Effect of thermal inhomogeneity for THz radiation from intrinsic Josephson junction stacks of Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}

Terahertz radiation from the mesa structures of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ is detected in samples with thin electrodes $< 100$ nm. In samples with thick electrodes $\simeq$ 400 nm, neither radiations nor voltage jumps in current-voltage characteristics are detected. This suggests that the thin electrode helps excite the Josephson plasma oscillation as a result of the poor heat flow through the electrode. The shielding effect by the electrode is not essential. We consider that the local temperature rise is the origin of the synchronization of the phase kink for terahertz radiation.Comment: 4 pages, 3 figure

Association between Dental Caries and Influenza Infection in Children: A Japanese Nationwide Population-Based Study

Dental caries is the most common chronic childhood disease. Recent studies have suggested that dental caries harbor respiratory infections in adults. We investigated the association between dental caries and influenza in children. In this study, 42,812 children aged 2.5 years, 38,540 children aged 5.5 years, and 34,124 children aged 10 years were included in the analysis from the Longitudinal Survey of Newborns in the 21st Century in Japan, which targeted all children born during a certain period in 2001. We used information on dental caries treated at hospitals and clinics in the past year as exposure and influenza as outcome during the observation periods (1.5-2.5, 4.5-5.5, and 9-10 years of age). We performed a log-binomial regression analysis, adjusting for potential confounders, and stratified analysis according to previous dental caries status. The presence of dental caries increased the incidence of influenza in all three target ages compared with the absence of dental caries. The incidence of influenza increased with the presence of current dental caries, regardless of the presence of past dental caries. These associations were observed irrespective of household income. Early detection and treatment of dental caries may reduce the risk of influenza in children

Local SiC photoluminescence evidence of non-mutualistic hot spot formation and sub-THz coherent emission from a rectangular Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} mesa

From the photoluminescence of SiC microcrystals uniformly covering a rectangular mesa of the high transition temperature $T_c$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, the local surface temperature $T({\bm r})$ was directly measured during simultaneous sub-THz emission from the $N\sim10^3$ intrinsic Josephson junctions (IJJs) in the mesa. At high bias currents $I$ and low bath temperatures $T_{\rm bath}\lesssim~35$ K, the center of a large elliptical hot spot with $T({\bm r})> T_c$ jumps dramatically with little current-voltage characteristic changes. The hot spot doesn't alter the ubiquitous primary and secondary emission conditions: the ac Josephson relation and the electromagnetic cavity resonance excitation, respectively. Since the intense sub-THz emission was observed for high $T_{\rm bath}\gtrsim~50$ K in the low $I$ bias regime where hot spots are absent, hot spots can not provide the primary mechanisms for increasing the output power, the tunability, or for promoting the synchronization of the $N$ IJJs for the sub-THz emission, but can at best coexist non-mutualistically with the emission. No $T({\bm r})$ standing waves were observed

Investigation of laparoscopic therapy in 56 cases of duodenal ulcer perforation

Background: Although conservative therapy has been acceptable as the first-line therapy for duodenal ulcer (DU) perforations, surgical therapies are known to have certain advantages. We investigated the indications for laparoscopic (LS) or open surgery (OS) or conservative therapy (CoT) among 56 DU perforation cases over 5 years. Methods: 31 LSs, 22 OSs and 5 CoTs were analyzed for patient's physical and surgical factors and clinical course. Results: Mean age was 51.6. Male/female ratio was 49/9. Survival ratio was 98%. Although the hospital stay (10.9 vs 19.5 days) and analgesic administrations (1.9 vs 4.6 days) were significantly shorter in LS than OS, almost all OS patients were in serious condition as evidenced by longer waiting time before treatment, stronger pain, bigger hole of perforation, more ascites accumulation and higher morbidity of complications. Two cases of multisurgery were experienced in both LS and OS groups due to leakage of seam, abscess formation, relapsed ulcer or idiopathic intestinal perforation. LS is a therapy more widely usable and more beneficial than the other two. Conclusion: LS, a minimally invasive surgery for DU perforation, should be considered as a first-line standard therapy because of significant advantages such as shorter hospital stay. OS or CoT may be selected when appropriate

Crossover from crossing to tilted vortex phase in Bi2Sr2CaCu2O8+δ single crystals near ab-plane

International audienceIn extremely anisotropic layered superconductors of Bi2Sr2CaCu2O8+δ the stacks of vortex pancakes (PV) and the Josephson vortex (JV) interpenetrate, and due to PV-JV mutual pinning energy, weakly interact and form various tilted and crossing lattice structures including vortex chains, stripes, mixed chain + lattice phases, etc. In order to study these phenomena, it is decisive to have excellent quality of samples and the ideal experimental techniques. The vortex phases in high-quality Bi2Sr2CaCu2O8+δ single crystals were studied by in-plane resistivity measurement and local ac magnetic permeability. The sharp crossover was shown by both techniques, deep in the vortex solid state separating the Abrikosov dominant 'strong pinning' phase from the Josephson dominant 'weak pinning' phase. Those two vortex states were recognized as the mixed chain + lattice vortex phase and chains (tilted) vortex phase, respectively

Longitudinal impact of the COVID-19 pandemic on the development of mental disorders in preadolescents and adolescents

Background　School closures and social distancing may have affected mental health among preadolescent and adolescent children, who are in a social developmental stage. Rates of anxiety, depression, and stress have been reported to have increased during the COVID-19 pandemic among teenagers worldwide. However, most studies have measured children's mental health in cross-sectional studies or short-term comparisons before and after lockdowns and school closures, and few studies have tracked the long-term effects on mental health among children and adolescents, despite the pandemic lasting more than 2 years. Methods　An interrupted time-series analysis was performed for longitudinal changes in the monthly number of new mental disorders (eating disorders, schizophrenia, mood disorders, and somatoform disorders). Using a nationwide multicenter electronic health records database in Japan, we analyzed data of patients aged 9 to 18 years from 45 facilities that provided complete data throughout the study period. The study period covered January 2017 to May 2021, defining a national school closure as an intervention event. We modeled the monthly new diagnoses of each mental disorder using a segmented Poisson regression model. Results　The number of new diagnoses throughout the study period was 362 for eating disorders, 1104 for schizophrenia, 926 for mood disorders, and 1836 for somatoform disorders. The slope of the regression line in monthly number of new diagnoses increased in the post-pandemic period for all targeted mental disorders (change in slope for eating disorders 1.05, 95% confidence interval [CI] 1.00-1.11; schizophrenia 1.04, 95% CI 1.01-1.07; mood disorders 1.04, 95% CI 1.01-1.07; and somatoform disorders 1.04 95% CI 1.02-1.07). The number of new diagnoses for schizophrenia and mood disorders increased early after school closure; while eating disorders showed an increasing trend several months later. Somatoform disorders showed a decreasing trend followed by an increasing trend. Time trends by sex and age also differed for each mental disorder. Conclusions　In the post-pandemic period, the number of new cases increased over time for eating disorders, schizophrenia, mood disorders, and somatoform disorders. The timing of increase and trends by sex and age differed for each mental disorder

Lap-Protector and Circular Stapler Are Useful in Cystogastrostomy for Large Pancreatic Pseudocyst with Severe Infection

Lap-Protector, which is an abdominal wall sealing device, is usually used for wound protection from implantation of malignant cells or pyogenic fluid. A circular stapler is a common easy-to-use device for anastomosis of the digestive tract. We report the case of an infected pancreatic pseudocyst which was treated by surgical procedure using these useful devices. A 69-year-old man was followed up in our hospital after severe acute pancreatitis. He had undergone drainage surgeries twice for intractable pancreatic abscess followed by severe acute pancreatitis. He was admitted to our hospital complaining of loss of appetite, hiccups, and high fever. Computed tomography of the abdomen revealed an infected pancreatic pseudocyst which compressed the gastric wall. Internal drainage into the stomach was performed using Lap-Protector and circular stapler. The patient recovered uneventfully. Recently many endoscopic or laparoscopic procedures in cystogastrostomy are reported; however, a conventional open surgical approach is also important. This easy method may be useful for operative cystogastrostomy