513 research outputs found
Strategy for diagnosis and correction of vaginal dysbiosis in terms of preparation of pregnant for planned cesarean section and prevention of postpartum endometritis.
Clinical features of vaginal dysbiosis as a factor in the high risk of septic complications, especially in pregnant women diagnosed with anaerobic vaginal dysbiosis were examined. Low efficiency of the traditional methods of treating bacterial dysbiosis, a high rate of recurrences and the risk of preterm delivery dictate the need to find alternative methods of treatment and prevention of antenatal and post-natal complications. The widespread introduction of caesarean section into obstetric practice contributed to the reduction of perinatal loss. However, together with the expansion of indications for cesarean section, increase in the frequency and severity of post-natal chronic inflammatory diseases is associated. The number of purulent-inflammatory diseases in the early postoperative period and in the long-term period after C-section is large, reaching 3,3-54,3%. Postpartum period, even in physiological course and particularly in the presence of risk factors is favorable for the development of infectious complications. Almost all the authors identify caesarean section as a significant risk factor for postpartum endometritis, since, making only 10 - 20% of the total number of deliveries, cesarean section causes 80% of all postpartum endometritis. We propose a diagnostic algorithm, drug correction and prevention for this common group of patients
Into the deep: New data on the lipid and fatty acid profile of redfish Sebastes mentella inhabiting different depths in the Irminger Sea
New data on lipid and fatty acid profiles are presented, and the dynamics of the studied components in muscles in the males and females of the beaked redfish, Sebastes mentella, in the depth gradient of the Irminger Sea (North Atlantic) is discussed. The contents of the total lipids (TLs), total phospholipids (PLs), monoacylglycerols (MAGs), diacylglycerols (DAGs), triacylglycerols (TAGs), cholesterol (Chol), Chol esters, non-esterified fatty acids (NEFAs), and wax esters were determined by HPTLC; the phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), and lysophosphatidylcholine (LPC) were determined by HPLC; and fatty acids of total lipids were determined using GC. The Chol esters prevailed in muscles over the storage TAGs, and the wax ester content was high, which is a characteristic trait of vertically migrating species. Specific dynamics in certain PL in redfish were found to be depended on depth, suggesting that PLs are involved in the re-arrangement of the membrane physicochemical state and the maintenance of motor activity under high hydrostatic pressure. The high contents of DHA and EPA were observed in beaked redfish muscles is the species’ characteristic trait. The MUFAs in muscles include dietary markers of zooplankton (copepods)—20:1(n-9) and 22:1(n-11), whose content was found to be lower in fish sampled from greater depth
Enabling propagation of anisotropic polaritons along forbidden directions via a topological transition
Recent discoveries of polaritons in van der Waals (vdW) crystals with
directional in-plane propagation, ultra-low losses, and broad spectral
tunability have opened the door for unprecedented manipulation of the flow of
light at the nanoscale. However, despite their extraordinary potential for
nano-optics, these unique polaritons also present an important limitation:
their directional propagation is intrinsically determined by the crystal
structure of the host material, which imposes forbidden directions of
propagation and hinders its control. Here, we theoretically predict and
experimentally demonstrate that directional polaritons (in-plane hyperbolic
phonon polaritons) in a vdW biaxial slab (alpha-phase molybdenum trioxide) can
be steered along previously forbidden directions by inducing an optical
topological transition, which naturally emerges when placing the slab on a
substrate with a given negative permittivity (4H-SiC). Importantly, due to the
low-loss nature of this topological transition, we are able to visualize in
real space exotic intermediate polaritonic states between mutually orthogonal
hyperbolic regimes, which permit to unveil the unique topological origin of the
transition. This work provides new insights into the emergence of low-loss
optical topological transitions in vdW crystals, offering a novel route to
efficiently steer the flow of energy at the nanoscale
Enabling propagation of anisotropic polaritons along forbidden directions via a topological transition
Polaritons with directional in-plane propagation and ultralow losses in van der Waals (vdW) crystals promise unprecedented manipulation of light at the nanoscale. However, these polaritons present a crucial limitation: their directional propagation is intrinsically determined by the crystal structure of the host material, imposing forbidden directions of propagation. Here, we demonstrate that directional polaritons (in-plane hyperbolic phonon polaritons) in a vdW crystal (α-phase molybdenum trioxide) can be directed along forbidden directions by inducing an optical topological transition, which emerges when the slab is placed on a substrate with a given negative permittivity (4H–silicon carbide). By visualizing the transition in real space, we observe exotic polaritonic states between mutually orthogonal hyperbolic regimes, which unveil the topological origin of the transition: a gap opening in the dispersion. This work provides insights into optical topological transitions in vdW crystals, which introduce a route to direct light at the nanoscale
Variational calculations for the hydrogen-antihydrogen system with a mass-scaled Born-Oppenheimer potential
The problem of proton-antiproton motion in the --
system is investigated by means of the variational method. We introduce a
modified nuclear interaction through mass-scaling of the Born-Oppenheimer
potential. This improved treatment of the interaction includes the nondivergent
part of the otherwise divergent adiabatic correction and shows the correct
threshold behavior.
Using this potential we calculate the vibrational energy levels with angular
momentum 0 and 1 and the corresponding nuclear wave functions, as well as the
S-wave scattering length. We obtain a full set of all bound states together
with a large number of discretized continuum states that might be utilized in
variational four-body calculations. The results of our calculations gives an
indication of resonance states in the hydrogen-antihydrogen system
Focusing of in-plane hyperbolic polaritons in van der Waals crystals with tailored infrared nanoantennas
Phonon polaritons (PhPs),light coupled to lattice vibrations,with in-plane
hyperbolic dispersion exhibit ray-like propagation with large wavevectors and
enhanced density of optical states along certain directions on a surface. As
such, they have raised a surge of interest as they promise unprecedented
possibilities for the manipulation of infrared light with planar circuitry and
at the nanoscale. Here, we demonstrate, for the first time, the focusing of
in-plane hyperbolic PhPs propagating along thin slabs of MoO3. To that end, we
developed metallic nanoantennas of convex geometries for both the efficient
launching and focusing of the polaritons. Remarkably, the foci obtained exhibit
enhanced near-field confinement and absorption compared to foci produced by
in-plane isotropic PhPs. More intriguingly, foci sizes as small as lamdap/5
=lamda0/50 were achieved (lamdap is the polariton wavelength and lamda0 the
photon wavelength). Focusing of in-plane hyperbolic polaritons introduces a
first and most basic building block developing planar polariton optics
utilizing in-plane anisotropic van der Waals materials and metasurfaces
Development of a PbWO4 Detector for Single-Shot Positron Annihilation Lifetime Spectroscopy at the GBAR Experiment
We have developed a PbWO4 (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium (o-Ps) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of o-Ps to reduce part of the uncertainties of the measurement. These will allow to improve the precision in the measurement of the cross-section for the (anti)hydrogen formation by (anti)proton-positronium charge exchange and to optimize the yield of antihydrogen ion which is an essential parameter in the GBAR experiment
Estimation of the main dimensions of the traction permanent magnet-assisted synchronous reluctance motor
Goal. The goal of the research is to develop an algorithm for selecting the main dimensions of a traction permanent magnet-assisted synchronous reluctance motor. Methodology. A method for determining the main dimensions of the motor, which combines the analytical selection of stator parameters and numerical field calculations for the selection of rotor parameters. The need to check the mechanical strength of a rotor with permanent NdFeB magnets in flux barriers is shown. Results. The article proposes an algorithm for selecting the main dimensions of a traction permanent magnet-assisted synchronous reluctance motor, which combines analytical expressions for selecting stator parameters and numerical field calculations for selecting rotor parameters. It is determined that analytical methods for calculating the magnetic circuit need to be developed in order to reduce the time to select the main dimensions of the motor. Originality. For the first time the sizes of active parts of the permanent magnet-assisted synchronous reluctance motor with power of 180 kW for the drive of wheels of the trolleybus are defined. Practical significance. As a result of research the sizes of active parts, stator winding data and a design of a rotor of the electric motor are defined. The obtained results can be applied when creating an electric motor for a trolleybus
Оцінка головних розмірів тягового синхронно-реактивного електродвигуна з постійними магнітами
Goal. The goal of the research is to develop an algorithm for selecting the main dimensions of a traction permanent magnet-assisted synchronous reluctance motor. Methodology. A method for determining the main dimensions of the motor, which combines the analytical selection of stator parameters and numerical field calculations for the selection of rotor parameters. The need to check the mechanical strength of a rotor with permanent NdFeB magnets in flux barriers is shown. Results. The article proposes an algorithm for selecting the main dimensions of a traction permanent magnet-assisted synchronous reluctance motor, which combines analytical expressions for selecting stator parameters and numerical field calculations for selecting rotor parameters. It is determined that analytical methods for calculating the magnetic circuit need to be developed in order to reduce the time to select the main dimensions of the motor. Originality. For the first time the sizes of active parts of the permanent magnet-assisted synchronous reluctance motor with power of 180 kW for the drive of wheels of the trolleybus are defined. Practical significance. As a result of research the sizes of active parts, stator winding data and a design of a rotor of the electric motor are defined. The obtained results can be applied when creating an electric motor for a trolleybus.У статті розглянуті питання проектування тягового синхронно-реактивного електродвигуна з постійними магнітами потужністю 180 кВт для приводу коліс тролейбуса. Запропоновано спосіб визначення головних розмірів електродвигуна, який поєднує аналітичний вибір параметрів статора та чисельно-польові розрахунки для вибору параметрів ротора. Показана необхідність перевірки механічної міцності ротора, в якому розташовано постійні магніти NdFeB у потокових бар’єрах. У результаті дослідження визначено розміри активних частин, обмоткові дані статора та конструктив ротора електродвигуна
Endoprosthesis replacement at the treatment of elbow joint defects
Results of 25 total endoprosthesis operations in patients with defects of the elbow joint of various ethiology are analysed. The endoprostheses produced by Endoservis (Russia] and Coоnrad/Mоrrey Zimmer (USA] were used. The technique of operation and postoperative rehabilitation is described in the article. The estimation of results of treatment was performed by «the Estimation of surgery of an elbow» (American Shoulder and Elbow Surgeons (ASES] Assessments; Richards R.R. et al. 1994]. Radiographically the results of treatment were estimated by the method of X-ray stability of the implants by O.A. Kudinov, V.l. Nujdin. The majority of patients undergoing arthroplasty of the elbow joint for its defects were of young age (40-45 years], and that has left its mark on the technology of operation and maintenance of the patients in different periods after surgery. The analysis of results of treatmentfor 1 year until 1-15 years after the operation was carried out. Good and excellent results, were received in 68 %, satisfactory - in 30 %. The unsatisfactory result of endoprosthesis surgery took place in 8 % of operated (2 patients]. It has been established that the endoprosthesis replacement for elbow joint defects in high-tech surgery is definitely an alternative to traditional methods of treatment, and in most cases should be seen as a method of choice for treatment of this disease
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