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The pathologies of parathyroid glands are widespread among endocrine system diseases, excluding diabetes and thyroid pathology. There are only two methods that are used to treat hyperparathyroidisms, such as surgery and conservative therapy. However, transracial thermal destruction methods (ablation) have recently appeared in clinical practice. The methods have good precision and connect with physical phenomena, such as interaction laser, radiofrequency, microwave, and HIFU irradiation with bio substance. The review is dedicated to critically analyze the modern methods for local thermal destruction of the hyper-functioning parathyroid glands. The review includes data from randomized clinical trials from 2012 to 2021. The studies were from Google Scholar and Pubmed with a total number of 1,938 patients (laser ablation ― 216 patients, radiofrequency ablation ― 225, microwave ablation ― 1467, high-density ultrasound ablation ― 30 patients). Recommendations methods of thermal destruction application were obtained during the review. Furthermore, we have designed some algorithms for hyperparathyroidism treatment. Moreover, thermal destruction methods were observed. There are four modern methods of thermal destruction which have been analyzed like alternatives to surgery. Each of them has advantages and disadvantages, its profile of safety and effectiveness. After processing information from a proven database, the most popular among specialists is methods of microwave ablation. However, laser ablation is more effective than other ways.

Probiotics, in particular Lactobacillus (lactic acid bacteria, LAB) strains, are widely used in clinical practice. Despite that these probiotics have GRAS (generally regarded as safe) and qualified presumption of safety (QPS) statuses, the safety of particular strains still needs to be thoroughly studied. The aim of the study was to evaluate the safety of Lact. casei IMV B-7280 strain by investigating toxicity and the effects on gut microbiota in experimental animal model. Male BALB/c mice (7–8 weeks, weight 20–24 g) were treated with amounts of Lact. casei IMV B-7280 strain: 5 × 106, 5 × 108, or 5 × 109 CFU/animal once per day during 7 days, or in the amount of 1 × 1010 CFU/animal once per day during 3 days (most of the proposed probiotic doses for humans—from 108 to 109 CFU) and monitored during 14 days. Blood tests and serum biochemistry were conducted; the cecal content from mice of the experimental and control groups were freshly collected and analyzed. At the end of the experiments (15th day), the presence of LAB in the heart, liver, kidney, and mesenteric lymph nodes and peripheral blood was determined; histology of the brain, liver, heart, fragments of the small and large intestine, and mesenteric lymph nodes was conducted. Survival rate of BALB/c mice treated with Lact. casei IMV B-7280 strain in different concentrations in toxicity experiments during 14 days was 100%. We observed no signs of toxicity as changes in gait, lethargy, sleep, somatomotor activity as well as changes in fur, eyes, skin and mucous membranes, tremors, behavior pattern, convulsions, salivation, diarrhea, and local injuries in mice from all experimental groups. After administration of probiotic strain, the number of opportunistic bacteria in cecal contents, such as Staphylococcus spp., Candida spp., Pseudomonas spp., and total aerobic and optionally anaerobic bacteria decreased compared to controls; the population of beneficial bacteria such as lactobacilli increased in cecal contents of these mice. LAB were not detected in the peripheral blood, heart, liver, kidneys, and mesenteric lymph nodes after administration of this strain to intact mice. Lact. casei IMV B-7280 strain is safe at dose up to 1010 CFU/animal during 3- and 7-day oral administration to mice and has a positive effect on the gut microbiota composition; it could be potentially considered as safe probiotic for humans.

To raise the stimulated Brillouin scattering (SBS) threshold, we have fabricated an optical fibre having a core heavily doped with germanium oxide and displaced from the fibre axis. A method has been proposed for broadening the SBS gain spectrum of the fibre by winding it onto a small-diameter spool, and a broadening of the spectrum by 5.4 dB has been demonstrated, which indicates an increase in SBS threshold by 4.1 dB.

A novel method of stimulated Brillouin scattering (SBS) gain suppression in passive single-mode optical fibers is proposed and experimentally verified. The effect is achieved due to special propagation conditions created for a number of the core-bounded acoustic modes effectively involved in the SBS, such that its gain becomes approximately evenly distributed over a wide spectral range, thereby proportionally reducing its maximum. To verify and investigate this method in depth, single-mode large-mode-area (LMA) fibers with correspondingly optimized acoustic index profiles are fabricated, experimentally tested, and analyzed. Uneven complex doping of the core with two additives, P2O5 and F, forms a high-contrast gradient acoustic index profile while maintaining a quasi-uniform optical refractive index profile. With a contrast of P2O5 of more than 6 mol.%, we achieved 8 dB of SBS suppression over conventional uniformly doped LMA fibers. Moreover, it is shown that more than 10 dB of SBS gain suppression can be achieved if the optimal dopant distribution is realized.

The feasibility of making a wavelength-selective fibre filter using fibre with absorbing rods in its silica cladding has been demonstrated theoretically for the first time. The technique described in this paper is of great practical interest for designing fibre lasers and amplifiers emitting at wavelengths where lasing is impeded by the presence of more energetically favourable radiative transitions in the active medium. In addition, the approach proposed here can be used for stimulated Raman scattering suppression. The unique feature of the fundamental core mode suppression mechanism examined is that there is a (bending) controlled spectral width of a region where excess losses are produced.

We give a review of both our own original scientific results of the development of superconducting receivers for sub-terahertz astronomy and the main leading concepts of the global instrumentation. The analysis of current astronomical problems, the results of microwave astroclimate research, and the development of equipment for sub-terahertz radio astronomy studies justify the need and feasibility of a major infrastructure project in Russia to create a sub-terahertz telescope, as well as to enhance the implementation of the ongoing Millimetron and Suffa projects. The following results are discussed: i) superconducting coherent receivers and broadband subterahertz detectors for space, balloon, and ground-based radio telescopes have been developed and tested; ii) ultrasensitive receiving systems based on tunnel structures such as superconductor-insulator-superconductor (SIS) and superconductor-insulator-normal metal-insulator-superconductor (SINIS) have been created, fabricated, and examined; iii) a receiving array based on SINIS detectors and microwave readout system for such structures has been implemented; iv) methods for manufacturing high-quality tunnel structures Nb/AlOx/Nb and Nb/AlN/NbN based on niobium films with a current density of up to 30 kA/cm(2) have been developed. Receivers operated at 200 to 950 GHz and having a noise temperature only a factor of 2 to 5 higher than the quantum limit have been created and tested.

Modern space-based telescopes operating in the terahertz (THz) spectral range require highly reflecting and cryogenically cooled optics ensuring extremely low noise. The idea of using high-temperature superconductor YBa 2 Cu 3 O 7-δ as a telescope's mirror coating for providing low dissipation and high reflectivity of the surface for the subTHz frequency band has been explored. We are presenting here some results of measurements of the reflection losses in YBa 2 Cu 3 O 7-δ at cryogenic and room temperatures (4.2-300 K) in the frequency band 0.166-0.23 THz. High-accuracy measurements of the absolute value of reflectivity have been performed with the help of the resonance technique. The measured reflection losses in the given frequency band were below 1%. For the same frequency range, these values are well above the reflection losses in normal metals such as copper or aluminum, which are normally used to cover mirrors of telescopes. We, therefore, conclude that the use of high-Tc superconductors YBa 2 Cu 3 O 7-δ as a highly reflecting coating for the THz telescope's mirror is not advisable.

Functional nanocomposites are designed via doping ferroelectric liquid crystal (FLC) matrix by 0.03wt% and 0.1wt% of functionalised multiwall carbon nanotubes (MWCNTs). Mesomorphic, optical, thermo...

A series of heterospin bis-o-semiquinone cobalt, nickel, and copper complexes (4-TEMPO-oxy-3,6-di-tert-butyl-o-benzoquinone derivatives) is synthesized: (DMSO)Cu(4-TEMPO-O-3,6-DBSQ)2 (I), (THF)2Ni(4-TEMPO-O-3,6-DBSQ)2 (II), (Py)2Ni(4-TEMPO-O-3,6-DBSQ)2 (III), and (Py)2Ni(4-TEMPO-O-3,6-DBSQ)2 (IV) (4-TEMPO-O-3,6-DBQ is 4-(3,6-di-tert-butyl-1,2-dioxocyclohexa-3,5-dien-4-yloxy)-2,2,6,6-tetramethylpiperidine-1-oxyl 4-oxy-2,2',6,6'-tetramethylpiperidine-1-oxyl). All complexes are characterized by elemental analysis, IR spectroscopy, magnetochemistry, and EPR. The structure of complex I is determined by X-ray diffraction analysis (CIF file CCDC no. 1882878). The coordination polyhedron of the copper atom in the molecular structure of the Cu(II) bis-o-semiquinone complex with dimethyl sulfoxide (DMSO) is a distorted tetragonal pyramid, whose equatorial plane contains the o-semiquinone ligands, and the DMSO molecule occupies the apical position. The magnetic properties of complexes I–IV are consistent with their compositions and structures. The magnetic behavior of copper complex I and nickel complexes II and III is determined by the balance of two contributions: metal–ligand ferromagnetic exchange interaction and ligand–ligand antiferromagnetic interaction. The temperature dependence of the magnetic moment of cobalt complex IV shows the redox isomeric transformation conjugated with the spin transition, which is characteristic of complexes of this type. No participation of nitroxyl radical centers is observed in intermolecular coordination.

The objective of the study was determining the prophylactic effect of Lactobacillus casei IMV B-7280, L. acidophilus IMV B-7279, L. delbrueckii subsp. bulgaricus IMV B-7281, Bifidobacterium animalis VKL and B. animalis VKB probiotic strains on experimental vaginitis in BALB/c mice induced by Staphylococcus aureus 8325-4. The infection with S. aureus 8325-4 caused an imbalance of microbiota in the vagina and intestine, as evidenced by an increase in the number of opportunistic microorganisms and a decrease in the amount of lactobacilli and bifidobacteria. L. casei IMV B-7280, B. animalis VKL and B. animalis VKB probiotic strains altered the microbiota spectrum of the vagina and intestine of Staphylococcus-infected mice: the amount of Lactobacillus and bifidobacteria increased with the reduction of the number of opportunistic microorganisms. Also under the influence of these strains, the normalization of the microbiota spectrum typical for vagina and intestine was observed in different periods of observation – in the intestines of mice the number of coliform bacteria increased, the number of microscopic fungi, streptococci and staphylococci decreased; in the vagina, the number of coliform bacteria and microscopic fungi decreased, the number of streptococci normalized. Rapid elimination of S. aureus 8325-4 from the vagina and prevention of the spread of infection to the intestine were observed after use of probiotics. Preventive effect of L. acidophilus IMV B-7279 and L. delbrueckii subsp. bulgaricus IMV B-7281 for bacterial vaginitis in mice was less effective. So, the target probiotic strains L. casei IMV B-7280, B. animalis VKL and B. animalis VKB are promising for the creation of highly effective novel probiotic drugs that can be used for directed prevention of infectious and inflammatory diseases of the genitourinary system caused by pathogenic and opportunistic microorganisms.

Ultra-highly-Yb-doped silica-based fibers are of great interest for such application as high-repetition rate mode-lock lasers (for reduction of the cavity length) and single frequency lasers (for increase pump absorption in a short, few cm in length, cavity). Another promising application is high-peak power lasers based on pedestal-supported large-mode-area (LMA) highly-Yb-doped fiber [1] . In the last case utilization of core based on aluminophophosilicate (APS) glass doped with nearly equimolar concentration of Al 2 O 3 and P 2 O 5 is highly desirable. The reason is formation of AlPO 4 join which increase solubility of rare-earth elements and have refractive index close to that of pure silica [2] . Reduction of the core refractive index in this case greatly simplify fabrication of the matched Ge-doped pedestal. At the same time maximum possible Yb 2 O 3 concentration in the core of such fiber is highly desirable to get the shortest possible fiber length.

In this paper we systematically study a limitation for maximum of Yb dopant concentration in silica based fibers. Two the most popular glass matrixes (F-Al2O3-SiO2 and Al2O3-P2O5-SiO2) were thoroughly investigated in this respect. A possibility to introduce ultra-high doping level of Yb2O3 (in excess of 2.5 mol%) with a relatively low optical losses in fibers was demonstrated. At the same time it was investigated that at ultra-high Yb concentration in the fiber core even with maintaining very low background losses (both initial and induced by photodarkening) such a fiber can nearly completely lose its active properties. Optimal glass matrixes and optimal concentration of Yb dopant in the glass core, which allow keep up lasing properties of the developed fibers high, were studied. An ultra-short length fiber amplifier (~3.5 cm) based on the developed Al2O3-P2O5-SiO2 glass core fiber doped with 1.2 mol% of Yb2O3 (Yb ions absorption was about 1000 dB/m at 920 nm) was created.

Here for the first time the technique of the resonant modes coupling is used for spectrally-selective fundamental mode suppression. In our work we considered the fiber design consisting of the low-index core surrounding by the appropriately chosen high-index absorbing rods. Mode suppression in this case happens due to the resonant core mode deformation owing to mode-anticrossing effect and its partial absorption into the rods. According to our calculations it was established that stop-band of the core fundamental mode can be easily adjusted for different practical aims by fiber bending. Furthermore, in the present work we implemented and studied passive fiber with three high-index absorbing rods incorporated into fiber cladding. The Sm was chosen as an absorbing element of the high-index rods.

ART-XC (Astronomical Roentgen Telescope - X-ray Concentrator) is the hard X-ray instrument with grazing incidence imaging optics on board the Spektr-Roentgen-Gamma (SRG) observatory. The SRG observatory is the flagship astrophysical mission of the Russian Federal Space Program, which was successively launched into orbit around the second Lagrangian point (L2) of the Earth-Sun system with a Proton rocket from the Baikonur cosmodrome on 13 July 2019. The ART-XC telescope will provide the first ever true imaging all-sky survey performed with grazing incidence optics in the 4-30 keV energy band and will obtain the deepest and sharpest map of the sky in the energy range of 4-12 keV. Observations performed during the early calibration and performance verification phase as well as during the on-going all-sky survey that started on 12 Dec. 2019 have demonstrated that the in-flight characteristics of the ART-XC telescope are very close to expectations based on the results of ground calibrations. Upon completion of its 4-year all-sky survey, ART-XC is expected to detect ~5000 sources (~3000 active galactic nuclei, including heavily obscured ones, several hundred clusters of galaxies, ~1000 cataclysmic variables and other Galactic sources), and to provide a high-quality map of the Galactic background emission in the 4-12 keV energy band. ART-XC is also well suited for discovering transient X-ray sources. In this paper, we describe the telescope, results of its ground calibrations, major aspects of the mission, the in-flight performance of ART-XC and first scientific results., 19 pages, 30 figures, accepted for publication in Astronomy and Astrophysics

We investigate (both theoretically and experimentally) a method for fundamental mode spectral filtering in single-mode optical fibers using the resonant mode coupling effect. We demonstrate the possibility of controlling the spectral bandwidth of the fundamental mode suppression band through appropriate choice of fiber parameters and fiber bending. The developed technique can be very useful for the design of fiber-based spectral filters (i.e., active fibers with suppression of laser emission at undesirable wavelengths, suppression of stimulated Raman scattering).

The stimulated Brillouin scattering (SBS) is the main power limiting factor in the high-power narrow-line fiber laser circuits. A good way to increase the SBS power-threshold is to reduce its coherent gain, which is directly connected with the width of the Brillouin gain spectrum (BGS). The Brillouin gain peak and the phonons life-time are inversely proportional to the full-width-at-half-maximum of the BGS. The fine structure of the BGS and its ranges are sufficiently affected by parameters of the acoustic waveguide of the fiber. We propose a novel approach for increasing the BGS width and lowering its maximum (related directly to the SBS threshold) for a given optical refractive index profile. The aim of the approach is to maximize both the number and spectral spread of guided acoustic modes, as well as equate the acousto-optic interaction coefficients (acousto-optical overlap integrals) for the maximum possible number of these modes. This is due to the fact that an increase in the number of acoustic modes effectively contributing to the BGS, while preserving the distribution of the optical mode intensity, causes the scattered Stokes optical power to be redistributed accordingly between the corresponding number of Brillouin spectral lines, providing proportional damping of the Brillouin gain. Such an acoustically multimode SBS suppression can be achieved by tailoring a proper radial acoustic refractive index profile which can be fabricated by co-doping of silica with phosphorous oxide and fluorine.

In this paper, we demonstrate the spectrally selective fundamental core mode suppression in single-mode fiber by mode anti-crossing technique. A unique feature of the method proposed in the current work is that the fundamental core mode can have rectangular-like excess loss spectrum with bandwidth controllable by fiber bending. This property made the proposed fiber design to be promising for suppression of lasing at unwanted wavelengths in different fiber lasers and amplifiers.

One of the most frequently utilized liquid crystalline (LC) materials is a rod-like (calamitic) compound 4-cyano-4&prime, pentylbiphenyl (5-CB). The main objective of this work is to enhance its functionality by introducing a photoresponsive diazenyl spacer in the aromatic core and replace the non-chiral pentyl chain with various chiral alkyl carboxylate units. The mesomorphic properties of the prepared materials have been studied using polarizing optical microscopy and differential scanning calorimetry. It has been found that materials with an extended aromatic system possess the liquid crystalline behavior. The studied LC materials have shown mesophases at lower temperatures than previously reported analogous substances. Furthermore, one of them exhibits a chiral orthogonal frustrated twist grain boundary smectic phase, which has not been previously observed for this structural type of materials. We also investigated photoresponse of the mesophases under illumination with UV-light (365 nm) using a polarizing optical microscope. A non-conventional photoresponse of the prepared materials in a crystalline phase is presented and discussed.

The new challenges in the submillimeter astronomy call for the instruments combining high sensitivity and angular resolution, wide field of view, and multiwavelength (multicolor) spectral range. New single dish mm/submm telescopes in Eurasia are in high demand as well as their inclusion in the Event Horizon Telescope (EHT) VLBI network. The astroclimate studies aimed at the selection of the appropriate Eurasian site for a new mm/submm telescope began in 2012. The ESMT concept suggests the construction of three new mm/submm radio telescopes of 15–21 m class to be built in Suffa (Aktashtau), Uzbekistan, in Russia, and in Tibet, China to cover frequency bands up to 230 GHz (Russia), up to 350 GHz (Uzbekistan) and up to 1.5 THz (China). In the ESMT concept European ALMA antennas are taken as a starting point, increased their diameter to 21m, optimized an optical layout and the truss frame, supplemented an active surface and tertiary optics, including adaptive optics. Variants of the ESMT optical layout and tertiary optics are presented, which make it possible to maintain a compact dilution cryostat with KID-array camera in a vertical position during operation of the telescope to ensure its operability. The characteristics of the image quality of ESMT with a large-format KID-array camera in a field of view up to 10′×10′ are estimated. The possibilities of applying active optics with the use of fast holography, precise laser trackers and radars and adaptive optics with a tilted tertiary mirror are considered.

New challenges in submillimeter wave astronomy require instruments with a combination of high sensitivity and angular resolution, wide field of view and multiwave (multicolor) spectral range. New large single mm/submm telescopes are in high demand, as well as their inclusion in the global Event Horizon Telescope (EHT) VLBI network. At the same time, there are no large mm/submm telescopes in Asia at all while appropriate sites exist and their appearance in Asia or Eurasia is long overdue. Kinetic inductance detectors (KID) are ideal for large-format array implementation, which will be necessary for future telescope development. Concept of multicolor subTHz KID-array MUSICAM demo camera and its instrumental testing is given. It allows us to perform some necessary steps toward the creation of the Eurasian SubMillimeter Telescopes (ESMT), which concept and scientific tasks are presented as well.

The order of the SBS gain suppression can be achieved in ordinary step-index single-mode optical fibers due to a wide spectral redistribution and effective equalization of impacts of a relatively large number of acoustic mode fields in the nonlinear Brillouin interaction between them and the fundamental optic mode intensity, using the proper acoustic index profile design.

We present a new design of single-mode Yb-doped fiber for efficient 976 nm lasers. The fiber has 14/45 micron core/cladding diameters. Exploiting of this fiber with a specially designed pump/signal combiner allowed us to realize an all-fiber amplifier with the pump-conversion slope efficiency of 31 % and the output power of 10 W limited only by the available pump power.

In this paper, we present a novel single-mode Yb-doped fiber with 14 µm core and 45 µm cladding diameter. A 976 nm all-fiber high-power amplifier was manufactured based on this fiber. 10-mm-long fiber taper was used to launch the pump light, and guidance of the high NA pump was provided by a glass–air interface. 13 W output power limited only by the available pump power was achieved with 31% slope efficiency.

The control and prediction of soft systems exhibiting self-organization behavior can be realized by different means but still remains a highlighted task. Novel advanced nanocomposite system has been designed by filling of a stretched porous polyethylene (PE) film with pore dimensions of hundreds of nanometers by chiral ferroelectric liquid crystalline (LC) compound possessing polar self-assembling behavior. Lactic acid derivative exhibiting the paraelectric orthogonal smectic A* and the ferroelectric tilted smectic C* phases over a broad temperature range is used as a self-assembling compound. The morphology of nanocomposite film has been checked by Atomic Force Microscopy (AFM). The designed nanocomposite has been studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), small and wide-angle X-ray scattering and broadband dielectric spectroscopy. The effect of a porous PE confinement on self-assembling, structural, and dielectric behavior of the chiral LC compound has been established and discussed. While the mesomorphic and structural properties of the nanocomposite are found not to be much influenced in comparison to that of a pure LC compound, the polar properties have been toughly suppressed by the specific confinement. Nevertheless, the electro-optic switching was clearly observed under applied electric field of low frequency (210 V, 19 Hz). The dielectric spectroscopy and X-ray results reveal that the helical structure of the ferroelectric liquid crystal inside the PE matrix is completely unwound, and the molecules are aligned along stretching direction. Obtained results demonstrate possibilities of using stretched porous polyolefins as promising matrices for the design of new nanocomposites.

Reaction of bis-o-semiquinonato nickel complex (2,2ʹ-dipyridine)Ni(dioxolene)2 (1) (dioxolene here – mono- or double-reduced forms of 3,6-di-tert-butyl-o-benzoquinone) or its cobalt analogue (2,2ʹ-dipyridine)Co(dioxolene)2) with (2,2ʹ-dipyridine)Sn(dioxolene)2 occur through ligands exchange and results in ate-complex [(2,2ʹ-dipyridine)2M(dioxolene)]+ [Sn(dioxolene)3]- (M = Ni (2), Co(3)). According to single crystal x-ray diffraction study both products are isostructural. Geometry of tin anion is intermediate between octahedral and trigonal prism. Analysis of bonds lengths in chelate cycles in tin anion one of dioxolene ligands is semiquinone anion-radical whereas the other two are catecholato-dianions. Geometry of inner coordination core of both cations is close to octahedral. Cobalt being in 3+ oxidation state is connected to catecholato-dianion. Nickel being in 2+ oxidation state is connected to semiquinonato anion-radical. Variable temperature magnetic susceptibility measurements of 2 indicate high spin nickel ferromagnetically coupled with semiquinonato anion-radical connected to it and independent semiquinone coordinated to tin. Cobalt cation is diamagnetic. EPR studies of ate-complex 3 in solution indicate two independent dynamic processes: solvation and migration of unpaired electron between three structurally identical ligands. Rate of this migration depends on solvent and temperature: from slow (CCl4, toluene) to fast (MeOH, CH3CN) in EPR time scale. Solvent role is solvation of the tin anion on one hand and the extent of isolation of ions: from “close pair” in CCl4 to “solvate separated pair” in methanol on the other hand. It is determined by solvent permittivity and dipole moment. Temperature dependence of hyperfine coupling constant with tin magnetic nuclei allowed estimating enthalpy and entropy of solvation. Temperature dependence of EPR spectrum shape together with it simulation allowed to evaluate the rates of spin migration and it activation parameters. In general, the regularities of ate-complex 2 behavior are the same but EPR lines are broader because of presence of high spin nickel and cation polarity effect is less than that in 3 because of smaller charge separation.

Functional organic polymer materials with an ability to change their surface topography in response to external contactless stimuli, like light irradiation, have attracted considerable attention. This work is devoted to the study of contactless control of the surface topography and the formation of the surface features in the amorphousized and liquid crystalline films of two azobenzene-containing polymers. The investigated polymers are side-chain polymethacrylates containing azobenzene chromophores with two lateral methyl substituents in ortho-positions and differing in the length of flexible spacer with six and ten methylene units. Two lateral methyl substituents at the azobenzene chromophore ensure high photoresponses of these polymeric samples in the whole visible spectral range. Irradiation of the polymethacrylate films by focused polarized light of green (532 nm) and red (633 nm) lasers induces a specific photodeformation of the film surface. In the case of the green light formation of circular “craters” with anisotropic borders was found, whereas for the red light highly asymmetric “hills” were observed. The possible mechanisms of the surface topography formation and their features are discussed.

Especially grown crystals (elongated plates) of the complex (1,10-phen)Co(3,6-DBSQ)2 (1) reversibly elastically bend under laser excitation (532 or 808 nm) and/or heating in the temperature interva...

In this paper, we have developed Yb-doped fiber suitable for creation of all-fiber seed laser schemes operating near 977 nm. The fiber was based on a ring-doping design (cladding was partially doped with Yb-ions), which allowed us to fabricate a relatively small core and provide mode field diameter (MFD) of the active fiber comparable with standard fibers (to achieve small splicing losses with commercially available optical fibers) and, simultaneously, increase absorption from the cladding to keep a reasonably high lasing efficiency. So MFDx of the fiber was 12 μm, MFDy was 14 μm. Outer silica cladding of the active fiber was decreased to diameter of 80 μm and a special pump and signal combiner was used to inject pump and signal into the active fiber. Based on the developed Yb-doped fiber an all-fiber polarization maintaining mode-locked laser with central wavelength around 977 nm was demonstrated for the first time. SESAM was used as a saturable absorber. The laser was self-starting for pump powers above 4.6 W, with the output power of 3 mW. The autocorrelation was the best fitted with sech2 profile and pulse duration was estimated to be as long as 9.5 ps. The fundamental cavity frequency corresponded to the pulse repetition rate of 33.532 MHz. Signal-to-noise ratio measured in the radio frequency range was more than 50 dB, the line width was below 1 kHz, which indicate ultimate stability of the fabricated mode-lock laser. acceptedVersion

In the present work, we fabricated Yb-doped hybrid fiber, where unwanted mode suppression was achieved due to selective mode amplification technique. An asymptotically single-mode propagation regime of the realized hybrid fiber was observed in the amplifier scheme even for the case when significant amount of undesirable modes was excited at the fiber input. Measured dispersion of the hybrid fiber at wavelength of 1030 nm was about 70 psec/(nmkm). The realized hybrid fiber was used as nonlinear compressor in all-fiber amplifier scheme. As a seed source we used a commercially available chirped pulse laser (λ~ 1030 nm, a spectrum width was 11 nm and a pulse repetition rate was 42 MHz, pulse duration was adjusted to be of 1 psec by diffraction gratings established on the output of the seed laser). In our experiment to guarantee shorter optimal active fiber length we chose wavelength stabilized pump source at 976 nm. Thus the record high peak power (~10 kW) for all-fiber femtosecond Yb-doped laser schemes was achieved.

This study determines the limiting concentrations of Er2O3 and Yb2O3 in aluminum-phosphorosilicate (APS) glass containing similar concentrations of aluminum and phosphorus, where the signal amplification in the lightguides is still possible. The structural group of AlPO4 is evaluated as a codoping additive to quartz glass, which causes an increase in the concentration limit for the embedding (solubility) of the oxides of rare earth elements (REEs). The concentration ratios Er2O3/AlPO4 and Yb2O3/AlPO4 that provide a high amplification efficiency and a low level of optical loss in lightguides are determined.

The interaction of 5-methyl-2-phenyl-4-[(8-quinolylhydrazono)]pyrazol-3-one (2) and 5-methyl-2-phenyl-4-(8-quinolylhydrazono)pyrazole-3-thione (4) with copper(II) acetate monohydrate under reflux in ethanol results in the formation of copper(II) azo chelates incorporating CuN4O2 (5) and CuN3S2 (6) chromophores. All the compounds were characterized with FT-IR, EPR, X-ray absorption spectroscopy and magnetic measurements. The structures of complexes 5 and 6 were determined by X-ray single-crystal diffraction. Complex 5 adopts a pseudo-octahedral geometry with a cis disposition of the oxygen atoms around the copper(II) centre, whilst in 6 the copper(II) ion displays a square-pyramidal geometry with a {N3S2} ligand environment.

Nanocomposites comprise functionalised multi-walled carbon nanotubes (0.00 wt%, 0.05 wt% and 0.07 wt%) and ferroelectric liquid crystals (FLCs) have been studied in the 5-μm- and 12-μm-thickness ce...

In this paper, we demonstrated the possibility of efficient dispersion management using a newly developed asymptotically single-mode hybrid fiber that has anomalous dispersion in the 1 μm spectral range. Of the few internal modes of the hybrid fiber, only one mode can propagate at a length longer than 6 m because of the mode's differential optical absorption. This feature was achieved by inserting a highly absorbing ring layer at the position of the electric field minimum of the hybrid mode. About 10 m of an asymptotically single-mode hybrid fiber with an anomalous dispersion of ∼65 ps/(nm⋅km) at 1064 nm was used for the compression of 7 ps chirped pulses down to 440 fs duration. The use of the same hybrid fiber with a length of 6.5 m for intracavity dispersion management allowed us to demonstrate the stable operation of a ring soliton laser scheme based on a semiconductor satiable absorbing mirror. Pulses with duration of approximately 700 fs, a peak power of 850 W and energy as high as 0.55 nJ were extracted directly from the laser.

Several new comb-like stereoregular cyclolinear methylsiloxane copolymers exhibiting the self-assembling behaviour have been designed and studied. For the resulting macromolecular materials, the chiral mesogenic unit, namely (S)-(–)-4-[1-ethoxycarbonyl)ethoxycarbonyl]phenyl-4′-[11-tetramethyldisiloxyl)-undecenyloxy)-biphenyl-4′-carboxylate, has been used as a side group to assure the mesomorphic behaviour. The mesomorphic and structural properties were studied by the polarising optical microscopy, differential scanning calorimetry and small-/wide-angle X-ray diffraction techniques. The designed copolymers form the orthogonal smectic A* and the tilted smectic C* phases over relatively broad temperature range, down to room temperatures. The obtained results are discussed in order to contribute to better understanding of the molecular architecture–nano-organisation relationship for a specific type of macromolecular system based on the lactic acid derivatives used as a flexible side groups.

We propose a novel saddle-shaped Yb-doped fiber design for high power generation in the spectral range near 0.976 $\mu \text{m}$ . The fiber has a central single-mode part with a core diameter of approximately $12~\mu \text{m}$ and an ultra-thin silica clad of approximately $49~\mu \text{m}$ . At both ends of the fiber, the core/clad diameters were adiabatically increased up to 20/80 $\mu \text{m}$ to be compatible with ordinary passive fibers. A monolithic 976-nm single-mode continuous wave laser based on the proposed fiber was created. The laser’s power was a record high compared with all-fiber laser schemes, with an output power of 10.6 W. Utilization of a photodarkening-free core glass matrix has allowed us to demonstrate perfect long-term stability (without any power degradation) of the developed laser over 45 h.

The spectral window around 1700 nm is interesting for in-depth multiphoton microscopy of intact tissues due to reduced scattering and absorption in this wavelength range. However, wide adoption of this excitation range will rely on the availability of robust and cost-effective high peak power pulsed lasers operating at these wavelengths. Here, we report on a fiber-based femtosecond laser providing up to 95 nJ, 85 fs pulses at 1800 nm. The laser system makes use of a fiber-based chirped pulse amplifier emitting at 1560 nm followed by an in-house fabricated very large mode area antiresonant fiber for soliton self-frequency shift. Megawatt-peak power pulses at the repetition rate of 1 MHz are available directly at the output of the flexible fiber. We illustrate the potential of the source for biological microscopy by recording three-photon-excited fluorescence images of mouse nervous tissue. The flexible fiber tailored to propagate megawatt solitons in the biologically relevant window around 1700 nm opens the way to deep brain imaging of freely moving animals via miniaturized endomicroscopes.

The bite angle of chelating diphosphines is often responsible for the activity and the selectivity of rhodium catalysts based on them. The EPR study of the composition and the structure of similar complexes with o -semiquinonic ligands is reported. The reaction of the diphosphines with dicarbonyl- o -semiquinonato rhodium complexes gives a variety of new products including o -semiquinonato complexes of monovalent rhodium and catecholates of divalent rhodium as well. Some of latter catecholates demonstrate the coordination sphere dynamics similar with Berry’s either turnstile mechanism. The composition, the structure and the properties of the formed compounds are defined by diphosphine bite angle.

We present multimode fiber lasers for tandem pumping of high power Er-, Tm-, and Yb-doped lasers. These pump sources are based on especially developed multimode Er- and Yb-doped double-clad fibers. Er-doped lasers with record pump conversion efficiency >48% at 1565 nm and more than 41% at 1535 and 1590 nm were realized. Yb-doped fiber laser at 1020 nm with record high 85% pump conversion efficiency was demonstrated. Also, we propose novel design of compact and cost-effective multimode laser scheme. The potential of power scaling of proposed lasers to the 1-10-kW level and their advantages as resonant pump sources are discussed.

Microbiome-modulating interventions are promising for treatment and prevention of metabolic syndrome. The number of probiotic strains demonstrated ability to decrease cholesterol level in vivo, however, it was poorly confirmed in a clinical setting. The aim was to study the effects of L. acidophilus IMV B-7279, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB separately and in various compositions on the level of serum cholesterol, gut microbiota contents and liver morphology on a high-calorie-induced obesity model in BALB/c mice. We used for the study female BALB/c mice 6–8 weeks old (18–24 g). Experimental animals were fed by a fat-enriched diet (FED), and 8 experimental groups were formed (12 mice in each group) to test strains of probiotic bacteria L. delbrueckii subsp. bulgaricus IMV B-7281, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB and compositions. We used ultrasound for in vivo assessment of the liver and visceral (mesenteric) fat size. In the blood serum of the obese mice, the level of cholesterol was estimated. The liver morphology and gut microbiota of obese mice were studied. We revealed that after treatment with all of the studied probiotic bacteria and compositions of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280, the weight of obese mice decreased, and cholesterol and its fraction levels in serum were reduced. The size of the liver slightly decreased after treatment with L. delbrueckii subsp. bulgaricus IMV B-7281, B. аnimalis VKB or probiotic compositions; we observed reduction of the mesenteric fat size after injection of all these probiotic bacteria (separately) and probiotic compositions. We defined the strain-dependent effects on serum lipid profiles, liver morphology and the gut microbiota. The B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 composition effectively recovered the liver morphological structure of obese mice. The number of Lactobacillus spp., Bifidobacterium spp. and coliform bacteria increased, the number of staphylococci and streptococci reduced, and the number of microscopic fungi significantly decreased in the gut of obese mice after treatment with L. casei IMV B-7280, L. delbrueckii subsp. bulgaricus IMV B-7281, B. animalis (separately) or their compositions. L. casei IMV B-7280 (separately) and a composition of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 are effective at decreasing the weight of obese mice, decreasing cholesterol level, restoring the liver morphology and beneficially modulating the gut microbiome in high-calorie-induced obesity.

Treatment of the aromatic aminonitrones p -RC 6 H 4 C(NH 2 ) N + (Me)O − (R = NMe 2 , Cl) with CuCl 2 ·2H 2 O, NiCl 2 ·2H 2 O, β -PdCl 2 , or cis -[PtCl 2 (Me 2 S O) 2 ] in the presence of a base leads to the [M{ p -RC 6 H 4 C( N H) N + (Me) O − } 2 ] (M = Cu, Ni, Pd) (72–95%) or [Pt{ p -RC 6 H 4 C( N H) N + (Me) O – }Cl(Me 2 S O)] (ca. 80%) complexes, respectively. These compounds were characterized by elemental analyses (C, H, N), HRESI + -MS, FTIR, 1 H and 13 C{ 1 H} NMR, and for the Cu II and Ni II complexes EPR and magnetic susceptibility. In addition, eight species were studied by single-crystal X-ray diffraction. In the X-ray structures of 2a – d , the hydrogen bonds are responsible for the formation of 1D polymeric chains. These bonds were evaluated by DFT calculations (M06/DZP-DKH level of theory) and topological analysis of the electron density distribution within the formalism of Bader’s theory (QTAIM method). Estimated strengths of these non-covalent interactions are 2.7–4.4 kcal/mol.

Recently probiotics have been started to be commonly used as a subsidiary therapy during many illnesses, such as intestinal and urogenital infections, diseases of the gastrointestinal and respiratory tract, also joints and connective tissue lesions, some cancers, allergies, dermatological and dental diseases. However, there are still no summary guidelines for selection and estimation of probiotic strains for different clinical cases. Thus, we have made a general conclusion of estimation of probiotics` quality and development of rational principles of probiotic therapy usage in clinical practice during the treatment of patients with the most common diseases and for their prevention. There are described key principles of implementation of step-by-step estimation of probiotic culture quality in foodstuff according to regulations of World Health Organization, European Union, Ukraine and other countries. The requirements are presented for the evaluation of safety of probiotic cultures, which include testing of their in vitro and in vivo activity in different experimental models, as well as a study of their therapeutic efficacy in clinical practice in the treatment of patients and in long periods after probiotic therapy. Also there are some evidences of possible side effects, risks or low efficiency that depends on individual characteristics of the gut microbiota quantitative and qualitative composition of each patient and stage, heaviness of clinical course of each specific disease. That`s why it is very important to take all circumstances of patients` status into account and collect all previous stored knowledge of probiotics` usage

We developed a highly efficient double-clad Yb-doped polarization-maintaining fiber to be implemented for small-signal amplification near 0.976 μm. The fiber was designed to have a relatively small mode field diameter compatible with standard step-index single-mode optical fibers. Another feature of the fiber was a small threshold for 0.976 μm signal amplification, which was achieved by a creation of a thin inner cladding (80 μm diameter). The unique design of the fiber allowed us to construct successfully an all-fiber picoseconds mode-locked laser at 0.98 μm for the first time to the best of our knowledge.

We proposed and experimentally demonstrated a technique for the suppression of unwanted modes in double-clad fibers with a high core-to-clad diameter ratio by introducing high-index absorbing inclusions into the first cladding of the fibers. These inclusions disturb the shape of undesirable modes, and a noticeable part of the power becomes localized inside the inclusion, resulting in an increase in the propagation loss of these modes. Two fiber designs were studied and realized: one with cylindrical symmetry and an absorbing high-index ring as the inclusion and another with high-index absorbing rods inserted around the fiber core. In both cases, the possibility of achieving perfect single-mode propagation was demonstrated both theoretically and experimentally.

BACKGROUND: Microbiome modulation is a pillar intervention to treat metabolic syndrome, prestages, and cascade of related pathologies such as atherosclerosis, among others. Lactobacillus and Bifidobacterium probiotic strains demonstrate efficacy to reduce obesity, dyslipidemia, and improve metabolic health. Novel prebiotic substances composed with known probiotics may strongly synergize health benefits to the host. The aim of this study was to evaluate beneficial effects of Lactobacillus and Bifidobacterium strains (probiotics) if composed with nanoceria (potential prebiotic) to reduce cholesterol levels and restore gut microbiota in obese mice. MATERIALS AND METHODS: Two lines of mice were used in the study: BALB/c mice (6–8 weeks, 18–24 g) and CBA mice (11–12 months, 20–26 g); experimental animals were fed by fat-enriched diet 3 weeks before the evaluation. Animals were divided into groups to test probiotic strains and nanoceria. All groups received probiotic strains orally and cerium dioxide orally or intravenously in various composition. A group of untreated animals was used as a control. Cholesterol level and gut microbiota of mice were studied. RESULTS: Cerium dioxide nanoparticles, probiotic strain L. casei ІМV В-7280, and composition B. animalis VKB/B. animalis VKL applied separately and in different combinations all reduced at different levels free and bound cholesterol in blood serum of mice fed by fat-enriched diet. The combination of 0.01 M nanoceria and probiotic strain L. casei ІМV В-7280 resulted in the fastest cholesterol level decrease in both young and mature animals. Oral administration of CeO(2) applied alone reduced the number of microscopic fungi in the gut of mice and Gram-positive cocci (staphylococci and/or streptococci). Application of L. casei IMV B-7280 as a probiotic strain increased most significantly the number of lactobacilli and bifidobacteria in the gut of mice. The most significant normalization of gut microbiota was observed after oral administration of alternatively either L. casei IMV B-7280 + 0.1 M CeO(2) or L. casei IMV B-7280 + 0.01 M CeO(2). CONCLUSION: Dietary application of nanoceria combined with probiotic strains L. casei IMV B-7280, B. animalis VKB, and B. animals VKL has significantly reduced both free and bound cholesterol levels in serum. Simultaneous administration of probiotics and cerium nanoparticles as a prebiotic, in various combinations, significantly enhanced positive individual effects of them on the gut microbiota spectrum. The presented results provide novel insights into mechanisms behind nutritional supplements and open new perspectives for application of probiotics combined with substances demonstrating prebiotic qualities benefiting, therefore, the host health. Follow-up translational measures are discussed to bring new knowledge from lab to the patient. If validated in a large-scale clinical study, this approach might be instrumental for primary and secondary prevention in obese individual and patients diagnosed with diabetes. To this end, individualized prediction and treatments tailored to the person are strongly recommended to benefit the health condition of affected individuals.

Er-Yb fibers are routinely used for generation of watt-level signal near 1.55 μm. Such fibers typically have core doped with a high P 2 O 5 concentration (required for efficient energy transfer from Yb3+ to Er3+ ions) which result in a high core numerical aperture (NA) of about 0.2. As a results single-mode Er-Yb fibers has a small core diameter (∼5 μm) and they are not suitable for high peak power applications. In the current communication we report on development of Er-Yb fibers with a low core NA based on highly fluorine doped P 2 O 5 -SiO 2 glass.

Single-frequency high peak power pulsed lasers operating in the 1.55 μm spectral range are required in many applications such as wind sensing LIDAR and gas column sensing. When pulse duration exceeds 10–20 ns the main limitation for peak power comes from Stimulated Brillouin Scattering (SBS). To date the highest peak power in all-fiber single-mode laser scheme was demonstrated in [1] using Er-doped (Yb-free) double clad cladding pumped large mode area fiber (EDF). The maximum peak power above 4 kW was demonstrated, however the pump to signal conversion efficiency (PCE) was only 5% with respect to launched pump power. Increase of PCE to 12% was demonstrated in the same work using longer fiber, but peak power was decreased down to 950 W. Utilization of specialty technique for SBS suppression allows one to improve these results. In particular applying of gradient stress to large mode area Er-Yb fibers (EYDF) resulted in achievement of 1 kW peak power and 16.5% PCE [2].

Ultrashort pulse fiber laser systems with both high average and peak power are promising tools for a wide range of applications. Usually pulsed fiber laser systems exhibit either high average power [1] or high peak power [2]. Only utilization of rod-photonics-crystal-fiber technology [3] allows one to achieve both high average (130 W) and peak (870 kW) power with a price of non-monolithic design (mainly bulk elements are used in [3], which lead to the laser's high cost and lose of reliability). Moreover not perfectly single-mode output (M2 = 1.30) results in limitation of maximum average power caused by mode instability. Recently sub-MW peak power in monolithic all-fiber laser scheme was demonstrated in [4] using tapered fiber approach. Scalability of average power in tapered fiber to 28 W at peak power of 292 kW was demonstrated in [5]. In the current communication we demonstrated further progress in average and peak power scaling using this approach.