3,527 research outputs found
Regulatory parameters of self-healing alginate hydrogel networks prepared via mussel-inspired dynamic chemistry
Several key parameters that influence both the self-healing properties and water retention capacity of biohydrogel networks made of alginate-dopamine (Alg-DA) conjugates have been studied. A judicious combination of biopolymer concentration, dopamine content, pH-dependent cross-linking of catechol groups and the Fe3+-coordination of the networks allowed control over the self-healing ability of these bioinspired materials. Moreover, the thixotropic nature of model hydrogels was confirmed using oscillatory rheological loop tests
DNA-catalyzed Henry Reaction in Pure Water and the Striking Influence of Organic Buffer Systems
In this manuscript we report a critical evaluation of the ability of natural DNA to mediate the nitroaldol (Henry) reaction at physiological temperature in pure water. Under these conditions, no background reaction took place (i.e., control experiment without DNA). Both heteroaromatic aldehydes (e.g., 2-pyridinecarboxaldehyde) and aromatic aldehydes bearing strong or moderate electron-withdrawing groups reacted satisfactorily with nitromethane obeying first order kinetics and affording the corresponding β-nitroalcohols in good yields within 24 h. In contrast, aliphatic aldehydes and aromatic aldehydes having electron-donating groups either did not react or were poorly converted. Moreover, we discovered that a number of metal-free organic buffers efficiently promote the Henry reaction when they were used as reaction media without adding external catalysts. This constitutes an important observation because the influence of organic buffers in chemical processes has been traditionally underestimated
The incorporation of alpha-tocopherol and functional doses of phytosterol esters during cheesemaking does not affect DNA or mRNA dynamics of Streptococcus thermophilus and Lactococcus lactis throughout and after the end of ripening
Tocopherols and phytosterols are lipid-soluble molecules which have been widely used in the food industry. Nevertheless, the influence of these compounds on the performance of starter lactic acid bacteria (SLAB) in fermented foods has received little attention. Here, we assessed the behavior of Streptococcus thermophilus and Lactococcus lactis during the ripening of a functional Port Salut light cheese elaborated with these SLAB and with alpha-tocopherol and phytosterol esters as bioactive molecules. Functional and control cheeses were manufactured at an industrial plant and sampled at 7, 21, 40, 60 and 90 days after elaboration for real-time quantitative PCR (qPCR) or reverse transcription-qPCR (RT-qPCR) experiments. Target DNA and mRNA from both SLAB were detected after 90 days of elaboration in both functional and control cheeses, supporting their potential role in generating flavor metabolites. Furthermore, here we showed for the first time that the addition of alpha-tocopherol and functional doses of phytosterols did not affect DNA or mRNA dynamics of these SLAB during cheesemaking, throughout and after the end of ripening. Therefore, our results support the use of cheese manufactured with both S. thermophilus and L. lactis as an optimal delivery system for these beneficial bioactive compounds.Fil: Pega, Juan Franco. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Pérez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Rizzo, Sergio Anibal. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Rossetti, Luciana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Diaz, G.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Ruzal, Sandra Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nanni, M.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Descalzo, Adriana Maria. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; Argentina. Centre de Coopération Internationale en Recherche Agronomique pour le Développerment; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
The Orbit of the New Milky Way Globular Cluster FSR1716 =VVV-GC05
Indexación: Scopus.We use deep, multi-epoch near-IR images of the VISTA Variables in the Via Lictea (VVV) Survey to measure proper motions (PMs) of stars in the Milky Way globular cluster (GC) FSR1716 = VVV-GC05. The colormagnitude diagram of this object, made by using PM-selected members, shows an extended horizontal branch, nine confirmed RR Lyrae (RRL) members in the instability strip, and possibly several hotter stars extending to the blue. Based on the fundamental-mode (ab-type) RRL stars that move coherently with the cluster, we confirmed that FSR1716 is an Oosterhoff I GC with a mean period aPabn = 0.574 days. Intriguingly, we detect tidal extensions to both sides of this cluster in the spatial distribution of PM-selected member stars. Also, one of the confirmed RRabs is located -11 arcmin in projection from the cluster center, suggesting that FSR1716 may be losing stars due to the gravitational interaction with the Galaxy. We also measure radial velocities (RVs) for five cluster red giants selected using the PMs. The combination of RVs and PMs allow us to compute for the first time the orbit of this GC, using an updated Galactic potential. The orbit results to be confined within|Zmax| < 2.0 kpc, and has eccentricity 0.4 < e < 0.6, with perigalactic distance 1.5 < Rperi (kpc) < 2.3, and apogalactic distance 5.3 < Rapo (kpc) < 6.4. We conclude that, in agreement with its relatively low metallicity ([Fe/H] =-1.4 dex), this is an inner-halo GC plunging into the disk of the Galaxy. As such, this is a unique object with which to test the dynamical processes that contribute to the disruption of Galactic GCs. © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-4357/aacd0
Psoriatic Animal Models Developed for the Study of the Disease
Psoriasis is a skin disease mainly developed in humans, although it is also seen in monkeys and dogs. Animal models with psoriasis-like lesions have been a key factor for its understanding. Xenotransplants of human psoriatic skin in immunodeficient mice were the first approach for the association of immunologic problems with the development of psoriasis and have been also useful for the evaluation on new therapeutic agents. Imiquimod-induced murine psoriasis is nowadays one of the most used animal models to study this disease, perhaps because healthy wild-type mice are used, which means that it is an affordable model, easy to generate, and, more importantly, resembles the inflammatory, angiogenic and hyperproliferative characteristics of human psoriasis. Several transgenic (over-expressing VEGF, Tie2, TGFβ, STAT3, IL-36, PPARβ/γ) and knockout (lacking IκBα, JunB, IFNR-2, IL-36RA, CD18, IKK2) mice have been useful for the association of specific molecules for the development of psoriasis. Other approach has been the use of both transgenic/knockout mice and imiquimod treatment, where the importance of βTrCP, IκBζ, IL-35 and Tnip1 for the development of psoriasis was found. In this chapter, some of these animal models are discussed
Friedel Oscillations in Relativistic Nuclear Matter
We calculate the low-momentum N-N effective potential obtained in the OBE
approximation, inside a nuclear plasma at finite temperature, as described by
the relativistic - model. We analyze the screening effects
on the attractive part of the potential in the intermediate range as density or
temperature increase. In the long range the potential shows Friedel-like
oscillations instead of the usual exponential damping. These oscillations arise
from the sharp edge of the Fermi surface and should be encountered in any
realistic model of nuclear matter.Comment: 11 pages in preprint format, typeset using REVTEX, 3 included figures
in tar, compressed, uuencoded forma
Análisis y distribución de hidrocarburos policíclicos aromáticos (PAH's) en suelos y aguas de escombreras en Puertollano (Ciudad Real)
The aim of this study was to examine if the soils and waters of Puertollano area are affected by pollution of polycyclic aromatic hydrocarbons (PAHs) and their quantification. The results show that PAHs concentrations are higher in all samples than the reference levels gathered in the Spanish legislation. The possible actions for the coal waste remediation (re-wash of waste dumps, photodegradation and biorremediation) seems to be unviable in this case because of the large volume of materials affected, the slowness of these processes, and the geomorphological characteristics of the carboniferous Puertollano basin. During the spatial regional planning, maps showing the concentration of PAHs should be made to adapt the soil for its corresponding use. It is proposed to consider as contaminants more PAHs, such as naftalene or fluorantene in waters, and phenanthrene and benzo[ghi] perilene in soils
Preparation and characterization of phosphorus-containing electrocatalyst for OER, HER and ORR.
Phosphorus-based materials, such as transition metal phosphides and phosphates/pyrophosphates, have drawn considerable attention as promising alternatives to noble metal-based catalysts (Pt, Ru, Ir) owing to their widely tunable electrocatalytic properties.
In this work, we propose the preparation of electrocatalysts using metal phosphonates of composition M(O3PCH(OH)COOH)·2H2O (M2+= Mn, Fe, Co, and Ni) as precursors. The electrocatalysts were obtained by pyrolytic treatments (N2 or 5%H2-Ar atmospheres) giving rise to a wide family of crystalline and amorphous metal pyrophosphates and phosphides. The full-characterised solids by XRD (laboratory and synchrotron), TEM and XPS were then assayed as catalysts for Oxygen Evolution Reaction (OER), Oxygen Reduction Reaction (ORR) and Hydrogen Evolution Reaction (HER). The amorphous iron(II)-doped cobalt pyrophosphate and crystalline phosphides (MP and/or M2P; and M2+= Co, Ni) exhibited the best performances and long-times stabilities. On the other hand, pair distribution function (PDF) studies, using synchrotron radiation, and XPS analysis reveal that the amorphous/crystalline phases are stable for the HER and ORR processes, while solids evolve to other active phases, such as (oxy)hydroxides, upon conducting the OER. The performance of selected electrocatalysts has been tested for H2 production and monitored by laboratory X-ray computed nanotomography (nanoCT).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Impulsive generation of 100 dislocation loops in BCC iron
The conditions for the formation of 100 dislocation loops in body-centered cubic (BCC) iron were investigated via molecular dynamics simulations using a simplified model intended to mimic conditions in high energy collision cascades, focusing on the possible coherent displacement of atoms at the boundary of a subcascade. We report on the formation of 100 dislocation loops due to the fast displacement of a few hundred atoms with a coherent acceleration, in agreement with previous results for much larger cascade simulations. We analyze in detail the resulting atomic velocities and pressures, and find that they cannot be described within the usual formalism for a shock regime, since the pressure pulse only lasts less than 1 ps and does not match expected values from a Hugoniot shock. Our simulations include two interatomic potentials: Mendelev, which is extensively used for radiation damage simulations, and Ackland, which has been used for shock simulations because it can reproduce the experimentally observed transition from BCC to hexagonal close-packed structure at around 25 GPa, at high deformation rates. They both show similar evolution of defects, also indicating departure from a shock regime which is extremely different for these potentials.Fil: Bertoni, Andrés Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Deluigi, Orlando Raul. Universidad de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Dos Santos Mendez, Gonzalo Joaquín. Universidad de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Pérez Diaz, M.. Universidad Nacional de Cuyo; ArgentinaFil: Bringa, Eduardo Marcial. Universidad Mayor; Chile. Universidad de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin
Supersymmetry for Fermion Masses
It is proposed that supersymmetry (SUSY) maybe used to understand fermion
mass hierarchies. A family symmetry Z_{3L} is introduced, which is the cyclic
symmetry among the three generation SU(2) doublets. SUSY breaks at a high
energy scale ~ 10^{11} GeV. The electroweak energy scale ~ 100 GeV is
unnaturally small. No additional global symmetry, like the R-parity, is
imposed. The Yukawa couplings and R-parity violating couplings all take their
natural values which are about (10^0-10^{-2}). Under the family symmetry, only
the third generation charged fermions get their masses. This family symmetry is
broken in the soft SUSY breaking terms which result in a hierarchical pattern
of the fermion masses. It turns out that for the charged leptons, the tau mass
is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the
muon mass is due to the sneutrino VEVs, and the electron gains its mass due to
both Z_{3L} and SUSY breaking. The large neutrino mixing are produced with
neutralinos playing the partial role of right-handed neutrinos. |V_{e3}| which
is for nu_e-nu_{tau} mixing is expected to be about 0.1. For the quarks, the
third generation masses are from the Higgs VEVs, the second generation masses
are from quantum corrections, and the down quark mass due to the sneutrino
VEVs. It explains m_c/m_s, m_s/m_e, m_d > m_u and so on. Other aspects of the
model are discussed.Comment: 25 pages, 3 figures, revtex4; neutrino oscillation and many
discussions added, smallness of the electron mass due to supersymmetry
pointed out; v3: numerical errors correcte
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