Asymmetric Sulfoxidation of Thioethers with Hydrogen Peroxide in Water Mediated by Platinum Chiral Catalyst

Easy stereoselective oxidation of prochiral aryl alkyl sulfides 2 to the corresponding sulfoxides can be achieved in water‐surfactant medium with inexpensive hydrogen peroxide mediated by the chiral platinum diphosphine complex {[(R)‐BINAP]Pt(μ‐OH)}₂(BF₄)₂ ( 1 ). Remarkable key features of general interest are (i) easy isolation of the products from catalyst by simple diethyl ether/water‐surfactant two phase separation, (ii) catalyst loading as low as 1% mol, (iii) good yields, sulfoxide 3 to sulfone 4 ratio up to 200 : 1 and enantioselectivities up to 88%, (iv) mild experimental conditions.     

植物油的氧化及其对淬火特性的影响

传统上,矿物油是常用淬火剂中最重要的一类淬火剂。然而,它们在本质上缺乏环保性,又有毒性,再从长期低价供应角度考虑,有必要寻找新的替代介质。石油制品油的淬火特性与其成分很有关系,因而受其氧化降解性能的限制。由于不断暴露在钢与油接触面问相对较高的温度中,石油制品油遭受热降解和氧化降解,使得其淬火特性发生明显变化。因此,淬火特性是任何一种可选择的淬火介质都必须要检验的一个非常重要的性能参数。可供选择的一类液态物质为植物油,它们具有典型的生物降解特性并且无毒。然而,植物油具有相对较差的抗氧化稳定性能,因此测定氧化对其淬火特性的潜在影响具有重要意义。本文报导的结果仅是这项巨大研究中的第一步,在这项工作中,对不受禁止的植物油的试验是在实验室设备上进行的,以前报告的促使石油制品油早期氧化的过程接近实际使用条件。依照ASTM D 6200标准,使用粘度计、红外线分光镜、^13CMR分光镜以及冷却曲线特性测定方法对所研究的液态植物油进行了性能检测并和典型的石油制品油作了成分比较。所得的结果表明,作为淬火介质,植物油是有前景的石油制品油的替代品,但在商业上要可行,同时必须使用适当的抗氧化剂。     

Biomarkers in Prostate Cancer Diagnosis: From Current Knowledge to the Role of Metabolomics and Exosomes

Early detection of prostate cancer (PC) is largely carried out using assessment of prostate-specific antigen (PSA) level; yet it cannot reliably discriminate between benign pathologies and clinically significant forms of PC. To overcome the current limitations of PSA, new urinary and serum biomarkers have been developed in recent years. Although several biomarkers have been explored in various scenarios and patient settings, to date, specific guidelines with a high level of evidence on the use of these markers are lacking. Recent advances in metabolomic, genomics, and proteomics have made new potential biomarkers available. A number of studies focused on the characterization of the specific PC metabolic phenotype using different experimental approaches has been recently reported; yet, to date, research on metabolomic application for PC has focused on a small group of metabolites that have been known to be related to the prostate gland. Exosomes are extracellular vesicles that are secreted from all mammalian cells and virtually detected in all bio-fluids, thus allowing their use as tumor biomarkers. Thanks to a general improvement of the technical equipment to analyze exosomes, we are able to obtain reliable quantitative and qualitative information useful for clinical application. Although some pilot clinical investigations have proposed potential PC biomarkers, data are still preliminary and non-conclusive.     

A facile method to compare EFTEM maps obtained from materials changing composition over time

Energy Filtered Transmission Electron Microscopy (EFTEM) is an analytical tool that has been successfully and widely employed in the last two decades for obtaining fast elemental maps in TEM mode. Several studies and efforts have been addressed to investigate limitations and advantages of such technique, as well as to improve the spatial resolution of compositional maps. Usually, EFTEM maps undergo post‐acquisition treatments by changing brightness and contrast levels, either via dedicated software or via human elaboration, in order to maximize their signal‐to‐noise ratio and render them as visible as possible. However, elemental maps forming a single set of EFTEM images are usually subjected to independent map‐by‐map image treatment. This post‐acquisition step becomes crucial when analyzing materials that change composition over time as a consequence of an external stimulus, because the map‐by‐map approach doesn't take into account how the chemical features of the imaged materials actually progress, in particular when the investigated elements exhibit very low signals. In this article, we present a facile procedure applicable to whole sets of EFTEM maps acquired on a sample that is evolving over time. The main aim is to find a common method to treat the images features, in order to make them as comparable as possible without affecting the information there contained. Microsc. Res. Tech. 78:1090–1097, 2015. © 2015 Wiley Periodicals, Inc.     

Existing large steam power plant upgraded for hydrogen production

This paper presents and discusses the results of a complete thermoeconomic analysis of an integrated power plant for co-production of electricity and hydrogen via pyrolysis and gasification processes fed by various coals and mixture of coal and biomass, applied to an existing large steam power plant (ENEL Brindisi power plant – 660 MW_e). Two different technologies for the syngas production section are considered: pyrolysis process and direct pressurized gasification. Moreover, the proximity of a hydrogen production and purification plants to an existing steam power plant favors the inter-exchange of energy streams, mainly in the form of hot water and steam, which reduces the costs of auxiliary equipment. The high quality of the hydrogen would guarantee its usability for distributed generation and for public transport. The results were obtained using WTEMP thermoeconomic software, developed by the Thermochemical Power Group of the University of Genoa, and this project has been carried out within the framework of the FISR National project “Integrated systems for hydrogen production and utilization in distributed power generation”.     

Spectral clustering with more than K eigenvectors

Spectral clustering techniques are heuristic algorithms aiming to find approximate solutions to difficult graph-cutting problems, usually NP-complete, which are useful to clustering. A fundamental working hypothesis of these techniques is that the optimal partition of K classes can be obtained from the first K eigenvectors of the graph normalized Laplacian matrix L_N if the gap between the K-th and the K+1-th eigenvalue of L_N is sufficiently large. If the gap is small a perturbation may swap the corresponding eigenvectors and the results can be very different from the optimal ones.In this paper we suggest a weaker working hypothesis: the optimal partition of K classes can be obtained from a K-dimensional subspace of the first M>K eigenvectors, where M is a parameter chosen by the user. We show that the validity of this hypothesis can be confirmed by the gap size between the K-th and the M+1-th eigenvalue of L_N. Finally we present and analyse a simple probabilistic algorithm that generalizes current spectral techniques in this extended framework. This algorithm gives results on real world graphs that are close to the state of the art by selecting correct K-dimensional subspaces of the linear span of the first M eigenvectors, robust to small changes of the eigenvalues.     

Parametric investigations of target normal sheath acceleration experiments

One of the most important challenges related to laser-driven ion acceleration research is to actively control some important ion beam features. This is a peculiar topic in the light of future possible technological applications. In the present work we make use of one theoretical model for target normal sheath acceleration in order to reproduce recent experimental parametric studies about maximum ion energy dependencies on laser parameters. The key role played by pulse energy and intensity is enlightened. Finally the effective dependence of maximum ion energy on intensity is evaluated using a combined theoretical approach, obtained by means of an analytical and a particle-in-cell numerical investigation.