Quantifying biochemical variables of corn by hyperspectral reflectance at leaf scale

To further develop the methods to remotely sense the biochemical content of plant canopies, we report the results of an experiment to estimate the concentrations of three biochemical variables of corn, i.e., nitrogen （N）, crude fat （EE） and crude fiber （CF） concentrations, by spectral reflectance and the first derivative reflectance at fresh leaf scale. The correlations between spectral reflectance and the first derivative transformation and three biochemical variables were analyzed, and a set of estimation models were established using curve-fitting analyses. Coefficient of determination （R2）, root mean square error （RMSE） and relative error of prediction （REP） of estimation models were calculated for the model quality evaluations, and the possible opti- mum estimation models of three biochemical variables were proposed, with R2 being 0.891, 0.698 and 0.480 for the estimation models of N, EE and CF concentrations, respectively. The results also indicate that using the first derivative reflectance was better than using raw spectral reflectance for all three biochemical variables estimation, and that the first derivative reflectances at 759 nm, 1954 nm and 2370 nm were most suitable to develop the estimation models of N, EE and CF concentrations, respectively. In addition, the high correlation coefficients of the theoretical and the measured biochemical parameters were obtained, especially for nitrogen （r=0.948）.     

Influence on the Quality of Apocynum Venetum with Different Degumming Methods

The biochemical degumming and chemical degumming were employed to process apocynum venetum, and indices values for the residual gum content, fineness, strength of single fiber, average length, moisture regain and whiteness of degummed apocynum venetum fibers are evaluated with fuzzy mathematical method. The results obtained from this investigation show that the general index value of degummed apocynum venetum fibers with biochemical degumming （K1=0.626 09） is prior to that with chemical degumming （K2 =0.421 64）.     

Rapid cold hardening process of insects and its ecologically adaptive significance

In contrast to overwintering cold hardening, a rapid cold hardening process has recently been described in insects. This process can rapidly enhance cold tolerance of insects in several hours or even minutes. The characteristics of rapid cold hardening include inducing conditions, cold hardening effects, and fitness costs. Physiological and biochemical mechanisms of rapid cold hardening include rapid changes in the phospholipid composition and the increase in hemolymph osmolalities, polyols production, proline and cold-induced proteins. Moreover, there are different views about the ecologically adaptive significance of rapid cold hardening in insects. This paper reviews research results about rapid cold hardening of insects since 1987, focusing on forms of cold injury, strategies of cold tolerance, and definitions, characteristics, physiological and biochemical mechanisms and adaptive significance of rapid cold hardening.     

Alternative Respiration Induced by Glucose Stimulation and Variation of Adenylate Energy Charge in Glucose-Starved Cells of Green Alga Chlorella Protothecoides

IntroductionCyanide- resistant or alternative respiration hasbeen reported to be widespread in higher plants,phytoplanktons and microorganisms[13 ] . Thestudies of the inhibitor- resistant respiration havecontributed much to the understanding of theorganization and control of complex intracellularrespiratory systems and biochemical processes.Grant and Hommersand[4 ,5] examined theinhibitor- resistantrespiratory characteristics of thegreen alga Chlorella protothecoides grown in highconcentrati…     

Studies on the overexpression of the soybean GmNHX1 in Lotus corniculatus： The reduced Na^＋ level is the basis of the increased salt tolerance

Soil salinity is one of the major factors reducing plant growth and productivity. The detrimental effects of salt on plants are a consequence of both a water deficit resulting in osmotic stress and the excess so- dium ions on critical biochemical processe…     

全球招聘新闻(英文)

博士后岗位[美国]Cleveland ClinicCleveland Clinic opens NIH-funded positions to study newly discovered transmembrane proteases involved in cardiovascular disease.Research projects include biochemical analysis of novel enzymes and phenotypic characterization of     

Distribution of lanthanum among the chloroplast subcomponents of spinach and its biological effects on photosynthesis:location of the lanthanum binding sites in photosystem II

Positive, nil and/or negative effects of REEs on crops’ growth and yield were observed by room cultivation or field experiments in many countries. Especially in China, rare earth elements (REEs) containing fertilizers were applied to more than 300 species of field crops, and re-sulted in a mean productivity increase of 5%―15%[1]. Since the 1970s many approaches in the understanding of physiological and biochemical effects of REEs on plantmetabolism, yield and quality have been made[2―4]…     

Monitoring of Cerebral Oxygenation by Near-infrared Spectroscopy during Cardiopulmonary Bypass in Infants

Objective： To evaluate the use of near-infrared spectroscopy for monitoring cerebral oxygenation under different cardiopulmonary bypass models. Method： Twenty-four patients with ventricular septal defect and pulmonary hypertension undergoing open-heart surgery were assigned eight each to three groups, with respect to different cardiopulmonary bypass models： moderate hypothennia cardiopulmonary bypass, deep hypothennia low flow and deep hypothennia circulatory arrest. For each patient, cerebral oxygenation with near-infrared spectroscopy were monitored and the relative concentration changes in cerebral oxygenated hemoglobin, deoxygenated hemoglobin and oxidized cytochrome aa3 were calculated. Electroencephalography, biochemical indicators such as neuron-specific enolase and lactate, and performed correlation analyses for nearinfrared spectroscopy data and biochemical indicators were also measured. Results： Near-infrared spectroscopy data and biochemical indicators for moderate hypothennia cardiopulmonary bypass and deep hypothennia low flow group showed no correlation. For deep hypothennia circulatory arrest group, oxygenated hemoglobin signal declined to a plateau （nadir） during the circulatory arrest period. The duration from reaching nadir until reperfusion ＂oxygenated hemoglobin signal nadir-time＂, and the minimum values of oxygenated hemoglobin, and oxidized cytochrome aa3 were closely correlated with increasing neuron-specific enolase and lactate. And, all patients whose oxygenated hemoglobin signal nadir-time was less than 35 rain were free from behavioral evidence of brain injury. Conclusion： Near-infrared spectroscopy data including oxygenated hemoglobin signal nadir-time and the minimum of oxygenated hemoglobin and oxidized cytochrome aa3 showed strong correlation with other cerebral function assessment for deep hypothermia circulatory arrest. Oxygenated hemoglobin signal nadir-time determined by near-infrared spectroscopy can be useful in predicting the safe duration of circulatory arrest.     

全球招聘新闻(英文)

正博士后[美国]New York University New York University opens a postdoctoral position.They are in search of highly motivated,creative individuals with a strong interest in epithelial biology.They are presently focusing their efforts on bacterial/host urothelial interactions,membrane trafficking and urothelial stem cells using a combination of cell culture,transgenic mouse and a wide range of biochemical,molecular and cell biological techniques.Applicants should have a     

ADP-flow velocity profile to interpret hydromorphological features of China''''s Yangtze Three-Gorges valley

Land and sea are linked closely by large rivers throughrunoff and sediment discharging and biochemical materialtransferring into the sea[1?3]. The processes carried out byenergy exchange have been in a sensitive response toglobal change[4]. To study the mechanism of sediment transport in the river basin as to reflecting hydromor- phological and climatological controls is thus becoming vital for earth scientists, at present and in the near future since any change in fluvial landform is of a gre…     

Progress in the applications of flux analysis of metabolic networks

The metabolic network has become a hot topic in the area of system biology and flux-based analysis plays a very important role in understanding the characteristics of organism metabolic networks. We review mainly the static methods for analyzing metabolic networks such as flux balance analysis (FBA), minimization of metabolic adjustment (MOMA), regulatory on / off minimization (ROOM), and dynamic flux balance analysis with linear quadratic regulator (DFBA-LQR). Then several kinds of commonly used software for flux analysis are introduced briefly and compared with each other. Finally, we highlight the applications of metabolic network flux analysis, especially its usage combined with other biological characteristics and its usage for drug design. The idea of combining the analysis of metabolic networks and other biochemical data has been gradually promoted and used in several aspects such as the combination of metabolic flux and the regulation of gene expression, the influence of protein evolution caused by metabolic flux, the relationship between metabolic flux and the topological characteristics, the optimization of metabolic engineering. More comprehensive and accurate properties of metabolic networks will be obtained by integrating metabolic flux analysis, network topological characteristics and dynamic modeling.     

布尔基因网络及其研究

基因网络模型将为深入理解生命本质提供了一个新的研究框架和平台。布尔网络是研究基因网络的一个有力工具。这里阐述利用布尔网络时基因调控网络建模的机理，介绍了基于布尔网络的基因网络的研究现状和最新进展。最后指出了谊方法的局限和下一步的研究方向。     

Network Visualization in Cell Biology

Many of the processes known to take place in biological cells are analyzed in the form of different types of network.The complexity of these networks increases along with our knowledge of these processes,making their analysis more difficult.Network visualization is a powerful analysis method that will have to be developed further to deal with this complexity.This survey provides a brief overview of network visualization in general,followed by an in-depth discussion of its application to three network types specific to cell biology,namely gene regulatory,protein interaction,and metabolic networks.Finally,we discuss the difficulty of visually integrating these network types and trying to compare networks of cells that belong to different organisms.     

无线传感器网络质心定位算法的OPNET仿真实现

在研究无线传感器网路节点定位技术的过程中,针对搭建硬件实验平台不易实现的问题,使用OPNET MODELER对节点定位技术进行仿真建模.在分析无线传感器网络特点的基础上,合理选择无线链路的管道阶段,构建接近真实的无线网络环境,给出了仿真模型,精确刻画了质心定位算法在网络节点定位中的具体应用过程.结果表明,通过建立节点、...     

OPNET的关键技术研究

网络仿真是一种新的网络规划和设计技术,OPNET可以完成各种通信系统的仿真,包括核心网、接入网、无线网络、卫星网络以及各种混合型网络等。文章介绍了功能强大的网络建模和仿真工具OPNET,研究了OPNET采用的关键仿真技术,给出了一个OPNET在学校局域网扩展中的应用实例。     

热力系统的计算机集成设计系统

为帮助热力系统的设计人员快速、准确地掌握复杂系统的动、静态特性，保证热力系统的优化设计和安全运行，研制了高起点、多功能的热力系统仿真研究系统－清华计算机集成设计系统（ＴＨＣＩＤＳ），它由建模系统、仿真研究集成环境、数采与测试系统、可视化环境与仿真器开发四部分组成。该系统采用了图形化及模块化建模、计算机网络等新技术和方法，可以进行热力系统的设计、方案比较、系统特性研究、控制系统的设计、控制规律和策略的研究以及软硬件的测试等，并具有良好的开放性和可扩充性。     

癌症的系统生物学模型研究进展

系统生物学研究采用的是系统性的研究方法,即获取并整合目标系统不同层次的生物学信息,构建适用于该生物系统的数学模型,对该系统的特征性行为进行系统性研究.癌症是一种复杂的生物系统,已成为系统生物学研究的热点领域.癌症的系统生物学模型是对传统的癌症动物模型的补充,主要包括:统计推断模型、生化网络模型、以及组织水平模型等.本文综述了这些系统模型方法在癌症研究中的应用情况及其取得的重要研究成果.     

基于 ASP． NET 的全景激光测绘系统设计

为解决传统测绘行业测绘数据不能实时绘图、实时成像、数据和图像的快速整合建模等问题,设计了基于 Web 平台,集树莓派、嵌入式微处理器和智能移动平台于一体的全景激光测绘系统。该系统使用激光雷达作为对测绘区域的数据采集工具,利用 NＲF24L01 无线收发器和 Wi-Fi 模块进行数据的发送和接收,运用树莓 派和 STM32 微处理器对数据进行分析和处理,用户可使用 Web 客户端对图像和数据进行查询。系统利用智能移动平台测量数据,于网络平台实现数据存储,并实现了测绘数据的快速建模与成像。实验结果表明,该系统既能完成测绘区域点间距、局部面积、全面积测量,历史数据重建及全景图像滚动显示,又能在强光、无光、山地和隧道等苛刻环境条件下低功耗稳定运行。该系统结合软件算法和用户友好操作界面,提高了在工程建设中解决定向、测距、测高问题的时效性,同时增添了图像与数据实时融合的测绘手段,极大地减少了装机量和测绘周期。     

Design principles of a bacterial signalling network

Cellular biochemical networks have to function in a noisy environment using imperfect components. In particular, networks involved in gene regulation or signal transduction allow only for small output tolerances, and the underlying network structures can be expected to have undergone evolution for inherent robustness against perturbations. Here we combine theoretical and experimental analyses to investigate an optimal design for the signalling network of bacterial chemotaxis, one of the most thoroughly studied signalling networks in biology. We experimentally determine the extent of intercellular variations in the expression levels of chemotaxis proteins and use computer simulations to quantify the robustness of several hypothetical chemotaxis pathway topologies to such gene expression noise. We demonstrate that among these topologies the experimentally established chemotaxis network of Escherichia coli has the smallest sufficiently robust network structure, allowing accurate chemotactic response for almost all individuals within a population. Our results suggest that this pathway has evolved to show an optimal chemotactic performance while minimizing the cost of resources associated with high levels of protein expression. Moreover, the underlying topological design principles compensating for intercellular variations seem to be highly conserved among bacterial chemosensory systems.     

面向Windows平台的日志远程采集系统研究

对日志进行远程集中化管理是日志管理的有效手段.但由于日志格式不统一,传统上很难将大型网络中Windows系统上的各类日志远程采集到集中的日志服务器.介绍了Windows平台上常见系统日志的概况,以及一种新的支持多平台且功能强大的日志采集工具nxlog,它可以非常方便地部署到Windows系统上并以客户端代理或者服务器模式运行,以此提出了基于nxlog的日志远程采集系统方案.实际运行结果表明,该方案具有实用、高效的特点,可有效解决大型网络中Windows系统日志远程采集的问题.