Influence of the surface adsorption–desorption processes on the ignition curves of volatile organic compounds (VOCs) complete oxidation over supported catalysts

The simplicity to obtain ignition curves has resulted in their extended use for the measurement of the catalysts activity in the complete oxidation of VOCs. However, we have found that this method gives incorrect results for some systems, such as conversions greater than 100% or disagreements between the conversion values calculated through the concentration change of the reactants and the products, which can lead to misunderstandings. Toluene oxidation over reduced Pd/Al2O3 and acetone oxidation over supported Mn2O3 have presented those features. The study of these systems has been carried out performing DRIFTS spectra under reaction conditions and TPD experiments. The effect of the start-up procedure of the complete oxidation reactions has been considered as well. After discarding the formation of partial oxidation products and the hydrogen retention on Pd as possible causes, the adsorption–desorption processes of VOCs, surface intermediates and CO2 were considered. It can be concluded that when the activity of the active phase supported on the Al2O3 is high enough to allow the coupling at relatively low temperature of combustion with the adsorption and desorption processes of toluene or acetone and CO2, a sort of chain reaction occurs leading to CO2 peaks.Fil: Paulis, María. Universidad del País Vasco; EspañaFil: Gandia Pascual, Luis Maria. Universidad Pública de Navarra. Departamento de Química Aplicada; EspañaFil: Gil Bravo, Antonio. Universidad Pública de Navarra. Departamento de Química Aplicada; EspañaFil: Sambeth, Jorge Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Odriozola, Jose Antonio. Universidad de Sevilla. Departamento de Química Inorgánica e Instituto de Ciencias de Materiales; EspañaFil: Montes Ramirez, Mario. Universidad del País Vasco; Españ

Delay Spread Estimation using a Game Engine Ray Based Model in Indoor Scenario at 5 GHz

[EN] In this paper we show the results of a simulation of channel parameters using a Game Engine Ray based tool, developed by our group, which has been evolving during last few years. We show simulation results and compare it with a set of measurements for an indoor scenario, in the band of 5.4 GHz. We found a good match between the rays based tool and measurements for Delay Spread. Also, we show the use of an Open Source 3D modelling tool for the scenario building, showing the flexibility of the XML description language for this kind of scenarios.ANDRÉS NAVARRO CADAVID; Guevara, D.; Escalante, D.; Vargas, J.; Gómez, J.; Cardona Marcet, N.; Gimenez Gandia, JJ. (2016). Delay Spread Estimation using a Game Engine Ray Based Model in Indoor Scenario at 5 GHz. Journal of Engineering and Applied Sciences. 11(5):3380-3384. http://hdl.handle.net/10251/94540S3380338411

Pharmacokinetics of Didanosine in Antepartum and Postpartum Human Immunodeficiency Virus-Infected Pregnant Women and Their Neonates: An AIDS Clinical Trials Group Study

Didanosine (ddI) pharmacokinetics in antepartum and postpartum human immunodeficiency virus (HIV)—infected women and their neonates were studied. HIV-infected pregnant women received an intravenous (iv) ddI infusion (1.6 mg/kg/h) or an oral dose (200 mg bid or 125 mg bid) at 31 weeks antepartum and 6 weeks postpartum. Blood samples were obtained regularly up to 6 or 8 h after drug administration. The same oral dose of ddI (bid) was administered until labor began. Then, ddI was infused iv until delivery. An oral pharmacokinetic study (60 mg/m2) was conducted in infants at day 1 and at week 6 after birth. Plasma concentrations of ddI were measured by radioimmunoassay. After iv ddI administration, only the maternal plasma clearance was found to be significantly increased antepartum (1028 ±231 mL/min) versus postpartum (707 ± 213 mL/min). No pharmacokinetic parameters after oral administration were significantly affected by pregnancy. The pharmacokinetics of ddI in the neonates were highly variable. We conclude that the oral ddI dose need not be adjusted during pregnancy

β-arrestin signalling and bias in hormone-responsive GPCRs

International audienceG protein-coupled receptors (GPCRs) play crucial roles in the ability of target organs to respond to hormonal cues. GPCRs’ activation mechanisms have long been considered as a two-state process connecting the agonist-bound receptor to heterotrimeric G proteins. This view is now challenged as mounting evidence point to GPCRs being connected to large arrays of transduction mechanisms involving heterotrimeric G proteins as well as other players. Amongst the G protein-independent transduction mechanisms, those elicited by β-arrestins upon their recruitment to the active receptors are by far the best characterized and apply to most GPCRs. These concepts, in conjunction with remarkable advances made in the field of GPCR structural biology and biophysics, have supported the notion of ligand-selective signalling also known as pharmacological bias. Interestingly, recent reports have opened intriguing prospects to the way β-arrestins control GPCR-mediated signalling in space and time within the cells. In the present paper, we review the existing evidence linking endocrine-related GPCRs to β-arrestin recruitement, signalling, pathophysiological implications and selective activation by biased ligands and/or receptor modifications. Emerging concepts surrounding β-arrestin-mediated transduction are discussed in the light of the peculiarities of endocrine systems