Abstract
Wavelength-scale lasers provide promising applications through low power consumption requiring for optical cavities with increased quality factors. Cavity radiative losses can be suppressed ...strongly in the regime of optical bound states in the continuum; however, a finite size of the resonator limits the performance of bound states in the continuum as cavity modes for active nanophotonic devices. Here, we employ the concept of a supercavity mode created by merging symmetry-protected and accidental bound states in the continuum in the momentum space, and realize an efficient laser based on a finite-size cavity with a small footprint. We trace the evolution of lasing properties before and after the merging point by varying the lattice spacing, and we reveal this laser demonstrates the significantly reduced threshold, substantially increased quality factor, and shrunken far-field images. Our results provide a route for nanolasers with reduced out-of-plane losses in finite-size active nanodevices and improved lasing characteristics.
Abstract
Background
Coronavirus disease 2019 (COVID-19) was introduced in Korea early with a large outbreak in mid-February. We reviewed the public health interventions used during the COVID-19 ...outbreak and describe the impact on seasonal influenza activity in Korea.
Methods
National response strategies, public health interventions and daily COVID-19–confirmed cases in Korea were reviewed during the pandemic. National influenza surveillance data were compared between 7 sequential seasons. Characteristics of each season, including rate of influenza-like illness (ILI), duration of epidemic, date of termination of epidemic, distribution of influenza virus strain, and hospitalization, were analyzed.
Results
After various public health interventions including enforced public education on hand hygiene, cough etiquette, staying at home with respiratory symptoms, universal mask use in public places, refrain from nonessential social activities, and school closures the duration of the influenza epidemic in 2019/2020 decreased by 6–12 weeks and the influenza activity peak rated 49.8 ILIs/1000 visits compared to 71.9–86.2 ILIs/1000 visits in previous seasons. During the period of enforced social distancing from weeks 9–17 of 2020, influenza hospitalization cases were 11.9–26.9-fold lower compared with previous seasons. During the 2019/2020 season, influenza B accounted for only 4%, in contrast to previous seasons in which influenza B accounted for 26.6–54.9% of all cases.
Conclusions
Efforts to activate a high-level national response not only led to a decrease in COVID-19 but also a substantial decrease in seasonal influenza activity. Interventions applied to control COVID-19 may serve as useful strategies for prevention and control of influenza in upcoming seasons.
Memory T cell responses have been demonstrated in COVID-19 convalescents, but ex vivo phenotypes of SARS-CoV-2-specific T cells have been unclear. We detected SARS-CoV-2-specific CD8+ T cells by MHC ...class I multimer staining and examined their phenotypes and functions in acute and convalescent COVID-19. Multimer+ cells exhibited early differentiated effector-memory phenotypes in the early convalescent phase. The frequency of stem-like memory cells was increased among multimer+ cells in the late convalescent phase. Cytokine secretion assays combined with MHC class I multimer staining revealed that the proportion of interferon-γ (IFN-γ)-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to influenza A virus. Importantly, the proportion of IFN-γ-producing cells was higher in PD-1+ cells than PD-1− cells among multimer+ cells, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our current findings provide information for understanding of SARS-CoV-2-specific CD8+ T cells elicited by infection or vaccination.
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•SARS-CoV-2-specific CD8+ T cells are effector memory cells in convalescents•CCR7+CD45RA+ cells are increased among SARS-CoV-2-specific cells in the late phase•SARS-CoV-2-specific CD8+ T cells have fewer IFN-γ+ cells than flu-specific cells•PD-1-expressing SARS-CoV-2-specific CD8+ T cells are not exhausted but functional
T cell responses have been demonstrated in COVID-19 patients, but ex vivo phenotypes and functions of SARS-CoV-2-specific T cells remain unclear. Rha et al. examined SARS-CoV-2-specific CD8+ T cells in acute and convalescent COVID-19 patients using MHC class I multimers, finding that PD-1-expressing SARS-CoV-2-specific CD8+ T cells are not exhausted but functional.
Background:
Costal chondrocyte–derived pellet-type autologous chondrocyte implantation (CCP-ACI) has been introduced as a new therapeutic option for the treatment of articular cartilage defects. We ...had previously conducted a randomized controlled trial comparing CCP-ACI versus microfracture at 1 year postoperatively.
Purpose:
To compare the efficacy and safety of CCP-ACI versus microfracture for the treatment of articular cartilage defects of the knee at 5 years postoperatively.
Study Design:
Randomized controlled trial; Level of evidence, 2.
Methods:
This study describes the mean 5-year follow-up of a previously published prospective clinical trial. The previous prospective trial compared the results of CCP-ACI versus microfracture until 1 year of follow-up. Of the 30 patients who were included in the previous study, 25 were followed up for 5 years. Patients were evaluated based on clinical outcome scores (Lysholm score, International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score KOOS, and visual analog scale for pain), magnetic resonance imaging findings, and rates of treatment failure at last follow-up.
Results:
The MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score in the CCP-ACI group was significantly higher than that in the microfracture group at 5 years (62.3 vs 26.7, respectively; P < .0001). The Lysholm score and KOOS score in the CCP-ACI group were significantly higher than those in the microfracture group at 5 years (84.5 vs 64.9, respectively, and 390.9 vs 303.0, respectively; P = .023 and P = .017, respectively). There was 1 case of treatment failure that occurred in the microfracture group.
Conclusion:
The present randomized controlled trial indicated that the results of both procedures clinically and statistically significantly improved at 1 and 5 years’ follow-up in treating cartilage defects, but the results of CCP-ACI were superior to those of microfracture. Magnetic resonance imaging conducted at 1 year and 5 years after CCP-ACI revealed statistically significant superior structural integration with native cartilage tissue compared with microfracture.
Registration:
NCT03545269 (ClinicalTrials.gov)
This study aimed to demonstrate that the Patient Health Questionnaire (PHQ)-8 is not less useful than the PHQ-9 as a screening test for major depressive disorder (MDD).
We performed a retrospective ...analysis of 567 patients in psychiatric outpatient units. The Mini International Neuropsychiatric Interview was used to diagnose MDD. We derived the validity and reliability of the PHQ-8 and PHQ-9. To evaluate the ability of the PHQ-8 and PHQ-9 to discriminate MDD, we drew receiver operating characteristic (ROC) curves and compared the areas under the curves (AUCs).
Of the 567 participants, 207 (36.5%) were diagnosed with MDD. Cronbach's αs for the PHQ-8 and PHQ-9 were 0.892 and 0.876, respectively. Similar to the PHQ-9, the PHQ-8 was also associated with scores on the Hamilton Depression Rating Scale in a correlation analysis. When we drew ROC curves for the PHQ-8 and PHQ-9, there was no statistically significant difference in the AUCs. With a cutoff score of 10, the PHQ-8 showed a sensitivity of 58.3%, specificity of 83.1%, positive predictive value of 53.4%, and negative predictive value of 85.7%.
In a psychiatric outpatient sample, the PHQ-8 was as useful as the PHQ-9 for MDD screening.
•Clustering of hydrochemical data of urban groundwater in Seoul was performed.•The combined use of SOM and FCM was useful to interpret urban groundwater quality.•Three hydrochemical groups and their ...distributions were identified.•Leakage of sewage wastewater is a major cause of groundwater contamination.•Local denitrification is observed around underground facilities with pumping.
To make an overall assessment of the groundwater quality in Seoul city, we used the self-organizing map (SOM) technique in combination with fuzzy c-means (FCM) clustering. SOM visualizes complicate and multidimensional data structures on a 2D surface while the FCM algorithm creates overlapping cluster boundaries among samples that are continuously distributed over a data space. The combination of SOM and FCM clustering was expected to help characterize highly complicated urban groundwater quality. As a result, the SOM characterized 343 groundwater samples using 91 neurons, which were further classified by FCM clustering into three water groups. Group 1 addressed the least polluted groundwater (17% of the samples (n = 58), average TDS = 194.5 mg/L and NO3 = 6.9 mg/L) and occurred in the peripheral areas whose land cover is mainly occupied by forests. Increasing pH with increasing sodium and bicarbonate concentrations indicated that the hydrogeochemistry of Group 1 was largely controlled by water-rock interactions. Group 2 included the highly polluted groundwater (24% of the samples (n = 82), average TDS = 326.2 mg/L and NO3 = 42.6 mg/L), and sporadically occurred in Seoul, with no distinct spatial control. This group seemed to be affected by sewage from broken sewer pipes, which are a primary pollution source of Seoul groundwater and are ubiquitously distributed beneath the city. Group 3 water also represented the highly contaminated groundwater (30% of the samples (n = 103), average TDS = 527.1 mg/L), but contained low nitrate concentrations (average NO3 = 13.1 mg/L). Based on their spatial locations, intensive groundwater pumping from subway tunnels and other underground spaces at the city center seemed to drive the induced flow of organic contaminants, resulting in local reducing conditions sufficient for denitrification. The remaining 100 samples (29% of the samples) shared the hydrogeochemical properties of two or three groups. This study successfully characterized the spatial pattern of urban groundwater quality that is complicated by various contamination sources and hydrogeochemical processes. The combined use of SOM and FCM clustering was proven as a powerful tool to interpret nonlinear and highly heterogeneous environmental data for which it is difficult to define cluster boundaries. Taken together, our results contribute to a better management of urban groundwater in metropolitan cities under high risks of anthropogenic contamination.
Atlantic‐origin cold saline water has previously not been considered an important contributor to the nutrient supply in the Pacific Arctic due to the effective insulation by the overlying ...Pacific‐origin waters that separate the surface mixed layer from the deeper Atlantic Water. Based on hydrographic observations in the northwestern Chukchi Sea from 2015 to 2017, we demonstrate that the intrusion of Atlantic‐origin cold saline water into the halocline boundary between Pacific and Atlantic‐origin waters in 2017 lifted Pacific‐origin nutrients up to the surface layer. We find that the cyclonic atmospheric circulation in 2017 was considerably strengthened, leading to lateral intrusions of two bodies of cold halocline water from the Eurasian marginal seas into the northwestern Chukchi Sea. Our results reveal that the intrusions of cold halocline waters caused unprecedented shoaling of the nutricline and anomalously high surface phytoplankton blooms in typically highly oligotrophic surface waters in the region during summer.
Plain Language Summary
Nutrient depletion, especially nitrogen, in Arctic surface waters during the summer is common due to biological uptake and intense stratification caused by sea ice melting and riverine water inputs, which restricts the upward mixing of nutrients into the euphotic zone. Although Atlantic‐origin cold saline water has previously not been considered an important contributor to the nutrient supply in the Pacific Arctic, the results presented here show that the intrusion of Atlantic‐origin cold saline water into the halocline boundary layer between Pacific and Atlantic‐origin waters in the summer of 2017 was an essential mechanism responsible for transporting Pacific‐origin nutrients to the surface layer, leading to anomalously high surface phytoplankton blooms in typically highly oligotrophic surface waters in the northwestern Chukchi Sea.
Key Points
The nutricline shoaling by an intrusion of Atlantic‐origin cold saline water was observed in the northwestern Chukchi Sea in 2017
Pacific‐origin nutrients were lifted up to the surface layer by the intrusion of Atlantic‐origin cold saline water
The enhanced cyclonic ocean circulation triggered a pronounced transport of Atlantic‐origin cold saline water to the western Arctic Ocean
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