Kuala Selangor, Malaysia

University of Selangor

www.unisel.edu.my
Kuala Selangor, Malaysia

The University of Selangor is a university wholly owned and managed by the Selangor state government independently without funding from the Malaysian federal government (and is thus regarded as a "private" university as opposed to a "public" university. It operates from two campuses in Selangor, Malaysia. Wikipedia.

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Prasad P.,University of Selangor | Ogawa S.,University of Selangor | Parhar I.S.,University of Selangor
Frontiers in Neuroscience | Year: 2015

The neuroendocrine mechanism regulates reproduction through the hypothalamo-pituitary gonadal (HPG) axis which is evolutionarily conserved in vertebrates. The HPG axis is regulated by a variety of internal as well as external factors. Serotonin, a monoamine neurotransmitter, is involved in a wide range of reproductive functions. In mammals, serotonin regulates sexual behaviours, gonadotropin release and gonadotropin-release hormone (GnRH) secretion. However, the serotonin system in teleost may play unique role in the control of reproduction as the mechanism of reproductive control in teleosts is not always the same as in the mammalian models. In fish, the serotonin system is also regulated by natural environmental factors as well as chemical substances. In particular, selective serotonin reuptake inhibitors (SSRIs) are commonly detected as pharmaceutical contaminants in the natural environment. Those factors may influence fish reproductive functions via the serotonin system. This review summarizes the functional significance of serotonin in the teleosts reproduction. © 2015 Prasad, Ogawa and Parhar.


Ng D.K.S.,University of Selangor
Chemical Engineering Journal | Year: 2010

Biorefineries are processing facilities that convert biomass into value-added products such as biofuels, specialty chemicals, and pharmaceuticals. Integrated biorefineries which consist of various processing facilities (e.g., digestion, fermentation, pyrolysis, gasification, etc.) have been proposed in order to enhance the energy efficiency and material recovery. This work presents an optimisation-based, automated targeting procedure to determine the maximum biofuel production and revenue levels in an integrated biorefinery. The approach is based on pinch analysis and allows targets to be determined prior to detailed design of the biorefinery flowsheet. A hypothetical case study is shown to illustrate the proposed approach. © 2010 Elsevier B.V.


Yule C.M.,University of Selangor
Biodiversity and Conservation | Year: 2010

The tropical peat swamp forests of Indonesia and Malaysia are unusual ecosystems that are rich in endemic species of flora, fauna and microbes despite their extreme acidic, anaerobic, nutrient poor conditions. They are an important refuge for many endangered species including orang utans. Ecosystem functioning is unusual: microbial decomposition is inhibited because the leaves are sclerophyllous and toxic to deter herbivory in the nutrient poor environment, yet bacteria are abundant and active in the surface layers of the peat, where they respire DOC leached from newly fallen leaves. The bacteria are subsequently consumed by aquatic invertebrates that are eaten by fish, and bacterially respired CO2 is assimilated by algae, so bacteria are thus vital to carbon and nutrient cycling. Peat swamp forests are highly sensitive to the impacts of logging, drainage and fire, due to the interdependence of the vegetation with the peat substrate, which relies on the maintenance of adequate water, canopy cover and leaf litter inputs. Even minor disturbances can increase the likelihood of fire, which is the major cause of CO2 emissions from regional peat swamp forests and which impact ecosystems worldwide by contributing to climate change. Indo-Malayan peat swamps affect the hydrology of surrounding ecosystems due to their large water storage capacity which slows the passage of floodwaters in wet seasons and maintains stream base flows during dry seasons. These forests are of global importance yet they are inadequately protected and vanishing rapidly, particularly due to agricultural conversion to oil palm, logging, drainage and annual fires. © Springer Science+Business Media B.V. 2008.


Ng K.Y.,University of Selangor
BMC complementary and alternative medicine | Year: 2014

BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting the senile population with manifestation of motor disability and cognitive impairment. Reactive oxygen species (ROS) is implicated in the progression of oxidative stress-related apoptosis and cell death of the midbrain dopaminergic neurons. Its interplay with mitochondrial functionality constitutes an important aspect of neuronal survival in the perspective of PD. Edible bird's nest (EBN) is an animal-derived natural food product made of saliva secreted by swiftlets from the Aerodamus genus. It contains bioactive compounds which might confer neuroprotective effects to the neurons. Hence this study aims to investigate the neuroprotective effect of EBN extracts in the neurotoxin-induced in vitro PD model.METHODS: EBN was first prepared into pancreatin-digested crude extract and water extract. In vitro PD model was generated by exposing SH-SY5Y cells to neurotoxin 6-hydroxydopamine (6-OHDA). Cytotoxicity of the extracts on SH-SY5Y cells was tested using MTT assay. Then, microscopic morphological and nuclear examination, cell viability test and ROS assay were performed to assess the protective effect of EBN extracts against 6-OHDA-induced cellular injury. Apoptotic event was later analysed with Annexin V-propidium iodide flow cytometry. To understand whether the mechanism underlying the neuroprotective effect of EBN was mediated via mitochondrial or caspase-dependent pathway, mitochondrial membrane potential (MMP) measurement and caspase-3 quantification were carried out.RESULTS: Cytotoxicity results showed that crude EBN extract did not cause SH-SY5Y cell death at concentrations up to 75 μg/ml while the maximum non-toxic dose (MNTD) of water extract was double of that of crude extract. Morphological observation and nuclear staining suggested that EBN treatment reduced the level of 6-OHDA-induced apoptotic changes in SH-SY5Y cells. MTT study further confirmed that cell viability was better improved with crude EBN extract. However, water extract exhibited higher efficacy in ameliorating ROS build up, early apoptotic membrane phosphatidylserine externalization as well as inhibition of caspase-3 cleavage. None of the EBN treatment had any effect on MMP.CONCLUSIONS: Current findings suggest that EBN extracts might confer neuroprotective effect against 6-OHDA-induced degeneration of dopaminergic neurons, particularly through inhibition of apoptosis. Thus EBN may be a viable nutraceutical option to protect against oxidative stress-related neurodegenerative disorders such as PD.


Lee C.Y.,University of Selangor
Clinical and Translational Gastroenterology | Year: 2013

Obesity is a metabolic disorder and fundamental cause of other fatal diseases including atherosclerosis and cancer. One of the main factor that contributes to the development of obesity is high-fat (HF) consumption. Lipid ingestion will initiate from the gut feedback mechanisms to regulate glucose and lipid metabolisms. But these lipid-sensing pathways are impaired in HF-induced insulin resistance, resulting in hyperglycemia. Besides that, duodenal lipid activates mucosal mast cells, leading to the disruption of the intestinal tight junction. Lipopolysaccharide that is co-transited with dietary fat postprandially, promotes the release of cytokines and the development of metabolic syndrome. HF-diet also alters microbiota composition and enhances fat storage. Although gut is protected by immune system and contains high level of antioxidants, obesity developed presumably when this protective mechanism is compromised by the presence of excessive fat. Several therapeutic approaches targeting different pathways have been proposed. There may be no one single most effective treatment, but all aimed to prevent obesity. This review will elaborate on the physiological and molecular changes in the gut that lead to obesity, and will provide a summary of potential treatments to manage these pathophysiological changes. © 2013 the American College of Gastroenterology All rights reserved.


Teo L.P.,University of Selangor
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

Eigenmodes of the electromagnetic field with perfectly conducting or infinitely permeable conditions on the boundary of a D-dimensional spherically symmetric cavity is derived explicitly. It is shown that there are (D-2) polarizations for TE modes and one polarization for TM modes, giving rise to a total of (D-1) polarizations. In case of a D-dimensional ball, the eigenfrequencies of the electromagnetic field with perfectly conducting boundary condition coincides with the eigenfrequencies of gauge 1-forms with relative boundary condition; whereas the eigenfrequencies of the electromagnetic field with infinitely permeable boundary condition coincides with the eigenfrequencies of gauge 1-forms with absolute boundary condition. Casimir energies of single and concentric spherical shells in D-dimensions are computed. The Casimir energy of concentric spherical shells can be written as a sum of the single spherical shell contributions and an interacting term, and the latter is free of divergence. The interacting term always gives rise to an attractive force between the two spherical shells. Its leading term is the Casimir force acting between two parallel plates of the same area, as expected by proximity force approximation. © 2010 The American Physical Society.


Foo D.C.Y.,University of Selangor
Clean Technologies and Environmental Policy | Year: 2013

In the past one and a half decades, resource conservation network (RCN) synthesis has been well accepted by both academics and industrial practitioners in enhancing sustainability aspect for the process industry. Various insight-based pinch analysis and mathematical optimisation techniques have been proposed to synthesise optimum RCN. For the former, the developments to date have been focusing on various targeting and design tools, with very little emphasis on the systematic assessment of process changes. The latter involves the modification of process operating conditions (e.g., flowrate, concentration, temperature, etc.), which leads to further reduction of minimum fresh resource flowrates. In this study, the plus-minus principle in heat exchanger network synthesis is extended for use with graphical targeting tool in assessing opportunities for process changes in the RCN of fixed-flowrate problems, aiming to further reduce its minimum fresh resource flowrate. Literature examples are used for illustration. © 2012 Springer-Verlag.


Teo L.P.,University of Selangor
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We consider the finite temperature Casimir interaction between two Dirichlet spheres in (D+1)-dimensional Minkowski spacetime. The Casimir interaction free energy is derived from the zero temperature Casimir interaction energy via the Matsubara formalism. In the high temperature region, the Casimir interaction is dominated by the term with zero Matsubara frequency, and it is known as the classical term since this term is independent of the Planck constant. Explicit expression of the classical term is derived and it is computed exactly using appropriate similarity transforms of matrices. We then compute the small separation asymptotic expansion of this classical term up to the next-to-leading order term. For the remaining part of the finite temperature Casimir interaction with nonzero Matsubara frequencies, we obtain its small separation asymptotic behavior by applying certain prescriptions to the corresponding asymptotic expansion at zero temperature. This gives us a leading term that is shown to agree precisely with the proximity force approximation at any temperature. The next-to-leading order term at any temperature is also derived and it is expressed as an infinite sum over integrals. To obtain the asymptotic expansion at the low and medium temperature regions, we apply the inverse Mellin transform techniques. In the low temperature region, we obtain results that agree with our previous work on the zero temperature Casimir interaction. © 2014 American Physical Society.


Teo L.P.,University of Selangor
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We consider the high-temperature limit of the Casimir interaction between a Dirichlet sphere and a Dirichlet plate due to the vacuum fluctuations of a scalar field in (D+1)-dimensional Minkowski spacetime. The high-temperature leading term of the Casimir free interaction energy is known as the classical term, since it does not depend on the Planck constant. From the functional representation of the zero-temperature Casimir interaction energy, we use Matsubara formalism to derive the finite-temperature Casimir free energy and obtain the classical term. It can be expressed as a weighted sum over logarithms of determinants. Using similarity transforms of matrices, we reexpress this classical term as an infinite series. This series is then computed exactly using a generalized Abel-Plana summation formula. From this, we deduce the short-distance asymptotic expansions of the classical Casimir interaction force. As expected, the leading term agrees with the proximity force approximation. The next two terms in the asymptotic expansion are also computed. It is observed that the ratio of the next-to-leading-order term to the leading-order term is proportional to the dimension of spacetime. Hence, a larger correction to the proximity force approximation is expected in spacetime with higher dimensions. This is similar to a previous result deduced for the zero-temperature case. © 2014 American Physical Society.


Teo L.P.,University of Selangor
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

In this article, we derive the formula for the Casimir force acting on a piston made of real material moving inside a perfectly conducting rectangular box. It is shown that by taking suitable limits, one recovers the formula for the Casimir force acting on a perfectly conducting piston or an infinitely permeable piston. The Lifshitz formula for finite temperature Casimir force acting on parallel plates made of real materials is re-derived by considering the five-layer model in the context of the piston approach. It is observed that the divergences of the Casimir force will only cancel under certain conditions, for example, when the regions separated by the plates are filled with media of the same refractive index. © 2010 The American Physical Society.

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