Availability of organs is a limiting factor for lung transplantation, leading to substantial mortality rates on the wait list. Use of organs from donors with transmissible viral infections, such as ...hepatitis C virus (HCV), would increase organ donation, but these organs are generally not offered for transplantation due to a high risk of transmission. Here, we develop a method for treatment of HCV-infected human donor lungs that prevents HCV transmission. Physical viral clearance in combination with germicidal light-based therapies during normothermic ex-vivo Lung Perfusion (EVLP), a method for assessment and treatment of injured donor lungs, inactivates HCV virus in a short period of time. Such treatment is shown to be safe using a large animal EVLP-to-lung transplantation model. This strategy of treating viral infection in a donor organ during preservation could significantly increase the availability of organs for transplantation and encourages further clinical development.
Plastoquinone, a very effective electron carrier and antioxidant of chloroplasts, was conjugated with decyltriphenylphosphonium to obtain a cation easily penetrating through membranes. This cation, ...called SkQ1, is specifically targeted to mitochondria by electrophoresis in the electric field formed by the mitochondrial respiratory chain. The respiratory chain also regenerates reduced SkQ1H(2) from its oxidized form that appears as a result of the antioxidant activity of SkQ1H(2). SkQ1H(2) prevents oxidation of cardiolipin, a mitochondrial phospholipid that is especially sensitive to attack by reactive oxygen species (ROS). In cell cultures, SkQ1 and its analog plastoquinonyl decylrhodamine 19 (SkQR1) arrest H(2)O(2)-induced apoptosis. When tested in vivo, SkQs (i) prolong the lifespan of fungi, crustaceans, insects, fish, and mice, (ii) suppress appearance of a large number of traits typical for age-related senescence (cataract, retinopathies, achromotrichia, osteoporosis, lordokyphosis, decline of the immune system, myeloid shift of blood cells, activation of apoptosis, induction of β-galactosidase, phosphorylation of H2AX histones, etc.) and (iii) lower tissue damage and save the lives of young animals after treatments resulting in kidney ischemia, rhabdomyolysis, heart attack, arrhythmia, and stroke. We suggest that the SkQs reduce mitochondrial ROS and, as a consequence, inhibit mitochondria-mediated apoptosis, an obligatory step of execution of programs responsible for both senescence and fast "biochemical suicide" of an organism after a severe metabolic crisis.
New approach to fabricate diamond diffractive optical elements (DOEs) with continuous relief for powerful CO2 lasers is proposed and tested. It involves short-pulse laser microstructuring of a ...silicon wafer, which further is used as a substrate for polycrystalline diamond growth in a microwave plasma-assisted CVD process. After fine mechanical polishing of the growth side of the diamond film, the silicon substrate is removed via chemical etching. Two different DOEs providing close to 100% diffraction efficiency were fabricated with this technique: cylindrical Fresnel lens with kinoform surface profile and three-beam splitter with continuous microrelief. Optimization of the laser processing conditions has made possible to reduce the final roughness of the structured diamond surface to 200–400 nm depending on the local relief depth (0–7 μm). Both DOEs tested with a CO2 laser have demonstrated high transparency and diffraction efficiency, as well as low radiation scattering of the IR radiation at the surface irregularities.
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•Diamond diffractive optics is produced by replication of laser-structured Si templates.•Cylindrical Fresnel lens and three-beam splitters for CO2 laser are demonstrated.•Optimization of laser processing reduces final surface roughness down to 200–400 nm.•The optical elements showed high transparency and diffraction efficiency in IR range.
•A 3D model of heat transfer in inhomogeneous materials is developed.•The laser welding of dissimilar metals using intermediate insert is studied.•As result of numerical modeling the optimal welding ...parameters are found.
A 3D model of heat transfer in inhomogeneous materials taking into account phase transitions for analysis of laser welding of dissimilar metals using intermediate insert is developed. Based on the proposed model, an algorithm is constructed and numerical studies are carried out of the distribution of temperature fields in the weld joint of titanium and stainless steel with an intermediate copper insert. The processes of melting, evaporation, and solidification of the materials depending on the beam power, its speed, and position of the focal spot in the system are studied. The welding modes reducing interaction of elements of the materials welded and, thus, preventing formation of brittle intermetallic phases in the weld joint are found.
In this paper, we discuss the effect of destabilization of dark states in
88
Sr
1+
ions in an external magnetic field, provides theoretical calculations to describe the effect, describes the systems ...of magnetic field generation and changes in the polarization of laser radiation, and analyzes the experiment and the obtained dependences.
In the paper, we describe a method for searching for the optimal parameters of laser cooling of strontium ions without observing the luminescence signal. The presented method made it possible to ...obtain a cold cloud of ions, detect the luminescence signal, and achieve the mode of ionic crystals.
Barometric Distribution of Hard Sphere Gas Cherepanov, I. N.; Krauzin, P. V.
Journal of applied mechanics and technical physics,
11/2019, Volume:
60, Issue:
6
Journal Article
Peer reviewed
Gas particle distribution simulated by hard spheres and located in a gravitational field at a constant temperature is under study. A hard sphere model is poorly applicable to real gases, but it can ...be used to describe the distribution of nanoparticles in a colloidal suspension. Various models of weakly nonideal gas are compared: virial expansion up to a second coefficient, a Wertheim-Thiel equation in a Percus-Yevick approximation, and a Carnahan-Starling approximation. In the case of virial expansion, an exact analytical solution for an equation of particle distribution by height is obtained. For more complex models, solutions are found using numerical methods. It is shown that accounting for a finite particle size leads to significant changes in the particle distribution as compared to the ideal gas distribution even at small volume fractions. The results obtained using virial expansion are in good agreement with the results obtained using more complex models provided that the volume fraction of the impurity does not exceed 0.1.
Colloidal suspensions can be considered as continuous media, like molecular solutions, in the main area of theoretical research. However, they have a number of features that distinguish them from ...true solutions and coarse suspensions. The paper considers the thermodynamic theory of weak solutions as applied to colloidal suspensions that are in a gravity field. This problem is not clear because the colloidal suspensions are multi component systems, and, strictly, the mutual influence of the suspended particles and the liquid carrier molecules should be taken into account in thermodynamic models. It is shown that the distribution of nanoparticles by height is determined by the density of the mixture as a whole, and not by the density of the dispersion medium. Equations describing the equilibrium distribution of nanoparticles in a colloidal solution have been obtained. Investigation of the dependence of the density on the impurity concentration in a weak solution has shown that if the additivity properties of the component volumes are preserved, then the quadratic coefficient in the Gibbs energy expansion does not depend on pressure. It is shown that the theory of a weak solution gives an equation for the equilibrium distribution of the dispersed phase, which has almost identical solutions for a large range of parameters of a problem with a well-known in the literature equation obtained in the framework of the hard sphere gas model. However, the individual contributions to the thermodynamic potential of the solution (specialized by the field of gravity and interparticle interaction) in the models under consideration are different. These differences can occur in non-equilibrium processes or in the presence of additional flows of a substance (magnetophoresis, thermal diffusion, etc.).
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