1,212 research outputs found
1-[2-(2,4-Dinitrobenzylideneamino)phenyl]-3-phenylthiourea
In the title compound, C20H15N5O4S, the central benzene ring makes dihedral angles of 59.5 (1) and 51.7 (1)°, respectively, with the terminal phenyl and benzene rings. The molecular structure exhibits weak intramolecular N—H⋯N and C—H⋯S interactions. In the crystal structure, molecules are linked by weak intermolecular N—H⋯S and C—H⋯O interactions, forming a chain along [11]
Lie Group Analysis of Natural Convection Heat and Mass Transfer in an Inclined Surface
Natural convection heat transfer fluid flow past an inclined semiinfinite surface in the presence of solute concentration is investigated by Lie group analysis. The governing partial differential equations are reduced to a system of ordinary differential equations by the translation and scaling symmetries. An exact solution is obtained for translation symmetry and numerical solutions for scaling symmetry. It is found that the velocity increases and temperature and concentration of the fluid decrease with an increase in the thermal and solutal Grashof numbers. The velocity and concentration of the fluid decrease and temperature increases with increase in the Schmidt number
Adaptive Edge-Oriented Shot Boundary Detection
We study the problem of video shot boundary detection using an adaptive edge-oriented framework. Our approach is distinct in its use of multiple multilevel features in the required processing. Adaptation is provided by a careful analysis of these multilevel features, based on shot variability. We consider three levels of adaptation: at the feature extraction stage using locally-adaptive edge maps, at the video sequence level, and at the individual shot level. We show how to provide adaptive parameters for the multilevel edge-based approach, and how to determine adaptive thresholds for the shot boundaries based on the characteristics of the particular shot being indexed. The result is a fast adaptive scheme that provides a slightly better performance in terms of robustness, and a five fold efficiency improvement in shot characterization and classification. The reported work has applications beyond direct video indexing, and could be used in real-time applications, such as in dynamic monitoring and modeling of video data traffic in multimedia communications, and in real-time video surveillance. Experimental results are included
Hypoglycemic Effect of Macrocyclic Binuclear Oxovanadium (IV) Complex on Streptozotocin-Induced Diabetic Rats
Though vanadium complexes mimic the action of insulin,
owing to their toxicity, research is still in progress for a new
vanadium complex with maximum efficacy at low concentration
and without any side effects. A novel macrocyclic
binuclear oxovanadium complex was synthesized, its composition
and structure were confirmed by spectral studies
and its efficacy was studied in streptozotocin-induced diabetic
rats over a period of 30 days. The oral administration
of the complex normalizes the blood glucose level in
the diabetic rats and also maintains normoglycemia after
a glucose load. The biochemical studies revealed that the
complex is not toxic to the system. The nontoxic nature of
this complex may be due to the presence of the vanadyl
ions in an intact form. The study highlights the nontoxic
and hypoglycemic effects of the new macrocyclic binuclear
oxovanadium complex
A Unified treatment of small and large- scale dynamos in helical turbulence
Helical turbulence is thought to provide the key to the generation of
large-scale magnetic fields. Turbulence also generically leads to rapidly
growing small-scale magnetic fields correlated on the turbulence scales. These
two processes are usually studied separately. We give here a unified treatment
of both processes, in the case of random fields, incorporating also a simple
model non-linear drift. In the process we uncover an interesting plausible
saturated state of the small-scale dynamo and a novel analogy between quantum
mechanical (QM) tunneling and the generation of large scale fields. The steady
state problem of the combined small/large scale dynamo, is mapped to a
zero-energy, QM potential problem; but a potential which, for non-zero mean
helicity, allows tunneling of bound states. A field generated by the
small-scale dynamo, can 'tunnel' to produce large-scale correlations, which in
steady state, correspond to a force-free 'mean' field.Comment: 4 pages, 1 figure, Physical Review Letters, in pres
Kinematic alpha effect in isotropic turbulence simulations
Using numerical simulations at moderate magnetic Reynolds numbers up to 220
it is shown that in the kinematic regime, isotropic helical turbulence leads to
an alpha effect and a turbulent diffusivity whose values are independent of the
magnetic Reynolds number, \Rm, provided \Rm exceeds unity. These turbulent
coefficients are also consistent with expectations from the first order
smoothing approximation. For small values of \Rm, alpha and turbulent
diffusivity are proportional to \Rm. Over finite time intervals meaningful
values of alpha and turbulent diffusivity can be obtained even when there is
small-scale dynamo action that produces strong magnetic fluctuations. This
suggests that small-scale dynamo-generated fields do not make a correlated
contribution to the mean electromotive force.Comment: Accepted for publication in MNRAS Letter
Magnetic helicity density and its flux in weakly inhomogeneous turbulence
A gauge invariant and hence physically meaningful definition of magnetic
helicity density for random fields is proposed, using the Gauss linking
formula, as the density of correlated field line linkages. This definition is
applied to the random small scale field in weakly inhomogeneous turbulence,
whose correlation length is small compared with the scale on which the
turbulence varies. For inhomogeneous systems, with or without boundaries, our
technique then allows one to study the local magnetic helicity density
evolution in a gauge independent fashion, which was not possible earlier. This
evolution equation is governed by local sources (owing to the mean field) and
by the divergence of a magnetic helicity flux density. The role of magnetic
helicity fluxes in alleviating catastrophic quenching of mean field dynamos is
discussed.Comment: 4 pages, accepted by Ap
Micelles of Different Morphologies - Advantages of Worm-like Filomicelles of PEO-PCL in Paclitaxel Delivery
Worm-like and spherical micelles are both prepared here from the same amphiphilic diblock copolymer, poly(ethylene oxide)-b-poly (ε-caprolactone) (PEO [5 kDa]-PCL [6.5 kDa]) in order to compare loading and delivery of hydrophobic drugs. Worm-like micelles of this degradable copolymer are nanometers in cross-section and spontaneously assemble to stable lengths of microns, resembling filoviruses in some respects and thus suggesting the moniker filomicelles . The highly flexible worm-like micelles can also be sonicated to generate kinetically stable spherical micelles composed of the same copolymer. The fission process exploits the finding that the PCL cores are fluid, rather than glassy or crystalline, and core-loading of the hydrophobic anticancer drug delivery, paclitaxel (TAX) shows that the worm-like micelles load and solubilize twice as much drug as spherical micelles. In cytotoxicity tests that compare to the clinically prevalent solubilizer, Cremophor® EL, both micellar carriers are far less toxic, and both types of TAX-loaded micelles also show 5-fold greater anticancer activity on A549 human lung cancer cells. PEO-PCL based worm-like filomicelles appear to be promising pharmaceutical nanocarriers with improved solubilization efficiency and comparable stability to spherical micelles, as well as better safety and efficacy in vitro compared to the prevalent Cremophor® EL TAX formulation
1-(2,4-Dinitrophenyl)-5-ferrocenyl-3-methyl-1H-pyrazole
In the title compound, [Fe(C5H5)(C15H11N4O4)], the dinitrophenyl and cyclopentadienyl rings make dihedral angles of 53.61 (6) and 23.11 (9)°, respectively, with the pyrazole unit. The two cyclopentadienyl rings are in an eclipsed conformation. The crystal structure is stabilized by intermolecular C—H⋯O interactions, which link molecules into chains parallel to the b axis
- …