This paper presents a new algorithm for line clipping against a polygonal window by exploiting the local relationship between each line segment and the polygon. Firstly, a minimal enclosing box （MEB） of the polygon ...This paper presents a new algorithm for line clipping against a polygonal window by exploiting the local relationship between each line segment and the polygon. Firstly, a minimal enclosing box （MEB） of the polygon is adopted to reject the invisible line segments located outside the MEB. Secondly, a 45° rotated box is used to encode the endpoint of the line segment, and then reject a portion of the invisible segments crossing polygon comers. Finally, instead of encoding the endpoints of all line segments with respect to the polygonal window, each vertex of the polygon is encoded, taking the line segment to be clipped as reference. For efficient encoding of the polygon vertices, a new concept, termed with slope adaptive virtual box, is introduced regarding each line segment. Such a box can not only conveniently reject all totally invisible lines lying outside the MEB conveniently, but also precisely identify the edges of the polygon with which the line segment potentially intersects. With the summation of the vertex codes, it can be verified whether the line segment is separated from or potentially intersects the polygon window. Based on the product of the codes of adjacent vertices, singular cases of intersection can be solved accurately. Experimental results demonstrate the efficiency and stability of the new algorithm.展开更多
This paper addresses a critical challenge in the design of MEMS actuators:the rejection of out-of-plane motion,specifically along the Z-axis,which can severely impact the precision and performance of these micro-actua...This paper addresses a critical challenge in the design of MEMS actuators:the rejection of out-of-plane motion,specifically along the Z-axis,which can severely impact the precision and performance of these micro-actuation systems.In many MEMS applications,unwanted out-of-plane displacement can lead to reduced accuracy in tasks such as optical steering,micro-manipulation,and scanning applications.In response to these limitations,this paper proposes a novel design technique that effectively rejects Z-axis motion by transforming the motion of the micro stage along the Z-axis into equivalent displacements between pairs of points on cantilevers.These point pairs are founded exhibiting variable common-mode and differential-mode motion characteristics,depending on whether the stage is undergoing in-plane(X/Y)or out-of-plane(Z)displacements.By connecting these point pairs with rods,differential motion between the points in the pairs is suppressed,reducing unwanted out-of-plane motion significantly.We provide a detailed analysis of this design methodology and present a practical application in the form of an electromagnetic large displacement MEMS actuator.This actuator undergoes a complete design-simulationmanufacturing-testing cycle,where the effectiveness of the Z-axis motion rejection structure is systematically evaluated,and compared against traditional designs.Experimental results reveal a significant improvement in performance,with static and dynamic travel ranges reaching±60μm and±400μm,respectively.Moreover,the Z-axis stiffness was enhanced by 68.5%,which is more than five times the improvement observed in the X/Y axes’stiffness.These results highlight the potential of the proposed method to provide a robust solution for out-of-plane motion suppression in MEMS actuators,offering improved performance without compromising other critical parameters such as displacement and actuation speed.展开更多
Over the past six decades,liver transplantation(LT)has evolved from an experimental procedure into a standardized and life-saving intervention,reshaping the landscape of organ transplantation.Driven by pioneering brea...Over the past six decades,liver transplantation(LT)has evolved from an experimental procedure into a standardized and life-saving intervention,reshaping the landscape of organ transplantation.Driven by pioneering breakthroughs,technological advancements,and a deepened understanding of immunology,LT has seen remarkable progress.Some of the most notable breakthroughs in the field include advances in immunosuppression,a revised model for end-stage liver disease,and artificial intelligence(AI)-integrated imaging modalities serving diagnostic and therapeutic roles in LT,paired with ever-evolving technological advances.Additionally,the refinement of transplantation procedures,resulting in the introduction of alternative transplantation methods,such as living donor LT,split LT,and the use of marginal grafts,has addressed the challenge of organ shortage.Moreover,precision medicine,guiding personalized immunosuppressive strategies,has significantly improved patient and graft survival rates while addressing emergent issues,such as short-term complications and early allograft dysfunction,leading to a more refined strategy and enhanced postoperative recovery.Looking ahead,ongoing research explores regenerative medicine,diagnostic tools,and AI to optimize organ allocation and posttransplantation car.In summary,the past six decades have marked a transformative journey in LT with a commitment to advancing science,medicine,and patient-centered care,offering hope and extending life to individuals worldwide.展开更多
Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical...Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical arms.The performance of the servo drive,which encompasses the response to the torque,efficiency,control bandwidth and the steady-state positioning accuracy,significantly influences the performance of the aviation actuation.Consequently,enhancing the control bandwidth and refining the positioning accuracy of aviation electro-mechanical actuation servo drives have emerged as a focal point of research.This paper investigates the multi-source disturbances present in aviation electro-mechanical actuation servo systems and summarizes recent research on high-performance servo control methods based on active disturbance rejection control(ADRC).We present a comprehensive overview of the research status pertaining to servo control architecture,strategies for suppressing disturbances in the current loop,and ADRC-based strategies for the position loop.We delineate the research challenges and difficulties encountered by aviation electro-mechanical actuation servo drive control technology.展开更多
Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripher...Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.展开更多
In this article,we comment on an article published in a recent issue of the World Journal of Gastroenterology.We specifically focus on the roles of human leukocyte antigen(HLA)and donor-specific antibodies(DSAs)in ped...In this article,we comment on an article published in a recent issue of the World Journal of Gastroenterology.We specifically focus on the roles of human leukocyte antigen(HLA)and donor-specific antibodies(DSAs)in pediatric liver transpl-antation(LT),as well as the relationship between immune rejection after LT and DSA.Currently,LT remains the standard of care for pediatric patients with end-stage liver disease or severe acute liver failure.However,acute and chronic re-jection continues to be a significant cause of graft dysfunction and loss.HLA mismatch significantly reduces graft survival and increases the risk of acute rejection.Among them,D→R one-way mismatch at three loci was significantly related to graft-versus-host disease incidence after LT.The adverse impact of HLA-DSAs on LT recipients is already established.Therefore,the evaluation of HLA and DSA is crucial in pediatric LT.展开更多
The role of antibodies in kidney transplant(KT)has evolved significantly over the past few decades.This role of antibodies in KT is multifaceted,encompassing both the challenges they pose in terms of antibody-mediated...The role of antibodies in kidney transplant(KT)has evolved significantly over the past few decades.This role of antibodies in KT is multifaceted,encompassing both the challenges they pose in terms of antibody-mediated rejection(AMR)and the opportunities for improving transplant outcomes through better detection,prevention,and treatment strategies.As our understanding of the immunological mechanisms continues to evolve,so too will the approaches to managing and harnessing the power of antibodies in KT,ultimately leading to improved patient and graft survival.This narrative review explores the multifaceted roles of antibodies in KT,including their involvement in rejection mechanisms,advancements in desensitization protocols,AMR treatments,and their potential role in monitoring and improving graft survival.展开更多
In recent years, the use of new biomarkers in different phases of the diagnosis andtreatment of several diseases has allowed substantial improvement in clinicalpractice. The use of donor-derived cell-free DNA (dd-cfDN...In recent years, the use of new biomarkers in different phases of the diagnosis andtreatment of several diseases has allowed substantial improvement in clinicalpractice. The use of donor-derived cell-free DNA (dd-cfDNA) in organ transplantationhas led to significant progress in the treatment of post-transplantoutcomes, particularly after kidney transplantation. In addition, the use of ddcfDNAin organ transplantation has led to significant advancements in posttransplantoutcome monitoring. The aim of this study is to review many of therecent studies on the use of this biomarker and to evaluate its most relevantadvantages and limitations. dd-cfDNA is released from several types of cells ofthe transplanted organ, most often from endothelial cells and this happens in thecase of organ damage, most often rejection. Its presence in the bloodstream of therecipients is an important sign of graft damage;its principal advantage is in theavoidance of invasive tools such as renal biopsy. Additionally, several studiesreported that the finding of dd-cfDNA in the serum may precede histologicalabnormalities;its utility in the diagnosis of subclinical rejection is extremelyimportant. Among the principal limitations of this tool are the difficulty in distinguishingdifferent forms of graft damage. According to several studies this toolhas several limitations in diagnosing T-cell mediated rejection. In addition,particular care should be taken in distinguishing dd-cfDNA from recipientderivedcfDNA.展开更多
1 Active Disturbance Rejection Control(ADRC):a brief survey Since its inception,Active Disturbance Rejection Control(ADRC)has re-centered feedback controller design around two fundamental ideas—along with a consequen...1 Active Disturbance Rejection Control(ADRC):a brief survey Since its inception,Active Disturbance Rejection Control(ADRC)has re-centered feedback controller design around two fundamental ideas—along with a consequential design simplification:real-time estimation and online cancellation of the“total disturbance”conceived as the lumped effect of unknown internal dynamics and external inputs.The simplified design then proceeds in a customary fashion for the ideally remaining system model,which is devoid of the total disturbance.展开更多
Antibody-mediated rejection(AMR)represents a major challenge in kidney transplantation,significantly contributing to tissue injury and graft failure.AMR is primarily driven by donor-specific alloantibodies(DSAs),which...Antibody-mediated rejection(AMR)represents a major challenge in kidney transplantation,significantly contributing to tissue injury and graft failure.AMR is primarily driven by donor-specific alloantibodies(DSAs),which recognize and bind to specific target antigens present within the transplanted kidney tissue.Upon binding,these DSAs commonly initiate activation of the complement system within the graft.The activation of the complement cascade sets off a powerful inflammatory response characterized by the recruitment and activation of immune cells,endothelial damage,and subsequent tissue injury.This inflammation underlies many clinical and histological manifestations of AMR,making complement activation a critical player in the disease process.Advancements in our understanding of how complement pathways contribute to kidney graft injury have opened new avenues for therapeutic intervention.Recent research has facilitated the development and application of novel therapies specifically designed to inhibit complement activation.Such targeted complement-inhibitory strategies have shown promise in improving graft outcomes by inhibiting complement-mediated damage and extending graft survival.This review comprehensively discusses the critical role of complement activation in inducing kidney graft injury with a focus on its role in AMR.By elucidating the detailed mechanisms and contributions of complement pathways,the review seeks to enhance the understanding necessary for developing targeted therapeutic interventions to prevent or treat AMR effectively.展开更多
BACKGROUND The Luminex platform,where beads are coated with single human leukocyte antigens(HLA),detects HLA antibodies with higher sensitivity and specificity compared to complement-dependent cytotoxicity(CDC)assay a...BACKGROUND The Luminex platform,where beads are coated with single human leukocyte antigens(HLA),detects HLA antibodies with higher sensitivity and specificity compared to complement-dependent cytotoxicity(CDC)assay and flow crossmatch(FCXM).The clinical significance of donor-specific antibodies(DSAs)detected by this method is still under investigation.AIM To report the impact of low-level pretransplant DSAs detected by the Luminex platform on the rates of acute rejection(AR),allograft function,and long-term graft survival.METHODS This retrospective study was conducted at the Immunology Department of Sindh Institute of Urology and Transplantation,Karachi,Pakistan between January 2013 and December 2022.During this period 2714 patients were transplanted.Out of these patients 78(2.9%)patients had low-level DSAs detected by the Luminex flow beads method and were negative by CDC and FCXM with their donors.All recipients received ABO-compatible live-related kidney transplants.All patients had a minimum follow-up of 1 year.Graft rejection rates,graft function,and patient and graft survival were analyzed.The estimated glomerular filtration rate was calculated by the full CKD-EPI formula.RESULTS The mean age of all recipients was 29.57±10.11 years and 34.53±9.09 years for the donors.In 48(61.5%)patients,the cause of end-stage kidney disease was unknown.DSA against HLA class I was detected in 36(46.1%)patients,class II in 35(44.8%)patients,and both class I and II in 7(8.9%)patients.AR episodes were encountered in 8(10.3%)cases.Seven(87.5%)had T cell mediated rejection(type IA)and one acute antibody-mediated rejection.Antibody status was re-evaluated at the time of biopsy-proven ARs.Five(62.5%)patients lost their DSAs,while three(37.5%)had persistent DSAs.The mean estimated glomerular filtration rate at 1 year was 80.56±27.48 mL/min/1.73 m2 and at the last follow-up 73.41±28.80 mL/min/1.73 m2.The 1-year and 10-year patient and graft survival rates were 99%and 79%and 95%and 75%,respectively.During the follow-up period,10(12.8%)patients died,8 patients had a functioning graft,and 2 patients had failed grafts.Eight patients died due to cardiopulmonary arrest,and two died due to sepsis with failed grafts.CONCLUSION Patients with pretransplant low-level DSAs on Luminex without CDC and FCXM reactivity had good allograft outcomes at 1 year and 10 years as long as they are induced with biological agents and given potent maintenance immunosuppressants.展开更多
Antibody-mediated rejection(ABMR)and recurrent primary renal disease(PRD)represent major causes of kidney transplant(KT)loss.The standard of care for desensitization,ABMR,and relapsing autoimmune glomerulopathies or n...Antibody-mediated rejection(ABMR)and recurrent primary renal disease(PRD)represent major causes of kidney transplant(KT)loss.The standard of care for desensitization,ABMR,and relapsing autoimmune glomerulopathies or nephrotic syndrome includes apheresis for antibody removal and polyclonal immunoglobulin for antibody blockage.Although frequently used to achieve B-cell depletion,the administration of the type 1 anti-CD20 monoclonal antibodies(mAb)rituximab(RTX)or ofatumumab(OFA)has failed to demonstrate a significant survival benefit.Obinutuzumab(OBI)is a humanized glycoengineered type 2 anti-CD20 mAb.Compared to RTX or OFA,OBI-induced B-cell depletion is not related to complement-dependent cytotoxicity,mostly operating through antibody-dependent cell-mediated cytotoxicity,antibody-dependent phagocytosis,and direct cell death.These characteristics could play a pivotal role in the development of new anti-rejection strategies,enabling the simultaneous administration of complement inhibitors and B-cell-depleting agents.OBI has also demonstrated more powerful peripheral and central B-cell depletion capacities than RTX,with enhanced effects on memory B cells and plasmablasts.In patients with autoimmune glomerulopathies or multidrug-dependent nephrotic syndrome,OBI has shown encouraging results,representing a potential evolution of the treatment of post-transplant relapsing PRD.The present review summarizes the current knowledge on OBI use in KT setting.展开更多
Organ transplantation has long been recognized as an effective treatment for endstage organ failure,metabolic diseases,and malignant tumors.However,graft rejection caused by major histocompatibility complex mismatch r...Organ transplantation has long been recognized as an effective treatment for endstage organ failure,metabolic diseases,and malignant tumors.However,graft rejection caused by major histocompatibility complex mismatch remains a significant challenge.While modern immunosuppressants have made significant strides in reducing the incidence and risk of rejection,they have not been able to eliminate it completely.The intricate mechanisms underlying transplant rejection have been the subject of intense investigation by transplant immunologists.Among these factors,autophagy has emerged as a key player.Autophagy is an evolutionarily conserved mechanism in eukaryotic cells that mediates autophagocytosis and cellular protection.This process is regulated by autophagy-related genes and their encoded protein families,which maintain the material and energetic balance within cells.Additionally,autophagy has been reported to play crucial roles in the development,maturation,differentiation,and responses of immune cells.In the complex immune environment following transplantation,the role and mechanisms of autophagy are gradually being revealed.In this review,we aim to explore the current understanding of the role of autophagy in solid organ rejection after transplantation.Furthermore,we delve into the therapeutic advancements achieved by targeting autophagy involved in the rejection process.展开更多
The study of Mecanum mobile robots typically assumes motion on planar surfaces,while the challenges posed by inclined terrains remain largely unexplored,leaving a significant gap in control applications for such scena...The study of Mecanum mobile robots typically assumes motion on planar surfaces,while the challenges posed by inclined terrains remain largely unexplored,leaving a significant gap in control applications for such scenarios.In this context,two critical issues emerge:the gravitational pull caused by adding a potential energy term in the robot dynamics,which drives the vehicle downhill,and several positioning errors due to vibrations and slippage of the Mecanum wheel.To address these challenges,this work presents an Active Disturbance Rejection Control(ADRC)-based framework designed to enable accurate tracking on inclined surfaces,despite the compounded effects of gravitational forces and slippage.Unlike conventional controllers,the proposed method requires minimal model knowledge while actively compensates for unknown dynamics and external disturbances in real time.A complete theoretical formulation is provided,supported by numerical simulations and comprehensive experimental validation.Results demonstrate that the ADRC structure significantly outperforms not only the traditional proportional-integral-derivative(PID)control but also a robust variant of PID combined with a Quasi-Sliding Mode control(PID-QSMC)strategy,achieving superior tracking.Notably,this study offers an important experimental validation of ADRC for Mecanum-wheeled robots operating on inclined surfaces.It contributes a practical and scalable solution to extend their operational capabilities beyond flat environments.展开更多
BACKGROUNDLiving donor kidney transplantation (LDKT) is considered the gold standard fortreating end-stage kidney disease. Previous studies have highlighted the impact ofdonor and recipient demographics in influencing...BACKGROUNDLiving donor kidney transplantation (LDKT) is considered the gold standard fortreating end-stage kidney disease. Previous studies have highlighted the impact ofdonor and recipient demographics in influencing post-transplant outcomes. Webelieve that patient and graft outcomes in a tertiary university hospital setting willhave no difference between pairs of standard criteria vs pairs of extended criteria(EC) donors and recipients in LDKT.AIMTo investigate the outcomes of allocating EC donation (ECD) kidneys to ECrecipients (ECR) in LDKT and compare them to standard and mixed standard andEC pair counterparts.METHODSWe collected data from adult LDKTs conducted between April 2017 and April2022. Donor-recipient pairs were grouped based on criteria as follows: (1) Group1: Standard criteria donor (SCD) to standard criteria recipient (SCR);(2) Group 2:SCD to ECR;(3) Group 3: ECD to SCR;and (4) Group 4: ECD to ECR.RESULTSA total of 149 living donor transplants were analysed over a 5-year period. Graftsurvival, patient survival, and graft function were similar across all four groups.The incidence of common postoperative complications was as follows: (1) Perioperative bleeding (5.6%);(2) Surgical site infection (6.8%);and (3) Incisional hernia (7.4%). No statistically significantdifferences were found in patient or graft outcomes amongst the four groups. Multivariate analysis showed thatgroup 4 recipients might experience inferior 5-year graft function (β = -11.8, P = 0.037) when compared with group1.CONCLUSIONIn LDKT, long-term patient and graft outcomes are comparable amongst different combinations of standard vs ECdonors and recipients. These findings show the primary potential of living donor ECD to ECR kidney transplantationwith satisfying outcomes.展开更多
BACKGROUND Heart transplantation is the last and best option for end-stage heart failure management.Early mortality rates have significantly decreased,enabling patients to survive longer with fewer complications,a tre...BACKGROUND Heart transplantation is the last and best option for end-stage heart failure management.Early mortality rates have significantly decreased,enabling patients to survive longer with fewer complications,a trend observed even in our setting.The primary shared challenge has centered on achieving surgical success and immediate survival.The question arises about the medium-and long-term survival of patients with heart transplant in Mexico.AIM To present the results of the medium and long-term follow-up of heart transplant patients.METHODS This was a retrospective study of a single medical unit,and we selected patients who received heart transplants from July 21,1988 to September 30,2023.Selection criteria encompassed age,sex,and primary indication for heart transplantation across all groups.Patients with incomplete information or who died within 30 postoperative days were excluded.Data of primary pathology,ischemic,extracorporeal circulation,aortic cross-clamping times,length of ventilatory support,stay in postoperative therapy,hospitalization,and functional class were analyzed.RESULTS The causes of morbidity,mortality,and percentage of survival at 1,5,and 10 years were examined.Overall,257 heart transplants were performed during the study period.Of the total cases,22 with incomplete data and 47 who died within 30 postoperative days were excluded for the middle-and long-term survival analyses.Of the remaining 188 patients,heart transplantation was performed(males:146,females:42).The average age of the participants was 44.43±14.48 years.The primary indications included ischemic cardiomyopathy(42.55%)and dilated cardiomyopathy(39.36%).The mean durations of mechanical ventilator support,intensive care stay,and hospital stay were 57.55±103.50 hours,9.96±8.59 days,and 19.49±18.23 days,respectively.One-,five-,and ten-year survival rates were 90.7%,71.3%,and 60.3%,respectively.Of the patients,94%and 6%were in functional classes I and II,respectively.Infection and neurological hemorrhagic or ischemic stroke(26%)were the main causes of mortality in the first year.Subsequently,chronic rejection manifesting as graft vasculopathy increased in frequency(30%).CONCLUSION In our setting,heart transplantation yields medium-and long-term survival and quality of life outcomes comparable to those achieved by other international centers.展开更多
The main scientific payload of Macao Science Satellite-1B is a solar soft X-ray detection unit.To obtain an accurate solar X-ray spectrum,we have designed low-noise,high-throughput electronics.Solar radiation is detec...The main scientific payload of Macao Science Satellite-1B is a solar soft X-ray detection unit.To obtain an accurate solar X-ray spectrum,we have designed low-noise,high-throughput electronics.Solar radiation is detected using a low-leakage silicon drift detector(SDD),which is cooled to-30℃.The SDD output is processed using two parallel shaping amplifiers with peaking times of 315 ns and 65 ns.The amplifiers are designed using two-pole multiple-feedback active low-pass filters optimized to achieve a Bessel response.The differential output of the shaping amplifier generates a bipolar signal.The phase of the differential stage is tuned to ensure zero crossing corresponding to the peak of the shaping amplifier.A high-speed switch is inserted between the shaping amplifier and the peak-hold capacitor,and the peak value is maintained by turning off the switch.Fast and slow peak-hold circuits share a common ADC via time-division multiplexing.Both peak values are sampled for space-background rejection.Traditional pile-up detection methods cannot distinguish pulses that overlap in a fast channel.In this study,the differential of the“fast shaping”is selected,enabling the distinction of events separated by as little as 65ns,which is crucial for solar flare detection.The energy resolution is measured to be 138 eV at 5.90 keV.The centroid drift is less than 3.6 eV between-5℃ and 20℃.Compared with other solar X-ray instruments,this study demonstrates improved energy resolution with a lower peaking time,indicating a higher solar flare detection capability.展开更多
Piezoelectric active vibration control holds paramount importance in space structures.An embedded piezoelectric actuator with a sandwich configuration is proposed,which enhances control accuracy by integrating various...Piezoelectric active vibration control holds paramount importance in space structures.An embedded piezoelectric actuator with a sandwich configuration is proposed,which enhances control accuracy by integrating various components.Firstly,the electromechanical coupling characteristics of the actuator are revealed,and the model is established.Secondly,the equivalent model of a cylindrical cantilever beam is investigated as the object,and the feasibility of the vibration control of the actuator is verified by simulation.Finally,the prototype comprised of two actuators,which respectively use the proposed embedded actuators for producing the vibration and suppressing the vibration,is developed,and the measurement system is constructed.Experimental results demonstrate the excellent control efficiency in two orthogonal directions,achieving a minimum vibration amplitude control of 0.00102 mm and a maximum vibration control of-42.74 d B.The integrated structure offers fast response,lightness,adaptability,and high control efficiency,which is conducive to enhancing the vibration control.展开更多
Asia, a major cradle of human civilizations,boasts three of the four ancient civilizations that developed a rich legacy of art, culture and scientific achievements over thousands of years. Since ancient times.
General information Hepatobiliary&Pancreatic Diseases International is a journal published bimonthly in the English language by the First Afliated Hospital,Zhejiang University School of Medicine,Hangzhou,China.We ...General information Hepatobiliary&Pancreatic Diseases International is a journal published bimonthly in the English language by the First Afliated Hospital,Zhejiang University School of Medicine,Hangzhou,China.We welcome original research articles,review articles,editorials,and others from any part of the world.Manuscripts are reviewed by members of the international editorial board and our expert peer reviewers,then either accepted for publication or rejected by the chief editor.Manuscripts should be submitted via https://mc03.mamuscrlptcen tral.com/hbpdint.展开更多
基金Project supported by the National Natural Science Foundation of China(No. 60021201), and the Research Fund for the Doctoral Program of Higher Education (No. 2002335093), China
文摘This paper presents a new algorithm for line clipping against a polygonal window by exploiting the local relationship between each line segment and the polygon. Firstly, a minimal enclosing box （MEB） of the polygon is adopted to reject the invisible line segments located outside the MEB. Secondly, a 45° rotated box is used to encode the endpoint of the line segment, and then reject a portion of the invisible segments crossing polygon comers. Finally, instead of encoding the endpoints of all line segments with respect to the polygonal window, each vertex of the polygon is encoded, taking the line segment to be clipped as reference. For efficient encoding of the polygon vertices, a new concept, termed with slope adaptive virtual box, is introduced regarding each line segment. Such a box can not only conveniently reject all totally invisible lines lying outside the MEB conveniently, but also precisely identify the edges of the polygon with which the line segment potentially intersects. With the summation of the vertex codes, it can be verified whether the line segment is separated from or potentially intersects the polygon window. Based on the product of the codes of adjacent vertices, singular cases of intersection can be solved accurately. Experimental results demonstrate the efficiency and stability of the new algorithm.
基金the National Natural Science Foundation of China(Grant No.U21A6003&Grant No.U24A6006).
文摘This paper addresses a critical challenge in the design of MEMS actuators:the rejection of out-of-plane motion,specifically along the Z-axis,which can severely impact the precision and performance of these micro-actuation systems.In many MEMS applications,unwanted out-of-plane displacement can lead to reduced accuracy in tasks such as optical steering,micro-manipulation,and scanning applications.In response to these limitations,this paper proposes a novel design technique that effectively rejects Z-axis motion by transforming the motion of the micro stage along the Z-axis into equivalent displacements between pairs of points on cantilevers.These point pairs are founded exhibiting variable common-mode and differential-mode motion characteristics,depending on whether the stage is undergoing in-plane(X/Y)or out-of-plane(Z)displacements.By connecting these point pairs with rods,differential motion between the points in the pairs is suppressed,reducing unwanted out-of-plane motion significantly.We provide a detailed analysis of this design methodology and present a practical application in the form of an electromagnetic large displacement MEMS actuator.This actuator undergoes a complete design-simulationmanufacturing-testing cycle,where the effectiveness of the Z-axis motion rejection structure is systematically evaluated,and compared against traditional designs.Experimental results reveal a significant improvement in performance,with static and dynamic travel ranges reaching±60μm and±400μm,respectively.Moreover,the Z-axis stiffness was enhanced by 68.5%,which is more than five times the improvement observed in the X/Y axes’stiffness.These results highlight the potential of the proposed method to provide a robust solution for out-of-plane motion suppression in MEMS actuators,offering improved performance without compromising other critical parameters such as displacement and actuation speed.
文摘Over the past six decades,liver transplantation(LT)has evolved from an experimental procedure into a standardized and life-saving intervention,reshaping the landscape of organ transplantation.Driven by pioneering breakthroughs,technological advancements,and a deepened understanding of immunology,LT has seen remarkable progress.Some of the most notable breakthroughs in the field include advances in immunosuppression,a revised model for end-stage liver disease,and artificial intelligence(AI)-integrated imaging modalities serving diagnostic and therapeutic roles in LT,paired with ever-evolving technological advances.Additionally,the refinement of transplantation procedures,resulting in the introduction of alternative transplantation methods,such as living donor LT,split LT,and the use of marginal grafts,has addressed the challenge of organ shortage.Moreover,precision medicine,guiding personalized immunosuppressive strategies,has significantly improved patient and graft survival rates while addressing emergent issues,such as short-term complications and early allograft dysfunction,leading to a more refined strategy and enhanced postoperative recovery.Looking ahead,ongoing research explores regenerative medicine,diagnostic tools,and AI to optimize organ allocation and posttransplantation car.In summary,the past six decades have marked a transformative journey in LT with a commitment to advancing science,medicine,and patient-centered care,offering hope and extending life to individuals worldwide.
基金supported by the National Natural Science Foundation of China(Nos.52177059 and 52407064).
文摘Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical arms.The performance of the servo drive,which encompasses the response to the torque,efficiency,control bandwidth and the steady-state positioning accuracy,significantly influences the performance of the aviation actuation.Consequently,enhancing the control bandwidth and refining the positioning accuracy of aviation electro-mechanical actuation servo drives have emerged as a focal point of research.This paper investigates the multi-source disturbances present in aviation electro-mechanical actuation servo systems and summarizes recent research on high-performance servo control methods based on active disturbance rejection control(ADRC).We present a comprehensive overview of the research status pertaining to servo control architecture,strategies for suppressing disturbances in the current loop,and ADRC-based strategies for the position loop.We delineate the research challenges and difficulties encountered by aviation electro-mechanical actuation servo drive control technology.
基金supported by grants from the Lone Star Paralysis Foundation,NIH R01NS081063Department of Defense award W81XWH-19-2-0054 to GDB+2 种基金supported by University of Wyoming Startup funds,Department of Defense grant W81XWH-17-1-0402the University of Wyoming Sensory Biology COBRE under National Institutes of Health(NIH)award number 5P20GM121310-02the National Institute of General Medical Sciences of the NIH under award number P20GM103432 to JSB。
文摘Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.
文摘In this article,we comment on an article published in a recent issue of the World Journal of Gastroenterology.We specifically focus on the roles of human leukocyte antigen(HLA)and donor-specific antibodies(DSAs)in pediatric liver transpl-antation(LT),as well as the relationship between immune rejection after LT and DSA.Currently,LT remains the standard of care for pediatric patients with end-stage liver disease or severe acute liver failure.However,acute and chronic re-jection continues to be a significant cause of graft dysfunction and loss.HLA mismatch significantly reduces graft survival and increases the risk of acute rejection.Among them,D→R one-way mismatch at three loci was significantly related to graft-versus-host disease incidence after LT.The adverse impact of HLA-DSAs on LT recipients is already established.Therefore,the evaluation of HLA and DSA is crucial in pediatric LT.
文摘The role of antibodies in kidney transplant(KT)has evolved significantly over the past few decades.This role of antibodies in KT is multifaceted,encompassing both the challenges they pose in terms of antibody-mediated rejection(AMR)and the opportunities for improving transplant outcomes through better detection,prevention,and treatment strategies.As our understanding of the immunological mechanisms continues to evolve,so too will the approaches to managing and harnessing the power of antibodies in KT,ultimately leading to improved patient and graft survival.This narrative review explores the multifaceted roles of antibodies in KT,including their involvement in rejection mechanisms,advancements in desensitization protocols,AMR treatments,and their potential role in monitoring and improving graft survival.
文摘In recent years, the use of new biomarkers in different phases of the diagnosis andtreatment of several diseases has allowed substantial improvement in clinicalpractice. The use of donor-derived cell-free DNA (dd-cfDNA) in organ transplantationhas led to significant progress in the treatment of post-transplantoutcomes, particularly after kidney transplantation. In addition, the use of ddcfDNAin organ transplantation has led to significant advancements in posttransplantoutcome monitoring. The aim of this study is to review many of therecent studies on the use of this biomarker and to evaluate its most relevantadvantages and limitations. dd-cfDNA is released from several types of cells ofthe transplanted organ, most often from endothelial cells and this happens in thecase of organ damage, most often rejection. Its presence in the bloodstream of therecipients is an important sign of graft damage;its principal advantage is in theavoidance of invasive tools such as renal biopsy. Additionally, several studiesreported that the finding of dd-cfDNA in the serum may precede histologicalabnormalities;its utility in the diagnosis of subclinical rejection is extremelyimportant. Among the principal limitations of this tool are the difficulty in distinguishingdifferent forms of graft damage. According to several studies this toolhas several limitations in diagnosing T-cell mediated rejection. In addition,particular care should be taken in distinguishing dd-cfDNA from recipientderivedcfDNA.
文摘1 Active Disturbance Rejection Control(ADRC):a brief survey Since its inception,Active Disturbance Rejection Control(ADRC)has re-centered feedback controller design around two fundamental ideas—along with a consequential design simplification:real-time estimation and online cancellation of the“total disturbance”conceived as the lumped effect of unknown internal dynamics and external inputs.The simplified design then proceeds in a customary fashion for the ideally remaining system model,which is devoid of the total disturbance.
文摘Antibody-mediated rejection(AMR)represents a major challenge in kidney transplantation,significantly contributing to tissue injury and graft failure.AMR is primarily driven by donor-specific alloantibodies(DSAs),which recognize and bind to specific target antigens present within the transplanted kidney tissue.Upon binding,these DSAs commonly initiate activation of the complement system within the graft.The activation of the complement cascade sets off a powerful inflammatory response characterized by the recruitment and activation of immune cells,endothelial damage,and subsequent tissue injury.This inflammation underlies many clinical and histological manifestations of AMR,making complement activation a critical player in the disease process.Advancements in our understanding of how complement pathways contribute to kidney graft injury have opened new avenues for therapeutic intervention.Recent research has facilitated the development and application of novel therapies specifically designed to inhibit complement activation.Such targeted complement-inhibitory strategies have shown promise in improving graft outcomes by inhibiting complement-mediated damage and extending graft survival.This review comprehensively discusses the critical role of complement activation in inducing kidney graft injury with a focus on its role in AMR.By elucidating the detailed mechanisms and contributions of complement pathways,the review seeks to enhance the understanding necessary for developing targeted therapeutic interventions to prevent or treat AMR effectively.
文摘BACKGROUND The Luminex platform,where beads are coated with single human leukocyte antigens(HLA),detects HLA antibodies with higher sensitivity and specificity compared to complement-dependent cytotoxicity(CDC)assay and flow crossmatch(FCXM).The clinical significance of donor-specific antibodies(DSAs)detected by this method is still under investigation.AIM To report the impact of low-level pretransplant DSAs detected by the Luminex platform on the rates of acute rejection(AR),allograft function,and long-term graft survival.METHODS This retrospective study was conducted at the Immunology Department of Sindh Institute of Urology and Transplantation,Karachi,Pakistan between January 2013 and December 2022.During this period 2714 patients were transplanted.Out of these patients 78(2.9%)patients had low-level DSAs detected by the Luminex flow beads method and were negative by CDC and FCXM with their donors.All recipients received ABO-compatible live-related kidney transplants.All patients had a minimum follow-up of 1 year.Graft rejection rates,graft function,and patient and graft survival were analyzed.The estimated glomerular filtration rate was calculated by the full CKD-EPI formula.RESULTS The mean age of all recipients was 29.57±10.11 years and 34.53±9.09 years for the donors.In 48(61.5%)patients,the cause of end-stage kidney disease was unknown.DSA against HLA class I was detected in 36(46.1%)patients,class II in 35(44.8%)patients,and both class I and II in 7(8.9%)patients.AR episodes were encountered in 8(10.3%)cases.Seven(87.5%)had T cell mediated rejection(type IA)and one acute antibody-mediated rejection.Antibody status was re-evaluated at the time of biopsy-proven ARs.Five(62.5%)patients lost their DSAs,while three(37.5%)had persistent DSAs.The mean estimated glomerular filtration rate at 1 year was 80.56±27.48 mL/min/1.73 m2 and at the last follow-up 73.41±28.80 mL/min/1.73 m2.The 1-year and 10-year patient and graft survival rates were 99%and 79%and 95%and 75%,respectively.During the follow-up period,10(12.8%)patients died,8 patients had a functioning graft,and 2 patients had failed grafts.Eight patients died due to cardiopulmonary arrest,and two died due to sepsis with failed grafts.CONCLUSION Patients with pretransplant low-level DSAs on Luminex without CDC and FCXM reactivity had good allograft outcomes at 1 year and 10 years as long as they are induced with biological agents and given potent maintenance immunosuppressants.
文摘Antibody-mediated rejection(ABMR)and recurrent primary renal disease(PRD)represent major causes of kidney transplant(KT)loss.The standard of care for desensitization,ABMR,and relapsing autoimmune glomerulopathies or nephrotic syndrome includes apheresis for antibody removal and polyclonal immunoglobulin for antibody blockage.Although frequently used to achieve B-cell depletion,the administration of the type 1 anti-CD20 monoclonal antibodies(mAb)rituximab(RTX)or ofatumumab(OFA)has failed to demonstrate a significant survival benefit.Obinutuzumab(OBI)is a humanized glycoengineered type 2 anti-CD20 mAb.Compared to RTX or OFA,OBI-induced B-cell depletion is not related to complement-dependent cytotoxicity,mostly operating through antibody-dependent cell-mediated cytotoxicity,antibody-dependent phagocytosis,and direct cell death.These characteristics could play a pivotal role in the development of new anti-rejection strategies,enabling the simultaneous administration of complement inhibitors and B-cell-depleting agents.OBI has also demonstrated more powerful peripheral and central B-cell depletion capacities than RTX,with enhanced effects on memory B cells and plasmablasts.In patients with autoimmune glomerulopathies or multidrug-dependent nephrotic syndrome,OBI has shown encouraging results,representing a potential evolution of the treatment of post-transplant relapsing PRD.The present review summarizes the current knowledge on OBI use in KT setting.
基金Supported by the National Natural Science Foundation of China,No.82100691China Postdoctoral Science Foundation,No.2021M693631.
文摘Organ transplantation has long been recognized as an effective treatment for endstage organ failure,metabolic diseases,and malignant tumors.However,graft rejection caused by major histocompatibility complex mismatch remains a significant challenge.While modern immunosuppressants have made significant strides in reducing the incidence and risk of rejection,they have not been able to eliminate it completely.The intricate mechanisms underlying transplant rejection have been the subject of intense investigation by transplant immunologists.Among these factors,autophagy has emerged as a key player.Autophagy is an evolutionarily conserved mechanism in eukaryotic cells that mediates autophagocytosis and cellular protection.This process is regulated by autophagy-related genes and their encoded protein families,which maintain the material and energetic balance within cells.Additionally,autophagy has been reported to play crucial roles in the development,maturation,differentiation,and responses of immune cells.In the complex immune environment following transplantation,the role and mechanisms of autophagy are gradually being revealed.In this review,we aim to explore the current understanding of the role of autophagy in solid organ rejection after transplantation.Furthermore,we delve into the therapeutic advancements achieved by targeting autophagy involved in the rejection process.
文摘The study of Mecanum mobile robots typically assumes motion on planar surfaces,while the challenges posed by inclined terrains remain largely unexplored,leaving a significant gap in control applications for such scenarios.In this context,two critical issues emerge:the gravitational pull caused by adding a potential energy term in the robot dynamics,which drives the vehicle downhill,and several positioning errors due to vibrations and slippage of the Mecanum wheel.To address these challenges,this work presents an Active Disturbance Rejection Control(ADRC)-based framework designed to enable accurate tracking on inclined surfaces,despite the compounded effects of gravitational forces and slippage.Unlike conventional controllers,the proposed method requires minimal model knowledge while actively compensates for unknown dynamics and external disturbances in real time.A complete theoretical formulation is provided,supported by numerical simulations and comprehensive experimental validation.Results demonstrate that the ADRC structure significantly outperforms not only the traditional proportional-integral-derivative(PID)control but also a robust variant of PID combined with a Quasi-Sliding Mode control(PID-QSMC)strategy,achieving superior tracking.Notably,this study offers an important experimental validation of ADRC for Mecanum-wheeled robots operating on inclined surfaces.It contributes a practical and scalable solution to extend their operational capabilities beyond flat environments.
文摘BACKGROUNDLiving donor kidney transplantation (LDKT) is considered the gold standard fortreating end-stage kidney disease. Previous studies have highlighted the impact ofdonor and recipient demographics in influencing post-transplant outcomes. Webelieve that patient and graft outcomes in a tertiary university hospital setting willhave no difference between pairs of standard criteria vs pairs of extended criteria(EC) donors and recipients in LDKT.AIMTo investigate the outcomes of allocating EC donation (ECD) kidneys to ECrecipients (ECR) in LDKT and compare them to standard and mixed standard andEC pair counterparts.METHODSWe collected data from adult LDKTs conducted between April 2017 and April2022. Donor-recipient pairs were grouped based on criteria as follows: (1) Group1: Standard criteria donor (SCD) to standard criteria recipient (SCR);(2) Group 2:SCD to ECR;(3) Group 3: ECD to SCR;and (4) Group 4: ECD to ECR.RESULTSA total of 149 living donor transplants were analysed over a 5-year period. Graftsurvival, patient survival, and graft function were similar across all four groups.The incidence of common postoperative complications was as follows: (1) Perioperative bleeding (5.6%);(2) Surgical site infection (6.8%);and (3) Incisional hernia (7.4%). No statistically significantdifferences were found in patient or graft outcomes amongst the four groups. Multivariate analysis showed thatgroup 4 recipients might experience inferior 5-year graft function (β = -11.8, P = 0.037) when compared with group1.CONCLUSIONIn LDKT, long-term patient and graft outcomes are comparable amongst different combinations of standard vs ECdonors and recipients. These findings show the primary potential of living donor ECD to ECR kidney transplantationwith satisfying outcomes.
文摘BACKGROUND Heart transplantation is the last and best option for end-stage heart failure management.Early mortality rates have significantly decreased,enabling patients to survive longer with fewer complications,a trend observed even in our setting.The primary shared challenge has centered on achieving surgical success and immediate survival.The question arises about the medium-and long-term survival of patients with heart transplant in Mexico.AIM To present the results of the medium and long-term follow-up of heart transplant patients.METHODS This was a retrospective study of a single medical unit,and we selected patients who received heart transplants from July 21,1988 to September 30,2023.Selection criteria encompassed age,sex,and primary indication for heart transplantation across all groups.Patients with incomplete information or who died within 30 postoperative days were excluded.Data of primary pathology,ischemic,extracorporeal circulation,aortic cross-clamping times,length of ventilatory support,stay in postoperative therapy,hospitalization,and functional class were analyzed.RESULTS The causes of morbidity,mortality,and percentage of survival at 1,5,and 10 years were examined.Overall,257 heart transplants were performed during the study period.Of the total cases,22 with incomplete data and 47 who died within 30 postoperative days were excluded for the middle-and long-term survival analyses.Of the remaining 188 patients,heart transplantation was performed(males:146,females:42).The average age of the participants was 44.43±14.48 years.The primary indications included ischemic cardiomyopathy(42.55%)and dilated cardiomyopathy(39.36%).The mean durations of mechanical ventilator support,intensive care stay,and hospital stay were 57.55±103.50 hours,9.96±8.59 days,and 19.49±18.23 days,respectively.One-,five-,and ten-year survival rates were 90.7%,71.3%,and 60.3%,respectively.Of the patients,94%and 6%were in functional classes I and II,respectively.Infection and neurological hemorrhagic or ischemic stroke(26%)were the main causes of mortality in the first year.Subsequently,chronic rejection manifesting as graft vasculopathy increased in frequency(30%).CONCLUSION In our setting,heart transplantation yields medium-and long-term survival and quality of life outcomes comparable to those achieved by other international centers.
基金supported by the National Natural Science Foundation of China(No.12035020)National Key Scientific Instrument and Equipment Development Projects of China(No.42327802).
文摘The main scientific payload of Macao Science Satellite-1B is a solar soft X-ray detection unit.To obtain an accurate solar X-ray spectrum,we have designed low-noise,high-throughput electronics.Solar radiation is detected using a low-leakage silicon drift detector(SDD),which is cooled to-30℃.The SDD output is processed using two parallel shaping amplifiers with peaking times of 315 ns and 65 ns.The amplifiers are designed using two-pole multiple-feedback active low-pass filters optimized to achieve a Bessel response.The differential output of the shaping amplifier generates a bipolar signal.The phase of the differential stage is tuned to ensure zero crossing corresponding to the peak of the shaping amplifier.A high-speed switch is inserted between the shaping amplifier and the peak-hold capacitor,and the peak value is maintained by turning off the switch.Fast and slow peak-hold circuits share a common ADC via time-division multiplexing.Both peak values are sampled for space-background rejection.Traditional pile-up detection methods cannot distinguish pulses that overlap in a fast channel.In this study,the differential of the“fast shaping”is selected,enabling the distinction of events separated by as little as 65ns,which is crucial for solar flare detection.The energy resolution is measured to be 138 eV at 5.90 keV.The centroid drift is less than 3.6 eV between-5℃ and 20℃.Compared with other solar X-ray instruments,this study demonstrates improved energy resolution with a lower peaking time,indicating a higher solar flare detection capability.
基金supported by the National Natural Science Foundation of China(Nos.52275022,52175015 and U2037603)the Natural Science Foundation of Jiangsu Province,China(Nos.BK20222011 and BK20230093)the State Key Laboratory of Mechanics and Control for Aerospace Structures,China(No.MCAS-S-0223G01)。
文摘Piezoelectric active vibration control holds paramount importance in space structures.An embedded piezoelectric actuator with a sandwich configuration is proposed,which enhances control accuracy by integrating various components.Firstly,the electromechanical coupling characteristics of the actuator are revealed,and the model is established.Secondly,the equivalent model of a cylindrical cantilever beam is investigated as the object,and the feasibility of the vibration control of the actuator is verified by simulation.Finally,the prototype comprised of two actuators,which respectively use the proposed embedded actuators for producing the vibration and suppressing the vibration,is developed,and the measurement system is constructed.Experimental results demonstrate the excellent control efficiency in two orthogonal directions,achieving a minimum vibration amplitude control of 0.00102 mm and a maximum vibration control of-42.74 d B.The integrated structure offers fast response,lightness,adaptability,and high control efficiency,which is conducive to enhancing the vibration control.
文摘Asia, a major cradle of human civilizations,boasts three of the four ancient civilizations that developed a rich legacy of art, culture and scientific achievements over thousands of years. Since ancient times.
文摘General information Hepatobiliary&Pancreatic Diseases International is a journal published bimonthly in the English language by the First Afliated Hospital,Zhejiang University School of Medicine,Hangzhou,China.We welcome original research articles,review articles,editorials,and others from any part of the world.Manuscripts are reviewed by members of the international editorial board and our expert peer reviewers,then either accepted for publication or rejected by the chief editor.Manuscripts should be submitted via https://mc03.mamuscrlptcen tral.com/hbpdint.
