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71.
本文对校园网的教学应用范围、两种组成模式作了简要的介绍,指出校园网的快速建设和发展,对教学、科研、建立新的教学模式、改革教学内容、方法、推进素质教育等方面起到了积极重要的作用,离不开管理层观念的转变及长期支持。并对网络软件资源开发、建设、管理进行了建设性的讨论。 相似文献
72.
73.
L—盐酸赖氨酸对脑损伤大鼠胰高血糖素和血糖含量的影响 总被引:1,自引:0,他引:1
目的 研究 L盐酸赖氨酸对脑损伤后大鼠的胰高血糖素、胰岛素及血糖含量的影响。方法 采用落体法致大鼠脑损伤;伤后立刻一次腹腔注射 L盐酸赖氨酸,24h 后断头处死,用免疫组织化学 A B C 法结合图像分析技术,观察 L盐酸赖氨酸(621 .5mg·kg - 1 及310 .8mg·kg - 1) 对脑损伤后大鼠胰岛 A 细胞内胰高血糖素( Glu) 及 B 细胞内胰岛素( Ins) 免疫反应强度和光密度值的影响;用生化分析仪测定血糖含量。结果 L盐酸赖氨酸能显著增强 A 细胞内 Glu 免疫反应强度,提高平均光密度值,增加 Glu 的含量,并降低血糖水平,但对 B 细胞内 Ins 的免疫反应强度及光密度值无明显影响。结论 L盐酸赖氨酸可抑制 Glu 的释放并产生显著的降血糖作用。 相似文献
74.
True histiocytic lymphoma of the esophagus in an HIV-positive patient: an ultrastructural study 总被引:1,自引:0,他引:1
A 56-year-old white woman, seropositive for human immunodeficiency virus for 18 months without signs of acquired immunodeficiency syndrome, presented with retrosternal pain and progressive dysphagia secondary to an exophytic esophageal mass. Biopsies of the tumor showed a malignant neoplasm composed of pleomorphic, noncohesive cells growing in a diffuse, sheet-like fashion. Immunohistochemically, tumor cells were nonreactive with epithelial, lymphoid, neural, and monocyte/macrophage markers. Despite the noncontributory immunohistochemical findings, ultrastructural study of the tumor cells revealed convincing histiocytic features. Individual cells possessed long, slender filopodial projections, prominent Golgi apparatus, residual bodies, rare lysosomes, and prelysosomes. Immunoglobulin heavy chain and T-cell receptor gamma gene rearrangement studies detected no evidence of a clonal gene rearrangement. The patient responded poorly to chemotherapy and died 5 months after her initial symptom of dysphagia. 相似文献
75.
讨论了适用于面向对象软件质量的度量方法,提出了在Java软件质量度量中应注意的问题。 相似文献
76.
The current study investigated the effect of erbium filtration on an anteroposterior abdominal image. The radiation dose
reductions achieveable and the costeffectiveness of this filter were also evaluated. An assessment of the radiation dose delivered
employing either the standard total filtration (3 mm Al equivalent) or 0.1 mm of erbium filtration added to the standard filtration
was undertaken on 21 patients. Image quality was assessed using the Commission of European Communities (CEC) criteria. Significant
reductions of 64.6 % in entrance surface (p = 0.0001) and 23.4 % in effective dose (p = 0.0099) were recorded with erbium
filtration. Image quality was maintained and the cost per manSievert saved was £ 128. More widespread use of this dose reducing
filter is advocated.
Received: 7 August 1998; Revised: 19 February 1999; Accepted: 19 April 1999 相似文献
77.
Pretreatment of rats with the extract of Ginkgo biloba termed EGb761 reduced the behavioral sensitization induced by successive
-amphetamine administrations (0.5 mg/kg) as estimated by increasing values of locomotor activity. EGb761 pretreatment also prevented the reduced density of [3H]dexamethasone binding sites in the dentate gyrus and the CA1 hippocampal regions of
-amphetamine treated animals. These observations suggest that EGb761, by reducing glucocorticoid levels, could modulate the activity of the neuronal systems involved in the expression of the behavioral sensitization. 相似文献
78.
讨论了统计软件平台的概念,抽象描述了统计软件平台模型和统计软件平台体系结构,着重介绍了数据字典,统计分析和历史数据处理.采用层次支持的开放式软件结构,并综合统计事务中的各种统计需求设计统计软件平台,使实现的系统具有良好的动态可扩充性.中间件技术的应用使该平台能满足各种数据应用的特定需要.应用数据字典作为控制参数也使得该平台能够满足不同用户的统计要求. 相似文献
79.
The role of microcomputers in the analytical laboratory is growing rapidly as applications software becomes more generally available. In this survey, the impact of microcomputers on the practice of analysis in pharmaceutical and biomedical areas is examined in the context of available hardware. The advent of 16-bit microcomputers and the implications of computer access to networked data bases are also discussed. 相似文献
80.
Crister Ceberg Ingemar Larsson Sven-Erik Strand 《European journal of nuclear medicine and molecular imaging》1991,18(12):959-963
Characterization of the count-rate performance of scintillation cameras should include not only the specification of count losses. At high count rates, there is also an image distortion due to the mispositioning of pile-up events. In this paper a simple and clinically relevant procedure to quantify this distortion is presented. The images of a square uniform technetium-99m phantom at high and low count rates are used. The fraction of the total counts being correctly positioned is determined as the peripheral count density divided by the total average count density. This ratio, corrected for the camera non-uniformity at low count rates, is called the positioning ability. According to the National Electrical Manufacturers' Association (NEMA), the system count rate performance with scatter should be reported as the measured count rate giving 20% count losses. In this paper it is suggested that this measure be complemented by a measure of the fraction correct positioned events at this count rate. This fraction, the high count rate positioning ability', can be easily and accurately measured using our method. The method has been tested on two different scintillation cameras. For one of them the high count rate positioning ability was determined as 91% at a measured count rate of 30000 s–1 with 20% count losses. For the other camera, the corresponding figures were 88% at 59000 s–1 and close to 100% at 38000 s–1, before and after the installation of a new pile-up rejection circuit, respectively.
Offprint requests to: C. Ceberg 相似文献