Micro- and Nanometric Characterization of the Celestite Skeleton of Acantharian Species (Radiolaria, Rhizaria)

We studied the micrometric morphology and nanometric structure of the celestite (SrSO4) skeleton of acantharian family Acanthometridae. A body of the skeleton composed of 20 radial spines with four blades was characterized using microfocus X-ray computed tomography. The regular arrangement of three types of spines was clarified with the connection of the blades around the root of each spine. The surface of the spines was covered with a chitin-based organic membrane to prevent dissolution in sea water. On the nanometric scale, the mesocrystalline structure that consists of nanoscale grains having a distorted single-crystal nature was revealed using scanning and transmission electron microscopy, electron diffraction, and Raman spectroscopy. The acantharian skeletons have a crystallographically controlled architecture that is covered with a protective organic membrane.

Association between regular arrangement of collecting venules and Helicobacter pylori status in routine endoscopy

Background The sensitivity of regular arrangement of collecting venules (RAC)-positive pattern for predicting Helicobacter pylori (H. pylori)-negative status greatly altered from 93.8 to 48.0% in recent two decades of various studies, while the reason behind it remained obscure. The aim of this study was to investigate the value of RAC as an endoscopic feature for judging H. pylori status in routine endoscopy and reviewed the underlying mechanism. Methods A prospective study with high-definition non-magnifying endoscopy was performed. RAC-positive and RAC-negative patients were classified according to the collecting venules morphology of the lesser curvature in gastric corpus. Gastric biopsy specimens were obtained from the lesser and greater curvature of corpus with normal RAC-positive or abnormal RAC-negative mucosal patterns. Helicobacter pylori status was established by hematoxylin and eosin staining and immunohistochemistry. Results 41 RAC-positive and 124 RAC-negative patients were enrolled from June 2020 to September 2020. The prevalence of H. pylori infection in patients with RAC-positive pattern and RAC-negative pattern was 7.3% (3/41) and 71.0% (88/124), respectively. Among all 124 RAC-negative patients, 36 (29.0%) patients were H. pylori-negative status. Ten patients (32.3%) demonstrated RAC-positive pattern in 31 H. pylori-eradicated cases. The sensitivity, specificity, positive predictive value, and negative predictive value of RAC-positive pattern for predicting H. pylori-negative status were 51.4% (95% CI, 0.395–0.630), 96.7% (95% CI, 0.900–0.991), 92.7% (95% CI, 0.790–0.981), and 71.0% (95% CI, 0.620–0.786), respectively. Conclusions RAC presence can accurately rule out H. pylori infection of gastric corpus, and H. pylori-positive status cannot be predicted only by RAC absence in routine endoscopy. Trial registration The present study is a non-interventional trial.

Sulfone-functionalized poly(p-phenylene terephthalamide) copolymer fibers with improved interfacial adhesion to epoxy matrices

The poor interfacial adhesion of aramid fiber and matrix limits the application of the final composites. In this study, a series of the sulfone-functionalized poly( p-phenylene terephthalamide) (SPPTA) copolymers were satisfactorily synthesized and the effects of polymerization conditions (contents of the additional monomer and the cosolvent LiCl, molar concentration and ratio of the monomer, reaction temperature and time) on the molecular weight of the copolymer were discussed. The introduction of the sulfone group in aromatic polyamides not only increased the polarity of poly( p-phenylene terephthalamide) (PPTA) but destroyed the regular arrangement of the molecular chains, which greatly improved the surface free energy and the solubility of the polymers in organic solvents. The polymer maintained excellent thermal and interfacial properties. Compared with the PPTA fiber/epoxy composites, the interfacial shear strength (IFSS) of SPPTA fiber-reinforced epoxy composites reached 43.5 MPa, with a significantly enhancement of 20.8%, implying that the study provided an effective method to achieve highly interfacial adhesion of aramid fiber-reinforced composites.

Regular arrangement of collecting venules (RAC) as an endoscopic marker for exclusion of Helicobacter pylori (H. pylori) infection: A systematic review and meta-analysis

Background: Helicobacter pylori (H. pylori) is the most common cause of gastric cancer. Growing evidence suggests that the regular arrangement of collecting venules (RAC) can be used as an endoscopic marker to diagnose H. pylori infection. However, data on the diagnostic accuracy of RAC for H. pylori infection are conflicting. We performed a systematic review and meta-analysis of relevant studies to determine the diagnostic accuracy and clinical utility of RAC for the diagnosis of H. pylori infection. Methods: We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library between inception and Oct 29, 2020, for studies that assessed the diagnostic accuracy of RAC for H. pylori infection. Results: The literature search yielded 2921 nonduplicated screened titles, of which 58 underwent full-text review. Fifteen studies, representing a total of 6621 patients, met the inclusion criteria. The area under the summary receiver operating characteristic curve was 0.98 (95% CI 0.96 to 0.99). The pooled estimates for RAC were 0.98 (95% CI 0.95 to 0.99) for sensitivity and 0.75 (95% CI 0.54 to 0.88) for specificity. The pooled positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 3.8 (95% CI 1.9 to 7.7) and 0.03 (95% CI 0.02 to 0.07), respectively. Conclusions: RAC can be used as an endoscopic marker for exclusion of H. pylori infection. However, it cannot be recommended as a single indicator for the confirmation of H. pylori infection. The conclusion of this study should be treated with caution because significant heterogeneity exists between the evaluated studies.

Association Between Regular Arrangement of Collecting Venules and Helicobacter Pylori Status in Routine Endoscopy

Background: The sensitivity of regular arrangement of collecting venules (RAC)-positive pattern for predicting Helicobacter pylori (H. pylori)-negative status greatly altered from 93.8% to 48.0% in recent two decades of various studies, while the reason behind it remained obscure. The aim of this study was to investigate the value of RAC as an endoscopic feature for judging H. pylori status in routine endoscopy and reviewed the underlying mechanism.Methods: A prospective study with high-definition non-magnifying endoscopy was performed. RAC-positive and RAC-negative patients were classified according to the collecting venules morphology of the lesser curvature in gastric corpus. Gastric biopsy specimens were obtained from the lesser and greater curvature of corpus with normal RAC-positive or abnormal RAC-negative mucosal patterns. H. pylori status was established by hematoxylin and eosin staining and immunohistochemistry. Results: 41 RAC-positive and 124 RAC-negative patients were enrolled from June 2020 to September 2020. The prevalence of H. pylori infection in patients with RAC-positive pattern and RAC-negative pattern was 7.3% (3/41) and 71.0% (88/124), respectively. Among all 124 RAC-negative patients, 36 (29.0%) patients were H. pylori-negative status. Ten patients (32.3%) demonstrated RAC-positive pattern in 31 H. pylori-eradicated cases. The sensitivity, specificity, positive predictive value, and negative predictive value of RAC-positive pattern for predicting H. pylori negative status were 51.4% (95%CI, 0.395-0.630), 96.7% (95%CI, 0.900-0.991), 92.7% (95%CI, 0.790-0.981), and 71.0% (95%CI, 0.620-0.786), respectively.Conclusions: RAC presence can accurately rule out H. pylori infection of gastric corpus, and H. pylori-positive status cannot be predicted only by RAC absence in routine endoscopy.Trial registrationThe present study is a non-interventional trial.