Signal Amplitude Research Articles

Power System Signal-Detection Method Based on the Accelerated Unsaturated Stochastic Resonance Principle

The classical bistable stochastic resonance algorithm has an inherent output saturation defect that restricts the amplitude of the output signal. This paper examines the causes of this phenomenon and its negative impact on the detection of weak signals. Proposing the Unsaturated Bistable Stochastic Resonance (UBSR) detection algorithm involves constructing a segmented potential function using a linear function to eliminate the effect of higher-order terms in the classical stochastic resonance algorithm. A new type of segmented potential function has been created by combining exponential and linear functions. This new function helps to eliminate the impact of higher-order terms in classical algorithms while also improving the noise immunity of the stochastic resonance system. This results in the development of the accelerated stochastic resonance (ASR) detection algorithm. In this paper, the Kramers escape rate and output signal-to-noise ratio of two improved stochastic resonance algorithms are theoretically derived and compared with the classical bistable stochastic resonance algorithms, and the proposed algorithms are able to effectively avoid the output saturation phenomenon and have more excellent detection performance under strong background noise.

P20 Characterizing monoamine signalling in human dermal fibroblasts and keratinocytes

Abstract Introduction and aims Our mental health depends upon a fine balance of monoamines in the brain. Interestingly, there is ample evidence indicating that mental health disorders such as stress or anxiety have an impact on skin condition and appearance. For example, stress induces neurogenic inflammation, which in turn leads to mast cell degranulation in the skin and increases local histamine levels. This increased histamine within the skin exacerbates skin conditions such as eczema and psoriasis, while impacting the skin barrier. In this study, we first sought to investigate monoamine signalling in both skin keratinocytes and fibroblasts, with a specific focus on histamine and serotonin modulation. Next, we investigated mechanisms of release via pharmacological intervention to block corresponding receptors, informed by using single-cell RNA sequencing from existing datasets. Methods We adapted a powerful electrochemical technique, fast-scan cyclic voltammetry (FSCV) to codetect monoamine signalling in real-time in vitro. Employing the advanced capabilities of our artificial neural network models, we analysed extensive FSCV colour plot data in real-time to establish neurotransmitter release patterns and understand their characteristics. Results Our Results show that both keratinocytes and fibroblasts are capable of releasing serotonin and histamine without external intervention. After administering diphenhydramine, an H1 receptor inhibitor, to the cells, we observed a rise in the frequency and amplitude of both serotonin and histamine signalling compared with the cells that received no treatment. However, bafilomycin, a vacuolar H+ ATPase inhibitor, reduced the signalling frequency significantly. This suggests a potential autoregulation mechanism and interdependency between the two monoamines. Conclusions Overall, using analytical Methods, our work shows that skin-resident fibroblasts and keratinocytes can release monoamines including serotonin and histamine. This finding provides an opportunity to examine interventions that facilitate serotonin release, to decrease histamine levels, and improve the skin function and general mental wellbeing.

Characterization of cracking-healing cycle of asphalt mixture based on air-coupled second harmonic measurement using Duffing-van der pol oscillator

Second harmonic generation (SHG) technique using Rayleigh surface wave has been successfully attempted for the non-destruction evaluation of asphalt mixture during the self-healing process. The air-coupled transducer placement is desirable for the convenient implementation of SHG for the large-scale detection. Nevertheless, the pronounced attenuation of ultrasonic wave by air-coupled propagation will cause the second harmonic induced by microcracks to be barely detectable, particularly under the influence of inevitable noise. In this study, a novel approach by combining Duffing oscillator and van der pol equation is developed to identify and quantify the second harmonic in noise-contained signals based on the phase trajectory and periodic trajectory area exponent. The multi-physics finite element model is first established to simulate the air-asphalt propagation of Rayleigh waves, and proof-of-concept numerical simulations are carried out to estimate the second harmonic amplitude of noise-contaminated signals. The air-coupled SHG experiments are conducted, and the approach of the Duffing-van der pol oscillator is applied to extract the second harmonic in experimental data, and the self-healing behavior of asphalt mixture is analyzed through the variation of the nonlinear parameter of SHG measurements. The results indicate that the contactless SHG method combined with the Duffing-van der pol oscillator can effectively realize the convenient and reliable estimation of the nonlinear ultrasonic signal during the cycle of asphalt deterioration and healing, which is important for the property characterization of asphalt mixture considering its high attenuation to the ultrasonic waves.

REPOLARIZATION GRADIENT CAUSES LOCAL DEPOLARIZATION ABNORMALITIES IN BRUGADA SYNDROME

Abstract Background Transmural voltage gradient in RVOT induces ECG–phenotype in Brugada syndrome(BrS). Moreover,RVOT depolarization abnormalities have been described as contributors to BrS phenotype and arrhythmogenesis. Purpose To investigate the effect of ajmaline administration on J–elevation of RVOT unipolar signals in BrS patients. Moreover,we wanted to assess whether ajmaline–induced unipolar J–point elevation variations induced local depolarization abnormalities. Methods 21 BrS patients with spontaneous type–1 ECG pattern were enrolled. Due to the absence of BrS ECG pattern at the study, patients underwent RV endocardial mapping with the CARTO3 system, before (PRE) and after (POST) ajmaline administration. The data were exported from CARTO and converted into Matlab format using OpenEP. J–elevation for each point was calculated as the amplitude of the unipolar signal at J wave with respect to baseline. Activation time (AT) of each point was defined as the difference between local depolarization (minimum dV/dt of the unipolar signal) and surface ECG depolarization(time of the minimum signal on V2). With an automatic algorithm, corresponding PRE and POST points were selected. The difference between POST and PRE of each parameter was calculated to obtain the differential values delta–J and delta–AT. Differential values were then interpolated on the mesh of each subject to obtain 3D maps. The deltaJ map was divided into four intervals based on quartiles. We then selected a ROI ‘IN‘ on a region with the greatest deltaJ variation, and a second ROI ‘OUT‘ on the zone of lowest variation. The same ROIs were applied to the deltaAT map. The mean value of the respective differential parameters was extracted in each ROI. Results Greatest delta–J values were found in the RVOT/anterior wall. delta–J in the ROI ‘IN‘ was greater than in the ROI ‘OUT‘ (1.68 [1.11–2.28] vs 0.56 [0.38–0.93] mV, p<0.001). delta–AT in the ROI ‘IN’ was greater than in the ROI ‘OUT’ (27.96 [20.39–44.89] vs 7.62 [4.24–16.69] ms, p<0.001). A good correlation was found between delta–J and delta–AT, considering the data for the two ROIs together (Spearman R coefficient=0.71, p<0.001). Conclusions: Our study shows that the repolarization gradient, evaluated by localized delta–J increase in RVOT, justifies BrS ECG phenotype and local depolarization abnormalities. A strong correlation was present in these RVOT areas between J–elevation variation and slow conducting zones.

Correlations between the optical phase modulation and the optical frequency and phase shifts in ultrasound-modulated optical tomography

In ultrasound-modulated optical tomography, ultrasound causes the phase of incident light to vary periodically with ultrasound. The periodic variation in phase is known as phase modulation. The phase modulation causes the modulated light intensity to vary periodically with the ultrasound, which is called ultrasonic modulation of light. As is well known, incident light is shifted in frequency and phase by ultrasound in acousto-optic effect, and the tomography is based on the effect. However, the correlations between the phase modulation and the frequency and phase shifts in the ultrasonic modulation of light have been ignored. In this paper, the correlations are investigated theoretically and experimentally in detail. Studies reveal that the modulated light is phase-modulated by the frequency and phase shifts, and the frequency shift is the fundamental cause for the ultrasonic modulation of light. Studies show that the frequency shift, rather than the phase shift, causes the modulated light intensity to vary periodically with the ultrasound. Additionally, the modulated light intensity signal is composed of cosine signals with frequencies Ω, 2Ω, 3Ω, etc, and the amplitude of the cosine signals depends on the amplitude of the phase modulation. Then, the modulated light intensity signal contains relatively more cosine signals with high frequency as the amplitude of the phase modulation increases. At last, for the ultrasound with lower power, the amplitude ratio of cosine signals with frequencies of 2Ω and Ω increases as the scattering coefficient of turbid media increases. Studies find that both the frequency-shifted light and the amplitude ratio can be used to image turbid media.

RFDrive: Tagged Human-Vehicle Interaction for All

Human–vehicle interaction is an important factor for safe driving. The driver needs to interact with the in-vehicle steering wheel and infotainment system properly during driving. Specifically, driving guidelines require the driver to hold the steering wheel at the 3 o’clock and 9 o’clock positions. Moreover, the in-vehicle infotainment system should be more adaptive for the driver and front-seat passenger during driving (i.e., the in-vehicle infotainment system should be part and even fully disabled for the driver, whereas the front-seat passenger should be able to enjoy the full in-vehicle infotainment system). However, affordable vehicles are usually designed to achieve basic driving functions without considering safe human–vehicle interactions, which require an add-on, affordable, and ready-to-use human–vehicle interaction monitoring system. In this article, we present RFDrive, a system that can simultaneously locate the driver’s hand positions on the steering wheel and automate in-vehicle infotainment system touch discrimination for safe driving using commodity passive RFID tags. Since these commodity passive RFID tags are low cost (i.e., around 5 cents per tag), battery free, and are small, like a sticker, our design will enable not only safe driving but is also low cost, which can lead to sustainable solutions. To do so, we attach RFID tags on the steering wheel for the driver’s hand position location and attach RFID tags on the roof of the vehicle’s interior for in-vehicle infotainment system touch discrimination (i.e., differentiating the driver’s infotainment system touch and front-seat passenger’s infotainment system touch). However, the wheel steering will distort the wireless channel-based driver’s hand position location on the steering wheel. Thus, we propose a novel tag ID-based algorithm to locate the driver’s hand position on the steering wheel by harnessing the human body as part of the RFID tag’s antenna. Since the in-vehicle infotainment system touch from the driver or front-seat passenger will affect different RFID tags attached to the roof of the vehicle’s interior, we propose to use the differential amplitude of backscattered signals from all the tags to discriminate in-vehicle infotainment system touch sources. Our experiments show that RFDrive can achieve the average accuracy of 0.98 and 0.98 for in-vehicle touch source discrimination and driver’s hand position location, respectively.

A Novel Low-Frequency Electromagnetic Active Inertial Sensor for Drug Detection.

The purpose of this paper is to demonstrate a new discovery regarding the interaction between materials and very low radio frequencies. Specifically, we observed a feedback response on an inertia active sensor when specific frequencies (around 2-4 kHz) are used to irradiate targeted pharmaceutical samples like aspirin or paracetamol drugs. The characteristics of this phenomenon, such as excitation and relaxation time, the relation between deceleration and a material's quantity, and signal amplitude, are presented and analyzed. Although the underlying physics of this phenomenon is not yet known, we have shown that it has potential applications in remote identification of compounds, detection, and location sensing, as well as identifying substances that exist in plants without the need for any processing. This method is fast, accurate, low-cost, non-destructive, and non-invasive, making it a valuable area for further research that could yield spectacular results in the future.

Review and comparison of linear algorithms to quantify muscle fatigue based on sEMG signals

Surface electromyography techniques are widely used in field of motion analysis and ergonomics combining precise muscular activation assessment with low-invasiveness and wearability. The aim of this investigation is to identify the myoelectrical manifestations of fatigue and to compare the effectiveness of sEMG-based quantitative indices for fatigue assessment. The investigated indexes are the ARV and RMS signal amplitudes, the mean frequency, the median frequency, the Dimitrov index, the instantaneous mean frequency and Wavelet distribution-based WIRE51 index. Two different protocols were developed, and the activity of the lateral deltoid and middle trapezius muscles was recorded. The WIRE51 index is found to have the highest sensitivity in the detection of the difference between the repetitions of each exercise for both protocols. Due to the lack of a unified standard for the performance comparison of fatigue indices, a correlation analysis was carried out between the result provided by the indices and the subjective fatigue perception employing the RPE scale.

The research on triple-coil inductive debris sensor with electromagnetic shielding

A high sensitivity inductive debris sensor is of great significance for oil condition monitoring and the fault diagnosis of mechanical equipment. However, inductive sensors are susceptible to interference from external electromagnetic fields. In this study, an inductive debris sensor with a shielding layer is studied, which can effectively reduce the influence of external magnetic fields on the sensor. Theoretical and experimental results verify the effectiveness of the shielding layer, and also show that the shielding layer impacts the magnetic field of the sensor, resulting in a decrease in the amplitude of the output signal. Detailed analysis was conducted to investigate the effect of structural parameters on the performance of inductive sensors. These parameters include the distance between the shielding layer and the coils, the thickness of the shielding layer, and the shielding layer material. Based on the theoretical and experimental results, reference suggestions are provided for the design of the shielding layer. This study ensures the performance and reliability of inductive sensors in practical applications.

Asymmetric drift in MaNGA: mass and radially dependent stratification rates in galaxy discs

ABSTRACT We measure the age–velocity relationship from the lag between ionized gas and stellar tangential speeds in ∼500 nearby disc galaxies from MaNGA in Sloan Digital Sky Survey IV (SDSS-IV). Selected galaxies are kinematically axisymmetric. Velocity lags are asymmetric drift, seen in the Milky Way’s (MW) solar neighbourhood and other Local Group galaxies; their amplitude correlates with stellar population age. The trend is qualitatively consistent in rate ($\dot{\sigma }$) with a simple power-law model where σ ∝ tb that explains the dynamical phase-space stratification in the solar neighbourhood. The model is generalized based on disc dynamical times to other radii and other galaxies. We find in-plane radial stratification parameters σ0,r (dispersion of the youngest populations) in the range of 10–40 km s−1 and 0.2 < br < 0.5 for MaNGA galaxies. Overall, brincreases with galaxy mass, decreases with radius for galaxies above 10.4 dex (M⊙) in stellar mass, but is ∼constant with radius at lower mass. The measurement scatter indicates the stratification model is too simple to capture the complexity seen in the data, unsurprising given the many possible astrophysical processes that may lead to stellar population dynamical stratification. None the less, the data show dynamical stratification is broadly present in the galaxy population, with systematic trends in mass and density. The amplitude of the asymmetric drift signal is larger for the MaNGA sample than the MW, and better represented in the mean by what is observed in the discs of M31 and M33. Either typical discs have higher surface-density or, more likely, are dynamically hotter (hence thicker) than the MW.

Earthquake source impacts on the generation and propagation of seismic infrasound to the upper atmosphere

SUMMARY Earthquakes with moment magnitude (Mw) ranging from 6.5 to 7.0 have been observed to generate sufficiently strong acoustic waves (AWs) in the upper atmosphere. These AWs are detectable in Global Navigation Satellite System satellite signals-based total electron content (TEC) observations in the ionosphere at altitudes ∼250–300 km. However, the specific earthquake source parameters that influence the detectability and characteristics of AWs are not comprehensively understood. Here, we extend our approach of coupled earthquake-atmosphere dynamics modelling by combing dynamic rupture and seismic wave propagation simulations with 2-D and 3-D atmospheric numerical models, to investigate how the characteristics of earthquakes impact the generation and propagation of AWs. We developed a set of idealized dynamic rupture models varying faulting types and fault sizes, hypocentral depths and stress drops. We focus on earthquakes of Mw 6.0–6.5, which are considered the smallest detectable with TEC, and find that the resulting AWs undergo non-linear evolution and form acoustic shock N waves reaching thermosphere at ∼90–140 km. The results reveal that the magnitude of the earthquakes is not the sole or primary factor determining the amplitudes of AWs in the upper atmosphere. Instead, various earthquake source characteristics, including the direction of rupture propagation, the polarity of seismic wave imprints on the surface, earthquake mechanism, stress drop and radiated energy, significantly influence the amplitudes and periods of AWs. The simulation results are also compared with observed TEC fluctuations from AWs generated by the 2023 Mw 6.2 Suzu (Japan) earthquake, finding preliminary agreement in terms of model-predicted signal periods and amplitudes. Understanding these nuanced relationships between earthquake source parameters and AW characteristics is essential for refining our ability to detect and interpret AW signals in the ionosphere.

Dynamic thresholding logarithmic companding for PAPR reduction in MIMO-OFDM systems for 5G wireless communication

In order to advance 5G wireless communication technology, this paper presents a novel method for lowering the Peak-to-Average Power Ratio (PAPR) in Multiple-Input Multiple-Output Orthogonal Frequency-Division Multiplexing (MIMO-OFDM) systems. It is called the Dynamic Thresholding-based μ-law (DT-μ-law) logarithmic companding technique, and it greatly improves the performance of the system by effectively broadcasting data streams on a single frequency across multiple channels. This technique's ability lies in compressing the amplitude of the transmitting signal beyond a specific threshold value before the parallel-to-serial conversion block in the MIMO-OFDM system. It employs the direct insertion of an offset value into the guard bits, rather than using a step function for the amplitude reduction process, which can reduce additional system complexity and data loss during signal expansion at the receiver end. This technique is more adequately suited for dynamic data rate shifting and interference within a limited threshold value. The dynamic thresholding value (α) is determined by calculating the median and standard deviation of the μ-law companding. This ensures the effective compression of higher amplitude signals at the transmitter, using μ-law log companding. To streamline the decompanding process at the receiver, an offset is introduced, facilitating a smoother transition and reducing complexity. The results demonstrate that the proposed DT- μ-law companding technique significantly improves PAPR reduction while maintaining low Bit Error Rates (BER) and high average spectral power efficiency. This efficiency is optimal when the μ value is maintained within the range of 4–4.5. Furthermore, it was observed that an increase in the μ value corresponds to a decrease in both PAPR value and BER. Specifically, at a signal-to-noise ratio of 15.2 dB, the BER stabilizes at 10−1. Compared to existing methods like the Max-Min Decomp-SLM approach, this technique offers lower Signal-to-Noise Ratio (SNR) values, thereby enhancing spectral efficiency and maximizing data capacity.

Method for the P-wave arrival pickup of rock fracture acoustic emission signals under strong noise

This research aimed to investigate the accuracy of picking of P-wave arrival times in rock fracture acoustic emission signals. In order to simulate the mining scenario, Gaussian white noise and pulse noise were added to the data collected in the laboratory. Complete ensemble empirical mode decomposition with adaptive noise + Wavelet (CEEMDAN + Wavelet) was improved in this paper, where the Spearman rank correlation coefficient was adopted to effectively select intrinsic mode functions for denoising which retained the inherent characteristics of the rock fracture signal. The absolute amplitude and energy change rate of the envelope signal, calculated based on the Hilbert transform, were used as the input of the short term average/long term average (STA/LTA) normalization algorithm to pickup the P-wave arrival time. The reliability of this method was tested on 30 groups of recorded rock fracture laboratory data and 60 groups of added noise data. Taking the manual pickup results as the standard, the errors of CEEMDAN + Wavelet + STA/LTA + AIC (Akaike information criterion) method with the absolute amplitude of the signal as the input are all within 10 ms, and 86.67% of the results are within 5 ms. The method proposed in this paper effectively addressing the issue of false pickup caused by the sensitivity of AIC and traditional STA/LTA method for strong noise, and achieving relatively high accuracy and stability in processing low signal-to-noise ratio signals. This work contributes to monitor microscopic changes in rock bodies and is of great significance for the prediction and monitoring of geological disasters.

Study on fault characteristic of piezoelectric acceleration sensor

In order to explore the fault characteristics and failure mechanism of the sensor, staring from the working principle and structural characteristics of the piezoelectric acceleration sensor, the problems affecting the quality of the collected signal due to the fault of the component of the sensor are systematically studied. Firstly, according to the application scenario and structural characteristics of this kind of sensor, the main fault forms are analyzed, including: insufficient preload, crystal plate damage, crystal plate side loading and crystal plate phase loading reverse four kinds of faults. Secondly, the signal of the exciter is used to test the above sensors. It is found that except the sensor with insufficient preload does not affect the signal, other fault sensors will make the collected signal amplitude smaller, but the signal frequency does not change. In order to verify the accuracy of the exciter test results, the sensor signal test on rotor bearing vibration was continued. The test results show that not only the signal amplitude decreases, but also the high frequency part of the signal is seriously distorted. Finally, the fault characteristics of various components of piezoelectric acceleration sensor are obtained by combining the test results of the two groups.

Characterizing Liquid Water in Deep Martian Aquifers: A Seismo‐Electric Approach

AbstractDeep Martian aquifers harboring liquid water could hold vital insights for current and past habitability. We show that with seismo‐electric interface responses (IRs) we can quantitatively characterize subsurface water on Mars. Full‐waveform simulations and sensitivity analyses across diverse Martian aquifer scenarios demonstrate the technique's effectiveness. In contrast to how seismo‐electric signals often appear on Earth, Mars' desiccated surface naturally removes co‐seismic fields and exposes useful IRs that allow us to characterize several aquifer properties. Changing the aquifer depth, thickness, or quantity changes the IR arrival times or shape: aquifer depth is a strong control on evanescent IRs, thickness affects the relative timing of IRs, and increasing the number of aquifers introduces more dipole sources to the waveform. Other factors, such as aquifer saturation, chemistry, and salinity, strongly affect IR amplitude but have minimal or no effect on waveform shape. Notably, for a deep low‐porosity aquifer, the salinity and brine chemistry (perchlorate vs. chloride) are the strongest controls on signal amplitude. Analyzing the effects of epicentral distance shows that radiating and evanescent IRs separate at large source‐receiver offset, allowing analyses of both signals and accurate event distance derivation. From this numerical investigation of the sensitivity of IRs to deep Martian aquifers, we anticipate future analyses of electromagnetic data from the InSight lander or future missions to Mars and other planets.

A high-performance surface acoustic wave sensing technique.

We present a superheterodyne-scheme demodulation system that can detect the amplitude and phase shift of weak radio frequency signals with extraordinarily high stability and resolution. As a demonstration, we introduce a process to measure the velocity of the surface acoustic wave using a delay-line device from 30K to room temperature, which can resolve <0.1 ppm velocity shift. Furthermore, we investigate the possibility of using this surface acoustic wave device as a calibration-free, high sensitivity, and fast response thermometer.

How robust are gravitational wave predictions from cosmological phase transitions?

Abstract Gravitational wave (GW) predictions of cosmological phase transitions are almost invariably evaluated at either the nucleation or percolation temperature. We investigate the effect of the transition temperature choice on GW predictions, for phase transitions with weak, intermediate and strong supercooling. We find that the peak amplitude of the GW signal varies by a factor of a few for weakly supercooled phase transitions, and by an order of magnitude for strongly supercooled phase transitions. The variation in amplitude for even weakly supercooled phase transitions can be several orders of magnitude if one uses the mean bubble separation, while the variation is milder if one uses the mean bubble radius instead. We also investigate the impact of various approximations used in GW predictions. Many of these approximations introduce at least a 10% error in the GW signal, with others introducing an error of over an order of magnitude.

An Accurate Modeling Method of Body-thread of Penetration Fuze in FEM

To address the issue that the influence of body-thread on the acceleration signal characteristics in penetration fuze is ambiguous, an accurate modeling method of body-thread is proposed in the finite element method (FEM). The body-thread element segments are obtained by the three-dimensional entity thread model, the initial layer nodes set and elements on the outer surface of the thread are established, and the initial layer elements are copied, rotated, and translated. Repeat this transformation, and get a complete thread model. This method is applied to simulation analysis of a warhead penetrating 4-layer concrete plates, and the influence of thread connection on acceleration signal characteristics in penetration fuze is studied. By comparing the acceleration signal and frequency spectrum of the proposed thread model with that of the simplified thread model, the amplitude of the acceleration signal of the proposed one is smaller than that of the simplified one in some certain frequency spectrum. It shows that the thread connection structure has with damping effect and effectively reduces the high-frequency interference of acceleration signal in penetration fuze.

Resonance Detection Method of AC-DC Hybrid Micro-grid Based on Wavelet Transform and Fast Fourier Transform

The grid connection of a mass of distributed power sources in the AC/DC hybrid micro-grid will cause harmonics, voltage sags, voltage fluctuations, and flicker in the grid, which seriously affects the power quality of the grid. Therefore, the power quality problems such as the resonance generated by the AC/DC hybrid micro-grid need to be studied urgently. In this paper, a resonance detection technology based on the combination of wavelet transform (WT) and fast Fourier transform (FFT) is proposed. This method uses wavelet transform to process the high-frequency and low-frequency parts of the signal separately, and eliminates part of the interference signal. The method then uses the FFT to obtain the resonance content. The AC/DC hybrid micro-grid resonance detection method based on WT and FFT can not only determine the time and amplitude of the resonance signal, but also filter the interference signal and improve the accuracy of frequency domain analysis. It is verified by simulation that the algorithm can detect the resonance of the AC/DC hybrid micro-grid.

Contribution Of TRPV4 Channels To Calcium Signaling Profiles Of The Lung Microvascular Endothelium Under Acidic pH

Maintenance of lung endothelial barrier integrity is achieved to a great extent through effcient homeostatic endothelial calcium signaling in the lung microvasculature. The transient receptor potential vanilloid 4 (TRPV4), a non-selective calcium permeable channel has been implicated in several pulmonary pathologies involving lung barrier disruption. These channels are activated by various physical forces and chemical stimuli, but their underlying contribution to inherent and distinct microvascular endothelial Ca2+ signaling profiles are unknown. We previously assessed the role of TRPV4 channels in basal Ca2+ signaling dynamics of the pulmonary microcirculation under differing conditions of stretch and temperature. In the current study, we evaluate the impact of acidic pH (7.1, resembling acidosis) on the distinct endothelial Ca2+ signaling events in the mouse lung microcirculation and examine the participation of TRPV4 channels. Lung slices isolated from the Cdh5-GCaMP8 mice (transgenic mice with Ca2+-dependent fluorescent indicator expressed specifically within vascular endothelial cells) were mounted on Sylgard inserts with HEPES buffer (pH 7.45) and imaged for their basal signaling events using spinning disk confocal microscopy. After an initial baseline recording, the bathing solution was replaced with acidic HEPES buffer (pH 7.1) and recordings were made for approximately two minutes at 5 frames per second. These slices were then treated with the TRPV4 channel inhibitor GSK2193874 (3μM) or vehicle. The recorded image sequences were analyzed by using ImageJ and our custom signal tracking software S8, for quantification of the Ca2+ signaling profiles through event frequency, amplitude, duration and spread. Subjecting the lung slices to pH 7.1 increased the amplitude and spatial spread of the signaling events but the duration and frequency of the events remained relatively constant when compared to baseline recorded events. Addition of the channel blocker diminished the signaling event frequency, amplitude and spatial spread of the lung tissues. The normal pH and vehicle control for the above experiments did not show any relative change from the baseline signaling event profiles. To summarize, treating the lung slices to acidic pH increased the event amplitude and event spatial area distributions, indicating widespread activation of Ca2+ entry events. These increased event parameters were reduced upon addition of the antagonist, suggesting higher contribution of TRPV4 channel induced Ca2+ signaling events under acidic pH. We conclude that the channels contribute minimally to basal dynamics under homeostatic conditions but are activated to a greater extent under stimulations resembling pathological conditions like acidosis or acid aspirations. NIH P01 HL066299, R01 HL155288, NIH S10 0D020149. 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.