Formation of silicon-on-insulator layers by electron beam recrystallization

This paper outlines the development of the electron beam recrystallization approach to the formation of silicon-on-insulator layers. The technique of recrystallizing seeded layers by a line electron beam has been widely adopted. Present practice in electron beam recrystallization is reviewed, both from materials and process points of view. Applications of silicon-on-insulator substrates formed in this way are described, particularly in three-dimensional integration. © 1988.

A new, fast response CO2 sensor

The inability of emissions reduction methods to meet upcoming legislation without an unacceptable increase in vehicle cost is a major problem of automobile manufacturer. This work aims to develop a cost-effective reduction of automobile emissions. A prototype CO2 sensor with 5 msec response time was built and bench tested, then used on an engine. The sensor design was based on standard emissions measurement technology using non-dispersive IR absorption. An improved sensor has now been completed with significant improvements in terms of signal to noise ratio and long-term stability. The improved sensor will be used to measure CO2 concentrations on three different engines. The results will then be used to validate engine and catalyst models and to propose control strategies aimed at reducing overall emissions. A brief description of the sensor itself was presented. Original is an abstract.

Construction of a BAC library for Chinese amphioxus Branchiostoma belcheri and identification of clones containing Amphi-pax genes

Amphioxus is a crucial organism for the study of vertebrate evolution. Although a genomic BAC library of Branchiostoma floridae has been constructed, we report here another BAC library construction of its distant relative species Branchiostoma belcheri. The amphioxus BAC library established in present study consists of 45,312 clones arrayed in one hundred and eighteen 384-well plates. The average insert fragment size was 120 kb estimated by Pulsed Field Gel Electrophoresis (PFGE) analysis of 318 randomly selected clones. The representation of the library is about 12 equivalent to the genome, allowing a 99.9995% probability of recovering any specific sequence of interest. We further screened the library with 4 single copied Amphi-Pax genes and identified total of 26 positive clones with average of 6.5 clones for each gene. The result indicates this library is well suited for many applications and should also serve as a useful complemental resource for the scientific community.

Assessment of cattle genetic introgression into domestic yak populations using mitochondrial and microsatellite DNA markers

Hybridization between yak Poephagus grunniens and taurine Bos taurus or indicine B. indicus cattle has been widely practiced throughout the yak geographical range, and gene flow is expected to have occurred between these species. To assess the impact of cattle admixture on domestic yak, we examined 1076 domestic yak from 29 populations collected in China, Bhutan, Nepal, India, Pakistan, Kyrgyzstan, Mongolia and Russia using mitochondrial DNA and 17 autosomal microsatellite loci. A cattle diagnostic marker-based analysis reveals cattle-specific mtDNA and/or autosomal microsatellite allele introgression in 127 yak individuals from 22 populations. The mean level of cattle admixture across the populations, calculated using allelic information at 17 autosomal microsatellite loci, remains relatively low (mY(cattle) = 2.66 +/- 0.53% and Q(cattle) = 0.69 +/- 2.58%), although it varies a lot across populations as well as among individuals within population. Although the level of cattle admixture shows a clear geographical structure, with higher levels of admixture in the Qinghai-Tibetan Plateau and Mongolian and Russian regions, and lower levels in the Himalayan and Pamir Plateau region, our results indicate that the level of cattle admixture is not significantly correlated with the altitude across geographical regions as well as within geographical region. Although yak-cattle hybridization is primarily driven to produce F-1 hybrids, our results show that the subsequent gene flow between yak and cattle took place and has affected contemporary genetic make-up of domestic yak. To protect yak genetic integrity, hybridization between yak and cattle should be tightly controlled.

An empirical study on income and efficiency of pond fish and nursery fish production in some selected areas of Pabna, Bangladesh

The study was designed to determine the costs, returns and relative profitability of pond fish and nursery fish production. In order to attain this objective, a total of 70 producers: 35 producing pond fish and 35 producing nursery fish were selected on the basis of purposive random sampling technique from 6 villages under two Upazilas (Sujanagar and Santhia) of Pabna district. It was estimated that per hectare per year gross cost of pond fish production was Tk 65,918 while gross return and net return were Tk 91,707 and Tk 25,789 respectively. Per hectare per year gross cost of nursery fish production was Tk 87,489 while gross return and net return were Tk 1,39,272 and Tk 51,783 respectively. The findings revealed that nursery fish production was more profitable than pond fish production. Cobb-Douglas production function was applied to realize the specific effect of the factors on pond fish and nursery fish production. It was observed that most of the included variables had significant impact on pond fish and nursery fish production. Out of five variables included in the function, all the variables had positive impact on return from pond fish production but stock value of pond, material cost and pond area had positive impact on return from nursery fish production.

Gaussian mixture modeling with Gaussian process latent variable models

Density modeling is notoriously difficult for high dimensional data. One approach to the problem is to search for a lower dimensional manifold which captures the main characteristics of the data. Recently, the Gaussian Process Latent Variable Model (GPLVM) has successfully been used to find low dimensional manifolds in a variety of complex data. The GPLVM consists of a set of points in a low dimensional latent space, and a stochastic map to the observed space. We show how it can be interpreted as a density model in the observed space. However, the GPLVM is not trained as a density model and therefore yields bad density estimates. We propose a new training strategy and obtain improved generalisation performance and better density estimates in comparative evaluations on several benchmark data sets. © 2010 Springer-Verlag.

Trimeresurus stejnegeri snake venom plasminogen activator - Site-directed mutagenesis and molecular modeling

The specific plasminogen activator from Trimeresurus stejnegeri venom (TSV-PA) is a serine proteinase presenting 23% sequence identity with the proteinase domain of tissue type plasminogen activator, and 63% with batroxobin, a fibrinogen clotting enzyme from Bothrops atrox venom that does not activate plasminogen. TSV-PA contains six disulfide bonds and has been successfully overexpressed in Escherichia coli (Zhang, Y., Wisner, A., Xiong, Y. L,, and Bon, C, (1995) J. Biol. Chem. 270, 10246-10255), To identify the functional domains of TSV-PA, we focused on three short peptide fragments of TSV-PA showing important sequence differences with batroxobin and other venom serine proteinases. Molecular modeling shows that these sequences are located in surface loop regions, one of which is next to the catalytic site, When these sequences were replaced in TSV-PA by the equivalent batroxobin residues none generated either fibrinogen-clotting or direct fibrinogenolytic activity, Two of the replacements had little effect in general and are not critical to the specificity of TSV-PA for plasminogen. Nevertheless, the third replacement, produced by the conversion of the sequence DDE 96a-98 to NVI, significantly increased the K-m for some tripeptide chromogenic substrates and resulted in undetectable plasminogen activation, indicating the key role that the sequence plays in substrate recognition by the enzyme.

无指盘臭蛙皮肤活性肽及其基因和在制药中的应用

本发明涉及一种无指盘臭蛙皮肤活性肽及及其基因和在制药中的应用，属于生物医学领域。无指盘臭蛙皮肤活性肽是无指盘臭蛙皮肤活性肽基因编码的一种单链多肽，分子量3015.63道尔顿，等电点10.3，多肽全序列一级结构为： Ala Thr Ala Leu Gly Leu Ser Ser Arg Gly Leu Leu Pro Ile Gly Phe Met Phe Lys Asp Thr Ile Arg Cys Arg Lys Tyr(ATALGLSSRGLLPIGFMFKDTIRCRKY)。编码无指盘臭蛙皮肤活性肽的基因由312个核苷酸组成，其中编码成熟无指盘臭蛙皮肤活性肽为第141-222位核苷酸。人工合成的无指盘臭蛙皮肤活性肽具有很强的抑制细菌和真菌生长的作用，可以作为制备病原微生物感染疾病的治疗药物被应用。无指盘臭蛙皮肤活性肽具有结构简单、人工合成方便、抗菌谱系广、抗菌活性强的特点。

无指盘臭蛙臭蛙肽及其基因和在制药中的应用

本发明涉及一种无指盘臭蛙臭蛙肽及其基因和在制药中的应用，属于生物医学领域。无指盘臭蛙臭蛙肽是无指盘臭蛙臭蛙肽基因编码的一种单链多肽，分子量1814.11道尔顿，等电点8.08，多肽全序列一级结构为： Gly Cys Ser Arg Trp Ile Ile Gly Ile His Gly Gln Ile Cys Arg Asp。(GCSRWIIGIHGQICRD)。编码无指盘臭蛙臭蛙肽的基因由312个核苷酸组成，其中编码成熟无指盘臭蛙臭蛙肽为第141-189位核苷酸。人工合成的无指盘臭蛙臭蛙肽具有很强的抑制细菌和真菌生长的作用，可以作为制备病原微生物感染疾病的治疗药物被应用。本发明的无指盘臭蛙臭蛙肽具有结构简单、人工合成方便、抗菌谱系广、抗菌活性强的特点。

梭鱼的分子系统地理学研究——晚更新世西北太平洋边缘海隔离分化及其有限的扩散能力

下载PDF阅读器西北太平洋具有独特的板块特征和地质历史,几个边缘海将亚洲大陆和太平洋隔开.在更新世冰期的低海平面时期,海洋生物群体可能会被隔离在日本海、东海和南海.伴随冰后期海平面的上升,以往的研究认为被隔离在3个边缘海的群体会因为扩散的作用而重新混匀.为了检验该假说,本研究探讨了梭鱼的系统地理格局.采集梭鱼分布范围内9个地点的272个梭鱼个体,分析其线粒体控制区5'端435 bp的片段.共检测到3个不同的单倍型类群,这3个单倍型类群可能是在更新世冰期被隔离在3个边缘海内而产生的分化.这一研究结果与以往的假设相反,3个单倍型类群在地理上的频率分布存在很大差异.分子方差分析和群体多样性指数都表明3个边缘海内的梭鱼群体间存在显著的遗传差异.这些结果表明:与基于生物学特性预期的梭鱼具有较高的扩散能力相反,梭鱼群体空间上的基因交流是很有限的.东海的梭鱼群体间缺乏系统地理格局,这可能是因为末次冰盛期后梭鱼群体发生了近期的栖息地扩张,群体间没有足够的进化时间在迁移-漂变间取得平衡.

双峰驼线粒体DNA地高辛标记探针的制备及其应用

利用地高辛标记技术，对从双峰驼肝脏和肾脏提纯的线粒体ＤＮＡ进行了标记，制成探针，并用它检测了包含于白细胞总ＤＮＡ中的微量线粒体ＤＮＡ。结果表明这一技术完全可以成功地用于微量线粒体ＤＮＡＲＦＬＰ的分析。

Molecular phylogeny of Rhacophoridae (Anura): A framework of taxonomic reassignment of species within the genera Aquixalus, Chiromantis, Rhacophorus, and Philautus

Phylogenetic relationships among representative species of the family Rhacophoridae were investigated based on 2904 bp of sequences from both mitochondrial (12S rRNA, 16S rRNA, the complete t-RNA for valine), and nuclear (tyrosinase, rhodopsin) genes. Max