The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have bee...The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.展开更多
Introduction:Eliminating hepatitis B virus(HBV)as a major public health threat is a global health priority that requires cost-effective screening strategies.This study evaluated the cost-effectiveness of sequential bi...Introduction:Eliminating hepatitis B virus(HBV)as a major public health threat is a global health priority that requires cost-effective screening strategies.This study evaluated the cost-effectiveness of sequential birth cohort HBV screening strategies in China.Methods:Using a Markov model,we compared five screening strategies with current practice,calculating HBV-related deaths averted,qualityadjusted life years(QALYs)gained,and incremental cost-effectiveness ratios(ICER).One-way deterministic and probabilistic sensitivity analyses were conducted to evaluate the robustness of the results.Results:The sequential birth cohort screening strategy(Sequential Screening 1:screening the 1991–2000 cohort in 2025–2026,the 1971–1990 cohort in 2027–2028,and the 1951–1970 cohort in 2029–2030)was the most cost-effective,with an ICER of 58,523 Chinese Yuan(CNY)per QALY at a willingness-to-pay threshold of three times the percapita Gross Domestic Product(GDP).An alternative strategy that prioritized the 1951–1970 cohort in 2025–2026 averted the most HBV-related deaths(approximately 3.44 million)and gained 24.9 million QALYs,with an ICER of 60,113 CNY per QALY,also showing cost-effectiveness.Discussion:Our findings support sequential birth cohort screening as an optimal and innovative approach to achieving the WHO HBV elimination targets,offering evidence-informed guidance for policymakers to optimize screening programs and resource allocation.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12534013,12047561,and 12104507)the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)the National University of Defense Technology Research Fund Project.
文摘The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.
文摘Introduction:Eliminating hepatitis B virus(HBV)as a major public health threat is a global health priority that requires cost-effective screening strategies.This study evaluated the cost-effectiveness of sequential birth cohort HBV screening strategies in China.Methods:Using a Markov model,we compared five screening strategies with current practice,calculating HBV-related deaths averted,qualityadjusted life years(QALYs)gained,and incremental cost-effectiveness ratios(ICER).One-way deterministic and probabilistic sensitivity analyses were conducted to evaluate the robustness of the results.Results:The sequential birth cohort screening strategy(Sequential Screening 1:screening the 1991–2000 cohort in 2025–2026,the 1971–1990 cohort in 2027–2028,and the 1951–1970 cohort in 2029–2030)was the most cost-effective,with an ICER of 58,523 Chinese Yuan(CNY)per QALY at a willingness-to-pay threshold of three times the percapita Gross Domestic Product(GDP).An alternative strategy that prioritized the 1951–1970 cohort in 2025–2026 averted the most HBV-related deaths(approximately 3.44 million)and gained 24.9 million QALYs,with an ICER of 60,113 CNY per QALY,also showing cost-effectiveness.Discussion:Our findings support sequential birth cohort screening as an optimal and innovative approach to achieving the WHO HBV elimination targets,offering evidence-informed guidance for policymakers to optimize screening programs and resource allocation.
