8,326 research outputs found
Methyl (E)-3-(2-bromo-4,5-dimethoxybenzylidene)dithiocarbazate
The title compound, C11H13BrN2O2S2, was obtained from the condensation reaction of methyl dithiocarbazate and 2-bromo-4,5-dimethoxybenzaldehyde. In the molecule, the benzene ring and dithiocarbazate fragment are located on opposite sides of the C=N bond, showing an E conformation. The dithiocarbazate fragment is approximately planar (r.m.s deviation = 0.0281 Å) and the mean plane is oriented at a dihedral angle of 11.38 (15)° with respect to the benzene ring. In the crystal, pairs of N—H⋯S hydrogen bonds link the molecules into centrosymmetric dimers
Benzyl (E)-3-(2-methylbenzylidene)dithiocarbazate
The title compound, C16H16N2S2, was obtained from the condensation reaction of benzyl dithiocarbazate and 2-methylbenzaldehyde. The asymmetric unit contains two independent molecules. In both molecules, the methylphenyl ring and the dithiocarbazate fragment are located on opposite sides of the C=N bond, showing an E conformation. In each molecule, the dithiocarbazate fragment is approximately planar, the r.m.s deviations being 0.018 and 0.025 Å. The mean plane of dithiocarbazate group is oriented at dihedral angles of 7.9 (3) and 68.24 (12)°, respectively, to the methylphenyl and phenyl rings in one molecule, while the corresponding angles in the other molecule are 10.9 (3) and 69.76 (16)°. Intermolecular N—H⋯S hydrogen bonding occurs in the crystal structure to generate inversion dimers for both molecules
Multi-Scale Expressions of One Optimal State Regulated by Dopamine in the Prefrontal Cortex
The prefrontal cortex (PFC), which plays key roles in many higher cognitive processes, is a hierarchical system consisting of multi-scale organizations. Optimizing the working state at each scale is essential for PFC's information processing. Typical optimal working states at different scales have been separately reported, including the dopamine-mediated inverted-U profile of the working memory (WM) at the system level, critical dynamics at the network level, and detailed balance of excitatory and inhibitory currents (E/I balance) at the cellular level. However, it remains unclear whether these states are scale-specific expressions of the same optimal state and, if so, what is the underlying mechanism for its regulation traversing across scales. Here, by studying a neural network model, we show that the optimal performance of WM co-occurs with the critical dynamics at the network level and the E/I balance at the level of individual neurons, suggesting the existence of a unified, multi-scale optimal state for the PFC. Importantly, such a state could be modulated by dopamine at the synaptic level through a series of U or inverted-U profiles. These results suggest that seemingly different optimal states for specific scales are multi-scale expressions of one condition regulated by dopamine. Our work suggests a cross-scale perspective to understand the PFC function and its modulation
3-Chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinic acid–triphenylphosphine oxide (1/1)
In the title 1:1 adduct, C11H10ClN3O2·C18H15OP, the dihedral angle between the pyridine and pyrazole rings is 10.3 (2)°. The two components of the adduct are linked by an O—H⋯O hydrogen bond
Benzyl (E)-3-(4-methoxybenzylidene)dithiocarbazate
The title compound, C16H16N2OS2, was obtained from a condensation reaction of benzyl dithiocarbazate and 4-methoxybenzaldehyde. In the molecule, the methoxyphenyl ring and dithiocarbazate fragment are located on opposite sides of the C=N double bond, showing an E configuration. The dithiocarbazate fragment is approximately planar (r.m.s. deviation = 0.0052 Å); its mean plane is oriented at dihedral angles of 8.19 (15) and 85.70 (13)°, respectively, to the methoxyphenyl and phenyl rings. Intermolecular N—H⋯S hydrogen bonds and weak C—H⋯π interactions are observed in the crystal structure
Entanglement and quantum phase transition in alternating XY spin chain with next-nearest neighbour interactions
By using the method of density-matrix renormalization-group to solve the
different spin-spin correlation functions, the nearest-neighbouring
entanglement(NNE) and next-nearest-neighbouring entanglement(NNNE) of
one-dimensional alternating Heisenberg XY spin chain is investigated in the
presence of alternating nearest neighbour interactions of exchange couplings,
external magnetic fields and next-nearest neighbouring interactions. For
dimerized ferromagnetic spin chain, NNNE appears only above the critical
dimerized interaction, meanwhile, the dimerized interaction effects quantum
phase transition point and improves NNNE to a large value. We also study the
effect of ferromagnetic or antiferromagnetic next-nearest neighboring (NNN)
interactions on the dynamics of NNE and NNNE. The ferromagnetic NNN interaction
increases and shrinks NNE below and above critical frustrated interaction
respectively, while the antiferromagnetic NNN interaction always decreases NNE.
The antiferromagnetic NNN interaction results to a larger value of NNNE in
comparison to the case when the NNN interaction is ferromagnetic.Comment: 13 pages, 4 figures,. accepted by Chinese Physics B 2008 11 (in
press
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