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在静息时K＋外流及兴奋时Na＋内流是易化扩散中的通道蛋白介导扩散,顺着浓度梯度,需载体,不需要能量;在恢复静息电位时K＋重新移入和Na＋排出是主动运输,逆浓度梯度,需载体,需要能量。 相似文献
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目的：研究IL-4mRNA和IL-4蛋白在哮喘大鼠CD34^＋细胞中的转录表达及孟鲁司特（montelukast,MK）对其表达的影响。方法：将SD大鼠随机分为3组：哮喘组、MK组和正常对照组。用卵白蛋白制备大鼠哮喘模型。应用双抗体夹心酶联免疫吸附试验测定血浆中IL-4和γ-干扰素（IFN-γ）浓度;用MiniMACS磁珠分选系统分离骨髓CD34^＋细胞;采用SYBRGREEN I荧光实时定量PCR法测定CD34^＋细胞中IL-4mRNA的相对表达量。采用免疫组化技术测定CD34＋细胞中IL-4蛋白的表达量。结果：哮喘组骨髓CD34＋细胞中IL-4mR．NA和IL-4蛋白的表达量高于其它各组（p〈0．01）;哮喘组除了IFN-1水平低外,IL-4浓度和嗜酸性粒细胞（EOS）绝对值都是三组中最高的（P〈0．01）;除哮喘组外,其余组的各项指标相近（P〉0．05）。IL-4mRNA表达量与IL-4浓度、Eos绝对值呈正相关（P〈0．01）,与IFN-γ浓度呈负相关（P〈0．01）。结论：哮喘大鼠骨髓CD34^＋细胞中IL-4 mKNA的表达增强;孟鲁司特可以下调IL-4mRNA的表达。可能成为其抑制哮喘气道炎症形成的重要机制之一。 相似文献
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Er^3 -Yb^3 co-doped fiber of 2 m long is used as the laser gain medium. Two fiber lasers with different structures have been set up, one is the line cavity fiber laser with the dielectric mirror being replaced by an all-fiber reflecting mirror,the other is the ring cavity all-fiber laser. Both set-ups have achieved lasing operation at the wavelength of 1.53 μm. Pumped by the 1 064 nm light from all-solid-state Nd : YAG laser, the two fiber lasers at 1 530 nm are operational. Their output powers are 7.8 mW and 2 mW with 130 mW and 160 mW pump powers. 相似文献
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A process of biosorption of Cu2 , Zn2 and Cd2 on Bacillus subtilis was investigated. The experiments show that the process of biosorption is quite fast. The maximum adsorption was reached after 5 min and hardly changed with time. The experimental data was analyzed using four sorption kinetic models: the pseudo-first-order, the Ritchie second-order, the modified second-order and the Elovich equations, which helped to determine the best-fit equation for the sorption of metal ions onto biomass. The results show that both the Ritchie second-order and modified second-order equations can fit the experimental data. The Langmuir model is able to accurately describe adsorption of Cu2 and Zn2 on B. subtilis. The experimental data points of adsorption Cd2 and Zn2 on B. subtilis are described by Freundlich isotherms model. 相似文献
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目的:研究胃癌患者外周血中调节性T细胞(T regulatory cells,Tr)的CD4 和CD25 表达与胃癌临床病理的关系,并分析其意义。方法:采用流式细胞术检测44例胃癌患者和10例健康体检者外周血CD4 CD25 Tr水平,并进行分层分析。结果:健康成人对照组外周血Tr表达率为(6.05±1.88)%,胃癌患者外周血CD4 CD25 Tr细胞占总CD4 T细胞的(15.27±4.06)%,与健康对照组比较,外周血CD4 CD25 Tr细胞比率均明显升高,差异有显著统计学意义(P<0.01)。分层分析显示,胃癌外周血Tr表达与淋巴结转移率和TNM分期有着负相关性,淋巴结转移阳性和TNM分期越晚,Tr表达率越高(P<0.05)。结论:胃癌患者外周血CD4 CD25 Tr细胞比率明显升高,并与患者免疫力低下及临床病理存在显著相关性,提示祛除人的CD4 CD25 Tr细胞是一种有效的治疗肿瘤的新方法。 相似文献
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This paper examines the relationship between the February 2012 New York City teacher quality data release, the racial and ethnic composition of elementary and middle public schools and their neighborhoods, and housing prices. A unique dataset that links teacher quality to school characteristics, housing prices and characteristics, and Census data is used to estimate a difference-in-difference model to estimate the impact of the teacher quality release on housing prices. These results are then used to estimate the impact of the data release on residential and school demographics. The results in this study provide the first evidence of the effects of teacher quality measures on the housing market in New York City and the demographic shifts in residential and school mobility patterns as a result. The data suggests that the housing market responds significantly to the new information that was provided by the release of the teacher quality information, even when taking into consideration the school grades and other variables that may influence teacher quality measures. The magnitude of how much housing prices increase is greatly impacted by certain neighborhood demographics and the results show that Hispanic neighborhoods with a high proportion of free and reduced price lunch students are among the neighborhoods that had the highest increase in housing prices due to the teacher quality release. Not only that, but the areas that had the highest increase in housing prices due to the teacher quality release have experienced increases in the proportion of white students and the neighborhoods are becoming more racially diverse. 相似文献
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本文采用细胞微核技术，研究了不同浓度的Ｈｇ２＋对豌豆根尖细胞哟危害作用，结果表明：当Ｈｇ２＋的浓度为０．０５ｐｐｍ～１．５ｐｐｍ时，豌豆根尖细胞微核细胞率（Ｙ）与Ｈｇ２＋的浓度（Ｘ）星线性正相关，Ｙ＝１．２６７１＋１．４１８３Ｘ，ｒ＝０．９００６。部分报失发黑。 相似文献
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现代汉语中"PP 的 N V 得 RC"结构是一个多义的句法结构(其中"PP"代表人称代词,"N"代表名词,"V"代表动词,"RC"代表结果补语),本文通过变换分析和语义分析,指出其形成是组成此结构的各个部分相互整合的结果.其中结构助词"的"的不同功能是主要的原因。现代汉语的结构助词"的"有两种主要功能:领属性和区别性。 相似文献
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Liu Y Chen L Peng SY Chen ZX Hoang-Vu C 《Journal of Zhejiang University. Science. B》2005,6(9):913-918
Objectives: To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression and role of CD97 and its cellular ligand CD55 in gastric carcinomas. Methods: Tumor and corresponding normal mucosal tissue, collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97 and CD55. Results: CD97stalk was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The expression of CD97stalk was frequently observed in tumors of stage Ⅰ and T1 gastric carcinoma patients. The expression of CD97stalk between Stage Ⅰ and Stage Ⅱ, Ⅲ, Ⅳ specimens showed significant difference (P＜0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P＜0.05). Specimens with tumor invasion depth limited in mucosa of T 1 specimens showed higher positive CD55 expression than specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2, T3, T4 specimens was significantly different (P＜0.05).There was strong correlation between the distribution patterns of CD97stalk and CD55 on tumor tissues (r=0.73, P＜0.05). Signet ring cell carcinomas frequently contained strong CD97stalk and CD55-staining. Conclusions: Our results suggest that CD97stalk is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55. CD97stalk and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients. 相似文献
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Phenotypic and functional characteristics of dendritic cells derived from human peripheral blood monocytes 总被引：4，自引：0，他引：4
INTRODUCTION Dendritic cells(DCs)are professional anti-gen-presenting cells(APC)that are responsible for the activation of undifferentiated T cells and the generation of primary T-cell responses(Cella et al.,1997).The specific role of DCs is to capture,process and present antigens to T cells.Immunogenic and inflammatory signals are responsible for the migra-tion of DCs from tissues to lymphoid organs where they initiate an immune response.These processes induce the maturation of DCs… 相似文献
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Sun Jian 《上海大学学报(英文版)》1998,2(2):164-169
１ＩｎｔｒｏｄｕｃｔｉｏｎＨｙｐｅｒ－ＩｇＭｓｙｎｄｒｏｍｅ（ＨＩＭ）ｉｓａｒａｒｅｉｍｍｕｎｏｄｅｆｉｃｉｅｎｃｙｃｈａｒａｃｔｅｒｉｚｅｄｂｙａｎｉｎｃｒｅａｓｅｄｓｕｓｃｅｐｔｉｂｉｌｉｔｙｔｏｒｅｃｕｒｒｅｎｔｉｎｆｅｃｔｉｏｎｓａｎｄｍａｒ... 相似文献
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[目的]探讨粘附分子CD18、CD54粘附功能及其表达变化与急性脑梗塞(ACI)关系.[方法]用流式细胞术检测88例ACI患者白细胞粘附分子CD18、CD54含量与脑梗塞发生时程、部位、面积及治疗前后表达。并与30例正常人作对照.[结果]ACI患者CD18、CD54表达明显增高,与正常对照组比较差异显著(P<0.05),与梗塞面积、部位关系不大;ACI患者CD18、CD54表达在7d内均可有较高水平的表达,治疗10d后表达降低,治疗前后比较CD18、CD54差异有意义(P<0.05).[结论]CD18、CD54参与脑梗塞发生发展病理过程.可做为诊断脑梗塞、评估预后的一项辅助指标. 相似文献
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研究结果表明,在NH4+加入量较低时,随着NH4+加入量的增加,土壤对NH4+的吸附量呈线性增加,但NH4+的吸附率呈下降趋势;三种土壤对NH4+吸附量大小顺序为们土＞黄褐土＞水稻土． 相似文献
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Objectives: To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression
and role of CD97 and its cellular ligand CD55 in gastric carcinomas. Methods: Tumor and corresponding normal mucosal tissue,
collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97
and CD55. Results: CD97stalk was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The
expression of CD97stalk was frequently observed in tumors of stage I and T1 gastric carcinoma patients. The expression of CD97stalk between Stage I and Stage II, III, IV specimens showed significant difference (P<0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P<0.05). Specimens with tumor invasion depth limited in mucosa of T1 specimens showed higher positive CD55 expression than
specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2 T3, T4 specimens
was significantly different (P<0.05). There was strong correlation between the distribution patterns of CD97stalk and CD55 on tumor tissues (r=0.73,P<0.05). Signet ring cell carcinomas frequently contained strong CD97stalk and CD55-staining. Conclusions: Our results suggest that CD97stalk is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55.
CD97stalk and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients.
Project (No. 2004C34010) supported by the Science and Technology Bureau of Zhejiang Province, China 相似文献
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Recent increased interest in computational thinking poses an important question to researchers: What are the best ways to teach fundamental computing concepts to students? Visualization is suggested as one way of supporting student learning. This mixed-method study aimed to (i) examine the effect of instruction in which students constructed visualizations on students’ programming achievement and students’ attitudes toward computer programming, and (ii) explore how this kind of instruction supports students’ learning according to their self-reported experiences in the course. The study was conducted with 58 pre-service teachers who were enrolled in their second programming class. They expect to teach information technology and computing-related courses at the primary and secondary levels. An embedded experimental model was utilized as a research design. Students in the experimental group were given instruction that required students to construct visualizations related to sorting, whereas students in the control group viewed pre-made visualizations. After the instructional intervention, eight students from each group were selected for semi-structured interviews. The results showed that the intervention based on visualization construction resulted in significantly better acquisition of sorting concepts. However, there was no significant difference between the groups with respect to students’ attitudes toward computer programming. Qualitative data analysis indicated that students in the experimental group constructed necessary abstractions through their engagement in visualization construction activities. The authors of this study argue that the students’ active engagement in the visualization construction activities explains only one side of students’ success. The other side can be explained through the instructional approach, constructionism in this case, used to design instruction. The conclusions and implications of this study can be used by researchers and instructors dealing with computational thinking. 相似文献
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动脉粥样硬化性心血管疾病是危害人类健康的常见疾病之一.CD36是动脉粥样硬化发生和发展过程中的主要参与者之一,介导巨噬细胞内吞修饰的低密度脂蛋白,形成泡沫细胞,有明显的致动脉粥样硬化作用.本文介绍CD36的生物学特性及其在动脉粥样硬化中的作用. 相似文献