3,466 research outputs found
Recent strategies in resveratrol delivery systems
Resveratrol, a natural polyphenolic stilbenoid widely found in grapes and wines, displays beneficial properties such as cardio-protective, antioxidant and anti-inflammatory activities. Trans-resveratrol (RSV) is the most bioactive and more abundant stereoisomer found in nature. Despite the positive properties of RSV, there are various factors that limit its effectiveness, including low aqueous solubility, low oral bioavailability and chemical instability. During the last years, an increasing number of strategies such as nano and micro encapsulation have been developed in order to overcome these limitations and enhance the use of RSV in nutritional and pharmaceutical applications. This Review summarizes the advances and main properties of several RSV carriers and delivery systems reported during the last 5 years.Fil: Machado, Noelia Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Fernández, Mariana Adela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Díaz, David Díaz. Universitat Regensburg; Alemani
Diffraction-limited imaging with monolayer 2D material-based ultrathin flat lenses.
Ultrathin flat optics allow control of light at the subwavelength scale that is unmatched by traditional refractive optics. To approach the atomically thin limit, the use of 2D materials is an attractive possibility due to their high refractive indices. However, achievement of diffraction-limited focusing and imaging is challenged by their thickness-limited spatial resolution and focusing efficiency. Here we report a universal method to transform 2D monolayers into ultrathin flat lenses. Femtosecond laser direct writing was applied to generate local scattering media inside a monolayer, which overcomes the longstanding challenge of obtaining sufficient phase or amplitude modulation in atomically thin 2D materials. We achieved highly efficient 3D focusing with subwavelength resolution and diffraction-limited imaging. The high focusing performance even allows diffraction-limited imaging at different focal positions with varying magnifications. Our work paves the way for downscaling of optical devices using 2D materials and reports an unprecedented approach for fabricating ultrathin imaging devices
Measurement of a reaction-diffusion crossover in exciton-exciton recombination inside carbon nanotubes using femtosecond optical absorption
Exciton-exciton recombination in isolated semiconducting single-walled carbon
nanotubes was studied using femtosecond transient absorption. Under sufficient
excitation to saturate the optical absorption, we observed an abrupt transition
between reaction- and diffusion- limited kinetics, arising from reactions
between incoherent localized excitons with a finite probability of ~ 0.2 per
encounter. This represents the first experimental observation of a crossover
between classical and critical kinetics in a 1D coalescing random walk, which
is a paradigm for the study of non- equilibrium systems.Comment: Accepted for Physical Review Letters. Title changed, and "exciton
fusion" replaced by "exciton-exciton recombination". Present address of Prof
Tom Brown added. 12 pages plus 3 figure
Hall effect of charge carriers in a correlated system
The dynamical Hall response in a correlated electronic system is analysed
within the linear response theory for tight binding models. At the d.c.
Hall constant for a single quasiparticle is expressed explicitly via the charge
stiffness, and a semiclassical result is recovered. As expected a hole-like
response is found for the mobile hole introduced into a quantum
antiferromagnet, as represented by the model.Comment: 4 pages, RevTeX, no figure
Impact of Smoking Status on Mortality in STEMI Patients Undergoing Mechanical Reperfusion for STEMI: Insights from the ISACS-STEMI COVID-19 Registry
The so-called \"smoking paradox\", conditioning lower mortality in smokers among STEMI patients, has seldom been addressed in the settings of modern primary PCI protocols. The ISACS-STEMI COVID-19 is a large-scale retrospective multicenter registry addressing in-hospital mortality, reperfusion, and 30-day mortality among primary PCI patients in the era of the COVID-19 pandemic. Among the 16,083 STEMI patients, 6819 (42.3%) patients were active smokers, 2099 (13.1%) previous smokers, and 7165 (44.6%) non-smokers. Despite the impaired preprocedural recanalization (p < 0.001), active smokers had a significantly better postprocedural TIMI flow compared with non-smokers (p < 0.001); this was confirmed after adjustment for all baseline and procedural confounders, and the propensity score. Active smokers had a significantly lower in-hospital (p < 0.001) and 30-day (p < 0.001) mortality compared with non-smokers and previous smokers; this was confirmed after adjustment for all baseline and procedural confounders, and the propensity score. In conclusion, in our population, active smoking was significantly associated with improved epicardial recanalization and lower in-hospital and 30-day mortality compared with previous and non-smoking history
Two-dimensional Superfluidity and Localization in the Hard-Core Boson Model: a Quantum Monte Carlo Study
Quantum Monte Carlo simulations are used to investigate the two-dimensional
superfluid properties of the hard-core boson model, which show a strong
dependence on particle density and disorder. We obtain further evidence that a
half-filled clean system becomes superfluid via a finite temperature
Kosterlitz-Thouless transition. The relationship between low temperature
superfluid density and particle density is symmetric and appears parabolic
about the half filling point. Disorder appears to break the superfluid phase up
into two distinct localized states, depending on the particle density. We find
that these results strongly correlate with the results of several experiments
on high- superconductors.Comment: 10 pages, 3 figures upon request, RevTeX version 3, (accepted for
Phys. Rev. B
New measurement of via neutron capture on hydrogen at Daya Bay
This article reports an improved independent measurement of neutrino mixing
angle at the Daya Bay Reactor Neutrino Experiment. Electron
antineutrinos were identified by inverse -decays with the emitted
neutron captured by hydrogen, yielding a data-set with principally distinct
uncertainties from that with neutrons captured by gadolinium. With the final
two of eight antineutrino detectors installed, this study used 621 days of data
including the previously reported 217-day data set with six detectors. The
dominant statistical uncertainty was reduced by 49%. Intensive studies of the
cosmogenic muon-induced Li and fast neutron backgrounds and the
neutron-capture energy selection efficiency, resulted in a reduction of the
systematic uncertainty by 26%. The deficit in the detected number of
antineutrinos at the far detectors relative to the expected number based on the
near detectors yielded in the
three-neutrino-oscillation framework. The combination of this result with the
gadolinium-capture result is also reported.Comment: 26 pages, 23 figure
Optimal Stocking Density for Culturing Tropical Soil-dwelling Earthworm, Pontoscolex corethrurus (Kepadatan Optimum untuk Pengkulturan Cacing Tanah Tropika, Pontoscolex corethrurus)
ABSTRACT The present study was carried out to determine the optimal stocking density for culturing tropica
- …