In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to exam...In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to examine associations between h/day sitting,meeting (or not meeting) the U.S.Physical Activity Guidelines of≥150 min/week of moderate-and vigorous-intensity LTPA,and combinations of sitting time and LTPA on totaland trunk percent body fat (BF%).展开更多
This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to en...This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to enhance healthcare outcomes and reduce disparities,there is a growing concern that these technologies may inadvertently/advertently exacerbate existing racial inequalities.Focusing specifically on the experiences of Black patients,this research investigates how the following AI components:medical algorithms,machine learning,and natural learning processes are contributing to the unequal distribution of medical resources,diagnosis,and health care treatment of those classified as Black.Furthermore,this review employs a multidisciplinary approach,combining insights from computer science,medical ethics,and social justice theory to analyze the mechanisms through which AI systems may encode and reinforce racial biases.By dissecting the three primary components of AI,this paper aims to present a clear understanding of how these technologies work,how they intersect,and how they may inherently perpetuate harmful stereotypes resulting in negligent outcomes for Black patients.Furthermore,this paper explores the ethical implications of deploying AI in healthcare settings and calls for increased transparency,accountability,and diversity in the development and implementation of these technologies.Finally,it is important that I prefer the following paper with a clear and concise definition of what I refer to as Anti-Black racism throughout the text.Therefore,I assert the following:Anti-Black racism refers to prejudice,discrimination,or antagonism directed against individuals or communities of African descent based on their race.It involves the belief in the inherent superiority of one race over another and the systemic and institutional practices that perpetuate inequality and disadvantage for Black people.Furthermore,I proclaim that this form of racism can be manifested in various ways,such as unequal access to opportunities,resources,education,employment,and fair treatment within social,economic,and political systems.It is also pertinent to acknowledge that Anti-Black racism is deeply rooted in historical and societal structures throughout the U.S.borders and beyond,leading to systemic disadvantages and disparities that impact the well-being and life chances of Black individuals and communities.Addressing Anti-Black racism involves recognizing and challenging both individual attitudes and systemic structures that contribute to discrimination and inequality.Efforts to combat Anti-Black racism include promoting awareness,education,advocacy for policy changes,and fostering a culture of inclusivity and equality.展开更多
The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the pro...The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the process of adjustment to student life in Taiwan.Under investigation were cultural adjustment and coping skills as these students transitioned from West to East.Qualitative data were collected from interviews with participants and faculty members as well as participant observations.Results indicated that U.S.students found their own ways to acclimate to their new academic setting as well as to social relations,cross-cultural issues,and the linguistic environment in Taiwan to achieve effective adaptation.They made changes in themselves to cope with all situations they encountered.This study provides suggestions for international students abroad in Taiwan,for the Taiwan Residents government,and for universities or colleges in terms of what they should offer to current and future international students.展开更多
The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along ...The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along with their colleagues in the House of Representatives and require the popular social media app TikTok to be sold to an American company.If they do endorse the House vote,then ByteDance must divest itself of TikTok or see the app will be banned on U.S.-based social media platforms.展开更多
On January 5,the Chinese People's Association for Friendship with Foreign Countries and the Chinese People's Institute of Foreign Affairs jointly hosted a reception commemorating the 45th anniversary of the es...On January 5,the Chinese People's Association for Friendship with Foreign Countries and the Chinese People's Institute of Foreign Affairs jointly hosted a reception commemorating the 45th anniversary of the establishment of diplomatic relationship between China and the United States in Beijing.Member of the Political Bureau of the CPC Central Committee and Foreign Minister Wang Yi attended the commemoration and delivered aspeech.David Meale,ChargédAffaires at the U.S.Embassy in China,addressed the reception.He extended on behalf of the U.S.side congratulations on the anniversary,expressing the readiness of the U.S.to implement the consensus reached by the two heads of state and promote the steady development of U.S.-China relations.More than 350 people from all walks of life of both countries attended the reception.展开更多
The United States passed the Better Utilization of Investment Leading to Development(BUILD Act),as a counterweight to China’s overseas development activities.Under the Act,the US established a new federal agency,the ...The United States passed the Better Utilization of Investment Leading to Development(BUILD Act),as a counterweight to China’s overseas development activities.Under the Act,the US established a new federal agency,the U.S.International Development Finance Corporation(DFC),to enhance U.S.development financing capabilities.To better understand the impact of the DFC on China’s development finance,this article analyzes the DFC’s purpose,functions,structure,and funding.Then it focuses on the purpose of establishing the DFC,providing a preliminary analysis of the potential motivation for its establishment.It also compares the China Development Bank(CDB)and the DFC based on their focused sectors.Finally,through an in-depth analysis of financial frictions in China-U.S.relations,this article argues that the DFC competes with China’s overseas development financing activities in the context of broader strategic competition between China and the U.S.展开更多
Since the 1960s,the global natural gas industry has developed rapidly,and natural gas has become a fossil fuel that can balance supply stability,economic efficiency of consumption,clean and low-carbon features at the ...Since the 1960s,the global natural gas industry has developed rapidly,and natural gas has become a fossil fuel that can balance supply stability,economic efficiency of consumption,clean and low-carbon features at the current stage.However,there is a regional imbalance in the global demand for natural gas,and the continuous rise in geopolitical risks negatively affects the stability of the natural gas market.In recent years,LNG export capacity in the U.S.has continued to grow,and the potential for China-U.S.LNG trade in the future is enormous.From the perspective of development opportunities,strengthening LNG trade cooperation with the U.S.is conducive to the diversification of natural gas import sources for China.From the perspective of challenges,China-U.S.LNG trade cooperation also involves potential risks in terms of economy and channels.展开更多
The global supply chain is based on the global distribution of materials,technology,capital,labor,and markets and thus cannot be altered by political motives.KEEPING a sound and stable global supply chain will benefit...The global supply chain is based on the global distribution of materials,technology,capital,labor,and markets and thus cannot be altered by political motives.KEEPING a sound and stable global supply chain will benefit not only China and America,but also the world at large.Janet Yellen,U.S.secretary of treasury,has realized the devastating consequences of decoupling U.S.economy from Chinese economy when she spoke at John Hopkins Institute on April 20,2023.Yellen said,“The United States will assert ourselves when our vital interests are at stake.But we do not seek to decouple our economy from China’s.A full separation of our economies would be disastrous for both countries.It would be destabilizing for the rest of the world.”展开更多
At 1:35 p.m.local time on November 15,a four-hour summit between Chinese President Xi Jinping and U.S.President Joe Biden concluded at Filoli Estate in San Francisco.At a press briefing after the meeting,Wang Yi,membe...At 1:35 p.m.local time on November 15,a four-hour summit between Chinese President Xi Jinping and U.S.President Joe Biden concluded at Filoli Estate in San Francisco.At a press briefing after the meeting,Wang Yi,member of the Political Bureau of the CPC Central Committee and Minister of Foreign Affairs,said that“the two presidents had a very good,comprehensive,and in-depth meeting.”展开更多
Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has nat...Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has naturally endowed this region with different varieties of marble deposits. These marble deposits need proper characterization to ensure their proper use in the construction industry. This research aims to conduct a preliminary study for the characterization of the Nasir Abad Hunza marble deposit. Samples from said deposit were subjected to different tests to study its chemical, physical and mechanical properties. Results of XRF analysis reveal that the deposit under study is dolomitic. The comparison of different physical properties of deposits with standard values confirms its originality. However, high variation in the strength of core samples was observed, which could result from incomplete crystallization by metamorphism. This variation in the strength of samples suggests strength-based definitions of deposit domains to propose the use of each domain separately.展开更多
语言作为人类精神的产物和文明的载体应具有审美价值,而演讲作为一种特殊的语言表现形式,它的审美价值在于能够使受众在愉悦中自觉地去接受或容纳演讲的主旨。Speech on Hitler’s Invasion of the U.S.S.R.是丘吉尔政治生涯中重要的演...语言作为人类精神的产物和文明的载体应具有审美价值,而演讲作为一种特殊的语言表现形式,它的审美价值在于能够使受众在愉悦中自觉地去接受或容纳演讲的主旨。Speech on Hitler’s Invasion of the U.S.S.R.是丘吉尔政治生涯中重要的演讲作品之一,既具有时效性和实效性,又具有历久弥新的语言审美价值。展开更多
This paper analyzes the corn production cost in China, the U.S. and Brazil from 1997 to 2014. According to the results,(1) corn production cost in China is the highest among these three countries;(2) the rapid gro...This paper analyzes the corn production cost in China, the U.S. and Brazil from 1997 to 2014. According to the results,(1) corn production cost in China is the highest among these three countries;(2) the rapid growth of labor cost and land cost is the major factor that promotes the increase of total corn production cost in China;(3) the level of agricultural mechanization in China has been gradually improving, and the gap between agricultural mechanization levels in China and other two countries is constantly narrowing;(4) differing from the U.S. and Brazil,China exhibits a "high input, low output" agricultural production mode. Based on the above analyses, corresponding suggestions have been presented to reduce corn production cost in China.展开更多
AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human...AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.展开更多
Apoptosis is a form of genetically programmed cell death, which plays a key role in regulation of cellularity in a variety of tissue and cell types including the cardiovascular tissues. Under both physiological and pa...Apoptosis is a form of genetically programmed cell death, which plays a key role in regulation of cellularity in a variety of tissue and cell types including the cardiovascular tissues. Under both physiological and pathophysiological conditions, various biophysiological and biochemical factors, including mechanical forces, reactive oxygen and nitrogen species, cytokines, growth factors, oxidized lipoproteins, etc., may influence apoptosis of vascular cells. The Fas/Fas ligand/caspase death-signaling pathway, Bcl-2 protein family/mitochondria, the tumor suppressive gene p53, and the proto-oncogene c-myc may be activated in atherosclerotic lesions, and mediates vascular apoptosis during the development of atherosclerosis. Abnormal expression and dysfunction of these apoptosis-regulating genes may attenuate or accelerate vascular cell apoptosis and affect the integrity and stability of atherosclerotic plaques. Clarification of the molecular mechanism that regulates apoptosis may help design a new strategy for treatment of atherosclerosis and its major complication, the acute vascular syndromes.展开更多
Objective:China and the United States(the U.S.)have the heaviest colorectal cancer(CRC)burden with considerable variations in temporal trends.This study aims to analyze the temporal patterns of CRC burden and its risk...Objective:China and the United States(the U.S.)have the heaviest colorectal cancer(CRC)burden with considerable variations in temporal trends.This study aims to analyze the temporal patterns of CRC burden and its risk factors in China and the U.S.across the past three decades.Methods:Data were extracted from the Global Burden of Disease(GBD)Study in 2019,including cases,deaths,disability-adjusted life-years(DALYs),age-standardized rate(ASR),and summary exposure value(SEV)of CRC in China and the U.S.between 1990 and 2019.Annual average percentage changes(AAPCs)of CRC burden were calculated using the Joinpoint regression model.The mortality in CRC attributable to potential risk factors was characterized by countries,gender,and age groups.Results:In 2019,there were 607,900 and 227,241 CRC cases,and 261,777 and 84,026 CRC deaths in China and the U.S.,respectively.The age-standardized incidence rate(ASIR)was 30.55 per 100,000 in China and 41.86 per100,000 in the U.S.,and the age-standardized mortality rate(ASMR)was 13.86 per 100,000 in China and 14.77 per100,000 in the U.S.CRC incidence,mortality,and DALY rate in the U.S.showed downward trends in the past three decades(AAPC=-0.47,-1.06,and-0.88,respectively),while upward trends were observed in China(AAPC=3.11,1.05,and 0.91,respectively).Among the cause of CRC,the leading risk factor contributing to CRC death was low milk in China and smoking in the U.S.,respectively.Conclusions:From 1990 to 2019,the burden of CRC in China increased dramatically,particularly for males and middle-aged and elderly people.The management of the major risk factors associated with the high burden of CRC should be enhanced.展开更多
Proton exchange membrane fuel cells(PEMFC)have attracted much attention because of their high energy conversion efficiency,high power density and zero emission of pollutants.However,the high cost of the cathode platin...Proton exchange membrane fuel cells(PEMFC)have attracted much attention because of their high energy conversion efficiency,high power density and zero emission of pollutants.However,the high cost of the cathode platinum group metal(PGM)catalysts creates a barrier for the large-scale application of PEMFC.Tremendous efforts have been devoted to the development of low-cost PGM-free catalysts,especially the Fe-N-C catalysts,to replace the expensive PGM catalysts.However,the characterization methods and evaluation standards of the catalysts varies,which is not conducive to the comparison of PGM-free catalysts.U.S.Department of energy(DOE)is the only authority that specifies the testing standards and activity targets for PGM-free catalysts.In this review,the major breakthroughs of Fe-N-C catalysts are outlined with the reference of DOE standards and targets.The preparation and characteristics of these highly active Fe-N-C catalysts are briefly introduced.Moreover,the efforts on improving the mass transfer and the durability issue of Fe-N-C fuel cell are discussed.Finally,the prospective directions concerning the comprehensive evaluation of the Fe-N-C catalysts are proposed.展开更多
This study examines the development and trends of China’s alfalfa market and imports, identifies key factors for the rapid increase in China’s alfalfa imports, and discusses potential impacts of the U.S.-China trade...This study examines the development and trends of China’s alfalfa market and imports, identifies key factors for the rapid increase in China’s alfalfa imports, and discusses potential impacts of the U.S.-China trade dispute and retaliations on the alfalfa markets and trade in both nations. China’s rapid transition toward larger-scale commercial dairy production, with enhanced feed and cost management as well as quality and safety control, and its limited resources for high-quality alfalfa production are key factors for the dramatic increase in its alfalfa imports, from 19 601 metric tons in 2008 to 1.38 million metric tons(mmt) in 2018. While the United States dominated China’s alfalfa imports with an average share of 97.01% from 2007 to 2017, the share dropped to 83.76% in 2018 and 63.28% in January 2019 due to the trade dispute and retaliations started in 2018. China will likely remain a large importer of alfalfa because of both its growing demand and the comparative advantages of imported alfalfa in quality and price, but the imports from the United States will be highly affected by the ongoing trade dispute and negotiations. China is also expected to make more efforts to reduce its dependence on U.S. alfalfa through increased investment in domestic alfalfa production and identification of alternative sources of alfalfa and other hay imports.展开更多
文摘In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to examine associations between h/day sitting,meeting (or not meeting) the U.S.Physical Activity Guidelines of≥150 min/week of moderate-and vigorous-intensity LTPA,and combinations of sitting time and LTPA on totaland trunk percent body fat (BF%).
文摘This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to enhance healthcare outcomes and reduce disparities,there is a growing concern that these technologies may inadvertently/advertently exacerbate existing racial inequalities.Focusing specifically on the experiences of Black patients,this research investigates how the following AI components:medical algorithms,machine learning,and natural learning processes are contributing to the unequal distribution of medical resources,diagnosis,and health care treatment of those classified as Black.Furthermore,this review employs a multidisciplinary approach,combining insights from computer science,medical ethics,and social justice theory to analyze the mechanisms through which AI systems may encode and reinforce racial biases.By dissecting the three primary components of AI,this paper aims to present a clear understanding of how these technologies work,how they intersect,and how they may inherently perpetuate harmful stereotypes resulting in negligent outcomes for Black patients.Furthermore,this paper explores the ethical implications of deploying AI in healthcare settings and calls for increased transparency,accountability,and diversity in the development and implementation of these technologies.Finally,it is important that I prefer the following paper with a clear and concise definition of what I refer to as Anti-Black racism throughout the text.Therefore,I assert the following:Anti-Black racism refers to prejudice,discrimination,or antagonism directed against individuals or communities of African descent based on their race.It involves the belief in the inherent superiority of one race over another and the systemic and institutional practices that perpetuate inequality and disadvantage for Black people.Furthermore,I proclaim that this form of racism can be manifested in various ways,such as unequal access to opportunities,resources,education,employment,and fair treatment within social,economic,and political systems.It is also pertinent to acknowledge that Anti-Black racism is deeply rooted in historical and societal structures throughout the U.S.borders and beyond,leading to systemic disadvantages and disparities that impact the well-being and life chances of Black individuals and communities.Addressing Anti-Black racism involves recognizing and challenging both individual attitudes and systemic structures that contribute to discrimination and inequality.Efforts to combat Anti-Black racism include promoting awareness,education,advocacy for policy changes,and fostering a culture of inclusivity and equality.
文摘The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the process of adjustment to student life in Taiwan.Under investigation were cultural adjustment and coping skills as these students transitioned from West to East.Qualitative data were collected from interviews with participants and faculty members as well as participant observations.Results indicated that U.S.students found their own ways to acclimate to their new academic setting as well as to social relations,cross-cultural issues,and the linguistic environment in Taiwan to achieve effective adaptation.They made changes in themselves to cope with all situations they encountered.This study provides suggestions for international students abroad in Taiwan,for the Taiwan Residents government,and for universities or colleges in terms of what they should offer to current and future international students.
文摘The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along with their colleagues in the House of Representatives and require the popular social media app TikTok to be sold to an American company.If they do endorse the House vote,then ByteDance must divest itself of TikTok or see the app will be banned on U.S.-based social media platforms.
文摘On January 5,the Chinese People's Association for Friendship with Foreign Countries and the Chinese People's Institute of Foreign Affairs jointly hosted a reception commemorating the 45th anniversary of the establishment of diplomatic relationship between China and the United States in Beijing.Member of the Political Bureau of the CPC Central Committee and Foreign Minister Wang Yi attended the commemoration and delivered aspeech.David Meale,ChargédAffaires at the U.S.Embassy in China,addressed the reception.He extended on behalf of the U.S.side congratulations on the anniversary,expressing the readiness of the U.S.to implement the consensus reached by the two heads of state and promote the steady development of U.S.-China relations.More than 350 people from all walks of life of both countries attended the reception.
文摘The United States passed the Better Utilization of Investment Leading to Development(BUILD Act),as a counterweight to China’s overseas development activities.Under the Act,the US established a new federal agency,the U.S.International Development Finance Corporation(DFC),to enhance U.S.development financing capabilities.To better understand the impact of the DFC on China’s development finance,this article analyzes the DFC’s purpose,functions,structure,and funding.Then it focuses on the purpose of establishing the DFC,providing a preliminary analysis of the potential motivation for its establishment.It also compares the China Development Bank(CDB)and the DFC based on their focused sectors.Finally,through an in-depth analysis of financial frictions in China-U.S.relations,this article argues that the DFC competes with China’s overseas development financing activities in the context of broader strategic competition between China and the U.S.
文摘Since the 1960s,the global natural gas industry has developed rapidly,and natural gas has become a fossil fuel that can balance supply stability,economic efficiency of consumption,clean and low-carbon features at the current stage.However,there is a regional imbalance in the global demand for natural gas,and the continuous rise in geopolitical risks negatively affects the stability of the natural gas market.In recent years,LNG export capacity in the U.S.has continued to grow,and the potential for China-U.S.LNG trade in the future is enormous.From the perspective of development opportunities,strengthening LNG trade cooperation with the U.S.is conducive to the diversification of natural gas import sources for China.From the perspective of challenges,China-U.S.LNG trade cooperation also involves potential risks in terms of economy and channels.
文摘The global supply chain is based on the global distribution of materials,technology,capital,labor,and markets and thus cannot be altered by political motives.KEEPING a sound and stable global supply chain will benefit not only China and America,but also the world at large.Janet Yellen,U.S.secretary of treasury,has realized the devastating consequences of decoupling U.S.economy from Chinese economy when she spoke at John Hopkins Institute on April 20,2023.Yellen said,“The United States will assert ourselves when our vital interests are at stake.But we do not seek to decouple our economy from China’s.A full separation of our economies would be disastrous for both countries.It would be destabilizing for the rest of the world.”
文摘At 1:35 p.m.local time on November 15,a four-hour summit between Chinese President Xi Jinping and U.S.President Joe Biden concluded at Filoli Estate in San Francisco.At a press briefing after the meeting,Wang Yi,member of the Political Bureau of the CPC Central Committee and Minister of Foreign Affairs,said that“the two presidents had a very good,comprehensive,and in-depth meeting.”
文摘Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has naturally endowed this region with different varieties of marble deposits. These marble deposits need proper characterization to ensure their proper use in the construction industry. This research aims to conduct a preliminary study for the characterization of the Nasir Abad Hunza marble deposit. Samples from said deposit were subjected to different tests to study its chemical, physical and mechanical properties. Results of XRF analysis reveal that the deposit under study is dolomitic. The comparison of different physical properties of deposits with standard values confirms its originality. However, high variation in the strength of core samples was observed, which could result from incomplete crystallization by metamorphism. This variation in the strength of samples suggests strength-based definitions of deposit domains to propose the use of each domain separately.
文摘语言作为人类精神的产物和文明的载体应具有审美价值,而演讲作为一种特殊的语言表现形式,它的审美价值在于能够使受众在愉悦中自觉地去接受或容纳演讲的主旨。Speech on Hitler’s Invasion of the U.S.S.R.是丘吉尔政治生涯中重要的演讲作品之一,既具有时效性和实效性,又具有历久弥新的语言审美价值。
文摘This paper analyzes the corn production cost in China, the U.S. and Brazil from 1997 to 2014. According to the results,(1) corn production cost in China is the highest among these three countries;(2) the rapid growth of labor cost and land cost is the major factor that promotes the increase of total corn production cost in China;(3) the level of agricultural mechanization in China has been gradually improving, and the gap between agricultural mechanization levels in China and other two countries is constantly narrowing;(4) differing from the U.S. and Brazil,China exhibits a "high input, low output" agricultural production mode. Based on the above analyses, corresponding suggestions have been presented to reduce corn production cost in China.
文摘AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.
文摘Apoptosis is a form of genetically programmed cell death, which plays a key role in regulation of cellularity in a variety of tissue and cell types including the cardiovascular tissues. Under both physiological and pathophysiological conditions, various biophysiological and biochemical factors, including mechanical forces, reactive oxygen and nitrogen species, cytokines, growth factors, oxidized lipoproteins, etc., may influence apoptosis of vascular cells. The Fas/Fas ligand/caspase death-signaling pathway, Bcl-2 protein family/mitochondria, the tumor suppressive gene p53, and the proto-oncogene c-myc may be activated in atherosclerotic lesions, and mediates vascular apoptosis during the development of atherosclerosis. Abnormal expression and dysfunction of these apoptosis-regulating genes may attenuate or accelerate vascular cell apoptosis and affect the integrity and stability of atherosclerotic plaques. Clarification of the molecular mechanism that regulates apoptosis may help design a new strategy for treatment of atherosclerosis and its major complication, the acute vascular syndromes.
基金Sanming Project of Medicine in Shenzhen(No.SZSM201911015)。
文摘Objective:China and the United States(the U.S.)have the heaviest colorectal cancer(CRC)burden with considerable variations in temporal trends.This study aims to analyze the temporal patterns of CRC burden and its risk factors in China and the U.S.across the past three decades.Methods:Data were extracted from the Global Burden of Disease(GBD)Study in 2019,including cases,deaths,disability-adjusted life-years(DALYs),age-standardized rate(ASR),and summary exposure value(SEV)of CRC in China and the U.S.between 1990 and 2019.Annual average percentage changes(AAPCs)of CRC burden were calculated using the Joinpoint regression model.The mortality in CRC attributable to potential risk factors was characterized by countries,gender,and age groups.Results:In 2019,there were 607,900 and 227,241 CRC cases,and 261,777 and 84,026 CRC deaths in China and the U.S.,respectively.The age-standardized incidence rate(ASIR)was 30.55 per 100,000 in China and 41.86 per100,000 in the U.S.,and the age-standardized mortality rate(ASMR)was 13.86 per 100,000 in China and 14.77 per100,000 in the U.S.CRC incidence,mortality,and DALY rate in the U.S.showed downward trends in the past three decades(AAPC=-0.47,-1.06,and-0.88,respectively),while upward trends were observed in China(AAPC=3.11,1.05,and 0.91,respectively).Among the cause of CRC,the leading risk factor contributing to CRC death was low milk in China and smoking in the U.S.,respectively.Conclusions:From 1990 to 2019,the burden of CRC in China increased dramatically,particularly for males and middle-aged and elderly people.The management of the major risk factors associated with the high burden of CRC should be enhanced.
基金supported by the National Thousand Talents Plan of Chinathe National Natural Science Foundation of China(Grant Nos.21673014 and U1766216)+1 种基金the 111 project(B17002)funded by the Ministry of Education of Chinathe Fundamental Research Funds for the Central Universities of China
文摘Proton exchange membrane fuel cells(PEMFC)have attracted much attention because of their high energy conversion efficiency,high power density and zero emission of pollutants.However,the high cost of the cathode platinum group metal(PGM)catalysts creates a barrier for the large-scale application of PEMFC.Tremendous efforts have been devoted to the development of low-cost PGM-free catalysts,especially the Fe-N-C catalysts,to replace the expensive PGM catalysts.However,the characterization methods and evaluation standards of the catalysts varies,which is not conducive to the comparison of PGM-free catalysts.U.S.Department of energy(DOE)is the only authority that specifies the testing standards and activity targets for PGM-free catalysts.In this review,the major breakthroughs of Fe-N-C catalysts are outlined with the reference of DOE standards and targets.The preparation and characteristics of these highly active Fe-N-C catalysts are briefly introduced.Moreover,the efforts on improving the mass transfer and the durability issue of Fe-N-C fuel cell are discussed.Finally,the prospective directions concerning the comprehensive evaluation of the Fe-N-C catalysts are proposed.
基金the Vermont Agricultural Experiment Station at the University Vermont,USA,and the National Social Science Fund of China(17ZDA067)for financial support of this project。
文摘This study examines the development and trends of China’s alfalfa market and imports, identifies key factors for the rapid increase in China’s alfalfa imports, and discusses potential impacts of the U.S.-China trade dispute and retaliations on the alfalfa markets and trade in both nations. China’s rapid transition toward larger-scale commercial dairy production, with enhanced feed and cost management as well as quality and safety control, and its limited resources for high-quality alfalfa production are key factors for the dramatic increase in its alfalfa imports, from 19 601 metric tons in 2008 to 1.38 million metric tons(mmt) in 2018. While the United States dominated China’s alfalfa imports with an average share of 97.01% from 2007 to 2017, the share dropped to 83.76% in 2018 and 63.28% in January 2019 due to the trade dispute and retaliations started in 2018. China will likely remain a large importer of alfalfa because of both its growing demand and the comparative advantages of imported alfalfa in quality and price, but the imports from the United States will be highly affected by the ongoing trade dispute and negotiations. China is also expected to make more efforts to reduce its dependence on U.S. alfalfa through increased investment in domestic alfalfa production and identification of alternative sources of alfalfa and other hay imports.