The determination and role of peroxyacetil nitrate in photochemical processes in atmosphere

Peroxyacetilnitrates (PAN) is the most characteristic photoxidant of a range of secondary pollutants formed by the photochemical reaction of hydrocarbons with nitrogen oxides in the atmosphere: it is phytotoxic and shows an increasing role in human health effects due to ambient air exposure, especially in presence of high ozone concentrations. Because of the similarity of the conditions required for their photochemical production PAN is observed in conjunction with elevated ozone concentrations. PAN has very low natural background concentrations so it is the very specific indicator of anthropogenic photochemical air pollution. In this paper we report PAN concentrations determined in Rome urban area during winter- and summer-period. PAN measurements were carried out by means of a gas-chromatograph equipped with an Electron Capture Detector (ECD) detector. For identifying the acute episodes of atmospheric photochemical pollutants the relationship between PAN and the variable Ox (=NO2+O3) which describes the oxidation process evolution is investigated. The role of Volatile Organic Compounds and PAN in the ozone formation is investigated as well the issue of taking in account the autovehicular emissions for checking the NOx fraction in fuel.     

Regulation of the biological properties of medical polymer materials with the use of a gas-discharge plasma and vacuum ultraviolet radiation

The mechanisms of the interaction of a gas-discharge plasma and vacuum ultraviolet (VUV) radiation with medical polymers were considered. Various techniques were proposed for the use of plasma-chemical and photochemical processes for enhancing the biocompatibility of medical polymers. The plasma-chemical and photochemical processes for the surface functionalization and regulation of the biological characteristics of medical polymers by the immobilization of proteins, biologically active compounds, and liquid-crystal biosensors were described. The relationships of the surface processes that occur in the VUV photolysis of polymers with the kinetics of protein adsorption and the adhesion of blood cell components were analyzed.     

A lab-on-disc centrifugal microfluidic system for ultraprecise plasma separation

As the medical community puts forward higher requirements for the speed and convenience of disease diagnosis, point-of-care testing has become a hot research topic to overcome various kinds of healthcare problems. Blood test is considered to be highly sensitive and accurate in clinical diagnosis. However, conventional plasma separation system tends to be bulky and needs professional operations. Moreover, imprecise separation may cause residual biochemical substances such as blood cells to affect the detection results. In this work, to solve these problems, we designed a portable centrifugal microfluidic platform for automatic, rapid and ultraprecise blood separation. The disc consists of multichambers and multi-microchannels where a plasma reservoir and a cell reservoir are connected to each other and collinear with the center of the circle. This structure overcomes the weakness of low separation efficiency (when hematocrit increases) under the traditional blood separation structure (bifurcation structure). As a result, the proposed system achieved 99.9% plasma purity, 99.9% separation efficiency (with a blood hematocrit of 48%) and 32.5% plasma recovery rate in the 50s, which provides a strong guarantee for rapid blood diagnosis and analysis, especially in areas where medical resources are limited.     

Quality of Fish-Oil-Based Dietary Supplements Available on the Italian Market: A Preliminary Study

The global market of food supplements is growing rapidly with a large turnover. Fish oil supplements represent a significant part of this turnover as they are believed to have important health benefits. Conversely, there are few papers in the literature about the quality control of fish oil capsules. As prior studies illustrate, a perfect agreement with the label is rarely found, and in some isolated cases, large amounts of soybean oil are also detected, indicating a true adulteration rather than a non-compliance with the label. None of the available studies refer to the Italian market, which ranks first in Europe in the consumption of food supplements. In this present communication, a quality control of fish-oil-based supplements from the Italian market was carried out for the first time. With minor deviations, all results showed substantial agreement with the label. However, the most important conclusion from this research is that compliance with the label is not enough to judge a product of good quality. The analysis of the overall fatty acid composition showed that some supplements have a high level of saturated fatty acids, and therefore they did not undergo a proper purification process. This may represent a safety issue since the purification process also allows the removal of toxic contaminants.     

精细化学品复配技术应当受到化工人的高度重视——开设精细化学品配方设计课程之思索

精细化学品已成为当今世界化工市场的竞争热点,对从事新产品开发的化工职业人来说,其复配技术更是体现其技能水平的标尺之一。面向21世纪的化学化工专业学生开设精细化学品配方设计课程具有深刻的职业技能培训和工程化教育意义。本文简介了由作者编著、化学工业出版社出版的同名高等学校教材,推介了该课程教学过程中实施的新颖考查形式和要求。     

Photoinduced proton-coupled electron transfers in biorelevant phenolic systems

Proton-coupled electron transfer (PCET) reactions have received much attention over the past 10 years, from an experimental as well as from a theoretical point of view. At the heart of many chemical and biological processes, such reactions are of particular interest in energy conversion and enzymatic processes. Among the numerous examples of PCET reactions, photosynthesis and particularly reactions inside the Photosystem II (PSII) subunit, involving a global four electrons and four protons process to perform water oxidation and respiration, is the most emblematic one. This review focuses on the photochemical approaches of PCET reactions involving phenolic molecules. Indeed, a significant part of photochemical PCET studies were conducted on tyrosine or phenol relevant to PSII and charge transport in enzymes. The mechanisms of these reactions, sequential or concerted, with particular emphasis on the influence of pH, temperature, solvent nature and H-bonding pattern are presented based on photochemical techniques and related theoretical analysis.     

有机小分子纳米粒子的光学诊疗应用

癌症严重威胁着人类健康, 因此, 急需开发高效的诊断和治疗方法. 基于光敏剂和近红外激光的光学诊疗将诊断和治疗集于一体, 与传统的手术治疗和化学治疗相比, 光学诊疗显示出无创性和高空间选择性的优点. 有机小分子染料具有确定且易于修饰的化学结构、 良好的重现性和优异的生物相容性, 与无机和聚合物材料相比, 它是一类具有前景的可用于光学诊疗的光敏剂. 本文总结了基于传统小分子染料、 给体-受体(D-A)共轭小分子和聚集诱导发光(AIE)分子等有机小分子的纳米粒子在光学诊疗中的应用. 此外, 对于光学诊疗用有机小分子染料纳米粒子未来的挑战和前景也进行了展望.     

Sulfur aromatic heterocycles: A new kind of solar ultraviolet-B radiation actinometers

Indoline-2-thione (BC) and benzimidazole-2-thione (BN) are two aromatic compounds containing a NCS synthonic unit in a heterocyclic ring of five centres, where the main electronic absorption bands are localized in the spectral range of the ultraviolet A and B.After ultraviolet irradiation by artificial sources or sunlight, these molecular systems in aqueous solution, under controlled pH, present a simple pattern of photochemical reactions defined by a typical isosbestic point in the electronic absorption spectra. The photolysis process observed follows a good linear behavior as function of the irradiation time, being a particular actinometer of short time exposition.On the other hand, the final photochemical products of indoline-2-thione and benzimidazole-2-thione, after irradiation, were identified as indole and benzimidazole, respectively. Other properties such as molecular stability in acid solution at pH < 2, photochemical conversion in a linear response in the time range from minutes to hours, and photochemical quantum yields are reported.Due to the use of water as solvent, without a health hazard by direct manipulation, from an environmental point of view we propose these two thione compounds as new potential photochemical actinometers of solar ultraviolet-B radiation.     

Exploration of novel predictive markers in rat plasma of the early stages of chronic renal failure

To identify blood markers for early stages of chronic kidney disease (CKD), blood samples were collected from rats with adenine-induced CKD over 28 days. Plasma samples were subjected to metabolomic profiling by liquid chromatography-mass spectrometry, followed by multivariate analyses. In addition to already-identified uremic toxins, we found that plasma concentrations of N6-succinyl adenosine, lysophosphatidylethanolamine 20:4, and glycocholic acid were altered, and that these changes during early CKD were more sensitive markers than creatinine concentration, a universal indicator of renal dysfunction. Moreover, the increase in plasma indoxyl sulfate concentration occurred earlier than increases in phenyl sulfate and p-cresol sulfate. These novel metabolites may serve as biomarkers in identifying early stage CKD.     

基于Kirsch算子图像分割的FPGA设计与实现

医学影像是医疗诊断的重要手段。在一些疾病的早期诊断过程中，组织的边缘信息代表重要的特征数据，对疾病的确诊起着至关重要的作用。因此对医学影像进行准确清晰的图像分割对医疗诊断的准确性具有重要的促进作用。本文采用Kirsch算子对医学影像进行图像分割获得组织边缘。为了提高运算速度和分割效率，采用具有并行运算能力的FPGA器件进行设计实现。最后在QuartusⅡ平台上进行了仿真验证，得到了精确的图像边缘。     

Exploring the photophysical behaviour of supramolecular systems: problems and perspectives

The study of the photophysical properties of supramolecular systems, such as photochemical molecular devices (PMD), is intrinsically related to the possibility of correctly describing ground and excited state properties of large systems containing transition metal atoms.Here we analyse the performance of density functional theory (DFT) and time dependent DFT in the evaluation of the photochemical behaviour of supramolecular systems aimed to produce photoinduced long-lived charge-separated states. Such PMDs are of great experimental interest as functional models for many chemical applications as, for instance, artificial photosynthesis. From a theoretical point of view, the challenge of these systems is not simply related to their size but also to the possibility of describing the “ emergence” of new properties, involving the molecule as a global unit, using the tools provided by quantum chemistry.     

Understanding the quality concept in health care

During the past three decades there has been an intense debate on the quality of health care. Errors in medicine, practice variations, competence of physicians, scarcity and lack of resources have all been reasons for discussing the quality of care. A clear definition of quality should explain the nature of the debate, improve uniformity of speech and facilitate meaningful actions such as quality assurance or quality improvement. However, in due course many different definitions have been proposed and principles of quality assurance in health care have been frequently questioned, because of their industrial nature. It raises questions on our understanding of quality in health care. In this paper, we (i) explore the nature of the quality concept, (ii) explain its meaning by Wittgenstein's theory on rule-following, and (iii) argue for understanding medical care as a reflexive practice, in order to integrate the meaning of quality in medical care.     

Inactivation of lymphocytes in blood products using riboflavin photochemical treatment with visible light

Abstract Immunocompetent lymphocytes present in blood products are an important cause of immune reactions following blood transfusion such as transfusion-associated graft-versus-host disease (TA-GVHD). In this study the effects of riboflavin photochemical treatment (RPT) on lymphocyte proliferation and cytokine production in vitro were measured to establish whether RPT of blood products can be used to prevent immune reactions resulting from transfused lymphocytes. Lymphocytes and riboflavin were added together in medical PVC transparent bags and then exposed to visible light. Control lymphocytes were exposed to light in the absence of riboflavin. Lymphocytes exposed to riboflavin photochemical treatment (RPT-lymphocytes) and control lymphocytes were tested for the proliferative ability and the production of several cytokines upon stimulation with antigens. Upon stimulation by phytohemagglutinin (PHA) the proliferation of RPT-lymphocytes was inhibited. Using flow cytometry it was shown that RPT-lymphocytes were unable to enter the S-phase of the cell cycle following PHA stimulation. The level of cytokines present in the supernatant of RPT-lymphocytes after stimulation by antigens was significantly lower than those present in the corresponding supernatant of control lymphocytes. RPT with visible light inactivates lymphocytes, inhibits lymphocyte proliferation and the production of cytokines. It appears to be a promising method to prevent immune reactions such as TA-GVHD.     

Quality planning in the ’in vitro diagnostic’ industry

In vitro diagnostic (IVD) manufacturers play an important role in helping to provide laboratory results that meet the needs of patient care. Industry, the primary source of new technologies, uses established processes to assure a continuous supply of products that satisfies health care needs. The processes include validation of user needs, with well-controlled procedures that are used to manufacture quality products. Management uses routine audits and customer complaint monitoring to identify improvement opportunities. The processes used in the IVD industry are recognized quality practices that should be, and often are, used in the clinical laboratory.     

A prelude of the 2004 Antwerp Quality Conference: Targets and target values—integrating quality management and costing

Questions about the value of services in the health care sector and the quality of them have been addressed frequently during the last decade, but as separate issues. In this article a method is proposed to combine these two issues. The starting point is the observation that competition will become fiercer among providers in the health care sector . Moreover, the patients opinion about quality in terms of convenience, emotional attention, etc., will be important in a competitive environment and will determine which health care service providers will be successful. These developments will have an impact on the engineering of the health care chain. Methods are discussed to integrate the determination of the value of innovations and new products, and the design of quality systems. The system of target costing is focused upon. It takes the outcome of care processes as desired by customers or the users as the starting point both for pricing the services as well as for designing the delivery system. This will not only improve cost control, but also quality improvements in two ways. First, the delivery system will be better adapted (and integrated if more health care providers are involved) to the needs of the patients, and second quality will improve as health care providers analyze, redesign, and monitor their processes more extensively.Presented at the 9th Conference on Quality in the Spotlight, 18–19 March 2004, Antwerp, Belgium     

Electrokinetics with blood

Microfluidics based lab‐on‐a‐chip technology holds tremendous promises towards point‐of‐care diagnosis of diseases as well as for developing engineered devices aimed towards replicating the intrinsic functionalities of human bodies as mediated by blood vessel mimicking circulatory networks. While the analysis of transport of blood including its unique cellular constituents has remained to be the focus of many reported studies, a progressive interest on understanding the interplay between electric field and blood flow dynamics has paved a new way towards further developments from scientific engineering as well as clinical viewpoint. Here, we briefly outline the interconnection between electrokinetics and blood flow through micro‐capillaries, in an effort to address several challenging propositions in a wide variety of applications encompassing biophysical transport to medical diagnostics. We first present the fundamentals of interaction of electric field with cellular components. In conjunction with the unique rheological features of blood, we show that this interaction may turn out to be compelling for the use of electric fields for transporting blood samples through microfluidic conduits. We discuss the perspectives of both direct current and alternating current electrokinetics in the context of blood flow. In addition, we provide a brief outline of the concerned theoretical developments. We also bring out the relevant biophysical perspectives and focus on applications such as blood plasma separation and separation of circulatory tumor cells. Finally, we attempt to provide a futuristic outlook and envisage the potential of combining electrokinetics with blood microcirculation towards developing futuristic biomimetic microdevices that can replicate a novel control mechanism over micro‐circulatory transport in the entire connective network of human bodies. This may effectively pave the way towards the realization of a next‐generation medical simulation device, significantly advanced from what is available under the ambit of the state of art technology in the field.     

Photochemical aging of in situ polymerized blends of polystyrene and poly[acrylonitrile-g-(ethylene-co-propylene-co-diene)-g-styrene] (AES)

The influence of photochemical aging of in situ polymerized PS/AES blends on their mechanical properties has been studied. The PS/AES blends were subjected to photochemical aging for 168 h and 720 h. Tensile properties and Izod impact resistance of aged and non-aged samples were evaluated. The mechanical properties of the PS/AES blends are influenced by the polymerization temperature and blend composition and represent a balance between the toughness of EPDM and the stiffness of SAN in the PS matrix. Even though the impact resistance and strain at break of HIPS are higher than those of the PS/AES blends, after the aging period all PS/AES blends showed higher strain at break than HIPS. PS/AES blends present higher photochemical stability than HIPS.     

Stochastic DNA Walkers in Droplets for Super‐Multiplexed Bacterial Phenotype Detection

Pathogen detection is growing in importance in the global health arena because of the high morbidity and mortality associated with bacterial blood stream infections. In this work, we present stochastic DNA walkers in droplets (SDwalker‐Drop), a one‐step, rapid, and super‐multiplex method for ultrahigh‐throughput bacterial detection. The SDwalkers, by exploiting cascade signal amplification, endow our analytical platform with fast analysis times and single‐cell analysis ability. The autonomous and multiple‐step walking behavior of the SDwalkers provides a super‐multiplex droplet‐encoding strategy by embedding intensity coded barcodes into a sequence of color‐multiplexed barcodes. We realized a theoretical coding capacity of 8³?1=511 and achieved 20 distinct patterns for bacterial phenotype detection and identification. Moreover, our SDwalker‐Drop platform could be readily integrated with a flow cytometer to afford a general approach for super‐multiplexed, high‐throughput biological assays and screening.     

A Polymer Coating Transfer Enrichment Method for Direct Mass Spectrometry Analysis of Lipids in Biofluid Samples

A porous polymer coating transfer enrichment method is developed for the direct mass spectrometry (MS) analysis of lipids. The enrichment is fast (ca. 1 min) and enables the profiling and quantitation of lipids in small‐volume biofluid samples. Coupled with a photochemical Paternò–Büchi reaction, this method enables the fast determination of lipid structure at the C=C location level and point‐of‐care lipid biomarker analysis.     

Electrochemical hematocrit determination in a direct current microfluidic device

Hematocrit (HCT) tests are widely performed to screen blood donors and to diagnose medical conditions. Current HCT test methods include conventional microhematocrit, Coulter counter, CuSO₄ specific gravity, and conductivity‐based point‐of‐care (POC) HCT devices, which can be either expensive, environmentally inadvisable, or complicated. In the present work, we introduce a new and simple microfluidic system for a POC HCT determination. HCT was determined by measuring current responses of blood under 100 V DC for 1 min in a microfluidic device containing a single microchannel with dimensions of 180 μm by 70 μm and 10 mm long. Current responses of red blood cell (RBC) suspensions in PBS or separately plasma at HCT concentrations of 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, and 70 vol% were measured to show feasibility of the microfluidic system for HCT determination. Key parameters affecting current responses included electrolysis bubbles and irreversible RBC adsorption; parameters were optimized via addition of nonionic surfactant Triton X‐100 into sample solution and carbonizing electrode surfaces. The linear trend line of current responses over a range of RBC concentrations were obtained in both PBS and plasma. This work suggested that a simple microfluidic device could be a promising platform for a new POC HCT device.