23,824 research outputs found
Prevention and treatment of diabetic retinopathy by natural antioxidant containing in chitosan-based nanomedicines
Oxidative processes are critical factors in ocular conditions that may lead to pathologies such as Diabetic Retinopahty due to structural and functional modification of the tissues, apoptosis of capillary cells and retinal microvascular changes, making the loss of vision inevitable. Application of antioxidants may reduce apoptosis and restores partially functional tissues. Considering the multiple benefits of antioxidants in DR and that conjunctival drug permeability improvement is one of the major challenges in ocular drug delivery, the major topic of this work is to study the absorption capacity and consequent bioavailability of natural antioxidants incorporated in chitosan-based nanoparticles to prevent and treat DR. In this regards, it is proposed to characterize, quantify and compare the antioxidant potential of Salvia sp. and Satureja montana extracts and their main pure antioxidants: rutin, caffeic and clorogenic acid. Then, antioxidant compounds are encapsulated into different chitosan-based nanoparticles, nanoparticles and release profile characterized and ocular permeation evaluated using in vitro cell models. Finally, the effect of antioxidant nanomedicines across human ocular is evaluated in diabetic animal after topical administration in vivo.info:eu-repo/semantics/publishedVersio
Charge Oscillations in Debye-Hueckel Theory
The recent generalized Debye-Hueckel (GDH) theory is applied to the
calculation of the charge-charge correlation function G_{ZZ}(r). The resulting
expression satisfies both (i) the charge neutrality condition and (ii) the
Stillinger-Lovett second-moment condition for all T and rho_N, the overall ion
density, and (iii) exhibits charge oscillations for densities above a "Kirkwood
line" in the (rho_N,T) plane. This corrects the normally assumed DH
correlations, and, when combined with the GDH analysis of the density
correlations, leaves the GDH theory as the only complete description of ionic
correlation functions, as judged by (i)-(iii), (iv) exact low-density (rho_N,T)
variation, and (v) reasonable behavior near criticality.Comment: 6 pages, EuroPhys.sty (now available on archive), 1 eps figur
SU(3) Mixing for Excited Mesons
The SU(3)-flavor symmetry breaking and the quark-antiquark annihilation
mechanism are taken into account for describing the singlet-octet mixing for
several nonets assigned by Particle Data Group(PDG). This task is approached
with the mass matrix formalism
Spacetime Defects: von K\'arm\'an vortex street like configurations
A special arrangement of spinning strings with dislocations similar to a von
K\'arm\'an vortex street is studied. We numerically solve the geodesic
equations for the special case of a test particle moving along twoinfinite rows
of pure dislocations and also discuss the case of pure spinning defects.Comment: 9 pages, 2figures, CQG in pres
On the Logarithmic Triviality of Scalar Quantum Electrodynamics
Using finite size scaling and histogram methods we obtain numerical results
from lattice simulations indicating the logarithmic triviality of scalar
quantum electrodynamics, even when the bare gauge coupling is chosen large.
Simulations of the non-compact formulation of the lattice abelian Higgs model
with fixed length scalar fields on lattices with ranging from
through indicate a line of second order critical points.
Fluctuation-induced first order transitions are ruled out. Runs of over ten
million sweeps for each produce specific heat peaks which grow
logarithmically with and whose critical couplings shift with picking
out a correlation length exponent of consistent with mean field
theory. This behavior is qualitatively similar to that found in pure
.Comment: 9 page
Structural and dynamical properties of a quasi-one-dimensional classical binary system
The ground state configurations and the \lq{}\lq{}normal\rq{}\rq{} mode
spectra of a -one-dimensional (Q1D) binary system of charged particles
interacting through a screened Coulomb potential are presented. The minimum
energy configurations were obtained analytically and independently through
molecular dynamic simulations. A rich variety of ordered structures were found
as a function of the screening parameter, the particle density, and the ratio
between the charges of the distinct types of particles. Continuous and
discontinuous structural transitions, as well as an unexpected symmetry
breaking in the charge distribution are observed when the density of the system
is changed. For near equal charges we found a disordered phase where a mixing
of the two types of particles occurs. The phonon dispersion curves were
calculated within the harmonic approximation for the one- and two-chain
structures.Comment: 11 pages, 11 fig
Utilização do búfalo como animal de trabalho no cultivo de hortaliças.
bitstream/item/57616/1/CPATU-ComTec56.pd
Vacuum Polarization for a Massless Spin-1/2 Field in the Global Monopole Spacetime at Nonzero Temperature
In this paper we present the effects produced by the temperature in the
renormalized vacuum expectation value of the zero-zero component of the
energy-momentum tensor associated with massless left-handed spinor field in the
pointlike global monopole spacetime. In order to develop this calculation we
had to obtain the Euclidean thermal Green function in this background. Because
the expression obtained for the thermal energy density cannot be expressed in a
closed form, its explicit dependence on the temperature is not completely
evident. So, in order to obtain concrete information about its thermal
behavior, we develop a numerical analysis of our result in the high-temperature
limit for specific values of the parameter which codify the presence
of the monopole.Comment: 22 pages, LaTex format, 5 figure
Síntese de intermediários-clave para a obtenção da durina, taxifilina e P-glicosiloximandelontrila.
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