Modeling time-dependent mechanical behavior of hard rock considering excavation-induced damage and complex 3D stress states

To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main components:a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state,a quantitative relationship between critical irreversible deformation and complex stress state,and evolution characteristics of strength parameters.The proposed model is implemented in a self-developed numerical code,i.e.CASRock.The reliability of the model is validated through experiments.It is indicated that the time-dependent fracturing potential index(xTFPI)at a given time during the attenuation creep stage shows a negative correlation with the extent of excavationinduced damage.The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress,thereby highlighting the 3D stress-dependent characteristic of the model.Finally,the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed.

Impact of different interaction behavior on epidemic spreading in time-dependent social networks

We investigate the impact of pairwise and group interactions on the spread of epidemics through an activity-driven model based on time-dependent networks.The effects of pairwise/group interaction proportion and pairwise/group interaction intensity are explored by extensive simulation and theoretical analysis.It is demonstrated that altering the group interaction proportion can either hinder or enhance the spread of epidemics,depending on the relative social intensity of group and pairwise interactions.As the group interaction proportion decreases,the impact of reducing group social intensity diminishes.The ratio of group and pairwise social intensity can affect the effect of group interaction proportion on the scale of infection.A weak heterogeneous activity distribution can raise the epidemic threshold,and reduce the scale of infection.These results benefit the design of epidemic control strategy.

A process-oriented approach for identifying potential landslides considering time-dependent behaviors beyond geomorphological features

Geomorphological features are commonly used to identify potential landslides.Nevertheless,overemphasis on these features could lead to misjudgment.This research proposes a process-oriented approach for potential landslide identification that considers time-dependent behaviors.The method integrates comprehensive remote sensing and geological analysis to qualitatively assess slope stability,and employs numerical analysis to quantitatively calculate aging stability.Specifically,a time-dependent stability calculation method for anticlinal slopes is developed and implemented in discrete element software,incorporating time-dependent mechanical and strength reduction calculations.By considering the time-dependent evolution of slopes,this method highlights the importance of both geomorphological features and time-dependent behaviors in landslide identification.This method has been applied to the Jiarishan slope(JRS)on the Qinghai-Tibet Plateau as a case study.The results show that the JRS,despite having landslide geomorphology,is a stable slope,highlighting the risk of misjudgment when relying solely on geomorphological features.This work provides insights into the geomorphological characterization and evolution history of the JRS and offers valuable guidance for studying slopes with similar landslide geomorphology.Furthermore,the process-oriented method incorporating timedependent evolution provides a means to evaluate potential landslides,reducing misjudgment due to excessive reliance on geomorphological features.

Time-dependent Wave Packet Quantum Scattering Study of Reaction S（3p）＋H2→HS＋H on a New ab initio Potential Energy Surface 3A’

A new potential energy surface is presented for the triplet state 3At of the chemical reaction S（3P）＋H2 from a set of accurate ab initio data. The single point energies are computed using highly correlated complete active space self-consistent-field and multi-reference configuration interaction wave functions with a basis set of aug-cc-pV5Z. We have fitted the full set of energy values using many-body expansion method with an Aguado-Paniagua function. Based on the new potential energy surface, we carry out the time-dependent wave packet scattering calculations over the collision energy range of 0.8-2.2 eV. Both the centrifugalsudden approximation and Coriolis Coupling cross sections are obtained. In addition, the total reaction probabilities are calculated for the reactant H2 initially in the vibrational states v=0-3 （j=0）. It is found that initial vibrational excitation enhances the title reaction.

Comparative study of photoionization of atomic hydrogen by solving the one-and three-dimensional time-dependent Schrödinger equations

We develop a numerical scheme for solving the one-dimensional(1D)time-dependent Schrödinger equation(TDSE),and use it to study the strong-field photoionization of the atomic hydrogen.The photoelectron energy spectra obtained for pulses ranging from XUV to near infrared are compared in detail to the spectra calculated with our well-developed code for accurately solving the three-dimensional(3D)TDSE.For XUV pulses,our discussions cover intensities at which the ionization is in the perturbative and nonperturbative regimes.For pulses of 400 nm or longer wavelengths,we distinguish the multiphoton and tunneling regimes.Similarities and discrepancies between the 1D and 3D calculations in each regime are discussed.The observed discrepancies mainly originate from the differences in the transition matrix elements and the energy level structures created in the 1D and 3D calculations.

A GENERALIZED SCALAR AUXILIARY VARIABLE METHOD FOR THE TIME-DEPENDENT GINZBURG-LANDAU EQUATIONS

This paper develops a generalized scalar auxiliary variable(SAV)method for the time-dependent Ginzburg-Landau equations.The backward Euler method is used for discretizing the temporal derivative of the time-dependent Ginzburg-Landau equations.In this method,the system is decoupled and linearized to avoid solving the non-linear equation at each step.The theoretical analysis proves that the generalized SAV method can preserve the maximum bound principle and energy stability,and this is confirmed by the numerical result,and also shows that the numerical algorithm is stable.

Exploring the Path of Shantytown Renewal Based on the Theory of Environment-behavior Studies: A Case Study of the Northwest Area of Saihantala in Baotou City

The application of environment-behavior studies plays an important role in studying the renewal of shantytowns.One of the most humane ways of renewal is designing and constructing the necessary urban spatial environment from the perspective of human daily behavior.Most of the shantytown renovation projects currently carried out in China are mainly focused on demolition and reconstruction,which not only incurs high costs but also damages the original social structure and economic model.During the process of shantytown renewal,it should improve the urban landscape,living environment,and life quality of residents,and ensure the daily life of shantytown residents without increasing their economic burden,and preserve the traces of urban development.In order to achieve this goal,it should explore the renewal strategies of shantytowns from the perspective of environment-behavior studies through behavior maps,on-site research,and literature review.Updating and design from a human perspective often achieve faster and better development;the renewal of shantytowns should be a bottom-up approach and start from a grassroots perspective,completing the renovation design through the composition of the population and behavioral patterns.

A microscopic approach to brittle creep and time-dependent fracturing of rocks based on stress corrosion model

A brittle creep and time-dependent fracturing process model of rock is established by incorporating the stress corrosion model into discrete element method to analyze the creep behavior and microcrack evolution in brittle rocks at a micro-scale level.Experimental validation of the model is performed,followed by numerical simu-lations to investigate the creep properties and microcrack evolution in rocks under single-stage loading,multi-stage loading,and confining pressure,at various constant stress levels.The results demonstrate that as the stress level increases in single-stage creep simulations,the time-to-failure progressively decreases.The growth of microcracks during uniaxial creep occurs in three stages,with tensile microcracks being predominant and the spatial distribution of microcracks becoming more dispersed at higher stress levels.In multi-stage loadingunloading simulations,microcracks continue to form during the unloading stage,indicating cumulative damage resulting from increased axial stress.Additionally,the creep behaviour of rocks under confining pressure is not solely determined by the magnitude of the confining pressure,but is also influenced by the magnitude of the axial stress.The findings contribute to a better understanding of rock deformation and failure processes under different loading conditions,and they can be valuable for applications in rock mechanics and rock engineering.

Upcrossing-based time-dependent resilience of aging structures

The time-dependent resilience of an in-service aging structure provides quantitative measure of the structural ability to prepare for,adapt to,withstand and recover from disruptive events.Resilience models have been proposed in the literature to evaluate the resilience of aging structures subjected to discrete load processes,which are,however,not applicable to handle resilience problems considering continuous load processes.In this paper,a new method is developed to evaluate the time-dependent resilience of aging structures subjected to a continuous load process.The proposed method serves as the complement of the existing resilience models addressing discrete load processes,and takes into account the aging effects of the structural resistance/capacity and the nonstationarity in loads as a result of climate change.A structure suffers from a damage state upon the occurrence of an upcrossing of the load effect with respect to the resistance/capacity,leading to the reduction of the performance function,followed by a recovery process that restores the performance.The proposed method enables the time-dependent resilience to be evaluated via a closed form solution.It is also revealed that,the proposed resilience model takes an extended form of the existing formula for upcrossing-based time-dependent reliability,thus establishing a unified framework for the two quantities.The applicability of the proposed method is demonstrated through examining the time-dependent resilience of a residential building subjected to wind load.The effects of key factors on resilience,including the nonstationarity and correlation structure of the load process,as well as the resistance/capacity deterioration scenario,are investigated through an example.In particular,the structural resilience would be overestimated if ignoring the potential impacts of climate change,which is a relatively non-conservative evaluation.

Thermomechanical Dynamics (TMD) and Bifurcation-Integration Solutions in Nonlinear Differential Equations with Time-Dependent Coefficients

The new independent solutions of the nonlinear differential equation with time-dependent coefficients (NDE-TC) are discussed, for the first time, by employing experimental device called a drinking bird whose simple back-and-forth motion develops into water drinking motion. The solution to a drinking bird equation of motion manifests itself the transition from thermodynamic equilibrium to nonequilibrium irreversible states. The independent solution signifying a nonequilibrium thermal state seems to be constructed as if two independent bifurcation solutions are synthesized, and so, the solution is tentatively termed as the bifurcation-integration solution. The bifurcation-integration solution expresses the transition from mechanical and thermodynamic equilibrium to a nonequilibrium irreversible state, which is explicitly shown by the nonlinear differential equation with time-dependent coefficients (NDE-TC). The analysis established a new theoretical approach to nonequilibrium irreversible states, thermomechanical dynamics (TMD). The TMD method enables one to obtain thermodynamically consistent and time-dependent progresses of thermodynamic quantities, by employing the bifurcation-integration solutions of NDE-TC. We hope that the basic properties of bifurcation-integration solutions will be studied and investigated further in mathematics, physics, chemistry and nonlinear sciences in general.

Prevalence of Helicobacter pylori infection in Chinese military personnel:A cross-sectional,multicenter-based study

BACKGROUND Helicobacter pylori(H.pylori)infection is a prevalent disease encountered in military internal medicine and recognized as the main cause of dyspepsia,gastritis,and peptic ulcer,which are common diseases in military personnel.Current guidelines in China state all patients with evidence of active infection with H.pylori are offered treatment.However,the prevalence of H.pylori infection and its regional distribution in the military population remain unclear,which hinders effective prevention and treatment strategies.Understanding the prevalence of H.pylori infection in the military population will aid in the development of customized strategies to better manage this infectious disease.AIM To investigate the prevalence of H.pylori infection in the Chinese military population in different geographic areas.METHODS This multicenter,retrospective study included 22421 individuals from five tertiary hospitals located in north,east,southwest,and northwest cities of China.H.pylori infection was identified using the urea breath test,which had been performed between January 2020 and December 2021.RESULTS Of the 22421 military service members,7416(33.1%)were urea breath test-positive.The highest prevalence of H.pylori was in the 30-39 years age group for military personnel,with an infection rate of 34.9%.The majority of infected subjects were younger than 40-years-old,accounting for 70.4%of the infected population.The individuals serviced in Lanzhou and Chengdu showed a higher infection prevalence than those in Beijing,Nanjing,and Guangzhou,with prevalence rates of 44.3%,37.9%,29.0%,31.1%,and 32.3%,respectively.CONCLUSION H.pylori infection remains a common infectious disease among military personnel in China and has a relatively high prevalence rate in northwest China.

Experimental study on time-dependent stress and strain of in-plane shear(ModeⅡ) fracture process of rock

Shear-box test with strain measurement was used to study time-dependent stress and strain of in-plane shear(Mode Ⅱ) fracture process of rock and to reveal the mechanism of Mode Ⅱ fracture.Numerical results show that the maximum shear stress τmax at the crack tip is much larger than the maximum tensile stress σ1 and the ratio of τmax/σ1 is about 5,which favors Mode Ⅱ fracture of rock.Test results indicate that the strain-time curve comprises three stages:the linear deformation stage,the micro-cracking stage and the macroscopic crack propagation.The strain in the direction of the original notch plane is negative,due to restraining effect of compressive loading applied to the original notch plane.Both σ1 and τmax are increased as the load increases,but the slope of τmax is larger than that of σ1 and the value of τmax is always larger than that of σ1.Therefore,τmax reaches its limited value at peak load before σ1 and results in Mode Ⅱ fracture of rock.Shear-box(i.e.compression-shear) test becomes a potential standard method for achieving the true Mode Ⅱ fracture and determining Mode Ⅱ fracture toughness of rock.

Time-dependent density functional theoretical studies on the photo-induced dynamics of an HCI molecule encapsulated in C60 under femtosecond laser pulses

By using first-principles simulations based on time-dependent density functional theory, the chemical reaction of an HCl molecule encapsulated in C60 induced by femtosecond laser pulses is observed. The H atom starts to leave the Cl atom and is reflected by the C60 wall. The coherent nuclear dynamic behaviors of bond breakage and recombination of the HCl molecule occurring in both polarized parallel and perpendicular to the H-Cl bond axis are investigated. The radial oscillation is also found in the two polarization directions of the laser pulse. The relaxation time of the H-Cl bond lengths in transverse polarization is slow in comparison with that in longitudinal polarization. Those results are important for studying the dynamics of the chemical bond at an atomic level.

Theoretical Study on the Optical Properties for 2,7- and 3,6-Linked Carbazole Trimers by Time-dependent Density Functional Theory

Electronic properties, such as HOMO and LUMO energies, band gaps, ionization potential （IP） and electron affinity （EA） of 2,7- and 3,6-1inked carbazole trimers, two conjugated oligomcrs with different linkages of carbazole, were studicd by the density functional theory with Becke-Lee-Young-Parr composite exchange correlation functional （B3LYP）. The absorption spectra of these compounds were also investigated by time-dependent density functional theory （TD-DFT） with 6-3 IG＊ basis set. The calculated results indicated that the HOMO and LUMO of the 2,7- and 3,6-1inked carbazole trimers are both slightly destabilized on going from methyl substitution to sec-butyl substitution. Both IP and EA exhibit their good hole-transporting but poor electronaccepting ability. The presence of alkyl groups on the nitrogen atoms does not affect the intra-chain electronic delocalization along the molecular frame. Thus no significant effect on the band gap and absorption spectra of compounds has been found.

Cohort study on the treatment of BRAF V600E mutant metastatic colorectal cancer with integrated Chinese and western medicine

BACKGROUND Patients with BRAF V600E mutant metastatic colorectal cancer(mCRC)have a low incidence rate,poor biological activity,suboptimal response to conventional treatments,and a poor prognosis.In the previous cohort study on mCRC conducted by our team,it was observed that integrated Chinese and Western medicine treatment could significantly prolong the overall survival(OS)of patients with colorectal cancer.Therefore,we further explored the survival benefits in the population with BRAF V600E mutant mCRC.AIM To evaluate the efficacy of integrated Chinese and Western medicine in the treatment of BRAF V600E mutant metastatic colorectal cancer.METHODS A cohort study was conducted on patients with BRAF V600E mutant metastatic colorectal cancer admitted to Xiyuan Hospital of China Academy of Chinese Medical Sciences and Traditional Chinese Medicine Hospital of Xinjiang Uygur Autonomous Region from January 2016 to December 2022.The patients were divided into two cohorts.RESULTS A total of 34 cases were included,with 23 in Chinese-Western medicine cohort(cohort A)and 11 in Western medicine cohort(cohort B).The median overall survival was 19.9 months in cohort A and 14.2 months in cohort B,with a statistically significant difference(P=0.038,hazard ratio=0.46).The 1-3-year survival rates were 95.65%(22/23),39.13%(9/23),and 26.09%(6/23)in cohort A,and 63.64%(7/11),18.18%(2/11),and 9.09%(1/11)in cohort B,respectively.Subgroup analysis showed statistically significant differences in median OS between the two cohorts in the right colon,liver metastasis,chemotherapy,and first-line treatment subgroups(P<0.05).CONCLUSION Integrated Chinese and Western medicine can prolong the survival and reduce the risk of death in patients with BRAF V600E mutant metastatic colorectal cancer,with more pronounced benefits observed in patients with right colon involvement,liver metastasis,combined chemotherapy,and first-line treatment.

Perspectives of high-risk pregnant women on home care program in high-risk pregnancies: A multicenter, qualitative study

Objective:To explore the perspectives of high-risk pregnant women regarding the home care program for high-risk pregnancies.Methods:This qualitative study was conducted in a university hospital and 5 comprehensive health centers in Ahvaz,Iran,from February 2023 to July 2023.The sampling method used was purposive sampling considering the maximum possible diversity,which continued until data saturation.11 in-depth and semistructured interviews were conducted with high-risk pregnant women.Data were simultaneously analysed using Graneheim and Lundman content analysis by MAXQDA version 20 software.Results:Data analysis extracted 3 themes,12 categories,and 26 subcategories.The themes and categories were“high-risk pregnancy and related issues(pursuing treatment and paying attention to the high-risk situation by pregnant women,psychological aspect of high-risk pregnancy on pregnant women and caregivers,emotional and physical aspects of high-risk pregnancy,the consequences of high-risk pregnancy on the people around them and empowerment of high-risk pregnant women)”,“support dimension(family and community support for high-risk pregnant women)”,and“framework of program(acculturalization,means and equipment,security,manpower and the necessary arrangements for the home care)”.Conclusions:High-risk pregnancy affects various aspects of the lives of high-risk pregnant women and their families.Creating the necessary conditions for providing care at home plays a vital role in supporting high-risk pregnant women and removing related obstacles to receiving prenatal care in person.It will be especially beneficial for high-risk pregnant women in low-income areas.

Decreased desire to have children: A qualitative study

Objective:To explain barriers to childbearing among working women from the perspective of working women and midwives.Methods:In this study,a qualitative study of content analysis method was employed.The study was conducted from December 2021 to July 2022.The population consisted of working women and midwives.Data collection was conducted using semi-structured interviews and continued until data saturation was achieved.Through purposeful sampling,10 women and 11 midwives were selected as the sample.The data were analyzed by Graneheim and Lundman content analysis approach.For more rigorous,Nvivo 14 software was also used for data management,analysis,coding and organization of data.Results:This study included 21 women(10 women employees and 11 midwives)aged 25-43 years(for women employees)and 27-56 years(for midwives)with 1 to 34 years of job experience.In examination of participant’views about the barriers to childbearing,1124 codes were identified,of which we managed to extract six subthemes and two themes.Two themes emerged:“lack of social support and lack of family support”.Subthemes of“lack of social support”were“inadequate leave,long distance from workplace,and insufficient wages”.Subthemes of“lack of family support”were“lack of spouse support,lack of spouse's family support,and lack of their family support”.Conclusions:Different socioeconomic factors influence childbearing tendency in working women.Social and family supports play an important role in this regard.It is important to take these factors into account at the time of policymaking in the field of midwifery.

Outcomes of bile duct cannulation using a novel contrast-enhanced catheter: A single-center, retrospective cohort study

BACKGROUND Endoscopic retrograde cholangiopancreatography is a challenging procedure involving bile duct cannulation.Despite the development of several cannulation devices,none have effectively facilitated the procedure.AIM To evaluate the efficacy of a recently developed catheter for bile duct cannulation.METHODS We retrospectively examined 342 patients who underwent initial cholangiopan-creatography.We compared the success rate of bile duct cannulation and the incidence of complications between the groups using existing and novel catheters.RESULTS The overall success rates of bile duct cannulation were 98.3%and 99.1%in the existing and novel catheter groups,respectively(P=0.47).The bile duct cannulation rate using the standard technique was 73.0%and 82.1%in the existing and novel catheter groups,respectively(P=0.042).Furthermore,when catheterization was performed by expert physicians,the bile duct cannulation rate was significantly higher in the novel catheter group(81.3%)than in the existing catheter group(65.2%)(P=0.017).The incidence of difficult cannulation was also significantly lower in the novel catheter group(17.4%)than in the existing catheter group(33.0%)(P=0.019).CONCLUSION The novel catheter improved the bile duct cannulation rate using the standard technique and reduced the frequency of difficult cannulation cases,valuable tool in endoscopic retrograde cholangiopancreatography procedures performed by experts.

Bibliometric analysis on the top one hundred cited studies on gastrointestinal endoscopy

BACKGROUND Gastrointestinal endoscopy has been widely used in the diagnosis and treatment of gastrointestinal diseases.A great many of studies on gastrointestinal endoscopy have been done.AIM To analyze the characteristics of top 100 cited articles on gastrointestinal endoscopy.METHODS A bibliometric analysis was conducted.The publications and their features were extracted from the Web of Science Core Collection,Science Citation Index-Expanded database.Excel,Web of Science database and SPSS software were used to perform the statistical description and analysis.VOSviewer software and Map-Chart were responsible for the visualizations.RESULTS The top 100 cited articles were published between 1976 and 2022.The guidelines(52%)and clinical trials(37%)are the main article types,and average publication year of the guidelines is much later than that of the clinical trials(2015 vs 1998).Among the clinical trials,diagnostic study(27.0%),cohort study(21.6%),case series(13.5%)and cross-sectional study(10.8%)account for a large proportion.Average citations of different study types and designs of the enrolled studies are of no significant differences.Most of the 100 articles were published by European authors and recorded by the endoscopic journals(65%).Top journals in medicine,such as the Lancet,New England Journal of Medicine and JAMA,also reported studies in this field.The hot spots of involved diseases include neoplasm or cancer-related diseases,inflammatory diseases,obstructive diseases,gastrointestinal hemorrhage and ulcer.Endoscopic surgery,endoscopic therapy and stent placement are frequently studied.CONCLUSION Our research contributes to delineating the field and identifying the characteristics of the most highly cited articles.It is noteworthy that there is a significantly smaller number of clinical trials included compared to guidelines,indicating potential areas for future high-quality clinical trials.

Metastatic lymph node distribution and pathology correlations in upper and lower gastric cancer patients:A multicenter retrospective study

BACKGROUND Gastric cancer(GC)poses a significant threat to public health.However,the clinicopathological features and tumor biological behaviors vary among the GC patients,leading to individual variations in lymph node metastasis.Consequently,the stratification of lymph node dissection according to the specific type,particularly upper GC,has emerged as a prominent area of research.AIM To investigate the distribution of metastatic lymph nodes in patients with upper and lower GC and to analyze the differences in related pathological elements and prognosis.METHODS Differential analysis between upper and lower GC patients with various clinicopathological factors was performed using the chi-square test and rank-sum regression models were used to analyze risk factors affecting patient prognosis.The Kaplan-Meier method was used to construct survival curves associated with prognostic risk factors for GC.RESULTS Significant differences were observed between the two GC populations regarding tumor diameter,histological grade,pT stage,pN stage,tumor-node-metastasis(pTNM)stage,vascular invasion,and adjuvant chemotherapy usage(all P<0.05).Lymph node metastasis rates were highest for Siewert type II patients in groups Nos.1,3,2 and 7;for Siewert type III patients in groups Nos.3,1,2 and 7;and for other/unclassified patients in groups Nos.1,3,7,2.In the lower GC samples,the sequences were Nos.3,6,7,4.Pathological type,pT stage,pTNM stage,and positive vascular invasion were independent risk factors for development of lymph node metastasis.Age,pathological type,pT stage,pN stage,pTNM stage,vascular invasion,and absence of adjuvant chemotherapy were identified as independent prognostic factors.CONCLUSION Upper GC showed a significantly higher malignancy grade and different lymph node metastasis pattern than lower GC.