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
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
To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle＇s （AUV） motion controller, a six-degree of freedom （6-DOF） dynamic model for AUV controlled by thruster an...To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle＇s （AUV） motion controller, a six-degree of freedom （6-DOF） dynamic model for AUV controlled by thruster and fins with appendages is examined. Based on the dynamic model, a simulation system for the AUV＇s motion is established. The different kinds of typical motions are simulated to analyze the motion performance and the maneuverability of the AUV. In order to evaluate the influences of appendages on the motion performance of the AUV, simulations of the AUV with and without appendages are performed and compared. The results demonstrate the AUV has good maneuverability with and without appendages.展开更多
Nonlinear dynamics of liquid-filled rectangular tank with elastic appendages are studied. Based on the assumption of ideal fluid, the coupling dynamic equations of rigid tank, elastic appendages and liquid fuel are de...Nonlinear dynamics of liquid-filled rectangular tank with elastic appendages are studied. Based on the assumption of ideal fluid, the coupling dynamic equations of rigid tank, elastic appendages and liquid fuel are derived using H-O principle. In the case of pitch excitation, the modified potential function and wave height function are introduced to describe the moving boundary of fluid, then Galerkin＇s method is used to discretize the dynamic equations into ordinary differential equations. The natural frequencics of the coupling system are formulated in liquid depth, the length of the tank, etc. The formulae are confirmed by numerical simulations, which also show that the effects of liquid and elastic appendages on the attitude angular of rigid.展开更多
Circular RNAs （circRNAs） are endogenous non-coding RNAs that participate in regulating gene expression in diverse biological and pathological processes. The roles of circRNAs in atrial fibrillation （AF） have not b...Circular RNAs （circRNAs） are endogenous non-coding RNAs that participate in regulating gene expression in diverse biological and pathological processes. The roles of circRNAs in atrial fibrillation （AF） have not been well elucidated. In the present study, circRNAs profile in the atrial appendages of patients with AF was examined. Methods Hematoxylin-eosin （HE） and Masson trichrome staining was performed on the atrial appendages of patients with sinus rhythm （SR） or AF, Expressions of fibrosis, rennin-angiotensin-aldo- sterone system （RAAS） and inflammation-associated genes were determined by quantitative reverse transcrip- tion PCR （qRT-PCR）. CircRNAs expression profile in atrial appendages was detected by circ RNAs microarray. qRT-PCR was also used to determine the expression of 6 representative dys-regulated circRNAs. PCR products of concerned circRNAs were further identified by gel electrophoresis and DNA sequencing assay. Results Masson tricbrome staining result showed that fibrosis was increased in the atrial appendages of AF patients. The levels of collal, Col3al, fibrinectin-1 （FN1）, 1L1-β and CRP mRNA expression were significantly up-regulated in the atrial appendages of AF patients. A circRNAs array revealed that circRNAs were dysregulated in the atrial appendages of AF patients, qRT-PCR results demonstrated that circRNA 100395 was up-regulated, circRNA_ 101270, circRNA_103820, circRNA_104168 and circRNA_100782 were down-regulated significantly in the atri- al appendages of AF patients compared to SR patients. Conclusions Fibrosis and inflammation occur in the atrial appendages of AF patients, which could relate tocircRNAs dysregulation.展开更多
Mantodea(praying mantises)is a group of exclusively predatory insects,which,together with nonraptorial blattodeans(cockroaches and termites)and groups exclusively found in the fossil record,form the group Dictyoptera....Mantodea(praying mantises)is a group of exclusively predatory insects,which,together with nonraptorial blattodeans(cockroaches and termites)and groups exclusively found in the fossil record,form the group Dictyoptera.A central characteristic of Mantodea is the specialization of their first pair of legs as raptorial grasping appendages,but the evolution from walking to raptorial legs is not yet fully understood.Here,we trace the evolution of the raptorial appendages in Dictyoptera through time using a morphometric(morphospaces)approach.We also describe two new mantodean nymphs preserved in amber from the Cretaceous and Eocene,which expand the scarce mantodean fossil record.Blattodean and mantodean appendages appear distinct in morphospace,but several appendages of fossil non-mantodeans can be considered raptorial,providing a potential transitional link between walking and raptorial morphotypes.Therefore,we discuss potential mantodean affinities for other predatory fossil dictyopterans.We examine changes across extant mantodeans,characterized by a straightening of the tibia especially associated with the rise of the diversification of the Mantidea and discuss whether a thickening of the femur could reflect an early adaptation to cursorial hunting.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
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
BACKGROUND Epiploic appendagitis is a rare,often underrecognized cause of acute abdominal pain.Misdiagnosis can lead to unnecessary hospitalization,antibiotic use,or surgical intervention.Advances in imaging have impr...BACKGROUND Epiploic appendagitis is a rare,often underrecognized cause of acute abdominal pain.Misdiagnosis can lead to unnecessary hospitalization,antibiotic use,or surgical intervention.Advances in imaging have improved the recognition of this self-limiting condition,but clinical awareness remains critical.AIM To provide a comprehensive update on the epidemiology,anatomy,pathogenesis,clinical presentation,diagnostic strategies,differential diagnosis,and management of epiploic appendagitis,emphasizing its distinguishing features from other causes of acute abdomen.METHODS A review of the literature was conducted,focusing on the clinical characteristics,imaging findings,differential diagnoses,and evidence-based management strategies for epiploic appendagitis.RESULTS Epiploic appendagitis typically presents with acute,localized,non-radiating abdominal pain without significant systemic symptoms.Diagnosis is heavily reliant on imaging,with computed tomography(CT)being the gold standard.Hallmark CT findings include a small,fat-density ovoid lesion adjacent to the colon,with the usual characteristic ring and dot signs.Differential diagnoses include mainly diverticulitis,appendicitis,omental infarction,and many other causes.Management is predominantly conservative with nonsteroidal anti-inflammatory drugs and observation,reserving surgical intervention for rare,complicated cases.CONCLUSION Recognizing the clinical and imaging features of epiploic appendagitis is essential to avoid unnecessary interventions.Increased clinician awareness,coupled with judicious use of imaging,facilitates timely diagnosis and appropriate management,ensuring optimal patient outcomes.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
In this paper,we present an overview of numerical simulation methods for the flow around typical underwater vehicles at high Reynolds numbers,which highlights the dominant flow structures in different regions of inter...In this paper,we present an overview of numerical simulation methods for the flow around typical underwater vehicles at high Reynolds numbers,which highlights the dominant flow structures in different regions of interest.This overview covers the forebody,midbody,stern,wake region,and appendages and summarizes flow phenomena,including laminar-to-turbulent transition,turbulent boundary layers,flow under the influence of curvatures,wake interactions,and all associated complex vortex structures.Furthermore,the current issues and challenges of capturing these flow structures are addressed.This overview provides a deep insight into the use of numerical simulation methods,including the Reynolds-averaged Navier–Stokes(RANS)method,large eddy simulation(LES)method,and the hybrid RANS/LES method,and evaluates their applicability in capturing detailed flow features.展开更多
Signifcant advancements have been made in recent years in the development of highly sophisticated skin organoids.Serving as three-dimensional(3D)models that mimic human skin,these organoids have evolved into complex s...Signifcant advancements have been made in recent years in the development of highly sophisticated skin organoids.Serving as three-dimensional(3D)models that mimic human skin,these organoids have evolved into complex structures and are increasingly recognized as efective alternatives to traditional culture models and human skin due to their ability to overcome the limitations of two-dimensional(2D)systems and ethical concerns.The inherent plasticity of skin organoids allows for their construction into physiological and pathological models,enabling the study of skin development and dynamic changes.This review provides an overview of the pivotal work in the progression from 3D layered epidermis to cyst-like skin organoids with appendages.Furthermore,it highlights the latest advancements in organoid construction facilitated by state-of-the-art engineering techniques,such as 3D printing and microfuidic devices.The review also summarizes and discusses the diverse applications of skin organoids in developmental biology,disease modelling,regenerative medicine,and personalized medicine,while considering their prospects and limitations.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
The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy(CAA)and atrial fibrilla...The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy(CAA)and atrial fibrillation(AF).In fact,CAA is an age-related cerebral vasculopathy that predisposes patients to intracerebral hemorrhage.Nevertheless,many AF patients require oral systemic dose-adjusted warfarin,direct oral anticoagulants(such as factor Xa inhibitors)or direct thrombin inhibitors to control often associated with cardioembolic stroke risk.The prevalence of both CAA and AF is expected to rise,due to the aging of the population.This clinical dilemma is becoming increasingly common.In patients with coexisting AF and CAA,the risks/benefits profile of anticoagulant therapy must be assessed for each patient individually due to the lack of a clear-cut consensus with regard to its risks in scientific literature.This review aims to provide an overview of the management of patients with concomitant AF and CAA and proposes the implementation of a risk-based decision-making algorithm.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
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.
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.
基金Supported by the National Natural Science Foundation of China under Grant No.50909025
文摘To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle＇s （AUV） motion controller, a six-degree of freedom （6-DOF） dynamic model for AUV controlled by thruster and fins with appendages is examined. Based on the dynamic model, a simulation system for the AUV＇s motion is established. The different kinds of typical motions are simulated to analyze the motion performance and the maneuverability of the AUV. In order to evaluate the influences of appendages on the motion performance of the AUV, simulations of the AUV with and without appendages are performed and compared. The results demonstrate the AUV has good maneuverability with and without appendages.
基金Project supported by the National Natural Science Foundation of China (Nos. 10302013 and 10572022)
文摘Nonlinear dynamics of liquid-filled rectangular tank with elastic appendages are studied. Based on the assumption of ideal fluid, the coupling dynamic equations of rigid tank, elastic appendages and liquid fuel are derived using H-O principle. In the case of pitch excitation, the modified potential function and wave height function are introduced to describe the moving boundary of fluid, then Galerkin＇s method is used to discretize the dynamic equations into ordinary differential equations. The natural frequencics of the coupling system are formulated in liquid depth, the length of the tank, etc. The formulae are confirmed by numerical simulations, which also show that the effects of liquid and elastic appendages on the attitude angular of rigid.
基金supported by grants from the National Natural Science Foundation of China(No.81470439/81270222/81302779/81370295)Natural Science Foundation of Guangdong Province(No.2014A030313635/S2011020005911)
文摘Circular RNAs （circRNAs） are endogenous non-coding RNAs that participate in regulating gene expression in diverse biological and pathological processes. The roles of circRNAs in atrial fibrillation （AF） have not been well elucidated. In the present study, circRNAs profile in the atrial appendages of patients with AF was examined. Methods Hematoxylin-eosin （HE） and Masson trichrome staining was performed on the atrial appendages of patients with sinus rhythm （SR） or AF, Expressions of fibrosis, rennin-angiotensin-aldo- sterone system （RAAS） and inflammation-associated genes were determined by quantitative reverse transcrip- tion PCR （qRT-PCR）. CircRNAs expression profile in atrial appendages was detected by circ RNAs microarray. qRT-PCR was also used to determine the expression of 6 representative dys-regulated circRNAs. PCR products of concerned circRNAs were further identified by gel electrophoresis and DNA sequencing assay. Results Masson tricbrome staining result showed that fibrosis was increased in the atrial appendages of AF patients. The levels of collal, Col3al, fibrinectin-1 （FN1）, 1L1-β and CRP mRNA expression were significantly up-regulated in the atrial appendages of AF patients. A circRNAs array revealed that circRNAs were dysregulated in the atrial appendages of AF patients, qRT-PCR results demonstrated that circRNA 100395 was up-regulated, circRNA_ 101270, circRNA_103820, circRNA_104168 and circRNA_100782 were down-regulated significantly in the atri- al appendages of AF patients compared to SR patients. Conclusions Fibrosis and inflammation occur in the atrial appendages of AF patients, which could relate tocircRNAs dysregulation.
基金support in the frame of a Lichtenberg professorship and the German Research Foundation(DFG HA 6300/6-1)performed at the Imaging Center of the Department of Biology,University of Greifswald(DFG INST 292/119-1 FUGGDFG INST 292/120-1 FUGG).
文摘Mantodea(praying mantises)is a group of exclusively predatory insects,which,together with nonraptorial blattodeans(cockroaches and termites)and groups exclusively found in the fossil record,form the group Dictyoptera.A central characteristic of Mantodea is the specialization of their first pair of legs as raptorial grasping appendages,but the evolution from walking to raptorial legs is not yet fully understood.Here,we trace the evolution of the raptorial appendages in Dictyoptera through time using a morphometric(morphospaces)approach.We also describe two new mantodean nymphs preserved in amber from the Cretaceous and Eocene,which expand the scarce mantodean fossil record.Blattodean and mantodean appendages appear distinct in morphospace,but several appendages of fossil non-mantodeans can be considered raptorial,providing a potential transitional link between walking and raptorial morphotypes.Therefore,we discuss potential mantodean affinities for other predatory fossil dictyopterans.We examine changes across extant mantodeans,characterized by a straightening of the tibia especially associated with the rise of the diversification of the Mantidea and discuss whether a thickening of the femur could reflect an early adaptation to cursorial hunting.
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.
文摘BACKGROUND Epiploic appendagitis is a rare,often underrecognized cause of acute abdominal pain.Misdiagnosis can lead to unnecessary hospitalization,antibiotic use,or surgical intervention.Advances in imaging have improved the recognition of this self-limiting condition,but clinical awareness remains critical.AIM To provide a comprehensive update on the epidemiology,anatomy,pathogenesis,clinical presentation,diagnostic strategies,differential diagnosis,and management of epiploic appendagitis,emphasizing its distinguishing features from other causes of acute abdomen.METHODS A review of the literature was conducted,focusing on the clinical characteristics,imaging findings,differential diagnoses,and evidence-based management strategies for epiploic appendagitis.RESULTS Epiploic appendagitis typically presents with acute,localized,non-radiating abdominal pain without significant systemic symptoms.Diagnosis is heavily reliant on imaging,with computed tomography(CT)being the gold standard.Hallmark CT findings include a small,fat-density ovoid lesion adjacent to the colon,with the usual characteristic ring and dot signs.Differential diagnoses include mainly diverticulitis,appendicitis,omental infarction,and many other causes.Management is predominantly conservative with nonsteroidal anti-inflammatory drugs and observation,reserving surgical intervention for rare,complicated cases.CONCLUSION Recognizing the clinical and imaging features of epiploic appendagitis is essential to avoid unnecessary interventions.Increased clinician awareness,coupled with judicious use of imaging,facilitates timely diagnosis and appropriate management,ensuring optimal patient outcomes.
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.
基金Supported by the National Natural Science Foundation of China under Grant No.52131102.
文摘In this paper,we present an overview of numerical simulation methods for the flow around typical underwater vehicles at high Reynolds numbers,which highlights the dominant flow structures in different regions of interest.This overview covers the forebody,midbody,stern,wake region,and appendages and summarizes flow phenomena,including laminar-to-turbulent transition,turbulent boundary layers,flow under the influence of curvatures,wake interactions,and all associated complex vortex structures.Furthermore,the current issues and challenges of capturing these flow structures are addressed.This overview provides a deep insight into the use of numerical simulation methods,including the Reynolds-averaged Navier–Stokes(RANS)method,large eddy simulation(LES)method,and the hybrid RANS/LES method,and evaluates their applicability in capturing detailed flow features.
基金suppor ted by the National Key Research and Development Program of China(2022YFA1104800)the Beijing Nova Program(20220484100)+6 种基金the National Natural Science Foundation of China(81873939)the Open Research Fund of State Key Laboratory of Cardiovascular Disease,Fuwai Hospital(2022KF-04)the Clinical Medicine Plus X-Young Scholars Projec t,Pek ing Universit y(PKU2022LCXQ003)the Emerging Engineering InterdisciplinaryYoung Scholars Project,Peking University,the Fundamental Research Funds for the Central Universities(PKU2023XGK011)the Open Research Fund of State Key Laboratory of Digital Medical Engineering,Southeast University(2023K-01)the Open Research Fund of Beijing Key Laboratory of Metabolic Disorder Related Cardiovascular Disease,Beijing,China(DXWL2023-01)the Science and Technology Bureau Foundation Application Project of Changzhou(CJ20220118)。
文摘Signifcant advancements have been made in recent years in the development of highly sophisticated skin organoids.Serving as three-dimensional(3D)models that mimic human skin,these organoids have evolved into complex structures and are increasingly recognized as efective alternatives to traditional culture models and human skin due to their ability to overcome the limitations of two-dimensional(2D)systems and ethical concerns.The inherent plasticity of skin organoids allows for their construction into physiological and pathological models,enabling the study of skin development and dynamic changes.This review provides an overview of the pivotal work in the progression from 3D layered epidermis to cyst-like skin organoids with appendages.Furthermore,it highlights the latest advancements in organoid construction facilitated by state-of-the-art engineering techniques,such as 3D printing and microfuidic devices.The review also summarizes and discusses the diverse applications of skin organoids in developmental biology,disease modelling,regenerative medicine,and personalized medicine,while considering their prospects and limitations.
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.
文摘The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy(CAA)and atrial fibrillation(AF).In fact,CAA is an age-related cerebral vasculopathy that predisposes patients to intracerebral hemorrhage.Nevertheless,many AF patients require oral systemic dose-adjusted warfarin,direct oral anticoagulants(such as factor Xa inhibitors)or direct thrombin inhibitors to control often associated with cardioembolic stroke risk.The prevalence of both CAA and AF is expected to rise,due to the aging of the population.This clinical dilemma is becoming increasingly common.In patients with coexisting AF and CAA,the risks/benefits profile of anticoagulant therapy must be assessed for each patient individually due to the lack of a clear-cut consensus with regard to its risks in scientific literature.This review aims to provide an overview of the management of patients with concomitant AF and CAA and proposes the implementation of a risk-based decision-making algorithm.
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.
