Displaying publications 1 - 20 of 80 in total

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  1. Othman, M., Ahmad, K.
    ASM Science Journal, 2008;2(2):183-183.
    MyJurnal
    Comet Lulin was discovered by Lin Chi-Sheng and Ye Quanzhi using the 16-inch telescope at Lulin Observatory in Nantou, Taiwan in 2007. According to Brian Marsden of the Smithsonian Astrophysical Observatory, it reached its perihelion on 10 January 2009 at a distance of 113 million
    km from the Sun. It moves in a very nearly parabolic retrograde (‘backwards’ compared to the movement of the planets) orbit at an inclination of 1.6 degrees from the ecliptic (“Newfound Comet Lulin to Grace Night Skies”). http://www.space.com/spacewatch/090206-ns-cometlulin.html). It passed nearest to the Earth at a distance of 61 million km on 23 February 2009.
  2. Othman, M., Ahmad, K.
    ASM Science Journal, 2007;1(2):181-182.
    MyJurnal
    Comet 17P/Holmes was discovered by Edwin Holmes on 6 November 1892 while he was conducting regular observations of the Andromeda Galaxy (M31). Calculations using observation of its orbits established the perihelion date as 13 June and the orbital period as 6.9 years. The 1899 and 1906 appearances were observed, but the comet was only seen again in 1964. The comet has since been
    observed on every subsequent return.
  3. Ahmad K
    Int J Speech Lang Pathol, 2010 Aug;12(4):317-9; discussion 329-32.
    PMID: 20590514 DOI: 10.3109/17549507.2010.483017
    Speech-language pathologists (SLPs) practising in Malaysia face similar dilemmas as their counterparts in more developed countries when it comes to deciding on discharge/termination of services for their patients. Furthermore, discharge dilemmas appear to be a frequent and inevitable part of their everyday practice. In an interview conducted for the purpose of this paper, it was clear that many SLPs found it difficult to articulate or justify the process they took to reach a decision on whether or not to terminate their services or discharge their patients. Much of the difficulty is anchored on the need to be realistic and function within the confines of limited resources. Malaysian SLPs were aware of the ideals that had to be abandoned along the way but had not allowed guilt to dissuade or discourage them from providing what they perceived as the next best available service. The not-so ideal decisions made by these SLPs may be frowned upon by international standards but must be examined within the local historical perspective of the development of the SLP profession in Malaysia. The dilemma will continue until the country produces SLPs in sufficient numbers but the profession is reminded that less-than-ideal practices may perpetuate over time into unhealthy traditions that will require major efforts to be undone.
  4. Ho CC, Ahmad K
    J Colloid Interface Sci, 1999 Aug 1;216(1):25-33.
    PMID: 10395758
    The effect of metal cations, both nonhydrolyzable and hydrolyzable, on the zeta potential of palm olein emulsions stabilized by the nonionic emulsifier, polyoxyethylene nonyl phenyl ether, was investigated as a function of pH and cation concentrations, respectively. The oil drops were found to be negatively charged in the presence of simple mono- and divalent cations. Charge reversal of the oil drops was observed when hydrolyzable cations (Zn2+, Cu2+, Fe3+, and Al3+) were used and the behavior is strongly dependent on the type of cation, its concentration, and the pH of the dispersion. The results are discussed in terms of current theories of electrophoresis and adsorption-precipitation at interfaces. The chemical free energies of adsorption of the cations were calculated. Copyright 1999 Academic Press.
  5. Chellappa M, Ahmad K
    Med J Malaysia, 1978 Mar;32(3):245-6.
    PMID: 683051
  6. Alafeef AK, Ariffin F, Zulkurnain M
    Foods, 2020 Aug 29;9(9).
    PMID: 32872507 DOI: 10.3390/foods9091197
    Selenium is an essential micronutrient with significant antioxidant activity promising in mitigating the formation of acrylamide during high-temperature roasting. In this study, green coffee beans pretreated with selenium (Se-coffee) were investigated on their selenium uptake, selenium retention in green and roasted beans, antioxidant activities, and formation of acrylamide during conventional and superheated steam roasting. Comparisons were made with positive (pretreated without selenium) and negative (untreated) controls. The acrylamide formation was significantly inhibited in Se-coffee (108.9-165.3 μg/kg) compared to the positive and negative controls by 73.9% and 52.8%, respectively. The reduction of acrylamide by superheated steam roasting only observed in the untreated coffee beans (negative control) by 32.4% parallel to the increase in its antioxidant activity. Selenium pretreatment significantly increased antioxidant activity of the roasted Se-coffee beans after roasting although soaking pretreatment significantly reduced antioxidant activity in the green beans. Acrylamide reduction in the roasted coffee beans strongly correlated with the change in antioxidant capacities after roasting (∆FRAP, 0.858; ∆DPPH, 0.836). The results indicate that the antioxidant properties of the organic selenium suppressed acrylamide formation during coffee roasting.
  7. Ahmad K, Aziz Z
    J Ethnopharmacol, 2012 May 7;141(1):446-50.
    PMID: 22440259 DOI: 10.1016/j.jep.2012.03.009
    ETHNOPHARMACOLOGICAL RELEVANCE:
    The consumption of Mitragyna speciosa (MS) for its psychoactive effects is widely reported amongst people in the villages in Thailand and Malaysia even though its use is illegal.
    AIM OF THE STUDY: This study examined the pattern of MS use, its reported effects and explored its potential to cause dependence.
    MATERIALS AND METHODS: We used both convenience and snowball-sampling methods to recruit participants in a border town between two northern states in Malaysia. Face-to-face interviews were conducted with the use of a structured questionnaire on 562 respondents who gave oral consent to participate in the study.
    RESULTS: The response rate was 91%. The majority of the respondents (88%) reported daily use of MS. The main mode of using MS was by drinking the MS extract as tea (90%). The mean age of starting MS use was 28.3 (SD=8.1) years. A variety of reasons were given for using MS including for social and recreational needs, stamina and physical endurance, pain relief and improved sexual performance. Despite its reported usefulness in weaning off opiate addiction, 460 (87%) admitted they were not able to stop using MS. Only education level had a statistically significant association with the ability to stop or not stop the use of MS (χ(2)=31.0, df=1, p<0.001). Significantly higher proportions of those with a lower education level (38%) were able to stop using MS compared to respondents with a higher education level.
    CONCLUSIONS: Our study provides important information on the pattern of MS use, its effects and its potential to cause addiction, as there has been growing interest in MS as evidenced by the number of advertisements for its sale on the Internet. Future study is required to explore its psychological and social impact on users.
  8. Razi Hadi A, Said H, Ahmad K
    Med J Malaysia, 1988 Mar;43(1):74-83.
    PMID: 3244325
    Foreign bodies in the laryngotracheobronchial tree are not uncommon. Their clinical presentations, the radiological and endoscopic findings in sixteen cases that presented to the Department of Otorhinolaryngology, Universiti Kebangsaan Malaysia were reviewed. The technique of removal is also discussed.
    Study site: Hospital Kuala Lumpur, Malaysia (UKM unit)
  9. Nasarudin NM, Mohd Saiboon I, Ismail AK
    Eur J Emerg Med, 2013 Oct;20(5):335-8.
    PMID: 22976462 DOI: 10.1097/MEJ.0b013e328358fa40
    Dengue fever is endemic in Malaysia and poses a significant problem to the national health system. Because of its nonspecific clinical features, it creates clinical and administrative uncertainties. We evaluated the role of an emergency department short-stay ward (EDSSW) in the management of dengue fever in the Universiti Kebangsaan Malaysia Medical Centre (UKMMC).
  10. Borhanuddin BK, Abdul Latiff H, Mohamed Yusof AK
    Cardiol Young, 2022 Dec;32(12):1994-1998.
    PMID: 35707919 DOI: 10.1017/S1047951122000154
    BACKGROUND: CT is an accepted non-invasive imaging tool to assess the coronary arteries in adults; however, its utilisation in children is limited by high heart rate and lack of standardised protocol. We sought to assess diagnostic quality and factors that affect image quality of CT in assessing coronary artery lesions in Kawasaki patients less than 18 years of age.

    METHODOLOGY: CT coronary angiography was performed on patients with Kawasaki disease diagnosed with coronary aneurysm or suspected to have coronary stenosis. Studies were performed using electrocardiogram-gated protocols. General anaesthesia was used in patients who were not cooperative for breathing control. Heart rate, image quality, and effective radiation dose were documented.

    RESULTS: Fifty-two Kawasaki patients underwent CT coronary angiography to assess coronary artery lesions. Median heart rate was 88 beats per minute (range 50-165 beats/minute). Image quality was graded as excellent in 34 (65%) patients, good in 17 (32%), satisfactory in 1, and poor in 1 patient. Coronary artery aneurysm was found in 25 (bilateral = 6, unilateral = 19, multiple = 11). Thrombus was found in 11 patients resulting in partial and total occlusion in 8 and 3 patients, respectively. Coronary stenosis was noted in 2 patients. The effective radiation dose was 1.296 millisievert (median 0.81 millisievert). Better diagnostic imaging quality was significantly related to lower heart rate (p = 0.007).

    CONCLUSION: Electrocardiogram-triggered CT coronary angiography provides a good diagnostic assessment of coronary artery lesions in children with Kawasaki disease.

  11. Ngew KY, Tay HZ, Yusof AKM
    BMC Cardiovasc Disord, 2023 Nov 08;23(1):545.
    PMID: 37940867 DOI: 10.1186/s12872-023-03536-w
    PURPOSE: Percutaneous coronary intervention (PCI) is a common treatment modality for coronary artery disease. Accurate prediction of patients at risk for complications and hospital readmission after PCI could improve the overall clinical management. We aimed to develop and validate predictive models to predict any cardiac event within a year post PCI procedure.

    METHODS: This is a retrospective cohort study utilizing data from the National Cardiovascular Disease (NCVD)-PCI registry. The data collected (N = 28,007) were split into training set (n = 24,409) and testing set (n = 3598). Four predictive models (logistic regression [LR], random forest method, support vector machine [SVM], and artificial neural network) were developed and validated. The outcome on risk prediction were compared.

    RESULTS: The demographic and clinical features of patients in the training and testing cohorts were similar. Patients had mean age ± standard deviation of 58.15 ± 10.13 years at admission with a male majority (82.66%). In over half of the procedures (50.61%), patients had chronic stable angina. Within 1 year of follow up mortality, target vessel revascularization (TVR), and composite event of mortality and TVR were 3.92%, 9.48%, and 12.98% respectively. LR was the best model in predicting mortality event within 1-year post-PCI (AUC: 0.820). SVM had the highest discrimination power for both TVR event (AUC: 0.720) and composite event of mortality and TVR (AUC: 0.720).

    CONCLUSIONS: This study successfully identified optimal prediction models with the good discriminatory ability for mortality outcome and good discrimination ability for TVR and composite event of mortality and TVR with a simple machine learning framework.

  12. Aftab SMA, Ahmad KA
    PLoS One, 2017;12(8):e0183456.
    PMID: 28850622 DOI: 10.1371/journal.pone.0183456
    The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.
  13. Zhao L, Yang L, Ahmad K
    Hum Exp Toxicol, 2023;42:9603271221146780.
    PMID: 36607234 DOI: 10.1177/09603271221146780
    OBJECTIVES: Kaempferol (KMF), has beneficial effects against hepatic lipid accumulation. In this study, we aimed to investigate molecular mechanism underlying the protective effect of KMF on lipid accumulation.

    METHODS: HepG2 cells were treated with different concentrations of KMF and 0.5 mM palmitate (PA) for 24  h. The mRNA and protein levels of genes involved in lipid metabolism were evaluated using real-time PCR and western blot. The expression of Nrf2 was silenced using siRNA.

    RESULTS: Data indicated that KMF (20 μM) reversed PA-induced increased triglyceride (TG) levels and total lipid content. These effects were accompanied by down-regulation of the mRNA and protein levels of lipogenic genes (FAS, ACC and SREBP1), and up-regulation of genes related to fatty acid oxidation (CPT-1, HADHα and PPARα). Kaempferol significantly decreased the levels of the oxidative stress markers (ROS and MDA) and enhanced the activities of antioxidant enzymes SOD and GPx in PA-challenged cells. Luciferase analysis showed that KMF increased the transactivation of Nrf2 in hepatocytes. The results also revealed that KMF-mediated activation of Nrf2 target genes was suppressed by Nrf2 siRNA. Furthermore, Nrf2 siRNA abolished the KMF-induced reduction in ROS and MDA levels in PA treated cells. In addition, the inhibitory effect of KMF on TG levels and the mRNA and protein levels of FAS, ACC and SREPB-1 were significantly abolished by Nrf2 inhibition. Nrf2 inhibition also suppressed the KMF-induced activation of genes involved in β oxidation (CPT-1 and PPAR-α).

    CONCLUSION: The results suggest that KMF protects HepG2 cells from PA-induced lipid accumulation via activation of the Nrf2 signaling pathway.

  14. Ahmad K, Yan Y, Bless D
    J Voice, 2012 Nov;26(6):751-9.
    PMID: 22633334 DOI: 10.1016/j.jvoice.2011.12.002
    A high proportion of the geriatric population suffers from presbylaryngis and presbyphonia; however, our knowledge of vibratory patterns in this population is almost nonexistent. In this study, we investigate the vocal fold vibratory patterns of healthy elderly females to determine which features or combination of them could best describe the geriatric voices.
  15. Ahmad K, Yan Y, Bless DM
    J Voice, 2012 Mar;26(2):239-53.
    PMID: 21621975 DOI: 10.1016/j.jvoice.2011.02.001
    The purpose of the study was to investigate relationships between vocal fold vibrations and voice quality. Laryngeal images obtained from high-speed digital imaging (HSDI) were examined for their open-closed timing characteristics and perturbation values. A customized software delineated the glottal edges and used the Hilbert transform-based method of analysis to provide objective quantification of glottal perturbation. Overlay tracings of the transformed glottal cycles provided visual patterns on the overall vibratory dynamics. In this paper, we described the use of this method in looking at vibratory characteristics of a group of young female speakers (N=23). We found that, females with no voice complaints and who had been perceived to have normal voices were not a homogeneous group in terms of their glottal vibratory patterns during phonation. Their vibratory patterns showed characteristics similar to exemplar voices targeted to be clear (50%), pressed (27%), breathy (15%), or a mixed quality (8%). Perturbation range in terms of cycle-to-cycle frequency and amplitude was small and did not discriminate patterns. All these patterns yielded perceptually normal voices suggesting that in normal young speakers, the level of perturbation may be more important to the judgment than the actual pattern of closure.
  16. Mohd Ibrahim H, Mohamed Yusoff FH, Ahmad K, Van Dort S
    Med J Malaysia, 2015 Dec;70(6):321-5.
    PMID: 26988203 MyJurnal
    INTRODUCTION: Little is known about the treatment outcomes of children with cleft lip and/or palate (CLP) receiving surgical care for primary lip and palate closure in Malaysia.

    OBJECTIVES: This study examined the speech and hearing status of Malay-speaking children with CLP residing in Kuala Lumpur.

    METHODS: Parents whose children were between the age of 5 and 7 years were recruited via the Cleft Lip and Palate Association of Malaysia (CLAPAM) registry. Parents completed a survey and the children completed a speech and hearing assessment at the Audiology and Speech Sciences Clinic, Universiti Kebangsaan Malaysia.

    OUTCOMES: Speech measures include nasality rating, nasalance scores, articulation errors and speech intelligibility rating, while hearing measures include hearing thresholds and tympanometry results for each child.

    RESULTS: Out of 118 registered members who fulfilled the inclusion criteria, 21 agreed to participate in the study. The overall speech and hearing status of children in this sample were poor. Only four (19%) participants had normal speech intelligibility rating and normal hearing bilaterally. In terms of overall cleft management, only four (19%) participants were seen by a cleft team while seven (33%) had never had their hearing tested prior to this study.

    CONCLUSION: Participants in this sample had poor outcomes in speech and hearing and received uncoordinated and fragmented cleft care. This finding calls for further large scale research and collaborative efforts into improving and providing centralised, multidisciplinary care for children born with CLP.

  17. Tan LL, Ahmad K, Kareem BA, Harwant S
    Med J Malaysia, 2001 Jun;56 Suppl C:52-6.
    PMID: 11814250 MyJurnal
    An epidemiological study of 101 consecutive musculoskeletal sarcomas seen at the Institute of Radiotherapy and Oncology between 1995 and 1999 inclusive was carried out. The commonest sarcomas seen were osteosarcoma, rhabdomyosarcoma, Ewing's Sarcoma, liposarcoma, leimyosarcoma, malignant fibrous histiocytoma and chondrosarcoma; which collectively accounted for 84.2% of the group. Thirty patients (29.7%) presented with metastases. The commonest site of occurrence was lower extremity with 47.5%, followed by 34.7% in the trunk and peritoneum/axial skeleton, 9.9% in the head and neck region; and 7.90 in the upper extremity. We found no apparent relationship between race and incidence osteosarcoma and Ewing's sarcoma, as was reported by previous workers.
  18. Din HM, Rashed O, Ahmad K
    Trop Life Sci Res, 2020 Oct;31(3):29-45.
    PMID: 33214854 DOI: 10.21315/tlsr2020.31.3.3
    Fusarium wilt disease is one of the most problematic and destructive disease in cucumber production. The causative agents are Fusarium oxysporum and F. solani. These pathogens are soil borne and transmitted through infested soil and water. A field survey was conducted to study the disease prevalence in the major growing areas of cucumber in Peninsular Malaysia. Field study revealed that the disease was highly prevalence in the field with the disease incidence was in the range of 10%-60%. The morphological properties of F. oxysporum are microconidia (3.8-15.7 μm × 2.9-4.9 μm), macroconidia (14.8-38.5 μm × 2.4-5.7 μm) and number of septate was 1-4. While for F. solani are microconidia (3.39-14.63 μm × 2.36-4.44 μm), macroconidia (7.22-50.46 μm × 2.43-6.14 μm) and number of septate was 1-5. Based on molecular identification had confirmed that the disease is caused by F. oxysporum and F. solani with similarity index of 99%-100% based on internal transcribed spacer (ITS) gene sequences. The pathogenicity test showed that the symptoms of Fusarium wilt disease was firstly appeared as yellowing of old leaves. Progressively, the infected plant will be wilted and finally died. The outputs of this study are highly important to establish an effective disease management programme to reduce disease prevalence and yield loss in the field.
  19. Surendran A, Siddiqui Y, Ahmad K, Fernanda R
    Plants (Basel), 2021 Aug 28;10(9).
    PMID: 34579330 DOI: 10.3390/plants10091797
    The threat of Ganoderma boninense, the causal agent of basal stem rot disease, in the oil palm industry warrants finding an effective control for it. The weakest link in the disease management strategy is the unattended stumps/debris in the plantations. Hence, this study aimed to determine whether the selected phenolic compounds could control G. boninense in inoculated oil palm woodblocks and restrict wood biodegradation. Results indicated a significant reduction in the wood mass loss when treated with all the phenolic compounds. Surprisingly, syringic and vanillic acids behaved ambivalently; at a lower concentration, the wood mass loss was increased, but it decreased as the concentrations were increased. In all four phenolic compounds, the inhibition of mass loss was dependent on the concentration of the compounds. After 120 days, the mass loss was only 31%, with 63% relative degradation of lignin and cellulose, and 74% of hemicellulose and wood anatomy, including silica bodies, were intact in those woodblocks treated with 1 mM benzoic acid. This study emphasizes the physicochemical and anatomical changes occurring in the oil palm wood during G. boninense colonization, and suggests that treating oil palm stumps with benzoic acid could be a solution to reducing the G. boninense inoculum pressure during replantation in a sustainable manner.
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