本文报道儿种体内外因素可诱导 El Tor 型霍乱弧菌产生 L 型。羧苄青霉素纸片法和倾注平板法可诱导 El Tor 型霍乱弧菌产生长丝体、圆球体和巨形体。El Tor 型霍乱弧菌分型噬菌体可诱导产生长丝体。El Tor 型霍乱弧菌陈旧肉汤培养物中...本文报道儿种体内外因素可诱导 El Tor 型霍乱弧菌产生 L 型。羧苄青霉素纸片法和倾注平板法可诱导 El Tor 型霍乱弧菌产生长丝体、圆球体和巨形体。El Tor 型霍乱弧菌分型噬菌体可诱导产生长丝体。El Tor 型霍乱弧菌陈旧肉汤培养物中可出现许多圆球体样物。上述因素诱导的 L 型均不稳定,很容易回复为原菌。作者还用鳝鱼和鲫鱼的胆汁诱导 El Tor 型霍乱弧菌形成稳定 L 型,并对 EL Tor 型霍乱弧菌 L 型的流行病学意义及其与霍乱弧菌越冬的关系进行了讨论。展开更多
针对磁阀可控电抗器(magnetic control reactor,MCR)产生谐波影响电网的问题,提出将MCR铁心设计成分级磁阀的结构。为此,从理论上比较单级和多级磁阀可控电抗器产生谐波的原理,推导出四级磁阀电抗器谐波电流的表达式,分析了电抗器在不...针对磁阀可控电抗器(magnetic control reactor,MCR)产生谐波影响电网的问题,提出将MCR铁心设计成分级磁阀的结构。为此,从理论上比较单级和多级磁阀可控电抗器产生谐波的原理,推导出四级磁阀电抗器谐波电流的表达式,分析了电抗器在不同工作状态下各饱和度之间的关系,对两种不同结构磁阀电抗器进行模拟仿真和试验数据对比,得出与理论分析基本吻合的结论,表明四级磁阀可控电抗器可大大减少总谐波含量。展开更多
The essential principles of the third theory of quantification are discussed, the concept and calculated method of reaction degree are put forward which extend the ap- plying range and scientificalness of the primary ...The essential principles of the third theory of quantification are discussed, the concept and calculated method of reaction degree are put forward which extend the ap- plying range and scientificalness of the primary reaction. Taking the Zhongmacun Mine as example, on the base of analyzing the rules of gas geology synthetically and travers- ing the geological factors infecting coal and gas outburst, the paper adopts the method of combining carving up statistical units with the third theory of quantification, screens out 8 sensitive geological factors from 11 geological indexes and carries through the work of gas geology regionalism to the exploited area of Zhongmacun according to the researching result. The practice shows that it is feasible to apply the third theory of quantification to gas geology, which offers a new thought to screen the sensitive geo- logical factors of gas outburst forecast.展开更多
OBJECTIVE： This work aims to observe the effects of electroacupuncture on brain-derived neuro- trophic factor （BDNF） mRNA expression in mouse hippocampus following cerebral ischemia-reperfu- sion injury. METHODS： ...OBJECTIVE： This work aims to observe the effects of electroacupuncture on brain-derived neuro- trophic factor （BDNF） mRNA expression in mouse hippocampus following cerebral ischemia-reperfu- sion injury. METHODS： The models of mouse cerebral isch- emia-reperfusion injury were established. A total of 96 healthy mice were randomly assigned into 4 groups, namely, the sham surgery, model, mod- el ＋ electroacupuncture, and mode ＋ hydergine groups. Mice in the model ＋ electroacupuncturegroup were treated through electroacupuncture at the Shenshu （BL 23）, Geshu （BL 17）, and Baihui （GV 20） acupoints. Mice in the model＋hydergine group were intragastrically administered with hy- dergine （0.77 mg/kg-1.day-l）. The levels of BDNF mRNA expressions in the hippocampus were ana- lyzed through a semi-quantitative reverse transcrip- tion-polymerase chain reaction assay on days 1 and 7 after the surgeries. RESULTS： BDNF mRNA expressions in the mouse hippocampus of the model group on days 1 and 7 after the surgery were higher than those of the sham surgery group （both P〈0.01）. On days 1 and 7 of the electroacupuncture treatment, BDNF mRNA expression in the mouse hippocampus of the mod- el ＋ electroacupuncture group was significantly ele- vated compared with the model group （both P〈 0.01） or the model ＋ hydergine group （both P〈 0.01）. On days 1 and 7 of the hydergine treatment, BDNF mRNA expression in the mouse hippocam- pus of the model ＋ hydergine group tended to in- crease compared with the model group; however, statistical significance was not achieved （both P〉 0.05）. CONCLUSION： Electroacupuncture treatment en- hances endogenous BDNF expression, which may improve the survival environment for intracerebral neurons and inhibit the apoptosis of hippocampal cells.展开更多
The reversibly red （R）/far-red （FR）-Iight-responsive phytochrome （phy） photosensory system initiates both the deetiolation process in dark-germinated seedlings upon first exposure to light, and the shade-avoidan...The reversibly red （R）/far-red （FR）-Iight-responsive phytochrome （phy） photosensory system initiates both the deetiolation process in dark-germinated seedlings upon first exposure to light, and the shade-avoidance process in fully deetiolated seedlings upon exposure to vegetational shade. The intracellular signaling pathway from the light-activated photoreceptor conformer （Pfr） to the transcriptional network that drives these responses involves direct, physical inter- action of Pfr with a small subfamily of bHLH transcription factors, termed Phy-lnteracting Factors （PIFs）, which induces rapid PIF proteolytic degradation. In addition, there is evidence of further complexity in light-grown seedlings, whereby phyB-PIF interaction reciprocally induces phyB degradation, in a mutually-negative, feedback-loop configuration. Here, to assess the relative contributions of these antagonistic activities to the net phenotypic readout in light-grown seedlings, we have examined the magnitude of the light- and simulated-shade-induced responses of a pentuple phyBpiflpif3pif4pif5 （phyBpifq） mutant and various multiple pif-mutant combinations. The data （1） reaffirm that phyB is the predominant, if not exclusive, photoreceptor imposing the inhibition of hypocotyl elongation in deetiolating seedlings in response to pro- longed continuous R irradiation and （2） show that the PIF quartet （PIF1, PIF3, PIF4, and PIF5） retain and exert a dual capacity to modulate hypocotyl elongation under these conditions, by concomitantly promoting cell elongation through intrinsic transcriptional-regulatory activity, and reducing phyB-inhibitory capacity through feedback-loop-induced phyB degrada- tion. In shade-exposed seedlings, immunoblot analysis shows that the shade-imposed reduction in Pfr levels induces increases in the abundance of PIF3, and mutant analysis indicates that PIF3 acts, in conjunction with PIF4 and PIF5, to promote the known shade-induced acceleration of hypocotyl elongation. Conversely, although the quadruple pifq mutant displays clearly reduced hypocotyl elongation compared to wild-type in response to prolonged shade, immunoblot analysis detects no elevation in phyB levels in the mutant seedlings compared to the wild-type during the majority of the shade-induced growth period, and phyB levels are not robustly correlated with the growth phenotype across the pif-mutant combinations compared. These results suggest that PIF feedback modulation of phyB abundance does not play a dominant role in modulating the magnitude of the PIF-promoted, shade-responsive phenotype under these conditions. In seedlings grown under diurnal light-dark cycles, the data show that FR-pulse-induced removal of Pfr at the beginning of the dark period （End-of-Day-FR （EOD-FR） treatment） results in longer hypocotyls relative to no EOD-FR treatment and that this effect is attenuated in the pif-mutant combinations tested. This result similarly indicates that the PIF quartet members are capable of intrinsically promoting hypocotyl cell elongation in light-grown plants, independently of the effects of PIF feedback modulation of photoactivated-phyB abundance.展开更多
文摘本文报道儿种体内外因素可诱导 El Tor 型霍乱弧菌产生 L 型。羧苄青霉素纸片法和倾注平板法可诱导 El Tor 型霍乱弧菌产生长丝体、圆球体和巨形体。El Tor 型霍乱弧菌分型噬菌体可诱导产生长丝体。El Tor 型霍乱弧菌陈旧肉汤培养物中可出现许多圆球体样物。上述因素诱导的 L 型均不稳定,很容易回复为原菌。作者还用鳝鱼和鲫鱼的胆汁诱导 El Tor 型霍乱弧菌形成稳定 L 型,并对 EL Tor 型霍乱弧菌 L 型的流行病学意义及其与霍乱弧菌越冬的关系进行了讨论。
文摘针对磁阀可控电抗器(magnetic control reactor,MCR)产生谐波影响电网的问题,提出将MCR铁心设计成分级磁阀的结构。为此,从理论上比较单级和多级磁阀可控电抗器产生谐波的原理,推导出四级磁阀电抗器谐波电流的表达式,分析了电抗器在不同工作状态下各饱和度之间的关系,对两种不同结构磁阀电抗器进行模拟仿真和试验数据对比,得出与理论分析基本吻合的结论,表明四级磁阀可控电抗器可大大减少总谐波含量。
基金Supported by"973"Key Foundation of China (2002CB211704).
文摘The essential principles of the third theory of quantification are discussed, the concept and calculated method of reaction degree are put forward which extend the ap- plying range and scientificalness of the primary reaction. Taking the Zhongmacun Mine as example, on the base of analyzing the rules of gas geology synthetically and travers- ing the geological factors infecting coal and gas outburst, the paper adopts the method of combining carving up statistical units with the third theory of quantification, screens out 8 sensitive geological factors from 11 geological indexes and carries through the work of gas geology regionalism to the exploited area of Zhongmacun according to the researching result. The practice shows that it is feasible to apply the third theory of quantification to gas geology, which offers a new thought to screen the sensitive geo- logical factors of gas outburst forecast.
基金Supported by Department of Science & Technology of He-bei Province (No. 06276102D-31)Department of Health of Hebei Province (No. 2005156)Training Program for Backbone of Scientific Research Talents of Hebei Medical University (2007)
文摘OBJECTIVE： This work aims to observe the effects of electroacupuncture on brain-derived neuro- trophic factor （BDNF） mRNA expression in mouse hippocampus following cerebral ischemia-reperfu- sion injury. METHODS： The models of mouse cerebral isch- emia-reperfusion injury were established. A total of 96 healthy mice were randomly assigned into 4 groups, namely, the sham surgery, model, mod- el ＋ electroacupuncture, and mode ＋ hydergine groups. Mice in the model ＋ electroacupuncturegroup were treated through electroacupuncture at the Shenshu （BL 23）, Geshu （BL 17）, and Baihui （GV 20） acupoints. Mice in the model＋hydergine group were intragastrically administered with hy- dergine （0.77 mg/kg-1.day-l）. The levels of BDNF mRNA expressions in the hippocampus were ana- lyzed through a semi-quantitative reverse transcrip- tion-polymerase chain reaction assay on days 1 and 7 after the surgeries. RESULTS： BDNF mRNA expressions in the mouse hippocampus of the model group on days 1 and 7 after the surgery were higher than those of the sham surgery group （both P〈0.01）. On days 1 and 7 of the electroacupuncture treatment, BDNF mRNA expression in the mouse hippocampus of the mod- el ＋ electroacupuncture group was significantly ele- vated compared with the model group （both P〈 0.01） or the model ＋ hydergine group （both P〈 0.01）. On days 1 and 7 of the hydergine treatment, BDNF mRNA expression in the mouse hippocam- pus of the model ＋ hydergine group tended to in- crease compared with the model group; however, statistical significance was not achieved （both P〉 0.05）. CONCLUSION： Electroacupuncture treatment en- hances endogenous BDNF expression, which may improve the survival environment for intracerebral neurons and inhibit the apoptosis of hippocampal cells.
文摘The reversibly red （R）/far-red （FR）-Iight-responsive phytochrome （phy） photosensory system initiates both the deetiolation process in dark-germinated seedlings upon first exposure to light, and the shade-avoidance process in fully deetiolated seedlings upon exposure to vegetational shade. The intracellular signaling pathway from the light-activated photoreceptor conformer （Pfr） to the transcriptional network that drives these responses involves direct, physical inter- action of Pfr with a small subfamily of bHLH transcription factors, termed Phy-lnteracting Factors （PIFs）, which induces rapid PIF proteolytic degradation. In addition, there is evidence of further complexity in light-grown seedlings, whereby phyB-PIF interaction reciprocally induces phyB degradation, in a mutually-negative, feedback-loop configuration. Here, to assess the relative contributions of these antagonistic activities to the net phenotypic readout in light-grown seedlings, we have examined the magnitude of the light- and simulated-shade-induced responses of a pentuple phyBpiflpif3pif4pif5 （phyBpifq） mutant and various multiple pif-mutant combinations. The data （1） reaffirm that phyB is the predominant, if not exclusive, photoreceptor imposing the inhibition of hypocotyl elongation in deetiolating seedlings in response to pro- longed continuous R irradiation and （2） show that the PIF quartet （PIF1, PIF3, PIF4, and PIF5） retain and exert a dual capacity to modulate hypocotyl elongation under these conditions, by concomitantly promoting cell elongation through intrinsic transcriptional-regulatory activity, and reducing phyB-inhibitory capacity through feedback-loop-induced phyB degrada- tion. In shade-exposed seedlings, immunoblot analysis shows that the shade-imposed reduction in Pfr levels induces increases in the abundance of PIF3, and mutant analysis indicates that PIF3 acts, in conjunction with PIF4 and PIF5, to promote the known shade-induced acceleration of hypocotyl elongation. Conversely, although the quadruple pifq mutant displays clearly reduced hypocotyl elongation compared to wild-type in response to prolonged shade, immunoblot analysis detects no elevation in phyB levels in the mutant seedlings compared to the wild-type during the majority of the shade-induced growth period, and phyB levels are not robustly correlated with the growth phenotype across the pif-mutant combinations compared. These results suggest that PIF feedback modulation of phyB abundance does not play a dominant role in modulating the magnitude of the PIF-promoted, shade-responsive phenotype under these conditions. In seedlings grown under diurnal light-dark cycles, the data show that FR-pulse-induced removal of Pfr at the beginning of the dark period （End-of-Day-FR （EOD-FR） treatment） results in longer hypocotyls relative to no EOD-FR treatment and that this effect is attenuated in the pif-mutant combinations tested. This result similarly indicates that the PIF quartet members are capable of intrinsically promoting hypocotyl cell elongation in light-grown plants, independently of the effects of PIF feedback modulation of photoactivated-phyB abundance.
