The Experts below are selected from a list of 51150 Experts worldwide ranked by ideXlab platform
Erik B. Wilson - One of the best experts on this subject based on the ideXlab platform.
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Foreign Material Erosion after laparoscopic Roux-en-Y gastric bypass: findings and treatment.
Surgical endoscopy, 2007Co-Authors: K. Jastrow, B. Clapp, Lillian S. Kao, Connie Klein, Terry Scarborough, Erik B. WilsonAbstract:Background Patients after laparoscopic Roux-en-Y gastric bypass (LRYGB) can have nonspecific, upper gastrointestinal (UGI) complaints. During postoperative endoscopy, we have noted the Erosion of nondissolvable Material, such as Peri-Strips® or silk sutures, into the gastric pouch. This study reports the incidence and presentation of foreign Material Erosion into the gastric pouch after a LRYGB and the outcome after therapeutic endoscopy.
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foreign Material Erosion after laparoscopic roux en y gastric bypass findings and treatment
Surgical Endoscopy and Other Interventional Techniques, 2007Co-Authors: K. Jastrow, B. Clapp, Lillian S. Kao, Connie Klein, Terry Scarborough, Erik B. WilsonAbstract:Patients after laparoscopic Roux-en-Y gastric bypass (LRYGB) can have nonspecific, upper gastrointestinal (UGI) complaints. During postoperative endoscopy, we have noted the Erosion of nondissolvable Material, such as Peri-Strips® or silk sutures, into the gastric pouch. This study reports the incidence and presentation of foreign Material Erosion into the gastric pouch after a LRYGB and the outcome after therapeutic endoscopy. From a prospective LRYGB database, postoperative endoscopies from February 2002 to June 2005 that found foreign Material in the gastric pouch were reviewed. Presenting symptoms, time until endoscopy, and patient outcomes were evaluated. A therapeutic endoscopy was performed by using endo-shears and biopsy forceps to remove the foreign Material. A total of 23 patients underwent 29 therapeutic endoscopies. From February 2002 to November 2004, 208 LRYGB were performed using silk suture for the outer layer of the gastrojejunostomy, and 21 patients (10%) had silk suture found on endoscopy. Peri-Strips were used from February 2002 to December 2003 (n = 153) and 6 patients (4%) had Erosions. Since converting to Vicryl suture and Seamguard®, we have had 173 and 228 patients, respectively, without pouch Erosion. The most common presenting symptom was abdominal pain (n = 15, 65%). Other symptoms included nausea (n = 13, 57%), vomiting (n = 12, 52%), dysphagia (n = 5, 22%), and melena (n = 3, 13%). Foreign Material was found by a mean of 34 weeks. Of 29 therapeutic endoscopies, 20 resulted in resolution of symptoms (69%), 4 led to improvements (14%), and 5 had no effect (17%). There were no endoscopic complications and no anastomotic leaks. Nonabsorbable Material used during a LRYGB can migrate into the gastric pouch and cause UGI complaints. A therapeutic endoscopy will resolve most UGI symptoms. Using absorbable Material in the creation of the gastric pouch and the gastrojejunostomy will avoid foreign Material Erosion.
R Ding - One of the best experts on this subject based on the ideXlab platform.
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real time monitoring of Material Erosion and deposition for the first wall using quartz crystal microbalance in east
Nuclear materials and energy, 2021Co-Authors: R Ding, Y Zhang, J Peng, H Xie, Rong Yan, J ChenAbstract:Abstract Two new quartz crystal microbalance (QMB) systems have been installed at different locations in the mid-plane of EAST to measure Erosion and deposition of the first wall Materials. The two QMBs with different distances from the plasma show complex and distinct Erosion and deposition behavior. The QMB in the mid-plane H port closer to the plasma shows a relatively higher net Erosion result with an average Erosion rate of 1.34 ng/(cm2s). The normal discharges mainly contribute to the total net Erosion and the maximum Erosion amount reaches up to 110 ng/cm2. Contrarily, a slight net deposition of 0.11 ng/(cm2s) is obtained for the QMB in the mid-plane G port further away from the plasma and the Erosion and deposition amount of most discharges are much lower due to lower particle flux. The disruptive discharges lead to a total net deposition rate of 0.48 ng/(cm2s). Measurement results by the QMBs are demonstrated by a good agreement with the post-mortem analysis by Rutherford Backscattering Spectrometry (RBS).
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development of a quartz crystal microbalance diagnostic for measuring Material Erosion and deposition on the first wall in east
Review of Scientific Instruments, 2020Co-Authors: Y Zhang, R Ding, J Peng, H Xie, J ChenAbstract:A quartz crystal microbalance (QMB) diagnostic system has been established in Experimental Advanced Superconducting Tokamak (EAST) for real-time and in situ measurements of Erosion and deposition rates of plasma-facing Materials at the first wall. A ∼70 nm aluminum (Al) film has been coated on the QMB crystal surface to measure the Erosion rate by charge exchange neutral particles. Dual sensors of the QMB system have been used with a closed sensor for reference. The stability and light sensitivity of the QMB system have been tested in the lab, demonstrating its feasibility on the application of EAST experiments. The QMB system with cooling water has been successfully applied in the 2018 EAST campaign. The net Erosion thickness measured by the QMB has been well validated by thickness measurements using the Rutherford backscattering spectrometry. The developed QMB systems can help us to understand the physics processes of Material Erosion and deposition at main chamber walls for long pulse operations in EAST.
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development of a time of flight low energy neutral particle analyzer for east tokamak
Review of Scientific Instruments, 2018Co-Authors: R Ding, Lin Mu, J. L. Chen, Shenghu LiAbstract:To understand the Erosion effect of neutral particles on the first wall, a low energy neutral particle analyzer (LENPA), based on the time-of-flight method, has been developed for the Experimental Advanced Superconducting Tokamak (EAST). The LENPA to be installed in the EAST mid-plane mainly consists of a chopper sub-system, a 3 m long flight tube, two sets of detector assemblies, and data acquisition and processing, vacuum, power supply, and control sub-systems. The neutral outflux is gated in bunches of 1 μs time scale by a slotted rotating disc which is driven by a vacuum compatible motor modified from a turbomolecular pump. A He–Ne laser beam is projected through the disc slit to record the instants of chopper slits opening with an avalanche photodiode module. An on-axis electron multiplier detects chopped neutrals, and a central perforated Cu–Be plate is employed to channel the emitted secondary electrons into an off-axis electron multiplier. The radiation peaks of on-axis electron multiplier caused by UV photons projected through the central hole of the Cu–Be plate provide an alternative way to record the chopper slits’ opening time. With an additional 4 TB fast memory card, 1 GS/s sampling rate has been realized by using a GaGe acquisition card continuously. The LENPA data from the EAST together with neutral particle Material Erosion experiments will be used to benchmark the simulation results for better predictions on future fusion reactors, such as ITER and China Fusion Engineering Test Reactor (CFETR).To understand the Erosion effect of neutral particles on the first wall, a low energy neutral particle analyzer (LENPA), based on the time-of-flight method, has been developed for the Experimental Advanced Superconducting Tokamak (EAST). The LENPA to be installed in the EAST mid-plane mainly consists of a chopper sub-system, a 3 m long flight tube, two sets of detector assemblies, and data acquisition and processing, vacuum, power supply, and control sub-systems. The neutral outflux is gated in bunches of 1 μs time scale by a slotted rotating disc which is driven by a vacuum compatible motor modified from a turbomolecular pump. A He–Ne laser beam is projected through the disc slit to record the instants of chopper slits opening with an avalanche photodiode module. An on-axis electron multiplier detects chopped neutrals, and a central perforated Cu–Be plate is employed to channel the emitted secondary electrons into an off-axis electron multiplier. The radiation peaks of on-axis electron multiplier caused ...
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advances in understanding of high z Material Erosion and re deposition in low z wall environment in diii d
Nuclear Fusion, 2017Co-Authors: S Brezinsek, R Ding, D L Rudakov, P C Stangeby, W R Wampler, T Abrams, A R Briesemeister, I BykovAbstract:Dedicated DIII-D experiments coupled with modeling reveal that the net Erosion rate of high-Z Materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z Material Erosion. The net Erosion rate of high-Z Materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net Erosion can be significantly suppressed by reducing the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net Erosion rate of high-Z Materials. Both DIII-D experiments and modeling show that local 13CH4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E × B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net Erosion rate by plasma perturbation. In H-mode plasmas, the measured inter-ELM W Erosion rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.
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high z Material Erosion and its control in diii d carbon divertor
Nuclear materials and energy, 2017Co-Authors: S Brezinsek, R Ding, D L Rudakov, P C Stangeby, W R Wampler, T Abrams, A R Briesemeister, I Bykov, V S ChanAbstract:Abstract As High-Z Materials will likely be used as plasma-facing components (PFCs) in future fusion devices, the Erosion of high-Z Materials is a key issue for high-power, long pulse operation. High-Z Material Erosion and redeposition have been studied using tungsten and molybdenum coated samples exposed in well-diagnosed DIII-D divertor plasma discharges. By coupling dedicated experiments and modelling using the 3D Monte Carlo code ERO, the roles of sheath potential and background carbon impurities in determining high-Z Material Erosion are identified. Different methods suggested by modelling have been investigated to control high-Z Material Erosion in DIII-D experiments. The Erosion of Mo and W is found to be strongly suppressed by local injection of methane and deuterium gases. The 13 C deposition resulting from local 13 CH 4 injection also provides information on radial transport due to E × B drifts and cross field diffusion. Finally, D 2 gas puffing is found to cause local plasma perturbation, suppressing W Erosion because of the lower effective sputtering yield of W at lower plasma temperature and for higher carbon concentration in the mixed surface layer.
K. Jastrow - One of the best experts on this subject based on the ideXlab platform.
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Foreign Material Erosion after laparoscopic Roux-en-Y gastric bypass: findings and treatment.
Surgical endoscopy, 2007Co-Authors: K. Jastrow, B. Clapp, Lillian S. Kao, Connie Klein, Terry Scarborough, Erik B. WilsonAbstract:Background Patients after laparoscopic Roux-en-Y gastric bypass (LRYGB) can have nonspecific, upper gastrointestinal (UGI) complaints. During postoperative endoscopy, we have noted the Erosion of nondissolvable Material, such as Peri-Strips® or silk sutures, into the gastric pouch. This study reports the incidence and presentation of foreign Material Erosion into the gastric pouch after a LRYGB and the outcome after therapeutic endoscopy.
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foreign Material Erosion after laparoscopic roux en y gastric bypass findings and treatment
Surgical Endoscopy and Other Interventional Techniques, 2007Co-Authors: K. Jastrow, B. Clapp, Lillian S. Kao, Connie Klein, Terry Scarborough, Erik B. WilsonAbstract:Patients after laparoscopic Roux-en-Y gastric bypass (LRYGB) can have nonspecific, upper gastrointestinal (UGI) complaints. During postoperative endoscopy, we have noted the Erosion of nondissolvable Material, such as Peri-Strips® or silk sutures, into the gastric pouch. This study reports the incidence and presentation of foreign Material Erosion into the gastric pouch after a LRYGB and the outcome after therapeutic endoscopy. From a prospective LRYGB database, postoperative endoscopies from February 2002 to June 2005 that found foreign Material in the gastric pouch were reviewed. Presenting symptoms, time until endoscopy, and patient outcomes were evaluated. A therapeutic endoscopy was performed by using endo-shears and biopsy forceps to remove the foreign Material. A total of 23 patients underwent 29 therapeutic endoscopies. From February 2002 to November 2004, 208 LRYGB were performed using silk suture for the outer layer of the gastrojejunostomy, and 21 patients (10%) had silk suture found on endoscopy. Peri-Strips were used from February 2002 to December 2003 (n = 153) and 6 patients (4%) had Erosions. Since converting to Vicryl suture and Seamguard®, we have had 173 and 228 patients, respectively, without pouch Erosion. The most common presenting symptom was abdominal pain (n = 15, 65%). Other symptoms included nausea (n = 13, 57%), vomiting (n = 12, 52%), dysphagia (n = 5, 22%), and melena (n = 3, 13%). Foreign Material was found by a mean of 34 weeks. Of 29 therapeutic endoscopies, 20 resulted in resolution of symptoms (69%), 4 led to improvements (14%), and 5 had no effect (17%). There were no endoscopic complications and no anastomotic leaks. Nonabsorbable Material used during a LRYGB can migrate into the gastric pouch and cause UGI complaints. A therapeutic endoscopy will resolve most UGI symptoms. Using absorbable Material in the creation of the gastric pouch and the gastrojejunostomy will avoid foreign Material Erosion.
S Brezinsek - One of the best experts on this subject based on the ideXlab platform.
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quantitative analysis of elemental depth on wendelstein 7 x divertor baffle screws by picosecond laser induced breakdown spectroscopy
Spectrochimica Acta Part B: Atomic Spectroscopy, 2019Co-Authors: J Oelmann, S Brezinsek, M Rasinski, C P Dhard, Ralf Konig, Y Liang, Hongbin Ding, Christian LinsmeierAbstract:Abstract Analysis of elemental distributions in plasma-facing components (PFCs) is vital for the study of Material Erosion, deposition, and fuel retention in Wendelstein 7-X (W7-X) stellarator operating in full 3D geometry. In this work, we report the results on the application of picosecond laser-induced breakdown spectroscopy (ps-LIBS) combined with laser-induced ablation quadrupole mass spectrometry (LIA-QMS) to quantitatively investigate the elemental depth distribution and fuel retention on the screws PFCs from the divertor baffle of W7-X. Depth profiles of H, C, Ti and Mo intensities on the screws with specific multilayer structures have been achieved by LIBS combined with LIA-QMS. A linear correlation approach has been applied for identifying the interface between the C layer and the Ti layer and shows that a laser ablation rate of (82.9 ± 0.9) nm/shot can be achieved on C layer thickness measurement by a laser energy density of 6.5 J/cm2. Moreover, quantitative H retention content on the surface of the screws with stellarator discharge plasma exposure is approximately 1.1 × 1021 atoms/m2 which is higher than approximately 3.5 × 1020 atoms/m2 on the surface of the new screw without plasma exposure. The studies well demonstrate the ability to determine elementary resolved layer thicknesses and H retention measurements by depth analysis of LIBS on PFCs exposed in W7-X.
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advances in understanding of high z Material Erosion and re deposition in low z wall environment in diii d
Nuclear Fusion, 2017Co-Authors: S Brezinsek, R Ding, D L Rudakov, P C Stangeby, W R Wampler, T Abrams, A R Briesemeister, I BykovAbstract:Dedicated DIII-D experiments coupled with modeling reveal that the net Erosion rate of high-Z Materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z Material Erosion. The net Erosion rate of high-Z Materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net Erosion can be significantly suppressed by reducing the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net Erosion rate of high-Z Materials. Both DIII-D experiments and modeling show that local 13CH4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E × B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net Erosion rate by plasma perturbation. In H-mode plasmas, the measured inter-ELM W Erosion rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.
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high z Material Erosion and its control in diii d carbon divertor
Nuclear materials and energy, 2017Co-Authors: S Brezinsek, R Ding, D L Rudakov, P C Stangeby, W R Wampler, T Abrams, A R Briesemeister, I Bykov, V S ChanAbstract:Abstract As High-Z Materials will likely be used as plasma-facing components (PFCs) in future fusion devices, the Erosion of high-Z Materials is a key issue for high-power, long pulse operation. High-Z Material Erosion and redeposition have been studied using tungsten and molybdenum coated samples exposed in well-diagnosed DIII-D divertor plasma discharges. By coupling dedicated experiments and modelling using the 3D Monte Carlo code ERO, the roles of sheath potential and background carbon impurities in determining high-Z Material Erosion are identified. Different methods suggested by modelling have been investigated to control high-Z Material Erosion in DIII-D experiments. The Erosion of Mo and W is found to be strongly suppressed by local injection of methane and deuterium gases. The 13 C deposition resulting from local 13 CH 4 injection also provides information on radial transport due to E × B drifts and cross field diffusion. Finally, D 2 gas puffing is found to cause local plasma perturbation, suppressing W Erosion because of the lower effective sputtering yield of W at lower plasma temperature and for higher carbon concentration in the mixed surface layer.
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plasma surface interaction in the be w environment conclusions drawn from the jet ilw for iter
Journal of Nuclear Materials, 2015Co-Authors: S BrezinsekAbstract:Abstract The JET ITER-Like Wall experiment (JET-ILW) provides an ideal test bed to investigate plasma-surface interaction (PSI) and plasma operation with the ITER plasma-facing Material selection employing beryllium in the main chamber and tungsten in the divertor. The main PSI processes: Material Erosion and migration, (b) fuel recycling and retention, (c) impurity concentration and radiation have be1en studied and compared between JET-C and JET-ILW. The current physics understanding of these key processes in the JET-ILW revealed that both interpretation of previously obtained carbon results (JET-C) and predictions to ITER need to be revisited. The impact of the first-wall Material on the plasma was underestimated. Main observations are: (a) low primary Erosion source in H-mode plasmas and reduction of the Material migration from the main chamber to the divertor ( factor 7 ) as well as within the divertor from plasma-facing to remote areas ( factor 30 - 50 ). The energetic threshold for beryllium sputtering minimises the primary Erosion source and inhibits multi-step re-Erosion in the divertor. The physical sputtering yield of tungsten is low as 10 - 5 and determined by beryllium ions. (b) Reduction of the long-term fuel retention ( factor 10 - 20 ) in JET-ILW with respect to JET-C. The remaining retention is caused by implantation and co-deposition with beryllium and residual impurities. Outgassing has gained importance and impacts on the recycling properties of beryllium and tungsten. (c) The low effective plasma charge ( Z eff = 1.2 ) and low radiation capability of beryllium reveal the bare deuterium plasma physics. Moderate nitrogen seeding, reaching Z eff = 1.6 , restores in particular the confinement and the L-H threshold behaviour. ITER-compatible divertor conditions with stable semi-detachment were obtained owing to a higher density limit with ILW. Overall JET demonstrated successful plasma operation in the Be/W Material combination and confirms its advantageous PSI behaviour and gives strong support to the ITER Material selection.
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quantitative modeling of fuel retention in the jet c and jet ilw wall configurations by walldyn and predictions for iter
Journal of Nuclear Materials, 2015Co-Authors: K Schmid, K Krieger, Steve Lisgo, S Brezinsek, G Meisl, Jet Efda ContributorsAbstract:Abstract The hydrogenic fuel retention in ITER will be dominated by co-deposition. Therefore predictions of retention in ITER require a global model of migration of low-Z (Be, C) impurities and their co-deposition with hydrogenic species. To track the global Material Erosion/deposition balance and the resulting formation of mixed Material layers the WallDYN code has been developed. This paper describes the application of WallDYN to the interpretation of results on deposition and co-deposition in JET experiments both in the ITER like wall (ILW) and full carbon configuration. The calculations show qualitative agreement with the Be deposition patterns determined from post-campaign wall tile analysis. The calculated retention results for C and Be first wall configurations even show quantitative agreement with experimental gas balance measurements when long term outgassing is taken into account. Applying WallDYN to ITER for different first wall and plasma configurations shows that for the current (Be + W only) Material choice, retention will not limit ITER operation whereas C would increase retention by factors 10–100, leading to unacceptably high fuel retention by co-deposition.
Terry Scarborough - One of the best experts on this subject based on the ideXlab platform.
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Foreign Material Erosion after laparoscopic Roux-en-Y gastric bypass: findings and treatment.
Surgical endoscopy, 2007Co-Authors: K. Jastrow, B. Clapp, Lillian S. Kao, Connie Klein, Terry Scarborough, Erik B. WilsonAbstract:Background Patients after laparoscopic Roux-en-Y gastric bypass (LRYGB) can have nonspecific, upper gastrointestinal (UGI) complaints. During postoperative endoscopy, we have noted the Erosion of nondissolvable Material, such as Peri-Strips® or silk sutures, into the gastric pouch. This study reports the incidence and presentation of foreign Material Erosion into the gastric pouch after a LRYGB and the outcome after therapeutic endoscopy.
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foreign Material Erosion after laparoscopic roux en y gastric bypass findings and treatment
Surgical Endoscopy and Other Interventional Techniques, 2007Co-Authors: K. Jastrow, B. Clapp, Lillian S. Kao, Connie Klein, Terry Scarborough, Erik B. WilsonAbstract:Patients after laparoscopic Roux-en-Y gastric bypass (LRYGB) can have nonspecific, upper gastrointestinal (UGI) complaints. During postoperative endoscopy, we have noted the Erosion of nondissolvable Material, such as Peri-Strips® or silk sutures, into the gastric pouch. This study reports the incidence and presentation of foreign Material Erosion into the gastric pouch after a LRYGB and the outcome after therapeutic endoscopy. From a prospective LRYGB database, postoperative endoscopies from February 2002 to June 2005 that found foreign Material in the gastric pouch were reviewed. Presenting symptoms, time until endoscopy, and patient outcomes were evaluated. A therapeutic endoscopy was performed by using endo-shears and biopsy forceps to remove the foreign Material. A total of 23 patients underwent 29 therapeutic endoscopies. From February 2002 to November 2004, 208 LRYGB were performed using silk suture for the outer layer of the gastrojejunostomy, and 21 patients (10%) had silk suture found on endoscopy. Peri-Strips were used from February 2002 to December 2003 (n = 153) and 6 patients (4%) had Erosions. Since converting to Vicryl suture and Seamguard®, we have had 173 and 228 patients, respectively, without pouch Erosion. The most common presenting symptom was abdominal pain (n = 15, 65%). Other symptoms included nausea (n = 13, 57%), vomiting (n = 12, 52%), dysphagia (n = 5, 22%), and melena (n = 3, 13%). Foreign Material was found by a mean of 34 weeks. Of 29 therapeutic endoscopies, 20 resulted in resolution of symptoms (69%), 4 led to improvements (14%), and 5 had no effect (17%). There were no endoscopic complications and no anastomotic leaks. Nonabsorbable Material used during a LRYGB can migrate into the gastric pouch and cause UGI complaints. A therapeutic endoscopy will resolve most UGI symptoms. Using absorbable Material in the creation of the gastric pouch and the gastrojejunostomy will avoid foreign Material Erosion.