3,542 research outputs found
Imidazoline receptors agonists: possible mechanisms of endothelioprotection
In this review, the historical, physiological, pathophysiological aspects concerning imidazoline receptor agonists and possible mechanisms for their participation in endothelioprotection were considered. Illuminated the molecular biology of each subtype of imidazoline receptors and their significance in the pharmacological correction of cardiovascular diseas
Evaluation of clinical efficacy and safety of the Ilizarov apparatus for external fixation (literature review)
Purpose A retrospective analysis of clinical efficacy and safety of using the external fixation apparatus of G.A. Ilizarov's design. Materials and methods Analysis and evaluation of clinical data was performed using 107 literary sources. 4.200 clinical cases were studied to evaluate effectiveness, and 6.274 cases to assess safety. Results The analysis revealed a high clinical efficacy of using the Ilizarov apparatus for external fixation (various assemblies) in solving a wide range of practical problems in the field of traumatology and orthopedics. According to the results of the study, its high clinical treatment effectiveness was confirmed both on the use of the method in general (about 95 % of positive outcomes), and in specific nosological groups of patients (not lower than 90 % of positive outcomes). After having assessed the available data on the safety in the application of the Ilizarov apparatus for external fixation (various assemblies), we can conclude that the rates of adverse events, recorded in the literature analyzed, can be considered acceptable. Among all those events, the events classified as adverse effects of the product amounted to 17.03 % (5 ÷ 95 % CI: 16.11 ÷ 17.97 %). © Soldatov Yu.P., Stogov M.V., Ovchinnikov E.N., Gubin A.V., Gorodnova N.V., 2019. © 2019 Russian Ilizarov Scientific Center for Restorative Traumatology and Orthopaedics
Gate-Voltage Studies of Discrete Electronic States in Al Nanoparticles
We have investigated the spectrum of discrete electronic states in single,
nm-scale Al particles incorporated into new tunneling transistors, complete
with a gate electrode. The addition of the gate has allowed (a) measurements of
the electronic spectra for different numbers of electrons in the same particle,
(b) greatly improved resolution and qualitatively new results for spectra
within superconducting particles, and (c) detailed studies of the gate-voltage
dependence of the resonance level widths, which have directly demonstrated the
effects of non-equilibrium excitations.Comment: 4 pages, 7 figure
Shuttle Mechanism for Charge Transfer in Coulomb Blockade Nanostructures
Room-temperature Coulomb blockade of charge transport through composite
nanostructures containing organic inter-links has recently been observed. A
pronounced charging effect in combination with the softness of the molecular
links implies that charge transfer gives rise to a significant deformation of
these structures. For a simple model system containing one nanoscale metallic
cluster connected by molecular links to two bulk metallic electrodes we show
that self-excitation of periodic cluster oscillations in conjunction with
sequential processes of cluster charging and decharging appears for a
sufficiently large bias voltage. This new `electron shuttle' mechanism of
discrete charge transfer gives rise to a current through the nanostructure,
which is proportional to the cluster vibration frequency.Comment: 4 pages, 4 figure
Using artificial intelligence to optimize intermodal networking of organizational agents within the digital economy
The problems of forming a digital economy supersystem have been analyzed by the authors using a key business model of sharing digital assets by organizational agents based on the convergence of telematic, computing and information services with the final output of a complex of managed digital objects to a new quality control based on the M2M principle integration. The integration of standardized network infrastructures allows the transformation of traditional linear-hierarchical chains of management transactions in a network of transactions of digital objects that perform intelligent interaction without human intervention through IP-like connections. The introduction of universal shells of any business process from the processing of primary data to processing in the deep region with the use of advanced multi-agent optimization algorithms of the next [after 3G] generation [based on 4G, 5G, etc.], implemented within the electronic micro-, meso-and macrocontent allows us to ensure the stability of the super system within the optimal values of the activities of controlled digital objects due to the increased possibilities of observation and control
Tunneling through a multigrain system: deducing the sample topology from the nonlinear conductance
We study a current transport through a system of a few grains connected with
tunneling links. The exact solution is given for an arbitrarily connected
double-grain system with a shared gate in the framework of the orthodox model.
The obtained result is generalized for multigrain systems with strongly
different tunneling resistances. We analyse the large-scale nonlinear
conductance and demonstrate how the sample topology can be unambiguously
deduced from the spectroscopy pattern (differential conductance versus
gate-bias plot). We present experimental data for a multigrain sample and
reconstruct the sample topology. A simple selection rule is formulated to
distinguish samples with spectral patterns free from spurious disturbance
caused by recharging of some grains nearby. As an example, we demonstrate
experimental data with additional peaks in the spectroscopy pattern, which can
not be attributed to coupling to additional grains. The described approach can
be used to judge the sample topology when it is not guaranteed by fabrication
and direct imaging is not possible.Comment: 13 pages (including 8 figures
Puzzles of Dark Matter - More Light on Dark Atoms?
Positive results of dark matter searches in experiments DAMA/NaI and
DAMA/LIBRA confronted with results of other groups can imply nontrivial
particle physics solutions for cosmological dark matter. Stable particles with
charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a
specific nuclear-interacting form of dark matter. Slowed down in the
terrestrial matter, OHe is elusive for direct methods of underground Dark
matter detection using its nuclear recoil. However, low energy binding of OHe
with sodium nuclei can lead to annual variations of energy release from OHe
radiative capture in the interval of energy 2-4 keV in DAMA/NaI and DAMA/LIBRA
experiments. At nuclear parameters, reproducing DAMA results, the energy
release predicted for detectors with chemical content other than NaI differ in
the most cases from the one in DAMA detector. Moreover there is no bound
systems of OHe with light and heavy nuclei, so that there is no radiative
capture of OHe in detectors with xenon or helium content. Due to dipole Coulomb
barrier, transitions to more energetic levels of Na+OHe system with much higher
energy release are suppressed in the correspondence with the results of DAMA
experiments. The proposed explanation inevitably leads to prediction of
abundance of anomalous Na, corresponding to the signal, observed by DAMA.Comment: Contribution to Proceedings of XIII Bled Workshop "What Comes beyond
the Standard Model?
A Molecular Platinum Cluster Junction: A Single-Molecule Switch
We present a theoretical study of the electronic transport through
single-molecule junctions incorporating a Pt6 metal cluster bound within an
organic framework. We show that the insertion of this molecule between a pair
of electrodes leads to a fully atomically engineered nano-metallic device with
high conductance at the Fermi level and two sequential high on/off switching
states. The origin of this property can be traced back to the existence of a
HOMO which consists of two degenerate and asymmetric orbitals, lying close in
energy to the Fermi level of the metallic leads. Their degeneracy is broken
when the molecule is contacted to the leads, giving rise to two resonances
which become pinned close to the Fermi level and display destructive
interference.Comment: 4 pages, 4 figures. Reprinted (adapted) with permission from J. Am.
Chem. Soc., 2013, 135 (6), 2052. Copyright 2013 American Chemical Societ
Adaptive pseudolinear compensators of dynamic characteristics of automatic control systems
Adaptive pseudolinear gain and phase compensators of dynamic characteristics of automatic control systems are suggested. The automatic control system performance with adaptive compensators has been explored. The efficiency of pseudolinear adaptive compensators in the automatic control systems with time-varying parameters has been demonstrated
Deuteron and antideuteron production in Au+Au collisions at sqrt(s_NN)=200 GeV
The production of deuterons and antideuterons in the transverse momentum
range 1.1 < p_T < 4.3 GeV/c at mid-rapidity in Au + Au collisions at
sqrt(s_NN)=200 GeV has been studied by the PHENIX experiment at RHIC. A
coalescence analysis comparing the deuteron and antideuteron spectra with those
of protons and antiprotons, has been performed. The coalescence probability is
equal for both deuterons and antideuterons and increases as a function of p_T,
which is consistent with an expanding collision zone. Comparing (anti)proton
yields p_bar/p = 0.73 +/- 0.01, with (anti)deuteron yields: d_bar/d = 0.47 +/-
0.03, we estimate that n_bar/n = 0.64 +/- 0.04.Comment: 326 authors, 6 pages text, 5 figures, 1 Table. Submitted to PRL.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
- …