Aim: To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate (TU) treatment. Methods: Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 day...Aim: To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate (TU) treatment. Methods: Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 days for 130 days. The numbers of all types of cells (nuclei) in the seminiferous tubules and the interstitial tissue were estimated using a contemporary stereological tool, the optical disector. Results: In response to TU treatment, the numbers of non-type B spermatogonia, type B spermatogonia and late elongated spermatids per testis were reduced to 51 %, 66 % and 14 % of the controls, respectively. The conversion ratios from type B spermatogonia to early spermatocytes and pachytene spermatocytes were not significantly affected and the ratios to the later germ cell types fell to 51 % - 65 % of the controls. Less than 1.0 % of immature round spermatids were seen sloughing into the tubule lumen, 4.0 % of elongated spermatids retained in the seminiferous epithelium, and about half of the elongated spermatid nuclei appreciably malformed. Leydig cells were atrophied but their number and the peritubular myoid cell number per testis were unchanged. Conclusion: Double inhibition of spermatogenesis (i.e. inhibition at spermiation and spermatogonial conversion to type B spermatogonia), a scenario seen in the monkey and human following gona-dotrophin withdrawal, was not sufficiently effective for a complete spermatogenic suppression in the rat after TU treatment, probably due to ineffective inhibition of the Leydig cell population and therefore the intra-testicular testosterone levels.展开更多
In the cross between B. napus with OguCMSOrychophragmus violaceus, pre-fertilizatiocompatibility was observed. An intergeneric hybrid was successfully obtained by usinovary culture. The hybrid status was confirmed by ...In the cross between B. napus with OguCMSOrychophragmus violaceus, pre-fertilizatiocompatibility was observed. An intergeneric hybrid was successfully obtained by usinovary culture. The hybrid status was confirmed by cytology, morphology, fertilityisozyme and miosis analysis. The seed setting rate was 0.0072%. An amphidiploid of thhybrid was also produced by the use of chromosome-doubling method with 0.1% colchicinetreatment. Obtaining this hybrid and its amphidiploid has important theoretical anutilization value.展开更多
The effects of graphite granularity on the properties of low carbon MgO-C based materials have been investigated in the work. Large crystal fused magnesia, natural flake graphite with different particle sizes and anti...The effects of graphite granularity on the properties of low carbon MgO-C based materials have been investigated in the work. Large crystal fused magnesia, natural flake graphite with different particle sizes and anti-oxidant were adopted as raw material for preparation of specimens. However, the results show that the physical properties, oxidation resistance and thermal shock resistance of low carbon MgO-C materials with content of 4.0wt% graphite are improved obviously through the use of special and suitable size graphite. The excellent performance achieved was considered as a result of microstructure modification of MgO-C materials. Therefore, it is suggested that both fine and micro grade natural flake graphite used for production of low carbon MgO-C bricks.展开更多
The flowering phenology, pollination ecology and breeding system of Caesa/pinia crista L.were studied in Dinghushan Nature Reserve, Guangdong, China. The species started blooming in Februaryor March, then last till la...The flowering phenology, pollination ecology and breeding system of Caesa/pinia crista L.were studied in Dinghushan Nature Reserve, Guangdong, China. The species started blooming in Februaryor March, then last till late April. It took about one week from first flower appearance to its full blooming,which lasted for 2-4 d. The pollen-ovule ratio was 18 000~500. The breeding system was self-incompatible,and protogynous xenogamy. Hymenoptera constituted the major group of pollinators. The pollination typeis ambophily, the species could be pollinated by wind if the pollinators were unavailable: this is the firstrecord of ambophily in the genus Caesalpinia. The floral structure adaptation to the pollinating behavior ofcarpenter bees was described. The influences of artificial treatments in pollination biological studies onthe flowering and fruiting of the plants were also discussed.展开更多
Computer aided design of heat treatment for AISI P20 mold steel with good machinability is attempted to proceed by the commercial software package Thermo-Calc (TCP+DICTRA). Through experimental and theoretical analysi...Computer aided design of heat treatment for AISI P20 mold steel with good machinability is attempted to proceed by the commercial software package Thermo-Calc (TCP+DICTRA). Through experimental and theoretical analysis of phase transformation during heat treatment, further knowledge of designing proper heat treatment is obtained. Then the machinability of AISI P20+Ni steel under given heat treatment condition is studied and the influencing factors to their machinability are analyzed. It is shown that heat treatment designed by computer simulation of carbide transformation is applicable to AISI P20+Ni steel with good machinability; AISI P20+Ni steel with tempered sorbite treated by quenching & tempering has optimal machinability; normalizing at the temperature of 910°C & tempering can avoid cracking and result in acceptable machinability in small thickness module.展开更多
Thermo-Calc software package (TCP+DICTRA) was used to simulate the carbide transformation process in die steel for plastic. Combined with TEM analysis, the calculated result confirms that the carbide in equilibrium st...Thermo-Calc software package (TCP+DICTRA) was used to simulate the carbide transformation process in die steel for plastic. Combined with TEM analysis, the calculated result confirms that the carbide in equilibrium state is M_7C_3 carbide. The dissolution of M_7C_3 carbide in steel is predicted by DICTRA program. It was shown that the temperature remarkably affects the dissolution process of M_7C_3 carbide, but the influence of alloy elements such as manganese and molybdenum can be neglected in this steel.展开更多
Education informatization plays an increasingly prominent supporting and leading role in education reform and development. Currently, accelerating education informatization still faces many difficulties and problems. ...Education informatization plays an increasingly prominent supporting and leading role in education reform and development. Currently, accelerating education informatization still faces many difficulties and problems. Compared with the requirements of the CPC Central Committee and the State Council, and compared with the level of deep application and integration innovation in developed countries, there are still gaps and many problems. At present, cloud computing, big data, Internet of Things, mobile computing and other new technologies are gradually widely used, the pace of informatization in all sectors of the economy and society is accelerating, the overall level of informatization in society is deepening, and the revolutionary impact of information technology on education is becoming increasingly obvious. Under the general trend of such technology, the cloud platform of comprehensive business based on cloud computing technology will be planned and built in an overall way to provide strong support for medical teaching, scientific research, innovation and development of faculty and students of the university. The integrated business platform provides cloud services such as standard IT infrastructure, student training platform, medical teaching and research, scientific research and development, and "entrepreneurship and innovation". Students and teachers can access and use IT at any time through the network. The content of each service can be customized and expanded according to the requirements of teachers and students. With the promotion of the service, the audience can be extended from teachers and students to users outside the school.展开更多
sST2 is one of the members of interleukin-1 receptor family. When the myocardium is excessively pulled, sST2 and ST2L competitively bind IL-33, reducing the IL-33/ST2L signal pathway, which leads to accelerated myocar...sST2 is one of the members of interleukin-1 receptor family. When the myocardium is excessively pulled, sST2 and ST2L competitively bind IL-33, reducing the IL-33/ST2L signal pathway, which leads to accelerated myocardial remodeling and ventricular dysfunction. Unlike natriuretic peptide, sST2 is almost unaffected by age, gender, race, BMI, etiology of heart failure, atrial fibrillation, anemia, kidney function and other factors. At present, sST2 has played an important role in the diagnosis, prognosis and risk stratification of heart failure. With the deepening of clinical research, the application value of sST2 in other cardiovascular diseases needs further discussion. In addition, patients with metabolic syndrome and other diseases that affect myocardial metabolism and myocardial remodeling can consider to further assess the severity of the disease by measuring the concentration of sST2 and dynamically monitoring it.展开更多
New technologies, such as 5G, AI and cloud computing, are pushing forward the fourth industrial revolution, pushing forward the digital transformation of university management, and remarkable achievements have been ma...New technologies, such as 5G, AI and cloud computing, are pushing forward the fourth industrial revolution, pushing forward the digital transformation of university management, and remarkable achievements have been made in university information construction. With the continuous development of big data, university network security has also become a major concern. Therefore, this paper first introduces the characteristics of university network from the perspective of big data, and then introduces the security risks of university network from the perspective of big data, which can provide the corresponding solutions to these problems.展开更多
Expressed Sequence Tag (EST) analysis has pioneered genome-wide gene discovery and expression profiling. In order to establish a gene expression index in the rice cultivar indica, we sequenced and analyzed 86,136 ESTs...Expressed Sequence Tag (EST) analysis has pioneered genome-wide gene discovery and expression profiling. In order to establish a gene expression index in the rice cultivar indica, we sequenced and analyzed 86,136 ESTs from nine rice cDNA libraries from the super hybrid cultivar LYP9 and its parental cultivars. We assembled these ESTs into 13,232 contigs and leave 8,976 singletons. Overall, 7,497 sequences were found similar to the existing sequences in GenBank and 14,711 are novel. These sequences are classified by molecular function, biological process and pathways according to the Gene Ontology. We compared our sequenced ESTs with the publicly available 95,000 ESTs from japonica, and found little sequence variation, despite the large difference between genome sequences. We then assembled the combined 173,000 rice ESTs for further analysis. Using the pooled ESTs, we compared gene expression in metabolism pathway between rice and Arabidopsis according to KEGG. We further profiled gene expression patterns in different tissues, developmental stages, and in a conditional sterile mutant, after checking the libraries are comparable by means of sequence coverage. We also identified some possible library specific genes and a number of enzymes and transcription factors that contribute to rice development.展开更多
With the further perfection achieved in China socialist market - oriented economic system and its pending accession to WTO, the silver market of this country has opened all- roundedly, and the modification for the gol...With the further perfection achieved in China socialist market - oriented economic system and its pending accession to WTO, the silver market of this country has opened all- roundedly, and the modification for the gold management system in force is well underway. This has aroused a profound interestamong powerful traders at home and abroad. What's more, they are eager to know more about the operational procedures of gold and silver under the current system newly regulated so that they can make appropriate readjustment of their internal operating management to it accordingly. To this end, the展开更多
文摘Aim: To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate (TU) treatment. Methods: Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 days for 130 days. The numbers of all types of cells (nuclei) in the seminiferous tubules and the interstitial tissue were estimated using a contemporary stereological tool, the optical disector. Results: In response to TU treatment, the numbers of non-type B spermatogonia, type B spermatogonia and late elongated spermatids per testis were reduced to 51 %, 66 % and 14 % of the controls, respectively. The conversion ratios from type B spermatogonia to early spermatocytes and pachytene spermatocytes were not significantly affected and the ratios to the later germ cell types fell to 51 % - 65 % of the controls. Less than 1.0 % of immature round spermatids were seen sloughing into the tubule lumen, 4.0 % of elongated spermatids retained in the seminiferous epithelium, and about half of the elongated spermatid nuclei appreciably malformed. Leydig cells were atrophied but their number and the peritubular myoid cell number per testis were unchanged. Conclusion: Double inhibition of spermatogenesis (i.e. inhibition at spermiation and spermatogonial conversion to type B spermatogonia), a scenario seen in the monkey and human following gona-dotrophin withdrawal, was not sufficiently effective for a complete spermatogenic suppression in the rat after TU treatment, probably due to ineffective inhibition of the Leydig cell population and therefore the intra-testicular testosterone levels.
基金supported by the National Natura1 Science Foundation of China(39470457) the Ninth Five-Year Major Program of China.
文摘In the cross between B. napus with OguCMSOrychophragmus violaceus, pre-fertilizatiocompatibility was observed. An intergeneric hybrid was successfully obtained by usinovary culture. The hybrid status was confirmed by cytology, morphology, fertilityisozyme and miosis analysis. The seed setting rate was 0.0072%. An amphidiploid of thhybrid was also produced by the use of chromosome-doubling method with 0.1% colchicinetreatment. Obtaining this hybrid and its amphidiploid has important theoretical anutilization value.
文摘The effects of graphite granularity on the properties of low carbon MgO-C based materials have been investigated in the work. Large crystal fused magnesia, natural flake graphite with different particle sizes and anti-oxidant were adopted as raw material for preparation of specimens. However, the results show that the physical properties, oxidation resistance and thermal shock resistance of low carbon MgO-C materials with content of 4.0wt% graphite are improved obviously through the use of special and suitable size graphite. The excellent performance achieved was considered as a result of microstructure modification of MgO-C materials. Therefore, it is suggested that both fine and micro grade natural flake graphite used for production of low carbon MgO-C bricks.
文摘The flowering phenology, pollination ecology and breeding system of Caesa/pinia crista L.were studied in Dinghushan Nature Reserve, Guangdong, China. The species started blooming in Februaryor March, then last till late April. It took about one week from first flower appearance to its full blooming,which lasted for 2-4 d. The pollen-ovule ratio was 18 000~500. The breeding system was self-incompatible,and protogynous xenogamy. Hymenoptera constituted the major group of pollinators. The pollination typeis ambophily, the species could be pollinated by wind if the pollinators were unavailable: this is the firstrecord of ambophily in the genus Caesalpinia. The floral structure adaptation to the pollinating behavior ofcarpenter bees was described. The influences of artificial treatments in pollination biological studies onthe flowering and fruiting of the plants were also discussed.
基金supported by the key project of Science and Technology Commission of Shanghai Local Government(015211010)
文摘Computer aided design of heat treatment for AISI P20 mold steel with good machinability is attempted to proceed by the commercial software package Thermo-Calc (TCP+DICTRA). Through experimental and theoretical analysis of phase transformation during heat treatment, further knowledge of designing proper heat treatment is obtained. Then the machinability of AISI P20+Ni steel under given heat treatment condition is studied and the influencing factors to their machinability are analyzed. It is shown that heat treatment designed by computer simulation of carbide transformation is applicable to AISI P20+Ni steel with good machinability; AISI P20+Ni steel with tempered sorbite treated by quenching & tempering has optimal machinability; normalizing at the temperature of 910°C & tempering can avoid cracking and result in acceptable machinability in small thickness module.
文摘Thermo-Calc software package (TCP+DICTRA) was used to simulate the carbide transformation process in die steel for plastic. Combined with TEM analysis, the calculated result confirms that the carbide in equilibrium state is M_7C_3 carbide. The dissolution of M_7C_3 carbide in steel is predicted by DICTRA program. It was shown that the temperature remarkably affects the dissolution process of M_7C_3 carbide, but the influence of alloy elements such as manganese and molybdenum can be neglected in this steel.
文摘Education informatization plays an increasingly prominent supporting and leading role in education reform and development. Currently, accelerating education informatization still faces many difficulties and problems. Compared with the requirements of the CPC Central Committee and the State Council, and compared with the level of deep application and integration innovation in developed countries, there are still gaps and many problems. At present, cloud computing, big data, Internet of Things, mobile computing and other new technologies are gradually widely used, the pace of informatization in all sectors of the economy and society is accelerating, the overall level of informatization in society is deepening, and the revolutionary impact of information technology on education is becoming increasingly obvious. Under the general trend of such technology, the cloud platform of comprehensive business based on cloud computing technology will be planned and built in an overall way to provide strong support for medical teaching, scientific research, innovation and development of faculty and students of the university. The integrated business platform provides cloud services such as standard IT infrastructure, student training platform, medical teaching and research, scientific research and development, and "entrepreneurship and innovation". Students and teachers can access and use IT at any time through the network. The content of each service can be customized and expanded according to the requirements of teachers and students. With the promotion of the service, the audience can be extended from teachers and students to users outside the school.
文摘sST2 is one of the members of interleukin-1 receptor family. When the myocardium is excessively pulled, sST2 and ST2L competitively bind IL-33, reducing the IL-33/ST2L signal pathway, which leads to accelerated myocardial remodeling and ventricular dysfunction. Unlike natriuretic peptide, sST2 is almost unaffected by age, gender, race, BMI, etiology of heart failure, atrial fibrillation, anemia, kidney function and other factors. At present, sST2 has played an important role in the diagnosis, prognosis and risk stratification of heart failure. With the deepening of clinical research, the application value of sST2 in other cardiovascular diseases needs further discussion. In addition, patients with metabolic syndrome and other diseases that affect myocardial metabolism and myocardial remodeling can consider to further assess the severity of the disease by measuring the concentration of sST2 and dynamically monitoring it.
文摘New technologies, such as 5G, AI and cloud computing, are pushing forward the fourth industrial revolution, pushing forward the digital transformation of university management, and remarkable achievements have been made in university information construction. With the continuous development of big data, university network security has also become a major concern. Therefore, this paper first introduces the characteristics of university network from the perspective of big data, and then introduces the security risks of university network from the perspective of big data, which can provide the corresponding solutions to these problems.
基金supported in part by the Department of Physics,Peking Universityin part by the Center for Research and Development of Superconductivity in China under contract No.BKBRSF-G19990646-02
文摘Expressed Sequence Tag (EST) analysis has pioneered genome-wide gene discovery and expression profiling. In order to establish a gene expression index in the rice cultivar indica, we sequenced and analyzed 86,136 ESTs from nine rice cDNA libraries from the super hybrid cultivar LYP9 and its parental cultivars. We assembled these ESTs into 13,232 contigs and leave 8,976 singletons. Overall, 7,497 sequences were found similar to the existing sequences in GenBank and 14,711 are novel. These sequences are classified by molecular function, biological process and pathways according to the Gene Ontology. We compared our sequenced ESTs with the publicly available 95,000 ESTs from japonica, and found little sequence variation, despite the large difference between genome sequences. We then assembled the combined 173,000 rice ESTs for further analysis. Using the pooled ESTs, we compared gene expression in metabolism pathway between rice and Arabidopsis according to KEGG. We further profiled gene expression patterns in different tissues, developmental stages, and in a conditional sterile mutant, after checking the libraries are comparable by means of sequence coverage. We also identified some possible library specific genes and a number of enzymes and transcription factors that contribute to rice development.
文摘With the further perfection achieved in China socialist market - oriented economic system and its pending accession to WTO, the silver market of this country has opened all- roundedly, and the modification for the gold management system in force is well underway. This has aroused a profound interestamong powerful traders at home and abroad. What's more, they are eager to know more about the operational procedures of gold and silver under the current system newly regulated so that they can make appropriate readjustment of their internal operating management to it accordingly. To this end, the
