Displaying publications 41 - 60 of 434 in total

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  1. Mohd Saidi N, Abdullah N, Norizan MN, Janudin N, Mohd Kasim NA, Osman MJ, et al.
    Nanomaterials (Basel), 2022 Nov 07;12(21).
    PMID: 36364698 DOI: 10.3390/nano12213922
    The reputation of nanofluids as a convenient heat transfer media has grown in recent years. The synthesis of nanofluids is often challenging, particularly carbon-based nanofluids, due to the rapid agglomeration of the nanoparticles and the instability of the nanofluids. In this regard, surface modification and surfactant addition are potential approaches to improve the physical and thermal properties of carbon-based nanofluids that have been studied and the structural, morphological, and thermal characteristics of surface-oxidised carbon nanofibre (CNF)-based nanofluids has been characterised. Commercial CNF was first subjected to three different acid treatments to introduce surface oxygen functional groups on the CNF surface. Following the physical and thermal characterisation of the three surface-oxidised CNFs (CNF-MA, CNF-MB, and CNF-MC), including Raman spectroscopy, Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM), the CNF-MB was selected as the best method to synthesise the surface-oxidised CNF-based nanofluid. A total of 40 mL of ultrapure water was used as a pure base fluid and mixed with the surface-oxidised CNF at a concentration range of 0.1-1.0 wt.%, with a fixed of 10 wt.% amount of polyvinylpyrrolidone (PVP). The thermal conductivity of CNF-based nanofluid was then characterised at different temperatures (6, 25, and 40 °C). Based on the results, surface oxidation via Method B significantly affected the extent of surface defects and effectively enhanced the group functionality on the CNF surface. Aside from the partially defective and rough surface of CNF-MB surfaces from the FESEM analysis, the presence of surface oxygen functional groups on the CNF wall was confirmed via the Raman analysis, TGA curve, and FTIR analysis. The visual sedimentation observation also showed that the surface-oxidised CNF particles remained dispersed in the nanofluid due to the weakened van der Waals interaction. The dispersion of CNF particles was improved by the presence of PVP, which further stabilised the CNF-based nanofluids. Ultimately, the thermal conductivity of the surface-oxidised CNF-based nanofluid with PVP was significantly improved with the highest enhancement percentage of 18.50, 16.84, and 19.83% at 6, 25, and 40 °C, respectively, at an optimum CNF concentration of 0.7 wt.%.
  2. Raouf AA, Samudin AR, Samian R, Akool K, Abdullah N
    Med J Malaysia, 2004 May;59 Suppl B:49-50.
    PMID: 15468813
    This study was designed to investigate the surface properties especially surface porosity of polyhydroxybutyrate (PHB) using scanning electron microscopy. PHB granules were sprinkled on the double-sided sticky tape attached on a SEM aluminium stub and sputtered with gold(10nm thickness) in a Polaron SC515 Coater, following which the samples were placed into the SEM specimen chamber for viewing and recording. Scanning electron micrographs with different magnification of PHB surface revealed multiple pores with different sizes.
  3. Buji RI, Abdul Murad NA, Chan LF, Maniam T, Mohd Shahrir MS, Rozita M, et al.
    Lupus, 2018 Apr;27(5):744-752.
    PMID: 29161964 DOI: 10.1177/0961203317742711
    Background Systemic lupus erythematosus (SLE) patients are a high-risk population for suicide. Glutamatergic neurosystem genes have been implicated in the neurobiology of depression in SLE and suicidal behaviour in general. However, the role of glutamate receptor gene polymorphisms in suicidal behaviour among SLE patients remains unclear in the context of established clinical and psychosocial factors. We aimed to investigate the association of NR2A gene polymorphism with suicidal ideation in SLE while accounting for the interaction between clinical and psychosocial factors. Methods A total of 130 SLE patients were assessed for mood disorders (MINI International Neuropsychiatric Interview), severity of depression (Patient Health Questionnaire-9), suicidal behaviour (Columbia-Suicide Severity Rating Scale), socio-occupational functioning (Work and Social Adjustment Scale), recent life events (Social Readjustment Rating Scale) and lupus disease activity (SELENA-SLE Disease Activity Index). Eighty-six out of the 130 study participants consented for NR2A genotyping. Results Multivariable logistic regression showed nominal significance for the interaction effect between the NR2A rs2072450 AC genotype and higher severity of socio-occupational impairment with lifetime suicidal ideation in SLE patients ( p = 0.038, odds ratio = 1.364, 95% confidence interval = 1.018-1.827). However, only the association between lifetime mood disorder and lifetime suicidal ideation remained significant after Bonferroni correction ( p 
  4. Salam A, Mahadevan R, Abdul Rahman A, Abdullah N, Abd Harith AA, Shan CP
    Pak J Med Sci, 2015 Jan-Feb;31(1):169-73.
    PMID: 25878637 DOI: 10.12669/pjms.311.6473
    OBJECTIVE: To identify the stress-prevalence and coping-strategies among University Kebangsaan Malaysia (UKM) medical students.
    METHODS: This was an observational study conducted among 234 UKM first and third year medical students. Standardized questionnaire on stress and coping strategies was used. Stress data was related to subjective experiences on some positive and negative adjectives such as tense, relaxed etc. Positive adjectives were measured by sign "++" and "+" scoring "1" while stress-negative adjectives were measured by sign "?" and "-" scoring "0". Forty-eight coping items under task, emotion and avoidance strategies were measured using 5-point Likert-scale.
    RESULTS: Overall stress-prevalence was 49%. Female and Malay respondents were more stressed. Significant differences of stress-level was observed between Malays and non Malays in first year (p=0.04) and in third year (p=0.01). Most common strategies used to cope stress was task-oriented while emotion oriented was least.
    CONCLUSION: Stress-prevalence and stress-level in UKM medical students was high. Most of the respondents coped stress using task-oriented strategies. Stressor and its effective management must be ensured. Educational institutions should act as a creative designer of learning environment to get relieve from educational stressor.
    KEYWORDS: Coping strategies; Medical students; Stress prevalence
  5. Tumin M, Noh A, Chong CS, Mohd Satar N, Lim SK, Abdullah N, et al.
    Ann. Transplant., 2013;18:314-9.
    PMID: 23792535 DOI: 10.12659/AOT.883957
    This paper aimed to assess the willingness of Malaysians with post-secondary education to be living kidney donors.
  6. Ismail NA, Abu Bakar SN, Abdullah N, Shafie MS, Mohd Nor F
    Malays J Pathol, 2019 Aug;41(2):83-89.
    PMID: 31427544
    INTRODUCTION: Stature estimation is population dependent, and population-specific regression equations should be generated for accurate anthropological assessments. Nevertheless, stature estimation data was inaccessible and limited in some of the South-East Asian countries. The systematic review was conducted to analyse the regression equations of stature estimations developed in South-East Asian region.

    MATERIALS AND METHODS: A systematic literature search was performed through SCOPUS database and Google Scholar from January till March 2018. All published articles which developed stature estimation from different types of bone, methods and type of statures (i.e. living stature, forensic stature and cadaveric stature) were included in this study. Risks of biases were also assessed. Population studies with no regression equations were excluded from the study.

    RESULTS: Seven studies that met the inclusion criteria were identified. In the South-East Asia region, regression equations for stature estimation were developed in Thailand and Malaysia. In these studies, bone measurements were done either by radiography, direct bone measurement, or palpation on body surface for anatomical bony prominence. All of these studies used various parts of bones for stature estimation.

    CONCLUSION: The most widely used regression equations for stature estimation in South-East Asian population were from the Thailand population. Further research is recommended to develop regression equations for other South-East Asian countries.

  7. Abdullah N, Goh YX, Othman R, Ismail N, Jalal N, Wan Sallam WAF, et al.
    J Clin Lab Anal, 2023 Apr;37(8):e24898.
    PMID: 37243371 DOI: 10.1002/jcla.24898
    OBJECTIVE: Glycated haemoglobin (HbA1c) is a standard indication for screening type 2 diabetes that also has been widely used in large-scale epidemiological studies. However, its long-term quality (in terms of reproducibility) stored in liquid nitrogen is still unknown. This study is aimed to evaluate the stability and reproducibility of HbA1c measurements from frozen whole blood samples kept at -196°C for more than 7 years.

    METHODS: A total of 401 whole blood samples with a fresh HbA1c measurement were randomly selected from The Malaysian Cohort's (TMC) biobank. The HbA1c measurements of fresh and frozen (stored for 7-8 years) samples were assayed using different high-performance liquid chromatography (HPLC) systems. The HbA1c values of the fresh samples were then calculated and corrected according to the later system. The reproducibility of HbA1c measurements between calculated-fresh and frozen samples was assessed using a Passing-Bablok linear regression model. The Bland-Altman plot was then used to evaluate the concordance of HbA1c values.

    RESULTS: The different HPLC systems highly correlated (r = 0.99) and agreed (ICC = 0.96) with each other. Furthermore, the HbA1c measurements for frozen samples strongly correlate with the corrected HbA1c values of the fresh samples (r = 0.875) with a mean difference of -0.02 (SD: -0.38 to 0.38). Although the mean difference is small, discrepancies were observed within the diabetic and non-diabetic samples.

    CONCLUSION: These data demonstrate that the HbA1c measurements between fresh and frozen samples are highly correlated and reproducible.

  8. Shahrokh Abadi MH, Hamidon MN, Shaari AH, Abdullah N, Wagiran R
    Sensors (Basel), 2011;11(8):7724-35.
    PMID: 22164041 DOI: 10.3390/s110807724
    A gas sensor array was developed in a 10 × 10 mm(2) space using Screen Printing and Pulse Laser Ablation Deposition (PLAD) techniques. Heater, electrode, and an insulator interlayer were printed using the screen printing method on an alumina substrate, while tin oxide and platinum films, as sensing and catalyst layers, were deposited on the electrode at room temperature using the PLAD method, respectively. To ablate SnO(2) and Pt targets, depositions were achieved by using a 1,064 nm Nd-YAG laser, with a power of 0.7 J/s, at different deposition times of 2, 5 and 10 min, in an atmosphere containing 0.04 mbar (4 kPa) of O(2). A range of spectroscopic diffraction and real space imaging techniques, SEM, EDX, XRD, and AFM were used in order to characterize the surface morphology, structure, and composition of the films. Measurement on the array shows sensitivity to some solvent and wood smoke can be achieved with short response and recovery times.
  9. Gendeh BS, Murad S, Razi AM, Abdullah N, Mohamed AS, Kadir KA
    Otolaryngol Head Neck Surg, 2000 May;122(5):758-62.
    PMID: 10793361
    The aim of the study was to determine the incidence of food and house dust mite (HDM) allergy in patients with nasal congestion and rhinorrhea attending the Otorhinolaryngology Clinic, National University of Malaysia, Kuala Lumpur. This was a prospective matched, controlled study of patients skin prick tested with commercial food and common aeroallergens. The participants were 148 Malaysian adults with symptoms of nasal congestion and rhinorrhea and 113 adult Malaysian control subjects without rhinitis symptoms. The skin prick test (SPT) was used to evaluate 11 foods common to the Malaysian diet and 3 HDM inhalants. Forty-eight percent of the patients with rhinitis had positive SPT results to foods, compared with 4.4% of control subjects (P < 0.05). The most commonly implicated foods were shrimp (48%) and rice (30%), which are common in the Malaysian diet. Seventy-two percent of rhinitis patients had positive SPT results to HDM, compared with 22.2% of control subjects (P < 0.05). Patients with rhinitis also had significantly more gastrointestinal problems than control subjects (P < 0.05). The incidences of HDM and food allergy are significantly greater in Malaysian adults with rhinitis symptoms than in control subjects without rhinitis. The effect of avoidance or immunotherapy awaits further study.
    Study site: Otorhinolaryngology Clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
  10. Ezat SW, Syed Junid SM, Noraziani K, Zafar A, Saperi S, Nur AM, et al.
    Asian Pac J Cancer Prev, 2013;14(5):3357-62.
    PMID: 23803129
    The human skeleton is the most common organ to be affected by metastatic cancer and bone metastases are a major cause of cancer morbidity. The five most frequent cancers in Malaysia among males includes prostate whereas breast cancer is among those in females, both being associated with skeletal lesions. Bone metastases weaken bone structure, causing a range of symptoms and complications thus developing skeletal-related events (SRE). Patients with SRE may require palliative radiotherapy or surgery to bone for pain, having hypercalcaemia, pathologic fractures, and spinal cord compression. These complications contribute to a decline in patient health- related quality of life. The multidimensional assessment of health-related quality of life for those patients is important other than considering a beneficial treatment impact on patient survival, since the side effects of treatment and disease symptoms can significantly impact health-related quality of life. Cancer treatment could contribute to significant financial implications for the healthcare system. Therefore, it is essential to assess the health-related quality of life and treatment cost, among prostate and breast cancer patients in countries like Malaysia to rationalized cost-effective way for budget allocation or utilization of health care resources, hence helping in providing more personalized treatment for cancer patients.
  11. Hanifah AH, Teng ST, Law IK, Abdullah N, Chiba SUA, Lum WM, et al.
    Harmful Algae, 2022 Dec;120:102338.
    PMID: 36470602 DOI: 10.1016/j.hal.2022.102338
    Thirty-four strains of Heterocapsa were established from Malaysian waters and their morphologies were examined by light, scanning, and transmission electron microscopy. Three species, H. bohaiensis, H. huensis, and H. rotundata, and three new species, H. borneoensis sp. nov., H. limii sp. nov., and H. iwatakii sp. nov. were described in this study. The three species were differentiated morphologically by unique characteristics of cell size, shape, displacement of the cingulum, shape and position of nucleus, the number and position of pyrenoids, and body scale ultrastructure. The species delimitations were robustly supported by the molecular data. A light-microscopy-based key to species of Heterocapsa is established, with two major groups, i.e., species with a single pyrenoid, and species with multiple pyrenoids. Bioassays were conducted by exposing Artemia nauplii to Heterocapsa densities of 1-5 × 105 cells mL-1, and treatments exposed to H. borneoensis showed naupliar mortality, while no naupliar death was observed in the treatments exposed to cells of H. bohaiensis, H. huensis, H. limii, and H. iwatakii. Naupliar death was observed during the initial 24 h for both tested H. borneoensis strains, and mortality rates increased up to 50% after 72-h exposure. This study documented for the first time the diversity and cytotoxic potency of Heterocapsa species from Malaysian waters.
  12. Abdullah N, Chin NL
    Bioresour Technol, 2010 Nov;101(21):8205-10.
    PMID: 20624604 DOI: 10.1016/j.biortech.2010.05.068
    Composting is a good recycling method to fully utilise all the organic wastes present in kitchen waste due to its high nutritious matter within the waste. In this present study, the optimised mixture proportions of kitchen waste containing vegetable scraps (V), fish processing waste (F) and newspaper (N) or onion peels (O) were determined by applying the simplex-centroid mixture design method to achieve the desired initial moisture content and carbon-to-nitrogen (CN) ratio for effective composting process. The best mixture was at 48.5% V, 17.7% F and 33.7% N for blends with newspaper while for blends with onion peels, the mixture proportion was 44.0% V, 19.7% F and 36.2% O. The predicted responses from these mixture proportions fall in the acceptable limits of moisture content of 50% to 65% and CN ratio of 20-40 and were also validated experimentally.
  13. Abdullah N, Baharudin N, Mohd Rustam FR, Khalid Z
    Clin Pract, 2021 Oct 26;11(4):785-790.
    PMID: 34842643 DOI: 10.3390/clinpract11040094
    Eosinophilic leukocytosis can be attributed to a number of clinical conditions such as parasitic infection, allergies, and neoplasms. Parasitic infection is the main cause of eosinophilia; however, a marked leukocytosis with hypereosinophilia secondary to Trichuris trichiura in adults has not been previously reported. We describe a case of a 39-year-old man who presented with fever and diarrhea. The investigation revealed a white blood cell (WBC) count of 20.69 × 109/L with an absolute eosinophil count of 12.44 × 109/L. Fecal microscopic examination demonstrated T. trichuria eggs. The WBC count returned to normal following treatment with albendazole. The literature pertaining to hematological findings associated with Trichuris trichiura is explored in this report. This case highlights that a significant elevation of leukocyte count with hypereosinophilia can be one of the manifestations of trichuriasis infection in adults. Empirical treatment with anti-helminthic agents may play a role in suspected cases to avoid severe complications, such as Trichuris dysentery syndrome.
  14. Abdullah NR, Furuta T, Taib R, Kita K, Kojima S, Wah MJ
    Am J Trop Med Hyg, 1996 Feb;54(2):162-3.
    PMID: 8619441
    We describe here a reverse transcriptase-polymerase chain reaction method for the detection of malaria parasites. Ten in vitro-cultured isolates of Plasmodium falciparum and 16 specimens from patients infected with P. falciparum were used to examine the specificity and sensitivity of the test. The sensitivity of the test was 0.3 parasites per microliter of blood. Specificity was determined by matching the sequences of the specimens' DNA to published sequences of 18S ribosomal RNA genes in the species-specific region. The test proved to be very sensitive and specific for the detection of P. falciparum infection.
  15. Muhamad NA, Ab Ghani RM, Abdul Mutalip MH, Muhammad EN, Mohamad Haris H, Mohd Zain R, et al.
    Sci Rep, 2020 12 03;10(1):21009.
    PMID: 33273475 DOI: 10.1038/s41598-020-77813-5
    Malaysia is a country with an intermediate endemicity for hepatitis B. As the country moves toward hepatitis B and C elimination, population-based estimates are necessary to understand the burden of hepatitis B and C for evidence-based policy-making. Hence, this study aims to estimate the prevalence of hepatitis B and C in Malaysia. A total of 1458 participants were randomly selected from The Malaysian Cohort (TMC) aged 35 to 70 years between 2006 and 2012. All blood samples were tested for hepatitis B and C markers including hepatitis B surface antigen (HBsAg), anti-hepatitis B core antibody (anti-HBc), antibodies against hepatitis C virus (anti-HCV). Those reactive for hepatitis C were further tested for HCV RNA genotyping. The sociodemographic characteristics and comorbidities were used to evaluate their associated risk factors. Descriptive analysis and multivariable analysis were done using Stata 14. From the samples tested, 4% were positive for HBsAg (95% CI 2.7-4.7), 20% were positive for anti-HBc (95% CI 17.6-21.9) and 0.3% were positive for anti-HCV (95% CI 0.1-0.7). Two of the five participants who were reactive for anti-HCV had the HCV genotype 1a and 3a. The seroprevalence of HBV and HCV infection in Malaysia is low and intermediate, respectively. This population-based study could facilitate the planning and evaluation of the hepatitis B and C control program in Malaysia.
    Study name: The Malaysian Cohort (TMC) project
  16. Mohd Roffeei SH, Abdullah N, Basar SK
    Int J Med Inform, 2015 May;84(5):375-85.
    PMID: 25701266 DOI: 10.1016/j.ijmedinf.2015.01.015
    PURPOSE: This study examined the types of social support messages exchanged between parents and/or caregivers of children with Autism Spectrum Disorders (ASDs) who communicate via Facebook (FB); it studies two autism support groups: Autism Malaysia (AM) and Autism Children Club (ACA).
    METHOD: A total of 3637 messages including both postings (381) and comments (3256) were gathered from August to November 2013. The study employed a deductive content-analysis approach. The qualitative data were analyzed for social support themes adapted from the Social Support Behavior Code (SSBC). Before collecting the data, email was sent to the FB groups' moderators to gain formal consent from the members.
    RESULT: The finding indicated that the highest percentage of messages offered dealt with Informational support (30.7%) followed by Emotional support (27.8%). Network and Esteem support messages were responsible for 20.97% and 20.2%, respectively. Tangible Assistance was the least frequent category (0.4%). A majority of these messages discussed and addressed challenges and difficulties associated with caring and raising ASD children, as well as issues such as children's social lives and self-care routines.
    CONCLUSION: Understandings of how FB is used to seek social support could impact supporting and maintaining effective communication among parents and/or caregivers of children with ASDs. This information could also improve approaches used by health professionals in developing, improving and evaluating social support systems for parents/caregivers.
    Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    KEYWORDS: ASD; Autism; Facebook; Social support; Support group
  17. Manoharan S, Shuib AS, Abdullah N
    PMID: 28573254 DOI: 10.21010/ajtcam.v14i2.39
    BACKGROUND: The commercially available synthetic angiotensin-I-converting enzyme (ACE) inhibitors are known to exert negative side effects which have driven many research groups globally to discover the novel ACE inhibitors.

    METHOD: Literature search was performed within the PubMed, ScienceDirect.com and Google Scholar.

    RESULTS: The presence of proline at the C-terminal tripeptide of ACE inhibitor can competitively inhibit the ACE activity. The effects of other amino acids are less studied leading to difficulties in predicting potent peptide sequences. The broad specificity of the enzyme may be due to the dual active sites observed on the somatic ACE. The inhibitors may not necessarily competitively inhibit the enzyme which explains why some reported inhibitors do not have the common ACE inhibitor characteristics. Finally, the in vivo assay has to be carried out before the peptides as the antihypertensive agents can be claimed. The peptides must be absorbed into circulation without being degraded, which will affect their bioavailability and potency. Thus, peptides with strong in vitro IC50 values do not necessarily have the same effect in vivo and vice versa.

    CONCLUSION: The relationship between peptide amino acid sequence and inhibitory activity, in vivo studies of the active peptides and bioavailability must be studied before the peptides as antihypertensive agents can be claimed.

  18. Salman IM, Sattar MA, Ameer OZ, Abdullah NA, Yam MF, Salman HM, et al.
    Indian J Med Res, 2010 Jun;131:786-92.
    PMID: 20571167
    A wealth of information concerning the essential role of renal sympathetic nerve activity (RSNA) in the regulation of renal function and mean arterial blood pressure homeostasis has been established. However, many important parameters with which RSNA interacts are yet to be explicitly characterized. Therefore, the present study aimed to investigate the impact of acute renal denervation (ARD) on sodium and water excretory responses to intravenous (iv) infusions of either norepinephrine (NE) or angiotensin II (Ang II) in anaesthetized spontaneously hypertensive rats (SHR).
  19. Tijani HI, Abdullah N, Yuzir A, Ujang Z
    Bioresour Technol, 2015 Jun;186:276-85.
    PMID: 25836036 DOI: 10.1016/j.biortech.2015.02.107
    The structural and hydrodynamic features for granules were characterized using settling experiments, predefined mathematical simulations and ImageJ-particle analyses. This study describes the rheological characterization of these biologically immobilized aggregates under non-Newtonian flows. The second order dimensional analysis defined as D2=1.795 for native clusters and D2=1.099 for dewatered clusters and a characteristic three-dimensional fractal dimension of 2.46 depicts that these relatively porous and differentially permeable fractals had a structural configuration in close proximity with that described for a compact sphere formed via cluster-cluster aggregation. The three-dimensional fractal dimension calculated via settling-fractal correlation, U∝l(D) to characterize immobilized granules validates the quantitative measurements used for describing its structural integrity and aggregate complexity. These results suggest that scaling relationships based on fractal geometry are vital for quantifying the effects of different laminar conditions on the aggregates' morphology and characteristics such as density, porosity, and projected surface area.
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