The Ricci flow on generalized Wallach spaces

We consider the asymptotic behavior of the normalized Ricci flow on generalized Wallach spaces that could be considered as special planar dynamical systems. All non symmetric generalized Wallach spaces can be naturally parametrized by three positive numbers $a_1, a_2, a_3$. Our interest is to determine the type of singularity of all singular points of the normalized Ricci flow on all such spaces. Our main result gives a qualitative answer for almost all points $(a_1,a_2,a_3)$ in the cube $(0,1/2]\times (0,1/2]\times (0,1/2]$.Comment: 18 pages, 3 figures, comments are welcom

Neural network analysis of hyperspectral images of soil

The article approaches to the classification of high-resolution hyperspectral images in the problem of classification of soil species is proposed. A spectral-spatial convolutional neural network with compensation for lighting variations is used as a classifier. The effectiveness of the proposed approach in the problem of classification of hyperspectral images of soils obtained by a scanning hyperspectral camera is shown. The essence of the developed method is to use binary classification together with multiclass, thereby improving the result of the latter

Hyperspectral images neural network analysis of unstained micropreparations

The article presents the results of a study of hyperspectral imaging in microscopy to assess pathological changes in unstained medical micropreparations.Hyperspectral imaging was carried out using a system of synchronous shooting and movement of a movable table combined with a stepper motor. To improve the quality of theobtained images, software correction of the illumination of the spectral channels was used. The classification was carried out by a convolutional neural network. This method may be promising for assessing pathological changes in clinical practice. Experimental studies were carried out on histological preparations with different types of tissues without staining with contrasting medical dyes. To assess the reliability of the classification method, a comparison was made with thestandard method using staining of the studied samples

The effect of the Ti (IV)-citrate complex on Staphylococcus aureus growth and biofilm formation

The primary objective of this study was to investigate the influence of the Ti (IV)-citrate complex on growth dynamics and biofilm formation of S. aureus. Speciation analysis was performed in order to estimate the structure of the Ti complex existing in citrate solutions at near-physiological pH. It is estimated that the fully deprotonated tris(citrate) titanate ion [Ti(C6H4O7)3]8- predominates in solution at pH 6.46-7.44, and that this is most probably the biologically active form of Ti(IV)-citrate. In in vitro experiments, increasing concentrations of citric acid solutions (0.05, 0.005, 0.0005 M), served as positive controls, while the effects of respective concentrations of Ti(IV)-citrate were examined. The obtained results indicate that citrate decreased S. aureus 48 growth at all studied concentrations, whereas S. aureus 44 growth was decreased only by high concentrations of citrate (0.05M). Incubation of S. aureus culture with Ti(IV)-citrate significantly potentiated citrate-induced effects. Ti(IV)-citrate significantly altered specific bacterial growth rate in a similar manner. The most significant growth reduction was observed at the initial period of bacterial growth. At the same time, the opposite effect was detected in investigations of the effect of citrate and Ti(IV)-citrate on S. aureus biofilm formation. Citric acid suppressed S. aureus biofilm formation, whereas Ti(IV)-citrate displayed a significant stimulatory effect. Our findings suggest that Ti(IV)-citrate possesses a more pronounced biological effect than citrate. The proposed mechanism of this action is activation of complex transport into the cell and induction of oxidative stress. However, the exact mechanism of Ti(IV)-citrate biological action on bacterial cultures remains unknown

PREVENTIVE ZINC SUPPLEMENTATION EFFECT ON REDOX STATUS IN RAT MODEL OF MAFLD

Background. Oxidative stress plays an important role in the pathogenesis of metabolic-associated fatty liver disease (MAFLD). Antioxidant trace elements as cofactors of antioxidant enzymes and metalloproteins are involved in this process. Zinc being an important antioxidant may have a positive effect on the treatment of liver pathology. The study aimed to assess the effect of preventive zinc supplementation on MAFLD in rats. Materials and Methods. A total of 26 three-month-old female Wistar rats were used in the present study. The activity of the antioxidant enzymes superoxide dismutase and catalase, some redox status markers, such as ceruloplasmin, oxidized tryptophan, dithyrosines, total thiols, carbonyls, TBARS, and uric acid were evaluated. Oxidative stress biomarkers were studied spectrophotometrically. Results. MAFLD was accompanied by hyperuricemia and a decrease in serum dityrosines. The addition of Zn to the diet prevented the development of steatosis, decreased the level of oxidized tryptophan in the liver, and paradoxically caused hyperuricemia in the MAFLD model used. Zn supplementation had a positive effect on the prevention of MAFLD, had a little effect on redox status of animals but caused paradoxical hyperuricemia. Future studies are needed to establish the mechanisms of the Zn effect at the cellular level

http://ntv.ifmo.ru/file/article/10373.pdf

Comparative analysis of spectral and luminescent properties for glasses SiO2-Al2O3-MgO-K2O-TiO2 doped with chromium ions and forsterite nano-glass ceramic have been done. Initial glasses were obtained by using a conventional melt quenching method. Glass ceramics were produced by the two-stage secondary heat treatment of initial glasses. At the first step of the heat treatment nucleation centers were formed at 700º C. At the second step there was an increase of Mg2SiO4: Cr crystalline phase. Crystalline phase composition and the crystals size were determined by X-ray diffractometer. It is shown that the crystalline phase of Mg2SiO4 (forsterite) is precipitated during the heat treatment. Valency state and the chromium ion position in a forsterite or a glassy matrix are determined according to luminescence and absorption spectra. Identification of absorption and luminescence bands in initial and heat-treated samples is carried out. The dependence between spectral and luminescent properties of chromium and heat treatment modes is examined. The results demonstrate that ions of the trivalent and tetravalent chromium are transforming to the forsterite crystalline phase during the heat treatment, and a part of them remains in the glassy phase. Presented research results can be used for the development of glasses and nanoscale glassceramic for fiber tunable lasers and broadband optical amplifiers of a near infrared range which are used in information and telecommunication technologies

Polarity and structure of 2-(1-methylbenzimidazol-2-yl)-1-phenyl- and -1,2-diphenyl-1-nitroethenes

Polarity of 2-(1-methylbenzimidazol-2-yl)-1-phenyl- and -1,2-diphenyl-1-nitroethenes was determined and their structure was studied using electronic and 1H, 13C NMR spectroscopy, dipole moments measuring, XRD analysis, and quantum-chemical calculations. It was shown that the 2-(1-methylbenzimidazol-2-yl)-1-nitro-1-phenylethene has Z-configuration both in crystal and solution. The nitro group and benzimidazole substituent in its molecule are removed from the plane of the double bond. For 1,2-diphenyl-1-nitroethene E-structure is typical. © 2012 Pleiades Publishing, Ltd