The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic...The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic tensile responses and asso-ciated uncertainty of rock mass.At first,the particle-based model was used synthesize the intact rock and split Hopkinson pressure bar(SHPB)system,while the fractures were represented using the smooth fracture model(SJM).Subsequently,the samples of the fractured rock mass with varying joint geometrical configurations were conducted the dynamic tensile test using the numerical SHPB system.The simulated results demonstrate a gradual decrease in dynamic tensile strength(TS)with increasing fracture intensity and fracture length,which can be effectively described by nonlinear exponential func-tions.Additionally,the fracture orientation significantly influences the dynamic TS,however,the anisotropic characteristics gradually diminish as the deviation angle approaches 90°.Furthermore,as fracture intensity and fracture length increase,the dynamic TS variability also rises steadily.However,no noticeable pattern is seen when considering cases with varying fracture orientations.When subjected to SHPB loading,the fractured rock mass primarily exhibits a combined tensile-shear failure mode,contrasting with the pure tensile failure mode exhibited by the intact rock.These findings contribute signifi-cantly to comprehending the dynamic tensile responses of the fractured rock mass and can further enhance the stability analysis of in-situ rock engineering.展开更多
The study of the mechanical property and damage state of coal materials under compression is a fundamental area of research in underground mining engineering.Drawing upon the compaction effect and linear energy dissip...The study of the mechanical property and damage state of coal materials under compression is a fundamental area of research in underground mining engineering.Drawing upon the compaction effect and linear energy dissipation(LED)law,a novel compressive damage constitutive model for brittle coal is proposed.Utilizing the energy-defined damage method for mate-rials,the LED law is innovatively introduced to accurately characterize the energy dissipation during the loading process,and a novel formula for characterizing the damage variable of brittle coal is proposed.On this basis,considering that the constitutive model based on the hypothesis of strain equivalence is incapable of accurately describing the compaction effect exhibited by coal material during the compression process,a correction coefficient is proposed and apply it in the novel damage constitutive model.The established conventional monotone loading and single-cyclic loading-unloading uniaxial compression damage constitutive models have been validated using experimental data from cylindrical and cuboid coal specimens.In addition,compared with the constitutive model obtained via the traditional energy calculation method based on the hypothesis that the unloading curve is a straight line,the constitutive model employing LED law can describe the stress-strain state of brittle coal more precisely.This approach introduces a new perspective and enhances the convenience for constructing the constitutive model based on energy theory.展开更多
Small-molecule ionic liquids(ILs)are frequently employed as efficient bulk phase modifiers for perovskite materials.However,their inherent characteristics,such as high volatility and ion migration properties,pose chal...Small-molecule ionic liquids(ILs)are frequently employed as efficient bulk phase modifiers for perovskite materials.However,their inherent characteristics,such as high volatility and ion migration properties,pose challenges in addressing the stability issues associated with perovskite solar cells(PSCs).In this study,we design a poly(IL)with multiple active sites,named poly[4-styrenesulfonyl(trifluoromethylsulfonyl)imide]pyri-dine(P[STFSI][PPyri]),as an efficient additive of perovskite materials.The S=O in the sulfonyl group chelates with uncoordinated Pb^(2+)and forms hydrogen bonds with the organic cations in the perovskite,suppressing the volatilization of the organic cations.The N+in pyridine can fix halide ions through electrostatic interaction with I-and Br-ions to prevent halide ion migration.P[STFSI][PPyri]demonstrates the ability to passivate defects and suppress nonradiative recombination in PSCs.Additionally,it facilitates the fixation of organic and halide ions,thereby enhancing the device’s stability and photoelectric performance.Consequently,the introduction of P[STFSI][PPyri]as a dopant in the devices resulted in an excellent efficiency of 24.62%,demonstrating outstanding long-term operational stability,with the encapsulated device maintaining 87.6%of its initial effi-ciency even after 1500 h of continuous maximum power point tracking.This strategy highlights the promising potential of poly(IL)as an effective additive for PSCs,providing a combination of high performance and stabil-ity.展开更多
Endowing metal halide hybrids(MHHs)with time-resolved emission and afterglow could significantly broaden their applications in fields such as information security and anti-counterfeiting.Nonetheless,there have been re...Endowing metal halide hybrids(MHHs)with time-resolved emission and afterglow could significantly broaden their applications in fields such as information security and anti-counterfeiting.Nonetheless,there have been relatively few successes in developing organic cations with persistent room-temperature phosphorescence(RTP)to construct MHHs with afterglow.In this work,we synthesize a new polyazole,3,5-di(1H-pyrazol-4-yl)-4H-1,2,4-triazol-4-amine(DPTA),with green persistent RTP up to 1.5 s.The afterglow of DPTA reaches up to∼1.0 s even after being assembled into 0D(DPTAH_(3))InCl_(6)·2.5H_(2)O(DIC).Due to strong overlap between the triplet emission of DPTA and ^(1)S0→^(3)Px absorption of Sb^(3+),efficient triplet energy transfer(TET)with the highest yield of 65.3%and a near-unity photoluminescence quantum yield(PLQY)is achieved.More importantly,the afterglow persistence time of DIC:x%Sb can be easily tailored through Sb^(3+)doping.Given the Sb^(3+)-dependent emission color and long persistence time,a series of DIC:x%Sb are successfully utilized to demonstrate high-security-level anti-counterfeiting application.This work shows an effective strategy for designing new MHHs with tunable emission and afterglow persistence time.展开更多
The ELI ERIC facility offers international users ultrashort laser sources via the ALPS facility focusing on few-cycle laser drivers for attosecond pulses,particle beams and ultrahigh intensity interactions.The HR1 sys...The ELI ERIC facility offers international users ultrashort laser sources via the ALPS facility focusing on few-cycle laser drivers for attosecond pulses,particle beams and ultrahigh intensity interactions.The HR1 system supports attosecond high harmonic generation(HHG)and time-resolved spectroscopy at 100 kHz.However,its high repetition rate,while aiding statistical analysis,poses thermal challenges and limits certain applications requiring lower repetition rates.To address this,the HR Alignment laser system was developed for the HHG beamline at the ELI-ALPS facility.This new system delivers sub-6 fs,1 mJ pulses with a tunable repetition rate(from 10 Hz to 10 kHz)and carrier-envelope phase(CEP)stabilization.It utilizes an ytterbium-doped potassium gadolinium tungstate front-end,multi-pass cell compression,and chirped mirrors.Characterization confirms excellent energy and CEP stability(below 300 mrad),beam quality and temporal contrast,matching the HR1 laser's performance.This compact,stable system provides highflux attosecond generation for reaction microscopy enhancing ultrafast research in the ELI-ALPS facility.展开更多
Nipah virus(NiV) and related viruses form a distinct henipavirus genus within the Paramyxoviridae family. NiV continues to spillover into the humans causing deadly outbreaks with increasing human-bat interaction. NiV ...Nipah virus(NiV) and related viruses form a distinct henipavirus genus within the Paramyxoviridae family. NiV continues to spillover into the humans causing deadly outbreaks with increasing human-bat interaction. NiV encodes the large protein(L) and phosphoprotein(P) to form the viral RNA polymerase machinery. Their sequences show limited homologies to those of non-henipavirus paramyxoviruses. We report two cryo-electron microscopy(cryo-EM) structures of the Nipah virus(NiV) polymerase L-P complex, expressed and purified in either its full-length or truncated form. The structures resolve the RNA-dependent RNA polymerase(RdRp) and polyribonucleotidyl transferase(PRNTase) domains of the L protein, as well as a tetrameric P protein bundle bound to the L-RdRp domain. L-protein C-terminal regions are unresolved, indicating flexibility. Two PRNTase domain zinc-binding sites, conserved in most Mononegavirales, are confirmed essential for NiV polymerase activity. The structures further reveal anchoring of the P protein bundle and P protein X domain(XD) linkers on L, via an interaction pattern distinct among Paramyxoviridae. These interactions facilitate binding of a P protein XD linker in the nucleotide entry channel and distinct positioning of other XD linkers. We show that the disruption of the L-P interactions reduces NiV polymerase activity. The reported structures should facilitate rational antiviral-drug discovery and provide a guide for the functional study of NiV polymerase.展开更多
Purpose:Injuries are one of the leading causes of death and lead to a high social and financial burden.Injury patterns can vary significantly among different age groups and body regions.This study aimed to evaluate th...Purpose:Injuries are one of the leading causes of death and lead to a high social and financial burden.Injury patterns can vary significantly among different age groups and body regions.This study aimed to evaluate the relationship between mechanism of injury,patient comorbidities and severity of injuries.Methods:The study included trauma patients from July 2016 to June 2018,who were admitted to Sina Hospital,Tehran,Iran.The inclusion criteria were all injured patients who had at least one of the following:hospital length of stay more than 24 h,death in hospital,and transfer from the intensive care unit of another hospital.Data collection was performed using the National Trauma Registry of Iran minimum dataset.Results:The most common injury mechanism was road traffic injuries(49.0%),followed by falls(25.5%).The mean age of those who fell was significantly higher in comparison with other mechanisms(p<0.001).Severe extremity injuries occurred more often in the fall group than in the vehicle collision group(69.0%vs.43.5%,p<0.001).Moreover,cases of severe multiple trauma were higher amongst vehicle collisions than injuries caused by falls(27.8%vs.12.9%,p=0.003).Conclusion:Comparing falls with motor vehicle collisions,patients who fell were older and sustained more extremity injuries.Patients injured by motor vehicle collision were more likely to have sustained multiple trauma than those presenting with falls.Recognition of the relationship between mechanisms and consequences of injuries may lead to more effective interventions.展开更多
Objectives:Bacillus cereus isolates from vegetables can cause diarrheal syndrome food poisoning.Lettuce,the most highly consumed readyto-eat vegetable,poses a signifcant risk of B.cereus exposure.Hence,B.cereus monito...Objectives:Bacillus cereus isolates from vegetables can cause diarrheal syndrome food poisoning.Lettuce,the most highly consumed readyto-eat vegetable,poses a signifcant risk of B.cereus exposure.Hence,B.cereus monitoring and evaluation during cultivation are essential for preventing foodborne illnesses caused by this food-pathogen combination.However,the impact of different cultivation practices on B.cereus contamination in lettuce currently remains unclear.Furthermore,a validity indicator for the experimental models cannot be effectively validated under feld conditions.Materials and Methods:Herein,we assessed the risk of B.cereus exposure using lettuce grown under two different cultivation farming systems in China(open-feld versus greenhouse)using a quantitative microbial risk assessment model.Tukey’s mean comparison method and kernel density estimation frequency distribution statistics were used for model validation using environmental samples and lettuce.Results:The mean concentration of B.cereus in open-feld-grown lettuce was signifcantly higher than that in greenhouse-grown lettuce(P<0.05).No signifcant differences were observed between measured,formula-calculated,and risk assessment values in environmental samples or lettuce(P>0.05),verifying the accuracy of the risk model.Conclusion:Soil solarization,complete manure treatment,usage of mulch flms,and irrigation water quality should be considered in agricultural practices to control B.cereus concentrations in lettuce.Overall,we found that B.cereus was more abundant in open-feld-grown lettuce,and we provide a risk evaluation framework that can guide farmers and policy-makers to control B.cereus contamination in farm-to-fork lettuce chains in China.展开更多
基金supported by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2019ZT08G315)the National Natural Science Foundation of China(52304091,52004162 and 52274089)+1 种基金the Research Project of Education Department of Hunan Province(22B0427)the China postdoctoral science foundation(2023M741047).
文摘The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic tensile responses and asso-ciated uncertainty of rock mass.At first,the particle-based model was used synthesize the intact rock and split Hopkinson pressure bar(SHPB)system,while the fractures were represented using the smooth fracture model(SJM).Subsequently,the samples of the fractured rock mass with varying joint geometrical configurations were conducted the dynamic tensile test using the numerical SHPB system.The simulated results demonstrate a gradual decrease in dynamic tensile strength(TS)with increasing fracture intensity and fracture length,which can be effectively described by nonlinear exponential func-tions.Additionally,the fracture orientation significantly influences the dynamic TS,however,the anisotropic characteristics gradually diminish as the deviation angle approaches 90°.Furthermore,as fracture intensity and fracture length increase,the dynamic TS variability also rises steadily.However,no noticeable pattern is seen when considering cases with varying fracture orientations.When subjected to SHPB loading,the fractured rock mass primarily exhibits a combined tensile-shear failure mode,contrasting with the pure tensile failure mode exhibited by the intact rock.These findings contribute signifi-cantly to comprehending the dynamic tensile responses of the fractured rock mass and can further enhance the stability analysis of in-situ rock engineering.
基金supported by the National Science Fund for Distinguished Young Scholars(52225403)the National Natural Science Foundation of China(42077244).
文摘The study of the mechanical property and damage state of coal materials under compression is a fundamental area of research in underground mining engineering.Drawing upon the compaction effect and linear energy dissipation(LED)law,a novel compressive damage constitutive model for brittle coal is proposed.Utilizing the energy-defined damage method for mate-rials,the LED law is innovatively introduced to accurately characterize the energy dissipation during the loading process,and a novel formula for characterizing the damage variable of brittle coal is proposed.On this basis,considering that the constitutive model based on the hypothesis of strain equivalence is incapable of accurately describing the compaction effect exhibited by coal material during the compression process,a correction coefficient is proposed and apply it in the novel damage constitutive model.The established conventional monotone loading and single-cyclic loading-unloading uniaxial compression damage constitutive models have been validated using experimental data from cylindrical and cuboid coal specimens.In addition,compared with the constitutive model obtained via the traditional energy calculation method based on the hypothesis that the unloading curve is a straight line,the constitutive model employing LED law can describe the stress-strain state of brittle coal more precisely.This approach introduces a new perspective and enhances the convenience for constructing the constitutive model based on energy theory.
基金supported by the National Natural Science Foundation of China(Grant Nos.22261142666,52372225,52172237,22305191,21975205)the Science,Technology,and Innovation Commission of Shenzhen Municipality(Grant No.GJHZ20220913143204008)+1 种基金the Shaanxi Science Fund for Distinguished Young Scholars(Grant No.2022JC-21)Open Project of State Key Laboratory of Supramolecular Structure and Materials(Grant No.sklssm2022022).
文摘Small-molecule ionic liquids(ILs)are frequently employed as efficient bulk phase modifiers for perovskite materials.However,their inherent characteristics,such as high volatility and ion migration properties,pose challenges in addressing the stability issues associated with perovskite solar cells(PSCs).In this study,we design a poly(IL)with multiple active sites,named poly[4-styrenesulfonyl(trifluoromethylsulfonyl)imide]pyri-dine(P[STFSI][PPyri]),as an efficient additive of perovskite materials.The S=O in the sulfonyl group chelates with uncoordinated Pb^(2+)and forms hydrogen bonds with the organic cations in the perovskite,suppressing the volatilization of the organic cations.The N+in pyridine can fix halide ions through electrostatic interaction with I-and Br-ions to prevent halide ion migration.P[STFSI][PPyri]demonstrates the ability to passivate defects and suppress nonradiative recombination in PSCs.Additionally,it facilitates the fixation of organic and halide ions,thereby enhancing the device’s stability and photoelectric performance.Consequently,the introduction of P[STFSI][PPyri]as a dopant in the devices resulted in an excellent efficiency of 24.62%,demonstrating outstanding long-term operational stability,with the encapsulated device maintaining 87.6%of its initial effi-ciency even after 1500 h of continuous maximum power point tracking.This strategy highlights the promising potential of poly(IL)as an effective additive for PSCs,providing a combination of high performance and stabil-ity.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(2022A1515011997)the Li Ka Shing Foundation Cross-Disciplinary Research Project(2020LKSFG09A)+2 种基金the Open Foundation of Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Materials(2022GXYSOF14)K.X.is thankful for the financial support from the National Natural Science Foundation of China(52203343)the Shenzhen Science and Technology Program(20210607151625001).
文摘Endowing metal halide hybrids(MHHs)with time-resolved emission and afterglow could significantly broaden their applications in fields such as information security and anti-counterfeiting.Nonetheless,there have been relatively few successes in developing organic cations with persistent room-temperature phosphorescence(RTP)to construct MHHs with afterglow.In this work,we synthesize a new polyazole,3,5-di(1H-pyrazol-4-yl)-4H-1,2,4-triazol-4-amine(DPTA),with green persistent RTP up to 1.5 s.The afterglow of DPTA reaches up to∼1.0 s even after being assembled into 0D(DPTAH_(3))InCl_(6)·2.5H_(2)O(DIC).Due to strong overlap between the triplet emission of DPTA and ^(1)S0→^(3)Px absorption of Sb^(3+),efficient triplet energy transfer(TET)with the highest yield of 65.3%and a near-unity photoluminescence quantum yield(PLQY)is achieved.More importantly,the afterglow persistence time of DIC:x%Sb can be easily tailored through Sb^(3+)doping.Given the Sb^(3+)-dependent emission color and long persistence time,a series of DIC:x%Sb are successfully utilized to demonstrate high-security-level anti-counterfeiting application.This work shows an effective strategy for designing new MHHs with tunable emission and afterglow persistence time.
基金The ELI-ALPS project(GINOP-2.3.6-15-2015-00001)is supported by the European Unionco-financed by the European Regional Development Fund
文摘The ELI ERIC facility offers international users ultrashort laser sources via the ALPS facility focusing on few-cycle laser drivers for attosecond pulses,particle beams and ultrahigh intensity interactions.The HR1 system supports attosecond high harmonic generation(HHG)and time-resolved spectroscopy at 100 kHz.However,its high repetition rate,while aiding statistical analysis,poses thermal challenges and limits certain applications requiring lower repetition rates.To address this,the HR Alignment laser system was developed for the HHG beamline at the ELI-ALPS facility.This new system delivers sub-6 fs,1 mJ pulses with a tunable repetition rate(from 10 Hz to 10 kHz)and carrier-envelope phase(CEP)stabilization.It utilizes an ytterbium-doped potassium gadolinium tungstate front-end,multi-pass cell compression,and chirped mirrors.Characterization confirms excellent energy and CEP stability(below 300 mrad),beam quality and temporal contrast,matching the HR1 laser's performance.This compact,stable system provides highflux attosecond generation for reaction microscopy enhancing ultrafast research in the ELI-ALPS facility.
基金supported by the National Natural Science Foundation of China(32400116 to L.X,82341085 to X.X.,32170189,32241021 and 32361163669 to J.H.)the National Key R&D Program of China(2021YFA1300903 to X.X.)+6 种基金Major Project of Guangzhou National Laboratory(GZNL2024A01010 to X.C.and P.G.)R&D Program of Guangzhou National Laboratory(SRPG22-002 to X.X.and SRPG22-003 to J.H)Young Doctoral Starting Sail Project of the Guangzhou Municipal Science and Technology Bureau(2025A04J4625 to L.X.)Guangdong Basic and Applied Basic Research Foundation(2021A1515011289 to X.X.)Basic Research Project of Guangzhou Institutes of Biomedicine and Health,Chinese Academy of Sciences(GIBHBRP24-02 to X.X.)Science and Technology Planning Project of Guangdong Province,China(2023B1212060050 and 2023B1212120009 to X.X.and J.H.)Start-up grants from the Chinese Academy of Sciences.
文摘Nipah virus(NiV) and related viruses form a distinct henipavirus genus within the Paramyxoviridae family. NiV continues to spillover into the humans causing deadly outbreaks with increasing human-bat interaction. NiV encodes the large protein(L) and phosphoprotein(P) to form the viral RNA polymerase machinery. Their sequences show limited homologies to those of non-henipavirus paramyxoviruses. We report two cryo-electron microscopy(cryo-EM) structures of the Nipah virus(NiV) polymerase L-P complex, expressed and purified in either its full-length or truncated form. The structures resolve the RNA-dependent RNA polymerase(RdRp) and polyribonucleotidyl transferase(PRNTase) domains of the L protein, as well as a tetrameric P protein bundle bound to the L-RdRp domain. L-protein C-terminal regions are unresolved, indicating flexibility. Two PRNTase domain zinc-binding sites, conserved in most Mononegavirales, are confirmed essential for NiV polymerase activity. The structures further reveal anchoring of the P protein bundle and P protein X domain(XD) linkers on L, via an interaction pattern distinct among Paramyxoviridae. These interactions facilitate binding of a P protein XD linker in the nucleotide entry channel and distinct positioning of other XD linkers. We show that the disruption of the L-P interactions reduces NiV polymerase activity. The reported structures should facilitate rational antiviral-drug discovery and provide a guide for the functional study of NiV polymerase.
基金This study was funded by Sina Trauma and Surgery Research Center under the project of National Trauma Registry of Iran(NTRI).The contract number was 97-03-38-40539.
文摘Purpose:Injuries are one of the leading causes of death and lead to a high social and financial burden.Injury patterns can vary significantly among different age groups and body regions.This study aimed to evaluate the relationship between mechanism of injury,patient comorbidities and severity of injuries.Methods:The study included trauma patients from July 2016 to June 2018,who were admitted to Sina Hospital,Tehran,Iran.The inclusion criteria were all injured patients who had at least one of the following:hospital length of stay more than 24 h,death in hospital,and transfer from the intensive care unit of another hospital.Data collection was performed using the National Trauma Registry of Iran minimum dataset.Results:The most common injury mechanism was road traffic injuries(49.0%),followed by falls(25.5%).The mean age of those who fell was significantly higher in comparison with other mechanisms(p<0.001).Severe extremity injuries occurred more often in the fall group than in the vehicle collision group(69.0%vs.43.5%,p<0.001).Moreover,cases of severe multiple trauma were higher amongst vehicle collisions than injuries caused by falls(27.8%vs.12.9%,p=0.003).Conclusion:Comparing falls with motor vehicle collisions,patients who fell were older and sustained more extremity injuries.Patients injured by motor vehicle collision were more likely to have sustained multiple trauma than those presenting with falls.Recognition of the relationship between mechanisms and consequences of injuries may lead to more effective interventions.
基金supported by the Shanghai Agriculture Applied Technology Development Program,China(No.X20210302)the Shanghai Sailing Program(No.22YF1440800)+1 种基金the Special Project of Agriculture Produce Quality Safety Risk Assessment(Nos.GJFP2019005 and GJFP20220205)from the Ministry of Agriculture the Rural Affairs of the People’s Republic of China,and the Applied Basic Research Project of Shanghai Academy of Agricultural Sciences(CN)(No.202309).
文摘Objectives:Bacillus cereus isolates from vegetables can cause diarrheal syndrome food poisoning.Lettuce,the most highly consumed readyto-eat vegetable,poses a signifcant risk of B.cereus exposure.Hence,B.cereus monitoring and evaluation during cultivation are essential for preventing foodborne illnesses caused by this food-pathogen combination.However,the impact of different cultivation practices on B.cereus contamination in lettuce currently remains unclear.Furthermore,a validity indicator for the experimental models cannot be effectively validated under feld conditions.Materials and Methods:Herein,we assessed the risk of B.cereus exposure using lettuce grown under two different cultivation farming systems in China(open-feld versus greenhouse)using a quantitative microbial risk assessment model.Tukey’s mean comparison method and kernel density estimation frequency distribution statistics were used for model validation using environmental samples and lettuce.Results:The mean concentration of B.cereus in open-feld-grown lettuce was signifcantly higher than that in greenhouse-grown lettuce(P<0.05).No signifcant differences were observed between measured,formula-calculated,and risk assessment values in environmental samples or lettuce(P>0.05),verifying the accuracy of the risk model.Conclusion:Soil solarization,complete manure treatment,usage of mulch flms,and irrigation water quality should be considered in agricultural practices to control B.cereus concentrations in lettuce.Overall,we found that B.cereus was more abundant in open-feld-grown lettuce,and we provide a risk evaluation framework that can guide farmers and policy-makers to control B.cereus contamination in farm-to-fork lettuce chains in China.
