[Objective] The aim was to compare the morphology difference between male and female individuals of Paramisgurnus dabryanus Sauvage. [Method] The comparison of 10 morphological characteristics between male and female ...[Objective] The aim was to compare the morphology difference between male and female individuals of Paramisgurnus dabryanus Sauvage. [Method] The comparison of 10 morphological characteristics between male and female individuals of P. dabryanus was conducted with principal component analysis and t-test methods. [Result] The results of t-test indicated that three of 10 morphological characteristics showed extremely significant difference（P0.01）and one of 10 morphological characteristics was significantly different（P0.05）. Principal component analysis revealed four principal components,the contribution rate of which was 31.151%,18.844%,12.324% and 10.169%,respectively. The cumulative contribution rate had reached 72.487%. The morphological variations between male and female individuals were not significant,which was consistent with that of t-test. [Conclusion] The result in this study had provided theoretical basis for the breeding of P. dabryanus.展开更多
In order to achieve automatic adjustment of the double-nut ball screw preload, a magnetostrictive ball screw preload system is proposed. A new cylindrical giant magnetostrictive actuator （CGMA）, which is the core co...In order to achieve automatic adjustment of the double-nut ball screw preload, a magnetostrictive ball screw preload system is proposed. A new cylindrical giant magnetostrictive actuator （CGMA）, which is the core component of the preload system, is developed using giant magnetostrictive material （GMM） with a hole. The pretightening force of the CGMA is determined by testing. And the magnetic circuit analysis method is introduced to calculate magnetic field intensity of the actuator with a ball screw shaft. To suppress the thermal effects on the magnetostrictive outputs, an oil cooling method which can directly cool the heat source is adopted. A CGMA test platform is established and the static and dynamic output characteristics are respectively studied. The experimental results indicate that the CGMA has good linearity and no double-frequency effect under the bias magnetic field and the output accuracy of the CGMA is significantly improved with cooling measures. Although the output decreased with screw shaft through the actuator, the performance of CGMA meets the design requirements for ball screw preload with output displacement more than 26 μm and force up to 6200 N. The development of a CGMA will provide a new approach for automatic adjustment of double-nut ball screw preload.展开更多
Objective.To investigate the distribution frequency of parathyroid hormone(PTH)gene polymorphism in healthy adults from Bejing area and to explore the association of PTH genotypes with bone mineral density(BMD).Method...Objective.To investigate the distribution frequency of parathyroid hormone(PTH)gene polymorphism in healthy adults from Bejing area and to explore the association of PTH genotypes with bone mineral density(BMD).Methods.PTH gene polymorphism was detected in270subjects by polymerase chain reaction(PCR)and PCR /restriction fragment length polymorphism(PCR /RFLP).The digestion products of restriction enzyme Bst B1were separated on1%agarose gels.PTH genotypes were confirmed by DNA sequences analysis.BMD was measured by dual-energy X-ray absorptiometry(DEXA,DPX -L ,Lunar).Results.Genotype frequencies of BB,Bb,bb were73.7%,25.9%and0.4%respectively in Beijing adults(P<0.01),67.1%,32.2%and0.7%in postmenopausal women,which was different from Japanese wom-en.We statistically compared bone mineral density at the lumbar2-4and proximal femur between BB and Bb genotypes.No obvious association was found between the BMD and PTH genotypes in Beijing women(P>0.05).Conclusion.PTH gene polymorphism is not associated with BMD in Chinese women.The further research to explore the genetic risk factors of osteoporosis should be committed.展开更多
5-Fluorouracil （5-FU） is the most frequently used chemotherapy agent concomitant with radiotherapy in the management of patients with rectal cancer. Capecitabine is an oral fluoropyrimidine that mimics the pharmacon...5-Fluorouracil （5-FU） is the most frequently used chemotherapy agent concomitant with radiotherapy in the management of patients with rectal cancer. Capecitabine is an oral fluoropyrimidine that mimics the pharmaconkinetics of infusional 5-FU. This new drug is replacing 5-FU as a part of the combined-modality treatment of a number of gastrointestinal cancers. While cardiac events associated with the use of 5-FU are a well known side effect, capecitabine-induced cardiotoxicity has been only rarely reported. Here, we reviewed the case of a patient with rectal cancer who had a capecitabine-induced coronary vasospasm. The most prominent mutation of the dihydropyrimidine dehydrogenase gene was also analyzed.展开更多
The question of whether or not global warming has paused since more than ten years ago, namely ＂warming hia- tus＂, has attracted the attention of climate science community including the IPCC. Some authors have attri...The question of whether or not global warming has paused since more than ten years ago, namely ＂warming hia- tus＂, has attracted the attention of climate science community including the IPCC. Some authors have attributed the ＂warming hiatus＂ to the internal changes in the climate system, i.e., the recombination of ocean-atmosphere circulations. Therefore, it is necessary to propose higher requirements on reconstructing circulation background of climate change for the past millennium. However, the analyses of changes in atmospheric circulation over the last millennium as well as the conclusions of related re- gional climate patterns are so widely different and contradictory, bringing uncertainties to our understanding of regional even global climate change to a great extent. On the other hand, in the last 10 years the high-precision U/Th-dated stalagmite oxygen isotope ratio （δ^18O） sequences provided an accurate chronological frame for the paleoclimate study of the middle and late Pleistocene, in which all authors from China took the Chinese stalagmite δ^18O as the summer monsoon index without excep- tion. However, this point of view misleads the climate scientists into thinking that the stalagmite δ^18O can be as the proxy of precipitation amount. Nevertheless, it is well known that all of these records have a lot in common in the low frequency trend. However, most sequences cannot be calibrated by instrumental precipitation records, and thus the uncertainty of the climate research framework of China and even of the world has increased. Therefore, it is imperative for climatology to clarify the origin of contradiction and to reduce the uncertainty as early as possible. On the basis of analyzing the significance of stalag- mite ~180 in the monsoon regions of China, the author tries to propose a new circulation proxy in this paper： integrating the Chinese stalagmite oxygen isotope sequence to reconstruct the tropical Pacific sea surface temperature gradient, i.e., the large-scale ENSO-like state over the past millennium. Furthermore, the author speculates that it was warm in the modern times and the Medieval Period, but the circulation recombination was different in both periods. And this inference could be support- ed by the longer record since Last Glacial Maximum. In other words, the attribution analysis of the identical low-frequency trends of Chinese stalagmite t^180 on a large scale shows that the ENSO-like state controls the climate change in the monsoon regions of China at different time scales （from interannual to century or even longer time scales）. Wherein the important connection of circulations is the western Pacific subtropical high （WPSH）, that is to say, besides the interannual and decadal time scales, the WPSH would possess the circulation mode on longer timescales. For example, we may discuss the change of the WPSH in the whole Holocene epoch, i.e., the half precession period. These discussions could make sense to the study of not only the paleoclimate but also the modern climate.展开更多
基金Supported by Scientific and Technological Projects in Shandong Province~~
文摘[Objective] The aim was to compare the morphology difference between male and female individuals of Paramisgurnus dabryanus Sauvage. [Method] The comparison of 10 morphological characteristics between male and female individuals of P. dabryanus was conducted with principal component analysis and t-test methods. [Result] The results of t-test indicated that three of 10 morphological characteristics showed extremely significant difference（P0.01）and one of 10 morphological characteristics was significantly different（P0.05）. Principal component analysis revealed four principal components,the contribution rate of which was 31.151%,18.844%,12.324% and 10.169%,respectively. The cumulative contribution rate had reached 72.487%. The morphological variations between male and female individuals were not significant,which was consistent with that of t-test. [Conclusion] The result in this study had provided theoretical basis for the breeding of P. dabryanus.
基金Project(51475267) supported by the National Natural Science Foundation of China
文摘In order to achieve automatic adjustment of the double-nut ball screw preload, a magnetostrictive ball screw preload system is proposed. A new cylindrical giant magnetostrictive actuator （CGMA）, which is the core component of the preload system, is developed using giant magnetostrictive material （GMM） with a hole. The pretightening force of the CGMA is determined by testing. And the magnetic circuit analysis method is introduced to calculate magnetic field intensity of the actuator with a ball screw shaft. To suppress the thermal effects on the magnetostrictive outputs, an oil cooling method which can directly cool the heat source is adopted. A CGMA test platform is established and the static and dynamic output characteristics are respectively studied. The experimental results indicate that the CGMA has good linearity and no double-frequency effect under the bias magnetic field and the output accuracy of the CGMA is significantly improved with cooling measures. Although the output decreased with screw shaft through the actuator, the performance of CGMA meets the design requirements for ball screw preload with output displacement more than 26 μm and force up to 6200 N. The development of a CGMA will provide a new approach for automatic adjustment of double-nut ball screw preload.
文摘Objective.To investigate the distribution frequency of parathyroid hormone(PTH)gene polymorphism in healthy adults from Bejing area and to explore the association of PTH genotypes with bone mineral density(BMD).Methods.PTH gene polymorphism was detected in270subjects by polymerase chain reaction(PCR)and PCR /restriction fragment length polymorphism(PCR /RFLP).The digestion products of restriction enzyme Bst B1were separated on1%agarose gels.PTH genotypes were confirmed by DNA sequences analysis.BMD was measured by dual-energy X-ray absorptiometry(DEXA,DPX -L ,Lunar).Results.Genotype frequencies of BB,Bb,bb were73.7%,25.9%and0.4%respectively in Beijing adults(P<0.01),67.1%,32.2%and0.7%in postmenopausal women,which was different from Japanese wom-en.We statistically compared bone mineral density at the lumbar2-4and proximal femur between BB and Bb genotypes.No obvious association was found between the BMD and PTH genotypes in Beijing women(P>0.05).Conclusion.PTH gene polymorphism is not associated with BMD in Chinese women.The further research to explore the genetic risk factors of osteoporosis should be committed.
文摘5-Fluorouracil （5-FU） is the most frequently used chemotherapy agent concomitant with radiotherapy in the management of patients with rectal cancer. Capecitabine is an oral fluoropyrimidine that mimics the pharmaconkinetics of infusional 5-FU. This new drug is replacing 5-FU as a part of the combined-modality treatment of a number of gastrointestinal cancers. While cardiac events associated with the use of 5-FU are a well known side effect, capecitabine-induced cardiotoxicity has been only rarely reported. Here, we reviewed the case of a patient with rectal cancer who had a capecitabine-induced coronary vasospasm. The most prominent mutation of the dihydropyrimidine dehydrogenase gene was also analyzed.
基金supported by the Chinese Academy of Sciences Strategic Priority Research Program (Grant No. XDA05080501)the National Basic Research Program of China (Grant No. 2010CB950101)+1 种基金the National Natural Science Foundation of China (Grant No. 41030103)Basic Research Project of the Ministry of Science and Technology (Grant No. 2011FY120300)
文摘The question of whether or not global warming has paused since more than ten years ago, namely ＂warming hia- tus＂, has attracted the attention of climate science community including the IPCC. Some authors have attributed the ＂warming hiatus＂ to the internal changes in the climate system, i.e., the recombination of ocean-atmosphere circulations. Therefore, it is necessary to propose higher requirements on reconstructing circulation background of climate change for the past millennium. However, the analyses of changes in atmospheric circulation over the last millennium as well as the conclusions of related re- gional climate patterns are so widely different and contradictory, bringing uncertainties to our understanding of regional even global climate change to a great extent. On the other hand, in the last 10 years the high-precision U/Th-dated stalagmite oxygen isotope ratio （δ^18O） sequences provided an accurate chronological frame for the paleoclimate study of the middle and late Pleistocene, in which all authors from China took the Chinese stalagmite δ^18O as the summer monsoon index without excep- tion. However, this point of view misleads the climate scientists into thinking that the stalagmite δ^18O can be as the proxy of precipitation amount. Nevertheless, it is well known that all of these records have a lot in common in the low frequency trend. However, most sequences cannot be calibrated by instrumental precipitation records, and thus the uncertainty of the climate research framework of China and even of the world has increased. Therefore, it is imperative for climatology to clarify the origin of contradiction and to reduce the uncertainty as early as possible. On the basis of analyzing the significance of stalag- mite ~180 in the monsoon regions of China, the author tries to propose a new circulation proxy in this paper： integrating the Chinese stalagmite oxygen isotope sequence to reconstruct the tropical Pacific sea surface temperature gradient, i.e., the large-scale ENSO-like state over the past millennium. Furthermore, the author speculates that it was warm in the modern times and the Medieval Period, but the circulation recombination was different in both periods. And this inference could be support- ed by the longer record since Last Glacial Maximum. In other words, the attribution analysis of the identical low-frequency trends of Chinese stalagmite t^180 on a large scale shows that the ENSO-like state controls the climate change in the monsoon regions of China at different time scales （from interannual to century or even longer time scales）. Wherein the important connection of circulations is the western Pacific subtropical high （WPSH）, that is to say, besides the interannual and decadal time scales, the WPSH would possess the circulation mode on longer timescales. For example, we may discuss the change of the WPSH in the whole Holocene epoch, i.e., the half precession period. These discussions could make sense to the study of not only the paleoclimate but also the modern climate.
