The tumormicroenvironment is a complex and heterogeneous milieu characterized by the interaction between diverse cellular and non-cellular constituents.This intricate ecosystem,intrinsic to gastrointestinal(GI)cancers...The tumormicroenvironment is a complex and heterogeneous milieu characterized by the interaction between diverse cellular and non-cellular constituents.This intricate ecosystem,intrinsic to gastrointestinal(GI)cancers,encompasses elements such as the local microbiome,specific species like Helicobacter pylori,distinct immune cell subsets,and stromal cell components.The interplay between these components intricately contributes to the modulation of tumor progressiondynamicsand shapes the responses ofGI neoplasms to therapeutic interventions.A comprehensive understanding of these nuanced interactions is pivotal to elucidate the underlying complexities of GI cancers,thereby providing avenues for the strategicmanipulation of these networks,leading tomore efficacious therapeutic strategies.展开更多
Transforming growth factor beta(TGF-β)signalling has become an attractive therapeutic target due to its pro-tumorigenic actions on epithelial cells and its immunosuppressive effects in the tumour microenvironment.In ...Transforming growth factor beta(TGF-β)signalling has become an attractive therapeutic target due to its pro-tumorigenic actions on epithelial cells and its immunosuppressive effects in the tumour microenvironment.In intrahepatic cholangiocarcinoma(iCCA),a highly aggressive malignancy of the biliary tract with poor prognosis,the latest clinical trials using TGF-βinhibitors have failed indicating that the specific actions carried out by TGF-βin iCCA are yet not well delineated.Here,we show that TGF-βsignalling is highly active in iCCA and exerts a prominent suppressor effect on tumour cell lines and organoids established from iCCA metastases biopsies,that relies on a functional canonical SMAD2/3/4 signalling.Thus,TGF-βinhibitors promote,instead of inhibiting,tumour cell growth.In this context,a promising strategy is to target intracellular proteins downstream the TGF-βreceptors accounting only for TGF-βpro-tumorigenic actions.NADPH oxidase 4(NOX4),a downstream mediator of the TGF-βsignalling pathway,is strictly expressed in cancer-associated fibroblasts(CAF)of iCCA and acts in concert with NOX1 to regulate CAF functions.Use of a dual NOX4/NOX1 inhibitor impaired CAF actions and reduced tumour growth in vitro and in two different in vivo iCCA experimental models.Collectively,our findings reveal an actionable way to specifically target TGF-βpro-tumorigenic actions in CAF from iCCA without undesirable side effects on tumour cells,suggesting a potentially bright future for dual NOX4/NOX1 inhibitors in the clinics,alone or in combination with other therapies.展开更多
Over the last few years,researches in iridates have developed into an exciting field with the discovery of numerous emergent phenomena,interesting physics,and intriguing functionalities.Among the studies,iridate-based...Over the last few years,researches in iridates have developed into an exciting field with the discovery of numerous emergent phenomena,interesting physics,and intriguing functionalities.Among the studies,iridate-based artificial structures play a crucial role owing to their extreme flexibility and tunability in lattice symmetry,chemical composition,and crystal dimensionality.In this article,we present an overview of the recent progress regarding iridate-based artificial structures.We first explicitly introduce several essential concepts in iridates.Then,we illustrate important findings on representative SrIrO_(3)/SrTiO_(3) superlattices,heterostructures comprised of SrIrO3 and magnetic oxides,and their response to external electric-field stimuli.Finally,we comment on existing problems and promising future directions in this exciting field.展开更多
针对散煤输送过程中煤料均存在湿润的问题,为研究不同含水率下湿煤料对螺旋输送机磨损的影响,以不同含水率湿煤颗粒为研究对象,通过仿真和试验研究了不同含水率下设备的磨损,采用Hertz-Mindlin with JKR模型分析颗粒表面张力和黏性,并...针对散煤输送过程中煤料均存在湿润的问题,为研究不同含水率下湿煤料对螺旋输送机磨损的影响,以不同含水率湿煤颗粒为研究对象,通过仿真和试验研究了不同含水率下设备的磨损,采用Hertz-Mindlin with JKR模型分析颗粒表面张力和黏性,并通过试验机对不同含水率下湿煤料对设备磨损进行试验验证。结果表明:设备磨损量均随着含水率的增大先增加后减小,仿真实验中当JKR为40时磨损量最大;试验机测试中煤料含水率为10%时磨损量最大,含水率为20%时磨损量最小。展开更多
Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protect...Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protection,such as temperature-responsive electrodes,and thermal-shutdown separators,these methods only provide irreversible protection.Recently,reversible temperature-sensitive electrolytes have emerged as promising alternatives,offering both thermo-reversibility and self-protective properties.However,further research is crucial to fully understand these thermal-shutdown electrolytes.In this study,we propose lower critical solution temperature(LCST)phase behavior poly(benzyl methacrylate)/imidazolium-based ionic liquid mixtures to prepare temperature-sensitive electrolytes that provide reversible thermal shutdown protection of batteries.This electrolyte features an appropriate protection temperature(~105℃)and responds quickly within a 1 min at 105℃,causing cells to hardly discharge as the voltage suddenly drops to 3.38 V,and providing efficient thermal shutdown protection within 30 min.Upon cooling back to room temperature,the battery regains its original performance.Additionally,the electrolyte exhibits excellent cycling stability with the capacity retention of the battery is 91.6%after 500 cycles.This work provides a viable solution for preventing batteries from thermal runaway triggered by overheating.展开更多
To address challenges related to the intermittency of renewable energy sources,aqueous potassium-ion batteries(AKIBs)are a promising and sustainable alternative to conventional systems for large-scale energy storage.T...To address challenges related to the intermittency of renewable energy sources,aqueous potassium-ion batteries(AKIBs)are a promising and sustainable alternative to conventional systems for large-scale energy storage.To enable their practical application,maximizing energy density and longevity while minimizing production and material costs is a key goal.In this work,we propose an AKIB consisting only of abundant and cost-efficient materials,which delivers a high energy density of more than 70 Wh kg^(-1).We combine simple strategies to stabilize the Mn-rich Prussian blue analog cathode by Fe-doping,improving the crystallinity,and tuning the electrolyte composition without employing expensive water-in-salt electrolytes.Using a mixed 2.5 M Ca(NO_(3))_(2)+1.5 M KNO_(3)electrolyte,we assemble a novel AKIB with a Fe-doped manganese hexacyanoferrate cathode and an organic poly(naphthalene-4-formylethylenediamine)anode.Besides a high energy density,the full cell delivers a specific capacity of approximately 60 mAhg^(-1),a power density of 5000 W kg^(-1),and 80% capacity retention after 600 cycles.展开更多
Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimatio...Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimation is essential for understanding ecosystem functioning and informing forest management strategies to mitigate climate change.However,integrating neighborhood competition into biomass estimation models,particularly for young mixed forest stands,remains unexplored.In this study,we examined how incorporating neighborhood competition improves biomass prediction accuracy and how the influence of neighborhood competition differs between Scots pine(Pinus sylvestris L.)and Pyrenean oak(Quercus pyrenaica Willd.),as well as the relative contributions of intra-and interspecific competition to AGB.Our findings revealed that including neighborhood competition alongside tree size variables(DBH and total tree height)significantly improved the predictive accuracy of AGB models for Scots pine.This addition reduced the root mean square error(RMSE)by 14% and improved the model efficiency factor(MEF)by 15%.Furthermore,intraspecific competition in Scots pine slightly reduced AGB,whereas interspecific competition had a significant negative effect on AGB.In contrast,DBH alone was the best predictor of AGB for Pyrenean oak,as neighborhood competition did not improve model performance.Also,intra-and interspecific competition in Pyrenean oak had positive but nonsignificant effects on AGB.These findings highlight the important role of competition in biomass models and suggest species-specific approaches in competition dynamics to inform sustainable forest management and climate change adaptation strategies.展开更多
With the exponential growth of the internet of things,artificial intelligence,and energy-efficient high-volume data digital communications,there is an urgent demand to develop new information technologies with high st...With the exponential growth of the internet of things,artificial intelligence,and energy-efficient high-volume data digital communications,there is an urgent demand to develop new information technologies with high storage capacity.This needs to address the looming challenge of conventional Von Neumann architecture and Moore's law bottleneck for future data-intensive computing applications.A promising remedy lies in memristors,which offer distinct advantages of scalability,rapid access times,stable data retention,low power consumption,multistate storage capability and fast operation.Among the various materials used for active layers in memristors,low dimensional perovskite semiconductors with structural diversity and superior stability exhibit great potential for next generation memristor applications,leveraging hysteresis characteristics caused by ion migration and defects.In this review the progress of low-dimensional perovskite memory devices is comprehensively summarized.The working mechanism and fundamental processes,including ion migration dynamics,charge carrier transport and electronic resistance that underlies the switching behavior of memristors are discussed.Additionally,the device parameters are analyzed with special focus on the effective methods to improve electrical performance and operational stability.Finally,the challenges and perspective on major hurdles of low-dimensional perovskite memristors in the expansive application domains are provided.展开更多
The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surfa...The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes.展开更多
This paper describes the required testing and approval procedures of new track systems operated in Europe. To begin with, test methods and performance specifications according to European Standard （EN） are outlined....This paper describes the required testing and approval procedures of new track systems operated in Europe. To begin with, test methods and performance specifications according to European Standard （EN） are outlined. These include the repeated loading test, the determination of the static and dynamic stiffness of rail pads, clamping force and longitudinal rail resistance. The fact that labor tests are unable to simulate all the conditions in situ shows that these labor tests are not sufficient for the evaluation of the long term behaviour of a new track system： a test track of sufficient length must be constructed and exposed to traffic loads. In Europe to be accredited as a new system, a new slab track system must have a trial time of more than two years, during which the features of the whole system can be recognized. In the second part of this paper, the experience of the Institute of Road, Railway and Airfield Construction of TUM concerning the measuring methods of slab track systems carrying traffic are outlined. Also the approval procedure of the new slab tracks in Germany is discussed.展开更多
Objective:To identify the biological forms,sporozoite rate and molecular characterization of the Anopheles stephensi(An.stephensi)in Hormozgan and Sistan-Baluchistan provinces,the most important malarious areas in Ira...Objective:To identify the biological forms,sporozoite rate and molecular characterization of the Anopheles stephensi(An.stephensi)in Hormozgan and Sistan-Baluchistan provinces,the most important malarious areas in Iran.Methods:Wild live An.stephensi samples were collected from different malarious areas in southern Iran.The biological forms were identified based on number of egg-ridges.Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II(mtDNA-COI/COII).The Plasmodium infection was examined in the wild female specimens by species-specific nested-PCR method.Results:Results showed that all three biological forms including mysorensis,intermediate and type are present in the study areas.Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples.Conclusions:Presence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations.Lack of malaria parasite infection in An,stephensi,the most important vector of malaria,may be partly due to the success and achievement of ongoing active malaria control program in the region.展开更多
AIM:To compare frontalis sling and tarsoconjunctival mullerectomy plus levator resection(TCMLR)in subjects with severe unilateral congenital ptosis with poor levator function(LF).METHODS:A prospective non-randomized n...AIM:To compare frontalis sling and tarsoconjunctival mullerectomy plus levator resection(TCMLR)in subjects with severe unilateral congenital ptosis with poor levator function(LF).METHODS:A prospective non-randomized nonblinded single center clinical trial.Fifty patients with severe unilateral congenital ptosis with poor LF were recruited.The frontalis sling and TCMLR were performed and the functional,cosmetic outcomes,complications,and success rate were evaluated at 1,3,and 6mo postoperatively.The t-test,Chi-square,Fishers exact,and nonparametric MannWhitney tests were used by SPSS software.RESULTS:Frontalis sling and TCMLR procedures were performed on 26 and 24 patients respectively.The mean age was 10.97±10.67y.LF was significantly better in the TCMLR group at months 1,3,and 6(P=0.002).Lagophthalmos was more common in the TCMLR group(no significant difference).At month 3,mild punctate epithelial erosions were observed more in the frontalis sling group(P=0.002).Significant complete success rate of 1st and 6th month for the frontalis sling vs TCMLR groups were 50%vs 20.8%(P=0.02),and 38.4%vs 50%(P=0.03)respectively.CONCLUSION:Complete success rate of TCMLR is higher in long-term follow-up in contrast with the frontalis sling in the short-term.Transient complications are more detected in mid-term follow-ups in both groups.展开更多
文摘The tumormicroenvironment is a complex and heterogeneous milieu characterized by the interaction between diverse cellular and non-cellular constituents.This intricate ecosystem,intrinsic to gastrointestinal(GI)cancers,encompasses elements such as the local microbiome,specific species like Helicobacter pylori,distinct immune cell subsets,and stromal cell components.The interplay between these components intricately contributes to the modulation of tumor progressiondynamicsand shapes the responses ofGI neoplasms to therapeutic interventions.A comprehensive understanding of these nuanced interactions is pivotal to elucidate the underlying complexities of GI cancers,thereby providing avenues for the strategicmanipulation of these networks,leading tomore efficacious therapeutic strategies.
基金supported by Spanish Association for Cancer Research(AECC),Spain,grant#PRYGN211279FABR,to I.F.Agencia Estatal de Investigación(AEI),Ministry of Science and Innovation(MICIN),Spain,cofounded by FEDER funds/Development Fund—a way to build Europe,grant numbers#RTI2018-094079-B-100,#RTC2019-007125-1,to I.F.+12 种基金#PID2019-108651RJ-I00,PID2022-141984OB-I00 and RYC2021-034121-I,to J.V.J.V.funded by AEI,MICIN,through the Retos Investigación grant number PID2019-108651RJ-I00/DOI 10.13039/501100011033 and“Ramon y Cajal”program RYC2021-034121-IThe CIBEREHD,National Biomedical Research Institute on Liver and Gastrointestinal Diseases,is funded by the Instituto de Salud Carlos III,Spainsupported by Inserm,Universitéde Rennes,Ligue Contre le Cancer(R23037NN),INCa(EU TRANSCAN23-002-2023-129,INCa_18688,R21251ND)ITMO Cancer of AVIESAN within the framework of the 2021-2030 Cancer Control Strategy,on funds administered by Inserm(C18007NS,C20013NS,C20014NS)the French Ministry of Health and the French National Cancer Institute(PRT-K20-136)supported by grants from the Spanish Ministry of Science,Innovation and University(PID2019-108008RJ-I00,PID2023-146827OB-I00),FundacióLa MaratóTV3(201931-31)“Ramon y Cajal”program(RYC2020-029098-I)financial support from the“Ligue contre le cancer”(RS24/75-62)from ITMO Cancer of Aviesan on funds administered by Inserm(C21044DS/ASC21044DSA)supported by PID2021-124694OA-I00,MCIN/AEI/10.13039/501100011033FEDER Una manera de hacer Europa,The European Union grant agreement 101077312*Ramon y Cajal program RYC2022-036321-I.
文摘Transforming growth factor beta(TGF-β)signalling has become an attractive therapeutic target due to its pro-tumorigenic actions on epithelial cells and its immunosuppressive effects in the tumour microenvironment.In intrahepatic cholangiocarcinoma(iCCA),a highly aggressive malignancy of the biliary tract with poor prognosis,the latest clinical trials using TGF-βinhibitors have failed indicating that the specific actions carried out by TGF-βin iCCA are yet not well delineated.Here,we show that TGF-βsignalling is highly active in iCCA and exerts a prominent suppressor effect on tumour cell lines and organoids established from iCCA metastases biopsies,that relies on a functional canonical SMAD2/3/4 signalling.Thus,TGF-βinhibitors promote,instead of inhibiting,tumour cell growth.In this context,a promising strategy is to target intracellular proteins downstream the TGF-βreceptors accounting only for TGF-βpro-tumorigenic actions.NADPH oxidase 4(NOX4),a downstream mediator of the TGF-βsignalling pathway,is strictly expressed in cancer-associated fibroblasts(CAF)of iCCA and acts in concert with NOX1 to regulate CAF functions.Use of a dual NOX4/NOX1 inhibitor impaired CAF actions and reduced tumour growth in vitro and in two different in vivo iCCA experimental models.Collectively,our findings reveal an actionable way to specifically target TGF-βpro-tumorigenic actions in CAF from iCCA without undesirable side effects on tumour cells,suggesting a potentially bright future for dual NOX4/NOX1 inhibitors in the clinics,alone or in combination with other therapies.
基金support from the National Natural Science Foundation of China(NSFC)under grant No.51872155 and 52025024the Beijing Nature Science Foundation(Z200007)+4 种基金the Ministry of Science and Technology of China(2021YFE0107900 and 2021YFA1400300)support from the High Magnetic Field Laboratory of Anhui Province(AHHM-FX-2021-03)the NSFC under Grant No.12104460support from the NSFC under Grant No.92163113 and No.52250418support from the National Science Foundation under Grant No.DMR1848269.
文摘Over the last few years,researches in iridates have developed into an exciting field with the discovery of numerous emergent phenomena,interesting physics,and intriguing functionalities.Among the studies,iridate-based artificial structures play a crucial role owing to their extreme flexibility and tunability in lattice symmetry,chemical composition,and crystal dimensionality.In this article,we present an overview of the recent progress regarding iridate-based artificial structures.We first explicitly introduce several essential concepts in iridates.Then,we illustrate important findings on representative SrIrO_(3)/SrTiO_(3) superlattices,heterostructures comprised of SrIrO3 and magnetic oxides,and their response to external electric-field stimuli.Finally,we comment on existing problems and promising future directions in this exciting field.
文摘针对散煤输送过程中煤料均存在湿润的问题,为研究不同含水率下湿煤料对螺旋输送机磨损的影响,以不同含水率湿煤颗粒为研究对象,通过仿真和试验研究了不同含水率下设备的磨损,采用Hertz-Mindlin with JKR模型分析颗粒表面张力和黏性,并通过试验机对不同含水率下湿煤料对设备磨损进行试验验证。结果表明:设备磨损量均随着含水率的增大先增加后减小,仿真实验中当JKR为40时磨损量最大;试验机测试中煤料含水率为10%时磨损量最大,含水率为20%时磨损量最小。
基金funded by the National Natural Science Foundation of China(no.22075155)the Zhejiang Provincial Natural Science Foundation of China(No.LY24B030002)+2 种基金Ningbo Natural Science Foundation(2023J089)the China Scholarship Council(CSC)the Ningbo Science and Technology Bureau(2024QL036).
文摘Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protection,such as temperature-responsive electrodes,and thermal-shutdown separators,these methods only provide irreversible protection.Recently,reversible temperature-sensitive electrolytes have emerged as promising alternatives,offering both thermo-reversibility and self-protective properties.However,further research is crucial to fully understand these thermal-shutdown electrolytes.In this study,we propose lower critical solution temperature(LCST)phase behavior poly(benzyl methacrylate)/imidazolium-based ionic liquid mixtures to prepare temperature-sensitive electrolytes that provide reversible thermal shutdown protection of batteries.This electrolyte features an appropriate protection temperature(~105℃)and responds quickly within a 1 min at 105℃,causing cells to hardly discharge as the voltage suddenly drops to 3.38 V,and providing efficient thermal shutdown protection within 30 min.Upon cooling back to room temperature,the battery regains its original performance.Additionally,the electrolyte exhibits excellent cycling stability with the capacity retention of the battery is 91.6%after 500 cycles.This work provides a viable solution for preventing batteries from thermal runaway triggered by overheating.
基金Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy-EXC 2089/1-390776260(e-conversion)for fundingfinancial support from TUM Innovation Network for Artificial Intelligence powered Multifunctional Material Design(ARTEMIS)。
文摘To address challenges related to the intermittency of renewable energy sources,aqueous potassium-ion batteries(AKIBs)are a promising and sustainable alternative to conventional systems for large-scale energy storage.To enable their practical application,maximizing energy density and longevity while minimizing production and material costs is a key goal.In this work,we propose an AKIB consisting only of abundant and cost-efficient materials,which delivers a high energy density of more than 70 Wh kg^(-1).We combine simple strategies to stabilize the Mn-rich Prussian blue analog cathode by Fe-doping,improving the crystallinity,and tuning the electrolyte composition without employing expensive water-in-salt electrolytes.Using a mixed 2.5 M Ca(NO_(3))_(2)+1.5 M KNO_(3)electrolyte,we assemble a novel AKIB with a Fe-doped manganese hexacyanoferrate cathode and an organic poly(naphthalene-4-formylethylenediamine)anode.Besides a high energy density,the full cell delivers a specific capacity of approximately 60 mAhg^(-1),a power density of 5000 W kg^(-1),and 80% capacity retention after 600 cycles.
基金the 2019 call for the predoctoral contract at the University of Valladolid cofinanced by Banco de Santander and projects‘CLU-2019-01-Unidad de Excelencia Instituto iuFOR’,‘PID2021-126275OB-C21’and‘PID2021-126275OB-C22’-Integrated Forest Management along complexity gradients(IMFLEX)‘MCIN/AEI/10.13039/501100011033/FEDER,UE’,which received financial support from the Regional Government of Castilla and León,Spainthe European Regional Development Fund(ERDF).
文摘Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimation is essential for understanding ecosystem functioning and informing forest management strategies to mitigate climate change.However,integrating neighborhood competition into biomass estimation models,particularly for young mixed forest stands,remains unexplored.In this study,we examined how incorporating neighborhood competition improves biomass prediction accuracy and how the influence of neighborhood competition differs between Scots pine(Pinus sylvestris L.)and Pyrenean oak(Quercus pyrenaica Willd.),as well as the relative contributions of intra-and interspecific competition to AGB.Our findings revealed that including neighborhood competition alongside tree size variables(DBH and total tree height)significantly improved the predictive accuracy of AGB models for Scots pine.This addition reduced the root mean square error(RMSE)by 14% and improved the model efficiency factor(MEF)by 15%.Furthermore,intraspecific competition in Scots pine slightly reduced AGB,whereas interspecific competition had a significant negative effect on AGB.In contrast,DBH alone was the best predictor of AGB for Pyrenean oak,as neighborhood competition did not improve model performance.Also,intra-and interspecific competition in Pyrenean oak had positive but nonsignificant effects on AGB.These findings highlight the important role of competition in biomass models and suggest species-specific approaches in competition dynamics to inform sustainable forest management and climate change adaptation strategies.
基金supported by funding from the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany's Excellence Strategy-EXC 2089/1-390776260(e-conversion)via the International Research Training Group 2022 Alberta/Technical University of Munich International Graduate School for Environmentally Responsible Functional Hybrid Materials(ATUMS).
文摘With the exponential growth of the internet of things,artificial intelligence,and energy-efficient high-volume data digital communications,there is an urgent demand to develop new information technologies with high storage capacity.This needs to address the looming challenge of conventional Von Neumann architecture and Moore's law bottleneck for future data-intensive computing applications.A promising remedy lies in memristors,which offer distinct advantages of scalability,rapid access times,stable data retention,low power consumption,multistate storage capability and fast operation.Among the various materials used for active layers in memristors,low dimensional perovskite semiconductors with structural diversity and superior stability exhibit great potential for next generation memristor applications,leveraging hysteresis characteristics caused by ion migration and defects.In this review the progress of low-dimensional perovskite memory devices is comprehensively summarized.The working mechanism and fundamental processes,including ion migration dynamics,charge carrier transport and electronic resistance that underlies the switching behavior of memristors are discussed.Additionally,the device parameters are analyzed with special focus on the effective methods to improve electrical performance and operational stability.Finally,the challenges and perspective on major hurdles of low-dimensional perovskite memristors in the expansive application domains are provided.
基金the National Natural Science Foundation of China(Nos.U2032101 and 11905306)the National Key Research and Development Project of China(No.2022YFB2402602).
文摘The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes.
文摘This paper describes the required testing and approval procedures of new track systems operated in Europe. To begin with, test methods and performance specifications according to European Standard （EN） are outlined. These include the repeated loading test, the determination of the static and dynamic stiffness of rail pads, clamping force and longitudinal rail resistance. The fact that labor tests are unable to simulate all the conditions in situ shows that these labor tests are not sufficient for the evaluation of the long term behaviour of a new track system： a test track of sufficient length must be constructed and exposed to traffic loads. In Europe to be accredited as a new system, a new slab track system must have a trial time of more than two years, during which the features of the whole system can be recognized. In the second part of this paper, the experience of the Institute of Road, Railway and Airfield Construction of TUM concerning the measuring methods of slab track systems carrying traffic are outlined. Also the approval procedure of the new slab tracks in Germany is discussed.
基金financially supported by Tehran University of Medical Sciences(TUMS)(Grant No.89-01-27-10448)
文摘Objective:To identify the biological forms,sporozoite rate and molecular characterization of the Anopheles stephensi(An.stephensi)in Hormozgan and Sistan-Baluchistan provinces,the most important malarious areas in Iran.Methods:Wild live An.stephensi samples were collected from different malarious areas in southern Iran.The biological forms were identified based on number of egg-ridges.Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II(mtDNA-COI/COII).The Plasmodium infection was examined in the wild female specimens by species-specific nested-PCR method.Results:Results showed that all three biological forms including mysorensis,intermediate and type are present in the study areas.Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples.Conclusions:Presence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations.Lack of malaria parasite infection in An,stephensi,the most important vector of malaria,may be partly due to the success and achievement of ongoing active malaria control program in the region.
基金Supported by Tehran University of Medical Sciences(No.9511257008)。
文摘AIM:To compare frontalis sling and tarsoconjunctival mullerectomy plus levator resection(TCMLR)in subjects with severe unilateral congenital ptosis with poor levator function(LF).METHODS:A prospective non-randomized nonblinded single center clinical trial.Fifty patients with severe unilateral congenital ptosis with poor LF were recruited.The frontalis sling and TCMLR were performed and the functional,cosmetic outcomes,complications,and success rate were evaluated at 1,3,and 6mo postoperatively.The t-test,Chi-square,Fishers exact,and nonparametric MannWhitney tests were used by SPSS software.RESULTS:Frontalis sling and TCMLR procedures were performed on 26 and 24 patients respectively.The mean age was 10.97±10.67y.LF was significantly better in the TCMLR group at months 1,3,and 6(P=0.002).Lagophthalmos was more common in the TCMLR group(no significant difference).At month 3,mild punctate epithelial erosions were observed more in the frontalis sling group(P=0.002).Significant complete success rate of 1st and 6th month for the frontalis sling vs TCMLR groups were 50%vs 20.8%(P=0.02),and 38.4%vs 50%(P=0.03)respectively.CONCLUSION:Complete success rate of TCMLR is higher in long-term follow-up in contrast with the frontalis sling in the short-term.Transient complications are more detected in mid-term follow-ups in both groups.
