4,364 research outputs found
MICROEMULSIONS: PLATFORM FOR IMPROVEMENT OF SOLUBILITY AND DISSOLUTION OF POORLY SOLUBLE DRUGS
ABSTRACTThis study reviews that solubilization of lipophilic drugs with low aqueous solubility has been a major trust area in recent years. It can be seen thatthere is a real and continuing need for the development of effective drug delivery systems for poorly water-soluble drugs to enhance their absorptionand bioavailability. One such approach might be pharmaceutical microemulsions as they have emerged as potential solubility enhancing technologies.Microemulsion system has considerable potential to act as a drug delivery vehicle by incorporating a wide range of drug molecules. Microemulsionhas got advantage like excellent thermodynamic stability, high drug solubilization capacity, improved oral bioavailability and protection againstenzymatic hydrolysis. This review focuses on the basic concept, formulation, characterization, and recent advances in microemulsions as novel drugdelivery system.Keywords: Microemulsion, Lipophilicity, Solubilization, Bioavailability, Phase behavior
Chiral extrapolation beyond the power-counting regime
Chiral effective field theory can provide valuable insight into the chiral
physics of hadrons when used in conjunction with non-perturbative schemes such
as lattice QCD. In this discourse, the attention is focused on extrapolating
the mass of the rho meson to the physical pion mass in quenched QCD (QQCD).
With the absence of a known experimental value, this serves to demonstrate the
ability of the extrapolation scheme to make predictions without prior bias. By
using extended effective field theory developed previously, an extrapolation is
performed using quenched lattice QCD data that extends outside the chiral
power-counting regime (PCR). The method involves an analysis of the
renormalization flow curves of the low energy coefficients in a finite-range
regularized effective field theory. The analysis identifies an optimal
regulator, which is embedded in the lattice QCD data themselves. This optimal
regulator is the regulator value at which the renormalization of the low energy
coefficients is approximately independent of the range of quark masses
considered. By using recent precision, quenched lattice results, the
extrapolation is tested directly by truncating the analysis to a set of points
above 380 MeV, while being blinded of the results probing deeply into the
chiral regime. The result is a successful extrapolation to the chiral regime.Comment: 8 pages, 18 figure
Numerical Simulation of Magnetic Interactions in Polycrystalline YFeO3
The magnetic behavior of polycrystalline yttrium orthoferrite was studied
from the experimental and theoretical points of view. Magnetization
measurements up to 170 kOe were carried out on a single-phase YFeO3 sample
synthesized from heterobimetallic alkoxides. The complex interplay between
weak-ferromagnetic and antiferromagnetic interactions, observed in the
experimental M(H) curves, was successfully simulated by locally minimizing the
magnetic energy of two interacting Fe sublattices. The resulting values of
exchange field (H_E = 5590 kOe), anisotropy field (H_A = 0.5 kOe) and
Dzyaloshinsky-Moriya antisymmetric field (H_D = 149 kOe) are in good agreement
with previous reports on this system.Comment: 26 pages, 9 figure
Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding
In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs) carbon fiber (CF) fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz). The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE) from -29.4 dB for CF/epoxy-composite to -51.1 dB for CF-MWCNT/epoxy multiscale composites of 2 mm thickness. In addition to enhanced EMI-SE, interlaminar shear strength improved from 23 MPa for CF/epoxy-composites to 50 MPa for multiscale composites indicating their usefulness for making structurally strong microwave shields. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported Licens
Emergence of metronidazole-resistant Bacteroides fragilis, India.
This article does not have an abstract
Correlation between the Surface Energetics of Reinforcement and Mechanical Properties of Carbon/Carbon Composites
Surface energetics of reinforcement is one of the most important properties in case of adhesion of reinforcement in composites . For this study, PAN fibres were stabilized isothermally with three different timings (viz. 0, 1, 2 h) and eventually prepared fibres having different surface energetics were evaluated by DCA 322. Composites
were made by using these stabilized fibres (designated as OP, 1 P, and 2P) with coal tar pitch as matrix precursor using match mould die technique. Green composites
were carbonized upto 1000°C, then impregnated and heat treated to 1500, 2000 and 2600°C. Green composites as well as heat treated composites were studied for their
mechanical properties . Microstructure as well as interfacial studies were carried out using optical microscope.
Optical microscopic examination of composite samples show that Ill treated fibres offer much better adhesion with matrix precursor and the matrix also exhibits
an obvious increase in the anisotropic domain size in case of 2P composites . Density of stabilized fibres and also of green composites has been found to increase with
stabilization time. Flexural strength of green composites prepared with 0 and 2h treated fibres decreases ( 123 MPa to 60 MPa). However, as a result of better bonding between
fibre and matrix , in case of IP composites , strength is always high except in green stage . An attempt has been made to correlate the surface energetics of fibre with
mechanical properties as well as matrix microstructure of carbon /carbon composites
Fuselage shell and cavity response measurements on a DC-9 test section
A series of fuselage shell and cavity response measurements conducted on a DC-9 aircraft test section are described. The objectives of these measurements were to define the shell and cavity model characteristics of the fuselage, understand the structural-acoustic coupling characteristics of the fuselage, and measure the response of the fuselage to different types of acoustic and vibration excitation. The fuselage was excited with several combinations of acoustic and mechanical sources using interior and exterior loudspeakers and shakers, and the response to these inputs was measured with arrays of microphones and accelerometers. The data were analyzed to generate spatial plots of the shell acceleration and cabin acoustic pressure field, and corresponding acceleration and pressure wavenumber maps. Analysis and interpretation of the spatial plots and wavenumber maps provided the required information on modal characteristics, structural-acoustic coupling, and fuselage response
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