Mutagenicity and genotoxicity of sorbic acid-amine reaction products

Sorbic acid (E200) and its salts (potassium and calcium sorbate: E202 and E203) are allowed for use as preservatives in numerous processed foods. Sorbic acid had a conjugated system of double bonds which makes it susceptible to nucleophilic attack, sometimes giving mutagenic products. Under conditions typical of food processing (50-80°C), we analysed the cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines. Mutagenesis studies, involving Ames' test and genotoxicity studies with HeLa cells and plasmid DNA, showed that none of the products studied presented either mutagenic or genotoxic activities.     

探索三维与二维技术的桥梁——毕业设计《Colorful Days》制作始未

片名:Colorful Days片长:3分50秒(加片头片尾共4分30秒)类型:动画MV,三维与二维动画结合制作周期:6个月作为大学毕业的毕业设计《,Colorful Days》是我四年大学学习的总结。当我去年还在搜索题材和剧本的时候,朴树的歌曲《Colorful Days》吸引了我。《ColorfulDays》是什么?它是一首歌曲,是一部音乐电视,是MV,又是一个广告,是一部短片,更是一位歌手精神的抒发……在这个有声有画的4分钟的视听语言中,包含了太多的东西,艺术与商业在这里完美的结合。如此动听的歌曲,让我产生了共鸣。第一次听到这首歌曲的时候,各种画面在我脑中闪现。因…     

Real-time droplet caliper for digital microfluidics

We developed an optical, microfabrication-free approach for performing real-time measurements of individual droplet characteristics (frequency of production, velocity, and length) flowing in a transparent microfluidic channel. Our approach consists in an interpretation of the differential signal produced by a pair of photodiodes connected head-to-tail due to the variations of illumination at the passage of a droplet. We checked the relevance of this zero-background method by comparing results to video measurements, and observed a very good agreement at rates up to the kHz range. Moreover, since the measured values are stored in a simple text file, flow characterization over very long times (several hours) becomes accessible. We applied this facility to perform three examples of long-term studies: stationary regimes, transient regimes, and the effect of an external forcing. Several unexpected features, like long-period fluctuations, can thus be evidenced.     

Influence de la densité électronique du plasma sur les produits de condensation d'une pulvérisation cathodique réactive de cuivre dans l'oxygène

Electron density in a reactive sputtering plasma is controlled by means of high frequency magnetic induction or by using polarised grids. We observe changes in yield diagrams in good agreement with the phenomenological theory proposed by our laboratory. For the particular case of copper sputtered in oxygen we prove that the chemical reaction is initiated inside the plasma by using a transvérse magnetic field.     

PREVISE: A knowledge-based system to support the preparation and verification of space operations procedures

This paper presents the Previse system for preparing and verifying operations procedures, developed in the frame of a project conducted by Matra Marconi Space for the European Space Agency ESA/ESTEC. This knowledge-based system supports an evolutive procedures language (syntax and vocabulary). It improves the efficiency of procedures preparation by providing powerful editing facilities, by checking the validity of the syntax used by procedures writers, and by automating the formatting task. It also provides a set of verification mechanisms allowing to detect different types of semantic errors in procedures.     

Simple interferometric technique for generation of a radially polarized light beam

We present a theoretical and experimental investigation of an interferometric technique for converting a linearly polarized Gaussian beam into a radially polarized doughnut beam. The experimental setup accomplishes the coherent summation of two orthogonally polarized TEM01 and TEM10 beams that are obtained from the transformation of a TEM00 beam by use of a simple binary diffractive optical element. We have shown that the degree of radial polarization is maximum at a given distance from the interferometer output port that depends on the diameter of the incident beam at the interferometer input port.