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
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
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
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 marine engineering,appendages such as fin stabilizers and/or T-foils are made to rotate and to reduce the motion of ships.Research on the hydrodynamics of ships fitted with active appendages has significantly impro...In marine engineering,appendages such as fin stabilizers and/or T-foils are made to rotate and to reduce the motion of ships.Research on the hydrodynamics of ships fitted with active appendages has significantly improved the design and control of such ships.However,most studies focus on fixed rather than rotating appendages,thereby ignoring the hydrodynamic unsteadiness of active appendages.To enhance the reliability and precision of the numerical simulations,we propose the use of overlapping grids for simulating advanced catamarans fitted with a pair of rotating T-foils under each bow.The fundamental purpose of the overlapping grid technique is to realize information exchange via regional overlap sharing in each subdomain of the computing domain,instead of using the method of boundary sharing,thus greatly alleviating the difficulty of generating the subdomain grid;moreover,the technique guarantees the quality of the subdomain grid.Within the main computational domain,a subdomain was allocated to accommodate the T-foil.Overlapping meshes near the interface between the two domains enable information flow during the simulation;the overlapping grids are updated at every iteration step because the subdomain rotates.The instantaneous trim and sinkage responses of the catamaran to the T-foil rotation were reproduced.From the moment the active T-foil stopped moving,there was no change in the ship’s sailing attitude,indicating that the response was in real time.By comparing with EFD data,the numerical results showed reasonable agreement,indicating the feasibility and effectiveness of the technique in simulating the hydrodynamics of ships fitted with active appendages.展开更多
A maternally inherited 828 kb microdeletion of 2q37.3 manifested in a 3-week-old premature boy as left juxtaposition of the atrial appendages associated with tricuspid atresia,double outlet infundibulum,subvalvar pulm...A maternally inherited 828 kb microdeletion of 2q37.3 manifested in a 3-week-old premature boy as left juxtaposition of the atrial appendages associated with tricuspid atresia,double outlet infundibulum,subvalvar pulmonary atresia,large secundum atrial septal defect,and right aortic arch with mirror-image branching,consistent with developmental arrest early in heart looping.To the best of our knowledge,no previous 2q37 deletion syndrome has been reported with such a severe cardiac dysmorphology.Hence,this case adds to the cardiac phenotypes identified in 2q37 deletion syndrome.展开更多
In order to establish the evolutionary relationships and resolve the polyphyletic nature of Dothideomycetes,we are studying their natural classification based on both morphology and multigene phylogeny.In this paper w...In order to establish the evolutionary relationships and resolve the polyphyletic nature of Dothideomycetes,we are studying their natural classification based on both morphology and multigene phylogeny.In this paper we introduce Vaginatispora appendiculata,a novel species on dead twigs from southern Thailand.Morphological character differences and analyses of combined LSU,TEF,SSU and ITS sequence datasets support the validity of the new species and its placement in Vaginatispora(Lophiostomataceae).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
Aims:Evidence is emerging that,in the setting of isomerism,the atrial and bronchial arrangement are not always concordant,nor are these patterns always harmonious with the arrangement of the abdominal organs.We aimed ...Aims:Evidence is emerging that,in the setting of isomerism,the atrial and bronchial arrangement are not always concordant,nor are these patterns always harmonious with the arrangement of the abdominal organs.We aimed to evaluate the concordance between these features in a cohort of patients with cardiac malformations in the setting of known isomerism,seeking to determine whether it was feasible to assess complexity on this basis,in this regard taking note of the potential value of bronchial as opposed to appendage morphology.Methods and Results:We studied 78 patients known to have isomerism of the bronchuses,43 with right and 35 with left isomerism.Appendage anatomy could be determined in 49 cases(63%),all but one of these being concordant with bronchial anatomy.When assessing abdominal features,in only 59 cases(76%)was splenic morphology in keeping with the thoracic findings.As expected,right isomerism was associated with greater complexity of cardiac malformations,with an odds ratio of 6.53,with confidence intervals from 2.2–19.3(p<0.001).The odds were slightly decreased with thoraco-abdominal disharmony,when lesions shown to carry higher risk were then found in the setting of left isomerism.Conclusion:Harmony is excellent between bronchial and appendage isomerism,but less so with the arrangement of the abdominal organs.Right isomerism in our cohort,was indicative of a sixfold increase in intracardiac complexity.When discordance was found between the systems,however,the cardiac anomalies were less typical of the anticipated findings for right vs.left isomerism of the appendages.展开更多
In the last issue,two case reports separately present examples of the extremely rare and complex congenital heart diseases that show concordant atrioventricular connections to the L-looped ventricles in the presence o...In the last issue,two case reports separately present examples of the extremely rare and complex congenital heart diseases that show concordant atrioventricular connections to the L-looped ventricles in the presence of situs solitus.Both cases highlight that the relationship between the two ventricles within the ventricular mass is not always harmonious with the given atrioventricular connection.Such disharmony between the connections and relationships requires careful assessment of the three basic facets of cardiac building blocks,namely their morphology,the relationship of their component parts,and their connections with the adjacent segments.3D imaging and printing can now facilitate an otherwise difficult diagnosis in such complex situations.Rotation of either the 3D images or the models permit accurate assessment of the ventricular topologic pattern by creating the right ventricular en-face septal view,thus facilitating placement of the observer’s hands.As we now emphasize,an alternative approach,which might prove more attractive to imagers,is to rotate the ventricular mass to provide the ventricular apical view,thus permitting determination of the ventricular relationship without using the hands.展开更多
Comparative morphological study of five varieties of Colocasia esculenta (L.) Schott present in Anambra State, Nigeria was carried out, in order to furnish plant taxonomists with information which could be of great he...Comparative morphological study of five varieties of Colocasia esculenta (L.) Schott present in Anambra State, Nigeria was carried out, in order to furnish plant taxonomists with information which could be of great help in delimitation of the varieties. Significant difference was established at p < 0.05. The result showed that adaxial surface of “kochuo” had a purplish dot on the centre, abaxial leaf surface had a conspicuous purplish colour at the point of attachment to the leaf, and the cormels had numerous striking vertical purple stripes on the surface. There was presence of foliaceous (leaf-like) appendages at the veins of the abaxial surface of the leaf of “ogeriobosi”. The leaf length ranged from 35.6 ± 7.70 cm (“kochuo”) to 49.9 ± 3.55 cm (“ogeriobosi”). Petiole length of “ogeriobosi” was the highest (63.3 ± 3.83 cm), whereas the least was Colocasia esculenta var. antiquorum (26.67 ± 2.20 cm). The corm length ranged from 4.10 ± 0.10 cm (Colocasia esculenta var. antiquorum) to 8.60 ± 0.35 cm (“ogeriobosi”), while the cormel length ranged from 3.70 ± 0.96 cm (Colocasia esculenta var. antiquorum) to 7.03 ± 0.36 cm (“ogeriobosi”). This work has revealed diagnostic and differential morphological characters, which could be useful for identification and description of varieties of C. esculenta. In addition, it provided additional information which might be helpful in resolving the on-going controversy in the taxonomy of Colocasia, which would, in turn, probably lead to possible delimitation of C. esculenta.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 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(Grant No.51509053)
文摘In marine engineering,appendages such as fin stabilizers and/or T-foils are made to rotate and to reduce the motion of ships.Research on the hydrodynamics of ships fitted with active appendages has significantly improved the design and control of such ships.However,most studies focus on fixed rather than rotating appendages,thereby ignoring the hydrodynamic unsteadiness of active appendages.To enhance the reliability and precision of the numerical simulations,we propose the use of overlapping grids for simulating advanced catamarans fitted with a pair of rotating T-foils under each bow.The fundamental purpose of the overlapping grid technique is to realize information exchange via regional overlap sharing in each subdomain of the computing domain,instead of using the method of boundary sharing,thus greatly alleviating the difficulty of generating the subdomain grid;moreover,the technique guarantees the quality of the subdomain grid.Within the main computational domain,a subdomain was allocated to accommodate the T-foil.Overlapping meshes near the interface between the two domains enable information flow during the simulation;the overlapping grids are updated at every iteration step because the subdomain rotates.The instantaneous trim and sinkage responses of the catamaran to the T-foil rotation were reproduced.From the moment the active T-foil stopped moving,there was no change in the ship’s sailing attitude,indicating that the response was in real time.By comparing with EFD data,the numerical results showed reasonable agreement,indicating the feasibility and effectiveness of the technique in simulating the hydrodynamics of ships fitted with active appendages.
文摘A maternally inherited 828 kb microdeletion of 2q37.3 manifested in a 3-week-old premature boy as left juxtaposition of the atrial appendages associated with tricuspid atresia,double outlet infundibulum,subvalvar pulmonary atresia,large secundum atrial septal defect,and right aortic arch with mirror-image branching,consistent with developmental arrest early in heart looping.To the best of our knowledge,no previous 2q37 deletion syndrome has been reported with such a severe cardiac dysmorphology.Hence,this case adds to the cardiac phenotypes identified in 2q37 deletion syndrome.
基金supported by the International Research Group Program(IRG-14-27)。
文摘In order to establish the evolutionary relationships and resolve the polyphyletic nature of Dothideomycetes,we are studying their natural classification based on both morphology and multigene phylogeny.In this paper we introduce Vaginatispora appendiculata,a novel species on dead twigs from southern Thailand.Morphological character differences and analyses of combined LSU,TEF,SSU and ITS sequence datasets support the validity of the new species and its placement in Vaginatispora(Lophiostomataceae).
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.
文摘Aims:Evidence is emerging that,in the setting of isomerism,the atrial and bronchial arrangement are not always concordant,nor are these patterns always harmonious with the arrangement of the abdominal organs.We aimed to evaluate the concordance between these features in a cohort of patients with cardiac malformations in the setting of known isomerism,seeking to determine whether it was feasible to assess complexity on this basis,in this regard taking note of the potential value of bronchial as opposed to appendage morphology.Methods and Results:We studied 78 patients known to have isomerism of the bronchuses,43 with right and 35 with left isomerism.Appendage anatomy could be determined in 49 cases(63%),all but one of these being concordant with bronchial anatomy.When assessing abdominal features,in only 59 cases(76%)was splenic morphology in keeping with the thoracic findings.As expected,right isomerism was associated with greater complexity of cardiac malformations,with an odds ratio of 6.53,with confidence intervals from 2.2–19.3(p<0.001).The odds were slightly decreased with thoraco-abdominal disharmony,when lesions shown to carry higher risk were then found in the setting of left isomerism.Conclusion:Harmony is excellent between bronchial and appendage isomerism,but less so with the arrangement of the abdominal organs.Right isomerism in our cohort,was indicative of a sixfold increase in intracardiac complexity.When discordance was found between the systems,however,the cardiac anomalies were less typical of the anticipated findings for right vs.left isomerism of the appendages.
文摘In the last issue,two case reports separately present examples of the extremely rare and complex congenital heart diseases that show concordant atrioventricular connections to the L-looped ventricles in the presence of situs solitus.Both cases highlight that the relationship between the two ventricles within the ventricular mass is not always harmonious with the given atrioventricular connection.Such disharmony between the connections and relationships requires careful assessment of the three basic facets of cardiac building blocks,namely their morphology,the relationship of their component parts,and their connections with the adjacent segments.3D imaging and printing can now facilitate an otherwise difficult diagnosis in such complex situations.Rotation of either the 3D images or the models permit accurate assessment of the ventricular topologic pattern by creating the right ventricular en-face septal view,thus facilitating placement of the observer’s hands.As we now emphasize,an alternative approach,which might prove more attractive to imagers,is to rotate the ventricular mass to provide the ventricular apical view,thus permitting determination of the ventricular relationship without using the hands.
文摘Comparative morphological study of five varieties of Colocasia esculenta (L.) Schott present in Anambra State, Nigeria was carried out, in order to furnish plant taxonomists with information which could be of great help in delimitation of the varieties. Significant difference was established at p < 0.05. The result showed that adaxial surface of “kochuo” had a purplish dot on the centre, abaxial leaf surface had a conspicuous purplish colour at the point of attachment to the leaf, and the cormels had numerous striking vertical purple stripes on the surface. There was presence of foliaceous (leaf-like) appendages at the veins of the abaxial surface of the leaf of “ogeriobosi”. The leaf length ranged from 35.6 ± 7.70 cm (“kochuo”) to 49.9 ± 3.55 cm (“ogeriobosi”). Petiole length of “ogeriobosi” was the highest (63.3 ± 3.83 cm), whereas the least was Colocasia esculenta var. antiquorum (26.67 ± 2.20 cm). The corm length ranged from 4.10 ± 0.10 cm (Colocasia esculenta var. antiquorum) to 8.60 ± 0.35 cm (“ogeriobosi”), while the cormel length ranged from 3.70 ± 0.96 cm (Colocasia esculenta var. antiquorum) to 7.03 ± 0.36 cm (“ogeriobosi”). This work has revealed diagnostic and differential morphological characters, which could be useful for identification and description of varieties of C. esculenta. In addition, it provided additional information which might be helpful in resolving the on-going controversy in the taxonomy of Colocasia, which would, in turn, probably lead to possible delimitation of C. esculenta.
