Displaying publications 1 - 20 of 27 in total

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  1. Fulltext Determination of lead, cations, and anions concentration in indoor and outdoor air at the primary schools in Kuala Lumpur
    Awang N, Jamaluddin F
    J Environ Public Health, 2014;2014:408275.
    PMID: 25136371 DOI: 10.1155/2014/408275
    This study was carried out to determine the concentration of lead (Pb), anions, and cations at six primary schools located around Kuala Lumpur. Low volume sampler (MiniVol PM10) was used to collect the suspended particulates in indoor and outdoor air. Results showed that the concentration of Pb in indoor air was in the range of 5.18 ± 1.08 μg/g-7.01 ± 0.08 μg/g. All the concentrations of Pb in indoor air were higher than in outdoor air at all sampling stations. The concentrations of cations and anions were higher in outdoor air than in indoor air. The concentration of Ca(2+) (39.51 ± 5.01 mg/g-65.13 ± 9.42 mg/g) was the highest because the cation existed naturally in soil dusts, while the concentrations of NO3 (-) and SO4 (2-) were higher in outdoor air because there were more sources of exposure for anions in outdoor air, such as highly congested traffic and motor vehicles emissions. In comparison, the concentration of NO3 (-) (29.72 ± 0.31 μg/g-32.00 ± 0.75 μg/g) was slightly higher than SO4 (2-). The concentrations of most of the parameters in this study, such as Mg(2+), Ca(2+), NO3 (-), SO4 (2-), and Pb(2+), were higher in outdoor air than in indoor air at all sampling stations.
  2. Wavelet-based time series model to improve the forecast accuracy of PM10 concentrations in Peninsular Malaysia
    Yong NK, Awang N
    Environ Monit Assess, 2019 Jan 11;191(2):64.
    PMID: 30635772 DOI: 10.1007/s10661-019-7209-6
    This study presents the use of a wavelet-based time series model to forecast the daily average particulate matter with an aerodynamic diameter of less than 10 μm (PM10) in Peninsular Malaysia. The highlight of this study is the use of a discrete wavelet transform (DWT) in order to improve the forecast accuracy. The DWT was applied to convert the highly variable PM10 series into more stable approximations and details sub-series, and the ARIMA-GARCH time series models were developed for each sub-series. Two different forecast periods, one was during normal days, while the other was during haze episodes, were designed to justify the usefulness of DWT. The models' performance was evaluated by four indices, namely root mean square error, mean absolute percentage error, probability of detection and false alarm rate. The results showed that the model incorporated with DWT yielded more accurate forecasts than the conventional method without DWT for both the forecast periods, and the improvement was more prominent for the period during the haze episodes.
  3. Multiple linear regression and regression with time series error models in forecasting PM10 concentrations in Peninsular Malaysia
    Ng KY, Awang N
    Environ Monit Assess, 2018 Jan 06;190(2):63.
    PMID: 29306973 DOI: 10.1007/s10661-017-6419-z
    Frequent haze occurrences in Malaysia have made the management of PM10 (particulate matter with aerodynamic less than 10 μm) pollution a critical task. This requires knowledge on factors associating with PM10 variation and good forecast of PM10 concentrations. Hence, this paper demonstrates the prediction of 1-day-ahead daily average PM10 concentrations based on predictor variables including meteorological parameters and gaseous pollutants. Three different models were built. They were multiple linear regression (MLR) model with lagged predictor variables (MLR1), MLR model with lagged predictor variables and PM10 concentrations (MLR2) and regression with time series error (RTSE) model. The findings revealed that humidity, temperature, wind speed, wind direction, carbon monoxide and ozone were the main factors explaining the PM10 variation in Peninsular Malaysia. Comparison among the three models showed that MLR2 model was on a same level with RTSE model in terms of forecasting accuracy, while MLR1 model was the worst.
  4. Fulltext Thermal Stability and Water Content Study of Void-Free Electrospun SPEEK/Cloisite Membrane for Direct Methanol Fuel Cell Application
    Awang N, Jaafar J, Ismail AF
    Polymers (Basel), 2018 Feb 15;10(2).
    PMID: 30966230 DOI: 10.3390/polym10020194
    Void-free electrospun SPEEK/Cloisite15A® densed (SP/e-spunCL) membranes are prepared. Different loadings of Cloisite15A® (0.10, 0.15, 0.20, 0.25 and 0.30 wt %) are incorporated into electrospun fibers. The physico-chemical characteristics (methanol permeability, water uptake and proton conductivity) of the membranes are observed. Thermal stability of all membranes is observed using Thermal Gravimetry Analysis (TGA). The thrree stages of degradation range between 163.1 and 613.1 °C. Differential Scanning Calorimetry (DSC) is used to study the wettability of the membranes. SP/e-spunCL15 shows the lowest freezing bound water of 15.27%, which contributed to the lowest methanol permeability. The non-freezing bound water that proportionally increased with proton conductivity of SP/e-spunCL15 membrane is the highest, 10.60%. It is suggested that the electrospinning as the fabricating method has successfully exfoliated the Cloisite in the membrane surface structure, contributing to the decrease of methanol permeability, while the retained water has led to the enhancement of proton conductivity. This new fabrication method of SP/e-spunCL membrane is said to be a desirable polymer electrolyte membrane for future application in direct methanol fuel cell field.
  5. Cytotoxic effect of organotin(IV) benzylisopropyldithiocarbamate compounds on Chang liver cell and hepatocarcinoma HepG2 cell
    Awang N, Kamaludin NF, Ghazali AR
    Pak J Biol Sci, 2011 Aug 01;14(15):768-74.
    PMID: 22303582
    Cancer is one of the main causes of mortality and morbidity in world. New compounds are currently being synthesized to combat this disease. The organotins are gaining more attention as anti-cancer agents due to their potent cytotoxicity properties. In this study, a series of newly synthesized organotins namely dimethyltin (IV) (compound 1), dibutyltin (IV) (compound 2) and triphenyltin (IV) benzylisopropyldithiocarbamate (compound 3) were assessed for their cytotoxic activities against human Chang liver cells and hepatocarcinoma HepG2 cells. The cytotoxicity of these organotins in both cells upon 24 h treatment was assessed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Compound 2 and 3 exhibited potent cytotoxic activities towards both cells where the IC50 values were less then 10 microM. The IC50 value for compound 2 was 2.5 microM in Chang liver cells and 7.0 microM in HepG2 cells whereas compound 3 exhibited an IC50 value of 1.5 microM in Chang liver cells and 2.5 microM in HepG2 cells. Therefore, compound 2 and 3 were more toxic against human Chang liver cells as compared to hepatocarcinoma HepG2 cells. Interestingly, compound 1 did not have any IC50 value in both cells and hence can be classified as non-toxic. In conclusion, organotin (IV) benzylisopropyldithiocarbamate with insertion of dibutyl and triphenyl functional group possess potent cytotoxicity properties. Structural modification of these compounds can be carried out in further studies to produce less or non toxic effects towards normal human cell.
  6. Persistence of cognitive deficits following paediatric head injury without professional rehabilitation in rural East Coast Malaysia
    Abdullah JM, Kumaraswamy N, Awang N, Ghazali MM, Abdullah MR
    Asian J Surg, 2005 Jul;28(3):163-7.
    PMID: 16024307
    To use data from a prospective, longitudinal study to determine whether psychomotor functions improve spontaneously during the first year following paediatric traumatic brain injury without modern rehabilitation facilities in a rural area of Malaysia.
  7. Distinct coordination geometries in bis-[N,N-bis-(2-meth-oxy-eth-yl)di-thio-carbamato-κ(2) S,S']di-phenyltin(IV) and bis-[N-(2-meth-oxy-eth-yl)-N-methyl-dithio-carbamato-κ(2) S,S']di-phenyl-tin(IV): crystal structures and Hirshfeld surface analysis
    Mohamad R, Awang N, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Aug 1;72(Pt 8):1130-7.
    PMID: 27536397 DOI: 10.1107/S2056989016011385
    The crystal and mol-ecular structures of two di-phenyl-tin bis-(di-thio-carbamate)s, [Sn(C6H5)2(C5H10NOS2)2], (I), and [Sn(C6H5)2(C7H14NO2S2)2], (II), are described. In (I), in which the metal atom lies on a twofold rotation axis, the di-thio-carbamate ligand coordinates with approximately equal Sn-S bond lengths and the ipso-C atoms of the Sn-bound phenyl groups occupy cis-positions in the resulting octa-hedral C2S4 donor set. A quite distinct coordination geometry is noted in (II), arising as a result of quite disparate Sn-S bond lengths. Here, the four S-donors define a trapezoidal plane with the ipso-C atoms lying over the weaker of the Sn-S bonds so that the C2S4 donor set defines a skewed trapezoidal bipyramid. The packing of (I) features supra-molecular layers in the ab plane sustained by methyl-ene-C-H⋯π(Sn-ar-yl) inter-actions; these stack along the c-axis direction with no specific inter-actions between them. In (II), supra-molecular chains along the b-axis direction are formed by methyl-ene-C-O(ether) inter-actions; these pack with no directional inter-actions between them. A Hirshfeld surface analysis was conducted on both (I) and (II) and revealed the dominance of H⋯H inter-actions contributing to the respective surfaces, i.e. >60% in each case, and other features consistent with the description of the mol-ecular packing above.
  8. Fulltext Synthesis and cytotoxic activity of organotin(IV) diallyldithiocarbamate compounds as anticancer agent towards colon adenocarcinoma cells (HT-29)
    Haezam FN, Awang N, Kamaludin NF, Mohamad R
    Saudi J Biol Sci, 2021 May;28(5):3160-3168.
    PMID: 34025187 DOI: 10.1016/j.sjbs.2021.02.060
    Context: Diphenyltin(IV) diallyldithiocarbamate compound (Compound 1) and triphenyltin(IV) diallyldithiocarbamate compound (Compound 2) are two newly synthesised compounds of organotin(IV) with diallyldithiocarbamate ligands.

    Objective: To assess the cytotoxic effects of two synthesised compounds against HT-29 human colon adenocarcinoma cells and human CCD-18Co normal colon cells.

    Materials and methods: Two successfully synthesised compounds were characterised using elemental (carbon, hydrogen, nitrogen, and sulphur) analysis, Fourier-Transform Infrared (FTIR), and 1H, 13C 119Sn Nucleus Magnetic Resonance (NMR) spectroscopies. The single-crystal structure of both compounds was determined by X-ray single-crystal analysis. The cytotoxicity of the compounds was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazholium bromide (MTT) assay upon 24 h of treatment. While the mode of cell death was determined based on the externalisation of phosphatidylserine using a flow cytometer.

    Results: The elemental analysis data of the two compounds showed an agreement with the suggested formula of (C6H5)2Sn[S2CN(C3H5)2]2 for Compound 1 and (C6H5)3Sn[S2CN(C3H5)2] for Compound 2. The two major peaks of infrared absorbance, i.e., ν(C = N) and ν(C = S) were detected at the range of 1475-1479 cm-1 and 972-977 cm-1, respectively. The chemical shift of carbon in NCS2 group for Compound 1 and 2 were found at 200.82 and 197.79 ppm. The crystal structure of Compound 1 showed that it is six coordinated and crystallised in monoclinic, P21/c space group. While the crystal structure of Compound 2 is five coordinated and crystallised in monoclinic, P21/c space group. The cytotoxicity (IC50) of the two compounds against HT-29 cell were 2.36 μM and 0.39 μM. Meanwhile, the percentage of cell death modes between 60% and 75% for compound 1 and compound 2 were mainly due to apoptosis, suggesting that both compounds induced growth arrest.

    Conclusion: Our study concluded that the synthesised compounds showed potent cytotoxicity towards HT-29 cell, with the triphenyltin(IV) compound showing the highest effect compared to diphenyltin(IV).

  9. Fulltext Cellular Basis of Organotin(IV) Derivatives as Anticancer Metallodrugs: A Review
    Syed Annuar SN, Kamaludin NF, Awang N, Chan KM
    Front Chem, 2021;9:657599.
    PMID: 34368075 DOI: 10.3389/fchem.2021.657599
    Organotin(IV) compounds have wide applications in industrial and agricultural fields owing to their ability to act as poly(vinyl chloride) stabilizers and catalytic agents as well as their medicinal properties. Moreover, organotin(IV) compounds may have applications as antitumor, anti-inflammatory, antifungal, or antimicrobial agents based on the observation of synergistic effects following the binding of their respective ligands, resulting in the enhancement of their biological activities. In this review, we describe the antiproliferative activities of organotin(IV) compounds in various human cancer cell lines based on different types of ligands. We also discuss the molecular mechanisms through which organotin(IV) compounds induce cell death via apoptosis through the mitochondrial intrinsic pathway. Finally, we present the mechanisms of cell cycle arrest induced by organotin(IV) compounds. Our report provides a basis for studies of the antitumor activities of organotin(IV) compounds and highlights the potential applications of these compounds as anticancer metallodrugs with low toxicity and few side effects.
  10. Respiratory health status of workers that exposed to welding fumes at Lumut shipyard
    Ithnin A, Zubir A, Awang N, Mohamad Sulaiman NN
    Pak J Biol Sci, 2019 Jan;22(3):143-147.
    PMID: 30972984 DOI: 10.3923/pjbs.2019.143.147
    BACKGROUND AND OBJECTIVE: Welding fume exposure has led to the respiratory problems among welders including cough, phlegm, chest illnesses, nausea and fatigue. Inadequate ventilation during welding works causes the situation to worsen. Welding fumes can cause a decrease in lung function among welders. Chronic exposure will lead to other health effects especially COPD (Chronic Obstructive Pulmonary Disease). The objective of this study is to determine the exposure of welding fumes (Cd, Fe, Pb and Zn) towards respiratory health including lung function test (FEV1, FVC, FEV1/FVC, PEFR) of workers in Lumut shipyard, Perak.

    MATERIAL AND METHODS: This research study the relationship between exposures of welding fumes towards lung function test among workers in Lumut shipyard, Perak. Lung function test was measured by spirometry among 30 welders and 31 non-welders. The concentration welding fume exposure was measured using OSHA ID-121 method. Sociodemographic data, respiratory symptoms and smoking habit data was analyzed based on the ATS 1987 questionnaire.

    RESULTS: The mean concentration for Pb in welding fumes was 2.752 mg m-3 which is above 0.5 mg m-3 PEL-TWA. The FEV1 and FVC readings showed significant different between welders and non-welders (p = 0.001). Cough and phlegm symptoms showed significant different between welders and non-welders (p = 0.001). Welders had higher prevalence in smoking habit than the non-welders. Chest illnesses symptom showed an association with the smoking habit (p = 0.01).

    CONCLUSION: There is relationship between welding fumes exposure on lung function test of workers in Lumut shipyard. Pb in welding fumes has high concentration and exceeded PEL-TWA level. The FEV1 and FVC in welders are lower than non-welder due to the fumes exposure. Welders showed higher respiratory symptoms than non-welders. Smoking habit is a contributing factor towards respiratory problem.
  11. Synthesis, characterization and crystal structure of organotin(IV) N-butyl-N-phenyldithiocarbamate compounds and their cytotoxicity in human leukemia cell lines
    Kamaludin NF, Awang N, Baba I, Hamid A, Meng CK
    Pak J Biol Sci, 2013 Jan 01;16(1):12-21.
    PMID: 24199481
    Organotin complexes are recognized as the biologically active compounds in inducing cancerous cells death at very low doses. To date, organotin compounds currently appear among the most potent candidates in research related to the new anticancer drugs. In this study, new organotin(IV) N-butyl-N-phenyldithiocarbamate compounds have been successfully synthesized between the reaction of N-butylaniline amine with organotin(IV) chloride in 1:2/1:1 molar ratio. All compounds were characterized using the elemental analysis, FT-IR and NMR spectroscopy. The single crystal structure was determined by X-ray single crystal analysis. The elemental analysis showed good agreement with the suggested formula (C4H9)2Sn[S2CN(C4H9)(C6H5)]2 (Compound 1 and 2), (C6H5)2Sn[S2CN(C4H9)(C6H5)]2 (Compound 3) and (C6H5)3Sn[S2CN(C4H9)(C6H5)] (Compound 4). The important infrared absorbance peaks, v (C = N) and v(C = S) were detected in range between 1457-1489 cm(-1) and 951-996 cm(-1), respectively. The chemical shift of carbon in NCS2 group obtained from 13C NMR was found in range 198.86-203.53 ppm. The crystal structure of compound 4 showed that the dithiocarbamate ligand coordinates in a monodentate fashion. It crystallized in monoclinic P2(1)/n space group with the crystal cell parameter: a = 10.0488(1) angstroms, b = 18.0008(2) angstroms, c = 15.2054(2) angstroms, beta = 102.442(1) degrees and R = 0.044. The cytotoxicity (IC50) of these compounds against Jurkat E6.1 and K-562 leukemia cells were in the range between 0.4-0.8 and 1.8-5.3 microM, respectively as assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazholium bromide (MTT) assay. In conclusion, our study demonstrate that all compounds showed potent cytotoxicity towards both cell lines tested with the triphenyltin(IV) compound displayed the greatest effect.
  12. Cytotoxicity of triphenyltin(IV) methyl- and ethylisopropyldithiocarbamate compounds in chronic myelogenus leukemia cell line (K-562)
    Awang N, Kamaludin NF, Hamid A, Mokhtar NW, Rajab NF
    Pak J Biol Sci, 2012 Sep 01;15(17):833-8.
    PMID: 24163967
    Studies on the discovery of new cancer treatment by using metal-based compounds such as tin (Sn) has now greatly being synthesized and evaluated to identify their effectiveness and suitability to be developed as a new anticancer drug.

    APPROACH: This study was carried out to evaluate the cytotoxicity of triphenyltin(lV) methylisopropyldithiocarbamate (compound 1) and triphenyltin(IV) ethylisopropyldithiocarbamate (compound (2) on chronic myelogenus leukemia cells. The determination of their cytotoxicity (IC50) at different time of exposure and concentration was carried out through the employment of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay.

    RESULTS: The IC50 values obtained for compound 1 and 2 following treatment at 24, 48 and 72 h were 0.660, 0.223, 0.370 microM and 0.677, 0.306, 0.360 microM, respectively. Cell morphological changes such as apoptotic and necrotic features were also been observed.

    CONCLUSION: The compounds tested were found to give cytotoxic effect against chronic myelogenus leukemia (K-562) cell at a micromolar dose. Thus, further study on their specific mechanism of actions in the human cells should be carried out to elucidate their potential as an anticancer agent.

  13. Composition of heavy metals and airborne fibers in the indoor environment of a building during renovation
    Latif MT, Baharudin NH, Velayutham P, Awang N, Hamdan H, Mohamad R, et al.
    Environ Monit Assess, 2011 Oct;181(1-4):479-89.
    PMID: 21181256 DOI: 10.1007/s10661-010-1843-3
    The renovation of a building will certainly affect the quality of air in the vicinity of where associated activities were undertaken, this includes the quality of air inside the building. Indoor air pollutants such as particulate matter, heavy metals, and fine fibers are likely to be emitted during renovation work. This study was conducted to determine the concentration of heavy metals, asbestos and suspended particulates in the Biology Building, at the Universiti Kebangsaan, Malaysia (UKM). Renovation activities were carried out widely in the laboratories which were located in this building. A low-volume sampler was used to collect suspended particulate matter of a diameter size less than 10 μm (PM₁₀) and an air sampling pump, fitted with a cellulose ester membrane filter, were used for asbestos sampling. Dust was collected using a small brush and scope. The concentration of heavy metals was determined through the use of inductively coupled plasma-mass spectroscopy and the fibers were counted through a phase contrast microscope. The concentrations of PM₁₀ recorded in the building during renovation action (ranging from 166 to 542 μg m⁻³) were higher than the value set by the Department of Safety and Health for respirable dust (150 μg m⁻³). Additionally, they were higher than the value of PM₁₀ recorded in indoor environments from other studies. The composition of heavy metals in PM₁₀ and indoor dust were found to be dominated by Zn and results also showed that the concentration of heavy metals in indoor dust and PM₁₀ in this study was higher than levels recorded in other similar studies. The asbestos concentration was 0.0038 ± 0.0011 fibers/cc. This was lower than the value set by the Malaysian Department of Occupational, Safety and Health (DOSH) regulations of 0.1 fibers/cc, but higher than the background value usually recorded in indoor environments. This study strongly suggests that renovation issues need to be considered seriously by relevant stakeholders within the university in order to ensure that the associated risks toward humans and indoor environment are eliminated, or where this is not feasible, minimized as far as possible.
  14. Fulltext Phytochemical and In Vitro Genotoxicity Studies of Standardized Ficus deltoidea var. kunstleri Aqueous Extract
    Muhammad H, Omar MH, Rasid ENI, Suhaimi SN, Mohkiar FH, Siu LM, et al.
    Plants (Basel), 2021 Feb 11;10(2).
    PMID: 33670296 DOI: 10.3390/plants10020343
    The present study was carried out to assess the genotoxicity potential of Ficus deltoidea var. kunstleri aqueous extract (FDAE) using standard in vitro assays. The DNA damage of V79B cells was measured using the alkaline comet assay treated at 0.1 mg/mL (IC10) and 0.3 mg/mL (IC25) of FDAE together with positive and negative controls. For in vitro micronucleus assay, the V79B cells were treated with FDAE at five different concentrations (5, 2.5, 1.25, 0.625, and 0.3125 mg/mL) with and without S9 mixture. The bacteria reverse mutation assay of FDAE was performed on Salmonella typhimurium strains TA98, 100, 1535, 1537, and Escherichia coli strain WP2uvrA using pre-incubation method in the presence or in the absence of an extrinsic metabolic system (S9 mixture). FDAE at 0.1 and 0.3 mg/mL significantly increased DNA damage in both comet tail and tail moment (p < 0.05). No significant changes were detected in the number of micronucleated cell when compared to control. Tested at the doses up to 5000 µg/plate, the FDAE did not increase the number of revertant colonies for all strains. In conclusion, further investigation needs to be conducted in animal model to confirm the non-genotoxicity activities of FDAE.
  15. Fulltext Di-n-butyl-bis-[N-(2-meth-oxy-eth-yl)-N-methyl-dithio-carbamato-κ2S,S']tin(IV): crystal structure and Hirshfeld surface analysis
    Mohamad R, Awang N, Kamaludin NF, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Feb 01;73(Pt 2):260-265.
    PMID: 28217355 DOI: 10.1107/S2056989017001098
    The complete mol-ecule of the title compound, [Sn(C4H9)2(C5H10NOS2)2], is generated by a crystallographic mirror plane, with the SnIV atom and the two inner methyl-ene C atoms of the butyl ligands lying on the mirror plane; statistical disorder is noted in the two terminal ethyl groups, which deviate from mirror symmetry. The di-thio-carbamate ligand coordinates to the metal atom in an asymmetric mode with the resulting C2S4 donor set defining a skew trapezoidal bipyramidal geometry; the n-butyl groups are disposed to lie over the longer Sn-S bonds. Supra-molecular chains aligned along the a-axis direction and sustained by methyl-ene-C-H⋯S(weakly coordinating) inter-actions feature in the mol-ecular packing. A Hirshfeld surface analysis reveals the dominance of H⋯H contacts in the crystal.
  16. Fulltext Crystal structures and Hirshfeld surface analyses of bis-[N,N-bis-(2-meth-oxy-eth-yl)di-thio-carbamato-κ2S,S']di-n-butyl-tin(IV) and [N-(2-meth-oxy-eth-yl)-N-methyl-dithio-carbamato-κ2S,S']tri-phenyl-tin(IV)
    Mohamad R, Awang N, Kamaludin NF, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2018 Mar 01;74(Pt 3):302-308.
    PMID: 29765711 DOI: 10.1107/S2056989018001901
    The crystal and mol-ecular structures of the two title organotin di-thio-carbamate compounds, [Sn(C4H9)2(C7H14NO2S2)2], (I), and [Sn(C6H5)3(C5H10NOS2)], (II), are described. Both structures feature asymmetrically bound di-thio-carbamate ligands leading to a skew-trapezoidal bipyramidal geometry for the metal atom in (I) and a distorted tetra-hedral geometry in (II). The complete mol-ecule of (I) is generated by a crystallographic twofold axis (Sn site symmetry 2). In the crystal of (I), mol-ecules self-assemble into a supra-molecular array parallel to (10-1) via methyl-ene-C-H⋯O(meth-oxy) inter-actions. In the crystal of (II), supra-molecular dimers are formed via pairs of weak phenyl-C-H⋯π(phen-yl) contacts. In each of (I) and (II), the specified assemblies connect into a three-dimensional architecture without directional inter-actions between them. Hirshfeld surface analyses confirm the importance of H⋯H contacts in the mol-ecular packing of each of (I) and (II), and in the case of (I), highlight the importance of short meth-oxy-H⋯H(but-yl) contacts between layers.
  17. [N-Benzyl-N-(2-phenyl-eth-yl)di-thio-carbamato-κ(2)S,S']tri-phenyl-tin(IV) and [bis-(2-meth-oxy-eth-yl)di-thio-carbamato-κ(2)S,S']tri-phenyl-tin(IV): crystal structures and Hirshfeld surface analysis
    Mohamad R, Awang N, Kamaludin NF, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Oct 1;72(Pt 10):1480-1487.
    PMID: 27746946
    The crystal and mol-ecular structures of two tri-phenyl-tin di-thio-carbamates, [Sn(C6H5)3(C16H16NS2)], (I), and [Sn(C6H5)3(C7H14NO2S2)], (II), are described. In (I), the di-thio-carbamate ligand coordinates the Sn(IV) atom in an asymmetric manner, leading to a highly distorted trigonal-bipyramidal coordination geometry defined by a C3S2 donor set with the weakly bound S atom approximately trans to one of the ipso-C atoms. A similar structure is found in (II), but the di-thio-carbamate ligand coordinates in an even more asymmetric fashion. The packing in (I) features supra-molecular chains along the c axis sustained by C-H⋯π inter-actions; chains pack with no directional inter-actions between them. In (II), supra-molecular layers are formed, similarly sustained by C-H⋯π inter-actions; these stack along the b axis. An analysis of the Hirshfeld surfaces for (I) and (II) confirms the presence of the C-H⋯π inter-actions but also reveals the overall dominance of H⋯H contacts in the respective crystals.
  18. Gene Expression Profiling associated with Hepatoxicity in Pregnant Rats treated with Ubi Gadong (Dioscorea hispida) Extract
    Faradianna Lokman E, Muhammad H, Awang N, Hasyima Omar M, Mansor F, Saparuddin F
    Int J Biomed Sci, 2017 Mar;13(1):26-34.
    PMID: 28533734
    Dioscorea hispida (D.hispida) is the most well-known starchy tuber in Malaysia and called 'ubi gadong'. Despite concerns over toxicity effects, the tuber is known to possess therapeutic values due to the presence of bioactive compounds such as saponins. This study was performed to identify the changes in gene expression profiles associated with hepatoxicity in pregnant rat treated with D.hispida using RT² Profiler PCR Array. The identification of steroidal saponins from D.hispida was carried out by UHPLC/MS method. Treatment of D.hispida caused mortality when dosage above 2000 mg/kg b.w. was given to pregnant rats. The PCR array showed that several genes were significantly up and down-regulated upon treatment with D.hispida. Treatment of D.hispida at 2000 mg/kg b.w leads to significant upregulation of several genes such as Btg2, Gsr, L2hgdn, S100a8, Slc17a3, Bhmt, Cd68, Cyp1a2 whereas several genes were downregulated such as Abcb1a, Aldoa, Cdc14b, Icam1, Krt18, Hpn and Maob. The consumption of D.hispida extract when taken at lower dosage of 2000 mg/kg may not be harmful to rats. D.hispida extract given at the highest dosage to pregnant rats caused alterations of several genes categorized in different hepatotoxic group functions such as necrosis, cholestasis and phospholipodisis.
  19. Effects of wastewater type on stability and operating conditions control strategy in relation to the formation of aerobic granular sludge - a review
    Hamiruddin NA, Awang NA, Mohd Shahpudin SN, Zaidi NS, Said MAM, Chaplot B, et al.
    Water Sci Technol, 2021 Nov;84(9):2113-2130.
    PMID: 34810301 DOI: 10.2166/wst.2021.415
    Currently, research trends on aerobic granular sludge (AGS) have integrated the operating conditions of extracellular polymeric substances (EPS) towards the stability of AGS systems in various types of wastewater with different physical and biochemical characteristics. More attention is given to the stability of the AGS system for real site applications. Although recent studies have reported comprehensively the mechanism of AGS formation and stability in relation to other intermolecular interactions such as microbial distribution, shock loading and toxicity, standard operating condition control strategies for different types of wastewater have not yet been discussed. Thus, the dimensional multi-layer structural model of AGS is discussed comprehensively in the first part of this review paper, focusing on diameter size, thickness variability of each layer and diffusion factor. This can assist in facilitating the interrelation between disposition and stability of AGS structure to correspond to the changes in wastewater types, which is the main objective and novelty of this review.
  20. Fulltext A review on the potential of photocatalysis in combatting SARS-CoV-2 in wastewater
    Nasir AM, Awang N, Hubadillah SK, Jaafar J, Othman MHD, Wan Salleh WN, et al.
    J Water Process Eng, 2021 Aug;42:102111.
    PMID: 35592059 DOI: 10.1016/j.jwpe.2021.102111
    Photocatalytic technology offers powerful virus disinfection in wastewater via oxidative capability with minimum harmful by-products generation. This review paper aims to provide state-of-the-art photocatalytic technology in battling transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater. Prior to that, the advantages and limitations of the existing conventional and advanced oxidation processes for virus disinfection in water systems were thoroughly examined. A wide spectrum of virus degradation by various photocatalysts was then considered to understand the potential mechanism for deactivating this deadly virus. The challenges and future perspectives were comprehensively discussed at the end of this review describing the limitations of current photocatalytic technology and suggesting a realistic outlook on advanced photocatalytic technology as a potential solution in dealing with similar upcoming pandemics. The major finding of this review including discovery of a vision on the possible photocatalytic approaches that have been proven to be outstanding against other viruses and subsequently combatting SARS-CoV-2 in wastewater. This review intends to deliver insightful information and discussion on the potential of photocatalysis in battling COVID-19 transmission through wastewater.
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