Analytical methodologies for the determination of nitroimidazole residues in biological and environmental liquid samples: A review

Nitroimidazoles (NDZs) are antiprotozoal drugs that are typically used in veterinary and human medicine. NDZs and their metabolites are believed to possess genotoxic, carcinogenic and mutagenic properties, and this is (one reason) why their use has been banned within the European Union. Hence, the determination of trace residues of these substances in edible animal tissues has been of growing concern over the past few years. Even, though there has been a need to develop sensitive and reliable analytical methods to study the residues of these compounds in different matrices, available methodologies in environmental samples are rather limited. These and other pharmaceutical compounds have become one of the most important new classes of environmental pollutants that have been detected in wastewater-treatment-plant (WWTP) effluents, receiving waters, drinking water and groundwater. A compilation of the most representative analytical methodologies for the determination of NDZ residues during the last decade is presented in this paper. Its scope is the two main areas which require their determination, namely biological and environmental matrices. A detailed explanation of both areas, including sample treatment and detection systems, and future trends is presented, focusing on the difficulties of confirming analytes at low concentration levels.     

Metal complexes in medicinal chemistry: new vistas and challenges in drug design

An overview is presented of selected metal-based pharmaceuticals, either diagnostic or therapeutic, with emphasis on specific attributes and in vivo interactions of these compounds relevant to their use in medicinal applications. Both the advantages and the challenges of this approach are outlined, with possibilities for future developments accentuated.     

Comparative analysis of volatile compounds of ‘fino’ sherry wine by rotatory and continuous liquid-liquid extraction and solid-phase microextraction in conjunction with gas chromatography-mass spectrometry

Different headspace solid-phase microextraction (HS-SPME) methods have been selected and applied to the analysis of volatile compounds in ‘fino’ sherry wine by gas chromatography-mass spectrometry. A method based on rotary and continuous liquid-liquid extraction (LLE) for analysis of these same compounds has been optimised. The best conditions to extract this type of compounds using SPME and LLE were determined and both methods were validated. Both methodologies show adequate detection and quantitation limits, and linear ranges for correctly analysing these compounds. The recoveries obtained were close to 100%, with good repeatability values. The analytical and procedural advantages and disadvantages of these two methods have been compared. In general, SPME presented higher sensitivities. Both analytical methods were used to analyse five samples of ‘fino’ sherry wine supplied by different producers. No significant differences were found between the techniques at a significance level of 5%. The regression coefficients (r²) for analysis using LLE and SPME exceeded 0.94 for all compounds. The LLE procedure is a method with high repeatability and has the possibility of simultaneous extraction of several samples (up to 12), however the SPME technique is a solvent-free method presenting major advantages, such as small sample volume and higher sensitivity and simplicity.     

Optical probes for detection and quantification of neutrophils’ oxidative burst. A review

Neutrophils, also known as polymorphonuclear leukocytes (PMN), are the most common type of white blood cells, comprising about 50-70% of all white blood cells. In the event of inflammatory processes, neutrophils display increased mobility, tissue influx ability, prolonged life span, and an increased phagocytic capacity, constituting the initial participants in the cellular defense of the organism. One of the most important defense systems of neutrophils corresponds to their ability to mediate a strong oxidative burst through the formation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). While oxidative burst is important for the elimination of invading microorganisms, the overproduction of ROS and RNS or the impairment of endogenous antioxidant defenses may result to detrimental effects to the host. The nature and the extent of ROS and RNS production by neutrophils in response to different stimuli is, consequently, a matter of extensive research, with scientific reports showing an enormous variability on the detection methodologies employed. This review attempts to provide a critical assessment of the most common approaches to identify and quantify reactive species formed during the neutrophils’ oxidative burst. The detection mechanisms and performance, as well as advantages and limitations of the different methodologies, are scrutinized, focusing on the use of fluorimetric, chemiluminometric and colorimetric probes.     

Radiation-based security

The problems presented in different security areas are varied but the solutions that have been offered are generally based upon the same principles. Employing radiation to locate and identify explosives or contraband has been most obvious at airports but other locations are now receiving equal attention. Neutron and X-ray interrogation are the systems most frequently employed. However, the more recently developed approaches such as multi-view dual-energy imaging and the use of high-speed diffraction measurements are the most likely systems to become widely available. This review looks briefly at the neutron and X-ray based systems that have been developed indicating their mode of operation and their advantages and disadvantages. It then summarizes the current state-of-the-art. The paper finishes by looking in some detail at one of the most promising areas of development—in-line diffraction measurements.     

Efficient exosome extraction through the conjugation of superparamagnetic iron oxide nanoparticles for the targeted delivery in rat brain

Exosomes possess endogenous attributes and distinct biological functions, and thereby, their uses as drug nanocarriers have attracted increasing attention for biomedical practices. However, to achieve targeted therapeutic purposes, complicated extractions, as well as modifications of exosomes, are involved. Here, based on the use of superparamagnetic iron oxide nanoparticles conjugated exosome (Ex-SPIONs), a facile exosome extraction through magnetism was established. The produced Ex-SPIONs exhibited a uniform size distribution and desirable biocompatibility. Moreover, taking advantage of the magnetic properties of SPIONs, the targeted delivery of Ex-SPIONs was demonstrated in the rat brain. Therefore, the constructed SPIONs functionalized exosome shows promising therapeutic potentials, including the treatment of brain diseases.     

A novel approach for characterizing protein ligand complexes: molecular basis for specificity of small-molecule Bcl-2 inhibitors

The increasing diversity of small molecule libraries has been an important source for the development of new drugs and, more recently, for unraveling the mechanisms of cellular events-a process termed chemical genetics.(1) Unfortunately, the majority of currently available compounds are mechanism-based enzyme inhibitors, whereas most of cellular activity regulation proceeds on the level of protein-protein interactions. Hence, the development of small molecule inhibitors of protein-protein interactions is important. When screening compound libraries, low-micromolar inhibitors of protein interactions can be routinely found. The enhancement of affinities and rationalization of the binding mechanism require structural information about the protein-ligand complexes. Crystallization of low-affinity complexes is difficult, and their NMR analysis suffers from exchange broadening, which limits the number of obtainable intermolecular constraints. Here we present a novel method of ligand validation and optimization, which is based on the combination of structural and computational approaches. We successfully used this method to analyze the basis for structure-activity relationships of previously selected (2) small molecule inhibitors of the antiapoptotic protein Bcl-xL and identified new members of this inhibitor family.     

枪弹射击残留物检验方法

射击残留物作为涉枪案件的重要物证,是法庭科学领域的重要研究对象.射击残留物主要源于未燃烧或者部分燃烧的发射药、底火等,主要残留于射击者、枪支及被射客体上.随着各类分析检验方法的发展,针对射击残留物中的有机成分和无机成分,射击残留物的检验方法也从简单的化学检验发展到更加准确的仪器分析.     

Analysis of glycerophospho‐ and sphingolipids by CE

Glycerophospholipids are amphiphilic molecules possessing polar head groups with a glycerol backbone and nonpolar variable long‐chain fatty acids. Numerous molecular species are found in a single class of glycerophospholipid, conferring to these lipids a high structural diversity. They are major components of biological membranes and participate in important activities involving cell signaling and substrate transport. Sphingolipids consist of long‐chain bases linked by an amide bond to a fatty acid and via the terminal hydroxyl group to complex carbohydrate or phosphorus moieties, constituting a complex family of compounds that also present an enormous structural variability. As important component of neuronal membranes, sphingolipids contribute to cellular diversity and functions and are associated with several neurodegenerative disorders. Moreover, they were studied in several foods due to their sensorial, reological, and antioxidant characteristics. In this work, the most relevant information available on glycerophospholipid and sphingolipid analysis by CE is reviewed. CE is a very promising analytical technique in polar lipid analysis, which provides high efficiency, relatively high resolution, and enormous versatility and requires small amounts of sample and solvent. MEKC and NACE methodologies have been developed as the most useful alternatives for these analyses by CE. Very interesting LODs have been achieved enabling the application of CE to the determination of glycerophospholipids and sphingolipids in several food and biological matrices.     

基于结构的组合库设计策略在新药创制中的应用

合理设计一些容量小的、针对特定靶标的化合物库(称为集中库,focused library),是当前组合库设计中的热点。当靶标的三维结构可以通过X射线衍射或NMR等手段确定后,人们就能采用几种不同的策略来进行组合库的设计。本文讨论了在靶标结合位点的约束下,进行组合库设计的主要方法及程序,同时强调了它们的优点与不足。通过这些方法的成功应用实例,显示了它们在新药创制中的广泛应用前景。     

Biosensors in forensic analysis. A review

Forensic analysis is an important branch of modern Analytical Chemistry with many legal and socially relevant implications. Biosensors can play an important role as efficient tools in this field considering their well known advantages of sensitivity, selectivity, easy functioning, affordability and capability of miniaturization and automation. This article reviews the latest advances in the use of biosensors for forensic analysis. The different methodologies for the transduction of the produced biological events are considered and the applications to forensic toxicological analysis, classified by the nature of the target analytes, as well as those related with chemical and biological weapons critically commented. The article provides several Tables where the more relevant analytical characteristics of the selected reported methods are gathered.     

Theoretical evaluation of sensitivity and thermal stability for high explosives based on quantum chemistry methods: A brief review

Over the past 20 years, a number of scientists have conducted numerous fundamental investigations based on quantum chemistry theory into various mechanistic processes that seems to contribute to the sensitivity of energetic materials. A large number of theoretical methods that have been used to predict their mechanical and spark sensitivity are summarized in this article, in which the advantages and disadvantages of these methods, together with their scope of use are clarified. In addition, the theoretical models for thermal stability of explosives are briefly introduced as a supplement. It has been concluded that the current ability to predict sensitivity is merely based on a series of empirical rules, such as simple oxygen balance, molecular properties, and the ratios of C and H to oxygen for different classes of explosive compounds. These are valid only for organic classes of explosives, though some special models have been proposed for inorganic explosives, such as azides. An exact standard for sensitivity should be established experimentally by some new techniques for both energetic compounds and their mixtures. © 2013 Wiley Periodicals, Inc.     

Dissecting exosome inhibitors: therapeutic insights into small-molecule chemicals against cancer

Intensive research in the field of cancer biology has revealed unique methods of communication between cells through extracellular vesicles called exosomes. Exosomes are released from a broad spectrum of cell types and serve as functional mediators under physiological or pathological conditions. Hence, blocking the release of exosome bio carriers may prove useful for slowing the progression of certain types of cancers. Therefore, efforts are being made to develop exosome inhibitors to be used both as research tools and as therapies in clinical trials. Thus, studies on exosomes may lead to a breakthrough in cancer research, for which new clinical targets for different types of cancers are urgently needed. In this review, we briefly outline exosome inhibitors and discuss their modes of action and potential for use as therapeutic tools for cancer.Subject terms: Cell biology, Cancer, Biologics     

Photo and electroluminescence of lanthanide(III) complexes

Major classes of coordination compounds used as electroluminescent materials are surveyed, and their advantages and disadvantages are discussed. The strategy of the directed synthesis of lanthanide(III) complexes promising for use as electroluminescent materials is formulated. The results of studies dealing with the design of electroluminescent devices based on europium(III), terbium(III), and thulium(III) complexes are considered.     

Oxidative stability and phenolic content of virgin olive oil: an analytical approach by traditional and high resolution techniques

The characteristic resistance to oxidation of virgin olive oil is related to its unique fatty acid composition in addition to several minor components that have antioxidant properties. Among the latter, phenols are the most important. Several factors can influence the chemical or enzymatic oxidative processes that extend or shorten the shelf-life of olive oil. Furthermore, the amount of phenolic compounds extracted during production is fundamental for the oxidative and nutritional quality of the oil. In fact, it is well known that different steps used for preparation of virgin olive oil may determine differences in the quantities of phenol. At present, various analytical methods are available to analyze the hydrophilic components, including spectrophotometric assays (traditional) and high resolution chromatographic techniques (HRGC, HPLC, HPCE). In this review we summarize these different methodologies and demonstrate that the amount of phenolic compounds in virgin olive oil as determined by both traditional and high resolution techniques can be influenced by different factors including the olive cultivar and degree of ripeness, as well as by production and extraction technologies.     

The analysis of microbial proteomes: strategies and data exploitation

Microbes present special opportunities for proteomic analysis that are not yet available for other types of organisms, due mainly to the relative abundance of information on their genomes, their low levels of functional redundancy and their experimental tractability. They are also being used to develop and validate powerful new experimental approaches that surmount some important current limitations in this field. The review surveys the different proteomic procedures that are available and considers the advantages and disadvantages of different experimental strategies. The ways in which microbiologists - and others - can exploit proteomic data are also discussed.     

Recent synthetic methodologies for pyridopyrazines: An update

Abstract

Among heterocyclic compounds, pyridopyrazines are the scaffolds that have gained considerable attention on academic and industrial level due to their widespread applications as intermediates in the preparation of advanced and biologically potent pharmaceutical materials. Many pyridopyrazine derivatives are available in market to cure various pharmacological disorders. These candidates can be synthesized via a number of synthetic routes using various reagents like cyclocondensation of diaminopyridines with carbonyl compounds or their derivatives etc. In the present review, we have elaborated all these protocols along with different factors and reaction conditions such as use of metal catalyst, solvent-free and microwave irradiation, one-pot synthesis etc. that have resulted in high regioselectivity and yields. The review focuses on the synthetic methodologies developed in the last decade for different pyridopyrazine derivatives.     

微流控技术在外泌体分离分析中的研究进展

外泌体是一类由细胞分泌的含有脂质、蛋白、核酸等多种物质的纳米级囊泡,主要参与细胞间的物质交换及信息传导,与多种疾病的发生发展密切相关。对外泌体进行深入研究,理解其生物学功能,对疾病诊断与治疗具有重要意义。由于外泌体尺寸较小且密度和体液接近,想要对复杂生物样本中的外泌体进行分离与分析十分困难。传统的外泌体分离方法如超速离心、超滤等大都需要借助大型仪器设备,且耗时长、操作复杂。因此迫切需要开发高效、便捷的外泌体分离检测手段。微流控技术因其微型化、高通量、可集成等特点,为外泌体的分离分析提供了一个新的平台。该文主要对近年来微流控技术在外泌体分离分析相关领域的研究进展进行了综述。重点从外泌体物理特性和生化特性两个角度出发,介绍了微流控芯片技术用于外泌体分离领域的主要原理、策略和方法。此外,还介绍了微流控技术与荧光、电化学传感、表面等离子体共振等多模态检测方法结合,实现外泌体一体化分析的新进展。最后,该文分析了目前微流控技术用于外泌体分离检测存在的挑战,并对其发展趋势和前景进行了展望。随着微流控外泌体分离分析装置的不断微型化、集成化、自动化,微流控芯片技术将在外泌体分离、生化检测、机制研究等方面将发挥越来越重要的作用。     

Organic UV filters in marine environments: An update of analytical methodologies,occurrence and distribution

Ultraviolet filters (UV Filters) are compounds that are widely employed in personal care products such as sunscreens to protect the skin from sun damage, but they are also added to other products, such as food packaging, plastics, paints, textiles, detergents, etc. The continuous use of these products causes the release of a substantial amount of these products into the marine environment through direct input or wastewater discharge, and thus they are becoming an important class of contaminants of emerging concern. A correlation between their occurrence and different negative effects on marine biota has been reported.Taking into account all the possible impacts on the environment, knowledge of their presence and distribution in the different compartments of the ecosystems, ranging from waters and sediments to aquatic organisms, which potentially suffer from bioaccumulation and biomagnification processes, is essential. High concentrations of ultraviolet filters have been found in samples collected from across the entire planet, even in polar regions, revealing their global distribution.Therefore, interest in the sensitive determination of ultraviolet filters in several marine matrices has increased. In this article, an overall review of the more recently reported analytical chemistry methods for identifying and quantifying these compounds in marine environmental samples is presented. We compare and discuss the potential advantages and disadvantages of every step involved in the analytical procedure, including the pre-treatment, treatment and extraction processes that are required to avoid matrix effects. Moreover, we describe the worldwide occurrence and distribution of those most important UV filters.     

Ion chromatography for the analysis of glyphosate and its selected metabolites. A review

Among all known compounds with herbicide activity glyphosate, has been the most commercially successful one. Currently, it is under evaluation because of its possible cancerogenic properties. However, the question is—if it is possible to completely withdraw it from use. Before it can happen, it is important to be sure of all its benefits and limitations, and this requires further detailed research. Due to the extent and prevalence of its use, glyphosate ends up in the environment and then in food and our bodies. There are several methods used for their determination. One of them is ion chromatography. Taking into account its advantages and disadvantages, as well as its rapid development, their importance in this field can be expected to increase in the near future. This paper summarizes the literature data from the past 22 years. The applications of ion chromatography in the determination of glyphosate in various types of environmental, food, and other samples are described. Moreover, the methods used so far are compared with the possibilities offered by ion chromatography, which main advantages and benefits are easy availability, low operating costs, green chemistry aspects, and suitable validation parameters.