770 research outputs found

    Diagnostic Problem Solving in Male Collegiate Athletic Trainers

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    Context: Knowledge and experience may be important factors for understanding expertise based upon a clinician\u27s ability to select and execute an appropriate response as a clinician during injury evaluation. Objective: To describe how collegiate male certified athletic trainers represent injury-evaluation domain knowledge during a situational interview using a think-aloud protocol. Design: Qualitative. Setting: National Collegiate Athletic Association Division I and II colleges in National Athletic Trainers\u27 Association District 3. Patients or Other Participants: A total of 20 male certified athletic trainers (n = 10 with less than 2 years of experience in the college setting and n = 10 with at least 10 years of experience in the college setting) participated in the study. Data Collection and Analysis: We collected data using a situational interview and questionnaire. Data were transcribed, reduced to meaningful units, and analyzed using verbal analysis procedures. Member checks, triangulation of data, field journaling, and peer-debriefing techniques were used to ensure trustworthiness of the data. Knowledge concepts were enumerated to describe differences between experts and novices. Results: Compared with novices, experts had more knowledge concepts of patient history and predictions and fewer concepts of situation appraisal. Conclusions: Expertise in athletic training shares traits with other areas in health care. Athletic training education and professional development may benefit from our understanding which cognitive processes differentiate expert practice. Future investigators should attempt to describe other settings and study diagnostic problem solving in a natural environment

    Graphene-based nanomaterials for tissue engineering in the dental field

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    The world of dentistry is approaching graphene-based nanomaterials as substitutes for tissue engineering. Apart from its exceptional mechanical strength, electrical conductivity and thermal stability, graphene and its derivatives can be functionalized with several bioactive molecules. They can also be incorporated into different scaffolds used in regenerative dentistry, generating nanocomposites with improved characteristics. This review presents the state of the art of graphene-based nanomaterial applications in the dental field. We first discuss the interactions between cells and graphene, summarizing the available in vitro and in vivo studies concerning graphene biocompatibility and cytotoxicity. We then highlight the role of graphene-based nanomaterials in stem cell control, in terms of adhesion, proliferation and differentiation. Particular attention will be given to stem cells of dental origin, such as those isolated from dental pulp, periodontal ligament or dental follicle. The review then discusses the interactions between graphene-based nanomaterials with cells of the immune system; we also focus on the antibacterial activity of graphene nanomaterials. In the last section, we offer our perspectives on the various opportunities facing the use of graphene and its derivatives in associations with titanium dental implants, membranes for bone regeneration, resins, cements and adhesives as well as for tooth-whitening procedure

    Controlling Exchange Pathways in Dynamic Supramolecular Polymers by Controlling Defects

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    Supramolecular fibers composed of monomers that self-assemble directionally via noncovalent interactions are ubiquitous in nature, and of great interest in chemistry. In these structures, the constitutive monomers continuously exchange in-and-out the assembly according to a well-defined supramolecular equilibrium. However, unraveling the exchange pathways and their molecular determinants constitutes a nontrivial challenge. Here, we combine coarse-grained modeling, enhanced sampling, and machine learning to investigate the key factors controlling the monomer exchange pathways in synthetic supramolecular polymers having an intrinsic dynamic behavior. We demonstrate how the competition of directional vs. nondirectional interactions between the monomers controls the creation/annihilation of defects in the supramolecular polymers, from where monomers exchange proceeds. This competition determines the exchange pathway, dictating whether a fiber statistically swaps monomers from the tips or from all along its length. Finally, thanks to their generality, our models allow the investigation of molecular approaches to control the exchange pathways in these dynamic assemblies

    Microlasers based on effective index confined slow light modes in photonic crystal waveguides

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    We present the design, theory and experimental implementation of a low modal volume microlaser based on a line-defect 2D-photonic crystal waveguide. The lateral confinement of low-group velocity modes is controlled by the post-processing of 1 to 3μm wide PMMA strips on top of two dimensional photonic crystal waveguides. Modal volume around 1.3 (λ/n)3can be achieved using this scheme. We use this concept to fabricate microlaser devices from an InP-based heterostructure including InAs0.65P0.35quantum wells emitting around 1550nm and bonded onto a fused silica wafer. We observe stable, room-temperature laser operation with an effective lasing threshold around 0.5mW. © 2008 Optical Society of America

    Avaliação econômica dos sistemas de produção de morango: convencional, integrado e orgânico.

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    Hyperbaric oxygen therapy improves the osteogenic and vasculogenic properties of mesenchymal stem cells in the presence of inflammation in vitro

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    Hyperbaric oxygen (HBO) therapy has been reported to be beneficial for treating many conditions of inflammation-associated bone loss. The aim of this work was to in vitro investigate the effect of HBO in the course of osteogenesis of human Mesenchymal Stem Cells (MSCs) grown in a simulated pro-inflammatory environment. Cells were cultured with osteogenic differentiation factors in the presence or not of the pro-inflammatory cytokine Tumor Necrosis Factor-α (TNF-α), and simultaneously exposed daily for 60 min, and up to 21 days, at 2,4 atmosphere absolute (ATA) and 100% O2. To elucidate osteogenic differentiation-dependent effects, cells were additionally pre-committed prior to treatments. Cell metabolic activity was evaluated by means of the MTT assay and DNA content quantification, whereas osteogenic and vasculogenic differentiation was assessed by quantification of extracellular calcium deposition and gene expression analysis. Metabolic activity and osteogenic properties of cells did not differ between HBO, high pressure (HB) alone, or high oxygen (HO) alone and control if cells were pre-differentiated to the osteogenic lineage. In contrast, when treatments started contextually to the osteogenic differentiation of the cells, a significant reduction in cell metabolic activity first, and in mineral deposition at later time points, were observed in the HBO-treated group. Interestingly, TNF-α supplementation determined a significant improvement in the osteogenic capacity of cells subjected to HBO, which was not observed in TNF-α-treated cells exposed to HB or HO alone. This study suggests that exposure of osteogenic-differentiating MSCs to HBO under in vitro simulated inflammatory conditions enhances differentiation towards the osteogenic phenotype, providing evidence of the potential application of HBO in all those processes requiring bone regeneration

    Traditional landscape and rural development: comparative study in three terraced areas in northern, central and southern Italy to evaluate the efficacy of GAEC standard 4.4 of cross compliance

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    The recent National Strategic Plan 2007-2013 has introduced landscape as a strategic objective of the rural sector. This represents a minor revolution in the way of visualizing the role of the landscape, together with that of agriculture and the rural territory as a whole, and demonstrates the importance of treating the landscape with a systematic point of view. As part of the Efficond project, three sample areas have been identified, each of about 800-1000 hectares, in zones with important historical - cultural landscapes that are included in the National Catalogue of Historical Rural Landscapes. For each sample area a methodology has been applied, defined Historical Cultural Evaluation Approach, developed as part of a project for the monitoring of the Tuscan landscape that we have simplified and adapted. This methodology is based on the consideration that the landscape is the result of the centuries-old interaction between man and the environment, and so to define an element of the landscape as characteristic it is necessary to evaluate the land use dynamics and landscape changes that took place in the past, identifying those that have persisted for a long time, are slowly evolving or stabilized. The study of the historical landscape, which in the proposed methodology refers to the 50’s, has been done through the interpretation and analysis of aerial photographs taken on the GAI flight in 1954, and has allowed the characteristic, traditional and historical elements of that landscape to be identified and an insight to be gained into the cultural identity of the area. Through the creation of specific indices of density and intensity of the terracing obtained by photo-interpretation, field surveys and GIS elaborations, it was possible to classify the sample areas for this specific and important landscape element, compare the results in two periods and evaluate their frequency in the territory. Multi-temporal comparative analysis is being used increasingly often, especially for the study of territories of value, and in our case has been accompanied both by mapping of the landscape dynamics, which identifies the areas subject to transformations in the considered period, and by tables and figures that allow the evolution of a unit of land use to be followed, observing how this has evolved over time. The evaluation of these evolutionary dynamics has then been integrated with a set of indices, in part borrowed from landscape ecology, and in part specifically developed for areas historically shaped by man, which demonstrate that the landscape has become less fragmented and that the layout of fields has been adapted to a different agricultural model that has profoundly changed the structure of the traditional landscape. The efficacy of the laws protecting the characteristic elements of the landscape is strictly linked to the maintenance of its diversity and typicality and conservation of the complexity of the landscape mosaic. Its evaluation necessitates a historical analysis of the evolutionary dynamics conducted at a purely local level

    Study of the impact of tissue density heterogeneities on 3-dimensional abdominal dosimetry: comparison between dose kernel convolution and direct monte carlo methods.

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    Dose kernel convolution (DK) methods have been proposed to speed up absorbed dose calculations in molecular radionuclide therapy. Our aim was to evaluate the impact of tissue density heterogeneities (TDH) on dosimetry when using a DK method and to propose a simple density-correction method. METHODS: This study has been conducted on 3 clinical cases: case 1, non-Hodgkin lymphoma treated with (131)I-tositumomab; case 2, a neuroendocrine tumor treatment simulated with (177)Lu-peptides; and case 3, hepatocellular carcinoma treated with (90)Y-microspheres. Absorbed dose calculations were performed using a direct Monte Carlo approach accounting for TDH (3D-RD), and a DK approach (VoxelDose, or VD). For each individual voxel, the VD absorbed dose, D(VD), calculated assuming uniform density, was corrected for density, giving D(VDd). The average 3D-RD absorbed dose values, D(3DRD), were compared with D(VD) and D(VDd), using the relative difference Δ(VD/3DRD). At the voxel level, density-binned Δ(VD/3DRD) and Δ(VDd/3DRD) were plotted against ρ and fitted with a linear regression. RESULTS: The D(VD) calculations showed a good agreement with D(3DRD). Δ(VD/3DRD) was less than 3.5%, except for the tumor of case 1 (5.9%) and the renal cortex of case 2 (5.6%). At the voxel level, the Δ(VD/3DRD) range was 0%-14% for cases 1 and 2, and -3% to 7% for case 3. All 3 cases showed a linear relationship between voxel bin-averaged Δ(VD/3DRD) and density, ρ: case 1 (Δ = -0.56ρ + 0.62, R(2) = 0.93), case 2 (Δ = -0.91ρ + 0.96, R(2) = 0.99), and case 3 (Δ = -0.69ρ + 0.72, R(2) = 0.91). The density correction improved the agreement of the DK method with the Monte Carlo approach (Δ(VDd/3DRD) < 1.1%), but with a lesser extent for the tumor of case 1 (3.1%). At the voxel level, the Δ(VDd/3DRD) range decreased for the 3 clinical cases (case 1, -1% to 4%; case 2, -0.5% to 1.5%, and -1.5% to 2%). No more linear regression existed for cases 2 and 3, contrary to case 1 (Δ = 0.41ρ - 0.38, R(2) = 0.88) although the slope in case 1 was less pronounced. CONCLUSION: This study shows a small influence of TDH in the abdominal region for 3 representative clinical cases. A simple density-correction method was proposed and improved the comparison in the absorbed dose calculations when using our voxel S value implementation

    The Role of Ceramide Synthases in the Pathogenicity of Cryptococcus neoformans.

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    Cryptococcus neoformans (C. neoformans) is estimated to cause about 220,000 new cases every year in patients with AIDS, despite advances in antifungal treatments. C. neoformans possesses a remarkable ability to disseminate through an immunocompromised host, making treatment difficult. Here, we examine the mechanism of survival of C. neoformans under varying host conditions and find a role for ceramide synthase in C. neoformans virulence. This study also provides a detailed lipidomics resource for the fungal lipid research community in addition to discovering a potential target for antifungal therapy. Cell Rep 2018 Feb 6; 22(6):1392-140
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