Experimental and Computational Investigations into Trivalent Phosphorous-Mediated Radical Thiol Desulfurization

Radical-mediated thiol desulfurization processes using tricoordinate phosphorous reagents are used in a range of applications from small molecule synthesis to peptide modification. A combined experimental and computational examination of the mechanism and kinetics of the radical desulfurization of alkyl thiyl radicals using trivalent phosphorus reagents was performed. Primary alkyl thiols undergo desulfurization between 10^6 to 10^9 M-1s-1 depending on the phosphorus component with either an H-atom transfer step or β-fragmentation of the thiophosphoranyl intermediate may be rate-controlling. While the desulfurization of primary aliphatic thiols showed a marked dependence on the identity of phosphorous reagent used with either a rate-controlling H-atom transfer or -fragmentation, thiols yielding stabilized C-centered radicals showed much less sensitivity. Support for a stepwise S-atom transfer process progressing via a distorted trigonal bipyramidal thiophosphoranyl radical intermediate was obtained from DFT calculated energetics and hyperfine splitting values.

Direct observation of hyperpolarization breaking through the spin diffusion barrier

Dynamic nuclear polarization (DNP) is a widely used tool for overcoming the low intrinsic sensitivity of nuclear magnetic resonance spectroscopy and imaging. Its practical applicability is typically bounded, however, by the so-called “spin diffusion barrier,” which relates to the poor efficiency of polarization transfer from highly polarized nuclei close to paramagnetic centers to bulk nuclei. A quantitative assessment of this barrier has been hindered so far by the lack of general methods for studying nuclear polarization flow in the vicinity of paramagnetic centers. Here, we fill this gap and introduce a general set of experiments based on microwave gating that are readily implemented. We demonstrate the versatility of our approach in experiments conducted between 1.2 and 4.2 K in static mode and at 100 K under magic angle spinning (MAS)—conditions typical for dissolution DNP and MAS-DNP—and directly observe the marked dependence of polarization flow on temperature.

Los dispositivos móviles e Internet y su uso en el aula: ¿Un factor distractor en el proceso de aprendizaje? Un estudio de caso

Este estudio parte de la idea de que el manejo irresponsable de los dispositivos móviles y la Internet en los espacios académicos puede tener un efecto adverso en el proceso de aprendizaje de los estudiantes universitarios. La investigación se llevó a cabo con un grupo de estudiantes del Programa Educativo de la Licenciatura en Tecnologías de la Información, de la Facultad de Contaduría y Administración que oferta la Universidad Autónoma de Chihuahua. Se utilizó una metodología NO experimental, mixta, aplicada y descriptiva. Los resultados indican que los estudiantes muestran una marcada dependencia de estas herramientas tecnológicas cuando hacen un uso indiscriminado y NO responsable de ellas durante sus horas académicas, que incluso llega a modificar su actitud hacia el aprendizaje. Se observa que el uso del dispositivo móvil o el acceso a Internet en el aula cuando no se establece un límite para ello se convierte en un distractor para el estudiante en el cumplimiento de las actividades de aprendizaje que el docente pone en el aula, lo que redunda además de manera negativa en el desempeño académico del estudiante. En este contexto, si bien se aprecia el aspecto negativo del uso inmoderado de los dispositivos móviles y el Internet, si se advierte un área de oportunidad para promover una cultura de planeación académica en el uso de herramientas tecnológicas en los espacios académicos y establecer también lineamientos institucionales para ello. This study starts from the idea that the irresponsible handling of the mobile devices and the Internet in the academic spaces can have an adverse effect in the learning process of the university students. The research was carried out with a group of students of the Undergraduate Program in Information Technologies of the Faculty of Accounting and Administration, offered by the Autonomous University of Chihuahua. An experimental, mixed, applied and descriptive methodology was used. The results indicate that students show a marked dependence on these technological tools when they make an indiscriminate and non-responsible use of them during their academic hours, which even changes their attitude toward learning. It is observed that the use of the mobile device or the Internet access in the classroom, when no limits are established, becomes a distractor for the student in fulfilling the learning activities that the teacher guides in the classroom, which affects in a negative way in the academic performance of the student. In this context, however the negative aspect of the immoderate use of mobile devices and the Internet is appreciated, an area of opportunity is perceived to promote a culture of academic spaces and also establish institutional guidelines for this purpose.

Analyzing Scenarios for the Integration of Renewable Energy Sources in the Mexican Energy System—An Application of the Global Energy System Model (GENeSYS-MOD)

This paper uses numerical techno-economic modelling to analyse the effect of current national renewable targets and climate goals on the cost and structural composition of the Mexican energy system. For this, we construct a scenario base analysis to compare current policies with two alternative states of the world—one without climate policies and one attaining full decarbonization. Furthermore, an additional iterative routine allows us to estimate the cost-optimal share of renewable technologies in the energy sector and the effect that deviating from this share has on total discounted system costs, emissions and the structure of the energy mix. In general, model results exhibit three key insights—(1) A marked dependence of the energy system on photovoltaics and natural gas; (2) The 2050 cost-optimal share of renewables for the production of electricity, transportation and industrial heating is respectively 75%, 90% and 5%; and (3) As national renewable targets for the power sector are lower than the cost-optimal share of renewables, equivalent to the shares in an scenario without climate policies and completely disconnected from national climate goals, these should be modified.

Plants with pharmacological properties in the diet of wild ungulates of Polissya of Ukraine

In terms of forest ecosystems in Western Polesya, bordering cells of intensive livestock research started parazytofauny of game animals. Discovered possible cases of self healing of endoparasites animals. Established features seasonal diet of wild ungulates, including periodic eating plants have pharmacological properties and can be natural anthelmintics. Investigated the contents of stomachs and intestines of three species of hoofed animals (elk, roe deer European, wild boar) analysis of undigested remnants feed and plant selection helminthological material. Most attention was paid by identification of speciesof medicinal plants consumed by animals with clinical signs of helminths at critical times of the year. Marked dependence diet of ungulates from changes in climate, forage productivity of lands and epizootic situation in a number of helminths. There is also a possible link between the intensity of helminth infestations and the amount eaten plants that potentially have anti–parasitic properties. Determined about 30 species of plants and 2 species of mushrooms – possible medical components of the diet, which may be the subject of research in veterinary pharmacology and used in practice in the system of complex antiparasitic activities.

Uncritical and unbalanced coverage of synthetic biology in the Nordic press

Synthetic biology will probably have a high impact on a variety of fields, such as healthcare, environment, biofuels, agriculture, and so on. A driving theme in European research policy is the importance of maintaining public legitimacy and support. Media can influence public attitudes and are therefore an important object of study. Through qualitative content analysis, this study investigates the press coverage of synthetic biology in the major Nordic countries between 2009 and 2014. The press coverage was found to be event-driven and there were striking similarities between countries when it comes to framing, language use, and treated themes. Reporters showed a marked dependence on their sources, mainly scientists and stakeholders, who thus drives the media agenda. The media portrayal was very positive, with an optimistic look at future benefits and very little discussion of possible risks.

CD63 and GLUT-1 Overexpression Could Predict a Poor Clinical Outcome in GIST: A Study of 54 Cases with Follow-Up

Background and Goals.In light of current knowledge, it seems that alternations underlying GISTs are well explained, although all that is enhanced by various aspects on a daily basis. More recently, attention has been pointed towards exosomes as important particles able to modify healthy and also diseased tissues including cancer. The goal of the present study was an analysis of CD9, CD63, and GLUT-1 as a marker of hypoxia status within 54 cases of GIST and evaluation of their predictive value.Methods.54 cases of patients suffering from GIST were enrolled into the study, predominantly in the gastric location. All operated cases had no Imatinib and other chemotherapies up to the day of operation. Expression of targeted proteins was performed by immunohistochemistry and, after that, the results with tabulated clinical data were compared by Kaplan-Meier method and multivariate Cox proportional hazard model of statistical analysis.Results.Our results presented a marked dependence of worsening clinical outcome with high expression CD63 (p=0.008) as well as with GLUT-1 (p=0.014). We noted a strict correlation of GLUT-1 expression with CD63 expression (p=0.03), which could confirm the thesis about the contribution of exosomes in intratumoural hypoxia status. The collected material did not confirm CD9 contribution.Conclusions.As presented here, CD63 and GLUT-1 have a prognostic value in GIST cases. The results confirm the other studies in this scope and can be used in future as an additional prognostic factor.

Effects of Particle Size of Copper on the Electrical Property and Hardness of Copper/Graphite/Carbon Fiber/Phenolic Resin Composites

Composites made from phenolic resin are filled with conductive filler mixtures containing copper powders, natural graphite powders and carbon fibers. They are fabricated by compression molding technique. The density, electrical conductivity and hardness of composite are analyzed to determine the influence of copper particle size on the physical, electrical and mechanical properties of composite. It is found that there is a marked dependence of the electrical conductivity and hardness on copper particle size. The hardness decreases with the decreasing of copper particle size. However the electrical conductivity increases with the decreasing of copper particle size. The decreasing of copper particle size from 75 µm to 48 µm promotes a considerable increase in electrical conductivity by about 427%. The increased continuous conductive metal networks could be the main reason for the increasing of electrical conductivity as copper particle size decreases. The results also show that composites containing copper particles of different sizes have the nearly same density.

NOVEL AGENTS AND EMERGING STRATEGIES FOR TARGETING THE B-CELL RECEPTOR PATHWAY IN CLL

Chronic lymphocytic leukemia (CLL) is a disease of malignant CD5+ B lymphocytes that are characterized by frequent expression of autoreactive B-cell receptors (BCRs) and marked dependence on microenvironmental signals for proliferation and survival. Among the latter, signals propagated through the BCR are believed to play a key role in leukemia initiation, maintenance and evolution. Drugs that can disrupt these signals have recently emerged as potential therapeutic agents in CLL and several of them are currently being evaluated in clinical trials. Particularly promising clinical responses have been obtained with inhibitors of the kinases SYK, BTK, and PI3Kδ, which function by blocking BCR signal transduction. In addition, recent studies focusing on the phosphatase PTPN22, which is involved in the pathogenesis of multiple autoimmune diseases and is markedly overexpressed in CLL cells, suggest that it may be possible in the future to develop strategies that will selectively reprogram BCR survival signals into signals that induce leukemic cell death. This review focuses on the biological basis behind these strategies and highlights some of the most promising BCR-targeting agents in ongoing preclinical and clinical studies.