Structure Characterization and Lead Detoxification Effect of Carboxymethylated Melanin Derived from <Emphasis Type="Italic">Lachnum</Emphasis> Sp.

In the present study, an intracellular melanin, named LIM205, was separated from Lachnum YM205 mycelia and was purified on a Sephadex G-15 column. The molecular weight of LIM205 was determined as 522 Da, and its molecular formula was speculated as C₂₈H₁₄N₂O₇S. The possible chemical structure of LIM205 was determined according to the results of Fourier transform infrared (FT-IR), ¹H NMR, ¹³C NMR, and pyrolysis/GC-MS analysis. With the aim to increase its water solubility, its carboxymethylated derivative, named CLIM205, was formed by the substitution of hydrogen atoms in LIM205 with one, two, and three carboxymethylate groups. FT-IR, UV, and ESI-MS analysis demonstrated that the carboxymethylate groups were conjugated onto LIM205. The lead detoxification activities of LIM205 and CLIM205 had also been investigated. In vivo test showed that both LIM205 and CLIM205 reduced the tissue lead concentration, enhanced lead excretion, and reversed lead-induced alterations in superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) concentrations in mice, with CLIM205 showed better efficacy. The study indicates that LIM205 and CLIM205 have significant lead detoxification effect which will contribute to solve related problems.     

Hydrogen evolution assisted deposition of a three-dimensional porous nickel film for the electrocatalytic oxidation of histamine

Microchimica Acta - The authors describe an electrochemical sensor for ultrasensitive voltammetric of histamine (HA) by using a gold electrode that was modified with a film consisting of...     

蒸氨法制备铜硅催化剂的二甲醚水蒸气重整制氢性能

采用蒸氨法制备出不同Cu负载量的xCu/SiO_2-AE催化剂,并将其用于二甲醚水蒸气重整制氢反应。当Cu负载量为30%(w)时,30Cu/SiO_2-AE催化剂表现出最佳的催化性能。结果显示,该方法制备的催化剂表面具有高度分散的CuO和层状硅酸铜物相,经还原后分别形成Cu~0和Cu~+物种。与常规浸渍法制备的30Cu/SiO_2-IM催化剂相比,蒸氨法制备的30Cu/SiO_2-AE催化剂具有优异的催化稳定性和活性,这与其独特的层状结构和表面Cu~0与Cu~+之间的协同作用相关。     

二氧化碳直接高选择性合成液体燃料

正作为主要温室气体的CO_2,也是一种自然界大量存在的碳资源,若能借助太阳能和风能等可再生能源获取电能分解水制得的氢气,将CO_2转化为化学品或燃料,不仅能实现温室气体的减排,而且有助于解决对化石燃料的过度依赖以及可再生能源的存储问题~1。作为一类高碳烃类     

石墨烯基复合材料应用于光电二氧化碳还原的基本原理，研究进展和发展前景

In response to aggravated fossil resources consuming and greenhouse effect, CO₂ reduction has become a globally important scientific issue because this method can be used to produce value-added feedstock for application in alternative energy supply. Photoelectrocatalysis, achieved by combining optical energy and external electrical bias, is a feasible and promising system for CO₂ reduction. In particular, applying graphene in tuning photoelectrochemical CO₂ reduction has aroused considerable attention because graphene is advantageous for enhancing CO₂ adsorption, facilitating electrons transfer, and thus optimizing the performance of graphene-based composite electrodes. In this review, we elaborate the fundamental principle, basic preparation methods, and recent progress in developing a variety of graphene-based composite electrodes for photoelectrochemical reduction of CO₂ into solar fuels and chemicals. We also present a perspective on the opportunities and challenges for future research in this booming area and highlight the potential evolution strategies for advancing the research on photoelectrochemical CO₂ reduction.     

硝酸肼的量热研究

用精密自动绝热量热计测定了在220 K—370 K温度范围内硝酸肼的热容、熔化热、熔化温度和熔化熵。所得热容数据的精密度以百分偏差的均方根值表示为±0.2％。三次熔化热测定的相对偏差为±0.1％。为验证结果的可靠性, 用该装置测定了冰的熔化热和熔化温度, 其结果与文献值一致; 又用法国SETARAM公司的高温量热计测定了硝酸肼的熔化热和熔化温度, 其结果与我们用量热法测定的结果一致; 从量热结果计算出了该试样的纯度, 该结果亦与化学分析的结果一致。这些均可说明我们所测得的数据是可靠的。     

Suspending Ion Electrocatalysts in Charged Metal–Organic Frameworks to Improve the Conductivity and Selectivity in Electroorganic Synthesis

Electroorganic synthesis is an environmentally friendly alternative to traditional synthetic methods; however, the application of this strategy is heavily hindered by low product selectivity. Metal–organic frameworks (MOFs) exhibit high selectivity in numerous catalytic reactions; however, poor conductivity heavily limits the application of MOFs in electroorganic synthesis. To realize the electrocatalytic application of MOFs in selective electroorganic synthesis, a practically applicable strategy by suspending ion electrocatalysts in charged MOFs is herein reported. This approach could markedly improve the product selectivity in electroorganic synthesis. In the electrocatalytic oxidative self‐coupling of benzylamine experiments, the imine product selectivity is markedly improved from 61.3 to 94.9 %, when the MOF‐based electrocatalyst is used instead of the corresponding homogeneous electrocatalyst under the identical conditions. Therefore, this work opens a new route to improve the product selectivity in electroorganic synthesis.     

Stereoconvergent,Redox‐Neutral Access to Tetrahydroquinoxalines through Relay Epoxide Opening/Amination of Alcohols

We present an economical catalytic procedure to convert readily available 1,2‐diaminobenzenes and terminal epoxides into valuable 1,2,3,4‐tetrahydroquinoxalines in a highly enantioselective fashion. This procedure operates through relay zinc and iridium catalysis, and achieves redox‐neutral and stereoconvergent production of valuable chiral heterocycles from racemic starting materials with water as the only side product. The use of commercially available reagents and catalysts and a convenient procedure also make this catalytic method attractive for practical application.     

Solid acids assisted matrix solid‐phase dispersion microextraction of alkaloids by capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry

The quantification of three alkaloids is important because quantitative study is a means of assessing the reliability of the experimental method, and three alkaloids of peimine, peiminine, and peimisine are main active ingredients in Chinese Pharmacopoeia 2015. An effective method based on the matrix solid‐phase dispersion microextraction was developed for the extraction of alkaloid compounds in Fritillariae Thunbergii Bulbus. Target analytes were analyzed by capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry. The optimized experimental condition was that 50 mg Fritillariae Thunbergii Bulbus was blended homogeneously with 10 mg citric acid for 5 min. Two hundred microliters of water acidized by 1 mol/L hydrochloric acid (pH = 4.5) was selected to elute tested alkaloids. The results demonstrated that the investigated method had low limits of detection (1.32–1.59 ng/mL), good recoveries (86.63–98.12%), and reproducibility (relative standard deviations of peak areas < 0.87%). The proposed matrix solid‐phase dispersion microextraction coupled with capillary electrophoresis combined with quadrupole time‐of‐flight mass spectrometry was successfully applied for the extraction of alkaloids in plants.