Saturation effect for dependence of the electrical conductivity of planar oriented nematic liquid crystal 6CB on the concentration of Cu7PS6 nanoparticles

The influence of Cu7PS6 nanoparticles with the average size 117 nm on the dielectric properties of planar oriented nematic liquid crystal 6CB has been investigated within the frequency range 10(1) ...10(6) Hz and at the temperature 293 K. It has been shown that when changing the concentration of nanoparticles within the range 0 to 1 wt.%, the conductivity of the liquid crystal changes stronger than its dielectric permittivity. It has been shown that the electrical conductivity increases monotonously with increasing the concentration of nanoparticles. However, for this dependence a saturation effect is observed. The mechanism of this effect was proposed.info:eu-repo/semantics/publishedVersio

Crucial Role for Early Growth Response-1 in the Transcriptional Regulation of miR-20b in Breast Cancer

Transcriptional regulation of miRNAs that control the pathogenesis of breast cancer remains largely unknown. Here, we showed that ionizing radiation, a known breast carcinogen, triggered the differential expression of miR-20b in mammary tissues. We identified several GC-rich consensus binding motifs for the zinc finger transcription factor early growth response-1 (EGR1) in miR-20b promoter. miR-20b was upregulated by IR and its upregulation correlated with EGR1 expression in the breast cancer cell line HCC1806. Therefore, we used HCC1806 cells as a model system to explore the role of EGR1 in miR-20b transcription. siRNA knockdown of EGR1 attenuated miR-20b expression. Luciferase assays showed that whereas EGR1 stimulated luciferase activity driven by the wild-type miR-20b promoter, this induction was abolished in the mutant miR-20 promoter construct. We noted significant enrichment of EGR1 at miR-20b promoter in HCC1806 cells compared with normal human mammary epithelial cells. Suppression of miR-20b significantly inhibited HCC1806 cell proliferation and migration, and led to G 0/G 1 and S phase arrest. In vitro RNA-pull down assays indicated that miR-20b targets numerous tumor suppressors, including PTEN and BRCA1, which were downregulated in HCC1806. Conversely, suppression of miR-20b increased PTEN and BRCA1 levels. Moreover, immunohistochemical and FISH analyses showed that the miR-20b expression correlated significantly with EGR1 levels in breast cancer tissues. Our findings thus demonstrate for the first time that EGR1 is a key player in the transcriptional control of miR-20b, and miR-20b may in turn function as an oncogene by contributing to breast tumorigenesis via tumor suppressor targeting

Dynamics of erosion-accumulation processes along the stream bed of Turiya river (Kovel hydropost)

The article reflects the results of the study of deformations of the stream bed of the Turiya River (Kovel Hydropost, hydro range No. 5) during 1983–2018. For this purpose, multiple cross-sections of the channel and various combined flow curves were constructed and analyzed, the levels of water in the river, the relationships between the course of erosion-accumulation processes along the course and the dynamics of natural and anthropogenic factors are revealed. The information base of the study was the theoretical basis of the doctrine of channel processes, which are substantiated in the works of foreign and Ukrainian scientists, the materials of our own observations, data from the Volyn Center for Hydrology and Meteorology (hereinafter VCGM). In the process of solving the tasks, the methods of comparative analysis, synthesis, graphic, mathematical and statistical methods were applied; the system approach was applied. During the study it was established that during the specified time interval in the stream bed there was an alternation of erosion and accumulation processes, which was expressed by the alternation of periods of some erosion of the stream bed and its siltation. The transverse profiles of the Turiya stream bed indicate that during the period 1983–1988, mainly accumulative processes prevailed in the channel, and in the following period (1988–2008) they changed to erosion ones. In recent years, rechargeable processes have become dominant and the profile of the stream bed in 2018 has come closer to its stream bed in 1988. The flow and water level curves of Turiya confirm our conclusions about trends in erosion-accumulation processes along the stream bed. During the periods 1983–1988 and 1996–2000, the accumulation processes dominated, and at the interval of time from 1988 to 1996 and in 2000–2008 erosion processes dominated. The 2009, 2012, 2013, 2014, 2017 curves are in almost one field, which attests to the stability of the Turiya River over the last decade. The development of channel deformations depends, mainly, on the hydrological regime of the river. The dynamics of erosion-accumulation processes along the river Turiya is consistent with the long-term regime of its maximum runoff: in the 80-ies of the last century a significant fall in the values of maximum discharge (some decrease in annual precipitation, the influence of the Kovel reservoir) was observed, which led to their erosion. Compared to this time period, around the 1990s and during the 2000s, the values of maximum discharge increased slightly. As a consequence, the eroding ability of the watercourse during floods and freshets increased, which slightly increased the cross-sectional area of the channel. In the last four years, the values of maximum discharge have been significantly lower than normal, and as a result erosion processes have weakened. Reduction of the maximum discharge of the Turiya River, absence of runoff during the 2015–2018 boundary, dominance of accumulative processes in the channel leads to eutrophication of the watercourse, which, in turn, reduces its transport capacity and contributes to the further accumulation of solids. If this trend continues in the future, then the risks of flooding the Turiya floodplains in the event of heavy floods or freshets will increase

Molecular Dynamics Simulation of Sympathetic Crystallization of Molecular Ions

It is shown that the translational degrees of freedom of a large variety of molecules, from light diatomic to heavy organic ones, can be cooled sympathetically and brought to rest (crystallized) in a linear Paul trap. The method relies on endowing the molecules with an appropriate positive charge, storage in a linear radiofrequency trap, and sympathetic cooling. Two well--known atomic coolant species, ${}^9{\hbox{Be}}^+$ and ${}^{137}{\hbox{Ba}}^+$, are sufficient for cooling the molecular mass range from 2 to 20,000 amu. The large molecular charge required for simultaneous trapping of heavy molecules and of the coolant ions can easily be produced using electrospray ionization. Crystallized molecular ions offer vast opportunities for novel studies.Comment: Accepted for publication in Phys. Rev.

Вплив різних рівнів валіну у раціоні на показники забою перепелів

The article presents the expediency of using valine in the feeding of growing quails of meat direction of productivity. The studies were conducted in the conditions of research laboratory of feed additives of National University of Life and Environmental Sciences of Ukraine. The experiment was conducted with growing Pharaoh quails. It was selected 500 daily quails. Birds were placed in 20 cages with 25 heads in each. In the formation of analog groups, the body weight of the birds was taken into account. Quails were fed full-fledged mixed fodder, which was balanced by energy and other nutrients. The feed for the quails of the control group contained the natural level of valine, and the experimental groups – additionally L-valine according to the experimental scheme. Observed a relationship between the level of valine in feed and feed conversion (R2 = 0.7359). The most effective level of valine in mixed fodder for quail, which is grown for meat, to obtain a sufficiently large body weight with a low level of feed intake per unit of growth is at 1– 21-day age – 1.68% and at 22– 35-day age – 1.23%.Обґрунтовано доцільність застосування валіну у годівлі молодняку перепелів м’ясного напряму продуктивності. Дослідження проводились в умовах проблемної науково-дослідної лабораторії кормових добавок Національного університету біоресурсів і природокористування України. Було проведено науково-господарський дослід на молодняку перепелів породи фараон. Для нього було відібрано 500 добових перепелів породи фараон. Птахів розміщували у 20-ти клітках по 25 голів у кожному. При формуванні груп-аналогів враховували масу тіла птиці. Піддослідним перепелам згодовували повнораціонний розсипний комбікорм, який був збалансований за вмістом енергії та іншими поживними речовинами. Комбікорм перепелів контрольної групи містив природній рівень валіну, а дослідних груп – додатково L-валін відповідно до схеми досліджень. Спостерігаються залежність між рівнем валіну у комбікормі та конверсією корму (R2 = 0,7359). Найефективнішим рівнем валіну у комбікормі для перепелів, яких вирощують на м’ясо, для отримання досить великої маси тіла з найнижчим рівнем використання комбікорму на одиницю приросту є у 1–21-добовому віці – 1,68% та у 22–35-добовому віці – 1,23%

Blackbody-radiation-assisted molecular laser cooling

The translational motion of molecular ions can be effectively cooled sympathetically to temperatures below 100 mK in ion traps through Coulomb interactions with laser-cooled atomic ions. The distribution of internal rovibrational states, however, gets in thermal equilibrium with the typically much higher temperature of the environment within tens of seconds. We consider a concept for rotational cooling of such internally hot, but translationally cold heteronuclear diatomic molecular ions. The scheme relies on a combination of optical pumping from a few specific rotational levels into a ``dark state'' with redistribution of rotational populations mediated by blackbody radiation.Comment: 4 pages, 5 figure

Theory and Applications of X-ray Standing Waves in Real Crystals

Theoretical aspects of x-ray standing wave method for investigation of the real structure of crystals are considered in this review paper. Starting from the general approach of the secondary radiation yield from deformed crystals this theory is applied to different concreat cases. Various models of deformed crystals like: bicrystal model, multilayer model, crystals with extended deformation field are considered in detailes. Peculiarities of x-ray standing wave behavior in different scattering geometries (Bragg, Laue) are analysed in detailes. New possibilities to solve the phase problem with x-ray standing wave method are discussed in the review. General theoretical approaches are illustrated with a big number of experimental results.Comment: 101 pages, 43 figures, 3 table

Dielectric and electrical properties of nematic liquid crystals 6CB doped with iron oxide nanoparticles. The combined effect of nanodopant concentration and cell thickness

Dispersing nanomaterials in liquid crystals has emerged as a very promising non-synthetic way to produce advanced multifunctional and tunable materials. As a rule, dielectric and electrical characterization of such materials is performed using cells of single thickness. As a result, the published reports vary even for similar systems. Confusion still exists as to the effects of nanodopants and cell thickness on the dielectric and electrical properties of liquid crystals. This factor hinders a widespread use of liquid crystals – nanoparticles systems in modern tech products. In this paper, we report systematic experimental studies of the combined effect of the cell thickness and iron oxide nanoparticle concentration on the electrical and dielectric properties of nematic liquid crystals 6CB. The measured dielectric spectra can be divided into three distinct regions corresponding to a low frequency (<10 Hz) dispersion, dispersion free range (102 - 104 Hz (electrical conductivity) and 102 - 105 (dielectric permittivity)), and high frequency dispersion (104 - 106 Hz (electrical conductivity) and 105 - 106 Hz (dielectric permittivity)). The real part of the dielectric permittivity is not affected by the cell thickness and its value can be tuned by changing the concentration of nanoparticles. At the same time, the electrical conductivity depends on both cell thickness and nanoparticle concentration. At intermediate frequencies (102 - 104 Hz) the electrical conductivity obeys the Jonscher power law and is dependent on the cell thickness because of ion-releasing and ioncapturing effects caused by nanoparticles and substrates of the cell. In addition, its value is affected by the electronic conductivity due to iron oxide nanoparticles and their nanoclusters. At higher frequencies (104 - 106 Hz) the electrical conductivity follows a super linear power law and is nearly independent of the cell thickness and nanoparticle concentration

Structural and transport properties of GaAs/delta<Mn>/GaAs/InxGa1-xAs/GaAs quantum wells

We report results of investigations of structural and transport properties of GaAs/Ga(1-x)In(x)As/GaAs quantum wells (QWs) having a 0.5-1.8 ML thick Mn layer, separated from the QW by a 3 nm thick spacer. The structure has hole mobility of about 2000 cm2/(V*s) being by several orders of magnitude higher than in known ferromagnetic two-dimensional structures. The analysis of the electro-physical properties of these systems is based on detailed study of their structure by means of high-resolution X-ray diffractometry and glancing-incidence reflection, which allow us to restore the depth profiles of structural characteristics of the QWs and thin Mn containing layers. These investigations show absence of Mn atoms inside the QWs. The quality of the structures was also characterized by photoluminescence spectra from the QWs. Transport properties reveal features inherent to ferromagnetic systems: a specific maximum in the temperature dependence of the resistance and the anomalous Hall effect (AHE) observed in samples with both "metallic" and activated types of conductivity up to ~100 K. AHE is most pronounced in the temperature range where the resistance maximum is observed, and decreases with decreasing temperature. The results are discussed in terms of interaction of 2D-holes and magnetic Mn ions in presence of large-scale potential fluctuations related to random distribution of Mn atoms. The AHE values are compared with calculations taking into account its "intrinsic" mechanism in ferromagnetic systems.Comment: 15 pages, 9 figure

СІМЕЙНО-ОРІЄНТОВАНА МЕДИЦИНА ЯК ВАЖЛИВИЙ НАПРЯМ РОЗВИТКУ ПЕДІАТРИЧНОЇ ДОПОМОГИ В УКРАЇНІ

The article analyzes the experience of implementing family-oriented care in healthcare facilities in North America and Western Europe. It has been shown that the application of this approach can have positive outcomes for both children and their families, and can contribute to improving the efficiency of medical staff and the cost-effectiveness of medical services.У статті проаналізовано досвід впровадження сімейно-орієнтованого догляду в медичних закладах країн Північної Америки та Західної Європи. Показано, що застосування цього підходу може мати позитивні наслідки як для дітей та їхніх сімей, так і сприяти покращенню ефективності роботи медичних кадрів та економічної ефективності медичних послуг