Electro-explosive alloying of VT6 alloy surface by boron carbide powder with the subsequent electron-beam treatment

The formation of electro-explosive alloying zone with the thickness up to 50 µm has been revealed. It has been shown that it has a gradient structure, characterized by the decrease of carbon and boron concentration with the increase of the distance up to the treatment surface. The subsequent electron-beam treatment of alloying zone leads to flattening of alloying surface relief and is accompanied by the formation of a multilevel structure at the depth up to 30 µm, characterized by the interchange of some layers with a different level of alloying, having structure of a submicro- and nanoscale level

The accumulation of femtosecond laser radiation energy in crystals of lithium fluoride

We present the results of studies of energy accumulation during the non-destructive interaction of extremely intense near infrared laser radiation with model wide band gap dielectric crystals of lithium fluoride, when the intensity of pulses is sufficient for effective highly nonlinear absorption of light and for the excitation of the electron subsystem of matter and the energy of pulses is still not sufficient for significant heating, evaporation, laser breakdown or other destruction to occur. We studied the emission of energy in the form of light sum of thermally stimulated luminescence accumulated under conditions of self-focusing and multiple filamentation of femtosecond laser radiation. It was established that it's the F2 and F[3]{+} color centers and supplementary to them centers of interstitial type which accumulate energy under the action of a single femtosecond laser pulses. When irradiated by series of pulses the F3, F[3]{-} and F[4] centers additionally appear. F2 centers are the main centers of emission in the process of thermally stimulated luminescence of accumulated energy. The interstitial fluoride ions (I-centers) are the kinetic particles. They split off from the X[3]{-} centers in the result of thermal decomposition of latter on the I-centers and molecules X[2]{0}. I-centers recombine with F[3]{+} centers and form F[2] centers in excited state. The latter produce the characteristic emission spectrum emitted in the form of thermally stimulated luminescence

Fabrication of endothelial cell-laden carrageenan microfibers for microvascularized bone tissue engineering applications

ecent achievements in the area of tissue engineering (TE) have enabled the development of three-dimensional (3D) cell-laden hydrogels as in vitro platforms that closely mimic the 3D scenario found in native tissues. These platforms are extensively used to evaluate cellular behavior, cell-cell interactions, and tissue-like formation in highly defined settings. In this study, we propose a scalable and flexible 3D system based on microsized hydrogel fibers that might be used as building blocks for the establishment of 3D hydrogel constructs for vascularized bone TE applications. For this purpose, chitosan (CHT) coated κ-carrageenan (κ-CA) microfibers were developed using a two-step procedure involving ionotropic gelation (for the fiber formation) of κ-CA and its polyelectrolyte complexation with CHT (for the enhancement of fiber stability). The performance of the obtained fibers was assessed regarding their swelling and stability profiles, as well as their ability to carry and, subsequently, promote the outward release of microvascular-like endothelial cells (ECs), without compromising their viability and phenotype. Finally, the possibility of assembling and integrating these cell-laden fibers within a 3D hydrogel matrix containing osteoblast-like cells was evaluated. Overall, the obtained results demonstrate the suitability of the microsized κ-CA fibers to carry and deliver phenotypically apt microvascular-like ECs. Furthermore, it is shown that it is possible to assemble these cell-laden microsized fibers into 3D heterotypic hydrogels constructs. This in vitro 3D platform provides a versatile approach to investigate the interactions between multiple cell types in controlled settings, which may open up novel 3D in vitro culture techniques to better mimic the complexity of tissues.Authors thank the Portuguese Foundation for Science and Technology (FCT) for the personal grants SFRH/BD/42968/2008 through the MIT-Portugal Program (SMM) and SFRH/BD/64070/2009 (EGP). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS and MIT/ECE/0047/2009 project

Nanostructuring of a Surface Layer as a Way to Improve the Mechanical Properties of Hypoeutectic Silumin

The irradiation of hypoeutectic silumin 383.1 with an intense pulsed electron beam in the melting mode and rapid crystallization of the surface layer has been performed. A multiphase submicron nanostructured surface layer with a thickness of up to 70 nm has been formed. Mechanical tests of the irradiated silumin samples in tensile experiments have been carried out. A significant increase in strength and plastic properties of silumin irradiated with an electron beam has been established. Features and patterns in the distribution of displacement fields in the deformation process in surface layers of the samples in realtime have been identified by digital image correlation method using the optical measuring system VIC-3D

Nanostructuring of a Surface Layer as a Way to Improve the Mechanical Properties of Hypoeutectic Silumin

The irradiation of hypoeutectic silumin 383.1 with an intense pulsed electron beam in the melting mode and rapid crystallization of the surface layer has been performed. A multiphase submicron nanostructured surface layer with a thickness of up to 70 nm has been formed. Mechanical tests of the irradiated silumin samples in tensile experiments have been carried out. A significant increase in strength and plastic properties of silumin irradiated with an electron beam has been established. Features and patterns in the distribution of displacement fields in the deformation process in surface layers of the samples in realtime have been identified by digital image correlation method using the optical measuring system VIC-3D

Study of the stochastic clustering on the refractory material surface under the effect of plasma load in the PLM device

Tungsten plates were tested in stationary helium discharges in the PLM device. The duration of discharges in the PLM reached 200 minutes. A distinctive feature of this device is the stationary plasma confinement, which is advantageous for testing fusion materials, including materials of the divertor and first wall of a fusion reactor. During plasma irradiation in the PLM, the thermal load on the surface of the tested plates was more than 1 MW/m(2). The temperature of the tested plates amounted to 1000 degrees C and more. Stochastic nanostructures with dimensions of the structural elements of less than 50 nm, including fuzz-type structures, were observed on the processed surfaces of the samples

Impact of liquid metal surface on plasma-surface interaction in experiments with lithium and tin capillary porous systems

The lithium and tin capillary-porous systems (CPSs) were tested with steady-state plasma in the PLM plasma device which is the divertor simulator with plasma parameters relevant to divertor and SOL plasma of tokamaks. The CPS consists of tin/lithium tile fixed between two molybdenum meshs constructed in the module faced to plasma. Steady-state plasma load of 0.1 - 1 MW/m(2) on the CPS during more than 200 min was achieved in experiments on PLM which is a modeling far scrapeoff- layer and far zone of divertor plasma of a large tokamak. The heating of the CPS was controlled remotely including biasing technique which allows to regulate evaporated metal influx to plasma. After exposure, the materials of the tin and lithium CPSs were inspected and analyzed with optic and scanning electron micriscopy. Experiments have demonstrated sustainability of the tin and lithium CPSs to the high heat steady state plasma load expected in a large scale tokamak. The effect of evaporated lithium and tin on the plasma transport/radiation was studied with spectroscopy to evaluate changes of plasma properties and plasma-surface interaction

System of Monitoring and Response to Public Health Emergencies of Sanitary-Epidemiological Character in the CIS Countries

The most important component of strengthening the potential for responding to biological threats both at the national and interstate levels is the formation of a unified system for monitoring and responding to emergencies (ES) of sanitary-epidemiological nature in the CIS territory.The aim of the work was to review the systems for monitoring and responding to emergencies of sanitary-epidemiological character in the CIS countries by the example of the Russian Federation, the Republic of Belarus, the Republic of Kazakhstan and the Kyrgyz Republic, to characterize the main areas of international cooperation on countering biological threats and coordinating international response measures in the CIS countries.Materials and methods. Information and analytical materials provided by organizations responsible for epidemiological surveillance and control in the CIS countries, Internet sources, and publications were used for the study.Results and discussion. The organization and functioning of the systems for monitoring and responding to emergencies in the CIS countries is a state function. It includes, as a rule, the national, regional (sub-national) and territorial (local) levels, which have horizontal and vertical connections. The legal framework is made up of documents of the legislative level. Interdepartmental interaction in response to emergencies is carried out both at the republican level and in administrative territories; the basis for interaction is the integrated planning of preventive and anti-epidemic measures and the functioning of the relevant organizational structures on an ongoing basis. Since 2015, with the support of the Government of the Russian Federation, programs have been implemented aimed at assisting partner countries in the implementation of the International Health Regulations (2005) in order to increase national response capacity and form a unified sanitaryepidemiological emergency response system in the CIS countries. The main areas of collaboration are strengthening the material and technical base and human resources of specialized institutions and scientific cooperation. As a result of the program implementation, a unified system for monitoring and prompt response to emergencies in the field of public health of sanitary-epidemiological nature has essentially been formed in the CIS countries to date, uniting more than 15 specialized institutions from 8 CIS countries

Biofabrication: an overview of the approaches used for printing of living cells

The development of cell printing is vital for establishing biofabrication approaches as clinically relevant tools. Achieving this requires bio-inks which must not only be easily printable, but also allow controllable and reproducible printing of cells. This review outlines the general principles and current progress and compares the advantages and challenges for the most widely used biofabrication techniques for printing cells: extrusion, laser, microvalve, inkjet and tissue fragment printing. It is expected that significant advances in cell printing will result from synergistic combinations of these techniques and lead to optimised resolution, throughput and the overall complexity of printed constructs