In contrast to the developed areas of the Middle and Southern Urals, the hard-to-reach and eroded northern territories of the Ural folded system remain poorly studied, which determines a large number of unevaluated gold ore occurrences and single industrial objects. The Karyernoe gold ore occurrence is located among the Middle Paleozoic volcanic-clastic rocks of the Toupugol-Khanmeishorsky gold ore district on the eastern slope of the Polar Urals. The volcanic rocks show signs of early stratabound pyrite-like mineralization, which is cut by veins and dikes of the Sobsky (D1-2) and Musyur (C1-2) complexes. A new approach – (U,Th)-He pyrite dating – was used in order to determine the age of the sulfide mineralization of the Karyernoe ore occurrence, located on the flank of the Novogodnee ore field. (U,Th)-He pyrite ages (n=7) varies in a wide range from 402 to 425 Ma. Given the petrographic and mineralogical-geochemical observations, obtained data suggest the presence of at least two stages of rock mineralization: wenlock-ludlow – 424±6 Ma; and a later Early Devonian – 402±6 Ma, which is probably associated with the intrusion of Sob complex granitoids into the rocks of the Toupugolskaya formation. The obtained ages of the sulfide mineralization of the Karyernoe ore occurrence are significantly older than the age values established for large gold ore objects of the district: Petropavlovskoye and Novogodnee-Monto deposits (~382 million years). Taking into account the position of the Karyernoe ore occurrence on the flank of the Novogodnee ore field, it can be assumed that the disseminated and layered sulfide impregnation of the volcanic rocks of the Toupugolskaya formation could have acted as one of the sources of sulfur and ore metals for later stages of sulfide mineralization in the Toupugol-Khanmeishorsky district.

The dynamics of the phase transition (PT) in triglycine sulfate crystals, either nominally pure or doped in different ways (upon homogeneous and profiled impurity introduction into the crystal) with chrome impurity (Сr 3+ ), has been studied by analyzing the dielectric spectra measured in the ranges of frequencies 1–10 7 Hz and temperatures 23–60°C upon heating and cooling. It is shown that the introduction of impurity shifts the PT temperature range both upon heating and cooling. The PT temperature dynamics is found to depend both on the presence of impurity and on the way of its introduction into the crystal. The dependence of the width of the PT temperature range on the frequency at which the dielectric spectra were measured was shown to increase directly proportion to frequency.

The influence of a permanent magnetic field on macro- and nanoscopic properties of triglycine sulfate (TGS) crystals with impurity chromium (TGS-Cr) has been investigated. This work continues the previous studies of magnetically induced effects in ferroelectrics. A specific feature of TGS crystals is the presence of a nanoscale relief on a polar (010) cleavage; this nanorelief is a qualitative characteristic of the crystal defect structure. It is shown that the exposure of a crystal in a magnetic field of 2 T leads to a change in its dielectric properties, accompanied by a long-term transformation of the nanorelief. The results obtained are indicative of a magnetically induced change in the defect crystal structure. A qualitative difference is found between the magnetically induced effects in TGS-Cr crystals and undoped TGS crystals. The relationship between the magnetically induced effects and structural defects is discussed.

The article provides information on geological and geophysical studies of the structure of the Mid-Atlantic Ridge between the Charlie Gibbs and Maxwell transform faults in the North Atlantic during cruise 53 of the R/V Akademik Nikolaj Strakhov, July–August 2022. The preliminary results are discussed.

The results of 190 Pt– 4 He dating of placer-forming minerals of platinum (PMP) from the Baimka gold placer cluster (Western Chukotka, Russia) are reported. PMPs are represented by isoferroplatinum with a composition of Pt 3 + x Fe 1 – x and Pt 3 Fe. The concentrations of 190 Pt and 4 He in 14 PMP samples were obtained. The results of 190 Pt– 4 He dating showed the existence of two age clusters of PMP (148 ± 6 and 188 ± 4 Ma) for the first time. The primary sources of PMP, which are similar in their genetic type, but have different ages, are assumed: (1) later, 148 ± 6 Ma of the Baimka Complex (J 3 b) and (2) earlier, 188 ± 4 Ma. PMPs enter alluvial gold placers mainly from the intermediate PGM reservoir, which is composed of rocks of the Volgian stage J 3 v 2–3 (Tithonian). Thus, sedimentary rocks or explosive breccia of andesite–basalt of the Volgian stage could be the PMP source reservoir.

This paper is based on geological and geophysical data obtained during the 53th expedition of the R/V Akademik Nikolaj Strakhov. We analyze the structure of the Mid-Atlantic Ridge segment, 400 km long, in the North Atlantic (between 48° N and 51.5° N). According to our studies, this segment is characterized by specific structures formed during the formation of the oceanic crust with a reduced supply of basaltic melts. This factor leads to tectonic outcropping of deep and mantle rocks of the lower crust during the continuous extension in the rift valley. These processes, called “dry” spreading, were previously unknown in the North Atlantic.

Dependencies of the complex permittivity of chromium-doped ferroelectric triglycine sulfate crystals (TGS + Cr) have been measured using dielectric spectroscopy method in a frequency range of 1–107 Hz and a temperature range of 23–60°C upon heating and cooling. The dielectric spectra are analyzed by considering the temperature‒frequency dependences of the real (ε') and imaginary (ε") parts of permittivity in the immediate vicinity of the phase transition using the dynamic conductance model and taking into account resonance processes. Good agreement between calculated and experimental data is obtained for the dielectric response of TGS + Cr crystal near the Curie temperature.

The temperature evolution of the dielectric spectra of TGS–TGS + Cr crystals (TGS stands for triglycine sulfate) with a periodic distribution of chromium impurity (Cr3+) has been studied in comparison with nominally pure TGS crystals in the frequency range from 10 to 107 Hz upon heating and cooling. It is shown that impurity crystals are characterized by the absence of dielectric dispersion in both measurement modes. An approach is proposed to explain the peculiarities of the dielectric dispersion of crystals with a periodic distribution of chromium impurity from the standpoint of mobile activity of certain elements of the TGS crystal structure.

The investigation of the nuclear proteins has always been relevant, because they are involved in the expression, replication, storage, reparation and transmission of genetic information. It is known that sodium butyrate, as an inhibitor of protein deacetylation, leads to acetylation of histones and activates the transcriptional function of chromatin, and also it can effectively inhibit cell proliferation at low concentrations. However, it has been shown that the supplement or deletion of acetyl groups on lysine residues near the cleavage sites can regulate the sensibility of histones to proteolysis in chromatin. In the present work, the differences between 24-h seedlings of spring wheat and winter wheat in allocation of Arg-X proteolytic activity in trypsin-like complexes extracted from the fractions of non-histones and histones isolated from the nuclear structures (nucleoplasm, chromatin loosely and tightly bound and nuclear matrix) were shown. It is possible that the appearance of additional Arg-X proteolytic activity which we found in the non-histone and histone fractions that we were isolated primarily from the chromatin loosely bound and from the nuclear matrix are linked to increased histone acetylation under conditions of deacetylation inhibition of nuclear proteins. We suggest the revealed changes of Arg-X proteolysis may be associated with assembly of nucleosomes and possibly nucleosome control of gene expression.

For the first time, fatigue processes in triglycine sulfate crystals were studied using a combination of electrical and scanning probe microscopy methods. Long-term (>100 h) influence of a sinusoidal field with a frequency of 50 Hz and an amplitude of 1 kV/cm lead to a sharp decrease of the permittivity in the phase transition region and degradations of P–E hysteresis loops (a decrease of spontaneous polarization, an increase of coercive and bias fields). Changes in dielectric properties were accompanied by an increase of the defect nanoclusters density and broadening their size distribution spectrum on the (010) cleavage surface. A subsequent exposure of “fatigued” crystals in the static magnetic field of 2 T for 20 min led to hysteresis loop symmetrization, which indicates a magnetoinduced transformation in the structure of defects responsible for fatigue effects.

Temperature dynamics of the dielectric spectra and domain structure in the triglycine sulfate (TGS) hydrogen-containing ferroelectric under heating and cooling has been studied using the dielectric spectroscopy and atomic-force microscopy methods. The dielectric spectra are analyzed by the temperature-frequency dependences of the losses ε″ and by the temperature behavior of the maximum losses ε″max in the dispersion region at frequencies ranging from 102 to 106 Hz. A dynamic conductivity model is proposed for calculating temperature dependences of losses ε″max. The domain structure dynamics during the heating and cooling of the TGS crystal near the phase transition is studied using the in situ piezoresponse force microscopy. It is experimentally and theoretically shown that the relaxation dispersion is governed by the binding of strongly correlated dipoles with the main lattice that serves as a thermostat.

Впервые процессы усталости в кристаллах триглицинсульфата исследовались с использованием комбинации электрофизических методов и методов сканирующей зондовой микроскопии. Длительное (> 100 h) воздействие синусоидального поля с частотой 50 Hz и амплитудой 1 kV/cm приводило к резкому уменьшению диэлектрической проницаемости в области фазового перехода и деградации петель гистерезиса P-E (уменьшению спонтанной поляризации, увеличению коэрцитивного и смещающего полей). Изменения диэлектрических свойств сопровождались возрастанием плотности дефектных нанокластеров и расширением спектра их распределения по размерам на поверхности скола (010). Последующая выдержка "уставших" кристаллов в постоянном магнитном поле 2 T в течение 20 min приводила к симметризации петли гистерезиса, что свидетельствует о магнитоиндуцированном изменении структуры дефектов, ответственных за эффекты усталости. Работа частично поддержана Президиумом РАН (программа N I.1П). Работа выполнена с использованием оборудования ЦКП ФНИЦ "Кристаллография и фотоника" РАН при поддержке Минобрнауки. DOI: 10.21883/FTT.2017.03.44168.134

The effect of a magnetic field on the processes of relaxation of the defect structure relaxation in a triglycine sulfate (TGS) ferroelectric (nonmagnetic) crystal has been observed for the first time. The atomic-force microscopy study has shown that the application of a static weak magnetic field (2 T, 20 min) significantly changes the size distribution of defect nanoclusters characteristic of TGS. Previously known macroscopic aftereffects of the magnetic field in TGS (slow relaxation of the dielectric susceptibility, symmetrization of P–E dielectric hysteresis loops, etc.) can be explained by the redistribution of pinning centers of domain walls caused by the magnetically induced reconfiguration of the defect structure.

In higher eukaryotes, histone tails and globular domains are subjected to a variety of posttranslational modifications including regulatory proteolysis to create different chromatin structures necessary for the functioning of DNA. The aim of the present work was to detect the regions of activity of Arg-X proteolysis in complexes of histone and non-histone proteins as a potential mechanism affecting the large-scale reorganization of the chromatin. This chromatin reorganization occurs during the germination of wheat germ under conditions of highly acetylated proteins in the cell nuclei. For soaking the seeds and the induction of germination, respectively, distilled water was used as the control, and 0.004 mM sodium butyrate as the test. Cell nuclei were isolated from germs, cleared, and then the nucleoplasm, chromatin and the nuclear matrix were extracted by increasing the ionic strength of the solution. From isolated supra-molecular structures, non-histone proteins were separated from histones using ion exchange chromatography. The Arg-X proteolytic activity was assessed by cleavage of Arg-X bonds in the arginine-enriched protein protamine in all nuclear fractions. It is possible that decreasing in histone turnover due to the antiproliferative effect of the deacetylase inhibitor (sodium butyrate) is due to decreasing of proteolytic activity in histone and non-histone proteins associated with chromatin, suggesting the possible role of histone proteinases in histone metabolism. These results also enabled us to detect the regions of activity of Arg-X proteolysis in the non-histone and histone blocks. It also provided information on the specific tissues in which proteolysis activity is observed during wheat germ germination under normal conditions, as well as under conditions of highly acetylated proteins in the cell nuclei. These results provide an example of the proteinase network formed in the supra-molecular structures of cell nuclei.

The effect of a constant magnetic field on the dielectric properties of triglycine sulfate crystals has been investigated. It has been shown that, after the magnetic treatment of the crystal (2 T, 20 min), the hysteresis loop becomes narrower; i.e., the coercive field decreases, and the dielectric permittivity changes in the region of the phase transition. It has been found that the observed effect is anisotropic with respect to the orientation of the crystal in a magnetic field and occurs when the vector of magnetic induction is perpendicular to the polar axis of the crystal. The relative orientation of the magnetic field and the domain structure determines its sign. The doping of the crystal with chromium makes the effect more pronounced and leads to a change in the kinetics of the magnetically stimulated increase in the dielectric permittivity.

A hydrogen-containing ferroelectric triglycine sulfate (TGS) was comprehensively studied with an atomic force microscopy (AFM) and dielectric spectroscopy. The domain structure dynamics was in situ investigated with piezoresponse force microscopy (PFM) during heating and cooling the TGS crystal near phase transition. Relaxation dependencies of domain boundaries general perimeter and domain dimensions were obtained. TGS dielectric spectra measured at the frequency range from 10 to 10 11 Hz were analyzed on basis of significant contribution of conductivity into the dielectric response of ferroelectrics and a good agreement with the experimental data was received. It allows us to obtain more information about temperature dynamics of the domain structure.

Представлены результаты комплексного исследования водородсодержащего сегнетоэлектрика триглицинсульфата (TGS) методами атомно-силовой микроскопии (AFM) и диэлектрической спектроскопии. В режиме микроскопии пьезоэлектрического отклика (PFM) in situ изучена динамика доменной структуры при нагреве и охлаждении кристалла TGS вблизи фазового перехода. Получены релаксационные зависимости общего периметра доменных границ и размеров доменов. Измеренные в диапазоне частот от 10 до 1011 Hz диэлектрические спектры TGS проанализированы на основе представлений о заметном вкладе проводимости в диэлектрический отклик сегнетоэлектриков. Показано, что учет вклада проводимости в диэлектрические спектры дает хорошее согласие с экспериментом и позволяет получить дополнительную информацию о температурной динамике доменной структуры. Работа выполнена с использованием оборудования ЦКП ИК РАН при поддержке Министерства образования и науки.