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35 results on '"Bignozzi, C.A."'

4. Anti-tumor properties of silver

Author

Candotto, V., Pezzetti, F., Bignozzi, C.A., Agazzi, A., Spadari, F., Palmieri, A., Candotto, V, Pezzetti, F, Bignozzi, C A, Agazzi, A, Spadari, F, and Palmieri, A

Subjects
antitumoral effect in vitro, silver, tumour, Settore MED/28 - Malattie Odontostomatologiche, Settore MED/29 - Chirurgia Maxillofacciale
Abstract

The use of silver dates to the period when people used it to mint coins or forge jewels. Towards the end of the 1960s, Resenmberg reported a study on the antitumor activity of cisplatin, and after a few years, cisplatin began to be used all over the world against different types of neoplasias mainly involving testes, ovaries, tumors of the district head-neck. Laryngeal carcinoma cell line HEP2 and tongue carcinoma cell lines PE15 and PE46, were cultured. Cell lines were treated with increasing concentration Ag in order to evaluate the optimal concentration levels that did not significantly affect cell viability. Basing on these data, the concentration adopted for the treatment was 0.007%. Gene expression profile was carried out for 10 genes belong to cell cycle pathways. Significantly up-regulated genes showed ≥ 2-fold change in expression while significantly down-regulated genes showed ≤ 0.5 -fold change in expression. Treatment appears to not significantly affect gene expression in the HEP2 cell line. In fact the only significantly down-regulated gene was CCNE1. All other genes have an expression comparable to that of untreated control. In recent years, the complexes containing gold and silver have been thoroughly studied for their electronic and chemical capabilities and their potential as a valid alternative in the development of new technologies. Further studies on the mechanisms of the biological effect discovered can become fundamental for the development of new high efficiency drugs with minimal minimum effects for the treatment of malignant neoplasia in humans and animals.

Published
2019

7. Four intercomponent processes in a Ru(II)-Rh(III) polypyridine dyad: electron transfer from excited donor, electron transfer to excited acceptor, charge recombination and electronic energy transfer

Author

Indelli, M. T., Bignozzi, C.A., Harriman, A., Schoonover, J.R., and Scandola, F.

Subjects
Ruthenium -- Research, Rhodium -- Research, Photochemistry -- Analysis, Chemistry
Abstract

The Ru(II)-Rh(II) binuclear complex has photoexcitable electron donor and electron acceptor units. Photoinduced electron transfer reaction involves electron transfer to excited acceptor, electron transfer from excited donor, change recombination and electronic transfer of energy. All these processes are resolved kinetically and the kinetics are controlled by the change-separation processes between normal and inverted region. A change from fluid solutions to rigid media shifts the electronic transfer to energy transfer.

Published
1994

8. A Modular Stand-Alone Photocatalytic Reactor for Waste Water Purification: The HPSolar Project

Author

Bernardoni, P., Boschetti, M., Mangherini, G., Vincenzi, D., Fugattini, S., Andreoli, A., Cristino, V., Caramori, S., and Bignozzi, C.A.

Subjects
PV Systems - Performance, Applications and Integration, Grid and Energy System Integration, Stand-Alone PV System, Stand-Alone PV System, Off-Grid, Utilities, Ambientale, Off-Grid, Utilities
Abstract

35th European Photovoltaic Solar Energy Conference and Exhibition; 1750-1753, In this work we present the construction and performances of a photocatalytic reactor developed for the HPSolar project, the purpose of this reactor is the treatment of water in order to remove pollutants like drugs or pesticides that are not removed effectively by present water treatments. The reactor is modular and composed by multiple elementary cells where the photocatalyst is a thin layer of tungsten trioxide biased positively with respect to a metallic cathode; this polarization is switched periodically in order to restore the functionality of the anode. The cells are completely self-reliant because are powered by four solar cells laying behind the semi-transparent anode while a microcontroller integrated into each cell applies the biasing cycles. The abatement measurements on atenolol and carbamazepine show that this device can remove 70% of the drugs from a sample of water within 5 and 7 hours respectively.

Published
2018

18. Efficient Anodically Grown WO3 for Photoelectrochemical Water Splitting.

Author

Caramori, S., Cristino, V., Meda, L., Tacca, A., Argazzi, R., and Bignozzi, C.A.

Subjects
TUNGSTEN oxides, CRYSTAL growth, PHOTOELECTROCHEMISTRY, WATER, CHEMICAL reactions, SOLVENTS, POTENTIOSTAT, ELECTROLYTES, SIMULATION methods & models
Abstract

Abstract: The potentiostatic anodization of metallic tungsten has been investigated in different solvent/electrolyte compositions with the aim of improving the photoelectrochemical performances of the tungsten oxide layer. Among the explored electrolytes, the anodization in the NMF/H2O/NH4F solvent mixture was found to produce the most efficient WO3 photoanodes, which, combining spectral sensitivity, high electrochemically active surface and improved charge transfer kinetics, outperform, under simulated solar illumination, most of the reported nanocrystalline substrates produced by anodization in aqueous electrolytes and by sol gel methods. While the preparation of the photoelectrodes is a slow process at room temperature (20°C), it could be greatly accelerated (x 10) by carrying out the anodization at 40-50°C, thus proving to be a fast and convenient approach to the production of high performing WO3 photoactive substrates directly connected to a metal electron collector. [Copyright &y& Elsevier]

Published
2012
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22. Sensitization of TiO2 with ruthenium complexes containing boronic acid functions

Author

Altobello, S., Bignozzi, C.A., Caramori, S., Larramona, G., Quici, Silvio, Marzanni, Giovanni, and Lakhmiri, Rajae

Subjects
*TITANIUM dioxide, *SOLAR energy, *PLATINUM group, *PHOTOVOLTAIC cells
Abstract

New ruthenium complexes based on bipyiridine and terpyridyne type ligands, containing boronic acid functions, of formulae: [Ru(bpy-Φ-B(OH)2)2(CN)2], 6, (bpy-Φ-B(OH)2 = 4-(2,2′-dipyridil)phenylboronic acid), [Ru(trpy-B(OH)2)(tb2bpy)Cl](PF6), 11, (trpy-B(OH)2 = 4-[4′-(2,2′:6′,2″-terpyridil]-boronic acid), [Ru(trpy)-Φ-B(OH)2)(tb2bpy)Cl] (PF6), 12, (trpy)-Φ-B(OH)2 = 4-[4′-(2,2′:6′,2″-terpyridil]-phenylboronic acid), have been prepared, characterized, and tested in dye-sensitized solar cells (DSSCs). The results of this first study indicate that: (i) the boronic acid function acts as interlocking group between sensitizer and mesoporous titanium dioxide; (ii) only the presence of two B(OH)2 groups/molecule allow to obtain high photoanode surface coverages with optical densities > 1; (iii) The presence of the phenyl spacer in 12 reduces the photocurrent efficiency with respect to complex 11, most probably for a reduced electronic coupling between excited sensitizer and semiconductor conduction band. The insights gained from this work suggest that better photoelectrochemical performances should be obtained with dye molecules based on bpy type ligands bearing two boronic acid functions directly bound to the aromatic ring. [Copyright &y& Elsevier]

Published
2004
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33. Mass transport and charge transfer rates for Co(III)/Co(II) redox couple in a thin-layer cell

Author

Liberatore, M., Petrocco, A., Caprioli, F., La Mesa, C., Decker, F., and Bignozzi, C.A.

Subjects
*METAL complexes, *ORGANOCOBALT compounds, *MASS transfer, *BIPYRIDINE, *OXIDATION-reduction reaction, *CHARGE transfer, *NITRILES, *DYE-sensitized solar cells
Abstract

Abstract: Recently, the complex Co(dtb)3 n+ (dtb=4,4 di tert-butyl-2,2′ bipyridine) in methoxypropionitrile (MPN) solvent has been proposed as an alternative redox mediator in the thin-layer dye sensitized solar cells. The electrochemical properties of this new mediator as a function of temperature were investigated by mean of symmetric golden electrodes thin-layer cell, using three electro-analytical techniques: electrochemical impedance spectroscopy (EIS), slow scan cyclic voltammetry (SCCV) and chronoamperometry (CA). Our study pointed out that, at room temperature, both the electron transfer rate k°=1.24 10−4 cms−1 as well as the diffusion coefficient D =5.85×10−7 cms−1 are rather low. Raising the temperature has a beneficial effect, increasing more than 6 times the standard rate constant of electron transfer and more than 3 times the ionic diffusion coefficient at 80°C. However, for all the studied temperatures, the slow mass transport of Co(III)/Co(II) species still remains the rate determining step. Viscosity measurements have demonstrated that the ionic mass transport in MPN follows the Stokes’ law and the Walden product is constant, in the temperature range investigated. [Copyright &y& Elsevier]

Published
2010
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34. Photoelectrocatalytic degradation of emerging contaminants at WO3/BiVO4 photoanodes in aqueous solution

Author

Carlo Alberto Bignozzi, Luca Pasquini, Federico Boscherini, Stefano Caramori, Alberto Piccioni, Francesco Passabi, Luisa Pasti, Nicola Marchetti, Jagadesh Kopula Kesavan, Lucia Amidani, Serena Berardi, Alessandra Molinari, Michele Orlandi, Vito Cristino, Nicola Bazzanella, Cristino V., Pasti L., Marchetti N., Berardi S., Bignozzi C.A., Molinari A., Passabi F., Caramori S., Amidani L., Orlandi M., Bazzanella N., Piccioni A., Kopula Kesavan J., Boscherini F., and Pasquini L.

Subjects
Materials science, heterojunction, genetic structures, water, photocatalytic degradation, fabrication, 02 engineering and technology, Electrolyte, x-ray absorption spectroscopy, film, 010402 general chemistry, Electrochemistry, Photochemistry, 01 natural sciences, bivo4, efficient, photocatalysi, Oxidizing agent, mineralization, Physical and Theoretical Chemistry, Visible-light, X-ray absorption spectroscopy, transformation, Aqueous solution, Ambientale, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Photocatalysis, Degradation (geology), 0210 nano-technology, Mesoporous material, Photoelectrocatalytic WO3/BiVO4
Abstract

WO3/BiVO4 films obtained by electrochemical deposition of BiVO4 over mesoporous WO3 were applied to the photoelectrochemical degradation of selected emerging contaminants (ketoprofen and levofloxacine) in aqueous solutions. The WO3/BiVO4 films in this work are characterized by a mesoporous morphology with a maximum photoconversion efficiency >40% extending beyond 500 nm in Na2SO4 electrolytes. Oxygen was found to be the dominant water oxidation product (ca. 90% faradaic yield) and no evidence for the photogeneration of OH radicals was obtained. Nevertheless, both 10 ppm levofloxacine and ketoprofen could be degraded at WO3/BiVO4 junctions upon a few hours of illumination under visible light. However, while levofloxacine degradation intermediates were progressively consumed by further oxidation at the WO3/BiVO4 interface, ketoprofen oxidation byproducts, being stable aromatic species, were found to be persistent in aqueous solution even after 15 hours of solar simulated illumination. This indicates that, due to the lower oxidizing power of photogenerated holes in BiVO4 and a different water oxidation mechanism, the employment of WO3/BiVO4 in photoelectrochemical environmental remediation processes is much less universal than that possible with wider band gap semiconductors such as TiO2 and WO3.

Published
2019

35. Modification of Nanocrystalline WO3 with a Dicationic Perylene Bisimide: Applications to Molecular Level Solar Water Splitting

Author

Maurizio Prato, Roberto Argazzi, Stefano Caramori, Zois Syrgiannis, Carlo Alberto Bignozzi, Vito Cristino, Federico Ronconi, Aurelio Bonasera, Ronconi, Federico, Syrgiannis, Zoi, Bonasera, Aurelio, Prato, Maurizio, Argazzi, Roberto, Caramori, Stefano, Cristino, Vito, Bignozzi, Carlo Alberto, Ronconi F., Syrgiannis Z., Bonasera A., Prato M., Argazzi R., Caramori S., Cristino V., and Bignozzi C.A.

Subjects
Models, Molecular, Molecular Conformation, Nanoparticle, Imides, Photochemistry, Biochemistry, Tungsten, Catalysis, NO, Catalysi, Electron Transport, chemistry.chemical_compound, Colloid and Surface Chemistry, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, WO3, ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION, perylene, Photoelectrochemical cell, IrO2, Quenching (fluorescence), Chemistry (all), charge transfer, Water, Oxides, General Chemistry, Photochemical Processes, Solar fuel, Nanocrystalline material, perylene, WO3, charge transfer, IrO2, Microsecond, chemistry, Water Splitting, Sunlight, VISIBLE-LIGHT, ARTIFICIAL PHOTOSYNTHESIS, PHOTOELECTROCHEMICAL CELL, OXIDATION CATALYSTS, ELECTRON-TRANSFER, FABRICATION, Nanoparticles, Perylene bisimide, Water splitting, Perylene, MathematicsofComputing_DISCRETEMATHEMATICS
Abstract

[(N,N?-Bis(2-(trimethylammonium)ethylene) perylene 3,4,9,10-tetracarboxylic acid bisimide)(PF6)2] (1) was observed to spontaneously adsorb on nanocrystalline WO3 surfaces via aggregation/hydrophobic forces. Under visible irradiation (? > 435 nm), the excited state of 1 underwent oxidative quenching by electron injection (kinj > 108 s-1) to WO3, leaving a strongly positive hole (Eox ? 1.7 V vs SCE), which allows to drive demanding photo-oxidation reactions in photoelectrochemical cells (PECs). The casting of IrO2 nanoparticles (NPs), acting as water oxidation catalysts (WOCs) on the sensitized electrodes, led to a 4-fold enhancement in photoanodic current, consistent with hole transfer from oxidized dye to IrO2 occurring on the microsecond time scale. Once the interaction of the sensitizer with suitable WOCs is optimized, 1/WO3 photoanodes may hold potentialities for the straightforward building of molecular level devices for solar fuel production.

Published
2015

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