The study to determine the concentrations of dissolved heavy metals in the Sungai Semenyih and to use the environmetric
methods to evaluate the influence of different pollution sources on heavy metals concentrations was carried out. Cluster
analysis (CA) classified 8 sampling stations into two clusters based on the similarity of sampling stations characteristics,
cluster 1 included stations 1, 2, 3 and 4 (low pollution area), whereas cluster 2 comprised of stations 5, 6, 7 and 8
(high pollution area). Principal component analysis (PCA) of the two datasets yield two factors for low pollution area
and three factors for the high pollution area at Eigenvalues >1, representing 92.544% and 100% of the total variance
in each heavy metals data sets and allowed to gather selected heavy metals based on the anthropogenic and lithologic
sources of contamination.
Effects of radiation on free convection about a heated horizontal circular cylinder in the presence of heat generation is investigated numerically. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equations are transformed into dimensionless non-linear partial differential equations and solved by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determined the effects of radiation parameter, heat generation parameter, and the Prandtl number, on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of and are shown graphically.
MeSH terms: Body Temperature Regulation; Clothing; Hot Temperature; Temperature; Friction; Convection
A new numerical method was proposed in this paper to address the nonlinear quadratic optimal control problems, with state and control inequality constraints. This method used the quasilinearization technique and Haar wavelet operational matrix to convert the nonlinear optimal control problem into a sequence of quadratic programming problems. The inequality constraints for trajectory variables were transformed into quadratic programming constraints using the Haar wavelet collocation method. The proposed method was applied to optimize the control of the multi-item inventory model with linear demand rates. By enhancing the resolution of the Haar wavelet, we can improve the accuracy of the states, controls and cost. Simulation results were also compared with other researchers' work.
In this paper, the problem of free convection boundary layer flow on a horizontal circular cylinder in a nanofluid with viscous dissipation and constant wall temperature is investigated. The transformed boundary layer equations are solved numerically using finite difference scheme namely the Keller-box method. Numerical solutions were obtained for the reduced skin friction coefficient, Nusselt number and Sherwood number as well as the velocity and temperature profiles.The features of the flow and heat transfer characteristics for various values of the Brownian motion parameter, thermophoresis parameter, Lewis number and Eckert number were analyzed and discussed.
This study focuses on the potential of electric arc furnace (EAF) steel slag and copper mine tailings as asphalt paving materials with respect to issues of volumetric properties and leaching. In this study, four different asphalt mixes were investigated; each contained EAF steel slag and copper mine tailings of various proportions. Apart from the microstructure analysis of the materials, a toxicity characteristics leaching procedure (TCLP) test was conducted on both the mixes and the aggregates. All the mixes were evaluated by the following parameters: Voids in the mineral aggregates (VMA), voids in total mix (VTM), voids filled with asphalt (VFA), Marshall stability and flow and specific gravity. F-test ANNOVA was used to evaluate the degree of significance of the mixes with each of the evaluated standards. It was observed that the mixes containing either EAF steel slag or copper mine tailings or both gave better results than the control mix. In terms of the TCLP test, none of the detected hazardous elements exceeded the standard limits, which indicates the possibility of using them as construction materials.
MeSH terms: Construction Materials; Copper; Hydrocarbons; Minerals; Specific Gravity; Steel; Toxicity Tests
Cellulose was extracted from kenaf core pulp (KCP) by a series of bleaching processes (D) and alkali treatment (E) in the sequence of (DEED) and pretreated with acid hydrolysis in room temperature for 6 hours. The pretreated and non-treated cellulose were dissolved in lithium hydroxide/urea (LiOH/urea) and subsequently used to produce cellulose membrane cross linked with various percentages of glyoxal from 2.5 to 20%. The effects of acid hydrolysis pretreatment on solubility, crystallinity and morphology were investigated. The acid hydrolysis pretreatment leads to higher solubility of the cellulose solution. The formation of cellulose II and crystallinity index of the cellulose membrane were examined by X-ray diffraction (XRD). Cellulose membrane without acid hydrolysis pretreatment cross linked with higher percentage of glyoxal has higher tensile strength compared with the treated cellulose.
The aimed of this study was to evaluate the resistance of sesenduk (Endospermum diadenum) wood, treated using admixture
of low molecular weight phenol formaldehyde (LmwPF) resin and nanoclay, against white rot fungus (Pycnoporus
sanguineus) and subterranean termites (Coptotermes curvignathus Holmgren). Seven sample groups including untreated
sesenduk wood and treated sesenduk wood using 10, 15 and 20% LmwPF resin and the admixture of the 1.5% nanoclay
with every level of resin concentrations. Air-dried samples were impregnated using vacuum-pressure process. After
impregnation, the treated samples were heated in an oven at 150°
C for 30 min. Five test blocks from each treatment
group were tested separately against P. sanguineus and C. curvignathus in accordance with AWPA E10-12 and AWPA E1-13
standards, respectively. The results showed that both treatments had significant effects on the percentage weight loss and
decay rate of the samples. The weight loss due to termite attack was found reduce with the increasing PF concentration.
Generally, the addition of 1.5% nanoclay in PF resin slightly increased the resistance against both deteriorating agents
compared to the wood treated using PF alone. It was found that the PF resin can be used as an effective method to improve
the durability of sesenduk wood.
Glufosinate ammonium or ammonium salt (ammonium-(2RS)-2-amino-4- (methylphosphinato) butyric acid; C5H15N2O4P) is a commonly used polar herbicide in Malaysia and present in a variety of environmental waters at the sub-ppb level. Thus, glufosinate ammonium is analyzed in soil and water using high-performance liquid chromatography (HPLC), which is a complex yet the most powerful analysis tool. HPLC is tremendously sensitive and highly automated and HPLC instrumentation and machinery have improved over the years. However, typical problems are still encountered. HPLC users and advanced learners require help in identifying, separating and correcting typical problems. All HPLC systems consist of similar basic components. Although it is a modular system, trouble can occur in each component and change the overall performance. Resolving these problems may be expensive. This review describes the different aspects of HPLC, particularly troubleshooting, common problems and easy guidelines for maintenance.
Gynura procumbens which is locally known as 'Sambung nyawa' in Malay and 'Feng Wei Jian' in Chinese, belongs to the botanical family of Compositae. In this study, antioxidant property of G. procumbens extracts was evaluated using DPPH radical scavenging, metal chelating and β-carotene bleaching assays. To the best of our knowledge, this is the first report that evaluated the cytotoxicity of G. procumbens extracts on human colon cancer cells (HT-29, HCT 116, HCT-15, SW480, Caco-2) and human normal colon cells (CCD-18Co). The results showed that ethyl acetate extract contained the highest total phenolic content (172.68 mg of GAEs/g of extract) compared to methanol, hexane and water extracts. Methanol extract possessed better overall antioxidant activities while ethyl acetate extract demonstrated better cytotoxic activity. At 24 h treatment, ethyl acetate extract demonstrated selective cytotoxicity against HT-29 and HCT 116 cells with IC50 values of 35.7 and 42.6 μg/mL, respectively. In addition, methanol extract showed negligible level of toxicity when administered orally. All the results indicated that G. procumbens may provide benefits in prevention and treatment of cancer.
The effects of nitrogen (N) fertilization at different growth stages were investigated on durum wheat (Triticum durum L.) grain yield and yield components (with irrigated bed planting) in Diyarbakir, Turkey. N was applied at a rate of 140 kg ha–1 and distributed to one, two and three applications at various combinations with five different growth stages (i.e. sowing, seedling growth, early tillering, stem elongation and booting). This study included 13 treatments, including the control (zero nitrogen). The N application timings (NAT) of the 50% sowing + 50% early tillering and 66% sowing + 33% early tillering treatments were most suitable for durum wheat. The results showed that NAT had significant effect on flowering time, SPAD readings of the early milky ripe stage, plant density, thousand kernel weights, grain filling duration, grain filling rate, grain N content, grain yield, harvest index and grain N yield. In summary, the highest values of parameters studied were obtained from the 50% sowing + 50% first tillering and 66% sowing + 33% early tillering treatments. N fertilization application rate and time of durum wheat genotypes should consist of applying 50-60% of the total N fertilizer at sowing and 40–50% at the early tillering stage under irrigated conditions and with bed planting.
As a natural anti-oxidant source, Tualang honey, produced by wild bees nesting on the Tualang tree (Koompassia excelsa) is expected to have positive influence on health, including memory. This study investigated the effect of Tualang honey on the cell count of memory formation related hippocampal pyramidal neuron and on spatial memory performance (SMP) of rats using the radial arm maze (RAM). Sprague Dawley male rats (n=24), 7-8 weeks old were divided into two groups; experimental group group force-fed 1 mL/100 g body weight with 70% honey (HG); and the control group with 0.9% saline (CG) for 12 weeks. Nissl staining technique (with cresyl violet) was employed for neurohistological analysis of the hippocampal tissue. Six randomly selected rats from each group were used for the neuronal soma counting of pyramidal cell layer CA1, CA3a and CA3c regions. Two-way ANOVA analysis showed positively significant differences between treatment and control groups for SMP comparison of working memory and reference memory components, as well as the number of pyramidal neurons. Hence, this positive effects of Tualang honey, as demonstrated behaviorally and neurohistologically, supported report that Tualang honey could improve memory and deter hippocampal morphological impairments; possibly due to its high anti-oxidant properties.
MeSH terms: Analysis of Variance; Animals; Bees; Body Weight; Carisoprodol; Cell Count; Honey; Male; Memory, Short-Term; Staining and Labeling; Trees; Oxidants; Rats, Sprague-Dawley; Pyramidal Cells; Control Groups; Benzoxazines; Rats; CA1 Region, Hippocampal; Spatial Memory
Nicotine has been identified as one of the causal factor for oxidative stress, hypertension and hyperlipidemia. Roselle has been widely studied for its potential as an antioxidant, antihyperlipidemic and antihypertensive. However, no studies have been done to investigate if roselle could diminish the oxidative stress caused by nicotine which could further lead to cardiac damages. Thus, this study was aimed to investigate the effect of roselle extract (HSE) on blood pressure, serum lipid profile, oxidative stress marker levels and histological changes to the heart in nicotine-treated rats. A total of 21 Sprague-Dawley rats were randomly divided into 3 groups (n=7 per group): Control group received normal saline (0.5 mL/day, i.p); nicotine group received 0.6 mg/kg/BW nicotine (i.p); and treated group received 100 mg/kg/b.w HSE through oral force feeding followed with 0.6 mg/kg/b.w nicotine (i.p) for 21 consecutive days. The results showed that HSE significantly (p>0.05) reduced the heart rate but no effect to the blood pressure. For lipid profile study, HSE increased the high-density lipoprotein concentration significantly (p<0.05) in rats given with nicotine, without any significant changes in total cholesterol, triglyceride and low-density lipoprotein (LDL) concentration. Besides, HSE treatment was also found to reverse malondialdehyde (MDA) level, superoxide dimustase (SOD) enzyme activity and protein concentration significantly (p<0.05) in nicotine-treated rats. In summary, these results indicated that HSE is an effective antioxidant against oxidative damage in heart caused by nicotine, but not as antihyperlipidemic and antihypertensive agent in this rat model.
Angiogenesis has an important role in the invasion, metastasis and growth of tumors. Increased microvessel density (MVD) has been described in oral squamous cell carcinoma (OSCC) compared to oral dysplasia and normal oral tissue. A morphometric study was designed to evaluate the MVD and to evaluate the presence of any association between MVD and keratin pearl in the three histopathological grades of OSCC (as defined in Bryne’s grading system). Forty-five samples of OSCC were graded into well differentiated (WDSCC), moderately differentiated (MDSCC) and poorly-differentiated (PDSCC) oral squamous cell carcinoma. Morphometric analysis showed that MVD was significantly lower in WDSCC compared to MDSCC (p<0.001) and PDSCC (p<0.001). The density in MDSCC was significant lower than PDSCC. The keratin pearl count was significantly higher in WDSCC compared to MDSCC (p<0.001) and PDSCC (p<0.001). Between MDSCC and PDSCC, the keratin pearl count was significantly higher for MDSCC (p=0.001). Pearson correlation test showed a significant negative correlation between keratin pearl and MVD (r=-0.805, p<0.001). The findings suggested that vascularity in OSCC is associated with its cellular differentiation and also associated with keratin pearl formation.
The uniaxial compressive strength (UCS) is one of the most common mechanical parameters required in geotechnical engineering to characterize the compressive strength of rock material. Measurements of UCS are expensive, time consuming, destructive and thus, not favorable in the presence of limited samples. Therefore, a simple yet practical application is needed for the estimation of UCS. This research presents two correlations to predict UCS values for granite and schist by using ultrasonic velocity travel time (tp) from ultrasonic tests. The validity of the practical approach presented in this research is confirmed based on the strong correlations developed from the experimental tests conducted. For the entire data set, the correlation between UCS and ultrasonic velocity travel time was expressed as UCS = 217.2 e-0.016(tp) for granite and UCS = 1110.6 e-0.037(tp) for schist and the coefficient of determination (R2) value for both granite and schist is 0.93. These correlations may be useful for applications related to geotechnical engineering designs.
Effects of NaCl salinity and cadmium on the anti-oxidative activity of enzymes like superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and lipid peroxidation contents; malondialdehyde (MDA) were studied in two maize hybrids of different salt tolerance characteristics. An increase in the amount of lipid peroxidation indicated the oxidative stress induced by NaCl and Cd. The results also depicted that NaCl stress caused an increase in the activities of POD, SOD, CAT, APX and GR while cadmium stress increased the activities of POD, SOD and APX but showed no significant effect on CAT and GR in both the studied hybrids. The combined effect of salinity and cadmium on these parameters was higher than that of sole effect of either NaCl or Cd. It was also found that maize hybrid 26204 had better tolerance against both stresses with strong antioxidant system as compared to that of maize hybrid 8441. A comparison of the antioxidants and lipid peroxidation in two maize hybrids having varying level of NaCl and Cd stress tolerance corroborated the importance of reactive oxygen species (ROS) in defense against abiotic stresses.
The present study investigates heavy metal uptake and protein expression by different vegetables collected from various districts of Khyber Pakhtunkhawa province of Pakistan. Statistical analysis of the data showed that maximum concentration of Cd, Cr, Ni, Zn were found in radish and spinach, respectively, collected from Peshawar. Maximum Pb and Mg accumulation were found in cauliflower and pea at Swat followed by coriander at Haripur and minimum Pb uptake was noticed in radish taken from Nowshehra. Highest Cu uptake was detected in spinach at Nowshehra. Data regarding Cd, Cr, Pb, Cu, Ni, Mg and Zn concentration in water samples gathered from different sites of KPK indicated that maximum concentration of Cd was observed in Swat. Maximum Cr and Cu concentration were measured in water samples from Peshawar while maximum concentration of Pb and Ni were detected in water samples from Haripur. In case of soil samples, maximum Cd, Cr, Mg and Zn uptake was observed in soil sample at Nowshehra. Maximum Pb and Ni concentration was found in soil samples collected from Peshawar. Cu concentration was observed to be the highest in soil at Swat. Protein profile of different vegetables i.e. cauliflower, radish, carrot, turnip, pea, spinach, coriander and garlic sampled across five different sites showed that uptake of Cd, Cr, Pb, Cu, Ni, Mg and Zn by these vegetables caused the expression of numerous polypeptides.
Determining the water quality of Bakun Reservoir 13 months after it operates at full supply level is crucial for better understanding of changes in the physicochemical parameters, which may enable the prediction of its effects on the survival of aquatic life in the reservoir. This study determined 13 physicochemical parameters at six stations within the reservoir at fixed depths. The results showed that the minimum 5 mg/L of dissolved oxygen (DO) required for sensitive aquatic organisms was recorded at 6 m depth. However, DO was not detectable at depths exceeding 7 m. The water was acidic at depths of more than 10 m. Turbidity and total suspended solids increased corresponding with depth. Inorganic nitrogen were predominantly in the form of ammonia-nitrogen, creating an unhealthy environment for aquatic life. Concentration of Chl-a was significantly higher at the subsurface water than 30 m depth in four out of six stations. The present study shows changes in water quality as compared to the pre-impounded period and 15 months after the filling phase, in particular, stratification of dissolved oxygen, thermocline conditions and alkalinity. The changes varied according to the distance from the dam and may have been influenced by existing land developments within the area such as the construction of the Murum Hydroelectric Dam, oil palm plantations and timber concessionares. Though the water quality might have deteriorated, further study is needed to determine if this condition will prolong.
The application of microbial techniques in aquaculture has been playing a vital role to increase the production yield by improving the nutritional values of the targeted fish. Phototrophic purple bacteria as single cell protein (SCP) appears to be a promising substitution for protein rich supplement for aquaculture feeds making them a promising growth enhancer in aquaculture industry. Two species of phototrophic purple bacteria, Marichromatium sp. and Rhodopseudomonas sp. were used in the commercial diet to compare the growth, survival rate and feed utilizationon for Tor tambroides juvenile. Purple bacteria were isolated from mangrove sediment and fish tank and mass cultured using 112 synthetic media under anaerobic light condition. Bacterial cells were included in the diets by mixing the fresh biomass with the crushed commercial pellet, re-pelleted and air-dried. The experimental diets were fed to the fingerlings twice per day for 10 weeks to satiation level. The results showed that there were trends of increased growth, better survival rate and improved feed conversion ratio when fed with diet 1 (Marichromatium sp.) compared with other diets. There was significant difference (p<0.05) between the sampling days. The specific growth rate and weight gain of the fish fed with diet 1 were 0.49 % and 4.92 g, respectively, compared to 0.42% and 4.11 g from the control. This study suggested that purple bacteria could be used in feed formulation as a supplement to promote growth and survival of freshwater fishes in Malaysia.
In order to explore the response of the soil microbial community to 1,2-dichlorobenzene exposure in Wetland soil, a short-term (7 weeks) mesocosm study was conducted at four 1,2-dichlorobenzene concentrations of (100, 400 and 800) μg g -1. Dry soil, sterile and unsterile controls were also compared. The results obtained showed a significant effect of 1,2-dichlorobenzene on the development of bacterial populations in soils contaminated with different concentrations of 1,2-dichlorobenzene at the early time after application. In general, however, the number of populations of the same soil sample treated with the same concentration of 1,2-dichlorobenzene differed significantly with the increasing incubation time within the early 5 weeks. The scale of differences in banding patterns-showed that the microbial community structures of 1,2-dichlorobenzene-treated and non-1,2-dichlorobenzene-treated soils were not significantly different after 7 weeks of incubation. DNA in application-responsive bands from the 1,2-dichlorobenzene treatments was recovered and amplified using the universal primers. PCR products were recovered and cloned into pGEM-T Easy (Promega) and two clones were obtained. The two clones were sequenced using the automated Model 3730 DNA sequencing system. The two cloned sequences had very high similarities to an uncultured bacterium reported previously in the database of NCBI.
In this paper we have studied the acute toxicity effect of Hg on hybrid tilapia (Oreochromis niloticus). For this, the tissues of tilapia have been digested by means of acids in microwave oven and was analyzed by flameless atomic absorption spectrophotometer (FAAS). We have identified that the levels of Hg varied significantly in different tissues and the metal concentration was in the following order: liver > gills > muscles; of which the maximum level recorded for Hg was 0.799 mg/kg. We have also observed the alterations towards histopathological aspects in the gills and liver of treated fishes were studied using light and electron microscopy, subjected to the exposure of Hg for 24 h and furthermore we have also noticed the extent of the increased alterations during the 96 h of exposure to median lethal concentration LC50 (0.3 mg/L) a severe disorganization of epithelial cells and modifications of the structure of the secondary lamellae. Moreover the severity has also found to increase to sub-lethal concentration (0.03 mgHg/L) in 21 days of exposure; Liver was slightly affected by the contamination of Hg. Ultimately, histopathology is considered as a sensitive technique of bioaccumulation and for the observing the potential damage from Hg exposure.