Displaying publications 1 - 20 of 35 in total

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  1. Bakar, M. S. A., Ahmad, S., Muchtar, A., Rahman, H. A .
    MyJurnal
    Solid oxide fuel cells (SOFC) are efficient and clean power generation devices. Lowtemperature
    SOFC (LTSOFC) has been developed since high-temperature SOFC (HTSOFC) is not
    feasible to be commercialized due to cost. Lowering the operation temperature reduces its substantial
    performance resulting from cathode polarization resistance and overpotential of cathode. The
    development of composite cathodes regarding mixed ionic-electronic conductor (MIEC) and ceriabased
    materials for LTSOFC minimizes the problems significantly and leads to an increase in
    electrocatalytic activity for the occurrence of oxygen reduction reaction (ORR). Lanthanum-based
    materials such as lanthanum strontium cobalt ferrite (La0.6Sr0.4Co0.2Fe0.8O3-δ) have been discovered
    recently, which offer great compatibility with ceria-based electrolyte to be applied as composite
    cathode materials for LTSOFC. Cell performance at lower operating temperature can be maintained
    and further improved by enhancing the ORR. This paper reviews recent development of various ceriabased
    composite cathodes especially related to the ceria-carbonate composite electrolytes for
    LTSOFC. The influence of the addition of metallic elements such as silver (Ag), platinum (Pt) and
    palladium (Pd) towards the electrochemical properties and performance of LSCF composite cathodes
    are also discussed.
  2. Syedhussain S, Tan K, Abu Bakar M
    Malays J Nutr, 1996 Mar;2(1):79-86.
    PMID: 22692100
    Our earlier report showed that diet rich in calcium and sodium fed to guinea pigs can be urolithogenic. In this study, we investigated the effect of adding 3% or 15% cellulose as a source of fiber into similar diet to asses the formation of kidney calculus. From the result, animals fed diet with 3% cellulose showed a relatively high concentration of urinary oxalate, urate and large number of crystals in the kidneys. When the cellulose level was raised to 15%, the concentrations of urinary calcium, urate and the number of crystals formed in the kidneys were lowered. We therefore, conclude that high fiber diet may be beneficial in reducing the incidence of kidney stones of calcium origin.
  3. Taha, H., Mohebali, N., Chung, Y. L., Ismail, N. H., Aziz , A., Bakar, M. Z. A., et al.
    MyJurnal
    his is a short report on the recent investigation on the anticancer and antioxidant potential
    of Pseuduvaria macrophylla stem bark and leaf extract on human breast cancer cell (MCF-7), human
    prostate cancer cell (PC-3) and human colon cancer cell (HT29). LCMS experiment was done to
    identify the chemical composition in the methanolic extracts while GCMS analysis was done to
    determine the chemical composition in the hexanolic extracts. For antioxidant activity, the most active
    extract was leaf methanolic with 69.22 % of DPPH inhibition. Additionally, the leaf methanolic extract
    inhibited the better proliferation especially on human breast cancer cell (MCF-7) compared to hexane
    crude extracts due to more than 90% of cancer cell death and lowest IC50 value at range of 80.70
    µg/mL ± 0.08 – 106.70 µg/mL ± 0.07. The major detected compounds were α-Cadinol, neophytadiene,
    palmitic acid, linoleic acid, oleic acid and isopolycerasoidal and isopolycerasoidal methyl ester. The
    findings of this study support the anti-cancer claims of Pseuduvaria macrophylla leaf. Copyright© 2016
    Penerbit Akademia Baru- All rights reserved.
  4. Rahman M, Saniasiaya J, Abu Bakar MZ
    J Laryngol Otol, 2023 Jul;137(7):789-793.
    PMID: 36444560 DOI: 10.1017/S0022215122002493
    OBJECTIVE: Teachers and singers have been extensively studied and are shown to have a greater tendency to voice disorders. This study aimed to investigate the correlation between subjective and objective voice analysis pre- and post-shift among teleoperators in a tertiary hospital.

    METHODS: This was a prospective cohort study. Each patient underwent pre- and post-shift voice analysis.

    RESULTS: Among 42 teleoperators, 28 patients (66.7 per cent) completed all the tests. Female predominance (62 per cent) was noted, with a mean age of 40 years. Voice changes during working were reported by 48.1 per cent. Pre- and post-shift maximum phonation time (p < 0.018) and Voice Handicap Index-10 (p < 0.011) showed significant results with no correlation noted between subjective and objective assessment.

    CONCLUSION: Maximum phonation time and Voice Handicap Index-10 are good voice assessment tools. The quality of evidence is inadequate to recommend 'gold standard' voice assessment until a better-quality study has been completed.

  5. Anis S, Zainal ZA, Bakar MZ
    Bioresour Technol, 2013 May;136:117-25.
    PMID: 23567671 DOI: 10.1016/j.biortech.2013.02.049
    A new effective RF tar thermocatalytic treatment process with low energy intensive has been proposed to remove tar from biomass gasification. Toluene and naphthalene as biomass tar model compounds were removed via both thermal and catalytic treatment over a wide temperature range from 850 °C to 1200 °C and 450 °C to 900 °C, respectively at residence time of 0-0.7 s. Thermal characteristics of the new technique are also described in this paper. This study clearly clarified that toluene was much easier to be removed than naphthalene. Soot was found as the final product of thermal treatment of the tar model and completely removed during catalytic treatment. Radical reactions generated by RF non-thermal effect improve the tar removal. The study showed that Y-zeolite has better catalytic activity compared to dolomite on toluene and naphthalene removal due to its acidic nature and large surface area, even at lower reaction temperature of about 550 °C.
  6. Isahak I, Baharin R, Hakim AS, Abu Bakar M, George E
    Malays J Pathol, 1993 Jun;15(1):85-7.
    PMID: 8277796
    A specific enzyme immunoassay (EIA) for the diagnosis of hepatitis C virus (HCV) infection was developed by recombinant DNA technology. Abbott HCV EIA was used to detect antibody to HCV (anti-HCV) in non-transfused and multiply-transfused thalassemia patients. None of 11 non-transfused patients had anti-HCV but 3 of 52 (5.8%) multiply-transfused patients had anti-HCV. This study showed that the prevalence rate of HCV infection is low in thalassemia patients. However, it is still important to identify hepatitis C virus infected patients in high risk groups because hepatitis C is associated with chronic hepatitis, cirrhosis and hepatocellular carcinoma.
  7. Sarmani S, Kuan LL, Bakar MA
    Biol Trace Elem Res, 1990 7 1;26-27:497-502.
    PMID: 1704755
    Kidney stone samples of the types calcium oxalate, uric acid, and xanthine were analyzed for their elemental contents by neutron activation analysis to study both the elemental correlation and influence of element on stone precipitation processes. Elements, such as Al, Au, Br, Ca, Cl, Co, Cr, Fe, Hg, I, K, Mg, Na, Sb, Se, Sr, and Zn, were determined quantitatively. Calcium oxalate stones contained higher concentration of all the elements analyzed compared to uric acid or xanthine stones. The concentrations of Cl, Fe, K, Na, Sr, and Zn were relatively higher than Au, Co, Cr, and Sb. A positive correlation exists between Ca and Zn, whereas a negative correlation exists between Sr and Ca. Zinc may play an important role in the formation of calcium oxalate stone.
  8. Abdullah FH, Abu Bakar NHH, Abu Bakar M
    J Hazard Mater, 2021 03 15;406:124779.
    PMID: 33338763 DOI: 10.1016/j.jhazmat.2020.124779
    Zinc oxide (ZnO) photocatalysts were successfully synthesized via chemical and green, environmentally-benign methods. The work highlights the valorization of banana peel (BP) waste extract as the reducing and capping agents to produce pure, low temperature, highly crystalline, and effective ZnO nanoparticles with superior photocatalytic activities for the removal of hazardous Basic Blue 9 (BB9), crystal violet (CV), and cresol red (CR) dyes in comparison to chemically synthesized ZnO. Their formation and morphologies were verified by various optical spectroscopic and electron microscopic techniques. XRD results revealed that the biosynthesized ZnO exhibited 15.3 nm crystallite size when determined by Scherrer equation, which was smaller than the chemically synthesized ZnO. The FTIR spectra confirmed the presence of biomolecules in the green-mediated catalyst. EDX and XPS analyses verified the purity and chemical composition of ZnO. Nitrogen sorption analysis affirmed the high surface area of bio-inspired ZnO. Maximum removal efficiencies were achieved with 30 mg green ZnO catalyst, 2.0 × 10-5 M BB9 solution, alkaline pH 12, and irradiation time 90 min. Green-mediated ZnO showed superior photodegradation efficiency and reusability than chemically synthesized ZnO. Therefore, this economical, environment-friendly photocatalyst is applicable for the removal of organic contaminants in wastewater treatment under visible light irradiation.
  9. Thambiah SC, Abu-Bakar M, Bador KM, Das S, Umar NA
    Clin Ter, 2010;161(4):349-54.
    PMID: 20931159
    We report the case of a 37-year-old Chinese man who came with a history of bilateral adrenalectomy and was admitted for recurrent phaeochromocytoma. Further investigations of an incidental finding of persistently raised carcinoembryonic antigen (CEA), fi rst observed four years ago, revealed medullary thyroid carcinoma (MTC). As such, a provisional diagnosis of Multiple Endocrine Neoplasia 2A (MEN 2A) was made. In this case, it seemed like the long-standing elevation of CEA was ignored until it was noted in a post-clinical discussion among several physicians. The present case illustrates the significance of considering a single abnormal biochemical test in an asymptomatic patient and also discusses the importance of life-long follow-up of a patient with a history of phaeochromocytoma.
  10. Shah Bakhtiar N, Akmam A Bakar M, Abdullah Z, Ng SW
    PMID: 21583574 DOI: 10.1107/S1600536809026592
    In the title compound, C(14)H(10)N(2)O, the organic rings are inclined at an angle of 86.1 (1)°. The angle at the ether O atom is widened to 117.18 (14)°.
  11. Abu Bakar NH, Abu Bakar M, Bettahar MM, Ismail J, Monteverdi S
    J Nanosci Nanotechnol, 2013 Jul;13(7):5034-43.
    PMID: 23901527
    A detailed study on the surface properties of oleic acid-stabilized PtNi nanoparticles supported on silica is reported. The oleic acid-stabilized PtNi nanoparticles were synthesized using NaBH4 as the reducing agent at various temperatures and oleic acid concentrations, prior to incorporation onto the silica support. X-ray diffraction studies of the unsupported oleic acid-stabilized PtNi particles revealed that the PtNi existed as alloys. Upon incorporation onto silica support, surface properties of the catalysts were investigated using H2-temperature reduction (H2-TPR), H2-temperature desorption (H2-TPD) and H2-chemisorption techniques. It was found that for the bimetallic catalysts, no oxides or very little oxidation occurred. Furthermore, these catalysts exhibited both Pt and Ni active sites on its surface though the availability of Ni active sites was dominant. A comparison of the surface properties of these materials with those prepared without oleic acid in our previous work [N. H. H. Abu Bakar et al., J. Catal. 265, 63 (2009)] and how they affect the hydrogenation of benzene is also discussed.
  12. Siew WY, Abu Bakar NHH, Abu Bakar M, Zainal Abidin A
    J Hazard Mater, 2021 Aug 15;416:125846.
    PMID: 34492799 DOI: 10.1016/j.jhazmat.2021.125846
    The incorporation of different percentages of Fe2+ into copper benzene-1,3,5-tricarboxylate (CuBTC) was successfully carried out at room-temperature synthesis with water as the only solvent. The XRD and XPS analysis shows that the Fe2+ were substituted into the paddlewheel structure. The incorporation of 18% Fe2+ into CuBTC can increase the surface area and porosity of the framework. The BET surface area of Cu82Fe18BTC (1240 m2/g) was significantly higher than CuBTC (708 m2/g). Further increase in the Fe2+ percentage will reduce the surface area of the compound. The presence of Fe2+ in the framework successfully disturbs the pore formation and widens the pore size on the surface of these compounds. This as well as the pHpzc, which is related to the surface acidity of the resulting bimetallic organic framework (BMOF), play an important role in the adsorption process. Cu53Fe47BTC with an adsorption capacity of 94.42 mg/g shows approximately 6 times greater adsorption capacity against MB compared to CuBTC. This shows that by utilizing a different ratio of Cu and a second metal, it is possible to effectively design the surface morphology of BMOF for specific applications.
  13. Ngui LX, Wong LS, Shashi G, Abu Bakar MN
    J Laryngol Otol, 2017 Sep;131(9):830-833.
    PMID: 28412984 DOI: 10.1017/S0022215117000834
    OBJECTIVE: This paper reports on a non-conventional method for the management of facial carbuncles, highlighting its superiority over conventional surgical treatment in terms of cosmetic outcome and shorter duration of wound healing.

    BACKGROUND: The mainstay of treatment for carbuncles involves the early administration of antibiotics in combination with surgical intervention. The conventional saucerisation, or incision and drainage, under normal circumstances results in moderate to large wounds, which may need secondary surgery such as skin grafting, resulting in a longer duration of wound healing and jeopardising cosmetic outcome.

    CASE REPORTS: The reported three cases presented with extensive carbuncles over the chin, face and lips region. In addition to early commencement of intravenous antibiotics, the pus was drained, with minimal incision and conservative wound debridement, with the aim of maximal skin conservation. This was followed by thrice-daily irrigation with antibiotic-containing solution for a minimum of 2 consecutive days. The wounds healed within two to four weeks, without major cosmetic compromise.

    CONCLUSION: The new method showed superior cosmetic outcomes, with a shorter duration of wound healing. Conservative surgical management can be performed under regional anaesthesia, which may reduce morbidity and mortality; patients with facial carbuncles often have higher risks with general anaesthesia.

  14. Haque M, McKimm J, Godman B, Abu Bakar M, Sartelli M
    Expert Rev Anticancer Ther, 2019 01;19(1):81-92.
    PMID: 30394844 DOI: 10.1080/14737140.2019.1544497
    Introduction: Surgery in patients with head and neck cancers is frequently complicated by multiple stages of procedure that includes significant surgical removal of all or part of an organ with cancer, tissue reconstruction, and extensive neck dissection. Postoperative wound infections, termed 'surgical site infections' (SSIs) are a significant impediment to head-and-neck cancer surgery and recovery, and need to be addressed. Areas covered: Approximately 10-45% of patients undergoing head-and-neck cancers surgery develop SSIs. SSIs can lead to delayed wound healing, increased morbidity and mortality as well as costs. Consequently, SSIs need to be avoided where possible, as even the surgery itself impacts on patients' subsequent activities and their quality of life, which is exacerbated by SSIs. Several risk factors for SSIs need to be considered to reduce future rates, and care is also needed in the selection and duration of antibiotic prophylaxis. Expert commentary: Head and neck surgeons should give personalized care especially to patients at high risk of SSIs. Such patients include those who have had chemoradiotherapy and need reconstructive surgery, and patients from lower and middle-income countries and from poorer communities in high income countries, who often have high levels of co-morbidity because of resource constraints.
  15. Omer ME, Abu Bakar M, Adam M, Mustafa M
    Asian Pac J Cancer Prev, 2021 Apr 01;22(4):1045-1053.
    PMID: 33906295 DOI: 10.31557/APJCP.2021.22.4.1045
    OBJECTIVE: Cure rate models are survival models, commonly applied to model survival data with a cured fraction. In the existence of a cure rate, if the distribution of survival times for susceptible patients is specified, researchers usually prefer cure models to parametric models. Different distributions can be assumed for the survival times, for instance, generalized modified Weibull (GMW), exponentiated Weibull (EW), and log-beta Weibull. The purpose of this study is to select the best distribution for uncured patients' survival times by comparing the mixture cure models based on the GMW distribution and its particular cases.

    MATERIALS AND METHODS: A data set of 91 patients with high-risk acute lymphoblastic leukemia (ALL) followed for five years from 1982 to 1987 was chosen for fitting the mixture cure model. We used the maximum likelihood estimation technique via R software 3.6.2 to obtain the estimates for parameters of the proposed model in the existence of cure rate, censored data, and covariates. For the best model choice, the Akaike information criterion (AIC) was implemented.

    RESULTS: After comparing different parametric models fitted to the data, including or excluding cure fraction, without covariates, the smallest AIC values were obtained by the EW and the GMW distributions, (953.31/969.35) and (955.84/975.99), respectively. Besides, assuming a mixture cure model based on GMW with covariates, an estimated ratio between cure fractions for allogeneic and autologous bone marrow transplant groups (and its 95% confidence intervals) were 1.42972 (95% CI: 1.18614 - 1.72955).

    CONCLUSION: The results of this study reveal that the EW and the GMW distributions are the best choices for the survival times of Leukemia patients.
    .

  16. Abdullah FH, Bakar NHHA, Bakar MA
    J Hazard Mater, 2022 Feb 15;424(Pt B):127416.
    PMID: 34655867 DOI: 10.1016/j.jhazmat.2021.127416
    Industrial wastewaters contain hazardous contaminants that pollute the environment and cause socioeconomic problems, thus demanding the employment of effective remediation procedures such as photocatalysis. Zinc oxide (ZnO) nanomaterials have emerged to be a promising photocatalyst for the removal of pollutants in wastewater owing to their excellent and attractive characteristics. The dynamic tunable features of ZnO allow a wide range of functionalization for enhanced photocatalytic efficiency. The current review summarizes the recent advances in the fabrication, modification, and industrial application of ZnO photocatalyst based on the analysis of the latest studies, including the following aspects: (1) overview on the properties, structures, and features of ZnO, (2) employment of dopants, heterojunction, and immobilization techniques for improved photodegradation performance, (3) applicability of suspended and immobilized photocatalytic systems, (4) application of ZnO hybrids for the removal of various types of hazardous pollutants from different wastewater sources in industries, and (5) potential of bio-inspired ZnO hybrid nanomaterials for photocatalytic applications using renewable and biodegradable resources for greener photocatalytic technologies. In addition, the knowledge gap in this field of work is also highlighted.
  17. Raman K, Govindaraju R, James K, Abu Bakar MZ, Patil N, Shah MN
    J Laryngol Otol, 2023 Feb;137(2):169-173.
    PMID: 34924062 DOI: 10.1017/S0022215121004175
    OBJECTIVE: Knowledge of anatomical variations of the frontal recess and frontal sinus and recognition of endoscopic landmarks are vital for safe and effective endoscopic sinus surgery. This study revisited an anatomical landmark in the frontal recess that could serve as a guide to the frontal sinus.

    METHOD: Prevalence of the anterior ethmoid genu, its morphology and its relationship with the frontal sinus drainage pathway was assessed. Computed tomography scans with multiplanar reconstruction were used to study non-diseased sinonasal complexes.

    RESULTS: The anterior ethmoidal genu was present in all 102 anatomical sides studied, independent of age, gender and race. Its position was within the frontal sinus drainage pathway, and the drainage pathway was medial to it in 98 of 102 cases. The anterior ethmoidal genu sometimes extended laterally and formed a recess bounded by the lamina papyracea laterally, by the uncinate process anteriorly and by the bulla ethmoidalis posteriorly. Distance of the anterior ethmoidal genu to frontal ostia can be determined by the height of the posterior wall of the agger nasi cell rather than its volume or other dimensions.

    CONCLUSION: This study confirmed that the anterior ethmoidal genu is a constant anatomical structure positioned within frontal sinus drainage pathway. The description of anterior ethmoidal genu found in this study explained the anatomical connection between the agger nasi cell, uncinate process and bulla ethmoidalis and its structural organisation.

  18. Haque M, Sartelli M, McKimm J, Abu Bakar M
    Infect Drug Resist, 2018;11:2321-2333.
    PMID: 30532565 DOI: 10.2147/IDR.S177247
    Health care-associated infections (HCAIs) are infections that occur while receiving health care, developed in a hospital or other health care facility that first appear 48 hours or more after hospital admission, or within 30 days after having received health care. Multiple studies indicate that the common types of adverse events affecting hospitalized patients are adverse drug events, HCAIs, and surgical complications. The US Center for Disease Control and Prevention identifies that nearly 1.7 million hospitalized patients annually acquire HCAIs while being treated for other health issues and that more than 98,000 patients (one in 17) die due to these. Several studies suggest that simple infection-control procedures such as cleaning hands with an alcohol-based hand rub can help prevent HCAIs and save lives, reduce morbidity, and minimize health care costs. Routine educational interventions for health care professionals can help change their hand-washing practices to prevent the spread of infection. In support of this, the WHO has produced guidelines to promote hand-washing practices among member countries.
  19. Muda NE, Abu Bakar MA, Majlis BY
    Malays J Med Sci, 1999 Jul;6(2):12-6.
    PMID: 22589683 MyJurnal
    The development of antibody-based biosensor has grown steadily during recent years, and their use as a routine instrument in clinical application is not far from reality. This study has demonstrated the capability of conductometric sensor to quantitate human Follicle Stimulating Hormone (hFSH) from urine samples. The principles are adopted from Enzyme Linked Immunosorbent Assay (ELISA) technique. Self fabricated gold coated electrode was dipped in the microtiter well containing antibody-antigen complex. Substrate was added to the system to initiate a secondary reaction, which produced electroactive species and change the conductivity of the solution. The changes were proportional with the concentration of the hormone present. The results obtained correlate well with the conventional ELISA technique. Inter and intra assay variation (%CV) were under 6% and the lowest detection limit is 0.75 mIU/ml which was well under the physiological range of the hormone. This system offered advantages such as simplicity, reliability, minimal addition of reagents, freedom from turbidity and color problem, probability of miniaturizing the electrode thus minimizing the sample volume and the ability of on line data analysis. This study proved that Antigen-Antibody reaction via EIA could be detected electronically and it has a potential to be used as one of the measuring mode in clinical analysis.
  20. Seddighi Chaharborj S, Seddighi Chahrborj S, Sadat Kiai SM, Abu Bakar MR, Ziaeian I, Gheisari Y
    J Mass Spectrom, 2012 Apr;47(4):484-9.
    PMID: 22689625 DOI: 10.1002/jms.2041
    The homotopy analysis method (HAM) is applied to study the behavior of a hyperbolic rods of quadrupole mass filter and a sinusoidal potential form V(ac)  cos(Ωt). Numerical computation method of a 20th-order HAM is employed to compare the physical properties of the confined ions with fifth-order Runge-Kutta method. Also, comparison is made for the first stability region, the ion trajectories in real time, the polar plots, and the ion trajectory in x - y plan. The results show that the two methods are fairly similar; therefore, the HAM method has potential application to solve linear and nonlinear equations of the charge particle confinement in quadrupole field.
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