Browse publications by year: 2016

1. Fulltext Site-specific scFv labelling with invertase via Sortase A mechanism as a platform for antibody-antigen detection using the personal glucose meter

   Ismail NF, Lim TS

   Sci Rep, 2016 Jan 19;6:19338.

   PMID: 26782912 DOI: 10.1038/srep19338

   Abstract

   Antibody labelling to reporter molecules is gaining popularity due to its many potential applications for diagnostics and therapeutics. However, non-directional bioconjugation methods which are commonly used often results in the loss of target binding capabilities. Therefore, a site-specific enzymatic based bioconjugation such as sortase-mediated transpeptidation allows for a more rapid and efficient method of antibody conjugation for diagnostic applications. Here we describe the utilization of sortase A bioconjugation to conjugate a single chain fragment variable (scFv) to the extracellular invertase (invB) from Zymomonas mobilis with the aim of developing an invertase based immunoassay. In addition, conjugation to enhanced green fluorescent protein (eGFP) was also validated to show the flexibility of the method. The invertase conjugated complex was successfully applied for the detection of antibody-antigen interaction using a personal glucose meter (PGM) for assay readout. The setup was used in both a direct and competitive assay highlighting the robustness of the conjugate for assay development. The method provides an alternative conjugation process to allow easy exchange of antibodies to facilitate rapid development of diagnostic assays for various diseases on the PGM platform.

   MeSH terms: Antigen-Antibody Complex*; Glucose; Humans; Immunoassay; Sensitivity and Specificity; Staining and Labeling*; Blotting, Western; Biosensing Techniques*; Immunoconjugates; Point-of-Care Systems; Green Fluorescent Proteins
2. Fulltext An ansatz for solving nonlinear partial differential equations in mathematical physics

   Akbar MA, Ali NH

   Springerplus, 2016;5:24.

   PMID: 26783508 DOI: 10.1186/s40064-015-1652-9

   Abstract

   In this article, we introduce an ansatz involving exact traveling wave solutions to nonlinear partial differential equations. To obtain wave solutions using direct method, the choice of an appropriate ansatz is of great importance. We apply this ansatz to examine new and further general traveling wave solutions to the (1+1)-dimensional modified Benjamin-Bona-Mahony equation. Abundant traveling wave solutions are derived including solitons, singular solitons, periodic solutions and general solitary wave solutions. The solutions emphasize the nobility of this ansatz in providing distinct solutions to various tangible phenomena in nonlinear science and engineering. The ansatz could be more efficient tool to deal with higher dimensional nonlinear evolution equations which frequently arise in many real world physical problems.
3. A shelf-stable fluorogenic isothermal amplification assay for the detection of Burkholderia pseudomallei

   Michelle Wong Tzeling J, Yean Yean C

   Analyst, 2016 Feb 21;141(4):1246-9.

   PMID: 26783560 DOI: 10.1039/c5an01741f

   Abstract

   A shelf-stable loop-mediated isothermal amplification (LAMP) reagent for Burkholderia pseudomallei detection is described. The coupling of LAMP reagents with the indirect colorimetric indicator and consequently its lyophilization enable the simple evaluation of results without the need for any advance laboratory instruments. The reagents were found to have a stable shelf life of at least 30 days with well-maintained sensitivity and specificity.

   MeSH terms: Colorimetry; Freeze Drying; Indicators and Reagents; Laboratories; Sensitivity and Specificity; Burkholderia pseudomallei; Nucleic Acid Amplification Techniques
4. Fulltext Lysophosphatidylinositol Signalling and Metabolic Diseases

   Arifin SA, Falasca M

   Metabolites, 2016;6(1).

   PMID: 26784247 DOI: 10.3390/metabo6010006

   Abstract

   Metabolism is a chemical process used by cells to transform food-derived nutrients, such as proteins, carbohydrates and fats, into chemical and thermal energy. Whenever an alteration of this process occurs, the chemical balance within the cells is impaired and this can affect their growth and response to the environment, leading to the development of a metabolic disease. Metabolic syndrome, a cluster of several metabolic risk factors such as abdominal obesity, insulin resistance, high cholesterol and high blood pressure, and atherogenic dyslipidaemia, is increasingly common in modern society. Metabolic syndrome, as well as other diseases, such as diabetes, obesity, hyperlipidaemia and hypertension, are associated with abnormal lipid metabolism. Cellular lipids are the major component of cell membranes; they represent also a valuable source of energy and therefore play a crucial role for both cellular and physiological energy homeostasis. In this review, we will focus on the physiological and pathophysiological roles of the lysophospholipid mediator lysophosphatidylinositol (LPI) and its receptor G-protein coupled receptor 55 (GPR55) in metabolic diseases. LPI is a bioactive lipid generated by phospholipase A (PLA) family of lipases which is believed to play an important role in several diseases. Indeed LPI can affect various functions such as cell growth, differentiation and motility in a number of cell-types. Recently published data suggest that LPI plays an important role in different physiological and pathological contexts, including a role in metabolism and glucose homeostasis.

   MeSH terms: Diabetes Mellitus; Homeostasis; Hyperlipidemias; Hypertension; Insulin Resistance; Lipids; Lysophospholipids; Metabolic Diseases; Obesity; Risk Factors; Lipid Metabolism; Obesity, Abdominal
5. The buddy balloon technique to release a sticky ABSORB bioresorbable vascular scaffold balloon post-scaffolding

   Yew KL

   Int J Cardiol, 2016 Mar 15;207:1-2.

   PMID: 26784563 DOI: 10.1016/j.ijcard.2016.01.121
6. Fulltext Standardized Assessment of Biodiversity Trends in Tropical Forest Protected Areas: The End Is Not in Sight

   Beaudrot L, Ahumada JA, O'Brien T, Alvarez-Loayza P, Boekee K, Campos-Arceiz A, et al.

   PLoS Biol, 2016 Jan;14(1):e1002357.

   PMID: 26785119 DOI: 10.1371/journal.pbio.1002357

   Abstract

   Extinction rates in the Anthropocene are three orders of magnitude higher than background and disproportionately occur in the tropics, home of half the world's species. Despite global efforts to combat tropical species extinctions, lack of high-quality, objective information on tropical biodiversity has hampered quantitative evaluation of conservation strategies. In particular, the scarcity of population-level monitoring in tropical forests has stymied assessment of biodiversity outcomes, such as the status and trends of animal populations in protected areas. Here, we evaluate occupancy trends for 511 populations of terrestrial mammals and birds, representing 244 species from 15 tropical forest protected areas on three continents. For the first time to our knowledge, we use annual surveys from tropical forests worldwide that employ a standardized camera trapping protocol, and we compute data analytics that correct for imperfect detection. We found that occupancy declined in 22%, increased in 17%, and exhibited no change in 22% of populations during the last 3-8 years, while 39% of populations were detected too infrequently to assess occupancy changes. Despite extensive variability in occupancy trends, these 15 tropical protected areas have not exhibited systematic declines in biodiversity (i.e., occupancy, richness, or evenness) at the community level. Our results differ from reports of widespread biodiversity declines based on aggregated secondary data and expert opinion and suggest less extreme deterioration in tropical forest protected areas. We simultaneously fill an important conservation data gap and demonstrate the value of large-scale monitoring infrastructure and powerful analytics, which can be scaled to incorporate additional sites, ecosystems, and monitoring methods. In an era of catastrophic biodiversity loss, robust indicators produced from standardized monitoring infrastructure are critical to accurately assess population outcomes and identify conservation strategies that can avert biodiversity collapse.

   MeSH terms: Animals; Birds*; Conservation of Natural Resources*; Ecology/methods; Mammals*; Tropical Climate; Biodiversity*; Forests*
7. Progress on implantable biofuel cell: Nano-carbon functionalization for enzyme immobilization enhancement

   Babadi AA, Bagheri S, Hamid SB

   Biosens Bioelectron, 2016 May 15;79:850-60.

   PMID: 26785309 DOI: 10.1016/j.bios.2016.01.016

   Abstract

   Biofuel cells are bio-electrochemical devices, which are suitable for the environmentally friendly generation of energy. Enzymatic biofuel cell (EBFC) operates at ambient temperature and pH. Biofuel cells utilize vegetable and animal fluids (e.g. glucose) as a biofuel to produce energy. Fundamental part of each Glucose biofuel cell (GBFC) is two bioelectrodes which their surface utilizes as an enzyme immobilized site. Glucose oxidase (GOx) or glucose dehydrogenase (GDH) were immobilized on bioanode and oxidize glucose while oxygen reduced in biocathode using immobilized laccase or bilirubin oxidase in order to generate sufficient power. Glucose biofuel cells are capable to generate sufficient power for implanted devices. The key step of manufacturing a bioelectrode is the effective enzyme immobilization on the electrode surface. Due to the thin diameter of carbon nanomaterials, which make them accessible to the enzyme active sites, they are applicable materials to establish electronic communication with redox enzymes. Carbon nanomaterials regenerate the biocatalysts either by direct electron transfer or redox mediators which serve as intermediated for the electron transfer. Nano-carbon functionalization is perfectly compatible with other chemical or biological approaches to enhance the enzyme functions in implantable biofuel cells. Efficient immobilization of enzyme using the functionalized nano-carbon materials is the key point that greatly increases the possibilities of success. Current review highlights the progress on implantable biofuel cell, with focus on the nano-carbon functionalization for enzyme immobilization enhancement in glucose/O2 biofuel cells.
8. Spotlight on Athletes With a Disability: Malaysian Newspaper Coverage of the 2012 London Paralympic Games

   Cheong JP, Khoo S, Razman R

   Adapt Phys Activ Q, 2016 Jan;33(1):15-32.

   PMID: 26785497 DOI: 10.1123/APAQ.2015-0021

   Abstract

   This study analyzed newspaper coverage of the 2012 London Paralympic Games by 8 Malaysian newspapers. Articles and photographs from 4 English-language and 4 Malay-language newspapers were examined from August 28 (1 day before the Games) to September 10, 2012 (1 day after the Games closing). Tables, graphs, letters, fact boxes, and lists of events were excluded from analysis. A total of 132 articles and 131 photographs were analyzed. Content analysis of the newspaper articles revealed that most (62.8%) of the articles contained positive reference to the athletes with a disability. There were equal numbers (39.1%) of action and static shots of athletes. More articles and photographs of Malaysian (58%) than non-Malaysian (42%) athletes with a disability were identified. Only 14.9% of the articles and photographs were related to female athletes with a disability.
9. Streptomyces humi sp. nov., an actinobacterium isolated from soil of a mangrove forest

   Zainal N, Ser HL, Yin WF, Tee KK, Lee LH, Chan KG

   Antonie Van Leeuwenhoek, 2016 Mar;109(3):467-74.

   PMID: 26786500 DOI: 10.1007/s10482-016-0653-1

   Abstract

   A novel Streptomyces strain, MUSC 119(T), was isolated from a soil collected from a mangrove forest. Cells of MUSC 119(T) stained Gram-positive and formed light brownish grey aerial mycelium and grayish yellowish brown substrate mycelium on ISP 2 medium. A polyphasic approach was used to determine the taxonomic status of strain MUSC 119(T), which shows a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces. The cell wall peptidoglycan consisted of LL-diaminopimelic acid. The predominant menaquinones were identified as MK-9(H8), MK-9(H6) and MK-9(H4). The polar lipid profile consisted of phosphatidylinositol, phosphatidylethanolamine, glycolipids, diphosphatidylglycerol and four phospholipids. The predominant cellular fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. The cell wall sugars were glucose, mannose, ribose and rhamnose. The phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain MUSC119(T) to be closely related to Streptomyces rhizophilus JR-41(T) (99.0 % sequence similarity), S. panaciradicis 1MR-8(T) (98.9 %), S. gramineus JR-43(T) (98.8 %) and S. graminisoli JR-19(T) (98.7 %). These results suggest that MUSC 119(T) should be placed within the genus Streptomyces. DNA-DNA relatedness values between MUSC 119(T) to closely related strains ranged from 14.5 ± 1.3 to 27.5 ± 0.7 %. The G+C content was determined to be 72.6 mol  %. The polyphasic study of MUSC 119(T) showed that this strain represents a novel species, for which the name Streptomyces humi sp. nov. is proposed. The type strain of S. humi is MUSC 119(T) (=DSM 42174(T) = MCCC 1K00505(T)).
10. Fulltext Characterization of Gold-Sputtered Zinc Oxide Nanorods-a Potential Hybrid Material

    Perumal V, Hashim U, Gopinath SC, Rajintra Prasad H, Wei-Wen L, Balakrishnan SR, et al.

    Nanoscale Res Lett, 2016 Dec;11(1):31.

    PMID: 26787050 DOI: 10.1186/s11671-016-1245-8

    Abstract

    Generation of hybrid nanostructures has been attested as a promising approach to develop high-performance sensing substrates. Herein, hybrid zinc oxide (ZnO) nanorod dopants with different gold (Au) thicknesses were grown on silicon wafer and studied for their impact on physical, optical and electrical characteristics. Structural patterns displayed that ZnO crystal lattice is in preferred c-axis orientation and proved the higher purities. Observations under field emission scanning electron microscopy revealed the coverage of ZnO nanorods by Au-spots having diameters in the average ranges of 5-10 nm, as determined under transmission electron microscopy. Impedance spectroscopic analysis of Au-sputtered ZnO nanorods was carried out in the frequency range of 1 to 100 MHz with applied AC amplitude of 1 V RMS. The obtained results showed significant changes in the electrical properties (conductance and dielectric constant) with nanostructures. A clear demonstration with 30-nm thickness of Au-sputtering was apparent to be ideal for downstream applications, due to the lowest variation in resistance value of grain boundary, which has dynamic and superior characteristics.
11. Incidental Splenic Granuloma Due to Burkholderia pseudomallei: A Case of Asymptomatic Latent Melioidosis?

    Chow TK, Eu LC, Chin KF, Ong KC, Pailoor J, Vadivelu J, et al.

    Am J Trop Med Hyg, 2016 Mar 2;94(3):522-4.

    PMID: 26787155 DOI: 10.4269/ajtmh.15-0774

    Abstract

    We report a rare case of an asymptomatic latent melioidosis lesion in a posttraumatic splenectomy specimen from a diabetic patient. The 2-cm yellowish, lobulated lesion was found in the splenic parenchyma well away from the traumatized areas. Microscopically, it consisted of a central area of necrosis and exudate surrounded by macrophages, epithelioid cells, lymphocytes, and occasional multinucleated giant cells. Burkholderia bacilli were detected by a novel in situ hybridization (ISH) assay, and confirmed by polymerase chain reaction and sequencing to be Burkholderia pseudomallei. As melioidosis was not suspected initially, bacterial culture was not done but electron microscopy showed morphologically viable and dividing bacilli in the lesion. Moreover, the surgical wound became infected with B. pseudomallei several days post-surgery. After treatment with ceftazidime and trimethoprim/sulfamethoxazole, the wound infection cleared. We believe this could be a unique case of asymptomatic latent melioidosis in the spleen. In endemic countries, chronic granulomas should be investigated for B. pseudomallei infection, and if available, ISH may be helpful for diagnosis.

    MeSH terms: Bacillus; Ceftazidime; Diabetes Mellitus; Granuloma; Humans; Lactobacillus casei; Lymphocytes; Melioidosis; Microscopy, Electron; Spleen; Splenectomy; Wound Infection; Epithelioid Cells; Trimethoprim, Sulfamethoxazole Drug Combination; Giant Cells; Polymerase Chain Reaction; Burkholderia pseudomallei; In Situ Hybridization; Burkholderia; Surgical Wound
12. Purinergic P2Y6 receptors heterodimerize with angiotensin AT1 receptors to promote angiotensin II-induced hypertension

    Nishimura A, Sunggip C, Tozaki-Saitoh H, Shimauchi T, Numaga-Tomita T, Hirano K, et al.

    Sci Signal, 2016 Jan 19;9(411):ra7.

    PMID: 26787451 DOI: 10.1126/scisignal.aac9187

    Abstract

    The angiotensin (Ang) type 1 receptor (AT1R) promotes functional and structural integrity of the arterial wall to contribute to vascular homeostasis, but this receptor also promotes hypertension. In our investigation of how Ang II signals are converted by the AT1R from physiological to pathological outputs, we found that the purinergic P2Y6 receptor (P2Y6R), an inflammation-inducible G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor (GPCR), promoted Ang II-induced hypertension in mice. In mice, deletion of P2Y6R attenuated Ang II-induced increase in blood pressure, vascular remodeling, oxidative stress, and endothelial dysfunction. AT1R and P2Y6R formed stable heterodimers, which enhanced G protein-dependent vascular hypertrophy but reduced β-arrestin-dependent AT1R internalization. Pharmacological disruption of AT1R-P2Y6R heterodimers by the P2Y6R antagonist MRS2578 suppressed Ang II-induced hypertension in mice. Furthermore, P2Y6R abundance increased with age in vascular smooth muscle cells. The increased abundance of P2Y6R converted AT1R-stimulated signaling in vascular smooth muscle cells from β-arrestin-dependent proliferation to G protein-dependent hypertrophy. These results suggest that increased formation of AT1R-P2Y6R heterodimers with age may increase the likelihood of hypertension induced by Ang II.
13. Effect of plasticizer type and concentration on physical properties of biodegradable films based on sugar palm (arenga pinnata) starch for food packaging

    Sanyang ML, Sapuan SM, Jawaid M, Ishak MR, Sahari J

    J Food Sci Technol, 2016 Jan;53(1):326-36.

    PMID: 26787952 DOI: 10.1007/s13197-015-2009-7

    Abstract

    In this study, sugar palm starch (SPS) films were developed using glycerol (G), sorbitol (S) or their combination (GS) as plasticizers at the ratio of 15, 30 and 45 (wt)% using casting technique. The addition of plasticizers to SPS film-forming solutions helped to overcome the brittle and fragile nature of unplasticized SPS films. Increased plasticizer concentration resulted to an increase in film thickness, moisture content and solubility. On the contrary, density and water absorption of plasticized films decreased with increasing plasticizer concentration. Raising the plasticizer content from 15 to 45 % showed less effect on the moisture content and water absorption of S-plasticized films. Films containing glycerol and glycerol-sorbitol plasticizer (G, and GS) demonstrated higher moisture content, solubility and water absorption capacity compared to S-plasticized films. The results obtained in this study showed that plasticizer type and concentration significantly improves film properties and enhances their suitability for food packaging applications.

    MeSH terms: Glycerol; Plant Extracts; Plasticizers; Solubility; Sorbitol; Starch; Water; Food Packaging; Physical Phenomena
14. Fulltext Quality changes of stabilizer-free natural peanut butter during storage

    Mohd Rozalli NH, Chin NL, Yusof YA, Mahyudin N

    J Food Sci Technol, 2016 Jan;53(1):694-702.

    PMID: 26787989 DOI: 10.1007/s13197-015-2006-x

    Abstract

    The storage stability of preservative-free peanut butter was evaluated for changes in physicochemical quality including moisture content and water activity, microbiological properties, oxidative stability and textural quality in terms of spreadability and firmness. The study was conducted for 16 weeks at storage temperature of 10, 25 and 35 °C on natural and pure peanut butter produced from two varieties of peanuts, the Virginia and Spanish TMV-2 varieties of China and India origin, respectively. The peanuts were ground using a high speed grinder for 2.5 and 3.0 min to produce peanut butter without addition of other ingredient. The natural peanut butter exhibited stability and had acceptable microbial count during storage. Storage at 10 °C gave similar textural quality with commercial product until week 8 and without appreciable loss in oxidative stability until week 12. At higher storage temperatures of 25 and 35 °C, oxidative stability was shortened to 4 weeks of storage. Among the factors of storage temperature and time, grinding time and peanut variety, storage temperature had the most significant effects on quality changes of natural peanut butter.
15. Fulltext Probable impact of age and hypoxia on proliferation and microRNA expression profile of bone marrow-derived human mesenchymal stem cells

    Mohd Ali N, Boo L, Yeap SK, Ky H, Satharasinghe DA, Liew WC, et al.

    PeerJ, 2016;4:e1536.

    PMID: 26788424 DOI: 10.7717/peerj.1536

    Abstract

    Decline in the therapeutic potential of bone marrow-derived mesenchymal stem cells (MSC) is often seen with older donors as compared to young. Although hypoxia is known as an approach to improve the therapeutic potential of MSC in term of cell proliferation and differentiation capacity, its effects on MSC from aged donors have not been well studied. To evaluate the influence of hypoxia on different age groups, MSC from young (<30 years) and aged (>60 years) donors were expanded under hypoxic (5% O2) and normal (20% O2) culture conditions. MSC from old donors exhibited a reduction in proliferation rate and differentiation potential together with the accumulation of senescence features compared to that of young donors. However, MSC cultured under hypoxic condition showed enhanced self-renewing and proliferation capacity in both age groups as compared to normal condition. Bioinformatic analysis of the gene ontology (GO) and KEGG pathway under hypoxic culture condition identified hypoxia-inducible miRNAs that were found to target transcriptional activity leading to enhanced cell proliferation, migration as well as decrease in growth arrest and apoptosis through the activation of multiple signaling pathways. Overall, differentially expressed miRNA provided additional information to describe the biological changes of young and aged MSCs expansion under hypoxic culture condition at the molecular level. Based on our findings, the therapeutic potential hierarchy of MSC according to donor's age group and culture conditions can be categorized in the following order: young (hypoxia) > young (normoxia) > old aged (hypoxia) > old aged (normoxia).

    MeSH terms: Bone Marrow; Cell Differentiation; Signal Transduction; Apoptosis; Computational Biology; MicroRNAs; Cell Proliferation; Gene Ontology
16. Effects of tempol on altered metabolism and renal vascular responsiveness in fructose-fed rats

    Abdulla MH, Sattar MA, Johns EJ

    Appl Physiol Nutr Metab, 2016 Feb;41(2):210-8.

    PMID: 26789093 DOI: 10.1139/apnm-2015-0411

    Abstract

    This study investigated the effect of tempol (a superoxide dismutase mimetic) on renal vasoconstrictor responses to angiotensin II (Ang II) and adrenergic agonists in fructose-fed Sprague-Dawley rats (a model of metabolic syndrome). Rats were fed 20% fructose in drinking water (F) for 8 weeks. One fructose-fed group received tempol (FT) at 1 mmol·L(-1) in drinking water for 8 weeks or as an infusion (1.5 mg·kg(-1)·min(-1)) intrarenally. At the end of the treatment regimen, the renal responses to noradrenaline, phenylephrine, methoxamine, and Ang II were determined. F rats exhibited hyperinsulinemia, hyperuricemia, hypertriglyceridemia, and hypertension. Tempol reduced blood glucose and insulin levels (all p < 0.05) in FT rats compared with their untreated counterparts. The vasoconstriction response to all agonists was lower in F rats than in control rats by about 35%-65% (all p < 0.05). Vasoconstrictor responses to noradrenaline, phenylephrine, and methoxamine but not Ang II were about 41%-75% higher in FT rats compared with F rats (all p < 0.05). Acute tempol infusion blunted responses to noradrenaline, methoxamine, and Ang II in control rats by 32%, 33%, and 62%, while it blunted responses to noradrenaline and Ang II in F rats by 26% and 32%, respectively (all p < 0.05), compared with their untreated counterparts. Superoxide radicals play a crucial role in controlling renal vascular responses to adrenergic agonists in insulin-resistant rats. Chronic but not acute tempol treatment enhances renal vascular responsiveness in fructose-fed rats.
17. Congenital myasthenic syndrome due to novel CHAT mutations in an ethnic kadazandusun family

    Tan JS, Ambang T, Ahmad-Annuar A, Rajahram GS, Wong KT, Goh KJ

    Muscle Nerve, 2016 May;53(5):822-826.

    PMID: 26789281 DOI: 10.1002/mus.25037

    Abstract

    Choline acetyltransferase (CHAT) gene mutations cause a rare presynaptic congenital myasthenic syndrome due to impaired acetylcholine resynthesis.
18. Fulltext Factors associated with alcohol use before or during sex among men who have sex with men in a large internet sample from Asia

    Yang C, Guadamuz TE, Lim SH, Koe S, Wei C

    LGBT Health, 2016 Apr;3(2):168-74.

    PMID: 26789393 DOI: 10.1089/lgbt.2014.0041

    Abstract

    We explored factors associated with alcohol use before or during sex among a sample of 10,861 men who have sex with men (MSM) in Asia who were recruited online for the study. Multinomial logistic regression analysis indicated that having sex under the influence of alcohol was associated with having multiple male partners, seeking partners primarily through gay bar/gym/dance party/friends, selling sex and using multiple drugs during the past 6 months, and unprotected anal sex. More efforts are needed to better assess alcohol use and misuse among MSM in Asia and understand contextual influences on alcohol use and HIV-related behaviors in order to implement culturally-specific interventions.

    MeSH terms: Adult; Alcohol Drinking; Cross-Sectional Studies; Homosexuality, Male*; Internet
19. Fulltext Ringed Seal Search for Global Optimization via a Sensitive Search Model

    Saadi Y, Yanto IT, Herawan T, Balakrishnan V, Chiroma H, Risnumawan A

    PLoS One, 2016;11(1):e0144371.

    PMID: 26790131 DOI: 10.1371/journal.pone.0144371

    Abstract

    The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS) is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive) and exploitation (intensive) of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be used in global optimization problems.

    MeSH terms: Algorithms; Animals; Behavior, Animal/physiology*; Computer Simulation; Models, Theoretical; Seals, Earless/physiology*
20. Effects of demographic and physical factors on nerve conduction study values of healthy subjects in a multi-ethnic Asian population

    Fong SY, Goh KJ, Shahrizaila N, Wong KT, Tan CT

    Muscle Nerve, 2016 08;54(2):244-8.

    PMID: 26790132 DOI: 10.1002/mus.25029

    Abstract

    INTRODUCTION: We investigated the effects of demographic and physical factors on nerve conduction studies (NCS) in a multi-ethnic Asian population.

    METHODS: One hundred sixty-six healthy Malaysians of different ethnicities (51.2% women, aged 21-77 years) underwent NCS using a standard protocol. Correlations of various factors to NCS were determined, and multiple linear regression analysis was used to develop predictive equations for each parameter.

    RESULTS: Age and ethnicity were the commonest independent factors influencing NCS followed by gender, height, weight, and body mass index. Increasing age predicted a reduction in lower limb motor and all sensory nerve action potential amplitudes and decrease in motor and sensory (except sural) conduction velocities. Ethnic Indians had slower motor and sensory conduction velocities in several nerves and also had differences in action potential amplitudes.

    CONCLUSIONS: NCS parameters in multi-ethnic Malaysians were influenced independently by various demographic and physical factors, including ethnicity. Muscle Nerve 54: 244-248, 2016.

    MeSH terms: Action Potentials/physiology*; Adult; Aged; Analysis of Variance; Demography; Female; Humans; Male; Middle Aged; Neural Conduction/physiology*; Regression Analysis; Asian Continental Ancestry Group; Young Adult; Healthy Volunteers