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991.
Previous studies have revealed that chromosome VI of saké yeasts is much larger than that of the other strains of Saccharomyces cerevisiae. Southern analysis using segments of chromosome VI of a laboratory strain as probes suggested that the nucleotide sequence of a major portion of this chromosome is conserved, but considerable diversity was found in the distal parts in the other strains. Physical maps also indicated that differences in length of chromosome VI were mainly due to differences in its ends. NotI was found to generate 9 kb and/or 16 kb fragments from the left telomere of chromosome VI in most saké yeasts, but no fragment in the case of AB972. SfiI produced one or two 30-50 kb fragments from the right end of this chromosome in all saké yeasts tested, but produced a 20 kb fragment in the case of AB972. All S. cerevisiae strains not employed in saké brewing were the same as AB972 in these respects. S. paradoxus had one NotI site in chromosome VI, while S. bayanus had two, one of which is possibly common to both species. The SfiI site mentioned above was present in chromosome VI of all species, while that of S. bayanus and S. paradoxus each had a second site distinct from the other. Chromosome VI of S. pastorianus was not distinguishable from that of S. bayanus.  相似文献   
992.
A fully depleted lean channel transistor (DELTA) with its gate incorporated into a new vertical ultrathin silicon-on-insulator (SOI) structure is presented. In the deep-submicrometer region, selective oxidation produces and isolates an ultrathin SOI MOSFET that has high crystalline quality, as good as that of conventional bulk single-crystal devices. Experiments and three-dimensional simulations have shown that this new gate structure has effective channel control and that the vertical ultrathin SOI structure provides superior device characteristics: reduction in short-channel effects, minimized subthreshold swing, and high transconductance  相似文献   
993.
The aim of this study was to compare the clinical efficacy and safety of low dose cyproterone acetate-estrogen combination (Diane) and the 5 alpha-reductase inhibitor finasteride in the treatment of hirsutism. Fourty-two women with hirsutism were included in the study. Twenty-one patients treated with cyproterone acetate (CPA) 2 mg and ethinyl estradiol (E) 35 micrograms daily on days 5-25 of the menstrual cycle, 21 with finasteride 5 mg daily. Hirsutism score, hormone levels, multiscreen blood chemistry and side effects were evaluated at three-monthly intervals for 9 months. A significant decrease in hirsutism score as compared to baseline was observed after 9 months with either CPA + E (Diane) (mean +/- SE, 15.81 +/- 1.19 vs 8.38 +/- 1.21) or finasteride treatment (17.81 +/- 1.05 vs 10.86 +/- 0.91) (p < 0.0005). The reductions in hirsutism scores (mean% +/- SE) were 14.23 +/- 2.29 vs 19.77 +/- 2.22 (p < 0.05) at 3, 40.23 +/- 4.58 vs 29.49 +/- 2.69 (p < 0.02) at 6 and 50.99 +/- 4.13 vs 39.87 +/- 3.30 (p < 0.02) at 9 months in CPA + E and finasteride groups, respectively. No significant changes were observed in hormone levels during finasteride treatment. Serum free testosterone significantly decreased at the third month of treatment, and remained suppressed for the duration of treatment in CPA + E group. DHEAS levels also decreased significantly after 6 and 9 months of therapy with CPA + E. SHBG significantly increased during CPA + E treatment. We conclude that both drugs are effective and well tolerated, but CPA + E appears to be more effective than 5 alpha-reductase inhibitor finasteride in long-term treatment of hirsute women. Diane is also a cost-effective drug.  相似文献   
994.
The excitatory effects of veratridine on slowly adapting pulmonary stretch receptors (SARs) were studied before and after administration of ouabain (a Na+-K+ ATPase inhibitor) in anesthetized, artificially ventilated rabbits after vagus nerve section. Administration of veratridine (40 microg/kg) stimulated SAR activity but did not significantly alter tracheal pressure. Administration of ouabain (50 microg/kg) initially stimulated SAR activity during both inflation and deflation, but after 20 min, two different types of SAR responses were observed; one became silent at the peak, of inflation only, and the other maintained excitatory activity during both inflation and deflation phases. Veratridine usually inhibited SAR activity in ouabain-treated animals, irrespective of the difference of ouabain effects. These results suggest that veratridine-induced stimulation of SARs is closely related to the change in the Na+ ion gradient, which is regulated by Na+ pump activity.  相似文献   
995.
The high-temperature piping and helium-to-helium intermediate heat exchanger of the High-Temperature Engineering Test Reactor (HTTR) are designed to be operating at very high temperatures of about 900°C among the class 1 components of the HTTR. At such a high temperature, mechanical strength of heat-resistant metallic materials is very low and thermal expansions of structural members are large. Therefore, innovative design methodologies are needed to reduce both mechanical and thermal loads acting on these components.To the HTTR, the design methodologies which can separate the heat-resistant function from the pressure-retaining functions and allow them to expand freely are applied to reduce pressure and thermal loads. Since these design methodologies need to verify their applicability, the Japan Atomic Energy Research Institute (JAERI) has been performing many design and research works on their verifications. The details of the design methodologies and their verifications are given in this paper.  相似文献   
996.
In the system ZrO2-CeO2, metastable t-ZrO2 solid solutions containing up to 30 mol% CeO2 crystallize at temperatures of 385–430 °C from amorphous materials prepared by the hydrazine method. Crystalline Ce3ZrO8 solid solutions are formed in as-prepared powders between 30–75 mol % CeO2. The variation of the lattice parameters of both solid solutions is determined as a function of CeO2 content. The value of the lattice parameter of pure Ce3ZrO8 (cubic) is a = 0.5342 nm. Detailed characterization of the Ce3ZrO8 powder has been performed. Crystallite size and particle size are strongly dependent on the heating temperature. Specific surface areas do not drop below 40 m2g–1 until the heating temperature is above 1000°C.  相似文献   
997.
We consider the problem of recognizing the driving environment of a vehicle by using information obtained from some sensors of the vehicle. Previously, we presented a recognition algorithm based on an usual method of pattern matching by use of fuzzy reasoning. Furthermore, this algorithm was extended to meet the demands of nonstandard drivers and changes of vehicle properties. In this algorithm we supposed that an extra source of knowledge (supervisor) for correcting the decision taken by the classifier could be acquired, and inevitably we expected additional sensors. To cover such weakness we present a self-supervised learning algorithm. Here the supervisor is constructed by using a-cut of the membership function of the representative class. Computer simulation on practical uses of the vehicle shows efficiency of the self-supervised learning  相似文献   
998.
Gastroesophageal reflux (GER) can develop in patients with esophageal achalasia either before treatment or following pneumatic dilatation or Heller myotomy. In this study we assessed the value of pre- and postoperative pH monitoring in identifying GER in patients with esophageal achalasia. Ambulatory pH monitoring was performed preoperatively in 40 patients with achalasia (18 untreated patients and 22 patients after pneumatic dilatation), 27 (68%) of whom complained of heartburn in addition to dysphagia (group A), and postoperatively in 18 of 51 patients who underwent a thoracoscopic (n=30) or laparoscopic (n=21) Heller myotomy (group B). The DeMeester reflux score was abnormal in 14 patients in group A, 13 of whom had been treated previously by pneumatic dilatation. Two types of pH tracings were seen: (1) GER in eight patients (7 of whom had undergone dilatation) and (2) pseudo-GER in six patients (all 6 of whom had undergone dilatation). Therefore 7 (32%) of 22 patients had abnormal GER after pneumatic dilatation. Postoperatively (group B) seven patients had abnormal GER (6 after thoracoscopic and 1 after laparoscopic myotomy). Six of the seven patients were asymptomatic. These findings show that (1) approximately one third of patients treated by pneumatic dilatation had GER; (2) symptoms were an unreliable index of the presence of abnormal GER, so pH monitoring must be performed in order to make this diagnosis; and (3) the preoperative detection of GER in patients with achalasia is important because it influences the choice of operation.  相似文献   
999.
High-Pressure Self-Combustion Sintering of Titanium Carbide   总被引:1,自引:0,他引:1  
A high-pressure self-combusiton sintering process has been applied to the synthesis and simultaneous sintering of titanium carbide. A dense titanium carbide compact was easily fabricated from the constituent elements without sintering aids under 3 GPa. The compact was composed of well-crystallized grains with a mean diameter of 20 μm at a molar ratio of C/Ti =0.95. The maximum values of the relative density and the Vickers microhardness were 96.5% and 31 GN/m2, respectively, at room temperature.  相似文献   
1000.
Many antibiotic resistance mutations arise in pathogenic bacteria that harbor plasmids (R-plasmids). Resistance to third generation cephalosporins, for instance, largely occurs by one or more point mutations in plasmid bla genes that expand the resistance spectrum of beta-lactamases. Here I review relevant evidence underlying the worldwide emergence of extended spectrum beta-lactamases (ESBLs). The conclusion reached is that the origin of these resistance-conferring mutations cannot be explained by a series of single point mutation and selection events. Instead, highly advantageous stochastic processes might exist that generate alterations in the sequence or the conformation of particular regions in chromosomal or plasmid genomes such as bla, i.e., recombination or mutation. Several explanations for the origin of ESBLs are reviewed but direct experimental evidence to support or to invalidate them is still lacking. The cellular conditions under which ESBLs arise are unknown; however, involvement of nutritional stresses inside natural animal hosts and of plasmid conjugal functions appear likely.  相似文献   
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