Image-based computational models have been used for vulnerable plaque progression and rupture predictions,and good results have been reported.However,mechanisms and predictions for plaque erosion are underinvestigated...Image-based computational models have been used for vulnerable plaque progression and rupture predictions,and good results have been reported.However,mechanisms and predictions for plaque erosion are underinvestigated.Patient-specific fluid-structure interaction(FSI)models based on optical coherence tomography(OCT)follow-up data from patients with plaque erosion and who received conservative antithrombotic treatment(using medication,no stenting)to identify risk factors that could be used to predict the treatment outcome.OCT and angiography datawere obtained from10 patientswho received conservative antithrombotic treatment.Five participants had worse outcomes(WOG,stenosis severity≥70%at one-year follow-up),while the other five had better outcomes(BOG,stenosis severity<70%at one-year follow-up).Patient-specific 3D FSI models were constructed to obtain morphological and biomechanical risk factor values(a total of nine risk factors)for comparison and prediction.A logistic regressionmodel was used to identify optimal predictors with the best treatment outcome prediction accuracies.Our results indicated that the combination of wall shear stress(WSS),lipid percent,and thrombus burden was the best group predictor according to the mean area under the curve(AUC)of 0.96(90%confidence interval=(0.85,1.00)).WSS was the best single predictor withmean AUC=0.70(90%confidence interval=(0.20,1.00)).Thrombus burden was the only risk factor showing statistically significant group difference,suggesting its crucial role in the outcomes of conservative anti-thrombotic therapy.This pilot study indicated that integratingmorphological and biomechanical risk factors could improve treatment outcome prediction accuracy in patients with plaque erosion compared to predictions using single predictors.Large-scale patient studies are needed to further validate our findings.展开更多
目的主动脉夹层疾病对主动脉血管壁各层的力学性质和微观结构的影响尚没有系统的研究。本文通过对比正常和发生A型夹层的人体升主动脉组织各层的力学性质和微观结构来探究该问题。方法从13例A型主动脉夹层患者和5例无主动脉疾病的供体...目的主动脉夹层疾病对主动脉血管壁各层的力学性质和微观结构的影响尚没有系统的研究。本文通过对比正常和发生A型夹层的人体升主动脉组织各层的力学性质和微观结构来探究该问题。方法从13例A型主动脉夹层患者和5例无主动脉疾病的供体中共采集了18个升主动脉标本。对每个升主动脉标本进一步分解以获得3个组织样本:主动脉壁全层、内膜-中膜层和外膜层。对每个组织样本进行双轴拉伸测试获得实验应力拉伸比数据,采用Fung-Type材料模型对实验数据进行拟合并计算组织硬度。采用Elastin Van Gieson染色和Masson染色来量化组织中弹性纤维和胶原纤维密度。采用统计分析以确定夹层主动脉和正常主动脉组织各层的力学和微观结构性质是否存在显著差异。结果在拉伸比为1.30时,夹层组内膜-中膜层样本的硬度在长轴方向上显著高于正常组(P=0.0068),而在其他方向或其他层组织中没有发现显著差异。尽管两组之间的弹性纤维或胶原纤维密度没有显著差异,但夹层组的所有3个组织层的弹性纤维密度通常较低,但胶原纤维密度较高。结论与正常主动脉组织相比,夹层主动脉组织中内膜-中膜层的弹性纤维密度较低,而组织硬度却较高,表明内膜-中膜层组织硬度可能是主动脉夹层的潜在生物标志物。展开更多
目的仅根据冠状动脉斑块形态难以有效识别具有破裂倾向并导致临床重大不良事件的易损斑块。斑块生物力学与斑块破裂密切相关。如何利用这些力学信息对斑块破裂程度进行评估仍是一项重大挑战。方法获取了40名冠心病患者的冠脉斑块在体光...目的仅根据冠状动脉斑块形态难以有效识别具有破裂倾向并导致临床重大不良事件的易损斑块。斑块生物力学与斑块破裂密切相关。如何利用这些力学信息对斑块破裂程度进行评估仍是一项重大挑战。方法获取了40名冠心病患者的冠脉斑块在体光学相干断层影像,并根据其斑块形态特征将斑块分为3组:20个稳定斑块、10个易损斑块和10个破裂斑块。对每个斑块进行有限元力学仿真,并提取斑块纤维帽和肩部区域的斑块应力峰值进行后续分析。基于斑块应力峰值提出斑块破裂风险的力学评估方案,从生物力学角度对3组斑块进行分组,并与形态学分组结果进行对比,计算两种分组的一致性。结果破裂和易损斑块的斑块应力峰值显著高于稳定斑块(P<0.0001和P=0.0007),而破裂和易损斑块之间没有发现显著差异(P=0.8538)。以150 k Pa和230 k Pa为斑块应力阈值建立了力学评估方案从而对斑块进行分组,对稳定斑块、易损斑块、破裂斑块的分组结果与形态学分组结果重合率分别为17/20、5/10和7/10。结论该斑块力学评估方案与形态学分组的高度一致性证明了其能有效评估冠脉斑块破裂风险的能力。特别对于稳定斑块,两种分组结果的高度一致表明结合斑块力学和形态可以可靠地识别仅具有稳定斑块的患者,以避免不必要的手术干预。展开更多
A mathematical model is designed to investigate Tuberculosis(TB)disease under the vaccination,treatment,andenvironmental impact with real cases.First,we introduce the model formulation in non-integer order derivativea...A mathematical model is designed to investigate Tuberculosis(TB)disease under the vaccination,treatment,andenvironmental impact with real cases.First,we introduce the model formulation in non-integer order derivativeand then,extend the model into fractional order derivative.The fractional system’s existence,uniqueness,andother relevant properties are shown.Then,we study the stability analysis of the equilibrium points.The disease-free equilibrium(DFE)D_(0)is locally asymptotically stable(LAS)when R_(v)<1.Further,we show the globalasymptotical stability(GAS)of the endemic equilibrium(EE)D*for R_(v)>1 and D_(0)for R_(v)≤1.The existenceof bifurcation analysis in the model is investigated,and it is shown the system possesses the forward bifurcationphenomenon.Sensitivity analysis has been performed to determine the sensitive parameters that impact R_(v).Weconsider the real TB statistics from Khyber Pakhtunkhwa in Pakistan and parameterized the model.The computedbasic reproduction number obtained using the real cases is R0≈3.6615.Various numerical results regardingdisease elimination of the sensitive parameters are shown graphically.展开更多
In this study, we prove the of existence of solutions of a convolution Volterra integral equation in the space of the Lebesgue integrable function on the set of positive real numbers and with the standard norm defined...In this study, we prove the of existence of solutions of a convolution Volterra integral equation in the space of the Lebesgue integrable function on the set of positive real numbers and with the standard norm defined on it. An operator P was assigned to the convolution integral operator which was later expressed in terms of the superposition operator and the nonlinear operator. Given a ball B<sub>r</sub> belonging to the space L it was established that the operator P maps the ball into itself. The Hausdorff measure of noncompactness was then applied by first proving that given a set M∈ B r the set is bounded, closed, convex and nondecreasing. Finally, the Darbo fixed point theorem was applied on the measure obtained from the set E belonging to M. From this application, it was observed that the conditions for the Darbo fixed point theorem was satisfied. This indicated the presence of at least a fixed point for the integral equation which thereby implying the existence of solutions for the integral equation.展开更多
Understanding cardiac blood flow behaviors is of importance for cardiovascular research and clinical assessment of ventricle functions.Patient-specific Echo-based left ventricle(LV)fluid-structure interaction(FSI)mode...Understanding cardiac blood flow behaviors is of importance for cardiovascular research and clinical assessment of ventricle functions.Patient-specific Echo-based left ventricle(LV)fluid-structure interaction(FSI)models were introduced to perform ventricle mechanical analysis,investigate flow behaviors,and evaluate the impact of myocardial infarction(MI)and hypertension on blood flow in the LV.Echo image data were acquired from 3 patients with consent obtained:one healthy volunteer(P1),one hypertension patient(P2),and one patient who had an inferior and posterior myocardial infarction(P3).The nonlinear Mooney-Rivlin model was used for ventricle tissue with material parameter values chosen to match echo-measure LV volume data.Using the healthy case as baseline,LV with MI had lower peak flow velocity(30%lower at beginejection)and hypertension LV had higher peak flow velocity(16%higher at begin-filling).The vortex area(defined as the area with vorticity>0)for P3 was 19%smaller than that of P1.The vortex area for P2 was 12%smaller than that of P1.At peak of filling,the maximum flow shear stress(FSS)for P2 and P3 were 390%higher and 63%lower than that of P1,respectively.Meanwhile,LV stress and strain of P2 were 41%and 15%higher than those of P1,respectively.LV stress and strain of P3 were 36%and 42%lower than those of P1,respectively.In conclusion,FSI models could provide both flow and structural stress/strain information which would serve as the base for further cardiovascular investigations related to disease initiation,progression,and treatment strategy selections.Large-scale studies are needed to validate our findings.展开更多
In this paper, we present a nonorthogonal overlapping Yee method for solv- ing Maxwell＇s equations using the diagonal split-cell model. When material interface is presented, the diagonal split-cell model does not req...In this paper, we present a nonorthogonal overlapping Yee method for solv- ing Maxwell＇s equations using the diagonal split-cell model. When material interface is presented, the diagonal split-cell model does not require permittivity averaging so that better accuracy can be achieved. Our numerical results on optical force computation show that the standard FDTD method converges linearly, while the proposed method achieves quadratic convergence and better accuracy.展开更多
Background:For over 40 years,the franchise ownership redirection hypothesis has attracted the attention of many scholars.This study,differing from previous ones,proposes an alternative approach for this hypothesis usi...Background:For over 40 years,the franchise ownership redirection hypothesis has attracted the attention of many scholars.This study,differing from previous ones,proposes an alternative approach for this hypothesis using a real options framework with the extension of agency theory.Method:The real options model is built using the least square Monte Carlo method,where the franchisor’s decision to franchise is perceived as a deferred investment while maintaining the right of future acquisition.Result:Tested using monte carlo simulation based hypothetical case,the model shows a different result from classical real options call model.This is mainly due to franchise contractual arrangement,where royalty fee lower the threshold of acquisition cost in converting the franchise outlet to company owned.Conclusion:The aim of this study is to create an analytical framework that helps a franchisor decide whether or not toacquire and convert a franchise unit to a company-owned unit at a certain point in time,analyzing the choice as a deferment of investment.The franchisors that faces the opportunity to optimize profit by converting the franchise unit to a company-owned unit should acknowledge it as real options thus negotiate the terms with their franchisees.展开更多
Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,en...Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,endothelium-absent and non-ruptured but often-inflamed plaques based on histological findings.Even though there is efficient imaging technologies to detect the eroded plaque in vivo and tailored treatment strategy has also been developed for ACScaused by erosion in clinics,the pathogenesis mechanisms that cause plaque erosion are not fully understood.It is widely postulated that thrombus formation and endothelial apoptosis(the precursors of plaque erosion)have closed association with biomechanical conditions in the coronary vessel.Revealing of the mechanical conditions in the eroded plaque could advance our knowledge in understanding the formation of plaque erosion.To this end,patient-specific OCT-based fluid-structure interaction(FSI)models were developed to investigate the plaque biomechanical conditions and investigate the impact of erosioninduced inflammation on biomechanical conditions.In vivo OCTand Biplane X-ray angiographic data of eroded coronary plaque were acquired from one male patient(age:64). OCT images were segmented manually with external elastic membrane contour and the trailing edge of the lipid-rich necrotic core(lipid)assumed to have positive remodeling ratio 1.1.Locations with luminal surface having direct contact with intraluminal thrombus on OCT images were identified erosion sites.Fusion of OCT and biplane X-ray angiographic data were performed to obtain the 3D coronary geometry.OCT-based FSI models with pre-shrink-stretch process and anisotropic material properties were constructed following previously established procedures.To reflect tissue weakening caused by erosion-induced inflammation,the material stiffness of plaque intima at the erosion site was adjust to one tenth of un-eroded fibrous plaque tissue.Three FSI models were constructed to investigate the impacts of inflammation and lipid component on plaque biomechanics:M1,without erosion(this means plaque intima at the erosion sites were not softened)and without inclusion of lipid component;M2,with erosion but no lipid;M3,with erosion and inclusion of lipid.FSI models were solved by ADINA to obtain the biomechanical conditions at peak blood pressure including plaque wall stress/strain(PWS/PWSn)and flow wall shear stress(WSS).The average values of three biomechanical conditions at the erosion sites and at the fibrous cap overlaying lipid component were calculated from three models for analysis.The results of M1 and M2 were compared to investigate the impact of erosion-induced inflammation on plaque biomechanics.Mean PWS value decreases from 49.98 kPa to 18.83 kPa(62.32%decrease)while Mean PWSn value increases from 0.123 1 to 0.138 4(12%increase)as the material stiffness becomes 10times soft.Comparing M2 and M3 at the cap sites,M3(with inclusion of lipid)will elevates mean PWS and PWSn values by48.59%and 16.09%,respectively.The impacts of erosion and lipid on flow shear stress were limited(<2%).To conclude,erosion-induced inflammation would lead to lower stress distribution but larger strain distribution,while lipid would elevate both stress and strain conditions.This shows the influence of erosion and lipid component has impacts on stress/strain cal-culations which are closely related to plaque assessment.展开更多
The selection of predictors plays a crucial role in building a multiple regression model. Indeed, the choice of a suitable subset of predictors can help to improve prediction accuracy and interpretation. In this paper...The selection of predictors plays a crucial role in building a multiple regression model. Indeed, the choice of a suitable subset of predictors can help to improve prediction accuracy and interpretation. In this paper, we propose a flexible Bayesian Lasso and adaptive Lasso quantile regression by introducing a hierarchical model framework approach to enable exact inference and shrinkage of an unimportant coefficient to zero. The error distribution is assumed to be an infinite mixture of Gaussian densities. We have theoretically investigated and numerically compared our proposed methods with Flexible Bayesian quantile regression (FBQR), Lasso quantile regression (LQR) and quantile regression (QR) methods. Simulations and real data studies are conducted under different settings to assess the performance of the proposed methods. The proposed methods perform well in comparison to the other methods in terms of median mean squared error, mean and variance of the absolute correlation criterions. We believe that the proposed methods are useful practically.展开更多
In this paper,we study the shock waves for a mixed-type system from chemotaxis.We are concerned with the jump conditions for the left state which is located in the elliptical region and the right state in the hyperbol...In this paper,we study the shock waves for a mixed-type system from chemotaxis.We are concerned with the jump conditions for the left state which is located in the elliptical region and the right state in the hyperbolic region.Under the generalized entropy conditions,we find that there are different shock wave structures for different parameters.To guarantee the uniqueness of the solutions,we obtain the admissible shock waves which satisfy the generalized entropy condition in both parameters.Finally,we construct the Riemann solutions in some solvable regions.展开更多
Aortic valve replacement(AVR)remains a major treatment option for patients with severe aortic valve disease.Clinical outcome of AVR is strongly dependent on implanted prosthetic valve size.Fluid-structure interaction(...Aortic valve replacement(AVR)remains a major treatment option for patients with severe aortic valve disease.Clinical outcome of AVR is strongly dependent on implanted prosthetic valve size.Fluid-structure interaction(FSI)aortic root models were constructed to investigate the effect of valve size on hemodynamics of the implanted bioprosthetic valve and optimize the outcome of AVR surgery.FSI models with 4 sizes of bioprosthetic valves(19(No.19),21(No.21),23(No.23)and 25 mm(No.25))were constructed.Left ventricle outflow track flow data from one patient was collected and used as model flow conditions.Anisotropic Mooney–Rivlin models were used to describe mechanical properties of aortic valve leaflets.Blood flow pressure,velocity,systolic valve orifice pressure gradient(SVOPG),systolic cross-valve pressure difference(SCVPD),geometric orifice area,and flow shear stresses from the four valve models were compared.Our results indicated that larger valves led to lower transvalvular pressure gradient,which is linked to better post AVR outcome.Peak SVOPG,mean SCVPD and maximum velocity for Valve No.25 were 48.17%,49.3%,and 44.60%lower than that from Valve No.19,respectively.Geometric orifice area from Valve No.25 was 52.03%higher than that from Valve No.19(1.87 cm2 vs.1.23 cm2).Implantation of larger valves can significantly reduce mean flow shear stress on valve leaflets.Our initial results suggested that larger valve size may lead to improved hemodynamic performance and valve cardiac function post AVR.More patient studies are needed to validate our findings.展开更多
In this study, boundary control problems with Neumann conditions for 2 × 2 cooperative hyperbolic systems involving infinite order operators are considered. The existence and uniqueness of the states of these sys...In this study, boundary control problems with Neumann conditions for 2 × 2 cooperative hyperbolic systems involving infinite order operators are considered. The existence and uniqueness of the states of these systems are proved, and the formulation of the control problem for different observation functions is discussed.展开更多
Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in patients with tetralogy of Fallot(TOF).Congenital bicuspid pulmonary valve(BPV)is a condition of valvular stenosis,and ...Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in patients with tetralogy of Fallot(TOF).Congenital bicuspid pulmonary valve(BPV)is a condition of valvular stenosis,and the occurrence of congenital BPV is often associated with TOF.Dynamic computational models of normal pulmonary root(PR)with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions.The pulmonary root geometry included valvular leaflets,sinuses,interleaflet triangles and annulus.Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing of human PV leaflet,and characterized by an anisotropic Mooney-Rivlin model.The complete cardiac cycle was simulated to observe valve leaflet dynamic stress/strain behaviors.Our results indicated that stress/strain distribution patterns of normal tri-leaflet pulmonary valve(TPV)and the BPV were different on valve leaflets when the valve was fully open,but they were similar when valves were completely closed.When the valve was fully open,the BPV maximum stress value on the leaflets was 197.2 kPa,which was 94.3%higher than of the normal TPV value(101.5 kPa).During the valve was fully open,the stress distribution in the interleaflet triangles region of the PR was asymmetric in the BPV model compared with that in the TPV model.The geometric orifice area value in the completely opened position of BPV model was reduced 55.6%from that of the normal PV.Our initial results demonstrated that valve geometrical variations with BPV may be a potential risk factor linked to occurrence of PVS in patients with TOF.Computational models could be a useful tool in identifying possible linkage between valve disease development and biomechanical factors.Large-scale clinical studies are needed to validate these preliminary findings.展开更多
Many agricultural fields across the country have a high degree of variability in soil type and water holding capacity that affects irrigation management. One way to overcome problems associated with the field variabil...Many agricultural fields across the country have a high degree of variability in soil type and water holding capacity that affects irrigation management. One way to overcome problems associated with the field variability for improving irrigation management is to utilize a site-specific irrigation system. This system applies water to match the needs of individual management zones within a field. A real-time continuous soil moisture measurement is essential for the success of site-specific irrigation systems. Recently the National Aeronautics and Space Administration (NASA) developed sensor technology that records the global positioning system (GPS) signal reflected from the surface of Earth, which estimates the dielectric properties of soil and can be used to estimate soil moisture contents. The overall objective of this study was to determine the feasibility of utilizing GPS-based technology developed by NASA for soil moisture measurements and to determine the influence of soil type, soil compaction, and ground cover on the measurements. The results showed strong positive correlations between soil moisture and reflected signals. Other factors (soil compaction and soil type), were not significantly related to reflectivity and did not significantly change the relationship between reflectivity and soil moisture contents. In addition, ground cover (rye crop) did not significantly reduce reflectivity. Therefore, this system could be used as a real-time and continuous nonintrusive soil moisture sensor for site-specific irrigation scheduling and watershed management.展开更多
Non-local plane elasticity problems are discussed in the context of Λ-fractional linear elasticity theory. Adapting the Λ-fractional derivative along with the Λ-fractional space, where geometry and mechanics are va...Non-local plane elasticity problems are discussed in the context of Λ-fractional linear elasticity theory. Adapting the Λ-fractional derivative along with the Λ-fractional space, where geometry and mechanics are valid in the conventional way, non-local plane elasticity problems are solved with the help of biharmonic functions. Then, the results are transferred into the initial plane.Applications are presented to homogeneous and the fractional beam bending problem.展开更多
Homogenous and heterogeneous production of hydrogen via photo-dissociation of water has been achieved with visible range solar radiation without any external potential at room temperature. Potassium ferrocyanide as a ...Homogenous and heterogeneous production of hydrogen via photo-dissociation of water has been achieved with visible range solar radiation without any external potential at room temperature. Potassium ferrocyanide as a solvated-electron supplier and electron exchanger in basic buffers was used as a homogenous media for hydrogen production. Aqueous colloidal solutions of p-type Fe2O3 doped with MgO （Fe1.8Mg0.2O3） or with ZnO （Fe1.9Zn0.1O3） suspensions in ferrocyanide solutions were used as heterogeneous media for hydrogen generation by reduction of ferricyanide. The effects of the hole-scavengers such as oxo-anions and solvated-electron- suppliers were investigated. Results showed that Fe2O3 doped with ZnO was more efficient than that doped with MgO. The studies also showed that the aqueous nano-systems we used retained their stability as indicated by the reproducibility of their photocatalytic activities. Solar radiated assemblies of doped Fe2O3/[Fe（CN）6]4^- sustained cyclic systems for continuous hydrogen production.展开更多
First-principle calculations are performed to study geometric and electronic properties of both neutral and anionic In4M and In12M （M = C, Si, In） clusters. In4C and In4Si are found to be tetrahedral molecules. The ...First-principle calculations are performed to study geometric and electronic properties of both neutral and anionic In4M and In12M （M = C, Si, In） clusters. In4C and In4Si are found to be tetrahedral molecules. The icosahedral structure is found to be unfavourable for In12M. The most stable structure for In12C is a distorted buckled biplanar structure while for In12Si it is of an In-cage with the Si located in the centre. Charge effect on the structure of In12M is discussed. In4C has a significantly large binding energy and an energy gap between the highest-occupied molecularorbital level and the lowest unoccupied molecular-orbital level, a low electron affinity, and a high ionization potential, which are the characters of a magic cluster, enriching the family of doped-group-IIIA metal clusters for cluster-assembled materials.展开更多
Objective Patients with repaired tetralogy of Fallot(rTOF)account for the majority of cases with late onset right ventricle(RV)failure.The current surgical approach,including pulmonary valve replacement/insertion(PVR)...Objective Patients with repaired tetralogy of Fallot(rTOF)account for the majority of cases with late onset right ventricle(RV)failure.The current surgical approach,including pulmonary valve replacement/insertion(PVR),has yielded mixed results with some patients recover RV function and some do not.An innovative surgical approach was proposed to help ventricle to contract and improve RV function qualified by ejection fraction with one or more active contracting bands.Computational biomechanical modelling is a widely used method in cardiovascular study for investigation of mechanisms governing disease development,quantitative diagnostic and treatment strategies and improving surgical designs for better outcome.Muscle active contraction caused by zero-load sarcomere shortening leads to change of zero-load configurations.In lieu of experimenting using real surgery on animal or human,computational simulations(virtual surgery)were performed to test different band combination and insertion options to identify optimal surgery design and band insertion plan.Methods Cardiac magnetic resonance(CMR)data were obtained from one rTOF patient(sex:male,age:22.5 y)before pulmonary valve replacement surgery.The patient was suffering from RV dilation and dysfunction with RV end-systole volume 254.49ml and end-diastole volume 406.91 mL.A total of 15 computational RV/LV/Patch/Band combination models based on(CMR)imaging were constructed to investigate the influence of different band insertion surgery plans.These models included 5 different band insertion models combined and 3 different band contraction ratio(10%,15%and 20%band zero-stress length reduction).These models included 5 different band insertion models:Model 1 with one band at anterior to the middle of papillary muscle;Model 2 with one band at posterior to the middle of papillary muscle;Model 3 with 2 bands which are the ones from Models 1&2 combined;Model 4 with a band at the base of the papillary muscle;Model 5 with 3 bands which is a combination of Models 3&4.A pre-shrink process was performed on in-vivo begin-filling and end-systole MRI data to obtain diastole and systole zero4oad ventricle geometries.An extra 5%-8%shrinkage was applied to obtain corresponding systole zero-load geometry reflecting myocardium sarcomere shortening.The zero-load band length in systole was 10%,15%and 20%shorter than that in diastole according to their corresponding contraction ratio.The nonlinear Mooney-Rivlin model was used to describe the ventricle material properties with their material parameter values adjusted to match measured data with CMR.The band material properties were in the same scale with healthy right ventricle.The RV/LV/Band model construction and solution procedures were the same as described.Results Model 5 with band contraction ratio of 20%has the ability to improve RV ejection fraction to 41.07%,which represented a 3.61%absolute improvement,or 9.6%relative improvement using pre-PVR ejection fraction as the baseline number.The ejection fractions for Models 1-4 with band contraction ratio of 20%were 39.28%,39.47%,38.87%and 40.34%respectively.Compared to models with band contraction ratio15%and 20%,models with band contraction ratio 10%has the least ability on RV ejection fraction improvement with ejection fraction 38.28%,38.00%,38.81%,38.50%and 39.36%corresponding to Models 1-5.Conclusions This pilot work demonstrated that the band insertion surgery may have great potential to improve post-PVR RV cardiac function for patients with repaired TOF.More band contraction ratio and inserted band number may lead to better post-surgery outcome.Further investigations using in-vitro animal experiments and final patient studies are warranted.展开更多
By using the multiple-scale method, this paper analytically studies the effect of a barrier potential on the dynamical characteristics of the soliton in Bose Einstein eondensates. It is shown that a stable soliton is ...By using the multiple-scale method, this paper analytically studies the effect of a barrier potential on the dynamical characteristics of the soliton in Bose Einstein eondensates. It is shown that a stable soliton is exhibited at the top of the barrier potential and the region of the absence of the barrier potential. Meanwhile, it is found that the height of the barrier potential has an important effect on the dark soliton dynamical characteristics in the condensates. With the increase of height of the barrier potential, the amplitude of the dark soliton becomes smaller, its width is narrower, and the soliton propagates more slowly.展开更多
基金supported in part by National Sciences Foundation of China grants 11972117a Jiangsu Province Science and Technology Agency under grant number BE2016785+4 种基金support from Natural Science Foundation of China(81827806 and 62135002)support from Natural Science Foundation of China(81722025)Key R&D Project of Heilongjiang Province grant 2022ZX06C07support from the Natural Science Foundation of Shandong Province under grant number ZR2024QA110Shandong Province Medical Health Science and Technology Project(Nos.202425020256,and 202403010254).
文摘Image-based computational models have been used for vulnerable plaque progression and rupture predictions,and good results have been reported.However,mechanisms and predictions for plaque erosion are underinvestigated.Patient-specific fluid-structure interaction(FSI)models based on optical coherence tomography(OCT)follow-up data from patients with plaque erosion and who received conservative antithrombotic treatment(using medication,no stenting)to identify risk factors that could be used to predict the treatment outcome.OCT and angiography datawere obtained from10 patientswho received conservative antithrombotic treatment.Five participants had worse outcomes(WOG,stenosis severity≥70%at one-year follow-up),while the other five had better outcomes(BOG,stenosis severity<70%at one-year follow-up).Patient-specific 3D FSI models were constructed to obtain morphological and biomechanical risk factor values(a total of nine risk factors)for comparison and prediction.A logistic regressionmodel was used to identify optimal predictors with the best treatment outcome prediction accuracies.Our results indicated that the combination of wall shear stress(WSS),lipid percent,and thrombus burden was the best group predictor according to the mean area under the curve(AUC)of 0.96(90%confidence interval=(0.85,1.00)).WSS was the best single predictor withmean AUC=0.70(90%confidence interval=(0.20,1.00)).Thrombus burden was the only risk factor showing statistically significant group difference,suggesting its crucial role in the outcomes of conservative anti-thrombotic therapy.This pilot study indicated that integratingmorphological and biomechanical risk factors could improve treatment outcome prediction accuracy in patients with plaque erosion compared to predictions using single predictors.Large-scale patient studies are needed to further validate our findings.
文摘目的主动脉夹层疾病对主动脉血管壁各层的力学性质和微观结构的影响尚没有系统的研究。本文通过对比正常和发生A型夹层的人体升主动脉组织各层的力学性质和微观结构来探究该问题。方法从13例A型主动脉夹层患者和5例无主动脉疾病的供体中共采集了18个升主动脉标本。对每个升主动脉标本进一步分解以获得3个组织样本:主动脉壁全层、内膜-中膜层和外膜层。对每个组织样本进行双轴拉伸测试获得实验应力拉伸比数据,采用Fung-Type材料模型对实验数据进行拟合并计算组织硬度。采用Elastin Van Gieson染色和Masson染色来量化组织中弹性纤维和胶原纤维密度。采用统计分析以确定夹层主动脉和正常主动脉组织各层的力学和微观结构性质是否存在显著差异。结果在拉伸比为1.30时,夹层组内膜-中膜层样本的硬度在长轴方向上显著高于正常组(P=0.0068),而在其他方向或其他层组织中没有发现显著差异。尽管两组之间的弹性纤维或胶原纤维密度没有显著差异,但夹层组的所有3个组织层的弹性纤维密度通常较低,但胶原纤维密度较高。结论与正常主动脉组织相比,夹层主动脉组织中内膜-中膜层的弹性纤维密度较低,而组织硬度却较高,表明内膜-中膜层组织硬度可能是主动脉夹层的潜在生物标志物。
文摘目的仅根据冠状动脉斑块形态难以有效识别具有破裂倾向并导致临床重大不良事件的易损斑块。斑块生物力学与斑块破裂密切相关。如何利用这些力学信息对斑块破裂程度进行评估仍是一项重大挑战。方法获取了40名冠心病患者的冠脉斑块在体光学相干断层影像,并根据其斑块形态特征将斑块分为3组:20个稳定斑块、10个易损斑块和10个破裂斑块。对每个斑块进行有限元力学仿真,并提取斑块纤维帽和肩部区域的斑块应力峰值进行后续分析。基于斑块应力峰值提出斑块破裂风险的力学评估方案,从生物力学角度对3组斑块进行分组,并与形态学分组结果进行对比,计算两种分组的一致性。结果破裂和易损斑块的斑块应力峰值显著高于稳定斑块(P<0.0001和P=0.0007),而破裂和易损斑块之间没有发现显著差异(P=0.8538)。以150 k Pa和230 k Pa为斑块应力阈值建立了力学评估方案从而对斑块进行分组,对稳定斑块、易损斑块、破裂斑块的分组结果与形态学分组结果重合率分别为17/20、5/10和7/10。结论该斑块力学评估方案与形态学分组的高度一致性证明了其能有效评估冠脉斑块破裂风险的能力。特别对于稳定斑块,两种分组结果的高度一致表明结合斑块力学和形态可以可靠地识别仅具有稳定斑块的患者,以避免不必要的手术干预。
基金supporting this work through the Large Research Group Project under Grant No.R.G.P.2/507/45.
文摘A mathematical model is designed to investigate Tuberculosis(TB)disease under the vaccination,treatment,andenvironmental impact with real cases.First,we introduce the model formulation in non-integer order derivativeand then,extend the model into fractional order derivative.The fractional system’s existence,uniqueness,andother relevant properties are shown.Then,we study the stability analysis of the equilibrium points.The disease-free equilibrium(DFE)D_(0)is locally asymptotically stable(LAS)when R_(v)<1.Further,we show the globalasymptotical stability(GAS)of the endemic equilibrium(EE)D*for R_(v)>1 and D_(0)for R_(v)≤1.The existenceof bifurcation analysis in the model is investigated,and it is shown the system possesses the forward bifurcationphenomenon.Sensitivity analysis has been performed to determine the sensitive parameters that impact R_(v).Weconsider the real TB statistics from Khyber Pakhtunkhwa in Pakistan and parameterized the model.The computedbasic reproduction number obtained using the real cases is R0≈3.6615.Various numerical results regardingdisease elimination of the sensitive parameters are shown graphically.
文摘In this study, we prove the of existence of solutions of a convolution Volterra integral equation in the space of the Lebesgue integrable function on the set of positive real numbers and with the standard norm defined on it. An operator P was assigned to the convolution integral operator which was later expressed in terms of the superposition operator and the nonlinear operator. Given a ball B<sub>r</sub> belonging to the space L it was established that the operator P maps the ball into itself. The Hausdorff measure of noncompactness was then applied by first proving that given a set M∈ B r the set is bounded, closed, convex and nondecreasing. Finally, the Darbo fixed point theorem was applied on the measure obtained from the set E belonging to M. From this application, it was observed that the conditions for the Darbo fixed point theorem was satisfied. This indicated the presence of at least a fixed point for the integral equation which thereby implying the existence of solutions for the integral equation.
文摘Understanding cardiac blood flow behaviors is of importance for cardiovascular research and clinical assessment of ventricle functions.Patient-specific Echo-based left ventricle(LV)fluid-structure interaction(FSI)models were introduced to perform ventricle mechanical analysis,investigate flow behaviors,and evaluate the impact of myocardial infarction(MI)and hypertension on blood flow in the LV.Echo image data were acquired from 3 patients with consent obtained:one healthy volunteer(P1),one hypertension patient(P2),and one patient who had an inferior and posterior myocardial infarction(P3).The nonlinear Mooney-Rivlin model was used for ventricle tissue with material parameter values chosen to match echo-measure LV volume data.Using the healthy case as baseline,LV with MI had lower peak flow velocity(30%lower at beginejection)and hypertension LV had higher peak flow velocity(16%higher at begin-filling).The vortex area(defined as the area with vorticity>0)for P3 was 19%smaller than that of P1.The vortex area for P2 was 12%smaller than that of P1.At peak of filling,the maximum flow shear stress(FSS)for P2 and P3 were 390%higher and 63%lower than that of P1,respectively.Meanwhile,LV stress and strain of P2 were 41%and 15%higher than those of P1,respectively.LV stress and strain of P3 were 36%and 42%lower than those of P1,respectively.In conclusion,FSI models could provide both flow and structural stress/strain information which would serve as the base for further cardiovascular investigations related to disease initiation,progression,and treatment strategy selections.Large-scale studies are needed to validate our findings.
基金supported by the Air Force Office of Scientific Research (AFOSR) under Grant numbers FA9550-04-1-0213 and FA9550-07-1-0010
文摘In this paper, we present a nonorthogonal overlapping Yee method for solv- ing Maxwell＇s equations using the diagonal split-cell model. When material interface is presented, the diagonal split-cell model does not require permittivity averaging so that better accuracy can be achieved. Our numerical results on optical force computation show that the standard FDTD method converges linearly, while the proposed method achieves quadratic convergence and better accuracy.
文摘Background:For over 40 years,the franchise ownership redirection hypothesis has attracted the attention of many scholars.This study,differing from previous ones,proposes an alternative approach for this hypothesis using a real options framework with the extension of agency theory.Method:The real options model is built using the least square Monte Carlo method,where the franchisor’s decision to franchise is perceived as a deferred investment while maintaining the right of future acquisition.Result:Tested using monte carlo simulation based hypothetical case,the model shows a different result from classical real options call model.This is mainly due to franchise contractual arrangement,where royalty fee lower the threshold of acquisition cost in converting the franchise outlet to company owned.Conclusion:The aim of this study is to create an analytical framework that helps a franchisor decide whether or not toacquire and convert a franchise unit to a company-owned unit at a certain point in time,analyzing the choice as a deferment of investment.The franchisors that faces the opportunity to optimize profit by converting the franchise unit to a company-owned unit should acknowledge it as real options thus negotiate the terms with their franchisees.
基金supported in part by NSFC ( 11672001,11802060)Jiangsu NSF ( BK20180352)Jiangsu Province Science and Technology Agency ( BE2016785)
文摘Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,endothelium-absent and non-ruptured but often-inflamed plaques based on histological findings.Even though there is efficient imaging technologies to detect the eroded plaque in vivo and tailored treatment strategy has also been developed for ACScaused by erosion in clinics,the pathogenesis mechanisms that cause plaque erosion are not fully understood.It is widely postulated that thrombus formation and endothelial apoptosis(the precursors of plaque erosion)have closed association with biomechanical conditions in the coronary vessel.Revealing of the mechanical conditions in the eroded plaque could advance our knowledge in understanding the formation of plaque erosion.To this end,patient-specific OCT-based fluid-structure interaction(FSI)models were developed to investigate the plaque biomechanical conditions and investigate the impact of erosioninduced inflammation on biomechanical conditions.In vivo OCTand Biplane X-ray angiographic data of eroded coronary plaque were acquired from one male patient(age:64). OCT images were segmented manually with external elastic membrane contour and the trailing edge of the lipid-rich necrotic core(lipid)assumed to have positive remodeling ratio 1.1.Locations with luminal surface having direct contact with intraluminal thrombus on OCT images were identified erosion sites.Fusion of OCT and biplane X-ray angiographic data were performed to obtain the 3D coronary geometry.OCT-based FSI models with pre-shrink-stretch process and anisotropic material properties were constructed following previously established procedures.To reflect tissue weakening caused by erosion-induced inflammation,the material stiffness of plaque intima at the erosion site was adjust to one tenth of un-eroded fibrous plaque tissue.Three FSI models were constructed to investigate the impacts of inflammation and lipid component on plaque biomechanics:M1,without erosion(this means plaque intima at the erosion sites were not softened)and without inclusion of lipid component;M2,with erosion but no lipid;M3,with erosion and inclusion of lipid.FSI models were solved by ADINA to obtain the biomechanical conditions at peak blood pressure including plaque wall stress/strain(PWS/PWSn)and flow wall shear stress(WSS).The average values of three biomechanical conditions at the erosion sites and at the fibrous cap overlaying lipid component were calculated from three models for analysis.The results of M1 and M2 were compared to investigate the impact of erosion-induced inflammation on plaque biomechanics.Mean PWS value decreases from 49.98 kPa to 18.83 kPa(62.32%decrease)while Mean PWSn value increases from 0.123 1 to 0.138 4(12%increase)as the material stiffness becomes 10times soft.Comparing M2 and M3 at the cap sites,M3(with inclusion of lipid)will elevates mean PWS and PWSn values by48.59%and 16.09%,respectively.The impacts of erosion and lipid on flow shear stress were limited(<2%).To conclude,erosion-induced inflammation would lead to lower stress distribution but larger strain distribution,while lipid would elevate both stress and strain conditions.This shows the influence of erosion and lipid component has impacts on stress/strain cal-culations which are closely related to plaque assessment.
文摘The selection of predictors plays a crucial role in building a multiple regression model. Indeed, the choice of a suitable subset of predictors can help to improve prediction accuracy and interpretation. In this paper, we propose a flexible Bayesian Lasso and adaptive Lasso quantile regression by introducing a hierarchical model framework approach to enable exact inference and shrinkage of an unimportant coefficient to zero. The error distribution is assumed to be an infinite mixture of Gaussian densities. We have theoretically investigated and numerically compared our proposed methods with Flexible Bayesian quantile regression (FBQR), Lasso quantile regression (LQR) and quantile regression (QR) methods. Simulations and real data studies are conducted under different settings to assess the performance of the proposed methods. The proposed methods perform well in comparison to the other methods in terms of median mean squared error, mean and variance of the absolute correlation criterions. We believe that the proposed methods are useful practically.
基金the National Natural Science Foundation of China(11771442)。
文摘In this paper,we study the shock waves for a mixed-type system from chemotaxis.We are concerned with the jump conditions for the left state which is located in the elliptical region and the right state in the hyperbolic region.Under the generalized entropy conditions,we find that there are different shock wave structures for different parameters.To guarantee the uniqueness of the solutions,we obtain the admissible shock waves which satisfy the generalized entropy condition in both parameters.Finally,we construct the Riemann solutions in some solvable regions.
基金The research was supported in part by National Sciences Foundation of China Grants 11672001,81571691 and 81771844.
文摘Aortic valve replacement(AVR)remains a major treatment option for patients with severe aortic valve disease.Clinical outcome of AVR is strongly dependent on implanted prosthetic valve size.Fluid-structure interaction(FSI)aortic root models were constructed to investigate the effect of valve size on hemodynamics of the implanted bioprosthetic valve and optimize the outcome of AVR surgery.FSI models with 4 sizes of bioprosthetic valves(19(No.19),21(No.21),23(No.23)and 25 mm(No.25))were constructed.Left ventricle outflow track flow data from one patient was collected and used as model flow conditions.Anisotropic Mooney–Rivlin models were used to describe mechanical properties of aortic valve leaflets.Blood flow pressure,velocity,systolic valve orifice pressure gradient(SVOPG),systolic cross-valve pressure difference(SCVPD),geometric orifice area,and flow shear stresses from the four valve models were compared.Our results indicated that larger valves led to lower transvalvular pressure gradient,which is linked to better post AVR outcome.Peak SVOPG,mean SCVPD and maximum velocity for Valve No.25 were 48.17%,49.3%,and 44.60%lower than that from Valve No.19,respectively.Geometric orifice area from Valve No.25 was 52.03%higher than that from Valve No.19(1.87 cm2 vs.1.23 cm2).Implantation of larger valves can significantly reduce mean flow shear stress on valve leaflets.Our initial results suggested that larger valve size may lead to improved hemodynamic performance and valve cardiac function post AVR.More patient studies are needed to validate our findings.
文摘In this study, boundary control problems with Neumann conditions for 2 × 2 cooperative hyperbolic systems involving infinite order operators are considered. The existence and uniqueness of the states of these systems are proved, and the formulation of the control problem for different observation functions is discussed.
文摘Pulmonary valve stenosis(PVS)is one common right ventricular outflow tract obstruction problem in patients with tetralogy of Fallot(TOF).Congenital bicuspid pulmonary valve(BPV)is a condition of valvular stenosis,and the occurrence of congenital BPV is often associated with TOF.Dynamic computational models of normal pulmonary root(PR)with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions.The pulmonary root geometry included valvular leaflets,sinuses,interleaflet triangles and annulus.Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing of human PV leaflet,and characterized by an anisotropic Mooney-Rivlin model.The complete cardiac cycle was simulated to observe valve leaflet dynamic stress/strain behaviors.Our results indicated that stress/strain distribution patterns of normal tri-leaflet pulmonary valve(TPV)and the BPV were different on valve leaflets when the valve was fully open,but they were similar when valves were completely closed.When the valve was fully open,the BPV maximum stress value on the leaflets was 197.2 kPa,which was 94.3%higher than of the normal TPV value(101.5 kPa).During the valve was fully open,the stress distribution in the interleaflet triangles region of the PR was asymmetric in the BPV model compared with that in the TPV model.The geometric orifice area value in the completely opened position of BPV model was reduced 55.6%from that of the normal PV.Our initial results demonstrated that valve geometrical variations with BPV may be a potential risk factor linked to occurrence of PVS in patients with TOF.Computational models could be a useful tool in identifying possible linkage between valve disease development and biomechanical factors.Large-scale clinical studies are needed to validate these preliminary findings.
文摘Many agricultural fields across the country have a high degree of variability in soil type and water holding capacity that affects irrigation management. One way to overcome problems associated with the field variability for improving irrigation management is to utilize a site-specific irrigation system. This system applies water to match the needs of individual management zones within a field. A real-time continuous soil moisture measurement is essential for the success of site-specific irrigation systems. Recently the National Aeronautics and Space Administration (NASA) developed sensor technology that records the global positioning system (GPS) signal reflected from the surface of Earth, which estimates the dielectric properties of soil and can be used to estimate soil moisture contents. The overall objective of this study was to determine the feasibility of utilizing GPS-based technology developed by NASA for soil moisture measurements and to determine the influence of soil type, soil compaction, and ground cover on the measurements. The results showed strong positive correlations between soil moisture and reflected signals. Other factors (soil compaction and soil type), were not significantly related to reflectivity and did not significantly change the relationship between reflectivity and soil moisture contents. In addition, ground cover (rye crop) did not significantly reduce reflectivity. Therefore, this system could be used as a real-time and continuous nonintrusive soil moisture sensor for site-specific irrigation scheduling and watershed management.
文摘Non-local plane elasticity problems are discussed in the context of Λ-fractional linear elasticity theory. Adapting the Λ-fractional derivative along with the Λ-fractional space, where geometry and mechanics are valid in the conventional way, non-local plane elasticity problems are solved with the help of biharmonic functions. Then, the results are transferred into the initial plane.Applications are presented to homogeneous and the fractional beam bending problem.
基金supported by Indiana University Sum-mer Faculty Fellowship Program
文摘Homogenous and heterogeneous production of hydrogen via photo-dissociation of water has been achieved with visible range solar radiation without any external potential at room temperature. Potassium ferrocyanide as a solvated-electron supplier and electron exchanger in basic buffers was used as a homogenous media for hydrogen production. Aqueous colloidal solutions of p-type Fe2O3 doped with MgO （Fe1.8Mg0.2O3） or with ZnO （Fe1.9Zn0.1O3） suspensions in ferrocyanide solutions were used as heterogeneous media for hydrogen generation by reduction of ferricyanide. The effects of the hole-scavengers such as oxo-anions and solvated-electron- suppliers were investigated. Results showed that Fe2O3 doped with ZnO was more efficient than that doped with MgO. The studies also showed that the aqueous nano-systems we used retained their stability as indicated by the reproducibility of their photocatalytic activities. Solar radiated assemblies of doped Fe2O3/[Fe（CN）6]4^- sustained cyclic systems for continuous hydrogen production.
文摘First-principle calculations are performed to study geometric and electronic properties of both neutral and anionic In4M and In12M （M = C, Si, In） clusters. In4C and In4Si are found to be tetrahedral molecules. The icosahedral structure is found to be unfavourable for In12M. The most stable structure for In12C is a distorted buckled biplanar structure while for In12Si it is of an In-cage with the Si located in the centre. Charge effect on the structure of In12M is discussed. In4C has a significantly large binding energy and an energy gap between the highest-occupied molecularorbital level and the lowest unoccupied molecular-orbital level, a low electron affinity, and a high ionization potential, which are the characters of a magic cluster, enriching the family of doped-group-IIIA metal clusters for cluster-assembled materials.
基金supported in part by National Sciences Foundation of China grants ( 11672001, 81571691,81771844)
文摘Objective Patients with repaired tetralogy of Fallot(rTOF)account for the majority of cases with late onset right ventricle(RV)failure.The current surgical approach,including pulmonary valve replacement/insertion(PVR),has yielded mixed results with some patients recover RV function and some do not.An innovative surgical approach was proposed to help ventricle to contract and improve RV function qualified by ejection fraction with one or more active contracting bands.Computational biomechanical modelling is a widely used method in cardiovascular study for investigation of mechanisms governing disease development,quantitative diagnostic and treatment strategies and improving surgical designs for better outcome.Muscle active contraction caused by zero-load sarcomere shortening leads to change of zero-load configurations.In lieu of experimenting using real surgery on animal or human,computational simulations(virtual surgery)were performed to test different band combination and insertion options to identify optimal surgery design and band insertion plan.Methods Cardiac magnetic resonance(CMR)data were obtained from one rTOF patient(sex:male,age:22.5 y)before pulmonary valve replacement surgery.The patient was suffering from RV dilation and dysfunction with RV end-systole volume 254.49ml and end-diastole volume 406.91 mL.A total of 15 computational RV/LV/Patch/Band combination models based on(CMR)imaging were constructed to investigate the influence of different band insertion surgery plans.These models included 5 different band insertion models combined and 3 different band contraction ratio(10%,15%and 20%band zero-stress length reduction).These models included 5 different band insertion models:Model 1 with one band at anterior to the middle of papillary muscle;Model 2 with one band at posterior to the middle of papillary muscle;Model 3 with 2 bands which are the ones from Models 1&2 combined;Model 4 with a band at the base of the papillary muscle;Model 5 with 3 bands which is a combination of Models 3&4.A pre-shrink process was performed on in-vivo begin-filling and end-systole MRI data to obtain diastole and systole zero4oad ventricle geometries.An extra 5%-8%shrinkage was applied to obtain corresponding systole zero-load geometry reflecting myocardium sarcomere shortening.The zero-load band length in systole was 10%,15%and 20%shorter than that in diastole according to their corresponding contraction ratio.The nonlinear Mooney-Rivlin model was used to describe the ventricle material properties with their material parameter values adjusted to match measured data with CMR.The band material properties were in the same scale with healthy right ventricle.The RV/LV/Band model construction and solution procedures were the same as described.Results Model 5 with band contraction ratio of 20%has the ability to improve RV ejection fraction to 41.07%,which represented a 3.61%absolute improvement,or 9.6%relative improvement using pre-PVR ejection fraction as the baseline number.The ejection fractions for Models 1-4 with band contraction ratio of 20%were 39.28%,39.47%,38.87%and 40.34%respectively.Compared to models with band contraction ratio15%and 20%,models with band contraction ratio 10%has the least ability on RV ejection fraction improvement with ejection fraction 38.28%,38.00%,38.81%,38.50%and 39.36%corresponding to Models 1-5.Conclusions This pilot work demonstrated that the band insertion surgery may have great potential to improve post-PVR RV cardiac function for patients with repaired TOF.More band contraction ratio and inserted band number may lead to better post-surgery outcome.Further investigations using in-vitro animal experiments and final patient studies are warranted.
文摘By using the multiple-scale method, this paper analytically studies the effect of a barrier potential on the dynamical characteristics of the soliton in Bose Einstein eondensates. It is shown that a stable soliton is exhibited at the top of the barrier potential and the region of the absence of the barrier potential. Meanwhile, it is found that the height of the barrier potential has an important effect on the dark soliton dynamical characteristics in the condensates. With the increase of height of the barrier potential, the amplitude of the dark soliton becomes smaller, its width is narrower, and the soliton propagates more slowly.
