Displaying all 13 publications

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  1. Mustafa F, Hashim AM
    Sensors (Basel), 2014;14(2):3493-505.
    PMID: 24561400 DOI: 10.3390/s140203493
    We report the RF-to-DC characteristics of the integrated AlGaAs/GaAs Schottky diode and antenna under the direct injection and irradiation condition. The conversion efficiency up to 80% under direct injection of 1 GHz signal to the diode was achieved. It was found that the reduction of series resistance and parallel connection of diode and load tend to lead to the improvement of RF-to-DC conversion efficiency. Under direct irradiation from antenna-to-antenna method, the output voltage of 35 mV was still obtainable for the distance of 8 cm between both antennas in spite of large mismatch in the resonant frequency between the diode and the connected antenna. Higher output voltage in volt range is expected to be achievable for the well-matching condition. The proposed on-chip AlGaAs/GaAs HEMT Schottky diode and antenna seems to be a promising candidate to be used for application in proximity communication system as a wireless low power source as well as a highly sensitive RF detector.
  2. Avicor SW, Wajidi MF, Jaal Z, Yahaya ZS
    Acta Biochim. Pol., 2016;63(2):243-6.
    PMID: 27059016 DOI: 10.18388/abp.2014_909
    Septins belong to GTPases that are involved in vital cellular activities, including cytokinesis. Although present in many organisms, they are yet to be isolated from Aedes albopictus. This study reports for the first time on a serendipitous isolation of a partial septin sequence from Ae. albopictus and its developmental expression profile. The Ae. albopictus partial septin sequence contains 591 nucleotides encoding 197 amino acids. It shares homology with several insect septin genes and has a close phylogenetic relationship with Aedes aegypti and Culex quinquefasciatus septins. The Ae. albopictus septin fragment was differentially expressed in the mosquito's developmental stages, with an increased expression in the adults.
  3. El-Garj FMA, Wajidi MFF, Avicor SW
    Asian Pac J Trop Med, 2016 10;9(10):973-978.
    PMID: 27794391 DOI: 10.1016/j.apjtm.2016.07.024
    OBJECTIVE: To clone cytochrome P450 from Aedes aegypti (Ae. aegypti) and determine the characteristics using bioinformatics tools.

    METHODS: Cytochrome P450 of Ae. aegypti was amplified using polymerase chain reaction, cloned and sequenced. Evolutionary relationship of the sequence was inferred and bioinformatics tools were used to predict subcellular localisation, signal peptide, transmembrane helix, phosphorylation, O-glycosylation, secondary and tertiary structures of the deduced protein.

    RESULTS: Polymerase chain reaction rather amplified a cytochrome P450 pseudogene which was named CYP4H44P (GenBank accession number KF779932). The pseudogene has 1537 nucleotides and an open reading frame of 335 amino acids containing cytochrome P450 motifs except the WxxxR motif. It is highly homologous to CYP4H28 and CYP4H28v2. Phylogenetic analysis and evolutionary divergence showed strong clustering with CYP4H28 alleles and least divergence from the alleles respectively. The deduced protein was predicted to be found in the cytoplasm and likely to be phosphorylated but devoid of signal peptide, transmembrane helix and O-glycosylated sites. The secondary and tertiary structures were also generated.

    CONCLUSIONS: A cytochrome P450 pseudogene, CYP4H44P was cloned from Ae. aegypti. The pseudogene is homologous with CYP4H28 alleles and seems to have recently diverged from this group. Isolating this pseudogene is an important step for evaluating its biological role in the mosquito and for the evolutionary analysis of Ae. aegypti CYPs.

  4. Avicor SW, Wajidi MFF, Owusu EO
    Environ Sci Pollut Res Int, 2017 Sep;24(26):21138-21145.
    PMID: 28730366 DOI: 10.1007/s11356-017-9737-3
    Although evidence of mosquito coils' impact on disease epidemiology is limited, they are popularized as mosquito-borne disease prevention devices. Their usage affects the environment, human and mosquito health. This study investigated the perception, usage pattern and efficacy of coils in a predominantly poor malaria-endemic Ghanaian peri-urban area. Information on protection methods, perception and usage pattern was garnered using questionnaires. The efficacy of commonly used coils in the area was then assessed on the malaria vector, Anopheles gambiae, in a glass chamber. Sole or co-application of mosquito control methods and risky usage practices were reported. Coils were deemed harmful to humans and mosquitoes, and their perceived effectiveness varied, with several factors influencing their purchase. High d-allethrin concentration coils induced quicker mosquito knockdown; however, mortality was less than 85%. The coil usage pattern compromises users' health and can enhance mosquito tolerance to d-allethrin. The coils were ineffective against the vector, outlining a dichotomy between the users' perception of efficacy and the observed efficacy. Hence, the usage of other safer and more effective vector control methods should be encouraged to protect households.
  5. Chan HH, Mustafa FF, Zairi J
    Trop Biomed, 2011 Aug;28(2):464-70.
    PMID: 22041770
    Routine surveillance on resistant status of field mosquito populations is important to implement suitable strategies in order to prevent pest outbreaks. WHO test kit bioassay is the most frequent bioassay used to investigate the susceptibility status of field-collected mosquitoes, as it is relatively convenient to be carried out in the field. In contrast, the topical application of active ingredient is less popular in investigating the susceptibility status of mosquitoes. In this study, we accessed the susceptibility status of Aedes albopictus Skuse collected from two dengue hotspots on Penang Island: Sungai Dua and Persiaran Mayang Pasir. Two active ingredients: permethrin and deltamethrin, were used. WHO test kit bioassay showed that both wild strains collected were susceptible to the two active ingredients; while topical application assay showed that they were resistant. This indicated that WHO test kit bioassay less sensitive to low level of resistance compared to topical application assay. Hence, topical application is expected to be more indicative when used in a resistance surveillance programme.
  6. Al-Bayaty FH, Baharuddin N, Abdulla MA, Ali HM, Arkilla MB, ALBayaty MF
    Biomed Res Int, 2013;2013:684154.
    PMID: 24286083 DOI: 10.1155/2013/684154
    The objectives of this study were to evaluate the influence of cigarette smoking on gingival bleeding and serum concentrations of cotinine, haptoglobin, and alpha 1-antitrypsin in Malaysian smokers. A total of 197 male smokers and nonsmokers were recruited for this study. Plaque index, bleeding on probing (BOP), and levels of serum cotinine, haptoglobin, and alpha 1-antitrypsin were evaluated. The data were analyzed using SPSS version 20.0, with the significance level set at α ≤ 0.05. Linear regression analyses were performed. The mean cigarette consumption per day was 13.39 ± 5.75 cigarettes; the mean duration was 16.03 ± 8.78 years. Relatively low BOP values (26.05 ± 1.48) and moderate plaque indexes (51.35 ± 11.27) were found. The levels of serum cotinine (106.9 ± 30.71 ng/dL), haptoglobin (76.04 ± 52.48 mg/dL), and alpha 1-antitrypsin (141.90 ± 18.40 mg/dL) were significantly higher in smokers compared to non-smokers. Multiple logistic regression models for all variables and smokers demonstrated observed differences between BOP, the number of cigarettes per day, and duration of smoking, while serum cotinine, haptoglobin and alpha-1 antitrypsin levels showed no significant differences. Duration of smoking (years) and the cotinine level in serum showed a significant correlation with plaque index. The present analysis demonstrated that the duration of smoking in years, but not the number of cigarettes smoked per day, was associated with reduced gingival bleeding in smokers.
  7. Avicor SW, Wajidi MF, El-Garj FM, Jaal Z, Yahaya ZS
    Protein J, 2014 Oct;33(5):457-64.
    PMID: 25199940 DOI: 10.1007/s10930-014-9580-z
    Mosquito coils are insecticides commonly used for protection against mosquitoes due to their toxic effects on mosquito populations. These effects on mosquitoes could induce the expression of metabolic enzymes in exposed populations as a counteractive measure. Cytochrome P450 family 4 (CYP4) are metabolic enzymes associated with a wide range of biological activities including insecticide resistance. In this study, the efficacies of three commercial mosquito coils with different pyrethroid active ingredients were assessed and their potential to induce the expression of CYP4 genes in Aedes albopictus analyzed by real-time quantitative PCR. Coils containing 0.3 % D-allethrin and 0.005 % metofluthrin exacted profound toxic effects on Ae. albopictus, inducing high mortalities (≥90 %) compared to the 0.2 % D-allethrin reference coil. CYP4H42 and CYP4H43 expressions were significantly higher in 0.3 % D-allethrin treated mosquitoes compared to the other treated populations. Short-term (KT50) exposure to mosquito coils induced significantly higher expression of both genes in 0.005 % metofluthrin exposed mosquitoes. These results suggest the evaluated products provided better protection than the reference coil; however, they also induced the expression of metabolic genes which could impact negatively on personal protection against mosquito.
  8. Selvarajoo PD, Haque RA, Haziz UFM, Avicor SW, Wajidi MFF, Razali MR
    J Inorg Biochem, 2017 10;175:232-238.
    PMID: 28800547 DOI: 10.1016/j.jinorgbio.2017.07.030
    New synthesized bis-imidazolium salts that are linked by xylyl derivatives moiety, 1-4 was reacted with Ag2O to facilitate the formation of dinuclear Ag(I)-N-heterocyclic carbene (NHC) complexes, 5-8, respectively. All the synthesized ligand salts and complexes were characterized by1H and13C NMR, FTIR spectroscopy and elemental analysis. Molecular structures of compounds 3, 5, and 7 were elucidated by single crystal X-ray diffraction analyses. Larvicidal studies against the Aedes aegypti and Culex quinquefasciatus were carried out on all synthesized compounds following the World Health Organization standard larval susceptibility test. All the imidazolium salts were found inactive while the activity of the dinuclear Ag(I)-NHC complexes on mosquito larvae are varies with the nature of the ligands. Complex 7 has high activity on Ae. aegypti and Cx. quinquefasciatus, emphasising its potential as a larvicidal compound.
  9. Asekunowo PO, Haque RA, Razali MR, Avicor SW, Wajidi MFF
    Eur J Med Chem, 2018 Apr 25;150:601-615.
    PMID: 29550733 DOI: 10.1016/j.ejmech.2018.03.029
    A series of four benzimidazolium based nitrile-functionalized mononuclear-Ag(I)-N-heterocyclic carbene and binuclear-Ag(I)-N-heterocyclic carbene (Ag(I)-NHC) hexafluorophosphate complexes (5b-8b) were synthesized by reacting the corresponding hexafluorophosphate salts (1b-4b) with Ag2O in acetonitrile, respectively. These compounds were characterized by 1H NMR, 13C NMR, IR, UV-visible spectroscopic techniques, elemental analyses and molar conductivity. Additionally, 8b was structurally characterized by single crystal X-ray diffraction technique. Preliminary in vitro antibacterial evaluation was conducted for all the compounds against two standard bacteria; gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial strains. Most of the Ag(I)-NHC complexes (5b-8b) showed moderate to good antibacterial activity with MIC values in the range of 12.5-100 μg/mL. Especially, compound 8b exhibited promising anti-Staphylococcus aureus activity with a low MIC value (12.5 μg/mL). However, all the hexafluorophosphate salts (1b-4b) were inactive against the bacteria strains. The preliminary interactive investigation revealed that the most active compound, 8b, could effectively intercalate into DNA to form 8b-DNA complex which shows a better binding ability for DNA (Kb = 3.627 × 106) than the complexes 5b-7b (2.177 × 106, 8.672 × 105 and 6.665 × 105, respectively). Nuclease activity of the complexes on plasmid DNA and Aedes albopictus genomic DNA was time-dependent, although minimal. The complexes were larvicidal to the mosquito, with 5b, 6b and 8b being highly active. Developmental progression from the larval to the adult stage was affected by the complexes, progressively being toxic to the insect's development with increasing concentration. These indicate the potential use of these complexes as control agents against bacteria and the dengue mosquito Ae. albopictus.
  10. Hashim AM, Mustafa F, Rahman SF, Rahman AR
    Sensors (Basel), 2011;11(8):8127-42.
    PMID: 22164066 DOI: 10.3390/s110808127
    A Schottky diode has been designed and fabricated on an n-AlGaAs/GaAs high-electron-mobility-transistor (HEMT) structure. Current-voltage (I-V) measurements show good device rectification, with a Schottky barrier height of 0.4349 eV for Ni/Au metallization. The differences between the Schottky barrier height and the theoretical value (1.443 eV) are due to the fabrication process and smaller contact area. The RF signals up to 1 GHz are rectified well by the fabricated Schottky diode and a stable DC output voltage is obtained. The increment ratio of output voltage vs input power is 0.2 V/dBm for all tested frequencies, which is considered good enough for RF power detection. Power conversion efficiency up to 50% is obtained at frequency of 1 GHz and input power of 20 dBm with series connection between diode and load, which also shows the device's good potential as a rectenna device with further improvement. The fabricated n-AlGaAs/GaAs Schottky diode thus provides a conduit for breakthrough designs for RF power detectors, as well as ultra-low power on-chip rectenna device technology to be integrated in nanosystems.
  11. Redhwan AA, Low WY, Mustafa FM, Robert C, Ali A
    MyJurnal
    This study aimed to determine the perceptions and opinions of medical students about food allergy. Universal sampling was used to conduct focus group discussions. The majority of the participants 40 (67%) mentioned that the common symptoms of food allergy are: skin rashes, swollen lips, diarrhea, vomiting, bronchospasm, redness, itchiness, difficulty in breathing, stomach ache and fever. Majority of participants mentioned that seafood is the food that can cause most food allergies 52 (87%), followed by tree nuts 25 (42%), peanuts and dairy products 19 (32%). Regarding the most allergenic food named by the participants are seafood 23 (38%); followed by milk and dairy products 5 (8%) and nuts 5 (8%). The majority of participants mentioned that food allergy can be fatal 48 (80%), a child can catch food allergy 57 (95%), and 10 of 100 people would have food allergy 31 (52%). Half of the participants 30 (50%) mentioned that it is very hard to care for children with food allergy. The majority of participants mentioned that food allergies do run in families 50 (83%), avoiding allergenic food is the best preventive methods 36 (60%) and that food allergy can be treated and will go away and 32 (53%). This study showed that in spite of sufficient knowledge among medical students about food allergy, some misconceptions still exist such as the high prevalence of food allergy and that food allergy can be treated and will go away. Therefore, there is a need for improving the continuous medical education among medical students with regard to food allergy because they are our future physicians.
  12. Ramanathan N, Kamaruddin KA, Othman A, Mustafa F, Awang MS
    Malays J Med Sci, 2016 May;23(3):92-4.
    PMID: 27418876 MyJurnal
    Cystic meningioma is a rare form of intracranial meningioma. Meningiomas are typically solid tumors but may rarely have cystic components. The diagnosis of cystic meningioma is clinically challenging as the finding of multiple intra-axial tumors, including metastatic tumors, is relatively common. We report a case of cystic meningioma initially diagnosed as a metastatic tumor from a recurrence of acute lymphoid leukemia. However, postoperative histopathological examination demonstrated an atypical meningioma.
  13. Aksu F, Topacoglu H, Arman C, Atac A, Tetik S, Hasanovic A, et al.
    Surg Radiol Anat, 2009 Sep;31 Suppl 1:95-229.
    PMID: 27392492 DOI: 10.1007/BF03371486
    Conference abstracts: Malaysia in affiliation
    (1). PO-211. AGE-SPECIFIC STRESS-MODULATED
    CHANGES OF SPLENIC IMMUNOARCHITECTURE
    IN THE GROWING BODY. Marina Yurievna Kapitonova, Syed Baharom Syed Ahmad Fuad, Flossie Jayakaran; Faculty of Medicine, Universiti Teknologi MARA, Shah Alam, Malaysia
    [email protected]
    (2). PO-213. A DETAILED OSTEOLOGICAL STUDY OF THE ANOMALOUS GROOVES NEAR THE
    MASTOID NOTCH OF THE SKULL. ISrijit Das, 2Normadiah Kassim, lAzian Latiff, IFarihah Suhaimi, INorzana Ghafar, lKhin Pa Pa Hlaing, lIsraa Maatoq, IFaizah Othman; I Department of Anatomy, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia; 2 Department of Anatomy, Universiti Malaya, Kuala Lumpur, Malaysia. das_sri [email protected]
    (3). PO-21S. FIRST LUMBRICAL MUSCLE OF THE
    PALM: A DETAILED ANATOMICAL STUDY WITH
    CLINICAL IMPLICATIONS. Srijit Das, Azian Latiff, Parihah Suhaimi, Norzana Ghafar, Khin Pa Pa Hlaing, Israa Maatoq, Paizah Othman; Department of Anatomy, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia. [email protected]
    (4). PO-336. IMPROVEMENT IN EXPERIMENTALLY
    INDUCED INFRACTED CARDIAC FUNCTION
    FOLLOWING TRANSPLANTATION OF HUMAN
    UMBILICAL CORD MATRIX-DERIVED
    MESENCHYMAL CELLS. lSeyed Noureddin Nematollahi-Mahani, lMastafa Latifpour, 2Masood Deilami, 3Behzad Soroure-Azimzadeh, lSeyed
    Hasan Eftekharvaghefi, 4Fatemeh Nabipour, 5Hamid
    Najafipour, 6Nouzar Nakhaee, 7Mohammad Yaghoobi, 8Rana Eftekharvaghefi, 9Parvin Salehinejad, IOHasan Azizi; 1 Department of Anatomy, Kerman University of Medical Sciences, Kerman, Iran; 2 Department of Cardiosurgery, Hazrat-e Zahra Hospital, Kerman, Iran; 3 Department of Cardiology, Kerman University of Medical Sciences, Kerman, Iran; 4 Department of Pathology, Kerman University of Medical Sciences, Kerman, Iran; 5 Department of Physiology, Kerman University of Medical Sciences, Kerman, Iran; 6 Department of Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran; 7 Department
    of Biotechnology, Research Institute of Environmental Science, International Center for Science, High Technology & Environmental Science, Kerman, Iran; 8 Students Research Center, Kerman University of Medical Sciences, Kerman, Iran; 9 Institute of Bioscience, University Putra Malaysia,
    Kuala Lumpur, Malaysia; 10 Department of Stem Cell, Cell Science Research Center, Royan Institute, ACECR, Tehran, Iran. [email protected]
    (5).
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