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1.
The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed. 相似文献
2.
Soren P. Lund Leif Simonsen Adolf S. Fries 《Basic & clinical pharmacology & toxicology》1995,76(1):36-40
Abstract: The effects of repeated exposure to 20 p.p.m. 4-tert-butyltoIuene (CAS No. [98-51-1]) 6 hr/day for 14 days on the function of the intact nervous system were examined by measurements of flash evoked potentials in Wistar rats. The exposure to 4-tert-butyltoluene induced changes in the amplitudes of the flash evoked potentials. The changes were significantly different from controls on day 2, 19 and 26 after cessation of the exposure, but not on day 5 and 12. No significant difference in body weight gain between groups was found during the experiment. These results indicate that repeated exposure to 20 p.p.m. 4-tert-butyltoluene causes persistent changes in the function of the central nervous system measured as changes in the flash evoked potential. A reevaluation of the present TLV-value of 10 p.p.m. for 4-tert-butyltoluene is suggested. 相似文献
3.
Hausegger KA; Cragg AH; Lammer J; Lafer M; Fluckiger F; Klein GE; Sternthal MH; Pilger E 《Radiology》1994,190(1):199
4.
At two scientific conferences in 1985, one in Copenhagen sponsored by the Nordic Council of Ministers and the World Health Organization (WHO), the other in Raleigh, NC, it was concluded that chronic toxic encephalopathy may develop following long-term occupational exposure to organic solvents (1,2). The terms organic affective syndrome, mild and severe chronic toxic encephalopathy were suggested for this condition describing increasing severity. In May 1990, a conference on organic solvents and the nervous system was held in Copenhagen sponsored by the Commission of the European Communities and the Danish Ministry of the Environment (3). Scientists and representatives from the governments, industries, and labour organisations from the EEC and US participated. 相似文献
5.
Focal liver lesions: characterization with triphasic spiral CT 总被引:15,自引:1,他引:14
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7.
Caserotti P Aagaard P Simonsen EB Puggaard L 《European journal of applied physiology》2001,84(3):206-212
Elderly people (age 75 years; n=48 males and 34 females) were studied in order to elucidate gender differences in elderly subjects on the determinants of
muscle power (force and velocity) during a stretch-shortening cycle. All subjects performed three maximal counter-movement
vertical jumps using both legs, on a force platform (Kistler 9281 B). The eccentric (Ep) and concentric (Cp) phases of the
jumps were analyzed. The Ep was further divided into an acceleration phase (Epacc: from the start of the downward movement to the maximal negative velocity) and deceleration phase (Epdec: from the maximal negative velocity to the end of the downward movement). Jump height for the men was higher than for the
women (P < 0.001). During both Epacc and Epdec no significant differences were observed between males and females in force and power generation. However, the men had a
higher peak muscle power during the Cp, which may be explained exclusively by the velocity determinant (P < 0.001). No specific gender-related strategy appeared to influence the motor pattern of the movement. The comparable eccentric
force generation of the leg extensors in both genders suggests a similar ability to cope with eccentric muscle actions during
everyday activities. In contrast, the marked lower capacity for concentric contractions in women may result in an impaired
performance, especially in activities where intense and rapid movements are essential, for example when reversing a forward
fall. This may be one reason why elderly women are more prone to falls than are elderly men.
Accepted: 19 September 2000 相似文献
8.
Metabolic adaptation of the chick embryo to chronic hypoxia 总被引:1,自引:0,他引:1
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