Search results for "uso"
showing 10 items of 1400 documents
Deuterium isotope effect on the induction period of the cerium catalyzed Belousov-Zhabotinsky reaction
2009
Abstract In this work we present results about the deuterium isotopic effect on the global kinetics of a cerium catalyzed Belousov–Zhabotinsky reaction. A nonlinear dependence of the induction period upon the percentage of deuterated reactants was found in batch conditions. In order to understand this result, we investigated two reaction pathways responsible for the length of the induction period, namely: (a) the reaction between the enolic form of the malonic acid with molecular bromine and (b) the oxidation of malonic acid by the Ce(IV) ion. In both cases we obtained a linear dependence of the kinetic constants on the percentage of deuterated reactants. Nevertheless, by inserting the expe…
New Features in the dynamics of a ferroin-catalyzed Belousov-Zhabotinsky reaction induced by a zwitterionic surfactant
2008
Abstract Interactions between reaction–diffusion systems and aggregated host environments are a subject of widespread interest. In this work, the behavior of the Belousov–Zhabotinsky reaction was investigated in a micellar environment formed by the zwitterionic surfactant N-tetradecyl-N,N-dimethylamine oxide (C14DMAO). The appearance of an induction period with a threshold-like dependence upon the surfactant concentration, was detected at [C14DMAO] = 5.0 × 10−3 mol dm−3. These new features were explained in terms of the segregation ability typical of the amphiphilic self-assembling systems. Numerical simulations were also performed to confirm the proposed mechanism.
Chemical waves and pattern formation in the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/water lamellar system
2004
ChemInform Abstract: Asymmetric Allylation/Pauson-Khand Reaction: A Simple Entry to Polycyclic Amines. Application to the Synthesis of Aminosteroid A…
2014
Asymmetric allylation of o-iodoarylsulfinylimines has been achieved in high diastereoselectivities. The thus-obtained o-iodoarylhomoallylic sulfinamides participate in a subsequent Sonogashira coupling followed by a diastereoselective intramolecular Pauson–Khand reaction. In this way, tricyclic amines showing a unique benzo-fused indenyl backbone were obtained. The methodology has been applied to the synthesis of amino steroid analogues.
When Violence Can Appear With Different Male Partners: Identification of Resilient and Non-resilient Women in the European Union
2018
Introduction: Little scholarly attention has been paid to the analysis of the history of intimate partner violence (IPV) against women with different male partners and how it could be related to levels of IPV with the current male partner. From this point of view, been a victim of IPV could increase the vulnerability of women and, therefore, exert a negative influence on the selection of partners over time, thus increasing the odds of potentially mating with abusive male partners. Alternatively, for some women victims of IPV in previous relationships, there may be additional resources that reduce their vulnerability to victimization by new partners. Methodology: The present study analyzes l…
Esperienze sfavorevoli infantili ed esiti psicopatologici: cluster analysis su campioni clinici e non clinici mediante la Childhood Experience of Car…
2012
Gli eventi traumatici esperiti durante l’infanzia hanno un’influenza rilevante sulla strutturazione del Sé nascente del bambino (Bifulco & Moran,1998; Jurist et al., 2008; Schimmenti & Bifulco, 2008). L’impatto di tali eventi e i loro possibili esiti psicopatologici variano in maniera significativa in relazione alla presenza simultanea di molteplici e pervasive esperienze negative e all’età in cui esse si verificano (Cook et al., 2005; van der Kolk, 2005). Questo contributo propone un’analisi esplorativa finalizzata ad individuare, attraverso la metodologia della cluster analysis, tipologie rappresentative dei diversi pattern di esperienze sfavorevoli infantili. Vengono, inoltre, analizzate…
Maltrattamento, abuso, stili relazionali e DCA, quale collegamento? Uno studio preliminare con la Childhood Experience of Care and Abuse - CECA
2012
CISV-kesäkylä kulttuurienvälisenä kasvattajana ja kokemuksellisen oppimisen mahdollistajana : kesäkylän vaikutukset 12-13-vuotiaiden oppilaiden koulu…
2009
Pauson-Khand reaction of internal dissymmetric trifluoromethyl alkynes. Influence of the alkene on the regioselectivity.
2014
Abstract: The scope of the Pauson-Khand reaction (PKR) of internal trifluoromethyl alkynes, previously described with norbornadiene, is expanded to norbornene and ethylene. A thorough structural analysis of the resulting PK adducts has been carried out to unveil that α-trifluoromethylcyclopentenones are preferred in all cases, independently of the electronic properties of the alkyne. The regioselectivity observed with norbornadiene and ethylene is higher than in the case of norbornene.
Un estudio del contenido científico de las preguntas formuladas por estudiantes cuando intentan comprender dispositivos experimentales
2013
RESUMEN: Se muestra un análisis descriptivo del contenido científico de las preguntas formuladas por estudiantes de secundaria y universitarios, cuando tratan de comprender el funcionamiento de dispositivos experimentales. Se consideran tres situaciones didácticas habituales: leer un texto acompañado de imágenes estáticas (esquemáticas); visualizar imágenes dinámicas (video o demostración de cátedra), observar y manipular los dispositivos. Solo una tercera parte de las preguntas de los estudiantes contuvieron algún término científico, aunque los universitarios superaron claramente a los de secundaria. Las leyes y principios científicos, necesarios para modelizar y explicar la realidad, apen…