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961.
The first VLSI digital signal processor that performs both high-precision image backprojection and spatial histogram calculations at raster-scan rates as high as 30 MHz is described. Realized in 1 μm CMOS technology, this 13.3 mm×13.3 mm chip is designed to handle images as large as 1024×1024 12 b pixels. Loadable coefficients and a unified architecture allow this IC to be used with a variety of computed-tomography scanners for image reconstructions, including fan- and parallel-beam reconstruction. This chip also computes the forward Radon transform, which is a spatial histogram, permitting it to be used for iterative reconstruction algorithms. The bit lengths in the fixed-point architecture assure 12 b reconstruction accuracy 相似文献
962.
Y Yonemura H Kimura S Fushida K Tugawa Y Nakai M Kaji L Fonseca A Yamaguchi I Miyazaki 《Canadian Metallurgical Quarterly》1993,71(8):2448-2453
BACKGROUND: Proliferative activities of tumors are thought to be prognostic features of malignant tumors, but their value as measured by proliferating cell nuclear antigen (PCNA) labeling remains unclear in gastric cancer. METHODS: PCNA labeling rates (LR) were quantified in 121 paraffin-embedded biopsy specimens from primary tumors by immunocytochemistry. RESULTS: Immunohistochemical analyses have demonstrated that PCNA presents an intense staining in the nuclei of tumor cells and mucous neck cells of gastric glands. The PCNA LR ranged from 12% to 79% (mean +/- standard deviation), and a significant correlation was found between bromodeoxyuridine labeling indices and PCNA LR: PCNA LR were closely associated with tumor size, serosal invasion, and nodal involvement. The patients with tumors with high PCNA LR (greater than 40%) were dead significantly earlier than were those with tumors with low PCNA LR: When the PCNA LR and all the clinicopathologic parameters were entered into a Cox regression model, PCNA LR emerged as an independent prognostic factor. CONCLUSION: These results indicate that PCNA LR may be a potentially useful prognostic factor for gastric cancer. 相似文献
963.
The photosensitizing properties of p-nitroacetophenone (PNAP), a well-known radiosensitizer, have been studied in near UV region. The mechanism of PNAP photosensitization has been investigated by testing the efficiency of singlet oxygen production using photooxidation of 2,2,6,6-tetramethylpiperidine (TEMP) and photodegradation of guanosine. In both the cases, the enhancement effect of deuterated solvents has been observed. Results of these experiments suggest the significant role of type II mechanisms in PNAP photosensitization. 相似文献
964.
Comments that L. B. Silverstein's (see record 1992-05293-001) article on child care and maternal employment contributes unfounded and damaging misbeliefs regarding fathers. The dad-as-cad myth suggests intentional malevolence or at least blatant failure by fathers to care for others, and suggests that their failure to share equally in child care and household management is the primary cause of marital conflict. W. B. Johnson and D. Hayes propose a research agenda for fathering that originates in a coherent model of male development in the context of ever-changing environmental demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
965.
The Munich Community Health Service (Medical School-Service Department) conducted an alcohol prevention project in ten public secondary schools. The 423 pupils (11-17 years of age) filled in a questionnaire on alcohol and discussed it afterwards under the guidance of a school physician and a teacher using guideline information. The results of the survey are presented in this paper. Additionally, suggestions for transferring the results to conceptualize and carry out preventive measures are made. The results indicate that the first experience with alcohol occurred early in life. One-fifth of the sample had already tried alcohol at the age of six. Immediate effects of alcohol (e.g. state of drunkenness) were experienced by 35.7 percent of the sample group. Kiosks, shops, and beverage stores were named most frequently as sources for alcohol. The sources of social support varied with respect to sex and age. With increasing age of the children, parents were contacted less frequently whereas the role of peers increased. The present results supply possible paths of action for the development of successful prevention strategies, e.g. by pointing out the early age of onset as well as specific sources of alcohol acquisition. 相似文献
966.
967.
Two cases of congenital trabecular hypoplasia of the right ventricle are reported. In the first, the neonatal diagnosis was missed and the child did well until the 13th month of life when a modified Blalock-Taussig shunt was done because of increasing cyanosis. Outcome was good until the 4th year of life when symptomatic atrioventricular block was detected in an emergency situation. A bidirectional Glenn anastomosis and pacemaker implantation were successfully carried out after clinical establization and the child is doing well up to now. The second case presents the disease with its worst features: severe cyanosis and acidosis in the first day of life. A modified Blalock-Taussig shunt was performed and death occurred soon after the operation. 相似文献
968.
969.
Cortical implants for the blind 总被引:4,自引:0,他引:4
Arrays of stimulating electrodes can be placed in the brain itself, in the visual cortex, to bring vision to the profoundly blind. However, when designing such devices one needs to take into consideration the fact that the visual pathway maps images onto cortical structures in a complex and unpredictable way 相似文献
970.