Search results for "ddc:54"
showing 10 items of 218 documents
When Does Gold Behave as a Halogen? Predicted Uranium Tetraauride and Other MAu4 Tetrahedral Species, (M = Ti, Zr, Hf, Th)
2003
Quantum chemical calculations suggest that a series of molecules with the general formula MAu4 are stable, where M = U, Th, and a group-4 atom. They correspond to Au in the formal valence state -1 and indicate that gold can act as a ligand similar to the halogen series. Of the MAu4 species studied, UAu4, the first predicted mixed gold uranium compound, has a short M-Au bond distance, 2.71 A, which would locate Au between Br and I from the bond length point of view in the U-tetrahalide series. Energetically, the U-Au bond is weaker than the corresponding U-Br and U-I bonds.
Nanodiamond Theranostic for Light-Controlled Intracellular Heating and Nanoscale Temperature Sensing
2021
Temperature is an essential parameter in all biological systems, but information about the actual temperature in living cells is limited. Especially, in photothermal therapy, local intracellular temperature changes induce cell death but the local temperature gradients are not known. Highly sensitive nanothermometers would be required to measure and report local temperature changes independent of the intracellular environment, including pH or ions. Fluorescent nanodiamonds (ND) enable temperature sensing at the nanoscale independent of external conditions. Herein, we prepare ND nanothermometers coated with a nanogel shell and the photothermal agent indocyanine green serves as a heat generato…
Monitoring a Mechanochemical Reaction Reveals the Formation of a New ACC Defect Variant Containing the HCO 3 – Anion Encapsulated by an Amorphous Mat…
2020
Crystal growth & design 20(10), 6831 - 6846 (2020). doi:10.1021/acs.cgd.0c00912
Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei
2008
Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the ighest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than ~6 x 1019 eV and AGN at a distance less than ~75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest-energies originate fro…
Zenith distribution and flux of atmospheric muons measured with the 5-line ANTARES detector
2010
The ANTARES high energy neutrino telescope is a three-dimensional array of about 900 photomultipliers distributed over 12 mooring lines installed in the Mediterranean Sea. Between February and November 2007 it acquired data in a 5-line configuration. The zenith angular distribution of the atmospheric muon flux and the associated depth-intensity relation are measured and compared with previous measurements and Monte Carlo expectations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is presented.
Light-Activated Sensitive Probes for Amine Detection
2017
Our new, simple, and accurate colorimetric method is based on diarylethenes (DAEs) for the rapid detection of a wide range of primary and secondary amines. The probes consist of aldehyde- or ketone-substituted diarylethenes, which undergo an amine-induced decoloration reaction, selectively to give the ring-closed isomer. Thus, these probes can be activated at the desired moment by light irradiation, with a sensitivity that allows the detection of amines at concentrations as low as 10exp−6 M in solution. In addition, the practical immobilization of DAEs on paper makes it possible to detect biogenic amines, such as cadaverine, in the gas phase above a threshold of 12 ppbv within 30 seconds. P…
Search for low-energy neutrinos from astrophysical sources with Borexino
2019
We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos ($\bar{\nu}_e$) are detected in an organic liquid scintillator through the inverse $\beta$-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8-16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova $\bar{\nu}_e$ fluxes in the previously unexplored region below 8 MeV. A search for $\bar{\nu}_e$ in the solar ne…
Borexino’s search for low-energy neutrino and antineutrino signals correlated with gamma-ray bursts
2017
International audience; A search for neutrino and antineutrino events correlated with 2350 gamma-ray bursts (GRBs) is performed with Borexino data collected between December 2007 and November 2015. No statistically significant excess over background is observed. We look for electron antineutrinos ( ν¯e ) that inverse beta decay on protons with energies from 1.8 MeV to 15 MeV and set the best limit on the neutrino fluence from GRBs below 8 MeV. The signals from neutrinos and antineutrinos from GRBs that scatter on electrons are also searched for, a detection channel made possible by the particularly radio-pure scintillator of Borexino. We obtain currently the best limits on the neutrino f…
Autophagy
2012
Klionsky, Daniel J. et al.
Proton‐Gated Ring‐Closure of a Negative Photochromic Azulene‐Based Diarylethene
2020
Abstract Proton‐responsive photochromic molecules are attractive for their ability to react on non‐invasive rapid optical stimuli and the importance of protonation/deprotonation processes in various fields. Conventionally, their acidic/basic sites are on hetero‐atoms, which are orthogonal to the photo‐active π‐center. Here, we incorporate azulene, an acid‐sensitive pure hydrocarbon, into the skeleton of a diarylethene‐type photoswitch. The latter exhibits a novel proton‐gated negative photochromic ring‐closure and its optical response upon protonation in both open and closed forms is much more pronounced than those of diarylethene photoswitches with hetero‐atom based acidic/basic moieties. …