Displaying publications 1 - 20 of 149 in total

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  1. Fulltext A study on the effects of environment on curing characteristics of thixotropic and room temperature cured epoxy-based adhesives using DMTA
    Ahmad, Z., Rohana, H., Md Tahir, P.
    ASM Science Journal, 2013;7(1):37-58.
    MyJurnal
    This study investigated the thermal properties of three room temperature curing adhesives containing nano particles which were thixotropic and shear thinning which allowed injection into overhead holes when exposed to different environmental conditions. Viscosity and shear stress of the adhesives were measured as a function of shear rate. The thermal behaviour of the adhesives were measured using dynamic mechanical thermal anylisis following exposures to different temperatures and humidities which included temperatures of 20 degrees Celcius, 30 degrees Celcius and 50 degrees Celcius, relative humidities of 65% RH, 75% RH 95% RH soaked in water at 20 degrees Celcius and placed in the oven at 50 degrees Celcius. The dynamic thermal properties reported include storage and loss modulus, the loss tangent and the glass transition temperature ( Tg ). For nano- and micro-particles filled adhesives, the Tg increased with the temperature increase, even though the adhesives was subjected to high humidity and this was due to further cross-linking. The results showed that room temperature cured epoxies were only partially cured at room temperature.
  2. Fulltext Mechanical properties of wood-wool cement composite board manufactured using selected Malaysian fast grown timber species
    Ahmad, Z., Wee, L.S., Fauzi, M.A.
    ASM Science Journal, 2011;5(1):27-35.
    MyJurnal
    This paper reports the mechanical properties of cement composite boards made using wood-wool from a lesser known Malaysian timber species. A total of 108 specimens were fabricated using Portland cement (Type I) and wood-wool from Kelampayan (Neolamarckia cadamba). The cement to wood ratio of the specimens was 2 to 1 by weight. The aim of the study was to determine the density; flexural, compressive and tensile strength of wood-wool cement composite boards (WWCCB) by studying boards with wood-wool sized 1.5 mm, 2.5 mm and 3.5 mm and board thickness 25 mm, 50 mm and 75mm. The physical and mechanical properties of the boards were evaluated according to ASTM D 1037-96a (Standard testing method for evaluating properties of wood-based fibre and particle panel materials) and MS934:1986. Results showed that mechanical properties of WWCCB were greatly influenced by the density; as the density decreased, the mechanical strengths also decreased. However, the strength properties of the composite boards did not display a similar trend when subjected to different types of loading conditions. The compressive strength increased with thicker boards (50 mm and 75 mm) but the modulus of elasticity and modulus of rupture declined as the thickness of the board was increased.
  3. Fulltext Source of information on sexual and reproductive health among secondary schools’ girls in the Klang Valley
    Kamrani, M.A., Sharifah Zainiyah, S.Y., Hamzah, A., Ahmad, Z.
    Malaysian Journal of Public Health Medicine, 2011;11(1):29-35.
    MyJurnal
    Adolescents are known to obtain information regarding sexual and reproductive health from a variety of sources and not just during formal lessons in schools. This cross-sectional descriptive study was carried out to determine the source of information on sexual and reproductive health among Form four secondary schools girls in the Klang Valley as well as parents’ relationship profile. A total of 520 secondary school girls were recruited for the study. In this study, the source of information on puberty and sexual topics were categorized as follows: first level of importance - mothers, second level of importance - siblings, third level of importance - fathers, fourth level of importance - friends, fifth level of importance - teachers and sixth level of importance - books/internet. A majority of respondents agreed that their mothers were the first level of importance they sought for information on puberty (74.8%) and sexual topics (53.8%). Thirty nine point three percent (39.3%) of respondents reported it was very easy to have a dialogue with their mothers while only 10.0% of the respondents said it was very easy to have a dialogue with their fathers. While this was the case, only 6.3% of the respondents reported discussing sex-related matter with their mothers.
  4. Role of the cell envelope in the antibacterial activities of polymyxin B and polymyxin B nonapeptide against Escherichia coli
    Sahalan AZ, Dixon RA
    Int J Antimicrob Agents, 2008 Mar;31(3):224-7.
    PMID: 18083010
    The role of membrane permeabilisation and disruption in the mechanism of action of some polymyxin analogues against Gram-negative organisms is contentious. The effects of polymyxin B (PMB) and its analogue polymyxin B nonapeptide (PMBN) on Escherichia coli envelopes should correlate, but previous work by other workers suggests that PMBN has a different mode of action. This study has reassessed the biochemical techniques used previously and has shown that, in contrast to previous studies, PMBN (a well-characterised antibacterial synergist) readily releases periplasmic proteins and lipopolysaccharide from treated E. coli at subinhibitory concentrations in normal physiological buffer conditions. We conclude that, when tested with appropriate methodology, PMBN closely correlates with the early effects of PMB on the cell envelope of E. coli and this study shows that it is now consistent with the accepted interactions of membrane-active agents against Gram-negative cells.
  5. Simulation of Lamb wave reflections at plate edges using the semi-analytical finite element method
    Ahmad ZA, Gabbert U
    Ultrasonics, 2012 Sep;52(7):815-20.
    PMID: 22727492 DOI: 10.1016/j.ultras.2012.05.008
    In typical Lamb wave simulation practices, effects of plate edge reflections are often not considered in order to simplify the wave signal interpretations. Methods that are based on infinite plates such as the semi-analytical finite element method is effective in simulating Lamb waves as it excludes the effect of plate edges. However, the inclusion of plate edges in a finite plate could render this method inapplicable, especially for transient response simulations. Here, by applying the ratio of Lamb mode reflections at plate edges, and representing the reflection at plate edges using infinite plate solutions, the semi-analytical finite element method can be applied for transient response simulation, even when the plate is no longer infinite.
  6. Fulltext Oxidative stress and its association with cardiovascular disease in chronic renal failure patients
    Hambali Z, Ahmad Z, Arab S, Khazaai H
    Indian J Nephrol, 2011 Jan;21(1):21-5.
    PMID: 21655165 DOI: 10.4103/0971-4065.75218
    Cardiovascular disease (CVD) is responsible for the majority of deaths in chronic renal failure (CRF). Oxidative stress plays a key role in pathogenesis of atherosclerosis and CVD, which is promoted by the production of reactive oxygen species (ROS) and impaired antioxidant enzymes. These ROS react with nitric oxide (NO) to produce cytotoxic reactive nitrogen species that cause oxidative injury to the endothelium. This study evaluated biomarkers of oxidative stress, NOx (total NO(2) and NO(3)), and superoxide dismutase (SOD) enzyme in normal control and CRF patients as case group and correlated their association with CVD. This cross sectional study involved 173 CRF patients on different modes of treatment (hemodialysis, continuous ambulatory peritoneal dialysis (CAPD), and predialysis). Of these, 74 had CVD. The control group consisted of 33 healthy subjects who had no history of CRF and CVD. Both NOx and SOD levels were significantly lower (P<0.05, P<0.001, respectively) in the case group. Comparing between CRF patients with and without CVD, SOD level was found to be significantly lower in CRF patients with CVD (P<0.05). Logistic regression analysis showed significant association of CVD event with age, male gender, diabetes, SOD level, and lipid profile in CRF patients. Oxidative stress occurs in the CRF patients with or without CVD. This study found that NOx and SOD levels were reduced in all CRF patients with or without CVD. However, it was noted that the levels of these biomarkers of oxidative stress were significantly lower in CRF patients with CVD compared with CRF patients without CVD. Therefore, these oxidative stress markers maybe contributing factors in the pathogenesis of CVD in patients with CRF.
  7. Fulltext Good oral health, adequate nutrient consumption and family support are associated with a reduced risk of being underweight amongst older Malaysian residents of publicly funded shelter homes
    Visvanathan R, Ahmad Z
    Asia Pac J Clin Nutr, 2006;15(3):400-5.
    PMID: 16837433
    A low body mass index in older people has been associated with increased mortality. The main objective of this study was to identify factors associated with low body mass indices [ BMIs] (< 18.5 kg/m2) in older residents of shelter care facilities in Peninsular Malaysia. 1081 elderly people (59% M) over the age of 60 years were surveyed using questionnaires determining baseline demographics, nutritional and cognitive status, physical function and psychological well being. Body mass index was also determined. Subjects were recruited from publicly funded shelter homes in Peninsular Malaysia. 14.3% of residents had BMIs < 18.5 kg/m2. Multivariate analyses (adjusted for age and sex) revealed that having no family (RR 1.98[95%CI 1.40-2.82], p<0.001) and negative responses to statement 3 [I eat few fruits or vegetables or milk products] (RR 0.62 [95% CI 0.42-0.90]; P= 0.013) and statement 5 [I have tooth or mouth problems that make it hard for me to eat] (RR 0.69 [95%CI 0.50-0.96]; P= 0.023) of the ' Determine Your Nutritional Health Checklist' were independently associated with low BMIs (<18.5 kg/m2). Older people with no family support were at risk of becoming underweight. Older people who consumed fruits, vegetables or milk or had good oral health were less likely to be underweight. Nutrient intake, oral health and social support were important in ensuring healthy body weight in older Malaysians.
  8. Fulltext Factors related to smoking habits of male secondary school teachers
    Naing NN, Ahmad Z
    Southeast Asian J. Trop. Med. Public Health, 2001 Jun;32(2):434-9.
    PMID: 11556602
    A cross-sectional study was conducted to identify the factors related to smoking habits of secondary school teachers in Kelantan, Malaysia. A total of 180 male teachers and trainee teachers from four secondary schools in Kelantan and a Teachers' Training College were interviewed by using a structured questionnaire. Cluster sampling was applied. The significant findings found were current smokers were found as high as 40.56%. Mean duration of smoking was 6.8 years and mean initiation age was 16.5 years. Trainee teachers had a significantly higher proportion of current smokers. There was a significant association between smoking status of teachers and their fathers' and perception of the hazards of smoking on health. Peer influence was found to be the major reason for smoking among smokers. Religious belief and care for health attitude prevented non-smokers from smoking. About 3/5 of smokers thought of quitting smoking and of these 1/4 had tried at least once. There was a significant difference of proportion of attempted quitting between regular and occasional smokers. Mass media was the best source of information on knowledge about smoking hazards. Anti-smoking campaigns should start as early as possible in schools. Lectures and talks on smoking should be included in the curriculum of teachers' training courses.
  9. Respiratory health of rice millers in Kelantan, Malaysia
    Musa R, Naing L, Ahmad Z, Kamarul Y
    Southeast Asian J. Trop. Med. Public Health, 2000 Sep;31(3):575-8.
    PMID: 11289024
    A cross sectional study was carried out to evaluate the effect of rice husk dust in rice millers in Malaysia. Altogether 69 workers participated in this study. They were interviewed using standardized questionnaires and lung function tests were performed. Chest tightness was among the common symptoms (34.9%) complained by workers. Age, duration of employment and smoking status were among the factors associated with respiratory symptoms (p < 0.01). Lung function tests revealed some degree of impairment compared to the healthy population.
  10. Fulltext Clinical significance of Mantoux test in Malaysian patients
    Yaacob I, Ahmad Z
    Med J Malaysia, 1990 Sep;45(3):231-4.
    PMID: 2152084
    The value of tuberculin skin testing in the diagnosis of active tuberculosis remains uncertain. Interpretation of tuberculin tests would be easier if the tuberculin test profiles in different communities were accurately known. We reviewed 468 Mantoux test reactions in patients coming to Hospital Universiti Sains Malaysia with suspected tuberculosis. Eighty six percent of patients with active tuberculosis had a positive Mantoux test. Forty two percent of the cases of positive Mantoux test did not have evidence of active tuberculosis. Most of these cases had evidence of past infection with tuberculosis. We conclude that Mantoux test is a sensitive but a non-specific test in the diagnosis of active tuberculosis.
    Study site: outpatients, inpatients; Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
  11. The early phase of acute myocardial infarction - a study of 100 cases
    Ng WH, Goh TH, Ahmad Z
    Family Practitioner, 1979;3(5):24-7.
  12. Fulltext Breastfeeding and weaning practices in rural communities of Kelantan
    Ahmad Z, Daw W, Isa A
    Malays J Nutr, 1996 Sep;2(2):148-54.
    PMID: 22692137 MyJurnal
    A survey of infant-feeding and weaning practices of 566 mothers, systematically sampled from 15 rural villages, randomly selected in the district of Tumpat, Kelantan was carried out. Almost all mothers (97.3%) breastfed their children, reinforcing the previously reported high incidence of breast-feeding among rural Malaysian mothers. One hundred and seventeen (21.3%) of the 551 children breastfed were also given mixed feeding with infant fomulae as well. Weaning started before 4 months of age in 28.3% of the children and after 6 months of age in 12.8% of the children. The 3 most common type of food used in weaning were Nestum (45.0%), rice porridge or paste (42.6%) and wheat porridge or cakes (11.5%). Forty eight children (12.1%) discontinued breastfeeding once weaning was initiated. The main reasons for initiating weaning was mothers' perception that there was insufficient milk and that the child was always hungry (55.7%). Most mothers were also given advice by the health clinic staff on weaning, including the timing and the suitable weaning foods to give. All of the mothers were able to name at least one commercial weaning food product available in their community.
  13. Fulltext The prevalence of undernutrition upon hospitalization in children in a developing country: A single hospital study from Malaysia
    Lee WS, Ahmad Z
    Pediatr Neonatol, 2017 10;58(5):415-420.
    PMID: 28330630 DOI: 10.1016/j.pedneo.2016.08.010
    BACKGROUND: Undernourished children who require hospital care have a longer duration of hospitalization and respond poorly to modern medical therapy. The objective of the present study was to ascertain the nutritional status of children admitted to a pediatric tertiary center in Malaysia and the risk factors leading to undernutrition upon admission.

    METHODS: In this cross-sectional, hospital-based study, anthropometric measurements [weight, length/height, mid-upper arm circumference (MUAC), triceps skinfold thickness were performed in 285 children aged from 3 months to 15 years who were admitted to University Malaya Medical Centre, Kuala Lumpur in November 2013. Acute (wasting) and chronic (stunting) undernutrition were defined as weight-for-height (WFH) and height-for-age (HFA) < -2 standard deviation (S.D.), respectively. Underweight was defined as weight-for-age < -2 S.D. For children aged between 1 and 5 years of age, World Health Organization definition for acute undernutrition (HFA 

  14. Fulltext The enhancement of driver seat comfort for small size car: a preliminary study
    Noor, N.S.M., Ghazalli, Z., Mamat, R., Kadirgama, K., Sani, M.S.M., Ahmad, Z., et al.
    Malaysian Journal of Public Health Medicine, 2016;16(10):0-0.
    MyJurnal
    Seating comfort is one of the important indicators while driving especially for a long hour drive. The objective of this study was to execute a preliminary study of survey and identify the discomfort of body while driving and after driving session by conducting a survey. The questionnaire developed was tested for its reliability. By using Cronbach’s Alpha, this paper’s contribution was found to be significant in which it provides a survey with acceptable test reliability in which the alpha (α) was 0.887. The survey was conducted on 30 students of University Malaysia Pahang (20 male and 10 female) with driving experience and valid driving license. The subjects should have experiences in driving small size car or mini car as well. The results showed that the body area that the drivers felt discomfort while driving and after driving should be known. The findings showed that the discomfort was intense at the neck, upper back, and lumbar while and after driving.
  15. The Cruveilhier-Baumgarten syndrome
    Chelvam P, Ahmad Z, Weng Hwa N
    Med J Malaysia, 1979 Mar;33(3):266-8.
    PMID: 522733
  16. Normal electrocardiogram after myocardial infarction
    Ng WH, Ahmad Z
    Med J Malaysia, 1978 Dec;33(2):128-32.
    PMID: 755162
  17. Fulltext The Conserved Molecular Determinants of Virulence in Dengue Virus
    Ahmad Z, Poh CL
    Int J Med Sci, 2019;16(3):355-365.
    PMID: 30911269 DOI: 10.7150/ijms.29938
    Dengue virus belongs to the Flaviviridae family which also includes viruses such as the Zika, West Nile and yellow fever virus. Dengue virus generally causes mild disease, however, more severe forms of the dengue virus infection, dengue haemorrhagic fever (DHF) and dengue haemorrhagic fever with shock syndrome (DSS) can also occur, resulting in multiple organ failure and even death, especially in children. The only dengue vaccine available in the market, CYD-TDV offers limited coverage for vaccinees from 9-45 years of age and is only recommended for individuals with prior dengue exposure. A number of mutations that were shown to attenuate virulence of dengue virus in vitro and/or in vivo have been identified in the literature. The mutations which fall within the conserved regions of all four dengue serotypes are discussed. This review hopes to provide information leading to the construction of a live attenuated dengue vaccine that is suitable for all ages, irrespective of the infecting dengue serotype and prior dengue exposure.
  18. Fulltext Career choices of physicians in Malaysia
    Ahmad Z, Jaafar R
    JUMMEC, 1999;4(1):47-50.
    A survey of career choices was conducted for two batches of physicians applying for a medical speciality course in Malaysian medical schools. There were a total of 952 applications, with 477 males and 475 females. Surgery ranked highest, followed by obstetrics and gynaecology, fanlily medicine and orthopaedic surgery. The minor specialities of otorhinolaryngology, psychiatry and pathology were the least popular choices. Questionnaires were sent to a random sample of 250 physicians in each batch to note factors affecting their choices of speciality. A total of 359 physicians responded, giving a response rate of 71.8%. Fixed hours of work and the ability to have direct contact with patients were relatively important factors for choice of speciality. Working as a clinical consultant was the nlost popular nature of employment while worliing in the health office, service consultant in a public hospital, a non-clinical lecturer in a university hospital and working in a private clinic were less popular choices for these physicians. KEYWORDS: Career choice; medical speciality; doctors; Malaysia.
  19. Fulltext Fibreoptic bronchoscopy--a Malaysian experience
    Yaacob I, Harun Z, Ahmad Z
    Singapore Med J, 1991 Feb;32(1):26-8.
    PMID: 2017700
    Two hundred and ninety-three bronchoscopies were done for 285 patients (78% males, 22% females) at Hospital University Sains Malaysia between 1984 and 1988. The mean age was 56.4 years (range 13 to 90 years). 70.2% of patients underwent bronchoscopies to confirm or exclude the diagnosis of carcinoma of the bronchus, out of which 58% were confirmed to have bronchial carcinoma. 77% of the 98 patients with visible endobronchial tumours had biopsy specimens diagnostic of malignancy. Brushing and washing cytology increased the positive yield to 92%. The commonest histological type of bronchial carcinoma identified was squamous cell carcinoma (48.1%), followed by small cell carcinoma (27.1%), anaplastic/undifferentiated carcinoma (12.9%), adenocarcinoma (9.4%) and large cell carcinoma (2.4%). Bronchoscopy for the investigation of haemoptysis identified the commonest cause as 'bronchitis'. There were no complications noted in our series. Notable differences of our experience compared to that of the western series were the high percentage of bronchoscopy done for infective respiratory disorders and the younger age of our patients.
  20. Fulltext Lung cancer in Kelantan
    Yaacob I, Ahmad Z, Harun Z
    Med J Malaysia, 1990 Sep;45(3):220-4.
    PMID: 1966930
    A review of 119 patients (88 males and 31 females) with carcinoma of the lung seen at the Hospital University Sains Malaysia (HUSM) from 1984 to 1989 was done. The mean age of the patients was 60.3 years with a high proportion (76.6%) of them were between 41 and 70 years. Seventy five percent of patients (84% of men and 26% of women) were smokers. The Chinese have a significantly higher preponderance to carcinoma of the lung. The commonest histological type found was squamous cell carcinoma in men and adenocarcinoma in women. Small cell carcinoma was uncommon. Squamous cell and large cell/undifferentiated type of carcinoma were significantly associated with smoking behaviour of the patients.
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