In this note,we prove a logarithmic Sobolev inequality which holds for compact submanifolds without a boundary in manifolds with asymptotically nonnegative sectional curvature.Like the Michale-Simon Sobolev inequality...In this note,we prove a logarithmic Sobolev inequality which holds for compact submanifolds without a boundary in manifolds with asymptotically nonnegative sectional curvature.Like the Michale-Simon Sobolev inequality,this inequality contains a term involving the mean curvature.展开更多
Background Healthcare workers fighting against the coronavirus disease 2019(COVID-19)pandemic are under tremendous pressure,which puts them at an increased risk of developing psychological problems.Aims This study aim...Background Healthcare workers fighting against the coronavirus disease 2019(COVID-19)pandemic are under tremendous pressure,which puts them at an increased risk of developing psychological problems.Aims This study aimed to investigate the prevalence of psychological problems in different healthcare workers(ie,physicians,medical residents,nurses,technicians and public health professionals)during the COVID-19 pandemic in China and explore factors that are associated with the onset of psychological problems in this population during this public health crisis.Methods A cross-sectional,web-based survey was conducted in February 2020 among healthcare workers during the COVID-19 pandemic.Psychological problems were assessed using the Generalized Anxiety Disorder Scale,Patient Health Questionnaire and Insomnia Severity Index.Logistic regression analyses were used to explore the factors that were associated with psychological problems.Results The prevalence of symptoms of anxiety,depression,insomnia and the overall psychological problems in healthcare workers during the COVID-19 pandemic in China was 46.04%,44.37%,28.75%and 56.59%,respectively.The prevalence of the overall psychological problems in physicians,medical residents,nurses,technicians and public health professionals was 60.35%,50.82%,62.02%,57.54%and 62.40%,respectively.Compared with healthcare workers who did not participate in front-line work,front-line healthcare workers had a higher risk of anxiety,insomnia and overall psychological problems.In addition,attention to negative or neutral information about the pandemic,receiving negative feedback from families and friends who joined front-line work,and unwillingness to join front-line work if given a free choice were three major factors for these psychological problems.Conclusions Psychological problems are pervasive among healthcare workers during the COVID-19 pandemic.Receiving negative information and participating in front-line work appear to be.important risk factors for psychological problems.The psychological health of different healthcare workers should be protected during the COVID-19 pandemic with timely interventions and proper information feedback.展开更多
Background Early screening of cognitive function is critical to dementia treatment and care.However,traditional tests require face-to-face administration and are often limited by implementation costs and biases.Aims T...Background Early screening of cognitive function is critical to dementia treatment and care.However,traditional tests require face-to-face administration and are often limited by implementation costs and biases.Aims This study aimed to assess whether the Thoven Cognitive Self-Assessment(TCSA),a novel,innovative two-step touchscreen-based cognition assessment tool,could identify early cognitive impairment due to dementia in older adults.Methods The TCSA was administered to 61 healthy controls(HCs),46 participants with mild cognitive impairment(MCI)and 44 participants diagnosed with dementia recruited from Shanghai.Two outcome measures were generated from the TCSA test:the TCSA_(primary task)score and the TCSA_(secondary task)score.Results The total average scores in the control group for the TCSA_(primary task)and TCSA_(secondary task)were significantly higher than those in the MCI and dementia groups(TCSA_(primary task):HCs vs MCI group vs dementia group,8.58±1.76 vs 5.40±2.67 vs 2.74±2.11,F=75.40,p<0.001;TCSA_(secondary task):HCs vs MCI group vs dementia group,23.02±3.31 vs 17.95±4.93 vs 11.93±5.50,F=76.46,p<0.001).Moreover,receiver operating characteristic analysis showed that a score below 7.5 for the TCSA_(primary task)and a score below 22.5 for the TCSA_(secondary task)were indicators of MCI.Conclusions The TCSA appears to be efficacious for the detection of cognitive impairment in older adults.It demonstrates the potential for large-scale cognition screening in community service settings.展开更多
Background Family environments can shape children’s personalities and social networks,rendering distinguishing adverse childhood experiences(ACEs)from family and society essential,but related evidence remains limited...Background Family environments can shape children’s personalities and social networks,rendering distinguishing adverse childhood experiences(ACEs)from family and society essential,but related evidence remains limited.Aims This cross-sectional study aimed to investigate the correlations between intrafamilial and social ACEs,their associations with depressive symptoms and cognitive impairment and the(education-moderated)mediating role of social ACEs.Methods Data for this cross-sectional study were from the China Health and Retirement Longitudinal Study.Nine intrafamilial(0,1,2,3,and 4 or more)and three social(0,1,and 2 or more)ACEs were identified.Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depression Scale.Global cognition,including episodic memory and mental intactness,was calculated as z scores.Binary and ordered logistic regressions,generalised linear models with Gaussian family and identity link,and mediation analysis were used.Results 13435 participants aged 59.0(51.0–66.0)were included.Compared with participants with no intrafamilial ACEs,those with 1,2,3,and 4 or more intrafamilial ACEs tended to develop more social ACEs,with odds ratios(ORs)of 1.55(95%confidence interval(CI):1.36 to 1.76),2.36(95%CI:2.08 to 2.68),3.46(95%CI:3.02 to 3.96)and 6.10(95%CI:5.30 to 7.02),respectively.Both intrafamilial and social ACEs were associated with depressive symptoms(OR>3 for four or more intrafamilial ACEs and two or more social ACEs)and global cognition(β=−0.26 for four or more intrafamilial ACEs andβ=−0.29 for two or more social ACEs).Social ACEs mediated the associations of intrafamilial ACEs with depressive symptoms and global cognition by 12.3%and 13.1%,respectively.Furthermore,as education levels increased,the impact of intrafamilial ACEs on depressive symptoms was increasingly mediated through social ACEs,while the mediating role of social ACEs between intrafamilial ACEs and cognitive impairment gradually diminished.Conclusions Improving children’s social environments and elevating general education can prevent later-life depressive symptoms and cognitive impairment attributed to ACEs in China.展开更多
BACKGROUND Epidemiologic studies have explored the association between a single cardiovascular risk factor(CVRF)and resting heart rate(RHR),but the research on the relation of multiple risk factors with RHR remains sc...BACKGROUND Epidemiologic studies have explored the association between a single cardiovascular risk factor(CVRF)and resting heart rate(RHR),but the research on the relation of multiple risk factors with RHR remains scarce.This study aimed to explore the associations between CVRFs clustering and the risk of elevated RHR.METHODS In this cross-sectional study,adults aged 35-75 years from 31 provinces were recruited by the China PEACE Million Persons Projects from September 2015 to August 2020.We focused on seven risk factors:hypertension,diabetes mellitus,dyslipidemia,obesity,smoking,alcohol use,and low physical activity.Multivariate logistic regression was used to calculate odds ratios(OR)for elevated RHR(>80 beats/min).RESULTS Among 1,045,405 participants,the mean age was 55.67±9.86 years,and 60.4%of participants were women.The OR(95%CI)for elevated RHR for the groups with 1,2,3,4 and≥5 risk factor were 1.11(1.08-1.13),1.36(1.33-1.39),1.68(1.64-1.72),2.01(1.96-2.07)and 2.58(2.50-2.67),respectively(Ptrend<0.001).The association between the CVRFs clustering number and elevated RHR was much more pronounced in young males than in other age-sex subgroups.Clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR than those comprising more behavioral risk factors.CONCLUSIONS There was a significant positive association between the CVRFs clustering number and the risk of elevated RHR,particularly in young males.Compared clusters comprising more behavioral risk factors,clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR.RHR may serve as an indicator of the cumulative effect of multiple risk factors.展开更多
BACKGROUND Older men are more vulnerable to fatal falls than women,and gait disturbances contribute to the risk of falls.Studies have assessed the association between arterial stiffness and gait dysfunction,but the re...BACKGROUND Older men are more vulnerable to fatal falls than women,and gait disturbances contribute to the risk of falls.Studies have assessed the association between arterial stiffness and gait dysfunction,but the results have been inconclusive.This study aimed to conduct a cross-sectional analysis to evaluate the association between brachial–ankle pulse wave velocity(baPWV)and gait assessment in older men.METHODS Data from the 2014–2015 Korea Institute of Sport Science Fitness Standards project were used for the analysis.The inclusion criteria were men aged>65 years with gait assessment[the 30-s chair stand test(30s-CST),the timed up and go(TUG)test,the figure-of-8 walk(F8W)test,the 2-min step test(2MST),and the 6-min walk test(6MWT)]and baPWV measurement data.Generalized linear regression analysis was conducted with multiple confounding factor adjustments,including lower extremity isometric strength.RESULTS A total of 291 participants were included in the analysis.The mean age was 71.38±4.40 years.The mean values were as follows:(1)30s-CST,17.48±5.00;(2)TUG test,6.01±1.10 s;(3)F8W test,25.65±4.71 s;(4)2MST,102.40±18.83 per 2 min;and(5)6MWT,500.02±85.65 m.After multivariable adjustment,baPWV was associated with the 6MWT(β=−0.037,95%CI:−0.072–−0.002),TUG test(β=0,95%CI:0.000–0.001),and F8W test(β=0.002,95%CI:0.000–0.004).baPWV was not associated with the 30s-CST and 2MST.CONCLUSIONS The current study showed a statistically significant association between gait assessments and arterial stiffness,independent of lower extremity strength.However,this association was modest.Future prospective studies are needed to elucidate the complex relationship between arterial stiffness and gait dysfunction.展开更多
Background Comorbidity of irritable bowel syndrome(IBS)and psychiatric disorders is common,and the prevalence of at least one psychiatric disorder has been reported as high as 80%among patients with IBS.Aims To explor...Background Comorbidity of irritable bowel syndrome(IBS)and psychiatric disorders is common,and the prevalence of at least one psychiatric disorder has been reported as high as 80%among patients with IBS.Aims To explore the association of anxiety-depressive disorders with IBS and its different subtypes,and to evaluate the associations of lifestyle habits,dietary habits and sleeping quality with IBS.Methods A comparative cross-sectional study was conducted at the AL-Mahsama Family Practice Center,Ismailia,Egypt.It was carried out between October 2019 and October 2020.Participants were categorised into 175 patients with IBS,diagnosed using the Rome IV criteria,and 175 patients without IBS.A semistructured questionnaire was used to collect data on sociodemographic characteristics,lifestyle habits,dietary habits and sleep quality from both groups.The Hamilton Anxiety Rating Scale was used to assess anxiety symptoms,whereas the Beck Depression Inventory Second Edition was used to assess depression symptoms.Results There was a high statistically significant difference between both groups with regard to age,education,occupation and socioeconomic status(SES),being a smoker,being physically inactive,having sleep disturbance and having irregular meals;being either obese or overweight was more reported in the IBS group.There was a high statistically significant difference in the rate of anxiety and depression between patients with and without IBS.Mild,moderate and severe anxiety were reported in 37.1%,42.9%and 20.0%of patients with IBS while most(80.0%)of the patients without IBS reported mild anxiety.Regarding depression,mild,moderate and severe depression were reported in 60.0%,14.3%and 25.7%of the patients with IBS while most(82.9%)of the non-IBS participants reported mild depression.Conclusions The study shows a significant association between anxiety-depressive disorders and IBS,but no significant associations between anxiety-depressive disorders and IBS subtypes.展开更多
OBJECTIVE To examine whether difficulty of falling asleep(DoFA)is associated with non-high-density lipoprotein cholesterol(non-HDL-C)level among Canadian older adults.METHODS 26,954 individuals aged 45-85 years from t...OBJECTIVE To examine whether difficulty of falling asleep(DoFA)is associated with non-high-density lipoprotein cholesterol(non-HDL-C)level among Canadian older adults.METHODS 26,954 individuals aged 45-85 years from the baseline data of the Canadian Longitudinal Study for Aging were in-cluded in this study.DoFA was categorized into five groups by answer to the question“Over the last month,how often did it take you more than 30 min to fall asleep?”Response options are“Never,<1 time/week,1−2 times/week,3−5 times/week,or 6−7 times/week”.Non-HDL-C,the difference of total cholesterol and HDL-C,were categorized into five categories based on these cut-offs(<2.6 mmol/L,2.6−3.7 mmol/L,3.7−4.8 mmol/L,4.8−5.7 mmol/L,and≥5.7 mmol/L).Ordinal logistic regression(logit link)continuation ratio models were used to estimate the odds of higher non-HDL-C levels for DoFA status.Adjusted means of non-HDL-C by DoFA status were estimated by general linear models.All analyses were sex separately using analytic weights to en-sure generalizability.RESULTS The proportions of DoFA in five categories were 41.6%,25.7%,13.6%,9.4%,9.7%for females and 52.9%,24.9%,10.5%,6.1%,5.6%for males,respectively.After adjustment of demographical and other covariates(such as depression,comorbidity,sleeping hour,etc.)compared to those who reported never having DoFA,the ORs(95%CIs)of higher levels of non-HDL-C for those whose DoFA status in<1 time/week,1−2 times/week,3−5 times/week,and 6−7 times/week were 1.12(1.05−1.21),1.09(0.99−1.18),1.20(1.09−1.33),1.29(1.17−1.43)in females and 1.05(0.98−1.13),0.95(0.87−1.05),1.21(1.08−1.37),0.97(0.85−1.09)in males,respectively.The adjusted means of non-HDL-C among the five DoFA status were 3.68 mmol/L,3.73 mmol/L,3.74 mmol/L,3.82 mmol/L,3.84 mmol/L for females and 3.54 mmol/L,3.58 mmol/L,3.51 mmol/L,3.69 mmol/L,3.54 mmol/L for males,respectively.CONCLUSIONS The results of this study have identified a risk association pattern between DoFA status and non-HDL-C levels in females but not in males.Further research is needed to confirm these findings.展开更多
Hypertension has been increasingly cited mortality cause in developing countries including Bangladesh,[1–4]and generally associated with coronary artery disease,stroke,heart failure,atrial fibrillation,peripheral vas...Hypertension has been increasingly cited mortality cause in developing countries including Bangladesh,[1–4]and generally associated with coronary artery disease,stroke,heart failure,atrial fibrillation,peripheral vascular disease,vision loss and chronic kidney disease.展开更多
Background The WHO has classified depression as a disease of public concern.Police officers are a particular subpopulation group that is at an increased risk for mental health problems.This study examined the prevalen...Background The WHO has classified depression as a disease of public concern.Police officers are a particular subpopulation group that is at an increased risk for mental health problems.This study examined the prevalence of depression,suicidality and associated risk factors among police officers in urban Tanzania.Aims The aim of this study was to examine the prevalence of depression,suicidality and associated risk factors among police officers in Tanzania.Methods A cross-sectional study was conducted between April 2019 and October 2020 among 550 participants in Dar es Salaam recruited using a multistage cluster sampling technique.The Patient Health Questionnaire-9 was used to screen for depression and suicidality.The Interpersonal Support Evaluation List-12 tool was used to measure perceived social support.Descriptive statistics were summarised using frequencies and percentages.Bivariate and multivariate analyses were used to establish associations between predictors of interest,depression and suicidality.Results There were 497 participants in the study.Of these,76.6%(376 of 491)were men,and the median(IQR)age was 37.0(17)years.Around 19.8%(96 of 486)of the police officers screened positive for depression and 15.4%(75 of 413)for suicidality.A significant proportion was either moderately(29 of 96,30.2%)or severely depressed(8 of 75,10.7%).Of those who experienced suicidal thoughts,10.7%(8 of 75)reported having daily suicidal thoughts.Perceiving low social support was associated with an increased risk of reporting depression(adjusted OR(aOR):28.04,95%CI:8.42 to 93.37,p<0.001)and suicidality(aOR:10.85,95%CI:3.56 to 33.08,p<0.001)as compared with those with high perceived social support.Conclusion The magnitude of depression and suicidality among police officers in urban Tanzania is alarmingly high.The study findings indicate the need for routine screening for depression and suicidality among police officers and design appropriate mental health responsive services in this population.展开更多
We demonstrate that the combined use of differential scanning calorimetry(DSC)and cross-sectional transmission electron microscopy(XTEM)is a powerful technique in the quantitative investigation of the nucleation and g...We demonstrate that the combined use of differential scanning calorimetry(DSC)and cross-sectional transmission electron microscopy(XTEM)is a powerful technique in the quantitative investigation of the nucleation and growth of metastable and equilibrium phases during thin-film interdiffusion reactions.The Various approaches and advantages of the DSC/XTEM technique in obtaining a variety of kinetic and thermodynamic data are discussed.Explosive reactions,as opposed to conventionally controlled reactions,may occur in thin films where the multilayer geometry is used.展开更多
To provide practical and surgical anatomy for the imaging diagnosis and surgical treatment of the disease of the caudate lobe of the liver. Methods： Based on Chinese Visible Human 1-5 data sets and assisted by 3D vis...To provide practical and surgical anatomy for the imaging diagnosis and surgical treatment of the disease of the caudate lobe of the liver. Methods： Based on Chinese Visible Human 1-5 data sets and assisted by 3D visualization and reconstruction, the 3D models of the upper abdomen or the liver were reconstructed and the cross-sectional images were converted to the coronal and sagittal images. The anatomy of the caudate lobe of the liver on the coronal and sagittal planes was investigated on serial planes of the upper abdomen. Results： The caudate lobe was bordered on the left by the fissura ligamenti venosi, posteriorly by the IVC, superiorly by the hepatic veins and inferiorly by the hepatic hilum. Its right and ventral borders might be obscure, with only relative borders existent. The right wall of the IVC was a good landmark to judge the relative realm of paracaval portion, and the relative ventral plane might exist between the hepatic hilum and entrance of hepatic veins. The caudate lobe could be divided into two principal regions： the left Spiegel lobe and the right paracaval portion. The caudate process, and the right rear process occurring in some individuals belonged to the right paracaval portion. The caudate lobe was blood supplied by the portal vein, which directly drained into the IVC. Conclusion： There are not definite borders for the right part of the caudate lobe, and most of the knowledge on it is based on the cast study, which may not suit for the clinical diagnosis and practice. The coronal and sagittal sections can better show the anatomic relationships between the caudate lobe, the other parts of the liver and the adjacent structures. The 3D digital visualization is an accurate and convenient study method for clinical anatomy.展开更多
Background In recent years,energy drinks(EDs)have been widely used among young people around the world.The extensive use of EDs also affects the sleep and exercise of adolescents.Aims This study aimed to investigate t...Background In recent years,energy drinks(EDs)have been widely used among young people around the world.The extensive use of EDs also affects the sleep and exercise of adolescents.Aims This study aimed to investigate the consumption of EDs,the knowledge,attitude towards EDs and associated factors of EDs consumption among adolescents in Shanghai,China.Methods A total of 4608 adolescents completed a self-administered questionnaire assessing EDs use history,knowledge and attitude towards EDs.Adolescent Self-rating Life Events Checklist(ASLEC)was used to assess their life events.All participants were divided into two groups based on whether they used them or not.t-test andχ^(2)test were used to compare the differences between the two groups,and binary logistic regression analysis was used to investigate the related factors for EDs consumption.Results 70.5%of the participants reported having ever used EDs.The main avenues to getting information on EDs were from advertisements.67.56%of them believed that EDs had adverse effects on health.22.09%of the participants and 31.55%of their parents took a negative attitude towards EDs.Compared with the non-consumption group,participants in the consumption group were likely to be male,with older age,identified EDs more correctly and did not believe EDs had adverse effects,with more positive attitude and higher ASLEC score.Logistic regression results showed that gender,age,attitude of parents and themselves,knowledge of EDs and ASLEC score significantly predicted EDs consumption.Conclusion EDs consumption was popular among adolescents in Shanghai,and the tailored intervention programmes need to be developed based on the characteristics of adolescents.展开更多
During the later period of construction of Tianshengqiao concrete faced rockfill dam(CFRD), cracks appeared in the upstream fill slope. The main reason was the nonuniform deformation. The treatment methods were: for c...During the later period of construction of Tianshengqiao concrete faced rockfill dam(CFRD), cracks appeared in the upstream fill slope. The main reason was the nonuniform deformation. The treatment methods were: for cracks with opening less than 1 cm, the cracked slope was compacted with added effort to eliminate cracks; for cracks with opening greater than 1 cm , crack grouting was carried out . The practice demonstrated the treatment was successful. Careful analysis of the relation between sectionalized filling and crack emergence is of significance in guiding the construction design and drawing out filling plan for a high CFRD.展开更多
In the present paper, the authors study totally real 2-harmonic submanifolds in a quasi constant holomorphic sectional curvature space and obtain a Simons＇ type inte- gral inequality of compact submanifoids as well a...In the present paper, the authors study totally real 2-harmonic submanifolds in a quasi constant holomorphic sectional curvature space and obtain a Simons＇ type inte- gral inequality of compact submanifoids as well as some pinching theorems on＇the second fundamental form.展开更多
Based on the Skyrme energy density functional and reaction Q-value,this study proposed an effective nucleus-nucleus poten-tial for describing the capture barrier in heavy-ion fusion processes.The 443 extracted barrier...Based on the Skyrme energy density functional and reaction Q-value,this study proposed an effective nucleus-nucleus poten-tial for describing the capture barrier in heavy-ion fusion processes.The 443 extracted barrier heights were well reproduced with a root-mean-square(RMS)error of 1.53 MeV,and the RMS deviations with respect to 144 time-dependent Hartree-Fock capture barrier heights were only 1.05 MeV.Coupled with the Siwek-Wilczyński formula,wherein three parameters were determined by the proposed effective potentials,the measured capture cross sections at energies around the barriers were reasonably well reproduced for several fusion reactions induced by nearly spherical nuclei as well as by nuclei with large deformations,such as^(154)Sm and^(238)U.The shallow capture pockets and small values of the average barrier radii resulted in the reduction of the capture cross sections for 52,54Cr-and 64 Ni-induced reactions,which were related to the synthesis of new super-heavy nuclei.展开更多
Inelastic collisions are the dominant cause of energy loss in radiotherapy.In the energy range around the Bragg peak,single ionization(SI)and single-electron capture(SC)are the primary inelastic collisions that lead t...Inelastic collisions are the dominant cause of energy loss in radiotherapy.In the energy range around the Bragg peak,single ionization(SI)and single-electron capture(SC)are the primary inelastic collisions that lead to energy loss.This study employs the classical trajectory Monte Carlo method to study the SI and SC processes of H_(2)O molecules using He^(2+) and C^(6+) projectiles in the energy range of 10 keV/u to 10 MeV/u.The total cross sections,single differential cross sections,impact parameter dependence of SI and SC,and fragmentation cross sections were investigated.Results illustrate that the cross section for SI is the highest when the projectile energy is close to the Bragg peak energy.When the projectile energy is below the Bragg peak energy,the ionized electrons in the forward direction dominate,and the removal of electrons can be associated with large impact parameters.As the projectile energy increases,the emission angle of the electrons gradually transitions from small angles(60°~120°)to large angles(60°~120°),and the removal of electrons is associated with small impact parameters.The energy distributions of the ionized electron are similar when the projectile energy is equal to,below or above the Bragg peak energy.The fragmentation cross sections after SI and SC in the energy range around the Bragg peak were also estimated.展开更多
Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early universe.Among these,deuterium...Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early universe.Among these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent reactions.To date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational precision.In this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium abundance.We found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H uncertainty.Currently,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He rate.From the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.展开更多
Based on the dinuclear system model,the calculated evaporation residue cross sections matched well with the current experimental results.The synthesis of superheavy elements Z=121 was systematically studied through co...Based on the dinuclear system model,the calculated evaporation residue cross sections matched well with the current experimental results.The synthesis of superheavy elements Z=121 was systematically studied through combinations of stable projectiles with Z=21-30 and targets with half-lives exceeding 50 d.The influence of mass asymmetry and isotopic dependence on the projectile and target nuclei was investigated in detail.The reactions^(254)Es(^(46)Ti,3n)^(297)121 and^(252)Es(^(46)Ti,3n)^(295)121 were found to be experimentally feasible for synthesizing superheavy element Z=121,with maximal evaporation residue cross sections of 6.619 and 4.123 fb at 219.9 and 223.9 MeV,respectively.展开更多
Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle w...Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle was thought to be the source of the calcium observed in these oldest stars.However,according to the stellar modeling,a nearly tenfold increase in the thermonuclear rate ratio of the break-out ^(19)F(p,γ)^(20) Ne reaction with respect to the competing ^(19)F(p,α)^(16) O back-processing reaction is required to reproduce the observed calcium abundance.We performed a direct measurement of this break-out reaction at the China Jinping underground laboratory.The measurement was performed down to the low-energy limit of E_(c.m.)=186 keV in the center-of-mass frame.The key resonance was observed at 225.2 keV for the first time.At a temperature of approximately 0.1 GK,this new resonance enhanced the thermonuclear ^(19)F(p,γ)^(20) Ne rate by up to a factor of≈7.4,compared with the previously recommended NACRE rate.This is of particular interest to the study of the evolution of the first stars and implies a stronger breakdown in their“warm”CNO cycle through the ^(19)F(p,γ)^(20) Ne reaction than previously envisioned.This break-out resulted in the production of the calcium observed in the oldest stars,enhancing our understanding of the evolution of the first stars.展开更多
基金Supported by the NSFC(11771087,12171091 and 11831005)。
文摘In this note,we prove a logarithmic Sobolev inequality which holds for compact submanifolds without a boundary in manifolds with asymptotically nonnegative sectional curvature.Like the Michale-Simon Sobolev inequality,this inequality contains a term involving the mean curvature.
基金grants from the Beijing Natural Science Foundation(No.7194336)Special Research Fund of PKUHSC for Prevention and Control of COVID-19(No.BMU2020HKYZX008)the National Natural Science Foundation of China(No.81761128036,81821092 and 31900805).
文摘Background Healthcare workers fighting against the coronavirus disease 2019(COVID-19)pandemic are under tremendous pressure,which puts them at an increased risk of developing psychological problems.Aims This study aimed to investigate the prevalence of psychological problems in different healthcare workers(ie,physicians,medical residents,nurses,technicians and public health professionals)during the COVID-19 pandemic in China and explore factors that are associated with the onset of psychological problems in this population during this public health crisis.Methods A cross-sectional,web-based survey was conducted in February 2020 among healthcare workers during the COVID-19 pandemic.Psychological problems were assessed using the Generalized Anxiety Disorder Scale,Patient Health Questionnaire and Insomnia Severity Index.Logistic regression analyses were used to explore the factors that were associated with psychological problems.Results The prevalence of symptoms of anxiety,depression,insomnia and the overall psychological problems in healthcare workers during the COVID-19 pandemic in China was 46.04%,44.37%,28.75%and 56.59%,respectively.The prevalence of the overall psychological problems in physicians,medical residents,nurses,technicians and public health professionals was 60.35%,50.82%,62.02%,57.54%and 62.40%,respectively.Compared with healthcare workers who did not participate in front-line work,front-line healthcare workers had a higher risk of anxiety,insomnia and overall psychological problems.In addition,attention to negative or neutral information about the pandemic,receiving negative feedback from families and friends who joined front-line work,and unwillingness to join front-line work if given a free choice were three major factors for these psychological problems.Conclusions Psychological problems are pervasive among healthcare workers during the COVID-19 pandemic.Receiving negative information and participating in front-line work appear to be.important risk factors for psychological problems.The psychological health of different healthcare workers should be protected during the COVID-19 pandemic with timely interventions and proper information feedback.
基金This study was funded by Key R&D Program of China(Grant number:2017YFC1310500)Shanghai Municipal Health Commission project(Grant number:202040500)Shanghai public health projects(Grant number:GWV-9.2)。
文摘Background Early screening of cognitive function is critical to dementia treatment and care.However,traditional tests require face-to-face administration and are often limited by implementation costs and biases.Aims This study aimed to assess whether the Thoven Cognitive Self-Assessment(TCSA),a novel,innovative two-step touchscreen-based cognition assessment tool,could identify early cognitive impairment due to dementia in older adults.Methods The TCSA was administered to 61 healthy controls(HCs),46 participants with mild cognitive impairment(MCI)and 44 participants diagnosed with dementia recruited from Shanghai.Two outcome measures were generated from the TCSA test:the TCSA_(primary task)score and the TCSA_(secondary task)score.Results The total average scores in the control group for the TCSA_(primary task)and TCSA_(secondary task)were significantly higher than those in the MCI and dementia groups(TCSA_(primary task):HCs vs MCI group vs dementia group,8.58±1.76 vs 5.40±2.67 vs 2.74±2.11,F=75.40,p<0.001;TCSA_(secondary task):HCs vs MCI group vs dementia group,23.02±3.31 vs 17.95±4.93 vs 11.93±5.50,F=76.46,p<0.001).Moreover,receiver operating characteristic analysis showed that a score below 7.5 for the TCSA_(primary task)and a score below 22.5 for the TCSA_(secondary task)were indicators of MCI.Conclusions The TCSA appears to be efficacious for the detection of cognitive impairment in older adults.It demonstrates the potential for large-scale cognition screening in community service settings.
基金This study was funded by the Major Project of the National Social Science Fund of China(21ZDA107)the Fundamental Research Funds for the Central Universities(7101303357).
文摘Background Family environments can shape children’s personalities and social networks,rendering distinguishing adverse childhood experiences(ACEs)from family and society essential,but related evidence remains limited.Aims This cross-sectional study aimed to investigate the correlations between intrafamilial and social ACEs,their associations with depressive symptoms and cognitive impairment and the(education-moderated)mediating role of social ACEs.Methods Data for this cross-sectional study were from the China Health and Retirement Longitudinal Study.Nine intrafamilial(0,1,2,3,and 4 or more)and three social(0,1,and 2 or more)ACEs were identified.Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depression Scale.Global cognition,including episodic memory and mental intactness,was calculated as z scores.Binary and ordered logistic regressions,generalised linear models with Gaussian family and identity link,and mediation analysis were used.Results 13435 participants aged 59.0(51.0–66.0)were included.Compared with participants with no intrafamilial ACEs,those with 1,2,3,and 4 or more intrafamilial ACEs tended to develop more social ACEs,with odds ratios(ORs)of 1.55(95%confidence interval(CI):1.36 to 1.76),2.36(95%CI:2.08 to 2.68),3.46(95%CI:3.02 to 3.96)and 6.10(95%CI:5.30 to 7.02),respectively.Both intrafamilial and social ACEs were associated with depressive symptoms(OR>3 for four or more intrafamilial ACEs and two or more social ACEs)and global cognition(β=−0.26 for four or more intrafamilial ACEs andβ=−0.29 for two or more social ACEs).Social ACEs mediated the associations of intrafamilial ACEs with depressive symptoms and global cognition by 12.3%and 13.1%,respectively.Furthermore,as education levels increased,the impact of intrafamilial ACEs on depressive symptoms was increasingly mediated through social ACEs,while the mediating role of social ACEs between intrafamilial ACEs and cognitive impairment gradually diminished.Conclusions Improving children’s social environments and elevating general education can prevent later-life depressive symptoms and cognitive impairment attributed to ACEs in China.
基金supported by the National Key Research and Development Program from the Ministry of Science and Technology of China(2018YFC1311205).
文摘BACKGROUND Epidemiologic studies have explored the association between a single cardiovascular risk factor(CVRF)and resting heart rate(RHR),but the research on the relation of multiple risk factors with RHR remains scarce.This study aimed to explore the associations between CVRFs clustering and the risk of elevated RHR.METHODS In this cross-sectional study,adults aged 35-75 years from 31 provinces were recruited by the China PEACE Million Persons Projects from September 2015 to August 2020.We focused on seven risk factors:hypertension,diabetes mellitus,dyslipidemia,obesity,smoking,alcohol use,and low physical activity.Multivariate logistic regression was used to calculate odds ratios(OR)for elevated RHR(>80 beats/min).RESULTS Among 1,045,405 participants,the mean age was 55.67±9.86 years,and 60.4%of participants were women.The OR(95%CI)for elevated RHR for the groups with 1,2,3,4 and≥5 risk factor were 1.11(1.08-1.13),1.36(1.33-1.39),1.68(1.64-1.72),2.01(1.96-2.07)and 2.58(2.50-2.67),respectively(Ptrend<0.001).The association between the CVRFs clustering number and elevated RHR was much more pronounced in young males than in other age-sex subgroups.Clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR than those comprising more behavioral risk factors.CONCLUSIONS There was a significant positive association between the CVRFs clustering number and the risk of elevated RHR,particularly in young males.Compared clusters comprising more behavioral risk factors,clusters comprising more metabolic risk factors were associated with a higher risk of elevated RHR.RHR may serve as an indicator of the cumulative effect of multiple risk factors.
基金supported by the Korea Sport Promotion Foundation。
文摘BACKGROUND Older men are more vulnerable to fatal falls than women,and gait disturbances contribute to the risk of falls.Studies have assessed the association between arterial stiffness and gait dysfunction,but the results have been inconclusive.This study aimed to conduct a cross-sectional analysis to evaluate the association between brachial–ankle pulse wave velocity(baPWV)and gait assessment in older men.METHODS Data from the 2014–2015 Korea Institute of Sport Science Fitness Standards project were used for the analysis.The inclusion criteria were men aged>65 years with gait assessment[the 30-s chair stand test(30s-CST),the timed up and go(TUG)test,the figure-of-8 walk(F8W)test,the 2-min step test(2MST),and the 6-min walk test(6MWT)]and baPWV measurement data.Generalized linear regression analysis was conducted with multiple confounding factor adjustments,including lower extremity isometric strength.RESULTS A total of 291 participants were included in the analysis.The mean age was 71.38±4.40 years.The mean values were as follows:(1)30s-CST,17.48±5.00;(2)TUG test,6.01±1.10 s;(3)F8W test,25.65±4.71 s;(4)2MST,102.40±18.83 per 2 min;and(5)6MWT,500.02±85.65 m.After multivariable adjustment,baPWV was associated with the 6MWT(β=−0.037,95%CI:−0.072–−0.002),TUG test(β=0,95%CI:0.000–0.001),and F8W test(β=0.002,95%CI:0.000–0.004).baPWV was not associated with the 30s-CST and 2MST.CONCLUSIONS The current study showed a statistically significant association between gait assessments and arterial stiffness,independent of lower extremity strength.However,this association was modest.Future prospective studies are needed to elucidate the complex relationship between arterial stiffness and gait dysfunction.
文摘Background Comorbidity of irritable bowel syndrome(IBS)and psychiatric disorders is common,and the prevalence of at least one psychiatric disorder has been reported as high as 80%among patients with IBS.Aims To explore the association of anxiety-depressive disorders with IBS and its different subtypes,and to evaluate the associations of lifestyle habits,dietary habits and sleeping quality with IBS.Methods A comparative cross-sectional study was conducted at the AL-Mahsama Family Practice Center,Ismailia,Egypt.It was carried out between October 2019 and October 2020.Participants were categorised into 175 patients with IBS,diagnosed using the Rome IV criteria,and 175 patients without IBS.A semistructured questionnaire was used to collect data on sociodemographic characteristics,lifestyle habits,dietary habits and sleep quality from both groups.The Hamilton Anxiety Rating Scale was used to assess anxiety symptoms,whereas the Beck Depression Inventory Second Edition was used to assess depression symptoms.Results There was a high statistically significant difference between both groups with regard to age,education,occupation and socioeconomic status(SES),being a smoker,being physically inactive,having sleep disturbance and having irregular meals;being either obese or overweight was more reported in the IBS group.There was a high statistically significant difference in the rate of anxiety and depression between patients with and without IBS.Mild,moderate and severe anxiety were reported in 37.1%,42.9%and 20.0%of patients with IBS while most(80.0%)of the patients without IBS reported mild anxiety.Regarding depression,mild,moderate and severe depression were reported in 60.0%,14.3%and 25.7%of the patients with IBS while most(82.9%)of the non-IBS participants reported mild depression.Conclusions The study shows a significant association between anxiety-depressive disorders and IBS,but no significant associations between anxiety-depressive disorders and IBS subtypes.
基金the Government of Canada through the Canadian Institutes of Health Research(CLSA 94473)and the Canada Foundation for Innovation.
文摘OBJECTIVE To examine whether difficulty of falling asleep(DoFA)is associated with non-high-density lipoprotein cholesterol(non-HDL-C)level among Canadian older adults.METHODS 26,954 individuals aged 45-85 years from the baseline data of the Canadian Longitudinal Study for Aging were in-cluded in this study.DoFA was categorized into five groups by answer to the question“Over the last month,how often did it take you more than 30 min to fall asleep?”Response options are“Never,<1 time/week,1−2 times/week,3−5 times/week,or 6−7 times/week”.Non-HDL-C,the difference of total cholesterol and HDL-C,were categorized into five categories based on these cut-offs(<2.6 mmol/L,2.6−3.7 mmol/L,3.7−4.8 mmol/L,4.8−5.7 mmol/L,and≥5.7 mmol/L).Ordinal logistic regression(logit link)continuation ratio models were used to estimate the odds of higher non-HDL-C levels for DoFA status.Adjusted means of non-HDL-C by DoFA status were estimated by general linear models.All analyses were sex separately using analytic weights to en-sure generalizability.RESULTS The proportions of DoFA in five categories were 41.6%,25.7%,13.6%,9.4%,9.7%for females and 52.9%,24.9%,10.5%,6.1%,5.6%for males,respectively.After adjustment of demographical and other covariates(such as depression,comorbidity,sleeping hour,etc.)compared to those who reported never having DoFA,the ORs(95%CIs)of higher levels of non-HDL-C for those whose DoFA status in<1 time/week,1−2 times/week,3−5 times/week,and 6−7 times/week were 1.12(1.05−1.21),1.09(0.99−1.18),1.20(1.09−1.33),1.29(1.17−1.43)in females and 1.05(0.98−1.13),0.95(0.87−1.05),1.21(1.08−1.37),0.97(0.85−1.09)in males,respectively.The adjusted means of non-HDL-C among the five DoFA status were 3.68 mmol/L,3.73 mmol/L,3.74 mmol/L,3.82 mmol/L,3.84 mmol/L for females and 3.54 mmol/L,3.58 mmol/L,3.51 mmol/L,3.69 mmol/L,3.54 mmol/L for males,respectively.CONCLUSIONS The results of this study have identified a risk association pattern between DoFA status and non-HDL-C levels in females but not in males.Further research is needed to confirm these findings.
文摘Hypertension has been increasingly cited mortality cause in developing countries including Bangladesh,[1–4]and generally associated with coronary artery disease,stroke,heart failure,atrial fibrillation,peripheral vascular disease,vision loss and chronic kidney disease.
文摘Background The WHO has classified depression as a disease of public concern.Police officers are a particular subpopulation group that is at an increased risk for mental health problems.This study examined the prevalence of depression,suicidality and associated risk factors among police officers in urban Tanzania.Aims The aim of this study was to examine the prevalence of depression,suicidality and associated risk factors among police officers in Tanzania.Methods A cross-sectional study was conducted between April 2019 and October 2020 among 550 participants in Dar es Salaam recruited using a multistage cluster sampling technique.The Patient Health Questionnaire-9 was used to screen for depression and suicidality.The Interpersonal Support Evaluation List-12 tool was used to measure perceived social support.Descriptive statistics were summarised using frequencies and percentages.Bivariate and multivariate analyses were used to establish associations between predictors of interest,depression and suicidality.Results There were 497 participants in the study.Of these,76.6%(376 of 491)were men,and the median(IQR)age was 37.0(17)years.Around 19.8%(96 of 486)of the police officers screened positive for depression and 15.4%(75 of 413)for suicidality.A significant proportion was either moderately(29 of 96,30.2%)or severely depressed(8 of 75,10.7%).Of those who experienced suicidal thoughts,10.7%(8 of 75)reported having daily suicidal thoughts.Perceiving low social support was associated with an increased risk of reporting depression(adjusted OR(aOR):28.04,95%CI:8.42 to 93.37,p<0.001)and suicidality(aOR:10.85,95%CI:3.56 to 33.08,p<0.001)as compared with those with high perceived social support.Conclusion The magnitude of depression and suicidality among police officers in urban Tanzania is alarmingly high.The study findings indicate the need for routine screening for depression and suicidality among police officers and design appropriate mental health responsive services in this population.
文摘We demonstrate that the combined use of differential scanning calorimetry(DSC)and cross-sectional transmission electron microscopy(XTEM)is a powerful technique in the quantitative investigation of the nucleation and growth of metastable and equilibrium phases during thin-film interdiffusion reactions.The Various approaches and advantages of the DSC/XTEM technique in obtaining a variety of kinetic and thermodynamic data are discussed.Explosive reactions,as opposed to conventionally controlled reactions,may occur in thin films where the multilayer geometry is used.
基金Supported by the National Natural Science Fund Aided Project (60473128)
文摘To provide practical and surgical anatomy for the imaging diagnosis and surgical treatment of the disease of the caudate lobe of the liver. Methods： Based on Chinese Visible Human 1-5 data sets and assisted by 3D visualization and reconstruction, the 3D models of the upper abdomen or the liver were reconstructed and the cross-sectional images were converted to the coronal and sagittal images. The anatomy of the caudate lobe of the liver on the coronal and sagittal planes was investigated on serial planes of the upper abdomen. Results： The caudate lobe was bordered on the left by the fissura ligamenti venosi, posteriorly by the IVC, superiorly by the hepatic veins and inferiorly by the hepatic hilum. Its right and ventral borders might be obscure, with only relative borders existent. The right wall of the IVC was a good landmark to judge the relative realm of paracaval portion, and the relative ventral plane might exist between the hepatic hilum and entrance of hepatic veins. The caudate lobe could be divided into two principal regions： the left Spiegel lobe and the right paracaval portion. The caudate process, and the right rear process occurring in some individuals belonged to the right paracaval portion. The caudate lobe was blood supplied by the portal vein, which directly drained into the IVC. Conclusion： There are not definite borders for the right part of the caudate lobe, and most of the knowledge on it is based on the cast study, which may not suit for the clinical diagnosis and practice. The coronal and sagittal sections can better show the anatomic relationships between the caudate lobe, the other parts of the liver and the adjacent structures. The 3D digital visualization is an accurate and convenient study method for clinical anatomy.
基金Shanghai Clinical Research Center for Mental Health(19MC1911100)Program of Science and Technology Innovation Plan in Shanghai(18411961200)+4 种基金Shanghai Intelligent Engineering Technology Research Center for Addiction and Rehabilitation(19DZ2255200)the National Nature Science Foundation(U1502228,81771436,81871045)Shanghai Key Laboratory of Psychotic Disorders(13DZ2260500)Program of Shanghai Science and Technology Committee(19411969200)Shanghai Mental Health Center Clinical Research Center Project(CRC2017YB04).
文摘Background In recent years,energy drinks(EDs)have been widely used among young people around the world.The extensive use of EDs also affects the sleep and exercise of adolescents.Aims This study aimed to investigate the consumption of EDs,the knowledge,attitude towards EDs and associated factors of EDs consumption among adolescents in Shanghai,China.Methods A total of 4608 adolescents completed a self-administered questionnaire assessing EDs use history,knowledge and attitude towards EDs.Adolescent Self-rating Life Events Checklist(ASLEC)was used to assess their life events.All participants were divided into two groups based on whether they used them or not.t-test andχ^(2)test were used to compare the differences between the two groups,and binary logistic regression analysis was used to investigate the related factors for EDs consumption.Results 70.5%of the participants reported having ever used EDs.The main avenues to getting information on EDs were from advertisements.67.56%of them believed that EDs had adverse effects on health.22.09%of the participants and 31.55%of their parents took a negative attitude towards EDs.Compared with the non-consumption group,participants in the consumption group were likely to be male,with older age,identified EDs more correctly and did not believe EDs had adverse effects,with more positive attitude and higher ASLEC score.Logistic regression results showed that gender,age,attitude of parents and themselves,knowledge of EDs and ASLEC score significantly predicted EDs consumption.Conclusion EDs consumption was popular among adolescents in Shanghai,and the tailored intervention programmes need to be developed based on the characteristics of adolescents.
文摘During the later period of construction of Tianshengqiao concrete faced rockfill dam(CFRD), cracks appeared in the upstream fill slope. The main reason was the nonuniform deformation. The treatment methods were: for cracks with opening less than 1 cm, the cracked slope was compacted with added effort to eliminate cracks; for cracks with opening greater than 1 cm , crack grouting was carried out . The practice demonstrated the treatment was successful. Careful analysis of the relation between sectionalized filling and crack emergence is of significance in guiding the construction design and drawing out filling plan for a high CFRD.
基金Foundation item： Supported by the National Natural Science Foundation of China（ll071005） Supported by the Natural Science Foundation of Anhui Province Education Department（KJ2008A05zC）
文摘In the present paper, the authors study totally real 2-harmonic submanifolds in a quasi constant holomorphic sectional curvature space and obtain a Simons＇ type inte- gral inequality of compact submanifoids as well as some pinching theorems on＇the second fundamental form.
基金supported by the National Natural Science Foundation of China(Nos.12265006,12375129,U1867212)the Innovation Project of Guangxi Graduate Education(No.YCSWYCSW2022176)the Guangxi Natural Science Foundation(2017GXNSFGA198001).
文摘Based on the Skyrme energy density functional and reaction Q-value,this study proposed an effective nucleus-nucleus poten-tial for describing the capture barrier in heavy-ion fusion processes.The 443 extracted barrier heights were well reproduced with a root-mean-square(RMS)error of 1.53 MeV,and the RMS deviations with respect to 144 time-dependent Hartree-Fock capture barrier heights were only 1.05 MeV.Coupled with the Siwek-Wilczyński formula,wherein three parameters were determined by the proposed effective potentials,the measured capture cross sections at energies around the barriers were reasonably well reproduced for several fusion reactions induced by nearly spherical nuclei as well as by nuclei with large deformations,such as^(154)Sm and^(238)U.The shallow capture pockets and small values of the average barrier radii resulted in the reduction of the capture cross sections for 52,54Cr-and 64 Ni-induced reactions,which were related to the synthesis of new super-heavy nuclei.
基金supported in part by the National Natural Science Foundation of China(Nos.12105327 and 11775108)the Hunan Provincial Innovation Foundation For Postgraduate(No.QL20220210)the Advanced Energy Science and Technology Guangdong Laboratory.
文摘Inelastic collisions are the dominant cause of energy loss in radiotherapy.In the energy range around the Bragg peak,single ionization(SI)and single-electron capture(SC)are the primary inelastic collisions that lead to energy loss.This study employs the classical trajectory Monte Carlo method to study the SI and SC processes of H_(2)O molecules using He^(2+) and C^(6+) projectiles in the energy range of 10 keV/u to 10 MeV/u.The total cross sections,single differential cross sections,impact parameter dependence of SI and SC,and fragmentation cross sections were investigated.Results illustrate that the cross section for SI is the highest when the projectile energy is close to the Bragg peak energy.When the projectile energy is below the Bragg peak energy,the ionized electrons in the forward direction dominate,and the removal of electrons can be associated with large impact parameters.As the projectile energy increases,the emission angle of the electrons gradually transitions from small angles(60°~120°)to large angles(60°~120°),and the removal of electrons is associated with small impact parameters.The energy distributions of the ionized electron are similar when the projectile energy is equal to,below or above the Bragg peak energy.The fragmentation cross sections after SI and SC in the energy range around the Bragg peak were also estimated.
基金supported by the National Key R&D Program of China(No.2022YFA1602401)by the National Natural Science Foundation of China(No.11825504)。
文摘Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early universe.Among these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent reactions.To date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational precision.In this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium abundance.We found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H uncertainty.Currently,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He rate.From the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.
基金the National Key R&D Program of China(No.2023YFA1606401)the National Natural Science Foundation of China(Nos.12135004,11635003 and 11961141004).
文摘Based on the dinuclear system model,the calculated evaporation residue cross sections matched well with the current experimental results.The synthesis of superheavy elements Z=121 was systematically studied through combinations of stable projectiles with Z=21-30 and targets with half-lives exceeding 50 d.The influence of mass asymmetry and isotopic dependence on the projectile and target nuclei was investigated in detail.The reactions^(254)Es(^(46)Ti,3n)^(297)121 and^(252)Es(^(46)Ti,3n)^(295)121 were found to be experimentally feasible for synthesizing superheavy element Z=121,with maximal evaporation residue cross sections of 6.619 and 4.123 fb at 219.9 and 223.9 MeV,respectively.
基金supported by the National Natural Science Foundation of China(Nos.12075027,1232509,11961141004,and 12175152)the National Science Foundation(Nos.Phys-2011890 and Phy-1430152)。
文摘Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle was thought to be the source of the calcium observed in these oldest stars.However,according to the stellar modeling,a nearly tenfold increase in the thermonuclear rate ratio of the break-out ^(19)F(p,γ)^(20) Ne reaction with respect to the competing ^(19)F(p,α)^(16) O back-processing reaction is required to reproduce the observed calcium abundance.We performed a direct measurement of this break-out reaction at the China Jinping underground laboratory.The measurement was performed down to the low-energy limit of E_(c.m.)=186 keV in the center-of-mass frame.The key resonance was observed at 225.2 keV for the first time.At a temperature of approximately 0.1 GK,this new resonance enhanced the thermonuclear ^(19)F(p,γ)^(20) Ne rate by up to a factor of≈7.4,compared with the previously recommended NACRE rate.This is of particular interest to the study of the evolution of the first stars and implies a stronger breakdown in their“warm”CNO cycle through the ^(19)F(p,γ)^(20) Ne reaction than previously envisioned.This break-out resulted in the production of the calcium observed in the oldest stars,enhancing our understanding of the evolution of the first stars.
