ISS： Efficient Search Scheme Based on Immune Method in Modern Unstructured Peer-to-Peer Networks

Flooding is the most famous technique for locating contents in unstructured P2P networks. Recently traditional flooding has been replaced by more efficient dynamic query （DQ） and different variants of such algorithms. Dynamic query is a new flooding technique which could estimate a proper time-to-live （TTL） value for a query flooding by estimating the popularity of the searched files, and retrieve sufficient results under controlled flooding range for reducing network traffic. However, all DQ-like search algorithms are ＂blind＂ so that a large amount of redundant messages are caused. In this paper, we proposed a new search scheme, called Immune Search Scheme （ISS）, to cope with this problem. In ISS, an immune systems inspired concept of similarity-governed clone proliferation and mutation for query message movement is applied. Some assistant strategies, that is, shortcuts creation and peer traveling are incorporated into ISS to develop ＂immune memory＂ for improving search performance, which can make ISS not be blind but heuristic.     

白藜芦醇抑制HeLa细胞肿瘤活性的自由基机理

白藜芦醇是一种植物抗毒素，属多元酚类。虽然迄今的研究表明，白藜芦醇能有效抑制许多癌细胞的肿瘤活性，但均未从自由基生物角度来阐明其抑制肿瘤活性的机理。该研究以离体HeLa细胞为材料，利用细胞培养法研究了白藜芦醇抗肿瘤活性的功效，以及产生这种功效的自由基途径，旨在从自由基生物学的角度进一步揭示白藜芦醇抗肿瘤活性的机量。噻唑蓝法及流式细胞仪分析结果表明，白藜芦醇能强烈抑制HeLa细胞增殖阻断HeLa细胞由S期向G2期转变。HeLa细胞内源性活性氧（ROS）及HeLa细胞内部氧化还原态的实验结果表明，白藜芦醇对细胞自分泌的总ROS有一定的抑制作用，它抑制HeLa细胞自分泌的O^-2浓度与抑制HeLa细胞增殖之间有明显的相关关系；同时，白藜芦醇可明显增高HeLa细胞内源SOD的活性以及GSH的含量，但可使CAT的活性显著下降，提示白藜芦醇能显著改变细胞内部的氧化还原态。以上结果为白藜芦醇抗癌机制提供了自由基生物学方面的实验依据。     

琼枝麒麟菜和异枝麒麟菜硫酸多糖及其水解产物的抑菌作用

目的：探讨琼枝麒麟菜（Eucheuma gelatinae）和异枝麒麟菜（Eucheuma striatum）硫酸多糖KCl分级产物，以及其经HCl水解的不同程度的水解产物对大肠埃希氏菌等8种细菌的抑菌作用，研究抗菌活性与样品化学组成的关系。方法：用肉汤释释法测定不同样品对不同菌株的最低抑菌浓度（MIC）；用明胶－BaCl2法测定硫酸基含量；用红外光谱初步分析琼枝和异枝麒麟友酸多糖及其水解产物化学组成的差异。结果：未水解的琼枝和异枝麒麟菜硫酸多糖均无抑菌活性；琼枝和划枝麒麟硫酸多糖的抑菌谱范围随着水解程度增加而增大；异枝麒麟菜硫酸多糖部分水解的水解产物的抑菌谱范围比琼枝麒麟菜硫酸多糖部分水解的水解产物广。结论：水解琼枝和异枝麒麟菜硫酸多糖抑菌活性的强弱和抑菌谱范围的大小可能与多糖中硫酸基含高低和所含κ－卡拉胶成分多少以及多糖水解程度有关。     

杜仲愈伤组织的诱导及增殖效应

以杜仲（Eucommia Umoidues Olive）的幼茎为外植体，接种于附加NAA、2，4-D、KT、6-BA及其组合的MS培养基上，均能产生愈伤组织，但MS 2，4-D的培养基上愈伤组织容易褐化，其他均可正常生长，MS NAA0.5mg/L 6-BA0.5mg/L KT1.0mg/L的培养基是适合愈伤组织的增殖培养的。     

Physiological responses of osteoblasts to cyclic stretching and the change of intracellular calcium concentration

The development of bone tissues is regulated by mechanical stimulation.Cyclic stretching was applied to the osteoblasts that were delivered from rat calvarie,The results showed that stretching at 500με increased the cell proliferation while loading at 1000με and 1500με inhabited cell growth ,Loading also increased the adhesive force between cells and substrate as well as spreading areas of osteobalsts.Furthermore,the fluorescence probe Fluo-3/AM was used to investigate the effect of stretching stimulation on the intracellular calcium concentration of osteoblasts.The intracellular calcium concentration of osteoblasts that were stretched at 500 με for 5 min was 92.9% higher than the control ,After being treated with the panax ontoginseng saponins,the streteched osteoblasts still expressed 28.6% higher intracellular calcium concentration than that of the control ,which proved that both the influx of extracellualr calcium and the release of intracellular calcium store were involved in the increase of intracellular calcium concentration when osteoblasts responded to the cyclic stretching And the influx of extracellular calcium through transmembrance channel played a main role.     

太白山地区常夏石竹愈伤组织增殖培养的研究

以太白山地区常夏石竹幼茎为外植体,采用正交设计实验,添加不同种类及不同浓度的植物生长调节物质,组成9种不同的增殖配方,对常夏石竹愈伤组织诱导、增殖试验。结果表明,6-BA是影响常夏石竹诱导率的最主要因素,最有利于常夏石竹愈伤组织增殖的植物生长调节剂组合为MS+6-BA 0.5 mg/L+2,4-D1.5 mg/L+NAA 0.1 mg/L,可促进常夏石竹愈伤组织的增殖,并能改善愈伤组织的生长状态,增加愈伤组织增殖生长量。     

LncRNA SIL沉默促进A549细胞增殖和迁移

研究了lncRNA SIL与肺纤维化中肺泡上皮细胞的增殖和迁移之间的关系.设计小干扰RNA沉默内源性lncRNA SIL的表达,通过RT-PCR、MTT、Western blot、细胞损伤修复实验及Transwell实验研究沉默后细胞的增殖和迁移变化.MTT结果显示:沉默lncRNA SIL后细胞的增殖能力与对照组相比...     

Recent insights into the role of integrins in cancer metastasis

Integrins have been repeatedly found involved in cancer metastasis. The past two years have seen considerable evolution in our knowledge on the role of these integrins in tumour cells. This includes the elucidation of different signalling pathways by which integrins dictate the anchorage-independent growth, survival and motility of tumour cells. Moreover, integrins may have a more complex role in cancer metastasis as they cooperate with serine proteases and metalloproteases to promote tumour cell invasion and angiogenesis. Finally, integrins favour tumor cell extravasation.     

肝再生细胞周期中增殖启动及其调控研究

肝再生细胞周期中增殖启动及其调控是一个研究热点,到底是何种因素及其涉及到的信号传导途径诱导了Go期肝细胞的启动仍然是一个谜.本文主要以JNK、TNF-α、IL-6、一氧化氮等因子及其可能参与的调控途径综述了肝再生启动的一些最新研究进展.     

Effect of olfactory ensheathing cells on reactive astrocytes <Emphasis Type="Italic">in vitro</Emphasis>

Olfactory ensheathing cells have been used in several studies to promote repair in the injured spinal cord. However, cellular interaction between olfactory ensheathing cells and glial cells induced to be reactive in the aftermath of injury site has not been investigated. Using an in vitro model of astrogliosis, we show that reactive astrocytes expressed significantly less glial fibrillary acidic protein (GFAP) when cultured both in direct contact with olfactory ensheathing cells and when the two cell types were separated by a porous membrane. Immunofluorescence staining also suggested that reactive astrocytes showed decreased chondroitin sulfate proteoglycans in the presence of olfactory ensheathing cells, although the reduction was not statistically significant. No down-regulation of GFAP was observed when reactive astrocytes were similarly cultured with Schwann cells. Cell viability assay and bromodeoxyuridine uptake showed that proliferation of reactive astrocytes was significantly increased in the presence of olfactory ensheathing cells and Schwann cells. Received 27 February 2007; received after revision 30 March 2007; accepted 3 April 2007