Controlling the quantum number distribution and yield of Rydberg states via the duration of the laser pulse

We show that the distribution of quantum numbers of Rydberg states does not only depend on the field strength and wavelength of the laser which the atom is exposed to, but that it also changes significantly with the duration of the laser pulse. We provide an intuitive explanation for the underlying mechanism and derive a scaling law for the position of the peak in the quantum number distribution on the pulse duration. The new analytic description for the electron's movement in the superposed laser and Coulomb field (applied in the study of quantum numbers) is then used to explain the decrease of the Rydberg yield with longer pulse durations. This description stands in contrast to the concepts that explained the decrease so far and also reveals that approximations which neglect Coulomb effects during propagation are not sufficient in cases such as this.Comment: 8 pages, 8 figure

Oxygen, nitrogen and sulphide fluxes in the Black Sea

The fluxes and production/consumption rates of oxygen, nitrate, ammonium and sulphide are estimated in the paper utilising results of the 1.5-dimensional stationary model of vertical exchange in the Black Sea (Samodurov & Ivanov, 1998). The profiles of the vertical flux and rate of production/consumption of these substances have revealed a number of intriguing features in the biogeochemical nature of the Black Sea. An approximate redox balance of the counter-fluxes of nitrate and ammonium into the sub-oxic zone has been revealed confirming that intensive denitrification may be the primary loss of nitrogen in the Black Sea. A low ratio of the nitrate stock to the flux of nitrate from the oxycline confirms the possibility of prominent changes in the distribution of nitrate on the time scale of a year. The ratio of the nitrate to oxygen vertical flux has revealed a lack of nitrate in the oxycline above the nitrate maximum. The lateral (related to the "Bosporus plume") flux of oxygen in the layer of the main pycnocline appears to be very important for the existing biogeochemical structure of the Black sea water column being the reason of sulphide consumption inside the anoxic zone and changes in the ammonium-sulphide stoichiometry of the anoxic zone, the primary reason of the existence of the sub-oxic layer and the basic reason of relative stability of the sulphide onset

N=4 supersymmetric Eguchi-Hanson sigma model in d=1

We show that it is possible to construct a supersymmetric mechanics with four supercharges possessing not conformally flat target space. A general idea of constructing such models is presented. A particular case with Eguchi--Hanson target space is investigated in details: we present the standard and quotient approaches to get the Eguchi--Hanson model, demonstrate their equivalence, give a full set of nonlinear constraints, study their properties and give an explicit expression for the target space metric.Comment: LaTeX, 9 page

Ventilation of the Black Sea pycnocline on seasonal and interannual time scales

The paper is a description of temporal variability of winter cooling conditions and estimation of effective cross-isopycnal mixing rates in the Black Sea. Data averaging versus salinity / sigma-t scale was used to filter effects of local dynamics. It is shown that traces of winter mixing events appear well preserved in the temperature-salinity structure, due to the peculiarities of the Black Sea where temperature often acts as a passive tracer with a smaller contribution to density as compared to salinity. Vertical distribution of the magnitudes of temperature oscillations indicates that the convection events have limited effects in modifying the structure of the middle and lower pycnocline on a seasonal time scale. However, long-term fluctuations are well recognised. The magnitudes of the seasonal and long-term temperature fluctuations are comparable only in the upper pycnocline. Three major cooling events can be distinguished from the record of the pycnocline temperature for the past 75 years. The intensive cooling occurred in the late 1920s - early 1930s, early 1950s and late 1980s - early 1990s. Partial renewal of the water of the cold intermediate layer core took place approximately once in two years. The period when convection causes erosion of the pycnocline lasts for only a week. It is shown that a lateral source of heat and salt exists for the upper pycnocline, where it is the cold intermediate water, and for the lower pycnocline, the layer below S@ 20.5, where this lateral source of salt and heat is maintained by disintegrating Bosphorus plume

Стратегия экспериментальных исследований интерактомики целевых белков

It is known that intermolecular interactions of proteins and peptides play a critical role in life processes. Such interactions can be either directly related to the implementation of various functions or play the role of a regulator. Currently, there is no doubt that the majority of proteins function as part of various molecular complexes, the formation of which occurs due to protein-protein interactions (PPIs), the totality of which can be defined as the “protein interactome”. Protein subinteractome studies are critical for studying the functions and regulatory mechanisms of unknown or poorly annotated proteins, understanding the architecture of intracellular molecular machines, and the design of PPI modulators. Previously, we used combinations of experimental approaches, as well as analytical and preparative methods, to study the subinteractomes of functionally different cellular proteins, which allowed us to identify the protein subinteractomes of several clinically significant human proteins. The purpose of this work was to conceptualize the principles of the experimental platform we developed for studying protein subinteractomes and to describe its features in detail.Известно, что межмолекулярные взаимодействия белков и пептидов играют важнейшую роль в процессах жизнедеятельности. Такие взаимодействия могут быть как напрямую связаны с осуществлением различных функций, так и играть роль регулятора. В настоящее время не вызывает сомнения тот факт, что большинство белков функционирует в составе различных молекулярных комплексов. Их формирование происходит за счёт белок-белковых взаимодействий (ББВ), совокупность которых можно определить как “белковый интерактом”. Исследования белковых субинтерактомов очень важны для изучения функций и механизмов регуляции неизвестных или плохо аннотированных белков, понимания архитектуры внутриклеточных молекулярных машин, а также дизайна модуляторов ББВ. Ранее мы применяли комбинации экспериментальных подходов, а также аналитических и препаративных методов для изучения субинтерактомов разных в функциональном отношении клеточных белков, что позволило идентифицировать белковые субинтерактомы некоторых клинически значимых белков человека. В данной работе мы интегрировали полученные ранее результаты в виде экспериментальной платформы, принципы которой представлены блок-схемами. Эти блок-схемы могут помочь широкому кругу читателей выполнить дизайн своих исследований в области изучения белковых субинтерактомов

Experimental Study of Coherent Summation of Radiation from Two Widely Aperture Pulsed

Emission of two high-power pulsed CO2-lasers with a transverse discharge at atmospheric pressure in the active medium and the output beam aperture 100х100 mm, united by a joint unstable telescopic reso-nator, was coherently summarized under conditions of real ground-level trackon the screen surface, which was remote from output mirror of the laser at a distance of 263 m. Output Brewster windows of laser cu-vettes were manufactured from single-crystal plates of sodium chloride which had a diameter of 300 mm. Mirrors for resonator and optical circuit were manufactured from oxygen-free copper. Active medium - a mixture of gases: CO2: N2: He in the ratio 1 : 2 : 3. Laser pulse duration is 5 microseconds. During the ex-periment, when summing on the screen 2-laser beams at the lowest possible convergence angle of rays, the interference pattern was registered. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3610

Сравнительный SPR анализ межмолекулярных взаимодействий с использованием оригинального чипа Biacore CM5 и его аналога CMD500M

Currently, users of Biacore SPR biosensors (“Cytiva”, USA) are faced with sanctions restrictions on the purchase of consumables (primarily optical chips) for this type of equipments. In this regard, the use of commercially available analogues of the optical chips has become relevant. In this work, a comparative study of molecular interactions was performed on a Biacore X100 SPR biosensor using an original Biacore CM5 optical chip (“Cytiva”, USA) and its analogue CMD500M (“XanTec bioanalytics GmbH”, Germany). Protein A was immobilized on both chips as a molecular ligand, often used in scientific research and biotechnological works to immobilize antibodies on various carriers (biosensor chips, sorbents, nano- and microparticles). An IgG antibody was used as a protein analyte. A comparative study of the interaction of various concentrations of antibodies with protein A immobilized on two versions of the chips was carried out. The values of the kinetic rate constants for the association (kon) and dissociation (koff) of complexes, as well as the equilibrium dissociation constant (Kd), were calculated from the obtained sensorgrams using the interaction model 1:1 (Langmuir) binding. The results of comparative measurements showed similar values of the rate constants and interaction affinities. The differences between the values of kon, koff and Kd were 18%, 10% and 9%, respectively. Thus, this study confirmed the interchangeability of the original SPR chips CM5 and their analogues CMD500M.В настоящее время пользователи SPR биосенсоров Biacore (“Cytiva”, США) столкнулись с санкционными ограничениями по закупке расходных материалов для данного оборудования, в первую очередь оптических чипов. В связи с этим стало актуальным использование их коммерчески доступных аналогов. В данной работе на SPR биосенсоре Biacore X100 было выполнено сравнительное исследование молекулярных взаимодействий с использованием оригинального оптического чипа Biacore CM5 (“Cytiva”) и его аналога CMD500M (“XanTec bioanalytics GmbH”, Германия). В качестве молекулярного лиганда на чипе был иммобилизован белок А, который часто используется в научных исследованиях и биотехнологических работах для иммобилизации антител на различных носителях (биосенсорные чипы, сорбенты, нано- и микрочастицы). В качестве белкового аналита был использован препарат антител типа IgG. Было выполнено сравнительное исследование взаимодействия различных концентраций антител с иммобилизованным на двух вариантах чипов белком А. Величины кинетических констант скоростей образования (kon) и распада (koff) комплексов, а также равновесной константы диссоциации комплекса (Kd), были рассчитаны из полученных наборов сенсограмм с использованием модели взаимодействия 1:1 (Langmuir) binding. Результаты сравнительных измерений показали близкие значения констант скоростей и аффинности взаимодействия (различия между величинами kon, koff и Kd составили 18%, 10% и 9% соответственно). Таким образом, данное исследование подтвердило практически полную взаимозаменяемость оригинальных SPR чипов CM5 и их аналогов CMD500M

Perfection of an Energy-Economic and Environmental Parameters of the Ground Source Heat Pump Systems with Preventing Freezing of the Soil around Ground Pipes

This article is devoted to the methods for perfection of energy, economic factors, environmental factors and work modes of the ground source heat pump systems with the account of climate conditions. The purpose of the work is to predict and prevent freezing of the soil during long term of exploitation of the low-power and high-power ground source heat pump systems for jus-tifying rational conditions of implementation GSHP in Ukraine and South-East Regions of Eu-rope. This goal is achieved by solving the following problems: determining the energy-economic and environmental factors based on considering the work modes of the ground source heat pumps; evaluation of the operating efficiency of ground source heat pump systems based on minimizing fuel consumption and greenhouse gas emissions; perfection of solutions enable im-plementation of ground source heat pumps friendly to the environment and justifying rational conditions of implementation the ground source heat pumps for residential sector. The important results of the work are the obtained and analyzed data on the influence of energy and economic factors both environmental criteria on the work modes and scheme-constructive solutions of ground source heat pumps. Modeling of heat exchange processes in the soil around the soil tube shows that in order to avoid freezing of the soil, the minimum permissible specific number of vertical tubes should be at least 0.12–0.15 pieces/m2 of heated area. The significance of the re-sults consists in the possibility of using the results of numerical simulation for preventing freez-ing of the soil around ground pipes of the ground source heat pump systems

Phonon squeezing via correlations in the superconducting electron-phonon interaction

Superconductivity in the conventional BCS model with correlated squeezed phonons is discussed. It is shown that the energy gap and the critical temperature are maximally enhanced in an optimum and finite range of squeezed coupling. For finite-squeezed coupling the ratio 2Δ/Tc becomes coupling-constant dependent and increases beyond the BCS value of 3.53. Ion-mass dependence of the squeezed coupling constant can yield variations of the isotope exponent from its conventional BCS value of 0.5. © 1995 The American Physical Society