Effect of plastic deformation on a dispersion of omega-phase and mechanical properties of an Al-Cu-Mg-Ag alloy

Effect of cold rolling prior to ageing on a dispersion of secondary phases and mechanical properties at room temperature for an Al-5.6Cu-0.72Mg-0.5Ag-0.32Mn-0.17Sc-0.12Zr (wt. %) alloy, which was solution treated and water quenched initially, was examined. It was shown that cold working leads to significant increase in density of lattice dislocations that induces the formation discrete agglomerates of the θ¢-phase on the {100} planes. Strain of 7% provided increased aspect ratio (length to thickness) of plates that leads to moderate increase of strength. Imposing of higher strains leads to increased lattice dislocation density and the formation of deformation-induced boundarie

Effect of cold plastic deformation prior to ageing on creep resistance of an Al-Cu-Mg-Ag alloy

Effect of thermomechanical processing on creep resistance at 150°C of an Al-5.6Cu- 0.72Mg-0.5Ag-0.32Mn-0.17Sc-0.12Zr (wt. %) alloy was examined. It was shown that increasing strain prior to artificial aging provides achieving high strength. However, a degradation of the creep resistance, i.e., significant decrease in the rupture time and increase in the minimal creep rate, took place, concurrently. The effect of cold rolling on the strength and creep resistance is discussed in relation with the strain effect on the dispersion of secondary phase

Effect of thermally treated wood

There are many studies on the thermal treatment of wood, but the treatment of thermally modified wood with different flame retardants, and the changes that occur in this process are not fully understood. This paper assesses various thermal modifications and the flame retardant effect on thermally modified wood under conditions that simulate the natural process of wood combustion by a heat source, constant air flow and exhaust gas flow. The research temperature ranges from 160 to 260 C. It has been experimentally proven that thermally modified wood impregnated with a fire retardant has a greater fire and ignition resistance than untreated wood. © Published under licence by IOP Publishing Ltd

Small Scale Anisotropy Predictions for the Auger Observatory

We study the small scale anisotropy signal expected at the Pierre Auger Observatory in the next 1, 5, 10, and 15 years of operation, from sources of ultra-high energy (UHE) protons. We numerically propagate UHE protons over cosmological distances using an injection spectrum and normalization that fits current data up to \sim 10^{20}\eV. We characterize possible sources of ultra-high energy cosmic rays (UHECRs) by their mean density in the local Universe, $\bar{\rho} = 10^{-r}$ Mpc$^{-3}$, with $r$ between 3 and 6. These densities span a wide range of extragalactic sites for UHECR sources, from common to rare galaxies or even clusters of galaxies. We simulate 100 realizations for each model and calculate the two point correlation function for events with energies above 4 \times 10^{19}\eV and above 10^{20}\eV, as specialized to the case of the Auger telescope. We find that for r\ga 4, Auger should be able to detect small scale anisotropies in the near future. Distinguishing between different source densities based on cosmic ray data alone will be more challenging than detecting a departure from isotropy and is likely to require larger statistics of events. Combining the angular distribution studies with the spectral shape around the GZK feature will also help distinguish between different source scenarios.Comment: 15 pages, 6 figures, 6 tables, submitted to JCA

C-kit-positive progenitor cells activation in rats pancreas after partial hepatectomy

One of the most common markers of pancreas stem cells is a stem cell factor receptor C-kit. According to some authors, this marker is presented in islet cells of normal rat pancreas. But it is unknown about the behavior of these cells in disorders of carbohydrate metabolism during liver disease. The aim of our study was to evaluate C-kit expression in pancreas after partial hepatectomy in rats. Partial hepatectomy was performed for 27 white male rats. The expression of C-kit, insulin and glucagon in rats pancreas was studied. The expression of C-kit in islets and interstitial cells was shown in results after 3 days of the experiment, and double staining showed that these cells can express glucagon. Thus, there is the activation of C-kit+ progenitor cells in pancreas after partial hepatectomy and the beginning of there differentiation to α-cells of Langerhance islets

Changes of liver microstructure after partial hepatectomy in rats

Ability of mammalian liver to regenerate is one of the favorite examples of "regenerative medicine". At the same time liver regeneration can not be viewed as a simple hypertrophy, it must have some appropriate steps. Understanding of these processes is crucial for correct interpretation of liver therapy results, especially after cellular therapy. But, unfortunately, original and first-hand data regarding changes in liver microstructure during regeneration is relatively scarce. This work was dedicated to study changes of liver microstructure during liver regeneration after partial hepatectomy in rats. We analyzed proliferative processes, perisinusoidal cells involvement, sizes of classical hepatic lobules, participation of bile ducts, branches of afferent and efferent hepatic vessels in liver regeneration on 1, 2, 3, 5, 7 postoperative days. Our results have shown that liver microstructure during regeneration after partial hepatectomy undergoes two stages: hypertrophy of hepatic lobules by proliferation of liver cells until 4th day and division of hepatic lobules by branching of bile ducts, hepatic artery, portal and central veins from 4th until 7th postoperative day. © Human stem cells institute, 2013

Diffusion of Cosmic Rays in the Expanding Universe. II. Energy Spectra of Ultra-High Energy Cosmic Rays

We consider the astrophysical implications of the diffusion equation solution for Ultra-High Energy Cosmic Rays (UHECR) in the expanding universe, obtained in paper I (V.Berezinsky & A.Gazizov, ApJ 643 (2006) 8). The UHECR spectra are calculated in a model with sources located in vertices of the cubic grid with a linear constant (source separation) d. The calculations are performed for various magnetic field configurations (B_c,l_c), where l_c is the basic scale of the turbulence and B_c is the coherent magnetic field on this scale. The main purpose of these calculations is to demonstrate the validity of the solution obtained in paper I and to compare this solution with the Syrovatsky solution used in previous works. The Syrovatsky solution must be necessarily embedded in the static cosmological model. The formal comparison of the two solutions with all parameters being fixed identically reveals the appreciable discrepancies between two spectra. These discrepancies are less if in both models the different sets of the best-fit parameters are used.Comment: 17 pages, 10 figure

Suppression of abnormal grain growth in friction-stir welded aluminum by pre-strain rolling: Limitation of the approach

This work emphasizes the limited efficiency of the pre-straining approach for suppression of abnormal grain growth in friction-stir welds produced at low-heat-input conditions. In this case, the introduced dislocation density is insufficient to overbalance grain-boundary energy. Hence, the subsequent annealing behavior is governed by the grain growth rather than recrystallizatio

Long-term results of autologous peripheral blood hematopoietic stem cell transplantation in patients with peripheral arterial diseases

The aim of our work was to assess long-term results of autologous peripheral blood hematopoietic stem cell application in patients with peripheral arterial diseases. Peripheral blood hematopoietic stem cells mobilized by granulocyte colony-stimulating factor were transplanted intramuscularly to 30 patients with peripheral arterial diseases (IIb stage by Pokrovsky). Standart tredmill test, anklebrachial index estimation and ankle-brachial index restoration time estimation after loading were performed on 0, 3, 6, 12 and 60 months after transplantation. Immunohistochemical study of injured gastrocnemius muscle biopsies taken before peripheral blood hematopoietic stem cells transplantation and 3 months after the procedure was performed. Peripheral blood hematopoietic stem cells transplantation increases capillary density (22,4%, p = 0,0005). Anklebrachial index increased by 18,1% on month 6 after transplantation without a tendency to change on month 12. 60 months after transplantation initial to hematopoietic stem cells transplantation ankle-brachial index rates were marked. Painless walking distance was increasing at all times of observation progressively, on month 60 no walking distance limitation was marked by most patients. Ankle-brachial index restoring time shows positive trend of the functional state of limb during the first year after transplantation, 60 months after transplantation it showed no «walking reserve» limitation in most patients. 5-years survival was 79%, death causes were stroke, cardiac pathology (3 cases), lung cancer. So, peripheral blood hematopoietic stem cells transplantation allows eliminating peripheral arterial diseases symptoms and preserving limb in long-term period. Autologous transplantation of peripheral blood hematopoietic stem cells has no complications and is safe for therapy of patients with peripheral arterial diseases II stage. © Human stem cells institute, 2013

Conservation laws for self-adjoint first order evolution equations

In this work we consider the problem on group classification and conservation laws of the general first order evolution equations. We obtain the subclasses of these general equations which are quasi-self-adjoint and self-adjoint. By using the recent Ibragimov's Theorem on conservation laws, we establish the conservation laws of the equations admiting self-adjoint equations. We illustrate our results applying them to the inviscid Burgers' equation. In particular an infinite number of new symmetries of these equations are found and their corresponding conservation laws are established.Comment: This manuscript has been accepted for publication in Journal of Nonlinear Mathematical Physic