Fiber-optic control and thermometry of single-cell thermosensation logic

Thermal activation of transient receptor potential (TRP) cation channels is one of the most striking examples of temperature-controlled processes in cell biology. As the evidence indicating the fundamental role of such processes in thermosensation builds at a fast pace, adequately accurate tools that would allow heat receptor logic behind thermosensation to be examined on a single-cell level are in great demand. Here, we demonstrate a specifically designed fiber-optic probe that enables thermal activation with simultaneous online thermometry of individual cells expressing genetically encoded TRP channels. This probe integrates a fiber-optic tract for the delivery of laser light with a two-wire microwave transmission line. A diamond microcrystal fixed on the fiber tip is heated by laser radiation transmitted through the fiber, providing a local heating of a cell culture, enabling a well-controlled TRP-assisted thermal activation of cells. Online local temperature measurements are performed by using the temperature-dependent frequency shift of optically detected magnetic resonance, induced by coupling the microwave field, delivered by the microwave transmission line, to nitrogen—vacancy centers in the diamond microcrystal. Activation of TRP channels is verified by using genetically encoded fluorescence indicators, visualizing an increase in the calcium flow through activated TRP channels

The Efficiency of Various Fire Protectants for Wooden Structures

The article deals with the scientific problem of the development and application of various fire protective compositions for wooden structures. Based on the results of theoretical and experimental studies, the authors for the first time attempted to state the influence of the chemical nature and mechanism of flame retardant action on the effectiveness of fire protection means. When assessing the effectiveness of fire protection, the authors paid special attention to the key parameters that determine the fire resistance of wooden structures. The possibility of developing effective fire protection systems, capable not only to provide a certain group of fire protection efficiency but also to influence the parameters of the charring process and the intensity of wood heating temperature is shown. Complex mechanisms of bloating (intumescence) and carbonization in combination with the mechanism of regulating the process of carbonization and wood carbonization, are able to provide the protected material with effective resistance to high temperatures (fire). The use of such types of fire protection allows forming an independent scientific direction associated with the development and use of fire protection systems contributing not only to the effective reduction of fire danger of wood and materials based on it but also to increasing the fire resistance of wooden structures

Оptical wave fields measurement by digital holography methods

The solution of a wide range of research and application problems of modern science and technology is connected to the measurement of the wave field of optical radiation. The methods of digital holography allow not only to improve the accuracy of measurements of optical wave field parameters, but also to increase the compactness of devices without losing speed. Digital holography gives a push to the development of new approaches to the construction of devices such as a wave front sensor.The study was supported by the Ministry of Education and Science of the Russian Federation: agreement No. 14.577.21.0258 of September 26, 2017 (project identifier RFMEFI57717X0258)

Triggering pulse generators developed for the high-voltage dischargers of magnetic systems and for the generator of pulse voltages used by the relativistic electron beam accelerator "TEMP-B"

The pulse generators were developed to trigger the high-voltage dischargers of magnetic systems and the dischargers of the generators of pulsed voltages used by the relativistic electron beam (REB) accelerator “TEMP-B”. The description of the triggering pulse generators designed by the NSC KIPT to actuate the dischargers of the pulsed voltage generators (PVG) and the dischargers of magnetic systems has been given. These are used by the commutation systems of capacitor banks with the stored energy margin in the range of 60 to 150 kJ. The generators provide the generation of voltage pulses with the amplitude of up to 20 kV.Розроблено генератори імпульсів для запуску високовольтних розрядників магнітних систем і генератора імпульсних напруг прискорювача релятивістських електронних пучків (РЕП) «ТЕМП-Б». Приведено опис генераторів і розглянута їх робота з розрядниками, спроектованими в ННЦ ХФТІ, які використовуються в системах комутації конденсаторних батарей з енергетичним запасом від 60 до 150 кДж. Генератори забезпечують отримання імпульсів напруги з амплітудою до 20 кВ.Разработаны генераторы импульсов для запуска высоковольтных разрядников магнитных систем и генератора импульсных напряжений ускорителя релятивистских электронных пучков (РЭП) «ТЕМП-Б». Приведено описание генераторов и рассмотрена их работа с разрядниками, спроектированными в ННЦ ХФТИ, которые используются в системах коммутации конденсаторных батарей с энергетическим запасом от 60 до 150 кДж. Генераторы обеспечивают получение импульсов напряжения с амплитудой до 20 кВ

Monitoring the capacitor charge voltage in the pulse voltage generator using the accelerator of relativistic electron beams

Noise-protected high charge voltage meter was manufactured using terminal capacitors of the four-channel pulse voltage generator (PVG). The noise protection is provided by the use of communication lines with fiberoptic cables. This measuring device is successfully used for the relativistic electron beam (REB) accelerator “Temp-B” and it provides the measurement accuracy of ~ 0.5% in the electromagnetic noise environment.Виготовлений перешкодозахищений вимірювач високої зарядної напруги на кінцевих конденсаторах чотириканального генератора імпульсної напруги (ГІН). Перешкодозахищеність забезпечується застосуванням ліній зв'язку з використанням оптоволоконного кабеля. Даний вимірювач успішно використовується на прискорювачі РЕП «Темп-Б» і забезпечує точність вимірювання ~ 0,5% в умовах сильних електромагнітних перешкод.Изготовлен помехозащищенный измеритель высокого зарядного напряжения на оконечных конденсаторах четырехканального генератора импульсного напряжения (ГИН). Помехозащищённость обеспечивается применением линий связи с использованием оптоволоконного кабеля. Данный измеритель успешно применяется на ускорителе РЭП «Темп-Б» и обеспечивает точность измерения ~ 0,5% в условиях сильных электромагнитных помех

Diagnostic module for the radiation beam system “TEMP-B”

The power module designed for the calibration and adjustment of the units and components of microsecond accelerator of relativistic electron beams (REB) “Temp-B” has been developed and manufactured. The noise immune gauge of high charging voltages of the terminal capacitors used by four-channel pulse voltage generator (PVG) and the discharger operating in the broad band of charging voltages have been manufactured. The methods developed using the module and the manufactured noise immune gauge of high charging voltages were applied to the accelerator “Temp-B”.Разработан и изготовлен силовой модуль для калибровки и отладки узлов и элементов микросекундного ускорителя релятивистских электронных пучков (РЭП) “Темп-Б”. Изготовлены помехозащищённый измеритель высокого зарядного напряжения на оконечных конденсаторах четырёхканального генератора импульсного напряжения (ГИН) и разрядник, работающий в широком диапазоне зарядных напряжений. Разработанные на модуле методики и изготовленный помехозащищённый измеритель высокого зарядного напряжения применены на ускорителе “Темп-Б”.Розроблено та виготовлено силовий модуль для калібрування і налагодження вузлів та елементів мікросекундного прискорювача релятивістських електронних пучків (РЕП) “Темп-Б”. Виготовлено перешкодозахищений вимірювач високої зарядної напруги на кінцевих конденсаторах чотириканального генератора імпульсної напруги (ГІН) та розрядник, що працює в широкому діапазоні розрядних напруг. Розроблені на модулі методики і виготовлений перешкодозахищений вимірювач високої зарядної напруги застосовані на прискорювачі “Темп-Б”

Current status of turbulent dynamo theory: From large-scale to small-scale dynamos

Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers. It is argued that all the different cases show similarities at intermediate length scales. On the other hand, in the presence of helicity of the turbulence, power develops on large scales, which is not present in non-helical small-scale turbulent dynamos. At small length scales, differences occur in connection with the dissipation cutoff scales associated with the respective value of the magnetic Prandtl number. These differences are found to be independent of whether or not there is large-scale dynamo action. However, large-scale dynamos in homogeneous systems are shown to suffer from resistive slow-down even at intermediate length scales. The results from simulations are connected to mean field theory and its applications. Recent work on helicity fluxes to alleviate large-scale dynamo quenching, shear dynamos, nonlocal effects and magnetic structures from strong density stratification are highlighted. Several insights which arise from analytic considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue "Magnetism in the Universe" (ed. A. Balogh

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure