Specific Excision of the Selenocysteine tRNA\u3csup\u3e [Ser]Sec\u3c/sup\u3e (\u3ci\u3eTrsp\u3c/i\u3e) Gene in Mouse Liver Demonstrates an Essential Role of Selenoproteins in Liver Function

Selenium is essential in mammalian embryonic development. However, in adults, selenoprotein levels in several organs including liver can be substantially reduced by selenium deficiency without any apparent change in phenotype. To address the role of selenoproteins in liver function, mice homozygous for a floxed allele encoding the selenocysteine (Sec) tRNA [Ser]Sec gene were crossed with transgenic mice carrying the Cre recombinase under the control of the albumin promoter that expresses the recombinase specifically in liver. Recombination was nearly complete in mice 3 weeks of age, whereas liver selenoprotein synthesis was virtually absent, which correlated with the loss of Sec tRNA [Ser]Sec and activities of major selenoproteins. Total liver selenium was dramatically decreased, whereas levels of low molecular weight selenocompounds were little affected. Plasma selenoprotein P levels were reduced by about 75%, suggesting that selenoprotein P is primarily exported from the liver. Glutathione S-transferase levels were elevated in the selenoprotein-deficient liver, suggesting a compensatory activation of this detoxification program. Mice appeared normal until about 24 h before death. Most animals died between 1 and 3 months of age. Death appeared to be due to severe hepatocellular degeneration and necrosis with concomitant necrosis of peritoneal and retroperitoneal fat. These studies revealed an essential role of selenoproteins in liver function

Terms and Need Strategic Cooperation Mechanisms of Social and Economic Systems of the Region

The increasing complexity of the socio-economic systems and the increase in the state's functions in modern regional space becoming more common complex, multi-level strategic cooperation mechanisms. In such structures, the main elements of the control system are divided into several levels. Management levels are organizationally separate elements detected in the territorial structures of governance, for example, the subject of the Federation, municipal formation. Between the different levels of the system of separation of powers, responsibilities and functions of the power vertical. Within the framework of the powers assigned to them elements of the system have the right to independent decision-making. Developing of the Russian Federation system of market relations qualitatively increased value, role, authority and responsibility of regions to ensure the functioning and development of the territories, the growth of living standards of the population living in them. Enhanced functions of the organs of power in the federal subjects is accompanied by the simultaneous complexity of the mechanism of management decision-making, and the increasing influence of the variability of environmental factors. Under these circumstances, the effective activities of the regional administrations are not possible without the coordination and integration of their efforts, which can promote inter-regional cooperation. Keywords: regional economy, social and economic system, management mechanism JEL Classifications: Q27, R12, R5

Atomically thin boron nitride: a tunnelling barrier for graphene devices

We investigate the electronic properties of heterostructures based on ultrathin hexagonal boron nitride (h-BN) crystalline layers sandwiched between two layers of graphene as well as other conducting materials (graphite, gold). The tunnel conductance depends exponentially on the number of h-BN atomic layers, down to a monolayer thickness. Exponential behaviour of I-V characteristics for graphene/BN/graphene and graphite/BN/graphite devices is determined mainly by the changes in the density of states with bias voltage in the electrodes. Conductive atomic force microscopy scans across h-BN terraces of different thickness reveal a high level of uniformity in the tunnel current. Our results demonstrate that atomically thin h-BN acts as a defect-free dielectric with a high breakdown field; it offers great potential for applications in tunnel devices and in field-effect transistors with a high carrier density in the conducting channel.Comment: 7 pages, 5 figure

Smart City as the Basic Construct of the Socio-economic Development of Territories

The relevance of this topic is that any self-respecting city needs a development strategy that develops on the basis of the ideal representations of the future and opportunities. All of the city strive to achieve two fundamental goals. The first is to create a high-quality living environment, which is dictated by growing competition for investment and brains. The second objective - to ensure sustainable development, i.e. the search for the integrated (economic, social, transport, energy, environmental, etc.) model, which would guarantee a dignified existence for at least several generations of citizens. Currently in addressing the challenges of economic modernization and innovative development of Russia a key role to be played by information, knowledge, the widespread use of information and communication technologies, the problems of optimum use of natural resources and ecology, as well as the formation of the social environment, designed to provide optimal conditions for the work of participants the innovation process (Shkurkin, Shestopal, Gurieva, Blaginin and Gurianov 2016). In this context, the problem of creating smart cities is today one of the most pressing. Background of the idea of “smart” city and its development: increase in workload infrastructures. Keywords: Economic development, regional development, smart city, infrastructure, resources JEL Classifications: О13, R1

Macroeconomic Trends and Features of Regional Economy Development in the 21st Century

At present there is a tendency to the general Russian economic crisis and the disintegration of the economic space and various basic conditions of separate regions, which are focused on the market in the development of regions. Today the regions with a high concentration of stagnating and converting industries and the incomplete investment programs of development, the regions, which are directly dependent from raw material and food supply and also the districts, which have an intense ecological situation, where it is necessary to terminate the functioning of a number of the ecological harmful enterprises and to make measures for the social protection of the population of this region, are under more severe conditions. A number of the regions of the Far East, Siberia, the Urals and the Center are referred to these districts. The fundamentalization of Russia's integral economic space directly depends on a capital market by forming the system of joint stock companies, stock exchanges, commercial banks and funds for commodity and raw material resources. Commercial firms and entrepreneurs have a considerable potential in the questions about supplying the enterprises of various regions with material and technical resources, and the population with food. Keywords: macroeconomics, Gross Domestic Product (GDP), happiness index, consumer demand, capital, investment activity, integration, import substitution, capital market JEL Classifications: E01, O11, O20, R11, R1

Chiral photonic super-crystals based on helical van der Waals homostructures

Chirality is probably the most mysterious among all symmetry transformations. Very readily broken in biological systems, it is practically absent in naturally occurring inorganic materials and is very challenging to create artificially. Chiral optical wavefronts are often used for the identification, control and discrimination of left- and right-handed biological and other molecules. Thus, it is crucially important to create materials capable of chiral interaction with light, which would allow one to assign arbitrary chiral properties to a light field. In this paper, we utilized van der Waals technology to assemble helical homostructures with chiral properties (e. g. circular dichroism). Because of the large range of van der Waals materials available such helical homostructures can be assigned with very flexible optical properties. We demonstrate our approach by creating helical homostructures based on multilayer As$_2$S$_3$, which offers the most pronounced chiral properties even in thin structures due to its strong biaxial optically anisotropy. Our work showcases that the chirality of an electromagnetic system may emerge at an intermediate level between the molecular and the mesoscopic one due to the tailored arrangement of non-chiral layers of van der Waals crystals and without additional patterning

Exploring van der Waals materials with high anisotropy: geometrical and optical approaches

The emergence of van der Waals (vdW) materials resulted in the discovery of their giant optical, mechanical, and electronic anisotropic properties, immediately enabling countless novel phenomena and applications. Such success inspired an intensive search for the highest possible anisotropic properties among vdW materials. Furthermore, the identification of the most promising among the huge family of vdW materials is a challenging quest requiring innovative approaches. Here, we suggest an easy-to-use method for such a survey based on the crystallographic geometrical perspective of vdW materials followed by their optical characterization. Using our approach, we found As2S3 as a highly anisotropic vdW material. It demonstrates rare giant in-plane optical anisotropy, high refractive index and transparency in the visible range, overcoming the century-long record set by rutile. Given these benefits, As2S3 opens a pathway towards next-generation nanophotonics as demonstrated by an ultrathin true zero-order quarter-waveplate that combines classical and the Fabry-Perot optical phase accumulations. Hence, our approach provides an effective and easy-to-use method to find vdW materials with the utmost anisotropic properties.Comment: 11 pages, 5 figure

How close can one approach the Dirac point in graphene experimentally?

The above question is frequently asked by theorists who are interested in graphene as a model system, especially in context of relativistic quantum physics. We offer an experimental answer by describing electron transport in suspended devices with carrier mobilities of several 10^6 cm^2V^-1s^-1 and with the onset of Landau quantization occurring in fields below 5 mT. The observed charge inhomogeneity is as low as \approx10^8 cm^-2, allowing a neutral state with a few charge carriers per entire micron-scale device. Above liquid helium temperatures, the electronic properties of such devices are intrinsic, being governed by thermal excitations only. This yields that the Dirac point can be approached within 1 meV, a limit currently set by the remaining charge inhomogeneity. No sign of an insulating state is observed down to 1 K, which establishes the upper limit on a possible bandgap

The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella

High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe

A decade of intense research on two-dimensional (2D) atomic crystals has revealed that their properties can differ greatly from those of the parent compound. These differences are governed by changes in the band structure due to quantum confinement and are most profound if the underlying lattice symmetry changes. Here we report a high-quality 2D electron gas in few-layer InSe encapsulated in hexagonal boron nitride under an inert atmosphere. Carrier mobilities are found to exceed 103cm2V-1s-1and 104cm2V-1s-1at room and liquid-helium temperatures, respectively, allowing the observation of the fully developed quantum Hall effect. The conduction electrons occupy a single 2D subband and have a small effective mass. Photoluminescence spectroscopy reveals that the bandgap increases by more than 0.5eV with decreasing the thickness from bulk to bilayer InSe. The band-edge optical response vanishes in monolayer InSe, which is attributed to the monolayer's mirror-plane symmetry. Encapsulated 2D InSe expands the family of graphene-like semiconductors and, in terms of quality, is competitive with atomically thin dichalcogenides and black phosphorus.EU, EPSRC. The Royal Societ