138 research outputs found
Protective effect of ethanolic leaf extract of Alphonsea sclerocarpa against ethylene glycol induced urolithiasis in rats
252-258Alphonsea sclerocarpa Thwaites belonging to the family Annonaceae is a small tree, which grows up to 10-15 m tall the leaves are simple and alternate. Despite its medicinal properties the plant seems to be less explored and hence this research aims at exploring the antiurolithiatic activity of ethanolic leaf extract of A. sclerocarpa on ethylene glycol induced urolithiasis in rats. A. sclerocarpa leaf powder was extracted using ethanol. The effect of ethanolic leaf extract of A. sclerocarpa (250 and 500 mg/kg, p.o.) was studied in experimentally induced renal stone in rats by in vivo model. Ethylene glycol model (0.75% in drinking water, for 28 days) was used for renal stone induction. The blood, urine and kidney samples were used for various parameters. The concentration of calcium, oxalate, phosphorus, creatinine and blood urea nitrogen was observed in each group. The phytochemical analysis was carried out to detect the presence of secondary metabolites like saponins and flavonoids in the ethanolic extract of A. sclerocarpa leaf extract. In ethylene glycol (0.75% v/v) treated animal model ethanolic extract of A. sclerocarpa leaf extract showed significant results on stone promoters (calcium oxalate, inorganic phosphate and sodium), kidney function parameters (uric acid, blood urea nitrogen, creatinine). On the basis of biochemical parameters and histopathological study it was confirmed that A. sclerocarpa leaf extract protected the renal cells from oxidative stress and injury induce by calcium oxalate crystals. The investigation of ethanolic extract of A. sclerocarpa leaf has shown promising antiurolithiatic activity and support folklore claims of these plants as antiurolithiatic. The mechanism of action of these plants for antiurolithiatic is apparently related to increased diuresis and lowering of urinary concentrations of stone-forming constituents, though it should be confirmed by the extensive exploratory studies
Protective effect of ethanolic leaf extract of Alphonsea sclerocarpa against ethylene glycol induced urolithiasis in rats
Alphonsea sclerocarpa Thwaites belonging to the family Annonaceae is a small tree, which grows up to 10-15 m tall the leaves are simple and alternate. Despite its medicinal properties the plant seems to be less explored and hence this research aims at exploring the antiurolithiatic activity of ethanolic leaf extract of A. sclerocarpa on ethylene glycol induced urolithiasis in rats. A. sclerocarpa leaf powder was extracted using ethanol. The effect of ethanolic leaf extract of A. sclerocarpa (250 and 500 mg/kg, p.o.) was studied in experimentally induced renal stone in rats by in vivo model. Ethylene glycol model (0.75% in drinking water, for 28 days) was used for renal stone induction. The blood, urine and kidney samples were used for various parameters. The concentration of calcium, oxalate, phosphorus, creatinine and blood urea nitrogen was observed in each group. The phytochemical analysis was carried out to detect the presence of secondary metabolites like saponins and flavonoids in the ethanolic extract of A. sclerocarpa leaf extract. In ethylene glycol (0.75% v/v) treated animal model ethanolic extract of A. sclerocarpa leaf extract showed significant results on stone promoters (calcium oxalate, inorganic phosphate and sodium), kidney function parameters (uric acid, blood urea nitrogen, creatinine). On the basis of biochemical parameters and histopathological study it was confirmed that A. sclerocarpa leaf extract protected the renal cells from oxidative stress and injury induce by calcium oxalate crystals. The investigation of ethanolic extract of A. sclerocarpa leaf has shown promising antiurolithiatic activity and support folklore claims of these plants as antiurolithiatic. The mechanism of action of these plants for antiurolithiatic is apparently related to increased diuresis and lowering of urinary concentrations of stone-forming constituents, though it should be confirmed by the extensive exploratory studies
Nanoscale fluid flows in the vicinity of patterned surfaces
Molecular dynamics simulations of dense and rarefied fluids comprising small
chain molecules in chemically patterned nano-channels predict a novel switching
from Poiseuille to plug flow along the channel. We also demonstrate behavior
akin to the lotus effect for a nanodrop on a chemically patterned substrate.
Our results show that one can control and exploit the behavior of fluids at the
nanoscale using chemical patterning.Comment: Phys. Rev. Lett. in pres
Boundary conditions at a fluid - solid interface
We study the boundary conditions at a fluid-solid interface using molecular
dynamics simulations covering a broad range of fluid-solid interactions and
fluid densities, and both simple and chain-molecule fluids. The slip length is
shown to be independent of the type of flow, but rather is related to the fluid
organization near the solid, as governed by the fluid-solid molecular
interactions.Comment: REVtex, to appear in Physical Review Letter
Role of Secondary Motifs in Fast Folding Polymers: A Dynamical Variational Principle
A fascinating and open question challenging biochemistry, physics and even
geometry is the presence of highly regular motifs such as alpha-helices in the
folded state of biopolymers and proteins. Stimulating explanations ranging from
chemical propensity to simple geometrical reasoning have been invoked to
rationalize the existence of such secondary structures. We formulate a
dynamical variational principle for selection in conformation space based on
the requirement that the backbone of the native state of biologically viable
polymers be rapidly accessible from the denatured state. The variational
principle is shown to result in the emergence of helical order in compact
structures.Comment: 4 pages, RevTex, 4 eps figure
Real Space Renormalization Group for Langevin Dynamics in Absence of Translational Invariance
A novel exact dynamical real space renormalization group for a Langevin
equation derivable from a Euclidean Gaussian action is presented. It is
demonstrated rigorously that an algebraic temporal law holds for the Green
function on arbitrary structures of infinite extent. In the case of fractals it
is shown on specific examples that two different fixed points are found at
variance with periodic structures. Connection with growth dynamics of
interfaces is also discussed.Comment: 22 pages, RevTex 3.0, 5 figures available upon request from
[email protected], to be published in J.Stat.Phy
Conformations of Proteins in Equilibrium
We introduce a simple theoretical approach for an equilibrium study of
proteins with known native state structures. We test our approach with results
on well-studied globular proteins, Chymotrypsin Inhibitor (2ci2), Barnase and
the alpha spectrin SH3 domain and present evidence for a hierarchical onset of
order on lowering the temperature with significant organization at the local
level even at high temperatures. A further application to the folding process
of HIV-1 protease shows that the model can be reliably used to identify key
folding sites that are responsible for the development of drug resistance .Comment: 6 pages, 3 eps figure
Protein design in a lattice model of hydrophobic and polar amino acids
A general strategy is described for finding which amino acid sequences have
native states in a desired conformation (inverse design). The approach is used
to design sequences of 48 hydrophobic and polar aminoacids on three-dimensional
lattice structures. Previous studies employing a sequence-space Monte-Carlo
technique resulted in the successful design of one sequence in ten attempts.
The present work also entails the exploration of conformations that compete
significantly with the target structure for being its ground state. The design
procedure is successful in all the ten cases.Comment: RevTeX, 12 pages, 1 figur
Steric constraints in model proteins
A simple lattice model for proteins that allows for distinct sizes of the
amino acids is presented. The model is found to lead to a significant number of
conformations that are the unique ground state of one or more sequences or
encodable. Furthermore, several of the encodable structures are highly
designable and are the non-degenerate ground state of several sequences. Even
though the native state conformations are typically compact, not all compact
conformations are encodable. The incorporation of the hydrophobic and polar
nature of amino acids further enhances the attractive features of the model.Comment: RevTex, 5 pages, 3 postscript figure
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