179 research outputs found

    Automatic system for the determination of boron in ceramic frits

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    An automatic system for the potentiometric determination of boron in ceramic frits was developed. The system includes a personal computer for instrumental control, data acquisition and processing, which allows up to 13 samples to be analysed sequentially with no human intervention

    La evaluación de la calidad de la educación como política pública. El caso de la CABA : Algunos elementos para la discusión acerca del sentido de sus transformaciones

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    Development and kinematic verification of a finite element model for the lumbar spine: Application to disc degeneration

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    The knowledge of the lumbar spine biomechanics is essential for clinical applications. Due to the difficulties to experiment on living people and the irregular results published, simulation based on finite elements (FE) has been developed, making it possible to adequately reproduce the biomechanics of the lumbar spine. A 3D FE model of the complete lumbar spine (vertebrae, discs, and ligaments) has been developed. To verify the model, radiological images (X-rays) were taken over a group of 25 healthy, male individuals with average age of 27.4 and average weight of 78.6 kg with the corresponding informed consent. A maximum angle of 34.40° is achieved in flexion and of 35.58° in extension with a flexion-extension angle of 69.98°. The radiological measurements were 33.94 ± 4.91°, 38.73 ± 4.29°, and 72.67°, respectively. In lateral bending, the maximum angles were 19.33° and 23.40 ± 2.39, respectively. In rotation a maximum angle of 9.96° was obtained. The model incorporates a precise geometrical characterization of several elements (vertebrae, discs, and ligaments), respecting anatomical features and being capable of reproducing a wide range of physiological movements. Application to disc degeneration (L5-S1) allows predicting the affection in the mobility of the different lumbar segments, by means of parametric studies for different ranges of degeneration

    A predictive mechanical model for evaluating vertebral fracture probability in lumbar spine under different osteoporotic drug therapies

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    Osteoporotic vertebral fractures represent a major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture from bone mineral density (BMD) measurements.A previously developed model, based on the Damage and Fracture Mechanics, was applied for the evaluation of the mechanical magnitudes involved in the fracture process from clinical BMD measurements. BMD evolution in untreated patients and in patients with seven different treatments was analyzed from clinical studies in order to compare the variation in the risk of fracture. The predictive model was applied in a finite element simulation of the whole lumbar spine, obtaining detailed maps of damage and fracture probability, identifying high-risk local zones at vertebral body.For every vertebra, strontium ranelate exhibits the highest decrease, whereas minimum decrease is achieved with oral ibandronate. All the treatments manifest similar trends for every vertebra. Conversely, for the natural BMD evolution, as bone stiffness decreases, the mechanical damage and fracture probability show a significant increase (as it occurs in the natural history of BMD). Vertebral walls and external areas of vertebral end plates are the zones at greatest risk, in coincidence with the typical locations of osteoporotic fractures, characterized by a vertebral crushing due to the collapse of vertebral walls.This methodology could be applied for an individual patient, in order to obtain the trends corresponding to different treatments, in identifying at-risk individuals in early stages of osteoporosis and might be helpful for treatment decisions

    La evaluación de la calidad de la educación como política pública : El caso de la CABA: algunos elementos para la discusión acerca del sentido de sus transformaciones

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    En Estados Unidos y los países centrales, la evaluación de la educación tomó un fuerte impulso como consecuencia de la crisis de los ´70, integrada a la implantación de políticas de Nueva Derecha (Morgenstern, 1990), y centrada en la transformación del Estado y la contención del gasto público. En esos países, esta etapa estuvo precedida por la conformación de un compacto cuerpo teórico-metodológico alrededor de la evaluación del logro de los sistemas educativos (SEs), desarrollado por organizaciones académicas y tecnopolíticas que, tempranamente, forjaron redes de cooperación e intercambio con organismos internacionales. Así concebida, la evaluación se ligó estrechamente al concepto –ambiguo y polisémico- de “la mejora de la calidad de la educación”. (Párrafo extraído del texto a modo de resumen)Mesa 37: Sociología política de la educación. Políticas educativas, Gestión institucional y el escenario de la educación como derechoFacultad de Humanidades y Ciencias de la Educació

    Occupational exposures and distribution of natural radionuclides in phosphoric acid production by the wet process (Spain)

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    The industries devoted to the production of phosphoric acid use as a raw material large amount of phosphate rock (PR), which– depending on its geological origin –could be enriched in natural radionuclides either from the uranium or thorium series. In addition, and depending of the process used, different by-products also enriched in natural radionuclides are formed. For this reason, these types of industries are considered as one of the most representative examples where NORM and TENORM is handled, and consequently where a detailed radiological study for protection of the workers is needed.In Spain, a quite large industrial complex is located in an estuary in the surroundings of Huelva town (SW of Spain, see Figure 1), with two big factories devoted to the production of phosphoric acid through the so-called “wet-acid process” (see details in Section 2). In these factories, two types of phosphatic ores are processed: a) sedimentary marine origin phosphate ore from Morocco, and b) igneous origin phosphate ore from Kola (Russia). The Moroccan phosphorites are characterised for their high uranium concentrations, ranging 100-150 ppm, while the igneous phosphate rocks from Kola have clearly lower levels of this element. In opposition, the Kola phosphate rocks present concentrations of the 232Th-series in a factor up to 3 to 5 higher than in word average soils, while the Moroccan phosphorites contain clearly lower concentrations from this natural series [1]In both raw materials, both the 238Uand the 232Th are in secular equilibrium with their daughters. Nevertheless, during the application of the industrial process, the aforementioned secular equilibrium is broken, suffering the different radionuclides their redistributions between intermediate products according to their respective chemical characteristics [2]. This fact need to be taken into consideration for a proper radiological study inside the factories

    La evaluación de la calidad de la educación como política pública : El caso de la CABA: algunos elementos para la discusión acerca del sentido de sus transformaciones

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    En Estados Unidos y los países centrales, la evaluación de la educación tomó un fuerte impulso como consecuencia de la crisis de los ´70, integrada a la implantación de políticas de Nueva Derecha (Morgenstern, 1990), y centrada en la transformación del Estado y la contención del gasto público. En esos países, esta etapa estuvo precedida por la conformación de un compacto cuerpo teórico-metodológico alrededor de la evaluación del logro de los sistemas educativos (SEs), desarrollado por organizaciones académicas y tecnopolíticas que, tempranamente, forjaron redes de cooperación e intercambio con organismos internacionales. Así concebida, la evaluación se ligó estrechamente al concepto –ambiguo y polisémico- de “la mejora de la calidad de la educación”. (Párrafo extraído del texto a modo de resumen)Mesa 37: Sociología política de la educación. Políticas educativas, Gestión institucional y el escenario de la educación como derechoFacultad de Humanidades y Ciencias de la Educació

    Stimulation of TLR3 Triggers Release of Lysosomal ATP in Astrocytes and Epithelial Cells That Requires TRPML1 Channels

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    Cross-reactions between innate immunity, lysosomal function, and purinergic pathways may link signaling systems in cellular pathologies. We found activation of toll-like receptor 3 (TLR3) triggers lysosomal ATP release from both astrocytes and retinal pigmented epithelial (RPE) cells. ATP efflux was accompanied by lysosomal acid phosphatase and beta hexosaminidase release. Poly(I:C) alkalinized lysosomes, and lysosomal alkalization with bafilomycin or chloroquine triggered ATP release. Lysosomal rupture with glycyl-L-phenylalanine-2-naphthylamide (GPN) eliminated both ATP and acid phosphatase release. Secretory lysosome marker LAMP3 colocalized with VNUT, while MANT-ATP colocalized with LysoTracker. Unmodified membrane-impermeant 21-nt and non-targeting scrambled 21-nt siRNA triggered ATP and acid phosphatase release, while smaller 16-nt RNA was ineffective. Poly(I:C)-dependent ATP release was reduced by TBK-1 block and in TRPML1-/- cells, while TRPML activation with ML-SA1 was sufficient to release both ATP and acid phosphatase. The ability of poly(I:C) to raise cytoplasmic Ca2+ was abolished by removing extracellular ATP with apyrase, suggesting ATP release by poly(I:C) increased cellular signaling. Starvation but not rapamycin prevented lysosomal ATP release. In summary, stimulation of TLR3 triggers lysosomal alkalization and release of lysosomal ATP through activation of TRPML1; this links innate immunity to purinergic signaling via lysosomal physiology, and suggests even scrambled siRNA can influence these pathways. © 2018 The Author(s)

    Phage inducible islands in the gram-positive cocci

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    The SaPIs are a cohesive subfamily of extremely common phage-inducible chromosomal islands (PICIs) that reside quiescently at specific att sites in the staphylococcal chromosome and are induced by helper phages to excise and replicate. They are usually packaged in small capsids composed of phage virion proteins, giving rise to very high transfer frequencies, which they enhance by interfering with helper phage reproduction. As the SaPIs represent a highly successful biological strategy, with many natural Staphylococcus aureus strains containing two or more, we assumed that similar elements would be widespread in the Gram-positive cocci. On the basis of resemblance to the paradigmatic SaPI genome, we have readily identified large cohesive families of similar elements in the lactococci and pneumococci/streptococci plus a few such elements in Enterococcus faecalis. Based on extensive ortholog analyses, we found that the PICI elements in the four different genera all represent distinct but parallel lineages, suggesting that they represent convergent evolution towards a highly successful lifestyle. We have characterized in depth the enterococcal element, EfCIV583, and have shown that it very closely resembles the SaPIs in functionality as well as in genome organization, setting the stage for expansion of the study of elements of this type. In summary, our findings greatly broaden the PICI family to include elements from at least three genera of cocci

    Estudio de la resistencia a compresión de morteros fabricados con conglomerante compuesto de polvo de vidrio

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    This research evaluates the resistance of mortars made with mixtures of different compositions, where a part of the traditional binder is replaced by glass power in a simple way to analyze the mechanical properties of the reactive samples obtained in this way. The tests were carried out with mortars. To facilitate the reactions are added to the mixtures being analyzed different reagents, mixing the glass powder with basic reagents, allowing the collection of conditions of pH greater than 12, ins which the soda-lime glass is very reactive. Analyzed the different specimens of mortar, shows, that the glass powder and its fineness, play an important role in the increasing the compressive strength of the mixtures.Esta investigación evalúa la resistencia de morteros realizados con mezclas de diferentes composiciones, donde una parte del conglomerante tradicional es sustituido por el polvo de vidrio para analizar de una forma sencilla las características mecánicas de las muestras reactivas obtenidas de esta forma. Los ensayos se han realizado con morteros. Para facilitar las reacciones se añaden a las mezclas objeto del análisis diferentes reactivos: se mezcla el polvo de vidrio con reactivos básicos, lo que permite la obtención de condiciones de pH superiores a 12, en las que el vidrio sodo-cálcico es muy reactivo. Analizadas las diferentes probetas de morteros, se observa que el polvo de vidrio, así como su granulometría, juegan un importante papel en el aumento de las resistencias mecánicas a compresión de las mezclas
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