Showing papers by "Uzhhorod National University published in 2014"
31 Dec 2014
TL;DR: In this paper, the 60th anniversary of the Urbach rule is dedicated to the analysis of its edge behavior, measured by optical absorption spectroscopy, for different solids.
Abstract: The paper is dedicated to the 60th anniversary of the Urbach rule. The Urbach edge behaviour, measured by optical absorption spectroscopy, is analysed for different solids. The general regularities of the Urbach rule revealed in crystalline and amorphous solids as well as the temperature behaviour of its main parameters are discussed. The main attention is paid to the studies of the possibilities of the Urbach rule parameters to be used for studying disordering processes in solids, short- and medium-range order in amorphous materials, specific features of the Urbach "bundle" in nanosystems and its variation in the vicinity of phase transitions. It is shown that the parameters obtained from the Urbach rule give an important information about dynamic properties of elementary excitations in condensed matter as well as about the interaction of electronic excitations with phonons.
136 citations
TL;DR: The antimicrobial and antifungal activities of two probiotic strains and their 1 : 1 combination, named SYNBIO, were studied using four different methods.
Abstract: Aims
Probiotic lactobacilli have a great potential to produce antimicrobial compounds that inhibit and control the microbial pathogen growth. The antimicrobial and antifungal activities of two probiotic strains, Lactobacillus rhamnosus IMC 501® and Lactobacillus paracasei IMC 502®, and their 1 : 1 combination, named SYNBIO®, were studied using four different methods.
Methods and Results
Using two modified streak methods and a well diffusion method, the inhibitory activity of the probiotics and their metabolites towards six Gram-positive, nine Gram-negative pathogenic bacterial strains and eight Candida strains was tested. Antagonistic effect of probiotic Lactobacillus strains was also investigated by coculturing assay highlighting a significant inhibition of most of the pathogens tested in this study. The combination SYNBIO® showed a microbicidal activity against most of the strains tested in the study.
Conclusions
Compared with the control, most of the pathogenic bacteria and yeast were inhibited by all probiotic strains tested to various degrees.
Significance and Impact of the Study
Screening Lactobacillus strains according to their activity in various environmental conditions could precede the clinical efficacy studies for adjunct treatment with probiotics in cure of different gastrointestinal and vaginal tract infections.
111 citations
TL;DR: In this article, the influence of grain size on the electrical conductivity of 6PS5I superionic ceramics was studied. But the average grain sizes of nanocrystalline powders were not determined.
43 citations
TL;DR: Extended RAS analysis from this study showed a trend toward improvements in HR on OS and PFS with pmab + FOLFIRI vs F OLFIRI in WT RAS group vs WT KRAS exon 2 group.
Abstract: 3568 Background: Previously, extended RAS analysis from this study showed a trend toward improvements in HR on OS and PFS with pmab + FOLFIRI vs FOLFIRI in WT RAS group vs WT KRAS exon 2 group. Her...
39 citations
TL;DR: In this article, two types of amorphous functional materials based on light-sensitive inorganic compounds like Se and As20Se80 chalcogenide glass (ChG) were investigated with the aim to establish the influence of plasmonic fields, excited by the recording light in nanocomposite layers made of these compounds and gold nanoparticles on their photomechanical response.
Abstract: Two types of amorphous functional materials, based on light-sensitive inorganic compounds like Se and As20Se80 chalcogenide glass (ChG) were investigated with the aim to establish the influence of plasmonic fields, excited by the recording light in nanocomposite layers made of these compounds and gold nanoparticles on their photomechanical response. Both these basic materials are characterized by pronounced photoplastic effect and used for real-time optical recording of optoelectronic elements (based mainly on surface relief gratings) due to high photofluidity and polarization-dependent mass-transport. We have established that mass-transport processes in these ChG can be enhanced in the presence of localized plasmonic fields generated by light if the condition of surface plasmon resonance (SPR) is fulfilled. The subjects of special interest are the mass-transport processes at nano-scale stimulated in the nano-composite layers either by uniform or periodically distributed optical fields. It was found that irradiation by light in the presence of SPR really enhanced the efficiency of mass-transport and produced surface nanostructurizations. The variation in the topography follows closely and permanently the underlying near field intensity pattern.
Nanostructurization of photosensitive amorphous As20Se80 film by surface plasmon near field irradiation.
20 citations
TL;DR: In this paper, compositional, frequency, and temperature studies of impedance and electrical conductivity in (Ag3AsS3)x(As2S31−x superionic glasses and composites were performed.
Abstract: Compositional, frequency, and temperature studies of impedance and electrical conductivity in (Ag3AsS3)x(As2S3)1−x superionic glasses and composites were performed. Frequency range from 10 Hz to 3 × 109 Hz and temperature interval 300–400 K were used for the measurements. Compositional dependences of electrical conductivity and activation energy are analyzed; the most substantial changes are observed with the transition from (Ag3AsS3)0.4(As2S3)0.6 glass to (Ag3AsS3)0.5(As2S3)0.5 composite. With increase of Ag3AsS3 content, the investigated materials are found to have crystalline inclusions and show the two-phase composite nature. Addition of Ag3AsS3 leads to the increase of electrical conductivity whereas the activation energy decreases.
14 citations
TL;DR: In this paper, the dielectric and optical properties of TlInS2 single crystal were carried out in the temperature interval 150-300 K and in the hydrostatic pressure range up to 700 MPa.
13 citations
TL;DR: In this article, as-deposited, annealed and illuminated thin films were performed using XRD, scanning electron and atomic force microscopies, and the optical absorption spectra in the region of its exponential behaviour were analyzed, the dispersion dependences of refractive index as well as their variation after annealing and illumination were investigated.
10 citations
TL;DR: In this paper, a profile variation of holographic surface relief gratings is detected in thin (2'μm) As20Se80 chalcogenide films under e-beam irradiation: gratings of small periods were smoothed and increased their amplitudes; the profile variation is mainly caused by competition between capillary forces and "chemical" forces induced by broken and deformed atomic bonds.
Abstract: Unusual profile variation of holographic surface relief gratings is detected in thin (2 μm) As20Se80 chalcogenide films under e-beam irradiation: gratings of small periods were smoothed, whereas the gratings of larger periods increased their amplitudes. Irradiation was carried out in SEM, with 20 kV voltage and 8 nA current; the profiles of the irradiated areas were analyzed both by AFM and SEM. It is found that the kinetics of both flattening and growth followed by exponential law and took place due to lateral mass transport accelerated by e-irradiation. It is shown that the profile variation is mainly caused by competition between capillary forces and “chemical” forces induced by broken and deformed atomic bonds under e-beam irradiation. The kinetics of profile variation was calculated assuming that the mechanism of e-beam induced mass transfer is volume diffusion. The diffusion coefficients were estimated from the experimental data using theoretical expressions derived.
10 citations
TL;DR: In this paper, the formation of complex defect centers related to the N3 center in nanosized diamond by employing plasma immersion and focused ion beam implantation methods was reported. But the defect creation process was performed with the aim of creating carbon atom vacancies in the diamond structure, followed by the introduction of molecular N2+ ion and heat treatment in vacuum at 750°C to initiate vacancy diffusion.
Abstract: This paper reports on the formation of complex defect centers related to the N3 center in nanosized diamond by employing plasma immersion and focused ion beam implantation methods. He+ ion implantation into nanosized diamond “layer” was performed with the aim of creating carbon atom vacancies in the diamond structure, followed by the introduction of molecular N2+ ion and heat treatment in vacuum at 750 °C to initiate vacancy diffusion. To decrease the sp2 carbon content of nanosized diamond formed during the implantation processes, a further heat treatment at 450 °C in flowing air atmosphere was used. The modification of the bonding properties after each step of defect creation was monitored by Raman scattering measurements. The fluorescence measurements of implanted and annealed nanosized diamond showed the appearance of an intensive and narrow emission band with fine structures at 2.98 eV, 2.83 eV, and 2.71 eV photon energies.
10 citations
TL;DR: In this article, the atomic composition, local structure and coordination of flash evaporated Ge2S3 films and their changes induced by laser illumination and thermal annealing in vacuum were investigated by means of high resolution synchrotron radiation and X-ray photoelectron spectroscopy.
Abstract: The atomic composition, local structure and coordination of flash evaporated Ge2S3 films and their changes induced by laser illumination and thermal annealing in vacuum were investigated by means of high resolution synchrotron radiation and X-ray photoelectron spectroscopy. The top surface and subsurface layers of the films are found to be enriched by Ge in comparison with the composition of target glass and contain oxygen and a significant contribution of physisorbed carbon. The influence of laser and thermal treatments of flash evaporated Ge–S films in vacuum on their composition is analyzed. The local atomic coordination obtained by curve fitting of Ge 3d, S 2p, O 1s and C 1s core level spectra is discussed in detail.
TL;DR: In this article, the laser-induced crystallization of SbSI crystallites from the amorphous (As 2 S 3 ) 0.45 (SbSI) 0.55 thin films was observed in micro-Raman measurements as a result of local laser beam heating.
Abstract: (As 2 S 3 ) 0.45 (SbSI) 0.55 thin films were studied by Raman spectroscopy and atomic force microscopy. Laser-induced crystallization of SbSI crystallites from the amorphous (As 2 S 3 ) 0.45 (SbSI) 0.55 thin films was observed in micro-Raman measurements as a result of local laser beam heating. The dependence of the observed effect on the laser power and the film pre-heating duration is discussed. No such effects were observed for bulk glasses with a similar composition.
TL;DR: The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal.
Abstract: The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal. The results of calculations are presented that are verified experimentally with Sn2P2S6.
TL;DR: X-ray diffraction studies of Cu 6 AsS 5 I crystals grown using the chemical vapor transport method are performed in this article, where complex electrical conductivity, impedance, dielectric permittivity, and electrical modulus of the crystal are studied in wide frequency range and temperature interval from 100 to 400 K.
TL;DR: In Czechoslovakia, the Uniate Church recorded outflow faithful to the Orthodox Church, by almost 5% (from nearly 55% to 50.2%) and Orthodox increase by approximately the same proportion over 15% of the population as discussed by the authors.
Abstract: The issues and religious disputes in Carpathian Ruthenia in Czechoslovak period and its echoes behind the Atlantic In Subcarpathian Ruthenia in the interwar period – during her membership in Czechoslovakia, one of the sharper conflict was a dispute between two Christian churches. In fact, the rivalry of the two churches began even earlier, during the Hungarian reign – before 1918, but broke out with the new intensity in the interwar period. The Czech authorities, retained neutrality in the confessional disputes, unlike its predecessors, favoring the units. The dispute also had political significance – namely in the conflict between national orientations: Russophile and Ukrainian. Both churches were not monoliths and shook them as internal tensions, including politically motivated ones. Religious conflicts had also their roots and echoes on the other side of the Atlantic. Part of the Greek-Catholic immigrants Transcarpathian did not want to submit to the American Catholic hierarchy, who failed to see the specifics of this group of emigrants. During the period between the Uniate Church recorded outflow faithful to the Orthodox Church, by almost 5% (from nearly 55% to 50.2%) and Orthodox increase by approximately the same proportion – over 15% of the population. Kwestie i spory religijne na terenie Rusi Zakarpackiej w czechoslowackim epizodzie jej dziejow Na Rusi Zakarpackiej w okresie miedzywojennym, podczas jej przynalezności do Czechoslowacji, jednym z ostrzejszych konfliktow byl spor pomiedzy dwoma chrześcijanskimi Kościolami. Faktycznie rywalizacja dwoch Kościolow zaczela sie wcześniej, za rządow wegierskich – przed 1918 rokiem, ale rozgorzala z nową intensywnością w okresie miedzywojennym, kiedy wladze czeskie, zachowywaly neutralnośc w tych konfesyjnych sporach, w przeciwienstwie od poprzednikow, faworyzujących unitow. Spor mial takze aspekt polityczny – ocierając sie o konflikt miedzy orientacjami narodowymi: ukrainską i rosyjską. Oba Kościoly nie byly monolitami i wstrząsaly nimi takze wewnetrzne napiecia, w tym na tle politycznym. Konflikty na tle religijnym mialy tez swoje zaoceaniczne korzenie i echa, gdzie cześc grekokatolickich emigrantow zakarpackich nie chciala sie podporządkowac amerykanskiej hierarchii katolickiej, nie dostrzegającej specyfiki tej grupy wychodźcow. Podczas okresu miedzywojennego Kościol unicki odnotowal odplyw wiernych na rzecz prawoslawia, o prawie 5% (z prawie 55 do 50,2%), a Cerkiew Prawoslawna przyrost o mniej wiecej o ten sam odsetek – do ponad 15% mieszkancow.
26 May 2014
TL;DR: Formation of fragments of both low- and high-temperature α-, β-GeS2 crystalline phases in the structure of g- GeS 2(TiVj) glasses indicates the existence of mixed medium-range ordering in g-Ge S2.
Abstract: Technologically modified g-GeS 2 (TiVj) glasses prepared by melt quenching from different temperatures (T i ) and with different cooling rates (Vj) were studied using Raman spectroscopy and model calculations. Differential Raman spectra {I R GeS 2 (T i V 1 )-I R GeS2(T 2 V 1 )} showed the splitting of the main, most intensive wide-band, centered at 340 cm -1 . The position of the peaks found in the differential Raman spectra near 340 and 360 cm -1 and position of the main vibrational modes in the ordinary Raman spectra of low- and high-temperature crystalline phases (α-, β-GeS2) were found to be in good agreement. Vibrational spectra of 4- and 6-member ring fragments selected from crystalline structure of β-GeS 2 were also determined using model calculations. Based on rings composed of GeS 4 tetrahedrons connected by corners and edges the structural interpretation of the vibrational bands of g-GeS 2 (TiVj) at 360, 370 and 433 cm -1 in their Raman spectra was performed. The existence of homopolar Ge-Ge and S-S “defect” bonds in the structure of germanium disulfide glasses was proved by formation of 5-member rings. Formation of fragments of both low- and high-temperature α-, β-GeS 2 crystalline phases in the structure of g-GeS 2 (TiVj) glasses indicates the existence of mixed medium-range ordering in g-GeS 2 .
TL;DR: In this article, anomalous absorption of light beyond the fundamental absorption edge of the semiconductor is observed, caused by the interaction of the near field of surface plasmons in metal nanoparticles with interference (virtual) modes of the Fabry-Perot cavity formed by semiconductor film.
Abstract: In Au/As2S3 metal-semiconductor surface composite structures, anomalous absorption of light beyond the fundamental absorption edge of the semiconductor is observed. This absorption is caused by the interaction of the near field of surface plasmons in metal nanoparticles with interference (virtual) modes of the Fabry-Perot cavity formed by the semiconductor film.
TL;DR: Clinical trials had been performed in order to detect the early microbial and immunological biomarkers and efficacy of polyphenols reach extracts effect on CVD functions.
Abstract: Materials and methods Classic and modern experimental systems, animal and cells models in preclinical investigation had been used. Methanolic extracts of edible plants: nettle, dill, kale, persimmon, pomegranate, and Sideritis scardica were administered to mice orally for two weeks (15 mg/200μl/day/ mouse). Level of IgAs in gut contents and cytokine profiles in supernatants of fragment cultures of gut associated lymphoid tissues was measured by ELISA, and numbers of immune cells quantified by FACS. Human DCs derived from peripheral blood monocytes were exposed to plant extracts at 2 mg/ml for 6 and 24 hours. The expression of CD markers by DCs and levels of secreted cytokines were assessed before and after exposure to the extracts. Clinical trials had been performed in order to detect the early microbial and immunological biomarkers and efficacy of polyphenols reach extracts effect on CVD functions.
TL;DR: This work considers the estimation of the accuracy and computational complexity of the combined s-algorithm of the separation of all the solutions in a given bounded domain and their iterative correction up to the required accuracy in the approximate computational solution to multiextremum problems of global optimization of twice continuously differentiable functionals.
Abstract: We consider the estimation of the accuracy and computational complexity of the combined s-algorithm of the separation of all the solutions in a given bounded domain and their iterative correction up to the required accuracy in the approximate computational solution to multiextremum problems of global optimization of twice continuously differentiable functionals.