Displaying publications 1 - 20 of 61 in total

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  1. Abdul Aziz, A, Ahmad, S.F., Muslim, Y.R
    Ann Dent, 2006;13(1):34-38.
    MyJurnal
    This clinical case report details the clinical sequence of a 78-year-old male receiving prosthetic rehabilitation using an implant-supported screwretained fixed partial denture. Despite the limitations imposed, the aesthetic and functional demands of the patient were fulfilled by this prosthetic rehabilitation. The importance of detailed prosthetic planning and evaluation prior to implant surgery is essential, therefore ideally, it should be done by the same operator or a team of operators working together. Problems can arise when the construction of the prosthesis is performed by other people who are not involved in the planning stage.
  2. Abdul Aziz, A., Abu Kasim, N.H., Ramasindarum, C., Mohamad Yusof, M.Y.P., Paiizi, M., Ahmad, R.
    Ann Dent, 2011;18(1):1-7.
    MyJurnal
    The aim of this study was to assess the wear of tungsten carbide burs and round rotary diamond instruments through measurements of rake angle and visual observations respectively under a field emission scanning electron microscope. Sixty short and long head pear-shaped tungsten carbide burs and 18 round rotary diamond instruments that had been used to complete < 5, > 5 and > 10 cavity preparations (n=10/group) were selected from the 3rd and 4th year dental students, Faculty of Dentistry, University of Malaya. There were two control groups consisting of long and short tungsten carbide burs of ten each. Two-way ANOVA was used to analyse the rake angle data. The data from the two control groups were collectively analysed following multiple paired t-test (p>.05) which showed no significant difference between the two types of tungsten carbide bur (short and long head). The mean rake angle of the control group was significantly higher (p < .05) compared to the < 5, > 5 and > 10 cavity preparation groups. The rake angle of the > 10 cavity preparation group was significantly lower than the other two test groups (p < .05). Round rotary diamond instruments in the < 5 cavity preparation group showed intact diamond particles with distinct cutting facets comparable to the control group. However, diamonds instruments in the > 5 and > 10 cavity preparation groups showed blunt diamond particles. In conclusion, wear of tungsten carbide burs and round rotary diamond instruments were evident after repeated use. Wear was more pronounced when instruments were used to prepare more than ten cavities.
  3. Kamal N, Nizam S, Abdul Aziz A
    Appl Radiat Isot, 2024 Jan;203:111085.
    PMID: 37924626 DOI: 10.1016/j.apradiso.2023.111085
    In this study, the theoretical cross sections of 209Bi(α,2n)211At, 65Cu(α,n)68Ga, 100Ru(α,n)103Pd, and 121Sb(α,n)124I are calculated using TALYS 1.96, incorporating the effects of the alpha optical model potential and nuclear level density models. The validation process involves comparing the calculated cross sections with experimental data and utilizing statistical deviation factors. This comparison allows us to determine the optimal combination of nuclear model parameters for each reaction. The result shows that theoretical calculations which utilized semi microscopic level density models and alpha OMP managed to describe the excitation functions close to the experimental data. The comparison of nuclear model calculations with experimental data plays a crucial role in ensuring the reliability of the data, making it an essential aspect of modern evaluation procedures.
  4. Baroutian S, Aroua MK, Raman AA, Sulaiman NM
    Bioresour Technol, 2011 Jan;102(2):1095-102.
    PMID: 20888219 DOI: 10.1016/j.biortech.2010.08.076
    In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor.
  5. Sodipo BK, Abdul Aziz A
    Ultrason Sonochem, 2015 Mar;23:354-9.
    PMID: 25315418 DOI: 10.1016/j.ultsonch.2014.09.011
    A non-seeded method of incorporating superparamagnetic iron oxide nanoparticles (SPION) into silica nanoparticles is presented. Mixture of both SPION and silica nanoparticles was ultrasonically irradiated. The collapsed bubbles and shockwave generated from the ultrasonic irradiation produce tremendous force that caused inelastic collision and incorporation of SPION into the silica. Physicochemical analyses using transmission electron microscope (TEM), electronic spectroscopic imaging (ESI), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy demonstrated the formation of SPION/silica composite nanoparticles. The prepared composite nanoparticles exhibited superparamagnetic behaviour and nearly 70% of the initial saturation magnetization (Ms) of the SPION was retained. The presence and reactivity of the silica were demonstrated via assembling decanethiol monolayer on the composite nanoparticles. The silanol group of the silica provided the binding site for the alkyl group in the decanethiol molecules. Therefore, the thiol moiety became the terminal and functional group on the magnetic composite nanoparticles.
  6. Razab R, Abdul-Aziz A
    Nat Prod Commun, 2010 Mar;5(3):441-5.
    PMID: 20420325
    Plants that contain high amounts of polyphenolic compounds are potential candidates for natural antioxidant sources. Studies are on going in the search for new sources of antioxidants. Not much data are available on the antioxidant capacity of tropical herbs. With this in mind, 19 commonly consumed Malaysian herbs were analyzed for their polyphenolic content and antioxidant activities. A majority of these plants have never been studied before with regards to their polyphenolic content and antioxidant activities. The shoots of Anacardium occidentale, the shoots and fruits of Barringtonia racemosa, Pithecellobium jiringa and Parkia speciosa had high polyphenolic contents (> 150 microg gallic acid equivalents/mg dried plant) and antioxidant activities when measured using the ferric reducing antioxidant power (FRAP) (>1.2 mM) and Trolox equivalent antioxidant capacity (TEAC) assays (>2.4 mM). A strong correlation was observed between the two antioxidant assays (FRAP vs TEAC) implying that the plants could both scavenge free radicals and reduce oxidants. There was also a strong correlation between the antioxidant activities and polyphenolic content suggesting the observed antioxidant activities were contributed mainly by the polyphenolics in the plants.
  7. Belqes Abdullah, A. T., Yvonne, T. G. B., Ahmad, S. H., Abdul Aziz, A. S. I., Aida, H. G. R.
    MyJurnal
    Introduction: Iontophoresis of vasoactive substances such as acetylcholine (ACh) and sodium nitroprusside (SNP) combined with Laser Doppler fluximetry (LDF) is a non-invasive tool used to determine microvascular endothelial function. This study aims to test the effect of sodium chloride on
    non-specific vasodilatation when used as a vehicle in the process of iontophoresis. This study also aims to define the number of current pulses needed to get the maximum effect during iontophoresis with ACh and SNP using low current strength. Methods: The experiment was conducted in five healthy females. Baseline skin perfusion was taken before administration of seven current pulses. Current strength of 0.007 mA and current density of 0.01 mA/cm2 were used. Acetylcholine was used to assess endothelial dependent vasodilatation, while SNP was used to assess endothelial independent vasodilatation. The mean skin perfusion (AU) responses to the iontophoresis of ACh at the anodal and SNP at the cathode leads were recorded. Sodium chloride (0.9%) was used as a vehicle to obtain concentration of 1% for both ACh and SNP. Iontophoresis of pure vehicle (NaCl) was conducted on a separate day to observe the effect of vehicle only on the iontophoresis process at both anode and cathode. Results: Iontophoresis of NaCl showed no significant increase in perfusion compared to baseline at both anode and cathode. Significant increases in skin perfusion were observed with SNP and ACh; a plateau of ACh was reached from the 3rd pulse onwards; while the plateau of SNP was reached from the 4th pulse onwards. Conclusion: NaCl could be used as a vehicle for Ach and SNP during iontophoresis as it did not cause non-specific vasodilatation. Using five current pulses are adequate for iontophoresis of ACh and SNP to assess microvascular endothelial function.
  8. Makhadmeh GN, Abdul Aziz A
    Artif Cells Nanomed Biotechnol, 2018;46(sup3):S1043-S1046.
    PMID: 30449196 DOI: 10.1080/21691401.2018.1528982
    BACKGROUND: Achieved Silica Nanoparticles (SiNPs) to encapsulate the photosensitizer [Protoporphyrin IX (PpIX)] in photodynamic therapy (PDT) application was reported in this research.

    MATERIALS AND METHODS: Cytotoxicity for five different concentrations of encapsulated and naked PpIX was measured. Optimum concentration and optimum exposure time of encapsulated and naked PpIX that needed to destroy the cells (Osteosarcoma cells) was measured.

    RESULTS: The results showed that the encapsulated PpIX has more efficacy compared to the naked PpIX and the applicability of the encapsulated PpIX-SiNPs was proved on osteosarcoma cells.

    CONCLUSION: The results established the important in-vitro photodynamic effectiveness of PpIX-SiNP, which may open a new application for PpIX in its clinical and in-vitro studies.

  9. Sajjadi B, Abdul Aziz AR, Ibrahim S
    Ultrason Sonochem, 2015 Jan;22:463-73.
    PMID: 24981808 DOI: 10.1016/j.ultsonch.2014.06.004
    The influence of sonoluminescence transesterification on biodiesel physicochemical properties was investigated and the results were compared to those of traditional mechanical stirring. This study was conducted to identify the mechanistic features of ultrasonication by coupling statistical analysis of the experiments into the simulation of cavitation bubble. Different combinations of operational variables were employed for alkali-catalysis transesterification of palm oil. The experimental results showed that transesterification with ultrasound irradiation could change the biodiesel density by about 0.3kg/m(3); the viscosity by 0.12mm(2)/s; the pour point by about 1-2°C and the flash point by 5°C compared to the traditional method. Furthermore, 93.84% of yield with alcohol to oil molar ratio of 6:1 could be achieved through ultrasound assisted transesterification within only 20min. However, only 89.09% of reaction yield was obtained by traditional macro mixing/heating under the same condition. Based on the simulated oscillation velocity value, the cavitation phenomenon significantly contributed to generation of fine micro emulsion and was able to overcome mass transfer restriction. It was found that the sonoluminescence bubbles reached the temperature of 758-713K, pressure of 235.5-159.55bar, oscillation velocity of 3.5-6.5cm/s, and equilibrium radius of 17.9-13.7 times greater than its initial size under the ambient temperature of 50-64°C at the moment of collapse. This showed that the sonoluminescence bubbles were in the condition in which the decomposition phenomena were activated and the reaction rate was accelerated together with a change in the biodiesel properties.
  10. Abioye OP, Agamuthu P, Abdul Aziz AR
    Biotechnol Res Int, 2012;2012:587041.
    PMID: 22919502 DOI: 10.1155/2012/587041
    Soil and surface water contamination by used lubricating oil is a common occurrence in most developing countries. This has been shown to have harmful effects on the environment and human beings at large. Bioremediation can be an alternative green technology for remediation of such hydrocarbon-contaminated soil. Bioremediation of soil contaminated with 5% and 15% (w/w) used lubricating oil and amended with 10% brewery spent grain (BSG), banana skin (BS), and spent mushroom compost (SMC) was studied for a period of 84 days, under laboratory condition. At the end of 84 days, the highest percentage of oil biodegradation (92%) was recorded in soil contaminated with 5% used lubricating oil and amended with BSG, while only 55% of oil biodegradation was recorded in soil contaminated with 15% used lubricating oil and amended with BSG. Results of first-order kinetic model to determine the rate of biodegradation of used lubricating oil revealed that soil amended with BSG recorded the highest rate of oil biodegradation (0.4361 day(-1)) in 5% oil pollution, while BS amended soil recorded the highest rate of oil biodegradation (0.0556 day(-1)) in 15% oil pollution. The results of this study demonstrated the potential of BSG as a good substrate for enhanced remediation of hydrocarbon contaminated soil at low pollution concentration.
  11. Abioye OP, Agamuthu P, Abdul Aziz AR
    Biodegradation, 2012 Apr;23(2):277-86.
    PMID: 21870160 DOI: 10.1007/s10532-011-9506-9
    Soil contamination by hydrocarbons, especially by used lubricating oil, is a growing problem in developing countries, which poses a serious threat to the environment. Phytoremediation of these contaminated soils offers environmental friendly and a cost effective method for their remediation. Hibiscus cannabinus was studied for the remediation of soil contaminated with 2.5 and 1% used lubricating oil and treated with organic wastes [banana skin (BS), brewery spent grain (BSG) and spent mushroom compost (SMC)] for a period of 90 days under natural conditions. Loss of 86.4 and 91.8% used lubricating oil was recorded in soil contaminated with 2.5 and 1% oil and treated with organic wastes respectively at the end of 90 days. However, 52.5 and 58.9% oil loss was recorded in unamended soil contaminated with 2.5 and 1% oil, respectively. The plant did not accumulate hydrocarbon from the soil but shows appreciable accumulation of Fe and Zn in the root and stem of H. cannabinus at the end of the experiment. The first order kinetic rate of uptake of Fe and Zn in H. cannabinus was higher in organic wastes amendment treatments compared to the unamended treatments, which are extremely low. The results of this study suggest that H. cannabinus has a high potential for remediation of hydrocarbon and heavy metal contaminated soil.
  12. Salmuna ZN, Hashim S, Hasan H, Harun A, Abdul Rahman Z, Ismail N, et al.
    IIUM Medical Journal Malaysia, 2019;18(3):144-152.
    MyJurnal
    Influenza-like illnesses (ILI) were defined as a triad of cough, sore throat and fever. The aim of this study is to determine the changes in knowledge, perceptions and practices towards preventive measures of succumbing to ILI before and after hajj among Malaysian hajj pilgrims.Methodology: An open-labeled randomized control trial study performed on five hundred Malaysian hajj pilgrims in the year 2013. After validated pre-hajj questionnaires completed, 250 subjects were given health education, benzalkonium-based handrub and demonstration of the handrub usage together with pamphlets and labelled as an intervention group. Another 250 subjects from another flight batch were given the same questionnaires without health education with unmedicated hand lotion as a control group. The knowledge, perception, practices and compliances to the handrub practice in both groups were compared with the pre-hajj results. Results: No significant difference between pre and post hajj knowledge and practice among hajj pilgrims in intervention group. Pre hajj perception score [ M (IQR) = 30 (5.00), Z= -2.441, p < 0.05 ] is much higher compared to post hajj perception [ M (IQR) = 29 (6.00), Z = -2.441, p < O.O5 ]. No significant difference between pre and post hajj knowledge, perception and practices among hajj pilgrims in control group. Hand hygiene compliance was not improved with provision of health education and free handrub supply. Conclusion: No significant changes in knowledge, perceptions and practices of Malaysian hajj pilgrims pre and post-hajj in both groups. Provision of handrub did not improved hajj pilgrims compliance.
  13. Chew KS, Kueh YC, Abdul Aziz A
    BMC Med Educ, 2017 Mar 21;17(1):58.
    PMID: 28320367 DOI: 10.1186/s12909-017-0897-0
    BACKGROUND: Despite their importance on diagnostic accuracy, there is a paucity of literature on questionnaire tools to assess clinicians' awareness toward cognitive errors. A validation study was conducted to develop a questionnaire tool to evaluate the Clinician's Awareness Towards Cognitive Errors (CATChES) in clinical decision making.

    METHODS: This questionnaire is divided into two parts. Part A is to evaluate the clinicians' awareness towards cognitive errors in clinical decision making while Part B is to evaluate their perception towards specific cognitive errors. Content validation for both parts was first determined followed by construct validation for Part A. Construct validation for Part B was not determined as the responses were set in a dichotomous format.

    RESULTS: For content validation, all items in both Part A and Part B were rated as "excellent" in terms of their relevance in clinical settings. For construct validation using exploratory factor analysis (EFA) for Part A, a two-factor model with total variance extraction of 60% was determined. Two items were deleted. Then, the EFA was repeated showing that all factor loadings are above the cut-off value of >0.5. The Cronbach's alpha for both factors are above 0.6.

    CONCLUSION: The CATChES questionnaire tool is a valid questionnaire tool aimed to evaluate the awareness among clinicians toward cognitive errors in clinical decision making.

  14. Abrahim NN, Kanthimathi MS, Abdul-Aziz A
    BMC Complement Altern Med, 2012 Nov 15;12:220.
    PMID: 23153283 DOI: 10.1186/1472-6882-12-220
    BACKGROUND: Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7.

    METHODS: The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane) and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase) assays in MCF-7 cells.

    RESULTS: Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml). Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase.

    CONCLUSIONS: Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide dismutase in the treated cells could alter the antioxidant defense system, potentially contributing towards the anti-proliferative effect. There is great potential for the ethyl acetate extract of P. betle leaf as a source of natural antioxidants and to be developed as therapeutics in cancer treatment.

  15. Letchumanan K, Abdullah NH, Abdul-Aziz A
    Prep Biochem Biotechnol, 2024 Jul;54(6):749-763.
    PMID: 37990367 DOI: 10.1080/10826068.2023.2282529
    Dynamic maceration facilitates diffusion in solid-liquid extraction through controlling temperature and providing agitation. However, equipment design for dynamic maceration in previous investigations resulted in inadequate homogeneity of temperature and solid dispersion. A laboratory scale extractor was designed to aid the heat and mass transfer process while preventing solvent vaporization when performing dynamic maceration in a controlled environment. This study aimed to evaluate the efficiency of dynamic maceration using the laboratory scale extractor compared to a shaker incubator to extract triterpenoid saponins from Azadirachta excelsa leaves. The dynamic maceration of A. excelsa leaves was optimized using a Face-centered central composite design (FCCCD) with response surface methodology (RSM). Independent variables analyzed include ethanol-to-chloroform ratio, extraction temperature, extraction time, and sample-to-solvent ratio, while responses include yield of extract and triterpenoid saponins content (TSC). Optimum conditions were ethanol-to-chloroform ratio of 90:10, extraction temperature of 45 °C, extraction time of 60 minutes, and sample-to-solvent ratio of 1:50 g/ml. There was a significant percentage of increase in yield of extract and TSC by 41.1% and 13.3%, respectively, for the laboratory scale extractor compared to the shaker incubator. This study showed the importance of equipment design in enhancing triterpenoid saponins extraction through elevating the efficiency of the dynamic maceration process.
  16. Makhadmeh GN, Abdul Aziz A, Abdul Razak K
    Artif Cells Nanomed Biotechnol, 2016 May;44(3):1018-22.
    PMID: 25707443 DOI: 10.3109/21691401.2015.1008511
    This study analyzed the physical effects of methylene blue (MB) encapsulated within silica nanoparticles (SiNPs) in photodynamic therapy.
  17. Hasan DB, Abdul Aziz AR, Daud WM
    Environ Technol, 2012 Jun;33(10-12):1111-21.
    PMID: 22856280
    The mineralisation of remazol black B (RBB) was studied at concentrations ranging from 20-1000 mgL(-1). The work was aimed at investigating the Fenton-like peroxidation of RBB at a concentration typically obtained in Batik cottage industries. Other response parameters were degradation and colour removal efficiencies. The parameters that were measured included total organic carbon (TOC), chemical oxygen demand (COD) as well as absorbance for mineralisation, degradation and colour. To optimise the process, the interaction effects of several controlling variables on the treatment process were examined using dispersion matrix-optimal design and response surface analysis. Four specific variables: initial dye concentration (Dye)o; the molar ratio of oxidant to dye organic strength (H2O2):(COD); the mass ratio of the oxidant to the catalyst (H2O2):(Fe3+) and reaction time (t(r)), were observed. Three reduced empirical models, one for each response, were developed for describing the treatment process. For 20, 510 and 1000 mgL(-1), the optimum %TOC reduction and oxidation times were 44% for 95 min, 52% for 52.5 min and 68% for 10 min corresponding to 67, 81 and 75% COD reduction, respectively. The optimum COD reduction and oxidation times were 89% for 95 min, 91% for 10 min and 84% for 95 min for concentrations of 20, 510 and 1000 mg L(-1), respectively. For all concentrations, total colour removal was achieved. A comparison of the results obtained in this study with literature values for traditional Fenton, photo-Fenton and photo-Fenton-like oxidation indicated that the TOC reduction obtained using the Fenton-like process was satisfactory.
  18. Ridhuan NS, Razak KA, Lockman Z, Abdul Aziz A
    PLoS One, 2012;7(11):e50405.
    PMID: 23189199 DOI: 10.1371/journal.pone.0050405
    In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ZnO seeds was 400°C. The nanorod dimensions depended on the hydrothermal reaction parameters. The optimum hydrothermal reaction parameters to produce blunt tip-like nanorods (770 nm long and 80 nm in top diameter) were 0.1 M zinc nitrate, pH 7, and 4 h of growth duration. Phase analysis studies showed that all ZnO nanorods exhibited a strong (002) peak. Thus, the ZnO nanorods grew in a c-axis preferred orientation. A strong ultraviolet (UV) emission peak was observed for ZnO nanorods grown under optimized parameters with a low, deep-level emission peak, which indicated high optical property and crystallinity of the nanorods. The produced ZnO nanorods were also tested for their UV-sensing properties. All samples responded to UV light but with different sensing characteristics. Such different responses could be attributed to the high surface-to-volume ratio of the nanorods that correlated with the final ZnO nanorods morphology formed at different synthesis parameters. The sample grown using optimum synthesis parameters showed the highest responsivity of 0.024 A/W for UV light at 375 nm under a 3 V bias.
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