Electrochemomechanical failure in layered oxide cathodes caused by rotational stacking faults.

Electrochemomechanical degradation is one of the most common causes of capacity deterioration in high-energy-density cathodes, particularly intercalation-based layered oxides. Here we reveal the presence of rotational stacking faults (RSFs) in layered lithium transition-metal oxides, arising from specific stacking sequences at different angles, and demonstrate their critical role in determining structural/electrochemical stability. Our combined experiments and calculations show that RSFs facilitate oxygen dimerization and transition-metal migration in layered oxides, fostering microcrack nucleation/propagation concurrently with cumulative electrochemomechanical degradation on cycling. We further show that thermal defect annihilation as a potential solution can suppress RSFs, reducing microcracks and enhancing cyclability in lithium-rich layered cathodes. The common but previously overlooked occurrence of RSFs suggests a new synthesis guideline of high-energy-density layered oxide cathodes.

Versatile Redox-Active Organic Materials for Rechargeable Energy Storage.

With the ever-increasing demand on energy storage systems and subsequent mass production, there is an urgent need for the development of batteries with not only improved electrochemical performance but also better sustainability-related features such as environmental friendliness and low production cost. To date, transition metals that are sparse have been centrally employed in energy storage devices ranging from portable lithium ion batteries (e.g., cobalt and nickel) to large-scale redox flow batteries (e.g., vanadium). Toward the sustainable battery chemistry, there are ongoing efforts to replace the transition metal-based electrode materials in these systems to redox-active organic materials (ROMs). Most ROMs are composed of the earth abundant elements (e.g., carbon, nitrogen, oxygen, sulfur), thus are less restrained by the resource, and their production does not require high-energy consuming processes. Furthermore, the structural diversity and chemical tunability of organic compounds make them more attractive for the versatile design of future energy storage systems. Accordingly, the timely development of high-performance ROM-based electrodes would expedite the shift from the current resource-limited battery chemistry to more sustainable energy solutions.In this Account, we provide an overview of the endeavors to employ and develop ROMs as high-performance active materials for various battery systems. Diverse approaches will be introduced starting from the new ROM design mimicking the energy carrying molecules in biological metabolism to the chemical modifications to tailor the properties for specific battery systems. The molecular redesign of ROM, for example, can be carried out by substituting heteroatoms in the redox center, which leads to the enhancement of the redox potential by the inductive effect. Or, tailoring the ROM molecule by removing redox-inactive functionals results in a reduced molecular weight, thereby an increased specific capacity. The intrinsic limitations of ROMs, such as the low electrical conductivity and the dissolving nature, have been under extensive scrutiny; however, they can be partly addressed through efforts including intermolecular fusion and/or nanoscale hybridization with a conducting scaffold. On the other hand, this problematic dissolving nature of ROMs makes them appealing for some new battery configurations such as redox flow batteries that employ the liquid-state active materials. The high solubility and the stability of the ROM were found to be beneficial in attaining the enhanced energy density and the cycle stability of flow batteries, which could be further optimized by the chemical modifications of ROMs. Besides the role of active materials, the redox activity of ROMs has also enabled their use as catalysts to promote the electrode reaction in metal-air batteries. The redox capability of the ROM was often proven to be effective in the solution-based redox mediation that facilitates both the charging and discharging reaction in metal-air batteries. Finally, we conclude this account by proposing the future research directions regarding the fundamental electrochemistry and the further practical development of ROMs for the sustainable rechargeable energy storage.

Efficacy and Safety of Rebamipide versus Its New Formulation, AD-203, in Patients with Erosive Gastritis: A Randomized, Double-Blind, Active Control, Noninferiority, Multicenter, Phase 3 Study.

Background/Aims: : The mucoprotective drug rebamipide is used to treat gastritis and peptic ulcers. We compared the efficacy of MucostaⓇ (rebamipide 100 mg) and its new formulation, AD-203 (rebamipide 150 mg), in treating erosive gastritis. Methods: This double-blind, active control, noninferiority, multicenter, phase 3 clinical trial randomly assigned 475 patients with endoscopically proven erosive gastritis to two groups: AD-203 twice daily or MucostaⓇ thrice daily for 2 weeks. The intention-to-treat (ITT) analysis included 454 patients (AD-203, n=229; MucostaⓇ, n=225), and the per-protocol (PP) analysis included 439 patients (AD-203, n=224; MucostaⓇ, n=215). The posttreatment assessments included the primary (erosion improvement rate) and secondary endpoints (erosion and edema cure rates; improvement rates of redness, hemorrhage, and gastrointestinal symptoms). Drug-related adverse events were evaluated. Results: According to the ITT analysis, the erosion improvement rates (posttreatment) in AD-203-treated and MucostaⓇ-treated patients were 39.7% and 43.8%, respectively. According to the PP analysis, the erosion improvement rates (posttreatment) in AD-203-treated and MucostaⓇ-treated patients were 39.3% and 43.7%, respectively. The one-sided 97.5% lower limit for the improvement rate difference between the study groups was -4.01% (95% confidence interval [CI], -13.09% to 5.06%) in the ITT analysis and -4.44% (95% CI, -13.65% to 4.78%) in the PP analysis. The groups did not significantly differ in the secondary endpoints in either analysis. Twenty-four AD-203-treated and 20 MucostaⓇ-treated patients reported adverse events but no serious adverse drug reactions; both groups presented similar adverse event rates. Conclusions: The new formulation of rebamipide 150 mg (AD-203) twice daily was not inferior to rebamipide 100 mg (MucostaⓇ) thrice daily. Both formulations showed a similar efficacy in treating erosive gastritis.

Tailoring the Self-Healing Properties of Conducting Polymer Films.

The conducting polymer polyethylenedioxythiophene doped with polystyrene sulfonate (PEDOT:PSS) has received great attention in the field of wearable bioelectronics due to its tunable high electrical conductivity, air stability, ease of processability, biocompatibility, and recently discovered self-healing ability. It has been observed that blending additives with PEDOT:PSS or post-treatment permits the tailoring of intrinsic polymer properties, though their effects on the water-enabled self-healing property have not previously been established. Here, it is demonstrated that the water-enabled healing behavior of conducting polymers is decreased by crosslinkers or by acid post-treatment. Organic dopants of PEDOT have high water swelling ratios and lead to water-enabled healing, while inorganic dopants fail in the healing of PEDOT. The water-enabled healing of two isolated PEDOT:PSS squares with a 5 µm width gap and a thickness less than 1 µm is shown. This work will help pave the way for the further development of conducting polymer-based self-healable bioelectronics and flexible and stretchable electronics.

Endoscopic Treatment of Subepithelial Tumors.

Gastrointestinal subepithelial tumors (SETs) are generally found during endoscopy and their incidence has gradually increased. Although the indications for the endoscopic treatment of patients with SETs remain to be established, the feasibility and safety of endoscopic dissection, including the advantages of this method compared with surgical treatment, have been validated in many studies. The development of endoscopic techniques, such as endoscopic submucosal dissection, endoscopic enucleation, endoscopic excavation, endoscopic submucosal tunnel dissection, submucosal tunnel endoscopic resection, and endoscopic full-thickness resection has enabled the removal of SETs while reducing the occurrence of complications. Here, we discuss the endoscopic treatment of patients with SETs, outcomes for endoscopic treatment, and procedure-related complications. We also consider the advantages and disadvantages of the various endoscopic techniques.

Endoscopic en bloc resection of an exophytic gastrointestinal stromal tumor with suction excavation technique.

Here, we report the first successful endoscopic resection of an exophytic gastrointestinal stromal tumor (GIST) using a novel perforation-free suction excavation technique. A 49-year-old woman presented for further management of a gastric subepithelial tumor on the lesser curvature of the lower body, originally detected via routine upper gastrointestinal endoscopy. Abdominal computed tomography and endoscopic ultrasound showed a 4-cm extraluminally protruding mass originating from the muscularis propria layer. The patient firmly refused surgical resection owing to potential cardiac problems, and informed consent was obtained for endoscopic removal. Careful dissection and suction of the tumor was repeated until successful extraction was achieved without serosal injury. We named this procedure the suction excavation technique. The tumor's dimensions were 3.5 cm × 2.8 cm × 2.5 cm. The tumor was positive for C-KIT and CD34 by immunohistochemical staining. The mitotic count was 6/50 high-power fields. The patient was followed for 5 years without tumor recurrence. This case demonstrated the use of endoscopic resection of an exophytic GIST using the suction excavation technique as a potential therapy without surgical resection.

The efficacy of transdermal fentanyl for pain relief after endoscopic submucosal dissection: a prospective, randomised controlled trial.

OBJECTIVE: Epigastric pain management following endoscopic submucosal dissection is an important consideration. This study aimed to investigate the utility and safety of fentanyl patches for pain relief after the procedure. METHODS: Patients who were scheduled to undergo endoscopic submucosal dissection were prospectively randomised to either a transdermal fentanyl patch group or a placebo control group. An additional pethidine was intravenously administered when pain developed and a numerical rating scale was used to evaluate both pre- and post-procedural pain. RESULTS: One hundred and ten patients were randomly assigned to receive either a 12 mcg/h fentanyl patch or a control patch on the night before the procedure. The fentanyl patch group had significantly lower pain scores immediately following the procedure (mean, 5.17 vs. 4.26, p=0.030). Maximal pain scores during the first 24 h (5.43 vs. 4.46, p=0.038) and pain scores on the day after the procedure (2.98 vs. 1.20, p<0.001) were also lower in the fentanyl patch group. In addition, the fentanyl patch group required a significantly lower dose of pethidine for pain management (24.54 vs. 11.25, p=0.004). CONCLUSIONS: The application of a transdermal fentanyl patch is an effective, convenient, and safe method to control epigastric pain after endoscopic submucosal dissection.

Do you have what it takes for challenging endoscopic submucosal dissection cases?

Endoscopic submucosal dissection (ESD) is a widely accepted treatment for early gastric cancer (EGC), especially in Korea and Japan. The criteria for the therapeutic use of ESD for EGC have been expanded recently. However, attention should be drawn to the technical feasibility of the ESD treatment which depends on a lesion's location, size or fibrosis level, or operator's experience. In the case of a lesion with a high level of difficulty, a more experienced operator is required. Thus, the treatment for a lesion with a high level of difficulty should be performed according to the degree of the operator's experience. In this paper, the authors describe the ESD procedure for lesions with a high level of difficulty.

[Gastritis cystica profunda accompanied by multiple early gastric cancers].

Gastritis cystica profunda (GCP) is a rare disease which shows multiple cystic gastric glands within the submucosa of the stomach. GCP lesions mainly develop at the site of gastroenterostomy and exhibit benign behavior. However, there have been a number of debates over its malignant potential. Several reports have documented GCP accompanied by gastric carcinomas, but the relationship between the two conditions remains uncertain. Here we report two cases of GCP with dysplasia accompanied by synchronous multiple early gastric cancers without previous gastric surgery.