Let R_1 and R_2 be two rings with unit I. We give some characterizations of ring homomorphisms and ring isomorphisms between R_1 and R_2 in term of complete preservers of fixed points of multipliers, under some mild a...Let R_1 and R_2 be two rings with unit I. We give some characterizations of ring homomorphisms and ring isomorphisms between R_1 and R_2 in term of complete preservers of fixed points of multipliers, under some mild assumption on R_1. Applications to several kinds of operator algebras such as Banach algebras, nest algebras, matrix algebras and standard operator algebras are presented.展开更多
Suppose R is an idempotence-diagonalizable ring. Let n and m be two arbitrary positive integers with n ≥ 3. We denote by Mn（R） the ring of all n x n matrices over R. Let （Jn（R）） be the additive subgroup of Mn（...Suppose R is an idempotence-diagonalizable ring. Let n and m be two arbitrary positive integers with n ≥ 3. We denote by Mn（R） the ring of all n x n matrices over R. Let （Jn（R）） be the additive subgroup of Mn（R） generated additively by all idempotent matrices. Let JJ = （Jn（R）） or Mn（R）. We describe the additive preservers of idempotence from JJ to Mm（R） when 2 is a unit of R. Thereby, we also characterize the Jordan （respectively, ring and ring anti-） homomorphisms from Mn （R） to Mm （R） when 2 is a unit of R.展开更多
Let B（X） be the algebra of all bounded linear operators on an infinite-dimensional complex or real Banach space X. Given an integer n 〉 1, we show that an additive surjective map Ф on B（X） preserves Drazin inver...Let B（X） be the algebra of all bounded linear operators on an infinite-dimensional complex or real Banach space X. Given an integer n 〉 1, we show that an additive surjective map Ф on B（X） preserves Drazin invertible operators of index non-greater than n in both directions if and only if Ф is either of the form Ф（T） = aATA-1 or of the form Ф（T） = aBT＊B-1 where a is a non-zero scalar, A ： X → X and B ： X＊ → X are two bounded invertible linear or conjugate linear operators.展开更多
Let H be a complex Hilbert space of dimension greater than 2, and B（H） denote the Banach algebra of all bounded linear operators on H. For A, B C B（H）, define the binary relation A ≤ B by A＊A = A＊B and AA＊ = A...Let H be a complex Hilbert space of dimension greater than 2, and B（H） denote the Banach algebra of all bounded linear operators on H. For A, B C B（H）, define the binary relation A ≤ B by A＊A = A＊B and AA＊ = AB＊. Then （B（H）, ＂〈.＂） is a partially ordered set and the relation ＂≤＂ is called the star order on B（H）. Denote by Bs（H） the set of all self-adjoint operators in B（H）. In this paper, we first characterize nonlinear continuous bijective maps on Bs（H） which preserve the star order in both directions. We characterize also additive maps （or linear maps） on B（H） （or nest algebras） which are multiplicative at some invertible operator.展开更多
Chinese-German sculptor Zhou Xiaoping has been traveling between China and Germany,creating sculptures,since 2003.She has created more than 80 large,urban sculptures,each of which has become a vivid carrier of urban m...Chinese-German sculptor Zhou Xiaoping has been traveling between China and Germany,creating sculptures,since 2003.She has created more than 80 large,urban sculptures,each of which has become a vivid carrier of urban memories.During the past decade,she has focused on creating freeform sculptures,and she has launched a global,cross-disciplinary-artist-collaboration project,which has involved the preservation of archives for contemporary artistic creation.展开更多
This study addresses the risk of privacy leakage during the transmission and sharing of multimodal data in smart grid substations by proposing a three-tier privacy-preserving architecture based on asynchronous federat...This study addresses the risk of privacy leakage during the transmission and sharing of multimodal data in smart grid substations by proposing a three-tier privacy-preserving architecture based on asynchronous federated learning.The framework integrates blockchain technology,the InterPlanetary File System(IPFS)for distributed storage,and a dynamic differential privacy mechanism to achieve collaborative security across the storage,service,and federated coordination layers.It accommodates both multimodal data classification and object detection tasks,enabling the identification and localization of key targets and abnormal behaviors in substation scenarios while ensuring privacy protection.This effectively mitigates the single-point failures and model leakage issues inherent in centralized architectures.A dynamically adjustable differential privacy mechanism is introduced to allocate privacy budgets according to client contribution levels and upload frequencies,achieving a personalized balance between model performance and privacy protection.Multi-dimensional experimental evaluations,including classification accuracy,F1-score,encryption latency,and aggregation latency,verify the security and efficiency of the proposed architecture.The improved CNN model achieves 72.34%accuracy and an F1-score of 0.72 in object detection and classification tasks on infrared surveillance imagery,effectively identifying typical risk events such as not wearing safety helmets and unauthorized intrusion,while maintaining an aggregation latency of only 1.58 s and a query latency of 80.79 ms.Compared with traditional static differential privacy and centralized approaches,the proposed method demonstrates significant advantages in accuracy,latency,and security,providing a new technical paradigm for efficient,secure data sharing,object detection,and privacy preservation in smart grid substations.展开更多
Chinese abbreviations improve communicative efficiency by extracting key components from longer expressions.They are widely used in both daily communication and professional domains.However,existing abbreviation gener...Chinese abbreviations improve communicative efficiency by extracting key components from longer expressions.They are widely used in both daily communication and professional domains.However,existing abbreviation generation methods still face two major challenges.First,sequence-labeling-based approaches often neglect contextual meaning by making binary decisions at the character level,leading to abbreviations that fail to capture semantic completeness.Second,generation-basedmethods rely heavily on a single decoding process,which frequently produces correct abbreviations but ranks them lower due to inadequate semantic evaluation.To address these limitations,we propose a novel two-stage frameworkwithGeneration–Iterative Optimization forAbbreviation(GIOA).In the first stage,we design aChain-of-Thought prompting strategy and incorporate definitional and situational contexts to generate multiple abbreviation candidates.In the second stage,we introduce a Semantic Preservation Dynamic Adjustment mechanism that alternates between character-level importance estimation and semantic restoration to optimize candidate ranking.Experiments on two public benchmark datasets show that our method outperforms existing state-of-the-art approaches,achieving Hit@1 improvements of 15.15%and 13.01%,respectively,while maintaining consistent results in Hit@3.展开更多
With the rapid expansion of drone applications,accurate detection of objects in aerial imagery has become crucial for intelligent transportation,urban management,and emergency rescue missions.However,existing methods ...With the rapid expansion of drone applications,accurate detection of objects in aerial imagery has become crucial for intelligent transportation,urban management,and emergency rescue missions.However,existing methods face numerous challenges in practical deployment,including scale variation handling,feature degradation,and complex backgrounds.To address these issues,we propose Edge-enhanced and Detail-Capturing You Only Look Once(EHDC-YOLO),a novel framework for object detection in Unmanned Aerial Vehicle(UAV)imagery.Based on the You Only Look Once version 11 nano(YOLOv11n)baseline,EHDC-YOLO systematically introduces several architectural enhancements:(1)a Multi-Scale Edge Enhancement(MSEE)module that leverages multi-scale pooling and edge information to enhance boundary feature extraction;(2)an Enhanced Feature Pyramid Network(EFPN)that integrates P2-level features with Cross Stage Partial(CSP)structures and OmniKernel convolutions for better fine-grained representation;and(3)Dynamic Head(DyHead)with multi-dimensional attention mechanisms for enhanced cross-scale modeling and perspective adaptability.Comprehensive experiments on the Vision meets Drones for Detection(VisDrone-DET)2019 dataset demonstrate that EHDC-YOLO achieves significant improvements,increasing mean Average Precision(mAP)@0.5 from 33.2%to 46.1%(an absolute improvement of 12.9 percentage points)and mAP@0.5:0.95 from 19.5%to 28.0%(an absolute improvement of 8.5 percentage points)compared with the YOLOv11n baseline,while maintaining a reasonable parameter count(2.81 M vs the baseline’s 2.58 M).Further ablation studies confirm the effectiveness of each proposed component,while visualization results highlight EHDC-YOLO’s superior performance in detecting objects and handling occlusions in complex drone scenarios.展开更多
Background:Ex vivo lung perfusion(EVLP)has emerged as a critical technique for lung preservation and evaluation prior to transplantation.While conventional rat EVLP systems utilize closed-loop dual cannulation of pulm...Background:Ex vivo lung perfusion(EVLP)has emerged as a critical technique for lung preservation and evaluation prior to transplantation.While conventional rat EVLP systems utilize closed-loop dual cannulation of pulmonary artery(PA)and vein,the effect of the simplified model using single PA cannulation with passive venous drainage is unknown.Methods:We developed two EVLP models in rats:a semi-closed circuit with PA-only cannulation and left atrial incision for passive venous drainage(SC-EVLP),and a closed circuit employing both arterial and venous cannulation(C-EVLP).Donor lungs were perfused for a defined duration and subsequently orthotopically transplanted.We evaluated pulmonary function parameters,histopathological injury scores,inflammatory cytokine levels,and apoptotic marker expression at the end of perfusion and posttransplantation.Results:Compared to the conventional EVLP,the SC-EVLP group exhibited significantly lower PA pressure and improved dynamic lung compliance throughout perfusion.Although the levels of tumor necrosis factor-αin the perfusate were higher in the SC-EVLP group,other cytokine levels in the perfusate and bronchoalveolar lavage fluid exhibited no significant differences.Pulmonary edema was reduced in the SC-EVLP group,as indicated by a lower lung wet-to-dry ratio.After transplantation,lungs from the SC-EVLP group exhibited lower histological injury scores,reduced apoptosis,and decreased serum cytokine levels,suggesting attenuated inflammation and tissue damage.Conclusions:In a rat model,single PA cannulation with passive venous drainage reduced pulmonary edema during EVLP and reduced lung injury and systemic inflammation after transplantation.展开更多
The Nuo mask is the core visual vehicle within China’s Nuo culture and constitutes a complex symbolic system through facial features(icons),patterns(indexes),and colors(symbols).Within the context of intangible cultu...The Nuo mask is the core visual vehicle within China’s Nuo culture and constitutes a complex symbolic system through facial features(icons),patterns(indexes),and colors(symbols).Within the context of intangible cultural heritage(ICH)preservation,its value lies in the continuation and revitalization of its dynamic symbolic functions.Grounded in semiotic theory,this paper elaborates on three core dimensions of symbolic value manifested by Nuo masks in ICH preservation:a ritual symbol for living transmission,a symbol of identity for collective memory,and an aesthetic symbol as a source of creativity.展开更多
Background:Locally advanced laryngeal squamous cell carcinoma(LA-LSCC)presents clinical challenges due to the lack of reliable non-invasive biomarkers.This study aimed to evaluate miR-449a as a diagnostic and prognost...Background:Locally advanced laryngeal squamous cell carcinoma(LA-LSCC)presents clinical challenges due to the lack of reliable non-invasive biomarkers.This study aimed to evaluate miR-449a as a diagnostic and prognostic biomarker in LA-LSCC.Methods:miR-449a expression was analyzed in tumor tissues,adjacent normal tissues,and serum from 81 LA-LSCC patients and 50 controls using quantitative real-time reverse transcription polymerase chain reaction(qRT-PCR).We assessed the diagnostic accuracy by Receiver Operating Characteristic curve(ROC curves),clinicopathological associations,survival outcomes(Kaplan-Meier),and treatment response dynamics.Results:miR-449a was significantly downregulated in LA-LSCC tissues(p<0.0001)and serum(p<0.0001),with a strong tissue-serum correlation(R^(2)=0.988).Tissue miR-449a demonstrated a diagnostic accuracy(Area Under the Curve,AUC=0.857),while serum showed moderate accuracy(AUC=0.734).High miR-449a expression correlated with favorable clinicopathological features and improved survival(median overall survival:67.82 vs.23.74 months;p=0.0012).Multivariate analysis confirmed miR-449a as an independent prognostic factor(p<0.001).miR-449a levels increased post-treatment,particularly in responders to chemotherapy/radiation(p<0.0001).Conclusion:miR-449a serves as a non-invasive biomarker for LA-LSCC diagnosis,prognosis,and treatment monitoring.Its dynamic expression highlights potential for risk stratification and therapy response prediction,warranting further validation in larger cohorts.展开更多
Instrument separation is a critical complication during root canal therapy,impacting treatment success and long-term tooth preservation.The etiology of instrument separation is multifactorial,involving the intricate a...Instrument separation is a critical complication during root canal therapy,impacting treatment success and long-term tooth preservation.The etiology of instrument separation is multifactorial,involving the intricate anatomy of the root canal system,instrument-related factors,and instrumentation techniques.Instrument separation can hinder thorough cleaning,shaping,and obturation of the root canal,posing challenges to successful treatment outcomes.Although retrieval of separated instrument is often feasible,it carries risks including perforation,excessive removal of tooth structure and root fractures.Effective management of separated instruments requires a comprehensive understanding of the contributing factors,meticulous preoperative assessment,and precise evaluation of the retrieval difficulty.The application of appropriate retrieval techniques is essential to minimize complications and optimize clinical outcomes.The current manuscript provides a framework for understanding the causes,risk factors,and clinical management principles of instrument separation.By integrating effective strategies,endodontists can enhance decision-making,improve endodontic treatment success and ensure the preservation of natural dentition.展开更多
In addition to the organic matter type,abundance,thermal maturity,and shale reservoir space,the preservation conditions of source rocks play a key factor in affecting the quantity and quality of retained hydrocarbons ...In addition to the organic matter type,abundance,thermal maturity,and shale reservoir space,the preservation conditions of source rocks play a key factor in affecting the quantity and quality of retained hydrocarbons in source rocks of lacustrine shale,yet this aspect has received little attention.This paper,based on the case analysis,explores how preservation conditions influence the enrichment of mobile hydrocarbons in shale oil.Research showns that good preservation conditions play three key roles.(1)Ensure the retention of sufficient light hydrocarbons(C_(1)–C_(13)),medium hydrocarbons(C_(14)–C_(25))and small molecular aromatics(including 1–2 benzene rings)in the formation,which enhances the fluidity and flow of shale oil;(2)Maintain a high energy field(abnormally high pressure),thus facilitating the maximum outflow of shale oil;(3)Ensure that the retained hydrocarbons have the miscible flow condition of multi-component hydrocarbons(light hydrocarbons,medium hydrocarbons,heavy hydrocarbons,and heteroatomic compounds),so that the heavy hydrocarbons(C_(25+))and heavy components(non-hydrocarbons and asphaltenes)have improved fluidity and maximum flow capacity.In conclusion,in addition to the advantages of organic matter type,abundance,thermal maturity,and reservoir space,good preservation conditions of shale layers are essential for the formation of economically viable shale oil reservoirs,which should be incorporated into the evaluation criteria of shale oil-rich areas/segments and considered a necessary factor when selecting favorable exploration targets.展开更多
The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model.To address the limitations of traditional methods in obtaining high-quality se...The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model.To address the limitations of traditional methods in obtaining high-quality sediment,a novel sampling system with 6000 m operational capability and three-month endurance was developed.It is equipped with three sediment samplers,a set of formaldehyde preservation solution injection devices.The system is controlled by a low-power,timing-triggered controllers.To investigate low-disturbance rheological mechanisms,gap controlled rheological tests were conducted to optimize the structural design of the sampling and sealing assembly.Stress-controlled shear rheological tests were employed to investigate the mechanisms governing yield stress in sediments under varying temperature conditions and boundary roughness.Additionally,the coupled Eulerian-Lagrangian(CEL)method and sediment rheological constitutive models were employed to simulate tube-soil interaction dynamics and sediment disturbance.The radial heterogeneity of sediment disturbance and friction variation of the sampling tube were revealed.The tube was completely“plugged”at a penetration depth of 261 mm,providing critical data support to the penetration depth parameters.The deep-sea pressure test and South China Sea field trials demonstrated the system’s capability to collect and preserve quantitative time-series sediment samples with high fidelity.展开更多
Occurrence and abundance of molecular hydrogen in natural geologic reservoirs are enigmatic,due to its various sources,diverse migration pathways and complicated biological and chemical reactions.Natural gas samples c...Occurrence and abundance of molecular hydrogen in natural geologic reservoirs are enigmatic,due to its various sources,diverse migration pathways and complicated biological and chemical reactions.Natural gas samples containing hydrogen from producing wells in several sedimentary basins in China were collected in this study,and gas abundances and isotopic compositions of these gases were compared with those in global petroliferous basins and deep intrusive rocks.Several geochemical indicators were suggested for identifying sources,migration and accumulation mechanisms of hydrogen in the subsurface environment.Hydrogen contents in natural gas deposits have contributions from various sources with the following high-to-low order:microbial degradation>serpentinization>deep mantle volatile release>radiation-induced water decomposition>thermal cracking of organic matter.A hydrogen-rich reservoir in Kansas,USA,is specifically analyzed to determine its formation mechanism.This study suggests that future exploration of geological hydrogen resources may focus on the igneous rock bodies with overlying dense sedimentary rocks in the continental rift systems.展开更多
The heritage preservation is of great intractability to the conservators as each kind of heritage material has unique and diverse requirements on temperature,humidity and air cleanliness.It is promising for metal-orga...The heritage preservation is of great intractability to the conservators as each kind of heritage material has unique and diverse requirements on temperature,humidity and air cleanliness.It is promising for metal-organic frameworks(MOFs),the multifunctional environment remediation materials,to be applied in heritage environmental protection.The advantages of MOFs lie in their multifunction like adsorption,photocatalysis,sterilization,as well as the controllable structure and properties that could be flexibly adjusted as demands,helping the heritage against various environmental threats.Thereby,the applications and the corresponding mechanisms of MOFs in cultural heritage preservation were reviewed in this work,including harmful gas adsorption,surface waterproofing,particulate matters(PM)removal,anti-bacterial and humidity control of environment.Finally,the selection principles and precautions of MOFs in heritage preservation were discussed,aiming to provide a forward-looking direction for the selection and application of MOFs.展开更多
To address the challenges in studying the pore formation and evolution processes,and unclear preservation mechanisms of deep to ultra-deep carbonate rocks,a high-temperature and high-pressure visualization simulation ...To address the challenges in studying the pore formation and evolution processes,and unclear preservation mechanisms of deep to ultra-deep carbonate rocks,a high-temperature and high-pressure visualization simulation experimental device was developed for ultra-deep carbonate reservoirs.Carbonate rock samples from the Sichuan Basin and Tarim Basin were used to simulate the dissolution-precipitation process of deep to ultra-deep carbonate reservoirs in an analogous geological setting.This unit comprises four core modules:an ultra-high temperature,high pressure triaxial stress core holder module(temperature higher than 300°C,pressure higher than 150 MPa),a multi-stage continuous flow module with temperature-pressure regulation,an ultra-high temperature-pressure sapphire window cell and an in-situ high-temperature-pressure fluid property measurement module and real-time ultra-high temperature-pressure permeability detection module.The new experimental device was used for simulation experiment,the geological insights were obtained in three aspects.First,the pore-throat structure of carbonate is controlled by lithology and initial pore-throat structure,and fluid type,concentration and dissolution duration determine the degree of dissolution.The dissolution process exhibits two evolution patterns.The dissolution scale is positively correlated to the temperature and pressure,and the pore-forming peak period aligns well with the hydrocarbon generation peak period.Second,the dissolution potential of dolomite in an open flow system is greater than that of limestone,and secondary dissolved pores formed continuously are controlled by the type and concentration of acidic fluids and the initial physical properties.These pores predominantly distribute along pre-existing pore/fracture zones.Third,in a nearly closed diagenetic system,after the chemical reaction between acidic fluids and carbonate rock reaches saturation and dynamic equilibrium,the pore structure no longer changes,keeping pre-existing pores well-preserved.These findings have important guiding significance for the evaluation of pore-throat structure and development potential of deep to ultra-deep carbonate reservoirs,and the prediction of main controlling factors and distribution of high-quality carbonate reservoirs.展开更多
The umbrella term"neurodege ne rative disorders"(NDDs) refers to several conditions characterized by a progressive loss of structure and function of cells belonging to the nervous system.Such diseases affect...The umbrella term"neurodege ne rative disorders"(NDDs) refers to several conditions characterized by a progressive loss of structure and function of cells belonging to the nervous system.Such diseases affect more than 50million people worldwide.Neurodegenerative disorders are characterized by sundry factors and pathophysiological mechanisms that a re challenging to be fully profiled.Many of these rely on cell signaling pathways to preserve homeostasis,involving second messengers such as cyclic adenosine monophosphate (cAMP)and cyclic guanosine 3',5'-monophosphate(cGMP).Their ability to control the duration and amplitude of the signaling cascade is given by the presence of several common and uncommon effectors.Protein kinases A and G (PKA and PKG),phosphodiesterases (PDEs),and scaffold proteins are among them.展开更多
In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were inve...In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.展开更多
To alleviate the quality deterioration and extend the shelf life of crucian carp fillets,a bio-based active composite film integrating eugenol(EG)-loaded mesoporous silica nanoparticles(MSNs)modified with caffeic acid...To alleviate the quality deterioration and extend the shelf life of crucian carp fillets,a bio-based active composite film integrating eugenol(EG)-loaded mesoporous silica nanoparticles(MSNs)modified with caffeic acid(CA)within the zein matrix(EG/CA-MSN/Zein)was developed.This study compared the effects of EG/CA-MSN/Zein,polyethylene(PE),and zein films on the quality of fish fillets during refrigerated storage.The results showed that the EG/CA-MSN/Zein film significantly retarded the increase in pH and microbial growth.Moreover,the film had higher water-holding capacity(WHC),better texture,and color stability,as indicated by low-field nuclear magnetic resonance(LF-NMR),magnetic resonance imaging(MRI),and sensory evaluation.The EG/CA-MSN/Zein composite film extended the shelf life of crucian carp fillets by 3-4 days,highlighting its potential as an environmentally friendly and efficient packaging material for aquatic products.展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.11671294)
文摘Let R_1 and R_2 be two rings with unit I. We give some characterizations of ring homomorphisms and ring isomorphisms between R_1 and R_2 in term of complete preservers of fixed points of multipliers, under some mild assumption on R_1. Applications to several kinds of operator algebras such as Banach algebras, nest algebras, matrix algebras and standard operator algebras are presented.
基金This work is supported in part by the Chinese Natural Science Foundation under Grant No. 10671026 and the Postdoctoral Fund of Heilongjiang Province
文摘Suppose R is an idempotence-diagonalizable ring. Let n and m be two arbitrary positive integers with n ≥ 3. We denote by Mn（R） the ring of all n x n matrices over R. Let （Jn（R）） be the additive subgroup of Mn（R） generated additively by all idempotent matrices. Let JJ = （Jn（R）） or Mn（R）. We describe the additive preservers of idempotence from JJ to Mm（R） when 2 is a unit of R. Thereby, we also characterize the Jordan （respectively, ring and ring anti-） homomorphisms from Mn （R） to Mm （R） when 2 is a unit of R.
文摘Let B（X） be the algebra of all bounded linear operators on an infinite-dimensional complex or real Banach space X. Given an integer n 〉 1, we show that an additive surjective map Ф on B（X） preserves Drazin invertible operators of index non-greater than n in both directions if and only if Ф is either of the form Ф（T） = aATA-1 or of the form Ф（T） = aBT＊B-1 where a is a non-zero scalar, A ： X → X and B ： X＊ → X are two bounded invertible linear or conjugate linear operators.
基金Supported by National Natural Science Foundation of China （Grant Nos. 10871111, 10501029） and the Specialized Research Fund for Doctoral Program of Higher Education （Grant No. 200800030059）
文摘Let H be a complex Hilbert space of dimension greater than 2, and B（H） denote the Banach algebra of all bounded linear operators on H. For A, B C B（H）, define the binary relation A ≤ B by A＊A = A＊B and AA＊ = AB＊. Then （B（H）, ＂〈.＂） is a partially ordered set and the relation ＂≤＂ is called the star order on B（H）. Denote by Bs（H） the set of all self-adjoint operators in B（H）. In this paper, we first characterize nonlinear continuous bijective maps on Bs（H） which preserve the star order in both directions. We characterize also additive maps （or linear maps） on B（H） （or nest algebras） which are multiplicative at some invertible operator.
文摘Chinese-German sculptor Zhou Xiaoping has been traveling between China and Germany,creating sculptures,since 2003.She has created more than 80 large,urban sculptures,each of which has become a vivid carrier of urban memories.During the past decade,she has focused on creating freeform sculptures,and she has launched a global,cross-disciplinary-artist-collaboration project,which has involved the preservation of archives for contemporary artistic creation.
基金funded by the National Natural Science Foundation of China,grant number 61605004the Fundamental Research Funds for the Central Universities,grant number FRF-TP-19-016A2Guizhou Power Grid Co.,Ltd.2024 first batch of services(2024-2026 technology R&D services for science and technology projects(in addition to national and SGCC key projects)),grant number 060100KC23100012。
文摘This study addresses the risk of privacy leakage during the transmission and sharing of multimodal data in smart grid substations by proposing a three-tier privacy-preserving architecture based on asynchronous federated learning.The framework integrates blockchain technology,the InterPlanetary File System(IPFS)for distributed storage,and a dynamic differential privacy mechanism to achieve collaborative security across the storage,service,and federated coordination layers.It accommodates both multimodal data classification and object detection tasks,enabling the identification and localization of key targets and abnormal behaviors in substation scenarios while ensuring privacy protection.This effectively mitigates the single-point failures and model leakage issues inherent in centralized architectures.A dynamically adjustable differential privacy mechanism is introduced to allocate privacy budgets according to client contribution levels and upload frequencies,achieving a personalized balance between model performance and privacy protection.Multi-dimensional experimental evaluations,including classification accuracy,F1-score,encryption latency,and aggregation latency,verify the security and efficiency of the proposed architecture.The improved CNN model achieves 72.34%accuracy and an F1-score of 0.72 in object detection and classification tasks on infrared surveillance imagery,effectively identifying typical risk events such as not wearing safety helmets and unauthorized intrusion,while maintaining an aggregation latency of only 1.58 s and a query latency of 80.79 ms.Compared with traditional static differential privacy and centralized approaches,the proposed method demonstrates significant advantages in accuracy,latency,and security,providing a new technical paradigm for efficient,secure data sharing,object detection,and privacy preservation in smart grid substations.
基金supported by the National Key Research and Development Program of China(2020AAA0109300)the Shanghai Collaborative Innovation Center of data intelligence technology(No.0232-A1-8900-24-13).
文摘Chinese abbreviations improve communicative efficiency by extracting key components from longer expressions.They are widely used in both daily communication and professional domains.However,existing abbreviation generation methods still face two major challenges.First,sequence-labeling-based approaches often neglect contextual meaning by making binary decisions at the character level,leading to abbreviations that fail to capture semantic completeness.Second,generation-basedmethods rely heavily on a single decoding process,which frequently produces correct abbreviations but ranks them lower due to inadequate semantic evaluation.To address these limitations,we propose a novel two-stage frameworkwithGeneration–Iterative Optimization forAbbreviation(GIOA).In the first stage,we design aChain-of-Thought prompting strategy and incorporate definitional and situational contexts to generate multiple abbreviation candidates.In the second stage,we introduce a Semantic Preservation Dynamic Adjustment mechanism that alternates between character-level importance estimation and semantic restoration to optimize candidate ranking.Experiments on two public benchmark datasets show that our method outperforms existing state-of-the-art approaches,achieving Hit@1 improvements of 15.15%and 13.01%,respectively,while maintaining consistent results in Hit@3.
文摘With the rapid expansion of drone applications,accurate detection of objects in aerial imagery has become crucial for intelligent transportation,urban management,and emergency rescue missions.However,existing methods face numerous challenges in practical deployment,including scale variation handling,feature degradation,and complex backgrounds.To address these issues,we propose Edge-enhanced and Detail-Capturing You Only Look Once(EHDC-YOLO),a novel framework for object detection in Unmanned Aerial Vehicle(UAV)imagery.Based on the You Only Look Once version 11 nano(YOLOv11n)baseline,EHDC-YOLO systematically introduces several architectural enhancements:(1)a Multi-Scale Edge Enhancement(MSEE)module that leverages multi-scale pooling and edge information to enhance boundary feature extraction;(2)an Enhanced Feature Pyramid Network(EFPN)that integrates P2-level features with Cross Stage Partial(CSP)structures and OmniKernel convolutions for better fine-grained representation;and(3)Dynamic Head(DyHead)with multi-dimensional attention mechanisms for enhanced cross-scale modeling and perspective adaptability.Comprehensive experiments on the Vision meets Drones for Detection(VisDrone-DET)2019 dataset demonstrate that EHDC-YOLO achieves significant improvements,increasing mean Average Precision(mAP)@0.5 from 33.2%to 46.1%(an absolute improvement of 12.9 percentage points)and mAP@0.5:0.95 from 19.5%to 28.0%(an absolute improvement of 8.5 percentage points)compared with the YOLOv11n baseline,while maintaining a reasonable parameter count(2.81 M vs the baseline’s 2.58 M).Further ablation studies confirm the effectiveness of each proposed component,while visualization results highlight EHDC-YOLO’s superior performance in detecting objects and handling occlusions in complex drone scenarios.
基金Key Science and Technology Program of Shaanxi Province,Grant/Award Number:2024SF2-GJHX-45National Natural Science Foundation of China,Grant/Award Number:82472191The Natural Science Foundation of Shaanxi Province,Grant/Award Number:2024JC-ZDXM-49。
文摘Background:Ex vivo lung perfusion(EVLP)has emerged as a critical technique for lung preservation and evaluation prior to transplantation.While conventional rat EVLP systems utilize closed-loop dual cannulation of pulmonary artery(PA)and vein,the effect of the simplified model using single PA cannulation with passive venous drainage is unknown.Methods:We developed two EVLP models in rats:a semi-closed circuit with PA-only cannulation and left atrial incision for passive venous drainage(SC-EVLP),and a closed circuit employing both arterial and venous cannulation(C-EVLP).Donor lungs were perfused for a defined duration and subsequently orthotopically transplanted.We evaluated pulmonary function parameters,histopathological injury scores,inflammatory cytokine levels,and apoptotic marker expression at the end of perfusion and posttransplantation.Results:Compared to the conventional EVLP,the SC-EVLP group exhibited significantly lower PA pressure and improved dynamic lung compliance throughout perfusion.Although the levels of tumor necrosis factor-αin the perfusate were higher in the SC-EVLP group,other cytokine levels in the perfusate and bronchoalveolar lavage fluid exhibited no significant differences.Pulmonary edema was reduced in the SC-EVLP group,as indicated by a lower lung wet-to-dry ratio.After transplantation,lungs from the SC-EVLP group exhibited lower histological injury scores,reduced apoptosis,and decreased serum cytokine levels,suggesting attenuated inflammation and tissue damage.Conclusions:In a rat model,single PA cannulation with passive venous drainage reduced pulmonary edema during EVLP and reduced lung injury and systemic inflammation after transplantation.
基金National Social Science Fund project“Research on the Narrative of the Sense of Community for the Chinese Nation in Southwest Nuo Opera”(24XMZ063).
文摘The Nuo mask is the core visual vehicle within China’s Nuo culture and constitutes a complex symbolic system through facial features(icons),patterns(indexes),and colors(symbols).Within the context of intangible cultural heritage(ICH)preservation,its value lies in the continuation and revitalization of its dynamic symbolic functions.Grounded in semiotic theory,this paper elaborates on three core dimensions of symbolic value manifested by Nuo masks in ICH preservation:a ritual symbol for living transmission,a symbol of identity for collective memory,and an aesthetic symbol as a source of creativity.
基金The authors extend their appreciation to Taif University,Saudi Arabia,for supporting this work through project No.(TU-DSPP-2024-54).
文摘Background:Locally advanced laryngeal squamous cell carcinoma(LA-LSCC)presents clinical challenges due to the lack of reliable non-invasive biomarkers.This study aimed to evaluate miR-449a as a diagnostic and prognostic biomarker in LA-LSCC.Methods:miR-449a expression was analyzed in tumor tissues,adjacent normal tissues,and serum from 81 LA-LSCC patients and 50 controls using quantitative real-time reverse transcription polymerase chain reaction(qRT-PCR).We assessed the diagnostic accuracy by Receiver Operating Characteristic curve(ROC curves),clinicopathological associations,survival outcomes(Kaplan-Meier),and treatment response dynamics.Results:miR-449a was significantly downregulated in LA-LSCC tissues(p<0.0001)and serum(p<0.0001),with a strong tissue-serum correlation(R^(2)=0.988).Tissue miR-449a demonstrated a diagnostic accuracy(Area Under the Curve,AUC=0.857),while serum showed moderate accuracy(AUC=0.734).High miR-449a expression correlated with favorable clinicopathological features and improved survival(median overall survival:67.82 vs.23.74 months;p=0.0012).Multivariate analysis confirmed miR-449a as an independent prognostic factor(p<0.001).miR-449a levels increased post-treatment,particularly in responders to chemotherapy/radiation(p<0.0001).Conclusion:miR-449a serves as a non-invasive biomarker for LA-LSCC diagnosis,prognosis,and treatment monitoring.Its dynamic expression highlights potential for risk stratification and therapy response prediction,warranting further validation in larger cohorts.
文摘Instrument separation is a critical complication during root canal therapy,impacting treatment success and long-term tooth preservation.The etiology of instrument separation is multifactorial,involving the intricate anatomy of the root canal system,instrument-related factors,and instrumentation techniques.Instrument separation can hinder thorough cleaning,shaping,and obturation of the root canal,posing challenges to successful treatment outcomes.Although retrieval of separated instrument is often feasible,it carries risks including perforation,excessive removal of tooth structure and root fractures.Effective management of separated instruments requires a comprehensive understanding of the contributing factors,meticulous preoperative assessment,and precise evaluation of the retrieval difficulty.The application of appropriate retrieval techniques is essential to minimize complications and optimize clinical outcomes.The current manuscript provides a framework for understanding the causes,risk factors,and clinical management principles of instrument separation.By integrating effective strategies,endodontists can enhance decision-making,improve endodontic treatment success and ensure the preservation of natural dentition.
基金Supported by the National Natural Science Foundation of China(U22B6004)Project of PetroChina Research Institute of Petroleum Exploration and Development(2022yjcq03)Core Technology Key Project of China Petroleum Changqing Oilfield Company(KJZX2023-01).
文摘In addition to the organic matter type,abundance,thermal maturity,and shale reservoir space,the preservation conditions of source rocks play a key factor in affecting the quantity and quality of retained hydrocarbons in source rocks of lacustrine shale,yet this aspect has received little attention.This paper,based on the case analysis,explores how preservation conditions influence the enrichment of mobile hydrocarbons in shale oil.Research showns that good preservation conditions play three key roles.(1)Ensure the retention of sufficient light hydrocarbons(C_(1)–C_(13)),medium hydrocarbons(C_(14)–C_(25))and small molecular aromatics(including 1–2 benzene rings)in the formation,which enhances the fluidity and flow of shale oil;(2)Maintain a high energy field(abnormally high pressure),thus facilitating the maximum outflow of shale oil;(3)Ensure that the retained hydrocarbons have the miscible flow condition of multi-component hydrocarbons(light hydrocarbons,medium hydrocarbons,heavy hydrocarbons,and heteroatomic compounds),so that the heavy hydrocarbons(C_(25+))and heavy components(non-hydrocarbons and asphaltenes)have improved fluidity and maximum flow capacity.In conclusion,in addition to the advantages of organic matter type,abundance,thermal maturity,and reservoir space,good preservation conditions of shale layers are essential for the formation of economically viable shale oil reservoirs,which should be incorporated into the evaluation criteria of shale oil-rich areas/segments and considered a necessary factor when selecting favorable exploration targets.
基金supported by the National Key R&D Program of China(No.2022YFC2803900)the National Natural Science Foundation of China(No.42276191)Zhejiang University Students Science and Technology Innovation Activity Plan(New Talent Plan)(No.2024R401185).
文摘The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model.To address the limitations of traditional methods in obtaining high-quality sediment,a novel sampling system with 6000 m operational capability and three-month endurance was developed.It is equipped with three sediment samplers,a set of formaldehyde preservation solution injection devices.The system is controlled by a low-power,timing-triggered controllers.To investigate low-disturbance rheological mechanisms,gap controlled rheological tests were conducted to optimize the structural design of the sampling and sealing assembly.Stress-controlled shear rheological tests were employed to investigate the mechanisms governing yield stress in sediments under varying temperature conditions and boundary roughness.Additionally,the coupled Eulerian-Lagrangian(CEL)method and sediment rheological constitutive models were employed to simulate tube-soil interaction dynamics and sediment disturbance.The radial heterogeneity of sediment disturbance and friction variation of the sampling tube were revealed.The tube was completely“plugged”at a penetration depth of 261 mm,providing critical data support to the penetration depth parameters.The deep-sea pressure test and South China Sea field trials demonstrated the system’s capability to collect and preserve quantitative time-series sediment samples with high fidelity.
基金supported by the National Natural Science Foundation of China(Nos.42488101,42141021,42172149,42172168,U2244209)the Tencent Foundation through the XPLORER PRIZE。
文摘Occurrence and abundance of molecular hydrogen in natural geologic reservoirs are enigmatic,due to its various sources,diverse migration pathways and complicated biological and chemical reactions.Natural gas samples containing hydrogen from producing wells in several sedimentary basins in China were collected in this study,and gas abundances and isotopic compositions of these gases were compared with those in global petroliferous basins and deep intrusive rocks.Several geochemical indicators were suggested for identifying sources,migration and accumulation mechanisms of hydrogen in the subsurface environment.Hydrogen contents in natural gas deposits have contributions from various sources with the following high-to-low order:microbial degradation>serpentinization>deep mantle volatile release>radiation-induced water decomposition>thermal cracking of organic matter.A hydrogen-rich reservoir in Kansas,USA,is specifically analyzed to determine its formation mechanism.This study suggests that future exploration of geological hydrogen resources may focus on the igneous rock bodies with overlying dense sedimentary rocks in the continental rift systems.
基金supported by the National Natural Science Foundation of China(Nos.52308300,52370025,52108266).
文摘The heritage preservation is of great intractability to the conservators as each kind of heritage material has unique and diverse requirements on temperature,humidity and air cleanliness.It is promising for metal-organic frameworks(MOFs),the multifunctional environment remediation materials,to be applied in heritage environmental protection.The advantages of MOFs lie in their multifunction like adsorption,photocatalysis,sterilization,as well as the controllable structure and properties that could be flexibly adjusted as demands,helping the heritage against various environmental threats.Thereby,the applications and the corresponding mechanisms of MOFs in cultural heritage preservation were reviewed in this work,including harmful gas adsorption,surface waterproofing,particulate matters(PM)removal,anti-bacterial and humidity control of environment.Finally,the selection principles and precautions of MOFs in heritage preservation were discussed,aiming to provide a forward-looking direction for the selection and application of MOFs.
基金Supported by the Joint Fund for Enterprise Innovation and Development of the National Natural Science Foundation of China(U23B20154)General Program of the National Natural Science Foundation of China(42372169)。
文摘To address the challenges in studying the pore formation and evolution processes,and unclear preservation mechanisms of deep to ultra-deep carbonate rocks,a high-temperature and high-pressure visualization simulation experimental device was developed for ultra-deep carbonate reservoirs.Carbonate rock samples from the Sichuan Basin and Tarim Basin were used to simulate the dissolution-precipitation process of deep to ultra-deep carbonate reservoirs in an analogous geological setting.This unit comprises four core modules:an ultra-high temperature,high pressure triaxial stress core holder module(temperature higher than 300°C,pressure higher than 150 MPa),a multi-stage continuous flow module with temperature-pressure regulation,an ultra-high temperature-pressure sapphire window cell and an in-situ high-temperature-pressure fluid property measurement module and real-time ultra-high temperature-pressure permeability detection module.The new experimental device was used for simulation experiment,the geological insights were obtained in three aspects.First,the pore-throat structure of carbonate is controlled by lithology and initial pore-throat structure,and fluid type,concentration and dissolution duration determine the degree of dissolution.The dissolution process exhibits two evolution patterns.The dissolution scale is positively correlated to the temperature and pressure,and the pore-forming peak period aligns well with the hydrocarbon generation peak period.Second,the dissolution potential of dolomite in an open flow system is greater than that of limestone,and secondary dissolved pores formed continuously are controlled by the type and concentration of acidic fluids and the initial physical properties.These pores predominantly distribute along pre-existing pore/fracture zones.Third,in a nearly closed diagenetic system,after the chemical reaction between acidic fluids and carbonate rock reaches saturation and dynamic equilibrium,the pore structure no longer changes,keeping pre-existing pores well-preserved.These findings have important guiding significance for the evaluation of pore-throat structure and development potential of deep to ultra-deep carbonate reservoirs,and the prediction of main controlling factors and distribution of high-quality carbonate reservoirs.
文摘The umbrella term"neurodege ne rative disorders"(NDDs) refers to several conditions characterized by a progressive loss of structure and function of cells belonging to the nervous system.Such diseases affect more than 50million people worldwide.Neurodegenerative disorders are characterized by sundry factors and pathophysiological mechanisms that a re challenging to be fully profiled.Many of these rely on cell signaling pathways to preserve homeostasis,involving second messengers such as cyclic adenosine monophosphate (cAMP)and cyclic guanosine 3',5'-monophosphate(cGMP).Their ability to control the duration and amplitude of the signaling cascade is given by the presence of several common and uncommon effectors.Protein kinases A and G (PKA and PKG),phosphodiesterases (PDEs),and scaffold proteins are among them.
文摘In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.
文摘To alleviate the quality deterioration and extend the shelf life of crucian carp fillets,a bio-based active composite film integrating eugenol(EG)-loaded mesoporous silica nanoparticles(MSNs)modified with caffeic acid(CA)within the zein matrix(EG/CA-MSN/Zein)was developed.This study compared the effects of EG/CA-MSN/Zein,polyethylene(PE),and zein films on the quality of fish fillets during refrigerated storage.The results showed that the EG/CA-MSN/Zein film significantly retarded the increase in pH and microbial growth.Moreover,the film had higher water-holding capacity(WHC),better texture,and color stability,as indicated by low-field nuclear magnetic resonance(LF-NMR),magnetic resonance imaging(MRI),and sensory evaluation.The EG/CA-MSN/Zein composite film extended the shelf life of crucian carp fillets by 3-4 days,highlighting its potential as an environmentally friendly and efficient packaging material for aquatic products.
