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To control the spin wave (SW) propagation, external energy sources such as magnetic fields, electric currents, or complex nanopatterning are used, which can be challenging at the deep nanoscale level. In this work, we overcome such limitations by demonstrating SW propagation in Pt/Co multilayers at a remanent state controlled by stripe domain patterns, using Brillouin light scattering and micromagnetic simulations. We show that parallel stripes with a periodicity around 100 nm exhibit reconfigurability, as the stripes can be rotated by applying the in-plane field without damaging their shape. This allows us to study SW propagation perpendicular and parallel to the stripes. We observe multimodal SW spectra—three bands in perpendicular and five in parallel geometry. Numerical results allow us to identify all observed modes and to explain the differences between two configurations by the unequal contribution of all three magnetization components in the SW dynamics. We find that the experimentally measured non-reciprocal dispersion (for the wavevector perpendicular to the stripes) is not the breaking of time-symmetry but the asymmetry in intensity of the measured signals of two different low-frequency modes, which is due to the inhomogeneous SW amplitude distribution over the multilayer thickness and the limited light penetration depth. Our results pave the way for easy reprogrammability and high energy efficiency in nanomagnonics. [ABSTRACT FROM AUTHOR]

Metal oxide core–shell fibrous nanostructures are promising gas-sensitive materials for the detection of a wide variety of both reducing and oxidizing gases. In these structures, two dissimilar materials with different work functions are brought into contact to form a coaxial heterojunction. The influence of the shell material on the transportation of the electric charge carriers along these structures is still not very well understood. This is due to homo-, hetero- and metal/semiconductor junctions, which make it difficult to investigate the electric charge transfer using direct current methods. However, in order to improve the gas-sensing properties of these complex structures, it is necessary to first establish a good understanding of the electric charge transfer in ambient air. In this article, we present an impedance spectroscopy study of networked SnO2/Ga2O3 core–shell nanobelts in ambient air. Tin dioxide nanobelts were grown directly on interdigitated gold electrodes, using the thermal sublimation method, via the vapor–liquid–solid (VLS) mechanism. Two forms of a gallium oxide shell of varying thickness were prepared via halide vapor-phase epitaxy (HVPE), and the impedance spectra were measured at 189–768 °C. The bulk resistance of the core–shell nanobelts was found to be reduced due to the formation of an electron accumulation layer in the SnO2 core. At temperatures above 530 °C, the thermal reduction of SnO2 and the associated decrease in its work function caused electrons to flow from the accumulation layer into the Ga2O3 shell, which resulted in an increase in bulk resistance. The junction resistance of said core–shell nanostructures was comparable to that of SnO2 nanobelts, as both structures are likely connected through existing SnO2/SnO2 homojunctions comprising thin amorphous layers. [ABSTRACT FROM AUTHOR]

Spin waves (SWs) are promising objects for signal processing and future quantum technologies due to their high microwave frequencies with corresponding nanoscale wavelengths. However, the nano‐wavelength SWs generated so far are limited to low frequencies. In the paper, using micromagnetic simulations, it is shown that a microwave‐pumped SW mode confined to the cavity of a thin film magnonic crystal (MC) can be used to generate waves at tens of GHz and wavelengths well below 50 nm. These multi‐frequency harmonics of the fundamental cavity mode are generated when the amplitude of the pumping microwave field exceeds a threshold, and their intensities then scale linearly with the field intensity. The frequency of the cavity mode is equal to the ferromagnetic resonance frequency of the planar ferromagnetic film, which overlaps with the magnonic bandgap, providing an efficient mechanism for confinement and magnetic field tunability. The effect reaches saturation when the microstrip feed line covers the entire cavity, making the system feasible for realization. [ABSTRACT FROM AUTHOR]

Extending the scope of the self-imaging phenomenon, traditionally associated with linear optics, to the domain of magnonics, this study presents the experimental demonstration and numerical analysis of spin-wave (SW) self-imaging in an in-plane magnetized yttrium iron garnet film. We explore this phenomenon using a setup in which a plane SW passes through a diffraction grating, and the resulting interference pattern is detected using Brillouin light scattering. We have varied the frequencies of the source dynamic magnetic field to discern the influence of the anisotropic dispersion relation and the caustic effect on the analyzed phenomenon. We found that at low frequencies and diffraction fields, the caustics determine the interference pattern. However, at large distances from the grating, when the waves of high diffraction order and number of slits contribute to the interference pattern, the self-imaging phenomenon and Talbot-like patterns are formed. This methodological approach not only sheds light on the behavior of SW interference under different conditions but also enhances our understanding of the SW self-imaging process in both isotropic and anisotropic media. [ABSTRACT FROM AUTHOR]

Study aim: Improvement of the upper extremities’ performance is one of the key aims in the rehabilitation process. In order to achieve high effectiveness of this process the amount of functional improvement achieved by a patient during the therapy needs to be assessed. The aim of this study was to obtain electromyographic (EMG) activity profiles of the upper extremity muscles during execution of simple tasks in healthy subjects. Additionally the ranges of wrist, elbow and shoulder joints were measured and reported during performed trials. The second aim was to determine whether the movement execution and ranges of move­ments and muscular activity depend on age. Material and methods: Twenty-eight healthy adults, age range 21 to 65 years old, participated in the study. Surface electrodes were placed bilaterally on 7 upper extremity muscles. To obtain information about the beginning and end of the movement task and ranges of upper extremity joints, 13 markers were placed on the elbows and wrists of both upper extremities. The move­ments of the segments were calculated (distal vs proximal) in five simple functional tasks (each task involved only one joint), performed while sitting. Kinematic data were collected by the VICON 460 system, and electromyographic data with the Mo­tion Lab EMG system. Results: Charts of timing of EMG activity of the upper extremity muscles together with ranges of upper extremity joint motion were obtained. Conclusion: The results show that the number of muscles activated and the time (or percentage) of the task during which they are active depend on the type of the task and age. These data can be used as a reference in evaluation of functional deficits of patients.

Glioblastoma multiforme (GBM) represents the most common and aggressive malignant form of brain tumour in adults and is characterized by an extremely poor prognosis with dismal survival rates. Currently, expanding concepts concerning the pathophysiology of GBM are inextricably linked with neuroinflammatory phenomena. On account of this fact, the identification of novel pathomechanisms targeting neuroinflammation seems to be crucial in terms of yielding successful individual therapeutic strategies. In recent years, the pleiotropic growth factor progranulin (PGRN) has attracted significant attention in the neuroscience and oncological community regarding its neuroimmunomodulatory and oncogenic functions. This review of the literature summarizes and updates contemporary knowledge about PGRN, its associated receptors and signalling pathway involvement in GBM pathogenesis, indicating possible cellular and molecular mechanisms with potential diagnostic, prognostic and therapeutic targets in order to yield successful individual therapeutic strategies. After a review of the literature, we found that there are possible PGRN-targeted therapeutic approaches for implementation in GBM treatment algorithms both in preclinical and future clinical studies. Furthermore, PGRN-targeted therapies exerted their highest efficacy in combination with other established chemotherapeutic agents, such as temozolomide. The results of the analysis suggested that the possible implementation of routine determinations of PGRN and its associated receptors in tumour tissue and biofluids could serve as a diagnostic and prognostic biomarker of GBM. Furthermore, promising preclinical applications of PGRN-related findings should be investigated in clinical studies in order to create new diagnostic and therapeutic algorithms for GBM treatment. [ABSTRACT FROM AUTHOR]

Magnetic hopfions are localized magnetic solitons with a nonzero 3D topological charge (Hopf index). Herein, an analytical calculation of the magnetic hopfion gyrovector is presented and it is shown that it does not vanish even in an infinite sample. The calculation method is based on the concept of the emergent magnetic field. The particular case of the simplest nontrivial toroidal hopfion with the Hopf index |QH|=1$\left|\right. Q_{\text{H}} \left|\right. = 1$ in the cylindrical magnetic dot is considered and dependencies of the gyrovector components on the dot sizes are calculated. Nonzero hopfion gyrovector is important in any description of the hopfion dynamics within the collective coordinate Thiele's approach. [ABSTRACT FROM AUTHOR]

Cylindrical ferromagnetic nanowires are of particular interest in nanomaterials science due to various manufacturing methods and a wide range of applications in nanotechnology, with special attention given to those with diameters less than the single domain limit. In the current study, the simulations of magnetic properties of isolated iron nanowires with a diameter of 5 nm and various aspect ratios, as well as two types of arrays of such nanowires (with hexagonal and square arrangement), were performed using atomistic spin model. In the case of a single nanowire, change of coercive field for different applied field directions with aspect ratio was discussed. It was shown that the evolution of the magnetization reversal mechanism from coherent rotation to domain wall propagation appears with increasing length of single nanowire. For the arrays of cylindrical nanostructures, it was revealed that different number of nearest neighbors for each nanostructure in square and hexagonal arrays have an influence on their magnetostatic interactions, which are the most significant for shortest interwire distances. The corresponding spin configurations during the remagnetization process showed the appearance of intermediate magnetization states (when a part of wires is magnetized parallel and part antiparallel to the field direction), connected with Barkhausen effect, which influence the observed hysteresis curves. [ABSTRACT FROM AUTHOR]

PURPOSE: Restrictions related to the COVID-19 pandemic can negatively affect patients who require physiotherapy. This study aimed to analyze the consequences of limited physiotherapy on the functional state of children with neuromuscular diseases (NMD). In addition, the caregivers' well-being and caregiver opinions on physiotherapy were analyzed. METHODS: A questionnaire was shared with parents of children with NMD immediately after the COVID-19 lockdown. The survey included questions regarding the physical and mental condition of children and parents before the pandemic and during lockdown as well as their views on physiotherapy and telephysiotherapy. Statistical analysis was performed using the Wilcoxon Matched-Pairs Signed Ranks test, Spearman's Rank Correlation test, McNemar test, and Chi-square test. RESULTS: Parents of 235 children participated in the study. Results indicated that children devoted more time to physiotherapy before the pandemic than during the lockdown period, which was true for those living in cities and the countryside. The functional state of 50.2% of the children deteriorated during the lockdown, in the opinion of their parents. Significant correlations were found between limited physiotherapy time and the deterioration of children's functional condition, ability to maintain a standing position, and increased anxiety. The majority of parents reported increased levels of fear and anxiety (72.8%), fatigue (67.7%), and pain (53.2%). In-person physiotherapy was rated significantly higher than telephysiotherapy by parents. CONCLUSIONS: Limited access to physiotherapy and shorter therapy times may lead to functional deterioration in children with NMD, but this assumption needs to be objectively confirmed. According to the parents' opinions, telephysiotherapy is less beneficial than direct physiotherapy but may support therapy conducted directly by a physiotherapist. Results based on subjective parental opinions may be helpful in planning future projects. [ABSTRACT FROM AUTHOR]

Inclusion of spin waves into the computing paradigm, where complementary metal‐oxide‐semiconductor devices are still at the fore, is now a challenge for scientists around the world. In this work, a wave phenomenon that has not yet been used in magnonics‐self‐imaging, also known as the Talbot effect, to design and simulate the operation of interference systems that perform logic functions on spin waves in thin ferromagnetic multimode waveguides is utilized. Lookup tables operating in this way are characterized by high programmability and scalability; thanks to which they are promising for their implementation in field‐programmable gate arrays circuits, where multiple logic realizations can be obtained. [ABSTRACT FROM AUTHOR]

Nontrivial magnetization textures, such as skyrmions, have become a driving force in the physics of magnetism. Furthermore, the utilization of magnetization textures is fueling the development of magnon-based technologies that could provide beyond-CMOS solutions. Here, using a self-developed spin wave (SW) excitation scheme, we selectively excite specific modes and investigate the scattering of SWs on nanodot hosting a Néel-type skyrmion and placed above a multimode waveguide. In particular, at low frequencies, we observe significant reflections from the imprint induced by the skyrmion upon the waveguide. As the frequency increases, the transmission increases as well; however, it is accompanied by scattering to other types of modes. Here, we observe a direct contribution of the skyrmion to the scattering process and various types of conversions of the incident SW modes into other modes quantized by width for both reflected and transmitted SWs. The utilization of imprinted magnetization textures in nonplanar systems to control SW flow can open new possibilities for developing SW-based circuits for ultralow-power signal processing. [ABSTRACT FROM AUTHOR]

Self-imaging of waves is an intriguing and spectacular effect. The phenomenon was first observed for light in 1836 by Henry Fox Talbot and to this day is the subject of research in many areas of physics, for various types of waves and in terms of different applications. This article is a Talbot-effect study for spin waves (SWs) in systems composed of a thin, ferromagnetic waveguide with a series of single-mode sources of SWs flowing into it. The proposed systems are studied with the use of micromagnetic simulations, and the SW self-imaging dependencies on many parameters are examined. We formulated conditions required for the formation of self-images and suitable for experimental realization. The results of the research form the basis for the further development of self-imaging-based magnonic devices. [ABSTRACT FROM AUTHOR]

This is the first report of the application of the plane wave method to the solution of the Walker equation for the magnetostatic potential in periodic magnetic composites referred to as magnonic crystals. The discussed method allows to determine the dispersion relation of magnetostatic waves in systems composed of magnetic materials as well as those comprising both magnetic and nonmagnetic materials described by the permeability tensor the elements of which are periodic functions of position. Here the method is applied to the case of one-dimensional magnonic crystals composed of alternating layers of a ferromagnet and a nonmagnetic material. The resulting band structure includes bands of backward magnetostatic waves and a band of surface magnetostatic waves, strongly dependent on the direction of propagation. The obtained results verify the applicability of the method to the considered systems, and suggest it could be used also for calculating spectra of magnetostatic and spin waves in two-dimensional magnonic crystals. Index Terms--Magnetostatic waves, magnonic crystals, superlattice.

The phase is one of the fundamental properties of a wave that allows to control interference effects and can be used to efficiently encode information. We examine numerically a magnonic resonator of the Gires–Tournois interferometer type, which enables the control of the phase of spin waves (SWs) reflected from the edge of the ferromagnetic film. The considered interferometer consists of a Py thin film and a thin, narrow Py stripe placed above its edge, both coupled magnetostatically. We show that the resonances and the phase of the reflected SWs are sensitive for a variation of the geometrical parameters of this bi-layered part of the system. The high sensitivity to film, stripe, and non-magnetic spacer thicknesses offers a prospect for developing magnonic metasurfaces and sensors. [ABSTRACT FROM AUTHOR]

Antidot lattices have proven to be a powerful tool for spin wave band structure manipulation. Utilizing time-resolved scanning transmission x-ray microscopy, we are able to experimentally image edge-localized spin wave modes in an antidot lattice with a lateral confinement down to < 80 nm × 130 nm. At higher frequencies, spin wave dragonfly patterns formed by the demagnetizing structures of the antidot lattice are excited. Evaluating their relative phase with respect to the propagating mode within the antidot channel reveals that the dragonfly modes are not directly excited by the antenna but need the propagating mode as an energy mediator. Furthermore, micromagnetic simulations reveal that additional dispersion branches exist for a tilted external field geometry. These branches correspond to asymmetric spin wave modes that cannot be excited in a non-tilted field geometry due to the symmetry restriction. In addition to the band having a negative slope, these asymmetric modes also cause an unexpected transformation of the band structure, slightly reaching into the otherwise empty bandgap between the low frequency edge modes and the fundamental mode. The presented phase resolved investigation of spin waves is a crucial step for spin wave manipulation in magnonic crystals. [ABSTRACT FROM AUTHOR]

The use of spin waves as a signal carrier requires developing the functional elements allowing for multiplexing and demultiplexing information coded at different wavelengths. For this purpose, we propose a system of thin ferromagnetic layers dynamically coupled by a rectangular ferromagnetic resonator. We show that single and double, clockwise and counterclockwise, circulating modes of the resonator offer a wide possibility of control of propagating waves. Particularly, at frequency related to the double-clockwise circulating spin-wave mode of the resonator, the spin wave excited in one layer is transferred to the second one where it propagates in the backward direction. Interestingly, the wave excited in the second layer propagates in the forward direction only in that layer. This demonstrates add-drop filtering and circulator functionality. Thus, the proposed system can become an important part of future magnonic technology for signal routing. [ABSTRACT FROM AUTHOR]

Background and Purpose: Many stroke trials include maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) outcome measurements. However, data on agreement and reliability of repeated MIP, MEP, and SNIP measurements in acute and subacute stroke patients are scarce. Methods: This study employed a test–retest design. Eighteen patients (seven female) with mean (SD) age 59 (14.5) years were recruited from neurological wards. Median (range) time since first stroke was 50.5 (21–128) days. MIP, MEP, and SNIP were measured repeatedly in three testing sessions (S1–3) conducted within 24 h and following international standards. Intra‐rater agreement between testing sessions was analyzed using the Bland–Altman method. Test–retest reliability was analyzed using intra‐class correlation coefficient (ICC). Association between individual measurement variability, time poststroke, and level of stroke impairment was analyzed using Spearman's rho. Results: Mean difference and 95% limits of agreement for MIP were −0.40 (−23.02, 22.22) cmH2O between S1 and S2, and 2.14 (−12.79, 16.99) cmH2O between S2 and S3; for MEP, −4.56 (−29.01, 19.90) cmH2O between S1 and S2, and 0.29 (−24.28, 24.87) cmH2O between S2 and S3; and for SNIP, −10.56 (−38.48, 17.37) cmH2O between S1 and S2, and −6.06 (−27.32, 15.20) cmH2O between S2 and S3. ICCs for MIP, MEP, and SNIP were ≥0.9 throughout. There were no strong correlations between individual measurement variability and time poststroke or level of stroke impairment. Discussion: MIP, MEP, and SNIP in acute and subacute stroke patients show good test–retest reliability for group averages; however, absolute agreement can vary considerably for some individuals. [ABSTRACT FROM AUTHOR]

The excitation of high-frequency short-wavelength spin waves is a challenge limiting the application of these propagating magnetization disturbances in information processing systems. We propose a method of local excitation of the high-frequency spin waves using the non-linear nature of magnetization dynamics. We demonstrate with numeric simulations that an edge-localized spin wave can be used to excite plane waves propagating obliquely from the film's edge at a doubled frequency and over twice shorter in wavelength. The excitation mechanism is a direct result of the ellipticity of the magnetic moment precession that is related to the edge-mode propagation. As a consequence, the magnetization component tangential to the equilibrium orientation oscillates with doubled temporal and spatial frequencies, which leads to efficient excitation of the plane spin waves. The threshold-less non-linear process of short-wavelength spin-wave excitation proposed in our study is promising for integration with an inductive or point-like spin-torque source of edge spin waves. [ABSTRACT FROM AUTHOR]