具有生物活性的有机锗化合的研究新进展

综述了近年来发展的具有各种生物活性的六类有机锗化合物的合成及生物活性，即倍半锗和介吗川类有机化合的，锗氧杂，锗氮杂及锗硫杂环酮类化合物，呋喃，噻唑，咪唑、嘧啶取代锗烷及其类似物，烷锗醇，熔锗醚和烷锗酮类化合物，卟啉锗类经合物，其它具有生物活性的有机锗化合物这六类有机锗化合物，并对该领域的研究前景作了展望。     

3-取代苯基-3-三氯锗基丙酸的合成

作者曾综述过某些有机锗化合物具有广谱药理活性,并报道了有机锗倍半氧化物,及有机锗的倍半硫化物的合成。已发表的专利证明其中一大类具有生物活性的有机锗化合物具有抗癌活性,放射增敏作用,杀菌作用,酶分解抑制作用等。而这类化合物的合成均经过3-三氯锗基丙酸中间体。本文用三氯锗烷与取代肉桂酸反应,合成了尚未见报道的新化合物,3-取代苯基-3-三氯锗基丙酸活性中间体1～14。它的合成为一系列不同种类具有生物活性的有机锗化合物的开发研究提供了重要的中间体。     

有机锗化合物的合成及其生物活性

讨论了有机锗化合物在国内外的进展。按制备方法分类,重点介绍了烃基锗化合物、螺锗及其衍生物、有机锗倍半氧化物、有机锗倍半硫化物、介吗川类有机锗化合笔挺人有生物活性的化合物。     

具有生物活性的有机锗化合物及其合成方法

具有生物活性的有机锗化合物的生物活性和合成方法的研究报道近年来逐渐增多,1977年Aldrige在国际锗、锡、铅有机金属和配位化学年会上做了题为“有机锗、锡、铅化合物的生物活性“的报告,但该文主要讨论有机锡、铅     

β—羧基—α—（取代苯基）乙基三苯基锗的合成

某些有机锗化合物具有广泛的生物活性和药理活性。人们利用有机锗的活性中间体:β-羧基乙基锗的三氯化物(简式:Cl_3GeCH_2CH_2COOH)及其衍生物进行了多方面的合成研究。有关文献报道,β-羧基-α-乙基,三烷基锗化合物具有选择性的酶分解抑制作用及较强的     

四配位有机锗化合物的红外光谱表征

对30多年所发表的四配位有机锗化合物的红外光谱进行了综合评论。即对饱和烃基锗、不饱和烃基锗、有机锗卤化合物、倍半氧锗化合物、其它这五类有机锗化合物的红外光谱作了系统的归纳，对光谱特征进行了总结。     

介吗川类化合物的新型合成

采用Ｐ２Ｏ５脱水的方法将三乙醇胺和倍半氧锗有机化合物在室温下反应得到了较高产率的介吗川类有机锗新化合物。此法特别适合制备一些含有活泼官能团的介吗川类有机锗化合物。通过元素分析、ＩＲ、＾１Ｈ ＮＭＲ和ＭＳ等分析手段验证了所合成的１４个新化合物的组成及结构。并考察了某些化合物的生物活性。     

四配位有机锗化合物的红外光谱表征

对 ３０ 多年所发表的四配位有机锗 化合物的红外光谱进行了综合 评论。即对饱和烃基 锗、不饱和 烃基锗、有机锗卤化 合物、倍半氧锗化合 物、其它这五类 有机锗化 合物的红 外光谱作 了系统的 归纳，对光谱特征进行了总结     

三苯基锗二硫代氨基甲酸酯的合成及表征

近年来 ,人们相继合成了有机锗倍半硫化物、有机锗硫杂环戊酮、含硫的螺环有机锗等化合Scheme1　 Synthetic route of compound物[1,2 ] .但烃基锗二硫代氨基甲酸酯类化合物尚未见报道 .我们 [3,4 ] 发现 ,有机锡二硫代氨基甲酸酯类化合物有很强的生物活性 .鉴于有机锗化合物比有机锡化合物毒性低得多 ,且副作用小 ,我们以三苯基氯化锗和二硫代氨基甲酸盐为原料 ,合成了一系列新型的有机锗含硫衍生物 (反应式如Scheme1所示 ) ,并对其结构进行了表征 ,初步生物活性测试结果表明 ,部分化合物显示出较强的抗癌活性 .1　实　　验1 .1　仪器与…     

新型有机锗倍半氧化物及硫化物的合成

已先后合成的倍半氧化物类及倍半硫化物类化合物的前体,即有机锗三氯化物中只含1个锗原子。为了考查从含2个锗原子的前体合成的有机锗倍半氧化物及硫化物的药物活性,我们合成了1类化合物及相应的倍半氧化物(2类)及倍半硫化物(3类),并合成了酰基苯胺化合物1_e、2_e及3_e。结果见表1。     

Environmentally Friendly Techniques and Their Comparison in the Extraction of Natural Antioxidants from Green Tea,Rosemary, Clove,and Oregano

Many current food and health trends demand the use of more ecological, sustainable, and environmentally friendly techniques for the extraction of bioactive compounds, including antioxidants. However, extraction yields and final antioxidant activities vary between sources and are highly influenced by the given extraction method and nature and ratio of the employed solvent, especially for total polyphenols, flavonoids, and anthocyanins, which are well recognized as natural antioxidants with food applications. This review focused on the most common extraction techniques and potential antioxidant activity in the food industry for various natural antioxidant sources, such as green tea, rosemary, clove, and oregano. Green extraction techniques have been proven to be far more efficient, environmentally friendly, and economical. In general, these techniques include the use of microwaves, ultrasound, high hydrostatic pressure, pulsed electric fields, enzymes, and deep eutectic solvents, among others. These extraction methods are described here, including their advantages, disadvantages, and applications.     

Synthesis,structure, and function of internally functionalized dendrimers

The past three decades have witnessed an exponential increase in the structural diversity and applications of dendrimers, spanning across drug delivery and diagnostics, protein, and enzyme mimicry, solubility enhancement, coatings, light harvesting, and catalysis. The dendrimer community has recently focused on internally functionalized dendrimers (IFDs) owing to their advanced design and functionality. The synthesis of IFDs relies on advanced orthogonal chemistries and/or (de)protection schemes, as well as careful purification to minimize polydispersity of composition and molecular weight. The studies published on IFDs, however, lay scattered across the chemical literature, and a comprehensive presentation of structural rationale, synthetic procedures, and technologically relevant applications is missing. To address this need, this review presents a comprehensive collection and discussion of all available studies on IFDs, detailing their methods of synthesis and their structure–function correlations. The wide variety of internal functionalities, including hydroxyl, amine, carboxylic acid, allyl, alkyne, and imidazole groups, enables myriad applications in biochemistry, chemical and biomedical engineering, and material science. Particular focus is given to IFDs that are amenable to modular synthetic strategies, which promote higher synthetic yield and scalability, and therefore possess stronger translational and commercial potential. As such, this review guides research groups pursuing the difficult task of IFD rational design and synthesis providing them a concise roadmap to their mission.     

Recent development in nanomaterials fabricated paper-based colorimetric and fluorescent sensors: A review

The paper-based sensing devices have drawn a broad interest in analytical chemistry for colorimetric and fluorescent-based analysis of biological, environmental, clinical, and food samples. It is due to the simple, rapid, biodegradable, user-friendly, less expensive, and low waste generation into the environment. Here, the recent development of paper-based sensors fabricated with different noble metal nanoparticles (NPs) and semiconductor and carbon quantum dots (QDs) is demonstrated to analyze several chemical substances from various samples. User-friendly and portable recording devices such as digital cameras, smartphones, scanners, etc. along with color detecting softwares are employed to measure the color intensity of nanomaterials fabricated paper devices after the deposition of a sample solution containing various chemical substances. The advantages and disadvantages of incorporating nanomaterials in the paper substrate (direct deposition, inkjet printing, screen printing and wax printing) are illustrated. The mechanism for colorimetric, fluorescence, phosphorescence, and chemiluminescence sensing using noble metal NPs (Ag, Cu, and Au), semiconductors, and carbon QDs for the determination of metal ions, anions, pesticides, biomolecules, and other toxic chemical substances are discussed. Thus, this review article would be highly useful for scientists and researchers to design colorimetric sensors to monitor chemical toxicants in clinical, environment, foods, and many other related samples.     

生物光化学

生物光化学研究光在动植物体内所引起的生化现象。例如:经过各种不同波长的光辐照后的生命现象,生长规律,某些生理和病理过程,疾病的产生和治疗机理,细胞的辐射损伤和自然防御,以及光合色素在生物进化中的作用等。本文就光引起的现象:视觉、生物钟(光周期性)、植物的光合作用、辐射损伤及其修复、牛皮癣的治疗、新生儿黄疸病的治疗机理,以及光合色素——藻胆蛋白等七种现象,做了综述性的介绍。     

三唑类药物研究新进展

三唑类化合物作为药物广泛应用于临床,是目前药物研究开发的重点领域之一．越来越多的高活性、低毒性、不良反应少、多药耐药性小、生物利用率高、药代动力学性质好、药物靶向性强、给药方式多样化、广谱、高疗效的三唑类化合物作为候选药物或药物用于临床医治多种疾病,显示出了三唑类化合物在医药领域的巨大开发价值和潜在的宽广应用．本文结合自己的工作,参考国内外近五年文献系统地综述了三唑类化合物作为药物在整个医药领域的研究与开发近况,包括抗真菌、抗细菌、抗结核、抗癌、抗病毒、抗炎镇痛、抗惊厥等,并展望其发展趋势与前景．希望该评论有助于为高活性低毒性三唑类医药合理设计提供新思路．     

THE EFFECT OF CLAY DISPERSION ON THE CRYSTALLIZATION AND MORPHOLOGY OF POLYPROPYLENE／CLAY COMPOSITES

PP/clay composites with different dispersions, namely, exfoliated dispersion, intercalated dispersion and agglomerates and particle-like dispersion, were prepared by direct melt intercalation or compounding. The effect of clay dispersion on the crystallization and morphology of PP was investigated via PLM, SAXS and DSC. Experimental results show that exfoliated clay layers are much more efficient than intercalated clay and agglomerates of clay in serving as nucleation agent due to the nano-scale dispersion of clay, resulting in a dramatic decrease in crystal size (lamellar thickness and spherulites) and an increase of crystallization temperature and crystallization rate. On the other hand, a decrease of melting temperature and crystallinity was also observed in PP/clay composites with exfoliated dispersion, due to the strong interaction between PP and clay. Compared with exfoliated clay layers, the intercalated clay layers have a less important effect on the crystallization and crystal morphology. No effect is seen for samples with agglomerates and particle-like dispersion, in regard to melting temperature, crystallization temperature, crystal thickness and crystallinity.     

Purification and properties of three cellobiases from Aspergillus niger A20

Three cellobiases, here called cellobiase A, B, and C, from the culture filtrate of Aspergillus niger A20, were purified by precipitation with ammonium sulphate, gel filtration through Sephadex G-75, and column chromatography of DEAE-cellulose. The purified enzymes were homogeneous on polyacrylamide disk electrophoresis. The mol wt of the purified enzymes were estimated by SDS-gelelectrophoresis to be 88,000, 80,000, and 71,000 for cellobiases A, B, and C, respectively. The enzymes were active at pH 4.5 and 55–60°C. The pattern of their aminoacid compositions showed high contents of aspartic acid, glutamic acid, threonine, serine, and glycine. The apparent K_m values for cellobiose were 0.9, 1.63, and 1.0 mM for cellobiases A, B, and C, respectively. Calcium ions stimulated cellobiases B and C, and Co²⁺ and Mg²⁺ ions stimulated cell obiase A. The purified enzymes hydrolyzed cellobiose and aryl-β-d-glucosides, but they had no action on sucrose, maltose, and cellulose. The three cellobiases catalyzed transglycosylate reaction, and the major product formed from cellobiose was tetramer of glucose.     

石墨烯纤维：制备、性能与应用

石墨烯纤维是一种由石墨烯片层紧密有序排列而成的一维宏观组装材料。通过合理的结构设计和可控制备,石墨烯纤维能够将石墨烯在微观尺度的优异性能有效传递至宏观尺度,展现出优异的力学、电学、热学等性能,从而应用于功能织物、传感、能源等领域。目前,石墨烯纤维主要通过湿法纺丝、限域水热组装等方法制备得到,其性能可以通过对材料体系和制备工艺的优化而进一步提升。本文首先介绍了石墨烯纤维的制备方法,然后详细阐述了石墨烯纤维的性能,讨论了其性能提升策略,并总结了石墨烯纤维的应用,最后对石墨烯纤维的未来发展、挑战和前景进行了展望。     

Tautomeric and conformational isomerism of natural hydroxyanthraquinones

Natural 1,5-di-, 1,4,5-tri-, and 1,4,5,8-tetrahydroxyanthraquinones and their anions and metal complexes were shown to be equilibrium mixtures of tautomers and conformers using quantum-chemical and correlation analysis of elecronic absorption spectra. Solvent effects, ionization, complexation, and the introduction and substitution of substituents were accompanied by shifts of tautomeric and conformational equilibria that determine the color of the compounds. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 224–229, May–June, 2006.     

纳米碳点的制备与应用研究进展

纳米碳点是碳纳米材料家族的新成员,近年来在国内外受到广泛关注。与传统的荧光染料和半导体量子点发光材料相比,碳点不仅具有优异的光学性能及尺寸效应,且具有制备成本低廉、生物相容性好、易于官能化、能带结构可调等优势。本文在理清有关碳点概念的基础之上,介绍了碳点结构特征和制备策略,着重综述了纳米碳点在生物成像与诊疗、传感器件、催化、光电器件和能量存储领域的最新研究进展,探讨了碳点研究目前存在的问题及未来的发展方向。