Diffuse Neutrino Flux Based on the Rates of Core-Collapse Supernovae and Black Hole Formation Deduced from a Novel Galactic Chemical Evolution Model

Fluxes of the diffuse supernova neutrino background (DSNB) are calculated based on a new modeling of galactic chemical evolution, where a variable stellar initial mass function (IMF) depending on the galaxy type is introduced and black hole (BH) formation from the failed supernova is considered for progenitors heavier than 18$M_{\odot}$. The flux calculations are performed for different combinations of the star formation rate, nuclear equation of state, and neutrino mass hierarchy to examine the systematic effects from these factors. In any case, our new model predicts the enhanced DSNB $\bar{\nu}_{e}$ flux at E_\nu \gtsim 30~MeV and E_\nu \ltsim 10~MeV due to more frequent BH formation and a larger core collapse rate at high redshifts in the early-type galaxies, respectively. Event rate spectra of the DSNB $\bar{\nu}_{e}$ at a detector from the new model are shown and detectability at water-based Cherenkov detectors, SK-Gd and Hyper-Kamiokande, is discussed. In order to investigate impacts of the assumptions in the new model, we prepare alternative models based on the different IMF form and treatment of BH formation, and estimate discrimination capabilities between the new and alternative models at these detectors.Comment: 11 pages, 10 figures, 1 tabl

PT-symmetric non-Hermitian quantum many-body system using ultracold atoms in an optical lattice with controlled dissipation

We report our realization of a parity-time (PT) symmetric non-Hermitian many-body system using cold atoms with dissipation. After developing a theoretical framework on PT-symmetric many-body systems using ultracold atoms in an optical lattice with controlled dissipation, we describe our experimental setup utilizing one-body atom loss as dissipation with special emphasis on calibration of important system parameters. We discuss loss dynamics observed experimentally.Comment: 13 pages, 8 figure

Differentiation between non-hypervascular pancreatic neuroendocrine tumour and pancreatic ductal adenocarcinoma on dynamic computed tomography and non-enhanced magnetic resonance imaging

Purpose: To determine the differentiating features between non-hypervascular pancreatic neuroendocrine tumour (PNET) and pancreatic ductal adenocarcinoma (PDAC) on dynamic computed tomography (CT) and non-enhanced magnetic resonance imaging (MRI). Material and methods: We enrolled 102 patients with non-hypervascular PNET (n = 15) or PDAC (n = 87), who had undergone dynamic CT and non-enhanced MRI. One radiologist evaluated all images, and the results were subjected to univariate and multivariate analyses. To investigate reproducibility, a second radiologist re-evaluated features that were significantly different between PNET and PDAC on multivariate analysis. Results: Tumour margin (well-defined or ill-defined) and enhancement ratio of tumour (ERT) showed significant differences in univariate and multivariate analyses. Multivariate analysis revealed a predominance of well-defined tumour margins in non-hypervascular PNET, with an odds ratio of 168.86 (95% confidence interval [CI]: 10.62-2685.29; p < 0.001). Furthermore, ERT was significantly lower in non-hypervascular PNET than in PDAC, with an odds ratio of 85.80 (95% CI: 2.57-2860.95; p = 0.01). Sensitivity, specificity, and accuracy were 86.7%, 96.6%, and 95.1%, respectively, when the tumour margin was used as the criteria. The values for ERT were 66.7%, 98.9%, and 94.1%, respectively. In reproducibility tests, both tumour margin and ERT showed substantial agreement (margin of tumour, κ = 0.6356; ERT, intraclass correlation coefficients (ICC) = 0.6155). Conclusions: Non-hypervascular PNET showed well-defined margins and lower ERT compared to PDAC, with significant differences. Our results showed that non-hypervascular PNET can be differentiated from PDAC via dynamic CT and non-enhanced MRI

Portal Vein Stenting for Portal Vein Stenosis After Pancreatoduodenectomy : A Case Report

Portal vein stenosis, which results in serious clinical conditions such as gastrointestinal variceal bleeding and liver failure, is caused by hepatobiliary pancreatic cancer or major postoperative complications after hepatobiliary pancreatic surgery. In recent years, portal vein stenting under interventional radiology has been applied as a more useful treatment method for portal vein stenosis than invasive surgery. We herein report the successful use of a vascular stent for portal vein stenosis after pancreatoduodenectomy. A 66-year-old man with distal cholangiocarcinoma underwent subtotal stomach-preserving pancreatoduodenectomy with resection of the portal vein because of direct invasion to the main portal vein at our hospital. The portal vein was reconstructed without a venous graft. He developed jejunal bleeding near the pancreatojejunostomy on postoperative day (POD) 2. Although embolization of the responsible vessel achieved hemostasis, an intraoperatively inserted drainage tube was needed for a long period of time postoperatively because the embolized afferent jejunum was perforated. He was discharged on POD 39 after removal of the drainage tube. On POD 282, he was readmitted with melena and severe fatigue. Computed tomography revealed an obstruction of the reconstructed portal vein and varices at the hepaticojejunostomy site. We diagnosed variceal bleeding and performed percutaneous transhepatic stenting in the obstructed portal vein. The patient was discharged in good clinical condition on day 15 after stenting. In conclusion, portal vein stenting is a useful and less invasive therapy for portal vein stenosis

Traumatic Gastric Perforation Associated with Cardiopulmonary Resuscitation: A Case Report

Sternal and rib fractures are well-known complications of cardiopulmonary resuscitation (CPR). We experienced a rare case of traumatic gastric perforation associated with CPR that required emergency laparotomy. In this case, we examined whether surgery is essential for gastric perforation associated with CPR. A 67-year-old man experienced cardiopulmonary arrest in the workplace, and bystander CPR was performed by his colleagues. He was then transported by ambulance to our hospital. A large amount of free air was found in the peritoneal cavity on computed tomography at presentation, and perforation of the gastrointestinal tract was suspected. During emergency laparotomy, a 2-cm serosal-muscular layer tear was found in the gastric lesser curvature. The damaged stomach wall was repaired, the abdominal cavity was lavaged, and surgery was completed by placing a drainage tube. The patient’s postoperative course was good and he was discharged on the 26th postoperative day. Emergency laparotomy has been performed frequently for traumatic gastric perforation associated with CPR. However, emergency laparotomy may be avoided by conservative treatment in some cases. Traumatic gastric perforation associated with CPR is a serious complication; however, the life prognosis of cardiopulmonary arrest patients depends on the original disease and the success of CPR. Traumatic gastric perforation associated with CPR is rarely fatal, and bystanders should not hesitate to initiate CPR