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During the first phase of the ITER Pre-Fusion Power Operations (PFPO-1), the Electron Cyclotron Radio Frequency system will be the main heating and current drive source [1]. Evaluations of the L-H power threshold [2] have shown that H-mode is unlikely to be achieved in PFPO-1 scenarios at half-field (B0=2.65T). For this reason, the use of one-third field scenarios in an early phase might help to access H-mode. This means that the EC Heating (ECH) system, with gyrotrons operating at 170 GHz, would then rely on n=3 harmonic resonance. Using a lower frequency, namely 104 GHz, could allow the exploitation of n=2 harmonic resonance, improving heating efficiency and facilitating EC-assisted breakdown which has not been demonstrated yet for n=3 harmonic. This work presents a preliminary evaluation of the performances of an EC system using the two frequencies in a B0=1.8T scenario (obtained by adequately rescaling a reference half-field scenario [3]) via a parametric scan of density/temperature profiles, to cover the range of possible values expected to occur during the operations and provide an estimation of the parameter space region where the use of each frequency allows a good absorption efficiency.

In the initial phase of a plasma discharge with EC-assisted breakdown, the wave-particle interaction is nonlinear and wave trapping provides the mechanism for transition from a very low energy state to a much larger energy state. A Hamiltonian adiabatic approach provides the condition for the energy variation to occur in a rigorous way, together with quantitative estimate as a function of the wave frequency, harmonic number, polarisation and EC power and beam width, for the first, and second cyclotron harmonic. The interaction is highly localized in space close to the EC resonance. The spatial profile of the energy gain are reported together with the estimates of the width of the radial region where the interaction takes place in the case of a tokamak configuration. The analysis provides a physics based description of the process as well as indications for an optimized experimental setup.

Electron Cyclotron (EC) wave interaction with very low temperature electrons in conditions like those occurring for EC-assisted plasma breakdown is investigated via the Hamiltonian adiabatic formalism. Estimates of interest for applications to present tokamak experiments are derived. The analysis allows ultimately to derive analytically the particle energy gain per single beam crossing and to characterize the dependency of the maximum possible energy variation as a function of the wave frequency, harmonics and polarization and EC power and beam width. The investigation confirms that electrons can easily gain energies well above the ionization energy in most conditions, as observed in experiments.

Time dependent simulations that evolve consistently the magnetic equilibrium and plasma pressure profiles and the width and frequency rotation of magnetic islands under the effect of the Electron Cyclotron feedback system are used to assess whether the control of NTMs on ITER is compatible with other simulataneous functionalities of the EC system, like core heating and current profile tailoring, or sawtooth control. Results indicate that the power needs for control can be reduced if the EC power is reserved and if pre-emptive control is used as opposed to an active search for an already developed island.

The four ITER Electron Cyclotron Upper Launchers (UL) are designed to control Magneto- Hydrodynamic instabilities with the deposition of Electron Cyclotron power. According to the present design, each launcher comprises two rows of four input waveguides, whose output beam is focused and driven towards the plasma by four sets of mirrors. In order to study the beam-launcher interaction throughout quasi-optical propagation, with particular attention to straylight behaviour, and to verify analytical calculations, a 3D model of the UL optical system has been implemented with the electromagnetic code GRASP® and the Physical Optics method. Detailed description of the components are introduced: pure hybrid mode HE11 from cylindrical waveguide as input beams, real shapes of the mirror contours, semi-analytical description of the ellipsoidal surfaces of focussing mirrors. A conceptual calculation scheme has been developed in order to take into account not only the direct contribution of the single source on its next scatterer but also the first order indirect effects: crosstalk from different lines of the same row and crosstalk from different rows have been evaluated after reflection on the first and third set of mirrors. The evaluations presented have been performed on the preliminary UL design, the last major milestone before finalization; however, the numerical model is suitable to be applied to future evolutions of the setup and/or other configurations.

The 24 MW ITER Electron Cyclotron (EC) Heating and Current Drive (H&CD) system, operating at 170 GHz, consists of one Equatorial (EL) and four Upper Launchers (UL). The main task of the UL will be the control of Magneto-Hydrodynamic (MHD) activity such as Neoclassical Tearing Modes (NTMs) at the q=3/2 and q=2 surfaces, but it will also be needed for current profile tailoring in advanced scenarios and to assist plasma break-down and L- to H-mode transition. Moreover, it is required to be e.ective both when ITER will operate at nominal and reduced magnetic field magnitude. Here the performance of the UL is assessed through the study of the full temporal evolution of di.erent scenarios, including the reference ITER 15MA H-mode plasma, a half-field case at 2.65T, and a steady state scenario. The ECCD efficiency has been evaluated for a wide range of injection angles, deriving the optimal angles and the power required for NTMs stabilization, as well as the steering range necessary to reach the rational surfaces during all the phases of the discharge. The steering sensitivity to shifts of the target or aiming errors has been estimated too. The result is an assessment of the UL design requirements to achieve the desired functionalities, which, together with the engineering limits, will be used to drive the optimization and finalization of the UL design.

Abstract Background It is hypothesized that locomotion is achieved by means of rhythm generating networks (central pattern generators) and muscle activation generating networks. This modular organization can be partly identified from the analysis of the muscular activity by means of factorization algorithms. The activity of rhythm generating networks is described by activation signals whilst the muscle intervention generating network is represented by motor modules (muscle synergies). In this study, we extend the analysis of modular organization of walking to the case of robot-aided locomotion, at varying speed and body weight support level. Methods Non Negative Matrix Factorization was applied on surface electromyographic signals of 8 lower limb muscles of healthy subjects walking in gait robotic trainer at different walking velocities (1 to 3km/h) and levels of body weight support (0 to 30%). Results The muscular activity of volunteers could be described by low dimensionality (4 modules), as for overground walking. Moreover, the activation signals during robot-aided walking were bursts of activation timed at specific phases of the gait cycle, underlying an impulsive controller, as also observed in overground walking. This modular organization was consistent across the investigated speeds, body weight support level, and subjects. Conclusions These results indicate that walking in a Lokomat robotic trainer is achieved by similar motor modules and activation signals as overground walking and thus supports the use of robotic training for re-establishing natural walking patterns.

Abstract We propose a method for estimating wrist kinematics during dynamic wrist contractions from multi-channel surface electromyography (EMG). The algorithm extracts features from the surface EMG and uses dedicated multi-layer perceptron networks to estimate individual joint angles of the 3 degrees of freedom (DoFs) of the wrist. The method was designed with the aim of proportional and simultaneous control of multiple DoFs of active prostheses by unilateral amputees. Therefore, the proposed approach was tested in both unilateral transradial amputees and in intact-limbed control subjects. It was shown that the joint angles at the 3 DoFs of amputees can be estimated from surface EMG recordings , during mirrored bi-lateral contractions that simultaneously and proportionally articulated the 3 DoFs. The estimation accuracies of amputee subjects with long stumps were 62.5% ± 8.50% across all 3 DoFs, while accuracies of the intact-limbed control subjects were 72.0% ± 8.29%. The estimation results from intact-limbed subjects were consistent with earlier studies. The results from the current study demonstrated the feasibility of the proposed myoelectric control approach to provide a more intuitive myoelectric control strategy for unilateral transradial amputees.

Abstract This document provides a review of the techniques and therapies used in gait rehabilitation after stroke. It also examines the possible benefits of including assistive robotic devices and brain-computer interfaces in this field, according to a top-down approach, in which rehabilitation is driven by neural plasticity. The methods reviewed comprise classical gait rehabilitation techniques (neurophysiological and motor learning approaches), functional electrical stimulation (FES), robotic devices, and brain-computer interfaces (BCI). From the analysis of these approaches, we can draw the following conclusions. Regarding classical rehabilitation techniques, there is insufficient evidence to state that a particular approach is more effective in promoting gait recovery than other. Combination of different rehabilitation strategies seems to be more effective than over-ground gait training alone. Robotic devices need further research to show their suitability for walking training and their effects on over-ground gait. The use of FES combined with different walking retraining strategies has shown to result in improvements in hemiplegic gait. Reports on non-invasive BCIs for stroke recovery are limited to the rehabilitation of upper limbs; however, some works suggest that there might be a common mechanism which influences upper and lower limb recovery simultaneously, independently of the limb chosen for the rehabilitation therapy. Functional near infrared spectroscopy (fNIRS) enables researchers to detect signals from specific regions of the cortex during performance of motor activities for the development of future BCIs. Future research would make possible to analyze the impact of rehabilitation on brain plasticity, in order to adapt treatment resources to meet the needs of each patient and to optimize the recovery process.

Abstract Background For high usability, myo-controlled devices require robust classification schemes during dynamic contractions. Therefore, this study investigates the impact of the training data set in the performance of several pattern recognition algorithms during dynamic contractions. Methods A 9 class experiment was designed involving both static and dynamic situations. The performance of various feature extraction methods and classifiers was evaluated in terms of classification accuracy. Results It is shown that, combined with a threshold to detect the onset of the contraction, current pattern recognition algorithms used on static conditions provide relatively high classification accuracy also on dynamic situations. Moreover, the performance of the pattern recognition algorithms tested significantly improved by optimizing the choice of the training set. Finally, the results also showed that rather simple approaches for classification of time domain features provide results comparable to more complex classification methods of wavelet features. Conclusions Non-stationary surface EMG signals recorded during dynamic contractions can be accurately classified for the control of multi-function prostheses.

Background: Despite the established efficacy of achalasia treatments on symptomatic outcomes, there are limited data evaluating the treatment effect on esophageal dilatation. This study aimed to assess the effect achalasia treatment on esophageal dilatation and the effect of esophageal width reduction ("recoil") on clinical outcomes., Methods: Patients with type I or type II achalasia that completed high-resolution manometry (HRM), functional lumen imaging probe (FLIP), and timed barium esophagram (TBE) pre and post treatment were included. Esophageal width was measured using TBE. Focused subgroup analysis was performed on patients with normal posttreatment EGJ opening on FLIP. Good clinical outcomes were defined as barium column height of <5 cm at 5 min and Eckardt Score ≤3., Key Results: Sixty-nine patients (41% type I and 59% type II) were included. Esophageal width decreased from pre to post treatment mean (SD) 4.2 (1.3) cm-2.8 (1.2) cm; p < 0.01. In the normal post treatment EGJ opening subgroup, esophageal width was less in patients with good TBE outcome compared to poor outcome mean (SD) 2.2 (0.7) cm versus 3.2 (1.4) cm (p < 0.01), but did not differ in good versus poor symptomatic outcome groups. Esophageal width recoil >25% posttreatment was associated with a greater rate of good TBE outcome (71% vs. 50%, p = 0.04) and good symptomatic outcome (88% vs. 50%; p = 0.04)., Conclusions and Inferences: Esophageal recoil was associated with good achalasia treatment outcome in patients without posttreatment EGJ obstruction. This suggests that mechanical properties of the esophageal wall, likely associated with tissue remodeling, play a role in clinical outcomes following achalasia treatment., (© 2024 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Background and Aims: Some achalasia patients exhibit esophageal contractile activity on follow-up after treatment, yet its importance remains unclear. We aimed to identify factors associated with presence of contractility after treatment and to assess its impact on timed barium esophagram (TBE) and clinical outcomes., Methods: Patients with type I or II achalasia on baseline high-resolution manometry (HRM) who completed HRM, TBE, and functional lumen imaging probe (FLIP) after treatment were retrospectively identified. Contractility was defined on post-treatment HRM as presence of at least 1 supine swallow with DCI ≥100 mmHg s cm., Key Results: One hundred twenty-two patients were included (mean age 48 ± 17 years, 50% female). At follow-up evaluation after treatment (54% peroral endoscopic myotomy, 24% pneumatic dilation, 22% laparoscopic Heller myotomy), 61 (50%) patients had contractility on HRM. Patients with contractility (compared to those without) more frequently had type II achalasia (84% vs 57%, p = 0.001) and a post-treatment normal EGJ opening classification on FLIP (69% vs 49%; p < 0.001). In the subgroup of patients with post-treatment integrated relaxation pressure <15 mmHg and normal EGJ opening on FLIP (n = 53), those with contractility had a lower median column height on TBE at 1 min (4 vs 7 cm, p = 0.002) and 5 min (0 vs 5 cm, p = 0.001). In patients with "abnormal" EGJ metrics, patients with contractility showed lower symptom scores (median Eckardt score 2 vs 3, p = 0.03)., Conclusions & Inferences: Occurring more frequently in type II achalasia, and if adequate EGJ opening is achieved after treatment, esophageal contractility may contribute to improved esophageal emptying and improved symptoms in non-spastic achalasia. Preservation of esophageal body muscle could improve outcomes in these patients., (© 2023 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Background: The esophageal response to stepwise distension during the functional lumen imaging probe (FLIP) Panometry study often parallels high-resolution manometry (HRM) motility diagnoses. This study aimed to describe the changes in FLIP metrics during FLIP emptying, that is, reduced volume distension., Methods: Adult patients who completed FLIP and HRM for esophageal motility evaluation were included. Esophagogastric junction (EGJ) opening parameters were assessed during stepwise FLIP filling to volumes of 60 mL ("filling 60 mL"), then 70 mL, and then back to 60 mL ("emptying 60 mL"). HRM studies were analyzed per Chicago classification version 4.0 (CCv4.0)., Key Results: Among 265 patients included, HRM/CCv4.0 diagnoses included achalasia in 80 patients (30%), normal motility in 70 (26%), and ineffective esophageal motility (IEM) in 43 (16%). EGJ-distensibility index (DI) and EGJ diameter were greater during emptying 60 mL than filling 60 mL in achalasia, normal motility, and IEM (p values <0.002). If applying the emptying 60 mL EGJ-DI (vs. filling 60 mL EGJ-DI), EGJ opening classification changed from reduced EGJ opening to borderline EGJ opening in 31% of achalasia patients and in 2% of patients with normal motility or IEM. EGJ opening classification was unchanged in 69% achalasia and 96% of normal motility/IEM., Conclusions and Inferences: This study suggests that isotonic or auxotonic relaxation of the lower esophageal sphincter occurs with reduced volume distension in patients with achalasia and normal motility. The study also supports the importance of utilizing a standardized FLIP motility study protocol (i.e., controlled, stepwise filling to 50 mL, 60 mL, then 70 mL) to provide reliable and generalizable FLIP metrics to facilitate diagnosis of esophageal motility disorders., (© 2023 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Background: Panesophageal pressurization (PEP) defines type II achalasia on high-resolution-manometry (HRM) but some patients exhibit spasm after treatment. The Chicago Classification (CC) v4.0 proposed high PEP values as predictor of embedded spasm, yet supportive evidence is lacking., Methods: Fifty seven type II achalasia patients (47 ± 18 years, 54% males) with HRM and LIP Panometry before and after treatment were retrospectively identified. Baseline HRM and FLIP studies were analyzed to identify factors associated with post-treatment spasm, defined on HRM per CC v4.0., Results: Seven patients (12%) had spasm following treatment (peroral endoscopic myotomy 47%; pneumatic dilation [PD] 37%; laparoscopic Heller myotomy 16%). At baseline, greater median maximum PEP pressure (MaxPEP) values on HRM (77 vs 55 mmHg, p = 0.045) and spastic-reactive contractile response pattern on FLIP (43% vs 8%, p = 0.033) were more common in patients with post-treatment spasm while absent contractile response on FLIP was more common in patients without spasm (14% vs 66%, p = 0.014). The strongest predictor of post-treatment spasm was the percentage of swallows with MaxPEP ≥70 mmHg (best cut-off: ≥30%), with AUROC of 0.78. A combination of MaxPEP <70 mmHg and FLIP 60 mL pressure < 40 mmHg identified patients with lower rates of post-treatment spasm (3% overall, 0% post-PD) compared to those with values above these thresholds (33% overall, 83% post-PD)., Conclusions: High maximum PEP values, high FLIP 60 mL pressures and contractile response pattern on FLIP Panometry prior to treatment identified type II achalasia patients more likely to exhibit post-treatment spasm. Evaluating these features may guide personalized patient management., (© 2023 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Barrett's esophagus (BE) occurs in 5-15% of patients with gastroesophageal reflux disease (GERD). While acid suppressive therapy is a critical component of BE management to minimize the risk of progression to esophageal adenocarcinoma, surgical control of mechanical reflux is sometimes necessary. Magnetic sphincter augmentation (MSA) is an increasingly utilized anti-reflux surgical therapy for GERD. While the use of MSA is listed as a precaution by the United States Food and Drug Administration, there are limited data showing effective BE regression with MSA. MSA offers several advantages in BE including effective reflux control, anti-reflux barrier restoration and reduced hiatal hernia recurrence. However, careful patient selection for MSA is necessary., (© The Author(s) 2023. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background & Aims: An association of eosinophilic esophagitis (EoE) with esophageal dysmotility has been described, however, the related mechanism remains unclear. We aimed to evaluate clinical and physiologic characteristics, including esophageal distensibility, associated with secondary peristalsis in patients with EoE., Methods: A total of 199 consecutive adult patients with EoE (age, 18-78 y; 32% female) who completed a 16-cm functional luminal imaging probe (FLIP) during endoscopy were evaluated in a cross-sectional study. FLIP panometry contractile response (CR) patterns were classified as normal CR or borderline CR if antegrade contractions were present, and abnormal CRs included impaired/disordered CR, absent CR, or spastic-reactive CR. The distensibility plateau of the esophageal body and esophagogastric junction distensibility was measured with FLIP., Results: FLIP CR patterns included 68 (34%) normal CR, 65 (33%) borderline CR, 44 (22%) impaired/disordered CR, 16 (8%) absent CR, and 6 (3%) spastic-reactive CR. Compared with normal CRs, abnormal CRs more frequently had reduced esophageal distensibility (distensibility plateau <17 mm in 56% vs 32%), greater total EoE reference scores (median, 5; interquartile range [IQR], 3-6 vs median, 4; IQR, 3-5) with more severe ring scores, and a greater duration of symptoms (median, 10 y; IQR, 4-23 y vs median, 7 y; IQR, 3-15 y). Mucosal eosinophil density, however, was similar between abnormal CRs and normal CRs (median, 34 eosinophils/high-power field [hpf]; IQR, 14-60 eosinophils/hpf vs median, 25 eosinophils/hpf; IQR, 5-50 eosinophils/hpf)., Conclusions: Although normal secondary peristalsis was observed frequently in this EoE cohort, abnormal esophageal CRs were related to EoE disease severity, especially features of fibrostenosis. This study evaluating secondary peristalsis in EoE suggests that esophageal wall remodeling, rather than eosinophilic inflammatory intensity, was associated with esophageal dysmotility in EoE., (Copyright © 2022 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Competing interests The authors declare that they have no conflict of interest.

Endoscopic eradication therapy (EET) is recommended for patients with Barrett's esophagus (BE)-associated neoplasia and is effective in achieving complete eradication of intestinal metaplasia (CE-IM). However, BE that is refractory to EET, defined as partial or no improvement in dysplasia after less than or equal to 3 ablative sessions, and the development of recurrence post-EET is not uncommon. Identification of refractory BE or recurrent intestinal metaplasia should prompt esophageal physiologic testing and modification of antireflux strategy, as appropriate. In patients who ultimately fail standard EET despite optimization of reflux control, salvage EET with alternate modalities may need to be considered., Competing Interests: Disclosure S. Komanduri: Financial Disclosures: Consultant, Medtronic; Consultant, Boston Scientific; Consultant, Cook Medical; Consultant, Olympus Corp; Consultant, GI Supply; Educational Grant, Boston Scientific. V.R. Muthusamy: Consultant and research support: Boston Scientific and Medtronic; Consultant: Medivators and Interpace Diagnostics; Stockholder: Capsovision; Honoraria: Torax Medical/Ethicon. Drs D.A. Farina and A. Condon report no relevant disclosures., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background and study aims  Critically ill patients may require endoscopic retrograde cholangiopancreatography (ERCP) but performing ERCP in the intensive care unit (ICU) poses logistic and technical challenges. There are no data on ICU patients undergoing ERCP in the endoscopy suite. The primary aim of this study was to report outcomes, including safety, when ERCP in critically ill patients is performed in the endoscopy suite. Patients and methods  We queried our institutional endoscopy database to identify all ICU patients who underwent ERCP at a single academic medical center from 04/01/2010 to 11/30/2017. Only patients admitted to an ICU prior to ERCP were included. Results  Of 7,218 ERCPs performed during the study period, 260 ERCPs (3.6 %) were performed in 231 ICU patients (mean age 61y; 53 % male); nearly all ICU patient ERCPs (n = 258; 99 %) occurred in the endoscopy suite. ERCP indications included cholangitis (50 %), post-liver transplant cholestasis (15 %), and bile leak (10 %). All ERCPs were performed with anesthesiology, most with general anesthesia (60 %) and in the prone position (60 %). Most patients (73 %) had sepsis. Prior to ERCP, 17 % of patients required vasopressors; vasopressors were begun during ERCP in 4 %. The cannulation success rate was 95 % (94 % in native papillae). Adverse events occurred in 9 % (n = 23) of cases with post-ERCP pancreatitis most common. No patients died during or within 24 hours of ERCP. Mortality at 30 days was 16 %, all attributed to underlying disease. Conclusions  When advanced ventilatory and hemodynamic support is available, critically ill patients can safely and effectively undergo ERCP in the endoscopy suite., Competing Interests: Competing interests Dr. Komanduri is a consultant for Medtronic, Boston Scientific, Cook Medical, Olympus Corp, and GI Suppl and has received educational grants from Boston Scientific. Dr. Aadam is a consultant for Boston Scientific. Dr. Keswani is a consultant for Boston Scientific and Medtronic

Background and Objectives: Lymph node evaluation recommendations for extremity soft tissue sarcoma (ESTS) are absent from national guidelines. Our objectives were (1) to assess rates and predictors of nodal evaluation, and (2) to assess rates and predictors of nodal metastases., Methods: ESTS patients from the National Cancer Data Base (2000-2009) were assessed, and regression models were used to identify factors associated with nodal evaluation and metastases., Results: Of 27,536 ESTS patients, 1,924 (7%) underwent nodal evaluation, and of these, 290 (15%) had nodal metastases. Nodal evaluation was most frequently performed for rhabdomyosarcoma (15.6%), angiosarcoma (10.0%), clear cell sarcoma (39.3%), epithelioid sarcoma (28.1%), and synovial sarcoma (9.3%). On multivariable analysis, factors associated with nodal evaluation included histologic subtype, tumor size, and grade. Nodal metastasis rates were highest among patients with rhabdomyosarcoma (32.1%), angiosarcoma (24.1%), clear cell sarcoma (27.7%), and epithelioid sarcoma (31.8%). On multivariable analysis, factors associated with nodal metastases included histologic subtype, tumor size, and grade., Conclusions: Nodal evaluation rates are highest among certain expected subtypes but are generally low. However, nodal metastasis rates for many histologic subtypes in patients selected for lymph node evaluation may be higher than previously reported. Multi-institutional studies should address nodal evaluation for ESTS., (© 2014 Wiley Periodicals, Inc.)