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Bone fracture is a growing public health burden and there is a clinical need for non-invasive therapies to aid in the fracture healing process. Previous studies have demonstrated the utility of electromagnetic (EM) fields in promoting bone repair; however, its underlying mechanism of action is unclear. Interestingly, there is a growing body of literature describing positive effects of an EM field on mitochondria. In our own work, we have previously demonstrated that differentiation of osteoprogenitors into osteoblasts involves activation of mitochondrial oxidative phosphorylation (OxPhos). Therefore, it was reasonable to propose that EM field therapy exerts bone anabolic effects via stimulation of mitochondrial OxPhos. In this study, we show that application of a low intensity constant EM field source on osteogenic cells in vitro resulted in increased mitochondrial membrane potential and respiratory complex I activity and induced osteogenic differentiation. In the presence of mitochondrial inhibitor antimycin A, the osteoinductive effect was reversed, confirming that this effect was mediated via increased OxPhos activity. Using a mouse tibial bone fracture model in vivo, we show that application of a low intensity constant EM field source enhanced fracture repair via improved biomechanical properties and increased callus bone mineralization. Overall, this study provides supporting evidence that EM field therapy promotes bone fracture repair through mitochondrial OxPhos activation.

Models of the Earth climate system, along with the physical components of the climate (atmosphere, ocean, sea ice, active land layer), contain modules for describing (bio)geochemical processes in the Earth system, as well as the socio-economic processes in some cases. At the top of the hierarchy of such models one can see general-circulation models which are able to represent each of the considered components in detail, but are characterized by high computational cost. The simplest models of the Earth climate system are the energy-balance models and radiative-convective models characterized by low spatial resolution and allowance for only a small number of the most important climate-forming processes. Nevertheless, these models are characterized by a number of advantages, primarily, simple and understandable physics. Moreover, radiative-convective models are useful for studying a number of the processes allowed for in general-circulation models and tuning appropriate modules. In addition, there is a class of models of the Earth climate system of intermediate complexity, which take into account most of the processes presented in the general-circulation models (and sometimes the processes unaccounted for in the latters), but with a number of simplifications. The advantage of this class is related to an opportunity of integrating the model for the periods of tens of thousands years or even more. The review deals with all these classes of models with discussions of their features, including the conservation laws explicitly taken into account in them, as well as the classes of problems to which it is advisable to apply the models of the Earth climate system of different types. Additionally, the projects for comparing the models of the Earth climate system in which models of different classes are used simultaneously are discussed.

It is shown that various sensors are used to ensure air traffic control in civil aviation, namely: primary and secondary radars, multilateration surveillance systems, automatic dependent surveillance systems of broadcast and contract types, multistatic radars. Based on the analysis of the main disadvantages of the considered systems, it was concluded that the use of multilateration aircraft surveillance systems (MLAT) is promising. The need to improve the reliability of MLAT is noted. The work proposes a method of structural and informational redundancy of MLAT based on the introduction of an additional receiver into its design. It allows to measure the distance to the aircraft using the energy method. The analysis of increasing the reliability of MLAT at various redundancy rates is carried out.

It is shown that a significant disadvantage of the broadcast-type automatic dependent surveillance system (ADS-B) used to solve the problem of aviation surveillance is its vulnerability to spoofing attempts. To eliminate this disadvantage, it is currently proposed to use the monitoring of ADS-B data using multilateration aviation surveillance systems (MLAT). The work shows the necessity of MLAT modernization to ensure a reliable solution to the problem of aviation surveillance in the event of failure of one or more reception points. To do this, it is proposed to use hybrid methods for assessing the coordinates of an aircraft. It can reduce the number of minimum required receiving positions due to the structural and informational redundancy of the aviation surveillance system. Structures (scenarios) of hybrid multi-position aviation surveillance systems and algorithms for processing their measurements have been developed. The algorithms ensure an increase in the reliability of the formation of estimates of aircraft coordinates.

Polar van der Waals chalcogenophosphates exhibit unique properties, such as negative electrostriction and multi-well ferrielectricity, and enable combining dielectric and 2D electronic materials. Using low temperature piezoresponse force microscopy, we revealed coexistence of piezoelectric and non-piezoelectric phases in CuInP 2 Se 6 , forming unusual domain walls with enhanced piezoelectric response. From systematic imaging experiments we have inferred the formation of a partially polarized antiferroelectric state, with inclusions of structurally distinct ferrielectric domains enclosed by the corresponding phase boundaries. The assignment is strongly supported by optical spectroscopies and density-functional-theory calculations. Enhanced piezoresponse at the ferrielectric/antiferroelectric phase boundary and the ability to manipulate this entity with electric field on the nanoscale expand the existing phenomenology of functional domain walls. At the same time, phase-coexistence in chalcogenophosphates may lead to rational strategies for incorporation of ferroic functionality into van der Waals heterostructures, with stronger resilience toward detrimental size-effects. Domain walls in van der Waals layered ferrielectric CuInP 2 Se 6 exhibit piezoelectric response. This striking departure from traditional ferroelectric behavior is ascribed to a partially polarized antiferroelectric state, where the domain wall separates coexisting regions of ferrielectric and antiferroelectric phases.

The physics of ferroelectric domain walls is explored using the Bayesian inference analysis of atomically resolved STEM data. We demonstrate that domain wall profile shapes are ultimately sensitive to the nature of the order parameter in the material, including the functional form of Ginzburg-Landau-Devonshire expansion, and numerical value of the corresponding parameters. The preexisting materials knowledge naturally folds in the Bayesian framework in the form of prior distributions, with the different order parameters forming competing (or hierarchical) models. Here, we explore the physics of the ferroelectric domain walls in BiFeO 3 using this method, and derive the posterior estimates of relevant parameters. More generally, this inference approach both allows learning materials physics from experimental data with associated uncertainty quantification, and establishing guidelines for instrumental development answering questions on what resolution and information limits are necessary for reliable observation of specific physical mechanisms of interest. Ferroelectric domain wall profiles can be modeled by phenomenological Ginzburg-Landau theory, with different candidate models and parameters. Here, the authors solve the problem of model selection by developing a Bayesian inference framework allowing for uncertainty quantification and apply it to atomically resolved images of walls. This analysis can also predict the level of microscope performance needed to detect specific physical phenomena.

The main role in the current climate change is played by anthropogenic forcings, primarily anthropogenic emissions of greenhouse gases and aerosols. On the global scale, the response of the Earth system to these forcings is close to linear. In particular, it depends mostly on the magnitude of such forcings and only weakly on their nature and spatial localization. However, even with relatively small (in absolute value) external forcings, the response of the characteristics of the Earth system can be essentially nonlinear with the manifestation of tipping points, upon transition through which the behavior of the Earth’s climate changes qualitatively. Examples are given for linear and nonlinear mechanisms of the climate response to external forcings.

Topological defects in ferroic materials are attracting much attention both as a playground of unique physical phenomena and for potential applications in reconfigurable electronic devices. Here, we explore electronic transport at artificially created ferroelectric vortices in BiFeO 3 thin films. The creation of one-dimensional conductive channels activated at voltages as low as 1 V is demonstrated. We study the electronic as well as the static and dynamic polarization structure of several topological defects using a combination of first-principles and phase-field modelling. The modelling predicts that the core structure can undergo a reversible transformation into a metastable twist structure, extending charged domain walls segments through the film thickness. The vortex core is therefore a dynamic conductor controlled by the coupled response of polarization and electron–mobile-vacancy subsystems with external bias. This controlled creation of conductive one-dimensional channels suggests a pathway for the design and implementation of integrated oxide electronic devices based on domain patterning. The controlled creation of one-dimensional conductive channels at the cores of topological defects in the multiferroic material BiFeO 3 demonstrates that such defects can drive metal–insulator phase transitions, and might provide a route towards high-density information storage.

Wetlands are the world's largest natural source of methane, a powerful greenhouse gas. The strong sensitivity of methane emissions to environmental factors such as soil temperature and moisture has led to concerns about potential positive feedbacks to climate change. This risk is particularly relevant at high latitudes, which have experienced pronounced warming and where thawing permafrost could potentially liberate large amounts of labile carbon over the next 100 years. However, global models disagree as to the magnitude and spatial distribution of emissions, due to uncertainties in wetland area and emissions per unit area and a scarcity of in situ observations. Recent intensive field campaigns across the West Siberian Lowland (WSL) make this an ideal region over which to assess the performance of large-scale process-based wetland models in a high-latitude environment. Here we present the results of a follow-up to the Wetland and Wetland CH4 Intercomparison of Models Project (WETCHIMP), focused on the West Siberian Lowland (WETCHIMP-WSL). We assessed 21 models and 5 inversions over this domain in terms of total CH4 emissions, simulated wetland areas, and CH4 fluxes per unit wetland area and compared these results to an intensive in situ CH4 flux data set, several wetland maps, and two satellite surface water products. We found that (a) despite the large scatter of individual estimates, 12-year mean estimates of annual total emissions over the WSL from forward models (5.34 ± 0.54 Tg CH4 yr−1), inversions (6.06 ± 1.22 Tg CH4 yr−1), and in situ observations (3.91 ± 1.29 Tg CH4 yr−1) largely agreed; (b) forward models using surface water products alone to estimate wetland areas suffered from severe biases in CH4 emissions; (c) the interannual time series of models that lacked either soil thermal physics appropriate to the high latitudes or realistic emissions from unsaturated peatlands tended to be dominated by a single environmental driver (inundation or air temperature), unlike those of inversions and more sophisticated forward models; (d) differences in biogeochemical schemes across models had relatively smaller influence over performance; and (e) multiyear or multidecade observational records are crucial for evaluating models' responses to long-term climate change.

Structural ordering in the concentrated magnetic colloids containing 50 × 5 nm hard magnetic disc-like SrFe 12 O 19 nanoparticles was investigated by cryogenic scanning electron microscopy, optical microscopy, magnetic measurements, and small-angle X-ray scattering. It was revealed that macroscopically homogeneous magnetic liquid consists of dynamic threads of stacked nanoparticles. The threads align into quasiperiodic arrays with the distances between individual threads of a few micrometers. They also can form pseudodomain structures with ~ 90° domain boundaries realized through T-type thread interconnects. The effects of magnetic attraction and electrostatic repulsion on the equilibrium interplatelet distance in the threads were studied. It was demonstrated that this distance can be tuned by the control of the particles charge and electric double layer screening from Stern layer thickness (~ 1 nm) to tens of nanometers. It was shown that the permanent magnetic field is not able to cause any structural changes in the ordered magnetic liquid phase, while alternating field draws particles apart by their vibrations. External variation of interparticle distance up to 6% was achieved using an alternating magnetic field of low intensity. Experimental data were complemented by the theoretical models of screened electrostatic interactions between spherical and platelike magnetic particles. The last model provides good predictive power and correlates with the experimental data. The stabilization energy of the condensed phase in the order of 1–10 k B T was derived from the model. An approach allows controlling of an equilibrium interparticle distance and interparticle distance distribution by adjusting the magnetization and surface charge of the particles as well as the ionic strength of the solvent.