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The influence of oxygen content in active zirconium oxide layers on the electrophysical properties of TaN/ZrOx/Ni memristors is investigated. The [O]/[Zr] atomic ratio (x) in the oxide layers was varied in the range from 1.56 to 2.0 by changing the partial oxygen pressure during their deposition by ion-beam sputtering deposition. The ZrOx film compositions were analyzed using x-ray photoelectron spectroscopy and density functional theory simulations. The multiple resistive switching phenomenon in TaN/ZrOx/Ni memristors was found to occur in a certain range of x ≥ 1.78. With the x value decreasing in the oxide layers, the forming voltage of memristors decreased. Furthermore, at the lower edge of x values the switchable range, they no longer required forming. At the same time, as the x value decreased, the memory window (ION/IOFF ratio) also decreased from 5 to 1 order of magnitude due to an increase in the memristor conductivity in the high resistance state. In order to identify the underlying conduction mechanism of TaN/ZrOx/Ni memristors, their current–voltage curves in low and high resistance states were analyzed in the temperature range from 250 to 400 K for the samples with x = 1.78 (forming-free) and 1.97 (which required forming). It was found that, for both samples, the conductivity in the low-resistance state is characterized by the trap-free space-charge-limited current (SCLC) model, whereas the conductivity in the high-resistance state is characterized by the trap-mediated SCLC model. The possible origins of structural defects involved in the memristor conductivity and resistive switching are discussed based on the obtained results. [ABSTRACT FROM AUTHOR]

The results of stochastic resonance investigation in a nonlinear system, consisting of a microstructure with a polycrystalline vanadium dioxide (VO2) film grown on sapphire and resistor in series are reported. Nonlinearity of the system was provided due to insulator-metal phase transition in VO2. In the stochastic resonance regime at 100 Hz signal frequency, the transition coefficient of signal-to-noise ratio reached 87 in contrast to 250 for microstructures with VO2 films grown on silica in our previous investigations. The measured characteristics of microstructures with VO2 films grown on silica and sapphire substrates were found to be qualitatively similar. For both substrates, a stochastic resonance was observed at threshold switching voltage from insulating to metallic state of VO2. For sapphire substrate the output signal-to-noise ratio rose at higher signal frequencies. The stochastic resonance phenomenon in VO2 films is explained in terms of the monostable damped oscillator model. [ABSTRACT FROM AUTHOR]

A study of how the partial substitution of Bi with Pb impacts the mechanism of excess conductivity in a Bi-Sr-Ca-Cu-O system. It is found that such a substitution leads to an increase in the critical temperature of the Bi1.7Pb0.3Sr2Ca2Cu3Oy(B2) sample, in comparison to Bi2Sr2CaCu2Ox (B1) [Tc (B2) = 100.09 K and Tc (B1) = 90.5 K, respectively]. At the same time, the resistivity ρ of the sample B2 in the normal phase decreases by almost 1.5 times in comparison to B1. The mechanism responsible for the generation of excess conductivity in cuprate HTSCs Bi2Sr2CaCu2Ox and Bi1.7Pb0.3Sr2Ca2Cu3Oy is examined using the local pair model with consideration of the Aslamazov-Larkin theory, near Tc. The temperature T0 of the transition from the 2D fluctuation region to the 3D (i.e., the temperature of the 2D-3D crossover), is also determined. The coherence length ξc(0) along the c axis of fluctuation Cooper pairs is calculated. It is shown that the partial substitution of Bi with Pb in the Bi-Sr-Ca-Cu-O system leads to a decrease in ξc(0) by a factor of 1.3 (4.205 and 3.254 Å, respectively), and that there is a narrowing of both the region of pseudogap existence and the region of superconducting fluctuations near Tc. The temperature dependence of the pseudogap Δ*(T) and the value Δ*(Tc) are determined, and the temperatures Tm, which correspond to the maximum of the pseudogap as a function of temperature in these materials, are estimated. The pseudogap maxima in samples B1 and B2 are found to be 61.06 and 38.18 meV, respectively. [ABSTRACT FROM AUTHOR]

We examine the effect of replacing calcium by zinc has on the transport properties of the BiSrCaCuO-2221 system. It is shown that the critical temperatures Tc of the Bi2Sr2CaCu2Ox(B1) and Bi2Sr2ZnCu2Oy(B2) samples are close (81K and 80.72 K). However, the resistivity ρ of the Bi2Sr2ZnCu2Oy sample increases considerably, and the ratio ρB2/ρB1≈10 at 100 K. We use the local pair model to analyze the mechanism behind the formation of excess conductivity in Bi2Sr2CaCu2Ox and Bi2Sr2ZnCu2Oy(B2), with consideration of the Aslamazov-Larkin theory near Tc. We determined the temperature T0 of the transition from the 2D fluctuation area to the 3D region (i.e., the 2D-3D crossover temperature). We calculated the coherence length of the fluctuation Cooper pairs along the c axis, ξc(0). It is shown that substituting Zn for Ca reduces ξc(0) by almost 1.5 times (4.8 Å and 3.3 Å, respectively), and also leads to a narrowing of both the pseudogap region and the superconducting fluctuation area near Tc. We determined the temperature dependence of the pseudogap Δ*T and Δ*(Tc). The increase of ρ, its specific temperature dependence and the significant decrease of T* in sample B2, all point to the destruction of local pairs at all high temperatures, i.e., to the suppression of the pseudogap by Zn doping. [ABSTRACT FROM AUTHOR]

Amorphous nonstoichiometric ZrO films of different composition have been synthesized by the method of ion-beam sputtering deposition of metallic zirconium in the presence of oxygen at different partial oxygen pressures in the growth zone, and their optical properties have been studied in the spectral range of 1.12-4.96 eV. It is found that light-absorbing films with metallic conductivity are formed at the partial oxygen pressure below 1.04 × 10 Pa and transparent films with dielectric conductivity are formed at the pressure above 1.50 × 10 Pa. It is shown that the spectral dependences of optical constants of ZrO films are described well by the corresponding dispersion models: the Cauchy polynomial model for films with dielectric conductivity and the Lorentz-Drude oscillator model for films with metallic conductivity. [ABSTRACT FROM AUTHOR]

Low-frequency (∼2 Hz) current self-oscillations were first obtained in a millimeter-sized two-terminal planar device with a vanadium dioxide (VO2) film. The film temperature distribution dynamics was investigated within one oscillation period. It was established that the formation and disappearance of a conductive channel occur in a film in less than 60 ms with oscillation period 560 ms. The experimentally observed temperature in the channel region reached 413 K, being understated due to a low infrared microscope performance (integration time 10 ms). The VO2 film temperature distribution dynamics was simulated by solving a 2D problem of the electric current flow and heat transfer in the film. The calculation showed that the thermally initiated resistance switching in the film occurs in less than 4 ms at a channel temperature reaching ∼1000 K. The experimental results and simulation are consistent with the current self-oscillation mechanism based on the current pinching and dielectric relaxation in the VO2 film at the metal-insulator phase transition. [ABSTRACT FROM AUTHOR]

Analyzed is the risk of floods under conditions of the isolation of the riverbed from the floodplain on the Lower Kura River. Along with the high sinuosity of the riverbed causing the turbulent nature of the flow, the high concentration of tractional load, the low slope of the riverbed, and the alluvial type of the soil that underlies the riverbed and embankment dams form prerequisites for the intense vertical and horizontal dynamics of the riverbed. [ABSTRACT FROM AUTHOR]

The temperature dependence of electrical capacitance of planar microstructures with vanadium dioxide (VO2) film near the insulator-metal phase transition has been investigated at the frequency of 1 MHz. Electrical capacitance measurements of the microstructures were performed by the technique based on the using of a two-terminal resistor-capacitor module simulating the s108 layer behavior at the insulator-metal phase transition. At temperatures 325-342 K, the anomalous increase in microstructures capacitance was observed. Calculation of electric field in the microstructure showed that VO2 relative permittivity (e) reaches s108 at the percolation threshold. The high value of e can be explained by the fractal nature of the interface between metal and insulator clusters formed near the insulator-metal phase transition. [ABSTRACT FROM AUTHOR]

The origin of a blue luminescence band at 2.7 eV and a luminescence excitation band at 5.2 eV of hafnia has been studied in stoichiometric and non-stoichiometric hafnium oxide films. Experimental and calculated results from the first principles valence band spectra showed that the stoichiometry violation leads to the formation of the peak density of states in the band gap caused by oxygen vacancies. Cathodoluminescence in the non-stoichiometric film exhibits a band at 2.65 eV that is excited at the energy of 5.2 eV. The optical absorption spectrum calculated for the cubic phase of HfO2 with oxygen vacancies shows a peak at 5.3 eV. Thus, it could be concluded that the blue luminescence band at 2.7 eV and HfOx excitation peak at 5.2 eV are due to oxygen vacancies. The thermal trap energy in hafnia was estimated. [ABSTRACT FROM AUTHOR]

Long-lived minima are detected at Tmin1 = 275 K and Tmin2 = 252 K in the ρ(T) curve of polycrystalline CdBa2Cu3O7-δ, which has a superconducting transition at 86.8 K. It is shown that the excess conductivity Δσ(T) near Tmin obeys the classical Aslamazov-Larkin fluctuation theory. This suggests that fluctuation Cooper pairs may develop in CdBa2Cu3O7-δ at T > Tc. The experimental data are used to calculate the coherence length ξc(0), the 2D-3D crossover temperature T0, and the interplanar pairing constants. The magnitude and temperature dependence of the pseudogap for a sample without the minima are found to be typical of cuprate HTSC materials. [ABSTRACT FROM AUTHOR]

The influence of an intense electron beam on a nonstoichiometric oxide HfOx () layer of a TaN/HfOx/Ni memristor on its electrophysical properties is studied. It is found that the crystalline h-Hf, m‑HfO2, o-HfO2, and t-HfO2 phases are formed in the HfOx film under this impact. It is established that memristors demonstrate resistive switching at certain electron fluence values. At the same time, such memristors have resistive switching voltages several times lower than those of unirradiated memristors. In addition, they exhibit a multiple decrease in the spread of resistive switching voltages, as well as resistances in low- and high-resistance states. The current–voltage curves of the obtained memristors indicate that the charge transport in them is described by the space-charge-limited current mechanism. [ABSTRACT FROM AUTHOR]

The phenomenon of stochastic resonance with an input signal gain of 1.6 times was observed in the planar structure that is connected in series with the loading resistor and has a VO conducting channel. It was shown that the signal-to-noise ratio transferring in the circuit can reach 250 times. [ABSTRACT FROM AUTHOR]

Amorphous zirconium oxide (a-ZrO2) thin films were prepared onto fuzzed quartz substrates by ion beam sputtering deposition (IBSD) method in (Ar +O2) gas mixture. Optical parameters of the films were evaluated by laser ellipsometry (λ = 632.8 nm) and optical transmission measurements. Structural parameters were studied by XRD measurements. Variation of refractive index and film thickness have been defined as a function of time of high-temperature annealing at T = 900°C. Formation of monoclinic zirconium oxide (m-ZrO2) nanocrystals with diameter of ~60 nm embedded into a-ZrO2 matrix has been found by XRD analysis after long-time annealing. [ABSTRACT FROM AUTHOR]

A new superconducting ceramic material CdBa2Cu3O7-δ is obtained. It is found that the superconducting transition (at 86 K) is retained when yttrium is fully replaced by cadmium in the Y-Ba-Cu-O system. X-ray diffraction studies show that the crystalline structure is unchanged and the identified peaks coincide when Y is replaced by Cd in YBa2Cu3O7-δ. Besides a stable superconducting transition, a phase transition near 275 K was seen in the temperature dependence of the specific resistivity which shifted toward lower temperatures (252 K) and then disappeared completely over repeated measurement cycles. The thermal conductivity k of YBa2Cu3O7-δ and CdBa2Cu3O7-δ was found to vary little with temperature up to the superconducting transition. Substituting Cd for Y in the initial HTSC material led to a substantial increase in the lattice thermal conductivity. Measurements of the thermal emf showed that it is positive in YBa2Cu3O7-δ and negative in CdBa2Cu3O7-δ. [ABSTRACT FROM AUTHOR]

The electronic structure of an oxygen vacancy in α-AlO and γ-AlO is calculated. The calculation predicts an absorption peak at an energy of 6.4 and 6.3 eV in α-AlO and γ-AlO, respectively. The luminescence and luminescence excitation spectra of amorphous AlO are measured using synchrotron radiation. The presence of a luminescence band at 2.9 eV and a peak at 6.2 eV in the luminescence excitation spectrum indicates the presence of oxygen vacancies in amorphous AlO. [ABSTRACT FROM AUTHOR]

Two-person multistage game with fixed sequence of moves is considered, under perfect information on existing history of the game and aggregated information on the current move of player 2. Having this information at each stage i, player 1 is the first to choose his move x(in1)(.); moreover, in the beginning of the game player 1 announces his strategy x(.)=(a(in1)(.),..., x(in)(.)) for n future stages. Given information regarding the choice of player 1 and history of the game, player 2 strives to maximize his payoff function via the strategy v=(v(in1), v(in2),..., v(inn)). In this paper the sufficient conditions of perfect aggregation, involving certain results from the theory of Lie groups, are provided for the game in question. [ABSTRACT FROM AUTHOR]

The photopolymerization of thin (monolayer and bilayer) Langmuir-Blodgett films of the lead salt of 2-docosynoic acid (CH3(CH2)18C≡CCOOH, DCA), with a triple bond near the carboxylic group, and the lead salt of 23-tetracosynoic acid (HC≡C(CH2)21COOH, TCA), with a triple bond far from the carboxyl group, has been investigated by IR spectroscopy. The principal distinctions between the polymerization kinetics of the DCA salt and that of the TCA salt are observed for bilayers. It is hypothesized that the perfection of the molecular packing in the bilayers is governed by the interlayer interaction of carboxyl groups, which exerts a stronger effect on the mutual orientation of the triple bonds in the DCA salt films as compared to the TCA salt films. A model is suggested for describing the kinetics of the two-dimensional photopolymerization of monoacetylenic compounds. A comparison between simulated and experimental data for the monolayer films demonstrates that the observed saturation of conversion (α) as a function of the UV exposure time ( t) at the α ≈ 0.5−0.6 level can be attributed to the fact that the intermolecular distance lengthens with local film densification during polymerization. The effects of the substrate and the orientation of molecules in the layer on α ( t) is reported. [ABSTRACT FROM AUTHOR]

Single crystals of rare-earth analogs of the mineral krupkaite, CuPbBi3S6, have been prepared for the first time, and their physicochemical properties have been studied. The compounds CuYbBi3S6, CuEuEr3S6, CuYbEr3S6, and CuPbEr3S6 are isostructural with CuPbBi3S6 and crystallize in orthorhombic symmetry (sp. gr. Pb21 m, Z = 2): a = 11.204, b = 11.376, c = 3.960 Å (CuYbBi3S6); a = 11.244, b = 11.440, c = 3.998 Å (CuEuEr3S6); a = 11.30, b = 11.55, c = 4.03 Å (CuPbEr3S6); a = 11.236, b = 11.414, c = 3.98 Å (CuYbEr3S6). [ABSTRACT FROM AUTHOR]

A many-step two-person game is studied with a fixed sequence of moves under aggregated information on every move at the decision making instant and on the choice of player 2 at the current move. Player 1, knowing this information at every stepi, first chooses a strategy xi(·) = (x1(·),...,xn(·)),i=, and informs it fornmoves to player 2 at the beginning of the game. His maximal guaranteed result and the corresponding optimal (?-optimal) strategy are determined. Such games under complete (nonaggregated) information are formulated and a compact expression for the strategy of player 1 is derived. [ABSTRACT FROM AUTHOR]

The composition of synthesized ceramic samples is investigated by x-ray phase analysis, and it is established that they are high-Tc superconducting Bi2Sr2ZnCu2Ox. It is found that the crystal structure is preserved. To investigate how the superconductivity of Bi–Sr–Ca–Cu–O is influenced by the substitution of calcium by zinc, measurements of the temperature dependence of the resistivity, thermal conductivity, and thermopower (Siebeck coefficient) are carried out. It is found that the substituted compound Bi2Sr2ZnCu2Ox retains its superconducting properties (T0=82 K). It is shown that substitution of Ca by Zn leads to an increase of the thermal conductivity. While the thermopower of Bi2Sr2CaCu2Ox shows p-type conductivity in the whole range of temperatures investigated, in Bi2Sr2ZnCu2Ox the type of the conductivity is changed to n-type. [ABSTRACT FROM AUTHOR]

Currently, a new generation of high-speed, information-intensive resistive memory based on nonstoichiometric dielectrics is being developed. The electron structure of nonstoichiometric silicon oxide SiOx is set by the value of parameter x. It is found that the treatment of thermal SiO2 in hydrogen plasma electron cyclotron resonance leads to the enrichment of silicon oxide with excess silicon, which in turn leads to the appearance of electron and hole traps in SiOx. SiOx conductivity is bipolar: electrons are injected from negatively biased silicon and holes are injected from positively biased silicon. Cathodoluminescence (CL) experiments confirm the assumption that the traps in SiOx are due to the excess silicon. p++-Si(100)/SiOx/Ni memristor metal-dielectric-semiconductor (MDS) structures are fabricated based on the developed procedure for the preparation of nonstoichiometric oxide in hydrogen plasma of electron cyclotron resonance. Such structures have the properties of resistive switching of SiOx that do not require a forming operation. [ABSTRACT FROM AUTHOR]

The luminescence spectra of non-stoichiometric zirconium oxide film series with different oxygen vacancies' concentrations show the blue photoluminescence band centered near a 2.7 eV peak. There is a broad band at 5.2 eV in the luminescence excitation spectrum for blue emission. The ab-initio quantum-chemical calculation gives a peak in the optical absorption at 5.1 eV for the oxygen vacancy in cubic ZrO2. It was concluded that the 2.7 eV blue luminescence excited near 5.2 eV in a zirconium oxide film is associated with the oxygen vacancy. [ABSTRACT FROM AUTHOR]

The silicon oxide thin films obtained by thermal SiO2 treatment in hydrogen electron cyclotron resonance plasma at various exposure times are investigated. Using X-ray photoelectron spectroscopy, we have established that such treatment leads to a significant oxygen depletion of thermal SiO2, the more so the longer the treatment time. The atomic structure of the SiOx< 2 films obtained in this way is described by the random bonding model. The presence of oxygen vacancies in the plasma-treated films is confirmed by comparing the experimental valence band photoelectron spectra and those calculated from first principles, which allows the parameter x to be estimated. We show that thermal silicon oxide films treated in hydrogen plasma can be successfully used as a storage medium for a nonvolatile resistive memory cell. [ABSTRACT FROM AUTHOR]

The optical properties and composition of thermal silicon oxide thin films processed in a hydrogen electron cyclotron resonance plasma have been studied by ellipsometry, quantum-chemical modeling, and photoluminescence spectroscopy. It has been found that the plasma processing of the films leads to their oxygen depletion and the formation of nonstoichiometric oxide SiOx< 2. The parameter x of the obtained SiOx films has been determined by comparing the experimental spectral dependence of the refractive index with the dependence obtained theoretically using the ab initio calculation. It is shown that an increase in the time of processing of thermal dioxide SiO2 in a hydrogen plasma leads to an increase in the refractive index of the film, as well as in the degree of its oxygen depletion. The dependence of the parameter x of the investigated films on the hydrogen plasma processing time is plotted. [ABSTRACT FROM AUTHOR]

Lead phthalocyanine (PbPc) thin films deposited by vacuum sublimation with Ar low-temperature electron cyclotron resonance (ECR) plasma treatment are investigated by means of reflection high-energy electron diffraction, atomic force microscopy, infrared spectroscopy, x-ray photoelectron spectroscopy and spectral ellipsometry. The intensity of plasma treatment is varied by the radio-frequency power input and the value of electrical bias applied to the sample. The films grown with and without plasma assistance are compared. The plasma intensity is considered to significantly influence the crystalline structure, surface morphology and film composition. At a low intensity the plasma assistance is analogous to vacuum annealing of films. At a medium intensity, a porous polymer matrix filled with PbPc in crystalline phases (monoclinic and triclinic) is formed in the films. At a high intensity, all the films consist of a compact polymer matrix, similar to a glassy solid, with small inclusions of PbPc molecules. The succession of PbPc molecule destructions in the growing film layer with plasma intensity increase is established by IR spectroscopy. The mechanism of polymer matrix formation is suggested. [ABSTRACT FROM AUTHOR]

The electronic structure of a TaO insulator with oxygen vacancies is studied theoretically and experimentally. The ab initio calculations of δ-TaO are performed in terms of density functional theory using the generalized gradient (GGA) and GGA + U approximations. The electronic structure of TaO is experimentally studied by X-ray photoelectron spectroscopy (XPS). To study oxygen vacancies, an amorphous TaO film is irradiated by argon ions. The calculated XPS spectra of the valence band of δ-TaO agree satisfactorily with the corresponding experimental spectra of the amorphous films. The oxygen vacancy in δ-TaO is found to be a trap for holes and electrons. The minimum and maximum effective masses of electrons and holes in δ-TaO are calculated. [ABSTRACT FROM AUTHOR]

It is shown that the treatment of stoichiometric HfO2, which is synthesized by atomic layer deposition, in electron cyclotron resonance hydrogen plasma leads to a significant depletion of the film in oxygen and the formation of nonstoichiometric HfOx (). The longer the treatment time, the higher the degree of oxygen depletion. The charge transfer in the films under study occurs by phonon-assisted tunneling between oxygen vacancies serving as traps. It has been found that the -Si/HfOx/Ni structures, where the oxide layer is treated in the electron cyclotron resonance hydrogen plasma, have memristor properties: they are reversibly switched between high and low resistance states. The fabricated memristor structures are forming-free. [ABSTRACT FROM AUTHOR]

A study of the influence of magnetic field on the thermal conductivity of Bi2Sr2CaCu2Ox is made. It is found that the thermal conductivity increases under the influence of magnetic field because the electronic part of the thermal conductivity increases on account of breaking of the Cooper pairs and a decrease of the phonon-vortex scattering. [ABSTRACT FROM AUTHOR]

Optical properties of amorphous nonstoichiometric tantalum-oxide films of variable composition (TaOx, x = 1.94-2.51) in the spectral range of 1.12-4.96 eV, obtained by ion-beam sputtering-deposition of metallic tantalum at different partial oxygen pressures (0.53-9.09 × 10-3 Pa), have been investigated. It is shown by spectral ellipsometry that the character of dispersion of the absorption coefficient and refractive index in TaOx of variable composition suggests that light-absorbing films with dispersion similar to that in metals are formed at oxygen pressures in the growth chamber below 2.21 × 10-3 Pa, whereas transparent films with dielectric dispersion are formed at pressures above 2.81 × 10-3 Pa. According to the data of quantumchemical simulation, the absorption peak at a photon energy of 4.6 eV in TaOx observed in the absorptioncoefficient dispersion spectrum is due to oxygen vacancy. The peak in the Raman-scattering spectra of TaOx films with metallic dispersion at frequencies of 200-230 cm-1 is presumably related to tantalum nanoclusters. [ABSTRACT FROM AUTHOR]

Somatic mutations of KRAS, PIK3CA, and BRAF cause insensitivity of colorectal tumors to therapy with anti-EGFR monoclonal antibodies, necessitating a genetic testing prior to therapy. A biological microchip was developed and validated to allow detection of 19 somatic mutations in KRAS, PIK3CA, and BRAF genes. The method combines LNA-clamp PCR and allele-specific hybridization on a microchip and detects mutant DNA in 100 times wild-type background (1%). A total of 66 DNA samples isolated from colorectal tumors were tested with the biochip. Possible associations between the genetic status of the tumor and the patient's characteristics (age, sex, tumor localization, stage, and TMN) were assessed statistically. KRAS mutations were more common in females ( P = 0.02) and in patients with distant metastasis ( P = 0.04). Other associations between the presence of mutations and patient characteristics were not observed. The method proved highly sensitive and can be used in oncology to select patients who sensitive to therapy with antiEGFR monoclonal antibodies. [ABSTRACT FROM AUTHOR]

Cathodo- and photoluminescence of amorphous nonstoichiometric films of hafnium oxide are studied with the aim to verify the hypothesis that oxygen vacancies are responsible for the luminescence. To produce oxygen vacancies, hafnium oxide was enriched in surplus metal during synthesis. To reduce the oxygen concentration, the film was annealed in oxygen. A qualitative control of the oxygen concentration was carried out by the refractive index. In the initial, almost stoichiometric films we observed a 2.7-eV band in cathodoluminescence. Annealing in oxygen results in a considerable increase in its intensity, as well as in the appearance of new bands at 1.87, 2.14, 3.40, and 3.6 eV. The observed emission bands are supposed to be due to single oxygen vacancies and polyvacancies in hafnium oxide. The luminescence increase under annealing in an oxygen atmosphere may be a result of the emission quenching effect. [ABSTRACT FROM AUTHOR]

Crystallographic parameters of TlInSSe solid solutions have been measured by X-ray diffraction. Dependences of the unit-cell parameters on the composition are determined. It is established that the values of parameters a, b, and c and the angle β decrease with an increase in x. It is shown that the TlInSSe system includes a continuous series of solid solutions based on the TlInSe compound with tetragonal symmetry at x values ≤ 0.4, while at x ≥ 0.6 solid solutions based on the TlInS compound with a monoclinic structure are formed. [ABSTRACT FROM AUTHOR]

Colorectal cancer is one of the most common cancers in the world. Changes in AKR1B1 and AKR1B10 expression levels, whose diagnostic value was previously shown for several other cancer types, were studied in colorectal tumors. These genes encode aldose reductases, members of the aldo-keto reductase superfamily, which comprises enzymes capable to reduce a range of aromatic and aliphatic aldehydes and ketones. They are also involved in retinoid metabolism and carcinogenesis. AKR1B1 and AKR1B10 mRNA levels were compared in paired specimens of normal and colorectal tumor tissues using RT-PCR and quantitative real-time PCR. For the first time, the downregulation of these genes was demonstrated in colorectal carcinoma. AKR1B10 expression was decreased in most tumor specimens (88%, 65/74) even at the early stages, and in more than 60% of cases mRNA levels were decreased more than 10-fold. AKR1B1 mRNA levels were decreased in 10% of specimens. Therefore, these two structurally similar genes show quite different mRNA expression patterns in colorectal cancer, suggestive of their different functional roles in the intestine. Significant downregulation of AKR1B10 expression can be considered a potential diagnostic marker of colorectal cancer. [ABSTRACT FROM AUTHOR]

Optical characteristics of the HfO2 − xN x and TiO2 − xN x films obtained by reactive ion beam sputtering have been investigated by spectral ellipsometry. The chemical composition of the films was determined using X-ray photoelectron spectroscopy. The nitrogen content in the oxynitride films (determined by the N2/O2 ratio in the gas mixture during synthesis) reached ≈9 at % for TiO2 − xN x and ≈ 6 at % for HfO2 − xN x. It is found that the dispersion relations n(λ) and k(λ) for the TiO2 − xN x films change from those characteristic of titanium dioxide to those typical of titanium nitride with an increase in the nitrogen content from 0 to ≈9 at %. The optical parameters of the HfO2 − xN x films depend weakly on the nitrogen content in the range 0–6 at %. [ABSTRACT FROM AUTHOR]

The optical properties, interface structure, and thermal stability of the ZrO2 films grown on Si(100) were investigated in detail. A 2 nm thick interfacial layer (IL) is formed at the ZrO2–Si interface for the as-grown ZrO2. The optical constants of ZrO2 films and IL correspond to amorphous-ZrO2 and amorphous-SiO2, respectively. The oxidation and IL growth at 900 °C, as a function of annealing time, exhibit a two-step behavior with a slow and a fast growth-rate zones. The transition from a zone of slow to fast rate is attributed to structurally modified ZrO2 facilitating the faster oxygen transport to the ZrO2/Si interface. [ABSTRACT FROM AUTHOR]