2D Materials in Flexible Electronics: Recent Advances and Future Prospectives.

Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field.

Influence of Procedural Volume on the Outcome of Gastric Endoscopic Submucosal Dissection: A Nationwide Population-Based Study Using Administrative Data.

BACKGROUND & AIMS: Endoscopic submucosal dissection (ESD) is a well-established treatment modality for gastric neoplasms. We aimed to investigate the effect of procedural volume on the outcome of ESD for gastric cancer or adenoma. METHODS: In this population-based cohort study, patients who underwent ESD for gastric cancer or adenoma from November 2011 to December 2017 were identified using the Korean National Health Insurance Service database. Operational definitions to identify the target population and post-procedural complications were created using diagnosis and procedure codes and were validated using hospital medical record data. Outcomes included hemorrhage, perforation, pneumonia, 30-day mortality, a composite outcome comprising all of these adverse outcomes, and additional resection. Hospital volume was categorized into 3 groups based on the results of the threshold analysis: high-, medium-, low-volume centers (HVCs, MVCs, and LVCs, respectively). Inverse probability of treatment weighting analysis was applied to enhance comparability across the volume groups. RESULTS: There were 94,246 procedures performed in 88,687 patients during the study period. There were 5886 composite events including 4925 hemorrhage, 447 perforation, and 703 pneumonia cases. There were significant differences in ESD-related adverse outcomes among the 3 hospital volume categories, showing that HVCs and MVCs were associated with a lower risk of a composite outcome than LVCs (inverse probability of treatment-weighted odds ratio [OR], 0.651; 95% CI, 0.521-0.814; inverse probability of treatment-weighted OR, 0.641; 95% CI, 0.534-0.769). Similar tendencies were also shown for hemorrhage, perforation, and pneumonia; however, these were not evident for additional resection. CONCLUSIONS: Procedural volume was closely associated with clinical outcome in patients undergoing ESD for gastric cancer or adenoma.

Monolithic 3D integration of 2D materials-based electronics towards ultimate edge computing solutions.

Three-dimensional (3D) hetero-integration technology is poised to revolutionize the field of electronics by stacking functional layers vertically, thereby creating novel 3D circuity architectures with high integration density and unparalleled multifunctionality. However, the conventional 3D integration technique involves complex wafer processing and intricate interlayer wiring. Here we demonstrate monolithic 3D integration of two-dimensional, material-based artificial intelligence (AI)-processing hardware with ultimate integrability and multifunctionality. A total of six layers of transistor and memristor arrays were vertically integrated into a 3D nanosystem to perform AI tasks, by peeling and stacking of AI processing layers made from bottom-up synthesized two-dimensional materials. This fully monolithic-3D-integrated AI system substantially reduces processing time, voltage drops, latency and footprint due to its densely packed AI processing layers with dense interlayer connectivity. The successful demonstration of this monolithic-3D-integrated AI system will not only provide a material-level solution for hetero-integration of electronics, but also pave the way for unprecedented multifunctional computing hardware with ultimate parallelism.

Developing Operational Definitions Related to Helicobacter pylori Eradication Therapy.

BACKGROUND: The lack of well-established operational definitions is a major limitation of Helicobacter pylori eradication studies that use secondary databases. We aimed to develop and validate operational definitions related to H. pylori eradication therapy. METHODS: Operational definitions were developed by analyzing a nationwide H. pylori eradication registry and validated using real-world data from hospital medical records. The primary endpoint was the sensitivity of the operational definitions in identifying individuals who received H. pylori eradication therapy. The secondary endpoint was the sensitivity and specificity of the operational definition in identifying successful H. pylori eradication therapy. RESULTS: H. pylori eradication therapy was defined as a prescription for one of the following combinations: 1) proton pump inhibitor (PPI) + amoxicillin + clarithromycin, 2) PPI + amoxicillin + metronidazole, 3) PPI + metronidazole + tetracycline, 4) PPI + amoxicillin + levofloxacin, 5) PPI + amoxicillin + moxifloxacin, or 6) PPI + amoxicillin + rifabutin. In the validation set, the sensitivity of the operational definition for identifying individuals who received H. pylori eradication therapy was 99.7% and 99.8% for the first- and second-line therapies, respectively. Operational definition to determine success or failure of the H. pylori eradication therapy was developed based on a confirmatory test and the prescription of rescue therapy. The sensitivity and specificity of the operational definition for predicting successful eradication were 97.6% and 91.4%, respectively, in first-line therapy and 98.6% and 54.8%, respectively, in second-line therapy. CONCLUSION: We developed and validated operational definitions related to H. pylori eradication therapy. These definitions will help researchers perform various H. pylori eradication-related studies using secondary databases.

Establishment of Patient-Derived Gastric Cancer Organoid Model From Tissue Obtained by Endoscopic Biopsies.

Cancer organoids are three-dimensional mini-organ analogues derived from cancer tissues and have been proposed as models capable of simulating the structure and function of human organs and tissues in vitro. We sought to establish gastric cancer patient-derived organoids (PDOs) from tissues obtained by endoscopic biopsies. Gastric cancer-PDOs were successfully established and cultured from cancer tissues with gastric adenocarcinoma by endoscopic biopsies. To confirm that gastric cancer-PDOs were derived from cancer tissue, the consistency of the original cancer tissue was assessed by histopathological examination. As a result, it was confirmed that the shape and internal structure of gastric cancer-PDO were derived from the original gastric cancer cells, and the tumor specificity of gastric cancer-PDO was confirmed through Periodic acid-Schiff (PAS) and polyclonal carcinoembryonic antigen antibody staining. These results demonstrate that gastric cancer-PDO models show the characteristics of primary tumors and have potential for drug screening and providing a personalized medicine platform.

Neuronal ApoE Regulates the Cell-to-Cell Transmission of α-Synuclein.

The presence of protein inclusions, called Lewy bodies (LBs) and Lewy neurites (LNs), in the brain is the main feature of Parkinson's disease (PD). Recent evidence that the prion-like propagation of α-synuclein (α-syn), as a major component of LBs and LNs, plays an important role in the progression of PD has gained much attention, although the molecular mechanism remains unclear. In this study, we evaluated whether neuronal ApoE regulates the cell-to-cell transmission of α-syn and explored its molecular mechanism using in vitro and in vivo model systems. We demonstrate that neuronal ApoE deficiency attenuates both α-syn uptake and release by downregulating LRP-1 and LDLR expression and enhancing chaperone-mediated autophagy activity, respectively, thereby contributing to α-syn propagation. In addition, we observed that α-syn propagation was attenuated in ApoE knockout mice injected with pre-formed mouse α-syn fibrils. This study will help our understanding of the molecular mechanisms underlying α-syn propagation.

Peptide Assemblies Mimicking Chaperones for Protein Trafficking.

Although peptide assemblies have been explored extensively, the self-assembly of negatively charged peptides (NCPs) received little attention. Stimulated by the fact that acidic stretch is a common feature in the intrinsically disordered regions of histone chaperones, we explored the use of the assemblies of NCPs for trafficking histone proteins. Our results show that the peptides that contain glutamic acid (E)-repeat, at neutral or basic pH, self-assemble to form micelles in solution. Circular dichroism indicates that increasing pH favored the peptides to populate more in disordered and α helix conformations. Being innocuous to cells, the assemblies of these NCPs traffic histone 2B (H2B) to mitochondria. Structure-activity study indicates that self-assembly, proper stereochemistry, and acidic repeats are necessary for trafficking H2B. This work, as the first example of peptide assemblies for protein trafficking, illustrates a supramolecular approach for controlling cellular processes and provides insights for mimicking chaperones and controlling protein-protein interactions.

Enzyme-Instructed Self-Assembly for Cancer Therapy and Imaging.

Enzymatic reactions and self-assembly are two fundamental attributes of cells. It is not surprising that one can use enzyme-instructed self-assembly (EISA)-the integration of enzymatic transformation and molecular self-assembly-to modulate the emergent properties of supramolecular assemblies for controlling cell behaviors. The exploration of EISA for developing cancer therapy and imaging has made considerable progress over the last five years. In this Topical Review, we discuss these exciting results and the future promise of EISA. After describing several key studies to illustrate the progress of EISA in developing cancer therapy, we discuss the use of EISA for molecular imaging. Then, we give the outlook of EISA for developing supramolecular anticancer medicine that inhibits multiple hallmark capabilities of cancer.

The ratio of hydrogelator to precursor controls the enzymatic hydrogelation of a branched peptide.

Here, we report an apparently counterintuitive observation, in which a lower volume fraction of a branched peptide forms a stronger hydrogel after an enterokinase (ENTK) cleaves off the branch from the peptide. By varying the ratios of the branched peptide and ENTK and analysing the ratio of hydrogelator to precursor (H/P) in the enzymatic proteolysis reaction, our study shows that the H/P ratio controls the critical strain of the hydrogel formed, through enzymatic cleavage of the branch from the peptide. This work demonstrates that emergent properties (e.g., hydrogelation) of peptide assemblies, resulting from enzymatic noncovalent synthesis (ENS), are context-dependent, while also providing insights for developing dynamic soft materials via ENS.

Online registry for nationwide database of Helicobacter pylori eradication in Korea: Correlation of antibiotic use density with eradication success.

BACKGROUND: The Helicobacter pylori eradication rate has decreased with increasing antibiotic resistance. We conducted a prospective, nationwide, multicenter registry study to monitor the real status of H. pylori eradication therapy and to investigate the association between eradication success and antibiotic use density in Korea. MATERIALS AND METHODS: We enrolled 9318 patients undergoing H. pylori eradication therapy from 37 hospitals through "on-line database registry" from October 2010 to July 2015. Demographic data, detection methods, treatment indications, regimens, durations, compliance, adverse events, and eradication results were collected. The use of all commercially available eradication antibiotics was analyzed through the Korean National Health Insurance data of the Health Insurance Review and Assessment Service. The defined daily dose of antibiotics was used to standardize drug use comparisons. RESULTS: Finally, 6738 patients were analyzed. The overall eradication rate of first-line therapy was 71.8%. The eradication success rates were 71.7%, 86.9%, and 74.0% for standard triple therapy for 7 days, quadruple therapy, and concomitant therapy, respectively. The eradication success rate in naive patients was higher than that in those who previously underwent H. pylori eradication. Eradication success was significantly associated with younger age, female sex, and high compliance. Regional differences in eradication rates were observed. The yearly use density of clarithromycin increased statistically in seven regions across the country from 2010 to 2015. The yearly use density of amoxicillin in the Gyeongsang and Chungcheong areas was significantly increased (P < .01), whereas that of other macrolides was significantly lower in the Gyeonggi area than in other areas (P = .01). The overall use of eradication antibiotics has increased while the eradication rate steadily decreased for 5 years. However, there was no significant correlation between antibiotic use density and eradication. CONCLUSION: There was no relationship between the eradication rate and antibiotic use density in Korea.

Endoscopic closure of iatrogenic colon perforation using dual-channel endoscope with an endoloop and clips: methods and feasibility data (with videos).

BACKGROUND: Colon perforation is the most serious complication associated with colonoscopic procedures. We performed a novel purse-string suture technique to close the iatrogenic colonic perforation using dual-channel endoscope with an endoloop and clips. METHODS: Iatrogenic colon perforations developed during diagnostic colonoscopy referred to a tertiary hospital over 10 years were considered for this endoscopic closure. An endoloop was inserted through the left channel of the endoscope and placed around the defect. The first clip was placed at the proximal site of the defect through the other channel of the endoscope, and the endoloop was anchored on the mucosa around the defect. Then, subsequent clips were placed next to previous clips and the endoloop was fixed. After the defect was encircled by the endoloop and clips, the rim of the opening was approximated by fastening the endoloop with a purse-string technique. RESULTS: A total of 8 patients were admitted to our hospital because of iatrogenic colon perforations during diagnostic colonoscopy. Of these, 2 underwent laparoscopic surgery and 6 underwent endoscopic closure by this novel purse-string suture technique. The estimated diameters of the perforations were 20 mm. All cases were successfully treated in the endoscopy unit without sedation or general anesthesia, and recovered without any complication or subsequent operation. Abdominal pain had nearly resolved within 3 days after the procedure in all patients, and only mild peritonitis was observed. CONCLUSIONS: Iatrogenic colon perforation can be treated with a purse-string suture technique using dual-channel endoscope with an endoloop and clips. This technique can be useful for relatively large colon perforations associated with diagnostic colonoscopy.

Minimization of Wound With the Assistance of a Needle Grasper in Single-Incision Laparoscopic Appendectomy.

Background. Technical difficulties and pain from large wounds have prevented the widespread use of single-incision laparoscopic appendectomy (SILA). This study aimed to evaluate the efficacy of our newly developed needle grasper (Endo Relief)-assisted SILA (NASILA). Methods. For NASILA, about a 12-mm umbilical incision was made, and a glove port was introduced. A needle grasper was then introduced through a 2.5-mm wound on the suprapubic area. For SILA, a 2.5-cm transumbilical wound was made. The medical records of patients who underwent SILA or NASILA from June 2017 to September 2017 were retrospectively reviewed. Operative and short-term postoperative outcomes and results of telephone interviews for scars were compared. Results. A total of 49 patients in the SILA group (male: 40.8%) and 12 in the NASILA group (male: 50.0%) were included. Appendicitis status (not perforated:perforated without abscess:perforated with abscess) was significantly different between the 2 groups (SILA vs NASILA, 30:18:1 vs 4:6:2, P = .027). Additional trocars were inserted in 9 patients (18.4%) of the SILA group. The operative time was significantly shorter (43.3 ± 33.6 vs 54.1 ± 15.6 minutes, P = .012), and the highest numerical pain intensity score during the first 24 hours after surgery was significantly lower (2.4 ± 0.7 vs 3.0 ± 0.9, P = .038) in the NASILA group than in the SILA group. Hospital stay, postoperative complications, and complaint of scar were not significantly different between the 2 groups. Conclusions. NASILA was not inferior to SILA regarding cosmetic results. Operative convenience is higher in NASILA than in SILA, and the smaller surgical wound in NASILA minimizes postoperative pain.

Salt-Induced, Continuous Deposition of Supramolecular Iron(III)-Tannic Acid Complex.

One-step assembly of iron(III)-tannic acid (Fe3+-TA) complex forms nanothin (∼10 nm) films on various substrates within minutes. In this deposition scheme, however, the film does not grow continuously over time even though Fe3+-TA complex is still abundant in the coating solution. In this paper, we report that the salt addition dramatically changes the one-off coating characteristic to continuous one, and each salt has its optimum concentration ( CMFT) that produces maximum film thickness. For detailed investigation of the salt effects, we employed various salts, including LiCl, NaCl, KCl, CaCl2, SrCl2, BaCl2, NaBr, and NaNO3, and found that only cations played an important role in the continuous deposition of the Fe3+-TA complex, with smaller CMFT values for the cations of higher valency and larger size. On the basis of the results, we suggested that the positively charged cations screened the negative surface charges of Fe3+-TA complex particles, leading to coagulation and continuous deposition, further supported by the ζ-potential measurement and time-resolved dynamic light-scattering analysis.

The Fatty Liver Index: A Simple and Accurate Predictor of Colorectal Adenoma in an Average-Risk Population.

BACKGROUND: Nonalcoholic fatty liver disease, the hepatic manifestation of metabolic syndrome, is associated with increased risk of colorectal adenoma, a precursor of colorectal cancer. Because nonalcoholic fatty liver disease and colorectal adenoma share many common risk factors of metabolic syndrome, the association between these 2 pathological findings has been investigated in multiple studies, but the results have been conflicting. OBJECTIVE: The present study aimed to assess the relationship between the fatty liver index, a predictor of nonalcoholic fatty liver disease, and the prevalence of colorectal adenomas. DESIGN: This is a retrospective observational study. SETTINGS: This study was conducted at a single expert center. PATIENTS: A total of 2976 consecutive subjects over 40 years of age undergoing routine checkups including abdominal ultrasonography and colonoscopy at Chung-Ang University Hospital Health Care Center were included. MAIN OUTCOME MEASURES: The primary outcome measured was the prevalence of colorectal adenomas according to fatty liver index. RESULTS: Among these subjects, 932 (31.3%) had colorectal adenoma, 691 (23.2%) had metabolic syndrome, and 1512 (50.8%) had fatty liver on ultrasonography. In multivariate analysis, fatty liver index ≥30 was associated with an increased risk of colorectal adenoma (OR, 1.269; 95% CI, 1.06-1.49; p = 0.008). The fatty liver index-high group (fatty liver index ≥30) had more colorectal adenomas and more advanced colorectal adenomas than the fatty liver index-low group (fatty liver index <30) (p < 0.001 and p = 0.042). The prevalence of colorectal adenomas increased with increasing quartile of fatty liver index (p < 0.05). LIMITATIONS: The study was limited by a relatively healthy Asian population. CONCLUSION: The high fatty liver index may be a useful predictor of colorectal adenoma. See Video Abstract at http://links.lww.com/DCR/A478.

Abdominal Visceral to Subcutaneous Adipose Tissue Ratio Is Associated with Increased Risk of Erosive Esophagitis.

BACKGROUND: To investigate the association between abdominal fat distribution represented by the visceral fat area (VFA) to subcutaneous fat area (SFA) ratio, and erosive esophagitis (EE). METHODS: Seven hundred and twenty-eight participants aged >40 years underwent physical examination, blood tests, esophagogastroduodenoscopy, and abdominal computer tomography at Chung-Ang University Hospital from 2007 to 2012. RESULTS: Of 728 subjects, 65 (8.9%) had EE. The EE patients had higher body mass index, metabolic syndrome prevalence, triglyceride levels, and blood pressure (P < 0.05). The mean VFA/SFA ratio was higher in the EE group than in the non-EE group (1.30 vs. 0.92, P < 0.001). The predominance of EE in the group with higher VFA/SFA ratio was higher than in the group with lower VFA/SFA ratio (P < 0.001). A VFA/SFA ratio ≥1.165 had good accuracy to predict EE (area under the receiver-operating characteristic curve, 0.643). The VFA/SFA ratio and visceral fat volume were positively correlated with the severity of EE (P = 0.002), and a VFA/SFA ratio ≥1.165 was strongly correlated with the severity of EE (P < 0.001). CONCLUSION: The high VFA/SFA ratio can be a useful clinical predictor of EE.

Preoperative Body Mass Index May Determine the Prognosis of Advanced Gastric Cancer.

Radical gastrectomy followed by adjuvant chemotherapy for advanced gastric cancer causes serious nutritional impairment. Our study evaluated the clinical impact of body mass index (BMI) on the long-term outcomes of advanced gastric cancer (stage II and III). We analyzed 211 cases of stage II and III gastric cancer between January 2005 and December 2010 at Chung-Ang University Hospital, Seoul, Korea. Patients were divided into four groups according to BMI: underweight, normal, overweight, and obese. In addition, we divided patients into two groups: BMI-High (BMI ≥ 23 kg/m2) vs. BMI-Low (BMI < 23 kg/m2). We assessed age, sex, tumor location, lymph node (LN) involvement, operation method, initial cancer stage, recurrence, and survival between the two groups. There was significant difference in overall survival (OS) between the underweight group and the other groups (P = 0.005). The survival of the BMI-High group was better than that of the BMI-Low group. The rate of cancer-related death in the BMI-High group was significantly lower than that in the BMI-Low group (cancer-related death: BMI-Low 27% vs. BMI-High 12.6%, P = 0.022). Our findings suggest that preoperative BMI may have an influence on the long-term outcomes of advanced gastric cancer after radical surgery and chemotherapy.

Online Registry for Nationwide Database of Current Trend of Helicobacter pylori Eradication in Korea: Interim Analysis.

Eradication of Helicobacter pylori using first-line therapy is becoming less effective. Subjects who had been treated for H. pylori infection were prospectively enrolled through an on-line database registry from October 2010 to December 2012. Demographic data, detection methods, treatment indication, regimens, durations, compliance, adverse events, and eradication results for H. pylori infection were collected. Data of 3,700 patients from 34 hospitals were analyzed. The overall eradication rate of the first-line therapy was 73.0%. Eradication failure was significantly associated with old age, concomitant medication, and comorbidity. Regional differences in eradication rates were observed. The most common first-line therapy was proton pump inhibitor-based triple therapy (standard triple therapy, STT) for 7 days (86.8%). The eradication rates varied with regimens, being 73% in STT, 81.8% in bismuth-based quadruple therapy, 100% in sequential therapy, and 90.3% in concomitant therapy. The eradication rate in treatment-naïve patients was higher than that in patients previously treated for H. pylori infection (73.8% vs. 58.5%, P < 0.001). The overall eradication rate for second-line therapy was 84.3%. There was no statistical difference in eradication rates among various regimens. H. pylori eradication rate using STT is decreasing in Korea and has become sub-optimal, suggesting the need for alternative regimens to improve the efficacy of first-line therapy for H. pylori infection.

Cytocompatible Polymer Grafting from Individual Living Cells by Atom-Transfer Radical Polymerization.

A cytocompatible method of surface-initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI-ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine-based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material-independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical-scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell-division studies. This work will provide a strategic approach to the generation of living cell-polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy.

Nonfaradaic nanoporous electrochemistry for conductometry at high electrolyte concentration.

Nanoporous electrified surfaces create a unique nonfaradaic electrochemical behavior that is sensitively influenced by pore size, morphology, ionic strength, and electric field modulation. Here, we report the contributions of ion concentration and applied ac frequency to the electrode impedance through an electrical double layer overlap and ion transport along the nanopores. Nanoporous Pt with uniform pore size and geometry (L2-ePt) responded more sensitively to conductivity changes in aqueous solutions than Pt black with poor uniformity despite similar real surface areas and enabled the previously difficult quantitative conductometry measurements at high electrolyte concentrations. The nanopores of L2-ePt were more effective in reducing the electrode impedance and exhibited superior linear responses to not only flat Pt but also Pt black, leading to successful conductometric detection in ion chromatography without ion suppressors and at high ionic strengths.

Comparison of the efficacy of 4- and 8-week lansoprazole treatment for ESD-induced gastric ulcers: a randomized, prospective, controlled study.

BACKGROUND: Although endoscopic submucosal dissection (ESD) is widely used to treat gastric neoplasms, there is no consensus for the optimal treatment for ESD-induced ulcers. We compared efficacy between 4 and 8 weeks of lansoprazole treatment for iatrogenic gastric ulcers that developed after ESD. METHODS: Eighty-four patients who were diagnosed with gastric adenoma or early gastric cancer were enrolled and randomly assigned to treatment with lansoprazole (30 mg/day) for 4 or 8 weeks. Eight weeks after ESD, we conducted follow-up endoscopy to compare ulcer stage and ulcer reduction ratio (dividing the ulcer dimension at 8 weeks by the initial ulcer dimension) between the two groups. RESULTS: From the 84 patients, 69 patients were included in the final analysis, with 34 in the 4-week group and 35 in the 8-week group. Eight weeks after ESD, there were no significant difference observed between the two groups in terms of the ulcer stage (68 % in the scar stage in the 4-week group vs. 69 % in the 8-week group, P = 0.93) or the ulcer reduction ratio (0.0081 ± 0.015 in the 4-week group vs. 0.0037 ± 0.008 in the 8-week group, P = 0.15). Also, in the subgroup analysis among the patients with large ulcers (>30 mm), those parameters were not different. CONCLUSIONS: For ESD-induced gastric ulcers, treatment with lansoprazole for 4 weeks was as effective as treatment for 8 weeks. Considering cost-effectiveness, proton pump inhibitor therapy for 4 weeks may be sufficient for ESD-induced gastric ulcers.