The problem of the genesis of the Mesoarchean aluminosilicate rocks from the Karelian craton and their possible use as a quartz-feldspar raw material

The article presents original data obtained in the study of the chemical and mineral compositions of the Late Archean aluminosilicate rocks (formerly called silicites) from the Koikari and Elmus structures of the Vedlozero-Segozero greenstone belt of the Karelian craton (Central Karelia). A comprehensive study of these formations revealed their complex genesis as a result of the late imposition of hydrothermal and metamorphic alteration on sedimentary and volcanic-sedimentary rocks of feldspar-quartz composition. Due to the superimposed metasomatic (temperature?) impact on feldspar-quartz siltstones, Fe was removed from microinclusions in quartz and feldspar and its oxides were concentrated along the grain boundaries. Minerals such as monazite, parisite, allanite are also located either along the grain boundaries of quartz and feldspars, or together with calcite they fill microfractures, which makes it possible to get rid of them when preparing quartz-feldspar concentrates using various beneficiation technologies. According to most indicators limited by GOSTs, individual samples in their natural form meet the requirements for quartz-feldspar raw materials for use as part of batch in the production of diverse types of glass. Additional beneficiation of the feedstock (grinding, screening into narrow classes and further magnetic separation) leads to a decrease in Fe2O3 content to normalized values. The resulting quartz-feldspar concentrates with various particle sizes can be used in the production of building material and fine ceramics (sanitary and ceramic products, facing and finishing tiles, artistic, household porcelain and faience). The homogeneity of the mineral and chemical composition, the possibility of compact extraction and beneficiation (including in mobile small-sized installations) increase the prospects and competitiveness of this non-traditional feldspar raw material from Central Karelia

Composition and physico-chemical properties of aqueous extracts of lydites of the North Onega synclinorium in Karelia

Relevance. The need to obtain reliable information on chemical composition of aqueous extracts of lydites. There is lack of such information, but it is so important both for understanding dispersion of elements and their impact on natural waters of a region. It is necessary to study the composition of aqueous extracts as a result of water–rock interaction to determine possible sources of water pollution with toxic elements. Mineral composition of lydites of the North Onega synclinorium contains organic carbon and mist pyrite, which may contain increased concentrations of trace elements "harmful" for drinking water. To determine the ability of such elements to pass into a dissolved state, it is necessary to study aqueous extracts of lydites. Aim. To determine trace element composition and physico-chemical properties of aqueous extracts of lydites selected from two districts of the North Onega synclinorium to assess their environmental hazard. Objects. Geological section of the shungite-lidite-dolomite complex of the Zaonezhskaya formation of the Paleoproterozoic age of the North Onega synclinorium. Samples of lidites were taken at the Tetyugino (LT) and Shunga (LSh) sites of the Medvezhyegorsk district of the Republic of Karelia. Methods. Field studies, including investigation of stratigraphic position of lydites in geological sections of the Tetyugino and Shunga sites and sampling, laboratory experiment, aqueous extraction, scanning electron microscopy, Raman spectroscopy, X-ray fluorescence analysis, Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results. Mineralogical composition of the lydites of both sites is similar. Taking into account high content of SiO2 and negligible content of other petrogenic oxides in chemical composition of lydites, it is possible to consider them as a source for obtaining pure quartz raw materials. The structure of lydites is clot-cryptocrystalline and clot-globular. Lydite extracts environment acidity depends on the totality of the minerals extracted from it, either basic (dolomite) or acidic (pyrite oxidation products). This factor is decisive in formation of chemical composition of lydite extracts, regardless of the location of the samples within a given geological object. Many elements extracted by water from the lydite samples of two regions under consideration are characterized by varying degrees of their extraction from the massive and veined parts of the sample. The cure coefficients of chemical elements in the form of the ratio of element average concentrations in the extract and lydite solid phase show the predominant intake of Cd, Mn, Mo, Sr, Rb, Li, Ni, Co, Li from Tetyugino lydites into water. Mo, Sb and W are predominantly extracted into the solution from the Shunga lydites. Average concentrations of most elements of the extracts of the Shunga samples satisfy the requirements for drinking water and, unlike shungite, they are not sources of harmful components in water. Therefore, it is advisable to carry out work on the possibility of their use for water purification for drinking purposes

Doxorubicin pharmacokinetics in lymphoma patients treated with doxorubicin-loaded eythrocytes

Doxorubicin-loaded erythrocytes (DLE) were administrated to 15 lymphoma patients. Antibiotic peak concentration in blood decreased by 55%, doxorubicin circulated several times longer, and the area under the concentration-time curve increased 5 times if compared with standard doxorubicin administration. The DLE was well tolerated by patients

Pure Gauge Configurations and Tachyon Solutions to String Field Theories Equations of Motion

In constructions of analytical solutions to open string field theories pure gauge configurations parameterized by wedge states play an essential role. These pure gauge configurations are constructed as perturbation expansions and to guaranty that these configurations are asymptotical solutions to equations of motions one needs to study convergence of the perturbation expansions. We demonstrate that for the large parameter of the perturbation expansion these pure gauge truncated configurations give divergent contributions to the equation of motion on the subspace of the wedge states. We perform this demonstration numerically for the pure gauge configurations related to tachyon solutions for the bosonic and the NS fermionic SFT. By the numerical calculations we also show that the perturbation expansions are cured by adding extra terms. These terms are nothing but the terms necessary to make valued the Sen conjectures.Comment: 30 pages, 9 figures, references added and conclusion extende

A community effort in SARS-CoV-2 drug discovery.

peer reviewedThe COVID-19 pandemic continues to pose a substantial threat to human lives and is likely to do so for years to come. Despite the availability of vaccines, searching for efficient small-molecule drugs that are widely available, including in low- and middle-income countries, is an ongoing challenge. In this work, we report the results of an open science community effort, the "Billion molecules against Covid-19 challenge", to identify small-molecule inhibitors against SARS-CoV-2 or relevant human receptors. Participating teams used a wide variety of computational methods to screen a minimum of 1 billion virtual molecules against 6 protein targets. Overall, 31 teams participated, and they suggested a total of 639,024 molecules, which were subsequently ranked to find 'consensus compounds'. The organizing team coordinated with various contract research organizations (CROs) and collaborating institutions to synthesize and test 878 compounds for biological activity against proteases (Nsp5, Nsp3, TMPRSS2), nucleocapsid N, RdRP (only the Nsp12 domain), and (alpha) spike protein S. Overall, 27 compounds with weak inhibition/binding were experimentally identified by binding-, cleavage-, and/or viral suppression assays and are presented here. Open science approaches such as the one presented here contribute to the knowledge base of future drug discovery efforts in finding better SARS-CoV-2 treatments.R-AGR-3826 - COVID19-14715687-CovScreen (01/06/2020 - 31/01/2021) - GLAAB Enric

Operando Photo-Electrochemical Catalysts Synchrotron Studies

The attempts to develop efficient methods of solar energy conversion into chemical fuel are ongoing amid climate changes associated with global warming. Photo-electrocatalytic (PEC) water splitting and CO2 reduction reactions show high potential to tackle this challenge. However, the development of economically feasible solutions of PEC solar energy conversion requires novel efficient and stable earth-abundant nanostructured materials. The latter are hardly available without detailed understanding of the local atomic and electronic structure dynamics and mechanisms of the processes occurring during chemical reactions on the catalyst–electrolyte interface. This review considers recent efforts to study photo-electrocatalytic reactions using in situ and operando synchrotron spectroscopies. Particular attention is paid to the operando reaction mechanisms, which were established using X-ray Absorption (XAS) and X-ray Photoelectron (XPS) Spectroscopies. Operando cells that are needed to perform such experiments on synchrotron are covered. Classical and modern theoretical approaches to extract structural information from X-ray Absorption Near-Edge Structure (XANES) spectra are discussed

Crystal structures of di-μ-bromido-bis{dibromido[η5-2-(dimethylamino)indenyl]zirconium(IV)} and dibromidobis[η5-2-(dimethylamino)indenyl]zirconium(IV)

In the title compounds, [Zr2Br6(C11H12N)2], (I) and [ZrBr2(C11H12N)2], (II), the positions of the η5-binding 2-dimethylaminoindenyl units are fixed by intramolecular C—H...Br interactions involving aromatic or dimethylamino H atoms. The binuclear molecule of (I) is located on a general position, while the mononuclear molecule of (II) is situated on a twofold rotation axis. Both ZrIV atoms in (I) are ligated by one cyclopentadienyl (CP) ring and four Br ligands (two bridging, two terminal), while in (II) the ZrIV atom is ligated by two CP rings and two terminal Br ligands. The crystal structures of both (I) and (II) comprise of strands of π–π- and N–π-bonded molecules, which in turn are linked by C—H...Br interactions

Photoluminescence and Energy Transfer in Double- and Triple-Lanthanide-Doped YVO4 Nanoparticles

Optical materials doped with several lanthanides are unique in their properties and are widely used in various fields of science and technology. The study of these systems provides solutions for noncontact thermometry, bioimaging, sensing technology, and others. In this paper, we report on the demonstration of YVO4 nanoparticles doped with one, two, and three different rare earth ions (Tm3+, Er3+, and Nd3+). We discuss the morphology, structural properties, and luminescence behavior of particles. Luminescence decay kinetics reveal the energy transfer efficiency (up to 78%) for different ions under the selective excitation of individual ions. Thus, we found that the energy transition from Tm3+ is more favorable than from Er3+ while we did not observe any significant energy rearrangement in the samples under the excitation of Nd3+. The observed strong variation of REI lifetimes makes the suggested nanoparticles promising for luminescent labeling, anticounterfeiting, development of data storage systems, etc