomized controlled trials with NAIOS should be carried out in the subgroup of ME/CFS patients with initially increased autoimmune responses to OSEs. © 2014 Neuroendocrinology Letters.

Jitkarnka S.,Chulalongkorn University
Chemical Engineering Transactions | Year: 2015

The catalytic dehydration of bio-ethanol is an effective route to transform alcohol to valuable hydrocarbons and chemicals such as olefins and aromatics. There are a variety of reactions that involve, after ethylene is formed as an intermediate, such as oligomerization, aromatization, and alkylation. Products can be, for examples, butylene, benzene, derivatives of benzene, and oxygenates. In this research, cobalt oxidepromoted alumina (Co3O4/γ-Al2O3) was examined, aiming to investigate the production of high valuable oxygenate compounds and hydrocarbons in bio-ethanol dehydration. The amount of Co loading was fixed at 5.0 %. The catalysts were characterized using SAA, XRD, and XPS, and tested in a fixed-bed reactor under atmospheric pressure at 500 °C for 8 h. Additionally, the gaseous products were analyzed using an on-line GC, and the oil products were analyzed using GCxGC-MS/TOF. With oxide loading, the amount of C9 and C10 + aromatics increased in the oil as ethylene decreased in the gas. The major components in the oil are oxygenate compounds, which consisted of ketones and alcohols such as 2-butanone, 2-pentanone, and phenol, together with hydrocarbons such as benzene, and a trace amount of p-xylene, ethyl-benzene, and naphthalene. The ratio of oxygenates and hydrocarbons was 19:1. Furthermore, XPS result indicated that Co3O4mainly existed on γ-Al2O3, and after use, some of Co3O4transformed to CoO. Copyright © 2015, AIDIC Servizi S.r.l.,.

Pataradool K.,Chulalongkorn University
Hand surgery : an international journal devoted to hand and upper limb surgery and related research : journal of the Asia-Pacific Federation of Societies for Surgery of the Hand | Year: 2011

Trigger finger is one of the most common upper extremity problems in the outpatient department. Conservative treatment is the mainstay for management of trigger digits especially steroid injection with highly satisfactory outcome and minimal complication. Conventional injection technique (CI) that approaches flexor tendon sheath over metacarpal head directly causes pain for most patients. The proximal phalanx injection technique (P1I) at palmar surface of midproximal phalanx is simple and less painful for the patients. We compared pain result and effectiveness between these two methods. Forty patients with primary trigger fingers were placed in a prospective randomized study to receive steroid injection with either the CI or P1I techniques. Demographic data were recorded. Immediately after the injection, pain score was recorded for each patient using the pain visual analog scale. The patients were followed every month for three months to determine recurrent symptoms. Student's t-test, chi-square and Fisher's exact test were used for data analysis. The mean pain VAS scores immediately post-injection were 7.3 ± 1.3 and 3.2 ± 2.2 in the CI and P1I techniques, respectively. The P1I technique group had a significantly lower pain score than CI technique group (p < 0.001). The recurrence rate was 15% in the CI technique when compared to 25% in the P1I technique which was not significant (p = 0.685). We concluded that the P1I technique is less painful than the CI technique without any significant difference in recurrence rate between the two groups at three months follow-up.

Areevijit W.,Chulalongkorn University | Kanongchaiyos P.,Chulalongkorn University
Proceedings of VRCAI 2011: ACM SIGGRAPH Conference on Virtual-Reality Continuum and its Applications to Industry | Year: 2011

In this paper, we present an algorithm for partial shape retrieval on a collection of 3D polygonal meshes. The proposed algorithm is invariant against rigid transformations and robust against non-rigid transformations. By using structure properties and geometric properties to represent shapes. Structure property is represented by a Reeb graph which uses an integral geodesic distance as a Morse function, whereas geometric property is represented by a Pose invariant Shape Signature. The main idea is to use Reeb graph for decomposing shape into many meaningful sub parts. Then describing each sub part by the Pose-invariant Shape Signature. The similarity is computed based on the Approximate Maximum Common Subgraph [Marini et al. 2005; Biasotti et al. 2006] for matching each sub-part between query shape and other while preserving topology. We evaluate our algorithm on various different model classes and deformation. © 2011 ACM.

Suvannasara P.,Chulalongkorn University | Siralertmukul K.,Chulalongkorn University | Muangsin N.,Chulalongkorn University
International Journal of Biological Macromolecules | Year: 2014

4-Carboxybenzensulfonamide-chitosan (4-CBS-chitosan) microspheres were prepared by electrospraying with acetazolamide (ACZ) as a model drug. The obtained 4-CBS-chitosan microspheres with or without ACZ-loading were characterized by Fourier transform infrared spectroscopy, differential scanning colorimetry, scanning electron microscopy and particle size analyses. The crystalline form and the stability of ACZ in a basic solution was determined using X-ray single crystal analysis. 4-CBS-chitosan had 90% encapsulation efficiency for ACZ compared to 47% of encapsulation efficiency (EE) obtained from native chitosan, forming 3.1. μm diameter microspheres with a low polydispersity index (0.4). After an initial burst release (58% in 5. min), ACZ-loaded 4-CBS-chitosan gave a sustained release of ACZ (~100% over 3. h) in simulated gastric fluid (0.1. N HCl; pH 1.2), which was better than that seen for the release from ACZ-loaded chitosan (44% over 1.5. h). Thus, 4-CBS-chitosan microspheres are a possible drug carrier in acidic conditions, such as at the gastric mucosal wall. © 2013 Elsevier B.V.

Keeratipibul S.,Chulalongkorn University | Phewpan A.,Chulalongkorn University | Lursinsap C.,Chulalongkorn University
LWT - Food Science and Technology | Year: 2011

The objectives of this study were to investigate the efficacy of two sanitizers, i.e. hypochlorous and peracetic acids, in reducing coliforms and Escherichia coli levels on tomato fruits and lettuce leaves, and to mathematically predict the relationship among the initial bacterial load, type of vegetable/fruit, types and concentration of sanitizer and residual microorganism levels after the sanitizing, by applying artificial neural networks (ANNs). The E. coli and coliforms used in this study were isolated from the two food types, and their cultures were activated in Tryptic Soy Broth (ca. 6-7log10 cfu/ml) before inoculating onto the fruit and vegetable. Both sanitizers reduced the number of the micro-organisms. However, as the hypochlorous acid concentration was increased, the level of viable coliforms and E. coli on the tomato fruits was reduced around 2-3log10 cfu/g (p ≤ 0.05), compared to only about 1log10 cfu/g reduction on lettuce leaves (p ≤ 0.05). Conversely, when the peracetic acid concentration was increased, the coliforms and E. coli levels on tomato fruits were reduced by some 3-4log10 cfu/g (p > 0.05) compared to only about 2log10 cfu/g on lettuce leaves (p > 0.05). The best sum square error from the neural prediction of residual coliforms and E. coli were 0.50 and 0.84, respectively, and the maximum R2 of residual coliforms and E. coli were 0.85 and 0.72, respectively. Only one hidden layer with three hidden neurons for coliforms and five for E. coli, were required to model this data. © 2010 Elsevier Ltd.

Plangklang P.,Chulalongkorn University | Reungsang A.,Chulalongkorn University | Reungsang A.,Khon Kaen University
Process Biochemistry | Year: 2010

The effectiveness of bioremediation technology in the removal of carbofuran from contaminated soil using a bioslurry phase sequencing batch reactor (SBR) was investigated. A 2-L laboratory glass bottle was used as a bioreactor with a working volume of 1.5 L at room temperature (27 ± 2 °C). One total cycle period of the SBR was comprised of 1 h of fill phase, 82 h of react phase, and 1 h of decant phase. The carbofuran concentration in the soil was 20 mg/kg soil. A carbofuran degrader isolated from carbofuran phytoremediated soil, namely Burkholderia cepacia PCL3 (PCL3) immobilized on corncob, was used as the inoculum. The results revealed that bioaugmentation treatment (addition of PCL3) gave the highest percentage of carbofuran removal (96.97%), followed by bioaugmentation together with biostimulation (addition of molasses) treatment (88.23%), suggesting that bioremediation was an effective technology for removing carbofuran in contaminated soil. Abiotic experiments, i.e. autoclaved soil slurry with corncob and no PCL3 treatment and autoclaved soil slurry with no PCL3 treatment, could adsorb 31.86% and 7.70% of carbofuran, respectively, which implied that soil and corncob could act as sorbents for the removal of carbofuran. © 2009 Elsevier Ltd. All rights reserved.

Sirichanchuen B.,Chulalongkorn University | Pengsuparp T.,Chulalongkorn University | Chanvorachote P.,Chulalongkorn University
Molecular and Cellular Biochemistry | Year: 2012

Cisplatin-based chemotherapy frequently resulted in acquired resistance of cancer cells. The underlying mechanism of such resistance is not fully understood especially the involvement of autophagy and autophagic cell death. This study thus investigated whether an alteration in autophagy could be responsible for cisplatin resistance in the long-term exposure lung carcinoma cells. The cisplatin resistant clone (H460/cis) of H460 cells was established by exposing the cells with gradually increasing concentrations of cisplatin until chemoresistance acquisition was elucidated by MTT, Hoechst 33342 staining and comet assays. Degree of autophagosome formation and level of LC3 marker were evaluated by acridine orange and western blot analysis, respectively. H460/cis cells exhibited irregular shape with ∼3-fold resistant to cisplatininduced apoptosis compared with H460 cells. Proteins analysis for LC3 indicated that the levels of LC3 in resistant cells were significantly lower than those in H460 cells. Moreover, autophagosome formation detected by acridine orange staining was dramatically reduced in the resistant cells, suggesting the role of autophagy in attenuating of cisplatin-induced cell death. Further, co-treatment of cisplatin with autophagy inducer, trifluorperazine, could resensitize H460/cis cells to cisplatin-induced cell death. Our findings reveal the novel mechanisms causing cisplatin resistance in lung carcinoma cells after long-term drug exposure regarding autophagy. © Springer Science+Business Media, LLC. 2011.

Keeratipibul S.,Chulalongkorn University | Techaruwichit P.,Chulalongkorn University
Food Control | Year: 2012

As a means to reduce the risk of Listeria spp. contamination in cooked frozen chicken meat process this study investigated the sources and the routes of infection using PCR-RAPD-based molecular typing. A total of 12,833 samples of final products (865), intermediate stage precut and packaged meat (4325) and environmental surfaces (7643) were screened for the presence of Listeria spp. Of the 401 positive isolates from the processing environment, the species were comprised of Listeria innocua (82.3%), Listeria welshimeri (11.2%), Listeria seeligeri (5.5%) and Listeria monocytogenes (1%). Twelve positive isolates of L. innocua and one each of L. welshimeri and L. seeligeri were found in the finished product. A total of 415 Listeria contaminated samples were further subjected to RAPD (randomly amplified polymorphic DNA) analysis to evaluate the relationship of the contaminants in the final product and those in the environment. L. innocua type LI 1.1, L. welshimeri type LW 1.5 and L. seeligeri type LS 1 were the only isolates found in the finished product, whilst L. innocua type LI 1.1 was persistently found in the surfaces of the food processing plant throughout the sampling period. The surfaces from which Listeria spp. were most frequently recovered were the liquid N 2 chiller exhaust pipe, the metal detector conveyor belt and the freezer drain. Therefore, the cleaning and sanitizing procedures were revised and strictly implemented to reduce and eliminate the real sources of Listeria contamination in the cooked frozen chicken meat process. © 2012 Elsevier Ltd.

Prombutara P.,Chulalongkorn University | Kulwatthanasal Y.,Chulalongkorn University | Supaka N.,National Science and Technology Development Agency | Sramala I.,National Science and Technology Development Agency | Chareonpornwattana S.,Chulalongkorn University
Food Control | Year: 2012

Nisin is a natural antimicrobial agent that is used as a preservative in heat processed and low pH foods. However, its bioactivity is lost by interaction with food components. Slow release nisin-loaded solid lipid nanoparticles (SLN) were produced by high pressure homogenization to provide protection from the food environment and prolong the biological activity. The optimized conditions for the preparation of Imwitor 900 based SLNs was a pressure of 1500 bars in a high pressure homogenizer for three cycles, with 5% (w/v) poloxamer 188 and 0.125% (w/v) sodium deoxycholate as the surfactant and co-surfactant, respectively. Unloaded SLN produced under this condition had the smallest nanometric particle size (119 ± 15.1 nm) with a narrow polydispersity (0.38 ± 0.03). Nisin-loaded SLNs, prepared from 0.5 to 3.0% (w/w) nisin, were larger than the unloaded SLN, with a size range of 159 ± 6.4-167 ± 8.6 nm, had a zeta-potential of -28.3 ± 0.15 to -29.2 ± 0.12 mV and nisin entrapment efficiency of 69.2 ± 0.04-73.6 ± 0.04%, the optimal being at 2% (w/w) nisin. During 28 day of aqueous suspension at 30 °C, the size of the SLNs increased to 214 ± 10.8-245 ± 15.7 nm and zeta-potential decreased to -21.6 ± 0.43 to -25.9 ± 0.34 mV. Scanning electron microscopy (SEM) demonstrated that nanoparticles had platelet shape. In vitro release studies revealed that nisin was released from the SLNs throughout the 25 day period but the release rate decreased as the pH of buffer increased from 2.0 to 7.4 and as the salt concentration increased, up to 0.5 M sodium chloride, whereupon high nisin was released within the first day. The antibacterial activity of nisin-loaded SLNs against Listeria monocytogenes DMST 2871 and Lactobacillus plantarum TISTR 850 was evident for up to 20 and 15 days, respectively, compared to only one and three days, respectively, for free nisin. © 2011 Elsevier Ltd.