Non-Saccharomyces as Biotools to Control the Production of Off-Flavors in Wines

Off-flavors produced by undesirable microbial spoilage are a major concern in wineries, as they affect wine quality. This situation is worse in warm areas affected by global warming because of the resulting higher pHs in wines. Natural biotechnologies can aid in effectively controlling these processes, while reducing the use of chemical preservatives such as SO₂. Bioacidification reduces the development of spoilage yeasts and bacteria, but also increases the amount of molecular SO₂, which allows for lower total levels. The use of non-Saccharomyces yeasts, such as Lachancea thermotolerans, results in effective acidification through the production of lactic acid from sugars. Furthermore, high lactic acid contents (>4 g/L) inhibit lactic acid bacteria and have some effect on Brettanomyces. Additionally, the use of yeasts with hydroxycinnamate decarboxylase (HCDC) activity can be useful to promote the fermentative formation of stable vinylphenolic pyranoanthocyanins, reducing the amount of ethylphenol precursors. This biotechnology increases the amount of stable pigments and simultaneously prevents the formation of high contents of ethylphenols, even when the wine is contaminated by Brettanomyces.     

共振辐射的理论研究——Holstein方程的解

解决介质中共振辐射的关键问题是求解Holstein方程。本文直接利用算符运算将方程积分,给出了激发态粒子集居数的含无限项的级数表达式。基于对这个级数高阶系数的极限行为的研究,成功地克服了无穷项求和的困难,整理出一个在任意给定精度下都只含有限项的解式,由它可以计算出任何时刻的结果。 关键词：     

壳聚糖膜固定生物活性短肽RGDS的研究

为改善壳聚糖对细胞的特异性吸附,采用水溶性碳二亚胺将生物活性短肽精氨酸-甘氨酸-天冬氨酸-丝氨酸(RGDS)固定到壳聚糖膜的表面,采用X射线光电子能谱检测固定多肽前后的壳聚糖膜表面,发现反应后壳聚糖膜表面氮元素含量增大,Nls和Cls曲线拟合谱中酰胺键增多,表明RGDS短肽已固定到壳聚糖膜的表面;人角膜缘上皮细胞体外培养实验表明,固定RGDS后壳聚糖膜的细胞黏附率有了明显提高,固定RGDS后的壳聚糖膜在角膜组织工程支架等方面有更好的应用潜力。     

Astrophysical S-factors from asymptotic normalization coefficients

S-factors for direct capture reactions can be found at astrophysical energies from asymptotic normalization coefficients which provide the normalization of the tail of the overlap function. For example the overlap for ⁸B → ⁷Be+p defines the S-factor for ⁷Be (p, γ)⁸B. Peripheral transfer reactions offer a technique to determine these asymptotic normalization coefficients. As a test of the technique, the ¹⁶O(³He, d)¹⁷F reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of ¹⁷F. The S-factors for ¹⁶O(p, γ)¹⁷F calculated from these ¹⁷F → ¹⁶O+p asymptotic normalization coefficients are found to be in very good agreement with recent measurements. Following the same technique, the ¹⁰B(⁷Be, ⁸B)⁹Be and ¹⁴N(⁷Be, ⁸B)¹³C reactions have been used to measure the asymptotic normalization coefficient for ⁷Be(p, γ)⁸B. This result provides an indirect determination of S ₁₇(0).     

Window consensus PCA for multiblock statistical process control: adaption to small and time‐dependent normal operating condition regions,illustrated by online high performance liquid chromatography of a three‐stage continuous process

A method for multiblock statistical process control is described, involving the computation of Q and D statistics both for individual blocks and for the overall process using window consensus principal components analysis (WCPCA). The approach overcomes two common problems. The first is a small normal operating conditions (NOC) region, which is done by determining the Q‐statistic limits and D statistics using leave‐one‐out (LOO) residuals and scores, rather than employing the residuals and scores of a single training set model obtained from the entire NOC region. The second overcomes the problem of temporal drift of the process and/or measurement technique by updating the NOC covariance matrix to adapt to normal process changes. The unifying multiblock statistical process control and relevant statistics are adapted to cope with these issues and are illustrated in this paper using CPCA as applied to online high performance liquid chromatography (HPLC) of a three‐stage continuous process. Copyright © 2010 John Wiley & Sons, Ltd.     

多谱线耦合系统辐射束缚问题的理论处理

提出一种处理多荧光谱线耦合系统辐射束缚问题的理论方法．这里的耦合包括激发态间的碰撞传能和当谱线重叠时对荧光的交叉吸收．首先将描述辐射束缚的Ｈｏｌｓｔｅｉｎ方程扩展为适用于描述多个激发能级且包括交叉耦合项的微分积分方程组，并将其纳入矢量、矩阵的形式．然后直接通过算符运算求解，给出按算符展开的级数解式．最后对级数解进行约化，导出一个只用有限项便可对系统行为进行完整描述的、远较简单截断近似优越的结果．还给出了一个双激发能级系统的计算实例     

Principal Components plots for exploratory investigation of reactions using ultraviolet-visible spectroscopy: application to the formation of benzophenone phenylhydrazone

The use of Principal Components plots in the exploratory investigation of reactions monitored by UV-Vis spectroscopy is described. The effects of different types of pre-processing (raw, mean-centred, and standardised) are illustrated. Four types of plot (scores versus time, loadings versus wavelength, scores versus scores, and loadings versus loadings) are considered. The approach is used to investigate the reaction between phenylhydrazine and benzophenone to give a hydrazone. Observable deviations from ideal behaviour indicate differential crystallisation of the product, and the presence of small quantities of an intermediate during the reaction. Additional information about the reaction is gained by comparing selected components from several batches. PCA is easily performed at- or on-line, and the information gained can be used to help decide upon a suitable harder model for further analysis.