Late Pleistocene - Holocene Volcanism on the Kamchatka Peninsula, Northwest Pacific Region

Late Pleistocene-Holocene volcanism in Kamchatka results from the subduction of the Pacific Plate under the peninsula and forms three volcanic belts arranged in en echelon manner from southeast to northwest. The cross-arc extent of recent volcanism exceeds 250 km and is one of the widest worldwide. All the belts are dominated by mafic rocks. Eruptives with SiO2>57% constitute ~25% of the most productive Central Kamchatka Depression belt and ~30% of the Eastern volcanic front, but <10% of the least productive Sredinny Range belt. All the Kamchatka volcanic rocks exhibit typical arc-type signatures and are represented by basalt-rhyolite series differing in alkalis. Typical Kamchatka arc basalts display a strong increase in LILE, LREE and HFSE from the front to the back-arc. La/Yb and Nb/Zr increase from the arc front to the back arc while B/Li and As, Sb, B, Cl and S concentrations decrease. The initial mantle source below Kamchatka ranges from N-MORB-like in the volcanic front and Central Kamchatka Depression to more enriched in the back arc. Rocks from the Central Kamchatka Depression range in 87Sr/86Sr ratios from 0.70334 to 0.70366, but have almost constant Nd isotopic ratios (143Nd/144Nd 0.51307–0.51312). This correlates with the highest U/Th ratios in these rocks and suggest the highest fluid-flux in the source region. Holocene large eruptions and eruptive histories of individual Holocene volcanoes have been studied with the help of tephrochronology and 14C dating that permits analysis of time-space patterns of volcanic activity, evolution of the erupted products, and volcanic hazards

Comparative Assessment of Prospective Protein Bases for Microbiological Media

Objective of the work is to carry out comparative assessment of the pancreatic hydrolysates of protein-containing products, both phytogenous and zoogenous, as nutrient base for microbiological media. Gelatine, soy, soy concentrate, maize gluten, fish meal, common kilka, and bovine blood have been used as a feedstock. Protein stuff hydrolysis, hydrolysate purification, and validation of physical-chemical properties were performed in accordance with conventional techniques. Testing of peptone biological parameters has been carried out on the model of nutrient agar using Shigella flexneri 1a 8516, Shigella sonnei “S form”, Pseudomonas aeruginosa 27/99, Serratia plymuthica 1 test strains. Identified have been physical-chemical parameters of the hydrolysates under study. Detected are the variations in quantity, diameter and frequency of dissociation among the colonies of Shigella flexneri 1a 8516, Shigella sonnei “S form”, chromogenesis in Pseudomonas aeruginosa 27/99, Serratia plymuthica 1, cultivated on agar media with hydrolysates under study. Obtained are the comparative data on physical-chemical and biological parameters of all experimental hydrolysates, which offers an opportunity to differentiate their choice when adding them into bacteriological nutrient media

Experimental Solid Medium for Legionella Cultivation

Presented is the principal scheme for preparation of experimental medium for Legionella cultivation on the basis of fermentative hydrolysate of pig lung. Shown is that the culture medium has good growth properties and meets the requirements of regulatory documentation for culture medium used for isolation and cultivation of the causative agent of legionellosis

Фотодинамическая терапия экспериментальных опухолей различных морфологических типов с липосомальным борированным хлорином е6

The article summarizes the results of studies of the effectiveness of photodynamic therapy using a new domestic photosensitizer liposomal borated chlorin e6 (LBC) after its parenteral administration (intraperitoneal and intravenous). Antitumor efficacy was evaluated in rats with M-1 sarcoma and PC-1 alveolar liver cancer and mice with B16 melanoma and Ehrlich’s carcinoma, which were transplanted subcutaneously into the thigh area of the animals. The aim of the study was to determine the optimal regimes of photodynamic therapy that would allow achieving the maximum antitumor effect up to 21 days after the photodynamic therapy. The therapy was carried out under the control of the accumulation of the photosensitizer in the tumor and surrounding tissues of the thigh by selecting the doses of the drug and the parameters of laser radiation (energy density and power density). The effectiveness of therapy was assessed by the inhibition of tumor growth, by the percentage of animals with complete tumor regression, by the absolute growth rate in animals with continued tumor growth compared to controls. The results of our studies have shown that the domestic photosensitizer liposomal borated chlorin e6 has high antitumor activity in vivo. In an experimental study of the photosensitizer under certain PDT modes, the maximum antitumor effect (complete tumor regression in 100% of animals) was obtained up to 21 days after PDT in all tumor models used.Обобщены результаты исследований эффективности фотодинамической терапии (ФДТ) с использованием нового отечественного фотосенсибилизатора липосомального борированного хлорина е6 после его парентерального введения (внутрибрюшинное и внутривенное). Противоопухолевую эффективность препарата оценивали на моделях перевивных опухолей: саркома М–1 и альвеолярный рак печени РС–1 у крыс, меланома В16 и карцинома Эрлиха у мышей. Опухоли перевивали подкожно в область бедра животных. Цель исследования состояла в определении оптимальных режимов ФДТ, позволяющих добиться максимального противоопухолевого эффекта до 21 сут после проведения ФДТ. Терапию проводили под контролем накопления фотосенсибилизатора в опухолевой и окружающих тканях бедра, осуществляя подбор доз препарата и параметров лазерного излучения (плотность энергии и плотность мощности). Эффективность терапии оценивали по следующим параметрам: торможение роста опухоли, процент животных с полной регрессией опухоли, коэффициент абсолютного прироста опухоли у животных с продолженным ростом. Результаты исследований показали, что отечественный фотосенсибилизатор липосомальный борированный хлорин е6 обладает высокой противоопухолевой активностью in vivo. При экспериментальном исследовании фотосенсибилизатора при определенных режимах ФДТ получен максимальный противоопухолевый эффект (полная регрессия опухоли у 100% животных) до 21 сут после проведения ФДТ на всех использованных опухолевых моделях

Observation of fluctuation-mediated picosecond nucleation of a topological phase

peer reviewedTopological states of matter exhibit fascinating physics combined with an intrinsic stability. A key challenge is the fast creation of topological phases, which requires massive reorientation of charge or spin degrees of freedom. Here we report the picosecond emergence of an extended topological phase that comprises many magnetic skyrmions. The nucleation of this phase, followed in real time via single-shot soft X-ray scattering after infrared laser excitation, is mediated by a transient topological fluctuation state. This state is enabled by the presence of a time-reversal symmetry-breaking perpendicular magnetic field and exists for less than 300 ps. Atomistic simulations indicate that the fluctuation state largely reduces the topological energy barrier and thereby enables the observed rapid and homogeneous nucleation of the skyrmion phase. These observations provide fundamental insights into the nature of topological phase transitions, and suggest a path towards ultrafast topological switching in a wide variety of materials through intermediate fluctuating states. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.Leibniz Association Grant no. K162/2018 (OptiSPIN

Mantle and fluid sources below Klyuchevskoy-Kamen-Bezymianny line (Kamchatka)

Kamen volcano is an extinct volcanic complex located in the central part of the Klyuchevskaya group of volcanoes (KGV) between active Klyuchevskoy, Bezymianny, and Ploskie Sopky volcanoes. Kamen volcano was mapped by V.A. Ermakov only in the 1970s. However the modern geochemical studies of Kamen volcano have not been previously carried out and its relationship and petrogenesis in comparison to other active neighbors are unknown. A modern geochemical study of Kamen volcano is needed because it will shed light not only on the history of the volcano itself and its closest neighbors, but also on the history and magmatic evolution of the KGV melts in general. The distance between the summits of Kamen and Klyuchevskoy is only 5 km, the same as between Kamen and Bezymianny. The close relationship in space and time of the KGV and the common zone of seismicity below them suggests a common source and a possible genetic relationship between their magmas. However, the Late-Pleistocene-Holocene lavas of all these neighboring volcanoes are very different: high-Mg and high-Al Ol-Cpx-Pl basalts and basaltic andesites occur at Klyuchevskoy volcano, and Hbl-bearing andesites and dаcites dominate at Bezymianny volcano. The rocks of Ploskie Sopky volcano, situated only 10 km NW of Kamen, are represented by medium-high-K subalkaline lavas

Sources and Fluids in the Mantle Wedge below Kamchatka, Evidence from Across-arc Geochemical Variation

Major and trace element and Sr–Nd–Pb isotopic variations in mafic volcanic rocks hve been studied in a 220 km transect across the Kamchatka arc from the Eastern Volcanic Front, over the Central Kamchatka Depression to the Sredinny Ridge in the back-arc. Thirteen volcanoes and lava fields, from 110 to 400 km above the subducted slab, were sampled. This allows us to characterize spatial variations and the relative amount and composition of the slab fluid involved in magma genesis. Typical Kamchatka arc basalts, normalized for fractionation to 6% MgO, display a strong increase in large ion lithophile, light rare earth and high field strength elements from the arc front to the back-arc. Ba/Zr and Ce/Pb ratios, however, are nearly constant across the arc, which suggests a similar fluid input for Ba and Pb. La/Yb and Nb/Zr increase from the arc front to the back-arc. Rocks from the Central Kamchatka Depression range in 87Sr/86Sr from 0·70334 to 0·70366, but have almost constant Nd isotopic compositions (143Nd/144Nd 0·51307–0·51312). This correlates with the highest U/Th ratios in these rocks. Pb-isotopic ratios are mid-ocean ridge basalt (MORB)-like but decrease slightly from the volcanic front to the back-arc. The initial mantle source ranged from N-MORB-like in the volcanic front and Central Kamchatka Depression to more enriched in the back-arc. This enriched component is similar to an ocean-island basalt (OIB) source. Variations in (CaO)6·0–(Na2O)6·0 show that degree of melting decreases from the arc front to the Central Kamchatka Depression and remains constant from there to the Sredinny Ridge. Calculated fluid compositions have a similar trace element pattern across the arc, although minor differences are implied. A model is presented that quantifies the various mantle components (variably depleted N-MORB-mantle and enriched OIB-mantle) and the fluid compositions added to this mantle wedge. The amount of fluid added ranges from 0·7 to 2·1%. The degree of melting changes from ∼20% at the arc front to <10% below the back-arc region. The rocks from volcanoes of the northern part of the Central Kamchatka Depression—to the north of the transect considered in this study—are significantly different in their trace element compositions compared with the other rocks of the transect and their source appears to have been enriched by a component derived from melting of the edge of the ruptured slab