Pulse Interval Research Articles

The acute effect of bitemporal electroconvulsive therapy on synchronous changes in heart rate variability and heart rate in patients with depression.


The transient autonomic nervous system responses induced by electroconvulsive therapy (ECT) may serve as critical indicators of treatment efficacy and potential side effects; however, their precise characteristics remains unclear. Considering that the intense stimulation of ECT may disrupt the typical antagonistic relationship between the sympathetic and parasympathetic branches, this study aims to conduct a meticulous analysis of the rapid changes in heart rate variability and heart rate during ECT, with a particular focus on their synchronized interplay.
Methods:
Pulse interval sequences were collected from fifty sessions of bitemporal ECT administered to twenty-seven patients diagnosed with major depressive disorder. The average heart rate (HR) and ultra-short term (UST) heart rate variability (HRV) indices RMSSD and SDNN, as well as the Poincaré indices SD1, SD2 and SD2/SD1, were calculated using a 10-second sliding window with a step size of 1 second. In particular, the synchronous changes between SD1, SD2, SD2/SD1 and HR were analyzed.
Results:
The synchronous changes of the indices showed different characteristics over time. In particular, SD1, SD2 and HR increased significantly by 41.50±11.45 ms, 33.97±10.98 ms and 9.68±2.00 bpm respectively between 8 and 20 seconds, whereas they decreased significantly by 19.89±9.07 ms, 17.54±8.54 ms and 3.80±1.33 bpm respectively between 45 and 53 seconds after ECT stimulus onset. SD1, SD2 and SD2/SD1 all had highly significant positive correlations with HR in the above phases.
Conclusion:
 The results suggest that bitemporal ECT induces the sympathetic and parasympathetic co-activation during the early ictal period and brief co-inhibition approximately 45 seconds after stimulus. Our findings may provide new insights comprehending the mechanisms of ECT and its associated cardiovascular risks.&#xD.

Molecular Dynamics Study of Protein-Mediated Electroporation of Kv Channels Induced by nsPEFs: Advantages of Bipolar Pulses.

Nanosecond pulsed electric fields (nsPEFs) can induce protein-mediated electroporation (PMEP) in voltage-gated ion channels. However, their effects on the tetrameric structure of voltage-gated potassium (Kv) channels remain unexplored. Our study pioneered the molecular dynamics (MD) investigation of the open-state (O) Kv channel to understand the effects of PMEP under unipolar and bipolar pulses (UP and BP). Our findings revealed that BP induces pore formation more effectively than UP. Additionally, the frequency of pore formation shows a more consistent decline with increased pulse interval under BP. We further examined three other distinct functional states─intermediate (C*), inactivated (I), and resting closed (C)─of Kv channels under BP. SF pores formed exclusively in the O state, while complex pores formed only in the O and C states. In conclusion, our study highlights BP's role in enhancing pore formation and specificity, offering insights into Kv channel PMEP and its therapeutic potential.

Design dimensions of electrocutaneous warning stimulation patterns in workplace safety devices.

Warning of workers in dangerous situations is crucial. With the aim of deriving practical parameters for an electrocutaneous warning stimulation, we explore the design dimensions of pulse intervals, amplitudes, and locations of electrocutaneous stimulation in a study on healthy volunteers. Using biphasic rectangular current pulses on the upper right arm of 81 healthy participants, they evaluated temporal perception with varying intervals, ranging from 200 ms down to 0.5 ms, categorizing it as 'Individual pulses', 'Pulsating', 'Vibrating', or 'Continuous'. Next, we tested nine amplitude levels. Participants rated the perceived amplitude on a scale from 1 to 9 after a training phase. Finally, we presented five consecutive stimulation pulses in a pseudo-random order at eight electrode pair positions, asking participants to report the stimulated electrode pair. Participants perceived electrocutaneous pulses as 'Individual pulses' for median intervals above 74 ms, as 'Pulsating' between 44 ms and 74 ms, as 'Vibrating' between 12 ms and 44 ms, and as 'Continuous' below 12 ms. Pulse intervals below about 1 ms were perceived as weak and at about 5 ms as inconvenient, rendering these intervals less suitable for the design of a warning pattern. The median reported amplitudes [25%-75%-percentile] for presented amplitudes 1 to 9 are: 1[1-1], 2[2-3], 3[2-4], 3[3-4], 4[3-5], 5[4-6], 6[4-7], 7[5-8] and 7.5 [6-8] indicating a linear relationship between presented and perceived amplitude. These results suggest that the stimulation amplitude may be incorporated into a structured stimulation pattern. The majority of the electrode pair locations were reported correctly (64.3%-86.6%) or within the two neighboring electrode pairs (98%-99.7%). We conclude that the determined pulse intervals combined with the differentiability of locations offer the basis for designing a warning signal. Our research lays the groundwork for developing suitable signals for wearable electric warning devices.

INVESTIGATION OF THE NEUTRINO CHANNEL AT THE U-70 ACCELERATOR COMPLEX WITH PARENT PARTICLE BEAM DEFLECTION

Principle optical scheme of the neutrino beam production channel based on the accelerator complex U-70 is considered. In order to extract the required pulse interval of π-mesons, a two-magnetic system with a “field” lens with a one-way deflection of the parent particle beam and full compensation of the dispersion is proposed. In this scheme the decay part of the channel is deflected with respect to the direction of the primary proton beam aiming at the target. The main computational characteristics of the neutrino beam at the far detector at a distance of 2595 km from the end of the decaying part of the channel as well as the parameters of the parent π mesons at the beginning of the decaying part are discussed.

Pulsed laser directed energy deposition of super duplex stainless steel: engineering microstructure and improving mechanical properties

Alloys developed by fusion-based additive manufacturing often suffer from the coarse columnar grain structure and their effect on properties. This work involves the practical application of pulsed laser in laser-based directed energy deposition (DED-LB) of super duplex stainless steel which led to engineering the microstructure, improving the mechanical properties, and changing the dominant texture. Pulsed laser DED-LB (here P-DED) with laser spot sizes of 1 and 2 mm and different frequencies were used. Refine-grained ferritic steels containing porosity were produced when using a small laser spot size. Ferrite-to-austenite (α → γ) transformation was constrained to the grain boundaries under the effect of small excitation overlaps. Using broader laser, higher energy input, and ultra-short pulse intervals encouraged γ nucleation, promoted the density, and decreased the content of undesirable oxides that are typically formed during the conventional DED-LB (here C-DED). The local ferritization under the fusion lines of C-DED was avoided by P-DED. Directionally solidified α, extending into several layers, was inhibited by P-DED with optimum overlap. Enhanced supercooling resulted in an in situ grain refinement and columnar-to-equiaxed morphological transition. Defect-free microstructure and effective distribution of interphase boundary surface by P-DED, with a laser spot size of 2 mm and ⁓99% excitation overlap, largely improved the toughness and elongation (with acceptable strength). Pulse-induced convection and isotropic heat flow during P-DED with smaller laser spot size subsided the trend of preferred orientation. However, an alignment of < 001 > α with deposition direction during P-DED with the broader laser preserved the typical {001} < 100 > solidification texture and, consequently, the transformation texture.

Tunable Characteristics of Optical Frequency Combs from InGaAs/GaAs Two-Section Mode-Locked Lasers.

We observed tunable characteristics of optical frequency combs (OFCs) generated from InGaAs/GaAs double quantum wells (DQWs) asymmetric waveguide two-section mode-locked lasers (TS-MLLs). This involves an asymmetric waveguide mode-locked semiconductor laser (AWML-SL) operating at a center wavelength of net modal gain of approximately 1.06 µm, which indicates a stable pulse shape, with the power-current(P-I) characteristic curve revealing a small difference between forward and reverse drive currents in the gain region. Under different operating conditions, the laser exhibits the characteristics of OFCs. And the pulse interval in the timing and the peak interval in the frequency domain show a periodic alternating change trend with the increase in the gain current. This tunable characteristic is reported for the first time. The study demonstrates the feasibility of generating tunable optical combs using a monolithic integrated two-section mode-locked semiconductor laser (MI-TS-MLL). This has important reference value for the application of OFCs generated from MI-TS-MLLs or integrated optical chips.

Phase-coded coherent microwave pulse generation based on an actively mode-locked optoelectronic parametric oscillator.

An approach for generating phase-coded coherent microwave pulse trains at high frequencies is proposed and demonstrated based on an actively mode-locked optoelectronic parametric oscillator (AML-OEPO), where an electrical mixer is inserted into the cavity of an optoelectronic oscillator (OEO) to achieve both mode locking and parameter oscillation. The driving signal applied to the mixer is a low-frequency sinusoidal signal with voltage polarity coding, where the frequency is the same as the free spectral range (FSR) of the OEO cavity, and the duration of each voltage polarity coding bit is identical to the loop delay. As a result, phase-coded coherent microwave pulse trains can be generated, where the pulse interval is equal to the loop delay due to the active mode locking effect, and the phase coding period is equal to a multiple integer of the loop delay due to parameter oscillation. The enhancement of the signal period and the highly coherent characteristic are beneficial for breaking the contradiction between unambiguous detection range and ranging resolution in pulse radars. In the experiment, phase-coded microwave pulse trains with either 13-bit barker codes or 7-bit M codes are generated at 15.026 GHz. The autocorrelation calculation result of the phase-coded microwave pulse train with 13-bit barker codes shows a high peak-to-sidelobe ratio, verifying high coherence.

Burst-Mode Nd: YAG/Cr⁴⁺:YAG Laser With Tunable Pulse Chain Sequence and Intervals

Burst-Mode Nd: YAG/Cr⁴⁺:YAG Laser With Tunable Pulse Chain Sequence and Intervals

USING POWER MANAGEMENT AND DELAY MECHANISM IMPROVE THE PERFORMANCE OF OPTICAL FIBRE COMMUNICATION SYSTEM BY REDUCING FOUR WAVE MIXING

"This study examines the impact of four-wave mixing (FWM) on the performance of single-mode fibers (SMF). Using Optsim simulation software, a dispersion-compensating fiber (DCF) was implemented with varying dispersion and pulse intervals to analyze FWM behavior. The results show improved performance when power management techniques and time-domain delays are applied. The system's performance was evaluated using Q-factor and bit error rate (BER) metrics. "The system's performance was evaluated using Q-factor and bit error rate (BER) metrics."

Optimization of Reservoir Computing Utilizing Interfered Spin Waves

Reservoir computing is a learning model that enables low-cost and fast learning compared to conventional deep learning. It enables physical implementation by replacing the reservoir part with a physical device that possesses nonlinearity, short-term memory, and high dimensionality. In particular, it was theoretically predicted that spin wave interference can perform highly efficient reservoir computing in micromagnetic simulations,[1] and it was experimentally verified by the present authors.[2] Whereas the computational performance was suggested to vary significantly depending on the interval of input voltage pulses used for spin wave excitation and the applied magnetic field intensity, the details were unclear to date. Therefore, we expanded the measurement range to investigate detailed mechanism of the system and to explore untouched high performance in the study.We use a device fabricated on the surface of a single crystal, as shown in Fig. (a), then we performed one of the most important prediction benchmark tasks, the Nonlinear Autoregressive Moving Average (NARMA) model. Since it has been found that utilizing the nonlinear interference of spin waves through multi-detection demonstrates high performance, in this study, we utilized both Detection A and Detection B. We evaluated the prediction error of NARMA10, which requires short-term memory up to 10 steps, by varying the applied magnetic field and the interval of input voltage pulses under measurement conditions. As shown in Fig. (b), the comparison between the target waveform and the output waveform during training and testing under the conditions of a magnetic field of 182 mT and a pulse interval of 23.6 ns shows a good match, at that time, the error was 0.183 during the testing phase. Next, we examined the detailed condition dependence in NARMA10. As indicated in Fig. (c), high performance is obtained in the region where the pulse interval is between 20 and 30 ns, while the performance was low in the region below 19.3 ns, particularly in the strong magnetic field range from 188 mT to 200 mT. We will discuss the condition dependence with the other NARMA models like NARMA2. Additionally, we will discuss in detail the dependence on input pulse intervals, along with evaluations of short-term memory capacity and nonlinearity. This work was in part supported by Innovative Science and Technology Initiative for Security Grant Number JPJ004596, ATLA, Japan and JST PRESTO (JPMJPR23H4).【Reference】[1] Nakane et al., IEEE Access 6, 4462 (2018).[2] Namiki et al., Adv. Intell. Syst. 5, 2300228 (2023). Figure 1

Pulse Oxidation to Mitigate Carbon Monoxide Poisoning in Electrochemical Hydrogen Pumps

Electrochemical hydrogen pumps (EHP) play a pivotal role in developing clean and sustainable energy systems, with applications ranging from hydrogen transportation to stationary power generation. However, the presence of carbon monoxide (CO) in the hydrogen stream can pose a significant challenge, leading to catalyst poisoning and decreased pump efficiency. This work introduces a novel and effective strategy to mitigate carbon monoxide poisoning in EHPs using pulse oxidation. Pulse oxidation involves periodically applying a positive increase in current to the electrode surface to create an anode overpotential that oxidizes CO from the catalyst surface. This technique offers a dynamic and precise means of selectively removing CO impurities from the hydrogen stream. Tailoring the current pulses to the specific electrochemical characteristics of CO can achieve targeted removal without compromising the overall pump performance. The study explores the influence of CO gas feed rate, pulse width, operating current, and pulse interval on EHP performance. Results show that optimizing these parameters significantly impacts separation efficiency, energy efficiency, and power consumption. This strategy promises to improve the reliability and longevity of EHPs in real-world applications. By effectively addressing carbon monoxide poisoning, pulse voltammetry opens new avenues for developing robust and efficient hydrogen pumping systems, contributing to the broader goal of establishing hydrogen as a clean energy carrier in a sustainable future.

Optical pulse generation with programmable positions in an actively mode-locked optical cavity.

A novel, to our knowledge, approach for generating optical pulses with programmable positions in an actively mode-locked (AML) optical cavity is proposed and experimentally demonstrated. In the AML, active mode locking occurs when the cavity gain exceeds one, and the cavity round trip time equals integer multiples of the repetition period of the electrical driving signal. The generated optical pulses are present at the positions where the optical cavity operates at its maximum transmission points. By periodically controlling the cavity gain with the driving signal, the maximum transmission points can be manipulated using a periodic arbitrary waveform, allowing the positions of the generated optical pulses within one round trip time to be programmed. Thanks to the superposition of the circulating optical field within the optical cavity, the pulse width of the generated pulses can be greatly compressed. In a proof-of-concept experiment, optical pulses with programmable pulse numbers, pulse intervals, and pulse position distributions in one period are generated by programming the driving signals. Optical pulse compression is also successfully verified. Optical pulses with an approximate 34-ps pulse width, ultra-low pulse interval (about 200 ps), and linear positional distribution are achieved.

Aquariums as Research Platforms: Characterizing Fish Sounds in Controlled Settings with Preliminary Insights from the Blackbar Soldierfish Myripristis jacobus

This study highlights the potential of aquariums as research platforms for bioacoustic research. Aquariums provide access to a wide variety of fish species, offering unique opportunities to characterize their acoustic features in controlled settings. In particular, we present a preliminary description of the acoustic characteristics of Myripristis jacobus, a soniferous species in the Holocentridae family, within a controlled environment at a zoological facility in the Canary Islands, Spain. Using two HydroMoth 1.0 hydrophones, we recorded vocalizations of the blackbar soldierfish in a glass tank, revealing a pulsed sound type with a peak frequency around 355 Hz (DS 64), offering a more precise characterization than previously available. The vocalizations exhibit two distinct patterns: short sequences with long pulse intervals and fast pulse trains with short inter-pulse intervals. Despite some limitations, this experimental setup highlights the efficacy of cost-effective methodologies in public aquariums for initial bioacoustic research. These findings contribute to the early stages of acoustic characterization of coastal fishes in the western central Atlantic, emphasizing the value of passive acoustic monitoring for ecological assessments and conservation efforts. Moreover, this study opens new avenues for considering the acoustic environment as a crucial factor in the welfare of captive fish, an aspect that has largely been overlooked in aquarium management.

Heteroepitaxy of ε‐Ga2O3 thin film for artificial synaptic device

AbstractEmerging‐wide bandgap semiconductor Ga2O3 shows distinct characteristics for optoelectronic applications and a stable crystal phase of Ga2O3 is highly desired. Herein, we have first reported a metal‐semiconductor‐metal structure photonic synaptic device based on the ε‐Ga2O3 thin film. The ε‐Ga2O3 epilayer is grown on the c‐sapphire with a low temperature nucleation layer, which presents a crystal orientation relationship with the c‐sapphire (ε‐Ga2O3 &lt;010&gt; // c‐sapphire &lt;1–100&gt; and ε‐Ga2O3 &lt;001&gt; // c‐sapphire &lt;0001&gt;). The ε‐Ga2O3 photonic device was stimulated by UV pulses at different pulse widths, pulse intervals, and reading voltages. Under the UV pulse excitation, the photonic device exhibits primary synaptic functions including excitatory postsynaptic current, short term memory, pair pulse facilitation, long term memory, and STM‐to‐LTM conversion. In addition, stronger and repeated stimuli can naturally contribute to the higher learning capability, thus prolonging the memory time.

Substrate and Step Rate Dependence Electrodeposition of Nickel–Cobalt–Molybdenum–Phosphorous Alloy for Efficient Hydrogen Evolution Reaction

Understanding the hydrogen economy involves recognizing the crucial role of water‐splitting in producing green, clean, and carbon‐free hydrogen. In that respect, the role of catalyst is very important as it enhances the reaction rate and efficiency, making hydrogen production more viable and sustainable. Herein, nickel–cobalt–molybdenum–phosphorous (Ni–Co–Mo–P) alloy has shown efficient catalysis properties for hydrogen evolution reaction (HER) in an alkaline medium. The quaternary alloys are directly grown on different substrates like nickel sheet, copper sheet, and stainless‐steel sheet by employing a simple pulse electrodeposition method. The method is conducted with a pulse interval time of 15 s at various pulse rates while maintaining the pH of 4 at room temperature. The alloy deposition is performed at a potential range from −1.5 V to −0.15 V (vs Ag/AgCl). The electrodeposition of the alloy in different substrates is first established with X‐Ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), and Raman spectroscopy. The deposited quaternary alloy exhibits the lowest overpotential of −163 mV at 10 mA cm−2 for copper substrate with a Tafel slope of 154 mV dec−1. The microcrystalline structure or amorphous nature and the rough grain surface of Ni‐Co‐Mo‐P alloys have characterized by XRD and scanning electron microscopy micrograph, respectively.

Experimental Analysis of EDM Parameters on D2 Die Steel Using Nano-aluminum Composite Electrodes

This paper presents an experimental study on the electrical discharge machining (EDM) of AISI D2 die steel using an Al-Ni composite electrode. The investigation focuses on the influence of input parameters like current, pulse duration, and pulse interval, on key output parameters such as material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR). EDM oil was employed as the dielectric fluid. Grey relational analysis (GRA) was utilized for designing and conducting the experiments using the Taguchi L9 method. The ANN model showed excellent predictive accuracy with a perfect correlation coefficient (R) of 1.00, indicating strong capability in forecasting MRR based on machining parameters. GRA further confirmed that higher current settings and longer pulse-off times effectively reduce tool wear, suggesting that the ANN model accurately reflects the conditions that minimize TWR. The ANN model achieved strong predictive accuracy for SR, with high correlation coefficients, although with slightly higher mean squared error (MSE) in testing.

Enhancing Surface Quality and Tool Longevity in EDM of D2 Steel Using Copper Composite Tools

Hard material machining and die manufacture are the main applications for electrical discharge machining (EDM). For EDM, conventional electrode materials include graphite, steel, brass, pure copper, and alloys based on copper. Unfortunately, excessive tool wear is a common problem with these materials, which raises the cost of machining. In this investigation, hardened D2 steel was machined using a composite tool made of 90% copper and 10% silicon carbide. The powder metallurgy method was used to create the composite tool. Surface roughness (SR) and electrode wear rate (EWR) were compared to a number of process variables. For experimentation, a response surface methodology based on CCD design in design of experts software was used. SR and electrode wear rate models were created using the CCD approach. Utilizing analysis of variance, the most important factors and their effects on EWR and SR were determined. The lowest tool wear rate of 0.39 gm/min is achieved with a current of 5 Amps, a pulse duration of 100 µs, and a pulse interval of 10 µs with an R2 of 0.9957, which accounts for 99.57% of the variability, the tool wear rate model fits the data very well and obtained lowest surface roughness of 2.8 µm.

A Highly Efficient Compressive Sensing Algorithm Based on Root-Sparse Bayesian Learning for RFPA Radar

Off-grid issues and high computational complexity are two major challenges faced by sparse Bayesian learning (SBL)-based compressive sensing (CS) algorithms used for random frequency pulse interval agile (RFPA) radar. Therefore, this paper proposes an off-grid CS algorithm for RFPA radar based on Root-SBL to address these issues. To effectively cope with off-grid issues, this paper derives a root-solving formula inspired by the Root-SBL algorithm for velocity parameters applicable to RFPA radar, thus enabling the proposed algorithm to directly solve the velocity parameters of targets during the fine search stage. Meanwhile, to ensure computational feasibility, the proposed algorithm utilizes a simple single-level hierarchical prior distribution model and employs the derived root-solving formula to avoid the refinement of velocity grids. Moreover, during the fine search stage, the proposed algorithm combines the fixed-point strategy with the Expectation-Maximization algorithm to update the hyperparameters, further reducing computational complexity. In terms of implementation, the proposed algorithm updates hyperparameters based on the single-level prior distribution to approximate values for the range and velocity parameters during the coarse search stage. Subsequently, in the fine search stage, the proposed algorithm performs a grid search only in the range dimension and uses the derived root-solving formula to directly solve for the target velocity parameters. Simulation results demonstrate that the proposed algorithm maintains low computational complexity while exhibiting stable performance for parameter estimation in various multi-target off-grid scenarios.

A wireless, battery-free device for electrical neuromodulation of bladder contractions

Lower urinary tract dysfunction (LUTD) is a prevalent condition characterized by symptoms such as urinary frequency, urgency, incontinence, and difficulty in urination, which can significantly impair patient's quality of life and lead to severe physiological complications. Despite the availability of diverse treatment options, including pharmaceutical and behavioral therapies, these approaches are not without challenges. The objective of this study was to enhance treatment options for LUTD by developing a wireless, battery-free device for managing bladder contractions. We designed and validated a compact, fully implantable, battery-free pulse generator using the magnetic induction coupling mechanism of wireless power transmission. Weighing less than 0.2 g and with a volume of less than 0.1 cubic centimeters, this device enables precise stimulation of muscles or neurons at voltages ranging from 0 to 10 V. Wireless technology allows real-time adjustment of key stimulation parameters such as voltage, duration, frequency, pulse width, and pulse interval. Our findings demonstrate that the device effectively controlled bladder contractions in mice when used to stimulate the Major Pelvic Ganglion (MPG). Additionally, the device successfully managed micturition in mice with bilateral transection of the pudendal nerve. In conclusion, the development of this innovative wireless pulse generator provides a safer and more cost-effective alternative to conventional battery-powered neurostimulators for bladder control, addressing the limitations of such devices. We anticipate that this novel technology will play a pivotal role in the future of electrical stimulation therapies for voiding dysfunctions.

EDM-Grinding composite machining and drilling of polycrystalline diamond tool

ABSTRACT Polycrystalline diamond (PCD) is widely used for micro tools due to its high hardness and wear resistance. However, micro PCD tools face challenges in machining with high accuracy and efficiency. Therefore, electrical discharge machining grinding (EDM-grinding) composite machining was proposed. The effects of pulse discharge parameters on surface quality and microhole drilling performance of PCD tool were investigated. The results show that the surface roughness of helix flute and flank face of the fabricated PCD tool were 0.125 µm and 0.158 µm, respectively, as well as the inner wall roughness achieved 0.331 µm after drilling of microhole. The average current displayed a greater effect on the machining quality of PCD tools, with tool breakage in excessive average current. The preferred pulse discharge parameters were determined as an open-circuit voltage of 95 V, an average current of 1400 mA, a pulse width of 400 ns, and a pulse interval of 2000 ns.