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Наведено огляд існуючих конструкцій приймально-передавальних модулів (ППМ) для активних фазованих антенних решіток. Показана тенденція розвитку СВЧ елементної бази для побудови більш потужних ППМ. Розглянуто особливості застосовуваних і перспективних систем охолодження. Показана можливість використання теплових труб в системах охолодження ППМ. The report reviews the existing designs of transmit/receive modules (ТRMs) for active phased antenna arrays (APAA). The trend in the development of the super-high-frequency hardware components for building more powerful TRMs is shown. The features of the currently used and prospective cooling systems are examined. The possibility of using heat pipes in the cooling systems of the TRMs is demonstrated. Keywords: APAA, transmit/receive module, cooling system, heat pipe. Приведен обзор существующих конструкций приемопередающих модулей (ППМ) для активных фази-рованных антенных решеток. Показана тенденция развития СВЧ элементой базы для построения более мощных ППМ. Рассморены особенности применяемых и перспективных систем охлаждения. Показана возможность использования тепловых труб в системах охлаждения ППМ.

© 2017 American Chemical Society.The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic.

© 2017 John Wiley & Sons Ltd. Signal transducers and activators of transcription (STATs) are key molecular determinants of T-cell fate and effector function. Several inflammatory diseases are characterized by an altered balance of T-cell phenotypes and cytokine secretion. STATs, therefore, represent viable therapeutic targets in numerous pathologies. However, the underlying mechanisms by which the same STAT proteins regulate both the development of different T-cell phenotypes and their plasticity during changes in extracellular conditions remain unclear. In this study, we investigated the STAT-mediated regulation of T-cell phenotype formation and plasticity using mathematical modelling and experimental data for intracellular STAT signalling proteins. The close fit of our model predictions to the experimental data allows us to propose a potential mechanism for T-cell switching. According to this mechanism, T-cell phenotype switching is the result of the relative redistribution of STAT dimer complexes caused by the extracellular cytokine-dependent STAT competition effects. The developed model predicts that the balance between the intracellular STAT species defines the amount of the produced cytokines and thereby T-cell phenotypes. The model predictions are consistent with the experimentally observed interferon-γ to interleukin-10 switching that regulates human T helper type 1/type 1 regulatory T-cell responses. The proposed model is applicable to a number of STAT signalling circuits.

Summary. The article presents the results of the evaluation of different framework design solutions of superstructure floors of low-rise residential buildings. Purpose. Assessment of the effectiveness of pipe-concrete application for increase the number of storeys of low-rise residential buildings on the basis of the analysis of structural variants of resource consumption for variants of structural solutions of superstructure floors. Methods. A method of framework superstructure for additional floors of the reconstructed low-rise residential building without relocation of occupants has been proposed. The method consists in the organization of metal portal frames built along the walls of the existing building on the independent foundations, on which rest the girders, beams, ties and other structures taking the stresses of the superstructure. Results. Framework design solution for floors superstructure of low-rise residential building has been developed. The variants of framework with reinforced concrete, metal frame and framework of the pipe-concrete elements were analyzed. Based on the analysis of the stress-strain state of structural elements of framework, a comparative analysis of the consumption of materials for its construction was made. Scientific novelty. On the basis of the research it was found that the pipe-concrete structures meet the requirements of a rational joint work of steel and concrete. Practical value. The possibility of increasing the number of storeys of low-rise residential buildings with their reconstruction without the relocation of occupants., Аннотация. Представлены результаты оценки вариантов конструктивного решения каркаса надстройки этажей малоэтажного жилого здания. Цель работы. Оценка эффективности применения трубобетона для увеличения этажности малоэтажных жилых зданий на основе анализа ресурсоёмкости вариантов конструктивных решений каркаса надстройки этажей. Методика. Предложен метод надстройки каркаса дополнительных этажей реконструируемого малоэтажного жилого здания без отселения жильцов. Суть метода заключается в устройстве вдоль стен существующего здания на самостоятельных фундаментах металлических портальных рам каркаса, на которые опираются фермы, ригели, связи и другие конструкции, воспринимающие нагрузки от возводимой надстройки. Результаты. Разработано конструктивное решение каркаса надстройки этажей малоэтажного жилого здания. Рассмотрены варианты каркаса с применением монолитного железобетона, металлического каркаса и каркаса из трубобетонных элементов. На основе анализа напряженно-деформированного состояния элементов конструкций каркаса выполнен подбор сечений и сравнительный анализ расхода материалов на его возведение. Научная новизна. На основе выполненных исследований установлено, что трубобетонные конструкции отвечают требованиям рациональной совместной работы стали и бетона. Практическая значимость. Возможность увеличения этажности малоэтажных жилых зданий при их реконструкции без отселения жильцов., Анотація. Наведено результати оцінювання варіантів конструктивного рішення каркаса надбудови поверхів малоповерхового житлового будинку. Мета роботи. Оцінювання ефективності застосування трубобетону для збільшення поверховості малоповерхових житлових будинків на основі аналізу ресурсоємності варіантів конструктивних рішень каркаса надбудови поверхів. Методика. Запропоновано метод надбудови каркаса додаткових поверхів малоповерхового житлового будинку, що реконструюється без відселення мешканців. Суть методу полягає в улаштуванні уздовж стін існуючої будівлі на самостійних фундаментах металевих портальних рам каркаса, на які спираються ферми, ригелі, в'язі та інші конструкції, що приймають навантаження від конструкції надбудови. Результати. Розроблено конструктивне рішення каркаса надбудови поверхів малоповерхового житлового будинку. Розглянуто варіанти каркаса із застосуванням монолітного залізобетону, металевого каркаса і каркаса з трубобетонних елементів. На основі аналізу напружено-деформованого стану елементів конструкцій каркаса виконано підбір перерізів і порівняльний аналіз витрат матеріалів на його зведення. Наукова новизна. На основі виконаних досліджень установлено, що трубобетонні конструкції відповідають вимогам раціональної спільної роботи сталі і бетону. Практична значимість. Можливість збільшення поверховості малоповерхових житлових будинків у разі їх реконструкції без відселення мешканців.

It is known that most enzyme-facilitated reactions are highly temperature dependent processes. In general, the temperature coefficient, Q10, of a simple reaction reaches 2.0-3.0. Nevertheless, some enzyme-controlled processes have much lower Q10 (about 1.0), which implies that the process is almost temperature independent, even if individual reactions involved in the process are themselves highly temperature dependent. In this work, we investigate a possible mechanism for this apparent temperature compensation: simple mathematical models are used to study how varying types of enzyme reactions are affected by temperature. We show that some bienzyme-controlled processes may be almost temperature independent if the modules involved in the reaction have similar temperature dependencies, even if individually, these modules are strongly temperature dependent. Further, we show that in non-reversible enzyme chains the stationary concentrations of metabolites are dependent only on the relationship between the temperature dependencies of the first and last modules, whilst in reversible reactions, there is a dependence on every module. Our findings suggest a mechanism by which the metabolic processes taking place within living organisms may be regulated, despite strong variation in temperature.

© 2016 Salakhieva et al.Background: Second messengers, such as calcium, regulate the activity of multisite binding proteins in a concentration-dependent manner. For example, calcium binding has been shown to induce conformational transitions in the calcium-dependent protein calmodulin, under steady state conditions. However, intracellular concentrations of these second messengers are often subject to rapid change. The mechanisms underlying dynamic ligand-dependent regulation of multisite proteins require further elucidation. Results: In this study, a computational analysis of multisite protein kinetics in response to rapid changes in ligand concentrations is presented. Two major physiological scenarios are investigated: i) Ligand concentration is abundant and the ligand-multisite protein binding does not affect free ligand concentration, ii) Ligand concentration is of the same order of magnitude as the interacting multisite protein concentration and does not change. Therefore, buffering effects significantly influence the amounts of free ligands. For each of these scenarios the influence of the number of binding sites, the temporal effects on intermediate apo- and fully saturated conformations and the multisite regulatory effects on target proteins are investigated. Conclusions: The developed models allow for a novel and accurate interpretation of concentration and pressure jump-dependent kinetic experiments. The presented model makes predictions for the temporal distribution of multisite protein conformations in complex with variable numbers of ligands. Furthermore, it derives the characteristic time and the dynamics for the kinetic responses elicited by a ligand concentration change as a function of ligand concentration and the number of ligand binding sites. Effector proteins regulated by multisite ligand binding are shown to depend on ligand concentration in a highly nonlinear fashion.

© 2015 The Authors. Human erythrocytes are highly specialized enucleate cells that are involved in providing efficient gas transport. Erythrocytes have been extensively studied both experimentally and by mathematical modeling in recent years. However, understanding of how aggregation and deformability are regulated is limited. These properties of the erythrocyte are essential for the physiological functioning of the cell. In this work, we propose a novel mathematical model of the molecular system that controls the aggregation and deformability of the erythrocyte. This model is based on the experimental results of previously published studies. Our model suggests fundamentally new mechanisms that regulate aggregation and deformability in a latch-like manner. The results of this work could be used as a general explanation of how the erythrocytes regulate their aggregation and deformability, and are essential in understanding erythrocyte disorders and aging.

В статье обобщены сведения о факторах, влияющих на выбор глубины заложения и конструкции фундамента, изложены практические рекомендации для проектирования рациональных конструкций фундаментов малоэтажных зданий. Приведенные сведения и рекомендации могут быть полезными для строительства индивидуальных экологических зданий., У статті узагальнені відомості про фактори, що впливають на вибір глибини закладення і конструкції фундаменту, викладені практичні рекомендації для проектування раціональних конструкцій фундаментів малоповерхових будівель. Наведені відомості і рекомендації можуть бути корисними для будівництва індивідуальних екологічних будівель.

© 2014 Sadreev et al. Phosphorylation is a fundamental biochemical reaction that modulates protein activity in cells. While a single phosphorylation event is relatively easy to understand, multisite phosphorylation requires systems approaches for deeper elucidation of the underlying molecular mechanisms. In this paper we develop a mechanistic model for single- and multisite phosphorylation. The proposed model is compared with previously reported studies. We compare the predictions of our model with experiments published in the literature in the context of inflammatory signaling events in order to provide a mechanistic description of the multisite phosphorylation-mediated regulation of Signal Transducer and Activator of Transcription 3 (STAT3) and Interferon Regulatory Factor 5 (IRF-5) proteins. The presented model makes crucial predictions for transcription factor phosphorylation events in the immune system. The model proposes potential mechanisms for T cell phenotype switching and production of cytokines. This study also provides a generic framework for the better understanding of a large number of multisite phosphorylation-regulated biochemical circuits.

Under the condition of microelectrode recording and fluorescence microscopy with dye FM 1-43 the research of exo-/endocytosis of synaptic vesicles in motor nerve terminals (NT) of frog cutaneous pectoris and white mice diaphragm muscles during high frequency stimulation (20 imp/s) was carried out. A mathematical modeling allowed us to conclude that the obtained experimental data can be explained in the following framework. Three pools of synaptic vesicles are involved in neurotransmitter release in the frog motor NT. Recovery of these pools is provided by endocytosis of two types: fast endocytosis with limited capacity and slow endocytosis. Fast-reconstructing vesicles refill the mobilization pool and slow endocytosis recovers the reserve pool. Our modeling investigation has revealed in frog NT independent recruiting of reserve and mobilization pools to the neurotransmitter secretion, i. e. this pools work concurrently. Experimental data, obtained on mice preparations, are well described with the framework of two-pools model including single type of endocytosis (fast endocytosis). © 2012 Pleiades Publishing, Ltd.

The article substantiates the expediency of obtaining brick rubble from the rubble of walls formed during the demolition of emergency residential buildings. The formulas for calculating the labor intensity and cost of 1 m3 of concrete mix on brick gravel are substantiated., В статье обосновывается целесообразность получения кирпичного щебня из обломков стен, образующихся при сносе аварийных жилых зданий.Приведены формулы для расчета трудоемкости и стоимости 1 м3 бетонной смеси на кирпичном щебне., У статье обосновується цілесообразность отримання кирпичного щебня з обломків стен, що утворюються при збиранні аварийних жирних приміщень.

Systems Biology approaches to drug discovery largely focus on the increasing understanding of intracellular and cellular circuits, by computational representation of a molecular system followed by parameter validation against experimental data. This chapter outlines a universal approach to systems biology that allows the linking of intracellular molecular machinery and cellular activity. This procedure is achieved by applying mathematical modeling to molecular modules of a cell in the light of systems biology techniques. © 2010 Springer Science+Business Media, LLC.

Inflammation is characterized by altered cytokine levels produced by cell populations in a highly interdependent manner. To elucidate the mechanism of an inflammatory reaction, we have developed a mathematical model for immune cell interactions via the specific, dose-dependent cytokine production rates of cell populations. The model describes the criteria required for normal and pathological immune system responses and suggests that alterations in the cytokine production rates can lead to various stable levels which manifest themselves in different disease phenotypes. The model predicts that pairs of interacting immune cell populations can maintain homeostatic and elevated extracellular cytokine concentration levels, enabling them to operate as an immune system switch. The concept described here is developed in the context of psoriasis, an immune-mediated disease, but it can also offer mechanistic insights into other inflammatory pathologies as it explains how interactions between immune cell populations can lead to disease phenotypes. © 2010 Valeyev et al.

Under conditions of starvation, Dictyostelium cells begin a programme of development during which they aggregate to form a multicellular structure by chemotaxis, guided by propagating waves of cyclic AMP that are relayed robustly from cell to cell. In this paper, we develop and analyse a new model for the intracellular and extracellular cAMP dependent processes that regulate Dictyostelium migration. The model allows, for the first time, a quantitative analysis of the dynamic interactions between calcium, IP3 and G protein-dependent modules that are shown to be key to the generation of robust cAMP oscillations in Dictyostelium cells. The model provides a mechanistic explanation for the transient increase in cytosolic free Ca2+ concentration seen in recent experiments with the application of the calmodulin inhibitor calmidazolium (R24571) to Dictyostelium cells, and also allows elucidation of the effects of varying both the conductivity of stretch-activated channels and the concentration of external phosphodiesterase on the oscillatory regime of an individual cell. A rigorous analysis of the robustness of the new model shows that interactions between the different modules significantly reduce the sensitivity of the resulting cAMP oscillations to variations in the kinetics of different Dictyostelium cells, an essential requirement for the generation of the spatially and temporally synchronised chemoattractant cAMP waves that guide Dictyostelium aggregation. © The Royal Society of Chemistry 2009.

Cyclic adenosine monophosphate and cyclic guanosine monophosphate are universal intracellular messengers whose concentrations are regulated by molecular networks comprised of different isoforms of the synthases adenylate cyclase or guanylate cyclase and the phosphodiesterases which degrade these compounds. In this paper, we employ a systems biology approach to develop mathematical models of these networks that, for the first time, take into account the different biochemical properties of the isoforms involved. To investigate the mechanisms underlying the joint regulation of cAMP and cGMP, we apply our models to analyse the regulation of cilia beat frequency in Paramecium by Ca2+. Based on our analysis of these models, we propose that the diversity of isoform combinations that occurs in living cells provides an explanation for the huge variety of intracellular processes that are dependent on these networks. The inclusion of both G-protein receptor and Ca 2+-dependent regulation of AC in our models allows us to propose a new explanation for the switching properties of G-protein subunits involved in nucleotide regulation. Analysis of the models suggests that, depending on whether the G-protein subunit is bound to AC, Ca2+ can either activate or inhibit AC in a concentration-dependent manner. The resulting analysis provides an explanation for previous experimental results that showed that alterations in Ca2+ concentrations can either increase or decrease cilia beat frequency over particular Ca2+ concentration ranges. © The Royal Society of Chemistry.

Protein-protein or protein-ion interactions with multisite proteins are essential to the regulation of intracellular and extracellular events. There is, however, limited understanding of how ligand-multisite protein interactions selectively regulate the activities of multiple protein targets. In this paper, we focus on the important calcium (Ca2+) binding protein calmodulin (CaM), which has four Ca2+ ion binding sites and regulates the activity of over 30 other proteins. Recent progress in structural studies has led to significant improvements in the understanding of Ca2+-CaM- dependent regulation mechanisms. However, no quantitative model is currently available that can fully explain how the structural diversity of protein interaction surfaces leads to selective activation of protein targets. In this paper, we analyze the multisite protein-ligand binding mechanism using mathematical modelling and experimental data for Ca2+-CaM-dependent protein targets. Our study suggests a potential mechanism for selective and differential activation of Ca2+-CaM targets by the same CaM molecules, which are involved in a variety of intracellular functions. The close agreement between model predictions and experimental dose-response curves for CaM targets available in the literature suggests that such activation is due to the selective activity of CaM conformations in complexes with variable numbers of Ca2+ ions. Although the paper focuses on the Ca2+-CaM pair as a particularly data rich example, the proposed model predictions are quite general and can easily be extended to other multisite proteins. The results of the study may therefore be proposed as a general explanation for multifunctional target regulation by multisite proteins. © The Royal Society of Chemistry.

A series of fulleropyrrolidine- and fulleropyrrolidinium-based donor-acceptor ensembles were tested in light of intrinsic reorganization energies for photoinduced electron transfer events. Among these complexes, the fulleropyrrolidinium ions are particularly well-suited for the role of an acceptor moiety. In fact, once reduced, fulleropyrrolidinium ions exhibit a zwitterionic character, due to the contemporary presence of a positive pyrrolidinium ion together with the fullerene radical ion. We demonstrate that this zwitterionic character of the acceptor plays a central role in improving acceleration of charge separation and deceleration of charge recombination. While the charge separation occurs with dynamics close to the top region of the Marcus parabola, the charge recombination rates are pushed deeply into the inverted region of the parabolic dependence. Overall, we determined reorganization energies (ì) for the fulleropyrrolidinium-based ensemble that are appreciably smaller than those seen for the fulleropyrrolidine-based analogue, while keeping the electronic coupling element constant (!). Remarkable is the oxygen effect on the zwitterionic fulleropyrrolidinium acceptorsnot seen on the fulleropyrrolidine acceptorsin the charge-separated radical pair.

Layer-by-layer (LBL) films of a fulleropyrrolidinium-androstane-ferrocene dyad revealed a surprisingly high level of intermolecular organization. In particular, in every adsorption layer, the films self-assemble into linear nanowire superstructures. Given the inherent intramolecular charge transfer performance of the dyads, such a film organization facilitates the charge diffusion from the photoactive centers to the electrodes, due to extensive interpenetration of the layers, which leads to multiple contacts between the fullerene-ferrocene nanowires.

A systemic study of the mechanisms of motor activity of paramecium was carried out. The movements of paramecium responding to various influences were photographed. The analysis of the data revealed the time dependences of the rate of movement, rate of rotation, and the radius and the pitch of the helix trajectory. Mathematical models of the membrane and a unit that transforms the calcium signal to programs of regulating the effectors were constructed. A system of equations for constructing the trajectory of movement was proposed. It is concluded that the biomolecular system that involves calmodulin, calmodulin-dependent ionic channels, adenylate cyclase, guanylate cyclase, phosphodiesterases, Ca2+-calmodulin, cAMP, cGMP-dependent protein kinases, and phosphoprotein phosphatases is capable of regulating motor reactions necessary for complex maneuvering of paramecium under various conditions.

A systemic study of the mechanisms of motor activity of paramecium was carried out. The movements of paramecium responding to various influences were photographed. The analysis of the data revealed the time dependences of the rate of movement, rate of rotation, and the radius and the pitch of the helix trajectory. Mathematical models of the membrane and a unit that transforms the calcium signal to programs of regulating the effectors were constructed. A system of equations for constructing the trajectory of movement was proposed. It is concluded that the biomolecular system that involves calmodulin, calmodulin-dependent ionic channels, adenylate cyclase, guanylate cyclase, phosphodiesterases, Ca(2+)-calmodulin, cAMP, cGMP-dependent protein kinases, and phosphoprotein phosphatases is capable of regulating motor reactions necessary for complex maneuvering of paramecium under various conditions.

A mathematical model of the dynamic behavior of phosphorylase kinase was devised. Based on the results obtained, the function of this protein is discussed. It is suggested that phosphorylase kinase doses in a cAMP-dependent manner additional portions of glucoso-1-phosphate, which the muscle cell receives in response to contraction.

A mathematical model of the dynamic behavior of phosphorylase kinase was devised. Based on the results obtained, the function of this protein is discussed. It is suggested that phosphorylase kinase doses in a cAMP-dependent manner additional portions of glucoso-l-phosphate, which the muscle cell receives in response to contraction.

The escape reaction in Paramecium caudatum has been investigated experimentally. A model of molecular system controlling cilia in cells during this reaction is described.

A physical approach is proposed to the description of the mechanism of motion of cilia based on the assumption of the importance of the hydrodynamic interactions within the cilium and the mechanism of synchronization of the beats in the metachronal waves is proposed. © 1992.

Summary In recent years, carbon dots, graphene quantum dots, and other carbon nanocolloids have attracted a mounting interest as readily available, non-toxic, and tailorable carbon-based nanomaterials. One of the most fascinating features of carbon nanocolloids is their luminescence, the origin of which remains a source of dispute. The lack of understanding of the optical properties of carbon nanocolloids hampers their use in technological, environmental, and biomedical processes. Here, we review the current knowledge of excited states in carbon nanocolloids and related properties, inviting researchers to embrace the complexity of carbon nanocolloids. We point to the fundamental problems associated with their structure, photophysics, and photochemistry and highlight multiple directions of current and future research of this exciting class of nanomaterials.

ANGEWANDTE CHEMIE, INT. ED. ENGL.