In this paper,we propose a random access scheme termed sign-compute diversity slotted ALOHA(SCDSA).The SCDSA scheme combines diversity transmission with compute-and-forward.Without considering the capture effect and m...In this paper,we propose a random access scheme termed sign-compute diversity slotted ALOHA(SCDSA).The SCDSA scheme combines diversity transmission with compute-and-forward.Without considering the capture effect and multiple user detection techniques,our scheme can reach a high throughput of 0.98 without feedback under finite frame size settings,where the upper bound on performance is 1.Moreover,a lower bound on throughput performance is derived,which is tight in some parameter settings and can be used to approximate theoretical performance.Simulation results validate our analysis and confirm the advantages of our proposed scheme.展开更多
Triterpenoids are valuable medicinal scaffolds,characterized by excellent pharmacological properties and the presence of hydroxyl and carboxyl groups that allow for further structural modifications.Expanding the scope...Triterpenoids are valuable medicinal scaffolds,characterized by excellent pharmacological properties and the presence of hydroxyl and carboxyl groups that allow for further structural modifications.Expanding the scope of oxidative modifications on these molecules is crucial for increasing their synthetic structural diversity and unlocking new potential pharmacological activities.However,the progress has been limited by the scarcity of suitable tailoring enzymes.Here,we reported a break-through in achieving targeted and remote dual-site oxidation of licorice triterpenoids using a single P450 mutant.This approach successfully enabled the selective synthesis of the rare triterpenoid,liquiritic acid and 24-OH-liquiritic acid.Our findings demonstrate that microenvironmental accessibility engineering of triterpenoid substrates within the P450 enzyme is essential for continuous and regioselective oxidation.This study not only sheds light on the mechanistic aspects of P450 catalysis but also expands the enzymatic toolkit for selective oxidative modifications in triterpenoid biosynthesis.展开更多
The performance of data restore is one of the key indicators of user experience for backup storage systems.Compared to the traditional offline restore process,online restore reduces downtime during backup restoration,...The performance of data restore is one of the key indicators of user experience for backup storage systems.Compared to the traditional offline restore process,online restore reduces downtime during backup restoration,allowing users to operate on already restored files while other files are still being restored.This approach improves availability during restoration tasks but suffers from a critical limitation:inconsistencies between the access sequence and the restore sequence.In many cases,the file a user needs to access at a given moment may not yet be restored,resulting in significant delays and poor user experience.To this end,we present Histore,which builds on the user’s historical access sequence to schedule the restore sequence,in order to reduce users’access delayed time.Histore includes three restore approaches:(i)the frequency-based approach,which restores files based on historical file access frequencies and prioritizes ensuring the availability of frequently accessed files;(ii)the graph-based approach,which preferentially restores the frequently accessed files as well as their correlated files based on historical access patterns,and(iii)the trie-based approach,which restores particular files based on both users’real-time and historical access patterns to deduce and restore the files to be accessed in the near future.We implement a prototype of Histore and evaluate its performance from multiple perspectives.Trace-driven experiments on two datasets show that Histore significantly reduces users’delay time by 4-700×with only 1.0%-14.5%additional performance overhead.展开更多
After securing a market for their dried red chilli peppers in China,elated farmers in Uganda are expanding the spicy crop cultivation to thousands of acres.China’s increasing appetite for international cuisine and sp...After securing a market for their dried red chilli peppers in China,elated farmers in Uganda are expanding the spicy crop cultivation to thousands of acres.China’s increasing appetite for international cuisine and spices has created a most welcome demand for high-quality chillies.And given Uganda’s unique climate and soil conditions that allow for diverse chilli varieties,the East African country has a competitive edge.This has led to Uganda and China now having trade agreements in place,facilitating exports.展开更多
As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and ...As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities.展开更多
The accessibility of urban public transit directly influences residents’quality of life,travel behavior,and social equity.Its correlation with housing prices has garnered significant attention across disciplines such...The accessibility of urban public transit directly influences residents’quality of life,travel behavior,and social equity.Its correlation with housing prices has garnered significant attention across disciplines such as geography,economics,and urban planning.Although much existing research focuses on the impact of individual transportation facilities on housing prices,there is a notable gap in comprehensive analyses that assess the influence of overall urban transit accessibility on housing market dynamics.This study selected the main urban area of Hefei,China,as a case to investigate the spatial distribution of housing prices and evaluate public transit accessibility in 2022.Employing techniques such as the optimized parameter geographical detector and local spatial regression models,the study aimed to elucidate the effects and underlying mechanisms of urban transit accessibility on housing prices.The findings revealed that:1)housing prices in Hefei exhibited a clustered spatial pattern,with high prices concentrated in the city center and lower prices in peripheral areas,forming three distinct high-price hotspots with a‘belt-like’distribution;2)public transit accessibility showed a‘coreperiphery’structure,with accessibility declining in a‘circumferential’pattern around the city center.Based on the‘housing price-accessibility’dimension,four categories were identified:high price-high accessibility(37.25%),high price-low accessibility(19.07%),low price-high accessibility(21.95%),and low price-low accessibility(21.73%);3)the impact of transit accessibility on housing prices was spatially heterogeneous,with bus travel showing the strongest explanatory power(0.692),followed by automobile,subway,and bicycle travel.The interaction of these transportation modes generated a synergistic effect on housing price differentiation,with most influencing factors contributing more than 25%.These findings offer valuable insights for optimizing the spatial distribution of public transit infrastructure and improving both urban housing quality and residents’living standards.展开更多
Central nervous system(CNS) axons fail to regenerate following brain or spinal cord injury(SCI),which typically leads to permanent neurological deficits.Peripheral nervous system axons,howeve r,can regenerate followin...Central nervous system(CNS) axons fail to regenerate following brain or spinal cord injury(SCI),which typically leads to permanent neurological deficits.Peripheral nervous system axons,howeve r,can regenerate following injury.Understanding the mechanisms that underlie this difference is key to developing treatments for CNS neurological diseases and injuries characterized by axonal damage.To initiate repair after peripheral nerve injury,dorsal root ganglion(DRG) neurons mobilize a pro-regenerative gene expression program,which facilitates axon outgrowth.展开更多
Under the background of‘the Belt and Road’and‘China-Mongolia-Russia Economic Corridor’initiatives,this paper studied the urban accessibility level,regional accessibility pattern and regional spatial effects along ...Under the background of‘the Belt and Road’and‘China-Mongolia-Russia Economic Corridor’initiatives,this paper studied the urban accessibility level,regional accessibility pattern and regional spatial effects along the Primorsky No.1 and No.2 transportation corridors.First,the evaluation of urban accessibility level with and without Primorsky No.1 and No.2 high-speed rails(HSRs)opening was conducted with two indicators,i.e.,the weighted average travel time,and the economic potential.After the evaluation,the spatial differentiation pattern of the accessibility changes with and without Primorsky No.1 and No.2 HSRs opening was performed respectively using ArcGIS.On these bases,the regional spatial effects brought by Primorsky No.1 and No.2 HSRs opening were studied.The results are as following.First,the urban accessibility level will be greatly improved by the opening of Primorsky No.1 and No.2 HSRs.All adjacent cities will be integrated into‘1 h HSR communication circle’and the whole journey will be integrated into‘4 h HSR communication circle’along Primorsky No.1 and No.2 corridors,respectively.The HSR accessibility of Primorsky No.1 corridor is stronger than that of Primorsky No.2 corridor.But the HSR accessibility improvement degree of Primorsky No.1 corridor is weaker than that of Primorsky No.2 corridor.Second,spatially,along Primorsky No.1 and No.2 corridors,the HSR accessibility level of the cities which are located in China is stronger than those cities located in Russia,showing the‘High West,Low East’patterns.The HSR accessibility improvement degree of the cities which are located in Russia and Sino-Russian border is stronger than those cities located in China,showing the‘High East,Low West’patterns.Third,Primorsky No.1 and No.2 corridors could connect the China’s‘Heilongjiang Land Sea Silk Road Economic Belt’and‘Changchun-Jilin-Tumen Development Pilot Zone’respectively,gradually involving into the development of China’s Harbin-Changchun Megalopolis.Relying on Harbin(China)and Changchun(China),Primorsky No.1 and No.2 HSRs could connect Northeast China-Beijing HSR,accelerating the diffusion of population,economy and other flows from China’s Beijing-Tianjin-Hebei Urban Agglomeration to Northeast China,and then to Russia’s Far East Federal District.Relying on Suifenhe(China)and Hunchun(China),Primorsky No.1 and No.2 HSRs could be conducive to the development of the second largest sea channels for Northeast China,creating the Northeast Asian Urban Belt,and new sea-rail intermodal pattern among China,Russia,Democratic People’s Republic of Korea,Japan and Republic of Korea.Relying on Vladivostok(Russia)and Zarubino(Russia),Primorsky No.1 and No.2 corridors could connect the‘Ice Silk Road’,building the‘Sino-Russian Northern Maritime Corridor’and‘Sino-Russian Arctic Blue Economic Areas’.展开更多
The 6G smart Fog Radio Access Network(F-RAN)is an integration of 6G network intelligence technologies and the F-RAN architecture.Its aim is to provide low-latency and high-performance services for massive access devic...The 6G smart Fog Radio Access Network(F-RAN)is an integration of 6G network intelligence technologies and the F-RAN architecture.Its aim is to provide low-latency and high-performance services for massive access devices.However,the performance of current 6G network intelligence technologies and its level of integration with the architecture,along with the system-level requirements for the number of access devices and limitations on energy consumption,have impeded further improvements in the 6G smart F-RAN.To better analyze the root causes of the network problems and promote the practical development of the network,this study used structured methods such as segmentation to conduct a review of the topic.The research results reveal that there are still many problems in the current 6G smart F-RAN.Future research directions and difficulties are also discussed.展开更多
Attribute-based Encryption(ABE)enhances the confidentiality of Electronic Health Records(EHR)(also known as Personal Health Records(PHR))by binding access rights not to individual identities,but to user attribute sets...Attribute-based Encryption(ABE)enhances the confidentiality of Electronic Health Records(EHR)(also known as Personal Health Records(PHR))by binding access rights not to individual identities,but to user attribute sets such as roles,specialties,or certifications.This data-centric cryptographic paradigm enables highly fine-grained,policydriven access control,minimizing the need for identity management and supporting scalable multi-user scenarios.This paper presents a comprehensive and critical survey of ABE schemes developed specifically for EHR/PHR systems over the past decade.It explores the evolution of these schemes,analyzing their design principles,strengths,limitations,and the level of granularity they offer in access control.The review also evaluates the security guarantees,efficiency,and practical applicability of these schemes in real-world healthcare environments.Furthermore,the paper outlines the current state of ABE as a mechanism for safeguarding EHR data and managing user access,while also identifying the key challenges that remain.Open issues such as scalability,revocation mechanisms,policy updates,and interoperability are discussed in detail,providing valuable insights for researchers and practitioners aiming to advance the secure management of health information systems.展开更多
High reliability applications in dense access scenarios have become one of the main goals of 6G environments.To solve the access collision of dense Machine Type Communication(MTC)devices in cell-free communication sys...High reliability applications in dense access scenarios have become one of the main goals of 6G environments.To solve the access collision of dense Machine Type Communication(MTC)devices in cell-free communication systems,an intelligent cooperative secure access scheme based on multi-agent reinforcement learning and federated learning is proposed,that is,the Preamble Slice Orderly Queue Access(PSOQA)scheme.In this scheme,the preamble arrangement is combined with the access control.The preamble arrangement is realized by preamble slices which is from the virtual preamble pool.The access devices learn to queue orderly by deep reinforcement learning.The orderly queue weakens the random and avoids collision.A preamble slice is assigned to an orderly access queue at each access time.The orderly queue is determined by interaction information among multiple agents.With the federated reinforcement learning framework,the PSOQA scheme is implemented to guarantee the privacy and security of agents.Finally,the access performance of PSOQA is compared with other random contention schemes in different load scenarios.Simulation results show that PSOQA can not only improve the access success rate but also guarantee low-latency tolerant performances.展开更多
The secured access is studied in this paper for the network of the image remote sensing.Each sensor in this network encounters the information security when uploading information of the images wirelessly from the sens...The secured access is studied in this paper for the network of the image remote sensing.Each sensor in this network encounters the information security when uploading information of the images wirelessly from the sensor to the central collection point.In order to enhance the sensing quality for the remote uploading,the passive reflection surface technique is employed.If one eavesdropper that exists nearby this sensor is keeping on accessing the same networks,he may receive the same image from this sensor.Our goal in this paper is to improve the SNR of legitimate collection unit while cut down the SNR of the eavesdropper as much as possible by adaptively adjust the uploading power from this sensor to enhance the security of the remote sensing images.In order to achieve this goal,the secured energy efficiency performance is theoretically analyzed with respect to the number of the passive reflection elements by calculating the instantaneous performance over the channel fading coefficients.Based on this theoretical result,the secured access is formulated as a mathematical optimization problem by adjusting the sensor uploading power as the unknown variables with the objective of the energy efficiency maximization while satisfying any required maximum data rate of the eavesdropper sensor.Finally,the analytical expression is theoretically derived for the optimum uploading power.Numerical simulations verify the design approach.展开更多
BACKGROUND Central venous access is essential for administering chemotherapy in patients with gastrointestinal cancer.Peripherally inserted central catheters(PICC)and totally implantable venous access ports(TIVAP)are ...BACKGROUND Central venous access is essential for administering chemotherapy in patients with gastrointestinal cancer.Peripherally inserted central catheters(PICC)and totally implantable venous access ports(TIVAP)are widely used,but comparative data regarding their impact on catheter-related complications and quality of life(QoL)remain limited.AIM To evaluate the impact of TIVAPs compared with PICC on catheter-related complications and QoL in patients with gastrointestinal cancer undergoing chemotherapy.METHODS This retrospective study included adults with gastrointestinal cancer who underwent central venous access device insertion for chemotherapy at our institution between December 2021 and December 2024.Inclusion criteria encompassed indications for intermittent intravenous chemotherapy,anticipated treatment duration of≥12 weeks,an adequate preoperative hematologic profile,accessible upper body veins,and complete medical records.Patients were excluded if they had an anticipated survival of less than three months,active systemic infection,severe thrombosis or coagulopathy,communication barriers,or an urgent need for dialysis access.Patients were assigned to either the PICC or TIVAP group based on device type.Data collected included demographic variables,cancer characteristics,insertion procedure details,complications,and QoL,assessed via the EuroQol 5-Dimensions-3 levels,visual analogue scale,and the European Organization for Research and Treatment of Cancer QoL Questionnaire-Core 30.RESULTS A total of 346 patients were analyzed.Baseline demographic,clinical,and cancer characteristics were similar between groups.The TIVAP group demonstrated a significantly lower incidence of catheter-related complications than the PICC group,with no pneumothorax occurring in either group.QoL assessments at baseline were comparable.At one month,the TIVAP group exhibited significantly higher EuroQoL Five Dimensions health state scores and QLQ-C30 global health status scores.Multivariate analysis identified TIVAP use,catheter tip placement in the distal superior vena cava/right atrium,prophylactic antibiotic administration,and antimicrobial dressing application as independent protective factors associated with reduced complications and improved QoL.CONCLUSION In patients with gastrointestinal cancer undergoing chemotherapy,TIVAPs are associated with a lower incidence of catheter-related complications and improved QoL than PICCs.Optimal device selection,precise catheter tip positioning,and effective perioperative management are critical for minimizing complications and enhancing patient-reported outcomes during treatment.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is notorious for its aggressive progression and dismal prognosis,with chromatin accessibility dynamics emerging as pivotal yet poorly understood drivers.AIM To dissect how multi...BACKGROUND Hepatocellular carcinoma(HCC)is notorious for its aggressive progression and dismal prognosis,with chromatin accessibility dynamics emerging as pivotal yet poorly understood drivers.AIM To dissect how multilayered chromatin regulation sustains oncogenic transcription and tumor-stroma crosstalk in HCC,we combined multiomics single cell analysis.METHODS We integrated single-cell RNA sequencing and paired single-cell assay for transposase-accessible chromatin with sequencing data of HCC samples,complemented by bulk RNA sequencing validation across The Cancer Genome Atlas,Liver Cancer Institute,and GSE25907 cohorts.Cell type-specific chromatin architectures were resolved via ArchR,with regulatory hubs identified through peak-to-gene linkages and coaccessibility networks.Functional validation employed A485-mediated histone 3 lysine 27 acetylation suppression and small interfering RNA targeting DGAT1.RESULTS Malignant hepatocytes exhibited expanded chromatin accessibility profiles,characterized by increased numbers of accessible peaks and larger physical regions despite reduced peak intensity.Enhancer-like peaks enriched in malignant regulation,forming long-range hubs.Eighteen enhancer-like peak-related genes showed tumor-specific overexpression and diagnostic accuracy,correlating with poor prognosis.Intercellular coaccessibility analysis revealed tumor-stroma symbiosis via shared chromatin states.Pharmacological histone 3 lysine 27 acetylation inhibition paradoxically downregulated DGAT1,the hub gene most strongly regulated by chromatin accessibility.DGAT1 knockdown suppressed cell proliferation.CONCLUSION Multilayered chromatin reprogramming sustains HCC progression through tumor-stroma crosstalk and DGAT1-related oncogenic transcription,defining targetable epigenetic vulnerabilities.展开更多
The envisioned 6G wireless networks demand advanced Multiple Access (MA) schemes capable of supporting ultra-low latency, massive connectivity, high spectral efficiency, and energy efficiency (EE), especially as the c...The envisioned 6G wireless networks demand advanced Multiple Access (MA) schemes capable of supporting ultra-low latency, massive connectivity, high spectral efficiency, and energy efficiency (EE), especially as the current 5G networks have not achieved the promised 5G goals, including the projected 2000 times EE improvement over the legacy 4G Long Term Evolution (LTE) networks. This paper provides a comprehensive survey of Artificial Intelligence (AI)-enabled MA techniques, emphasizing their roles in Spectrum Sensing (SS), Dynamic Resource Allocation (DRA), user scheduling, interference mitigation, and protocol adaptation. In particular, we systematically analyze the progression of traditional and modern MA schemes, from Orthogonal Multiple Access (OMA)-based approaches like Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) to advanced Non-Orthogonal Multiple Access (NOMA) methods, including power domain-NOMA, Sparse Code Multiple Access (SCMA), and Rate Splitting Multiple Access (RSMA). The study further categorizes AI techniques—such as Machine Learning (ML), Deep Learning (DL), Reinforcement Learning (RL), Federated Learning (FL), and Explainable AI (XAI)—and maps them to practical challenges in Dynamic Spectrum Management (DSM), protocol optimization, and real-time distributed decision-making. Optimization strategies, including metaheuristics and multi-agent learning frameworks, are reviewed to illustrate the potential of AI in enhancing energy efficiency, system responsiveness, and cross-layer RA. Additionally, the review addresses security, privacy, and trust concerns, highlighting solutions like privacy-preserving ML, FL, and XAI in 6G and beyond. By identifying research gaps, challenges, and future directions, this work offers a structured resource for researchers and practitioners aiming to integrate AI into 6G MA systems for intelligent, scalable, and secure wireless communications.展开更多
To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put...To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put forward to calculate the uncertainty of the system' s determinations on the irregular access behaviors.Secondly,based on the security entropy,security theorems of hybrid cloud are defined.Finally,typical access control models are analyzed by the method,the method's practicability is validated,and security and applicability of these models are compared.Simulation results prove that the proposed method is suitable for the security quantitative analysis of the access control model and evaluation to access control capability in hybrid cloud.展开更多
文摘In this paper,we propose a random access scheme termed sign-compute diversity slotted ALOHA(SCDSA).The SCDSA scheme combines diversity transmission with compute-and-forward.Without considering the capture effect and multiple user detection techniques,our scheme can reach a high throughput of 0.98 without feedback under finite frame size settings,where the upper bound on performance is 1.Moreover,a lower bound on throughput performance is derived,which is tight in some parameter settings and can be used to approximate theoretical performance.Simulation results validate our analysis and confirm the advantages of our proposed scheme.
基金supported by grants from the National Natural Science Foundation of China(Nos.22108154,22138006,32171430).
文摘Triterpenoids are valuable medicinal scaffolds,characterized by excellent pharmacological properties and the presence of hydroxyl and carboxyl groups that allow for further structural modifications.Expanding the scope of oxidative modifications on these molecules is crucial for increasing their synthetic structural diversity and unlocking new potential pharmacological activities.However,the progress has been limited by the scarcity of suitable tailoring enzymes.Here,we reported a break-through in achieving targeted and remote dual-site oxidation of licorice triterpenoids using a single P450 mutant.This approach successfully enabled the selective synthesis of the rare triterpenoid,liquiritic acid and 24-OH-liquiritic acid.Our findings demonstrate that microenvironmental accessibility engineering of triterpenoid substrates within the P450 enzyme is essential for continuous and regioselective oxidation.This study not only sheds light on the mechanistic aspects of P450 catalysis but also expands the enzymatic toolkit for selective oxidative modifications in triterpenoid biosynthesis.
基金supported in part by National Key R&D Program of China(2022YFB4501200),National Natural Science Foundation of China(62332018)Science and Technology Program(2024NSFTD0031,2024YFHZ0339 and 2025ZNSFSC0497).
文摘The performance of data restore is one of the key indicators of user experience for backup storage systems.Compared to the traditional offline restore process,online restore reduces downtime during backup restoration,allowing users to operate on already restored files while other files are still being restored.This approach improves availability during restoration tasks but suffers from a critical limitation:inconsistencies between the access sequence and the restore sequence.In many cases,the file a user needs to access at a given moment may not yet be restored,resulting in significant delays and poor user experience.To this end,we present Histore,which builds on the user’s historical access sequence to schedule the restore sequence,in order to reduce users’access delayed time.Histore includes three restore approaches:(i)the frequency-based approach,which restores files based on historical file access frequencies and prioritizes ensuring the availability of frequently accessed files;(ii)the graph-based approach,which preferentially restores the frequently accessed files as well as their correlated files based on historical access patterns,and(iii)the trie-based approach,which restores particular files based on both users’real-time and historical access patterns to deduce and restore the files to be accessed in the near future.We implement a prototype of Histore and evaluate its performance from multiple perspectives.Trace-driven experiments on two datasets show that Histore significantly reduces users’delay time by 4-700×with only 1.0%-14.5%additional performance overhead.
文摘After securing a market for their dried red chilli peppers in China,elated farmers in Uganda are expanding the spicy crop cultivation to thousands of acres.China’s increasing appetite for international cuisine and spices has created a most welcome demand for high-quality chillies.And given Uganda’s unique climate and soil conditions that allow for diverse chilli varieties,the East African country has a competitive edge.This has led to Uganda and China now having trade agreements in place,facilitating exports.
基金supported by the National Science Foundation of China(No.62171387)the Science and Technology Program of Sichuan Province(No.2024NSFSC0468)the China Postdoctoral Science Foundation(No.2019M663475).
文摘As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities.
基金Under the auspices of the National Natural Science Foundation of China(No.42271224,41901193)Ministry of Edu cation Humanities and Social Sciences Research Planning Fund Project of China(No.24YJAZH190)+1 种基金Anhui Province Excellent Youth Research Project in Universities(No.2022AH030019)Anhui Social Sciences Innovation Development Research Project(No.2024CXQ503)。
文摘The accessibility of urban public transit directly influences residents’quality of life,travel behavior,and social equity.Its correlation with housing prices has garnered significant attention across disciplines such as geography,economics,and urban planning.Although much existing research focuses on the impact of individual transportation facilities on housing prices,there is a notable gap in comprehensive analyses that assess the influence of overall urban transit accessibility on housing market dynamics.This study selected the main urban area of Hefei,China,as a case to investigate the spatial distribution of housing prices and evaluate public transit accessibility in 2022.Employing techniques such as the optimized parameter geographical detector and local spatial regression models,the study aimed to elucidate the effects and underlying mechanisms of urban transit accessibility on housing prices.The findings revealed that:1)housing prices in Hefei exhibited a clustered spatial pattern,with high prices concentrated in the city center and lower prices in peripheral areas,forming three distinct high-price hotspots with a‘belt-like’distribution;2)public transit accessibility showed a‘coreperiphery’structure,with accessibility declining in a‘circumferential’pattern around the city center.Based on the‘housing price-accessibility’dimension,four categories were identified:high price-high accessibility(37.25%),high price-low accessibility(19.07%),low price-high accessibility(21.95%),and low price-low accessibility(21.73%);3)the impact of transit accessibility on housing prices was spatially heterogeneous,with bus travel showing the strongest explanatory power(0.692),followed by automobile,subway,and bicycle travel.The interaction of these transportation modes generated a synergistic effect on housing price differentiation,with most influencing factors contributing more than 25%.These findings offer valuable insights for optimizing the spatial distribution of public transit infrastructure and improving both urban housing quality and residents’living standards.
基金supported by the Canada Foundation for Innovation (Project#44220)the Natural Sciences and Engineering Research Council of Canada (RGPIN-2024-03986)+3 种基金the Michael Smith Foundation for Health Research BCthe financial support of Health Canada,through the Canada Brain Research Fund,an innovative partnership between the Government of Canada (through Health Canada),Brain Canada Foundationthe Azrieli Foundationsupported by a Canadian Institutes of Health Research (CIHR) Canada Graduate Scholarship–Master’s Award。
文摘Central nervous system(CNS) axons fail to regenerate following brain or spinal cord injury(SCI),which typically leads to permanent neurological deficits.Peripheral nervous system axons,howeve r,can regenerate following injury.Understanding the mechanisms that underlie this difference is key to developing treatments for CNS neurological diseases and injuries characterized by axonal damage.To initiate repair after peripheral nerve injury,dorsal root ganglion(DRG) neurons mobilize a pro-regenerative gene expression program,which facilitates axon outgrowth.
基金Under the auspices of Heilongjiang Provincial Natural Science Foundation of China(No.YQ2024D012),National Natural Science Foundation of China(No.42071162,42101165,42501220)。
文摘Under the background of‘the Belt and Road’and‘China-Mongolia-Russia Economic Corridor’initiatives,this paper studied the urban accessibility level,regional accessibility pattern and regional spatial effects along the Primorsky No.1 and No.2 transportation corridors.First,the evaluation of urban accessibility level with and without Primorsky No.1 and No.2 high-speed rails(HSRs)opening was conducted with two indicators,i.e.,the weighted average travel time,and the economic potential.After the evaluation,the spatial differentiation pattern of the accessibility changes with and without Primorsky No.1 and No.2 HSRs opening was performed respectively using ArcGIS.On these bases,the regional spatial effects brought by Primorsky No.1 and No.2 HSRs opening were studied.The results are as following.First,the urban accessibility level will be greatly improved by the opening of Primorsky No.1 and No.2 HSRs.All adjacent cities will be integrated into‘1 h HSR communication circle’and the whole journey will be integrated into‘4 h HSR communication circle’along Primorsky No.1 and No.2 corridors,respectively.The HSR accessibility of Primorsky No.1 corridor is stronger than that of Primorsky No.2 corridor.But the HSR accessibility improvement degree of Primorsky No.1 corridor is weaker than that of Primorsky No.2 corridor.Second,spatially,along Primorsky No.1 and No.2 corridors,the HSR accessibility level of the cities which are located in China is stronger than those cities located in Russia,showing the‘High West,Low East’patterns.The HSR accessibility improvement degree of the cities which are located in Russia and Sino-Russian border is stronger than those cities located in China,showing the‘High East,Low West’patterns.Third,Primorsky No.1 and No.2 corridors could connect the China’s‘Heilongjiang Land Sea Silk Road Economic Belt’and‘Changchun-Jilin-Tumen Development Pilot Zone’respectively,gradually involving into the development of China’s Harbin-Changchun Megalopolis.Relying on Harbin(China)and Changchun(China),Primorsky No.1 and No.2 HSRs could connect Northeast China-Beijing HSR,accelerating the diffusion of population,economy and other flows from China’s Beijing-Tianjin-Hebei Urban Agglomeration to Northeast China,and then to Russia’s Far East Federal District.Relying on Suifenhe(China)and Hunchun(China),Primorsky No.1 and No.2 HSRs could be conducive to the development of the second largest sea channels for Northeast China,creating the Northeast Asian Urban Belt,and new sea-rail intermodal pattern among China,Russia,Democratic People’s Republic of Korea,Japan and Republic of Korea.Relying on Vladivostok(Russia)and Zarubino(Russia),Primorsky No.1 and No.2 corridors could connect the‘Ice Silk Road’,building the‘Sino-Russian Northern Maritime Corridor’and‘Sino-Russian Arctic Blue Economic Areas’.
基金supported by the National Natural Science Foundation of China(62202215)Liaoning Province Applied Basic Research Program(Youth Special Project,2023JH2/101600038)+2 种基金Shenyang Youth Science and Technology Innovation Talent Support Program(RC220458)Guangxuan Program of Shenyang Ligong University(SYLUGXRC202216)Basic Research Special Funds for Undergraduate Universities in Liaoning Province(LJ212410144067).
文摘The 6G smart Fog Radio Access Network(F-RAN)is an integration of 6G network intelligence technologies and the F-RAN architecture.Its aim is to provide low-latency and high-performance services for massive access devices.However,the performance of current 6G network intelligence technologies and its level of integration with the architecture,along with the system-level requirements for the number of access devices and limitations on energy consumption,have impeded further improvements in the 6G smart F-RAN.To better analyze the root causes of the network problems and promote the practical development of the network,this study used structured methods such as segmentation to conduct a review of the topic.The research results reveal that there are still many problems in the current 6G smart F-RAN.Future research directions and difficulties are also discussed.
文摘Attribute-based Encryption(ABE)enhances the confidentiality of Electronic Health Records(EHR)(also known as Personal Health Records(PHR))by binding access rights not to individual identities,but to user attribute sets such as roles,specialties,or certifications.This data-centric cryptographic paradigm enables highly fine-grained,policydriven access control,minimizing the need for identity management and supporting scalable multi-user scenarios.This paper presents a comprehensive and critical survey of ABE schemes developed specifically for EHR/PHR systems over the past decade.It explores the evolution of these schemes,analyzing their design principles,strengths,limitations,and the level of granularity they offer in access control.The review also evaluates the security guarantees,efficiency,and practical applicability of these schemes in real-world healthcare environments.Furthermore,the paper outlines the current state of ABE as a mechanism for safeguarding EHR data and managing user access,while also identifying the key challenges that remain.Open issues such as scalability,revocation mechanisms,policy updates,and interoperability are discussed in detail,providing valuable insights for researchers and practitioners aiming to advance the secure management of health information systems.
基金supported in part by the National Natural Science Foundation of China under grants 61771255in part by the Provincial and Ministerial Key Laboratory Open Project under grant 20190904in part by the Key Technologies R&D Program of Jiangsu (Prospective and Key Technologies for Industry)under Grants BE2022067,BE2022067-1 and BE2022067-2。
文摘High reliability applications in dense access scenarios have become one of the main goals of 6G environments.To solve the access collision of dense Machine Type Communication(MTC)devices in cell-free communication systems,an intelligent cooperative secure access scheme based on multi-agent reinforcement learning and federated learning is proposed,that is,the Preamble Slice Orderly Queue Access(PSOQA)scheme.In this scheme,the preamble arrangement is combined with the access control.The preamble arrangement is realized by preamble slices which is from the virtual preamble pool.The access devices learn to queue orderly by deep reinforcement learning.The orderly queue weakens the random and avoids collision.A preamble slice is assigned to an orderly access queue at each access time.The orderly queue is determined by interaction information among multiple agents.With the federated reinforcement learning framework,the PSOQA scheme is implemented to guarantee the privacy and security of agents.Finally,the access performance of PSOQA is compared with other random contention schemes in different load scenarios.Simulation results show that PSOQA can not only improve the access success rate but also guarantee low-latency tolerant performances.
基金supported in part by Jiangsu Province High Level“333”Program (0401206044)National Natural Science Foundation of China (61801243,62072255)+4 种基金Program for Scientific Research Foundation for Talented Scholars of Jinling Institute of Technology (JIT-B-202031)University Incubator Foundation of Jinling Institute of Technology (JIT-FHXM-202110)Open Project of Fujian Provincial Key Lab.of Network Security and Cryptology (NSCL-KF2021-02)Open Foundation of National Railway Intelligence Transportation System Engineering Tech.Research Center (RITS2021KF02)China Postdoctoral Science Foundation (2019M651914)。
文摘The secured access is studied in this paper for the network of the image remote sensing.Each sensor in this network encounters the information security when uploading information of the images wirelessly from the sensor to the central collection point.In order to enhance the sensing quality for the remote uploading,the passive reflection surface technique is employed.If one eavesdropper that exists nearby this sensor is keeping on accessing the same networks,he may receive the same image from this sensor.Our goal in this paper is to improve the SNR of legitimate collection unit while cut down the SNR of the eavesdropper as much as possible by adaptively adjust the uploading power from this sensor to enhance the security of the remote sensing images.In order to achieve this goal,the secured energy efficiency performance is theoretically analyzed with respect to the number of the passive reflection elements by calculating the instantaneous performance over the channel fading coefficients.Based on this theoretical result,the secured access is formulated as a mathematical optimization problem by adjusting the sensor uploading power as the unknown variables with the objective of the energy efficiency maximization while satisfying any required maximum data rate of the eavesdropper sensor.Finally,the analytical expression is theoretically derived for the optimum uploading power.Numerical simulations verify the design approach.
文摘BACKGROUND Central venous access is essential for administering chemotherapy in patients with gastrointestinal cancer.Peripherally inserted central catheters(PICC)and totally implantable venous access ports(TIVAP)are widely used,but comparative data regarding their impact on catheter-related complications and quality of life(QoL)remain limited.AIM To evaluate the impact of TIVAPs compared with PICC on catheter-related complications and QoL in patients with gastrointestinal cancer undergoing chemotherapy.METHODS This retrospective study included adults with gastrointestinal cancer who underwent central venous access device insertion for chemotherapy at our institution between December 2021 and December 2024.Inclusion criteria encompassed indications for intermittent intravenous chemotherapy,anticipated treatment duration of≥12 weeks,an adequate preoperative hematologic profile,accessible upper body veins,and complete medical records.Patients were excluded if they had an anticipated survival of less than three months,active systemic infection,severe thrombosis or coagulopathy,communication barriers,or an urgent need for dialysis access.Patients were assigned to either the PICC or TIVAP group based on device type.Data collected included demographic variables,cancer characteristics,insertion procedure details,complications,and QoL,assessed via the EuroQol 5-Dimensions-3 levels,visual analogue scale,and the European Organization for Research and Treatment of Cancer QoL Questionnaire-Core 30.RESULTS A total of 346 patients were analyzed.Baseline demographic,clinical,and cancer characteristics were similar between groups.The TIVAP group demonstrated a significantly lower incidence of catheter-related complications than the PICC group,with no pneumothorax occurring in either group.QoL assessments at baseline were comparable.At one month,the TIVAP group exhibited significantly higher EuroQoL Five Dimensions health state scores and QLQ-C30 global health status scores.Multivariate analysis identified TIVAP use,catheter tip placement in the distal superior vena cava/right atrium,prophylactic antibiotic administration,and antimicrobial dressing application as independent protective factors associated with reduced complications and improved QoL.CONCLUSION In patients with gastrointestinal cancer undergoing chemotherapy,TIVAPs are associated with a lower incidence of catheter-related complications and improved QoL than PICCs.Optimal device selection,precise catheter tip positioning,and effective perioperative management are critical for minimizing complications and enhancing patient-reported outcomes during treatment.
基金Supported by the Science and Technology Planning Project of Guangzhou,No.2024A03J0102the Natural Science Foundation of Guangdong Province for Distinguished Young Scholar,No.2022B1515020024+1 种基金National Natural Science Foundation of China,No.82070574the Key Research and Development Program of Guangzhou,No.2023B03J1298.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is notorious for its aggressive progression and dismal prognosis,with chromatin accessibility dynamics emerging as pivotal yet poorly understood drivers.AIM To dissect how multilayered chromatin regulation sustains oncogenic transcription and tumor-stroma crosstalk in HCC,we combined multiomics single cell analysis.METHODS We integrated single-cell RNA sequencing and paired single-cell assay for transposase-accessible chromatin with sequencing data of HCC samples,complemented by bulk RNA sequencing validation across The Cancer Genome Atlas,Liver Cancer Institute,and GSE25907 cohorts.Cell type-specific chromatin architectures were resolved via ArchR,with regulatory hubs identified through peak-to-gene linkages and coaccessibility networks.Functional validation employed A485-mediated histone 3 lysine 27 acetylation suppression and small interfering RNA targeting DGAT1.RESULTS Malignant hepatocytes exhibited expanded chromatin accessibility profiles,characterized by increased numbers of accessible peaks and larger physical regions despite reduced peak intensity.Enhancer-like peaks enriched in malignant regulation,forming long-range hubs.Eighteen enhancer-like peak-related genes showed tumor-specific overexpression and diagnostic accuracy,correlating with poor prognosis.Intercellular coaccessibility analysis revealed tumor-stroma symbiosis via shared chromatin states.Pharmacological histone 3 lysine 27 acetylation inhibition paradoxically downregulated DGAT1,the hub gene most strongly regulated by chromatin accessibility.DGAT1 knockdown suppressed cell proliferation.CONCLUSION Multilayered chromatin reprogramming sustains HCC progression through tumor-stroma crosstalk and DGAT1-related oncogenic transcription,defining targetable epigenetic vulnerabilities.
文摘The envisioned 6G wireless networks demand advanced Multiple Access (MA) schemes capable of supporting ultra-low latency, massive connectivity, high spectral efficiency, and energy efficiency (EE), especially as the current 5G networks have not achieved the promised 5G goals, including the projected 2000 times EE improvement over the legacy 4G Long Term Evolution (LTE) networks. This paper provides a comprehensive survey of Artificial Intelligence (AI)-enabled MA techniques, emphasizing their roles in Spectrum Sensing (SS), Dynamic Resource Allocation (DRA), user scheduling, interference mitigation, and protocol adaptation. In particular, we systematically analyze the progression of traditional and modern MA schemes, from Orthogonal Multiple Access (OMA)-based approaches like Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) to advanced Non-Orthogonal Multiple Access (NOMA) methods, including power domain-NOMA, Sparse Code Multiple Access (SCMA), and Rate Splitting Multiple Access (RSMA). The study further categorizes AI techniques—such as Machine Learning (ML), Deep Learning (DL), Reinforcement Learning (RL), Federated Learning (FL), and Explainable AI (XAI)—and maps them to practical challenges in Dynamic Spectrum Management (DSM), protocol optimization, and real-time distributed decision-making. Optimization strategies, including metaheuristics and multi-agent learning frameworks, are reviewed to illustrate the potential of AI in enhancing energy efficiency, system responsiveness, and cross-layer RA. Additionally, the review addresses security, privacy, and trust concerns, highlighting solutions like privacy-preserving ML, FL, and XAI in 6G and beyond. By identifying research gaps, challenges, and future directions, this work offers a structured resource for researchers and practitioners aiming to integrate AI into 6G MA systems for intelligent, scalable, and secure wireless communications.
基金Supported by the National Natural Science Foundation of China(No.60872041,61072066)Fundamental Research Funds for the Central Universities(JYI0000903001,JYI0000901034)
文摘To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put forward to calculate the uncertainty of the system' s determinations on the irregular access behaviors.Secondly,based on the security entropy,security theorems of hybrid cloud are defined.Finally,typical access control models are analyzed by the method,the method's practicability is validated,and security and applicability of these models are compared.Simulation results prove that the proposed method is suitable for the security quantitative analysis of the access control model and evaluation to access control capability in hybrid cloud.
