Displaying publications 1 - 20 of 32 in total

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  1. Renewable energy in Southeast Asia: Policies and recommendations
    Erdiwansyah, Mamat R, Sani MSM, Sudhakar K
    Sci Total Environ, 2019 Jun 20;670:1095-1102.
    PMID: 31018425 DOI: 10.1016/j.scitotenv.2019.03.273
    Southeast Asian countries stand at a crossroads concerning their shared energy future and heavily rely on fossil fuels for transport and electricity. Within Asia, especially India and China lead the world renewable energy generation undergoing a period of energy transition and economic transformation. Southeast Asian countries have huge potentials for sustainable energy sources. However they are yet to perform globally in renewable energy deployment due to various challenges. The primary objective of the study is to examine the renewable energy growth and analyse the government policies to scale up the deployment of renewables for power generation substantially. The study also offers policy recommendations to accelerate renewable energy exploitation sustainably across the region. To achieve the ambitious target of 23% renewables in the primary energy mix by 2025, ASEAN Governments should take proactive measures like removal of subsidies of fossil fuels, regional market integration and rapid implementation of the existing project. Eventually, each of this strategy will necessitate sustained leadership, political determination, and concrete actions from stakeholders, in particular, increased cooperation across the region.
  2. Fulltext Thermomyces lanuginosus lipase-catalyzed synthesis of natural flavor esters in a continuous flow microreactor
    Gumel AM, Annuar MSM
    3 Biotech, 2016 Jun;6(1):24.
    PMID: 28330099 DOI: 10.1007/s13205-015-0355-9
    Enzymatic catalysis is considered to be among the most environmental friendly processes for the synthesis of fine chemicals. In this study, lipase from Thermomyces lanuginosus (Lecitase Ultra™) was used to catalyze the synthesis of flavor esters, i.e., methyl butanoate and methyl benzoate by esterification of the acids with methanol in a microfluidic system. Maximum reaction rates of 195 and 115 mM min(-1) corresponding to catalytic efficiencies (k cat/K M) of 0.30 and 0.24 min(-1) mM(-1) as well as yield conversion of 54 and 41 % were observed in methyl butanoate and methyl benzoate synthesis, respectively. Catalytic turnover (k cat) was higher for methyl butanoate synthesis. Rate of synthesis and yield decreased with increasing flow rates. For both esters, increase in microfluidic flow rate resulted in increased advective transport over molecular diffusion and reaction rate, thus lower conversion. In microfluidic synthesis using T. lanuginosus lipase, the following reaction conditions were 40 °C, flow rate 0.1 mL min(-1), and 123 U g(-1) enzyme loading found to be the optimum operating limits. The work demonstrated the application of enzyme(s) in a microreactor system for the synthesis of industrially important esters.
  3. Growth kinetics, effect of carbon substrate in biosynthesis of mcl-PHA by Pseudomonas putida Bet001
    Gumel AM, Annuar MS, Heidelberg T
    Braz J Microbiol, 2014;45(2):427-38.
    PMID: 25242925
    Growth associated biosynthesis of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) in Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. Models with substrate inhibition terms described well the kinetics of its growth. Selected fatty acids (C8:0 to C18:1) and ammonium were used as carbon and nitrogen sources during growth and PHA biosynthesis, resulting in PHA accumulation of about 50 to 69% (w/w) and PHA yields ranging from 10.12 g L(-1) to 15.45 g L(-1), respectively. The monomer composition of the PHA ranges from C4 to C14, and was strongly influenced by the type of carbon substrate fed. Interestingly, an odd carbon chain length (C7) monomer was also detected when C18:1 was fed. Polymer showed melting temperature (T m) of 42.0 (± 0.2) °C, glass transition temperature (T g) of -1.0 (± 0.2) °C and endothermic melting enthalpy of fusion (ΔHf) of 110.3 (± 0.1) J g(-1). The molecular weight (M w) range of the polymer was relatively narrow between 55 to 77 kDa.
  4. Thermokinetic comparison of trypan blue decolorization by free laccase and fungal biomass
    Razak NN, Annuar MS
    Appl Biochem Biotechnol, 2014 Mar;172(6):2932-44.
    PMID: 24464534 DOI: 10.1007/s12010-014-0731-7
    Free laccase and fungal biomass from white-rot fungi were compared in the thermokinetics study of the laccase-catalyzed decolorization of an azo dye, i.e., Trypan Blue. The decolorization in both systems followed a first-order kinetics. The apparent first-order rate constant, k1', value increases with temperature. Apparent activation energy of decolorization was similar for both systems at ∼ 22 kJ mol(-1), while energy for laccase inactivation was 18 kJ mol(-1). Although both systems were endothermic, fungal biomass showed higher enthalpy, entropy, and Gibbs free energy changes for the decolorization compared to free laccase. On the other hand, free laccase showed reaction spontaneity over a wider range of temperature (ΔT = 40 K) as opposed to fungal biomass (ΔT = 15 K). Comparison of entropy change (ΔS) values indicated metabolism of the dye by the biomass.
  5. High cell density fed-batch fermentations for lipase production: feeding strategies and oxygen transfer
    Salehmin MN, Annuar MS, Chisti Y
    Bioprocess Biosyst Eng, 2013 Nov;36(11):1527-43.
    PMID: 23539203 DOI: 10.1007/s00449-013-0943-1
    This review is focused on the production of microbial lipases by high cell density fermentation. Lipases are among the most widely used of the enzyme catalysts. Although lipases are produced by animals and plants, industrial lipases are sourced almost exclusively from microorganisms. Many of the commercial lipases are produced using recombinant species. Microbial lipases are mostly produced by batch and fed-batch fermentation. Lipases are generally secreted by the cell into the extracellular environment. Thus, a crude preparation of lipases can be obtained by removing the microbial cells from the fermentation broth. This crude cell-free broth may be further concentrated and used as is, or lipases may be purified from it to various levels. For many large volume applications, lipases must be produced at extremely low cost. High cell density fermentation is a promising method for low-cost production: it allows a high concentration of the biomass and the enzyme to be attained rapidly and this eases the downstream recovery of the enzyme. High density fermentation enhances enzyme productivity compared with the traditional submerged culture batch fermentation. In production of enzymes, a high cell density is generally achieved through fed-batch operation, not through perfusion culture which is cumbersome. The feeding strategies used in fed-batch fermentations for producing lipases and the implications of these strategies are discussed. Most lipase-producing microbial fermentations require oxygen. Oxygen transfer in such fermentations is discussed.
  6. Thermo-kinetics of lipase-catalyzed synthesis of 6-O-glucosyldecanoate
    Gumel AM, Annuar MS, Heidelberg T, Chisti Y
    Bioresour Technol, 2011 Oct;102(19):8727-32.
    PMID: 21816608 DOI: 10.1016/j.biortech.2011.07.024
    Lipase-catalyzed synthesis of 6-O-glucosyldecanoate from d-glucose and decanoic acid was performed in dimethyl sulfoxide (DMSO), a mixture of DMSO and tert-butanol and tert-butanol alone with a decreasing order of polarity. The highest conversion yield (> 65%) of decanoic acid was obtained in the blended solvent of intermediate polarity mainly because it could dissolve relatively large amounts of both the reactants. The reaction obeyed Michaelis-Menten type of kinetics. The affinity of the enzyme towards the limiting substrate (decanoic acid) was not affected by the polarity of the solvent, but increased significantly with temperature. The esterification reaction was endothermic with activation energy in the range of 60-67 kJ mol⁻¹. Based on the Gibbs energy values, in the solvent blend of DMSO and tert-butanol the position of the equilibrium was shifted more towards the products compared to the position in pure solvents. Monoester of glucose was the main product of the reaction.
  7. Ultrasound assisted lipase catalyzed synthesis of poly-6-hydroxyhexanoate
    Gumel AM, Annuar MS, Chisti Y, Heidelberg T
    Ultrason Sonochem, 2012 May;19(3):659-67.
    PMID: 22105013 DOI: 10.1016/j.ultsonch.2011.10.016
    Ultrasonic irradiation greatly improved the Candida antarctica lipase B mediated ring opening polymerization of ε-caprolactone to poly-6-hydroxyhexanoate in the ionic liquid 1-ethyl-3-methylimidazolium tetraflouroborate. Compared to the conventional nonsonicated reaction, sonication improved the monomer conversion by 63% and afforded a polymer product of a narrower molecular weight distribution and a higher degree of crystallinity. Under sonication, the polydispersity index of the product was ~1.44 compared to a value of ~2.55 for the product of the conventional reaction. With sonication, nearly 75% of the monomer was converted to product, but the conversion was only ~16% for the reaction carried out conventionally. Compared to conventional operation, sonication enhanced the rate of polymer propagation by >2-fold and the turnover number of the lipase by >3-fold.
  8. Lipase catalyzed ultrasonic synthesis of poly-4-hydroxybutyrate-co-6-hydroxyhexanoate
    Gumel AM, Annuar MS, Chisti Y
    Ultrason Sonochem, 2013 May;20(3):937-47.
    PMID: 23231942 DOI: 10.1016/j.ultsonch.2012.09.015
    Four different lipases were compared for ultrasound-mediated synthesis of the biodegradable copolymer poly-4-hydroxybutyrate-co-6-hydroxyhexanoate. The copolymerization was carried out in chloroform. Of the enzymes tested, Novozym 435 exhibited the highest copolymerization rate, in fact the reaction rate was observed to increase with about 26-fold from 30 to 50°C (7.9×10(-3)Ms(-1)), sonic power intensity of 2.6×10(3)Wm(-2) and dissipated energy of 130.4Jml(-1). Copolymerization rates with the Candida antarctica lipase A, Candida rugosa lipase, and Lecitase Ultra™ were lower at 2.4×10(-4), 1.3×10(-4) and 3.5×10(-4)Ms(-1), respectively. The catalytic efficiency depended on the enzyme. The efficiency ranged from 4.15×10(-3)s(-1)M(-1) for Novozym 435-1.48×10(-3)s(-1)M(-1) for C. rugosa lipase. Depending on the enzyme and sonication intensity, the monomer conversion ranged from 8.2% to 48.5%. The sonication power, time and temperature were found to affect the rate of copolymerization. Increasing sonication power intensity from 1.9×10(3) to 4.5×10(3)Wm(-2) resulted in an increased in acoustic pressure (P(a)) from 3.7×10(8) to 5.7×10(8)Nm(-2) almost 2.4-3.7 times greater than the acoustic pressure (1.5×10(8)Nm(-2)) that is required to cause cavitation in water. A corresponding acoustic particle acceleration (a) of 9.6×10(3)-1.5×10(4)ms(-2) was calculated i.e. approximately 984-1500 times greater than under the action of gravity.
  9. Enzymatic synthesis of 6-O-glucosyl-poly(3-hydroxyalkanoate) in organic solvents and their binary mixture
    Gumel AM, Annuar MS, Heidelberg T
    Int J Biol Macromol, 2013 Apr;55:127-36.
    PMID: 23305702 DOI: 10.1016/j.ijbiomac.2012.12.028
    The effects of organic solvents and their binary mixture in the glucose functionalization of bacterial poly-3-hydroxyalkanoates catalyzed by Lecitase™ Ultra were studied. Equal volume binary mixture of DMSO and chloroform with moderate polarity was more effective for the enzyme catalyzed synthesis of the carbohydrate polymer at ≈38.2 (±0.8)% reactant conversion as compared to the mono-phasic and other binary solvents studied. The apparent reaction rate constant as a function of medium water activity (aw) was observed to increase with increasing solvent polarity, with optimum aw of 0.2, 0.4 and 0.7 (±0.1) observed in hydrophilic DMSO, binary mixture DMSO:isooctane and hydrophobic isooctane, respectively. Molecular sieve loading between 13 to 15gL(-1) (±0.2) and reaction temperature between 40 to 50°C were found optimal. Functionalized PHA polymer showed potential characteristics and biodegradability.
  10. Ultrasound degradation of xanthan polymer in aqueous solution: Its scission mechanism and the effect of NaCl incorporation
    Saleh HM, Annuar MSM, Simarani K
    Ultrason Sonochem, 2017 Nov;39:250-261.
    PMID: 28732944 DOI: 10.1016/j.ultsonch.2017.04.038
    Degradation of xanthan polymer in aqueous solution by ultrasonic irradiation was investigated. The effects of selected variables i.e. sonication intensity, irradiation time, concentration of xanthan gum and molar concentration of NaCl in solution were studied. Combined approach of full factorial design and conventional one-factor-at-a-time was applied to obtain optimum degradation at sonication power intensity of 11.5Wcm-2, irradiation time 120min and 0.1gL-1xanthan in a salt-free solution. Molecular weight reduction of xanthan gum under sonication was described by an exponential decay function with higher rate constant for polymer degradation in the salt free solution. The limiting molecular weight where fragments no longer undergo scission was determined from the function. The incorporation of NaCl in xanthan solution resulted in a lower limiting molecular weight. The ultrasound-mediated degradation of aqueous xanthan polymer chain agreed with a random scission model. Side chain of xanthan polymer is proposed to be the primary site of scission action.
  11. Medium-chain-length poly-3-hydroxyalkanoates-carbon nanotubes composite anode enhances the performance of microbial fuel cell
    Hindatu Y, Annuar MSM, Subramaniam R, Gumel AM
    Bioprocess Biosyst Eng, 2017 Jun;40(6):919-928.
    PMID: 28341913 DOI: 10.1007/s00449-017-1756-4
    Insufficient power generation from a microbial fuel cell (MFC) hampers its progress towards utility-scale development. Electrode modification with biopolymeric materials could potentially address this issue. In this study, medium-chain-length poly-3-hydroxyalkanoates (PHA)/carbon nanotubes (C) composite (CPHA) was successfully applied to modify the surface of carbon cloth (CC) anode in MFC. Characterization of the functional groups on the anodic surface and its morphology was carried out. The CC-CPHA composite anode recorded maximum power density of 254 mW/m2, which was 15-53% higher than the MFC operated with CC-C (214 mW/m2) and pristine CC (119 mW/m2) as the anode in a double-chambered MFC operated with Escherichia coli as the biocatalyst. Electrochemical impedance spectroscopy and cyclic voltammetry showed that power enhancement was attributed to better electron transfer capability by the bacteria for the MFC setup with CC-CPHA anode.
  12. Analysis of Changes in Oil Palm Canopy Architecture From Basal Stem Rot Using Terrestrial Laser Scanner
    Azuan NH, Khairunniza-Bejo S, Abdullah AF, Kassim MSM, Ahmad D
    Plant Dis, 2019 Dec;103(12):3218-3225.
    PMID: 31596688 DOI: 10.1094/PDIS-10-18-1721-RE
    Basal stem rot (BSR), caused by the Ganoderma fungus, is an infectious disease that affects oil palm (Elaeis guineensis) plantations. BSR leads to a significant economic loss and reductions in yields of up to Malaysian Ringgit (RM) 1.5 billion (US$400 million) yearly. By 2020, the disease may affect ∼1.7 million tonnes of fresh fruit bunches. The plants appear symptomless in the early stages of infection, although most plants die after they are infected. Thus, early, accurate, and nondestructive disease detection is crucial to control the impact of the disease on yields. Terrestrial laser scanning (TLS) is an active remote-sensing, noncontact, cost-effective, precise, and user-friendly method. Through high-resolution scanning of a tree's dimension and morphology, TLS offers an accurate indicator for health and development. This study proposes an efficient image processing technique using point clouds obtained from TLS ground input data. A total of 40 samples (10 samples for each severity level) of oil palm trees were collected from 9-year-old trees using a ground-based laser scanner. Each tree was scanned four times at a distance of 1.5 m. The recorded laser scans were synched and merged to create a cluster of point clouds. An overhead two-dimensional image of the oil palm tree canopy was used to analyze three canopy architectures in terms of the number of pixels inside the crown (crown pixel), the degree of angle between fronds (frond angle), and the number of fronds (frond number). The results show that the crown pixel, frond angle, and frond number are significantly related and that the BSR severity levels are highly correlated (R2 = 0.76, P < 0.0001; R2 = 0.96, P < 0.0001; and R2 = 0.97, P < 0.0001, respectively). Analysis of variance followed post hoc tests by Student-Newman-Keuls (Newman-Keuls) and Dunnett for frond number presented the best results and showed that all levels were significantly different at a 5% significance level. Therefore, the earliest stage that a Ganoderma infection could be detected was mildly infected (T1). For frond angle, all post hoc tests showed consistent results, and all levels were significantly separated except for T0 and T1. By using the crown pixel parameter, healthy trees (T0) were separated from unhealthy trees (moderate infection [T2] and severe infection [T3]), although there was still some overlap with T1. Thus, Ganoderma infection could be detected as early as the T2 level by using the crown pixel and the frond angle parameters. It is hard to differentiate between T0 and T1, because during mild infection, the symptoms are highly similar. Meanwhile, T2 and T3 were placed in the same group, because they showed the same trend. This study demonstrates that the TLS is useful for detecting low-level infection as early as T1 (mild severity). TLS proved beneficial in managing oil palm plantation disease.
  13. Fulltext Radiological hazard associated with amang processing industry in Peninsular Malaysia and its environmental impacts
    Sanusi MSM, Ramli AT, Hashim S, Lee MH
    Ecotoxicol Environ Saf, 2021 Jan 15;208:111727.
    PMID: 33396058 DOI: 10.1016/j.ecoenv.2020.111727
    Continuous depletion in tin productions has led to a newly emerging industry that is a tin by-product (amang) processing industry to harness mega tons of tin by-products produced in the past. Amang composed of profitable multi-heavy minerals and rare-earth elements. With poorly established safety and health practices in operating plant, amang poses extremely high radioactivity problem associated with high occupational ionizing radiation exposures to workers and continuously impacting the local environment with radioactive contamination from industrial effluent and solid waste into lithosphere and water bodies. The radioactivity level of 238U and 232Th series in the mineral varies from few hundreds up to ~200,000 and ~400,000 Bq kg-1 respectively and are potential to yield more than ~ 30,000 nGy h-1 of gamma (γ) radiation exposure to plant workers. The study found out that for 8 h of work time, a worker is estimated to receive an average effective dose of 0.1 mSv per day from external γ radiation source with a maximum up to 2 mSv per day for extreme exposure situation. Interferences of different exposure routes for examples inhalation of equivalent equilibrium concentration (ECC) of 222Rn and 220Rn progenies and airborne long-lived α particles from the dusty working environment could pose a higher total effective dose as much as 5 mSv per day and 115 mSv per year. The value is 5 times higher than the annual dose limit for designated radiation worker (20 mSv) in Peninsular Malaysia. The study found that 41% of the total received an effective dose received by a worker is contributed by 222Rn, 32% of airborne particulates and dust, 23% from external γ exposure and 4% from 220Rn. Based on radioecological risk assessment, the study found out that the aquatic environment is the highly exposed group to ionizing radiation from industrial effluent discharge and sand residues. With the impotent establishment of radiation protection in the industry, plus the country newly introduced long-term plan to revive tin mining as well as its accessory amang mineral, it is necessary for the government to harmonize current regulation to improve the worker safety and health as well as sustaining local environment.
  14. Thermoplastic starch/beeswax blend: Characterization on thermal mechanical and moisture absorption properties
    Diyana ZN, Jumaidin R, Selamat MZ, Suan MSM
    Int J Biol Macromol, 2021 Nov 01;190:224-232.
    PMID: 34481857 DOI: 10.1016/j.ijbiomac.2021.08.201
    Cassava starch has acquired many attentions owing to its ability to be developed as thermoplastic cassava starch (TPCS) where it can be obtained in low cost, making it to be one of alternatives to substitute petroleum-based plastic. An attempt was made to investigate the thermal, mechanical and moisture absorption properties of thermoplastic cassava starch blending with beeswax (TPCS-BW) fabricated using hot moulding compression method in the range of beeswax loading from 0, 2.5, 5 to 10 wt%. Addition of beeswax has significantly reduced tensile strength, elongation and flexural strength while improving tensile modulus and flexural modulus until 5 wt% beeswax. Incorporation of 10 wt% beeswax has successfully produced the lowest value of moisture absorption and water solubility among the bio-composite which might be attributed to the beeswax's hydrophobic properties in improving water barrier of the TPCS-BW bio-composite. Furthermore, the addition of beeswax resulted in the appearance of irregular and rough fractured surface. Meanwhile, fourier transform infrared (FT-IR) spectroscopy presented that incorporation of beeswax in the mixture has considerably improve hydrogen bonding of blends indicating good interaction between starch and beeswax. Hence, beeswax with an appropriate loading value able to improve the functional properties of TPCS-BW bio-composite.
  15. Tabulation of organ dose conversion factors for terrestrial radioactivity monitoring program
    Sanusi MSM, Hassan WMSW, Hashim S, Ramli AT
    Appl Radiat Isot, 2021 Aug;174:109791.
    PMID: 34062400 DOI: 10.1016/j.apradiso.2021.109791
    Terrestrial radioactivity monitoring of 238U and 232Th series, and 40K in soil is an essential practice for radioactivity and radiation measurement of a place. In conventional practice, only basic data can be in-situ measured using a survey instrument, for example radioactivity concentration in soil and ambient dose equivalent rate. For other physical quantities, for example organ absorbed dose and organ equivalent dose, the measurement is impossible to be performed and can only be computed using Monte Carlo radiation transport simulations. In the past, most of the works only focused on calculating air-kerma-to-effective dose conversion factors. However, the information on organ dose conversion factors is scarcely documented and reported. This study was conducted to calculate organ absorbed and tissue-weighted equivalent dose conversion factors as a result of exposure from terrestrial gamma radiation. Series of organ dose conversion factors is produced based on computations from Monte Carlo MCNP5 simulations using modelled gamma irradiation geometry and established adult MIRD phantom. The study found out that most of the radiation exposed organs absorb energy at comparable rates, except for dense and superficial tissues i.e., skeleton and skin, which indicated slightly higher values. The good agreement between this work and previous studies demonstrated that our gamma irradiation geometry and modelling of gamma radiation sources are adequate. Therefore, the proposed organ dose conversion factors from this study are reasonably acceptable for dose estimation in environmental radioactivity monitoring practices.
  16. Psychosocial assessment of quarantine (sign-on and sign-off) among oil and gas workers in Malaysia during COVID-19 outbreak
    Shohaime NA, Masngut MI, Aris MSM
    Med J Malaysia, 2024 Mar;79(Suppl 1):96-103.
    PMID: 38555892
    INTRODUCTION: COVID-19 still wreaking havoc in Malaysia, with 3,221,680 cases and 32,326 deaths as of 20 February 2022. In the Oil and Gas industry, implementing quarantine before mobilising to or after mobilising from onshore and offshore locations was mandatory to help stop the spread of the virus. However, previous studies have shown that quarantine can significantly impact public mental health. This study intends to assess the psychosocial stress experienced by Oil and Gas industry employees during periods of quarantine in various regions (PMA: Terengganu, SBA: Sabah, SKA: Sarawak) and between onshore and offshore employees. Additionally, it aims to identify the factors that are linked to psychosocial stress in this workforce.

    MATERIALS AND METHODS: A cross-sectional study involving 86 respondents was conducted using an online survey between the middle of March and April 2022. The Perceived Stress Scale (PSS) developed by Cohen et al., (1983) was used to assess the stress levels of individuals. Data analysis was carried out using the SPSS statistical program, which included descriptive statistics, Mann-Whitney, Kruskal Wallis and Linear Regression tests.

    RESULTS: The majority of respondents, 75.6% (n=65) reported moderate stress levels, while 14.0% (n=12) declared severe stress levels. The Mann-Whitney test showed no significant difference in psychosocial stress scores among workers between onshore and offshore (χ2=-0.523, p=0.601), whereas the Kruskal Wallis test showed a significant difference in psychosocial stress scores among workers between states (PMA, SKA, and SBA) (χ2=6.415, p=0.040). According to the regression test, workers with medical histories of diabetes and Covid-19 (R2=0.158) (p<0.005) are two factors linked to psychosocial stress.

    CONCLUSION: The study found that there were significant differences in psychosocial stress among oil and gas workers between SKA, SBA, and PMA due to quarantine activity. Mobile workers and those with certain medical histories were identified as being particularly vulnerable to psychosocial stress. However, it was noted that the overall improvement in the quarantine period had a positive impact on the mental health of these workers.

  17. Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia
    Sanusi MS, Ramli AT, Gabdo HT, Garba NN, Heryanshah A, Wagiran H, et al.
    J Environ Radioact, 2014 Sep;135:67-74.
    PMID: 24787672 DOI: 10.1016/j.jenvrad.2014.04.004
    A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h(-1) to 500 nGy h(-1). The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h(-1). This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h(-1) (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation.
  18. Posterior reversible encephalopathy syndrome in systemic lupus erythematosus: pooled analysis of the literature reviews and report of six new cases
    Shaharir SS, Remli R, Marwan AA, Said MS, Kong NCT
    Lupus, 2013 Apr;22(5):492-6.
    PMID: 23435619 DOI: 10.1177/0961203313478303
    INTRODUCTION:Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disorder which is increasingly recognized to occur in systemic lupus erythematosus (SLE).
    OBJECTIVE: The purpose of this study was to identify the characteristics of SLE patients with PRES and the associated factors of the poor outcome among them.
    METHODS: We investigated SLE patients who developed PRES between 2005-2011 at the Universiti Kebangsaan Malaysia Medical Centre. A comprehensive literature search was done to find all published cases of PRES in SLE. Pooled analysis was conducted to identify the factors associated with poor outcome.
    RESULTS: There were 103 cases of PRES in SLE published in the literature but only 87 cases were included in the analysis in view of incomplete individual data in the remaining cases. The majority of the cases were Asians (74.2%), female (95.4%) with mean age of 26.3 ± 8.8 years. PRES was highly associated with active disease (97.5%), hypertension (91.7%) and renal involvement (85.1%). We found that 79 patients had a full recovery (90.8%) with a mean onset of full clinical recovery in 5.6 ± 4.1 days. On univariate analysis and logistic regression analysis the predictors of poor outcome, defined as incomplete clinical recovery or death, were intracranial hemorrhage, odds ratio (OR) 14 (1.1-187.2), p=0.04 and brainstem involvement in PRES, OR 10.9 (1.3-90.6), p=0.003.
    CONCLUSION: Intracranial hemorrhage and brainstem involvement were the two important predictors of poor outcome of PRES. Larger prospective studies are needed to further delineate the risk of poor outcome among them.
  19. Predicting terrestrial gamma dose rate based on geological and soil information: case study of Perak state, Malaysia
    Ramli AT, Apriantoro NH, Heryansyah A, Basri NA, Sanusi MS, Abu Hanifah NZ
    J Radiol Prot, 2016 Mar;36(1):20-36.
    PMID: 26583298 DOI: 10.1088/0952-4746/36/1/20
    An extensive terrestrial gamma radiation dose (TGRD) rate survey has been conducted in Perak State, Peninsular Malaysia. The survey has been carried out taking into account geological and soil information, involving 2930 in situ surveys. Based on geological and soil information collected during TGRD rate measurements, TGRD rates have been predicted in Perak State using a statistical regression analysis which would be helpful to focus surveys in areas that are difficult to access. An equation was formulated according to a linear relationship between TGRD rates, geological contexts and soil types. The comparison of in situ measurements and predicted TGRD dose rates was tabulated and showed good agreement with the linear regression equation. The TGRD rates in the study area ranged from 38 nGy h(-1) to 1039 nGy h(-1) with a mean value of 224  ±  138 nGy h(-1). This value is higher than the world average as reported in UNSCEAR 2000. The TGRD rates contribute an average dose rate of 1.37 mSv per year. An isodose map for the study area was developed using a Kriging method based on predicted and in situ TGRD rate values.
  20. The investigation of the skin biophysical measurements focusing on daily activities, skin care habits, and gender differences
    Hadi H, Awadh AI, Hanif NM, Md Sidik NF, Mohd Rani MR, Suhaimi MS
    Skin Res Technol, 2016 May;22(2):247-54.
    PMID: 26333416 DOI: 10.1111/srt.12257
    Skin, as a protective barrier to exogenous substances, can be modulated by various internal and external factors that can affect its functional state. In order to prevent the early symptoms and signs of diseases of the skin, frequent skin health assessment should be performed. The aims of the study were to evaluate four skin properties of transepidermal water loss (TEWL), hydration, elasticity, and pigmentation using a non-invasive skin assessment tool, DermaLab Combo(®) , and also to determine possible factors that may influence skin condition.
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