Identification of geographical areas with high burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in schools using spatial analyses has become an important tool to guide targeted interventions in educational setting. In this study, we aimed to explore the spatial distribution and determinants of coronavirus disease 2019 (COVID-19) among students aged 3–18 years in South Korea. We analysed the nationwide epidemiological data on laboratory-confirmed COVID-19 cases in schools and in the communities between January 2020 and October 2021 in South Korea. To explore the spatial distribution, the global Moran's I and Getis-Ord's G using incidence rates among the districts of aged 3–18 years and 30–59 years. Spatial regression analysis was performed to find sociodemographic predictors of the COVID-19 attack rate in schools and in the communities. The global spatial correlation estimated by Moran's I was 0.647 for the community population and 0.350 for the student population, suggesting that the students were spatially less correlated than the community-level outbreak of SARS-CoV-2. In schools, attack rate of adults aged 30–59 years in the community was associated with increased risk of transmission (P < 0.0001). Number of students per class (in kindergartens, primary schools, middle schools and high schools) did not show significant association with the school transmission of SARS-CoV-2. In South Korea, COVID-19 in students had spatial variations across the country. Statistically significant high hotspots of SARS-CoV-2 transmission among students were found in the capital area, with dense population level and high COVID-19 burden among adults aged 30–59 years. Our finding suggests that controlling community-level burden of COVID-19 can help in preventing SARS-CoV-2 infection in school-aged children.

How does collective memory shape politics in the domestic and international spheres? I argue that collective memory—an intersubjective understanding of the past—has no inherent meaning and its salience is entirely contextual. What it means politically depends on the historical trajectory through which it came to form and the political exigency for which it is mobilized in the present. I propose three strategies by which social actors mobilize collective memory: framing—negotiating how the past can be interpreted; accrediting—redefining which narrators are authorized to speak; and binding—enforcing the narrative bounds to which narrators must conform. Using this framework, I reassess the failure of South Korea–Japan reconciliation and find that it has as much to do with the mobilization of collective colonial memory in South Korea over the course of its democratization as with Japanese impenitence. Anti-Japanese memory reflects continued domestic political contestation about how South Korea remembers and identifies itself.

To evaluate the appropriateness of the screening strategy for healthcare personnel (HCP) during a hospital-associated Middle East Respiratory Syndrome (MERS) outbreak, we performed a serologic investigation in 189 rRT-PCR–negative HCP exposed and assigned to MERS patients. Although 20%–25% of HCP experienced MERS-like symptoms, none of them showed seroconversion by plaque reduction neutralization test (PRNT).

Infect Control Hosp Epidemiol 2017;38:234–238

Several reports have indicated that dietary intake of DHA is associated with lower prevalence of periodontitis. In the present study, we investigated the effect of DHA on the production of proinflammatory mediators in murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) isolated from Prevotellaintermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action. LPS was isolated from lyophilised P. intermedia ATCC 25 611 cells using the standard hot-phenol–water protocol. Culture supernatants were collected and assayed for NO, IL-1β and IL-6. Real-time PCR analysis was carried out to detect the expression of inducible NO synthase (iNOS), IL-1β, IL-6 and haeme oxygenase-1 (HO-1) mRNA. Immunoblot analysis was carried out to quantify the expression of iNOS and HO-1 protein and concentrations of signalling proteins. DNA-binding activities of NF-κB subunits were determined using an ELISA-based assay kit. DHA significantly attenuated the production of NO, IL-1β and IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. DHA induced the expression of HO-1 in cells treated with P. intermedia LPS. Selective inhibition of HO-1 activity by tin protoporphyrin IX significantly mitigated the inhibitory effects of DHA on LPS-induced NO production. DHA significantly attenuated the phosphorylation of c-Jun N-terminal kinase induced by LPS. In addition, DHA suppressed the transcriptional activity of NF-κB by regulating the nuclear translocation and DNA-binding activity of NF-κB p50 subunit and inhibited the phosphorylation of signal transducer and activator of transcription 1. Further in vivo studies are needed to better evaluate the potential of DHA in humans as a therapeutic agent to treat periodontal disease.

A systematic study of photoluminescence (PL) and time-resolved PL spectra from In0.15Ga0.85N/In0.015Ga0.985N quantum wells (QWs) with different Si doping concentration in the barriers has been carried out. As the Si doping concentration increases, the PL emission intensity was increased and the PL peak energy was blueshifted. The energy separation between the spontaneous emission (SPE) and stimulated emission (SE) peaks decrease with increasing Si doping concentration. We also observed that the slow decay time τ2 in the QWs decreases with increasing Si doping concentration, from ∼ 130 ns for [Si] = 2 × 1018 cm−3 to ∼ 30 ns for [Si] = 1 × 1019 cm−3. The PL emission peak shifts to lower energies with delay time after a pulsed excitation and this shift decreases with increasing Si doping concentration. The increased recombination rate, the decrease of peak shift with delay time, and the reduced separation between the SPE and SE peaks with increasing Si doping concentration are attributed to the screening of piezoelectric field by carriers originated from Si doped barriers.