Clinical efficacy of two different tricuspid annuloplasty techniques in left cardiac valve surgery

Objective: To investigate the mid-and long-term clinical effects of tricuspid valvuloplasty with the implantation of an artificial plastic ring.Methods: Data of 677 patients who had functional tricuspid regurgitation and left cardiac valve disease and underwent tricuspid valvuloplasty and left cardiac valve surgery were retrospectively.Among these patients, 353 underwent simple suture annuloplasty(group A) while the rest 324 patients underwent artificial plastic ring annuloplasty(group B).The two-year and more-than-two-year clinical and ultrasonocardiograph(UCG) follow-up data of the two groups were obtained and compared.Results: A total of 600 patients(88.6%) completed the long-term follow-up(more than two years).The two-year follow-up showed no significant difference in the incidence of mild tricuspid regurgitation between the two groups(82.2% vs.92.7%, P=0.37).However, there were significantly more cases that developed into moderate to severe tricuspid regurgitation in group A than in group B(17.8% vs.7.3%, P=0.031).The long-term follow-up revealed that the recurrence rate of tricuspid regurgitation in group B was significantly lower than that in group A(11.0% vs.25.0%, P=0.029), and the ratio of cases developing into moderate to severe tricuspid regurgitation in group A was significantly higher than that in group B(28.9% vs.9.9%, P=0.007).The comparison between the two intra-group time segments showed that the development of tricuspid regurgitation in group A was significantly increased(28.9% vs.17.8%, P=0.022), but in group B it was relatively stable(9.9% vs.7.3%, P=0.52).Conclusions: Artificial ring annuloplasty is associated with significantly less tricuspid regurgitation than simple suture annuloplasty.

The dynamics of traveling wavefronts for a model describing host tissue degradation by bacteria

In this paper,we mainly investigate the dynamics of traveling wavefronts for a model describing host tissue degradation by bacteria.We first establish the existence of spreading speed,and show that the spreading speed coincides with the minimal wave speed of traveling wavefronts.Moreover,a lower bound estimate of the spreading speed is given.Then,we prove that the traveling wavefronts with large speeds are globally exponentially stable,when the initial perturbation around the traveling wavefronts decays exponentially asχ→-∞,but the initial perturbation can be arbitrarily large in other locations.The adopted methods are the weighted energy and the squeezing technique.

Global stability of bistable traveling wavefronts for a three-species Lotka-Volterra competition system with nonlocal dispersal

This paper is devoted to the study of traveling wavefronts for a three-component Lotka-Volterra system with nonlocal dispersal.This system arises in the study of three-species competition model in which there is no competition between two of these three species.It has been shown that this system admits a bistable traveling wavefront.In this paper,we further investigate the stability of bistable traveling wavefronts.By constructing suitable super-and sub-solutions and using a dynamical system approach,we obtain the globally asymptotic stability of the bistable traveling wavefronts.

The minimal speed of traveling wave fronts for a three-cornponent competition system with nonlocal dispersal

In this paper,we study the linear determinacy of the minimal speed of traveling wave-fronts for a three-component competition system with nonlocal dispersal.We first trans-form this system into a cooperative system.Then,by constructing suitable upper solu-tions,we give some general conditions to ensure the linear determinacy of the minimalspeed.Finally,we provide some more precise conditions that only rely on the parametersof the system such that the linear determinacy of the minimal speed is assured.