The crystalline structure of anthracene (C14H10) under high pressure was studied performing angle dispersive x-ray diffraction experiments using synchrotron radiation in combination with Rietveld refinements and rigid body approximation. High hydrostatic pressure was applied up to 27.8 GPa using a diamond anvil cell. Full structural information (molecular orientations and lattice constants) is given up to a pressure of 20.3 GPa. At the highest pressure of 22.7 GPa the unit cell volume is decreased by 36.8%. Fourier transformation of the diffracted intensities reveals the electron density distribution within the unit cell. A pressure induced increase of the electron densities between adjacent molecules is observed. These findings are shown to be in agreement with theoretical calculations and hint towards the evolution of the anisotropic conductivity with pressure.

Superficial non-ampullary duodenal epithelial tumor (SNADET) is defined as a sporadic tumor that is confined to the mucosa or submucosa that does not arise from Vater's papilla, and it includes adenoma and adenocarcinoma. Recent developments in endoscopic technology, such as high-resolution endoscopy and image-enhanced endoscopy, may increase the chances of detecting SNADET lesions. However, because SNADET is rare, little is known about its preoperative endoscopic diagnosis. The use of endoscopic resection for SNADET, which has no risk of metastasis, is increasing, but the incidence of complications, such as perforation, is significantly higher than in any other part of the digestive tract. A preoperative diagnosis is required to distinguish between lesions that should be followed up and those that require treatment. Retrospective studies have revealed certain endoscopic findings that suggest malignancy. In recent years, several new imaging modalities have been developed and explored for real-time diagnosis of these lesion types. Establishing an endoscopic diagnostic tool to differentiate between adenoma and adenocarcinoma in SNADET lesions is required to select the most appropriate treatment. This review describes the current state of knowledge about preoperative endoscopic diagnosis of SNADETs, such as duodenal adenoma and duodenal adenocarcinoma. Newer endoscopic techniques, including magnifying endoscopy, may help to guide these diagnostics, but their additional advantages remain unclear, and further studies are required to clarify these issues.

Background and study aims: Although magnifying endoscopy with narrow-band imaging (M-NBI) is useful for the diagnosis of gastric mucosal lesions, differentiating between early cancer (EC) and low grade adenoma (LGA) remains a challenge. During M-NBI examination, we have noted the presence of a small, white lesion with a globular shape underneath cancerous gastric epithelium, and have termed this endoscopic finding the “white globe appearance” (WGA). The aim of this study was to determine whether or not the WGA could be an endoscopic marker for distinguishing EC from LGA. Methods: We retrospectively analyzed both the M-NBI scans and resected specimens of a total of 111 gastric lesions from 95 consecutive patients. Our main outcome was a difference in the prevalence of the WGA in EC and LGA. Results: The prevalence of the WGA in EC and LGA was 21.5 % (20 /93) and 0 % (0 /18), respectively (P = 0.039). The sensitivity, specificity, positive predictive value, and negative predictive value for differentiating between EC and LGA, according to the presence of the WGA, were 21.5, 100, 100, and 19.8 %, respectively. Conclusion: A positive WGA in a suspicious lesion on M-NBI would be an adjunct to the M-NBI diagnosis of possible EC because the specificity and positive predictive value of the WGA for differentiating between EC and LGA were extremely high. The WGA could be a novel endoscopic marker for differentiating between EC and LGA.

Background In biopsy specimens with low grade adenomas, it is often difficult to identify the presence of high grade adenomas or early carcinomas and low grade adenomas preoperatively, and clear guidelines have not yet been defined for the applicability of endoscopic treatment to low grade adenomas identified in biopsy specimens. Methods We aimed to clarify the usefulness of magnifying endoscopy with narrow band imaging (NBI) compared to conventional white light endoscopy for diagnosing actual high grade adenomas or early carcinomas with low grade adenomas, using the VS (microvascular pattern [V] and microsurface pattern [S]) classification for low grade adenomas in biopsy specimens. The study cohort consisted of 135 patients who were diagnosed with low grade adenomas in preoperative biopsy specimens and received endoscopic submucosal dissection. ResultsIn the elevated type of lesion, magnifying endoscopy with NBI diagnosed high grade adenomas or early carcinomas at a higher sensitivity and specificity than conventional white light endoscopy (82.4 vs. 70.6%, P = 0.391, 97.3 vs. 54.7%, P \ 0.0001). In the depressed macroscopic type of lesion, magnifying endoscopy with NBI also diagnosed high grade adenomas or early carcinomas at a higher sensitivity (95.5 vs. 68.2%, P = 0.0459) than conventional white light endoscopy. Although the specificity was high, at 100%, the difference when compared to conventional white light endoscopy was not significant (100 vs. 100%, P [ 0.99). Conclusions For low grade adenomas in biopsy specimens, it is vital to take sufficient consideration of endoscopic findings and not take action based only on the biopsy results. If a decision is made using the VS classification with magnifying endoscopy with NBI, actual high grade adenomas or early carcinomas can be differentiated from low grade adenomas so that endoscopic treatment can be performed more strictly.

The incidence of delayed perforation after endoscopic resection for superficial non-ampullary duodenal epithelial tumors is extremely high. Endoscopic tissue shielding with polyglycolic acid (PGA) sheets and fibrin glue is a promising method to prevent delayed perforation after endoscopic resection in the duodenum. However, we often encounter difficulty when covering an artificial ulcer with PGA sheets after endoscopic resection. We report three cases of postoperative ulcers covered by PGA sheets, fibrin glue, and clips.