Mammary epithelial proliferation and estrogen receptor alpha expression in prepubertal heifers: effects of ovariectomy and growth hormone

The objectives of this study were to determine the effects of ovariectomy and growth hormone on mammary epithelial cell proliferation and estrogen receptor alpha (ER alpha) expression within the bovine mammary gland. Two experiments were performed. In the first experiment, eight Holstein heifer calves aged between 1 and 3 mo were ovariectomized, while six calves served as controls. At 6 mo of age, calves were treated with bromodeoxyuridine (BrdU) to label proliferating cells and sacrificed 2 h later. Coinciding with reduced mammary mass (304 +/- 25 vs. 130 +/- 21 g), proliferation of mammary epithelial cells was significantly lower in ovariectomized heifers compared to control heifers (2.24 vs. 0.25%). ER alpha expression was restricted to mammary epithelial cells and was not observed within intra-lobular stroma of parenchymal tissue. The proportion of ER alpha positive cells was significantly higher in ovariectomized heifers than in controls (36.1% +/- 2.2 vs. 46.7% +/- 2.4). In the second experiment, mammary biopsies were taken from five 6-mo-old heifers, immediately preceding and 7 d following a single injection of bovine growth hormone. Mammary epithelial cell proliferation (assessed by incorporation of 3H-thymidine) was increased by growth hormone. The proportion of ER alpha positive mammary epithelial cells was not increased by growth hormone. In conclusion, reduced mammary epithelial cell proliferation following ovariectomy was associated with an increase in ER alpha expression, whereas increased proliferation caused by bovine growth hormone was not associated with changes in the proportion of ER alpha positive cells.     

Effects of spatial and spectral resolution in estimating ecosystem α-diversity by satellite imagery

Remote sensing represents a powerful tool to derive quantitative and qualitative information about ecosystem biodiversity. In particular, since plant species richness is a fundamental indicator of biodiversity at the community and regional scales, attempts were made to predict species richness (spatial heterogeneity) by means of spectral heterogeneity. The possibility of using spectral variance of satellite images for predicting species richness is known as Spectral Variation Hypothesis. However, when using remotely sensed data, researchers are limited to specific scales of investigation. This paper aims to investigate the effects of scale (both as spatial and spectral resolution) when searching for a relation between spectral and spatial (related to plant species richness) heterogeneity, by using satellite data with different spatial and spectral resolution. Species composition was sampled within square plots of 100 m² nested in macroplots of 10,000 m². Spectral heterogeneity of each macroplot was calculated using satellite images with different spatial and spectral resolution: a Quickbird multispectral image (4 bands, spatial resolution of 3 m), an Aster multispectral image (first 9 bands used, spatial resolution of 15 m for bands 1 to 3 and 30 m for bands 4 to 9), an ortho-Landsat ETM+ multispectral image (bands 1 to 5 and band 7 used; spatial resolution, 30 m), a resampled 60 m Landsat ETM+ image.Quickbird image heterogeneity showed a statistically highly significant correlation with species richness (r = 0.69) while coarse resolution images showed contrasting results (r = 0.43, r = 0.67, and r = 0.69 considering the Aster, Landsat ETM+, and the resampled 60 m Landsat ETM+ images respectively). It should be stressed that spectral variability is scene and sensor dependent. Considering coarser spatial resolution images, in such a case even using SWIR Aster bands (i.e. the additional spectral information with respect to Quickbird image) such an image showed a very low power in catching spectral and thus spatial variability with respect to Landsat ETM+ imagery. Obviously coarser resolution data tend to have mixed pixel problems and hence less sensitive to spatial complexity. Thus, one might argue that using a finer pixel dimension should inevitably result in a higher level of detail. On the other hand, the spectral response from different land-cover features (and thus different species) in images with higher spectral resolution should exhibit higher complexity.Spectral Variation Hypothesis could be a basis for improving sampling designs and strategies for species inventory fieldwork. However, researchers must be aware on scale effects when measuring spectral (and thus spatial) heterogeneity and relating it to field data, hence considering the concept of scale not only related to a spatial framework but even to a spectral one.     

An alternative approach to fuzzy control charts: Direct fuzzy approach

The major contribution of fuzzy set theory lies in its capability of representing vague data. Fuzzy logic offers a systematic base to deal with situations, which are ambiguous or not well defined. In the literature, there exist few papers on fuzzy control charts, which use defuzziffication methods in the early steps of their algorithms. The use of defuzziffication methods in the early steps of the algorithm makes it too similar to the classical analysis. Linguistic data in those works are transformed into numeric values before control limits are calculated. Thus both control limits as well as sample values become numeric. In this paper, some contributions to fuzzy control charts based on fuzzy transformation methods are made by the use of α-cut to provide the ability of determining the tightness of the inspection: the higher the value of α the tighter inspection. A new alternative approach “Direct Fuzzy Approach (DFA)” is also developed in this paper. In contrast to the existing fuzzy control charts, the proposed approach is quite different in the sense it does not require the use of the defuzziffication. This prevents the loss of information included by the samples. It directly compares the linguistic data in fuzzy space without making any transformation. We use some numeric examples to illustrate the performance of the method and interpret its results.     

芦丁鼠李糖苷酶基因在巴斯德毕赤酵母中的表达

芦丁鼠李糖苷酶目的基因亚克隆至pPIC9K表达载体,电转化至毕赤酵母GS115中,进行了基因表达研究.结果表明,该转化宿主菌在甲醇诱导培养至144 h,表达产蛋白具有芦丁鼠李糖苷酶活性,运用SDS-PAGE电泳技术确定其分子质量为53 ku,与理论值基本相符.     

基于散列辞典的蛋白质二级结构预测方法

提出一种易于修改的蛋白质二级结构预测算法。以蛋白质数据银行中PDB文本数据作为数据源,提取所有蛋白质氨基酸序列并以此建立样本数据库,然后针对α-螺旋、β-折叠分别利用基于散列辞典的不同改进方法编程实现蛋白质二级结构序列片段预测,在预测过程中,随机抽取68421个蛋白质中部分样本作为测试集,对未知序列根据建立的散列辞典中的片段使用正向最大匹配分词法进行切分对比。从实验结果来看,对未知序列片段预测的准确度达到了83．9％,而且能够较好地体现片段之间的连接顺序。     

Electrical Current Signatures of DNA Base Modifications in Single Molecules Immobilized in the α-Hemolysin Ion Channel

Nanopore technology holds high potential for next-generation DNA sequencing. This method operates by drawing an individual single-stranded DNA molecule through a nanoscale pore, while monitoring the current deflections that occur as the DNA passes through. Individual current levels for the four DNA nucleotides have been established by immobilization of an end biotinylated strand in the pore, in which the nucleotide of interest is suspended at the most sensitive region of the ion channel. Due to the inherent reactivity of DNA bases, many modified nucleotides in the genome exist as a result of oxidative and UV insults, among others. Herein, the current levels for common DNA damage lesions 8-oxo-7,8-dihydroguanine, spiroiminodihydantoin, guanidinohydantoin, uridine, abasic sites, thymine dimers, thymine glycol, and 5-iodocytosine were assessed through immobilization experiments. In some cases, the current difference between the damaged and canonical nucleotides was not well resolved; therefore, we took advantage of the chemical reactivity of the new functional groups present to make amine adducts that shifted the current levels outside the range of the native nucleotides. Among the adducts studied, only the 2-aminomethyl-18-crown-6 adduct was able to give a large current shift in the immobilization experiment, as well as being observed in a translocation experiment. The results show potential in providing current-level modulators for identification of some types of DNA damage. In principle, any DNA base modification that can be converted chemically or enzymatically into an abasic site could be identified in this way.     

铁粉还原应用于α-卤代羰基化合物的卤素消除研究

对铁粉还原应用于α-卤代羰基化合物的卤素消除进行了研究,实验证明,铁粉不仅可用于4-溴-2-氯-2-甲基-卜茚酮的脱氯反应,也可用于2,4-二溴-5-甲氧基-6-叔丁基-2-甲基-l-茚酮的脱溴反应,并且经过了工业化验证,给出了工业化放大时的建议.     

Quantitative measurement of oxygen content in Si targets

Enriched self-supporting targets of ^28,29,30Si are often used in the field of high resolution nuclear physics experiments. The Si targets were prepared by the thermal evaporation deposition or reduction-deposition methods. The targets, however, are always contaminated by oxygen as Si-material is easily oxidised. These contaminated targets lead to poor data with low S/N ratio. Thus it is very useful if one can estimate the amount of oxygen in the target quantitatively before experiments.In this work we have developed a method to estimate the amount of oxygen in the Si target. We used α-ray and β-ray thickness gauges, which have different sensitivity to oxygen atoms. Namely, the α-ray gauge is more sensitive to light elements such as oxygen compared to the β-ray gauge. Thus one can deduce the amount of oxygen by comparing the oxygen thickness measured by α-ray gauge with that of the β-ray gauge.Accuracy of a few percents can be obtained for the oxygen content in Si targets with a thickness of 1 mg/cm². The present method can also be applied to heavy elements such as Ta₂O₅.     

A Review on Structure–Activity Relationship of Dietary Polyphenols Inhibiting α-Amylase

The inhibitory effects of dietary polyphenols against α-amylase have attracted great interest among researchers. The aim of this review is to give an overview of the research reports on the structure–activity relationship of polyphenols inhibiting α-amylase. The molecular structures that influence the inhibition are the following: (1) The hydroxylation of flavonoids improved the inhibitory effect on α-amylase; (2) Presence of an unsaturated 2,3-bond in conjugation with a 4-carbonyl group has been associated with stronger inhibition; (3) The glycosylation of flavonoids decreased the inhibitory effect on α-amylase depending on the conjugation site and the class of sugar moiety; (4) The methylation and methoxylation of flavonoids obviously weakened the inhibitory effect; (5) The galloylated catechins have higher inhibition than nongalloylated catechins; the catechol-type catechins were stronger than the pyrogallol-type catechins; the inhibition activities of the catechins with 2,3-trans structure were higher than those of the catechins with 2,3-cis structure; (6) Cyanidin-3-glucoside showed higher inhibition against than cyanidin and cyanidin-3-galactoside and cyanidin-3,5-diglucoside had no inhibitory activity; (7) Ellagitannins with β-galloyl groups at glucose C-1 positions have higher inhibitory effect than the α-galloyl and nongalloyl compounds and the molecular weight of ellagitannins is not an important element.     

织物用聚醚改性氨基硅油柔软剂的合成

以α,ω-二羟基聚二甲基硅氧烷(WS-62M)、N-β-氨乙基-γ-氨丙基三甲氧基硅烷(SG-Si900)和聚氧乙烯甲基缩水甘油醚(GPOME)为原料,经酯交换和开环反应合成了可用于织物柔软整理的聚醚改性氨基硅油,用它整理后的织物具有柔软的手感、较好的白度和吸水性。氨基硅油的最佳合成条件:n(WS-62M)/n(SG-Si900)=1.33:1,ω(三乙胺)=1.53%,反应温度120℃,反应时间10 h,在0.01 MPa 条件下抽真空0.5～1h。聚醚改性氨基硅油的最佳合成条件:n(GPOME)/n(氨基硅油)=7.2:1,m(异丙醇)/m(GPOME+氨基硅油)=1:1,反应温度80℃,反应时间5 h。