Lidar and satellite temperature measurements during the sudden stratospheric warmings over Siberia and the Russian Far East in 2008–2012

This article presents a comprehensive study of disturbances of the temperature regime of the Earth’s stratosphere, which are related to sudden stratospheric warmings over Western and Eastern Siberia and the Russian Far East in the winters of 2008–2012. This study is based on data obtained using temperature remote-sensing techniques (lidar and satellite ones). The analysis rests on data on vertical temperature distribution in the stratosphere, obtained from lidar measurements over regions of Tomsk (56°N, 85°E), Yakutsk (61°N, 130°E), and Paratunka, the Kamchatka territory (53°N, 158°E). For complex analysis of the spatial–temporal temperature distribution in the middle atmosphere, the lidar measurement data are applied along with satellite data on temperature acquired by the microwave limb sounder on the Earth Observing System Aura satellite. We consider the regional effects of sudden stratospheric warmings that were observed over the Asian region of Russia (~85–160°E) in the winters of 2008–2012. There were stratospheric warmings over the Asian region of Russia each winter during the period under consideration, as deduced from lidar and satellite measurements of temperature. Lidar and satellite measurements of temperature have evidenced the previously known peculiarities of the development of winter stratospheric warmings. On the whole, lidar and satellite measurements of height distribution of temperatures agree. Possible reasons for the divergences under consideration are discussed.     

The Influence of a Flow of Low-Temperature Nitrogen Plasma on the Morphology,Electric Properties,and UV Photoconductivity of ZnO Films on Sapphire

Technical Physics Letters - We have studied the influence of a flow of high-enthalpy nitrogen plasma generated by a dc plasmatron on the morphology, electrical properties, and UV photoconductivity...     

High-temperature phase-transition heat-accumulating materials based on the Li,Na, Ca,Ba‖F,MoO4 system and their properties

The issues of the physical and chemical analysis of multicomponent systems (MCSs) are considered with the aim to find phase-transition heat-accumulating materials (PHAMs). New salt compositions of eutectic proportions formed by molybdates and fluorides of alkali (Li and Na) and alkaline earth (Ca and Ba) metals, obtained experimentally, are proposed as PHAMs. Their heat of fusion and heat capacity are determined.     

A Palladium Based Alloy for Prosthetic Dentistry: Structure and Properties

Using the results of physical and chemical researches and mechanical tests of the Pd-Au-Cu-Sn system alloys, a new palladium-based alloy has been chosen and studied in detail. It has a higher plasticity and a lower hardness than the Palladent alloy, widely used in prosthetic dentistry: its hardness is lower than 300 MPa, and its specific elongation is 10%~14 %. At the same time, such important practical characteristics of the alloys as the strength of adhesion to ceramics and thermal expansion coefficient are almost similar.     

Synthesis of various carbon modifications during thermolysis of poly(hydrocarbyne)

The conditions of poly(hydrocarbyne) transformations into various carbon modifications have been studied. The activation of the rearrangement of the material carbon skeleton by metal potassium is shown to give rise to potassium hydride and carbyne. In thermolysis at high pressures (3.0–8.0 GPa) and temperatures (900–1500°C), submicron diamonds and fcc carbon, which form together with graphite and glassy carbon, have been obtained.     

Segmenting and tracking fluorescent cells in dynamic 3-D microscopy with coupled active surfaces.

Cell migrations and deformations play essential roles in biological processes, such as parasite invasion, immune response, embryonic development, and cancer. We describe a fully automatic segmentation and tracking method designed to enable quantitative analyses of cellular shape and motion from dynamic three-dimensional microscopy data. The method uses multiple active surfaces with or without edges, coupled by a penalty for overlaps, and a volume conservation constraint that improves outlining of cell/cell boundaries. Its main advantages are robustness to low signal-to-noise ratios and the ability to handle multiple cells that may touch, divide, enter, or leave the observation volume. We give quantitative validation results based on synthetic images and show two examples of applications to real biological data.     

Specific Features of Temperature Dependence of Graphene Oxide Resistance

Protection of Metals and Physical Chemistry of Surfaces - Temperature dependence of graphene oxide resistance during continuous heating and cooling under argon atmosphere at 300–550 K and...     

Evolutionary Origins of the Photosynthetic Water Oxidation Cluster: Bicarbonate Permits Mn2+ Photo‐oxidation by Anoxygenic Bacterial Reaction Centers

The enzyme that catalyzes water oxidation in oxygenic photosynthesis contains an inorganic cluster (Mn₄CaO₅) that is universally conserved in all photosystem II (PSII) protein complexes. Its hypothesized precursor is an anoxygenic photobacterium containing a type 2 reaction center as photo‐oxidant (bRC2, iron–quinone type). Here we provide the first experimental evidence that a native bRC2 complex can catalyze the photo‐oxidation of Mn²⁺ to Mn³⁺, but only in the presence of bicarbonate concentrations that allows the formation of (bRC2)Mn²⁺(bicarbonate)_1–2 complexes. Parallel‐mode EPR spectroscopy was used to characterize the photoproduct, (bRC2)Mn³⁺(CO₃^2?), based on the g tensor and ⁵⁵Mn hyperfine splitting. (Bi)carbonate coordination extends the lifetime of the Mn³⁺ photoproduct by slowing charge recombination. Prior electrochemical measurements show that carbonate complexation thermodynamically stabilizes the Mn³⁺ product by 0.9–1 V relative to water ligands. A model for the origin of the water oxidation catalyst is presented that proposes chemically feasible steps in the evolution of oxygenic PSIIs, and is supported by literature results on the photoassembly of contemporary PSIIs.     

Growth and Potential Damage of Human Bone-Derived Cells on Fresh and Aged Fullerene C60 Films

Fullerenes are nanoparticles composed of carbon atoms arranged in a spherical hollow cage-like structure. Numerous studies have evaluated the therapeutic potential of fullerene derivates against oxidative stress-associated conditions, including the prevention or treatment of arthritis. On the other hand, fullerenes are not only able to quench, but also to generate harmful reactive oxygen species. The reactivity of fullerenes may change in time due to the oxidation and polymerization of fullerenes in an air atmosphere. In this study, we therefore tested the dependence between the age of fullerene films (from one week to one year) and the proliferation, viability and metabolic activity of human osteosarcoma cells (lines MG-63 and U-2 OS). We also monitored potential membrane and DNA damage and morphological changes of the cells. After seven days of cultivation, we did not observe any cytotoxic morphological changes, such as enlarged cells or cytosolic vacuole formation. Furthermore, there was no increased level of DNA damage. The increasing age of the fullerene films did not cause enhancement of cytotoxicity. On the contrary, it resulted in an improvement in the properties of these materials, which are more suitable for cell cultivation. Therefore, fullerene films could be considered as a promising material with potential use as a bioactive coating of cell carriers for bone tissue engineering.