Molecular cloning and characterization of a thioester-containing protein from Zhikong scallop Chlamys farreri

Thioester-containing proteins are a family of proteins characterized by the unique intrachain beta-cysteinyl-gamma-glutamyl thioester, which play important roles in innate immune responses. The cDNA of Zhikong scallop Chlamys farreri thioester-containing protein (designated as CfTEP) was cloned by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of CfTEP was of 4616 bp, consisting of a 5 '-terminal untranslated region (UTR) of 30 bp and a 3 ' UTR of 140 bp with a polyadenylation signal sequence AATAAA and a poly(A) tail. The CfTEP cDNA encoded a polypeptide of 1481 amino acids with the theoretical isoelectric point of 5.98 and the predicted molecular weight of 161.4 kDa. The deduced amino acid sequence of CfTEP contained the canonical thioester motif GCGEQ, nine potential N-glycosylation sites and a C-terminal distinctive cysteine signature. It also contained a presumed catalytic histidine and proteolytic cleavage sites that were similar to C3 molecules. The high similarity of CfTEP with the thioester-containing proteins in other organisms, such as the TEPs from insects, the complement component C3, C4, C5 and the protease inhibitor alpha(2)-macroglobulin indicated that CfTEP should be a member of TEP family. The phylogenetic analysis revealed that CfTEP was closely related to TEPs from mollusc, nematodes and insects, and they formed a separate branch apart from the branches of complements factors and alpha(2)-macroglobulins. The spatial expression of CfTEP transcripts in healthy and bacterial challenged scallops was examined by semi-quantitative RT-PCR. The CfTEP transcripts were mainly detected in the tissues of hepatopancreas and gonad, and remarkably up-regulated by Microbial challenge, which suggested that CfTEP was a constitutive and inducible acute-phase protein involved in immune defense. These results provided new insights into the role of CfTEP in scallop immune responses, as well as the evolutionary origin of this important, widespread and functionally diversified family of proteins. (c) 2007 Published by Elsevier Ltd.

扇贝裙多肽的制备与分析

海洋生物是新型的肽类次级代谢物的丰富来源，现已从多种生物中发现一系列高活性的抗肿瘤、抗病毒、抗微生物及心血管疾病的活性多肽。以栉孔扇贝裙为原料，利用酶解的方法制备肽混合物，对其进行分离分析，获得高附加值的混合肽制品。通过一系列酶反应动力学研究，进行最佳用酶及其酶解最佳条件的选择。酶解条件为：酶浓度2500单位/每克样品，酶解温度45 ℃， 使用537酸性蛋白酶和1398中性蛋白酶先后于pH3和pH7左右作用共计5个小时。对所得胨肽混合物进行超滤，分级纯化，选择分子量介于600与4000道尔顿之间的混合肽，测定其氨基酸的组成，含有18种氨基酸，其中天门冬氨酸、谷氨酸、甘氨酸含量最高。通过SDS-PAGE对主要成分进行分离并确定分子量大小，电泳结果显示：混合肽主要含有三至五种多肽成分，分子量介于1000至3000道尔顿之间。通过质谱分析得到验证，并确定五种多肽的分子量分别为1714.32、 1857.97、 2034.53、 2474.77、 2492.80道尔顿。

黄海夏季温度分布及相关现象的数值研究

本论文应用数值方法, 对夏季黄海的温度分布状况及其相关的现象,如黄海冷水团、潮汐锋、温跃层以及溶解氧垂直分布最大值等进行了研究.第二章，用一个二维断面模式，模拟增温期（从4月到8月）黄海潮汐锋的形成和演化过程，对南黄海和北黄海的5条主要断面进行了后报试验。将表层和底层温度、跃层深度、潮汐锋位置等的后报结果与实测结果相比较可以看出：结果是令人满意的。就温度随断面分布及层化现象随时间的变化趋势来看，计算与实测表现出较好的一致性。各断面表、底层温度平均预报合格率及潮汐锋位置预报总成功率都很高。说明本模式是成功的，可以用于黄海潮水汐锋的数值预报.溶解氧不但是海洋调查的主要内容之一也是一个非常重要的水文要素。我国许多学者对黄海溶解氧垂直分布最大值进行了研究，指出夏季黄海溶解氧的分布状况主要由水温控制，溶解氧的分布与水温分布密切相关，但我国在此方面的数值研究工作尚属空白。在第二章工作基础上，第三章建立了一个二维断面溶解氧的数值模式，模拟了夏季黄海溶解氧垂直分布最大值的形成和演化过程，并对影响溶解氧生垂直分布状况的三种主要过程：即垂直涡动混合、生物活动和海气界面的气体交换进行了数值试验和讨论。结果表明，在增温期，由于温跃层的形成和存在，限制了垂直方向的交换，使跃层下界附近的溶解氧得以保留，同时上层海气交换和下层有机物分解耗氧，从而在跃层附近形成最大值；由于黄海海区的跃层一般都在真光层以内因此浮沲植物的光合作用产氧可以增加跃层附近氧的含量，进而影响最大值的大小但对是否开成最大值影响不大；上混合层中的生物产氧大都通过海气界面的气体交换进入大气。海气界面的气体交换速度可以影响上混合层的溶解氧浓度，但对溶解氧最大值影响很小。夏季黄海的温度分布明显具有三维特征，在前面二维数值工作的基础上，第四章又进一步作了三维数值研究。在诸多三维数值模式中，普林斯顿海洋模式（POM）在国外应用最为广泛。第四章首先简单介绍了POM模式，然后模拟了黄海的潮汐和潮流，给出了潮汐和潮海的一些主要特征，包括无潮点、等振幅线和同潮时线、潮流分布等。最后将POM模式应用于黄海，以黄海温度的垂直均匀分布（4月）状态为初值，考虑海面热交换、风应力和潮的作用，对黄海的温度结构进行了数值模拟，基本上再现了黄海冷水团、潮汐锋和温跃层的形成和演化过程。模拟结果显示：由于太阳辐射，原本垂直混合均匀的海水开始层化：由于风的涡动混合作用，上层海水混合均匀，形成上混合层：下层海水则由于潮水的混合作用而混合均匀。这样，在深水区形成了温跃层；在浅区和深海区之间等温线密集，从而形成了温度锋。在整个增温期，底层冷水得以保存，温跃层则不断增强.

Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas

Ligularia, a highly diversified genus in the eastern Qinghai-Tibet Plateau and adjacent areas, was chosen as a suitable subject in which to study speciation patterns in this 'hot spot' area at the chromosomal level. Chromosome numbers and karyotypes were studied in 23 populations of 14 species, most of which are endemic to this area. The basic number x = 29 was confirmed for all species. Ligularia virgaurea was found to have diploid and triploid cytotypes, 2n = 58 and 87. Other species are only diploid, with 2n = 58. The karyotypes of all populations within any species, and all species spanning most sections and covering most of the morphological range in Ligularia, are very similar to each other, belonging to type 2A according to Stebbin's classification. This karyotype was also found in its close allies, e.g. Cremanthodium, Ligulariopsis, Parasenecio, and Sinacalia. Aneuploid reduction of chromosome number from 2n = 60 to 58 and karyotypic variation was found in Ligularia and its allies. Such a chromosomal pattern with few polyploids infers that variation of karyotype structure at the diploid level seems to be the predominant feature of chromosomal evolution in this group and sympatric speciation via hybridization and polyploidization has played a minor role in its species diversity. (C) 2004 The Linnean Society of London

敏捷制造:高技术产业化之路

“敏捷制造”是指企业能抓住瞬息即逝的机遇，快速推出高性能、高可靠性及顾客能接受的价格的新产品的能力。在敏捷制造企业中，有创新能力和经验的员工是企业的主要财富。敏捷制造为高新技术产业化开拓了生产规模与市场规模开拓同步增长的可行道路，又在企业与用户之间建立起崭新的“战略”依存关系。

长白山火山成因—物理机制和化学演化

This thesis is one of the contributions to NSFC project, “The Changbaishan Volcanism and its Links to the Northeast Asia Tectonic System”. The thesis presents our most recent works on Changbaishan Volcanism, on two aspects as (1) the chemical evolution of the Cenozoic volcanism and the physical links of magma genesis, (2) the Holocene activity of the Tianchi Volcano and risks of potential eruption. 1. Chemical evolution and physical links to the Changbaishan Volcanism Physical links to the Chanbaishan Volcanism, just like origins of most of the volcanisms in eastern China, has long been an enigma. A large scale of volcanic activity has dominated many places of eastern China in Meso-Cenozoic. Activity of these volcanisms in eastern China covers several quite different blocks, covers variety of tectonics, and covers a period of time over 200 million years. Such a large-scale and long-lived volcanism in a continental area challenges our knowledge on dynamics of the Earth’s interior. Some works on “Diwa” hypothesis and “lithospheric thinning” hypothesis present possible links between volcanisms and dynamic evolutions of the earth’s interior, but still cannot interpret where are the sources of the heat and fluid, which are essential to the volcanisms. Based on the study of this thesis, we suggest that dynamics of the deep subduction of western Pacific Plate is the critical factor to the Changbaishan Volcanism and volcanisms in NE China, and maybe even essential to most of the Meso-Cenozoic volcanisms in eastern China. In NE China, stagnant slabs flatted in the mantle transition zone (MTZ, ca. 660 km deep) transport and release significant hydrous fluid to the upper mantle. Metamorphism of the deep-subducted slabs and hence a series of mineral phases play an important role in the water transport, exchange, restore, and release. Dehydrated fluid of the wet slab ascending from the MTZ fertile the upper mantle, and also provide upward heat flow which is essential to the magma genesis. Then magma and volcanism occur with the deep subduction from Mesozoic to mordern time in eastern China. To discribe the exact chemical characteristics of the deep subduction releated volcanics is very difficult, because few researches has contributed to the chemical behaviors of fluid and trace elments in the very deep interior of the Earth, such 660 km deep, 410km or 350km where the fluid may ascend and react. However we can still find some chemical characteristics of oceanic subduction. Basalts of the Changbaishan Volcanism have siginficant characteristics of potassium rich, and even can be called a potassic igneous province. If there are only two possible ways, recycled continentical crust or oceanic crust, to fertile the mantle potossium element as we know now, it’s easy to attribute this to the deep-subducted of the west Pacific Plate. To the eastern China, fluid inclusions in mantle xenoliths from the Cenozic basalts also reveal potassium-rich characteristics. This reveals that the same potassium feritle agents may occur in the mantle sources of eastern China. 2. Holocene activiy of the Tianchi Volcano As one of the large volcanic center and complex volcanic cone, the Tianchi Volcano is a dangerous active volcano, with several Holocene eruptions. Among these eruptions, the Millennium Eruption is regardede as one of the biggist eruptions in the world in the last 2000 years. To estimate the potential danger of volcanic eruption, we discuss two essential factors, as (i) volcanic history of Holocene eruptions, including volcanic geolgy, chronnology and chemistry, (ii) state, evolution and relationship of the magma chambers in mantle and crust beneath the Tianchi Volcano.

乌鲁木齐河源1号冰川表层雪的化学特征——以低分子有机酸和无机阴离子为例

表层雪是联系大气成分与冰芯记录的重要纽带,是研究成冰作用过程中化学组成变化的起点.为配合天山乌鲁木齐河源1号冰川成冰作用过程中化学组成变化的研究,对1号冰川积累区(海拔4130 m)一个完整年度的表层雪样品进行了低分子有机酸和无机阴离子含量的分析.结果显示:表层雪中低分子有机酸主要有HCOO-、CH3COO-、C2H5COO-和(COO)22-,无机阴离子主要有F-、Cl-、NO2-、NO3-、SO42-和PO43-.除(COO)22-外,大部分高浓度的有机酸…

Levantamento semidetalhado dos solos e avaliação da aptidão agrícola das terras da Microbacia do Córrego da Cachoeira, Município de Paty do Alferes, RJ.

2000

Contribuição ao sistema brasileiro de classificação de solos com a inclusão da nomenclatura físico-hídrica nos 5º e 6º níveis categóricos

2004

On-line concentration of proteins in pressurized capillary electrochromatography coupled with electrospray ionization-mass spectrometry

Pressurized capillary electrochromatography (pCEC) and electrospray ionization-mass spectrometry (ESI-MS) have been hyphenated for protein analysis. Taken cytochrome c, lysozyme, and insulin as samples, the limits of detection (LODs) for absolute concentrations are 10(-11) mol (signal-to-noise ratio S/N = 3) with relative standard deviations (RSDs) of retention time and peak area, respectively, of less than 1.7% and 4.8%. In order to improve the detection sensitivity, on-line concentration by field-enhanced sample-stacking effect and chromatographic zone-sharpening effect has been developed, and parameters affecting separation and detection, such as pH and electrolyte concentration in the mobile phase, separation voltage, as well as enrichment voltage and time, have been studied systematically. Under the optimized conditions, the LODs of the three proteins could be decreased up to 100-fold. In addition, the feasibility of such techniques has been further demonstrated by the analysis of modified insulins at a concentration of 20 mu g/mL.

Quantum Flows as Markovian Limit of Emission, Absorption and Scattering Interactions

Gough, John, (2004) 'Quantum Flows as Markovian Limit of Emission, Absorption and Scattering Interactions', Communications in Mathematical Physics 254 pp.498-512 RAE2008

Services to support BU Authors with Open Access Issues

A working paper written for Boston University Libraries to foster discussion about how to provide better support for BU faculty authors.

Timeliness via Speculation for Real-Time Databases

Various concurrency control algorithms differ in the time when conflicts are detected, and in the way they are resolved. In that respect, the Pessimistic and Optimistic Concurrency Control (PCC and OCC) alternatives represent two extremes. PCC locking protocols detect conflicts as soon as they occur and resolve them using blocking. OCC protocols detect conflicts at transaction commit time and resolve them using rollbacks (restarts). For real-time databases, blockages and rollbacks are hazards that increase the likelihood of transactions missing their deadlines. We propose a Speculative Concurrency Control (SCC) technique that minimizes the impact of blockages and rollbacks. SCC relies on the use of added system resources to speculate on potential serialization orders and to ensure that if such serialization orders materialize, the hazards of blockages and roll-backs are minimized. We present a number of SCC-based algorithms that differ in the level of speculation they introduce, and the amount of system resources (mainly memory) they require. We show the performance gains (in terms of number of satisfied timing constraints) to be expected when a representative SCC algorithm (SCC-2S) is adopted.

Fast Shortest Path Distance Estimation in Large Networks

We study the problem of preprocessing a large graph so that point-to-point shortest-path queries can be answered very fast. Computing shortest paths is a well studied problem, but exact algorithms do not scale to huge graphs encountered on the web, social networks, and other applications. In this paper we focus on approximate methods for distance estimation, in particular using landmark-based distance indexing. This approach involves selecting a subset of nodes as landmarks and computing (offline) the distances from each node in the graph to those landmarks. At runtime, when the distance between a pair of nodes is needed, we can estimate it quickly by combining the precomputed distances of the two nodes to the landmarks. We prove that selecting the optimal set of landmarks is an NP-hard problem, and thus heuristic solutions need to be employed. Given a budget of memory for the index, which translates directly into a budget of landmarks, different landmark selection strategies can yield dramatically different results in terms of accuracy. A number of simple methods that scale well to large graphs are therefore developed and experimentally compared. The simplest methods choose central nodes of the graph, while the more elaborate ones select central nodes that are also far away from one another. The efficiency of the suggested techniques is tested experimentally using five different real world graphs with millions of edges; for a given accuracy, they require as much as 250 times less space than the current approach in the literature which considers selecting landmarks at random. Finally, we study applications of our method in two problems arising naturally in large-scale networks, namely, social search and community detection.

Nearest-neighbor Queries in Probabilistic Graphs

Large probabilistic graphs arise in various domains spanning from social networks to biological and communication networks. An important query in these graphs is the k nearest-neighbor query, which involves finding and reporting the k closest nodes to a specific node. This query assumes the existence of a measure of the "proximity" or the "distance" between any two nodes in the graph. To that end, we propose various novel distance functions that extend well known notions of classical graph theory, such as shortest paths and random walks. We argue that many meaningful distance functions are computationally intractable to compute exactly. Thus, in order to process nearest-neighbor queries, we resort to Monte Carlo sampling and exploit novel graph-transformation ideas and pruning opportunities. In our extensive experimental analysis, we explore the trade-offs of our approximation algorithms and demonstrate that they scale well on real-world probabilistic graphs with tens of millions of edges.