57 research outputs found
An assessment of energy storage options for large-scale PV-RO desalination in the extended Mediterranean region
Diaminobenzidine photoconversion is a suitable tool for tracking the intracellular location of fluorescently labelled nanoparticles at transmission electron microscopy.
Chitosan-based nanoparticles (NPs) deserve particular attention as suitable drug carriers in the field of pharmaceutics, since they are able to protect the encapsulated drugs and/or improve their efficacy by making them able to cross biological barriers (such as the blood-brain barrier) and reach their intracellular target sites. Understanding the intracellular location of NPs is crucial for designing drug delivery strategies. In this study, fluorescently-labelled chitosan NPs were administered in vitro to a neuronal cell line, and diaminobenzidine (DAB) photoconversion was applied to correlate fluorescence and transmission electron microscopy to precisely describe the NPs intracellular fate. This technique allowed to demonstrate that chitosan NPs easily enter neuronal cells, predominantly by endocytosis; they were found both inside membrane-bounded vesicles and free in the cytosol, and were observed to accumulate around the cell nucleus
Design of epidermal growth factor immobilization on 3D biocompatible scaffolds to promote tissue repair and regeneration
Exogenous application of human epidermal growth factor (hEGF) stimulates epidermal wound healing. The aim of this study was to develop bioconjugates based on hEGF mimicking the protein in its native state and thus suitable for tissue engineering applications, in particular for treating skin-related disorders as burns. Ribonuclease A (RNase A) was used to investigate a number of different activated-agarose carriers: cyanogen bromide (CNBr)-activated-agarose and glyoxyl-agarose showed to preserve the appropriate orientation of the protein for receptor binding. EGF was immobilized on these carriers and immobilization yield was evaluated (100% and 12%, respectively). A peptide mapping of unbound protein regions was carried out by LCâMS to take evidence of the residues involved in the immobilization and, consequently, the flexibility and surface accessibility of immobilized EGF. To assess cell proliferative activities, 10, 25, 50, and 100Â ng/mL of each immobilized EGF sample were seeded on fibroblast cells and incubated for 24, 48 and 72Â h. The immobilized growth factor showed significantly high cell proliferative activity at 50 and 100Â ng/mL compared to control and soluble EGF. Although both of the immobilized samples show dose-dependency when seeded with high number of fibroblast cells, CNBr-agarose-EGF showed a significantly high activity at 100Â ng/mL and 72Â h incubation, compared to glyoxyl-agarose-EGF
Finite volume corrections to the electromagnetic current of the nucleon
We compute corrections to both the isovector anomalous magnetic moment and
the isovector electromagnetic current of the nucleon to in the
framework of covariant two-flavor Baryon Chiral Perturbation Theory. We then
apply these corrections to lattice data for the anomalous magnetic moment from
the LHPC, RBC & UKQCD and QCDSF collaborations
A screening study of the spatial distribution and cumulative toxicity of agricultural pesticides in the European Unionâs waters
Pesticides can be an important stressor to aquatic ecosystems, and their use is strictly regulated in the European Union (EU). However, data on the use of pesticides are rather limited and poorly available, and monitoring is often insufficient to characterize their actual exposure and impact. The aim of the work presented here is to harness the limited data available and assess, for the first time, the distribution of concentrations and toxicity of 148 pesticide active substances (AS) for the whole EU. Starting from available estimates of pesticide use in agriculture and a simple screening-level model of their fate and transport, we quantify pesticide concentrations in soil and water. A comparison with monitoring data shows that predicted water concentrations are in plausible orders of magnitude, hence the model can be regarded as a first-approximation representation of the distribution of pesticides in the environment. The toxicity of individual pesticide active substances (AS) is characterized by their concentrations divided by the respective no observed effect concentrations (NOEC) for aquatic organisms, which represents the âtoxic unitsâ (TU) of each AS. The cumulative toxicity of pesticides in soils and streams of the EU is obtained by summing the TU of individual AS. We estimate that the toxicity of individual AS is generally well below 0.1 TU, indicating relatively safe environmental exposure. However, the cumulative toxicity of a mixture of AS can exceed 0.1 toxic units (TU) for more than 27% of the length of the EUâs stream network, and 1 TU for more than 4%. The cumulative toxicity at a given location is driven by only a handful of AS, but these differ from site to site reflecting the variability of pesticide use. Still, we estimate that only about 20 AS out of 148 appear among the top contributors to cumulative toxicity in most cases. While our assessment suggests a relatively widespread risk due to pesticide pollution, it also points to the important limitations concerning knowledge of pesticide use and monitoring of pesticide occurrence in the environment. These limitations need to be addressed in order to evaluate more accurately the effectiveness of EU pesticide policies. The assessment represents a proof-of-concept of a method that can be applied in support of the monitoring of pesticide policies implementation in the EU and elsewhere, once pesticide use can be estimated
Sigma term and strangeness content of octet baryons
By using lattice QCD computations we determine the sigma terms and
strangeness content of all octet baryons by means of an application of the
Hellmann-Feynman theorem. In addition to polynomial and rational expressions
for the quark mass dependence of octet members, we use SU(3) covariant baryon
chiral perturbation theory to perform the extrapolation to the physical up and
down quark masses. Our N_f=2+1 lattice ensembles include pion masses down to
about 190 MeV in large volumes (M_\pi L > 4), and three values of the lattice
spacing. Our main results are the nucleon sigma term \sigma_{\pi N} =
39(4)(^{+18}_{-7}) and the strangeness content y_{N} = 0.20(7)(^{+13}_{-17}).
Under the assumption of validity of covariant baryon \chi PT in our range of
masses one finds y_{N} = 0.276(77)(^{+90}_{-62}).Comment: LaTeX. 15 pages, 5 figures. Text and results corrected according to
Erratum [Phys. Rev. D 93, 039905(E) (2016)
Generalized Parton Distributions from Hadronic Observables: Non-Zero Skewness
We propose a physically motivated parametrization for the unpolarized
generalized parton distributions, H and E, valid at both zero and non-zero
values of the skewness variable, \zeta. Our approach follows a previous
detailed study of the \zeta=0 case where H and E were determined using
constraints from simultaneous fits of the experimental data on both the nucleon
elastic form factors and the deep inelastic structure functions in the non
singlet sector. Additional constraints at \zeta \neq 0 are provided by lattice
calculations of the higher moments of generalized parton distributions. We
illustrate a method for extracting generalized parton distributions from
lattice moments based on a reconstruction using sets of orthogonal polynomials.
The inclusion in our fit of data on Deeply Virtual Compton Scattering is also
discussed. Our method provides a step towards a model independent extraction of
generalized distributions from the data. It also provides an alternative to
double distributions based phenomenological models in that we are able to
satisfy the polynomiality condition by construction, using a combination of
experimental data and lattice, without resorting to any specific mathematical
construct.Comment: 29 pages, 8 figures; added references, changed text in several place
The first PDF moments for three dynamical flavors in Baryon Chiral Perturbation Theory
We present a calculation of generalized baryon form factors in the framework
of three-flavor covariant baryon chiral perturbation theory at leading one-loop
order. This is needed for lattice calculations of the first moments of
generalized parton distribution functions. The formulae we derive can be used
to guide the chiral extrapolation of such lattice results
Microspheres prepared with biodegradable PHBV and PLA polymers as prolonged-release system for ibuprofen: in vitro drug release and in vivo evaluation
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