Displaying publications 1 - 20 of 204 in total

  1. Roslan, M.H., Azis, N., Jasni, J., Ibrahim, Z.
    Top-Oil Temperature (TOT) is one of the basic components to estimate the Hot-Spot temperature (HST) of the transformers. This paper presents an alternative TOT model based on the heat transfer theory that utilises Nonlinear Thermal Resistance (NTR) and Lumped Capacitance (LC) approaches. It is applied in a thermal-electrical analogy and the heat transfer equivalent equation is determined. This model is tested on a measured TOT of 250 MVA ONAF and 400 MVA ONAF transformers obtained from IEC 60076-7 and previous research. A comparison of TOT is carried out with the existing models IEC 60076-7 exponential and IEEE Loading Guide clause 7 methods. It is found that the thermal model based on the NTR and LC approach could determine the measured TOT closer than the existing methods available in the standards.
  2. Mohamed, S.B., Mohamad, W.N.F.W., Yew, B.S., Ibrahim, Z., Musanih, M.R., Zitoune, R., et al.
    The use of hybrid composite has increased due to their special mechanical and physical properties.
    However, machining of composite materials is extremely difficult due to non-homogeneous,
    anisotropic and highly abrasive characteristics. The performance of machined surface quality of
    CFRP/Al2024 was described using two level full factorial methodology. Trimming test was performed
    under dry conditions using 6mm diameter of burr tools end mills. The factors investigated were spindle
    speed(N), feed rate(fr) and depth of cut(dc), furthermore Ra CFRP and Ra Al2024 were the response
    variables. This work aims to minimize the machined surface quality of CFRP/Al2024 between 1µm to
    2µm. The finding of this empirical study has shown that, the best estimated value of fr should be 500
    mm/min to 530 mm/min, N is between and 2313.870 rpm to 2336.042 rpm. For both response spindle
    speed is the most significant effect followed by Feed rate and Depth of Cut.
  3. Chew PC, Julaihi B, Ibrahim Z
    Malays Orthop J, 2013 Mar;7(1):70-3.
    PMID: 25722811 MyJurnal DOI: 10.5704/MOJ.1303.002
    Spontaneous atypical fractures of the femur have been reported in patients on long-term antiresorptive bisphosphonate therapy. Here, we report a case of subtrochanteric stress fracture in a seventy-year-old female patient on long-term alendronate therapy, and accompanying management challenges. Potential measures to prevent this complication of antiresorptive treatment for osteoporosis include the following: setting strict criteria for prescribing antiresorptive therapy, limiting the duration of continuous antiresorptive therapy, and increasing the use of bone anabolic agents.
  4. Cheong I, Lim A, Lee C, Ibrahim Z, Sarvanathan K
    Med J Malaysia, 1997 Dec;52(4):313-7.
    PMID: 10968106
    Between 1987 to 1995, a total of 334 patients infected with HIV were treated at the Hospital Kuala Lumpur. There were 159 Malays, 108 Chinese, 64 Indians, and 3 from other ethnic groups. Three hundred and twenty-one (96.1%) of these individuals were males and 262 (65.9%) were between the ages of 26-45 years. Intravenous drug users made up 77% (256) of the attributable risk behaviour from the group although many of them also had added risk behaviours like heterosexual activity with multiple partners (50 patients), tattoos (7 patients), homosexual practice (4 patients) and previous transfusions (3 patients). The others acquired their infection through heterosexual promiscuity (59 patients), homo/bisexual activity (7 patients), previous transfusion (5 patients) and tattoos (1 patient). Sixty-six patients (all males) had since progressed to full blown AIDS and 10 have died. The two commonest AIDS-defining events were tuberculosis infection and Pneumocystic carinii pneumonia occurring in 37 (56%) and 15 (22.7%) of patients respectively. Forty-one patients with AIDS presented for the first time with their AIDS-defining infections. The mean CD4 count of the patients when they progressed to AIDS was 130/mm3. The mean time for progression from "known" seropositivity to AIDS was 2.42 years. These results suggest that Malaysians infected with HIV are not coming forward for treatment until they are in the advanced stage of the disease.
  5. Murugesu, S., Khatib, A., Ibrahim, Z., Ahmed, Q. U., Uzir, B.F., Nik-Yusoff, N.I., et al.
    Clinacanthus nutans (Acanthaceae) is a local plant consumed as tisane in Indonesia and ‘ulam’ in Malaysia. This plant has been claimed for its ability to prevent many diseases including diabetes. However, the scientific proof on this claim is still lacking. Therefore, the present work study was designed to evaluate the antidiabetic potential and antioxidant capacity of C. nutans leaves extracts using in vitro bioassay tests. The 80% methanolic crude extract of this plant was further partitioned using different polarity solvents namely hexane, hexane:ethyl acetate (1:1, v/v), ethyl acetate, ethyl acetate:methanol (1:1, v/v), and methanol. All the sub-fractions were analysed for antioxidant effect via 2, 2-diphenyl-2-picrylhydrazil (DPPH) scavenging activity, ferric reducing power (FRAP) and xanthine oxidase (XO) assays followed by antidiabetic evaluation via α-glucosidase and dipeptidyl peptidase-IV (DPP-IV) inhibitory assays and glucose uptake experiment. The ethyl acetate fraction showed a good antioxidant potential while the hexane fraction exhibited high α-glucosidase and DPP-IV enzyme inhibition. The hexane fraction also improved glucose uptake in a dose-dependent manner. The present work thus provides an informative data on the potential of C. nutans to be developed as a functional food in preventing diabetes.
  6. Ibrahim Z, Amin MF, Yahya A, Aris A, Muda K
    Water Sci Technol, 2010;61(5):1279-88.
    PMID: 20220250 DOI: 10.2166/wst.2010.021
    Textile wastewater, one of the most polluted industrial effluents, generally contains substantial amount of dyes and chemicals that will cause increase in the COD, colour and toxicity of receiving water bodies if not properly treated. Current treatment methods include chemical and biological processes; the efficiency of the biological treatment method however, remains uncertain since the discharged effluent is still highly coloured. In this study, granules consisting mixed culture of decolourising bacteria were developed and the physical and morphological characteristics were determined. After the sixth week of development, the granules were 3-10 mm in diameter, having good settling property with settling velocity of 70 m/h, sludge volume index (SVI) of 90 to 130 mL/g, integrity coefficient of 3.7, and density of 66 g/l. Their abilities to treat sterilised raw textile wastewater were evaluated based on the removal efficiencies of COD (initial ranging from 200 to 3,000 mg/L), colour (initial ranging from 450 to 2000 ADMI) of sterilised raw textile wastewater with pH from 6.8 to 9.4. Using a sequential anaerobic-aerobic treatment cycle with hydraulic retention time (HRT) of 24 h, maximum removal of colour and COD achieved was 90% and 80%, respectively.
  7. Ibrahim Z, Tsuboi Y, Ono O
    IEEE Trans Nanobioscience, 2006 Jun;5(2):103-9.
    PMID: 16805106
    Previously, direct-proportional length-based DNA computing (DPLB-DNAC) for solving weighted graph problems has been reported. The proposed DPLB-DNAC has been successfully applied to solve the shortest path problem, which is an instance of weighted graph problems. The design and development of DPLB-DNAC is important in order to extend the capability of DNA computing for solving numerical optimization problem. According to DPLB-DNAC, after the initial pool generation, the initial solution is subjected to amplification by polymerase chain reaction and, finally, the output of the computation is visualized by gel electrophoresis. In this paper, however, we give more attention to the initial pool generation of DPLB-DNAC. For this purpose, two kinds of initial pool generation methods, which are generally used for solving weighted graph problems, are evaluated. Those methods are hybridization-ligation and parallel overlap assembly (POA). It is found that for DPLB-DNAC, POA is better than that of the hybridization-ligation method, in terms of population size, generation time, material usage, and efficiency, as supported by the results of actual experiments.
  8. Zulkarnaen M, Pan K, Shanmugam P, Ibrahim Z, Chan W
    Malays Orthop J, 2012 Mar;6(1):49-52.
    PMID: 25279044 MyJurnal DOI: 10.5704/MOJ.1203.003
    Synovial sarcoma is primarily a soft tissue malignancy that most often affects adolescents and young adults. It very rarely presents as a primary bone tumour and has only been reported in nine other cases to date. We report a case of primary synovial sarcoma arising from the proximal femur in a 57-year-old man.
  9. Gan HM, Shahir S, Ibrahim Z, Yahya A
    Chemosphere, 2011 Jan;82(4):507-13.
    PMID: 21094980 DOI: 10.1016/j.chemosphere.2010.10.094
    A co-culture consisting of Hydrogenophaga sp. PBC and Ralstonia sp. PBA, isolated from textile wastewater treatment plant could tolerate up to 100 mM 4-aminobenzenesulfonate (4-ABS) and utilize it as sole carbon, nitrogen and sulfur source under aerobic condition. The biodegradation of 4-ABS resulted in the release of nitrogen and sulfur in the form of ammonium and sulfate respectively. Ninety-eight percent removal of chemical oxygen demand attributed to 20 mM of 4-ABS in cell-free supernatant could be achieved after 118 h. Effective biodegradation of 4-ABS occurred at pH ranging from 6 to 8. During batch culture with 4-ABS as sole carbon and nitrogen source, the ratio of strain PBA to PBC was dynamic and a critical concentration of strain PBA has to be reached in order to enable effective biodegradation of 4-ABS. Haldane inhibition model was used to fit the degradation rate at different initial concentrations and the parameters μ(max), K(s) and K(i) were determined to be 0.13 h⁻¹, 1.3 mM and 42 mM respectively. HPLC analyses revealed traced accumulation of 4-sulfocatechol and at least four unidentified metabolites during biodegradation. This is the first study to report on the characterization of 4-ABS-degrading bacterial consortium that was isolated from textile wastewater treatment plant.
  10. Gan HM, Ibrahim Z, Shahir S, Yahya A
    FEMS Microbiol Lett, 2011 May;318(2):108-14.
    PMID: 21323982 DOI: 10.1111/j.1574-6968.2011.02245.x
    Genes involved in the 4-aminobenzenesulfonate (4-ABS) degradation pathway of Hydrogenophaga sp. PBC were identified using transposon mutagenesis. The screening of 10,000 mutants for incomplete 4-ABS biotransformation identified four mutants with single transposon insertion. Genes with insertions that impaired the ability to utilize 4-ABS for growth included (1) 4-sulfocatechol 1,2-dioxygenase β-subunit (pcaH2) and 3-sulfomuconate cycloisomerase involved in the modified β-ketoadipate pathway; (2) 4-aminobenzenesulfonate 3,4-dioxygenase component (sadA) involved in aromatic ring hydroxylation; and (3) transposase gene homolog with a putative cis-diol dehydrogenase gene located downstream. The pcaH2 mutant strain accumulated brown metabolite during growth on 4-ABS which was identified as 4-sulfocatechol through thin layer chromatography and HPLC analyses. Supplementation of wild-type sadA gene in trans restored the 4-ABS degradation ability of the sadA mutant, thus supporting the annotation of its disrupted gene.
  11. Sinniah B, Hassan A KR, Sabaridah I, Soe MM, Ibrahim Z, Ali O
    Trop Biomed, 2014 Jun;31(2):190-206.
    PMID: 25134888 MyJurnal
    Intestinal parasitic infections are among the most common diseases affecting mankind causing major public health problems to billions of people living in developing countries. The aim of this study is to determine the prevalence of intestinal parasites in various communities residing in different habitats in Malaysia and compare the findings with 101 studies conducted over the past 42 years (1970-2013). A cross-sectional study design was conducted with the aid of a questionnaire to collect relevant information about the study population. Faecal samples were examined using the direct smear and formal ether sedimentation techniques. A total of 342 children were examined amongst whom 24.6% were positive for intestinal parasitic infections. Results showed that 32.3% of rural children, 20.6% of urban squatters and 5.4% of children from flats were positive for one or more parasites. The most common parasite encountered was Trichuris trichiura (20.2%) followed by Ascaris lumbricoides (10.5%) and hookworm (6.7%). No case of hookworm was reported in urban children whereas 12.2% of rural children were positive. The most common protozoan parasite detected was Entamoeba coli (3.2%) followed by Giardia intestinalis (1.8%), Entamoeba histolytica (1.8%) and Blastocystis hominis (1.2%). Nearly one-fifth (18.4%) of the children had single infection followed by double (12.0%) and triple infections (1.2%). Orang Asli (indigenous) children (44.3%) had the highest infection rate followed by Indians (20.2%), Malays (14.0%) and Chinese (11.9%). Twenty-eight studies carried out on plantation communities with regards to intestinal parasitic infections in Malaysia from 1970 to 2013 showed a steady decline in the prevalence rate ranging from 95.0% in the seventies to 37.0 % in 2012. Intestinal parasitic infections were more common in Orang Asli communities with prevalence ranging from over 90% in the seventies and fluctuating below 70% in most studies between 2000 to 2013 except for two studies that showed a prevalence of 98.2% and 100%. The prevalence rate among urban squatters, urban residents and those living in flats showed dramatic decrease in prevalence rate.
  12. Najib MZM, Salmiati, Ujang Z, Salim MR, Ibrahim Z, Muda K
    Bioresour Technol, 2016 Dec;221:157-164.
    PMID: 27639234 DOI: 10.1016/j.biortech.2016.08.119
    The developed microbial granules containing photosynthetic pigments had successfully achieved approximately 18-21% of carbon dioxide (CO2) removal in POME for one complete SBR cycle. Also, the granules had reached CO2 removal at 15-29% within 24h and removal of 25% after 5 days. Both results were inconsistent possibly due to the slow mass transfer rate of CO2 from gas to liquid as well as the simultaneous effect of CO2 production and respiration among the microbes. Furthermore, results showed the removal of CO2 from air increases proportionally with the CO2 removed in liquid. The CO2 biofixation of granules attained was approximately 0.23g/L/day for a week. Using the regression model, the removal of CO2 between liquid and gas, CO2 biofixation rate were highly correlated with the treatment time. A statistically significant relationship was obtained between CO2 concentration in liquid, biomass productivity and treatment time for the CO2 biofixation rate of the granules.
  13. Mehrabi MH, Suhatril M, Ibrahim Z, Ghodsi SS, Khatibi H
    PLoS One, 2017;12(6):e0176480.
    PMID: 28570657 DOI: 10.1371/journal.pone.0176480
    Conventional seismic rehabilitation methods may not be suitable for some buildings owing to their high cost and time-consuming foundation work. In recent years, viscoelastic dampers (VEDs) have been widely used in many mid- and high-rise buildings. This study introduces a viscoelastic passive control system called rotary rubber braced damper (RRBD). The RRBD is an economical, lightweight, and easy-to-assemble device. A finite element model considering nonlinearity, large deformation, and material damage is developed to conduct a parametric study on different damper sizes under pushover cyclic loading. The fundamental characteristics of this VED system are clarified by analyzing building structures under cyclic loading. The result show excellent energy absorption and stable hysteresis loops in all specimens. Additionally, by using a sinusoidal shaking table test, the effectiveness of the RRBD to manage the response displacement and acceleration of steel frames is considered. The RRBD functioned at early stages of lateral displacement, indicating that the system is effective for all levels of vibration. Moreover, the proposed damper shows significantly better performance in terms of the column compression force resulting from the brace action compared to chevron bracing (CB).
  14. Javanmardi A, Ibrahim Z, Ghaedi K, Khan NB, Benisi Ghadim H
    PLoS One, 2018;13(7):e0200482.
    PMID: 30059506 DOI: 10.1371/journal.pone.0200482
    This paper investigated the seismic retrofitting of an existing cable-stayed bridge through the use of a seismic isolation system. The bridge is situated in a high seismic zone. During the Saguenay earthquake 1988, one of the anchorage plates of the bridge supports failed. Herein, several configurations of seismic isolation system were considered to identify an appropriate solution for the seismic retrofitting of the bridge in both the longitudinal and transverse directions. A three-dimensional model of the bridge was created, and its seismic behavior studied through nonlinear dynamic time-history analysis. The comparative performance study among the five retrofitting configurations showed that the partial seismic isolation of the bridge led to an enhancement of the seismic response of the bridge in one direction only. However, the overall seismic response of the cable-stayed bridge substantially improved in the longitudinal and transverse directions in cases where the isolation systems were utilized between the supports and the deck-tower connection of the bridge.
  15. Mesbah SF, Sulaiman N, Shariff ZM, Ibrahim Z
    PMID: 32365772 DOI: 10.3390/ijerph17093118
    With the aging of the population worldwide, there is an increasing concern for the mental health status as well as physical health. Depression is a common mental health problem among the elderly populations. Since the elderly are susceptible to food insecurity, this cross-sectional study is aimed to determine an association between food insecurity and depression among elderly people. A total of 220 elderly people- aged 60 years and above, residing in the Petaling district of Selangor, were included in this study. Face-to-face interviews were conducted to obtain the pertinent information on demographic background, food security status (six items USDA FSSM), functional status (IADL, EMS), psychosocial status (LSNS-6), and depression status (GDS-15). Binary logistic regression was used to assess the factors that were associated with depression. The median age of the elderly sample was 65.5 years. The prevalence of depression and food insecurity that was recorded were 13.2% and 19.5%, respectively. Social isolation (AOR = 5.882, 95% CI: 2.221, 15.576), food insecurity (AOR = 3.539, 95% CI: 1.350, 9.279), and unsafe mobility (AOR= 3.729, 95% CI: 1.302, 10.683) increased the odds of depression. In conclusion, social isolation, food insecurity, and unsafe mobility are factors associated with depression among the elderly people. Plans such as health interventions as well as grocery and financial aid among the qualifying elderly are suggested to improve this depression and food insecurity.
  16. Yousefi S, Bayat S, Rahman MB, Ibrahim Z, Abdulmalek E
    Chem Biodivers, 2017 Apr;14(4).
    PMID: 28036129 DOI: 10.1002/cbdv.201600362
    Inflammatory bowel disease (IBD) is the main risk factor for developing colorectal cancer which is common in patients of all ages. 5-Aminosalicylic acid (5-ASA), structurally related to the salicylates, is highly active in the treatment of IBD with minor side effects. In this study, the synthesis of galactose and fructose esters of 5-ASA was planned to evaluate the role of glycoconjugation on the bioactivity of the parent drug. The antibacterial activity of the new compounds were evaluated against two Gram-negative and two Gram-positive species of bacteria, with a notable effect observed against Staphylococcus aureus and Escherichia coli in comparisons with the 5-ASA. Cytotoxicity testing over HT-29 and 3T3 cell lines indicated that the toxicity of the new products against normal cells was significantly reduced compared with the original drug, whereas their activity against cancerous cells was slightly decreased. The anti-inflammatory activity test in RAW264.7 macrophage cells indicated that the inhibition of nitric oxide by both of the monosaccharide conjugated derivatives was slightly improved in comparison with the non-conjugated drug.
  17. Kasan NA, Ghazali NA, Ikhwanuddin M, Ibrahim Z
    Pak J Biol Sci, 2017;20(6):306-313.
    PMID: 29023055 DOI: 10.3923/pjbs.2017.306.313
    BACKGROUND AND OBJECTIVE: A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc.

    MATERIALS AND METHODS: For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC.

    RESULTS: Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp.

    CONCLUSION: In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

  18. Mohd Bahari Z, Ibrahim Z, Jaafar J, Shahir S
    Genome Announc, 2017 Oct 26;5(43).
    PMID: 29074663 DOI: 10.1128/genomeA.01183-17
    Microbacterium sp. strain SZ1 isolated from gold ores of a Malaysia gold mine was found to be highly resistant to arsenic. Here, we report the draft genome sequence of SZ1, which may provide further insights into understanding its arsenic resistance mechanism. In this draft genome, a complete set of ars operons and two additional scattered ars genes were encoded.
  19. Bahari Z, Ibrahim Z, Adznam SNA, Yusof BNM
    Asia Pac J Clin Nutr, 2017 8 15;26(5):781-787.
    PMID: 28802285 DOI: 10.6133/apjcn.102016.02
    BACKGROUND AND OBJECTIVES: Assessment of the nutrition care process (NCP) knowledge, attitudes, practices, and perceived barriers (KAPB) of dietetics practitioners is imperative before NCP is implemented completely in dietetics practice. No questionnaire assessing NCP KAPB has been developed and validated. Hence, we developed an NCP KAPB questionnaire called the KAPB-NCP and established its content validity.

    METHODS AND STUDY DESIGN: A total of 116 items associated with sociodemographic characteristics (7 items), professional development (3 items), organisational culture's support for the NCP (2 items), knowledge (27 items), attitudes (39 items), practices (20 items), and perceived barriers to implementing the NCP (14 items) were generated for potential inclusion in the KAPB-NCP questionnaire. The questionnaire was reviewed online by an expert panel for its content validity. An in-depth review was conducted by the research team for evaluating the overall comprehensiveness of the questionnaire.

    RESULTS: In total, 87 of 100 items of the KAPB sections showed an excellent content validity index (CVI; k* >0.74), whereas 10 showed a satisfactory CVI (k*=0.60-0.74). Only 3 items had a low CVI (k* <0.40). According to the expert panel revisions and the in-depth review, 72 items were incorporated into the questionnaire.

    CONCLUSIONS: The KAPB-NCP questionnaire is a content-valid instrument that can assess NCP KAPB.

  20. Riyahi N, Tohit ERM, Thambiah SC, Ibrahim Z
    Asia Pac J Clin Nutr, 2017 12 10;27(1):182-188.
    PMID: 29222897 DOI: 10.6133/apjcn.032017.01
    BACKGROUND AND OBJECTIVES: Recent studies have reported that obesity is associated with platelet activation and systemic inflammation. Malaysia has the highest prevalence of obesity, hence, this research is performed to evaluate the development of low-grade inflammation and platelet activation, measured using soluble CD40 ligand (sCD40L) and soluble P-selectin (sP-sel), and to determine their association with obesity. In addition, we assessed the mean platelet volume (MPV) and platelet count (PLT), which are novel parameters consistently associated with obesity.

    METHODS AND STUDY DESIGN: A cross-sectional study was conducted on 112 healthy men and women from 3 main ethnic group (Malay, Chinese, and Indian) who were aged 18-60 years. The participants were categorized into normal body mass index (BMI), overweight and obese groups according to WHO criteria for BMI in Asian populations (18.5 kg/m2

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