High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,...High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,N2physisorption,27Al magic angle spinning nuclear magnetic resonance(MAS NMR),and temperature-programmed desorption of ammonia results indicated that the hightemperature treatment at 650℃ hardly affected the inherent crystal and texture of HZSM-5zeolites but facilitated the conversion of framework Al to extra-framework Al,reducing the acid site and enhancing the acid strength.Moreover,the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking,promoting the conversion and light olefins yield while inhibiting coke formation.Based on the kinetic and mechanism analysis,the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al,which enhanced the acid strength,facilitated the bimolecular reaction,and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking.展开更多
With the continuous development of civil engineering,concrete crack treatment technology has become an important research field.This paper proposes treatment techniques for different types of cracks,including the prev...With the continuous development of civil engineering,concrete crack treatment technology has become an important research field.This paper proposes treatment techniques for different types of cracks,including the prevention and repair of surface cracks,the reinforcement and grouting of structural cracks,and the design and construction of controlled cracks through the analysis of the causes and classification of concrete cracks.The methods and suggestions proposed in this paper are practical and can improve the quality and safety of buildings.展开更多
The present letter to the editor is related to the review with the title“Past,present,and future of long-term treatment for hepatitis B virus.”Chronic hepatitis B(CHB)represents an important and pressing public heal...The present letter to the editor is related to the review with the title“Past,present,and future of long-term treatment for hepatitis B virus.”Chronic hepatitis B(CHB)represents an important and pressing public health concern.Timely identification and effective antiviral therapy hold the potential to reduce liver-related mortality attributable to chronic infection with hepatitis B virus(HBV)substantially.However,the current global treatment rates for CHB remain conspicuously low,with the excessively stringent treatment criteria advocated by national CHB guidelines being a contributing factor to these low rates.Nevertheless,recent strides in comprehending this malady and the emergence of novel antiviral agents prompt the imperative re-evaluation of treatment standards to extend the sphere of potential beneficiaries.An impending need arises for a novel paradigm for the classification of patients with CHB,the expansion of antiviral treatment eligibility for HBV-infected individuals,and even the streamlining of the diagnostic process for CHB to amplify cost-effectiveness and augment survival prospects.展开更多
Nickel-based superalloys are extensively used in the crucial hot-section components of industrial gas turbines,aeronautics,and astronautics because of their excellent mechanical properties and corrosion resistance at ...Nickel-based superalloys are extensively used in the crucial hot-section components of industrial gas turbines,aeronautics,and astronautics because of their excellent mechanical properties and corrosion resistance at high temperatures.Fusion welding serves as an effective means for joining and repairing these alloys;however,fusion welding-induced liquation cracking has been a challenging issue.This paper comprehensively reviewed recent liquation cracking,discussing the formation mechanisms,cracking criteria,and remedies.In recent investigations,regulating material composition,changing the preweld heat treatment of the base metal,optimizing the welding process parameters,and applying auxiliary control methods are effective strategies for mitigating cracks.To promote the application of nickel-based superalloys,further research on the combination impact of multiple elements on cracking prevention and specific quantitative criteria for liquation cracking is necessary.展开更多
Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough ...Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough investigation into the behavior of crack propagation contributes to a better understanding and control of the properties of brittle materials,thereby enhancing the reliability and safety of both materials and structures.As an implicit discrete elementmethod,the Discontinuous Deformation Analysis(DDA)has gained significant attention for its developments and applications in recent years.Among these developments,the particle DDA equipped with the bonded particle model is a powerful tool for predicting the whole process of material from continuity to failure.The primary objective of this research is to develop and utilize the particle DDAtomodel and understand the complex behavior of cracks in brittle materials under both static and dynamic loadings.The particle DDA is applied to several classical crack propagation problems,including the crack branching,compact tensile test,Kalthoff impact experiment,and tensile test of a rectangular plate with a hole.The evolutions of cracks under various stress or geometrical conditions are carefully investigated.The simulated results are compared with the experiments and other numerical results.It is found that the crack propagation patterns,including crack branching and the formation of secondary cracks,can be well reproduced.The results show that the particle DDA is a qualified method for crack propagation problems,providing valuable insights into the fracture mechanism of brittle materials.展开更多
Seismic prediction of cracks is of great significance in many disciplines,for which the rock physics model is indispensable.However,up to now,multitudinous analytical models focus primarily on the cracked rock with th...Seismic prediction of cracks is of great significance in many disciplines,for which the rock physics model is indispensable.However,up to now,multitudinous analytical models focus primarily on the cracked rock with the isotropic background,while the explicit model for the cracked rock with the anisotropic background is rarely investigated in spite of such case being often encountered in the earth.Hence,we first studied dependences of the crack opening displacement tensors on the crack dip angle in the coordinate systems formed by symmetry planes of the crack and the background anisotropy,respectively,by forty groups of numerical experiments.Based on the conclusion from the experiments,the analytical solution was derived for the effective elastic properties of the rock with the inclined penny-shaped cracks in the transversely isotropic background.Further,we comprehensively analyzed,according to the developed model,effects of the crack dip angle,background anisotropy,filling fluid and crack density on the effective elastic properties of the cracked rock.The analysis results indicate that the dip angle and background anisotropy can significantly either enhance or weaken the anisotropy degrees of the P-and SH-wave velocities,whereas they have relatively small effects on the SV-wave velocity anisotropy.Moreover,the filling fluid can increase the stiffness coefficients related to the compressional modulus by reducing crack compliance parameters,while its effects on shear coefficients depend on the crack dip angle.The increasing crack density reduces velocities of the dry rock,and decreasing rates of the velocities are affected by the crack dip angle.By comparing with exact numerical results and experimental data,it was demonstrated that the proposed model can achieve high-precision estimations of stiffness coefficients.Moreover,the assumption of the weakly anisotropic background results in the consistency between the proposed model and Hudson's published theory for the orthorhombic rock.展开更多
This research explores strategies to enhance the efficiency of secondary treatment in Vertical Flow Constructed Wetlands (CW) in Montenegro. The focus is on selecting appropriate primary treatment methods alongside th...This research explores strategies to enhance the efficiency of secondary treatment in Vertical Flow Constructed Wetlands (CW) in Montenegro. The focus is on selecting appropriate primary treatment methods alongside three distinct substrate types to improve wastewater treatment efficacy. The study examines the combination of two primary treatments with different substrate types in constructed wetlands (CW1, CW2, and CW3). The primary treatments include the existing wastewater treatment plant (WWTP) in Podgorica, involving coarse material removal through screens, inert material separation in aerated sand traps, and sediment and suspended matter removal in primary sedimentation tanks. The Extreme Separator (ExSep) was employed to evaluate its efficacy as a primary treatment method. The research demonstrates that the efficiency of CW can be significantly enhanced by selecting suitable primary treatment methods and substrates in Podgorica’s conditions. The most promising results were achieved by combining ExSep as a primary treatment with secondary treatment in CW-3. The removal efficiencies after CW3 for COD, BOD, and TSS exceeded 89%, 93%, and 91%, respectively. The outcomes underscore the significance of primary treatment in mitigating pollutant loads before discharge into the constructed wetlands, emphasizing potential areas for further optimization in wastewater treatment practices to enhance environmental sustainability and water quality management.展开更多
Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tes...Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were conducted.The rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of corrosion.In air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking paths.Compared with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack tip.The corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of specimen.However,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic dissolution.Owing to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.展开更多
Hodgkin's lymphoma(HL)is a common,malignant hematological tumor of the lymph nodes and lymphatic system,accounting for 10%of all lymphomas.HL comprises 2 main subtypes:classical HL(cHL)and nodular lymphocyte predo...Hodgkin's lymphoma(HL)is a common,malignant hematological tumor of the lymph nodes and lymphatic system,accounting for 10%of all lymphomas.HL comprises 2 main subtypes:classical HL(cHL)and nodular lymphocyte predominant HL.展开更多
Fullerenes:The extensive development of nanoscience that has marked this century continues to evolve,producing new materials,structures,and devices for the treatments of diverse pathologies.Fullerenes are a family of ...Fullerenes:The extensive development of nanoscience that has marked this century continues to evolve,producing new materials,structures,and devices for the treatments of diverse pathologies.Fullerenes are a family of nanoparticles with great applicative promise due to their small size(approximately 1 nm in diameter),structure,and capacity to cross biological barriers.展开更多
Non-invasive brain stimulation techniques(NIBS),including repetitive transcranial magnetic stimulation(rTMS) and transcranial electric stim ulation(tES),are increasingly being adopted clinically for treatment of neuro...Non-invasive brain stimulation techniques(NIBS),including repetitive transcranial magnetic stimulation(rTMS) and transcranial electric stim ulation(tES),are increasingly being adopted clinically for treatment of neuropsychiatric and neurological disorders,albeit with varying success.The rationale behind the use of NIBS has historically been that stim ulation techniques modulate neuronal activity in the targeted region and consequently induce plasticity which can lead to therapeutic outcomes.展开更多
Over the past few decades,exercise oncology has emerged as an important subfield within exercise science.Over that time,substantial progress has been made in understanding the role of exercise in people newly diagnose...Over the past few decades,exercise oncology has emerged as an important subfield within exercise science.Over that time,substantial progress has been made in understanding the role of exercise in people newly diagnosed with cancer,actively being treated for cancer,and recovering after cancer treatments.展开更多
Red-bed mudstone, prevalent in southwest China, poses a formidable challenge due to its hydrophilic clay minerals, resulting in expansion, deformation, and cracking upon exposure to moisture. This study addresses upli...Red-bed mudstone, prevalent in southwest China, poses a formidable challenge due to its hydrophilic clay minerals, resulting in expansion, deformation, and cracking upon exposure to moisture. This study addresses uplift deformation disasters in high-speed railways by employing a moisture diffusion-deformation-fracture coupling model based on the finite-discrete element method(FDEM). The model integrates the influence of cracks on moisture diffusion. The investigation into various excavation depths reveals a direct correlation between depth and the formation of tensile cracks at the bottom of the railway cutting. These cracks expedite moisture migration, significantly impacting the temporal and spatial evolution of the moisture field. Additionally, crack expansion dominates hygroscopic deformation, with the lateral coordinate of the crack zone determining peak vertical displacement. Furthermore, key factors influencing deformation in railway cuttings, including the swelling factor and initial moisture content at the bottom of the cutting, are explored. The number of tensile and shear cracks increases with greater excavation depth, particularly concerning shear cracks. Higher swelling factors and initial moisture contents result in an increased total number of cracks, predominantly shear cracks. Numerical calculations provide valuable insights, offering a scientific foundation and directional guidance for the precise prevention, control, prediction, and comprehensive treatment of mudstone-related issues in high-speed railways.展开更多
To the editor:In the USA alone,there were 1.7 million suicide attempts in 2021.1 Although the majority of suicide attempts are not fatal,immediate medical attention is often necessary,especially when violent methods a...To the editor:In the USA alone,there were 1.7 million suicide attempts in 2021.1 Although the majority of suicide attempts are not fatal,immediate medical attention is often necessary,especially when violent methods are used.2 These methods include jumping from heights,using a firearm,crashing a motor vehicle,and lying down or jumping in front of a moving object.展开更多
To the Editor:SARS-CoV-2,the pathogen responsible for the pandemic of coronavirus disease 2019(COVID-19),has had profound impacts on human health,and its antagonist Paxlovid is a commonly used treatment option[1].Howe...To the Editor:SARS-CoV-2,the pathogen responsible for the pandemic of coronavirus disease 2019(COVID-19),has had profound impacts on human health,and its antagonist Paxlovid is a commonly used treatment option[1].However,treatment selection for immunosuppressed patients,such as liver recipients,remains uncertain due to potential drug interactions and the risk of immunosuppressant dosage adjustment,which can cause liver injury[2].展开更多
The Annual Report on Cardiovascular Health and Diseases in China(2022)intricate landscape of cardiovascular health in China.This is the third section of the report with a specific focus on community-based prevention a...The Annual Report on Cardiovascular Health and Diseases in China(2022)intricate landscape of cardiovascular health in China.This is the third section of the report with a specific focus on community-based prevention and treatment of cardiovascular diseases(CVD).This section of the report underscores the importance of initiatives outlined in the"Healthy China 2030 Plan,"emphasizing the comprehensive prevention and control strategy for chronic diseases.A key aspect of this plan involves the establishment of national demonstration areas aimed at comprehensive prevention and control of chronic diseases.By 2020,488 such areas had been set up across China,surpassing the initial target and covering a significant proportion of counties and districts.The report highlights the successful implementation of these strategies in Lishan district,Anshan city,where demonstration areas for comprehensive prevention and control of chronic diseases were launched in 2013.Over the course of seven years,the number of healthy units increased substantially,leading to improvements in managing risk factors for CVD among residents.Significant reductions in prevalence rates of overweight,obesity,smoking,passive smoking,and drinking were observed,along with the development of healthier behaviors among residents.Similarly,Qiaokou district in Wuhan City,designated as a national demonstration area in 2014,implemented comprehensive public health promotion initiatives.Notably,special clinics for hypertension intervention were established,contributing to an increase in self-reported rates of hypertension,a slight decrease in prevalence,and a remarkable improvement in the control rate among treated patients.Overall,these efforts underscore the effectiveness of community-based approaches in driving positive health outcomes and advancing the comprehensive prevention and control of chronic diseases,particularly cardiovascular diseases,in China.展开更多
Red clay landslides are widely distributed worldwide,resulting in severe loss of life and property.Although rainfall-induced red clay slopes have received extensive attention,the role of cracks in the evolutionary pro...Red clay landslides are widely distributed worldwide,resulting in severe loss of life and property.Although rainfall-induced red clay slopes have received extensive attention,the role of cracks in the evolutionary process of red clay slopes and their connection to failure mechanisms is still poorly understood.A comprehensive approach integrating field investigation,laboratory tests,and numerical simulations was conducted to study the 168 red clay landslides in Xinshao County,China.The results show that red clay is prone to forming cracks at high moisture content due to its low swelling and high shrinkage properties.The failure mode of red clay slopes can be summarized in three stages:crack generation,slope excavation,and slope failure.Furthermore,the retrospective analysis and numerical simulations of the typical landslide in Guanchong indicated that intense rainfall primarily impacts the shallow layer of soil within approximately 0.5 m on the intact slope.However,cracks change the pattern of rainfall infiltration in the slope.Rainwater infiltrates rapidly through the preferential channels induced by the cracks rather than uniformly and slowly from the slope surface.This results in a significant increase in both the depth of infiltration and the saturated zone area of the cracked slope,reaching 3.8 m and 36.2 m^(2),respectively.Consequently,the factor of safety of the slope decreases by 13.4%compared to the intact slope,ultimately triggering landslides.This study can provide valuable insights into understanding the failure mechanisms of red clay slopes in China and other regions with similar geological settings.展开更多
Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy wa...Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC process.With regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li interfaces.Moreover,the SCC of the two alloys was concerned with hydrogen embrittlement(HE)mechanism.展开更多
Introduction: Medical treatment for POAG is continuous and lifelong treatment. The aim of this study was to evaluate the relationship between the cost of this treatment and patients’ income and the impact of this rel...Introduction: Medical treatment for POAG is continuous and lifelong treatment. The aim of this study was to evaluate the relationship between the cost of this treatment and patients’ income and the impact of this relationship on treatment compliance. Materials and Methods: Prospective cross-sectional study with a descriptive aim covering sociodemographic data, average incomes, and direct and indirect costs of treatment of 57 patients followed for POAG during the period from January 1, 2012, to December 31, 2016 (5 years). Results: The patients were aged 25 to 77 years (mean = 54.4 years) with a male predominance (sex ratio = 1.5). Retirees were the most represented (26.32%), followed by workers in the informal sector (14.04%) and housewives (12.28%). Patients who had an annual income less than or equal to 900,000 CFA francs (€1370.83) per year represented 56.14% and those who did not have health coverage represented 57.89%. The treatment was monotherapy (64.91%), dual therapy (31.58%) or triple therapy (3.05%) and the average ratio of “annual cost of treatment to annual income” was 0.56 with for maximum 2.23 and 0.02 as minimum. Patients who considered the cost of treatment unbearable for their income represented 78.95%. Conclusion: Prevention of blindness due to glaucoma requires early detection but also the establishment of health coverage mechanisms to improve compliance with medical treatment. In addition, consideration should be given to the development of glaucoma surgery in our country, the indication of which could be the first intention in certain patients, considering for those patients, the geographical and financial accessibility of medical treatment. .展开更多
The treatment of patients with inflammatory bowel disease(IBD),especially those with severe or refractory disease,represents an important challenge for the clinical gastroenterologist.It seems to be no exaggeration to...The treatment of patients with inflammatory bowel disease(IBD),especially those with severe or refractory disease,represents an important challenge for the clinical gastroenterologist.It seems to be no exaggeration to say that in these patients,not only the scientific background of the gastroenterologist is tested,but also the abundance of“gifts”that he should possess(insight,intuition,determ-ination,ability to take initiative,etc.)for the successful outcome of the treatment.In daily clinical practice,depending on the severity of the attack,IBD is treated with one or a combination of two or more pharmaceutical agents.These combin-ations include not only the first-line drugs(e.g.,mesalazine,corticosteroids,antibiotics,etc)but also second-and third-line drugs(immunosuppressants and biologic agents).It is a fact that despite the significant therapeutic advances there is still a significant percentage of patients who do not satisfactorily respond to the treatment applied.Therefore,a part of these patients are going to surgery.In recent years,several small-size clinical studies,reviews,and case reports have been published combining not only biological agents with other drugs(e.g.,immunosuppressants or corticosteroids)but also the combination of two biologi-cal agents simultaneously,especially in severe cases.In our opinion,it is at least a strange(and largely unexplained)fact that we often use combinations of drugs in a given patient although studies comparing the simultaneous administration of two or more drugs with monotherapy are very few.As mentioned above,there is a timid tendency in the literature to combine two biological agents in severe cases unresponsive to the applied treatment or patients with severe extraintestinal manifestations.The appropriate dosage,the duration of the administration,the suitable timing for checking the clinical and laboratory outcome,as well as the treatment side-effects,should be the subject of intense clinical research shortly.In this editorial,we attempt to summarize the existing data regarding the already applied combination therapies and to humbly formulate thoughts and suggestions for the future application of the combination treatment of biological agents in a well-defined category of patients.We suggest that the application of biomarkers and artificial intelligence could help in establishing new forms of treatment using the available modern drugs in patients with IBD resistant to treatment.展开更多
基金the financial support from the National Natural Science Foundation of China(21908010)Jilin Provincial Department of Science and Technology(20220101089JC)the Education Department of Jilin Province(JJKH20220694KJ)。
文摘High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,N2physisorption,27Al magic angle spinning nuclear magnetic resonance(MAS NMR),and temperature-programmed desorption of ammonia results indicated that the hightemperature treatment at 650℃ hardly affected the inherent crystal and texture of HZSM-5zeolites but facilitated the conversion of framework Al to extra-framework Al,reducing the acid site and enhancing the acid strength.Moreover,the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking,promoting the conversion and light olefins yield while inhibiting coke formation.Based on the kinetic and mechanism analysis,the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al,which enhanced the acid strength,facilitated the bimolecular reaction,and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking.
文摘With the continuous development of civil engineering,concrete crack treatment technology has become an important research field.This paper proposes treatment techniques for different types of cracks,including the prevention and repair of surface cracks,the reinforcement and grouting of structural cracks,and the design and construction of controlled cracks through the analysis of the causes and classification of concrete cracks.The methods and suggestions proposed in this paper are practical and can improve the quality and safety of buildings.
文摘The present letter to the editor is related to the review with the title“Past,present,and future of long-term treatment for hepatitis B virus.”Chronic hepatitis B(CHB)represents an important and pressing public health concern.Timely identification and effective antiviral therapy hold the potential to reduce liver-related mortality attributable to chronic infection with hepatitis B virus(HBV)substantially.However,the current global treatment rates for CHB remain conspicuously low,with the excessively stringent treatment criteria advocated by national CHB guidelines being a contributing factor to these low rates.Nevertheless,recent strides in comprehending this malady and the emergence of novel antiviral agents prompt the imperative re-evaluation of treatment standards to extend the sphere of potential beneficiaries.An impending need arises for a novel paradigm for the classification of patients with CHB,the expansion of antiviral treatment eligibility for HBV-infected individuals,and even the streamlining of the diagnostic process for CHB to amplify cost-effectiveness and augment survival prospects.
基金financially supported by the National Science and Technology Major Project of China(No.J2019-VI-0004-0117)。
文摘Nickel-based superalloys are extensively used in the crucial hot-section components of industrial gas turbines,aeronautics,and astronautics because of their excellent mechanical properties and corrosion resistance at high temperatures.Fusion welding serves as an effective means for joining and repairing these alloys;however,fusion welding-induced liquation cracking has been a challenging issue.This paper comprehensively reviewed recent liquation cracking,discussing the formation mechanisms,cracking criteria,and remedies.In recent investigations,regulating material composition,changing the preweld heat treatment of the base metal,optimizing the welding process parameters,and applying auxiliary control methods are effective strategies for mitigating cracks.To promote the application of nickel-based superalloys,further research on the combination impact of multiple elements on cracking prevention and specific quantitative criteria for liquation cracking is necessary.
基金supported by the National Natural Science Foundation of China(Grant No.42372310).
文摘Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough investigation into the behavior of crack propagation contributes to a better understanding and control of the properties of brittle materials,thereby enhancing the reliability and safety of both materials and structures.As an implicit discrete elementmethod,the Discontinuous Deformation Analysis(DDA)has gained significant attention for its developments and applications in recent years.Among these developments,the particle DDA equipped with the bonded particle model is a powerful tool for predicting the whole process of material from continuity to failure.The primary objective of this research is to develop and utilize the particle DDAtomodel and understand the complex behavior of cracks in brittle materials under both static and dynamic loadings.The particle DDA is applied to several classical crack propagation problems,including the crack branching,compact tensile test,Kalthoff impact experiment,and tensile test of a rectangular plate with a hole.The evolutions of cracks under various stress or geometrical conditions are carefully investigated.The simulated results are compared with the experiments and other numerical results.It is found that the crack propagation patterns,including crack branching and the formation of secondary cracks,can be well reproduced.The results show that the particle DDA is a qualified method for crack propagation problems,providing valuable insights into the fracture mechanism of brittle materials.
基金We would like to acknowledge all the reviewers and editors and the sponsorship of National Natural Science Foundation of China(42030103)the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(2021QNLM020001-6)the Laoshan National Laboratory of Science and Technology Foundation(LSKJ202203400).
文摘Seismic prediction of cracks is of great significance in many disciplines,for which the rock physics model is indispensable.However,up to now,multitudinous analytical models focus primarily on the cracked rock with the isotropic background,while the explicit model for the cracked rock with the anisotropic background is rarely investigated in spite of such case being often encountered in the earth.Hence,we first studied dependences of the crack opening displacement tensors on the crack dip angle in the coordinate systems formed by symmetry planes of the crack and the background anisotropy,respectively,by forty groups of numerical experiments.Based on the conclusion from the experiments,the analytical solution was derived for the effective elastic properties of the rock with the inclined penny-shaped cracks in the transversely isotropic background.Further,we comprehensively analyzed,according to the developed model,effects of the crack dip angle,background anisotropy,filling fluid and crack density on the effective elastic properties of the cracked rock.The analysis results indicate that the dip angle and background anisotropy can significantly either enhance or weaken the anisotropy degrees of the P-and SH-wave velocities,whereas they have relatively small effects on the SV-wave velocity anisotropy.Moreover,the filling fluid can increase the stiffness coefficients related to the compressional modulus by reducing crack compliance parameters,while its effects on shear coefficients depend on the crack dip angle.The increasing crack density reduces velocities of the dry rock,and decreasing rates of the velocities are affected by the crack dip angle.By comparing with exact numerical results and experimental data,it was demonstrated that the proposed model can achieve high-precision estimations of stiffness coefficients.Moreover,the assumption of the weakly anisotropic background results in the consistency between the proposed model and Hudson's published theory for the orthorhombic rock.
文摘This research explores strategies to enhance the efficiency of secondary treatment in Vertical Flow Constructed Wetlands (CW) in Montenegro. The focus is on selecting appropriate primary treatment methods alongside three distinct substrate types to improve wastewater treatment efficacy. The study examines the combination of two primary treatments with different substrate types in constructed wetlands (CW1, CW2, and CW3). The primary treatments include the existing wastewater treatment plant (WWTP) in Podgorica, involving coarse material removal through screens, inert material separation in aerated sand traps, and sediment and suspended matter removal in primary sedimentation tanks. The Extreme Separator (ExSep) was employed to evaluate its efficacy as a primary treatment method. The research demonstrates that the efficiency of CW can be significantly enhanced by selecting suitable primary treatment methods and substrates in Podgorica’s conditions. The most promising results were achieved by combining ExSep as a primary treatment with secondary treatment in CW-3. The removal efficiencies after CW3 for COD, BOD, and TSS exceeded 89%, 93%, and 91%, respectively. The outcomes underscore the significance of primary treatment in mitigating pollutant loads before discharge into the constructed wetlands, emphasizing potential areas for further optimization in wastewater treatment practices to enhance environmental sustainability and water quality management.
基金the National Natural Science Foundation of China(Nos.52175143 and 51571150)。
文摘Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were conducted.The rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of corrosion.In air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking paths.Compared with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack tip.The corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of specimen.However,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic dissolution.Owing to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.
文摘Hodgkin's lymphoma(HL)is a common,malignant hematological tumor of the lymph nodes and lymphatic system,accounting for 10%of all lymphomas.HL comprises 2 main subtypes:classical HL(cHL)and nodular lymphocyte predominant HL.
基金supported by Ministarstvo Prosvete,Nauke i Tehnoloskog Razvoja,Grant/Award Number:451-03-9/2021-14/200007 and 451-03-9/2021-14/200017Zepter International Foundation,Grant/Award Number:5/2019(to Sl)。
文摘Fullerenes:The extensive development of nanoscience that has marked this century continues to evolve,producing new materials,structures,and devices for the treatments of diverse pathologies.Fullerenes are a family of nanoparticles with great applicative promise due to their small size(approximately 1 nm in diameter),structure,and capacity to cross biological barriers.
基金supported by the Bryant Stokes Neurological Research Fund (to JM)a fellowship from Multiple Sclerosis Western Australia (MSWA)+1 种基金the Perron Institute for Neurological and Translational Sciencethe Bryant Stokes Neurological Research Fund (to JR)。
文摘Non-invasive brain stimulation techniques(NIBS),including repetitive transcranial magnetic stimulation(rTMS) and transcranial electric stim ulation(tES),are increasingly being adopted clinically for treatment of neuropsychiatric and neurological disorders,albeit with varying success.The rationale behind the use of NIBS has historically been that stim ulation techniques modulate neuronal activity in the targeted region and consequently induce plasticity which can lead to therapeutic outcomes.
文摘Over the past few decades,exercise oncology has emerged as an important subfield within exercise science.Over that time,substantial progress has been made in understanding the role of exercise in people newly diagnosed with cancer,actively being treated for cancer,and recovering after cancer treatments.
基金funded by the National Natural Science Foundation of China (No. 42172308, No.51779018)the Youth Innovation Promotion Association CAS (No. 2022331)the Science and Technology Research and Development Program of China State Railway Group Co., Ltd. (No. J2022G002)。
文摘Red-bed mudstone, prevalent in southwest China, poses a formidable challenge due to its hydrophilic clay minerals, resulting in expansion, deformation, and cracking upon exposure to moisture. This study addresses uplift deformation disasters in high-speed railways by employing a moisture diffusion-deformation-fracture coupling model based on the finite-discrete element method(FDEM). The model integrates the influence of cracks on moisture diffusion. The investigation into various excavation depths reveals a direct correlation between depth and the formation of tensile cracks at the bottom of the railway cutting. These cracks expedite moisture migration, significantly impacting the temporal and spatial evolution of the moisture field. Additionally, crack expansion dominates hygroscopic deformation, with the lateral coordinate of the crack zone determining peak vertical displacement. Furthermore, key factors influencing deformation in railway cuttings, including the swelling factor and initial moisture content at the bottom of the cutting, are explored. The number of tensile and shear cracks increases with greater excavation depth, particularly concerning shear cracks. Higher swelling factors and initial moisture contents result in an increased total number of cracks, predominantly shear cracks. Numerical calculations provide valuable insights, offering a scientific foundation and directional guidance for the precise prevention, control, prediction, and comprehensive treatment of mudstone-related issues in high-speed railways.
文摘To the editor:In the USA alone,there were 1.7 million suicide attempts in 2021.1 Although the majority of suicide attempts are not fatal,immediate medical attention is often necessary,especially when violent methods are used.2 These methods include jumping from heights,using a firearm,crashing a motor vehicle,and lying down or jumping in front of a moving object.
基金The study was supported by grants from the National Natural Science Foundation of China(81871259,81971495,82070675,81530048,82200731 and 81570562)the Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials,and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘To the Editor:SARS-CoV-2,the pathogen responsible for the pandemic of coronavirus disease 2019(COVID-19),has had profound impacts on human health,and its antagonist Paxlovid is a commonly used treatment option[1].However,treatment selection for immunosuppressed patients,such as liver recipients,remains uncertain due to potential drug interactions and the risk of immunosuppressant dosage adjustment,which can cause liver injury[2].
文摘The Annual Report on Cardiovascular Health and Diseases in China(2022)intricate landscape of cardiovascular health in China.This is the third section of the report with a specific focus on community-based prevention and treatment of cardiovascular diseases(CVD).This section of the report underscores the importance of initiatives outlined in the"Healthy China 2030 Plan,"emphasizing the comprehensive prevention and control strategy for chronic diseases.A key aspect of this plan involves the establishment of national demonstration areas aimed at comprehensive prevention and control of chronic diseases.By 2020,488 such areas had been set up across China,surpassing the initial target and covering a significant proportion of counties and districts.The report highlights the successful implementation of these strategies in Lishan district,Anshan city,where demonstration areas for comprehensive prevention and control of chronic diseases were launched in 2013.Over the course of seven years,the number of healthy units increased substantially,leading to improvements in managing risk factors for CVD among residents.Significant reductions in prevalence rates of overweight,obesity,smoking,passive smoking,and drinking were observed,along with the development of healthier behaviors among residents.Similarly,Qiaokou district in Wuhan City,designated as a national demonstration area in 2014,implemented comprehensive public health promotion initiatives.Notably,special clinics for hypertension intervention were established,contributing to an increase in self-reported rates of hypertension,a slight decrease in prevalence,and a remarkable improvement in the control rate among treated patients.Overall,these efforts underscore the effectiveness of community-based approaches in driving positive health outcomes and advancing the comprehensive prevention and control of chronic diseases,particularly cardiovascular diseases,in China.
基金supported by the National Natural Science Foundation of China(Project No.41920104007 and 41772334).
文摘Red clay landslides are widely distributed worldwide,resulting in severe loss of life and property.Although rainfall-induced red clay slopes have received extensive attention,the role of cracks in the evolutionary process of red clay slopes and their connection to failure mechanisms is still poorly understood.A comprehensive approach integrating field investigation,laboratory tests,and numerical simulations was conducted to study the 168 red clay landslides in Xinshao County,China.The results show that red clay is prone to forming cracks at high moisture content due to its low swelling and high shrinkage properties.The failure mode of red clay slopes can be summarized in three stages:crack generation,slope excavation,and slope failure.Furthermore,the retrospective analysis and numerical simulations of the typical landslide in Guanchong indicated that intense rainfall primarily impacts the shallow layer of soil within approximately 0.5 m on the intact slope.However,cracks change the pattern of rainfall infiltration in the slope.Rainwater infiltrates rapidly through the preferential channels induced by the cracks rather than uniformly and slowly from the slope surface.This results in a significant increase in both the depth of infiltration and the saturated zone area of the cracked slope,reaching 3.8 m and 36.2 m^(2),respectively.Consequently,the factor of safety of the slope decreases by 13.4%compared to the intact slope,ultimately triggering landslides.This study can provide valuable insights into understanding the failure mechanisms of red clay slopes in China and other regions with similar geological settings.
基金the National Natural Science Foundation of China Projects under Grant[Nos.51871211,U21A2049,52071220,51701129 and 51971054]Liaoning Province’s project of"Revitalizing Liaoning Talents"(XLYC1907062)+10 种基金the Doctor Startup Fund of Natural Science Foundation Program of Liaoning Province(No.2019-BS-200)the Strategic New Industry Development Special Foundation of Shenzhen(JCYJ20170306141749970)the funds of International Joint Laboratory for Light AlloysLiaoning Bai Qian Wan Talents Programthe Domain Foundation of Equipment Advance Research of 13th Five-year Plan(61409220118)National Key Research and Development Program of China under Grant[Nos.2017YFB0702001 and 2016YFB0301105]the Innovation Fund of Institute of Metal Research(IMR)Chinese Academy of Sciences(CAS)the National Basic Research Program of China(973 Program)project under Grant No.2013CB632205the Fundamental Research Fund for the Central Universities under Grant[No.N2009006]Bintech-IMR R&D Program[No.GYY-JSBU-2022-009]。
文摘Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC process.With regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li interfaces.Moreover,the SCC of the two alloys was concerned with hydrogen embrittlement(HE)mechanism.
文摘Introduction: Medical treatment for POAG is continuous and lifelong treatment. The aim of this study was to evaluate the relationship between the cost of this treatment and patients’ income and the impact of this relationship on treatment compliance. Materials and Methods: Prospective cross-sectional study with a descriptive aim covering sociodemographic data, average incomes, and direct and indirect costs of treatment of 57 patients followed for POAG during the period from January 1, 2012, to December 31, 2016 (5 years). Results: The patients were aged 25 to 77 years (mean = 54.4 years) with a male predominance (sex ratio = 1.5). Retirees were the most represented (26.32%), followed by workers in the informal sector (14.04%) and housewives (12.28%). Patients who had an annual income less than or equal to 900,000 CFA francs (€1370.83) per year represented 56.14% and those who did not have health coverage represented 57.89%. The treatment was monotherapy (64.91%), dual therapy (31.58%) or triple therapy (3.05%) and the average ratio of “annual cost of treatment to annual income” was 0.56 with for maximum 2.23 and 0.02 as minimum. Patients who considered the cost of treatment unbearable for their income represented 78.95%. Conclusion: Prevention of blindness due to glaucoma requires early detection but also the establishment of health coverage mechanisms to improve compliance with medical treatment. In addition, consideration should be given to the development of glaucoma surgery in our country, the indication of which could be the first intention in certain patients, considering for those patients, the geographical and financial accessibility of medical treatment. .
文摘The treatment of patients with inflammatory bowel disease(IBD),especially those with severe or refractory disease,represents an important challenge for the clinical gastroenterologist.It seems to be no exaggeration to say that in these patients,not only the scientific background of the gastroenterologist is tested,but also the abundance of“gifts”that he should possess(insight,intuition,determ-ination,ability to take initiative,etc.)for the successful outcome of the treatment.In daily clinical practice,depending on the severity of the attack,IBD is treated with one or a combination of two or more pharmaceutical agents.These combin-ations include not only the first-line drugs(e.g.,mesalazine,corticosteroids,antibiotics,etc)but also second-and third-line drugs(immunosuppressants and biologic agents).It is a fact that despite the significant therapeutic advances there is still a significant percentage of patients who do not satisfactorily respond to the treatment applied.Therefore,a part of these patients are going to surgery.In recent years,several small-size clinical studies,reviews,and case reports have been published combining not only biological agents with other drugs(e.g.,immunosuppressants or corticosteroids)but also the combination of two biologi-cal agents simultaneously,especially in severe cases.In our opinion,it is at least a strange(and largely unexplained)fact that we often use combinations of drugs in a given patient although studies comparing the simultaneous administration of two or more drugs with monotherapy are very few.As mentioned above,there is a timid tendency in the literature to combine two biological agents in severe cases unresponsive to the applied treatment or patients with severe extraintestinal manifestations.The appropriate dosage,the duration of the administration,the suitable timing for checking the clinical and laboratory outcome,as well as the treatment side-effects,should be the subject of intense clinical research shortly.In this editorial,we attempt to summarize the existing data regarding the already applied combination therapies and to humbly formulate thoughts and suggestions for the future application of the combination treatment of biological agents in a well-defined category of patients.We suggest that the application of biomarkers and artificial intelligence could help in establishing new forms of treatment using the available modern drugs in patients with IBD resistant to treatment.