134 research outputs found
Teachers’ readiness and usage of online teaching practices in the Kingdom of Saudi Arabia: An empirical investigation
The substantial disruption caused by the COVID-19 epidemic to the world's education system is only one of the many setbacks the world has recently experienced. The transition of the students from their offline learning mode to a fully digital approach was not easy from the beginning for them. The online teaching readiness heavily relied on their competencies and skills to adapt the pedagogy, training, technical skills, a proper mindset and new roles. This research endeavors to evaluate the readiness of the teachers belonging to higher education institutions (HEIs) to handle online education based on the online teaching readiness model. A systematic questionnaire with 30 statements was used by the researcher to collect and analyse data from 296 HEI lecturers in Saudi Arabia. Smart PLS3 was used to attain reliability, convergent, discriminate validity and model fitness. These programs will help equip the teachers with the necessary technical skills, pedagogy, competency and readiness to comprehend the requisite techniques of online teaching and the vital strategies for keeping their students engaged. Technical proficiency, pedagogy, competency and teaching readiness show a direct relationship with online education. On the other hand, attitude and training do not show any relationship with online education
DESIGN AND MIXING PERFORMANCE OF PASSIVE MICROMIXERS: A CRITICAL REVIEW
This study extracts and reports notable findings on passive micromixers by conducting an exhaustive review of designs, their features, and mixing performance. The study has covered the relevant articles on passive micromixers published from 2010 to 2020. The analysis of filtered and selected articles sums up passive micromixers into four categories: designed inlets, designed mixing-channel, lamination-based, and flow obstacles-based. The prominent mixing channel categories identified in the study are split-and-recombine (SAR), convergent-divergent (C-D), and mixed (SAR, C-D, and others). Moreover, differences in mixing channel designs, number of inlets, and evaluation methods have been used in comparing the mixing performance of passive micromixers. The SAR and the obstacles-based micromixers were found to outperform the others. The designs covered in the present review show significant improvements in the mixing index. However, these studies were conducted in an isolated environment, and most of the time, their fabrication and device integration issues were ignored. The assortment and critical analysis of micromixers based on their design features and flow parameters will be helpful to researchers interested in designing new passive micromixers for microfluidic applications
Performance enhancement of Wells turbine: Combined radiused edge blade tip, static extended trailing edge, and variable thickness modifications
The Wells turbine is used in conjunction with an oscillating water column to harvest wave energy. It is a self-rectifying axial flow reaction turbine which consists of symmetrical blades aligned normal to the incoming flow. A narrow operating range due to flow separation restricts the power extracting capability of the turbine at a higher flow rate. To improve its performance, a turbine blade with combined design modifications such as radiused edge blade (RED) tip, static extended trailing edge (SETE) and variable thickness blade (VTB) was investigated through CFD analysis. Three-dimensional time independent Reynolds-averaged Navier-Stokes equations were solved in a commercial solver to obtain the turbine performance, which was given by non-dimensional torque, pressure drop and efficiency. The combined REB tip, SETE and VTB modifications enhanced relative average turbine power output by 97% and the relative operating range by 22%. However, the average efficiency is decreased by 7.7%, because of the increased pressure drop
Metabolic Profiling of the Protozoan Parasite Entamoeba invadens Revealed Activation of Unpredicted Pathway during Encystation
Encystation, which is cellular differentiation from the motile, proliferative, labile trophozoite form to the dormant, resistant cyst form, is a crucial process found in parasitic and free-living protozoa such as Entamoeba, Giardia, Acanthamoeba, and Balamuthia. Since encystation is an essential process to deal with the adverse external environmental changes during the life cycle, and often integral to the transmission of the diseases, biochemical understanding of the process potentially provides useful measures against the infections caused by this group of protozoa. In this study, we investigated metabolic and transcriptomic changes that occur during encystation in Entamoeba invadens, the reptilian sibling of mammal-infecting E. histolytica, using capillary electrophoresis-tandem mass spectrometry-based metabolite profiling and DNA microarray-based expression profiling. As the encystation progressed, the levels of majority of metabolites involved in glycolysis and nucleotides drastically decreased, indicating energy generation is ceased. Furthermore, the flux of glycolysis was redirected toward chitin wall biosynthesis. We found remarkable temporal increases in biogenic amines such as isoamylamine, isobutylamine, and cadaverine, during the early period of encystation, when the trophozoites form large multicellular aggregates (precyst). We also found remarkable induction of γ-aminobutyric acid (GABA) during encystation. This study has unveiled for the first time the dynamics of the transcriptional and metabolic regulatory networks during encystation, and should help in better understanding of the process in pathogenic eukaryotes, and further development of measures controlling infections they cause
Knowledge and attitude of key community members towards tuberculosis: mixed method study from BRAC TB control areas in Bangladesh
This article was published in BMC Public Health [© 2015 BioMed Central Ltd.] and the definite version is available at: http://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-015-1390-5Background: Bangladesh National Tuberculosis (TB) Control Programme adopted a number of strategies to facilitate TB diagnosis and treatment. 'Advocacy, Communication and Social Mobilization' (ACSM) was one of the key strategies implemented by BRAC (Bangladesh Rural Advancement Committee, a non-governmental development organization) TB control program. The purpose of this study is to assess the knowledge and attitudes of the key community members (KCMs) participated in ACSM in BRAC TB control areas. Methods: This study combined quantitative and qualitative methods using a mixed method approach. KCMs in three districts with low TB case detection rates were targeted to assess the ACSM program. The quantitative survey using a multi-stage random-sampling strategy was conducted among 432 participants. The qualitative study included in-depth interviews (IDIs) of a sub sample of 48 respondents. For quantitative analysis, descriptive statistics were reported using frequencies, percentages, and Chi square tests, while thematic analysis was used for qualitative part. Results: Most (99%) of the participants had heard about TB, and almost all knew that TB is a contagious yet curable disease. More than half (53%) of the KCMs had good knowledge regarding TB, but BRAC workers were found to be more knowledgeable compared to other KCMs. However, considerable knowledge gaps were observed among BRAC community health workers. Qualitative results revealed that the majority of the KCMs were aware about the signs, symptoms and transmission pathways of TB and believed that smoking and addiction were the prime causes of transmission of TB. The knowledge about child TB was poor even among BRAC health workers. Stigma associated with TB was not uncommon. Almost all respondents expressed that young girls diagnosed with TB. Conclusions: This study finding has revealed varying levels of knowledge and mixed attitudes about TB among the KCMs. It also provides insight on the poor knowledge regarding child TB and indicate that despite the significant success of the TB program stigma is yet prevalent in the community. Future ACSM activities should engage community members against stigma and promote child TB related information for further improvement of BRAC TB Control Programme
Sustainable green nanoadsorbents for remediation of pharmaceuticals from water and wastewater: A critical review
In the last three decades, pharmaceutical research has increased tremendously to offer safe and healthy life. However, the high consumption of these harmful drugs has risen devastating impact on ecosystems. Therefore, it is worldwide paramount concern to effectively clean pharmaceuticals contaminated water streams to ensure safer environment and healthier life. Nanotechnology enables to produce new, high-technical material, such as membranes, adsorbent, nano-catalysts, functional surfaces, coverages and reagents for more effective water and wastewater cleanup processes. Nevertheless, nano-sorbent materials are regarded the most appropriate treatment technology for water and wastewater because of their facile application and a large number of adsorbents. Several conventional techniques have been operational for domestic wastewater treatment but are inefficient for pharmaceuticals removal. Alternatively, adsorption techniques have played a pivotal role in water and wastewater treatment for a long, but their rise in attraction is proportional with the continuous emergence of new micropollutants in the aquatic environment and new discoveries of sustainable and low-cost adsorbents. Recently, advancements in adsorption technique for wastewater treatment through nanoadsorbents has greatly increased due to its low production cost, sustainability, better physicochemical properties and high removal performance for pharmaceuticals. Herein, this review critically evaluates the performance of sustainable green nanoadsorbent for the remediation of pharmaceutical pollutants from water. The influential sorption parameters and interaction mechanism are also discussed. Moreover, the future prospects of nanoadsorbents for the remediation of pharmaceuticals are also presented
Chromatin remodeller SMARCA4 recruits topoisomerase 1 and suppresses transcription-associated genomic instability
Topoisomerase 1, an enzyme that relieves superhelical tension, is implicated in transcription-associated mutagenesis and genome instability-associated with neurodegenerative diseases as well as activation-induced cytidine deaminase. From proteomic analysis of TOP1-associated proteins, we identify SMARCA4, an ATP-dependent chromatin remodeller; FACT, a histone chaperone; and H3K4me3, a transcriptionally active chromatin marker. Here we show that SMARCA4 knockdown in a B-cell line decreases TOP1 recruitment to chromatin, and leads to increases in Igh/c-Myc chromosomal translocations, variable and switch region mutations and negative superhelicity, all of which are also observed in response to TOP1 knockdown. In contrast, FACT knockdown inhibits association of TOP1 with H3K4me3, and severely reduces DNA cleavage and Igh/c-Myc translocations, without significant effect on TOP1 recruitment to chromatin. We thus propose that SMARCA4 is involved in the TOP1 recruitment to general chromatin, whereas FACT is required for TOP1 binding to H3K4me3 at non-B DNA containing chromatin for the site-specific cleavage
Computational investigation of solar updraft tower for power generation in sultanate of Oman
837-843The current study is aimed at harnessing solar power through solar updraft tower (SUT) and explored the local environmental factors conducive to SUT installation. The SUT collects solar insolation to raise the air velocity, which is then allowed to pass through a ducted turbine. An alternator is installed with the air turbine to generate electricity. The study presents a performance analysis of SUT based on local thermal radiation and wind velocity. Three-dimensional numerical modelling of SUT is carried using computational fluid dynamics (CFD) solver. The model is validated with the experimental results available in the open literature. The collector temperature profile obtained through CFD modelling matches well with the experimental results. A maximum temperature rise of 20 ºC was ob-served in the collector modelled and solved numerically using CFD solver. The air velocity increases as the flow move from the collector periphery to the center of the SUT and reach to its maximum just before the center of the SUT. However, for the chimney, the temperature was observed to be increased continuously due to its continuous heating through the chimney walls, which receives solar radiation. The performance of SUT is examined with the change in inlet air velocity based on the local conditions in the Sultanate of Oman
Computational investigation of solar updraft tower for power generation in sultanate of Oman
The current study is aimed at harnessing solar power through solar updraft tower (SUT) and explored the local environmental factors conducive to SUT installation. The SUT collects solar insolation to raise the air velocity, which is then allowed to pass through a ducted turbine. An alternator is installed with the air turbine to generate electricity. The study presents a performance analysis of SUT based on local thermal radiation and wind velocity. Three-dimensional numerical modelling of SUT is carried using computational fluid dynamics (CFD) solver. The model is validated with the experimental results available in the open literature. The collector temperature profile obtained through CFD modelling matches well with the experimental results. A maximum temperature rise of 20 ºC was ob-served in the collector modelled and solved numerically using CFD solver. The air velocity increases as the flow move from the collector periphery to the center of the SUT and reach to its maximum just before the center of the SUT. However, for the chimney, the temperature was observed to be increased continuously due to its continuous heating through the chimney walls, which receives solar radiation. The performance of SUT is examined with the change in inlet air velocity based on the local conditions in the Sultanate of Oman
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