Real-world assessment of multipolar and point-by-point mapping for premature ventricular contraction ablation.

AIMS: We aimed to assess the acute and midterm efficacy of premature ventricular contraction (PVC) ablation guided by multielectrode and point-by-point (PbP) mapping. METHODS AND RESULTS: This is a retrospective, international multicentre study of consecutive patients referred for PVC ablation in 10 hospital centres from January 2017 to December 2021. Based on the mapping approach, two cohorts were identified: the 'Multipolar group', where a dedicated high-density mapping catheter was employed, and the 'PbP group', where mapping was performed with the ablation catheter. Procedural endpoints, safety, and acute (procedural) and midterm efficacies were assessed. Of the 698 patients included in this study, 592 received activation mapping [46% males, median age of 55 (41-65) years]-248 patients in the Multipolar group and 344 patients in the PbP group. A higher number of activation points [432 (217-843) vs. 95 (42-185), P < 0.001], reduced mapping time (40 ± 38 vs. 61 ± 50 min, P < 0.001), and shorter procedure time (124 ± 60 vs. 143 ± 63 min, P < 0.001) were reported in the Multipolar group. Both groups had high acute success rates (84.7% with Multipolar mapping vs. 81.3% with PbP mapping, P = 0.63), as well as midterm efficacy (83.4% vs. 77.4%, P = 0.08), with no significant differences in the risk of adverse events (6.0% vs. 3.5%, P = 0.24). However, for left-sided PVC ablation specifically, there was a higher midterm efficacy in the Multipolar group (80.7% vs. 69.5%, P = 0.04), with multipolar mapping being an independent predictor of success [adjusted OR = 2.231 (95% CI, 1.476-5.108), P = 0.02]. CONCLUSION: The acute and midterm efficacies of PVC ablation are high with both multipolar and PbP mapping, although the former allows for quicker procedures and may potentially improve the outcomes of left-sided PVC ablation.

Dynamics of dimorphic workers of Constrictotermes cyphergaster (Blattodea: Termitidae) during nest repair.

Termite nest repairs are considered a defensive conduct as they reduce the colony's exposure to the external environment. Repair activities are carried out by worker castes that can be polymorphic, representing a relationship between polymorphism and divisions of functions that can enhance task completion. Repairs are influenced by the extent of damage, nest volume, and the population dynamics of the building species, which regulate the recruitment of individuals for this activity. Our objective was to verify the performances (recruitment for repair) of dimorphic workers of Constrictotermes cyphergaster (Silvestri, 1901) during the damage repair activities performed on the external walls of termite nests of different sizes. We found a significant difference in the presence of dimorphic workers that performed repairs, with greater recruitment of the small morphotype, and observed an alternation of morphotypes between initial and final repair activities, with no influence of morphotype on the replacement pattern. Our results also showed that the total number of recruited workers decreased with increasing nest volume. These results help to better understand the social organization of a Nasutitermitinae termite species and the strategies adopted to protect its colonies.

Response rate in cardiac resynchronization therapy patients implanted with a left ventricular quadripolar lead and the MultiPoint™ pacing feature early activated. QUARTO III.

BACKGROUND: Although cardiac resynchronization therapy (CRT) is beneficial in most heart failure patients, up to 40% do not respond to CRT. It has been suggested that multipoint left ventricle pacing (MPP) would increase the response rate. AIM: To assess the CRT response rate at 6 months in patients implanted with a CRT device with the MPP feature activated early after the implant. METHODS: This was a multicentre, prospective, open-label and non-randomized study. The primary endpoint was response to biventricular pacing defined as >15% relative reduction in left ventricular end-systolic volume (LVESV) comparing echocardiography measurements performed at baseline and 6 months by a core laboratory. Among secondary endpoints the combined endpoint of mortality or all-cause hospitalizations was evaluated. Primary study endpoint and clinical outcomes were compared to a Quarto II control cohort. RESULTS: Totally, 105 patients were included. The response rate was 64.6% (97.5% lower confidence bound 53%). Mean relative reduction in LVESV was 25.3%, and mean absolute increase in LVEF was 9.4%. The subjects with device programmed using anatomical approach showed a trend towards higher responder rate than those using the electrical approach (72% vs. 61.1%, p = 0.32). Finally, the combined incidence of mortality and or all-cause hospitalizations at 6 month was 12.4%. CONCLUSIONS: Early activation of MPP was not associated to an advantage increasing echocardiography responders to CRT at 6 months of follow-up. Nevertheless, patients programmed using widest pacing cathodes had a numerically higher responder rate. Finally, early activation of MPP was associated to a low incidence of clinical endpoints at 6 months of follow-up.

Nonequilibrium Thermodynamics of the Majority Vote Model.

The majority vote model is one of the simplest opinion systems yielding distinct phase transitions and has garnered significant interest in recent years. This model, as well as many other stochastic lattice models, are formulated in terms of stochastic rules with no connection to thermodynamics, precluding the achievement of quantities such as power and heat, as well as their behaviors at phase transition regimes. Here, we circumvent this limitation by introducing the idea of a distinct and well-defined thermal reservoir associated to each local configuration. Thermodynamic properties are derived for a generic majority vote model, irrespective of its neighborhood and lattice topology. The behavior of energy/heat fluxes at phase transitions, whether continuous or discontinuous, in regular and complex topologies, is investigated in detail. Unraveling the contribution of each local configuration explains the nature of the phase diagram and reveals how dissipation arises from the dynamics.

Toxoplasma gondii Infection Decreases Intestinal 5-Lipoxygenase Expression, while Exogenous LTB4 Controls Parasite Growth.

5-Lipoxygenase (5-LO) is an enzyme required for the production of leukotrienes and lipoxins and interferes with parasitic infections. In vitro, Toxoplasma gondii inhibits leukotriene B4 (LTB4) production, and mice deficient in 5-LO are highly susceptible to infection. The aim of this study was to investigate the effects of the pharmacological inhibition of the 5-LO pathway and exogenous LTB4 supplementation during experimental toxoplasmosis. For this purpose, susceptible C57BL/6 mice were orally infected with T. gondii and treated with LTB4 or MK886 (a selective leukotriene inhibitor through inhibition of 5-LO-activating protein [FLAP]). The parasitism, histology, and immunological parameters were analyzed. The infection decreased 5-LO expression in the small intestine, and treatment with MK886 reinforced this reduction during infection; in addition, MK886-treated infected mice presented higher intestinal parasitism, which was associated with lower local interleukin-6 (IL-6), interferon gamma (IFN-γ), and tumor necrosis factor (TNF) production. In contrast, treatment with LTB4 controlled parasite replication in the small intestine, liver, and lung and decreased pulmonary pathology. Interestingly, treatment with LTB4 also preserved the number of Paneth cells and increased α-defensins expression and IgA levels in the small intestine of infected mice. Altogether, these data demonstrated that T. gondii infection is associated with a decrease in 5-LO expression, and on the other hand, treatment with the 5-LO pathway product LTB4 resulted in better control of parasite growth in the organs, adding to the knowledge about the pathogenesis of T. gondii infection.

Cardiac pacing in severe recurrent reflex syncope and tilt-induced asystole.

AIM: The benefit of cardiac pacing in patients with severe recurrent reflex syncope and asystole induced by tilt testing has not been established. The usefulness of tilt-table test to select candidates for cardiac pacing is controversial. METHODS AND RESULTS: We randomly assigned patients aged 40 years or older who had at least two episodes of unpredictable severe reflex syncope during the last year and a tilt-induced syncope with an asystolic pause longer than 3 s, to receive either an active (pacing ON; 63 patients) or an inactive (pacing OFF; 64 patients) dual-chamber pacemaker with closed loop stimulation (CLS). The primary endpoint was the time to first recurrence of syncope. Patients and independent outcome assessors were blinded to the assigned treatment. After a median follow-up of 11.2 months, syncope occurred in significantly fewer patients in the pacing group than in the control group [10 (16%) vs. 34 (53%); hazard ratio, 0.23; P = 0.00005]. The estimated syncope recurrence rate at 1 year was 19% (pacing) and 53% (control) and at 2 years, 22% (pacing) and 68% (control). A combined endpoint of syncope or presyncope occurred in significantly fewer patients in the pacing group [23 (37%) vs. 40 (63%); hazard ratio, 0.44; P = 0.002]. Minor device-related adverse events were reported in five patients (4%). CONCLUSION: In patients aged 40 years or older, affected by severe recurrent reflex syncope and tilt-induced asystole, dual-chamber pacemaker with CLS is highly effective in reducing the recurrences of syncope. Our findings support the inclusion of tilt testing as a useful method to select candidates for cardiac pacing. STUDY REGISTRATION: ClinicalTrials.gov identifier NCT02324920, Eudamed number CIV-05-013546.

The imbalance of TNF and IL-6 levels and FOXP3 expression at the maternal-fetal interface is involved in adverse pregnancy outcomes in a susceptible murine model of congenital toxoplasmosis.

Vertical transmission of Toxoplasma gondii leads to adverse pregnancy outcomes depending on the time at which the infection occurs and the immunological state of the mother. C57BL/6 and BALB/c mice have been described as susceptible and resistant mouse lineages to congenital T. gondii infection, respectively. This study aimed to elucidate the systemic and local cytokine profile of pregnant mice infected with T. gondii and whether the expression of the transcription factor FOXP3, related to T regulatory cells, is associated with the resistance/susceptibility of these lineages of mice in the context of experimental congenital toxoplasmosis. For this purpose, C57BL/6 and BALB/c females were orally infected with the T. gondii ME-49 strain on the day of vaginal plug detection or day 14 of gestation, examined 7 or 5 days later, respectively, as models of early and late pregnancy. Cytokine levels were measured systemically and in the uterus/placenta. Additionally, the uterus/placenta were evaluated macroscopically for resorption rates and histologically for parasite and FOXP3 immunostaining. The FOXP3 protein expression was also evaluated by western blotting assay. It was found that, during early pregnancy, the infection leads to high IFN-γ, TNF and IL-6 levels systemically, with the TNF levels being higher in C57BL/6 mice. At the maternal-fetal interface, the infection induced high levels of IFN-γ in both mouse lineages; however, higher levels were observed in BALB/c, while high TNF and IL-6 levels were found in C57BL/6, but not in BALB/c mice. In contrast, in late gestation, T. gondii interfered less strongly with the cytokine profile. In early pregnancy, a reduction of FOXP3 expression at the maternal-fetal interface of infected mice was also observed, and the reduction was larger in C57BL/6 compared with BALB/c mice. Additionally, the parasite was seldom found in the uterus/placenta. Thus, the worse pregnancy outcomes observed in C57BL/6 mice were associated with higher TNF systemically, and TNF and IL-6 at the maternal-fetal interface, with lower FOXP3 expression.

Effect of treatment with carvacrol and aerobic training on cardiovascular function in spontaneously hypertensive rats.

NEW FINDINGS: What is the central question of this study? Can two non-drug therapies, carvacrol and aerobic physical training, together have additive effects on the reduction of cardiovascular risks and control of arterial hypertension? What is the main finding and its importance? The oral use of carvacrol (20 mg/kg/day) can control sustained hypertension in spontaneously hypertensive rats, and when this use is associated with aerobic physical training, there is a more pronounced effect on the reduction of blood pressure values, making these therapies an adjunct option in the drug treatment of hypertension. ABSTRACT: Systemic arterial hypertension is considered the foremost cardiovascular risk factor, and it is important to examine different therapies that help prevent and treat it, especially when associated with other cardiovascular risk factors. In this context, it is known that both carvacrol and aerobic physical training benefit the cardiovascular system. This study investigated the effects of treatment with carvacrol combined with aerobic exercise on hypertensive rats with cardiovascular risk parameters. We used an experimental design with six groups: normotensive control (Wistar rats); hypertensive control (spontaneously hypertensive rats, SHR); positive control rats treated with amlodipine (Aml-20 mg); rats treated with carvacrol (Carv-20 mg); rats trained with exercise (Exer); and rats treated with carvacrol and exercise (ExerCarv). The treatment lasted for 4 weeks, monitoring heart rate and systolic blood pressure (SBP). At the end of the treatment, vascular reactivity tests were performed in addition to biochemical measurements of urea, creatinine, aspartate aminotransferase, alanine aminotransferase, triglycerides, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, atherogenic indexes, relative heart weight and histopathological analysis of cardiac perivascular tissue. Significant reductions in SBP were observed after the training period, with the ExerCarv group showing a greater magnitude of reduction (∆SBP = 88 ± 10.0 mmHg, 42%). This group also experienced reductions in atherogenic indices and improvement in all analysed lipid parameters, with no differences observed in the Exer group. The findings indicated that the interaction between aerobic exercise and carvacrol offers a greater BP reduction. Exercise is particularly effective for controlling biochemical parameters of cardiovascular risk, regardless of carvacrol use.

EHRA expert consensus statement and practical guide on optimal implantation technique for conventional pacemakers and implantable cardioverter-defibrillators: endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), and the Latin-American Heart Rhythm Society (LAHRS).

With the global increase in device implantations, there is a growing need to train physicians to implant pacemakers and implantable cardioverter-defibrillators. Although there are international recommendations for device indications and programming, there is no consensus to date regarding implantation technique. This document is founded on a systematic literature search and review, and on consensus from an international task force. It aims to fill the gap by setting standards for device implantation.

Quality indicators for the care and outcomes of adults with atrial fibrillation.

AIMS: To develop quality indicators (QIs) that may be used to evaluate the quality of care and outcomes for adults with atrial fibrillation (AF). METHODS AND RESULTS: We followed the ESC methodology for QI development. This methodology involved (i) the identification of the domains of AF care for the diagnosis and management of AF (by a group of experts including members of the ESC Clinical Practice Guidelines Task Force for AF); (ii) the construction of candidate QIs (including a systematic review of the literature); and (iii) the selection of the final set of QIs (using a modified Delphi method). Six domains of care for the diagnosis and management of AF were identified: (i) Patient assessment (baseline and follow-up), (ii) Anticoagulation therapy, (iii) Rate control strategy, (iv) Rhythm control strategy, (v) Risk factor management, and (vi) Outcomes measures, including patient-reported outcome measures (PROMs). In total, 17 main and 17 secondary QIs, which covered all six domains of care for the diagnosis and management of AF, were selected. The outcome domain included measures on the consequences and treatment of AF, as well as PROMs. CONCLUSION: This document defines six domains of AF care (patient assessment, anticoagulation, rate control, rhythm control, risk factor management, and outcomes), and provides 17 main and 17 secondary QIs for the diagnosis and management of AF. It is anticipated that implementation of these QIs will improve the quality of AF care.

Prognostic effect and modulation of cardiac sympathetic function in heart failure patients treated with cardiac resynchronization therapy.

BACKGROUND: Cardiac autonomic dysfunction as assessed by 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy is associated with poor prognosis in heart failure (HF) patients. Although cardiac resynchronization therapy (CRT) has emerged as an effective therapy in improving outcomes on HF patients, its effect on cardiac sympathetic nervous function is still not fully understood. We aimed to study the value of pre-implantation 123I-mIBG late heart-to-mediastinum ratio (HMR) as a predictor of response and outcomes after CRT and to correlate modification in this parameter with CRT response and functional improvement. METHODS AND RESULTS: BETTER-HF (Benefit of exercise training therapy and cardiac resynchronization in HF patients) is a prospective randomized clinical trial including HF patients submitted CRT (mean LVEF 24 ± 8%, 74% NYHA class ≥ III) who underwent a clinical, echocardiographic, and scintigraphic assessment before and 6 months after CRT. One-hundred and twenty-one patients were included. Echocardiographic response was observed in 54% and composite outcome of cardiac mortality, cardiac transplant or heart failure hospitalization in 24% of patients. Baseline late HMR was an independent predictor of CRT response (regression coefficient 2.906, 95% CI 0.293-3.903, P .029) and outcomes (HR 0.066 95% CI 0.005-0.880, P .040). At follow-up, 123I-mIBG imaging showed positive changes in cardiac sympathetic nerve activity only in responders to CRT (1.36 ± 0.14 prior vs. 1.42 ± 0.16 after CRT, P .039). There was a significant correlation between improvement in late HMR and improvement in peak oxygen consumption (r 0.547, P < .001). CONCLUSION: In our study, baseline cardiac denervation predicted response and clinical outcomes after CRT implantation. Cardiac sympathetic function was improved only in patients who responded to CRT and these positive changes were correlated with improvement in functional capacity.

Relationship of left ventricular global longitudinal strain with cardiac autonomic denervation as assessed by 123I-mIBG scintigraphy in patients with heart failure with reduced ejection fraction submitted to cardiac resynchronization therapy : Assessment of cardiac autonomic denervation by GLS in patients with heart failure with reduced ejection fraction submitted to CRT.

BACKGROUND: Heart failure (HF) is associated with cardiac autonomic denervation (AD), which can be non-invasively assessed by 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy and has prognostic implications. We aimed to study the relationship between myocardial contractility assessed by global longitudinal strain (GLS) and AD assessed by 123I-mIBG scintigraphy in advanced HF. METHODS/RESULTS: BETTER-HF is a prospective randomized clinical trial including HF patients (pts) submitted to cardiac resynchronization therapy (CRT) who are submitted to a clinical, echocardiographic, and scintigraphic assessment before and 6 months after CRT. 81 pts were included. An echocardiographic response (absolute increase in left ventricular ejection fraction ≥ 10%) was observed in 73.7% of pts. A higher baseline late heart-to-mediastinum ratio (HMR) was associated with a better echocardiographic response. There was a significant association between late HMR and GLS at baseline and 6 months. At baseline, GLS had an AUC of 0.715 for discrimination for a late HMR < 1.6. A GLS cut-off of - 9% maximized the likelihood of correctly classifying a pt as having severe AD (HMR < 1.6). CONCLUSION: Myocardial contractility as assessed by GLS is moderately correlated with AD as assessed by 123I-mIBG scintigraphy and has a good discrimination for the identification of severe cardiac denervation. GLS may allow for a more readily accessible estimation of the degree of AD in advanced HF pts.

A Post hoc analysis on rhythm and high intensity interval training in cardiac resynchronization therapy.

Objectives. Evaluate the effects of a 6-month High Intensity Interval Training (HIIT) program on (1) functional capacity and health-related quality of life, (2) multiple blood biomarkers, (3) echocardiographic parameters, and (4) exercise performance, in patients in cardiac resynchronization therapy (CRT) stratified by the presence of atrial fibrillation (AF), targeting the following questions: (1) Does CRT provide similar benefits in patients in AF and sinus rhythm (SR)?; and (2) Does HIIT provides similar benefits in patients in AF and SR? Design. Estimates were available at baseline and 6 months after CRT implantation in 37 patients with heart failure. Patients were randomized after CRT to a 24-week HIIT group or to a usual care group (CON). In this sub-analysis, HIIT (AF = 7; SR = 11) and CON (AF = 9; SR = 10) were stratified by the presence of AF. Results. Patients in AF benefitted to a lesser degree from CRT in functional status than patients in SR (23.8-46.0%). However, HIIT induced superior improvements in patients in AF compared to CON (23.9-61.0%). Decreases in TNF-α (8.5-42.9%), BNP (15.3-34.6%) and left ventricular mass (9.6-26.2%) were only observed in patients in SR, whereas increases in peak oxygen uptake were only observed in patients in AF (19.5-23.2%). HIIT improved exercise capacity (8.8-59.4%) in patients in SR. Conclusions. Patients in AF or SR undergoing CRT demonstrated distinct benefits from device implantation and from HIIT as an adjunctive therapeutic strategy. This suggests that both mainstay and adjunctive therapeutics may need to be managed differently in patients in AF and SR.

High-intensity interval training in cardiac resynchronization therapy: a randomized control trial.

AIMS: To determine the effects of high-intensity interval training (HIIT) following cardiac resynchronization therapy (CRT) implantation in patients with chronic heart failure (CHF), on noninvasive estimates of systolic ventricular function, exercise performance, severity of symptoms and quality of life. METHODS: Cardiopulmonary exercise testing, resting transthoracic echocardiogram and health-related quality of life assessment were obtained before and at 6 months after CRT implantation in 37 patients with moderate-to-severe CHF. Patients were randomized after CRT to either a 24-week HIIT group (90-95% peak heart rate, 2 days per week) or to a usual care group (CON). Mixed design 2 × 2 repeated measures ANOVA were used to test for differences within and in-between groups. RESULTS: Improvements in health-related quality of life (HIIT = 98.54%, CON = 123.47%), NYHA class (HIIT = 43.44%, CON = 38.30%) HR recovery at minute 1 (HIIT = 32.32%, CON = 42.94%), pulse pressure at peak effort (HIIT = 14.06%, CON = 9.52%, LVEF (HIIT = 42.17%, CON = 51.10%) and LV Mass (HIIT = 13.26%, CON = 11.88%) were similar in both groups (p > 0.05). Significant increases in CPET duration in the HIIT group (25.94%), and increases in peak VO2 (HIIT = 8.64%, CON = 4.85%) and percent-predicted VO2 (HIIT = 10.57%, CON = 4.26%) in both groups, were observed in the intention-to-treat analysis. CONCLUSION: Six months of HIIT in patients in CRT did not further improved indices of functional capacity and health-related quality of life, and LV structure and function, compared to CRT alone. However, HIIT led to further improvements in exercise performance. It remains unclear whether HIIT benefits patients in CRT to a similar degree as more conventional forms of exercise training previously shown to maximize benefits in CRT. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov . Unique identifier: NCT02413151.

Susceptibility of human villous (BeWo) and extravillous (HTR-8/SVneo) trophoblast cells to Toxoplasma gondii infection is modulated by intracellular iron availability.

Congenital toxoplasmosis is a serious health problem that can lead to miscarriage. HTR-8/SVneo is a first trimester extravillous trophoblast, while BeWo is a choriocarcinoma with properties of villous trophoblast cells. In the placenta, iron is taken up from Fe-transferrin through the transferrin receptor being the ion an important nutrient during pregnancy and also for Toxoplasma gondii proliferation. The aim of this study was to evaluate the role of iron in T. gondii proliferation in BeWo and HTR-8/SVneo cells and in human chorionic villous explants. The cells were infected with T. gondii, iron supplemented or deprived by holo-transferrin or deferoxamine, respectively, and parasite proliferation and genes related to iron balance were analyzed. It was verified that the addition of holo-transferrin increased, and DFO decreased the parasite multiplication in both trophoblastic cells, however, in a more expressive manner in HTR-8/SVneo, indicating that the parasite depends on iron storage in trophoblastic cells for its growth. Also, tachyzoites pretread with DFO proliferate normally in trophoblastic cells demonstrating that DFO itself does not interfere with parasite proliferation. Additionally, T. gondii infection induced enhancement in transferrin receptor mRNA expression levels in trophoblastic cells, and the expression was higher in HTR-8/SVneo compared with BeWo. Finally, DFO-treatment was able to reduce the parasite replication in villous explants. Thus, the iron supplementation can be a double-edged sword; in one hand, it could improve the supplement of an essential ion to embryo/fetus development, and on the other hand, could improve the parasite proliferation enhancing the risk of congenital infection.

Forensic Speaker Verification Using Ordinary Least Squares.

In Brazil, the recognition of speakers for forensic purposes still relies on a subjectivity-based decision-making process through a results analysis of untrustworthy techniques. Owing to the lack of a voice database, speaker verification is currently applied to samples specifically collected for confrontation. However, speaker comparative analysis via contested discourse requires the collection of an excessive amount of voice samples for a series of individuals. Further, the recognition system must inform who is the most compatible with the contested voice from pre-selected individuals. Accordingly, this paper proposes using a combination of linear predictive coding (LPC) and ordinary least squares (OLS) as a speaker verification tool for forensic analysis. The proposed recognition technique establishes confidence and similarity upon which to base forensic reports, indicating verification of the speaker of the contested discourse. Therefore, in this paper, an accurate, quick, alternative method to help verify the speaker is contributed. After running seven different tests, this study preliminarily achieved a hit rate of 100% considering a limited dataset (Brazilian Portuguese). Furthermore, the developed method extracts a larger number of formants, which are indispensable for statistical comparisons via OLS. The proposed framework is robust at certain levels of noise, for sentences with the suppression of word changes, and with different quality or even meaningful audio time differences.

Stochastic thermodynamics and entropy production of chemical reaction systems.

We investigate the nonequilibrium stationary states of systems consisting of chemical reactions among molecules of several chemical species. To this end, we introduce and develop a stochastic formulation of nonequilibrium thermodynamics of chemical reaction systems based on a master equation defined on the space of microscopic chemical states and on appropriate definitions of entropy and entropy production. The system is in contact with a heat reservoir and is placed out of equilibrium by the contact with particle reservoirs. In our approach, the fluxes of various types, such as the heat and particle fluxes, play a fundamental role in characterizing the nonequilibrium chemical state. We show that the rate of entropy production in the stationary nonequilibrium state is a bilinear form in the affinities and the fluxes of reaction, which are expressed in terms of rate constants and transition rates, respectively. We also show how the description in terms of microscopic states can be reduced to a description in terms of the numbers of particles of each species, from which follows the chemical master equation. As an example, we calculate the rate of entropy production of the first and second Schlögl reaction models.

A New Structural Health Monitoring Strategy Based on PZT Sensors and Convolutional Neural Network.

Preliminaries convolutional neural network (CNN) applications have recently emerged in structural health monitoring (SHM) systems focusing mostly on vibration analysis. However, the SHM literature shows clearly that there is a lack of application regarding the combination of PZT-(lead zirconate titanate) based method and CNN. Likewise, applications using CNN along with the electromechanical impedance (EMI) technique applied to SHM systems are rare. To encourage this combination, an innovative SHM solution through the combination of the EMI-PZT and CNN is presented here. To accomplish this, the EMI signature is split into several parts followed by computing the Euclidean distances among them to form a RGB (red, green and blue) frame. As a result, we introduce a dataset formed from the EMI-PZT signals of 720 frames, encompassing a total of four types of structural conditions for each PZT. In a case study, the CNN-based method was experimentally evaluated using three PZTs glued onto an aluminum plate. The results reveal an effective pattern classification; yielding a 100% hit rate which outperforms other SHM approaches. Furthermore, the method needs only a small dataset for training the CNN, providing several advantages for industrial applications.

Use of Savitzky-Golay Filter for Performances Improvement of SHM Systems Based on Neural Networks and Distributed PZT Sensors.

A considerable amount of research has focused on monitoring structural damage using Structural Health Monitoring (SHM) technologies, which has had recent advances. However, it is important to note the challenges and unresolved problems that disqualify currently developed monitoring systems. One of the frontline SHM technologies, the Electromechanical Impedance (EMI) technique, has shown its potential to overcome remaining problems and challenges. Unfortunately, the recently developed neural network algorithms have not shown significant improvements in the accuracy of rate and the required processing time. In order to fill this gap in advanced neural networks used with EMI techniques, this paper proposes an enhanced and reliable strategy for improving the structural damage detection via: (1) Savitzky-Golay (SG) filter, using both first and second derivatives; (2) Probabilistic Neural Network (PNN); and, (3) Simplified Fuzzy ARTMAP Network (SFAN). Those three methods were employed to analyze the EMI data experimentally obtained from an aluminum plate containing three attached PZT (Lead Zirconate Titanate) patches. In this present study, the damage scenarios were simulated by attaching a small metallic nut at three different positions in the aluminum plate. We found that the proposed method achieves a hit rate of more than 83%, which is significantly higher than current state-of-the-art approaches. Furthermore, this approach results in an improvement of 93% when considering the best case scenario.

In vivo validation of a novel algorithm for automatic premature ventricular contractions recognition.

INTRODUCTION: Template-matching algorithms are routinely used in the catheter ablation of patients with premature ventricular contractions (PVCs). However, systematic analysis of the accuracy and spatial resolution of such systems is lacking. Therefore, the aim of this evaluation was to perform a systematic in vivo validation of performance of a novel automated template-matching algorithm. METHODS AND RESULTS: In a porcine model, paced beats simulating PVCs from different origins were investigated. The ability to discriminate between sinus rhythm and PVCs was tested by simulating PVCs using sequential pacing from different cardiac chambers. The accuracy of the algorithm in correctly classifying PVCs was reviewed by an independent investigator. In addition, the spatial resolution of pace matching was evaluated by assessing the QRS morphology discrimination at a distance of 0, 2, 4, and 6 mm of a simulated PVCs focus. The specificity of the algorithm for recognizing simulated PVCs was 99.6% and the sensitivity was 85.3%. There was a significant difference in the discrimination metric discrimination metric (with 0% being a perfect match and 100% being no correlation) between PVC origin (median 0%, interquartile range (IQR) 0-2%) versus at 2 mm (5%, IQR 2-7%), 4 mm (16%, IQR 11-21%), and 6 mm (24%, IQR 19-28%, P < 0.001 for all). The c-statistic for discrimination between PVC origin and a distance ≥ 2 mm was 0.93. CONCLUSIONS: Automated template matching had high specificity and sensitivity, with good spatial discrimination and a pace-mapping resolution in range of 2 mm. Clinical application of this algorithm may assist in the interventional treatment of patients with PVCs.