Compressibility of CeMIn5Ce M In_5 and Ce2MIn8Ce_2 M In_8 (M = Rh, Ir and Co) Compounds

The lattice parameters of the tetragonal compounds Ce$M$In$_{5}$ and Ce$_{2}M$In$_{8}$($M=$Rh, Ir and Co) have been studied as a function of pressure up to 15 GPa using a diamond anvil cell under both hydrostatic and quasihydrostatic conditions at room temperature. The addition of $M$In$_{2}$ layers to the parent CeIn$_{3}$ compound is found to stiffen the lattice as the 2-layer systems (average of bulk modulus values $B_{0}$ is 70.4 GPa) have a larger $B_{0}$ than CeIn$_{3}$ (67 GPa), while the 1-layer systems with the are even stiffer (average of $B_{0}$ is 81.4 GPa). Estimating the hybridization using parameters from tight binding calculations shows that the dominant hybridization is $fp$ in nature between the Ce and In atoms. The values of $V_{pf}$ at the pressure where the superconducting transition temperature $T_{c}$ reaches a maximum is the same for all Ce$M$In$_{5}$ compounds. By plotting the maximum values of the superconducting transition temperature $T_{c}$ versus $c/a$ for the studied compounds and Pu-based superconductors, we find a universal $T_{c}$ versus $c/a$ behavior when these quantities are normalized appropriately. These results are consistent with magnetically mediated superconductivity.Comment: Updated version resubmitted to Phys. Rev.

Peculiarities of the emotional state of higher education students depending on the type of learning classes

Розглянуто особливості емоційного стану студентів залежно від виду навчального заняття. Досліджено міру самопочуття студентів та міру активності на лекційних заняттях порівняно з семінарськими і лабораторними; самопочуття та активності на семінарських заняттях порівняно з лабораторними; міру настрою студентів на лекційних заняттях порівняно з семінарськими і лабораторними заняттями,настрою на семінарських заняттях порівняно з лабораторними. З’ясовано, що у студентів самопочуття на лекціях має позитивні ознаки. Порівняно з лекціями, на лабораторних заняттях студенти мають більш позитивно виражене самопочуття. У студентів міравираженості активності більш висока на семінарах, ніж на лекціях. Порівняно з лекціями, на лабораторних заняттях студенти дуже активні. Швидкість і темп протікання психічних функцій студентів під час лабораторних заняттях мають більш високу міру вираженості, ніж під час семінарів. У студентів міра вираженості настрою більш висока на лекціях, ніж на семінарах. У якості перспективного напряму дослідження виділеноаналіз емоційних станів студентів залежно від гендерних особливостей і курсу навчання.Тhe features of emotional state of the students depending on a kind of learning classes are considered. The degree of well-being of students at lectures compared to seminars and laboratory classes, well-being at seminars compared to laboratory classes, the degree of activity of students at lectures compared to seminars and laboratory classes, activity at seminars compared to laboratory classes, the degree of mood of students at lectures compared to seminars and laboratory classes, the mood at seminars compared to laboratory classes have been studied.It has been found that the students have positive feelings at lectures. Compared to lectures, at laboratory classesthe students have positive well-being. The students have a higher degree of activity at seminars than at lectures. Compared to lectures, the students are very active at laboratory classes. The speed and pace of mental functions of the students during laboratory classes are expressed more intensive than during seminars. The students have a higher degree of mood expression at lectures than at seminars. As a promising area of research, the analysis of students' emotional states depending on gender characteristics and the course of study is highlighte

On the impact of nanometric γ’ precipitates on the tensile deformation of superelastic Co49Ni21Ga30

Results are presented reporting on the martensite domain variant selection and stress-induced martensite morphology in [001]-oriented superelastic Co49Ni21Ga30 shape memory alloy (SMA) single crystals under tensile load. In situ neutron diffraction, as well as in situ optical- and confocal laser scanning microscopy were conducted focusing on three differently treated samples, i.e. in the as-grown, solution-annealed and aged condition. An aging treatment performed at 350 °C promotes the precipitation of nanoprecipitates. These second phase precipitates contribute to an increase of the number of habit plane interfaces, while reducing lamellar martensite plate thickness compared to the as-grown and solution-annealed (precipitate free) samples. During tensile loading, all samples show a stress-induced formation of martensite, characterized by one single domain variant (“detwinned”) and one set of parallel habit planes in a shear band. The results clearly show that γ’ nanoprecipitates do not necessarily promote multi-variant interaction during tensile loading. Thus, reduced recoverability in Co-Ni-Ga SMAs upon aging cannot be solely attributed to this kind of interaction as has been proposed in literature so far

Effects of aging on the stress-induced martensitic transformation and cyclic superelastic properties in Co-Ni-Ga shape memory alloy single crystals under compression

Co-Ni-Ga shape memory alloys attracted scientific attention as promising candidate materials for damping applications at elevated temperatures, owing to excellent superelastic properties featuring a fully reversible stress-strain response up to temperatures as high as 500 °C. In the present work, the effect of aging treatments conducted in a wide range of aging temperatures and times, i.e. at 300–400 °C for 0.25–8.5 h, was investigated. It is shown that critical features of the martensitic transformation are strongly affected by the heat treatments. In particular, the formation of densely dispersed γ’-nanoparticles has a strong influence on the martensite variant selection and the morphology of martensite during stress-induced martensitic transformation. Relatively large, elongated particles promote irreversibility. In contrast, small spheroidal particles are associated with excellent functional stability during cyclic compression loading of 〈001〉-oriented single crystals. In addition to mechanical experiments, a detailed microstructural analysis was performed using in situ optical microscopy and neutron diffraction. Fundamental differences in microstructural evolution between various material states are documented and the relations between thermal treatment, microstructure and functional properties are explored and rationalized

The calcium-Activated potassium channel KCa3.1 is an important modulator of hepatic injury

The calcium-Activated potassium channel KCa3.1 controls different cellular processes such as proliferation and volume homeostasis. We investigated the role of KCa3.1 in experimental and human liver fibrosis. KCa3.1 gene expression was investigated in healthy and injured human and rodent liver. Effect of genetic depletion and pharmacological inhibition of KCa3.1 was evaluated in mice during carbon tetrachloride induced hepatic fibrogenesis. Transcription, protein expression and localisation of KCa3.1 was analysed by reverse transcription polymerase chain reaction, Western blot and immunohistochemistry. Hemodynamic effects of KCa3.1 inhibition were investigated in bile duct-ligated and carbon tetrachloride intoxicated rats. In vitro experiments were performed in rat hepatic stellate cells and hepatocytes. KCa3.1 expression was increased in rodent and human liver fibrosis and was predominantly observed in the hepatocytes. Inhibition of KCa3.1 aggravated liver fibrosis during carbon tetrachloride challenge but did not change hemodynamic parameters in portal hypertensive rats. In vitro, KCa3.1 inhibition leads to increased hepatocyte apoptosis and DNA damage, whereas proliferation of hepatic stellate cells was stimulated by KCa3.1 inhibition. Our data identifies KCa3.1 channels as important modulators in hepatocellular homeostasis. In contrast to previous studies in vitro and other tissues this channel appears to be anti-fibrotic and protective during liver injury

Fluid-structure interaction simulation of prosthetic aortic valves : comparison between immersed boundary and arbitrary Lagrangian-Eulerian techniques for the mesh representation

In recent years the role of FSI (fluid-structure interaction) simulations in the analysis of the fluid-mechanics of heart valves is becoming more and more important, being able to capture the interaction between the blood and both the surrounding biological tissues and the valve itself. When setting up an FSI simulation, several choices have to be made to select the most suitable approach for the case of interest: in particular, to simulate flexible leaflet cardiac valves, the type of discretization of the fluid domain is crucial, which can be described with an ALE (Arbitrary Lagrangian-Eulerian) or an Eulerian formulation. The majority of the reported 3D heart valve FSI simulations are performed with the Eulerian formulation, allowing for large deformations of the domains without compromising the quality of the fluid grid. Nevertheless, it is known that the ALE-FSI approach guarantees more accurate results at the interface between the solid and the fluid. The goal of this paper is to describe the same aortic valve model in the two cases, comparing the performances of an ALE-based FSI solution and an Eulerian-based FSI approach. After a first simplified 2D case, the aortic geometry was considered in a full 3D set-up. The model was kept as similar as possible in the two settings, to better compare the simulations' outcomes. Although for the 2D case the differences were unsubstantial, in our experience the performance of a full 3D ALE-FSI simulation was significantly limited by the technical problems and requirements inherent to the ALE formulation, mainly related to the mesh motion and deformation of the fluid domain. As a secondary outcome of this work, it is important to point out that the choice of the solver also influenced the reliability of the final results