We report the measurement of the two-neutrino double-beta ($2\nu\beta\beta$) decay of $^{100}$Mo to the ground state of $^{100}$Ru using lithium molybdate (\crystal) scintillating bolometers. The ...detectors were developed for the CUPID-Mo program and operated at the EDELWEISS-III low background facility in the Modane underground laboratory. From a total exposure of $42.235$ kg$\times$d, the half-life of $^{100}$Mo is determined to be $T_{1/2}^{2\nu}=7.12^{+0.18}_{-0.14}\,\mathrm{(stat.)}\pm0.10\,\mathrm{(syst.)}\times10^{18}$ years. This is the most accurate determination of the $2\nu\beta\beta$ half-life of $^{100}$Mo to date. We also confirm, with the statistical significance of $>3\sigma$, that the single-state dominance model of the $2\nu\beta\beta$ decay of $^{100}$Mo is favored over the high-state dominance model.
Myeloperoxidase (MPO), an oxidant-producing enzyme of neutrophils, has been shown to prime platelet activity promoting immunothrombosis. Native MPO is a homodimer, consisting of two identical ...protomers (monomer) connected by a single disulfide bond. But in inflammatory foci, MPO can be found both in the form of a monomer and in the form of a dimer. Beside MPO can also be in complexes with other molecules and be modified by oxidants, which ultimately affect its physicochemical properties and functions. Here we compared the effects of various forms of MPO as well as MPO in complex with ceruloplasmin (CP), a physiological inhibitor of MPO, on the platelet activity. Monomeric MPO (hemi-MPO) was obtained by treating the dimeric MPO by reductive alkylation. MPO was modified with HOCl in a molar ratio of 1:100 (MPO-HOCl). Using surface-enhanced Raman scattering (SERS) spectroscopy we showed that peaks at about 510 and 526 cm−1 corresponded to disulfide bond was recognizable in the SERS-spectra of dimeric MPO, absent in the spectrum of hemi-MPO and less intense in the spectra of MPO-HOCl, which indicates the partial decomposition of dimeric MPO with a disulfide bond cleavage under the HOCl modification. It was shown hemi-MPO to a lesser extent than dimeric MPO bound to platelets and enhanced their agonist-induced aggregation and platelet-neutrophil aggregate formation. MPO modified by HOCl and MPO in complex with CP did not bind to platelets and have no effect on platelet activity. Thus, the modification of MPO by HOCl, its presence in monomeric form as well as in complex with CP reduces MPO effect on platelet function and consequently decreases the risk of thrombosis in inflammatory foci.
The study results of disodium dimolybdate single crystal are presented on the basis of experimentally obtained data on heat capacity. The heat capacity of Na2Mo2O7 was measured by the adiabatic ...method in the range of 5.7–310 K. No anomalies in the heat capacity associated with the phase transition were found. Extrapolation of the heat capacity to 0 K by a physically reasonable equation was performed. The Debye temperature at absolute zero was obtained. Based on the experimental heat capacity, the phonon density of states and isobaric thermodynamic functions (entropy, enthalpy increment, and Gibbs free energy) from 0 to 310 K were calculated. Using information on Na2Mo2O7 density of states, zero-point energy and isochoric thermodynamic functions (entropy, internal energy increment, and reduced Helmholtz energy) from 0 to 848 K were calculated. The approach used to obtain the characteristics of solids is general and can be used to study a wide range of objects.
•Low temperature heat capacity of Na2Mo2O7 single crystal was measured.•Isobaric entropy, enthalpy, and Gibbs free energy were calculated.•Debye characteristic temperature at absolute zero was calculated.•Phonon density of states and zero-point energy were obtained.•Isochoric entropy, internal energy, and reduced Helmholtz energy were calculated.
A single crystal of Formula omitted (NWO) was grown by a low-thermal-gradient Czochralski technique (LTG-CZ). The scintillation properties of the crystal were evaluated for the first time as a ...potential material for dark matter search experiments. The luminescence and scintillation characteristics of the crystal were studied at room temperature and low temperatures by using a light-emitting diode (LED) and a Formula omitted beta source. The luminescence and scintillation light yield at 10 K were significantly higher than those at room temperature. The crystal showed higher light yield at 10 K than a CaMoO Formula omitted (CMO) crystal. The decay time of the crystal was investigated at temperatures between 10 and 300 K. The sensitivity to spin-independent weakly interacting massive particle-nucleon interactions based on 10 kg (2 months) and 50 kg (12 months) data for the NWO crystal detectors was estimated by a simulated experiment using the standard halo model. The luminescence, scintillation, and sensitivity results revealed that the NWO crystal is a promising candidate for a dark matter search experiment in the near future.
CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay (
0
ν
β
β
) of
100
Mo
. In this article, we detail the CUPID-Mo detector concept, assembly and installation in the ...Modane underground laboratory, providing results from the first datasets. The CUPID-Mo detector consists of an array of 20
100
Mo
-enriched 0.2 kg
Li
2
MoO
4
crystals operated as scintillating bolometers at
∼
20
mK
. The
Li
2
MoO
4
crystals are complemented by 20 thin Ge optical bolometers to reject
α
events by the simultaneous detection of heat and scintillation light. We observe a good detector uniformity and an excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Light collection ensures the rejection of
α
particles at a level much higher than 99.9% – with equally high acceptance for
γ
/
β
events – in the region of interest for
100
Mo
0
ν
β
β
. We present limits on the crystals’ radiopurity:
≤
3
μ
Bq/kg
of
226
Ra
and
≤
2
μ
Bq/kg
of
232
Th
. We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the
100
Mo
0
ν
β
β
decay in half-a-year’s livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology developed by the LUMINEU project and subsequently selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale bolometric
0
ν
β
β
experiment.
The far-side solar eruptive event SOL2014-09-01 produced hard electromagnetic and radio emissions that were observed with detectors at near-Earth vantage points. Especially challenging was a ...long-duration > 100 MeV
γ
-ray burst that was probably produced by accelerated protons exceeding 300 MeV. This observation raised the question how high-energy protons could reach the Earth-facing solar surface. Some preceding studies discussed a scenario in which protons accelerated by a shock driven by a coronal mass ejection high in the corona return to the solar surface. We continue with the analysis of this challenging event, involving radio images from the
Nançay Radioheliograph
and hard X-ray data from the
High Energy Neutron Detector
(HEND) of the
Gamma-Ray Spectrometer
onboard the
Mars Odyssey
space observatory located near Mars. HEND recorded unocculted flare emission. The results indicate that the emissions observed from the Earth’s direction were generated by flare-accelerated electrons and protons trapped in static long coronal loops. They can be reaccelerated in these loops by a shock wave that was excited by the eruption, being initially not driven by a coronal mass ejection. The results highlight ways to address the remaining questions.
In connection with the development of hydrogen energy, special attention is currently being paid to the creation of highly efficient water electrolyzers, including electrolyzers with alkaline ...electrolyte. The main disadvantage of hydrogen production by water electrolysis is its high energy consumption. The present article shows that energy consumption can be reduced by changing of the electrodes and diaphragm layout. The phase inversion method used for the manufacture of polymer-based porous diaphragms for alkaline water electrolysers made it possible to create an electrode-diaphragm assembly, where elements of electrode-diaphragm assembly represent a single element. The comparative research of electrolysis cells with different electrode-diaphragm assemblies and cells of the traditional "zero gap" was carried out.
Joint analysis of wind wave characteristics derived from Voluntary Observing Ships data (VOS) and the third-generation spectral wave model WAVEWATCH III v.5.16 hindcast is presented. Global ...distributions of significant wave heights and mean periods in both datasets demonstrate good qualitative and quantitative agreement, especially in regions with a high spatiotemporal density of observations. Simulation results and visually observed wind sea and swell show perfectly consistent patterns of directional steadiness. However, wind sea heights in WW3 are overestimated predominantly in stormy regions, while swell heights are globally underestimated. The reasons for these discrepancies in assessment of wave system components are investigated in the framework of various wave regime analyses.
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