Superconducting atomic contacts under microwave irradiation

We have measured the effect of microwave irradiation on the dc current-voltage characteristics of superconducting atomic contacts. The interaction of the external field with the ac supercurrents leads to replicas of the supercurrent peak, the well known Shapiro resonances. The observation of supplementary fractional resonances for contacts containing highly transmitting conduction channels reveals their non-sinusoidal current-phase relation. The resonances sit on a background current which is itself deeply modified, as a result of photon assisted multiple Andreev reflections. The results provide firm support for the full quantum theory of transport between two superconductors based on the concept of Andreev bound states

Модернизация автоматизированной системы управления подстанцией 500 кВ Холмогорская

Модернизация АСУ ТП ПС Холмогорская 500 кВ до первой, второй и третьей архитектуры цифровой подстанцииModernization of the automated control system of the Kholmogorskaya 500 kV substation to the first, second and third digital substation architectur

Разработка алгоритма верификации параметров линии электропередачи в расчетных моделях и его программная реализация

Объектом исследования являются методы верификации параметров ЛЭП в математических моделях для расчетов установившихся режимов электроэнергетических систем и их программная реализация. В ходе разработки приложения использовались стандартные библиотеки, а также библиотеки, находящиеся в открытом доступе. Для взаимодействия с ОИК СК-2007 использовались стандартные инструменты для доступа к данным. В ходе разработки алгоритмов использовались отечественные и зарубежные методики определения параметров линии электропередачи, алгоритм учитывает требования к созданию и актуализации расчетной модели для расчетов установившихся режимов.The objects of study are methods for verifying the parameters of power lines in mathematical models for calculations for the establishment of energy systems and their software implementation. During the development of the application, standard libraries were used, as well as libraries that are in the public domain. To interact with the OIC SK-2007, standard tools for accessing data were used. During the development of the algorithms, national and foreign methods for determining the parameters of power lines were used, the algorithm takes into account the requirements for the development and updating of calculations for models established for calculations

Conductance of the single-electron transistor: A comparison of experimental data with Monte Carlo calculations

We report on experimental results for the conductance of metallic single-electron transistors as a function of temperature, gate voltage and dimensionless conductance. In contrast to previous experiments our transistor layout allows for a direct measurement of the parallel conductance and no ad hoc assumptions on the symmetry of the transistors are necessary. Thus we can make a comparison between our data and theoretical predictions without any adjustable parameter. Even for rather weakly conducting transistors significant deviations from the perturbative results are noted. On the other hand, path integral Monte Carlo calculations show remarkable agreement with experiments for the whole range of temperatures and conductances.Comment: 8 pages, 7 figures, revtex4, corrected typos, submitted to PR

Stromal cells support the survival of human primary chronic lymphocytic leukemia (CLL) cells through Lyn-driven extracellular vesicles

Introduction In chronic lymphocytic leukemia (CLL), the tumor cells receive survival support from stromal cells through direct cell contact, soluble factors and extracellular vesicles (EVs). The protein tyrosine kinase Lyn is aberrantly expressed in the malignant and stromal cells in CLL tissue. We studied the role of Lyn in the EV-based communication and tumor support. Methods We compared the Lyn-dependent EV release, uptake and functionality using Lyn-proficient (wild-type) and -deficient stromal cells and primary CLL cells. Results Lyn-proficient cells caused a significantly higher EV release and EV uptake as compared to Lyn-deficient cells and also conferred stronger support of primary CLL cells. Proteomic comparison of the EVs from Lyn-proficient and -deficient stromal cells revealed 70 significantly differentially expressed proteins. Gene ontology studies categorized many of which to organization of the extracellular matrix, such as collagen, fibronectin, fibrillin, Lysyl oxidase like 2, integrins and endosialin (CD248). In terms of function, a knockdown of CD248 in Lyn+ HS-5 cells resulted in a diminished B-CLL cell feeding capacity compared to wildtype or scrambled control cells. CD248 is a marker of certain tumors and cancer-associated fibroblast (CAF) and crosslinks fibronectin and collagen in a membrane-associated context. Conclusion Our data provide preclinical evidence that the tyrosine kinase Lyn crucially influences the EV-based communication between stromal and primary B-CLL cells by raising EV release and altering the concentration of functional molecules of the extracellular matrix

Synthesis of quaternary aryl phosphonium salts: photoredox-mediated phosphine arylation

We report a synthesis method for the construction of quaternary aryl phoshonium salts at ambient temperature. The regiospecific reaction invovles the coupling of phosphines with aryl radicals derived from diaryliodonium salts under photoredox conditions

Fractionation of eucalyptus globulus wood by glycerol-water pretreatment: optimization and modeling

A glycerol-organosolv process can be a good alternative for Eucalyptus wood fractionation into its main compounds, improving the enzymatic saccharification of the cellulose. A study of process variables - glycerol−water percent content, temperature, and process time - was carried out using a Box-Behnken experimental design. The cellulose obtained from pretreated solids was recovered almost quantitatively, leading to a solid with a high percentage of cellulose (77 g/100 g of pretreated solid), low lignin content (9 g/100 g of pretreated solid), and 18% of residual hemicellulose in the solid at 200 °C, 56% of glycerol−water and 69 min. The enzymatic saccharification was enhanced achieving 98% cellulose-to-glucose conversion (under conditions: liquid to solid ratio 20 g/g and enzyme loading 20 FPU/g of solid). This study contributes to the improvement of biomass fractionation by exploring an eco-friendly treatment which allows for almost complete wood fractionation into constituents and high levels of glucose recovery available for subsequent yeast fermentation to bioethanol.The authors A. Romani and F. B. Pereira thank to the Portuguese Foundation for Science and Technology (FCT, Portugal) for their fellowships (grant number: SFRH/BPD/77995/2011 and SFRH/BD/64776/2009, respectively)