In the past two years,significant progresses have been achieved in high-performance cast and wrought magnesium and magnesium alloys,magnesium-based composites,advanced cast technologies,advanced processing technologie...In the past two years,significant progresses have been achieved in high-performance cast and wrought magnesium and magnesium alloys,magnesium-based composites,advanced cast technologies,advanced processing technologies,and functional magnesium materials,such as Mg ion batteries,hydrogen storage Mg materials,bio-magnesium alloys,etc.Great contributions to the development of new magnesium alloys and their processing technologies have been made by Chongqing University,Shanghai Jiaotong University,Chinese Academy of Sciences,Helmholtz Zentrum Geesthacht,Queensland University,Brunel University,etc.This review paper is aimed to summarize the latest important advances in cast magnesium alloys,wrought magnesium alloys and functional magnesium materials worldwide in 2018–2019,including both the development of new materials and the innovation of their processing technologies.Based on the issues and challenges identified here,some future research directions are suggested,including further development of high-performance magnesium alloys having high strength and superior plasticity together with high corrosion resistance and low cost,and fundamental research on the phase diagram,diffusion,precipitation,etc.,as well as the development of advanced welding and joining technology.展开更多
AIM: To identify the property of dendritic cells (DCs) of peripheral blood monocytes (PBMC) in patients with chronic HBV infection. METHODS: Twenty patients with persistent HBV infection were included in this study, 1...AIM: To identify the property of dendritic cells (DCs) of peripheral blood monocytes (PBMC) in patients with chronic HBV infection. METHODS: Twenty patients with persistent HBV infection were included in this study, 10 healthy subjects being used as a control group. The peripheral blood mononuclear cells (PBMC) of T cell-depleted populations were incubated and induced into mature dendritic cells in the RPMI-1640 medium in the presence of cytokines GM-CSF, IL-4, FLt-3,TNF-alpha and 100mL.L(-1 )of fetal calf serum for a total of 10-12 days. The expressions of surface markers on DCs were evaluated using flow cytometric analysis. ELISA method was used to determine the cytokine levels of interleukin-12 (IL-12) and IL-10 in the supernatant produced by DCs. For detection of the stimulatory capacity of DCs to T cell proliferation, mytomycin C-treated DC were incubated with allogenic T cells. RESULTS: A typical morphology of mature DCs from healthy subjects and HBV-infected patients was induced in in vitro incubation, but the proliferation ability and cellular number of DCs from HBV-infected patients significantly decreased compared with healthy individuals. In particular, the expression levels of HLA-DR, CD80 (B7-1) and CD86 (B7-2) on DC surface from patients were also lower than that from healthy individuals (0.46 vs 0.92 for HLA-DR, 0.44 vs 0.88 for CD80 and 0.44 vs 0.84 for CD86,P【0.05). The stimulatory capacity and production of IL-12 of DCs from patients in allogenic mixed lymphocyte reaction (AMLR) significantly decreased, but the production level of nitric oxide (NO) by DCs simultaneously increased compared with healthy subjects (86 +/- 15 vs 170 +/- 22 micromol.L(-1), P 【0.05). CONCLUSION: The patients with chronic HBV infection have the defective function and immature phenotype of dendritic cells, which may be associated with the inability of efficient presentation of HBV antigens to host immune system for the clearance of HBV.展开更多
AIM: To establish clone cells with different metastatic potential for the study of metastasis-related mechanisms. METHODS: Cloning procedure was performed on parental hepatocellular carcinoma (HCC) cell line MHCC97, a...AIM: To establish clone cells with different metastatic potential for the study of metastasis-related mechanisms. METHODS: Cloning procedure was performed on parental hepatocellular carcinoma (HCC) cell line MHCC97, and biological characteristics of the target clones selected by in vivo screening were studied. RESULTS: Two clones with high (MHCC97-H) and low (MHCC97-L) metastatic potential were isolated from the parent cell line. Compared with MHCC97-L, MHCC97-H had smaller cell size (average cell diameter 43 microm vs 50 microm) and faster in vitro and in vivo growth rate (tumor cell doubling time was 34.2h vs 60.0h). The main ranges of chromosomes were 55-58 in MHCC97-H and 57-62 in MHCC97-L. Boyden chamber in vitro invasion assay demonstrated that the number of penetrating cells through the artificial basement membrane was (37.5 +/- 11.0) cells/field for MHCC97-H vs (17.7 +/- 6.3)/field for MHCC97-L. The proportions of cells in G0-G1 phase, S phase, and G2-M phase for MHCC97-H/MHCC97-L were 0.56/0.65, 0.28/0.25 and 0.16/0.10, respectively, as measured by flow cytometry. The serum AFP levels in nude mice 5wk after orthotopic implantation of tumor tissue were (246 +/- 66) microg.L(-1) for MHCC97-H and (91 +/- 66) microg.L(-1) for MHCC97-L. The pulmonary metastatic rate was 100% (10/10) vs 40% (4/10). CONCLUSION: Two clones of the same genetic background but with different biological behaviors were established, which could be valuable models for investigation on HCC metastasis.展开更多
Arid and semi-arid areas comprise about 30% of the earth＇s surface. Changes in climate and climate variability will likely have a significant impact on these regions. The Loess Plateau over Northwest China is a speci...Arid and semi-arid areas comprise about 30% of the earth＇s surface. Changes in climate and climate variability will likely have a significant impact on these regions. The Loess Plateau over Northwest China is a special semi-arid land surface and part of a dust aerosol source. To improve understanding and capture the direct evidence of the impact of human activity on the semi-arid climate over the Loess Plateau, the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） was established in 2005. SACOL consists of a large set of instruments and focuses on： （1） monitoring of long term tendencies in semiarid climate changes; （2） monitoring of the aerosol effect on the water cycle; （3） studies of interaction between land surface and the atmosphere; （4） improving the land surface and climate models; and （5） validation of space-borne observations. This paper presents a description of SACOL objectives, measurements, and sampling strategies. Preliminary observation results are also reviewed in this paper.展开更多
Adopting the Easterling-Peterson (EP) techniques and considering the reality of Chinese meteorological observations, this paper designed several tests and tested for inhomogeneities in all Chinese historical surface a...Adopting the Easterling-Peterson (EP) techniques and considering the reality of Chinese meteorological observations, this paper designed several tests and tested for inhomogeneities in all Chinese historical surface air temperature series from 1951 to 2001. The result shows that the time series have been widely impacted by inhomogeneities resulting from the relocation of stations and changes in local environment such as urbanization or some other factors. Among these factors, station relocations caused the largest magnitude of abrupt changes in the time series, and other factors also resulted in inhomogeneities to some extent. According to the amplitude of change of the difference series and the monthly distribution features of surface air temperatures, discontinuities identified by applying both the E-P technique and supported by China's station history records, or by comparison with other approaches, have been adjusted. Based on the above processing, the most significant temporal inhomogeneities were eliminated, and China's most homogeneous surface air temperature series has thus been created. Results show that the inhomogeneity testing captured well the most important change of the stations, and the adjusted dataset is more reliable than ever. This suggests that the adjusted temperature dataset has great value of decreasing the uncertaities in the study of observed climate change in China.展开更多
The navy and other Department of Defense organizations are increasingly interested in the use of unmanned surface vehicles (USVs) for a variety of missions and applications. The term USV refers to any vehicle that ope...The navy and other Department of Defense organizations are increasingly interested in the use of unmanned surface vehicles (USVs) for a variety of missions and applications. The term USV refers to any vehicle that operates on the surface of the water without a crew. USVs have the potential, and in some cases the demonstrated ability, to reduce risk to manned forces, provide the necessary force multiplication to accomplish military missions, perform tasks which manned vehicles cannot, and do so in a way that is affordable for the navy. A survey of USV activities worldwide as well as the general technical challenges of USVs was presented below. A general description of USVs was provided along with their typical applications. The technical challenges of developing a USV include its intelligence level, control, high stability, and developmental cost reduction. Through the joint efforts of researchers around the world, it is believed that the development of USVs will enter a new phase in the near future, as USVs could soon be applied widely both in military and civilian service.展开更多
The reach of tribology has expanded in diverse fields and tribology related research activities have seen immense growth during the last decade.This review takes stock of the recent advances in research pertaining to ...The reach of tribology has expanded in diverse fields and tribology related research activities have seen immense growth during the last decade.This review takes stock of the recent advances in research pertaining to different aspects of tribology within the last 2 to 3 years.Different aspects of tribology that have been reviewed including lubrication,wear and surface engineering,biotribology,high tem perature tribology,and computational tribology.This review attempts to highlight recent research and also presents future outlook pertaining to these aspects.It may however be noted that there are limitations of this review.One of the most important of these is that tribology being a highly multidisciplinary field,the research results are widely spread across various disciplines and there can be omissions because of this.Secondly,the topics dealt with in the field of tribology include only some of the salient topics(such as lubrication,wear,surface engineering,biotribology,high tem perature tribology,and computational tribology)but there are many more aspects of tribology that have not been covered in this review.Despite these limitations it is hoped that such a review will bring the most recent salient research in focus and will be beneficial for the growing community of tribology researchers.展开更多
Soil moisture plays an important role in land-atmosphere interactions. It is an important geophysical parameter in research on climate, hydrology, agriculture, and forestry. Soil moisture has important climatic effect...Soil moisture plays an important role in land-atmosphere interactions. It is an important geophysical parameter in research on climate, hydrology, agriculture, and forestry. Soil moisture has important climatic effects by influencing ground evapotranspi ration, runoff, surface reflectivity, surface emissivity, surface sensible heat and latent heat flux. At the global scale, the extent of its influence on the atmosphere is second only to that of sea surface temperature. At the terrestrial scale, its influence is even greater than that of sea surface temperatures. This paper presents a China Land Soil Moisture Data Assimilation System (CLSMDAS) based on EnKF and land process models, and results of the application of this system in the China Land Soil Moisture Data Assimilation tests. CLSMDAS is comprised of the following components: 1) A land process mo del—Community Land Model Version 3.0 (CLM3.0)—developed by the US National Center for Atmospheric Research (NCAR); 2) Precipitation of atmospheric forcing data and surface-incident solar radiation data come from hourly outputs of the FY2 geostationary meteorological satellite; 3) EnKF (Ensemble Kalman Filter) land data assimilation method; and 4) Observa tion data including satellite-inverted soil moisture outputs of the AMSR-E satellite and soil moisture observation data. Results of soil moisture assimilation tests from June to September 2006 were analyzed with CLSMDAS. Both simulation and assimila tion results of the land model reflected reasonably the temporal-spatial distribution of soil moisture. The assimilated soil mois ture distribution matches very well with severe summer droughts in Chongqing and Sichuan Province in August 2006, the worst since the foundation of the People’s Republic of China in 1949. It also matches drought regions that occurred in eastern Hubei and southern Guangxi in September.展开更多
基金The content in this review is financially supported by the National Key Research and Development Program of China(No.2016YFB0301100,2017YFF0209100)the National Science Foundation for Scientists of China(No.51531002,51474043,51701027,51971042,51901028)the Chongqing Academician Special Fund(cstc2018jcyj-yszxX0007,cstc2019yszxjcyjX0004).
文摘In the past two years,significant progresses have been achieved in high-performance cast and wrought magnesium and magnesium alloys,magnesium-based composites,advanced cast technologies,advanced processing technologies,and functional magnesium materials,such as Mg ion batteries,hydrogen storage Mg materials,bio-magnesium alloys,etc.Great contributions to the development of new magnesium alloys and their processing technologies have been made by Chongqing University,Shanghai Jiaotong University,Chinese Academy of Sciences,Helmholtz Zentrum Geesthacht,Queensland University,Brunel University,etc.This review paper is aimed to summarize the latest important advances in cast magnesium alloys,wrought magnesium alloys and functional magnesium materials worldwide in 2018–2019,including both the development of new materials and the innovation of their processing technologies.Based on the issues and challenges identified here,some future research directions are suggested,including further development of high-performance magnesium alloys having high strength and superior plasticity together with high corrosion resistance and low cost,and fundamental research on the phase diagram,diffusion,precipitation,etc.,as well as the development of advanced welding and joining technology.
基金National Natural Science Foundation of China,No.39970831.
文摘AIM: To identify the property of dendritic cells (DCs) of peripheral blood monocytes (PBMC) in patients with chronic HBV infection. METHODS: Twenty patients with persistent HBV infection were included in this study, 10 healthy subjects being used as a control group. The peripheral blood mononuclear cells (PBMC) of T cell-depleted populations were incubated and induced into mature dendritic cells in the RPMI-1640 medium in the presence of cytokines GM-CSF, IL-4, FLt-3,TNF-alpha and 100mL.L(-1 )of fetal calf serum for a total of 10-12 days. The expressions of surface markers on DCs were evaluated using flow cytometric analysis. ELISA method was used to determine the cytokine levels of interleukin-12 (IL-12) and IL-10 in the supernatant produced by DCs. For detection of the stimulatory capacity of DCs to T cell proliferation, mytomycin C-treated DC were incubated with allogenic T cells. RESULTS: A typical morphology of mature DCs from healthy subjects and HBV-infected patients was induced in in vitro incubation, but the proliferation ability and cellular number of DCs from HBV-infected patients significantly decreased compared with healthy individuals. In particular, the expression levels of HLA-DR, CD80 (B7-1) and CD86 (B7-2) on DC surface from patients were also lower than that from healthy individuals (0.46 vs 0.92 for HLA-DR, 0.44 vs 0.88 for CD80 and 0.44 vs 0.84 for CD86,P【0.05). The stimulatory capacity and production of IL-12 of DCs from patients in allogenic mixed lymphocyte reaction (AMLR) significantly decreased, but the production level of nitric oxide (NO) by DCs simultaneously increased compared with healthy subjects (86 +/- 15 vs 170 +/- 22 micromol.L(-1), P 【0.05). CONCLUSION: The patients with chronic HBV infection have the defective function and immature phenotype of dendritic cells, which may be associated with the inability of efficient presentation of HBV antigens to host immune system for the clearance of HBV.
基金Supportod ty the State Key Basic Research Program Grant G1998051211 the Fund for Leading Specialty of Shanghai Metropolitan Bureau of Public Health.
文摘AIM: To establish clone cells with different metastatic potential for the study of metastasis-related mechanisms. METHODS: Cloning procedure was performed on parental hepatocellular carcinoma (HCC) cell line MHCC97, and biological characteristics of the target clones selected by in vivo screening were studied. RESULTS: Two clones with high (MHCC97-H) and low (MHCC97-L) metastatic potential were isolated from the parent cell line. Compared with MHCC97-L, MHCC97-H had smaller cell size (average cell diameter 43 microm vs 50 microm) and faster in vitro and in vivo growth rate (tumor cell doubling time was 34.2h vs 60.0h). The main ranges of chromosomes were 55-58 in MHCC97-H and 57-62 in MHCC97-L. Boyden chamber in vitro invasion assay demonstrated that the number of penetrating cells through the artificial basement membrane was (37.5 +/- 11.0) cells/field for MHCC97-H vs (17.7 +/- 6.3)/field for MHCC97-L. The proportions of cells in G0-G1 phase, S phase, and G2-M phase for MHCC97-H/MHCC97-L were 0.56/0.65, 0.28/0.25 and 0.16/0.10, respectively, as measured by flow cytometry. The serum AFP levels in nude mice 5wk after orthotopic implantation of tumor tissue were (246 +/- 66) microg.L(-1) for MHCC97-H and (91 +/- 66) microg.L(-1) for MHCC97-L. The pulmonary metastatic rate was 100% (10/10) vs 40% (4/10). CONCLUSION: Two clones of the same genetic background but with different biological behaviors were established, which could be valuable models for investigation on HCC metastasis.
基金SACOL was sponsored by Lanzhou University through 985 Programthe National Basic Research Program of China under Grant No. 2006CB400501the National Natural Science Founda- tion of China under Grant Nos. 40633017 and 40725015
文摘Arid and semi-arid areas comprise about 30% of the earth＇s surface. Changes in climate and climate variability will likely have a significant impact on these regions. The Loess Plateau over Northwest China is a special semi-arid land surface and part of a dust aerosol source. To improve understanding and capture the direct evidence of the impact of human activity on the semi-arid climate over the Loess Plateau, the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） was established in 2005. SACOL consists of a large set of instruments and focuses on： （1） monitoring of long term tendencies in semiarid climate changes; （2） monitoring of the aerosol effect on the water cycle; （3） studies of interaction between land surface and the atmosphere; （4） improving the land surface and climate models; and （5） validation of space-borne observations. This paper presents a description of SACOL objectives, measurements, and sampling strategies. Preliminary observation results are also reviewed in this paper.
文摘Adopting the Easterling-Peterson (EP) techniques and considering the reality of Chinese meteorological observations, this paper designed several tests and tested for inhomogeneities in all Chinese historical surface air temperature series from 1951 to 2001. The result shows that the time series have been widely impacted by inhomogeneities resulting from the relocation of stations and changes in local environment such as urbanization or some other factors. Among these factors, station relocations caused the largest magnitude of abrupt changes in the time series, and other factors also resulted in inhomogeneities to some extent. According to the amplitude of change of the difference series and the monthly distribution features of surface air temperatures, discontinuities identified by applying both the E-P technique and supported by China's station history records, or by comparison with other approaches, have been adjusted. Based on the above processing, the most significant temporal inhomogeneities were eliminated, and China's most homogeneous surface air temperature series has thus been created. Results show that the inhomogeneity testing captured well the most important change of the stations, and the adjusted dataset is more reliable than ever. This suggests that the adjusted temperature dataset has great value of decreasing the uncertaities in the study of observed climate change in China.
基金Research Fund from Science and Technology on Underwater Vehicle Laboratory
文摘The navy and other Department of Defense organizations are increasingly interested in the use of unmanned surface vehicles (USVs) for a variety of missions and applications. The term USV refers to any vehicle that operates on the surface of the water without a crew. USVs have the potential, and in some cases the demonstrated ability, to reduce risk to manned forces, provide the necessary force multiplication to accomplish military missions, perform tasks which manned vehicles cannot, and do so in a way that is affordable for the navy. A survey of USV activities worldwide as well as the general technical challenges of USVs was presented below. A general description of USVs was provided along with their typical applications. The technical challenges of developing a USV include its intelligence level, control, high stability, and developmental cost reduction. Through the joint efforts of researchers around the world, it is believed that the development of USVs will enter a new phase in the near future, as USVs could soon be applied widely both in military and civilian service.
基金National N atural Science Foundation of China(Grant Nos.51635009 and 51775460)the funding of State Key Laboratory of Tribology,China(SKLT2018C05).
文摘The reach of tribology has expanded in diverse fields and tribology related research activities have seen immense growth during the last decade.This review takes stock of the recent advances in research pertaining to different aspects of tribology within the last 2 to 3 years.Different aspects of tribology that have been reviewed including lubrication,wear and surface engineering,biotribology,high tem perature tribology,and computational tribology.This review attempts to highlight recent research and also presents future outlook pertaining to these aspects.It may however be noted that there are limitations of this review.One of the most important of these is that tribology being a highly multidisciplinary field,the research results are widely spread across various disciplines and there can be omissions because of this.Secondly,the topics dealt with in the field of tribology include only some of the salient topics(such as lubrication,wear,surface engineering,biotribology,high tem perature tribology,and computational tribology)but there are many more aspects of tribology that have not been covered in this review.Despite these limitations it is hoped that such a review will bring the most recent salient research in focus and will be beneficial for the growing community of tribology researchers.
基金supported by National High Technology Research and Development Program of China (Grant Nos. 2007AA12Z144, 2009AA12Z129)Chinese COPES Project (Grant Nos. GYHY200706005, GYHY200806014)China Meteorological Administration New Technology Promotion Project (Grant No. CMATG2008Z04)
文摘Soil moisture plays an important role in land-atmosphere interactions. It is an important geophysical parameter in research on climate, hydrology, agriculture, and forestry. Soil moisture has important climatic effects by influencing ground evapotranspi ration, runoff, surface reflectivity, surface emissivity, surface sensible heat and latent heat flux. At the global scale, the extent of its influence on the atmosphere is second only to that of sea surface temperature. At the terrestrial scale, its influence is even greater than that of sea surface temperatures. This paper presents a China Land Soil Moisture Data Assimilation System (CLSMDAS) based on EnKF and land process models, and results of the application of this system in the China Land Soil Moisture Data Assimilation tests. CLSMDAS is comprised of the following components: 1) A land process mo del—Community Land Model Version 3.0 (CLM3.0)—developed by the US National Center for Atmospheric Research (NCAR); 2) Precipitation of atmospheric forcing data and surface-incident solar radiation data come from hourly outputs of the FY2 geostationary meteorological satellite; 3) EnKF (Ensemble Kalman Filter) land data assimilation method; and 4) Observa tion data including satellite-inverted soil moisture outputs of the AMSR-E satellite and soil moisture observation data. Results of soil moisture assimilation tests from June to September 2006 were analyzed with CLSMDAS. Both simulation and assimila tion results of the land model reflected reasonably the temporal-spatial distribution of soil moisture. The assimilated soil mois ture distribution matches very well with severe summer droughts in Chongqing and Sichuan Province in August 2006, the worst since the foundation of the People’s Republic of China in 1949. It also matches drought regions that occurred in eastern Hubei and southern Guangxi in September.
