Displaying publications 281 - 300 of 663 in total

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  1. Ahmed HMA, Luddin N, Kannan TP, Mokhtar KI, Ahmad A
    Restor Dent Endod, 2017 Aug;42(3):176-187.
    PMID: 28808634 DOI: 10.5395/rde.2017.42.3.176
    OBJECTIVES: This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate (CaCl2·2H2O), compared to that of WMTA.

    MATERIALS AND METHODS: Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazol-diphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively.

    RESULTS: Results showed that the addition of CaCl2·2H2O to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA.

    CONCLUSIONS: The addition of CaCl2·2H2O to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects.

  2. Afzal S, Batool M, Ch BA, Ahmad A, Uzair M, Afzal K
    Pharmacogn Mag, 2017 Jul;13(Suppl 2):S262-S265.
    PMID: 28808390 DOI: 10.4103/pm.pm_398_16
    AIMS: The study is conducted to evaluate the immunomodulatory, cytotoxicity, and antioxidant potential of Ziziphus mauritiana (Rhamnaceae). Phytochemical analysis of Z. mauritiana revealed the presence of alkaloids, anthraquinone glycoside, cardiac glycoside, saponin, tannin, and flavonoids.

    METHODOLOGY: The cytotoxicity of the plant Z. mauritiana was evaluated by brine shrimp lethality test. Antioxidant parameters such as superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and malondialdehyde (MDA) levels were calculated in the plasma of rats after chronic administration of 400 mg/kg of Z. mauritiana for 6 weeks.

    RESULTS: The dichloromethane extract of the plant exhibited significant immunomodulatory activity, with inhibitory concentration 50% of 55.43 ± 7.9. The dichloromethane extracts of the plant showed 70% mortality at concentration 1000 μg/ml. SOD and T-AOC levels were increased while MDA level in the plasma was reduced in the plasma of rats treated with dichloromethane Z. mauritiana.

    CONCLUSION: This can be deduced that the root of Z. mauritiana has immunomodulatory, cytotoxic, and antioxidant potential.

    SUMMARY: Roots of Z. mauritiana was exhibited immunomodulator, cytotoxic and antioxidant activitiesZ. mauritiana showed potential antioxidant activity in rats Abbreviations used: SOD: Superoxide dismutase; T-AOC: Total antioxidant capacity; MDA: Malondialdehyde; ZMRD: Z. mauritiana root extract of dichloromethane fraction; LD50: Z. mauritiana root extract of methanol fraction ZMRM, lethal dose 50.

  3. Patel I, Hussain R, Khan A, Ahmad A, Khan MU, Hassalai MAA
    PMID: 28878929 DOI: 10.1186/s40545-017-0118-6
  4. Aziz ZABA, Ahmad A, Mohd-Setapar SH, Hassan H, Lokhat D, Kamal MA, et al.
    Curr Drug Metab, 2017;18(1):16-29.
    PMID: 27654898 DOI: 10.2174/1389200217666160921143616
    In clinical studies, drugs with hydrophobic characteristic usually reflect low bioavailability, poor drug absorption, and inability to achieve the therapeutic concentration in blood. The production of poor solubility drugs, in abundance, by pharmaceutical industries calls for an urgent need to find the alternatives for resolving the above mentioned shortcomings. Poor water solubility drugs loaded with polymeric micelle seem to be the best alternative to enhance drugs solubility and bioavailability. Polymeric micelle, formed by self-assembled of amphiphilic block copolymers in aqueous environment, functioned as solubilizing agent for hydrophobic drug. This review discusses the fundamentals of polymeric micelle as drug carrier through representative literature, and demonstrates some applications in various clinical trials. The structure, characteristic, and formation of polymeric micelle have been discussed firstly. Next, this manuscript focuses on the potential of polymeric micelles as drug vehicle in oral, transdermal routes, and anti-cancer agent. Several results from previous studies have been reproduced in this review in order to prove the efficacy of the micelles in delivering hydrophobic drugs. Lastly, future strategies to broaden the application of polymeric micelles in pharmaceutical industries have been highlighted.
  5. Abu Sepian NR, Mat Yasin NH, Zainol N, Rushan NH, Ahmad AL
    Environ Technol, 2019 Apr;40(9):1110-1117.
    PMID: 29161985 DOI: 10.1080/09593330.2017.1408691
    The immobilisation of Chlorella vulgaris 211/11B entrapped in combinations of natural matrices to simplify the harvesting process was demonstrated in this study. Three combinations of matrices composed of calcium alginate (CA) and sodium alginate (SA), sodium carboxymethyl cellulose (CMC) and SA, and mixed matrices (SA, CA, and CMC) were investigated. The number of cells grown for each immobilised matrix to microalgae volume ratios (0.2:1-1:1) were explored and compared with using SA solely as a control. The optimum volume ratios obtained were 1:1 for SA, 0.3:1 for CA and SA, 1:1 for CMC and SA, and 0.3:1 for mixed matrices. The immobilised microalgae of mixed matrices exhibited the highest number of cells with 1.72 × 109 cells/mL at day 10 and 30.43% of oil extraction yield followed by CA and SA (24.29%), CMC and SA (13.00%), and SA (6.71%). Combining SA, CA, and CMC had formed a suitable structure which improved the growth of C. vulgaris and increased the lipid production compared to the immobilisation using single matrix. Besides, the fatty acids profile of the oil extracted indicates a high potential for biodiesel production.
  6. Iqbal Z, Bello I, Asmawi MZ, Al-Mansoub MA, Ahmad A, Jabeen Q, et al.
    Inflammopharmacology, 2019 Apr;27(2):421-431.
    PMID: 29185178 DOI: 10.1007/s10787-017-0422-4
    Previous studies have investigated the cardiovascular activity of Gynura procumbens Merr. single-solvent extracts. The objective of this study was to evaluate the in vitro vasorelaxant properties and the underlying pharmacological mechanisms of serial extracts and fractions of Gynura procumbens (GP). The leaves of GP were serially extracted with petroleum ether, chloroform, methanol and water using the maceration method. Suspended aortic ring preparations were pre-contracted with phenylephrine (PE 1 µM), followed by cumulative addition of GP extracts (0.25-3 mg/mL). The petroleum ether extract (GPPE) was the most potent among the four extracts. Pre-incubation of endothelium-intact aorta with atropine (1 µM), indomethacin (10 µM), methylene blue (10 µM), propranolol (1 µM) and potassium channel blockers such as TEA (1 µM), glibenclamide (10 µM), 4-aminopyridine (1 µM) and barium chloride (10 mM) had no effect on GPPE-induced vasorelaxation. The vasorelaxant effect of GPPE was partly diminished by pretreatment of aortic rings preparations with L-NAME (10 µM) and even more so in endothelium-denuded aortic rings, indicating a minimal involvement of endothelium-dependent pathway in GPPE-induced vasorelaxation. The calcium-induced vasocontractions were antagonized significantly and concentration-dependently by GPPE in calcium free and high potassium medium. These results illustrate that Ca2+ antagonizing actions of GPPE in rat isolated aorta are comparable to that of verapamil and may be mainly responsible for its vasodilation effect. The antioxidant activity of GPPE supports its vasorelaxant effect by attenuating the production of deleterious free radicals and reactive oxygen species in the vasculature.
  7. Ariffin EY, Lee YH, Futra D, Tan LL, Karim NHA, Ibrahim NNN, et al.
    Anal Bioanal Chem, 2018 Mar;410(9):2363-2375.
    PMID: 29504083 DOI: 10.1007/s00216-018-0893-1
    A novel electrochemical DNA biosensor for ultrasensitive and selective quantitation of Escherichia coli DNA based on aminated hollow silica spheres (HSiSs) has been successfully developed. The HSiSs were synthesized with facile sonication and heating techniques. The HSiSs have an inner and an outer surface for DNA immobilization sites after they have been functionalized with 3-aminopropyltriethoxysilane. From field emission scanning electron microscopy images, the presence of pores was confirmed in the functionalized HSiSs. Furthermore, Brunauer-Emmett-Teller (BET) analysis indicated that the HSiSs have four times more surface area than silica spheres that have no pores. These aminated HSiSs were deposited onto a screen-printed carbon paste electrode containing a layer of gold nanoparticles (AuNPs) to form a AuNP/HSiS hybrid sensor membrane matrix. Aminated DNA probes were grafted onto the AuNP/HSiS-modified screen-printed electrode via imine covalent bonds with use of glutaraldehyde cross-linker. The DNA hybridization reaction was studied by differential pulse voltammetry using an anthraquinone redox intercalator as the electroactive DNA hybridization label. The DNA biosensor demonstrated a linear response over a wide target sequence concentration range of 1.0×10-12-1.0×10-2 μM, with a low detection limit of 8.17×10-14 μM (R2 = 0.99). The improved performance of the DNA biosensor appeared to be due to the hollow structure and rough surface morphology of the hollow silica particles, which greatly increased the total binding surface area for high DNA loading capacity. The HSiSs also facilitated molecule diffusion through the silica hollow structure, and substantially improved the overall DNA hybridization assay. Graphical abstract Step-by-step DNA biosensor fabrication based on aminated hollow silica spheres.
  8. Ahmad A, Sattar MA, Azam M, Khan SA, Bhatt O, Johns EJ
    PLoS One, 2018;13(2):e0189386.
    PMID: 29447158 DOI: 10.1371/journal.pone.0189386
    Left ventricular hypertrophy (LVH) is associated with decreased responsiveness of renal α1-adrenoreceptors subtypes to adrenergic agonists. Nitric oxide donors are known to have antihypertrophic effects however their impact on responsiveness of renal α1-adrenoreceptors subtypes is unknown. This study investigated the impact of nitric oxide (NO) and its potential interaction with the responsiveness of renal α1-adrenoreceptors subtypes to adrenergic stimulation in rats with left ventricular hypertrophy (LVH). This study also explored the impact of NO donor on CSE expression in normal and LVH kidney. LVH was induced using isoprenaline and caffeine in drinking water for 2 weeks while NO donor (L-arginine, 1.25g/Lin drinking water) was given for 5 weeks. Intrarenal noradrenaline, phenylephrine and methoxamine responses were determined in the absence and presence of selective α1-adrenoceptor antagonists, 5- methylurapidil (5-MeU), chloroethylclonidine (CeC) and BMY 7378. Renal cortical endothelial nitric oxide synthase mRNA was upregulated 7 fold while that of cystathione γ lyase was unaltered in the NO treated LVH rats (LVH-NO) group compared to LVH group. The responsiveness of renal α1A, α1B and α1D-adrenoceptors in the low dose and high dose phases of 5-MeU, CEC and BMY7378 to adrenergic agonists was increased along with cGMP in the kidney of LVH-NO group. These findings suggest that exogenous NO precursor up-regulated the renal eNOS/NO/cGMP pathway in LVH rats and resulted in augmented α1A, α1B and α1D adrenoreceptors responsiveness to the adrenergic agonists. There is a positive interaction between H2S and NO production in normal animals but this interaction appears absent in LVH animals.
  9. Eseyin OA, Sattar MA, Rathore HA, Aigbe F, Afzal S, Ahmad A, et al.
    Pak J Pharm Sci, 2018 Jan;31(1):45-50.
    PMID: 29348083
    Telfairia occidentalis possesses high antioxidant activity. However, the antioxidant components of the plant have not yet been identified. This study was undertaken to identify the phenolics in the leaf of the plant. Extract and fractions of the leaf of the plant were analysed using the HPLC and GCMS. HPLC analysis revealed the presence of gallic acid (22.19μg/mg), catechin (29.17μg/mg), caffeic acid (9.17μg/mg), ferulic acid (0.94μg/mg), sinapic acid (1.91 μg/mg) and 4-hydroxy benzoic acid (43.86 μg/mg) in the aqueous extract. Phenolics fraction contained gallic acid (0.88 μg/mg), catechin (2.70μg/mg), caffeic acid (7.92μg/mg), ferulic acid (2.72μg/mg), benzoic acid (6.36μg/mg), p-coumaric acid (1.48μg/mg), quercetin (12.00μg/mg). Only caffeic acid (2.50μg/mg), ferulic acid (0.44μg/mg) and quercetin (8.50μg/mg) were detected in the flavonoid fraction. While GCMS analysis showed the presence of methylparaben; ethylparaben; benzoic acid; 4-hydroxy-2-methoxy-3,5,6-trimethyl-, methyl ester; 4-hydroxy-3-methoxy; phenol, 5-methoxy-2-(methoxymethyl)-; phenol, 5-methoxy-2, 3- dimethyl; and phenol, 2-(2-benzothiazolyl)-. This study is the first to reveal the identity of some phenolics components of the leaf of Telfairia occidentalis.
  10. Ali SG, Jalal M, Ahmad H, Umar K, Ahmad A, Alshammari MB, et al.
    Molecules, 2022 Dec 08;27(24).
    PMID: 36557818 DOI: 10.3390/molecules27248685
    Antimicrobial resistance has posed a serious health concern worldwide, which is mainly due to the excessive use of antibiotics. In this study, gold nanoparticles synthesized from the plant Tinospora cordifolia were used against multidrug-resistant Pseudomonas aeruginosa. The active components involved in the reduction and stabilization of gold nanoparticles were revealed by gas chromatography-mass spectrophotometry(GC-MS) of the stem extract of Tinospora cordifolia. Gold nanoparticles (TG-AuNPs) were effective against P. aeruginosa at different concentrations (50,100, and 150 µg/mL). TG-AuNPs effectively reduced the pyocyanin level by 63.1% in PAO1 and by 68.7% in clinical isolates at 150 µg/mL; similarly, swarming and swimming motilities decreased by 53.1% and 53.8% for PAO1 and 66.6% and 52.8% in clinical isolates, respectively. Biofilm production was also reduced, and at a maximum concentration of 150 µg/mL of TG-AuNPs a 59.09% reduction inPAO1 and 64.7% reduction in clinical isolates were observed. Lower concentrations of TG-AuNPs (100 and 50 µg/mL) also reduced the pyocyanin, biofilm, swarming, and swimming. Phenotypically, the downregulation of exopolysaccharide secretion from P. aeruginosa due to TG-AuNPs was observed on Congo red agar plates.
  11. Mamat R, Rashid RA, Sim MS, Ibrahim B, Wahab S, Ahmad A
    J Psychoactive Drugs, 2023 Mar 20.
    PMID: 36940284 DOI: 10.1080/02791072.2023.2190331
    ATS dependence in Malaysia is growing tremendously across multiracial Malaysian groups, increasing concerns among public health experts and the community. This study highlighted the chronicity of ATS dependence and factors associated with ATS use. Interviewer-administered questionnaires were administered using ASSIST 3.0. A total of N = 327 multiracial people who use ATS were enrolled in this study. The study findings show that 190/327 (58.1%) respondents were ATS dependent. Malays reported the highest number of ATS-dependent (55.8%), followed by Bajau (21.6%) and Kadazan-Dusun (16.8%) ethnic. Across all races, three factors were significantly associated with the ATS dependence: respondents who had a lifetime history of needle sharing aOR = 0.023 (95% CI: 0.003, 0.183) and a lifetime history of heroin use aOR = 0.192 (95% CI: 0.093, 0.396) were at a reduced odd of ATS dependent. Meanwhile, being married reduced the likelihood of becoming dependent on ATS with aOR = 0.378 (95% CI: 0.206, 0.693) compared to being single or divorced. This study revealed that the use of ATS among multiracial Malaysians is alarmingly high, including those in detention centers. Comprehensive harm reduction strategies are urgently needed to prevent the spreading of infectious diseases and other negative health consequences associated with ATS use.
  12. Reddy AVB, Rafiq R, Ahmad A, Maulud AS, Moniruzzaman M
    Molecules, 2022 Nov 11;27(22).
    PMID: 36431876 DOI: 10.3390/molecules27227775
    In the current study, we have synthesized an imidazolium based cross-linked polymer, namely, 1-vinyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide (poly[veim][Tf2N]-TRIM) using trimethylolpropane trimethacrylate as cross linker, and demonstrated its efficiency for the removal of two extensively used ionic dyes—methylene blue and orange-II—from aqueous systems. The detailed characterization of the synthesized poly[veim][Tf2N]-TRIM was performed with the help of 1H NMR, TGA, FT-IR and FE-SEM analysis. The concentration of dyes in aqueous samples before and after the adsorption process was measured using an UV-vis spectrophotometer. The process parameters were optimised, and highest adsorption was obtained at a solution pH of 7.0, adsorbent dosage of 0.75 g/L, contact time of 7 h and dye concentrations of 100 mg/L and 5.0 mg/L for methylene blue and orange-II, respectively. The adsorption kinetics for orange-II and methylene blue were well described by pseudo-first-order and pseudo−second-order models, respectively. Meanwhile, the process of adsorption was best depicted by Langmuir isotherms for both the dyes. The highest monolayer adsorption capacities for methylene blue and orange-II were found to be 1212 mg/g and 126 mg/g, respectively. Overall, the synthesized cross-linked poly[veim][Tf2N]-TRIM effectively removed the selected ionic dyes from aqueous samples and provided >90% of adsorption efficiency after four cycles of adsorption. A possible adsorption mechanism between the synthesised polymeric adsorbent and proposed dyes is presented. It is further suggested that the proposed ionic liquid polymer adsorbent could effectively remove other ionic dyes and pollutants from contaminated aqueous systems.
  13. Kura Shehu I, Ahmad HB, Kayode Olayemi I, Solomon D, Hassan Ahmad A, Salim H
    Saudi J Biol Sci, 2023 Feb;30(2):103524.
    PMID: 36660609 DOI: 10.1016/j.sjbs.2022.103524
    High resistance ability on insecticides among major mosquito vectors of diseases in Nigeria is of growing concern for severe control strategies. The objective of this study was to assess the susceptibility status of females Anopheles gambiae and Culex quinquefasciatus complexes mosquitoes to permethrin (21.5 μg/bottle-pyrethroids), propoxur(12.5 μg/bottle-carbamate) and malathion (50 μg/bottle organophosphate), in Niger State, North-Central, Nigeria. Anopheline and Culecine larvae were collected from the larval habitats of the studied sites (Bosso, Katcha, Lapai, and Shiroro) larvae and pupae were identified guided by standard keys and reared to adults in troughs. Insecticide susceptibility bioassays were performed according to the CDC bottle bioassay standard operating procedures on 3 days old, sugar-fed female Anopheles and Culex mosquitoes. Post-exposure mortality after 24hr and knockdown values for KDT50 were calculated. Knock-down at 1-hour insecticide exposure ranged (84-96 %) permethrin, (94-100 %) propoxur and (100 %) malathion for An. gambiae and (86-97 %) permethrin, (92-100 %) propoxur and (96-100 %) malathion for Cx. quinquefasciatus. Mortality, after 24hr post-exposure was 100 % in malathion, indicating the high effect of the insecticide. Tested samples were found potentially resistant to permethrin recorded against mosquitoes collected from all study sites, in two locations of the study sites to propoxur and one location site to malathion. All the tested mosquitoes were found to be potentially resistant to permethrin, however, mosquitoes tested in Katcha and Shiroro resist potentially to propoxur. Except, Culex quinqufasciatus from Lapai that partially resist malathion, all the tested mosquitoes were found to be susceptible to malathion, across the study sites.
  14. Geeta A, Jamaiyah H, Safiza MN, Khor GL, Kee CC, Ahmad AZ, et al.
    Singapore Med J, 2009 Oct;50(10):1013-8.
    PMID: 19907894
    INTRODUCTION: The Third National Health and Morbidity Survey Malaysia 2006 includes a nutritional status assessment of children. This study aimed to assess the inter- and intra-examiner reliability, the technical error of measurement and the validity of instruments for measuring weight, height and waist circumference.
    METHODS: A convenience sample of 130 adults working in a selected office setting was chosen to participate in the study, subject to the inclusion and exclusion study criteria. Two public health nurses, trained to follow a standard protocol, obtained the weight, height and waist circumference measurements. The weight was measured using the Tanita HD-318 digital weighing scale to the nearest 0.1 kg, and Seca Beam Scale to the nearest 0.01 kg. The height was measured using the Seca Bodymeter 206 and Stadiometer, both to the nearest 0.1 cm. The waist circumference was measured using the Seca circumference measuring tape S 201, to the nearest 0.1 cm.
    RESULTS: The intra-examiner reliability in descending order was weight and height followed by waist circumference. The height measurement, on average, using the test instrument, reported a recording of 0.4 cm higher than the reference instrument, with the upper and lower limits at 2.5 cm and 1.6 cm, respectively. The technical error of measurement and coefficient of variation of weight and height for both inter-examiner and intra-examiner measurements were all within acceptable limits (below five percent).
    CONCLUSION: The findings of this study suggest that weight, height and waist circumference measured in adults aged 18 years and above, using the respective above mentioned instruments, are reliable and valid for use in a community survey. Limiting the number of examiners, especially for waist circumference measurements, would yield a higher degree of reliability and validity.
  15. Yusof NM, Rahman JA, Zulkifly AH, Che-Ahmad A, Khalid KA, Sulong AF, et al.
    Singapore Med J, 2015 Nov;56(11):626-31.
    PMID: 26668408 DOI: 10.11622/smedj.2015172
    Introduction: Diabetes mellitus (DM) is the most common cause of amputations in Malaysia. This study aimed to identify the predictive factors for major lower limb amputation among patients with type 2 DM (T2DM) who were admitted to a hospital, in order to reduce its likelihood.
    Methods: This cross-sectional study involved 218 patients with T2DM who were admitted to Hospital Tengku Ampuan Afzan, Kuantan, Malaysia, for diabetic foot problems from June 2011 to July 2012. A form was developed to document the patients' profiles, comorbidities, complications, investigations, treatment and clinical outcomes. The predictors for major lower limb amputations were determined using univariate and stepwise logistic regression analysis.
    Results: A total of 31 patients underwent major lower limb amputations (25 transtibial, 6 transfemoral). The following factors were found to be associated with the incidence of major lower limb amputations: T2DM duration ≥ 10 years, diabetic neuropathy, diabetic nephropathy, presentation with gangrene, diabetic foot conditions of Wagner grade 4 or 5, and necrotising fasciitis. Patients who underwent major amputations had significantly lower haemoglobin and albumin levels, and higher total white blood cell counts, erythrocyte sedimentation rates, and C-reactive protein, urea and creatinine levels. However, only T2DM duration ≥ 10 years, positive bacterial culture and albumin levels were significant on stepwise logistic regression analysis.
    Conclusion: T2DM duration ≥ 10 years, positive bacterial culture and low albumin levels were found to be significant predictive factors for major lower limb amputation among patients with T2DM admitted for diabetic foot problems.
    Keywords: amputation; diabetes mellitus; diabetic foot; lower limb; type II.
  16. Ahmad A, Abdullah SRS, Hasan HA, Othman AR, Ismail N'
    Environ Sci Pollut Res Int, 2022 Jan;29(2):2579-2587.
    PMID: 34374006 DOI: 10.1007/s11356-021-15541-7
    The performance of local plants was tested using synthetic turbid water resembling real wastewater by measuring their ability to remove turbidity. The selected plants were A. indica, S. palustris, D. linearis, S. polyanthum, M. esculenta, P. sarmentosum, and M. malabathricum which can easily be found locally. The experiment was run based on coagulant dosages varied from 0 to 10 g/L for each plant with a rapid mixing speed at 180 rpm for 3 min, slow mixing speed at 10 rpm for 20 min, and settling time for 30 min. The results demonstrated that each plant has been capable of reducing turbidity by different amounts, with an increase in the coagulant dosage. The optimum coagulant dosages achieved for A. indica, S. palustris, S. polyanthum, and D. linearis were 10 g/L with turbidity removal at 26.9%, 24.9%, 24.9%, and 17.5%, respectively. P. sarmentosum and M. esculenta attained optimum coagulant dosages at 5 g/L with turbidity removal at 24.2% and 22.2%, and lastly M. malabathricum at 0.1 g/L (12.2%). P. sarmentosum was suggested to the best natural coagulant which achieved the highest removal of turbidity with a low dosage used.
  17. Shehadat SA, Gorduysus MO, Hamid SSA, Abdullah NA, Samsudin AR, Ahmad A
    Eur J Dent, 2018;12(4):574-578.
    PMID: 30369805 DOI: 10.4103/ejd.ejd_401_17
    OBJECTIVE: The objective of this study was to evaluate and compare the two scanning electron microscope (SEM) preparation protocols and determine the better SEM preparation technique to study stem cells on human amniotic membrane (hAM) scaffold.

    MATERIALS AND METHODS: Formaldehyde-based protocol and glutaraldehyde-based protocol were compared to evaluate the quality of SEM images for stem cells cultured on hAM scaffold.

    RESULTS: The results suggested that formaldehyde-based protocol is better than glutaraldehyde-based protocol in terms of showing clearer topography of the membrane as well as the boarders of the cells. To provide intact surface of the SEM sample and avoid possible ruptures of the hAM or the thin cell layer, it is recommended to perform the dehydration step using graded alcohol concentrations of 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%, one time for each and twice in 100% for 10 min each. Gold sputter-coating step is not recommended as it does not improve the image quality.

    CONCLUSIONS: To obtain clear SEM images, it is recommended to run a preliminary study to determine the better chemicals and conditions of sample preparation even when following preexisting protocols.

  18. Nazar M, Ul Hassan Shah M, Ahmad A, Goto M, Zaireen Nisa Yahya W, Moniruzzaman M
    Chemosphere, 2023 Dec;344:140412.
    PMID: 37827466 DOI: 10.1016/j.chemosphere.2023.140412
    Chemical dispersants are extensively used for marine oil spill remediation. However, the increased toxicity and low biodegradability of these dispersants restrict their employment in the marine environment. Hence, in this work, we have developed an eco-friendly formulation composed of an ionic liquid,1-butyl-3-methylimidazolium lauroyl sarcosinate [BMIM][Lausar] and sorbitan monooleate (Span) 80. Micellar and interfacial parameters, dispersion effectiveness, as well as the toxicity and biodegradability of the developed formulation were investigated. Micellar properties confirmed a high degree of synergism among the surfactant molecules and the formation of stable micelle. The dispersion effectiveness, at dispersant-to-oil ratio (DOR) of 1:25 (v/v), against three crude oils (Arab, Ratawi, and Doba) was assessed. We achieved a dispersion effectiveness of 68.49%, 74.05%, and 83.43% for Ratawi, Doba, and Arab crude oil, respectively, using a 70:30 (w/w) ratio of Span 80 to [BMIM][Lausar]. Furthermore, the results obtained from optical microscopy and particle size analysis (PSA) indicated that the oil droplet size decreased with higher DOR. Additionally, acute toxicity experiments were conducted on zebrafish (Danio rerio) using the developed formulation, confirming its non-toxic behavior, with LC50 values of 800 mg/L after 96 h. The formulation also exhibited high biodegradability, with only 25.01% of the original quantity remaining after 28 days. Hence, these results suggest that the new formulation has the potential to be a highly effective and environmentally friendly dispersant for oil spill remediation.
  19. Majid MF, Mohd Zaid HF, Abd Shukur MF, Ahmad A, Jumbri K
    Heliyon, 2023 Oct;9(10):e20743.
    PMID: 37867795 DOI: 10.1016/j.heliyon.2023.e20743
    In this study, the physicochemical properties and molecular interactions between zirconium-based metal-organic framework (UiO-66) and three different ionic liquids based on bis(trifluoromethanesulfonyl)imide anion (EMIM+, BMIM+ and OMIM+) was performed via a combined experimental and computational approach. The ionic liquid loaded UiO-66 or IL@UiO-66 was synthesized and characterized to understand the host-guest interaction. Density functional theory calculation was performed to analyse the electronic structure of IL@UiO-66 to provide molecular insight on the dominant interactions occurred in the hybrid material. Results showed that all ILs were successfully incorporated into the micropores of UiO-66. The 3D framework was retained even after loaded with ILs as analyzed from XRD pattern. FTIR spectrum reveals that interactions of ILs with UiO-66 influenced by the alkyl chain length of the cation. The anion has a profound affinity with the UiO-66 due to the presence of electronegative atoms. Phase transition study from DSC suggested that the incorporation of ILs has stabilized the framework of UiO-66 by shifting the endothermic peak to a higher state. These findings were further elaborated with DFT calculation. Geometrical optimizations confirmed the structural parameter changes of UiO-66 when loaded with ILs. These was mainly contributed by the non-covalent interactions which was confirmed by the reduced density gradient scattered plot. Another important findings are the strength of hydrogen bonding at the host-guest interface was influenced by the alkyl chain length. The molecular orbital analysis also shows that the size of alkyl chain influence the reactivity of the hybrid material. The present study provides fundamental insights on the molecular interaction of UiO-66 and ILs as a hybrid material, which can open new possibilities for advanced material for metal-organic framework applications in energy storage system, catalysis, gas storage and medicinal chemistry.
  20. Perialathan K, Rahman AB, Lim KH, Adon Y, Ahmad A, Juatan N, et al.
    Tob Induc Dis, 2018;16:55.
    PMID: 31516452 DOI: 10.18332/tid/99258
    INTRODUCTION: Electronic cigarettes (e-cigarettes) are new smoking devices that have gained popularity recently. However, there is limited evidence on e-cigarette consumption in Malaysia. This study aims to determine the prevalence, risk factors and perception associated with e-cigarette use among those attending government hospitals and health clinics in Malaysia.

    METHODS: A cross-sectional hospital-based study was conducted in seven public hospitals and health clinics in Malaysia, which were selected through a two-stage cluster sampling. A validated questionnaire was used to obtain data from the selected participants. Multivariable logistic regression was employed to determine the association between sociodemographics and perceptions of e-cigarette use.

    RESULTS: Almost three-quarters (73.6%; n=923/1254) of participants were aware of e-cigarettes and 13.2% (n=122/923) reported having ever used e-cigarettes. The prevalence was significantly higher among males (18.1%), smokers (21.4%), and younger age group 18-34 years (30.2%). Ever users showed favourable perceptions towards e-cigarettes compared to non-users (23.3% vs 30.14%, p<0.001). Multivariable logistic regression revealed that current smokers, younger age group and those possessing a positive perception towards e-cigarettes were likely to be ever users of e-cigarettes.

    CONCLUSIONS: The study showed that the awareness level of e-cigarettes was high amongst the population but the prevalence of ever e-cigarette user was moderate. Most of the ever e-cigarette users were male, current smokers, young adults and those with favourable perceptions towards e-cigarettes. Therefore, effective health educational activities regarding safe usage of e-cigarettes targeting those group identified in this study are warranted to reduce the negative outcomes from the use of this product.
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