Time filter

Source Type

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.

Somkotra T.,Chulalongkorn University
Geriatrics and Gerontology International | Year: 2013

Aim: To assess the socioeconomic-related inequality in dental care utilization among Thai elderly and to determine factors associated with the observed inequality after the country achieved universal coverage. Methods: The data were taken from the nationally representative Thailand Health & Welfare Survey 2007. Data of 10096 Thai elderly (aged over 60years) were selected. Descriptive analyses of the features of dental care utilization among Thai elderly were carried out, in addition to the concentration index (Cindex) being used to quantify the extent of socioeconomic-related inequality in dental care utilization. Logistic regression was used to determine factors associated with inequality in dental care. Results: Socioeconomic-related inequality in dental care utilization among Thai elderly was shown. Also, utilization was more concentrated among wealthier older adults, as shown by the positive value of Cindex (equals 0.244). The poor elderly, however, were more likely to utilize dental care at public facilities, particularly primary care facilities. Multivariate analysis showed that certain demographic, socioeconomic and geographic characteristics were particularly associated with poor-rich differences in dental care utilization among Thai elderly. Conclusions: Although socioeconomic-related inequality in dental care utilization among Thai elderly exists, the pro-poor utilization at public facilities, particularly primary care facilities, substantiates the concerted effort to reducing inequality in dental care utilization for Thai elderly. © 2012 Japan Geriatrics Society.

Purpose: To evaluate the effectiveness of subconjunctival anesthesia as compared to retrobulbar anesthesia for pain control during manual small-incision cataract surgery (MSICS) performed by third-year residents. Design: A randomized, controlled trial. Patients and methods: A total of 150 patients undergoing routine cataract surgery were randomly assigned to receive either subconjunctival anesthesia (group 1, n = 75) or retrobulbar anesthesia (group 2, n = 75). Third-year residents performed MSICS using the modified Blumenthal technique. Subconjunctival anesthesia was administered by injecting 2% xylocaine with adrenalin into the superior conjunctiva, and retrobulbar anesthesia by injecting 2 mL of 2% xylocaine with adrenalin into the retrobulbar space. We studied the following variables: intraoperative pain score rated on a 100-point visual analog scale (VAS), operative time, and injection and operative complications. Results: A mean age of 69 vs 70 years, an operative time of 47.1 (SD, 9.9) min vs 47.7 (10.9) min, and a median (interquartile range) pain score of 40 (range, 20-70) vs 40 (range, 20-50) were observed in the subconjunctival and the retrobulbar groups, respectively. The injection complication of subconjunctival hemorrhage was significantly higher in the subconjunctival group (25.3%) compared to the retrobulbar group (1.3%). The operative complication rate between groups was not different (P. 0.05). Conclusion: Both, superior subconjunctival anesthesia and retrobulbar anesthesia were effective during MSICS when used in a residency training program. © 2012 Kongsap, publisher and licensee Dove Medical Press Ltd.

Barnaud C.,CIRAD - Agricultural Research for Development | Le Page C.,CIRAD - Agricultural Research for Development | Dumrongrojwatthana P.,Chulalongkorn University | Trebuil G.,CIRAD - Agricultural Research for Development
Environmental Modelling and Software | Year: 2013

The objective of this paper is to question the increasingly common choice to build and use spatially explicit models, especially in the case of participatory agent-based modelling processes. The paper draws on a combination of lessons from literature and the case of a companion modelling process conducted in the context of a conflict about land and forest management in Northern Thailand. Using insights from negotiation theories, we analyze specifically the influence of spatial representations on the way people interacted, discussed and learnt from each other in the participatory modelling process. We argue that models that are spatially too explicit and realistic can actually impede the exploration of innovative and integrative scenarios in which ecological, social and economic objectives are mutually enriching. Indeed, spatial representations might lead to think in terms of boundaries and segregated space, and therefore prevent from thinking in terms of multifunctional space and from finding innovative and integrative solutions. © 2011 Elsevier Ltd.

Anderson G.,CRC | Maes M.,Chulalongkorn University
Current Pharmaceutical Design | Year: 2014

This paper reviews recent work on the biological underpinnings of clinical depression emphasizing the crucial role of immunoinflammatory and oxidative and nitrosative stress (O&NS) pathways in driving changes in neuronal regulating tryptophan catabolites (TRYCATs). The essence of the association of O&NS pathways with autoimmune responses in depression is via damage to lipid membranes, anchorage molecules and functional proteins that lead to changes in their chemical structures creating new modified epitopes (neoepitopes), which are highly immunogenic. The abovementioned pathways together with decreased antioxidant levels, including zinc, coenzyme Q10, glutathione and vitamin E, and melatonin are intimately involved in different aspects of depression, including mitochondrial functions and the regulation of cAMP/circadian genes, allowing for impacts across different aspects of symptom patterning. Immuno-inflammatory and O&NS processes may additionally cause alterations in blood-brain barrier permeability and neuroprogression, that is tissue damage, including neurodegeneration and apoptosis, and decreased neurogenesis and neuroplasticity. Activation of those interconnected pathways is relevant to the pathophysiology of acute and chronic depression and the progressive course (staging) of clinical depression. This implies that compounds that target these pathways may be useful to treat acute episodes and prevent further progression of the disease. We herein review some promising compounds, such as melatonin, melatonin receptor agonists, allopregnanolone, PDE4 inhibitors, statins, aspirin, sodium benzoate, tryptophan-enriched diets, and antioxidants, including epigallocatechin gallate, curcumin, quercitin, alpha-lipoic acid and resveratrol. © 2014 Bentham Science Publishers.

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.

Sangsuk S.,Chulalongkorn University
Materials Letters | Year: 2010

High surface area silver powder was prepared through Tollens process. The process involves reduction of Tollens reagent under sonication at room temperature. By gradually adding Tollens reagent into the mixture of glucose solution and sodium hydroxide solution, the silver powder forms immediately without silver mirror formation at container wall. The powders prepared through this process were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size distribution and surface area. The powders were cubic crystalline silver with bimodal distribution and primary particle size of < 1 μm and surface area of 1.8 m2/g. The yield of silver powder was higher than 99%. © 2010 Elsevier B.V. All rights reserved.

Shantavasinkul P.,World Health Organization | Wilde H.,Chulalongkorn University
Advances in Virus Research | Year: 2011

Human rabies is essentially a fatal disease once clinical signs develop. Rabies postexposure prophylaxis (PEP) consists of thorough wound care in combination with administration of rabies immunoglobulin and rabies vaccine. This is highly effective in rabies prevention if carried out diligently. Preexposure rabies prophylaxis simplifies PEP in the event of an exposure by eliminating the need for immunoglobulin. Shortened and more convenient and economical PEP regimens are being developed with promising results. They reduce the cost of PEP as well as travel expenses for the often very poor patients. The intradermal PEP regimen can now reduce the vaccine cost by ~. 60-70%. Although PEP in humans can prevent death, controlling the canine vector by sustained vaccination remains the mainstay of rabies elimination. © 2011 Elsevier Inc.

Wilde H.,Chulalongkorn University | Lumlertdacha B.,Red Cross
Advances in Virus Research | Year: 2011

Many cost-benefit/effective rabies research projects need to be carried out in less-developed canine-endemic regions. Among these are educational approaches directed at the public and governments. They would address effective primary wound care, availability, and proper use of vaccines and immunoglobulins, better reporting of rabies, final elimination of dangerous nerve tissue-derived vaccines, and the recognition that rabies is still expanding its geographic range. Such efforts could also reduce deaths in victims who had received no or less than adequate postexposure prophylaxis. There is a need for new technology in canine population control and sustainable vaccination. We have virtually no workable plans on how to control bat rabies, particularly that from hematophagous bats. Preexposure vaccination of villagers in vampire rabies-endemic regions may be one temporary solution. Current efforts to reduce further the time required and vaccine dose required for effective postexposure vaccination need to be encouraged. We still have incomplete understanding of the transport channels from inoculation site to rabies virus antibody generating cells. The minimum antigen dose required to achieve a consistently protective and lasting immune response has been established for intramuscular vaccine administration, but is only estimated for intradermal use. Greater knowledge may have clinical benefits, particularly in the application of intradermal reduced dose vaccination methods. Curing human rabies is still an unattained goal that challenges new innovative researchers. © 2011 Elsevier Inc.

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.

Laothamatas J.,Mahidol University | Sungkarat W.,Mahidol University | Hemachudha T.,Chulalongkorn University
Advances in Virus Research | Year: 2011

Rabies remains a virtually incurable disease once symptoms develop. Neuroimaging studies demonstrate lesions in the different parts of the neuroaxis, even before brain symptoms are evident. These abnormalities have been detailed in both rabies virus-infected humans and dogs with magnetic resonance imaging (MRI). MRI disturbances were similar in both forms (furious or paralytic) in human rabies; however, they were more pronounced in paralytic than in furious rabies virus-infected dogs in which examination was done early in the disease course. Abnormalities were not confined only to neuronal structures of hippocampus, hypothalamus, basal ganglia, and brain stem but also extended to white matter. The blood-brain barrier (BBB) has been clearly shown to be intact during the time rabies virus-infected patients and dogs remained conscious, whereas leakage was demonstrated as soon as they became comatose. Although the location of MRI abnormalities can help diagnosing rabies, the intensities of signals are usually not very distinct and sometimes not recognizable. Newer techniques and protocols have been developed and utilized, such as diffusion-weighted imaging and diffusion tensor imaging, and the latter provides both qualitative and quantitative data. These techniques have been applied to normal and rabies virus-infected dogs to construct fractional anisotropy and mean diffusivity maps. Results showed clear-cut evidence of BBB intactness with absence of vasogenic brain edema and preservation of most neuronal structures and tracts except at the level of brainstem in paralytic rabies-infected dogs. Neuroimaging is one of the most useful tools for the in vivo study of central nervous system infections. © 2011 Elsevier Inc.

Krisdapong S.,Chulalongkorn University | Sheiham A.,University College London | Tsakos G.,University College London
Quality of Life Research | Year: 2012

Purpose To assess the prevalence and characteristics of oral impacts attributed to recurrent aphthous stomatitis (RAS) in 12- and 15-year-olds Thais. Methods A national oral health survey was conducted. Child-OIDP and OIDP indices were used to collect oral impacts in 1,100 12- and 871 15 year olds. Results RAS-related impacts were reported in 24.7% of 12 and 36.2% of 15 year olds. Girls were more likely than boys to report RAS-related impacts. Among all perceived causes of oral impacts, RAS ranked second for 12 and first for 15 year olds. Among 12 and 15 years olds, 79.8 and 86.8% respectively had impacts on eating, 81.0 and 84.4% on cleaning teeth and 51.7 and 60.3% on emotional stability. For individual children, impacts affected between 1-6 daily performances. Impacts were of 'little' and 'moderate' intensity for 12 and 15 year olds, respectively. RAS-related impacts occurred mostly in combination with impacts from other oral conditions. Combined with other oral conditions, the impacts were worse, in terms of score, intensity and extent, than when RAS occurred alone. Conclusions RAS-related impacts were common in 12- and 15-year-old Thai children and mostly affected eating, cleaning teeth and emotional stability. RAS tended to occur with other conditions leading to more severe, more extensive impacts on quality of life. © Springer Science+Business Media B.V. 2011.

Panedpojaman P.,Prince of Songkla University | Thepchatri T.,Chulalongkorn University
International Journal of Steel Structures | Year: 2013

The effect of the cellular beam configuration on the deflection has been investigated by using the three-dimensional finite element analysis of 408 cellular beams. Cross-section dimension, beam slenderness, opening size and opening spacing are found to affect the stiffness of the analytical load-deflection curve. The parametric study of the FE stiffness and normalized stiffness is conducted. The stress distribution of the finite element (FE) model reveals the strut stress in the web-post contributes to the increasing deflection in addition to the regular bending deflection. The deformation of the web-post and the relative movement between the upper and lower tee-sections due to strut stress is the main reason of the additional deflection in the cellular beams. The effect of the strut stress is found to be significant for the deflection of the short-span beams but less for the long-span beams. To convert the theoretical bending deflection to be the overall deflection, the calibrating coefficient function is established by using the empirical study. The function is formulated in terms of the slenderness, spacing and cross section ratio. The deflection prediction is useful to check serviceability condition for the design purpose. © 2013 Korean Society of Steel Construction and Springer-Verlag Berlin Heidelberg.

Bunyavejchevin S.,Chulalongkorn University
Journal of Obstetrics and Gynaecology Research | Year: 2015

Aims To evaluate voiding symptoms and questionnaire score change before and after anti-muscarinic treatment and evaluate the correlation of agreement in patient and doctor satisfaction after treatment. Methods Forty women newly diagnosed with overactive bladder (OAB), attending the urogynecology clinic at Chulalongkorn Hospital during April-June 2011 were recruited. Tolterodine 4 mg orally once daily was given for 4 weeks. A voiding diary and Thai version of the OAB questionnaires eight-item Overactive Bladder awareness tool (OAB-v8), Overactive Bladder Symptoms Score (OABSS) and Overactive Bladder QOL (OABq) were completed before and at the end of treatment. At the end of the trial, self-report patient satisfaction, and doctor satisfaction (according to symptom improvement in the voiding diary) were assessed. Student's t-test and weighted kappa coefficients were used in statistical analysis. Sample size was calculated from an OAB questionnaire pilot study with 20% addition for loss to follow up. Results All voiding parameters and questionnaire scores (OAB-v8, OABSS and OABq) were improved after treatment. Weighted kappa was only 0.06, between doctor and patient satisfaction. Conclusion OAB-v8 and OABSS questionnaires can be used as screening and follow-up tools. There is poor agreement between patient and doctor satisfaction. Satisfaction should therefore be measured from the patient's perspective. © 2015 The Author. Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology.

Nutescu E.,University of Illinois at Chicago | Nutescu E.,University of Chicago | Chuatrisorn I.,Chulalongkorn University | Hellenbart E.,University of Chicago | Hellenbart E.,University of Illinois at Chicago
Journal of Thrombosis and Thrombolysis | Year: 2011

Clinicians and patients around the world have been intrigued by the concept of developing an oral anticoagulant with a broad therapeutic window and few drug and dietary interactions that can be administered at fixed doses with no or minimal monitoring. The recently approved oral direct thrombin inhibitor dabigatran, along with the emerging oral anti-factor Xa inhibitors, rivaroxaban, apixaban, and edoxaban, have been developed to address many of the shortcomings of warfarin therapy. As warfarin is associated with extensive food and drug interactions, there is also a need to consider such interactions with the new oral anticoagulants. While to date few drug and dietary interactions have been reported with the new oral anticoagulants, it is still early in their development and clinical use cycle. Pharmacokinetic and pharmacodynamic profiles will have to be closely accounted for when determining the likelihood of a potential drug interaction prior to therapy initiation. As the list of drugs and supplements that interact with warfarin is continuously expanding, and the knowledge on drug interactions with the novel oral anticoagulants is still in its infancy, clinicians need to be vigilant when initiating any of these agents or when any changes in the patient's medication profile occur and perform a close screening for potential drug and dietary interactions. The objective of this paper is to give an update on drug and dietary interactions with warfarin and the novel oral anticoagulants, dabigatran, rivaroxaban, apixaban, and edoxaban. © Springer Science+Business Media, LLC 2011.

Sasat S.,Chulalongkorn University | Bowers B.J.,University of Wisconsin - Madison
Gerontologist | Year: 2013

Thailand is a Buddhist country located on the mainland of southeast Asia, where 3-generation homes are still common. Care of older adults is primarily a family responsibility. Recent policy changes mean that all Thais are now eligible for services through the national health care system. Almost half the population has no retirement pension, leaving responsibility for support of older adults largely to extended family. Long-term care is becoming a serious concern as the population ages, women move into the workforce, and family size decreases. Thai researchers have focused on issues related to health and nutrition, income security, housing, general population aging, local and community care and services, information and education, and quality of life. There is currently no formal long-term care system. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved.

Kidyoo M.,Chulalongkorn University
Nordic Journal of Botany | Year: 2015

Ceropegia cochleata Kidyoo, described a new below, is known from three populations in northern and northeastern Thailand. Comprehensive description, illustrations, photographs, and comparisons with the morphologically similar C. beddomei Hook. f., are here provided. Ceropegia cochleata is distinguished by its conspicuously hairy inner surface of the swollen basal part of the corolla tube and by the shape of inner coronal lobes. Nordic Journal of Botany © 2015 Nordic Society Oikos.

Liamputtong P.,La Trobe University | Haritavorn N.,Thammasat University | Kiatying-Angsulee N.,Chulalongkorn University
Qualitative Health Research | Year: 2012

Living with an incurable illness such as HIV/AIDS is a stressful experience. However, many HIV-positive individuals are able to maintain their emotional well-being. This begs the question of what strategies these individuals employ to allow them to do so. In this article, we examine how Thai women living with HIV/AIDS learned about their health status, what feelings they had, and how they dealt with the illness. In-depth interviews were conducted with 26 women in central Thailand. The women adopted several strategies to deal with their HIV status, including taking care of themselves, accepting their own faith, disclosing their HIV status to family, and joining AIDS support groups. These strategies can be situated within the "living positively" discourse, which helped to create a sense of optimism to combat the HIV epidemic among the women. Additionally, the acceptance of their HIV status played an essential role in the meaning-making process because it assisted the women in sustaining the equilibrium of their emotional well-being. © 2012 SAGE Publications.

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.

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.

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.

Hermann L.K.,Mount Sinai School of Medicine | Newman D.H.,Mount Sinai School of Medicine | Pleasant W.A.,Mount Sinai School of Medicine | Rojanasarntikul D.,Mount Sinai School of Medicine | And 5 more authors.
JAMA Internal Medicine | Year: 2013

Importance: The American Heart Association recommends routine provocative cardiac testing in accelerated diagnostic protocols for coronary ischemia. The diagnostic and therapeutic yield of this approach are unknown. Objective: To assess the yield of routine provocative cardiac testing in an emergency department-based chest pain unit. Design and Setting: We examined a prospectively collected database of patients evaluated for possible acute coronary syndrome between March 4, 2004, and May 15, 2010, in the emergency department-based chest pain unit of an urban academic tertiary care center. Participants: Patients with signs or symptoms of possible acute coronary syndrome and without an ischemic electrocardiography result or a positive biomarker were enrolled in the database. Exposures: All patients were evaluated by exercise stress testing or myocardial perfusion imaging. Main Outcomes and Measures: Demographic and clinical features, results of routine provocative cardiac testing and angiography, and therapeutic interventions were recorded. Diagnostic yield (true-positive rate) was calculated, and the potential therapeutic yield of invasive therapy was assessed through blinded, structured medical record review using American Heart Association designations (class I, IIa, IIb, or lower) for the potential benefit from percutaneous intervention. Results: In total, 4181 patients were enrolled in the study. Chest pain was initially reported in 93.5%,most (73.2%) were at intermediate risk for coronary artery disease, and 37.6% were male. Routine provocative cardiac testing was positive for coronary ischemia in 470 (11.2%), of whom 123 underwent coronary angiography. Obstructive disease was confirmed in 63 of 123 (51.2% true positive), and 28 (0.7% overall) had findings consistent with the potential benefit from revascularization (American Heart Association class I or IIa). Conclusions and Relevance: In an emergency department-based chest pain unit, routine provocative cardiac testing generated a small therapeutic yield, new diagnoses of coronary artery disease were uncommon, and false-positive results were common. ©2013 American Medical Association. 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.

Tangaramvong S.,University of New South Wales | Tin-Loi F.,University of New South Wales | Senjuntichai T.,Chulalongkorn University
International Journal of Solids and Structures | Year: 2011

This paper presents a numerical method to identify and trace the critical post-collapse response of rigid perfectly-plastic structures. To account for the possibility of multiple equilibrium paths, the critical one is directly identified using the minimum 2nd-order work criterion. Our proposed enhanced sequential limit analysis is formulated as an instance of the challenging class of optimization problems known as a mathematical program with equilibrium constraints (MPEC). This MPEC formulation minimizes the 2nd-order work expression subject to the set of constraints describing the complete complementarity system (in mixed static-kinematic variables) governing simultaneously the two adjacent equilibrium configurations, namely the current one and its neighboring state. We use a nonlinear programming based algorithm, involving relaxation of the complementarity terms, to solve the MPEC. Four numerical examples are provided to illustrate application of the proposed scheme. © 2011 Elsevier Ltd. All rights reserved.

Assavalapsakul W.,Chulalongkorn University
Genetics and molecular research : GMR | Year: 2012

The black tiger shrimp (Penaeus monodon) is economically important in many parts of the world, including Thailand. Shrimp immunity is similar to that of other invertebrate organisms; it consists of an innate immunity system. Toll or Toll-like receptors (TLRs) play an essential role in recognizing the cleaved form of the cytokine Spätzle, which is processed by a series of proteolytic cascades activated by secreted recognition molecules. We isolated a full-length Toll receptor from P. monodon. The cloned full-length sequence of the PmToll cDNA consists of 4144 nucleotides, containing a 5'-UTR with 366 nucleotides, a 3'-terminal UTR with 985 nucleotides, with a classical polyadenylation signal sequence AATAAA, a poly A-tail with 27 nucleotides, and an open reading frame coding for 931 amino acids. The deduced amino acid sequence of PmToll is a typical type I membrane domain protein, characteristic of TLR functional domains. It includes a putative signal peptide, an extracellular domain consisting of leucine-rich repeats, flanked by cysteine-rich motifs, a single-pass transmembrane portion, and a cytoplasmic TLR domain. PmToll was expressed in all tissues tested, including gill, hemocytes, heart, hepatopancreas, lymphoid organs, muscle, nerve, pleopod, stomach, testis, and ovary. The deduced amino acid of PmToll is closely related to that of other shrimp Tolls, especially FcToll. Further studies elucidating the mechanism of action of Tolls will be of benefit for understanding the defense mechanisms of this economically important aquatic species.

Chairuangkitti P.,Chulalongkorn University
Toxicology in vitro : an international journal published in association with BIBRA | Year: 2013

Silver nanoparticles (AgNPs) are incorporated into a large number of consumer and medical products. Several experiments have demonstrated that AgNPs can be toxic to the vital organs of humans and especially to the lung. The present study evaluated the in vitro mechanisms of AgNP (<100 nm) toxicity in relationship to the generation of reactive oxygen species (ROS) in A549 cells. AgNPs caused ROS formation in the cells, a reduction in their cell viability and mitochondrial membrane potential (MMP), an increase in the proportion of cells in the sub-G1 (apoptosis) population, S phase arrest and down-regulation of the cell cycle associated proliferating cell nuclear antigen (PCNA) protein, in a concentration- and time-dependent manner. Pretreatment of the A549 cells with N-acetyl-cysteine (NAC), an antioxidant, decreased the effects of AgNPs on the reduced cell viability, change in the MMP and proportion of cells in the sub-G1population, but had no effect on the AgNP-mediated S phase arrest or down-regulation of PCNA. These observations allow us to propose that the in vitro toxic effects of AgNPs on A549 cells are mediated via both ROS-dependent (cytotoxicity) and ROS-independent (cell cycle arrest) pathways. Copyright © 2012 Elsevier Ltd. All rights reserved.

Tongsopit S.,Chulalongkorn University
Energy for Sustainable Development | Year: 2015

This paper reviews Thailand's feed-in tariff framework for the support of solar power production and provides a feasibility analysis of residential-scale rooftop solar PV investment in Thailand under three scenarios. The initial phase of feed-in tariff support for solar power in the form of "Adder" gave rise to the dominance of solar farms, contributing currently to 99% of Thailand's solar power capacity. Since 2013, the government has begun to give a more focused support to rooftop solar power investment in the form of fixed feed-in tariff. However, the response to the government's feed-in tariff support for residential rooftop solar has been slow. Among many reasons, this paper argues that the lack of feasibility of residential rooftop solar power investment remains a key barrier. Under current market conditions, such investment could potentially be stimulated with the presence of a tax incentive and more attractive financing options. © 2015 International Energy Initiative.

Burnett K.,University of Hawaii at Manoa | Pongkijvorasin S.,Chulalongkorn University | Roumasset J.,University of Hawaii at Manoa
Environmental and Resource Economics | Year: 2012

This paper develops a two-stage model for the optimal management of a potential invasive species. The arrival of an invasive species is modeled as an irreversible event with an uncertain arrival time. The model is solved in two stages, beginning with the post-invasion stage. Once the arrival occurs, the optimal path of species removal is that which minimizes the present value of damage and removal costs plus the expected present value of prevention costs. An expenditure-dependent, conditional hazard rate describing species arrival is developed based on discussions with natural resource managers. We solve for the optimal sequence of prevention expenditures, given the minimum invasion penalty as just described. For the case of the Brown Tree Snake potentially invading Hawaii, we find that pre-invasion expenditures on prevention are inverse U-shaped in the hazard rate. Efficient prevention should be approximately $2. 9 million today and held constant until invasion. Once invasion occurs, optimal prevention requires $3. 1 million annually and $1. 6 million per year on species removal to keep the population at its steady state level, due to high search costs at very small population levels. © 2011 Springer Science+Business Media B.V.

Tangjitsitcharoen S.,Chulalongkorn University
Advanced Materials Research | Year: 2011

The objective of this research is to propose a practical model to predict the in-process surface roughness during the turning process by using the cutting force ratio. The proposed in-process surface roughness model is developed based on the experimentally obtain result by employing the exponential function with six factors of the cutting speed, the feed rate, the rank angle the tool nose radius, the depth of cut, and the cutting force ratio. The multiple regression analysis is utilized to calculate the regression coefficients with the use of the least square method. The prediction accuracy of the in-process surface roughness model has been verified to monitor the in-process predicted surface roughness at 95% confident level. All those parameters have their own characteristics to the arithmetic surface roughness and the surface roughness. It has been proved by the cutting tests that the proposed and developed in-process surface roughness model can be used to predict the in-process surface roughness by utilizing the cutting force ratio with the highly acceptable prediction accuracy. © (2011) Trans Tech Publications.

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.

Gumert M.D.,Nanyang Technological University | Malaivijitnond S.,Chulalongkorn University
American Journal of Physical Anthropology | Year: 2012

Long-tailed macaques (Macaca fascicularis) feed opportunistically in many habitats. The Burmese subspecies (M. f. aurea) inhabits coastal areas in southwestern Thailand and Myanmar, and some of their populations have adapted lithic customs for processing encased foods in intertidal habitats. We investigated the diet of such macaques in Laemson National Park, Thailand, and identified the variety of foods they processed with stones. We conducted 36 shore surveys to study tool sites following feeding activity, during which we counted the minimum number of individual (MNI) food items found at each site. We identified 47 food species (43 animals and four plants), from 37 genera. We counted 1,991 food items during surveys. Nearly all were mollusks (n = 1,924), with the small remainder primarily consisting of crustaceans and nuts. The two most common foods, rock oysters (Saccostrea cucullata; n = 1,062) and nerite snails (Nerita spp.; n = 538), composed 80.2% of our sample. Four prey species comprised 83.2% of the sample (MNI = 1,656), S. cucullata (n = 1,062), Nerita chamaeleon (n = 419), Thais bitubercularis (n = 95), and Monodonta labio (n = 80). Macaques selected a wide variety of foods. However, they heavily concentrated on those that were abundant, easy to access, and sufficiently sized. The Burmese long-tailed macaque stone-processed diet, which focuses on intertidal marine prey, differs from Sapajus and Pan, who use stones primarily for encased nuts and fruits. In terms of diversity of foods exploited, coastal stone-based predation by macaques resembles the diet of coastal-foraging humans (Homo sapiens sapiens). Copyright © 2012 Wiley Periodicals, Inc.

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.,.

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.

Chuchawankul S.,Chulalongkorn University
Genetics and molecular research : GMR | Year: 2012

Piperine, an amide isolated from Piper species (Piperaceae), has been reported to exhibit central nervous system depression, anti-pyretic and anti-inflammatory activity. Immunomodulatory and anti-tumor activity of piperine has been demonstrated in mouse carcinomas. However, there is little information available concerning the effect of piperine on humans. We evaluated the immunopharmacological activity of this compound in human immune cells. Human peripheral blood mononuclear cells (PBMCs) were exposed to piperine, and cell proliferation was determined by the MTS assay. Piperine significantly inhibited phytohemagglutinin-stimulated human PBMC proliferation after exposure for 72 h. This compound inhibited PBMC activity, with an IC(50) of 100.73 ± 11.16 μg/mL. Production of interleukin-2 (IL-2) and interferon-γ (IFN-γ) was measured using an ELISA assay and RT-PCR. Piperine inhibited IL-2 and IFN-γ production in the PBMCs. RT-PCR data indicated that IL-2 and IFN-γ mRNA expression in PBMCs is suppressed by piperine. This compound significantly inhibited the production of these two cytokines by activated PBMCs in a dose-dependent manner. In conclusion, piperine appears to have potential as an immunomodulatory agent for immune system suppression.

Kuvatanasuchati J.,Chulalongkorn University
Tropical biomedicine | Year: 2012

This work was to assess the isolation and identification of Thai oral bacteria. Seventeen viridans group streptococci (VGS) and seventeen lactic acid bacteria from saliva were characterization based on their morphological, physiological and biochemical characteristics and the 16S RNA gene sequences analysis. The Gram-positive cocci in chains of viridans group comprised of six isolates (Group I) were identified as Streptococcus gordonii, 6 isolates (Group II) were Streptococcus salivarius, 4 isolates (Group III) were Streptococcus sanguis and one isolate (Group IV) was Streptococcus mutans. Seventeen lactic acid bacterial isolates were Gram-positive and catalase negative. They did not contained diaminopimelic acid in the cell wall peptidoglycan. They were divided into four groups, the rod-shaped in Group A (11 isolates) and Group B (2 isolates) which were identified as Lactobacillus fermentum and Lactobacillus salivarius, respectively. The tetrad-forming cocci in Group C (3 isolates) and Group D (1 isolate) were identified as Pediococcus acidilactici and P. pentosaceus, respectively.

Trichaiyapon V.,Chulalongkorn University
Journal of investigative and clinical dentistry | Year: 2012

To investigate the cytotoxicity of three flowable resin composites that potentially useful as retrograde filling materials, compared with mineral trioxide aggregate (MTA). Ten standard cylinder discs were used for each of the tested materials: Tetric Flow, Filtex Flow, Aeliteflo, and MTA, which were prepared under aseptic conditions. Cytotoxicity of eluates from all materials after 1-4 days' immersion in culture medium and direct contact cytotoxicity were evaluated using cultured human periodontal ligament cells (PDLC). The colorimetric (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and scanning electron microscope of cell morphology (direct contact only) were used. No eluates of set materials demonstrated cytotoxicity at any concentration or elution time. Freshly-mixed MTA was cytotoxic in direct contact, but not set MTA. Freshly-mixed Aeliteflo was also cytotoxic, as was set material up to 2 days' elution. With morphological assessment, some differences were seen among resin composites, but all changes were rated as slight using the International Standard Organization criteria. Of all of the materials tested, Tetric Flow showed the least cytotoxic effects on PDLC. Further research is needed to determine the clinical usefulness of flowable composites as retrograde filling materials. © 2012 Blackwell Publishing Asia Pty Ltd.

Petchwattana N.,Srinakharinwirot University | Covavisaruch S.,Chulalongkorn University
Materials and Design | Year: 2011

This research aims to investigate the effects of chemical blowing agent (CBA) contents and particle sizes on the properties of foamed poly(vinyl chloride) (PVC)/rice hull (RH) composites. Fine particles of azodicarbonamide (AC) at 5, 8, 11 and 22 μm were modified with 20% by weight of ZnO and used at 0-3.0% by weight. The average cell size and density of the PVC/RH foamed profiles were reduced as the content of modified azodicarbonamide (mAC) increased. Larger mAC particles lowered the density more effectively. Maximum reduction of density by 46% was achieved when mAC 22 μm was applied at 2.0% by weight. Larger blowing particles led to PVC/RH foam with greater flexural modulus and strength. Greater impact strength, observed when 5 μm mAC was applied, resulted from the rather thick cell wall created abundantly when fine mAC was applied. © 2011 Elsevier Ltd.

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.

Ananthanawat C.,Chulalongkorn University | Vilaivan T.,Organic Synthesis Research Unit | Hoven V.P.,Organic Synthesis Research Unit | Su X.,Institute of Materials Research and Engineering of Singapore
Biosensors and Bioelectronics | Year: 2010

Pyrrolidinyl peptide nucleic acid bearing a d-prolyl-2-aminocyclopentanecarboxylic acid backbone (acpcPNA) has been evaluated as a new sensing probe for detection of DNA hybridization. In this study, the biotinylated acpcPNA was immobilized on surface plasmon resonance (SPR) sensor chips via biotin-streptavidin interactions for solid-phase DNA hybridization. A critical comparison between acpcPNA, DNA and conventional peptide nucleic acid (aegPNA) probes of the same sequence was made by means of SPR on various important aspects. These include the effect of ionic strength on hybridization efficiency, the specificity to detect the mismatch(es) in target DNAs, the direction of binding (parallel or antiparallel) to target DNAs, and the effect of target DNA concentration on hybridization efficiency. Results indicated that the immobilized acpcPNA probe possesses distinct hybridization properties relative to aegPNA (and/or DNA) counterparts, including a higher single-base mismatch sensitivity, antiparallel selectivity and low ionic strength dependence of target hybridization. These properties substantiate the acpcPNA applicability as sensor probes for clinical and diagnostic applications. With a proper selection of regeneration conditions (10 mM NaOH, 2 min exposure), the sensor can be reused for multiple cycles of hybridization with as little as 1.3% loss in hybridization activity per regeneration cycle. © 2009 Elsevier B.V. All rights reserved.

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.

Sarachana T.,George Washington University | Sarachana T.,Chulalongkorn University | Hu V.W.,George Washington University
Molecular Autism | Year: 2013

Background: Our independent cohort studies have consistently shown the reduction of the nuclear receptor RORA (retinoic acid-related orphan receptor-alpha) in lymphoblasts as well as in brain tissues from individuals with autism spectrum disorder (ASD). Moreover, we have found that RORA regulates the gene for aromatase, which converts androgen to estrogen, and that male and female hormones regulate RORA in opposite directions, with androgen suppressing RORA, suggesting that the sexually dimorphic regulation of RORA may contribute to the male bias in ASD. However, the molecular mechanisms through which androgen and estrogen differentially regulate RORA are still unknown. Methods. Here we use functional knockdown of hormone receptors and coregulators with small interfering RNA (siRNA) to investigate their involvement in sex hormone regulation of RORA in human neuronal cells. Luciferase assays using a vector containing various RORA promoter constructs were first performed to identify the promoter regions required for inverse regulation of RORA by male and female hormones. Sequential chromatin immunoprecipitation methods followed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) analyses of RORA expression in hormone-treated SH-SY5Y cells were then utilized to identify coregulators that associate with hormone receptors on the RORA promoter. siRNA-mediated knockdown of interacting coregulators was performed followed by qRT-PCR analyses to confirm the functional requirement of each coregulator in hormone-regulated RORA expression. Results: Our studies demonstrate the direct involvement of androgen receptor (AR) and estrogen receptor (ER) in the regulation of RORA by male and female hormones, respectively, and that the promoter region between -10055 bp and -2344 bp from the transcription start site of RORA is required for the inverse hormonal regulation. We further show that AR interacts with SUMO1, a reported suppressor of AR transcriptional activity, whereas ER interacts with the coactivator NCOA5 on the RORA promoter. siRNA-mediated knockdown of SUMO1 and NCOA5 attenuate the sex hormone effects on RORA expression. Conclusions: AR and SUMO1 are involved in the suppression RORA expression by androgen, while ER and NCOA5 collaborate in the up-regulation of RORA by estrogen. While this study offers a better understanding of molecular mechanisms involved in sex hormone regulation of RORA, it also reveals another layer of complexity with regard to gene regulation in ASD. Inasmuch as coregulators are capable of interacting with a multitude of transcription factors, aberrant expression of coregulator proteins, as we have seen previously in lymphoblasts from individuals with ASD, may contribute to the polygenic nature of gene dysregulation in ASD. © 2013 Sarachana and Hu; licensee BioMed Central Ltd.

Poonsuk K.,Chulalongkorn University
The Southeast Asian journal of tropical medicine and public health | Year: 2012

Resistance to various antimicrobial agents is an increasing problem in Pseudomonas aeruginosa and Acinetobacter baumannii infections. In this study, the roles of integrons were examined in 101 P. aeruginosa isolates and 176 A. baumannii isolates from patients. The frequencies and characteristics of class 1, 2 and 3 integrons were investigated and the horizontal transfer of integrons was assessed. Among these isolates, class 1 integrons with a resistance gene cassette were detected in 69.3% of P. aeruginosa and 31.8% of A. baumannii isolates, but class 2 and 3 integrons were not found. Five novel gene cassette arrays were identified in P. aeruginosa: aacA7-cmlA, aadB-blaOXA,-o-aadA1, aadB-arr-2-cmlA-blaOXA,-o-aadA1, aadB-cmlA-aadA1 and aadB-cmlA-blaOXA-10-aadA15. The integrons found in A. baumannii isolates in this study were previously reported. Horizontal transfer of some class 1 integrons was detected in both P. aeruginosa (2/70) and A. baumannii (5/57). These data confirm the high prevalence of class 1 integrons with a variety of gene cassette combinations among multidrug-resistant P. aeruginosa and A. baumannii clinical isolates.

Talchai C.,Columbia University | Talchai C.,Chulalongkorn University | Xuan S.,Columbia University | Lin H.V.,Lilly China Research and Development Center | And 2 more authors.
Cell | Year: 2012

Diabetes is associated with β cell failure. But it remains unclear whether the latter results from reduced β cell number or function. FoxO1 integrates β cell proliferation with adaptive β cell function. We interrogated the contribution of these two processes to β cell dysfunction, using mice lacking FoxO1 in β cells. FoxO1 ablation caused hyperglycemia with reduced β cell mass following physiologic stress, such as multiparity and aging. Surprisingly, lineage-tracing experiments demonstrated that loss of β cell mass was due to β cell dedifferentiation, not death. Dedifferentiated β cells reverted to progenitor-like cells expressing Neurogenin3, Oct4, Nanog, and L-Myc. A subset of FoxO1-deficient β cells adopted the α cell fate, resulting in hyperglucagonemia. Strikingly, we identify the same sequence of events as a feature of different models of murine diabetes. We propose that dedifferentiation trumps endocrine cell death in the natural history of β cell failure and suggest that treatment of β cell dysfunction should restore differentiation, rather than promoting β cell replication. PaperFlick: © 2012 Elsevier Inc.

Lertkhachonsuk R.,Chulalongkorn University
Journal of the Medical Association of Thailand | Year: 2015

Objective: To study the correlation between serum and urine hCG levels in gestational trophoblastic disease (GTD) patients with low hCG level. The correlation between serum hCG and results from urine pregnancy tests are evaluated along with quantitative measurement. Material and Method: In this prospective study, 86 cases of gestational trophoblastic disease patients with positive and low level of serum hCG (<100 mIU/ml) were recruited. Quantitative serum hCG, urine hCG and urine pregnancy test were performed. The correlation coefficients between serum and urine hCG were then analyzed by SPSS 16.0. Furthermore, the levels of serum hCG were compared to the results of the urine pregnancy test. Results: From February 2006 to June 2008, 86 cases were recruited for this study. The correlation coefficient between serum and urine hCG levels in all cases was 0.44 (using Pearson correlation), p = 0.01. In subgroup analysis, the correlation coefficient between serum and urine hCG levels in chemosensitive gestational trophoblastic neoplasia (GTN) patients (n = 27) was 0.73, p≤0.01. The correlation coefficient in chemoresistant GTN patients (n = 38) was 0.29, p = 0.07; and the correlation coefficient in hydatidiform mole patients (n = 21) was 0.47, p = 0.03. A urine pregnancy test was positive only in 10 of 86 specimens. Conclusion: The correlation coefficient between serum and urine hCG in GTD patients with low hCG level showed significant correlation. However, patients with chemoresistance had less correlation than those with chemosensitivity and hydatidiform mole. Urine pregnancy test had low correlation with urine hCG and was not useful in this group of patients. © 2015, Medical Association of Thailand. All rights reserved.

Tangjitsitcharoen S.,Chulalongkorn University
Key Engineering Materials | Year: 2010

In order to realize an intelligent machine tool, an in-process monitoring system is developed to estimate the in-process surface roughness. The objective of this research is to propose a method to estimate the surface roughness during the in-process cutting by utilizing the in-process monitoring of cutting forces. The proposed in-process surface roughness model is developed based on the experimentally obtained results by employing the exponential function with five factors of the cutting speed, the feed rate, the tool nose radius, the depth of cut, and the cutting force ratio. The multiple regression analysis is utilized to calculate the regression coefficients with the use of the least square method. The prediction interval of the in-process surface roughness model has been also presented to monitor and control the in-process estimated surface roughness at 95% confident level. It is proved by the cutting tests that the proposed and developed in-process surface roughness model can be effectively used to monitor and estimate the in-process surface roughness by utilizing the cutting force ratio with the highly acceptable prediction accuracy achieved. © (2010) Trans Tech Publications, Switzerland.

Petchwattana N.,Srinakharinwirot University | Covavisaruch S.,Chulalongkorn University
Journal of Bionic Engineering | Year: 2014

The present research aims to utilize the acrylic Core-Shell Rubber (CSR) particles to reduce the brittleness in Wood Plastic Composites (WPC) prepared from poly(lactic acid) (PLA) and rubber wood sawdust (Hevea brasiliensis). Experimental works consisted of two major parts. The first part concentrated on toughening PLA by using CSR particles. Mechanical tests revealed that PLA had become tougher with a more than five times increment in the impact strength when the CSR was added at only 5 wt%. The modified PLA was less stiff with the significant reductions of both elastic and flexural moduli and strengths. The second part focused on producing WPC from the toughened PLA and rubber wood sawdust. The tensile moduli and the strengths of the PLA composites increased with rubber wood content. The composites turned out to be more brittle with reductions of both the impact strength and the tensile elongation at break at all the sawdust contents. Toughening PLA/wood flour with 5 wt% CSR improved both the impact strength and the tensile elongation at break. The toughness enhancement was also depicted by the plastic deformation observed on the surfaces of fractured PLA/CSR/wood sawdust composites. © 2014 Jilin University.

Tummaruk P.,Chulalongkorn University | Sang-Gassanee K.,Intervet Thailand Ltd
Tropical Animal Health and Production | Year: 2013

The aim of the present study was to investigate the effects of farrowing duration, parity number, and type of anti-inflammatory drug used postpartum on the incidence of postparturient disorders in sows. The duration of farrowing and postparturient disorders were examined in 64 sows at Days 0, 1, 2, and 3 after farrowing. The sows were classified according to parity number (1, 2-4, and 5-7), duration of farrowing (<2, 2-2. 9, 3-3. 9, and 4-8 h), and the type of anti-inflammatory drugs (flunixin méglumine and dipyrone). The farrowing duration was 178. 0 ± 73. 5 min (2. 96 h). The percentage of sows with fever increased from 40 to 100 % when the farrowing duration increased from <2 to 4-8 h. On Day 1 of the postpartum, 93. 7 % of primiparous sows had fever, while 52. 6 and 47. 6 % of sows parity 2-4 and 5-7 had a fever (P < 0. 05). The presence of vaginal discharge on Day 1 of the postpartum was higher in sows of parity 5-7 than sows of parity 2-4 (85. 7 and 52. 6 %, P = 0. 029). The use of flunixin méglumine after parturition in sows reduced the percentage of sows with a fever from 61. 3 to 22. 6 % within 2 days (P = 0. 002), while, the percentage of sows with a fever was not decreased in sows treated with dipyrone. It can be concluded that the incidence of postparturient disorders in sows was affected by sow parity, farrowing duration and the type of anti-inflammatory drug used. Sows with a farrowing duration of ≥4 h were at a high risk of having fever at Day 1 after parturition. © 2012 Springer Science+Business Media Dordrecht.

Boonyaratanakornkit V.,Chulalongkorn University | Pateetin P.,Graduate Program in Clinical Biochemistry and Molecular Medicine
BioMed Research International | Year: 2015

Obese postmenopausal women have an increased risk of breast cancer and are likely to have a worse prognosis than nonobese postmenopausal women. The cessation of ovarian function after menopause results in withdrawal of ovarian sex steroid hormones, estrogen, and progesterone. Accumulating evidence suggests that the withdrawal of estrogen and progesterone causes homeostasis imbalances, including decreases in insulin sensitivity and leptin secretion and changes in glucose and lipid metabolism, resulting in a total reduction in energy expenditure. Together with a decrease in physical activity and consumption of a high fat diet, these factors significantly contribute to obesity in postmenopausal women. Obesity may contribute to breast cancer development through several mechanisms. Obesity causes localized inflammation, an increase in local estrogen production, and changes in cellular metabolism. In addition, obese women have a higher risk of insulin insensitivity, and an increase in insulin and other growth factor secretion. In this review, we describe our current understanding of the molecular actions of estrogen and progesterone and their contributions to cellular metabolism, obesity, inflammation, and postmenopausal breast cancer. We also discuss how modifications of estrogen and progesterone actions might be used as a therapeutic approach for obesity and postmenopausal breast cancer. © 2015 Viroj Boonyaratanakornkit and Prangwan Pateetin.

Limjirakan S.,Chulalongkorn University | Limsakul A.,Environmetal Research and Training Center Technopolis
Atmospheric Research | Year: 2012

One of the expected consequences of an anthropogenically warmed climate is the increase in evaporation. Paradoxically, terrestrial observations across the world show that the rates of pan evaporation (E pan) have been steadily decreasing since 1950s. In this study, we present a trend in Thailand E pan based on quality-controlled data from 28 weather stations from 1970 to 2007. Results indicated that, despite the annual mean air temperature increased by 0.91°C over the past 38years (0.024°C per annum), the trend in annual E pan has steadily declined on average by ~7.7mm a -2 (i.e. mm per annum per annum). By comparing, this change is larger than those previously reported for several countries. A further examination by Kendal's rank correlation and stepwise regression analysis based on some available weather data showed that reduction in wind speed and, to a lesser degree, sunshine duration were the likely causative meteorological factors affecting the E pan decrease in Thailand over the past 38years. The findings of this study highlight local changes in aerodynamic and radiative drivers of the hydrological cycle, and their linkages to climate change could have important implications for Thailand's nature and society. © 2012 Elsevier B.V.

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.

Hongladarom S.,Chulalongkorn University
Minds and Machines | Year: 2011

The emergence of social networking sites has created a problem of how the self is to be understood in the online world. As these sites are social, they relate someone with others in a network. Thus there seems to emerge a new kind of self which exists in the online world. Accounting for the online self here also has implications on how the self in the outside world should be understood. It is argued that, as the use of online social media has become more widespread, the line between the two kinds of self is becoming fuzzier. Furthermore, there seems to be a fusion between the online and the offline selves, which reflects the view that reality itself is informational. Ultimately speaking, both kinds of selves do not have any essence, i.e., any characteristic inherent to them that serves to show that these selves are what they are and none other. Instead an externalist account of the identity of the self is offered that locates the identity in question in the self's relations with other selves as well as other events and objects. This account can both be used to explain the nature of the self both in the online and the offline worlds. © Springer Science+Business Media B.V. 2011.

Aramwit P.,Bioactive Resources for Innovative Clinical Applications Research Unit | Towiwat P.,Chulalongkorn University | Srichana T.,Prince of Songkla University
Natural Product Communications | Year: 2013

Silk sericin was found to suppress the production of pro-inflammatory cytokines, which are related to the inflammatory reaction. The objectives of this study were to investigate the anti-inflammatory effect of sericin in vivo using the carrageenan-induced rat edema model and changes in the histology of tissues. The effects of sericin on the expression of COX-2 and iNOS were also evaluated. Sericin solutions at 0.004-0.080 mg/mL were applied topically to the top of the hind paw and carrageenan (1.0 mg) was injected subcutaneously to the plantar surface of the right hind paw. Our results indicated that sericin significantly reduced the inflammation in rats' paw compared with the negative control (water and acetone) and its effect at 0.080 mg/mL was only slightly lower than that of 1.0% w/v indomethacin. Similar numbers of polymorphonuclear and macrophage cells were found in rats' tissue treated with indomethacin and sericin solution, while the numbers were significantly higher in their absence. The gene expression results by RT-PCR showed that the COX-2 and iNOS genes were down-regulated in samples treated with sericin in a dose dependent manner. These data indicated that the anti-inflammatory properties of sericin may be partly attributable to the suppression of the COX-2 enzyme and nitric oxide production.

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.

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.

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.

The nitrosamine adsorbed on close-ended and open-ended pristine and Stone-Wales defective (5,5) armchair single-walled carbon nanotubes (SWCNTs) was studied using the B3LYP/6-31G(d) method. Structure optimization of all possible adsorption configurations based on the combination of two nitrosamine (amino- and imino-) isomers and four types of nanotubes was carried out. The most stable configuration for the nitrosamine adsorbed on the (5,5) armchair SWCNTs was found to be dissociative chemisorption. The adsorption energies of the most stable structures of the adsorption complexes of close-ended and open-ended pristine SWCNTs with the imino isomer of nitrosamine were -127.15 and -137.14 kcal mol-1, respectively. © Springer-Verlag 2009.

Prasarnphanich P.,Chulalongkorn University | Wagner C.,City University of Hong Kong
IEEE Transactions on Industrial Electronics | Year: 2011

This paper investigates the sustainability of a type of digital ecosystem, namely, knowledge-sharing communities built on the wiki model. Sustainability is hypothesized to result from the participation of contributors with varying levels of resources and interests. The differences in resources and interests, according to the critical-mass theory, enable such communities to overcome typical start-up and growth problems. This paper describes a preliminary empirical test of the critical-mass theory in this context, with Wikipedia as a test case that demonstrates sustainability as well as resource and interest heterogeneity, based on a survey of 78 Wikipedians. The characteristic patterns of success exhibited in Wikipedia are expected to inform the management of other wiki-based information assets. © 2009 IEEE.

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.

Thato R.,Chulalongkorn University | Penrose J.,University of Pittsburgh
Journal of Pediatric and Adolescent Gynecology | Year: 2013

Study Objective: To test the effectiveness of a brief theory-based HIV prevention program led by peers among college students. Design: A quasi-experimental research using a pretest-posttest nonequivalent control group design with 2-mo follow-up. Setting: A university in Bangkok. Participants: For peer leaders, 70 undergrad students taking health sexuality course were invited to participate in the study. Then, a convenience sample of undergraduate students was recruited through peer leaders, 226 for experimental group and 209 for control group. Main Outcome Measures: Information, motivation, behavioral skills, and AIDS/STIs preventive behaviors. Results: The study revealed that a Brief, Peer-Led HIV Prevention Program significantly increased knowledge of preventive behaviors (β = 2.67, P < .000), motivated participants to have a better attitude toward preventive behaviors (β = -5.26, P < .000), better subjective norms (β = -1.54, P < .000), and greater intentions to practice preventive behavior (β = -1.38, P < .000). The program also significantly decreased perceived difficulty of AIDS/STIs preventive behaviors (β = 2.38, P < .000) and increased perceived effectiveness at AIDS/STIs preventive behavior (β = -3.03, P < .000). However, it did not significantly increase AIDS/STIs preventive behaviors (β = 2.13, P > .05). Conclusion: Findings of this study provide initial evidence as to how theoretical variables were operated to effectively increase knowledge, change motivation, and behavioral skills of AIDS/STIs preventive behavior among Thai college students. More research is needed to further test the effectiveness of the program on AIDS/STIs preventive behaviors among college students. © 2013 North American Society for Pediatric and Adolescent Gynecology.

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.

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.

Hansarikit J.,Chulalongkorn University
Journal of the Medical Association of Thailand = Chotmaihet thangphaet | Year: 2011

To study the sensitivity and specificity of the modified 100-g oral glucose tolerance test for diagnosis of gestational diabetes mellitus (GDM). Medical records of pregnant women attending the antenatal clinic of King Chulalongkorn Memorial Hospital, Thailand, who underwent a 100-g oral glucose tolerance test (OGTT) during March 2004 to September 2009, were retrospectively reviewed. Three modified criteria were proposed for diagnosis of GDM. The screening efficacy of the modified criteria were assessed, using the National Diabetes Data Group (NDDG) criterion as gold standard. A total of 729 records were reviewed, 511 were included for analysis. Using the NDDG criterion as the gold standard, the modified II criterion has the highest sensitivity of 96.8%, and the highest accuracy of 90.8%. The modified II criterion can detect the same proportion of maternal and neonatal complications, compared to the NDDG criterion. The modified II criterion, using the fasting plasma glucose and 2-hour plasma glucose measurements, showed high sensitivity and accuracy, with moderate specificity for diagnosis of GDM. Its potential use as an alternative to standard 100-g OGTT should be evaluated in the prospective study.

Srisawat N.,Chulalongkorn University | Srisawat N.,University of Pittsburgh | Murugan R.,University of Pittsburgh | Kellum J.A.,University of Pittsburgh
Nephron - Clinical Practice | Year: 2014

Recent progress in biomarkers represents a paradigm shift in acute kidney injury (AKI) research. Most studies have evaluated the use of these biomarkers for early diagnosis of AKI. However, the role of novel biomarkers in predicting renal recovery, though less understood, holds great clinical promise. Accurate prediction would help physicians distinguish patients with poor renal prognosis in whom further therapy is unlikely to be useful from those who are likely to have good renal prognosis. Unfortunately, current general clinical severity scores (APACHE, SOFA, etc.) and AKI-specific severity scores are not good predictors of renal recovery. The biology of renal recovery requires the repopulation by surviving renal tubular epithelial cells with the assistance of certain renal epithelial cell and specific growth factors such as neutrophil gelatinase-associated lipocalin (NGAL), hepatocyte growth factor (HGF), epidermal growth factor, and insulin-like growth factor-1 (IGF-1), etc. These markers play a major role in the recovery process. This review will describe the mechanisms of the renal recovery, epidemiology, the role of conventional clinical predictors and finally the role of novel biomarkers (NGAL, HGF, IL-8, IL-18, TNFR-1, IGF-binding protein-7 and tissue inhibitor of metalloproteinase-2) in predicting renal recovery. © 2014 S. Karger AG, Basel.

Chuengsamarn S.,Srinakharinwirot University | Chuengsamarn S.,Brigham and Womens 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.

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.

Rudjanakanoknad J.,Chulalongkorn University
Transportation Research Record | Year: 2012

This paper offers a more complete picture of the capacity change mechanism at a diverge bottleneck caused by a queue from an exit ramp moving upstream onto the freeway. Detailed observations collected by videos during a 4-day period from an expressway in Bangkok, Thailand, showed that traffic states during bottleneck activation at the diverge site could be categorized into three distinct states with different levels of capacity according to vehicle speeds on through movement lanes and the rates of lane change maneuvers near the off-ramp queue. The data indicated that the transitions of traffic states were caused primarily by the changes in exit flows. The lower capacity was initiated by a more restrictive off-ramp flow that caused some cut-through vehicles on the adjacent lane to impede through movement traffic. Once the exit flow increased, impeding exit vehicles could move out of the adjacent through lane and higher capacity could be restored. These findings point to automatic off-ramp control strategies that would generate higher bottleneck capacities through detecting traffic speeds on freeway through lanes. These findings advance the present knowledge in traffic flow theory that will enable traffic researchers to understand more fully the traffic phenomena at a diverge bottleneck and will help traffic engineers to operate freeway traffic properly.

Thaiyuenwong J.,Chulalongkorn University
Journal of the Medical Association of Thailand = Chotmaihet thangphaet | Year: 2011

Peritoneal dialysis (PD) center is not possible to operate if there is no availability of dedicated PD nurse. Generally, the nurse has to play many roles, including educator coordinator, and sometimes leader. As professionalism, the PD nurses need to have both theoretical and practical skills. With the tremendous leap of PD population after the launch of "PD First" policy in Thailand, the shortage of skillful PD nurse is concerned. Hence, the nationwide PD nurse training course was established with the collaborations of many organizations and institutes. Until now, 3 generations of 225 PD nurses are the productions of the course. This number represents 80 percent of PD nurses distributed throughout the whole nation. The survey operated in the year 2010 demonstrated that the output of the course was acceptable in terms of quality since most of the trained PD nurses had a confidence in taking care of PD patients. The quality of patient care is good as indicated by KPIs.

Bunyavejchevin S.,Chulalongkorn University
Cochrane database of systematic reviews (Online) | Year: 2013

The surgical management of ovarian tumors in pregnancy is similar to that of non-pregnant women. The procedures include resection of the tumor (enucleation), removal of an ovary or ovaries (oophorectomy), or surgical excision of the fallopian tube and ovary (salpingo-oophorectomy). The procedure can be done by open surgery (laparotomy) or keyhole surgery (laparoscopy) technique. The benefits of laparoscopic surgery include shorter hospital stay, earlier return to normal activity, and reduced postoperative pain. However, conventional laparoscopic surgery techniques required the infusion of gas carbon dioxide in the peritoneum to distend the abdomen and displace the bowel upward to create the room for surgical manipulation. Serious complications such as abnormally high levels of carbon dioxide in the circulating blood (hypercarbia) and perforation of internal organs have also been reported. These serious complication may be harmful to the fetus. To compare the effects of using laparoscopic surgery for benign ovarian tumor during pregnancy on maternal and fetal health and the use of healthcare resources. We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 11 November 2012. Randomized controlled trials with reported data that compared outcomes of laparoscopic surgery for benign ovarian tumor in pregnancy to conventional laparotomy technique. Two review authors planned to independently assess trial quality and extract data. The updated search did not identify any randomized controlled trials. The practice of laparoscopic surgery for benign ovarian tumour during pregnancy is associated with benefits and harms. However, the evidence for the magnitude of these benefits and harms is drawn from case series studies, associated with potential bias. The results and conclusions of these studies must therefore be interpreted with caution.The available case series studies of laparoscopic surgery for benign ovarian tumour during pregnancy provide limited insight into the potential benefits and harms associated with this new surgical technique in pregnancy. Randomized controlled trials are required to provide the most reliable evidence regarding the benefits and harms of laparoscopic surgery for benign ovarian tumour during pregnancy.

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.

Sornkade P.,National Metal and Materials Technology Center | Atong D.,National Metal and Materials Technology Center | Sricharoenchaikul V.,Chulalongkorn University
Renewable Energy | Year: 2015

The air-gasification of cassava rhizome mixed with Ni/α-Al2O3 catalyst in a drop tube reactor for production of fuel gas was carried out in this work. The conversion was performed at different temperatures from 873 to 1073K, equivalence ratio (ER) of 0.2-0.6, and semi-continuous feeding of raw material for 30min. Gas yields, cold gas efficiency (CGE) and lower heating value of fuel gas (LHV) were compared with non-catalytic cases. Generally, higher temperature and ER significantly improved the performance of cassava rhizome gasification. Similar for both of non-catalytic and catalytic cases, at optimum temperature of 1073K and ER of 0.6, the maximum gas yields were closed to 80% while yields of char and tar were kept minimal at 4% and 11%, respectively. Addition of prepared catalysts resulted in greater CGE and LHV of 92% and 8.6MJ/Nm3, respectively, comparing to the non-catalytic case of 61% and 6.36MJ/Nm3, respectively. Moreover, the measured gas distribution data were comparable with the result obtained from thermodynamics conversion model based on minimization of Gibbs free energy of product gases using elemental composition of cassava rhizome (C3.13H5.2O3.52N0.03S0.04.) constrained by mass and energy balances for the system. As a result, the gas product distribution and characteristics obtained from this experimental implied its suitability for heat and power applications. © 2014 Elsevier Ltd.

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.

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.

Fuangarworn M.,Chulalongkorn University
Zootaxa | Year: 2011

Two new species of the oribatid mite family Protoplophoridae (Acari: Oribatida), Arthrhoplophora adjacentis sp. nov. and Protoplophora takensis sp. nov., collected from leaf litter of dry evergreen forest, are described and illustrated from Thailand. Arthrhoplophora adjacentis sp. nov. is unique in having the long ciliated rostral setae which are closely paired and bidactylous claws on pretarsi I, whereas pretarsi II-IV are tridactylous. Protoplophora takensis sp. nov. differs from its congeners by the presence of notogastral setae cp, seven pairs of genital setae and four-segmented palpi. Identification keys to species of Arthrhoplophora and Protoplophora are also provided. Copyright © 2011 Magnolia Press.

The serotonin transporter (5-HTT) is of great significance in the control of the serotonergic system, and its expression is known to be upregulated in psoriasis, a chronic or recurrent inflammatory skin disease. We investigated a possible association between the 5-HTT gene-linked polymorphic region (5-HTTLPR) and psoriasis in a Thai population. One hundred and fifty-six psoriatic patients and 156 unrelated healthy controls from Bangkok were genotyped using PCR. We found no overall differences in genotype distributions or allele frequencies between the two groups. In addition, when subgroups of psoriatic patients classified by either onset or severity were analyzed, no significant association between this polymorphism and any subgroup was observed. We conclude that 5-HTTLPR is not associated with susceptibility to psoriasis in this Thai population.

Haji-Akbari N.,University of Michigan | Teeraphapkul P.,Chulalongkorn University | Fogler H.S.,University of Michigan
Energy and Fuels | Year: 2014

Destabilized asphaltenes can easily adhere to the oil well production equipment, the transportation pipelines, and also the refining and storage facilities, resulting in significant remediation costs. Therefore, it is of great importance to the energy industry to understand the factors that govern the kinetics of asphaltene aggregation and precipitation. In this study, the effect of asphaltene concentration on their aggregation and precipitation tendencies after their destabilization with heptane is investigated for three different types of asphaltenes. It is intuitively expected that any increase in asphaltene concentration will accelerate the precipitation kinetics after heptane addition. For asphaltene concentrations below 1 wt % in toluene, this expected trend is indeed experimentally confirmed. However, for asphaltene concentrations above 1 wt %, an increase in concentration leads to slower aggregation instead. We believe that this counterintuitive decline in the aggregation rate is due to the stabilizing effect of stable or soluble asphaltenes. This effect has been overlooked in the existing aggregation models, and our research provides a better understanding of the factors controlling aggregation process. Accounting for the solubilizing effect of stable asphaltenes can provide successful predictions for the aggregation rate of asphaltenes at different asphaltene concentrations using Smoluchowski's model. © 2014 American Chemical Society.

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

We study N = 2 seven-dimensional gauged supergravity coupled to three vector multiplets with SO(4) gauge group. The resulting gauged supergravity contains 10 scalars consisting of the dilaton and 9 vector multiplet scalars parametrized by SO(3, 3)/SO(3)×SO(3) coset manifold. The maximally supersymmetric AdS 7 vacuum with unbroken SO(4) symmetry is identified with a (1, 0) SCFT in six dimensions. We find one new supersymmetric AdS 7 critical point preserving SO(3)diag ⊂ SO(3) × SO(3) ~ SO(4) and study a holographic RG flow interpolating between the SO(4) and the new SO(3) supersymmetric critical points. The RG flow is driven by a vacuum expectation value of a dimension-four operator and describes a deformation of the UV (1, 0) SCFT to another supersymmetric fixed point in the IR. In addition, a number of non-supersymmetric critical points are identified, and some of them are stable with all scalar masses above the BF bound. RG flows to non-conformal N = (1, 0) Super Yang-Mills with SO(2) × SO(2) and SO(2) symmetries are also investigated. Some of these flows have physically acceptable IR singularities since the scalar potential is bounded above. These provide physical RG flows from (1, 0) SCFT to non-conformal field theories in six dimensions. © 2014 The Author(s).

Srikham M.,Chulalongkorn University
Proceedings - International Conference on Pattern Recognition | Year: 2012

In this paper, we propose a novel active contour method for image segmentation, which utilizes the advantages of the GAC and the LRAC methods. We consider the smoothing force of the GAC method and local region-based force of the LRAC method. The advantages of our method are as follows. First the proposed method a new region-based signed pressure force function, which can efficiently stop the contours at weak boundary. Second the proposed method can be handle the heterogeneous texture objects and able to reach into deep concave shapes. Finally, the proposed formulation can be easily implemented by simple finite difference scheme and is computationally more efficient and accurate. The proposed method has been applied to both synthetic and real images. © 2012 ICPR Org Committee.

Manchana T.,Chulalongkorn University
Archives of Gynecology and Obstetrics | Year: 2011

Purpose To evaluate the risk factors of unsuccessful fitting of ring pessary in pelvic organ prolapse (POP), continuation rate, and adverse events. Methods The ring pessary was offered to 100 symptomatic POP patients. POP was staged according to Pelvic Organ Prolapse Quantification (POP-Q) system. A successful fitting was defined as when patients continued pessary use for more than 2 weeks. Adverse events were evaluated in patients who had a successful fitting. Results Most patients (71%) were in POP-Q stage III-IV and 77 patients were fitted at the initial visit. Successful fitting was reported in 62 patients (62%). However, 52 patients (52%) continued to use the pessary at 13 months median follow-up. The most common reason for discontinuation was frequent pessary expulsion. Short vaginal length ≤6 cm and wide introitus >4 fingerbreadths were the significant risk factors for unsuccessful fitting. New onset of stress urinary incontinence (SUI) developed in 28.2% of patients. One third and 21% of patients had vaginal discharge and vaginal erosion, respectively. Only half of the patients could manage the pessary either by themselves or with their caregivers. Conclusion The ring pessary fitting can be attempted in all POP cases irrespective of stage. Short vaginal length <6 cm and wide introitus >4 fingerbreadths were the risk factors for unsuccessful fitting. It has an acceptable continuation rate and manageable adverse events. The selfcare of pessary is an important strategy to minimize adverse events. © Springer-Verlag 2010.

Pichler J.,Medical University of Vienna | Chomtho S.,University College London | Chomtho S.,Chulalongkorn University | Fewtrell M.,University College London | And 2 more authors.
American Journal of Clinical Nutrition | Year: 2013

Background: Children with chronic intestinal failure (IF) treated with long-term parenteral nutrition (PN) may present with low bone mineral density (BMD). The cause may reflect small body size or suboptimal bone mineralization. Objective: We assessed growth and bone health in children with severe IF. Design: Height, weight, and fracture history were recorded. The lumbar spine bone mass was measured in 45 consecutive patients (24 male subjects) aged 5-17 y receiving PN for a median of 5 y. BMD and bone mineral apparent density (BMAD) [ie, adjusted-for-height SD scores (SDSs)] were calculated. Results: Diagnoses were short bowel syndrome in 12 patients (27%), intestinal enteropathy in 20 patients (44%), and motility disorder in 13 patients (29%). Mean (±SD) weight, height, and body mass index SDSs were -0.8 ± 1.3, -1.80 ± 1.5, and 0.4 ± 1.3, respectively. The height SDS was less than 22 in 23 children (50%). Patients with enteropathy or intestinal mucosal inflammation (associated with dysmotility or short bowel) were significantly shorter than patients without enteropathy (P = 0.007). The BMD SDS was -1.7 ± 1.6, and the BMAD SDS was -1.4 ± 1.5, independent of primary diagnosis or mucosal inflammation. Nineteen patients (42%) had low BMD (SDS less than -2.0), and 14 patients (31%) had low BMAD. In 25 patients studied at 1-2-y intervals, the BMD SDS fell significantly with time, whereas BMAD declined less, which suggested that a poor bone mineral accretion reflected poor growth. A total of 11 of 37 patients (24%) had nonpathologic fractures (P = 0.3 compared with the general population). Conclusions: Approximately 50% of children were short, and one-third of children had low BMD and BMAD. Children with enteropathy or intestinal mucosal inflammation are at greatest risk of growth failure. Close nutritional monitoring and bespoke PN should maximize the potential for growth and bone mass. © 2013 American Society for Nutrition.

We demonstrate strong evanescent wave amplification by a thin slab of uniaxial μ-near-zero (UMNZ) material. It is found that while retaining the same amplification effect, the slab can be made arbitrarily thin when the negative permeability along the axis of anisotropy approaches zero. Numerical results show that using a single layer of split-ring resonators (SRRs) with its thickness equal three thousandth of the incident wavelength (λ/3000), a subwavelength source distribution with λ/4 resolution can be transferred to a distance of λ/3. © 2014 Author(s).

Li Q.,University of Chicago | Wanderling S.,University of Chicago | Sompornpisut P.,Chulalongkorn University | Perozo E.,University of Chicago
Nature Structural and Molecular Biology | Year: 2014

Voltage-gated ion channels respond to transmembrane electric fields through reorientations of the positively charged S4 helix within the voltage-sensing domain (VSD). Despite a wealth of structural and functional data, the details of this conformational change remain controversial. Recent electrophysiological evidence showed that equilibrium between the resting ('down') and activated ('up') conformations of the KvAP VSD from Aeropyrum pernix can be biased through reconstitution in lipids with or without phosphate groups. We investigated the structural transition between these functional states, using site-directed spin-labeling and EPR spectroscopic methods. Solvent accessibility and interhelical distance determinations suggest that KvAP gates through S4 movements involving an ∼3-Å upward tilt and simultaneous ∼2-Å axial shift. This motion leads to large accessibly changes in the intracellular water-filled crevice and supports a new model of gating that combines structural rearrangements and electric-field remodeling. © 2014 Nature America, Inc. All rights reserved.

Burikham P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2010

We study the magnetic properties of the coloured multiquark states in the quark-gluon plasma where the gluons are deconfined and the chiral symmetry is still broken, using the Sakai-Sugimoto model. There are two possible magnetized multiquark configurations. Both configurations converge to the same configuration at the critical field and temperature before they dissociate altogether either into less coloured multiquarks or into other phases for a fixed density. It is also found that the multiquarks with higher colour charges respond more to the external magnetic field in both the magnetization and the degree of chiral symmetry breaking. Magnetic field also makes it more difficult for multiquark states with large colour charges to satisfy the equilibrium condition of the configuration in the gravity dual picture. As long as the chemical potential μ > μ onset, the magnetized multiquark phase is thermodynamically preferred over the magnetized vacuum. Pure pion gradient and the chiral-symmetric quark-gluon plasma (XS-QGP) phase for the general Sakai-Sugimoto model are discussed and compared with the multiquark phase in the presence of the magnetic field. It is found that at large densities and moderate fields, the mixed phase of multiquarks and the pion gradient is thermodynamically preferred over the XS-QGP. © SISSA 2010.

Ummartyotin S.,Thammasat University | Manuspiya H.,Chulalongkorn University
Renewable and Sustainable Energy Reviews | Year: 2015

The interest in cellulose and its modification as cellulose-based composite has been exponentially increasing. During the last three decades, cellulose and cellulose-based composite have been extensively designed for many aspects of the sensor. Due to the sustainability of cellulose and its excellent properties, the use of cellulose and the modification on cellulose-based composite can be versatile in the sensor community. In this review article, fundamental and background of cellulose and modification of cellulose-based composite are presented. Numerous approaches on cellulose and cellulose-based composite for many types of sensors including gas sensor, humidity sensor, UV sensor, strain sensor as well as capacitive sensor were discussed. © 2014 Elsevier Ltd.

Tienthai P.,Chulalongkorn University
Journal of Reproduction and Development | Year: 2015

The oviduct plays a role in successful animal reproduction not only in spermatozoa and ova transport to the fertilization site but also by affording a microenvironment for fertilization and early embryonic development. The sperm reservoir (SR) is restricted in the uterotubal junction (UTJ) and caudal isthmus. Billions of porcine spermatozoa are distributed to the female reproductive tract during/after insemination, and small amounts of them are stored for about 36–40 hours in the SR, which maintains sperm viability in the pre-ovulation period through its surface epithelium and production of fluid. The SR regulates the release of spermatozoa so that only a small population moves towards the fertilization site (ampulla) to decrease polyspermy. This review attempts to provide information about the structure and function of the porcine SR, its intraluminal content (hyaluronan, HA), and the influences of HA on porcine spermatozoa in vivo. In pigs, the spermatozoa are stored in a mucous-like fluid within the UTJ and caudal isthmus in the pre-ovulation period. The oviduct fluid contains sulfated glycosaminoglycans (GAGs) and non-sulfated GAGs, i.e., HA. It is interesting to note that HA is synthesized by hyaluronan synthase-3 (HAS-3), and its receptor, CD44, is found in the epithelium of the porcine SR site. Additionally, sperm capacitation does not occur in vivo in the SR during the pre- and peri-ovulation periods, but spermatozoa in the SR will attempt to capacitate if exposed to bicarbonate. However, capacitation in the SR will rise in the post-ovulation period, indicating the role of HA in modulating sperm capacitation after ovulation. All data support the understanding that the porcine SR ensures the viability of fertile spermatozoa and maintains the non-capacitated status during the pre-ovulation period. This basic knowledge about the SR is believed to be useful to advance sperm preparation procedures for in vitro fertilization (IVF) and improve the preservation process of porcine semen. © 2015 by the Society for Reproduction and Development.

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.

Srisawat N.,University of Pittsburgh | Srisawat N.,Chulalongkorn University | Kellum J.A.,University of Pittsburgh
Current Opinion in Critical Care | Year: 2011

Purpose of review: Acute kidney injury (AKI) is a common clinical syndrome whose definition has standardized as a result of consensus by leading experts around the world. As a result of these definitions, reported AKI incidences can now be compared across different populations and settings. Evidence from population-based studies suggests that AKI is nearly as common as myocardial infarction, at least in the western world. This review aims to highlight the recent advances in AKI epidemiology as well as to suggest future directions for prevention and management. Recent findings: This review will focus on the recent studies exploring the AKI epidemiology in and outside the ICU. In particular, the risk of AKI in less severe sepsis is notable as is evidence linking AKI to chronic kidney disease. New emphasis on renal recovery is shaping current thinking as is the use and utility of new biomarkers. Summary: This article reviews the recent information about the definition, classification, and epidemiology of AKI. Although new biomarkers are being developed, the 'tried and true' markers of serum creatinine and urine output, disciplined by current criteria, will be important components in the definition and classification of AKI for some time to come. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Tangjitsitcharoen S.,Chulalongkorn University
Journal of Intelligent Manufacturing | Year: 2011

This paper presents an advance in detection of cutting states of the previous work to increase the capability of CNC turning process. A proposed method has been improved and developed to monitor and detect the cutting states based on proposed pattern recognition technique for CNC turning process within the small data-processing time by utilizing the dynamic cutting forces. The proposed method introduces three parameters, which are obtained by taking the ratio of the average variances of the dynamic cutting forces, to classify the cutting states of the continuous chip, the broken chip, the mixed broken chip, the chatter and the chatter occurred with broken chip. Among those cutting states, the broken chip and the mixed broken chip are required to improve the stability and capability of turning process. The algorithm was developed to calculate the values of three parameters in order to obtain the three-dimensional reference feature spaces and the proper threshold values for identification of the cutting states. An improvement of the proposed method is proved by series of cutting tests that the states of cutting are well detected regardless of any cutting conditions. The broken chips are obtained easily by changing the cutting conditions during the process. Finally, the effect of cutting conditions on the morphology of chips is also discussed. © Springer Science+Business Media, LLC 2009.

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.

Osathanon T.,Chulalongkorn University
International journal of oral science | Year: 2010

The aim of this article was to examine the research articles regarding biological and mechanical properties of cryopreserved teeth for potential use in tooth transplantation. A systematic review of literatures was performed by Pubmed searching with assigned key words from January 1, 1990 to June 8, 2009. All articles were examined for inclusion criteria. Secondary search was conducted by hand-search through references of included articles from primary search. A total of 24 articles were obtained from both primary and secondary search and used as fundamental articles in this review. Periodontal ligament tissues of cryopreserved teeth were able to maintain their biological properties resulted in a satisfactory healing of periodontium. Dental pulp tissues, however, may be compromised by limitation of permeability of cryopreservative agent into pulp cavity. Therefore, an endodontic treatment of transplanted cryopreserved teeth was recommended. Cryopreserved teeth had comparable mechanical properties to those of normal teeth. Importantly, the success of cryopreserved tooth transplantation treatment in orthodontic patients was reported. The cryopreserved teeth for tooth banking have a potential clinical application for treatment of missing teeth. Case selection, however, is critical for treatment success. More studies and data regarding masticatory function and periodontal healing of transplanted cryopreserved teeth are needed.

Prongjit M.,Mahidol University | Sucharitakul J.,Chulalongkorn University | Palfey B.A.,University of Michigan | Chaiyen P.,Mahidol University
Biochemistry | Year: 2013

Pyranose 2-oxidase (P2O) from Trametes multicolor is a flavoenzyme that catalyzes the oxidation of d-glucose and other aldopyranose sugars at the C2 position by using O2 as an electron acceptor to form the corresponding 2-keto-sugars and H2O2. In this study, the effects of pH on the oxidative half-reaction of P2O were investigated using stopped-flow spectrophotometry. The results showed that flavin oxidation occurred via different pathways depending on the pH of the environment. At pH values lower than 8.0, reduced P2O reacts with O2 to form a C4a-hydroperoxyflavin intermediate, leading to elimination of H 2O2. At pH 8.0 and higher, the majority of the reduced P2O reacts with O2 via a pathway that does not allow detection of the C4a-hydroperoxyflavin, and flavin oxidation occurs with decreased rate constants upon the rise in pH. The switching between the two modes of P2O oxidation is controlled by protonation of a group which has a pKa of 7.6 ± 0.1. Oxidation reactions of reduced P2O under rapid pH change as performed by stopped-flow mixing were different from the same reactions performed with enzyme pre-equilibrated at the same specified pH values, implying that the protonation of the group which controls the mode of flavin oxidation cannot be rapidly equilibrated with outside solvent. Using a double-mixing stopped-flow experiment, a rate constant for proton dissociation from the reaction site was determined to be 21.0 ± 0.4 s-1. © 2013 American Chemical Society.

Kaewkongka T.,Chulalongkorn University
Engineering Solid Mechanics | Year: 2016

This article provides a method of acoustic emission (AE) technique to detect leakage in pipeline and locate the position of the leakage. The AE sensor is made of piezoelectric effect transducer to pick up the acoustic emission signal which is generated from the turbulent flow at the leak position. The signal conditioning unit is used to enhanced and eliminate the background noise from the leak location sources. The main acoustic emission processing unit is used to acquire and process the extracted AE characteristic parameters from preprocessing waveform. The leak pipeline is simulated by drilling the hole and plugged with M8 screw at different locations. The results show that the proposed AE method can detect and locate simultaneous leak condition in pipeline with promising results. © 2016 Growing Science Ltd. All rights reserved.

Kraiwattanawong K.,King Mongkuts 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.

Pailoplee S.,Chulalongkorn University
Terrestrial, Atmospheric and Oceanic Sciences | Year: 2014

This study investigates the present-day seismicity along the strike-slip fault system on the Thailand-Myanmar border. Using the earthquake catalogue the earthquake parameters representing seismic activities were evaluated in terms of the possible maximum magnitude, return period and earthquake occurrence probabilities. Three different hazardous areas could be distinguished from the obtained results. The most seismic-prone area was located along the northern segment of the fault system and can generate earthquakes of magnitude 5.0, 5.8, and 6.8 mb in the next 5, 10, and 50 years, respectively. The second most-prone area was the southern segment where earthquakes of magnitude 5.0, 6.0, and 7.0 mb might be generated every 18, 60, and 300 years, respectively. For the central segment, there was less than 30 and 10 probability that 6.0- and 7.0-mb earthquakes will be generated in the next 50 years. With regards to the significant infrastructures (dams) in the vicinity, the operational Wachiralongkorn dam is situated in a low seismic hazard area with a return period of around 30-3000 years for a 5.0-7.0 mb earthquake. In contrast, the Hut Gyi, Srinakarin and Tha Thung Na dams are seismically at risk for earthquakes of mb 6.4-6.5 being generated in the next 50 years. Plans for a seismic-retrofit should therefore be completed and implemented while seismic monitoring in this region is indispensable.

Chareonlimkun A.,King Mongkuts University of Technology Thonburi | Champreda V.,National Center for Genetic Engineering and Biotechnology | Shotipruk A.,Chulalongkorn University | Laosiripojana N.,King Mongkuts 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.

Sanghangthum T.,Chulalongkorn University
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2013

Shewhart control charts have previously been suggested as a process control tool for use in routine linear accelerator (linac) output verifications. However, a comprehensive approach to process control has not been investigated for linac output verifications. The purpose of this work is to investigate a comprehensive process control approach to linac output constancy quality assurance (QA). The RBA-3 dose constancy check was used to verify outputs of photon beams and electron beams delivered by a Varian Clinac 21EX linac. The data were collected during 2009 to 2010. Shewhart-type control charts, exponentially weighted moving average (EWMA) charts, and capability indices were applied to these processes. The Shewhart-type individuals chart (X-chart) was used and the number of data points used to calculate the control limits was varied. The parameters tested for the EWMA charts (smoothing parameter (λ) and the control limit width (L)) were λ = 0.05, L = 2.492; λ = 0.10, L = 2.703; and λ = 0.20, L = 2.860, as well as the number of points used to estimate the initial process mean and variation. Lastly, the number of in-control data points used to determine process capability (C(p)) and acceptability (C(pk)) were investigated, comparing the first in-control run to the longest in-control run of the process data. C(p) and C(pk) values greater than 1.0 were considered acceptable. The 95% confidence intervals were reported. The X-charts detected systematic errors (e.g., device setup errors). In-control run lengths on the X-charts varied from 5 to 30 output measurements (about one to seven months). EWMA charts showed in-control runs ranging from 9 to 33 output measurements (about two to eight months). The C(p) and C(pk) ratios are higher than 1.0 for all energies, except 12 and 20 MeV. However, 10 MV and 6, 9, and 16 MeV were in question when considering the 95% confidence limits. The X-chart should be calculated using 8-12 data points. For EWMA chart, using 4 data points is sufficient to calculate the initial mean and variance of the process. The EWMA limits should be calculated with λ = 0.10, L = 2.703. At least 25-30 in-control data points should be used to calculate the C(p) and C(pk) indices.

Vchirawongkwin V.,Chulalongkorn University | Kritayakornupong C.,King Mongkuts 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.

Although, increased oxidative stress and hypomethylation of long interspersed nuclear element-1 (LINE-1) associate with bladder cancer (BCa) development, the relationship between these alterations is unknown. We evaluated the oxidative stress and hypomethylation of the LINE-1 in 61 BCa patients and 45 normal individuals. To measure the methylation levels and to differentiate the LINE-1 loci into hypermethylated, partially methylated and hypomethylated, peripheral blood cells, urinary exfoliated cells and cancerous tissues were evaluated by combined bisulfite restriction analysis PCR. The urinary total antioxidant status (TAS) and plasma protein carbonyl content were determined. The LINE-1 methylation levels and patterns, especially hypomethylated loci, in the blood and urine cells of the BCa patients were different from the levels and patterns in the healthy controls. The urinary TAS was decreased, whereas the plasma protein carbonyl content was increased in the BCa patients relative to the controls. A positive correlation between the methylation of LINE-1 in the blood-derived DNA and urinary TAS was found in both the BCa and control groups. The urinary hypomethylated LINE-1 loci and the plasma protein carbonyl content provided the best diagnostic potential for BCa prediction. Based on post-diagnostic samples, the combination test improved the diagnostic power to a sensitivity of 96% and a specificity of 96%. In conclusion, decreased LINE-1 methylation is associated with increased oxidative stress both in healthy and BCa subjects across the various tissue types, implying a dose-response association. Increases in the LINE-1 hypomethylation levels and the number of hypomethylated loci in both the blood- and urine-derived cells and increase in the oxidative stress were found in the BCa patients. The combination test of the urinary hypomethylated LINE-1 loci and the plasma protein carbonyl content may be useful for BCa screening and monitoring of treatment.

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.

Kiatpongsan S.,Harvard Interfaculty Initiative in Health Policy | Kiatpongsan S.,Chulalongkorn University | Campos N.G.,Center for Health Decision Science | Kim J.J.,Center for Health Decision Science
PLoS ONE | Year: 2012

Background: Current prophylactic vaccines against human papillomavirus (HPV) target two oncogenic types (16 and 18) that contribute to 70% of cervical cancer cases worldwide. Our objective was to quantify the range of additional benefits conferred by second-generation HPV prophylactic vaccines that are expected to expand protection to five additional oncogenic types (31, 33, 45, 52 and 58). Methods: A microsimulation model of HPV and cervical cancer calibrated to epidemiological data from two countries (Kenya and Uganda) was used to estimate reductions in lifetime risk of cervical cancer from the second-generation HPV vaccines. We explored the independent and joint impact of uncertain factors (i.e., distribution of HPV types, co-infection with multiple HPV types, and unidentifiable HPV types in cancer) and vaccine properties (i.e., cross-protection against non-targeted HPV types), compared against currently-available vaccines. Results: Assuming complete uptake of the second-generation vaccine, reductions in lifetime cancer risk were 86.3% in Kenya and 91.8% in Uganda, representing an absolute increase in cervical cancer reduction of 26.1% in Kenya and 17.9% in Uganda, compared with complete uptake of current vaccines. The range of added benefits was 19.6% to 29.1% in Kenya and 14.0% to 19.5% in Uganda, depending on assumptions of cancers attributable to multiple HPV infections and unidentifiable HPV types. These effects were blunted in both countries when assuming vaccine cross-protection with both the current and second-generation vaccines. Conclusion: Second-generation HPV vaccines that protect against additional oncogenic HPV types have the potential to improve cervical cancer prevention. Co-infection with multiple HPV infections and unidentifiable HPV types can influence vaccine effectiveness, but the magnitude of effect may be moderated by vaccine cross-protective effects. These benefits must be weighed against the cost of the vaccines in future analyses. © 2012 Kiatpongsan et al.

Kanlayanaphotporn R.,Chulalongkorn University
Journal of Bodywork and Movement Therapies | Year: 2014

Objective: To assess the effect of slouched sitting on shoulder range of motion (ROM). Method: 30 asymptomatic males aged between 18 and 35 years with no history of shoulder problems within the last 6 months. Shoulder ROMs in flexion and abduction as well as external rotation and internal rotation in 90° of shoulder abduction were measured while the subjects sat in 3 different sitting postures. Results: There were statistically significant mean differences among the 3 sitting postures regarding thoracic kyphosis and shoulder ROMs (p<0.001). Post hoc analyzes demonstrated significant differences in all comparisons (p<0.001). Conclusion: Changes in sitting posture affect shoulder ROMs in all directions tested. Greater changes in shoulder ROMs were associated with greater increase in thoracic kyphosis. These findings suggest that even subtle changes in thoracic kyphosis need to be considered during shoulder evaluation. © 2013 Elsevier Ltd.

Srimuninnimit V.,University of Sfax | Sriuranpong V.,Chulalongkorn University | Suwanvecho S.,Bumrungrad International Hospital
Asia-Pacific Journal of Clinical Oncology | Year: 2014

Aims: Currently, the only standard systemic treatment for advanced hepatocellular carcinoma is sorafenib monotherapy. The study was conducted to assess the efficacy and safety of the novel combination of sorafenib and gemcitabine in the treatment of advanced hepatocellular carcinoma. Methods: Between March 2008 and October 2010, patients with advanced pathologically proven hepatocellular carcinoma who had not received previous systemic therapy and had Child-Pugh liver function class A or B received sorafenib plus gemcitabine. Treatment included 4-week cycle of gemcitabine (1000mg/m2 days 1, 8, 15) to the maximum of six cycles together with sorafenib (400mg twice daily). Patient continued sorafenib until disease progression or withdrawal from other reasons. The primary end point is progression-free survival. Results: Forty-five patients were enrolled in this study. The median progression-free survival was 3.7 months (95% CI 3.5-3.8). The overall response rate was 4% with no complete responses and the disease control rate was 66%. The median overall survival (OS) was 11.6 months (95% CI 7.4-15.9). The median time to progression was 3.6 months (95% CI 3.4-3.7). The most frequently reported grade 3/4 treatment-related adverse events included thrombocytopenia 33%, neutropenia 16% and hand-foot skin reaction 13%. The study regimen was well tolerated. Conclusion: The combination of sorafenib and gemcitabine in advanced hepatocellular carcinoma is generally well tolerated and has modest clinical efficacy. The median OS is up to 1 year. However, well-designed randomized controlled trials with a sorafenib alone comparator arm are needed to confirm this finding. © 2014 Wiley Publishing Asia Pty Ltd.

Manothum A.,Chulalongkorn University
Journal of injury & violence research | Year: 2010

This study aims to promote occupational health in the informal sector in Thailand by using a participatory approach. The success of the intervention is based on an evaluation of the informal sector workers, a) knowledge, attitudes, and behaviors in occupational health and safety, b) work practice improvement, and c) working condition improvement. This study applies the Participatory Action Research (PAR) method. The participants of the study consisted of four local occupations in different regions of Thailand, including a ceramic making group in the North, a plastic weaving group in the Central region, a blanket making group in the Northeast, and a pandanus weaving group in the South. Data was collected using both qualitative and quantitative methods through questionnaires, industrial hygiene instruments, and group discussions. The results showed that the working conditions of the informal sector were improved to meet necessary standards after completing the participatory process. Also, the post-test average scores on 1) the occupational health and safety knowledge, attitudes and behaviors measures and 2) the work practice improvement measures were significantly higher than the pre-test average scores (P less than 0.05). The results demonstrate that the participatory approach is an effective tool to use when promoting the health safety of the informal sector and when encouraging the workers to voluntarily improve the quality of their own lives.

we aimed at determining the incidence and factors for TDF-associated renal function decline among Thai HIV-infected patients. retrospective and prospective cohort studies were conducted. We enrolled HIV-infected adults who had initiated TDF. Renal function decline that was defined by a decrease of 25% in glomerular filtration rate (GFR) from the baseline. Factors associated with the renal function decline were determined. a total of 405 patients with a median (IQR) body weight of 56.5 (50.5-65.0) kg were enrolled. All but four (99%) were antiretroviral treatment-experience patients. A median (IQR) duration of receiving TDF was 16 (8-21) months. Of these, 78 (19.3%) patients had a 25% decrease in GFR with the incidence rate of 16.2 per 100 person-years. By Kaplan-Meier survival analysis, median time to a 25% decrease in GFR was 28 [95% confidence interval (CI) 25.2-30.8] months. By multiple logistic regression, lower body weight [odds ratio (OR) 1.15 per 5 kg, 95% CI 1.00-1.33], lower body mass index (BMI) (OR 2.26 per 1 kg/m(2), 95% CI 1.74-2.94), baseline GFR (OR 1.62 per 10 ml/min/1.73m(2), 95% CI 1.39-1.88), protease inhibitor (OR 2.12, 95% CI 1.15-3.92), and nephrotoxic drug (OR 3.16, 95% CI 1.44-6.98) were statistically significant factors associated with a 25% decrease in GFR. the study revealed high incidence of TDF-associated renal function decline among patients with low-body weight and BMI. Additional risk factors were baseline GFR, receiving protease inhibitor, and nephrotoxic drugs. Close monitoring of renal function is warranted among patients with these risk factors.

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.

Tummaruk P.,Gynaecology and Reproduction | Tienthai P.,Chulalongkorn University
Reproduction in Domestic Animals | Year: 2010

The aim of this study was to investigate the number of spermatozoa in the crypts of the utero-tubal junction (UTJ) and the oviduct of sows approximately 24 h after intrauterine insemination (IUI) and deep intrauterine insemination (DIUI) and compared with that of conventional artificial insemination (AI). Fifteen crossbred Landrace × Yorkshire (LY) multiparous sows were used in the experiment. Transrectal ultrasonography was performed every 4 h to examine the time of ovulation in relation to oestrous behaviour. The sows were inseminated with a single dose of diluted fresh semen by the AI (n = 5), IUI (n = 5) and DIUI (n = 5) at approximately 6-8 h prior to the expected time of ovulation, during the second oestrus after weaning. The sperm dose contained 3000 × 106 spermatozoa in 100 ml for AI, 1,000 × 106 spermatozoa in 50 ml for IUI and 150 × 106 spermatozoa in 5 ml for DIUI. The sows were anaesthetized and ovario-hysterectomized approximately 24 h after insemination. The oviducts and the proximal part of the uterine horns (1 cm) on each side of the reproductive tracts were collected. The section was divided into four parts, i.e. UTJ, caudal isthmus, cranial isthmus and ampulla. The spermatozoa in the lumen in each part were flushed several times with phosphate buffer solution. After flushing, the UTJ and all parts of the oviducts were immersed in a 10% neutral buffered formalin solution. The UTJ and each part of the oviducts were cut into four equal parts and embedded in a paraffin block. The tissue sections were transversely sectioned to a thickness of 5 μm. Every fifth serial section was mounted and stained with haematoxylin and eosin. The total number of spermatozoa from 32 sections in each parts of the tissue (16 sections from the left side and 16 sections from the right side) was determined under light microscope. The results reveal that most of the spermatozoa in the histological section were located in groups in the epithelial crypts. The means of the total number of spermatozoa in the sperm reservoir (UTJ and caudal isthmus) were 2296, 729 and 22 cells in AI, IUI and DIUI groups, respectively (p < 0.01). The spermatozoa were found on both sides of the sperm reservoir in all sows in the AI and the IUI groups. For the DIUI group, spermatozoa were not found on any side of the sperm reservoir in three out of five sows, found in unilateral side of the sperm reservoir in one sow and found in both sides of the sperm reservoir in one sow. No spermatozoa were found in the cranial isthmus, while only one spermatozoon was found in the ampulla part of a sow in the IUI group. In conclusion, DIUI resulted in a significantly lower number of spermatozoa in the sperm reservoir approximately 24 h after insemination compared with AI and IUI. Spermatozoa could be obtained from both sides of the sperm reservoir after AI and IUI but in one out of five sows inseminated by DIUI. © 2008 The Authors. Journal compilation © 2008 Blackwell Verlag.

Tananuwong K.,Chulalongkorn University | Lertsiri S.,Mahidol University
Journal of the Science of Food and Agriculture | Year: 2010

BACKGROUND: Aroma of fragrant rice greatly affects palatability as well as consumer acceptability. Loss of desirable volatile compounds such as 2-acetyl-1-pyrroline (2-AP) and increase in volatile lipid oxidation products in aged rice have been reported. The aim of this study was to monitor the changes in key volatile compounds of organic red fragrant rice cv. Hom Daeng during storage. Effects of packaging material, storage temperature and time were evaluated using solid phase microextraction/gas chromatography/mass spectrometry. RESULTS: Thirteen key volatile compounds including ten lipid oxidation productsweremonitored. For samples vacuum packed in Nylon/LLDPE pouches at ambient temperature, significant increases in hexanal, 2-pentylfuran, 1-octanol and 4-vinyl guaiacol and significant decreases in 2-AP and geranyl acetone were found after the second month (P ≤ 0.05). Vacuum packing in OPP/Al/LLDPE pouchesor storage at 15 ° Cbetter retarded the formationof volatile lipid oxidationproducts andgreater retained desirable odorants, including 2-AP. However, accumulation of lipid oxidation products and 4-vinyl guaiacol was apparent after the sixth month under these storage conditions. CONCLUSION: A greater extent and higher rate of undesirable changes in volatile compounds were found in samples stored under Nylon/LLDPE/ambient temperature condition. Nevertheless, this condition is acceptable for the retail trade of organic rice in Thailand. Storage conditions using reduced temperature or better packaging materials may be more appropriate for exported rice or superior-grade fragrant rice to better maintain the desirable rice aroma. © 2010 Society of Chemical Industry.

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

Abstract: We construct a consistent reduction ansatz of eleven-dimensional supergravity to N =2 SO(4) seven-dimensional gauged supergravity with topological mass term for the three-form field. The ansatz is obtained from a truncation of the S4 reduction giving rise to the maximal N =4 SO(5) gauged supergravity. Therefore, the consistency is guaranteed by the consistency of the S4 reduction. Unlike the gauged supergravity without topological mass having a half-supersymmetric domain wall vacuum, the resulting 7D gauged supergravity theory admits a maximally supersymmetric AdS7 critical point. This corresponds to N = (1, 0) superconformal field theory in six dimensions. We also study RG flows from this N = (1, 0) SCFT to non-conformal N = (1, 0) Super Yang-Mills theories in the seven-dimensional framework and use the reduction ansatz to uplift this RG flow to eleven dimensions. © 2014, The Author(s).

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).

Tongsopit S.,Chulalongkorn University | Greacen C.,Palang Thai
Renewable Energy | Year: 2013

Thailand was one of the first Asian countries with a comprehensive feed-in tariff program, with streamlined interconnection regulations adopted by the Thai Cabinet in 2002 and technology-specific tariff 'Adders' in 2006. This paper presents an overview of the country's feed-in tariff, or Adder, program and its development. As of December 2011, Thailand has about 8000MW of renewable energy projects in the pipeline seeking Adder and about 1000MW already connected and selling power to the grid. Thailand's feed-in tariff program has undergone significant transitions especially since 2010 in tariff levels and screening criteria partly in response to applications for 471 solar electric power plants exceeding 2000MW. A powerful new oversight committee comprising utility and Ministry of Energy representatives has raised concerns regarding transparency and consistency, and significantly reduced approval rates of new applications. © 2013 Elsevier Ltd.

This study aimed to examine the extent to which income-related inequality and horizontal inequity in outpatient and inpatient care utilization among Thais are manifest after the country implemented the Universal Coverage (UC) policy, by using a concentration index and a horizontal inequity index, respectively. Furthermore, the study examined the determinants and their associations with the observed inequality, if any, in health care utilization through decomposition methods. The nationally representative Health and Welfare Survey 2005 was used to perform the analyses. Although there are socioeconomic gradients in health care utilization among Thais, the findings reveal that health care utilization tends to favor the poor in particular with utilization at the public facility and especially at the primary care level facility. Thailand has made impressive strides toward nearly universal health insurance coverage and improving access to and utilization of health care for its population, particularly among the poor. © 2011 Asia-Pacific Academic Consortium for Public Health.

Mwaura J.W.,Chulalongkorn University
The Pan African medical journal | Year: 2012

Out-of-pocket payments create financial barriers to health care access. There is an increasing interest in the role of community based health insurance schemes in improving equity and access of the poor to essential health care. The aim of this study was to assess the impact of Jamii Bora Health Insurance on access to health care among the urban poor. Data was obtained from the household health interview survey in Kibera and Mathare slums, which consisted of 420 respondents, aged 18 and above who were registered as members of Jamii Bora Trust. The members of Jamii Bora Trust were divided into two groups the insured and the non-insured. In total, 17.9% respondents were hospitalized and women (19.6%) were more likely to be admitted than men (14.7%). Those in the poorest quintile had the highest probability of admission (18.1%). Those with secondary school education, large household size, and aged 50 and above also had slightly greater probability of admission (p<0.25). 86% of admissions among the insured respondents were covered JBHI and those in the poorest quintile were more likely to use the JBHI benefit. Results from the logistic regression revealed that the probability of being admitted, whether overall admission or admission covered by the JBHI benefit was determined by the presence of chronic condition (p<0.01). Utilization and take up of the JBHI benefits was high. Overall, JBHI favoured the members in the lower income quintiles who were more likely to use health care services covered by the JBHI scheme.

BACKGROUND: This study evaluated the biocompatibilities of random and putative block poly(3-hydroxybutyrate-co-3-hydroxyvalerate)s (PHBVs) produced by a metabolic reaction-based system. The produced PHBVs were fractionated, and the copolymer sequence distributions were analyzed using (1)H and (13)C NMR spectroscopy. The thermal properties were analyzed using differential scanning calorimetry (DSC). Mechanical tests were conducted using a universal testing machine. The in vitro cytotoxicities of films composed of random PHBVs and putative block PHBVs were investigated against three types of mammalian cells. The surfaces of the copolymer films and the morphologies of the cells were qualitatively monitored using scanning electron microscopy (SEM) and atomic force microscopy (AFM).RESULTS: Films composed of poly(3-hydroxybutyrate) (PHB), random PHBVs, putative block PHBVs, polystyrene and polyvinylchloride were prepared and characterized. The diad and triad sequence distributions indicated that the PHBVs produced via the fed-batch cultivation using two different feed systems resulted in two types of copolymers: random PHBVs and putative block PHBVs. The monomer compositions and sequence distributions strongly affected the thermal and mechanical properties. The mechanical integrity and characteristics of the film surfaces changed with the HV content. Notably, the random PHBVs possessed different mechanical properties than the putative block PHBVs. The biocompatibilities of these films were evaluated in vitro against three types of mammalian cells: L292 mouse connective tissue, human dermal fibroblast and Saos-2 human osteosarcoma cells. None of the PHBV films exhibited cytotoxic responses to the three types of mammalian cells. Erosion of the PHA film surfaces was observed by scanning electron microscopy and atomic force microscopy. The production of transforming growth factor-β-1 and interleukin-8 was also examined with regards to the usefulness of PHB and PHBV as biomaterials for regenerative tissue. The production of IL-8, which is induced by PHB and PHBVs, may be used to improve and enhance the wound-healing process because of deficiencies of IL-8 in the wound area, particularly in problematic wounds.CONCLUSION: Taken together, the results support the use of PHB and the random and putative block PHBVs produced in this study as potential biomaterials in tissue engineering applications for connective tissue, bone and dermal fibroblast reconstruction.

Pitakwatchara P.,Chulalongkorn University
IEEE International Conference on Intelligent Robots and Systems | Year: 2015

A novel control scheme based on wave variables for controlling the teleoperation system over the time-varying delayed communication is proposed. Regarding to the symmetric wave teleoperation control layout, the control is achieved by adjusting the wave variables based on the difference between the desired and the fictitious position, which is obtained from integrating the non-distorted wave variables. The resulting wave is then applied to the master/slave robots controlled with local PD controller. By this control scheme, the system is stable and the position difference of the master and slave is proven to converge to zero in the free motion case if the time delay is continuously differentiable. In addition, the slave-environment interaction force is reflected to the operator precisely when the static contact is made during steady time delay. This control scheme can readily be extended to the implementation of the teleoperation system in full task space SO(3) ×3. © 2015 IEEE.

Laosiripojana N.,King Mongkuts 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.

Arpornwichanop A.,Chulalongkorn University | Patcharavorachot Y.,King Mongkuts 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.

This retrospective study was carried out to estimate the prevalence of an adrenal crisis at a provincial hospital in Thailand over a period of 1 year, and also to explore the relationship between adrenal insufficiency and over-the-counter medicine (OTCM) ingestion. We recruited those patients admitted at Sisaket Hospital between October 2012 and October 2013 who were diagnosed with shock and adrenal insufficiency or adrenal crisis. Of 2,435 patients diagnosed with shock from all causes, 62 (2.55 %) were diagnosed with adrenal crisis, of whom 31 (50.0%) gave a history of OTCM ingestion. This study suggests adrenal crisis with shock is not that uncommon and that the use of OTCM may be the prime culprit. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

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.

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.

Dangtungee R.,King Mongkuts 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.

Trinavarat P.,Chulalongkorn University | Riccabona M.,University of Graz
European Journal of Radiology | Year: 2014

Ultrasound (US) of chest, even with inherent limitations of the US beam and air, has been useful in many pediatric chest conditions. It has extended its role and is now widely used by many subspecialists in medicine. This review article will cover techniques, indications, and applications of chest US in neonates, infants and children, including also different common as well as some rare and modern aspects and applications, such as pleural effusion, pneumothorax, pulmonary lesions, mediastinum, diaphragm, and chest wall. Other related imaging modalities are also briefly discussed. © 2014 Elsevier Ireland Ltd.

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.

Ludington J.D.,Chulalongkorn University
Computer Assisted Language Learning | Year: 2016

Learning spoken word forms is a vital part of second language learning, and CALL lends itself well to this training. Not enough is known, however, about how auditory variation across speech tokens may affect receptive word learning. To find out, 144 Thai university students with no knowledge of the Patani Malay language learned 24 foreign words in a CALL program for receptive vocabulary learning. Word meanings were presented in line drawings, and their spoken forms presented by either one or three Patani Malay speakers. Several other variables were included for control. Logistic regressions with and without adjustment by other factors suggested learners recognized somewhat fewer word meanings when trained with three Patani Malay speakers, especially under varied image conditions. This finding implies fragile initial auditory representations, and limited processing resources. The application of current results and their interpretation to CALL may be to limit sources of variation that would otherwise direct attention away from word forms. © 2016, 2015 Taylor & Francis.

Kanjanachuchai S.,Chulalongkorn University | Photongkam P.,111 University avenue
Crystal Growth and Design | Year: 2015

Langmuir evaporation of stressed InSb and InAs (111)B crystals is studied using low-energy electron microscopy. The stress induces plastic relaxation by dislocation generation, whereas the evaporation results in self-running In droplets. The coexistence of in situ generated dislocations and self-running droplets allows droplet-dislocation interaction to be studied with minimal perturbation from other effects. The droplets run toward a preferred direction but are guided along dislocation lines before setting themself free once they accumulate mass and sufficient momentum to climb the energetic barrier posed by surface steps. The guiding effects are explained by surface stress which drives the mobile liquid along the dislocation line. This mechanism provides a means to control the direction of the self-running or self-propelled droplets, adding another degree of freedom to the growth and design of droplet-assisted micro- and nanostructures, for example, via interfacial dislocation network formed during heteroepitaxy. © 2014 American Chemical Society.

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.

Kwok P.C.L.,University of Sydney | Tunsirikongkon A.,Chulalongkorn University | Glover W.,GSK Consumer Health | Chan H.-K.,University of Sydney
Pharmaceutical Research | Year: 2011

Purpose: To produce and examine the aerosol performance of protein nano-matrix particles with different surface roughness. Methods: Aqueous lysozyme solutions were poured into isopropanol during high-shear mixing to produce nanoparticles by precipitation. The size of the nanoparticles was varied by adjusting the precipitation conditions. The resultant suspensions were spray-dried to obtain micron-sized aggregates (nano-matrices). Smooth particles were made by spray-drying a lysozyme solution. The aggregate size distribution, surface roughness, and cohesion were evaluated. The aerosol performance was assessed by dispersing 10 mg of powder from a Rotahaler® at 60 L/min or an Aerolizer® at 100 L/min into a Next Generation Impactor, followed by chemical assay (n∈=∈3). Results: The median volume diameter and span of the nano-matrix particles were 1.0-1.2 μm and 1.5-1.6, respectively, which were comparable to those of the smooth particles. Surface roughness increased with the size of the primary nanoparticles. The nano-matrix particles were significantly less cohesive than the smooth particles. The fine particle fraction increased linearly with increasing surface roughness and decreasing cohesion. Conclusions: Nano-matrix particles with controlled surface architecture were successfully produced by spray-drying nanosuspensions. Aerosol performance was enhanced with increasing surface roughness due to the reduction in cohesion forces. © 2010 Springer Science+Business Media, LLC.

Roder C.,King Abdullah University of Science and Technology | Arif C.,King Abdullah University of Science and Technology | Bayer T.,King Abdullah University of Science and Technology | Aranda M.,King Abdullah University of Science and Technology | And 4 more authors.
ISME Journal | Year: 2014

Coral reefs are threatened throughout the world. A major factor contributing to their decline is outbreaks and propagation of coral diseases. Due to the complexity of coral-associated microbe communities, little is understood in terms of disease agents, hosts and vectors. It is known that compromised health in corals is correlated with shifts in bacterial assemblages colonizing coral mucus and tissue. However, general disease patterns remain, to a large extent, ambiguous as comparative studies over species, regions, or diseases are scarce. Here, we compare bacterial assemblages of samples from healthy (HH) colonies and such displaying signs of White Plague Disease (WPD) of two different coral species (Pavona duerdeni and Porites lutea) from the same reef in Koh Tao, Thailand, using 16S rRNA gene microarrays. In line with other studies, we found an increase of bacterial diversity in diseased (DD) corals, and a higher abundance of taxa from the families that include known coral pathogens (Alteromonadaceae, Rhodobacteraceae, Vibrionaceae). In our comparative framework analysis, we found differences in microbial assemblages between coral species and coral health states. Notably, patterns of bacterial community structures from HH and DD corals were maintained over species boundaries. Moreover, microbes that differentiated the two coral species did not overlap with microbes that were indicative of HH and DD corals. This suggests that while corals harbor distinct species-specific microbial assemblages, disease-specific bacterial abundance patterns exist that are maintained over coral species boundaries. © 2014 International Society for Microbial Ecology All rights reserved.

Jubsilp C.,Srinakharinwirot University | Takeichi T.,Toyohashi University of Technology | Rimdusit S.,Chulalongkorn University
Polymer Degradation and Stability | Year: 2011

A novel bisphenol-A-aniline type polybenzoxazine (PBA-a) modified with dianhydride was successfully prepared by reacting bisphenol-A-aniline based benzoxazine (BA-a) resin with 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) in 1-methyl-2-pyrrolidone (NMP) solvent. The miscible monomer mixture was easily transformed into transparent PBA-a/BTDA copolymers by thermal cure. Fourier-transform infrared spectroscopy reveals the formation of ester linkage which is a covalent interaction between hydroxyl group of the PBA-a and the carbonyl group in the dianhydride. The PBA-a/BTDA copolymers show only one glass transition temperature (Tg) with the value as high as 263 °C at BA-a:BTDA = 1.5:1 mol ratio. The value is remarkably higher than that of the unmodified PBA-a, i.e. 160 °C. In addition, the resulting PBA-a/BTDA copolymers display relatively high degradation temperature up to 364 °C and substantial enhancement in char yield with a value of up to 61% by weight. Moreover, flexibility of the PBA-a/BTDA copolymer samples is also significantly enhanced compared to the unmodified PBA-a. The obtained copolymer demonstrates high potential for those applications that require high thermal and mechanical properties with fire resistant characteristics. © 2011 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.

Saisinchai S.,Chulalongkorn University
Engineering Journal | Year: 2014

Recycling is an important activity in the minimization of waste that results from human activities. In the United States, 103.2 billion pounds of plastic are produced in 2011. Unfortunately, the majority of this plastic ends up in landfills where its decomposition process can take anywhere from 10 to 30 years. In this work, froth flotation was used to treat PVC (polyvinyl chloride) and PET (polyethylene terephthalate) mixtures. The parameters studied are fed mixtures component ratios, concentration of Calcium Lignosulfonate as wetting reagent and a number of cleaning flotation. The results show a yield of 100% pure PVC separated from PET.

Tompkins K.A.,Chulalongkorn University
Connective Tissue Research | Year: 2011

The past decade has seen rapid advancement in the dissection of the molecular events and players in the development and homeostasis of mineralized tissues, that is, teeth and bones. Much of this is due to research efforts toward the regeneration of these organs and also to develop treatments for pathologies of bone, especially osteoporosis. Of late, great interest has been focused on the Wnt family of proteins and their involvement in tooth and bone development and in the regulation of postnatal bone mass. The purpose of this review is to summarize these findings and to explore new areas of Wnt research such as Wntbone morphogenetic protein interactions and the exciting revelation of systemic serotonin being involved in bone mass regulation. © 2011 Informa Healthcare USA, Inc.

Siripatrawan U.,Chulalongkorn University | Makino Y.,University of Tokyo
International Journal of Food Microbiology | Year: 2015

This research aimed to develop a rapid, non-destructive, and accurate method based on hyperspectral imaging (HSI) for monitoring spoilage fungal growth on stored brown rice. Brown rice was inoculated with a non-pathogenic strain of Aspergillus oryzae and stored at 30. °C and 85% RH. Growth of A. oryzae on rice was monitored using viable colony counts, expressed as colony forming units per gram (CFU/g). The fungal development was observed using scanning electron microscopy. The HSI system was used to acquire reflectance images of the samples covering the visible and near-infrared (NIR) wavelength range of 400-1000. nm. Unsupervised self-organizing map (SOM) was used to visualize data classification of different levels of fungal infection. Partial least squares (PLS) regression was used to predict fungal growth on rice grains from the HSI reflectance spectra. The HSI spectral signals decreased with increasing colony counts, while conserving similar spectral pattern during the fungal growth. When integrated with SOM, the proposed HSI method could be used to classify rice samples with different levels of fungal infection without sample manipulation. Moreover, HSI was able to rapidly identify infected rice although the samples showed no symptoms of fungal infection. Based on PLS regression, the coefficient of determination was 0.97 and root mean square error of prediction was 0.39 log (CFU/g), demonstrating that the HSI technique was effective for prediction of fungal infection in rice grains. The ability of HSI to detect fungal infection at early stage would help to prevent contaminated rice grains from entering the food chain. This research provides scientific information on the rapid, non-destructive, and effective fungal detection system for rice grains. © 2015 Elsevier B.V.

Gumert M.D.,Nanyang Technological University | Malaivijitnond S.,Chulalongkorn University
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2013

Tool selection can affect the success of a tool-based feeding task, and thus toolusing animals should select appropriate tools when processing foods.We performed a field experiment on Piak Nam Yai Island in Laem Son National Park, Thailand, to test whether Burmese long-tailed macaques (Macaca fascicularis aurea) selected stone tools according to food type. We baited the island's shores with stone sets ('tool tests') in an effort to attract macaques to use stones presented in a quasi-experimental design. Tool tests were placed at 344 locations for 126 days over a 2 year period, with each set containing four stones of different mass (categories: X, 40-60 g; S, 90-100 g; M, 150-200 g; and L, 400-1000 g). Tool tests were checked when we could access them. The number of times each tool test was checked varied (1-32), for a total of 1950 checks. We also studied 375 non-experimental stone tools that were found at naturally occurring tool-use sites. Our data were not collected by direct observation, but by inspecting stones after use. We found an association between stone mass and food type. In the tool tests, we found S-stones were chosen most often for attached oysters, and L-stones were chosen most often for unattached foods. L-stones were almost always chosen for larger unattached foods (greater than 3 cm length), while for smaller unattached foods (less than or equal to 3 cm length) selection was less skewed to L-stones and more evenly distributed between the M- and L-stone categories. In the non-experimental study, we found that mass varied significantly across five food categories (range: 16-5166 g). We reveal more detail on macaque stone tool mass than previous studies, showing that macaques select differing stone masses across a variety of tool-processed foods. Our study is the first step in investigating the behavioural and cognitive mechanisms that macaques are using during tool selection. © 2013 The Author(s) Published by the Royal Society. 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.

Faungnawakij K.,National Science and Technology Development Agency | Viriya-Empikul N.,National Science and Technology Development Agency | Tanthapanichakoon W.,Chulalongkorn University
International Journal of Hydrogen Energy | Year: 2011

In the present study, a thermodynamic analysis of the autothermal reforming of dimethyl ether (DME) for the production of hydrogen was carried out. The results clearly indicated that the carbon formation behavior, the boundary conditions between coke-free and coking regions, and the equilibrium composition of the reformate were dependent on the steam/DME ratio, O2/DME ratio, temperature, and pressure of the system. For instance, carbon formation was effectively suppressed as the steam/DME ratio increased from 0 to 5, the O2/DME ratio increased from 0 to 3, or the temperature rose from 100 to 1000 °C. In contrast, carbon formation was enhanced as the pressure was increased from 0.5 to 10 atm. The boundary temperature of coke-free operation decreased with an increase in the steam/DME and O2/DME ratios. More specifically, at a steam/DME ratio of 3-5 and an O2/DME ratio of 0-3, the boundary temperature ranged from 50 to 280 °C (when CH4 formation was promoted) and 380 to 670 °C (when CH4 formation was suppressed), respectively. Furthermore, at elevated temperatures, H2 and CO formations were enhanced, and CH4 formation was inhibited. The addition of steam enhanced H2 production while reducing CO formation. On the contrary, an increase in the O2/DME ratio reduced H2 production while enhancing CO formation. Interestingly, the desired temperature for thermo-neutral condition, in which energy consumption was zero, can be achieved by correctly controlling the O2/DME and steam/DME ratios. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

Kanjanachuchai S.,Chulalongkorn University | Euaruksakul C.,111 University avenue
Crystal Growth and Design | Year: 2014

The nucleation and dynamics of multiple generations of In droplets formed from Langmuir evaporation of InP (001), (111)A, and (111)B surfaces are reported. In situ mirror electron microscopy reveals that the majority of first-generation, or mother, droplets break up immediately before they run from the nucleation sites, leaving behind daughter droplets and etch trails where more droplets emerge. These subsequent droplets grow with time and run once a critical size is reached. The breakup and running characteristics are explained in terms of crystallography, viscosity, chemical potential, and temperature and will likely affect the growth processes and designs of various droplet-catalyzed nanostructures and devices. © 2013 American Chemical Society.

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.

Kasivitamnuay J.,Chulalongkorn University
Engineering Journal | Year: 2016

Calculation of a stress intensity factor becomes more difficult when crack are subjected to a complicated stress distribution profile. A standard procedure called influence coefficients is inadequate because a stress profile may not be accurately represented by a polynomial function. This paper applies a piecewise linear approximation of stress profile and a weight function method to overcome that restriction. However, the typically adopted weight function, i.e. universal weight function, is replaced by a weight function, in which its form coincides with the analytical form. Although a new weight function consists of lesser number of terms, it is proved to be accurate when applies to a cracked-cylinder problem, e.g. internal part-through circumferential crack and internal fully circumferential crack under various complicated weld residual stress profiles. Using this simpler weight function and linearized approximation scheme led to a closed-form stress intensity factor solution, which is convenient for programming. © 2016, Chulalongkorn University 1. All right reserved.

Voraphani N.,University of Arizona | Voraphani N.,Chulalongkorn University | Stern D.A.,University of Arizona | Wright A.L.,University of Arizona | And 3 more authors.
American Journal of Respiratory and Critical Care Medicine | Year: 2014

Rationale: Risk of subsequent asthma-like symptoms after early-life lower respiratory illness (LRI) caused by respiratory syncytial virus (RSV) is increased during the first decade of childhood and diminished thereafter by adolescence. Objectives: To determine the relation of early-life RSV-LRI on adult asthma-like symptoms and its interactive role with adult smoking. Methods: A total of 1,246 nonselected infants were enrolled at birth and prospectively followed. Virologically confirmed RSV-LRIs were assessed during the first 3 years of life. At age 22, 24, 26, and 29 years, current asthma and smoking behavior were evaluated by questionnaire. Peak flow variability was assessed at age 26 and expressed as amplitude % mean. A longitudinal analysis was used to investigate the relation of RSV-LRI and active smoking to adult outcomes. Measurements and Main Results: Neither RSV-LRI nor active smoking were directly associated with increased current adult asthma or peak flow variability. However, there was a significant interaction between RSV-LRI and active smoking in relation to current asthma (P for interaction = 0.004) and peak flow variability (P for interaction = 0.04). Among subjects with early RSV-LRI, those who actively smoked were 1.7 times more likely to have current asthma (95% confidence interval, 1.2-2.3; P = 0.003) and had greater amplitude % mean (10.0% vs. 6.4%; P = 0.02) than nonsmokers. Among subjects without early RSV-LRI, there was no difference in asthma risk or peak flow variability between active smokers and nonsmokers. Conclusions: Smoking is associated with increased risk of having asthma in young adults who had RSV-LRI in early life but not among subjects without these illnesses. Copyright © 2014 by the American Thoracic Society.

Kasetsuwan N.,Chulalongkorn University
BMJ case reports | Year: 2013

A case of an immunocompetent 51-year-old healthy man with chronic recurrent disciform corneal oedema and hypertensive anterior uveitis in the right eye for 2 years was unresponsive to topical corticosteroid and systemic acyclovir. Diagnostic anterior chamber tapping was performed and viral DNA PCR was positive for both cytomegalovirus and herpes simplex virus. The patient was treated with both oral valganciclovir for 3 months and long-term oral acyclovir. His condition improved significantly after the treatment; intraocular pressure and anterior chamber inflammation were controlled and the remaining keratic precipitates in the cornea started to clear up.

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.

Boonserma P.,Chulalongkorn University | Visserb M.,Victoria University of Wellington
Journal of High Energy Physics | Year: 2011

The study of exact quasi-normal modes [QNMs], and their associated quasinormal frequencies [QNFs], has had a long and convoluted history - replete with many rediscoveries of previously known results. In this article we shall collect and survey a number of known analytic results, and develop several new analytic results - specifically we shall provide several new QNF results and estimates, in a form amenable for comparison with the extant literature. Apart from their intrinsic interest, these exact and approximate results serve as a backdrop and a consistency check on ongoing efforts to find general model-independent estimates for QNFs, and general model-independent bounds on transmission probabilities. Our calculations also provide yet another physics application of the Lambert W function. These ideas have relevance to fields as diverse as black hole physics, (where they are related to the damped oscillations of astrophysical black holes, to greybody factors for the Hawking radiation, and to more speculative state-counting models for the Bekenstein entropy), to quantum field theory (where they are related to Casimir energies in unbounded systems), through to condensed matter physics, (where one may literally be interested in an electron tunnelling through a physical barrier). © SISSA 2011.

Tangthieng C.,Chulalongkorn University
Applied Thermal Engineering | Year: 2011

One of the favorite forms of ice for consuming is tube ice, which is produced by a refrigeration unit referred to as an ice making tower. In order to redesign the tower for the energy-efficiency purpose, the aim of this paper is to numerically investigate the effect of tube diameter on the ice thickness, the cooling load, and the specific energy consumption. The mathematical model of the ice formation within the tube is developed by assuming unsteady and one-dimensional heat conduction. The governing equations are composed of the wall and the ice regions with the convective boundary condition and isothermal solidification at the interface. The governing system is transformed into a dimensionless form and numerically solved by the finite difference method. The numerical results are validated by comparing the ice thickness obtained from the numerical prediction and that obtained from the field measurement, resulting in qualitative agreement. The variations of ice thickness, cooling load, and specific energy consumption with time for four different tube diameters are presented. The result shows the location of the minimum specific energy consumption as a function of time. By comparing between different tube diameters, the value of the minimum specific energy consumption of a small diameter tube is lower than that of a large diameter one. On the other hand, the behavior of the specific energy consumption of a large diameter tube indicates the existence of a low specific energy consumption period of time beyond the minimum point. Therefore, by choosing a proper tube diameter, the minimum value of the average specific energy consumption over the entire production cycle is obtained, leading to higher energy efficiency. © 2010 Elsevier Ltd. All rights reserved.

Tanyanont W.,Chulalongkorn University | Vichit-Vadakan N.,Thammasat University
Southeast Asian Journal of Tropical Medicine and Public Health | Year: 2012

In Thailand, there is a growing concern regarding the possible effects of air pollution on the health of residents living near a petrochemical complex in Map Ta Phut Industrial Estate (MTPIE), Rayong Province, Thailand. We studied exposure to selected volatile organic compounds (VOCs) in Map Ta Phut and the association between residing near the petrochemical complex and respiratory ailments. We carried out a population-based cross-sectional study, utilizing health data regarding respiratory problems among adults collected as part of a Health Effects of Air Pollution study of residents living in Map Ta Phut Municipality, Thailand, using a standardized questionnaire. The distance from the subject's residence to the center of the MTPIE was mapped using a geographical information system (GIS). A total of 15,441 adults aged ≥ 13 years who lived in Map Ta Phut Municipality for at least 1 year were included in the study. Multiple logistic regression models were used to examine the relationship between the distance between the subject's residence and the MTPIE and the presence of the respiratory problems during the previous 12 months. A 5 km distance was chosen as the maximum study radius. Volatile organic compounds were observed higher concentrations at sites downwind from the MTPIE, and closer to the MTPIE. Study subjects who lived closer to the MTPIE reported an odor more frequently than subjects who lived farther from the MTPIE. Living closer to the MTPIE was associated with more acute respiratory problems, but not more chronic respiratory problems than living farther from the MTPIE. Adults aged ≥ 40 years were more likely to have respiratory symptoms and eye irritation than those aged < 40 years. Females were more likely to have dyspnea, wheezing and upper respiratory symptoms than males. Living near the MTPIE for more than 5 years was associated with an increased risk of wheezing and upper respiratory symptoms.

Kitisomprayoonkul W.,Chulalongkorn University
Journal of the Medical Association of Thailand = Chotmaihet thangphaet | Year: 2011

To translate the ID Pain scale into Thai and validate this scale. The 6-item ID Pain scale was translated into Thai. The final version was tested in 100 patients. Sensitivity, specificity, and predictive validity were calculated. Twenty-four patients were neuropathic, 49 were nociceptive and 27 were mixed pain. Forty-six patients have chronic pain. Seventy-five were female. Sensitivity and specificity for diagnosis of neuropathic pain were 83% and 80%. The predictive validity using area under the ROC curve of the neuropathic, mixed and nociceptive pain groups were 0.890 (95% CI 0.824-0.955), 0.587 (95% CI 0.464-0.709) and 0.147 (95% CI 0.071-0.224), respectively. The Thai ID Pain scale is brief convenient to complete and had good predictive validity for screening of neuropathic pain. Prediction validity of mixed pain is moderate and of nociceptive pain is low.

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.

Pluengphon P.,Chulalongkorn University
Journal of physics. Condensed matter : an Institute of Physics journal | Year: 2012

The effects of Na atoms on high pressure structural phase transitions of CuIn(0.5)Ga(0.5)Se(2) (CIGS) were studied by an ab initio method using density functional theory. At ambient pressure, CIGS is known to have chalcopyrite (I42d) structure. The high pressure phase transitions of CIGS were proposed to be the same as the order in the CuInSe(2) phase transitions which are I42d → Fm3m → Cmcm structures. By using the mixture atoms method, the Na concentration in CIGS was studied at 0.1, 1.0 and 6.25%. The positive mixing enthalpy of Na at In/Ga sites (Na(InGa)) is higher than that of Na at Cu sites (Na(Cu)). It confirmed previous studies that Na preferably substitutes on the Cu sites more than the (In, Ga) sites. From the energy-volume curves, we found that the effect of the Na substitutes is to reduce the hardness of CIGS under high pressure. The most significant effects occur at 6.25% Na. We also found that the electronic density of states of CIGS near the valence band maximum is increased noticeably in the chalcopyrite phase. The band gap is close in the cubic and orthorhombic phases. Also, the Na(Cu)-Se bond length in the chalcopyrite phase is significantly reduced at 6.25% Na, compared with the pure Cu-Se bond length. Consequently, the energy band gap in this phase is wider than in pure CIGS, and the gap increased at the rate of 31 meV GPa(-1) under pressure. The Na has a small effect on the transition pressure. The path of transformation from the cubic to orthorhombic phase was derived. The Cu-Se plane in the cubic phase displaced relatively parallel to the (In, Ga)-Se plane by 18% in order to transform to the Cmcm phase. The enthalpy barrier is 0.020 eV/atom, which is equivalent to a thermal energy of 248 K. We predicted that Fm3m and Cmcm can coexist in some pressure range.

Tammachote R.,Chulalongkorn University
Asian Biomedicine | Year: 2011

Osteoarthritis (OA), a degenerative joint disease, is the most common form of arthritis in the elderly. Problems arising from the condition are not only health, physical, and psychological, but also economical and social. OA is a complex disease causes by environmental factors (obesity, female gender, advancing age) and genetics. A strong genetic contribution to primary OA has been observed in several studies. Asian population is undoubtedly genetically different from European, whom most studies have been performed. This review systematically compares results of molecules involved with OA from studies performed on Asian and Caucasian populations. The clear differences between Asian and Caucasian populations may be from the sex- and ethnic-specific nature of the disease, as well as from the inclusion criteria of the studies. Global collaboration is highly significant in understanding genetic underlying OA. Knowledge gained from genetic study is important to the development of prevention and therapeutic intervention, and to identify individuals at risk of developing severe or progressive OA.

Pitakwatchara P.,Chulalongkorn University
Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME | Year: 2014

This paper addresses the task space impedance control of a robot driven through the multistage nonlinear flexible transmission. The proposed controller uses limited information of the angle and the current of the motors to regulate the end point compliance at the specified set point. In particular, motor angle is employed to estimate the stationary robot link angle and joint velocity in real time. They are then used to constitute the stationary force on the attempt to cancel the robot gravity force and to form the task space interacting force according to the desired impedance characteristics. Motor current is used to infer the transmitted torque to the robot. This torque is fed back to mitigate the effect of the motor inertia from deteriorating the desired impedance. Asymptotic stability of this controller with the flexible joint robot is guaranteed with additional damping. Passivity of the system is also investigated. Simulation and experiments of the proposed control scheme on a two degrees-of-freedom (DOF) cable-pulley driven flexible joint robot model are examined. Copyright © 2014 by ASME.

Chaiteerakij R.,Chulalongkorn University
American Journal of Gastroenterology | Year: 2014

OBJECTIVES:Current staging systems for perihilar cholangiocarcinoma (pCCA) are inadequate, as they are based on surgical pathology and therefore not relevant to unresectable patients. Clinical trials for potential targeted therapies for pCCA are hampered by the lack of an accurate, nonoperative staging system for predicting survival. We aimed at developing a clinical staging system for pCCA, which would be of prognostic relevance for all pCCA patients and help stratify patients for clinical trials.METHODS:Clinical information at the time of pCCA diagnosis of 413 patients seen at Mayo Clinic, Rochester, MN between 2002 and 2010 was retrospectively analyzed. A survival predictive model was developed using Cox proportional hazards analysis. The performance of the staging system was compared with the current AJCC/UICC (the American Joint Committee on Cancer/the Union for International Cancer Control) 7th tumor-node-metastasis (TNM) staging system.RESULTS:Eastern Cooperative Oncology Group (ECOG) status, tumor size and number, vascular encasement, lymph node and peritoneal metastasis and CA 19-9 level were grouped into a four-tier staging system. The median survivals of stages I, II, III, and IV patients were 48.6, 21.8, 8.6, and 2.8 months, with hazard ratios (95% confidence interval) of 1.0 (reference), 1.7 (1.1–2.6), 3.1 (2.0–4.7), and 8.7 (5.2–14.5), respectively (P<0.0001). This staging system had greater concordance statistics (standard error) than the TNM staging system (0.725 (0.018) vs. 0.614 (0.017)), indicating better performance in predicting survival.CONCLUSIONS:This staging system, based on nonoperative information at the time of pCCA diagnosis, has excellent discriminatory power to classify patients into four prognostic stages. It could be useful to clinicians and for the design of clinical trials.Am J Gastroenterol advance online publication, 11 November 2014; doi:10.1038/ajg.2014.327. © 2014 American College of Gastroenterology

Jintaridth P.,Mahidol University | Mutirangura A.,Chulalongkorn University
Physiological Genomics | Year: 2010

Interspersed repetitive sequences (IRSs) are a major contributor to genome size and may contribute to cellular functions. IRSs are subdivided according to size and functionally related structures into short interspersed elements, long interspersed elements (LINEs), DNA transposons, and LTR-retrotransposons. Many IRSs may produce RNA and regulate genes by a variety of mechanisms. The majority of DNA methylation occurs in IRSs and is believed to suppress IRS activities. Global hypomethylation, or the loss of genome-wide methylation, is a common epigenetic event not only in senescent cells but also in cancer cells. Loss of LINE-1 methylation has been characterized in many cancers. Here, we evaluated the methylation levels of peripheral blood mononuclear cells of LINE-1, Alu, and human endogenous retrovirus K (HERV-K) in 177 samples obtained from volunteers between 20 and 88 yr of age. Age was negatively associated with methylation levels of Alu (r = -0.452, P < 10-3) and HERV-K (r = -0.326, P < 10-3) but not LINE-1 (r = 0.145, P = 0.055). Loss of methylation of Alu occurred during ages 34-68 yr, and loss of methylation of HERV-K occurred during ages 40-63 yr and again during ages 64-83 yr. Interestingly, methylation of Alu and LINE-1 are directly associated, particularly at ages 49 yr and older (r = 0.49, P < 10-3). Therefore, only some types of IRSs lose methylation at certain ages. Moreover, Alu and HERV-K become hypomethylated differently. Finally, there may be several mechanisms of global methylation. However, not all of these mechanisms are age-dependent. This finding may lead to a better understanding of not only the biological causes and consequences of genome-wide hypomethylation but also the role of IRSs in the aging process. Copyright © 2010 the American Physiological Society.

Maitarad P.,University of Shanghai for Science and Technology | Han J.,University of Shanghai for Science and Technology | Zhang D.,University of Shanghai for Science and Technology | Shi L.,University of Shanghai for Science and Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2014

CeO2 nanorods impregnated with 2.5 atom % of NiO (NiO/CeO 2 nanorods) were successfully synthesized and examined as catalysts for the NH3-selective catalytic reduction (NH3-SCR) of nitric oxide (NO). The catalytic activity of NiO/CeO2 nanorods resulted in up to ∼90% NO conversion at 250 °C, which is superior to that of pure CeO2 nanorods or NiO nanoparticles. Subsequently, extensive studies of the NiO/CeO2-catalyzed reduction of NO were conducted using X-ray photoelectron spectroscopy, hydrogen temperature- programmed reduction, temperature-programmed desorption, and density functional theory periodic calculations. Compared to that of the pure CeO2 nanorods, the results demonstrated that the NiO/CeO2 nanorods resulted in (i) a higher concentration of Ce3+ chemical species, (ii) a larger amount of active Oα, (iii) lower temperature reducibility, (iv) a lower amount of energy required for oxygen vacancy distortion, and (v) a significant adsorption of and strong interaction between NO and NH3 molecules. Our findings therefore elucidated considerable details of the structural properties of the NiO/CeO2 nanorods that were decisive for achieving a highly efficient conversion of NO by the NH 3-SCR process at low temperatures. © 2014 American Chemical Society.

Craps B.,Vrije Universiteit Brussel | Craps B.,Ecole Normale Superieure de Paris | Evnin O.,Chulalongkorn University | Vanhoof J.,Vrije Universiteit Brussel
Journal of High Energy Physics | Year: 2014

We revisit the issues of non-linear AdS stability, its relation to growing (secular) terms in naïve perturbation theory around the AdS background, and the need and possible strategies for resumming such terms. To this end, we review a powerful and elegant resummation method, which is mathematically identical to the standard renormalization group treatment of ultraviolet divergences in perturbative quantum field theory. We apply this method to non-linear gravitational perturbation theory in the AdS background at first non-trivial order and display the detailed structure of the emerging renormalization flow equations. We prove, in particular, that a majority of secular terms (and the corresponding terms in the renormalization flow equations) that could be present on general grounds given the spectrum of frequencies of linear AdS perturbations, do not in fact arise. © The Authors.

Laosiripojana N.,King Mongkuts 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.

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.

Chalermpong S.,Chulalongkorn University
Transportation Research Record | Year: 2010

The impact of airport noise on home prices has received much attention in North America, where many hedonic price studies have been performed to examine the issue. In developing countries, however, extremely limited academic work on this topic has been conducted. The recent opening of Suvarnabhumi Airport in Bangkok, Thailand, presented a unique opportunity to address this research gap. In this paper, sales data of new homes near the airport that were sold between 2002 and 2008 are used to examine both the anticipatory effect and actual effects of airport noise on home prices. On the basis of this data set, hedonic price models are estimated and subjected to various diagnostic tests, including those for heteroscedasticity and spatial autocorrelation. The results show no anticipatory effects of airport noise on prices before the beginning of airport operations in 2006. More important, prices of new properties sold after 2006 are 19.15% lower in the most severely affected area and 8.55% lower in moderately affected areas. These estimates imply a noise depreciation index of 2.12% per decibel, which is in the high range of values found in the literature and implies that the potential benefits of a noise reduction program at Suvarnabhumi Airport might be substantial.

Zhao Y.,Chulalongkorn University
Journal of Optics (United Kingdom) | Year: 2015

We demonstrate highly directive and transversely confined emissions from hyperbolic metasurfaces (HMSs) to free-space. The generation of such beams is attributed to the narrow hyperbolic isofrequency contour, such that only propagating waves with their wavevectors near normal incidence can transmit through the medium. The directions of transmitted waves' Poynting vectors are altered by the medium and become parallel to the propagation direction, resulting in the generation of nondiffracting beams. We also suggest a realization of the proposed HMS using a layered silver-dielectric structure for optical wavelengths. © 2015 IOP Publishing 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.

Deachapunya C.,Srinakharinwirot University | Poonyachoti S.,Chulalongkorn University
Cellular Physiology and Biochemistry | Year: 2013

Background/Aim: Genistein, the most active isoflavone found primarily in soybeans, alters ion transport functions in intestinal and airway epithelia. The present study aims to investigate the acute effects and mechanisms of action of genistein in immortalized porcine endometrial epithelial cells. Methods: Ussing chamber technique was used for transepithelial electrical measurements. Results: Genistein increased short-circuit currents (Isc) which were inhibited by glibenclamide, NPPB, CFTRinh-172, DIDS or bumetanide, but not amiloride. In experiments with amphotericin B-permeabilized monolayers, genistein activated the apical Cl- current and barium-sensitive basolateral K+ current while inhibiting the apical K+ current. Genistein failed to increase the Isc in the presence of forskolin or IBMX, but did increase the Isc in UTP. Pretreatment with genistein also abolished the increase in the Isc when induced by forskolin, IBMX or UTP. However, Ca2+-chelating BAPTA-AM did not affect the genistein-induced increase in the Isc. The genistein-stimulated Isc was reduced by tyrosine kinase inhibitors, tyrphostin A23 or AG490. However, vanadate, a tyrosine phosphatase inhibitor, failed to inhibit the genistein response. Estrogen receptor antagonist ICI182,780 did not alter the genistein's action. Conclusion: The soy isoflavone, genistein, stimulates Cl- secretion in endometrial epithelial cells possibly via a direct activation of CFTR which appears to be modulated through a tyrosine kinase-dependent pathway. The present findings may be of benefit for the therapeutic application of genistein in the treatment of electrolyte transport disorders in the epithelia. © 2013 S. Karger AG, Basel.

Muttarak R.,International Institute For Applied Systems Analysis | Pothisiri W.,Chulalongkorn University
Ecology and Society | Year: 2013

In this paper we investigate how well residents of the Andaman coast in Phang Nga province, Thailand, are prepared for earthquakes and tsunami. It is hypothesized that formal education can promote disaster preparedness because education enhances individual cognitive and learning skills, as well as access to information. A survey was conducted of 557 households in the areas that received tsunami warnings following the Indian Ocean earthquakes on 11 April 2012. Interviews were carried out during the period of numerous aftershocks, which put residents in the region on high alert. The respondents were asked what emergency preparedness measures they had taken following the 11 April earthquakes. Using the partial proportional odds model, the paper investigates determinants of personal disaster preparedness measured as the number of preparedness actions taken. Controlling for village effects, we find that formal education, measured at the individual, household, and community levels, has a positive relationship with taking preparedness measures. For the survey group without past disaster experience, the education level of household members is positively related to disaster preparedness. The findings also show that disaster-related training is most effective for individuals with high educational attainment. Furthermore, living in a community with a higher proportion of women who have at least a secondary education increases the likelihood of disaster preparedness. In conclusion, we found that formal education can increase disaster preparedness and reduce vulnerability to natural hazards. © 2013 by the author(s).

Pauwels R.,Chulalongkorn University
Radiation Protection Dosimetry | Year: 2015

The widespread use of cone-beam CT (CBCT) in dentistry has led to increasing concern regarding justification and optimisation of CBCT exposures. When used as a substitute to multidetector CT (MDCT), CBCT can lead to significant dose reduction; however, low-dose protocols of current-generation MDCTs show that there is an overlap between CBCT and MDCT doses. More importantly, although the 3D information provided by CBCT can often lead to improved diagnosis and treatment compared with 2D radiographs, a routine or excessive use of CBCT would lead to a substantial increase of the collective patient dose. The potential use of CBCT for paediatric patients (e.g. developmental disorders, trauma and orthodontic treatment planning) further increases concern regarding its proper application. This paper provides an overview of justification and optimisation issues in dental and maxillofacial CBCT. The radiation dose in CBCT will be briefly reviewed. The European Commission's Evidence Based Guidelines prepared by the SEDENTEXCT Project Consortium will be summarised, and (in)appropriate use of CBCT will be illustrated for various dental applications. © The Author 2015.

Khanasuk Y.,Chulalongkorn University
Journal of the Medical Association of Thailand = Chotmaihet thangphaet | Year: 2012

To compare the efficacy of single 6-ml intraarticular injection between hylan G-F 20 and hyaluronic acid (HA) for knee osteoarthritis. Thirty-two patients with primary knee arthritis, who were randomly received single intraarticular injection of 6-ml hylan G-F 20 (Synvisc) or HA (Hyalgan), were prospectively evaluated for clinical outcomes at a minimum 26-week follow-up. The parameters, including visual analog scale (VAS) during walking, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and Short-Form 36 (SF-36) questionnaires, were evaluated at pre-injection, then at 1 week, 4 weeks, 8 weeks, 12 weeks and 26 weeks, post-injection. There were 15 patients in both groups who were available for final follow-up with no statistical differences in demographic data, VAS during walking, WOMAC score and SF-36 score at pre-injection. There was no adverse event related to viscosupplementation using in is better than of both agents. At 26-week follow-up, patients in both groups had significantly improved VAS during walking (p < 0.01), WOMAC score (p < 0.01) and SF-36 (p < 0.05) with no statistical differences between groups. However the cost of hylan G-F 20 was much more expensive than that of HA (534 USD vs. 252 USD). A single intraarticular injection of both hylan G-F 20 and HA for primary knee arthritis had no adverse event related to 6-ml volume. At 26-week follow-up of the present preliminary study, both groups had similarly improved clinical outcomes post-injection. Further study in larger population is required. As the cost of hylan G-F 20 was 2 times higher than HA, a single 6-ml intraarticular injection of HA (Hyalgan) provided better cost-effectiveness than hylan G-F 20 (Synvisc).

Siripatrawan U.,Chulalongkorn University | Makino Y.,University of Tokyo | Kawagoe Y.,University of Tokyo | Oshita S.,University of Tokyo
Talanta | Year: 2011

A rapid method based on hyperspectral imaging for detection of Escherichia coli contamination in fresh vegetable was developed. E. coli K12 was inoculated into spinach with different initial concentrations. Samples were analyzed using a colony count and a hyperspectroscopic technique. A hyperspectral camera of 400-1000 nm, with a spectral resolution of 5 nm was employed to acquire hyperspectral images of packaged spinach. Reflectance spectra were obtained from various positions on the sample surface and pretreated using Sawitzky-Golay. Chemometrics including principal component analysis (PCA) and artificial neural network (ANN) were then used to analyze the pre-processed data. The PCA was implemented to remove redundant information of the hyperspectral data. The ANN was trained using Bayesian regularization and was capable of correlating hyperspectral data with number of E. coli. Once trained, the ANN was also used to construct a prediction map of all pixel spectra of an image to display the number of E. coli in the sample. The prediction map allowed a rapid and easy interpretation of the hyperspectral data. The results suggested that incorporation of hyperspectral imaging with chemometrics provided a rapid and innovative approach for the detection of E. coli contamination in packaged fresh spinach. © 2011 Elsevier B.V. All rights reserved.

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.

Poomsawat S.,Mahidol University | Punyasingh J.,Mahidol University | Vejchapipat P.,Chulalongkorn University
Applied Immunohistochemistry and Molecular Morphology | Year: 2014

Survivin is an inhibitor of apoptosis protein that inhibits caspase 3 function. While cytoplasmic survivin suppresses apoptosis, nuclear survivin regulates cell division. Little is known about the subcellular localization of survivin in oral carcinogenesis. This study examined the subcellular distribution of these 2 proteins in oral squamous cell carcinoma (OSCC) and premalignant lesions including oral leukoplakia (OL) with and without dysplasia. Expression of survivin and caspase 3 were immunohistochemically analyzed in 114 samples including OSCC, OL with and without dysplasia, and normal oral mucosa (NM). Cytoplasmic and nuclear positive cells were counted separately. The results were presented as the frequency of positive cases. The positive expression rates of cytoplasmic and nuclear survivin in OSCC were significantly higher than in NM, OL with and without dysplasia. NM showed a low rate of cytoplasmic survivin expression compared to OL with and without dysplasia. The numbers of cytoplasmic and nuclear expression of caspase 3 in OSCC were significantly higher than that of NM, OL with and without dysplasia. In conclusion, the overexpression of cytoplasmic survivin in OSCC and premalignant lesions suggest that suppression of apoptosis by survivin occurs at early and late stages of oral carcinogenesis. The elevated expression of nuclear survivin and caspase 3 in OSCC indicate that at the late stage survivin increases cell proliferation whereas caspase 3 promotes apoptosis. © 2013 by Lippincott Williams and Wilkins.

Dhumrongvaraporn A.,Chulalongkorn University
Journal of cosmetic science | Year: 2013

Ultraviolet B (UVB)-mediated oxidative stress in keratinocytes has been accepted as an important factor contributing to skin damage. The present study revealed the kinetics of reactive oxygen species (ROS) production and identified the main specific ROS generated in human keratinocytes exposed to UVB. Keratinocytes were exposed to various doses of UVB, and intracellular ROS kinetics were evaluated by specific oxidant probes, namely, 2',7'-dichlorofluorescein diacetate, dihydroethidium, 10-acetyl-3,7-dihydroxyphenoxazine, and 3'-(p-hydroxyphenyl) fluorescein. Results revealed that UVB-irradiated cells exhibited significantly higher rate of ROS production in the early time period (0-2 h) compared to the nontreated control cells; however, the rate of ROS generation afterward (2-6 h) was similar to that of control cells. Specific ROS, including superoxide anion, hydrogen peroxide, and hydroxyl radical were enhanced in keratinocytes treated with UVB. Results regarding kinetics of specific ROS production revealed that superoxide anion and hydroxyl radical were the main ROS contributing to oxidative stress in the early phase (0-2 h) after UVB treatment in these cells. Further, this study showed the effect of known antioxidant, vitamin C, on ROS kinetics in UVB-exposed keratinocytes.

Sunasee R.,University of Alberta | Wattanaarsakit P.,Chulalongkorn University | Ahmed M.,University of Alberta | Lollmahomed F.B.,University of Alberta | Narain R.,University of Alberta
Bioconjugate Chemistry | Year: 2012

The development of polymeric systems with tailored properties as nonviral gene carriers continues to be a challenging and exciting field of research. We report here the synthesis and characterization of biodegradable, temperature- and pH-sensitive carbohydrate-based cationic nanogels as effective gene delivery carriers to Hep G2 cells. The temperature-sensitive property of the nanogels allows their facile complexation of DNA, while the pH-sensitive property allows the degradation of nanogels followed by the release of plasmid in the endosome. The nanogels are synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) technique and are evaluated for their DNA condensation efficacy. The gene delivery efficacies of these nanogels are subsequently studied and it is found that these cationic glyconanogels can serve as potent gene delivery vectors in hepatocytes. It is found that the gene delivery efficacies of this system are similar to that of branched poly(ethyleneimine), which is used as a positive control. Moreover, these nanogels show desirable properties for systemic applications including low toxicity and degradation in acidic environment. © 2012 American Chemical Society.

Chaithongwongwatthana S.,Chulalongkorn University
Cochrane database of systematic reviews (Online) | Year: 2012

Each year at least one million children worldwide die of pneumococcal infections. The development of bacterial resistance to antimicrobials adds to the difficulty of treatment of diseases and emphasizes the need for a preventive approach. Newborn vaccination schedules could substantially reduce the impact of pneumococcal disease in immunized children, but does not have an effect on the morbidity and mortality of infants less than three months of age. Pneumococcal vaccination during pregnancy may be a way of preventing pneumococcal disease during the first months of life before the pneumococcal vaccine administered to the infant starts to produce protection. To assess the effect of pneumococcal vaccination during pregnancy for preventing infant infection. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 December 2011) and reference lists of retrieved studies. Randomized controlled trials in pregnant women comparing pneumococcal vaccine with placebo or doing nothing or with another vaccine to prevent infant infections. Two review authors independently assessed trials for inclusion, methodological quality and extracted data using a data collection form. Data were checked for accuracy. We contacted study authors for additional information. Seven trials were included, but only five trials (579 participants) contributed data. There was no evidence that pneumococcal vaccination during pregnancy reduces the risk of neonatal infection (risk ratio (RR) 0.66; 95% confidence interval (CI) 0.30 to 1.46; two trials, 241 pregnancies). Although the data suggest an effect in reducing pneumococcal colonization in infants by 16 months of age (RR 0.33; 95% CI 0.11 to 0.98; one trial, 56 pregnancies), there was no evidence of this effect in infants at two to three months of age (RR 1.13; 95% CI 0.46 to 2.78; two trials, 146 pregnancies) or by six to seven months of age (RR 0.66; 95% CI 0.20 to 2.17; two trials, 144 pregnancies). No significant difference for tenderness at the injection site between women who received pneumococcal vaccine and those who received control vaccine (RR 3.20; 95% CI 0.32 to 31.54; two trials, 130 women). There is insufficient evidence to assess whether pneumococcal vaccination during pregnancy could reduce infant infections.

Warren J.K.,Chulalongkorn University
Earth-Science Reviews | Year: 2010

Throughout geological time, evaporite sediments form by solar-driven concentration of a surface or nearsurface brine. Large, thick and extensive deposits dominated by rock-salt (mega-halite) or anhydrite (mega-sulfate) deposits tend to be marine evaporites and can be associated with extensive deposits of potash salts (mega-potash). Ancient marine evaporite deposition required particular climatic, eustatic or tectonic juxtapositions that have occurred a number of times in the past and will so again in the future. Ancient marine evaporites typically have poorly developed Quaternary counterparts in scale, thickness, tectonics and hydrology. When mega-evaporite settings were active within appropriate arid climatic and hydrological settings then huge volumes of seawater were drawn into the subsealevel evaporitic depressions. These systems were typical of regions where the evaporation rates of ocean waters were at their maximum, and so were centred on the past latitudinal equivalents of today's horse latitudes. But, like today's nonmarine evaporites, the location of marine Phanerozoic evaporites in zones of appropriate adiabatic aridity and continentality extended well into the equatorial belts. Exploited deposits of borate, sodium carbonate (soda-ash) and sodium sulfate (salt-cake) salts, along with evaporitic sediments hosting lithium-rich brines require continental-meteoric not marine-fed hydrologies. Plots of the world's Phanerozoic and Neoproterozoic evaporite deposits, using a GIS base, shows that Quaternary evaporite deposits are poor counterparts to the greater part of the world's Phanerozoic evaporite deposits. They are only directly relevant to same-scale continental hydrologies of the past and, as such, are used in this paper to better understand what is needed to create beds rich in salt-cake, soda-ash, borate and lithium salts. These deposits tend be Neogene and mostly occur in suprasealevel hydrographically-isolated (endorheic) continental intermontane and desert margin settings that are subject to the pluvial-interpluvial oscillations of Neogene ice-house climates. When compared to ancient marine evaporites, today's marine-fed subsealevel deposits tend to be small sea-edge deposits, their distribution and extent is limited by the current ice-house driven eustasy and a lack of appropriate hydrographically isolated subsealevel tectonic depressions. For the past forty years, Quaternary continental lacustrine deposit models have been applied to the interpretation of ancient marine evaporite basins without recognition of the time-limited nature of this type of comparison. Ancient mega-evaporite deposits (platform and/or basinwide deposits) require conditions of epeiric seaways (greenhouse climate) and/or continent-continent proximity. Basinwide evaporite deposition is facilitated by continent-continent proximity at the plate tectonic scale (Late stage E through stage B in the Wilson cycle). This creates an isostatic response where, in the appropriate arid climate belt, large portions of the collision suture belt or the incipient opening rift can be subsealevel, hydrographically isolated (a marine evaporite drawdown basin) and yet fed seawater by a combination of ongoing seepage and occasional marine overflow. Basinwide evaporite deposits can be classified by their tectonic setting into: convergent (collision basin), divergent (rift basin; prerift, synrift and postrift) and intracratonic settings. Ancient platform evaporites can be a subset of basinwide deposits, especially in intracratonic sag basins, or part of a widespread epeiric marine platform fill. In the latter case they tend to form mega-sulfate deposits and are associated with hydrographically isolated marine fed saltern and evaporitic mudflat systems in a greenhouse climatic setting. The lower amplitude 4 and 5th order marine eustatic cycles and the greater magnitude of marine freeboard during greenhouse climatic periods encourages deposition of marine platform mega-sulfates. Platform mega-evaporites in intracratonic settings are typically combinations of halite and sulfate beds. © 2009 Elsevier B.V. All rights reserved.

Tiarawut S.,Chulalongkorn University
Wireless Personal Communications | Year: 2013

The recent extraordinary growth of smart phones and tablets gives rise to the mobile application market. It opens up opportunity for new type of entrepreneurs to tap into the fast-growing mobile application market, bypassing the incumbent operators and requiring minimal capitals. Therefore, focus should be given to promoting these mobile entrepreneurs in order to change Thailand from a 'consumer' to a 'producer' of ICT technologies. This paper reviews recent trends on mobile technology in the mobile ecosystem and mobile application market. It then identifies emerging opportunity for business entrepreneurs. Furthermore, the measures being implemented by Mobile Technology for Thailand (MT2), an alliance from government, business and education sectors for promotion of mobile application industry, are explained. Specifically, it consists of human resource development, entrepreneur incubation and marketing support. It is expected that by focusing on inspiring a new generation of mobile application developers into entrepreneurship, incubating them into successful business and promoting their mobile app to the world market, Thailand could become a regional hub for mobile application industry in the near future. © 2013 Springer Science+Business Media New York.

Anderson G.,CRC | Maes M.,Deakin University | Maes M.,Chulalongkorn University
CNS and Neurological Disorders - Drug Targets | Year: 2014

In many psychiatric, neurodegenerative and systemic inflammatory disorders circadian melatonin is decreased whilst melatonin enzymes and melatonin receptors are genetic susceptibility factors. Treatment with melatonin is useful in a diverse range of medical conditions, including bipolar disorder, Alzheimer's disease, depression and fibromyalgia. Decreased melatonin effects are classically attributed to lost pineal production. However, melatonin, along with its immediate precursor N-acetylserotonin (NAS), is produced by many, if not all, mitochondrial containing cells, including immune cells and central glia. Here we review the data on local melatonin and NAS production and propose that astrocyte melatonin and NAS efflux is crucial to local central inflammation regulation at the glia-neuronal interface. Melatonin and NAS provide antioxidant and anti-inflammatory effects, as well as increasing mitochondrial oxidative phosphorylation and functioning. Consequently, their decreased production at sites of local inflammation is proposed to underlie melatonin's genetic association with a diverse range of medical conditions. Similarly the benefits of serotonin boosting medications, including antidepressants, across a wide range of conditions are partly mediated by increasing serotonin availability for astrocytic local NAS and melatonin production. Such a conceptualization incorporates a plethora of data across different disorders, especially the commonalities in oxidative and nitrosative stress, anti-oxidants, tryptophan catabolites and mitochondrial dysregulation evident in a diverse array of medical conditions. Glia melatonin and NAS regulation are important treatment targets in psychiatric disorders, neurodegenerative disorders and glioma. © 2014 Bentham Science Publishers.

Petchwattana N.,Srinakharinwirot University | Covavisaruch S.,Chulalongkorn University
Journal of Bionic Engineering | Year: 2013

This research aims to develop Wood Plastic Composites (WPCs) from rice hull and poly(vinyl chloride) (PVC). The influences of the rice hull particle size and content on the mechanical properties and the visual appearance of the WPC decking board were investigated. The experimental results revealed that the impact strength tended to decrease with increasing rice hull content. The composites with larger particle sizes exhibited higher impact strength. Under tensile and flexure load, higher rice hull content induced greater modulus and ultimate strength when the rice hull was applied at less than 60 phr. Beyond this concentration, the modulus and the strength dropped due to the formation of rice hull agglomerates. The smaller particles of the milled rice hull, the greater tendency there was for them to act as a pigment to form a darker shade close that of the rice hull on the composite decking board. The larger particle sizes were 106 μm and beyond simply embedded in the white PVC matrix. © 2013 Jilin University.

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.

Singh A.,Indian Institute of Technology Ropar | Raj T.,Indian Institute of Technology Ropar | Aree T.,Chulalongkorn University | Singh N.,Indian Institute of Technology Ropar
Inorganic Chemistry | Year: 2013

Biginelli-based molecules (1-3) have been synthesized and developed as a new class of fluorescent organic nanoparticle-based chemosensors. Chemosensor 2 has shown excellent selectivity and sensitivity for detection of Hg2+ in an aqueous medium. It can detect Hg2+ up to 1 nM, and the resultant 2Hg2+ complex can detect Cl- ions (micromolar level) in an aqueous medium. © 2013 American Chemical Society.

Gumert M.D.,Nanyang Technological University | Hoong L.K.,Nanyang Technological University | Malaivijitnond S.,Chulalongkorn University
American Journal of Primatology | Year: 2011

We investigated sex differences in how Burmese long-tailed macaques (Macaca fascicularis aurea) used stone tools to open shelled food items along the shores of two islands in Laemson National Park, Thailand. Over a 2-week period in December 2009, we collected scan and focal samples on macaques when they were visible along the shores and mangroves. We found females used stones more often while feeding and used smaller tools than males. Females also processed sessile oysters more than males, whereas males processed unattached foods more than females. It was unclear which sex was overall more proficient at stone tool use, but males did perform significantly better at opening unattached food items with large pounding stones. Females also struck food items more times during tool-use bouts and at a faster rate, but no significant difference was found in average tool-use bout duration. Males processed foods slightly faster within a tool-use bout, but we were unable to detect a significant difference in the rate of food processing while foraging with tools. In summary females chipped open sessile oysters with an axing technique more than males, while males used larger stones to pound open unattached shelled food more often than females. Despite using pounding more than females, males also regularly utilized the axing technique on sessile oysters. Our results are the first assessment of sex differences in macaque stone tool use, providing a basis for comparison with tool use in other primates, and to nonfunctional forms of stone use in other macaques. © 2011 Wiley Periodicals, Inc.

Karndumri P.,Chulalongkorn University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

We construct supersymmetric Janus solutions using four-dimensional N=3 gauged supergravity with SO(3)×SU(3) gauge group. The N=3 supersymmetric AdS4 vacuum with unbroken SO(3)×SU(3), identified with the compactification of eleven-dimensional supergravity on AdS4×N010, provides a gravity dual of supersymmetric N=3 Chern-Simons-Matter theory in three dimensions with SU(3) flavor symmetry. The Janus solutions accordingly describe supersymmetric conformal interfaces within this Chern-Simons-Matter theory via the AdS/CFT holography. We find two classes of Janus solutions preserving respectively (2,1) and (0,1) supersymmetry on the (1+1)-dimensional conformal defects. The solution with (2,1) supersymmetry preserves SO(2)×SO(2)×SO(2) SO(3)×SU(3) symmetry while the (0,1) supersymmetric solution is invariant under a larger SO(2)×SU(2)×SO(2) symmetry. © 2016 American Physical Society.

Chontanawat J.,King Mongkuts University of Technology Thonburi | Wiboonchutikula P.,Chulalongkorn University | Buddhivanich A.,King Mongkuts 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.

The biological underpinnings to the etiology and course of neurodegeneration in Parkinson's disease are an area of extensive research that has yet to produce an early biological marker or disease-slowing or preventative treatment. Recent conceptualizations of Parkinson's disease have integrated immuno-inflammation and oxidative and nitrosative stress occurring in depression, somatization and peripheral inflammation into the course of Parkinson's disease. We review the data showing the importance of immuno-inflammatory processes and oxidative and nitrosative stress in such classically conceived 'comorbidities', suggesting that lifetime, prodromal and concurrent depression and somatization may be intricately involved in the etiology and course of Parkinson's disease, rather than psychiatric comorbidities. This produces a longer term developmental perspective of Parkinson's disease, which incorporates tryptophan catabolites (TRYCATs), lipid peroxidation, sirtuins, cyclic adenosine monophosphate, aryl hydrocarbon receptor, and circadian genes. This integrates wider bodies of data pertaining to neuronal loss in Parkinson's disease, emphasizing how these interact with susceptibility genes to drive changes in mitochondria, blood-brain barrier permeability and intercellular signalling. We review this data here in the context of neurodegeneration in Parkinson's disease and to the future directions indicated for slowing disease progression. © 2013 Springer Science+Business Media.

Malliga S.,Chulalongkorn University
Journal of Environmental Management and Tourism | Year: 2014

The objectives of this study are to estimate the income and price elasticities of tourist demand in Thailand. A linear expenditure system is employed in this paper. It is assumed that a consumer maximizes his or her utility subject to a budget constraint. A data set of consumer price indices (CPI) of six commodities and the expenditure of tourists from selected countries for 1985 – 2012 are used. This paper focuses on the expenditure of tourists from Thailand’s major tourism markets including Laos People’s Democratic Republic, the People’s Republic of China, Malaysia, Japan, Korea, the Russian Federation, India, Australia, the United Kingdom and the United States of America. The data are obtained from the Tourism Authority of Thailand, the Department of Tourism, the Ministry of Commerce, and the National Statistical Office. It is revealed that the income and prices of six commodities affect the expenditure of tourists from various countries differently. International tourists from different countries have different preferences for commodities. Pricing strategy may respond to the low price elasticity and may increase the tourism revenues of inbound tourism in Thailand. The study provides some interesting findings that may help to provide a better understanding of the behavior of international tourists. © 2014 ASERS Publishing House. All rights reserved.

Viriyasitavat W.,Chulalongkorn University | Martin A.,University of Oxford
IEEE Communications Surveys and Tutorials | Year: 2012

Abstract With the fast-growing Internet technology, several service-based interactions are prevalent and appear in several forms such as e-commerce, content provider, Virtual Organizations, Peer-to-Peer, Web Service, Grids, Cloud Computing, and individual interactions. This demands for an effective mechanism to establish trust among participants in a high-level abstract way, capturing relevant factors ranging on Service Level Agreement, security policies, requirements, regulations, constraints, Quality of Service, reputation, and recommendation. Trust is platform-independent and flexible to be seamlessly integrated into heterogeneous domains and interoperate with different security solutions in distributed environments. Establishing trust in a service workflow leads to the willingness of services to participate. Coordinating service workflows without trust consideration may pose higher risks, possibly results in poor performance, additional vulnerabilities, or failures. Although trust in service workflows and relevant contexts has been studied for a past decade, the standard development is still immature. Nowadays, trust approaches to service workflows comprise a large area of research where one can hardly classify into a comprehensive survey. This survey examines and explores the role of trust in service workflows and their contexts from a wide variety of literatures. Various mechanisms, architecture, techniques, standards, and frameworks are explained along the way with discussions. Working trust definition and classification are newly provided and supported with examples. © 2012 IEEE.

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

Ruangwises S.,Chulalongkorn University | Ruangwises N.,Mahidol University
Journal of Food Protection | Year: 2011

Concentrations of total and inorganic arsenic were determined in 120 samples of eight marine animals collected from the Gulf of Thailand between March and May 2008. Two species with the highest annual catch from each of four marine animal groups were analyzed: fish (Indo-Pacific mackerel and goldstripe sardine), bivalves (green mussel and blood cockle), cephalopods (pharaoh cuttlefish and Indian squid), and crustaceans (banana prawn and swimming crab). Concentrations of inorganic arsenic based on wet weight ranged from 0.012 μg/g in Indian squids to 0.603 μg/g in blood cockles. Average percentages of inorganic arsenic with respect to total arsenic ranged from 1.2% in banana prawns to 7.3% in blood cockles. Blood cockles also exhibited the highest levels of total arsenic (5.26 ± 2.01 μg/g) and inorganic arsenic (0.352 ± 0.148 μg/g). The levels of inorganic arsenic in the study samples were much lower than the Thai regulatory limit of 2 μg/g (wet wt) and hence are safe for human consumption. Copyright © International Association for Food Protection.

Berk M.,Deakin University | Berk M.,University of Melbourne | Galecki P.,Medical University of Lodz | Galecki P.,University of Lodz | And 2 more authors.
Molecular Neurobiology | Year: 2014

The World Health Organization classifies myalgic encephalomyelitis/chronic fatigue syndrome (ME/cfs) as a nervous system disease. Together with other diseases under the G93 heading, ME/cfs shares a triad of abnormalities involving elevated oxidative and nitrosative stress (O&NS), activation of immuno-inflammatory pathways, and mitochondrial dysfunctions with depleted levels of adenosine triphosphate (ATP) synthesis. There is also abundant evidence that many patients with ME/cfs (up to around 60 %) may suffer from autoimmune responses. A wide range of reported abnormalities in ME/cfs are highly pertinent to the generation of autoimmunity. Here we review the potential sources of autoimmunity which are observed in people with ME/cfs. The increased levels of pro-inflammatory cytokines, e.g., interleukin-1 and tumor necrosis factor-α, and increased levels of nuclear factor-κB predispose to an autoimmune environment. Many cytokine abnormalities conspire to produce a predominance of effector B cells and autoreactive T cells. The common observation of reduced natural killer cell function in ME/cfs is a source of disrupted homeostasis and prolonged effector T cell survival. B cells may be pathogenic by playing a role in autoimmunity independent of their ability to produce antibodies. The chronic or recurrent viral infections seen in many patients with ME/cfs can induce autoimmunity by mechanisms involving molecular mimicry and bystander activation. Increased bacterial translocation, as observed in ME/cfs, is known to induce chronic inflammation and autoimmunity. Low ATP production and mitochondrial dysfunction is a source of autoimmunity by inhibiting apoptosis and stimulating necrotic cell death. Self-epitopes may be damaged by exposure to prolonged O&NS, altering their immunogenic profile and become a target for the host's immune system. Nitric oxide may induce many faces of autoimmunity stemming from elevated mitochondrial membrane hyperpolarization and blockade of the methionine cycle with subsequent hypomethylation of DNA. Here we also outline options for treatment involving rituximab and endotherapia. © 2013 Springer Science+Business Media.

Zhang X.,Rochester College | Harmsen W.S.,Rochester College | Mettler T.A.,Rochester College | Kim W.R.,Rochester College | And 5 more authors.
Hepatology | Year: 2014

The risks and benefits of metformin use in patients with cirrhosis with diabetes are debated. Although data on a protective effect of metformin against liver cancer development have been reported, metformin is frequently discontinued once cirrhosis is diagnosed because of concerns about an increased risk of adverse effects of metformin in patients with liver impairment. This study investigated whether continuation of metformin after cirrhosis diagnosis improves survival of patients with diabetes. Diabetic patients diagnosed with cirrhosis between 2000 and 2010 who were on metformin at the time of cirrhosis diagnosis were identified (n = 250). Data were retrospectively abstracted from the medical record. Survival of patients who continued versus discontinued metformin after cirrhosis diagnosis was compared using the log-rank test. Hazard ratio (HR) and 95% confidence interval (CI) were calculated using Cox's proportional hazards analysis. Overall, 172 patients continued metformin whereas 78 discontinued metformin. Patients who continued metformin had a significantly longer median survival than those who discontinued metformin (11.8 vs. 5.6 years overall, P < 0.0001; 11.8 vs. 6.0 years for Child A patients, P = 0.006; and 7.7 vs. 3.5 years for Child B/C patients, P = 0.04, respectively). After adjusting for other variables, continuation of metformin remained an independent predictor of better survival, with an HR of 0.43 (95% CI: 0.24-0.78; P = 0.005). No patients developed metformin-associated lactic acidosis during follow-up. Conclusion: Continuation of metformin after cirrhosis diagnosis reduced the risk of death by 57%. Metformin should therefore be continued in diabetic patients with cirrhosis if there is no specific contraindication. © 2014 by the American Association for the Study of Liver Diseases.

Jeandron D.D.,University of Southern California | Sahakitrungruang T.,Chulalongkorn University
Hormone Research in Paediatrics | Year: 2012

Background: 3β-hydroxysteroid dehydrogenase (3βHSD) type 2 (encoded by HSD3B2) is expressed in the adrenals and gonads. HSD3B2 mutations cause the rare form of congenital adrenal hyperplasia '3βHSD deficiency'. In its classic form, affected individuals have salt wasting early in infancy and may have ambiguous genitalia in both sexes. The presence of peripheral type 1 3βHSD often complicates the hormonal diagnosis of this disorder, in that very high 17α-hydroxypregnenolone levels can be converted extra-adrenally to 17α-hydroxyprogesterone (17OHP). Patient and Methods: A 46,XX female newborn with no signs of virilization was referred for evaluation of positive 17OHP newborn screening, and developed a salt-wasting crisis at 13 days of age. The confirmatory test revealing highly elevated 17OHP suggested a 21-hydroxylase deficiency, but sequencing of the CYP21A2 gene was not consistent. Further family history suggested a 3βHSD deficiency. The HSD3B2 gene was then sequenced. Results: The patient was homozygous for the novel nonsense mutation Q334X in the HSD3B2 gene, inherited from both parents. Conclusions: We report a novel mutation of the HSD3B2 gene, Q334X, responsible for a classic 3βHSD deficiency. The clinical and hormonal phenotypes can be complicated in this disorder, and this supports the benefits of 17OHP newborn screening to detect various forms of congenital adrenal hyperplasia. Copyright © 2012 S. Karger AG, Basel.

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.

Ahmed M.,University of Alberta | Wattanaarsakit P.,Chulalongkorn University | Narain R.,University of Alberta
European Polymer Journal | Year: 2013

The significant progress made in understanding the role of carbohydrates and carbohydrates based therapeutics at molecular level has highlighted the importance of carbohydrate bioconjugates in the field of biology, chemistry and therapeutics. The glycosylation of biomolecules is a nature-inspired approach, to impart structural and functional properties to the biomolecules. The availability of facile techniques to synthesize well-defined glycopolymers of varying molecular weights, compositions and shape and their facile conjugation with biomolecules of interest have helped researchers in understanding many aspects of their biological functions at the molecular level. This review focuses on the development of glycopolymer-bioconjugates and provides a comprehensive overview of the present bioconjugation tools for their synthesis. The glycosylation of biomolecules is achieved by either pre or post-polymerization modification approaches. The review highlights the potential of living radical polymerization for the facile synthesis of glycopolymer bioconjugates using both pre and post-polymerization bioconjugation approaches, and without disrupting the native structure and functions of the biological molecules. Non-covalent carbohydrate-carbohydrate and carbohydrate-protein interactions play a significant role in many biological and pathological events. The non-covalent interactions of synthetic glycopolymers with biomolecules are also discussed in this review. © 2013 Elsevier Ltd. All rights reserved.

Zhao Y.,Chulalongkorn University
Electronics Letters | Year: 2016

In this Letter, a dual-wideband microstrip antenna for long-term evolution (LTE) applications is proposed. The antenna is fed by a single port, and designed to operate at 800-960 MHz and 1700-2700 MHz simultaneously. The antenna has a return loss of less than -14 dB for both frequency bands, and gain of 3-4 dBi at the lower band and 6-8 dBi at the higher band. The proposed antenna may find its applications in second generation (2G), 3G, 4G LTE and WiFi systems. © The Institution of Engineering and Technology 2016.

Ongwandee M.,Mahasarakham University | Chavalparit O.,Chulalongkorn University
Journal of Environmental Sciences | Year: 2010

Measurements and monitoring of volatile organic compounds (VOCs) have been conducted in the metropolitan Bangkok. However, in-vehicle levels of VOCs are still lacking. This study investigated VOCs concentrations in four public transportation modes in Bangkok, Thailand during two rush hour periods (7:00-9:00 a.m. and 4:00-7:00 p.m.). The four modes included an air-conditioned bus (A/C bus), non-air-conditioned bus (non-A/C bus), electric sky train, and a passenger boat traveling along the canal. Comparison among three important bus routes was also studied. In-vehicle air samples were collected using charcoal sorbent tubes and then analyzed by a gas chromatography-mass spectrometer. Results showed that the transportation modes significantly influenced the abundance of in-vehicle benzene, toluene, ethylbenzene, and m,p-xylene (BTEX). Median concentrations of BTEX were 11.7, 103, 11.7, and 42.8 μg/m3 in A/C bus; 37.1, 174, 14.7, and 55.4 μg/m3 in non-A/C bus; 2.0, 36.9, 0.5, and 0.5 μg/m3 in sky train; and 3.1, 58.5, 0.5, and 6.2 μg/m3 in boat, respectively. Wilcoxon rank sum test indicated that toluene and m,p-xylene in the sky trains were statistically lower than that in the other three modes at a p-value of 0.05. There were statistical differences in TEX concentrations among the bus routes in the non-A/C buses. In addition, the benzene to toluene ratios implied that tail-pipe emissions were important contributor to the abundance of in-vehicle VOCs. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Evnin O.,Chulalongkorn University | Evnin O.,Vrije Universiteit Brussel | Krishnan C.,Indian Institute of Science
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Recent investigations have revealed powerful selection rules for resonant energy transfer between modes of nonlinear perturbations in global anti-de Sitter (AdS) space-time. It is likely that these selection rules are due to the highly symmetric nature of the underlying AdS background, though the precise relation has remained unclear. In this article, we demonstrate that the equation satisfied by the scalar field mode functions in AdSd+1 has a hidden SU(d) symmetry, and explicitly specify the multiplets of this SU(d) symmetry furnished by the mode functions. We also comment on the role this structure might play in explaining the selection rules. © 2015 American Physical Society.

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.

Maqbool T.,University of Michigan | Srikiratiwong P.,University of Michigan | Srikiratiwong P.,Chulalongkorn University | Fogler H.S.,University of Michigan
Energy and Fuels | Year: 2011

Asphaltene precipitation is a challenging problem for the petroleum industry. Changes in pressure, temperature, and composition are key factors that influence asphaltene stability in crude oils. We have previously shown that the time required to precipitate asphaltenes can actually vary from a few minutes to several months, depending on the precipitant concentration used and that no single concentration can be identified as the critical precipitant concentration for asphaltene precipitation. Both upstream and downstream processes involve temperature variations, which can cause the precipitation of asphaltenes and can lead to deposition and fouling problems during the production, transportation, and processing of crude oils. In the present work, we extend the findings of the previous research to incorporate the effect of temperature on the precipitation kinetics of asphaltenes. The effect of temperature on asphaltene stability can be complex and various competing effects can be identified. We demonstrate that at higher temperatures the precipitation onset time for asphaltenes is shorter and their solubility is higher. We also present a hypothesis to explain these results and demonstrate that the viscosity difference resulting from a change in temperature is the key parameter in the aggregation of asphaltenes and controls the onset time for precipitation. We also consider the effect of expansion of hydrocarbons, oxidation of crude oil, and the loss of light hydrocarbons due to evaporation, all of which are possible when temperature is increased. This research provides a unified approach to understand the variety of factors that change as a result of temperature variation and evaluates their individual contributions to changes in asphaltene precipitation kinetics and their solubility. © 2011 American Chemical Society.

Noipa T.,Materials Chemistry Research Unit | Tuntulani T.,Chulalongkorn University | Ngeontae W.,Materials Chemistry Research Unit
Talanta | Year: 2013

A new fluorescence sensor for detection of cyanide ions (CN-) in aqueous media based on the recovered fluorescence of cysteamine capped CdS quantum dots [Cys-CdS QDs]-Cu2+ system was proposed. The fluorescence intensity of Cys-CdS QDs was quenched by Cu2+ due to the binding of Cu2+ to cysteamine on the surface of the QDs. The degree of fluorescence quenching was proportional to the concentration of Cu2+. However, in the presence of CN-, the fluorescence intensity of Cys-CdS QDs was found to be efficiently recovered. Experimental results showed that the pH of the buffer solution and the concentration of Cu2+ affected the fluorescence intensity upon adding CN-. Under the optimal condition, the recovered fluorescence intensity was linearly proportional to the increasing CN- concentration in the range 2.5-20 μM. The limit of detection and the limit of quantification were found to be 1.13 μM and 3.23 μM, respectively. In addition, among the tested ions, only CN- could turn on the fluorescence intensity suggesting that the [Cys-CdS QDs]-Cu2+ system was a highly selective sensor for CN -. Moreover, this proposed sensor was demonstrated to detect CN - in drinking water with satisfactory results. © 2012 Elsevier B.V. All rights reserved.

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.

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.

Wontanatawatot W.,Chulalongkorn University
Journal of the Medical Association of Thailand = Chotmaihet thangphaet | Year: 2011

Peritoneal membrane changes over time in long-term peritoneal dialysis (PD) patients lead to dialysis failure and increased morbidity as well as mortality. Bio-incompatable PD solution, peritonitis, and uremia are hypothesized in causing membrane damage. Fibrous organization and angiogenesis of peritoneum are crucial morphological alterations which can diminish the efficacy of exchange and cause ultrafiltration failure. Pathophysiologic mechanisms of membrane damage have been extensively studied to innovate therapeutic strategies. One of the potential mechanisms is a presence of local renin-angiotensin-aldosterone system (RAAS) by which injured peritoneal mesothelial cell-derived angiotensin-II (AII) causes activations in TGF-beta, VEGF expression, and epithelial-to-mesenchymal transition (EMT) which contributes to extracellular matrix accumulation and neoangiogenesis in submesothelial tissues. Clinical evidence of RAAS blockade on human peritoneal membrane remains under investigation and is still inconclusive but relevant data seem to demonstrate its benefit on membrane preservation. Longitudinal effect of RAAS blockade on membrane structural, functional, and clinical relationships and strategies to use angiotensin converting enzyme inhibitor (ACEI), angiotensin II receptor blocker (ARB), aldosterone antagonist, and direct renin inhibitor are an interesting field to be explored.

Asavapanumas C.,Chulalongkorn University
The Journal of prosthetic dentistry | Year: 2013

As a result of natural tooth anatomy or gingival recession, anterior teeth are more likely to present increased abutment finish line curvature. The purpose of this study was to investigate the influence of the curvature of the finish line on the marginal gap widths of ceramic copings. An ivorine maxillary central incisor was prepared for 3 different abutment finish line curvatures (1, 3, and 5 mm). Thirty-six copings were fabricated for each of these curvatures by using Cercon, IPS e.max, and Lava systems. The marginal gap width was measured by using a stereomicroscope, and the data were subsequently analyzed by means of a 2-way ANOVA and a 1-way ANOVA (α=.05). A significantly higher mean marginal gap width was found for the 5-mm curvature group (Cercon, 76.59 ±23.01 μm; IPS e.max, 106.44 ±18.48 μm; Lava, 128.34 ±20.79 μm) than for both the 3-mm curvature group (Cercon, 60.18 ±9.74 μm; IPS e.max, 81.79 ±16.20 μm; Lava, 99.19 ±15.32 μm) and the 1-mm curvature group (Cercon, 38.3 ±6.85 μm; IPS e.max, 52.22 ±10.66 μm; Lava, 69.99 ±6.77 μm). The greater the finish line curvature, the wider the marginal gap widths for the 3 ceramic systems. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Vongpradhip S.,Chulalongkorn University
Proceedings of the 8th International Conference on Computer Science and Education, ICCSE 2013 | Year: 2013

In this paper a novel approach to multiplex data in QR Code is presented. This technique can increase the amount of data, as the original information, in QR Code as well as keeping secret information. The original data for encoding is divided into smaller parts, each part will form QR Code pattern in its standard form. Each pattern is encoded or multiplexed and represented each module in QR Code with black and white special symbols. At the receiving end, this QR Code with special symbols (that was multiplexed) is decoded to give back the number of QR Code patterns that was multiplexed. These QR Code pattern can be read by the general QR Code reader and the data can be concatenated back to form its original information. © 2013 IEEE.

Chaiteerakij R.,Rochester College | Chaiteerakij R.,Chulalongkorn University | Addissie B.D.,Rochester College | Roberts L.R.,Rochester College
Clinical Gastroenterology and Hepatology | Year: 2015

New biomarkers of hepatocellular carcinoma (HCC) have been identified using advanced genomic, proteomic, and metabolomics technologies. These are being developed not only for use in diagnosis of HCC, but also in prediction of patient and treatment outcomes and individualization of therapy. Some HCC biomarkers are currently used in surveillance to detect early stage HCCs and reduce mortality. Further studies are needed to determine whether the recently identified HCC biomarkers can be used in clinical practice; most are only in phase 1 or 2 studies. The diagnostic and predictive abilities of biomarkers are limited by the heterogeneous nature of HCCs; there is no perfect single biomarker of this tumor. To improve performance, combinations of biomarkers (panels), or combinations of biomarkers and clinical parameters or laboratory test results, might be required. We describe recently discovered biomarkers of HCC and discuss challenges to their development and application. © 2015 AGA Institute.

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.

Chanprateep S.,Chulalongkorn University
Journal of Bioscience and Bioengineering | Year: 2010

The microbial polyesters known as polyhydroxyalkanoates (PHAs) positively impact global climate change scenarios by reducing the amount of non-degradable plastic used. A wide variety of different monomer compositions of PHAs has been described, as well as their future prospects for applications where high biodegradability or biocompatibility is required. PHAs can be produced from renewable raw materials and are degraded naturally by microorganisms that enable carbon dioxide and organic compound recycling in the ecosystem, providing a buffer to climate change. This review summarizes recent research on PHAs and addresses the opportunities as well as challenges for their place in the global market. © 2010 The Society for Biotechnology, Japan.

Craps B.,Vrije Universiteit Brussel | Evnin O.,Vrije Universiteit Brussel | Evnin O.,Chulalongkorn University | Vanhoof J.,Vrije Universiteit Brussel
Journal of High Energy Physics | Year: 2015

Abstract: Important insights into the dynamics of spherically symmetric AdS-scalar field perturbations can be obtained by considering a simplified time-averaged theory accurately describing perturbations of amplitude ε on time-scales of order 1/ε2. The coefficients of the time-averaged equations are complicated expressions in terms of the AdS scalar field mode functions, which are in turn related to the Jacobi polynomials. We analyze the behavior of these coefficients for high frequency modes. The resulting asymptotics can be useful for understanding the properties of the finite-time singularity in solutions of the time-averaged theory recently reported in the literature. We highlight, in particular, the gauge dependence of this asymptotics, with respect to the two most commonly used gauges. The harsher growth of the coefficients at large frequencies in higher-dimensional AdS suggests strengthening of turbulent instabilities in higher dimensions. In the course of our derivations, we arrive at recursive relations for the coefficients of the time-averaged theory that are likely to be useful for evaluating them more efficiently in numerical simulations. © 2015, The Author(s).

Karndumri P.,Chulalongkorn University
Journal of High Energy Physics | Year: 2015

Abstract: We study AdS5 × Σ2 and AdS4 × Σ3 solutions of N = 2, SO(4) gauged supergravity in seven dimensions with Σ2,3 being S2,3 or H2,3. The SO(4) gauged supergravity is obtained from coupling three vector multiplets to the pure N = 2, SU(2) gauged supergravity. With a topological mass term for the 3-form field, the SO(4) ∼ SU(2) × SU(2) gauged supergravity admits two supersymmetric AdS7 critical points, with SO(4) and SO(3) symmetries, provided that the two SU(2) gauge couplings are different. These vacua correspond to N = (1, 0) superconformal field theories (SCFTs) in six dimensions. In the case of Σ2, we find a class of AdS5 × S2 and AdS5 × H2 solutions preserving eight supercharges and SO(2) × SO(2) symmetry, but only AdS5 × H2 solutions exist for SO(2) symmetry. These should correspond to some N = 1 four-dimensional SCFTs. We also give RG flow solutions from the N = (1, 0) SCFTs in six dimensions to these four-dimensional fixed points including a two-step flow from the SO(4) N = (1, 0) SCFT to the SO(3) N = (1, 0) SCFT that eventually flows to the N = 1 SCFT in four dimensions. For AdS4 × Σ3, we find a class of AdS4 × S3 and AdS4 × H3 solutions with four supercharges, corresponding to N =1 SCFTs in three dimensions. When the two SU(2) gauge couplings are equal, only AdS4 × H3 are possible. The uplifted solutions for equal SU(2) gauge couplings to eleven dimensions are also given. © 2015, The Author(s).

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

Abstract: Sterile neutrinos with a mass of a few keV can serve as cosmological warm dark matter. We study the production of keV sterile neutrinos in the early universe from the decay of a frozen-in scalar. Previous studies focused on heavy frozen-in scalars with masses above the Higgs mass leading to a hot spectrum for sterile neutrinos with masses below 8 − 10 keV. Motivated by the recent hints for an X-ray line at 3.55 keV, we extend the analysis to lighter frozen-in scalars, which allow for a cooler spectrum. Below the electroweak phase transition, several qualitatively new channels start contributing. The most important ones are annihilation into electroweak vector bosons, particularly W -bosons as well as Higgs decay into pairs of frozen-in scalars when kinematically allowed. © 2015, The Author(s).

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).

Eab C.H.,Chulalongkorn University | Lim S.C.,Braddell View
Physica A: Statistical Mechanics and its Applications | Year: 2010

Fractional generalized Langevin equation with external force is used to model single-file diffusion. It is found that for external force that varies with power law the solution for such a fractional Langevin equation gives the correct short and long time behavior for the mean square displacement of single-file diffusion when appropriate choice of parameters associated with fractional generalized Langevin equation are used. By considering some special cases of the fractional generalized Langevin equation, a new class of closed analytic expressions for the mean square displacement of single-file diffusion can be obtained. The effective Fokker-Planck equation associated with single-file diffusion is briefly considered. © 2010 Elsevier B.V. All rights reserved.

Chaithongwongwatthana S.,Chulalongkorn University
Journal of the Medical Association of Thailand | Year: 2015

Seroconcordant and serodiscordant couples living with HIV should be counseled and informed regarding reproductive health issues, including conceptive options. Assisted conception, sperm washing, timed intercourse, and vaginal self-insemination are options to be considered by HIV-affected couples who wish to conceive with a lowered risk of viral transmission. Preexposure prophylaxis may be an adjunctive method to reduce the risk, particularly among serodiscordant couples. © 2015, Medical Association of Thailand. All rights reserved.

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.

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.

The Mn- and Co-substituted polyoxotungstates [MPW11O39]5- (M = Mn or Co) supported on MCM-41 or into interlayer of Mg3Al-layered double hydroxide show catalytic activity for the solvent-free oxidation of benzyl alcohol and cyclohexane with H2O2. © 2016 Mendeleev Communications. Published by ELSEVIER B.V.

Jacquet A.,Chulalongkorn University
International Archives of Allergy and Immunology | Year: 2011

House dust mite (HDM) represents one of the most common sources of aeroallergens worldwide and more than 50% of allergic patients are sensitized to these allergenic molecules. HDM allergy research in the past has been mainly focused on adaptive, mite allergen-dependent immune responses. In recent years it has become clear that, although the allergen-specific CD4+ Th2 cellsorchestrate HDM allergic response,the innate immune system also plays a critical role in HDM-induced allergy pathogenesis. This review will summarize insights into diverse determinants that contribute to the HDM allergenicity through the activation of innate immunity. In addition to the capacity of mite allergens to directly activate mainly skin keratinocytes and airway epithelial cells, innate pattern recognition receptor ligands derived from HDM carriers are also involved in the development of allergic response by HDM. © 2010 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 o