1,721,050 research outputs found
Secondary aneurysmal bone cyst in fibrous dysplasia of the proximal femur.
No full textFibrous dysplasia of bone is a congenital skeletal disorder characterized by proliferation of spindle cells inside an intramedullary collagenous stroma and by formation of metaplastic bone. An aneurysmal bone cyst is a lesion of unknown etiology. Macroscopically it appears like a blood-filled cavity that expands the affected bone. Histologically, fibrous septa are bordered by macrophages, giant cells, inflammatory cells, and areas of bone production. Hemorrhagic areas can rise into fibrous dysplasia. The lesion appears as an aggressive and destructive process that is difficult to diagnose properly. A 29-year-old woman presented with a 2-year history of left inguinal and lumbar pain. She reported increased pain after physical activity. Magnetic resonance imaging of the left femur (without intravenous gadolinium) showed a mass extending 14 cm along the femoral metaphysis. This lesion involved cortical bone that was broken in the posteromedial site. Computed tomography confirmed the osteostructural lytic alteration that "blows up" the proximal femur metaphysis. A trochar biopsy allowed the diagnosis of aneurysmal bone cyst on fibrous dysplasia, excluding malignancy. The lesion was treated with curettage and local adjuvants and filled with bone grafts. Internal fixation with a sliding screw plate was also performed. Radiographs at 1 year postoperatively showed good consolidation of the grafts and absence of local recurrence. The patient achieved active and passive mobilization of the left hip with no pain. Copyright © 2009 SLACK Incorporated. All rights reserved
Nano-metering of Solvated Biomolecules Or Nanoparticles from Water Self-Diffusivity in Bio-inspired Nanopores
Full text linkTaking inspiration from the structure of diatom algae frustules and motivated by the need for new detecting strategies for emerging nanopollutants in water, we analyze the potential of nanoporous silica tablets as metering devices for the concentration of biomolecules or nanoparticles in water. The concept relies on the different diffusion behavior that water molecules exhibit in bulk and nanoconfined conditions, e.g., in nanopores. In this latter situation, the self-diffusion coefficient of water reduces according to the geometry and surface properties of the pore and to the concentration of suspended biomolecules or nanoparticles in the pore, as extensively demonstrated in a previous study. Thus, for a given pore-liquid system, the self-diffusivity of water in nanopores filled with biomolecules or nanoparticles provides an indirect measure of their concentration. Using molecular dynamics and previous results from the literature, we demonstrate the correlation between the self-diffusion coefficient of water in silica nanopores and the concentration of proteins or nanoparticles contained therein. Finally, we estimate the time required for the nanoparticles to fill the nanopores, in order to assess the practical feasibility of the overall nano-metering protocol. Results show that the proposed approach may represent an alternative method for assessing the concentration of some classes of nanopollutants or biomolecules in water
Histogenetic characterization of giant cell tumor of bone
No full textThe unpredictable behavior of giant cell tumor (GCT) parallels its controversial histogenesis. Multinucleated giant cells, stromal cells, and CD68(+) monocytes/macrophages are the three elements that interact in GCT. We compared the ability of stromal cells and normal mesenchymal stromal cells to differentiate into osteoblasts. Stromal cells and mesenchymal cells had similar proliferation rates and lifespans. Although stromal cells expressed early osteogenic markers, they were unable to differentiate into osteoblasts but they did express intracellular adhesion molecule-1, a marker of bone-lining cells. They were unable to form clones in a semisolid medium and unable to promote osteoclast differentiation, although they exerted a strong chemotactic effect on osteoclast precursors. Stromal cells may be either immature proliferating osteogenic elements or specialized osteoblast-like cells that fail to show neoplastic features but can induce the differentiation of osteoclast precursors. They might be secondarily induced to proliferate by a paracrine effect induced by monocyte-macrophages and/or giant cells. The increased number of giant cells in GCT may be secondary to an autocrine circuit mediated by the receptor activator of nuclear factor kB
Characterisation and modelling of water wicking and evaporation in capillary porous media for passive and energy-efficient applications
Full text linkPassive devices based on water wicking and evaporation offer a robust, cheap, off-grid, energy-efficient and sustainable alternative to a wide variety of applications, ranging from personal thermal management to water treatment, from filtration to sustainable cooling technologies. Among the available, highly-engineered materials currently employed for these purposes, polyethylene-based fabrics offer a promising alternative thanks to the precise control of their fabrication parameters, their light-weight, thermal and mechanical properties, chemical stability and sustainability. As such, both woven and non-woven fabrics are commonly used in capillary-fed devices, and their wicking properties have been extensively modelled relying on analytical equations. However, a comprehensive and flexible modelling framework able to investigate and couple all the heat and mass transfer phenomena regulating the water dynamics in complex 2-D and 3-D porous components is currently missing. This work presents a comprehensive theoretical model aimed to investigate the wetting and drying performance of hydrophilic porous materials depending on their structural properties and on the external environmental conditions. The model is first validated against experiments (R2=0.99 for the wicking model; errors lower than 14% and 1% for the evaporation and radiative models, respectively), then employed in three application cases: the characterisation of the capillary properties of a novel textile; the assessment of the thermal performance of a known material for personal thermal management when used in different conditions; the model-assisted design of a porous hydrophilic component of passive devices for water desalination. The obtained results showed a deep interconnection between the different heat and mass transfer mechanisms, the porous structure and external working conditions. Thus, modelling their non-linear behaviour plays a crucial role in determining the optimal material characteristics to maximise the performance of porous materials for passive devices for the energy and water sector
Gorham-Stout disease: the experience of the Rizzoli Institute and review of the literature.
No full textGorham-Stout disease (also known as "disappearing bone disease") was first described by Jackson in 1838, but was properly defined by Gorham and Stout in a series of 24 patients in 1954-1955. It is a rare disease of unknown etiology (about 200 cases reported in the literature) characterized by spontaneous progressive resorption of bone without malignant proliferation of vascular structures. The diagnosis is one of exclusion and it is based on combined histological, radiological, and clinical features. Benign vascular proliferation with fatty bone marrow and thinning of bony trabeculae is a typical histological feature. Standard radiographs of disappearing bone disease show progressive bony resorption with adjacent soft tissue involvement. Most cases of Gorham-Stout disease resolve spontaneously, but prognosis remains unpredictable. This study reports 13 cases of Gorham-Stout disease treated in our institution from 1968 to 2008. The aim of the work was to review our series and the literature on this rare disease, as well as to evaluate whether or not an optimal treatment can be identified and recommended
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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