768 research outputs found
COVID-19 knowledge and perception among healthcare professionals in two Arabian Gulf countries
Introduction: The WHO announced on 30 January 2020 the respiratory tract infection outbreak caused by
Coronavirus 2019 (COVID-19) that was first recognized in China to be a global public health emergency.
Objective: To investigate healthcare professional's knowledge and awareness about COVID-19. Methods: The
study was conducted across four hospitals in Saudi Arabia and two hospitals in Kuwait. The questionnaire was
completed between 18th May and the end of June 2020. Results: A total of 460 healthcare professionals completed
the questionnaire, 37.8%(n=174) were males. The age of the participants ranged from 18 to 64 and 80.4% (n=370)
of the participants were aged 34 or below. Official government websites 54.8% (n=252) and social media 43.3%
(n=199) were the major reliable information sources related to COVID-19. only 37% (n=170) mentioned that
the coronavirus disease could transmit through contact. In addition, only 42% (n=191) of the study participants
had the correct knowledge about the incubation period of the disease. Moreover, 43.5% (n=200) of the
participants were able to identify the symptoms of COVID-19. Conclusion: The study recommended the need
to focus more on educational and awareness programs targeting all healthcare professionals to ensure the best
practice and provide the optimal care
Improved movie recommendations based on a hybrid feature combination method
Recommender systems help users find relevant items efficiently based on their interests and historical interactions with other users. They are beneficial to businesses by promoting the sale of products and to user by reducing the search burden. Recommender systems can be developed by employing different approaches, including collaborative filtering (CF), demographic filtering (DF), content-based filtering (CBF) and knowledge-based filtering (KBF). However, large amounts of data can produce recommendations that are limited in accuracy because of diversity and sparsity issues. In this paper, we propose a novel hybrid method that combines user–user CF with the attributes of DF to indicate the nearest users, and compare four classifiers against each other. This method has been developed through an investigation of ways to reduce the errors in rating predictions based on users’ past interactions, which leads to improved prediction accuracy in all four classification algorithms. We applied a feature combination method that improves the prediction accuracy and to test our approach, we ran an offline evaluation using the 1M MovieLens dataset, well-known evaluation metrics and comparisons between methods with the results validating our proposed method
Improved Methods for Fluorescence Microscopy Detection of Macromolecules at the Axon Initial Segment
The axonal initial segment (AIS) is the subcellular compartment required for initiation of the action potential in neurons. Scaffolding and regulatory proteins at the AIS cluster with ion channels ensuring the integrity of electrical signaling. Interference with the configuration of this protein network can lead to profound effects on neuronal polarity, excitability, cell-to-cell connectivity and brain circuit plasticity. As such, the ability to visualize AIS components with precision provides an invaluable opportunity for parsing out key molecular determinants of neuronal function. Fluorescence-based immunolabeling is a sensitive method for morphological and molecular characterization of fine structures in neurons. Yet, even when combined with confocal microscopy, detection of AIS elements with immunofluorescence has been limited by the loss of antigenicity caused by fixative materials. This technical barrier has posed significant limitations in detecting AIS components alone or in combination with other markers. Here, we designed improved protocols targeted to confocal immunofluorescence detection of the AIS marker fibroblast growth factor 14 (FGF14) in combination with the cytoskeletal-associated protein Ankyrin-G, the scaffolding protein βIV-spectrin, voltage-gated Na+ (Nav) channels (especially the Nav1.6 isoform) and critical cell type-specific neuronal markers such as parvalbumin, calbindin, and NeuN in the mouse brain. Notably, we demonstrate that intracardiac perfusion of animals with a commercially available solution containing 1% formaldehyde and 0.5% methanol, followed by brief fixation with cold acetone is an optimal and sensitive protocol for FGF14 and other AIS marker detection that guarantees excellent tissue integrity. With variations in the procedure, we also significantly improved the detection of Nav1.6, a Nav isoform known for its fixative-sensitivity. Overall, this study provides an ensemble of immunohistochemical recipes that permit excellent staining of otherwise invisible molecules within well-preserved tissue architecture. While improving the specific investigation of AIS physiology and cell biology, our thorough study can also serve as a roadmap for optimizing immunodetection of other fixative-sensitive proteins expanding the repertoire of enabling methods for brain studies
The Impact of the Teacher’s Personality on the Motivation of Learning the English Language Among Governmental School Students in Saudi Arabia
The current study aimed to identify the impact of the teachers personality on the motivation of learning English among government school students in the city of Abha, Saudi Arabia. The descriptive correlative method was used, and two questionnaires were designed to collect the data. They were distributed electronically, and the study targeted a sample of English language teachers in public secondary schools in Abha, and a sample of high school students in Abha, who were chosen randomly in a simple way. The results of the study showed that English language teachers have personal characteristics that qualify them to teach in high government schools, with an average of (3.6918), which is considered as a highly - approved degree, and that students have a motivation to learn English with an average of (3.7828), which means they scored a high degree of approval. The results also showed the effect of the teachers personality on the motivation of students towards learning English. The results also showed that it is possible to predict the motivation of learning English through the teachers personality
Stretch-activated channels in heart valve cells
The aortic valve is a sophisticated structure that performs complex functions to preserve the unidirectional flow of blood and maintenance of myocardial function. Valve endothelial cells (VECs) cover the two surfaces of aortic valve cusps in a continuous layer consisting of the endocardium and the sinus wall endothelium. Valve interstitial cells (VICs) are a heterogeneous and dynamic population of cells that form the body of valve cusps and are located within the extracellular matrix. VECs experience continuous and different mechanical forces in both side and VICs are experience continuous and varying mechanical forces, including stretch. These mechanical forces are translated to the cells via electrochemical or biochemical signals through mechanotransduction pathways, which may include stretch-activated ion channels (SACs) which are membrane proteins capable of responding to mechanical force and activate intracellular signalling pathways that mediate the functional response of the cells. The overall aim of this study was to investigate SACs presence and their functional roles in VECs and VICs. The presence of stretch-activated ion channels was studied electrophysiologically and biochemically in VECs from each side of the valve and different phenotypes of VICs. The role of SAC on alignment of and proliferation VECs, migration and collagen production in VICs were assessed. Stretch-activated ion channels receptors including (KCNK2, KCNJ8, TRPM4, TRPV4 and TRPC6) were present in VECs and VICs. SACs have the same channel activity in VECs from aortic and ventricular sides, but the expression level of some SACs are significantly more in VECs isolated from the ventricular side. Additionally, functional roles of SACs in VECs was demonstrated where blocking of SACs significantly reduced VECs alignment under shear stress. SACs activity and expression varied in VICs of a fibroblast, myofibroblast and osteoblast phenotype, which correlated with changes in fibroblast and osteoblast markers. SACs blockers significantly reduced migration and collagen production of VICs in response to mechanical stretch. Also, SACs activators regulated VICs proliferation in static condition. In conclusion, SACs are present in VECs and VICs and have regulatory roles in some mechanically-mediated cells responses or function. This study shows a role for SACs in the mechanobiology of valve cells, and information provides a new insight towards understanding valve cell function in health and disease.Open Acces
Cytotoxic Activity of Non-specific Lipid Transfer Protein (nsLTP1) from Ajwain \u3cem\u3e(Trachyspermum ammi)\u3c/em\u3e Seeds
Background
Trachyspermum ammi, commonly known as Ajwain, is a member of the Apiaceae family. It is a therapeutic herbal spice with diverse pharmacological properties, used in traditional medicine for various ailments. However, all previous studies were conducted using small molecule extracts, leaving the protein’s bioactivity undiscovered. Aim
The current study aimed to demonstrate the cytotoxic activity of Ajwain non-specific lipid transfer protein (nsLTP1) in normal breast (MCF10A), breast cancer (MCF-7), and pancreatic cancer (AsPC-1) cell lines. Also, to evaluate its structural stability in human serum as well as at high temperature conditions. Methods
The cytotoxic activity of Ajwain nsLTP1 was evaluated in MCF-7 and AsPC-1 cell lines using MTT assay. Annexin V-FITC and PI staining were used to detect the early apoptotic and late apoptotic cells. The role of nsLTP1 in inducing apoptosis was further studied by quantifying Bcl-2, Bax, Caspase-3, Survivin, EGFR, and VEGF genes expression using RT-PCR. CD spectroscopy analyzed the nsLTP1 conformational changes after thermal treatment for structure stability determination. The RP-HPLC was used to analyze the nsLTP1 degradation rate in human serum at different time intervals incubated at 37 °C. Results
Ajwain nsLTP1 showed a potent cytotoxic effect in MCF-7 and AsPC-1. The IC50 value obtained in MCF-7 was 8.21 μM, while for AsPC-1 4.17 μM. The effect of nsLTP1 on stimulating apoptosis revealed that the proportions of apoptotic cells in both cell lines were relatively increased depending on the concentration. The apoptotic cells percentage at 20 μM was in MCF-7 71% (***P \u3c 0.001) and AsPC-1 88% (***P \u3c 0.001). These results indicate that nsLTP1 might efficaciously induce apoptosis in multiple types of cancerous cells. Genes expression in MCF-7 and AsPC-1 showed significant upregulation in Bax and Caspase-3 and downregulation in Bcl-2, Survivin, EGFR, and VEGF protein. The CD analysis of nsLTP1 showed a significant thermostable property. In serum, nsLTP1 showed a slow degradation rate, indicating high stability with a half-life of ~ 8.4 h. Conclusion
Our results revealed the potential anticancer activity of Ajwain nsLTP1 and its mechanism in inducing apoptosis. It further exhibited thermostable properties at high temperatures and in human serum, which suggested this protein as a promising anticancer agent
Prevalence of intestinal parasitic infections among university female students, Gaza, Palestine
The intestinal parasites are still endemic among children, women, and men in Gaza Strip. To the best of our knowledge, this is the first study of intestinal parasites among young female students of Islamic University of Gaza to report the existence and prevalence of intestinal parasites. A total of 305 stool samples were collected from female students in all faculties and were examined by wet mount and formal ether sedimentation technique. This study showed that the overall prevalence of intestinal parasites was 20.6%. The detected intestinal parasites were as follows: (7.5%), (4.9%), (0.3%), (2.6%), (1.0%), and (3.9%). Science students showed the highest prevalence for parasitic infections (35.3%), and married students (16.7%) had higher prevalence than single students (6.5%). It was concluded that female students also are under risk of gaining parasitic infection in spite of their education. It is recommended that university students should be subjected to regular medical examinations for parasitic infections. [Abstract copyright: Copyright: © 2019 Avicenna Journal of Medicine.
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Radial turbine expander design for organic rankine cycle, waste heat recovery in high efficiency, off-highway vehicles
Although state-of-the-art, heavy duty diesel engines of today can reach peak thermal efficiencies of approximately 45%, still most of the fuel energy is transformed into wasted heat in the internal combustion process. Recovering this wasted energy could increase the overall thermal efficiency of the engine as well as reduce the exhaust gas emissions. Compared to other Waste Heat Recovery (WHR) technologies, Organic Rankine Cycle (ORC) systems are regarded favourably due to their relative simplicity and small back pressure impact on engine performance and fuel consumption. The key elements affecting the efficiency of the ORC system are the type of working fluid selected and the design of the expander. In this simulation study, a zero-dimensional, design code has been developed to explore the impact of two, common, refrigerant working fluids on the design of a radial turbine expander. In addition, an off-design turbine analysis has been applied in order to evaluate the performance of the expander in the ORC cycle at various engine operating points. Moreover, the evaluation of ORC-diesel engine on improving fuel consumption, brake power, brake torque and exhaust gas emissions is investigated. Compared to a conventional diesel powertrain system, WHR showed an up to 5.7 % increase in brake torque and brake power and a 5.4% reduction in the brake specific fuel consumption (bsfc). The results also showed that the working fluid selection and the expander speed are critical parameters on the performance of the proposed hybrid powertrain configuration
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