Voltage sensitivity of the osteoclast calcium receptor

We demonstrated previously that osteoclasts possess a divalent cation-sensitive "receptor", the Ca2+ receptor. Activation of the Ca2+ receptor by the surrogate cation Ni2+ was shown to elicit an increase in cytosolic [Ca2+] to a peak value followed by an exponential decline. In the present study we examined the influence of surface membrane voltage on the kinetics of Ca2+ receptor inactivation. The K+ ionophore, valinomycin was applied to intercept the declining phase of the cytosolic [Ca2+] transient elicited by application of between 50 microM- and 5 mM-[Ni2+]. This resulted in a sustained elevation of cytosolic [Ca2+] or even a 'hump' followed by a gradual decline. Such a kinetic alteration persisted in a Ca(2+)-free solution, but was abolished in high extracellular [K+] (105 mM). Thus, we demonstrate for the first time to our knowledge, a modulatory effect of membrane potential on the function of the osteoclast Ca2+ receptor.     

分布式多媒体系统中音频和视频实时传输

本文在分析了分布式多媒体实时传输系统的基础上 ,并说明了 RTP/ RTCP协议和 IP Multicast在单频和视频传输及控制中的应用。     

Design and performance evaluation of mixed manual and automatedcontrol traffic

We present a technology which allows manually controlled and automatically controlled vehicles to co-exist, thereby reducing much of the cost and infrastructure requirements in highway automation. An autonomous vehicle driving system (AVDS) is presented which only uses information from vehicle sensors, thereby eliminating the requirement that vehicles communicate with one another. This format allows gradual market penetration of AVDS, which makes the technology attractive from a systems implementation standpoint. To evaluate the performance of the mixed traffic, we simulate manual and automated vehicles together and show that our AVDS can lead to potentially large gains in capacity and smoother flow without the loss of safety     

AutoCAD应用系统的数据存取模式与SQL技术

讨论了CAD应用系统的两种数据存取方式及SQL技术 ,实现了多窗口消防CAD系统数据的高速存取。     

多窗口消防CAD系统用户界面及DCL技术

改造了AutoCAD多窗口显示技术 ,并获得所有窗口的控制权 ,实现了在不同窗口生成不同实体来表达某实体的不同形态。讨论了多窗口建筑消防CAD系统的用户菜单和对话框设计技术。     

企业网络安全系统的建设策略

本文从网络安全含义入手,对企业网络安全威胁、网络安全技术进行了分析和讨论,为企业网络建设提供理论参考。同时提出了企业网络安全系统的建设策略。     

The fracture characterization of highly irradiated Type 316 stainless steel

The fracture characteristics of 20% cold worked Type 316 stainless steel irradiated at 377–400°C to a fluence of 11 × 1022n/cm² (E > 0.1 MeV) were evaluated based on SEM fractography andJ-integral fracture toughness data. Compact tension specimens were tested at temperatures ranging from 232 to 649°C. A significant reduction in fracture toughness after irradiation was observed, which correlated well with the fracture morphology of the material. It was found that irradiation induces a shift in the transgranular-intergranular fracture transition temperature to a lower temperature. Irradiated specimens exhibited transgranular channel fracture from 232 to 538°C and intergranular fracture at 649°C, while unirradiated specimens failed in a transgranular ductile fracture mode up to 549°C. SEM fractographs revealed plate-like, faceted fracture surfaces of irradiated specimens. The faceted fracture appearance is associated with flow localization and dislocation channeling, phenomena that undoubtedly contribute to the decrease in fracture toughness. The possibility that ordered -phase particles are partially responsible for the reduced toughness as well as for irradiation hardening is discussed.

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Résumé En utilisant la fractographie SEM et des données de ténacité à la rupture basées sur l'intégrale J, on a évalue les caractéristiques à la rupture d'un acier inoxydable type 316 écroui de 20% et irradié à 377–400°C sous un flux intégré de 11.1022 n/cm² (c > 0.1 MeV).Des éprouvettes de traction compactes ont été soumises à essai à des températures comprises entre 232 et 649°C. On a observé une réduction significative de la ténacité à la rupture due à l'irradiation, ceci étant confirmé par la morphologie de la rupture. L'irradiation provoque un glissement de la température de transition de rupture intergranulaire-transgranulaire vers une température plus basse. Des échantillons irradiés ont fait état d'une rupture transgranulaire entre 232 et 530°C et d'une rupture intergranulaire à 649°C.Par contre, des échantillons non irradiés se sont rompus de manière transgranulaire jusqu'à 649°C. Les microfractographies révèlent, sur les éprouvettes irradiées, des surfaces de rupture à facettes, qui sont associées à une localisation de l'écoulement plastique et à une concentration des dislocations, phénomène qui, sans nul doute, contribue à réduire la ténacité à la rupture. On discute de la possibilité d'une responsabilité partielle de particules de phase y' dans la réduction de la ténacité et dans le durcissement dus à l'irradiation.