GaAs multiple concentric nano-ring structures(CNRs)are prepared with multistep crystallization procedures by droplets epitaxy on GaAs(001)to explore the influence of different initial crystallization temperatures on C...GaAs multiple concentric nano-ring structures(CNRs)are prepared with multistep crystallization procedures by droplets epitaxy on GaAs(001)to explore the influence of different initial crystallization temperatures on CNRs morphology.Atomic force microscope(AFM)images show that GaAs nanostructures are more likely to form elliptical rings due to diffusion anisotropy.Meanwhile,with the increase of initial crystallization temperature,the inner ring height and density of CNRs are increased,and outer rings are harder to form.In addition,the mechanism of formation of CNRs is discussed by classical nucleation theory and diffusion theory.The method can be used to calculate the diffusion activation energy of gallium atoms(0.7±0.1 eV)on the GaAs(001)surface conveniently.展开更多
Background:Evidence indicates that low muscle strength is associated with an increased cardiovascular diseases(CVDs)risk.However,the association between muscle strength changes based on repeated measurements and CVD i...Background:Evidence indicates that low muscle strength is associated with an increased cardiovascular diseases(CVDs)risk.However,the association between muscle strength changes based on repeated measurements and CVD incidence remains unclear.Methods:The study used data from the China Health and Retirement Longitudinal Study in 2011(Wave 1),2013(Wave 2),2015(Wave 3),and 2018(Wave 4).Low muscle strength was defined as handgrip strength<28 kg for men or<18 kg for women,or chair-rising time≥12 s.Based on changes in muscle strength from Waves 1 to 2,participants were categorized into four groups of Normal-Normal,Low-Normal,Normal-Low,and Low-Low.CVD events,including heart disease and stroke,were recorded using a self-reported questionnaire during Waves 3 and 4 visits.Cox proportional hazards models were used to investigate the association between muscle strength changes and CVD incidence after multivariable adjustments.Hazard ratios(HRs)and 95%confidence intervals(95%CIs)were estimated with the Normal-Normal group as the reference.Results:A total of 1164 CVD cases were identified among 6608 participants.Compared to participants with sustained normal muscle strength,the CVD risks increased progressively across groups of the Low-Normal(HR=1.20,95%CI:1.01-1.43),the Normal-Low(HR=1.35,95%CI:1.14-1.60),and the Low-Low(HR=1.76,95%CI:1.49-2.07).Similar patterns were observed for the significant associations between muscle strength status and the incidence risks of heart disease and stroke.Subgroup analyses showed that the significant associations between CVD and muscle strength changes were consistent across age,sex,and body mass index(BMI)categories.Conclusions:The study found that muscle strength changes were associated with CVD risk.This suggests that continuous tracking of muscle status may be helpful in screening cardiovascular risk.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61564002 and 11664005)the Science and Technology Foundation of Guizhou Province,China(Grant No.QKH-[2017]1055)Guizhou University Talent Foundation(Grant No.GDJHZ-[2015]23)。
文摘GaAs multiple concentric nano-ring structures(CNRs)are prepared with multistep crystallization procedures by droplets epitaxy on GaAs(001)to explore the influence of different initial crystallization temperatures on CNRs morphology.Atomic force microscope(AFM)images show that GaAs nanostructures are more likely to form elliptical rings due to diffusion anisotropy.Meanwhile,with the increase of initial crystallization temperature,the inner ring height and density of CNRs are increased,and outer rings are harder to form.In addition,the mechanism of formation of CNRs is discussed by classical nucleation theory and diffusion theory.The method can be used to calculate the diffusion activation energy of gallium atoms(0.7±0.1 eV)on the GaAs(001)surface conveniently.
基金Fundamental Research Funds for Higher Education of Tianjin Municipal Education Commission(No.2021ZD038)
文摘Background:Evidence indicates that low muscle strength is associated with an increased cardiovascular diseases(CVDs)risk.However,the association between muscle strength changes based on repeated measurements and CVD incidence remains unclear.Methods:The study used data from the China Health and Retirement Longitudinal Study in 2011(Wave 1),2013(Wave 2),2015(Wave 3),and 2018(Wave 4).Low muscle strength was defined as handgrip strength<28 kg for men or<18 kg for women,or chair-rising time≥12 s.Based on changes in muscle strength from Waves 1 to 2,participants were categorized into four groups of Normal-Normal,Low-Normal,Normal-Low,and Low-Low.CVD events,including heart disease and stroke,were recorded using a self-reported questionnaire during Waves 3 and 4 visits.Cox proportional hazards models were used to investigate the association between muscle strength changes and CVD incidence after multivariable adjustments.Hazard ratios(HRs)and 95%confidence intervals(95%CIs)were estimated with the Normal-Normal group as the reference.Results:A total of 1164 CVD cases were identified among 6608 participants.Compared to participants with sustained normal muscle strength,the CVD risks increased progressively across groups of the Low-Normal(HR=1.20,95%CI:1.01-1.43),the Normal-Low(HR=1.35,95%CI:1.14-1.60),and the Low-Low(HR=1.76,95%CI:1.49-2.07).Similar patterns were observed for the significant associations between muscle strength status and the incidence risks of heart disease and stroke.Subgroup analyses showed that the significant associations between CVD and muscle strength changes were consistent across age,sex,and body mass index(BMI)categories.Conclusions:The study found that muscle strength changes were associated with CVD risk.This suggests that continuous tracking of muscle status may be helpful in screening cardiovascular risk.
