Chitosan-based nanocomposites for medical applications

Chitosan as a biobased polymer is gaining increasing attention due to its extraordinary physico-chemical characteristics and properties. While a primary use of chitosan has been in horticultural and agricultural applications for plant defense and to increase crop yield, recent research reports display various new utilizations in the field of advanced biomedical devices, targeted drug delivery, and as bioimaging sensors. Chitosan possesses multiple characteristics such as antimicrobial properties, stimuli-responsiveness, tunable mechanical strength, biocompatibility, biodegradability, and water-solubility. Further, chitosan can be processed into nanoparticles, nano-vehicles, nanocapsules, scaffolds, fiber meshes, and 3D printed scaffolds for a variety of applications. In recent times, nanoparticles incorporated in chitosan matrices have been identified to show superior biological activity, as cells tend to proliferate/differentiate faster when they interact with nanocomposites rather than bulk or micron size substrates/scaffolds. The present article intents to cover chitosan-based nanocomposites used for regenerative medicine, wound dressings, drug delivery, and biosensing applications.     

Caveat receptor: proteomes on display

Display methods development is currently extending the application of this strategy beyond the generation of ligand binding reagents for research, clinical, or biotechnological purposes to its use as a primary research tool. Peptide- and cDNA display methods have the potential to contribute to understanding the mechanisms of certain classes of drugs and to help map protein-protein interactions of physiological importance. Although the critical contribution of comprehensive amino acid sequence databases has been recognized, of equal importance might be structural genomics concepts in the application of display system technology to proteomics research. Lessons learned from the study of antibody-antigen interactions are reviewed here and applied to the field of display technology with the goal of delineating major factors involved in the successful mimicry of natural protein-ligand interactions.     

二氧化铈与氢气之间相互作用及其在炔烃选择加氢中的应用

二氧化铈因其具有较强的氧化还原性能和多变的酸碱功能而在催化领域有着广泛的应用,其可用作催化剂、改性剂或载体.虽然二氧化铈常被用于氧化反应,但由于其独特的选择性地将炔烃加氢成烯烃的能力,近年来引起了广泛的研究兴趣.氧化铈出色的加氢能力引发了新的研究热潮,以了解纯二氧化铈用作加氢催化剂的原理.本文综述了近年来氧化铈的实验和计算研究进展,重点介绍了氧化铈与氢气的相互作用和加氢反应.讨论了各种研究的重要观点,包括原位光谱/显微镜和铈在涉氢反应中的理论模型,从而阐明了氧化铈催化炔烃加氢反应能力的本质和反应机理.最后在总结和展望部分提出了进一步提高对铈基材料加氢反应机理认识和催化性能的途径.     

Phage display for the generation of antibodies for proteome research, diagnostics and therapy

Twenty years after its development, antibody phage display using filamentous bacteriophage represents the most successful in vitro antibody selection technology. Initially, its development was encouraged by the unique possibility of directly generating recombinant human antibodies for therapy. Today, antibody phage display has been developed as a robust technology offering great potential for automation. Generation of monospecific binders provides a valuable tool for proteome research, leading to highly enhanced throughput and reduced costs. This review presents the phage display technology, application areas of antibodies in research, diagnostics and therapy and the use of antibody phage display for these applications.     

Polymer and azo-dye composite: a photo-alignment layer for liquid crystals

In this article, we disclose a method to fabricate polymer-stabilised azo-dye photo alignment layers for liquid crystal. The idea includes the introduction of polymer network in the alignment layer, in optimal concentration, followed by two-step irradiation. The stabilised photo-alignment layer has been explored for different aspects of the display-related parameters, viz. anchoring energy, stability for various display-related environments as a function of concentration of monomer and irradiation, residual DC and voltage holding ratio. The composite photo-alignment layer offers well-suited parameters for the liquid crystal alignment and therefore could find application in a variety of modern photonic and display devices.     

Recent advances in the application of sulfinic acids for the construction of sulfur-containing compounds

Sulfur-containing organic compounds display wide applications in the field of materials science, synthetic chemistry, and pharmaceutical industry. Thus, numerous synthetic strategies have been developed for the synthesis of sulfur-containing compounds in synthetic chemistry. In recent years, the utilization of sulfinic acids as versatile synthons has emerged as attractive and powerful approach to access various organosulfur compounds through sulfonylation, sulfinylation or sulfenylation reaction...     

Polydiacetylenes: supramolecular smart materials with a structural hierarchy for sensing, imaging and display applications

While a large variety of conjugated polymers exist, polydiacetylenes (PDAs) remain a major research area among scientists due to their interesting optical, spectral, electronic, and structural properties. Heavily reviewed in regards to their stimuli responsive properties, much is known about the assortment of sensing and detection capabilities of PDAs. In this article, we look more upon the structural diversities of polydiacetylenes that have been achieved in recent years, particularly from a hierarchical perspective of 1, 2, and 3-dimensional configurations. In addition, we examine how these different dimensional arrangements of PDAs have heralded clear applications in several key areas. Successful integration of these stimuli-responsive "smart" materials into various geometries has required researchers to have a comprehensive understanding of both the fabrication and synthesis processes, as well as the signalling mechanism for the optical, fluorogenic or spectral transitions. The on-going discovery of new PDA formulations continues to provide interesting structural manifestations such as liposomes, tubes, fibres, organic/inorganic incorporated hybrids and composite structures. By highlighting some of the recent conceptual and technological developments, we hope to provide a measure of the current pace in new PDA derivative development as core components in efficient sensor, imaging and display systems.     

Identification of Amino Acid Residues Responsible for the Binding to Anti-FLAG™ M2 Antibody Using a Phage Display Combinatorial Peptide Library

FLAG, a short hydrophilic peptide consisting of eight amino acids (DYKDDDDK), has been widely used as a fusion tag for the purification and detection of a wide variety of recombinant proteins. One of the monoclonal antibodies against this peptide, anti-FLAG M2, recognises a FLAG peptide sequence at the N terminus, Met-N terminus, C terminus, or internal site of a fusion protein and has been extremely useful for the detection, identification, and purification of recombinant proteins. Nevertheless, detailed binding specificity of anti-FLAG M2 has yet to be determined. In the current study, a phage display combinatorial peptide library was used to determine that the motif DYKxxD encompasses the critical amino acid residues responsible for the binding of FLAG peptide to this antibody. This study demonstrates the utility of phage display technology and helps to elucidate the mode of action of this detection system.     

New developments in the dye-doped polymer dispersed liquid crystals gratings: A review

In this study, the dye-doped polymer dispersed liquid crystals (PDLC) gratings techniques performed by the various research groups or being developed are briefly reviewed. Especially, the electrically switched diffraction and holographic gratings, have attained much attention by various research groups working in the PDLC-related display studies. The fabrication methodologies used for such grating texture, include like the conventional dye-doped PDLC grating, Azo-dye doped PDLC gratings, and lasing techniques etc., adopted for dye-doped PDLC gratings. The useful features and characteristics of their fabrication process of such gratings are discussed. Finally, some of the future perspectives on this particular research field are presented.     

Geographic characterization of Greek wine by inductively coupled plasma–mass spectrometry macroelemental analysis

Abstract

Studying wine mineral profile has been proven as a valuable tool in geographical origin discrimination and authenticity for both producers and consumers. Adulteration of wines, in terms of geographical origin or variety, is considered a major topic of extensive research. Traceability and authenticity of wines have been previously studied on the basis of typical mineral element patterns by means of chemometric methods. In this context, analytical methods were developed for the determination of mineral elements in wines by inductively coupled plasma–mass spectrometry. This study aimed at classifying selected varietal Greek wines from various regions by employing instrumental analysis. Preliminary data of wine mineral content enabled for the classification of samples according to geographical origin and variety. However, further work is required in order to draw more valid conclusions and to obtain a detailed map of the mineral element content of Greek wines according to their geographical origin and/or variety.     

Recent advances in synthesis of ketenimines

Ketenimines are a kind of reactive species that can be used as synthetic intermediates. In the last two decades, there has been a surge of interest in this class of building blocks and their applications, which has led to extensive research on ketenimine derivatives such as fluorine ketenimine, metal complexes of ketenimines, and the various methods of their preparation. Ketenimines have been prepared by a variety of methods, including photolysis, elimination, or rearrangement reactions. As well as, ketenimines can be prepared using a variety of useful reagents, including isocyanates, copper acetylide, amides, organometallic compounds, and metal complexes. An overview of these achievements is presented here.     

MSDCARB — a database and software for mass spectral data of carbohydrates

A special database has been developed for the mass spectral data of carbohydrates and their conjugates (MSDCARB), together with appropriate software which allows one to collect, store, edit, retrieve, search, compare and display mass spectra in table form or in graphic mode. The database contains over 400 electron impact 70 eV and/or 12 eV low resolution mass spectra obtained at the Institute of Chemistry of the Slovak Academy of Sciences. The database can be extended using re-evaluated mass spectral data from other sources. The software described enables the handling of mass spectral data libraries, the creation of sub-libraries, browsing through the libraries according to various criteria and their combination and the comparison of spectra using a variety of parameters.     

黄烷酮化合物的合成研究进展

黄烷酮化合物是自然界中广泛存在的一类具诸多生理活性的重要化合物，本文对近20年来黄烷酮化合物的合成研究进展进行了综述。     

Proteomics and Its Application in Biomarker Discovery and Drug Development

Proteomics is a research field aiming to characterize molecular and cellular dynamics in protein expression and function on a global level. The introduction of proteomics has been greatly broadening our view and accelerating our path in various medical researches. The most significant advantage of proteomics is its ability to examine a whole proteome or sub-proteome in a single experiment so that the protein alterations corresponding to a pathological or biochemical condition at a given time c…     

纳米铁及铁基纳米复合粒子在环境修复中的研究进展

由于纳米零价铁及铁基纳米复合粒子对大多数常见的环境污染物,如重金属离子、卤代有机物等均具有转化和降低毒性的作用,因此,在环境修复领域,它们已成为研究的热点之一。 纳米零价铁及铁基纳米复合粒子的比表面积大,反应活性高,应用灵活,为大多数具有挑战性的环境污染问题提供了一个有效的解决方法。 本文主要阐述了近些年来纳米零价铁及铁基纳米复合粒子在环境修复中的具体应用,同时也评估了其对环境微生物的潜在毒理效应,为以后进一步研究工作奠定一定的理论基础。     

微流控芯片技术在生殖研究中的进展

生殖是生物体最基本特征之一，是物种得以延续和进化的保证。近年来，微流控芯片系统得到了迅猛发展，技术也逐渐成熟，具有良好的应用前景。在生殖研究中，微流控技术具有以下优势：微管道的形状和尺寸可以灵活设计，从而更好地模拟生理环境；微流控芯片对样品的消耗量低；微流控技术具有很高的集成性。微流控技术已被应用到精子活力评价与筛选、精子的化学趋向性筛选、卵丘细胞去除、透明带移除、卵细胞定位与筛选、受精过程、早期胚胎培养以及生殖器官模拟等各个方面。该文着重介绍近几年基于微流控技术生殖研究的最新进展，并对其应用前景进行展望。     

The (α-4) photoconjugates of 5-methylcytosine, 1,5-dimethylcytosine, 1-methylthymine and thymidine

The pyrimidine nucleobases contained in DNA undergo a variety of photoinduced reactions in which two moieties become joined to form a product (e.g. formation of cyclobutane dimers and [6-4] adducts). Herein, we describe a new type of photoconjugation reaction that has been shown to occur for 5-methylcytosine (5-MeC), 1,5-dimethylcytosine (1,5-diMeC), 1-methylthymine and thymidine; in this reaction the 5-methyl group of one nucleobase (or nucleoside) becomes attached to the 4-position of the second moiety. For example, 5-MeC forms α-4'-(5'-methylpyrimidin-2'-one)-5-methylcytosine. The various (α-4) conjugates are produced upon irradiation of the parent compound in frozen aqueous solution at -78.5°C. The UV spectra of these compounds display a characteristic "double humped" profile, similar to that expected from overlaying the spectrum of parent nucleobase with that of a 2'-pyrimidone moiety. Preliminary results suggest that thymine and 5-methyl-2'-deoxycytidine (5-MedCyd) form analogous photoproducts. A variety of other previously unreported photoproducts are described as well for the 5-MeC, 1,5-diMeC and 5-MedCyd systems.     

基于键价理论的晶体及表面结构分析软件

用Visual C＋＋语言设计制作了分析晶体及其表面的BVStr软件.它的最大特点在于以Pauling键价理论为基础，并适用于PC机的Windows操作系统.软件在重点对晶体体相的（包括配位）结构和表面结构进行计算的同时，还计算了它们的键价数据.另外软件还配有二维和三维结构演示功能以及某些结构计算小工具.因此本软件不仅适合于研究体相及表相结构的稳定性及其演化，同时也可以用于教学.     

Recent Developments in Chitosan-Based Micro/Nanofibers for Sustainable Food Packaging,Smart Textiles,Cosmeceuticals, and Biomedical Applications

Chitosan has many useful intrinsic properties (e.g., non-toxicity, antibacterial properties, and biodegradability) and can be processed into high-surface-area nanofiber constructs for a broad range of sustainable research and commercial applications. These nanofibers can be further functionalized with bioactive agents. In the food industry, for example, edible films can be formed from chitosan-based composite fibers filled with nanoparticles, exhibiting excellent antioxidant and antimicrobial properties for a variety of products. Processing ‘pure’ chitosan into nanofibers can be challenging due to its cationic nature and high crystallinity; therefore, chitosan is often modified or blended with other materials to improve its processability and tailor its performance to specific needs. Chitosan can be blended with a variety of natural and synthetic polymers and processed into fibers while maintaining many of its intrinsic properties that are important for textile, cosmeceutical, and biomedical applications. The abundance of amine groups in the chemical structure of chitosan allows for facile modification (e.g., into soluble derivatives) and the binding of negatively charged domains. In particular, high-surface-area chitosan nanofibers are effective in binding negatively charged biomolecules. Recent developments of chitosan-based nanofibers with biological activities for various applications in biomedical, food packaging, and textiles are discussed herein.     

埃洛石纳米管的应用研究现状

埃洛石纳米管是一种新型的纳米材料,价廉易得且具有优异的性能,目前对它的研究是国际材料领域的前沿和热点,与碳纳米管相比它具有独特的结构特点和明显的资源优势。本篇综述回顾了埃洛石纳米管的应用研究进展,扼要介绍了埃洛石纳米管的化学组成及晶体结构。埃洛石纳米管的功能与其结构特点息息相关,文章以它对水、甲醇、乙醇等氢键流体的输运性能、对燃料气体的储存容纳、对药物大分子微胶囊包裹以及作为治理环境吸附剂等为例,浅谈它在物质吸附、储存、输运方面的应用;以它作为重油催化裂化的催化剂和酶及金属氧化物的催化剂载体为例,浅谈在催化方面的应用。最后,对高岭土资源的有效开发利用以及埃洛石纳米管应用研究领域的未来方向提出了一些设想。