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51.
52.
In an attempt to investigate the effect of ovulating hormone on the steroidogenesis of mature follicles in the course of ovulation, transitory changes of steroidogenesis in isolated rabbit follicles have been studied at several intervals after injection of an ovulatory dose of human chorionic gonadotropin (hCG). Five to ten follicles of approximately 1-2 mm in diameter were isolated from ovaries of a mature rabbit (2.5-3.0 kg) under streomicroscope, before and at the 3rd, 6th, 9th and 12th hours after intravenous injection of of 100 IU/kg of hCG. Follicles were incubated with 100 muCi of acetate-1-14C in 2 ml of Krebs-Ringer bicarbonate buffer (pH 7.4) at 37 degrees C for 3 hours under 95% oxygen plus 5% carbon dioxide. Each incubation was terminated by quick freezing and stored forzen at -20 degrees C until eighty follicles had been collected for each time period before commencement of analysis. Incorporation of radioactive acetate into pregnenolone, 17-hydroxypregnenolone, progesterone, 17-hydroxyprogesterone., 20 alpha-dihydroxyprogesterone, dehydroepiandrosterone, androstenedione, testosterone, estrone and estradiol-17beta were analysed by the reverse dilution technique and identified in radiochemically pure form by recrystallization to constant specific activities. The steroidogenic activity of the follicles was evaluated by overall as well as fractionated incorporations. A peak in the overall incorporation of 14C- acetate into the ten steroids at the 3rd hour after hCG injection, followed by gradual decrease up to the 9th hour was observed. The incorporation decreased markedly to a minimum level at the 12th hour after hCG injection, which was below the level of preinjection control. Comparable quantitative fluctuations were found with the fractionated incorporation of 14C-acetate into the C21 and C18 steroids in the time sequence following hCG injection. However, the fractionated incorporation into C19 steroids reached to a maximum at the 6th hour after hCG injection. 5istribution patterns of incorporation among the individual steroids were varied at each interval of time. In the non-injected control, mature follicles synthesized predominantly estradiol-17beta, testosterone and androstenedione. Divergent steroids were formed from radioactive acetate at the 3rd hour after hCG injection. These included porgestogen, androgen and estrogen, but pregnenolone and 17hydroxyprogesterone were the two principal steroids produced. There was no essential difference in the steroidogenic patterns between the 6th and 9th hour, the major products being C21 and C19 steroids such as pregnenolone, 17hydroxyprogesterone, dehydroipiandrosterone and testosterone. The three androgens were the major steroids formed at the 12th hour after hCG injection. Thus the chages in the steroidogenic profile of the follicle was obvious in the course of ovulation. The basis of qualitative changes in follicular steroidogenesis during the process of ovulation have been discussed in connection with an accompanying effect of an ovulatory dose of hCG. 相似文献
53.
5-Methyl-2-thiouridine (S) in tRNA-Met-f from an extreme thermophile is located in the TpsiC region, replacing T, and has a positive CD band centered at 310 nm. Upon heating, the profiles of the change in this band were similar to the UV melting profiles of the change monitored at 260 nm. This strongly suggests a close relation between heat denaturation of the tRNA and the conformation of the S base. Oligonucleotides containing S showed negative CD bands at 320-330 nm, like the monomer S itself, but when the 3'-2/5 fragment containing S formed a complex with the complementary 5'-3/5 fragment, a positive CD band appeared at 310 nm. These results suggest that combination of the TpsiC loop containing S with the hU loop is necessary for the positive band of S at 310 nm. S may serve to strengthen the association of the TpsiC loop with the hU loop in tRNA of the thermophile. 相似文献
54.
K Hashi K Fujitani S Kojima M Sakaguchi S Nishimura 《Canadian Metallurgical Quarterly》1976,4(9):903-910
A case of aneurysm of the great vein of Galen was reported in which craniotomy and clipping of a feeding artery arising from the left posterior cerebral artery was successfully performed. This 5-month-old girl developed progressive hydrocephalus from 2 months after birth. At 5 months the head circumference was 50 cm with tense enlarged fontanelle. Both eye balls were deviated downward. The deep tendon reflexes were hyperactive with bilateral ankle clonus and positive Babinski's sign. Mild cardiomegaly and hepatomegaly were also noted. Cerebral angiograms showed a large aneurysm of the great vein of Galen fed by a single enlarged arterial branch from the left posterior cerebral artery. After the evaluation of systemic circulatory status and under strict control of fluid transfusion craniotomy was performed. The feeding artery was clipped at its entrance to the aneurysm via left parieto-occipital interhemispheric approach. A rise in the mean arterial blood pressure of 20 mmHg was observed immediately following clipping. The postoperative course was satisfactory except for a left subdural fluid collection which required subduro-peritoneal shunt. The aneurysm was completely disappeared on the postoperative angiograms and the child is regaining the normal development. This is the first case of aneurysm of the great vein of Galen successfully operated in Japan. Clinical symptoms and signs, radiological features and operative treatment of the disease were reviewed from a total of 46 cases reported in the world literature. 相似文献
55.
Wind flows over the 8.2-m Subaru Telescope at Mauna Kea in Hawaii were analyzed with a correlation method. Three or four wind flows were detected from our measurements. Spatial and temporal resolution of the wind-flow analysis across the 8.2 m pupil were investigated experimentally. A three-dimensional spatiotemporal-frequency analysis was also applied to the wind-flow data. 相似文献
56.
By the agar-implantation developed by the authors the process of conversion on Blastomyces dermatitidis from mycelial phase to yeast phase was observed. First of all slide cultures of the fungus were prepared at room temperature. Upon confirmation of good hyphal growth, a cover glass was removed and a part of medium was cut out in a square of about 3 mm a side. After mice were laparotomied, each agar block cut out was implanted in the peritoneal cavity of mouse. The mice implanted with the agar blocks were killed, two each, every day for 14 days, and thereafter at intervals of a week for 2 months. Therefore, the implanted agar blocks were all recovered. They were examined directly by a light microscope with histopathological and electron microscopic examinations carried out at the same time. Within the peritoneal cavity of mouse, the intercalary and terminal chlamydospores were formed from hyphae. These subsequently swelled to become yeastlike cells and proliferated thereafter by budding. 相似文献
57.
A variable-pressure scanning electron microscopy (VP-SEM) with a cooling stage permits long hours of observation of water-containing specimens in their natural or close to natural state, without the conventional specimen preparations of fixation, dehydration, drying and metal coating. It reduces water vaporization and beam damage by keeping the specimens at a low temperature. We observed Bacillus cereus colonies on nutrient agar, which would shrink significantly if any conventional specimen preparation technique were used. We also studied the growing process of the bacteria on raw and steamed rice using the VP-SEM without conventional preparation techniques. Original specimens were directly mounted onto specimen holders and their backscattered electron images observed under the following conditions: specimen stage temperature, -10 degrees C; specimen chamber vacuum level, 30-70 Pa; and accelerating voltage, 15-20 kV. We recognized that the VP-SEM minimized deformation of the colonies due to shrinkage of the nutrient agar, and successfully imaged the morphology of the colonies and bacteria without a decline in bacteria number, which is apt to occur during fixation and dehydration. Also, the growth process of the bacteria on raw or steamed rice could be observed promptly, since there is no specimen preparation step. 相似文献
58.
Bidirectional Data Injection Operation of Hybrid Integrated SOA–MZI All-Optical Wavelength Converter
A bidirectional data signal input scheme of a semiconductor optical amplifier--Mach-Zehnder interferometer (SOA-MZI) wavelength converter was proposed and experimentally verified for a nonreturn-to-zero (NRZ)-format signal. Theoretical analyses reveal that it is possible to mitigate the patterning effect induced by cross-gain modulation (XGM) by utilizing the difference of the ratio between the XGM and cross-phase modulation on the injection directions of data signals. A hybrid integrated SOA-MZI all-optical wavelength converter, in which the coupling loss between the SOA and the silica waveguide was as small as 1 dB owing to a unique active alignment technique, was used for the experiment. We have verified the superior characteristics of the proposed operation scheme for the first time. Error-free wavelength-conversion operation for an NRZ signal at 40 Gb/s was confirmed 相似文献
59.
Al Amin A. Shimizu K. Takenaka M. Tanemura T. Inohara R. Nishimura K. Horiuchi Y. Usami M. Takita Y. Kai Y. Aoki Y. Onaka H. Miyazaki Y. Miyahara T. Hatta T. Motoshima K. Kagimoto T. Kurobe T. Kasukawa A. Arimoto H. Tsuji S. Uetsuka H. Nakano Y. 《Photonics Technology Letters, IEEE》2007,19(10):726-728
We report a bit-rate transparent optical burst switching (OBS) router prototype using a fast 5 times 5 PLZT [(Pb,La)(Zr,Ti)O3 ] optical matrix switch. Dynamic switching in a two-wavelength, 2 times 2 OBS switch is demonstrated. Contention resolution using a tunable Mach-Zehnder interferometer wavelength converter for both 40- and 10-Gb/s bursts is demonstrated for the first time. Error-free operation was achieved for both bit rates under the same settings, as required in autonomous networks 相似文献
60.
Shigekawa N. Nishimura K. Suemitsu T. Yokoyama H. Hohkawa K. 《Electron Device Letters, IEEE》2007,28(2):90-92
We proposed surface acoustic wave (SAW) filters composed of interdigital Schottky and ohmic contacts on AlGaN/GaN heterostructures. The contribution of the SAWs appeared in the radio frequency characteristics of the filters when the Schottky contacts were reverse biased. Onsets of the SAW signals and the threshold voltage of simultaneously fabricated high-electron mobility transistors were found to almost agree with one another. We also obtained an isolation of >40 dB. These results suggest that SAW-based functional devices are likely to be realized using AlGaN/GaN heterostructures with interdigital Schottky and ohmic contacts 相似文献