19672 research outputs found
Sort by
Phenytoin toxicity presenting with acute visual loss and acute delirium, a case report
No full textPhenytoin is a widely prescribed antiepileptic agent for both focal and generalized seizure. We report a case of a 20-year-old man with focal epilepsy presented with acute bilateral visual loss, and delirium. His random phenytoin serum concentration on admission was 43.6 mg/L, well above the recommended therapeutic range of 10-20 mg/L. Extensive investigations have ruled out other vascular or demyelinating causes. His visual symptoms completely resolved after discontinuing phenytoin for 84 hours. This case shows that acute phenytoin toxicity can result in reversible visual failure
Concentric Circles and Spiral Configurations for Large Correlator Arrays in Radio Astronomy
No full textAperture synthesis arrays are commonly used in radio astronomy to take images of radio point sources, with the planned Square Kilometre Array (SKA) being the most common example. One approach to enhancing the quality of the images is to optimize an antenna array configuration in a possible SKA implementation. An ideal arrangement must ensure optimal configurations to capture a clear image by either decreasing the sidelobe level (SLL) in the l-m domain or increasing the sampled data in the spatial-frequency domain. In this paper a novel configuration is considered to optimize the array by considering all possible observation situations through the positions of the antenna array elements via a mathematical model that we call geometrical method (GM). To demonstrate its efficiency, the technique is applied to developing an optimal configuration for the elements of the Giant Metrewave Radio Telescope (GMRT). The effect of these changes, particularly in the forms of circular and spiral arrangements, is discussed. It is found that a spiral configuration results in fewer overlapping samples than the number of antennas placed along three arms of the GMRT with fewer than 11% and 27% overlapping samples in the snapshot and 6 hr tracking observations, respectively. Finally, the spiral configuration reduces the first SLL from -13.01 dB, using the arms of the current GMRT configuration, to -15.64 dB
Microalgae cultivation in palm oil mill effluent (POME) for lipid production and pollutants removal
No full textMicroalgae cultivation in wastewaters has been identified as the solution for economical microalgae cultivation. This study investigated the feasibility of using POME for Chlorella sp. cultivation to yield biomass and lipids, as it generates massively in Malaysia which ranked world palm oil exporter. The optimal POME concentration and pretreatment strategy were applied to promote biomass and lipid productivities. Chlorella sorokiniana CY-1 attained maximal of 11.21% of lipid content with 2.12 g L−1 of biomass concentration when cultivation in acid-heat pretreated 30% (v/v) POME. This provides relatively higher yield than those reported values on POME. Pretreatment was found effective to enhance biomass productions, as it converts lignin in POME into reducing sugars to serve as the supplement. The pollutants removal efficiencies were 62.07% for TN, 47.09% for COD, and 30.77% for TP. This contributes towards greater feasibility in microalgae cultivation for biofuel productions and as well towards environmental sustainability
Synthesis and electrochemical characterization of amorphous manganese-nickel oxide as supercapacitor electrode material
No full textAn amorphous composite film consisted of manganese and nickel oxide was synthesized using simple chronopotentiometry method and tested as electrode material for supercapacitor. The composite film was examined using X-ray diffraction, transmission electron microscopy, and electrochemical characterizations. The electrochemical characterization was performed using cyclic voltammetry, galvanostatic charge-discharge, and frequency response analyzer by a three-electrode configuration. The prepared composite electrode remained amorphous until 400 °C. The composite film deposited at 13 min and annealed at 300 °C was found to perform the best. It exhibited a good specific capacitance of 670 F g−1 over a potential window of 1 V in 1 M Na2SO4. Annealing temperature higher than 300 °C brought about a rapid decrease in specific capacitance. The composite electrode remained 61% of initial specific capacitance after 1000 cycles
CFD models comparative study on nanofluids subcooled flow boiling in a vertical pipe
No full textThe effects of subcooled flow boiling of nanofluids (Al2O3/water and Cu/water) through a vertical heated pipe are investigated numerically considering a number real flow factors such as uneven particle distributions and particle deposition on the wall surface. The results from the Eulerian–Eulerian two-phase model (liquid/nanofluid–gas) and those of the Eulerian–Lagrangian three-phase model (liquid–gas particles) are compared in detail. For the heat transfer coefficient prediction, the latter model gives about 6% error, whereas the Eulerian–Eulerian model gives about 12% error when it is compared with Chen’s correlation. The uneven distribution of nanoparticles concentrations, i.e., lower near the tube wall and higher at the pipe center, is well predicted by the Eulerian–Lagrangian model. On top that, for the first time, the changes on heating surface wettability induced by nanoparticles deposition is included via user define functions
Effect of utilizing unground and ground normal and black rice husk ash on the mechanical and durability properties of high-strength concrete
No full textThe aim of the present study is to investigate the effects of utilizing different processings of normal rice husk ash (RHA) and black rice husk ash (BRHA) on the mechanical and durability properties of high-strength concrete (HSC). Mechanical and durability properties of HSC were evaluated on concrete mixes containing unground BRHA and RHA and ground BRHA and RHA, their average particles sizes being 165, 85, 67 and 24 µm, respectively. The replacement of ordinary Portland cement with the ashes was adopted at 20%. The results showed that incorporating any form of RHA and BRHA in HSC reduced the slump value. The surface areas of RHA and BRHA, not their carbon content, determined the dosage of superplasticizer needed to achieve a targeted slump value. Concrete with unground and ground RHA incorporated exhibited 30% higher compressive strength while unground BRHA produced 30% lower compressive strength than that of the control concrete. Incorporating unground and ground RHA showed a synergy between filler and pozzolanic effect and had insignificant difference in mechanical and durability properties of the concretes. Meanwhile, incorporating ground BRHA showed a dominant filler effect in the concrete. Overall, the improvement of splitting tensile strength and modulus of elasticity of both RHA and GBRHA concrete showed a similar trend to that of the compressive strength of RHA concrete. The durability of concretes with unground and ground RHA and ground BRHA incorporated showed better performance than that of the control concrete. The material with 20% ground BRHA as partial cement replacement in HSC of Grade 50 could be used without any reduction in the mechanical and durability properties. Use of unground BRHA is not recommended because it did not improve these properties
Ethanolic extract of Brucea javanica inhibit proliferation of HCT-116 colon cancer cells via caspase activation
No full textBrucea javanica (L.) Merr. is a well-known plant in Chinese System of Medicine. Its fruits and seeds have been reported to possess curative properties against various ailments. The chemical constituents and biological activity of this plant have been an interesting area in plant and chemistry medicine. The aim of this study is to evaluate the antiproliferative effects of the B. javanica extract against a colon cancer cell line and identification of the chemical components derived from the extract. An ethanolic extract from B. javanica fruits was prepared by cold maceration method, subjected to LC-MS profiling to elucidate the composition abbreviated as BJEE. The extract was screened for the cytotoxicity effects on HCT-116 colon cancer cells via MTT and LDH methods. Additionally, AO/PI staining verified apoptosis features in HCT-116 cells through microscopic analysis. ROS, caspase activity, and gene expression has been performed to identify its possible mechanism of actions which contribute to apoptosis. Output data from this study showed BJEE inhibited the cell proliferation of HCT-116 colon cancer cells at IC50 value of 8.9 ± 1.32 (μg mL-1) and significantly increased the levels of caspase-8, 9, and 3/7 in treated cells in comparison to untreated. The changes in expression of caspase genes and some apoptosis genes like Bax and Bcl-2 were confirmed using RT-PCR. Phytochemical analysis by LC-MS identified six major active compounds (bruceine D, isobrucein A, quassimarin, C16 sphinganine, phytosphingosine, and enigmol) in BJEE that may play a key role in cell apoptosis. The current study showed BJEE could be a promising agent for colorectal cancer therapy by significant increase in caspase activity level, and up-regulation of the specific apoptotic genes
Application of graphene oxide based Microfiber-Knot resonator for relative humidity sensing
No full textA relative humidity (RH) sensor is proposed and demonstrated using a micro-knot resonator (MKR) enhanced with a layer graphene oxide (GO) coating. The MKR is fabricated by means of tapering a standard fiber, with the GO coating added by the drop-cast method. The proposed sensor is tested for an RH range of between 0% and 80% at 20% intervals, and the configurations with and without the GO coating achieve sensitivities of 0.0104 nm/% and 0.0095 nm/%, respectively. The MKR configuration without the GO coating has a linear response correlation coefficient of 0.9098 and a resolution of 0.1%, while the configuration with the GO coating has a linear response correlation coefficient of 0.9548 and a resolution of 0.096% which is better. The proposed sensor has multiple applications, especially in the area of climate and atmospheric measurement and monitoring
Robust strain sensor based on multimode interference in single-mode–multimode–single-mode fiber structure
No full textSingle-mode–multimode–single-mode (SMS) structure is demonstrated as a strain sensor. The device is fabricated by splicing a section of multimode optical fiber (MMF) in between single-mode fibers (SMFs). The modal interference inside the structure produces a strong resonant transmission notch, which is sensitive to external perturbation. It was found that the position of the notch changed with strain at sensitivity of 1.3 nm/N. The device introduced here is simple to fabricate, robust and suitable for high temperature operation; hence, it is adequate for diverse sensing applications
Determinants of scholar's participation of OAI: Developing a conceptual framework
No full textThis paper describes the framework used in a study to formulate the requirements for the design and implementation of a knowledge sharing for project-based education. Green Open Access Information is popular among researchers to access information in sharing their knowledge. The purpose of Green Open Access Information is to make the full text of the peer-reviewed research output of scholars/scientists and their institutions visible, accessible, harvestable, searchable and useable by any potential user to access the information from the Internet. Knowledge sharing is widely recognized that it can promote the competitive ability of scholars and it has been the focus of research for this century. Recently, there has been a growing interest in examining the factors that participation of OAI or knowledge sharing. The OAI has been conceived to support scholars sharing needs in making research projects. The study uses the Framework for knowledge sharing for the approach to investigate the initial requirements. The artifact addressed in the framework - readiness - is highlighted in this paper. Readiness in this work refers to major goal within objective or approaches that are significant to the OAI. This includes the readiness to participate the OAI, willingness to participate in making research articles available on the internet, and the success factors. Using multiple data-gathering techniques, the study identifies the readiness factors that support the plan for participation of the OAI. It outlines the vision statement, goals and objectives needed to define the make research articles available on the internet by the Scholars; the context to participate the OAI by the Knowledge Sharing Community; and the knowledge sharing expressed by the participation of OAI