Displaying all 17 publications

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  1. Ya'aini N, Amin NA, Asmadi M
    Bioresour Technol, 2012 Jul;116:58-65.
    PMID: 22609656 DOI: 10.1016/j.biortech.2012.03.097
    Conversion of glucose, empty fruit bunch (efb) and kenaf to levulinic acid over a new hybrid catalyst has been investigated in this study. The characterization and catalytic performance results revealed that the physico-chemical properties of the new hybrid catalyst comprised of chromium chloride and HY zeolite increased the levulinic acid production from glucose compared to the parent catalysts. Optimization of the glucose conversion process using two level full factorial designs (2(3)) with two center points reported 55.2% of levulinic acid yield at 145.2 °C, 146.7 min and 12.0% of reaction temperature, reaction time and catalyst loading, respectively. Subsequently, the potential of efb and kenaf for producing levulinic acid at the optimum conditions was established after 53.2% and 66.1% of efficiencies were reported. The observation suggests that the hybrid catalyst has a potential to be used in biomass conversion to levulinic acid.
  2. Amin NA, Akhtar J, Rai HK
    Water Sci Technol, 2011;63(8):1651-6.
    PMID: 21866764
    The performances of HZSM-5 and transition metal-loaded HZSM-5 (Mn, Cu, Fe, Ti) catalysts during catalytic ozonation of phenol have been investigated. It was observed the performance order for removal of phenol and COD was Mn/HZSM-5 > Fe/HZSM-5 > Cu/HZSM-5 > Ti/HZSM-5 > HZSM-5. The presence of metals on HZSM-5 enhanced the phenol removal capability of HZSM-5. Mn loading on HZSM-5 was optimized due to its high phenol removal capability amongst metal-loaded HZSM-5 catalysts. Experimental results suggested that low amount of Mn loading on HZSM-5 was sufficient for HZSM-5 to act as catalyst and adsorbent. A maximum of 95.8 wt% phenols and 70.2 wt% COD were removed over 2 wt% Mn/HZSM-5 in 120 min. It was supposed that transition metals mainly acted as ozone decomposers due to their multiple oxidation states that enhanced the ozonation of phenol.
  3. Zainol MM, Amin NA, Asmadi M
    Bioresour Technol, 2015 Aug;190:44-50.
    PMID: 25919936 DOI: 10.1016/j.biortech.2015.04.067
    The aim of this work was to study the potential of biofuel and biomass processing industry side-products as acid catalyst. The synthesis of carbon cryogel from lignin-furfural mixture, prepared via sol-gel polycondensation at 90°C for 0.5h, has been investigated for biodiesel production. The effect of lignin to furfural (L/F) ratios, lignin to water (L/W) ratios and acid concentration on carbon cryogel synthesis was studied. The carbon cryogels were characterized and tested for oleic acid conversion. The thermally stable amorphous spherical carbon cryogel has a large total surface area with high acidity. Experimental results revealed the optimum FAME yield and oleic acid conversion of 91.3wt.% and 98.1wt.%, respectively were attained at 65°C for 5h with 5wt.% catalyst loading and 20:1 methanol to oleic acid molar ratio. Therefore, carbon cryogel is highly potential for heterogeneous esterification of free fatty acid to biodiesel.
  4. Abdul Halim S, Mohd Amin NA
    BMJ Case Rep, 2018 Oct 21;2018.
    PMID: 30344146 DOI: 10.1136/bcr-2018-225751
    Osmotic demyelination syndrome commonly affects the pons and infrequently involves the extrapontine region. We report a patient with severe hyponatraemia who developed osmotic demyelination syndrome as a consequence of rapid sodium correction. The condition manifested as acute severe parkinsonism, bilateral ptosis and gaze impairment. MRI revealed typical features of central pontine and extrapontine myelinolysis. The patient improved gradually after treatment with a combination of levodopa, intravenous immunoglobulin and dexamethasone. However, it is important to emphasise that the improvement of neurological symptoms is not necessarily causal with these experimental therapies.
  5. Jaliliannosrati H, Amin NA, Talebian-Kiakalaieh A, Noshadi I
    Bioresour Technol, 2013 May;136:565-73.
    PMID: 23567732 DOI: 10.1016/j.biortech.2013.02.078
    The synthesis of fatty acid ethyl esters (FAEEs) by a two-step in situ (reactive) esterification/transesterification from Jatropha curcas L. (JCL) seeds using microwave system has been investigated. Free fatty acid was reduced from 14% to less than 1% in the first step using H2SO4 as acid catalyst after 35 min of microwave irradiation heating. The organic phase in the first step was subjected to a second reaction by adding 5 N KOH in ethanol as the basic catalyst. Response surface methodology (RSM) based on central composite design (CCD) was utilized to design the experiments and analyze the influence of process variables (particles seed size, time of irradiation, agitation speed and catalyst loading) on conversion of triglycerides (TGs) in the second step. The highest triglycerides conversion to fatty acid ethyl esters (FAEEs) was 97.29% at the optimum conditions:<0.5mm seed size, 12.21 min irradiation time, 8.15 ml KOH catalyst loading and 331.52 rpm agitation speed in the 110 W microwave power system.
  6. Misson M, Haron R, Kamaroddin MF, Amin NA
    Bioresour Technol, 2009 Jun;100(11):2867-73.
    PMID: 19232488 DOI: 10.1016/j.biortech.2008.12.060
    The effect of chemical pretreatments using NaOH, H(2)O(2), and Ca(OH)(2) on Empty Palm Fruit Bunches (EPFB) to degrade EPFB lignin before pyrolysis was investigated. Spectrophotometer analysis proved consecutive addition of NaOH and H(2)O(2) decomposed almost 100% of EPFB lignin compared to 44% for the Ca(OH)(2), H(2)O(2) system while NaOH and Ca(OH)(2) used exclusively could not alter lignin much. Next, the pretreated EPFB was catalytically pyrolyzed. Experimental results indicated the phenolic yields over Al-MCM-41 and HZSM-5 catalysts were 90 wt% and 80 wt%, respectively compared to 67 wt% yield for the untreated sample under the same set of conditions. Meanwhile, the experiments with HY zeolite yielded 70 wt% phenols.
  7. Sidik DA, Ngadi N, Amin NA
    Bioresour Technol, 2013 May;135:690-6.
    PMID: 23186683 DOI: 10.1016/j.biortech.2012.09.041
    The production of lignin from empty fruit bunch (EFB) has been carried out using liquefaction method with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid (IL), in presence of sulfuric acid (H2SO4) as a catalyst. Response surface methodology (RSM) based on a factorial Central Composite Design (CCD) was employed to identify the optimum condition for lignin yield. The result indicated that the second order model was adequate for all the independent variables on the response with R(2)=0.8609. The optimum temperature, time, ionic liquid to EFB ratio, and catalyst concentration were 150.5 °C, 151 min, 3:1 wt/wt and 4.73 wt%, respectively for lignin yield=26.6%. The presence of lignin liquefied product was confirmed by UV-Vis and FTIR analysis. It was also demonstrated lignin extraction from lignocellulosic using recycled IL gave sufficient performance.
  8. Amin NA, Quek KF, Oxley JA, Noah RM, Nordin R
    Int J Occup Environ Med, 2015 10;6(4):232-42.
    PMID: 26498051 DOI: 10.15171/ijoem.2015.632
    BACKGROUND: The Job Content Questionnaire (M-JCQ) is an established self-reported instrument used across the world to measure the work dimensions based on the Karasek's demand-control-support model.

    OBJECTIVE: To evaluate the psychometrics properties of the Malay version of M-JCQ among nurses in Malaysia.

    METHODS: This cross-sectional study was carried out on nurses working in 4 public hospitals in Klang Valley area, Malaysia. M-JCQ was used to assess the perceived psychosocial stressors and physical demands of nurses at their workplaces. Construct validity of the questionnaire was examined using exploratory factor analysis (EFA). Cronbach's α values were used to estimate the reliability (internal consistency) of the M-JCQ.

    RESULTS: EFA showed that 34 selected items were loaded in 4 factors. Except for psychological job demand (Cronbach's α 0.51), the remaining 3 α values for 3 subscales (job control, social support, and physical demand) were greater than 0.70, indicating acceptable internal consistency. However, an item was excluded due to poor item-total correlation (r<0.3). The final M-JCQ was consisted of 33 items.

    CONCLUSION: The M-JCQ is a reliable and valid instrument to measure psychosocial and physical stressors in the workplace of public hospital nurses in Malaysia.

  9. Jamal AbuAlRoos N, Azman MN, Baharul Amin NA, Zainon R
    Phys Med, 2020 Oct;78:48-57.
    PMID: 32942196 DOI: 10.1016/j.ejmp.2020.08.017
    PURPOSE: The main objective of this study was to evaluate the efficacy of tungsten carbide as new lead-free radiation shielding material in nuclear medicine by evaluating the attenuation properties.

    MATERIALS AND METHODS: The elemental composition of tungsten carbide was analysed using Field-Emission Scanning Electron Microscopy (FESEM) with energy dispersive X-ray (EDX). The purity of tungsten carbide was 99.9%, APS: 40-50 µm. Three discs of tungsten carbide was fabricated with thickness of 0.1 cm, 0.5 cm and 1.0 cm. Three lead discs with similar thickness were used to compare the attenuation properties with tungsten carbide discs. Energy calibration of gamma spectroscopy was performed by using 123I, 133Ba, 152Eu, and 137Cs. Gamma radiation from these sources were irradiated on both materials at energies ranging from 0.160 MeV to 0.779 MeV. The experimental attenuation coefficients of lead and tungsten carbide were compared with theoretical attenuation coefficients of both materials from NIST database. The half value layer and mean free path of both materials were also evaluated in this study.

    RESULTS: This study found that the peaks obtained from gamma spectroscopy have linear relationship with all energies used in this study. The relative differences between the measured and theoretical mass attenuation coefficients are within 0.19-5.11% for both materials. Tungsten carbide has low half value layer and mean free path compared to lead for all thickness at different energies.

    CONCLUSION: This study shows that tungsten carbide has high potential to replace lead as new lead-free radiation shielding material in nuclear medicine.

  10. Amin NA, Quek KF, Oxley JA, Noah R, Nordin R
    Int J Occup Environ Med, 2018 04;9(2):69-78.
    PMID: 29667644 DOI: 10.15171/ijoem.2018.1158
    BACKGROUND: Emotional distress is becoming a great concern and is more common in both developed and developing countries. It is associated with several disease conditions.

    OBJECTIVE: To determine the prevalence of self-perceived emotional distress and its relation to work-related musculoskeletal disorders (WRMSDs) in nurses.

    METHODS: A self-administered questionnaire survey was carried out on 660 female nurses working in public hospitals in the Klang Valley, Malaysia. The validated Malay version of the standardized Nordic musculoskeletal questionnaire (M-SNMQ) was used to identify the annual prevalence of WRMSDs; perceived emotional distress was assessed using the validated Malay short version, depression, anxiety, and stress (M-DASS) instrument. In addition, socio-demographic and occupational profiles of the participants were considered. Factors associated with WRMSDs were identified using logistic regression analysis.

    RESULTS: A total of 376 nurses completed the survey (response rate 83.3%). 73.1% of the nursing staffs experienced WRMSDs in at least one anatomical site 12 months prior to the study. 75% of nurses expressed emotional distress. Of these, over half also reported anxiety and stress. Multiple logistic regression analysis showed that stress and anxiety significantly increased the risk of WRMSDs by approximately twofold.

    CONCLUSION: There were significant associations between emotional distress and WRMSDs. Future longitudinal studies are therefore needed to investigate and identify the sources of emotional distress (non-occupational and occupational) to be used to establish preventive strategies to reduce the risk of WRMSDs.

  11. Mat Amin NA, Nor Mohamed I, Lai YS
    Transfus Apher Sci, 2023 Oct;62(5):103798.
    PMID: 37661487 DOI: 10.1016/j.transci.2023.103798
  12. Amin NA, Nordin R, Fatt QK, Noah RM, Oxley J
    PMID: 25852937 DOI: 10.1186/s40557-014-0023-2
    OBJECTIVE: This study examined the relationships between psychosocial work factors and risk of WRMSDs among public hospital nurses in the Klang Valley, Malaysia.

    METHODS: We conducted a cross-sectional study among 660 public hospital nurses. A self-administered questionnaire was used to collect data on the occurrence of WRMSDs according to body regions, socio-demographic profiles, occupational information and psychosocial risk factors. 468 questionnaires were returned (response rate of 71%), and 376 questionnaires qualified for subsequent analysis. Univariate analyses were applied to test for mean and categorical differences across the WRMSDs; multiple logistic regression was applied to predict WRMSDs based on the Job Strain Model's psychosocial risk factors.

    RESULTS: Over two thirds of the sample of nurses experienced discomfort or pain in at least one site of the musculoskeletal system within the last year. The neck was the most prevalent site (48.94%), followed by the feet (47.20%), the upper back (40.69%) and the lower back (35.28%). More than 50% of the nurses complained of having discomfort in region one (neck, shoulders and upperback) and region four (hips, knees, ankles, and feet). The results also revealed that psychological job demands, job strain and iso-strain ratio demonstrated statistically significant mean differences (p

  13. Wong SL, Ngadi N, Amin NA, Abdullah TA, Inuwa IM
    Environ Technol, 2016;37(2):245-54.
    PMID: 26150081 DOI: 10.1080/09593330.2015.1068376
    Pyrolysis of low density polyethylene (LDPE) waste from local waste separation company in subcritical water was conducted to investigate the effect of reaction time, temperature, as well as the mass ratio of water to polymer on the liquid yield. The data obtained from the study were used to optimize the liquid yield using response surface methodology. The range of reaction temperature used was 162-338°C, while the reaction time ranged from 37 min to 143 min, and the ratio of water to polymer ranged from 1.9 to 7.1. It was found that pyrolysis of LDPE waste in subcritical water produced hydrogen, methane, carbon monoxide and carbon dioxide, while the liquid product contained alkanes and alkenes with 10-50 carbons atoms, as well as heptadecanone, dichloroacetic acid and heptadecyl ester. The optimized conditions were 152.3°C, reaction time of 1.2 min and ratio of water solution to polymer of 32.7, with the optimum liquid yield of 13.6 wt% and gases yield of 2.6 wt%.
  14. Latiff NA, Ong PY, Abd Rashid SNA, Abdullah LC, Mohd Amin NA, Fauzi NAM
    Sci Rep, 2021 08 27;11(1):17297.
    PMID: 34453075 DOI: 10.1038/s41598-021-96623-x
    Cosmos caudatus (C. caudatus) is a medicinal plant that is high in bioactive compounds such as phenolics. In this study, an ultrasound extraction method was used to optimise the extraction of bioactive compounds from C. caudatus leaves. Response surface methodology (RSM) based on a Box-Behnken design (BBD) was applied to obtain the optimum extraction parameters which is solid-liquid ratio (10-30 g/mL), particle size (180-850 µm) and extraction time (20-30 min) for maximal quercitrin and total phenolic content (TPC) yields. Analysis of antimicrobial activity was performed against two human pathogenic microbes: Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by the agar well diffusion method. The optimal ultrasonic extraction condition was as follow: solvent-liquid ratio of 1:28 (g/mL), particle size of 485 µm, and duration of 30 min, respectively. Remarkably, extraction using ultrasonic method had recovered more bioactive content and antioxidant activity than the Soxhlet method. The extract also exhibited good antimicrobial activities. Due to the above findings, the ultrasonic extraction was found to be suitable to improve recovery extraction of quercitrin and TPC from C. caudatus leaves. It also opens the possibility that the plant extract can be used for functional food and antimicrobial agents in various applications.
  15. Chua LS, Amin NA, Neo JC, Lee TH, Lee CT, Sarmidi MR, et al.
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Dec 15;879(32):3909-19.
    PMID: 22119436 DOI: 10.1016/j.jchromb.2011.11.002
    A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4ɛ-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.
  16. Amir SN, Juliana N, Azmani S, Abu IF, Talib AHQA, Abdullah F, et al.
    J Relig Health, 2021 Sep 18.
    PMID: 34536189 DOI: 10.1007/s10943-021-01408-1
    Religiosity and spirituality have previously been found to have significant effects on mental and physical health. This study aimed to compare elderly people utilizing different types of religious activities in their daily routine and the effects upon their quality of life and cognitive function. A cross-sectional study was conducted among elderly people dwelling in suburban areas of Malaysia. The Malay version of Short Form (36) Health Survey (SF-36), Geriatric Depression Scale (GDS-15), Older Americans Resources and Services's Instrumental Activities of Daily Living (OARS's IADL), and the Montreal Cognitive Assessment (MoCA) questionnaires were used in this study. Independent t test was utilized to determine the difference in the quality of life and the cognitive function between groups of elderly people that were categorized based on their level of participation in different religious activities. The study involved 432 participants. The mean score for all domain of SF-36 was significantly higher among those who engaged in the religious activities as compared to those elderly who were either less engaged or did not practice religious activities. The mean score of GDS-15, OARS's IADL, and MoCA was also significantly higher among those who participated in religious activities. There was a significant impact on the quality of life and cognitive function among elderly people practicing religious activities. This study proved the importance of practicing religious activities among the elderly in achieving healthy aging.
  17. Osman E, Amin NA, Noon TPM, Lahat SNH, Rosli MS, Sham SF, et al.
    Am J Trop Med Hyg, 2022 Jul 25;107(3):636-9.
    PMID: 35895335 DOI: 10.4269/ajtmh.22-0076
    Strongyloides infection may develop into fatal hyperinfection and dissemination syndrome in immunocompromised hosts. Despite suboptimal specificity issues, the detection of IgG antibodies by ELISA has been central in the serodiagnosis of Strongyloides infection. Recently, an IgG4-based lateral-flow test (SsRapid) using recombinant NIE (rNIE) protein with good diagnostic performance has been reported. This study assessed the result concordance between a commercial IgG-ELISA and the SsRapid. Additionally, we determined the Strongyloides seroprevalence and its association with clinical manifestations. Immunocompromised patients (N = 200) were from Hospital Canselor Tuanku Muhriz, Kuala Lumpur, Malaysia, and were diagnosed with HIV/AIDS, hematological malignancy, and solid organ cancers. Their plasma samples were tested using a commercial IgG-ELISA and SsRapid. A fair concordance (κ = 0.27-0.33; P < 0.05) among the tests was demonstrated. The SsRapid exhibited a significantly higher (P < 0.05) seroprevalence (10.5% [21/200]) compared with IgG-ELISA (7.5% [15/200]). After adsorption with rNIE, all SsRapid-positive samples tested negative with the rapid test, thus showing binding specificity. There was no significant association with clinical manifestations. This study revealed that SsRapid is a useful diagnostic tool for Strongyloides infection, and there is a notable seroprevalence among the immunocompromised patients.
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