[Artificial ventilation in patients with stroke: main results of the Russian multicenter observational clinical trial RETAS].

Objective: To analyze the relationship between the characteristics of respiratory support (RS) for patients with stroke and clinical factors with the number and structure of complications, deaths, and length of stay in the intensive care unit (ICU) and duration of artificial pulmonary ventilation (ALV).

Material And Methods: The Russian multicenter observational clinical study «Respiratory Therapy for Acute Stroke» (RETAS) that enrolled 1289 patients with stroke requiring RS was conducted under the auspices of the All-Russian public organization «Federation of Anesthesiologists and Resuscitators». Indications for ALV, the use of hyperventilation, the maximum level of positive end-expiratory pressure, starting modes of mechanical ventilation, timing of tracheostomy, the incidence of protein-energy malnutrition (PEM) and infectious complications were analyzed.

Nonlinearity vs nonlocality with emphasis on bandwidth broadening in semiconductor-based 1d metamaterials.

The physics of nonlinear optical materials is incredibly versatile, with the design of novel materials and structures offering numerous degrees of freedom. Nevertheless, weak inherent nonlinearity of conventional optical materials continues to hinder the progress of a number of important applications. In this study, we delve into the realm of broadband enhancement of nonlinearity within one-dimensional (1d) plasmonic metamaterials, exploring its intricate connection with nonlocality.

Unveiling Influence of Dielectric Losses on the Localized Surface Plasmon Resonance in (Al,Ga)As:Sb Metamaterials.

We perform numerical modeling of the optical absorption spectra of metamaterials composed of systems of semimetal antimony nanoparticles embedded into AlxGa1-xAs semiconductor matrices. We reveal a localized surface plasmon resonance (LSPR) in these metamaterials, which results in a strong optical extinction band below, near, or above the direct band gap of the semiconductor matrices, depending on the chemical composition of the solid solutions. We elucidate the role of dielectric losses in AlxGa1-xAs, which impact the LSPR and cause non-plasmonic optical absorption.

Quantum-Size Effects in Ultra-Thin Gold Films on Pt(111) Surface.

We calculate, within the density-functional theory, the atomic and electronic structure of the clean Pt(111) and Au(111) surfaces and the ML-Au/Pt(111) systems with varying from one to three. The effect of the spin-orbital interaction was taken into account. Several new electronic states with strong localization in the surface region were found and discussed in the case of clean surfaces.

Plasmon Resonance in a System of Bi Nanoparticles Embedded into (Al,Ga)As Matrix.

We reveal the feasibility of the localized surface plasmon resonance in a system of Bi nanoparticles embedded into an AlxGa1-xAs semiconductor matrix. With an ab initio determined dielectric function for bismuth and well-known dielectric properties of AlxGa1-xAs solid solution, we performed calculations of the optical extinction spectra for such metamaterial using Mie's theory. The calculations demonstrate a strong band of the optical extinction using the localized surface plasmons near a photon energy of 2.

Quantum Plasmonics in Sub-Atom-Thick Optical Slots.

We show using time-dependent density functional theory (TDDFT) that light can be confined into slot waveguide modes residing between individual atomic layers of coinage metals, such as gold. As the top atomic monolayer lifts a few Å off the underlying bulk Au (111), ab initio electronic structure calculations show that for gaps >1.5 Å, visible light squeezes inside the empty slot underneath, giving optical field distributions 2 Å thick, less than the atomic diameter.

Unusual Low-Energy Collective Charge Excitations in High- Cuprate Superconductors.

Despite decades of intensive experimental and theoretical efforts, the physics of cuprate high-temperature superconductors in general, and, in particular, their normal state, is still under debate. Here, we report our investigation of low-energy charge excitations in the normal state. We find that the peculiarities of the electronic band structure at low energies have a profound impact on the nature of the intraband collective modes.

Multipole Excitations and Nonlocality in 1d Plasmonic Nanostructures.

Efficient simulation methods for taking nonlocal effects in nanostructures into account have been developed, but they are usually computationally expensive or provide little insight into underlying physics. A multipolar expansion approach, among others, holds promise to properly describe electromagnetic interactions in complex nanosystems. Conventionally, the electric dipole dominates in plasmonic nanostructures, while higher order multipoles, especially the magnetic dipole, electric quadrupole, magnetic quadrupole, and electric octopole, can be responsible for many optical phenomena.

Localized Surface Plasmon Resonance in Metamaterials Composed of AsSb Semimetal Nanoparticles in AlGaAsSb Semiconductor Matrix.

We analyze the possibility to realize a localized surface plasmon resonance in metamaterials composed of As1-zSbz nanoparticles embedded in an AlxGa1-xAs1-ySby semiconductor matrix. To this end, we perform ab initio calculations of the dielectric function of the As1-zSbz materials. Changing the chemical composition , we trace the evolution of the band structure, dielectric function, and loss function.

Acoustic Plasmons in Nickel and Its Modification upon Hydrogen Uptake.

In this work, we study, in the framework of the ab initio linear-response time-dependent density functional theory, the low-energy collective electronic excitations with characteristic sound-like dispersion, called acoustic plasmons, in bulk ferromagnetic nickel. Since the respective spatial oscillations in slow and fast charge systems involve states with different spins, excitation of such plasmons in nickel should result in the spatial variations in the spin structure as well. We extend our study to NiHx with different hydrogen concentrations .

Dramatic Plasmon Response to the Charge-Density-Wave Gap Development in 1T-TiSe_{2}.

1T-TiSe_{2} is one of the most studied charge density wave (CDW) systems, not only because of its peculiar properties related to the CDW transition, but also due to its status as a promising candidate of exciton insulator signaled by the proposed plasmon softening at the CDW wave vector. Using high-resolution electron energy loss spectroscopy, we report a systematic study of the temperature-dependent plasmon behaviors of 1T-TiSe_{2}. We unambiguously resolve the plasmon from phonon modes, revealing the existence of Landau damping to the plasmon at finite momentums, which does not support the plasmon softening picture for exciton condensation.

Broadening the absorption bandwidth based on heavily doped semiconductor nanostructures.

Broadband light absorption is a basis for the proper functionality of various materials, microstructures, and devices. Despite numerous studies, however, many aspects of broadband absorption remain uncovered. In this paper, we demonstrate an inverse-problem approach to designing nanostructures with a very low optical reflection and high absorption through a frequency band.

Impact of the energy dispersion anisotropy on the plasmonic structure in a two-dimensional electron system.

The effect of the band structure anisotropy (triangular, square, and hexagonal wrapping) on the electronic collective excitations (plasmons) in a two-dimensional electron gas (2DEG) is studied in the framework of the random-phase approximation. We show that the dynamical dielectric response in these systems strongly depends on the direction of the in-plane momentum transfer . The effect is so pronounced that it results in a different number of electronic collective excitations in some regions, both with - and ∼-like energy dispersions.

Screening in Graphene: Response to External Static Electric Field and an Image-Potential Problem.

We present a detailed first-principles investigation of the response of a free-standing graphene sheet to an external perpendicular static electric field . The charge density distribution in the vicinity of the graphene monolayer that is caused by was determined using the pseudopotential density-functional theory approach. Different geometries were considered.

Electronic Temperature and Two-Electron Processes in Overbias Plasmonic Emission from Tunnel Junctions.

The accurate determination of electronic temperatures in metallic nanostructures is essential for many technological applications, like plasmon-enhanced catalysis or lithographic nanofabrication procedures. In this Letter, we demonstrate that the electronic temperature can be accurately measured by the shape of the tunnel electroluminescence emission edge in tunnel plasmonic nanocavities, which follows a universal thermal distribution with the bias voltage as the chemical potential of the photon population. A significant deviation between electronic and lattice temperatures is found below 30 K for tunnel currents larger than 15 nA.

Evidence for a spin acoustic surface plasmon from inelastic atom scattering.

Closed-shell atoms scattered from a metal surface exchange energy and momentum with surface phonons mostly via the interposed surface valence electrons, i.e., via the creation of virtual electron-hole pairs.

Dataset of the abundance and phytoplankton composition in the Barents Sea in summer 2014-2018.

This data article contains data on the abundance, phytoplankton composition, in the Barents Sea in summer 2014-2018, and physical and hydrochemical parameters in summer 2017. The data are based on the samples collected on stations, where blooms were recorded. The physical data included the water temperature, salinity, oxygen concentrations at the surface, and various depths.

Interannual variability of Emiliania huxleyi blooms in the Barents Sea: In situ data 2014-2018.

Using in situ data of 2014-2018, the summers Emiliania huxleyi blooms in the Barents Sea were studied. The blooms were recorded in the upper mixed layer in July and August every year, during which they spread to cover large areas and were associated with Atlantic waters. The E.

[The treatment efficacy of disturbed swallowing function in patients with ischemic stroke and neurogenous dysfagia in the intensive care unit].

Aim: To evaluate the efficacy of the training method of rehabilitation of patients with neurogenic dysphagia in ischemic stroke carried out with the use of special nutrient mixtures as part of combination therapy.

Material And Methods: The study included 65 patients (35 men and 30 women, aged 45 to 80 years) with dysphagia in the acute period of ischemic stroke. Thirty patients were treated with special binding compounds as part of a combination therapy.

Drivers of phytoplankton blooms in the northeastern Black Sea.

In order to understand of the processes controlling phytoplankton successions in the NE Black Sea, long-term data series are needed. We compiled 15 years (2002-2017) of measurements from which the existence emerges of a tight link between phytoplankton species dominance and nutrients concentrations. The latter is strongly influenced by wind direction.

Modification of a Shockley-Type Surface State on Pt(111) upon Deposition of Gold Thin Layers.

We present a first-principles fully-relativistic study of surface and interface states in the one monolayer (ML) Au/Pt(111) heterostructures. The modification of an unoccupied s - p -type surface state existing on a Pt(111) surface at the surface Brillouin zone center upon deposition of a few atomic Au layers is investigated. In particular, we find that the transformation process of such a surface state upon variation of the Au adlayer thickness crucially depends on the nature of the relevant quantum state in the adsorbate.

Real-Time Observation of Phonon-Mediated σ-π Interband Scattering in MgB_{2}.

In systems having an anisotropic electronic structure, such as the layered materials graphite, graphene, and cuprates, impulsive light excitation can coherently stimulate specific bosonic modes, with exotic consequences for the emergent electronic properties. Here we show that the population of E_{2g} phonons in the multiband superconductor MgB_{2} can be selectively enhanced by femtosecond laser pulses, leading to a transient control of the number of carriers in the σ-electronic subsystem. The nonequilibrium evolution of the material optical constants is followed in the spectral region sensitive to both the a- and c-axis plasma frequencies and modeled theoretically, revealing the details of the σ-π interband scattering mechanism in MgB_{2}.

Angular momentum-induced delays in solid-state photoemission enhanced by intra-atomic interactions.

Attosecond time-resolved photoemission spectroscopy reveals that photoemission from solids is not yet fully understood. The relative emission delays between four photoemission channels measured for the van der Waals crystal tungsten diselenide (WSe) can only be explained by accounting for both propagation and intra-atomic delays. The intra-atomic delay depends on the angular momentum of the initial localized state and is determined by intra-atomic interactions.

Odd-frequency superconductivity induced in topological insulators with and without hexagonal warping.

We study the effect of the Fermi surface anisotropy on the odd-frequency spin-triplet pairing component of the induced pair potential. We consider a superconductor/ ferromagnetic insulator (S/FI) hybrid structure formed on the 3D topological insulator (TI) surface. In this case three ingredients ensure the possibility of the odd-frequency pairing: (1) the topological surface states, (2) the induced pair potential, and (3) the magnetic moment of a nearby ferromagnetic insulator.

On the stability of the electronic system in transition metal dichalcogenides.

Based on first-principles calculations, we prove that the origin of charge-density wave formation in metallic layered transition metal dichalcogenides (TMDC) is not due to an electronic effect, like the Fermi surface (FS) nesting, as it had been proposed. In particular, we consider NbSe2, NbS2, TaSe2, and TaS2 as representative examples of 2H-TMDC polytypes. Our main result consists that explicit inclusion of the matrix elements in first-principles calculations of the electron susceptibility [Formula: see text] removes, due to strong momentum dependence of the matrix elements, almost all the information about the FS topologies in the resulting [Formula: see text].