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Excitons, quasiparticles of electrons and holes bound by Coulombic attraction, are created transiently by light and play an important role in optoelectronics, photovoltaics and photosynthesis. They are also predicted to form spontaneously in a small-gap semiconductor or a semimetal, leading to a Bose–Einstein condensate at low temperature, but there has not been any direct evidence of this effect so far. Here we detect the photoemission signal from spontaneously formed excitons in a debated excitonic insulator candidate, Ta2NiSe5. Our symmetry-selective angle-resolved photoemission spectroscopy reveals a characteristic excitonic feature above the transition temperature, which provides detailed properties of excitons, such as the anisotropic Bohr radius. The present result provides evidence for so-called preformed excitons and guarantees the excitonic insulator nature of Ta2NiSe5 at low temperature.Excitons have been predicted to form spontaneously—without external excitation—in some materials. Low-temperature ARPES measurements on Ta2NiSe5 now provide evidence for such an excitonic insulator and for so-called preformed excitons.

Although functional dyspepsia (FD) is a common functional gastroduodenal disorder with a high socioeconomic burden, little is known about its global prevalence. Thus, we performed a comprehensive study to estimate long-term trends in the prevalence of FD. We searched PubMed/MEDLINE, Embase, and Google Scholar from 1990 to 2022 for population-based studies that reported the prevalence of FD in adults (≥ 18 years old) according to Rome I, II, III, or IV criteria. The prevalence of FD was extracted from included studies to obtain pooled prevalence with 95% confidence intervals (CI) and 95% prediction intervals. Subgroup analysis was performed according to certain characteristics, including geographic region. A total of 44 studies met the eligibility criteria, including 256,915 participants from 40 countries across six continents. The overall global pooled prevalence of FD was 8.4% (95% CI 7.4–.9.5). The prevalence was the highest in Rome I (11.9%; 95% CI 5.1–25.4) and lowest in Rome IV (6.8%; 95% CI 5.8–7.9). Developing countries showed a higher prevalence than developed countries (9.1% versus 8.0%), and prevalence was higher in women, irrespective of the definition used (9.0% versus 7.0%). The pooled prevalence gradually decreased from 1990 to 2020 (12.4% [8.2–18.3] in 1990–2002 versus 7.3% [6.1–8.7] in 2013–2020). The prevalence of FD differs by country, economic status, geographical region, and sex, and the global prevalence has been gradually declining. Despite the heterogeneity of sample population, our study estimates the current global burden of FD and provides information to heath care policy decisions.

Successful biliary cannulation is a prerequisite and important component of endoscopic retrograde cholangiopancreatography, but conventional cannulation methods (CCMs) have a postendoscopic retrograde cholangiopancreatography pancreatitis (PEP) rate of 14.1% in patients at high risk for PEP. The aim of this study was to evaluate the effectiveness and safety of needle-knife fistulotomy (NKF), compared with a CCM, when used for primary biliary access in patients at high risk for developing PEP. A total of 207 patients with one or more risk factors for PEP were prospectively enrolled. The patients were randomly allocated to one of 2 groups according to the primary biliary cannulation technique (NKF or CCM). We compared biliary cannulation success rates, cannulation and procedure times, and the incidence of adverse events, including PEP, between the groups. The mean number of PEP risk factors was similar between the groups (NKF, 2.2 ± 1.0; CCM, 2.2 ± 0.9). PEP occurred in 8 patients in the CCM group and in no patients in the NKF group (9.2% vs 0%, P < 0.001). The rates of other adverse events did not differ between the groups. The biliary cannulation success rate was high in the NKF group, but relatively low in the CCM group, possibly because of the stringent failure criteria aimed at reducing PEP. However, the mean cannulation and total procedural times were longer in the NKF group than in the CCM group. NKF is an effective and safe procedure to gain primary biliary access in patients at high risk for developing PEP. ClinicalTrials.gov, NCT02916199.

Endoscopic retrograde cholangiopancreatography (ERCP) training remains challenging. This study used 3D printing techniques to develop and optimize a portable ERCP training simulator and to implement basic and advanced practical techniques. Subsequently, we aimed to determine whether endoscopy trainees acquired proficiency in ERCP techniques and assess any improvements in their skill levels from using this model. An ERCP training model was generated using 3D printing techniques, including five distinct interchangeable and transparent ampullar–common bile duct (CBD) modules. A prospective study using this model was conducted with ten trainees. The technical success rate and examination times for duodenoscope insertion and biliary cannulation were evaluated. In addition, the successful plastic-stent insertion rate and trainee satisfaction were measured. The success rates for duodenoscopy, cannulation, and plastic stent insertion were 94, 100, and 92%, respectively. The mean satisfaction scores for duodenoscope insertion, cannulation, and plastic stent insertion were 4.4, 4.7, and 4.6 on a 5-point scale, respectively. Five attempts decreased the insertion time ( R  = − 0.591, P  < 0.001) and cannulation time ( R  = − 0.424, P  = 0.002). This ERCP-training silicon model is durable, simulates ERCP techniques easily, and helps trainees improve their ERCP techniques.

The recent clinical outcomes of multi-regimen chemotherapy included prolonged survival and a high rate of conversion to surgery in Asian patients with advanced biliary tract cancer. The ability of single-operator cholangioscopy (SOC) to detect and stage extrahepatic cholangiocarcinoma (CCC) in intraductal lesions is becoming more important in determining the extent of surgery. The aim of this study was to evaluate the role of SOC in surgical planning for extrahepatic CCC. We reviewed the consecutive data of patients who received nab-paclitaxel plus gemcitabine-cisplatin for the management of extrahepatic CCC and underwent preoperative evaluations between June 2020 and August 2022. SOC was performed to determine the precise extent of the disease in patients with a good response to chemotherapy who were considering surgical treatment. Among the 38 patients included, 30 (79%) were diagnosed with perihilar CCC, six (16%) with distal CCC, and two (5%) with intraductal papillary neoplasm of the bile duct. Intraductal evaluation with SOC altered disease extent defined by previous imaging findings in 14 (37%) patients. In those patients, five (36%) were changed to less extensive surgery, four (29%) to conversion surgery, four (29%) avoided surgery, and one (7%) was changed to more extensive surgery. Among the 38 included patients, 27 (71%) underwent surgery, and the accuracy of the visual impressions was 93%, as confirmed by the surgical pathology report. In conclusion, SOC examination of patients with potentially resectable extrahepatic CCC was more precise than conventional diagnostic evaluations and could help in planning surgical options.

BackgroundBalloon enteroscopy-assisted endoscopic retrograde cholangiopancreatography (BE-ERCP) has been reported to be effective for patients with surgically altered gastrointestinal anatomy. However, selective biliary cannulation remains difficult in BE-ERCP. We examined the usefulness of a modified double-guidewire technique using an uneven double lumen cannula (the uneven method) for BE-ERCP in patients with surgically altered gastrointestinal anatomy.MethodsTo clarify the usefulness of the uneven method for selective biliary cannulation in BE-ERCP in comparison to the pancreatic guidewire (PGW) method, 40 patients with surgically altered gastrointestinal anatomy who underwent BE-ERCP with successful placement of a guidewire in the pancreatic duct were evaluated. The uneven method was used in 18 cases (uneven group) and the PGW method was used in the remaining 22 cases (PGW group).ResultsThe technical success rate of biliary cannulation was higher in the uneven group than in the PGW group (83.3 vs. 59.0%; P = 0.165). In addition, the time to biliary cannulation were significantly shorter in the uneven group than in the PGW group (6 vs. 18 min; P = 0.004; respectively). In the PGW group, post-ERCP pancreatitis (PEP) occurred in 3 of 22 cases (13.6%). No adverse events, including PEP, occurred in the uneven group.ConclusionsThe uneven method may be a useful option of selective biliary cannulation in BE-ERCP for the patients with surgically altered gastrointestinal anatomy.

The use of endobiliary radiofrequency ablation (RFA) to generate a benign biliary stricture (BBS) model has a significant reproducibility problem. The aims of this animal study were to create an optimal BBS model using endobiliary RFA and determine the best way to develop it. The first step was performed on the common bile duct (CBD) of 10 miniature pigs using endoscopic RFA with a target temperature-controlled mode (80 ℃, 7 W for 90 s). The second step was performed on the CBD of five miniature pigs to understand more about the time-dependent changes in BBS development and the causes of adverse events. Using the conditions and techniques identified in the previous steps, the third step was conducted to create an optimal BBS model in 12 miniature pigs. In the first trial, four out of 10 animals died (40%) after the procedure due to cholangitis-induced sepsis. Based on this, biliary obstruction was prevented in further steps by placing a biliary plastic stent after RFA application. Histologic examinations over time showed that a severe abscess developed at the RFA application site on the fifth day, followed by fibrosis on the tenth day, and completion on the twentieth day. In the third trial, 11 animals survived (91.7%), the average BBS fibrotic wall thickness was 1107.9 µm (763.1–1864.6 µm), and the degree of upstream biliary dilation was 14.4 mm (11.05–20.7 mm). In conclusion, endobiliary RFA combined with a biliary plastic stent resulted in a safe and reproducible BBS animal model.

Background: While the side-by-side stenting technique-characterized by the parallel placement of stents offers procedural simplicity, the augmented radial force exerted by the initial stent may complicate subsequent deployment. This multicenter study evaluated the practicality and safety of bilateral side-by-side stenting using novel braided self-expandable metal stents (BenefitTM; M.I.Tech Co., Ltd., Pyeongtaek, Republic of Korea). Statistical analysis included survival analysis (Kaplan–Meier) and Cox proportional hazards regression to identify predictive factors. Patients and Methods: In this multicenter study, patients with inoperable malignant hilar biliary obstruction (Bismuth type II–IV) underwent simultaneous side-by-side endoscopic placement of two braided self-expandable metal stents. The primary outcome was stent patency. The secondary outcomes included technical and clinical success, and adverse events monitored for up to one year. Results: A total of 27 patients were included in the final analysis. The technical success rate was 92.6% (25/27), and the clinical success rate was 88.0% (22/25). The median stent patency was 93 days, with cumulative patency rates of 87.4% at 3 months and 49.7% at 12 months. Tumor ingrowth was the most common cause of stent occlusion (66.7%). Early adverse events occurred in 2 patients (one cholangitis and one stent migration), supporting the favorable safety profile of this approach. Conclusions: The simultaneous side-by-side placement of novel braided self-expandable metal stents yielded high technical success and favorable clinical outcomes in patients with inoperable malignant hilar biliary obstruction. This approach provided substantial stent patency with a low complication rate, supporting its utility as a safe and effective palliative strategy for the management of malignant hilar biliary obstruction.

Background/Objectives: Endobiliary brushing is usually performed in the diagnosis of indeterminate biliary strictures; however, in this setting, brush cytology is limited by a low diagnostic yield and sensitivity. Here, we compared the catheter flushing method (CFM) with the conventional cytologic method (CCM) in terms of cellularity and diagnostic performance. Methods: Endobiliary brushings were obtained during endoscopic retrograde cholangiopancreatography (ERCP) from patients with biliary strictures enrolled at six tertiary hospitals. Additionally, the CFM was performed after brushing. Using liquid-based cytologic preparations of samples, we assessed the diagnostic performance of the CCM using Pap staining and the CFM using methionyl-transfer RNA synthetase 1 (MARS1) immunofluorescence staining. Results: From a total of 399 patients (malignant, 253; benign, 146), 374 CCM samples and 361 CFM samples contained adequate cells, with no significant difference in diagnostic yield (93.7% vs. 90.5%, respectively; p = 0.088). The sensitivity of the CFM (90.3%) was significantly higher than that of the CCM (75.1%; p < 0.001), with no significant difference in accuracy between methods (81.2% vs. 82.6%, respectively; p = 0.608). Conclusions: The diagnostic yield of the CFM was comparable to that of the CCM. Additionally, the diagnostic performance of the CFM was comparable to that of the CCM. These findings indicate that the CFM could be an additional brush cytology method for sample collection in patients with indeterminate biliary strictures. Incorporating both the CCM and CFM might be expected to improve the diagnostic yield of brush cytology in the biliary strictures. Further prospective comparative studies between the CCM and CFM using the same staining method are needed to validate these findings.