Displaying publications 1 - 20 of 68 in total

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  1. Ebrahimiasl S, Zakaria A
    Sensors (Basel), 2014;14(2):2549-60.
    PMID: 24509767 DOI: 10.3390/s140202549
    A nanocrystalline SnO2 thin film was synthesized by a chemical bath method. The parameters affecting the energy band gap and surface morphology of the deposited SnO2 thin film were optimized using a semi-empirical method. Four parameters, including deposition time, pH, bath temperature and tin chloride (SnCl2·2H2O) concentration were optimized by a factorial method. The factorial used a Taguchi OA (TOA) design method to estimate certain interactions and obtain the actual responses. Statistical evidences in analysis of variance including high F-value (4,112.2 and 20.27), very low P-value (<0.012 and 0.0478), non-significant lack of fit, the determination coefficient (R2 equal to 0.978 and 0.977) and the adequate precision (170.96 and 12.57) validated the suggested model. The optima of the suggested model were verified in the laboratory and results were quite close to the predicted values, indicating that the model successfully simulated the optimum conditions of SnO2 thin film synthesis.
  2. Velo P, Zakaria A
    J Med Imaging Radiat Sci, 2017 Mar;48(1):39-42.
    PMID: 31047208 DOI: 10.1016/j.jmir.2016.10.010
    It is important to monitor the spatial resolution of a gamma camera on a weekly basis to acquire medical images with accurate quantitative information. A simple and fast computer program with a graphical user interface to analyze spatial resolution was successfully developed using MATLAB. The results were compared with those obtained from the standard processing system available in our gamma camera. The spatial resolution calculated using MATLAB was 1.24% lower than using the standard processing system. The developed program is cost effective, faster, and provides an easy platform for the physicists and technologists to analyze the spatial resolution based on the image of the line source.
  3. Velo P, Zakaria A
    J Med Imaging Radiat Sci, 2015 Sep;46(3S):S31-S36.
    PMID: 31052105 DOI: 10.1016/j.jmir.2015.06.002
    INTRODUCTION: The aim of this study was to assess the influence of background activity on the accuracy of volume estimation of target objects using an iterative thresholding method.

    METHODS: Single-photon-emission computed tomography studies were carried out for plastic bottles of various sizes as target objects containing Technetium-99m placed in a cylindrical water phantom. The phantoms were created to have varying ratios of target activity concentration to background activity concentration (T/B) ranging from 4.00 to 1.25. From the single-photon-emission computed tomography slices, the volume of the target object was estimated using an iterative thresholding method. A unique threshold that estimated the volume of the target object was determined and declared as ideal threshold for each level of background activity. Simple linear regression analysis was carried out to explore the relationship between the actual volume and estimated volume.

    RESULTS: The analysis shows a statistically significant linear relationship (P < .01) between actual volume and estimated volume. For all ratios of target activity concentration to background activity concentration studied, the relative errors in estimated volumes of target objects are within ±7%. Thresholds that estimated volume of target objects vary depending on the level of background activity.

    CONCLUSIONS: It is clearly demonstrated that background activity highly influenced the volume estimation. Therefore, background activity of the target object needs to be considered when selecting the ideal thresholds to obtain accurate volume estimation of target objects.

  4. Zakaria A, Ho YB
    Regul Toxicol Pharmacol, 2015 Oct;73(1):191-5.
    PMID: 26190304 DOI: 10.1016/j.yrtph.2015.07.005
    This study aimed to determine the heavy metals (lead, cadmium, and chromium) concentration in lipsticks of different price categories sold in the Malaysian market and evaluate the potential health risks due to daily ingestion of heavy metals in lipsticks. A total of 374 questionnaires were distributed to the female staff in a public university in Malaysia in order to obtain information such as brand and price of the lipsticks, body weight, and frequency and duration of wearing lipstick. This information was important for the calculation of hazard quotient (HQ) in health risk assessment. The samples were extracted using a microwave digester and analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The concentrations of lead, cadmium, and chromium in lipsticks ranged from 0.77 to 15.44 mg kg(-1), 0.06-0.33 mg kg(-1), and 0.48-2.50 mg kg(-1), respectively. There was a significant difference of lead content in the lipsticks of different price categories. There was no significant non-carcinogenic health risk due to the exposure of these heavy metals through lipstick consumption for the prolonged exposure of 35 years (HQ < 1).
  5. Aznan, A.A., Rukunudin, I.H., Shakaff, A.Y.M.,, Ruslan, R.,, Zakaria, A., Saad, F.S.A.
    MyJurnal
    Seed purity is a crucial seed quality parameter in the Malaysian rice seed standard. The use of
    high quality cultivated rice seed, free of any foreign seeds, is the prerequisite to sustaining high
    yield in rice production. The presence of foreign seeds such as weedy rice in the cultivated rice
    seeds used by the farmers can adversely affect growth and yield as it competes for space and
    nutrients with the cultivated rice varieties in the field. Being the most dominant and competitive
    element compared to the cultivated rice seeds, the Malaysian seed standard prescribed that the
    maximum allowable of weed seeds in a 20-kilogram certified rice seed bag produced by local
    rice seed processors is 10 weed seeds per kilogram. The current cleaning processes that rely
    mostly on the difference in physical traits do not guarantee effective separation of weedy rice
    seeds from the lots. Seed bags found to contain more than 10 weed seeds upon inspection by
    the enforcing agency will not be approved for distribution to farmers. The paper describes a
    study carried out to explore the use of machine vision approach to separate weedy rice seed
    from cultivated rice seeds as a potential cleaning technique for the rice seed industry. The mean
    classification accuracies levels of the extracted morphological feature model were achieved at
    95.8% and 96.0% for training and testing data sets respectively.
  6. Zakaria AF, Tsuji M
    Malays Orthop J, 2019 Nov;13(3):85-87.
    PMID: 31890118 DOI: 10.5704/MOJ.1911.016
    Intracranial subdural hematoma following lumbar surgery is a devastating but rare complication. It has been implicated due to intracranial hypotension secondary to persistent cerebrospinal fluid leakage. The resultant drop in intracranial pressure presumably causes traction and tearing of venous structures. Patients typically present with postural headaches. However, other symptoms of subdural hematoma, intracranial hypotension and cerebrospinal fluid leak must also be cautioned.
  7. Noroozi M, Radiman S, Zakaria A, Soltaninejad S
    Nanoscale Res Lett, 2014;9(1):645.
    PMID: 25489293 DOI: 10.1186/1556-276X-9-645
    Silver nanoparticles were successfully prepared in two different solvents using a microwave heating technique, with various irradiation times. The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP). The optical properties, thermal properties, and morphology of the synthesized silver particles were characterized using ultraviolet-visible spectroscopy, photopyroelectric technique, and transmission electron microscopy. It was found that for the both solvents, the effect of microwave irradiation was mainly on the particles distribution, rather than the size, which enabled to make stable and homogeneous silver nanofluids. The individual spherical nanostructure of self-assembled nanoparticles has been formed during microwave irradiation. Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water. A photopyroelectric technique was carried out to measure thermal diffusivity of the samples. The precision and accuracy of this technique was established by comparing the measured thermal diffusivity of the distilled water and ethylene glycol with values reported in the literature. The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.
  8. Rizwan Z, Zakaria A, Ghazali MS
    Int J Mol Sci, 2011;12(3):1625-32.
    PMID: 21673911 DOI: 10.3390/ijms12031625
    Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.
  9. Muzaffar TST, Imran Y, Iskandar MA, Zakaria A
    Med J Malaysia, 2005 Jul;60 Suppl C:26-9.
    PMID: 16381279
    Femoral interlocking nailing requires fluoroscopic assistance for insertion of the nail and distal screws. In this study, scattered radiation to the eye and hand of the operating surgeon was measured during the procedure. Thermo-luminescent dosimeter (TLD) was used to quantify the dose received by the surgeon. The mean radiation exposure time during the procedure was 3.89 minutes. The mean scattered radiation doses to the hand and eye were 0.27 mSv and 0.09 mSv per procedure respectively. These very low doses have made a surgeon very unlikely to receive more than the recommended annual dose limit set by the National Council on Radiological Protection.
  10. Biswal BM, Zakaria A, Baba AA, Ja'afar R
    Med J Malaysia, 2004 Mar;59(1):78-83.
    PMID: 15535340
    We conducted a questionnaire survey among 261 year-4 and year-5 medical students containing 27 questions related to cancer, radiotherapy, general oncology and palliative care to assess their knowledge, understanding, and exposure to oncology and palliative care in our medical school. Out of 261 students, 139 students returned their questionnaire for analysis. Twenty nine percent (29%) of the students had rarely visited the Radiotherapy and Oncology unit. There were profound deficiencies in the basic knowledge of cancer (46%), principles of radiotherapy treatment (59%), palliative care (64%), and cancer prevention (48%). They reported no specific teaching about early detection of common malignancies and cancer prevention. The main input of instruction about cancer came from surgery (46%) and pathology (28%) teachings. This study revealed that there is deficiency in cancer education in the undergraduate teaching program in our institution.
  11. Biswal BM, Zakaria A, Ahmad NM
    Support Care Cancer, 2003 Apr;11(4):242-8.
    PMID: 12673463
    BACKGROUND: The aim of this study was to evaluate the effect of pure natural honey on radiation-induced mucositis.

    PATIENTS AND METHODS: Forty patients diagnosed with head and neck cancer requiring radiation to the oropharyngeal mucosal area were divided in to two groups to receive either radiation alone or radiation plus topical application of pure natural honey. Patients were treated using a 6-MV linear accelerator at a dose rate of 2 Gy per day five times a week up to a dose of 60-70 Gy. In the study arm, patients were advised to take 20 ml of pure honey 15 min before, 15 min after and 6 h post-radiation therapy. Patients were evaluated every week for the development of radiation mucositis using the Radiation Therapy Oncology Group (RTOG) grading system.

    MAIN RESULTS: There was significant reduction in the symptomatic grade 3/4 mucositis among honey-treated patients compared to controls; i.e. 20% versus 75% ( p 0.00058). The compliance of honey-treated group of patients was better than controls. Fifty-five percent of patients treated with topical honey showed no change or a positive gain in body weight compared to 25% in the control arm ( p 0.053), the majority of whom lost weight.

    CONCLUSIONS: Topical application of natural honey is a simple and cost-effective treatment in radiation mucositis, which warrants further multi-centre randomised trials to validate our finding.

  12. Biswal BM, Ruzman N, Ahmad NM, Zakaria A
    Malays J Med Sci, 2000 Jan;7(1):54-9.
    PMID: 22844216 MyJurnal
    Short course hypo-fractionated radiotherapy is a standard regime for the palliation of stage IV head and neck cancers. However few patients respond favorably and require further radiotherapy in curative intent. We have used split-course radiotherapy technique to find out this conversion rate from palliative to curative intent. This was a prospective study conducted from November 1998 to October 1999; twenty-six (26) patients with stage IV head & neck cancers were treated with a hypofractionated regime of radiotherapy. A tumor dose of 30 Gy in 10 fractions [time dose fraction (TDF) 62] over 2 weeks was delivered using a 6 MV linear accelerator. A conventional 2 field or 3 field technique was used. Patients were assessed for the regression of tumor on fifth day, tenth day of radiotherapy and 4 weeks after the completion of radiotherapy. Patients showing complete response and good partial response were allowed to receive further radiotherapy of 30 Gy in 15 fractions [TDF 49]. There were 21 males and 5 females in the study with a median age of 44 years (range 19-77 years). All patients completed the initial regime. Complete responses were observed among 14 patients (54%); partial response in 6 patients (23%), and no response was seen among 6 patients (23%). Sixteen patients (61%) were suitable for radical radiotherapy after phase-I course of the above schedule. Seventeen patients (65%) showed an improvement in the general well being with a better quality of life. One year actuarial survival was (76%), with a median survival time of 12 months. Split-course technique is a useful radiotherapy treatment in stage IV head and neck cancers to distinguish between the subset of patients who would require curative treatment and who would not.
  13. Rozali, A., Zakaria, A., Sherina, M.S., Muhd Amin, M., Mohd Ghazalli, M.T., Muhamad Ello, M.S., et al.
    MyJurnal
    Military personnel who are deployed for peace-keeping missions are exposed to many hazards, including infectious diseases. One of the most common and fatal infectious disease is Malaria. Although well controlled in Malaysia, this deadly disease is still widely endemic in many other countries especially Africa. We would like to report the case of a military personnel who was infected with Malaria during a peace-keeping mission in Sudan and subsequently died after returning home. We hope that by reporting this case in depth, strategic actions can be taken to avoid similar unfortunate events in future.
  14. Noroozi M, Mohammadi B, Radiman S, Zakaria A
    ScientificWorldJournal, 2018;2018:9458952.
    PMID: 29686589 DOI: 10.1155/2018/9458952
    The application of optical-fiber thermal wave cavity (OF-TWC) technique was investigated to measure the thermal diffusivity of Ag nanofluids. The thermal diffusivity was obtained by measuring the thermal wavelength of sample in a cavity scan mode. The spherical Ag nanoparticles samples were prepared at various sizes using the microwave method. Applying the thermal wavelength measurement in a flexible OF-TWC technique requires only two experimental data sets. It can be used to estimate thermal diffusivity of a small amount of liquid samples (0.3 ml) in a brief period. UV-Vis spectroscopy and transmission electron microscopy were used to measure the characterization of the Ag nanoparticles. The thermal diffusivity of distilled water, glycerol, and two different types of cooking oil was measured and has an excellent agreement with the reported results in the literature (difference of only 0.3%-2.4%). The nanofluids showed that the highest value of thermal diffusivity was achieved for smaller sized nanoparticles. The results of this method confirmed that the thermal wavelength measurement method using the OF-TWC technique had potential as a tool to measure the thermal diffusivity of nanofluids with different variables such as the size, shape, and concentration of the nanoparticles.
  15. Zakaria A, Jais MR, Ishak R
    J Nat Sci Biol Med, 2018 Jan-Jun;9(1):23-26.
    PMID: 29456388 DOI: 10.4103/jnsbm.JNSBM_131_17
    Background: This study investigates the analgesic properties of the aqueous extracts ofNigella sativa and Eucheuma cottoniiin mice. The analgesic properties of both extracts were evaluated in an experimental model of acetic acid-induced writhing test.

    Materials and Methods: The mice were divided into four different groups and received the test extracts and the standard drug (aspirin) for 14 days via force-feeding. On day 15, the mice were injected with 5% acetic acid, and the number of abdominal constriction and elongation of hind limb (writhes) were counted for 20 min.

    Results: The numbers of writhes were counted starting after 5 min of the acetic acid injection. TheN. sativaextracts significantly reduced the number of writhes as compared to the control group. Both of the extracts revealed a comparable result as referred to the aspirin effects in the mice.

    Conclusions: These findings indicate thatN. sativaandE. cottoniimay possess protective active constituent that is effective in reducing the sensation of pain in mice.
  16. Kamarudin K, Mamduh SM, Shakaff AY, Zakaria A
    Sensors (Basel), 2014;14(12):23365-87.
    PMID: 25490595 DOI: 10.3390/s141223365
    This paper presents a performance analysis of two open-source, laser scanner-based Simultaneous Localization and Mapping (SLAM) techniques (i.e., Gmapping and Hector SLAM) using a Microsoft Kinect to replace the laser sensor. Furthermore, the paper proposes a new system integration approach whereby a Linux virtual machine is used to run the open source SLAM algorithms. The experiments were conducted in two different environments; a small room with no features and a typical office corridor with desks and chairs. Using the data logged from real-time experiments, each SLAM technique was simulated and tested with different parameter settings. The results show that the system is able to achieve real time SLAM operation. The system implementation offers a simple and reliable way to compare the performance of Windows-based SLAM algorithm with the algorithms typically implemented in a Robot Operating System (ROS). The results also indicate that certain modifications to the default laser scanner-based parameters are able to improve the map accuracy. However, the limited field of view and range of Kinect's depth sensor often causes the map to be inaccurate, especially in featureless areas, therefore the Kinect sensor is not a direct replacement for a laser scanner, but rather offers a feasible alternative for 2D SLAM tasks.
  17. Ebrahimiasl S, Zakaria A, Kassim A, Basri SN
    Int J Nanomedicine, 2015;10:217-27.
    PMID: 25565815 DOI: 10.2147/IJN.S69740
    An antibacterial and conductive bionanocomposite (BNC) film consisting of polypyrrole (Ppy), zinc oxide (ZnO) nanoparticles (NPs), and chitosan (CS) was electrochemically synthesized on indium tin oxide (ITO) glass substrate by electrooxidation of 0.1 M pyrrole in aqueous solution containing appropriate amounts of ZnO NPs uniformly dispersed in CS. This method enables the room temperature electrosynthesis of BNC film consisting of ZnO NPs incorporated within the growing Ppy/CS composite. The morphology of Ppy/ZnO/CS BNC was characterized by scanning electron microscopy. ITO-Ppy/CS and ITO-Ppy/ZnO/CS bioelectrodes were characterized using the Fourier transform infrared technique, X-ray diffraction, and thermogravimetric analysis. The electrical conductivity of nanocomposites was investigated by a four-probe method. The prepared nanocomposites were analyzed for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl assay. The results demonstrated that the antioxidant activity of nanocomposites increased remarkably by addition of ZnO NPs. The electrical conductivity of films showed a sudden decrease for lower weight ratios of ZnO NPs (5 wt%), while it was increased gradually for higher ratios (10, 15, and 20 wt%). The nanocomposites were analyzed for antibacterial activity against Gram-positive and Gram-negative bacteria. The results indicated that the synthesized BNC is effective against all of the studied bacteria, and its effectiveness is higher for Pseudomonas aeruginosa. The thermal stability and physical properties of BNC films were increased by an increase in the weight ratio of ZnO NPs, promising novel applications for the electrically conductive polysaccharide-based nanocomposites, particularly those that may exploit the antimicrobial nature of Ppy/ZnO/CS BNCs.
  18. Dorraj M, Zakaria A, Abdollahi Y, Hashim M, Moosavi S
    ScientificWorldJournal, 2014;2014:741034.
    PMID: 25243225 DOI: 10.1155/2014/741034
    In ZnO-based low voltage varistor, the two essential features of microstructure determining its nonlinear response are the formation Bi-enriched active grain boundaries as well as a controlled ZnO grain size by secondary spinel-type phases. Besides, the microstructure and phase composition are strongly affected by the dopant concentration during sintering process. In this study, the optimal dopant levels of Bi2O3, TiO2, and Sb2O3 to achieve maximized nonlinear electrical property (alpha) were quantified by the response surface methodology (RSM). RSM was also used to understand the significance and interaction of the factors affecting the response. Variables were determined as the molar ratio of Bi2O3, TiO2, and Sb2O3. The alpha was chosen as response in the study. The 5-level-3-factor central composite design, with 20 runs, was used to conduct the experiments by ball milling method. A quadratic model was established as a functional relationship between three independent variables and alpha. According to the results, the optimum values of Bi2O3, TiO2, and Sb2O3 were obtained 0.52, 0.50, and 0.30, respectively. Under optimal conditions the predicted alpha (9.47) was calculated using optimal coded values from the model and the theoretical value is in good agreement with the value (9.43) obtained by confirmation experiment.
  19. Zakaria NZ, Masnan MJ, Zakaria A, Shakaff AY
    Sensors (Basel), 2014;14(7):12233-55.
    PMID: 25010697 DOI: 10.3390/s140712233
    Herbal-based products are becoming a widespread production trend among manufacturers for the domestic and international markets. As the production increases to meet the market demand, it is very crucial for the manufacturer to ensure that their products have met specific criteria and fulfil the intended quality determined by the quality controller. One famous herbal-based product is herbal tea. This paper investigates bio-inspired flavour assessments in a data fusion framework involving an e-nose and e-tongue. The objectives are to attain good classification of different types and brands of herbal tea, classification of different flavour masking effects and finally classification of different concentrations of herbal tea. Two data fusion levels were employed in this research, low level data fusion and intermediate level data fusion. Four classification approaches; LDA, SVM, KNN and PNN were examined in search of the best classifier to achieve the research objectives. In order to evaluate the classifiers' performance, an error estimator based on k-fold cross validation and leave-one-out were applied. Classification based on GC-MS TIC data was also included as a comparison to the classification performance using fusion approaches. Generally, KNN outperformed the other classification techniques for the three flavour assessments in the low level data fusion and intermediate level data fusion. However, the classification results based on GC-MS TIC data are varied.
  20. Noroozi M, Zakaria A, Moksin MM, Wahab ZA
    Int J Mol Sci, 2012;13(8):10350-8.
    PMID: 22949865 DOI: 10.3390/ijms130810350
    The thermal effusivity of Al(2)O(3) and CuO nanofluids in different base fluids, i.e., deionized water, ethylene glycol and olive oil were investigated. The nanofluids, nanoparticles dispersed in base fluids; were prepared by mixing Al(2)O(3), CuO nanopowder and the base fluids using sonication with high-powered pulses to ensure a good uniform dispersion of nanoparticles in the base fluids. The morphology of the particles in the base fluids was investigated by transmission electron microscopy (TEM). In this study, a phase frequency scan of the front pyroelectric configuration technique, with a thermally thick PVDF pyroelectric sensor and sample, was used to measure the thermal effusivity of the prepared nanofluids. The experimental results of the thermal effusivity of the studied solvents (deionized water, ethylene glycol and olive oil) showed good agreement with literature values, and were reduced in the presence of nanoparticles. The thermal effusivity of the nanofluid was found to be particularly sensitive to its base fluid and the type of nanoparticles.
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