192 research outputs found

    No association of BgII dimorphism of human renin gene in hypertensive subjects in Malaysia.

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    The presence of a dimorphic BglI site in the first intron of the Renin (REN) gene is an increased risk in essential hypertension. Several studies have found the association between BglI dimorphism and essential hypertension with conflicting results in various populations, which might be due to ethnic and geographical variations. The objective of this study is to determine the relationship between the BglI dimorphism of REN gene and Essential Hypertension (EHT) with or without Type 2 Diabetes Mellitus (T2DM) in Malaysian subjects. The study includes 70 EHT, 60 EHT with T2DM and 70 unrelated healthy subjects from the three ethnic groups of Malaysian Subjects. The genotype of BglI dimorphism was done by PCR-RFLP method using BglI restriction enzyme. The frequency of the BglI (+) allele was 37.86% in EHT, 40.83% in EHT with T2DM subjects and 35.71% in control subjects. The results of this study indicate that the BglI (+) allele of REN gene is not associated with essential hypertension with or without T2DM in Malaysian Subjects

    Effect of raw material variation, process variables and device stability on drying process of rambutan (Nephelium lappaceum L.) seed

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    This study was conducted to determine the influence of raw material variation, equipment process variables and device stability on the drying process of rambutan seed using oven and microwave drying equipments. The raw material variations studied were skin colour (yellow and fully red), storage period (fresh and stored) and seed mass (5 and 10 g). The important equipment process variables studied were oven temperature (40 and 60°C) and microwave power (250 and 1000 W).The output power and drying distribution in the drying chamber were studied to examine the device stability. Results indicated that the seed mass, oven temperature and microwave power influenced the drying time. The skin colour and storage period were negatively correlated with drying time due to drying time speculate to relay on time required for moisture removal that associated to initial moisture content and seed mass. It is also observed that the drying time will be shorten if the sample was located at the central of the microwave drying chamber. In contrast, the oven exhibited higher stability compared to microwave due to its ability to provide similar level of heating at each location in the drying chamber. This information will aid researchers and industrial operators to design an effective drying process using microwave and oven thus reducing cost and time

    The Phenomena of Spreading of Hydrotalcite Sol on A Porous Silica Surface Governed by Marangoni Effect

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    Wetting phenomena plays a crucial role in a wide range of technological applications. Spreading of liquids on solids involving phase change is encountered in many areas ranging from biological systems to industrial applications such as coatings, printing, painting and spraying. The fundamental study on wetting of membrane precursors namely hydrotalcite sols on a porous silica surface with different types of precursor material was successfully carried out. Relationship between the contact angle of a hydrotalcite droplet on silica surface and the Marangoni effect was also investigated. The presence of PVA in hydrotalcite sols was found to influence the rheological properties of the sols significantly, resulting in higher viscosity and ultimately leading to lower contact angle on solid surfaces. The degree of hydrotalcite's philicity on a substrate was improved by the addition of PVA solution. In this study, the spreading of a liquid droplet on a solid surface controlled by a surface tension gradient, due to Marangoni effect was found to drive better spreading of the liquid droplet. Marangoni Number, Ma was found to be proportionally related with the surface tension of the sols but inversely proportional to contact angles of the sols. Marangoni forces that decreased the contact angle, promoted spreading of hydrotalcite droplets on the selected glass substrates.Keywords: contact angle, hydrotalcite, marangoni effect, spreading, wetting evolutio

    A Note on Redesign Material Substitution and Topology Optimization in a Lightweight Robotic Gripper

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    The gripper is required because it is the portion of the robot that makes direct contact with the object being grasped. It should weigh as little as possible without compromising functionality or its performance. This study aims to reconsider the construction of a lightweight robotic gripper by modifying the gripper's materials and topology. Using the finite element (FE) method, several types of gripper materials were evaluated for static stress. On the basis of the results of the FE analysis, the optimal material candidate was chosen using the weighted objective method. Using the Fusion 360 software, the topology of the selected material was then optimized in an effort to achieve the 40% weight reduction’s objective. In addition, the suggested optimized geometry is then fine-tuned so that it can be manufactured as efficiently as possible. The final step in the validation of the robotic gripper's design was stress static analysis. The revised gripper design has a mass of 0.08 kg, a reduction of 94% from the original mass, and a safety factor of 3.67%, which satisfies the desired level of performance for the robotic gripper. Utilizing different materials and optimizing the gripper's topology can significantly reduce the overall mass of a robotic gripper. &nbsp

    Association of Insertion/Deletion Polymorphism of Alpha-Adrenoceptor Gene in Essential Hypertension with or without Type 2 Diabetes Mellitus in Malaysian Subjects

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    An insertion/deletion (I/D) polymorphism of Alpha2B-Adrenoceptor (ADRA2B) gene located on chromosome 2 has been studied extensively in related to cardiovascular diseases. The main aim of the present study was to examine the potential association of D allele frequency of I/D polymorphism of ADRA2B gene in Malaysian essential hypertensive subjects with or without type 2 diabetes mellitus (T2DM). This study includes 70 hypertensive subjects without T2DM, 65 hypertensive subjects with T2DM and 75 healthy volunteers as control subjects. Genotyping of I/D polymorphism was performed by conventional PCR method. There was significant difference found in age, body mass index, systolic/diastolic blood pressure and high density lipoprotein cholesterol level between the case and control subjects. DD genotypic frequency of I/D polymorphism was significantly higher in hypertensive subjects (42.84% vs. 29.33%; P­=0.029) and in hypertensive with T2DM subjects (46.15% vs. 29.33%; P=0.046) than control group. D allele frequency was higher in hypertensive group (67.41%) than control subjects (52.67%). However, no significant difference was found between the three genotypes of I/D polymorphism of ADRA2B gene and the clinical characteristics of the subjects. The result obtained in this study show D allele of ADRA2B gene was associated with essential hypertension with or without T2DM in Malaysian subjects

    Low blood lead concentrations and cognitive development of primary school children from three areas in Malaysia.

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    A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 6½ - 8½ years from urban (236), rural (80) and industrial areas (97) were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer (GFAAS). Cognitive development was measured by the ‘McCarthy Scales of Children’s Abilities Test’ (MSCA). Significant differences found in the mean cognitive scores between the urban (94.40), industrial (102.90) and suburban children (101.24) (p ≤ 0.001), with the blood lead between the urban (3.66 μg/dL), industrial (3.54 μg/dL) and suburban children (3.04 μg/dL) (p = 0.022). Significant inverse correlations between blood lead and cognitive scores found for all groups (p ≤ 0.001), urban (p ≤ 0.001) and suburban children (p < 0.001). Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders (p ≤ 0.001). The urban children’s cognitive scores were significantly influenced by blood lead levels and household income (p ≤ 0.001). However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers’ education, number of siblings, sequence in the family and the household income (p < 0.001). Blood lead below 10 μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development

    Nano Fe3O4-activated carbon composites for aqueous supercapacitors

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    In this study, a symmetric supercapacitor has been fabricated by adopting the nanostructured iron oxide (Fe3O4)-activated carbon (AC) composite as the core electrode materials. The composite electrodes were prepared via a facile mechanical mixing process and PTFE polymeric solution has been used as the electrode material binder. Structural analysis of the nanocomposite electrodes were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances of the prepared supercapacitor were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1.0 M Na2SO3 and 1.0 M Na2SO4 aqueous solutions, respectively. The experimental results showed that the highest specific capacitance of 43 F/g is achieved with a fairly low Fe3O4 nanomaterials loading (4 wt. %) in 1 M Na2SO3. It is clear that the low concentration of nanostructured Fe3O4 has improved the capacitive performance of the composite via pseudocapacitance charge storage mechanism as well as the enhancement on the specific surface areas of the electrode. However, further increasing of the Fe3O4 content in the electrode is found to distort the capacitive performance and deteriorate the specific surface area of the electrode, mainly due to the aggregation of the Fe3O4 particles within the composite. Additionally, the CV results showed that the Fe3O4/AC nanocomposite electrode in Na2SO3 electrolyte exhibits a better charge storage performance if compared with Na2SO4 solution. It is believed that Fe3O4 nanoparticles can provide favourable surface adsorption sites for sulphite (SO32-) anions which act as catalysts for subsequent redox and intercalation reactions

    Analysis of three genetic polymorphisms in Malaysian essential hypertensive and type 2 diabetic subjects

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    Genetic polymorphisms were associated with an increase in the risk of developing disease and they are integral to the development of genetic marker to identify the individuals at risk. The genotypic distribution of various genetic polymorphisms involved in essential hypertension (EHT) and type 2 diabetes mellitus (T2DM) in Malaysian subjects has not been well characterized. The main objective of this study was to determine the association of S477X polymorphism of LPL gene, A6244G polymorphism of IRS-1 gene and C825T polymorphism of GN 3 gene with EHT and T2DM in Malaysian subjects. This study includes 70 EHT, 60 T2DM, 65 EHT with T2DM and 75 control subjects. Genotyping of all the three polymorphisms was performed by PCR-RFLP method with the respective primers and restriction enzymes. The genotypic and allelic frequencies of the respective polymorphisms of the genes did not differ significantly (p&gt;0.05) with EHT and T2DM in Malaysian subjects. The results of this study suggested that, S477X genotypes of LPL gene, A6244G genotypes of IRS-1 gene and C825T genotypes of GN 3 gene was not associated with EHT and T2DM in Malaysian subjects

    Escherichia coli growth modeling using neural network

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    The assessment of water microbial quality is normally performed by verification ofEscherichia coli where the growth is in nonlinearity. NARX is computational tools that haveextensive utilization in solving nonlinear time series problems. It is well known as one of thetechnique that has the ability to predict with efficient and good performance. Using NARX, ahighly accurate model was developed to predict the growth of Escherichia coli (E. coli) basedon pH water parameter. The multiparameter portable sensor and spectrophotometer data wereused to build and train the neural network. The selection of neural network structure for pHand optical density modelling was optimized and also the training and validation wereanalyzed. The result exhibited that NARX modelling was able to predict the growth of E. colibased on pH water parameter with overall regression is 0.99956.Keywords: neural network; NARX; prediction; Escherichia coli; pH; optical density
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