3,559 research outputs found

    Effect of cytostatic drug presence on extracellular polymeric substances formation in municipal wastewater treated by membrane bioreactor

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    The effect of the cyclophosphamide and its mean metabolites on extracellular polymeric substances (EPS) formation was investigated. Two lab-scale membrane bioreactors were followed in parallel (one with the cytostatic drugs, the second without). Chromatographic and spectroscopic studies (UV–Vis spectroscopy and IR spectroscopy) showed that the presence of CPs induced an increase in EPS concentration in the biological sludge, especially of soluble substances, mainly polysaccharides and proteins. Size exclusion chromatography analysis revealed that in the presence of CPs, macromolecular EPS were formed (polysaccharides corresponding to about 6 KDa and proteins to about 18 KDa). The formation of EPS seemed to be a protection mechanism. More important membrane fouling in reactor with CPs seemed to be related to the retention of an increased amount of soluble substances

    Comportamiento catalítico de una Bentonita modificada con Manganeso en la oxidación en fase húmeda de naranja de metilo con peróxido de hidrógeno

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    En este trabajo se presenta un estudio comparativo en el que se introduce manganeso en una bentonita colombiana proveniente del Valle del Cauca (BVC) utilizando tres métodos: i) pilarización con Al 2 O 3 y posterior impregnación húmeda con una disolución acuosa de manganeso, ii) co-intercalación con una disolución oligomérica mixta de Al-Mn seguida de una etapa de calcinación y iii) homoionización con Mn 2+ y posterior formación in-situ de agregados tipo MnS. Los sólidos resultantes son caracterizados por espectroscopía de absorción atómica (EAA), capacidad de intercambio catiónico (CIC) y difracción de rayos X en polvo (DRX), y evaluados como catalizadores en la oxidación de naranja de metilo con peróxido de hidrógeno

    Soil and Site Improvements of the Marsh Soils in Puerto De Santa María Highway (Cádiz, Spain)

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    The Puerto de Santa Maria and Puerto Real news highways are 17.4 kms. long, of which about 9 kms. run through a marshland area. The soft soil surveys involved piezocone reconnaissances and the construction of 3 experimental embankments. The embankments rest on ground improved with vertical drains for heights between 2.5 and 4.0 m., and with gravel columns for heights between 4.0 and 9.0 m. Expanded polystyrene was also used, for the first time in Spain, as a light fill in the embankments providing access to one of the bridges. The foundations for the 9 bridges located in the marshland were large diameter, precast, driven pier-piles (Raymond type). Embankment settlement was monitored and controlled by continuous settlement measuring lines. Pile driving was also PDA controlled

    Double acid etching treatment of dental implants for enhanced biological properties

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    Background: The topographical features on the surface of dental implants have been considered as a critical parameter for enhancing the osseointegration of implants. In this work, we proposed a surface obtained by a combination of shot blasting and double acid etching. The double acid etching was hypothesized to increase the submicron topography and hence further stimulate the biological properties of the titanium implant. Methods: The topographical features (surface roughness and real surface area), wettability and surface chemical composition were analyzed. Results: The results showed that the proposed method produced a dual roughness, mainly composed of randomly distributed peaks and valleys with a superimposed nanoroughness, and hence with an increased specific surface area. Despite the fact that the proposed method does not introduce significant chemical changes, this treatment combination slightly increased the amount of titanium available on the surface, reducing potential surface contaminants. Furthermore, the surface showed increased contact angle values demonstrating an enhanced hydrophobicity on the surface. The biological behavior of the implants was then assessed by culturing osteoblast-like cells on the surface, showing enhanced osteoblast adhesion, proliferation and differentiation on the novel surface. Conclusions: Based on these results, the described surface with dual roughness obtained by double acid etching may be a novel route to obtain key features on the surface to enhance the osseointegration of the implant. Our approach is a simple method to obtain a dual roughness that mimics the bone structure modified by osteoclasts and increases surface area, which enhances osseointegration of dental implants.Peer ReviewedPostprint (author's final draft

    Web promotion, innovation and postgraduate e-learning programs.

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    This study analyzes the diffusion that the main Spanish universities carry out in their corporate web pages in relation to the e-learning programs, both semi-online and online. The objective is to know if this diffusion takes into account the communication of methodological aspects and trends that could be differentiators of an innovative offer.To this end, the most prestigious Spanish universities (public and private) have been selected, as well as those relevant in the field of e-learning. Subsequently, using the methodology "Counting methods" (Law, Qi and Buhalis, 2010), (translated into Spanish as method of itemization), the websites of each of the 689 programs offered have been analyzed. The research allows identifying the common variables used in the web promotion of all universities, and contrasts the presence of the main trends in e-learning as differentiating elements of a competitive offer.
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