1,088 research outputs found

    An Overview of Poly(lactic-co-glycolic) Acid (PLGA)-Based Biomaterials for Bone Tissue Engineering

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    Poly(lactic-co-glycolic) acid (PLGA) has attracted considerable interest as a base material for biomedical applications due to its: (i) biocompatibility; (ii) tailored biodegradation rate (depending on the molecular weight and copolymer ratio); (iii) approval for clinical use in humans by the U.S. Food and Drug Administration (FDA); (iv) potential to modify surface properties to provide better interaction with biological materials; and (v) suitability for export to countries and cultures where implantation of animal-derived products is unpopular. This paper critically reviews the scientific challenge of manufacturing PLGA-based materials with suitable properties and shapes for specific biomedical applications, with special emphasis on bone tissue engineering. The analysis of the state of the art in the field reveals the presence of current innovative techniques for scaffolds and material manufacturing that are currently opening the way to prepare biomimetic PLGA substrates able to modulate cell interaction for improved substitution, restoration, or enhancement of bone tissue function

    Engineering cartilage like tissue using polymeric systems derived from 2-ethyl-2-pyrrolidone-methacrylate combined with hyaluronic acid

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    Hydrogels are potential candidates for Tissue engineering (TE), because of their water content, transport properties, and tissue like physical and chemical behaviour. This project was based on the production and characterization of implantable stimuli responsive scaffolds made of hyaluronic acid (HA) that presents a high water retention character, in combination with 2-ethyl (2-pyrrolidone) methacrylate (EPM), possessing temperature-dependent solubility in water, by bulk polymerization. [...]info:eu-repo/semantics/publishedVersio

    The mental health and well-being of adolescents with/without intellectual disability in the UK

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    Aims To estimate the self-reported and parent-reported mental well-being of adolescents (aged 14 and 17) with/without intellectual disability in a sample of young people representative of the UK population.MethodsSecondary analysis of data collected in Waves 6 and 7 of the UK's Millennium Cohort Study. The analytic sample consisted of 10,838 adolescent respondents at age 14 (361 with intellectual disability and 10,477 without) and 9,408 adolescent respondents at age 17 (292 with intellectual disability and 9,116 without).ResultsParental reports of adolescent problems on the Strengths and Difficulties Questionnaire (SDQ) indicated that adolescents with intellectual disability at ages 14 and 17 were more likely to have problems than those without intellectual disability across all SDQ domains. Adolescent self-report data at age 17 indicated that adolescents with intellectual disability were more likely to (self)-report that they had problems than those without intellectual disability on all but one SDQ domain. The magnitude of relative inequality between those with and without intellectual disability was consistently lower for self-report than parental report. On indicators of depression, mental well-being, self-harm, positive mental health, happiness and general psychological distress at ages 14 and 17, we found no self-reported group differences between adolescents with and without intellectual disability.ConclusionsFurther research is needed to understand: (1) why the magnitude of mental health inequalities between those with and without intellectual disability on the SDQ may be dependent on the identity of the informant; and (2) whether such differences are also apparent for other measures of mental health or well-being

    Complexity reduction and policy consensus: asylum seekers, the right to work, and the ‘pull factor’ thesis in the UK context

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    Since the early 2000s, asylum policy in Western states has become increasingly dominated by the concept of the ‘pull factor’—the idea that the economic rights afforded to asylum seekers can act as a migratory pull, and will have a bearing on the numbers of asylum applications received. The pull factor thesis has been widely discredited by researchers but remains powerful among policymakers. Through an analysis of the pull factor in the UK context, and drawing on insights from Cultural Political Economy, this article argues that the hegemony of the pull factor thesis is best understood as a ‘policy imaginary’ which has become sedimented through both discursive and extra-discursive practices and processes. The article offers a means of understanding how a common sense assumption—which is challenged by a large body of evidence—has come to dominate policymaking in a key area of concern for politicians and policymakers

    The evolution of galaxy groups and of galaxies therein

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    Properties of groups of galaxies depend sensitively on the algorithm for group selection, and even the most recent catalogs of groups built from redshift-space selection should suffer from projections and infalling galaxies. The cosmo-dynamical evolution of groups from initial Hubble expansion to collapse and virialization leads to a fundamental track (FT) in virial-theorem-M/L vs crossing time. The increased rates of mergers, both direct and after dynamical friction, in groups relative to clusters, explain the higher fraction of elliptical galaxies at given local number density in X-ray selected groups, relative to clusters, even when the hierarchical evolution of groups is considered. Galaxies falling into groups and clusters should later travel outwards to typically 2 virial radii, which is somewhat less than the outermost radius where observed galaxy star formation efficiencies are enhanced relative to field galaxies of same morphological type. An ongoing analysis of the internal kinematics of X-ray selected groups suggests that the radial profiles of line of sight velocity dispersion are consistent with isotropic NFW distributions for the total mass density, with higher (lower) concentrations than LambdaCDM predictions in groups of high (low) mass. The critical mass, at M200 ~ 10^13 M_sun is consistent with possible breaks in the X-ray luminosity-temperature and Fundamental Plane relations. The internal kinematics of groups indicate that the M-T relation of groups should agree with that extrapolated from clusters with no break at the group scale. The analyses of observed velocity dispersion profiles and of the FT both suggest that low velocity dispersion groups (compact and loose, X-ray emitting or undetected) are quite contaminated by chance projections.Comment: Invited review, ESO workshop "Groups of Galaxies in the Nearby Universe", held in Santiago, Chile, 5-9 December 2005, ed. I. Saviane, V. Ivanov & J. Borissova, 16 page

    Commissioning of the CMS High Level Trigger

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    The CMS experiment will collect data from the proton-proton collisions delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to 14 TeV. The CMS trigger system is designed to cope with unprecedented luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger architecture only employs two trigger levels. The Level-1 trigger is implemented using custom electronics, while the High Level Trigger (HLT) is based on software algorithms running on a large cluster of commercial processors, the Event Filter Farm. We present the major functionalities of the CMS High Level Trigger system as of the starting of LHC beams operations in September 2008. The validation of the HLT system in the online environment with Monte Carlo simulated data and its commissioning during cosmic rays data taking campaigns are discussed in detail. We conclude with the description of the HLT operations with the first circulating LHC beams before the incident occurred the 19th September 2008

    The VIMOS VLT Deep Survey: The build-up of the colour-density relation

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    We investigate the redshift and luminosity evolution of the galaxy colour-density relation using the data from the First Epoch VIMOS-VLT Deep Survey (VVDS). The size (6582 galaxies), depth (I_AB<=24) and redshift sampling rate of the survey enable us to reconstruct the 3D galaxy environment on relatively local scales (R=5 Mpc) up to z~1.5. Particular attention has been devoted to calibrate a density reconstruction scheme, which factors out survey selection effects and reproduces in an unbiased way the underlying `real' galaxy environment. While at lower redshift we confirm the existence of a steep colour-density relation, with the fraction of the reddest(/bluest) galaxies of the same luminosity increasing(/decreasing) as a function of density, this trend progressively disappears in the highest redshift bins investigated. The rest frame u*-g' colour-magnitude diagram shows a bimodal pattern in both low and high density environments up to z~1.5. We find that the bimodal distribution is not universal but strongly depends upon environment: at lower redshifts the colour-magnitude diagrams in low and high density regions are significantly different while the progressive weakening of the colour-density relation causes the two bimodal distributions to nearly mirror each other in the highest redshift bin investigated. Both the colour-density and the colour-magnitude-density relations appear to be a transient, cumulative product of genetic and environmental factors operating over at least a period of 9 Gyr. These findings support an evolutionary scenario in which star formation/gas depletion processes are accelerated in more luminous objects and in high density environments: star formation activity is shifting with cosmic time towards lower luminosity (downsizing), and out of high density environments.Comment: 17 pages, 10 figures, figures added, accepted by A&
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