排序方式: 共有948条查询结果,搜索用时 15 毫秒
171.
A peripheral neuropathy was produced in adult rats by placing loosely constrained ligature around the common sciatic nerve. At the ligature region of the nerve, demyelination developed. The postoperative behavior of these rats indicated that hyperalgesia and allodynia were produced. The electrical activity pattern of the damaged fibers was remarkably different from those of normal nerves: there were some abnormal spontaneous afferent firings from the injured fibers; multi-impulse responses of C-fiber to single shock was recorded; a lasting firing was elicited after the injured region was gently pressed or by oil drops at 40℃; an antidromic electric stimulus to the injured region, stimulations of L, sympathetic ganglion or systemic administration of noradrenalin, all caused an increase in on-goingspontaneous discharges of the injured fibers or brought the silent fibers into firing. Stimulation of the dorsal roots of the sciatic nerve produced no effect on their activities or caused a pause of the on-goi 相似文献
172.
173.
本文利用衰减全反射技术,采用棱镜-折射率匹配液-银膜-半导体掺杂玻璃结构,首次用非线性长程表面波实现了光学双稳态现象。所得到的反射率对入射光功率的曲线具有明显的滞后回线的形式。 相似文献
174.
Daihai Lake, located in NW margin of SE monsoon region, belongs to the sensitive area for climatic fluctuation. The analysis of continuous sedimentary column with an age of 100 ka indicates that there exists the different quasiperiodicity in time scales for monsoon shift. The climatic fluctuation in the Daihai Basin shows all along the alternation of cold and dry with a warm and wet climatic pattern, suggesting that the strength and drift of SE monsoon play a controllable role in the climatic change. 相似文献
175.
利用汞原子6~1S_0—7~1S_0双光子共振四波和频产生了125nm的相干辐射.对双光子共振增强效应、双光子共振克尔(Kerr)效应进行了研究.讨论了平面波和聚焦情况下最佳相位匹配的条件.实验中还观测到了四波参量振荡和四波差频的信号输出. 相似文献
176.
The capability of cytotrophoblast cells to produce hCG, progesterone, estrogen, cGnRH and β-endorphin in vitro has been demonstrated in serum-free culture medium. Before experiment, a 24-h preculture was carried out in order to remove the endogenous hormones of the tissue. During a period of 8 days' culture, the cytotrophoblast cells could constantly produce a small amount of hCG. The production of progesterone rose rapidly and became doubled within six days. The estrogen secretion showed a similar pattern in the presence of androstenedione, a precursor of estrogen, indicating the elevation of aromatase activity in the cells. The elevation of the enzyme activity has been further demonstrated not to be induced by androstenedione. In both cytotrophoblast and syncytiotrophoblast cell cultures, cGnRH was only detected in the culture of cytotrophoblast cells, with a value up to 4 pg/105 cells/24 h. However, β-endorphin was identified both in cytotrophoblast and syncytiotrophoblast cells. Its content increa 相似文献
177.
178.
Spiroplasma has been successfully isolated from the honey bee (Apis mellifera) and cultivated in R-2 medium in China. The isolate, CH-1 is obtained through triple cloning. CH-1 shows a helical morphology and a contractile movement. It is 0.17 μm in diameter and its length varies considerably with different growth periods. CH-1 forms granular-type and/or fried-egg-shaped colonies, 75—210 μm in diameter, on R-2 medium. It grows normally at temperatures ranging 25—35℃ (the optimum being 28—32℃). The optimal pH for growth is 7.0. The best growth occurs in medium containing 0.25 mol/L of sucrose. Under the optimal condition, its growth reaches the stationary phase 48 h after subculture. CH-1 cannot grow in serum-free medium and its growth is inhibited by digitonin. CH-1 can metabolize glucose, fructose, maltose, and trehalose. It can dehydrate arginine, CH-1 does not have an ability to utilize urea, nor dehydrate gelatin, nor reduce methylence blue. The taxonomic position of CH-1 has also been discuss 相似文献
179.
The title complexes were obtained by the reactions of bis(2,4-pentanedionato)oxovanadium VO(Acac)_2 and m-nitrophenylhydrazide m-NO_2PhCONHNH_2 in the media EtOH and MeOH respectively. The compound (Ⅰ) crystallizes in the space group PT with unit cell dimensions a=8.123(2), b=10.409(5), c=10.822(4), α=65.78(3)°, β=85.50(3)°,γ=89.04(3)°. The compound (Ⅱ) crystallizes in the space group P2_1/a with unit cell dimensions a=7.745(2), b=19.164(5), c=10.787(4), β=107.87(2)°. The resuhs of structural analyses show that the two compounds have the same characteristics: the tridentate ligand formed by condensation occupies three of the four equatorial positions of vanadium and the rest equatorial position is occupied by alkoxy group RO~-. As RO~-group also bridges the sixth coordinated position of each vanadium atom, it brings about the formation of the new type binuclear complexes of vanadium. 相似文献
180.
首次实验观察到在1064nm激光泵浦下掺Er~(3+)石英光纤中的共振增强受激四光子混频现象和光学自由感应衰减过程.在频域和时域上实验证明了Er~(3+)的~4I_(11/2)激发态能级对受激四光子混频产生的反斯托克斯谱线的增强效应. 相似文献