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991.
992.
Hale JD; Valk PE; Watts JC; Kaufman L; Crooks LE; Higgins CB; Deconinck F 《Radiology》1985,157(3):727-733
Multisection, dual-echo magnetic resonance (MR) transaxial images of blood vessels contain both anatomic and qualitative information about flow. Even so, the images are produced as a series of two-dimensional tomographic sections from which full visualization of connected structures is difficult. A computer algorithm was developed that automatically detects flowing blood based on pixel intensity and calculated T2 and provides reconstructed views of vessels while analyzing and displaying flow characteristics. Images of abdominal vessels, aortic aneurysms, and the heart were encoded by flow and color to demonstrate depth. In addition, these data were reconstructed to derive a more accurate assessment of patency. With this technique, transaxial images can be used to analyze flow patterns, determine patent areas, and visualize all levels of vessels in a single image. 相似文献
993.
New antigenic variants of avian influenza A viruses 总被引:4,自引:0,他引:4
994.
The ultrasonic properties (velocity at 2·81 and 5·04 MHz, absorption in the range 1–15 MHz and vibration potential at 200 kHz) of amniotic liquid have been investigated. The results indicate that at physiological pH the absorption is essentially due to the proteins found in amniotic liquid, its vibration potential to the sodium chloride contained in this fluid while the velocity appears to be determined both by the proteins and sodium chloride. In the acid range (pH ~ 3) and alkaline range (pH ~ 9·6), proton transfer processes involving a low molecular weight component of amniotic liquid, in addition to those involving the proteins, contribute to the absorption of ultrasound by amniotic liquid. 相似文献
995.
996.
997.
A cohort study of the incidence of bronchial cancer in male workers in a small company producing chromate pigments is presented. Altogether 133 workers had been employed by the company from the time production was started in 1948 until the end of 1972. Workers with more than three years employment were included in the study, and three cases of bronchial carcinoma were found among the 24 workers who fulfilled this requirement. Based on the data of the Cancer Registry of Norway the risk of bronchial cancer for a corresponding group of the general population was found to be 0.079, which gives a risk ratio for exposed workers of approximately 38. The average age of the cancer patients was as low as 50 years at the time of diagnosis. All workers in the company had been exposed mainly to zinc chromate dust, and the exposure levels of the workers developing bronchial cancers had probably been from 0-5 to 1-5 mg Cr/m-3 for six to nine years. Two of the three patients were smokers. It is assumed that exposure to chromate pigments, and probably to zinc chromate, may be related to the increased incidence of bronchial cancer in this group of workers. The possibility of a contributing effect of tobacco smoking in at least two of the three cases cannot be ruled out. 相似文献
998.
H. Martin W. Spielmann Walther Stich W. Hunstein W. Lang R. Wolf D. Götze W. Mempel I. Boll 《Annals of hematology》1971,22(5):277-282
Ohne Zusammenfassung 相似文献
999.
J Lang 《The British journal of ophthalmology》1971,55(4):284-285
1000.
Maxwell M. Lang 《Clinical & experimental optometry》1975,58(8):311-312
The magnitude of near phorias and ductions is frequently a function of the type of instrumentation used for their measurement. Prismatic systems give readings which are consistently higher than those obtained with non-prismatic instruments. To some extent the differences may be due to the extreme forward position occupied by the Risley Prisms of some eye refractors. 相似文献