РАССЕЯНИЕ ФЛУОРЕСЦЕНТНОГО РЕНТГЕНОВСКОГО ИЗЛУЧЕНИЯ В ВЕЩЕСТВЕ

During the study the X-ray K-spectra of the elements of the middle of periodic system in the media with the small effective atomic numbers on the energy-dispersion spectrometer with the semiconductor detector, experimentally discovered the previously not noted in the scientific publications appearance of peaks of incoherently scattered radiation Kα-lines of the elements of sample. These peaks, which are practically absent for Co, grow for the more heavy elements. Their intensities reach, for example for Ka line of Sn, to 10-15% of the intensity of fluorescent peak. In contrast to the peaks of incoherently scattered radiation of the characteristic anode emission of X-ray tubes, these peaks adjoin close to the fluorescent peak, forming the continuous region of incoherent scattering. This is caused by the broad band of scattering angles (from 0 to 180o). Appearance in the spectra of the peaks of the incoherently scattered characteristic lines of the elements of the sample leads to the need for their account because of the possibility of their superposition on the characteristic lines of other elements. Furthermore, the appearance of the incoherently scattered lines leads to the decrease of the intensities of the corresponding fluorescent lines.Keywords: x-ray spectrometer, semiconductor detector, incoherent dispersion of fluorescent radiation.(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.4.002B.D. Kalinin, R.I. Plotnikov “Pretsizion Tekhnologies” Co. Lt., St. Petersburg, Russian Federation При изучении рентгеновских К-спектров элементов середины периодической системы в материалах с малыми эффективными атомными номерами на энергодисперсионном спектрометре с полупроводниковым детектором, экспериментально обнаружено ранее не отмеченное в научных публикациях появление пиков некогерентно рассеянного излучения Kα-линий элементов образца. Эти пики, практически отсутствующие у Co, возрастают для более тяжелых элементов. Их интенсивность доходит, например для Ka-линии Sn, до 10-15 % от интенсивности флуоресцентного пика. В отличие от пиков некогерентно рассеянного излучения характеристического излучения анодов рентгеновских трубок, эти пики вплотную примыкают к флуоресцентному пику, образуя непрерывную область некогерентного рассеяния. Это обусловлено широким диапазоном углов рассеяния (от 0 до 180o). Появление в спектрах пиков некогерентно рассеянных характеристических линий элементов образца ведет к необходимости их учета из-за возможности их наложения на характеристические линии других элементов. Кроме того, появление некогерентно рассеянных линий ведет к уменьшению интенсивностей соответствующих флуоресцентных линий.Ключевые слова: рентгеновский спектрометр, полупроводниковый детектор, некогерентное рассеяние флуоресцентного излучения.DOI: http://dx.doi.org/10.15826/analitika.2013.17.4.00

Choice of parameters and stability of nonlinear vibration isolation device

Work of active vibration isolation devices with single-mass electromagnetic suspension taking into account of real characteristics of the voltage regulators is described. The analytical researches are carried out; the areas of stability of work of nonlinear vibration isolation device are defined

Hippocampal neurogenesis in the new model of global cerebral ischemia

The study aimed to evaluate the changes of hippocampal neurogenesis in a new model of global transient cerebral ischemia which was performed by the occlusion of the three main vessels (tr. brachiocephalicus, a. subclavia sinistra, and a. carotis communis sinistra) branching from the aortic arch and supplying the brain. Global transitory cerebral ischemia was modeled on male rats (weight = 250–300 g) under chloral hydrate with artificial lung ventilation. Animals after the same surgical operation without vessel occlusion served as sham-operated controls. The number of DCX-positive (doublecortin, the marker of immature neurons) cells in dentate gyrus (DG) and CA1-CA3 fields of hippocampus was counted at the 31st day after ischemia modeling. It was revealed that global cerebral ischemia decreased neurogenesis in dentate gyrus in comparison with the sham-operated group (P<0.05) while neurogenesis in CA1-CA3 fields was increased as compared to the control (P<0.05)

Anomalous Behavior near T_c and Synchronization of Andreev Reflection in Two-Dimensional Arrays of SNS Junctions

We have investigated low-temperature transport properties of two-dimensional arrays of superconductor--normal-metal--superconductor (SNS) junctions. It has been found that in two-dimensional arrays of SNS junctions (i) a change in the energy spectrum within an interval of the order of the Thouless energy is observed even when the thermal broadening far exceeds the Thouless energy for a single SNS junction; (ii) the manifestation of the subharmonic energy gap structure (SGS) with high harmonic numbers is possible even if the energy relaxation length is smaller than that required for the realization of a multiple Andreev reflection in a single SNS junction. These results point to the synchronization of a great number of SNS junctions. A mechanism of the SGS origin in two-dimensional arrays of SNS junctions, involving the processes of conventional and crossed Andreev reflection, is proposed.Comment: 5 pages, 5 figure

Observational Evidence for the Associated Formation of Blobs and Raining Inflows in the Solar Corona

The origin of the slow solar wind is still a topic of much debate. The continual emergence of small transient structures from helmet streamers is thought to constitute one of the main sources of the slow wind. Determining the height at which these transients are released is an important factor in determining the conditions under which the slow solar wind forms. To this end, we have carried out a multipoint analysis of small transient structures released from a north-south tilted helmet streamer into the slow solar wind over a broad range of position angles during Carrington Rotation 2137. Combining the remote-sensing observations taken by the Solar-TErrestrial RElations Observatory (STEREO) mission with coronagraphic observations from the SOlar and Heliospheric Observatory (SOHO) spacecraft, we show that the release of such small transient structures (often called blobs), which subsequently move away from the Sun, is associated with the concomitant formation of transient structures collapsing back toward the Sun; the latter have been referred to by previous authors as "raining inflows." This is the first direct association between outflowing blobs and raining inflows, which locates the formation of blobs above the helmet streamers and gives strong support that the blobs are released by magnetic reconnection.Peer reviewe

Proximity effects and Andreev reflection in mesoscopic SNS junction with perfect NS interfaces

Low temperature transport measurements on superconducting film - normal metal wire - superconducting film (SNS) junctions fabricated on the basis of 6 nm thick superconducting polycrystalline PtSi films are reported. The structures with the normal metal wires of two different lengths L=1.5 $\mu$m and L=6$\mu$m and the same widths W=0.3$\mu$m are studied. Zero bias resistance dip related to pair current proximity effect is observed for all junctions whereas the subharmonic energy gap structure originating from phase coherent multiple Andreev reflections have occurs only in the SNS junctions with short wires.Comment: ReVTex, 4 pages, 4 eps figures include

The first clinical experience of direct gene therapy using VEGF and bFGF in treatment patients with critical lower limb ischemia

In this paper we present the clinical observation of successful treatment of distal form of peripheral artery disease of the lower extremity with symptoms of critical ischemia in a 60 years old patient. Intramuscular injection of dual expression plasmid, encoding vascular endothelial growth factor VEGF and basic fibroblast growth factor FGF2, was performed to the affected lower extremity. The effect of treatment was evaluated by functional tests: measurement of ankle-brachial index, treadmill test, the recovery time, shoulder-ankle index after strain and temporary occlusion. Performed immunohistochemical examination of biopsy samples of the affected lower extremity muscles

Connecting the Properties of Coronal Shock Waves with Those of Solar Energetic Particles

We develop and exploit a new catalog of coronal pressure waves modeled in 3D to study the potential role of these waves in accelerating solar energetic particles (SEPs) measured in situ. Our sample comprises modeled shocks and SEP events detected during solar cycle 24 observed over a broad range of longitudes. From the 3D reconstruction of shock waves using coronagraphic observations we derived the 3D velocity along the entire front as a function of time. Combining new reconstruction techniques with global models of the solar corona, we derive the 3D distribution of basic shock parameters such as Mach numbers, compression ratios, and shock geometry. We then model in a time-dependent manner how the shock wave connects magnetically with spacecraft making in situ measurements of SEPs. This allows us to compare modeled shock parameters deduced at the magnetically well-connected regions, with different key parameters of SEPs such as their maximum intensity. This approach accounts for projection effects associated with remote-sensing observations and constitutes the most extensive study to date of shock waves in the corona and their relation to SEPs. We find a high correlation between the maximum flux of SEPs and the strength of coronal shock waves quantified, for instance, by the Mach number. We discuss the implications of that work for understanding particle acceleration in the corona

The first widespread solar energetic particle event of solar cycle 25 on 2020 November 29 : Shock wave properties and the wide distribution of solar energetic particles

Context. On 2020 November 29, an eruptive event occurred in an active region located behind the eastern solar limb as seen from Earth. The event consisted of an M4.4 class flare, a coronal mass ejection, an extreme ultraviolet (EUV) wave, and a white-light (WL) shock wave. The eruption gave rise to the first widespread solar energetic particle (SEP) event of solar cycle 25, which was observed at four widely separated heliospheric locations (similar to 230 degrees). Aims. Our aim is to better understand the source of this widespread SEP event, examine the role of the coronal shock wave in the wide distribution of SEPs, and investigate the shock wave properties at the field lines magnetically connected to the spacecraft. Methods. Using EUV and WL data, we reconstructed the global three-dimensional structure of the shock in the corona and computed its kinematics. We determined the magnetic field configurations in the corona and interplanetary space, inferred the magnetic connectivity of the spacecraft with the shock surface, and derived the evolution of the shock parameters at the connecting field lines. Results. Remote sensing observations show formation of the coronal shock wave occurring early during the eruption, and its rapid propagation to distant locations. The results of the shock wave modelling show multiple regions where a strong shock has formed and efficient particle acceleration is expected to take place. The pressure/shock wave is magnetically connected to all spacecraft locations before or during the estimated SEP release times. The release of the observed near-relativistic electrons occurs predominantly close to the time when the pressure/shock wave connects to the magnetic field lines or when the shock wave becomes supercritical, whereas the proton release is significantly delayed with respect to the time when the shock wave becomes supercritical, with the only exception being the proton release at the Parker Solar Probe. Conclusions. Our results suggest that the shock wave plays an important role in the spread of SEPs. Supercritical shock regions are connected to most of the spacecraft. The particle increase at Earth, which is barely connected to the wave, also suggests that the cross-field transport cannot be ignored. The release of energetic electrons seems to occur close to the time when the shock wave connects to, or becomes supercritical at, the field lines connecting to the spacecraft. Energetic protons are released with a time-delay relative to the time when the pressure/shock wave connects to the spacecraft locations. We attribute this delay to the time that it takes for the shock wave to accelerate protons efficiently.Peer reviewe

Histopathological Analysis of Skeletal Muscle Biopsy of Patient with Peripheral Arterial Disease before and after Peripheral Blood Stem Cells Intramuscular Injection

© 2016, Springer Science+Business Media New York.Peripheral arterial diseases are characterized by a progressing tissue ischemia which results in the invalidization of patients. The aim of our research was to study the morphological effects of autologous peripheral blood stem cells intramuscular injection into patients with peripheral arterial disease. Peripheral blood stem cells were transplanted intramuscularly into a 48-year-old male patient with peripheral arterial disease stage IIb by Fontaine. The biopsies of his gastrocnemius muscle were taken before the stem cells were transplanted and 3 months after transplantation. These biopsies were stained with H&E and also with antibodies against CD34, myogenin, caspase 3, and bcl-2. Immunohistochemical study results showed an increase of capillary density of 32.7 % (P = 0.005). In muscular biopsies obtained before therapy, we identified single myogenin+ myosatellite cells, while 3 months after transplantation we detected the presence of cells with myogenin-positive nuclei and multinucleated myotubes. We also observed the formation of young myogenin+ muscle fibers with central nuclei. There was no significant difference in the expression of caspase-3 before transplantation and 3 months after transplantation. An increased number of bcl-2+ myosatellite cells, myotubes, and muscle fibers were detected after transplantation. The patient’s ankle-brachial index increased by 13.56 % (0.59 before and 0.67 3 months post transplantation). The patient’s pain-free walking distance by 89.97 % (from 59.56 to 113.77 m). Control arteriograms showed the formation of new collaterals. Transplanted autologous peripheral blood stem cells stimulated the formation of new capillaries, the activation of myosatellite cells and bcl-2 expression in muscle fibers