Transcatheter intervention allows to deal with multiple cardiovascular diseases1 in patients with impaired clinical conditions and burdened with multiple comorbidities,both with the advantage of planning number and mo...Transcatheter intervention allows to deal with multiple cardiovascular diseases1 in patients with impaired clinical conditions and burdened with multiple comorbidities,both with the advantage of planning number and modalities of the interventions and deciding,where possible,to realize them in a single session.Here we describe the case of a patient affected by severe aortic stenosis and associated cardiac comorbidities(coronary artery disease,atrial fibrillation and left appendage thrombosis)that needed a multimodal clinical and interventional strategy to lead him to the best clinical condition for performing transcatheter aortic valve implantation(TAVI).展开更多
Background Transcatheter left atrial appendage occlusion(LAAO)has become a suitable alternative to anticoagulation in patients with atrial fibrillation(AF).However,outcomes among patients age>75 years undergoing LA...Background Transcatheter left atrial appendage occlusion(LAAO)has become a suitable alternative to anticoagulation in patients with atrial fibrillation(AF).However,outcomes among patients age>75 years undergoing LAAO are lacking.Methods We included 723 consecutive patients with AF undergoing LAAO from August 2015 to March 2020.Patient data including clinical,laboratory,procedural characteristics,medications and outcomes were collected.The primary composite outcome was major adverse cardiac events(MACE)including mortality,stroke,bleeding and readmissions at 60-days.Results Mean age was 75±8 years and 434(60%)were males.Median CHA2DS2-VASc score was 4(IQR:4,5)points and median HASBLED score was 4(IQR:3,4)points.Composite MACE outcome was significantly higher among patients age>75 years in both unadjusted(17.1%vs.11.5%,P=0.03)and adjusted(Odds Ratio=1.59,95%CI:1.02-2.46,P=0.04)analysis.Composite MACE was primarily driven by higher all-cause mortality(1.3%vs.0,P=0.04)among patients age>75 years.The secondary outcome of procedural success was also lower among patients age>75 years(92.2%vs.96.2%,P=0.02).The occurrence of stroke(P=0.38),major bleeding(P=0.29)and readmissions(P=0.15)did not differ between patients age>75 years and less than 75years.Conclusion Patients age>75 years undergoing LAAO have worse outcomes primarily driven by higher all-cause mortality and are less likely to achieve procedural success.Future prospective studies evaluating these findings are warranted.展开更多
Scar formation resulting from burns or severe trauma can significantly compromise the structural integrity of skin and lead to permanent loss of skin appendages,ultimately impairing its normal physiological function.A...Scar formation resulting from burns or severe trauma can significantly compromise the structural integrity of skin and lead to permanent loss of skin appendages,ultimately impairing its normal physiological function.Accumulating evidence underscores the potential of targeted modulation of mechanical cues to enhance skin regeneration,promoting scarless repair by influencing the extracellular microenvironment and driving the phenotypic transitions.The field of skin repair and skin appendage regeneration has witnessed remarkable advancements in the utilization of biomaterials with distinct physical properties.However,a comprehensive understanding of the underlying mechanisms remains somewhat elusive,limiting the broader application of these innovations.In this review,we present two promising biomaterial-based mechanical approaches aimed at bolstering the regenerative capacity of compromised skin.The first approach involves leveraging biomaterials with specific biophysical properties to create an optimal scarless environment that supports cellular activities essential for regeneration.The second approach centers on harnessing mechanical forces exerted by biomaterials to enhance cellular plasticity,facilitating efficient cellular reprogramming and,consequently,promoting the regeneration of skin appendages.In summary,the manipulation of mechanical cues using biomaterial-based strategies holds significant promise as a supplementary approach for achieving scarless wound healing,coupled with the restoration of multiple skin appendage functions.展开更多
Introduction: the left atrial appendage, a dormant embryonic vestige, would play a major role in cardiac hemodynamic changes, volume homeostasis and thrombi formation. It, therefore constitutes a therapeutic target. I...Introduction: the left atrial appendage, a dormant embryonic vestige, would play a major role in cardiac hemodynamic changes, volume homeostasis and thrombi formation. It, therefore constitutes a therapeutic target. Its morphology is extremely variable. Objective: it consisted on determining the morphological variations of the left auricle as well as their interest in the prevention of thrombi in the Senegalese. Material and Method: This study was conducted by dissecting 36 fresh hearts from Senegalese anatomical subjects with a sampling of the left atrial appendage, including specimens with normal morphological appearance. Their morphology was studied using the fresh and frozen plaster molding method. The data obtained were analyzed statistically. Results: the average age of the subjects was 33 years, with a sex ratio of 1.06, the cauliflower shape was dominant with 57% of cases and the cactus shape (4%) was less frequent. The cauliflower shape presented a clear angulation compared to the others without statistically significant differences according to age. Conclusion: This work showed a great morphological variability of the left atrial appendage. It can provide an update on the specificity of Senegalese. Taking these variations into account is important in the safe management of hemodynamic conditions and the improvement of the management of recurrent strokes.展开更多
This paper addresses the problem of a viscoelastic Euler-Bernoulli beam under the influence of a constant velocity moving mass and different types of appendages.Four types of boundary conditions are considered:pinned-...This paper addresses the problem of a viscoelastic Euler-Bernoulli beam under the influence of a constant velocity moving mass and different types of appendages.Four types of boundary conditions are considered:pinned-pinned,fixed-pinned,fixed-free(or cantilever),and fixed-fixed.Appendages considered include lumped masses,dampers,and springs.The modal decomposition method is employed to derive the equation of motion of the beam,for which an analytical closed-form expression of the dynamic vibration response is generated.The proposed method enables the study of the effect of a single appendage or a combination of the three types of appendages on the non-dimensional dynamic response of the beam.Numerical examples are presented to illustrate the effects of these appendages and compare them to the reference cases of a beam with no appendages.The results demonstrate the importance of considering these parameters in the design of structures.The proposed method is compared to other techniques in the literature and found to be advantageous due to its direct approach.The method also offers a versatile tool for investigating various configurations,aiding in engineering design and structural analysis for which establishing a precise prediction of beam vibrations is crucial.展开更多
Autotomy of appendages is a self-protection mechanism in crustaceans,which is defined as the reflexive loss of a limb in response to predation,competition,or other environmental factors.Single-limb injuries were the m...Autotomy of appendages is a self-protection mechanism in crustaceans,which is defined as the reflexive loss of a limb in response to predation,competition,or other environmental factors.Single-limb injuries were the most common among the species surveyed in the present study,and the chelicerae were the most frequently lost appendages.After autotomy,hormones and signaling pathways are altered.Loss of limbs can affect foraging efficiency,although cheliped loss may be compensated by shifting to alternative prey or using both motor and oral appendages.In heterogeneous species,the loss of the major chelae may affect the selectivity of feeding.Autotomy can affect crustacean growth by reducing size increases at molting and altering the timing of ecdysis.In commercial production,removing chelicerae is an effective strategy to reduce cannibalism,and production of soft-shell crabs can be increased via autotomy.After autotomy,a new limb will regrow through regeneration and molting.This process involves the regulation of hormones,regrowth of nerves,and a number of signaling pathways that include the Wnt/β-catenin signaling pathway and transforming growth factorβsignaling pathway.Crustaceans are somewhat different from vertebrates in terms of regeneration.This review provides theoretical guidance about autotomy and regeneration applied in artificial aquaculture,and we offer several suggestions for future research on autotomy and regeneration in crustaceans.展开更多
BACKGROUND There are very few cases of cardiac occluder detachment,and it is rare to completely remove the occluder using interventional methods without undergoing thoracotomy surgery after detachment.This case innova...BACKGROUND There are very few cases of cardiac occluder detachment,and it is rare to completely remove the occluder using interventional methods without undergoing thoracotomy surgery after detachment.This case innovatively used ultrasound guidance combined with digital subtraction angiography(DSA)to completely remove the occluder,accumulating some experience.CASE SUMMARY The patient underwent left atrial appendage occlusion surgery in our hospital due to atrial fibrillation.After the surgery,the occluder fell off and became free in the left ventricle,which is very dangerous.We innovatively used ultrasound guidance,combined with DSA,and interventional surgery to successfully capture the free occluder using a catcher,completely remove it,and then re implant a new left atrial appendage occluder.After the surgery,the patient recovered very well.CONCLUSION The size selection of the occluder is slightly conservative,and the shape of the left atrial appendage opening is irregular.展开更多
BACKGROUND Inflammatory indices derived from complete blood tests have been reported to be associated with poor outcomes in patients with atrial fibrillation(AF).The data about the relationship between inflammatory in...BACKGROUND Inflammatory indices derived from complete blood tests have been reported to be associated with poor outcomes in patients with atrial fibrillation(AF).The data about the relationship between inflammatory indices and left atrial appendage thrombus(LAAT)or dense spontaneous echo contrast(SEC)are limited.AIM To explore the value of inflammatory indices for predicting the presence of LAAT or dense SEC in nonvalvular AF patients.METHODS A total of 406 patients with nonvalvular AF who underwent transesophageal echocardiography were included and divided into two groups based on the presence(study group)or absence(control group)of LAAT or dense SEC.Inflammatory indices,including the neutrophil-to-lymphocyte ratio(NLR),platelet–tolymphocyte ratio(PLR),and lymphocyte-to-monocyte ratio(LMR),were calculated from complete blood analysis.The associations of inflammatory indices RESULTS LAAT and dense SEC were detected in 11(2.7%)and 42(10.3%)patients,respectively.The PLR only showed an association with LAAT/dense SEC in the univariate model.Elevated NLR(odds ratio[OR]=1.48,95%confidence interval[CI]:1.11-1.98,P=0.007)and reduced LMR(OR=0.59,95%CI:0.41-0.83,P=0.003)were found to be independent risk factors for the presence of LAAT/dense SEC.The areas under the NLR and LMR curves for predicting LAAT/dense SEC were 0.73(95%CI:0.66-0.80,P<0.001)and 0.73(95%CI:0.65-0.81,P<0.001),respectively,while the cutoff values were 2.8(sensitivity:69.8%;specificity:64.0%)and 2.4(sensitivity:71.7%;specificity:60.6%),respectively.CONCLUSION Increased NLR and decreased LMR may predict LAAT/dense SEC in patients with nonvalvular AF.展开更多
Addressing the ongoing challenge of enhancing propulsion efficiency in rim-driven thrusters(RDTs),a novel energy-saving appendage was designed to mitigate energy dissipation and improve efficiency.Computational fluid ...Addressing the ongoing challenge of enhancing propulsion efficiency in rim-driven thrusters(RDTs),a novel energy-saving appendage was designed to mitigate energy dissipation and improve efficiency.Computational fluid dynamics was utilized to examine the disparities in openwater performance between RDTs with and without this appendage.The Reynolds-Averaged Navier–Stokes equations were solved using the Moving Reference Frame approach within the established STAR-CCM+software.The accuracy of these methodologies was confirmed through a comparison of numerical simulations with experimental data.A meticulous analysis evaluated the alterations in propulsion efficiency of RDTs pre-and post-appendage integration across various advance coefficients.Additionally,a comprehensive assessment of thrust and torque coefficient distributions facilitated a comprehensive understanding of the appendage’s energy-saving potential.Results demonstrated that the new appendage diminishes the diffusive wake behind the rotor disk,fostering a more uniform flow distribution.A notable reduction in the lowpressure zone on the rotor blade’s thrust side was observed,accompanied by an elevation in the high-pressure area.This generated a distinct pressure disparity between the blade’s thrust and suction sides,mitigating the low-pressure region at the blade tip and reducing the likelihood of cavitation.The manuscript further elucidates the rationale behind these alterations,providing detailed insights into flow field dynamics.展开更多
In engineering applications (Like an ocean riser), fluid flow around bluff bodies generates substantial resistance, which can jeopardize structural integrity, lifespan, and escalate resource consumption. Therefore, em...In engineering applications (Like an ocean riser), fluid flow around bluff bodies generates substantial resistance, which can jeopardize structural integrity, lifespan, and escalate resource consumption. Therefore, employing drag reduction measures becomes particularly crucial. This paper employs the immersed boundary method to investigate the impact of transversely oriented appendage plate flexibility on the drag of cylinders under different Reynolds numbers and distances. The results indicate that flexible appendage plate exerts drag reduction effects on the downstream cylinder, with this effect gradually diminishing as Reynolds numbers increase. At identical Reynolds numbers, the drag reduction effect initially increases and then decreases with distance, with the optimal drag reduction distance observed at D = 2.5. Compared to cylinders without appendage plate, the maximum drag reduction achieved is 30.551%. Addressing the drag reduction issue in cylinders holds significant importance for ensuring engineering structural integrity, enhancing engineering efficiency, and developing novel underwater towing systems.展开更多
AIM To evaluate the safety and efficacy of surgical left atrial appendage occlusion(s-LAAO)during concomitant cardiac surgery.METHODS We performed a comprehensive literature search through May 31 st 2018 for all eligi...AIM To evaluate the safety and efficacy of surgical left atrial appendage occlusion(s-LAAO)during concomitant cardiac surgery.METHODS We performed a comprehensive literature search through May 31 st 2018 for all eligible studies comparing s-LAAO vs no occlusion in patients undergoing cardiac surgery.Clinical outcomes during follow-up included:embolic events,stroke,all-cause mortality,atrial fibrillation(AF),reoperation for bleeding and postoperative complications.We further stratified the analysis based on propensity matched studies and AF predominance.RESULTS Twelve studies(n=40107)met the inclusion criteria.s-LAAO was associated with lower risk of embolic events(OR:0.63,95%CI:0.53-0.76;P<0.001)and stroke(OR:0.68,95%CI:0.57-0.82;P<0.0001).Stratified analysis demonstrated this association was more prominent in the AF predominant strata.There was no significant difference in the incidence risk of allcause mortality,AF,and reoperation for bleeding and postoperative complications.CONCLUSION Concomitant s-LAAO during cardiac surgery was associated with lower risk of follow-up thromboembolic events and stroke,especially in those with AF without significant increase in adverse events.Further randomized trials to evaluate long-term benefits of s-LAAO are warranted.展开更多
Attitude maneuver of liquid-filled spacecraft with an appendage as a cantilever beam by momentum wheel is studied. The dynamic equations are derived by conserva- tion of angular momentum and force equilibrium principl...Attitude maneuver of liquid-filled spacecraft with an appendage as a cantilever beam by momentum wheel is studied. The dynamic equations are derived by conserva- tion of angular momentum and force equilibrium principle. A feedback control strategy of the momentum wheel is ap- plied for the attitude maneuver. The residual nutation of the spacecraft in maneuver process changes with some chosen parameters, such as steady state time, locations of the liq- uid container and the appendage, and appendage parame- ters. The results indicate that locations in the second and fourth quadrants of the body-fixed coordinate system and the second quadrant of the wall of the main body are better choices for.placing the liquid containers and the appendage than other locations if they can be placed randomly. Higher density and thicker cross section are better for lowering the residual nutation if they can be changed. Light appendage can be modeled as a rigid body, which results in a larger residual nutation than a flexible model though. The resid- ual nutation decreases with increasing absolute value of the initial sloshing angular height.展开更多
Atrial fibrillation （AF） is the most common cardiac ar-rhythmia in clinical practice with an increasing incidenceand prevalence. With ageing, the risk of thromboembolicand hemorrhagic events increases dramatically. ...Atrial fibrillation （AF） is the most common cardiac ar-rhythmia in clinical practice with an increasing incidenceand prevalence. With ageing, the risk of thromboembolicand hemorrhagic events increases dramatically. As it hasbeen reported previously, 3-year survival rate among pa-tients with AF over 75 years of age after stroke is less than50%, and almost 90% of those patients will remain dis-abled.展开更多
Heart rhythm disturbances become of special importancewhen patients reach a senior age. Atrial fibrillation （AF） isthe most prevalent arrhythmia among the old age groups,and its impact on morbidity and mortality bec...Heart rhythm disturbances become of special importancewhen patients reach a senior age. Atrial fibrillation （AF） isthe most prevalent arrhythmia among the old age groups,and its impact on morbidity and mortality becomes of para-mount significance. In this population, AF is responsible forsignificant amount of thromboembolic cerebrovascularevents, especially for disabling and fatal strokes, Follow-ing announcement of the special issue of the Journal of Geri-atric Cardiology devoted to heart rhythm disorders in theelderly, a number of submissions have been received withAF as the major topic of authors＇ researches.展开更多
Patient with atrial fibrillation(AF) are at risk of developing stroke with the left atrial appendage(LAA) being the most common site for thrombus formation. If left untreated, AF is associated with 4 to 5 folds increa...Patient with atrial fibrillation(AF) are at risk of developing stroke with the left atrial appendage(LAA) being the most common site for thrombus formation. If left untreated, AF is associated with 4 to 5 folds increase in the risk of ischemic stroke in all age groups. About 5% to 15% of AF patients have atrial thrombi on transesophageal echocardiography, and 91% of those thrombi are located in the LAA in patient with nonrheumatic AF. Although oral anticoagulants are the gold-standard treatment for stroke prevention in patients with non-valvular AF,some patients are at high risk of bleeding and deemed not candidates for anticoagulation. Therefore, LAA occlusion(LAAO) has emerged as alternative approach for stroke prevention in those patients. Surgical LAAO is associated with high rate of unsuccessful closure and recommended only in patients with AF and undergoing cardiac surgery. Percutaneous LAAO uses transvenous access with trans-septal puncture and was first tested using the PLAATO device.Watchman is the most common and only Food and Drug Administration(FDA)approved device for LAAO. LAAO using Watchman device is non-inferior to warfarin therapy in preventing ischemic stroke/systemic thromboembolism.However, it is associated with lower rates of hemorrhagic stroke, bleeding and death. Amplatzer is another successful LAAO device that has CE mark and is waiting for FDA approval. Optimal antithrombotic therapy post LAAO is still under debate and highly patient-specific. The aim of this paper is to systematically review the current literature to evaluate the efficacy and safety of different LAAO devices.展开更多
Transcatheter closure of the left atrial appendage has been developed as an alternative to chronic oral anticoagulation for stroke prevention in patients with atrial fibrillation, and as a primary therapy for patients...Transcatheter closure of the left atrial appendage has been developed as an alternative to chronic oral anticoagulation for stroke prevention in patients with atrial fibrillation, and as a primary therapy for patients with contraindications to chronic oral anticoagulation. The promise of this new intervention compared with warfarin has been supported by several, small studies and two pivotal randomized trial with the Watchman Device. The results regarding risk reduction for stroke have been favourable although acute complications were not infrequent. Procedural complications, which are mainly related to transseptal puncture and device implantation, include air embolism, pericardial effusions/tamponade and device embolization. Knowledge of nature, management and prevention of complications should minimize the risk of complications and allow transcatheter left atrial appendage closure to emerge as a therapeutic option for patients with atrial fibrillation at risk for cardioembolic stroke.展开更多
An atrial septal defect (ASD) may cause right heart dysfunction, pulmonary hypertension and atrial fibrillation (AF), and atrial septal defect occlusion (ASDO) is the first choice for treating secundum defects when th...An atrial septal defect (ASD) may cause right heart dysfunction, pulmonary hypertension and atrial fibrillation (AF), and atrial septal defect occlusion (ASDO) is the first choice for treating secundum defects when the morphology permits. ASD and AF frequently coexist, and the risk of AF and stroke persists after ASDO.[1] In recent years, left atrial appendage occlusion (LAAO) has been recognized as an effective treatment for stroke prevention in nonvalvular AF patients with a high risk of stroke, systemic embolism and bleeding who are unwilling to take oral anticoagulants or cannot tolerate them.展开更多
This paper is mainly concerned with the coupling dynamic analysis of a complex spacecraft consisting of one main rigid platform, multiple liquid-filled cylindrical tanks, and a number of flexible appendages. Firstly, ...This paper is mainly concerned with the coupling dynamic analysis of a complex spacecraft consisting of one main rigid platform, multiple liquid-filled cylindrical tanks, and a number of flexible appendages. Firstly, the carrier potential function equations of liquid in the tanks are deduced according to the wall boundary conditions. Through employ- ing the Fourier-Bessel series expansion method, the dynamic boundaries conditions on a curved free-surface under a low-gravity environment are transformed to general simple differential equations and the rigid-liquid coupled sloshing dynamic state equations of liquid in tanks are obtained. The state vectors of rigid-liquid coupled equations are composed with the modal coordinates of the relative potential func- tion and the modal coordinates of wave height. Based on the B ernoulli-Euler beam theory and the D＇Alembert＇s prin- ciple, the rigid-flexible coupled dynamic state equations of flexible appendages are directly derived, and the coordi- nate transform matrixes of maneuvering flexible appendages are precisely computed as time-varying. Then, the cou- pling dynamics state equations of the overall system of the spacecraft are modularly built by means of the Lagrange＇s equations in terms of quasi-coordinates. Lastly, the cou-piing dynamic performances of a typical complex spacecraft are studied. The availability and reliability of the presented method are also confirmed.展开更多
Non-valvular atrial fibrillation is associated with a significantly increased risk of embolic stroke due to blood clot forming predominantly in the left atrial appendage(LAA). Preventive measures to avoid embolic even...Non-valvular atrial fibrillation is associated with a significantly increased risk of embolic stroke due to blood clot forming predominantly in the left atrial appendage(LAA). Preventive measures to avoid embolic events are permanent administration of anticoagulants or surgical closure of the LAA. Various clinical trials provide evidence about safety, effectiveness and therapeutic success of LAA occlusion using various cardiac occluder devices. The use of such implants for interventional closure of the LAA is likely to become a valuable alternative for stroke prevention, especially in patients with contraindication for oral anticoagulation as safety, clinical benefit and cost-effectiveness of LAA occlusion has recently been demonstrated.展开更多
文摘Transcatheter intervention allows to deal with multiple cardiovascular diseases1 in patients with impaired clinical conditions and burdened with multiple comorbidities,both with the advantage of planning number and modalities of the interventions and deciding,where possible,to realize them in a single session.Here we describe the case of a patient affected by severe aortic stenosis and associated cardiac comorbidities(coronary artery disease,atrial fibrillation and left appendage thrombosis)that needed a multimodal clinical and interventional strategy to lead him to the best clinical condition for performing transcatheter aortic valve implantation(TAVI).
文摘Background Transcatheter left atrial appendage occlusion(LAAO)has become a suitable alternative to anticoagulation in patients with atrial fibrillation(AF).However,outcomes among patients age>75 years undergoing LAAO are lacking.Methods We included 723 consecutive patients with AF undergoing LAAO from August 2015 to March 2020.Patient data including clinical,laboratory,procedural characteristics,medications and outcomes were collected.The primary composite outcome was major adverse cardiac events(MACE)including mortality,stroke,bleeding and readmissions at 60-days.Results Mean age was 75±8 years and 434(60%)were males.Median CHA2DS2-VASc score was 4(IQR:4,5)points and median HASBLED score was 4(IQR:3,4)points.Composite MACE outcome was significantly higher among patients age>75 years in both unadjusted(17.1%vs.11.5%,P=0.03)and adjusted(Odds Ratio=1.59,95%CI:1.02-2.46,P=0.04)analysis.Composite MACE was primarily driven by higher all-cause mortality(1.3%vs.0,P=0.04)among patients age>75 years.The secondary outcome of procedural success was also lower among patients age>75 years(92.2%vs.96.2%,P=0.02).The occurrence of stroke(P=0.38),major bleeding(P=0.29)and readmissions(P=0.15)did not differ between patients age>75 years and less than 75years.Conclusion Patients age>75 years undergoing LAAO have worse outcomes primarily driven by higher all-cause mortality and are less likely to achieve procedural success.Future prospective studies evaluating these findings are warranted.
基金supported in part by the National Nature Science Foundation of China(92268206,81830064)the CAMS Innovation Fund for Medical Sciences(CIFMS,2019-I2M-5-059)+4 种基金the Military Medical Research Projects(145AKJ260015000X,2022-JCJQ-ZB-09600)the Military Key Basic Research of Foundational Strengthening Program(2020-JCJQ-ZD-256-021)the Science Foundation of National Defense Science and Technology for Excellent Young(2022-JCJQ-ZQ-017)the Military Medical Research and Development Projects(AWS17J005,2019-126)the Specific Research Fund of The Innovation Platform for Academicians of Hainan Province(YSPTZX202317).
文摘Scar formation resulting from burns or severe trauma can significantly compromise the structural integrity of skin and lead to permanent loss of skin appendages,ultimately impairing its normal physiological function.Accumulating evidence underscores the potential of targeted modulation of mechanical cues to enhance skin regeneration,promoting scarless repair by influencing the extracellular microenvironment and driving the phenotypic transitions.The field of skin repair and skin appendage regeneration has witnessed remarkable advancements in the utilization of biomaterials with distinct physical properties.However,a comprehensive understanding of the underlying mechanisms remains somewhat elusive,limiting the broader application of these innovations.In this review,we present two promising biomaterial-based mechanical approaches aimed at bolstering the regenerative capacity of compromised skin.The first approach involves leveraging biomaterials with specific biophysical properties to create an optimal scarless environment that supports cellular activities essential for regeneration.The second approach centers on harnessing mechanical forces exerted by biomaterials to enhance cellular plasticity,facilitating efficient cellular reprogramming and,consequently,promoting the regeneration of skin appendages.In summary,the manipulation of mechanical cues using biomaterial-based strategies holds significant promise as a supplementary approach for achieving scarless wound healing,coupled with the restoration of multiple skin appendage functions.
文摘Introduction: the left atrial appendage, a dormant embryonic vestige, would play a major role in cardiac hemodynamic changes, volume homeostasis and thrombi formation. It, therefore constitutes a therapeutic target. Its morphology is extremely variable. Objective: it consisted on determining the morphological variations of the left auricle as well as their interest in the prevention of thrombi in the Senegalese. Material and Method: This study was conducted by dissecting 36 fresh hearts from Senegalese anatomical subjects with a sampling of the left atrial appendage, including specimens with normal morphological appearance. Their morphology was studied using the fresh and frozen plaster molding method. The data obtained were analyzed statistically. Results: the average age of the subjects was 33 years, with a sex ratio of 1.06, the cauliflower shape was dominant with 57% of cases and the cactus shape (4%) was less frequent. The cauliflower shape presented a clear angulation compared to the others without statistically significant differences according to age. Conclusion: This work showed a great morphological variability of the left atrial appendage. It can provide an update on the specificity of Senegalese. Taking these variations into account is important in the safe management of hemodynamic conditions and the improvement of the management of recurrent strokes.
文摘This paper addresses the problem of a viscoelastic Euler-Bernoulli beam under the influence of a constant velocity moving mass and different types of appendages.Four types of boundary conditions are considered:pinned-pinned,fixed-pinned,fixed-free(or cantilever),and fixed-fixed.Appendages considered include lumped masses,dampers,and springs.The modal decomposition method is employed to derive the equation of motion of the beam,for which an analytical closed-form expression of the dynamic vibration response is generated.The proposed method enables the study of the effect of a single appendage or a combination of the three types of appendages on the non-dimensional dynamic response of the beam.Numerical examples are presented to illustrate the effects of these appendages and compare them to the reference cases of a beam with no appendages.The results demonstrate the importance of considering these parameters in the design of structures.The proposed method is compared to other techniques in the literature and found to be advantageous due to its direct approach.The method also offers a versatile tool for investigating various configurations,aiding in engineering design and structural analysis for which establishing a precise prediction of beam vibrations is crucial.
基金funded by the National Natural Science Foundation of China(Nos.32172993,42106104)the Ningbo Provincial Natural Science Foundation of China(No.202003N4181).
文摘Autotomy of appendages is a self-protection mechanism in crustaceans,which is defined as the reflexive loss of a limb in response to predation,competition,or other environmental factors.Single-limb injuries were the most common among the species surveyed in the present study,and the chelicerae were the most frequently lost appendages.After autotomy,hormones and signaling pathways are altered.Loss of limbs can affect foraging efficiency,although cheliped loss may be compensated by shifting to alternative prey or using both motor and oral appendages.In heterogeneous species,the loss of the major chelae may affect the selectivity of feeding.Autotomy can affect crustacean growth by reducing size increases at molting and altering the timing of ecdysis.In commercial production,removing chelicerae is an effective strategy to reduce cannibalism,and production of soft-shell crabs can be increased via autotomy.After autotomy,a new limb will regrow through regeneration and molting.This process involves the regulation of hormones,regrowth of nerves,and a number of signaling pathways that include the Wnt/β-catenin signaling pathway and transforming growth factorβsignaling pathway.Crustaceans are somewhat different from vertebrates in terms of regeneration.This review provides theoretical guidance about autotomy and regeneration applied in artificial aquaculture,and we offer several suggestions for future research on autotomy and regeneration in crustaceans.
文摘BACKGROUND There are very few cases of cardiac occluder detachment,and it is rare to completely remove the occluder using interventional methods without undergoing thoracotomy surgery after detachment.This case innovatively used ultrasound guidance combined with digital subtraction angiography(DSA)to completely remove the occluder,accumulating some experience.CASE SUMMARY The patient underwent left atrial appendage occlusion surgery in our hospital due to atrial fibrillation.After the surgery,the occluder fell off and became free in the left ventricle,which is very dangerous.We innovatively used ultrasound guidance,combined with DSA,and interventional surgery to successfully capture the free occluder using a catcher,completely remove it,and then re implant a new left atrial appendage occluder.After the surgery,the patient recovered very well.CONCLUSION The size selection of the occluder is slightly conservative,and the shape of the left atrial appendage opening is irregular.
基金Public Welfare Technology Project of Ningbo Science and Technology Bureau,No.2023S140Medical Health Science and Technology Project of Zhejiang Province Health Commission,No.2024KY1518.
文摘BACKGROUND Inflammatory indices derived from complete blood tests have been reported to be associated with poor outcomes in patients with atrial fibrillation(AF).The data about the relationship between inflammatory indices and left atrial appendage thrombus(LAAT)or dense spontaneous echo contrast(SEC)are limited.AIM To explore the value of inflammatory indices for predicting the presence of LAAT or dense SEC in nonvalvular AF patients.METHODS A total of 406 patients with nonvalvular AF who underwent transesophageal echocardiography were included and divided into two groups based on the presence(study group)or absence(control group)of LAAT or dense SEC.Inflammatory indices,including the neutrophil-to-lymphocyte ratio(NLR),platelet–tolymphocyte ratio(PLR),and lymphocyte-to-monocyte ratio(LMR),were calculated from complete blood analysis.The associations of inflammatory indices RESULTS LAAT and dense SEC were detected in 11(2.7%)and 42(10.3%)patients,respectively.The PLR only showed an association with LAAT/dense SEC in the univariate model.Elevated NLR(odds ratio[OR]=1.48,95%confidence interval[CI]:1.11-1.98,P=0.007)and reduced LMR(OR=0.59,95%CI:0.41-0.83,P=0.003)were found to be independent risk factors for the presence of LAAT/dense SEC.The areas under the NLR and LMR curves for predicting LAAT/dense SEC were 0.73(95%CI:0.66-0.80,P<0.001)and 0.73(95%CI:0.65-0.81,P<0.001),respectively,while the cutoff values were 2.8(sensitivity:69.8%;specificity:64.0%)and 2.4(sensitivity:71.7%;specificity:60.6%),respectively.CONCLUSION Increased NLR and decreased LMR may predict LAAT/dense SEC in patients with nonvalvular AF.
文摘Addressing the ongoing challenge of enhancing propulsion efficiency in rim-driven thrusters(RDTs),a novel energy-saving appendage was designed to mitigate energy dissipation and improve efficiency.Computational fluid dynamics was utilized to examine the disparities in openwater performance between RDTs with and without this appendage.The Reynolds-Averaged Navier–Stokes equations were solved using the Moving Reference Frame approach within the established STAR-CCM+software.The accuracy of these methodologies was confirmed through a comparison of numerical simulations with experimental data.A meticulous analysis evaluated the alterations in propulsion efficiency of RDTs pre-and post-appendage integration across various advance coefficients.Additionally,a comprehensive assessment of thrust and torque coefficient distributions facilitated a comprehensive understanding of the appendage’s energy-saving potential.Results demonstrated that the new appendage diminishes the diffusive wake behind the rotor disk,fostering a more uniform flow distribution.A notable reduction in the lowpressure zone on the rotor blade’s thrust side was observed,accompanied by an elevation in the high-pressure area.This generated a distinct pressure disparity between the blade’s thrust and suction sides,mitigating the low-pressure region at the blade tip and reducing the likelihood of cavitation.The manuscript further elucidates the rationale behind these alterations,providing detailed insights into flow field dynamics.
文摘In engineering applications (Like an ocean riser), fluid flow around bluff bodies generates substantial resistance, which can jeopardize structural integrity, lifespan, and escalate resource consumption. Therefore, employing drag reduction measures becomes particularly crucial. This paper employs the immersed boundary method to investigate the impact of transversely oriented appendage plate flexibility on the drag of cylinders under different Reynolds numbers and distances. The results indicate that flexible appendage plate exerts drag reduction effects on the downstream cylinder, with this effect gradually diminishing as Reynolds numbers increase. At identical Reynolds numbers, the drag reduction effect initially increases and then decreases with distance, with the optimal drag reduction distance observed at D = 2.5. Compared to cylinders without appendage plate, the maximum drag reduction achieved is 30.551%. Addressing the drag reduction issue in cylinders holds significant importance for ensuring engineering structural integrity, enhancing engineering efficiency, and developing novel underwater towing systems.
基金Supported by no external funding.Dr.Benditt is supported in part by a grant from the Dr.Earl E Bakken family in support of heart-brain research
文摘AIM To evaluate the safety and efficacy of surgical left atrial appendage occlusion(s-LAAO)during concomitant cardiac surgery.METHODS We performed a comprehensive literature search through May 31 st 2018 for all eligible studies comparing s-LAAO vs no occlusion in patients undergoing cardiac surgery.Clinical outcomes during follow-up included:embolic events,stroke,all-cause mortality,atrial fibrillation(AF),reoperation for bleeding and postoperative complications.We further stratified the analysis based on propensity matched studies and AF predominance.RESULTS Twelve studies(n=40107)met the inclusion criteria.s-LAAO was associated with lower risk of embolic events(OR:0.63,95%CI:0.53-0.76;P<0.001)and stroke(OR:0.68,95%CI:0.57-0.82;P<0.0001).Stratified analysis demonstrated this association was more prominent in the AF predominant strata.There was no significant difference in the incidence risk of allcause mortality,AF,and reoperation for bleeding and postoperative complications.CONCLUSION Concomitant s-LAAO during cardiac surgery was associated with lower risk of follow-up thromboembolic events and stroke,especially in those with AF without significant increase in adverse events.Further randomized trials to evaluate long-term benefits of s-LAAO are warranted.
基金supported by the National Natural Science Foundation of China (11072030)
文摘Attitude maneuver of liquid-filled spacecraft with an appendage as a cantilever beam by momentum wheel is studied. The dynamic equations are derived by conserva- tion of angular momentum and force equilibrium principle. A feedback control strategy of the momentum wheel is ap- plied for the attitude maneuver. The residual nutation of the spacecraft in maneuver process changes with some chosen parameters, such as steady state time, locations of the liq- uid container and the appendage, and appendage parame- ters. The results indicate that locations in the second and fourth quadrants of the body-fixed coordinate system and the second quadrant of the wall of the main body are better choices for.placing the liquid containers and the appendage than other locations if they can be placed randomly. Higher density and thicker cross section are better for lowering the residual nutation if they can be changed. Light appendage can be modeled as a rigid body, which results in a larger residual nutation than a flexible model though. The resid- ual nutation decreases with increasing absolute value of the initial sloshing angular height.
文摘Atrial fibrillation （AF） is the most common cardiac ar-rhythmia in clinical practice with an increasing incidenceand prevalence. With ageing, the risk of thromboembolicand hemorrhagic events increases dramatically. As it hasbeen reported previously, 3-year survival rate among pa-tients with AF over 75 years of age after stroke is less than50%, and almost 90% of those patients will remain dis-abled.
文摘Heart rhythm disturbances become of special importancewhen patients reach a senior age. Atrial fibrillation （AF） isthe most prevalent arrhythmia among the old age groups,and its impact on morbidity and mortality becomes of para-mount significance. In this population, AF is responsible forsignificant amount of thromboembolic cerebrovascularevents, especially for disabling and fatal strokes, Follow-ing announcement of the special issue of the Journal of Geri-atric Cardiology devoted to heart rhythm disorders in theelderly, a number of submissions have been received withAF as the major topic of authors＇ researches.
文摘Patient with atrial fibrillation(AF) are at risk of developing stroke with the left atrial appendage(LAA) being the most common site for thrombus formation. If left untreated, AF is associated with 4 to 5 folds increase in the risk of ischemic stroke in all age groups. About 5% to 15% of AF patients have atrial thrombi on transesophageal echocardiography, and 91% of those thrombi are located in the LAA in patient with nonrheumatic AF. Although oral anticoagulants are the gold-standard treatment for stroke prevention in patients with non-valvular AF,some patients are at high risk of bleeding and deemed not candidates for anticoagulation. Therefore, LAA occlusion(LAAO) has emerged as alternative approach for stroke prevention in those patients. Surgical LAAO is associated with high rate of unsuccessful closure and recommended only in patients with AF and undergoing cardiac surgery. Percutaneous LAAO uses transvenous access with trans-septal puncture and was first tested using the PLAATO device.Watchman is the most common and only Food and Drug Administration(FDA)approved device for LAAO. LAAO using Watchman device is non-inferior to warfarin therapy in preventing ischemic stroke/systemic thromboembolism.However, it is associated with lower rates of hemorrhagic stroke, bleeding and death. Amplatzer is another successful LAAO device that has CE mark and is waiting for FDA approval. Optimal antithrombotic therapy post LAAO is still under debate and highly patient-specific. The aim of this paper is to systematically review the current literature to evaluate the efficacy and safety of different LAAO devices.
文摘Transcatheter closure of the left atrial appendage has been developed as an alternative to chronic oral anticoagulation for stroke prevention in patients with atrial fibrillation, and as a primary therapy for patients with contraindications to chronic oral anticoagulation. The promise of this new intervention compared with warfarin has been supported by several, small studies and two pivotal randomized trial with the Watchman Device. The results regarding risk reduction for stroke have been favourable although acute complications were not infrequent. Procedural complications, which are mainly related to transseptal puncture and device implantation, include air embolism, pericardial effusions/tamponade and device embolization. Knowledge of nature, management and prevention of complications should minimize the risk of complications and allow transcatheter left atrial appendage closure to emerge as a therapeutic option for patients with atrial fibrillation at risk for cardioembolic stroke.
文摘An atrial septal defect (ASD) may cause right heart dysfunction, pulmonary hypertension and atrial fibrillation (AF), and atrial septal defect occlusion (ASDO) is the first choice for treating secundum defects when the morphology permits. ASD and AF frequently coexist, and the risk of AF and stroke persists after ASDO.[1] In recent years, left atrial appendage occlusion (LAAO) has been recognized as an effective treatment for stroke prevention in nonvalvular AF patients with a high risk of stroke, systemic embolism and bleeding who are unwilling to take oral anticoagulants or cannot tolerate them.
基金project was supported by the National Natural Science Foundation of China (Grants 11472041, 11302244, 11532002)Guangxi Natural Science Foundation (2015GXNSFBA 139013)
文摘This paper is mainly concerned with the coupling dynamic analysis of a complex spacecraft consisting of one main rigid platform, multiple liquid-filled cylindrical tanks, and a number of flexible appendages. Firstly, the carrier potential function equations of liquid in the tanks are deduced according to the wall boundary conditions. Through employ- ing the Fourier-Bessel series expansion method, the dynamic boundaries conditions on a curved free-surface under a low-gravity environment are transformed to general simple differential equations and the rigid-liquid coupled sloshing dynamic state equations of liquid in tanks are obtained. The state vectors of rigid-liquid coupled equations are composed with the modal coordinates of the relative potential func- tion and the modal coordinates of wave height. Based on the B ernoulli-Euler beam theory and the D＇Alembert＇s prin- ciple, the rigid-flexible coupled dynamic state equations of flexible appendages are directly derived, and the coordi- nate transform matrixes of maneuvering flexible appendages are precisely computed as time-varying. Then, the cou- pling dynamics state equations of the overall system of the spacecraft are modularly built by means of the Lagrange＇s equations in terms of quasi-coordinates. Lastly, the cou-piing dynamic performances of a typical complex spacecraft are studied. The availability and reliability of the presented method are also confirmed.
文摘Non-valvular atrial fibrillation is associated with a significantly increased risk of embolic stroke due to blood clot forming predominantly in the left atrial appendage(LAA). Preventive measures to avoid embolic events are permanent administration of anticoagulants or surgical closure of the LAA. Various clinical trials provide evidence about safety, effectiveness and therapeutic success of LAA occlusion using various cardiac occluder devices. The use of such implants for interventional closure of the LAA is likely to become a valuable alternative for stroke prevention, especially in patients with contraindication for oral anticoagulation as safety, clinical benefit and cost-effectiveness of LAA occlusion has recently been demonstrated.
