Global quantification of phosphoproteins combining metabolic labeling and gel‐based proteomics in B. pumilus

Differential proteomics targeting the protein abundance is commonly used to follow changes in biological systems. Differences in localization and degree of post‐translational modifications of proteins including phosphorylations are of tremendous interest due to the anticipated role in molecular regulatory processes. Because of their particular low abundance in prokaryotes, identification and quantification of protein phosphorylation is traditionally performed by either comparison of spot intensities on two‐dimensional gels after differential phosphoprotein staining or gel‐free by stable isotope labeling, sequential phosphopeptide enrichment and following LC‐MS analysis. In the current work, we combined in a proof‐of‐principle experiment these techniques using ¹⁴N/¹⁵N metabolic labeling with succeeding protein separation on 2D gels. The visualization of phosphorylations on protein level by differential staining was followed by protein identification and determination of phosphorylation sites and quantification by LC‐MS/MS. This approach should avoid disadvantages of traditional workflows, in particular the limited capability of peptide‐based gel‐free methods to quantify isoforms of proteins. Comparing control and stress conditions allowed for relative quantification in protein phosphorylation in Bacillus pumilus exposed to hydrogen peroxide. Altogether, we quantified with this method 19 putatively phosphorylated proteins.     

Fermentation Kinetics for Xylitol Production by a Pichia stipitis d-Xylulokinase Mutant Previously Grown in Spent Sulfite Liquor

Spent sulfite pulping liquor (SSL) contains lignin, which is present as lignosulfonate, and hemicelluloses that are present as hydrolyzed carbohydrates. To reduce the biological oxygen demand of SSL associated with dissolved sugars, we studied the capacity of Pichia stipitis FPL-YS30 (xyl3Δ) to convert these sugars into useful products. FPL-YS30 produces a negligible amount of ethanol while converting xylose into xylitol. This work describes the xylose fermentation kinetics of yeast strain P.stipitis FPL-YS30. Yeast was grown in rich medium supplemented with different carbon sources: glucose, xylose, or ammonia-base SSL. The SSL and glucose-acclimatized cells showed similar maximum specific growth rates (0.146 h⁻¹). The highest xylose consumption at the beginning of the fermentation process occurred using cells precultivated in xylose, which showed relatively high specific activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.49). However, the maximum specific rates of xylose consumption (0.19 g_xylose/g_cel h) and xylitol production (0.059 g_xylitol/g_cel h) were obtained with cells acclimatized in glucose, in which the ratio between xylose reductase (EC 1.1.1.21) and xylitol dehydrogenase (EC 1.1.1.9) was kept at higher level (0.82). In this case, xylitol production (31.6 g/l) was 19 and 8% higher than in SSL and xylose-acclimatized cells, respectively. Maximum glycerol (6.26 g/l) and arabitol (0.206 g/l) production were obtained using SSL and xylose-acclimatized cells, respectively. The medium composition used for the yeast precultivation directly reflected their xylose fermentation performance. The SSL could be used as a carbon source for cell production. However, the inoculum condition to obtain a high cell concentration in SSL needs to be optimized. Prepared for 29th Symposium on Biotechnology for Fuels and Chemicals.     

建立在群对称轨道(SMO)及特征组态(CD)基础上的线性分子SMO-CDCI方法

定义和讨论了线性分子的群对称轨道(SMO)及特征组态函数(CD),它能够对线性分子的分子轨道与组态函数进行简单而完全的对称分类.SMO－CDCI方法是一种高效的计算方法,大大节省了线性分子CI计算的机时与内存.     

Anisotropic unstructured mesh adaption for flow simulations

Three new ideas for anisotropic adaption of unstructured triangular grids are presented, with particular emphasis on fluid flow computations. © 1997 John Wiley & Sons, Ltd.     

基于Sigmoid函数局部视觉适应模型的真实影像再现

为解决图像采集与显示设备之间的动态范围差异,色调映射技术试图建立一种由高到低的动态范围映射关系,可用于一般图像的真实影像再现.在不同亮度适应水平下,人眼能产生不同的响应特性及对比度敏感性,从而同时响应不同明暗的光强.由此建立了一种局部视觉适应的再现算法,采用具有参数控制的Sigmoid函数来模拟视觉适应的S形非线性特点,得到不同局部亮度适应水平下的压缩曲线,因此能较好地协调图像整体对比度、亮度调整与局部增强之间的关系,在增强图像较暗区域的同时,极大程度地保持亮区细节.经主观评价与特征统计参数相结合的方法验证,该算法能有效地实现动态范围压缩,保持图像细节而避免伪像,具有一定的色彩恒定性,且复杂度低,具有很好的实用性.     

企业内部的随机分权

在一个信息传递模型框架中考察多部门组织内部权力的随机配置. 研究结论表明,在特定参数范围内,随机分权能提升组织治理局部适应和部门协调的能力;而且,数值分析表明最优组织结构下的集权概率随着部门协调需求和部门经理层激励冲突的上升而增加. 因此,组织主动引入权力配置不确定性本身可能就是最优组织结构的组成部分,从而为随机分权提供了一种理论解读.     

A New Universal Domain Adaptive Method for Diagnosing Unknown Bearing Faults

The domain adaptation problem in transfer learning has received extensive attention in recent years. The existing transfer model for solving domain alignment always assumes that the label space is completely shared between domains. However, this assumption is untrue in the actual industry and limits the application scope of the transfer model. Therefore, a universal domain method is proposed, which not only effectively reduces the problem of network failure caused by unknown fault types in the target domain but also breaks the premise of sharing the label space. The proposed framework takes into account the discrepancy of the fault features shown by different fault types and forms the feature center for fault diagnosis by extracting the features of samples of each fault type. Three optimization functions are added to solve the negative transfer problem when the model solves samples of unknown fault types. This study verifies the performance advantages of the framework for variable speed through experiments of multiple datasets. It can be seen from the experimental results that the proposed method has better fault diagnosis performance than related transfer methods for solving unknown mechanical faults.     

叶绿素荧光技术对受Cu~(2+)胁迫藻类暗适应时间的研究

利用叶绿素荧光技术,对受相同浓度Cu2+胁迫的蛋白核小球藻、斜生栅藻、铜绿微囊藻的最佳暗适应时间进行研究.通过对三种供试藻在光照和暗适应时间分别为30s、1min、3min、5min、10min和20min条件下的光合荧光参量进行测定,以光化学淬灭参量值为主要参考依据,结合t检验方法对暗适应时间进行显著性差异分析,结果表明:暗适应条件下三种供试藻的潜在最大量子效率值略有增加,实际量子效率值基本保持不变;蛋白核小球藻和斜生栅藻的光化学淬灭参量值和非光化学淬灭参量值随暗适应时间的延长显著增加;铜绿微囊藻光化学淬灭参量值在光照1min时达到最大,无需进行暗适应,这可能与蓝藻在暗适应时发生状态转换有关;藻类不是暗适应时间越长越好,蛋白核小球藻和斜生栅藻的最佳暗适应时间分别为5min和10min.这将为采用叶绿素荧光技术进一步研究毒物对藻类的胁迫机理提供可靠依据.     

Locally adaptive Nakagami-based ultrasound similarity measures

The derivation of statistically optimal similarity measures for intensity-based registration is possible by modeling the underlying image noise distribution. The parameters of these distributions are, however, commonly set heuristically across all images. In this article, we show that the estimation of the parameters on the present images largely improves the registration, which is a consequence of the more accurate characterization of the image noise. More precisely, instead of having constant parameters over the entire image domain, we estimate them on patches, leading to a local adaptation of the similarity measure. While this basic idea of creating locally adaptive metrics is interesting for various fields of application, we present the derivation for ultrasound imaging. The domain of ultrasound is particularly appealing for this approach, due to the inherent contamination with speckle noise. Furthermore, there exist detailed analyses of suitable noise distributions in the literature. We present experiments for applying a bivariate Nakagami distribution that facilitates modeling of several scattering scenarios prominent in medical ultrasound. Depending on the number of scatterers per resolution cell and the presence of coherent structures, different Nakagami parameters are required to obtain a valid approximation of the intensity statistics and to account for distributional locality. Our registration results on radio-frequency ultrasound data confirm the theoretical necessity for a spatial adaptation of similarity metrics.     

Self‐organizing traffic lights at multiple‐street intersections

The elementary cellular automaton following rule 184 can mimic particles flowing in one direction at a constant speed. Therefore, this automaton can model highway traffic qualitatively. In a recent paper, we have incorporated intersections regulated by traffic lights to this model using exclusively elementary cellular automata. In such a paper, however, we only explored a rectangular grid. We now extend our model to more complex scenarios using an hexagonal grid. This extension shows first that our model can readily incorporate multiple‐way intersections and hence simulate complex scenarios. In addition, the current extension allows us to study and evaluate the behavior of two different kinds of traffic‐light controller for a grid of six‐way streets allowing for either two‐ or three‐street intersections: a traffic light that tries to adapt to the amount of traffic (which results in self‐organizing traffic lights) and a system of synchronized traffic lights with coordinated rigid periods (sometimes called the “green‐wave” method). We observe a tradeoff between system capacity and topological complexity. The green‐wave method is unable to cope with the complexity of a higher‐capacity scenario, while the self‐organizing method is scalable, adapting to the complexity of a scenario and exploiting its maximum capacity. Additionally, in this article, we propose a benchmark, independent of methods and models, to measure the performance of a traffic‐light controller comparing it against a theoretical optimum. © 2011 Wiley Periodicals, Inc. Complexity, 2012