Displaying publications 41 - 60 of 180 in total

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  1. Zhang SS, Noordin MM, Rahman SO, Haron MJ
    Vet Hum Toxicol, 2001 Apr;43(2):83-7.
    PMID: 11308125
    An attempt was made to clarify the association between zinc (Zn) and antioxidants due to Zn supplementation on lipid peroxidation occurring during Brachiaria decumbens intoxication. The concentration of Zn, copper, malondialdehyde (MDA), superoxide dismutase (SOD), and gluthathione peroxidase (GSH-Px) were determined in tissues. There was a gradual increment in the concentration of Zn and MDA in serum and hepatocytic SOD in groups given Zn + B decumbens. A decline in erythrocytic GSH-Px and SOD, and lower concentration of reduced glutathione in hepatocyte cytosols were also detected in these sheep. It is highly suggestive that Zn supplementation may depress antioxidant status and enhance lipid peroxidation during B decumbens intoxication.
  2. Hashmi MB, Lemma TA, Ahsan S, Rahman S
    Entropy (Basel), 2021 Feb 22;23(2).
    PMID: 33671488 DOI: 10.3390/e23020250
    Generally, industrial gas turbines (IGT) face transient behavior during start-up, load change, shutdown and variations in ambient conditions. These transient conditions shift engine thermal equilibrium from one steady state to another steady state. In turn, various aero-thermal and mechanical stresses are developed that are adverse for engine's reliability, availability, and overall health. The transient behavior needs to be accurately predicted since it is highly related to low cycle fatigue and early failures, especially in the hot regions of the gas turbine. In the present paper, several critical aspects related to transient behavior and its modeling are reviewed and studied from the point of view of identifying potential research gaps within the context of fault detection and diagnostics (FDD) under dynamic conditions. Among the considered topics are, (i) general transient regimes and pertinent model formulation techniques, (ii) control mechanism for part-load operation, (iii) developing a database of variable geometry inlet guide vanes (VIGVs) and variable bleed valves (VBVs) schedules along with selection framework, and (iv) data compilation of shaft's polar moment of inertia for different types of engine's configurations. This comprehensive literature document, considering all the aspects of transient behavior and its associated modeling techniques will serve as an anchor point for the future researchers, gas turbine operators and design engineers for effective prognostics, FDD and predictive condition monitoring for variable geometry IGT.
  3. Lee JM, Yek SH, Wilson RF, Rahman S
    Acta Trop, 2020 Dec;212:105683.
    PMID: 32888935 DOI: 10.1016/j.actatropica.2020.105683
    Understanding the diversity and dynamics of the microbiota within the mosquito holobiome is of great importance to apprehend how the microbiota modulates various complex processes and interactions. This study examined the bacterial composition of Aedes albopictus across land use type and mosquito sex in the state of Selangor, Malaysia using 16S rRNA sequencing. The bacterial community structure in mosquitoes was found to be influenced by land use type and mosquito sex, with the environment and mosquito diet respectively identified to be the most likely sources of microbes. We found that approximately 70% of the microbiota samples were dominated by Wolbachia and removing Wolbachia from analyses revealed the relatively even composition of the remaining bacterial microbiota. Furthermore, microbial interaction network analysis highlighted the prevalence of co-exclusionary patterns in all networks regardless of land use and mosquito sex, with Wolbachia exhibiting co-exclusionary interactions with other residential bacteria such as Xanthomonas, Xenophilus and Zymobacter.
  4. Abdul Wahab MS, Abd Rahman S, Abu Samah R
    Heliyon, 2020 Nov;6(11):e05610.
    PMID: 33305039 DOI: 10.1016/j.heliyon.2020.e05610
    A two-level full factorial design was used to analyze several factors involved in PSF-GO-Pebax thin film nanocomposite membranes development. Permeate flux was chosen as a single response for four possible factors: Pebax selective layer concentration, amount of GO load to Pebax selective layer, Pebax-GO selective layer thickness, and amount of GO load to PSF substrate. The study is aimed at factors interaction and contribution towards the highest permeation flux via FFD and RSM approach. R2 obtained from the ANOVA is 0.9937 with Pebax concentration as the highest contributing factor. Pebax concentration-amount of GO load to PSF substrate is the only interaction contributing to the highest flux. A regression analysis concluded the study with model development and an optimized condition for the membrane design.
  5. Muniandy K, Tan MH, Song BK, Ayub Q, Rahman S
    Plant Mol Biol, 2019 May;100(1-2):33-46.
    PMID: 30788769 DOI: 10.1007/s11103-019-00841-x
    KEY MESSAGE: Grain amyloplast and leaf chloroplast DNA sequences are identical in rice plants but are differentially methylated. The leaf chloroplast DNA becomes more methylated as the rice plant ages. Rice is an important crop worldwide. Chloroplasts and amyloplasts are critical organelles but the amyloplast genome is poorly studied. We have characterised the sequence and methylation of grain amyloplast DNA and leaf chloroplast DNA in rice. We have also analysed the changes in methylation patterns in the chloroplast DNA as the rice plant ages. Total genomic DNA from grain, old leaf and young leaf tissues were extracted from the Oryza sativa ssp. indica cv. MR219 and sequenced using Illumina Miseq. Sequence variant analysis revealed that the amyloplast and chloroplast DNA of MR219 were identical to each other. However, comparison of CpG and CHG methylation between the identical amyloplast and chloroplast DNA sequences indicated that the chloroplast DNA from rice leaves collected at early ripening stage was more methylated than the amyloplast DNA from the grains of the same plant. The chloroplast DNA became more methylated as the plant ages so that chloroplast DNA from young leaves was less methylated overall than amyloplast DNA. These differential methylation patterns were primarily observed in organelle-encoded genes related to photosynthesis followed by those involved in transcription and translation.
  6. Islam S, Islam R, Mannan F, Rahman S, Islam T
    Prog Disaster Sci, 2020 Dec;8:100135.
    PMID: 34173450 DOI: 10.1016/j.pdisas.2020.100135
    Bangladesh is one of the worst hit countries in South Asia for COVID-19 outbreak. The objective of this article is to analyse healthcare, social and economic challenges faced by the country. Quantitative data and qualitative information from different sources have been used. Our analysis indicates that limited well-equipped hospitals, inadequate testing facilities, lack of awareness, improper knowledge, attitude to and practice of rules, poverty and precarious employment are the factors dominant in spreading COVID-19. Strict enforcement measures and ensuring people's adherence to rules may help reduce spread of infections. Adequate healthcare services are essential for establishing proper medical care.
  7. Ab Rahman S, Matic T, Yordanova M, Ariffin H
    Front Pediatr, 2021;9:758680.
    PMID: 35127585 DOI: 10.3389/fped.2021.758680
    Allogeneic haematopoietic stem cell transplantation (HSCT) is indicated in children with high-risk, relapsed or refractory acute lymphoblastic leukaemia (ALL). HLA-matched grafts from cord blood and stem cell repositories have allowed patients without suitable sibling donors to undergo HSCT. However, challenges in procuring matched unrelated donor (MUD) grafts due to high cost, ethnic disparity and time constraints have led to the exponential rise in the use of stem cells from human leukocyte antigen (HLA)-haploidentical family donors. Whilst HLA-haploidentical HSCT (hHSCT) performed in adult patients with acute leukaemia has produced outcomes similar to MUD transplants, experience in children is limited. Over the last 5 years, more data have emerged on hHSCT in the childhood ALL setting, allowing comparisons with matched donor transplants. The feasibility of hHSCT using adult family donors in childhood ALL may also address the ethical issues related to selection of minor siblings in matched sibling donor transplants. Here, we review hHSCT in paediatric recipients with ALL and highlight the emergence of hHSCT as a promising therapeutic option for patients lacking a suitable matched donor. Recent issues related to conditioning regimens, donor selection and graft-vs.-host disease prophylaxis are discussed. We also identify areas for future research to address transplant-related complications and improve post-transplant disease-free survival.
  8. Khanis NH, Ritikos R, Ahmad Kamal SA, Abdul Rahman S
    Materials (Basel), 2017 Jan 24;10(2).
    PMID: 28772460 DOI: 10.3390/ma10020102
    Nanostructured hydrogenated carbon nitride (CNx:H) thin films were synthesized on a crystal silicon substrate at low deposition temperature by radio-frequency plasma-enhanced chemical vapor deposition (PECVD). Methane and nitrogen were the precursor gases used in this deposition process. The effects of N₂ to the total gas flow rate ratio on the formation of CNx:H nanostructures were investigated. Field-emission scanning electron microscopy (FESEM), Auger electron spectroscopy (AES), Raman scattering, and Fourier transform of infrared spectroscopies (FTIR) were used to characterize the films. The atomic nitrogen to carbon ratio and sp² bonds in the film structure showed a strong influence on its growth rate, and its overall structure is strongly influenced by even small changes in the N₂:(N₂ + CH₄) ratio. The formation of fibrous CNx:H nanorod structures occurs at ratios of 0.7 and 0.75, which also shows improved surface hydrophobic characteristic. Analysis showed that significant presence of isonitrile bonds in a more ordered film structure were important criteria contributing to the formation of vertically-aligned nanorods. The hydrophobicity of the CNx:H surface improved with the enhancement in the vertical alignment and uniformity in the distribution of the fibrous nanorod structures.
  9. Husin NA, Rahman S, Karunakaran R, Bhore SJ
    Genet Mol Biol, 2023;45(4):e20210379.
    PMID: 36622241 DOI: 10.1590/1678-4685-GMB-2021-0379
    Durian (Durio zibethinus Murr.) fruits are famous for their unique aroma. This study analysed the Durian fruit transcriptome to discover the expression patterns of genes and to understand their regulation. Three developmental stages of Durian fruit, namely, early [90 days post-anthesis (DPA)], mature (120 DPA), and ripen (127 DPA), were studied. The Illumina HiSeq platform was used for sequencing. The sequence data were analysed using four different mapping aligners and statistical methods: CLC Genomic Workbench, HISAT2+DESeq2, Tophat+Cufflinks, and HISAT2+edgeR. The analyses showed that over 110 million clean reads were mapped to the Durian genome, yielding 19,976, 11,394, 17,833, and 24,351 differentially expressed genes during 90-127 days post-anthesis. Many identified differentially expressed genes were linked to the fruit ripening processes. The data analysis suggests that most genes with increased expression at the ripening stage were primarily involved in the metabolism of cofactors and vitamins, nucleotide metabolism, and carbohydrate metabolism. Significantly expressed genes from the young to mature stage were mainly associated with carbohydrate metabolism, amino acid metabolism, and cofactor and vitamin metabolism. The transcriptome data will serve as a foundation for understanding Durian fruit development-specific genes and could be helpful in fruit's trait improvement.
  10. Oh L, Ab Rahman S, Dubinsky K, Azanan MS, Ariffin H
    Technol Cancer Res Treat, 2023;22:15330338221149799.
    PMID: 36624625 DOI: 10.1177/15330338221149799
    Recent studies have identified causal links between altered gut microbiome, chronic inflammation, and inflammation-driven conditions such as diabetes and cardiovascular disease. Childhood cancer survivors (CCS) show late effects of therapy in the form of inflammaging-related disorders as well as microbial dysbiosis, supporting a hypothesis that the conditions are interconnected. Given the susceptibility of the gut microbiome to alteration, a number of therapeutic interventions have been investigated for the treatment of inflammatory conditions, though not within the context of cancer survivorship in children and adolescents. Here, we evaluate the potential for these interventions, which include probiotic supplementation, prebiotics/fiber-rich diet, exercise, and fecal microbiota transplantation for prevention and treatment of cancer treatment-related microbial dysbiosis in survivors. We also make recommendations to improve adherence and encourage long-term lifestyle changes for maintenance of healthy gut microbiome in CCS as a potential strategy to mitigate treatment-related late effects.
  11. Kalidasan B, Pandey AK, Aljafari B, Chinnasamy S, Kareri T, Rahman S
    J Environ Manage, 2023 Dec 15;348:119439.
    PMID: 37890400 DOI: 10.1016/j.jenvman.2023.119439
    Metal, carbon and conducting polymer nanoparticles are blended with organic phase change materials (PCMs) to enhance the thermal conductivity, heat storage ability, thermal stability and optical property. However, the existing nanoparticle are expensive and need to be handle with high caution during operation as well during disposal owing to its toxicity. Subsequently handling of solid waste and the disposal of organic PCM after longevity usage are of utmost concern and are less exposed. Henceforth, the current research presents a new dimension of exploration by green synthesized nanoparticles from a thorny shrub of an invasive weed named Prosopis Juliflora (PJ) which is a agro based solid waste. Subsequently, the research is indented to decide the concentration of green synthesized nanoparticle for effective heat transfer rate of organic PCM (Tm = 35-40 °C & Hm = 145 J/g). Furthermore, an in-depth understanding on the kinetic and thermodynamic profile of degradation mechanism involved in disposal of PCM after usage via Coats and Redfern technique is exhibited. Engaging a two-step method, we fuse the green synthesized nanomaterial with PCM to obtain nanocomposite PCM. On experimental evaluation, thermal conductivity of the developed nanocomposite (PCM + PJ) increases by 63.8% (0.282 W/m⋅K to 0.462 W/m⋅K) with 0.8 wt% green synthesized nanomaterial owing to the uniform distribution of nanoparticle within PCM matrix thereby contributing to bridging thermal networks. Subsequently, PCM and PCM + PJ nanocomposites are tested using thermogravimetric analyzer at different heating rates (05 °C/min; 10 °C/min; 15 °C/min & 20 °C/min) to analyze the decomposition kinetic reaction. The kinetic and thermodynamic profile of degradation mechanism involved in disposal of PCM and its nanocomposite of PCM + PJ provides insight on thermal parameters to be considered on large scale operation and to understand the complex nature of the chemical reactions. Adopting thirteen different chemical mechanism model under Coats and Redfern method we determine the reaction mechanism; kinetic parameter like activation energy (Ea) & pre-exponential factor (A) and thermodynamic parameter like change in enthalpy (ΔH), change in Gibbs free energy (ΔG) and change in entropy (ΔS). Dispersion of PJ nanomaterial with PCM reduces Ea from 370.82 kJ/mol-1 to 342.54 kJ/mol-1 (7.7% reduction), as the developed nanomaterial is enriched in carbon element and exhibits a catalytic effect for breakdown reaction. Corresponding, value of ΔG for PCM and PCM + PJ sample within heating rates of 05-20 °C/min varies between 168.95 and 41.611 kJ/mol-1. The current research will unbolt new works with focus on exploring the pyrolysis behaviour of phase change materials and its nanocomposite used for energy storage applications. This work also provides insights on the disposal of PCM which is an organic solid waste. The thermo-kinetic profile will help to investigate and predict the optimum heating rate and temperature range for conversion of micro-scale pyrolysis to commercial scale process.
  12. Ten KE, Muzahid NH, Rahman S, Tan HS
    PLoS One, 2023;18(4):e0283960.
    PMID: 37018343 DOI: 10.1371/journal.pone.0283960
    Galleria mellonella larvae have been increasingly used in research, including microbial infection studies. They act as suitable preliminary infection models to study host-pathogen interactions due to their advantages, such as the ability to survive at 37°C mimicking human body temperature, their immune system shares similarities with mammalian immune systems, and their short life cycle allowing large-scale studies. Here, we present a protocol for simple rearing and maintenance of G. mellonella without requiring special instruments and specialized training. This allows the continuous supply of healthy G. mellonella for research purposes. Besides, this protocol also provides detailed procedures on the (i) G. mellonella infection assays (killing assay and bacterial burden assay) for virulence studies and (ii) bacterial cell harvesting from infected larvae and RNA extraction for bacterial gene expression studies during infection. Our protocol could not only be used in the studies of A. baumannii virulence but can also be modified according to different bacterial strains.
  13. Tan ML, Rahman S, Robinson F, Sani MHM
    Pharm Pract (Granada), 2023;21(1):2779.
    PMID: 37090453 DOI: 10.18549/PharmPract.2023.1.2779
    INTRODUCTION: Self-Medication, which is a practice to self-treat using medicine without consulting a medical practitioner or a doctor, is a common practice and the Pandemic Covid-19 may have caused people to resort to self-medication in order to reduce the infectivity of the Covid-19.

    OBJECTIVE: To validate and develop an instrument in Bahasa Melayu to assess the psychological distress and self-medication during pandemic Covid-19 in WP Labuan.

    METHODS: A pilot study was conducted among 160 participants in WP Labuan. Reliability testing on internal consistency and content validity was performed on the adapted Covid-19 Peritraumatic Distress Index (CPDI) as well as domain on knowledge, practice and attitude of self-medication.

    RESULT: A panel of seven experts evaluated the research instrument for content validity and it was found to have good content item validity. The CPDI domain showed good internal consistency of Cronbach's Alpha of 0.919. The mean (SD) CPDI score of the respondents in WP Labuan was 32.55 (15.98). 64.2% of the respondents experienced psychological distress. The variable for Area (town/countryside) was found to be statistically significant (p<0.05) to be associated with self-medication during the pandemic.

    CONCLUSION: The instrument established sound reliability and validity and therefore, can be an effective tool for assessing psychological distress and self-medication in the Malaysian population.

  14. Tan MS, White AP, Rahman S, Dykes GA
    PLoS One, 2016;11(6):e0158311.
    PMID: 27355584 DOI: 10.1371/journal.pone.0158311
    Cases of foodborne disease caused by Salmonella are frequently associated with the consumption of minimally processed produce. Bacterial cell surface components are known to be important for the attachment of bacterial pathogens to fresh produce. The role of these extracellular structures in Salmonella attachment to plant cell walls has not been investigated in detail. We investigated the role of flagella, fimbriae and cellulose on the attachment of Salmonella Typhimurium ATCC 14028 and a range of isogenic deletion mutants (ΔfliC fljB, ΔbcsA, ΔcsgA, ΔcsgA bcsA and ΔcsgD) to bacterial cellulose (BC)-based plant cell wall models [BC-Pectin (BCP), BC-Xyloglucan (BCX) and BC-Pectin-Xyloglucan (BCPX)] after growth at different temperatures (28°C and 37°C). We found that all three cell surface components were produced at 28°C but only the flagella was produced at 37°C. Flagella appeared to be most important for attachment (reduction of up to 1.5 log CFU/cm2) although both cellulose and fimbriae also aided in attachment. The csgD deletion mutant, which lacks both cellulose and fimbriae, showed significantly higher attachment as compared to wild type cells at 37°C. This may be due to the increased expression of flagella-related genes which are also indirectly regulated by the csgD gene. Our study suggests that bacterial attachment to plant cell walls is a complex process involving many factors. Although flagella, cellulose and fimbriae all aid in attachment, these structures are not the only mechanism as no strain was completely defective in its attachment.
  15. Daniel DS, Lee SM, Dykes GA, Rahman S
    Appl Environ Microbiol, 2015 Sep;81(18):6090-7.
    PMID: 26150452 DOI: 10.1128/AEM.01741-15
    Enterococci rank as one of the leading causes of nosocomial infections, such as urinary tract infections, surgical wound infections, and endocarditis, in humans. These infections can be hard to treat because of the rising incidence of antibiotic resistance. Enterococci inhabiting nonhuman reservoirs appear to play a critical role in the acquisition and dissemination of antibiotic resistance determinants. The spread of antibiotic resistance has become a major concern in both human and veterinary medicine, especially in Southeast Asia, where many developing countries have poor legislation and regulations to control the supply and excessive use of antimicrobials. This review addresses the occurrence of antibiotic-resistant enterococci in Association of Southeast Asian Nations countries and proposes infection control measures that should be applied to limit the spread of multiple-drug-resistant enterococci.
  16. Husin NA, Rahman S, Karunakaran R, Bhore SJ
    Bioinformation, 2018;14(6):265-270.
    PMID: 30237671 DOI: 10.6026/97320630014265
    Durian (Durio zibethinus L.; Family Bombacaceae) is an iconic tropical fruit plant cultivated in Malaysia and the Southeast Asian countries. In Malaysia, durian is recognised as the King of fruits and well known as a rich source of volatile sulphur compounds that make it unique. Fruit pulp of this fruit is an excellent source of nutrients as it contains proteins, dietary fat, fibers, and carbohydrates. Durian leaf and root decoctions are known to have a febrifuge and anti-malarial properties. The understanding of this plant's molecular biology will help breeders to develop a strategy for its further improvements. Hence, there is a need to identify and understand the genes necessary for the quality improvement of the durian fruits. Its genome contains about 46,000 genes which is almost double that of humans (Homo sapiens). The understanding of durian genes will be useful not only in the molecular breeding but also in the microbial production of novel proteins and or enzymes. This review highlights nutritional and medicinal attributes of durian. The molecular studies including the importance of undertaking transcriptomics work and the insights from the most recently reported genome draft are also highlighted.
  17. Tiwari GJ, Liu Q, Shreshtha P, Li Z, Rahman S
    BMC Plant Biol, 2016 08 31;16(1):189.
    PMID: 27581494 DOI: 10.1186/s12870-016-0881-6
    BACKGROUND: The bran from polished rice grains can be used to produce rice bran oil (RBO). High oleic (HO) RBO has been generated previously through RNAi down-regulation of OsFAD2-1. HO-RBO has higher oxidative stability and could be directly used in the food industry without hydrogenation, and is hence free of trans fatty acids. However, relative to a classic oilseed, lipid metabolism in the rice grain is poorly studied and the genetic alteration in the novel HO genotype remains unexplored.

    RESULTS: Here, we have undertaken further analysis of role of OsFAD2-1 in the developing rice grain. The use of Illumina-based NGS transcriptomics analysis of developing rice grain reveals that knockdown of Os-FAD2-1 gene expression was accompanied by the down regulation of the expression of a number of key genes in the lipid biosynthesis pathway in the HO rice line. A slightly higher level of oil accumulation was also observed in the HO-RBO.

    CONCLUSION: Prominent among the down regulated genes were those that coded for FatA, LACS, SAD2, SAD5, caleosin and steroleosin. It may be possible to further increase the oleic acid content in rice oil by altering the expression of the lipid biosynthetic genes that are affected in the HO line.

  18. Islam MN, Majumder MA, Ja'afar R, Rahman S
    Malays J Med Sci, 2005 Jan;12(1):26-8.
    PMID: 22605944
    Lecture handouts are widely used instructional tools. Handouts supplement rather than substitute students' regular reading. It is now a common practice to supply PowerPoint handouts and publish lecture handouts on the web for students' access. A study was conducted among the first year medical students (n=142) of School of Medical Sciences (SMS), Universiti Sains Malaysia (USM) in order to determine their perceptions and expectations with regards to lecture handouts provided to them. The majority of the students reported that they read the lecture handouts as a reference and found them useful as a guide for future learning. More than half (68%) of the students expressed dissatisfaction with the overall presentation format of the handouts which is mainly technology-related i.e. PowerPoint and photocopying. This study indicated that students' expectations and experiences were positive towards the use of handouts. They used handouts as a means of supplementing rather than substituting their learning. Much care is needed when educators supply computer-based handouts, as this study shows a number of limitations when students use them. Medical schools should consider publishing web-based handouts with online and other facilities to make it interesting and effective.
  19. Ahmad MS, Abuzar MA, Razak IA, Rahman SA, Borromeo GL
    Eur J Dent Educ, 2017 Nov;21(4):e29-e38.
    PMID: 27273317 DOI: 10.1111/eje.12211
    Poor oral health has been associated with compromised general health and quality of life. To promote comprehensive patient management, the role of medical professionals in oral health maintenance is compelling, thus indicating the need for educational preparation in this area of practice. This study aimed to determine the extent of training in oral health in Malaysian and Australian medical schools. An audio-recorded semi-structured phone interview involving Academic Programme Directors in Malaysian (n = 9, response rate=81.8%) and Australian (n = 7, response rate = 35.0%) medical schools was conducted during the 2014/2015 and 2014 academic years, respectively. Qualitative data was analysed via thematic analysis, involving coding and grouping into emerging themes. Quantitative data were measured for frequencies. It was found that medical schools in Malaysia and Australia offered limited teaching of various oral health-related components that were mostly integrated throughout the curriculum, in the absence of structured learning objectives, teaching methodologies and assessment approaches. Barriers to providing oral health education included having insufficient expertise and overloaded curriculum. As medical educators demonstrated support for oral health education, collaboration amongst various stakeholders is integral to developing a well-structured curriculum and practice guidelines on oral health management involving medical professionals.
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