79 research outputs found
Regulation of surface expression of the T lymphocyte differentiation antigen, CD8
The murine T lymphocyte glycoprotein CDS is a disulphide bonded heterodimer, composed of αβ or α'β chains, which plays a critical role in regulating the antigen responses of class I MHC-restricted T cells. CDS must interact not only with its ligand, class I MHC, on antigen-expressing target cells, but also with other proteins on the surface of the T ceil itself, such as the antigen-specific T cell receptor. In the present study two additional molecules, of 26 kD and 29 kD molecular weight, associated with the CDS complex have been identified and characterised. The 26 kD molecule is a novel polypeptide preferentially associated with the "immature" forms of CDS (α'β and β alone) and is only found within the cell. The data presented suggest that the 26 kD molecular weight protein may be involved in the developmentally regulated transport of CD8. The second molecule, of 29 kD molecular weight, is found on the cell surface of mature and immature T cells. This molecule appears to be another form of the CD8β polypeptide, with the major difference being the presence of variable amounts of sialic acid. The extent of this sialylation correlates not only with the differentiation status of the T cell but also with its state of activation. The changes in levels of sialic acid may have a significant influence on how CD8 interacts with other molecules. This is the first clear indication of a possible role for the CD8β chain, as previous evidence of CD8 function has been correlated exclusively with the CD8α chain
Diseño de un sistema de comunicaciones V2R
Este Trabajo de Final de Carrera (TFC) tiene como objetivo el diseño y la realización de un sistema de comunicaciones V2R (Vehicle to Roadside), mediante tecnología Bluetooth que permita la comunicación entre vehículos e infraestructura viaria. Dicho sistema estará alimentado eléctricamente a través de placas solares que le darán autonomía y reducirán el impacto medioambiental. Estas comunicaciones inalámbricas forman parte de las denominadas redes cooperativas VANET (Vehicular Ad-Hoc Networks), que se caracterizan por facilitar la comunicación entre vehículos y entre vehículos e infraestructura viaria, lo que puede ser de gran utilidad para reducir el número de accidentes de tráfico, además de proporcionar una conducción más agradable y fluida. Las razones de la utilización de dispositivos Bluetooth son sus magníficas características de robustez, bajo coste y bajo consumo. En este TFC se mostrarán los resultados de varios estudios realizados sobre las características de estos dispositivos, como la velocidad de transmisión de ficheros, la cobertura o la configuración de parámetros que permiten la conexión en un entorno de grandes velocidades. Parece claro que el siguiente paso en los servicios para la automoción apunta al vehículo conectado, por lo que un punto de interés del TFC será el estudio de mercado de estos sistemas. Este sector se identifica como uno de los mercados con mayor potencial de crecimiento, ya que aportará muchas ventajas a los conductores, como predicción de los tiempos de viaje, reacción de manera más eficaz ante incidentes imprevistos o reducción de la contaminación de los vehículos. Por su parte, las autoridades viarias podrán mejorar la gestión y el control de la red de carreteras, aumentar su capacidad, maximizar la eficiencia de los sistemas de transporte público o mejorar la seguridad de todos los conductores
Chemically modified field-effect transistors; potentiometric Ag + selectivity of PVC membranes based on macrocyclic thioethers
Study of a novel bisnaphthalimidopropyl polyamine as electroactive material for perchlorate-selective potentiometric sensors.
In this work, the new polyamine bisnaphthalimidopropyl-4,4'-diaminodiphenylmethane is proposed as a new ionophore for perchlorate potentiometric sensors. The optimal formulation for the membrane comprised of 12mmolkg-1 of the ionophore, and 68% (w/w) of 2-nitrophenyl phenyl ether as plasticizer and 31% (w/w) of high molecular weight PVC. The sensors were soaked in water for a week to allow leakage of anionic impurities and for one day in a perchlorate solution (10-4molL-1) to improve reproducibility due to its first usage. The stability constant for the ionophore-perchlorate association in the membrane, log βIL1=3.18±0.04, ensured a performance characterized by the slope of 54.1 (±0.7) mVdec-1 to perchlorate solutions with concentrations between 1.24×10-7 and 1.00×10-3molL-1. The sensors are insensitive to pH between 3.5 to 11.0, they have a practical detection limit of 7.66 (±0.42) ×10-8molL-1 and a response time below 60s for solutions with perchlorate concentrations above 5×10-6molL-1. The accuracy of the results was confirmed by the analysis of the contaminant in a certified reference water sample
ChemInform Abstract: PENTAAMMINE COMPLEXES OF CHROMIUM(III) WITH GROUP V OXOANIONIC LIGANDS. I. COMPLEXES WITH LIGANDS PHOSPHATE AND DIHYDROGEN PHOSPHATE
ChemInform Abstract: BINUCLEAR COMPLEXES OF IRON(III) AND CHROMIUM(III) WITH BRIDGING CYANO LIGAND
ChemInform Abstract: A Planar, Binucleating, Pyrazole Derivative Ligand. Crystal Structure of Bis(μ-3,5-bis(2′-pyridyl)pyrazolato-N1N′:N2N′′)-bis(dimethanolnickel(II)) Dichloride Dihydrate.
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