ABSTRACT
Geometry and dynamical structure of emission regions in accreting pulsars are shaped by the interplay between gravity, radiation, and strong magnetic field, which significantly affects the ...opacities of a plasma and radiative pressure under such extreme conditions. Quantitative consideration of magnetic plasma opacities is therefore an essential ingredient of any self-consistent modelling of emission region structure of X-ray pulsars (XRPs). We present results of computations of the Rosseland and Planck mean opacities of a strongly magnetized plasma with a simple chemical composition, namely the solar hydrogen/helium mix. We consider all relevant specific opacities of the magnetized plasma including vacuum polarization effect and contribution of electron–positron pairs where the pair number density is computed in the thermodynamic equilibrium approximation. The magnetic Planck mean opacity determines the radiative cooling of an optically thin strongly magnetized plasma. It is by factor of three smaller than non-magnetic Planck opacity at $k_{\rm B}T \lt 0.1\, E_{\rm cyc}$ and increases by a factor of 102–104 at $k_{\rm B}T \gt 0.3\, E_{\rm cyc}$ due to cyclotron thermal processes. We propose a simple approximate expression which has sufficient accuracy for the magnetic Planck opacity description. We provide the Rosseland opacity in a tabular form computed in the temperature range 1–300 keV, magnetic field range 3 × 1010–1015 G, and a broad range of plasma densities. We demonstrate that the scattering on the electron–positron pairs increases the Rosseland opacity drastically at temperatures > 50 keV in the case of mass densities typical for accretion channel in XRPs.
The emerging and steady increase of microbes that are resistant to antimicrobial treatments has become a global public health concern that threatens the effective treatment of infectious diseases, ...therefore, the development of new medicines with antimicrobial properties is one of the priorities of the health systems.
Cationic detergents, which, as a result of the combination of their surface activity and bactericidal properties, are promising for use in pharmacy and medicine. One of the representatives of the cationic surfactant group is polyhexamethylene guanidine hydrochloride (PGMG-GC) which was shown to be less toxic compared to some other disinfectants and effective against a wide spectrum of microbes.
The aim of the study was to determine the acute toxicity parameters of a highly-dispersive silica (HDS) and PGMG-GC composite in mice after intragastric administration.
The study was carried out on 23 BALB/c female mice weighing 18–22 g. To determine the toxicity, the animals were divided into the following groups. The first group was intragastrically injected with a composite of HDS and PGMG-GH, the second group was given a suspension of HDS, the third group was given a solution of PGMG-GC, and the fourth (control) group was treated with water for injection.
The mass of the animals was determined before and on the 3rd, 7th, and 14th day after the composite administration. Administration of PGMG-GC or PGMG-GC + HDS composite caused significant decrease in body weight at 3rd and 7th day compared to control with further normalization on day 14. No significant changes of body weight were found in HDS group.
No death of mice occurred after a single intragastric injection of the HDS + PGMG-GC composite during 14 days of the study. For the solution of PGMG-GC (without HDS), lethal cases were reported 2 h after the treatment at a dose level of 400 mg/kg. The condition of the animals survived normalized and, by the day 14, it corresponded to that in the control group for the most of the signs of toxicity indicating the reversibility of the toxic effect of PGMG-GC.
Therefore, PGMG-GC is less toxic whet it is used as a part of the composite. Since no lethal cases were reported after a single intragastric administration of the composite at a dose of 2 000 mg/kg of body weight, the composite HDS + PGMG-GC appears to be low toxic according to the classification of substances by toxicity.
Optical sensor arrays are widely used in obtaining fingerprints of samples, allowing for solutions of recognition and identification problems. An approach to extending the functionality of the sensor ...arrays is using a kinetic factor by conducting indicator reactions that proceed at measurable rates. In this study, we propose a method for the discrimination of proteins based on their oxidation by sodium hypochlorite with the formation of the products, which, in turn, feature oxidation properties. As reducing agents to visualize these products, carbocyanine dyes IR-783 and Cy5.5-COOH are added to the reaction mixture at pH 5.3, and different spectral characteristics are registered every several minutes (absorbance in the visible region and fluorescence under excitation by UV (254 and 365 nm) and red light). The intensities of the photographic images of the 96-well plate are processed by principal component analysis (PCA) and linear discriminant analysis (LDA). Six model proteins (bovine and human serum albumins, γ-globulin, lysozyme, pepsin, and proteinase K) and 10 rennet samples (mixtures of chymosin and pepsin from different manufacturers) are recognized by the proposed method. The method is rapid and simple and uses only commercially available reagents.
Optical “fingerprints” are widely used for chemometrics-assisted recognition of samples of different types. An emerging trend in this area is the transition from obtaining “static” spectral data to ...reactions analyzed over time. Indicator reactions are usually carried out in aqueous solutions; in this study, we developed reactions that proceed in an organic solvent, thereby making it possible to recognize fat-soluble samples. In this capacity, we used 5W40, 10W40, and 5W30 motor oils from four manufacturers, with six samples in total. The procedure involved mixing a dye, sample, and reagents (HNO3, HCl, or tert-butyl hydroperoxide) in an ethanolic solution in a 96-well plate and measuring absorbance or near-infrared fluorescence intensity every several minutes for 20–55 min. The obtained photographic images were processed by linear discriminant analysis (LDA) and the k-nearest neighbors algorithm (kNN). Discrimination accuracy was evaluated by a validation procedure. A reaction of oxidation of a dye by nitric acid allowed us to recognize all six samples with 100% accuracy for LDA. Merging of data from the four reactions that did not provide complete discrimination ensured an accuracy of 93% for kNN. The newly developed indicator systems have good prospects for the discrimination of other fat-soluble samples. Overall, the results confirm the viability of the kinetics-based discrimination strategy.
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Nanoparticulate CoFe
2
O
4
has been synthesized by the citrate combustion method. The nanopowder has been characterized from the viewpoint of its chemical homogeneity, particle size, dispersion, ...and morphological features. The results demonstrate that the CoFe
2
O
4
nanopowder (with an average particle size on the order of 74 nm) is an effective catalyst for the oxidation of the organic pollutants methylene orange (degree of destruction of 76.6%) and 2,4-dinitrophenol (degree of destruction of 95.4%) in Fenton-like processes without additional heating or ultraviolet illumination.
In the article Soviet sport of the period of Civil War of 1918–1921 is considered as the socio-political project. The author reveals a role of Universal military education and the Russian communistic ...union of youth in development of Soviet Sport. The article analyses the state concept of sport which is formed together with the young Soviet state comes to light. The author reveals the main problems of Soviet Sport as socio-political project, such as shortage of shots and counterrevolutionary activity of sports clubs. The author concludes that during Civil War Soviet Sport was created as the socio-political project focused on military preparation, improvement of the nation and formation of the new person in the spirit of communistic morals
The article analyses and clarifies the concept of public control over the activities of the National Police in Ukraine. Public control over the activities of the police is defined as a targeted ...activity of the organised and unorganised public regarding the quality of police activities and the effectiveness of the tasks and duties assigned to police representatives. The importance of public control over the activities of law enforcement agencies in terms of building a democratic state with an active civil society is emphasised. Public control is an instrument of public assessment of the implementation of public tasks by law enforcement agencies. Control over the activities of the National Police in Ukraine allows to regulate the relationship between the government and the community, which is an integral feature of all democratic states. The specificity of public control, in comparison with other types of control, is the subject-object sphere, which is manifested in the public's control. In the process of public control, the implementation of social tasks directly related to the protection and realisation of the rights and freedoms of citizens, as well as satisfaction and harmonisation of social needs and interests of the population is monitored. The main forms and subjects of public control are defined. Public control over the activities of the National Police can be carried out by individual and collective, organized and unorganized subjects whose activity profile is general or law enforcement oriented. According to their legal status, the subjects of public control over police activities can be natural or legal entities of private law and associations of citizens without the status of a legal entity. Important subjects of public control over the activities of the National Police in Ukraine are mass media, public councils and public organizations. It has been concluded that public control allows to improve the quality of police activities and to influence the implementation of changes in the activities of the National Police in Ukraine, which is especially important during a full-scale war.
Introduction. The main component of the compound feedstuff is fish meal, which has unstable quality and high price. Fish and meat-and-bone meals are replaced with protein concentrates and higher ...quality larvae proteins. The source of feed protein is the biomass of the black soldier flies (Hermetia illucens), which have a rich amino acid composition and also process food waste. The aim of the work is to study the thermal-physical characteristics of the muscle mass of the black soldier fly larvaes (Hermetia illucens).
Материалы и методы. The study focused on the muscle mass of black soldier fly larvaes (Hermetia illucens). The subject of the study is thermal-physical regularities during the drying process. The studies were conducted on the basis of Don State Technical University. The article describes determination of thermal-physical characteristics such as specific heat, thermal conductivity, moisture of the raw material, and oiliness.
Results. Heat conductivity coefficient of water 0.555 W/(m∙K) for food and feed products from 0.25 to 0.40 W/(m∙K) black Soldier Fly larvae have a heat conductivity equal to 0.144 W/(m∙K), which is lower than conventional feedstuff components. The humidity of the examined raw material is 45% or higher while the heat conductivity remains linear and practically does not increase.
Discussion and Conclusion. The results obtained during the work can be used for parameter determination and design of various types of dryers, and for mathematical description of the dynamics and kinetics of drying.
The average electric polarization arising in a two-layer, nanosized, ferromagnetic film with a combined uniaxial and cubic anisotropy and a vortical distribution of magnetization is studied ...numerically. Allowance for the cubic anisotropy leads to a multifold increase in the average electric polarization in samples with a positive constant of cubic anisotropy and a significant decrease in samples with a negative constant of cubic anisotropy. Analysis of the hysteresis of the average electric polarization in a magnetic field perpendicular to the film revealed striking differences in the field dependences in films with different cubic anisotropy. If the cubic anisotropy is positive, then the maxima of the average polarization curves shift to the region of low magnetic fields upon an increase in the anisotropy constant. The intensity of the maxima becomes larger, and the hysteresis practically disappears. For films with a negative constant of cubic anisotropy, the maxima of the average polarization curves shift to the region of high fields upon an increase in this constant and the intensity of the maxima becomes significantly smaller.
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