内源淀粉特性比较研究

本文比较了不同内源淀粉粒大小、组成、结构特征的差异,分析了造成差异的生理及组成的分子基础,其结论为直链淀粉脂类复合物及蛋白质含量低,分子间氢键和共价键形成容易,淀粉粒大,溶胀能力强和支键淀粉含量高的淀粉,其淀粉糊胶粘度高溶液稳定性和增稠能力强,是以粘性和增稠力为目的的淀粉原料理想的组成和结构模式。     

淀粉的改性及其在可降解塑料和橡胶中的应用研究

淀粉作为一种天然高分子,由于其价格低,可再生,生物降解性好等优点,在材料制备与改性方面得到了人们的青睐.同时由于淀粉所固有的亲水性,难于加工性以及和石化材料间较差的相容性等也大大限制了其在非食品工业中的应用范围.本文介绍了国内外淀粉改性的最新进展及其尝试其在可降解塑料和橡胶方面的应用研究,并就目前该领域存在的一些问题作了初步探讨.     

武汉地区24个豆科品种种子萌发期耐盐性评价

选取了武汉地区常见的24个豆类品种进行实验,比较其在不同浓度Na Cl溶液下发芽率、发芽指数、胚根胚芽比的生理指标差异。结果显示,在相同Na Cl浓度下,不同品种的发芽率、发芽指数、胚根胚芽比差异极显著(P0.01),品种间发芽率的变异系数随着Na Cl浓度的增加而加大,在150 mol/L时达到最大,且各品种间的发芽率、发芽指数、胚根胚芽比差异均极显著,品种间各指标差异最大。聚类分析表明,Na Cl浓度150 mol/L可作为豆科种子萌发期耐盐性鉴定的最佳浓度。     

行播作物热辐射方向性规律探讨

作物常以行结构方式播种,行结构能引起作物垄间光照土壤和垄内阴影土壤间较大的温度差异,且在方位角上可导致明显的正像元组分构成差异,这些差异使行播作物在方位角和天顶角上同时存在热辐射方向性变化．将作物行结构方式当作随机播种方式来处理,显然会使热辐射方向性产生较大的误差．为消除误差,有必要研究行播作物的热辐射方向性规律．用 Ｍｏｎｔｅ Ｃａｒｌｏ方法模拟行播结构参数对作物热辐射方向性的影响,模拟结果表明：垄宽、垄高、垄间距和叶面积指数等参数对热辐射方向性的影响都比较明显,但影响最大的因素是观测方位角．     

泥沙颗粒表面电荷分布的初步研究

泥沙颗粒表面电荷分布，是研究其与污染物之间吸附和解吸的基础．本文以石英砂颗粒为例，利用扫描探针显微镜（SPM）中的静电力显微镜（EFM）测量技术，用相位成像模式测量了石英砂颗粒表面的微形貌和电荷分布，并统计了两者间的关系．研究表明，石英砂颗粒表面形貌复杂，表面形貌对电荷分布影响较大，电荷大多集中在颗粒表面的鞍部、凸起和凹地部位，而在凹槽、凸脊和平坦部位分布较少．上述研究为揭示其吸附机理和进一步研究天然河流泥沙颗粒的相关性质奠定了基础．     

基于表面间距离度量的多视点距离图像的对准算法

现有的距离图像对准算法，一般是采用最近点之间的距离和作为评价函数来估计运动参数．这种基于点对间距离的评价函数的缺点是，不同距离图像之间的最近点不一定是物体表面同一点的采样，而且不同采样点所代表的物体表面面积也不同．这些问题使得基于点对间距离度量的对准算法存在不精确对应的问题，因而对准精度不高，对初始运动参数敏感．提出一种基于表面间距离度量的对准算法．通过构造三角网格来近似表示物体的表面，采用三角网格间最近距离的均值作为评价函数来估计运动参数．推导并简化了表面间距离计算的积分公式．实验结果表明，该算法有较高的对准精度，而且收敛速度较快，抗噪声能力较强．     

船用柴油机第一道活塞环岸积碳的微观形貌和孔隙特性的相衬显微CT研究

大型二冲程船用柴油机具有热负荷高、燃用重油、润滑油参与燃烧及其变质、颗粒物排放高等特点,直接或间接地导致其燃烧室内更为明显的积碳现象,同时积碳层的构成和特性会显著影响柴油机的输出动力性能和排放特性．采用我国第三代同步辐射装置一上海光源的x射线相衬显微CT技术,对第一道活塞环岸积碳样品进行了三维无损显微成像．通过定量数字图像处理,对积碳层的微观特性和孔隙分布特性进行了分析研究．结果表明,活塞环上部积碳厚度基本在1．0mm左右,仅为缸套和活塞间距的一半,但是其表面形态显示出与缸套强烈的摩擦磨损痕迹,这说明该部位的积碳会明显破坏缸套的滑油分布．同时积碳内外表面裂纹密集,而中部裂纹较疏松,积碳内外表面的裂纹形成机理存在显著差异．从孔隙连通性来看,几乎所有的裂缝都是相通的,计算得到的总的孔隙率在10．9％～12．8％之间．并且连通的裂纹中存在交汇的孔洞结构,这些孔隙结构可能对燃气产生吸附和解吸的作用．     

OH-根对掺铒碲酸盐玻璃光谱性质的影响

制备了5种浓度下系列不同OH^-根含量的掺铒碲酸盐玻璃样品，测试了样品的红外吸收光谱，分析了在不同通氧除水时间下玻璃的红外吸收系数变化情况．测试了样品的吸收光谱，利用Judd-Ofelt理论计算了不同铒掺杂浓度和OH^-根含量样品的光谱参量Ωi（i=2，4，6）．根据McCumber理论计算了铒离子在1532nm处的吸收截面和Er^3＋：^4I13／2→^4I15/2跃迁峰值发射截面．测试了样品中Er^3＋：^4I13／2→^4I15/2跃迁对应的荧光光谱和^4I13／2能级荧光寿命，讨论了OH^-根对不同铒掺杂浓度下碲酸盐玻璃光谱性质的影响．研究结果表明，OH^-根仅对荧光寿命和荧光峰值强度存在影响，在Er2O3浓度小于1．0mol％时，OH^-根是发生荧光猝灭的主要影响因素，而高于这一浓度后Er^3＋离子本身的能量转移对荧光猝灭起主要作用．而OH^-根对其他光谱性质（荧光半高宽、吸收光谱、受激发射截面等）基本没有影响．     

组合摩擦材料研究

由于国内外摩擦材料的研究仍处于经验阶段，我们提出组合摩擦材料的概念并进行了组合摩擦材料研究，旨在解决摩擦材料配方研究中存在的三个问题：如何选择原材料，如何匹配原材料含量和摩擦材料性能优化。组合摩擦材料研究包括用组合方法筛选和评价原材料和用黄金分割法优化摩擦材料配方是解决经验地尝试法研究摩擦材料配方的一个有效途径。用组合方法筛选和评价原材料，通过组合路线考察原材料间的相互作用，寻找具有协同效应的原材料组合规律，可以合理选择原材料和合理设计摩擦材料配方。用黄金分割法可以优化摩擦材料性能。通过组合摩擦材料研究可以实现摩擦材料的研究从经验走向科学。两个实例证明了组合摩擦材料研究的可行性。     

亚洲人群p53Arg72Pro基因多态性与胃癌易感性的Meta分析

目的探讨p53基因多态性与亚洲人群胃癌易感性的关系。方法检索PubMed、EMbase、The Cochrane Library和CBM、中国学术文献总库、维普、万方数据库,收集有关p53基因多态性与亚洲人群胃癌易感性有关的文献,最后检索日期为2014年5月,并追溯纳入研究的参考文献。由两位研究者按照纳入与排除标准独立筛选文献、提取资料和评价质量后,采用Stata13.0统计软件进行统计分析。以病例组及对照组p53基因型分布的比值比(OR值)为效应指标,计算合并OR值及95%可信区间,用漏斗图和Egger图评估。结果在亚洲人群中,病例组和对照组相比,携带杂合基因型(Arg/Pro)和突变纯合基因型(Pro/Pro)的个体发生胃癌的风险和野生纯合型(Arg/Arg)相比差异有统计学意义(OR=1.159,95%CI:1.025~1.331,P=0.019)(P0.05)。结论与野生纯合型相比,携带杂合基因型和突变纯合基因型增加了患胃癌的风险。     

Differential lethality following treatment with ionizing radiations of various energies in Drosophila

Male and female gametes of Drosophila were treated with various doses of ionizing radiations: X-rays at different energy, and gamma-rays from 2 sources given singly and in 2 temporal sequences. The induced lethality was assessed in successive developmental stages by scoring the number of eggs, larvae and adults. The results clearly show that the effects of various radiations appear in terms of difference among developmental stages and/or between treated sexes/genotypes. It is suggested that the various energies affect different gene functions which are not completely independent, as supported by the non-additive effects of the two temporal sequences.     

Le degré de polymérisation de l'amylose,de l'amylopectine et du glycogène

Summary A colorimetric method based on the reducing power of the aldehydic end group has been developed in order to determine the M. W. of polysaccharides. It has been found that corn amylose contains chain molecules of much higher degree of polymerization than potato amylose.     

Differential lethality following treatment with ionizing radiations of various energies inDrosophila

Summary Male and female gametes ofDrosophila were treated with various doses of ionizing radiations: X-rays at different energy, and gamma-rays from 2 sources given singly and in 2 temporal sequences. The induced lethality was assessed in successive developmental stages by scoring the number of eggs, larvae and adults. The results clearly show that the effects of various radiations appear in terms of difference among developmental stages and/or between treated sexes/genotypes. It is suggested that the various energies affected different gene functions which are not completely independent, as supported by the non-additive effects of the two temporal sequences.Acknowledgments. The authors wish to thank Prof. D.L. Palenzona for valuable discussion and criticism and Mrs C. Brunaleschi and Mr E. Boschieri for their technical assistance.     

Nutritional requirements of aeromonads and their multiplication in drinking water

Aeromonads can utilize a wide range of low molecular-weight compounds, including amino acids, carbohydrates and long-chain fatty acids at a concentration of a few micrograms per liter. Utilization of biopolymers such as gelatin, casein and amylose is slow at this concentration level. The concentration of substrates available for an A. hydrophila strain in drinking water was usually below 10 micrograms of C/l. The autochthonous bacteria utilized these substrates more rapidly than the aeromonads. The multiplication of aeromonads in drinking water during distribution is therefore explained by their growth on biomass components in the biofilm and in sediments in the pipes.     

Forecasting the US Term Structure of Interest Rates Using Nonparametric Functional Data Analysis

In this paper we consider a novel procedure to forecasting the US zero coupon bond yields for a continuum of maturities by using the methodology of nonparametric functional data analysis (NP‐FDA). We interpret the US yields as curves since the term structure of interest rates defines a relation between the yield of a bond and its maturity. Within the NP‐FDA approach, each curve is viewed as a functional random variable and the dynamics present in the sample are modeled without imposing any parametric structure. In order to evaluate forecast the performance of the proposed estimator, we consider forecast horizons h = 1,3,6,12… months and the results are compared with widely known benchmark models. Our estimates with NP‐FDA present predictive performance superior to its competitors in many situations considered, especially for short‐term maturities. Copyright © 2016 John Wiley & Sons, Ltd.     

A new pattern of hermaphroditism (inducible hermaphroditism) in populations ofOphryotrocha labronica (Annelida Polychaeta)

Summary A new kind of hermaphroditism, which is called inducible hermaphroditism, has been discovered in the otherwise gonochoristic populations ofOphryotrocha labronica of the Gulf of Naples and of the Lagune of Venice. Inducible hermaphrodites, which are fertile in both the male and female phases, represent 25.8% and 31.8% of the Naples and Venice strains respectively. Inducible hermaphrodites are obtained when pairs between adult females — or female phase hermaphrodites — and juveniles are formed. Crosses between inducible hermaphrodites, in different sex phases, pure male and female individuals give progenies whose sex ratios are clearly correlated with the sex genotypes of the parents.     

The balance between immunity and tolerance: The role of Langerhans cells

Langerhans cells are immature skin-homing dendritic cells that furnish the epidermis with an immune surveillance system, and translate information between the internal and external milieu. Dendritic cells, in particular Langerhans cells, are gaining prominence as one of the potential principal players orchestrating the decision between immunity and tolerance. Langerhans cells capture aberrant self-antigen and pathogen-derived antigen for display to the efferent immune response. Recent evidence suggests redundancy in the antigen-presenting function of Langerhans cells, with dermal dendritic subsets capable of fulfilling an analogous role. There is mounting evidence that Langerhans cells can cross-prime T cells to recognize antigens. Langerhans cells are proposed to stimulate T regulatory cells, and are implicated in the pathogenesis of cutaneous T cell lymphoma.The phenotype of Langerhans cells, which may be tolerogenic or immunogenic, appears to depend on their state of maturity, inciting immunogen and cytokine environment, offering the potential for manipulation in immunotherapy. Received 6 August 2008; received after revision 18 September 2008; accepted 13 October 2008     

Phytotoxins as tools in breeding and selection of disease-resistant plants

Conventional plant breeding for resistance to pathogens, although successful, is in many cases still too slow to keep pace with pathogen adaptation, and suffers from the lack of genetic variability in cultivated varieties. Phytotoxins, because of their role in disease development, have been proposed as convenient markers for early screening of resistant genotypes and as selective agents for in vitro selection. The present review summarizes, firstly, the evidence for a genetic correlation between tolerance to toxins and resistance to pathogens, with particular reference to host-selective toxins (HST) and factors affecting early screening. There follows a discussion of results obtained from the use of phytotoxins for in vitro selection of resistant plants. The conclusion is drawn that this practice, while potentially useful in the case of HST, leads to contradictory results when ill-defined toxins or culture filtrates are used. Finally, prospects for future research are adumbrated.     

Forecasting interest rates through Vasicek and CIR models: A partitioning approach

The aim of this paper is to propose a new methodology that allows forecasting, through Vasicek and CIR models, of future expected interest rates based on rolling windows from observed financial market data. The novelty, apart from the use of those models not for pricing but for forecasting the expected rates at a given maturity, consists in an appropriate partitioning of the data sample. This allows capturing all the statistically significant time changes in volatility of interest rates, thus giving an account of jumps in market dynamics. The new approach is applied to different term structures and is tested for both models. It is shown how the proposed methodology overcomes both the usual challenges (e.g., simulating regime switching, volatility clustering, skewed tails) as well as the new ones added by the current market environment characterized by low to negative interest rates.