The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concr...The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.展开更多
Objective We aimed to understand the willingness and barriers to the acceptance of tuberculosis(TB)preventive treatment(TPT)among people with latent TB infection(LTBI)in China.Methods A multicenter cross-sectional stu...Objective We aimed to understand the willingness and barriers to the acceptance of tuberculosis(TB)preventive treatment(TPT)among people with latent TB infection(LTBI)in China.Methods A multicenter cross-sectional study was conducted from May 18,2023 to December 31,2023 across 10 counties in China.According to a national technical guide,we included healthcare workers,students,teachers,and others occupations aged 15-65 years as our research participants.Results Overall,17.0%(183/1,077)of participants accepted TPT.There were statistically significant differences in the acceptance rate of TPT among different sexes,ages,educational levels,and occupations(P<0.05).The main barriers to TPT acceptance were misconceptions that it had uncertain effects on prevention(57.8%,517/894),and concerns about side effects(32.7%,292/894).Conclusion An enhanced and comprehensive understanding of LTBI and TPT among people with LTBI is vital to further expand TPT in China.Moreover,targeted policies need to be developed to address barriers faced by different groups of people.展开更多
Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately ...Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately threatening the stability of underground structures. In order to explore the mechanical properties of rocks under H-M coupling, the corresponding damage constitutive(D-C) model has become the focus of attention. Considering the inadequacy of the current research on rock strength parameters,energy evolution characteristics and D-C model under H-M coupling, the mechanical properties of typical sandstone samples are discussed based on laboratory tests. The results show that the variation of characteristic stresses of sandstone under H-M coupling conforms to the normalized attenuation equation and Mohr-Coulomb(M-C) criterion. The P-W pressure mechanism of sandstone exhibits a dynamic change from softening effect to H-M fracturing effect. The closure stress is mainly provided by cohesive strength, while the initiation stress, damage stress, and peak stress are jointly dominated by cohesive strength and friction strength. In addition, residual stress is attributed to the friction strength formed by the bite of the fracture surface. Subsequently, the energy evolution characteristics of sandstone under H-M coupling were studied, and it was found that P-W pressure weakened the energy storage capacity and energy dissipation capacity of sandstone, and H-M fracturing was an important factor in reducing its energy storage efficiency. Finally, combined with energy dissipation theory and statistical damage theory, two types of D-C models considering P-W pressure are proposed accordingly, and the model parameters can be determined by four methods. The application results indicate that the proposed and modified D-C models have high reliability, and can characterize the mechanical behavior of sandstone under H-M coupling, overcome the inconvenience of existing D-C models due to excessive mechanical parameters,and can be applied to the full-range stress–strain process. The results are conducive to revealing the deformation and damage mechanisms of rocks under H-M coupling, and can provide theoretical guidance for related engineering problems.展开更多
The application of ductile rock bolts has been a crucial method for solving the problems of large deformations,energy absorption and stability control issues in deep rock masses.To study the anchoring mechanism of the...The application of ductile rock bolts has been a crucial method for solving the problems of large deformations,energy absorption and stability control issues in deep rock masses.To study the anchoring mechanism of the key expansive structure,this paper proposes a novel type of bolt—the Ductile-Expansion bolt,and conducts research on anchoring mechanics,energy absorption characteristics,and failure modes of the bolt.In addition,this paper defines the concept of load-volume ratio of metal rock bolts and proves the Ductile-Expansion bolt is capable of better improving the unit volume bearing capacity of the bolt material.Furthermore,laboratory and field tests verify the Ductile-Expansion bolt had better anchoring effect than the traditional rebar bolt,with the expansion structure favorably enhancing the ductility and energy absorption performance of the bolt.Finally,this paper microscopically analyzes the crack propagation and distribution morphology of the bolts by establishing a 3D coupled numerical model based on FDM-DEM.Numerical results illustrate the interface at the variable diameter of the Ductile-Expansion bolt serves as the transition zone between high and low stress levels.The expansion structure can impose radial compression on the medium around the bolt,which can improve the bolt anchorage performance.展开更多
This paper investigates mechanical behaviours of sandstone during post-peak cyclic loading and unloading subjected to hydromechanical coupling effect, confirming the peak and residual strengths reduction laws of sands...This paper investigates mechanical behaviours of sandstone during post-peak cyclic loading and unloading subjected to hydromechanical coupling effect, confirming the peak and residual strengths reduction laws of sandstone with water pressure, and revealing the influence of water pressure on the upper limit stress and deformation characteristics of sandstone during post-peak cyclic loading and unloading.Regarding the rock strength, the experimental study confirms that the peak strength σ_(p) and residual strength σ_(r) decrease as water pressure P increases. Especially, the normalized strength parameters σ_(p)/σ_(pk) and σ_(r)/σ_(re) was negatively and linearly correlated with the P/σ_(3). Moreover, the Hoek-Brown strength criterion can be applied to describe the relationship between effective peak strength and effective confining stress. During post-peak cyclic loading and unloading, both the upper limit stress σ_(p(i)) and crack damage threshold stress σ_(cd(i)) of each cycle tend to decrease with the increasing cycle number. A hysteresis loop exists among the loading and unloading stress–strain curves, indicating the unloading deformation modulus E_(unload) is larger than the loading deformation modulus E_(load). Based on experimental results,a post-peak strength prediction model related to water pressure and plastic shear strain is established.展开更多
In this paper,the hydrogeological characteristics in the southern coalfields of China are first briefly outlined.Then,taking the Meitanba mine as an example,the evolution and modeling of mine water inflow are studied....In this paper,the hydrogeological characteristics in the southern coalfields of China are first briefly outlined.Then,taking the Meitanba mine as an example,the evolution and modeling of mine water inflow are studied.Finally,the hazard characteristics related to mine water and mud inrush are analyzed.The results show that the main mine water sources in the Meitanba mine area are groundwater,surface water and precipitation.The evolution of mine water inflow with time indicates that the water inflow is closely related to the development of karst structures,the amount of water from rainfall infiltration,and the scope of groundwater depression cone.The mine water inflow increases with time due to the increase in mining depth and the expansion of groundwater depression cone.Using the big well method and following the potential superposition principle,a hydrogeological model considering multi-well interactions has been developed to predict the mine water inflow.Based on the monitored data in the Meitanba mine area over a period of nearly 60 years,it is found that with increasing mining depth,the number of water and mud inrush points tended to decrease.However,the average water and mud flow rate per point tended to increase.展开更多
With the introduction of various carbon reduction policies around the world,hydrogen energy,as a kind of clean energy with zero carbon emission,has attracted much attention.The safe and economical transportation of hy...With the introduction of various carbon reduction policies around the world,hydrogen energy,as a kind of clean energy with zero carbon emission,has attracted much attention.The safe and economical transportation of hydrogen is of great significance to the development of hydrogen energy industries.Utilizing natural gas pipelines to transport hydrogen is considered to be an efficient and economical way.However,hydrogen has a higher risk of leakage due to its strong diffusion capacity and lower explosive limit than conventional natural gas.Therefore,it is of great significance to study the leakage and diffusion law of hydrogen-enriched natural gas(HENG)pipelines for the safe transportation of hydrogen energy.In this study,the leakage and diffusion characteristics of urban buried HENG pipelines are investigated numerically,and the dangerous degree of leakage is analyzed based on the time and area when the gas concentration reaches the lower explosive limit.The influences of hydrogen blending ratio(HBR),operating pressure,leakage hole size and direction,as well as soil type on the leakage and diffusion law of HENG are analyzed.Results show that the hydrogen mixing is not the key factor in increasing the degree of risk after gas leakage for urban buried HENG pipelines.When the HBR is 5%,10%,15% and 20%,the corresponding first dangerous time is 1053,1041,1019 and 998 s,respectively.Thiswork is expected to provide a valuable reference for the safe operation and risk prevention of HENG pipelines in the future.展开更多
Objective: To analyze characterization of the rpoBgene mutations of Mycobacterium tuber- culosis isolated from China and to explore the association of specific mutations conferring rifampicin (RIF) resistance with Bei...Objective: To analyze characterization of the rpoBgene mutations of Mycobacterium tuber- culosis isolated from China and to explore the association of specific mutations conferring rifampicin (RIF) resistance with Beijing genotype strains. Methods: Genotypic analysis of 3479M. tuberculosis isolatesincluding 402 RIF-resistantand 3077 RIF-susceptible isolated from the na- tional drug-resistant tuberculosis baseline survey was performed. Results: DNA sequencing analysis of the 81-bp RIF resistance determining region (RRDR) of the ropB gene revealed that 98.01% of RIF-resistant strains showedrpoBgene mutation, isolates with mutations at codon rpoB531, rpoB 526 and rpoB 516 were the most frequently. Analysis of the rpoB gene of 3077 RIF-susceptible strains revealed that 98.96% of the strains had no mutation. The distribution of mutation frequency at differentcritical codons in different regions of China was statistically significant (p = 0.001). There was no significant difference in the occurrence of mutations at critical codons between the rifampicin-resistant Bei-jing and non-Beijing isolates.Conclusion: About 98% of RIF-resistant strains isolated from China carry mutations in RRDR ofrpoB gene.Mutation profiles in RIF-resistantM. tuberculosis clinical isolates are variable depending on the different geographical regionsof China. The results provide valuable information in adopting new molecular methods for diagnosis of TB in China.展开更多
With the rapid development of the individualized demand market,the demand for manufacturing flexibility has increased over time.As a result,a cell manufacturing system suitable for many varieties and small batches has...With the rapid development of the individualized demand market,the demand for manufacturing flexibility has increased over time.As a result,a cell manufacturing system suitable for many varieties and small batches has been produced.With the goal of minimizing the area and logistics handling volume,and considering the arrangement order of facilities and channel constraints,a mathematical model was established,and the problem was solved by improved NSGA-II.After non-dominated sorting,traditional NSGA-II will cross-operate the individuals with the best sorting to generate new individuals.Such a selection strategy is extremely easy to fall into the local optimal solution.The improved NSGA-II is to improve the original selection operation,which is to select the first half of the excellent individuals in the non-dominated sorting into the cross operation,and then select the last sorted ones of the remaining individuals into the cross operation,and combine the best and the worst ones into the cross operation.Finally,an example is given to simulate and improve the solution of NSGA-II and NSGA-II.The simulation results indicate that the improved NSGA-II population shows more obvious diversity,it is easier to jump out of the local optimal solution than NSGA-II,and the satisfactory layout scheme of manufacturing cells is obtained.Therefore,it is more effective to use improved NSGA-II to solve the problem of manufacturing cell layout.展开更多
The authors regret that ‘Houquan Zhang’applies to remove his name and affiliation from the author list because he thought that he didn't make enough great contributions to this paper,just dis-cus:sion about the ...The authors regret that ‘Houquan Zhang’applies to remove his name and affiliation from the author list because he thought that he didn't make enough great contributions to this paper,just dis-cus:sion about the outline for the paper writing and some revision suggestions.The correct author list and affi liations are updated as above.展开更多
To distinguish Mycobacterium tuberculosis from Mycobacterium avium, specific M. tuberculosis antigens had been studied for improving the early differential diagnosis effect of tuberculosis caused by different Mycobact...To distinguish Mycobacterium tuberculosis from Mycobacterium avium, specific M. tuberculosis antigens had been studied for improving the early differential diagnosis effect of tuberculosis caused by different Mycobacterium. The rabbit anti-M. avium sera and anti-M. tuberculosis sera were analyzed for antibody-based reactivity by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-TOF Mass) against M. tuberculosis proteins. The immunoreactive spots, which were attributed to the proteins HspX, GroES and CFP-10, were mostly located at 10 - 60 kDa and PI 4 - 6, subsequently Western blotting result proved that HspX and CFP-10 were specific to M. tuberculosis and ELISA testing result of 30 M. avium positive sera showed that GroES were cross-reactive to M. avium. Lastly, positive and negative tuberculosis reference sera and based on the mechanism of indirect ELISA, the specificity and the sensitivity of the methods targeting the antibodies HspX, GroES or CFP-10 were evaluated at 37% and 26%, 12% and 97%, 81% and 98%, respectively. The combination of these three antibody detection methods allowed to reached a specificity of 42%, and of 39% without taken into account of the method targeting the GroES antibody. Using proteomics approach, we found three M. tuberculosis specific antigens showed good potential in tuberculosis diagnosis, providing basic study for serodiagnosis of tuberculosis.展开更多
This paper addresses the World Tuberculosis(TB)Day 2025 theme,“Yes!We can end TB!Commit,Invest,Deliver”.Through comprehensive analysis of China’s TB epidemic landscape and associated challenges,we align with the“N...This paper addresses the World Tuberculosis(TB)Day 2025 theme,“Yes!We can end TB!Commit,Invest,Deliver”.Through comprehensive analysis of China’s TB epidemic landscape and associated challenges,we align with the“National TB Prevention and Control Plan(2024−2030)”which emphasizes that building Zero-TB communities through the integration of“active case finding”and“TB preventive treatment(TPT)”represents a viable pathway toward ending the TB epidemic.Active case finding serves as a critical intervention for early detection and transmission reduction,while TPT constitutes an essential strategy for decreasing latent TB infection incidence.By facilitating the rapid expansion of Zero-TB communities through governmental commitment,strategic resource allocation,and coordinated implementation,we anticipate achieving the ultimate goal of TB epidemic elimination.展开更多
Background Most high tuberculosis(TB)burden countries are in low-and middle-income regions undergoing rapid urbanization.We aimed to assess the association between urbanization factors and TB incidence in China.Method...Background Most high tuberculosis(TB)burden countries are in low-and middle-income regions undergoing rapid urbanization.We aimed to assess the association between urbanization factors and TB incidence in China.Methods We evaluated urbanization at the county level in China from 2005 to 2019 using a composite index integrating pop-ulation density,gross domestic product(GDP,per capita),hospital beds per 10o0 population,nighttime light(NTL),and normal-ized difference vegetation index(NDVI).The annual incidence rate and number of TB cases were obtained from the national Tuberculosis Information Management System,maintained by the Chinese Center for Disease Control and Prevention.Fixed-effects models were used to examine the association between urbanization factors and TB incidence.A subgroup analysis Was performed by dividing counties into four regions:northeast,eastern,central,and western.Results A total of 1992 counties in China were included in this study.Overall,urbanization scores were associated with reduced TB incidence(β=-0.0114,P<0.001),corresponding to a 1.1%reduction in TB incidence per unit score.Quadratic models presented a U-shaped relationship between urbanization and TB incidence with an inflection point at 52.94 urbanization units.For each indicator of urbanization,population density and the number of hospital beds were positively associated with TB incidence,with incidence rate ratios of 11.384[95%confidence interval(Cl):9.337 to 13.881],and 1.015(95%C/:1.011 to 1.019),respectively,while GDP,NTL,and NDVI exhibited protective effects.Cen-tral China displayed an increase trend that urbanization score was linked to a 1.8%rise in TB incidence.Conclusions Urbanization-related factors,including GDP,NTL and NDVI,were inversely associated with TB incidence.Central China's contrasting results highlighted region-specific challenges.Therefore,governments in developing countries should adopt integrated approaches that promote both economic growth and sustainable development of environment during urbanization to optimize TB control efforts.展开更多
The 2024World Health Organization(WHO)Global Tuberculosis Report underscores progress and persisting challenges in the fight against tuberculosis(TB).1 TB remains a significant global health concern,with a slight stab...The 2024World Health Organization(WHO)Global Tuberculosis Report underscores progress and persisting challenges in the fight against tuberculosis(TB).1 TB remains a significant global health concern,with a slight stabilization in the incidence rate following disruptions caused by the COVID-19 pandemic.However,achieving the goals of the End TB Strategy by 2035 requires more accelerated efforts.2 The report reveals that,while the global rise in TB incidence has slowed,the number of people falling ill with TB continues to rise,highlighted by a global estimate of 10.8 million TB cases in 2023,with 30 high TB burden countries accounting for 87%of the global total TB cases.It is noteworthy that five countries accounted for 56%of the global TB burden,with India contributing the largest share at 26%,followed by Indonesia at 10%,China at 6.8%,the Philippines at 6.8%and Pakistan at 6.3%.Despite a reduction in TB deaths globally(approximately 1.25 million in 2023 compared with 1.32 million in 2022),TB has reclaimed its position as the leading cause of death from a single infectious agent,surpassing COVID-19.TB deaths are primarily due to complications resulting from untreated or poorly managed TB infections.The leading causes of death include the progression of pulmonary TB and TB with HIV/AIDS.Highmortality TB diseases such as tuberculous meningitis,miliary TB and disseminated TB remain critically neglected,receiving insufficient attention and lacking adequate treatment strategies.3–6 Addressing this neglect requires urgent investment in advanced diagnostics,personalized treatments and innovative drug therapies.Expanding healthcare capacity and establishing effective treatment standards are vital to combating these overlooked diseases and reducing mortality,particularly amid rising drug resistance.展开更多
Summary What is already known about this topic?The recurrence of tuberculosis(TB)following successful treatment presents a significant challenge.What is added by this report?Achieving the global End TB Strategy milest...Summary What is already known about this topic?The recurrence of tuberculosis(TB)following successful treatment presents a significant challenge.What is added by this report?Achieving the global End TB Strategy milestones and targets with the current strategies in China is challenging.However,interventions following recovery to prevent recurrence,in conjunction with preventive treatment for latent TB infection(LTBI),will aid in meeting these objectives.展开更多
Background Patients with tuberculosis resistant to isoniazid but susceptible to rifampicin(Hr-Rs TB)remain a neglected demographic,despite a high disease burden and poor outcomes of these patients.The aim of this stud...Background Patients with tuberculosis resistant to isoniazid but susceptible to rifampicin(Hr-Rs TB)remain a neglected demographic,despite a high disease burden and poor outcomes of these patients.The aim of this study was to investigate the characteristics of isoniazid-resistance-related mutations in Mycobacterium tuberculosis and resistance rates to drugs included in WHO-recommended regimens for Hr-Rs patients.Methods Mycobacterium tuberculosis isolates(n=4922)obtained from national tuberculosis drug-resistance surveillance were subjected to whole-genome sequencing to identify Hr-Rs strains.The minimal inhibitory concentrations(MICs)were established for the Hr-Rs strains to determine the isoniazid resistance levels.We also identified drug-resistance-associated mutations for five drugs(fluoroquinolones,ethambutol,pyrazinamide,streptomycin,and amikacin)in the Hr-Rs strains.Results Of the 4922 strains,384(7.8%)were Hr-Rs.The subculture of seven strains failed,so 377(98.2%)strains underwent phenotypic MIC testing.Among the 384 genotypic Hr-Rs strains,242(63.0%)contained the katG Ser315Thr substitution;115(29.9%)contained the-15C>T in the promoter region of the fabG1 gene;and 16(4.2%)contained Ser315Asn in the katG gene.Of the 239 strains with the Ser315Thr substitution,229(95.8%)had MIC≥2µg/mL,and of the 114 strains with the-15C>T mutation,103(90.4%)had 0.25µg/mL≤MIC≤1µg/mL.The genotypic resistance rates were 0.8%(3/384)for pyrazinamide,2.3%(9/384)for ethambutol and fluoroquinolones;39.6%(152/384)of the strains were resistant to streptomycin,but only 0.5%(2/384)of the strains were resistant to amikacin.Conclusion Ser315Thr in katG was the predominant mutation conferring the Hr-Rs phenotype,followed by the fabG1-15C>T mutation.The combination of rifampicin,pyrazinamide,ethambutol,and levofloxacin should be effective in the treatment of patients with Hr-Rs tuberculosis because the resistance rates for these drugs in China are low.展开更多
Summary What is already known about this topic?The coronavirus disease(COVID-19)pandemic could have a damaging impact on access to tuberculosis(TB)diagnosis and treatment.What is added by this report?The overall delay...Summary What is already known about this topic?The coronavirus disease(COVID-19)pandemic could have a damaging impact on access to tuberculosis(TB)diagnosis and treatment.What is added by this report?The overall delay experienced by TB patients during the COVID-19 pandemic has shown a modest decrease in comparison to the period before the pandemic.Notably,higher patient delays were observed among agricultural workers and those identified through passive case-finding methods.Furthermore,the patient delay in eastern regions was shorter compared to western and central regions.展开更多
Introduction:National Notifiable Disease Reporting System(NNDRS)plays an important role in the early detection and control of tuberculosis(TB)in China.This study analyzed the epidemiological characteristics of pulmona...Introduction:National Notifiable Disease Reporting System(NNDRS)plays an important role in the early detection and control of tuberculosis(TB)in China.This study analyzed the epidemiological characteristics of pulmonary tuberculosis(PTB)in Kashgar Prefecture,Xinjiang Uygur Autnomous Region,China from 2011 to 2020 to provide a scientific basis for developing TB control strategies and measures in Kashgar.Methods:The data were collected from the NNDRS,which included the geographical distribution,age,sex,occupation,and pathogenic classification of reported PTB cases in 12 counties/cities of Kashgar Prefecture from 2011 to 2020.Descriptive statistics were used to describe the characteristic of PTB epidemic in Kashgar.Results:There were 189,416 PTB cases reported during 2011–2020,with a mean annual PTB case notification rate(CNR)of 451.29/100,000.A rising trend in the rate of reported PTB between 2011 and 2017(χ2 trend=26.09,P<0.01)and a declining trend between 2018 and 2020(χ2 trend=314.44,P<0.01)were observed.The months with the highest reported number of PTB cases were March to May and November to December.The mean annual rate of reported PTB was 451.88/100,000 for males and 450.67/100,000 for females.In addition,19.76%of patients were bacteriologically-confirmed(Bac+)cases(37,425/189,416),and the mean annual Bac+CNR was 89.17/100,000,rising from 64.76/100,000 in 2011 to 139.12/100,000 in 2020(χ^(2)_(trend)=74.44,P<0.01).Conclusions:The CNR of reported PTB in Kashgar showed a significant declining trend in the past three years.Males,elderly population,winter and spring,and farmers as an occupation were the main factors associated with high incidence of tuberculosis in Kashgar.Targeted prevention and treatment of TB should be strengthened in key groups in this region.展开更多
基金financial support by the National Natural Science Foundation of China(52174101&52408310)Guangdong Basic and Applied Basic Research Foundation(2023A1515011634&2024A1515012528)Guangdong Provincial Department of Science and Technology(2021ZT09G087)for the research.
文摘The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.
基金Public-Benefit Project on Tuberculosis Patient Care Action[09107].
文摘Objective We aimed to understand the willingness and barriers to the acceptance of tuberculosis(TB)preventive treatment(TPT)among people with latent TB infection(LTBI)in China.Methods A multicenter cross-sectional study was conducted from May 18,2023 to December 31,2023 across 10 counties in China.According to a national technical guide,we included healthcare workers,students,teachers,and others occupations aged 15-65 years as our research participants.Results Overall,17.0%(183/1,077)of participants accepted TPT.There were statistically significant differences in the acceptance rate of TPT among different sexes,ages,educational levels,and occupations(P<0.05).The main barriers to TPT acceptance were misconceptions that it had uncertain effects on prevention(57.8%,517/894),and concerns about side effects(32.7%,292/894).Conclusion An enhanced and comprehensive understanding of LTBI and TPT among people with LTBI is vital to further expand TPT in China.Moreover,targeted policies need to be developed to address barriers faced by different groups of people.
基金funding support from the National Natural Science Foundation of China(Nos.52174088 and 42277154)the Independent Innovation Research Fund Graduate Free Exploration Project(No.104972024JYS0007)supported by Wuhan University of Technology.
文摘Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately threatening the stability of underground structures. In order to explore the mechanical properties of rocks under H-M coupling, the corresponding damage constitutive(D-C) model has become the focus of attention. Considering the inadequacy of the current research on rock strength parameters,energy evolution characteristics and D-C model under H-M coupling, the mechanical properties of typical sandstone samples are discussed based on laboratory tests. The results show that the variation of characteristic stresses of sandstone under H-M coupling conforms to the normalized attenuation equation and Mohr-Coulomb(M-C) criterion. The P-W pressure mechanism of sandstone exhibits a dynamic change from softening effect to H-M fracturing effect. The closure stress is mainly provided by cohesive strength, while the initiation stress, damage stress, and peak stress are jointly dominated by cohesive strength and friction strength. In addition, residual stress is attributed to the friction strength formed by the bite of the fracture surface. Subsequently, the energy evolution characteristics of sandstone under H-M coupling were studied, and it was found that P-W pressure weakened the energy storage capacity and energy dissipation capacity of sandstone, and H-M fracturing was an important factor in reducing its energy storage efficiency. Finally, combined with energy dissipation theory and statistical damage theory, two types of D-C models considering P-W pressure are proposed accordingly, and the model parameters can be determined by four methods. The application results indicate that the proposed and modified D-C models have high reliability, and can characterize the mechanical behavior of sandstone under H-M coupling, overcome the inconvenience of existing D-C models due to excessive mechanical parameters,and can be applied to the full-range stress–strain process. The results are conducive to revealing the deformation and damage mechanisms of rocks under H-M coupling, and can provide theoretical guidance for related engineering problems.
基金supported by the National Natural Science Foundation of China(Nos.52174101,52474169,and 42477202)Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515011634 and 2023A1515030243)the Department of Science and Technology of Guangdong Province,China(No.2021ZT09G087).
文摘The application of ductile rock bolts has been a crucial method for solving the problems of large deformations,energy absorption and stability control issues in deep rock masses.To study the anchoring mechanism of the key expansive structure,this paper proposes a novel type of bolt—the Ductile-Expansion bolt,and conducts research on anchoring mechanics,energy absorption characteristics,and failure modes of the bolt.In addition,this paper defines the concept of load-volume ratio of metal rock bolts and proves the Ductile-Expansion bolt is capable of better improving the unit volume bearing capacity of the bolt material.Furthermore,laboratory and field tests verify the Ductile-Expansion bolt had better anchoring effect than the traditional rebar bolt,with the expansion structure favorably enhancing the ductility and energy absorption performance of the bolt.Finally,this paper microscopically analyzes the crack propagation and distribution morphology of the bolts by establishing a 3D coupled numerical model based on FDM-DEM.Numerical results illustrate the interface at the variable diameter of the Ductile-Expansion bolt serves as the transition zone between high and low stress levels.The expansion structure can impose radial compression on the medium around the bolt,which can improve the bolt anchorage performance.
基金supported by the National Natural Science Foundation of China(Nos.52274118 and 52274145)the Construction Project of Chenzhou National Sustainable Development Agenda Innovation Demonstration Zone(No.2021sfQ18).
文摘This paper investigates mechanical behaviours of sandstone during post-peak cyclic loading and unloading subjected to hydromechanical coupling effect, confirming the peak and residual strengths reduction laws of sandstone with water pressure, and revealing the influence of water pressure on the upper limit stress and deformation characteristics of sandstone during post-peak cyclic loading and unloading.Regarding the rock strength, the experimental study confirms that the peak strength σ_(p) and residual strength σ_(r) decrease as water pressure P increases. Especially, the normalized strength parameters σ_(p)/σ_(pk) and σ_(r)/σ_(re) was negatively and linearly correlated with the P/σ_(3). Moreover, the Hoek-Brown strength criterion can be applied to describe the relationship between effective peak strength and effective confining stress. During post-peak cyclic loading and unloading, both the upper limit stress σ_(p(i)) and crack damage threshold stress σ_(cd(i)) of each cycle tend to decrease with the increasing cycle number. A hysteresis loop exists among the loading and unloading stress–strain curves, indicating the unloading deformation modulus E_(unload) is larger than the loading deformation modulus E_(load). Based on experimental results,a post-peak strength prediction model related to water pressure and plastic shear strain is established.
基金This research is supported by the National Natural Science Foundation of China(Nos.51774131,51874133)Construction Project of Chenzhou National Sustainable Development Agenda Innovation Demonstration Zone(2021sfQ18).
文摘In this paper,the hydrogeological characteristics in the southern coalfields of China are first briefly outlined.Then,taking the Meitanba mine as an example,the evolution and modeling of mine water inflow are studied.Finally,the hazard characteristics related to mine water and mud inrush are analyzed.The results show that the main mine water sources in the Meitanba mine area are groundwater,surface water and precipitation.The evolution of mine water inflow with time indicates that the water inflow is closely related to the development of karst structures,the amount of water from rainfall infiltration,and the scope of groundwater depression cone.The mine water inflow increases with time due to the increase in mining depth and the expansion of groundwater depression cone.Using the big well method and following the potential superposition principle,a hydrogeological model considering multi-well interactions has been developed to predict the mine water inflow.Based on the monitored data in the Meitanba mine area over a period of nearly 60 years,it is found that with increasing mining depth,the number of water and mud inrush points tended to decrease.However,the average water and mud flow rate per point tended to increase.
基金supported by the National Key R&D Program of China (No.2021YFB4001602),the National Natural Science Foundation of China (No.51904031)the Award Cultivation Foundation from Beijing Institute of Petrochemical Technology (No.BIPTACF-002).
文摘With the introduction of various carbon reduction policies around the world,hydrogen energy,as a kind of clean energy with zero carbon emission,has attracted much attention.The safe and economical transportation of hydrogen is of great significance to the development of hydrogen energy industries.Utilizing natural gas pipelines to transport hydrogen is considered to be an efficient and economical way.However,hydrogen has a higher risk of leakage due to its strong diffusion capacity and lower explosive limit than conventional natural gas.Therefore,it is of great significance to study the leakage and diffusion law of hydrogen-enriched natural gas(HENG)pipelines for the safe transportation of hydrogen energy.In this study,the leakage and diffusion characteristics of urban buried HENG pipelines are investigated numerically,and the dangerous degree of leakage is analyzed based on the time and area when the gas concentration reaches the lower explosive limit.The influences of hydrogen blending ratio(HBR),operating pressure,leakage hole size and direction,as well as soil type on the leakage and diffusion law of HENG are analyzed.Results show that the hydrogen mixing is not the key factor in increasing the degree of risk after gas leakage for urban buried HENG pipelines.When the HBR is 5%,10%,15% and 20%,the corresponding first dangerous time is 1053,1041,1019 and 998 s,respectively.Thiswork is expected to provide a valuable reference for the safe operation and risk prevention of HENG pipelines in the future.
文摘Objective: To analyze characterization of the rpoBgene mutations of Mycobacterium tuber- culosis isolated from China and to explore the association of specific mutations conferring rifampicin (RIF) resistance with Beijing genotype strains. Methods: Genotypic analysis of 3479M. tuberculosis isolatesincluding 402 RIF-resistantand 3077 RIF-susceptible isolated from the na- tional drug-resistant tuberculosis baseline survey was performed. Results: DNA sequencing analysis of the 81-bp RIF resistance determining region (RRDR) of the ropB gene revealed that 98.01% of RIF-resistant strains showedrpoBgene mutation, isolates with mutations at codon rpoB531, rpoB 526 and rpoB 516 were the most frequently. Analysis of the rpoB gene of 3077 RIF-susceptible strains revealed that 98.96% of the strains had no mutation. The distribution of mutation frequency at differentcritical codons in different regions of China was statistically significant (p = 0.001). There was no significant difference in the occurrence of mutations at critical codons between the rifampicin-resistant Bei-jing and non-Beijing isolates.Conclusion: About 98% of RIF-resistant strains isolated from China carry mutations in RRDR ofrpoB gene.Mutation profiles in RIF-resistantM. tuberculosis clinical isolates are variable depending on the different geographical regionsof China. The results provide valuable information in adopting new molecular methods for diagnosis of TB in China.
文摘With the rapid development of the individualized demand market,the demand for manufacturing flexibility has increased over time.As a result,a cell manufacturing system suitable for many varieties and small batches has been produced.With the goal of minimizing the area and logistics handling volume,and considering the arrangement order of facilities and channel constraints,a mathematical model was established,and the problem was solved by improved NSGA-II.After non-dominated sorting,traditional NSGA-II will cross-operate the individuals with the best sorting to generate new individuals.Such a selection strategy is extremely easy to fall into the local optimal solution.The improved NSGA-II is to improve the original selection operation,which is to select the first half of the excellent individuals in the non-dominated sorting into the cross operation,and then select the last sorted ones of the remaining individuals into the cross operation,and combine the best and the worst ones into the cross operation.Finally,an example is given to simulate and improve the solution of NSGA-II and NSGA-II.The simulation results indicate that the improved NSGA-II population shows more obvious diversity,it is easier to jump out of the local optimal solution than NSGA-II,and the satisfactory layout scheme of manufacturing cells is obtained.Therefore,it is more effective to use improved NSGA-II to solve the problem of manufacturing cell layout.
文摘The authors regret that ‘Houquan Zhang’applies to remove his name and affiliation from the author list because he thought that he didn't make enough great contributions to this paper,just dis-cus:sion about the outline for the paper writing and some revision suggestions.The correct author list and affi liations are updated as above.
文摘To distinguish Mycobacterium tuberculosis from Mycobacterium avium, specific M. tuberculosis antigens had been studied for improving the early differential diagnosis effect of tuberculosis caused by different Mycobacterium. The rabbit anti-M. avium sera and anti-M. tuberculosis sera were analyzed for antibody-based reactivity by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-TOF Mass) against M. tuberculosis proteins. The immunoreactive spots, which were attributed to the proteins HspX, GroES and CFP-10, were mostly located at 10 - 60 kDa and PI 4 - 6, subsequently Western blotting result proved that HspX and CFP-10 were specific to M. tuberculosis and ELISA testing result of 30 M. avium positive sera showed that GroES were cross-reactive to M. avium. Lastly, positive and negative tuberculosis reference sera and based on the mechanism of indirect ELISA, the specificity and the sensitivity of the methods targeting the antibodies HspX, GroES or CFP-10 were evaluated at 37% and 26%, 12% and 97%, 81% and 98%, respectively. The combination of these three antibody detection methods allowed to reached a specificity of 42%, and of 39% without taken into account of the method targeting the GroES antibody. Using proteomics approach, we found three M. tuberculosis specific antigens showed good potential in tuberculosis diagnosis, providing basic study for serodiagnosis of tuberculosis.
文摘This paper addresses the World Tuberculosis(TB)Day 2025 theme,“Yes!We can end TB!Commit,Invest,Deliver”.Through comprehensive analysis of China’s TB epidemic landscape and associated challenges,we align with the“National TB Prevention and Control Plan(2024−2030)”which emphasizes that building Zero-TB communities through the integration of“active case finding”and“TB preventive treatment(TPT)”represents a viable pathway toward ending the TB epidemic.Active case finding serves as a critical intervention for early detection and transmission reduction,while TPT constitutes an essential strategy for decreasing latent TB infection incidence.By facilitating the rapid expansion of Zero-TB communities through governmental commitment,strategic resource allocation,and coordinated implementation,we anticipate achieving the ultimate goal of TB epidemic elimination.
文摘Background Most high tuberculosis(TB)burden countries are in low-and middle-income regions undergoing rapid urbanization.We aimed to assess the association between urbanization factors and TB incidence in China.Methods We evaluated urbanization at the county level in China from 2005 to 2019 using a composite index integrating pop-ulation density,gross domestic product(GDP,per capita),hospital beds per 10o0 population,nighttime light(NTL),and normal-ized difference vegetation index(NDVI).The annual incidence rate and number of TB cases were obtained from the national Tuberculosis Information Management System,maintained by the Chinese Center for Disease Control and Prevention.Fixed-effects models were used to examine the association between urbanization factors and TB incidence.A subgroup analysis Was performed by dividing counties into four regions:northeast,eastern,central,and western.Results A total of 1992 counties in China were included in this study.Overall,urbanization scores were associated with reduced TB incidence(β=-0.0114,P<0.001),corresponding to a 1.1%reduction in TB incidence per unit score.Quadratic models presented a U-shaped relationship between urbanization and TB incidence with an inflection point at 52.94 urbanization units.For each indicator of urbanization,population density and the number of hospital beds were positively associated with TB incidence,with incidence rate ratios of 11.384[95%confidence interval(Cl):9.337 to 13.881],and 1.015(95%C/:1.011 to 1.019),respectively,while GDP,NTL,and NDVI exhibited protective effects.Cen-tral China displayed an increase trend that urbanization score was linked to a 1.8%rise in TB incidence.Conclusions Urbanization-related factors,including GDP,NTL and NDVI,were inversely associated with TB incidence.Central China's contrasting results highlighted region-specific challenges.Therefore,governments in developing countries should adopt integrated approaches that promote both economic growth and sustainable development of environment during urbanization to optimize TB control efforts.
基金supported by the National Infectious Disease Medical Center(B2022011-1)Jinan Microecological Biomedicine Shandong Laboratory project(JNL-2022050B)。
文摘The 2024World Health Organization(WHO)Global Tuberculosis Report underscores progress and persisting challenges in the fight against tuberculosis(TB).1 TB remains a significant global health concern,with a slight stabilization in the incidence rate following disruptions caused by the COVID-19 pandemic.However,achieving the goals of the End TB Strategy by 2035 requires more accelerated efforts.2 The report reveals that,while the global rise in TB incidence has slowed,the number of people falling ill with TB continues to rise,highlighted by a global estimate of 10.8 million TB cases in 2023,with 30 high TB burden countries accounting for 87%of the global total TB cases.It is noteworthy that five countries accounted for 56%of the global TB burden,with India contributing the largest share at 26%,followed by Indonesia at 10%,China at 6.8%,the Philippines at 6.8%and Pakistan at 6.3%.Despite a reduction in TB deaths globally(approximately 1.25 million in 2023 compared with 1.32 million in 2022),TB has reclaimed its position as the leading cause of death from a single infectious agent,surpassing COVID-19.TB deaths are primarily due to complications resulting from untreated or poorly managed TB infections.The leading causes of death include the progression of pulmonary TB and TB with HIV/AIDS.Highmortality TB diseases such as tuberculous meningitis,miliary TB and disseminated TB remain critically neglected,receiving insufficient attention and lacking adequate treatment strategies.3–6 Addressing this neglect requires urgent investment in advanced diagnostics,personalized treatments and innovative drug therapies.Expanding healthcare capacity and establishing effective treatment standards are vital to combating these overlooked diseases and reducing mortality,particularly amid rising drug resistance.
基金Supported by the project“Epidemic of Tuberculosis Recurrence and Types of Recent Recurrence in Western China”(JY22-3-11)the Chinese Center for Disease Control and Prevention,and the National Natural Science Foundation of China(72174004).
文摘Summary What is already known about this topic?The recurrence of tuberculosis(TB)following successful treatment presents a significant challenge.What is added by this report?Achieving the global End TB Strategy milestones and targets with the current strategies in China is challenging.However,interventions following recovery to prevent recurrence,in conjunction with preventive treatment for latent TB infection(LTBI),will aid in meeting these objectives.
基金National Key Research and Development Project(2022YFC2305200,2022YFC2602200)Natural Science Foundation of Shenzhen(JCYJ20210324130009024)。
文摘Background Patients with tuberculosis resistant to isoniazid but susceptible to rifampicin(Hr-Rs TB)remain a neglected demographic,despite a high disease burden and poor outcomes of these patients.The aim of this study was to investigate the characteristics of isoniazid-resistance-related mutations in Mycobacterium tuberculosis and resistance rates to drugs included in WHO-recommended regimens for Hr-Rs patients.Methods Mycobacterium tuberculosis isolates(n=4922)obtained from national tuberculosis drug-resistance surveillance were subjected to whole-genome sequencing to identify Hr-Rs strains.The minimal inhibitory concentrations(MICs)were established for the Hr-Rs strains to determine the isoniazid resistance levels.We also identified drug-resistance-associated mutations for five drugs(fluoroquinolones,ethambutol,pyrazinamide,streptomycin,and amikacin)in the Hr-Rs strains.Results Of the 4922 strains,384(7.8%)were Hr-Rs.The subculture of seven strains failed,so 377(98.2%)strains underwent phenotypic MIC testing.Among the 384 genotypic Hr-Rs strains,242(63.0%)contained the katG Ser315Thr substitution;115(29.9%)contained the-15C>T in the promoter region of the fabG1 gene;and 16(4.2%)contained Ser315Asn in the katG gene.Of the 239 strains with the Ser315Thr substitution,229(95.8%)had MIC≥2µg/mL,and of the 114 strains with the-15C>T mutation,103(90.4%)had 0.25µg/mL≤MIC≤1µg/mL.The genotypic resistance rates were 0.8%(3/384)for pyrazinamide,2.3%(9/384)for ethambutol and fluoroquinolones;39.6%(152/384)of the strains were resistant to streptomycin,but only 0.5%(2/384)of the strains were resistant to amikacin.Conclusion Ser315Thr in katG was the predominant mutation conferring the Hr-Rs phenotype,followed by the fabG1-15C>T mutation.The combination of rifampicin,pyrazinamide,ethambutol,and levofloxacin should be effective in the treatment of patients with Hr-Rs tuberculosis because the resistance rates for these drugs in China are low.
基金This work was supported by the Epidemic of Tuberculosis Recurrence and Types of Recent Recurrence in Western China(JY22-3-11),Chinese Center for Disease Control and Prevention.
文摘Summary What is already known about this topic?The coronavirus disease(COVID-19)pandemic could have a damaging impact on access to tuberculosis(TB)diagnosis and treatment.What is added by this report?The overall delay experienced by TB patients during the COVID-19 pandemic has shown a modest decrease in comparison to the period before the pandemic.Notably,higher patient delays were observed among agricultural workers and those identified through passive case-finding methods.Furthermore,the patient delay in eastern regions was shorter compared to western and central regions.
文摘Introduction:National Notifiable Disease Reporting System(NNDRS)plays an important role in the early detection and control of tuberculosis(TB)in China.This study analyzed the epidemiological characteristics of pulmonary tuberculosis(PTB)in Kashgar Prefecture,Xinjiang Uygur Autnomous Region,China from 2011 to 2020 to provide a scientific basis for developing TB control strategies and measures in Kashgar.Methods:The data were collected from the NNDRS,which included the geographical distribution,age,sex,occupation,and pathogenic classification of reported PTB cases in 12 counties/cities of Kashgar Prefecture from 2011 to 2020.Descriptive statistics were used to describe the characteristic of PTB epidemic in Kashgar.Results:There were 189,416 PTB cases reported during 2011–2020,with a mean annual PTB case notification rate(CNR)of 451.29/100,000.A rising trend in the rate of reported PTB between 2011 and 2017(χ2 trend=26.09,P<0.01)and a declining trend between 2018 and 2020(χ2 trend=314.44,P<0.01)were observed.The months with the highest reported number of PTB cases were March to May and November to December.The mean annual rate of reported PTB was 451.88/100,000 for males and 450.67/100,000 for females.In addition,19.76%of patients were bacteriologically-confirmed(Bac+)cases(37,425/189,416),and the mean annual Bac+CNR was 89.17/100,000,rising from 64.76/100,000 in 2011 to 139.12/100,000 in 2020(χ^(2)_(trend)=74.44,P<0.01).Conclusions:The CNR of reported PTB in Kashgar showed a significant declining trend in the past three years.Males,elderly population,winter and spring,and farmers as an occupation were the main factors associated with high incidence of tuberculosis in Kashgar.Targeted prevention and treatment of TB should be strengthened in key groups in this region.
