Maximum Relaxation Time Research Articles

Electron-ion relaxation times in 1–100 eV warm dense aluminum and gold

We calculated the electron-ion energy relaxation times in warm dense aluminum and gold. Our calculations span a wide temperature range from a thousand to a million kelvins for both dense aluminum and gold. To determine the temporal evolution of electron and ion temperatures, we employed the two-temperature model with the SESAME equation-of-state tables, and well-known electron-ion coupling factors. Our calculations indicate that the relaxation times for warm dense aluminum were within 5 ps, whereas they were within 20 ps for warm dense gold. The maximum relaxation times were observed at initial electron temperatures of approximately 30,000 K for both aluminum and gold. Our calculated relaxation times using the SESAME database agree very well with the existing theories both in the cold-solid and hot-plasma limits. Furthermore, we found that the melting times calculated using the Lindemann criterion were in good agreement with the melting times for gold from measurements in recent literature.

Spinel ferrites having conductive grains, resistive interfacial boundaries and relaxation mechanism for possible supercapacitor applications

Linear increase in crystallite size (16–24 nm) of MnxZn1−xFe2O4 nanostructures and mixed behavior of lattice constant (8.429–8.462 Å) is reported. The system exhibits considerable promise for microwave applications due to its elevated dielectric constants and minimal dispersion losses from 20 Hz to 20 MHz. With x = 0.75, sample is good for energy storage devices like supercapacitors due to large specific surface area (53 m2/g) and dielectric constant. These samples exhibit maximum relaxation times ranging from 1.97 × 10−7 s to 2.43 × 10−4 s, with corresponding relaxation energy values spanning from 159.22 meV to 341 meV for x = 0 and x = 1 samples. The Cole-Cole plots reveal that grains exhibit conductive behavior at lower frequencies, while grain boundaries contribute significantly to the resistive behavior. Additionally, we have introduced Bode diagrams and equivalent electronic circuit models for the first time, offering valuable insights into the electrical behavior of the nanomaterial samples.

Multiscale simulations of viscoelastic fluids in complex geometries using a finitely extensible nonlinear elastic transient network model

This paper presents a novel implementation of a numerical scheme for predicting complex flows of viscoelastic fluids using a finitely extensible nonlinear elastic (FENE) transient network model. This model extends the FENE model by incorporating chain interactions and accounting for the way in which the maximum chain length, drag, and relaxation time are influenced by entanglement and disentanglement processes. Three different initial networks are considered (disentanglement, entanglement, and aleatory), and the influence of variables such as the kinetic rate constants, elasticity, and chain length on the microstate concentration, stresses, and drag force is investigated. It is shown that although the concentrations of the microstates are independent of the Weissenberg number and the maximum extension length, the stresses and hence the drag are influenced by them.

Optimizing the accuracy of viscoelastic characterization with AFM force-distance experiments in the time and frequency domains.

Atomic Force Microscopy (AFM) force-distance (FD) experiments have emerged as an attractive alternative to traditional micro-rheology measurement techniques owing to their versatility of use in materials of a wide range of mechanical properties. Here, we show that the range of time dependent behaviour which can reliably be resolved from the typical method of FD inversion (fitting constitutive FD relations to FD data) is inherently restricted by the experimental parameters: sampling frequency, experiment length, and strain rate. Specifically, we demonstrate that violating these restrictions can result in errors in the values of the parameters of the complex modulus. In the case of complex materials, such as cells, whose behaviour is not specifically understood a priori, the physical sensibility of these parameters cannot be assessed and may lead to falsely attributing a physical phenomenon to an artifact of the violation of these restrictions. We use arguments from information theory to understand the nature of these inconsistencies as well as devise limits on the range of mechanical parameters which can be reliably obtained from FD experiments. The results further demonstrate that the nature of these restrictions depends on the domain (time or frequency) used in the inversion process, with the time domain being far more restrictive than the frequency domain. Finally, we demonstrate how to use these restrictions to better design FD experiments to target specific timescales of a material's behaviour through our analysis of a polydimethylsiloxane (PDMS) polymer sample.

Glass formation and dynamics of model polymer films with one versus two active interfaces.

Polymers and other glass-forming liquids can exhibit profound alterations in dynamics in the nanoscale vicinity of interfaces, over a range appreciably exceeding that of typical interfacial thermodynamic gradients. The understanding of these dynamical gradients is particularly complicated in systems with internal or external nanoscale dimensions, where a gradient nucleated at one interface can impinge on a second, potentially distinct, interface. To better understand the interactions that govern system dynamics and glass formation in these cases, here we simulate the baseline case of a glass-forming polymer film, over a wide range of thickness, supported on a dynamically neutral substrate that has little effect on nearby dynamics. We compare these results to our prior simulations of freestanding films. Results indicate that dynamical gradients in our simulated systems, as measured based upon translational relaxation, are simply truncated when they impinge on a secondary surface that is locally dynamically neutral. Altered film behavior can be described almost entirely by gradient effects down to the thinnest films probed, with no evidence for finite-size effects sometimes posited to play a role in these systems. Finally, our simulations predict that linear gradient overlap effects in the presence of symmetric dynamically active interfaces yield a non-monotonic variation of the whole free standing film stretching exponent (relaxation time distribution breadth). The maximum relaxation time distribution breadth in simulation is found at a film thickness of 4-5 times the interfacial gradient range. Observation of this maximum in experiment would provide an important validation that the gradient behavior observed in simulation persists to experimental timescales. If validated, observation of this maximum would potentially also enable determination of the dynamic gradient range from experimental mean-film measurements of film dynamics.

PROJEÇÃO DA FADIGA E AS ALTERAÇÕES NEUROMUSCULARES PROVOCADAS EM DISTINTAS ATIVIDADES FÍSICAS

ABSTRACT Introduction: Athletes’ muscles can be weakened by fatigue caused by excessive activity. This limitation compromises their functional capacity and professional performance. The competition's performance correlates positively with muscular quality of function. The changes analysis caused by different athletic activities in muscle contraction by noninvasive tensiomyography reflects the functional state of the muscles. Still, no experiments are adapted to verify the fatigue risk level. Objective: Verify the possible relationship between exercise and neuromuscular fatigue using noninvasive tensiomyography. Methods: 90 athletes were randomly selected in weightlifting, badminton, and athletics sports. Maximum radial displacement, contraction, delay, duration, and relaxation time indices were collected. Muscle fatigue detection was based on the empirical mode decomposition modeling method with the Rogers sensitivity fluctuation rate. All values were collected in the rectus femoris muscle before and after the exercises. They were statistically treated and compared (P<0.05). Results: All athletes showed a decline in maximum radial displacement values after exercise. It reveals that their muscles are in a considerable state of tension, especially in the track and field group (from 8.57±3.42mm to 5.43±2.14mm). However, the slightest change in delay time was observed in the weightlifting group (16.21±4.15ms initial versus 18.34±3.27ms final). Conclusion: Through tensiomyography technology, it is possible to obtain a relationship between exercise and neuromuscular fatigue, analyzing the physical activity effects in a noninvasive way. Evidence Level II; Therapeutic Studies - Investigating the result.

Quartic graphs with minimum spectral gap

AbstractAldous and Fill conjectured that the maximum relaxation time for the random walk on a connected regular graph with vertices is . This conjecture can be rephrased in terms of the spectral gap as follows: the spectral gap (algebraic connectivity) of a connected ‐regular graph on vertices is at least , and the bound is attained for at least one value of . We determine the structure of connected quartic graphs on vertices with a minimum spectral gap which enables us to show that the minimum spectral gap of connected quartic graphs on vertices is . From this result, the Aldous–Fill conjecture follows for .

Analysis of Film Blowing with Flow-enhanced Crystallization

Abstract An analysis of the steady-state film blowing process based on a two-phase constitutive model that accounts for flow-enhanced crystallization is presented. The amorphous melt phase is represented by a multi-mode Giesekus constitutive equation with a transformation-dependent relaxation time and the semi-crystalline phase is represented by a rigid rod model. The relaxation times in the two constitutive equations are linked by an Avrami, temperature-dependent rate expression which contains a term in the Helmholtz free energy to account for flow-enhancement. Comparisons are made to experimental data for film blowing of linear low density (LLDPE) and low density (LDPE) polyethylenes. Excellent fits for the bubble radius, temperature, and crystallinity are shown. It is also shown that the ratio of amorphous stress to total stress at the “lock-in” point provides an excellent correlating variable for the elongation to break and yield strength properties of the as-blown film. Inclusion of multiple relaxation times in the Giesekus model offers insights on the controlling role of the maximum relaxation time in the stress profiles and locking-in behavior due to crystallization.

Effects of the surface wettability of nanoparticles on the impact dynamics of droplets

Herein, we report an experimental investigation on droplet impact dynamics with a particular interest in the effects of hydrophilicity and hydrophobicity of particles on the impact dynamics. Remarkable contact line pinning and receding breakup were observed when hydrophobic particles were present in the droplets, while hydrophilic particles showed little effect on the dynamics. Furthermore, the maximum retraction height and vertical oscillatory relaxation time for the droplet were restrained by hydrophobic particles. Scanning electron microscopy and rheological analyses revealed that these phenomena may be related to the adsorption and deposition of hydrophobic particles near the three-phase contact line, which leads to an increase in local viscosity and friction near the edge of the drop. In addition, the contact line pinning is positively associated with the Weber number and particle concentration. Our work provides a novel approach for droplet impact dynamics control, particularly for suppressing the oscillation and contraction of droplets.

Characterization of Open-Cell Sponges via Magnetic Resonance and X-ray Tomography.

The applications of polymeric sponges are varied, ranging from cleaning and filtration to medical applications. The specific properties of polymeric foams, such as pore size and connectivity, are dependent on their constituent materials and production methods. Nuclear magnetic resonance imaging (MRI) and X-ray micro-computed tomography (µCT) offer complementary information about the structure and properties of porous media. In this study, we employed MRI, in combination with µCT, to characterize the structure of polymeric open-cell foam, and to determine how it changes upon compression, µCT was used to identify the morphology of the pores within sponge plugs, extracted from polyurethane open-cell sponges. MRI T2 relaxation maps and bulk T2 relaxation times measurements were performed for 7° dH water contained within the same polyurethane foams used for µCT. Magnetic resonance and µCT measurements were conducted on both uncompressed and 60% compressed sponge plugs. Compression was achieved using a graduated sample holder with plunger. A relationship between the average T2 relaxation time and maximum opening was observed, where smaller maximum openings were found to have a shorter T2 relaxation times. It was also found that upon compression, the average maximum opening of pores decreased. Average pore size ranges of 375–632 ± 1 µm, for uncompressed plugs, and 301–473 ± 1 µm, for compressed plugs, were observed. By determining maximum opening values and T2 relaxation times, it was observed that the pore structure varies between sponges within the same production batch, as well as even with a single sponge.

Assessment of human bioengineered cardiac tissue function in hypoxic and re-oxygenized environments to understand functional recovery in heart failure.

IntroductionMyocardial recovery is one of the targets for heart failure treatment. A non-negligible number of heart failure with reduced ejection fraction (EF) patients experience myocardial recovery through treatment. Although myocardial hypoxia has been reported to contribute to the progression of heart failure even in non-ischemic cardiomyopathy, the relationship between contractile recovery and re-oxygenation and its underlying mechanisms remain unclear. The present study investigated the effects of hypoxia/re-oxygenation on bioengineered cardiac cell sheets-tissue function and the underlying mechanisms.MethodsBioengineered cardiac cell sheets-tissue was fabricated with human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) using temperature-responsive culture dishes. Cardiac tissue functions in the following conditions were evaluated with a contractile force measurement system: continuous normoxia (20% O2) for 12 days; hypoxia (1% O2) for 4 days followed by normoxia (20% O2) for 8 days; or continuous hypoxia (1% O2) for 8 days. Cell number, sarcomere structure, ATP levels, mRNA expressions and Ca2+ transients of hiPSC-CM in those conditions were also assessed.ResultsHypoxia (4 days) elicited progressive decreases in contractile force, maximum contraction velocity, maximum relaxation velocity, Ca2+ transient amplitude and ATP level, but sarcomere structure and cell number were not affected. Re-oxygenation (8 days) after hypoxia (4 days) was associated with progressive increases in contractile force, maximum contraction velocity and relaxation time to the similar extent levels of continuous normoxia group, while maximum relaxation velocity was still significantly low even after re-oxygenation. Ca2+ transient magnitude, cell number, sarcomere structure and ATP level after re-oxygenation were similar to those in the continuous normoxia group. Hypoxia/re-oxygenation up-regulated mRNA expression of PLN.ConclusionsHypoxia and re-oxygenation condition directly affected human bioengineered cardiac tissue function. Further understanding the molecular mechanisms of functional recovery of cardiac tissue after re-oxygenation might provide us the new insight on heart failure with recovered ejection fraction and preserved ejection fraction.

Regular graphs with minimum spectral gap

Aldous and Fill conjectured that the maximum relaxation time for the random walk on a connected regular graph with n vertices is (1+o(1))3n22π2. This conjecture can be rephrased in terms of the spectral gap as follows: the spectral gap (algebraic connectivity) of a connected k-regular graph on n vertices is at least (1+o(1))2kπ23n2, and the bound is attained for at least one value of k. Based upon previous work of Brand, Guiduli, and Imrich, we prove this conjecture for cubic graphs. We also investigate the structure of quartic (i.e. 4-regular) graphs with the minimum spectral gap among all connected quartic graphs. We show that they must have a path-like structure built from specific blocks.

Spin Readout of a CMOS Quantum Dot by Gate Reflectometry and Spin-Dependent Tunneling

Silicon spin qubits are promising candidates for realizing large-scale quantum processors, benefitting from a magnetically quiet host material and the prospects of leveraging the mature silicon device fabrication industry. We report the measurement of an electron spin in a singly occupied gate-defined quantum dot, fabricated using CMOS-compatible processes at the 300-mm wafer scale. For readout, we employ spin-dependent tunneling combined with a low-footprint single-lead quantum-dot charge sensor, measured using rf gate reflectometry. We demonstrate spin readout in two devices using this technique, obtaining valley splittings in the range 0.5–0.7 meV using excited-state spectroscopy, and measure a maximum electron-spin relaxation time (T1) of 9±3 s at 1 T. These long lifetimes indicate the silicon-nanowire geometry and fabrication processes employed here show a great deal of promise for qubit devices, while the spin-readout method demonstrated here is well suited to a variety of scalable architectures.4 MoreReceived 16 May 2020Revised 12 October 2020Accepted 24 February 2021DOI:https://doi.org/10.1103/PRXQuantum.2.010353Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasQuantum computationPhysical SystemsQuantum dotsCondensed Matter, Materials & Applied Physics

Miscibility of Poly(Methyl Methacrylate) and Poly(Vinylidene Fluoride) Examined by Thermally Stimulated Depolarization Current and Dielectric Relaxation Spectroscopy

Samples of poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVDF) and melt blended PMMA/PVDF with weight ratios 4/1 and 3/2 were characterized by thermally stimulated depolarization currents (TSDC) in the temperature interval 123-303 K and by dielectric relaxation spectroscopy (DRS) in the frequency window 10−2 − 106 Hz in the temperature interval 153-423 K. The TSDC thermograms and DRS profiles of the samples showed the two types of conducnivity – non-cooperative and cooperative. The experimental DRS data in the vicinity of the glass transition temperature, Tg, were quantitatively fitted to the Havriliak-Negami function and values of the maximum relaxation time were fitted to the Vogel-Tammann-Fulcher equation. Higher values of the strength index D, of the dielectric relaxation strength Δε and of the σ ac conductivity for the binary blends were considered as experimental evidence for nanoscale composition heterogeneities originating from strong specific interactions between the PMMA and PVDF. Therefore, we suggest the PMMA/PVDF blends will be usefull as effective materials for the manufacture of lithium-ion batteries, electrostatic capacitors with superior energy storage performance, polymer composite electrolytes for solar cells, etc.

Longitudinal spin relaxation time of donor-bound electrons in a CdTe quantum well

We study the magnetic-field dependence of the longitudinal spin relaxation time ${T}_{1}$ of donor-bound electrons placed in the middle of an 8-nm CdTe quantum well with different doping concentrations in the range from $1\ifmmode\times\else\texttimes\fi{}{10}^{9}$ to $2.9\ifmmode\times\else\texttimes\fi{}{10}^{11}$ $\mathrm{c}{\mathrm{m}}^{\ensuremath{-}2}$ and at low temperature. We use an extended photoinduced Faraday rotation technique, which expands the usual domain of the measured decays from tens of ns to $\ensuremath{\mu}\mathrm{s}$. As in high-purity bulk semiconductors, a maximum relaxation time of around ${T}_{1}\ensuremath{\sim}10\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s}$ is observed for a residually doped sample at low magnetic field of $B=0.08\phantom{\rule{0.16em}{0ex}}\mathrm{T}$. For higher doping concentrations, the magnetic-field dependence of ${T}_{1}$ shows a nonmonotonic behavior: first a rapid increase, followed by a plateau or a decrease of ${T}_{1}$. The fast increase of ${T}_{1}$ at low magnetic fields is explained by the inhibition of the mechanisms identified at zero field---hyperfine and anisotropic exchange interactions---while the behavior at high magnetic field can be succesfully explained by a mechanism proposed by Lyubinskiy and associated to electron hops [I. S. Lyubinskiy, JETP Lett. 88, 814 (2008)]. A good agreement between experiment and theory is found for samples below the metal-insulator transition, when Dresselhaus terms of spin-orbit coupling are considered to be the dominant ones in the Hamiltonian describing the system.

Dynamic Bonds Mediate π-π Interaction via Phase Locking Effect for Enhanced Heat Resistant Thermoplastic Polyurethane

Stimulus-responsive polymers containing dynamic bonds enable fascinating properties of self-healing, recycling and reprocessing due to enhanced relaxation of polymer chain/network with labile linkages. Here, we study the structure and properties of a new type of thermoplastic polyurethanes (TPUs) with trapped dynamic covalent bonds in the hard-phase domain and report the frustrated relaxation of TPUs containing weak dynamic bond and π-π interaction in hard segments. As detected by rheometry, the aromatic TPUs with alkyl disulfide in the hard segments possess the maximum network relaxation time in contrast to those without dynamic bonds and alicyclic TPUs. In situ FTIR and small-angle scattering results reveal that the alkyl disulfide facilitates stronger intermolecular interaction and more stable micro-phase morphology in π-π interaction based aromatic TPUs. Molecular dynamics simulation for pure hard segments of model molecules verify that the presence of disulfide bonds leads to stronger π-π stacking of aromatic rings due to both enhanced assembling thermodynamics and kinetics. The enhanced π-π packing and micro-phase structure in TPUs further kinetically immobilize the dynamic bond. This kinetically interlocking between the weak dynamic bonds and strong molecular interaction in hard segments leads to much slower network relaxation of TPU. This work provides a new insight in tuning the network relaxation and heat resistance as well as molecular self-assembly in stimulus-responsive dynamic polymers by both molecular design and micro-phase control toward the functional applications of advanced materials.

Dynamics of Confined Short-Chain alkanol in MCM-41 by Dielectric Spectroscopy: Effects of matrix and system Treatments and Filling Factor.

The dynamics of n-propanol confined in regular MCM-41 matrix with the pore size Dpore = 40 Å, under various matrix conditioning and sample confining conditions, using broadband dielectric spectroscopy (BDS), is reported. First, various drying procedures with the capacitor filling under air or N2 influence the BDS spectra of the empty MCM-41 and the confined n-PrOH/MCM-41 systems, but have a little effect on the maximum relaxation time of the main process. Finally, various filling factors of n-PrOH medium in the optimally treated MCM-41 system lead to unimodal or bimodal spectra interpreted in terms of the two distinct dynamic phases in the confined states.

Heat transfer enhancement and reduction in low-Rayleigh number natural convection flow with polymer additives

The effects of viscoelasticity, here caused by polymer additives, on Rayleigh Bénard convection flows are investigated via direct numerical simulations at a marginally turbulent Rayleigh number. Simulations with a range of polymer length and relaxation time scales show heat transfer enhancement (HTE) and reduction (HTR). The selection of HTE and HTR depends strongly on the maximum extensional viscosity of the solution, whereas the magnitude of heat transfer modification is a function of both the maximum extensional viscosity and relaxation time of the polymer solution. The underlying physics of HTE and HTR are explored, and a mechanism of the interaction between convection cells and polymers is proposed. The findings are extrapolated to high Ra to shed some new light onto experimental observations of HTR.

Pharyngeal Motility Before and After Thyroarytenoid Muscle Botulinum Toxin Injection.

Botulinum toxin type A (BTA) injection in intrinsic laryngeal musculature may result in dysphagia and consequent loss of quality of life (QOL) in a percentage of patients. This study aims to evaluate pharyngeal motility as a putative cause for this change in swallow quality in light of high-resolution manometry (HRM). Twenty patients (95% females, median age 66years) underwent high-resolution manometry before and after BTA injection. Dysphagia was evaluated based on a QOL dedicated questionnaire (SWAL-QOL) before and after BTA injection. Pharyngeal motility at the topography of the vellum, epiglottis, and upper esophageal sphincter (UES) were recorded. Eleven (55%) subjects had worsened QOL after BTA injection. In patients with worsened QOL, UES extension decreased (p = 0.005), UES residual pressure increased (p = 0.02), UES basal pressure decreased (p = 0.04), and velopharynx contraction duration decreased (p = 0.04). UES residual pressure increased (p = 0.01), velopharynx peak pressure (p = 0.04) and upstroke (p = 0.007) decreased in patients with maintained QOL. There was no difference between groups when comparing pre-injection values. UES extension (p = 0.01) and UES maximum relaxation time (p = 0.03) was lower in the group with worsened QOL after BTA as compared to no change in QOL. Pharyngeal motility as measured by HRM was not a predictor for post procedure dysphagia and the changes in motility after BTA injection does not seem to be a strong contributor to dysphagia.

Effects of percutaneous neuromodulation on the mechanical characteristics of the rectus femoris and the vastus lateralis in football players: a pilot study

Abstract Background and Aims Percutaneous neuromodulation is an ultrasound-guided technique aimed at the peripheral nerve, using an acupuncture needle as an electrode for a TENS type current which has demonstrated to have positive effects for pain but not for muscle activity. Tensiomyography (TMG) is a non-invasive assessment technique, which is reliable and provides instant information on the mechanical characteristics of superficial muscles. The aim of this study is to evaluate whether percutaneous neuromodulation produces effects on muscle contraction parameters. Material and Methods A longitudinal, analytic and experimental study with a control group, comprising a sample of 11 football players in the 3rd Division, randomly assigned to an intervention group (IG = 5) and a control group (CG = 6). Athletes were assessed using tensiomyography (TMG-S2, EMF-FURLAN & Co.) parameters: maximum deformation (Dm), response time (Td), contraction time (Tc), relaxation time (Tr) and time of contraction maintenance (Ts) of the rectus femoris (RF) and vastus lateralis (VL). Both legs were assessed immediately after the training session (Pre), after 10' rest period post intervention (Post1) and after 12 hours of rest on the following day (Post2). Both femoral nerves were intervened with a needle on the long axis and in a transverse section just below the same. An Electrostimulator (ITO, model ES- 160), was applied to the IG during 5' using a TENS current of 200µs, 1 Hz and with sufficient intensity to achieve a visible contraction of the quadriceps without discomfort. The channel was closed with adhesive electrodes placed medial to the ASIS. The CG received a placebo treatment with needles and electrodes placed on the same anatomical points and connected to an electrostimulator without current during 5' (Physio Invasiva device). Results On the right RF the Td decreased in the IG (pre/post2: P = 0.005) and between groups (post1: P = 0.017 and post2: P = 0.014). For Tc we found differences between the IG (pre/post2: P= 0.008) and the CG (post1/post2: P = 0.019). The left RF increased Tc in the CG (P = 0.036) and pre/post2 and Ts in the CG compared to the IG (post2: P = 0.0480.048). In the left VL Dm increased (pre/post2: P = 0.046 and post1/post2: P = 0.018), Td (pre/post2: P = 0.010) and Tc (pre/post2: P = 0.051 and post1/post2: P = 0.003) for the CG. In the IG, the right VL, both Td (P = 0.024) and Tc (P = 0.021) decreased between post1/post2. For the intragroup analysis (pre, post1 and post2) the Student's t-test was used, whereas for the intragroup analysis, the ANOVA was used (significance > P 0.05). Conclusions Considering the characteristics of the sample and understanding that the decrease of TMG parameters represents an improvement in the mechanical characteristics of the muscle, the findings of this pilot study suggest that the intervention with percutaneous neuromodulation in the IG produces greater recovery and improved activation after 12 hours on the RF and VL. However, the increase of these parameters in the CG results in greater fatigue.