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Interfacial electron transfer between Geobacter sulfurreducens and gold electrodes via carboxylate-alkanethiol linkers: Effects of the linker length
No full textGeobacter sulfurreducens (Gs) attachment and biofilm formation on self-assembled monolayers (SAMs) of carboxyl-terminated alkanethiol linkers with varied chain length on gold (Au) was investigated by electrochemical and microscopic methods to elucidate the effect of the surface modification on the current production efficiency of Gs cells and biofilms. At the initial stage of the cell attachment, the electrochemical activity of Gs cells at a submonolayer coverage on the SAM-Au surface was independent of the linker length. Subsequently, multiple potential cyclings indicated that longer linkers provided more biocompatible conditions for Gs cells than shorter ones. For Gs biofilms, on the other hand, the turnover current decreased exponentially with the linker length. During the biofilm formation, bacteria need to adjust from the initial planktonic state to an electrode-respiring state, which was triggered by a strong electrochemical stress found for shorter linkers, resulting in the formation of mature biofilms. Our results suggest that the initial cell attachment and the biofilm formation are two inherently different processes. Therefore, the effects of linker molecules, electron transfer efficiency and biocompatibility, must be explored simultaneously to understand both processes to increase the current production of electrogenic microorganisms in microbial fuel cells
Stability and toxicity studies for duloxetine and econazole on Spirodela polyrhiza using chiral capillary electrophoresis
No full textFunctional nanostructured materials for technological and biomedical applications / Materiales nanoestructurados con efecto biocida para la mejora en la eficiencia del uso de agua en la industria hortofrutícola
No full textcarcinoma epitelioide de cuello uterino, HeLa, y células epiteliales de córnea humana, HCEpC. Se determinó que es posible preparar nanofibras estables en agua a partir PAA/PVA mediante curado térmico a 140 °C gracias a la formación de enlaces anhídrido, cetona y éster. Se pudieron obtener nanofibras estables y con morfología suave utilizando una proporción de PAA mayor del 35% en peso sobre el material seco final, con una tendencia a la absorción de agua que disminuye con el contenido de PAA. Por otro lado, las fibras de PAA/PVA se utilizaron como base de funcionalización para la creación de materiales compuestos. Para ello se anclaron dendrímeros poliamidoamina (PAMAM-NH2) de generaciones 3 y 5 mediante la formación de enlaces amida con los grupos carboxilo de PAA usando un agente de acoplamiento. Se consiguieron anclar hasta 2.3-6.5 µmol de dendrímero por gramo de membrana. Los materiales de PAA/PVA injertados con dendrímeros PAMAM se utilizaron para la encapsulación de productos químicos hidrófobos para lo que se aprovecharon las cavidades internas no polares de los dendrímeros. Se estudió la encapsulación de tolueno, como ejemplo de contaminante acuoso de bajo peso molecular, y timol, compuesto antioxidante de interés para aplicaciones de liberación controlada. Los resultados experimentales se compararon con cálculos computacionales que permitieron determinar el número de moléculas incluidas en las cavidades internas del dendrímero o unidas a su superficie del mediante interacciones secundarias. Los materiales basados en PAA mostraron una actividad antimicrobiana importante, particularmente contra Staphylococcus aureus que se atribuyó a la quelación de los cationes divalentes que estabilizan las envolturas externas de las paredes celulares bacterianas por parte de los grupos carboxilato del PAA. El daño en las membranas bacterianas se evidenció en una la disminución del calcio intracelular y fue mayor para las fibras con mayor contenido de PAA y para las bacterias Gram positivas con respecto a las Gram negativas. Las membranas PAMAM-PVA/PAA mostraron una gran capacidad antibacteriana debido a la carga positiva de los dendrímeros, que interactúan con las membranas biológicas cargadas negativamente. El daño en la membrana celular pudo identificarse como la causa principal del efecto antibacteriano. Los hilos PAMAM-PAA/PVA se mantuvieron esencialmente libres de colonización bacteriana incluso tras el contacto prolongado con cultivos de bacterias en crecimiento exponencial. Las fibras de PAA/PVA se utilizaron también para la inmovilización de los AMPs nisina, lisozima y ¿-poli(L-lisina). El autoensamblaje electrostático fue favorecido por condiciones de pH que maximizan la interacción electrostática entre los hilos de PAA/PVA, con carga negativa, y los péptidos, con carga positiva. Los resultados mostraron péptidos distribuidos homogéneamente en toda la red fibrosa y cuyo efecto antibacteriano fue función de la movilidad del péptido a su vez determinado por el pH del medio externo. Los mejores resultados se obtuvieron para la lisozima, cuando se produjeron fibras libres de crecimiento microbiano incluso después de dos semanas en contacto con sus cultivos. Como conclusión, este estudio demostró la posibilidad de producir nanofibras poliméricas electrohiladas estables en agua a partir de mezclas de PAA/PVA para crear materiales con actividad antibacteriana que pueden usarse también como soportes para la unión de moléculas activas mediante estrategias de post-funcionalización. Los materiales nanofibrosos se mostraron como materiales capaces de interactuar con moléculas no polares presentes en el medio externo, así como para la liberación controlada de sustancias activas. Los resultados mostraron el potencial de las fibras electrohiladas preparadas con materiales ambientalmente benignos para crear membranas, apósitos y soportes nanofibrosos para una variedad de aplicaciones tecnológicas y biomédicas
Superhydrophobic nanofibers electrospun by surface segregating fluorinated amphiphilic additive for membrane distillation
No full textDevelopment of lox-cost equipment based on open source tools
No full textLa rápida evolución de las energías renovables y de la tecnología solar fotovoltaica durante los últimos años ha llevado a la proliferación de numerosas instalaciones fotovoltaicas en todo el mundo. En el caso de los sistemas fotovoltaicos autónomos, las instalaciones son de tamaño y coste reducido encontrándose en la mayoría de las ocasiones en localizaciones remotas de países en desarrollo. Por desgracia, una vez realizada la instalación de estos sistemas es muy difícil hacer un seguimiento del buen funcionamiento de los mismos confiando en los componentes utilizados y en el correcto uso que realicen de la misma los usuarios finales. El objetivo de esta tesis es realizar el diseño y desarrollo de un sistema de monitorización de bajo coste, que sea adecuado para la monitorización de estos sistemas fotovoltaicos autónomos instalados en áreas rurales de países en desarrollo contribuyendo al éxito de los programas de electrificación rural.
In recent years, the rapid evolution of the solar energy as well as the photovoltaic technologies has led to the proliferation of a vast number of photovoltaic installations worldwide. Millions of stand-alone photovoltaic systems are installed in rural areas of developing countries. One of the main problems in rural electrification programmes is the lack of monitoring. Small stand-alone photovoltaic systems are limited by size and cost and it is very difficult to monitor their proper functioning. The objective of this thesis is to design and develop a low-cost monitoring system, suitable for the monitoring of small stand- alone photovoltaic systems installed in rural areas of developing countries contributing to the success of rural electrification programs
IoT application for real-time monitoring of Solar Home Systems based on ArduinoTM with 3G connectivity
No full textA novel datalogger based on free software and hardware has been designed, built, programmed and installed as an experimental prototype in multiple sites. Remote monitoring extends the effectiveness of the datalogger in areas deprived of electrical grid and traditional wired telecommunication networks. The integration of Internet of Things (IoT) in solar measurement systems allows the remote monitoring of small stand-alone photovoltaic (PV) systems, enhancing the performance and the maintenance of the system. The datalogger measured electric and climatic parameters (up to 14 parameters, expandable) with the required accuracy established by the IEC61724 standard; to include 3G technology in it allowed the stand-alone PV systems system monitoring remotely via web or via mobile application, all at low cost. An outdoor campaign of over 12 months under the harsh environmental conditions at multiple locations was performed to test the new datalogger under real and different conditions demonstrating the robustness and the reliability of the system
Using old cartography for the inventory of a forgotten heritage: The hydraulic heritage of the Community of Madrid
No full textHydraulic heritage is a legacy that has generally been forgotten in territorial management and protective actions. This heritage expresses the way in which inhabitants have used their water resources and related structures for centuries. For proper management, it is necessary to draw up an inventory. Using Geographical Information System (GIS) tools, we have created a spatial and thematic inventory of the hydraulic heritage located in the Community of Madrid. This inventory shows the good conditions, both in abundance (more than 5800 point type entities) and diversity (28 categories in the point entities type layer), of historical hydraulic elements in the region. All the information in this work has been extracted from old maps (1870–1960). A database was designed to provide spatial, thematic and temporal information on this heritage. Element distribution was concentrated mainly in the river plains and the metropolitan areas of the region, and it has been proven how hydraulic elements are endangered due to increasing urban pressure. This phenomenon and agricultural modernisation are the main factors influencing the survival of this type of assets. Thanks to this methodology, it should be possible to analyse the status of the heritage ensemble included in the inventory
Identification of contaminants of concern in the upper Tagus river basin (central Spain). Part 1: Screening, quantitative analysis and comparison of sampling methods
No full textPesticides and point source contaminants (primarily pharmaceuticals) were monitored in 16 sampling sites of the upper Tagus river basin during spring, summer and autumn of 2016. A qualitative screening analysis was performed using a library of 430 compounds. Next, a novel method was implemented for the selection and quantification of contaminants with LC-MS/MS. The method is based on the frequency of detection in the screening, ecotoxicity data and the potential use in the watershed. Moreover, the efficacy of grab samples and passive samples (POCIS) in detecting compound-specific exposure patterns was compared during the summer sampling campaign. The screening method detected the presence of 268 compounds in the study area, out of which 52 were selected for the quantitative analysis (20 pesticides and 32 point source chemicals). Although very helpful in the prioritization exercise, the qualitative screening demonstrated some biases and the need for improvement by using more effective instruments for confirming positive results. Grab samples proved not to be fully suitable for contaminants with discontinuous exposure such as pesticides, which may be underestimated, but offer a sufficient basis for the characterization of contaminants coming from urban wastewaters. All selected chemicals showed a very high concentration variability due to differences among sampling sites, which are related to agricultural intensity and demographic pressure. Some insecticides (chlorpyrifos, dimethoate, imidacloprid), herbicides (diuron, metribuzine, simazine, terbuthylazine), and fungicides (carbendazim) were measured at concentrations exceeding 100 ng/L; while paracetamol, ibuprofen, some antibiotics (azithromycin, sulfamethoxazole, trimethoprim) and life-style compounds (caffeine, paraxanthine, nicotine) were found at very high concentrations (up to several μg/L). The results of this work represent the basis for the development of an ecological risk assessment for the aquatic ecosystem in the upper Tagus river basin and for the identification of basin-specific contaminant mixtures of environmental concern
SCIENTIFIC ADVICE ON Safety, health and environmental risks associated with the use of four candidates for a common fiscal marker (Submission II)
No full textUpon a request by DG TAXUD, on 19 March 2018 SCHEER adopted a scientific advice on safety, health and environmental risks associated with the use of four candidates for a common fiscal marker, taking into account the marking level specified by the applicants and its combustion products. The general conclusions were that the information provided by the Applicants for the four chemicals was not sufficient/robust enough to carry out the environmental and human health risk assessments. Analogously, limited information or no information at all was provided that would have made it possible to conclude on the safety of combustion products derived from the markers.
Following the adoption of 1st Advice by the SCHEER, the Applicants provided further information, in order to possibly fill the identified data gaps. The new information provided allowed the SCHEER to conclude that:
1. ACCUTRACETM PLUS does not represent a risk for both either the environment and human health in the condition of use. Concerning the combustion of the candidate fuel marker when mixed in gas oil, biodiesel and kerosene with the recommended marking level, it was considered that would not lead to health and environmental risks.
2. For ACCUTRACETM LOCK, although risks for human health can be excluded, the safety for the environment could not be properly assessed. Regarding the combustion of the candidate fuel marker when mixed in gas oil, biodiesel and kerosene with the recommended marking level, it was considered that would not lead to health and environmental risks.
3. The risks associated to the use of AUTHENTIX MSX 208 and its combustion products when mixed in gas oil, biodiesel and kerosene with the recommended marking level cannot be assessed mainly related to the absence of exposure data for both human health and environment.
4. The risks associated to the use of Carburex NX27 and its combustion products when mixed in gas oil, biodiesel and kerosene with the recommended marking level cannot be assessed due to data gaps in the hazard assessment and lack of exposure data for both human health and environment
