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21.
Laparoscopic retroperitoneal lymph node dissection is a new surgical procedure used to enhance staging in men with clinical stage I nonseminomatous germ cell tumors of the testis. The procedure has been performed in a limited number of patients at several centers with extensive laparoscopic experience. Laparoscopic retroperitoneal lymphadenectomy is a technically demanding procedure which can be successfully completed in the majority of patients. However, the risk of complications is greater than in patients who undergo standard open retroperitoneal lymph node dissection. The primary advantage of a laparoscopic approach is shortened hospitalization and rapid return to normal activity. The role of laparoscopy in the management of patients with testis malignancy has not been defined. The use of this staging procedure may help minimize the need for surveillance studies following surgery and may be best utilized in men with a lower likelihood of nodal metastases. Ultimately, prospective study in large groups of patients will be necessary to determine the role of laparoscopic retroperitoneal lymph node dissection in patients with testis cancer.  相似文献   
22.
The use of capillary electrophoresis (CE) for clinically relevant assays is attractive since it often presents many advantages over contemporary methods. The small-diameter tubing that holds the separation medium has led to the development of multicapillary instruments, and simultaneous sample analysis. Furthermore, CE is compatible with a wide range of detectors, including UV-Vis, fluorescence, laser-induced fluorescence, electrochemistry, mass spectrometry, radiometric, and more recently nuclear magnetic resonance, and laser-induced circular dichroism systems. Selection of an appropriate detector can yield highly specific analyte detection with good mass sensitivity. Another attractive feature of CE is the low consumption of sample and reagents. However, it is paradoxical that this advantage also leads to severe limitation, namely poor concentration sensitivity. Often high analyte concentrations are required in order to have injection of sufficient material for detection. In this regard, a series of devices that are broadly termed 'analyte concentrators' have been developed for analyte preconcentration on-line with the CE capillary. These devices have been used primarily for non-specific analyte preconcentration using packing material of the C18 type. Alternatively, the use of very specific antibody-containing cartridges and enzyme-immobilized microreactors have been demonstrated. In the current report, we review the likely impact of the technology of capillary electrophoresis and the role of the CE analyte concentrator-microreactor on the analysis of biomolecules, present on complex matrices, in a clinical laboratory. Specific examples of the direct analysis of physiologically-derived fluids and microdialysates are presented, and a personal view of the future of CE in the clinical environment is given.  相似文献   
23.
张荣  曲宏伟 《微电子学》1998,28(6):437-439
制作压力传感器时,在二氧化硅层上淀积多晶硅膜,既可利用优良的机械特性,又可保证压敏电阻与衬底间具有良好的绝缘性,由此可大大提高器件的温度特性。介绍了一种多晶硅压力传感器的原理和设计。实验结果表明,这类传感器具有灵敏度好,精度高等特点,电路工作范围为0-250℃,且具有良好的温度稳定性。  相似文献   
24.
Applies the technique of parallel processing to concept learning. A parallel version-space learning algorithm based upon the principle of divide-and-conquer is proposed. Its time complexity is analyzed to be O(k log2n) with n processors, where n is the number of given training instances and k is a coefficient depending on the application domains. For a bounded number of processors in real situations, a modified parallel learning algorithm is then proposed. Experimental results are then performed on a real learning problem, showing that our parallel learning algorithm works, and being quite consistent with the results of theoretical analysis. We conclude that when the number of training instances is large, it is worth learning in parallel because of its faster execution  相似文献   
25.
干燥装置是一类重要的化工设备。本文概要介绍国外开发的新型干燥设备及其原理、特点、应用。  相似文献   
26.
甲醇氧化羰化制碳酸二甲酯产物气相色谱分析   总被引:6,自引:1,他引:5  
以Chromosorb 10 1为固定相 ,气相色谱法分析甲醇氧化羰化制碳酸二甲酯产物中水、甲醇、乙酸甲酯和碳酸二甲酯等组份的含量 ,考察了柱温 ,载气流量对分离度的影响 ,确定了适宜的分析条件 ,并用校正面积归一化法定量。该方法操作简便 ,快速 ,精度高 ,重现性好  相似文献   
27.
环境中氚和碳-14   总被引:4,自引:0,他引:4  
方栋  李红 《辐射防护》2002,22(1):51-56
本文介绍了加拿大恰克河实验室有关氚和碳-14在环境中行为和评价的研究。  相似文献   
28.
In this letter, a concise process technology is proposed for the first time to enable the fabrication of good quality three-dimensional (3-D) suspended radio frequency (RF) micro-inductors on bulk silicon, without utilizing the lithography process on sidewall and trench-bottom patterning. Samples were fabricated to demonstrate the applicability of the proposed process technology.  相似文献   
29.
讨论了如何选择适当的规则,如何建立简洁实用的规则库,如何应用规则库.提出了四种主要的光学邻近矫正规则,在实验结果中列举了规则库中的部分数据.利用规则矫正后的版图光刻得到的硅片图形有了明显的改善.规则库的自动建立部分 (OPCL)是基于规则的光学邻近矫正系统的重要组成部分.  相似文献   
30.
In this paper, a localized MEI method (L-MEI) is developed and combined with the domain decomposition method (DDM) for the simulation of scattering by a concave cylinder. In the L-MEI, the whole domain is decomposed into many subdomains. Different from the conventional MEI method, the MEI coefficients of the L-MEI method in each subdomain are only dependent on the localized metrons that are defined in the subdomain. The localization of metrons has the following advantages: (1) speeding up the calculation of MEI coefficients and saving memory, (2) making the MEI method available for concave structures, and (3) obtaining a band sparse matrix directly without any modification  相似文献   
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