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241.
研究了通过计算机建立冶金能源信息库管理与能耗分析系统的相关问题。  相似文献   
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To efficiently perform morphological operations on neighborhood-processing-based parallel image computers, we need to decompose structuring elements larger than the neighborhood that can be directly handled into neighborhood subsets. In the special case that the structuring element is a convex polygon, there are known decomposition algorithms in the literature. In this paper, we give an algorithm for the optimal decomposition of arbitrarily shaped structuring elements, enabling an optimal implementation of morphological operations on neighborhood-connected parallel computers in the general case.  相似文献   
244.
We have synthesized a new compound, 3-bromoacetylamino benzoylurea (3-BAABU), which showed strong cancericidal activity by inducing irreversible mitotic arrest and subsequently apoptosis in human T cell leukemic cells (CEM), human biphenotypic leukemic cells (SP), a human prostate cancer cell line (PC-3), murine melanoma cells (B-16), and murine lymphoma/leukemia cells (EL4) in vitro with an ID50 in the range of 0.013-0.07 microg/ml (0.04-0.22 microM). Treatment of tumor cells for 12-24 h with 3-BAABU resulted in mitotic arrest at prometaphase/metaphase/anaphase, with separation and dispersion of chromosomes and with the absence of mitotic spindle apparatus in cytoplasm. Treatment with 3-BAABU had no cytotoxic and mitotic blocking effect in normal human lymphocytes, proliferating fibroblast cells (3T3), or proliferating myocardial cells (MOT). Cell cycle analyses showed that most treated leukemic cells accumulated at M phase 12 h after treatment. By the end of 48 h of treatment, the cells underwent apoptosis with DNA fragmentation. 3-BAABU inhibited the assembly of microtubules from tubulin but did not interfere with the disassembly of microtubules. The presence and the position of bromine and urea groups on the benzoic ring are the determining factors for its inhibition of microtubule assembly. Replacing bromine with chlorine yielded much less mitotic blocking activity and increased the ID50 40-fold. Substitution of the urea group with ethyl ester abrogated the activity of blocking mitosis but induced apoptosis. Moving the bromoacetylamino group from the 3-position to the 4-position removed blocking activity for mitosis but induced necrosis. These results suggest that 3-BAABU possesses a unique and functional structure and is a potential agent for cancer chemotherapy.  相似文献   
245.
Culture selected and expanded osteoblastic cells may be able to be reintroduced into massive skeletal defects to accelerate cell mediated regeneration of skeletal tissues, especially in bone ingrowth in total joint replacement, fracture healing, and osteoporosis. In vitro osteogenic cell culture is a useful model in studying the mechanism of bone metabolism under direct current stimulation. In this study, an osteoblastlike cell line was isolated from newborn rat calvaria. The osteogenic processes of the in vitro cultured cell line were studied by cytochemical, electron microscopic, and energy dispersive x-ray analysis techniques that resembled those observed in membrane bone ossification centers in vivo. Direct current stimulation of 100 microA/cm2 accelerated greatly the proliferation and calcification of the in vitro cultured cells. Intracellular free calcium ion metabolism was measured with an Adherent Cell Analysis and Sorting Machine. Under direct current stimulation, intracellular free calcium ion concentration increased an average of 2.3 times of the original level, which may play a key role in regulating osteogenesis and bone metabolism.  相似文献   
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247.
微波能在中药加工中的应用   总被引:2,自引:0,他引:2  
阐述了微波能烘干、灭菌在中药加工中的实例和一系列优点。  相似文献   
248.
We identified an expansion of the CAG trinucleotide repeat in the coding region of the Machado-Joseph disease gene in 7 of 24 American families diagnosed with autosomal dominant ataxia. All affected individuals were heterozygous for an expanded allele that ranged from 67 to more than 200 CAG repeats, whereas the normal allele had 14 to 33 repeats. In contrast to the Azorean-Portuguese origins of Machado-Joseph disease, the two largest American families were of German and Dutch-African descent. Clinical, pathologic, and genetic evaluations suggest that American families with spinocerebellar ataxia type 3 differ from those with Machado-Joseph disease by their ethnic origins, predominant spinopontine atrophy, lack of dystonic features, and larger CAG repeat expansion.  相似文献   
249.
刘江 《电子质量》1996,(1):23-24
介绍了UL试验室和中国检测机构的TPTDP合作计划。  相似文献   
250.
分析了全数字高清晰度电视(HDTV)中地面广播信道的干扰及抑制措施,给出了抑制同频干扰的梳状滤波器的设计方法和HDTV中8-VSB基本原理及传输方案,并基于传信率1/T=23.548Mbps的8-VSB作了计算机模拟。  相似文献   
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