Displaying publications 81 - 100 of 149 in total

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  1. Chiong HS, Yong YK, Ahmad Z, Sulaiman MR, Zakaria ZA, Yuen KH, et al.
    Int J Nanomedicine, 2013;8:1245-55.
    PMID: 23569374 DOI: 10.2147/IJN.S42801
    Liposomal drug delivery systems, a promising lipid-based nanoparticle technology, have been known to play significant roles in improving the safety and efficacy of an encapsulated drug.
  2. Ahmad Z, Zamhuri KF, Yaacob A, Siong CH, Selvarajah M, Ismail A, et al.
    Molecules, 2012 Aug 10;17(8):9631-40.
    PMID: 22885359 DOI: 10.3390/molecules17089631
    The amino acid and fatty acid composition of polypeptide k and oil isolated from the seeds of Momordica charantia was analysed. The analysis revealed polypeptide k contained 9 out of 11 essential amino acids, among a total of 18 types of amino acids. Glutamic acid, aspartic acid, arginine and glycine were the most abundant (17.08%, 9.71%, 9.50% and 8.90% of total amino acids, respectively). Fatty acid analysis showed unusually high amounts of C18-0 (stearic acid, 62.31% of total fatty acid). C18-1 (oleic acid) and C18-2 (linoleic acid) were the other major fatty acid detected (12.53% and 10.40%, respectively). The oil was devoid of the short fatty acids (C4-0 to C8-0). Polypeptide k and oil were also subjected to in vitro α-glucosidase and α-amylase inhibition assays. Both polypeptide k and seed oil showed potent inhibition of α-glucosidase enzyme (79.18% and 53.55% inhibition, respectively). α-Amylase was inhibited by 35.58% and 38.02%, respectively. Collectively, the in vitro assay strongly suggests that both polypeptide k and seed oil from Momordica charantia are potent potential hypoglycemic agents.
  3. Mohd Adib MA, Yusof MF, Ahmad Z, Mohd Hasni NH
    J Integr Bioinform, 2012;9(2):195.
    PMID: 22781711 DOI: 10.2390/biecoll-jib-2012-195
    Echocardiogram is an ultrasound image of the heart that demonstrates the size, motion and composition of cardiac structures and is also used to diagnose various abnormalities of the heart including abnormal chamber size, shape and congenital heart disease. Echocardiography provides important morphological and functional details of the heart. Most of the presented automatic cardiac disease recognition systems that use echocardiograms based on defective anatomical region detection. In this paper we present a simple technique for cardiac geometry detection via echocardiogram images which conquer these borders and exploits cues from cardiac structure. To demonstrate the effectiveness of this technique, we present results for cardiac geometry detection through difference intensity of echocardiogram images. We have developed a simple program code for the prediction of cardiac geometry using difference intensity of echocardiogram images. With this code, users can generate node or point for detection of cardiac geometry as ventricle and atrium in size, shape and location.
  4. Ali YM, Kadir AA, Ahmad Z, Yaakub H, Zakaria ZA, Abdullah MN
    Pharm Biol, 2012 Jun;50(6):712-9.
    PMID: 22181061 DOI: 10.3109/13880209.2011.621714
    Conjugated linoleic acids (CLAs) are a mixture of positional and geometric isomers of linoleic acid (LA) and believed to have many positive biological activities.
  5. Somchit N, Chung JH, Yaacob A, Ahmad Z, Zakaria ZA, Kadir AA
    Drug Chem Toxicol, 2012 Jul;35(3):304-9.
    PMID: 22288423 DOI: 10.3109/01480545.2011.614619
    Voriconazole is a new, potent broad-spectrum triazole systemic antifungal drug, a second-generation azole antifungal that is increasing in popularity, especially for the treatment of invasive aspergillosis and fluconazole-resistant invasive Candida infections. However, it is also known to induce hepatotoxicity clinically. The aim of this study was to investigate the hepatotoxicity and nephrotoxicity potential of voriconazole in vivo in rats. Forty rats were treated intraperitoneally with voriconazole as single (0, 10, l00, and 200 mg/kg) or repeated (0, 10, 50, and l00 mg/kg per day for 14 days) doses. Venous blood was collected for the repeated-dose group on days 1 and 14. Rats were sacrificed 24 hours after the last dose. Body weight, liver weight, and kidney weight of rats were recorded. Livers and kidneys samples were taken for histological and transmission electron microscopy (TEM) analysis. Results revealed that voriconazole had no effects on serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphotase, gamma glutamyl transpeptidase, blood urea nitrogen, and creatinine for both the single- and repeated-dose groups. However, histologically, in the repeated 50- and 100-mg/kg voriconazole-treated rats, mild focal inflammation was observed. Under TEM, only small changes in the 100 mg/kg/day group were revealed. These results collectively demonstrated that voriconazole did not induce significant hepatotoxicity and nephrotoxicity, even at very high doses.
  6. Dahlan I, Ahmad Z, Fadly M, Lee KT, Kamaruddin AH, Mohamed AR
    J Hazard Mater, 2010 Jun 15;178(1-3):249-57.
    PMID: 20137857 DOI: 10.1016/j.jhazmat.2010.01.070
    In this work, the application of response surface and neural network models in predicting and optimizing the preparation variables of RHA/CaO/CeO(2) sorbent towards SO(2)/NO sorption capacity was investigated. The sorbents were prepared according to central composite design (CCD) with four independent variables (i.e. hydration period, RHA/CaO ratio, CeO(2) loading and the use of RHA(raw) or pretreated RHA(600 degrees C) as the starting material). Among all the variables studied, the amount of CeO(2) loading had the largest effect. The response surface models developed from CCD was effective in providing a highly accurate prediction for SO(2) and NO sorption capacities within the range of the sorbent preparation variables studied. The prediction of CCD experiment was verified by neural network models which gave almost similar results to those determined by response surface models. The response surface models together with neural network models were then successfully used to locate and validate the optimum hydration process variables for maximizing the SO(2)/NO sorption capacities. Through this optimization process, it was found that maximum SO(2) and NO sorption capacities of 44.34 and 3.51 mg/g, respectively could be obtained by using RHA/CaO/CeO(2) sorbents prepared from RHA(raw) with hydration period of 12h, RHA/CaO ratio of 2.33 and CeO(2) loading of 8.95%.
  7. Rahman AA, Sulaiman SA, Ahmad Z, Salleh H, Daud WN, Hamid AM
    PMID: 19323019
    The objective of this cross-sectional study was to determine whether the use of herbal medicines during pregnancy is associated with women's attitudes towards herbal medicines and their sociodemographic features, such as age, education level, and income. Two-hundred ten women (110 "users," 100 "non-users") were studied. The probability of using herbal medicines among women who had negative attitudes towards the use of herbal medicines was 50.0% less compared to those who had positive attitudes (OR = 0.51, 95% CI = 0.29 - 0.92). Women who had a positive attitude towards the safety of herbal medicines were less likely to use herbal medicines during pregnancy. There were no significant associations between usage and sociodemographic features, such as age, income, race, and education.
  8. Low CF, Chong PP, Yong PV, Lim CS, Ahmad Z, Othman F
    J Appl Microbiol, 2008 Dec;105(6):2169-77.
    PMID: 19120662 DOI: 10.1111/j.1365-2672.2008.03912.x
    The aims of the present study were to determine whether Allium sativum (garlic) extract has any effect on the morphology transformation of Candida albicans, and to investigate whether it could alter the gene expression level of SIR2, a morphogenetic control gene and SAP4, a gene encoding secreted aspartyl proteinase.
  9. Soh KL, Soh KG, Ahmad Z, Abdul Raman R, Japar S
    Contemp Nurse, 2008 Dec;31(1):86-93.
    PMID: 19117504
    The Intensive Care Unit (ICU) is a therapeutic place for monitoring critically ill patients. However, it is a stressful area for the patients and it is causing them great anxiety. Previous studies have identified three groups of stressors in ICU namely; physical, psychological and environmental. The aims of this study were to determine the ICU stressors as experienced by patients and to determine the level of stressors felt by patients in ICU. A cross sectional study was done on 70 patients from two tertiary hospitals in Malaysia. A face-to-face interview with structured questionnaire was used for patients. Data collection occurred from 15 December 2006 to 31 January 2007. The five major ICU stressors perceived by patients were pain, being stuck with needles, boredom, missing their spouses and being too hot/cold. The ICU physical stressors were the major items ranked by post ICU patients. The findings from this study provided a set of baseline information to the health care providers, particularly ICU nurses in Malaysia, with which to provide better care for the patients in ICU.
  10. Ab Rahman A, Ahmad Z, Naing L, Sulaiman SA, Hamid AM, Daud WN
    PMID: 18613559
    The objective of this case-control study was to determine the association between herbal medicine use during pregnancy and perinatal mortality in Tumpat District, Kelantan, Malaysia. Cases were mothers who gave birth from June 2002 to June 2005 with a history of perinatal mortality, while controls were those without a history of perinatal infant mortality. A total of 316 mothers (106 cases and 210 controls) were interviewed. The use of unidentified herbs prepared by traditional midwives and other types of herbal medicines during the first trimester of pregnancy were positively associated with perinatal mortality (OR = 5.24, 95% CI = 1.13; 24.23 and OR = 8.90, 95%, CI = 1.35; 58.53, respectively). The use of unidentified "Orang Asli" herbs and coconut oil during the third trimester of pregnancy were negatively associated with perinatal mortality in Tumpat (OR = 0.10, 95% CI = 0.02; 0.59 and OR = 0.48, 95% CI = 0.25; 0.92, respectively). These findings suggest the use of unidentified "Orang Asli" herbs and coconut oil in late pregnancy are protective against perinatal mortality, while the use of unidentified herbs prepared by traditional midwives and other types of herbal medicines in early pregnancy has an increased risk of perinatal infant mortality. Pharmacological studies to confirm and identify the compounds in these herbs and their effects on the fetus should be conducted in the future.
  11. Dorniani D, Hussein MZ, Kura AU, Fakurazi S, Shaari AH, Ahmad Z
    Int J Nanomedicine, 2012;7:5745-56.
    PMID: 23166439 DOI: 10.2147/IJN.S35746
    Magnetic iron oxide nanoparticles were prepared using a sonochemical method under atmospheric conditions at a Fe²⁺ to Fe³⁺ molar ratio of 1:2. The iron oxide nanoparticles were subsequently coated with chitosan and gallic acid to produce a core-shell structure.
  12. Teh SS, Ee GC, Mah SH, Lim YM, Ahmad Z
    Molecules, 2013 Feb 04;18(2):1985-94.
    PMID: 23381024 DOI: 10.3390/molecules18021985
    The cytotoxic structure-activity relationships among a series of xanthone derivatives from Mesua beccariana, Mesua ferrea and Mesua congestiflora were studied. Eleven xanthone derivatives identified as mesuarianone (1), mesuasinone (2), mesuaferrin A (3), mesuaferrin B (4), mesuaferrin C (5), 6-deoxyjacareubin (6), caloxanthone C (7), macluraxanthone (8), 1,5-dihydroxyxanthone (9), tovopyrifolin C (10) and α-mangostin (11) were isolated from the three Mesua species. The human cancer cell lines tested were Raji, SNU-1, K562, LS-174T, SK-MEL-28, IMR-32, HeLa, Hep G2 and NCI-H23. Mesuaferrin A (3), macluraxanthone (8) and α-mangostin (11) showed strong cytotoxicities as they possess significant inhibitory effects against all the cell lines. The structure-activity relationship (SAR) study revealed that the diprenyl, dipyrano and prenylated pyrano substituent groups of the xanthone derivatives contributed towards the cytotoxicities.
  13. Hasali MA, Ibrahim MI, Sulaiman SA, Ahmad Z, Hasali JB
    Pharm World Sci, 2005 Jun;27(3):249-53.
    PMID: 16096896
    BACKGROUND: Pneumonia is one of the leading causes of morbidity and mortality among children in many developing countries. It is reported that 12.9 million children under 5 years of age died world-wide in 1990 and one-third of these deaths or 4.3 million annually were attributed to acute respiratory infection with pneumonia.

    OBJECTIVES: On this basis, a study was conducted in a district hospital to study the therapy outcomes of antibiotic regimens used in pediatric community-acquired pneumonia (CAP) management and to conduct a cost-effectiveness analysis (CE) between IV ampicillin versus combination therapy of IV ampicillin and IV gentamicin.

    METHOD: A prospective, randomized, controlled, single blind study was conducted in a pediatric ward in a 80-bed district hospital. Pediatric patients diagnosed with CAP aged 2 months to 5 years old were randomly and equally divided into two treatment arms: ampicillin versus ampicillin plus gentamicin. The dose of IV ampicillin used in this study was 100 mg/kg/day divided every 6 h and 5 mg/kg of IV gentamicin as a single daily dose. Both clinical and economic evaluations were carried out to compare both treatment arms.

    RESULTS: With the inclusion and exclusion criteria, only 40 patients diagnosed with CAP were included in the study. The results showed that the two treatment arms were significantly different (P < 0.05) in terms of duration of patients on ampicillin, number of days of hospitalization and time to switch to oral therapy. A significant difference was noted between the two treatment modalities in terms of effectiveness and cost (P < 0.05).

    CONCLUSION: Overall, the endpoint of this study showed that the total cost per patient of ampicillin-treated group is cheaper than the total cost with the combination therapy (ampicillin plus gentamicin) and reduced unnecessary exposure to adverse effects or toxicities. Besides that, addition of gentamicin in the treatment modalities will only increase the cost of treatment without introducing any changes in the treatment outcome.

  14. Ullah F, Othman MB, Javed F, Ahmad Z, Md Akil H
    Mater Sci Eng C Mater Biol Appl, 2015 Dec 1;57:414-33.
    PMID: 26354282 DOI: 10.1016/j.msec.2015.07.053
    This article aims to review the literature concerning the choice of selectivity for hydrogels based on classification, application and processing. Super porous hydrogels (SPHs) and superabsorbent polymers (SAPs) represent an innovative category of recent generation highlighted as an ideal mould system for the study of solution-dependent phenomena. Hydrogels, also termed as smart and/or hungry networks, are currently subject of considerable scientific research due to their potential in hi-tech applications in the biomedical, pharmaceutical, biotechnology, bioseparation, biosensor, agriculture, oil recovery and cosmetics fields. Smart hydrogels display a significant physiochemical change in response to small changes in the surroundings. However, such changes are reversible; therefore, the hydrogels are capable of returning to its initial state after a reaction as soon as the trigger is removed.
  15. Othman MB, Khan A, Ahmad Z, Zakaria MR, Ullah F, Akil HM
    Carbohydr Polym, 2016 Jan 20;136:1182-93.
    PMID: 26572461 DOI: 10.1016/j.carbpol.2015.10.034
    This study attempted to clarify the influence of a cross-linker, N,N-methylenebisacrylamide (MBA), and N-isopropylacrylamide (NIPAM) on the non-isothermal kinetic degradation, solid state and lifetime of hydrogels using the Flynn-Wall-Ozawa (F-W-O), Kissinger, and Coats-Redfern (C-Red) methods. The series of dual-responsive Cs-PNIPAM-MBA microgels were synthesized by soapless-emulsion free radical copolymerization in an aqueous medium at 70 °C. The thermal properties were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) under nitrogen atmosphere. The apparent activation energy using the chosen Flynn-Wall-Ozawa and Kissinger methods showed that they fitted each other. Meanwhile, the type of solid state mechanism was determined using the Coats-Redfern method proposed for F1 (pure Cs) and F2 (Cs-PNIPAM-MBA hydrogel series) types, which comprise random nucleation with one nucleus reacting on individual particles, and random nucleation with two nuclei reacting on individual particles, respectively. On average, a higher Ea was attributed to the greater cross-linking density of the Cs hydrogel.
  16. Fong LY, Ng CT, Cheok ZL, Mohd Moklas MA, Hakim MN, Ahmad Z
    Phytomedicine, 2016 Feb 15;23(2):191-9.
    PMID: 26926181 DOI: 10.1016/j.phymed.2015.11.019
    Endothelial cell activation is characterized by increased endothelial permeability and increased expression of cell adhesion molecules (CAMs). This allows monocyte adherence and migration across the endothelium to occur and thereby initiates atherogenesis process. Asiatic acid is a major triterpene isolated from Centella asiatica (L.) Urban and has been shown to possess anti-oxidant, anti-hyperlipidemia and anti-inflammatory activities.
  17. Omar M, Ali HM, Abu MP, Kontol KM, Ahmad Z, Ahmad SH, et al.
    Appl Radiat Isot, 2004 May;60(5):779-82.
    PMID: 15082059
    Radium concentrations in 470 samples of the various types of waste from oil and gas industries were analysed using gamma spectrometers. The results showed that the radium concentration varied within a wide range. The highest mean 226Ra and 228Ra concentrations of 114,300 and 130,120 Bq/kg, respectively, were measured in scales. Overall, 75% of the waste, mostly sludge and extraction residue lies within the normal range of radium concentration in soils of Malaysia. However, some platform sludge can have radium concentration up to 560 Bq/kg.
  18. Chow ZP, Ahmad Z, Wong KJ, Koloor SSR, Petrů M
    Polymers (Basel), 2021 Feb 04;13(4).
    PMID: 33557350 DOI: 10.3390/polym13040492
    This paper aims to propose a temperature-dependent cohesive model to predict the delamination of dissimilar metal-composite material hybrid under Mode-I and Mode-II delamination. Commercial nonlinear finite element (FE) code LS-DYNA was used to simulate the material and cohesive model of hybrid aluminium-glass fibre-reinforced polymer (GFRP) laminate. For an accurate representation of the Mode-I and Mode-II delamination between aluminium and GFRP laminates, cohesive zone modelling with bilinear traction separation law was implemented. Cohesive zone properties at different temperatures were obtained by applying trends of experimental results from double cantilever beam and end notched flexural tests. Results from experimental tests were compared with simulation results at 30, 70 and 110 °C to verify the validity of the model. Mode-I and Mode-II FE models compared to experimental tests show a good correlation of 5.73% and 7.26% discrepancy, respectively. Crack front stress distribution at 30 °C is characterised by a smooth gradual decrease in Mode-I stress from the centre to the edge of the specimen. At 70 °C, the entire crack front reaches the maximum Mode-I stress with the exception of much lower stress build-up at the specimen's edge. On the other hand, the Mode-II stress increases progressively from the centre to the edge at 30 °C. At 70 °C, uniform low stress is built up along the crack front with the exception of significantly higher stress concentrated only at the free edge. At 110 °C, the stress distribution for both modes transforms back to the similar profile, as observed in the 30 °C case.
  19. Leong SS, Ahmad Z, Low SC, Camacho J, Faraudo J, Lim J
    Langmuir, 2020 07 21;36(28):8033-8055.
    PMID: 32551702 DOI: 10.1021/acs.langmuir.0c00839
    The migration process of magnetic nanoparticles and colloids in solution under the influence of magnetic field gradients, which is also known as magnetophoresis, is an essential step in the separation technology used in various biomedical and engineering applications. Many works have demonstrated that in specific situations, separation can be performed easily with the weak magnetic field gradients created by permanent magnets, a process known as low-gradient magnetic separation (LGMS). Due to the level of complexity involved, it is not possible to understand the observed kinetics of LGMS within the classical view of magnetophoresis. Our experimental and theoretical investigations in the last years unravelled the existence of two novel physical effects that speed up the magnetophoresis kinetics and explain the observed feasibility of LGMS. Those two effects are (i) cooperative magnetophoresis (due to the cooperative motion of strongly interacting particles) and (ii) magnetophoresis-induced convection (fluid dynamics instability originating from inhomogeneous magnetic gradients). In this feature article, we present a unified view of magnetophoresis based on the extensive research done on these effects. We present the physical basis of each effect and also propose a classification of magnetophoresis into four distinct regimes. This classification is based on the range of values of two dimensionless quantities, namely, aggregation parameter N* and magnetic Grashof number Grm, which include all of the dependency of LGMS on various physical parameters (such as particle properties, thermodynamic parameters, fluid properties, and magnetic field properties). This analysis provides a holistic view of the classification of transport mechanisms in LGMS, which could be particularly useful in the design of magnetic separators for engineering applications.
  20. Ahmad Z, Jaafar R, Mohd Hassan MH, Othman MS, Hashim A
    Malays J Nutr, 1997 Mar;3(1):83-90.
    PMID: 22692237 MyJurnal
    A retrospective study of anaemia in pregnancy in rural Kelantan was conducted. The study sample consist of 9,860 mothers who had antenatal care at one of the 102 rural health clinics selected and had delivered a live baby. Anaemia in pregnancy was determined by reviewing the antenatal records for the haemoglobin level recorded at the first and last antenatal visit. Estimation of haemoglobin was done either by photocalorimetric methods or the Sahli's method in these rural clinics. At the time of booking, 47.5% of the mothers were anaemic by WHO criteria (Hb < 11.0 g/dl), with 1.9% having less than 9.0 g/dl. Age of mother, parity and late gestational age at the first antenatal visit were associated with anaemia during pregnancy at the time of booking. However, practise of contraception by the mother did not show any association with anaemia in pregnancy. There were 594 mothers (6.0%) who delivered a baby weighing less than 2.5 kg. There was no association between the low birth weight of the child and the status of anaemia in the mother at the last antenatal visit.
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