Metals in Biotechnology: Cr-Driven Stereoselective Reduction of Conjugated C=C Double Bonds

Elemental metals are shown to be suitable sacrificial electron donors to drive the stereoselective reduction of conjugated C=C double bonds using Old Yellow Enzymes as catalysts. Both direct electron transfer from the metal to the enzyme as well as mediated electron transfer is feasible, although the latter excels by higher reaction rates. The general applicability of this new chemoenzymatic reduction method is demonstrated, and current limitations are outlined.     

Removal of organochlorines from vegetable oils and its benefits in preventing formation of monochloropropanediol diesters

This paper reports the first results on depleting certain organochlorines from vegetable oils without the use of any solvent in order to mitigate monochloropropanediol diesters (MCDPE). The concept is based on separating the organochlorines from the bulk oil by using trapping agents (e.g. monoacylglycerols) that can be easily separated from the oil. The process starts by mixing and homogenizing crude vegetable oils with the trapping agent and subsequently separating the trapping agent from the oil bulk via crystallization. The proof-of-concept of the approach is demonstrated on a spiked sunflower model system, solvent extracted crude sunflower oil, industrially produced crude soybean and corn oils. The depletion of organochlorines in the crude oils and its beneficial effect on the MCPDE content in the heat treated samples is measured by LC-MS. The depletion efficacy of the monitored organochlorines was estimated to be in the 60–95 % range. Both the melting point and polarity of the trapping agents affected the depletion efficacy of the organochlorines. Trapping agents with higher melting point and polarity, such as monostearin were more effective in comparison to high melting point but less polar agents such as palm stearin or agents rich in polar but low melting point monolinolein/monoolein. The effect of organochlorine depletion on the subsequent MPCDE levels in heat treated oil was in the range of 60–90 % reduction depending on the type of the studied oil.     

Prognostics of PEM fuel cell in a particle filtering framework

Proton Exchange Membrane Fuel Cells (PEMFC) suffer from a limited lifespan, which impedes their uses at a large scale. From this point of view, prognostics appears to be a promising activity since the estimation of the Remaining Useful Life (RUL) before a failure occurs allows deciding from mitigation actions at the right time when needed. Prognostics is however not a trivial task: 1) underlying degradation mechanisms cannot be easily measured and modeled, 2) health prediction must be performed with a long enough time horizon to allow reaction. The aim of this paper is to face these problems by proposing a prognostics framework that enables avoiding assumptions on the PEMFC behavior, while ensuring good accuracy on RUL estimates. Developments are based on a particle filtering approach that enables including non-observable states (degradation through) into physical models. RUL estimates are obtained by considering successive probability distributions of degrading states. The method is applied on 2 data sets, where 3 models of the voltage drop are tested to compare predictions. Results are obtained with an accuracy of 90 h around the real RUL value (for a 1000 h lifespan), clearly showing the significance of the proposed approach.     

Monte Carlo simulation of pulsed laser ablation into an ambient gas

Laser ablation from one- and two-component targets into a diluted gas background is simulated by combined direct simulation-test particle Monte Carlo method. The spatial and velocity distributions of particles deposited at the plane substrate are calculated. The approach developed has allowed us to consider the influence of the collisions both among the ablated particles and between the ablated and ambient gas particles on the uniformity of film stoichiometry. It is found that the increase of the background gas pressure results in the more uniform distribution of the stoichiometrical ratio of the deposited particles with different masses.     

舰载雷达天线载荷的确定

以三种舰载警戒雷达天线为例，对天线的风载荷、惯性载荷和自重作了分析，提出了减小天线系统风载荷的主要途径     

短纤维复合材料刚度特性的有限元随机能量法预报

本文基于能量等效原理,采用有限元法和随机统计试验的Monte-Carlo方法相结合的随机分析数值方法,提出了可用于短纤维复合材料刚度预报的有限元随机能量法.文中还以碳纤维/AG3合金、碳纤维/GA321合金和钢纤维/尿烷复合材料为例,用本文方法对其刚度特性进行理论预报,所得理论预报与试验值吻合很好,说明本文提出的分析模型和方法是有效的.     

High-throughput evaluation of antioxidant and pro-oxidant activities of polyphenols with thymidine protection assays

A recently reported high-throughput screening strategy has been applied to the rapid selection of new water-soluble antioxidants that display strong protective activities. Based on a competitive immunoassay, a triple-screening procedure was used to evaluate the ability of different compounds to protect thymidine under different oxidative stresses. The pro-oxidant effect of norbadione A in the presence of iron was observed, while some pulvinic acid derivatives proved strongly protective during gamma radiolysis, UV irradiation, and Fenton-like oxidation.     

The evolution of water governance in France from the 1960s: disputes as major drivers for radical changes within a consensual framework

ABSTRACT

This paper provides a synthetic presentation of French water governance and its evolution since the 1960s. Through this French experience, it discusses the Organisation for Economic Co-operation and Development (OECD) water governance cycle showing disputes as the main drivers of change. France has been a pioneer in introducing water river basin management some 50 years ago. It is also noted for its water services management by local authorities, leaving a significant role to private and public companies. But French water governance has not been frozen since the 1960s and continues to change radically within a framework based upon its unique history.