78 resultados para 801


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在本研究中,将福尔马林灭活的柱状黄杆菌菌苗(FKG4)经腹腔注射免疫草鱼,以注射灭菌PBS作对照,分别在免疫后1、7、15和28d,提取受免鱼和对照鱼肝脏、脾脏和头肾3种组织中的总RNA并反转录成cDNA,利用Real-time PCR方法对不同组织中C-反应蛋白(CRP)、主要组织相容性复合体I(MHCⅠ)、肿瘤坏死因子(TNFα)、白介素1(IL-1β)、白介素8(IL-8)、Ⅰ型干扰素(IFNⅠ)等6种免疫相关基因的表达进行定量分析。结果发现CRP在受免鱼肝脏中的表达于免疫后1、7d显著高于对照鱼,

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Detecting objects in their paths is a fundamental perceptional function of moving organisms. Potential risks and rewards, such as prey, predators, conspecifics or non-biological obstacles, must be detected so that an animal can modify its behaviour accordingly. However, to date few studies have considered how animals in the wild focus their attention. Dolphins and porpoises are known to actively use sonar or echolocation. A newly developed miniature data logger attached to a porpoise allows for individual recording of acoustical search efforts and inspection distance based on echolocation. In this study, we analysed the biosonar behaviour of eight free-ranging finless porpoises (Neophocaena phocaenoides) and demonstrated that these animals inspect the area ahead of them before swimming silently into it. The porpoises inspected distances up to 77 in, whereas their swimming distance without using sonar was less than 20 in. The inspection distance was long enough to ensure a wide safety margin before facing real risks or rewards. Once a potential prey item was detected, porpoises adjusted their inspection distance from the remote target throughout their approach.

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Random amplified polymorphic DNA (RAPD) molecular markers specific for one, two or three clones have been identified from five gynogenetic clones of silver crucian carp (Carassius auratus gibelio Bloch) using RAPD markers developed earlier. In this study, three RAPD markers (RA1-PA, RA2-EF and RA4-D) produced by Opj-1, and two RAPD DNA fragments (RA3-PAD and RA5-D) produced by Opj-7, were selected for molecular cloning and sequencing. Sequence data indicated that there were identical 801-bp nucleotide sequences in the shared marker RA1-PA cloned respectively from clones P and A, and the shared marker RA2-EF (which was cloned from clones E and F), were also of identical 958-by nucleotide sequences. The nucleotide sequences of the shared marker RA3-PAD fragments were also similar for 1181 by among clones P, A and D. The specific fragment RA4-D was composed of 628 bp, and the fragment RA5-D from clone D contained 385 nucleotides. According to the nucleotide sequences, we designed and synthesized five pairs of sequence characterized amplified regions (SCAR) primers to identify the specific fragments in these gynogenetic clones of silver crucian carp. Only individuals from clones P and A amplified a specific band using a pair of SCI-PA primers synthesized according to the marker RA1-PA sequences, whereas no products were detected in individuals from clones D, E and F. The PCR products amplified using SC2-EF and SC3-PAD primers were as expected. Furthermore, the pair of SC4-D primers amplified specific bands only in individuals from clone D, although weak bands could be produced in all individuals of the five clones when lower annealing temperatures were used. However, an additional pair of SC5-D primers designed from the RA5-D marker sequences could amplify a DNA band in individuals from clones P, A and D, and the same weak band was produced in clone E, whereas no products were detected in individuals from clone F. Searches in GenBank revealed that the 385-bp DNA fragment from RA5-D was homologous to the 5' end of gonadotropin I beta subunit 2 gene and growth hormone gene. No homologous sequences were found for other markers in GenBank. The SCAR markers identified in this study will offer a powerful, easy, and rapid method for discrimination of different clones and for genetic analyses that examine their origins and unique reproductive modes in crucian carp. Furthermore, they will likely benefit future selective breeding programs as reliable and reproducible molecular markers. (C) 2001 Elsevier Science B.V. All rights reserved.

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Resting metabolism was measured in immature mandarin fish Siniperca chuatsi weighing 42.1-510.2 g and Chinese snakehead Channa argus weighing 41.5-510.3 g at 10, 15, 20, 25, 30 and 35 degreesC. Heat increment of feeding was measured in mandarin fish weighing 202.0 (+/-14.0) g and snakehead weighing 200.8 (+/-19.3) g fed swamp leach Misgurnus anguillicaudatus at 1% body weight per day at 28 degreesC. In both species, weight exponent in the power relationship between resting metabolism and body weight was not affected by temperature. The relationship between resting metabolism and temperature could be described by a power function. The temperature exponent was 1.39 in mandarin fish and 2.10 in snakehead (P < 0.05), indicating that resting metabolism in snakehead increased with temperature at a faster rate than in mandarin fish. Multiple regression models were used to describe the effects of body weight (W, g) and temperature (T, C) on the resting metabolism (R-s, mg O-2/h): In R-s = - 5.343 + 0.772 In W + 1.387 In T for the mandarin fish and In R-s = -7.863 + 0.801 ln W + 2.104 In T for the Chinese snakehead. The proportion of food energy channelled to heat increment was 8.7% in mandarin fish and 6.8% in snakehead. (C) 2000 Elsevier Science Inc. All rights reserved.

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A spin-injection/-detection device has been fabricated based on the multiple quantum well light emitting diode (LED) structure. It is found that only a broad electroluminescence (EL) peak of a full width at half maximum of 8.6 nm appears at the wavelength of 801 nm in EL spectra with a circular luminescence polarization degree of 18%, despite PL spectra always show three well resolved peaks. The kinetic energy gained by injected electrons and holes in their drift along opposite directions broadens the EL peak, and makes three EL peaks converge together. The same process also destroys the injected spin polarization of electrons mainly dominated by the Bir-Aronov-Pikus spin relaxing mechanism.

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在一个安全的代理签名方案中,只有指定的代理签名人能够代表原始签名人生成代理签名.基于椭圆曲线离散对数问题,纪家慧和李大兴提出了一个代理签名方案和一个代理多签名方案,陈泽雄等人给出了另外两个代理多签名方案.但是,在他们的方案中,原始签名人能够伪造代理签名私钥.为了抵抗原始签名人的伪造攻击,改进了代理签名密钥的生成过程,并对改进的方案进行了安全性分析.

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基于模型的故障诊断方法是重要的故障诊断方法之一,该方法主要的问题就是如何求得所有的诊断.该文利用系统的结构信息,给出了求极小冲突集的一个算法,证明了算法的正确性,分析了算法的复杂性;然后介绍了如何由极小冲突求得诊断.其次,还给出了利用结构信息直接求诊断的一个算法,证明了其正确性.最后与相关工作进行了比较.该文给出的算法,对于一些特殊结构的系统可在多项式时间内结束.

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根据WebOffice系统中浏览器-服务器端通信需求,提出了一种调用Web服务的浏览器端代理方法.比较了此方法和传统的服务器端方法的优点和缺点,分析了此方法的适用场合.最后给出了实现的要点:WSDL的加载和解析、对象类型的序列化和反序列化、SOAP协议的封包和绑定.

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一、大鼠海马-前额叶回路在学习记忆中的作用 解剖学研究证实大鼠和猴的海马结构(hippocampal formation, HF;本文‘海马 (hippocampus, Hip)’一词即指海马结构)和前额叶 (prefrontal cortex, PFC) 之间存在一条单向、同侧和单突触的神经回路,即海马-前额叶回路(Hip-PFC回路)。Hip和PFC均参与学习记忆等多种认知功能,PFC是工作记忆的关键脑区,而Hip是空间参考记忆的关键脑区。虽然人们已经对PFC和Hip进行了广泛深入的研究,但对Hip-PFC回路参与哪些认知功能还知之甚少。本研究的目的就是通过暂时阻断Hip-PFC回路,探讨其在学习和记忆中的作用。 在大鼠,Hip-PFC回路中的纤维主要从Hip腹部 (ventral hippocampus, VH)发出,投射到PFC的前边缘皮质(prelimbic cortex, PLC)、下边缘皮质 (infralimbic cortex, ILC) 和外侧前额叶 (lateral prefrontal cortex) 等亚区,其中PLC是Hip-PFC主要投射的区域。我们通过给动物安装慢性导管向脑内注射GABAA受体激动剂muscimol (MU) 阻断Hip-PFC回路。注射位点包括 ①双侧PLC,②双侧VH,③一侧VH和对侧PLC (VH-PLC)。我们首先观察了在PLC或VH局部注射MU对自由活动大鼠PLC和VH脑电功率的影响,并以此确定在行为实验中所用蝇蕈醇的剂量。然后采用T-迷宫空间交互延缓作业 (spatial delayed alternation task) 测试Hip-PFC回路被阻断的动物的空间工作记忆功能;采用被动回避作业 (passive avoidance task) 测试其情绪相关记忆的能力(训练前给药;24 h后重测试);采用Morris水迷宫作业 (Morris water maze task) 测试其空间参考记忆的能力(每天训练前给药;训练期(3 d)结束24 h后重测试)。结果表明:在大鼠PLC或VH局部注射0.5 μg/0.25μl MU后30 min显著抑制VH 和PLC的脑电功率 (VH, p < 0.01; PLC, p < 0.05 vs. PBS/baseline)。注射MU (0.5 μg/0.25μl) 到 ①双侧PLC、②双侧VH、③VH-PLC均显著降低动物在空间交互延缓作业 (All p < 0.001, vs. PBS) 和空间Morris水迷宫作业中的成绩 (All p < 0.05, vs. PBS),表明Hip-PFC回路在空间工作记忆(空间短时记忆)和在空间参考记忆(空间长时记忆)中均起重要作用。在空间交互延缓作业中,双侧PLC被抑制的大鼠的成绩显著低于双侧VH或VH-PLC被抑制的动物,说明PFC在空间工作记忆功能中占有主导地位。在被动回避作业中,双侧VH被抑制动物的回避反应的潜伏期显著短于对照动物 (p < 0.05 vs. PBS),说明双侧VH被抑制动物的情绪记忆受损;而双侧PLC或VH-PLC被抑制的动物其回避反应的潜伏期与对照动物无显著差异 (PLC, p > 0.9; VH-PLC, p > 0.3 vs. PBS),表明双侧PLC或VH-PLC被抑制的动物情绪记忆正常。被动回避作业的结果说明VH参与情绪记忆的形成,但Hip-PFC回路在情绪记忆形成中不起重要作用。 以上结果表明,大鼠Hip-PFC回路参与空间工作记忆和空间参考记忆而不是情绪记忆功能。情绪记忆的关键脑结构是杏仁复合体 (amygdala complex, AMC),VH与AMC有密切的纤维联系。VH被抑制的大鼠情绪记忆受损,说明情绪记忆可能与AMC-Hip回路有关。情绪记忆与空间记忆(参考记忆和工作记忆)在解剖上的分离说明,对于不同类型的记忆来说,其在脑内的信息加工过程是并行的。神经回路内部的信息加工过程则是串行的,回路上任何一个结构的破坏均可导致回路功能的损伤。本研究的结果为学习记忆的“多重记忆系统”理论和记忆信息加工的串行并行机制提供了新的实验证据。 二、芬克罗酮改善成年恒河猴空间工作记忆的谷氨酸机制 芬克罗酮是中科院昆明植物所郝小江等合成的取代吡咯烷酮类化合物。中科院昆明动物所蔡景霞等发现芬克罗酮能改善东莨菪碱、育亨宾等导致的多种动物的不同类型的学习记忆障碍,提高老年动物的学习记忆能力,尤其是老年猴的空间工作记忆。已证实芬克罗酮为部分钙激动剂,可使脑缺血沙土鼠脑内升高的谷氨酸降低,而使正常的沙土鼠海马胞外谷氨酸释放增加。那么芬克罗酮能否提高正常动物的学习记忆,其对正常动物学习记忆的提高是否与其增加谷氨酸的释放有关?本研究采用空间延缓反应作业和谷氨酸NMDA受体拮抗剂MK-801在正常成年猴恒河猴上探讨了以上问题。 结果表明,口服芬克罗酮可显著提高成年猴的空间工作记忆,其量效曲线呈倒‘U’形,符合许多促智药的量效特点。0.25 mg/kg和0.5 mg/kg为芬克罗酮的最佳有效剂量 (p < 0.05 vs. 安慰剂)。肌注MK-801 (0.1 mg/kg) 显著降低成年猴的空间工作记忆 (p < 0.01 vs. 安慰剂),而口服2.0 mg/kg和4.0 mg/kg的芬克罗酮则显著改善MK-801导致的工作记忆障碍 (p < 0.05 vs. MK-801)。芬克罗酮的所有测试剂量不影响猴在作业中的反应时 (p > 0.05 vs. 安慰剂),表明芬克罗酮在该剂量范围不影响动物的运动能力。 本研究结果提示,芬克罗酮可能通钙激动作用促进谷氨酸的释放,在一定剂量范围内提高胞外谷氨酸水平,提高正常动物的空间工作记忆等认知功能。 关键词:芬克罗酮,恒河猴,空间工作记忆,空间延缓反应作业,谷氨酸,MK-801

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分析了采用双面键合长波长面发射激光器时,键合界面光吸收系数和电、热导率的变化对器件的光、热性质的影响。对于1入光学腔的面发射激光器,键合界面吸收系数对器件光学性能影响较大,而对于1.5入光学腔的面发射激光器,其光学性能基本不受键合界面吸收系数的影响。由有限元方法对面发射激光器的温度分布计算结果可知,当键合界面电、热导率小于GaAs电、热导率的1%时,激光器有源层的温度会有较大的上升。

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半导体纳米结构是纳米材料的一个重要组成部分,纳米结构的电子和光子器件将成为下一代微电子和光电子器件的核心.半导体纳米结构有多种多样,如自组织量子点、纳米晶体、硅团簇、量子结构等,它们可以制成各种纳米电子学器件.根据以上几类半导体纳米结构,文章介绍的获奖项目提出了研究半导体纳米结构电子结构的四个理论,并利用这些理论研究了它们的电子态和物理性质,发现了许多新的效应.这些理论包括

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土壤有机碳、全氮的空间分布及特性研究一直是土壤学研究的热点,研究东北黑土有机碳、全氮的空间分布和特性可以为东北黑土退化机理及可持续利用提供理论依据。本文以东北黑土区1200个样点为基础,依据尺度分布理论,采用宏观统计分析和微观化学分析相结合,研究了黑土有机碳、全氮空间分布规律;黑土有机碳与其它养分之间的关系;黑土有机碳、全氮在团聚体中的富集以及黑土活性有机碳、氮的区域分布特性。本次研究是继第二次土壤普查以来对黑土有机碳系统研究,首次摸清了东北黑土有机碳库的现状和分布规律,及其与其它养分库的关系,采用经典统计学方法绘制了黑土有机碳空间分布图;对影响有机碳库和养分的驱动因素进行了分析,发现了黑土有机碳库的“经向”和“纬向”分布规律;总结了黑土有机碳库频数分布特征,以及自第二次土壤普查以来几十年间的变化。探讨了土壤有机碳空间分布的驱动因子,绘制了土壤有机碳、全氮的空间分布等值线图,阐明了土壤活性有机碳、氮库的空间分布对土壤有机碳库的贡献: 1、土壤有机碳、全氮水平空间分布在纬向上主要受温度控制,在经向上主要受水分控制,黑土有机碳与纬度的显著相关(r=0.70188, P<0.01),与黏粒显著正相关(r=0.43, P<0.01),与砂粒显著负相关(r=-0.44, P<0.01)。 2、土壤有机碳、全氮垂直空间分布在一定深度内受温度控制,水分状况作用较小,黏粒在深度剖面作用不显著,随着土壤深度的增加,土壤有机C和全N含量降低。 3、土壤团聚体组分中有机碳、全氮含量与纬度呈正相关关系,大团聚体和微团聚体更易受水热条件影响,大团聚体的有机碳富集因子E≥1的趋势明显而微团聚体及粉+黏组分有机碳的富集因子E≤1的趋势明显,说明大团聚体中有机碳具有累积趋势而微团聚体和粉+黏组分中有机碳处于消耗状态。 4、黑土其它养分的分布均非正态分布,有机碳与全磷、全钾、碱解氮、速效钾和速效磷之间的相关关系分别为0.795、-0.295、0.801、0.244和0.036,只有有机碳和速效磷之间没有相关性,而与其它养分在P<0.01水平呈显著相关。 5、土壤活性有机碳和活性有机氮随纬度增加活性组分增大,土壤活性有机碳的比例较小,说明黑土有机物料输入较低;黑土活性有机氮含量差别不大,说明微生物活动相似。