Emergence of a thread-like pattern with charged phospholipids on an oil∕water interface.

The spontaneous formation of a thread-like pattern with negatively charged lipids on an oil∕water interface is reported. An analysis of the time-dependent change at the interface observed by fluorescence microscopy revealed that the thread-like pattern is generated through a two-step mechanism. First, inverted lipid micelles in the bulk-oil phase gradually diffuse onto the oil∕water interface. Next, the micelles are adsorbed on the interface and self-assemble to form the thread-like pattern. The essential characteristics of this pattern formation are theoretically reproduced by a simple Monte Carlo simulation that takes into account the kinetics in the coalescence of charged micelles on a 2D interface

Computational Verification of So-Called Perovskite Solar Cells as PbI_6^<4−> -Aligned Solar Cells

Effective sensitizing components in so-called perovskite solar cells (PSC) are lead hexaiodide (PbI_6^) salts of PbI_6^ (MeNH_3^+)n (n = 2∼4). Density-functional-theory-based molecular modeling (DFT/MM) of X-ray crystalline structure of PbI_6^/MeNH_3^+ salt (FOLLIB) verifies that the packing unit of FOLLIB has UV/Vis absorption spectrum at λmax = 424 nm, giving pale yellow color as complementary color. DFT/MM of the horizontal component in the FOLLIB gives narrow energy gap of 0.3 eV, verifying remarkable semiconducting property through tight alignments of PbI_6^ components coupled with MeNH_3^+. DFT/MM of the central PbI_6^/MeNH_3^+ components verifies that the central component has UV/Vis absorption spectra with respective λmax = 570 nm, λmax = 762 nm and λmax = 945 nm, and plays an essential role as panchromatic sensitizers. In addition, their equilibrium geometric structures show slightly hypsochromic UV/Vis absorption spectra at respective λmax = 486 nm, λmax = 560 nm, and λmax = 563 nm as results of migration of MeNH_3^+ close to PbI_6^. DFT/MM also verifies that PbI_6^ components align tightly to nanocrystalline TiO_2 (nc-TiO_2) and to spiro-OMeTAD in PSC through electron density induced by van der Waals interaction. Electron density-based alignments of PbI_6^ components well explain unidirectional and leakage-free electron diffusion leading to high open-circuit voltage in PbI_6^-aligned solar cells. At the same time, the semiconducting and panchromatic sensitizing layer of PbI_6^/MeNH_3^+ components contribute to excellent short-circuit photocurrent of PbI_6^-aligned solar cells

Mechanisms of torsades de pointes: an update

Torsades de Pointes (TdP) refers to a polymorphic ventricular tachycardia (VT) with undulating QRS axis that occurs in long QT syndrome (LQTS), although the term has been used to describe polymorphic ventricular tachyarrhythmias in which QT intervals are not prolonged, such as short-coupled variant of TdP currently known as short-coupled ventricular fibrillation (VF) and Brugada syndrome. Extensive works on LQTS-related TdP over more than 50 years since it was first recognized by Dessertennes who coined the French term meaning “twisting of the points”, have led to current understanding of the electrophysiological mechanism that TdP is initiated by triggered activity due to early afterdepolarization (EAD) and maintained by reentry within a substrate of inhomogeneous repolarization. While a recently emerging notion that steep voltage gradients rather than EADs are crucial to generate premature ventricular contractions provides additions to the initiation mode, the research to elucidate the maintenance mechanism hasn't made much progress. The reentrant activity that produces the specific form of VT is not well characterized. We have conducted optical mapping in a rabbit model of electrical storm by electrical remodeling (QT prolongation) due to chronic complete atrioventricular block and demonstrated that a tissue-island with prolonged refractoriness due to enhanced late Na+ current (INa−L) contributes to the generation of drifting rotors in a unique manner, which may explain the ECG characteristic of TdP. Moreover, we have proposed that the neural Na+ channel NaV1.8-mediated INa−L may be a new player to form the substrate for TdP. Here we discuss TdP mechanisms by comparing the findings in electrical storm rabbits with recently published studies by others in simulation models and human and animal models of LQTS

Incidence, Mortality, and Predictive Factors of Hepatocellular Carcinoma in Primary Biliary Cirrhosis

Background. The study aims to analyze in detail the incidence, mortality using the standardized incidence ratio (SIR), and standardized mortality ratio (SMR) of hepatocellular carcinoma (HCC) in primary biliary cirrhosis (PBC), because no large case studies have focused on the detailed statistical analysis of them in Asia. Methods. The study cohorts were consecutively diagnosed at Gunma University and its affiliated hospitals. Age- or sex-specific annual cancer incidence and deaths were obtained from Japanese Cancer Registry and Death Registry as a reference for the comparison of SIR or SMR of HCC. Moreover, univariate analyses and multivariate analyses were performed to clarify predictive factors for the incidence of HCC. Results. The overall 179 patients were followed up for a median of 97 months. HCC had developed in 13 cases. SIR for HCC was 11.6 (95% confidence interval (CI), 6.2–19.8) and SMR for HCC was 11.2 (95% CI, 5.4–20.6) in overall patients. The serum albumin levels were a predictive factor for the incidence of HCC in overall patients. Conclusions. The incidence and mortality of HCC in PBC patients were significantly higher than those in Japanese general population. PBC patients with low serum albumin levels were populations at high risk for HCC