Critical behavior and magnetocaloric effect in Tsai-type 2/1 and 1/1 quasicrystal approximants

Stable Tsai-type quinary 1/1 and 2/1 approximant crystals (ACs) with chemical compositions Au56.25Al10Cu7In13Tb13.75 and Au55.5Al10Cu7In13Tb14.5, respectively, exhibiting ferromagnetic (FM) long-range orders were successfully synthesized and studied for their magnetic properties and magnetocaloric effect. The 1/1 and 2/1 ACs primarily differ in their long-range atomic arrangement and rare earth (RE) distribution, with the latter approaching quasiperiodic order while still preserving periodicity. Analyses based on the scaling principle and Kouvel-Fisher (KF) relations suggested mean-field-like behavior near Curie temperatures in both compounds. From magnetization measurements and the Maxwell equation, a magnetic entropy change of -4.3 and -4.1 J/K mol Tb were derived under a magnetic field change of 7 T for the 1/1 and 2/1 ACs, respectively. The results indicated a prominent role of intra-cluster magnetic interactions on critical behavior and magnetic entropy of the Tsai-type compounds

Direct calculation of mutual diffusion coefficients of binary system using non-equilibrium molecular dynamics simulation

Molecular dynamics (MD) simulation is widely used to calculate transport properties of fluids. In this study, non-equilibrium molecular dynamics (NEMD) simulation was applied to calculate mutual diffusion coefficients from the molecular flux at a given concentration gradient. First, the applicability of spherical molecular model was investigated by calculating self- and tracer diffusion coefficients of methane and n-decane mixture by a equilibrium MD simulation. The simulated self- and tracer diffusion coefficients of both components were in good agreement with literature data except in the case that methane molar fraction was nearly equal to zero. Further, the NEMD simulation was adopted to calculate mutual diffusion coefficients of binary system of methane and n-decane. This binary system exhibits anomalous concentration dependence of mutual diffusion coefficients in the vicinity of critical molar fraction according to the previously reported experimental data. The NEMD simulation well reproduced such concentration dependence of mutual diffusion coefficients. The simulation also gave a fairly good agreement with the calculated results by the Darken equation using tracer diffusion coefficients with a thermodynamic factor. © 2015 Elsevier B.V.Embargo Period 12 month

Changes in body composition parameters with age

Health risks are associated with changes in body composition parameters with age. In the present study, body composition parameters （appendicular skeletal muscle mass ［ASMM］, fat mass ［FM］, and water content ［water］） using bioelectrical impedance analysis （BIA） and total skeletal MM （TSMM） measured by 24-h creatinine excretion （Cr） were obtained in 30 male and 38 female healthy subjects. BIA-ASMM in both sexes and Cr-TSMM in females were negatively correlated with aging, and BIA-FM was negatively correlated with BIA-water in both sexes. Of note, Cr-TSMM was a more sensitive marker of MM than BIA-ASMM. Thus, decreases in BIA-ASMM and Cr- TSMM were the most consistent markers of aging and sarcopenia. This study may help promote nursing care for healthy aging

Characteristics of systolic and diastolic potentials recorded in the left interventricular septum in verapamil-sensitive left ventricular tachycardia

We studied the electrophysiological characteristics of systolic (SP) and diastolic (DP) potentials recorded during sinus rhythm (SR) in the left interventricular septum of a 27 year-old woman presenting with verapamil-sensitive idiopathic left ventricular tachycardia (VT). During SR, and during VT, SP was activated from ventricular base-to-apex, and DP from apex-to-base. SP and DP were both detected at the site of successful ablation during SR, whereas during VT, DP was detected away from the earliest activation site. Thus, SP apparently reflected a critical component of the reentrant circuit, while DP reflected the activation of a bystander pathway

Irregular atrial flutter following pulmonary vein isolation for persistent atrial fibrillation

AbstractA 65-year-old man with a history of refractory paroxysmal atrial fibrillation (AF) underwent catheter ablation for persistent AF lasting 2 months. AF was not terminated after complete isolation of the 4 pulmonary veins (PV). Instead, it was transformed to a sustained atrial tachyarrhythmia with beat-to-beat variability in the atrial cycle length. A 12-lead electrocardiogram during tachycardia showed negative flutter-like waves in the inferior leads. Entrainment pacing along the tricuspid annulus confirmed the diagnosis of irregular cavotricuspid isthmus (CTI)-dependent typical atrial flutter (AFL). Linear ablation of the CTI terminated AFL and restored sinus rhythm

Typical atrial flutter with atypical flutter wave morphology due to abnormal interatrial conduction

We report a case of typical counterclockwise atrial flutter (AFL) with conduction block from right to left atrium along the coronary sinus (CS) musculature, confirmed by discontinuous CS activation sequence during pacing near the ostium and differential right atrial pacing. AFL was associated with an atypical flutter wave morphology, due to the detour of the activation wavefront from right to left atrium via alternate interatrial electrical connections, such as Bachmann’s bundle, the interatrial septum, or both. (Cardiol J 2011; 18, 4: 450–453

Random Fan-Out State Induced by Site-Random Interlayer Couplings

We study the low-temperature properties of a classical Heisenberg model with site-random interlayer couplings on the cubic lattice. This model is introduced as a simplified effective model of Sr(Fe$_{1-x}$Mn$_{x}$)O$_2$, which was recently synthesized. In this material, when $x=0.3$, $(\pi\pi\pi)$ and $(\pi\pi0)$ mixed ordering is observed by neutron diffraction measurements. By Monte Carlo simulations, we find an exotic bulk spin structure that explains the experimentally obtained results. We name this spin structure the "random fan-out state". The mean-field calculations provide an intuitive understanding of this phase being induced by the site-random interlayer couplings. Since Rietveld analysis assuming the random fan-out state agrees well with the neutron diffraction pattern of Sr(Fe$_{0.7}$Mn$_{0.3}$)O$_2$, we conclude that the random fan-out state is reasonable for the spin-ordering pattern of Sr(Fe$_{0.7}$Mn$_{0.3}$)O$_2$ at the low-temperature phase.Comment: 13 pages, 12 figure

Transcription factors interfering with dedifferentiation induce cell type-specific transcriptional profiles

初期化を阻害する転写因子が分化を促進する. 京都大学プレスリリース. 2013-04-02.Transcription factors (TFs) are able to regulate differentiation-related processes, including dedifferentiation and direct conversion, through the regulation of cell type-specific transcriptional profiles. However, the functional interactions between the TFs regulating different transcriptional profiles are not well understood. Here, we show that the TFs capable of inducing cell type-specific transcriptional profiles prevent the dedifferentiation induced by TFs for pluripotency. Of the large number of TFs expressed in a neural-lineage cell line, we identified a subset of TFs that, when overexpressed, strongly interfered with the dedifferentiation triggered by the procedure to generate induced pluripotent stem cells. This interference occurred through a maintenance mechanism of the cell type-specific transcriptional profile. Strikingly, the maintenance activity of the interfering TF set was strong enough to induce the cell line-specific transcriptional profile when overexpressed in a heterologous cell type. In addition, the TFs that interfered with dedifferentiation in hepatic-lineage cells involved TFs with known induction activity for hepatic-lineage cells. Our results suggest that dedifferentiation suppresses a cell type-specific transcriptional profile, which is primarily maintained by a small subset of TFs capable of inducing direct conversion. We anticipate that this functional correlation might be applicable in various cell types and might facilitate the identification of TFs with induction activity in efforts to understand differentiation