Violet-blue photoluminescent emission has been observed in aluminium oxide films deposited by the ultrasonic spray pyrolysis process at atmospheric pressure, using solutions of 0.05
M aluminium ...acetylacetonate in a mixture of two parts of deionised water and two parts of methanol and aluminium chloride in the same solvent mixture. The films were deposited at substrate temperatures in the range from 240 to 440°C. The refractive index has values lower than those associated with crystalline phases of Al
2O
3. These values are due to the amorphous nature of the deposited films and the incorporation of organic or chlorine related radicals. The photoluminescence excitation spectra show two peaks located at 281 and 371
nm, the latter being with higher intensity. The photoluminescent emission spectra are constituted by a broad band with a peak located at 405
nm and, it has a maximum intensity for the sample prepared at 380°C. It is suggested that this emission is associated with radiative recombination from an excited level of the aluminum ions. The photoluminescence emission spectra can be formed by several contributors, for all the samples, which suggests that these emissions are associated with aluminium ions incorporated in excess in aluminium oxide host on different sites, as it has been observed in several glasses. From an Arrhenius plot of the intensity of the peak located around 405
nm, as a function of substrate temperature an activation energy of 1.16
eV has been calculated.
Background.
In the majority of cases, contemporary pharmacological correction mainly focuses on the most effective analgesia. Therefore, the search for and research into new analgesic drugs are a ...priority in modern pharmacology.
Objective
— to establish the level of analgesic activity in eight novel heterocyclic compounds of 1,4-dihydropyridine derivatives synthesized in a classic test of orofacial trigeminal pain in animal experiments.
Methods.
An experimental preclinical randomized trial of the analgesic activity in 1,4-dihydropyridine derivatives was carried out. The experiment was conducted on 100 white male outbred rats in the laboratory of the Fundamental and Clinical Pharmacology Department, St. Luke Lugansk State Medical University, Lugansk People’s Republic. Novel 1,4-dihydropyridine derivatives were preliminarily investigated in a virtual biological screening by means of Swiss Target Prediction tool (Swiss Institute of Bioinformatics, Switzerland). The laboratory animals were divided into a control group (rats were exposed to acute pain syndrome by injecting 0.1 ml of 5% formalin solution into the vibrissae area without pharmacological correction), a comparison group (rats which received metamizole sodium (OOO Farmstandard) at a dose of 7 mg/kg 1.5 hour prior to acute pain syndrome modeling in the vibrissae area), and eight experimental groups (1.5 hours before formalin administration, novel 1,4-dihydropyridine derivatives under study at a dose of 5 mg/ kg were intragastrically injected). 10, 15 and 20 minutes after simulating acute pain, the number of scratching movements of the forelegs around orofacial region per minute was counted. Statistical processing of the results involved methods of mathematical statistics for quantitative variability and was carried out using Statistica 12.5 (IBM, USA).
Results.
Animals treated with 1,4-dihydropyridine derivatives
d02-133
and d02-172 under the experimental conditions showed a significant (13–21 times) decrease in scratching movements frequency by the 10th minute of observation in comparison with the control group. By 15th minute, the analgesic activity of the cyanothioacetamide derivatives increased 14 and 11 times as compared to these indicators of the reference group. After 20 minutes, the analgesic activity of these compounds in terms of inhibiting nociceptive impulses, as compared to the control group, was also high, as the number of scratching movements in the vibrissae area in animals of these experimental groups was 8–9 times lower than in control group. The orofacial trigeminal pain test detected the most exhibited analgesic activity in novel cyanothioacetamide derivatives
d02-139
,
d02-133
, and
d02-172,
which appeared to be higher than that of metamizole sodium.
Conclusion.
It was found that novel original derivatives of 1,4-dihydropyridine showed a high degree of analgesic activity.
The study is concerned with the structural, optical, magnetic, and transport properties of Zn.sub.1-xCo.sub.xO (x = 0.05-0.45) films produced on Al.sub.2O.sub.3 (0001) substrates at a temperature of ...T.sub.s = 500°C by pulsed laser deposition with fast particle separation. The film thickness is d = 60-300 nm. It is found that the Zn.sub.1-xCo.sub.xO ternary alloy retains its wurtzite-type crystal structure up to x = 0.35, if the films are produced at low buffer-oxygen pressures (~10.sup.-6 Torr). It is established that, in these conditions, the electron concentration is higher than 10.sup.20cm.sup.-3 because of the high density of oxygen donor vacancies. In this case, the films start to exhibit ferromagnetism in the magnetization and the anomalous Hall effect at temperatures above 100 K. The sign of the anomalous Hall effect is found to be positive and opposite to the sign of the normal Hall effect, as occurs in Co metal layers. This is indicative of the cluster nature of ferromagnetism of the Zn.sub.1-xCo.sub.xO films. For thin Zn.sub.1-xCo.sub.xO layers (d = 60 nm, x = 0.2) in a transverse magnetic field, profound hysteresis of the magnetoresistance is observed, which is indicative of the out-of-plain easy axis of magnetization of the films. The magnetic anisotropy is attributed to the structuring of the layers (elongation of magnetic clusters along the growth axis of the films). The structuring can lead to noticeable strengthening of the layer ferromagnetism. DOI:10.1134/S1063782614040186
Abstract
In this work the problem formulation is stated, and a mathematical model is developed for calculating the electroelastic deformation of polydisperse two-phase unidirectional fibrous ...structures. The object of the research was a unidirectional transversely isotropic composite with a two-phase polydisperse structure - a piezo actuator cell and fragments of polydisperse fibrous structures. The constitutive relations at the composite macrolevel were obtained for longitudinal and transverse electromagnetic loading with allowance for the phase conductivity. The coefficients of the electromagnetic coupling of the composite were numerically determined depending on the volume fraction of the piezoelectric phase in the fibers and matrix form. The analysis of the obtained numerical solutions was carried out, the coincidence of the analytical solution with the solution of the asymptotic averaging method for an ideal periodic fibrous structure was obtained. Recommendations on the volumetric content of phases in a two-phase polydisperse composite are presented.
The results of a study of the short gamma-ray burst GRB 231115A in the X-ray and gamma-ray ranges are presented, based on data from the INTEGRAL and Fermi space observatories. The source of the burst ...is localized by the IBIS/ISGRI telescope of INTEGRAL observatory with an accuracy of \(\leq\) 1.5 arcmin, it is located in the Cigar Galaxy (M 82). Early follow-up observations of the burst localization region were carried out in the optical range with the 36-cm telescope of the ISON-Kitab observatory and the 70-cm telescope AS-32 of the Abastumani Astrophysical Observatory, the optical emission has not been detected. The proximity of the host galaxy (\(D_L \simeq 3.5\) Mpc) significantly limits energetics of the event (\(E_{iso}\ \sim\ 10^{45}\) erg) and allows us to interpret the burst as a giant flare of a previously unknown soft gamma repeater (SGR) which is an extreme manifestation of the activity of a highly magnetized neutron star (magnetar). This conclusion is confirmed by the energy spectrum atypically hard for cosmological gamma-ray bursts, as well as the absence of optical afterglow and gravitational wave signal, which should have been detected in the LIGO/Virgo/KAGRA experiments if the burst was caused by a merger of binary neutron stars. The location of the burst in the \(E_{p,i}\) -- \(E_{iso}\) and \(T_{90,i}\) -- \(EH\) diagrams also suggests that GRB 231115A was a magnetar giant flare. This is the first well-localized giant flare of an extragalactic SGR.
Abstract
In this article, a mathematical model was formulated that describes the dynamic behavior of MFC actuators. The model was developed on the basis of numerical-analytical methods for solving ...coupled boundary value problems of electromagnetoelasticity for inhomogeneous media equipped with piezoactive structural elements and loaded with coherent electromechanical disturbances. Within the framework of the performed numerical experiments, stationary harmonic axisymmetric oscillations of an elementary composite two-phase MFC actuator cell loaded with coherent electromechanical disturbances were considered. The calculation of the MFC actuators complex impedance and conductivity values, taking into account the energy losses and phase shift at different levels of the control electric voltage, was carried out.
The purpose of research is the assessment of the individual cancer risk (ICR) for workers of the basic occupations in key branches of industry of the Irkutsk region. There was executed the ...calculation of ICR levels for workers of the basic occupations of the aircraft industry, aluminum smelters and vinyl chloride production plants. The estimation of the exposure for workers was carried out according to long-term time-weighted average concentrations in the air of the working area, for the population - on annual average concentrations in the ambient air. To assess the risk that is not associated with the profession, the dose was calculated for the period of life (70 years). When calculating the toxicant doses in the working area there were used the “standard” indices ofpulmonary ventilation for adults, body weight, the work experience in the contact with carcinogens of 30 years, the number of days in the contact of 240, the duration of the working time 8 or 12 hours (in accordance with the working hours) duration. ICR for the Irkutsk population amounted of 3.08E-04, in Shelekhov - 4.8E-05, Sayansk - 1.1E-05. The amount of risk depends on the content offormaldehyde in all territories and chromium VI in cities of Irkutsk and Shelekhov. ICR for workers of basic occupations of studied plants in dozens of times are higher than for the urban population. Priority carcinogens are: chromium VI, nickel, formaldehyde, silicon dioxide -for the aircraft plant employees; 1,2-dichloretan, vinyl chloride - for the workers of vinyl chloride production plant; benzopyrene - for the aluminum smelter workers.
Investigations were carried out on the influence of phospholipid composition of model membranes on the processes of spontaneous lipid transfer between membranes. Acceptor vesicles were prepared from ...phospholipids extracted from plasma membranes of control and ras-transformed fibroblasts. Acceptor model membranes with manipulated levels of phosphatidylethanolamine (PE), sphingomyelin and phosphatidic acid were also used in the studies. Donor vesicles were prepared of phosphatidylcholine (PC) and contained two fluorescent lipid analogues, NBD-PC and N-Rh-PE, at a self-quenching concentration. Lipid transfer rate was assessed by measuring the increase of fluorescence in acceptor membranes due to transfer of fluorescent lipid analogues from quenched donor to unquenched acceptor vesicles. The results showed that spontaneous NBD-PC transfer increased upon fluidization of acceptor vesicles. In addition, elevation of PE concentration in model membranes was also accompanied by an increase of lipid transfer to all series of acceptor vesicles. The results are discussed with respect to the role of lipid composition and structural order of cellular plasma membranes in the processes of spontaneous lipid exchange between membrane bilayers.
The hygienic assessment of working conditions of employees exposed to local vibration established that working conditions for employees ofvibration dangerous occupations at the aircraft plant ...according to the degree from a health standpoint and hazard are referred to the fourth (dangerous) class of the degree of danger that stipulates stable high levels of the morbidity rate. The leading factor is a local vibration that results in the consistently high levels of occupational morbidity rate. There was shown the efficiency of the use of the pulsed magnetic stimulation in the treatment ofpatients with vibration disease associated with the exposure to local vibration. For the evaluation of the effectiveness of treatment in patients the condition of the central nervous system was determined with the use of computer electroencephalography with the registration of visual and auditory evoked potentials and somatosensory evoked potentials; there was studied the state of the peripheral nerves in arms and legs relying upom electromyographic data; there was performed psychological study. After the performance of pulse magnetic stimulation in patients diagnosed to have the vibration diseases there were observed the improvement in the interaction of cortical-subcortical structures and associative areas of the frontal and temporal lobes of the brain. After treatment there was noted the shortening of the time of the conduction of the afferent wave of the excitation at the level of the cervical spinal cord, subcortical structures and the central conduction time. There was restored previously reduced the speed of the conduction of the impulse via the distal parts of the tibial and median nerve, through the ulnar nerve in the area of the elbow joint. There was noted the rise in the average temperature on the hands; the decline of thresholds of vibration and pain sensitivity; the improvement of indices characterizing of the state of mnestic- attentional and psycho-emotional scope of activity.
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