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排序方式: 共有840条查询结果,搜索用时 15 毫秒
61.
Macpherson AJ Martinic MM Harris N 《Cellular and molecular life sciences : CMLS》2002,59(12):2088-2096
There is an immense load of non-pathogenic commensal bacteria in the distal small intestine and the colon of mammals. The
physical barrier that prevents penetration (translocation) of these organisms into the body is a simple epithelium comprised
of the single enterocyte/colonocyte cell layer with its overlying mucus. In this review, we discuss the roles of intestinal
T cells in initiating and regulating innate and adaptive mucosal immune responses of the mucosal immune system that avoid
or limit penetration of the commensal intestinal bacteria.
Received 9 August 2002; accepted 9 September 2002
RID="*"
ID="*"Corresponding author. 相似文献
62.
Programmed cell clearance 总被引:10,自引:0,他引:10
Fadeel B 《Cellular and molecular life sciences : CMLS》2003,60(12):2575-2585
Apoptosis, a physiological process of self-annihilation, is essential during development and for the maintenance of tissue homeostasis. Considerable efforts have been made in recent years to elucidate the molecular mechanisms that govern this mode of cellular demise; however, the subsequent recognition and removal of apoptotic corpses by neighboring phagocytes has received less attention. Nevertheless, macrophage engulfment of apoptotic cells is known to be important in the remodeling of tissues, and contributes to the resolution of inflammation through the removal of effete cells prior to the release of noxious cellular constituents. Moreover, apoptotic cells are a potential source of self-antigens, and clearance of cell corpses is thought to preclude the induction of autoimmune responses. The view is thus emerging that tissue homeostasis is dependent not only on the balance between mitosis and apoptosis, but also on the rate of apoptosis versus that of cell clearance. This review aims to discuss the mechanisms and consequences of macrophage recognition and disposal of apoptotic cells, a process which will be referred to as programmed cell clearance.Received 16 April 2003; received after revision 22 May 2003; accepted 26 May 2003 相似文献
63.
帧内预测是H.264视频编解码标准中一项重要的技术,极大地提高了H.264的编码效率。然而,帧内预测的亮度块有13种预测模式。为选出最佳模式,全搜索算法需要花费极大的计算量。为了降低帧内预测的复杂度,提出了一种基于变换域的快速帧内预测算法。实验结果表明:与全搜索相比,改进的算法在保持PSNR基本不变和码率增加很小的情况下,使帧内预测编码的速度提高70%左右。 相似文献
64.
王雪芹 《南京体育学院学报(自然科学版)》2007,6(1):24-26,46
巨噬细胞(Mφ)是参与免疫应答的重要细胞。中、小强度的运动使巨噬细胞的吞噬能力增强,而大强度运动使巨噬细胞的吞噬能力下降;同时运动也使机体内一些神经递质、激素的分泌水平发生变化,而激素、神经递质的改变又影响神经内分泌系统对巨噬细胞的免疫调节作用。 相似文献
65.
The effect of carboxymethytl pachymaram (CMP) on the function of dendritic cells(DCs) derived from spleens of hepatitis B
virus transgenic mice are studied in vitro. The phenotypes of DCs are tested by flow cytometry (FCM), cytokines measured by ELISA. The expression of DCs’ phenotypes
in HBV transgenic mice are low (CD80+CD11c+:59.12±11.53 vs 9.60±4.53, p<0.01; CD80+ MHC-II+: 44.86±12.31 vs 9.80±5.72, p<0.01, normal mice vs HBV transgenic mice), the ability of DCs stimulating T lymphocytes proliferation decreases (0.37±0.11 vs 0.20±0.11, p<0.05, normal mice vs HBV transgenic mice), levels of IL-12 and IFN-γ decrease whereas the level of IL-10 increases; CMP can enhance DCs’ ability of stimulating T lymphocytes proliferation, facilitate
the secretion of IL-12 and IFN-γ, inhibit the secretion of IL-10, thus up regulates DCs function. The results show a good prospective use of CMP on the treatment
of chronic hepatitis B.
Biography: HOU Anji (1963–), male, Ph.D. candidate, Associate professor, research direction: clinical virology. 相似文献
66.
ZHANG Jian HUANG Min HAN Guoqiang 《武汉大学学报:自然科学英文版》2007,12(3):442-446
For the encoding bit-rate problem in H.264 wireless video communication,this paper analyzes the bit-rate computation model and the Mean Square Error distortion model,establishes the relation between the quantization parameter of the encoding bit-rate and the intra frame refresh rate of the macro block,and put forward a new ideal about the coding rate on the basis of general binomial computation model theory. Furthermore,this method not only can adaptively adjust the bit allocation and quantization parameter and prevents buffer from overflowing downward or upward under given network bandwidth,but also can apply the rate-distortion to optimize the solution method,control the encoding bits accurately and optimizes the allocation between the intra and inter frame encoding macro block. 相似文献
67.
随着生命科学研究的发展,动物实验中小鼠的使用频率越来越高。实验人员对实验小鼠不明原因的脱毛现象十分困扰,影响实验结果的判断,本文针对小鼠的非病理性脱毛,简述包括自然发生和偶然诱导脱毛的原因,实验人员可根据具体情况作出科学的判断。 相似文献
68.
Summary Neutral free D-amino acid contents in the serum, kidney, liver, brain, small intestine and urine in germ-free mice and those in specific pathogen-free mice were compared. No significant difference was found. This strongly suggests that the free D-amino acids which were shown to be present in mice in our previous work1, 2 did not originate from the enteric microbial flora. 相似文献
69.
70.
观察新氨基酸螯合钙制剂--L-亮氨酸钙对小鼠股骨生长的影响.将昆明(KM)系小鼠随机分成5组,分别喂养高、中、低剂量的L-亮氨酸钙和葡萄糖酸钙,通过测量相应饲料喂养小鼠的体质量、血清钙质量浓度、股骨长度、股骨质量和股骨中钙的质量分数等指标,观察亮氨酸钙对KM系小鼠股骨生长的影响.结果表明:L-亮氨酸钙对小鼠体质量差异无... 相似文献