1,196 research outputs found
Temperature dependence of circular DNA topological states
Circular double stranded DNA has different topological states which are
defined by their linking numbers. Equilibrium distribution of linking numbers
can be obtained by closing a linear DNA into a circle by ligase. Using Monte
Carlo simulation, we predict the temperature dependence of the linking number
distribution of small circular DNAs. Our predictions are based on flexible
defect excitations resulted from local melting or unstacking of DNA base pairs.
We found that the reduced bending rigidity alone can lead to measurable changes
of the variance of linking number distribution of short circular DNAs. If the
defect is accompanied by local unwinding, the effect becomes much more
prominent. The predictions can be easily investigated in experiments, providing
a new method to study the micromechanics of sharply bent DNAs and the thermal
stability of specific DNA sequences. Furthermore, the predictions are directly
applicable to the studies of binding of DNA distorting proteins that can
locally reduce DNA rigidity, form DNA kinks, or introduce local unwinding.Comment: 15 pages in preprint format, 4 figure
N′-[(E)-2-Hydroxybenzylidene]-5-methylisoxazole-4-carbohydrazide monohydrate
In the structure of the title compound, C12H11N3O3·H2O, the dihedral angle formed by the benzene and isoxazole rings is 2.03 (8)°. The molecular conformation is stabilized by an intramolecular O—H⋯N hydrogen bond. In the crystal structure, molecules are linked into a three-dimesional network by intermolecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds, and by π–π stacking interactions involving adjacent benzene and isoxazole rings [centroid–centroid separation = 3.663 (2) Å]
Discontinuous Galerkin Immersed Finite Volume Element Method for Anisotropic Flow Models in Porous Medium
By choosing the trial function space to the immersed finite element space and the test function space to be piecewise constant function space, we develop a discontinuous Galerkin immersed finite volume element method to solve numerically a kind of anisotropic diffusion models governed by the elliptic interface problems with discontinuous tensor-conductivity. The existence and uniqueness of the discrete scheme are proved, and an optimal-order energy-norm estimate and L2-norm estimate for the numerical solution are derived
Dopamine D 4 Receptors Modulate GABAergic Signaling in Pyramidal Neurons of Prefrontal Cortex
The D 4 modulation of GABA A receptor currents was blocked by protein kinase A (PKA) activation and occluded by PKA inhibition. Inhibiting the catalytic activity of protein phosphatase 1 (PP1) also eliminated the effect of PD168077 on GABA A currents. Furthermore, disrupting the association of the PKA/PP1 complex with its scaffold protein Yotiao significantly attenuated the D 4 modulation of GABA A currents, suggesting that Yotiao-mediated targeting of PKA/PP1 to the vicinity of GABA A receptors is required for the dopaminergic signaling. Together, our results show that activation of D 4 receptors in PFC pyramidal neurons inhibits GABA A channel functions by regulating the PKA/PP1 signaling complex, which could underlie the D 4 modulation of PFC neuronal activity and the actions of antipsychotic drugs
Rotation and alignment of high- orbitals in transfermium nuclei
The structure of nuclei with is investigated systematically by the
Cranked Shell Model (CSM) with pairing correlations treated by a
Particle-Number Conserving (PNC) method. In the PNC method, the particle number
is conserved and the Pauli blocking effects are taken into account exactly. By
fitting the experimental single-particle spectra in these nuclei, a new set of
Nilsson parameters ( and ) is proposed. The experimental kinematic
moments of inertia and the band-head energies are reproduced quite well by the
PNC-CSM calculations. The band crossing, the effects of high- intruder
orbitals and deformation are discussed in detail.Comment: To appear in the Proceedings of the International Nuclear Physics
Conference (INPC2013), June 2-7, 2013, Florence, Ital
Probucol alleviates atherosclerosis and improves high density lipoprotein function
<p>Abstract</p> <p>Background</p> <p>Probucol is a unique hypolipidemic agent that decreases high density lipoprotein cholesterol (HDL-C). However, it is not definite that whether probucol hinders the progression of atherosclerosis by improving HDL function.</p> <p>Methods</p> <p>Eighteen New Zealand White rabbits were randomly divided into the control, atherosclerosis and probucol groups. Control group were fed a regular diet; the atherosclerosis group received a high fat diet, and the probucol group received the high fat diet plus probucol. Hepatocytes and peritoneal macrophages were isolated for [<sup>3</sup>H] labeled cholesterol efflux rates and expression of ABCA1 and SR-B1 at gene and protein levels; venous blood was collected for serum paraoxonase 1, myeloperoxidase activity and lipid analysis. Aorta were prepared for morphologic and immunohistochemical analysis after 12 weeks.</p> <p>Results</p> <p>Compared to the atherosclerosis group, the paraoxonase 1 activity, cholesterol efflux rates, expression of ABCA1 and SR-BI in hepatocytes and peritoneal macrophages, and the level of ABCA1 and SR-BI in aortic lesions were remarkably improved in the probucol group, But the serum HDL cholesterol concentration, myeloperoxidase activity, the IMT and the percentage plaque area of aorta were significantly decreased.</p> <p>Conclusion</p> <p>Probucol alleviated atherosclerosis by improving HDL function. The mechanisms include accelerating the process of reverse cholesterol transport, improving the anti-inflammatory and anti-oxidant functions.</p
1-(4-Methylphenyldiazoniumyl)-2-naphtholate
In the title compound, C17H14N2O, the dihedral angle between the benzene ring and naphthalene ring system is 11.0 (3)°. The azo group adopts an anti configuration and an intramolecular N—H⋯O hydrogen bond exists. Molecules are packed by π–π interactions between adjacent molecule (closest approach between centroids of benzene and naphthalene rings of 3.501 Å)
2-(1,3-Dibenzylimidazolidin-2-ylidene)malononitrile
In the title molecule, C20H18N4, the imidazolidine ring makes dihedral angles of 86.74 (2) and 81.18 (3)° with the two phenyl rings. In the absence of classical intermolecular interactions, the crystal packing is stabilized by van der Waals forces
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