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Showing papers in "Sains Malaysiana in 2019"


Journal ArticleDOI
TL;DR: The introduction of natural materials into the coagulation-flocculation process need to be practiced as common as possible as mentioned in this paper, however, the application of natural coagulants itself as the primary treatment is not sufficient due to the rise in constraints which limited its performance.
Abstract: The introduction of natural materials into the coagulation-flocculation process need to be practiced as common as possible. The previous literature indicated that utilization of natural material is actually worth to be developed and if possible, into the commercial one. However, the application of natural coagulants itself as the primary treatment is not sufficient, due to the rise in constraints which limited its performance. Emerging technologies and depth studies are actually helping these limited conditions to grow them as good as the performance of chemical coagulants. Alternatively, the natural-based coagulants are commonly used as coagulant aids alongside chemical coagulants, which have created a highlight in water research. This review covers the type of coagulants used in the coagulation-flocculation of wastewater treatment especially in the usage of natural-based coagulants. This review paper also outlines the future prospects of natural materials as aids and its potential as sustainable composite coagulants.

68 citations


Journal ArticleDOI
TL;DR: In this article, a theoretical study is presented for three-dimensional flow of bioconvection nanofluids containing gyrotactic microorganisms over a bi-axial stretching sheet, where suitable similarity transformations are used to reduce the partial differential equation system into a nonlinear ordinary differential system.
Abstract: A theoretical study is presented for three-dimensional flow of bioconvection nanofluids containing gyrotactic microorganisms over a bi-axial stretching sheet. The effects of anisotropic slip, thermal jump and mass slip are considered in the mathematical model. Suitable similarity transformations are used to reduce the partial differential equation system into a nonlinear ordinary differential system. The transformed nonlinear ordinary differential equations with appropriate transformed boundary conditions are solved numerically with the bvp4c procedure in the symbolic software, MATLAB. The mathematical computations showed that an increase in Brownian motion parameter corresponds to a stronger thermophoretic force which encourages transport of nanoparticles from the hot bi-axial sheet to the quiescent fluid. This increases the nanoparticle volume fraction boundary layer. Fluid temperature and thermal boundary layer thickness are decreased with increasing stretching rate ratio of the bi-axial sheet. The present simulation is of relevance in the fabrication of bio-nanomaterials and thermally-enhanced media for bio-inspired fuel cells.

48 citations


Journal ArticleDOI
TL;DR: In this paper, the MHD stagnation point flow of a nanofluid towards a permeable stretching/shrinking sheet with chemical reaction effect is investigated and the governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations using a similarity transformation which are then solved numerically using the boundary value problem solver, bvp4c built in Matlab software.
Abstract: The magnetohydrodynamic (MHD) stagnation-point flow of a nanofluid towards a permeable stretching/shrinking sheet with chemical reaction effect is investigated. The governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations using a similarity transformation which are then solved numerically using the boundary value problem solver, bvp4c built in Matlab software. The numerical results are obtained for the skin friction coefficient, local Nusselt number, local Sherwood number as well as the velocity, temperature and concentration profiles for some values of the governing parameters, namely suction/injection parameter and chemical reaction parameter. Dual solutions are found to exist for a certain range of the stretching/shrinking parameter. A stability analysis is performed to determine which solutions are stable and physically reliable. It is found that the first solutions are stable and the second solutions are unstable.

47 citations


Journal ArticleDOI
TL;DR: In this paper, the potential effect of linoleic acid based on its interaction on epidermal fatty acid binding protein (E-FABP) was studied by bioinformatics approach with reverse docking technique using palmitic acid as a control compound.
Abstract: The fatty acid analysis in Pliek U and its bioinformatic studies had been carried out and reported. Herein, fatty acids were analyzed by gas chromatography-mass spectrometry (GC-MS), meanwhile their potential effect, based on its interaction on epidermal fatty acid binding protein (E-FABP), was studied by bioinformatics approach with reverse docking technique using palmitic acid as a control compound. For the stated purpose, two Pliek U extracts were prepared, namely ethanolic Pliek U extract (EPUE), and ethanolic of residue hexane of Pliek U extract (ERHPUE). The GC-MS results showed that lauric, myristic, palmitic, and oleic acids were predominant, followed by stearic, capric, linoleic, and caprylic acids. Reverse docking results showed that linoleic acid had the lowest binding affinity (-5.9 kcal/mol) and was strongly bound to E-FABP on the same side of amino acid GLN A98, ARG A81, TYR A22, and LYS A61. These findings indicated that linoleic acid has a potential utility as a drug candidate for atopic dermatitis treatment.

37 citations


Journal ArticleDOI
TL;DR: In this paper, highly porous activated carbon was produced from rice straw by carbonization and followed by activation using potassium hydroxide (KOH). Activated carbon samples were prepared under different activation temperatures, and their physical and chemical properties were characterized accordingly.
Abstract: In this study, highly porous activated carbon was produced from rice straw by carbonization and followed by activation using potassium hydroxide (KOH). Activated carbon samples were prepared under different activation temperatures, i.e., 650, 750 and 850°C, and their physical and chemical properties were characterized accordingly. The BET surface area of the activated carbon samples was increased from 520 to 1048 m2/g with the increase of activation temperature from 650 to 850°C. These values were much higher than the non-activated rice straw carbon i.e., 1.16 m2/g. The pore sizes of the rice straw activated carbon were found to be mainly in mesopore size range of 2-50 nm. Total carbon content of the AC sample was increased from 8.35% to 31.73% with the increase of activation temperature from 650 to 850°C. XRD and Raman spectroscopy confirmed the graphite properties of the activated carbons produced. SEM images proved high porosity of the AC after KOH activation.

36 citations


Journal ArticleDOI
TL;DR: The mycorrhiza-released glomalin has represented potential functioning in soil ecosystems, which include promoting the storage of soil organic carbon, improving the structure of soil aggregates, enhancing the resistance of plants, and reducing the metal toxicity of plants as discussed by the authors.
Abstract: Glomalin that is a kind of glycoprotein produced by arbuscular mycorrhizal fungi in the phylum Glomeromycota, has some characteristics of hydrophobins with insolubility and difficulty in its extraction. The protein is highly homologous with heat shock protein 60. In soils, glomalin is measured as glomalin-related soil protein (GRSP). GRSP is highly positively correlated with soil aggregate stability, because it is a new component of soil organic matter. The mycorrhiza-released glomalin has represented potential functioning in soil ecosystems, which include promoting the storage of soil organic carbon, improving the structure of soil aggregates, enhancing the resistance of plants, and reducing the metal toxicity of plants. In addition, some potted and field experiments have been performed to exogenously apply the GRSP in crop plants to confirm the GRSP roles. Hence, GRSP is one of the most significant multidisciplinary topics between fungal physiology and soil biochemistry. Despite much work performed on glomalin from 1996, there are still gaps of GRSP that needs to be solved, including purification, structural features and environmental responses.

36 citations


Journal ArticleDOI
TL;DR: In this article, a study was conducted to determine essential-toxic element accumulations in drinking water of settlement areas located in Ergene River Basin and evaluated the water quality in terms of local public health.
Abstract: Ergene River Basin is the most significant aquatic habitat for Thrace Region and also one of the most polluted watersheds in Turkey. The objectives of this study were to determine some essential-toxic element accumulations in drinking water of settlement areas located in Ergene River Basin and evaluated the water quality in terms of local public health. Drinking water samples were collected from 30 stations in dry (summer) season of 2018. Cluster Analysis (CA) was used to classify the investigated elements and villages and Weighted Arithmetic Water Quality Index (WAWQI) was used to assess the water quality. According to results of elemental CA, 11 statistically significant clusters were formed in terms of elemental densities and according to results of locational CA, 3 statistically significant clusters were formed in terms of drinking water qualities. According to results of WAWQI, the risk sequence of the elements in drinking water of the system as follows: Se > As > Mo > B > Ba > Cr > Pb > Mn > Ni > Cd > Cu. Although Ergene River Basin is known as a very contaminated freshwater ecosystem, it was determined that the groundwater of the basin has I. - II class water quality, in general. Selenium accumulations detected in almost all the investigated villages exceeded the drinking water limit of 10 ppb. Arsenic, boron and molybdenum accumulations detected in some villages exceeded the drinking water standards. Although concentrations of some elements in some locations were exceed the limit values and recorded as quite high levels, the majority of investigated element concentrations in drinking water of the basin have been found to be in the range of human consumption standards.

30 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed two new collinearity diagnostics for the detection of multicollinearness among regressors, based on coefficient of determination and adjusted coefficients of determination from auxiliary regression of regressors.
Abstract: The problem of multicollinearity compromises the numerical stability of the regression coefficient estimate and cause some serious problem in validation and interpretation of the model. In this paper, we propose two new collinearity diagnostics for the detection of collinearity among regressors, based on coefficient of determination and adjusted coefficient of determination from auxiliary regression of regressors. A Monte Carlo simulation study has been conducted to compare the existing and proposed collinearity diagnostic tests. Comparison of diagnostics on some existing collinear data are also made.

29 citations


Journal ArticleDOI
TL;DR: In this article, the effects of alkaline treatments on the mechanical properties of kenaf fibres and interfacial shear properties (IFSS) of the resulted composites were systematically evaluated.
Abstract: Kenaf fibres demonstrate enormous potential in fibre reinforced composites with the excellent performance and environmental benefits. In this work, kenaf fibres were treated with NaOH at the concentrations of 1%, 2%, and 3%. Effects of the alkaline treatments on the mechanical properties of fibre and interfacial shear properties (IFSS) of the resulted composites were systematically evaluated. In addition, relationship between tensile strength and surface friction coefficient of kenaf fibre was shown. Relationship between tensile strength of fibre and IFSS of composites were explored. They were conducted by correlation analysis method. The results indicated that after NaOH treatment, kenaf fibres has increased in tensile strength, surface roughness, friction coefficient, but decreased in diameter. Tensile properties, flexural properties and water absorption of unidirectional kenaf fibre reinforced epoxy resin composites have improved. IFSS of composite treated at 2% alkali has increased by 10.34%, compared to composites untreated fibres. Correlation analysis indicated that there was no significant correlation between kenaf fibre tensile strength and IFSS of the composite. On the other hand, there was significant correlation between kenaf fibre surface friction and the IFSS of the composite with the correlation coefficient of 0.905.

28 citations


Journal ArticleDOI
TL;DR: In this article, the structural characterisation, thermal degradation and water absorption ability of the untreated and NaOH-treated coir fibre polymer composites have been studied, and it was shown that the NaOH treatment removed hemicelluloses as evidenced by the absence of absorption bands at 1724.36 cm-1 and changes the absorption intensity at bands 1244.09 cm −1 and 1249.87 cm−1 due to the loss of lignin.
Abstract: The alkaline treatment with 5 wt. % sodium hydroxide (NaOH) solution at room temperature for 24 and 48 h was performed on coir fibre. The structural characterisation, thermal degradation and water absorption ability of the untreated and NaOH-treated coir fibre polymer composites have been studied. Scanning electron microscope (SEM) images showed that coir fibres treated with NaOH have rough surface texture and the roughness of the fibre surface becomes significant as the duration of the NaOH treatment increased. Fourier transform infrared (FTIR) spectra confirmed that NaOH treatment removed hemicelluloses as evidenced by the absence of absorption bands at 1724.36 cm-1 and changes the absorption intensity at bands 1244.09 cm-1and 1249.87 cm-1 due to the loss of lignin. NaOH-treated coir fibre composites demonstrated better thermal stability at low temperature degradation. At high temperature, the thermal stability was reduced due to the decreased of residual lignin content. The water absorption of the NaOH-treated coir fibre composites was lower than untreated coir composite contributed by better interfacial adhesion between the NaOH-treated coir fibre to epoxy resin.

27 citations


Journal ArticleDOI
TL;DR: In this article, activated carbon from Bambusa vulgaris var. striata was produced by chemical activation using NaOH for mercury adsorption, and the effect of initial concentrations of 50 and 100 mg/L on the breakthrough characteristics of the adorption process was defined.
Abstract: Pollution by mercury dissolved in aqueous media causes a crucial problem for health and environment. In this study, activated carbon from Bambusa vulgaris var. striata was produced by chemical activation using NaOH for mercury adsorption. The effects of mercury initial concentrations namely 50 and 100 mg/L on the breakthrough characteristics of the adsorption process were defined. The mechanism of the adsorption process through the fixed-bed column was fitted to the Thomas model. The activated carbon was characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The adsorption study with a continuous system and using the Thomas model showed that the highest adsorption capacity (q0) of mercury ions is 218.08 mg/g. It can be concluded that activated carbon from Bambusa vulgaris var. striata has a great potential to act as an adsorbent to remove mercury from water.

Journal ArticleDOI
TL;DR: In this article, the chemical composition of honey samples produced by Heterotrigona itama and Tetrigona binghami which originated from Sarawak, Malaysia was compared.
Abstract: This study aims to compare the chemical composition of honey samples produced by Heterotrigona itama and Tetrigona binghami which originated from Sarawak, Malaysia. One hundred and six (106) honey samples were collected from local bee farms and analysed in terms of their chemical profiles. The chemical analysis conducted includes physicochemical composition such as moisture, total phenolic content, sugar, 5-hydroxymethylfurfural (5-HMF), pH and organic acids and proximate analysis which included ash, protein, carbohydrates and energy. Independent T-test was used as a statistical tool to investigate the significant difference between the composition of both honey samples. The results showed that honey samples of Heterotrigona itama and Tetrigona binghami possessed significant difference (p<0.05) in moisture, total phenolic content, fructose, glucose, pH, protein, gluconic acid, acetic acid, ash, carbohydrates and energy. The honey samples of Heterotrigona itama exhibited significantly higher fructose and glucose at the average of 22.00 ± 3.48 g/ 100 g and 23.45 ± 3.23 g/100 g, respectively. Besides, the honey samples also possessed higher pH value, gluconic acid, ash, carbohydrates and energy. Meanwhile, Tetrigona binghami honey samples possessed significantly (p< 0.05) higher moisture content, total phenolic content, protein and acetic acid compared to the Heterotrigona itama’s honey samples. To conclude, the geographical and floral origins of honey are the two important quality parameters which fundamentally affect the physical-chemical properties as well as biological activities of honey samples.

Journal ArticleDOI
TL;DR: In this article, an approximation method based on the Laguerre polynomials was presented to obtain the solutions of the fractional linear Fredholm integro-differential equations.
Abstract: The main purpose of this study was to present an approximation method based on the Laguerre polynomials to obtain the solutions of the fractional linear Fredholm integro-differential equations. This method transforms the integro-differential equation to a system of linear algebraic equations by using the collocation points. In addition, the matrix relation for Caputo fractional derivative of Laguerre polynomials is also obtained. Besides, some examples are presented to illustrate the accuracy of the method and the results are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors used a combination of Remote Sensing, Geographic Information System, logistic regression, and descriptive statistics to quantify and analyze the data and found that during the overall study period (1986-2016), grass/grazing land, agricultural land, and bare land have increased by 124, 42, and 34% respectively, whereas scattered acacia woodland, bush/shrubland, and swampy/marshy land have declined by 52, 50, and 31%, in that order.
Abstract: Land use-land cover change (LULCC) is driven by the interplay of forcing factors that act at global, regional, and local levels. Previous studies investigated mainly the basic socioeconomic drivers of LULCC. However, these studies less considered climate change vulnerability as a potential driver. Hence, this study is aimed to assess LULCC drivers in more fragile and dynamic landscapes of the East African Rift Valley region for the period of 1986-2016. We used a combination of Remote Sensing, Geographic Information System, logistic regression, and descriptive statistics to quantify and analyze the data. Image analysis results indicated that during the overall study period (1986-2016), grass/grazing land, agricultural land, and bare land have increased by 124%, 42%, and 34% respectively, whereas scattered acacia woodland, bush/shrubland, and swampy/marshy land have declined by 52%, 50%, and 31%, in that order. This image-derived change trend is in line with farmers’ perceived results. The top most influential drivers of LULCC includes population growth (95%), fuelwood extraction (93%), agricultural land expansion (92%), charcoal making (92%), climate change/recurrent drought (79%), and overgrazing (71%) in descending order of percentage of respondents. Education level and age of farmers significantly (p<0.05) affected their perception towards less perceived drivers. Hence, in order to reduce the adverse socio-environmental impacts of spectacular LULCC in the region, policy and decision makers need to take into account such principal drivers, particularly population growth and climate change.

Journal ArticleDOI
TL;DR: In this paper, the effects of magnetic field inclination on fluid flow and heat transfer in a two-dimensional square cavity are analyzed numerically, where the vertical walls are well insulated, the bottom wall is maintained at a cold temperature, while the top moving lid is kept at a hot temperature.
Abstract: Effects of magnetic field inclination on fluid flow and heat transfer in a two-dimensional square cavity are analyzed numerically. The vertical walls are well insulated, the bottom wall is maintained at a cold temperature, while the top moving lid is kept at a hot temperature. The finite volume method and SIMPLE algorithm are employed to solve the dimensionless governing equations. The results are presented by the profile of streamlines and isotherms, and the variation of Nusselt number. Mixed convection flow is retarded by the presence of the magnetic field and the average Nusselt number is an increasing function of the magnetic field angle.

Journal ArticleDOI
TL;DR: In this article, a study was conducted to assess the changes in plant growth, osmoprotectants, chlorophyll pigments and activities/levels of antioxidative system in spinach (Spinacea oleracea L.) grown under varying water deficit regimes with 40, 60, 80, 80% and 100% field capacity (FC).
Abstract: It is known that leafy vegetables including spinach (Spinacea oleracea L.) contain relatively high amount of water, therefore, their water requirement during the life cycle is comparatively more than the other vegetables. In addition, there is an association between osmoprotection and antioxidants with reference to drought stress tolerance. Keeping in mind these facts, the present study was conducted to assess the changes in plant growth, osmoprotectants, chlorophyll pigments and activities/levels of antioxidative system in spinach (Spinacea oleracea L.) grown under varying water deficit regimes with 40%, 60%, 80% and 100% field capacity (FC). Imposition of varying water regimes significantly decreased shoot and root fresh and dry weights, shoot plus root lengths, and chlorophyll b contents of spinach plants. Increase in proline, glycinebetaine (GB), total phenolics, ascorbic acid and malondialdehyde (MDA) contents as well as the activities of antioxidant enzymes including superoxide dismutase, peroxidase and catalase were observed in the spinach plants particularly at 40% FC. The most effective level of water stress for elevating the proline, GB and antioxidant levels/activities was observed at 40% FC followed by 60% FC. Hence, the results of this study suggested that upregulation of antioxidants and osmoprotectants is positively associated with the drought tolerance of spinach which depends on the severity of water stress level. These results can be used to narrow the gap between selection of plant species and requirement of irrigated water for the crops grown on dry land areas.

Journal ArticleDOI
TL;DR: In this paper, a microemulsion system of coconut oil with Tween 80 produced the largest micro-emulsion region compared to Tween 40 and Tween 20, and propylene glycol as a co-surfactant (CoS).
Abstract: Coconut oil in microemulsion is a better option than conventional practice since it can incorporate bioactive ingredients with a stable control release property, especially for hair care products. This work aims to develop microemulsion systems based on coconut oil with the addition of Tween 20, Tween 40, and Tween 80 as non-ionic surfactants (S), and propylene glycol as a co-surfactant (CoS). The determination of microemulsion regions in the ternary phase diagram was carried out by water titration method and the properties of the microemulsion were analysed. Based on the results, the microemulsion system of coconut oil with Tween 80 produced the largest microemulsion region compared to Tween 40 and Tween 20. Microemulsion systems of coconut oil/Tween 80 with the addition of propylene glycol with the ratio of S/CoS at Km = 3:1, 2:1, and 1:1 resulted in a decrement of microemulsion regions compared to using merely Tween 80. The microemulsion system of coconut oil/Tween 80/water at the ratio of oil: surfactant = 1:9 was chosen for further characterisations. Viscosity and electrical conductivity studies showed that the microemulsion system was water-in-oil (w/o) type as there was no phase transition to bicontinuous (BC) or oil-in-water (o/w) type due to low percentage of water content. Stability studies showed that the microemulsion system remained clear and stable at 25 and 40°C upon one-month storage except at 4°C where the system became cloudy and turbid. For particle size analysis, the microemulsion system possessed particle size less than 100 nm.

Journal ArticleDOI
TL;DR: In this article, the authors measured beetle diversity and distribution pattern along elevations at Fraser's Hill, a pristine tropical forest in Malaysia, using two light traps, two Malaise traps and 25 pitfall traps at each elevation.
Abstract: This study measures beetle diversity and distribution pattern along elevations at Fraser’s Hill, a pristine tropical forest in Malaysia. Sites were sampled at 500 m, 1000 m, 1500 m and 1800 m a.s.l. using two light traps, two Malaise traps and 25 pitfall traps at each elevation. Sampling was carried out at three months’ intervals in 2015. Altogether, 1981 beetles representing 32 families and 116 species were collected, with proportion of obtained species above 70% at all elevations. Species richness was not significant among elevations, thus forming no discernible pattern of species distribution. Higher Shannon diversity increased steadily with elevation and dominance was lowest at the two highest elevations, while beetle abundance decreases significantly with elevation. There was no significant difference between the diversity values at 500 m and 1000 m, and 1500 m and 1800 m, whereas there was significant difference between 500 m and 1500 m, and 1000 m and 1800 m. The results highlight the importance of different microhabitats for different beetle species and their own responses to environmental parameters that differ with altitudinal clines. These findings also highlight the importance of Fraser’s Hill as a key location for biological conservation and as protected area.

Journal ArticleDOI
TL;DR: In this article, the preparation of ZnO nanorod using hydrothermal method and the fabrication of NN-based field effect transistor (FET)-based biosensor have been discussed.
Abstract: Zinc oxide is a unique n-type semiconducting material, owing to wide bandgap of ~3.37 eV, non-toxic, bio-safe and biocompatible with high isoelectric point of ~9.5, make it as promising biomaterial to be utilized as sensing matrix in biosensor applications. In addition, ZnO that possess high electron affinity provide a good conduction pathway for the electrons hence result in significant electrical signal change upon detection to target biomolecules. Moreover, high surface area of ZnO nanorod enhance immobilization of enzymes, hence, increase the device performance. Field effect transistor (FET)-based biosensor offer simplicity in handling and label-free, has also become research topic among researchers for novel biosensor development. This review aims to explore the preparation of ZnO nanorod using hydrothermal method and investigate the fabrication of ZnO nanorod-based FET biosensor. Thus, contribute to enhance understanding towards biosensor development for health monitoring, especially based on FETs structure devices.

Journal ArticleDOI
TL;DR: In this paper, a limonene-based microemulsion system as vitamin C carrier was produced using tween20 and tween80 as surfactants while propylene glycol, polyethylene glycol 400 and glycerol as co-surfactants.
Abstract: This research was conducted to produce a limonene-based microemulsion system as vitamin C carrier. The microemulsion was produced using limonene as the oil phase, tween20 and tween80 as surfactants while propylene glycol, polyethylene glycol 400 and glycerol as co-surfactants. Pseudo-ternary phase diagrams were constructed to determine the microemulsion area by using the water titration method at 25°C. The effect of hydrophilic-lipophilic balance (HLB) value of the mixture of S/CoS on the formation of limonene-based microemulsion was studied. The HLB value calculated for the mixture of tween20/propylene glycol in the different ratio was between 10.1 and 13.4. From the experiment, the preparation of limonene-based microemulsion system with tween20/propylene glycol was able to provide large and high stability of microemulsion region on ternary phase diagram (23.6%) while higher HLB value resulted in larger microemulsion area in ternary phase diagrams. The sole formulation with propylene glycol was further selected to carry out the physicochemical characterization of system’s stability, particle size and electrical conductivity. All microemulsion systems showed good stability for four weeks at temperature of 4, 25 and 40°C without any phase change and separation. Particle size characterization results elucidated that all microemulsion systems consisted particle size between 20 and 100 nm. The study of electrical conductivity showed that water-in-oil microemulsion was formed from 5-45% wt. of water whereas bicontinuous microemulsion was formed from 50-90% wt. of water content. Overall, the result showed that microemulsion tween20/propylene glycol/limonene/water was potential as a carrier system of vitamin C.

Journal ArticleDOI
TL;DR: In this article, the optical refractive indices of different molarities of glucose using nano-laminated gold/chromium (Au-Cr) thin film via Kretschmann-based surface plasmon Resonance (K-SPR) sensing with angular interrogation were determined.
Abstract: In this paper, we determine the optical refractive indices of different molarities of glucose using nano-laminated gold/chromium (Au-Cr) thin film via Kretschmann-based Surface Plasmon Resonance (K-SPR) sensing with angular interrogation. The nano-laminated Au-Cr K-SPR sensor detects the glucose presence in low- and high-concentration of 4-12 mmol/L and 55-277 mmol/L, respectively, under the exposure of 670 nm and 785 nm optical wavelengths. The experimental results showed that the minimum limit of detection (LOD) of Au-Cr K-SPR is 4 mmol/L and the glucose sensor sensitivities are in average of 3.41 o/M and 2.73o/M at 670 nm and 785 nm optical wavelength, respectively. Stable sensitivity for each concentration also shown from the sensorgram results, indicates the stable performance of nano-laminated Au-Cr SPR sensor to detect glucose in the range from mmol/L up to dmol/L. Values of refractive indices for glucose molarities obtained are 1.33187 (4 mmol/L) and 1.3191 (4 mmol/L) at 670 and 785 nm wavelength, respectively. These RI values are beneficial for numerical simulation of glucose sensors using nano-laminated Au-Cr thin films which have been reported for the first time. The sensor can be eventually deployed in integrated photonic sensing devices comprising of multiple analyte detection for lab-on-chip (LoC) and point-of care (PoC) applications.

Journal ArticleDOI
TL;DR: Findings show that lufenuron can be a potential product for pest management in mills, warehouses and food storage facilities.
Abstract: Red flour beetle, Tribolium castaneum is a serious pest of stored grain commodities. A laboratory study was conducted for evaluating the sub-lethal effects of a chitin synthesis inhibitor, lufenuron at concentrations of 0.02, 0.04 and 0.08 ppm against two strains of T. castaneum. Lufenuron caused significant effects on larval mortality, larval duration before pupae, larval weight, pupae and adult emergence. When these adults were allowed to oviposit on untreated wheat flour, their fecundity and egg hatchability was reduced to a larger extent at all the tested concentrations as compared to control treatment. Further, subsequent development of F1 larvae, pupae and adults were also severely prohibited. Our findings show that lufenuron can be a potential product for pest management in mills, warehouses and food storage facilities.

Journal ArticleDOI
TL;DR: In this article, the authors discuss on cellulose and its derivatives, and methods to produce cellulose fibres and nanofibres, and summarise cellulose in terms of a matrix of cellulose, solvent, parameter electrospinning, fibre diameter and their perspective applications.
Abstract: Cellulose fibres and nanofibres have gained interest because of the high strength and firmness, biodegradability and renewability. The enthusiasm in cellulose and its modification as cellulose-derivative has been exponentially expanding. This paper discuss on cellulose and its derivatives, and methods to produce cellulose fibres and nanofibres. Emphasis is given on electrospinning technique, the most utilised technique to produce cellulose fibres and cellulose nanofibres with ranging from nanometer to millimeter in diameter. It also summarises cellulose in terms of a matrix of cellulose, solvent, parameter electrospinning, fibre diameter and their perspective applications.

Journal ArticleDOI
TL;DR: In this article, the morphology, microstructure, and mechanical properties of Pineapple leaf fibres were investigated and it was found that the fibres obtained from vascular tissue and from the mesophyll have different macroscopic shapes.
Abstract: Pineapple leaf waste is an agricultural product that is available in large quantities and is still under-utilized. Therefore, the aim of this work was to investigate the morphology, microstructure, and mechanical properties of pineapple leaf fibre (PALF) such that its full potential may be realized. Pineapple leaf, its fibre bundles and elementary fibres have been investigated. Morphology, size, and mechanical properties of fibre bundles extracted from different parts (i.e. bottom, middle and top) of a leaf were studied. It was found that the PALF obtained from vascular tissue and from the mesophyll have different macroscopic shapes. Both, however, contain micron-size elementary fibres of similar size and shape. Size and properties of fibre bundles change from the bottom end of a leaf toward the top end. Pineapple leaf microfibre (PALMF) was found to be smaller in diameter than other natural fibres. It is also very long and its structure changes according to its position along the leaf. At the bottom end a clear and large central hole or lumen can be observed. At the top the lumen becomes almost undetectable. The mechanical strength of PALMF appears to decrease, albeit very slightly, toward the tip of the leaf. The mechanical properties of the fibres are relatively high and comparable to that of flax and hemp fibres which are widely studied and used as reinforcing materials in composites. Very long microfibre can easily be obtained from fibre bundles by dissolving the binding matrix. Potential applications for this microfibre are suggested.

Journal ArticleDOI
TL;DR: In this paper, the effects of soft clay soil on soil organic carbon content, stock and change rate were investigated in Alor Senibong paddy field area in Kedah, Malaysia.
Abstract: Soft clay soil has become a major problem in paddy cultivation area. Nearly half of the total paddy field in Kedah State, Malaysia cannot be utilized for paddy cultivation because of soft clay soil. The problem is related to the presence of weak hardpan structure that permits the soil to experience continuous wet condition. The soil also causes in the alteration of many processes soil organic carbon sequestration and turnover, but the main effect on the land is decrease in soil fertility. To investigate the effects of soft clay soil on soil organic carbon content, stock and change rate, the trial has been conducted in Alor Senibong paddy field area in Kedah, Malaysia examining the problematic paddy field that associated with soft clay soil problem. Hasil Tani Organic Compound (HTOC) was an organic soil amendment that used to enhance soil organic carbon in this study. Paddy field with the presence of soft clay soil showed a low soil organic carbon content and stock around 0.67% and 1.01 t·ha-1, respectively (depth 0-15 cm). The reduction of soil organic carbon content in soft clay soil was likely because of the waterlogged soil environment, the stability of soil aggregates and decline in humification process which then reduced soil organic carbon input. After being treated with HTOC, soil organic carbon content and carbon stock in soft clay soil have significantly increased by 0.67-3.14% and 1.01-4.76 t·ha-1 (depth 0-15 cm), respectively, yielding a mean monthly carbon change rate of 4.36 g C kg−1·mth.−1 (depth 0-15 cm). As whole, the succession of HTOC application to improve soil organic carbon content in this study could be employed in other paddy field areas that associated with soft clay soil problem.

Journal ArticleDOI
TL;DR: In this article, a 2-point block backward differentiation formulas (BBDF) of order 3, 4, and 5 for direct solution of second order ordinary differential equations were derived via backward difference interpolation polynomial with two solutions are produced simultaneously at each step.
Abstract: This paper proposed 2-point block backward differentiation formulas (BBDF) of order 3, 4, and 5 for direct solution of second order ordinary differential equations. These methods were derived via backward difference interpolation polynomial with two solutions are produced simultaneously at each step. All the three different orders of 2-point BBDF is implemented in variable order scheme. The scheme utilizes the local truncation error, which is generated by the single order of 2-point BBDF method. Numerical results are presented to illustrate the validity of the proposed scheme.

Journal ArticleDOI
TL;DR: Pengekstrakan torium daripada larutan akueus torium tetraklorida (ThCl4) telah dilakukan dengan menggunakan larutan organik Di-(2-etikheksil) asid fosforik dalam kerosen (D2EHPA/K).
Abstract: Pengekstrakan torium daripada larutan akueus torium tetraklorida (ThCl4) telah dilakukan dengan menggunakan larutan organik Di-(2-etikheksil) asid fosforik dalam kerosen (D2EHPA/K). Objektif kajian ini adalah untuk menentukan parameter kepekatan organik dalam pelarut dan masa campuran optimum yang mempengaruhi kecekapan pengekstrakan. Campuran torium - nadir bumi hidroksida ([Th-RE](OH)4) daripada sumber kepekatan monazit tempatan dilarutkan dalam asid hidroklorik (HCl) pada kepekatan 3 dan 4 molariti. Larutan akueus [Th-RE](OH)4 ini dicampurkan dengan pelarut organik D2EHPA/K pada kepekatan berbeza iaitu 10%, 20% dan 30%. Sebatian diaduk selama 5 hingga 20 min sebelum fasa larutan akueus dan organik dipisahkan. Kepekatan torium sebelum dan selepas pengekstrakan dianalisis menggunakan Spektrometri Jisim Plasma Gandingan Teraruh (ICP-MS). Keputusan kajian mendapati peningkatan kepekatan torium dalam larutan akueus (Th-RE)OH4 dalam julat 119.40 ± 3.43 – 121.13 ± 3.18 ppm berbanding sebelumnya. Kecekapan pengekstrakan optimum bagi torium ialah 99.8%, menggunakan D2EHPA/K pada kepekatan 30%. Keputusan kajian juga mendapati masa optimum bagi proses campuran dan pemisahan torium dalam larutan akueus kepada fasa organik masing - masing adalah 5 min. Sehubungan dengan itu, kajian ini membuktikan D2EHPA berpotensi untuk digunakan sebagai agen pengekstrakan torium daripada larutan asid hidroklorik.

Journal ArticleDOI
TL;DR: Patients with diabetes observed more barriers than facilitators to implementing healthy lifestyle changes, and the two main themes generated from this review are intrinsic factors and extrinsic factors that can either be facilitators or barriers to implementing lifestyle change.
Abstract: Type 2 diabetes is a non-communicable disease that affects most people around the world and is generally the result of excessive food intake and physical inactivity. Therefore, the purpose of this review was to identify facilitators and barriers for lifestyle modifications among type 2 diabetes patients. We combined quantitative and qualitative studies for this systematic narrative review. A literary search was carried out using EBSCO, HighWire Press, Medline, PsycInfo, PubMed and Scopus. Narrative review was used to extract results from quantitative studies, while thematic synthesis was used to extract results from qualitative studies. Twenty-three studies were included in this review, with a total of 2287 participants from Western, Arab and Asian populations. The two main themes generated from this review are intrinsic factors and extrinsic factors that can either be facilitators or barriers to implementing lifestyle change. Among the barriers faced by the participants are established food habits, lack of self-efficacy, lack of motivation, lack of social support, inadequate knowledge, low socio-economic status, food culture and poor time management. In contrast, the facilitating factors generated are strong self-efficacy, high motivation, good habits, and sufficient knowledge. In general, patients with diabetes observed more barriers than facilitators to implementing healthy lifestyle changes.

Journal ArticleDOI
TL;DR: In this paper, the growth promoting effects of lignosulfonate (LS) on callus proliferation and shoot induction of Malaysian recalcitrant indica rice cv. MR219 were evaluated.
Abstract: In vitro culture of recalcitrant indica rice cultivar through intervening callus is difficult due to long regeneration period. Therefore, this study was undertaken to evaluate the growth promoting effects of lignosulfonate (LS) on callus proliferation and shoot induction of Malaysian recalcitrant indica rice cv. MR219. LS is a by-product of wood industry, commonly used as a plant growth enhancer. Seed derived calli were proliferated on Murashige and Skoog (MS) medium supplemented with different ion-chelated LS (calcium LS: CaLS and sodium LS: NaLS) at 50, 100, 150, and 200 mg/L. MS supplemented with 100 mg/L CaLS significantly increased the callus proliferation rate and adventitious root formation. In shoot induction study, both LSs did not enhance the shoot induction efficiency as compared to the control. However, the formation of albino shoot increased in MS fortified with 100 mg/L CaLS. Further chlorophyll and molecular analyses showed that, albino shoots induced from 100 mg/L CaLS had severe reduction in total chlorophyll content and expression of both chlorophyll-associated genes, chlorophyll a/b-binding protein 1 (OsCAB1R) and young seedling albino (OsYSA). Taken together, LS improves callus proliferation rate and modulate different physiological responses during plant growth of recalcitrant indica rice.

Journal ArticleDOI
TL;DR: The preliminary result showed that stroke patients are particularly at risk of malnutrition or malnourished during the rehabilitation period, and early identification of malnutrition for stroke patients is important for a successful rehabilitation program.
Abstract: Malnutrition is highly prevalent among stroke patients during post-acute rehabilitation phase and may give a negative effect on rehabilitation and impair recovery. However, to date, there is no reported study in Malaysia investigating the nutritional status of stroke patients during rehabilitation phase. Thus, this paper aims to report the preliminary results of nutritional assessment for a randomized controlled trial at baseline. All participating patients were assessed for anthropometric measurements, nutritional status using validated Mini Nutrition Assessment (MNA), 24 h diet recall, and handgrip strength. Demographic data, biochemical profiles and functional outcomes (Modified Barthel Index Score, Motor Assessment Scale) were obtained from patients’ medical record. From a total of 45 post-acute stroke patients at baseline, 24.4% of them were malnourished during admission to rehabilitation ward and 66.7% of the patients were at risk of malnutrition. Mean dietary intake and protein intake of the patients were 1489 ± 297 kcal/day and 66.1 ± 17.2 g/ day, respectively. Mean handgrip strength for the patients was 17.9 ± 8.1 kg. Weight, body mass index, serum albumin, handgrip strength, Modified Barthel Index and Motor Assessment Scale score were positively correlated with MNA score (p<0.05), but no correlation was found for the dietary intake (r=0.163, p=0.285) and protein intake (r=0.288, p=0.055). This preliminary result showed that stroke patients are particularly at risk of malnutrition or malnourished during the rehabilitation period. Therefore, early identification of malnutrition for stroke patients is important for a successful rehabilitation program. © 2019 Penerbit Universiti Kebangsaan Malaysia. All Rights Reserved.