Hz Frequency Research Articles

Spontaneous slow cortical potentials and brain oscillations independently influence conscious visual perception.

Perceptual awareness results from an intricate interaction between external sensory input and the brain's spontaneous activity. Pre-stimulus ongoing activity influencing conscious perception includes both brain oscillations in the alpha (7 to 14 Hz) and beta (14 to 30 Hz) frequency ranges and aperiodic activity in the slow cortical potential (SCP, <5 Hz) range. However, whether brain oscillations and SCPs independently influence conscious perception or do so through shared mechanisms remains unknown. Here, we addressed this question in 2 independent magnetoencephalography (MEG) data sets involving near-threshold visual perception tasks in humans using low-level (Gabor patches) and high-level (objects, faces, houses, animals) stimuli, respectively. We found that oscillatory power and large-scale SCP activity influence conscious perception through independent mechanisms that do not have shared variance. In addition, through mediation analysis, we show that pre-stimulus oscillatory power and SCP activity have different relations to pupil size-an index of arousal-in their influences on conscious perception. Together, these findings suggest that oscillatory power and SCPs independently contribute to perceptual awareness, with distinct relations to pupil-linked arousal.

Seismic response and damage model analysis of rocky slopes with weak interlayers

Abstract A large-scale shaking table test of an anti-dip rock slope with a weak interlayer is conducted based on the Hongshiyan landslide induced by the Ludian earthquake. The dynamic failure mode energy damage identification method is analyzed using the Hilbert–Huang transformation and marginal spectrum theory. The result shows that the weak interlayer under horizontal loading amplifies the 5–10 and 25–30 Hz frequency signal and attenuates the 15–20 Hz signal. Within the hard rock, it amplifies the 5–15 Hz frequency signal and attenuates the 20–30 Hz signal. Under vertical loading, both weak interlayer and hard rock have an amplification effect on 5–30 Hz signal, and the amplification effect of weak interlayer is more significant. The horizontal seismic wave slope damage process can be divided into two stages: internal damage and obvious failure. When the horizontal seismic input amplitude reaches 0.2–0.3 g, internal damage occurs in the slope. The slope damage is primarily concentrated below two-third of the hard rock height and primarily in the shallow and surface regions of the slope. An input amplitude in the range of 0.4–0.5 g corresponds to the obvious failure stage. At this time, the slope first undergoes an obvious rupture in the rock above the weak layer; this rupture then extends upward to the top of the slope. Marginal spectral analysis results are consistent with the field model slope macroscopic rupture phenomenon.

Analysis of Environmental Vibrations in Suburban Railways Affected by Adjacent Bidirectional Tunnels

Train-induced environmental vibrations are a common issue in urban rail transit systems, particularly in suburban railways operating at high speeds, where the impact of these vibrations is more pronounced. This presents significant challenges for urban planners and engineers. Existing research has mainly focused on the impact of single tunnel structures on ground vibrations, with limited understanding of the vibration propagation characteristics of adjacent bidirectional tunnels. To address this gap in knowledge, this study investigates the ground vibration attenuation characteristics induced by train operations in the underground sections of suburban railways, with a focus on the amplification effects of adjacent tunnels on ground vibrations. The results show that the vibrations induced by the trains are concentrated in the 20–50 Hz frequency range and exhibit similar characteristics in all directions. The maximum vertical vibration acceleration and peak acceleration occur directly above the train tunnel. Additionally, adjacent tunnels significantly amplify the maximum peak acceleration at measurement points in directions perpendicular to the track, including both horizontal and vertical directions. Furthermore, the soil within the adjacent tunnels also exhibits amplification of the vertical power spectral amplitude in the 40–100 Hz frequency range. The findings of this study provide new insights into the influence of adjacent bidirectional tunnels on environmental vibrations in suburban railway operations. These results are of significant importance for optimizing railway design and vibration mitigation measures.

Novelty in Modifing the Weibull Distribution by Using Fast Fourier Transformation for Wind Energy Assessment

Wind energy considered to be the most recent source of power that inexpensive, non-depleting, also simple for a variety of users to capture and employ. The location of Ali El Gharbi is one of the preferable sites for clean energy production in Iraq, however as there is a lack of information about the power exploration potentials at this place, more related researches and studies for wind power wind are fundamental. An accurate comprehension for the behaviour of the wind is required for the preparation and operation of every wind conversions to energy project. The study is aimed at investigating the novelty in modifying the Weibull distribution by means of the Fast Fourier Transform with the purpose of estimate the possibility of wind energy harvesting in Ali El-Gharbi area of Ammarah, Iraq. The results from the modification of the Weibull distribution was a reduction in the value of the shape parameter for the new Weibull distribution which will lead to a smoother curve, the reduction of the shape parameter from about 5 to 1 implies a shift from the scenario where failures occur randomly and independently of the parameter. A second benefit of the modification was a reduction the time for calculation the Weibull parameters and PDF’s with increasing the accuracy. As an outcome of the wind speed data values were recorded at a 10-minutes interval for a year starting from December 2014 till December 2015 at heights of 10, 30, and 50 meters. Subsequently, the datasets were examined by means of the Weibull probability distribution function (WPD) to assess wind energy production, and for the spectral part of the analysis was conducted by employing the Fast-Fourier-Transform. According to the spectral analysis for the data, the average yearly wind speed at 50 m was 6.134 m/sec, whereas highest wind speed recorded there during the day were about 17.011 , and the peak wind speed was 226236.282 m/sec/12hour at a frequency(2 Hz) at that height of 50 m all through night hours. And for lowest values of wind speed was about 115863.7 m/sec/12hour for the (2 Hz) frequency at that height throughout night hours. The blowing of wind was more rapidly in the morning than it was at night periods. While the main wind directions in the region were from the north-northwest and west-northwest.

Hearing loss rather than vestibular loss identifies patient subgroups with different outcomes in Meniere’s disease

Objective This study investigates the relationship between Meniere’s disease (MD) duration and both hearing thresholds and vestibular dysfunction. Design Retrospective cohort study. First, the relationships between MD duration and pure-tone audiometry thresholds for each frequency, the canal paresis (CP) ratio, and the vestibulo-ocular reflex (VOR) gain were analysed. Second, clinical characteristics, CP values, and VOR gains were compared between patient groups with low and high hearing thresholds to determine whether they exhibited different clinical presentations. Study sample The study included 69 patients diagnosed with unilateral MD within a duration of 10 years. A hearing dataset from 306 MD Spanish patients was used to cluster patients according to the hearing profile overtime. Results The thresholds at 250–2000 Hz frequencies increased with the duration of the disease. Conversely, vestibular function tests were not related to the duration of MD. Additionally, no statistically significant differences were observed in clinical characteristics, CP values, or VOR gain between patient groups with low and high hearing thresholds. Conclusions Hearing loss involves all frequencies in most patients and hearing outcome, rather than vestibular loss, may define patient subgroups in MD. Moreover, not all patients with MD experience hearing loss progression as the duration of the disease increases.

Effectiveness of earthquake drains in mitigating liquefaction-induced settlement

This study evaluates the effectiveness of earthquake drains in mitigating liquefaction and examines their performance at specific frequencies in loose and medium-dense sediments. Two lab-scale shake table single-axis test series were conducted to assess this: one without mitigation and another using earthquake drains. Both models were instrumented and subjected to consistent shaking sequences at 1 Hz and 1.2 Hz frequencies. The results revealed reduced excess pore-water pressure generation around the drains due to the rapid dissipation of pore pressures during shaking. Additionally, the excess pore water pressure increased more slowly with the drains, as they allowed partial dissipation of pressure through drainage. Earthquake drains significantly reduced liquefaction potential, particularly in the middle area, where conditions shifted from liquefied to non-liquefied. Furthermore, ground treated with drains exhibited less differential settlement than untreated ground. The use of drains resulted in settlements being retrieved by 2% to 15% more than untreated conditions. The drains effectively mitigated the post-shaking liquefaction-induced settlement mechanisms. While this study demonstrates earthquake drains as a reliable and efficient measure for reducing liquefaction-induced settlement, further research is necessary to optimize their design and application.

Spontaneous oxycodone withdrawal disrupts sleep, diurnal, and electrophysiological dynamics in rats.

Opioid dependence is defined by an aversive withdrawal syndrome upon drug cessation that can motivate continued drug-taking, development of opioid use disorder, and precipitate relapse. An understudied but common opioid withdrawal symptom is disrupted sleep, reported as both insomnia and daytime sleepiness. Despite the prevalence and severity of sleep disturbances during opioid withdrawal, there is a gap in our understanding of their interactions. The goal of this study was to establish an in-depth, temporal signature of spontaneous oxycodone withdrawal effects on the diurnal composition of discrete sleep stages and the dynamic spectral properties of the electroencephalogram (EEG) signal in male rats. We continuously recorded EEG and electromyography (EMG) signals for 8 d of spontaneous withdrawal after a 14-d escalating-dose oxycodone regimen (0.5-8.0 mg/kg, 2×d; SC). During withdrawal, there was a profound loss (peaking on days 2-3) and gradual return of diurnal structure in sleep, body temperature, and locomotor activity, as well as decreased sleep and wake bout durations dependent on lights on/off. Withdrawal was associated with significant alterations in the slope of the aperiodic 1/f component of the EEG power spectrum, an established biomarker of arousal level. Early in withdrawal, NREM exhibited an acute flattening and return to baseline of both low (1-4 Hz) and high (15-50 Hz) frequency components of the 1/f spectrum. These findings suggest temporally dependent withdrawal effects on sleep, reflecting the complex way in which the allostatic forces of opioid withdrawal impinge upon sleep and diurnal processes. These foundational data based on continuous tracking of vigilance state, sleep stage composition, and spectral EEG properties provide a detailed construct with which to form and test hypotheses on the mechanisms of opioid-sleep interactions.

Low-noise laser intensity noise evaluation system at Hz frequency band for ground-based gravitational wave detection

The direct detection of gravitational waves has opened a new window for understanding the universe and trailblazed multi-messenger astronomy. The frequency band of gravitational waves generated by various astronomical events can cover broadband range, and it is various for detection mechanism and scheme of gravitational waves in different frequency band. For example, The ground-based gravitational wave detection has the frequency band for 10 Hz to 10 kHz to mainly detect which based on Michelson interferometer; The space gravitational wave detection has the frequency band of 0.1 mHz to 1 Hz to mainly detect which based on space interferometer; The pulsar gravitational wave detection has the frequency band for 1×10&lt;sup&gt;-9&lt;/sup&gt; Hz to 1×10&lt;sup&gt;-7&lt;/sup&gt;Hz to mainly detect which based on pulsar timing array. The next generation ground-based gravitational wave project demands higher sensitivity to detect faint signals, necessitating an assessment system with minimal background noise to accurately measure the laser relative intensity noise. At present, the detection frequency band of ground-based gravitational wave detection devices in operation is mainly concentrated in the range of 10 Hz - 10 kHz. To satisfying the detection sensitivity requirements, the laser relative intensity noise should be accurately evaluated and suppressed to ≤2.0×10&lt;sup&gt;-9&lt;/sup&gt;Hz&lt;sup&gt;-1/2&lt;/sup&gt;@10 Hz and ≤4.0×10&lt;sup&gt;-7&lt;/sup&gt;Hz&lt;sup&gt;-1/2&lt;/sup&gt;@10 kHz by photoelectric feedback. This paper constructed an evaluation and characterization system for ground-based gravitational wave band laser intensity noise which based on low noise and high sensitivity photoelectric detection device and combined with LabVIEW and MATLAB algorithm programming for instrument control and data processing. This low noise evaluation system is used to test the background noise of FFT analyzer SR760, preamplifier SR560, photoelectric detector electronics noise and intensity noise of self-developed optical fiber amplifier, and then the data extraction and image processing are carried out by LabVIEW and MATLAB algorithms, and finally the evaluation of ground-based gravitational wave frequency band system is obtained. The experimental results show that the whole electronic noise for the preamplifier SR560 and FFT analyzer SR760 is lower than 3.8×10&lt;sup&gt;-9&lt;/sup&gt; Hz&lt;sup&gt;-1/2&lt;/sup&gt;@(10 Hz-10 kHz). The electronic noise for the photodetector is lower than 1.4×10&lt;sup&gt;-8&lt;/sup&gt;V/√Hz@10 Hz&amp;8.1×10&lt;sup&gt;-9&lt;/sup&gt;V/√Hz@10 kHz and the accuracy of the system is calibrated and tested by the standard sinusoidal signal. Finally, the noise of commercial laser is evaluated and compared with the factory data to verify the accuracy of the evaluation system. Related research, device and system development provide hardware, software and theoretical basis for the preparation of high-power low-noise laser light source and gravitational wave detection and provide theoretical basis and evaluation criteria for ground-based gravitational wave detection in China.

Feasibility of Using Pulsed Electromagnetic Field Therapy to Improve the Dynamic Postural Balance of Children with Cerebral Palsy: A Randomized, Sham-Controlled Pilot Study

Cerebral palsy (CP) manifests with abnormal posture and impaired selective motor control, notably affecting trunk control and dynamic balance coordination, leading to inadequate postural control. Previous research has indicated the benefits of pulsed electromagnetic field (PEMF) therapy for various musculoskeletal and neurological conditions. Therefore, we conducted a randomized pilot study to assess the feasibility of our preliminary research design and examine the effect of the PEMF treatment among children with CP. Methods: Twelve children with spastic CP participated, with the study group undergoing PEMF treatment three times a week for four weeks. The treatment involved sine signal form, 20/200 Hz frequencies at an amplitude of 150 μT, initially administered for 8, 12, and 16 min per session. The control group received a sham treatment. Dynamic postural balance was evaluated using a force platform at baseline and post-intervention, and the data were analyzed. Data were processed using IBM SPSS 27 by repeated factorial analysis of variance. The significance level was α = 0.05. Results: No side effects of PEMF therapy were detected; this is important, because this intervention has not yet been applied among CP patients. The treatment group demonstrated a positive trend in fine balance coordination tests (p = 0.049); however, the small sample size and variability in control group performance suggest caution in interpreting these findings. Other test domains did not show significant differences. Conclusion: Our pilot study reveals the safety, feasibility, and potential efficacy of pulsed electromagnetic field (PEMF) therapy for children with cerebral palsy. With no observed side effects, the significant improvement in fine balance coordination suggests a promising avenue.

Control of a quasi-static MEMS Mirror for raster scanning projection applications

The angular motion of quasi-static micromirrors used for raster scanning projection applications is typically affected by undesired oscillations related to high-frequency resonant modes triggered by the sawtooth-like driving signal. This paper proposes a novel closed-loop tracking controller for improving the linearity of the trace motion, and hence the image brightness. It includes a feedforward action to achieve the required tracking performance under nominal conditions, and a feedback control for robustness against disturbances and other nonidealities. Notch filtering prevents resonance-induced ringing. The simplicity of the architecture enables an easy implementation on FPGA or ASIC. Experimental tests carried out on two different micromirrors with Lead-Zirconate-Titanate (PZT) piezoelectric actuation and piezoresistive sensing demonstrate an average linearity of 0.12 % and reproducibility of 15 mdeg for sawtooth reference trajectories with up to 8 deg amplitude and 120 Hz frequency, thus meeting the performance requirements mandated by the standards for high-resolutions projection applications.

An ultra low frequency spike timing dependent plasticity based approach for reducing alcohol drinking

Alcohol use disorder (AUD) is a chronic relapsing brain disorder characterized by an impaired ability to stop or control alcohol consumption despite adverse social, occupational, or health consequences. AUD affects nearly one-third of adults at some point during their lives, with an associated cost of approximately $249 billion annually in the U.S. alone. The effects of alcohol consumption are expected to increase significantly during the COVID-19 pandemic, with alcohol sales increasing by approximately 54%, potentially exacerbating health concerns and risk-taking behaviors. Unfortunately, existing pharmacological and behavioral therapies for AUD are associated with poor success rates, with approximately 40% of individuals relapsing within three years of treatment.Pre-clinical studies have shown that chronic alcohol consumption leads to significant changes in synaptic function within the dorsal medial striatum (DMS), one of the brain regions associated with AUD and responsible for mediating goal-directed behavior. Specifically, chronic alcohol consumption has been associated with hyperactivity of dopamine receptor 1 (D1) medium spiny neurons (MSN) and hypoactivity of dopamine receptor 2 (D1) MSNs within the DMS. Optogenetic, chemogenetic, and transgenic approaches have demonstrated that reducing the D1/D2 MSN signaling imbalance decreases alcohol self-administration in rodent models of AUD.Here, we present an electrical stimulation approach that uses ultra-low (≤ 1 Hz) frequency (ULF) spike-timing-dependent plasticity (STDP) in mouse models of AUD to reduce DMS D1/D2 MSN signaling imbalances by stimulating D1-MSN afferents into the GPi and ACC glutamatergic projections to the DMS in a time-locked stimulation sequence. Our data suggest that GPi/ACC ULF-STDP selectively decreases DMS D1-MSN hyperactivity leading to reduced alcohol consumption without evoking undesired affective behaviors using electrical stimulation rather than approaches requiring genetic modification. This work represents a step towards fulfilling the unmet need for a reliable method of treating severe AUD through cell-type-specific control with clinically available neuromodulation tools.

Eco-Friendly, Sound Absorbing Materials Based on Cellulose Acetate Electrospun Fibers/Luffa Cylindrica Composites.

Sound absorption plays a crucial role in addressing noise pollution that may cause harm to both human health and wildlife. To tackle this environmental issue, the implementation of natural-based sound absorbing materials attracts considerable attention in the last few years. In this study, sound absorbing, eco-friendly composites are produced by combining a 3D natural sponge namely Luffa Cylindrica (LC) with cellulose acetate (CA) microfibrous layers that are fabricated through electrospinning. Electrospun microfibers can effectively absorb sound waves due to their unique properties such as high porosity, small diameter, and large surface area. The individual components and the resulting composites, exhibiting various configurations, are characterized in respect to their morphology, porosity, density, and sound absorption properties. More precisely, the sound absorption coefficient is determined through the standing wave ratio method within the range of 500-4000 (Hz) frequency. The most promising materials consist of a multilayer combination of LC with CA microfibrous layers, which creates new prospects in the development of such materials for sound absorption applications.

Vibration characteristics of CFRP sandwich panels with acoustic black hole structures

An acoustic black hole, as a structure with a continuous gradient of thickness, has a good aggregation effect for bending waves. This paper introduces a novel carbon fiber reinforced plastic (CFRP) acoustic black hole sandwich structure. This structure comprises a CFRP panel and an acoustic black hole core layer, leveraging the aggregation effect of acoustic black holes to achieve vibration damping in low-frequency bands. Initially, the vibration transfer characteristics of acoustic black hole beams are examined based on the acoustic black hole effect. Subsequently, the influence of material, structure, and the number of acoustic black holes within the sandwich structures on their vibration transfer characteristics is investigated. Finally, the vibration characteristics of the CFRP sandwich structures are experimentally tested. The results indicate that the vibration transmission curve of the acoustic black hole beam exhibits multiple attenuation intervals within the 0-1200 Hz frequency range. Moreover, by adjusting the material and structural parameters of the core layer, the vibration bandgap of the sandwich structure can be shifted to the low-frequency region.

Персональная динамика отношения максимумов спектральных плотностей мощности альфа/дельта ритмов пациентов для оценки времени начала развития отсроченной церебральной ишемии после субарахноидального кровоизлияния

To assess the time of onset of delayed cerebral ischemia after subarachnoid hemorrhage, an approach based on personal dynamics of the ratio of the maximums of spectral densities of alpha/delta electroencephalogram rhythms in the data of long-term electroencephalographic monitoring was proposed and tested on clinical data. In contrast to the currently accepted estimation of the index based on alpha (8–13 Hz) and delta (1–4 Hz) frequency ranges averaged over the frequency ranges of rhythm powers. The proposed method is based on the calculation of the ratio of the maxima of the spectral power density in the frequency bands of alpha and delta rhythms using the calculation of Fourier spectra with a Hamming window of 3 hours. It is shown that the dynamics of the index of the ratio of maxima of spectral power densities of alpha/delta rhythms reflects the dependence of the development of delayed cerebral ischemia on a steady decrease in the index ten times more than in control patients. The results reflecting the interhemispheric asymmetry of the dynamics of the ratio of the maxima of spectral densities of alpha/delta rhythm power in patients with diagnosed delayed ischemia are presented.

Changes in physico-chemical and functional properties of liquid egg white by ohmic heating process

In the present study, ohmic heating system was developed for the pasteurization of liquid egg white. A batch reactor system was designed with a capacity of 100 ml and operated at varied gradients of voltage (20, 15, 10 V/cm), frequencies (10, 55, 100 Hz), holding times (1, 2.5, 4 min) at two different waveforms (sine and square). The treated liquid egg white was evaluated for validation parameters viz., heating rate, turbidity, soluble protein content, foaming capacity, and foaming stability. The viscosity of ohmically treated egg white was observed by subjecting the egg white to the shear rate ranges from 0.167 to 68 (s−1) where the viscosity decreased as the shear rate increased. The ohmic heating process variables were optimized using the Box-Behnken design and had a significant effect (P < 0.005) on the responses. The optimized parameters 17.93 V/cm voltage gradient, 10 Hz frequency, and 1.6 min holding time for sine waveform resulted in 19.6 °C/min heating rate, 0.01 turbidity, 98.35% soluble protein, 405.68% foaming capacity, and 31.84% foaming stability with the highest desirability of 78% of liquid egg white. The model developed from the dataset of this design can be used for predicting the responses within the limits of process variables.

Preparation and Characterization of Injectable Augmentation Gels Containing Polycaprolactone and Hyaluronic Acid.

Injectable augmentation gels are widely used in the treatment of soft tissue. The composition of these gels has to be continuously improved due to the limitations of the currently available formulations. This study focuses on the development of an innovative injectable gel designed to address current trends and specific needs within the field. The current study utilized a safer hyaluronic acid (HA) gel carrier, created with a less toxic cross-linker, in combination with polycaprolactone (PCL) microspheres at various concentrations. PCL microspheres were prepared using an emulsification-solvent evaporation technique. Six different gel formulations were developed using PCL microspheres and biphasic HA gel structures. The produced microspheres had non-agglomerated, smooth surfaces with an average particle size of approximately 45 ± 0.14 μm. The rheological results of the PCL-HA6 such as storage modulus (G', Pa), loss modulus (G", Pa), complex viscosity (η*), and phase angle (°) at 1 Hz frequency were measured as 553.97 ± 32.48, 368.4 ± 12.24, 105.9 ± 5.27, and 33.65 ± 0.92, respectively, and the injection force was measured as 9.64 ± 1.46. Invitro tests revealed that the PCL-HA6 group showed the highest cell viability compared to the other groups and provided a relative increase in collagen production over time, as demonstrated by the relevant gene expression. The developed PCL/HA gel exhibited biocompatibility and non-toxicity, making it a safe option for soft tissue augmentation. It demonstrated potential for medical applications and exhibited favorable rheological characteristics and injectability.

Forearm Bio-Medical Signal Processing

This research utilizes low-dimensional surface EMG and EEG data, obtained from the human arm using ECG electrodes, to analyze forearm muscle signals through a novel approach. Both EMG and EEG signals are employed side by side: EEG captures brain activity, particularly in the beta (13-30 Hz) and alpha (8-12 Hz) frequency ranges, while EMG focuses on muscle activity in the 20 Hz to 200 Hz range. Beta waves are associated with motor planning and voluntary movements, while alpha waves decrease during movement execution, indicating disengagement from a resting state. Event-related desynchronization (ERD) of alpha and beta waves is vital in understanding motor tasks, including forearm movements. Although EEG alone showed a poor response in tracking movement execution, EMG provided better performance, with higher frequencies reflecting more intense muscle contractions and motor unit activation. The combination of EEG and EMG improves the analysis of event-related potentials (ERPs) in timing tasks, enabling precise monitoring of both brain and muscle activity. However, coordinating both signals can be complex and often relies on user experience. Extensive experimentation confirms that using this dual approach is feasible and effective in replicating natural arm movements. The findings highlight important advancements in applying signal processing techniques to muscle activity analysis, providing new insights into the control of muscles and enhancing accessibility to modern assistive technologies.

Acute sport-related concussion alters cardiac contribution to cerebral oxygenation during repeated squat stands

ABSTRACT Assessment of cerebral oxygenation during repeated squat stands following an acute sport-related concussion (SRC) has the potential to identify physiological changes following SRC. All varsity university athletes completed a pre-season assessment and 53 were followed up within 5-days of suffering an SRC. Of the 53 participants, 29 had continuous beat-to-beat blood pressure (BP; sampled at 200 hz) collected by finger photoplethysmography, and 53 had right prefrontal cortex oxygenation collected by near-infrared spectroscopy (NIRS; sampled at 10 hz). Participants completed a 5-min repeated squat (10 s) stand (10 s) manoeuvre (0.05 hz). Wavelet transformation was applied to the signals, separating them into smooth muscle cell (0.05 to 0.145 hz), respiratory (0.145 to 0.6 hz) and cardiac (0.6 to 2 hz) frequency intervals, with the 5-min squat stand manoeuvre compared from pre-season to post-concussion. A significant amplitude increase (p < 0.05) in oxyhaemoglobin, total haemoglobin and haemoglobin difference following SRC was found at the cardiac interval. During the squat stand dynamic cerebral autoregulation challenge, this exploratory study found an elevated contribution from the heart to the oxygenation response at the right prefrontal cortex, suggestive of a cardiac compensatory response during concussion. Future research with cerebral blood flow alongside NIRS can provide greater insight to dynamic cerebral autoregulation.

Experimental validation of a wave-height sensor based on a MEMS piezoresistive cantilever and a waterproof film

Abstract This paper presents a barometric pressure-sensing wave-height sensor that employs a microelectromechanical system (MEMS) piezoresistive cantilever, an air chamber, and a micromesh waterproof film. The developed sensor has a height resolution of less than 5 mm in the 0.01–10 Hz frequency band and a high time resolution with 100 Hz sampling rate. We conducted wave height measurements at sea using the developed sensor and compared its performance with that of a commercial GPS buoy-type wave-height sensor.

Mechanical Stretch Control of Adipocyte AKT Signaling and the Role of FAK and ROCK Mechanosensors.

Adipose tissue in vivo is physiologically exposed to compound mechanical loading due to bodyweight bearing, posture, and motion. The capability of adipocytes to sense and respond to mechanical loading milieus to influence metabolic functions may provide a new insight into obesity and metabolic diseases such as type 2 diabetes (T2D). Here, we evidenced physiological mechanical loading control of adipocyte insulin signaling cascades. We exposed differentiated 3T3-L1 adipocytes to mechanical stretching and assessed key markers of insulin signaling, AKT activation, and GLUT4 translocation, required for glucose uptake. We showed that cyclic stretch loading at 5% strain and 1 Hz frequency increases AKT phosphorylation and GLUT4 translocation to the plasma membrane by approximately two-fold increases compared to unstretched controls for both markers as assessed by immunoblotting (p < 0.05). These results indicate that cyclic stretching activates insulin signaling and GLUT4 trafficking in adipocytes. In the mechanosensing mechanism study, focal adhesion kinase (FAK) inhibitor (FAK14) and RhoA kinase (ROCK) inhibitor (Y-27632) impaired actin cytoskeleton structural formation and significantly suppressed the stretch induction of AKT phosphorylation in adipocytes (p < 0.001). This suggests the regulatory role of focal adhesion and cytoskeletal mechanosensing in adipocyte insulin signaling under stretch loading. Our finding on the impact of mechanical stretch loading on key insulin signaling effectors in differentiated adipocytes and the mediatory role of focal adhesion and cytoskeleton mechanosensors is the first of its kind to our knowledge. This may suggest a therapeutic potential of mechanical loading cue in improving conditions of obesity and T2D. For instance, cyclic mechanical stretch loading of adipose tissue could be explored as a tool to improve insulin sensitivity in patients with obesity and T2D, and the mediatory mechanosensors such as FAK and ROCK may be targeted to further invigorate stretch-induced insulin signaling activation.