Wave Peak Research Articles

Measurement and Evaluation of Metal-to-Metal Seals Sealability by Ultrasonic Phased Array

The magnitude and distribution of contact stress on the metal-to-metal seal interface of premium connection has been confirmed as a direct factor of the sealing integrity. In this study, the method of evaluating sealability by measuring contact stress on metal-to-metal seals with the ultrasonic phased array is investigated. A loading system and ultrasonic phased array measurement system of cone-cone contact samples were created. The recommended detection method is focusing -deflection, and the time compensation method is suggested to extract the reflected wave peak of the sealing surface. The experiments show that the reflected wave peak declines with the rise of the axial load, with the big end showing the most noticeable reduction. The shift in the reflected wave peak also reflects the axial movement of the contact interface. The contact stress is calculated according to the reflection coefficient and compared with the simulation results. The distribution trend of contact stress is consistent. The sealing index measurement error is less than 15%, and the measurement error is decreased with the decrease of the sealing surface angle. Then, the nephogram of contact stress distribution on the sealing surface is formed to visualize the contact stress, which takes on great significance in engineering.

Association between children's home-schooling and parental psychological distress during the COVID-19 pandemic in Taiwan: Risk and protective factors in a multilevel approach

The role home-schooling of children in parental mental health during the COVID-19 pandemic in Taiwan remains unknown. This study aimed to assess the association between parental psychological distress and home-schooling in a socio-ecological context during the peak of the first wave of the COVID-19 pandemic in Taiwan. This was a prospective cohort study. In total, 902 parents (father: n=206, mother: n=696) who home-schooled children under 18 years of age were recruited by purposive sampling from 17 cities in Taiwan. Data were collected between 19 July and 30 September 2021 through a survey. Multilevel regression models were used to examine the association between parents' psychological distress and home-schooling considering the characteristics at the person and city levels. Parental psychological distress was positively associated with difficulty in setting up electronic devices and increased disputes between parents and children, and it was negatively associated with time management and increased time spent bonding with their children during home-schooling (Ps<0.05). Parents who had a child with health conditions, lived in an extended family, worked from home, lived during the Level 3 alert level, and lived with a median/sporadic level of the COVID-19 community spread by city also reported greater psychological distress (Ps<0.05). However, parents who had greater household family support reported less psychological distress (P<.05). Clinicians and policy makers must carefully consider parental mental health while home-schooling during the COVID-19 pandemic in a broader socio-ecological context. A focus is advised on the home-schooling experiences of parents and other risk and protective factors for parental psychological distress at the person and city levels, especially for those with children who require medical interventions and have a medical condition.

Combination of current and new electrocardiographic-based criteria: a novel score for the discrimination of left bundle branch capture

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch (LBB) area pacing (LBBAP) has been widely adopted for an increasing number of antibradycardia and CRT procedures worldwide. Two different types of capture have been described during LBBAP: left ventricular septal myocardial capture (LVSP) or direct LBB capture via non-selective (ns)-LBB or selective (s)-LBB pacing (LBBP). Nevertheless, electrocardiographic diagnosis of direct LBB capture remains one of the challenges of modern conduction system pacing. Purpose We hypothesized that the combination of several ECG-based criteria might discriminate better LBBP from LVSP, than each criterion separately. Methods Single-center study involving all consecutive patients who received LBBAP. LBBP was defined according to QRS morphology transition criteria during decremental pacing. Multivariate logistic regression analysis was performed to develop a predictive score for LBBP (The LBBP score), by entering three ECG-based criteria: the previously reported and widely adopted R wave peak time in lead V6 (V6-RWPT) and V6-V1 interpeak interval, and the novel aVL-RWPT, that had been tested before in our sample by the performance of ROC curve analysis. The predictive performance of the regression model was evaluated through the ROC curve and compared to those of the isolated criteria with the De Long test. The regression equation derived from the multivariate model was obtained. To simplify its performance in clinical practice, a heuristic method was used to develop the score: each criterion was weighted according to the result of the Wald test. The construction of the score is depicted in Figure 2. Results A total of 188 patients with intended LBBAP were screened. Successful LBBAP was achieved in 174 (92.5%). 71 patients with confirmed LBB capture by the QRS morphology transition criteria were analysed to develop the predictive score. The optimal cut-off values of V6-RWPT, V6-V1 interpeak interval and aVL-RWPT for the discrimination of LBBP were &amp;lt;83 ms, ≥33 ms and &amp;lt;79 ms, respectively. The multivariate logistic regression model showed that the three analysed ECG-based criteria were independent and not redundant predictors of LBBP. The ROC analysis for the multivariate regression model showed an AUC of 0.980 to differentiate LBB and LVS captures. The probability of LBBP can be calculated by using the calculation formula shown in Figure 1. The ROC curve for the differential diagnosis of LBBP and LVSP with the score showed an AUC of 0.976, with an optimal cut-off value of 3 points (Sensitivity 89.2%, Specificity 100%) for the differentiation of LBB capture. Conclusions The combination of V6-RWPT, V6-V1 interpeak interval and aVL-RWPT into a new score exhibited a good power to discriminate LBBP from LVSP. None of the reported cut-off values of current ECG-based criteria have shown such high relationship between both sensitivity and specificity, so the LBBP score might be an efficient and precise tool to implement in clinical practice.

Validation of left bundle branch pacing criteria: are we really doing it well?

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch (LBB) area pacing (LBBAP) has been widely adopted for an increasing number of antibradycardia and CRT procedures worldwide. Two different types of capture have been described during LBBAP: left ventricular septal myocardial capture (LVSP) or direct LBB capture (LBBP). Nevertheless, electrocardiographic diagnosis of LBBAP remains one of the challenges of modern conduction system pacing because there is a big overlap between both electrocardiographic morphologies. Among the new ECG-based criteria, the R wave peak time in lead V6 (V6-RWPT) and V6-V1 interpeak interval seem to be the most practical ones and have been widely adopted. However, their performance have never been validated in an external population. Purpose We aim to validate the reported criteria V6-RWTP and the V6-V1 interpeak interval in an our population. Methods Single-center study involving all consecutive patients who received LBBAP. LBBP was defined according to the presence of QRS morphology transition criteria during decremental pacing. The performance of binary decision rules was described using sensitivity (SN) and specificity (SP). The performance of V6-RWPT and V6-V1 interpeak interval in discriminating between LBBP and LVSP was assessed using the receiver operating characteristic (ROC) curve. Results A total of 188 patients with intended LBBAP were screened. Successful LBBAP was achieved in 174 (92.5%). Only 71 patients with confirmed LBBP by the QRS morphology transition criteria were included to analyse the performance of V6-RWPT and V6-V1 interpeak interval. The V6-RWPT was 75.7±9.6 ms for LBBP tracings and 94.4±10.1 ms for LVS tracings (p&amp;lt;0.001), and V6-V1 interpeak interval was 41.9±12.1 ms for LBB capture and 25.6±8.7 ms for LVS capture (p&amp;lt;0.001). The average difference in V6-RWPT for the transition from LBBP to LVSP was 16.5±5.2 ms. The ROC curves for the differential diagnosis of LBBP and LVS capture (Figure 1, which compares them with those from the original articles) showed a diagnostically optimal V6-RWPT value for the differentiation of LBBP and LVS capture of 83 ms (SN of 80.3% and SP of 91.1%). A SP of 100% for the diagnosis of LBBP was achieved with a cut-off value of 79.5 ms (SN 69.0%). For the V6-V1 interpeak interval, the diagnostically optimal value for the differentiation of LBBP was 33.5 ms (SN of 77.1% and SP of 84.6%). A SP of 100% for the diagnosis of LBBP was obtained with a cut-off value &amp;gt;44 ms (SN 37.1%) (Figure 2). Conclusions Our study comprises an external validation of the proposed ECG-based criteria for LBB capture. We found a nearly absolute concordance with the originally reported V6-RWPT and V6-V1 interpeak interval cut-off values. Only the V6-RWPT cut-off value with 100% specificity differed from the initially reported in the general cohort. Thus, the V6-RWPT and V6-V1 interpeak interval criteria seem to be consistent and emerge as practical and easily reproducible surrogates of the QRS transition criteria.

COVID-19 perseverative cognition and depressive symptoms in Hong Kong: The moderating role of resilience, loneliness and coping strategies

BackgroundThe COVID-19 pandemic significantly increased depression prevalence in general population. However, the relationship between persistent dysfunctional thinking associated with COVID-19 (perseverative-cognition) and depression, and its potential moderators are understudied. We aimed to examine the association between COVID-19 perseverative-cognition and depression, and the moderating effect of potential risk and protective factors on this association in general public during the peak of fifth COVID-19 wave in Hong Kong. MethodsThis survey recruited 14,269 community-dwelling adults between March 15–April 3, 2022 to investigate association between COVID-19 perseverative-cognition and depression, and the moderating effect of resilience, loneliness and three coping strategies (including emotion-focused, problem-focused and avoidant coping) on this association, using hierarchical regression models and simple slope analyses. COVID-19 perseverative cognition was assessed by the Obsession with COVID-19 Scale (OCS) and depressive symptoms were measured by the Patient Health Questionnaire-9 (PHQ-9). ResultsPerseverative-cognition was positively associated with depression severity. Resilience, loneliness and three coping strategies moderated the association between perseverative-cognition and depression. Specifically, greater resilience and emotion-focused coping ameliorated the association between perseverative-cognition and depression, while higher levels of loneliness, avoidant and problem-focused coping accentuated such association. LimitationsCross-sectional design precluded establishing causality among variables. ConclusionThis study affirms that COVID-19 perseverative-cognition is significantly related to depression. Our findings indicate the potential critical role of enhanced personal resilience and social support, and adoption of emotion-focused coping in mitigating negative effect of COVID-19 related maladaptive thinking on depression severity, thereby facilitating development of targeted strategies to reduce psychological distress amidst the prolonged pandemic.

Flexible microfluidic triboelectric sensor for gesture recognition and information encoding

Flexible triboelectric sensor has a broad application prospects in self-powered human-machine interface. However, due to the complexity of real environment, the output signal is easily disturbed, thus resulting in low reliability. Here, a flexible microfluidic triboelectric sensor (FMTS) was proposed by counting the number of wave peaks in output waveform. With a high transmittance of 82%, the FMTS shows bendable, twistable and conformable characteristics so that can be operated attached to skin. Based on triboelectrification and electrostatic induction between liquid stream, microchannel and interdigital electrodes, it enables to generate quantifiable voltage wave peaks. The FMTS has a maximum sensitivity of 0.418 kPa−1 and a wide detection range from 2.38 to 58.12 kPa with the microchannel width of 500 µm. For demonstration, a FMTS is attached to the finger, and the number of peaks is used to determine the angle of finger bending with a resolution of 10°. The machine learning approach is employed to achieve accurate recognition of five gestures with an accuracy of 99.2%. The information can also be defined by using waveforms generated by different combinations of movements. An encoding system that recognizes eight types of information with an accuracy of up to 98.8% is finally demonstrated.

Assessing the impact of wave model calibration in the uncertainty of wave energy estimation

The accuracy of estimated sea conditions, specifically wave height and peak/average wave periods, affects the estimation of electrical energy production from wave energy converters. This study investigates the uncertainty in wave energy harvesting estimated by the SWAN wave model and determines possible improvements by adjusting the model's tunable parameters. Three different wave energy converters (OEBuoy, WaveBob, and Pontoon) and ten different locations along the Atlantic coast of the Iberian Peninsula are used in the study. The SWAN model is calibrated using the ST6 term package based on both wave height and peak period wave parameters. Different wave hindcast data produced by different model settings are used to estimate the wave energy produced by the wave energy converters at ten buoy locations and compared to wave energy produced estimated based on wave observations. The study finds that the physical settings of the SWAN model have a considerable influence on the uncertainty in the estimation of the power output produced by the device. The best-fitting calibrated model improved the mean energy output value of all locations compared to the SWAN default settings. The study concludes that adjusting the SWAN model parameters can improve the accuracy of the estimation of the energy output.

Brazil's Amazon Oxygen Crisis: How Lives and Health Were Sacrificed During the Peak of COVID-19 to Promote an Agenda with Long-Term Consequences for the Environment, Indigenous Peoples, and Health.

In January 2021, oxygen supplies in the Amazon region's largest city were allowed to run out at the peak of the second wave of the COVID-19 epidemic, shocking the world as hospital patients expired for lack of this basic medical resource in Manaus, which during the first COVID-19 wave had become the world's first city to bury its dead in mass graves. Brazil's authorities used this tragedy to further a political agenda that implies enormous environmental and human-rights consequences. Transport of oxygen was used to promote building a road that, together with its planned side roads, would give deforesters access to much of what remains of Brazil's Amazon Forest. Here, we demonstrate that the logistical strategy adopted by the Jair Bolsonaro administration's Ministries of Health and Infrastructure to bring oxygen to Manaus was the worst possible choice, and the foreseeable delay in the arrival of oxygen cost hundreds of lives. Rather than sending trucks to carry oxygen on the nearly impassible Highway BR-319 during the rainy season, the most appropriate transport option was barges on the Madeira River. As oxygen supplies dwindled in Manaus, the families of wealthier COVID-19 victims scrambled to buy the few remaining cylinders at prices out of reach for those in poorer (and often ethnically distinct) economic strata. Ethnic health disparities are aggravated by both the direct consequences of the oxygen crisis and, on the longer term, by the consequences of the highway project that political use of the crisis materially advanced.

Heterogeneity of echocardiographic variables in systemic lupus erythematosus among clinical subgroups according to non-cardiac organ involvement

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease. Cardiac involvement is rare but plays an important prognostic role. The degree of cardiac involvement according to SLE subsets defined by non-cardiac manifestations is unknown. The objective of this study was to identify differences in TTE parameters associated with different SLE subgroups. One hundred and eighty-one patients fulfilling the ACR/EULAR 2019 classification criteria for SLE and had a TTE were included in this cross-sectional study. We defined four subsets of SLE based on the predominant clinical manifestations. A multivariate multinomial regression analysis was performed to determine whether TTE parameters differ between the subsets. The first subset (n = 37) of patients showed features of mixed connective tissue disease (MCTD); the second subset (n = 76) had primarily cutaneous involvement; the third subset (n = 18) exhibited serositis and the last subset (n = 50) had severe disease with significant organ involvement, including renal involvement. Forty TTE parameters were assessed in each patient. Using a multivariate multinomial regression analysis, 3 parameters differed between groups: early diastolic tricuspid annular velocity (RV-E′, P < 0.0001), RV-S′ (RV-pulse DTI systolic peak wave, P = 0.0031), and RV end-diastole diameter (P = 0.0419). The degree of RV dysfunction was lowest in patients with primarily cutaneous involvement. Four distinct clinical subsets based on clinical manifestations differed in terms of TTE parameters of right heart function and diastolic dysfunction. This could help to tailor the cardiac follow-up required by the different clinical subsets of SLE.

Full-surface defect detection of navel orange based on hyperspectral online sorting technology.

The whole-surface hyperspectral image acquisition of navel orange is particularly important for surface defect detection and quality classification. Because the light intensity at the edge of the navel orange is lower than that in the middle, the defects on the surface of the navel orange cannot be effectively identified. In this paper, a hyperspectral online sorting device for the whole-surface defects of navel orange is proposed. First of all, the image data of navel orange is collected by online detection sorting equipment and the spectral image of the characteristic wave peak of 1655.72nm was extracted. Then, the light intensity at the edge of the navel orange is enhanced by nonuniformity correction based on quadratic curve fitting, and the light intensity correction of the navel orange is realized. Finally, the corrected image is segmented by the threshold to obtain surface defects, and the number of surface defect pixels is improved effectively compared with that before light intensity correction. Ultimately, the online sorting test is carried out, and the detection accuracy is 100%. This indicates that this method effectively improves the sensitivity of defect detection. At the same time, the dimensionality reduction of hyperspectral data is also carried out, which is conducive to improving the efficiency of online detection.

Effect of Tide Level Change on Typhoon Waves in the Taiwan Strait and Its Adjacent Waters

In recent years, most research on typhoons in the Taiwan Strait and its adjacent waters has focused on simulating typhoon waves under the influence of wind fields. In order to study the influence of tidal level changes on typhoon waves, a numerical model was established in the Taiwan Strait based on the third-generation ocean wave model SWAN. The simulation results of the tide level during the corresponding typhoon landing time were incorporated into the model to optimize its performance. Subsequently, the wave height of the typhoon landing at the lowest tide level was compared with that at the highest tide level. This comparison serves as a reference and warning for ocean engineering, highlighting the hazards of the typhoon landing at high tide. The simulation results were verified and analyzed using the measured data of significant wave heights and wind speeds when typhoons Mekkhala (2006) and Maria (0607) approached. The results show that after optimization, the relative error of the significant wave peak is reduced. Furthermore, there has been a decrease in the maximum wind speed, bringing it closer to the measured value. These improvements signify enhanced model accuracy. The tide level has a great influence on the typhoon wave, and the tide level height at the time of the typhoon landing is positively correlated with the significant wave height of the waves generated by the typhoon. When the typhoon’s landing time coincides with the high tide level, the resulting waves are significantly higher, reaching up to 0.71 m. This has a substantial impact on the safety of marine structures, particularly breakwaters.

Effect of Al/O ratio on underwater explosion energy characteristics of CL‐20‐based aluminized explosives

AbstractTo study the underwater explosion energy characteristics of CL‐20‐based aluminized explosives with different Al/O ratio, underwater detonation parameters of explosives, including the shock wave peak pressure, the decay time, the bubble pulsation period, the shock wave energy and the bubble energy at 1 m, were measured by a series of underwater explosion experiments. The calculation model of CL‐20‐based aluminized explosive in the pool was established by using Ansys LS‐DYNA software and was calculated the shock wave energy and bubble pulsation period. The results showed that Al/O ratio significantly changed the energy output structure of CL‐20‐based aluminized explosives. With increasing Al/O ratio, the proportion of shock wave energy in the total energy decreased, while the proportion of bubble energy increased. When Al/O ratio was 0.35, the shock wave peak pressure and shock wave energy of the explosive were the largest, and when the ratio was 0.6, the bubble period and total energy reach their maximum; when the ratio was 0.94, the bubble energy and the bubble pulsation reached the maximum. The experimental values are in good agreement with the simulation results, and the model can be used to estimate the underwater detonation parameters of CL‐20‐based aluminized explosives with different Al/O ratio.

Home-based care programme (HBCP) for patients with COVID -19: Boon or burden during pandemic management?

Introduction and Aim: India experienced the peak of the second wave of COVID-19 during April to June 2021. Massive surge of cases resulting in shortage of beds and oxygen, home care was recommended as a strategy for management of asymptomatic/mild COVID -19 cases. The present study was undertaken to perform home visits and monitor COVID 19 patients who are a part of home-based care programme (HBCP) in Puttur taluk of Dakshina Kannada district, identification and immediate referral of patients with red flag signs/ symptoms and to identify barriers/challenges faced by health care staff in implementing the programme. Methodology: The present study was a cross-sectional study with universal sampling. It was carried out as part of a district programme for management of home isolation COVID-19 patients. The team visited the houses of COVID-19 patients and evaluated them. Results: A total of 112 COVID-19 patients were in home isolation during the study period in Puttur Taluk. Hypertension (29.5%) was the most common co-morbidity and nearly two-fifths (41.1%) of the study participants had one or more comorbidities. Almost two-third (63%) of the patients with comorbidities were symptomatic compared to only 29.4% of patients without any comorbidities. Of the six patients who had saturation of less than 95% five were more than 60 years of age, only one had received vaccination against COVID-19 and all had comorbidities. The HBCP had to face several challenges as the team members could not be in full PPE because of long distances between the houses and hard to reach areas. Conclusion: Overall, it is a helpful initiative for patients as the health services were provided at the doorstep during the time of restriction of movement. This can be an important tool in managing not only COVID pandemic but also future outbreaks that may follow.

Pediatric Dilemma of the Third Wave Pandemic of COVID-19 in A Tertiary Care Hospital for Children

Background: In February 2020, a novel coronavirus caused a pandemic affecting children and adults with different presentations and outcomes. Objectives: The current study aimed to provide descriptive values regarding the clinical and laboratory profiles of children suspected of coronavirus disease 2019 (COVID-19). This purpose was achieved by studying all presentations, whether clinical or laboratory, typical or atypical, of suspected COVID-19-affected children at the peak of the third wave in a large tertiary hospital. Methods: This cross-sectional study enrolled 404 children with suspected COVID-19 who were tested in the Emergency Room of Abu El-Reesh Japanese Hospital, Cairo, Egypt, during the study period, which was from March 2021 to the end of October 2021. According to age, the patients were divided into four groups, including those under 2 years, the early childhood group (2 - 6 years), the late childhood group (6 - 12 years), and those over 12 years. The enrolled cases met the diagnostic criteria for COVID-19 according to the Egyptian Ministry of Health protocol. Results: In this study, 58 out of 404 tested children were positive for COVID-19 (14%), with a higher male predominance (n = 230/404, or 56.9% of the study group). The median age of the study participants was 1.6 years. Out of all presentations, the non-respiratory ones predominated and had the upper hand. It represented 62.9% (254/404) of the total presentations of the enrolled children. Among the non-respiratory manifestations, gastrointestinal ones were predominant (n = 63). Thrombocytopenia, leucopenia, and pancytopenia were significantly higher in children with non-respiratory manifestations than in those with respiratory manifestations. Conclusions: Children might have atypical manifestations of COVID-19 infections. The non-respiratory system could predominate in children. Thrombocytopenia could be a laboratory marker for COVID-19 infection, especially in those with predominant non-respiratory manifestations. Respiratory manifestations in children could be a guide for other systemic affections.

Short-term analysis of extreme wave-induced forces on the connections of a floating breakwater

In the design of floating breakwaters, assessment of the extreme wave-induced loads on the connections, their weakest element, is required to ensure structure survival. This case study provides guidelines for estimating the extreme wave-induced forces on the connections of a floating breakwater. A Boundary Element Method (BEM) solver was applied to obtain the time-domain response of an array of five pontoons anchored to the sea bottom with elastic mooring lines. The hydrodynamic behaviour of the structure was assessed for short-duration sea states with different wave peak periods and oblique wave directions. Two peak selection criteria were applied to obtain force distributions, and several different probability density functions (PDF) were fitted to the resulting data. The extreme wave-induced forces on every connection and sea state were estimated for two different exceedance levels during a typical 3-h sea state. Based on the results, combination of the Peaks Over Threshold (POT) method and generalized Pareto distribution results is proposed for estimating the wave-induced design forces on the connections of floating pontoon breakwaters.

Residents’ citizenship behavior between collectivism and individualism: the roles of COVID-19 recurrence risk and length of residency

COVID-19 has revealed that locals may perceive tourists as possible infection vectors. In addition, little research has been conducted on residents’ perceived risks from Golden Week holidayers. Our study examines the relationship between individual cultural orientation and risk perception regarding COVID-19 recurrence (RCOVID-19 recurrence), specifically seeking to explain residents’ citizenship behaviors. We collected data on Jeju, South Korea, right after the peak of the first wave of COVID-19 in 2020 when Golden Week holidayers visited Jeju. Our findings identified the mediation effect of RCOVID-19 resulting from the significant relationships between individualism or collectivism, RCOVID-19 recurrence, and citizenship behavior, except for the path from horizontal collectivism to citizenship behavior. In addition, the moderation role of the length of residency is identified. We conclude our paper with a discussion on theoretical and practical implications.

Freak wave events in 2005–2021: statistics and analysis of favourable wave and wind conditions

Abstract. Freak or rogue waves are unexpectedly and abnormally large waves in seas and oceans, which can cause loss of human lives and damage to ships, oil platforms, and coastal structures. Evidence of such waves is widely spread around the globe. The present paper is devoted to analysis of the unified collection of freak wave events from different chronicles and catalogues from 2005 to 2021. The considered rogue waves are not measured in situ data, but their descriptions, which have been found in mass media sources and scientific articles, are the data used. All of them resulted in damage to ships or coastal/offshore structures and/or human losses. The collection accounts for 429 events. First, the analysis based on their characteristics taken from the descriptions of the events (including locations, water depth, damages) is carried out. Second, the analysis of wave parameters taken from the climate reanalysis ERA5 is performed. Thus, the most probable background wave parameters at the time of the freak event (including wind speed, gusts, significant wave height, maximum wave height, peak wave period, skewness, excess kurtosis, Benjamin–Feir instability (BFI), and wave spectral directional width) for each freak wave event are determined.

PE-454609-1 MYOCARDIAL WORK IN VENTRICULAR PREEXCITATION

Ventricular preexcitation alters the electromechanical activation sequence and may induce left ventricular (LV) contractile discoordination and pathologic remodelling in selected cases. To evaluate LV myocardial work before and after accessory pathway (AP) ablation in patients with WPW preexcitation and to compare them to normal controls. Mechanical activation mapping and myocardial work calculation was performed in 11 pediatric patients with the WPW syndrome/pattern and left sided or paraseptal APs undergoing catheter ablation (successful in 10/11) and 8 healthy age-matched controls using speckle tracking echocardiography and the GE ECHOPAC version 204.57.0.745 software with the integrated AFI module. An 18-segmental echocardiographic LV model was used. Global LV myocardial work efficiency (GWE) was calculated as the ratio of global constructive work to the sum of global constructive and global wasted work (GWW). The time from delta wave onset to R wave peak in lead V6 (delta to R) was used to quantify the degree of preexcitation. Before ablation GWW was higher (164 vs 102 mmHg%, P=0.015) and GWE lower (median 91 vs 94%, P=0.010) in patients vs controls. After successful ablation GWW decreased from 164 to 93 mmHg% (P=0.006) and GWE increased from 91.1 to 94.0 % (P=0.006). GWE tended to correlate negatively with the delta to R interval (R=0.59, P=0.056). Before ablation, segmental WE increased with distance from ventricular AP insertion from median 69.5 % at AP location to 98.0 % in distant segments (P<0.001). After ablation, WE was equally distributed among LV segments (Figure). Mechanical activation mapping localized APs with a median (IQR) segmental distance of 0 (0-1) segments from the EP mapped location. Ventricular preexcitation induces significant LV myocardial work inefficiency in segments adjacent to AP which correlates with the degree of preexcitation and is normalized after ablation. The amount of wasted work in asymptomatic preexcitation may be considered when assessing the potential for pathologic LV remodelling or discussing the indication for prophylactic ablation. Mechanical activation mapping may be used to localize manifest APs.

Increased detection of Echovirus 6-associated meningitis in patients hospitalized during the COVID-19 pandemic, Israel 2021-2022.

Outbreaks of enteroviral meningitis occur periodically and may lead to hospitalization and severe disease. To analyze and describe the meningitis outbreak in patients hospitalized in Israel in 2021-2022, during the COVID-19 pandemic. In December 2021, before the emergence of the SARS-CoV-2 omicron variant, an off-season increase in enterovirus (EV) infections was observed among patients hospitalized with meningitis. In January 2022, enterovirus cases decreased by 66% in parallel with the peak of the Omicron wave, and then increased rapidly by 78% in March (compared with February) after a decline in Omicron cases. Sequencing of the enterovirus-positive samples showed a dominance of echovirus 6 (E-6) (29%) before and after the Omicron wave. Phylogenetic analysis found that all 29 samples were very similar and all clustered in the E-6 C1 subtype. The main E-6 symptoms observed were fever and headache, along with vomiting and neck stiffness. The median patient age was 25 years, with a broad range (0-60 years). An upsurge in enterovirus cases was observed after the decline of the SARS-CoV-2 omicron wave. The dominant subtype was E-6, which was present prior to the emergence of the omicron variant, but increased rapidly only after the omicron wave decline. We hypothesize that the omicron wave delayed the rise in E-6-associated meningitis.

Global Distribution of Discrete and Continuous Spectrum Equatorial Magnetosonic Waves Observed by the Van Allen Probe‐A

AbstractMagnetosonic (MS) waves can either be discrete or continuous in the time‐frequency spectrogram. Through the observation from Van Allen Probe‐A spacecraft, the global distribution of discrete and continuous spectrum MS waves in the region L ∼ 3–6 is determined. According to our research, the continuous spectrum MS waves are greater in amplitude than discrete spectrum MS waves. Also, the impact of changes in geomagnetic activity on continuous spectrum MS waves is much more significant than discrete spectrum MS waves. Besides, it is also demonstrated that the strong discrete spectrum MS waves have a peak wave amplitude of ∼60 pT and an occurrence rate of ∼50% at the noon sector outside the plasmapause. In comparison, the strong continuous spectrum MS waves have a peak wave amplitude of ∼300 pT and an occurrence rate of ∼60% at the postnoon sector inside the plasmapause.