74 research outputs found
Lipid Composition Modifications in the Blue Mussels (Mytilus edulis L.) from the White Sea
Studying biochemical indicators in response to various environmental factors allows revealing the metabolic adaptive strategy of the organism’s tolerance and survival under a variety of environmental impacts. This review analyses both the authors’ own data and the available literature on the problem of biochemical adaptations of the lipid composition in marine bivalves, particularly blue mussels, Mytilus edulis L., to various environmental impacts. Modifications in the composition of lipids and their fatty acids in blue mussels caused by short-term (under laboratory conditions) and chronic (field monitoring) exposure to natural and human factors indicate that homeostasis is maintained in cell membranes and the organism’s energy requirements and facilitate the adaptation and tolerance of the mussels to environmental disturbances. The lipid and fatty acid composition indices in White Sea intertidal mussels which reflect their chronic exposure to a wide variety of environmental factors are discussed and compared to data on changes in the lipid composition of blue mussels exposed to some environmental factors (salinity, anoxia, metals) in aquarium experiments. The lipid profile plays an important role in the adaptation of blue mussels to new conditions in the habitat, and it can be used as a biochemical marker for indicating the organism’s physiological state
School transition to the state-social management system based on the project approach application
The paper looks at the opportunities for the school transition to the state-social management system based on the project approach application. The principle methods and procedures for the project initiation are observed along with the project organization and planning, recourse provision and project monitoring. According to the author, the most effective form of initiating the management modernization project simultaneously involves the two participants: the internal (school management) and external (educational management organizations), provided that the external one sets the main requirements. Using the project approach allows the fast knowledge accumulation for further application. In this regard, it is more efficient than the program-targeted management requiring more time and effort for fulfilling the program. In author’s opinion, the project method can be extended to solving the problem situations. For example, its application is the most expedient in step-by-step implementation of the state-social management, given that not every school can restructure the existing management system by itself В статье представлены возможности перехода школ к государственно-общественному управлению на основе использования проектного подхода. Подробно рассмотрены основные методы и процедуры инициации проекта, организации и планирования проектных работ, их ресурсного обеспечения и мониторинга реализации проекта. Доказано, что наиболее эффективна форма, при которой инициация проекта модернизации управления осуществляется одновременно двумя субъектами: внутренним (руководством школы) и внешним (органами управления образованием), при условии, что внешний субъект задает основные требования. Использование проектного подхода позволяет достаточно быстро накопить знания, которые могут быть применены в последующем. В этом отношении он более эффективен, чем программно-целевое управление, при котором для выполнения программ требуется значительно больше времени и усилий. По мнению автора статьи, проектный метод работы следует распространять на решение новых проблемных ситуаций. Применение проектного подхода наиболее целесообразно, например, при поэтапном введении государственно-общественного управления, когда далеко не каждая школа готова самостоятельно перестраивать сложившуюся систему управлени
Mathematical Computing of Coniferous Tree Ignition by the Cloud-to-Ground Lightning Discharge using Joule-Lenz's Law
The natural phenomenon of thunderstorm activity is one of many causes of a forest fire. Thunderstorms cause especially intensive fire danger situations within remote areas and highlands. As a rule, a cloud-to-ground lightning discharge is the fire source. The present study is based on the research results of electrical overloads in supply networks. Physical and mathematical formulation and numerical solution for the problem of a coniferous tree (pine) ignited by a cloud-to-ground lightning discharge are presented. The problem is considered in a cylindrical coordinate system in two-dimensional formulation. The features of current passage and heat transfer taking into account the reactive wood localization are investigated. The Joule-Lenz’s law is used to calculate heat production in a tree trunk. Parametric analysis has been conducted and tree trunk ignition conditions have been determined in a typical range for the influencing parameters of negative and positive discharges
Numerical modeling of the evaporation process of unsymmetric dimethylhydrazine drops in the Earth's atmosphere
The evaporation process of unsymmetric dimethylhydrazine drops at their movement to the Earth's surface after seal failure of fuel tanks of launch rockets at heights up to 50 km has been simulated
Into the deep: New data on the lipid and fatty acid profile of redfish Sebastes mentella inhabiting different depths in the Irminger Sea
New data on lipid and fatty acid profiles are presented, and the dynamics of the studied components in muscles in the males and females of the beaked redfish, Sebastes mentella, in the depth gradient of the Irminger Sea (North Atlantic) is discussed. The contents of the total lipids (TLs), total phospholipids (PLs), monoacylglycerols (MAGs), diacylglycerols (DAGs), triacylglycerols (TAGs), cholesterol (Chol), Chol esters, non-esterified fatty acids (NEFAs), and wax esters were determined by HPTLC; the phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), and lysophosphatidylcholine (LPC) were determined by HPLC; and fatty acids of total lipids were determined using GC. The Chol esters prevailed in muscles over the storage TAGs, and the wax ester content was high, which is a characteristic trait of vertically migrating species. Specific dynamics in certain PL in redfish were found to be depended on depth, suggesting that PLs are involved in the re-arrangement of the membrane physicochemical state and the maintenance of motor activity under high hydrostatic pressure. The high contents of DHA and EPA were observed in beaked redfish muscles is the species’ characteristic trait. The MUFAs in muscles include dietary markers of zooplankton (copepods)—20:1(n-9) and 22:1(n-11), whose content was found to be lower in fish sampled from greater depth
A new technique for laser cooling with superradiance
We present a new theoretical scheme for laser cooling of rare earth doped
solids with optical super-radiance (SR), which is the coherent, sharply
directed spontaneous emission of photons by a system of laser excited rare
earth ions in the solid state host (glass or crystal). We consider an Yb3+
doped ZBLAN sample pumped at the wavelength 1015 nm with a rectangular pulsed
source with a power of ~433W and duration of 10ns. The intensity of the SR is
proportional to the square of the number of excited ions. This unique feature
of SR permits a dramatic increase in the rate of the cooling process in
comparison with the traditional laser cooling of the rare earth doped solids
with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme
overcomes the limitation of using only low phonon energy hosts for laser
cooling.Comment: 10 pages,6 figure
Cellular effects of terahertz waves
Significance: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied. Aim: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves. Approach: We start with a brief overview of general features of the THz-wave–tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules;(ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave–cell interactions and discuss a problem of adequate estimation of the THz biological effects’ specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered. Results: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects. Conclusions: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications
Dynamically-Driven Inactivation of the Catalytic Machinery of the SARS 3C-Like Protease by the N214A Mutation on the Extra Domain
Despite utilizing the same chymotrypsin fold to host the catalytic machinery, coronavirus 3C-like proteases (3CLpro) noticeably differ from picornavirus 3C proteases in acquiring an extra helical domain in evolution. Previously, the extra domain was demonstrated to regulate the catalysis of the SARS-CoV 3CLpro by controlling its dimerization. Here, we studied N214A, another mutant with only a doubled dissociation constant but significantly abolished activity. Unexpectedly, N214A still adopts the dimeric structure almost identical to that of the wild-type (WT) enzyme. Thus, we conducted 30-ns molecular dynamics (MD) simulations for N214A, WT, and R298A which we previously characterized to be a monomer with the collapsed catalytic machinery. Remarkably, three proteases display distinctive dynamical behaviors. While in WT, the catalytic machinery stably retains in the activated state; in R298A it remains largely collapsed in the inactivated state, thus implying that two states are not only structurally very distinguishable but also dynamically well separated. Surprisingly, in N214A the catalytic dyad becomes dynamically unstable and many residues constituting the catalytic machinery jump to sample the conformations highly resembling those of R298A. Therefore, the N214A mutation appears to trigger the dramatic change of the enzyme dynamics in the context of the dimeric form which ultimately inactivates the catalytic machinery. The present MD simulations represent the longest reported so far for the SARS-CoV 3CLpro, unveiling that its catalysis is critically dependent on the dynamics, which can be amazingly modulated by the extra domain. Consequently, mediating the dynamics may offer a potential avenue to inhibit the SARS-CoV 3CLpro
Data Descriptor : A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins
Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.Peer reviewe
A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins
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