It is important to monitor the concentration of toxic metals in the Sungai Kuantan as it serves many communities in terms of domestic, fisheries and agriculture purpose. In order to determine the distributions of dissolved and particulate As and Hg in Sungai Kuantan and evaluate its changes temporally and spatially, water samples were collected from the surface and bottom layers in a grid of 9 stations from estuary towards the upstream of Sungai Kuantan from May 2012 till October 2012. The dissolved metals were pre-concentrated using Chelex-100 while particulate metals were digested using Teflon bomb and subsequently were analyzed using ICP-MS. Dissolved As ranging from 4.650 to 36.894 µg L-1 while dissolved Hg ranging from BDL to 0.011 µg L-1. Particulate As and Hg varied from 0.650 to 86.087 mg L-1 and BDL to 5.873 mg L-1, respectively. Higher concentration of the dissolved elements were found mainly in October 2012 and particulate elements concentration mostly higher in May 2012. The source of the studied metals in the river may be the run-off from the effluent discharges and other natural sources. The toxic elements studied in Sungai Kuantan waters were still below the Interim Marine Water Quality Standard (INWQS) permissible limits.
Ash and sulphur are the two main variables that influence coal quality and are therefore very important contractual
parameters in a coal supply agreement. Coal which is low in ash yield and sulphur content is considered as ‘cleaned
coal’. Nonetheless, combustion of coal is also known to release toxic trace elements, which are known or suspected to
be carcinogenic and may also cause respiratory problems, pregnancy complications, premature mortality and possibly
a wide range of health problems. The two traditionally used coal quality parameters have proven to be insufficient for
defining ‘cleaned coal’. This is evidenced by the low ash and low sulphur Balingian coals that is seen as relatively safe
in environmental terms, but still contains high concentrations of potentially hazardous trace elements which may pose
health and environmental threats during coal combustion. Therefore, a comprehensive assessment of coal quality should
also include information on concentration, spatial distribution and modes of occurrence of trace elements, particularly
the 15 potentially hazardous trace elements identified by the United States Clean Air Act Amendments (1990).
This study presents the optimum cutting ages in Turkish pine (Pinus brutia Ten.) plantations including timber production
and carbon sequestration values in Turkey. Four different growing spaces are considered. The study also evaluates the
effects of different discount rates and carbon prices on the optimum cutting ages using net present value approach. The
growth and yield curves, biomass equations and carbon conversion factors as well as forest plantation costs and timber
assortments revenues for Turkish pine plantations are used to determine the optimum cutting ages. The results of the
case study showed that the integration of carbon sequestration benefits into timber production increased the optimum
cutting ages of Turkish pine plantations for each growing spaces in order to sequester more carbon. The optimum cutting
ages decreased depending on the increase in discount rates. When carbon prices increased the optimum cutting ages
also increased.
The Sidoarjo mud is the first visible phenomenon of a mud volcano that occurs in a human settlement and which is
subsequently channelled into a river. Clay, aluminium and iron were reported to be the dominant contaminants that could
possibly come into contact with and accumulate on the surface of local fish and initiate alteration in scale microstructure.
The aim of this study was to evaluate the extent of water body contamination in the Sidoarjo mud by evaluating the
chromatophore density and microstructure deformation of fish scales that act as biomarkers. Scale samples were
obtained from caged Mozambique tilapia (Oreochromis mossambicus) fish that were placed downstream and upstream
of the Sidoarjo mud spillway pipes. With respect to melanophore density, it was found that the scales of fish exposed in
the downstream section were significantly lower in chromatophores (<50 chr/mm²) than the control scales in fish from
the upstream station (>100 chr/mm²). This study suggested that the density of chromatophores was closely related to
the concentration of total suspended solids (r = 0.69), which was possibly enhanced by iron (r = 0.56). Using scanning
electron microscopy analysis, some deformation, i.e. irregularity of spherule shape and increasing pits in the space
between ridges, were observed.
A study was conducted in the mudflats of Jeram and Remis Beaches, Selangor, Peninsular Malaysia from November 2013
until July 2014 to determine the effects of disturbance on shorebird and waterbird abundance and foraging behavior. Direct
observation was used in this study. Mann-Whitney test showed no significant difference in abundance of bird in Jeram
and Remis Beaches (t=2.96, p=0.05). A significant difference were detected between the sampling plots in Jeram Beach
(S=16.67, p<0.001) and Wilcoxon Signed Rank Test shows a significant difference between the sampling plots in Remis
Beach (W=78, p=0.003). Spearman’s rank correlation shows significant association between the abundance of bird with
the abundance of humans, dogs and vehicles (p<0.05) in both Jeram and Remis Beaches. Humans contribute to a higher
percentage in disruptions towards the species studied (47.5%), followed by dogs (32.1%) and vehicles (20.4%). Thirtysix
percent of birds stopped feeding and flew away upon disruption, 23% stopped feeding and run away, 22% stopped
feeding but stay alert and 19% continue feeding (habituated). Analysis on the responses of birds toward the disturbance
show significant difference between species (χ2
= 98.77, p<0.05). This study concluded that anthropogenic disturbance
caused a major impact on shorebird and waterbird abundance and influenced their foraging behavior. Response of bird
towards disturbance was varied according to the species and types of disturbance. By understanding how the bird species
response toward disturbance, the conservation efforts can be implemented more effectively in the future.
Sap flow pattern of Tectona grandis planted at lowland forest assessed. This study aimed to determine the sap movement
of two different diameter sizes T. grandis. Two sizes selected were 16 and 38 cm in diameter at breast height (dbh). Sap
flow meter (SFM) used to assess the sap velocity rates at the interval of 30 min within 24 h for 15 days. Diurnal sap flow
of T. grandis shows that mean velocity is high during day time compared night time. Small diameter has high sap flow
compared to that of bigger diameter. A flow rates was high at the inner layer and less at outer layer for smaller tree. The
variation was vice versa when the tree was getting bigger. Variations in sap flow of T. grandis characterized by several
environmental factors. It was found that size contribute in the differed sap flow of T. grandis.
The paper aims at studying forced convection in a viscous incompressible electrically conducting fluid along stretching sheet with variable thickness in the presence of variable free stream and magnetic field. The governing equations of flow and heat transfer are subjected to similarity transformation using boundary layer assumption and are then solved numerically. The system of equations possesses dual solutions for negative value of velocity power index (m). The impact of velocity parameter (λ) and other parameters on velocity and temperature distributions, skin friction and heat transfer are studied when system possesses dual solutions and is presented through graphs and discussed suitably. It is found that the first solution is in tune with natural physical phenomena. The second solution possesses very large skin-friction and fluid velocity as compared to the first solution. The second solution is stable and is a mere outcome of non-linearity and does not follow natural phenomena.
In this study, a novel matrix method based on collocation points is proposed to solve some linear and nonlinear integro-differential equations with variable coefficients under the mixed conditions. The solutions are obtained by means of Dickson and Taylor polynomials. The presented method transforms the equation and its conditions into matrix equations which comply with a system of linear algebraic equations with unknown Dickson coefficients, via collocation points in a finite interval. While solving the matrix equation, the Dickson coefficients and the polynomial approximation are obtained. Besides, the residual error analysis for our method is presented and illustrative examples are given to demonstrate the validity and applicability of the method.
Missing value problem is common when analysing quantitative data. With the rapid growth of computing capabilities, advanced methods in particular those based on maximum likelihood estimation has been suggested to best handle the missing values problem. In this paper, two modern imputing approaches namely expectation-maximization (EM) and expectation-maximization with bootstrapping (EMB) are proposed in this paper for two kinds of linear functional relationship (LFRM) models, namely LFRM1 for full model and LFRM2 for linear functional relationship model when slope parameter is estimated using a nonparametric approach. The performance of EM and EMB are measured using mean absolute error, root-mean-square error and estimated bias. The results of the simulation study suggested that both EM and EMB methods are applicable to the LFRM with EMB algorithm outperforms the standard EM algorithm. Illustration using a practical example and a real data set is provided.
MeSH terms: Algorithms; Likelihood Functions; Linear Models
Poly(N-isopropylacrylamide) (PNIPA) brushes on silicon substrate was constructed and molecular weight and polydispersity index was controlled precisely. Molecular behavior of the PNIPA grafted surface was observed by using captive bubble contact angle method. A very interesting phenomenon of high density PNIPA grafted membrane with a chloride terminal molecule was observed. The contact angle of high density PNIPA-Cl increased sharply while the temperature rises above 32oC. But in the case of PNIPA gel surface the contact angle result decreases sharply while the temperature reaches above lower critical solution temperature (LCST). In order to identify the reason behind this abnormal behavior of PNIPA-Cl grafted membrane, the terminal chloride molecule of PNIPA chain was modified to less electronegative azide (-N3) as well as carboxylic acid (-COOH). Finally it was found that terminal molecule of high density PNIPA grafted membrane has a great influences on the wettability change of PNIPA membrane in water by changing the temperature.
Sn-Ag based solder alloy seems to be a promising lead-free solder for the application on electronic assembly. The corrosion behavior of different lead free solder alloys such as Sn-3.0Ag, Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu was investigated in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to characterize the samples after the tests. The results showed that the addition of 0.5 wt. % copper with Sn-3.0 Ag solder alloy led to a better corrosion resistance while lowering of Ag content from 3.0 to 1.0 wt. % decreased the resistance. Sn-3.0Ag-0.5Cu exhibits a better corrosion resistance in terms of increased charge transfer resistance and impedance values as well as the lowest capacitance. These characteristics signify its suitability for the application in electronic packaging.
MeSH terms: Alloys; Copper; Corrosion; Drug Packaging; Microscopy, Electron, Scanning; Spectrometry, X-Ray Emission; X-Ray Diffraction; Electric Impedance; Product Packaging; Electric Capacitance; Dielectric Spectroscopy
316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.
Toluene and benzene are hazardous air pollutants commonly found in the atmosphere at relatively high concentrations. Due to this, a need to remove these pollutants became a necessity. In this study, octahedral molecular sieve type manganese oxide (K-OMS 2) prepared by hydrothermal method was utilized to decompose toluene and benzene. X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmet-Teller (BET), X-ray absorption near edge structure (XANES) analysis were used to investigate the crystallinity, morphology, surface area and oxidation state of K-OMS 2, respectively. It was confirmed that K-OMS 2 was successfully produced from hydrothermal method. Central composite design (CCD) was used to investigate the main and interaction effects of gas hourly space velocity (GHSV) and reaction temperature on the thermal catalytic oxidation of benzene and toluene. Both factors were found to have significant main and interaction effects on toluene oxidation. However, only the main effects of the factors were significant for benzene. This result was due to the difference in the stability of the structures of the two VOCs. The K-OMS 2 obtained has excellent efficiency on toluene and benzene removal. Toluene was completely decomposed at a temperature as low as 250°C while benzene decomposition reached around 98% at 292.4°C.
Factories and Machinery (Noise Exposure) Regulation 1989 has always demanded employer to protect workers from noise exposure ≥85 dB. However, noise induced hearing loss (NIHL) has been the highest notifiable occupational health issue among Malaysian workers in 2014. A cross-sectional study aimed to investigate the prevalence of hearing loss (HL) among 146 adult manufacturing workers with noise exposure ≥85 dB was carried out in Selangor. Pure tone audiometry and a validated questionnaire were used to determine the hearing status and information of the respondents. The results showed that the prevalence of HL was 73.3% and the prevalence of hearing impairment was 23.3%. Male workers (63.0%) had higher prevalence of HL than female workers (36.4%). Mean hearing threshold levels of HL respondents were significantly higher than respondents with normal hearing. It was discovered that among workers with employment of more than 10 years, > 80% of them suffered from HL. Association between employment years and hearing condition (normal, non-bilateral and bilateral HL) was statistically significant, χ(4)= 10.51, p=0.033, with Kendall tau-c correlation showing positive and weak (p=0.18) association. Highest HL cases were found at 4 and 6 kHz. World Health Organisation and Factories and Machinery (Noise Exposure) Regulation 1989 classification on degree of hearing impairment showed slight to moderate hearing impairment among the respondents and both standards did not differ much (8.9% vs 6.9%, respectively). As a conclusion, prevalence of hearing loss and hearing impairment among manufacturing workers were high. Age, male sex, monthly salary and employment years were possible influencing factors.
Dengue fever is considered as one of the most common mosquito borne diseases worldwide. Dengue outbreak detection can be very useful in terms of practical efforts to overcome the rapid spread of the disease by providing the knowledge to predict the next outbreak occurrence. Many studies have been conducted to model and predict dengue outbreak using different data mining techniques. This research aimed to identify the best features that lead to better predictive accuracy of dengue outbreaks using three different feature selection algorithms; particle swarm optimization (PSO), genetic algorithm (GA) and rank search (RS). Based on the selected features, three predictive modeling techniques (J48, DTNB and Naive Bayes) were applied for dengue outbreak detection. The dataset used in this research was obtained from the Public Health Department, Seremban, Negeri Sembilan, Malaysia. The experimental results showed that the predictive accuracy was improved by applying feature selection process before the predictive modeling process. The study also showed the set of features to represent dengue outbreak detection for Malaysian health agencies.
Polygonum minus is a plant rich in flavonoids and antioxidants beneficial for reducing oxidative stress and lipid peroxidation in neuronal membranes. This randomized, double-blind, placebo-controlled study evaluated the potential benefits of P. minus extract (LineMinusTM) towards improving cognitive function, mood status and quality of life. Thirty five middle-aged women (35-55 years old) were randomized into intervention (n=17) and control group (n=18). Two capsules of P. minus (250 mg) or placebo (100 mg maltodextrin) each were taken once daily for six weeks. Cognitive tests, mood and anthropometric measurements were measured at baseline, week 3 and week 6, whilst biomarkers were measured at baseline and week 6. Parameters related to mood and quality of life including energy/fatigue, social functioning and general health significantly improved from baseline to week 6 in the intervention group (p<0.05). Mean score for cognitive tests (i.e. digit span, comprehensive trail making test (CTMT) and three domains of CNS vital sign (CNSVS)] improved significantly in both intervention and control groups (p<0.05). There was a significant decrease of mean uric acid, estimated glomerular filtration rate (eGFR), total cholesterol and glycated hemoglobin (HbA1C) in the intervention group from baseline to week 6. P. minus supplementation has the potential to improve mood and quality of life and no adverse effects were reported by the participants after 6 weeks supplementation.
MeSH terms: Affect; Antioxidants; Capsules; Cholesterol; Cognition; Double-Blind Method; Female; Flavonoids; Glomerular Filtration Rate; Humans; Middle Aged; Polysaccharides; Quality of Life; Trail Making Test; Uric Acid; Lipid Peroxidation; Biomarkers; Oxidative Stress; Polygonum; Control Groups
The experiments were carried out to evaluate the protein-sparing effect in Heteropneustes fossilis fry (0.751 ± 0.01 g) fed for 90 days with six isocaloric diets containing 45, 40 or 35% of casein-protein and 25, 30 or 35% of glucose/dextrin, combined properly as the work purpose. The highest weight gain was recorded in fry fed with 35% dextrin and 35% crude protein level. Interestingly, the value of SGR (2.950±0.017) and PER (1.793±0.03) were significantly (p<0.05) increased with reducing protein level from 45 to 35% and with increasing carbohydrate level from 25% to 35%, respectively. However, the poorest growth was recorded in the fry fed with glucose containing diets than dextrin-containing diets. Protein deposition was significantly (p<0.05) lower in fry fed with the glucose diets at the protein level of 45% than those fed with 40 or 35%, indicating that H. fossilis utilize dextrin easily than glucose. Increase of dextrin content from 35 to 45% did not reduce (p<0.05) the weight gain, even reducing the dietary protein from 45 to 35%. This fact suggests that carbohydrate spare protein by using dextrin as energy source.
This study aimed to extract carotenoids from pumpkin (Cucurbita moschata) by using food grade solvents (ethanol, ethyl acetate, acetic acid and virgin coconut oil). The influence of different extraction conditions; temperature of extraction (15, 30 and 45℃), duration of extraction (12, 18 and 24 h) and solid to solvent ratio (1:50, 1:100 and 1:150) on yield of carotenoids were also evaluated for optimization purposes. The compounds of the extracted carotenoids were identified by using high performance liquid chromatography (HPLC). The detected carotenoids from pumpkin had been α-carotene, β-carotene and lutein. Lutein was found to have the highest concentration in pumpkin. Furthermore, the results obtained from the yield of carotenoids showed that sample extracted with ethyl acetate was insignificant and this differed from that with virgin coconut oil extract (77.30 and 76.64 β-carotene μg/g dry matter, respectively). Meanwhile, the samples extracted by using either acetic acid or ethanol had presented low yields (68.10 and 54.98 β-carotene μg/g dry matter, respectively). Nevertheless, the extract of carotenoids was found to be optimized at the following extraction conditions; 1:150 solid to solvent ratio and extracted by using virgin coconut oil for 12 h at 30oC.
The efficacy of the combination vaccine of the individual C-terminal fragments of ApxIA, ApxIIA and ApxIIIA of Actinobacillus pleuropneumoniae (APP) was evaluated in piglets. Twenty piglets were divided equally into 2 groups (n=10). All piglets were intramuscularly primed at 4 week-of-age (0 week post prime inoculation (WPPI)) and were intramuscularly boosted at 6 week-of-age (2 WPPI). Group A piglets were inoculated with sterile PBS and group B piglets were inoculated with the combination vaccine. Concentrations of each of the C-terminal fragment-specific IgG as determined by ELISA were significantly higher in group B than in group A from 2 WPPI until the end of this study. Clinical signs were observed from only 10% of group B piglets after the challenge with the mixture of APP serotypes 1, 2 and 5 at 4 WPPI, while 50% of group A piglets were protected against APP infections. Overall, intramuscular inoculation with the vaccine candidate can efficiently protect piglets against APP infection.
A study was conducted to differentiate fractionated components of lard namely lard olein (LO) and lard stearin (LS) from other common animal fats. Lard fractions and animal fats were analyzed using differential scanning calorimetry (DSC), elemental analyzer–isotope ratio mass spectrometry (EA-IRMS), gas chromatography mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). Overlay of FTIR spectra did not help to pinpoint any characteristic feature to distinguish either LO or LS from other animal fats, but overlay of DSC cooling curves helped a successful discrimination. The determination of δ13C from EA-IRMS showed that the values corresponding to the fractionated components of lard were significantly (p<0.05) different from those of the other common animal fats. GC-MS analysis showed that direct comparison of overall fatty acid data was not able to discriminate LO and LS from other animal fats, but the application of principal component analysis (PCA) to fatty acid data helped a successful discrimination.