3,559 research outputs found
Effect of cytostatic drug presence on extracellular polymeric substances formation in municipal wastewater treated by membrane bioreactor
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
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
Morphology, structure and color properties of mixes films containing a diacetylene and a hemicyanine derivative
Soil and Site Improvements of the Marsh Soils in Puerto De Santa María Highway (Cádiz, Spain)
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
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
Morfología, estructura y propiedades cromáticas de películas mixtas conteniendo polidiacetilenos y colorantes anfifílicos
Web promotion, innovation and postgraduate e-learning programs.
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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