Displaying publications 1 - 20 of 140 in total

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  1. Abd Rahman S, Ariffin N, Yusof NA, Abdullah J, Mohammad F, Ahmad Zubir Z, et al.
    Sensors (Basel), 2017 Jul 01;17(7).
    PMID: 28671559 DOI: 10.3390/s17071537
    A semiconducting water-soluble core-shell quantum dots (QDs) system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction). The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM) and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10-12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L-cysteine, L-histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA), mercapto-propionic acid (MPA), mercapto-succinic acid (MSA), and mercapto-undecanoic acid (MUA). This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA) exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.
  2. Abdul Latip LS, Ahmad Alias NA, Ariff AR, Shuaib IL, Abdullah J, Naing NN
    J Clin Neurosci, 2004 Nov;11(8):835-9.
    PMID: 15519858 DOI: 10.1016/j.jocn.2003.12.017
    Minor head injury in a developing country like Malaysia is managed by primary care physicians and/or medical assistants in district hospitals. These patients are seen initially in their local hospitals, which have at least an X-ray machine for the purpose of screening. This study aimed to guide these physicians to manage these patients at a primary care level. A cross-sectional study was conducted and the study revealed significant predictors of significant computed tomographic (CT) findings. The presence of a Glasgow coma scale (GCS) score of 14 or 13 was associated with the risk of developing significant CT findings compared to patients with a GCS of 15 (p<0.001). Thirty-seven out of 50 patients with GCS of 14 or 13 developed clinically significant brain injury on CT scan. Similarly, the presence of skull fracture was associated with the risk of developing CT abnormalities (p<0.001). Forty-two out of 51 patients with skull fracture developed clinically significant CT findings. Vomiting was associated with developing CT abnormalities (p=0.017). Twenty-seven out of 40 patients with vomiting showed significant CT findings. Soft tissue injury was also found to be associated with developing CT abnormalities (p=0.007). Therefore, we propose reclassifying minor head injury based on the GCS score. Patients with a GCS score of 15 were classified as having mild head injury, while patients with a GCS score of 13 or 14 were at higher risk of developing brain injury and therefore categorized as high risk mild head injury. This group requires emergency CT scan examination, especially when associated with non-motor vehicle accidents, abnormal central nervous system (CNS) examination, craniofacial injuries or skull fractures. They should be referred to a general surgical unit which can treat head injuries or a neurosurgical tertiary centre.
  3. Abdul Rashid JI, Yusof NA, Abdullah J, Shomiad Shueb RH
    RSC Adv, 2023 Jun 15;13(27):18748-18759.
    PMID: 37362605 DOI: 10.1039/d3ra00216k
    In recent years, limited research has been conducted on enhancing DNA hybridization-based biosensor approaches using statistical models. This study explores the application of response surface methodology (RSM) to improve the performance of a DNA hybridization biosensor for dengue virus (DENV) detection. The biosensor is based on silicon nanowires decorated with gold nanoparticles (SiNWs/AuNPs) and utilizes methylene blue as a redox indicator. The DNA hybridization process between the immobilized DNA probe and the target DENV gene was monitored using differential pulse voltammetry (DPV) based on the reduction of methylene blue. Fourier-transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS) were employed to confirm successful DNA hybridization events on the modified screen-printed gold electrode (SPGE) surface. Several parameters, including pH buffer, NaCl concentration, temperature, and hybridization time, were simultaneously optimized, with NaCl concentration having the most significant impact on DNA hybridization events. This study enhances the understanding of the role of each parameter in influencing DNA hybridization detection in electrochemical biosensors. The optimized biosensor demonstrated the ability to detect complementary oligonucleotide and amplified DENV gene concentrations as low as 0.0891 ng µL-1 (10 pM) and 2.8 ng µL-1, respectively. The developed biosensor shows promise for rapid clinical diagnosis of dengue virus infection.
  4. Abdul Rashid JI, Yusof NA, Abdullah J, Shomiad Shueb RH
    RSC Adv, 2021 Dec 20;12(1):1-10.
    PMID: 35424522 DOI: 10.1039/d1ra06753b
    The application of electrochemical DNA biosensors in real genomic sample detection is challenging due to the existence of complex structures and low genomic concentrations, resulting in inconsistent and low current signals. This work highlights strategies for the treatment of non-amplified and amplified genomic dengue virus gene samples based on real samples before they can be used directly in our DNA electrochemical sensing system, using methylene blue (MB) as a redox indicator. The main steps in this study for preparing non-amplified cDNA were cDNA conversion, heat denaturation, and sonication. To prepare amplified cDNA dengue virus genomic samples using an RT-PCR approach, we optimized a few parameters, such as the annealing temperature, sonication time, and reverse to forward (R/F) primer concentration ratio. We discovered that the generated methylene blue (MB) signals during the electrochemical sensing of non-amplified and amplified samples differ due to the different MB binding affinities based on the sequence length and base composition. The findings show that our developed electrochemical DNA biosensor successfully discriminates MB current signals in the presence and absence of the target genomic dengue virus, indicating that both samples were successfully treated. This work also provides interesting information about the critical factors in the preparation of genomic gene samples for developing miniaturized PCR-based electrochemical sensing applications in the future. We also discuss the limitations and provide suggestions related to using redox-indicator-based electrochemical biosensors to detect real genomic nucleic acid genes.
  5. Abdullah J, Saffie N, Sjasri FA, Husin A, Abdul-Rahman Z, Ismail A, et al.
    Braz J Microbiol, 2014;45(4):1385-91.
    PMID: 25763045
    An in-house loop-mediated isothermal amplification (LAMP) reaction was established and evaluated for sensitivity and specificity in detecting the presence of Salmonella Typhi (S. Typhi) isolates from Kelantan, Malaysia. Three sets of primers consisting of two outer and 4 inner were designed based on locus STBHUCCB_38510 of chaperone PapD of S. Typhi genes. The reaction was optimised using genomic DNA of S. Typhi ATCC7251 as the template. The products were visualised directly by colour changes of the reaction. Positive results were indicated by green fluorescence and negative by orange colour. The test was further evaluated for specificity, sensitivity and application on field samples. The results were compared with those obtained by gold standard culture method and Polymerase Chain Reaction (PCR). This method was highly specific and -10 times more sensitive in detecting S. Typhi compared to the optimised conventional polymerase chain reaction (PCR) method.
  6. Abdullah J, Ahmad M, Heng LY, Karuppiah N, Sidek H
    Talanta, 2006 Oct 15;70(3):527-32.
    PMID: 18970803 DOI: 10.1016/j.talanta.2005.12.061
    The development of an optical biosensor based on immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and tyrosinase in chitosan film for the detection of phenolic compounds has been described. Tyrosinase was immobilized in chitosan film deposited on the hybrid nafion/sol-gel silicate film containing MBTH. The enzymatic oxidation product of phenolic compounds were stabilized through formation of adduct with MBTH to produce a maroon color adduct. The color intensity of adduct was found to increase proportionally with the increase of the substrate concentrations after 5min exposure. The linearity of the biosensor towards phenol, catechol and m-cresol were in the respective concentration range of 0.5-7.0, 0.5-10.0 and 1.0-13.0mg/L with detection limit of 0.18, 0.23 and 0.43mg/L, respectively. The biosensor shows a good stability for at least 3 months.
  7. Abdullah J, Ahmad M, Heng LY, Karuppiah N, Sidek H
    Anal Bioanal Chem, 2006 Nov;386(5):1285-92.
    PMID: 17031625
    The stacked-film immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and horseradish peroxidase (HRP) in chitosan, performed in order to allow the determination of phenolic compounds, was investigated via an optical method. The stacked films were deposited onto a microscope glass slide by a spin-coating technique. The quinone or free radical product formed by the enzymatic reactions of phenolic compounds interacts with MBTH to form azo-dye products, which can be measured spectrophotometrically at a wavelength of 500 nm. The color intensity of the product was found to increase in proportion to the phenolic concentration after 5 min of exposure. The response of the biosensor was linear over concentration ranges of 0.025-0.500, 0.010-0.070 and 0.050-0.300 mM for guaiacol, resorcinol and o-cresol, respectively, and gave detection limits of 0.010, 0.005 and 0.012 mM. The sensor exhibited good sensitivity and stability for at least two months.
  8. Abdullah J, Zamzuri I, Awang S, Sayuthi S, Ghani A, Tahir A, et al.
    Acta Neurochir. Suppl., 2005;95:311-4.
    PMID: 16463872
    The monitoring of craniospinal compliance is uncommonly used clinically despite it's value. The Spiegelberg compliance monitor calculates intracranial compliance (C = deltaV/deltaP) from a moving average of small ICP perturbations (deltaP) resulting from a sequence of up to 200 pulses of added volume (deltaV = 0.1 ml, total V = 0.2 ml) made into a double lumen intraventricular balloon catheter. The objective of this study was thus to determine the effectiveness of the decompressive craniectomy done on the worst brain site with regard to compliance (Cl), pressure volume index (PVI), jugular oximetry (SjVo2), autoregulation abnormalties, brain tissue oxygen (TiO2) and cerebral blood flow (CBF). This is a prospective cohort study of 17 patients who were enrolled after consent and approval of the ethics committee between the beginning of the year 2001 and end of the year 2002. For pre and post assessment on compliance and PVI, all 12 patients who survived were reported to become normal after decompressive craniectomy. There is no significant association between pre and post craniectomy assessment in jugular oxymetry (p > 0.05), autoregulation (p > 0.05), intracranial brain oxymetry (p = 0.125) and cerebral blood flow (p = 0.375). Compliance and PVI improved dramatically in all alive patients who received decompressive craniectomy. Compliance and PVI monitoring may be crucial in improving the outcome of severe head injured patients after decompressive craniectomy.
  9. Abdullah J, Ariff AR, Ghazaime G, Naing NN
    Stereotact Funct Neurosurg, 2001;76(3-4):175-80.
    PMID: 12378096
    The beneficial effects of stereotactic third ventriculostomy versus ventriculoperitoneal shunt were evaluated in 62 paediatric patients and analysed in relation to age, sex, clinical history, presence of meningomyelocele, magnetic resonance imaging measurements of hydrocephalus and third ventricle floor size. The third ventriculostomy were done on 50 patients using the Richard-Wolf Caemaert Endoscope and the Leksell Stereotactic Frame Model G. These patients were operated using the 4-French Fogarty catheter to open the base of the third ventricle. During the same period of study 12 paediatric patients with aqueduct stenosis who were managed by ventriculoperitoneal shunt were included. Both surgical procedures were compared. Statistically univariate analysis revealed that those patient with an age group of more than six months undergoing ventriculostomy had good outcome. Multivariate analysis revealed that past history of haemorrhage and/or meningitis were predictors of poor outcome. Sex, size of lumbar meningocele at birth, abnormal ventricular anatomy or narrow third ventricular floor size were non predictors of bad outcome in these patients. There was no difference in outcome in both the shunt or ventriculostomy group.
  10. Abdullah J, Rushdan A, Hamzah M, Ariff AR, Rani A
    Ann. Transplant., 1999;4(3-4):28-31.
    PMID: 10853777
    Four patients underwent reconstruction of anterior cranial fossa of skull defects between November 1997 and January 1998. All of them had traumatic anterior cranial fossa defect and were reconstructed with lyophilised bovine cortical bone graft. There was no cerebrospinal fluid leakage, meningitis, extradural abscess or other infections. This study demonstrates that the use of bovine bone graft in the reconstruction of anterior base defects is safe.
  11. Abdullah J, Isa MN
    Stereotact Funct Neurosurg, 1999;73(1-4):19-22.
    PMID: 10853092
    Two hundred primary brain tumours in both adults and children from the year 1990 to 1998 presenting for treatment to the Neurosurgical Division of the Hospital of the University of Sciences Malaysia were studied retrospectively. Volumes of tumours were taken from CT scans with contrast using two formulas and divided into 4 groups: (1) less than 20 cm(3), (2) 20-50 cm(3), (3) 50-100 cm(3) (4) larger than 100 cm(3). The majority of the brain tumours were in the volume range of 50-100 cm(3), and are thus potentially curable with retroviral gene therapy.
  12. Abdullah J
    J Clin Neurosci, 2001 Jan;8(1):18-22.
    PMID: 11322120
    Sixty patients with brain abscess were treated at the Neurosurgical Unit of the Department of Surgery, Hospital Universiti Sains Malaysia between January 1990 and December 1996. A retrospective study was done and data were collected from the computerise d registry of the Record Unit of Hospital Universiti Sains Malaysia. Good results were achieved in patients who were both treated surgically and medically. There were only twelve deaths in this group. The main factor that influences morbidity and mortality of brain abscess is the clinical presentation on admission. The mortality was high in patients treated solely by medical means. Death was common in patients who presented with acute onset of symptoms of less than one week duration and those with poor mental status. Brain abscess is common in the East Coast population of peninsular Malaysia, probably due in part to lower socioeconomic status. Efforts should be directed towards prevention of infection and early recognition and management.
  13. Abdullah J, Ridzuan MY
    Stereotact Funct Neurosurg, 1997;69(1-4 Pt 2):152-5.
    PMID: 9711749
    This is a descriptive epidemiologic study that was done retrospectively for the years 1990-1996. The objective was to determine whether tumours less than 4 cm in diameter are common and thereafter suitable for radiosurgical treatment. The results showed that the incidence of brain tumours less than 4 cm in diameter was 73.3% and about 20% were situated in the eloquent area.
  14. Abdullah J, Ahmad M, Heng LY, Karuppiah N, Sidek H
    Sensors (Basel), 2007 Oct 11;7(10):2238-2250.
    PMID: 28903224 DOI: 10.3390/s7102238
    The fabrication of an optical biosensor by using stacked films where 3-methyl-2-benzothiazolinone hydrazone (MBTH) was immobilized in a hybrid nafion/sol-gelsilicate film and laccase in a chitosan film for the detection of phenolic compounds wasdescribed. Quinone and/or phenoxy radical product from the enzymatic oxidation ofphenolic compounds was allowed to couple with MBTH to form a colored azo-dye productfor spectrophometric detection. The biosensor demonstrated a linear response to catecholconcentration range of 0.5-8.0 mM with detection limit of 0.33 mM and response time of10 min. The reproducibility of the fabricated biosensor was good with RSD value of 5.3 %(n = 8) and stable for at least 2 months. The use of the hybrid materials of nafion/sol-gelsilicate to immobilize laccase has altered the selectivity of the enzyme to various phenoliccompounds such as catechol, guaicol, o-cresol and m-cresol when compared to the non-immobilized enzyme. When immobilized in this hybrid film, the biosensor response onlyto catechol and not other phenolic compounds investigated. Immobilization in this hybridmaterial has enable the biosensor to be more selective to catechol compared with the non-immobilized enzyme. This shows that by a careful selection of different immobilizationmatrices, the selectivity of an enzyme can be modified to yield a biosensor with goodselectivity towards certain targeted analytes.
  15. Abdullah J, Naing NN
    Pediatr Neurosurg, 2001 Jan;34(1):13-9.
    PMID: 11275782
    There are few local statistics on the incidence of hydrocephalus and the outcome of hydrocephalic shunts in the South East Asian region. We report a retrospective study on 285 hydrocephalic patients who underwent shunting procedures between 1990 and 1998 at the University Hospital Science Malaysia, a regional referral center. Multiple logistic regression analysis was applied to predict determinants of outcome in relation to the timing of diagnosis, other congenital abnormalities associated with the hydrocephalus, timing of surgery and cortical thickness from CT scan. The relationship of shunt infection was correlated to the age of the patient and surgical procedure. The predictors for developmental outcome reported by this study were age at diagnosis, type of brain abnormalities and gender. Time of operation and cortical thickness did not contribute to the outcome.
  16. Abdullah J, Abdullah MR
    Malays J Med Sci, 2003 Jan;10(1):74-7.
    PMID: 23365504 MyJurnal
    There is no report in the English literature on the criteria for neuroablation or neuroaugmentation for the treatment of Parkinson's disease in a developing country like Malaysia. A prospective study of patients with Parkinson's disease from the north-eastern peninsular Malaysia was done to assess their suitability of surgery. Age, race, duration of illness and dementia were considered important factors towards the success of such surgical procedures. A mathematical model is suggested for future cases deemed to be suitable for neuroaugmentative or ablative surgery.
  17. Abdullah JM, Rahman ZA, Ariff AR, Jaafar H, Phang KS
    Singapore Med J, 2004 Jun;45(6):286-8.
    PMID: 15181525
    Rhabdoid tumour is a rare childhood tumour with poor prognosis. We report a 13-month-old Malay girl suffering from this tumour that was located at the left fronto-temporo-parietal region of the brain. Computed tomography showed a large irregular enhancing mass that caused obstructive hydrocephalus. The tumour did not reduce in size after three operations and finally the patient succumbed to the disease four months after diagnosis.
  18. Abu N, Chinnathambi S, Kumar M, Etezadi F, Bakhori NM, Zubir ZA, et al.
    RSC Adv, 2023 Sep 18;13(40):28230-28249.
    PMID: 37753403 DOI: 10.1039/d3ra05840a
    Over recent years, carbon quantum dots (CQDs) have advanced significantly and gained substantial attention for their numerous benefits. These benefits include their simple preparation, cost-effectiveness, small size, biocompatibility, bright luminescence, and low cytotoxicity. As a result, they hold great potential for various fields, including bioimaging. A fascinating aspect of synthesizing CQDs is that it can be accomplished by using biomass waste as the precursor. Furthermore, the synthesis approach allows for control over the physicochemical characteristics. This paper unequivocally examines the production of CQDs from biomass waste and their indispensable application in bioimaging. The synthesis process involves a simple one-pot hydrothermal method that utilizes biomass waste as a carbon source, eliminating the need for expensive and toxic reagents. The resulting CQDs exhibit tunable fluorescence and excellent biocompatibility, making them suitable for bioimaging applications. The successful application of biomass-derived CQDs has been demonstrated through biological evaluation studies in various cell lines, including HeLa, Cardiomyocyte, and iPS, as well as in medaka fish eggs and larvae. Using biomass waste as a precursor for CQDs synthesis provides an environmentally friendly and sustainable alternative to traditional methods. The resulting CQDs have potential applications in various fields, including bioimaging.
  19. Aferka, S., Abdullah, J., Olujic, Z., Saroha, A.K., Crine, M., Toye, D., et al.
    MyJurnal
    This work focuses on the use of X-ray tomography in investigating the flow distribution in a structured packed bed. Cross sections of the liquid hold up distribution in a 10 cm diameter column packed with Katapak-SP12 are obtained at various column heights for different liquid flow rates. The repartition of the liquid hold up between baskets and corrugated sheets is quantified. Wall wipers and column wall effects are visualized. Results are obtained from an initially dry column without gas flow.
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