Cerebral small vessel disease encompasses a group of neurological disorders characterized by injury to small blood vessels,often leading to stroke and dementia.Due to its diverse etiologies and complex pathological me...Cerebral small vessel disease encompasses a group of neurological disorders characterized by injury to small blood vessels,often leading to stroke and dementia.Due to its diverse etiologies and complex pathological mechanisms,preventing and treating cerebral small vessel vasculopathy is challenging.Recent studies have shown that the glymphatic system plays a crucial role in interstitial solute clearance and the maintenance of brain homeostasis.Increasing evidence also suggests that dysfunction in glymphatic clearance is a key factor in the progression of cerebral small vessel disease.This review begins with a comprehensive introduction to the structure,function,and driving factors of the glymphatic system,highlighting its essential role in brain waste clearance.Afterwards,cerebral small vessel disease was reviewed from the perspective of the glymphatic system,after which the mechanisms underlying their correlation were summarized.Glymphatic dysfunction may lead to the accumulation of metabolic waste in the brain,thereby exacerbating the pathological processes associated with cerebral small vessel disease.The review also discussed the direct evidence of glymphatic dysfunction in patients and animal models exhibiting two subtypes of cerebral small vessel disease:arteriolosclerosis-related cerebral small vessel disease and amyloid-related cerebral small vessel disease.Diffusion tensor image analysis along the perivascular space is an important non-invasive tool for assessing the clearance function of the glymphatic system.However,the effectiveness of its parameters needs to be enhanced.Among various nervous system diseases,including cerebral small vessel disease,glymphatic failure may be a common final pathway toward dementia.Overall,this review summarizes prevention and treatment strategies that target glymphatic drainage and will offer valuable insight for developing novel treatments for cerebral small vessel disease.展开更多
Background:The traditional method of heterotopic abdominal heart transplantation(HTx)involves crossclamping the inferior vena cava,which inevitably leads to bilateral lower limb ischemia(LI).This study first aimed to ...Background:The traditional method of heterotopic abdominal heart transplantation(HTx)involves crossclamping the inferior vena cava,which inevitably leads to bilateral lower limb ischemia(LI).This study first aimed to investigate the impact of LI on renal function in rats subjected to unilateral nephrectomy(UNx).Second,a modified method utilizing renal vessel-assisted anastomosis in rats with left UNx was compared with the traditional method for abdominal HTx.Methods:Male Sprague-Dawley rats were utilized as subjects for both experimental phases.In experiment 1,the animals were divided into four groups:sham operation group;LI group-rats undergoing occlusion of the abdominal aorta and vena cava below the renal vessels;UNx group-rats with left UNx;and LI+UNx group.All operated animals were monitored for up to 7 days for biochemical markers,renal histopathology,and survival rates.In experiment 2,we introduced the renal vessel-assisted method as the experimental group and compared it against the traditional method as the control within rat heterotopic HTx models.We assessed operative characteristics,echocardiography results,histological findings,and graft survival.Results:First,LI resulted in acute kidney dysfunction characterized by a decrease in 7day survival rates and creatinine clearance rates in both the LI and LI+UNx groups compared to the sham operation and UNx groups.Particularly,histopathological damage in the kidney and liver did not exhibit significant effects during this period.Second,the implementation of the renal vessel-assisted method significantly reduced bleeding volume at suture sites and enhanced the 7day survival rate compared to the traditional method.Conclusion:Acute kidney injury was induced by LI postoperation in treated rats.The renal vessel-assisted method demonstrated its effectiveness as a superior alternative that mitigates complications associated with the traditional method.展开更多
Each morning at Yangluo Port in Wuhan,Hubei Province,the all-electric cargo vessel Huahang Xinneng No.1 completes a battery swap in under 10 minutes before returning to service with nearly 8,000 kWh of power onboard。
Cerebral small vessel disease is a major vascular contributor to cognitive impairment and dementia.However,there remains a lack of effective preventative or therapeutic regimens for cerebral small vessel disease.In th...Cerebral small vessel disease is a major vascular contributor to cognitive impairment and dementia.However,there remains a lack of effective preventative or therapeutic regimens for cerebral small vessel disease.In this study,we investigated the potential therapeutic effects of MCC950,a selective NOD-like receptor family pyrin domain-containing protein 3 inhibitor,on cerebral small vessel disease pathogenesis and cognitive decline in spontaneously hypertensive rats.Our results showed that chronic administration of MCC950(10 mg/kg)to spontaneously hypertensive rats inhibited NOD-like receptor family pyrin domain-containing protein 3 inflammasome activation,thereby considerably suppressing the production of pyroptosis executive protein gasdermin D and pro-inflammatory factors,including interleukin-1βand-18.A decrease in astrocytic and microglial activation was also observed.We also found that MCC950 significantly inhibited autophagy.More importantly,behavioral assessment indicated that MCC950 administration ameliorated impaired neurocognitive function,which was associated with improvements in neuropathological hallmarks in the cerebral small vessel disease brain,such as blood‒brain barrier breakdown,white matter damage,and endothelial dysfunction.Thus,our findings revealed that the NOD-like receptor family pyrin domain-containing protein 3 inflammasome is a key contributor to the onset or progression of cerebral small vessel disease and suggested the potential of NOD-like receptor family pyrin domain-containing protein 3-based therapy as a potential novel strategy for treating cerebral small vessel disease.展开更多
To conduct marine surveys,multiple unmanned surface vessels(Multi-USV)with different capabilities perform collaborative mapping in multiple designated areas.This paper proposes a task allocation algorithm based on int...To conduct marine surveys,multiple unmanned surface vessels(Multi-USV)with different capabilities perform collaborative mapping in multiple designated areas.This paper proposes a task allocation algorithm based on integer linear programming(ILP)with flow balance constraints,ensuring the fair and efficient distribution of sub-areas among USVs and maintaining strong connectivity of assigned regions.In the established gridmap,a search-based path planning algorithm is performed on the sub-areas according to the allocation scheme.It uses the greedy algorithm and the A*algorithm to achieve complete coverage of the barrier-free area and obtain an efficient trajectory of each USV.The greedy algorithm enables fast local traversal of unvisited grids,while the A*algorithm ensures navigation to escape from deadlock areas and maintains global path continuity.The comparison of task allocation results proves that the task allocation algorithm based on ILP improves the mapping efficiency and task distribution fairness.The proposed allocation method and result analysis provide a certain reference for the practical application ofMulti-USV to perform survey tasks collaboratively.展开更多
Analysis of the environmental and economic performance of fishing vessels has received limited attention compared with other ship types despite their notable contribution to global greenhouse gas(GHG)emissions.This st...Analysis of the environmental and economic performance of fishing vessels has received limited attention compared with other ship types despite their notable contribution to global greenhouse gas(GHG)emissions.This study evaluates the carbon footprint(CF)and economic viability of a liquefied natural gas(LNG)-fueled fishing vessel,using real engine operation simulations to provide precise and dynamic evaluation of fuel consumption and GHG emissions.Operational profiles are obtained through the utilization of onboard monitoring systems,whereas engine performance is simulated using the 1D/0D AVL Boost^(TM)model.Life cycle assessment(LCA)is conducted to quantify the environmental impact,whereas life cycle cost assessment(LCCA)is performed to analyze the profitability of LNG as an alternative fuel.The potential impact of the future fuel price uncertainties is addressed using Monte Carlo simulations.The LCA findings indicate that LNG has the potential to reduce the CF of the vessel by 14%to 16%,in comparison to a diesel power system configuration that serves as the baseline scenario.The LCCA results further indicate that the total cost of an LNG-powered ship is lower by 9.5%-13.8%,depending on the share of LNG and pilot fuels.This finding highlights the potential of LNG to produce considerable environmental benefits while addressing economic challenges under diverse operational and fuel price conditions.展开更多
Dear Editor,Underactuated autonomous surface vessels(ASVs)are increasingly attracting attention from researchers because of a wide range of applications[1].Consequently,path following,a typical functionality for ASVs,...Dear Editor,Underactuated autonomous surface vessels(ASVs)are increasingly attracting attention from researchers because of a wide range of applications[1].Consequently,path following,a typical functionality for ASVs,has become a research focus[2].Despite the abundant study results,some challenging issues are still worthy of exploration and resolution,two of which are addressed in this letter.The first one is related to the guidance law.Currently,common guidance methods in the ASV field include the line-of-sight(LOS)guidance[3]and vector field(VF)guidance[4].The response quality of LOS guidance is highly related to the lookahead distance;a constant lookahead distance may result in undesired phenomena such as the singularity problem and the reduction of trajectory smoothness of ASVs(see[5]).To this end,several works have proposed modified LOS guidance laws(see[6]).Although the above modifications,as pointed out by[7],the VF guidance exhibits smaller crosstrack errors and better performances than the LOS guidance.However,the existing VF guidance is only available for straight lines and orbits rather than curved paths,a considerable obstacle that limits its practical application(see[8],[9]).Thus,the VF guidance for curved path following deserves more in-depth study.展开更多
Meningeal lymphatic vessels form a relationship between the nervous system and periphery, which is relevant in both health and disease. Meningeal lymphatic vessels not only play a key role in the drainage of brain met...Meningeal lymphatic vessels form a relationship between the nervous system and periphery, which is relevant in both health and disease. Meningeal lymphatic vessels not only play a key role in the drainage of brain metabolites but also contribute to antigen delivery and immune cell activation. The advent of novel genomic technologies has enabled rapid progress in the characterization of myeloid and lymphoid cells and their interactions with meningeal lymphatic vessels within the central nervous system. In this review, we provide an overview of the multifaceted roles of meningeal lymphatic vessels within the context of the central nervous system immune network, highlighting recent discoveries on the immunological niche provided by meningeal lymphatic vessels. Furthermore, we delve into the mechanisms of crosstalk between meningeal lymphatic vessels and immune cells in the central nervous system under both homeostatic conditions and neurodegenerative diseases, discussing how these interactions shape the pathological outcomes. Regulation of meningeal lymphatic vessel function and structure can influence lymphatic drainage, cerebrospinal fluid-borne immune modulators, and immune cell populations in aging and neurodegenerative disorders, thereby playing a key role in shaping meningeal and brain parenchyma immunity.展开更多
Cardiovascular disease(CVD)is a major global health challenge,which causes significant illness and death worldwide.These include a range of conditions that affect the heart and blood vessels,including coro-nary artery...Cardiovascular disease(CVD)is a major global health challenge,which causes significant illness and death worldwide.These include a range of conditions that affect the heart and blood vessels,including coro-nary artery disease,stroke,peripheral artery disease,and heart failure.Despite advances in medicine and healthcare delivery,CVD continues to have a serious impact on individuals,families,and the healthcare system.This review begins by delineating the merits and demerits of commonly employed synthetic and natural materials for artificial blood vessels.It delves into various techniques commonly employed in the fabrication of artificial blood vessels,encompassing advanced textile technologies,electrospinning,ther-mally induced phase separation,and 3D printing.The review critically analyzes the attributes of different preparation methodologies alongside the latest advancements in research.The review also outlines the requisite performance requirements for artificial blood vessels,which encompass robust mechanical prop-erties,appropriate porosity,exceptional compatibility,and antibacterial attributes.It provides a succinct overview of ongoing effort s in vascular functionalization,particularly emphasizing thrombus mitigation,promotion of endothelialization,and enhancement of nitric oxide production.The review finally encap-sulates the primary challenges confronting vascular grafts and prospective avenues for future research.展开更多
Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited t...Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited training data,imbalance data distribution,and inadequate feature extraction persist,hindering both the segmentation performance and optimal model generalization.Addressing these critical issues,the DEFFA-Unet is proposed featuring an additional encoder to process domain-invariant pre-processed inputs,thereby improving both richer feature encoding and enhanced model generalization.A feature filtering fusion module is developed to ensure the precise feature filtering and robust hybrid feature fusion.In response to the task-specific need for higher precision where false positives are very costly,traditional skip connections are replaced with the attention-guided feature reconstructing fusion module.Additionally,innovative data augmentation and balancing methods are proposed to counter data scarcity and distribution imbalance,further boosting the robustness and generalization of the model.With a comprehensive suite of evaluation metrics,extensive validations on four benchmark datasets(DRIVE,CHASEDB1,STARE,and HRF)and an SLO dataset(IOSTAR),demonstrate the proposed method’s superiority over both baseline and state-of-the-art models.Particularly the proposed method significantly outperforms the compared methods in cross-validation model generalization.展开更多
Objective To explore the effect of electroacupuncture at conception vessel and governor vessel on correlative signals of inflammatory response stressinjury-repair in cerebral ischemia reperfusion rats. Methods A total...Objective To explore the effect of electroacupuncture at conception vessel and governor vessel on correlative signals of inflammatory response stressinjury-repair in cerebral ischemia reperfusion rats. Methods A total of 216 rats were included in the experiment, of which 192 rats were randomly divided into four groups, including sham operation group（group A）, model group（group B）, governor vessel group（group C）, and conception vessel and governor vessel group（group D）, 48 rats in each group. The rats in each group were further divided into six sub-groups, including 12 h group, 24 h group, 48 h group, 72 h group, 96 h group and 144 h group. MCAO operation course was simulated in group A, and the common carotid artery, internal carotid artery and external carotid artery on the right side were exposed, without insertion of suture or treatment. After completion of modeling in group B, treatment was not conducted. After completion of modeling in group C, ＂Shuǐgōu（水沟 GV 26）＂, ＂Bǎihuì（百会 GV 20）＂ and ＂Dàzhuī（大椎 GV 14）＂ of governor vessel were selected, and electroacupuncture device was connected with ＂GV 14＂ and ＂GV 20＂. After completion of modeling in group D, ＂GV 26＂, ＂GV 20＂ and ＂GV 14＂ of governor vessel, and ＂Qìhǎi（气海 CV 6）＂, ＂Guānyuán（关元 CV 4）＂ and ＂Chéngjiāng（承浆 CV 24）＂ of conception vessel were selected; electroacupuncture device was connected with ＂GV 14＂ and ＂GV 20＂, ＂CV 4＂ and ＂CV 6＂. Neurological severity score was conducted.Enzyme linked immunosorbent assay（ELISA） was applied to determine the concentration of peripheral serum adrenocorticotropic hormone（ACTH） of rats, and immunohistochemical method was adopted to detect the expression levels of tumor necrosis factor α（TNF-α） and transforming growth factor β1（TGF-β1） in brain tissue of rats. The other 24 rats were also randomly divided into four groups mentioned above, 6 rats in each group, to detect cerebral ischemie volume. Results Compared with group B, the ischemia volume in brain tissue at 144 h after cerebral ischemia reperfusion decreased significantly in group C and group D（P〈0.05）, and the ischemia volume in group D was less than that in group C（P〈0.05）. The neurological impairment scores of group C and group D at all time points were lower than those of group B, and the differences were statistically significant（all P〈0.05）. The scores of group D at all time points were lower than those of group C, and the differences since 24 h were statistically significant（all P〈0.05）. Compared with group B, the excessive expression of ACTH was suppressed dynamically and generally in group C and group D（P〈0.05）; the expression level of TNF-α was down-regulated and TGF-β1 was up-regulated as well in group C and group D（P〈0.05）. The effect in group D was superior to that in group C. Conclusion Electroacupuncture at conception vessel and governor vessel can protect brain through the intervention of the expression of correlative signals of inflammatory response stress-injury-repair of cerebral ischemia reperfusion.展开更多
As a vessel navigates at high speeds in waves,considerable pitching motion can result in the discomfort of passengers.In this study is proposed a ride control system consisting of dual T-foils to generate a larger rig...As a vessel navigates at high speeds in waves,considerable pitching motion can result in the discomfort of passengers.In this study is proposed a ride control system consisting of dual T-foils to generate a larger righting moment than a common single T-foil system.One T-foil is mounted at the bow,and the other at the stern.Accordingly,different control strategies for dual T-foils were proposed To verify the stratigies,a model experiment was conducted in the Towing Tank,Dalian Unievrsity of Technology.The optimal control signal was determined by comparing the pitch responses,heave responses,bow accelerations,and stern accelerations of a vessel in regular waves.In addition,the control strategy for the best motion-reduction effect was investigated.The optimized dual T-foil system provides a 34%reduction in pitch motion.展开更多
As global efforts to combat climate change intensify,offshore wind farms have emerged as scalable and sustainable solutions.However,their deployment depends heavily on the availability of specialized vessels with Dyna...As global efforts to combat climate change intensify,offshore wind farms have emerged as scalable and sustainable solutions.However,their deployment depends heavily on the availability of specialized vessels with Dynamic Positioning(DP)systems such as Wind Turbine Installation Vessels(WTIVs)and Service Operation Vessels(SOVs).Despite their importance,long-term demand forecasting for such vessels remains underexplored,especially in South Korea.This study presents the dDP-W model,a System Dynamics(SD)-based framework that simulates the evolving demand for DP vessels under varying technological,policy,and environmental conditions.Unlike conventional methods based on historical extrapolation,the model uses feedback-driven causality and scenario-based simulations aligned with South Korea’s offshore wind roadmap(2026-2036).Three WTIV demand scenarios—baseline,optimistic,and pessimistic—were constructed based on vessel productivity and weather-related downtime.SOV demand was estimated using cumulative turbine counts and fixed vessel coverage ratios.The simulations indicate that WTIV demand peaks in the early 2030s,requiring 6 to 7 vessels depending on conditions,while SOV demand increases steadily,reaching nearly 70 vessels by 2036.These findings highlight the need for early vessel procurement,infrastructure investment,and workforce preparation.By integrating technical,logistical,and policy factors into a dynamic model,this study provides a practical decision-support tool for stakeholders in shipbuilding and offshore energy.The results offer strategic insights to address potential vessel shortages and ensure alignment with national renewable energy goals.展开更多
AIM:To compare the effects of different types of negative pressure suction on the macular and optic disc retinal vessel density(VD)in myopic patients with different axial lengths(ALs)undergoing femtosecond laser-assis...AIM:To compare the effects of different types of negative pressure suction on the macular and optic disc retinal vessel density(VD)in myopic patients with different axial lengths(ALs)undergoing femtosecond laser-assisted excimer laser in situ keratomileusis(FS-LASIK)by optical coherence tomography angiography(OCTA).METHODS:A prospective,nonrandomized,controlled study.Participants underwent FS-LASIK surgery were divided into the short AL group(SAL,22≤AL<26 mm)and the long AL group(LAL,26≤AL<28 mm)according to the different ALs.Further,the two groups were divided into subgroups according to the corneal flap using VisuMax or WaveLight FS200 femtosecond laser(FS)platform.All patients underwent OCTA before the surgery and 1-day/1-week/1-month after the surgery.ANOVA statistically analyzed data with two-factor repeated measurement in SPSS.RESULTS:Totally 108 participants(108 eyes,18–35y)were divided into SAL group[22 patients(4 males and 18 females)were treated with VisuMax,and 24(3 males and 21 females)were treated with WaveLight FS200]and LAL group[34 patients(4 males and 30 females)were treated with VisuMax,and 28 patients(6 males and 22 females)were treated with WaveLight FS200].In the LAL group,there was no significant difference in macular superficial capillary plexuses vessel density(SCP-VD)in the fovea and perifovea region,but compared with the VisuMax subgroup,SCP-VD in the parafoveal region(t=2.647,P=0.010)and the whole area(t=2.030,P=0.047)in WaveLight FS200 subgroup decreased at one day after the operation and increased to a preoperative level at 1-week and 1-month after operation.There was no significant difference between SCP-VD in the two SAL subgroups,neither of deep capillary plexuses vessel density(DCP-VD)and optic nerve head vessel density(ONH-VD)in the SAL and LAL groups.CONCLUSION:With the increase of AL and suction intensity,a transient decrease of SCP-VD in the macular region is observed at 1d postoperatively during FS-LASIK,and it increases to preoperative level at 1-week and 1-month postoperatively.However,the AL and suction intensity do not affect the macular DCP-VD and ONH-VD.展开更多
Since the problems of branch loss and fracture in retinal blood vessel segmentation algorithms,an image segmentation method is proposed based on improved pulse coupled neural network(PCNN)and gray wolf optimization al...Since the problems of branch loss and fracture in retinal blood vessel segmentation algorithms,an image segmentation method is proposed based on improved pulse coupled neural network(PCNN)and gray wolf optimization algorithm(GWO).Simplifying the neuron input domain and neuron connection domain of the PCNN network,increasing the gradient information factor in the internal activity items,reducing the model parameters,enhancing the pulse issuing ability,and the optimal parameters of the network are automatically obtained based on multiple feature evaluation criteria and the GWO algorithm.The test in the public data set drive shows that the sensitivity,accuracy,precision,and specificity of the algorithm are 0.799549,0.962789,0.889163,and 0.986552,respectively.The accuracy and specificity are better than the classical segmentation algorithm.It solved the influence of low illumination,optic disc highlight,and foveal shadow on vascular segmentation,and showed excellent performance of vessel connectivity and terminal sensitivity.展开更多
The mechanical properties,microstructure and second phase precipitation behavior of flange forgings for high-pressure hydrogen storage vessels at different tempering temperatures(620–700℃)were studied.The results sh...The mechanical properties,microstructure and second phase precipitation behavior of flange forgings for high-pressure hydrogen storage vessels at different tempering temperatures(620–700℃)were studied.The results showed that when tempered at 620–680°C,the main microstructure of the test steel was tempered sorbite,and the main microstructure of tempered steel changed to martensite at 700℃.At 700℃,the dislocation density increased and some retained austenite existed.With the tempering temperature increasing,the yield strength showed a decreasing trend,the formation of fresh martensite made the tensile strength first decrease and then increase slightly,the impact energy at−40℃increased first and then decreased,and the impact energy at 660℃had the maximum value.The precipitates of MC type were mainly(Mo,V,Ti)C.The test steel had excellent strength and toughness matching at 660℃tempering,the tensile strength at different cross section locations was above 750 MPa,the impact energy was above 200 J at−40℃,and the relative percentage reduction of area(ZH2/ZN2)was above 75%at hydrogen environment of 6.3 MPa.展开更多
Objective:To study the application effect of bundle nursing strategy in the maintenance of difficult blood vessels for long-term hemodialysis patients.Methods:A prospective study was conducted on 40 long-term hemodial...Objective:To study the application effect of bundle nursing strategy in the maintenance of difficult blood vessels for long-term hemodialysis patients.Methods:A prospective study was conducted on 40 long-term hemodialysis patients admitted from January 2024 to January 2025.The patients were randomly divided into a control group(20 cases)and an observation group(20 cases)using computer random sampling.The control group received routine nursing for difficult blood vessels,while the observation group received a bundle nursing strategy for difficult blood vessels.The self-care ability,complication rate,and nursing satisfaction were compared between the two groups.Results:After nursing,the self-care ability score of the observation group was higher than that of the control group(P<0.05).The complication rate in the observation group was lower than that in the control group(P<0.05).The nursing satisfaction in the observation group was higher than that in the control group(P<0.05).Conclusion:The application of the bundle nursing strategy in the maintenance of difficult blood vessels for long-term hemodialysis patients is beneficial for improving self-care ability,reducing complications,and increasing patient satisfaction with nursing services.展开更多
The segmentation of retinal vessels and coronary angiographs is essential for diagnosing conditions such as glaucoma,diabetes,hypertension,and coronary artery disease.However,retinal vessels and coronary angiographs a...The segmentation of retinal vessels and coronary angiographs is essential for diagnosing conditions such as glaucoma,diabetes,hypertension,and coronary artery disease.However,retinal vessels and coronary angiographs are characterized by low contrast and complex structures,posing challenges for vessel segmentation.Moreover,CNN-based approaches are limited in capturing long-range pixel relationships due to their focus on local feature extraction,while ViT-based approaches struggle to capture fine local details,impacting tasks like vessel segmentation that require precise boundary detection.To address these issues,in this paper,we propose a Global–Local Hybrid Modulation Network(GLHM-Net),a dual-encoder architecture that combines the strengths of CNNs and ViTs for vessel segmentation.First,the Hybrid Non-Local Transformer Block(HNLTB)is proposed to efficiently consolidate long-range spatial dependencies into a compact feature representation,providing a global perspective while significantly reducing computational overhead.Second,the Collaborative Attention Fusion Block(CAFB)is proposed to more effectively integrate local and global vessel features at the same hierarchical level during the encoding phase.Finally,the proposed Feature Cross-Modulation Block(FCMB)better complements the local and global features in the decoding stage,effectively enhancing feature learning and minimizing information loss.The experiments conducted on the DRIVE,CHASEDB1,DCA1,and XCAD datasets,achieving AUC values of 0.9811,0.9864,0.9915,and 0.9919,F1 scores of 0.8288,0.8202,0.8040,and 0.8150,and IOU values of 0.7076,0.6952,0.6723,and 0.6878,respectively,demonstrate the strong performance of our proposed network for vessel segmentation.展开更多
Tensile deformation and microvoid formation of quenched and tempered SA508 Gr.3 steel were studied using an in-situ digital image correlation technique and in-situ electron backscatter diffraction(EBSD)measurements.Th...Tensile deformation and microvoid formation of quenched and tempered SA508 Gr.3 steel were studied using an in-situ digital image correlation technique and in-situ electron backscatter diffraction(EBSD)measurements.The quenched steel with a mixture of up-per bainite and granular bainite exhibited a high ultimate tensile strength(UTS)of~795 MPa and an elongation of~25%.After temper-ing,long-rod carbides and accumulated carbide particles were formed at the interface of bainite–ferrite subunits and prior austenite grain boundaries(PAGBs),respectively.The UTS of the tempered steel decreased to~607 MPa,whereas the total elongation increased to 33.0%with a local strain of 191.0%at the necked area.In-situ EBSD results showed that strain localization in the bainite–ferrite pro-duced lattice rotation and dislocation pileup,thus leading to stress concentration at the discontinuities(e.g.,martensite–austenite islands and carbides).Consequently,the decohesion of PAGBs dotted with martensite–austenite islands was the dominant microvoid initiation mechanism in the quenched steel,whereas microvoids primarily initiated through the fracturing of long-rod carbides and the decohesion of PAGBs with carbides aggregation in the tempered steel.The fracture surfaces for both the quenched and tempered specimens featured dimples,indicating the ductile failure mechanism caused by microvoid coalescence.展开更多
To address low detection accuracy in near-coastal vessel target detection under complex conditions,a novel near-coastal vessel detection model based on an improved YOLOv7 architecture is proposed in this paper.The att...To address low detection accuracy in near-coastal vessel target detection under complex conditions,a novel near-coastal vessel detection model based on an improved YOLOv7 architecture is proposed in this paper.The attention mechanism Coordinate Attention is used to improve channel attention weight and enhance a network’s ability to extract small target features.In the enhanced feature extraction network,the lightweight convolution algorithm Grouped Spatial Convolution is used to replace MPConv to reduce model calculation costs.EIoU Loss is used to replace the regression frame loss function in YOLOv7 to reduce the probability of missed and false detection.The performance of the improved model was verified using an enhanced dataset obtained through rainy and foggy weather simulation.Experiments were conducted on the datasets before and after the enhancement.The improved model achieved a mean average precision(mAP)of 97.45%on the original dataset,and the number of parameters was reduced by 2%.On the enhanced dataset,the mAP of the improved model reached 88.08%.Compared with seven target detection models,such as Faster R-CNN,YOLOv3,YOLOv4,YOLOv5,YOLOv7,YOLOv8-n,and YOLOv8-s,the improved model can effectively reduce the missed and false detection rates and improve target detection accuracy.The improved model not only accurately detects vessels in complex weather environments but also outperforms other methods on original and enhanced SeaShip datasets.This finding shows that the improved model can achieve near-coastal vessel target detection in multiple environments,laying the foundation for vessel path planning and automatic obstacle avoidance.展开更多
基金supported by the National Natural Science Foundation of China,No.82274304(to YH)the Major Clinical Study Projects of Shanghai Shenkang Hospital Development Center,No.SHDC2020CR2046B(to YH)Shanghai Municipal Health Commission Talent Plan,No.2022LJ010(to YH).
文摘Cerebral small vessel disease encompasses a group of neurological disorders characterized by injury to small blood vessels,often leading to stroke and dementia.Due to its diverse etiologies and complex pathological mechanisms,preventing and treating cerebral small vessel vasculopathy is challenging.Recent studies have shown that the glymphatic system plays a crucial role in interstitial solute clearance and the maintenance of brain homeostasis.Increasing evidence also suggests that dysfunction in glymphatic clearance is a key factor in the progression of cerebral small vessel disease.This review begins with a comprehensive introduction to the structure,function,and driving factors of the glymphatic system,highlighting its essential role in brain waste clearance.Afterwards,cerebral small vessel disease was reviewed from the perspective of the glymphatic system,after which the mechanisms underlying their correlation were summarized.Glymphatic dysfunction may lead to the accumulation of metabolic waste in the brain,thereby exacerbating the pathological processes associated with cerebral small vessel disease.The review also discussed the direct evidence of glymphatic dysfunction in patients and animal models exhibiting two subtypes of cerebral small vessel disease:arteriolosclerosis-related cerebral small vessel disease and amyloid-related cerebral small vessel disease.Diffusion tensor image analysis along the perivascular space is an important non-invasive tool for assessing the clearance function of the glymphatic system.However,the effectiveness of its parameters needs to be enhanced.Among various nervous system diseases,including cerebral small vessel disease,glymphatic failure may be a common final pathway toward dementia.Overall,this review summarizes prevention and treatment strategies that target glymphatic drainage and will offer valuable insight for developing novel treatments for cerebral small vessel disease.
基金The Youth Project of Tianjin Natural Science Foundation,Grant/Award Number:23JCQNJC01380。
文摘Background:The traditional method of heterotopic abdominal heart transplantation(HTx)involves crossclamping the inferior vena cava,which inevitably leads to bilateral lower limb ischemia(LI).This study first aimed to investigate the impact of LI on renal function in rats subjected to unilateral nephrectomy(UNx).Second,a modified method utilizing renal vessel-assisted anastomosis in rats with left UNx was compared with the traditional method for abdominal HTx.Methods:Male Sprague-Dawley rats were utilized as subjects for both experimental phases.In experiment 1,the animals were divided into four groups:sham operation group;LI group-rats undergoing occlusion of the abdominal aorta and vena cava below the renal vessels;UNx group-rats with left UNx;and LI+UNx group.All operated animals were monitored for up to 7 days for biochemical markers,renal histopathology,and survival rates.In experiment 2,we introduced the renal vessel-assisted method as the experimental group and compared it against the traditional method as the control within rat heterotopic HTx models.We assessed operative characteristics,echocardiography results,histological findings,and graft survival.Results:First,LI resulted in acute kidney dysfunction characterized by a decrease in 7day survival rates and creatinine clearance rates in both the LI and LI+UNx groups compared to the sham operation and UNx groups.Particularly,histopathological damage in the kidney and liver did not exhibit significant effects during this period.Second,the implementation of the renal vessel-assisted method significantly reduced bleeding volume at suture sites and enhanced the 7day survival rate compared to the traditional method.Conclusion:Acute kidney injury was induced by LI postoperation in treated rats.The renal vessel-assisted method demonstrated its effectiveness as a superior alternative that mitigates complications associated with the traditional method.
文摘Each morning at Yangluo Port in Wuhan,Hubei Province,the all-electric cargo vessel Huahang Xinneng No.1 completes a battery swap in under 10 minutes before returning to service with nearly 8,000 kWh of power onboard。
基金supported by the National Natural Science Foundation of China,No.82201626(to CC)the Natural Science Foundation of LiaoningProvince,No.2022-MS-442(to CC)the Dalian Municipal Medical Key Specialty Climbing Project,No.2024ZZ040(to MZ).
文摘Cerebral small vessel disease is a major vascular contributor to cognitive impairment and dementia.However,there remains a lack of effective preventative or therapeutic regimens for cerebral small vessel disease.In this study,we investigated the potential therapeutic effects of MCC950,a selective NOD-like receptor family pyrin domain-containing protein 3 inhibitor,on cerebral small vessel disease pathogenesis and cognitive decline in spontaneously hypertensive rats.Our results showed that chronic administration of MCC950(10 mg/kg)to spontaneously hypertensive rats inhibited NOD-like receptor family pyrin domain-containing protein 3 inflammasome activation,thereby considerably suppressing the production of pyroptosis executive protein gasdermin D and pro-inflammatory factors,including interleukin-1βand-18.A decrease in astrocytic and microglial activation was also observed.We also found that MCC950 significantly inhibited autophagy.More importantly,behavioral assessment indicated that MCC950 administration ameliorated impaired neurocognitive function,which was associated with improvements in neuropathological hallmarks in the cerebral small vessel disease brain,such as blood‒brain barrier breakdown,white matter damage,and endothelial dysfunction.Thus,our findings revealed that the NOD-like receptor family pyrin domain-containing protein 3 inflammasome is a key contributor to the onset or progression of cerebral small vessel disease and suggested the potential of NOD-like receptor family pyrin domain-containing protein 3-based therapy as a potential novel strategy for treating cerebral small vessel disease.
基金supported in part by the International Science and Technology Project of Guangzhou Development District under Grant 2023GH08the Science and Technology Development Fund,MSAR,under Grants 0029/2022/AGJ and 0029/2023/RIA1the Program of Guangdong under Grant 2023A0505020003.
文摘To conduct marine surveys,multiple unmanned surface vessels(Multi-USV)with different capabilities perform collaborative mapping in multiple designated areas.This paper proposes a task allocation algorithm based on integer linear programming(ILP)with flow balance constraints,ensuring the fair and efficient distribution of sub-areas among USVs and maintaining strong connectivity of assigned regions.In the established gridmap,a search-based path planning algorithm is performed on the sub-areas according to the allocation scheme.It uses the greedy algorithm and the A*algorithm to achieve complete coverage of the barrier-free area and obtain an efficient trajectory of each USV.The greedy algorithm enables fast local traversal of unvisited grids,while the A*algorithm ensures navigation to escape from deadlock areas and maintains global path continuity.The comparison of task allocation results proves that the task allocation algorithm based on ILP improves the mapping efficiency and task distribution fairness.The proposed allocation method and result analysis provide a certain reference for the practical application ofMulti-USV to perform survey tasks collaboratively.
文摘Analysis of the environmental and economic performance of fishing vessels has received limited attention compared with other ship types despite their notable contribution to global greenhouse gas(GHG)emissions.This study evaluates the carbon footprint(CF)and economic viability of a liquefied natural gas(LNG)-fueled fishing vessel,using real engine operation simulations to provide precise and dynamic evaluation of fuel consumption and GHG emissions.Operational profiles are obtained through the utilization of onboard monitoring systems,whereas engine performance is simulated using the 1D/0D AVL Boost^(TM)model.Life cycle assessment(LCA)is conducted to quantify the environmental impact,whereas life cycle cost assessment(LCCA)is performed to analyze the profitability of LNG as an alternative fuel.The potential impact of the future fuel price uncertainties is addressed using Monte Carlo simulations.The LCA findings indicate that LNG has the potential to reduce the CF of the vessel by 14%to 16%,in comparison to a diesel power system configuration that serves as the baseline scenario.The LCCA results further indicate that the total cost of an LNG-powered ship is lower by 9.5%-13.8%,depending on the share of LNG and pilot fuels.This finding highlights the potential of LNG to produce considerable environmental benefits while addressing economic challenges under diverse operational and fuel price conditions.
基金supported by the National Natural Science Foundation of China(62473243,62421004)the Fundamental Research Funds for the Provincial Universities(3072024 GH0404)+1 种基金the Key Research and Development Projects in Hainan Province(ZDYF2024GXJS009)the“Spring Wild Goose”Plan Project of Heilongjiang Province(CYQN24071).
文摘Dear Editor,Underactuated autonomous surface vessels(ASVs)are increasingly attracting attention from researchers because of a wide range of applications[1].Consequently,path following,a typical functionality for ASVs,has become a research focus[2].Despite the abundant study results,some challenging issues are still worthy of exploration and resolution,two of which are addressed in this letter.The first one is related to the guidance law.Currently,common guidance methods in the ASV field include the line-of-sight(LOS)guidance[3]and vector field(VF)guidance[4].The response quality of LOS guidance is highly related to the lookahead distance;a constant lookahead distance may result in undesired phenomena such as the singularity problem and the reduction of trajectory smoothness of ASVs(see[5]).To this end,several works have proposed modified LOS guidance laws(see[6]).Although the above modifications,as pointed out by[7],the VF guidance exhibits smaller crosstrack errors and better performances than the LOS guidance.However,the existing VF guidance is only available for straight lines and orbits rather than curved paths,a considerable obstacle that limits its practical application(see[8],[9]).Thus,the VF guidance for curved path following deserves more in-depth study.
基金supported by the National Natural Science Foundation of China, No.82274616the Key Laboratory Project for General Universities in Guangdong Province, No.2019KSYS005Guangdong Province Science and Technology Plan International Cooperation Project, No.2020A0505100052 (all to QW)。
文摘Meningeal lymphatic vessels form a relationship between the nervous system and periphery, which is relevant in both health and disease. Meningeal lymphatic vessels not only play a key role in the drainage of brain metabolites but also contribute to antigen delivery and immune cell activation. The advent of novel genomic technologies has enabled rapid progress in the characterization of myeloid and lymphoid cells and their interactions with meningeal lymphatic vessels within the central nervous system. In this review, we provide an overview of the multifaceted roles of meningeal lymphatic vessels within the context of the central nervous system immune network, highlighting recent discoveries on the immunological niche provided by meningeal lymphatic vessels. Furthermore, we delve into the mechanisms of crosstalk between meningeal lymphatic vessels and immune cells in the central nervous system under both homeostatic conditions and neurodegenerative diseases, discussing how these interactions shape the pathological outcomes. Regulation of meningeal lymphatic vessel function and structure can influence lymphatic drainage, cerebrospinal fluid-borne immune modulators, and immune cell populations in aging and neurodegenerative disorders, thereby playing a key role in shaping meningeal and brain parenchyma immunity.
基金the National Natural Science Foundation of China(No.82374295)the National Key R&D Program of China(No.2021YFE0111100)+1 种基金the Science and Technol-ogy Partnership Program by the Ministry of Science and Technol-ogy of China(No.KY202201002)the Jiangsu Provincial De-partment of Science and Technology(No.BZ2022017).
文摘Cardiovascular disease(CVD)is a major global health challenge,which causes significant illness and death worldwide.These include a range of conditions that affect the heart and blood vessels,including coro-nary artery disease,stroke,peripheral artery disease,and heart failure.Despite advances in medicine and healthcare delivery,CVD continues to have a serious impact on individuals,families,and the healthcare system.This review begins by delineating the merits and demerits of commonly employed synthetic and natural materials for artificial blood vessels.It delves into various techniques commonly employed in the fabrication of artificial blood vessels,encompassing advanced textile technologies,electrospinning,ther-mally induced phase separation,and 3D printing.The review critically analyzes the attributes of different preparation methodologies alongside the latest advancements in research.The review also outlines the requisite performance requirements for artificial blood vessels,which encompass robust mechanical prop-erties,appropriate porosity,exceptional compatibility,and antibacterial attributes.It provides a succinct overview of ongoing effort s in vascular functionalization,particularly emphasizing thrombus mitigation,promotion of endothelialization,and enhancement of nitric oxide production.The review finally encap-sulates the primary challenges confronting vascular grafts and prospective avenues for future research.
文摘Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited training data,imbalance data distribution,and inadequate feature extraction persist,hindering both the segmentation performance and optimal model generalization.Addressing these critical issues,the DEFFA-Unet is proposed featuring an additional encoder to process domain-invariant pre-processed inputs,thereby improving both richer feature encoding and enhanced model generalization.A feature filtering fusion module is developed to ensure the precise feature filtering and robust hybrid feature fusion.In response to the task-specific need for higher precision where false positives are very costly,traditional skip connections are replaced with the attention-guided feature reconstructing fusion module.Additionally,innovative data augmentation and balancing methods are proposed to counter data scarcity and distribution imbalance,further boosting the robustness and generalization of the model.With a comprehensive suite of evaluation metrics,extensive validations on four benchmark datasets(DRIVE,CHASEDB1,STARE,and HRF)and an SLO dataset(IOSTAR),demonstrate the proposed method’s superiority over both baseline and state-of-the-art models.Particularly the proposed method significantly outperforms the compared methods in cross-validation model generalization.
基金Supported by Shenzhen Municipal Scientific and Technological Innovation Committee:JCYJ 20140408152909270Project of Shenzhen Municipal Key Laboratory of Technical Research and Development Fund Conditions and Platform Construction Plan:CXB 201111250113A
文摘Objective To explore the effect of electroacupuncture at conception vessel and governor vessel on correlative signals of inflammatory response stressinjury-repair in cerebral ischemia reperfusion rats. Methods A total of 216 rats were included in the experiment, of which 192 rats were randomly divided into four groups, including sham operation group（group A）, model group（group B）, governor vessel group（group C）, and conception vessel and governor vessel group（group D）, 48 rats in each group. The rats in each group were further divided into six sub-groups, including 12 h group, 24 h group, 48 h group, 72 h group, 96 h group and 144 h group. MCAO operation course was simulated in group A, and the common carotid artery, internal carotid artery and external carotid artery on the right side were exposed, without insertion of suture or treatment. After completion of modeling in group B, treatment was not conducted. After completion of modeling in group C, ＂Shuǐgōu（水沟 GV 26）＂, ＂Bǎihuì（百会 GV 20）＂ and ＂Dàzhuī（大椎 GV 14）＂ of governor vessel were selected, and electroacupuncture device was connected with ＂GV 14＂ and ＂GV 20＂. After completion of modeling in group D, ＂GV 26＂, ＂GV 20＂ and ＂GV 14＂ of governor vessel, and ＂Qìhǎi（气海 CV 6）＂, ＂Guānyuán（关元 CV 4）＂ and ＂Chéngjiāng（承浆 CV 24）＂ of conception vessel were selected; electroacupuncture device was connected with ＂GV 14＂ and ＂GV 20＂, ＂CV 4＂ and ＂CV 6＂. Neurological severity score was conducted.Enzyme linked immunosorbent assay（ELISA） was applied to determine the concentration of peripheral serum adrenocorticotropic hormone（ACTH） of rats, and immunohistochemical method was adopted to detect the expression levels of tumor necrosis factor α（TNF-α） and transforming growth factor β1（TGF-β1） in brain tissue of rats. The other 24 rats were also randomly divided into four groups mentioned above, 6 rats in each group, to detect cerebral ischemie volume. Results Compared with group B, the ischemia volume in brain tissue at 144 h after cerebral ischemia reperfusion decreased significantly in group C and group D（P〈0.05）, and the ischemia volume in group D was less than that in group C（P〈0.05）. The neurological impairment scores of group C and group D at all time points were lower than those of group B, and the differences were statistically significant（all P〈0.05）. The scores of group D at all time points were lower than those of group C, and the differences since 24 h were statistically significant（all P〈0.05）. Compared with group B, the excessive expression of ACTH was suppressed dynamically and generally in group C and group D（P〈0.05）; the expression level of TNF-α was down-regulated and TGF-β1 was up-regulated as well in group C and group D（P〈0.05）. The effect in group D was superior to that in group C. Conclusion Electroacupuncture at conception vessel and governor vessel can protect brain through the intervention of the expression of correlative signals of inflammatory response stress-injury-repair of cerebral ischemia reperfusion.
基金supported by Shenzhen 2022 Key Project for Technological Research(Grant Number JSGG20220831110803006)key technology research and demonstration project of 10 MW deep-sea floating offshore wind turbine(DTGD-2023-10174)key technology research task of floating offshore combined wind and wave power generation and MIIT program for Floating VAWT.
文摘As a vessel navigates at high speeds in waves,considerable pitching motion can result in the discomfort of passengers.In this study is proposed a ride control system consisting of dual T-foils to generate a larger righting moment than a common single T-foil system.One T-foil is mounted at the bow,and the other at the stern.Accordingly,different control strategies for dual T-foils were proposed To verify the stratigies,a model experiment was conducted in the Towing Tank,Dalian Unievrsity of Technology.The optimal control signal was determined by comparing the pitch responses,heave responses,bow accelerations,and stern accelerations of a vessel in regular waves.In addition,the control strategy for the best motion-reduction effect was investigated.The optimized dual T-foil system provides a 34%reduction in pitch motion.
文摘As global efforts to combat climate change intensify,offshore wind farms have emerged as scalable and sustainable solutions.However,their deployment depends heavily on the availability of specialized vessels with Dynamic Positioning(DP)systems such as Wind Turbine Installation Vessels(WTIVs)and Service Operation Vessels(SOVs).Despite their importance,long-term demand forecasting for such vessels remains underexplored,especially in South Korea.This study presents the dDP-W model,a System Dynamics(SD)-based framework that simulates the evolving demand for DP vessels under varying technological,policy,and environmental conditions.Unlike conventional methods based on historical extrapolation,the model uses feedback-driven causality and scenario-based simulations aligned with South Korea’s offshore wind roadmap(2026-2036).Three WTIV demand scenarios—baseline,optimistic,and pessimistic—were constructed based on vessel productivity and weather-related downtime.SOV demand was estimated using cumulative turbine counts and fixed vessel coverage ratios.The simulations indicate that WTIV demand peaks in the early 2030s,requiring 6 to 7 vessels depending on conditions,while SOV demand increases steadily,reaching nearly 70 vessels by 2036.These findings highlight the need for early vessel procurement,infrastructure investment,and workforce preparation.By integrating technical,logistical,and policy factors into a dynamic model,this study provides a practical decision-support tool for stakeholders in shipbuilding and offshore energy.The results offer strategic insights to address potential vessel shortages and ensure alignment with national renewable energy goals.
基金Supported by Wu Jieping Medical Foundation(No.320.6750.2021-4-15).
文摘AIM:To compare the effects of different types of negative pressure suction on the macular and optic disc retinal vessel density(VD)in myopic patients with different axial lengths(ALs)undergoing femtosecond laser-assisted excimer laser in situ keratomileusis(FS-LASIK)by optical coherence tomography angiography(OCTA).METHODS:A prospective,nonrandomized,controlled study.Participants underwent FS-LASIK surgery were divided into the short AL group(SAL,22≤AL<26 mm)and the long AL group(LAL,26≤AL<28 mm)according to the different ALs.Further,the two groups were divided into subgroups according to the corneal flap using VisuMax or WaveLight FS200 femtosecond laser(FS)platform.All patients underwent OCTA before the surgery and 1-day/1-week/1-month after the surgery.ANOVA statistically analyzed data with two-factor repeated measurement in SPSS.RESULTS:Totally 108 participants(108 eyes,18–35y)were divided into SAL group[22 patients(4 males and 18 females)were treated with VisuMax,and 24(3 males and 21 females)were treated with WaveLight FS200]and LAL group[34 patients(4 males and 30 females)were treated with VisuMax,and 28 patients(6 males and 22 females)were treated with WaveLight FS200].In the LAL group,there was no significant difference in macular superficial capillary plexuses vessel density(SCP-VD)in the fovea and perifovea region,but compared with the VisuMax subgroup,SCP-VD in the parafoveal region(t=2.647,P=0.010)and the whole area(t=2.030,P=0.047)in WaveLight FS200 subgroup decreased at one day after the operation and increased to a preoperative level at 1-week and 1-month after operation.There was no significant difference between SCP-VD in the two SAL subgroups,neither of deep capillary plexuses vessel density(DCP-VD)and optic nerve head vessel density(ONH-VD)in the SAL and LAL groups.CONCLUSION:With the increase of AL and suction intensity,a transient decrease of SCP-VD in the macular region is observed at 1d postoperatively during FS-LASIK,and it increases to preoperative level at 1-week and 1-month postoperatively.However,the AL and suction intensity do not affect the macular DCP-VD and ONH-VD.
基金The 2019 Guangdong Province General College Youth Innovation Talent Project(2019GKQNCX009)。
文摘Since the problems of branch loss and fracture in retinal blood vessel segmentation algorithms,an image segmentation method is proposed based on improved pulse coupled neural network(PCNN)and gray wolf optimization algorithm(GWO).Simplifying the neuron input domain and neuron connection domain of the PCNN network,increasing the gradient information factor in the internal activity items,reducing the model parameters,enhancing the pulse issuing ability,and the optimal parameters of the network are automatically obtained based on multiple feature evaluation criteria and the GWO algorithm.The test in the public data set drive shows that the sensitivity,accuracy,precision,and specificity of the algorithm are 0.799549,0.962789,0.889163,and 0.986552,respectively.The accuracy and specificity are better than the classical segmentation algorithm.It solved the influence of low illumination,optic disc highlight,and foveal shadow on vascular segmentation,and showed excellent performance of vessel connectivity and terminal sensitivity.
基金supported by the National Key research and Development Program of China(No.2022YFB4003001).
文摘The mechanical properties,microstructure and second phase precipitation behavior of flange forgings for high-pressure hydrogen storage vessels at different tempering temperatures(620–700℃)were studied.The results showed that when tempered at 620–680°C,the main microstructure of the test steel was tempered sorbite,and the main microstructure of tempered steel changed to martensite at 700℃.At 700℃,the dislocation density increased and some retained austenite existed.With the tempering temperature increasing,the yield strength showed a decreasing trend,the formation of fresh martensite made the tensile strength first decrease and then increase slightly,the impact energy at−40℃increased first and then decreased,and the impact energy at 660℃had the maximum value.The precipitates of MC type were mainly(Mo,V,Ti)C.The test steel had excellent strength and toughness matching at 660℃tempering,the tensile strength at different cross section locations was above 750 MPa,the impact energy was above 200 J at−40℃,and the relative percentage reduction of area(ZH2/ZN2)was above 75%at hydrogen environment of 6.3 MPa.
文摘Objective:To study the application effect of bundle nursing strategy in the maintenance of difficult blood vessels for long-term hemodialysis patients.Methods:A prospective study was conducted on 40 long-term hemodialysis patients admitted from January 2024 to January 2025.The patients were randomly divided into a control group(20 cases)and an observation group(20 cases)using computer random sampling.The control group received routine nursing for difficult blood vessels,while the observation group received a bundle nursing strategy for difficult blood vessels.The self-care ability,complication rate,and nursing satisfaction were compared between the two groups.Results:After nursing,the self-care ability score of the observation group was higher than that of the control group(P<0.05).The complication rate in the observation group was lower than that in the control group(P<0.05).The nursing satisfaction in the observation group was higher than that in the control group(P<0.05).Conclusion:The application of the bundle nursing strategy in the maintenance of difficult blood vessels for long-term hemodialysis patients is beneficial for improving self-care ability,reducing complications,and increasing patient satisfaction with nursing services.
基金supported by Natural Science Research Project of Tianjin Education Commission(Grant 2020KJ124)National Natural Science Foundation of China(Grant 11601372)National Key Research and Development Program of China(Grant 2022YFF0706003).
文摘The segmentation of retinal vessels and coronary angiographs is essential for diagnosing conditions such as glaucoma,diabetes,hypertension,and coronary artery disease.However,retinal vessels and coronary angiographs are characterized by low contrast and complex structures,posing challenges for vessel segmentation.Moreover,CNN-based approaches are limited in capturing long-range pixel relationships due to their focus on local feature extraction,while ViT-based approaches struggle to capture fine local details,impacting tasks like vessel segmentation that require precise boundary detection.To address these issues,in this paper,we propose a Global–Local Hybrid Modulation Network(GLHM-Net),a dual-encoder architecture that combines the strengths of CNNs and ViTs for vessel segmentation.First,the Hybrid Non-Local Transformer Block(HNLTB)is proposed to efficiently consolidate long-range spatial dependencies into a compact feature representation,providing a global perspective while significantly reducing computational overhead.Second,the Collaborative Attention Fusion Block(CAFB)is proposed to more effectively integrate local and global vessel features at the same hierarchical level during the encoding phase.Finally,the proposed Feature Cross-Modulation Block(FCMB)better complements the local and global features in the decoding stage,effectively enhancing feature learning and minimizing information loss.The experiments conducted on the DRIVE,CHASEDB1,DCA1,and XCAD datasets,achieving AUC values of 0.9811,0.9864,0.9915,and 0.9919,F1 scores of 0.8288,0.8202,0.8040,and 0.8150,and IOU values of 0.7076,0.6952,0.6723,and 0.6878,respectively,demonstrate the strong performance of our proposed network for vessel segmentation.
基金financially supported by the National Natural Science Foundation of China(No.52171042),the National Key Research and Development Program of China(No.2023YFB3406804)the“Jianbing”R&D Program of Zhejiang Province,China(No.2023C01081)the Na-tional Engineering Research Center for Advanced Manufac-turing Technology and Equipment of Heavy Castings and Forgings(Erzhong(Deyang)Heavy Equipment Co.,Ltd.).
文摘Tensile deformation and microvoid formation of quenched and tempered SA508 Gr.3 steel were studied using an in-situ digital image correlation technique and in-situ electron backscatter diffraction(EBSD)measurements.The quenched steel with a mixture of up-per bainite and granular bainite exhibited a high ultimate tensile strength(UTS)of~795 MPa and an elongation of~25%.After temper-ing,long-rod carbides and accumulated carbide particles were formed at the interface of bainite–ferrite subunits and prior austenite grain boundaries(PAGBs),respectively.The UTS of the tempered steel decreased to~607 MPa,whereas the total elongation increased to 33.0%with a local strain of 191.0%at the necked area.In-situ EBSD results showed that strain localization in the bainite–ferrite pro-duced lattice rotation and dislocation pileup,thus leading to stress concentration at the discontinuities(e.g.,martensite–austenite islands and carbides).Consequently,the decohesion of PAGBs dotted with martensite–austenite islands was the dominant microvoid initiation mechanism in the quenched steel,whereas microvoids primarily initiated through the fracturing of long-rod carbides and the decohesion of PAGBs with carbides aggregation in the tempered steel.The fracture surfaces for both the quenched and tempered specimens featured dimples,indicating the ductile failure mechanism caused by microvoid coalescence.
文摘To address low detection accuracy in near-coastal vessel target detection under complex conditions,a novel near-coastal vessel detection model based on an improved YOLOv7 architecture is proposed in this paper.The attention mechanism Coordinate Attention is used to improve channel attention weight and enhance a network’s ability to extract small target features.In the enhanced feature extraction network,the lightweight convolution algorithm Grouped Spatial Convolution is used to replace MPConv to reduce model calculation costs.EIoU Loss is used to replace the regression frame loss function in YOLOv7 to reduce the probability of missed and false detection.The performance of the improved model was verified using an enhanced dataset obtained through rainy and foggy weather simulation.Experiments were conducted on the datasets before and after the enhancement.The improved model achieved a mean average precision(mAP)of 97.45%on the original dataset,and the number of parameters was reduced by 2%.On the enhanced dataset,the mAP of the improved model reached 88.08%.Compared with seven target detection models,such as Faster R-CNN,YOLOv3,YOLOv4,YOLOv5,YOLOv7,YOLOv8-n,and YOLOv8-s,the improved model can effectively reduce the missed and false detection rates and improve target detection accuracy.The improved model not only accurately detects vessels in complex weather environments but also outperforms other methods on original and enhanced SeaShip datasets.This finding shows that the improved model can achieve near-coastal vessel target detection in multiple environments,laying the foundation for vessel path planning and automatic obstacle avoidance.
