On Z-graded loop Lie algebras, loop groups, and Toda equations

Toda equations associated with twisted loop groups are considered. Such equations are specified by Z-gradations of the corresponding twisted loop Lie algebras. The classification of Toda equations related to twisted loop Lie algebras with integrable Z-gradations is discussed.Comment: 24 pages, talk given at the Workshop "Classical and Quantum Integrable Systems" (Dubna, January, 2007

Kinetics of Ordering and Decomposition in Ti-Al-X (X = Si, Zr) Alloys: Monte Carlo Modeling

To investigate the ordering and decomposition processes in Ti-Al-X [X = Si, Zr] alloys, the Monte Carlo simulations with first-principles parametrization of interatomic interactions were employed. It was shown that the processes of ordering and the precipitation in the Ti-Al system are closely related, and the stage of homogeneous ordering precedes the formation of ordered Ti3Al particles. It was found that the duration of homogeneous ordering is very sensitive to the annealing temperature and composition of alloy, and that precipitation becomes preferable as the temperature rises. In particular, uniform ordering of alloy Ti-12 at % Al was found during long-term holding at temperature below 850 K, while annealing at 1000 K resulted in formation of ordered Ti3Al particles. The obtained results agree well with the experimental data and allow explaining the features of the microstructure formed during annealing of the Ti-Al-X alloys. © 2022 by the authors.Ministry of Education and Science of the Russian Federation, Minobrnauka: AAA-A18-118020190116-6The research was carried out within the state assignment of the Ministry of Science and Higher Education of the Russian Federation (topic Structure, No. AAA-A18-118020190116-6)

Free Energy of the Eight Vertex Model with an Odd Number of Lattice Sites

We calculate the bulk contribution for the doubly degenerated largest eigenvalue of the transfer matrix of the eight vertex model with an odd number of lattice sites N in the disordered regime using the generic equation for roots proposed by Fabricius and McCoy. We show as expected that in the thermodynamic limit the result coincides with the one in the N even case.Comment: 11 pages LaTeX New introduction, Method change

Dependent coordinates in path integral measure factorization

The transformation of the path integral measure under the reduction procedure in the dynamical systems with a symmetry is considered. The investigation is carried out in the case of the Wiener--type path integrals that are used for description of the diffusion on a smooth compact Riemannian manifold with the given free isometric action of the compact semisimple unimodular Lie group. The transformation of the path integral, which factorizes the path integral measure, is based on the application of the optimal nonlinear filtering equation from the stochastic theory. The integral relation between the kernels of the original and reduced semigroup are obtained.Comment: LaTeX2e, 28 page

Role of magnetic degrees of freedom in a scenario of phase transformations in steel

The diversity of mesostructures formed in steel at cooling from a high-temperature austenite ("gamma") phase is determined by the interplay of shear reconstructions of crystal lattice and diffusion of carbon. Combining first-principles calculations with large-scale phase-field simulations we demonstrate a decisive role of magnetic degrees of freedom in the formation of energy relief along the Bain path of "gamma"-"alpha" transformation and, thus, in this interplay. We show that there is the main factor, namely, the magnetic state of iron and its evolution with temperature which controls the change in character of the transformation. Based on the computational results we propose a simple model which reproduces, in good agreement with experiment, the most important curves of the phase transformation in Fe-C, namely, the lines relevant to a start of ferrite, bainite, and martensite transformations. Phase-field simulations within the model describe qualitatively typical patterns at these transformations

Polypropylene suture material with anti-inflammatory action

© 2018, Iran Polymer and Petrochemical Institute. Polypropylene (PP) monofilament threads are widely used as surging sutures. Functionalization of their surface to impart new properties is of great importance and interest for medicine. This work provides an efficient approach for chemical activation of PP surface followed by anchoring of anti-inflammatory materials (aspirin and indomethacin). Two chemical routes for activation of PP surface and two anti-inflammatory substances were combined, giving a set of four different functionalized threads. Efficiency in terms of anti-inflammatory action of resultant hybrid materials was proved by ligation of wounds made along the spine of mice with further monitoring of inflammation process. In vivo test on mice showed the best healing of surgical skin wounds by means of suture activated by 45% H2O2 solution in the presence of FeSO4 as catalyst at 60 °C for 2 h, which was then modified with aspirin. Plasma interleukin measurement and histological section experiment were performed to prove the efficiency of the threads used for tissue connection. Highest healing efficiency of the suture is obviously explained by higher containment of anti-inflammatory substance anchored on PP surface. The work provides data on a cheap and easy implementation method for novel hybrid materials in medical applications that are able to perform accurately on surgical intervention sites

In vivo MRI visualization of growth and morphology in the orthotopic xenotrasplantation U87 glioblastoma mouse SCID model

Glioblastoma multiforme (GBM) is the most common and lethal type of brain cancer with the average lifespan of patients about 9–12 months. The study of tumor formation and the evaluation of new therapies for GBM require accurate and reproducible experimental brain tumor animal models. In this study we used MRI for investigation of tumor morphology and growth dynamic in an orthopic xenotransplantation immunodeficient mouse model (SCID mouse line). Comparison of T1- and T2-weighed MRI scans preformed with a high-field MRI scanner (Bruker, BioSpec, 11,7 T) revealed insufficient tumor/normal tissue T1-contrast because of high longitudinal magnetization of the magnetic field in our scanner. Intravenous injection of paramagnetic manganese oxide (MnO) nanoparticles dramatically increased the tumor/normal tissue contrast in T1-weigthed MRI scans. The study of glioblastoma growth with T2-weighed images showed that a significant tumor development began not earlier than 3 weeks after cell culture intracranial injection and then the tumor grew exponentially. Thus, we developed a protocol of the characterization of glioblastoma U87 growth and morphology by T1- and T2-weighed and MnO-enhanced MRI in the orthopic xenotransplantation mouse model. The results demonstrate that this SCID model may be used as an in vivo preclinical model to test the efficacy and putative side effects of novel anticancer therapies

Luminescence of LaBr3:Ce,Hf scintillation crystals under UV-VUV and X-ray excitation

The present study was carried out by means of the low temperature time-resolved luminescence UV–VUV spectroscopy as well as the optical and thermally activation spectroscopy. The Ce3+ centers in regular lattice sites and located in the vicinity of the point defects of crystal structure were observed. Spectral and kinetic characteristics of the luminescence of these centers were defined. A photoluminescence of new point defects of the crystal structure are also manifested. We evaluated the energy of the interband transitions as Eg ≈ 6.2 eV in LaBr3. At the excitation energies Eexc>13 eV (higher than 2Eg) the effect of the electronic excitations multiplication was detected