Browse publications by year: 2016

  1. Iskandar Shah Mohd Zawawi, Zarina Bibi Ibrahim
    Sains Malaysiana, 2016;45:989-998.
    In this paper, the fully implicit 2-point block backward differentiation formula and diagonally implicit 2-point block
    backward differentiation formula were developed under the interpretation of generalized differentiability concept for
    solving first order fuzzy differential equations. Some fuzzy initial value problems were tested in order to demonstrate the
    performance of the developed methods. The approximated solutions for both methods were in good agreement with the
    exact solutions. The numerical results showed that the diagonally implicit method outperforms the fully implicit method
    in term of accuracy.
    MeSH terms: Algorithms; Cell Differentiation; Numerical Analysis, Computer-Assisted
  2. Aziz AM, Omar MZ, Salleh MS
    Sains Malaysiana, 2016;45:977-987.
    Pemprosesan logam separa pepejal yang juga dikenali sebagai pembentukan-tikso merupakan suatu kaedah pemprosesan
    yang secara relatifnya adalah baharu jika dibandingkan dengan kaedah pemprosesan biasa seperti penuangan dan
    penempaan. Sebelum pembentukan-tikso dapat dilakukan, aloi berkenaan perlu melalui langkah awal persediaan iaitu
    dengan mengubah mikrostruktur asal berbentuk dendritik kepada bentuk hampir sfera. Ini diikuti dengan pemanasan
    semula ke julat suhu separa pejal (iaitu sekitar 30-50% cecair) dan seterusnya proses ubah bentuk ke dalam acuan
    menggunakan mesin penekanan hidraulik. Antara kaedah utama yang biasa digunakan bagi penyediaan bahan aloi
    ini adalah tuangan cerun penyejukan, pengadukan mekanik dan kaedah terma langsung. Kajian ini memberi tumpuan
    kepada evolusi mikrostruktur aloi aluminium A333 (Al-7.5Si-3.1Cu) daripada bentuk dendritik kepada hampir sfera
    sebagai persediaan untuk diproses melalui pembentukan-tikso kelak. Kaedah tuangan cerun penyejukan digunakan
    dalam kajian ini kerana kaedah ini diketahui berkesan tapi mudah digunakan. Nilai saiz ira dan faktor bentuk dianalisis
    berdasarkan kepada suhu tuangan dan panjang cerun penyejukan berbeza yang digunakan. Di samping itu, kaedah
    kalometri pengimbas perbezaan juga diguna pakai dalam mengenal pasti suhu sempadan pepejal dan sempadan cecair
    aloi ini. Saiz ira fasa pepejal α-Al paling kecil dan nilai faktor bentuk terbaik yang diperoleh dalam kajian ini berlaku
    pada suhu tuangan 620°C dan panjang cerun 300 mm, iaitu masing-masing pada 15.3 µm dan 0.54.
  3. Hazwan Halimoon, Abdul Rashid Hussain, Kouzani A, Muhd Nazrul Hisham Zainal Alam
    Sains Malaysiana, 2016;45:969-976.
    In this paper, a minibioreactor platform made of low cost polymers is presented. The minibioreactor prototype was designed
    as an alternative solution for carrying out microbial fermentation experiments in laboratory. The minibioreactor prototype
    has a working volume of 1.5 mL and was fabricated from poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane)
    (PDMS) polymers. Cell density was measured online whilst agitation rates and the temperature of the reactor content
    can be tightly controlled to desired set-point values. As proof-of-concept, various S. cerevisae fermentation experiments
    were conducted. In every experiment, the minibioreactor operated stably for the entire length of operation which was
    nearly 40 h with very minimal volume loss i.e. about 2.8 µL·h-1 at 37ºC. The minibioreactor has the maximum oxygen
    transfer rate (OTR) of 16.6 mmol·L-1·h-1 under the agitation rate of 300 rpm. Under these conditions, cell specific growth
    rate as high as 0.291 h-1 was obtained. The experimental data in the minibioreactor operation was also reproducible
    using shake flask where similar growth profiles were attained under a similar growth conditions.
  4. Chuah TS, Norhafizah MZ, Naimah AH, Ismail BS
    Sains Malaysiana, 2016;45:963-967.
    The allelochemical 2,4-di-tert-butylphenol (2,4-DTBP) is one of the natural compounds present in medicinal plants.
    This compound has been reported to possess herbicidal properties. However, its effect on weed growth parameters is
    unknown for it to be utilized in weed management. Hence, the herbicidal potential of the allelochemical 2,4-DTBP on the
    root and leaf tissues of the grassy weed, Leptochloa chinensis (L.) Nees and the broadleaf weed, Hedyotis verticillata
    (L.) Lam was investigated. After 2,4-DTBP treatment, both bioassay species had abnormal and much shorter root hairs
    compared to those of untreated plants. The roots of H. verticillata were severely damaged with the root nodes turned
    brown. The phytotoxic effect of 2,4-DTBP on L. chinensis and H. verticillata became apparent at seven days and 14 days
    after treatment with symptoms of lamina wilting and necrosis, respectively. These results demonstrated that 2,4-DTBP
    could be used as a natural herbicide for the control of L. chinensis and H. verticillata.
    MeSH terms: Biological Assay; Poaceae; Hair; Herbicides; Phenols; Pheromones; Plants, Medicinal; Hedyotis
  5. Soontornchaiboon W, Kim SM, Pawongrat R
    Sains Malaysiana, 2016;45:955-962.
    The effects of six pretreatments of five agricultural wastes (corn cob, pineapple waste, bagasse, rice straw and water
    hyacinth) on the chemical composition and total reducing sugar yield were investigated. Six pretreatments were: 1% NaOH
    with ultrasound for 60 min; 1% NaOH with ultrasound 100% duty; 2% NaOH with ultrasound for 60 min; 2% NaOH
    with ultrasound 100% duty cycle; 1% NaOH by standing in the oven at 60°C for 90 min; and 2% NaOH by standing
    in the oven at 60°C for 90 min. Among them, the highest cellulose content of 55.15% was obtained from bagasse by
    pretreating with 1% NaOH with ultrasound 100% duty cycle. It subsequently yielded the highest total reducing sugar of
    36.21% (36.21 g reducing sugar/100 g substrate). The lignin content of all samples significantly decreased, but ultrasonic
    pretreatment increased the cellulose content. However, the best pretreatment method for each sample was different. Based
    on SEM analysis, the morphologies of all samples were changed after pretreatment. In addition, the increase of enzyme
    loading from 250 to 550 CMC U/g biomass led to more than 20% increase in the total reducing sugar. It was found that
    the higher enzyme loading (700 CMC U/g dried biomass) did not improve the total reducing sugar for all samples.
  6. Siti Afida I., Razmah G., Zulina A. M.
    Sains Malaysiana, 2016;45:949-954.
    The concern on the widespread use of surfactants is increasing worldwide as they can be potential toxicants by polluting
    the environment, with the damage formed depending on their exposure and persistence in the ecosystem. This paper
    was intended to evaluate the biodegradability of palm-based surfactant, MES, in order to establish their environmental
    friendliness. The respirometric method was used to monitor the biodegradation of various homologues of MES over 28
    days as described in the OECD 301F Manometric respirometry test method. The results showed all the MES homologues
    tested were readily biodegradable with percentage of biodegradation achieved for C12, C14 and C16 MES was 73%
    within 6 days, 66% within 8 days and 63% within 16 days, respectively, while linear alkylbenzene sulphonates (LAS)
    sample 60% biodegraded within 8 days. From the results, it can be concluded that the longer the carbon chain length, the
    lower is the biodegradability of MES as the microorganisms took longer time to degrade a longer chain surfactant. Other
    than that, the presence of aromatic structure in LAS may also extend the biodegradation process. The use of palm-based
    surfactant, i.e. MES, is more environmental friendly and can be used as an alternative to petroleum-based surfactant to
    reduce adverse environmental effects of surfactant on ecosystem.
    MeSH terms: Biodegradation, Environmental; Carbon; Petroleum; Surface-Active Agents; Alkanesulfonic Acids; Ecosystem; Organisation for Economic Co-Operation and Development
  7. Cheong AT, Lee PY, Ng CJ, Lee YK, Ong TA, Abdullah KL, et al.
    Sains Malaysiana, 2016;45:941-947.
    There are many treatment options for localized prostate cancer, and there is clinical equipoise in relation to the treatment outcomes. This study aimed to explore doctors’ approaches to decision support in counseling patients with localized prostate cancer in a country with a less established system of support and care delivery for cancer treatment. Four in-depth
    interviews and three focus group discussions were conducted with seven government policy makers/consultant urologists, three oncologists, four private urologists and six urology trainees in Malaysia between 2012 and 2013. Doctors facilitated the treatment decision by explaining about the disease and the treatment options, which included monitoring,
    side effects and complications of each treatment option. Paper-based (charts and diagram drawings) or electronic (ipad apps and websites) illustrations and physical models were used as patient education aids. Further reading materials and websites links were often provided to patients. Patients were given time till subsequent follow up to decide on the
    treatment and family involvement was encouraged. Referral to other healthcare professionals (oncologist, radiotherapist or other urologist) for second opinion was offered to the patients. The doctors would recommend patients to speak to prostate cancer survivors for peer support but official support groups were not easily accessible. This study highlighted
    a multi-faceted approach to support patients with localized prostate cancer in making a treatment decision. It not only involved the doctors (urologist or oncologist) themselves, but also empowered the patients and their social network to support the decision making process.
    MeSH terms: Adult; Health Personnel; Hospitals; Humans; Malaysia; Prostatic Neoplasms*; Interview; Qualitative Research; Urologists*
  8. Roh JM, Lee JH, Lee SS, Bahk JD, Kim TW, Kim Is, et al.
    Sains Malaysiana, 2016;45:933-940.
    Salmonella typhimurium MMP13 harboring pMMP99, a recombinant plasmid derived by cloning a ghost cassette into
    T-vector, were employed for production of ghost cells. Growth of MMP13 (pMMP99) showed an initial increase after a
    shift in temperature from 28 to 42°C, and then decreased gradually with ghost formation being complete within 3 h.
    Ghost yield of MMP13 (pMMP99) were 99.99% less than 104 CFU/mL. MMP13 (pMMP101-1) showed a ghost yield similar
    to MMP13 (pMMP99). Immune responses of BALB/c mice against ghost cells originated from MMP13 (pMMP101-1) were
    assessed by measuring total IgG, IgG1, IgG2a, and secretory IgA levels in each sample. Levels of total IgG, IgG1 and
    IgG2a and vaginal IgA, increased abruptly after 4 weeks post vaccination, whereas the fecal IgA level did not induce
    significant change. Splenocyte proliferation was observed at the cellular level owing to stimulation of ghost cells. Ghost
    vaccination protected 25-59% of mice against wild-type S. typhimurium more than those of controls.
  9. Kuek FWI, Aazani Mujahid, Lim Pt, Leaw Cp, Müller M
    Sains Malaysiana, 2016;45:915-931.
    Little is known about the diversity and roles of microbial communities in the South China Sea, especially the eastern
    region. This study aimed to expand our knowledge on the diversity of these communities in Malaysian waters, as well as
    their potential involvement in the breakdown or osmoregulation of dimethylsulphoniopropionate (DMSP). Water samples
    were collected during local cruises (Kuching, Kota Kinabalu, and Semporna) from the SHIVA expedition and the diversity
    of bacterial communities were analysed through the isolation and identification of 176 strains of cultured bacteria. The
    bacteria were further screened for the existence of two key genes (dmdA, dddP) which were involved in competing,
    enzymatically-mediated DMSP degradation pathways. The composition of bacterial communities in the three areas varied
    and changes were mirrored in physico-chemical parameters. Riverine input was highest in Kuching, which was mirrored
    by dominance of potentially pathogenic Vibrio sp., whereas the Kota Kinabalu community was more indicative of an
    open ocean environment. Isolates obtained from Kota Kinabalu and Semporna showed that the communities in these
    areas have potential roles in bioremediation, nitrogen fixing and sulphate reduction. Bacteria isolated from Kuching
    displayed the highest abundance (44%) of both DMSP-degrading genes, while the bacterial community in Kota Kinabalu
    had the highest percentage (28%) of dmdA gene occurrence and the dddP gene responsible for DMS production was
    most abundant (33%) within the community in Semporna. To the best of our knowledge, this is the first study looking at
    the diversity of culturable bacteria in coastal waters of East Malaysia and also their potential roles in the DMS(P) cycle.
    MeSH terms: Biodegradation, Environmental; China; Expeditions; Malaysia; Nitrogen; Oceans and Seas; Sulfates; Sulfonium Compounds; Vibrio; Osmoregulation
  10. Banerjee G, Ray AK, Kumar R
    Sains Malaysiana, 2016;45:909-914.
    Antibiotic resistant bacterial population is a great threat for human as well as for other domestic animals. Unscientific
    use of antibiotics in clinical sectors create a selective pressure on bacteria that make bacteria resistant to a wide range
    of drugs. The current finding demonstrated the isolation and characterization of multi antibiotics resistant bacterial
    species from oil contaminated soil and its lateral gene transfer efficiency at different temperature. Among six bacterial
    isolates, the strain OD1 showed highest antibiotic resistant capacity was selected for further studies. Morphological,
    biochemical and 16S rDNA sequence analysis confirmed the bacterial strains as Alcaligenes faecalis strain OD1. It was
    recorded that antibiotics resistant gene transfer was highly dependent on temperature and showed maximum transfer
    efficiency at 25°C (9.6 ×10-6).
  11. Parvin S, Hossain MY, Rahma MM, Rahman MS, Ahmed ZF, Ohtomi J, et al.
    Sains Malaysiana, 2016;45:899-907.
    The threatened indigenous small fish, Mystus vittatus (Bloch 1794) is a commercially important fish of Bangladesh.
    The present study describes the fecundity and its relationships with some of the morphometrics and condition factors
    (Fulton’s, KF; Relative weight, WR) of M. vittatus. A total of 50 matured female M. vittatus were collected using the cast
    net from the Padma River during May-July, 2012. Total fecundity (FT
    ) of each female was calculated as the number
    of oocytes found in each ovary, whereas relative fecundity (FR) was the number of oocytes per gram of fish weight.
    The total length (TL) ranged from 8.21 to 12.36 cm (10.60±1.08 cm) and the body weight (BW) varied between 6.0 and
    21.65 g (14.08±4.15 g). The FT
    ranged from 3256 to 22549 with a mean value of 13064.50±4920 while the FR ranged
    from 472 to 1648 oocytes per gram of female, with a mean of 929±245. Significant and strong relationships were found
    between FT vs. TL (r
    2 = 0.63; p<0.001), FT vs. BW (r2 = 0.61; p<0.001), FT vs. OW (r
    2 = 0.89; p<0.001) and FT vs. GSI (rs =
    0.67; p<0.001), but insignificant relationships were recorded for FT vs. KF (rs = 0.11; p = 0.452), FT vs.WR (rs
    = 0.001;
    p = 0.997). The information provided in this study will help initiating sustainable management and conservation of the
    threatened M. vittatus in the region.
  12. Nurul Amin M, Babatunde TA, Ihab MMM, Usman BI, Ara R
    Sains Malaysiana, 2016;45:891-898.
    Cobia Rachycentron canadum, is one of the emerging aquaculture species but is usually a non-target resource in fisheries
    industry and within Malaysia, their landings are among the highest worldwide. Identification of stocks with unique
    morphological characters is important for effective management and sustainable utilization. Morphometric variations
    among three different cobia populations from Kedah, Terengganu and Johor were studied. All the morphometric
    characteristics varied among the three populations as all the elements of the first Eigen vector were positive. Discriminant
    analysis suggested that head depth (HD) and maximum body depth, (MaxD) were the most varied among the populations.
    Cobia populations from Kedah and Johor were in a single cluster in the dendrogram with a 63.69% similarity while
    Terengganu was in another cluster with a similarity of 8.01% from Kedah and Johor. The differences in the observed
    morphometry may be resulted from different trophic activities and/or habitat productiveness explored by each of the
    populations
    MeSH terms: Animals; Disease Vectors; Fisheries; Malaysia; Perciformes; Ecosystem; Aquaculture
  13. Muzzazinah, Nunik Sri Ariyanti, Tatik Chikmawati
    Sains Malaysiana, 2016;45:883-890.
    A total of 9 species of Indigofera have been identified on the Islands of Java and Madura. Only one species has been
    utilized by batik makers and weavers as a natural dye, while the other 8 species are of unknown potential as natural
    dyes. This study seeks to demonstrate the correlation between morphological characteristics and the level and quality of
    indicant compound, in order to assist batik producers and weavers in determining the species that can be used as dyestuff.
    The potential blue colour dyestuff yield of Indigofera was determined by leaf immersion, followed by quantitative and
    qualitative examination of the indicant present. Morphological characteristics were then analysed to identify those that
    correlated with the presence of indicant. The indicant differences were analysed using SPSS; the relationship between the
    characteristics was analyzed by Pearson correlation and logistic regression. Four species, namely I. tinctoria, I. arrecta, I.
    suffruticosa and I. longiracemosa contained indigo. The colour produced by indigo dye obtained from these four species
    of Indigofera had a ‘4–5’ value of colour change and colour staining in tests involving washing, sweat, bright light and
    heat stress. This value meets the ‘good quality’ standard of the Indonesian National Standards (SNI). I. suffruticosa has
    the highest indicant content at 1.4 g/kg, followed by I. tinctoria, I. arrecta, and I. longiracemosa with 0.414, 0.13, and
    0.038 g/kg, respectively. The colour of upper and lower dried foliages were correlated to potential indigo dye producers.
  14. Upadhya RK
    Sains Malaysiana, 2016;45:879-882.
    he deficiency of oxygen in water during submergence is one of the frequently perceived environmental factors that limits
    or hampers production of the rice cultivation. Rice plants comprise of elongated submerged tissues that help to bear with
    the rise of water level in natural location. This characteristic helps the plant to deal with flooding stress. The mechanism
    on flooding tolerance and adaptation mostly includes the physiological changes, one of which is the shortened growth
    of elongation towards keeping the carbohydrates and energy for production of the antioxidant regulations in rice plants.
    Furthermore, molecular studies and gene cloning might help suggest a better understanding of means and adaptations
    built-up by rice plants in order to stay alive and to remain active during flooding stress, might help to focus on some
    novel approaches to the up gradation as well as improvement on the natural cultivation of rice plants.
    MeSH terms: Acclimatization; Adaptation, Physiological; Animals; Ursidae; Carbohydrates; Oxygen; Oryza; Water; Life; Floods
  15. Soon TK, Julian Ransangan
    Sains Malaysiana, 2016;45:865-877.
    Marudu Bay, north coast of Sabah is characterized with mesotrophic water body and typical environmental parameters
    throughout the year. The current study was undertaken to evaluate the effect of environmental parameters and nutrients
    in mesotrophic water on the occurrence and distribution of potentially harmful phytoplankton species. The samplings
    were conducted over a period of thirteen months, covering southwest monsoon (SWM), inter-monsoon (IM), and northeast
    monsoon (NEM), at ten stations throughout the bay. Physical parameters (temperature, salinity, pH, dissolved oxygen,
    current speed and secchi depth), biological parameters (cell densities of phytoplankton) and chemical parameters
    (phosphate, nitrate, silicate and ammonia) were examined. The results indicated at least eight potentially harmful
    phytoplankton species (Dinophysis caudata, D. miles, Ceratium furca, C. fursus, Prorocentrum micans, P. sigmoides, P.
    triestinum and Pseudo-nitzschia sp.) were detected in north coast of Sabah. However, the potentially harmful phytoplankton
    species contributed only about 1.3% of the total phytoplankton community. Under nutrient deprivation conditions, the
    potentially harmful phytoplankton species distribution was mainly influenced by the ability to utilize other nitrogen
    sources, cell mobility and toleration to low nutrients environments.
    MeSH terms: Ammonia; Cell Count; Dinoflagellida; Malaysia; Nitrates; Nitrogen; Oxygen; Phosphates; Phytoplankton; Temperature; Water; Diatoms; Silicates; Salinity; Bays
  16. Fawaz Al-badaii, Azhar Abdul Halim, Mohammad Shuhaimi-othman
    Sains Malaysiana, 2016;45:841-852.
    The study to determine the concentrations of dissolved heavy metals in the Sungai Semenyih and to use the environmetric
    methods to evaluate the influence of different pollution sources on heavy metals concentrations was carried out. Cluster
    analysis (CA) classified 8 sampling stations into two clusters based on the similarity of sampling stations characteristics,
    cluster 1 included stations 1, 2, 3 and 4 (low pollution area), whereas cluster 2 comprised of stations 5, 6, 7 and 8
    (high pollution area). Principal component analysis (PCA) of the two datasets yield two factors for low pollution area
    and three factors for the high pollution area at Eigenvalues >1, representing 92.544% and 100% of the total variance
    in each heavy metals data sets and allowed to gather selected heavy metals based on the anthropogenic and lithologic
    sources of contamination.
    MeSH terms: Environmental Pollution; Cluster Analysis; Metals, Heavy; Principal Component Analysis
  17. Zainuddin N, Saleh H, Hashim I, Roslan R
    Sains Malaysiana, 2016;45:315-321.
    Effects of radiation on free convection about a heated horizontal circular cylinder in the presence of heat generation is investigated numerically. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equations are transformed into dimensionless non-linear partial differential equations and solved by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determined the effects of radiation parameter, heat generation parameter, and the Prandtl number, on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of and are shown graphically.
    MeSH terms: Body Temperature Regulation; Clothing; Hot Temperature; Temperature; Friction; Convection
  18. Waleeda Swaidan, Amran Hussin
    Sains Malaysiana, 2016;45:305-313.
    A new numerical method was proposed in this paper to address the nonlinear quadratic optimal control problems, with state and control inequality constraints. This method used the quasilinearization technique and Haar wavelet operational matrix to convert the nonlinear optimal control problem into a sequence of quadratic programming problems. The inequality constraints for trajectory variables were transformed into quadratic programming constraints using the Haar wavelet collocation method. The proposed method was applied to optimize the control of the multi-item inventory model with linear demand rates. By enhancing the resolution of the Haar wavelet, we can improve the accuracy of the states, controls and cost. Simulation results were also compared with other researchers' work.
    MeSH terms: Income; Socioeconomic Factors; Neural Networks (Computer)
  19. Muhammad Khairul Anuar Mohamed, Nor Aida Zuraimi Md Noar, Mohd Zuki Salleh, Anuar Ishak
    Sains Malaysiana, 2016;45:189-296.
    In this paper, the problem of free convection boundary layer flow on a horizontal circular cylinder in a nanofluid with viscous dissipation and constant wall temperature is investigated. The transformed boundary layer equations are solved numerically using finite difference scheme namely the Keller-box method. Numerical solutions were obtained for the reduced skin friction coefficient, Nusselt number and Sherwood number as well as the velocity and temperature profiles.The features of the flow and heat transfer characteristics for various values of the Brownian motion parameter, thermophoresis parameter, Lewis number and Eckert number were analyzed and discussed.
    MeSH terms: Hot Temperature; Motion; Temperature; Viscosity; Friction; Convection; Physical Phenomena
  20. Ebenezer Akin Oluwasola, Md. Maniruzzaman A. Aziz, Naquiddin M. Warid M, Mohd Rosli Hainin
    Sains Malaysiana, 2016;45:278-287.
    This study focuses on the potential of electric arc furnace (EAF) steel slag and copper mine tailings as asphalt paving materials with respect to issues of volumetric properties and leaching. In this study, four different asphalt mixes were investigated; each contained EAF steel slag and copper mine tailings of various proportions. Apart from the microstructure analysis of the materials, a toxicity characteristics leaching procedure (TCLP) test was conducted on both the mixes and the aggregates. All the mixes were evaluated by the following parameters: Voids in the mineral aggregates (VMA), voids in total mix (VTM), voids filled with asphalt (VFA), Marshall stability and flow and specific gravity. F-test ANNOVA was used to evaluate the degree of significance of the mixes with each of the evaluated standards. It was observed that the mixes containing either EAF steel slag or copper mine tailings or both gave better results than the control mix. In terms of the TCLP test, none of the detected hazardous elements exceeded the standard limits, which indicates the possibility of using them as construction materials.
    MeSH terms: Construction Materials; Copper; Hydrocarbons; Minerals; Specific Gravity; Steel; Toxicity Tests
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