184 research outputs found
Synchronization, Control and Stability of Fractional Order Hyperchaotic Systems in The Context of The Generalized Memory
In the article offered fractional kinetic model of networks with generalized memory. On the basis of fractional kinetic model network with hyperchaotic systems, embedded in a percolation structure, realized task topologically synchronization. While tracing control and stability. Criterion ndash ldquoproximityrdquo capture average return time Poincare. Shows a visualization of results
Monitoring vibrations and microdisplacement for "pin on disc" tribology studies
The paper studies the example of applying accelerometers to evaluate tribocoupling vibration characteristics and verification methods in the testing system "pin on disc". Microelectromechanical systems (MEMS) intended for operation over a wide static and spectral ranges were applied. Accelerator spatial track recovery was implemented through the double integration algorithm. In the course of the work, the vibrations occurring through the friction between fluorocarbon and brass alloy LS59-1 under the conditions of dry friction were studied
Monitoring vibrations and microdisplacement for "pin on disc" tribology studies
The paper studies the example of applying accelerometers to evaluate tribocoupling vibration characteristics and verification methods in the testing system "pin on disc". Microelectromechanical systems (MEMS) intended for operation over a wide static and spectral ranges were applied. Accelerator spatial track recovery was implemented through the double integration algorithm. In the course of the work, the vibrations occurring through the friction between fluorocarbon and brass alloy LS59-1 under the conditions of dry friction were studied
ESPECIALLY SHARING MELTING HEAT STORAGE SYSTEMS AND ADDITIONAL HEAT REMOVAL
In article are considered various constructive options of devices for cooling of radioelectronic devices working in repeated and short-term modes
Investigation of conduction band structure, electron scattering mechanisms and phase transitions in indium selenide by means of transport measurements under pressure
In this work we report on Hall effect, resistivity and thermopower
measurements in n-type indium selenide at room temperature under either
hydrostatic and quasi-hydrostatic pressure. Up to 40 kbar (= 4 GPa), the
decrease of carrier concentration as the pressure increases is explained
through the existence of a subsidiary minimum in the conduction band. This
minimum shifts towards lower energies under pressure, with a pressure
coefficient of about -105 meV/GPa, and its related impurity level traps
electrons as it reaches the band gap and approaches the Fermi level. The
pressure value at which the electron trapping starts is shown to depend on the
electron concentration at ambient pressure and the dimensionality of the
electron gas. At low pressures the electron mobility increases under pressure
for both 3D and 2D electrons, the increase rate being higher for 2D electrons,
which is shown to be coherent with previous scattering mechanisms models. The
phase transition from the semiconductor layered phase to the metallic sodium
cloride phase is observed as a drop in resistivity around 105 kbar, but above
40 kbar a sharp nonreversible increase of the carrier concentration is
observed, which is attributed to the formation of donor defects as precursors
of the phase transition.Comment: 18 pages, Latex, 10 postscript figure
The Disk Wind in the Young Binaries and the Origin of the Cyclic Activity of Young Stars
We present results of numerical modeling of the cyclic brightness modulation
in the young binary systems with the eccentric orbits and low-mass secondary
components. Brightness variations of the primary is due to the periodical
extinction variations on the line-of-sight caused by the disk wind of the
secondary and a common envelope it produces. A matter distribution in the
envelope has been calculated in the ballistic approach. Calculations showed
that for the young binaries with the elliptic orbits parameters of the
photometric minima (their depth, duration and the shape of light curves) depend
not only on the disk wind parameters and an inclination of the binary orbit to
the line-of-sight but also on the longitude of the periastron. A modulation of
the scattered radiation of the common envelope with a phase of the orbital
period has been investigated in the single scattering approach. It is shown
that an amplitude of the modulation is maximal when the system is seen edge-on
and has also a non-zero value in the binaries observed pole-on. Possible
applications of the theory to the young stellar objects are discussed. In
particular, an attention is payed to a resemblance of the light curves in some
models with light curves of the objects suspected as candidates to FUORs.Comment: 18 pages, 9 figures, accepted by Astronomy Letter
СОЧЕТАНИЕ ТЯЖЕЛОГО ТЕЧЕНИЯ ЯЗВЕННОЙ БОЛЕЗНИ И ГЕМОФИЛИИ В У РЕБЕНКА. КЛИНИЧЕСКОЕ НАБЛЮДЕНИЕ
Gastroduodenal ulcer is less common and milder in children than in adults. Gastroduodenal ulcer complications, such as hemorrhage, penetration etc. are even less common. Recurrent ulcerous defect hemorrhage is a reason to expand diagnostic search and involve various specialists, primarily hematologists, into the diagnosis establishing process. The article presents a clinical case of a child with gastroduodenal ulcer complicated with recurrent hemorrhage not terminated with the standard therapy; thus, additional diagnostic testing was performed. This helped to detect a hematological disease and determine an optimal therapy amount.Язвенная болезнь желудка и двенадцатиперстной кишки у детей встречается реже, чем у взрослых, и отличается более легким течением. Еще реже у детей встречаются осложнения язвенной болезни, такие как кровотечение, пенетрация и др. Рецидивирующие кровотечения из язвенных дефектов являются поводом для расширения диагностического поиска и привлечения к процессу постановки диагноза различных специалистов, в первую очередь гематологов. В статье представлен клинический случай ребенка с язвенной болезнью, осложненной рецидивирующими кровотечениями, которые не купировались при применении стандартной терапии, что послужило причиной для дополнительных диагностических исследований. Это позволило выявить гематологическое заболевание и определить оптимальный объем терапии
K+ channel openers restore verapamil-inhibited lung fluid resolution and transepithelial ion transport
<p>Abstract</p> <p>Background</p> <p>Lung epithelial Na<sup>+ </sup>channels (ENaC) are regulated by cell Ca<sup>2+ </sup>signal, which may contribute to calcium antagonist-induced noncardiogenic lung edema. Although K<sup>+ </sup>channel modulators regulate ENaC activity in normal lungs, the therapeutical relevance and the underlying mechanisms have not been completely explored. We hypothesized that K<sup>+ </sup>channel openers may restore calcium channel blocker-inhibited alveolar fluid clearance (AFC) by up-regulating both apical and basolateral ion transport.</p> <p>Methods</p> <p>Verapamil-induced depression of heterologously expressed human αβγ ENaC in <it>Xenopus </it>oocytes, apical and basolateral ion transport in monolayers of human lung epithelial cells (H441), and <it>in vivo </it>alveolar fluid clearance were measured, respectively, using the two-electrode voltage clamp, Ussing chamber, and BSA protein assays. Ca<sup>2+ </sup>signal in H441 cells was analyzed using Fluo 4AM.</p> <p>Results</p> <p>The rate of <it>in vivo </it>AFC was reduced significantly (40.6 ± 6.3% of control, <it>P </it>< 0.05, n = 12) in mice intratracheally administrated verapamil. K<sub>Ca3.1 </sub>(1-EBIO) and K<sub>ATP </sub>(minoxidil) channel openers significantly recovered AFC. In addition to short-circuit current (Isc) in intact H441 monolayers, both apical and basolateral Isc levels were reduced by verapamil in permeabilized monolayers. Moreover, verapamil significantly altered Ca<sup>2+ </sup>signal evoked by ionomycin in H441 cells. Depletion of cytosolic Ca<sup>2+ </sup>in αβγ ENaC-expressing oocytes completely abolished verapamil-induced inhibition. Intriguingly, K<sub>V </sub>(pyrithione-Na), K <sub>Ca3.1 </sub>(1-EBIO), and K<sub>ATP </sub>(minoxidil) channel openers almost completely restored the verapamil-induced decrease in Isc levels by diversely up-regulating apical and basolateral Na<sup>+ </sup>and K<sup>+ </sup>transport pathways.</p> <p>Conclusions</p> <p>Our observations demonstrate that K<sup>+ </sup>channel openers are capable of rescuing reduced vectorial Na<sup>+ </sup>transport across lung epithelial cells with impaired Ca<sup>2+ </sup>signal.</p
Multi-band analyses of the bright GRB~230812B and the associated SN2023pel
GRB~230812B is a bright and relatively nearby () long gamma-ray
burst that has generated significant interest in the community and therefore
has been subsequently observed over the entire electromagnetic spectrum. We
report over 80 observations in X-ray, ultraviolet, optical, infrared, and
sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for
Multi-messenger Addicts) network of observatories and from observational
partners. Adding complementary data from the literature, we then derive
essential physical parameters associated with the ejecta and external
properties (i.e. the geometry and environment) and compare with other analyses
of this event (e.g. Srinivasaragavan et al. 2023). We spectroscopically confirm
the presence of an associated supernova, SN2023pel, and we derive a
photospheric expansion velocity of v 17 km . We
analyze the photometric data first using empirical fits of the flux and then
with full Bayesian Inference. We again strongly establish the presence of a
supernova in the data, with an absolute peak r-band magnitude . We find a flux-stretching factor or relative brightness and a time-stretching factor ,
both compared to SN1998bw. Therefore, GRB 230812B appears to have a clear long
GRB-supernova association, as expected in the standard collapsar model.
However, as sometimes found in the afterglow modelling of such long GRBs, our
best fit model favours a very low density environment (). We also find small values for
the jet's core angle and
viewing angle. GRB 230812B/SN2023pel is one of the best characterized
afterglows with a distinctive supernova bump
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