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81.
We investigated the effects of castration and progesterone administration on the three gonadotropin-releasing hormone (GnRH)-encoding mRNAs in sexually mature male tilapia Oreochromis niloticus. In situ hybridization histochemistry was performed using 35S-labeled antisense oligonucleotide probes complementary to salmon-, seabream-, and chicken II-GnRH cDNAs to quantify cellular GnRH mRNA expression in the terminal nerve ganglia (nucleus olfactoretinalis), preoptic area, and midbrain tegmentum of animals castrated for 2 weeks and injected intraperitoneally with sesame oil or progesterone. Castration significantly elevated salmon-GnRH mRNA but not seabream- or chicken II-GnRH mRNA levels. Progesterone treatment had no effect on salmon-, seabream-, or chicken II-GnRH mRNA levels. Comparisons between intact, castrated, and progesterone-treated animals showed no change in the total volume of nucleus olfactoretinalis, cell sizes, and total numbers of cells expressing GnRH mRNA within the midbrain and preoptic area. These results demonstrate that salmon-GnRH but not seabream- or chicken II-GnRH-synthesizing neurons are under a gonadal steroid negative feedback control and that progesterone might not be the main hormone regulating the three GnRH-encoding mRNAs in the male tilapia. 相似文献
82.
One difficulty in analyzing the state of filament in the dry spinning process is that in the boundary conditions required to solve the equations of mass, momentum and energy which are derived on the consideration of balance with respect to infinitesimally small element are not given a priori. The equations which include these boundary conditions in themselves are derived by considering mass, momentum, and energy balances with respect to the entire cross section of filament. These additional macroscopic equations are simplified to a great extent by assuming the flat velocity profile through the cross section of filament. Besides, in the steady state, these macroscopic equations are modified to give the equations of average solvent content, spinning tension, cross-sectional area, and average temperature. When the spinning conditions are given and the physical constants are measured for a given polymer and solvent system, it becomes possible to calculate the state of filament by solving these microscopic and macroscopic equations simultaneously without resorting to actual spinning. 相似文献
83.
Iwaguchi S Suzuki M Sakai N Nakagawa Y Magee PT Suzuki T 《Yeast (Chichester, England)》2004,21(8):619-634
Electrophoretic karyotype studies have shown that clinical isolates of Candida albicans have extensive chromosome length polymorphisms. Chromosome translocation is one of the causes of karyotypic variation. Chromosome translocation events have been shown to occur very frequently at or near the major repeat sequence (MRS) on chromosomes. The MRS consists of the repeated sequences RB2, RPS and HOK, and the repeated sequences are considered to be the template for recombination. To investigate which element of the MRS is important for chromosome translocation, we constructed three cassettes, each containing a URA blaster and sequences homologous to one of the repeats, for insertion into the MRS region on the chromosomes. The ura3 strain STN22u2, which shows a stable, standard karyotype, was transformed with each construct. Insertion events with each cassette occurred at almost all chromosomes. Insertion into the RB2 repeat, but not into the RPS repeat, was accompanied by chromosome translocation in some transformants: chromosome translocations between chromosomes R and 7 and chromosomes 1 and 7 were found, as well as deletions of 7A and 7C from chromosome 7. We conclude that the insertion at the RB2 region may initiate chromosome translocation in C. albicans. 相似文献
84.
Diversity control in ant colony optimization 总被引:1,自引:0,他引:1
Optimization inspired by cooperative food retrieval in ants has been unexpectedly successful and has been known as ant colony
optimization (ACO) in recent years. One of the most important factors to improve the performance of the ACO algorithms is
the complex trade-off between intensification and diversification. This article investigates the effects of controlling the
diversity by adopting a simple mechanism for random selection in ACO. The results of computer experiments have shown that
it can generate better solutions stably for the traveling salesmen problem than ASrank which is known as one of the newest and best ACO algorithms by utilizing two types of diversity. 相似文献
85.
We have studied the cathodoluminescence of AlxGa1-xAs/GaAs multilayers grown on ridge-type triangles by molecular beam epitaxy. The compositional variation of Al, as well as the distribution of impurity and/or defect, was revealed by variations in the cathodoluminescence spectra and images. The Al composition in an AlxGa1-xAs layer was highest in the (111)A facet and decreased in the order (100), (411)A, (111)-delta and (110) facets. On the other hand, the carbon concentration was highest in the (411)A facet and decreased in the order (111)A, (111)-delta, (100) and (110) facets. It should be noted that the (111)-delta facet has a significant effect on the redistribution of Al. Although our ridge-type triangles are rather large for the quantum structures, these data have elucidated the self-organization mechanism of the AlxGa1-xAs/GaAs system and have yielded information on the design of quantum structures. We conclude that cathodoluminescence observation is a powerful tool for studying the compositional variation or band structure of three-dimensional microscale or nanoscale construction. 相似文献
86.
Hiromi?YoshidaEmail author Kyoko?Matsuda Yuki?Hirakawa Yoshiyuki?Mizushina 《Journal of the American Oil Chemists' Society》2003,80(7):665-674
To clarify the effects of microwave roasting on the distribution of tocopherols and FA of phospholipids within soybeans, whole
soybeans (Glycine max) were treated by microwave and further evaluted as compared to a raw sample. Tocopherol homologs, measured using HPLC, and
phospholipid profiles, quantified with GC, were determined in the seed coat, the embryonic axis, and selections of cotyledons
separated from three cultivars. The tocopherols were predominantly detected in the axis, followed by the cotyledons, and then
very little in the coat. As much as 25% of the individual tocopherols originally present in the coat were lost at 12 min of
roasting, whereas <25% was lost in the cotyledons and the axis after 20 min of roasting. The greatest rate of phospholipid
loss (P<0.05) was observed in PE, followed by PC and PI, and their changing patterns were more pronounced in the coat than in the
cotyledons or the axis. Thus, tocopherol content and phospholipid profiles change with microwave roasting according to tissue. 相似文献
87.
Transparent conducting SnO2 powders doped with 10% Fe content were prepared by a polymerized complex method under acidic solutions, and annealed finally at 550 °C, and at 600 °C. These samples were characterized by X-ray diffraction, magnetization, and Mössbauer spectrometry at room temperature. Rutile SnO2 phase was obtained for both samples, and the crystallite sizes were in the range of 13-14 nm. Both samples exhibit magnetization and the saturation magnetization was smaller for the sample annealed at 600 °C than for sample annealed at 550 °C. Room temperature Mössbauer spectra for both samples showed the presence of two different paramagnetic iron sites but no magnetic sextets. These results suggest that ferromagnetism originates from magnetic defects and not directly from iron ions. 相似文献
88.
Yusuke Kusuda Kinya Fukuda Masao Matsumura Kazuhisa Hagisawa Gaku Okamoto Tatsuo Nakanishi Yoshiyuki Inoue 《Electrical Engineering in Japan》2007,159(4):18-26
Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF6 gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF6 gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511 相似文献
89.
90.
Mikio Fukuhara Yoshiyuki Kuwano Kiyoshi Saito Taiji Hirasawa Ichiro Komura 《NDT & E International》1998,31(3):211-216
The degree of fatigue in ferritic wrought steel during cyclic bending was determined by analysis of diffracted SH ultrasonic waves with the aid of multiple regression analysis. As the degree of fatigue increases, accompanied by residual stress, the incident waves curve to the interior region with positive stress field owing to the acoustoelastic effect. As a result, the propagation time of the launched waves lengthens, leading to a modulation of the received waveform. Multiple regression analysis for the waveform modulation produces a reliable estimation, with correlation coefficient of 0.948, for the degree of fatigue. 相似文献