The article is devoted to the study of the content of heavy metals in the bottom sediments of the estuary of the Pechora River, which is the largest river in the European Arctic of Russia. In ...addition to metals, the particle size distribution and physicochemical parameters of river sediments were analyzed, such as the content of carbonates, organics and ash components. Average concentrations of heavy metals in the sediments of the Pechora Delta sediment have been found to be significantly lower than terrestrial values. The assessment of pollution and toxicity of sediments in the Pechora delta, made using various parameters Igeo, Cf, Cd, EF and ERI, showed a low level of heavy metals in bottom sediments, coupled with a low level of environmental risk. Despite the fact that high concentrations of heavy metals of anthropogenic origin are continuously recorded in the water of the Pechora River, (almost throughout the entire length), there is no accumulation of pollutants in the sediments of the delta. Thus, the estuary of the Pechora River, unlike other large estuary systems, does not act as a filter or sediment trap, which contributes to the penetration of heavy metals deep into the Barents Sea and the widespread distribution of pollutants in the ecosystems of the Arctic.
•Heavy metal concentrations in bottom sediments of the Pechora River estuary were analyzed.•Geochemical data indicate enrichment of the estuary sediments in Si and Ba.•All heavy metals showed a low ecological risk indexes.•Sediments of the Pechora River estuary weakly accumulate pollutants entering the river water.
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•First obtain zero-thermal-quenching Mn4+-activated phosphor in perovskite structure.•A high efficiency (IQE: 89.3%) far-red-emitting phosphor is synthesized.•Quantificationally ...evaluate the spectrum resemblance between obtained phosphor and phytochrome.•Show a very good application prospect for improving plant photosynthesis.
Nowadays, Mn4+-doped oxide phosphors have attracted more and more attentions owing to their widespread applications in white LEDs, optical data storage and agricultural production, but these phosphors have two most significant problems including thermal quenching (TQ) and low quantum efficiency. Here, we report a far-red-emitting LaAlO3:3%Ca2+,1%Bi3+,0.1%Mn4+ perovskite phosphor which exhibits zero-TQ even up to 150 °C and high internal quantum efficiency (IQE) of 89.3%. To our best knowledge, the zero-TQ phenomenon is first realized in Mn4+-activated perovskite phosphors caused by the synergistic action of Ca2+ and Bi3+ which is attributed to the efficient energy transfer, energy compensation and structural rigidity enhancement. Moreover, the gratifying luminous performance improvement is obtained due to charge compensation effect, optimized crystal field and excited electrons transfer. The main emission peak of this phosphor is monitored at ~730 nm which perfectly matches the absorption spectrum of phytochrome PFR which has a good application prospect for improving plant seed germination, flowering, fruiting and aging. These findings may provide a feasible way to simultaneously improve thermal stability and quantum efficiency of Mn4+ luminescence in oxide hosts.
The future of adaptive materials will rely on transduction of molecular motion across increasing length scales, up to the macroscopic and functional level. In this context, liquid crystals have ...emerged as a promising amplification medium, in view of their long-range order and high sensitivity to external stimuli, and in particular, chiral liquid crystals have demonstrated widely tunable optical properties and invertible handedness. Here, we demonstrate that by applying weak electric fields, regular, periodic and light-tunable patterns can be formed spontaneously in cholesteric liquid crystals. These patterns can be used as light-tunable diffraction gratings for which the period, the diffraction efficiency, and the in-plane orientation of grating vector can be controlled precisely, reversibly, and independently. Such a photoregulation allows generating a variety of one- and two-dimensional complex diffractive patterns in a single material. Our data are also supported by modeling and theoretical calculations. Overall, the fine tunability of cholesteric materials doped with artificial molecular switches makes them attractive for optics and photonics.
The article analyzes the changes in the regulatory and legal framework related to the development of the main document on oil spill response planning. the key points of the regulatory and ...methodological framework applied until January 1, 2021, which should have been given special attention, are highlighted. The second part of the article analyzes the updated regulatory and legal framework for preventing and responding to spills. the third part provides a comparative analysis of the old and new legislation governing the development of oil and petroleum product spill prevention and response plan, and also discusses some methodological aspects. The results of the analysis are formulated in the conclusion. It is noted that despite innovations, scientific and methodological support of development remains insufficient.
Molecular, morphological, and physiological heterogeneity is the inherent property of cells which governs differences in their response to external influence. Tumor cell metabolic heterogeneity is of ...a special interest due to its clinical relevance to tumor progression and therapeutic outcomes. Rapid, sensitive, and noninvasive assessment of metabolic heterogeneity of cells is a great demand for biomedical sciences. Fluorescence lifetime imaging (FLIM), which is an all-optical technique, is an emerging tool for sensing and quantifying cellular metabolism by measuring fluorescence decay parameters of endogenous fluorophores, such as NAD(P)H. To achieve accurate discrimination between metabolically diverse cellular subpopulations, appropriate approaches to FLIM data collection and analysis are needed. In this paper, the unique capability of FLIM to attain the overarching goal of discriminating metabolic heterogeneity is demonstrated. This has been achieved using an approach to data analysis based on the nonparametric analysis, which revealed a much better sensitivity to the presence of metabolically distinct subpopulations compared to more traditional approaches of FLIM measurements and analysis. The approach was further validated for imaging cultured cancer cells treated with chemotherapy. These results pave the way for accurate detection and quantification of cellular metabolic heterogeneity using FLIM, which will be valuable for assessing therapeutic vulnerabilities and predicting clinical outcomes.
Two-dimensional (2D) topological insulator is a promising quantum phase for achieving dissipationless transport due to the robustness of the gapless edge states resided in the insulating gap ...providing realization of the quantum spin Hall effect. Searching for two-dimensional realistic materials that are able to provide the quantum spin Hall effect and possessing the feasibility of their experimental preparation is a growing field. Here we report on the two-dimensional (In, Sb)2 3 × 2 3 compound synthesized on Si(111) substrate and its comprehensive experimental and theoretical investigations based on an atomic-scale characterization by using scanning tunneling microscopy and angle-resolved photoelectron spectroscopy as well as ab initio density functional theory calculations identifying the synthesized 2D compound as a suitable system for realization of the quantum spin Hall effect without additional functionalization like chemical adsorption, applying strain, or gating.
In recent decades, many new flavi-like viruses have been discovered predominantly in different invertebrates and, as was recently shown, some of them may cause disease in humans. The Jingmenvirus ...(JMV) group holds a special place among flaviviruses and flavi-like viruses because they have a segmented ssRNA(+) genome. We detected Alongshan virus (ALSV), which is a representative of the JMV group, in ten pools of adult
ticks collected in two geographically-separated Russian regions. Three of the ten strains were isolated in the tick cell line IRE/CTVM19. One of the strains persisted in the IRE/CTVM19 cells without cytopathic effect for three years. Most ALSV virions purified from tick cells were spherical with a diameter of approximately 40.5 nm. In addition, we found smaller particles of approximately 13.1 nm in diameter. We obtained full genome sequences of all four segments of two of the isolated ALSV strains, and partial sequences of one segment from the third strain. Phylogenetic analysis on genome segment 2 of the JMV group clustered our novel strains with other ALSV strains. We found evidence for the existence of a novel upstream open reading frame in the glycoprotein-coding segment of ALSV and other members of the JMV group.
Ho2O3 transparent ceramics were fabricated by vacuum pre-sintering combined with hot isostatic pressing (HIP) post-treatment at relatively low temperature from high-purity Ho2O3 powder calcined at ...1000 °C for 4 h. The optimal Ho2O3 ceramic sample prepared by vacuum pre-sintering at 1250 °C and HIP post-treating at 1450 °C has a dense microstructure with average grain size of 0.77 μm, and the in-line transmittances reach 80.7 % at 1550 nm and 76.7 % at 1064 nm. The effect of air annealing on the optical quality of Ho2O3 ceramics was studied, and the existence of compressed pores in the HIP-ed Ho2O3 ceramics was confirmed. The Verdet constants of Ho2O3 ceramics were measured to be -47.4 rad/(T m at 1064 nm and -15.4 rad/(T m at 1561 nm. High transmittance and large Verdet constant in the wavelength regions 1–1.07 μm, 1.3–1.5 μm make Ho2O3 transparent ceramics promising for magneto-optical devices for lasers based on Yb-, Nd-doped materials and telecom lasers.
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