姚虻唾液腺抗血栓活性物质 tablysin2的原核表达及活性研究

吸血节肢动物在长期的环境胁迫下,进化出一套有利于其完成吸血活动的分子机制。吸血节肢动物的唾液腺可分泌多种有助于完成吸血过程的活性物质，其中包括血小板聚集抑制分子、抗凝血物质、溶栓物质、血管扩张分子、血管收缩抑制分子及其他一些相互作用分子。 虻虫作为传统的抗血栓中药具有具有悠久的应用历史。早在两千多年前《神农本草经》中就有“虻虫，性苦，微寒，主逐淤血，破血积、通利血脉及九窍”这样的记载。但是目前关于牛虻唾液腺抗血栓活性物质的研究很少，因此我们研究了一种牛虻——姚虻的唾液腺作为研究材料，希望从中寻找具有药用价值的抗血栓活性物质。我们还希望能利用微生物发酵工程对其进行小规模生产，以检测这些活性物质的体内活性，毒性等指标，为大规模的工厂化生产及临床应用奠定基础。 我们成功地从姚虻唾液腺cDNA文库中筛选到了抗血栓活性物质tablysin2，并利用大肠杆菌pET表达系统成功地对其进行了表达，获得了具有纤溶酶活性和血小板聚集抑制活性的tablysin2。这一工作进展解决了姚虻唾液腺资源紧缺对研究tablysin2的限制，为tablysin2的体内研究及临床应用创造了条件。此外，我们通过动物实验，初步断定tablysin2在18 ug/ml的剂量范围内不会引起组织出血。

Intense upconversion and infrared emissions in Er3+;Yb3+ codoped Lu2 Si O5 and (Lu0.5 Gd0.5)2 Si O5 crystals

High optical quality Lu2SiO5 (LSO) and (Lu0.5Gd0.5)(2)SiO5 (LGSO) laser crystals codoped with Er3+ and Yb3+ have been fabricated by the Czochralski method. Intense upconversion (UC) and infrared emission (1543 nm) are observed under excitation of 975 nm. The luminescence processes are explained and the emission efficiencies are quantitatively obtained by measuring the UC efficiency and calculating the emission cross section. The temperature-dependent optical properties of the crystals are also investigated. Our study indicates that Er3+-Yb3+ : LSO and Er3+-Yb3+: LGSO crystals are promising gain media for developing the solid-state 1.5 mu m optical amplifiers and tunable UC lasers. (c) 2008 American Institute of Physics.

Numerical study on NOx/CO emissions in the diffusion flames of high-temperature off-gas of steelmaking converter

The combustion of high-temperature off-gas of steelmaking converter with periodical change of temperature and CO concentration always leads to CO and NOx over-standard emissions. In the paper, high-temperature off-gas combustion is simulated by adopting counterflow diffusion flame model, and some influencing factors of CO and NOx emissions are investigated by adopting a detailed chemistry GRI 3.0 mechanism. The emission index of NOx (EINOx) decreases 1.7–4.6% when air stoichiometric ratio (SR) increase from 0.6 to 1.4, and it dramatically increases with off-gas temperature at a given SR when the off-gas temperature is above 1500 K. High-concentration CO in off-gas can result in high NOx emissions, and NOx levels increase dramatically with CO concentration when off-gas temperature is above 1700 K. Both SR and off-gas temperature are important for the increase of CO burnout index (BICO) when SR is less than 1.0, but BICO increase about 1% when off-gas temperature increases from 1100 K to 1900 K at SR > 1.0. BICO increases with CO concentration in off-gas, and the influence of off-gas temperature on BICO is marginal. BICO increases with the relative humidity (RH) in air supplied, but it increases about 0.5% when RH is larger than 30%.

用于HIRFL重离子治癌的PET成像实验研究与蒙特卡罗模拟

为了HIRFL重离子治癌的需要 ,使用两个位置灵敏闪烁体探测器组成了一个简单的PET成像系统 .对PET成像进行了实验研究 ,实验测量得到了物体成像以及γ射线能谱 ,对于 5 11keV全能峰处的能量分辨率为 18 6 % ,峰总比为 5 2 4 % .采用GEANT3程序对该系统进行了模拟计算 ,并与实验进行比较 ,最后对该系统进行了优化设计

Micro Insert: A Prototype Full-Ring PET Device for Improving the Image Resolution of a Small-Animal PET Scanner

A full-ring PET insert device should be able to enhance the image resolution of existing small-animal PET scanners. Methods: The device consists of 18 high-resolution PET detectors in a cylindric enclosure. Each detector contains a cerium-doped lutetium oxyorthosilicate array (12 x 12 crystals, 0.72 x 1.51 x 3.75 mm each) coupled to a position-sensitive photomultiplier tube via an optical fiber bundle made of 8 x 16 square multiclad fibers. Signals from the insert detectors are connected to the scanner through the electronics of the disabled first ring of detectors, which permits coincidence detection between the 2 systems. Energy resolution of a detector was measured using a Ge-68 point source, and a calibrated 68Ge point source stepped across the axial field of view (FOV) provided the sensitivity profile of the system. A Na-22 point source imaged at different offsets from the center characterized the in-plane resolution of the insert system. Imaging was then performed with a Derenzo phantom filled with 19.5 MBq of F-18-fluoride and imaged for 2 h; a 24.3-g mouse injected with 129.5 MBq of F-18-fluoride and imaged in 5 bed positions at 3.5 h after injection; and a 22.8-g mouse injected with 14.3 MBq of F-18-FDG and imaged for 2 h with electrocardiogram gating. Results: The energy resolution of a typical detector module at 511 keV is 19.0% +/- 3.1 %. The peak sensitivity of the system is approximately 2.67%. The image resolution of the system ranges from 1.0- to 1.8-mm full width at half maximum near the center of the FOV, depending on the type of coincidence events used for image reconstruction. Derenzo phantom and mouse bone images showed significant improvement in transaxial image resolution using the insert device. Mouse heart images demonstrated the gated imaging capability of the device. Conclusion: We have built a prototype full-ring insert device for a small-animal PET scanner to provide higher-resolution PET images within a reduced imaging FOV. Development of additional correction techniques are needed to achieve quantitative imaging with such an insert.

多组分单体接枝三元乙丙橡胶/PET共混体系的形态结构研究

以PS、DCP、GMA作为PET/EPDM共混体系的增容剂 ,以DSC和X射线衍射探讨了PET/EPDM共混物的结晶性能 ,以偏光显微镜和扫描电子显微镜探讨了共混物的形态。结果表明 ,PET/g EPDM共混体系的熔点可提高10℃ ,玻璃化温度降低 ,结晶起始温度提高约 2 0℃。共混体系中 ,当EPDM含量低时 ,PLM下观察到的是较为完整的球晶 ,随着EPDM含量逐渐提高 ,观察得到的是不完善的球晶、微晶、晶粒这样一个晶体变化过程 ,结晶完善程度降低。

成核剂1,3:2,4-二(亚苄基)-D山梨醇对PET/PEN共混体系结构和结晶形态影响

利用差示扫描量热仪、X射线衍射仪、正交偏光显微镜研究了成核剂 1,3 :2 ,4-二 (亚苄基 ) -D山梨醇(DBS)对聚对苯二甲酸乙二醇酯 (PET) /聚 2 ,6-萘二甲酸乙二醇酯 (PEN)共混体系的结构及结晶形态的影响。结果表明 :成核剂的加入 ,使PET/PEN共混体系熔融起始温度升高 10℃左右 ,结晶峰形变尖锐 ,说明加入成核剂后有效促进了PET/PEN共混体系的结晶。实验结果表明 :成核剂含量低于 1%时 ,PET/PEN共混体系晶体的球晶完整。成核剂含量大于 3 %时 ,PET/PEN /DBS共混体系晶体的球晶碎小。成核剂的加入 ,能够有效地减小球晶尺寸和降低球晶的完善性

第18届国际理论与应用力学大会(ICTAM-18)

<正> 由国际理论与应用力学联合会(IUTAM)召开的4年一次的第18届国际理论与应用力学大会(ICTAM-18),于1992年8月22—28日在以色列海法市的以色列工业学院举行。大会选定的3个主题是:固体与结构力学中的不稳定性;海面力学与海气相互作用;生物力学。设置主题分会的目的是对力学中的某些重要领域做综合介绍,以强调这领域的重要性,或对新领域起提倡作用。

激光毛化技术对18-8不锈钢疲劳性能影响的研究

通过模拟分析 ,对激光毛化 18 8不锈钢的疲劳寿命与毛化覆盖率的关系进行研究 ,预测结果与相关实验结果进行对比。结果显示 ,由于激光毛化处理的影响 ,18 8不锈钢的疲劳寿命得到改善 ,而且在毛化覆盖率为 2 0 %左右时 ,材料疲劳性能最好

脉冲激光辐照ZrO_2涂层的18-8不锈钢快凝组织与精细结构

利用脉冲辐照研究超高温度梯度下表层预轩ZrO_2纳米颗粒涂层的18-8奥氏体不锈钢的快凝组织形态、微结构特征及力学性质，结果表明，在表层约15μm范围内形成Zr的合金化微区，Zr最大含量(原子分数)为43.3%，但Zr成分分布存在不连续特征；预置纳米ZrO_2陶瓷涂层明显提高了激光作用深度。超高温梯度和高冷却速度显著细化了快凝亚组织并得到超细枝晶及胞晶，并观察到位错胞及栅栏孪晶两类亚晶，而激光熔区的外延生长机制未使晶粒细化。激光辐照后，合金化区硬度增加而弹性模量降低，其余部分硬度增加而弹性模量无变化。

Influence of HCl on CO and NO emissions in combustion

The influence of HCl on CO and NO emissions was experimentally investigated in an entrained flow reactor (EFR) and an internally circulating fluidized bed (ICFB). The results in EFR show the addition of HCl inhibits CO oxidation and NO formation at 1073 K and 1123 K. At the lower temperature (1073 K) the inhibition of HCl becomes more obvious. In ICFB, chlorine-containing plastic (PVC) was added to increase the concentration of HCl during the combustion of coal or coke. Results show that HCl is likely to enhance the reduction of NO and N2O. HCl greatly increases CO and CH4 emission in the flue gas. A detailed mechanism of CO/NO/HCl/SO2 system was used to model the effect of HCl in combustion. The results indicate that HCl not only promotes the recombination of radicals O, H, and OH, but also accelerates the chemical equilibration of radicals. The influence of HCl on the radicals mainly occurs at 800-1200 K. (C) 2009 Elsevier Ltd. All rights reserved.

Inter-stage line ratio of He- and Li-like Ti emissions for the electron temperature measurement

Under coronal conditions, the steady state rate-equations are used to calculate the inter-stage line ratios between Li-like Is(2)2p(P-2(3/2))-> 1s(2)2s -> ((2) S-1/2) and He-like 1s2p (P-1(1))-> 1s(2) (S-1(0)) transitions for Ti in the electronic temperature ranges from 0.1 keV to 20 keV. The results show that the. temperature sensitivities are higher at the electronic temperature less than 5000 eV and the temperature sensitivities will decrease with the increase of electronic temperature.