Transformational features of the vein wall during a long-term period of endovenous laser ablation using 1910 nm laser radiation. Results of in-vivo experiments.

BACKGROUND: In this paper, results of in-vivo experiments on the animals of endovenous laser ablation (EVLA) using laser radiation with the wavelength 1910 nm are reported. The results of histological studies of the vein segments removed immediately after the procedure and in a long-term period (30 days and 3 months) are presented. Their structural transformation and the obliteration degree of the vein lumen using different values of the linear energy density of laser radiation (LEED=7.5; 15; 20 J/cm) are estimated. METHODS: Edilbay breed of sheep (males) were used as experimental animals. Laser radiation with a wavelength of λ=1910 nm and power of Рrad = 1.5, 3, 4 W was used for EVLA experiments, and speed of fiber traction (v) was 2 mm/s. 8 days after EVLA stitches and an elastic bandage were removed. Animals were observed for 3 months in the vivarium. Animals have duplex ultrasound scanning of coagulation veins under anesthesia, after analysis vein segments were excised for histological examination. As a result, the damage degree to the vein wall tissues (intima, media, adventitia) and peri-venous tissues was revealed. RESULTS: It is shown that in the long-time period, the intima and partial muscle layer transformed to connective tissue. EVLA using laser radiation with a higher value of LEED led to the growth of connective tissue, oedema of all vein layers and peri-venous tissue. The lumen closure occurred due to clot and the vein wall transformation, a maximum value was 25% using LEED=20 J/cm. CONCLUSIONS: The connective-tissue transformation of the coagulated vein occurs in a long-term period and more pronounced for higher LEED. However, features of vein hemodynamics of animals and differences between the clot formation process of human varicose veins and healthy animal veins lead to incomplete occlusion. These features should be taken into account during extrapolation results of experiments on animals in clinical practice.

Noise-induced switching in dynamics of oscillating populations coupled by migration.

The problem of identifying the sources of switching in the dynamics of nonlinear coupled systems and their mathematical prediction is considered. We study a metapopulation system formed by two oscillating subpopulations coupled by mutual migration. For this model, parametric zones of mono-, bi-, and tri-rhythmicity with the coexistence of regular and chaotic attractors are revealed. The effects of random perturbations in the migration intensity parameter are studied both by methods of statistical analysis of the results of direct numerical simulation and by using the analytical technique of stochastic sensitivity. Noise-induced transitions between anti- and in-phase synchronization modes, as well as between order and chaos, are being studied. Here, the role of transient chaotic attractors and their fractal basins is discussed.

Erbium-Doped Lu2O3-MgO and Sc2O3-MgO IR-Transparent Composite Ceramics.

Novel IR-transparent ceramics of erbium-doped Lu2O3-MgO and Sc2O3-MgO composites have been successfully obtained using a combination of glycine-nitrate self-propagating high-temperature synthesis and vacuum hot-pressing methods. Composites have densities greater than 99.5% of those calculated by X-ray diffraction and consist of uniformly distributed submicron grains of magnesium and rare earth oxides. The transmittances of 1.5 mm thick composites are as high as 84.5% and 78.9% at ~5 µm for Er:Lu2O3-MgO and Er:Sc2O3-MgO, respectively. Both composites are favorable matrices for doping with erbium ions, which exhibit intense luminescence in the visible, near, and mid-IR under relevant excitation. The position of the luminescence bands is similar to Er:Lu2O3 and Er:Sc2O3 ceramics; the lifetimes of the 4I13/2 state are 8.85 ± 0.1 ms and 5.7 ± 0.2 ms for 3%Er:Lu2O3-MgO and 3%Er:Sc2O3-MgO, respectively.

Morphological changes of veins and perivenous tissues during endovenous laser coagulation using 2-µm laser radiation and various types of optical fibers.

OBJECTIVE: To determine the morphological changes in veins and perivenous tissues after endovenous laser coagulation (EVLC) using laser radiation with a wavelength of 1910 nm and different types of fibers (bare tip and radial). METHODS: The EVLC procedure was carried out on 22 surface veins of six sheep. The radiation source was a diode-pumped solid-state laser, which was based on a LiYF4:Tm crystal and had an emission wavelength of 1910 nm and a maximum output power of 10 W. Two types of optical fibers were used: (1) bare tip and (2) radial or radial with two rings. Histological and morphometric methods were used, and the statistical digital data were analyzed. RESULTS: The use of a linear endovenous energy density of 20 J/cm and optical bare fibers for veins with diameters of 3-4 mm resulted in a slit-shaped or wide venous wall perforation. A thermal effect was observed on the perivenous connective tissue (PVCT), which caused damage to its structures. Wide perforations were accompanied by complete destruction of the PVCT in the projection of the formed defect. The distance between the remaining vein wall fragment, located opposite to the perforation, and injured small vessels was 257.7 ± 23.6 µm. The radius of thermal damage increased to 2073.5 ± 8.0 µm near the vessel perforation. Using optical radial fibers for veins with diameters of 3.9 ± 0.5 mm did not lead to perforations. The destructive effect of the laser on small vessels of the PVCT extended to a distance of 425.7 ± 22.0 µm. CONCLUSIONS: Analysis of thermal vessel damage in perivenous tissue after EVLC with bare-tip fiber shows that in the projection of a wide perforation, the damaged vessels of the PVCT are located at a large distance from the coagulated vein wall. On the opposite side of the perforation, the distance from the coagulated vein wall to the damaged vessels of the PVCT is significantly reduced because of the minimal output of laser radiation energy through the poorly damaged part of the wall. Using an optical radial fiber facilitates the application of a uniform distribution of thermal energy to the vein wall and damage to all its layers; at the same time, it minimizes the thermal energy that extends beyond the vein wall and damages the surrounding tissue. CLINICAL RELEVANCE: The use of radiation with a wavelength of 1910 nm will make it possible to carry out endovenous laser coagulation of varicose veins at lower power values compared with radiation in the micron and one and a half micron regions of the spectrum. Understanding of morphological changes of veins and perivenous tissues after endovenous laser coagulation with 1910-nm laser radiation and different types of optical fibers (bare-tip, radial, radial 2ring) help predict possible complications and reduce their rate.

Influence of SHS Precursor Composition on the Properties of Yttria Powders and Optical Ceramics.

This study looked at optimizing the composition of precursors for yttria nanopowder glycine-nitrate self-propagating high-temperature synthesis (SHS). Based on thermodynamic studies, six different precursor compositions were selected, including with excesses of either oxidant or fuel. The powders from the precursors of all selected compositions were highly dispersed and had specific surface areas ranging from 22 to 57 m2/g. They were consolidated by hot pressing (HP) with lithium-fluoride sintering additive and subsequent hot isostatic pressing (HIP). The 1 mm thick HPed ceramics had transmittance in the range of 74.5% to 80.1% @ 1µm, which was limited by optical inhomogeneity due to incomplete evaporation of the sintering additive. Two-stage HIP significantly improves optical homogeneity of the ceramics. It was shown that an excess of oxidizer in the precursor decreases the powders' agglomeration degree, which forms large pore clusters in the ceramics.

Prevalence of Toxoplasma gondii infection among small mammals in Tatarstan, Russian Federation.

Toxoplasma gondii is a zoonotic parasite with a wide host range that includes humans, domestic animals and wild animals. Small mammals serve as intermediate hosts for T. gondii and may contribute to the persistence of this parasite in the environment. Mass mortality in wild animals and deaths in rare endemic species make the study of this parasite of growing importance. In this study, T. gondii infection prevalence was evaluated in brain tissues from 474 small mammals captured at 26 trapping points in urban and rural areas of Tatarstan, Russian Federation. Nested PCR was used to detect the T. gondii B1 gene in the samples. Overall, 40/474 samples (8.44%) showed B1 gene positivity. T. gondii infection among the wild small mammals trapped in the rural area was significantly higher as a whole than that of the urban area as a whole. Multivariate logistical regression analysis also showed that the trapping area (rural or urban) significantly contributed to T. gondii positivity. Vegetation in the trapping points, small mammal species, sex, age or distance from the trapping points to the nearest human settlements did not significantly affect T. gondii positivity in the sampled small mammals.

Thermo-Optical Studies of Laser Ceramics.

A cycle of works on manufacturing and studying laser and magnetooptical ceramics with a focus on their thermo-optical characteristics performed by the research team is analyzed. Original results that have not been published before such as measurements of the Verdet constant in the Zr:TAG, Re:MgAl2O4, and ZnAl2O4 ceramics are also presented.

Automated Design and Integration of Asset Administration Shells in Components of Industry 4.0.

One of the central concepts in the principles of Industry 4.0 relates to the methodology for designing and implementing the digital shell of the manufacturing process components. This concept, the Asset Administration Shell (AAS), embodies a systematically formed, standardized data envelope of a concrete component within Industry 4.0. The paper discusses the AAS in terms of its structure, its components, the sub-models that form a substantial part of the shell's content, and its communication protocols (Open Platform Communication-Unified Architecture (OPC UA) and MQTT) or SW interfaces enabling vertical and horizontal communication to involve other components and levels of management systems. Using a case study of a virtual assembly line that integrates AASs into the technological process, the authors present a comprehensive analysis centered on forming AASs for individual components. In the given context, the manual AAS creation mode exploiting framework-based automated generation, which forms the AAS via a configuration wizard, is assessed. Another outcome consists of the activation of a virtual assembly line connected to real AASs, a step that allows us verify the properties of the distributed manufacturing management. Moreover, a discrete event system was modeled for the case study, enabling the effective application of the Industry 4.0 solution.

Prevalence of the Puumala orthohantavirus Strains in the Pre-Kama Area of the Republic of Tatarstan, Russia.

Puumala orthohantavirus (PUUV) causes nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS) commonly diagnosed in Europe. The majority of HFRS cases in the European part of Russia are diagnosed in the Volga Federal District, which includes the Republic of Tatarstan (RT). The current study aims to analyze the genetic variability of PUUV in Pre-Kama region of the RT bounded by the Volga, Kama, and Vyatka rivers. In 2017, bank voles were caught in seven isolated forest traps in the Pre-Kama region and for the 26 PUUV-positive samples, the partial small (S), medium (M), and large (L) genome segment sequences were obtained and analyzed. It was determined that all identified PUUV strains belong to the Russian (RUS) genetic lineage; however, the genetic distance between strains is not directly correlated with the geographical distance between bank vole populations. One of the identified strains has S and L segments produced from one parental strain, while the M segment was supplied by another, suggesting that this strain could be the reassortant. We suggest that the revealed pattern of the PUUV strains distribution could be the result of a series of successive multidirectional migratory flows of the bank voles to the Pre-Kama region in the postglacial period.

Optimization of endovenous laser coagulation: in vivo experiments.

Finding optimal parameters of endovenous laser coagulation using the radiation with a wavelength of 1910 nm. In vivo experiments have been carried out on the small saphenous veins of three sheep of Edilbay breed and the dependence of venous wall and surrounding tissue damage on the radiation power was analyzed on the basis of morphological study results, as well as ultrasound examination and clinical observation of animals in the postoperative period. As radiation source, we used the diode-pumped solid-state laser, based on the LiYF4:Tm crystal, with emission wavelength of 1910 nm. For morphological study, veins were harvested immediately and 40 days after operation. Histological analysis of the vein after treatment with 1.5-W radiation revealed asymmetric wall injury and a thrombus formation in the lumen. The blood thrombus formation and pronounced vein wall damage was observed after treatment with 3-W radiation. Perivenous tissue injury is insignificant and does not lead to postoperative complications as in the case of using 1.5-W radiation. Increasing the radiation power to 4 W results in the total vein wall destruction and the thrombus formation, which persists for 40 days after the procedure. Based on the results of clinical observations of animals with registration of skin wound healing, as well as the results of histological examination of veins harvested immediately after the EVLC and 40 days after, it was concluded that the laser power value of 3-4 W can be recommended for use in the clinic.

New Approaches to Implementing the SmartJacket into Industry 4.0 ‡.

The paper discusses the possibilities of incorporating sensors and indicators into the environment of an Industry 4.0 digital factory. The concept of Industry 4.0 (I4.0) is characterized via a brief description of the RAMI 4.0 and I4.0 component model. In this context, the article outlines the structure of an I4.0 production component, interpreting such an item as a body integrating the asset and its electronic form, namely, the Asset Administration Shell (AAS). The formation of the AAS sub-models from the perspectives of identification, communication, configuration, safety, and condition monitoring is also described to complete the main analysis. Importantly, the authors utilize concrete use cases to demonstrate the roles of the given I4.0 component model and relevant SW technologies in creating the AAS. In this context, the use cases embody applications where an operator wearing a SmartJacket equipped with sensors and indicators ensures systematic data collection by passing through the manufacturing process. The set of collected information then enables the operator and the system server to monitor and intervene in the production cycle. The advantages and disadvantages of the individual scenarios are summarized to support relevant analysis of the entire problem.

Adaptive curvature-guided image filtering for structure + texture image decomposition.

A preliminary structure + texture image decomposition is very useful for a number of digital image processing tasks, as different strategies are supposed to be employed for processing the structure and texture image components. In this paper, a new variational structure + texture image decomposition method is developed. The main ingredients of the proposed approach are: (1) using a low-pass filtered level-set curvature of the input image as a guidance image; (2) texture suppressing by minimizing a variable exponent energy, where the variable exponent is learned from the result of the curvature-guided image filtering. Numerical experiments demonstrate that the method is competitive with the current state of the art in structure + texture image decomposition. Several applications are considered.

Field evaluation of a 0.005% fipronil bait, orally administered to Rhombomys opimus, for control of fleas (Siphonaptera: Pulicidae) and phlebotomine sand flies (Diptera: Psychodidae) in the Central Asian Republic of Kazakhstan.

Plague (Yersinia pestis) and zoonotic cutaneous leishmaniasis (Leishmania major) are two rodent-associated diseases which are vectored by fleas and phlebotomine sand flies, respectively. In Central Asia, the great gerbil (Rhombomys opimus) serves as the primary reservoir for both diseases in most natural foci. The systemic insecticide fipronil has been previously shown to be highly effective in controlling fleas and sand flies. However, the impact of a fipronil-based rodent bait, on flea and sand fly abundance, has never been reported in Central Asia. A field trial was conducted in southeastern Kazakhstan to evaluate the efficacy of a 0.005% fipronil bait, applied to gerbil burrows for oral uptake, in reducing Xenopsylla spp. flea and Phlebotomus spp. sand fly abundance. All active gerbil burrows within the treated area were presented with ~120 g of 0.005% fipronil grain bait twice during late spring/early summer (June 16, June 21). In total, 120 occupied and 14 visited gerbil colonies were surveyed and treated, and the resulting application rate was minimal (~0.006 mg fipronil/m2). The bait resulted in 100% reduction in Xenopsylla spp. flea abundance at 80-days post-treatment. Gravid sand flies were reduced ~72% and 100% during treatment and at week-3 post-treatment, respectively. However, noticeable sand fly reduction did not occur after week-3 and results suggest environmental factors also influenced abundance significantly. In conclusion, fipronil bait, applied in southeastern Kazakhstan, has the potential to reduce or potentially eliminate Xenopsylla spp. fleas if applied at least every 80-days, but may need to be applied at higher frequency to significantly reduce the oviposition rate of Phlebotomus spp. sand flies. Fipronil-based bait may provide a means of controlling blood-feeding vectors, subsequently reducing disease risk, in Central Asia and other affected regions globally.

Polarization Effects in Graded AlGaN Nanolayers Revealed by Current-Sensing and Kelvin Probe Microscopy.

We experimentally demonstrate that the conductivity of graded AlxGa1-xN increases as a function of the magnitude of the Al concentration gradient (%Al/nm) due to polarization doping effects, without the use of impurity dopants. Using three up/down-graded AlxGa1-xN nanolayers with Al gradients ranging from ∼0.16 to ∼0.28%Al/nm combined in one structure, the effects of polarization engineering for localized electric fields and current transport were investigated. Cross-sectional Kelvin probe force microscopy and conductive atomic force microscopy were used to directly probe the electrical properties of the films with spatial resolution along the thickness of the growth. The experimental profiles of the built-in electric fields and the spreading current found in the graded layers are shown to be consistent with simulations of the field distribution as well as of the electron and hole densities. Finally, it was directly observed that for gradients less than 0.28%Al/nm the native n-type donors still limit polarization-induced hole doping, making p-type conductivity still a challenge due to background impurities and defects.

New library construction method for single-cell genomes.

A central challenge in sequencing single-cell genomes is the accurate determination of point mutations, phasing of these mutations, and identifying copy number variations with few assumptions. Ideally, this is accomplished under as low sequencing coverage as possible. Here we report our attempt to meet these goals with a novel library construction and library amplification methodology. In our approach, single-cell genomic DNA is first fragmented with saturated transposition to make a primary library that uniformly covers the whole genome by short fragments. The library is then amplified by a carefully optimized PCR protocol in a uniform and synchronized fashion for next-generation sequencing. Each step of the protocol can be quantitatively characterized. Our shallow sequencing data show that the library is tightly distributed and is useful for the determination of copy number variations.

Infrared Reflectance Analysis of Epitaxial n-Type Doped GaN Layers Grown on Sapphire.

Infrared (IR) reflectance spectroscopy is applied to study Si-doped multilayer n+/n0/n+-GaN structure grown on GaN buffer with GaN-template/sapphire substrate. Analysis of the investigated structure by photo-etching, SEM, and SIMS methods showed the existence of the additional layer with the drastic difference in Si and O doping levels and located between the epitaxial GaN buffer and template. Simulation of the experimental reflectivity spectra was performed in a wide frequency range. It is shown that the modeling of IR reflectance spectrum using 2 × 2 transfer matrix method and including into analysis the additional layer make it possible to obtain the best fitting of the experimental spectrum, which follows in the evaluation of GaN layer thicknesses which are in good agreement with the SEM and SIMS data. Spectral dependence of plasmon-LO-phonon coupled modes for each GaN layer is obtained from the spectral dependence of dielectric of Si doping impurity, which is attributed to compensation effects by the acceptor states.

Porous biomorphic silicon carbide ceramics coated with hydroxyapatite as prospective materials for bone implants.

Porous and cytocompatible silicon carbide (SiC) ceramics derived from wood precursors and coated with bioactive hydroxyapatite (HA) and HA-zirconium dioxide (HA/ZrO2) composite are materials with promising application in engineering of bone implants due to their excellent mechanical and structural properties. Biomorphic SiC ceramics have been synthesized from wood (Hornbeam, Sapele, Tilia and Pear) using a forced impregnation method. The SiC ceramics have been coated with bioactive HA and HA/ZrO2 using effective gas detonation deposition approach (GDD). The surface morphology and cytotoxicity of SiC ceramics as well as phase composition and crystallinity of deposited coatings were analyzed. It has been shown that the porosity and pore size of SiC ceramics depend on initial wood source. The XRD and FTIR studies revealed the preservation of crystal structure and phase composition of in the HA coating, while addition of ZrO2 to the initial HA powder resulted in significant decomposition of the final HA/ZrO2 coating and formation of other calcium phosphate phases. In turn, NIH 3T3 cells cultured in medium exposed to coated and uncoated SiC ceramics showed high re-cultivation efficiency as well as metabolic activity. The recultivation efficiency of cells was the highest for HA-coated ceramics, whereas HA/ZrO2 coating improved the recultivation efficiency of cells as compared to uncoated SiC ceramics. The GDD method allowed generating homogeneous HA coatings with no change in calcium to phosphorus ratio. In summary, porous and cytocompatible bio-SiC ceramics with bioactive coatings show a great promise in construction of light, robust, inexpensive and patient-specific bone implants for clinical application.

The Peculiarities of Strain Relaxation in GaN/AlN Superlattices Grown on Vicinal GaN (0001) Substrate: Comparative XRD and AFM Study.

Superlattices (SLs) consisting of symmetric layers of GaN and AlN have been investigated. Detailed X-ray diffraction and reflectivity measurements demonstrate that the relaxation of built-up strain in the films generally increases with an increasing number of repetitions; however, an apparent relaxation for subcritical thickness SLs is explained through the accumulation of Nagai tilt at each interface of the SL. Additional atomic force microscopy measurements reveal surface pit densities which appear to correlate with the amount of residual strain in the films along with the appearance of cracks for SLs which have exceeded the critical thickness for plastic relaxation. These results indicate a total SL thickness beyond which growth may be limited for the formation of high-quality coherent crystal structures; however, they may indicate a growth window for the reduction of threading dislocations by controlled relaxation of the epilayers.

X-ray Reciprocal Space Mapping of Graded Al x Ga1 - x N Films and Nanowires.

The depth distribution of strain and composition in graded Al x Ga1 - x N films and nanowires (NWs) are studied theoretically using the kinematical theory of X-ray diffraction. By calculating [Formula: see text] reciprocal space maps (RSMs), we demonstrate significant differences in the intensity distributions from graded Al x Ga1 - x N films and NWs. We attribute these differences to relaxation of the substrate-induced strain on the NWs free side walls. Finally, we demonstrate that the developed X-ray reciprocal space map model allows for reliable depth profiles of strain and Al composition determination in both Al x Ga1 - x N films and NWs.