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271.
Image-guided computer aided surgery system (ICAS) contributes to safeness and success of surgery operations by means of displaying anatomical structures and showing correlative information to surgeons in the process of operation. Based on analysis of requirements for ICAS, a new concept of clinical knowledge-based ICAS was proposed. Designing a reasonable data structure model is essential for realizing this new concept. The traditional data structure is limited in expressing and reusing the clinical knowledge such as locating an anatomical object, topological relations of anatomical objects and correlative clinical attributes. A data structure model called mixed adjacency lists by octree-path-chain (MALOC) was outlined, which can combine patient's images with clinical knowledge, as well as efficiently locate the instrument and search the objects' information. The efficiency of data structures was analyzed and experimental results were given in comparison to other traditional data structures. The result of the nasal surgery experiment proves that MALOC is a proper model for clinical knowledge-based ICAS that has advantages in not only locating the operative instrument precisely but also proving surgeons with real-time operation-correlative information. It is shown that the clinical knowledge-based ICAS with MALOC model has advantages in terms of safety and success of surgical operations, and help in accurately locating the operative instrument and providing operation-correlative knowledge and information to surgeons in the process of operations. 相似文献
272.
273.
李发根 《上海交通大学学报(英文版)》2008,13(6):679-683
We show that the Zhang-Yang-Zhu-Zhang identity-based authenticatable ring signcryption scheme is not secure against chosen plaintext attacks.Furthermore, we propose an improved scheme that remedies the weakness of the Zhang-Yang-Zhu-Zhang scheme.The improved scheme has shorter ciphertext size than the Zhang-Yang-Zhu-Zhang scheme.We then prove that the improved scheme satisfies confidentiality, unforgeability, anonymity and authenticatability. 相似文献
274.
The parameter values which actually change with the circumstances, weather and load level etc.produce great effect to the result of state estimation. A new parameter estimation method based on data mining technology was proposed. The clustering method was used to classify the historical data in supervisory control and data acquisition (SCADA) database as several types. The data processing technology was impliedto treat the isolated point, missing data and yawp data in samples for classified groups. The measurement data which belong to each classification were introduced to the linear regression equation in order to gain the regression coefficient and actual parameters by the least square method. A practical system demonstrates the high correctness, reliability and strong practicability of the proposed method. 相似文献
275.
To improve the braking safety of automobiles, the author studied the effect of differential brake on the stabilities. To analyze the mechanical characteristics of differential brake, automotive subsystem models were built by applying ADAMS/CAR, and automotive mechanics simulation model was built by setting the main subsystems such as body, engine and brake. The simulation model studied the distribution mode of three kinds of differential brake, and beeline braking stability and turning braking stability were simulated. It shows that differential brake can amend turning shortage of automobile brake and improve its braking stability, but the effect of automobile mass on its braking stability is great. So the distribution mode of braking force and the effect of mass change should be considered while differential brake is applied. 相似文献
276.
Objective To study the changes in neuronal activity of the zone incerta (ZI) following the unilateral lesion of the nigrostriatal pathway. Methods Eiectrophysiological recordings of ZI neurons were made in normal rats and in two groups of rats at different time intervals after injection of 6-hydrodopamine (6-OHDA) into the pars compacta of snbstantia nigra by extracellular recording in vivo. Results The results showed a significant increase in the mean firing rate of ZI during the second and fourth weeks after 6-OHDA lesion [-n=32, (3.6±2. 2)Hz, P<0.001; n=35, (9.3±6.6)Hz, P<0. 001, respectively] compared to that of normal rats [n=39, (9.2±5.2)Hz]. However, no significant change was observed between two groups of 6-OHDA-lesioned rats. With regard to firing pattern, 7.7%(3/39) of ZI neurons discharged regularly, 82.1% (32/39) irregularly and 10. 3% (4/39) in bursts in normal rats. During the second week after 6-OHDA lesion, the regular, irregular and bursting firing neurons recorded in the ZI were 9.4% (3/32), 59. 4% (19/32) and 31.3% (10/32), and during fourth week, the regular, irregular and bursting firing neurons were 14.3% (5/35), 57.1% (20/35) and 28. 6% (10/35), respectively. The firing pattern of the neurons in the three different groups did not change significantly. Conclusion These results suggest that the firing rate of ZI neurons in 6-OHDA-lesioned rats is increased significantly, which may contribute to the pathophysiology of Parkinson's disease. 相似文献
277.
Objective To investigate changes in T lymphocyte subsets and NK cells in patients with simple Graves' disease (GD)and Graves' disease combined with type 2 diabetes mellitus (GD/T2DM). Methods Fifteen cases of GD/ T2DM were selected from our hospital from November 2001 to November 2004. Before and after therapy thyroid function, thyroglobulin antibody (TGA), thyroid microsomal antibody (TMA) and blood glucose level were measured, and T lymphocyte subsets (CD3, CD4, CD8, CD4/CD8) and NK cells (CD56) were measured by immunofluorescence double labeling monoclonal antibody and flow cytometry, respectively. At the same time, comparison was made with simple GD (15 cases), T2DM (15 cases) and healthy control (20 cases). Results Before therapy, CD4/CD8, CD4 and NK cells in GD/T2DM were less than normal, and there was no significant difference in comparison with simple GD (P<0.05). In T2DM group, only CD4/CD8 and CD4 were less than those of healthy controls (P<0.05). When thyroid function recovered after 1 to 3 months of methimazole treatment in both GD/T2DM and simple GD groups, various indexes recovered, which were more obvious in simple GD. Conclusion Immune hypofunction of GD may be the key to the immune abnormality of GD/T2DM, which is more significant than that of simple GD or T2DM. The recovery of thyroid function and immune abnormality is not consistent, and the recovery of GD is more significant than that of GD/T2DM. 相似文献
278.
沙棘果油及沙棘籽油对大鼠放射性皮肤损伤的影响 总被引:2,自引:0,他引:2
目的观察沙棘果油及沙棘籽油对大鼠放射性皮肤损伤的影响。方法实验用深部X线治疗机,每次以3000 cGy的剂量,照射两次,造成大白鼠臀部放射性皮肤损伤。待动物症状明显后,将Ⅱ度皮肤损伤的动物随机分为6组,即阴性对照组、沙棘果油高剂量组、沙棘果油低剂量组、沙棘籽油高剂量组、沙棘籽油低剂量组以及阳性对照组。沙棘果油及籽油高剂量组,每天在损伤部位涂药两次,而其低剂量组每天涂药一次,阴性对照组每天涂灭菌的注射用水一次,阳性对照组每天涂Solcoseryl-Jelly软膏一次。结果肉眼观察结果显示,连续用药10d后,沙棘果油、籽油及Sol-coseryl-Jelly组动物的局部红斑、水肿明显减轻,创面分泌物明显减少,用药2周后,上述症状明显消退,与阴性对照组比较,明显好转;另外,沙棘果油、籽油及Solcoseryl-Jelly组的创面愈合时间明显缩短。光学显微镜观察结果显示,沙棘果油、籽油及Solcoseryl-Jelly组的皮肤损伤明显减轻,炎症反应亦明显减轻,创面修复明显。电子显微镜观察结果显示,阴性对照组的超微结构明显受损,而沙棘果油、籽油及Solcoseryl-Jelly组的损伤明显减轻。结论沙棘果油及沙棘籽油对大鼠放射性皮肤损伤有明显的治疗作用。 相似文献
279.
目的 探讨WWOX(WW domain-containing oxidoreductase)基因在非小细胞肺癌组织中的表达及其临床意义.方法 用免疫组化方法检测50例鳞癌、31例腺癌及20例癌旁正常组织中WWOX基因蛋白的表达,并分析其与各临床病理指标之间的相关性.结果 WWOX基因在72.8%的非小细胞肺癌中失表达或表达减少,而在相邻正常肺组织中有80.0%正常表达.WWOX基因的表达与组织类型、细胞分化程度密切相关(P<0.05),在鳞癌和低分化癌中WWOX基因失表达或表达减少.结论 WWOX蛋白在非小细胞肺癌组织中呈低表达,该蛋白表达的缺失可能在不同类型非小细胞肺癌的形成中发挥了不同的作用. 相似文献
280.