Are there stable long-range ordered Fe(1-x)Cr(x) compounds?

The heat of formation of Fe-Cr alloys undergoes an anomalous change of sign at small Cr concentrations. This observation raises the question whether there are intermetallic phases present in this composition range. Here we report the discovery of several long-range ordered structures that represent ground state phases at zero Kelvin. In particular we have identified a structure at 3.7% Cr with an embedding energy which is 49 meV/Cr atom below the solid solution. This implies there is an effective long-range attractive interaction between Cr atoms. We propose that the structures found in this study complete the low temperature-low Cr region of the phase diagram.Comment: 3 pages, 2 figure

Improving the efficiency of fuel combustion with regard to the uncertainty of measuring oxygen concentration

Исследовано влияние метеорологических параметров окружающей среды на процесс сжигания топлива в котлоагрегатах. Установлена функциональная взаимосвязь между температурой, абсолютным давлением, относительной влажностью и объемной концентрацией кислорода в воздухе. Предложен способ повышения точности измерения коэффициента избытка воздуха для уменьшения потерь тепловой энергии в котлоагрегата

Методи локації місцезнаходження дефектів структури за сигналами акустичної емісії

A review of methods and algorithms for detecting spots of structural defects developing in products under load is given. These methods and algorithms are used in acoustic emission systems designed for locating the sources of acoustic radiationПриведен обзор методов и алгоритмов определения местонахождения дефектов структуры, развивающихся в изделиях при их нагружении, которые применяются в акустико-эмиссионных системах локации источников акустического излученияНаведено огляд методів та алгоритмів визначення місцезнаходження дефектів структури, що : розвиваються у виробах при їх навантаженні, які використовуються в акустоемісійних системах  локації джерел акустичного випромінюванн

Short-range order and precipitation in Fe-rich Fe-Cr alloys: Atomistic off-lattice Monte Carlo simulations

Short-range order (SRO) in Fe-rich Fe-Cr alloys is investigated by means of atomistic off-lattice Monte Carlo simulations in the semi-grand canonical ensemble using classical interatomic potentials. The SRO parameter defined by Cowley [Phys. Rev. B 77, 669 (1950)] is used to quantify the degree of ordering. In agreement with experiments a strong ordering tendency in the Cr distribution at low Cr concentrations (~< 5%) is observed, as manifested in negative values of the SRO parameters. For intermediate Cr concentrations (5% ~< c_Cr ~< 15%) the SRO parameter for the alpha-phase goes through a minimum, but at the solubility limit the alpha-phase still displays a rather strong SRO. In thermodynamic equilibrium for concentrations within the two-phase region the SRO parameter measured over the entire sample therefore comprises the contributions from both the alpha and alpha-prime phases. If both of these contributions are taken into account, it is possible to quantitatively reproduce the experimental results and interpret their physical implications. It is thereby shown that the inversion of the SRO observed experimentally is due to the formation of stable (supercritical) alpha-prime precipitates. It is not related to the loss of SRO in the alpha-phase or to the presence of unstable (subcritical) Cr precipitates in the alpha-phase.Comment: 9 pages, 8 figure

Mixed-mode Oscillations in Pyramidal Neurons Under Antiepileptic Drug Conditions

Subthreshold oscillations in combination with large-amplitude oscillations generate mixedmode oscillations (MMOs), which mediate various spatial and temporal cognition and memory processes and behavioral motor tasks. Although many studies have shown that canard theory is a reliable method to investigate the properties underlying the MMOs phenomena, the relationship between the results obtained by applying canard theory and conductancebased models of neurons and their electrophysiological mechanisms are still not well understood. The goal of this study was to apply canard theory to the conductance-based model of pyramidal neurons in layer V of the Entorhinal Cortex to investigate the properties of MMOs under antiepileptic drug conditions (i.e., when persistent sodium current is inhibited). We investigated not only the mathematical properties of MMOs in these neurons, but also the electrophysiological mechanisms that shape spike clustering. Our results show that pyramidal neurons can display two types of MMOs and the magnitude of the slow potassium current determines whether MMOs of type I or type II would emerge. Our results also indicate that slow potassium currents with large time constant have significant impact on generating the MMOs, as opposed to fast inward currents. Our results provide complete characterization of the subthreshold activities in MMOs in pyramidal neurons and provide explanation to experimental studies that showed MMOs of type I or type II in pyramidal neurons under antiepileptic drug conditions

Low-Frequency Electromagnetic Signals Observed before Strong Earthquakes

We consider two kinds of signals preceding earthquake (EQ): intensification of internal electromagnetic (EM) field – lithosphere emission (LE) and change of the Earth interior response function (RF). Several cases of LE before strong EQs were reviewed and analyzed, and preliminary portrait of LE precursor was compiled. LE can appear several times with lead time month(s), weeks, days, and hours and can attain amplitude of several hundreds of nT which not uniformly decreases with increasing distance from the source. Typical LE frequency content/maximum is 0.01–0.5 Hz. Data of 19 Japanese geomagnetic observatories for 20 years preceding the Tohoku EQ on March 11, 2011 were analyzed, and RFs (mainly induction vector) were calculated. At six observatories in 2008–2010, anomalous variations of RF were separated which can be identified as middle-term precursors. Applying the original method developed in Ukraine, a short-term two-month-long precursor of bay-like form was separated by phase data of observatory KNZ in the Boso peninsula where electrical conductivity anomaly was also discovered. Hypothetical explanation based on tectonic data is advanced: Boso anomaly connects two large-scale conductors—Pacific seawater and deep magma reservoir beneath a volcanic belt. Between two so different conductors, an unstable transition zone sensitive to changes of stress before strong EQs can be expected

Поздняя отсроченная нейтропения, индуцированная анти-В-клеточной терапией ритуксимабом, у пациентов с АНЦА-ассоциированными системными васкулитами

In the last decade, anti-neutrophil cytoplasmic antibodies (ANCA)-associated systemic vasculitis (SV) has been treated with the anti-B-cell drug, rituximab (RTM) both for induction and maintenance therapy. One of the problems of the treatment with RTM in patients with ANCA-SV is the risk of late-onset neutropenia (LON), mechanisms of development of which have not been studied enough yet.Objective: to evaluate the incidence and outcomes of LON in patients with ANCA-SV treated with RTM. Patients and methods. A retrospective analysis of the register of 140 patients with ANCA-SV who received RTM treatment at the V.A. Nasonova Research Institute of Rheumatology from 2009 to 2021 years. The median duration of RTM treatment was 49 (6–121) months, the median of the total RTM dose was 3.5 (0.5–9.5) grams. The duration of follow-up exceeded 6 months after the first administration of RTM.Results and discussion. LON was detected in 16 (11.4%) patients, of which 6 suffered from Wegener's granulomatosis with polyangiitis (GPA), 4 – microscopic polyangiitis (MPA), 4 – Churg-Strauss eosinophilic granulomatosis with polyangiitis (EGPA) and 2 – undifferentiated ANCA-SV. In 8 (50%) out of 16 patients, LON developed within 2 months after the 1st course of RTM, in the remaining 8 patients, on average, after 10 (4– 15.5) months. A lethal outcome was documented in 5 (31.2%) of 16 cases of LON (1 with MPA, 3 with GPA, and 1 with EGPA) on average 2 (1.5–9) months after the 1st course of RTM, at the same time, in 4 patients LON was complicated by pneumonia, including 2 with septic shock, in another 1 case LON was combined with the development of acute myocardial infarction and progression of chronic renal failure. Overall mortality among 140 patients with ANCA-SV treated with RTM was 11.4%, while in cases with a fatal outcome, the frequency of LON reached 31.2%.Conclusion. Thus, LON induced by RTM is a common (11%) and clinically significant consequence of B-cell depletion in patients with ANCA-SV, in every 5th case it is complicated by serious infections (including sepsis in 13%) and accounts for a significant proportion in the structure of lethal outcomes (31.2%).Patients treated with RTM require careful monitoring of absolute neutrophil count both during the first months after initiation of anti-B-cell therapy and thereafter. In the combined administration of RTM with cytotoxic drugs (primarily cyclophosphamide) in patients with ANCA-SV, it is necessary to consider the risk of LON developing, secondary immunodeficiency, and infectious complications. During the coronavirus pandemic, one should remember that treatment with interleukin 6 inhibitors used in severe COVID-19 can also be accompanied by neutropenia and requires careful dynamic monitoring of the absolute number of neutrophils in patients with ANCA-SV treated with RTM. It is necessary to inform both patients and physicians of the risk of LON development during the treatment of RTM in ANCA-SV and other rheumatic diseases.В последнее десятилетие при системных васкулитах (СВ), ассоциированных с антинейтрофильными цитоплазматическими антителами (АНЦА), в качестве индукционной и поддерживающей терапии применяют анти-В-клеточный препарат ритуксимаб (РТМ). Одной из проблем лечения РТМ пациентов с АНЦА-СВ является риск поздней отсроченной нейтропении (ПОН), механизмы развития которой до настоящего времени изучены недостаточно.Цель исследования – оценить частоту и исходы ПОН у пациентов с АНЦА-СВ, получающих лечение РТМ. Пациенты и методы. Был поведен ретроспективный анализ регистра 140 пациентов с АНЦА-СВ, получавших терапию РТМ в ФГБНУ «Научно-исследовательский институт ревматологии им. В.А. Насоновой» с 2009 по 2021 г. Медиана продолжительности лечения РТМ составила 49 (6–121) мес, медиана суммарной дозы РТМ – 3,5 (0,5–9,5) г. Длительность наблюдения превышала 6 мес после 1-го введения РТМ.Результаты и обсуждение. ПОН выявлена у 16 (11,4%) больных, из них 6 страдали гранулематозом с полиангиитом Вегенера (ГПА), 4 – микроскопическим полиангиитом (МПА), 4 – эозинофильным гранулематозом с полиангиитом Черджа–Стросс (ЭГПА) и 2 – недифференцированным АНЦА-СВ. У 8 (50%) из 16 пациентов ПОН развилась в течение 2 мес после 1-го курса РТМ, у остальных 8 – в среднем через 10 (4–15,5) мес. Летальный исход отмечен в 5 (31,2%) из 16 случаев ПОН (1 – с МПА, 3 – с ГПА и 1 – с ЭГПА) в среднем через 2 (1,5–9) мес после 1-го курса РТМ, при этом у 4 пациентов ПОН осложнилась пневмонией, в том числе у 2 с септическим шоком, еще в 1 наблюдении ПОН сочеталась с развитием острого инфаркта миокарда и прогрессированием хронической почечной недостаточности. Общая летальность среди 140 пациентов с АНЦА-СВ, получавших терапию РТМ, составила 11,4%, при этом среди случаев с летальным исходом частота ПОН достигала 31,2%.Заключение. Таким образом, ПОН, индуцированная РТМ, является распространенным (11%) и клинически значимым следствием В-клеточной деплеции у пациентов с АНЦА-СВ, в каждом 5-м случае осложняется серьезными инфекциями (включая сепсис у 13%) и составляет значительную долю в структуре летальных исходов (31,2%).Пациенты, получающие лечение РТМ, требуют тщательного мониторинга абсолютного числа нейтрофилов как в первые месяцы после начала анти-В-клеточной терапии, так и в дальнейшем. При сочетанном назначении РТМ с цитостатиками (в первую очередь с циклофосфаном) у больных АНЦА-СВ необходимо учитывать риск развития ПОН, вторичного иммунодефицитного состояния, инфекционных осложнений. В период пандемии коронавирусной инфекции следует помнить, что лечение ингибиторами интерлейкина 6, применяемыми при COVID-19 тяжелого течения, также может сопровождаться нейтропенией и требует тщательного динамического контроля абсолютного числа нейтрофилов у пациентов с АНЦА-СВ, получавших РТМ. Необходимо информировать как пациентов, так и врачей о риске развития ПОН на фоне лечения РТМ при АНЦА-СВ и других ревматических заболеваниях

Finite-Range Gravity and Its Role in Gravitational Waves, Black Holes and Cosmology

Theoretical considerations of fundamental physics, as well as certain cosmological observations, persistently point out to permissibility, and maybe necessity, of macroscopic modifications of the Einstein general relativity. The field-theoretical formulation of general relativity helped us to identify the phenomenological seeds of such modifications. They take place in the form of very specific mass-terms, which appear in addition to the field-theoretical analog of the usual Hilbert-Einstein Lagrangian. We interpret the added terms as masses of the spin-2 and spin-0 gravitons. The arising finite-range gravity is a fully consistent theory, which smoothly approaches general relativity in the massless limit, that is, when both masses tend to zero and the range of gravity tends to infinity. We show that all local weak-field predictions of the theory are in perfect agreement with the available experimental data. However, some other conclusions of the non-linear massive theory are in a striking contrast with those of general relativity. We show in detail how the arbitrarily small mass-terms eliminate the black hole event horizon and replace a permanent power-law expansion of a homogeneous isotropic universe with an oscillatory behaviour. One variant of the theory allows the cosmological scale factor to exhibit an `accelerated expansion'instead of slowing down to a regular maximum of expansion. We show in detail why the traditional, Fierz-Pauli, massive gravity is in conflict not only with the static-field experiments but also with the available indirect gravitational-wave observations. At the same time, we demonstrate the incorrectness of the widely held belief that the non-Fierz-Pauli theories possess `negative energies' and `instabilities'.Comment: 56 pages including 11 figures; significant modifications; in particular, we demonstrate the incorrectness of the widely held belief that the non-Fierz-Pauli theories should suffer from negative energies and instabilities; to appear in Int. J. Mod. Phys.

Data Driven Control of Vagus Nerve Stimulation for the Cardiovascular System: An in Silico Computational Study

Vagus nerve stimulation is an emerging therapy that seeks to offset pathological conditions by electrically stimulating the vagus nerve through cuff electrodes, where an electrical pulse is defined by several parameters such as pulse amplitude, pulse width, and pulse frequency. Currently, vagus nerve stimulation is under investigation for the treatment of heart failure, cardiac arrhythmia and hypertension. Through several clinical trials that sought to assess vagus nerve stimulation for the treatment of heart failure, stimulation parameters were determined heuristically and the results were inconclusive, which has led to the suggestion of using a closed-loop approach to optimize the stimulation parameters. A recent investigation has demonstrated highly specific control of cardiovascular physiology by selectively activating different fibers in the vagus nerve. When multiple locations and multiple stimulation parameters are considered for optimization, the design of closed-loop control becomes considerably more challenging. To address this challenge, we investigated a data-driven control scheme for both modeling and controlling the rat cardiovascular system. Using an existing in silico physiological model of a rat heart to generate synthetic input-output data, we trained a long short-term memory network (LSTM) to map the effect of stimulation on the heart rate and blood pressure. The trained LSTM was utilized in a model predictive control framework to optimize the vagus nerve stimulation parameters for set point tracking of the heart rate and the blood pressure in closed-loop simulations. Additionally, we altered the underlying in silico physiological model to consider intra-patient variability, and diseased dynamics from increased sympathetic tone in designing closed-loop VNS strategies. Throughout the different simulation scenarios, we leveraged the design of the controller to demonstrate alternative clinical objectives. Our results show that the controller can optimize stimulation parameters to achieve set-point tracking with nominal offset while remaining computationally efficient. Furthermore, we show a controller formulation that compensates for mismatch due to intra-patient variabilty, and diseased dynamics. This study demonstrates the first application and a proof-of-concept for using a purely data-driven approach for the optimization of vagus nerve stimulation parameters in closed-loop control of the cardiovascular system