There is a long standing debate about whether or not the annual modulation signal reported by the DAMA/LIBRA collaboration is induced by Weakly Interacting Massive Particles (WIMP) in the galaxy's ...dark matter halo scattering from nuclides in their NaI(Tl) crystal target/detector. This is because regions of WIMP-mass vs. WIMP-nucleon cross-section parameter space that can accommodate the DAMA/LIBRA-phase1 modulation signal in the context of the standard WIMP dark matter galactic halo and isospin-conserving (canonical), spin-independent (SI) WIMP-nucleon interactions have been excluded by many of other dark matter search experiments including COSINE-100, which uses the same NaI(Tl) target/detector material. Moreover, the recently released DAMA/LIBRA-phase2 results are inconsistent with an interpretation as WIMP-nuclide scattering via the canonical SI interaction and prefer, instead, isospin-violating or spin-dependent interactions. Dark matter interpretations of the DAMA/LIBRA signal are sensitive to the NaI(Tl) scintillation efficiency for nuclear recoils, which is characterized by so-called quenching factors (QF), and the QF values used in previous studies differ significantly from recently reported measurements, which may have led to incorrect interpretations of the DAMA/LIBRA signal. In this article, the compatibility of the DAMA/LIBRA and COSINE-100 results, in light of the new QF measurements is examined for different possible types of WIMP-nucleon interactions. The resulting allowed parameter space regions associated with the DAMA/LIBRA signal are explicitly compared with 90% confidence level upper limits from the initial 59.5 day COSINE-100 exposure. With the newly measured QF values, the allowed 3σ regions from the DAMA/LIBRA data are still generally excluded by the COSINE-100 data.
The COSINE-100 dark matter search experiment has started taking physics data with the goal of performing an independent measurement of the annual modulation signal observed by DAMA/LIBRA. A muon ...detector was constructed by using plastic scintillator panels in the outermost layer of the shield surrounding the COSINE-100 detector. It detects cosmic ray muons in order to understand the impact of the muon annual modulation on dark matter analysis. Assembly and initial performance tests of each module have been performed at a ground laboratory. The installation of the detector in the Yangyang Underground Laboratory (Y2L) was completed in the summer of 2016. Using three months of data, the muon underground flux was measured to be 328 ± 1(stat.)± 10(syst.) muons/m2/day. In this report, the assembly of the muon detector and the results from the analysis are presented.
Identifying the extent of environmental contamination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for infection control and prevention. The extent of environmental ...contamination has not been fully investigated in the context of severe coronavirus disease (COVID-19) patients.
To investigate environmental SARS-CoV-2 contamination in the isolation rooms of severe COVID-19 patients requiring mechanical ventilation or high-flow oxygen therapy.
Environmental swab samples and air samples were collected from the isolation rooms of three COVID-19 patients with severe pneumonia. Patients 1 and 2 received mechanical ventilation with a closed suction system, while patient 3 received high-flow oxygen therapy and non-invasive ventilation. Real-time reverse transcription–polymerase chain reaction (rRT–PCR) was used to detect SARS-CoV-2; viral cultures were performed for samples not negative on rRT–PCR.
Of the 48 swab samples collected in the rooms of patients 1 and 2, only samples from the outside surfaces of the endotracheal tubes tested positive for SARS-CoV-2 by rRT–PCR. However, in patient 3's room, 13 of the 28 environmental samples (fomites, fixed structures, and ventilation exit on the ceiling) showed positive results. Air samples were negative for SARS-CoV-2. Viable viruses were identified on the surface of the endotracheal tube of patient 1 and seven sites in patient 3's room.
Environmental contamination of SARS-CoV-2 may be a route of viral transmission. However, it might be minimized when patients receive mechanical ventilation with a closed suction system. These findings can provide evidence for guidelines for the safe use of personal protective equipment.
The Higgs mechanism, i.e., spontaneous symmetry breaking of the quantum vacuum, is a cross-disciplinary principle, universal for understanding dark energy, antimatter and quantum materials, from ...superconductivity to magnetism. Unlike one-band superconductors (SCs), a conceptually distinct Higgs amplitude mode can arise in multi-band, unconventional superconductors via strong interband Coulomb interaction, but is yet to be accessed. Here we discover such hybrid Higgs mode and demonstrate its quantum control by light in iron-based high-temperature SCs. Using terahertz (THz) two-pulse coherent spectroscopy, we observe a tunable amplitude mode coherent oscillation of the complex order parameter from coupled lower and upper bands. The nonlinear dependence of the hybrid Higgs mode on the THz driving fields is distinct from any known SC results: we observe a large reversible modulation of resonance strength, yet with a persisting mode frequency. Together with quantum kinetic modeling of a hybrid Higgs mechanism, distinct from charge-density fluctuations and without invoking phonons or disorder, our result provides compelling evidence for a light-controlled coupling between the electron and hole amplitude modes assisted by strong interband quantum entanglement. Such light-control of Higgs hybridization can be extended to probe many-body entanglement and hidden symmetries in other complex systems.
Peanut (PN) and tree nuts (TNs) are common causes of anaphylaxis in Western countries, but no information is available in Korea. To feature clinical characteristics of anaphylaxis caused by PN, TNs, ...and seeds, a retrospective medical record review was performed in 14 university hospitals in Korea (2009–2013). One hundred and twenty‐six cases were identified, with the mean age of 4.9 years. PN, walnut (WN), and pine nut accounted for 32.5%, 41.3%, and 7.1%, respectively. The median values of specific IgE (sIgE) to PN, WN, and pine nut were 10.50, 8.74, and 4.61 kUA/l, respectively. Among 50 cases managed in the emergency department, 52.0% were treated with epinephrine, 66.0% with steroid, 94.0% with antihistamines, 36.0% with oxygen, and 48.0% with bronchodilator. In conclusion, WN, PN, and pine nut were the three most common triggers of anaphylaxis in Korean children, and anaphylaxis could occur at remarkably low levels of sIgE.
Objective. To investigate the expression of interleukin (IL)-23p19 in human rheumatoid arthritis (RA) synovial fibroblasts and its up-regulation by IL-17 stimulation, and to define the signal ...pathways involved in the regulation of IL-23p19 expression in RA synovial fibroblasts.
Methods. Synovial fluid (SF) and serum levels of IL-23p19 in RA were determined by enzyme-linked immunosorbent assays. The levels of IL-23p19 mRNA and protein were measured after the RA synovial fibroblasts were treated with recombinant human IL-17 and various inhibitors of intracellular signal pathway molecules using reverse transcription (RT) polymerase chain reaction (PCR), real-time PCR and western blotting.
Results. Levels of IL-23p19 in the sera and SF were much higher in RA patients than in osteoarthritis patients or healthy controls. The expression of IL-23p19 mRNA and protein was enhanced in RA synovial fibroblasts by IL-17 stimulation. Such effects of IL-17 were completely blocked by inhibitors of phosphatidylinositol (PI)-kinase/Akt, nuclear factor (NF)-κB and p38 mitogen-activated protein kinase (MAPK). In accordance with the expression of IL-23p19, the phosphorylation of IκB, Akt and p38 MAPK in synovial fibroblasts also increased after IL-17 stimulation.
Conclusion. IL-23p19 is over-expressed in RA synovial fibroblasts and IL-17 appears to up-regulate the expression of IL-23p19 in RA synovial fibroblasts via PI3-kinase/Akt, NF-κB- and p38-MAPK-mediated pathways. These results suggest that a disruption of interaction between IL-17 and IL-23p19 may provide a new therapeutic approach in the treatment of RA.
The COSINE-100 data acquisition system Adhikari, G.; Adhikari, P.; de Souza, E. Barbosa ...
Journal of instrumentation,
09/2018, Letnik:
13, Številka:
9
Journal Article
Recenzirano
COSINE-100 is a dark matter direct detection experiment designed to test the annual modulation signal observed by the DAMA/LIBRA experiment. COSINE-100 consists of 8 NaI(Tl) crystals with a total ...mass of 106 kg, a 2200 L liquid scintillator veto, and 37 muon detector panels. We present details of the data acquisition system of COSINE-100, including waveform storage using flash analog-to-digital converters for crystal events and integrated charge storage using charge-sensitive analog-to-digital converters for liquid scintillator and plastic scintillator muon veto events. We also discuss several trigger conditions developed in order to distinguish signal events from photomultiplier noise events. The total trigger rate observed for the crystal/liquid scintillator (plastic scintillator) detector is 15 Hz (24 Hz).
Giant Piezoelectricity on Si for Hyperactive MEMS Baek, S. H.; Park, J.; Kim, D. M. ...
Science (American Association for the Advancement of Science),
11/2011, Letnik:
334, Številka:
6058
Journal Article
Recenzirano
Microelectromechanical systems (MEMS) incorporating active piezoelectric layers offer integrated actuation, sensing, and transduction. The broad implementation of such active MEMS has long been ...constrained by the inability to integrate materials with giant piezoelectric response, such as Pb(MG 1/3 Nb 2/3 )O₃-PbTiO₃ (PMN-PT). We synthesized high-quality PMN-PT epitaxial thin films on vicinal (001) Si wafers with the use of an epitaxial (001) SrTiO₃ template layer with superior piezoelectric coefficients (e 31,f = -27 ± 3 coulombs per square meter) and figures of merit for piezoelectric energy-harvesting systems. We have incorporated these heterostructures into microcantilevers that are actuated with extremely low drive voltage due to thin-film piezoelectric properties that rival bulk PMN-PT single crystals. These epitaxial heterostructures exhibit very large electromechanical coupling for ultrasound medical imaging, microfluidic control, mechanical sensing, and energy harvesting.
Transportation of actinides through the geosphere is facilitated by complexation with organic ligands dissolved in groundwater. Carboxylic groups can interact directly with actinide ions and are ...found among the most abundant organic ligands in alkaline aquatic systems like underground water. In this study, the complexation of organic carboxylic groups with Am(
iii
) was investigated by monitoring the interactions of Am(
iii
) with oxalate (Ox), the simplest dicarboxylate ligand, in solution. UV-Vis spectrophotometry coupled with a liquid waveguide capillary cell (100 cm optical path-length) and time-resolved laser fluorescence spectroscopy were employed for quantitative detection of the respective Am(
iii
)-Ox species. Increasing the Ox concentration caused significant spectral changes,
i.e.
, red-shifts in both the absorption and luminescence maxima with increased molar absorption coefficients, enhanced luminescence intensities, and prolonged luminescence lifetimes. Individual spectra of AmOx
+
(aq)
, Am(Ox)
2
−
(aq)
, and Am(Ox)
3
3−
(aq)
were resolved by deconvolution of the absorption spectra, with apparent formation constants of log
β
1,1
= 5.34 ± 0.05, log
β
1,2
= 9.14 ± 0.18, and log
β
1,3
= 11.49 ± 0.30, respectively, in
I
= 0.1 M NaClO
4
and 0-30 mM Na
2
Ox. The absorption and luminescence spectral changes suggest bidentate complexation of Ox with Am(
iii
)
via
inner-sphere interactions. The geometry of the Am(
iii
)-Ox complexes was optimized by density functional theory, where the bonding characteristics were in good agreement with the experimental results. Thorough spectroscopic characterization enabled speciation of the Am(
iii
)-Ox complexes and determination of their formation constants. This spectroscopic approach is generally applicable in the investigation of molecular interactions between Am(
iii
) and various ligands in aqueous solution.
Speciation, thermodynamic stability, and structural information of aqueous oxalato-Am(
iii
) complexes were resolved by combinatorial use of UV-Vis-LWCC, TRLFS, and DFT calculations.
Assuming a standard Maxwellian for the WIMP velocity distribution, we obtain the bounds from null WIMP search results of 59.5 days of COSINE-100 data on the DAMA/LIBRA-phase2 modulation effect within ...the context of the non-relativistic effective theory of WIMP-nucleus scattering. Here, we systematically assume that one of the effective operators allowed by Galilean invariance dominates in the effective Hamiltonian of a spin-1/2 dark matter (DM) particle. We find that, although DAMA/LIBRA and COSINE-100 use the same sodium-iodide target, the comparison of the two results still depends on the particle-physics model. This is mainly due to two reasons: i) the WIMP signal spectral shape; ii) the expected modulation fractions, when the upper bound on the time-averaged rate in COSINE-100 is converted into a constraint on the annual modulation component in DAMA/LIBRA . We find that the latter effect is the dominant one. For several effective operators the expected modulation fractions are larger than in the standard spin-independent or spin-dependent interaction cases. As a consequence, compatibility between the modulation effect observed in DAMA/LIBRA and the null result from COSINE-100 is still possible for several non-relativistic operators. At low WIMP masses such relatively high values of the modulation fractions arise because COSINE-100 is mainly sensitive to WIMP-sodium scattering events, due to the higher threshold compared to DAMA/LIBRA . A next COSINE analysis is expected to have a full sensitivity for the 5 σ region of DAMA/LIBRA.
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