Kinetics and mechanisms of electrochemical reactions on platinum with solutions of iodine-sodium iodide in acetonitrile

The kinetics of the iodine-tri-iodide-iodide electrode in acetonitrile has been investigated in the temperature range from 0 to 30°C. Current/voltage curves were determined using a platinum rotating disk electrode working at 200 to 3000 rpm. The anodic and cathodic current/voltage curves are characterized by two well defined waves. The total reactions related to the first and second anodic waves are respectively 3I− = I3− + 2 e and 2I3− = 3I2 + 2 e, while the reverse reactions represent the second and first cathodic waves respectively. The diffusion coefficients of the diffusing species have been evaluated. Current/voltage curves in the region preceding the limiting cd exhibit a measurable irreversibility. The kinetic parameters related to the activated process were determined, and the kinetics of the reactions interpreted in terms of reaction mechanisms that involve an ion plus atom reaction as rate determining step for the anodic process and the reverse reaction for the cathodic process.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Kinetics and mechanisms of electrochemical reactions on platinum with solutions of iodine-sodium iodide in acetonitrile

The kinetics of the iodine-tri-iodide-iodide electrode in acetonitrile has been investigated in the temperature range from 0 to 30°C. Current/voltage curves were determined using a platinum rotating disk electrode working at 200 to 3000 rpm. The anodic and cathodic current/voltage curves are characterized by two well defined waves. The total reactions related to the first and second anodic waves are respectively 3I− = I3− + 2 e and 2I3− = 3I2 + 2 e, while the reverse reactions represent the second and first cathodic waves respectively. The diffusion coefficients of the diffusing species have been evaluated. Current/voltage curves in the region preceding the limiting cd exhibit a measurable irreversibility. The kinetic parameters related to the activated process were determined, and the kinetics of the reactions interpreted in terms of reaction mechanisms that involve an ion plus atom reaction as rate determining step for the anodic process and the reverse reaction for the cathodic process.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Kinetics and mechanisms of electrochemical reactions on platinum with solutions of iodine-sodium iodide in acetonitrile

The kinetics of the iodine-tri-iodide-iodide electrode in acetonitrile has been investigated in the temperature range from 0 to 30°C. Current/voltage curves were determined using a platinum rotating disk electrode working at 200 to 3000 rpm. The anodic and cathodic current/voltage curves are characterized by two well defined waves. The total reactions related to the first and second anodic waves are respectively 3I− = I3− + 2 e and 2I3− = 3I2 + 2 e, while the reverse reactions represent the second and first cathodic waves respectively. The diffusion coefficients of the diffusing species have been evaluated. Current/voltage curves in the region preceding the limiting cd exhibit a measurable irreversibility. The kinetic parameters related to the activated process were determined, and the kinetics of the reactions interpreted in terms of reaction mechanisms that involve an ion plus atom reaction as rate determining step for the anodic process and the reverse reaction for the cathodic process.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

'Kandinsky-fying’ the law: A translaborative use of abstract art in the law classroom

Sources of law are made up of terms that, amongst other things, mediate between facts and different results, and it is the role of lawyers to explain or justify why a particular interpretation or permutation of a given term should be taken in a given case. Such terms do not exist in isolation, but are hugely contextual and play an integral role in intermediating between different potential outcomes. Therefore, the skill of carefully applying and using legal terms is one of the primary focuses of legal education and calls for a consideration of the intricate role that legal terms play in legal argumentation. However, sometimes this endeavour in the law classroom is affected by the focus placed on the meaning of individual terms, as opposed to the broader role they have in legal reasoning and the analysis of legal outcomes. In considering this, this paper draws a contrast between the way in which students sometimes use different legal and moral terms in the various roles in their lives outside of the classrooms and within, and contends that one of the reasons for this is the greater liberty that they feel in using different terms outside of the classroom. This paper contends that, pedagogically, a similar level of independence can be achieved through the collaborative translation of legal concepts into abstract art, by enabling students to take greater co-ownership of legal language. Specifically, it argues that Wassily Kandinsky’s art theory, with its emphasis on the spirit and emotions, can provide an effective framework for this

Correlation between SERS of Pyridine and Electrochemical Response of Silver Electrodes in Halide-Free Alkaline Solutions

Surface-enhanced Raman scattering (SERS) of pyridine (Py) on Ag electrodes in alkaline solutions free of halide ions was obtained at 25°C as a function of the applied potential. The Ag surface was activated for SERS through repetitive oxidation-reduction cycles (ORC), the effect being dependent on the electrochemical electrode history. The SERS effect was correlated to the activation for the hydrogen evolution reaction (HER), which can be obtained by means of potentiodynamic as well as potentiostatic procedures. The maximum SERS activity was achieved at potentials near the potential of zero charge (pzc) of polycrystalline Ag and appeared to be related to the maximum observed in the roughness factor vs potential curve. These results can be interpreted through the formation of a new uniform globular overlayer structure on the electroreduced Ag surface, which apparently exhibits a certain degree of preferred crystallographic orientation. Three well-defined potential regions can be distinguished for the complex competitive interactions between H2O, OH- ion, and Py with the new Ag electrode surface.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Individual differences in level of wisdom are associated with brain activation during a moral decision-making task.

IntroductionWisdom is reportedly associated with better health and quality of life. However, our knowledge of the neurobiology of wisdom is still in the early stages of development. We aimed to improve our understanding by correlating a psychometric measure of the trait with patterns of brain activation produced by a cognitive task theorized to be relevant to wisdom: moral decision-making. In particular, we aimed to determine whether individual differences in wisdom interact with moral task complexity in relation to brain activation.MethodsParticipants were 39 community-dwelling men and women aged 27-76 years, who completed moral and nonmoral decision-making tasks while undergoing functional magnetic resonance imaging. Brain activation in select regions of interest was correlated with participants' scores on the San Diego Wisdom Scale (SD-WISE).ResultsIndividual differences in wisdom were found to interact with brain response to moral versus nonmoral and moral personal versus impersonal dilemmas, particularly in regions in or near the default mode network. Persons with higher scores on the SD-WISE had less contrast between moral and nonmoral dilemmas and greater contrast between moral-personal and moral-impersonal dilemmas than individuals with lower SD-WISE scores.ConclusionsResults confirmed our hypothesis that individual differences in level of wisdom would interact with moral condition in relation to brain activation, and may underscore the relevance of considering one's own and others' actions and experiences in the context of wise thinking. Future studies are needed to replicate these findings and to examine specific neurocircuits

Correlation between SERS of Pyridine and Electrochemical Response of Silver Electrodes in Halide-Free Alkaline Solutions

Surface-enhanced Raman scattering (SERS) of pyridine (Py) on Ag electrodes in alkaline solutions free of halide ions was obtained at 25°C as a function of the applied potential. The Ag surface was activated for SERS through repetitive oxidation-reduction cycles (ORC), the effect being dependent on the electrochemical electrode history. The SERS effect was correlated to the activation for the hydrogen evolution reaction (HER), which can be obtained by means of potentiodynamic as well as potentiostatic procedures. The maximum SERS activity was achieved at potentials near the potential of zero charge (pzc) of polycrystalline Ag and appeared to be related to the maximum observed in the roughness factor vs potential curve. These results can be interpreted through the formation of a new uniform globular overlayer structure on the electroreduced Ag surface, which apparently exhibits a certain degree of preferred crystallographic orientation. Three well-defined potential regions can be distinguished for the complex competitive interactions between H2O, OH- ion, and Py with the new Ag electrode surface.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada