Photoelectrochemical Reactions at an Anthracene Cathode

Investigation of the peculiarities of the photoconductivity of an anthracene cathode in the redox system iodine-iodide has supplied information on the kinetics of photoelectrochemical reactions injecting holes into anthracene. The effect of the surface coverage of anthracene with adsorbed iodine, the dielectric constant of the solvent, and of the energy of exciting photons on the photoconductivity of an anthracene cathode has been studied. It is shown that at photon energies from 3.8 to 5.0 eV, greater than the forbidden zone width, the conduction band electrons participate in the iodine reduction reaction. In the spectral region of singlet absorption of anthracene, excitons participate in the electrochemical charge separation reaction. In the case of contact with a polar solvent, excitons break up at the surface levels formed by adsorbed iodine. In the case of contact with a weakly-polar solvent, excitation is transferred to adsorbed iodine. In the spectral region of weak optical absorption of anthracene, iodine particles excited directly by the light that had passed through the crystal participate in the reaction

Photoelectrochemical Reactions at an Anthracene Cathode

Investigation of the peculiarities of the photoconductivity of an anthracene cathode in the redox system iodine-iodide has supplied information on the kinetics of photoelectrochemical reactions injecting holes into anthracene. The effect of the surface coverage of anthracene with adsorbed iodine, the dielectric constant of the solvent, and of the energy of exciting photons on the photoconductivity of an anthracene cathode has been studied. It is shown that at photon energies from 3.8 to 5.0 eV, greater than the forbidden zone width, the conduction band electrons participate in the iodine reduction reaction. In the spectral region of singlet absorption of anthracene, excitons participate in the electrochemical charge separation reaction. In the case of contact with a polar solvent, excitons break up at the surface levels formed by adsorbed iodine. In the case of contact with a weakly-polar solvent, excitation is transferred to adsorbed iodine. In the spectral region of weak optical absorption of anthracene, iodine particles excited directly by the light that had passed through the crystal participate in the reaction

Методы получения наночастиц и их размерно-чувствительные физические параметры

The varieties of the methods of nanoparicles synthesis are discussed in this review. Wet and dry chemistry processes, pulse sonoelectrochemistry, methods with use of supercritical CO2, and far from equilibrium systems of two liquids are considered and compared.Possible role of dissipative phenomena during the processes of new nanoparticles creation is under special attention.Настоящий обзор посвящен методам получения наночастиц. Рассмотрены методы «мокрой» и «сухой» химии, соноэлектрохимический метод, получение наночастиц с использованием сверхкритического диоксида углерода, границы двух жидкостей и др. Обсуждается возможное влияние диссипативных процессов в среде, где рождаются наночастицы, на их физические параметры

Enhancing Resource Management through Prediction-based Policies

Task-based programming models are emerging as a promising alternative to make the most of multi-/many-core systems. These programming models rely on runtime systems, and their goal is to improve application performance by properly scheduling application tasks to cores. Additionally, these runtime systems offer policies to cope with application phases that lack in parallelism to fill all cores. However, these policies are usually static and favor either performance or energy efficiency. In this paper, we have extended a task-based runtime system with a lightweight monitoring and prediction infrastructure that dynamically predicts the optimal number of cores required for each application phase, thus improving both performance and energy efficiency. Through the execution of several benchmarks in multi-/many-core systems, we show that our prediction-based policies have competitive performance while improving energy efficiency when compared to state of the art policies.Comment: Postprint submitted and published at Euro-Par2020: International European Conference on Parallel and Distributed Computing (Springer) (https://link.springer.com/chapter/10.1007%2F978-3-030-57675-2_31

Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors

Quasiclassic Uzadel equations for two-band superconductors in the dirty limit with the account of both intraband and interband scattering by nonmagnetic impurities are derived for any anisotropic Fermi surface. From these equations the Ginzburg-Landau equations, and the critical temperature $T_c$ are obtained. An equation for the upper critical field, which determines both the temperature dependence of $H_{c2}(T)$ and the orientational dependence of $H_{c2}(\theta)$ as a function of the angle $\theta$ between ${\bf H}$ and the c-axis is obtained. It is shown that the shape of the $H_{c2}(T)$ curve essentially depends on the ratio of the intraband electron diffusivities $D_1$ and $D_1$, and can be very different from the standard one-gap dirty limit theory. In particular, the value $H_{c2}(0)$ can considerably exceed $0.7T_cdH_{c2}/dT_c$, which can have important consequences for applications of $MgB_2$. A scaling relation is proposed which enables one to obtain the angular dependence of $H_{c2}(\theta)$ from the equation for $H_{c2}$ at ${\bf H}\| c$. It is shown that, depending on the relation between $D_1$ and $D_2$, the ratio of the upper critical field $H_{c2}^\|/H_{c2}^\perp$ for ${\bf H}\| ab$ and ${\bf H}\perp ab$ can both increase and decrease as the temperature decreases. Implications of the obtained results for $MgB_2$ are discussed

Observation of narrow baryon resonance decaying into pKs0pK^0_s in pA-interactions at 70GeV/c70 GeV/c with SVD-2 setup

SVD-2 experiment data have been analyzed to search for an exotic baryon state, the $\Theta^+$-baryon, in a $pK^0_s$ decay mode at $70 GeV/c$ on IHEP accelerator. The reaction $pA \to pK^0_s+X$ with a limited multiplicity was used in the analysis. The $pK^0_s$ invariant mass spectrum shows a resonant structure with $M=1526\pm3(stat.)\pm 3(syst.) MeV/c^2$ and $\Gamma < 24 MeV/c^2$. The statistical significance of this peak was estimated to be of $5.6 \sigma$. The mass and width of the resonance is compatible with the recently reported $\Theta^+$- baryon with positive strangeness which was predicted as an exotic pentaquark ($uudd\bar{s}$) baryon state. The total cross section for $\Theta^+$ production in pN-interactions for $X_F\ge 0$ was estimated to be $(30\div120) \mu b$ and no essential deviation from A-dependence for inelastic events $(\sim A^{0.7})$ was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some references added, minor typos correcte

Разработка метода получения pd - содержащих частиц для последующего синтеза электрокатализаторов

Platinum metals and their compounds are now widely used as catalysts for water electrolysis and fuel cells. We propose a new approach to the synthesis of nanoparticles. As model experiment we realized synthesis of palladium diacetate nanoparticles of controlled size. As special condition for new phase grow was chosen far from equilibrium boundary between two liquids [2]. Under this condition gradient of chemical potential the water - tetrahydrofuran (THF) interface was a powerful regulating factor of the palladium diacetate (II) particle size.Описан метод получения наноматериалов в неравновесном переходном слое, возникающем при приведении в контакт двух различных по своей химической природе смешивающихся жидкостей. Метод апробирован для получения Pd-содержащих наночастиц контролируемого размера, которые будут в дальнейшем использованы для получения электрокатализаторов. Предложенный метод не предполагает применения поверхностно-активных добавок, модифицирующих поверхность, что является ключевым моментом в процессах синтеза катализаторов. Рассмотрено влияние различных факторов на размер частиц диацетата палладия(II), образующихся в переходном слое на границе раздела вода - тетрагидрофуран (ТГФ)

Reorganization of the nuclear lamina and cytoskeleton in adipogenesis

A thorough understanding of fat cell biology is necessary to counter the epidemic of obesity. Although molecular pathways governing adipogenesis are well delineated, the structure of the nuclear lamina and nuclear-cytoskeleton junction in this process are not. The identification of the ‘linker of nucleus and cytoskeleton’ (LINC) complex made us consider a role for the nuclear lamina in adipose conversion. We herein focused on the structure of the nuclear lamina and its coupling to the vimentin network, which forms a cage-like structure surrounding individual lipid droplets in mature adipocytes. Analysis of a mouse and human model system for fat cell differentiation showed fragmentation of the nuclear lamina and subsequent loss of lamins A, C, B1 and emerin at the nuclear rim, which coincides with reorganization of the nesprin-3/plectin/vimentin complex into a network lining lipid droplets. Upon 18 days of fat cell differentiation, the fraction of adipocytes expressing lamins A, C and B1 at the nuclear rim increased, though overall lamin A/C protein levels were low. Lamin B2 remained at the nuclear rim throughout fat cell differentiation. Light and electron microscopy of a subcutaneous adipose tissue specimen showed striking indentations of the nucleus by lipid droplets, suggestive for an increased plasticity of the nucleus due to profound reorganization of the cellular infrastructure. This dynamic reorganization of the nuclear lamina in adipogenesis is an important finding that may open up new venues for research in and treatment of obesity and nuclear lamina-associated lipodystrophy

The Function of Cortactin in the Clustering of Acetylcholine Receptors at the Vertebrate Neuromuscular Junction

Background: Postsynaptic enrichment of acetylcholine receptors (AChRs) at the vertebrate neuromuscular junction (NMJ) depends on the activation of the muscle receptor tyrosine MuSK by neural agrin. Agrin-stimulation of MuSK is known to initiate an intracellular signaling cascade that leads to the clustering of AChRs in an actin polymerization-dependent manner, but the molecular steps which link MuSK activation to AChR aggregation remain incompletely defined. Methodology/Principal Findings: In this study we used biochemical, cell biological and molecular assays to investigate a possible role in AChR clustering of cortactin, a protein which is a tyrosine kinase substrate and a regulator of F-actin assembly and which has also been previously localized at AChR clustering sites. We report that cortactin was co-enriched at AChR clusters in situ with its target the Arp2/3 complex, which is a key stimulator of actin polymerization in cells. Cortactin was further preferentially tyrosine phosphorylated at AChR clustering sites and treatment of myotubes with agrin significantly enhanced the tyrosine phosphorylation of cortactin. Importantly, forced expression in myotubes of a tyrosine phosphorylation-defective cortactin mutant (but not wild-type cortactin) suppressed agrin-dependent AChR clustering, as did the reduction of endogenous cortactin levels using RNA interference, and introduction of the mutant cortactin into muscle cells potently inhibited synaptic AChR aggregation in response to innervation. Conclusion: Our results suggest a novel function of phosphorylation-dependent cortactin signaling downstream fro

Cинтез наночастиц Y(OH)CO3 и Y2О3 при использовании жидких межфазных границ и дальнейшая модификация их поверхности палладием

The nano-composite materials with different morphology and structure, including yttrium basic carbonate or yttrium oxide and palladium metal are obtained. The optimal conditions for synthesis of stable nanoparticles of yttrium basic carbonate are defined. It is established that yttrium basic carbonate goes to the oxide at 900 °C. Samples of nanomaterials were characterized by transmission electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy.Получены наноразмерные композиционные материалы различной морфологии и структуры, включа-ющие гидроксокарбонат либо оксид иттрия и металлический палладий. Определены оптимальные условия синтеза стабильных наночастиц гидроксокарбоната иттрия, которые при температуре 900°С переходят в соответствующий оксид. Образцы наноматериалов охарактеризованы методами электронной просвечивающей микроскопии, ИК спектроскопии, рентгенофазового анализа, рентгеновской фотоэлектронной спектроскопии