217 research outputs found
Quantum key distribution session with 16-dimensional photonic states
The secure transfer of information is an important problem in modern
telecommunications. Quantum key distribution (QKD) provides a solution to this
problem by using individual quantum systems to generate correlated bits between
remote parties, that can be used to extract a secret key. QKD with
D-dimensional quantum channels provides security advantages that grow with
increasing D. However, the vast majority of QKD implementations has been
restricted to two dimensions. Here we demonstrate the feasibility of using
higher dimensions for real-world quantum cryptography by performing, for the
first time, a fully automated QKD session based on the BB84 protocol with
16-dimensional quantum states. Information is encoded in the single-photon
transverse momentum and the required states are dynamically generated with
programmable spatial light modulators. Our setup paves the way for future
developments in the field of experimental high-dimensional QKD.Comment: 8 pages, 3 figure
Antitumoral properties of two new vanadyl(IV) complexes in osteoblasts in culture: role of apoptosis and oxidative stress
Background: Vanadium derivatives have been reported to display different biological effects, and in particular antineoplastic activity has been demonstrated in both in vivo and in vitro studies.
Purpose:To study the effect of two new organic vanadyl(IV) complexes (one with glucose, GluVO, and the other with naproxen, NapVO) in osteosarcoma cells.
Methods:UMR106 osteosarcoma cells and, for comparison, nontransformed MC3T3E1 osteoblasts were used.
Proliferation and differentiation were assessed using the crystal violet assay and ALP specific activity, respectively. Morphological alterations were assessed by light microscopy. Lipid peroxidation was evaluated in terms of production of thiobarbituric acid-reactive substances (TBARS) and apoptosis was measured using annexin V. Extracellular regulated kinase (Erk) activation was investigated by Western blotting.
Results:Vanadium complexes caused morphological alterations and they strongly inhibited UMR106 cell proliferation and differentiation. In contrast, in MC3T3E1 cells, these vanadium derivatives had a relatively weak action. In UMR106 tumoral cells there was a significant increase in TBARS production. Both vanadium complexes induced apoptosis and activation of Erk. PD98059, an inhibitor of Erk phosphorylation, did not block the vanadium-induced antitumoral action.
However, the antioxidants vitamins C and E abrogated the apoptosis and TBARS production induced by the vanadium complexes.
Conclusions:GluVO and NapVO exerted an antitumoral effect in UM106 osteosarcoma cells. They inhibited cell proliferation and differentiation. While the Erk cascade seems not to be directly related to the bioactivity of these vanadium derivatives, the action of both vanadium complexes with organic ligands may be mediated by apoptosis and oxidative stress
La libertad civil como condición de posibilidad de la autonomía moral: sobre la aportación de Freud al planteamiento práctico de Kant
Metallic ions as therapeutic agents in tissue engineering scaffolds: an overview of their biological applications and strategies for new developments
This article provides an overview on the application of metallic ions in the fields of regenerative medicine and tissue engineering, focusing on their therapeutic applications and the need to design strategies for controlling the release of loaded ions from biomaterial scaffolds. A detailed summary of relevant metallic ions with potential use in tissue engineering approaches is presented. Remaining challenges in the field and directions for future research efforts with focus on the key variables needed to be taken into account when considering the controlled release of metallic ions in tissue engineering therapeutics are also highlighted
Genetic and Physiological Analysis of Iron Biofortification in Maize Kernels
BACKGROUND: Maize is a major cereal crop widely consumed in developing countries, which have a high prevalence of iron (Fe) deficiency anemia. The major cause of Fe deficiency in these countries is inadequate intake of bioavailable Fe, where poverty is a major factor. Therefore, biofortification of maize by increasing Fe concentration and or bioavailability has great potential to alleviate this deficiency. Maize is also a model system for genomic research and thus allows the opportunity for gene discovery. Here we describe an integrated genetic and physiological analysis of Fe nutrition in maize kernels, to identify loci that influence grain Fe concentration and bioavailability. METHODOLOGY: Quantitative trait locus (QTL) analysis was used to dissect grain Fe concentration (FeGC) and Fe bioavailability (FeGB) from the Intermated B73 × Mo17 (IBM) recombinant inbred (RI) population. FeGC was determined by ion coupled argon plasma emission spectroscopy (ICP). FeGB was determined by an in vitro digestion/Caco-2 cell line bioassay. CONCLUSIONS: Three modest QTL for FeGC were detected, in spite of high heritability. This suggests that FeGC is controlled by many small QTL, which may make it a challenging trait to improve by marker assisted breeding. Ten QTL for FeGB were identified and explained 54% of the variance observed in samples from a single year/location. Three of the largest FeGB QTL were isolated in sister derived lines and their effect was observed in three subsequent seasons in New York. Single season evaluations were also made at six other sites around North America, suggesting the enhancement of FeGB was not specific to our farm site. FeGB was not correlated with FeGC or phytic acid, suggesting that novel regulators of Fe nutrition are responsible for the differences observed. Our results indicate that iron biofortification of maize grain is achievable using specialized phenotyping tools and conventional plant breeding techniques
Intracellular Serotonin Modulates Insulin Secretion from Pancreatic β-Cells by Protein Serotonylation
Non-neuronal, peripheral serotonin deficiency causes diabetes mellitus and identifies an intracellular role for serotonin in the regulation of insulin secretion
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