Wave Amplitude Research Articles

Biological Basis and Computer Vision Applications of Image Phase Congruency: A Comprehensive Survey.

The concept of Image Phase Congruency (IPC) is deeply rooted in the way the human visual system interprets and processes spatial frequency information. It plays an important role in visual perception, influencing our capacity to identify objects, recognize textures, and decipher spatial relationships in our environments. IPC is robust to changes in lighting, contrast, and other variables that might modify the amplitude of light waves yet leave their relative phase unchanged. This characteristic is vital for perceptual tasks as it ensures the consistent detection of features regardless of fluctuations in illumination or other environmental factors. It can also impact cognitive and emotional responses; cohesive phase information across elements fosters a perception of unity or harmony, while inconsistencies can engender a sense of discord or tension. In this survey, we begin by examining the evidence from biological vision studies suggesting that IPC is employed by the human perceptual system. We proceed to outline the typical mathematical representation and different computational approaches to IPC. We then summarize the extensive applications of IPC in computer vision, including denoise, image quality assessment, feature detection and description, image segmentation, image registration, image fusion, and object detection, among other uses, and illustrate its advantages with a number of examples. Finally, we discuss the current challenges associated with the practical applications of IPC and potential avenues for enhancement.

Instability and breakup of rayleigh-plateau jets with capillary wave induced by electrowetting-on-dielectric

This paper discusses the lateral disturbances of vertical liquid flow enhancement using electrowetting-on-dielectric (EWOD) technique, which effectively reducing the breakup length of the liquid flow and minimizing the formation of satellite droplets. The EWOD technology is characterized by its minimal space occupation and low energy consumption. The successful implementation of the EWOD phenomenon relies on the formation of a three-phase contact line (TPCL) between the electrodes and the liquid, and the novel EWOD tube structure design provides an extended TPCL, enhancing the amplitude of capillary waves. Through experimental and theoretical analysis, this paper identifies key parameters affecting the liquid breakup process, such as the gap depth, angle of the EWOD tube, EWOD voltage amplitude, and frequency of the AC electrical signal. The research results indicate that the proposed EWOD tube responds rapidly and can consistently and stably manage liquid breakup and reduce the number of satellite droplets.

Laser Driven Wake Wave in Pair-ion Electron Plasma with Inclusion of Ion Dynamics

Abstract The generation of laser driven plasma wake wave has been investigated in hydrogen 
 pair-ion electron plasma. The consideration of 
 dynamics of the positive and negative ion pair have been adopted. Inclusion of the ion motion
 has the effect of modifying the electric field and density profiles of the wake wave.
 This has been demonstrated by observing the variation of the 
 electron density and electric field profiles with the change in positive ion/ negative ion concentration.
 High density spikes and sawtooth like electric field profiles (indication of wave breaking) are observed 
 to transform into sinusoidal electric field profile and low amplitude density profile 
 when the positive ion density in the plasma system is kept higher. Furthermore, we observe the variation of 
 the electric field amplitude of the wake wave with the laser pulse width. This feature is the indication of 
 the possibility of hybrid acceleration (Direct Laser Acceleration and wake field acceleration) 
 of accelerated beam. The results are quite relevant in the field Laser plasma interaction field 
 in experimental physics and also in planetary
 environment.

Clinical characteristics and analysis of vestibular-evoked myogenic potentials in patients with sudden sensorineural hearing loss in different ages.

Numerous studies have found that patients experiencing sudden sensorineural hearing loss (SSHL), with or without accompanying vertigo, often show impaired vestibular function. However, there is a dearth of studies analyzing vestibular-evoked myogenic potentials (VEMPs) in SSHL patients across various age groups. To investigate vestibular condition in SSHL patients across various age demographics. Clinical data of 84 SSHL patients were investigated retrospectively. Audiometry, cervical vestibular evoked myogenic potentials (c-VEMPs), and ocular vestibular evoked myogenic potentials (o-VEMPs) were conducted on these patients. Parameters assessed included the latencies of P1 and N1 waves, as well as the amplitudes of P1-N1 waves. Moreover, the study evaluated the influence of factors such as sex, affected side, configuration of hearing loss, and presence of accompanying vertigo. Among the 84 SSHL patients, no significant differences were observed among the three groups in terms of gender, affected side, and the presence or absence of vertigo. Group II (aged 41-60 years) had the highest number of SSHL cases. The rates of absent o-VEMPs in the affected ears were 20.83%, 31.58%, and 22.72% for the three age groups, respectively, with no statistically significant difference among them. The rates of absent c-VEMPs in the affected ears were 8.3%, 34.21%, and 18.18% for the three age groups, respectively, with significant differences. In the unaffected ears, there were differences observed in the extraction rates of o-VEMPs in the unaffected ears among the age groups. In the three age groups, no significant differences were noted in the three age groups in the latencies of P1 and N1 waves or in the amplitude of N1-P1 waves for c-VEMPs and o-VEMPs, either on the affected side or on the unaffected side, across the three age groups. The extraction rate of VEMPs is more valuable than parameters. Regardless of the presence of vertigo, vestibular organs are involved in SSHL. Notably, SSHL patients aged 41-60 appear more susceptible to damage to the inferior vestibular nerve and saccule.

Multifield stochastic dynamics in GUT hybrid inflation without monopole problem and with gravitational wave signatures of GUT Higgs representation

We revisit the hybrid inflation model within the framework of the Grand Unified Theory (GUT), focusing on cases where the waterfall phase transition extends over several e-foldings to dilute monopoles. Considering the stochastic effects of quantum fluctuations, we demonstrate that the waterfall fields (i.e., GUT Higgs) maintain a nonzero vacuum expectation value around the waterfall phase transition. By accurately accounting for the number of degrees of freedom of the GUT Higgs field, we establish that these fluctuations can produce observable gravitational waves without leading to an overproduction of primordial black holes. The amplitude of these gravitational waves is inversely proportional to the degrees of freedom of the waterfall fields, thereby providing a unique method to probe the representation of the GUT Higgs.

Modulational instability and chirped modulated wave, chirped optical solitons for a generalized (3+1)-dimensional cubic-quintic medium with self-frequency shift and self-steepening nonlinear terms

We consider a generalized (3+1)-dimensional nonlinear Schrödinger with cubic-quintic nonlinear and self-frequency shift and self-steepening terms. We disrupt the plane wave to study the stability of the wave in this media. We examine how various factors—such as the amplitude of the plane wave, cubic and quintic nonlinear terms, self-steepening, and self-frequency shift—affect the modulational instability (MI). Our findings reveal that the amplitude of the plane wave and the quintic nonlinear term can expand the MI bands and increase the amplitude of the MI growth rate. Conversely, the self-steepening and self-frequency shift terms exert opposite effects, narrowing the MI bands and reducing the amplitude of the MI growth rate. We investigate the existence of modulated chirped rational and polynomial Jacobi elliptic function solutions and chirped optical solitons.

Intracranial pulse pressure amplitude as an indicator of intracranial compliance: observations in symptomatic children with Chiari malformation type I.

Reduced intracranial compliance (ICC) may be an important factor in the pathophysiology of Chiari malformation type I (CM-I). However, direct measurement of ICC is controversial because of its invasiveness, particularly in children. Instead, ICC may be estimated from continuous measurements of intracranial pressure (ICP), where the metric mean wave amplitude (MWA) has been found to be more useful as a surrogate marker of ICC than mean ICP. This observational study investigated the distribution of MWA and mean ICP in symptomatic children with CM-I, as well as their association with clinical and radiological findings. From a consecutive series of children treated for CM-I at a single institution between 2006 and 2023, the authors analyzed ICP scores in those who underwent an overnight preoperative ICP recording in which MWA was calculated. Clinical and radiological data were retrieved from the patient records. Thirty-seven children (mean age 12.4 ± 3.6 years) with symptomatic CM-I were identified. From the overnight ICP measurements, the average MWA was 5.2 ± 1.3 mm Hg: 56% of children had an abnormal MWA (> 5 mm Hg) and 33% had a borderline MWA (4-5 mm Hg). In contrast, the average mean ICP was 9.7 ± 4.1 mm Hg: 8% of children had an abnormal mean ICP (> 15 mm Hg) and 41% had a borderline mean ICP (10-15 mm Hg). Thus, more children were found to have an abnormal MWA than an abnormal mean ICP (p < 0.001). MWA was significantly higher in the subgroup of children with medullary compression in the foramen magnum, as seen on MRI, than in those without (5.6 ± 1.0 mm Hg vs 4.7 ± 1.4 mm Hg, p = 0.03), whereas a similar difference was not observed for mean ICP (9.9 ± 4.6 mm Hg vs 9.7 ± 3.7 mm Hg, p = 0.889). In this cohort of symptomatic children with CM-I, MWA was more frequently abnormal than mean ICP, with a clinically significant discrepancy in half of the patients. Moreover, MWA was significantly higher in patients with medullary compression. Based on these findings, the authors' interpretation is that in children with CM-I, the ICC may be reduced, as indicated by increased MWA, even though the mean ICP is within normal thresholds.

F wave analysis based on the compound muscle action potential scan.

Conventional F wave analysis involves a relatively uniform physiological environment induced by supramaximal stimulations. The F wave characteristics in a dynamic physiological condition, however, are rarely investigated. This study aimed to improve understanding of F wave properties in the more dynamic process by introducing a novel method to analyze F waves based on the compound muscle action potential (CMAP) scan technique. Twenty four healthy subjects participated in the study. The CMAP scan was applied to record muscle responses in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles, respectively. F wave characteristics including mean F wave amplitude and latency (F-M latency), persistence and activating threshold were quantified. An average of 200 F waves per muscle were obtained from the CMAP scan recording. Weak to moderate correlations between F wave amplitude and stimulating intensity were observed in most of the APB (19 muscles; r = 0.33 ± 0.14, all p < .05) and ADM (23 muscles, r = 0.46 ± 0.16, all p < .05) muscles. Significantly longer mean F latency and lower activating F-threshold were found in the ADM muscles (F-M latency: APB: 25.43 ± 2.39 ms, ADM: 26.15 ± 2.32 ms, p < .05; F-threshold: APB: 7.68 ± 8.96% CMAP, ADM: 2.35 ± 2.42% CMAP, p < .05). This study introduces new features of F waves using the CMAP scan technique and identifies differences of F wave characteristics between the hand muscles. The CMAP scan based F waves analysis can be combined with the motor unit number estimation to assess functional alterations in motor neurons in neurological disorders.

Proportional relations between the wave number and amplitude of spiral waves near Neimark-Sacker bifurcations

Abstract The spatiotemporal distribution patterns of interacting populations are broadly accepted as a pivotal factor in sustaining species diversity. Spiral waves represent common spatiotemporal patterns observed in ecosystems and biological systems, encompassing both continuoustime and discrete-time systems. The study of the dynamics and regulation of spiral waves in continuous-time systems, often observed in the vicinity of Hopf bifurcations, has been comprehensively examined. However, the dynamical characteristics and rules governing spiral waves near Hopf bifurcations in discrete-time systems, also named Neimark-Sacker bifurcations, are still not fully understood. Here, we investigate spiral waves in a discrete-time predator-pest model caused by a Neimark-Sacker bifurcation. Our results suggest a linear relationship between the amplitude and wave number of spiral waves near the Neimark-Sacker bifurcation. At last, we propose a model that can describe the behaviors of spiral waves in discrete-time systems near Neimark-Sacker bifurcations. Our findings illuminate the process of pattern formation in discrete-time systems, offering potential insights for forecasting and managing pest distribution.

P-304 Quantitative analysis of uterine peristalsis using optical flow for motion quantification in women with moderate/severe adenomyosis undergoing frozen-thawed embryo transfer following prolonged downregulation with GnRHanalogue

Abstract Study question What is the impact of prolonged downregulation with GnRH analogue (GnRHa) on uterine peristalsis in women with moderate/severe adenomyosis undergoing frozen-thawed embryo transfer? Summary answer Women with moderate/severe adenomyosis have lower coordination of uterine peristalsis and myometrial contractility; prolonged downregulation with GnRHa appears to offer benefit. What is known already Adenomyosis can adversely reduce the chance of pregnancy in women undergoing assisted conception, with altered uterine peristalsis proposed as a mechanism. We aimed to i) develop an objective tool to quantify uterine peristalsis on transvaginal sonography(TVS) using an algorithm based on optical flow for wave motion quantification, ii) compare uterine peristalsis between women with a normal uterus and women with moderate/severe adenomyosis, iii) evaluate the impact of prolonged downregulation with GnRH analogue for 6 weeks vs 1 week on uterine peristalsis in women with moderate/severe adenomyosis undergoing frozen-thawed embryo transfer within the MODA RCT (Modified Downregulation for Adenomyosis). Study design, size, duration Prospective observational cohort study(July 2021–Jan 2024) in women with moderate/severe adenomyosis(n = 26) and a normal uterus(n = 40) having TVS during assisted conception. Participants/materials, setting, methods We included women with moderate/severe adenomyosis or a normal uterus undergoing assisted conception.TVS was performed at baseline(BL),day 6-10 of ovarian stimulation(OS) and day of embryo transfer(ET)by three observers(A/B/C)to assess inter-/intra-observer agreement. TVS recordings(n = 146) were stored offline for optical flow analysis using 3D Slicer(Ver. 4.11). Pixel-level displacements for points at endometrial-myometrial junction(EMJ)and myometrium were used to compute frequency(f) and amplitude(u) by fitting to the 2D-wave equation, fit error was taken as a measure of coordination. Main results and the role of chance We recruited 66 women with moderate/severe adenomyosis (n = 26) or a normal uterus (n = 40) undergoing assisted conception. Uterine peristalsis at the EMJ in women with adenomyosis showed a significantly poorer fit with the ideal wave equation and a significantly higher fit error compared to women with normal uterus at all time points (BL (+ 0.649), OS (+ 0.630), ET (+ 0.685) (n = 66, p&amp;lt;0.001), indicating lower coordination of uterine peristalsis in women with adenomyosis compared to women with a normal uterus. Fit error of myometrial contractility was also significantly lower in women with adenomyosis at all time points (BL (+ 0.656), OS (+ 0.510) and ET (+ 0.639) (n = 66, p &amp;lt; 0.001). There was no significant difference in wave amplitude or frequency in women with adenomyosis compared to women with a normal uterus (p &amp;gt; 0.06). Women with moderate/severe adenomyosis exposed to prolonged downregulation with GnRH analogue for 6 weeks had lower fit error of uterine peristalsis (UP) and myometrial contractility (MC) on the day of embryo transfer compared to women receiving 1 week GnRH analogue (UP ET(+0.615) (n = 19, p = 0.058) (MC ET(+4.28) (n = 19, p &amp;lt; 0.05). Inter- and intra-observer agreement was found to be moderate to substantial across all wave features(ICC 0.58-0.79). Limitations, reasons for caution There is a need to recruit a larger cohort of patients and correlate wave features with clinical outcomes to increase the robustness of the conclusions drawn in this study. Wider implications of the findings Our algorithm for wave motion quantification offers an objective,reproducible measuring tool to quantify uterine peristalsis with potential for wide clinical application.Women with adenomyosis have higher fit error and lower coordination of uterine peristalsis and myometrial contractility,which may account for their reduction in chances of conception.Prolonged GnRHa appears to offer benefit. Trial registration number N/A

Intimate relationships regulate female brain activity in a competitive context: evidence from EEG and functional connectivity analysis.

Competition is common in life, and intimate relationships are essential. Understanding how intimate relationships impact an individual's competitive process is crucial. This study explored the impact of competitor gender on female competition using electroencephalography analysis. The results revealed that females exhibited a smaller median of the absolute value of reaction time difference (DRT) between their partners and their competitors when their partners were absent compared to when their partners were present. Additionally, females showed greater average amplitudes of N2 posterior contralateral component (N2pc) and Late Positive Potential (LPP), increased activation of the alpha frequency band, and enhanced theta frequency band functional connectivity between the central parietal lobe and occipital lobe. Furthermore, when competing with individuals of the same gender as opposed to individuals of the opposite gender, females exhibited greater average amplitudes of percentage of wins and N2pc. A significant negative correlation was noted between the DRT and the average wave amplitudes of N2pc and LPP. These findings suggest that females are more engaged in competitive tasks when partners are not present and have improved decision-making when competing with same-gender individuals. This study provides evidence for the influence of lovers on female competition, helping females adapt to social competition and promoting healthy relationships.

Propagating kink waves in an open coronal magnetic flux tube with gravitational stratification: Magnetohydrodynamic simulation and forward modelling

In coronal open-field regions, such as coronal holes, there are many transverse waves propagating along magnetic flux tubes, which are generally interpreted as kink waves. Previous studies have highlighted their potential role in coronal heating, solar wind acceleration, and seismological diagnostics of various physical parameters. This study aims to investigate propagating kink waves, considering both vertical and horizontal density inhomogeneity, using 3D magnetohydrodynamic (MHD) simulations. We established a 3D MHD model of a gravitationally stratified open flux tube, incorporating a velocity driver at the lower boundary to excite propagating kink waves. Forward modelling was conducted to synthesise observational signatures of the Fe ix 17.1 nm line. Resonant absorption and density stratification both affect the wave amplitude. When diagnosing the relative density profile with velocity amplitude, resonant damping needs to be properly considered to avoid a possible underestimation. In addition, unlike standing modes, propagating waves are believed to be Kelvin-Helmholtz stable. In the presence of vertical stratification, however, the phase mixing of transverse motions around the tube boundary can still induce small-scale structures, partially dissipating wave energy and leading to a temperature increase, especially at higher altitudes. Moreover, we conducted forward modeling to synthesise observational signatures, which revealed the promising potential of future coronal imaging spectrometers such as MUSE in resolving these wave-induced signatures. Also, the synthesised intensity signals exhibit apparent periodic variations, offering a potential method for indirectly observing propagating kink waves with current extreme ultraviolet imagers.

Experimental Attempts of Using Modulated and Unmodulated Waves in Low-Frequency Acoustic Wave Flame Extinguishing Technology: A Review of Selected Cases

In practice, some undesired signals perceived as noise (because of the sound sensation) can effectively extinguish flames. This article provides information on the applicability of acoustic waves (a case of using sine waves and sine waves amplitude modulated by a square waveform) in low-frequency acoustic wave flame extinguishing technology based on experimental results obtained from a laboratory stand, which is a scientific novelty. The benefits of using deep neural networks for flame detection based on dedicated solutions developed through international cooperation are also recognized. In addition, the potential advantages of combining both technologies (use in fully automatic systems), limitations, open problems, and plans for further research are identified. The paper concludes that it is possible to extinguish flames as soon as they appear (firebreaks) and prevent large fires from breaking out. This feature may effectively reduce material losses and increase widespread safety.

Experimental study of the vertical structure of internal solitary waves in the continuous pycnocline

In order to reveal the complex structural characteristics of internal solitary waves (ISWs) in the actual ocean, an experimental study of the vertical structure of ISWs in the continuous pycnocline (a transition layer with sharp density changes) was conducted in a stratified fluid flume. The gravity collapse method was used to generate ISWs, and their wave-flow fields were measured using a coupled wave-flow measurement technique. The vertical structure of wave-flow fields was investigated as was the applicability of the Dubreil–Jacotin–Long (DJL) equation. The results show that the waveform of ISWs contains multiple isodensity lines that varied with fluid depth. The wave amplitude and wavelength of ISWs exhibited depth-dependent changes, which were negatively correlated. The vertical structure of the flow fields exhibited an approximate circular wave packet, with stronger horizontal flow than vertical flow. The larger the characteristic amplitude, the stronger the intensity of the flow field, and the faster the intensity of the vertical flow field increased. The applicability of the DJL equation was closely related to the stratified environment, with better agreement when the upper layer fluid constituted a larger ratio of the total fluid thickness.

The Distribution of Pc5 Ultralow-frequency Waves at Geostationary Orbit

Using GOES magnetometer data spanning over 30 yr, we study the distribution of Pc5 ultralow-frequency waves at geosynchronous orbit. The CLEAN algorithm was applied to detect narrowband Pc5 waves. This method was first used in astronomical radio interferometry, but has since been applied to many other areas. The algorithm allows for identification of multiple individual peaks within the same power spectral density. We found close to 30,000 events in each magnetic field component in field-aligned coordinates. With some exceptions, results were in agreement with previous studies. Wave occurrence along magnetic local time (MLT) was higher in the 18–23 MLT sector. However, the largest accumulated wave amplitudes were observed on the dayside, peaking close to local noon. As expected, wave amplitudes were larger during more active solar wind conditions. For the radial and parallel components, amplitudes were maximum at the interplanetary magnetic field clock angle of −30° to −45°. The resultant database of Pc5 ultralow-frequency wave events can be used to constrain radiation belt models, while the CLEAN method provides a unique technique to automatically detect narrowband plasma waves in the magnetosphere and beyond.

A Randomized Controlled Clinical Trial of Xingnao Kaiqiao Acupuncture Combined With Modern Rehabilitation Therapy in the Treatment of Cognitive Dysfunction After Acute Ischemic Stroke

Objective: To investigate the therapeutic effect of Xingnao Kaiqiao acupuncture combined with modern rehabilitation therapy on cognitive dysfunction after acute ischemic stroke (AIS). Methods: Totally 140 patients with cognitive impairment after AIS admitted to Sichuan Provincial Rehabilitation Hospital from September 2016 to May 2021 were included in this prospective randomized controlled trial. After admission, patients were randomly divided into the trial group and the control group based on a computer-generated random number table. Patients in the trial group were treated with Xingnao Kaiqiao acupuncture combined with modern rehabilitation therapy, and those in the control group were treated with modern rehabilitation therapy alone. Before and after treatment, Mini-Mental State Examination (MMSE) and Barthel index (BI) were used to evaluate the cognitive function and daily living activities, and event-related potentials (ERP) were also measured in both groups. Statistical analyses were performed to compare the results between the two groups. Results: Finally 135 patients were included, 67 in the trial group and 68 in the control group. After treatment, the MMSE score and BI were significantly improved in both groups as compared with those before treatment (both P &lt; .001). In the trial group, the BI and the MMSE subscores in the domains of orientation, registration, recall, and language were significantly higher than those in the control group (all P &lt; 0.05). The global MMSE score of the trial group was higher than that of the control group both after 2 and 4 weeks of treatment, and the differences were statistically significant (P = 0.000/0.001). In the analysis of time effect alone, time had significant effects on the MMSE score in both groups (P &lt; 0.001). After treatment, the latencies of P3 waves were significantly shorter and the amplitudes of P3 waves were significantly higher in the trial group as compared with the control group (both P &lt; 0.05). Conclusion: Xingnao Kaiqiao acupuncture combined with modern rehabilitation therapy may be associated with a better efficacy in treating cognitive dysfunction after AIS. The effect of Xingnao Kaiqiao acupuncture on ERP may play a role in the mechanism underlying such a therapeutic effect.

Strain waves on additively manufactured plates for an on-orbit impact detector concept

Orbital debris impacts on spacecraft are an emerging threat to space missions due to the exponential increase in the number of satellites orbiting the Earth. Debris characteristics (size, material, velocity, etc.) are not well known for the size range of 10 mm or less that is undetectable using Earth telescopes or radar observation. The objective of this research was to determine wether a concept designed to detect impact of particles in the ∼1 to 5 mm range, find the location of the impact, and characterize the impacting projectile (velocity, size, angle, density), is feasible.The paper describes the design, fabrication, and tests performed on “witness plates” (the concept) made of two parallel layers of additively manufactured aluminum and instrumented with sixteen gages, eight on each layer. Laboratory experiments have shown that the waves can be recorded and properly interpreted to find location of impact, sound speed in the plate, and to estimate impact velocity. It was shown analytically that the amplitude of the first strain wave that propagates from the impact point is expected to decay as 1/r. This was observed as well in the signals recorded in the experiments. CTH computations were performed during the pre-test design phase and the post-test analysis phase. In fact, the numerical simulations have been key and pervasive in this research effort as they provided invaluable insight for the initial design and the correct interpretation of signal anomalies seen during the tests. Additionally, the computations confirmed the 1/r law derived analytically, i.e. that the assumptions for the derivation were justified. The main conclusions of the research are that, for a normal impact, the 1/r law for front gages can be easily used to determine the diameter of the impactor. It is possible that the back gages could be used to determine the density of the impactor as well. Finally, it was shown that oblique impacts generate an expected assymetry in the signals recorded. Though this aspect should be investigated further, the assymetry is probably uniquely related to the impact angle, which could provide the angle information.

Longitudinal changes in retinal ganglion cell function in optic pathway glioma evaluated by photopic negative response

Photopic negative response (PhNR), an index of retinal ganglion cell (RGC) function, is impaired in patients with optic pathway gliomas (OPGs). The aim of this longitudinal study was to evaluate whether PhNR deteriorates over time in OPG patients. Fourteen pediatric patients affected by OPG (4 males and 10 females, mean age 12.4 ± 5.7 years, 8 with neurofibromatosis type 1 [NF1]) with ≥ 12 months of follow-up and ≥ 2 evaluations, were included in this retrospective study. All patients received chemotherapy and/or OPG surgical resection, at least 5 years prior to the study. At baseline, all patients underwent a complete ophthalmological examination. Follow-up included clinical examination and PhNR measurements as well as brain MRI (according to pediatric oncologist indications) every 6 or 12 months. Mean follow-up duration was 16.7 ± 7.5 months (range 12-36 months). Photopic electroretinograms were elicited by 2.0 cd/m2 Ganzfeld white flashes presented on a steady 20 cd/m2 white background. The PhNR amplitude was measured as the difference between baseline and the maximal negative amplitude (minimum) of the negative wave, following the photopic b-wave. Compared to baseline, mean PhNR amplitude was significantly decreased at the end of follow-up (p =0.008). NF1-related OPGs exhibited a decline in PhNR amplitude (p =0.005) and an increase in PhNR peak-time during the follow-up (p =0.013), whereas sporadic OPGs showed no significant changes. Tumor size remained stable in all patients on MRI. PhNR amplitude decreased over the observation period, suggesting progressive RGC dysfunction in NF1-related pediatric OPGs, despite stable size on MRI imaging. PhNR could serve as a non-invasive objective tool for assessing longitudinal changes in RGC function in the clinical management of childhood OPG.

The feasibility of atrial Fibrillatory wave amplitude in predicting ablation outcomes in persistent atrial fibrillation

BackgroundAtrial fibrosis has a significant impact on the success rate of catheter ablation (CA) treatment of atrial fibrillation (AF). The fibrotic tissues could be reflected by the amplitude of the fibrillatory wave (F-wave). Methods and Results704 patients with persistent AF and at least 1-year follow-up after CA were included as the internal group. 101 patients from another hospital were used as the external validation cohort. A 12‑lead ECG was performed before CA and the maximum FWA in three ECG leads (aVL, aVF, V1) were measured. The FWA score (0 to 6 points according to the amplitude range of the three leads) of each patients was calculated. Five models including clinical features, FWA score, CHA2DS2-VASc score, APPLE score and the fusion of clinical features and FWA score were built. The FWA score was superior to the model constructed by clinical variables, CHA2DS2-VASc score and APPLE score. It not only had good predictive performance for AF recurrence, with an AUC value of 0.812 (95% CI 0.724–0.900), but also showed a significant predictive value for the recurrence rate according to F-wave amplitude. In the external validation cohort, the FWA score showed similar results (AUC 0.768, 95% CI 0.672–0.865). ConclusionsThe present study reveals the significant predictive value of the FWA score for persistent AF ablation recurrence.

Numerical investigation of rock-breaking mechanisms and influencing factors of different PDC cutters during rotary percussion drilling

While drilling deep or ultra-deep wells in hard rock formations, there are significant problems such as easy wear of drilling cutters and a low rate of penetration (ROP), and rotary percussion drilling technology is one of the essential techniques for improving drilling efficiency. However, there is currently limited research on the compatibility of rotary percussion drilling tools, polycrystalline diamond compact (PDC) cutters, and hard rock formations. Considering the motion mechanism of rotary percussion drilling tools, a three-dimensional rock-breaking numerical model was established for different cutters (planar, axe-shaped, and triple-ridged) under impact loads. Penetration depths, cutting widths, and rock-breaking volumes of different cutters under static and dynamic load coupling were analyzed. Changes in tensile, compressive, and shear stresses during the cutter rock-breaking process were compared, revealing the different cutter rock-breaking mechanisms under impact loads. The cutter rock-breaking laws under different impact amplitudes and frequencies were analyzed quantitatively, and the differences in rock-breaking effects of different cutters under various geological conditions were assessed. The results indicated that cutter penetration depth during rotary percussion drilling could be increased by 16.04% compared to that during conventional drilling. Under the same impact load, the rock-breaking effects of different cutters on hard and soft rocks exhibited similar variation patterns. The penetration depth followed the order axe-shaped > triple-ridged > planar cutters, with an average tangential order of triple-ridged < axe-shaped < planar cutters. When drilling through hard rock, the average penetration depths of planar, axe-shaped, and triple-ridged cutters were 5.57, 6.06, and 3.91 mm, respectively. The average tangential forces were 670.57, 541.76, and 347.89 N, respectively. During the transition from soft to hard rock during drilling, the tangential forces of the planar, axe-shaped, and triple-ridged cutters increased by 8.41%, 3.21%, and 2.64%, respectively. The planar cutter experienced the most significant instantaneous tangential-force change and was more prone to impact damage. Increasing the amplitude of the axial stress waves helps enhance the penetration depth of the drill bit, whereas increasing the frequency of the stress waves can reduce the intensity of fluctuations during drill-bit penetration and increase drill-bit stability. The research results provide insights into optimizing drilling cutters and engineering parameters during rotary percussion drilling.