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971.
Seung Hyo Kim Kwang Hee Kim Prof. Dr. Soon Hyeok Hong 《Angewandte Chemie (International ed. in English)》2014,53(3):771-774
A carbon capture and use (CCU) strategy was applied to organic synthesis. Carbon dioxide (CO2) captured directly from exhaust gas was used for organic transformations as efficiently as hyper‐pure CO2 gas from a commercial source, even for highly air‐ and moisture‐sensitive reactions. The CO2 capturing aqueous ethanolamine solution could be recycled continuously without any diminished reaction efficiency. 相似文献
972.
Tenuun Bayaraa Jose Gaete Dr. Samuel Sutiono Julia Kurz Dr. Thierry Lonhienne Prof. Jeffrey R. Harmer Prof. Paul V. Bernhardt Prof. Volker Sieber Prof. Luke Guddat Prof. Gerhard Schenk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(44):e202200927
There is an urgent global need for the development of novel therapeutics to combat the rise of various antibiotic-resistant superbugs. Enzymes of the branched-chain amino acid (BCAA) biosynthesis pathway are an attractive target for novel anti-microbial drug development. Dihydroxy-acid dehydratase (DHAD) is the third enzyme in the BCAA biosynthesis pathway. It relies on an Fe−S cluster for catalytic activity and has recently also gained attention as a catalyst in cell-free enzyme cascades. Two types of Fe−S clusters have been identified in DHADs, i.e. [2Fe−2S] and [4Fe−4S], with the latter being more prone to degradation in the presence of oxygen. Here, we characterise two DHADs from bacterial human pathogens, Staphylococcus aureus and Campylobacter jejuni (SaDHAD and CjDHAD). Purified SaDHAD and CjDHAD are virtually inactive, but activity could be reversibly reconstituted in vitro (up to ∼19,000-fold increase with kcat as high as ∼6.7 s−1). Inductively-coupled plasma-optical emission spectroscopy (ICP-OES) measurements are consistent with the presence of [4Fe−4S] clusters in both enzymes. N-isopropyloxalyl hydroxamate (IpOHA) and aspterric acid are both potent inhibitors for both SaDHAD (Ki=7.8 and 51.6 μM, respectively) and CjDHAD (Ki=32.9 and 35.1 μM, respectively). These compounds thus present suitable starting points for the development of novel anti-microbial chemotherapeutics. 相似文献
973.
高层框架分析的状态变量传递法 总被引:1,自引:0,他引:1
取高层框架柱端位移和对应的柱端力作为状态变量,利用传递矩阵和逐层分析的方法来分析以框架。文中取框架的每一层作为基本单元,建立基本单元端部的状态变量与相邻基本单元端部状态变量之间的转换关系。分析过程中,框架烽的增加仅增加上乘的次数,而待求的基本未知量的数目始终保持不变,从而提高了计算机分析问题的能力。 相似文献
974.
975.
Olivier Braun Clment Coquery Johann Kieffer Frdric Blondel Cdrick Favero Cline Besset Julien Mesnager Franois Voelker Charlne Delorme Dimitri Matioszek 《Molecules (Basel, Switzerland)》2022,27(1)
Humankind is facing a climate and energy crisis which demands global and prompt actions to minimize the negative impacts on the environment and on the lives of millions of people. Among all the disciplines which have an important role to play, chemistry has a chance to rethink the way molecules are made and find innovations to decrease the overall anthropic footprint on the environment. In this paper, we will provide a review of the existing knowledge but also recent advances on the manufacturing and end uses of acrylamide-based polymers following the “green chemistry” concept and 100 years after the revolutionary publication of Staudinger on macromolecules. After a review of raw material sourcing options (fossil derivatives vs. biobased), we will discuss the improvements in monomer manufacturing followed by a second part dealing with polymer manufacturing processes and the paths followed to reduce energy consumption and CO2 emissions. In the following section, we will see how the polyacrylamides help reduce the environmental footprint of end users in various fields such as agriculture or wastewater treatment and discuss in more detail the fate of these molecules in the environment by looking at the existing literature, the regulations in place and the procedures used to assess the overall biodegradability. In the last section, we will review macromolecular engineering principles which could help enhance the degradability of said polymers when they reach the end of their life cycle. 相似文献
976.
977.
化学科学与人类生活密不可分,对人类的可持续发展至关重要。若科技与伦理的关系不和谐,必定会影响到整个人类社会发展的和谐性。化学作为一门重要的自然科学,化学科技伦理在当前科技伦理教育中的重要地位日益突出,在教学中加强化学科技伦理教育具有非常重要的意义。 相似文献
978.
民族地区高校大学数学课程教学改革的研究与实践 总被引:1,自引:0,他引:1
在分析民族地区高校大学数学课程教学现状的基础上,指出加快实施教学改革的必要性与紧迫性,提出了改革的指导思想与基本原则、改革的基本思路与目标,总结了试点效果,明确了进一步推进改革的方向. 相似文献
979.
980.
STS教育在化学新课程中已成为新的内容。科学技术价值观、科学技术伦理和科学决策能力等STS教育目标的含义都较深远。对丰富的STS教育目标已经有人建立了独特的目标群,认识这些目标将会对我国基础教育化学新课程中STS教育产生重要的推动作用。 相似文献