[Study of the resistome of human microbial communities using a targeted panel of antibiotic resistance genes in COVID-19 patients].

AIM: To study overall drug resistance genes (resistome) in the human gut microbiome and the changes in these genes during COVID-19 in-hospital therapy. MATERIALS AND METHODS: A single-center retrospective cohort study was conducted. Only cases with laboratory-confirmed SARS-CoV-2 RNA using polymerase chain reaction in oro-/nasopharyngeal swab samples were subject to analysis. The patients with a documented history of or current comorbidities of the hepatobiliary system, malignant neoplasms of any localization, systemic and autoimmune diseases, as well as pregnant women were excluded. Feces were collected from all study subjects for subsequent metagenomic sequencing. The final cohort was divided into two groups depending on the disease severity: mild (group 1) and severe (group 2). Within group 2, five subgroups were formed, depending on the use of antibacterial drugs (ABD): group 2A (receiving ABD), group 2AC (receiving ABD before hospitalization), group 2AD (receiving ABD during hospitalization), group 2AE (receiving ABD during and before hospitalization), group 2B (not receiving ABD). RESULTS: The median number of antibiotic resistance (ABR) genes (cumulative at all time points) was significantly higher in the group of patients treated with ABD: 81.0 (95% CI 73.8-84.5) vs. 51.0 (95% CI 31.1-68.4). In the group of patients treated with ABD (2A), the average number of multidrug resistance genes (efflux systems) was significantly higher than in controls (group 2B): 47.0 (95% CI 46.0-51.2) vs. 21.5 (95% CI 7.0-43.9). Patients with severe coronavirus infection tended to have a higher median number of ABR genes but without statistical significance. Patients in the severe COVID-19 group who did not receive ABD before and during hospitalization also had more resistance genes than the patients in the comparison group. CONCLUSION: This study demonstrated that fewer ABR genes were identified in the group with a milder disease than in the group with a more severe disease associated with more ABR genes, with the following five being the most common: SULI, MSRC, ACRE, EFMA, SAT.

Hot-electron preheat and mitigation in polar-direct-drive experiments at the National Ignition Facility.

Target preheat by superthermal electrons from laser-plasma instabilities is a major obstacle to achieving thermonuclear ignition via direct-drive inertial confinement fusion at the National Ignition Facility (NIF). Polar-direct-drive surrogate plastic implosion experiments were performed on the NIF to quantify preheat levels at an ignition-relevant scale and develop mitigation strategies. The experiments were used to infer the hot-electron temperature, energy fraction, and divergence, and to directly measure the spatial hot-electron energy deposition profile inside the imploding shell. Silicon layers buried in the ablator are shown to mitigate the growth of laser-plasma instabilities and reduce preheat, providing a promising path forward for ignition designs at an on-target intensity of about 10^{15}W/cm^{2}.

[Russian multicenter observational clinical study «Register of respiratory therapy for patients with stroke (RETAS)¼: a comparative analysis of the outcomes of stroke]. / Rossiiskoe mnogotsentrovoe observatsionnoe klinicheskoe issledovanie «Registr respiratornoi terapii u patsientov s ONMK (RETAS)¼: sravnitel'naya kharakteristika iskhodov insul'ta.

OBJECTIVE: To analyze the treatment of patients with severe stroke requiring respiratory support, and identify predictors of death. MATERIAL AND METHODS: A multicenter observational clinical study «REspiratory Therapy for Acute Stroke¼ (RETAS) was conducted under the aegis of the «Federation of Anaesthesiologists and Reanimatologists¼ (FAR). The study involved 14 clinical centers and included 1289 stroke patients with respiratory support. RESULTS: We found that initial hypoxemia in the 28-day period was associated with higher mortality than in absence of hypoxemia (in patients with 20 or more NIHSS scores) (76.22% versus 63.45%, p=0.004). Risk factors for lethal outcome: hyperventilation used to relieve intracranial hypertension compared with group of patients who were not treated with hyperventilation (in patients with 20 or more NIHSS scores) (79.55% versus 72.75%, p=0.0336); volume-controlled ventilation (VC) versus pressure-controlled ventilation (PC) (in patients with 20 or more NIHSS scores) (p<0.001); use of clinical methods for monitoring ICP in comparison with instrumental ones (87.64% versus 62.33%, p<0.001). It has been proved that the absence of nutritional insufficiency in patients with stroke is associated with a higher probability of a positive outcome (GOS 4 and 5) in comparison with patients with signs of nutritional insufficiency, for the group with NIHSS less than 14 points (p<0.001). CONCLUSIONS: A group of factors associated with a deterioration in the prognosis of outcomes in patients with stroke who are undergoing ventilation has been identified: hypoxemia at the start of respiratory support, lack of instrumental monitoring of ICP, the use of hyperventilation to correct ICP, ventilation with volume control (VC), as well as the presence of nutritional insufficiency.

Direct Measurements of DT Fuel Preheat from Hot Electrons in Direct-Drive Inertial Confinement Fusion.

Hot electrons generated by laser-plasma instabilities degrade the performance of laser-fusion implosions by preheating the DT fuel and reducing core compression. The hot-electron energy deposition in the DT fuel has been directly measured for the first time by comparing the hard x-ray signals between DT-layered and mass-equivalent ablator-only implosions. The electron energy deposition profile in the fuel is inferred through dedicated experiments using Cu-doped payloads of varying thickness. The measured preheat energy accurately explains the areal-density degradation observed in many OMEGA implosions. This technique can be used to assess the viability of the direct-drive approach to laser fusion with respect to the scaling of hot-electron preheat with laser energy.

Analysis of the He-, Ar- and Kr-broadening coefficients of water vapor transitions in a wide spectral region.

An analysis of the measured He-, Ar- and Kr- broadening coefficients γ for 1575 water vapor transitions of 27 vibrational bands belonging to the 0.6-11,200 cm-1 spectral region is performed using an empirical function that contains adjustable parameters. A universal function is detected during the analysis. This function depends on the parameters that are common for all perturbers A = (He, Ar or Kr). A universal function multiplied by one additional parameter x20(A) determines the broadening coefficients γ(A) for each perturber A = (He, Ar or Kr).Two fitting procedures are used. The first considers the fit of measured γ(exp) for individual rotational branches while the other considers the global fit of all 1575 measured γ(exp). In the second procedure, ratios of γ(Kr)/γ(He) = 2.543 ± 0.040 and γ(Kr)/γ(Ar) = 1.252 ± 0.036 are found. The coefficients derived from the fitted parameters are compared statistically to measured coefficients.

Direct-drive laser fusion: status, plans and future.

Laser-direct drive (LDD), along with laser indirect (X-ray) drive (LID) and magnetic drive with pulsed power, is one of the three viable inertial confinement fusion approaches to achieving fusion ignition and gain in the laboratory. The LDD programme is primarily being executed at both the Omega Laser Facility at the Laboratory for Laser Energetics and at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. LDD research at Omega includes cryogenic implosions, fundamental physics including material properties, hydrodynamics and laser-plasma interaction physics. LDD research on the NIF is focused on energy coupling and laser-plasma interactions physics at ignition-scale plasmas. Limited implosions on the NIF in the 'polar-drive' configuration, where the irradiation geometry is configured for LID, are also a feature of LDD research. The ability to conduct research over a large range of energy, power and scale size using both Omega and the NIF is a major positive aspect of LDD research that reduces the risk in scaling from OMEGA to megajoule-class lasers. The paper will summarize the present status of LDD research and plans for the future with the goal of ultimately achieving a burning plasma in the laboratory. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.

Geometrical-optics computer model of metal-knitted mesh for calculations of solar pressure on space deployable antenna reflectors.

A novel computer 3D model is presented for calculations of optical parameters (transmittance, reflectance, and absorbance) of a metal-knitted mesh textile as a structural element of deployable antenna reflectors for space satellites. The model is based on geometrical-optics ray tracing upon diffuse scattering of a broadband light source (Sun) at a complex knitted mesh structure with different inclinations to the radiative source. The proposed computer model is built for the special type of metal-wire textile (two-bar large void tricot) possessing extremely high transmittance and is verified by comparison with the experimental measurements of light scattering parameters of real antenna mesh samples of data-relaying satellites (Russian series "Loutch"). The model is used for calculations of solar radiation pressure exerted on a knitted mesh antenna reflector and gives the maximal pressure value of about 0.28 µN/m2.

Theory and measurements of convective Raman side scatter in inertial confinement fusion experiments.

Raman side scatter, whereby scattered light is resonant while propagating perpendicularly to a density gradient in a plasma, was identified experimentally in planar-target experiments at the National Ignition Facility at intensities orders of magnitudes below the threshold for absolute instability. We have derived a new theoretical description of convective Raman side scatter below the absolute threshold, validated by numerical simulations. We show that inertial confinement fusion experiments at full ignition scale, i.e., with mm-scale spot sizes and density scale lengths, are prone to increased coupling losses from Raman side scatter as the instability can extend from the absolute regime near the quarter-critical density to the convective regime at lower electron densities.

Tripled yield in direct-drive laser fusion through statistical modelling.

Focusing laser light onto a very small target can produce the conditions for laboratory-scale nuclear fusion of hydrogen isotopes. The lack of accurate predictive models, which are essential for the design of high-performance laser-fusion experiments, is a major obstacle to achieving thermonuclear ignition. Here we report a statistical approach that was used to design and quantitatively predict the results of implosions of solid deuterium-tritium targets carried out with the 30-kilojoule OMEGA laser system, leading to tripling of the fusion yield to its highest value so far for direct-drive laser fusion. When scaled to the laser energies of the National Ignition Facility (1.9 megajoules), these targets are predicted to produce a fusion energy output of about 500 kilojoules-several times larger than the fusion yields currently achieved at that facility. This approach could guide the exploration of the vast parameter space of thermonuclear ignition conditions and enhance our understanding of laser-fusion physics.

Study of the H2O dipole moment and polarisability vibrational dependence by the analysis of rovibrational line shifts.

The study of the H2O dipole moment µ and polarisability α vibrational dependence is based on the comparison of experimental and calculated line shifts induced by argon, nitrogen, and air pressure in different H2O vibrational bands. Obtained dependence α on the stretching vibrations is in good agreement with the existing ab initio calculations in the literature, but the dependence α on the bending vibration is quite different. To clarify the dependence of µ and α on the bending vibration, the shifts of selected H2O lines of the 4ν2, 5ν2, and 6ν2 bands induced by argon, hydrogen and helium pressure are measured with the help of a Bruker IFS HR 125 spectrometer at room temperature with a spectral resolution of 0.01 cm-1. The comparison of experimental and calculated results with different values of µ and α line shifts is given.

Readout models for BaFBr0.85I0.15:Eu image plates.

The linearity of the photostimulated luminescence process makes repeated image-plate scanning a viable technique to extract a more dynamic range. In order to obtain a response estimate, two semi-empirical models for the readout fading of an image plate are introduced; they relate the depth distribution of activated photostimulated luminescence centers within an image plate to the recorded signal. Model parameters are estimated from image-plate scan series with BAS-MS image plates and the Typhoon FLA 7000 scanner for the hard x-ray image-plate diagnostic over a collection of experiments providing x-ray energy spectra whose approximate shape is a double exponential.

Origins and Scaling of Hot-Electron Preheat in Ignition-Scale Direct-Drive Inertial Confinement Fusion Experiments.

Planar laser-plasma interaction (LPI) experiments at the National Ignition Facility (NIF) have allowed access for the first time to regimes of electron density scale length (∼500 to 700 µm), electron temperature (∼3 to 5 keV), and laser intensity (6 to 16×10^{14} W/cm^{2}) that are relevant to direct-drive inertial confinement fusion ignition. Unlike in shorter-scale-length plasmas on OMEGA, scattered-light data on the NIF show that the near-quarter-critical LPI physics is dominated by stimulated Raman scattering (SRS) rather than by two-plasmon decay (TPD). This difference in regime is explained based on absolute SRS and TPD threshold considerations. SRS sidescatter tangential to density contours and other SRS mechanisms are observed. The fraction of laser energy converted to hot electrons is ∼0.7% to 2.9%, consistent with observed levels of SRS. The intensity threshold for hot-electron production is assessed, and the use of a Si ablator slightly increases this threshold from ∼4×10^{14} to ∼6×10^{14} W/cm^{2}. These results have significant implications for mitigation of LPI hot-electron preheat in direct-drive ignition designs.

An algorithm for filtering detector instabilities in search of novel non-exponential decay and in conventional half-life determinations.

Recent reports of Solar modulation of beta-decay have reignited interest in whether or not radioactive half-lives are constants. A numerical approach for filtering instrumental effects on residuals is developed, using correlations with atmospheric conditions recorded while counting 204Tl emissions with a Geiger-Müller counter. Half-life oscillations and detection efficiency oscillations can be separated provided their periods are substantially different. A partial uncertainty budget for the 204Tl half-life shows significant decreases to medium-frequency instabilities correlated with pressure and temperature, which suggests that further development may aid general improvements in half-life determinations.

A high-resolving-power x-ray spectrometer for the OMEGA EP Laser (invited).

A high-resolving-power x-ray spectrometer has been developed for the OMEGA EP Laser System based on a spherically bent Si [220] crystal with a radius of curvature of 330 mm and a Spectral Instruments (SI) 800 Series charge-coupled device. The instrument measures time-integrated x-ray emission spectra in the 7.97- to 8.11-keV range, centered on the Cu Kα1 line. To demonstrate the performance of the spectrometer under high-power conditions, Kα1,2 emission spectra were measured from Cu foils irradiated by the OMEGA EP laser with 100-J, 1-ps pulses at focused intensities above 1018 W/cm2. The ultimate goal is to couple the spectrometer to a picosecond x-ray streak camera and measure temperature-equilibration dynamics inside rapidly heated materials. The plan for these ultrafast streaked x-ray spectroscopy studies is discussed.

[POSITIVE END-EXPIRATORY PRESSURE (PEEP) INFLUENCES ON INTRACRANIAL PRESSURE, SYSTEMIC HEMODYNAMICS AND PULMONARY GAS EXCHANGE IN PATIENTS WITH INTRACRANIAl HEMORRHAGE IN CRITICAL STATE].

Positive end-expiratory pressure is one of the main parameters of respiratory support influencing the gas exchange. However, despite the number ofpositive effects, PEEP can compromise venous outflow from the cranial cavity, increased intracranial pressure, decreased venous return and cardiac output and, consequently, reduced blood pressure and cerebral perfusion. The article presents the results of a survey of 39 patients with intracranial hemorrhage in critical state, undergoing respiratory support with different levels of positive end-expiratory pressure. Increasing of PEEP to 15 cm H2O had no adverse effect on mean arterial pressure, heart rate and cerebral perfusion pressure and led only to an clinical insignificant increase (maximum on 2.4 +/- 5.1 mmHg) in intracranial pressure. The greatest hemodynamic changes were observed with increasing PEEP up to 20 cm H2O in patients with preserved compliance ofthe respiratory system. The instability of cerebral perfusion and intracranial pressure associated with a decrease in cardiac output and preload and the exhaustion of compensatory mechanism of peripheral vascular resistance. High levels of PEEP despite the trend towards Cstat reduction will not lead to an increase in the content of extravascular lung water Thus a gradual increase of PEEP to 15 cm H2O can be safe and effective method of improving pulmonary gas exchange in patients with intracranial hemorrhage in critical state.

[Guidelines for the management of severe traumatic brain injury. Part 3. Surgical management of severe traumatic brain injury (Options)].

Traumatic brain injury (TBI) is one of the main causes of mortality and severe disability in young and middle age patients. Patients with severe TBI, who are in coma, are of particular concern. Adequate diagnosis of primary brain injuries and timely prevention and treatment of secondary injury mechanisms markedly affect the possibility of reducing mortality and severe disability. The present guidelines are based on the authors' experience in developing international and national recommendations for the diagnosis and treatment of mild TBI, penetrating gunshot wounds of the skull and brain, severe TBI, and severe consequences of brain injury, including a vegetative state. In addition, we used the materials of international and national guidelines for the diagnosis, intensive care, and surgical treatment of severe TBI, which were published in recent years. The proposed recommendations for surgical treatment of severe TBI in adults are addressed primarily to neurosurgeons, neurologists, neuroradiologists, anesthesiologists, and intensivists who are routinely involved in treating these patients.

[The use of extra-intracranial microanastomosis in the treatment of cerebral ischemia in patients with nontraumatic subarachnoid hemorrhage]. / Primenenie ekstra-intrakranial'nogo mikroanastomoza v lechenii ishemii golovnogo mozga u bol'nykh s netravmaticheskim subarakhnoidal'nym krovoizliyaniem.

OBJECTIVE: to evaluate the use of extra-intracranial microanastomosis (EICMA) in the treatment of brain ischemia in patients with nontraumatic subarachnoid hemorrhage (SAH). MATERIAL AND METHODS: In the period from 01.01.14 to 01.07.15, there were 229 surgeries for ruptured intracranial aneurysms performed in the urgent surgery unit. Nine patients with marked and widespread angiospasm, subcompensated and decompensated cerebral ischemia underwent the simultaneous clipping of ruptured intracranial aneurysms and EICMA. The age of patients varied from 32 to 52 years (mean 36 years). The severity of patient's state was assessed as III-IV grades on the Hunt and Hess scale before operation. The surgery was performed 1-2 days after admission to the hospital, 1-8 days after the development of SAH. RESULTS AND CONCLUSION: Excellent and good outcome was recorded in 4 patients, severe disability in 3 patients, fatal outcome in 2 patients. The fatal outcome was due to decompensated cerebral ischemia and progressive angiospasm with the high linear blood flow rate and the following reduction in perfusion in the affected hemisphere. The simultaneous clipping of ruptured intracranial aneurysms and EICMA in the acute stage of SAH of patients with subcompensated cerebral ischemia allow to improve treatment RESULTS: This technique is most applicable for patients with proximal angiospasm of M1- and M2-segments of the middle cerebral artery in the first 24 h of the development of a focal neurological deficit supported by the reduction in perfusion in the corresponding vascular area.

[Guidelines for the diagnosis and treatment of severe traumatic brain injury. Part 2. Intensive care and neuromonitoring].

Traumatic brain injury (TBI) is one of the major causes of death and disability in young and middle-aged people. The most problematic group is comprised of patients with severe TBI who are in a coma. The adequate diagnosis of primary brain injuries and timely prevention and treatment of the secondary injury mechanisms largely define the possibility of reducing mortality and severe disabling consequences. When developing these guidelines, we used our experience in the development of international and national recommendations for the diagnosis and treatment of mild traumatic brain injury, penetrating gunshot wounds to the skull and brain, severe traumatic brain injury, and severe consequences of brain injuries, including a vegetative state. In addition, we used international and national guidelines for the diagnosis, intensive care, and surgical treatment of severe traumatic brain injury, which had been published in recent years. The proposed guidelines concern intensive care of severe TBI in adults and are particularly intended for neurosurgeons, neurologists, neuroradiologists, anesthesiologists, and intensivists who are routinely involved in the treatment of these patients.

Two-Plasmon Decay Mitigation in Direct-Drive Inertial-Confinement-Fusion Experiments Using Multilayer Targets.

Multilayer direct-drive inertial-confinement-fusion targets are shown to significantly reduce two-plasmon decay (TPD) driven hot-electron production while maintaining high hydrodynamic efficiency. Implosion experiments on the OMEGA laser used targets with silicon layered between an inner beryllium and outer silicon-doped plastic ablator. A factor-of-5 reduction in hot-electron generation (>50 keV) was observed in the multilayer targets relative to pure CH targets. Three-dimensional simulations of the TPD-driven hot-electron production using a laser-plasma interaction code (lpse) that includes nonlinear and kinetic effects show good agreement with the measurements. The simulations suggest that the reduction in hot-electron production observed in the multilayer targets is primarily caused by increased electron-ion collisional damping.