Observation of Josephson coupling through an interlayer of antiferromagnetically ordered chromium

The supercurrent transport in metallic Josephson tunnel junctions with an additional interlayer made up by chromium, being an itinerant antiferromagnet, was studied. Uniform Josephson coupling was observed as a function of the magnetic field. The supercurrent shows a weak dependence on the interlayer thickness for thin chromium layers and decays exponentially for thicker films. The diffusion constant and the coherence length in the antiferromagnet were estimated. The antiferromagnetic state of the barrier was indirectly verified using reference samples. Our results are compared to macroscopic and microscopic models.Comment: Phys. Rev. B (2009), in prin

Enhancement of the Josephson current by magnetic field in superconducting tunnel structures with paramagnetic spacer

The dc Josephson critical current of a (S/M)IS tunnel structure in a parallel magnetic field has been investigated (here S is a superconductor, S/M is the proximity coupled S and paramagnet M bilayer and I is an insulating barrier). We consider the case when, due to the Hund's rule, in the M metal the effective molecular interaction aligns spins of the conducting electrons antiparallel to localized spins of magnetic ions. It is predicted that for tunnel structures under consideration there are the conditions when the destructive action of the internal and the applied magnetic fields on Cooper pairs is weakened and the increase of the applied magnetic field causes the field-induced enhancement of the tunnel critical current. The experimental realization of this interesting effect of the interplay between superconductivity and magnetism is also discussed.Comment: 5 pages 3 figure

Candidate genes for productivity identified by genome-wide association study with indicators of class in the Russian meat merino sheep breed

Genome-wide association studies allow identification of loci and polymorphisms associated with the formation of relevant phenotypes. When conducting a full genome analysis of sheep, particularly promising is the study of individuals with outstanding productivity indicators – exhibition animals, representatives of the super-elite class. The aim of this study was to identify new candidate genes for economically valuable traits based on the search for single nucleotide polymorphisms (SNPs) associated with belonging to different evaluation classes in rams of the Russian meat merino breed. Animal genotyping was performed using Ovine Infinium HD BeadChip 600K DNA, association search was performed using PLINK v. 1.07 software. Highly reliable associations were found between animals belonging to different evaluation classes and the frequency of occurrence of individual SNPs on chromosomes 2, 6, 10, 13, and 20. Most of the substitutions with high association reliability are concentrated on chromosome 10 in the region 10: 30859297–31873769. To search for candidate genes, 15 polymorphisms with the highest association reliability were selected (–log10(р) > 9). Determining the location of the analyzed SNPs relative to the latest annotation Oar_rambouillet_v1.0 allowed to identify 11 candidate genes presumably associated with the formation of a complex of phenotypic traits of animals in the exhibition group: RXFP2, ALOX5AP, MEDAG, OPN5, PRDM5, PTPRT, TRNAS-GGA, EEF1A1, FRY, ZBTB21-like, and B3GLCT-like. The listed genes encode proteins involved in the control of the cell cycle and DNA replication, regulation of cell proliferation and apoptosis, lipid and carbohydrate metabolism, the development of the inflammatory process and the work of circadian rhythms. Thus, the candidate genes under consideration can influence the formation of exterior features and productive qualities of sheep. However, further research is needed to confirm the influence of genes and determine the exact mechanisms for implementing this influence on the phenotype

Inhomogeneous magnetism induced in a superconductor at superconductor-ferromagnet interface

We study a magnetic proximity effect at superconductor (S) - ferromagnet (F) interface. It is shown that due to an exchange of electrons between the F and S metals ferromagnetic correlations extend into the superconductor, being dependent on interface parameters. We show that ferromagnetic exchange field pair breaking effect leads to a formation of subgap bands in the S layer local density of states, that accommodate only one spin-polarized quasiparticles. Equilibrium magnetization leakage into the S layer as function of SF interface quality and a value of ferromagnetic interaction have also been calculated. We show that a damped-oscillatory behavior versus distance from SF interface is a distinguished feature of the exchange-induced magnetization of the S layer.Comment: 10 pages, 7 Postscript figure

Визначення вмісту антоціанів і танінів у аронії чорноплідної плодах

Introduction. Aronia melanocarpa is widely cultivated in Ukraine as a food, medicinal and ornamental plant. The quality of fresh fruit of Aronia melanocarpa was regulated by the requirements of the pharmaceutical article 42-66-87 "Fresh fruit of Aronia melanocarpa", but the article required a revision using modern approaches to the standardization of medicinal plant material.The aim of the study – determination of the content of anthocyanins and tannins in fresh and dried fruit of Aronia melanocarpa for inclusion the results of the research in the section of the monograph "Quantitative determination".Research Methods. The determination of the content of anthocyanins and tannins in fresh and dried fruit of Aronia melanocarpa was carried out by the method of absorption spectrophotometry.Results and Discussion. The content of anthocyanins in fresh fruit of Aronia melanocarpa is from (0.45±0.01) % to (0.56±0.02) % in terms of cyanidin-3-O-glucoside chloride, the content of tannins in dried fruit of Aronia melanocarpa is from (1.51±0.02) % to (2.41±0.03) % in terms of pyrogallol and dry raw materials. Therefore we proposed to enter the indicator: the content of anthocyanins – at least 0.40 % in terms of cyanidin-3-O-glucoside chloride to the national monograph "Fresh fruit of Aronia melanocarpaN", and the indicator: the content of tannins – not less than 1.5 % in terms of pyrogallol and dry raw materials to the national monograph "Dried fruit of Aronia melanocarpaN".Conclusion. By the method of absorption spectrophotometry in fresh fruit of Aronia melanocarpa the content of anthocyanins was determined, in dried fruit of Aronia melanocarpa – tannins. The results of the research were used during the development of the national monographs "Fresh fruit of Aronia melanocarpaN" and "Dried fruit of Aronia melanocarpaN".Вступление. Арония черноплодная (Aronia melanocarpa) широко культивируется в Украине как пищевое, лекарственное и декоративное растение. Качество плодов аронии черноплодной свежих регламентировалось требованиями ФС 42-66-87 “Плоды аронии черноплодной (рябины черноплодной) свежие”, однако статью необходимо было пересмотреть с использованием современных подходов к стандартизации лекарственного растительного сырья.Цель исследования – определить содержание антоцианов и танинов в плодах аронии черноплодной свежих и высушенных для включения результатов исследований в раздел монографии “Количественное определение”.Методы исследования. Содержание антоцианов и танинов в аронии черноплодной плодах свежих и высушенных определяли методом абсорбционной спектрофотометрии.Результаты и обсуждение. Содержание антоцианов в аронии черноплодной плодах свежих составляет от (0,45±0,01) до (0,56±0,02) % в пересчете на цианидин-3-O-глюкозида хлорид, содержание таниновв аронии черноплодной плодах высушенных – от (1,51±0,02) до (2,41±0,03) % в пересчете на пирогаллол и сухое сырье. Поэтому в национальную монографию “Аронии (рябины) черноплодной плоды свежиеN”предложено ввести показатель: содержание антоцианов – не менее 0,40 % в пересчете на цианидин-3-O-глюкозида хлорид, а в национальную монографию “Аронии (рябины) черноплодной плоды высушенныеN” – показатель: содержание танинов – не менее 1,5 % в пересчете на пирогаллол и сухое сырье.Вывод. Методом абсорбционной спектрофотометрии в плодах аронии черноплодной свежих определено содержание антоцианов, в плодах аронии черноплодной высушенных – танинов. Результаты исследований использовано при разработке национальных монографий “Аронии (рябины) черноплодной плоды свежиеN” и “Аронии (рябины) черноплодной плоды высушенныеN”.Вступ. Аронія чорноплідна (Aronia melanocarpa) широко культивується в Україні як харчова, лікарська і декоративна рослина. Якість аронії чорноплідної плодів свіжих регламентувалася вимогами ФС 42-66-87 “Плоди аронії чорноплідної (горобини чорноплідної) свіжі”, проте статтю треба було переглянути з використанням сучасних підходів до стандартизації лікарської рослинної сировини.Мета дослідження – визначити вміст антоціанів і танінів у аронії чорноплідної плодах свіжих та висушених для включення результатів досліджень до розділу монографії “Кількісне визначення”.Методи дослідження. Вміст антоціанів і танінів в аронії чорноплідної плодах свіжих та висушених визначали методом абсорбційної спектрофотометрії.Результати й обговорення. Вміст антоціанів у аронії чорноплідної плодах свіжих становить від (0,45±0,01) до (0,56±0,02) % у перерахунку на ціанідин-3-O-глюкозиду хлорид, вміст танінів у аронії чорноплідної плодах висушених – від (1,51±0,02) до (2,41±0,03) % у перерахунку на пірогалол і суху сировину. Тому до національної монографії “Аронії (горобини) чорноплідної плоди свіжіN” запропоновано ввести показник: вміст антоціанів – не менше 0,40 % у перерахунку на ціанідин-3-O-глюкозиду хлорид, а до національної монографії “Аронії (горобини) чорноплідної плоди висушеніN” – показник: вміст танінів – не менше 1,5 % у перерахунку на пірогалол і суху сировину.Висновок. Методом абсорбційної спектрофотометрії в аронії чорноплідної плодах свіжих визначено вміст антоціанів, у аронії чорноплідної плодах висушених – танінів. Результати досліджень використано при розробці національних монографій “Аронії (горобини) чорноплідної плоди свіжіN” й “Аронії (горобини) чорноплідної плоди висушеніN”

Feasibility of study magnetic proximity effects in bilayer "superconductor/ferromagnet" using waveguide-enhanced Polarized Neutron Reflectometry

A resonant enhancement of the neutron standing waves is proposed to use in order to increase the magnetic neutron scattering from a "superconductor/ferromagnet"(S/F) bilayer. The model calculations show that usage of this effect allows to increase the magnetic scattering intensity by factor of hundreds. Aspects related to the growth procedure (order of deposition, roughness of the layers etc) as well as experimental conditions (resolution, polarization of the neutron beam, background etc) are also discussed. Collected experimental data for the S/F heterostructure Cu(32nm)/V(40nm)/Fe(1nm)/MgO confirmed the presence of a resonant 60-fold amplification of the magnetic scattering.Comment: The manuscript of the article submitted to Crysstalography Reports. 23 pages, 5 figure

Effectiveness of immunobloting method in syphilis differential diagnostics in pregnancy

168 pregnant women suspected to be infected with syphilis were observed within this research. To prove the presence of antibody in whey blood to antigenes Treponema pallidum we used sets recomBlot Treponema IgM and recomBlot Treponema IgG («Microgen», Germany). In immunological observations the following indexes were included defining number of lymphocyte subpopulations (CD3+ -, CD4+ -, CD8+ -, CD16+ – , CD19+ и CD25+ – lymphocyte) and level in blood serum Interleukin-1β, Interleukin-2, Interleukin-4, Interleukin-8 и INF-γ. Treponema tests in 100% of cases showed positive results, regardless of patients’ category. An examination of pregnant women with serum resistance the immunobloting sensitivity for detecting IgG-antibodies was 61,6%. In 38,4% of cases bloting showed uncertain results, because it detected antibodies to only one or two out of 5 treponemnyh antigens. Level of INF-γ for pregnant women with serum resistance increases, this reflects predominance of immune regulation of Th-1 type. Based on the results we offer general scheme of dealing with pregnant patients with suspected syphilis. These results can be used for differential diagnosis of latent syphilis, and serum resistance

Proximity and Josephson effects in superconductor - antiferromagnetic Nb / \gamma-Fe50Mn50 heterostructures

We study the proximity effect in superconductor (S), antiferromagnetic (AF) bilayers, and report the fabrication and measurement of the first trilayer S/AF/S Josephson junctions. The disordered f.c.c. alloy \gamma-Fe50Mn50 was used as the AF, and the S is Nb. Micron and sub-micron scale junctions were measured, and the scaling of $J_C (d_AF)$ gives a coherence length in the AF of 2.4 nm, which correlates with the coherence length due to suppression of $T_C$ in the bilayer samples. The diffusion constant for FeMn was found to be 1.7 \times 10$^{-4}$ m$^2$ s$^-1$, and the density of states at the Fermi level was also obtained. An exchange biased FeMn/Co bilayer confirms the AF nature of the FeMn in this thickness regime.Comment: 6 pages, 5 figures, accepted for Phys. Rev.

Josephson effect in double-barrier superconductor-ferromagnet junctions

We study the Josephson effect in ballistic double-barrier SIFIS planar junctions, consisting of bulk superconductors (S), a clean metallic ferromagnet (F), and insulating interfaces (I). We solve the scattering problem based on the Bogoliubov--de Gennes equations and derive a general expression for the dc Josephson current, valid for arbitrary interfacial transparency and Fermi wave vectors mismatch (FWVM). We consider the coherent regime in which quasiparticle transmission resonances contribute significantly to the Andreev process. The Josephson current is calculated for various parameters of the junction, and the influence of both interfacial transparency and FWVM is analyzed. For thin layers of strong ferromagnet and finite interfacial transparency, we find that coherent (geometrical) oscillations of the maximum Josephson current are superimposed on the oscillations related to the crossover between 0 and $\pi$ states. For the same case we find that the temperature-induced $0-\pi$ transition occurs if the junction is very close to the crossovers at zero temperature.Comment: 13 pages, 6 figure

Manifestation of triplet superconductivity in superconductor-ferromagnet structures

We study proximity effects in a multilayered superconductor/ferromagnet (S/F) structure with arbitrary relative directions of the magnetization ${\bf M}$. If the magnetizations of different layers are collinear the superconducting condensate function induced in the F layers has only a singlet component and a triplet one with a zero projection of the total magnetic moment of the Cooper pairs on the ${\bf M}$ direction. In this case the condensate penetrates the F layers over a short length $\xi_J$ determined by the exchange energy $J$. If the magnetizations ${\bf M}$ are not collinear the triplet component has, in addition to the zero projection, the projections $\pm1$. The latter component is even in the momentum, odd in the Matsubara frequency and penetrates the F layers over a long distance that increases with decreasing temperature and does not depend on $J$ (spin-orbit interaction limits this length). If the thickness of the F layers is much larger than $\xi_J$, the Josephson coupling between neighboring S layers is provided only by the triplet component, so that a new type of superconductivity arises in the transverse direction of the structure. The Josephson critical current is positive (negative) for the case of a positive (negative) chirality of the vector ${\bf M}$. We demonstrate that this type of the triplet condensate can be detected also by measuring the density of states in F/S/F structures.Comment: 14 pages; 9 figures. Final version, to be published in Phys. Rev.