ZnO–SnO2–Ag(AgCl) nanocomposites consisting of hexagonal ZnO, tetragonal SnO2, metallic Ag and AgCl nanocrystals were prepared by wet polymer-salt synthesis. The materials were studied using optical and luminescent spectroscopy, SEM, EDS and XRD analysis. The ability to generate chemically active singlet oxygen and antibacterial activity of prepared materials against both gram-positive and gram-negative bacteria were tested. It was showed that Ag structural transformation starts in initial composite solutions and proceeds at all stages including drying and thermal treatment of ZnO–SnO2–Ag(AgCl) synthesis. During this transformation, Ag exists in different forms (ions, molecular clusters, metallic and salt (AgCl) nanoparticles) and structural states (free Ag+ ions and Ag-PVP complexes in the solutions; Ag+ ions embedded into oxides crystal matrices; molecular clusters in the solutions and in PVP-salt composites; nanoparticles). Synthesized ZnO–SnO2–Ag(AgCl) powders consist of small (about 50 nm) nanoparticles—“nanogenerators” of chemically active singlet oxygen. This provides high antibacterial activity of these materials against both gram-positive and gram-negative bacteria.

Significant improvement of photoactive and bactericidal properties of oxide nanocomposites due to the spatial separation of forming nanoparticles during thermochemical synthesis has been described. The evolution processes proceeding at different stages of the nanocomposites synthesis were studied by optical and luminescent spectroscopy, XRD and SEM analysis. Polyvinylpyrrolidone plays the double role during nanocomposites synthesis: as the stabilizing component at initial solutions stages and as a fuel during materials calcination. The synthesized materials demonstrate the ability to generate chemically active singlet oxygen under UV irradiation and high antibacterial activity. Created nanocomposites are promising for different medical and environmental application.

This work describes the study of the synthesis and characterization of bactericidal ZnO-SnO2 nanocomposites prepared by polymer-salt method. The structure and morphology of prepared materials were studied by XRD and SEM analysis. Prepared ZnO-SnO2 nanocomposites demonstrate the ability to generate singlet oxygen under external irradiation and high antibacterial activity against both gram-positive (Staphylococcus aureus ATCC 209P) and gram-negative (Escherichia coli ATCC 25922) bacteria. Antibacterial effect increases significantly with the growth of SnO2 addition content up to 9-12 mol% content that is related to the decrease of ZnO nanocrystals sizes and the corresponding increase of materials specific surface areas.

Currently, numerous projects for the study of both outer space and the Earth's surface use mirror optical systems, since they allow working in a wide spectral range. As a rule, three-mirror anastigmats (TMA) are used, however, it is possible to correct four aberrations in some configurations of three-mirror systems without an intermediate image. In order to avoid obscuration, such schemes in a configuration with an off-axis field may be used. In the case of very compact systems, it is necessary to apply fast mirrors, so aspherical surfaces are used. To select the optimal position of an aspherical surface and an equation for describing higher-order and free-form aspherical surfaces, a study is made of higher-order aberrations in systems with various parameters, empirical dependencies are derived that allow one to evaluate the correction capabilities of the schemes. Examples of system designs with an off-axis field are presented.

The influence of UV irradiation on the formation Ag-containing composite and oxide films has been studied. UV irradiation accelerates the formation and growth Ag small molecular clusters and nanoparticles in Ag-containing film-forming solutions, composite and oxide coatings. Photochemical processes and evolution of different structural forms of silver during coatings synthesis were studied by the optical spectroscopy, luminescence methods, SEM analysis. Prepared transparent Ag-containing oxide films containing different structural forms of silver demonstrate high antibacterial activity against bacteria Staphylococcus aureus ATCC 209P.

This paper discuses the problem of reconstructing images in digital form with resolution that exceeds the limiting resolution of a diffraction-limited system from a set of images with spatially modulated illumination. The reconstruction method described here is based on a numerical-analytical solution of the problem of minimizing the mismatch functional of an array of recorded images with their mathematical model. Models of planar and three-dimensional objects are considered, and the effectiveness of the proposed method in computational experiments is demonstrated. By comparison with the classical reconstruction method, the proposed method is distinguished by good stability against deviations of the system parameters from the calculated values, allows the spatial-modulation parameters of the illumination to be automatically estimated, and makes it possible to use a priori knowledge concerning the signal to be reconstructed. Our results can be used when programs are being developed for reconstructing images in structured-illumination microscopy. (C) 2020 Optical Society of America

The article presents the study of the synthesis and characterization of nanostructured transparent ZnO-SnO2 coatings for the intensification of photodecomposition of organic contaminations. Thin transparent coatings were prepared on the glass surface by a polymer-salt method. Mixed oxide coatings were studied by spectroscopic and luminescent methods, SEM, XRD and DSC –TG analysis and their photocatalytic activities were tested. The coatings consist of small closely packed oriented oxide nanocrystals fully covering the substrate surface. Prepared mixed oxide coatings are high transparent in the visible spectral range, able to generate singlet oxygen under UV irradiation and demonstrate photoluminescence and high photocatalytic properties. Simple and low-cost polymer-salt method provides the fabrication homogeneous and transparent photocatalytic oxide coatings significantly accelerating photodecomposition of organic contaminations.

The article presents the study of transparent bactericidal ZnO-SnO2 coatings prepared on a glass surface by a polymer-salt method using polyvinylpyrrolidone, zinc nitrate, and tin (IV) chloride solutions. The coatings were studied by spectroscopic and luminescent methods, SEM, XRD analysis and their antibacterial activities against gram-positive (Staphylococcus aureus ATCC) and gram-negative (Escherichia coli ATCC 25922) were tested. Obtained ZnO-SnO2 films are thin (about 250-300 nm) and they fully cover the glass surface and contain oriented ZnO nanocrystals. Coatings crystal structure strongly affects their spectral and bactericidal properties. SnO(2)additions change the coatings microstructure by decreasing ZnO crystal size and making their spatial orientation more random. These microstructural changes enhance antibacterial activity against gram-positiveand gram-negative bacteria.

Polarimetric studies in astronomy have currently acquired great importance. They are used to study magnetic fields of stars, determine the orientation of orbits of exoplanets, reflection effects in stellar atmospheres and accretion disks, and many other things. This paper presents a computation of optical arrangements of Stokes polarimeters with different polarization analyzers. A preliminary estimate of the transmission of polarimeters with a Wollastone prism and with a modified Foster prism as polarization analyzers is reported. Transmission estimates were performed for different shapes of rectangular output slits and separations between them in two spectral ranges. Recommendations are provided concerning the use of Wollastone and Foster prisms in Stokes polarimeters designed for astrophysical studies.

In this work the photoactive properties of the aqueous suspension containing ZnO nanoparticles and zinc nitrate have been studied. The mechanism of organics photodecomposition at the presence of prepared suspension was studied by the measurements of spectral dependencies of Chicago Sky Blue dye photodecomposition. It was found that dye photodecomposition proceeds in three different photochemical processes: 1) the direct photodecomposition of organic molecules; 2) oxidation of dye molecules by reactive oxygen species which are the product of nitrate anions photodecomposition; 3) photocatalytic action of ZnO nanoparticles.

The system of AR became very popular for educational, military, entertainment and other areas. There are many possible variants of organization the optical part of such schemes. The very important part of the system is a combiner, that is an element which imposes augmented image over the surrounding environment. The power combiner helps to increase the eye relief, but in the case of the tilted power combiner, it adds a rather large amount of off-axis aberrations. These aberrations should be corrected by the following part of the system. Many ways of composing the system with tilted power combiner have been considered and can be found in modern literature. We consider special types of aberrations added by the curved combiner and discuss the ways of the correction. We also analyze possible layouts and their properties for using together with FLCOS and AMOLED microdisplays.

The report presents the results of computer simulation of a polarimetric unit of a high spectral resolution spectrograph with fiber optic input for the 6-m telescope of SAO RAS. The module permits evaluating the polarization state of the incoming radiation. The algorithm of calculation of the instrumental polarization introduced by the BTA main mirror and matching optics of polarimetric unit is based on the Mueller matrices method. The ways of evaluation methods of the degree of polarization, azimuth angle and ellipticity of radiation transmitted through the BTA main mirror and matching optics of polarimetric unit are shown. The obtained results of computer simulation, after comparison with practical data and inevitable insignificant refinements can be taken as a basis for creation of an accurate model of the map of polarization errors introduced by the BTA main mirror and its tools.

Thin bactericidal ZnO coatings prepared with the polymer-salt method are shown to be highly transparent in the visible. The spectral measurements and XRD analysis data show that coatings prepared are formed by ZnO nanoparticles ~ 10 nm in size. The coatings demonstrate the bactericidal effect against the gram-positive Staphylococcus aureus ATCC 209P and gram-negative Escherichia coli ATCC 25922 bacteria both under the natural light and in the darkness.

It is experimentally shown that silver-containing silicate photosensitive glasses can be used for multilevel optical information recording using UV nanosecond laser pulses. Information can be recorded by the creation of luminescent centers, which are neutral silver molecular clusters, or silver nanoparticles with plasmon resonance using additional thermal treatment. It is shown that silver nanoparticles formed in glass have spheroidal shapes and have dielectric shells. Multilevel optical information recording can be performed by modulation of luminescence or absorption intensity varying UV laser irradiation dose. The effect of dopants (Ce, Sb, and Cl) on the recording process is shown. The described methods allow to record optical information in octal and hexadecimal number systems. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)

Recently there is a growing interest to the head up and head mounted systems. There are many variants of implementation of the head-mounted display system for various purposes with different characteristics. The configuration of the system is highly affected by both type of the image generator and the type of the used combiner. We have considered several variants of the layout of the systems and compare their characteristics including the package and image quality. The systems were designed for operating with the same image generator.

Thin and uniform ZnO and ZnO:Al coatings were prepared on glass surfaces by using film-forming colloidal solutions containing small ZnS nanoparticles and polyvinylpyrrolidone as a polymer stabilizer. Film-forming ZnS sols were synthesized in the mixed water-propanol-2 solutions by chemical reaction between zinc nitrate and sodium sulfide. The addition of modifying component such as Al(NO3)(3) into the film-forming solutions allows one to obtain thin and uniform ZnO:Al coatings. An increase in the sodium sulfide content in film-forming solutions leads to the growth of light absorption in the UV. The evolution of a coating material at all technological stages from the ZnS sols up to the transparent ZnO and ZnO:Al2O3 coatings (the latter kind being denoted further, in accord with a common practice, by ZnO:Al) was studied using the optical spectroscopy, XRD analysis, DSC-TGA, and SEM methods. The chemical processes of decomposing salts and the polymer occur by heating the intermediate composite ZnS/ polyvinylpyrrolidone coatings in the 280-500 degrees C temperature range. Experimental data show that the ZnO and ZnO:Al coatings prepared consist of the slightly elongated oxide nanoparticles. These coatings fully cover the glass surface and demonstrate a high transparency in the UV and visible. (C) 2017 Elsevier B.V. All rights reserved.

The paper presents a critical analysis and modernization of separate elements of the optical layout of a high-resolution spectrograph with fiber input for the Big Azimuthal Telescope of the Special Astrophysical Observatory. The modernization is directed mainly at enhancing the light efficiency and making it possible to produce the spectrograph using domestic manufacturers. Renovated versions of the cross-dispersion grism, the projection camera, and the overall characteristics of the system are presented. The resulting efficiency of the whole instrument is given.

After surgical treatment for locally advanced oral tumors with resection of soft tissues, mucosal membrane, and facial skeletal structures, there are penetration combined defects, removal of which is a challenge for reconstructive surgeons. Mandibular repair is one of the problems in the correction of combined oral defects. Surgeons use different grafts to remove mandibular defects. One-flap transplantation does not always solve all reconstruction problems and ensure the repair of the mucosal membrane, a soft-tissue component, skin integuments, and facial skeleton.The authors describe a clinical case of successful single-stage correction of penetration combined orofacial defect after resection of the tongue, mouth floor, en bloc resection of the lower jaw and mental soft tissues, bilateral cervical supramyochoroidal lymphadenectomy, stage LCL CM mandibular defect formation after J. Boyd, by using two microsurgical autografts (a peroneal skin-muscle-skin autograft and a radial skin-fascia one) in a 39-year-old female patient clinically diagnosed with carcinoma of the left mandibular alveolar ridge mucosa, Stage IVA (T4аN0M0).The Department of Microsurgery, P.A. Herzen Moscow Oncology Research Institute, Ministry of Health of Russia, has gained experience in comprehensively correcting extensive combined maxillofacial defects with two or more grafts in 27 patients who underwent autografting with a total of 73 flaps. The most functionally incapacitating and life-incompatible defect was removed at Stage 1 of reconstructive treatment. Delayed reconstruction was made after a complex of specialized antitumor therapy and assessment of treatment results in the absence of progressive growth. A great problem during multi-stage defect correction is presented by the lack of recipient vessels after cervical lymphadenectomy, the presence of soft tissue scar changes, trismus, temporomandibular joint ankylosis, contractures and displacement of the edges of the resected mandible, and autografting into the chronically infected area.Single-stage repair, including that using a few microsurgical autografts, is the operation of choice for adequate anatomic and functional rehabilitation, permits the promptest recovery of patients, reduces a postoperative period, and allows them to undergo an antitumor treatment cycle. However, the repair is possible, when the risk of disease progression is low, in specialized centers and when there are trained head and neck surgery and reconstructive microsurgery specialists and anesthesiologists.

Objective. To minimize surgical trauma in patients with head and neck tumors during microsurgical plasty with visceral autografts.Subjects and methods. Clinical experience has been gained in the treatment of 53 patients with locally advanced craniofascial (n = 27) and oropharyngeal (n = 36) cancers. Abdominal organs were used for plastic closure of extensive defects after surgical resection. Paraumbilical incision allowing for an adequate approach into the abdominal cavity with minimal external trauma in the anterior abdominal wall was chosen as an access procedure. Video-assisted techniques were used to excise the midline aponeurosis. Donor organs, such as the omentum, greater curvature of the stomach, transverse colon, small intestine) were taken through a mini-laparotomic incision to the anterior abdominal wall, then the vascular pedicle was exposed and a visceral autograft was made. After forming and cutting off the autograft, organ anastomoses were created extracorporeally.Results. Mini-access surgery could be completed in 50 of the 53 cases (4 patients had previously undergone abdominal interventions). Omental (n = 26), colo-omental (n = 15), gastro-omental (n = 7), and entero-omental (n = 5) flaps were made and prepared for autografting. No intra- or postoperative abdominal complications were found.Conclusion. Minimally invasive technologies used to create visceral authografts for head and neck tissue repair can minimize surgical trauma and reduce treatment duration. The indications for this access are the debilitating state of a cancer patient or the young age of a patient who does not wish to have an additional scar in the donor region.