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108 tendons of the m. extensor hallucis longus were examined with a tensile testing machine within 36 h after death. The specimen were kept at a resting length of 20 mm. After the "steady state" was reached by cyclic loading, the tendons were stretched up to a maximum load of 18 kp, then deloaded to a certain level and after that the elongation was kept constant. At high loading level the tension of the tendon decreases with time (relaxation). At medium and low loading level the tension increases slightly (mechanical recovery). Between that two regions there is a certain load, where the tension will not change with time (isorheological point). The position of the isorheological point depends on the velocity of the elongation. At low velocity (2 mm/min) the isorheological point is situated at 70%, at high velocity (12 mm/min) at 60% of the maximum load. One will find the maximum relaxation, when no deloading occurs. The mechanical recovery, however, has its maximum at 5--25% of the maximum load. But when the tendon is totally deloaded, there seems to occur no recovery. The maximum relaxation is 5 to 6 times larger than the maximum recovery. Supposingly the relaxation- and recovery-processses will happen at the same time but with different intensity depending on the loading level. At least the relaxation-process consists of different relaxation components with different relaxation times. This will explain the phenomenon of a "secondary relaxation": After a long time of registration the recovery will turn into a slight relaxation. 相似文献
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WW Winkelmann 《Canadian Metallurgical Quarterly》1996,27(3):503-523
Today rotationplasty is well established as an acceptable procedure for limb salvage in patients who have a malignant tumor in the femur or tibia. The main indication is that it is the alternative to amputation. Rotationplasty should further be used in the very young child because of growth-dependent complications that can be expected after tumor resection and any kind of reconstruction. This article covers the classification of the different types of rotationplasties, the operative procedure, prosthetic care, and the functional results. 相似文献
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WW Fisher LG Bowman RH Thompson SA Contrucci L Burd G Alon 《Canadian Metallurgical Quarterly》1998,31(3):493-496
Transcutaneous electrical nerve stimulation is used to reduce pain but also may be useful for self-injurious behavior (SIB). In the current investigation, a microcurrent electromedical device, classified as a transcutaneous electrical nerve stimulator (TENS), was applied with a man with Down syndrome who displayed SIB that persisted in the absence of social contingencies. Although clinically significant results were not maintained, a clear difference in the rates of SIB during active and inactive TENS was observed. 相似文献
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Silicon - In this work, we emphasis on the Bismuth induced crystallization of hydrogenated amorphous silicon (a-Si) thin films. 50 nm of bismuth thin films are deposited by vapor... 相似文献
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Pronounced tremors were produced in unanesthetized cats following intracaudate (I.C.) injections of either d-amphetamine (15 mug), dl-methamphetamine (20 mug), l-amphetamine (48 mug) or 3-methoxytyramine (68-120 mug). Yet, a series of other chemically and pharmacologically related phenylethylamines, including dopamine (90 mug), were not tremorogenic even at substantially higher doses. The d-amphetamine tremors developed rapidly, failed to exhibit tachyphylaxis to repeated challenging doses (15 mug) and were not influenced by pretreatment with alpha-methyl-p-tyrosine. They also developed independently of local acetylcholine activity as evidenced by the inability of cholinergic antagonists (scopolamine and hemicholinium) to interfere with the tremors. Significant qualitative differences were found between the I.C. effects of d-amphetamine (15 mug) and dopamine (15-90 mug): d-amphetamine further increased the intensity of ongoing tremors induced by physostigmine (111 mug I.C.), whereas, dopamine readily inhibited the latter. When superimposed, I.C. dopamine was equally effective in suppressing d-amphetamine tremor activity. The results emphasize the selective tremorogenic actions of d-amphetamine and call attention to the contrasting stabilizing role of dopamine. This would suggest that two types of adrenergic receptor sites are operative in the caudate in neuroregulation of involuntary movements. 相似文献
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