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Kuala Selangor, Malaysia

Universiti Putra Malaysia , or UPM, is recognised by the independent government assessments as one of Malaysia's leading research Universities. Founded in 1931 as the School of Agriculture, the University today combines impressive modern facilities and a dynamic approach to teaching and research with its proud heritage of quality services and achievements. UPM main campus located in central Peninsular Malaysia, close to the capital city, Kuala Lumpur and next to Malaysia’s administrative capital city, Putrajaya. It was formerly known as Universiti Pertanian Malaysia or Agricultural University of Malaysia. UPM is a research university offering undergraduate and postgraduate courses with a research focus on agricultural science and its related fields. It was ranked as the joint 376th best university in the world in 2014 by Quacquarelli Symonds. Wikipedia.

Isahak W.N.R.W.,National University of Malaysia | Hisham M.W.M.,National University of Malaysia | Yarmo M.A.,National University of Malaysia | Yun Hin T.-Y.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2012

The paper provides an updated review on thermal conversion of biomass for the production of liquid products referred as bio-oil. This technology is described focusing on the characterization of feedstock, reactor design, products formation and upgrading. For feedstock characterization is covered in terms of several pretreatment methods. The reactor designs are illustrated number of design ranging from fixed bed to circulating fluidized bed. The properties of bio-oil composition have caused increasingly extensive research to be undertaken to address properties that need modification and this area is reviewed in terms of physical, catalytic and chemical upgrading. The mechanism of the products formation is also illustrated by several chemical routes. Reactor parameters such as heating rate, temperature of pyrolysis, catalysts etc are reviewed. © 2012 Elsevier Ltd.

Arai T.,University of Tokyo | Arai T.,University Putra Malaysia | Chino N.,University of Tokyo
Journal of Fish Biology | Year: 2012

The freshwater eels of the genus Anguilla, which are catadromous, migrate between freshwater growth habitats and offshore spawning areas. A number of recent studies, however, found examples of the temperate species Anguilla anguilla, Anguilla rostrata, Anguilla japonica, Anguilla australis and Anguilla dieffenbachii that have never migrated into fresh water, spending their entire life history in the ocean. Furthermore, those studies found an intermediate type between marine and freshwater residents, which appear to frequently move between different environments during their growth phase. The discovery of marine and brackish-water residents Anguilla spp. suggests that they do not all have to be catadromous, and it calls into question the generalized classification of diadromous fishes. There has been little available information, however, concerning migration in tropical Anguilla spp. Anguilla marmorata, shows three fluctuation patterns: (1) continuous residence in fresh water, (2) continuous residence in brackish water and (3) residence in fresh water after recruitment, while returning to brackish water. Such migratory patterns were found in other tropical species, Anguilla bicolor bicolor and Anguilla bicolor pacifica. In A. b. bicolor collected in a coastal lagoon of Indonesia, two further patterns of habitat use were found: (1) constantly living in either brackish water or sea water with no freshwater life and (2) habitat shift from fresh water to brackish water or sea water. The wide range of environmental habitat use indicates that migratory behaviour of tropical Anguilla spp. is facultative among fresh, brackish and marine waters during their growth phases after recruitment to the coastal areas. Further, the migratory behaviours of tropical Anguilla spp. appear to differ in each habitat in response to inter and intra-specific competition. The results suggest that tropical Anguilla spp. have a flexible pattern of migration, with an ability to adapt to various habitats and salinities. The ability of anguillids to reside in environments of various salinities would be a common feature between tropical and temperate species without a latitudinal cline. Thus, the migration of Anguilla spp. into fresh water is clearly not an obligatory behaviour. This evidence of geographical variability among Anguilla spp. suggests that habitat use is determined by environmental conditions in each site. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Baqiah H.,National University of Malaysia | Ibrahim N.B.,National University of Malaysia | Abdi M.H.,National University of Malaysia | Halim S.A.,University Putra Malaysia
Journal of Alloys and Compounds | Year: 2013

High transparent In2O3 and Cr-doped In 2O3 (In2-xCrxO3) nanocrystalline thin films were prepared using a simple sol-gel method followed by a spin coating technique. The effect of Cr concentration on the structural, microstructure, electrical and optical properties of In2-xCr xO3 were systematically investigated using X-ray diffractometer (XRD), atomic force microscopy (AFM), UV-vis spectroscopy, field emission scanning electron microscopy (FESEM) and Hall effect technique. The films have good crystallization with preferred orientation to (222) direction. The lattice parameters, a, of In2O3 system increased at lowest dopants (x = 0.025) and decreased as the dopant was further increased. The optical transmittance of films increased up to 98% for x = 0.05 and decreased for further Cr concentrations. From AFM measurement the films nanocrystals morphology was depending on Cr concentrations. The band gap was around 3.76 eV for pure and with x 6 0.075 however it increased. The effect of Cr concentrations on conducting mechanisms of In2O3 film has been investigated from 80 to 300 K using thermal activated conduction band and hopping models. The films, at x = 0.0-0.075, have typical semiconductor behaviour. Three different conducting mechanisms have been estimated. All thermal activation energies and conduction hopping parameters have been determined and analysed in details. © 2013 Elsevier B.V. All rights reserved.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Singh M.,Monash University | Forde G.M.,Monash University | Danquah M.K.,Monash University
Renewable and Sustainable Energy Reviews | Year: 2010

Microalgae biotechnology has recently emerged into the lime light owing to numerous consumer products that can be harnessed from microalgae. Product portfolio stretches from straightforward biomass production for food and animal feed to valuable products extracted from microalgal biomass, including triglycerides which can be converted into biodiesel. For most of these applications, the production process is moderately economically viable and the market is developing. Considering the enormous biodiversity of microalgae and recent developments in genetic and metabolic engineering, this group of organisms represents one of the most promising sources for new products and applications. With the development of detailed culture and screening techniques, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. This review article discusses the technology and production platforms for development and creation of different valuable consumer products from microalgal biomass. © 2009 Elsevier Ltd. All rights reserved.

Edith O.,University Putra Malaysia
Pertanika Journal of Science and Technology | Year: 2012

Biodiesel is an attractive renewable energy source, which is suitable as a substitute to the non-renewable petroleum diesel. However, it is plagued by its relatively bad cold flow behaviour. In this review, the factors affecting the cold flow of biodiesel, vis-à-vis the contradicting requirement of good cold flow and good ignition properties, are discussed. Fuel filter plugging, and crystallization of biodiesel are considered, together with the cold flow properties such as Pour Point (PP), Cloud Point (CP), Cold Filter Plugging Point (CFPP) and Low Temperature Filterability Test (LTFT). In addition, various methods used to improve the cold flow of biodiesel are also presented, with a special emphasis laid on the effects of these methods in reducing the Cloud Point. Strategies to improve cold flow, and yet maintaining the good ignition quality of biodiesel, are also proposed. As far as the cold flow of biodiesel is concerned, desirable attributes of its esters are short, unsaturated and branched carbon chains. However, these desirable attributes present opposing properties in terms of ignition quality and oxidation stability. This is because esters with short, unsaturated and branched carbon chains possess very good cold flow but poor ignition quality and oxidation stability. The target is therefore to produce biodiesel with good cold flow, sufficient ignition quality, and good oxidation stability. This target proves to be quite difficult and is a major problem in biodiesel research. New frontiers in this research might be the design of the new cold flow improvers that is similar to those used in the petroleum diesel but is tailored for biodiesel. Genetic modifications of the existing feedstock are also desirable but the food uses of this particular feedstock should always be taken into consideration. © Universiti Putra Malaysia Press.

Chew B.H.,University Putra Malaysia | Khoo E.M.,University of Malaya | Chia Y.C.,University of Malaya
Asia-Pacific Journal of Public Health | Year: 2015

Introduction. The purpose of this study is to examine the prevalence of social support and its association with glycemic control in patients with type 2 diabetes mellitus (T2D) in an urban primary care center within an academic institution. Social support is important in the management of chronic diseases. However, its association with glycemic control has been controversial. Methods. This was part of a study examining religiosity in T2D patients. Nonsmoking patients with T2D for at least 3 years and aged 30 years and above were recruited. Social support was measured using The Social Support Survey-Medical Outcomes Study (SS), a self-administered questionnaire; the scores range from 19 to 95, and a high score indicates better social support. Glycemic control was measured using the 3 most recent glycosylated hemoglobin (HbA1c) levels within the past 3 years. Results. A total of 175 participants completed the SS survey (response rate 79.0%). The mean age was 62.7 (standard deviation [SD] = 10.8) years, and the mean duration of diabetes was 11.74 (SD = 6.7) years. The mean HbA1c level was 8.15 (SD = 1.44). The mean SS score was 68.1. The prevalence of high and low social support were 29.7% and 24.0 %, respectively. A significant correlation was found between SS score and number of social supporters (n = 167). No significant correlation was found between the self-reported number of social supporters or the SS score and the mean HbA1c level. Conclusions. Social support was not associated with glycemic control in adult patients with T2D in this primary care setting. © 2011 APJPH.

The aim of this study was to optimize the different process parameters including pressure, temperature, and polymer concentration, to produce fine small spherical particles with a narrow particle size distribution using a supercritical antisolvent method for drug encapsulation. The interaction between different process parameters was also investigated. The optimized process parameters resulted in production of nanoencapsulated paracetamol in L-polylactide with a mean diameter of approximately 300 nm at 120 bar, 30°C, and a polymer concentration of 16 ppm. Thermogravimetric analysis illustrated the thermal characteristics of the nanoparticles. The high electrical charge on the surface of the nanoparticles caused the particles to repel each other, with the high negative zeta potential preventing flocculation. Our results illustrate the effect of different process parameters on particle size and morphology, and validate results obtained via RSM statistical software. Furthermore, the in vitro drug-release profile is consistent with a Korsmeyer-Peppas kinetic model.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Nanoscale Research Letters | Year: 2011

An analysis is carried out to study the steady two-dimensional stagnation-point flow of a nanofluid over a stretching/shrinking sheet in its own plane. The stretching/shrinking velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point. The similarity equations are solved numerically for three types of nanoparticles, namely copper, alumina, and titania in the water-based fluid with Prandtl number Pr = 6.2. The skin friction coefficient, Nusselt number, and the velocity and temperature profiles are presented graphically and discussed. Effects of the solid volume fraction ø on the fluid flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. © 2011 Bachok et al; licensee Springer.

Ahadzadeh A.S.,University Putra Malaysia | Pahlevan Sharif S.,Taylors University | Ong F.S.,University of Nottingham Malaysia Campus | Khong K.W.,Taylors University
Journal of Medical Internet Research | Year: 2015

Background: Today, people use the Internet to satisfy health-related information and communication needs. In Malaysia, Internet use for health management has become increasingly significant due to the increase in the incidence of chronic diseases, in particular among urban women and their desire to stay healthy. Past studies adopted the Technology Acceptance Model (TAM) and Health Belief Model (HBM) independently to explain Internet use for health-related purposes. Although both the TAM and HBM have their own merits, independently they lack the ability to explain the cognition and the related mechanism in which individuals use the Internet for health purposes. Objective: This study aimed to examine the influence of perceived health risk and health consciousness on health-related Internet use based on the HBM. Drawing on the TAM, it also tested the mediating effects of perceived usefulness of the Internet for health information and attitude toward Internet use for health purposes for the relationship between health-related factors, namely perceived health risk and health consciousness on health-related Internet use. Methods: Data obtained for the current study were collected using purposive sampling; the sample consisted of women in Malaysia who had Internet access. The partial least squares structural equation modeling method was used to test the research hypotheses developed. Results: Perceived health risk (β=.135, t1999=2.676) and health consciousness (β=.447, t1999=9.168) had a positive influence on health-related Internet use. Moreover, perceived usefulness of the Internet and attitude toward Internet use for health-related purposes partially mediated the influence of health consciousness on health-related Internet use (β=.025, t1999=3.234), whereas the effect of perceived health risk on health-related Internet use was fully mediated by perceived usefulness of the Internet and attitude (β=.029, t1999=3.609). These results suggest the central role of perceived usefulness of the Internet and attitude toward Internet use for health purposes for women who were health conscious and who perceived their health to be at risk. Conclusions: The integrated model proposed and tested in this study shows that the HBM, when combined with the TAM, is able to predict Internet use for health purposes. For women who subjectively evaluate their health as vulnerable to diseases and are concerned about their health, cognition beliefs in and positive affective feelings about the Internet come into play in determining the use of health-related Internet use. Furthermore, this study shows that engaging in health-related Internet use is a proactive behavior rather than a reactive behavior, suggesting that TAM dimensions have a significant mediating role in Internet health management. ©Ashraf Sadat Ahadzadeh, Saeed Pahlevan Sharif, Fon Sim Ong, Kok Wei Khong.

Selvarajah G.T.,University Utrecht | Selvarajah G.T.,University Putra Malaysia | Kirpensteijn J.,University Utrecht
Veterinary Journal | Year: 2010

Canine osteosarcoma (OS) is an aggressive tumour that accounts for approximately 90% of primary bone tumours in the dog. Although the standard treatments (including limb amputation/sparing, chemotherapy and palliative radiotherapy) have significantly increased survival rates, almost 90% of animals will eventually develop predominantly pulmonary metastases. Despite advances in various therapies, prognosis remains poor, with median survival times ranging from 3. months to 1. year and <20% of dogs survive for >2. years following diagnosis.Various clinical and epidemiological markers have facilitated decision-making with respect to therapy but no single molecular biomarker has been shown to enhance prediction of disease progression. The publication of the canine genome in 2005 raised the possibility of increasing understanding of the genetic mechanisms underpinning canine OS. This review explores the use of biomarkers within the multi-disciplinary management of dogs with OS, and highlights the few known, potential prognostic/predictive molecular markers including their potential value as 'bridging biomarkers' for human OS. Although high-throughput profiling of canine OS remains in its infancy, research within the next decade using leading-edge screening technologies has the potential to identify biomarkers that may enhance diagnostic and prognostic accuracy and result in more effective, individually tailored, treatment and management protocols for affected dogs. © 2010 Elsevier Ltd.

Naji A.,Islamic Azad University at Tehran | Ismail A.,University Putra Malaysia
Aquatic Ecosystem Health and Management | Year: 2012

This investigation was conducted to determine metals contamination from anthropogenic sources in sediments of Klang Estuary. Surface sediments from Klang Estuary were analyzed for metals (Cd, Zn, Ni, Cu, Pb and Fe), organic carbon and particles sizes. Quality assessment of sediments was evaluated using modified degree of contamination (mCd) and pollution load index (PLI). A comparison was also made with sediment quality guideline values. The present study showed that highest concentrations of metals were found in stations with high anthropogenic discharge. The mCd and PLI suggested that degree of metals contamination in surface sediments could be classified as "low to moderate degree of contamination." With the rapid economic development and urbanization around the Klang Estuary, ongoing monitoring studies on heavy metals contamination should focus on contaminant sources within the estuary. © 2012 Copyright Taylor and Francis Group, LLC.

Zamli K.Z.,Universiti Sains Malaysia | Klaib M.F.J.,Universiti Sains Malaysia | Younis M.I.,Universiti Sains Malaysia | Isa N.A.M.,Universiti Sains Malaysia | Abdullah R.,University Putra Malaysia
Information Sciences | Year: 2011

To ensure an acceptable level of quality and reliability of a typical software product, it is desirable to test every possible combination of input data under various configurations. However, due to the combinatorial explosion problem, exhaustive testing is practically impossible. Resource constraints, cost factors, and strict time-to-market deadlines are some of the main factors that inhibit such a consideration. Earlier research has suggested that a sampling strategy (i.e., one that is based on a t-way parameter interaction) can be effective. As a result, many helpful t-way sampling strategies have been developed and can be found in the literature. Several advances have been achieved in the last 15 years, which have, in particular, served to facilitate the test planning process by systematically minimizing the test size required (based on certain t-way parameter interactions). Despite this significant progress, the integration and automation of strategies (from planning process to execution) are still lacking. Additionally, strategizing to sample (and construct) a minimum test set from the exhaustive test space is an NP-complete problem; that is, it is often unlikely that an efficient strategy exists that could regularly generate an optimal test set. Motivated by these challenges, this paper discusses the design, implementation, and validation of an efficient strategy for t-way testing, the GTWay strategy. The main contribution of GTWay is the integration of t-way test data generation with automated (concurrent) execution as part of its tool implementation. Unlike most previous methods, GTWay addresses the generation of test data for a high coverage strength (t > 6). © 2011 Elsevier Inc. All rights reserved.

Karimi-Googhari S.H.,Shahid Bahonar University of Kerman | Lee T.S.,University Putra Malaysia
International Journal of Soft Computing | Year: 2011

Accurate prediction of reservoir inflows is crucial for optimizing the operations of managing water resources. With emerging new data driven modeling approaches, methods based on neuro-fuzzy are becoming established in academic and practical applications. This study investigates the ability of Adaptive Neuro-Fuzzy Inference System (ANFIS) method to improve the accuracy of daily reservoir inflow forecasting. The subtractive clustering method is used to find the best number of fuzzy rules. A comparison is made between the ANFIS model and the Artificial Neural Network (ANN) model. A wide range of statistics measures are used to evaluate the performance of the models. Based on comparisons, it was revealed that the ANFIS technique could not improve the accuracy of estimations in a small tropical catchment and the ANN performed better, especially in capturing peak inflows. © Medwell Journals, 2011.

Silver nanoparticles (AgNPs) of a small size were successfully synthesized using the wet chemical reduction method into the lamellar space layer of montmorillonite/chitosan (MMT/Cts) as an organomodified mineral solid support in the absence of any heat treatment. AgNO3, MMT, Cts, and NaBH4 were used as the silver precursor, the solid support, the natural polymeric stabilizer, and the chemical reduction agent, respectively. MMT was suspended in aqueous AgNO3/Cts solution. The interlamellar space limits were changed (d-spacing = 1.24-1.54 nm); therefore, AgNPs formed on the interlayer and external surface of MMT/Cts with d-average = 6.28-9.84 nm diameter. Characterizations were done using different methods, ie, ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. Silver/montmorillonite/chitosan bionanocomposite (Ag/MMT/Cts BNC) systems were examined. The antibacterial activity of AgNPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria, ie, Escherichia coli, E. coli O157:H7, and Pseudomonas aeruginosa by the disc diffusion method using Mueller Hinton agar at different sizes of AgNPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biological research and biomedical applications, including surgical devices and drug delivery vehicles.

Rubber tapping processes posed potential risk of various health problems among rubber workers. It ranges from simple musculoskeletal aches to more serious and complicated structural damage to bone, muscles, tendons and nerves of musculoskeletal system. These health problems might be linked directly to the arduous demands of farm labor. A cross-sectional study was conducted to determine the prevalence of neck pain (NP) and musculoskeletal symptoms (MSS) and its association with personal characteristics, physical workloads and psychosocial factors among rubber workers. Stratified random sampling method was adopted and a total of 419 rubber workers in FELDA's scheme Malaysia participated in this study. Data was collected through face to face interview using modified Standardized Nordic Questionnaire (SNQ) and Job Content Questionnaire (JCQ). The results revealed the prevalence of NP was 59.9% and weak correlation with age (?= -0.184, p= 0.001) and a positive weak correlation with working hours per day (?= 0.099, p= 0.043) significantly. All physical workloads (neck flexion or rotation, awkward postures, repetitive motion and static postures) had significant weak to moderate positive correlation with NP (p<0.05). Job insecurity was found to have weak and positive correlation with NP (p<0.05). Binary logistic regression analysis showed risk factors for NP were decreased with age (OR= 3.92, 95% CI 1.61 - 9.58, p=0.003), increase in neck flexion or rotation (OR= 9.52, 95% CI 5.55 - 16.32, p= 0.001), awkward postures (OR=2.23, 95% CI 1.29 - 3.86, p= 0.004) and static postures (OR= 1.86, 95% CI 1.10 - 3.14, p= 0.021). This study showed that high prevalence of NP was associated with neck flexion or rotation, awkward and static postures.

Al-Mansoori M.H.,Sohar University | Ajiya M.,Bayero University | Mahdi M.A.,University Putra Malaysia
IEEE Photonics Journal | Year: 2012

An efficient L-band multiple-wavelength Brillouin-erbium fiber laser is presented. We configured a linear cavity resonator where the cavity ends are made up of high-reflectivity optical mirror on one side and an amplified fiber loop mirror on the other. This laser architecture provides amplification intensity-dependent transmission and allows the preamplification of the Brillouin pump (BP) signal before being injected into the Brillouin gain medium, i.e., the single-mode fiber (SMF). The technique ensures rapid reduction of erbium gain depletion, Brillouin gain saturation, and Brillouin threshold of the SMF thereby leading to the generation of higher number Brillouin Stokes lines. By utilizing only -8.5 dBm of the BP signal power, the proposed laser generates 54 Brillouin Stokes lines at BP signal wavelength of 1601.7 nm and 33 mW of the 1480-nm laser pump power. The generated channels are rigidly separated by 0.089 nm thereby becoming an attractive candidate to support the dense wavelength division multiplexing optical communication systems. © 2009-2012 IEEE.

Many algae are rich sources of sulfated polysaccharides with biological activities. The physicochemical/rheological properties and biological activities of sulfated polysaccharides are affected by the pattern and number of sulfate moieties.Sulfation of carbohydrates is catalyzed by carbohydrate sulfotransferases (CHSTs) while modification of sulfate moieties on sulfated polysaccharides was presumably catalyzed by sulfatases including formylglycine-dependent sulfatases (FGly-SULFs). Post-translationally modification of Cys to FGly in FGly-SULFs by sulfatase modifiying factors (SUMFs) is necessary for the activity of this enzyme. The aims of this study are to mine for sequences encoding algal CHSTs, FGly-SULFs and putative SUMFs from the fully sequenced algal genomes and to infer their phylogenetic relationships to their well characterized counterparts from other organisms. Algal sequences encoding CHSTs, FGly-SULFs, SUMFs, and SUMF-like proteins were successfully identified from green and brown algae. However, red algal FGly-SULFs and SUMFs were not identified. In addition, a group of SUMF-like sequences with different gene structure and possibly different functions were identified for green, brown and red algae. The phylogeny of these putative genes contributes to the corpus of knowledge of an unexplored area. The analyses of these putative genes contribute toward future production of existing and new sulfated carbohydrate polymers through enzymatic synthesis and metabolic engineering. © 2015 Ho.

Ramayah T.,Universiti Sains Malaysia | Lee J.W.C.,University Putra Malaysia | Lim S.,Universiti Sains Malaysia
Journal of Environmental Management | Year: 2012

This paper examines the determinants of recycling behaviour among 200 university students from the perspective of the Theory of Planned Behaviour (TPB). Data was analysed using Structural Equation Modelling technique. Findings indicate that environmental awareness was significantly related to attitude towards recycling, whilst attitude and social norms had significant impact on recycling behaviour. However, convenience and cost of recycling were not significant reasons for recycling. The study has enhanced the understanding of the determinants of recycling behaviour and has implications for schools and governmental agencies in educating and encouraging positive recycling behaviour. It also confirms the appropriateness of the TPB in examining studies of this nature. Further suggestions for future research are offered. © 2012 Elsevier Ltd.

Akgun A.,Karadeniz Technical University | Kincal C.,Dokuz Eylul University | Pradhan B.,University Putra Malaysia
Environmental Monitoring and Assessment | Year: 2012

In this study, landslide risk assessment for Izmir city (west Turkey) was carried out, and the environmental effects of landslides on further urban development were evaluated using geographical information systems and remote sensing techniques. For this purpose, two different data groups, namely conditioning and triggering data, were produced. With the help of conditioning data such as lithology, slope gradient, slope aspect, distance from roads, distance from faults and distance from drainage lines, a landslide susceptibility model was constructed by using logistic regression modelling approach. The accuracy assessment of the susceptibility map was carried out by the area under curvature (AUC) approach, and a 0.810 AUC value was obtained. This value shows that the map obtained is successful. Due to the fact that the study area is located in an active seismic region, earthquake data were considered as primary triggering factor contributing to landslide occurrence. In addition to this, precipitation data were also taken into account as a secondary triggering factor. Considering the susceptibility data and triggering factors, a landslide hazard index was obtained. Furthermore, using the Aster data, a land-cover map was produced with an overall kappa value of 0.94. From this map, settlement areas were extracted, and these extracted data were assessed as elements at risk in the study area. Next, a vulnerability index was created by using these data. Finally, the hazard index and the vulnerability index were combined, and a landslide risk map for Izmir city was obtained. Based on this final risk map, it was observed that especially south and north parts of the Izmir Bay, where urbanization is dense, are threatened to future landsliding. This result can be used for preliminary land use planning by local governmental authorities. © Springer Science+Business Media B.V. 2011.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Ishak A.,University of Malaya | Pop I.,Technical University of Cluj Napoca
Physica B: Condensed Matter | Year: 2011

The steady flow of an incompressible viscous fluid due to a rotating disk in a nanofluid is studied. The transformed boundary layer equations are solved numerically by a finite difference scheme, namely the Keller-box method. Numerical results for the flow and heat transfer characteristics are obtained for various values of the nanoparticle volume fraction parameter φ and suction/injection parameter h0. Two models for the effective thermal conductivity of the nanofluid, namely the MaxwellGarnett model and the Patel model, are considered. It is found that for the Patel model, the heat transfer rate at the surface increases for both suction and injection, whereas different behaviors are observed for the MaxwellGarnett model, i.e. increasing the values of φ leads to a decrease in the heat transfer rate at the surface for suction, but increases for injection. The results of this study can be used in the design of an effective cooling system for electronic components to help ensure effective and safe operational conditions. © 2011 Elsevier B.V. All rights reserved.

Rashid U.,University of Agriculture at Faisalabad | Rashid U.,Petronas | Anwar F.,University of Agriculture at Faisalabad | Anwar F.,University Putra Malaysia | Knothe G.,U.S. Department of Agriculture
Biomass and Bioenergy | Year: 2011

There is a need to seek non-conventional seed oil sources for biodiesel production due to issues such as supply and availability as well as food versus fuel. In this context, Milo (Thespesia populnea L.) seed oil was investigated for the first time as a potential non-conventional feedstock for preparation of biodiesel. This is also the first report of a biodiesel fuel produced from a feedstock containing cyclic fatty acids as T. populnea contains 8,9-methylene-8-heptadecenoic (malvalic) and smaller amounts of two cyclopropane fatty acids besides greater amounts of linoleic, oleic and palmitic acids. The crude oil extracted from T. populnea seed was transesterified under standard conditions with sodium methoxide as catalyst. Biodiesel derived from T. populnea seed oil exhibited fuel properties of density 880 kg m -3, kinematic viscosity 4.25 mm 2/s; cetane number 59.8; flash point 176 °C; cloud point 9 °C; pour point 8 °C; cold filter plugging point 9 °C; sulfur content 11 mg kg -1; water content 150 mg kg -1; ash content 15 mg kg -1; and acid value as KOH 250 mg kg -1. The oxidative stability of 2.91 h would require the use of antioxidants to meet specifications in standards. Generally, most results compared well with ASTM D6751 and EN 14214 specifications. © 2011 Elsevier Ltd.

Cheong A.M.,University of Kuala Lumpur | Tan K.W.,University of Kuala Lumpur | Tan C.P.,University Putra Malaysia | Nyam K.L.,University of Kuala Lumpur
Food Hydrocolloids | Year: 2016

The limit application of functional kenaf (Hibiscus cannabinus L.) seed oil in food and pharmaceutical industry owing to the poor water solubility and low storage stability can be overcome by the development of kenaf seed oil-in-water Pickering nanoemulsions. In this study, oil-in-water Pickering nanoemulsions were produced to investigate its stability by optimising emulsifier mixtures, namely sodium caseinate (SC), Tween 20 (T20) and β-cyclodextrin (β-CD). The interaction effects of SC and T20 on the formation of Pickering nanoemulsions with β-CD was studied and found synergistic effect among them that enhanced the stability of Pickering nanoemulsions. The optimum proportion of emulsifier mixtures obtained by employing simplex centroid mixture design was found to be 57.9% (w/w) SC, 27.6% (w/w) T20, and 14.5% (w/w) β-CD, which produced Pickering nanoemulsion with mean particle size of 155.53 nm, PDI of 0.07 and zeta-potential of -46.67 mV. These experimental values were in accordance with the predicted value, indicating the adequacy of the fitted models. The mixture design was found to be a valuable tool to optimise and study the interaction effects of different components for the development of stable Pickering nanoemulsions. © 2015 Elsevier Ltd.

Marghany M.,University Putra Malaysia
Journal of the Indian Society of Remote Sensing | Year: 2016

In this work, the genetic algorithm is utilised for automatic detection of oil spills under wind speed conditions larger than 20 ms−1. The procedure is implemented using sequences of RADARSAT-2 SAR ScanSAR Narrow single beam data acquired in the Gulf of Mexico. The study demonstrates that implementing crossover allows for generation of accurate oil spills pattern. This conclusion is confirmed by the receiver–operating characteristic (ROC) curve. The ROC curve indicates that the existence of oil slick footprints can be identified with the area under the ROC curve and the no-discrimination line of 85 %, which is greater than that of other surrounding environmental features. In conclusion, the genetic algorithm can be used as a tool for the automatic detection of oil spills and the ScanSAR Narrow single beam mode serves as an excellent sensor for oil spill detection and surveying under wind speed larger than 20 ms−1. © 2016 Indian Society of Remote Sensing

Lasekan O.,University Putra Malaysia
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2014

Purpose of review: Berries and berry extracts are known to possess properties (i.e., phenolic acids, flavonoids, and anthocyanins) that make them important in disease prevention. Observational studies have shown that many berries may hold promise for public health. However, the long-term impact of berries intake on specific populations and their functionality claims has not been fully tested. In addition, although several biological effects which are based on epidemiological studies have been explained scientifically, the mechanism of their actions is not fully understood. Therefore, this review set out to address the issue of berries intake and their potential functionality. In addition, a glimpse of what the future may hold for the berries was highlighted. Recent findings: Many of the potential health benefits of berries have been associated with their specific chemical and biological properties including their ability to modulate enzymes as well as interact, and bind to proteins. Summary: General inspection of the literature suggests that berries, such as cranberries and goji, are efficacious in the treatment of urinary tract infection and seasonal influenza, respectively. Recent study on wild blueberries has shown that they possess protective effect against cardiovascular disease. In addition, other berries have been reported to possess the ability to inhibit cervical cells (HeLa cells), modulate postprandial glucose and insulin responses. However, there is a need to address the issue of safety, efficacy, and interactions of berries intake with other dietary components. Also, more research studies should be focused on the influence of biotechnology on the functionality of berries. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Shameli K.,University Putra Malaysia
International journal of nanomedicine | Year: 2011

Silver nanoparticles (Ag NPs) were synthesized by the chemical reducing method in the external and interlamellar space of montmorillonite (MMT) as a solid support at room temperature. AgNO(3) and NaBH(4) were used as a silver precursor and reducing agent, respectively. The most favorable experimental conditions for synthesizing Ag NPs in the MMT are described in terms of the initial concentration of AgNO(3). The interlamellar space limits changed little (d-spacing = 1.24-1.47 nm); therefore, Ag NPs formed on the MMT suspension with d-average = 4.19-8.53 nm diameter. The Ag/MMT nanocomposites (NCs), formed from AgNO(3)/MMT suspension, were characterizations with different instruments, for example UV-visible, PXRD, TEM, SEM, EDXRF, FT-IR, and ICP-OES analyzer. The antibacterial activity of different sizes of Ag NPs in MMT were investigated against Gram-positive, ie, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) and Gram-negative bacteria, ie, Escherichia coli, Escherichia coli O157:H7, and Klebsiella pneumoniae, by the disk diffusion method using Mueller-Hinton agar (MHA). The smaller Ag NPs were found to have significantly higher antibacterial activity. These results showed that Ag NPs can be used as effective growth inhibitors in different biological systems, making them applicable to medical applications.

Ching Y.C.,University of Malaya | Oztop H.F.,Firat University | Rahman M.M.,Bangladesh University of Engineering and Technology | Islam M.R.,University of Malaya | Ahsan A.,University Putra Malaysia
International Communications in Heat and Mass Transfer | Year: 2012

A simulation of mixed convection heat and mass transfer in a right triangular enclosure is investigated numerically. The bottom surface of the enclosure is maintained at uniform temperature and concentration that are higher than that of the inclined surface. Moreover, the left wall of cavity moves upward (case 1) and downward (case 2) directions, which have constant flow speed, and is kept adiabatic. The enclosure represents the most common technology utilizing solar energy for desalination or waste-water treatment. A simple transformation is employed to transfer the governing equations into a dimensionless form. A finite-element scheme is used for present analysis. Comparison with the previously published work is made and found to be an excellent agreement. The study is performed for pertinent parameters such as buoyancy ratio, Richardson number and the direction of the sliding wall motion. The effect of aforesaid parameters on the flow and temperature fields as well as the heat and mass transfer rate examined. The results show that the increase of buoyancy ratio enhances the heat and mass transfer rate for all values of Richardson number and for each direction of the sliding wall motion. However, the direction of the sliding wall motion can be a good control parameter for the flow and temperature fields. © 2012 Elsevier Ltd.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Journal of Heat and Mass Transfer | Year: 2012

The unsteady boundary layer flow of a nanofluid over a permeable stretching/shrinking sheet is theoretically studied. The governing partial differential equations are transformed into ordinary ones using a similarity transformation, before being solved numerically. The results are obtained for the skin friction coefficient, the local Nusselt number and the local Sherwood number as well as the velocity, temperature and the nanoparticle fraction profiles for some values of the governing parameters, namely, the unsteadiness parameter, the mass suction parameter, the Brownian motion parameter, the thermophoresis parameter, Prandtl number, Lewis number and the stretching/shrinking parameter. It is found that dual solutions exist for both stretching and shrinking cases. The results also indicate that both unsteadiness and mass suction widen the range of the stretching/shrinking parameter for which the solution exists. © 2011 Elsevier Ltd. All rights reserved.

Zia-Ul-Haq M.,European Patent office | Riaz M.,Shaheed Benazir Bhutto University | De Feo V.,University of Salerno | Jaafar H.Z.E.,University Putra Malaysia | Moga M.,Transilvania University of Brasov
Molecules | Year: 2014

Rubus fruticosus L. is a shrub famous for its fruit called blackberry fruit or more commonly blackberry. The fruit has medicinal, cosmetic and nutritive value. It is a concentrated source of valuable nutrients, as well as bioactive constituents of therapeutic interest highlighting its importance as a functional food. Besides use as a fresh fruit, it is also used as ingredient in cooked dishes, salads and bakery products like jams, snacks, desserts, and fruit preserves. R. fruticosus contains vitamins, steroids and lipids in seed oil and minerals, flavonoids, glycosides, terpenes, acids and tannins in aerial parts that possess diverse pharmacological activities such as antioxidant, anti-carcinogenic, anti-inflammatory, antimicrobial anti-diabetic, anti-diarrheal, and antiviral. Various agrogeoclimatological factors like cultivar, environmental conditions of the area, agronomic practices employed, harvest time, post-harvest storage and processing techniques all influence the nutritional composition of blackberry fruit. This review focuses on the nutrients and chemical constituents as well as medicinal properties of different parts of R. fruticosus. Various cultivars and their physicochemical characteristics, polyphenolic content and ascorbic acid content are also discussed. The information in the present work will serve as baseline data and may lead to new biomedical applications of R. fruticosus as functional food. © 2014 by the authors.

Rosali H.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Communications in Heat and Mass Transfer | Year: 2012

This paper presents a numerical analysis of a micropolar fluid flow towards a permeable stretching/shrinking sheet in a porous medium. The governing nonlinear partial differential equations are transformed into a system of ordinary differential equations by a similarity transformation, before being solved numerically by a finite-difference scheme known as the Keller-box method. The effects of the governing parameters on the fluid flow and heat transfer characteristics are illustrated graphically. It is found that dual solutions exist for the shrinking case, whereas for the stretching case, the solution is unique. © 2012 Elsevier Ltd.

Al-Mansoori M.H.,Sohar University | Mahdi M.A.,University Putra Malaysia
Optics Express | Year: 2011

We demonstrate a widely tunable L-band multiwavelength Brillouin-erbium fiber laser utilizing a nonlinear amplified fiber loop mirror filter (AFLMF). By manipulating polarization controllers placed in the fiber loop, the erbium peak gain spectrum is able to be shifted. The nonlinear AFLMF induces wavelength-dependent cavity loss and serves as an amplitude equalizer. In addition, it provides flexibility on controlling the amount of light reflected and transmitted into and out of the laser's cavity. By utilizing 100 mW 1480 nm pump and 1.1 mW Brillouin pump power, an average of 24 stable output channels are generated by the proposed structure that could all be tuned over the whole L-band window from 1570 nm to 1610 nm. © 2011 Optical Society of America.

Kadier A.,National University of Malaysia | Simayi Y.,University Putra Malaysia | Kalil M.S.,National University of Malaysia | Abdeshahian P.,National University of Malaysia | Hamid A.A.,National University of Malaysia
Renewable Energy | Year: 2014

Hydrogen is gaining international attention as a sustainable energy carrier with the potential to replace fossil fuels. A cutting edge technology called a microbial electrolysis cell (MEC) can achieve sustainable and clean hydrogen production from a wide range of renewable biomass. A large number of substrates have been used as fuel sources. The major substrates that have been tested include wastewaters, fermentable and non-fermentable organic materials. This article mainly reviews the various substrates that have been used in MECs so far, also their resulting performance, as well as future potential substrates discussed. Besides, in this paper, a short review of recent advances in electrode material and a configuration of both the anode and cathode in MECs are provided. © 2014 Elsevier Ltd.

Rezaee Jordehi A.,University Putra Malaysia
Neural Computing and Applications | Year: 2014

Some real-world optimisation problems are dynamic; that is, their objective function and/or constraints vary over time. Solving such problems is very challenging. Particle swarm optimisation (PSO) is a well-known and efficient optimisation algorithm. In this paper, the PSO variants, devised for dynamic optimisation problems, are reviewed. This is the first comprehensive review that is conducted on PSO variants in dynamic environments. The author believes that this paper can be useful for researchers who intend to solve dynamic optimisation problems. © 2014, The Natural Computing Applications Forum.

Alitheen N.B.,University Putra Malaysia | McClure S.,CSIRO | McCullagh P.,Australian National University
Immunology and Cell Biology | Year: 2010

Interspecies variations in the processes of B-cell development and repertoire generation contrast with the greater consistency of T-cell development. B-cell development in mice and humans, with postnatal B-cell generation of new repertoire in the bone marrow throughout life, is regarded as the standard pattern. In contrast, accounts of B cells in birds, sheep, cattle, rabbits and pigs (the other species) describe cessation of gene diversification in the perinatal period, with the gut-associated lymphoid tissue (GALT) functioning as the primary lymphoid organ thereafter. It has become customary to regard the developmental pathways of T and B cells within any individual species as being as dissimilar as the functions of the two mature cell types. Reinterpretation of B-cell development patterns in different species is overdue in response to two types of reports. The first of these describe T-B crossover, specifically the intrathymic production of B cells and the extrathymic production of T cells. The second attests to the extent of sharing of B-cell developmental features across the two groups of species. We propose that, as is a feature of other haematopoietic cells, a menu of alternative B- and T-cell pathways has been retained and shared across species. A single pathway usually predominates in any species, masking alternatives. The observed predominance of any pathway is determined by factors such as placental permeability, extent of maturation of the immune system by birth and the feasibility of direct experimental intervention in development. © 2010 Australasian Society for Immunology Inc.

Ibrahim M.H.,University of Kuala Lumpur | Law S.H.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

The present paper examines the mitigating effect of social capital on the environmental Kuznets curve (EKC) for CO2 emissions using a panel data of 69 developed and developing countries. Adopting generalised method of moments (GMM) estimators, the paper finds evidence substantiating the presence of EKC. Moreover, the evidence suggests that the pollution costs of economic development tend to be lower in countries with higher social capital reservoir. Surprisingly, there is also evidence to indicate that the income threshold point beyond which CO2 emissions decline is higher in countries with higher social capital. These results are robust to addition of alternative controlled variables in the EKC specification. Thus, in addition to policy focus on investments in environmentally friendly technology and on the use of renewable energy, investments in social capital can also mitigate the pollution effects of economic progress. © 2013 Elsevier Ltd.

Praveena S.M.,Universiti Malaysia Sabah | Aris A.Z.,University Putra Malaysia
International Journal of Environmental Science and Technology | Year: 2010

The impacts of climate change and human pressure in groundwater have been greatest threats facing small islands. This paper represents a case study of groundwater responses towards the climate change and human pressures in Manukan Island Malaysia. SEAWAT-2000 was used for the simulations of groundwater response in study area. Simulations of six scenarios representing climate change and human pressures showed changes in hydraulic heads and chloride concentrations. Reduction in pumping rate and an increase in recharge rate can alter the bad effects of overdrafts in Manukan Island. In general, reduction in pumping rate and an increase in recharge rate are capable to restore and protect the groundwater resources in Manukan Island. Thus, for groundwater management options in Manukan Island, scenario 2 is capable to lessen the seawater intrusion into the aquifer and sustain water resources on a long-term basis. The selection of scenario 6 is the preeminent option during wet season. The output of this study provides a foundation which can be used in other small islands of similar hydrogeological condition for the purpose of groundwater resources protection. © IRSEN, CEERS, IAU.

Mukhtar F.,University Putra Malaysia | Oei O.T.P.S.,University of Queensland
Current Psychiatry Reviews | Year: 2011

Transforming western technology to Eastern populations, including Malaysia, presents important implications in understanding the development, maintenance, and treatment of depression. The present paper aims to review the literature on the prevalence of depression studies in Malaysia. PsycINFO, Medline databases, local journals, and 13 published articles, were included in the current review. Findings were presented in three categories i.e., 'prevalence of depression in primary care', 'general community', and 'among clinical population'. Major limitations of previous studies were noted, and thus, problems associated with the implementation and future direction of clinical and research on depression in Malaysia, was provided. In short, the contribution of empirical research on the prevalence of depression has remained inconsistent and fragmented and it is therefore, a time to venture modification. © 2011 Bentham Science Publishers.

Boretti A.,University of Ballarat | Boretti A.,Missouri University of Science and Technology | Osman A.,PROTON Holdings Berhad | Aris I.,University Putra Malaysia
International Journal of Hydrogen Energy | Year: 2011

This short communication proposes novel two stroke engine burning hydrogen in oxygen in presence of large amounts of steam as residual gases. This engine has a bowl-in-piston combustion chamber, exhaust valves only and it uses direct injection of hydrogen, oxygen and water. Diesel-like compression ignition combustion is achieved by injecting the oxygen and the hydrogen in the surrounding steam close to a continuously operated glow plug. The operation of the engine is simulated by commercial softwares. The water injection enables acceptable metal temperatures and reduced heat losses. First computational results show brake efficiencies above 55% achieved with mass of water injected about twice the mass of oxygen and hydrogen mixture and operation with a significant amount of exhaust gas recirculation. It seems reasonable to guess efficiencies of the fully optimised and developed engine approaching the 60% mark, 20% higher than those of the state-of-the-art H2ICEs designed for operation with air using the spark-ignition engine concept as well as of those projected for Diesel engines operating with exhaust energy recovery. Worth of mention is also the much higher power density following the two stroke operation. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Pour Ebrahim N.,University Putra Malaysia
Open House International | Year: 2015

The concept of community where people can meet their needs, interact, and feel a sense of belonging and togetherness has been an interesting topic for a majority of professionals in different academic fields such as urban planning and urban design. Different theories in these disciplines assert the correlation between the built environment and sense of community. Among these theories, New Urbanism is one of the most important schools of thought which have thrown light on this correlation. New Urbanism claims that the built environment can create a sense of community among its users. As the theory of New Urbanism develops more and more among professionals across the world, it is critical that we give the topic more research attention. This study intends to begin moving us in this direction by reviewing some studies which tried to achieve the social goal of new urbanism in recent years. Therefore the results of the empirical assessment of Sense of community in different neighbourhoods are reviewed and the influence of physical design on different domains of sense of community are discussed to find out whether the claims of new urbanism in creating sense of community could be trusted in the future development. While new urbanism movement continues to become more popular, finding enough evidence for its social claims might encourage more planners to use its principles as a way to improve the residents' social life.

Rakhimov I.S.,University Putra Malaysia
Journal of Physics: Conference Series | Year: 2016

The concept of central extensions plays an important in constructing extensions of algebras. This technique has been successfully used in the classification problem of certain classes of algebras. In 1978 Skjelbred and Sund reduced the classification of nilpotent Lie algebras in a given dimension to the study of orbits under the action of automorphism group on the space of second degree cohomology of a smaller Lie algebra with coefficients in a trivial module. Then W. de Graaf applied the Skjelbred and Sund method to the classification problem of low-dimensional nilpotent Lie and associative algebras over some fields. The main purpose of this note is to establish elementary properties of central extensions of associative dialgebras and apply the above mentioned method to the classification of low dimensional nilpotent associative dialgebras. © Published under licence by IOP Publishing Ltd.

Lai K.S.,University Putra Malaysia
Plant Cell, Tissue and Organ Culture | Year: 2016

Exocyst is an octameric protein complex that mediates the tethering of secretory vesicles at the plasma membrane for exocytosis. In this study, a 1136 bp promoter fragment of exocyst subunit exo70 family protein C2 (EXO70C2) was fused with the β-glucuronidase (GUS) reporter gene and introduced into Arabidopsis thaliana via Agrobacterium tumefaciens. Detail histochemical analysis of EXO70C2-GUS expression in T3 transgenic A. thaliana lines revealed a strong GUS activity at late stages of pollen development. Strong GUS signals were visible from post meiotic pollen, mature pollen and pollen release stages. There was no detectable expression of EXO70C2-GUS during early pollen development and meiosis stages. Consistent with the GUS assay, EXO70C2 transcript profiling using real-time PCR analysis also showed high expression of EXO70C2 at these late stages of pollen development. Further RNA in situ hybridisation revealed the presence of EXO70C2 signals in pollen and as well as anther tapetum. Taken together, these results indicate that, EXO70C2 is specifically expressed in pollen and anther tapetum during the late stages of pollen development, suggesting its function in regulating essential secretory vesicles to support pollen maturation. © 2015, Springer Science+Business Media Dordrecht.

Dahlan N.D.,University Putra Malaysia | Jones P.J.,University of Cardiff | Alexander D.K.,University of Cardiff
Building and Environment | Year: 2011

This study assessed the influences of operative temperature on occupants' perceptions of indoor thermal condition in three non-air-conditioned multi-storey hostels in Klang Valley, Malaysia. The thermal conditions of 24 measured rooms were recorded with and without an operating ceiling fan from May until July 2007. Measurements were made simultaneously at three different floor levels, namely, at the first, fifth and top floor of each of the case study hostels. A questionnaire survey was completed by 298 female student occupants of the same case study hostels. The results suggested that even though a significance above p < 0.01 was recorded between the operative temperatures with and without fan operation, the temperature difference remained small, i.e., from 0.5 K to 1 K. The findings of the questionnaire survey showed that the occupants perceived the thermal conditions in rooms that were shaded with a projected balcony (shading ratio of 0.9), a long roof overhang (shading ratio of 1.6) and an operable window-to-wall ratio of 0.3 to be thermally comfortable. © 2010 Elsevier Ltd.

Uthumporn U.,Universiti Sains Malaysia | Zaidul I.S.M.,University Putra Malaysia | Karim A.A.,Universiti Sains Malaysia
Food and Bioproducts Processing | Year: 2010

Native granular starches (corn, cassava, mung bean, and sago) were hydrolyzed using a mixture of alpha-amylase and glucoamylase at 35 °C for 24 h. Hydrolyzed starches were analyzed for the degree of hydrolysis and for physicochemical and functional properties. Corn starch showed the highest degree of hydrolysis, as evidenced by the presence of distinct pores penetrating deep into the granules. Enzymatic erosion occurred mainly at the surface for cassava, whereas isolated porous structures were observed in hydrolyzed mung bean and sago starch. The amylose content was significantly lower in all starches except for sago starch. The powder X-ray diffraction of all starches showed no significant changes after hydrolysis, but hydrolyzed starches showed a more crystalline nature. The action of enzymes caused significant changes in some pasting properties and in the swelling/solubility of starches. Evidently, enzymes were able to hydrolyze granular starches to a variable degree at sub-gelatinization temperature, and produced a relatively high degree of conversion. © 2009 The Institution of Chemical Engineers.

Nourani V.,University of Tabriz | Pradhan B.,University Putra Malaysia | Ghaffari H.,Islamic Azad University at Mahabad | Sharifi S.S.,University of Tabriz
Natural Hazards | Year: 2014

Without a doubt, landslide is one of the most disastrous natural hazards and landslide susceptibility maps (LSMs) in regional scale are the useful guide to future development planning. Therefore, the importance of generating LSMs through different methods is popular in the international literature. The goal of this study was to evaluate the susceptibility of the occurrence of landslides in Zonouz Plain, located in North-West of Iran. For this purpose, a landslide inventory map was constructed using field survey, air photo/satellite image interpretation, and literature search for historical landslide records. Then, seven landslide-conditioning factors such as lithology, slope, aspect, elevation, land cover, distance to stream, and distance to road were utilized for generation LSMs by various models: frequency ratio (FR), logistic regression (LR), artificial neural network (ANN), and genetic programming (GP) methods in geographic information system (GIS). Finally, total four LSMs were obtained by using these four methods. For verification, the results of LSM analyses were confirmed using the landslide inventory map containing 190 active landslide zones. The validation process showed that the prediction accuracy of LSMs, produced by the FR, LR, ANN, and GP, was 87.57, 89.42, 92.37, and 93.27 %, respectively. The obtained results indicated that the use of GP for generating LSMs provides more accurate prediction in comparison with FR, LR, and ANN. Furthermore; GP model is superior to the ANN model because it can present an explicit formulation instead of weights and biases matrices. © 2013 Springer Science+Business Media Dordrecht.

Najafi-Sharjabad F.,University Putra Malaysia
Global journal of health science | Year: 2013

Family planning has been cited as essential to the achievement of Millennium Development Goals (MDG). Family planning has a direct impact on women's health and consequence of each pregnancy. The use of modern contraception among Asian women is less than global average. In Asia a majority of unintended pregnancies are due to using traditional contraceptive or no methods which lead to induced unsafe abortion. Cultural attitudes, lack of knowledge of methods and reproduction, socio demographic factors, and health service barriers are the main obstacles to modern contraceptive practice among Asian women. Culturally sensitive family planning program, reforming health system, and reproductive health education through mass media to create awareness of the benefits of planned parenthood are effective strategies to improve modern contraceptive practice among Asian women.

Saeid P.,University Putra Malaysia
Research Journal of Chemistry and Environment | Year: 2011

Structural geology, tectonics, lithology and the courses of major rivers play an important role for development of the landscapes and changing the environmental behaviors in Zagros Mountains. The Karun and the Dez rivers in Zagros Mountains are greatly influenced by the structural geology, particularly the topographic barrier of the Mountain Front Fault and the structural lows of its associated lateral ramps. The research has been attempted at finer scales and it shows that the river courses are more variable with similar river reaches in similar tectonic scenarios apparently having different responses; diverting around uplifting areas in some instances and cutting across them in others during the Quaternary period and therefore impacts the environment and ecology in some minor extends. In this study the river responses also were investigated and interpreted using an integration of remote sensing, GIS, GPS, geomorphology and field survey to study the tectonic signatures, especially in the Mesopotamian Foreland Basin where the river systems are very mobile and able to respond, both laterally and vertically, to the active tectonics and its behavior on environment. In semi-arid foreland basin it has been found that the river response to structural uplift was greatly influenced by the location and timing of movement of the river channel relative to the location and timing of the uplift in the study area.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Nazar R.,National University of Malaysia
Meccanica | Year: 2011

The unsteady laminar flow of an incompressible micropolar fluid over a stretching sheet is investigated. The unsteadiness in the flow and temperature fields is caused by the time-dependence of the stretching velocity and the surface temperature. Effects of the unsteadiness parameter, material parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. © 2010 Springer Science+Business Media B.V.

Gannasin S.P.,University Putra Malaysia
Molecules (Basel, Switzerland) | Year: 2012

Hydrocolloid from tamarillo (Solanum betaceum Cav.) puree was extracted using water and characterised for the first time. Proximate compositions of the extracted hydrocolloid were also determined. Functional characteristics such as water-holding capacity, oil-holding capacity, emulsifying activity, emulsion stability, foaming capacity and stability of the hydrocolloid were evaluated in comparison to that of commercial hydrocolloids. Its functional groups and degree of esterification were determined using Fourier Transform Infrared (FT-IR) spectroscopy. Monosaccharide profiling was done using reverse-phase high pressure liquid chromatography (RP-HPLC). Screening of various fruits for high hydrocolloid yield after water extraction resulted in tamarillo giving the highest yield. The yield on dry weight basis was 8.30%. The hydrocolloid constituted of 0.83% starch, 21.18% protein and 66.48% dietary fibre with 49.47% degree of esterification and the monosaccharides identified were mannose, ribose, rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose. Higher oil-holding capacity, emulsifying activity and emulsion stability compared to commercial hydrocolloids propose its possible application as a food emulsifier and bile acid binder. Foaming capacity of 32.19% and good foam stabilisation (79.36% of initial foam volume after 2 h of foam formation) suggest its promising application in frothy beverages and other foam based food products. These findings suggest that water-extracted tamarillo hydrocolloid can be utilised as an alternative to low methoxyl pectin.

Hassan S.,University Putra Malaysia
Information Technology Journal | Year: 2010

The aim of this study is to examine the potential of Soft Systems Methodology (SSM) in the development of environment-aware Case-Based Reasoning (CBR) system. Having awareness of the computing system's environment is useful either for providing information or factor that can affect the system or effected by the events occur in the environment. The CBR system with environment awareness is able to employ realtime contextual information available in the environment. This information or knowledge will contribute to improve the problem descriptions as well as the solutions, in which the system not only depend on information given by user and historical cases. However, resources available in the environment need to be identified prior to the implementation of environment-aware CBR system. This requires an appropriate analysis methodology to build an explicit model of the system's environment to capture relevant environment knowledge for the system. This study presents the SSM analysis in the development of environment-aware CBR system. The discussion is illustrated with reference to the partial analysis of an environment-aware CBR system development. The deliverable of this initial analysis is an explicit model of the system's environment for environment-aware CBR system. © 2010 Asian Network for Scientific Information.

Imteaz M.A.,Swinburne University of Technology | Ahsan A.,University Putra Malaysia | Shanableh A.,University of Sharjah
Resources, Conservation and Recycling | Year: 2013

A daily water balance model is used for the performance analysis and design optimisation of rainwater tanks at four different regions of Melbourne; North, Central, South-East and South-West. These four different regions of Melbourne are characterised by notable different topography and rainfall characteristics. From historical rainfall data, three representative years (dry, average and wet) are selected. Reliability is defined as percentage of days in a year when rainwater tank is able to supply the intended partial demand for a particular condition. For the three climatic conditions, a number of reliability charts are produced for domestic rainwater tanks in relation to tank volume, roof area and number of people in a house (i.e. water demand). It is found that for a relatively small roof size (100 m2), 100% reliability cannot be achieved even with a very large tank (10,000 L). Reliability becomes independent of tank size for tank sizes larger than 4000-7000 L depending on the location. This is defined as threshold tank size, relationships with threshold tank sizes and annual rainfall amounts are then established for all the locations. A new factor named 'Rainwater Accumulation Potential (RAP)' has been introduced and maximum achievable reliabilities for different reasonable RAPs under different climatic conditions are presented for all the locations selected in this study. From these findings, for the design of rainwater tank size it is recommended to have a RAP value of 0.8-0.9 for greater Melbourne. © 2013 Elsevier B.V. All rights reserved.

Nehdi I.A.,King Saud University | Sbihi H.,King Saud University | Tan C.P.,University Putra Malaysia | Al-Resayes S.I.,King Saud University
Bioresource Technology | Year: 2012

Lepidium sativum L. (garden cress) is a fast growing annual herb, native to Egypt and west Asia but widely cultivated in temperate climates throughout the world. L. sativum seed oil (LSO) extracted from plants grown in Tunisia was analyzed to determine whether it has potential as a raw material for biodiesel production. The oil content of the seeds was 26.77%, mainly composed of polyunsaturated (42.23%) and monounsaturated (39.62%) fatty acids. Methyl esters (LSOMEs) were prepared by base-catalyzed transesterification with a conversion rate of 96.8%. The kinematic viscosity (1.92 mm2/s), cetane number (49.23), gross heat value (40.45), and other fuel properties were within the limits for biodiesel specified by the ASTM (American Standard for Testing and Materials). This study showed that LSOMEs have the potential to supplement petroleum-based diesel.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
International Journal of Heat and Mass Transfer | Year: 2012

The boundary layer of an unsteady two-dimensional stagnation-point flow of a nanofluid is further investigated. The similarity equations are solved numerically for three types of nanoparticles, namely copper (Cu), alumina (Al 2O 3), and titania (TiO 2) in the water based fluid with Prandtl number Pr = 6.2. The skin friction coefficient, the local Nusselt number, and the velocity and temperature profiles are presented and discussed. Effects of the solid volume fraction parameter φ on the fluid flow and heat transfer characteristics are thoroughly examined. Interesting observation is that there are dual solutions seen for negative values of the unsteadiness parameter A (decelerating flow with A < 0). © 2012 Elsevier Ltd. All rights reserved.

Rahman M.M.,Bangladesh University of Engineering and Technology | Oztop H.F.,Firat University | Ahsan A.,University Putra Malaysia | Orfi J.,King Saud University
International Journal of Heat and Mass Transfer | Year: 2012

Finite element method is used in this study to analyze the effects of buoyancy ratio and Lewis number on heat and mass transfer in a triangular cavity with zig-zag shaped bottom wall. Buoyancy ratio is defined as the ratio of Grashof number of solutal and thermal. Inclined walls of the cavity have lower temperature and concentration according to zig-zag shaped bottom wall. Enclosed space consists mostly of an absorber plate and two inclined glass covers that form a cavity. Both high temperature and high concentrations are applied to bottom corrugated wall. Computations were done for different values of buoyancy ratio (-10 ≤ Br ≤ 10), Lewis number (0.1 ≤ Le ≤ 20) and thermal Rayleigh number (10 4 ≤ Ra T ≤ 10 6). Streamlines, isotherms, iso-concentration, average Nusselt and Sherwood numbers are obtained. It is found that average Nusselt and Sherwood numbers increase by 89.18% and 101.91% respectively as Br increases from -10 to 20 at Ra T = 10 6. Also, average Nusselt decreases by 16.22% and Sherwood numbers increases by 144.84% as Le increases from 0.1 to 20 at this Rayleigh number. © 2012 Elsevier Ltd. All rights reserved.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
International Journal of Heat and Mass Transfer | Year: 2012

An analysis is carried out to investigate the steady two-dimensional stagnation-point flow of a water based nanofluid over an exponentially stretching/shrinking sheet in its own plane. Using a similarity transformation, the governing mathematical equations are transformed into coupled, nonlinear ordinary differential equations which are then solved numerically for three types of nanoparticles, namely copper (Cu), alumina (Al 2O 3), and titania (TiO 2) in the water based fluid with Prandtl number Pr = 6.2. The skin friction coefficient, the local Nusselt number and the velocity and temperature profiles are presented graphically and discussed. Effects of the solid volume fraction and the stretching/shrinking parameter λ on the fluid flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. The range of the parameter λ where the similarity solution exists for the steady stagnation-point flow over an exponentially stretching/shrinking sheet is larger compared with the linear stretching/shrinking case. © 2012 Elsevier Ltd. All rights reserved.

Ooi C.P.,University Putra Malaysia
Cochrane database of systematic reviews (Online) | Year: 2011

Mild cognitive impairment (MCI) is an intermediate state between normal cognition and dementia in which daily function is largely intact. This condition may present an opportunity for research into the prevention of dementia. Carbohydrate is an essential and easily accessible macronutrient which influences cognitive performance. A better understanding of carbohydrate-driven cognitive changes in normal cognition and mild cognitive impairment may suggest ways to prevent or reduce cognitive decline. To assess the effectiveness of carbohydrates in improving cognitive function in older adults. We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register on 22 June 2010 using the terms: carbohydrates OR carbohydrate OR monosaccharides OR disaccharides OR oligosaccharides OR polysaccharides OR CARBS. ALOIS contains records from all major healthcare databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many trial databases and grey literature sources. All randomised controlled trials (RCT) that have examined the efficacy of any form of carbohydrates in normal cognition and MCI. One review author selected and retrieved relevant articles for further assessment. The remaining authors independently assessed whether any of the retrieved trials should be included. Disagreements were resolved by discussion.  There is no suitable RCT of any form of carbohydrates involving independent-living older adults with normal cognition or mild cognitive impairment. There are no suitable RCTs on which to base any recommendations about the use of any form of carbohydrate for enhancing cognitive performance in older adults with normal cognition or mild cognitive impairment. More studies of many different carbohydrates are needed to tease out complex nutritional issues and further evaluate memory improvement.

Loughlan J.,Loughborough University | Yidris N.,University Putra Malaysia
Thin-Walled Structures | Year: 2014

This paper examines the effect of the local support conditions at the ends of the constituent plates of plain channel section columns when subjected to uniformly compressed loading. The buckling and post-buckling interactive response of the columns have been determined through the development of suitable finite element modelling strategies and solution procedures which take due account of the influence of material nonlinearity and geometrical imperfections. Uniformly compressed loading means, of course, fixed conditions at the column ends with respect to global rotations and the ends of the constituent plates of the cross-section can be treated as either locally rotationally constrained or locally rotationally free. These two conditions are shown to lead to quite different characteristic interactive responses of the columns due to amplitude modulation in the buckling mode for the rotationally constrained case. © 2014 Elsevier Ltd.

Anezaki K.,Japan Institute for Environmental Sciences | Kannan N.,University Putra Malaysia | Nakano T.,Osaka University
Environmental science and pollution research international | Year: 2015

This study reports the concentrations and congener partners of polychlorinated biphenyls (PCBs) in commercially available paints. Polycyclic-type pigments containing dioxazine violet (pigment violet (PV) 23, PV37) and diketopyrrolopyrrole (PR254, PR255) were found to contain PCB-56, PCB-77, PCB-40, PCB-5, and PCB-12, and PCB-6, PCB-13, and PCB-15, respectively, as major congeners. Dioxazine violet is contaminated with by-products during synthesis from o-dichlorobenzene, which is used as a solvent during synthesis, and diketopyrrolopyrrole is contaminated with by-products during synthesis from p-chlorobenzonitrile. The concentration of PCBs in paint containing PV23 or PV37 was 0.050-29 mg/kg, and toxic equivalency (TEQ) values ranged 1.1-160 pg-TEQ/g. The concentration of PCBs in paint containing PR254 or PR255 was 0.0019-2.4 mg/kg. Naphthol AS is an azo-type pigment, and PCB-52 was detected in paint containing pigment red (PR) 9 with 2,5-dichloroaniline as its source. PCB-146, PCB-149, and PCB-153 were identified from paint containing PR112 produced from 2,4,5-trichloroaniline, as major congeners. These congeners have chlorine positions similar to aniline, indicating that these congeners are by-products obtained during the synthesis of pigments. The concentrations of PCBs in paints containing PR9 and PR112 were 0.0042-0.43 and 0.0044-3.8 mg/kg, respectively. The corresponding TEQ for PR112 was 0.0039-8.6 pg-TEQ/g.

Homayouni S.M.,Islamic Azad University | Tang S.H.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

According to previous researches, automated guided vehicles and quay cranes in container terminals have a high potential synergy. In this paper, a mixed integer programming model is formulated to optimize the coordinated scheduling of cranes and vehicles in container terminals. Objectives of the model are to minimize total traveling time of the vehicles and delays in tasks of cranes. A genetic algorithm is developed to solve the problem in reasonable computational time. The most appropriate control parameters for the proposed genetic algorithm are investigated in a medium size numerical test case. It is shown that balanced crossover and mutation rates have the best performance in finding a near optimal solution for the problem. Then, ten small size test cases are solved to evaluate the performance of the proposed optimization methods. The results show the applicability of the genetic algorithm since it can find near optimal solutions, precisely and accurately. © 2013 Seyed Mahdi Homayouni and Sai Hong Tang.

Rahimian F.P.,University of Central Lancashire | Ibrahim R.,University Putra Malaysia
Design Studies | Year: 2011

Conventional Computer Aided Design tools lack intuitivity for being used in conceptual architectural design process. This paper identifies the impact of using a haptic based VR 3D sketching interface for integrating novice designers' cognitions and actions to improve design creativity. This study employs protocol analysis for comparing the collective cognitive and collaborative design protocols of three pairs of novice architectural designers in both 3D and manual sketching sessions. Results show that the simple and tangible haptic based design interface improved designers' cognitive and collaborative activities. These improvements also increased their engagement with 'problem-space' and 'solution-space' that led towards more artefact maturity. Research findings from this study can help the development of cutting-edge haptic-based collaborative virtual environments in architectural education and associated professions. © 2010 Elsevier Ltd. All rights reserved.

Moradi Golsheikh A.,University of Malaya | Huang N.M.,University of Malaya | Lim H.N.,University Putra Malaysia | Zakaria R.,University of Malaya | Yin C.-Y.,Murdoch University
Carbon | Year: 2013

Silver-nanoparticles-decorated reduced graphene oxide (rGO) was electrodeposited on indium tin oxide (ITO) by a cyclic voltammetry method. The results of X-ray diffraction, Fourier-transform infrared transmission spectroscopy and Raman spectroscopy confirmed the simultaneous formation of cubic phase silver nanoparticles and reduction of GO through the electrodeposition process. Field emission scanning electron microscope images showed a uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution on the RGO sheets, which could only be achieved using silver ammonia complex instead of silver nitrate as precursor. The composite deposited on ITO exhibited notable electrocatalytic activity for the reduction of H2O2, leading to an enzymeless electrochemical sensor with a fast amperometric response time less than 2 s. The corresponding calibration curve of the current response showed a linear detection range of 0.1-100 mM (R2 = 0.9992) while the limit of detection was estimated to be 5 μM. © 2013 Elsevier Ltd. All rights reserved.

Imteaz M.A.,Swinburne University of Technology | Rahman A.,University of Western Sydney | Ahsan A.,University Putra Malaysia
Resources, Conservation and Recycling | Year: 2012

A spreadsheet based daily water balance model is used for the performance analysis and design optimisation of rainwater tanks at two different regions of Melbourne, South-East and Central Melbourne. These two different regions of Melbourne are characterised by notable different topography and rainfall characteristics. From historical rainfall data, three representative years (dry, average and wet) are selected. Reliability is defined as percentage of days in a year when rainwater tank is able to supply the intended partial demand for a particular condition. For the three climatic conditions, a number of reliability charts are produced for domestic rainwater tanks in relations to tank volume, roof area, number of people in a house (i.e. water demand) and percentage of total water demand to be satisfied by the harvested rainwater. It is found that for a relatively small roof size (100 m 2), 100% reliability cannot be achieved even with a very large tank (10,000 L). Reliability becomes independent of tank size for tank sizes larger than 5000-7000 L depending on the location. This is defined as threshold tank size, relationships with threshold tank sizes and annual rainfall amounts are then established for both the locations. It is found that for a particular annual rainfall amount, threshold tank size for South-East Melbourne is higher than that of Central Melbourne. However, for a relatively large roof size (200 m 2), approximately 90% reliability can be achieved with a tank size of 10,000 L and with further increase in tank size, a 100% reliability is achievable, except in a dry year. Furthermore, it is found that reliabilities for South-East Melbourne maintain consistent higher values as compared to Central Melbourne. © 2012 Elsevier B.V.

Alang Ahmad S.A.,University of Sheffield | Alang Ahmad S.A.,University Putra Malaysia | Wong L.S.,University of Manchester | Ul-Haq E.,University of Sheffield | And 3 more authors.
Journal of the American Chemical Society | Year: 2011

An approach to the integration of nanolithography with synthetic chemical methodology is described, in which near-field optical techniques are used to selectively deprotect films formed by the adsorption of aminosilanes protected by modified 2-nitrophenylethoxycarbonyl (NPEOC) groups. The NPEOC groups are functionalized at the m- or p-position with either a tetraethyleneglycol or a heptaethylene glycol adduct. We describe the synthesis of these bioresistant aminosilanes and the characterization of the resulting photoreactive films. Photodeprotection by exposure to UV light (λ = 325 nm) yielded the amine with high efficiency, at a similar rate for all four adsorbates, and was complete after an exposure of 2.24 J cm-2. Following photodeprotection, derivatization by trifluoroacetic anhydride was carried out with high efficiency. Micropatterned samples, formed using a mask, were derivatized with aldehyde-functionalized polymer nanoparticles and, following derivatization with biotin, were used to form patterns of avidin-coated polymer particles. Fluorescence microscopy and atomic force microscopy data demonstrated that the intact protecting groups conferred excellent resistance to nonspecific adsorption. Nanometer-scale patterns were created using scanning near-field photolithography and were derivatized with biotin. Subsequent conjugation with avidin-functionalized polymer nanoparticles yielded clear fluorescence images that indicated dense attachment to the nanostructures and excellent protein resistance on the surrounding surface. These simple photocleavable protecting group strategies, combined with the use of near-field exposure, offer excellent prospects for the control of surface reactivity at nanometer resolution in biological systems and offer promise for integrating the top-down and bottom-up molecular fabrication paradigms. © 2011 American Chemical Society.

Hamdan O.,Malaysian Forest Research Institute | Khali Aziz H.,Malaysian Forest Research Institute | Mohd Hasmadi I.,University Putra Malaysia
Remote Sensing of Environment | Year: 2014

This study has been carried out to evaluate the relationship between Advanced Land Observing Satellite (ALOS) Phased Array L-band SAR (PALSAR) backscattering coefficients and the aboveground biomass (AGB) of a managed mangrove forest in Malaysia. Matang Mangrove Forest Reserve known as Matang Mangroves was selected as the study area. It covers about 41,000ha of mangrove forest and is the largest single mangrove ecosystem in Peninsular Malaysia. A mosaic of L-band PALSAR fine beam dual (FBD) with 25mpixel spacing data for the year 2010 was provided by the Japan Aerospace Exploration Agency's (JAXA) within the framework of the ALOS Kyoto and Carbon (K&C) Initiative. A total of 320 sampling plots that were collected in 2010 and 2011 were used in the study. The calculated plot-based AGB were correlated to the pixels/backscatter of PALSAR data. The best correlation function (i.e. from HV backscatter) was used to estimate and determine the aboveground biomass of the Matang Mangroves. The study found that the estimated AGB in Matang Mangroves ranged between 2.98 and 378.32±33.90Mgha-1 with an average of 99.40±33.90Mgha-1 and a total AGB of about 4.25 million Mg. The HV backscatter started to saturate at an AGB of 100Mgha-1 and the errors associated with the estimation occurred largely when the AGB exceeded 150Mgha-1. The study also found that the manipulation of polarisation was useful in discriminating succession levels of mangroves. © 2014 Elsevier Inc.

Shu M.-H.,University of Malaya | Appleton D.,University Putra Malaysia | Zandi K.,University of Malaya | AbuBakar S.,University of Malaya
BMC Complementary and Alternative Medicine | Year: 2013

Background: Gracilaria changii (Xia et Abbott) Abbott, Zhang et Xia, a red algae commonly found in the coastal areas of Malaysia is traditionally used for foods and for the treatment of various ailments including inflammation and gastric ailments. The aim of the study was to investigate anti-inflammatory, gastroprotective and anti-ulcerogenic activities of a mass spectrometry standardized methanolic extract of Gracilaria changii.Methods: Methanolic extract of Gracilaria changii (MeOHGCM6 extract) was prepared and standardized using mass spectrometry (MS). Anti-inflammatory activities of MeOHGCM6 extract were examined by treating U937 cells during its differentiation with 10 μg/ml MeOHGCM6 extract. Tumour necrosis factors-α (TNF-α) response level and TNF-α and interleukin-6 (IL-6) gene expression were monitored and compared to that treated by 10 nM betamethasone, an anti-inflammatory drug. Gastroprotective and anti-ulcerogenic activities of MeOHGCM6 extract were examined by feeding rats with MeOHGCM6 extract ranging from 2.5 to 500 mg/kg body weight (b.w.) following induction of gastric lesions. Production of mucus and gastric juice, pH of the gastric juice and non-protein sulfhydryls (NP-SH) levels were determined and compared to that fed by 20 mg/kg b.w. omeprazole (OMP), a known anti-ulcer drug.Results: MS/MS analysis of the MeOHGCM6 extracts revealed the presence of methyl 10-hydroxyphaeophorbide a and 10-hydroxypheophytin a, known chlorophyll proteins and several unidentified molecules. Treatment with 10 μg/ml MeOHGCM6 extract during differentiation of U937 cells significantly inhibited TNF-α response level and TNF-α and IL-6 gene expression. The inhibitory effect was comparable to that of betamethasone. No cytotoxic effects were recorded for cells treated with the 10 μg/ml MeOHGCM6 extract. Rats fed with MeOHGCM6 extract at 500 mg/kg b.w. showed reduced absolute ethanol-induced gastric lesion sizes by > 99% (p < 0.05). This protective effect was comparable to that conferred by OMP. The pH of the gastric mucus decreased in dose-dependent manner from 5.51 to 3.82 and there was a significant increase in NP-SH concentrations.Conclusions: Results from the study, suggest that the mass spectrometry standardized methanolic extract of Gracillaria changii possesses anti-inflammatory, gastroprotective and anti-ulcerogenic properties. Further examination of the active constituent of the extract and its mechanism of action is warranted in the future. © 2013 Shu et al.; licensee BioMed Central Ltd.

Raoov M.,University of Malaya | Raoov M.,University Putra Malaysia | Mohamad S.,University of Malaya | Abas M.R.,University of Malaya
Journal of Hazardous Materials | Year: 2013

Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) was firstly synthesized using functionalized β-Cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using toluene diisocyanate (TDI) linker to form insoluble βCD-BIMOTs-TDI. SEM characterization result shows that βCD-BIMOTs-TDI exhibits macropore size while the BET result shows low surface area (1.254m2g-1). The unique properties of the ILs allow us to produce materials with different morphologies. The adsorption isotherm and kinetics of 2,4-dichlorophenol (2,4-DCP) onto βCD-BIMOTs-TDI is studied. Freundlich isotherm and pseudo-second order kinetics are found to be the best to represent the data for 2,4-DCP adsorption on the βCD-BIMOTs-TDI. The presence of macropores decreases the mass transfer resistance and increases the adsorption process by reducing the diffusion distance. The change in entropy (δS°) and heat of adsorption (δH°) for 2,4-DCP on βCD-BIMOTs-TDI were estimated as -55.99J/Kmol and -18.10J/mol, respectively. The negative value of Gibbs free energy (δG°) indicates that the adsorption process is thermodynamically feasible, spontaneous and chemically controlled. Finally, the interactions between the cavity of βCD-BIMOTs and 2,4-DCP are investigated and the results shows that the inclusion of the complex formation and π-π interaction are the main processes involved in the adsorption process. © 2013 Elsevier B.V.

Vasudevan R.,University Putra Malaysia
Genetics and molecular research : GMR | Year: 2011

Variable number of tandem repeats (VNTR) polymorphism in the interleukin 4 (IL-4) gene has been associated with end-stage renal disease (ESRD) subjects in many different populations, although with conflicting results. We determined the 70 bp of VNTR polymorphism at intron 3 of the IL-4 gene in Malaysian ESRD subjects. Buccal cells were collected from 160 case and 160 control subjects; genomic DNA was amplified using PCR, followed by agarose gel electrophoresis. There were significant differences in genotypes and alleles of the IL-4 gene. We conclude that VNTR polymorphism of the IL-4 gene is a risk factor for the development of ESRD among Malaysians.

Sidique S.F.,University Putra Malaysia | Joshi S.V.,Michigan State University | Lupi F.,Michigan State University
Resources, Conservation and Recycling | Year: 2010

This study analyzes the effects of various recycling and waste management policy variables on recycling rate by utilizing county-level panel data from Minnesota covering the period 1996-2004. The policy variables examined include variable pricing for waste disposal, expenditure on recycling education, provision of curbside recycling services and drop-off centers, and enactment of recycling ordinances. Unlike previous studies, this study accounts for the cumulative effects of the expenditure variable on recycling rate and also investigates whether different recycling programs such as curbside and drop-off recycling act as complements or substitutes in increasing recycling rates. This study also examines the effect of income and demographic characteristics on recycling rate. After accounting for random effects and endogenous variables, the results indicate that variable pricing of waste disposal increases the rate of recycling. Other policy variables such as the enactment of recycling ordinances and cumulative expenditures on recycling education are also found to be effective measures to increase recycling rate. © 2009 Elsevier B.V. All rights reserved.

Banerjee M.,Indian Institute of Technology Kanpur | Banerjee S.,Polytechnic University of Turin | Banerjee S.,University Putra Malaysia
Mathematical Biosciences | Year: 2012

In this paper we consider a modified spatiotemporal ecological system originating from the temporal Holling-Tanner model, by incorporating diffusion terms. The original ODE system is studied for the stability of coexisting homogeneous steady-states. The modified PDE system is investigated in detail with both numerical and analytical approaches. Both the Turing and non-Turing patterns are examined for some fixed parametric values and some interesting results have been obtained for the prey and predator populations. Numerical simulation shows that either prey or predator population do not converge to any stationary state at any future time when parameter values are taken in the Turing-Hopf domain. Prey and predator populations exhibit spatiotemporal chaos resulting from temporal oscillation of both the population and spatial instability. With help of numerical simulations we have shown that Turing-Hopf bifurcation leads to onset of spatio-temporal chaos when predator's diffusivity is much higher compared to prey population. Our investigation reveals the fact that Hopf-bifurcation is essential for the onset of spatiotemporal chaos. © 2011 Elsevier Inc.

Chin M.J.,University of Selangor | Poh P.E.,University of Selangor | Tey B.T.,University of Selangor | Chan E.S.,University of Selangor | Chin K.L.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

The generation of palm oil mill effluent (POME) alongside with the production of crude palm oil has created environmental issue for the palm oil mill industry in Malaysia due to its polluting characteristics. POME with its high organic content is a source with great potential for biogas production. However, POME is commonly treated using open ponding system just to comply with government regulation without capturing biogas released from the process. Biogas generated from anaerobic digestion of POME can replace palm kernel shell and mesocarp fiber which has higher economic value as boiler fuel; upgraded to be used in gas engine for power generation. It is estimated that net profit of RM 3.8 million per year can be obtained in a palm oil mill with processing capacity of 60 tonnes/hr from electricity generation using biogas produced from POME treatment. This review paper will elaborate on the potential of POME as a source of renewable energy and the challenges faced by the palm oil mills in Malaysia which deters the development of biogas plants in the mill. © 2013 Elsevier Ltd.

Rheumatoid arthritis (RA) is an autoimmune disease with unknown etiology. Anticitrullinated protein autoantibody has been documented as a highly specific autoantibody associated with RA. Protein arginine deiminase type 4 (PAD4) is the enzyme responsible for catalyzing the conversion of peptidylarginine into peptidylcitrulline. PAD4 is a new therapeutic target for RA treatment. In order to search for inhibitors of PAD4, structure-based virtual screening was performed using LIDAEUS (Ligand discovery at Edinburgh university). Potential inhibitors were screened experimentally by inhibition assays. Twenty two of the top-ranked water-soluble compounds were selected for inhibitory screening against PAD4. Three compounds showed significant inhibition of PAD4 and their IC50 values were investigated. The structures of the three compounds show no resemblance with previously discovered PAD4 inhibitors, nor with existing drugs for RA treatment. Three compounds were discovered as potential inhibitors of PAD4 by virtual screening. The compounds are commercially available and can be used as scaffolds to design more potent inhibitors against PAD4.

Pourghasemi H.R.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia | Gokceoglu C.,Hacettepe University | Moezzi K.D.,B. Science graduate of environment
Geomatics, Natural Hazards and Risk | Year: 2013

In a country with diverse geologic, topographic and climatic conditions such as Iran, landslides are frequent phenomena. The aim of this study is to perform a landslide susceptibility assessment at Haraz watershed, Iran using two different approaches such as Dempster-Shafer and Weights-of-evidence models in GIS. First, a landslide inventory map was prepared using the landslide occurrence data by interpreting aerial photographs and field surveys. Second, thematic maps including lithology, altitude, and land-use are prepared in GIS. A total 11 landslide conditioning factors are considered such as slope angle, aspect, altitude, distance from drainage, distance from road, distance from river, lithology, land use, topographic wetness index, stream power index and slope-length (LS). The relationship between the conditional factors and the landslides were calculated using both Dempster-Shafer and Weights-of-evidence models. Using the predicted values, landslide susceptibility maps of the study area is produced. For verification, the results of the analyses were then compared with the field-verified landslide locations. Additionally, the receiver operating characteristics (ROC) curves for all landslide susceptibility models were drawn and the area under curve values was calculated. The AUC value of the produced landslide susceptibility maps has been obtained as 72.87% and 79.87% for Dempster-Shafer and Weights-of-evidence models, respectively. The resulting susceptibility maps would be useful for landuse planning and prioritization of efforts for the reduction and mitigation of future landslide hazards in Haraz watershed. © 2013 Copyright Taylor and Francis Group, LLC.

Azadi M.,Islamic Azad University at Qazvin | Pourakbar S.,University Putra Malaysia | Kashfi A.,Islamic Azad University at Qazvin
Tunnelling and Underground Space Technology | Year: 2013

Currently with the spread of tunnel constructions in cities, the proximity of other structures being built close to these tunnels have now become an important subject. Studying the rate of settlement of structures built in the vicinity of these tunnels could be an importance as well. The distance between tunnels and buildings is an important factor which can also be taken to account. Considering some of the parameters in place, favorable results can be achieved in having tunnels and other structures in the close proximity of each other.In this paper, the settlement of structures with different scenarios has been studied. The proximity of structures and their orientation in comparison with the location of the tunnels has also been a part of this study. Through the Finite Element Method (FEM), and with the use of Neural Network (NN), a various settlement situations have been studied. Using NN on the analysis of the FEM outcome and consideration of the vertical and horizontal distances between the tunnels and constructions with the number of their stories and the diameter of tunnel, relation between the settlements of constructions in any given direction will be immerge. In the study of this matter, the use of methods such as NN and genetic algorithms has not been reported. Using NN to evaluate the results can help to optimize the construction and implementation of underground structures. © 2013 Elsevier Ltd.

Hairuddin A.A.,University of Southern Queensland | Hairuddin A.A.,University Putra Malaysia | Yusaf T.,University of Southern Queensland | Wandel A.P.,University of Southern Queensland
Renewable and Sustainable Energy Reviews | Year: 2014

Homogeneous charge compression ignition (HCCI) engine uses a relatively new mode of combustion technology. In principle, there is no spark plug or injector to assist the combustion, and the combustion auto-ignites in multiple spots once the mixture has reached its chemical activation energy. The challenges in developing HCCI engines are the difficulties in: controlling the auto-ignition of the mixture and the heat release rate at high load operations, achieving a cold start, meeting emission standards and controlling knock. At low engine speeds, early auto-ignition can occur, possibly leading to knocking, while late auto-ignition at high engine speeds will make HCCI susceptible to misfire. Hydrogen greatly reduces emissions levels but with reduced power. However, when hydrogen is combined with diesel in dual-fuel mode, low NOx, CO and particulate matter (PM) emissions levels can be achieved, and engine efficiency can be increased by 13-16%. Numerical methods are commonly used to predict HCCI engines' performance (i.e. emissions levels, brake thermal efficiency and combustion phasing), which is cost-effective compared to solely relying on experimentation. The multi-zone method promises better simulation results compared to the single-zone model by combining detailed chemical kinetics with simplified 3D modeling so that turbulence and inhomogeneity in the mixture are considered; good agreement between simulations and experiments have been achieved. Specific strategies used in the experimental method (e.g. fuel additives, inlet air heating, inlet air pressurizing, exhaust gas recirculation (EGR) and injection methods), and numerical method (e.g. single-zone and multi-zone models, mixing model, turbulence model and multi-dimensional model), and other issues associated with HCCI engines are discussed in this paper. © 2014 Elsevier Ltd.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

An analysis is carried out to study the steady two-dimensional stagnation-point flow and heat transfer from a warm, laminar liquid flow to a melting stretching/shrinking sheet. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, before being solved numerically using the Runge-Kutta-Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. © 2010 Elsevier B.V.

Shamsuri A.A.,National University of Malaysia | Shamsuri A.A.,University Putra Malaysia | Daik R.,National University of Malaysia
Reviews on Advanced Materials Science | Year: 2015

In this paper, we reviewed the applications of hydrophilic and hydrophobic ionic liquids including their mixtures particularly between ionic liquids and chemical compounds for preparation of advanced polymer blends and composites. In the preceding researches we have found that ionic liquids and their mixtures could be effectively used as environmentally friendly solvent, plasticizer, coupling agent and compatibilizer. These materials have the ability to improve properties of polymer blends and composites that consisted of natural and synthetic polymers. On the other hand, we also included our previous and other studies that consumed the mixture of ionic liquids and chemical compounds for preparation of polymer blends and composites in the form of aerogels, films, composite films and biocomposites. © 2015 Advanced Study Center Co. Ltd.

Chemoprevention has become an important area in cancer research due to the failure of current therapeutic modalities. Epidemiological and preclinical studies have demonstrated that nutrition plays a vital role in the etiology of cancer. This study was conducted to determine the chemopreventive effects of germinated brown rice (GBR) in rats induced with colon cancer. GBR is brown rice that has been claimed to be richer in nutrients compared to the common white rice. The male Sprague Dawley rats (6 weeks of age) were randomly divided into 5 groups: (G1) positive control (with colon cancer, unfed with GBR), (G2) fed with 2.5 g/kg of GBR (GBR (g)/weight of rat (kg)), (G3) fed with 5 g/kg of GBR, (G4) fed with 10 g/kg of GBR and (G5) negative control (without colon cancer, unfed with GBR). GBR was administered orally once daily via gavage after injection of 15 mg/kg of body weight of azoxymethane (AOM) once a week for two weeks, intraperitonially. After 8 weeks of treatment, animals were sacrificed and colons were removed. Colonic aberrant crypt foci (ACF) were evaluated histopathologically. Total number of ACF and AC, and multicrypt of ACF, and the expression of beta-catenin and COX-2 reduced significantly (p < 0.05) in all the groups treated with GBR (G2, G3 and G4) compared to the control group (G1). Spearman rank correlation test showed significant positive linear relationship between total beta-catenin and COX-2 score (Spearman's rho = 0.616, p = 0.0001). It is demonstrated that GBR inhibits the development of total number of ACF and AC, and multicrypt of ACF, reduces the expression of beta-catenin and COX-2, and thus can be a promising dietary supplement in prevention of colon cancer.

Lasekan O.,University Putra Malaysia
Journal of the Science of Food and Agriculture | Year: 2013

BACKGROUND: Volatile compounds play a key role in determining the sensory appreciation of vegetable oils. In this study a systematic evaluation of odorants responsible for the characteristic flavour of roasted tigernut oil was carried out. RESULTS: A total of 75 odour-active volatiles were identified. From these, 13 aroma compounds showing high flavour dilution factors in the range of 16 to 128 were quantified by their odour activity values (OAVs). On the basis of high OAVs in oil, the following aroma compounds [vanillin (chocolate, sweet vanilla), 5-ethylfurfural (caramel, spicy), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (caramel), phenyl acetaldehyde (honey-like), ethanone, 1-(4-hydroxy-3-methoxyphenyl) (faint vanilla)] were elucidated as important contributors to the overall chocolate, sweet vanilla, butterscotch aroma of the oil. CONCLUSION: Odorants with high concentrations in the roasted tigernut oil such as 5-hydroxymethylfurfural, ethyl hexadecanoate, n-propyl-9,12-octadecadienoate gave relatively low OAVs, so their contributions to the overall orthonasal aroma impression of roasted tigernut oil can be assumed to be low. © 2012 Society of Chemical Industry.

Gomes C.,University Putra Malaysia
International Journal of Biometeorology | Year: 2012

This paper addresses a concurrent multidisciplinary problem: animal safety against lightning hazards. In regions where lightning is prevalent, either seasonally or throughout the year, a considerable number of wild, captive and tame animals are injured due to lightning generated effects. The paper discusses all possible injury mechanisms, focusing mainly on animals with commercial value. A large number of cases from several countries have been analyzed. Economically and practically viable engineering solutions are proposed to address the issues related to the lightning threats discussed. © 2012 ISB.

Nehdi I.A.,King Saud University | Sbihi H.,King Saud University | Tan C.P.,University Putra Malaysia | Al-Resayes S.I.,King Saud University
Food Chemistry | Year: 2013

The physicochemical properties, fatty acid, tocopherol, thermal properties, 1H NMR, FTIR and profiles of non-conventional oil extracted from Citrullus colocynthis (L.) Schrad seeds were evaluated and compared with conventional sunflower seed oil. In addition, the antioxidant properties of C. colocynthis seed oil were also evaluated. The oil content of the C. colocynthis seeds was 23.16%. The main fatty acids in the oil were linoleic acid (66.73%) followed by oleic acid (14.78%), palmitic acid (9.74%), and stearic acid (7.37%). The tocopherol content was 121.85 mg/100 g with γ-tocopherol as the major one (95.49%). The thermogravimetric analysis showed that the oil was thermally stable up to 286.57 °C, and then began to decompose in four stages namely at 377.4 °C, 408.4 °C, 434.9 °C and 559.2 °C. The present study showed that this non-conventional C. colocynthis seed oil can be used for food and non-food applications to supplement or replace some of the conventional oils. © 2012 Elsevier Ltd. All rights reserved.

Pourghasemi H.R.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia | Gokceoglu C.,Hacettepe University
Natural Hazards | Year: 2012

The main goal of this study is to produce landslide susceptibility maps of a landslide-prone area (Haraz) in Iran by using both fuzzy logic and analytical hierarchy process (AHP) models. At first, landslide locations were identified by aerial photographs and field surveys, and a total of 78 landslides were mapped from various sources. Then, the landslide inventory was randomly split into a training dataset 70 % (55 landslides) for training the models and the remaining 30 % (23 landslides) was used for validation purpose. Twelve data layers, as the landslide conditioning factors, are exploited to detect the most susceptible areas. These factors are slope degree, aspect, plan curvature, altitude, lithology, land use, distance from rivers, distance from roads, distance from faults, stream power index, slope length, and topographic wetness index. Subsequently, landslide susceptibility maps were produced using fuzzy logic and AHP models. For verification, receiver operating characteristics curve and area under the curve approaches were used. The verification results showed that the fuzzy logic model (89. 7 %) performed better than AHP (81. 1 %) model for the study area. The produced susceptibility maps can be used for general land use planning and hazard mitigation purpose. © 2012 Springer Science+Business Media B.V.

Lim S.A.H.,Manufacture and Engineering Management | Lim S.A.H.,University Putra Malaysia | Antony J.,Manufacture and Engineering Management | Albliwi S.,Manufacture and Engineering Management
Trends in Food Science and Technology | Year: 2014

This paper presents a systematic review on the reported implementation of Statistical Process Control (SPC) in the food industry. The final selection comprehends 41 articles selected and comprehensively analysed to assess SPC development in the food industry through its motivations, benefits, challenges and limitations. Key outputs indicated from the review include: reduced process variability and conformance to the food regulations are the biggest motivations; resistance to accept SPC is the most cited challenge; lack of statistical knowledge is the most common limitation and the biggest benefits for implementing SPC in the food industry are improved food safety and reduced process variation. © 2014 Elsevier Ltd.

Paterson R.R.M.,IBB Institute for Biotechnology And Bioengineering | Sariah M.,University Putra Malaysia | Lima N.,IBB Institute for Biotechnology And Bioengineering
Crop Protection | Year: 2013

Palm oil is a very important commodity. It is added to numerous products and is a biofuel. However, oil palms (OP) are subjected to fungal diseases of which Fusarium wilt and Ganoderma rots are the most important. Considerations of how climate change (CC) affects tropical economic plants are limited and for OP are even fewer. The margin for adapting to higher temperatures and changing humidity is reduced in tropical OP. Land will become increasingly unsuitable for growing OP and the plants will become stressed allowing ingress of fungal diseases. New land will be increasingly suitable where the environmental conditions are less severe than in the tropics. Novel diseases may threaten the crop. Finally, the effect of the major consequences of CC on OP fungal diseases is considered herein with a view to establishing key hypotheses. © 2013 Elsevier Ltd.

Islam A.,Universiti Malaysia Sabah | Taufiq-Yap Y.H.,University Putra Malaysia | Chu C.-M.,Universiti Malaysia Sabah | Chan E.-S.,University of Selangor | Ravindra P.,Universiti Malaysia Sabah
Process Safety and Environmental Protection | Year: 2013

The production of biodiesel is gaining momentum with the ever increasing demand of the fuel. Presently, limited literature is available with respect to well designed solid heterogeneous catalyst for biodiesel production considering all the characteristics, process and operation parameters. Hence, a study was conducted to design effective heterogeneous catalyst for biodiesel production. Further, the significant impact of different catalysts, different feed stock, various reaction conditions such as temperature, methanol oil molar ratio, catalyst concentrations and stability/inactivation of the catalysts, are detailed out for transesterification process of biodiesel production. Based on the studies it can be concluded that well designed heterogeneous catalyst can yield high throughput of biodiesel. © 2012 The Institution of Chemical Engineers.

Majeed K.,University of Technology Malaysia | Majeed K.,COMSATS Institute of Information Technology | Jawaid M.,University Putra Malaysia | Hassan A.,University of Technology Malaysia | And 4 more authors.
Materials and Design | Year: 2013

The increasing demand for new food packaging materials which satisfy people requirements provided thrust for advancement of nano-materials science. Inherent permeability of polymeric materials to gases and vapours; and poor barrier and mechanical properties of biopolymers have boosted interest in developing new strategies to improve these properties. Research and development in polymeric materials coupled with appropriate filler, matrix-filler interaction and new formulation strategies to develop composites have potential applications in food packaging. Advancement in food packaging materials expected to grow with the advent of cheap, renewable and sustainable materials with enhanced barrier and mechanical properties. Nanoparticles have proportionally larger surface area and significant aspect ratio than their micro-scale counterparts, which promotes the development of mechanical and barrier properties. Nanocomposites are attracting considerable interest in food packaging because of these fascinating features. On the other hand, natural fibres are susceptible to microorganisms and their biodegradability is one of the most promising aspects of their incorporation in polymeric materials. Present review article explain about different categories of nanoclay and natural fibre based composite with particular regard to its applications as packaging materials and also gives an overview of the most recent advances and emerging new aspects of nanotechnology for development of hybrid composites for environmentally compatible food packaging materials. © 2012 Elsevier Ltd.

Huda A.S.N.,University of Malaya | Mekhilef S.,University of Malaya | Ahsan A.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

Bangladesh has been experiencing several problems over the past few decades. These include over population, energy crisis and global warming, etc. Adequate amount of power generation in a sustainable way is an important issue for rapidly increasing population and economic development. Renewable energy can play an effective role to meet energy demand. Since it is an agrarian country, biomass is one of the potential renewable energy sources in Bangladesh. Agricultural crop residues, animal manure and municipal solid waste are the major sources of biomass energy in the country. This paper presents the scope, potential and technologies related to the use of biomass resources. The study also discusses the biomass projects undertaken by the government and non-government organizations, plans and strategies to promote biomass technologies in Bangladesh. © 2013 Elsevier Ltd. All rights reserved.

Kong K.W.,University of Malaya | Mat-Junit S.,University of Malaya | Ismail A.,University Putra Malaysia | Aminudin N.,University of Malaya | Abdul-Aziz A.,University of Malaya
Food Chemistry | Year: 2014

The polyphenolic profiles and antioxidant activities of the water extracts of Barringtonia racemosa shoots (leaves and stems) were explored. Two methods, freeze drying and air drying, for preparation of the shoots, were also compared. Freeze drying was better as air drying caused 5-41% reduction of polyphenols. Three phenolic acids and three flavonoids were identified, using UHPLC. The descending order of polyphenols in the leaves and stems was gallic acid > ellagic acid > quercetin > protocatechuic acid > rutin > kaempferol. In vitro antioxidant analyses were performed using biological samples. In the LDL oxidation assay, B. racemosa leaf extract (IC50 = 73.0 μg/ml) was better than stem extract (IC50 = 226 μg/ml) at inhibiting the formation of TBARS and lipid hydroperoxides. Similar trends were observed for serum and haemoglobin oxidation. B. racemosa leaf extract was better than its stem extract in delaying the time required to oxidise haemoglobin to methaemoglobin. The high polyphenolic content of B. racemosa shoots could have contributed towards their antioxidative effects. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

Mukhtar F.,University Putra Malaysia | Oei T.P.S.,University of Queensland
Depression Research and Treatment | Year: 2011

This paper aimed to review the literature on depression that focused on its assessment and treatment in Malaysia. PsycINFO, Medline, local journals were searched, and 18 published articles were included in this paper. Results indicate that research on depression in Malaysia, particularly validation studies and psychotherapy research, was weak and fragmented, with minimal empirical evidence available. Pharmacotherapy still dominated the treatment for depression, and, in terms of psychotherapy, Cognitive Behavioural Therapy (CBT) was recently practiced, but only a few studies have reported on the treatment efficacy of CBT. Major limitations of studies were noted, and, consequently, the problems that are associated with the implementation and future direction of clinical and research on depression in Malaysia were discussed. In short, the contribution of empirical research on the assessment and treatment for depression remained inconsistent and fragmented and urgently in need of further empirical investigation. © 2011 Firdaus Mukhtar and Tian P. S. Oei.

Sbihi H.M.,King Saud University | Nehdi I.A.,King Saud University | Tan C.P.,University Putra Malaysia | Al-Resayes S.I.,King Saud University
Energy Conversion and Management | Year: 2014

Recently, biodiesel has been gaining market share against fossil-origin diesel due to its ecological benefits and because it can be directly substituted for traditional diesel oils. However, the high cost of the raw materials required to produce biodiesel make it more expensive than fossil diesel. Therefore, low-priced raw materials, such as waste cooking oil and animal fats, are of interest because they can be used to drive down the cost of biodiesel. We have produced biodiesel from camel fat using a transesterification reaction with methanol in the presence of NaOH. The experimental variables investigated in this study were the temperature (30-75 C), reaction time (20-160 min), catalyst concentration (0.25-1.5%), and methanol/fat molar ratio (4:1-9:1). A maximum biodiesel yield of 98.6% was obtained. The fuel properties of biodiesel, such as iodine value, saponification value, density, kinematic viscosity, cetane number, flash point, sulfur content, carbon residue, water and sediment, high heating value, refractive index, cloud point, pour point, and distillation characteristics, were measured. The properties were compared with EN 14214 and ASTM 6751 biodiesel standards, and an acceptable level of agreement was obtained. © 2013 Elsevier Ltd. All rights reserved.

Mohamed S.,University Putra Malaysia
Trends in Food Science and Technology | Year: 2014

Metabolic syndrome is a condition of at least three of the cardiovascular risk factors: obesity, excessive visceral fat storage, dyslipidemia, hypertension and hyperglycaemia or Type 2 diabetes. It is a state of insulin resistance, oxidative stress and chronic inflammation. Cardiovascular disease is the highest cause of death globally. Certain dietary components and over 800 plants help prevent or moderate metabolic syndrome by assisting the body homeostasis mechanisms. This review compiles the most current studies on foods that help fight metabolic syndrome and the scientific evidences to support their use. This includes functional fats, digestive enzymes inhibitors, various beverages, different fruits, specific vegetables, grains, legumes, herbs and spices that can reduce cardiovascular disease risk, through several cellular mechanisms. © 2013 Elsevier Ltd.

Jusoff K.,University Putra Malaysia
Polish Journal of Environmental Studies | Year: 2013

Mangrove forests are one of the most productive and bio-diverse wetland environments on earth. Yet these unique coastal tropical forest environments are among the most threatened habitats in the world. Some key progress points in mangrove conservation, restoration, and research in Malaysia are highlighted. Based on an intensive literature review, the ecology and ecological management, distribution and areas of existing mangroves in the world and Malaysia, issues associated with mangrove conservation and restoration are discussed. Growing in the intertidal areas and estuary mouths between land and sea, mangroves provide critical habitat for diverse marine and terrestrial flora and fauna. Important for the flora and fauna is the opportunity to continue living in a sustainable environment and in suitable conditions. A potential stand is the place that obtains the possibility of germination and establishment of a plant species according to their physical, chemical, and biological demands. In many cases it is seen that because of unsuitable selection of site and species, afforestation and reforestation projects are forced to fail after spending time, cost, and labor. The population boom and rapid economic developments have greatly reduced mangrove areas in Malaysia despite the Malaysian government launching a series of programs to protect mangroves in the 1980s and establishing mangrove ecosystems as high-priority areas for improving environmental and living resource management The issues, threats, and significant values of mangroves also were highlighted. A more systematic protection strategy using ecological engineering management-based, active restoration and rehabilitation measurements still are urgently needed in order to preserve these valuable resources in Malaysia.

Kumar R.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia | Rashid S.A.,University Putra Malaysia | Matsuura T.,University of Ottawa
RSC Advances | Year: 2013

Biocompatible and naturally occurring chitosan was used as an additive for the preparation of a polysulfone ultrafiltration membrane. Two different compositions of polysulfone in N-methylpyrrolidone (NMP) and chitosan in 1% acetic acid were blended to prepare PSf-CS ultrafiltration membranes by the diffusion induced phase separation (DIPS) method. The proper blending of polysulfone and chitosan in PSf-CS membranes was confirmed by ATR-IR analysis. The surface and cross-sectional morphology of the membranes was studied by scanning electron microscopy (SEM). The membrane hydrophilicity was determined by water uptake and contact angle measurements. The PSf-CS membrane showed an enhanced hydrophilicity compared to a PSf ultrafiltration membrane. The time dependent permeation studies revealed the improved flux of PSf-CS membranes. PSf-CS membranes were subjected to bovine serum albumin (BSA) protein rejection studies. An improved antifouling property was observed for PSf-CS blend membranes as compared to pristine PSf ultrafiltration membranes. Both the permeation and antifouling properties of PSf-CS membranes increased with an increase in chitosan composition. © 2013 The Royal Society of Chemistry.

Kumar R.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia | Rashid S.A.,University Putra Malaysia | Ahmed A.A.,King Fahd University of Petroleum and Minerals
Desalination | Year: 2013

Polysulfone (PSf) and chitosan (CS) blend membranes were prepared by incorporating titanium dioxide nanotubes (TiO2NT) in different compositions. The proper blending of PSf and CS in the PSf/CS/TiO2 membranes was confirmed by ATR-IR spectroscopy. The influence of nanotubes on morphology of membranes was investigated by Field Emission Scanning Electron Microscopy (FESEM). The effect of nanotubes on hydrophilicity of the membranes was studied by water swelling and contact angle measurements. The distribution of TiO2NT on the membrane surface was determined by Transmission Electron Microscope (TEM) analysis. The permeation property of PSf/CS/TiO2NT membranes was carried out by measuring the time dependent pure water flux (PWF). Bovine serum albumin (BSA) protein rejection studies were performed to know the antifouling properties. The rheological percolation threshold of PSf/CS/TiO2NT solutions was measured by viscosity studies. The nanotubes incorporated PSf/CS membranes showed enhanced permeation and antifouling properties compared to PSf/CS and nascent PSf ultrafiltration membranes. Membranes prepared well above rheological percolation threshold showed drastic reduction in pore size and acted as nanofiltration (NF) membranes. © 2013 Elsevier B.V.

Lee H.V.,University of Malaya | Juan J.C.,University of Malaya | Taufiq-Yap Y.H.,University Putra Malaysia
Renewable Energy | Year: 2015

A simple method was developed for biodiesel production from non-edible Jatropha oil which contains high free fatty acid using a bifunctional acid-base catalyst. The acid-base catalyst comprising CaO and La2O3 mixed metal oxides with various Ca/La atomic ratios were synthesized via co-precipitation method. The effects of Ca/La compositions on the surface area, acidity-basicity and transesterification activity were investigated. Integrated metal-metal oxide between Ca and La enhanced the catalytic activity due to well dispersion of CaO on composite surface and thus, increased the surface acidic and basic sites as compared to that of bulk CaO and La2O3 metal oxide. Furthermore, the transesterification reactions resulted that the catalytic activity of CaO-La2O3 series were increased with Ca/La atomic ratio to 8.0, but the stability of binary system decreased by highly saturated of CaO on the catalyst surface at Ca/La atomic ratio of 10.0. The highest biodiesel yield (98.76%) was achieved under transesterification condition of 160°C, 3h, 25 methanol/oil molar ratio and 3wt.%. In addition, the stability of CaO-La2O3 binary system was studied. In this study, Ca-La binary system is stable even after four cycles with negligible leaching of Ca2+ ion in the reaction medium. © 2014 Elsevier Ltd.

Djojodihardjo H.,University Putra Malaysia
Advances in the Astronautical Sciences | Year: 2015

The present work assess the effect of the Earth's oblateness parameters, particularly J2 and J3, on the formation flight of micro satellites in near equatorial low orbits. The modified Hill-Clohessy-Wiltshire equations are extended to include the J2 and J3 effects in the LVLH frame of reference. The primary gravitational perturbation effect is due to the equatorial bulge term, J2. The J2 term changes the orbit period, a drift in perigee, a nodal precession rate and periodic variations in all the orbital elements. The J2 zonal harmonic captures the equatorial bulge of the Earth, and is the largest coefficient describing the Earth's shape. There is about a 21km difference in equatorial and polar radii due mainly to this bulge. In the Earth orbit about 800 km altitude, the J2 effect is much larger in comparison with other perturbations such as atmospheric drag, solar radiation pressure and electro-magnetic effects. The modified linearized Hill-Clohessy-Wiltshire to take into account the influence of J2 and J3 is utilized to determine the orbits of twin spacecraft in formation flight in Near Equatorial orbits, where the variation of J2 is less apparent. A simplified approach, capitalizing on the balance between linearized approach and expected fidelity of the obtained solution, has been synthesized to arrive at a linearized J2 and J3 modified HCW equation. The computational results obtained are assessed by comparison to Schweighart-Sedwick formula. The significance and relevance of the influence of these parameters in the determination and design of formation flying orbits are assessed through parametric study. As a particular example, for low earth orbit (i.e. 847 km), the error is about 0.25km from the desired relative position in the LVLH or Hill frame after 16.67 hours. Further comparison to similar results in the literature exhibits the plausibility of the work.

Izadi M.,University Putra Malaysia | Ab Kadir M.Z.A.,Islamic Azad University at Firoozkooh | Hajikhani M.,Aryaphase Company
Journal of Electrical Engineering and Technology | Year: 2013

Lightning electromagnetic fields are important issues for the evaluation of lightning induced overvoltage on power lines and for setting the appropriate protection level for power networks. Such electromagnetic fields are strongly dependent on lightning return stroke currents at different heights along the lightning channel. On the other hand, the ground reflection factor due to the difference between the return stroke channel impedance and the equivalent ground impedance at channel base can have an effect on the shape of the return stroke currents by entering additional reflected currents into the channel. In this paper, the effect of the ground reflection factor on the return stroke currents at different heights along a channel and the electromagnetic fields associated with the lightning channel at close distances are considered. Moreover, the behavior of the electromagnetic fields versus the reflection factor changes and the radial distance changes are considered and the results are discussed accordingly. The results illustrate that the reflection factor has a direct relationship with the values of the electromagnetic fields while this is usually ignored in earlier studies.

Rezaee Jordehi A.,University Putra Malaysia
Neural Computing and Applications | Year: 2014

Big bang–big crunch (BBBC) algorithm is a fairly novel gradient-free optimisation algorithm. It is based on theories of evolution of the universe, namely the big bang and big crunch theory. The big challenge in BBBC is that it is easily trapped in local optima. In this paper, chaotic-based strategies are incorporated into BBBC to tackle this challenge. Five various chaotic-based BBBC strategies with three different chaotic map functions are investigated and the best one is selected as the proposed chaotic strategy for BBBC. The results of applying the proposed chaotic BBBC to different unimodal and multimodal benchmark functions vividly show that chaotic-based BBBC yields quality solutions. It significantly outperforms conventional BBBC, cuckoo search optimisation and gravitational search algorithm. © 2014, Springer-Verlag London.

Tohidi E.,Islamic Azad University at Zahedan | Kilicman A.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

A new collocation method is developed for solving BVPs which arise from the problems in calculus of variation. These BVPs result from the Euler-Lagrange equations, which are the necessary conditions of the extremums of problems in calculus of variation. The proposed method is based upon the Bernoulli polynomials approximation together with their operational matrix of differentiation. After imposing the collocation nodes to the main BVPs, we reduce the variational problems to the solution of algebraic equations. It should be noted that the robustness of operational matrices of differentiation with respect to the integration ones is shown through illustrative examples. Complete comparisons with other methods and superior results confirm the validity and applicability of the presented method. © 2013 Emran Tohidi and Adem Kiliçman.

Hasan A.,University of Malaya | Abbas A.,Quaid-i-Azam University | Akhtar M.N.,University Putra Malaysia
Molecules | Year: 2011

A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the reaction mixture onto crushed ice. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The 1,3,5-triaryl-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible spectrum when irradiated with ultraviolet radiation. The fluorescent behavior of these compounds was studied by UV-Vis and emission spectroscopy, performed at room temperature. © 2011 by The Authors.

JubouriAl_Ogaili T.A.,University Putra Malaysia
International Journal of Applied Linguistics and English Literature | Year: 2016

This study will examine postcolonial powers of opposition in Octavia Butler’s Kindred (1979); through Homi Bhabha’s concept of ambivalence and Edward Said’s self-other relationship. By using these concepts, this research aims to unravel how the colonized and the colonizer perceive each in the selected works. It will offer an in-depth analysis of the thematic and ideological characteristics of selected works. Thus, the focus will mainly be on the theme of the mutual relationship between the colonized and the colonizer in the selected works. This relationship is specified to the concept of ambivalence. This concept incarnates the dual, yet, uncontrolled relationship between the colonized and the colonizer. Nevertheless, the colonized considers the colonizer as oppressive but an envious power; and the colonizer judges the colonized as inferior but indigenous. The colonial relationship will also be revealed by using the concept of self-other. Such concept scrutinizes the way the colonized and the colonizer perceive and resist each other. Accordingly, the research’s main focus point is the power relationship developed in the light of colonial ambivalence and self-other continuum. The research’s methodology relies on Bhabha’s concept of ambivalence and Edward Said’s self-other relationship. In The Location of Culture (1994), Bhabha maintains that the concept of ambivalence conveys “the exercise of colonialist authority, however, requires the production of differentiations, individuations, identity effects through which discriminatory practices can map out subject populations that are tarred with the visible and transparent mark of power” (111). Edward Said, in his discussion of self-other relationship in Orientalism (1979), argues that selfother relationship is “the vacillation [inconstancy] between the familiar [self] and the alien [other]” (72). © 2016, Australian International Academic Centre PTY LTD. All rights reserved.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Danquah M.K.,Monash University
Chemical Engineering Journal | Year: 2011

Increasing global energy demands and the potential for significant climate change have led to burgeoning interest in alternative fuels which are sustainable, environmentally friendly and cost efficient. One of the key options is to produce bioethanol from renewable biomass. Due to its numerous advantages, including fast growth rate, non-edibility, and the ability to accumulate substantial amounts of carbohydrates, microalgae, a second generation cellular biomass, have the potential to be used as a fermentation feedstock for bioethanol production. The present study examines the enzymatic hydrolysis of Chloroccum sp. by using cellulase obtained from Trichoderma reesei, ATCC 26921. The hydrolysis was conducted under varying conditions of temperature, pH and substrate concentration, with constant enzyme dosage. The kinetics of hydrolysis was fitted with Michaelis-Menten's model of rapid equilibrium. The highest glucose yield of 64.2% (w/w) was obtained at a temperature of 40°C, pH 4.8, and a substrate concentration of 10g/L of microalgal biomass. Comparative kinetic studies on glucose and cellobiose formation showed twice as fast glucose production than cellulobiose. The value of K m,app was higher for the hydrolysis of cellobiose (K m,app=15.18g/L) compared to that of the substrate (K m,app=1.48g/L), thus displaying a competitive type of inhibition. The results were in keeping with the obtained reaction velocities. Overall, the enzymatic hydrolysis process proved to be an effective mechanism to enhance the saccharification process of microalgal biomass. © 2011 Elsevier B.V.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
PLoS ONE | Year: 2013

The steady boundary layer flow of a viscous and incompressible fluid over a moving vertical flat plate in an external moving fluid with viscous dissipation is theoretically investigated. Using appropriate similarity variables, the governing system of partial differential equations is transformed into a system of ordinary (similarity) differential equations, which is then solved numerically using a Maple software. Results for the skin friction or shear stress coefficient, local Nusselt number, velocity and temperature profiles are presented for different values of the governing parameters. It is found that the set of the similarity equations has unique solutions, dual solutions or no solutions, depending on the values of the mixed convection parameter, the velocity ratio parameter and the Eckert number. The Eckert number significantly affects the surface shear stress as well as the heat transfer rate at the surface. © 2013 Bachok et al.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Danquah M.K.,Monash University
Process Biochemistry | Year: 2011

The utilisation of microalgal biomass as feedstock for bioethanol production has been very promising owing to the large amounts of carbohydrates embedded in the physiology of the microalgal cell. This is coupled with the potential of microalgae to achieve targets required for high growth rate bioethanol production, climate change mitigation and economic growth. The high content of complex carbohydrates entrapped in the cell wall of the microalgae makes it essential to incorporate a pre-treatment stage to release and convert these complex carbohydrates into simple sugars prior to the fermentation process. Hence, this study explores the influence of acid exposure as a microalgal pre-treatment strategy for bioethanol production. Different parameters were investigated: acid concentration, temperature, microalgae loading and pre-treatment time. A central composite design technique was employed to optimize the acid pre-treatment conditions. Results showed that the highest bioethanol concentration obtained was 7.20 g/L and this was achieved when the pre-treatment step was performed with 15 g/L of microalgae at 140 °C using 1% (v/v) of sulphuric acid for 30 min. In terms of ethanol yield, ∼52 wt% (g ethanol/g microalgae) maximum was obtained using 10 g/L of microalgae and 3% (v/v) of sulphuric acid under 160 °C for 15 min. The statistical analysis revealed amongst the parameters investigated that temperature is the most critical factor during acid pre-treatment of microalgae for bioethanol production. © 2010 Elsevier Ltd. All rights reserved.

Yusof R.,University of Technology Malaysia | Abdul Rahman R.Z.,University Putra Malaysia | Khalid M.,University of Technology Malaysia | Ibrahim M.F.,National University of Malaysia
Journal of the Franklin Institute | Year: 2011

A technique for the modeling of nonlinear control processes using fuzzy modeling approach based on the TakagiSugeno fuzzy model with a combination of genetic algorithm and recursive least square is proposed. This paper discusses the identification of the parameters at the antecedent and consequent parts of the fuzzy model. For the antecedent fuzzy parameters, genetic algorithm is used to tune them while at the consequent part, recursive least squares approach is used to identify the system parameters. This approach is applied to a process control rig with three subsystems: a heating element, a heat exchanger and a compartment tank. Experimental results show that the proposed approach provides better modeling when compared with Takagi Sugeno fuzzy modeling technique and the linear modeling approach. © 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Pourghasemi H.R.,Tarbiat Modares University | Mohammady M.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia
Catena | Year: 2012

Landslide susceptibility mapping is essential for land use planning and decision-making especially in the mountainous areas. The main objective of this study is to produce landslide susceptibility maps at Safarood basin, Iran using two statistical models such as an index of entropy and conditional probability and to compare the obtained results. At the first stage, landslide locations were identified in the study area by interpretation of aerial photographs and from field investigations. Of the 153 landslides identified, 105 (≈. 70%) locations were used for the landslide susceptibility maps, while the remaining 48 (≈. 30%) cases were used for the model validation. The landslide conditioning factors such as slope degree, slope aspect, altitude, lithology, distance to faults, distance to rivers, distance to roads, topographic wetness index (TWI), stream power index (SPI), slope-length (LS), land use, and plan curvature were extracted from the spatial database. Using these factors, landslide susceptibility and weights of each factor were analyzed by index of entropy and conditional probability models. Finally, the ROC (receiver operating characteristic) curves for landslide susceptibility maps were drawn and the areas under the curve (AUC) were calculated. The verification results showed that the index of entropy model (AUC. =. 86.08%) performed slightly better than conditional probability (AUC. =. 82.75%) model. The produced susceptibility maps can be useful for general land use planning in the Safarood basin, Iran. © 2012 Elsevier B.V.

Khatamian M.,University of Tabriz | Khandar A.A.,University of Tabriz | Divband B.,University of Tabriz | Haghighi M.,Sahand University of Technology | Ebrahimiasl S.,University Putra Malaysia
Journal of Molecular Catalysis A: Chemical | Year: 2012

Lanthanide doped ZnO nanoparticles with different Ln (Ln = La, Nd and Sm) contents were synthesized by polymer pyrolysis method and characterized by various techniques such as XRD, UV-vis, SEM, TGA, and TEM. The XRD results revealed that Ln 3+ is uniformly dispersed on ZnO nanoparticles in the form of small Ln 2O 3 cluster. From SEM and TEM images it was found that the particle size of La-doped ZnO is much smaller as compared to that of pure ZnO. The photocatalytic activity of La-doped ZnO in the degradation of 4-nitrophenol (4-NP) was studied. The effects of the type and amount of loadings on the photocatalytic activity of Ln-doped ZnO were studied and the results were compared with pure ZnO. It was observed that the rate of degradation of 4-NP over Ln-doped ZnO increases with increasing La, Nd and Sm loading up to 4, 4 and 8 wt% and then decreases. It was found that the doping of Ln in ZnO helps to achieve complete mineralization of 4-NP within a short irradiation time. Among the catalysts, the 4 wt% Nd-doped ZnO was the most active and showing high photocatalytic activity for the degradation of 4-NP. © 2012 Elsevier B.V.

Lim C.T.S.,University Putra Malaysia
Indian Journal of Pharmacology | Year: 2016

Oral sodium phosphate (OSP), an effective bowel purgative, is available over the counter (OTC) and requires a substantially lower volume than polyethylene glycol-based preparative agents. Rarely, OSP consumption has been associated with acute hypocalcemia and hyperphosphatemia. We describe a case of chronic kidney disease patient developing symptomatic hypocalcemia following OTC OSP. © 2016 Indian Journal of Pharmacology Published by Wolters Kluwer - Medknow.

Akgun A.,Middle East Technical University | Sezer E.A.,Hacettepe University | Nefeslioglu H.A.,General Directorate of Mineral Research and Exploration | Gokceoglu C.,Hacettepe University | Pradhan B.,University Putra Malaysia
Computers and Geosciences | Year: 2012

In this study, landslide susceptibility mapping using a completely expert opinion-based approach was applied for the Sinop (northern Turkey) region and its close vicinity. For this purpose, an easy-to-use program, "MamLand," was developed for the construction of a Mamdani fuzzy inference system and employed in MATLAB. Using this newly developed program, it is possible to construct a landslide susceptibility map based on expert opinion. In this study, seven conditioning parameters characterising topographical, geological, and environmental conditions were included in the FIS. A landslide inventory dataset including 351 landslide locations was obtained for the study area. After completing the data production stage of the study, the data were processed using a soft computing approach, i.e., a Mamdani-type fuzzy inference system. In this system, only landslide conditioning data were assessed, and landslide inventory data were not included in the assessment approach. Thus, a file depicting the landslide susceptibility degrees for the study area was produced using the Mamdani FIS. These degrees were then exported into a GIS environment, and a landslide susceptibility map was produced and assessed in point of statistical interpretation. For this purpose, the obtained landslide susceptibility map and the landslide inventory data were compared, and an area under curve (AUC) obtained from receiver operating characteristics (ROC) assessment was carried out. From this assessment, the AUC value was found to be 0.855, indicating that this landslide susceptibility map, which was produced in a data-independent manner, was successful. © 2011 Elsevier Ltd.

Ho L.-W.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2016

In recent years, the Malaysian government has attempted to develop renewable energy (RE) through newly introduced regulatory supports after 30 years of failure to achieve a greater than one percent non-hydroelectric RE share in the total power mix. The government is currently assessing the onshore wind energy potential in Malaysia to determine the possibility of including wind energy in its FiT scheme. However, wind energy development in this low-energy location is not as straightforward as it would seem. Many previous wind studies in Malaysia have relied on poor data and simplistic or inadequate methodologies, resulting in grossly inaccurate estimates of wind potential. Moreover, two wind turbine generator demonstration projects executed by the government have failed. However, above all, the greatest factor impairing the progress of RE development in Malaysia is the weak and uncertain political support of these efforts. This lack of robust support is particularly true where fossil fuels are still heavily subsidised amid the subsidy reform in 2013. A review of global wind energy development shows that successful projects depend heavily on a sound and robust regulatory framework supported by strong and consistent political will. This dependence is not observed in Malaysia, where the government continues to subsidise private independent fossil fuel power producers but levies taxes on electricity consumers to fund RE development. These levies do not effectively support RE development, given the magnitude of the RE fund compared to fossil fuel subsidies. In the absence of strong and sincere political will, the progress of RE development in Malaysia has been notably slow. As a result, the prospect of wind energy development in Malaysia currently remains vague. This paper discusses the above issues in detail and recommends selected regulatory mechanisms based on the global experience of supporting RE development in Malaysia. © 2015 Elsevier Ltd. All rights reserved.

Wei C.C.,University Putra Malaysia
Proceedings - 2014 International Symposium on Biometrics and Security Technologies, ISBAST 2014 | Year: 2015

The evolution of an information technology has been expended and growth rapidly since last decade, especially in the era of an internet web technology, such as, e-commence, ebusiness or e-payment or e-shopping and more. The evolution of an internet web technology has made the transmission of the data or information over the web is more comprehensive. Thus, the data or information is easy to hack, crack or spy by the unauthorized persons over the network. This paper proposed a technique of cryptography to make the data or information to be more secure during transmission over the internet technology based on the DNA Stenography with the Finite State Machine (Mealy Machine) theory. This proposed algorithm is able to securing the data or information at least 3 levels of combinations for the password conversion. © 2014 IEEE.

Jordehi A.R.,University Putra Malaysia | Joorabian M.,Shahid Chamran University
2011 5th International Power Engineering and Optimization Conference, PEOCO 2011 - Program and Abstracts | Year: 2011

In this paper, Evolution Strategies (ES) is used to find optimal placement of FACTS devices in power systems. The goal of optimization is to maximize the system loadability. Optimization is based on finding locations and settings of FACTS devices. Simulations are implemented on IEEE 30-bus test system. From different types of FACTS devices, SVC, TCSC and UPFC are used in this research. The results show that using FACTS devices, the loadability of power system increases significantly. It also shows that there exists a maximum number of devices beyond which, the loadability of power system can not be increased. The implementation results of the method are promising and encouraging, so it is a good method for implementation on the FACTS optimization problem. © 2011 IEEE.

A split plot 3 × 3 experiment was designed to examine the impact of three concentrations of CO 2 (400, 800 and 1,200 μmol·mol -1) on the phenolic and flavonoid compound profiles, phenylalanine ammonia lyase (PAL) and antioxidant activity in three varieties of Labisia pumila Benth. (var. alata, pumila and lanceolata) after 15 weeks of exposure. HPLC analysis revealed a strong influence of increased CO 2 concentration on the modification of phenolic and flavonoid profiles, whose intensity depended on the interaction between CO 2 levels and L. pumila varieties. Gallic acid and quercetin were the most abundant phenolics and flavonoids commonly present in all the varieties. With elevated CO 2 (1,200 μmol·mol -1) exposure, gallic acid increased tremendously, especially in var. alata and pumila (101-111%), whilst a large quercetin increase was noted in var. lanceolata (260%), followed closely by alata (201%). Kaempferol, although detected under ambient CO 2 conditions, was undetected in all varieties after exposure. Instead, caffeic acid was enhanced tremendously in var. alata (338~1,100%) and pumila (298~433%). Meanwhile, pyragallol and rutin were only seen in var. alata (810 μg·g -1 DW) and pumila (25 μg·g -1 DW), respectively, under ambient conditions; but the former compound went undetected in all varieties while rutin continued to increase by 262% after CO 2 enrichment. Interestingly, naringenin that was present in all varieties under ambient conditions went undetected under enrichment, except for var. pumila where it was enhanced by 1,100%. PAL activity, DPPH and FRAP also increased with increasing CO 2 levels implying the possible improvement of health-promoting quality of Malaysian L. pumila under high CO 2 enrichment conditions.

Taheri S.,University Putra Malaysia
Genetics and molecular research : GMR | Year: 2012

The genus Curcuma is a member of the ginger family (Zingiberaceae) that has recently become popular for use as flowering pot plants, both indoors and as patio and landscape plants. We used PCR-based molecular markers (ISSRs) to assess genetic variation and relationships between five varieties of curcuma (Curcuma alismatifolia) cultivated in Malaysia. Sixteen ISSR primers generated 139 amplified fragments, of which 77% had high polymorphism among these varieties. These markers were used to estimate genetic similarity among the varieties using Jaccard's similarity coefficient. The similarity matrix was used to construct a dendrogram, and a principal component plot was developed to examine genetic relationships among varieties. Similarity coefficient values ranged from 0.40 to 0.58 (with a mean of 0.5) among the five varieties. The mean value of number of observed alleles, number of effective alleles, mean Nei's gene diversity, and Shannon's information index were 8.69, 1.48, 0.29, and 0.43, respectively.

Sung C.T.B.,University Putra Malaysia
Pertanika Journal of Tropical Agricultural Science | Year: 2012

This study was carried out to determine the distribution of organic matter and its constituents, as well as other soil properties, in various aggregate size fractions for four soil types in Malaysia, and to investigate the relationship and relative importance of these soil properties on aggregate stability. The four soil series with contrasting particle size distributions used were Munchong (Typic Hapludox), Melaka (Xanthic Hapludox), Rengam (Typic Paleudult), and Bungor (Typic Paleudult). The top soil, i.e. 0-15 cm of the soils of the four soil series was sampled and analyzed for their particle size distribution, aggregation, aggregate stability, organic matter, humic acids (HA), fulvic acids (FA), polysaccharides, functional groups of HA and FA (carboxylic, COOH, and phenolic-OH), and free Fe and Al oxides. Multiple linear regression revealed that silt, followed by free Fe oxides, fine sand, FA-OH, and HA-COOH, were the most important soil constituents to explain the observed differences in the aggregate stability between the four soil types. Generally, as the aggregate size decreased, the amount of clay, silt, OM, and free Fe oxides would also increase, while the aggregation and the amount of sand would decrease. As for the Rengam and Bungor series, the aggregate stability would generally increase with the decreasing aggregate size. Meanwhile, the observed differences in the amounts of HA, FA, and polysaccharides were mainly due to the differences in the soil types. © Universiti Putra Malaysia Press.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
Journal of the Franklin Institute | Year: 2013

The steady two-dimensional stagnation point flow toward a stretching/shrinking sheet with the bottom surface of the sheet heated by convection from a hot fluid is considered. The governing partial differential equations are transformed into ordinary differential equations, before being solved numerically. Results for the skin friction coefficient and the local Nusselt number as well as the temperature profiles are presented for different values of the governing parameters. Effects of the governing parameters on the heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. © 2013 The Franklin Institute.

Teh C.B.S.,University Putra Malaysia
Journal of Agricultural Science and Technology | Year: 2012

Aggregate stability is an important soil property because it dictates how strongly a soil can resist water erosion. The objectives in this study were: (1) to compare the stability of six soil aggregate size fractions, primarily to determine if aggregate stability varies with aggregate size, and (2) to determine with which aggregate size fraction the stability of most soils would be different from one another. Eight soils classified as Ultisols and Oxisols and from varying land uses, of different textures and overall acceptable aggregate stability were sampled and each separated into six aggregate size fractions of: 5-8, 3-5, 2-3, 1-2, 0.5-1, and 0.25-0.5 mm. Aggregate stability of whole soils and of individual aggregate size fractions were determined through wet-sieving, using nested sieves. It was shown that: (1) the kind of relationship between soil aggregate stability and aggregate size depended on both factors of soil type and individual aggregate size; (2) the stability of any two soil aggregate size fractions would become progressively less linearly related as the differences in aggregate size became more pronounced; (3) for the same soil, the stability of the large aggregate size fractions of > 0.5 mm were significantly different from that of the small aggregate size fractions of 0.25-0.5 mm; and (4) the differences in aggregate stability among whole soils were due more to the differences in the stability of the soil aggregate sizes larger than 3 mm. The study revealed that for Ultisol and Oxisol soils, it was not necessary to measure the stability of individual aggregate size fractions. Instead, the stability of a single aggregate size fraction could be used to represent the macroaggregate stability of whole soils.

Jordehi A.R.,University Putra Malaysia
Applied Soft Computing Journal | Year: 2015

Particle swarm optimisation (PSO) is a well-established optimisation algorithm inspired from flocking behaviour of birds. The big problem in PSO is that it suffers from premature convergence, that is, in complex optimisation problems, it may easily get trapped in local optima. In this paper, a new PSO variant, named as enhanced leader PSO (ELPSO), is proposed for mitigating premature convergence problem. ELPSO is mainly based on a five-staged successive mutation strategy which is applied to swarm leader at each iteration. The experimental results confirm that in all terms of accuracy, scalability and convergence rate, ELPSO performs well. © 2014 Elsevier B.V. All rights reserved.

Rohman A.,Gadjah Mada University | Man Y.B.C.,University Putra Malaysia
Chemometrics and Intelligent Laboratory Systems | Year: 2012

Among eleven studied vegetable oils, rice bran oil (RBO) has the close similarity to extra virgin olive oil (EVOO) in terms of FTIR spectra, as shown in the score plot of first and second principal components. The peak intensities at 18 frequency regions were used as matrix variables in principal component analysis (PCA). Consequently, the presence of RBO in EVOO is difficult to detect. This study aimed to use the chemometrics approach, namely discriminant analysis (DA) and multivariate calibrations of partial least square and principle component regression to analyze RBO in EVOO. DA was used for the classification of EVOO and EVOO mixed with RBO. Multivariate calibrations were exploited for the quantification of RBO in EVOO. The combined frequency regions of 1200-900 and 3020-3000cm -1 were used for such analysis. The results showed that no misclassification was reported for the classification of EVOO and EVOO mixed with RBO. Partial least square regression either using normal or first derivative FTIR spectra can be successfully used for the quantification of RBO in EVOO. In addition, analysis of fatty acid composition can complement the results obtained from FTIR spectral data. © 2011 Elsevier B.V.

Al-Saidi N.M.G.,University of Technology, Iraq | Said M.R.M.,University Putra Malaysia
European Physical Journal: Special Topics | Year: 2014

Biometric identification protocol has been received an increasing interest recently. It is a process that determines person identity by making use of their biometric features. A new biometric identification method is presented in this paper based on partial self-similarity that used to identify features within fingerprint images. This approach is already used in Fractal Image Compression (FIC) due to their ability to represent the images by a limited number of affine transformations, and its variation of scale, translation or rotation. These features give the recognition process high impact and good performance. To process data in a fingerprint image, it first converted into digital format using Optical Fingerprint Reader (OFR). The verification process is done by comparing these data with the server data. The system analysis shows that the proposed method is efficient in terms of memory and time complexity. © 2014 EDP Sciences and Springer.

Djauhari M.A.,University Putra Malaysia | Gan S.L.,University of Technology Malaysia
Physica A: Statistical Mechanics and its Applications | Year: 2015

Since its introduction fifteen years ago, minimal spanning tree has become an indispensible tool in econophysics. It is to filter the important economic information contained in a complex system of financial markets' commodities. Here we show that, in general, that tool is not optimal in terms of topological properties. Consequently, the economic interpretation of the filtered information might be misleading. To overcome that non-optimality problem, a set of criteria and a selection procedure of an optimal minimal spanning tree will be developed. By using New York Stock Exchange data, the advantages of the proposed method will be illustrated in terms of the power-law of degree distribution. © 2014 Elsevier B.V. All rights reserved.

Kazemilari M.,University of Technology Malaysia | Djauhari M.A.,University Putra Malaysia
Physica A: Statistical Mechanics and its Applications | Year: 2015

This paper shows how the concept of vector correlation can appropriately measure the similarity among multivariate time series in stocks network. The motivation of this paper is (i) to apply the RV coefficient to define the network among stocks where each of them is represented by a multivariate time series; (ii) to analyze that network in terms of topological structure of the stocks of all minimum spanning trees, and (iii) to compare the network topology between univariate correlation based on r and multivariate correlation network based on RV coefficient. ©2015 Elsevier B.V. All rights reserved.

Zakaria R.,University Putra Malaysia | Harvey A.P.,Newcastle University
Fuel Processing Technology | Year: 2012

Biodiesel is a fuel derived from renewable resources such as edible and inedible oil-bearing seed, algae, and waste cooking oil. The conventional biodiesel process involves oil extraction, refining and transesterification. Alternatively, transesterification can actually be performed directly from the oil-bearing materials without prior extraction. This route which is often termed reactive extraction or in situ transesterification has the advantages of simplifying the biodiesel production process as well as potentially reducing production cost. In this study, the reactive extraction of rapeseed with methanol has been characterised. The effects of process parameters on the yield, conversion and reaction rate differ substantially from conventional transesterification due to the dependence on both extraction and reaction. The rate of ester formation is mainly affected by the catalyst concentration, temperature and particle size while the equilibrium yield largely depends on the solvent to oil molar ratio. A high yield of ester (> 85%) can only be achieved at high solvent to oil molar ratios (> 475:1). Parametric studies and light microscope images of reactively extracted seed suggested that reactive extraction occurs by transesterification of the oil inside the seed, followed by diffusion of the products into the bulk solvent. © 2012 Elsevier B.V.

Ooi C.P.,University Putra Malaysia
Cochrane database of systematic reviews (Online) | Year: 2012

Momordica charantia (bitter gourd) is not only a nutritious vegetable but it is also used in traditional medical practices to treat type 2 diabetes mellitus. Experimental studies with animals and humans suggested that the vegetable has a possible role in glycaemic control. To assess the effects of mormodica charantia for type 2 diabetes mellitus. Several electronic databases were searched, among these were The Cochrane Library (Issue 1, 2012), MEDLINE, EMBASE, CINAHL, SIGLE and LILACS (all up to February 2012), combined with handsearches. No language restriction was used. We included randomised controlled trials (RCTs) that compared momordica charantia with placebo or a control intervention, with or without pharmacological or non-pharmacological interventions. Two authors independently extracted data. Risk of bias of the trials was evaluated using the parameters of randomisation, allocation concealment, blinding, completeness of outcome data, selective reporting and other potential sources of bias. A meta-analysis was not performed given the quality of data and the variability of preparations of momordica charantia used in the interventions (no similar preparation was tested twice). Four randomised controlled trials with up to three months duration and investigating 479 participants met the inclusion criteria. Risk of bias of these trials (only two studies were published as a full peer-reviewed publication) was generally high. Two RCTs compared the effects of preparations from different parts of the momordica charantia plant with placebo on glycaemic control in type 2 diabetes mellitus. There was no statistically significant difference in the glycaemic control with momordica charantia preparations compared to placebo. When momordica charantia was compared to metformin or glibenclamide, there was also no significant change in reliable parameters of glycaemic control. No serious adverse effects were reported in any trial. No trial investigated death from any cause, morbidity, health-related quality of life or costs. There is insufficient evidence on the effects of momordica charantia for type 2 diabetes mellitus. Further studies are therefore required to address the issues of standardization and the quality control of preparations. For medical nutritional therapy, further observational trials evaluating the effects of momordica charantia are needed before RCTs are established to guide any recommendations in clinical practice.

Yusoff Z.M.,University Putra Malaysia | Ngwenya B.T.,University of Edinburgh | Parsons I.,University of Edinburgh
Chemical Geology | Year: 2013

In this study we describe the mobility and fractionation of REEs in two deep (up to 30m) tropical weathering profiles developed on two granites from the Kuala Lumpur pluton, Malaysia, sampled at Cheras and Rawang. On the basis of Na2O and K2O both are S-type granites, but Rawang has higher CaO, MgO and FeO than Cheras and lower SiO2. With respect to Al-saturation Rawang is I-type and Cheras is S-type. We compared the two profiles in terms of total REEs, magnitude and changes in Ce and Eu anomalies, REE mobility and LREE/HREE fractionation. Rawang profiles have higher REE contents, display lower mobility for most except the heaviest REEs and show higher LREE/HREE fractionation than those from Cheras. These differences can be linked to differences in primary mineralogy and degree of weathering, the latter controlling the type and volume of secondary minerals. Specifically, bowl-shaped parent-rock-normalised patterns in the Cheras saprolites appear to be a result of apatite dissolution. Moreover, moderate weathering evident in lower Mineralogical Indices of Alteration (MIA) at Cheras has conserved parent rock REE patterns and fractionation factors in the saprolites. By contrast, more intense weathering observed in Rawang profiles has produced abundant kaolinite group minerals that have preferentially retained LREE, which consequently display high LREE/HREE fractionation. This study provides important insights into the factors controlling REE mobility during tropical weathering, and its potential as an indicator of weathering intensity. © 2013 Elsevier B.V.

Esfandiari E.,Islamic Azad University at Majlesi | Mariun N.B.,University Putra Malaysia
IEEE Transactions on Industrial Electronics | Year: 2013

This paper provides experimental results for a 2.5-kW 47-level prototype of the switch-ladder multilevel inverter including the following: input and output voltage and current waveforms under resistive and inductive loads, efficiency, total harmonic distortion, voltage stresses across the switches, behavior of the system under fault condition, and no-load power dissipation. The most important advantage of this inverter is that only four switches conduct in each interval in low frequency. This matter, beside the elimination of switching losses, has made this inverter an efficient choice with 97% peak efficiency. The ability to continue working with open-circuit modules is another advantage of the inverter. Furthermore, some important factors behind the unreliability and inefficiency of inverters have been improved, including the following: low duty cycle of conducting switches, staircase voltage stresses across switches with low-voltage steppes, line switching frequency results in low temperature of switches, possibility of removing low-pass filters, and independence to capacitors. The inverter is proposed to be an advantageous choice in low-voltage stand-alone photovoltaic applications. © 1982-2012 IEEE.

The World Health Organization confirmed that the novel influenza A, H1N1 as a pandemic on 11 June 2009. After less than three months, 182 countries were affected by the pandemic accounting for about 150,000 infected cases and 3000 mortality. Successful H1N1 pandemic management strategies' shaped by making changes in health behavior. The aim of this study was to document patients' knowledge, attitudes and practices (KAP) regarding the pandemic influenza A (H1N1) and its prevention. We performed a cross-sectional study on knowledge, attitudes and practices (KAP) on preventive measures of Influenza A (H1N1) involving 322 patients attending Klinik Kesihatan Jinjang, a primary health care clinic in Kuala Lumpur, Malaysia from May 10 to 26, 2010 using a face to face interview with a structured pre-tested questionnaire. The majority of the respondents were females (56.8%), Malays (43.2%) aged between 18-27 years old (28.9%). There were significant association between knowledge on the complication of H1N1, effectiveness of the treatment, preventive measures of Influenza A (H1N1) and race (p<0.001) and educational level (p<0.001). There were also significant associations between attitude scores of these patients and their gender (p=0.03), and educational level (p=0.001). Practice scores related to H1N1 were found to be significantly associated with race (p<0.001) and educational level (p<0.001). The significant associations were observed between knowledge and attitude (p<0.001), knowledge and practices (p<0.001), as well as attitude and practices related to H1N1 (p<0.001). Knowledge has a crucial effect on patients' attitude and practice particularly in a pandemic spread. So health policy makers should attempt to disseminate information about preventive measures to community in order to improve their preventive practices during pandemics.

Azianty S.,University Technology of MARA | Yahya A.K.,University Technology of MARA | Halimah M.K.,University Putra Malaysia
Journal of Non-Crystalline Solids | Year: 2012

Ternary tellurite glasses with the chemical formula 80TeO 2-(2 - x)ZnO-xFe 2O 3 (x = 0-15 mol%) have been prepared by the melt-quenching method. Elastic and structural properties of the glasses were investigated by measuring both longitudinal and shear velocities using the pulse-echo overlap method at 5 MHz and Fourier transform infrared (FTIR) spectroscopy, respectively. Both longitudinal and shear velocity showed a large increase of 3.40% and 4.68%, respectively, at x = 5 mol% before a smaller increase for x > 5 mol%. Interestingly, longitudinal modulus (L), shear modulus (G), bulk modulus (K) and Young's modulus (E) recorded similar trends with increase in Fe 2O 3. The initial large increases in shear and longitudinal velocity and related elastic moduli observed at x = 5 mol% are suggested to be due to structural modification which enhances rigidity of the glass network. FTIR analysis showed increase in bridging oxygen (BO) as indicated by the relative intensity of the TeO 4 assigned peaks and increase in intensity of the FeO 6 assigned peak (∼ 451 cm - 1) which indicates that Fe acts as a modifier in the glass network. The increase in rigidity of the glass system is suggested to be due to the increase of BO together with the formation of strong covalent FeO bond. Quantitative analysis based on the bulk compression and ring deformation models showed that the k bc/k exp value decreased gradually from 2.41 (x = 0 mol%) to 2.02 (x = 15 mol%) which infers that the glass system became a relatively more open 3D network as Fe 2O 3 was increased. © 2012 Elsevier B.V. All rights reserved.

Sarmadi V.H.,University Putra Malaysia
The Medical journal of Malaysia | Year: 2010

We have previously shown that mesenchymal stem cells (MSC) inhibit tumour cell proliferation, thus promising a novel therapy for treating cancers. In this study, MSC were generated from human bone marrow samples and characterised based on standard immunophenotyping. When MSC were co-cultured with BV173 and Jurkat tumour cells, the proliferation of tumour cells were profoundly inhibited in a dose dependent manner mainly via cell to cell contact interaction. Further cell cycle analysis reveals that MSC arrest tumour cell proliferation in G0/G1 phase of cell cycle thus preventing the entry of tumour cells into S phase of cell cycle.

Rezaee Jordehi A.,University Putra Malaysia
Applied Soft Computing Journal | Year: 2015

Bat swarm optimisation (BSO) is a novel heuristic optimisation algorithm that is being used for solving different global optimisation problems. The paramount problem in BSO is that it severely suffers from premature convergence problem, that is, BSO is easily trapped in local optima. In this paper, chaotic-based strategies are incorporated into BSO to mitigate this problem. Ergodicity and non-repetitious nature of chaotic functions can diversify the bats and mitigate premature convergence problem. Eleven different chaotic map functions along with various chaotic BSO strategies are investigated experimentally and the best one is chosen as the suitable chaotic strategy for BSO. The results of applying the proposed chaotic BSO to different benchmark functions vividly show that premature convergence problem has been mitigated efficiently. Actually, chaotic-based BSO significantly outperforms conventional BSO, cuckoo search optimisation (CSO), big bang-big crunch algorithm (BBBC), gravitational search algorithm (GSA) and genetic algorithm (GA). © 2014 Elsevier B.V. All rights reserved.

Tan L.K.,University of Malaya | Ooi P.T.,University Putra Malaysia | Thong K.L.,University of Malaya
Food Control | Year: 2013

The aim of this study was to determine the prevalence of Yersinia enterocolitica and its bioserotypes from food and pigs in Malaysia. Fifty-eight raw porcine (raw pork meat, internal organs and other parts) and 48 non-porcine food (raw beef, poultry products, seafood, vegetables, tofu, and pasteurised milk) from wet markets located in Kuala Lumpur, Selangor, Perak, and Pahang were examined for the presence of Y.enterocolitica. Specimens (nasal, oral and rectal swabs) from 165 pigs (from nine farms) located at central and northern parts of Malaysia were also collected for Y.enterocolitica detection. Presumptive isolates were characterised biochemically and further confirmed by PCR. Out of 58 raw porcine food, Y.enterocolitica was detected in 7 (12.1%) samples in which raw pork meat (whole meat) had the highest prevalence 5/21 (23.8%), followed by raw pork liver 1/5 (20.0%) and raw pork intestine 1/8 (12.5%). No Y.enterocolitica was isolated from the 48 non-porcine foods. Overall, two pathogenic (bioserotypes 3 variant/O:3 and 1B/O:8) and one non-pathogenic (bioserotype 1A/O:5) Y.enterocolitica strains were isolated from food. Out of 165 pigs examined, 3 (1.8%) pigs were carriers for Y.enterocolitica. All 3 pigs were asymptomatic grower pigs from Penang, carried Y.enterocolitica bioserotype 3 variant/O:3. Post-enrichment PCR approach gave a higher prevalence, 60.3%, 41.7% and 27.9% for porcine food, non-porcine food and pigs, respectively. Both pathogenic and non-pathogenic Y.enterocolitica were present in our domestic pigs and food. Improper food handling and processing may cause cross contamination of this pathogen to humans, affirms a potential risk for public health. © 2013 Elsevier Ltd.

Ooi C.P.,University Putra Malaysia
Cochrane database of systematic reviews (Online) | Year: 2012

Colesevelam is a second-generation bile acid sequestrant that has effects on both blood glucose and lipid levels. It provides a promising approach to glycaemic and lipid control simultaneously. To assess the effects of colesevelam for type 2 diabetes mellitus. Several electronic databases were searched, among these The Cochrane Library (Issue 1, 2012), MEDLINE, EMBASE, CINAHL, LILACS, OpenGrey and Proquest Dissertations and Theses database (all up to January 2012), combined with handsearches. No language restriction was used. We included randomised controlled trials (RCTs) that compared colesevelam with or without other oral hypoglycaemic agents with a placebo or a control intervention with or without oral hypoglycaemic agents. Two review authors independently selected the trials and extracted the data. We evaluated risk of bias of trials using the parameters of randomisation, allocation concealment, blinding, completeness of outcome data, selective reporting and other potential sources of bias. Six RCTs ranging from 8 to 26 weeks investigating 1450 participants met the inclusion criteria. Overall, the risk of bias of these trials was unclear or high. All RCTs compared the effects of colesevelam with or without other antidiabetic drug treatments with placebo only (one study) or combined with antidiabetic drug treatments. Colesevelam with add-on antidiabetic agents demonstrated a statistically significant reduction in fasting blood glucose with a mean difference (MD) of -15 mg/dL (95% confidence interval (CI) -22 to - 8), P < 0.0001; 1075 participants, 4 trials, no trial with low risk of bias in all domains. There was also a reduction in glycosylated haemoglobin A1c (HbA1c) in favour of colesevelam (MD -0.5% (95% CI -0.6 to -0.4), P < 0.00001; 1315 participants, 5 trials, no trial with low risk of bias in all domains. However, the single trial comparing colesevelam to placebo only (33 participants) did not reveal a statistically significant difference between the two arms - in fact, in both arms HbA1c increased. Colesevelam with add-on antidiabetic agents demonstrated a statistical significant reduction in low-density lipoprotein (LDL)-cholesterol with a MD of -13 mg/dL (95% CI -17 to - 9), P < 0.00001; 886 participants, 4 trials, no trial with low risk of bias in all domains. Non-severe hypoglycaemic episodes were infrequently observed. No other serious adverse effects were reported. There was no documentation of complications of the disease, morbidity, mortality, health-related quality of life and costs. Colesevelam added on to antidiabetic agents showed significant effects on glycaemic control. However, there is a limited number of studies with the different colesevelam/antidiabetic agent combinations. More information on the benefit-risk ratio of colesevelam treatment is necessary to assess the long-term effects, particularly in the management of cardiovascular risks as well as the reduction in micro- and macrovascular complications of type 2 diabetes mellitus. Furthermore, long-term data on health-related quality of life and all-cause mortality also need to be investigated.

Sarbini S.R.,University Putra Malaysia | Kolida S.,University of Reading | Gibson G.R.,University of Reading | Rastall R.A.,University of Reading
British Journal of Nutrition | Year: 2013

The fermentation selectivity of a commercial source of α-gluco- oligosaccharides (BioEcolians; Solabia) was investigated in vitro. Fermentation by faecal bacteria from four lean and four obese healthy adults was determined in anaerobic, pH-controlled faecal batch cultures. Inulin was used as a positive prebiotic control. Samples were obtained at 0, 10, 24 and 36 h for bacterial enumeration by fluorescent in situ hybridisation and SCFA analyses. Gas production during fermentation was investigated in non-pH-controlled batch cultures. α-Gluco-oligosaccharides significantly increased the Bifidobacterium sp. population compared with the control. Other bacterial groups enumerated were unaffected with the exception of an increase in the Bacteroides-Prevotella group and a decrease in Faecalibacterium prausnitzii on both α-gluco-oligosaccharides and inulin compared with baseline. An increase in acetate and propionate was seen on both substrates. The fermentation of α-gluco-oligosaccharides produced less total gas at a more gradual rate of production than inulin. Generally, substrates fermented with the obese microbiota produced similar results to the lean fermentation regarding bacteriology and metabolic activity. No significant difference at baseline (0 h) was detected between the lean and obese individuals in any of the faecal bacterial groups studied. Copyright © 2012 The Authors.

Abbasalipourkabir R.,Hamadan University of Medical Sciences | Salehzadeh A.,Hamadan University of Medical Sciences | Abdullah R.,University Putra Malaysia
Biotechnology | Year: 2011

Recently more focus has been put to the development of innovative drug-delivery systems that includes liposomes and solid lipid nanoparticles (SLNs). An in vitro study was conducted to determine the effect of solid lipid nanoparticle on the human breast cancer cell lines (MCF-7 and MDA-MB231). The SLNs based on palm oil were prepared using the high pressure homogenization method and were characterized by the particle size and polydispersity index (particle sizer), zeta potential (zetasizer), ultrastructure [transmission electron microscopy (TEM)] and MTT assay and natural red assay. Homogenization of solid lipid nanoparticles at 1000 bar for 20 cycles produced particles with 145.00±3.39 nm in size and zeta potential of-19.50±l .80 mv. The SLNs were generally round and uniform in shape. The cytotoxicity of the components of the SLN formulation was low: SLN with 1 % oleyl alcohol displayed no significant cytotoxicity effect on breast cancer cells. In the light of these findings, SLN stabilized with 30% lecithin and 1% oleyl alcohol as nonionic co-surfactant in aqueous phase was found to be safe for cells and the acceptable for the incorporation hpophihc drugs. © 2011 Asian Network for Scientific Information.

Khataee H.R.,University Putra Malaysia | Ibrahim M.Y.,Monash University
IET Nanobiotechnology | Year: 2012

Kinesin is a protein-based natural nanomotor that transports molecular cargoes within cells by walking along microtubules. Kinesin nanomotor is considered as a bio-nanoagent which is able to sense the cell through its sensors (i.e. its heads and tail), make the decision internally and perform actions on the cell through its actuator (i.e. its motor domain). The study maps the agent-based architectural model of internal decision-making process of kinesin nanomotor to a machine language using an automata algorithm. The applied automata algorithm receives the internal agent-based architectural model of kinesin nanomotor as a deterministic finite automaton (DFA) model and generates a regular machine language. The generated regular machine language was acceptable by the architectural DFA model of the nanomotor and also in good agreement with its natural behaviour. The internal agent-based architectural model of kinesin nanomotor indicates the degree of autonomy and intelligence of the nanomotor interactions with its cell. Thus, our developed regular machine language can model the degree of autonomy and intelligence of kinesin nanomotor interactions with its cell as a language. Modelling of internal architectures of autonomous and intelligent bio-nanosystems as machine languages can lay the foundation towards the concept of bio-nanoswarms and next phases of the bio-nanorobotic systems development. © 2012 The Institution of Engineering and Technology.

Tamjidyamcholo A.,University of Malaya | Bin Baba M.S.,University of Malaya | Tamjid H.,University Putra Malaysia | Gholipour R.,University of Tehran
Computers and Education | Year: 2013

Knowledge sharing is an important component of knowledge management systems. Security knowledge sharing substantially reduces risk and investment in information security. Despite the importance of information security, little research based on knowledge sharing has focused on the security profession. Therefore, this study analyses key factors, containing attitude, self-efficacy, trust, norm of reciprocity, and shared language, in respect of the information security workers intention to share knowledge. Information security professionals in virtual communities, including the Information Security Professional Association (ISPA), Information Systems Security Association (ISSA), Society of Information Risk Analysts (SIRA), and LinkedIn security groups, were surveyed to test the proposed research model. Confirmatory factor analysis (CFA) and the structural equation modelling (SEM) technique were used to analyse the data and evaluate the research model. The results showed that the research model fit the data well and the structural model suggests a strong relationship between attitude, trust, and norms of reciprocity to knowledge sharing intention. Hypotheses regarding the influence of self-efficacy and reciprocity, to knowledge sharing attitude were upheld. Shared language did not influence either the attitude or intention to share knowledge. © 2013 Elsevier Ltd. All rights reserved.

Jalaluddin I.,University Putra Malaysia
International Journal of Applied Linguistics and English Literature | Year: 2014

Learners form their self-efficacy beliefs by interpreting information primarily from four sources namely performance accomplishments, vicarious experiences, verbal persuasion, and emotional arousal. It is important to recognize the four cognitive nature of self-efficacy because the cognitive appraisal of information from the four sources will influence self-efficacy and it cannot be evaluated based on one source per se (Lane, Jones & Stevens 2002). This article explores the four sources of self-efficacy among the high achievers in writing course. In analysing the finding, Z-scores were derived from each self-efficacy component score based on the aggregate mean and the standard deviation of the class. Findings show high frequency of negative z-value reported for Specific Progress (SPR) and Social Feedback (SF). Meanwhile, high frequency of positive z-value is found in the General Progress (GPR) and Physiological States (PS) components. Based on the finding, pedagogical implications, limitations and directions for further research are presented. © Australian International Academic Centre.

Hussin H.,University Putra Malaysia
International Journal of Applied Linguistics and English Literature | Year: 2014

Graduate students furthering their studies at Master level are mature adult learners who bring with them a myriad of educational backgrounds and professional experiences into their studies. Delivering knowledge and information to them the traditional way via the lecture method per se may not be very effective anymore. They need methods that can utilize and make relevant their existing knowledge and professional experiences to help them realize their full potentials. This paper discusses the incorporation of four methods (individual presentation, dialogue, article critiquing and forum) into a graduate-level course (ESL Methodology) to supplement the lecture method, to provide variation in methods of teaching graduate students and as alternative measures for these graduate students to maximize their learning experience. © Australian International Academic Centre, Australia.

Yeganeh Ghotbi M.,University of Malayer | Bin Hussein M.Z.,University Putra Malaysia
Journal of Physics and Chemistry of Solids | Year: 2010

A new organic-clay material, in which the organic moiety is intercalated into the inorganic interlayer, was prepared using gallate anion (GA) as a guest, and Zn-Al-layered double hydroxide, as clay host. The ion-exchange technique was found to be effective for the intercalation process in the formation of the compound. Although the basal spacings of the LDH and its intercalated product were fairly similar, FTIR, CHNS and TGA/DTG results indicated that the GA was actually intercalated into the interlayer of the host in parallel orientation. The resulting nanostructure material possessed a well ordered layered structure with 42.2% GA loading (w/w). The release of the anion from the interlayer of the intercalated compound was found to be of controlled manner, governed by the first order kinetic and it was also concentration dependent. The material has potential as a nano-storage of anticarcenogenic agent with controlled delivery capability. © 2010 Elsevier Ltd. All rights reserved.

Syam S.,University Putra Malaysia | Abdelwahab S.I.,University of Malaya | Al-Mamary M.A.,Al Baha University | Mohan S.,University of Malaya
Molecules | Year: 2012

Several chalcones were synthesized and their in vitro cytotoxicity against various human cell lines, including human breast adenocarcinoma cell line MCF-7, human lung adenocarcinoma cell line A549, human prostate cancer cell line PC3, human adenocarcinoma cell line HT-29 (colorectal cancer) and human normal liver cell line WRL-68 was evaluated. Most of the compounds being active cytotoxic agents, four of them with minimal IC 50 values were chosen and studied in detail with MCF-7 cells. The compounds 1, 5, 23, and 25 were capable in eliciting apoptosis in MCF-7 cells as shown by multiparameter cytotoxicity assay and caspase-3/7, -8, and -9 activities (p < 0.05). The ROS level showed 1.3-fold increase (p < 0.05) at the low concentrations used and thus it was concluded that the compounds increased the ROS level eventually leading to apoptosis in MCF-7 cells through intrinsic as well as extrinsic pathways. © 2012 by the authors.

Jokar M.,Islamic Azad University at Damghan | Abdul Rahman R.,University Putra Malaysia
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2014

Colloidal silver nanoparticles were prepared via chemical reduction using polyethylene glycol (PEG) as a reducing agent, stabiliser and solvent. Silver polyethylene nanocomposites were produced via two methods, namely: melt blending and layer-by-layer (LBL) deposition of silver nanoparticles onto a polyethylene film. The silver ion release from either melt-blended or LBL-deposited nanocomposites into a food simulant and apple juice during 30 days at 4°C and 40°C was determined by atomic absorption spectroscopy. The effects of incorporating or coating of silver nanoparticles, silver concentration, contact media, temperature and time on silver ion migration were evaluated using factorial design. The diffusion coefficients of silver ions into the food simulants and apple juice were calculated using the Miltz model. The results indicated that the production method of nanocomposite, silver concentration, temperature, time and contact media showed a significant effect (p < 0.05) on silver ion migration. The quantity of silver ion migration from the nanocomposites into the food simulants and apple juice was less than the cytotoxicity-level concentration (10 mg kg-1) in all cases over 30 days. The coating of silver nanoparticles, higher silver concentration in the nanocomposite, higher temperature and acidic property of contact liquid all promoted the silver ion release from the nanocomposite films. The migration of silver ions from nanocomposites obeyed first-order diffusion kinetics. © 2014 Taylor & Francis.

Nouri H.,Islamic Azad University at Sanandaj Branch | Hong T.S.,University Putra Malaysia
Journal of Manufacturing Systems | Year: 2012

The cellular manufacturing system (CMS) is considered as an efficient production strategy for batch type production. The CMS relies on the principle of grouping machines into machine cells and grouping machine parts into part families based on pertinent similarity measures. The bacteria foraging algorithm (BFA) is a new in development computation technique extracted from the social foraging behavior of Escherichia coli (E. coli) bacteria. Ever since Kevin M. Passino invented the BFA, one of the main challenges has been employment of the algorithm to problem areas other than those for which the algorithm was proposed. This research work inquires the first applications of this emerging novel optimization algorithm to the cell formation (CF) problem. In addition, a newly developed BFA-based optimization algorithm for CF is discussed. In this paper, an attempt is made to solve the cell formation problem meanwhile taking into consideration number of voids in cells and a number of exceptional elements based on operational time of the parts required for processing in the machines. The BFA is suggested to create machine cells and part families. The performance of the proposed algorithm is compared with a number of algorithms that are most commonly used and reported in the corresponding scientific literature such as similarity coefficients methods (SCM), rank order clustering (ROC), ZODIAC, GRAFICS, MST, GATSP, GP, K-harmonic clustering (KHM), K-means clustering, C-link clustering, modified ART1, GA (genetic algorithm), evolutionary algorithm (EA), and simulated annealing (SA) using defined performance measures known as modified grouping efficiency and grouping efficacy. The results lie in favor of better performance of the proposed algorithm. © 2012 The Society of Manufacturing Engineers.

Banerjee S.,University Putra Malaysia | Mukhopadhyay S.,University of Calgary | Rondoni L.,Polytechnic University of Turin | Rondoni L.,National Institute of Nuclear Physics, Italy
Optics and Lasers in Engineering | Year: 2012

A new technique of transmitting encrypted combinations of gray scaled and chromatic images using chaotic lasers derived from MaxwellBlochs equations has been proposed. This novel scheme utilizes the general method of solution of a set of linear equations to transmit similar sized heterogeneous images which are a combination of monochrome and chromatic images. The chaos encrypted gray scaled images are concatenated along the three color planes resulting in color images. These are then transmitted over a secure channel along with a cover image which is an iris scan. The entire cryptology is augmented with an iris-based authentication scheme. The secret messages are retrieved once the authentication is successful. The objective of our work is briefly outlined as (a) the biometric information is the iris which is encrypted before transmission, (b) the iris is used for personal identification and verifying for message integrity, (c) the information is transmitted securely which are colored images resulting from a combination of gray images, (d) each of the images transmitted are encrypted through chaos based cryptography, (e) these encrypted multiple images are then coupled with the iris through linear combination of images before being communicated over the network. The several layers of encryption together with the ergodicity and randomness of chaos render enough confusion and diffusion properties which guarantee a fool-proof approach in achieving secure communication as demonstrated by exhaustive statistical methods. The result is vital from the perspective of opening a fundamental new dimension in multiplexing and simultaneous transmission of several monochromatic and chromatic images along with biometry based authentication and cryptography. © 2012 Elsevier Ltd. All rights reserved.

Tey Y.S.,University of Adelaide | Tey Y.S.,University Putra Malaysia | Brindal M.,University of Adelaide
Precision Agriculture | Year: 2012

Increasing pressure for food security and sustainability as well as a need to halt environmental degradation has focused attention on increasing the efficient use of farm resources. One answer to aspects of that problem is the use of precision agricultural technologies (PATs). To facilitate their adoption, initiatives have been fostered in developed countries since the 1980s. Despite a low rate of adoption elsewhere, similar efforts in recent years have been initiated in developing countries. Given this, understanding those underlying factors that influence the adoption of PATs is vital. It is timely to review these factors and to draw policy implications from that review for future actions. This review, based on studies investigating the limited adoption of PATs in 'experienced' countries, extrapolates their findings to explain why farmers have or have not adopted PATs. At the same time, this review summarizes the key insights for more effectively targeting 'new' followers: e. g. it provides some answers to the question of who is more likely to adopt PATs. Additionally, the review points to the limitations of current research in the area and suggests a robust economic model or multidisciplinary approach be adopted for future investigation. © 2012 Springer Science+Business Media, LLC.

Khoo H.E.,University Putra Malaysia
Molecules (Basel, Switzerland) | Year: 2012

Solid phase extraction (SPE) using Sep-Pak® cartridges is one of the techniques used for fractionation of antioxidant compounds in waste of dabai oil extraction (defatted dabai parts). The aim of this study was to determine the phenolic compounds and antioxidant capacity in crude extracts and several SPE fractions from methanolic extract of defatted dabai pulp and peel. Based on SPE, Sep-Pak® cyanopropyl and C18 cartridges were used to fractionate the antioxidant-rich crude extracts into water and methanolic fractions. Analyzed using LC-MS, flavonoids, anthocyanins, saponin derivatives and other unknown antioxidative compounds were detected in the defatted dabai crude extracts and their SPE fractions. Anthocyanins were the major phenolic compounds identified in the defatted dabai peel and detected in most of the SPE fractions. Methanolic fractions of defatted dabai parts embraced higher total phenolics and antioxidant capacity than water fractions. This finding also revealed the crude extracts of defatted dabai peel have the most significant antioxidant properties compared to the methanolic and water fractions studied. The crude extract of defatted dabai parts remain as the most potent antioxidant as it contains mixture of flavonoids, anthocyanins and other potential antioxidants.

Islam M.S.,University Malaysia Sarawak | Hamdan S.,University Malaysia Sarawak | Talib Z.A.,University Putra Malaysia | Ahmed A.S.,University Malaysia Sarawak | Rahman M.R.,University Malaysia Sarawak
Composites Science and Technology | Year: 2012

In this study, wood polymer nanocomposites (WPNCS) were manufactured from five Malaysian tropical wood species by vacuum-impregnation attended by in situ polymerization using phenol-formaldehyde resin and montmorillomite nanoclay. Percentage weight gain and density of wood polymer nanocomposites depended on wood species. Thermo-mechanical properties of wood samples were investigated by the dynamic mechanical thermal analysis (DMTA) over the temperature range of -100 °C to 200 °C. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases were also determined through DMTA test. Storage modulus (E') of WPNC samples exhibited significant improvement over the temperature range, in both glassy region and rubbery plateau in relation to their corresponding raw wood samples and wood polymer composites (WPCs). Furthermore, damping (loss tan δ) peaks of all wood species were lowered by PF-Nanoclay system treatment, an indication of improved surface interphase of wood. Dynamic Young's modulus (E d) of wood was also calculated using free-free vibration testing. A significant increment was obtained for the PF-Nanoclay impregnated WPNC samples. © 2012 Elsevier Ltd.

Yunus N.A.M.,University Putra Malaysia | Nili H.,University of Southampton | Green N.G.,University of Southampton
Electrophoresis | Year: 2013

Dielectrophoresis is the movement of particles in nonuniform electric fields and has been of interest for application to manipulation and separation at and below the microscale. This technique has the advantages of being noninvasive, nondestructive, and noncontact, with the movement of particle achieved by means of electric fields generated by miniaturized electrodes and microfluidic systems. Although the majority of applications have been above the microscale, there is increasing interest in application to colloidal particles around a micron and smaller. This paper begins with a review of colloidal and nanoscale dielectrophoresis with specific attention paid to separation applications. An innovative design of integrated microelectrode array and its application to flow-through, continuous separation of colloidal particles is then presented. The details of the angled chevron microelectrode array and the test microfluidic system are then discussed. The variation in device operation with applied signal voltage is presented and discussed in terms of separation efficiency, demonstrating 99.9% separation of a mixture of colloidal latex spheres. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Banerjee S.,University Putra Malaysia | Banerjee M.,Indian Institute of Technology Kanpur
Optics Communications | Year: 2012

The paper reports a detailed analysis of the chaotic dynamics of a theoretical model of a time delayed semi conductor laser. The periodic, quasi-periodic and chaotic nature is investigated with phase-plots, bifurcation analysis and lyapunov exponents. The effect of the system when induced by colored and bounded sine-Wiener noise has been examined extensively. The nature of the noise-induced propagating waves is investigated with the help of wavelet power spectra. It has been observed that the additive noise can suppress the chaotic dynamics of the system. Also the system is more chaotic in the presence of multiplicative noise. Moreover, the additive and multiplicative noise can modulate the output power upto a certain level, with constant input parameters. © 2011 Elsevier B.V. All rights reserved.

Khaw C.C.,University Tunku Abdul Rahman | Tan K.B.,University Putra Malaysia | Lee C.K.,Academic Science Malaysia | West A.R.,University of Sheffield
Journal of the European Ceramic Society | Year: 2012

The complete subsolidus phase diagram of the system Bi2O3-ZnO-Ta2O5, including cubic pyrochlore and monoclinic zirconolite phases, has been determined at 950-1050°C. Through systematic heat treatment and X-ray diffraction of over 100 compositions, the layout of compatibility triangles (both 2-phase and 3-phase) and single phase solid solution areas has been determined. Pyrochlore and zirconolite phases have ideal nominal compositions Bi1.5Zn1.0Ta1.5O7 and Bi2(Zn1/3Ta2/3)2O7 respectively, but both form solid solution areas. The sintering condition of pyrochlore pellets has been optimised to obtain high density ceramics with minimal weight loss: optimised condition is 1100°C for pellets covered with sacrificial powder. Permittivity, e{open}' dielectric loss and temperature coefficient of capacitance, TCC, of single phase materials were measured using impedance spectroscopy; e{open}' and TCC show little variation with composition but the losses are higher for Zn-deficient compositions. © 2011 Elsevier Ltd.

Amouzad Mahdiraji G.,University of Malaya | Abas A.F.,University Putra Malaysia
Optics Communications | Year: 2012

Performance optimization of 3 × 10 Gbps conventional electrical-duty-cycle division multiplexing (C-E-DCDM) technique is investigated. It is shown that controlling signal level spacing can optimize its performance. Two level spacing optimization techniques, one in electrical domain and another in optical domain are examined. In general, performance of the C-E-DCDM is improved significantly using both approaches. The results show by optimization, an improvement of around 5.5 dB can be achieved for the C-E-DCDM in terms of receiver sensitivity and optical signal-to-noise ratio using both electrical and optical methods. However, chromatic dispersion tolerance in one of the optimization approaches is degraded by around 34 ps/nm for negative dispersion, while the positive dispersion tolerance improved compared to the C-E-DCDM. © 2011 Elsevier B.V. All rights reserved.

Merriam S.,University of Georgia | Muhamad M.,University Putra Malaysia
Asian Pacific Journal of Cancer Prevention | Year: 2013

Background: For a number of reasons from cultural compatibility, to accessibility, to cost, traditional healers are a major source of health care in developing countries. In Malaysia, it's been estimated that upwards of 80% of the population consult traditional healers even if simultaneously seeking treatment from the Western medical system. Partially as a result of the widespread practice of visiting traditional healers, cancer diagnosis and treatment in Malaysia is often delayed or interrupted resulting in late presentation, advanced stage diagnosis, and a higher mortality rate than in Western countries. However, there is very little research on the role of traditional healers in cancer treatment in Malaysia. Materials and Methods: This qualitative study was designed to identify the roles traditional healers play in cancer diagnosis and treatment, with an eye to alleviating the cancer burden through educational responses with four publics in mind-policy makers, Western medical personnel, traditional healers, and the general public. In-depth interviews were conducted with 14 Malay traditional healers, 13 cancer survivors who had seen both traditional healers and Western doctors, and 12 cancer medical specialists. Results: Analysis of the data from these 39 participants revealed four roles traditional healers play in cancer treatment-medicinal healer, emotional comforter, spiritual guide, and palliative caregiver. Conclusions: Three roles (emotional, spiritual, palliative) can be seen as complementary to the allopathic system. Emotional and spiritual roles may augment the effectiveness of biomedical treatment. Cancer awareness and education programs need to position traditional healers as complementary, rather than an alternative to Western medical treatment; Validating the roles Traditional Healers can play in cancer treatment in MY through health promotion and education will contribute to alleviating the nation's cancer burden.

Rezaee Jordehi A.,University Putra Malaysia
Neural Computing and Applications | Year: 2015

Teaching–learning-based optimisation (TLBO) is an emerging gradient-free optimisation algorithm inspired by interactions between students and teacher in classrooms. TLBO has no control parameter to be tuned by user. This property makes it popular in research community. It has been successfully applied to challenging optimisation problems in different areas. In this study, TLBO is assisted to find optimal setting of thyristor-controlled series compensators in electric power systems. The experiments have been done for both N-1 and N-2 line outage contingencies. The results show that TLBO performs well in solving this problem. © 2014, The Natural Computing Applications Forum.

Abazari R.,Islamic Azad University at Ardabil | Kilicman A.,University Putra Malaysia
Neural Computing and Applications | Year: 2014

In this work, we applied the differential transform method, by presenting and proving some theorems, to solve the nonlinear integro-differential equation with proportional delays. This technique provides a sequence of functions which converges to the exact solution of the problem. In order to show the power and the robustness of the method and to illustrate the pertinent features of related theorems, some examples are presented. © 2012 Springer-Verlag London.

Joyce H.J.,University of Oxford | Wong-Leung J.,Australian National University | Yong C.-K.,University of Oxford | Docherty C.J.,University of Oxford | And 8 more authors.
Nano Letters | Year: 2012

Using transient terahertz photoconductivity measurements, we have made noncontact, room temperature measurements of the ultrafast charge carrier dynamics in InP nanowires. InP nanowires exhibited a very long photoconductivity lifetime of over 1 ns, and carrier lifetimes were remarkably insensitive to surface states despite the large nanowire surface area-to-volume ratio. An exceptionally low surface recombination velocity (170 cm/s) was recorded at room temperature. These results suggest that InP nanowires are prime candidates for optoelectronic devices, particularly photovoltaic devices, without the need for surface passivation. We found that the carrier mobility is not limited by nanowire diameter but is strongly limited by the presence of planar crystallographic defects such as stacking faults in these predominantly wurtzite nanowires. These findings show the great potential of very narrow InP nanowires for electronic devices but indicate that improvements in the crystallographic uniformity of InP nanowires will be critical for future nanowire device engineering. © 2012 American Chemical Society.

Sanei A.,Asian Leopard Specialist Society | Zakaria M.,University Putra Malaysia
Asia Life Sciences | Year: 2011

This study is a new attempt to identify the latest distribution pattern of the Persian leopard (Panthera pardus saxicolor Pocock 1927) in its entire range in Iran. Furthermore, the paper aimed to analyse the climatic factors in the current range of the leopard in the country. The study was performed in 138 sites (56 protected areas, 34 non-protected areas and 48 meteorology stations) throughout the country for a duration of four years starting in 2002 using rapid survey techniques and collection of secondary data. A total of 74 protected and non-protected areas are reported here as the leopard detection sites in the country. Although leopards have a wide distribution in Iran, results indicate that 69% of them are found in the northern part where a large tract of forests is regarded as one of the most important habitats for leopards in the country. In general, the leopards are mostly found in habitats with 0 to 20 days per year of ice cover and 58% of its identified range in the country have 3,100-3,600 sunny hours per annum. Leopards inhabit a wide range of temperature, i.e. from -23.10 to +49.40°C however, they are more often found in areas with temperature of 13 to 18°C. The majority (66%) of leopard distribution areas receive more than 200 mm of rain per year. Findings of this research would help the researchers in conducting further regional studies in the leopard distribution range described in this paper. It is also recommended that occupancy modeling on a regional scale should be conducted where leopards are present. © Rushing Water Publishers Ltd. 2011.

Farah R.N.,Sultan Idris University of Education | Othman M.,University Putra Malaysia
Applied Mathematics and Information Sciences | Year: 2014

The design of the interconnection network is one of the main research issues in distributed computing with regard to some specific parameters. This paper works on Modified Chordal Rings Degree Six (CHRm6) topology. Two broadcasting schemes for CHRm6 are proposed. The first scheme is for even source nodes and the second scheme is for odd source nodes. The proposed broadcasting schemes give upper and lower bound of broadcasting in CHRm6 depends on total number of nodes. We prove the lower bound on the broadcast time is d+2 where d is the diameter of the CHRm6. © 2014 NSP Natural Sciences Publishing Cor.

Narzullaev A.,University Putra Malaysia | Park Y.,Yeungnam University
AEU - International Journal of Electronics and Communications | Year: 2013

Fingerprinting is a popular technology for indoor WLAN based locating systems. Received signal strength information from different access points is used to estimate the location of mobile users. One of the drawbacks of fingerprinting algorithm is the extensive and time-consuming calibration (training) phase, during which the received signal strength measurements from nearby wireless access points are gathered at pre-defined reference spots and stored in a database to build a prior radio signal strength map of the region. In this manuscript, we present a new, precise and time efficient calibration algorithm that combines the reference data collection procedure with the path-loss prediction model. Our algorithm requires only a few samples to be measured in a given region, and thus significantly reduces the calibration time; the rest of the signal strength database is then estimated by using path-loss prediction model. We carefully evaluate the proposed algorithm through a real-world experiment. Field test results show that our new approach reduces the calibration time without harming the location accuracy of the locating system. © 2012 Elsevier GmbH.

Ishak A.,National University of Malaysia | Nazar R.,National University of Malaysia | Bachok N.,University Putra Malaysia | Pop I.,Technical University of Cluj Napoca
Physica A: Statistical Mechanics and its Applications | Year: 2010

The steady magnetohydrodynamic (MHD) mixed convection boundary layer flow of a viscous and electrically conducting fluid near the stagnation-point on a vertical permeable surface is investigated in this study. The velocity of the external flow and the temperature of the plate surface are assumed to vary linearly with the distance from the stagnation-point. The governing partial differential equations are first transformed into ordinary differential equations, before being solved numerically by a finite-difference method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. Both assisting and opposing flows are considered. It is found that dual solutions exist for both cases, and the range of the mixed convection parameter for which the solution exists increases with suction. © 2009 Elsevier B.V. All rights reserved.

Anarjan N.,Islamic Azad University at Tabriz | Tan C.P.,University Putra Malaysia
JAOCS, Journal of the American Oil Chemists' Society | Year: 2013

Astaxanthin, as a functional lipid, can be incorporated easily into different water-based food formulations in the form of a nanodispersion. In this study, astaxanthin nanodispersions were produced using different stabilizer systems, namely, polysorbate 20 (PS20), sodium caseinate (SC), gum arabic (GA) and an optimum combination of these three stabilizers (OPT). Since astaxanthin is sensitive to oxidative damage, its degradations kinetics in the prepared nanodispersion systems were investigated as a function of storage temperature, atmosphere and light. The results showed that astaxanthin degradation followed a first-order kinetic and, in most cases, astaxanthin was more stable in optimum-formulated three-component-stabilized nanodispersions as compared to nanodispersion systems stabilized by individual stabilizers. In addition, high storage temperature and intense illumination significantly (P < 0.05) increased the degradation of astaxanthin, while oxygen-free conditions significantly (P < 0.05) reduced the astaxanthin degradation rate. © 2013 AOCS.

Wong L.P.,University of Malaya | George E.,University Putra Malaysia | Tan J.-A.M.A.,University of Malaya
BMC Public Health | Year: 2011

Abstract. Background: Thalassaemia is a common public health problem in Malaysia and about 4.5 to 6% of the Malays and Chinese are carriers of this genetic disorder. The major forms of thalassaemia result in death in utero of affected foetuses (-thalassaemia) or life-long blood transfusions for survival in -thalassaemia. This study, the first nationwide population based survey of thalassaemia in Malaysia, aimed to determine differences in public awareness, perceptions and attitudes toward thalassaemia in the multi-racial population in Malaysia. Methods. A cross-sectional computer-assisted telephone interview survey of a representative sample of multi-racial Malaysians aged 18 years and above was conducted between July and December 2009. Results: Of a total of 3723 responding households, 2846 (76.4%) have heard of thalassaemia. Mean knowledge score was 11.85 (SD 4.03), out of a maximum of 21, with higher scores indicating better knowledge. Statistically significant differences (P < 0.05) in total knowledge score by age groups, education attainment, employment status, and average household income were observed. Although the majority expressed very positive attitudes toward screening for thalassaemia, only 13.6% of married participants interviewed have been screened for thalassaemia. The majority (63.4%) were unsupportive of selective termination of foetuses diagnosed with thalassaemia major. Conclusion: Study shows that carrier and premarital screening programs for thalassaemia may be more effective and culturally acceptable in the reduction of pregnancies with thalassaemia major. The findings provide insights into culturally congruent educational interventions to reach out diverse socio-demographic and ethnic communities to increase knowledge and cultivate positive attitudes toward prevention of thalassaemia. © 2011 Wong et al; licensee BioMed Central Ltd.

Mohammad N.,International Islamic University Malaysia | Alam Md.Z.,International Islamic University Malaysia | Kabbashi N.A.,International Islamic University Malaysia | Ahsan A.,University Putra Malaysia
Resources, Conservation and Recycling | Year: 2012

Palm oil production is a major agricultural industry in Malaysia, in which palm oil mill effluent (POME) and oil palm empty fruit bunch (EFB) are considered as major waste products from the palm oil industry. These waste products create an environmental hazard and entail high disposal costs every year. Composting is a biologically based process which is practiced to stabilize the organic matter for soil amendment (producing compost) and to protect the environment from the detrimental effects of these waste products. This study reviews the composting process of EFB and POME as a single substrate and/or their mixture by using potential filamentous fungi that are especially lignocellulolytic and antibiotic (in a matured stage) in nature within several effective parameters, for example, C/N ratio, moisture content, pH, temperature, etc. Several studies record the mature composting process as being 60 days. In most cases, temperature and moisture content was maintained up to 70°C and 60-75%, respectively. In addition, this study reviews EFB and POME with their constituents for an efficient composting process. © 2011 Elsevier B.V. All rights reserved.

Zahid N.,University of Nottingham Malaysia Campus | Ali A.,University of Nottingham Malaysia Campus | Siddiqui Y.,University Putra Malaysia | Maqbool M.,University of Nottingham Malaysia Campus
Postharvest Biology and Technology | Year: 2013

Significant (P≤ 0.05) differences were observed in dragon fruit quality when treated with different concentrations of ethanolic extract of propolis (EEP) (0.25, 0.50, 0.75 and 1.0%) and stored at 20 ± 2 °C and 80 ± 5% relative humidity (RH) for 20 days. Fruit treated with 0.50% EEP showed the most promising results, while fruit treated with 0.75 and 1.0% EEP showed some phytotoxic effects even after 8 days of storage. The results of gas exchange analysis also proved the efficacy of 0.50% EEP concentration. Thus, it can be concluded from the present investigation that EEP at 0.50% concentration could be used to extend the storage life of dragon fruit without any negative effects on the quality. © 2013 Elsevier B.V.

Rohman A.,Gadjah Mada University | Rohman A.,University of Technology Malaysia | Che Man Y.B.,University Putra Malaysia
International Journal of Food Properties | Year: 2013

Fourier transform infrared spectroscopy has been developed for rapid monitoring of the oxidative stabilities of selected vegetable oils, namely corn oil, rice bran oil, soybean oil, and sunflower oil during thermal treatment at 160°C for 120 h. There were several absorbance changes between non-oxidized and oxidized vegetable oils during thermal oxidation. Peak intensities at 3470, 1655, and 967 cm-1 were increased; meanwhile peak intensities at 3008 and 722 cm-1 were decreased. The R2 values for the correlation between the absorbance changes at 3008 cm-1 and the specific absorptivities of conjugated dienes for corn oil, rice bran oil, soybean oil, and sunflower oil were 0.938, 0.845, 0.978, and 0.824, respectively. The absorbance changes of Fourier transform infrared spectra at 3008 cm-1 were also correlated with the specific absorptivities of conjugated trienes and p-anisidine values with the acceptable R2 values. Compared with the conventional technique, the use of Fourier transform infrared spectroscopy for measurement the thermal oxidative stability has some advantages, i.e., it is a rapid technique and no sample preparation. In addition, Fourier transform infrared spectroscopy reduces or eliminates solvents and chemical reagents that are hazardous to human health or to the environment; therefore, Fourier transform infrared spectroscopy can support the campaign of "green analytical chemistry." © 2013 Copyright Taylor and Francis Group, LLC.

Ashurov R.,University Putra Malaysia
International Journal of Wavelets, Multiresolution and Information Processing | Year: 2011

The almost everywhere convergence of wavelets transforms of L p-functions under minimal conditions on wavelets is well known. But this result does not provide any information about the exceptional set (of Lebesgue measure zero), where convergence does not hold. In this paper, under slightly stronger conditions on wavelets, we prove convergence of wavelet transforms everywhere on the entire Lebesgue set of Lp-functions. On the other hand, practically all the wavelets, including Haar and "French hat" wavelets, used frequently in applications, satisfy our conditions. We also prove that the same conditions on wavelets guarantee the Riemann localization principle in L1 for the wavelet transforms. © 2011 World Scientific Publishing Company.

Gomes C.,University Putra Malaysia | Diego A.G.,Electric Research Institute of Mexico
Safety Science | Year: 2011

This paper provides comprehensive analysis on the lightning protection scenarios in 48 communication and broadcasting towers situated in similar isokeraunic contours in Sri Lanka at 79°-81° East and 5°-10° North. The investigation has been conducted to study the hazardous environment created on the tower and in the neighbourhood in the event of a lightning strike to the tower. The results show that a direct strike to an antenna structure in a metallic tower is rare irrespective of the presence of an air-termination or a down conductor. However, side flashing or arcing to antenna structures is highly possible once the air-termination and/or down conductor is installed and attempts are made to insulate the system from the tower. The outcome also shows that equipotential bonding of the grounding system, a distributed grounding network including a ring conductor and a suitable system of surge protective devices play a much vital role in lightning protection of equipment and safety of people compared to the effects of simply achieving a low grounding resistance. However, in the absence of such integrated, distributed and equipotentialized grounding system, a high value of ground resistance will sharply increase the possibility of accidents and damage. Considering the observations of the investigations into account we have designed a concrete embedded grounding system for tower sites at problematic locations. Finally, the scenarios for safety management at telecommunication tower sites have been discussed. © 2011 Elsevier Ltd.

Arai T.,University Putra Malaysia | Chino N.,University of Tokyo
Journal of Applied Ichthyology | Year: 2013

In order to understand the life history of the tropical freshwater eel Anguilla bicolor bicolor found in Malaysian natural waters, the timing of maturation was studied. Age at maturation of the species ranged from 4 to 6 years. The timing of maturation was similar to that of the temperate eel A. japonica, but earlier than that of other temperate eels A. anguilla, A. rostrata, A. australis and A. dieffenbachii, reported previously. The higher growth rate found in A. bicolor bicolor associated with the habitat environment might induce the differences in the maturation timing among species. © 2012 Blackwell Verlag GmbH.

Aziz M.A.A.,University of Technology Malaysia | Jalil A.A.,University of Technology Malaysia | Triwahyono S.,University of Technology Malaysia | Triwahyono S.,Ibnu Sina Institute for Fundamental Science Studies | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2014

Mesostructured silica nanoparticles (MSN) and Ni loaded onto MSN (Ni/MSN) for the methanation of CO2 were prepared by the sol-gel and impregnation methods. Catalytic testing was conducted in the temperature range of 423-723K under atmospheric pressure in the presence of H2. Ni supported on MSN was compared with others types of support such as MCM-41 (Mobile Crystalline Material), HY (protonated Y zeolite), SiO2 and γ-Al2O3. The activity of CO2 methanation followed the order: Ni/MSN>Ni/MCM-41>Ni/HY>Ni/SiO2>Ni/γ-Al2O3. The nitrogen physisorption and pyrrole adsorbed IR spectroscopy results indicated that the high activity of Ni/MSN is due to the presence of both intra- and inter-particle porosity which led to the high concentration of basic sites. In addition, the correlation between N-H band intensity and the turnover frequency revealed that the methanation activity increased with increasing of the concentration of basic sites. The presence of defect sites or oxygen vacancies in MSN was responsible for the formation of surface carbon species, while Ni sites dissociated hydrogen to form atomic hydrogen. The surface carbon species then interacted with atomic hydrogen to form methane. The Ni/MSN catalyst performed with good stability and no deactivation up to 200h. © 2013 Elsevier B.V.

Suleiman M.B.,University Putra Malaysia | Ishak F.,University Technology of MARA
Japan Journal of Industrial and Applied Mathematics | Year: 2010

This paper considers the numerical solution of delay differential equations. The predictor-corrector scheme based on generalized multistep methods are implemented in variable order variable stepsize techniques. The formulae are represented in divided difference form where the integration coefficients are computed by a simple recurrence relation. This representation produces simpler calculation as compared with the modified divided difference form, but no sacrifice is made in efficiency and accuracy of the method. Numerical results prove that the method is reliable, efficient and accurate. The P- and Q-stability regions for a fixed stepsize of the predictor-corrector scheme are illustrated for various orders. © 2010 The JJIAM Publishing Committee and Springer.

Kilicman A.,University Putra Malaysia | Eltayeb H.,King Saud University
Applied Mathematics and Information Sciences | Year: 2012

In this study we extend the classification of partial differential equations to the further using the convolutions products. The purpose of this study is to compute the solutions of some explicit initial-boundary value problems for one-dimensional wave equation with variable coefficients by means of Laplace transform which in general has no solution. © 2012 NSP Natural Sciences Publishing Cor.

Najigivi A.,Sharif University of Technology | Khaloo A.,Sharif University of Technology | Iraji Zad A.,Sharif University of Technology | Abdul Rashid S.,University Putra Malaysia
Composites Part B: Engineering | Year: 2013

The aim of this study was to assess the effects of two different types of SiO2 nanoparticles (N and M series) with different ratios on the workability and compressive strength of developed binary blended concretes cured in water and lime solution as two different curing media. N and M series SiO2 nanoparticles with an average size of 15 nm were used as obtained from the suppliers. Fresh and hardened concretes incorporating 0.5%, 1.0%, 1.5% and 2.0% of N and 2% of M series nanoparticles with constant water to binder ratio and aggregate content were made and tested. Fresh mixtures were tested for workability and hardened concretes were tested for compressive strength at 7, 28 and 90 days of curing. Fresh concrete test results showed that the workability of binary blends was reduced in the presence of both types of SiO2 nanoparticles. Hardened concrete test results revealed that the optimal replacement level of cement by N series of SiO2 nanoparticles for producing concrete with considerably improved strength was set at 1.0 wt.% after curing in water. However, the ultimate strengths of binary blended concretes were gained at 2.0 wt.% replacement of cement by both series after curing in lime solution. It is concluded that SiO2 nanoparticles play significant roles in mechanical properties of concrete by formation of additional calcium silicate hydrate gel during treatment, which played an important role in raising highly the compressive strength of binary blends. The current study sheds light on the implications of nanotechnology in nano-engineering of concrete. © 2013 Elsevier Ltd. All rights reserved.

Ibrahim R.,University Putra Malaysia | Pour Rahimian F.,University of Central Lancashire
Automation in Construction | Year: 2010

Communications for information synchronisation during the conceptual design phase usually require designers to employ more flexible and intuitive digital design tools. In developing such support tools, a case study research was initiated to first understand the current state of communication among novice design team members. The main purpose of the study is to understand the novice designers' collaboration culture when working on conceptual architectural design projects. The overall case study research involves 1) ethnography for data collection and 2) artefact and protocol analyses for data analysis. This paper presents the latter data analyses based on the earlier ethnography results about novice designers' conceptual design and technology design synthesis strategies. Data analyses on the characteristics of utilised external representation tools indicate that although conventional manual sketching is beneficial for providing rich intuitive design concepts, they have limitations when novice designers need to oversee complicated design problems. The study also found that although current conventional CAD tools are advantageous for detailed engineering design articulation, they do hinder novice designers' creativity due to their intuitive ideation limitation. Based on these results, this paper discusses the identified advantages and challenges of current design media and then proposes an alternative VR-based design interface for enhancing cognition and communication among designers during the conceptual design phase. © 2010 Elsevier B.V. All rights reserved.

Hassan S.,University Putra Malaysia
Journal of Computer Science | Year: 2012

Problem statement: In order to be able to manage its own information within its operating environment with minimal human intervention, a selfmanaging information system ought to identify and make use of information from the resources available in its environment. The development of requirements for selfmanaging information systems should start with an appropriate analysis model that can explicitly show the collaborating entities in the environment. The traditional forms of analysis in systems development approaches have not focused on computing systems environments and ways to identify environment resources. Approach: This study discusses the analysis activities in the development of selfmanaging information systems. Results: We propose an SSM based analysis model, which is able to examine the requirements for selfmanaging information systems. We describe the analysis of one particular system, the inventory management system and illustrate how this system fulfils certain desired selfmanaging properties. Conclusion: The SSM based analysis model is able to address the actuation capabilities of the systems and considers internal and external resources in the environment. The analysis model not only takes into account the information from the environment but is also able to provide support in determining the requirements for selfmanaging properties. © 2012 Science Publications.

Rezaee Jordehi A.,University Putra Malaysia
Neural Computing and Applications | Year: 2015

Artificial immune system algorithm (AIS) is a population-based global heuristic optimisation algorithm. It is inspired by immune system of human bodies. Alleviating premature convergence problem of heuristic optimisation algorithms is a hot research area. In this study, chaotic-based strategies are embedded into AIS to alleviate its premature convergence problem. Four various chaotic-based AIS strategies with five different chaotic map functions (totally 20 cases) are examined, and the best one is chosen as the best chaotic paradigm for AIS. The results of applying the proposed chaotic AIS to a variety of unimodal and multimodal benchmark functions reveal that it offers high-quality solutions. It significantly outperforms conventional AIS and gravitational search algorithm. The outperformance is both in terms of accuracy of solutions and stability in finding accurate solutions. © 2014, The Natural Computing Applications Forum.

Md Yunus N.A.,University Putra Malaysia | Green N.G.,University of Southampton
Microsystem Technologies | Year: 2010

We have developed a method of fabricating microfluidic device channels for bio-nanoelectronics system by using high performance epoxy based dry photopolymer films or dry film resists (DFRs). The DFR used was with a trademark name Ordyl SY355 from Elga Europe. The developing and exposing processes as well as the time taken in making the channels are recorded. Finally from those recorded methods, the accurate procedures and time taken for DFR development and exposure have been found and ultimately been consistently used in fabricating our channels. These channels were patterned and sandwiched in between two glass substrates. In our advance, the channel was formed for the colloidal particle separation system. They can be used for handling continuous fluid flow and particle repositioning maneuver using dielectrophoresis that have showed successful results in the separation. © 2010 Springer-Verlag.

Shahmohammadi M.S.,University Putra Malaysia | Keyhanian S.,University of Groningen
Applied Energy | Year: 2015

Malaysia has abundant potentials of renewable energy resources mainly because of its rich agriculture that makes high potential in bio-power and its tropical climate, which provides sufficient sunlight for utilization of solar systems. Feed in Tariff mechanism has been applied since 2011 in Malaysia to expand utilization of renewable energy for electricity generation. In this study, a broad range of data is gathered to develop a comprehensive system dynamics model to evaluate the impacts of Feed in Tariff mechanism on the generation mix of Malaysia during a 20-year period between 2011 and 2030. Results demonstrate that although the policy may lead to a satisfactory level of target achievement but the Malaysian government may face an increasing shortage in its RE fund budget starting around 2019 unless it increases its income sources by rising the surcharges on electricity bills or decreases its expenditures by optimizing the amount of FiT payments in different periods. The sensitivity analysis illustrates that the more funding will not lead to a more sustainable generation mix unless it is paid in the right time and in the right direction. Using this model, policymakers can carry out analysis to determine the amount of money that must be collected from the electricity consumers through the surcharges on electricity bills as well as the amount of feed in tariff to be paid for different renewable resources in different periods. © 2015 Elsevier Ltd.

Sazlina S.G.,University Putra Malaysia
Malaysian Family Physician | Year: 2015

The world population of older people is on the rise with improved health services. With longevity, older people are at increased risk of chronic non-communicable diseases (NCDs), which are also leading causes of death among older people. Screening through case finding in primary care would allow early identification of NCDs and its risk factors, which could lead to the reduction of related complications as well as mortality. However, direct evidence for screening older people is lacking and the decision to screen for diseases should be made based on comorbidity, functional status and life expectancy, and has to be individualised. © 2015, Academy of Family Physicians of Malaysia. All rights reserved.

Methylenetetrahydrofolate reductase (MTHFR) C677T is involved in folate and homocysteine metabolism. Disruption in the activity of this enzyme will alter their levels in the body. This study assessed MTHFR C677T polymorphism and its relationship with serum homocysteine and B-vitamins levels in a sample of Chinese and Malays subjects in UPM, Serdang. One hundred subjects were randomly selected from among the university population. Folate, vitamin B12, B6, and homocysteine levels were determined using MBA, ECLIA, and HPLC, respectively. PCR coupled with HinfI digestion was used for detection of MTHFR C677T polymorphism. The frequency of T allele was higher in the Chinese subjects (0.40) compared to the Malay (0.14). Folate, vitamin B12 and B6 levels were highest in the wild genotype in both ethnic groups. Subjects with heterozygous and homozygous genotype showed the highest homocysteine levels. The serum folate and homocysteine were mainly affected by homozygous genotype. MTHFR C677T polymorphism plays an important role in influencing the folate and homocysteine metabolism.

Yu Q.,University of Western Australia | Ahmad-Hamdani M.S.,University of Western Australia | Ahmad-Hamdani M.S.,University Putra Malaysia | Han H.,University of Western Australia | And 2 more authors.
Heredity | Year: 2013

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids. © 2013 Macmillan Publishers Limited All rights reserved.

Harith H.H.,University of New South Wales | Harith H.H.,University Putra Malaysia | Morris M.J.,University of New South Wales | Kavurma M.M.,University of New South Wales
Trends in Endocrinology and Metabolism | Year: 2013

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been extensively studied for its preferential ability to induce apoptosis of cancer cells. Beyond the cytotoxic capacity of TRAIL, new physiological and pathological roles for TRAIL have been identified, and there is now growing evidence supporting its involvement in the development of obesity and diabetes. This review summarizes the most recent findings associating TRAIL with obesity and diabetes in both humans and experimental settings. We also present and discuss some of the reported controversies behind TRAIL signaling and function. Understanding TRAIL mechanism(s) in vivo and its involvement in disease may lead to novel strategies to combat the growing pandemic of obesity and diabetes worldwide. © 2013.

Ibrahim M.H.,International Center for Education in Islamic Finance | Law S.H.,University Putra Malaysia
Habitat International | Year: 2014

The paper investigates the long run behavior of house prices and their dynamic interactions with bank credits, real output and interest rate for the case of Malaysia. Apart from the aggregate house prices, the analysis also covers various house price sub-indices, namely, the terraced house price index, the semi-detached house price index, the detached house price index and the high-rise price index. From the aggregate perspective, we note the presence of a long run relation among the variables. Moreover, the findings suggest the long run causality that runs from the included variables to both the aggregate house prices and bank credits. Dynamic interactions between house prices and bank credits are further reflected by the generated impulse-response functions. The disaggregate analysis indicates that only the terraced house price index forms a long run relation with bank credits, real output and interest rate with their dynamic interactions to mimic well the aggregate systems. Still, a further analysis reveals that shocks to the terraced house price tend to diffuse to other segments of housing markets. Among the housing types, the detached house price is relatively segmented and affected only indirectly through the diffusion/ripple effect. These findings bear important implications for macroeconomic stability, monetary policy and investment decisions. © 2013 Elsevier Ltd.

Elizabeth G.,University Putra Malaysia | Ann M.T.J.A.,University of Sfax
Medical Journal of Malaysia | Year: 2010

The haemoglobinopathies and thalassemias represent the most common inherited monogenic disorders in the world1. Beta-thalassaemia major is an ongoing public health problem in Malaysia2. Prior to 2004, the country had no national policy for screening and registry for thalassemia. In the absence of a national audit, the true figure of the extent of thalassemia in the Malaysian population was largely presumptive from micro-mapping studies from various research workers in the country. The estimated carrier rate for beta-thalassemia in Malaysia is 3.5-4%. There were 4768 transfusion dependent thalassemia major patients as of May 2010 (Data from National Thalassemia Registry).

Zakaria Z.A.,University Putra Malaysia
Canadian journal of physiology and pharmacology | Year: 2013

This study was carried out to determine the antinociceptive activity of a novel synthetic oxopyrrolidine-based compound, (2R,3R,4S)-ethyl 4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate (ASH21374), and to elucidate the involvement of the opioid, vanilloid, glutamate, and nitric oxide - cyclic guanosine monophosphate (NO/cGMP) systems in modulating the observed antinociception. ASH21374, in the doses of 2, 10, and 100 mg/kg body mass, was administered orally to mice 60 mins prior to exposure to various antinociceptive assays. From the results obtained, ASH21374 exhibited significant (P < 0.05) antinociceptive activity in the abdominal constriction, hot-plate, and formalin tests that was comparable with 100 mg/kg acetylsalicylic acid or 5 mg/kg morphine, respectively. ASH21374 also attenuated capsaicin- and glutamate-induced paw licking. Pre-treatment with 5 mg/kg naloxone significantly (P < 0.05) inhibited the activity in all assays, while pretreatment with 10 mg/kg β-funaltraxamine, 1 mg/kg naltrindole, or 1 mg/kg nor-binaltorphimine significantly (P < 0.05) reversed the activity in the abdominal constriction test. l-Arginine, N(G)-nitro-l-arginine methyl esters (l-NAME), methylene blue, and their combinations, failed to inhibit the ASH21374 antinociceptive activity. In conclusion, ASH21374 demonstrated antinociceptive activities on the peripheral and central nervous systems, mediated through the activation of opioid receptors, inhibition of the glutamatergic system, and attenuation of vanilloid-mediated nociceptive transmission. Further studies have been planned to determine the pharmacological potential of ASH21374.

Modarres Khiyabani F.,Islamic Azad University at Tabriz | Leong W.J.,University Putra Malaysia
Computers and Mathematics with Applications | Year: 2012

Quasi-Newton (QN) methods are generally held to be the most efficient minimization methods for solving unconstrained optimization problems. Among the QN methods, symmetric rank-one (SR1) is one of the very competitive formulas. In the present paper, we propose a new SR1 method. The new technique attempts to improve the quality of the SR1 Hessian by employing the scaling of the identity in a certain sense. However, since at some iterations these updates might be singular, indefinite or undefined, this paper proposes an updates criterion based on the eigenvalues of the SR1 update to measure this quality. Hence, the new method is employed only to improve the approximation of the SR1 Hessian. It is shown that the numerical results support the theoretical considerations for the usefulness of this criterion and show that the proposed method improves the performance of the SR1 update substantially. © 2012 Elsevier Ltd. All rights reserved.

Nouri H.,Islamic Azad University at Sanandaj Branch | Hong T.S.,University Putra Malaysia
Journal of Manufacturing Systems | Year: 2013

The cellular manufacturing system (CMS) is considered as an efficient production strategy for batch type production. The CMS relies on the principle of grouping machines into machine cells and grouping machine parts into part families on the basis of pertinent similarity measures. The bacteria foraging optimization (BFO) algorithm is a modern evolutionary computation technique derived from the social foraging behavior of Escherichia coli bacteria. Ever since Kevin M. Passino invented the BFO, one of the main challenges has been the employment of the algorithm to problem areas other than those of which the algorithm was proposed. This paper investigates the first applications of this emerging novel optimization algorithm to the cell formation (CF) problem. In addition, for this purpose matrix-based bacteria foraging optimization algorithm traced constraints handling (MBATCH) is developed. In this paper, an attempt is made to solve the cell formation problem while considering cell load variations and a number of exceptional elements. The BFO algorithm is used to create machine cells and part families. The performance of the proposed algorithm is compared with a number of algorithms that are most commonly used and reported in the corresponding scientific literature such as K-means clustering, the C-link clustering and genetic algorithm using a well-known performance measure that combined cell load variations and a number of exceptional elements. The results lie in favor of better performance of the proposed algorithm. © 2012 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.

Furtula V.,Environment Canada | Osachoff H.,Environment Canada | Derksen G.,Environment Canada | Juahir H.,University Putra Malaysia | And 2 more authors.
Water Research | Year: 2012

The effects of agricultural activities on stream water quality were assessed by nitrogen analysis, further investigated by gas chromatography mass spectrometry (GC-MS) sterol analysis (including chemometric analysis), and characterized by bacterial source tracking (BST). Surface water samples were collected from five sites, throughout the agriculturally-influenced Nathan Creek watershed, British Columbia, Canada and a nearby control site between October 2005 and March 2006. From a total of 48 samples, Canadian Water Quality Guidelines were exceeded nineteen times for nitrate (NO3-; guideline value: 2.94mg/L N) and four times for un-ionized ammonia (NH 3; guideline value 0.019mg/L N). Gas chromatography mass spectrometry single ion monitoring (GC-MS SIM) analysis of 18 sterols showed that five fecal sterols (coprostanol, episoprostanol, cholesterol, cholestanol, desmosterol) were detected at all sites except the control site (where only cholesterol, cholestanol and desmosterol were detected). Three phytosterols (campesterol, stigmasterol and β-sitosterol) were also detected at all sites while the hormone estrone was present at one site on two occasions at concentrations of 0.01 and 0.04μg/L. Chemometric analysis (principal component analysis and cluster analysis) grouped sites based on their similarities in sterol composition. Analysis of ten sterol ratios (seven for identifying human fecal contamination and four for differentiating sources of fecal contamination) showed multiple instances of human and animal contamination for every site but the control site. Application of a Bacteroides-BST method confirmed contamination from ruminant animals, pigs and dogs in varying combinations at all impact sites. Together, these results confirmed the impact of agricultural activities on the Nathan Creek watershed and support a need for better land management practices to protect water quality and aquatic life. © 2011.

Lee H.V.,University of Malaya | Taufiq-Yap Y.H.,University Putra Malaysia
Process Safety and Environmental Protection | Year: 2015

The focus of this study is to produce biodiesel using non-edible feedstock (Jatropha curcas oil) via heterogeneous base catalyzed transesterification reaction. The solid base catalysts, binary metal oxide (CaO-ZnO and CaO-La2O3) were selected for the transesterification of high acid jatropha oil. Furthermore, the design of experiments was performed using 5-level-4 factor central composite design coupled with response surface methodology (RSM) in order to optimize the transesterification conditions. Four process factors were evaluated: (1) reaction time (1-5 h), (2) methanol/oil molar ratio (15:1-30:1), (3) reaction temperature (40-200 °C) and (4) catalyst loading (1-5 wt.%). Based on the quadratic model generated from RSM, reaction temperature rendered the most significant effect for both CaO-ZnO and CaO-La2O3 catalyzed reactions, followed by catalyst loading and reaction time. Besides, both reaction models showed that interaction between reaction temperature with reaction time and catalyst loading has positively influenced the biodiesel yield. The highest conversion predicted for CaO-ZnO and CaO-La2O3 catalyzed reactions was 97.03% and 96.27%, respectively, with reasonable predictability and sufficient accuracy data (small error: 0.33-0.34%). Furthermore, the physicochemical characteristics of produced biodiesel were tested with compliance to ASTM D7851 and EN 14124. © 2014 The Institution of Chemical Engineers.

Mougouei D.,University Putra Malaysia
International Journal of Software Engineering and its Applications | Year: 2013

Large amount of security faults existing in software systems could be complex and hard to identify during the fault analysis. Therefore, it is not always possible to fully mitigate the internal or external security faults (vulnerabilities or threats) within the system. On the other hand, existence of faults in the system may eventually lead to a security failure. To avoid security failure of the target system it is required to make the system flexible and tolerant in the presence of security faults. This paper proposes a goal-based modeling approach to develop security requirements of Security-Critical Systems (SCSs) through explicitly factoring the faults into the requirement engineering process. Our approach establishes the Security Requirement Model (SRM) of the system based on its respective Security Fault Model (SFM). We incorporate fault tolerance into the SRM through considering the partial satisfaction of security goals. The proposed approach factors this partiality into the goals by using proper mitigation techniques during the refinement process. This approach eventually contributes to a fault tolerant model for security requirements of the target system ©2013 SERSC.

Teo T.,University of Auckland | Wong S.L.,University Putra Malaysia
Journal of Educational Computing Research | Year: 2013

This study explored the key drivers of student teachers' e-learning satisfaction. Three hundred and eighty-seven participants completed a survey questionnaire measuring their self-reported responses to six constructs (tutor quality, perceived usefulness, perceived ease of use, course delivery, facilitating conditions, and course satisfaction). Data analysis was performed using structural equation modeling. The results of this study showed that, apart from facilitating conditions, all constructs were significant predictors of e-learning satisfaction. However, facilitating conditions was found to be a significant mediator of perceived ease of use and satisfaction. Some implications for e-learning and teacher education were discussed. © 2013, Baywood Publishing Co., Inc.

The influence of human salivary enzymes on palm wines' odorant concentrations were investigated by the application of aroma extracts dilution analysis (AEDA) and by the calculation of odour activity values (OAVs), respectively. The odorants were quantified by means of stable isotope dilution assays (SIDA), and the degradation profiles of odorants by human saliva were also studied. Results revealed 46 odour-active compounds in the flavour dilution (FD) factor range of 4-256, and all were subsequently identified. Of the 46 odorants, 41 were identified in the Elaeis guineensis wine, 36 in Raphia hookeri wine and 29 in Borassus flabellifer wine. Among the odorants, the highest FD-factors were obtained from acetoin, 2-acetyl-1-pyrroline and 3-isobutyl-2- methoxypyrazine. Among the 13 potent odorants identified, five aroma compounds are reported here as important contributors to palm wine aroma, namely 3-isobutyl-2-methoxypyrazine, acetoin, 2-acetyl-1-pyrroline, 3-methylbutylacetate and ethyl hexanoate. Meanwhile, salivary enzymic degradation of odorants was more pronounced among the aldehydes, esters and thiols. © 1996-2013 MDPI AG.

Ahsan A.,University Putra Malaysia | Fukuhara T.,University of Fukui
Solar Energy | Year: 2010

In this paper, a new mass and heat transfer model of a Tubular Solar Still (TSS) was proposed incorporating various mass and heat transfer coefficients taking account of the humid air properties inside the still. The heat balance of the humid air and the mass balance of the water vapor in the humid air were formulized for the first time. As a result, the proposed model enabled to calculate the diurnal variations of the temperature, water vapor density and relative humidity of the humid air, and to predict the hourly condensation flux besides the temperatures of the water, cover and trough, and the hourly evaporation flux. The validity of the proposed model was verified using the field experimental results carried out in Fukui, Japan and Muscat, Oman in 2008. The diurnal variations of the calculated temperatures and water vapor densities had a good agreement with the observed ones. Furthermore, the proposed model can predict the daily and hourly production flux precisely. © 2010 Elsevier Ltd. All rights reserved.

Volatile compounds from roasted plantains (French sombre, AAB) and (Dwarf Kalapua, ABB) at different stages of ripening were evaluated by a gas chromatography-mass spectrometry (GC-MS) with headspace solid-phase microextraction (HS-SPME). A total of 42 volatile compounds were identified in the roasted plantain cultivars. Some of the volatile compounds with high concentration were 2,3-dimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine, (E)-2-hexenal, 2,5-dimethylpyrazine and 2,3-dihydro-5-hydroxyl-6-methyl-(4H)-pyran-4-on respectively. Principal component analysis (PCA) based on the relationships between ripening/quality of volatiles showed that 2-methyl propanol, furfural, 2,5-dimethyl pyrazine, 2,3-butanedione, guaiacol, 2-ethyl-3-methyl pyrazine, 5-, ethyl acetate, 2-pentanol, 3-isobutyl-2-methoxy pyrazine and 7,8-dihydro-β-ionol were considered to contribute significantly to the overall aroma quality of fairly riped (stages 4 and 5) and roasted plantains. © 2011 Elsevier Ltd.

Masdi H.,University Putra Malaysia | Mariun N.,National University of Malaysia
International Review of Electrical Engineering | Year: 2010

The study reported in this paper was aimed to investigate transient response of power transformer when lightning current pass through its winding. Analysis of distribution voltage at the winding taps was done, both by experimental and numerical simulation, by applying IEC-71 standard current surge (8/20 μs impulse current and 1.2/50 μs impulse voltage). Transformer's constants as: R, L, C were derived from the transformer construction, which consists of 9 winding layers at HV-side. The wave-shapes of the voltage across the winding sections were recorded. The response of the windings was then compared with results of a simulation using EMTDC/PSCAD. The simulation based on an RLC network model resulted in wave-shapes that are in good agreement to those of the experiment. Both results of the simulation and experiment show that the distribution of the impulse voltage across the windings is non linear, especially during the period of fraction of microseconds. Furthermore, results of the investigation show that a simple capacitance network model is sufficient for study of the impulse voltage distribution across transformer windings. © 2010 Praise Worthy Prize S.r.l.

Achenef M.B.,University of Gondar | Arifah A.K.,University Putra Malaysia
Academic Journal of Cancer Research | Year: 2012

Conjugated linoleic acids (CLAs) comprised of geometrical and positional isomers of octadecadienoic (18:2) acid with conjugated double bond system. They are found naturally in ruminant food products such as meat and milk because of the process of bacterial biohydrogenation and hydrolysis in the rumen. Studies have shown that CLAs have many health promoting properties. This study was conducted to assess and compare the cytotoxic effects, induction of apoptosis and cell cycle arrest by CLA isomers on human breast cancer cells (MCF7). Cells were grown on RPMI 1640 media and treated with different concentrations of cis-9, trans-11 (c9, t11), trans-10, cis-12 (t10, c12) and mixed isomers of CLA for 72 hours. The results were determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) cytotoxicity assay and terminal deoxynucleotide transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. The viability of MCF7 cancer cells was reduced significantly (P<0.05) by all CLA isomers used in a dose-dependent manner. The median inhibitory concentration (IC50) value varies with type of CLA isomer. t10, c12 was significantly 50 (P<0.05) more potent than c9, t11 CLA isomer. All CLA isomers induced significantly (P<0.05) higher proportion of apoptotic cells. It was also observed that significantly (P<0.05) higher proportion of cells in G0/1 but lower proportion in S and G2/M phases of the cell cycle in treated cells. These results suggested that CLA isomers 2 reduce the viability of MCF7 cancer cells which is associated with cell cycle arrest and induction of apoptosis. © IDOSI Publications, 2012.

Atangana A.,University of the Free State | Kilicman A.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

The standard version of acoustic wave equation is modified using the concept of the generalized Riemann-Liouville fractional order derivative. Some properties of the generalized Riemann-Liouville fractional derivative approximation are presented. Some theorems are generalized. The modified equation is approximately solved by using the variational iteration method and the Green function technique. The numerical simulation of solution of the modified equation gives a better prediction than the standard one. © 2013 Abdon Atangana and Adem Kiliçman.

Atangana A.,University of the Free State | Kilicman A.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

Fractional advection-dispersion equations are used in groundwater hydrology to model the transport of passive tracers carried by fluid flow in porous medium. A space-time fractional advection-dispersion equation (FADE) is a generalization of the classical ADE in which the first-order space derivative is replaced with Caputo or Riemann-Liouville derivative of order 0 < β ≤ 1, and the second-order space derivative is replaced with the Caputo or the Riemann-Liouville fractional derivative of order 1 < ≤ 2. We derive the solution of the new equation in terms of Mittag-Leffler functions using Laplace transfrom. Some examples are given. The results from comparison let no doubt that the FADE is better in prediction than ADE. © 2013 Abdon Atangana and Adem Kilicman.

Elbeleze A.A.,Universiti Sains Islam Malaysia | Kilicman A.,University Putra Malaysia | Taib B.M.,Universiti Sains Islam Malaysia
Mathematical Problems in Engineering | Year: 2013

The homotopy perturbation method, Sumudu transform, and He's polynomials are combined to obtain the solution of fractional Black-Scholes equation. The fractional derivative is considered in Caputo sense. Further, the same equation is solved by homotopy Laplace transform perturbation method. The results obtained by the two methods are in agreement. The approximate analytical solution of Black-Scholes is calculated in the form of a convergence power series with easily computable components. Some illustrative examples are presented to explain the efficiency and simplicity of the proposed method. © 2013 Asma Ali Elbeleze et al.

Klcman A.,University Putra Malaysia | Gadain H.E.,King Saud University
Journal of the Franklin Institute | Year: 2010

In this paper, we study the properties of Sumudu transform and relationship between Laplace and Sumudu transforms. Further, we also provide an example of the double Sumudu transform in order to solve the wave equation in one dimension which is having singularity at initial conditions. © 2010 The Franklin Institute.

Arafat H.A.,Masdar Institute of Science and Technology | Jijakli K.,Masdar Institute of Science and Technology | Ahsan A.,University Putra Malaysia
Journal of Cleaner Production | Year: 2015

In this study, the environmental impacts were assessed for five municipal solid waste (MSW) treatment processes with energy recovery potential. The life cycle assessment (LCA) tool was used to quantify the environmental impacts. The five processes considered are incineration, gasification, anaerobic digestion, bio-landfills, and composting. In addition, these processes were compared to recycling where applicable. In addition to environmental impacts quantification, the energy production potentials for the five processes were compared to provide a thorough assessment. To maximize the future applicability of our findings, the analyses were based on the waste treatment technologies as they apply to individual waste streams, but not for a specific MSW mixture at a particular location. Six MSW streams were considered; food, yard, plastic, paper, wood and textile wastes. From an energy recovery viewpoint, it was found that it is best to recycle paper, wood and plastics; to anaerobically digest food and yard wastes; and to incinerate textile waste. On the other hand, the level of environmental impact for each process depends on the considered impact category. Generally, anaerobic digestion and gasification were found to perform better environmentally than the other processes, while composting had the least environmental benefit. © 2013 Elsevier Ltd. All rights reserved.

Djojodihardjo H.,University Putra Malaysia | Djojodihardjo H.,Al - Azhar University of Indonesia
Acta Astronautica | Year: 2015

The application of BE-FE acoustic-structure interaction on a structure subject to acoustic load is elaborated using the boundary element-finite element acoustic structural coupling and the utilization of the computational scheme developed earlier. The plausibility of the numerical treatment is investigated and validated through application to generic cases. The analysis carried out in the work is intended to serve as a baseline in the analysis of acoustic structure interaction for lightweight structures. Results obtained thus far exhibit the robustness of the method developed. © 2014 IAA. Published by Elsevier Ltd. All rights reserved.

Ng W.L.,Kyushu University | Ng W.L.,University Putra Malaysia | Szmidt A.E.,Kyushu University
Aquatic Botany | Year: 2015

Natural hybridization is common in plants, including mangroves. Three Rhizophora mangrove species are recognized in the Indo-West Pacific region, namely R. apiculata, R. mucronata, and R. stylosa. So far, R. apiculata has been known to form sterile hybrid offspring with R. mucronata (= R. x annamalayana) and with R. stylosa (= R. x lamarckii). A third hybrid between morphologically similar R. mucronata and R. stylosa was only recently shown to exist, via DNA sequencing. However, it has been suspected that this newly discovered hybrid may be fertile, with potential to interbreed to give rise to advanced-generation hybrids in locations where both parental species occur. In this study, inter-simple sequence repeat (ISSR) markers were used to survey several stands where R. mucronata and R. stylosa co-occur. By screening through 26 ISSR primers, a set of species-specific diagnostic bands for each species were first identified from standard samples before being used to genotype the test samples. A chloroplast DNA locus was also sequenced in the test samples to determine the direction of hybridization. Results showed that hybridization occurred between R. mucronata and R. stylosa in all investigated locations with differing levels of introgression, and that it could happen in any direction. © 2014 Elsevier B.V.

Colorectal cancer (CRC) has long been associated with bacteremia and/or endocarditis by Streptococcus gallolyticus member bacteria (SGMB) but the direct colonization of SGMB along with its molecular carcinogenic role, if any, has not been investigated. We assessed the colonization of SGMB in CRC patients with history of bacteremia (CRC-w/bac) and without history of bacteremia (CRC-wo/bac) by isolating SGMB from feces, mucosal surfaces of colorectum, and colorectal tissues and detecting SGMB DNA, via PCR and in situ hybridization (ISH) assays targeting SodA gene in colorectal tissues. Moreover, mRNA of IL1, IL-8, COX-2, IFN-γ, c-Myc, and Bcl-2 in colorectal tissues of studied groups was assessed via ISH and RT-PCR. SGMB were found to be remarkably isolated in tumorous (TU) and non-tumorous (NTU) tissues of CRC-w/bac, 20.5% and 17.3%, and CRC-wo/bac, 12.8% and 11.5%, respectively while only 2% of control tissues revealed SGMB (P < 0.05); such contrast was not found in mucosal and fecal isolation of SGMB. The positive detection of SGMB DNA in TU and NTU of CRC-w/bac and CRC-wo/bac via PCR, 48.7%, 35.9%, 32.7%, and 23%, respectively, and ISH, 46.1%, 30.7%, 28.8%, and 17.3%, respectively, was higher than in control tissues, 4 and 2%, respectively (P < 0.05). SGMB count measured via quantitative PCR of SGMB DNA in terms of copy number (CN), in TU and NTU of CRC-w/bac and CRC-wo/bac, 2.96-4.72, 1.29-2.81, 2.16-2.92, and 0.67-2.07 log10 CN/g respectively, showed higher colonization in TU than in NTU and in CRC-w/bac than in CRC-wo/bac (P < 0.05). The PCR-based mRNA ratio and ISH-based percentage of positively stained cells of IL-1, 1.77 and 70.3%, COX-2, 1.63 and 44.8%, and IL-8, 1.73 and 70.3%, respectively, rather than IFN-γ, c-Myc, and Bcl-2, were higher in SGMB positive patients than in control or SGMB negative patients (P < 0.05). The current study indicated that colorectal cancer is remarkably associated with SGMB; moreover, molecular detection of SGMB in CRC was superior to link SGMB with CRC tumors highlighting a possible direct and active role of SGMB in CRC development through most probably inflammation-based sequel of tumor development or propagation via, but not limited to, IL-1, COX-2, and IL-8.

This paper provides a comprehensive guidance for the selection and installation of transient protection devices, especially in a TT wiring system with the aim of safeguarding both the equipment concerned and the operators and users of equipment. A number of core and fringe issues with respect to surge protection have been discussed in details with the view of developing high level of electrical safety practices among engineers. The information presented can also be used as educational material that guides electrical engineers in addressing lightning protection issues of LV power systems and ELV signal systems. A number of real life examples and survey outcomes that reflect misinterpretation of standards and scientific practices, gathered in the South Asian region have also been discussed. © 2011 Elsevier Ltd.

Kadem A.,Ferhat Abbas University Setif | Klman A.,University Putra Malaysia
Computers and Mathematics with Applications | Year: 2011

In this paper, the Chebyshev polynomials to solve analytically the fractional neutron transport equation in one-dimensional plane geometry are used. The procedure is based on the expansion of the angular flux in terms of the Chebyshev polynomials. The obtained system of fractional linear differential equation is solved analytically by using fractional Sumudu transform. © 2011 Elsevier Ltd. All rights reserved.

Shamsuri A.A.,National University of Malaysia | Shamsuri A.A.,University Putra Malaysia | Daik R.,National University of Malaysia
Materials | Year: 2013

An ionic liquid, 1-n-butyl-3-methylimidazolium chloride (BmimCl) was blended with urea at 1:1 mole ratio to create a BmimCl/Urea mixture. The agarose/talc composite films containing the BmimCl/Urea mixture were then acquired through a gelation method. The weight ratio of agarose and talc was fixed at 4:1, while the content of BmimCl/Urea was varied from 0 to 10 wt % relative to the overall weight of the composite films. The tensile stress and modulus results showed the optimum BmimCl/Urea content in the composite film lies at 8 wt %. The talc particles are embedded in the agarose matrix and there are no pullouts for the composite films containing BmimCl/Urea as demonstrated by SEM micrographs. The addition of BmimCl/Urea increased the glass transition temperature of the composite films, however, the thermal decomposition temperature decreased drastically. FTIR and FT-Raman spectra indicated the existence of interaction between agarose and talc, which improves their interfacial adhesion. As a conclusion, a BmimCl/Urea mixture can be utilized as a coupling agent for agarose/talc composite films. © 2013 by the authors.

Afsah-Hejri L.,University Putra Malaysia
International Food Research Journal | Year: 2013

Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world's pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.

Shameli K.,University Putra Malaysia
International journal of nanomedicine | Year: 2011

Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12-3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO(3). The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller-Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.

Mohammad M.,University of Selangor | Abdullah S.,National University of Malaysia | Jamaludin N.,National University of Malaysia | Innayatullah O.,University Putra Malaysia
Materials and Design | Year: 2014

This paper presents the capability of acoustic emission (AE) technique to predict the fatigue life of SAE 1045 carbon steel using a newly formulated statistical distribution. The specific AE parameters and the number of cycles to failure of the tested specimens were correlated using the Weibull distribution approach. The AE and strain signals were experimentally measured using the AE sensor and strain gauge respectively, with the sensors attached to the specimen during the cyclic test at several stress levels of constant amplitude loadings. The empirical model developed from the newly developed h- N curve, in correlation to the AE hits-number and cycles to failure, suggested that the AE technique has the potential to assess fatigue life for SAE 1045 carbon steel. Also, the validation results presented in the Weibull probability distribution technique are presented in the end of this paper. © 2013 Elsevier Ltd.

Zamiri R.,University Putra Malaysia
International journal of nanomedicine | Year: 2011

In the present work, we prepared silver nanoparticles by laser ablation of pure silver plate in ethanol and then irradiated the silver nanoparticles using a 532 nm Q-switched Nd:YAG pulsed laser. Transmission electron microscopic images of the sample after irradiation clearly showed formation of big structures, such as microrods and microbelts in ethanol. The obtained microbelts had a width of about 0.166 μm and a length of 1.472 μm. The reason for the formation of such a big structure is the tendency of the nanoparticles to aggregate in ethanol before irradiation, which causes fusion of the nanoparticles.

Rohman A.,Gadjah Mada University | Che Man Y.B.,University Putra Malaysia
The Scientific World Journal | Year: 2012

Commercially, extra virgin olive oil (EVOO) is subjected to be adulterated with low-price oils having similar color to EVOO. Fourier transform infrared (FTIR) spectroscopy combined with chemometrics has been successfully used for classification and quantification of corn (CO) and sunflower oils (SFOs) in EVOO sets. The combined frequency regions of 3027-3000, 1076-860, and 790-698 cm-1 were used for classification and quantification of CO in EVOO; meanwhile, SFO was analyzed using frequency regions of 3025-3000 and 1400-985 cm-1. Discriminant analysis can make classification of pure EVOO and EVOO adulterated with CO and SFO with no misclassification reported. The presence of CO in EVOO was determined with the aid of partial least square calibration using FTIR normal spectra. The calibration and validation errors obtained in CO's quantification are 0.404 and 1.13, respectively. Meanwhile, the first derivative FTIR spectra and PLS calibration model were preferred for quantification of SFO in EVOO with high coefficient of determination (R 2) and low errors, either in calibration or in validation sample sets. Copyright © 2012 Abdul Rohman and Y. B. Che Man.

Atiqah A.,International Islamic University Malaysia | Maleque M.A.,International Islamic University Malaysia |