Endocardial focal activation originating from Purkinje fibers plays a role in the maintenance of long duration ventricular fibrillation

Aim To determine the role of repetitive endocardial focal activations and Purkinje fibers in the maintenance of long duration ventricular fibrillation (LDVF, VF>1 minute) in canine hearts in vivo. Methods The study was conducted in electrophysiological laboratory of Shanghai Ruijin hospital from July 2010 to August 2012. A 64-electrode basket was introduced through a carotid artery into the left ventricle (LV) of 11 beagle dogs for global endocardial electrical mapping. In the Lugol’s solution group (n = 5), the subendocardium was ablated by washing with Lugol’s solution. In the control group, (n = 6) saline was used for ablation. Before and after saline or Lugol ablation, we determined QRS duration and QT/QTc interval in sinus rhythm (SR). We also measured the activation rates in the first 2 seconds of each minute during 7 minutes of VF for each group. If VF terminated spontaneously in less than 7 minutes, the VF segments used in activation rate analysis were reduced accordingly. Results At the beginning of VF there was no difference between the groups in the activation rate. However, after 1 minute of LDVF the Lugol’s solution group had significantly slower activation rate than the control group. In the control group, all episodes of LDVF (6/6) were successfully sustained for 7 minutes, while in the Lugol’s solution group 4/5 episodes of LDVF spontaneously terminated before 7 minutes (4.8 ± 1.4 minutes) (P = 0.015). In the control group, at 5.1 ± 1.3 minutes of LDVF, a successive, highly organized focal LV endocardial activation pattern was observed. During this period, activations partly arose in PF and spread to the working ventricular myocardium. Mapping analysis showed that these events were consistent with repetitive endocardial focal activations. No evidence of similar focal activations was observed in the Lugol’s solution group. Conclusions Repetitive endocardial focal activations in the LV endocardium may be associated with activation of subendocardial PFs. This mechanism may play an important role in the maintenance of LDVF

Optimization of molecular organization and nanoscale morphology for high performance low bandgap polymer solar cells

Air Force Office of Scientific Research [FA9550-13-1-0101]; National Science Foundation [ECCS-1305087]; Minjiang Scholar Program; Chinese Scholarship Council (CSC)Rational design and synthesis of low bandgap (LBG) polymers with judiciously tailored HOMO and LUMO levels have emerged as a viable route to high performance polymer solar cells with power conversion efficiencies (PCEs) exceeding 10%. In addition to engineering the energy-level of LBG polymers, the photovoltaic performance of LBG polymer-based solar cells also relies on the device architecture, in particular the fine morphology of the photoactive layer. The nanoscale interpenetrating networks composed of nanostructured donor and acceptor phases are the key to providing a large donor-acceptor interfacial area for maximizing the exciton dissociation and offering a continuous pathway for charge transport. In this Review Article, we summarize recent strategies for tuning the molecular organization and nanoscale morphology toward an enhanced photovoltaic performance of LBG polymer-based solar cells

High efficiency perovskite solar cells: from complex nanostructure to planar heterojunction

Air Force Office of Scientific Research [FA9550-13-1-0101]Perovskite solar cells have garnered great attention in recent years as promising high performance next-generation solar cells with long-term stability at low cost. Since the seminal work of Miyasaka and others in 2009, the power conversion efficiency (PCE) of perovskite-based dye-sensitized solar cells (DSSCs) has rapidly increased from 3.8% to 15% over the past four years, exceeding the highest efficiency of conventional organic dye-sensitized DSSCs. Recently, the perovskite has been demonstrated to act successfully as an active layer in simple planar-heterojunction solar cells with no need of complex nanostructured DSSC architectures, leading to an attractively high PCE of 15.4% at a competitive low manufacturing cost. In this Feature Article, we aim to review the recent impressive development in perovskite solar cells, and discuss the prognosis for future progress in exploiting perovskite materials for high efficiency solar cells

On root categories of finite-dimenisonal algebras

For any finite-dimensional algebra $A$ over a field $k$ with finite global dimension, we investigate the root category \cR_A as the triangulated hull of the 2-periodic orbit category of $A$ via the construction of B. Keller in "On triangulated orbit categories". This is motivated by Ringel-Hall Lie algebras associated to 2-periodic triangulated categories. As an application, we study the Ringel-Hall Lie algebras for a class of finite-dimensional $k$-algebras with global dimension 2, which turn out to give an alternative answer for a question of GIM Lie algebras by Slodowy in "Beyond Kac-Moody algebra, and inside".Comment: 25 page