基于近红外光谱技术的白茶可溶性糖总量快速测定研究

本文以积分球漫反射模块采集113份不同等级不同年份的白茶近红外光谱图并进行预处理分析,采用蒽酮比色法对来自不同厂家的白茶进行含量测定,运用偏最小二乘法(PLS)建立了白茶可溶性糖总量快速测定模型并对模型进行验证。试验结果表明所建立模型的相关系数(R)为0. 963,校正均方根差(RMSEC)为0. 363 9,验证均方根差(RMSEP)为0. 349,验证集平均相对误差为3. 11%。通过NIRS快速测定白茶总糖含量具有较高的可行性,该方法预测结果较好,能够准确、快速、无损的对白茶可溶性糖总量进行快速定量分析。     

波长选择SCARS和偏最小二乘法建立香菇中多糖含量预测的近红外光谱模型

为实现香菇多糖含量的快速测定,利用近红外光谱漫反射技术采集了60个香菇粉末样本在12000~3800 cm-1范围内的光谱数据,利用紫外可见光谱法测定了香菇粉末样品的多糖含量。采用多种化学计量学方法,剔除掉四个异常样本后,考察了不同的光谱预处理方法以及波长选择对模型的影响,用留一交互检验法建立了偏最小二乘(PLS)模型,并用所建立的校正模型对独立预测集样本进行了预测。结果表明,当采用二阶导数及变量稳定性的竞争自适应加权抽样法(SCARS)选择的波长对光谱进行处理时,所建立的模型预测效果最佳,在隐变量数为10时,模型相关系数为0.9906,校正均方根误差(RMSEC)为0.0523 g/100 g,预测相关系数Rp=0.9781,预测均方根误差(RMSEP)=0.0577 g/100 g,该模型具有较好的预测能力,可用于香菇多糖含量的近红外光谱快速检测。     

绿豆主要营养品质近红外预测模型的构建与验证

运用近红外法预测了中国绿豆主要营养品质蛋白质、淀粉和直链淀粉含量并比较绿豆粉和籽粒两种不同样品类型的差异。102份来自绿豆核心样品为试验材料,采用近红外分析系统扫描了绿豆籽粒和粉样品。光谱数据经预处理后,构建了最小二乘回归预测和交互验证模型并获得了最优校正统计参数。绿豆粉样品最大R2值和最小SECV值蛋白质含量为0.95和0.329,淀粉含量0.90和0.576,直链淀粉含量0.89和0.307;RPD值3.08至4.61。籽粒样品最大R2值和最小SECV值蛋白质含量为0.90和0.404,淀粉含量0.88和0.643,直链淀粉含量0.85和0.426;RPD值2.51至3.23。模型的稳健性采用外部验证法进行了评价。豆粉样品的平均差异1.0%～1.8%比籽粒样品略低。结果表明绿豆粉的三种组分的近红外预测方法具有快速和简单的特点,可应用于绿豆品质的测定。籽粒样品还具有无损种子结构,保持种子活力的特点,可在育种、种质资源创新等方面应用,但其准确度还有待进一步的改善。     

小波分析在人血清中葡萄糖短波近红外定量中的应用

利用小波分析对13名志愿者18个血清样品的短波近红外光谱进行去噪预处理,以血糖仪测定的血糖为参考,采用间隔偏最小二乘法（iPLS）在700nm～1060nm短波近红外波段建立血糖浓度预测模型。由相关系数（R）和预测标准差（RMSEP）对预测模型的精确度进行了评价。预测模型的相关系数为0．9654,均方根预测误差为0．2435,并和采用傅立叶变换去噪方法及iPLS建模的结果进行了比较。结果表明：小波分析预处理数据的方法能更有效地扣除噪声干扰,使模型具有更强的抗干扰能力和更高的预测精度。     

近红外光谱测定小麦粉常规营养成分的模型优化

目的：应用近红外光谱（NIR）结合偏最小二乘法（PLS）建立小麦粉常规营养成分蛋白质、水分和脂肪的含量预测模型,并选择最佳模型。方法：收集117份小麦粉样品的近红外光谱,化学法测定蛋白质、水分和脂肪的含量,利用主成分分析（PCA）随机分组,81份样品用于构建模型、36份样品用作验证模型的预测能力。探讨波长范围和光谱预处理方法对所建模型预测能力的影响。结果：3个营养成分预测能力最好的模型分别是：对于蛋白质,预处理采用矢量归一化（SNV）,波长选取7 505.9~5 446.2 cm-1和4 605.4~4 242.8 cm-1,预测模型的RPD值是7.02;对于水分,无预处理,波长选择全谱12 800~3 960 cm-1,模型的RPD值是6.83;对于脂肪,无预处理,波长在9 000~4 000 cm-1,模型的RPD值是5.06。结论：近红外光谱法可以实现对小麦粉常规营养成分的快速预测,通过选择波长范围和光谱预处理方法可以显著提高模型的预测能力。     

近红外漫反射光谱法快速测定药用植物淫羊藿总黄酮含量

利用一种基于近红外漫反射光谱技术的淫羊藿总黄酮快速定量分析方法, 测定了淫羊藿属(Epimedium)7个种中总黄酮的含量。研究结果表明, 近红外光谱经二阶导数处理、主成分分析聚类及加权多元离散校正处理后, 采用改进最小二乘法回归得到的定标模型的预测效果最佳; 定标样品集预测方程的定标决定系数、交互验证标准差及交互验证相关系数分别为0.985 5、0.023 0和0.044 3; 检验样品集方程的定标决定系数、检验标准差及偏差分别为0.965 1、0.018和0.006, 达到了快速测定淫羊藿总黄酮含量的要求。该方法为淫羊藿总黄酮的快速定量分析提供了新的依据。     

NIRS结合TQ软件快速测定山茱萸中莫诺苷的含量北大核心CSCD

应用近红外光谱法对山茱萸中莫诺苷的含量进行快速测定。利用高效液相色谱法测定山茱萸药材中莫诺苷的含量,采用偏最小二乘法建立其含量与近红外光谱之间的模型,并对未知样品进行含量测定。所建莫诺苷的定量模型的相关系数(R2)为0.9857,校正均方差(RMSEC)、内部交叉验证均方差(RMSECV)和预测均方差(RMSEP)分别为0.105、0.2738和0.234。结果表明该方法所测结果准确,且不需复杂的前处理、绿色、无损,适用大批量山茱萸中莫诺苷的快速测定。     

NIRS结合TQ软件快速测定山茱萸中莫诺苷的含量

应用近红外光谱法对山茱萸中莫诺苷的含量进行快速测定。利用高效液相色谱法测定山茱萸药材中莫诺苷的含量,采用偏最小二乘法建立其含量与近红外光谱之间的模型,并对未知样品进行含量测定。所建莫诺苷的定量模型的相关系数(R2)为0.9857,校正均方差(RMSEC)、内部交叉验证均方差(RMSECV)和预测均方差(RMSEP)分别为0.105、0.2738和0.234。结果表明该方法所测结果准确,且不需复杂的前处理、绿色、无损,适用大批量山茱萸中莫诺苷的快速测定。     

傅里叶变换中红外光谱结合偏最小二乘法快速测定蕨菜总多糖含量CSCD

本文建立了一种快速预测蕨菜总多糖含量的方法。采用蒽酮-硫酸比色法测定140份蕨菜总多糖含量作为参比值,采集140份蕨菜样品的傅里叶变换中红外光谱图,结合偏最小二乘法,建立蕨菜总多糖定量分析模型。通过比较多元散射校正法、标准正态变换法、一阶导数法、二阶导数法、多元散射校正+一阶导数法、标准正态变换+一阶导数法、多元散射校正+二阶导数法以及标准正态变换+二阶导数法共8种不同的光谱预处理方法,运用多糖类化合物的中红外光谱学特征吸收筛选建模波段,对蕨菜多糖含量预测模型进行优化。结果表明:采用标准正态变换法作为光谱数据预处理方法,以1750~1600、1500~1400、1350~1290、1160~1070、1060~970、930~800 cm^(-1)作为建模波段,获得校正集相关性系数R^(2)为0.9308,校正均方差(RMSEC)为0.374%,检验集相关性系数R^(2)为0.9145,预测均方差(RMSEP)为0.418%,20组样品进行完全外部验证误差为:-0.35%~0.31%,相对误差值为:-0.83%~5.24%,所构建定量模型可用于蕨菜总多糖含量预测。     

近红外光谱法快速测定木香中木香烃内酯与去氢木香内酯的含量

本文主要研究近红外光谱法在快速测定木香药材中木香烃内酯与去氢木香内酯含量的应用。采用近红外漫反射光谱法采集木香的近红外光谱,以HPLC测量值为参考值,运用偏最小二乘法(PLS)建立木香烃内酯与去氢木香内酯含量的定量模型,并用未知样品验证该模型。结果表明所建定量模型的校正集内部交叉验证相关系数(R2)、校正均方差(RMSEC)和内部交叉验证均方差(RMSECV)分别为0.9783、0.161和0.374;经外部验证的预测相关系数(r2)和预测均方差(RMSEP)分别为0.9546和0.162。该方法操作简便,测定快速,结果准确,无污染,可用于木香药材中木香烃内酯与去氢木香内酯含量的快速测定。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.