Body Interaction Research Articles

Breathing-driven prefrontal oscillations regulate maintenance of conditioned-fear evoked freezing independently of initiation

Brain–body interactions are thought to be essential in emotions but their physiological basis remains poorly understood. In mice, regular 4 Hz breathing appears during freezing after cue-fear conditioning. Here we show that the olfactory bulb (OB) transmits this rhythm to the dorsomedial prefrontal cortex (dmPFC) where it organizes neural activity. Reduction of the respiratory-related 4 Hz oscillation, via bulbectomy or optogenetic perturbation of the OB, reduces freezing. Behavioural modelling shows that this is due to a specific reduction in freezing maintenance without impacting its initiation, thus dissociating these two phenomena. dmPFC LFP and firing patterns support the region’s specific function in freezing maintenance. In particular, population analysis reveals that network activity tracks 4 Hz power dynamics during freezing and reaches a stable state at 4 Hz peak that lasts until freezing termination. These results provide a potential mechanism and a functional role for bodily feedback in emotions and therefore shed light on the historical James–Cannon debate.

Enhancing performance and reducing wearing variability for wearable technology system–body interfaces using shape memory materials

Advancements in e-textiles, sensors, and actuators have propelled wearable technologies toward wide-spread market use, however the physical interface between these technologies and the human body has remained a functional challenge. Prior research has found that system–body interface challenges produce wearing variability, or variation in system placement, orientation, and tightness in relation to a body both between use trials and between users, resulting in large variation and deterioration in system performance. We break down the mechanics of common system–body interface challenges through a summary of design principles critical to any system interfacing with the human body. Additionally, we present an active interface based on shape memory materials that dimensionally adapts to its user’s dimensions. An experimental investigation of these active system interfaces considers the impact of design variables often overlooked in the design process. Recommendations are provided to optimize interfaces for the requirements for a given wearable technology. Additionally, we illuminate methods to reduce wearing variability for a range of users to produce consistent system–body interaction across a user population. Through these active interfaces, we advance a broad range of wearable technologies, including wearable sensing, motion tracking, haptics, and wearable robotic devices.

Measure-Valued Solutions and Weak–Strong Uniqueness for the Incompressible Inviscid Fluid–Rigid Body Interaction

We consider a coupled system of partial and ordinary differential equations describing the interaction between an incompressible inviscid fluid and a rigid body moving freely inside the fluid. We prove the existence of measure-valued solutions which is generated by the vanishing viscosity limit of incompressible fluid–rigid body interaction system under some physically constitutive relations. Moreover, we show that the measure-valued solution coincides with strong solution on the interval of its existence. This relies on the weak–strong uniqueness analysis. This is the first result of an existence of measure-valued solution and weak–strong uniqueness in measure-valued sense in the case of inviscid fluid–structure interaction.

Control of TRPML1 Channel Activity and Lysosome Trafficking by Acid Ceramidase in Mouse Coronary Arterial Endothelial Cells

Previous studies have demonstrated that lysosomal acid ceramidase (AC) regulates lysosome-multivesicular body (MVB) interaction and exosome release in mouse coronary arterial endothelial cells (CAECs). However, it remains unknown how exosome secretion is controlled by AC. In this study, we tested a hypothesis that enhancement of lysosome trafficking by AC activity increases lysosome-MVB interaction determining MVB fate to promote exosome release, which may be attributed to its action on lysosomal TRPML1 channel-mediated Ca2+ release in CAECs. By GCaMP3 Ca2+ imaging, we found that ML-SA1 as a TRPML1 channel agonist remarkably increased lysosomal Ca2+ release through TRPML1 channel in WT/WT CAECs. In Asah1fl/fl/ECcre CAECs, however, ML-SA1 failed to influence TRPML1 channel-mediated Ca2+ release. As an AC product, sphingosine remarkably increased lysosomal Ca2+ release through TRPML1 channel in both WT/WT and Asah1fl/fl/ECcre CAECs. With whole-lysosome patch clamp recording, we detected ML-SA1-induced Ca2+ currents in a dose-dependent manner through the membrane of lysosomes isolated from WT/WT CAECs, while intact lysosomes isolated from Asah1fl/fl/ECcre CAECs had evidently blunted opening of TRPML1 channels in response to ML-SA1. Different effects of AC associated sphingolipids on TRPML1 channel activity were also examined in lysosomes isolated from WT/WT CAECs. It was found that sphingomyelin inhibited, but sphingosine enhanced lysosomal TRPML1 channel activity. Ceramide did not alter this lysosomal channel activity. In lysosomes isolated from Asah1fl/fl/ECcre CAECs, only sphingosine increased ML-SA1-induced TRPML1 channel-mediated Ca2+ release. Using confocal microscopy for measurement of lysosomes movement, we demonstrated that lysosomal TRPML1 channel activation by ML-SA1 in CAECs markedly enhanced lysosome trafficking toward nucleus, which was blocked by genetic deletion of AC. These results suggest that AC-mediated sphingolipid metabolism controls lysosomal TRPML1 channel-mediated Ca2+ release and lysosome trafficking in CAECs, which may contribute to the regulation of lysosome-MVB interaction and exosome release by AC (supported by NIH grant DK120491).

Interactions of waves with a body floating in an open water channel confined by two semi-infinite ice sheets

Abstract

Numerical Analysis of the Dynamic Interaction between Two Closely Spaced Vertical-Axis Wind Turbines

To investigate the optimum layouts of small vertical-axis wind turbines, a two-dimensional analysis of dynamic fluid body interaction is performed via computational fluid dynamics for a rotor pair in various configurations. The rotational speed of each turbine rotor (diameter: D = 50 mm) varies based on the equation of motion. First, the dependence of rotor performance on the gap distance (gap) between two rotors is investigated. For parallel layouts, counter-down (CD) layouts with blades moving downwind in the gap region yield a higher mean power than counter-up (CU) layouts with blades moving upwind in the gap region. CD layouts with gap/D = 0.5–1.0 yield a maximum average power that is 23% higher than that of an isolated single rotor. Assuming isotropic bidirectional wind speed, co-rotating (CO) layouts with the same rotational direction are superior to the combination of CD and CU layouts regardless of the gap distance. For tandem layouts, the inverse-rotation (IR) configuration shows an earlier wake recovery than the CO configuration. For 16-wind-direction layouts, both the IR and CO configurations indicate similar power distribution at gap/D = 2.0. For the first time, this study demonstrates the phase synchronization of two rotors via numerical simulation.

Body mass index and bullying victimization as antecedents for depressive symptoms in a Swedish youth cohort

AimThe bidirectional association between obesity and depression seen in adults is not clearly established in adolescents. The aim of this study was to investigate the longitudinal association between body mass index (BMI), depressive symptoms and interactions between bullying victimization and BMI, taking gender differences into account.Subjects and methodsIn a Swedish county, self-reported bullying victimization, BMI and depressive symptoms from 1729 adolescents ( overline{y} = 14.4, 56% females) were collected in 2012 (wave 1), in 2015 (wave 2) ( overline{y}=17.3 ) and in 2018 (wave 3) ( overline{y} = 19.9). Longitudinal associations were assessed using binary logistic regression models controlling for confounding factors. Interaction effects between BMI and victimization on depressive symptoms were also assessed.ResultsWave 1 obese males had approximately six times increased odds ratio compared to normal weight, for wave 2 depressive symptoms. W1 overweight was associated with an odds ratio of 1.5 in all participants for wave 3 depressive symptoms. Victimization was consistently associated with higher odds ratio for future depressive symptoms. We found interaction effects between bullying victimization and BMI for future depressive symptoms with different patterns depending on sex.ConclusionGiven the present findings, bullying needs to be prevented, and, if it occurs, it needs to be stopped at an early stage to prevent future depressive symptoms.

Modulating Microtubules: A Molecular Perspective on the Effects of Tail Modifications

Microtubules (MTs), an essential component of the eukaryotic cytoskeleton, are a lattice of polymerized tubulin dimers and are crucial for various cellular processes. The genetic and chemical diversity of tubulin and their disordered tails gives rise to a “tubulin code”. The functional role of tubulin post-translational modifications (PTMs), which contribute to the chemical diversity of the tubulin code, is gradually being unraveled. However, variation in the length and spatial organization of tubulin poly-modifications leads to an enormous combinatorial PTM space, which is difficult to study experimentally. Hence, the impact of the combinatorial tubulin PTM space on the biophysical properties of tubulin tails and their interactions with other proteins remains elusive.Here, we combine all-atom and coarse-grained molecular dynamics simulations to elucidate the biophysical implications of the large combinatorial tubulin PTM space in the context of an MT lattice. We find that tail–body interactions are more dominant in the tubulin dimer than in an MT lattice, and are more significant for the tails of α compared with β tubulin. In addition, polyglutamylation, but not polyglycylation, expands the dimensions of the tubulin tails. Polyglutamylation also leads to a decrease in the diffusion rate of MT-associated protein EB1 on MTs, while polyglycylation often increases diffusion rate. These observations are generally not sensitive to the organization of the polymodifications. The effect of PTMs on MT charge density and tail dynamics are also discussed. Overall, this study presents a molecular quantification of the biophysical properties of tubulin tails and their polymodifications, and provides predictions on the functional importance of tubulin PTMs.

Моделирование траектории судна на волнах на базе STAR-CCM+

The reliable ship motion trajectory signal provides a basis for six-degree-of-freedom test bench to simulate ship motion in waves. The characteristics of ship motion in waves were analyzed. Aiming at the problem of complex hull shape and large displacement at sea, the dynamic overlapping grid technique was used. Based on STAR-CCM+, the free surface was solved by CFD (Computational Fluid Dynamics) numerical simulation method. The numerical model of ship motion in waves was established, and the DFBI (Dynamic Fluid Body Interaction) method was used to simulate the ship motion in the waves. The ship’s motion trajectory was obtained in the regular and irregular heading waves, which provides important support for the six-degree-of-freedom test bench wave simulation system.

REFLEXÕES SOBRE EDUCAÇÃO INFANTIL EM TEMPOS DE PANDEMIA DO COVID-19

RESUMO: O presente artigo tem o propósito de refletir sobre a Educação Infantil em tempos de Pandemia do COVID-19 e a formação continuada de seus professores. Destaca-se que a criança nessa faixa etária, tem passado pelo desafio de ficar em casa com a família e devido ao distanciamento social, enfrenta a inibição de seus movimentos corporais e interações. Cada criança está inserida em um contexto familiar diferente. Então, como a escola e a família vão criar novos espaços para o aprender prazeroso de cada criança? A formação continuada do professor é um ponto interessante de ser pensado, já que o ensino remoto chegou também para a Educação Infantil. Alguns autores foram aportes teóricos, como: Imbernón (2010); Perrenoud (2000); Moraes (1997); Camões; Toledo; Roncarati (2013); outros. Nesse sentido, esse artigo tem o objetivo de ressaltar a importância da formação continuada do professor da Educação Infantil para promover a qualidade do ensino e de vida das crianças.

Data-driven stability analysis and near-wake jet control for the vortex-induced vibration of a sphere

We present a stability analysis for the vortex-induced vibration (VIV) of a sphere and a suppression control technique using a base bleed actuation. The reduced-order model (ROM) for the system is developed via the eigensystem realization algorithm (ERA), which provides a low-order representation of the unsteady flow dynamics in the neighborhood of the equilibrium steady state. A systematic ROM-based stability analysis is performed to understand the frequency lock-in mechanism and self-sustained VIV phenomenon by examining the eigenvalue trajectories for a range of reduced oscillation frequencies (Fs) at fixed Reynolds number (Re) and mass ratio (m*). Consistent with the full-order simulations, the ERA-based ROM predicts the frequency lock-in branches arising due to resonance and combined mode instabilities. The dependence of these lock-in branches is explored as a function of mass ratio. The base bleeding mechanism in the near-wake region of a sphere and its influence over the flow dynamics, the wake characteristics, and the VIV response are investigated for the freely vibrating sphere system at Re = 300. A base bleed coefficient (Cq) is defined as a ratio of near-wake jet flow rate to the freestream inflow rate to perform a parametric analysis on the hydrodynamic coefficients and the flow features. It is found that a near-wake jet with Cq=1% inhibits the synchronization of the shedding process and completely suppresses the large-amplitude oscillations for all VIV branches studied. In addition, we demonstrate the reduction of the mean drag coefficient by more than 14% in comparison to the sphere alone system. The stability analysis of the near-wake jet is performed for the sphere VIV. The resulting ROM provides an effective approach for the parameter space exploration and is able to characterize the effectiveness of the designed controller on the VIV suppression. Results from the ROM analysis are consistent with those obtained from our full-order nonlinear fluid–structure interaction simulations. The present study illustrates that VIV can be suppressed by altering the structure mode via shifting the unstable wake modes to the stable region. This finding is realized through the simulations of an active control device, wherein the presence of near-wake jet flow breaks the self-sustenance of the wake–body interaction cycle. Overall, the proposed base-bleed control is found to be effective in suppressing the vortex shedding and the VIV for a range of reduced velocities and mass ratios.

Optimization of Energy Extraction Using Definite Geometry Prisms in Airflow

Abstract An approximate method for analysis and synthesis of moving rigid bodies (prisms) in the airflow without using numerical methods of space-time programming techniques is described by applying a fluid (air)–rigid solid body interaction concept for engineering applications through a straightforward mathematical model. The interaction of rigid body (prism) and air is encountered in different cases: moving body (prism) in the air; stationary bodies (prism) in the airflow; moving body (prism) in the airflow. The complicated task of rigid body (prism) and air interaction is simplified by using superposition principles, i.e., by taking into account the upstream and downstream rigid body (prism) and air interaction phenomenon, which has been found to be different under varying speeds. Numerical results obtained for various forms of prisms are shown for constant air–speed, where the steady state Reynolds-averaged Navier–Stokes (RANS) equation is solved by using k-ε realizable turbulence model. A detailed explanation to support the proposed approximate method is given by using numerical results obtained in ANSYS computations. All equations are formed based on laws of classical mechanics; the interaction of viscous forces is neglected in forming the mathematical model. Numerical results for different model prisms are compared and the theoretical results discussed in detail. The mathematical model in the present paper is applicable only to bodies that undergo a rectilinear translation motion. In the final part of the present paper, the proposed method is used in the synthesis and optimization task of energy extraction by considering the motion of a variable parameter prism in the airflow.

Application of the Fourier–Kochin theory for the diffraction and radiation of free-surface waves about stationary floating bodies

The classical problem of time-harmonic diffraction and radiation of free-surface flows due to wave–body interaction is revisited based on the Fourier–Kochin theory for zero forward speed. The key idea of the Fourier–Kochin theory is reversing the order of the two fundamental tasks of the Green function based direct solutions of free-surface flows, i.e., evaluation of the Green function and its gradient, and their subsequent integration over the boundary surface. By implementing a higher-order numerical approximation along with the use of extended boundary integral equation method to suppress the irregular frequencies, three different bodies – a hemisphere, a vertical cylinder, and a frigate model – are studied. The Fourier–Kochin framework accurately captures the radiated and diffracted flow about oscillating bodies, in general, but slight irregularities are also observed at high frequencies for complicated body forms. Since the floating body is stationary here, the problem has a standard, unambiguous solution and the indirect approach introduced by the Fourier–Kochin theory may not seem worthwhile to adopt; however, its perspective becomes rewarding when the forward speed effects are considered. As a premise of this idea, the main goals here are to assess the practical application of the theory, to identify the challenges, and to investigate how to surmount them.

A potential flow method combining immersed boundaries and overlapping grids: Formulation, validation and verification

A fully nonlinear two-dimensional numerical method based on potential-flow theory for water waves and their interaction with surface-piercing rigid bodies is presented. The harmonic polynomial cell (HPC) method is used to solve the Laplace equation for the velocity potential and its time derivative. The HPC method, which is a high-order method using analytical expressions (harmonic polynomials) to represent the solution inside overlapping cells, has previously been shown accurate and efficient. Supplementary research has shown that, in order to maximally benefit from the method’s accuracy, it is a requirement that square or close-to-square cells are used. Here, we use an immersed boundary method to model non-stationary boundaries such as the free surface or the surface of a rigid body, and overlapping, body-fixed grids that are locally Cartesian to refine the solution near moving bodies. Combining these two modelling concepts with the HPC method represents the main novel contribution in the present work. With this combined method, denoted as an immersed-boundary overlapping grid method (IBOGM), the challenge of generating boundary-fitted grids for complex boundaries is avoided. Moreover, square cells can be used throughout the domain and the solution can be refined locally without increasing the number of unknowns unnecessarily. The method is systematically validated and verified against analytical, experimental and numerical reference results. The cases studied include propagation of steep waves, forced heave motions of a semi-submerged circular cylinder and a fixed and freely floating ship section in beam-sea waves. For the freely floating ship section, the present method is compared in detail with results from a dedicated study performed with a fully nonlinear boundary element method for cases with roll motions up to 30°. The present results are generally in good agreement with reference results, even for the most challenging wave–body interaction cases considered. Based on this, we later intend to use the method to examine in depth the importance of nonlinear effects in the interaction between waves and rigid bodies.

Lower visual field preference for the visuomotor control of limb movements in the human dorsomedial parietal cortex

Visual cues coming from the lower visual field (VF) play an important role in the visual guidance of upper and lower limb movements. A recently described region situated in the dorsomedial parietal cortex, area hPEc (Pitzalis et al. in NeuroImage 202:116092, 2019), might have a role in integrating visually derived information with somatomotor signals to guide limb interaction with the environment. In macaque, it has been demonstrated that PEc receives visual information mostly from the lower visual field but, to date, there has been no systematic investigation of VF preference in the newly defined human homologue of macaque area PEc (hPEc). Here we examined the VF preferences of hPEc while participants performed a visuomotor task implying spatially directed delayed eye-, hand- and foot-movements towards different spatial locations within the VF. By analyzing data as a function of the different target locations towards which upcoming movements were planned (and then executed), we observed the presence of asymmetry in the vertical dimension of VF in area hPEc, being this area more strongly activated by limb movements directed towards visual targets located in the lower compared to the upper VF. This result confirms the view, first advanced in macaque monkey, that PEc is involved in processing visual information to guide body interaction with the external environment, including locomotion. We also observed a contralateral dominance for the lower VF preference in the foot selective somatomotor cortex anterior to hPEc. This result might reflect the role of this cortex (which includes areas PE and S-I) in providing highly topographically organized signals, likely useful to achieve an appropriate foot posture during locomotion.

Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe_{2}/WSe_{2} Heterobilayers.

Charge separated interlayer excitons in transition metal dichalcogenide heterobilayers are being explored for moiré exciton lattices and exciton condensates. The presence of permanent dipole moments and the poorly screened Coulomb interaction make many-body interactions particularly strong for interlayer excitons. Here we reveal two distinct phase transitions for interlayer excitons in the MoSe_{2}/WSe_{2} heterobilayer using time and spatially resolved photoluminescence imaging: from trapped excitons in the moiré potential to the modestly mobile exciton gas as exciton density increases to n_{ex}∼10^{11} cm^{-2} and from the exciton gas to the highly mobile charge separated electron-hole plasma for n_{ex}>10^{12} cm^{-2}. The latter is the Mott transition and is confirmed in photoconductivity measurements. These findings set fundamental limits for achieving quantum states of interlayer excitons.

Detailed investigation of dynamic of Bose–Einstein condensation with two, three body and higher-order interactions

In this study, we investigate the effects of three body and higher-order interactions (HOIs) with two-body interaction on ground state properties of Bose–Einstein condensation (BEC) for combined optical and harmonic potentials in detail by solving new modified Gross–Pitaevskii equation (GPE). In fact, the basis of the study is combinations of attractive and repulsive two-body interaction with other attractive and repulsive interaction types. The obtained results show that taking into account higher order and three-body interactions collectively support to stabilize the BEC system regardless of repulsive or attractive two-body interaction. When repulsive (attractive) binary interaction exists in the system, having at least one attractive (repulsive) interaction type makes the system stable. Also, the stability of the BEC system is discussed by the calculating energy. The energy of the system is determined by semi-analytical approach. Finally, the chemical potential of system is calculated according to different possible combined interaction types. It is observed that generally, the sign of the chemical potential is determined by sign of the strongest interaction in the system, especially three-body interaction. Detailed results are given in this paper.

Correlation between kinetic fragility and Poisson's ratio from analysis of data for soft colloids

We consider the link between fragility and elasticity that follows from the analysis of the data for a set of soft colloid materials consisting of deformable spheres reported by [Mattsson et al., Nature, 2009, 462, 83]. The present work makes a quantitative analysis through an explicit definition for fragility index m in terms of density dependence, extending the corresponding formula of m for molecular systems in terms of temperature dependence. In addition, we fit the data for the high-frequency shear modulus for the respective soft-colloid to a corresponding theoretical expression for the same modulus. This expression for the elastic constant is in terms of the corresponding pair correlation function for the liquid treated as of uniform density. The pair correlation function is adjusted through a proper choice of the parameters for the two body interaction potential for the respective soft-colloid material. The nature of correlation between the fragility and Poisson ratio observed for the soft colloids is qualitatively different, as compared to the same for molecular glasses. The observed link between fragility of a metastable liquid and its elastic coefficients is a manifestation of the effects of structure of the fluid on its dynamics. The present work thus analyses the data on soft colloids and by introducing definitions from statistical mechanics obtains a correlation between kinetic fragility and Poissons's ratio for the soft material.

Gradient descent dynamics in the mixed p-spin spherical model: finite-size simulations and comparison with mean-field integration

We perform numerical simulations of a long-range spherical spin glass with two and three body interaction terms. We study the gradient descent dynamics and the inherent structures found after a quench from initial conditions well thermalized at temperature T in. In very large systems, the dynamics perfectly agrees with the integration of the mean-field dynamical equations. In particular, we confirm the existence of an onset initial temperature, within the liquid phase, below which the energy of the inherent structures undoubtedly depends on T in. This behavior is in contrast with that of pure models, where there is a ‘threshold energy’ that attracts all the initial configurations in the liquid. Our results strengthen the analogy between mean-field spin glass models and supercooled liquids.

Studying Inelastic Electron Scattering of Magnetic Form Factors M1 for 48Ca Nucleus Using Skyrme Interaction

The M1 inelastic scattering form factors from 48Ca nucleus have been investigated through nuclear shell theory. The nuclear effective two body interaction fpbm of Richter has been utilized to generate the two body wave vectors with Harmonic oscillator wave function as a single particle wave function in Fp shell model space. Core polarization effect has been used to include the discarded space (core+ higher configuration) via model space with realistic interaction of Skyrme Sly5 to couple the model space active particles with the pair (particle-hole) excited in energy of 2ћω. Calculated results has been compared to available experimental data.