Control presináptico por receptores acoplados a proteínas G, GPCRs, en un ratón modelo del síndrome del X frágil

El síndrome del X frágil (FXS) es la enfermedad mental de carácter hereditario más importante y se asocia con alteraciones como déficits cognitivos, hiperactividad, ansiedad y problemas de interacción social. En el FXS se produce un silenciamiento del gen Fmr1 que codifica para la proteína FMRP, que regula la expresión génica mediante su interacción con ARNm. Cuando FMRP está ausente, se produce una alteración en la expresión de gran cantidad de proteínas postsinápticas así como en formas de plasticidad a largo plazo. Además, FMRP se localiza en axones y en el terminal presináptico donde también regula la expresión de múltiples proteínas presinápticas..

Kinetics of tetrabromobisphenol A pyrolysis. Comparison between correlation and mechanistic models

Brominated flame retardants are well recognized as being highly effective flame retardants. 4-4′-Isopropylidenebis(2,6-dibromophenol), commonly known as tetrabromobisphenol A, is the brominated flame retardant with the largest production volume and is used to improve fire safety, mainly of laminates in electrical and electronic equipment. A kinetic study of the pyrolysis of TBBA has been carried out to obtain decomposition parameters under different operating conditions and taking into account that TBBA is a compound with a high boiling point and that vaporization occurs simultaneously to decomposition. Dynamic runs and dynamic + isothermal run at different heating rates and using different masses of sample were correlated simultaneously. All TG runs were fitted with a unique set of kinetic parameters that is able to explain all the experiments. Moreover, a simplified detailed kinetic model has been developed and the kinetic parameters obtained satisfactorily reproduce the thermal decomposition of TBBA.Support for this work was provided by PROMETEO/2009/043/FEDER and ACOMP2011/224 of Generalitat Valenciana (Spain) and CTQ2008-05520 (Spanish MCI/research)

Analysis of the vaporization process in TG apparatus and its incidence in pyrolysis

An analysis of the evaporation process of n-hexadecane in a thermogravimetric apparatus was carried out. n-Hexadecane represents a typical example of a high boiling point compound and its study is interesting for understanding those processes where vaporization takes place in parallel with pyrolysis during thermal treatment. The process has been studied under different operating conditions: nitrogen and air atmospheres, and isothermal and dynamic runs with three different heating rates from 5 K/min to 20 K/min. The experimental data were satisfactorily correlated to a n-order model with zero process order and the same apparent activation energy for all runs, but the exponential factors of the different runs depended on the initial mass and the heating rate. The experimental results were compared with those predicted considering the diffusion process inside the crucible, taking into account the vapor pressure and the diffusion coefficient of n-hexadecane. A parameter, product of these two variables, can be estimated from a single TG run, so the vaporization process in other equipment and/or operating conditions can also be estimated.Support for this work was provided by PROMETEO/2009/043/FEDER and ACOMP2010/075 of Generalitat Valenciana (Spain) and CTQ2008-05520 (Spanish MCI/research)

Thermogravimetric Study of the Decomposition of Printed Circuit Boards from Mobile Phones

Paper submitted to the 19th International Symposium on Analytical & Applied Pyrolysis, Linz, Austria, 21-25 May 2012.Printed circuit boards (PCB) are particularly problematic to recycle because of the heterogeneous mix of organic material, metals, and glass fibre. More specifically, the presence of Fe and Cu can catalyze the debromination/hydrogenation reaction, accelerating the formation of chlorinated and brominated dioxins and furans.Ministry of Education and Science (Spain): CTQ2008-05520; Valencian Community Government (Spain): PROMETEO/2009/043/FEDER and ACOMP2011/224

Effect of Temperature, Atmosphere and Metals on the Thermal Degradation of Printed Circuit Boards

The permanent expansion of the market of electrical and electronic equipment (EEE) and the shorter innovation cycles, lead to a faster replacement of these appliances, making EEE a fast-growing source of waste (WEEE). As stated in Directive 2012/19/EU1 on waste electrical and electronic equipment, the content of hazardous components in EEE is a major concern during the waste management phase, and recycling of WEEE is not currently undertaken to a sufficient extent, resulting in a loss of valuable resources.Support for this work was provided by: Ministry of Education and Science (Spain) (CTQ2008-05520 project); Valencian Community Government (Spain) (PROMETEO/2009/043/FEDER project)

Emissions from the Pyrolysis and Combustion of Different Wastes

Paper submitted to the 7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013), New Delhi, India, 23-26 October 2013.A comparison between different emission rates of various pollutants obtained from various wastes is presented. The studied wastes were the following: polyethylene, tyres, sewage sludge, polyvinyl chloride, cotton textiles, polyester textiles, meat and bone meals, varnish wastes, olive oil solid waste (pomace), waste lube oils, paper waste, tomato plant, pine needles and cones, mobile phones and automotive shredder residue. The decomposition of these wastes was studied in a horizontal laboratory scale reactor at 850 ºC in an inert and an oxidizing atmosphere, and the analysis of the pollutants evolved comprised several compounds such as light hydrocarbons, PAHs and PCDD/Fs.Ministry of Education and Science (Spain) (CTQ2008-05520 project) and Valencian Community Government (Spain) (PROMETEO/2009/043/FEDER project)

Pirólisis y combustión de residuos electrónicos

Resumen de la comunicación presentada en el I Congreso de Estudiantes de Ingeniería Química de la Universidad de Alicante, 13-14 abril 2010.Los costes de producción cada vez menores y el aumento de la disponibilidad de equipos electrónicos de todo tipo, incluyendo teléfonos móviles, equipos de audio y vídeo y ordenadores personales, así como sus accesorios, unido a los avances en tecnología que hacen que estos productos queden rápidamente obsoletos, supone un problema de creciente importancia. A este respecto, la Directiva 2002/96/CE del Parlamento Europeo y del Consejo de 27 de enero de 2003 sobre residuos de aparatos eléctricos y electrónicos (RAEE) regula la gestión y eliminación de estos residuos por separado, promoviendo su reutilización, reciclado y recuperación.Las ayudas para la realización de este trabajo proceden de los proyectos CTQ2008-05520 de Ministerio de Educación, Prometeo/2009/043 y ACOM2009/135 de la Generalitat Valenciana

Estudio de la descomposición térmica de tetrabromobisfenol A

Resumen de la comunicación presentada en el XIII Congreso Nacional de Ingeniería Química, Madrid, 18-20 noviembre 2010.Los retardantes de llama son sustancias utilizadas en gran variedad de productos de consumo (muebles, plásticos, textiles, equipos electrónicos,…) para mejorar su resistencia al fuego. Los retardantes de llama bromados (BFR) son los agentes ignífugos más efectivos y los más usados en la actualidad. Diferentes estudios demuestran que su descomposición térmica representa una importante fuente de emisión de contaminantes bromados. Se ha estudiado uno de los retardantes de llama más utilizados, especialmente en circuitos electrónicos: tetrabromobisfenol A (TBBA). Se ha analizado su degradación térmica mediante TG-ADT en distintas atmósferas inertes y oxidativas, a distintas velocidades de calefacción, tanto en condiciones dinámicas como dinámicas+isotermas. Se han realizado experimentos de TG-MS para lograr una mayor comprensión del proceso, así como para identificar algunos de los compuestos emitidos. Con objeto de determinar los productos gaseosos y semivolátiles formados se han llevado a cabo experimentos de pirólisis y combustión a diferentes temperaturas en un reactor horizontal de laboratorio. Se ha propuesto un modelo cinético de descomposición que permite simular los procesos de degradación del TBBA con un único conjunto de parámetros cinéticos válidos para todas las condiciones experimentales. Los gases emitidos en el reactor de laboratorio se han recogido en bolsas Tedlar y se han analizado mediante GC-FID y GC-ECD, siendo los mayoritarios metano, etano, etileno, n-butano, benceno, tolueno y xileno. Se han realizado experimentos de recogida del HBr emitido y análisis mediante cromatografía iónica. Los compuestos semivolátiles se han recogido en resinas XAD, con una posterior extracción con disolventes y análisis mediante GC-MS o HRGC-HRMS. Se ha estudiado el proceso de descomposición del TBBA en un rango medio-alto de temperaturas. Se ha observado que los principales productos de su descomposición son HBr, especies bromadas del bisfenol A y bromofenoles.CTQ2008-05520 de Ministerio de Ciencia e Innovación, Prometeo/2009/043 y ACOMP2010/075 de la Generalitat Valenciana

Análisis de los contaminantes generados en la descomposición térmica de un retardante de llama bromado: tetrabromobisfenol A

Comunicación presentada en la III Reunión Nacional sobre Dioxinas, Furanos y Compuestos Orgánicos Persistentes Relacionados, Santander, 30 junio-1 julio 2011.Los retardantes de llama son compuestos que se añaden a un gran número de materiales con el objeto de reducir el riesgo de incendio. La industria electrónica supone el principal consumidor de retardantes de llama bromados, siendo el tetrabromobisfenol A (TBBPA) el retardante de llama empleado en las placas de circuitos impresos y laminados y en las carcasas de plásticos, especialmente de ABS.Generalitat Valenciana: PROMETEO/2009/043/FEDER y ACOMP2010/075; Ministerio de Educación y Ciencia: CTQ2008-05520

Pollutant emissions during pyrolysis and combustion of waste printed circuit boards, before and after metal removal

The constant increase in the production of electronic devices implies the need for an appropriate management of a growing number of waste electrical and electronic equipment. Thermal treatments represent an interesting alternative to recycle this kind of waste, but particular attention has to be paid to the potential emissions of toxic by-products. In this study, the emissions from thermal degradation of printed circuit boards (with and without metals) have been studied using a laboratory scale reactor, under oxidizing and inert atmosphere at 600 and 850 °C. Apart from carbon oxides, HBr was the main decomposition product, followed by high amounts of methane, ethylene, propylene, phenol and benzene. The maximum formation of PAHs was found in pyrolysis at 850 °C, naphthalene being the most abundant. High levels of 2-, 4-, 2,4-, 2,6- and 2,4,6-bromophenols were found, especially at 600 °C. Emissions of PCDD/Fs and dioxin-like PCBs were quite low and much lower than that of PBDD/Fs, due to the higher bromine content of the samples. Combustion at 600 °C was the run with the highest PBDD/F formation: the total content of eleven 2,3,7,8-substituted congeners (tetra- through heptaBDD/Fs) was 7240 and 3250 ng WHO2005-TEQ/kg sample, corresponding to the sample with and without metals, respectively.Support for this work was provided by the CTQ2013-41006 project from the Ministry of Education and Science (Spain) and the PROMETEO/2009/043/FEDER project from the Valencian Community Government (Spain)