Clustering and multiple-spreading events of nosocomial severe acute respiratory syndrome coronavirus 2 infection

Background

There is growing evidence that super-spreading events (SSEs) and multiple-spreading events (MSEs) are a characteristic feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, data regarding the possibility of SSEs or MSEs in healthcare settings are limited.

Methods

This study was performed at a tertiary-care hospital in Korea. We analysed the nosocomial COVID-19 cases that occurred in healthcare workers and inpatients and their caregivers between January and 20^th December 2020. Cases with two to four secondary cases were defined as MSEs and those with five or more secondary cases as SSEs.

Findings

We identified 21 nosocomial events (single-case events, N = 12 (57%); MSE + SSE, N = 9 (43%)) involving 65 individuals with COVID-19. Of these 65 individuals, 21 (32%) were infectors. The infectors tended to have a longer duration between symptom onset and diagnostic confirmation than did the non-infectors (median two days vs zero days, P=0.08). Importantly, 12 (18%) individuals were responsible for MSEs and one (2%) for an SSE, which collectively generated 35 (54%) secondary cases.

Conclusion

In a hospital with thorough infection-control measures, approximately 70% of the nosocomial cases of COVID-19 did not generate secondary cases, and one-fifth of the infectors were responsible for SSEs and MSEs, which accounted for approximately half of the total cases. Early case identification, isolation, and extensive contact tracing are important for the prevention of transmission and SSEs.

Multiharmonic Correlations of Different Flow Amplitudes in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

The event-by-event correlations between three flow amplitudes are measured for the first time in Pb-Pb collisions, using higher-order symmetric cumulants. We find that different three-harmonic correlations develop during the collective evolution of the medium when compared to correlations that exist in the initial state. These new results cannot be interpreted in terms of previous lower-order flow measurements since contributions from two-harmonic correlations are explicitly removed in the new observables. A comparison to Monte Carlo simulations provides new and independent constraints for the initial conditions and system properties of nuclear matter created in heavy-ion collisions.

Soft-Dielectron Excess in Proton-Proton Collisions at sqrt[s]=13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13  TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m_{ee}, p_{T,ee}, and event multiplicity dN_{ch}/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π^{0} ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<m_{ee}<0.6  GeV/c^{2} and for p_{T,ee}<0.4  GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m_{ee} and p_{T,ee} are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.

Mesorhizobium microcysteis sp. nov., isolated from a culture of Microcystis aeruginosa

Strain MaA-C15^T, a Gram-stain-negative, non-spore-forming and strictly aerobic bacterium, was isolated from a xenic culture of Microcystis aeruginosa in the Republic of Korea. Cells were motile rods showing positive reactions in catalase and oxidase tests. Growth was observed between 15 and 37 °C (optimum, 30 °C), between pH 6.0 and pH 11.0 (optimum, pH 7.5) and in the presence of 0-2.0 % (w/v) NaCl (optimum, 0 %). Strain MaA-C15^T contained C_16 : 0, 11-methyl-C_18 : 1  ω7c, cyclo-C_19 : 0  ω8c and summed feature 8 (C_18 : 1  ω6c and/or C_18 : 1  ω7c) as the major cellular fatty acids and ubiquinone-10 as the sole respiratory quinone. Phosphatidylethanolamine, phosphatidylmonomethylethanolamine, an unidentified aminophospholipid, an unidentified glycolipid and three unidentified phospholipids were detected as the major polar lipids. The G+C content of the genomic DNA was 64.1 mol%. Phylogenetic and phylogenomic analyses based on 16S rRNA gene and genome sequences revealed that strain MaA-C15^T formed a phyletic lineage with Mesorhizobium sediminum YIM M12096^T within the family Phyllobacteriaceae. Strain MaA-C15^T was most closely related to Mesorhizobium albiziae DSM 21822^T with a 98.2 % 16S rRNA sequence similarity. Average nucleotide identity and in silico DNA-DNA hybridization values between strain MaA-C15^T and M. albiziae DSM 21822^T were 75.4 and 20.1 %, respectively. Based on the results of phenotypic, chemotaxonomic and molecular analyses, strain MaA-C15^T represents a novel species of the genus Mesorhizobium, for which the name Mesorhizobium microcysteis sp. nov. is proposed. The type strain is MaA-C15^T (=KACC 21226^T=JCM 33503^T).

Association of ovarian response with picoAMH in women undergoing controlled ovarian hyperstimulation

OBJECTIVE

Our study aims to evaluate the diagnostic performance of a high-sensitivity picoAnti-Müllerian Hormone (picoAMH) for predicting ovarian response in women undergoing controlled ovarian hyperstimulation and occurrence of ovarian hyperstimulation syndrome.

METHODS

Retrospective cohort study at a single academic fertility center including all patients with picoAMH ELISA who underwent controlled ovarian hyperstimulation. The primary outcome was the number of oocytes retrieved, and secondary outcomes included cycle cancellation and ovarian hyperstimulation syndrome. Patients were grouped into poor, normal, and hyper-responders based on number of oocytes retrieved.

RESULTS

The mean AMH and antral follicle count (AFC) were significantly different between normal response vs. hyper response group (p < 0.0001). Only serum AMH and not AFC was significantly increased in patients diagnosed with ovarian hyperstimulation syndrome (OHSS). For prediction of OHSS, receiver operating characteristic (ROC) analysis revealed that AMH (area under the ROC curve [AUC] = 0.85) was significantly better than the AFC (AUC = 0.64). The serum AMH cut-off at sensitivity of 80% for predicting OHSS among hyper responders from ROC curve was 3.67 ng/ml. Serum AMH measured by picoAMH ELISA showed superior correlation to number of oocytes retrieved when compared to AFC in the age group over 40 years old (r² = 0.74 and r² = 0.4, respectively) CONCLUSION: This study shows great utility of picoAMH ELISA for predicting ovarian response to controlled ovarian hyperstimulation (COH). Diagnostic performance of picoAMH for prediction of OHSS is superior to the AFC in our cohort.

Parity-preserving and magnetic field-resilient superconductivity in InSb nanowires with Sn shells

Improving materials used to make qubits is crucial to further progress in quantum information processing. Of particular interest are semiconductor-superconductor heterostructures that are expected to form the basis of topological quantum computing. We grew semiconductor indium antimonide nanowires that were coated with shells of tin of uniform thickness. No interdiffusion was observed at the interface between Sn and InSb. Tunnel junctions were prepared by in situ shadowing. Despite the lack of lattice matching between Sn and InSb, a 15-nanometer-thick shell of tin was found to induce a hard superconducting gap, with superconductivity persisting in magnetic field up to 4 teslas. A small island of Sn-InSb exhibits the two-electron charging effect. These findings suggest a less restrictive approach to fabricating superconducting and topological quantum circuits.

Masking of High-Translucency Zirconia for Various Cores

CLINICAL RELEVANCE

Various core materials with different shades affect the final color of high-translucency monolithic zirconia restorations. The blue core shows the greatest color difference in final zirconia restorations followed by metal, A3 dentin-shade resin core, and white core.

SUMMARY

The purpose of this study was to evaluate the masking ability of high-translucency monolithic zirconia for various core materials. A computer-aided design-computer-aided manufacturing system was used to design a zirconia disc with a diameter of 10 mm and a thickness of 1.0 mm. Four groups of cores (n=15 each) were fabricated with blue-colored dual-cure resin, white-colored dual-cure resin, A3 dentin-shade composite resin, and titanium block with 10-mm diameter and 5-mm thickness.Dual-cure, self-adhesive resin cement discs with a thickness of 25.0 ± 0.02 μm were fabricated. The color was measured using a handheld spectrophotometer. Color measurements of all specimens were performed on a white background. To assess the masking ability of zirconia, the difference between the values measured with zirconia on a white background and the values measured with zirconia on each of the four types of core material as a background with the cement specimens interposed (zirconia + cement + core) was determined. To enhance the optical connection between the specimens, distilled water was applied between each layer during each measurement.The results showed that the value of ΔE was highest for the blue core followed by metal, A3 dentin-shade resin core, and white-resin core. No significant differences were observed between the metal core and the A3 dentin-shade resin core or between the A3 dentin-shade resin core and the white core. The blue core had the significantly highest ΔE value based on Tukey's honest significant difference test.Different core materials affect the final color of high-translucency monolithic zirconia restorations. Thus, our study showed that the final color of high-translucency monolithic zirconia restorations could be affected by the type of core material used.

Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v_{2}. The v_{2} coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (p_{T}) range 1.3-6  GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500  μm compared to that of charm hadrons and most of the other background sources. The v_{2} of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75  σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high p_{T}, but is in agreement with the results at low p_{T}. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.

Soft X-ray and ENA Imaging of the Earth's Dayside Magnetosphere

The LEXI and SMILE missions will provide soft X-ray images of the Earth's magnetosheath and cusps after their anticipated launch in 2023 and 2024, respectively. The IBEX mission showed the potential of an Energetic Neutral Atom (ENA) instrument to image dayside magnetosheath and cusps, albeit over the long hours required to raster an image with a single pixel imager. Thus, it is timely to discuss the two imaging techniques and relevant science topics. We simulate soft X-ray and low-ENA images that might be observed by a virtual spacecraft during two interesting solar wind scenarios: a southward turning of the interplanetary magnetic field and a sudden enhancement of the solar wind dynamic pressure. We employ the OpenGGCM global magnetohydrodynamics model and a simple exospheric neutral density model for these calculations. Both the magnetosheath and the cusps generate strong soft X-rays and ENA signals that can be used to extract the locations and motions of the bow shock and magnetopause. Magnetopause erosion corresponds closely to the enhancement of dayside reconnection rate obtained from the OpenGGCM model, indicating that images can be used to understand global-scale magnetopause reconnection. When dayside imagers are installed with high-ENA inner-magnetosphere and FUV/UV aurora imagers, we can trace the solar wind energy flow from the bow shock to the magnetosphere and then to the ionosphere in a self-standing manner without relying upon other observatories. Soft X-ray and/or ENA imagers can also unveil the dayside exosphere density structure and its response to space weather.

Nonlabens ponticola sp. nov., isolated from seawater and reclassification of Nonlabens sediminis as a later heterotypic synonym of Nonlabens tegetincola

A Gram-stain-negative, orange-pigmented and strictly aerobic bacterium, designated strain MJ115^T, was isolated from seawater in Pohang, South Korea. Cells were non-motile rods and showed positive reactions for catalase and oxidase tests. Growth of strain MJ115^T was observed at 4-35 °C (optimum, 30 °C), pH 6.0-7.0 (optimum, pH 6.5) and in the presence of 0-8.0 % (w/v) NaCl (optimum, 2.0%). Strain MJ115^T contained iso-C_15 : 0, anteiso-C_15 : 0, anteiso-C_17 : 1  ω9c, C_17 : 0 2-OH, iso-C_16 : 0 3-OH, iso-C_17 : 0 3-OH and summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) as major cellular fatty acids and menaquinone-6 as the major respiratory quinone. Phosphatidylethanolamine, two unidentified aminolipids and four unidentified lipids were detected as major polar lipids. The G+C content of the genomic DNA was 40.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MJ115^T formed a phyletic lineage with Nonlabens marinus S1-08^T, Nonlabens agnitus JC2678^T and Nonlabens antarcticus AKS 622^T within the genus Nonlabens. Strain MJ115^T was also most closely related to N. marinus S1-08^T, N. agnitus JC2678^T and N. antarcticus AKS 622^T with 96.5, 96.4 and 96.0 % 16S rRNA sequence similarities, respectively. Here it is proposed that strain MJ115^T represents a new species of the genus Nonlabens, for which the name Nonlabens ponticola sp. nov. is proposed. The type strain is MJ115^T (=KCTC 72237^T=NBRC 113963^T). In addition, the comparison of the whole genome sequences and phenotypic features suggested that Nonlabens tegetincola and Nonlabens sediminis belong to the same species. Therefore, it is proposed that N. sediminis is reclassified as a later heterotypic synonym of N. tegetincola.

Measurement of the Low-Energy Antideuteron Inelastic Cross Section

In this Letter, we report the first measurement of the inelastic cross section for antideuteron-nucleus interactions at low particle momenta, covering a range of 0.3≤p<4  GeV/c. The measurement is carried out using p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sqrt[s_{NN}]=5.02  TeV, recorded with the ALICE detector at the CERN LHC and utilizing the detector material as an absorber for antideuterons and antiprotons. The extracted raw primary antiparticle-to-particle ratios are compared to the results from detailed ALICE simulations based on the geant4 toolkit for the propagation of (anti)particles through the detector material. The analysis of the raw primary (anti)proton spectra serves as a benchmark for this study, since their hadronic interaction cross sections are well constrained experimentally. The first measurement of the inelastic cross section for antideuteron-nucleus interactions averaged over the ALICE detector material with atomic mass numbers ⟨A⟩=17.4 and 31.8 is obtained. The measured inelastic cross section points to a possible excess with respect to the Glauber model parametrization used in geant4 in the lowest momentum interval of 0.3≤p<0.47  GeV/c up to a factor 2.1. This result is relevant for the understanding of antimatter propagation and the contributions to antinuclei production from cosmic ray interactions within the interstellar medium. In addition, the momentum range covered by this measurement is of particular importance to evaluate signal predictions for indirect dark-matter searches.