关键词： Fuel cells   Polymer electrolyte membrane   Direct methanol fuel cell   SANS   Monte Carlo simulation  

摘要： The use of fuel cells is strategic in the global energy system;their inclusion in eco-cars, avoiding CO2 emission, represents a crucial enhancement for the environment. For this reason, any improvement in their use and optimization is fundamental for our society. Since one of the main components in these cells is their polymeric proton exchange membrane, in this work, the commercial Fumapem F-14100 and F-1850 membranes have been studied, both representing a cheap and effective alternative in direct methanol fuel cell (DMFC) applications. Their characterization will provide a new insight about them, in order to optimize and improve future fuel cell operation conditions. Small angle neutron scattering (SANS) has been used in this work to achieve a nanometric structural characterization of these membranes, which is key for understanding their physicochemical properties. Starting from SANS measurements, empirical fitting models were applied in order to obtain global sample features, which allowed to propose a lamellar water channel structure. Then, 2D scattering length density maps generated by Monte Carlo simulations were optimized to match the experimental SANS intensity profiles by using the inverse Fourier transform method. In addition, the crystalline contribution from the sample ordered domains was also studied by using X-ray diffraction.

关键词： Aviation fuels   Fuel surrogate   Modeling   Flow reactor   Hydrogen deficiency  

摘要： In Part III of our study on alternative aviation fuels, we present a comprehensive database of modeled speciation data consisting of seven hydrocarbons of varying molecular structure and 26 alternative and conventional aviation fuels. The speciation data is obtained from the DLR atmospheric high temperature flow reactor with a coupled molecular beam mass spectrometry (MBMS) detection system (Part-I). The chemical reactivity of these real liquid fuels is investigated both experimentally and numerically. For modeling, detailed fuel surrogates (up to 14 components) are employed for characterizing the fuels. The surrogate formulation strategy is defined based on the fuels' compositional analysis. This work employs high temperature reaction kinetic mechanism for the combustion of wide variety of hydrocarbons of varying molecular classes from n-, iso-, cy-paraffins, to five-ring aromatics presented in Part-II. The reaction mechanism is applied to model 26 aviation fuels using 21 different validated fuel surrogate components to predict the fuel intermediates and soot precursors measured in the reactor. This work aims to identify the effect of fuel surrogate components on the intermediates' formation and its influence on the emissions. Through compilation of many fuels with composition of wide range of chemical classes, we provide a systematic evaluation of how the fuel composition can be used to extract information of specific fuel intermediates and emissions formed.

关键词： Throughput  

摘要： We present a review of the field of high-throughput virtual screening for organic electronics materials focusing on the sequence of methodological choices that determine each virtual screening protocol. These choices are present in all high-throughput virtual screenings and addressing them systematically will lead to optimised workflows and improve their applicability. We consider the range of properties that can be computed and illustrate how their accuracy can be determined depending on the quality and size of the experimental datasets. The approaches to generate candidates for virtual screening are also extremely varied and their relative strengths and weaknesses are discussed. The analysis of high-throughput virtual screening is almost never limited to the identification of top candidates and often new patterns and structure-property relations are the most interesting findings of such searches. The review reveals a very dynamic field constantly adapting to match an evolving landscape of applications, methodologies and datasets.

关键词： RNA processing   alternative polyadenylation   DNA damage   apoptosis   MSL   PCF11   cisplatin   cancer   chemotherapy   p53  

摘要： DNA damage reshapes the cellular transcriptome by modulating RNA transcription and processing. In cancer cells, these changes can alter the expression of genes in the immune surveillance and cell death pathways. Here, we investigate how DNA damage impacts alternative polyadenylation (APA) using the PAPERCLIP technique. We find that APA shifts are a coordinated response for hundreds of genes to DNA damage, and we identify PCF11 as an important contributor of DNA damage-induced APA shifts. One of these APA shifts results in upregulation of the full-length MSL1 mRNA isoform, which protects cells from DNA damage-induced apoptosis and promotes cell survival from DNA-damaging agents. Importantly, blocking MSL1 upregulation enhances cytotoxicity of chemotherapeutic agents even in the absence of p53 and overcomes chemoresistance. Our study demonstrates that characterizing adaptive APA shifts to DNA damage has therapeutic implications and reveals a link between PCF11, the MSL complex, and DNA damage-induced apoptosis.

关键词： Microstructure characterisation   Microstructure reconstruction   Pore structure   BSE image   Image analysis  

摘要： The porous structure of hydrated cement has a significant effect on its governing properties, such as strength, density, ion-diffusion, acoustic performance etc. However, direct observation of the 3D pore structure is limited by high stochasticity and multiscale features. We constructed a statistically equivalent 3D micropore structure using a digital concrete model that used a probabilistic map derived from 2D cross-sections and parameter sets calibrated via a deep learning neural network. Based on the replica of cement pore structure, image analyses and virtual mercury intrusion porosimetry (MIP) tests were compared with experimental outcomes. In particular, the pore size distribution curves matched well for both MIP and image analysis approaches. However, although the fractal dimension derived from each 2D image linearly correlated with the corresponding porosity, it tended to underestimate the complexity of the pore structure. Correspondingly, the 3D fractal dimension showed a periodic pattern to voxel size in log-scale and was slightly higher than the MIP results. The tortuosity factor also had a linear correlation to voxel size, resulting in an overestimation of the pore structure's tortuosity. We demonstrated that the digital concrete model could serve as an alternative approach to studying the microstructural pore analysis of cementitious material through such a comparison. This study's outcome helps to understand the structure-property link in cement with the potential to transform traditional analytical processes of cementitious materials.

摘要： Epstein-Barr virus (EBV) is a human herpesvirus associated with human cancers worldwide. Ex vivo, the virus efficiently infects resting human B lymphocytes and induces their continuous proliferation. This process is accompanied by a global reprogramming of cellular gene transcription. However, very little is known on the impact of EBV infection on the regulation of alternative splicing, a pivotal mechanism that plays an essential role in cell fate determination and is often deregulated in cancer. In this study, we have developed a systematic time-resolved analysis of cellular mRNA splice variant expression during EBV infection of resting B lymphocytes. Our results reveal that major modifications of alternative splice variant expression appear as early as day 1 post-infection and suggest that splicing regulation provides-besides transcription-an additional mechanism of gene expression regulation at the onset of B cell activation and proliferation. We also report a role for the viral proteins, EBNA2 and EBNA-LP, in the modulation of specific alternative splicing events and reveal a previously unknown function for EBNA-LP-together with the RBM4 splicing factor-in the alternative splicing regulation of two important modulators of cell proliferation and apoptosis respectively, NUMB and BCL-X.

关键词： 小学体育   学科整合   有效策略  

摘要： 学科整合是指通过知识之间的相互联系把不同类型的学科进行整合,是指不同学科彼此有相互的关联性.教师在课堂教学中，要制作出合理的教学方案帮助学生学习积极性提升和对文化素养提供的同时，并且也要关注对其他方面的提高,比如包括社会适应整体能力和身体健康。

关键词： Ball milling  

摘要： Vanadium-substituted phosphomolybdic acids (H3+x[PMo12-xVxO40], denoted as V-x) are well-known oxidation catalysts that are generally prepared by the hydrothermal treatment of MoO3 and V2O5 in the presence of H3PO4. This synthesis procedure is highly energy consuming and the V-x yields are not always acceptable. In the present work, an alternative hybrid mechanochemical/hydrothermal synthesis of V-x is proposed, comprising the ball-milling of MoO3 and V2O5, followed by a hydrothermal attack. The resulting materials, with 2 <= x <= 3, obtained from this new route were compared, in terms of yield, energy consumption and catalytic activity, with a reference V-3 sample prepared through a conventional hydrothermal treatment. The ball-milling step proved to lead not only to a shorter and far more energy-saving synthesis procedure, but also to high yields of V-x. Moreover, V-x from this alternative route proved to be generally more active than the conventionally prepared V-3 in the aerobic oxidative cleavage of C-O and C-C bonds in 2-phenoxyacetophenone, used herein as a lignin model compound.

关键词： Acylation   C-H activation   Transition-metals   Metal-free   Photocatalysis  

摘要： Functionalizing and derivatising organic molecules is a centerpiece in organic synthesis. Succinctly manipulating and installing acyl moieties in organic molecules spurred the interest of chemists owing to its occurrence in natural products, bioactive molecules, pharmaceuticals, and advanced materials. Traditionally, access to acylation reaction was achieved by Friedel-Crafts reaction, Schotten-Baumann, and Vilsmeier-Haack acylation, however, these protocols own pitfalls. Further to make the acylation process attractive and environmentally friendly, toluene, aldehydes, alcohols, alpha-keto acids, amines, amides, esters, ethers, nitriles, alkynes, alkenes, ketenes, N-acylbenzotriazoles, ketones, thioacids, oximes, thiazolium carbinols, PIDA, diacyl disulfides and acyl salts were used as an acyl surrogates/reagents. Amusingly, these acylating reagents are considered uncommon and alternative to carboxylic acids, acid chlorides and acetic anhydrides. This short review aims to encompass the usage of acylating agents in transition-metal, metal-free, light-driven and other demanding conditions, and thus reveals their practicality.

关键词： Acetaminophen overdose   acetylcysteine regimen   toxicology   hepatotoxicity   drug safety  

摘要： Introduction Acetylcysteine is the standard treatment for preventing hepatotoxicity caused by acetaminophen overdose. Several novel approaches to the management of acetaminophen overdose have been suggested to improve patient safety by reducing adverse drug reactions and dosing errors. This article reviews these alternative treatment regimens and intends to offer a detailed assessment of the available options to assist providers in managing cases of acetaminophen overdose. Areas covered This review article covers observational and experimental studies that assessed the efficacy and safety of alternative intravenous acetylcysteine regimens for acetaminophen overdose. A literature search was conducted using PubMed, ProQuest, and Scopus to identify the studies, which included results through April 2021. The assessment of alternative regimens consists of a discussion on the limitations and benefits, barriers to implementation, and important considerations for each regimen. Expert opinion Several alternative regimens have been studied and implemented in various institutions. Many of these dosing regimens have supporting safety data but most lack robust data. A reduction in infusion-related side effects is an important outcome, but established efficacy, local poison center familiarity with the regimen, institutional resources, and patient-specific factors should be equally considered when deciding on implementing and using an alternative dosing strategy.