Possible origin of β\beta-relaxation in amorphous metal alloys from atomic-mass differences of the constituents

We employ an atomic-scale theory within the framework of nonaffine lattice dynamics to uncover the origin of the Johari-Goldstein (JG) $\beta$-relaxation in metallic glasses (MGs). Combining simulation and experimental data with our theoretical approach, we reveal that the large mass asymmetry between the elements in a La$_{60}$Ni$_{15}$Al$_{25}$ MG leads to a clear separation in the respective relaxation time scales, giving strong evidence that JG relaxation is controlled by the lightest atomic species present. Moreover, we show that only qualitative features of the vibrational density of states determine the overall observed mechanical response of the glass, paving the way for a possible unified theory of secondary relaxations in glasses

Ethyl 7-amino-1-cyclo­propyl-6-fluoro-8-meth­oxy-4-oxo-1,4-dihydro­quinoline-3-carboxyl­ate monohydrate

In the title compound, C16H17FN2O4·H2O, the dihedral angle between the heterocyclic ring and the benzene ring is 5.77 (9)°, that between the heterocycle and the ethoxy­carbonyl plane is 15.5 (1)°, and that between the heterocyclic ring and the cyclopropane ring is 67.75 (13)°. In the crystal structure, mol­ecules are linked into a ribbon-like structure along the c axis by N—H⋯O and O—H⋯O hydrogen bonds

1-[Bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl]-3-[bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl­methyl]imidazolium hexa­fluoro­phos­phate

In the title compound, C20H19N2 +·PF6 −, the two benzocyclo­butene units are essentially planar and they form dihedral angles of 38.0 (2) and 72.7 (2)°, with the central imidazolium ring. In the crystal structure, weak C—H⋯π and π-–π stacking inter­actions [centroid–centroid distance = 3.742 (2) Å] contribute to the stability of the crystal structure. The PF6 − ion is disordered over two positions with site occupancies of 0.869 (9) and 0.131 (9)

Euphorbia factor L8: a diterpenoid from the seeds of Euphorbia lathyris

The title compound [systematic name: (2S*,3S*,4R*,5R*,9S*,11S*,15R*)-5,15-diacet­oxy-3-nicotino­yloxy-14-oxolathyra-6(17),12(E)-diene], C30H37NO7, was isolated from the seeds of Euphorbia lathyris. The tricyclic diterpenoid molecule contains an 11-membered ring, a five-membered ring exhibiting an envelope conformation and a three-membered ring. The 11-membered ring is cis-fused with the three-membered ring and trans-fused with the five-membered ring

cis-4-(Tosyl­oxymeth­yl)cyclo­hexa­ne­carboxylic acid

The title compound, C15H20O5S, is an inter­mediate in the synthesis of novel amino­carboxylic acid derivatives. The cyclo­hexane ring exhibits a chair conformation. In the crystal structure, adjacent mol­ecules form dimers via O—H⋯O hydrogen bonds

Protective Role of Hydrogen Sulfide against Noise-Induced Cochlear Damage: A Chronic Intracochlear Infusion Model

Background: A reduction in cochlear blood flow plays an essential role in noise-induced hearing loss (NIHL). The timely regulation of cochlear perfusion determines the progression and prognosis of NIHL. Hydrogen sulfide (H 2S) has attracted increasing interest as a vasodilator in cardiovascular systems. This study identified the role of H2S in cochlear blood flow regulation and noise protection. Methodology/Principal Findings: The gene and protein expression of the H2S synthetase cystathionine-c-lyase (CSE) in the rat cochlea was examined using immunofluorescence and real-time PCR. Cochlear CSE mRNA levels varied according to the duration of noise exposure. A chronic intracochlear infusion model was built and artificial perilymph (AP), NaHS or DLpropargylglycine (PPG) were locally administered. Local sodium hydrosulfide (NaHS) significantly increased cochlear perfusion post-noise exposure. Cochlear morphological damage and hearing loss were alleviated in the NaHS group as measured by conventional auditory brainstem response (ABR), cochlear scanning electron microscope (SEM) and outer hair cell (OHC) count. The highest percentage of OHC loss occurred in the PPG group. Conclusions/Significance: Our results suggest that H2S plays an important role in the regulation of cochlear blood flow and the protection against noise. Further studies may identify a new preventive and therapeutic perspective on NIHL and othe

3,3′-[(tert-Butoxy­carbon­yl)aza­nedi­yl]dipropanoic acid

The title compound, C11H19NO6, is an important inter­mediate for the synthesis of cephalosporin derivatives. The N atom is in a planar configuration. In the crystal, mol­ecules are linked into zigzag layers parallel to (100) by O—H⋯O hydrogen bonds