pearwing6670 の編集

Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme involved in REDOX reactions and oxidative stress defense systems. Furthermore, NAD is used as substrate by proteins that regulate essential cellular functions as DNA repair, genetic, and signal transduction, among many others. NAD biosynthesis can be completed through the de novo and salvage pathways, which converge at the common step catalyzed by the nicotinate/nicotinamide mononucleotide adenylyltransferase (NMNAT EC 2.7.7.1/18). Here, we report the kinetic characterization of the NMNAT of Leishmania braziliensis (LbNMNAT), one of the etiological agents of leishmaniasis, a relevant parasitic disease. The expression and homogeneous purification of the recombinant 6xHis-LbNMNAT protein was carried out and its kinetic study, which included analysis of K m , V max , K cat and the equilibrium constant (K D ) for both the forward and reverse reactions, was completed. The oligomeric state of the recombinant 6xHis-LbNMNAT protein was studied through size exclusion chromatography. Our results indicated the highest and lowest K m values for ATP and NAD, respectively. According to the calculated K D , the pyrophosphorolytic cleavage of NAD is favored in vitro. Moreover, the recombinant 6xHis-LbNMNAT protein showed a monomeric state, although it exhibits a structural element involved in potential subunits interaction. Altogether, our results denote notable differences of the LbNMNAT protein in relation to the human orthologs HsNMNAT1-3. These differences constitute initial findings that have to be continued to finally propose the NMNAT as a promissory pharmacological target in L.&nbsp;braziliensis. © 2020 The Author(s).Trade liberalization led to the flooding of the Nigerian markets with ''made in China'' children's toys. Information about metal contamination in toys is vital to ensure the safety of children's product. This is a pediatric health risk assessment of three toxic metals (Pb, Cd and As) in children toys purchased from Nigerian market. Thirty cheap ''made in China'' toys were purchased from stores in Port Harcourt, Nigeria. Three toxic metals (Pb, Cd and As) in the thirty toys samples were determined by absorption spectrophotometry. Pb, Cd and As were present in all the toys at levels below the limits set by EU. The oral and dermal exposure risk assessment showed no significant non-carcinogenic and carcinogen health risks of public health concern. Some ''made in China'' toys imported into Nigeria may not add to the body burden of these metals in children. © 2020 Published by Elsevier Ltd.The proliferation of ICT in South African basic education has not been associated with effective pedagogical uses of ICT in classrooms. While there is differential deployment of ICT as cognitive tools of instruction in South Africa's schools, the effects of educators' ICT self-efficacy on their pedagogical use of technologies is yet to be fully grasped. This research gap has been attributed to, inter alia, the lack of a detailed profile of ICT self-efficacy beliefs of educators and its effects on pedagogical uses of ICT by educators. This study employs a cross-sectional survey, adapting a structured questionnaire to investigate the relationship between purposively selected 163 Gauteng educators' ICT self-efficacy beliefs and their pedagogical use of ICT. https://www.selleckchem.com/products/sm-102.html An exploratory factor analysis on pedagogical use of ICT (PUI) revealed three factors of 'traditional PUI' and one 'constructivist PUI'. Results suggest that ICT self-efficacy had a positive significant but moderate effect on the three traditional PUI and a positive significant and strong relationship with the constructivist PUI. Furthermore, a linear regression analysis found ICT self-efficacy to significantly predict all four PUI factors. The study recommends initial educator training that emphasises exposure of trainee educators to extended periods of hands-on engagement with ICTs in classroom environments. Furthermore, it recommends continuous ICT integration and the development of practicing educators with a focus on the "how to" integrate ICT tools as 'generative' mind tools. These interventions have potential to increase educators' ICT self-efficacy in resource constrained contexts. The implication is that educator training curricula are re-designed with an emphasis on practical lesson planning that includes ICTs as seamless resources used in the classroom in basic education. © 2020 The Authors.Public transportation agencies are one of the industries that generate a large volume of data on a high frequency and velocity basis. The General Transit Feed Specification (GTFS) is one of the datasets these agencies generate and share openly with the public. GTFS feeds contain data for scheduled transit service including stop and route locations, and schedules information. This paper aims to demonstrate the potential of GTFS data, specifically, the paper describes the development of a GTFS data visualization tool that displays spatial and temporal patterns of transit services from which qualitative information and insights can be gained. In this paper, GTFS data from Calgary Transit was used as a case study. Previous studies focused on the development of visualization tools that display transit movement, or static graphical representation of transit operation. However, there is still a need for a dynamic interactive visualization tool that can also measures and displays transit system operation geographically and statistically. This study builds on the previous investigations and further develops a new public transit system operation visualization tool (called PubtraVis) with six visualization modules that reflect on different transit system operational characteristics; mobility, speed, flow, density, headway, and analysis. The user can evaluate two modules side by side for comparative analysis. The analysis module provides an insightful statistical summary and similarity measure and clustering results based on the transit operation characteristics. PubtraVis was tested with real-world users through a user experience study from which it was found to be useful and easy to start using. PubtraVis can be a useful tool to demonstrate the dynamism of transit vehicles from the entire transit network at a glance, and can be used to facilitate communication between transit operators, city authorities, and the general public regarding the public transit planning and operation. © 2020 The Authors.

タイムスタンプを変更しない

テキスト整形のルールを表示する