Turbulent states and their transitions in mathematical models for ventricular tissue: The effects of random interstitial fibroblasts

We study the dynamical behaviors of two types of spiral-and scroll-wave turbulence states, respectively, in two-dimensional (2D) and three-dimensional (3D) mathematical models, of human, ventricular, myocyte cells that are attached to randomly distributed interstitial fibroblasts; these turbulence states are promoted by (a) the steep slope of the action-potential-duration-restitution (APDR) plot or (b) early afterdepolarizations (EADs). Our single-cell study shows that (1) the myocyte-fibroblast (MF) coupling G(j) and (2) the number N-f of fibroblasts in an MF unit lower the steepness of the APDR slope and eliminate the EAD behaviors of myocytes; we explore the pacing dependence of such EAD suppression. In our 2D simulations, we observe that a spiral-turbulence (ST) state evolves into a state with a single, rotating spiral (RS) if either (a) G(j) is large or (b) the maximum possible number of fibroblasts per myocyte N-f(max) is large. We also observe that the minimum value of G(j), for the transition from the ST to the RS state, decreases as N-f(max) increases. We find that, for the steep-APDR-induced ST state, once the MF coupling suppresses ST, the rotation period of a spiral in the RS state increases as (1) G(j) increases, with fixed N-f(max), and (2) N-f(max) increases, with fixed G(j). We obtain the boundary between ST and RS stability regions in the N-f(max)-G(j) plane. In particular, for low values of N-f(max), the value of G(j), at the ST-RS boundary, depends on the realization of the randomly distributed fibroblasts; this dependence decreases as N-f(max) increases. Our 3D studies show a similar transition from scroll-wave turbulence to a single, rotating, scroll-wave state because of the MF coupling. We examine the experimental implications of our study and propose that the suppression (a) of the steep slope of the APDR or (b) EADs can eliminate spiral-and scroll-wave turbulence in heterogeneous cardiac tissue, which has randomly distributed fibroblasts.

外生菌根真菌促进油松人工幼林生长的应用研究

从不同林型下分离获得的外生菌根真菌纯培养菌株中 ,选择了其中劣味乳菇、赫丝膜菌、褐环乳牛肝菌、毛边滑绣伞4株优良菌种 ,对油松人工幼林(5年生)进行菌剂混合接种试验。结果表明 :采用外生菌根真菌对油松幼林接菌 ,能够使土壤微生物种群数量发生变化 ;接菌后的土壤中的细菌、真菌、放线菌总数比不接菌的有明显的增加 ,其中真菌增加732.35 %。对接菌油松进行菌根侵染调查发现 ,接菌后的油松菌根侵染率为75 % ,不接菌的为20 % ;对连续两年接种菌剂的油松幼林调查发现 ,与不接菌剂的相比施用菌剂的油松地径、株高显著增加。由此认为 ,外生菌根真菌作为一项生物接种技术对促进油松幼林的生长具有重要作用

The consumer before the infoxication in the press discourse

In the media current context, the user is exposed every day to an informative saturation without precedents. The variety of the media by means of that it receives information, together with the revolution to all the levels that has supposed the Internet integration, it does that the consumer is bombarded literally by multitude of messages. But this bombardment does not imply an informative quality, but it can suppose an imbalance between the number of information and the quality of the same ones, avoiding so the user know the reality with veracity and depth. This article analyzes exhaustively the phenomenon of this overexposure named infoxication, the true dangers that it encloses, the possible solutions and how it affects the user and the Journalism in the production of written and audiovisual products through different mass media.

Anais.

2016