Browse publications by year: 2015

  1. Kamarul Aini Mohd Sar, Sohif Mat, Khairiah Haji Badri, Muhammad Fauzi Mohd Zain
    Sains Malaysiana, 2015;44:771-778.
    Research on the development of lightweight concrete (LWC) utilizing wastes and natural resources as lightweight
    aggregates (LWA) is increasingly gaining attention worldwide due to sustainable and environmental concerns. A new
    alternative is using palm kernel oil polyol (PKO-p)-based polyurethane (PU) as filler. Rigid PU is a block copolymer
    comprised of a monomeric PKO-p and 2, 4-methylene diphenyl diisocyanate (crude MDI). The property of PKO-p, its
    ratio with crude MDI and reaction time were determined. The reaction time showed the average of 60 s for cream
    time and 95 s for rise time with maximum hardening time of 8 min. The reaction between PKO-p to MDI at 1:1 ratio
    resulted in a very short hardening time (within 2 min). The compressive strength of the rigid PU was at 7.0 MPa at a
    density of 206 kg/m3
    . Further increase in the amount of PKO-p increased the density and compressive strength of the
    PU. PU aggregate in the concrete mixture was added at 1 to 5% (w/w) to obtain concrete with density of less than 1800
    kg/m3
    . The resulting concrete has excellent compressive strength (17.5 MPa) and thermal conductivity (0.24 W/m⋅K).
    The results showed that physical properties of PU played the most significant effect on the physical and mechanical
    properties of the lightweight concrete
  2. Mansoor Saburov, Mohd Ali Khameini Ahmad
    Sains Malaysiana, 2015;44:765-769.
    We provide the number of solutions of a cubic equation in domains , 3
    \ , 3
    \ 3 and 3
    .
  3. Samat SB, Priharti W
    Sains Malaysiana, 2015;44:761-764.
    A HPGe detector and γ-ray multinuclide standard solution were used to get several data pairs of photon energy E and
    detector’s energy resolution FWHM. A series of graph of FWHM2
    versus E was plotted to determine the detector’s Fano
    factor and pre-amplifier noise, which yielded the mean values of 0.123±0.003 and (7.448±0.011) × 10−1 keV, respectively.
    The Fano factor value agrees within 95% confident interval with the mostly quoted value of 0.13 for semiconductor
    detectors. The obtained preamplifier noise is in agreement with typical manufacturer’s specification.
  4. Sri Harjanto, Latifa N. Noviana, Mia Diniati, Stefanno W. Yunior, Nasruddin
    Sains Malaysiana, 2015;44:747-752.
    Coal-based activated carbon materials is a prospective materials for hydrogen storage application. The present work
    aimed to study the effect of post treatments including mechanical milling process and pelletization and simulating
    experimentally the conditions of pelletization of fine particles of activated coal. Post treatment of activated coal consist
    of 2 steps mechanical milling process in planetary ball mill followed by pelletization. First step of mechanical milling
    process gave particle size reduction and second step was undertaken to maintain activity of activated coal. Second step
    of mechanochemical process were done in dry (ACP-A) and wet condition (ACP-B) with the ratio of sample: KOH was
    1:1 and performed for 1 h. Then they will be formed into pellets with the addition of binder which contained fructose,
    glucose and oligo. Some examinations such as PSA, BET, SEM and XRD were performed to determine the characteristics of
    activated carbon materials including hydrogen adsorption capacity testing. Particle size reduction of activated carbon
    reached 98.9% after planetary ball milling. The raw material of activated carbon (AC) has hydrogen adsorption as much
    as from 0.30 and 0.25 wt. % from -5 and 25o
    C measurements, respectively. As predicted the adsorption of hydrogen gas
    of pelletized activated carbon from bituminous coal decreased due to post treatment process about 47% for ACP-A and
    60% for ACP-B at 4000 Bar.
    MeSH terms: Adsorption; Charcoal; Coal; Excipients; Fructose; Glucose; Hydrogen; Maintenance; Particle Size; Prospective Studies; Mechanical Phenomena
  5. Khoo EM, Su May Liew, Cheong AT, Wai KL, Azah Abdul Samad, Ainul Nadziha Mohd Hanafiah, et al.
    Sains Malaysiana, 2015;44(5):741-746.
    There has been an epidemiological transition in morbidity and mortality patterns in developing countries. This study
    aimed to determine whether there was an accompanying change in disease presentation in primary care. This was
    a cross-sectional study conducted at 12 public primary care clinics in Malaysia. Outpatient medical records were
    randomly selected and reviewed to identify patients’ reasons for encounter. The overall retrieval of records was 99.1%
    (n=1,753; range 95.7-100.0%). The mean age was 33.1 (SD 22.2) years. For all ages, the most common reasons for
    patient encounter (RFE) were cough (21.1%; 95% CI 16.5, 25.8), follow-up care for chronic diseases (19.6%; 95% CI
    12.7, 26.6) and fever (18.4%; 95% CI 14.2, 22.5). The top RFE in West Malaysia was follow-up care for chronic diseases
    while in East Malaysia, the most common RFE was cough (25.2%; 95% CI 16.8, 33.6) and fever (21.7%; 95% CI 14.3,
    29.0). In conclusion, there is a change in the presentation of diseases, with chronic disease emerging as one of the top
    RFE in primary care. In adults, for all age groups over 40 years old, care for chronic diseases has overtaken acute disease
    care. However, acute respiratory problems remain the overall top RFE at public primary care clinics in Malaysia. There
    are major differences in morbidity patterns and reasons for encounter for different age groups and geographical areas
    and this could be utilized for better health care planning.
  6. Tzar M, Norazlah B, Shamsul A
    Sains Malaysiana, 2015;44:735-740.
    Candidaemia carries high morbidity and mortality, but its conventional diagnosis is time consuming and insensitive.
    Clinical risk factors may identify suitable candidates for prophylactic or pre-emptive antifungal therapy and may be
    modified or controlled to prevent candidaemia. Therefore, this study aimed to identify the independent risk factors for
    candidaemia. The study was a retrospective, case-control study involving 54 patients with candidaemia and 54 patients
    without candidaemia as controls. The patient’s data were collected from the medical records and the risk factors for
    candidaemia were analyzed in both groups. Candida species isolated from blood were C. tropicalis (n=19, 35.2%), C.
    albicans (n=18, 33.3%), C. parapsilosis (n=11, 20.4%) and one isolate each (1.9%) of C. famata, C. glabrata, C. krusei, C.
    melibiosica, C. pelliculosa and C. sake. Multivariate analysis showed that renal insufficiency, prior antibacterial therapy,
    prior antifungal therapy, steroid therapy and urinary catheterization were independent risk factors for candidaemia.
    Central venous catheter, prolonged hospital stay, intensive care unit stay, mechanical ventilation, surgery and parenteral
    nutrition occurred more commonly among the candidaemia group but were not independently significant. Controlling,
    limiting or modifying these risk factors may reduce the incidence of candidaemia.
  7. Mohd Rohaizad Md Roduan, Norhafizah Mohtarrudin, Chong PP, Malina Osman, Noraini Mohd Dusa
    Sains Malaysiana, 2015;44:727-733.
    Inflammation plays an important role to the process of prostate carcinogenesis by increasing the rate of cell proliferation,
    which contributes to an aggressive tumour phenotype. Cyclooxygenase-2 (COX-2) has been found overexpressed in
    various types of cancer cells including prostate. The aim of this study was to investigate the COX-2 expressions in different
    types of human prostate tissues. Paraffin-embedded prostate tissues from 263 samples were examined for the expression
    of COX-2 marker by immunohistochemistry method. COX-2 was found highly expressed in prostate adenocarcinoma
    (p=0.001) as compared to benign and normal tissues. The score of COX-2 expressions in most of normal prostate was
    weak 49 (77.8%), while only 16 (16%) of BPH showed strong expression. 56 cases (56%) prostate cancer showed strong
    COX-2 expression. Prostate cancer cases showed significant differences in staining patterns as tumour grade increased.
    In addition, COX-2 expression was significantly correlated with Gleason score in cancerous tissues. This study suggests
    that COX-2 overexpression is associated with prostate cancer and higher grade tumour.
    MeSH terms: Adenocarcinoma; Humans; Immunohistochemistry; Inflammation; Male; Phenotype; Prostatic Neoplasms; Staining and Labeling; Paraffin Embedding; Cell Proliferation; Cyclooxygenase 2; Neoplasm Grading; Carcinogenesis
  8. Xiaofeng Tian, Linsong Cheng, Wenqi Zhao, Yiqun Yan, Xiaohui He, Qiang Guo
    Sains Malaysiana, 2015;44:719-725.
    In this paper, seven permeability stress sensitivity experiments were conducted to show the features of permeability stress
    sensitivity. The cores in the experiments were taken from the tight sandstone oil reservoir in Ordos Basin. Then advanced
    technologies, such as casting thin section, scanning electron microscope and rate-controlled mercury penetration, were
    applied to explain the mechanism of permeability stress sensitivity in tight oil reservoirs. The results indicated that
    the permeability reduction and recovery in gas permeability stress sensitivity increases as the permeability decreases.
    This was resulted from the maximal throat radius. The permeability reduction in liquid permeability stress sensitivity
    increases at first and then decreases as the permeability decreases. The permeability recovery decreases to zero as the
    permeability decreases. Additionally, the differences between gas and liquid permeability stress sensitivity become greater
    as the permeability decreases. These were resulted from the effect of the critical throat radius. This paper corrects the
    mistakes about the stress sensitivity in tight oil reservoirs from gas permeability stress sensitivity experiments which is
    significant to the development of tight sandstone oil reservoirs.
    MeSH terms: Bismuth; Mercury; Microscopy, Electron, Scanning; Neck; Permeability; Pharynx; Radius; Salicylates; Oil and Gas Fields
  9. Prommi T, Payakka A
    Sains Malaysiana, 2015;44:707-717.
    Biodiversity of aquatic insect and physicochemical water quality parameters in Mae Tao and Mae Ku watersheds were
    assessed bi-monthly from February 2011 to February 2012. A total of 59 families representing 9 orders were recorded.
    At order level, Trichoptera was found at the highest frequency in total abundance (45.75%) followed by Ephemeroptera
    (18.06%), Hemiptera (13.45%), Odonata (9.62%), Diptera (8.17%), Coleoptera (4.6%), Megaloptera (0.17%),
    Lepidoptera (0.11%) and Plecoptera (0.07%). The family Hydropsychidae was the most prominent and the most abundant
    aquatic insect taxa followed by Chironomidae. Water temperature, dissolved oxygen and ammonia-nitrogen were similar
    at all sampling stations. Significant variations in pH, electrical conductivity, total dissolved solids, sulfate, nitrate-nitrogen
    and alkalinity were found at all sampling stations. Taxa richness and diversity index significantly correlated with dissolved
    oxygen, sulfate, nitrate-nitrogen and ammonia-nitrogen (p<0.05, p<0.01). Physicochemical data and biological data
    showed that mostly the surface water quality in Mae Tao and Mae Ku watersheds were within Type III of The Surface
    Water Standard for Agriculture and Water Quality for Protection of Aquatic Resources in Thailand.
    MeSH terms: Agriculture; Ammonia; Animals; Chironomidae; Electric Conductivity; Hemiptera; Lepidoptera; Nitrates; Nitrogen; Oxygen; Sulfates; Temperature; Thailand; Water; Biodiversity; Water Quality; Odonata; Ephemeroptera
  10. Tengku Haziyamin Tengku Abdul Hamid, Sharul Azim Mohd Ghazali
    Sains Malaysiana, 2015;44:701-706.
    Microbial lipolytic enzymes have attracted considerable attention owing to their biotechnological potential. In this
    study, thermophilic bacteria producing lipase were isolated from Bentong and Sungai Lembing hot springs, in Pahang,
    Malaysia. Out of 25 colonies isolated, 14 samples showed to produce clear zones surrounding the growth on tributyrin
    and trioelin agar plates. All 14 isolates showed Gram-negative bacteria with short rod morphology. PCR amplification
    of 16S ribosomal DNA gene showed that these isolates were clustered with subclass β-proteobacteria consisting of
    thermophilic bacteria that produce lipase. Phylogenetic analysis was carried out with the highly similar species and
    4 isolates (SglA1, BtnC1, BtnC2 and BtnC3) are related to genus Caldimonas and 10 isolates (SglB1, SglB2, SglB3,
    SglB4, BtnB1, BtnB2 BtnD1, BtnD2, BtnD3 and BtnD4) belonged to genus Tepidimonas. These results indicated that
    novel lipase-producing thermophilic β-proteobacteria could be isolated from these hot springs.
  11. Mohammad Saiful Mansor, Rosli Ramli, Mohammad Saiful Mansor, Shahrul Anuar Mohd Sah
    Sains Malaysiana, 2015;44:687-692.
    Foraging pattern of Chestnut-winged Babbler (Stachyris erythroptera) and Abbott’s Babbler (Malacocincla abbotti) was
    studied in Lenggong Valley, Perak from July 2010 until July 2011. The study examines the patterns of foraging height,
    foraging substrates and attack manoeuvres of two babbler species (Family: Timaliidae), to explain how these trophically
    similar species can coexist in the same habitat; a central question in ecology. Information on the foraging height, foraging
    substrate and attack manoeuvres was collected independently for each foraging bird. Principal component analysis and
    Pearson’s correlation analysis showed that these two species used similar proportion of foraging height (>0-2 m above
    the ground) and foraging substrate (dead leaves), but differed in the use of attack manoeuvres. The Chestnut-winged
    babbler used primarily stretching manoeuvre, whereas the Abbott’s babbler used primarily gleaning manoeuvre. This
    niche separation allowed these species to coexist in the same area, thus follows the Gause’ Law of competitive exclusion,
    that states two species occupying the same niches will not coexist forever.
  12. Souad Neffar, Haroun Chenchouni, Arifa Beddiar
    Sains Malaysiana, 2015;44:671-680.
    Mycorrhizal fungi are an essential component to consider for better management of soil fertility, particularly in
    degraded rangelands of drylands. The present article presents a field survey of colonization and intensity of arbuscular
    mycorrhizal fungi (AMF) on prickly pear (Opuntia ficus-indica) roots from young (5 years old) and old (more than 20
    years) plantations. The results observed were explained by seasonality and edaphic factors. Prickly pear roots showed
    a mycorrhizal frequency (F%) up to 100% of colonization and a mycorrhizal intensity (M%) that may exceed 70%.
    According to ANOVAs, both F% and M% varied significantly between Prickly pear plantation ages, but only M% between
    seasons. The Generalized linear model showed that edaphic factors have no effect on the variation of F%. However
    the statistical model showed that M% were significantly influenced by active CaCO3
    , organic matter, carbon, nitrogen,
    phosphorus contents and C/N. Our findings highlight the importance of mycorrhization in rehabilitation programs of
    degraded rangelands by prickly pear plantations in semiarid and arid lands, particularly during early plant ages and
    under environmental abiotic stresses such as climate and soil type.
    MeSH terms: Carbon; Climate; Nerve Tissue Proteins; Nitrogen; Phosphorus; Surveys and Questionnaires; Seasons; Soil; Linear Models; RNA-Binding Proteins; Plant Roots; Opuntia; Mycorrhizae
  13. Melek Zeng?n, Semra Sayg?n, Nazm? Polat
    Sains Malaysiana, 2015;44:657-662.
    Otoliths, which can be used for the evaluation of relationships between the environment and organisms, are structures
    consisting of calcium carbonate. The aim of this study was to realize the shape analysis. In addition, it is to detect the
    characteristics of otolith biometrics in order to determine the relationship between the fish size of Engraulis encrasicolus
    L. from the Black and Marmara Seas. The samples were obtained from the Black and Marmara Seas between December
    2013 and February 2014. The relationships between the TL (Total length) and OL (Otolith length), TL and OB (Otolith
    breadth), and TL and OW (Otolith weight) were determined using the linear regression equation. Form factor, roundness,
    circularity and rectangularity were used for shape analyses. According to the data, there was no difference between
    localities (p>0.05). Moreover, there was no difference between the left and right otoliths of the individuals sampled from
    the same locality (p>0.05). According to the regression coefficient for relationships of TL-OL, TL-OB and TL-OW, otolith
    length was identified as the best index for estimating fish length (r
    2
    >0.70). It showed that index values were statistically
    different between two populations (p<0.001).
    MeSH terms: Animals; Biometry; Body Weights and Measures; Calcium Carbonate; Environment; Fishes; Otolithic Membrane; Linear Models
  14. Noorma Wati Haron, Nordiyanah Anuar, Rubashiny Veeramohan
    Sains Malaysiana, 2015;44:643-650.
    A comparative leaf micromorphological study of Melastoma malabathricum, M. malabathricum var. alba and M.
    sanguineum (Melastomataceae) was carried out by scanning electron microscope. Characters such as epidermal cell
    shape, trichomes and stomatal type and distribution were observed. Non-glandular trichomes are present in all species
    examined. The stomata are all of paracytic type and dispersed randomly over the whole abaxial surface. The patterns of
    surface sculpturing and outer stomatal rim are unique in all the species examined. Leaf micromorphology has significant
    taxonomic value in the genus Melastoma and the present study has added some new taxonomic information for the genus
    Melastoma.
    MeSH terms: Microscopy, Electron, Scanning; Sculpture; Plant Leaves; Plant Epidermis; Melastomataceae; Trichomes
  15. Mansoor Saburov, Mohd Ali Khameini Ahmad
    Sains Malaysiana, 2015;44:635-641.
    We provide a solvability criterion for a cubic equation in domains , 3
    , and 3
    .
  16. Onuoha M, Ismail I, Piroozian A, Mamat N, Ismail A
    Sains Malaysiana, 2015;44:629-634.
    This research work presents the experimental results of the effect of polypropylene beads’ concentrations in waterbased
    mud on wellbore cleaning. A comparative study of cuttings transport performance (CTP) of water-based mud and
    water-based mud with polypropylene beads were carried out at different hole angles of 0°, 30°, 60°. 75° and 90° in a
    13 ft (3.96 m) acrylic concentric annulus flow test section, having a 2 in (50.8 mm) casing ID and a fixed 0.79 in (20
    mm) inner pipe OD. A total of 100 runs had been accomplished using fine sands (from Tanjung Balau, Johor Bahru,
    Malaysia), of size ranging from 5/127 - 6/127" (1.0 – 1.2 mm) and density 2.4 g/cc (2400 kg/m3
    ), with the mud density
    and viscosity maintained at 9 ppg (1078 kg/m3
    ) and 5 cp (0.005 Pa.s), respectively, in a flow velocity of 2.1 ft/s (0.64
    m/s). Polypropylene beads used in this study have the following properties: 290 kg/cm2 of tensile strength at yield, 0.86
    g/cc (860 kg/m3
    ) density, 4 mm (20/127") size, 82 R scale Rockwell hardness, 13,500 kg/cm2 flexural modulus, 85°C
    heat deflection temperature at 4.6 kg/cm2
    , 4 g/10 min melt flow rate at 230°C and spherical in shape. The experimental
    findings showed that commingling the basic mud with polypropylene beads has successfully introduced a buoyant force
    which was found to have improved the cuttings transport performance by more than 10% when weight concentration of
    the polypropylene beads was increased to 1.5% as compared with the performance obtained from the basic water-based
    mud. The improvement of cuttings transport performance was found to be more significant in a vertical hole.
  17. Ting T, Crouse K, Ahmad H
    Sains Malaysiana, 2015;44:619-628.
    Three novel ruthenium(II) complexes of the general formula [Ru(II)(bpy)2
    L]2+ were synthesized, where L =
    1,10-phenanthroline derivatives of position 2 imidazole having 3,4-didecyloxy-phenyl (ddip), 3,4-ditetradecyloxy-phenyl
    (dtip) and 3,4-dihexadecyloxy-phenyl (dhip). All complexes were characterized by elemental analysis, 1
    H-NMR and ESI-MS.
    Their photophysical properties have also been studied by UV-visible spectroscopy and fluorescence spectroscopy. The
    complexes exhibit Ru(II) metal centered emission at approximately 610 nm in acetonitrile solution at room temperature. DNA
    binding studies were carried out by UV-visible titration, luminescence titration and viscosity studies. The results indicated
    that [Ru(bpy)2
    (ddip)]2+ binds to CT-DNA by partial intercalation mode, while [Ru(bpy)2
    (dtip)]2+ and [Ru(bpy)2
    (dhip)]2+
    bind intercalatively via extended ligands.
    MeSH terms: Acetonitriles; DNA; Imidazoles; Intercalating Agents; Ligands; Magnetic Resonance Spectroscopy; Organometallic Compounds; Phenanthrolines; Ruthenium; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Temperature; Tomography, X-Ray Computed; Viscosity; 2,2'-Dipyridyl; Luminescence
  18. Mohammed Salisu Musa, Mohd Marsin Sanagi, Wan Aini Wan Ibrahim, Hadi Nur
    Sains Malaysiana, 2015;44:613-618.
    Carbon spheres (CSs) were synthesized from sucrose by hydrothermal reaction. The synthesized materials were further
    activated with potassium hydroxide (KOH) at different concentrations. The effects of KOH concentration on the surface area
    and morphology were investigated. The route for pore formation and structural deformation in carbon spheres during
    activation has been proposed and discussed based on micrographs and porosity trends. It was suggested that the pore
    formation and structural deformation phenomena were due to the intercalating power of energized K+ into the carbon.
    This work provides an insight of the pore formation in carbon spheres for the development of adsorbents as well as for
    the understanding of the structural deformation of such materials at higher KOH concentrations.
    MeSH terms: Carbon; Hydroxides; Intercalating Agents; Problem Solving; Sucrose; Porosity; Potassium Compounds
  19. Wan Fadhilah Khalik, Ong SA, Wong YS, Nik Athirah Yusoff, Fahmi Ridwan, Ho LN
    Sains Malaysiana, 2015;44:607-612.
    In this study, the photocatalytic degradation of batik wastewater in the presence of zinc oxide (ZnO) as photocatalyst was
    investigated. The effect of various operating parameters, such as pH of batik wastewater, catalyst dosage and aeration
    on the photocatalytic degradation process, was examined. The mineralization of batik wastewater was also evaluated
    through chemical oxygen demand analysis. The decolorization of batik wastewater was enhanced at acidic conditions
    (pH3) which was 88.2% after 10 h irradiated under solar light, meanwhile its mineralization was 286 mg/L after 12 h
    irradiation time. The data obtained for photocatalytic degradation of batik wastewater was well fitted with the LangmuirHinshelwood
    kinetic model. It can be concluded that batik wastewater could be decolorized and mineralized under solar
    light irradiation with presence of ZnO.
    MeSH terms: Catalysis; Kinetics; Sunlight; Zinc Oxide; Biological Oxygen Demand Analysis; Waste Water
  20. Norhayati Ibrahim, Norella Kong Chiew-Thong, Asmawati Desa, Rozmi Ismail
    Sains Malaysiana, 2015;44:599-605.
    This cross-sectional study examined the influence of illness perception of health-related quality of life (HRQoL) in end
    stage renal disease (ESRD) patients on either hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD).
    The Short Form-36 (SF-36) was used to measure HRQoL which comprised the Physical Component Summary (PCS) and
    Mental Component Summary (MCS). Illness perception was evaluated using Revised Illness Perception Questionnaire
    (IPQ-R). Both questionnaires were administered on 183 HD and 93 CAPD patients. The results showed that almost all
    HRQoL subscales except physical functioning and bodily pain were found to be significantly different between HD and
    CAPD patients. There are significant correlations between most components of illness perception with HRQoL. Significant
    illness perception predictors of PCS among HD patients were time line, consequences, cyclical and identity, whereas on
    CAPD patients were time line, illness coherence, emotional, cyclical and identity. Significant illness perception predictors
    of MCS among HD patients included time line, cyclical and identity and only time line was significant predictor of MCS on
    CAPD patients. These should be considered when developing intervention programmes to improve their HRQoL.
    MeSH terms: Cross-Sectional Studies; Renal Dialysis; Humans; Kidney Failure, Chronic; Pain; Perception; Peritoneal Dialysis, Continuous Ambulatory; Quality of Life; Surveys and Questionnaires
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