366 research outputs found

    Equivalency and Reciprocity of Qualifications for LIS Professionals in a Web 2.0 Environment

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    In the age of Web 2.0 and globalization of information, the challenge of information professionals included the determination of equivalent educational experiences as professionals move more freely in the international information environment. Reciprocity of degrees among recognized LIS education program is one possible solution, but the establishment of an international program of reciprocity has been difficult up to this time. The authors discuss the background of efforts over a 30 year period to develop acceptable guidelines for international equivalency and reciprocity of qualifications for LIS professionals by IFLA and other library interests. The challenges of the latest IFLA effort our detailed and options provided in a 2.0 web environment are explored. The possibility that applying the principles of interactivity of the web in the 21st Century to provide a solution to the equivalency and reciprocity problem are analyzed and specific proposal are presented for discussion. The results of surveys of library education professionals are presented and specific proposal for the future are outlined

    Digital Libraries in Open Education: the Italy case,

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    Open Education strategies, and specifically MOOC (Massive Open Online Courses) and OER (Open Educational Resources), play an important role in supporting policies for educational innovation, lifelong learning, and, more generally, the enlargement of educational opportunities for all. While there is an increasing interest in Open Education, there is little awareness about the role of Digital Library as learning incubators for learning enhancement. The paper presents briefly the state of art of Digital libraries in the light of the most recent initiatives of Open Education in Italy, towards an integrated model of Digital libraries as “knowledge and learning open hubs”

    Effect of layered double hydroxide intercalated with fluoride ions on the physical, biological and release properties of a dental composite resin

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    OBJECTIVES: The aim of this work was the preparation of a new fluoride-releasing dental material characterized by a release of fluoride relatively constant over time without any initial toxic burst effect. This type of delivery is obtained by a matrix controlled elution and elicits the beneficial effect of a low amount of fluoride on human dental pulp stem cells (hDPSCs) towards mature phenotype. METHODS: The modified hydrotalcite intercalated with fluoride ions (LDH-F), used as filler, was prepared via ion exchange procedure and characterized by X-ray diffraction and FT-IR spectroscopy. The LDH-F inorganic particles (0.7, 5, 10, 20wt.%) were mixed with a photo-activated Bis-GMA/TEGDMA (45/55wt/wt) matrix and novel visible-light cured composites were prepared. The dynamic thermo-mechanical properties were determined by dynamic mechanical analyzer. The release of fluoride ions in physiological solution was determined using a ionometer. Total DNA content was measured by a PicoGreen dsDNA quantification kit to assess the proliferation rate of hDPSCs. Alkaline phosphatase activity (ALP) was measured in presence of fluoride resins. RESULTS: Incorporation of even small mass fractions (e.g. 0.7 and 5wt.%) of the fluoride LDH in Bis-GMA/TEGDMA dental resin significantly improved the mechanical properties of the pristine resin, in particular at 37°C. The observed reinforcement increases on increasing the filler concentration. The release of fluoride ions resulted very slow, lasting months. ALP activity gradually increased for 28 days in hDPSCs cell grown, demonstrating that low concentrations of fluoride contributed to the cell differentiation. CONCLUSIONS: The prepared composites containing different amount of hydrotalcite filler showed improved mechanical properties, slow fluoride release and promoted hDPSCs cell proliferation and cell differentiation

    Modelling sorption thermodynamics and mass transport of n-hexane in a propylene-ethylene elastomer

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    Optimization of post polymerization processes of polyolefin elastomers (POE) involving solvents is of considerable industrial interest. To this aim, experimental determination and theoretical interpretation of the thermodynamics and mass transport properties of POE-solvent mixtures is relevant. Sorption behavior of n-hexane vapor in a commercial propylene-ethylene elastomer (V8880 Vistamaxx™ from ExxonMobil, Machelen, Belgium) is addressed here, determining experimentally the sorption isotherms at temperatures ranging from 115 to 140 °C and pressure values of n-hexane vapor up to 1 atm. Sorption isotherms have been interpreted using a Non Random Lattice Fluid (NRLF) Equation of State model retrieving, from data fitting, the value of the binary interaction parameter for the n-hexane/V8880 system. Both the cases of temperature-independent and of temperature-dependent binary interaction parameter have been considered. Sorption kinetics was also investigated at different pressures and has been interpreted using a Fick’s model determining values of the mutual diffusivity as a function of temperature and of n-hexane/V8880 mixture composition. From these values, n-hexane intra-diffusion coefficient has been calculated interpreting its dependence on mixture concentration and temperature by a semi-empiric model based on free volume arguments

    A Case of Ketron-Goodman Disease

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    Pagetoid reticulosis (PR) is a rare form of cutaneous T-cell lymphoma [Mod Pathol 2000;13:502–510]. Two variants of the disease are described: the localized type Woringer-Kolopp disease (WKD) and the disseminated type Ketron-Goodman disease (KGD). KGD may have disseminated lesions, high rate of recurrence and a guarded prognosis [Mod Pathol 2000;13:502–510]. In patients with KGD, therefore, long-term observation is necessary. Disappearance of cutaneous lesions does not mean resolution of the disease [J Am Acad Dermatol 2002;47:183–186]. Herein we report the case of an 84-year-old man with erythematous patches of the trunk and the upper and lower extremities in whom the diagnosis of KGD was made. We describe this case for the rarity of this pathology and for the good response to therapy (IFN)

    Neuropathology and Inflammatory Cell Characterization in 10 Autoptic COVID-19 Brains

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    COVID-19 presents with a wide range of clinical neurological manifestations. It has been recognized that SARS-CoV-2 infection affects both the central and peripheral nervous system, leading to smell and taste disturbances; acute ischemic and hemorrhagic cerebrovascular disease; encephalopathies and seizures; and causes most surviving patients to have long lasting neurological symptoms. Despite this, typical neuropathological features associated with the infection have still not been identified. Studies of post-mortem examinations of the cerebral cortex are obtained with difficulty due to laboratory safety concerns. In addition, they represent cases with different neurological symptoms, age or comorbidities, thus a larger number of brain autoptic data from multiple institutions would be crucial. Histopathological findings described here are aimed to increase the current knowledge on neuropathology of COVID-19 patients. We report post-mortem neuropathological findings of ten COVID-19 patients. A wide range of neuropathological lesions were seen. The cerebral cortex of all patients showed vascular changes, hyperemia of the meninges and perivascular inflammation in the cerebral parenchyma with hypoxic neuronal injury. Perivascular lymphocytic inflammation of predominantly CD8-positive T cells mixed with CD68-positive macrophages, targeting the disrupted vascular wall in the cerebral cortex, cerebellum and pons were seen. Our findings support recent reports highlighting a role of microvascular injury in COVID-19 neurological manifestations

    Long-Term Fluoride Release from Dental Resins Affects STRO-1+ Cell Behavior.

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    Fluoride-releasing restorative dental materials can be beneficial to remineralize dentin and help prevent secondary caries. However, the effects of fluoride release from dental materials on the activity of dental pulp stem cells are not known. Here we investigate whether different fluoride release kinetics from dental resins supplemented with modified hydrotalcite (RK-F10) or fluoride-glass filler (RK-FG10) could influence the behavior of a human dental pulp stem cell subpopulation (STRO-1(+) cells) known for its ability to differentiate toward an odontoblast-like phenotype. The 2 resins, characterized by similar physicochemical properties and fluoride content, exhibited different long-term fluoride release kinetics. Our data demonstrate that long-term exposure of STRO-1(+) cells to a continuous release of a low amount of fluoride by RK-F10 increases their migratory response to transforming growth factor β1 (TGF-β1) and stromal cell-derived factor 1 (SDF-1), both important promoters of pulp stem cell recruitment. Moreover, the expression patterns of dentin sialoprotein (dspp), dentin matrix protein 1 (dmp1), osteocalcin (ocn), and matrix extracellular phosphoglycoprotein (mepe) indicate a complete odontoblast-like cell differentiation only when STRO-1(+) cells were cultured on RK-F10. On the contrary, RK-FG10, characterized by an initial fluoride release burst and reduced lifetime of the delivery, did not elicit any significant effect on both STRO-1(+) cell migration and differentiation. Taken together, our results highlight the importance of taking into account fluoride release kinetics in addition to fluoride concentration when designing new fluoride-restorative materials
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