生物介质内形成的金属基生物微粒:冲击和挑战

在体液、组织、生物界面等生物介质中广泛存在着自发形成的金属基生物微粒,其中包括在体内原位生成的和异位转化的内源性微粒,也包括外源性微粒在体内被修饰转化所产生的次生微粒。这些在体内形成的微粒的粒径在纳米至微米级之间,它们大都参与生理、病理和毒理过程。但是目前缺乏对它们的生物效应与其形成、结构、性质相关性的研究。本文列举了有关金属基生物微粒的诸多现象和对它们的初步认识,提出了这方面有待解决的问题,这方面的研究结果将对环境、健康、疾病控制等领域的研究提供新思路。     

基于功能纳米材料的灵敏生物传感策略

21世纪的第一个十年被称为＂传感的十载＂.功能纳米材料为灵敏的生物传感器件（包括光学和电生物传感）的制备提供了优秀的平台.这方面的大多数工作主要聚焦于不同纳米材料的生物功能化,例如金属纳米粒子、半导体纳米粒子和碳纳米粒子,功能化方式包括物理吸附、静电结合、特异性识别或共价键合.这些生物功能化纳米材料可以用作催化剂、电导体、光发射剂、载体或示踪剂,以获取被放大的检测信号、稳定的识别探针或生物传感界面.设计的信号放大策略已经极大地促进了不同领域中稳定、特异、具有选择性和灵敏的生物传感器的发展.本文介绍了基于功能纳米材料的一些生物传感新原理和检测新策略,也讨论了纳米材料的生物功能化方法和生物传感在蛋白质的免疫分析、DNA检测、糖分析和细胞传感中的应用.     

生物炼制工业过程及产品

生物炼制是人类面对日益枯竭的化石资源和其所产生的严重环境污染的必然选择.本文从生物炼制和石油炼制的比较出发简要介绍了生物炼制的概念、基本分类和理论框架,并重点分析了生物炼制过程工程的相关技术和进展,主要包括生物质原料的预处理、过程相关的酶水解技术以及发酵菌种改良等.本文还概括了生物炼制相关的碳水化合物、脂肪类以及其他类产品的相关产品群,分析了一些重要生物基产品的生产过程、研发趋势以及所面临的机遇和挑战.     

生物炼制工业过程及产品

生物炼制是人类面对日益枯竭的化石资源和其所产生的严重环境污染的必然选择。本文从生物炼制和石油炼制的比较出发简要介绍了生物炼制的概念、基本分类和理论框架,并重点分析了生物炼制过程工程的相关技术和进展,主要包括生物质原料的预处理、过程相关的酶水解技术以及发酵菌种改良等。本文还概括了生物炼制相关的碳水化合物、脂肪类以及其他类产品的相关产品群,分析了一些重要生物基产品的生产过程、研发趋势以及所面临的机遇和挑战。     

氨基酸类生物降解聚合物的合成研究进展

聚氨基酸具有良好的生物相容性,其降解产物无毒,是一类重要的生物医用材料,本文评述了近年来此类聚合物合成方面的研究进展.     

利用可再生农林生物质资源的炼油厂——推动化学工业迈入“碳水化合物”新时代

本文首先介绍了国外以玉米、废弃生物质为原料发展生物炼油厂的设想;然后根据我国国情和已有技术基础,设想了以甜高梁、木薯为原料生产乙醇车用汽油和化工产品的生物炼油厂,以及以菜籽油、棉籽油为原料生产生物柴油和化工产品的生物炼油厂;最后探讨了遇到的问题和采取的对策。     

利用可再生农林生物质资源的炼油厂--推动化学工业迈入"碳水化合物"新时代

本文首先介绍了国外以玉米、废弃生物质为原料发展生物炼油厂的设想；然后根据我国国情和已有技术基础，设想了以甜高梁、木薯为原料生产乙醇车用汽油和化工产品的生物炼油厂，以及以菜籽油、棉籽油为原料生产生物柴油和化工产品的生物炼油厂；最后探讨了遇到的问题和采取的对策。     

生物催化制备香精香料

对于由细菌、真菌和酵母生产多种生物香精香料的潜力作了综述. 归纳了微生物工艺相对于化学合成或萃取的优势. 记述了由特定底物的生物转化合成香精香料. 讨论一些商业化工艺.     

生物分子的分离与检测

21世纪是生命科学的世纪,生命科学的发展离不开研究手段(主要是分离、分析、测试手段)的创新和发展。而分析方法的发展也推动了生命科学的研究向更高、更深入的层次进展。分析生物化学(ana lyticalbiochemistry)在这种背景下应运而生,它是利用现代的分析、分离手段来获取生物体系中的有关化学信息以及各种相互作用间联系的一门新兴学科。“21世纪生命科学的特点将首先是分析与综合的统一,分析将密切地与功能研究相结合,而综合将越来越多地建立在分析的基础上。”“虽然过去存在对分析工作的生物学意义重视不够的问题,但这一情况正在迅速…     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.