19672 research outputs found
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Characterizing a Halo-Tolerant GH10 Xylanase from Roseithermus sacchariphilus Strain RA and Its CBM-Truncated Variant
No full textA halo-thermophilic bacterium, Roseithermus sacchariphilus strain RA (previously known as Rhodothermaceae bacterium RA), was isolated from a hot spring in Langkawi, Malaysia. A complete genome analysis showed that the bacterium harbors 57 glycoside hydrolases (GHs), including a multi-domain xylanase (XynRA2). The full-length XynRA2 of 813 amino acids comprises a family 4_9 carbohydrate-binding module (CBM4_9), a family 10 glycoside hydrolase catalytic domain (GH10), and a C-terminal domain (CTD) for type IX secretion system (T9SS). This study aims to describe the biochemical properties of XynRA2 and the effects of CBM truncation on this xylanase. XynRA2 and its CBM-truncated variant (XynRA2ΔCBM) was expressed, purified, and characterized. The purified XynRA2 and XynRA2ΔCBM had an identical optimum temperature at 70 °C, but different optimum pHs of 8.5 and 6.0 respectively. Furthermore, XynRA2 retained 94% and 71% of activity at 4.0 M and 5.0 M NaCl respectively, whereas XynRA2ΔCBM showed a lower activity (79% and 54%). XynRA2 exhibited a turnover rate (kcat) of 24.8 s-1, but this was reduced by 40% for XynRA2ΔCBM. Both the xylanases hydrolyzed beechwood xylan predominantly into xylobiose, and oat-spelt xylan into a mixture of xylo-oligosaccharides (XOs). Collectively, this work suggested CBM4_9 of XynRA2 has a role in enzyme performance. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Addressing education inequality in sub-Saharan Africa
No full textThis paper examines the impact of wealth inequality on education inequality in the sub-Saharan African (SSA) countries, including by decomposing inequality across gender. Specifically, it analyzes the impact of wealth concentration on the distribution of educational attainment using a sample of cross-sectional data from the USAID Demographic Health Survey on 25 countries, and deploying the education inequality Gini, generalized Lorenz curve, and Lorenz concentration curve. Educational attainment and wealth index were estimated to capture education inequality and wealth concentration. The findings confirm that social exclusion has remained chronic in SSA. Apart from Zimbabwe, SSA have not only failed to raise incidence levels of secondary and tertiary education, but also have largely been unable to reduce education inequality. Regardless of oil and gas endowments, investments going to education have remained low in these countries, while gender disparity on educational attainment burdening females has been high in Nigeria, Gambia, Ghana and Guinea. With the exception of Comoros, wealth concentration is the prime cause of education inequality in the remaining countries. The findings call for effective policies for the poor and females to raise their education levels thereby enabling them to earn incomes to break the vicious cycle of education inequality caused by wealth inequality. © 2019, © 2019 African Journal of Science, Technology, Innovation and Development
Design and development of an online robot programming and simulation framework using the Robot Operating System (ROS)
No full textIn the Fourth Industrial Revolution, robotics technology plays an increasingly important role in order to increase productivity through the use of cyber-physical systems. However, industrial robotic arms require expertise in fields such as mechanical and software engineering in order to be used. Furthermore, the modularity of robotic work cells could be improved. In this project, an online robot programming and Simulation framework is developed in the Robot Operating System (ROS). The framework includes a master and slave node that allows for teleoperation of the intended robotic arm. A graphical user interface (GUI) is provided on the master personal computer (PC) in order to receive a target coordinate point for the robotic arm end-effector from the user. The EezyBotArm Mk2 3-dimensional (3D) printed arm is used for control and testing. The kinematics study of the robotic arm is performed and based on the equations derived is used to convert the coordinate point into the corresponding joint variables. The joint variables are then transmitted from the master PC to the slave Raspberry Pi. The Raspberry Pi interfaces with an Arduino UNO board in order to control the servo motors on the robotic arm via pulse width modulation (PWM) signal
Effects of Resin Binder on Characteristics of Sintered Aluminum–Copper Nanopaste as High-Temperature Die-Attach Material
No full textThis paper aims to report an aluminum-copper (Al-Cu) die-attach system as a Pb-free alternative for electronic applications. The Al-Cu die-attach system is formulated by a mixture of Al and Cu nanoparticles and a constituent of organic compounds and sintered at 380 °C ± 10 °C without any pressure application. The effects of organic additives on physical, structural, and electrical properties are investigated to understand the die-attach quality of Al-Cu nanopaste. The formation of CuAl2 phase is discovered, which confirmed the joining of Al and Cu nanoparticles in sintered nanopaste layer. Solid-state fusion of Al and Cu can be seen in scanning electron microscope (SEM) analysis. Energy dispersive X-ray (EDX) analysis demonstrates sample of 0.25-g V006A has the lowest oxygen element at 15.36%. Sample with 0.25-g organic additives exhibits the smallest crystallite size and electrical resistivity, which were 8.15 nm and 21μΩ · cm , which is favorable for high-temperature applications. © 2011-2012 IEEE
A 2.2 to 2.9 GHz Complementary Class-C VCO With PMOS Tail-Current Source Feedback Achieving – 120 dBc/Hz Phase Noise at 1 MHz Offset
No full textThe performance of low-powered transceivers is required to meet stringent specifications for an advanced wireless radio application. It is critical for a voltage-controlled oscillator (VCO) to meet multi-standard and multiple frequency operation with low-power consumption and amplitude enhanced complementary mode of operation. This paper proposes a novel technique for wide tuning range in a complementary class-C VCO employing a capacitive-source degeneration (CSD) to meet multi-standard operation for low-power transceivers. The technique that employs two sets of symmetrical split PMOS biased current source operating in the subthreshold region achieves the desired low phase noise (PN) performance at a tuning range of 2.2-2.9 GHz with a supply headroom of 1.2 V. The control of the dc bias point reduces the conduction angle, which improves the current efficiency, power consumption, and PN. Concurrently, an auxiliary NMOS only class-B oscillator is incorporated to mitigate the start-up issue of the class-C VCO. At the center frequency of 2.45 GHz, the proposed VCO achieves a power consumption of 1.73 mW, phase noise of-120 dBc/Hz at the 1-MHz offset, and a figure-of-merit (FoM) of 185.41 dBc/Hz at 1 MHz. The total active chip area is only 0.3-mm2 excluding bond pads. The proposed VCO serves as a promising solution for low-power wireless communication systems. © 2013 IEEE
Detection of human sarcocystosis using dried blood on filter papers: An immunofluorescent antibody test
No full textSarcocystosis, a parasitic infection caused by a protozoa belonging to the genus Sarcocystis, is found worldwide in both and animals. Sarcocystis spp., require two animal hosts to complete their life cycle. The infection has gathered more global attention after recent outbreaks, especially amongst wester travellers to Malaysia. Other than sporadic cases and the current outbreaks, little information is available regarding human Sarcocystis infection in Malaysia. The present study aims to determine the prevalence of sarcocystosis among humans using an immunofluorescent antibody (IFA) test applied to dried blood on filter papers. A total of 200 blood samples were collected on filter papers from autopsy cases at two Malaysian hospitals: Sungai Buloh Hospital (peninsular Malaysia) and Queen Elizabeth Hospital (Malaysian Borneo). Antigens were prepared from bradyzoites harvested from positive goats’ muscle samples. Of the 200 samples, 32 (16%) had Sarcocystis antibodies that showed positive fluorescence reactions on filter papers. There was no significant difference (t-test, p value > 0.05) in prevalence rates between samples collected from autopsies at peninsular Malaysia and Malaysian Borneo. The results demonstrated that the filter paper technique can be used as one of the alternative serological tests in the diagnostic of human sarcocystosis. © 2019, Malaysian Society for Parasitology. All rights reserved
Accuracy evaluation of methods and techniques in Web-based question answering systems: a survey
No full textQuestion answering (QA) systems answer the queries of users efficiently in the least amount of time. A researcher has to decide which among various methods and techniques available will be used to retrieve accurate answers when developing a QA system. This step creates an overhead before making a selection.The study highlights the methods and techniques that perform well in terms of the accuracy of answers provided. Nine Web-based question answering systems were consulted, and the applied methods and techniques evaluated on the basis of the percentage of questions correctly answered and the mean reciprocal rank evaluation measures. Results were discussed using three key stages involved in a QA system: answer extraction, scoring of answers, and answer aggregation. Results show some techniques have higher accuracy of answers than others. Not all methods in QA systems can improve the accuracy of answers individually, but the methods used in combination obtain greater effect. The results can be used to select methods and techniques optimal for producing highly accurate scores without spending time on benchmarking. © 2018, Springer-Verlag London Ltd., part of Springer Nature
The effectiveness of psychological skills training program on netball shooting performance [Efektivitas program psychological skill training pada keterampilan tembakan netball]
No full textThe study was aimed to investigate the effect of Psychological Skills Training Program on netball shooting performance. The experimental method was used on three groups of an 8-week intervention: combination of diaphragmatic breathing and imagery, plus physical practice (G1); combination of DB and self-talk, plus physical practice (G2); and control group which have physical practice only (G3). A SPANOVA was conducted to assess the impact of all groups on shooting performance across the two time periods. The main effect comparing the two treatments and a control group was significant, p < .001. Post hoc Tukey test differ significantly at p < .05. However, the G2 was not significantly different from the G3. The results indicated that netballers of different skill used of PST, either G1 or G2 were found to improve the netball shooting performance. It was also showed that G1 has better netball shooting performance rather than G2 and G3. As to highlighting, that the principles and practical applications of these most basic psychological skills can be taught in easier ways and probably in a relative short period of time among youth athletes. © 2019, Universitas Negeri Yogyakarta (Yogyakarta State University). All rights reserved
Development of a Sexually Transmitted Disease Client-friendly Unit at a Primary Care Clinic in Malaysia: Lessons Learnt
No full textManagement of sexually transmitted diseases and human immunodeficiency virus is challenging due to the social stigma attached. We describe the development of a client-friendly sexually transmitted disease service in a primary care clinic in Malaysia with a special focus on key populations. Challenges and key lessons learnt from its development and implementation are discussed. © Copyright 2018 American Sexually Transmitted Diseases Association All rights reserved
Decolorization of selected azo dye by Lysinibacillus fusiformis W1B6: Biodegradation optimization, isotherm, and kinetic study biosorption mechanism
No full textThis study reports on the evaluation of biodegradation and biosorption mechanism of indigenous bacteria on azo dye decolorization. The bacterial strains were screened for their ability in decolorizing of selected toxic azo dyes in aqueous solution. Lysinibacillus fusiformis W1B6 showed the highest decolorizing of about 96% of methyl red within 2 h, with the specific growth rate of 0.273/h. The optimum decolorization under aerobic condition was achieved at pH 7.5, 30 ± 2°C, inoculum 10% (v/v), and initial dye concentration of 100 mg/L. Spectrum analysis confirmed biodegradation as the principal mechanism of decolorization, although biosorption also occurred. Extracellular and intracellular azoreductase, laccase, and lignin peroxidase plays a role in the oxidoreductive mechanism of decolorization. The absorption isotherms fitted with the Langmuir equation and the reaction kinetics of methyl red decolorization followed a pseudo first-order. © The Author(s) 2019