尖吻蝮蛇蛇毒出血毒素DaHT-3的纯化与性质

通过Sephadex G-75,DEAE-Sephadex A-50,Sephadex G-200和两次PBE聚焦层析,从尖吻蝮蛇(Dienagkistrodon acutus)蛇毒中纯化到一个分子量为56 000的出血毒素(DaHT-3),经氨基酸组成测定计算,由487个氨基酸残基组成。此成分在SDS-PAGE上显示出一条均一的蛋白染色带,用等电聚焦电泳测定,其pI为5.50。该出血成分的最小出血剂量是2.6#mu#g,具有蛋白水解酶活力,其活力为3.68,但没有精氨酸酯酶和磷脂酶A_(2)活力。用红外光谱仪研究DaHT-3在溶液中酰胺Ⅰ带的吸收谱,该毒素含有31.8%的#alpha#螺旋、56.1%的#beta#折叠和12.1%的转角;当加入EDTA螯合剂去除金属离子后,它们的#alpha#螺旋、#beta#折叠、转角和无规卷曲分别变为11%、26.4%、46.2%和16.5%,而出血活力和蛋白水解酶活力均丧失,表明该出血毒素是金属蛋白酶。

Case study on a deep excavation in soft ground by centrifuge model tests

This paper provides a case study on the deepest excavation carried out so far in the construction of the metro network in Shanghai, which typically features soft ground. The excavation is 38 m deep with retaining walls 65 m deep braced by 9 levels of concrete props. To obtain a quick and rough prediction, two centrifuge model tests were conducted, in which one is for the 'standard' section with green field surrounding and the other with an adjacent piled building. The tests were carried out in a run-stop-excavation-run style, in which excavation was conducted manually. By analyzing the lateral wall displacement, ground deformation, bending moment and earth pressure, the test results are shown to be reasonably convincing and the design and construction were validated. Such industry orientated centrifuge modeling was shown to be useful in understanding the performance of geotechnical processes, especially when engineers lack relevant field experience. © 2010 Taylor & Francis Group, London.

Concrete column recognition in images and videos

The automated detection of structural elements (e.g., columns and beams) from visual data can be used to facilitate many construction and maintenance applications. The research in this area is under initial investigation. The existing methods solely rely on color and texture information, which makes them unable to identify each structural element if these elements connect each other and are made of the same material. The paper presents a novel method of automated concrete column detection from visual data. The method overcomes the limitation by combining columns’ boundary information with their color and texture cues. It starts from recognizing long vertical lines in an image/video frame through edge detection and Hough transform. The bounding rectangle for each pair of lines is then constructed. When the rectangle resembles the shape of a column and the color and texture contained in the pair of lines are matched with one of the concrete samples in knowledge base, a concrete column surface is assumed to be located. This way, one concrete column in images/videos is detected. The method was tested using real images/videos. The results are compared with the manual detection ones to indicate the method’s validity.

Automated 3D Vision Tracking for Project Control Support

On-site tracking in open construction sites is often difficult because of the large amounts of items that are present and need to be tracked. Additionally, the amounts of occlusions/obstructions present create a highly complex tracking environment. Existing tracking methods are based mainly on Radio Frequency technologies, including Global Positioning Systems (GPS), Radio Frequency Identification (RFID), Bluetooth and Wireless Fidelity (Wi-Fi, Ultra-Wideband, etc). These methods require considerable amounts of pre-processing time since they need to manually deploy tags and keep record of the items they are placed on. In construction sites with numerous entities, tags installation, maintenance and decommissioning become an issue since it increases the cost and time needed to implement these tracking methods. This paper presents a novel method for open site tracking with construction cameras based on machine vision. According to this method, video feed is collected from on site video cameras, and the user selects the entity he wishes to track. The entity is tracked in each video using 2D vision tracking. Epipolar geometry is then used to calculate the depth of the marked area to provide the 3D location of the entity. This method addresses the limitations of radio frequency methods by being unobtrusive and using inexpensive, and easy to deploy equipment. The method has been implemented in a C++ prototype and preliminary results indicate its effectiveness

两种藻类对水体氮、磷去除效果

借助人工装置和露天水池,通过分析实验水体中氮、磷元素浓度的变化,研究了实验室条件下一种绿球藻(Chlorococcumsp.)和露天小型生态系统中寡枝刚毛藻(Cladophora oligoclonaKütz).对污水中氮磷营养的去除效果.结果显示:绿球藻在高浓度氮和磷的污水中生长良好并维持较高的氮磷去除率,在6天处理期间,人工污水中总溶解性氮、硝酸盐氮、氨氮、总溶解性磷的去除率分别达到46.2%,37.8%,98.4%和79.3%;在对天然湖泊水的处理中,绿球藻对总溶解性磷的去除率在第5天为79.2%.

四种方法对鲢血清免疫球蛋白的纯化及分子量测定

采用mannan-binding protein(MBP)、TG及免疫亲和层析法和饱和硫酸铵沉淀法纯化鲢血清免疫球蛋白IgM,并比较了4种纯化方法的纯化效果.SDS-PAGE显示鲢血清免疫球蛋白的重链和轻链分子量分别为76.4 kD和27.2 kD,推算其总分子量约828.8kD.

Complex study of transport AC loss in various 2G HTS racetrack coils

HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance. © 2013 Elsevier B.V. All rights reserved.

乙炔基雌二醇对稀有鮈鲫肾脏的毒性效应

研究了环境相关水平的人工合成雌激素乙炔基雌二醇对稀有鲫肾脏的慢性毒性.结果表明,当暴露浓度达到20ng·L-1以上时,稀有鲫的肾脏指数显著增大,具有明显的剂量效应关系,肾脏组织表现出明显的病理学特征,肾小管内腔扩大,严重出血,有的被一种嗜曙红物质所填充,肾小管壁的管状上皮细胞严重肿大并出现退化和坏死,肾小管之间的间隙组织大量出现.肾脏的肿大导致了畸形个体出现.因此乙炔基雌二醇不仅可以导致鱼类的内分泌干扰效应,而且可以引发严重的肾脏组织损伤;鱼的肾脏指数和肾脏病理学变化可以作为评价环境雌激素类化合物毒性

离心力对制备沉积物间隙水中化合物浓度的影响

研究了离心力对间隙水化合物浓度的影响。将腐殖质掺入东湖沉积物样品 ,按泥∶水 =1∶4 (体积 )比室温下静置 30d ,随后掺入铜 ,泥∶水 =1∶4 (体积 )比静置 10d ,得到总有机碳含量在 1 4 7%— 5 72 %、铜含量在 12 0— 2 70 0mg/kg(干重 )的试验沉积物样品 ,用离心法制备沉积物中的间隙水。离心参数为 30 0 0r/min、5 2 0 0r/min、90 0 0r/min、10 5 0 0r/min和 12 0 0 0r/min ,4℃下离心 2 0min。间

梅子垭水库生态因子场的地统计学分析

应用地统计学方法，对梅子垭水库的典型理化因子的生态因子场的水平的2维空间格局进行了分析。通过空间相关性的分析，确定了生态因子场的整个空间和不同方位上的空间格局的变化情况。

一种海生黄藻的氨基酸和脂肪酸组成

对一种海生超微型藻类，品系ＰＰ９８３，的分类学地位、生长和生化组成进行了研究．形态学观察和色素分析表明，ＰＰ９８３ 是一种黄藻．在２５ ℃和１００ μｍｏｌ ｍ － ２ ｓ－１ 的条件下，ＰＰ９８３ 的生长速率为１．１５ ｄｉｖｄ，其对数生长期的蛋白质、脂肪和糖类质量分数分别为干重的４０ ．２％ 、２５ ．０ ％ 和１１ ．１％ ；共检出了１７ 种氨基酸，其总量为干重的２７．８ ％ ．ＰＰ９８３ 的多不饱和脂肪酸（ＰＵＦＡｓ）占总可提取脂肪酸的２６．４％ ，其中主要是ＥＰＡ，占干重的４．６％ ，而ＤＨＡ

Wave propagation in nonlinear one-dimensional soil model

The objective of the research conducted by the authors is to explore the feasibility of determining reliable in situ values of shear modulus as a function of strain. In this paper the meaning of the material stiffness obtained from impact and harmonic excitation tests on a surface slab is discussed. A one-dimensional discrete model with the nonlinear material stiffness is used for this purpose. When a static load is applied followed by an impact excitation, if the amplitude of the impact is very small, the measured wave velocity using the cross-correlation indicates the wave velocity calculated from the tangent modulus corresponding to the state of stress caused by the applied static load. The duration of the impact affects the magnitude of the displacement and the particle velocity but has very little effect on the estimation of the wave velocity for the magnitudes considered herein. When a harmonic excitation is applied, the cross-correlation of the time histories at different depths estimates a wave velocity close to the one calculated from the secant modulus in the stress-strain loop under steady-state condition. Copyright © 2008 John Wiley & Sons, Ltd.