115 research outputs found
(E)-N′-(2-Furylmethylene)benzohydrazide
In the title compound, C12H10N2O2, the dihedral angle between the benzene and furan rings is 52.54 (7)°. In the crystal, intermolecular N—H⋯O hydrogen bonds and C—H⋯π interactions link the molecules
(E)-N′-[1-(4-Bromophenyl)ethylidene]-2-hydroxybenzohydrazide
In the title compound, C15H13BrN2O2, the two aromatic rings form a dihedral angle of 7.9 (1)° and an intramolecular N—H⋯O hydrogen bond influences the molecular conformation. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules into chains propagated in [001]. The crystal packing exhibits also π–π interactions, which pair molecules into centrosymmetric dimers with short intermolecular distances of 3.671 (4) Å between the centroids of aromatic rings
N′-(2-Chlorobenzylidene)benzohydrazide
The asymmetric unit of the title compound, C14H11ClN2O, contains two independent molecules. In one molecule, the two aromatic rings form a dihedral angle of 45.94 (16)°, while in the second molecule this angle is 58.48 (16)°. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into two crystallographically independent sets of chains propagating along [001]
Poly[[bis(μ2-6-methylpyrazin-2-carboxylato-κ3 N 1,O:N 4)copper(II)] dihydrate]
In the title compound, {[Cu(C6H5N2O2)2]·2H2O}n, the CuII ion (site symmetry ) is coordinated by two N,O-bidentate ligands and two N-monodentate ligands in a distorted CuO2N4 octahedral geometry. Each anion acts as a bridge between two cations, thus forming a two-dimensional polymeric network parallel to the ab plane. The packing is consolidated by O—H⋯O hydrogen bonds. One of the O atoms of the ligand and both water molecules are disordered
(E)-N′-(4-Methoxybenzylidene)benzohydrazide
In the title molecule, C15H14N2O2, the dihedral angle between the benzene rings is 5.93 (17)°. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains propagating in [010]
The theoretical direct-band-gap optical gain of Germanium nanowires
We calculate the electronic structures of Germanium nanowires by taking the
effective-mass theory. The electron and hole states at the G-valley are studied
via the eight-band k.p theory. For the [111] L-valley, we expand the envelope
wave function using Bessel functions to calculate the energies of the electron
states for the first time. The results show that the energy dispersion curves
of electron states at the L-valley are almost parabolic irrespective of the
radius of Germanium nanowires. Based on the electronic structures, the density
of states of Germanium nanowires are also obtained, and we find that the
conduction band density of states mostly come from the electron states at the
L-valley because of the eight equivalent degenerate L points in Germanium.
Furthermore, the optical gain spectra of Germanium nanowires are investigated.
The calculations show that there are no optical gain along z direction even
though the injected carrier density is 4x1019 cm-3 when the doping
concentration is zero, and a remarkable optical gain can be obtained when the
injected carrier density is close to 1x1020 cm-3, since a large amount of
electrons will prefer to occupy the low-energy L-valley. In this case, the
negative optical gain will be encountered considering free-carrier absorption
loss as the increase of the diameter. We also investigate the optical gain
along z direction as functions of the doping concentration and injected carrier
density for the doped Germanium nanowires. When taking into account
free-carrier absorption loss, the calculated results show that a positive net
peak gain is most likely to occur in the heavily doped nanowires with smaller
diameters. Our theoretical studies are valuable in providing a guidance for the
applications of Germanium nanowires in the field of microelectronics and
optoelectronics
(E)-N′-[1-(4-Bromophenyl)ethylidene]benzohydrazide
The asymmetric unit of the title compound, C15H13BrN2O, contains two independent molecules with different conformations; the two aromatic rings form dihedral angles of 32.4 (4) and 27.5 (4)° in the two molecules. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link molecules into chains propagating in [100]
Effects of vertical shaft geometry on natural ventilation in urban road tunnel fires
A set of burning experiments were conducted to investigate the effect of vertical shaft geometry on natural ventilation in urban road tunnel fires. Results show that using vertical shafts to discharge smoke leads to a boundary layer separation near the right-angle connection of the shaft and the tunnel ceiling. In a low shaft, the turbulent-boundary-layer separation phenomenon causes relatively large-scale vortexes and restricts smoke from being exhausted, resulting in a negative effect on natural ventilation. Replacing the right-angle connection with the bevel-angle connection was proposed to split one separation point into two separation points, to attenuate the negative effect. The detailed characteristics of the separation phenomenon were analysed and the proposition was verified by Large Eddy Simulation. Results show that there are no relatively large-scale vortexes in shafts with bevel-angle connections, resulting in improved natural ventilation effectiveness. For lower shafts, the advantage of using the bevel-angle connection is more significant, and for shafts of the same height, the mass flow rate of smoke discharged by shafts with the bevel-angle connection increases up to 1.5 times of that by shafts with the right-angle connection. For relatively high shafts, it is about 1.2 times
Imaging characterization of myocardial function, fibrosis, and perfusion in a nonhuman primate model with heart failure-like features
INTRODUCTION: The availability of a human-like chronic heart failure (HF) animal model was critical for affiliating development of novel therapeutic drug treatments. With the close physiology relatedness to humans, the non-human primate (NHP) HF model would be valuable to better understand the pathophysiology and pharmacology of HF. The purpose of this work was to present preliminary cardiac image findings using echocardiography and cardiovascular magnetic resonance (CMR) in a HF-like cynomolgus macaque model.
METHODS: The NHP diet-induced model developed cardiac phenotypes that exhibited diastolic dysfunction with reduced left ventricular ejection fraction (LVEF) or preserved LVEF. Twenty cynomolgus monkeys with cardiac dysfunction were selected by echocardiography and subsequently separated into two groups, LVEF \u3c 65% (termed as HFrEF,
RESULTS: No LGE was observed in any monkey. Monkeys with HF-like features were significantly older, compared to the healthy control group. There were significant differences among the three groups in ECV (20.79 ± 3.65% in healthy controls; 27.06 ± 3.37% in HFpEF group, and 31.11 ± 4.50% in HFrEFgroup,
CONCLUSION: Our preliminary imaging findings demonstrated cardiac dysfunction, elevated ECV, and/or reduced MPR in this HF-like NHP model. This pilot study laid the foundation for further mechanistic research and the development of a drug testing platform for distinct HF pathophysiology
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