Practical thermodynamics of Yukawa systems at strong coupling

Simple practical approach to estimate thermodynamic properties of strongly coupled Yukawa systems, in both fluid and solid phases, is presented. The accuracy of the approach is tested by extensive comparison with direct computer simulation results (for fluids and solids) and the recently proposed shortest-graph method (for solids). Possible applications to other systems of softly repulsive particles are briefly discussed.Comment: Published in J. Chem. Phy

The Capacitive Magnetic Field Sensor

The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 < [the empty set] <= 56, 45 < [the empty set] <= 50, 40 < [the empty set] <=45 and [the empty set] <= 40 micron of nanocrystalline alloy of brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented

Relationship of internal and interpersonal trust technical university students

Стаття присвячена дослідженню ролі і місця довіри між учасниками освітнього процесу у технічному вищому навчальному закладі. У запропонованій статті обґрунтовано актуальність дослідження проблеми встановлення довірчих відносин у навчальному процесі. Розглянуто сутність поняття довіри в найбільш авторитетних тлумачних, психологічних словниках та енциклопедіях. Проаналізовано стан вивченості явища довіри у вітчизняній та закордонній літературі. Наведено огляд останніх досягнень у вивченні феномену довіри в україно-, російсько- та англомовних літературних джерелах. Проаналізовано здобутки вітчизняних науковців щодо дослідження особливостей встановлення довіри в процесі навчання та викладання. Матеріали статті торкаються питання про види і типи довіри залежно від різних галузей психологічної науки, в межах яких вона вивчається. Сформульовано завдання, описано методику та процедуру проведення дослідження психологічних особливостей прояву довіри студентів технічного ВНЗ, зокрема кореляційного зв’язку між рівнем соціальної довіри студентів та локусом особистісного контролю. Стаття містить результати проведеного дослідження, представлені у вигляді графіків і таблиць. За результатами дослідження зроблено відповідні висновки.The article deals with the role and place of trust between the participants in the educational process in the technical colleges. In this article the relevance of studying the problem of establishing trust in the educational process. The essence of the concept of trust in the most authoritative explanatory, psychological, dictionaries and encyclopedias. The state of the study of the phenomena of trust in domestic and foreign literature. An overview of recent advances in the study of the phenomenon of trust in the Ukrainian-, Russian- and English-language literature. Analyzed the achievements of domestic scientists to study the features to build trust in the process of teaching and learning. Material of the paper dealt with the issue of the range and types of trust, depends on various branches of psychology, in which it is being studied. The problems, described a method and procedure for the study of psychological features of their confidence technical college students, in particular, the correlation between the level of social trust in students and locus of personal control. The article contains the results of the research presented in graphs and tables. According to a study made by the appropriate conclusions

Possible zoonotic viral threats associated with bats in southern Ukraine

The paper is devoted to evaluation of some bat species inhabiting Ukraine as potential reservoir hosts of highly dangerous viruses including lyssaviruses, MERS-CoV-related coronaviruses, and arboviruses. Repeated catches of bats by a domestic cat were described. Laboratory examination of the caught bats did not detect infection with coronaviruses or arboviruses such as West Nile, tick-borne encephalitis, Crimean-Congo hemorrhagic fever, Tribec and Uukuniyemi viruses. The analysis of the literature showed the possibility of persistence of dangerous viruses among examined bat species. The fact that domestic cats may prey on bats that are potential reservoir hosts of dangerous viruses should be considered as a risk factor for infection of humans and cats with lyssaviruses causing rabies, and infection of humans with coronaviruses that may be associated with severe respiratory diseases.Повідомлення присвячено оцінці ролі деяких видів кажанів, що населяють південь України, як потенційних резервуарів особливо небезпечних вірусів — ліссавірусів, коронавірусів, споріднених з вірусом близькосхідного респіраторного синдрому, та арбовірусів. Описано повторні випадки вилову кажанів свійським котом. Лабораторне обстеження відловлених котом кажанів не виявило наявності у них коронавірусів і таких арбовірусів, як віруси Західного Нілу, кліщового енцефаліту, Кримської-Конго геморагічної гарячки, Трибеч та Уукуніємі. Проведений аналіз даних з літератури свідчить про можливость персистенції небезпечних вірусів серед обстеженних видів кажанів. Той факт, що домашні коти можуть полювати на кажанів як потенційних резервуарів (носіїв) небезпечних вірусів, слід розглядати як фактор ризику для зараження людей та котів ліссавірусами, які викликають сказ, а людей — коронавірусами, що можуть спричиняти важкі респіраторні захворювання

Collective modes of two-dimensional classical Coulomb fluids

Molecular dynamics simulations have been performed to investigate in detail collective modes spectra of two-dimensional Coulomb fluids in a wide range of coupling. The obtained dispersion relations are compared with theoretical approaches based on quasi-crystalline approximation (QCA), also known as the quasi-localized charge approximation (QLCA) in the plasma-related context. An overall satisfactory agreement between theory and simulations is documented for the longitudinal mode at moderate coupling and in the long-wavelength domain at strong coupling. For the transverse mode, satisfactory agreement in the long-wavelength domain is only reached at very strong coupling, when the cutoff wave-number below which shear waves cannot propagate becomes small. The dependence of the cutoff wave-number for shear waves on the coupling parameter is obtained.Comment: 10 pages, 6 figure

Expression of Tumor Assosiated and Epithelial-mesenchymal Transition Markers in 2d and 3d Cell Cultures of Mcf-7

The target effects on the expression of epithelial-mesenchymal transition regulation molecules are promising for cancer therapy, including breast cancer. 3D cell culture is a model for studying epithelial-mesenchymal transition in vitro and may become a test system for anticancer therapy.Aim of research. The aim of this research was to evaluate and compare the expression of tumor associated and epithelial-mesenchymal transition markers in tumor cells of breast adenocarcinoma (MCF-7 cell line) in 2D and 3D cell culture.Methods. For realization of the aim MCF-7 cell line (breast adenocarcinoma) was chosen as an experimental model in vitro. The monolayer cell culture was cultured in standard conditions (37 0C, 5 % CO2, humidity 95 %). The initial density of inoculated cells was 2 x 104 cells/cm2. The cells were incubated for two days before their use in the experiment. For the initial generation of spheroids the monolayer cell culture was removed off the substrate after the four days of incubation, using 0,25 % Trypsin-EDTA, and placed in nutrient medium with 5 % carboxymethyl cellulose (Bio-Rad, USA) at concentration of 5 x 105 cells/ml. Then the plates were incubated on an orbital shaker (Orbital shaker, PSU-10i, Biosan, Latvia) at 50 rpm for 3–5 hours. Half of culture medium was replenished every 3 days. A spheroid culture was maintained for 14 days. Detection of markers (ER, p53, EpCAM, vim, AE1/AE3, panCK, EGFR) in 2D and 3D cell culture was performed using immunohistochemistry method with primary monoclonal antibodies. Histological samples of cells were photographed to compare the morphological characteristics and the expression of proteins in monolayer and spheroid cultureResults. The results demonstrated that the percentage of tumor marker positive cells (ER+, EGFR+, EpCAM+, panCK+, AE1/AE3+) in monolayer culture is 1.25–2 times than more in spheroid culture. In contrast, tumor spheroids consist of fewer cells with the expression of epithelial markers such as EpCAM and AE1/AE3, but they contain a large number of cells that expressed mesenchymal marker vimentin by 5 % and p53 by 10 %. This may indicate that the cells acquire a mesenchymal phenotype. However, tumor cells of monolayer cell culture were not expressed vimentin.Conclusions. Our results demonstrated the differences of expression of tumor associated and epithelial-mesenchymal transition markers in 2D and 3D breast cancer cell cultures. Thus, the percentage of epithelial markers (Cytokeratines and epithelial cell adhesion molecule) in tumor spheroids is less than in cells of monolayer however spheroids cells begin expressing a mesenchymal marker – vimentin. In 3D cell culture only the outer cell layers expressed tumor associated proteins unlike 2D cell culture in which all of cells showed equally expression. Reduced of manifestation of tumor associated markers in 3D cell culture may indicate an increase of stem properties. These data showed that 3D cell culture more than 2D cell culture characterized processes of epithelial-mesenchymal transition

Effect of plasma resonances on dynamic characteristics of double graphene-layer optical modulator

We analyze the dynamic operation of an optical modulator based on double graphene-layer(GL) structure utilizing the variation of the GL absorption due to the electrically controlled Pauli blocking effect. The developed device model yields the dependences of the modulation depth on the control voltage and the modulation frequency. The excitation of plasma oscillations in double-GL structure can result in the resonant increase of the modulation depth, when the modulation frequency approaches the plasma frequency, which corresponds to the terahertz frequency for the typical parameter values.Comment: 8 pages, 4 figure