Magnetic interactions in EuTe epitaxial layers and EuTe/PbTe superlattices

The magnetic properties of antiferromagnetic (AFM) EuTe epitaxial layers and short period EuTe/PbTe superlattices (SLs), grown by molecular beam epitaxy on (111) BaF$_2$ substrates, were studied by magnetization and neutron diffraction measurements. Considerable changes of the N\'eel temperature as a function of the EuTe layer thickness as well as of the strain state were found. A mean field model, taking into account the variation of the exchange constants with the strain-induced lattice distortions, and the nearest neighbor environment of a Eu atoms, was developed to explain the observed $T_{\text N}$ changes in wide range of samples. Pronounced interlayer magnetic correlations have been revealed by neutron diffraction in EuTe/PbTe SLs with PbTe spacer thickness up to 60 \AA. The observed diffraction spectra were analyzed, in a kinematical approximation, assuming partial interlayer correlations characterized by an appropriate correlation parameter. The formation of interlayer correlations between the AFM EuTe layers across the nonmagnetic PbTe spacer was explained within a framework of a tight-binding model. In this model, the interlayer coupling stems from the dependence of the total electronic energy of the EuTe/PbTe SL on the spin configurations in adjacent EuTe layers. The influence of the EuTe and PbTe layer thickness fluctuations, inherent in the epitaxial growth process, on magnetic properties and interlayer coupling is discussed.Comment: 17 pages, 19 figures, accepted to PR

Methodology and principles of assets allocation

Every year the number of those wishing to dive in investments is growing at exponential way. In despite of situation in 2020 many people could efficiently use this time, and some of them could even reserve the assets. But now the other challenge is arisen, how should the assets be invested in an effective way using all power of modern financial markets? The slight knowledge intended for experienced people are presented in the most books, articles and manuals. But how the novice investors should manage which do not see the difference between stock and bond, and the “diversification” word ignites panic-driven fear and discourages from development in this area. The material helping every of those wishing to start without fear and doubts the diving in investment from the very beginning is presented in this work. The main classes of assets with which the Wall Street’s financial experts work, principles for assets allocation and methods helping to choose the optimal model for profit-risk calculation are described in this article

Паліативна допомога при ко-інфекції туберкульоз/ВІЛ. Частина 3

-Учебно-методическое пособие «Паллиативная помощь при ко-инфекции туберкулез ВИЧ» содержит современные базовые сведения о предоставлении паллиативной помощи при сочетанной инфекции туберкулез/ВИЧ, представление которых построено по синдромальному принципу. Представлены вопросы психологической поддержки больных и их близких в рамках паллиативной помощи. Кроме того, особое внимание уделено вопросам ухода за больными непосредственно перед смертью. Пособие может быть рекомендован для обучения студентов, интернов и врачей различных специальностей.Навчально-методичний посібник «Паліативна допомога при ко-інфекції туберкульоз/ВІЛ» містить сучасні базові відомості щодо надання паліативної допомоги при ко-інфекції туберкульоз/ВІЛ, викла-дення яких побудовано за синдромальним принципом. Представлені питання психологічної підтримки хворих та їх близьких у рамках паліативної допомоги. Крім того, окрема увага приділена питанням догляду за хворими безпосередньо перед смертю. Посібник може бути рекомендований для навчання студентів, інтернів та лікарів різних спеціальностей

Comparative Study of the Abscisic Acid Metabolism Using Analogue Tritium-Labeled in the Cyclohexene or Side Moiety

© 2020, Pleiades Publishing, Ltd. Abstract: A procedure was developed for introducing tritium into the side chain of the abscisic acid (ABA) molecule. The reaction was carried out in dioxane in the presence of the Lindlar catalyst. The yield of the labeled product was 70% and the molar radioactivity was 44 Ci/mol. The tritium-labeled abscisic acid analogue was found to be a growth substrate for soil bacteria that incorporate a radioactive label into cellular metabolites. The absorption of the label by bacteria from the side chain of abscisic acid is more than an order of magnitude higher than that for labeling in the cyclohexene moiety. The results indicate the existence of a previously unknown metabolism pathway of ABA in microorganisms

Metabolism by Rhizobacteria of Abscisic Acid Deuterated in the Cyclohexene Part

The required amount of abscisic acid containing 4 – 5 D atoms ([2H]ABA) in the cyclohexene fragment of the molecule was produced via isotope exchange in 100% deuterated D2O at 220°C in the presence of diisopropyl ethylamine. The yield of labeled compound was 45 – 80%. A complex of biological studies was carried out using the D-labeled preparation. It was established that [2H]ABAserved as a growth substrate for soil bacteria, which included the isotopic label in the composition of cell metabolites. The characteristics of D-labeled metabolites allowed their reliable identification in mass spectra of the total bacterial metabolome. Three intermediates of a new metabolic pathway of microbial degradation of this phytohormone were identified using the developed technique

Rhizosphere bacterium rhodococcus sp. P1y metabolizes ab-scisic acid to form dehydrovomifoliol

The phytohormone abscisic acid (ABA) plays an important role in plant growth and in response to abiotic stress factors. At the same time, its accumulation in soil can negatively affect seed germination, inhibit root growth and increase plant sensitivity to pathogens. ABA is an inert compound resistant to spontaneous hydrolysis and its biological transformation is scarcely under-stood. Recently, the strain Rhodococcus sp. P1Y was described as a rhizosphere bacterium assimilat-ing ABA as a sole carbon source in batch culture and affecting ABA concentrations in plant roots. In this work, the intermediate product of ABA decomposition by this bacterium was isolated and purified by preparative HPLC techniques. Proof that this compound belongs to ABA derivatives was carried out by measuring the molar radioactivity of the conversion products of this phytohor-mone labeled with tritium. The chemical structure of this compound was determined by instrumen-tal techniques including high-resolution mass spectrometry, NMR spectrometry, FTIR and UV spec-troscopies. As a result, the metabolite was identified as (4RS)-4-hydroxy-3,5,5-trimethyl-4-[(E)-3-oxobut-1-enyl]cyclohex-2-en-1-one (dehydrovomifoliol). Based on the data obtained, it was con-cluded that the pathway of bacterial degradation and assimilation of ABA begins with a gradual shortening of the acyl part of the molecule