Significant Changes In Amplitude Research Articles

Global sensitivity analysis of water level response to harmonic aquifer disturbances through a Monte-Carlo based surrogate model with random forest algorithm

Oscillatory water levels are often observed in monitoring wells, when aquifers are disturbed by periodical pressure diffusion (PD) sources, such as oscillatory pumping and ocean tide, and by volumetric strain (VS) sources including the far-field seismic wave and earth tide. The measured water level responses are extensively utilized to interpret aquifer properties and seismic hydrological phenomena. However, owing to wellbore effects, water levels are not always truly representative of pore pressure in aquifers, and can be significantly attenuated or even unobservable in wells. To clarify how water level responds to these disturbances, this study analyzes a global parameter sensitivity of the coupled well-aquifer model based on the assumption of a confined homogeneous aquifer. Parameter uncertainties concerning aquifer properties, source characteristics, and wellbore construction are first analyzed separately for the PD and VS sources. Subsequently, Monte-Carlo based surrogate models linking parameters and response indices are developed using the random forest algorithm. For the PD source, sensitivity results indicate that hydraulic conductivity is the most influential parameter for the yes/no responses. When hydraulic conductivity exceeds 10-4 m/s, water level observations basically represent pore pressure in aquifers. Significant amplitude changes and phase delay occur when the period of disturbances is less than 50 s, majorly due to water column inertia. For VS sources, water level responses are typically observed in aquifers with hydraulic conductivity larger than 10-7 m/s and when disturbed by a source with amplitude greater than 10-3 MPa. However, pronounced amplitude changes and phase shifts occur when the source period varies within 100 s. Consideration of the impact of wellbore effects is recommended, when interpreting water level responses induced by all periodic aquifer disturbances, especially in low-conductivity aquifers with conductivities less than 10-4 m/s.

Acute Metabolic Stress Induces Lymphatic Dysfunction through KATP Channel Activation.

Lymphatic dysfunction is an underlying component of multiple metabolic diseases, including diabetes, obesity, and metabolic syndrome. We investigated the roles of KATP channels in lymphatic contractile dysfunction in response to acute metabolic stress induced by inhibition of the mitochondrial electron transport chain. Ex vivo popliteal lymphatic vessels from mice were exposed to the electron transport chain inhibitors antimycin A and rotenone, or the oxidative phosphorylation inhibitor/protonophore, CCCP. Each inhibitor led to a significant reduction in the frequency of spontaneous lymphatic contractions and calculated pump flow, without a significant change in contraction amplitude. Contraction frequency was restored by the KATP channel inhibitor, glibenclamide. Lymphatic vessels from mice with global Kir6.1 deficiency or expressing a smooth muscle-specific dominant negative Kir6.1 channel were resistant to inhibition. Antimycin A inhibited the spontaneous action potentials generated in lymphatic muscle and this effect was reversed by glibenclamide, confirming the role of KATP channels. Antimycin A, but not rotenone or CCCP, increased dihydrorhodamine fluorescence in lymphatic muscle, indicating ROS production. Pretreatment with tiron or catalase prevented the effect of antimycin A on wild-type lymphatic vessels, consistent with its action being mediated by ROS. Our results support the conclusion that KATP channels in lymphatic muscle can be directly activated by reduced mitochondrial ATP production or ROS generation, consequent to acute metabolic stress, leading to contractile dysfunction through inhibition of the ionic pacemaker controlling spontaneous lymphatic contractions. We propose that a similar activation of KATP channels contributes to lymphatic dysfunction in metabolic disease.

Electric-field-dependent electrical properties and domain switching of 0.92BNT-0.08BT ceramic coatings

Bi0.5Na0.5TiO3-based ferroelectric materials with strong ferroelectricity and high Curie temperature have great application prospects in modern microdevices. In this paper, 0.92BNT-0.08BT ceramic coating was prepared by supersonic plasma spraying. The phase, microstructure, electrical properties and domain response of 0.92BNT-0.08BT ceramic coating were analyzed. The findings demonstrate that the 0.92BNT-0.08BT ceramic coating is without obvious structural defects and has a completely structure with good interface bonding. 0.92BNT-0.08BT ceramic coating has good electrical properties, the dielectric constant is 417, the dielectric loss is 0.3, and the remnant polarization is 16.6μC/cm2. The piezoelectric force microscopy (PFM) results show that the 0.92BNT-0.08BT ceramic coating generally exhibits irregular and inhomogeneous striped nanodomains, with significant changes in amplitude and phase response under different electric fields. The results using switching spectroscopy-piezoresponse force microscopy (SS-PFM) show that the local piezoelectric coefficient (PRmax) of the 0.92BNT-0.08BT ceramic coating reaches 754.3 pm/V at a voltage of 20 V, and the ferroelectric domains exhibit a clear switching behavior.

Changes in corticospinal excitability during motor imagery by physical practice of a force production task: Effect of the rate of force development during practice

Transcranial magnetic stimulation studies have indicated that the physical practice of a force production task increases corticospinal excitability during motor imagery (MI) of that task. However, it is unclear whether this practice-induced facilitation of corticospinal excitability during MI depends on a repeatedly practiced rate of force development (RFD). We aimed to investigate whether corticospinal excitability during MI of an isometric force production task is facilitated only when imagining the motor task with the same RFD as the physically practiced RFD. Furthermore, we aimed to examine whether corticospinal excitability during MI only occurs immediately after physical practice or is maintained. Twenty-eight right-handed young adults practiced isometric ramp force production using right index finger abduction. Half of the participants (high group) practiced the force production with high RFD, and the other half (low group) practiced the force production with low RFD. Questionnaire scores indicating MI ability were similar in the two groups. We examined the force error relative to the target force during the force production task without visual feedback, and motor evoked potential (MEP) amplitudes of the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles during the MI of the force production task under practiced and unpracticed RFD conditions before, immediately after, and 20 min after physical practice. Our results demonstrated that the force error in both RFD conditions significantly decreased immediately after physical practice, irrespective of the RFD condition practiced. In the high group, the MEP amplitude of the FDI muscle during MI in the high RFD condition significantly increased immediately after practice compared to that before, whereas the MEP amplitude 20 min after practice was not significantly different from that before practice. Conversely, the MEP amplitude during MI in the high RFD condition did not change significantly in the low group, and neither group had significant changes in MEP amplitude during MI in the low RFD condition. The facilitatory effect of corticospinal excitability during MI with high RFD observed only immediately after physical practice in the high RFD condition may reflect short-term functional changes in the primary motor cortex induced by physical practice.

Quantitative evaluation of the impact of variation of optical parameters on the estimation of blood hematocrit and oxygen saturation for dual-wavelength photoacoustics

Photoacoustic (PA) spectroscopy is considered to be one of the most effective ways to measure the levels of hematocrit (H) and oxygenation saturation (SO2) of blood, which are essential for diagnosing blood-related illnesses. This simulation study aims to investigate the impact of individual optical parameters, i.e., optical absorption coefficient (μ a ), scattering coefficient (μ s ), and anisotropy factor (g), on the accuracy of this technique in estimating the blood properties. We first performed the Monte Carlo simulations, using realistic optical parameters, to obtain the fluence maps for various samples. The wavelengths of the incident light were chosen to be 532, 700, 1000, and 1064 nm. Thereafter, the k-Wave simulations were executed, incorporating those fluence maps to generate the PA signals. The blood properties were obtained using the PA signals. We introduced variations in μ a , μ s , and g ranging from −10% to +10%, −10% to +10%, and −5% to +1%, respectively, at 700 and 1000 nm wavelengths. One parameter, at both wavelengths, was changed at a time, keeping others fixed. Subsequently, we examined how accurately the blood parameters could be determined at physiological hematocrit levels. A 10% variation in μ a induces a 10% change in H estimation but no change in SO2 determination. Almost no change has been seen for μ s variation. However, a 5% (−5% to 0%) variation in the g factor resulted in approximately 160% and 115% changes in the PA signal amplitudes at 700 and 1000 nm, respectively, leading to ≈125% error in hematocrit estimation and ≈14% deviation in SO2 assessment when nominal SO2=70%. It is clear from this study that the scattering anisotropy factor is a very sensitive parameter and a small change in its value can result in large errors in the PA estimation of blood properties. In the future, in vitro experiments with pathological blood (inducing variation in the g parameter) will be performed, and accordingly, the accuracy of the PA technique in quantifying blood H and SO2 will be evaluated.

Enhancing Sleep Quantity and Quality with a Novel GABAergic Dietary Supplement

Purpose: The primary objective of this investigation was to evaluate the effects of BH_SLP_01 (Bonafide Health Sleep Product) on sleep quality and brain wave patterns using a caffeine-induced insomnia model, and on sleep duration and latency using a pentobarbital-induced sleep model. Methods: Five male BALB/c mice were allocated per treatment arm (age: 8 weeks, body mass: 180 ± 20 g). Treatment arms included control, caffeine or phenobarbital (active) control, and BH_SLP_01. Caffeine treatment model. To induce sleep disturbance, 7.5 mg/kg caffeine was injected intraperitoneally at the 15th minute (min) of recordings, and second injections (saline or combinations) were performed at the 30th minute. Brain electrical activity was monitored and recorded for a total of two hours using electrocorticography (ECoG) recording. Serum melatonin, serotonin, and dopamine were measured by ELISA. Brain levels of MDA were measured by HPLC, and protein concentrations were determined using Western Blot analysis. Phenobarbital treatment model Groups were administered saline or BH_SLP_01, and then, 45 min later, pentobarbital (42 mg/kg) was injected. After injection, sleep latency and duration were measured. Study treatments were compared using an ANOVA and Student's unpaired t-test. Significance levels were set at p<0.05. Results: Analysis of ECoG recording data revealed notable findings. In the caffeine-pretreated group, a significant increase in amplitude was observed during the 30-45 min interval, compared to control. Caffeine administration also significantly increased frequency at 75-90 and 90-105 min compared to control (p<0.05). Conversely, the group treated with BH_SLP_01 displayed no significant changes in amplitude and frequency, except for a significant change in frequency at 90-105 min compared to control (p<0.05). Both sleep duration and sleep latency were significantly improved for BH_SLP_01 compared to control and phenobarbital control (p<0.05). In addition, serotonin, dopamine, melatonin, GABAA R2, GABAB R1, GABAB R2, 5-HT1A, GluA1, GluN1, GluN2A, Bax, Bcl-2, and Caspase-3 levels were significantly improved by BH_SLP_01 compared to control and caffeine control (p<0.05). Conclusion: The results of these studies provide evidence for the effcacy of BH_SLP_01 to improve impaired sleep, leading to notable enhancements in markers of deep sleep. This conclusion is supported by the significant upregulation of GABA, glutamine receptors, and endogenous melatonin, all of which collectively contribute to the augmentation of both sleep quantity and quality. These findings underscore the potential of BH_SLP_01 as a promising therapeutic intervention for optimizing sleep parameters and promoting overall sleep wellness. This research was supported by Bonafide Health, LLC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

In vitro effects of β3-adrenoceptor agonist mirabegron on the human ureter.

This study aimed to investigate the effect of mirabegron, a β3-adrenoceptor agonist with widespread clinical use for treating overactive bladder disease, on isolated healthy human ureter strips. This was a prospective study employing a series of in vitro organ bath experiments using ureteral tissues of kidney grafts from 10 healthy donors. The ureteral strips were subjected to cumulative mirabegron concentrations (10-9-10-4.5 M). Effects on frequency or amplitude of spontaneous, 10 mM KCl- or EFS-induced contractions were evaluated. Mirabegron decreased the frequency of spontaneous ureteric contraction in a concentration-dependent manner. Statistically significant decrease in the frequency of spontaneous contraction was observed at 10-8-10-4.5 M. In 10 mM KCl medium, statistically significant change in frequency was observed at 10-9-10-4.5 M. Statistically significant decrease in the amplitudes of spontaneous contraction was observed at 10-7-10-4.5 M. In a 10 mM KCl medium, statistically significant change in amplitudes was observed at 10-8-10-4.5 M. Mirabegron reduced the amplitude and frequency of human ureter activity in in vitro organ bath studies. This effect was achieved in a dose-dependent manner on isolated tissue strips. Although monotherapy with mirabegron remains uncertain, this study has the potential to elucidate the mechanism underlying the effectiveness of mirabegron, particularly in combination therapy for ureteral stones.

VLF Signal Noise Reduction during Intense Seismic Activity: First Study of Wave Excitations and Attenuations in the VLF Signal Amplitude

This study is a continuation of pilot research on the relationships between seismic activity and changes in very low frequency (VLF) signals starting a few minutes or a few dozen minutes before an earthquake. These changes are recorded in the time and frequency domains and their duration can be influenced not only by the strongest earthquake but also by others that occur in a short time interval. This suggests that there are differences in these changes in cases of individual earthquakes and during the period of intense seismic activity (PISA). In a recent study, they were validated in the time domain by comparing the amplitude noise reductions during the PISA and before earthquakes that occurred in the analysed periods without intense seismic activity (PWISA). Here, we analyse the changes in the VLF signal amplitude in the frequency domain during the PISA and their differences are compared to the previously investigated relevant changes during PWISA. We observe the signal emitted by the ICV transmitter in Italy and received in Serbia from 26 October to 2 November 2016 when 907 earthquakes occurred in Central Italy. The study is based on analyses of the Fourier amplitude AF obtained by applying the fast Fourier transform (FFT) to the values of the ICV signal amplitude sampled at 0.1 s. The obtained results confirm the existence of one of the potential earthquake precursors observed during PWISA: significantly smaller values of AF for small wave periods (they can be smaller than 10−3 dB) than under quiet conditions (the expected values are larger than 10−2 dB). Exceptions were the values of AF for wave periods between 1.4 s and 2 s from a few days before the observed PISA to almost the end of that period. They were similar or higher than the values expected under quiet conditions. The mentioned decrease lasted throughout the observed longer period from 10 October to 10 November, with occasional normalisation. It was many times longer than the decreases in AF around the considered earthquakes during PWISA, which lasted up to several hours. In addition, no significant wave excitations were recorded at discrete small values of the wave periods during the PISA, as was the case for earthquakes during PWISA. These differences indicate the potential possibility of predicting the PISA if the corresponding earthquake precursors are recorded. Due to their importance for potential warning systems, they should be analysed in more detail in future statistical studies.

Method and system for automated detection of sleep spindles using a single EEG channels based TEO and EMD

As a hallmark of N2 sleep stage, sleep spindle detection based on electroencephalogram (EEG) recordings plays a crucial role in analyzing sleep. Hence, how to effectively automatically detect sleep spindle is crucially important. However, many automatic detection methods assume that the signal is stationary, which is inconsistent with the observation that spindle signals have a significant change in amplitude. Thus, some important non-stationary information and the presented evident dynamic characteristics has been ignored.To overcome the aforementioned shortcoming, we propose a novel methodology based on Teager Energy Operator (TEO) and Empirical Mode Decomposition (EMD) to determine the exact location of sleep spindles using single-channel EEG signals. Because the TEO is sensitive to amplitude variations and energy features, our proposed method is suitable for capturing sleep spindles. We conduct plenty of experiments to evaluate our method. The experiments are conducted to validate the effectiveness of our method. On the DREAMS Sleep Spindles Database, our method achieves 91.83% ± 1.1%, 94.12% ± 3.46%, and 83.38% ± 9.32% for accuracy, specificity, and sensitivity, respectively. Experimental results show that the performance of the proposed methodology presented herein achieves better performance as compared to other methods. Moreover, owing to its usage of a single channel of EEG signal, the proposed method will be suitable for edge-device implementation to expedite sleep disorder diagnosis.

Qualification of Austenitic Stainless Steels for the Development of Load-Sensitive Material Sensors

AbstractTo detect mechanical overloads on the component directly in operation, a metastable material can be used as a load-sensitive sensor when combined with an eddy current testing system. In order to find a suitable metastable sensor material that exhibits microstructural changes at an early stage before fatigue failure, quasi-static tensile tests and cyclic rotating bending tests were carried out with the austenitic stainless steels 1.4301 (2 batches), 1.4305, 1.4541 and 1.4550. For the detection of microstructural changes, electromagnetic testing was used in-situ in the tensile test and ex-situ between the rotating bending test after a pre-defined number of cycles. The investigated materials 1.4301 batch2 and 1.4550 showed the largest signal changes and the lowest austenite stability both in the tensile test and under cyclic bending load. Due to the better mechanical properties, 1.4301 batch2 should be preferred. The order of the austenitic stainless steels tested was similar in terms of transformation behavior in both tests. Thus, the tensile test combined with in-situ electromagnetic testing appears to have potential as a suitable benchmark test for austenite stability. With regard to the cyclic bending stress, an overload of the specimens could be detected for the materials 1.4301 batch2, 1.4305, 1.4541 and for the 1.4550 on the basis of a significant amplitude change. At low bending stresses, uncritical for structural integrity, no increase in amplitude was measured. The results have shown that an early detection of overloads is possible with several materials, however, the potential for detecting overloads varies between materials and also between individual batches. In addition, it has been observed that as the bending stress increases, the gradient of the change in amplitude over the number of cycles increases as well. Thus, with a known number of cycles, it could be possible to classify the previous load spectrum based on the difference in amplitude between two measurements.

Retinal Function in Long-Term Type 1 Diabetes without Retinopathy: Insights from Pattern Electroretinogram and Pattern Visual Evoked Potentials Assessments.

To evaluate changes in pattern electroretinogram (pERG) and pattern visual evoked potentials (pVEP) in patients with long-lasting type 1 diabetes without diabetic retinopathy (DR). Prospective study involving 92 eyes divided into two groups. The diabetic group included 46 eyes of 23 patients with type 1 diabetes (T1DM); the control group included 23 age-matched healthy subjects. pERG and pVEP were assessed using the RETI-port/scan21 recording software (version 1021.3.0.0). Mean age was 48 ± 9.77 years for the diabetic group and 51.7 ± 4.75 years for the control group. The mean duration of diabetes was 28.88 ± 8.04 years. The mean HbA1c value was 7.29 ± 0.89%. There were no differences in the age or sex distribution. Regarding the pERG, T1DM patients exhibited a significant decrease in the amplitude of the P50 and N95 waves compared to the control group (p = 0.018 and p = 0.035, respectively), with no differences in the peak time of each component. pVEP showed no significant changes in either peak time or amplitude of the different components. Long-term T1DM patients without DR showed changes in the amplitude of pERG waves with preserved peak times. We did not observe modifications in pVEP. pERG may serve as a subclinical marker of ganglion cell damage in long-term T1DM patients.

An automatic arrival time picking algorithm of P-wave based on adaptive characteristic function

The accuracy of arrival time and picking speed are significant issues in terms of micro-seismic identification, location, travel-time tomography, as well as source mechanism. In order to detect small changes in signal amplitude and frequency with different signal-to-noise ratios (SNRs), the Allen's characteristic function (Allen's CF) was modified to an adaptive characteristic function (ACF) by relative time series and relative energy coefficients which was compared with the Allen's CF, Baer's CF, and Sedlak's CF. Then, an algorithm for S/L-AIC picker based on ACF for automatic P-wave arrival time picking was presented by the short-term-average to long-term-average ratios (STA/LTA) picker and the Akaike Information Criterion (AIC). In addition, the algorithm was applied to a dataset acquired by a local micro-seismic network at the Jing-Gong coal mine in Shanxi, China, which was compared with a two-step AIC picker, using the original manual selection as a reference to verify the reliability and robustness of the algorithm. Furthermore, the influence of five basic parameters on the accuracy of the S/L-AIC picker based on ACF was discussed by orthogonal tests. The results highlighted that: 81 % of the automatic picks processed by the S/L-AIC picker based on ACF were within +4 ms of deviation, while 66.3 % of the automatic picks processed by the two-step AIC picker were within the same error range; Compared with the other CFs, the ACF applied to the S/L-AIC algorithm performs better for low-SNR data and confirms more accurate and stable results. This study highlights that accurate automatic P-wave arrival time determination is feasible when using the S/L-AIC picker based on ACF.

A multi-feature-based fault diagnosis method based on the weighted timeliness broad learning system

Accurate and timely fault diagnosis is a vital task to ensure process safety of modern industrial facilities. Motivated by the complex variations of process signals and mutual coupling of faults, this paper presents a multi-feature-based fault diagnosis method based on the weighted timeliness Broad Learning System (BLS). The proposed method fuses multiple features extracted from the original process data to improve the fault diagnosis performance, and makes the diagnosis model suitable for dynamic fault diagnosis problems by incorporating the BLS. The major contributions of this study are twofolds: 1) A systematic multi-feature extraction method is proposed to extract long-term trend features, short-term trend features, and binary alarm signals, which reflect the direction and amplitude changes of process signals under faulty conditions; 2) a weighted timeliness BLS structure with multiple fault-sensitive features as the input is proposed to ensure the dynamic characteristics of the fault diagnosis model. The designed fault diagnosis model can be updated in an incremental manner, and thus can improve the model updating efficiency while ensuring accuracy. The effectiveness and superiority of the proposed method is demonstrated by a case study based on the Tennessee Eastman benchmark process.

Fibrin Glue Acutely Blocks Distal Muscle Contraction after Confirmed Polyethylene Glycol Nerve Fusion: An Animal Study.

Polyethylene glycol (PEG) is a synthetic, biodegradable, and hyperosmotic material promising in the treatment of acute peripheral nerve injuries. Our team set out to investigate the impact of fibrin glue upon PEG fusion in a rat model. Eighteen rats underwent sciatic nerve transection and PEG fusion. Electrophysiologic testing was performed to measure nerve function and distal muscle twitch. Fibrin glue was applied and testing repeated. Due to preliminary findings, fibrin glue was applied to an uncut nerve in five rodents and testing was conducted before and after glue application. Mann-Whitney U tests were used to compare median values between outcome measures. A Shapiro-Wilk test was used to determine normality of data for each comparison, significance set at a P value less than 0.05. PEG fusion was confirmed in 13 nerves with no significant change in amplitude (P = 0.054), latency (P = 0.114), or conduction velocity (P = 0.114). Stimulation of nerves following PEG fusion produced distal muscle contraction in 100% of nerves. Following application of fibrin glue, there was a significant reduction in latency (P = 0.023), amplitude (P < 0.001), and conduction velocity (P = 0.023). Stimulation of the nerve after application of fibrin glue did not produce distal muscle twitch. Five uncut nerves with fibrin glue application blocked distal muscle contraction following stimulation. Our data suggest that fibrin glue alters the nerve's function. The immediate confirmation of PEG fusion via distal muscle twitch is blocked with application fibrin glue in this experimental model. Survival and functional outcome studies are necessary to understand if this has implications on the long-term functional outcomes.

In situ monitoring of mechanochemical MOF formation by NMR relaxation time correlation.

In this paper, we present a new approach to monitoring mechanochemical transformations, based on a magnetic resonance (MR) method in which relaxation time correlation maps are used to track the formation of the popular metal-organic framework (MOF) materials Zn-MOF-74 and ZIF-8. The two-dimensional (2D) relaxation correlation measurement employed yields a spectrum which visually and analytically identifies different 1H environments in the sample of interest. The measurement is well-suited to analyzing solid mixtures, and liquids, in complex systems. Application in this work to monitoring MOF formation shows changes in signal amplitudes, and their MR lifetime coordinates, within the 2D plots as the reaction progresses, confirming reaction completion. This new measurement provides a simple way to analyse solid-state reactions without dissolution, and there is a logical pathway to benchtop measurement with a new generation of permanent magnet-based MR instruments. The methodology described permits measurement in an MR compatible milling container, which may be directly transferred from the shaker assembly to the MR magnet for in situ measurement of the entire reaction mixture.

Mechanism and rule of microwave pulse response of two-stage PIN limiter

&lt;sec&gt;This paper aims to analyze the failure mechanism of the two-stage PIN limiter after having been injected by a microwave pulse. A two-stage PIN limiter model with high computational efficiency and accuracy is built by using the method of field-circuit collaborative simulation. Using this model, the temperature change of the PIN diodes during the injection of microwave pulse is simulated. The melting temperature of the PIN diode is selected as the failure criterion of the PIN limiter. The time and energy required for the failure of the PIN limiter under injection of microwave pulses with different frequencies and amplitudes are simulated. Furthermore, the mechanisms that trigger off these effects are analyzed. The relationship between the microwave pulse parameters and the PIN limiter failure time is summarized by using an empirical formula.&lt;/sec&gt;&lt;sec&gt;According to the simulation results, the temperature change of the second-stage PIN diode is relatively small compared with that of the first-stage. During the injection of the microwave pulse, the failure time and energy consumption of limiter show a certain regularity with the variation of microwave pulse amplitude and frequency, and this work discusses this regularity from the following three aspects. Firstly, the failure time and energy consumption decrease in a similar trend with frequency increasing. And with the increase in signal amplitude, the failure time and energy consumption tend to stabilize. Secondly, the increase in the signal amplitude leads failure time to decrease, which is similar to the relationship between failure time and the signal frequency mentioned before. But as the signal’s amplitude increases, the energy consumption first increases and then decreases slightly when the amplitude reaches about 900 V. Based on the theoretical analysis and the physical image of the two-stage PIN limiter, the reasons for these effects can be explained as the changes in the I-region's impedance and heat distribution change caused by electric field changes. Thirdly, the failure time and energy consumption show different sensitivities to different parameters of the microwave pulse. The signal frequency change has greater influence on the energy consumption than the signal amplitude change, while the amplitude change can exert a greater influence on the failure time than the frequency change.&lt;/sec&gt;

Exosomal preconditioning of human iPSC-derived cardiomyocytes beneficially alter cardiac electrophysiology during hypoxia

Abstract Introduction and purpose Cardiac-Exosomes (EXO) are nano-sized extracellular vesicles, continuously secreted by the myocardium. Despite previous misconceptions, cardiac-EXO are not just a way for the cell to dispatch waste, but functions as carriers of signaling molecules. Furthermore, the effects of cardiac-EXO signaling during hypoxic stress is not well understood. The present study aimed to determine the biological effects of EXO released from hypoxic cardiomyocytes, focusing on whether the EXO-cargo can benefit recipient cells during hypoxic stress. We hypothesize that cardiomyocytes exposed to hypoxic stress would display advantageous electrophysiological properties after preconditional treatment with isolated cardiac-EXO secreted from cardiomyocytes exposed to hypoxic stress. Methods For preconditional treatment we isolated EXO from human iPSC-derived cardiomyocytes (CM) exposed to hypoxia (1% O2) for 16 h (H-EXO). H-EXO was thereafter administrated as preconditional treatment to a secondary population of CM 24 h before subjection to 16 h of hypoxia. Electrophysiological effects of H-EXO precondition treatment were assessed with a multiwell microelectrode array (MEA) system. Using the MEA-system; field potential, beat period, spike slope, spike amplitude, excitation-contraction (EC) coupling, and cardiac action potentials were recorded and analyzed. Results We found that CM exposed to hypoxic stress conditions (16 hours) displayed significant increase in beat period when preconditioned with H-EXO compared to non-treated CM (+15.7%, p&amp;lt;0.05). Furthermore, precondition with H-EXO resulted in faster EC coupling compared with non-treated CM after 16 h of hypoxia (-25.3%, p&amp;lt;0.05). More efficient EC coupling indicates that the H-EXO recipient cells are less affected by the hypoxic stress. There were no significant changes in field potential, spike slope, spike amplitude and cardiac action potential between the two groups after 16 h of hypoxia. Conclusion The present study report that EXO secreted by CM under hypoxia alter electrophysiological properties in recipient cells exposed to 16 h hypoxic stress. The alterations indicate more efficient cardiomyocyte EC coupling and longer beat period.

Otoprotective Effects of Quercetin Against Oxidative Damage in the Rat's Cochlea Induced by Noise and Silver Nanoparticles.

The aim of this study was to investigate the otoprotective effects of Quercetin (Que) against both noise-induced hearing loss (NIHL) and the ototoxicity of silver nanoparticles (SNPs) in rats. Forty-two male Wistar rats were divided into seven groups (n=6): control, SNPs, Que (100mg/kg) plus SNPs (100mg/kg), noise (104dB), Que plus noise, noise plus SNPs, and noise plus Que plus SNPs. In the weight change results, there was no significant difference between the groups exposed to noise plus SNPs and SNPs compared to the control group. However, animals had significant changes in DPOAE amplitude at 1 and 3days post-exposure when compared to baseline. Additionally, the DPOAE value of rats administered with Que plus SNPs was higher than in all other groups. Que also decreased the levels of TACT, MDA, IL-6, TNF-α, and NOX3 in the groups exposed to noise and SNPs and increased the SOD level and expression of myosin heavy chain VII (MYH7) and β-tubulin III (TUBB3) proteins. Furthermore, Que decreased structural changes in the animals' cochlea. Our findings indicate that pretreatment with Que efficiently counteracted the adverse effects of noise and SNPs on inner hair cell, outer hair cell, and nerve cells, which are responsible for high-frequency perception.

Repetitive sensorimotor mu-alpha phase-targeted afferent stimulation produces no phase-dependent plasticity related changes in somatosensory evoked potentials or sensory thresholds.

Phase-dependent plasticity has been proposed as a neurobiological mechanism by which oscillatory phase-amplitude cross-frequency coupling mediates memory process in the brain. Mimicking this mechanism, real-time EEG oscillatory phase-triggered transcranial magnetic stimulation (TMS) has successfully induced LTP-like changes in corticospinal excitability in the human motor cortex. Here we asked whether EEG phase-triggered afferent stimulation alone, if repetitively applied to the peaks, troughs, or random phases of the sensorimotor mu-alpha rhythm, would be sufficient to modulate the strength of thalamocortical synapses as assessed by changes in somatosensory evoked potential (SEP) N20 and P25 amplitudes and sensory thresholds (ST). Specifically, we applied 100 Hz triplets of peripheral electrical stimulation (PES) to the thumb, middle, and little finger of the right hand in pseudorandomized trials, with the afferent input from each finger repetitively and consistently arriving either during the cortical mu-alpha trough or peak or at random phases. No significant changes in SEP amplitudes or ST were observed across the phase-dependent PES intervention. We discuss potential limitations of the study and argue that suboptimal stimulation parameter choices rather than a general lack of phase-dependent plasticity in thalamocortical synapses are responsible for this null finding. Future studies should further explore the possibility of phase-dependent sensory stimulation.

Mirror neuron activity depending on the content and stage of the observed action: a TMS study.

The firing rate of the mirror neuron system in monkeys decreases systematically with more repetitions. The aim of this study is to investigate whether the activity of the mirror neuron system varies based on the observed movement and the contents of the action, as well as whether there is inhibition in the mirror neuron system when humans observe repeated actions. If inhibition is present, the second question of the study is whether it is related to the organization of the observed action. Fourteen healthy volunteers participated in the study. Transcranial magnetic stimulation was applied to the left primary motor cortex and motor evoked potentials (MEPs) were recorded from the right first dorsal interosseous and abductor pollicis brevis muscles while the participants were watching videos specially prepared for the study. There were no significant changes in MEP amplitudes compared to baseline MEPs while observing aimless action. However, while participants watched the repeated action video, the mean MEP amplitude increased at the beginning of the movement, but neither facilitation nor inhibition was detected when the participants watched the phase of grasping the object of the action compared to the baseline MEP amplitude. On the other hand, while participants were watching different activities, an increased MEP amplitude was observed at the beginning of the movement and in the grasping of the object of the action. Additionally, there was no significant reduction in MEP amplitude during any movement stages while observing the repeated action video. The findings of this study suggest that the activation of the mirror neuron system in humans depends on the content and stages of the observed movement. Additionally, there was no inhibition or systematic reduction in MEP amplitudes while watching a repeated action.