195 research outputs found

    Design And Development Of Microcontroller Based Localised Air Heater

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    Although Malaysia is an equatorial country that has a tropical climate, it still has several places that has relative low ambient temperature due to the high altitude. For Cameron Highlands, the air temperature is ranged from 14.6°C to 23.3°C along the year. Humans may feel uncomfortable or unwell since the thermal comfort zone of human body ranges from 20°C to 27°C. Hence, an air heating system needs to be developed in order to solve this problem. This paper discussed the development of an air heating system that can heat up the room automatically when the temperature drops to certain value. This system is designed for a low cost but high performance. The microcontroller is used to provide control mechanism when the sensors detected a temperature drop. Fans and heating elements provide the air flow and heat

    Electrode Wear Rate On Electrical Discharge Machining of Titanium Alloys (Ti-6Al-4V) At Different Peak Current and Pulse Duration by Using Modified RBD Palm Oil as Dielectric Fluids

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    Electrical Discharge Machining (EDM) is a machining process in terms of thermoelectric that removes metal by discharging a discrete sparks series of the metal and workpiece. The cutting tool in EDM has used an electric spark to cut the workpiece of sample and produce the finished part to the demanded shape. Vegetable oil as the dielectric fluid is one way to ensure EDM's long-term viability because it is environmentally friendly and biodegradable. The main objective of this preliminary study is to compare the uses of modified bio-degradable and conventional dielectric fluid performance for a titanium alloy (Ti-6Al-4V) with a copper (Cu) electrode using a sustainable EDM process in terms of electrode wear rate (EWR). To achieve a concentration of viscosity rate as kerosene fluids, RBD palm oil has been transesterified. The effect of EWR of kerosene and modified RBD palm oil as dielectric fluids was investigated in this paper for response variables of pulse duration (ton) of 50, 100, and 150µs, and peak current (Ip) of 6, 9, and 12A. The morphology of the copper electrode, as well as the migration of workpiece material elements to the tool electrode, were studied by using scanning electron microscopy (SEM). The lowest EWR was recorded at Ip=6A with ton=150µs, which is 0.0416mm3/min and 0.0432mm3/min, and the highest EWR was recorded at Ip=12A with ton=50µs, which is 0.1725mm3/min and 0.2324mm3/min, for modified RBD palm oil compared to kerosene, respectively. The EWR rises as the peak current rises, but it decreases as the pulse duration increases. The uses of modified RBD palm oil shows slightly different results compared to kerosene

    Electrode Wear Rate On Electrical Discharge Machining of Titanium Alloys (Ti-6Al-4V) At Different Peak Current and Pulse Duration by Using Modified RBD Palm Oil as Dielectric Fluids

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    Electrical Discharge Machining (EDM) is a machining process in terms of thermoelectric that removes metal by discharging a discrete sparks series of the metal and workpiece. The cutting tool in EDM has used an electric spark to cut the workpiece of sample and produce the finished part to the demanded shape. Vegetable oil as the dielectric fluid is one way to ensure EDM's long-term viability because it is environmentally friendly and biodegradable. The main objective of this preliminary study is to compare the uses of modified bio-degradable and conventional dielectric fluid performance for a titanium alloy (Ti-6Al-4V) with a copper (Cu) electrode using a sustainable EDM process in terms of electrode wear rate (EWR). To achieve a concentration of viscosity rate as kerosene fluids, RBD palm oil has been transesterified. The effect of EWR of kerosene and modified RBD palm oil as dielectric fluids was investigated in this paper for response variables of pulse duration (ton) of 50, 100, and 150µs, and peak current (Ip) of 6, 9, and 12A. The morphology of the copper electrode, as well as the migration of workpiece material elements to the tool electrode, were studied by using scanning electron microscopy (SEM). The lowest EWR was recorded at Ip=6A with ton=150µs, which is 0.0416mm3/min and 0.0432mm3/min, and the highest EWR was recorded at Ip=12A with ton=50µs, which is 0.1725mm3/min and 0.2324mm3/min, for modified RBD palm oil compared to kerosene, respectively. The EWR rises as the peak current rises, but it decreases as the pulse duration increases. The uses of modified RBD palm oil shows slightly different results compared to kerosene

    The Machinability Performance of RBD Palm Oil Dielectric Fluid on Electrical Discharge Machining (EDM) of AISI D2 Steel

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    Electrical discharge machining (EDM) is a high-precision manufacturing process that may be implemented to any electrically conductive material, notwithstanding its of mechanical residences. It’s far a non-contact process using thermal energy that is used in a wide range of applications, especially for difficult-to-cut materials with complicated shapes and geometries. The dielectric is critical in this process as it focuses the plasma channel above the processing and also serves as a debris carrier. The long-term use of dielectric used in EDM process pollutes to the atmosphere and is harmful to the operator's health. This study compares the efficiency of refined, bleached, and deodorized (RBD) palm oil (cooking oil) with traditional hydrocarbon dielectric, kerosene using copper electrode in the finishing process of AISI D2 steel. Low peak current, Ip 1A to 5A and pulse duration, ton up to 150μs were chosen as the main parameters. The effects of material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra) were evaluated. The result shows that RBD palm oil has higher MRR which is 33.4821mm3/min while kerosene is 22.4888mm3/min, both at Ip=5A and ton=150µs. The improvement when RBD palm oil is used as dielectric is 48.88% compared to kerosene. With the increase in peak current, the EWR increases but it is inversely proportional to the pulse duration. The lowest EWR is obtained at the same IP=1A and ton=150µs for both RBD palm oil and kerosene which is 0.0010mm3/min and 0.0002mm3/min respectively. The minimum value of Ra for RBD palm oil is 2.15µm at IP=1A and ton=150µs, while for kerosene it is 2.11µm at IP=1A and ton=150µs. In terms of finishing process efficiency, RBD palm oil, a biodegradable oil-based dielectric fluid, has shown significant potential in EDM processing of AISI D2 steel

    Human gnathostomiasis: a neglected food-borne zoonosis

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    Background: Human gnathostomiasis is a food-borne zoonosis. Its etiological agents are the third-stage larvae of Gnathostoma spp. Human gnathostomiasis is often reported in developing countries, but it is also an emerging disease in developed countries in non-endemic areas. The recent surge in cases of human gnathostomiasis is mainly due to the increasing consumption of raw freshwater fish, amphibians, and reptiles. Methods: This article reviews the literature on Gnathostoma spp. and the disease that these parasites cause in humans. We review the literature on the life cycle and pathogenesis of these parasites, the clinical features, epidemiology, diagnosis, treatment, control, and new molecular findings on human gnathostomiasis, and social-ecological factors related to the transmission of this disease. Conclusions: The information presented provides an impetus for studying the parasite biology and host immunity. It is urgently needed to develop a quick and sensitive diagnosis and to develop an effective regimen for the management and control of human gnathostomiasis.[Figure not available: see fulltext.]

    Ribosomal oxygenases are structurally conserved from prokaryotes to humans

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    2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases

    Morphine Postconditioning Attenuates ICAM-1 Expression on Endothelial Cells

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    The purpose of this study is to determine 1) whether morphine postconditiong (MPostC) can attenuate the intercellular adhesion molecules-1 (ICAM-1) expression after reoxygenation injury and 2) the subtype(s) of the opioid receptors (ORs) that are involved with MPostC. Human umbilical vein endothelial cells (HUVECs) were subjected to 6 hr anoxia followed by 12 hr reoxygenation. Three morphine concentrations (0.3, 3, 30 µM) were used to evaluate the protective effect of MPostC. We also investigated blockading the OR subtypes' effects on MPostC by using three antagonists (a µ-OR antagonist naloxone, a κ-OR antagonist nor-binaltorphimine, and a δ-OR antagonist naltrindole) and the inhibitor of protein kinase C (PKC) chelerythrine. As results, the ICAM-1 expression was significantly reduced in the MPostC (3, 30 µM) groups compared to the control group at 1, 6, 9, and 12 hours reoxygenation time. As a consequence, neutrophil adhesion was also decreased after MPostC. These effects were abolished by coadministering chelerythrine, nor-binaltorphimine or naltrindole, but not with naloxone. In conclusion, it is assumed that MPostC could attenuate the expression of ICAM-1 on endothelial cells during reoxygenation via the κ and δ-OR (opioid receptor)-specific pathway, and this also involves a PKC-dependent pathway

    Immune-Mobilizing Monoclonal T Cell Receptors Mediate Specific and Rapid Elimination of Hepatitis B-Infected Cells

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    Background and Aims: Therapies for chronic hepatitis B virus (HBV) infection are urgently needed because of viral integration, persistence of viral antigen expression, inadequate HBV‐specific immune responses, and treatment regimens that require lifelong adherence to suppress the virus. Immune mobilizing monoclonal T Cell receptors against virus (ImmTAV) molecules represent a therapeutic strategy combining an affinity‐enhanced T Cell receptor with an anti‐CD3 T Cell‐activating moiety. This bispecific fusion protein redirects T cells to specifically lyse infected cells expressing the target virus‐derived peptides presented by human leukocyte antigen (HLA). Approach and Results: ImmTAV molecules specific for HLA‐A*02:01‐restricted epitopes from HBV envelope, polymerase, and core antigens were engineered. The ability of ImmTAV‐Env to activate and redirect polyclonal T cells toward cells containing integrated HBV and cells infected with HBV was assessed using cytokine secretion assays and imaging‐based killing assays. Elimination of infected cells was further quantified using a modified fluorescent hybridization of viral RNA assay. Here, we demonstrate that picomolar concentrations of ImmTAV‐Env can redirect T cells from healthy and HBV‐infected donors toward hepatocellular carcinoma (HCC) cells containing integrated HBV DNA resulting in cytokine release, which could be suppressed by the addition of a corticosteroid in vitro. Importantly, ImmTAV‐Env redirection of T cells induced cytolysis of antigen‐positive HCC cells and cells infected with HBV in vitro, causing a reduction of hepatitis B e antigen and specific loss of cells expressing viral RNA. Conclusions: The ImmTAV platform has the potential to enable the elimination of infected cells by redirecting endogenous non‐HBV‐specific T cells, bypassing exhausted HBV‐specific T cells. This represents a promising therapeutic option in the treatment of chronic hepatitis B, with our lead candidate now entering trials
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