4-溴苯甲醚用作锂离子电池过充保护添加剂的研究

通过在锂离子电池电解液中添加4-溴苯甲醚(4-Bromoanisole, 简称4BA)来提高锂离子电池的过充保护能力. 对电池分别进行了过充实验、循环伏安扫描、红外光谱分析、交流阻抗和容量特性测试, 实验结果表明, 在1 mol•L－1 LiPF6/EC＋DEC＋DMC(质量比1/1/1)中添加5% 的4BA(质量分数)时, 当外加电压为4.4 V(相对于Li/Li＋)时, 4BA开始发生电聚合反应且生成高分子聚合物膜, 使电池内阻增大而阻止电压的升高, 从而使电池处于比较安全的状态. 该体系正常充放电过程中, 添加5%的4BA对电池容量特性基本没有影响, 4BA 的防过充机理为阻断机理.     

Risk assessment, remedial decisions and the challenge to protect public health: the perchlorate case study

While scientists have a responsibility to defer judgment in the absence of conclusive data, public health and ecological protection require that government regulators make decisions based on available information. The risk assessment paradigm has evolved to help risk managers balance risks to public health with the cost of pollution control and remediation. Risk assessments are designed to be reasonably protective of public health, however the time and money required to develop and evaluate a robust scientific database can significantly delay regulatory action while exposures continue. The federal assessment of perchlorate, a component of rocket fuel and a thyroid toxicant, is presented here as a case study that demonstrates some of the limitations of risk assessment in protecting public health. Perchlorate was detected in a city well field that lies beneath a military training range at Aberdeen Proving Ground, a U.S. Army garrison in Maryland. Cleanup was put on hold, pending promulgation of a national drinking water standard for perchlorate. This case study (1) illustrates the challenge of preventing chemical exposures in the absence of promulgated standards, and (2) makes recommendations for approaches to preventing exposures to chemicals of unknown, or uncertain toxicity before they occur.     

中药活性成分研究是中药现代化的重要组成部分

中药现代化是一个逐步发展、不断完善和充实的长期的系统工程。中医药在我国民族生存和繁衍的几千年历程中起着至关重要的作用,具有自己的特色和优势,是中华民族的宝贵财富,既要继承,又要创新和发展。中药现代化可以有多种模式,只要有利于人民健康,有利于传承和发展中医药,不管采取何种模式均应得到鼓励和欢迎。中药的活性成分研究是中药现代化的重要组成部分：一方面,一些活性成分能直接或作为先导化合物间接发展成药物;另一方面,活性成分又为中药复方现代化提供物质基础。这体现在活性成分既在现代化中药的制造和生产中起到标准化作用,同时活性成分也是中药复方专利最重要的核心组成部分。     

边界元方法计算牺牲阳极的接水电阻

本文在建立了阴极保护电位场数学模型的基础上，以边界元方法模拟牺牲阳极与低碳钢直接偶合时牺牲阳极的工作状态。     

Cochlear Synaptopathy Following Noise Exposure in Guinea Pigs: Its Electrophysiological and Histological Assessments

Exposure to high level of noise, may cause the permanent cochlear synaptic degeneration. In present study, a model of noise induced cochlear synaptopathy was established and the electrophysiological and histological metrics for its assessment was designed. 6 guinea pigs were subjected to a synaptopathic noise (octave band of 4 kHz at 104 dB SPL, for 2-h). The amplitude growth curve of Auditory Brainstem Response (ABR) wave-I and wave-III latency shift in presence of noise were calculated. These indexes were considered in pre-exposure, 1 day post exposure (1DPE), 1 week post exposure (1WPE) and 1 month post exposure (1MPE) to noise. Finally, the samples were histologically analyzed. ABR wave-I amplitude was different between pre and 1DPE (p-value ≤ 0.05). However, at 1WPE, it was recovered at low intensities but at 70 dB SPL and above, the differences persisted even till 1MPE. In masked ABR, the latency shift of wave-III was different between pre and 3 post exposure assessments (p-value ≤ 0.05). Electro-microscopic analysis confirmed the synaptic degeneration, as the ribbons were larger than normal, hollow inside, and spherical and irregular in shape, also, the post synaptic density was abnormally thick and missed its flat orientation. These data revealed that noise at level below that can produce permanent hearing loss, can incur synaptic injury. So, noise is considered to be more damaging than previously thought. Accordingly, designing tools for clinical assessment of synaptopathy is beneficial in comprehensive auditory evaluation of those with history of noise exposure and also in hearing protection planning.     

Insights into the Protective Effects of Thymoquinone against Toxicities Induced by Chemotherapeutic Agents

The drugs used to treat cancer not only kill fast-growing cancer cells, but also kill or slow the growth of healthy cells, causing systemic toxicities that lead to altered functioning of normal cells. Most chemotherapeutic agents have serious toxicities associated with their use, necessitating extreme caution and attention. There is a growing interest in herbal remedies because of their pharmacological activities, minimal side effects, and low cost. Thymoquinone, a major component of the volatile oil of Nigella sativa Linn, also known as black cumin or black seeds, is commonly used in Middle Eastern countries as a condiment. It is also utilized for medicinal purposes and possesses antidiabetic, anti-cancer, anti-inflammatory, hepatoprotective, anti-microbial, immunomodulatory, and antioxidant properties. This review attempts to compile the published literature demonstrating thymoquinone’s protective effect against chemotherapeutic drug-induced toxicities.     

古代青铜器的锈蚀与保护

考古发掘出的青铜器在外部条件及内部结构因素影响下,会出现不同程度的锈蚀现象。通过对古代青铜器的组成以及锈蚀产物的分析,对青铜器锈蚀的反应机理进行了探讨,并介绍了最新研究的保护方法。     

Targeted Synthesis of 3,3′-, 3,4′- and 3,6′-Phenylpropanoid Sucrose Esters

In this study, we report on an orthogonal strategy for the precise synthesis of 3,3′-, 3,4′-, and 3,6′-phenylpropanoid sucrose esters (PSEs). The strategy relies on carefully selected protecting groups and deprotecting agents, taking into consideration the reactivity of the four free hydroxyl groups of the key starting material: di-isopropylidene sucrose 2. The synthetic strategy is general, and potentially applies to the preparation of many natural and unnatural PSEs, especially those substituted at 3-, 3′-, 4′- and 6′-positions of PSEs.     

Dynamic Processes of Rhenium Polyhydride Complexes

Studies have demonstrated that high-coordination-number rhenium polyhydride complexes are precursors to catalysts that transform a variety of organic molecules. While rhenium polyhydride complexes lead to active catalysts, little has been reported on the mechanisms for the transformations. High-coordination-number rhenium polyhydride complexes exhibit several dynamic processes that make characterizations of the chemical properties for individual atoms difficult, at best, for room-temperature solutions. This review describes what is known of the dynamic processes that occur at high-coordination-number rhenium polyhydride complexes and how that knowledge may lead to the design of catalytic precursors in which the chemical properties of individual atoms can be more readily identified in room-temperature solutions.