Mean nocturnal baseline impedance in gastro-esophageal reflux disease diagnosis: Should we strictly follow the Lyon 2 Consensus?

Clinical practice guidelines drive clinical practice and clinicians rely to them when trying to answer their most common questions. One of the most important position papers in the field of gastro-esophageal reflux disease (GERD) is the one produced by the Lyon Consensus. Recently an updated second version has been released. Mean nocturnal baseline impedance (MNBI) was proposed by the first Consensus to act as supportive evidence for GERD diagnosis. Originally a cut-off of 2292 Ohms was proposed, a value revised in the second edition. The updated Consensus recommended that an MNBI < 1500 Ohms strongly suggests GERD while a value > 2500 Ohms can be used to refute GERD. The proposed cut-offs move in the correct direction by diminishing the original cut-off, nevertheless they arise from a study of normal subjects where cut-offs were provided by measuring the mean value ± 2SD and not in symptomatic patients. However, data exist that even symptomatic patients with inconclusive disease or reflux hypersensitivity (RH) show lower MNBI values in comparison to normal subjects or patients with functional heartburn (FH). Moreover, according to the data, MNBI, even among symptomatic patients, is affected by age and body mass index. Also, various studies have proposed different cut-offs by using receiver operating characteristic curve analysis even lower than the one proposed. Finally, no information is given for patients submitted to on-proton pump inhibitors pH-impedance studies even if new and extremely important data now exist. Therefore, even if MNBI is an extremely important tool when trying to approach patients with reflux symptoms and could distinguish conclusive GERD from RH or FH, its values should be interpreted with caution.

NiOx Passivation in Perovskite Solar Cells: From Surface Reactivity to Device Performance.

Nonstoichiometric nickel oxide (NiOx) is one of the very few metal oxides successfully used as hole extraction layer in p-i-n type perovskite solar cells (PSCs). Its favorable optoelectronic properties and facile large-scale preparation methods are potentially relevant for future commercialization of PSCs, though currently low operational stability of PSCs is reported when a NiOx hole extraction layer is used in direct contact with the perovskite absorber. Poorly understood degradation reactions at this interface are seen as cause for the inferior stability, and a variety of interface passivation approaches have been shown to be effective in improving the overall solar cell performance. To gain a better understanding of the processes happening at this interface, we systematically passivated specific defects on NiOx with three different categories of organic/inorganic compounds. The effects on NiOx and the perovskite (MAPbI3) deposited on top were investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Here, we find that the perovskite's structural stability and film formation can be significantly affected by the passivation treatment of the NiOx surface. In combination with density functional theory (DFT) calculations, a likely origin of NiOx-perovskite degradation interactions is proposed. The surface passivated NiOx layers were incorporated into MAPbI3-based PSCs, and the influence on device performance and operational stability was investigated by current-voltage (J-V) characterization, impedance spectroscopy (IS), and open circuit voltage decay (OCVD) measurements. Interestingly, we find that a superior structural stability due to interface passivation must not relate to high operational stability. The discrepancy comes from the formation of excess ions at the interface, which negatively impacts all solar cell parameters.

Conductivity at varying frequencies as a method for differentiating strawberry ripeness and association with colour acceptance of strawberry nectars.

BACKGROUND: Identifying the best strawberries to produce colour stable nectars is a priority for the juice industry. Although riper strawberries produce nectars with better colour stability, variability between cultivars means that surface colour cannot be used as a single quality attribute to determine stability. Conductivity and bio-impedance measurements can be used to differentiate ripeness of strawberries. The commercially available PEF Control System (ELEA) can measure cell disruption by measuring conductivity at different frequencies. Updated software measured strawberry conductivity at 121 frequencies between 100 Hz and 1 MHz to determine whether conductivity at these frequencies could differentiate ripeness, and be compared with the colour acceptance and stability of nectars produced from these strawberries. RESULTS: A high-low ratio (HLR) was calculated by dividing the conductivity at frequency 1 MHz by conductivity at 1 kHz. HLR could be used to separate five strawberry ripeness stages, with decreasing HLR associated with increasing ripeness. HLR was then compared with the colour of nectars produced from these strawberries. Although there was a good correlation between HLR and an acceptable colour to consumers on initial production (r = -0.823, P < 0.001) and after 12 weeks of storage (-0.759, P < 0.001), cultivars differed greatly in both HLR and colour stability. Additionally, HLR had a strong correlation with firmness. CONCLUSION: The PEF Control System could be used to differentiate ripeness of strawberries by HLR, and therefore was associated with colour stability. However, no additional information on colour stability was gained from conductivity beyond what could already be deduced from differentiating ripeness based on surface colour. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Executing and facilitating the successful combined multichannel intraluminal impedance and pH monitoring study.

Successful multichannel intraluminal impedance and pH monitoring (MII-pHM) studies rely on constant attendants (CAs) or family members (and sometimes the patients themselves) to assist in the execution and facilitation of the MII-pHM study. While "pushing buttons" [corresponding to specific symptoms, body position (upright versus recumbent), and meal start and stop times] on the MII-pHM system recording box is indeed a big part of MII-pHM study execution and facilitation, there are other concerns and duties that are equally as important. This paper outlines some of the important duties of the study facilitator (or patient) during a MII-pHM study. When provided with the proper training, study facilitators invigilating the MII-pHM study will be better able to contribute to the data collection process and ultimately to produce data that when analyzed will lead to better interpretations, clinical recommendations, and good clinical outcomes. When executed properly, MII-pHM studies have the potential to assess diurnal exposure of the esophageal mucosa to gastric/duodenal contents, provide insight regarding the proximal extent of gastroesophageal reflux (GER), provide a measurement of the mean esophageal pH, and assess mucosal integrity and temporal relationship between GER and the symptoms of interest. While several groups have offered recommendations for proper execution of the MII-pHM study, to our knowledge, there have not been publications wherein recommendations were compiled to form a single source document.

Electrical transport and dielectric relaxation mechanism in Zn0.5Cd0.5Fe2O4 spinel ferrite: A temperature- and frequency-dependent complex impedance study.

In the present study, the frequency-dependent dielectric relaxation and electrical conduction mechanisms in sol-gel-derived Zn0.5Cd0.5Fe2O4 (ZCFO) spinel ferrite were studied in the temperature range of 343-438 K. The formation of the ZCFO spinel ferrite phase with space group Fd3m was confirmed by X-ray diffraction analysis. The dielectric relaxation and electrical conduction mechanisms were studied using complex impedance spectroscopy (CIS). In the Nyquist plots, depressed semicircles were fitted with an equivalent circuit model with configuration (RGBQGB) (RGQG), signifying the contributions from grain boundaries and grains to the charge transport mechanism in the sample. The frequency-dependent AC conductivity was found to follow Jonscher's power law, and the frequency exponent term depicted the overlapping large polaron hopping (OLPH) model as the dominant transport mechanism. The activation energies for conductivity, electric modulus and impedance were calculated to identify the nature of the charge carriers governing the relaxation and conduction mechanisms in the prepared sample. Complex modulus studies confirmed the non-Debye type of dielectric relaxation, whereas tangent loss and dielectric constant analyses confirmed the thermally activated hopping mechanism of charge carriers in Zn0.5Cd0.5Fe2O4 spinel ferrite.

The role of pulse wave analysis indexes for critically ill patients: a narrative review.

OBJECTIVE: Arterial pulse wave analysis (PWA) is now established as a powerful tool to investigate the cardiovascular system, and several clinical studies have shown how PWA can provide valuable prognostic information over and beyond traditional cardiovascular risk factors. Typically these techniques are applied to chronic conditions, such as hypertension or aging, to monitor the slow structural changes of the vascular system which lead to important alterations of the arterial PW. However, their application to acute critical illness is not currently widespread, probably because of the high hemodynamic instability and acute dynamic alterations affecting the cardiovascular system of these patients. APPROACH: In this work we propose a review of the physiological and methodological basis of PWA, describing how it can be used to provide insights into arterial structure and function, cardiovascular biomechanical properties, and to derive information on wave propagation and reflection. The applicability of these techniques to acute critical illness, especially septic shock, is extensively discussed, highlighting the feasibility of their use in acute critical patients and their role in optimizing therapy administration and hemodynamic monitoring. SIGNIFICANCE: The potential for the clinical use of these techniques lies in the ease of computation and availability of arterial blood pressure signals, as invasive arterial lines are commonly used in these patients. We hope that the concepts illustrated in the present review will soon be translated into clinical practice.

Quantitative phenotyping of crop roots with spectral electrical impedance tomography: a rhizotron study with optimized measurement design.

BACKGROUND: Root systems are key contributors to plant health, resilience, and, ultimately, yield of agricultural crops. To optimize plant performance, phenotyping trials are conducted to breed plants with diverse root traits. However, traditional analysis methods are often labour-intensive and invasive to the root system, therefore limiting high-throughput phenotyping. Spectral electrical impedance tomography (sEIT) could help as a non-invasive and cost-efficient alternative to optical root analysis, potentially providing 2D or 3D spatio-temporal information on root development and activity. Although impedance measurements have been shown to be sensitive to root biomass, nutrient status, and diurnal activity, only few attempts have been made to employ tomographic algorithms to recover spatially resolved information on root systems. In this study, we aim to establish relationships between tomographic electrical polarization signatures and root traits of different fine root systems (maize, pinto bean, black bean, and soy bean) under hydroponic conditions. RESULTS: Our results show that, with the use of an optimized data acquisition scheme, sEIT is capable of providing spatially resolved information on root biomass and root surface area for all investigated root systems. We found strong correlations between the total polarization strength and the root biomass ( R 2 = 0.82 ) and root surface area ( R 2 = 0.8 ). Our findings suggest that the captured polarization signature is dominated by cell-scale polarization processes. Additionally, we demonstrate that the resolution characteristics of the measurement scheme can have a significant impact on the tomographic reconstruction of root traits. CONCLUSION: Our findings showcase that sEIT is a promising tool for the tomographic reconstruction of root traits in high-throughput root phenotyping trials and should be evaluated as a substitute for traditional, often time-consuming, root characterization methods.

Deep-Learning-Guided Electrochemical Impedance Spectroscopy for Calibration-Free Pharmaceutical Moisture Content Monitoring.

The moisture content of pharmaceutical powders can significantly impact the physical and chemical properties of drug formulations, solubility, flowability, and stability. However, current technologies for measuring moisture content in pharmaceutical materials require extensive calibration processes, leading to poor consistency and a lack of speed. To address this challenge, this study explores the feasibility of using impedance spectroscopy to enable accurate, rapid testing of moisture content of pharmaceutical materials with minimal to zero calibration. By utilizing electrochemical impedance spectroscopy (EIS) signals, we identify a strong correlation between the electrical properties of the materials and varying moisture contents in pharmaceutical samples. Equivalent circuit modeling is employed to unravel the underlying mechanism, providing valuable insights into the sensitivity of impedance spectroscopy to moisture content variations. Furthermore, the study incorporates deep learning techniques utilizing a 1D convolutional neural network (1DCNN) model to effectively process the complex spectroscopy data. The proposed model achieved a notable predictive accuracy with an average error of just 0.69% in moisture content estimation. This method serves as a pioneering study in using deep learning to provide a reliable solution for real-time moisture content monitoring, with potential applications extending from pharmaceuticals to the food, energy, environmental, and healthcare sectors.

Design and application of an ultrasensitive and selective tobromycin electrochemiluminescence aptasensor using MXene /Ni/Sm-LDH-based nanocomposite.

Using a chemiluminescence reaction between luminol and H2O2 in basic solution, an ultrasensitive electrochemiluminescence (ECL) aptasensor was developed for the determination of tobramycin (TOB), as an aminoglycoside antibiotic. Ti3C2/Ni/Sm-LDH-based nanocomposite effectively catalyzes the oxidation of luminol and decomposition of H2O2, leading to the formation of different reactive oxygen species (ROSs), thus amplifying the ECL signal intensity of luminol, which can be used for the determination of TOB concentration. To evaluate the performance of the electrochemiluminescence aptasensor and synthesized nanocomposite, different methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses were performed. The considerable specific area, large number of active sites, and enhanced electron transfer reaction on this nanocomposite led to the development of an ECL aptasensor with high sensitivity and electrocatalytic activity. After optimizing the preparation method and analysis conditions, the aptasensor revealed a wide linear response ranging from 1.0 pM to 1.0 µM with a detection limit of 18 pM, displaying outstanding accuracy, specificity, and response stability. The developed ECL sensor was found to be applicable to the determination of TOB in human serum samples and is anticipated to possess excellent clinical potentials for detecting other antibiotics, as well.

Postoperative Rehabilitation Program for Increasing Muscle Mass in Patients With Hip Fracture: A Retrospective Study.

BACKGROUND: Hip fractures are most likely to occur in older people, and after hip surgery muscle mass and the ability to perform activities of daily living often decline. In this study, we conducted inpatient rehabilitation after surgery for hip fracture and measured changes in muscle mass and physical performance. METHODS: We retrospectively analyzed patients aged 65 years or older who underwent surgery (prosthetic replacement or internal fixation) and inpatient rehabilitation for hip fracture at our hospital between August and December 2020. The training included a joint range of motion exercise, muscle-strengthening exercise, gait training, early mobilization training, and neuromuscular electrical stimulation. We measured the following factors after one and six weeks postoperatively: muscle mass, body weight, fat mass, grip strength, bilateral knee extension strength, ability to walk, and ability to perform activities of daily living. RESULTS: Seventeen patients were included. Median age was 84 years (interquartile range, 72-90). Lower limbs skeletal muscle mass increased (median 4.8 kg to 4.9 kg, p = 0.045), while upper limbs skeletal muscle mass and body weight decreased (median 1.2 kg to 1.1 kg, p = 0.0027), (median 46.8 kg to 45.5 kg, p = 0.0039), respectively. Total skeletal muscle mass and fat mass remained unchanged. Grip strength was maintained, and knee extension muscle strength on the healthy and affected sides increased (healthy side median 10.7 kgf to 13.7 kgf, p = 0.019; affected side median 5.5 kgf to 9.5 kgf, p < 0.001). All patients exhibited improved ability to perform activities of daily living; however, 52.9% of patients regained their pre-injury walking ability. CONCLUSIONS: Our rehabilitation program increased lower limb skeletal muscle mass in patients with hip fractures.

Breath-by-breath assessment of acute pulmonary edema using electrical impedance tomography, spirometry and volumetric capnography in a sheep (Ovis Aries) model.

Background: The bedside diagnosis of acute pulmonary edema is challenging. This study evaluated the breath-by-breath information from electrical impedance tomography (EIT), respiratory mechanics and volumetric capnography (VCap) to assess acute pulmonary edema induced by xylazine administration in anesthetized sheep. Objective: To determine the ability and efficiency of each monitoring modality in detecting changes in lung function associated with onset of pulmonary edema. Methods: Twenty healthy ewes were anesthetized, positioned in sternal (prone) recumbency and instrumented. Synchronized recordings of EIT, spirometry and VCap were performed for 60 s prior to start of injection, during xylazine injection over 60 s (0-60 s) and continuously for 1 min (60-120 s) after the end of injection. After visual assessment of the recorded mean variables, statistical analysis was performed using a mixed effect model for repeated measures with Bonferroni's correction for multiple comparisons, to determine at which breath after start of injection the variable was significantly different from baseline. A significant change over time was defined as an adjusted p < 0.05. All statistics were performed using GraphPad Prism 0.1.0. Results: Electrical impedance tomography showed significant changes from baseline in all but two variables. These changes were observed simultaneously during xylazine injection at 48 s and were consistent with development of edema in dependent lung (decreased end-expiratory lung impedance, ventilation in centro-ventral and ventral lung region) and shift of ventilation into non-dependent lung (decreased non-dependent silent spaces and increased center of ventilation ventral to dorsal and increased ventilation in centro-dorsal and dorsal lung region). All changes in lung mechanics also occurred during injection, including decreased dynamic respiratory system compliance and increased peak expiratory flow, peak inspiratory pressure and airway resistance at 48, 54 and 60 s, respectively. Changes in VCap variables were delayed with all occurring after completion of the injection. Conclusion: In this model of pulmonary edema, EIT detected significant and rapid change in all assessed variables of lung function with changes in regional ventilation indicative of pulmonary edema. Volumetric capnography complemented the EIT findings, while respiratory mechanics were not specific to lung edema. Thus, EIT offers the most comprehensive method for pulmonary edema evaluation, including the assessment of ventilation distribution, thereby enhancing diagnostic capabilities.

Evaluation of Ablation Parameters to Predict Irreversible Lesion Size During Pulsed Field Ablation.

BACKGROUND: During pulsed field ablation (PFA), relationships between ablation parameters (contact force [CF], number of burst pulses, impedance decrease, and electrode temperature) and lesion size in beating hearts have not been well validated. METHODS: A 7F-catheter with a 3.5-mm ablation electrode and CF sensor (ThermoCool SmartTouch SF-Dual-Energy, Biosense Webster, Inc, Irwindale, CA) was connected to a PFA system (TRUPULSE2, Biosense Webster, Inc). In 11 closed-chest swine, biphasic PFA current was delivered between the ablation electrode and the skin patch at 219 sites in left ventricle and right ventricle using 12, 18, and 24 burst pulses with 4 different levels of CF: (1) low (n=57; CF, 4-15g; median, 10g); (2) moderate (n=60; CF, 16-30g; median, 22.5g); (3) high (n=68; CF, 32-65g; median, 40g); and (4) no electrode contact (n=34), 2 mm away from the endocardium. Swine were euthanized 2 hours after ablation, and lesion size was measured using triphenyl tetrazolium chloride staining. RESULTS: All PFA lesions with electrode-myocardium contact were well demarcated with triphenyl tetrazolium chloride staining, demonstrating (1) pale central zone (contraction band necrosis with minimal coagulation necrosis), (2) dark brown zone (contraction band necrosis with hemorrhage), and (3) hyperstained red zone by triphenyl tetrazolium chloride (unaffected normal myocardium with preserved mitochondrial activity, consistent with reversible zone). Lesion depth increased significantly with increasing CF and the number of PFA burst pulses. An exponential/logarithmic formula combined with CF and the number of PFA burst pulses correlated lesion depth with high accuracy: R=0.809, P<0.0001, ±1.0-mm accuracy in 128 of 163 (79%) lesions, and ±1.5-mm accuracy in 153 of 163 (94%) lesions. Impedance decrease and electrode temperature were poor predictors of lesion size. There were no detectable lesions resulting from ablation without electrode contact. CONCLUSIONS: Acute PFA ventricular lesions demonstrate irreversible and reversible lesion boundaries. Electrode-tissue contact is required for effective lesion formation. Lesion depth increases significantly with increasing CF and PFA burst pulses. A new exponential/logarithmic formula combined with CF and the number of PFA burst pulses correlates lesion depth with high accuracy.

Comparative evaluation of single versus double leg raise maneuver in high-resolution esophageal manometry.

BACKGROUND: The straight leg raise (SLR) maneuver, often performed during esophageal manometry, requires patients to lift their leg(s) to augment intraabdominal pressure (IAP). Diverse techniques have been applied for SLR. This study aimed to evaluate and compare the effects of SLR between single and double leg raises. METHODS: During esophageal manometry, patients were asked to raise one leg, followed by elevating both legs. The efficacy of SLR for (1) detecting hiatal hernia, (2) increasing IAP, and (3) predicting gastroesophageal reflux disease (GERD) with intraesophageal pressure (IEP) was assessed. The value of change in impedance to indicate reflux during SLR in predicting esophageal acid exposure was investigated. KEY RESULTS: The leg raise procedures were performed in 86 patients undergoing high-resolution esophageal manometry. Both the single and double leg raises exhibited a higher hiatal hernia detection rate compared to the landmark (p = 0.008 and 0.005, respectively). Double leg raise was more effective in raising IAP by >50% compared to single leg raise (100% vs. 65.1%, p < 0.001), increasing yield by 53.6%. The change in IAP showed a positive correlation with the change in IEP during double leg raise (r = 0.31; p = 0.004), higher than that for single leg raise (r = 0.23; p = 0.03). Lower intraesophageal impedance during SLR was associated with AET > 6% with double leg raise (1.5 kΩ vs. 2.5 kΩ, p = 0.04). CONCLUSIONS & INFERENCES: Our study demonstrates the efficacy of both single and double leg raise maneuvers during HREMI in increasing hiatal hernia detection and possible value in predicting GERD. The double leg raise resulted in a higher rate of effective increase in IAP, potentially enabling more patients to undergo effective SLR during HREMI.

Active decompression during automated head-up cardiopulmonary resuscitation.

BACKGROUND: The combination of active compression-decompression cardiopulmonary resuscitation (ACD-CPR) with an impedance threshold device (ITD) and controlled head-up positioning (AHUP-CPR) is associated with improved outcomes compared with conventional CPR (C-CPR). This study focused on the role of active decompression (AD) during AHUP-CPR. METHODS: Farm pigs (n = 10, ∼40 kg) were anesthetized, intubated and ventilated. Physiological parameters and right ventricular pressure-volume loops were recorded continuously. Ventricular fibrillation was induced and left untreated for 10 mins, followed by automated C-CPR (2 min), ACD + ITD CPR in the flat position (2 min), and then AHUP-CPR with 3 cm of lift above the neutral chest position. After 15 min of CPR, AD was discontinued and then restarted incrementally to 4 cm. Data were analyzed with a linear mixed-effects model, using random intercepts for individual pigs. RESULTS: Upon cessation of AD during AHUP-CPR, decompression right atrial pressure (+59%) increased (p < 0.01), whereas multiple hemodynamic parameters positively associated with perfusion, including coronary (-25%) and cerebral perfusion pressures (-11%), end-tidal CO2 (-13%), stroke volume and cardiac output (-26%), decreased immediately and significantly with p < 0.05. Restoration of AD reduced right atrial pressure and increased positive perfusion parameters in an incremental manner. Only with ≥ 3 cm of AD were all hemodynamic parameters restored to ≥ 90% of pre-AD discontinuation levels. CONCLUSION: Full chest wall lift, achieved with ≥ 3 cm of AD, was needed to maintain and optimize hemodynamics during AHUP-CPR in pigs. These findings should be considered when optimizing care with this new approach.

A low-cost protocol for reconditioning of deep-brain neural microelectrodes with material failure for electrophysiology recording.

To date, a myriad of neural microelectrodes has been meticulously developed, but the focus of existing literature predominantly revolves around fabrication methodologies rather than delving into the reconditioning processes or strategies for salvaging electrodes exhibiting diminished performance due to material failure. This study aims to elucidate the underlying factors contributing to the degradation in performance of neural microelectrodes. Additionally, it introduces a comprehensive, cost-effective protocol for the reconditioning and repurposing of electrodes afflicted by material failure, tailored for a broad spectrum of electrode types. The efficacy of the proposed reconditioning protocol is substantiated through experimental validation on single-site tungsten microelectrodes. The results of neural signal recording unequivocally demonstrate the successful restoration of a substantial number of electrodes, underscoring the protocol's effectiveness.

Esophageal impedance planimetry during per-oral endoscopic myotomy guides myotomy extent.

INTRODUCTION: Peroral endoscopic myotomy (POEM) is the standard treatment for achalasia. Functional luminal imaging probe (FLIP) technology enables objective measurement of lower esophageal sphincter (LES) geometry, with literature linking specific values to improved post-POEM outcomes. Our study assesses FLIP's intraoperative use in evaluating myotomy extent in real-time. METHODS: Retrospective data from all patients undergoing POEM with intraoperative FLIP measurements were extracted from June 2020 to January 2023. The primary endpoint was intraoperative FLIP measurements, management changes, and symptom improvement (Eckardt score). RESULTS: Fourteen patients (age 56 ± 14 years, BMI 28 ± 7 kg/m2) were identified. Most patients were female (64%). Predominantly, patients presented with type II achalasia (50%). FLIP measurements were taken before and after myotomy, demonstrating increases in mean distensibility index (DI) 1.6 ± 1. 4 to 5.4 ± 2.1 mm2/mmHg (p < 0.05) and mean diameter (Dmin) 6 ± 1.8 to 10.9 ± 2.3 mm (p < 0.05) at 50 ml balloon fill. Additional myotomy was performed in one patient when an inadequate increase in FLIP values were noted. Mean operative time was 98 ± 28 min, and there were no intraoperative complications. At the 30-day follow-up, median Eckardt score decreased from mean a preoperative score of 7 ± 2 to a post-operative mean of 2 ± 3, with 10 patients (78%) having a score ≤ 2. In total, four patients experienced symptom recurrence, with repeat FLIP values revealing a significant decrease in DI from 7 ± 2.2 post-POEM to 2.5 ± 1.5 at recurrence. FLIP technology identified LES pathology in 3 out of 4 (75%) patients, facilitating referral to LES-directed therapy. CONCLUSION: Our study adds to the literature supporting the use of FLIP technology during the POEM procedure, with most patients achieving ideal values after a standard-length myotomy. This suggests the potential benefits of shorter myotomies guided by FLIP to achieve comparable outcomes and reduce postoperative GERD risk. Collaborative standardization of study designs and outcome measures is crucial for facilitating prospective trials and cross-setting outcome comparisons.

Bioimpedance analysis predicts worsening events in outpatients with heart failure and reduced ejection fraction.

AIMS: Heart failure (HF) with reduced left ventricle ejection fraction (LVEF) is an entity with poor prognosis characterized by decompensations. Bioelectrical impedance analysis (BIA) is used to assess volume overload (VO) and may be useful to identify apparently stable HF outpatients at risk of decompensation. The aim of this study is to analyse whether VO assessed by BIA is associated with worsening heart failure (WHF) in stable outpatients with HF and reduced LVEF (HFrEF). METHODS AND RESULTS: This is a prospective single-centre observational study. Consecutive stable HF outpatients with LVEF below 40% underwent BIA, transthoracic echocardiography, blood sampling, and physical examination and were followed up for 3 months. VO was defined as the difference between the measured weight and the dry weight assessed by BIA. Demographic, clinical, anthropometric, echocardiographic, and analytical parameters were recorded. The primary endpoint was WHF, defined by visits to the emergency department for HF or hospitalization for HF. A total of 100 patients were included. The median VO was 0.5 L (interquartile range 0-1.6 L). Eleven patients met the primary endpoint. Univariate binary logistic regression analysis showed that left ventricle filling pressures assessed by E/e', N-terminal pro B-type natriuretic peptide, inferior vena cava dilatation (≥21 mm), signs of congestion, and VO were associated with the primary endpoint. Binary logistic regression multivariate analysis showed that VO was the only independent predictor for the primary endpoint (adjusted OR 2.7; 95% CI 1.30-5.63, P = 0.008). Multivariate Cox regression analysis also showed an adjusted hazard ratio (HR) for VO of 2.03; 95% CI 1.37-3.02, P < 0.001. Receiver-operating characteristic curve analysis showed an area under the curve for VO of 0.88 (95% CI 0.79-0.97, P < 0.001) with an optimal cut-off of 1.2 L. CONCLUSIONS: VO assessed by BIA is independently associated with WHF in stable outpatients with HFrEF at 3 months.

Experimental results of a 330 GW impedance-matched Marx generator.

Impedance-matched Marx generators (IMGs) are considered next generation pulsed-power drivers because of their long lifetime (> 10,000 shots), repetition rate (> 0.1-Hz), fast rise time (~ 100-ns), and high-energy-delivery efficiency (~ 90%). "TITAN" is a 14-stage IMG designed to deliver 1-TW to a 2-Ω matched load. In this paper, design, simulation, and experimental results for six stages of TITAN including its triggering system, air delivery system, and pulse shaping are presented. To achieve efficiency over 85% and maximize the capability of an IMG, synchronized triggering, reduced pre-fire rate, and pulse shaping ability are crucial. In this paper, novel engineering solutions are introduced, tested, and proven to overcome those challenges. 6-stage TITAN, powered by 102 identical bricks and 102 field-distortion-triggered gas switches, could generate ~ 600-kA and ~ 700-kV across a ~ 0.9-Ω matched load when fully charged to ± 100-kV. In these experiments, 6-stage TITAN is tested up to ± 70-kV charge voltage which delivers a peak power of 330-GW to a 1.2-Ω resistive load.

Non-Faradaic Impedimetric Detection of Heavy Metal Ions via a Hybrid Nanoparticle-DNAzyme Biosensor.

Due to rapid industrialization, novel water-quality monitoring techniques for the detection of highly toxic and hazardous heavy metal ions are essential. Herein, a hybrid noble nanoparticle/DNAzyme electrochemical biosensor is proposed for the simultaneous and label-free detection of Pb2+ and Cr3+ in aqueous solutions. The sensor is based on the combination of a two-dimensional naked-platinum nanoparticle film and DNAzymes, whose double-helix configuration disassembles into smaller fragments in the presence of target-specific heavy metal ions. The electrochemical behavior of the fabricated sensor was investigated with non-faradaic electrochemical impedance spectroscopy (EIS), resulting in the successful detection of Pb2+ and Cr3+ well below their maximum permitted levels in tap water. So far, there has been no report on the successful detection of heavy metal ions utilizing the non-faradaic electrochemical impedance spectroscopy technique based on advanced nanomaterials paired with DNAzymes. This is also one of the few reports on the successful detection of chromium (III) via a sensor incorporating DNAzymes.

Automated software-derived supine baseline impedance is highly correlated with manual nocturnal baseline impedance for the diagnosis of GERD.

BACKGROUND: Mean nocturnal baseline impedance (MNBI) can improve diagnostic accuracy for gastroesophageal reflux disease (GERD), but must be manually calculated and is not routinely reported. We aimed to determine how automated software-derived mean supine baseline impedance (MSBI), a potential novel GERD metric, is related to MNBI. METHODS: Consecutively obtained pH-impedance studies were assessed. Manually extracted MNBI was compared to MSBI using paired t-test and Spearman's correlations. KEY RESULTS: The correlation between MNBI and MSBI was very high (ρ = 0.966, p < 0.01). CONCLUSIONS & INFERENCES: The ease of acquisition and correlation with MNBI warrant the routine clinical use and reporting of MSBI with pH-impedance studies.