Publications by authors named "Rumyantsev V"

An overview of various cell engineering techniques being developed for modern conservative and reconstructive periodontology is presented. The accelerated development of cellular engineering technologies poses to medicine and, in particular, periodontics, the task of early implementation of the results of such experiments into patient management protocols. The main groups of promising techniques that are closest to practical healthcare are: isolation and use of stem cells; synthesis of biologically active (inductive) signaling molecules; development of scaffolds that ensure three-dimensional tissue growth.

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Thin HgCdTe/CdHgTe quantum wells (QWs) grown on alternative GaAs (013) substrates have been recently proposed as a material for coherent emitters in the mid-IR region. In this work, we develop a technological process for the fabrication of ridge microresonators in waveguide heterostructures with multiple HgCdTe QWs via photolithography and ion etching. We process two samples with different ridge heights and analyze their emission spectra measured under optical excitation.

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Objective: Assessment of antibacterial properties of a new intracanal paste based on calcium hydroxocuprate (CHC) and silver nanoparticles hydrosol for passive root impregnation.

Material And Methods: The study included 55 teeth with 69 root canals belonging patients with chronic apical periodontitis. The main group, including 44 root canals, was filled with a new paste based on CHC and silver nanoparticles for 7 days after preparation and irrigation.

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Rectal cancer occupies the leading position among cancers, and incidence of locally advanced recurrences is still high despite comprehensive treatment. Combined resections are usually associated with high perioperative risks. These procedures are technically complex interventions requiring further improvement.

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HgCdTe-based heterostructures with quantum wells (QWs) are a promising material for semiconductor lasers in the atmospheric transparency window (3-5 μm) thanks to the possibility of suppressing Auger recombination due to the no-parabolic law of carrier dispersion. In this work, we analyze the thresholds of stimulated emission (SE) under optical pumping from heterostructures with a different number of QWs in the active region of the structure. Total losses in structures are determined from the comparison of thresholds for the different number of QWs in the active region.

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Heterostructures with thin Hg(Cd)Te/CdHgTe quantum wells (QWs) are attractive for the development of mid-infrared interband lasers. Of particular interest are room-temperature operating emitters for the short-wavelength infrared range (SWIR, typically defined as 1.7-3 μm).

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The technology of augmented and mixed reality (AR/MR) is useful in various areas of modern surgery. We considered the use of augmented and mixed reality technologies as a method of preoperative planning and intraoperative navigation in abdominal cancer patients. Practical use of AM/MR raises a range questions, which demand suitable solutions.

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The SARS-CoV-2 pandemic is a big challenge for humanity. The COVID-19 severity differs significantly from patient to patient, and it is important to study the factors protecting from severe forms of the disease. Respiratory microbiota may influence the patient's susceptibility to infection and disease severity due to its ability to modulate the immune system response of the host organism.

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HgTe/CdHgTe quantum well (QW) heterostructures have attracted a lot of interest recently due to insights they provided towards the physics of topological insulators and massless Dirac fermions. Our work focuses on HgCdTe QWs with the energy spectrum close to the graphene-like relativistic dispersion that is supposed to suppress the non-radiative Auger recombination. We combine various methods such as photoconductivity, photoluminescence and magneto-optical measurements as well as transmission electron microscopy to retrofit growth parameters in multi-QW waveguide structures, designed for long wavelengths lasing in the range of 10-22 μm.

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Was to study the promising areas for using nanotechnologies in dentistry, existing methods of diagnostics, treatment and prevention of the dental diseases based on the properties of nanoparticles, to review the scientific literature devoted to this problem. In this literature review we use 86 sources: 1 Russian and 85 foreign articles. Analyzed articles were published within the last 5 years.

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International Scientific Optical Network (ISON) is an open international voluntary project specializing in observations of the near-Earth space objects. Observatories collaborating with ISON provide the global coverage and successfully combine the observations of the space debris and asteroids. The network includes more than 50 telescopes of 27 observatories in 15 countries and has been working since 2005.

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We calculate the threshold energies of Auger recombination in the HgTe/CdHgTe quantum well heterostructures with the bandgap in the 30-70 meV range. It is shown that there is a maximum in the temperature dependence of the threshold energy for Auger process involving two electrons and a hole. For Auger process involving two holes and an electron, in which the hole is in the second valence subband in the final state, the threshold energy decreases down to zero and then increases steeply as temperature grows.

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Radiative recombination is studied in CdHgTe/HgTe QWs with bandgap in the 40-140 meV range using four-band Kane model. Calculated radiative lifetimes agree well with the photoconductivity kinetics measurements. We show that the side maxima in the valence band hinder the radiative recombination at high carrier concentrations and discuss how to overcome this effect for the development of long-wavelength lasers.

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We report stimulated emission in the 2.8-3.5 μm wavelength range from HgTe/CdHgTe quantum well (QW) heterostructures at temperatures available with thermoelectric cooling.

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Unlabelled: The aim was to investigate the acid-base balance in the mouth and assess the risk of dental disease in practically healthy persons depending on the habitual diet.

Materials And Methods: The study involved 162 people, divided into three groups: with a mixed diet, with protein foods of animal origin and vegetarians. There were studied the pH value of oral fluid, dental, lingual plaque at stimulation with sucrose and urea.

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We study localized photonic excitations in a quasi-two-dimensional non-ideal binary microcavity lattice with use of the virtual crystal approximation. The effect of point defects (vacancies) on the excitation spectrum is investigated by numerical modelling. We obtain the dispersion and the energy gap of the electromagnetic excitations which may be considered as Frenkel exciton-like quasiparticles and analyze the dependence of their density of states on the defect concentrations in a microcavity supercrystal.

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This multiple-dose Phase I/II study provided pharmacodynamics and pharmacokinetics data on the therapeutic benefit of ferric carboxymaltose (FCM, Ferinject) and evaluated the safety and tolerability of this intravenous (i.v.) iron preparation.

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High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute.

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High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute.

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Peculiarities of scattering of TM-polarized light wave by a diamond-like crystalline nano-layer are studied. They are due to specific dispersion of n-phonon polaritons localized in the layer. The IR polaritons discussed here (relating to diamond and Si crystals which are nonpolar materials) will only appear if some of the vibration modes become polar, e.

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Background: Mesalazine as the treatment standard for ulcerative colitis can be applied in different galenical preparations.

Aim: A novel formulation of mesalazine pellets with delayed and prolonged release characteristics was compared with conventional Eudragit L-coated tablets. Furthermore, the effect of mesalazine dose escalation on nonresponders was evaluated in both treatment groups.

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The effect of 7-d head-down tilt (-15 degrees) and decompression of various body parts (lower body--LBNP, upper body in the area of the hydrostatically indifferent point--UBNP, and local negative pressure applied to both calves--LNP) on central circulation was investigated on eight healthy test subjects who, for 10 d, had catheters (Swan-Ganz) implanted into the pulmonary and radial arteries. It was shown that, when calculated by square centimeter of the decompression area, the effect of UBNP on central venous pressure (CVP) and pulmonary artery pressure (PAP) was 3-4 times greater than that of LBNP or LNP. This indicates a high sensitivity of this body part to the exposure.

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