1,740 research outputs found
Exploración clÃnica en estomatologÃa veterinaria
La exploración clÃnica se basa en un conjunto de normas y maniobras encaminadas al estudio de sÃntomas para la determinación diagnóstica de patologÃas, y al establecimiento de un tratamiento adecuado y especÃfico. Explicamos la exploración sistemática que debe ponerse en práctica en el campo de la EstomatologÃa Veterinaria, pudiendo asà determinar las afecciones de los tejidos blandos y duros.For the diagnostic of different oral pathologies we use several techniques. We will establish a specific treatment for each one. We describe a sistemic exploration that is used in veterinary dentistry and afecting both, soft and hard tissues
Innovative approach for producing injectable, biodegradable materials using chitooligosaccharides and green chemistry
Although there are a number of injectable biomaterials currently under development, they present some drawbacks
such as being based on synthetic polymers, needing toxic or aggressive synthesis procedures or using raw materials
with low availability and/or high production costs. Having this in mind, a novel injectable biomaterial using
chitooligosaccharides as starting materials was developed. This system uses a widely available and cheap polymer
from marine biomass (chitosan), which can be turned into an injectable material by water-based and ecologically
friendly reactions. Chitooligosaccharides were functionalized with methacrylic groups, to allow in situ crosslinking.
The degree of substitution, as determined by 1H NMR, varied between 5 and 50%. The system was
characterized in terms of kinetics of gel formation, rheology, degradation behavior and in vitro cytotoxicity. The
gelation time could be easily tailored between 1.5 and 60 min by changing the conditions of the methacrylation
reaction, and the final gel presented rheological properties typical of strong gels, that is, shear stresses in the kPa
range. The cross-linked gel was degradable and nontoxic, presenting indeed an interesting cytokinetic effect.
Injectable materials based on chitooligosaccharides are, therefore, an innovative system combining adequate
biological performance, ease of preparation, and an ecologically friendly concept of production.The authors thank Dr. Mar Fernandez for the cytotoxicity tests. L.F.B. thanks the European Commission for supporting this work through a Marie Curie-IIF fellowship
Injectable hydrogels based on chitosan
Oligo-D-glucosamine (‘‘oligomer’’ of chitosan) seems well suited for injectable, biodegradable systems (IBS), due to their solubility in water, easier funtionalization and the possibility of working at
high concentrations. Chitosan was enzymatically degraded with a commercial enzyme (Multifect Pectinase FE) at 508C and pH 5.5 during 17h, adapting a previous procedure. The oligomers were precipitated in ethanol and analysed by MALDI-TOF/MS and FTIR. They were then functionalized by reaction with methacrylic anhydride (MethA), varying ratio of amount of substance of MethA : amount of substance of -NH2 groups in the oligomer. The obtained methacrylamide-
oligomers were polymerized with a potassium persulfate/ vitamin C initiation system. Both the modified oligomers and the polymerized product were analysed by FTIR and NMR. [...]info:eu-repo/semantics/publishedVersio
Spatial partial coherence in Young's interferograms
Young's interferograms with high visibility reveals a high degree of spatial coherence of first order. But, spatially partial coherence of second order can be observed when it interferes itself through a compensated Michelson's interferometer attached at the exit of the Young's slit pair. We show that the patterns at the exit of the Michelson's interferometer are Young's interferograms with modulation fringes, which allow an estimation of the degree of the high order spatial coherence
Contraindicaciones y complicaciones más frecuentes en las técnicas endodónticas
En el trabajo se exponen las diferentes circunstancias en las que la aplicación de las técnicas endodónticas están contraindicadas. Causas de orden general y de orden local que no aconsejan la realización de la terapia, asà como casos dudosos en los que se deben poner en práctica técnicas alternativas o tratamientos que nos posibiliten el posterior desarrollo de la endodoncia.The contraindications of endodontic techniques are exposed in this work. Tbey bave a general or local origen. In the doubt cases an alternative treatment bave to be develop before the endodontic technique has been made
Spectroscopic characterisation of the stellar content of ultra diffuse galaxies
Understanding the peculiar properties of Ultra Diffuse Galaxies (UDGs) via
spectroscopic analysis is a challenging task requiring very deep observations
and exquisite data reduction. In this work we perform one of the most complete
characterisations of the stellar component of UDGs to date using deep optical
spectroscopic data from OSIRIS at GTC. We measure radial and rotation
velocities, star formation histories (SFH) and mean population parameters, such
as ages and metallicities, for a sample of five UDG candidates in the Coma
cluster. From the radial velocities, we confirm the Coma membership of these
galaxies. We find that their rotation properties, if detected at all, are
compatible with dwarf-like galaxies. The SFHs of the UDG are dominated by old
(~ 7 Gyr), metal-poor ([M/H] ~ -1.1) and alpha-enhanced ([Mg/Fe] ~ 0.4)
populations followed by a smooth or episodic decline which halted ~ 2 Gyr ago,
possibly a sign of cluster-induced quenching. We find no obvious correlation
between individual SFH shapes and any UDG morphological properties. The
recovered stellar properties for UDGs are similar to those found for DDO44, a
local UDG analogue resolved into stars. We conclude that the UDGs in our sample
are extended dwarfs whose properties are likely the outcome of both internal
processes, such as bursty SFHs and/or high-spin haloes, as well as
environmental effects within the Coma cluster.Comment: Accepted for publication in MNRA
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