Social networks as a tools of learning of the students of secondary vocational education

The article considers use of social networks as tools of learning students of the secondary vocational education. The authors show examples of social networking in education. Also shows examples of the use of social networks in the learning activities of students in the secondary vocational educationВ статье рассматриваются вопросы использования социальных сетей как средство обучения студентов среднего профессионального образования (СПО). Приводятся примеры социальных сетей в образовании, а также примеры использования социальных сетей в учебной деятельности студентов СП

Organizational and activity support of lessons with the application of social media services

The article discusses the use of social services that ensure the quality of the educational process, presents the results of the design of the training session with the use of social servicesВ статье рассмотрены вопросы применения социальных сервисов, обеспечивающих качество организации образовательного процесса, представлены результаты проектирования учебного занятия с применением социальных сервисо

Molecular structure and properties of κ-carrageenan-gelatin gels

© 2018 Elsevier Ltd Rheological studies, FTIR spectroscopy and a molecular docking approach were used to explore the structural basis of the peculiar physicochemical properties of gelatin gels modified with a κ-carrageenan admixture. Mixed gel properties are affected by the polysaccharide-to-gelatin ratio, Z, and can be divided into two categories. At low ratios, the strength of mixed gels varies insignificantly compared to gelatin due to the similar structures of the gels. Above the threshold content of κ-carrageenan (Z > 0.1), the storage modulus and yield stress of mixed gels are significantly enhanced. The nonadditivity and threshold character of the rheological properties could be the result of conformational ordering of both gelatin and κ-carrageenan, leading to the formation of additional junction zones in the gel network. According to molecular docking studies, the junctions could be formed as a result of complementary interactions between the gelatin triple helix and the κ-carrageenan double helix. The stack formation increases the interaction energy, which explains the strengthening of the gel network

Comparative Analysis of the Pathogen Structure in Patients with Community-Acquired and Nosocomial Pneumonia in Medical Organizations of the Rostov, Tyumen Regions and Khabarovsk Territory at the Current Stage of a New Coronavirus Infection Pandemic

The aim of the study was to conduct a comparative analysis of the spectrum and antibiotic resistance of secondary pneumonia pathogens isolated in the territories of the Rostov, Tyumen Regions and Khabarovsk Territory against the background of a new coronavirus infection pandemic.Materials and methods. We investigated sputum samples from coronavirus-positive and coronavirus-negative patients with community-acquired pneumonia from medical organizations using bacteriological method, PCR mass spectrometry.Results and discussion. The study of the etiological structure of secondary pneumonia agents isolated from patients in medical organizations of the Southern, Ural and Far Eastern Federal Districts has revealed that the dominant cultures in SARS‑CoV‑2 “+” and SARS‑CoV‑2 “–” patients were yeast and yeast-like fungi. It has been found that under diversity of isolated fungi, Candida albicans species prevailed. The bacterial microflora is represented by a variety of gram-positive and gram-negative bacteria, of which Staphylococcus aureus and Klebsiella pneumoniaе were most often present in sputum. It has also been established that even before hospitalization of patients, community-acquired pneumonia could be caused by microorganisms of the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniaе, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.), which are usually considered as polyantibiotic-resistant pathogens of nosocomial infections. Moreover, in coronavirus-positive patients with secondary community-acquired pneumonia, those pathogens were isolated 2–3 times more frequently than in coronavirus-negative ones. Assessment of sensitivity/resistance of isolated strains to antibacterial drugs has revealed a general trend: the majority of the strains, regardless of the type, were characterized by a narrow spectrum of sensitivity, having 3 or more markers of antibiotic resistance. This confirms the necessity and expediency of microbiological support of the patient during the entire infectious process. The most adequate drugs of choice, providing activity against 60–70 % of strains of the Enterobacteriaceae family, are amikacin and cefoperazone/sulbactam

Droplet Crystallization in Water-in-Crude Oil Emulsions: Influence of Salinity and Droplet Size

Ice crystallization in confined spherical geometries is investigated experimentally at ambient pressure conditions. Water-in-crude (w/o) oil emulsions are formed by homogenization of an acidic North Sea crude oil with water or brine, at aqueous phase fractions ranging from 1 to 30 wt % and varying electrolyte contents. Ice-in-oil dispersions are formed from the emulsions by cooling, and they provide a justified analogue to gas hydrate formation in water-in-crude oil emulsions, due to analogous wettability conditions that govern agglomeration. Nuclear magnetic resonance (NMR) spectroscopy and digital video microscopy (DVM) imaging establish droplet size distributions (DSDs) and mean droplet diameters, and demonstrate emulsion stability with an absence of coalescence over extended time durations. Differential scanning calorimetry (DSC) establishes the crystallization temperature of the dispersed water droplets. It is demonstrated that the crystallization temperature decreases with a decreasing length scale of the dispersed water droplet phase, in accordance with theoretical knowledge

Molecular structure and properties of κ-carrageenan-gelatin gels

© 2018 Elsevier Ltd Rheological studies, FTIR spectroscopy and a molecular docking approach were used to explore the structural basis of the peculiar physicochemical properties of gelatin gels modified with a κ-carrageenan admixture. Mixed gel properties are affected by the polysaccharide-to-gelatin ratio, Z, and can be divided into two categories. At low ratios, the strength of mixed gels varies insignificantly compared to gelatin due to the similar structures of the gels. Above the threshold content of κ-carrageenan (Z > 0.1), the storage modulus and yield stress of mixed gels are significantly enhanced. The nonadditivity and threshold character of the rheological properties could be the result of conformational ordering of both gelatin and κ-carrageenan, leading to the formation of additional junction zones in the gel network. According to molecular docking studies, the junctions could be formed as a result of complementary interactions between the gelatin triple helix and the κ-carrageenan double helix. The stack formation increases the interaction energy, which explains the strengthening of the gel network

Rheological Properties of Fish Gelatin Modified with Sodium Alginate

Polyelectrolyte complexes of sodium alginate and gelatin obtained from cold-blooded fish were studied for potential application as structure-forming agents in food hydrogels. The mass ratio of sodium alginate to gelatin plays a decisive role in the sol-gel transition and rheological behavior of the complexes. Differences in the sol-gel transition temperature were observed upon heating and cooling, as is typical for such materials. We investigated the characteristics of this transition by measuring the isothermal changes in the elastic modulus over time at a constant frequency and the transition temperature at a range of frequencies. The kinetic nature of this transition depends on the composition of the complexes. A characteristic alginate-gelatin mass ratio is the ratio at which maximum transition temperature as well as elastic modulus and viscosity (rheological parameters) values are obtained; the characteristic mass ratio for these complexes was found to be 0.06. Calculation of the ionic group ratios in the biopolymers that form complexes and comparison of these data with the turbidimetric titration results clarified the origin of these maxima. Measuring the viscoelastic properties and the creep-elastic recoil of the samples allowed us to characterize these materials as viscoelastic media with a viscosity in the order of 103–104 Pa·s and an elastic modulus in the order of 102–103 Pa. These values drastically decrease at a certain stress threshold, which can be treated as the gel strength limit. Therefore, the observed rheological behavior of gels formed by fish gelatin modified with sodium alginate characterizes them as typical viscoelastic soft matter

Kinetics of Crystallization of Aqueous Droplets in Water-in-Crude Oil Emulsions at Low Temperatures

This study focused on the examination of the isothermal crystallization of aqueous droplets in water-in-crude oil emulsions with water concentrations in the range of 5 to 20 wt %. Experiments were carried out using differential scanning calorimetry (DSC) with temperatures ranging from −36 °C to −41 °C. The experimental results were approximated using a mathematical kinetic model including the effect of self-acceleration. The rate of crystallization increases with decreasing temperature, and the final accepted degree of crystallinity also increases along with a decrease in temperature. Correlation was observed between the kinetics of isothermal and nonisothermal crystallization. Furthermore, the complete crystallization in the isothermal process is reached at −40 °C; however, at high rates of cooling (10 to 20 °C/min), complete crystallinity is not achieved even at −50 °C. Complete crystallinity in the nonisothermal process can only be reached at cooling rates lower than 5 °C/min

Chemical composition of Pechora Sea crude oil

The physicochemical properties of the Pechora Sea shelf oil and its chemical composition have been studied using the methods of refractometry, titrimetry, viscometry, rheometry and standard methods for the analysis of oil and petroleum products. The fractionation of oil is held at atmospheric pressure, some fractions boiling at the temperature below and above 211 °C have been received. Chemical structural-group composition of oil and its components has been investigated using a Fourier infrared (IR) spectroscopy method. The density of oil has been obtained, it is equal to 24.2 API. The chemical composition analysis shows that water content in the investigated oil sample is about 0.03 % (by weight). The oil sample contains hydrocarbons (including alkanes, naphthenes, arenes) and asphaltenes with resins; their content is equal to 89 and 10 % (by weight) respectively. Alkane content is about 66 %, including alkanes of normal structure – about 37 %. The solidification temperature of oil sample is equal to –43 °C. This low temperature testifies obliquely low content of solid alkanes (paraffin). Bearing in mind the content of asphaltenes with resins we can refer the investigated oil sample to resinous oils. On the other hand spectral coefficient values (aromaticity quotient and aliphaticity quotient) show that oil sample belongs to naphthenic oils. According to the data of Fourier IR spectroscopy contents of naphthenes and arenes are 5.9 and 17.8 % respectively. Thus, the obtained data of chemical structural-group composition of crude oil and its fractions indicate that this oil belongs to the heavy resinous naphthenic oils. The rheological parameters obtained at the shear deformation conditions characterize the crude oil as a visco-plastic medium