443 research outputs found
Inauguració ISSE 2016
No full textActe d'inauguració del 'XVI International Summer School on the Environment (ISSE 2016)' a càrrec del Dr. Jörg Zimmer, vicerector de Política Internacional, del Sr. Ferran Miralles Sabadell, director general de Polítiques Ambientals de la Generalitat de Catalunya i de la Dra. Anna M. Geli, coordinadora de l'ISSE 20164406.mp4
4406.mp
La crisi energètica: significat i importància del Peak Oil
No full textIntervenció del Dr. en Física Antonio Turiel, en el marc de l' XI International Summer School on the Environment (ISSE 2011) sobre la problemàtica del Peak Oil i la gran escassetat2199.mp4
2199.mp
Analisi dell’efficacia della laser-terapia su 88 adenomi colo-rettali
No full textTitolo della relazione: "La terapia dei polipi cancerizzati del retto"
Presidente della Sessione scientifica "Chirurgia endoscopica delle lesioni neoplastiche precoci"
relatore nella sessione "SIED-ISSE: opinioni a confronto
Taula rodona: cap a una política integral de canvi climàtic a l'àmbit local i regional
No full textTaula rodona que reflexiona sobre una política integral de canvi climàtic a l' àmbit local i regional, en el marc de l' XI International Summer School on the Environment (ISSE 2011). Hi participen: Jordi Figueras, cap d' Àrea de sostenibilitat de l' Ajuntament de Girona, Ramon Rabella, cap de l' Oficina de Canvi Climàtic de la Diputació de Barcelona, Steffen Riess, Innovation Academy, Ignasi Puig, ambientòleg i Antonio M. Turiel, científic titular de l' Institut de Ciències del Mar del CSIC. Debat moderat per Sergi Nuss, doctorand de l' Institut de Medi Ambient de la Universitat de Girona2234.mp4
2234.mp
Inauguració del curs 2013-2014
No full textActe de benvinguda i presentació de la XIII International Summer School on the Environment (ISSE 2013), celebrat a la Universitat de Girona el 12 i 13 de setembre de 20133209.mp4
3209.mp
Electrocatalytic Reduction of Bromothiophenes on Gold and Silver Electrodes: an Example of Synergism in Electrocatalysis
No full textThe reductive cleavage of C–Br bonds on silver electrodes can be regarded as an ideal model of dissociative electron transfer (DET) in electrocatalytic conditions, modulated by many factors, among which the molecular structure is of particular relevance. A detailed mechanistic study based on a large set of compounds with different molecular structures allowed us a full rationalization of the process for the case of aryl bromides in acetonitrile. [1]
Now we are extending this research to heteroaromatic halides, in which the heteroatom not only makes the aromatic ring asymmetric from the perspective of the electron density but also can have its own specific interactions with the electrode surface, in addition to those of the halide ions. [2] As a first approach, we have selected the mono-, di-, tri- and tetra-bromothiophene series, plus a series of substituted bromothiophenes together with the corresponding bromobenzenes as benchmarks, investigating (by CV, supported by EIS in selected cases) the electrochemical reduction of the whole family: (i) on glassy carbon, GC, assumed as a non-catalytic reference electrode accounting for intrinsic reactivity; (ii) on the highly catalytic silver electrode; (iii) on gold electrode, showing in former halide cases lower catalytic effects than silver but having the highest affinity for the sulphur atom in the thiophene ring. While the results on GC and on Ag are fully consistent with the formerly studied aryl bromide case on the same two electrodes [1] the catalytic effects of Au appear to be neatly modulated by the relative position of the Br leaving group with respect to the sulphur atom. This feature is quite evident and reproducible in the whole series (including polysubstituted cases provided by our organic partner group), and points to the S atom acting as an asymmetrically anchoring group for the molecule on the Au surface.
[1] S. Arnaboldi, A. Gennaro, A.A. Isse, P.R. Mussini (2015) Electrochimica Acta, 158, 427-436
[2] S. Arnaboldi, A. Bonetti, E. Giussani, P.R. Mussini, T. Benincori, S. Rizzo, A.A. Isse, A. Gennaro (2014) Electrochemistry Communications, 38, 100-10
Dissociative electron transfer mechanism and application in the electrocatalytic activation of organic halides
No full textThe electrochemical dehalogenation of organic halides has been a widely investigated topic in primis for fundamental in- vestigations of dissociative electron transfer (DET) and as a green way for the electrosynthesis of organic compounds and environmental remediation. The main drawback associated with the electrochemical activation of C-X is the very negative potentials required, and this is particularly true in the case of organic chlorides, which represent the most investigated ensemble among organic molecules containing a leaving group. This has boosted over the last decades the research of electrode materials that are active toward C-X bond breaking, and without any doubt, Ag possesses extraordinary electro- catalytic properties, so far unsurpassed by any other electrode material. In this paper, we will attempt to brush up on important concepts related to DET in organic halides, while also evalu- ating recent developments in terms of electrode materials used in electrosynthesis based on organic halides and R-X degra- dation processes
Presentació de les jornades i Tendències en la incorporació de l'Educació per a la sostenibilitat a la Universitat
No full textActe de presentació del 'XVI International Summer School on the Environment (ISSE 2016)' i sessions a càrrec d'Anna M. Geli, de la Universitat de Girona; Mercè Junyent , de la Universitat Autònoma de Barcelona i David Alba, de la Universitat Autònoma de Madrid sobre les tendències en la incorporació de l'educació per a la sostenibilitat a la Universitat. L'Anna M.Geli i la Mercè Junyent centren la seva intervenció en els objectius del desenvolupament sostenible, la construcció d'una universitat sostenible, la recerca per incorporar la sostenibilitat en el currículum universitari, el treball en xarxa de les universitats i iniciatives en relació a competències per al desenvolupament professional en l'Educació per a la sostenibilitat. En David Alba parla sobre indicadors de sostenibilitat4405.mp4
4405.mp
Iterative Soft Sequential Estimation assisted acquisition of <i>m</i>-sequences
No full textA novel iterative soft sequential-estimation (ISSE) method is proposed for the acquisition of m-sequences. The ISSE algorithm is designed based on the principle of iterative soft-in-soft-out (SISO) decoding. The employment of the proposed ISSE acquisition scheme is particularly beneficial for the acquisition of long m-sequences. Results demonstrate that a chip signal-to-noise ratio reduction of 10 dB is achievable at an erroneous acquisition probability of 10-4
Potentialities and Peculiarities of Polycrystalline Silver as an Electrocatalytic Material for Organic Halide Detection
No full textThe impressive catalytic properties of polycrystalline silver electrodes for the cleavage of the C-X bond in organic halides (X = Cl, Br, I) have been the object of extensive investigations by our joint groups in the last years. The process can be interpreted, in the frame of the Marcus-Savéant theory, in terms of a concerted dissociative electron transfer hinging on a three-center intermediate including the metal surface, and results in huge anticipations of the reduction potentials (even >1 V with respect to the non-catalytic GC electrode). The electrocatalytic properties of the metal surface are widely modulated by the molecular structure, the presence of functional groups on the substrate and the reaction medium, both in terms of the nature of the solvent and the size of the tetralkylammonium cation of the supporting electrolyte. Such properties are extremely appealing not only in view of synthetic applications (affording milder reaction conditions and alternative reaction products), but also in the analytical and environmental fields, for the detection of trace amounts of organic halides. In fact the catalytic activity of silver specifically applies to the above halide functional groups, making possible easy detection at Ag of voltammetric signals, which otherwise, at non-catalytic electrodes, are partially or totally covered by the background limiting current. Most organic halides, including alkyl chlorides that are hardly detectable at conventional electrodes, give rise to neat peaks at Ag at potentials well before cathodic limit. Another important advantage of this electrode material is that it promotes peak differentiation in mixed samples, thanks to the modulation of the electrocatalytic properties by the molecular structure of RX. Moreover, protic solvents, including water, appear to enhance such catalytic activity. A series of model cases will be presented and discussed (concerning both qualitative and quantitative analysis topics), together with the optimized protocol for preparation and management of the silver surfaces
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