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Magnetic nanoparticles are widely used in biomedicine for MRI imaging and anemia treatment. The aging of these nanomaterials in vivo may lead to gradual diminishing of their contrast properties and inducing toxicity. Here we describe observation of the full lifecycle of 50-nm magnetic particles from their injection to the complete degradation in vivo and associated impact on the organism. We found that in 2 hours nanoparticles were eliminated from the bloodstream, but their initial biodistribution changed over time. In 1 week major part of nanoparticles was transferred to the liver and spleen, where they degraded with a half-life of 21 days. MRI and magnetic spectral approach revealed preservation of contrast in these organs for more than 1 month. Particle degradation led to increased number of red blood cells and blood hemoglobin level due to released iron without causing any toxicity in tissues. Also, we observed an increase in gene expression level of Fe-associated proteins such as transferrin, DMT1 and ferroportin in the liver in response to iron particle degradation. A deeper understanding of the organism response to the particle degradation can bring new directions to the field of MRI contrast agent design.

The paper presents the results of comparative studies on the modifying ability of La, Sc (REM group), and Sr (AEM group) in the processing of a GK-AlSi10Mgwa alloy (Al–Si–Mg system). The elements were introduced into the melt in the form of AlLa12, AlSc2, and AlSr10 master alloys in the same amount (0.25 wt.%). The effects of the added elements on the microstructure, mechanical properties, and electrical conductivity in the cast state were evaluated. Structural homogeneity was evaluated along the height of the plate samples according to recorded electrical conductivity values. Varying degrees of modification were used to enhance the mechanical properties and electrical conductivity of the GK-AlSi10Mgwa alloy. While, upon modification with Sr additives, the maximum increase in ultimate strength (by 60–66%) was noted, the HB hardness and the relative elongation of the alloy increased to a lesser extent in comparison with modification by La and Sc. Modifiers of the REM group (La and Sc) altered the morphology of the main phases in different ways. In La-modified samples, the morphology of eutectic silicon crystals was changed from lamellar to fibrous. Modification by Sc additives caused similar changes in the morphology of eutectic silicon with partial modification of α-Al dendrites. In terms of modifying α-Al dendrites and eutectic silicon crystals, strontium – an alkaline-earth metal – had the greatest effect. Such modification leads to changes in the alloy structure, eventually resulting in increased electrical conductivity. Although the maximum increase in electrical conductivity was brought about by Sr-modification of the alloy samples, the fact that this change is not significant indicates an increase in the homogeneity of the microstructure.

Event-related rhythmic brain activity underlying responses to sound stimulus movement (the motion onset response, MOR) was studied. EEG recordings were made in conditions of either active or passive localization of moving stimuli by healthy subjects. The influences of the directedness of the listener’s attention and the speed of the stimulus on the overall response (MOR) and on event-related spectral perturbation (ERSP) and phase coherence (inter-trial phase coherence, ITC) were studied. Passive localization of moving stimuli evoked phase reorganization of activity in the δ–α range. The maximum movement speed induced weakly coherent oscillations. Attraction of attention to sound movement was more strongly reflected in rhythmic activity than in the overall reaction. Active localization was accompanied by phase rearrangement and increases in δ–θ oscillations after movement onset and the appearance of oscillations which were not phase-synchronized with movement stimulus onset.

A new approach to direct quantitative detection of small molecules (haptens) by dynamic light scattering biosensing is presented. The proposed technique implements a homogeneous competitive immunoassay and is based on optical detection of specific inhibition of nanoparticle aggregation induced by the analyte in a sample. The technique performance was tested both in buffer and milk for detection of chloramphenicol - antibiotic relevant to food safety diagnostics. Good specificity, sensitivity (LOD in milk is 2.4 ng/ml), precision (4.0 ± 1.2%), ruggedness (8.3%), and 96% recovery in conjunction with a record wide dynamic range (3 orders of magnitude) of the nanosensing technique were demonstrated. Such characteristics complemented by the assay simplicity (no washing step) and a short assay time make the approach attractive for application as an analytical platform for point-of-care and field-oriented diagnostics. Graphical abstract.

The contributions from the martensitic laths, dislocations, secondary phase particles, and supersaturated solid solutions to the overall strength of the 12%Cr–3%Co–2.5%W creep-resistant steel with low N and high B contents were calculated after various heat treatments consisting of normalizing followed by medium-temperature tempering. An increase in the normalizing temperature from 1050 to 1150 °C led to an increase in the average size of the prior austenitic grains from 44 to 68 μm, but the δ-ferrite fraction did not significantly change. Medium-temperature tempering in the range of 750–800 °C ensured the formation of a tempered martensite lath structure with an average martensitic lath/subgrain size of 0.23–0.34 μm, along with a high dislocation density inside the laths/subgrains, fine secondary phase particles such as M23C6 carbides along the boundaries of the prior austenite grains, packets, blocks, and martensitic laths/subgrains, and (Ta,Nb)X carbonitrides uniformly distributed inside the matrix. After medium-temperature tempering in the range of 750–800 °C, the ferritic matrix was supersaturated with substitutional elements such as Cr, W, Mo, and Cu. An increase in the tempering temperature from 750 to 800 °C led to decreases in the yield strength and ultimate tensile strength by 16.2% and 10.5%, respectively, as well as an increase in the elongation of 43.8%. The main contributions to the overall strengthening of the steel investigated after the different heat treatment regimens produced solid solution strengthening and precipitation hardening, which were independent of the tempering temperature, as well as lath boundary and dislocation strengthening, which was strongly dependent on the tempering temperature. Different approaches for evaluating the strengthening mechanisms and their contributions to the yield strength were applied, and the results are discussed.

The activity of foam ceramic and foam glass in terms of the silicate-alkali interaction in concrete was investigated. It was found that in the wet environment in concrete the vitrified walls of the pores of the aggregates are chemically active. The transformations of foam ceramic include gelation of the pore walls with formation of an alkaline aluminosilicate gel followed by its crystallization. This binds the active components on such an aggregate in the crystalline phases, which are inert in a moist environment. The final stage of the transformation of the foam glass is noncrystallizing, alkaline, hydrated, silica gel.

The studies reported here addressed analysis of the N1 and P2 components and mismatch negativity (MMN) on discrimination of signals with dynamic changes in intensity in different acoustic contexts. Changes in context in the conditions of the oddball paradigm were created on the basis that each stimulus operated both as a standard and as a deviant in different series, such that the physical differences between signals remained unaltered and their functional relationship flipped to the opposite. Three types of sound signal were used: stimuli with constant intensity and two amplitude-modulated stimuli (linear and stepwise, each with an increase or decrease in intensity). Increases and decreases in the intensity of deviant stimuli induced MMN in the late latency period (>250 msec) without overlap with the N1 component. The difference in signals with linear and stepwise amplitude modulation indexed by mismatch negativity was determined by the direction of deviation in the structure of the sound series. Increment MMN anticipated decrement MMN by 90–100 msec regardless of the type of modulation. Amplitude differences were seen in responses to deviants with stepwise modulation in the context of consistent standards: increment MMN was greater than decrement MMN. The acoustic context affected only increment MMN. These results are consistent with views of the asymmetry in the perception of increasing and decreasing sound intensity, associated with their different biological significance.

The corrosive effect of alkali in the cement (ASR interaction) on porous aggregates — foam ceramic and geofoamsitals (analogs of foam glass and foam sitals) in an alkaline medium modeling the liquid phase of setting cement was investigated. It was found that the devitrification of glass melt in the process of thermoactivated pore formation increases the ASR-tolerance of foam ceramic aggregates provided that the crystals are uniformly distributed over the wall thickness of the pores. It is shown that in an alkaline medium the active surface of foam ceramic aggregates is encapsulated by crystalline Ca-, Na-aluminosilicates and subsequent ASR interaction ceases.

A simple model is designed for an inductive immunosensor in which the magnetic particles are attached to the bioreceptors to form a sandwich on the surface of an inductor. The inductor consists of a coil covered on a silicon oxide wafer. The coil comprises 250 turns of a planar gold wire, which is approximately 200 nm thick and 392 mm long, placed in a circle with a diameter of 2 mm. The model is well characterised by controlling the geometrical and electrical parameters and also the permeability of the magnetic material. To evaluate the feasibility of the model for virus monitoring, a novel inductive immunosensor is designed and for the first time applied for the detection of hepatitis B surface antigen (HBsAg). At first, Fab′ segment of primary anti-HBsAg is immobilised on the coil. Then, the coil is exposed to HBsAg and the complex is introduced to a secondary antibody conjugated with magnetic particles to form an immune-sandwich. Finally, the influence of magnetic particles on the coil inductance is recorded and used as a signal for HBsAg detection. The magnetic inductive immunosensor showed specific responses toward HBsAg with the detection limit of 1 ng mL−1, linear range of 1 to 200 ng mL−1, and a sensitivity of 6 × 10−4 mL ng−1. The experimental results showed a very good agreement with simulation data indicating the compatibility of sensor sensitivity to the expected theoretical values.

The effects of loading frequency on the fatigue behavior of non-deep-rolled (NDR) and deep-rolled (DR) austenitic stainless steel AISI 304 were systematically clarified at elevated temperatures, especially at temperatures exhibiting the dynamic strain aging (DSA) phenomena. Tension-compression fatigue tests were performed isothermally at temperatures of 573 K and 773 K (300 °C and 500 °C) with different loading frequencies of 5, 0.5, 0.05, and 0.005 Hz. For the DR condition, the residual stresses and work-hardening states will be presented. It was found that DSA would be detected at appropriate temperatures and deformation rates. The cyclic deformation curves and the fatigue lives of the investigated austenitic stainless steel AISI 304 are considerably affected by the DSA, especially on the DR condition having high dislocation densities at the surface and in near-surface regions. In the temperature range of the DSA, residual stresses and work-hardening states of the DR condition seem to be stabilized. The microstructural alterations were investigated by transmission electron microscopy (TEM). At an appropriate temperature with low loading frequency, the plastic deformation mechanism shifted from a wavy slip manner to a planar slip manner in the DSA regimes, whereas the dislocation movements were obstructed.

The relationship between auditory event-related potentials (the N1, P2, cN1, and cP2 components) and the rate of motion of a sound stimulus was studied in humans in passive conditions (attention distracted from the stimulation) and during active localization of the beginning and end of the trajectory. Sound signals were presented dichotically and consisted of two fragments. Stimuli were initially stationary and located at the center of the head, after which they moved from the center of the head towards the right or left ear. Motion was created using a linear increase in the interaural time delay. As compared with passive listening, responses signal onset during active listening generated a greater-amplitude N1 component, while the P2 component had both greater amplitude and longer latency. In response to motion onset, the N1 and P2 components had greater amplitudes and latencies in active conditions. Monotonic relationships between N1 and P2 amplitude and latency on the one hand and stimulus movement speed on the other, were seen in both active and passive conditions. Contralateral asymmetry of responses to stimulus motion onset was seen only in the left hemisphere.

The aim of the present work was to compare EEG spectral characteristics as subjects discriminated stationary and moving sound stimuli in active (paying attention to the stimulus) and passive (not paying attention) listening using an oddball paradigm. The standard signal was a sound signal modeling the action of a stationary sound source located at the midline of the head. Deviant stimuli consisted of two types of moving stimulus with smooth and stepwise movements. Signifi cant changes in EEG spectral power were found in the range 3–30 Hz. The effects of deviant stimulus movement dynamics on the power of θ oscillations (3–7 Hz) were more marked in conditions of active discrimination: the increase in power was greater for stepwise movement of deviant stimuli than for smooth movement and also on movement of the stimulus to the right. Suppression of α rhythms (8–11 Hz) was seen in the active listening task, this being most marked on smooth movement of deviant stimuli. An increase in power in the lower subrange of the β rhythms (12–15 Hz) was greater for stepwise movement than smooth movement of deviants. Interhemisphere asymmetry in the extent of suppression of power in active conditions as compared with passive was seen throughout the β range. Suppression was greater in the right hemisphere than at the midline of the head or in the left hemisphere. Interhemisphere asymmetry of β rhythms was independent of the spatial properties of the stimuli. The presence of hemisphere asymmetry may be associated with paying attention to the task performed and the formation of the motor response. Overall, for all frequency ranges studied, the dynamics of stimulus movement had greater infl uences on EEG spectral power in conditions of active discrimination than in passive conditions.

Results are given for a study of the effect of hot rolling parameters on the mechanical properties of heat-treated cold-rolled product of two-phase ferritic-martensitic steel (TFMS) of grade HCT980X (EN10336:2007). Temperatures for the end of rolling and coiling are varied during hot rolling of a metal laboratory melt. Hot-rolled product obtained by different versions is heat treated by regimes modeling annealing in a continuous hot galvanizing unit (CHGU). Morphological features of structural components and excess phase precipitates in different treatment stages are studied. The effect of strip tension in a CGHU on a set of mechanical properties with a change in temperature is analyzed. Mechanical test results are used to determine the optimum heat treatment temperature range providing the required level of cold-rolled steel strength properties.

The aim of the present work was to assess interhemisphere asymmetry of the N1, P2, and N250 components of auditory event-related potentials (ERP) and mismatch negativity (MMN) in passive discrimination between moving sound stimuli in an oddball paradigm. Stimulus movement was created using a linear increase in the interaural time delay ΔT in dichotically presented signals. The amplitudes of the N1 and P2 components were greater in the right hemisphere, this being particularly clear in the frontolateral area. The amplitude of the N250 component in the frontolateral and frontomedial areas was greater in the hemisphere contralateral to the sound stimulus. The direction of movement of sound stimuli had no effect on the asymmetry of ERP and MMN components. The right-hemisphere asymmetry of N1 increased with increases in stimulus speed, while asymmetry of P2 was maximal for short movement trajectories. Asymmetry of N250 and MMN was identified in terms of differences between standards and deviants, i.e., a higher-order feature. Thus, these studies demonstrated differences in the nature of interhemisphere asymmetry for the early and late ERP components, reflecting differences in the neural structures supporting primary analysis of the stimulus and higher cognitive processes.

The possibility of shortening the heat treatment hold of silumins of the Al – Si – Cu system by changing the parameters of the structure under chill casting is considered and a criterion for their evaluation is suggested. Alloys AK6M2 and AK8M3ch are used to demonstrate experimentally that decrease in the sizes of the crystals of primary silicon and in the transverse size of the α-Al secondary dendrite arms can halve the time of holding for quenching and aging at a guaranteed margin of the strength properties.

The effect of charge billet structure and form of fluxes on structure, density, and gas content of alloy AK6M2 (Al – Si – Cu system) is studied. Alloys prepared from finely crystalline charge billet have smaller phase component sizes, lower gas content, and increased solid state density, and use of coarsely crystalline charge billets for alloy preparation necessitates an increase in flux preparation consumption in the stage of alloy preparation for casting.

Nanoparticles with biocomputing capabilities could potentially be used to create sophisticated robotic devices with a variety of biomedical applications, including intelligent sensors and theranostic agents. DNA/RNA-based computing techniques have already been developed that can offer a complete set of Boolean logic functions and have been used, for example, to analyse cells and deliver molecular payloads. However, the computing potential of particle-based systems remains relatively unexplored. Here, we show that almost any type of nanoparticle or microparticle can be transformed into autonomous biocomputing structures that are capable of implementing a functionally complete set of Boolean logic gates (YES, NOT, AND and OR) and binding to a target as result of a computation. The logic-gating functionality is incorporated into self-assembled particle/biomolecule interfaces (demonstrated here with proteins) and the logic gating is achieved through input-induced disassembly of the structures. To illustrate the capabilities of the approach, we show that the structures can be used for logic-gated cell targeting and advanced immunoassays.

Data are presented on the level of contamination of a site in a surveyed part of Kiev Oblast on the fourth day after an accident in which radionuclides were discharged from a damaged reactor. It is shown that the contamination on the observation date was much weaker than after discharges were completed by mid-May 1986. The fraction factors of the radionuclides during discharge from the damaged reactor and atmospheric transport to the point of observation of the site contamination are calculated.

Fe3O4 nanoparticles were coated with a layer of citric acid, forming coordination bonds between citrate ions and iron ions. The resulting aqueous citrate ferrite colloid was used as a T2-weighted MRI negative contrasting agent. Sequential i.v. doses of citrate ferrite and Magnevist led to increases in MRI image contrast for 40 h and brightness for 30 min; scanning using a Bruker Biospec BC 70/30 USR biospectrotomograph yielded enhanced MRI images. This enhancement of MRI images was used to monitor oncogenesis during magnetohydrodynamic thermochemotherapy (MT) of mammary adenocarcinoma Ca 755 in female C57Bl/6j mice. Dextran ferrite colloid containing cyclophosphamide was tested as a magnetically directed antitumor agent using MT. Treatment of non-infiltrating tumors of volume ≈ 30 mm3 with six sessions of MT each lasting 30 min at 46°C led to 40% tumor regression and 300% increases in survival time. Treatment of infiltrating tumors of volume ≈ 300 mm3 in the same conditions yielded a 200% increase in survival time.

The results of testing corrosion resistance longevity in coatings of the Ni-M-Cr-Al-Y system at temperatures of 800, 850, and 900°C are given. The kinetic dependences of corrosion are determined, successive stages of the degradation of coatings are identified, and the effect of alloying coatings with chromium and aluminum on their degradation and durability is established.

The effect of the parameters of mechanical activation on the morphology and particle size of a mechanically activated charge of the Mo-Cu system is studied. The influence of the composition (the copper content) and of the temperature of preparation on the density, microstructure, and hardness of the developed pseudoalloy is studied.

The perturbed angular correlation (PAC) measurements with the 111In-111Cd nuclear probe embedded into the lattice of the cubic (C15) Laves compound ZrZn2 showed that 111Cd nuclei experienced an axially symmetric electric quadrupole interaction with a frequency νQ = 132.4 MHz at room temperature. The samples were synthesized and doped with the probe at a pressure 8 GPa. The temperature dependence of νQ was shown to be linear: νQ(T) = 147(1 − 0.033 T) MHz. Since the value of νQ is very close to that known for 111Cd in the lattice of Zn, we have checked if it could be assigned to residual Zn metal in the sample. For the Zn sample melted and doped with 111In at 8 GPa we have obtained νQ = 117.3 MHz at 300 K and 127 MHz at 80 K – both values considerably lower than that for 111In doped Zn samples prepared at an ambient pressure. These data, and the fact that νQ(T) in Zn is known to follow the T3/2 law, allow to attribute the νQ value quoted above to 111Cd nuclei at the substitutional sites with tetrahedral symmetry in the Zn sublattice of ZrZn2.

Electron paramagnetic resonance (EPR) of Ho3+ single ions and Ho3+−Mg2+-vacancy-Ho3+ associates in holmium-doped forsterite single crystals are studied at 9.4, 37.3 and 65–250 GHz. Crystals were grown from melt by the Czochralski technique in slightly oxidizing atmosphere. For both centers, directions of the principal magnetic axes and parameters of the effective spin Hamiltonians describing dependences of electron-nuclear levels on applied magnetic field are obtained. For Ho3+ substituting Mg2+ in the M2 site as the single ion and for Ho3+ ions in dimer centers, values of crystal field parameters related to a real crystal lattice structure are estimated in the framework of the exchange charge model. The calculated crystal field energies, values of theg-factors of the ground Ho3+ quasi-doublet and the directions of the corresponding magnetic moments agree satisfactorily with the data obtained from measurements of EPR and optical absorption and site-selective luminescence spectra.

The interactions in the systems H2O-Am-SO2 (Am is formamide, dimethylformamide, acetamide, urea, tetramethylurea, tert-butylurea) at 278 and 293 K were studied pH-metrically. The results suggest formation of intermolecular and ion-molecule associates. The composition and stability of the compounds formed strongly depend on the structure and concentration of the solution components and on temperature.

We have constructed a very large virtual diversity space containing more than 10(13) chemical compounds. The diversity space is built from about 400 combinatorial libraries, which have been expanded by choosing sizeable collections of suitable R-groups that can be attached to each link point of their scaffolds. These R-group collections have been created by selecting reagents that have drug-like properties from catalogs of available chemicals. As members of known combinatorial libraries, the compounds in the diversity space are in general synthetically accessible and useful as potential drug leads. Hence, the diversity space can be used as a vast source of compounds by a de novo drug design program. For example, we have used such a program to generate inhibitors of HIV integrase enzyme that exhibited activity in the micromolar range.

Representatives of five genera of psychroactive oligotrophic bacteria, Arcocella, Renobacter, Spirosoma, Caulobacter, and Methylobacterium, were for the first time shown to be capable of growing at a negative temperature (−2°C). Long-term cultivation (for 116 days) at a low temperature under limitation by the carbon source is stressful for oligotrophic bacteria and leads to the death of a part of the cell population. The number of viable cells of Caulobacter crescentus decreased by two to three orders of magnitude. Over the studied period of time, Renobacter vacuolatum cells retained viability at a low temperature, whereas, at room temperature, the titer of colony-forming cells decreased by two orders of magnitude under starvation stress.

The auditory system in humans and animals makes virtually no discrimination of phase changes in the structure of monaurally presented sound signals. However, electrophysiological studies have demonstrated marked changes in the responses of the central parts of the auditory system when the phase structure of the signal changes during presentation of the same type of stimulation. We have suggested that this inconsistency is due to the preparative role of phase effects during monaural stimulation for subsequent operations in the auditory system involved in determining the location of a sound source in space. This report presents experimental data on defined changes (increases in amplitude) in the electrical responses of the midbrain center of the auditory system (inferior colliculus) in antiphase binaural presentation of series of sound impulses (comparison with synphase presentation). These changes may be part of the mechanism underlying the interference resistance of the auditory system during determination of the location of a sound source (binaural release from masking). Neuronal cortical activity is sensitive and selective to dynamic interaural changes in the phase spectrum of the signal, which may provide the basis of the mechanism for locating a moving sound source. Auditory evoked potentials in humans demonstrate memorizing of the direction of movement of a sound image, as shown by the changes in parameters on presentation of stimuli of different locations (deviant stimuli) differing from the standard parameters of mismatch negativity.

Electronic absorption spectroscopy and potentiometry were applied to study complexation at 293 K in a system constituted by water, carbamide, and sulfur dioxide. The composition and stability of the molecular and ionic complexes formed was determined in relation to the concentration of components in solution.

Criteria for developing the ball lightning theory based on the results of observations are analyzed. It is assumed that the key features of ball lightning are a large energy (more than 106 J) and long lifetime (more than 1 s). We exclude from consideration theories which do not explain these features and concentrate our attention on the analysis of three models where the large energy of the autonomous ball lightning and the forces providing the compression of the ball lightning substance are taken into account. The first considered model was developed by Geert Dijkhuis, in which the appearance of a force directed towards the system center is attributed to the Bose condensation of vortices of degenerated electrons as well as to gradient forces arising due to a nonuniform distribution of the electron density over the ball lightning volume. The second model proposed by Vladimir Bychkov assumed that the energy reservoir of ball lightning is polymer threads carrying a big electric charge. Our model assumes that the energy is stored in the form of kinetic energy of ions which the positively charged core of ball lightning is thought to consist of. The core is compressed by a dielectric shell which, in turn, is shrunk by the force created due to the nonuniform electric field of the core. The merits and limitations of these and other models are discussed.

Differential sensitivity to the velocity of a sound source image in the vertical plane was studied by using two signals with different spectral bandwidths: 0.25–4 kHz (signal 1) and 4–12.5 kHz (signal 2). Five subjects were tested. Sequential switching of loudspeakers with similar frequency characteristics simulated movement of a sound source. Differential velocity thresholds were determined for two reference velocities: 58 and 115°/s. Significant differences in the absolute values of these thresholds were found for signals with different spectral compositions. The threshold for signal 1 (0.25–4.0 kHz) exceeded that for signal 2 (4.0–12.5 kHz) twofold at 58°/s and 1.6-fold at 115°/s.

A mechanism of SO2 chemisorption by aqueous solutions of carbamide was suggested. The effective rate constants of accumulation of hydrogen ions in the reaction of sulfur dioxide with aqueous solutions of carbamide in the range 278-313 K were determined.

The CdTe/Cd1−xMn x Te quantum well structures have been grown by pulsed laser deposition. X-ray diffraction analysis demonstrates high structural quality of the deposited layers and nanostructures. In the magnetoabsorption spectra the large Zeeman splitting of exciton peak which is corresponded to the heavy-hole exciton transition in the CdTe quantum well layers is revealed. The Faraday rotation spectra of the superlattices is interpreted in framework of the exciton transition for the Cd1−xMn x Te layers at a higher photon energy. Influence of different factors on behavior of the Zeeman splitting and the Faraday rotation in the studied nanostructures is discussed.

Evoked potentials in the inferior colliculus and auditory areas of the cortex were studied in anesthetized guinea pigs and long-latency auditory evoked potentials (LAEP) were studied in waking humans using sequential binaural presentation of pairs of clicks – the masker and the masked signal – with a variable interval between them, to provide the conditions needed for the psychophysical phenomenon of direct forward masking. Introduction of phase differences between the masker and the masked signal led to decreases in suppression of responses to the masked signal and to faster recovery of the reaction types recorded. The greatest relative differences between response magnitudes to antiphase and synphase masked signals were seen at the beginning of the recovery process, and were 1.6, 1.5, and 1.4 respectively for responses from the inferior colliculus, auditory area of the cortex, and LAEP at stimulus intensities of 50–65 dB sound pressure level, differences subsequently decreasing to zero. There was a positive correlation between this measure and the stimulus intensity. The greatest differences between the time at which the recovery process ended for responses to antiphase and synphase masked signals were 4, 250, and about 2000 msec respectively for the inferior colliculus, auditory area of the cortex, and LAEP.

The discrimination of the angular velocity of ventrodorsal and dorsoventral movement of an acoustic image was studied in nine test subjects. The experiments were performed using an apparent movement produced by consecutive activation of loudspeakers located along an arc in the vertical plane. The differential thresholds were measured by the minimum increment method. As the velocity of an acoustic image movement in opposite directions increased, the values of its mean absolute differential thresholds increased monotonically. Regression lines plotted by linear approximation of these values did not differ significantly.

Polluted air and the derived photochemical smog are the sources of free radicals in the atmosphere. Organic peroxides present in the smog mediate formation of peroxide radical. Oxygen species are formed by purely physical mechanisms, for instance, energy consumption converts molecular oxygen to an excited singlet state. Six active oxygen species are known: ozone, atomic oxygen, perhydroxyl, superoxide, and singlet oxygen. Singlet oxygen is the most harmful oxygen product for living cells, while hydrogen peroxide is the least harmful. Molecular oxygen is hardly toxic for prokaryotes due to an efficient protection of microbial cells by specific enzymes. This work experimentally confirms the harmlessness of molecular oxygen.

For determination of the stability of In3+ complexes with diethylenetriaminepentaacetic acid (DTPA) and newly synthesized chelates-derivatives of 4-amino-2-hydroxybutyric acid in aqueous solutions of pH 1.0–7.5, at room temperature, the time differential perturbed angular γ−γ correlation method was used. Data obtained show that only one of the new ligands forms as strong a complex as DTPA and can be used in water at pH∼7.

A new procedure is suggested for determining the grain size composition of polydispersed powders with a microscope. It is based on dividing the whole size range into four parts. The number of grains in the field of view is determined for each part separately at a magnification level corresponding to each part. The method developed assumes that samples are homogeneous.

The reactivity of cyclohexanediones and their monoethylene ketals with hydrogen peroxide was studied. It was established that 1,2- and 1,3-cyclohexanediones virtually do not react with H2O2, whereas 1,4-cyclohexanedione forms 1,4-dihydroxy-1,4-dihydroperoxycyclohexane. Monoethylene ketals of cyclohexanediones react with hydrogen peroxide to form the corresponding α-hydroxy-α-hydroperoxides. The stereoelectronic factors determining the difference in reactivity of the carbonyl fragment in cyclohexanone, 1,2-cyclohexanedione, and its monoethylene ketal were analyzed within the framework of the semiempirical quantum chemical method MNDO.

Low-lying energy states of the [Fe3S4]0 cluster have been calculated by taking into account the double exchange, superexchange and vibronic interaction. It was found that the adiabatic potential of the excited state withS=0 corresponds to the full delocalization of the “excess” charge. From the analysis of experimental data of Mossbauer spectroscopy and the temperature dependence of the magnetic susceptibility the double exchange parametert≥4000 cm−1 and the vibronic interaction parameter λ2/2k cm−1 have been estimated.

In anaesthesized guinea pigs the evoked potentials of the auditory cortex were studied in a forward masking paradigm. In-phase and out-of-phase binaurally presented clicks with interaural time delay (ITD) were used as masker, in-phase click with ITD = 0 served as probe signal. Addition of the masking stimulus suppressed the probe-evoked response that followed the masker. The magnitude of the suppression correlated with the amount of the masker-evoked response: an increase in masker-evoked excitation caused a greater reduction in probe response magnitude. Amplitude of masker-evoked response was seen to be a monotonic or non-monotonic function of ITD. The non-monotonic response exhibited a sensitivity to the interaural phase differences when in-phase and out-of-phase maskers were presented, and showed the tendency to be periodic function of ITD in the expanded range of ITD values. Phase-sensitive responses differed in recovery time following the in-phase and out-of-phase masking stimuli. At near-threshold levels of a forward masker an enhancement of the probe-evoked response was observed.

For purposes of establishing the characteristics of the transport and determining the limits of propagation of radioactive pollutants created by the nuclear power industry, in the western Arctic Seas, the Barents, Kara, and Greenland Seas were inspected in August-October of 1982 during the 12th voyage of the research vessel Otto Schmidt. The basic results are presented in this paper.

mode. It is typical of this mode that at each instant information exchange takes place pray between two ne~%vork nodes. These nodes can be commutated with each other only for a relatively short time since another pair must exchange information in the next time interval. ~'hile reducing the effectiveness of information exchange between two nodes in genera[, the time sharing mode makes it possible to use in the network communication channels which are more economical (have lower transmission capacity) than in the mode in which any node can exchange information with any other mode at any instant to which corresponds the multiproduct network mode[. Here we consider the synthesis of an optima[ single-product network and certain algorithms are proposed for the design of suboptimal networks. Problem Formulation. Assume that the desired network has N nodes A i and that there are given N(N- i)/ 2 numbers Rij which represent the demands on the magnitude of flows between A i and Aj (i = I, N; j = I, N). We have to find the network topology and transmission capacities Bij of the communication channels (i, j) such that flows can be transmitted between the nodes A i and Aj, and that the total transmission capacity of the channels is minimal

A la rge number of pape r s have been devoted to the effect of the a sh deposi ts f o rmed during the combust ion of a fuel on the co r ros ion of the s t ruc tu ra l m a t e r i a l s of gas turbines . Usual ly the purpose of an invest igat ion is to find out the spec ia l fea tures , study the mechan i sm, or evaluate the co r ros ion r e s i s t ance of m a t e r i a l s in ash deposi ts , the c o r r o s i v e n e s s of which is de te rmined by the p r e sence in them of vanadium compounds. The effect on the c o r r o s i o n of the m a t e r i a l s of sodium sulfate, one of the chief const i tuents of the a sh f r o m a number of fuels , has been examined cons iderab ly less . F u r t h e r m o r e , up to the presen t , the ef fec t of a c o r r o s i v e a tmosphe re on the m a t e r i a l has been analyzed p re f e r en t i a l l y without, as a rule, t e s t ing the effect of the s t r e s s e s . The p rob lem in the work now desc r ibed was to invest igate the effect of synthetic a sh containing sodium sulfate and sodium chloride on the s t r e s s r u p t u r e s t rength of a nickel alloy.