Bruno Vodopivec | Università degli Studi di Milano-Bicocca (original) (raw)

Papers by Bruno Vodopivec

Macromolecules, 2003

The dynamic processes in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer, lea... more The dynamic processes in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer, lead lanthanum zirconate titanate (PLZT)-P(VDF-TrFE) composite, electron-irradiated P(VDF-TrFE) copolymer, and poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer have been studied by measurements of the temperature and frequency-dependent linear (1) and third-order nonlinear (3) dielectric constants. While a paraelectric-to-ferroelectric transition takes place in the crystalline region of the nonirradiated copolymer and composite, electron-irradiated P(VDF-TrFE) copolymer and P(VDF-TrFE-CFE) terpolymer show a significantly different dielectric response: a broad frequency dispersion in 1 and 3, asymmetric temperature evolution of the relaxation spectrum as the longest relaxation time diverges at a finite freezing temperature while the shortest relaxation times remain active down to the lowest temperatures, and a paraelectric-to-glass crossover in the temperature dependence of the dielectric nonlinearity a3) 3/ 0 3 1 4. All these properties, together with the temperature dependence of the static field cooled dielectric constant, are very similar to those observed in the classical relaxor systems and are reminiscent of the dynamic behavior observed in various spin glasses. Thus, additional confirmation that giant electrostrictive response of the electron-irradiated P(VDF-TrFE) copolymer and P(VDF-TrFE-CFE) terpolymer is the consequence of their relaxor-like structure is obtained.

Journal of the European Ceramic Society, 2004

The linear and third harmonic nonlinear dielectric constants were measured in 6.5/65/35 PLZT hot-... more The linear and third harmonic nonlinear dielectric constants were measured in 6.5/65/35 PLZT hot-pressed ceramics. Linear dielectric data obtained on ooling show the transition from an ergodic to a nonergodic relaxor phase while, on heating, a ferroelectric to ergodic relaxor phase transition appears. The third harmonic di-electric response is reminiscent of an ergodic to nonergodic relaxor phase transition. Existence of the spontaneous polarization below the Vogel–Fulcher temperature at which the longest relaxation time diverges, indicates the possibility that the sample breaks up at low temperatures into relaxor glass-like and ferroelectric order dominated regions.

Journal of the European Ceramic Society, 2004

... 19. It should also be noted that P S vanishes at the same temperature where the sharp peak in... more ... 19. It should also be noted that P S vanishes at the same temperature where the sharp peak in pyroelectric current is observed. ... In this case a more sharp first order ferroelectric phase transition exhibiting a divergence in the dielectric response should be seen. ...

Ferroelectrics, 2003

The temperature dependence of the complex dielectric constant was studied in electron irradiated ... more The temperature dependence of the complex dielectric constant was studied in electron irradiated Poly (Vinylidene Fluoride-Trifluoroethylene) (P(VDF/TrFE)) copolymer with composition of 75 mol% vinylidene fluoride VF 2 (PVDF75). Besides the ferroelectric transition at ∼323 K, the analysis of data by the temperature-frequency plot demonstrates that PVDF75 below ferroelectric transition shows a dielectric relaxation which is typical of the glassy behavior observed in relaxor systems. The dielectric relaxation exhibits a broad distribution of relaxation times whose polydispersity increases with decreasing temperature. The divergence of the longest relaxation time occurs at the freezing temperature T f ∼ 198 K, which indicates the coexistence of relaxor and ferroelectric phases below T f in this system.

ChemInform, Aug 22, 2010

ABSTRACT Reaction of anodically generated thiocyanogen (NaSCN, LiClO4, MeCN, Pt, 0.9V vs SCE) wit... more ABSTRACT Reaction of anodically generated thiocyanogen (NaSCN, LiClO4, MeCN, Pt, 0.9V vs SCE) with 3-alkylsubstituted indoles results preferentially in isothiocyanation at the indole 2-position rather than in the expected thiocyanation.

ChemInform, Aug 20, 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In this work, a new method for Cu(In,Ga)Se2 thin film growth has been tested, which is different ... more In this work, a new method for Cu(In,Ga)Se2 thin film growth has been tested, which is different from the common co-evaporation and sputtering processes. The purpose of the deposition method proposed is to find a solution that combines the advantages of the sputtering and evaporation solutions for a scalable process to an industrial level. The system object of the paper allows to realize an indirect deposition of the film by sputtering to the substrate. In particular, metal precursors, with the desired ratio, are initially deposited in an area characterized by inert atmosphere, without vapors of selenium, on one or more cylindrical bodies used for the transfer. When the material deposited on the cylindrical bodies is located - as a result of the movement of rotation of the latter - in front of the substrate, where a Se atmosphere is present, it is evaporated by means of localized heating. At the moment, with the new procedure an efficiency of 14.8% has been reached on glass.

Radiation Effects and Defects in Solids, 2010

... a , Dimitri Batani a * , Yas Al Hadithi a , Rashida Jafer a , Luca Antonelli a , Bruno Vodopi... more ... a , Dimitri Batani a * , Yas Al Hadithi a , Rashida Jafer a , Luca Antonelli a , Bruno Vodopivec a , Marialuisa Vitobello b & Munawar Iqbal c pages 501-508. ... in 1986 11. Adrian, FJ, Bohandy, J., Kim, BF, Jette, AN and Thompson, P. 1987. J. Vac. Sci. Technol. B , 5: 1490–1494. ...

Physical Review B, 2009

We have identified, in erbium-doped silica with SnO 2 nanocrystals, excitation-diffusion processe... more We have identified, in erbium-doped silica with SnO 2 nanocrystals, excitation-diffusion processes restricted to the single nanocrystal. Time-resolved measurements of erbium infrared luminescence excited by energy transfer via nanocrystal excitation, together with the identification and quantification of the nanophase-related Er 3+ variety by its electron paramagnetic resonance, have allowed us to analyze the dependence of the excitation decay rate on the number of ions per nanoparticle and to reveal the effects of the discrete spatial domain composed by nanocrystals. Finally, a nonlinear relation is derived to describe the effects of Förster energy transfer in disconnected nanosystems.

The Journal of Organic Chemistry, 1997

Palinavir is a potent peptidomimetic-based HIV protease inhibitor. We have developed a highly con... more Palinavir is a potent peptidomimetic-based HIV protease inhibitor. We have developed a highly convergent and stereoselective synthesis which is amenable to the preparation of multikilogram quantities of this compound. The synthetic sequence proceeds in 24 distinct ...

Journal of Non-Crystalline Solids, 2009

Photoluminescence in fluorine-modified Sn-doped silica has been analyzed by means of synchrotron ... more Photoluminescence in fluorine-modified Sn-doped silica has been analyzed by means of synchrotron radiation in the UV and vacuum-UV, from 120 to 330 nm, looking at the optical activity of oxygen-deficient-centers ODC(II) in Sn-substituted cationic sites. The comparison between F-modified Sn-doped samples and previous data on F-free Sn-doped material evidences differences in the intensity of the 3.2 eV emission band excited at 3.7 eV, and in the thermal dependence of the intensity of this emission excited via intersystem crossing. The role of fluorine in modifying the optical activity of ODC(II) and in the SnO 2 clustering is discussed, showing that an efficient excitation transfer may be activated from SnO 2 to the Sn-variant of ODC(II).

CuInSe2-based solar cells showed long-term stability and the highest conversion efficiencies amon... more CuInSe2-based solar cells showed long-term stability and the highest conversion efficiencies among thin film solar cells, overcoming 20%. The optoelectronic properties of the absorber layers and interfaces are strongly dependent upon the deposition method and strictly related to the solar cell efficiency. In this work, an alternative approach for CIGS thin film growth has been developed and tested. Such approach consists of sputtering deposition of the metal elements combined with selenium co-evaporation, which allows deposition time of the CIGS layer lower than 30 min, matching industrial application requirements. The relationships between the growth parameters of such hybrid sputtering/evaporation method and the chemical-physical properties of the CIGS films have been studied. The CIGS cell performances have been monitored by External Quantum Efficiency measurements and I-V measurements. Test solar cells of 0.5 cm2 have shown an efficiency of 14 % on glass substrates.

Annali di chimica, 2001

The possibility of oxidizing at a PbO2 anode the phenols and polyphenols, present in the olive oi... more The possibility of oxidizing at a PbO2 anode the phenols and polyphenols, present in the olive oil mill wastewater, has been studied as a pretreatment for the submission of such wastewater to the traditional biological treatments. The results obtained operating at current densities ranging 500 to 2000 A/m2 show that it is possible to reduce the concentration of the phenolic components, which interfere with the biological treatments, down to low values without decreasing too much the total organic content of the wastewater.

Biochemistry Usa, 1999

The polymerization of hemoglobin-derived ferric-protoporphyrin IX [Fe(III)PPIX] to inert hemozoin... more The polymerization of hemoglobin-derived ferric-protoporphyrin IX [Fe(III)PPIX] to inert hemozoin (malaria pigment) is a crucial and unique process for intraerythrocytic plasmodia to prevent heme toxicity and thus a good target for new antimalarials. Quinoline drugs, i.e., chloroquine, and non-iron porphyrins have been shown to block polymerization by forming electronic pi-pi interactions with heme monomers. Here, we report the identification of ferrous-protoporphyrin IX [Fe(II)PPIX] as a novel endogenous anti-malarial. Fe(II)PPIX molecules, released from the proteolysis of hemoglobin, are first oxidized and then polymerized to hemozoin. We obtained Fe(II)PPIX on preparative scale by electrochemical reduction of Fe(III)PPIX, and the reaction was monitored by cyclic voltammetry. Polymerization assays at acidic pH were conducted with the resulting Fe(II)PPIX using a spectrophotometric microassay of heme polymerization adapted to anaerobic conditions and the products characterized by infrared spectroscopy. Fe(II)PPIX (a) did not polymerize and (b) produced a dose-dependent inhibition of Fe(III)PPIX polymerization (IC(50) = 0.4 molar equiv). Moreover, Fe(II)PPIX produced by chemical reduction with thiol-containing compounds gave similar results: a dose-dependent inhibition of heme polymerization was observed using either L-cysteine, N-acetylcysteine, or DL-homocysteine, but not with L-cystine. Cyclic voltammetry confirmed that the inhibition of heme polymerization was due to the Fe(II)PPIX molecules generated by the thiol-mediated reduction of Fe(III)PPIX. These results point to Fe(II)PPIX as a potential endogenous antimalarial and to Fe(III)PPIX reduction as a potential new pharmacological target.

... THIOCYANATION OF 3ALKYLOOLFS: AN UNEXPECTEDLY EASY ACCESS TO 2ISOTHIOCYANO DERIVATIVES Giovan... more ... THIOCYANATION OF 3ALKYLOOLFS: AN UNEXPECTEDLY EASY ACCESS TO 2ISOTHIOCYANO DERIVATIVES Giovanni PAUMISANO,*' Elisabetta BRENNA, Bruno DANI.I ... been proposed as steps in rearrangement reactions, see : Battye, PJ.; Jones, DW; Tucker, ...

ABSTRACT The interaction of 40 ps pulse duration laser emitting at 532 nm wavelength with human d... more ABSTRACT The interaction of 40 ps pulse duration laser emitting at 532 nm wavelength with human dental tissue (enamel, dentin, and dentin–enamel junction) has been investigated. The crater profile and the surface morphology have been studied by using a confocal auto-fluorescence microscope (working in reflection mode) and a scanning electron microscope. Crater profile and crater morphology were studied after applying consecutive laser pulses and it was found that the ablation depth increases with the number of consecutive pulses, leaving the crater diameter unchanged. We found that the thermal damage is reduced by using short duration laser pulses, which implies an increased retention of restorative material. We observe carbonization of the irradiated samples, which does not imply changes in the chemical composition. Finally, the use of 40 ps pulse duration laser may become a state of art in conservative dentistry.

Tetrahedron Letters, 1992

ABSTRACT Reaction of anodically generated “halonium” species (Lix or Bu4NX, LiClO4, MeCN, Pt/Pt; ... more ABSTRACT Reaction of anodically generated “halonium” species (Lix or Bu4NX, LiClO4, MeCN, Pt/Pt; I2, LiClO4, MeCN ) with pyrimidine bases and their nucleosides leads to 5-halo compounds in good yields

Journal of the European Ceramic Society, 2007

ABSTRACT

European Journal of Mineralogy, 2012

ABSTRACT The present work reports on the investigation of oxidation states, local symmetry, and o... more ABSTRACT The present work reports on the investigation of oxidation states, local symmetry, and optical properties of manganese and iron species in natural cordierite (Mg, Fe)2Al4Si5O18, by means of energy-dispersive X-ray fluorescence, electron paramagnetic resonance (EPR), photoluminescence (PL) and optical absorption techniques. In particular, specific EPR characteristics show the presence of distinct Mn2+ octahedral sites in the crystal lattice, and a small amount of Mn4+ ions in tetrahedral sites. The absence of EPR signal ascribable to Mn4+ in octahedral sites turns out to be consistent with the lack of narrow PL lines from d 3 ions in octahedral crystal field (CF). Evidence of Mn3+ in octahedral sites is instead found in steady-state and time-resolved PL measurements. EPR spectra give further details on iron site occupancy, showing the occurrence of Fe3+ ions in octahedral sites. Characteristics ascribable to all the identified metal species have been found in the optical absorption spectrum or in the PL excitation spectrum, as arising from the expected CF transitions of Fe2+, Fe3+, Mn2+, Mn3+, and Mn4+ ions. Interestingly, the results show a polarization-dependent correlation between the manganese luminescence and the pleochroic absorption band at about 17,000 cm−1. This result reveals a pleochroic contribution from the Mn3+ spin-allowed 5E→5T2 transition under the visible pleochroic band attributed to Fe2+(oct)→Fe3+(tet) transitions.

Macromolecules, 2003

The dynamic processes in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer, lea... more The dynamic processes in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer, lead lanthanum zirconate titanate (PLZT)-P(VDF-TrFE) composite, electron-irradiated P(VDF-TrFE) copolymer, and poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer have been studied by measurements of the temperature and frequency-dependent linear (1) and third-order nonlinear (3) dielectric constants. While a paraelectric-to-ferroelectric transition takes place in the crystalline region of the nonirradiated copolymer and composite, electron-irradiated P(VDF-TrFE) copolymer and P(VDF-TrFE-CFE) terpolymer show a significantly different dielectric response: a broad frequency dispersion in 1 and 3, asymmetric temperature evolution of the relaxation spectrum as the longest relaxation time diverges at a finite freezing temperature while the shortest relaxation times remain active down to the lowest temperatures, and a paraelectric-to-glass crossover in the temperature dependence of the dielectric nonlinearity a3) 3/ 0 3 1 4. All these properties, together with the temperature dependence of the static field cooled dielectric constant, are very similar to those observed in the classical relaxor systems and are reminiscent of the dynamic behavior observed in various spin glasses. Thus, additional confirmation that giant electrostrictive response of the electron-irradiated P(VDF-TrFE) copolymer and P(VDF-TrFE-CFE) terpolymer is the consequence of their relaxor-like structure is obtained.

Journal of the European Ceramic Society, 2004

The linear and third harmonic nonlinear dielectric constants were measured in 6.5/65/35 PLZT hot-... more The linear and third harmonic nonlinear dielectric constants were measured in 6.5/65/35 PLZT hot-pressed ceramics. Linear dielectric data obtained on ooling show the transition from an ergodic to a nonergodic relaxor phase while, on heating, a ferroelectric to ergodic relaxor phase transition appears. The third harmonic di-electric response is reminiscent of an ergodic to nonergodic relaxor phase transition. Existence of the spontaneous polarization below the Vogel–Fulcher temperature at which the longest relaxation time diverges, indicates the possibility that the sample breaks up at low temperatures into relaxor glass-like and ferroelectric order dominated regions.

Journal of the European Ceramic Society, 2004

... 19. It should also be noted that P S vanishes at the same temperature where the sharp peak in... more ... 19. It should also be noted that P S vanishes at the same temperature where the sharp peak in pyroelectric current is observed. ... In this case a more sharp first order ferroelectric phase transition exhibiting a divergence in the dielectric response should be seen. ...

Ferroelectrics, 2003

The temperature dependence of the complex dielectric constant was studied in electron irradiated ... more The temperature dependence of the complex dielectric constant was studied in electron irradiated Poly (Vinylidene Fluoride-Trifluoroethylene) (P(VDF/TrFE)) copolymer with composition of 75 mol% vinylidene fluoride VF 2 (PVDF75). Besides the ferroelectric transition at ∼323 K, the analysis of data by the temperature-frequency plot demonstrates that PVDF75 below ferroelectric transition shows a dielectric relaxation which is typical of the glassy behavior observed in relaxor systems. The dielectric relaxation exhibits a broad distribution of relaxation times whose polydispersity increases with decreasing temperature. The divergence of the longest relaxation time occurs at the freezing temperature T f ∼ 198 K, which indicates the coexistence of relaxor and ferroelectric phases below T f in this system.

ChemInform, Aug 22, 2010

ABSTRACT Reaction of anodically generated thiocyanogen (NaSCN, LiClO4, MeCN, Pt, 0.9V vs SCE) wit... more ABSTRACT Reaction of anodically generated thiocyanogen (NaSCN, LiClO4, MeCN, Pt, 0.9V vs SCE) with 3-alkylsubstituted indoles results preferentially in isothiocyanation at the indole 2-position rather than in the expected thiocyanation.

ChemInform, Aug 20, 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In this work, a new method for Cu(In,Ga)Se2 thin film growth has been tested, which is different ... more In this work, a new method for Cu(In,Ga)Se2 thin film growth has been tested, which is different from the common co-evaporation and sputtering processes. The purpose of the deposition method proposed is to find a solution that combines the advantages of the sputtering and evaporation solutions for a scalable process to an industrial level. The system object of the paper allows to realize an indirect deposition of the film by sputtering to the substrate. In particular, metal precursors, with the desired ratio, are initially deposited in an area characterized by inert atmosphere, without vapors of selenium, on one or more cylindrical bodies used for the transfer. When the material deposited on the cylindrical bodies is located - as a result of the movement of rotation of the latter - in front of the substrate, where a Se atmosphere is present, it is evaporated by means of localized heating. At the moment, with the new procedure an efficiency of 14.8% has been reached on glass.

Radiation Effects and Defects in Solids, 2010

... a , Dimitri Batani a * , Yas Al Hadithi a , Rashida Jafer a , Luca Antonelli a , Bruno Vodopi... more ... a , Dimitri Batani a * , Yas Al Hadithi a , Rashida Jafer a , Luca Antonelli a , Bruno Vodopivec a , Marialuisa Vitobello b & Munawar Iqbal c pages 501-508. ... in 1986 11. Adrian, FJ, Bohandy, J., Kim, BF, Jette, AN and Thompson, P. 1987. J. Vac. Sci. Technol. B , 5: 1490–1494. ...

Physical Review B, 2009

We have identified, in erbium-doped silica with SnO 2 nanocrystals, excitation-diffusion processe... more We have identified, in erbium-doped silica with SnO 2 nanocrystals, excitation-diffusion processes restricted to the single nanocrystal. Time-resolved measurements of erbium infrared luminescence excited by energy transfer via nanocrystal excitation, together with the identification and quantification of the nanophase-related Er 3+ variety by its electron paramagnetic resonance, have allowed us to analyze the dependence of the excitation decay rate on the number of ions per nanoparticle and to reveal the effects of the discrete spatial domain composed by nanocrystals. Finally, a nonlinear relation is derived to describe the effects of Förster energy transfer in disconnected nanosystems.

The Journal of Organic Chemistry, 1997

Palinavir is a potent peptidomimetic-based HIV protease inhibitor. We have developed a highly con... more Palinavir is a potent peptidomimetic-based HIV protease inhibitor. We have developed a highly convergent and stereoselective synthesis which is amenable to the preparation of multikilogram quantities of this compound. The synthetic sequence proceeds in 24 distinct ...

Journal of Non-Crystalline Solids, 2009

Photoluminescence in fluorine-modified Sn-doped silica has been analyzed by means of synchrotron ... more Photoluminescence in fluorine-modified Sn-doped silica has been analyzed by means of synchrotron radiation in the UV and vacuum-UV, from 120 to 330 nm, looking at the optical activity of oxygen-deficient-centers ODC(II) in Sn-substituted cationic sites. The comparison between F-modified Sn-doped samples and previous data on F-free Sn-doped material evidences differences in the intensity of the 3.2 eV emission band excited at 3.7 eV, and in the thermal dependence of the intensity of this emission excited via intersystem crossing. The role of fluorine in modifying the optical activity of ODC(II) and in the SnO 2 clustering is discussed, showing that an efficient excitation transfer may be activated from SnO 2 to the Sn-variant of ODC(II).

CuInSe2-based solar cells showed long-term stability and the highest conversion efficiencies amon... more CuInSe2-based solar cells showed long-term stability and the highest conversion efficiencies among thin film solar cells, overcoming 20%. The optoelectronic properties of the absorber layers and interfaces are strongly dependent upon the deposition method and strictly related to the solar cell efficiency. In this work, an alternative approach for CIGS thin film growth has been developed and tested. Such approach consists of sputtering deposition of the metal elements combined with selenium co-evaporation, which allows deposition time of the CIGS layer lower than 30 min, matching industrial application requirements. The relationships between the growth parameters of such hybrid sputtering/evaporation method and the chemical-physical properties of the CIGS films have been studied. The CIGS cell performances have been monitored by External Quantum Efficiency measurements and I-V measurements. Test solar cells of 0.5 cm2 have shown an efficiency of 14 % on glass substrates.

Annali di chimica, 2001

The possibility of oxidizing at a PbO2 anode the phenols and polyphenols, present in the olive oi... more The possibility of oxidizing at a PbO2 anode the phenols and polyphenols, present in the olive oil mill wastewater, has been studied as a pretreatment for the submission of such wastewater to the traditional biological treatments. The results obtained operating at current densities ranging 500 to 2000 A/m2 show that it is possible to reduce the concentration of the phenolic components, which interfere with the biological treatments, down to low values without decreasing too much the total organic content of the wastewater.

Biochemistry Usa, 1999

The polymerization of hemoglobin-derived ferric-protoporphyrin IX [Fe(III)PPIX] to inert hemozoin... more The polymerization of hemoglobin-derived ferric-protoporphyrin IX [Fe(III)PPIX] to inert hemozoin (malaria pigment) is a crucial and unique process for intraerythrocytic plasmodia to prevent heme toxicity and thus a good target for new antimalarials. Quinoline drugs, i.e., chloroquine, and non-iron porphyrins have been shown to block polymerization by forming electronic pi-pi interactions with heme monomers. Here, we report the identification of ferrous-protoporphyrin IX [Fe(II)PPIX] as a novel endogenous anti-malarial. Fe(II)PPIX molecules, released from the proteolysis of hemoglobin, are first oxidized and then polymerized to hemozoin. We obtained Fe(II)PPIX on preparative scale by electrochemical reduction of Fe(III)PPIX, and the reaction was monitored by cyclic voltammetry. Polymerization assays at acidic pH were conducted with the resulting Fe(II)PPIX using a spectrophotometric microassay of heme polymerization adapted to anaerobic conditions and the products characterized by infrared spectroscopy. Fe(II)PPIX (a) did not polymerize and (b) produced a dose-dependent inhibition of Fe(III)PPIX polymerization (IC(50) = 0.4 molar equiv). Moreover, Fe(II)PPIX produced by chemical reduction with thiol-containing compounds gave similar results: a dose-dependent inhibition of heme polymerization was observed using either L-cysteine, N-acetylcysteine, or DL-homocysteine, but not with L-cystine. Cyclic voltammetry confirmed that the inhibition of heme polymerization was due to the Fe(II)PPIX molecules generated by the thiol-mediated reduction of Fe(III)PPIX. These results point to Fe(II)PPIX as a potential endogenous antimalarial and to Fe(III)PPIX reduction as a potential new pharmacological target.

... THIOCYANATION OF 3ALKYLOOLFS: AN UNEXPECTEDLY EASY ACCESS TO 2ISOTHIOCYANO DERIVATIVES Giovan... more ... THIOCYANATION OF 3ALKYLOOLFS: AN UNEXPECTEDLY EASY ACCESS TO 2ISOTHIOCYANO DERIVATIVES Giovanni PAUMISANO,*' Elisabetta BRENNA, Bruno DANI.I ... been proposed as steps in rearrangement reactions, see : Battye, PJ.; Jones, DW; Tucker, ...

ABSTRACT The interaction of 40 ps pulse duration laser emitting at 532 nm wavelength with human d... more ABSTRACT The interaction of 40 ps pulse duration laser emitting at 532 nm wavelength with human dental tissue (enamel, dentin, and dentin–enamel junction) has been investigated. The crater profile and the surface morphology have been studied by using a confocal auto-fluorescence microscope (working in reflection mode) and a scanning electron microscope. Crater profile and crater morphology were studied after applying consecutive laser pulses and it was found that the ablation depth increases with the number of consecutive pulses, leaving the crater diameter unchanged. We found that the thermal damage is reduced by using short duration laser pulses, which implies an increased retention of restorative material. We observe carbonization of the irradiated samples, which does not imply changes in the chemical composition. Finally, the use of 40 ps pulse duration laser may become a state of art in conservative dentistry.

Tetrahedron Letters, 1992

ABSTRACT Reaction of anodically generated “halonium” species (Lix or Bu4NX, LiClO4, MeCN, Pt/Pt; ... more ABSTRACT Reaction of anodically generated “halonium” species (Lix or Bu4NX, LiClO4, MeCN, Pt/Pt; I2, LiClO4, MeCN ) with pyrimidine bases and their nucleosides leads to 5-halo compounds in good yields

Journal of the European Ceramic Society, 2007

ABSTRACT

European Journal of Mineralogy, 2012

ABSTRACT The present work reports on the investigation of oxidation states, local symmetry, and o... more ABSTRACT The present work reports on the investigation of oxidation states, local symmetry, and optical properties of manganese and iron species in natural cordierite (Mg, Fe)2Al4Si5O18, by means of energy-dispersive X-ray fluorescence, electron paramagnetic resonance (EPR), photoluminescence (PL) and optical absorption techniques. In particular, specific EPR characteristics show the presence of distinct Mn2+ octahedral sites in the crystal lattice, and a small amount of Mn4+ ions in tetrahedral sites. The absence of EPR signal ascribable to Mn4+ in octahedral sites turns out to be consistent with the lack of narrow PL lines from d 3 ions in octahedral crystal field (CF). Evidence of Mn3+ in octahedral sites is instead found in steady-state and time-resolved PL measurements. EPR spectra give further details on iron site occupancy, showing the occurrence of Fe3+ ions in octahedral sites. Characteristics ascribable to all the identified metal species have been found in the optical absorption spectrum or in the PL excitation spectrum, as arising from the expected CF transitions of Fe2+, Fe3+, Mn2+, Mn3+, and Mn4+ ions. Interestingly, the results show a polarization-dependent correlation between the manganese luminescence and the pleochroic absorption band at about 17,000 cm−1. This result reveals a pleochroic contribution from the Mn3+ spin-allowed 5E→5T2 transition under the visible pleochroic band attributed to Fe2+(oct)→Fe3+(tet) transitions.