Two analytical methods previously developed by our groups were employed to estimate the antioxida... more Two analytical methods previously developed by our groups were employed to estimate the antioxidant capacity of commercial fruit juices. The electrochemical method, which measures the scavenging activity of antioxidants towards OH radicals generated by both hydrogen peroxide photolysis and Fenton’s reaction, is based on the recovery of the cyclic voltametric response of the redox probe Ru(NH3)63+ at a Glassy Carbon electrode modified with a thin film of an insulating polyphenol, in the presence of compounds with antioxidant properties. The values of the antioxidant capacity of the fruit juices are expressed as vitamin C equivalents/L. The chromatographic method is based on the generation of OH radicals via Fenton’s reaction in order to test the inhibition of their formation in the presence of antioxidant compounds by monitoring salicylate aromatic hydroxylation derivatives as markers of •OH production, by means of HPLC coupled to coulometric detection. The results are expressed as t...
Prussian Blue analogues (PBAs) are a promising class of electrode active materials for batteries.... more Prussian Blue analogues (PBAs) are a promising class of electrode active materials for batteries. Among them, copper nitroprusside, Cu[Fe(CN)5NO], has recently been investigated for its peculiar redox system, which also involves the nitrosyl ligand as a non-innocent ligand, in addition to the electroactivity of the metal sites, Cu and Fe. This paper studies the dynamics of the electrode, employing surface sensitive X-ray Photoelectron spectroscopy (XPS) and bulk sensitive X-ray absorption spectroscopy (XAS) techniques. XPS provided chemical information on the layers formed on electrode surfaces following the self-discharge process of the cathode material in the presence of the electrolyte. These layers consist mainly of electrolyte degradation products, such as LiF, LixPOyFz and LixPFy. Moreover, as evidenced by XAS and XPS, reduction at both metal sites takes place in the bulk and in the surface of the material, clearly evidencing that a self-discharge process is occurring. We obse...
The relationship between patient sex and the effectiveness of peginterferon alpha-2a and ribaviri... more The relationship between patient sex and the effectiveness of peginterferon alpha-2a and ribavirin treatment in chronic hepatitis C (CHC) patients remains unclear. The aim of this study was to investigate the impact of sex on virologic responses rates in genotype 1 CHC patients. Methods: A matched retrospective cohort study of 630 genotype 1 patients treated with peginterferon and ribavirin derived from our hospital database was conducted. These patients were divided into three groups according to age: patients aged <40 years (n = 200), patients aged 40-50 years (n = 210), and patients aged 51-60 years (n = 220). The rate of patients receiving !80% of the planned drug dose and virologic response rates were compared between males and females in the three groups. Factors influencing the sustained virologic response (SVR) were studied by multivariate analysis. Results: In patients aged 51-60 years, the rate of female patients receiving !80% of the planned ribavirin dose was significantly lower than that of males (42.7%, 47/110 vs. 61.8%, 68/110; Chi-square = 8.035, p = 0.005). In patients aged <40 years, the SVR rate of females was significantly higher than that of males (75%, 75/100 vs. 54%, 54/100; Chi-square = 9.630, p = 0.002); in patients aged 40-50 years, there was no significant difference in the SVR rate between males and females (50.5%, 53/105 vs. 54.3%, 57/105; Chisquare = 0.305, p = 0.580); in patients aged 51-60 years, the SVR rate of females was significantly lower than that of males (33.6%, 37/110 vs. 48.2%, 53/110; Chi-square = 4.814, p = 0.028). In multivariate logistic regression analysis, the independent factors associated with SVR in patients aged 51-60 years were sex (p = 0.013), !80% of the planned ribavirin dose (p = 0.008), and the presence of a rapid virologic response (p = 0.001). Conclusions: In the group of patients aged <40 years, the SVR rate of females was higher than that of males; in the group of patients aged 40-50 years, females and males shared similar SVR rates; in the group of patients aged 51-60 years, the SVR rate of females was lower than that of males.
A novel and reproducible protocol allows the electro-synthesis of LDHs for electro-catalytic appl... more A novel and reproducible protocol allows the electro-synthesis of LDHs for electro-catalytic applications.
Journal of Pharmaceutical and Biomedical Analysis, 2017
Goji berries and derived products represent a relevant source of micronutrients, most of which ar... more Goji berries and derived products represent a relevant source of micronutrients, most of which are natural antioxidants and contribute to the high nutritional quality of these fruits. Three brands of dried goji berries have been analysed by a multidisciplinary approach to get an insight into both their content of selected antioxidants and their antioxidant capacity (AC). The former goal has been achieved by developing a liquid chromatographic method coupled to mass spectrometry and combined to a fast solid phase extraction. Several significant representative antioxidant compounds belonging to the following classes: flavonoids, flavan-3-ols, phenolic acids, amino acids and derivatives, and carotenoids have been taken into account. Quercetin and rutin were found to be the predominant flavonoids; chlorogenic acid was the most abundant phenolic acid and zeaxanthin was the major carotenoid. The AC of the goji berries has been evaluated by four analytical methods in order to estimate the contributions of different reactions involved in radicals scavenging. In particular, AC has been determined using 3 standardised methods (DPPH, ABTS, ORAC) and a recently proposed electrochemical method, which measures the scavenging activity of antioxidants towards OH radicals generated both by hydrogen peroxide photolysis and the Fenton reaction. The results obtained from chemical composition and antioxidant capacity assays confirm the high nutritional and commercial value of goji berries and highlight that the three brands do not exhibit significant differences.
This paper describes the electrosynthesis and characterization in alkaline solutions of two layer... more This paper describes the electrosynthesis and characterization in alkaline solutions of two layered double hydroxides (LDHs) containing Co as divalent cation and Al or Fe as trivalent one on Pt supports. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments demonstrated a capacitive behaviour. LDHs containing Al 3+ or Fe 3+ displayed different responses, highlighting a key role of the trivalent metal. High specific capacitances calculated from charge-discharge experiments at a current density of 1 A g − 1 , were displayed by the two materials and resulted 854 and 869 F g − 1 for the Al or Fe containing LDH, respectively. The long-term cycling capability was also investigated giving satisfactory results. The presence of Fe improves the performance of the LDH as pseudocapacitor, especially to achieve better performances in terms of energy and power densities. In view of the development of low cost supercapacitors preliminary tests aimed to deposit Co based LDHs on a large area graphite substrate were also successfully carried out.
Ni-based LDHs for methanol direct fuel cells: the presence of Fe in the LDH structure enhances Ni... more Ni-based LDHs for methanol direct fuel cells: the presence of Fe in the LDH structure enhances Ni activity.
A combined X-ray absorption near edge structure (XANES) and extended X-ray absorption fine struct... more A combined X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methodology is here presented on a series of partially and fully reduced Au(III) samples. This allows monitoring the relative fraction of Au(III) and Au(0) in the studied samples, displaying a consistent and independent outcome. The strategy followed is based, for the first time, on two structural models that can be fitted simultaneously, and it evaluates the correlation among strongly correlated parameters such as coordination number and the Debye-Waller factor. The results of the present EXAFS and XANES approach can be extended to studies based on X-ray absorption spectroscopy experiments for the in situ monitoring of the formation of gold nanoclusters.
ABSTRACT A heterostructure based on gold nanoparticles (AuNPs) and NiAl layered double hydroxide ... more ABSTRACT A heterostructure based on gold nanoparticles (AuNPs) and NiAl layered double hydroxide (LDH) was prepared by one-step electrosynthesis, directly onto the electrode surface. The resulting material (AuNPs−NiAl LDH) was characterized by SEM, TEM, UV−vis, XRD, EXAFS, and XANES spectroscopy and by electrochemical techniques. The deposition process of the heterostructure on the Pt electrode was investigated by the electrochemical quartz crystal microbalance (EQCM). The electrocatalytic behavior of AuNPs−NiAl LDH toward the oxidation of methanol in basic media was compared with those of individual AuNPs and NiAl LDH, and an enhancement of the catalytic efficiency over a wide methanol concentration range was pointed out.
The product obtained by the intercalation of hexacyanoferrate(III) inside a Ni, Al hydrotalcite-l... more The product obtained by the intercalation of hexacyanoferrate(III) inside a Ni, Al hydrotalcite-like compound (Htlc) has been characterized using XRD, FT-IR, Raman, and XAS spectroscopy. The intercalation was carried out by anionic exchange of the originally existing chloride ions. The combined use of those techniques gave more insight on the insertion chemistry of Htlcs. Extended X-ray absorption fine structure spectra of the intercalated Htlc demonstrated that the native structure was stable during the iron complex insertion, whereas the exchange process occurred with a partial reduction of hexacyanoferrate(III). Both Raman and FT-IR spectroscopy pointed out the concomitant formation of K 2 NiFe II (CN) 6 and KNiFe III (CN) 6. The effect of aging on the intercalated product is also addressed.
The intercalation of hexacyanoferrate(II) ions inside the interlayer of a Ni,Al hydrotalcite has ... more The intercalation of hexacyanoferrate(II) ions inside the interlayer of a Ni,Al hydrotalcite has been carried out by anionic exchange of the originally existing chloride ions. The best exchange reaction conditions have been established in order to use the intercalated hydrotalcite as a microreactor to synthesise the compound Ni 2 II Fe II (CN) 6 , i.e., a mixed hexacyanoferrate not containing structural potassium. All the samples have been characterised by elemental chemical analysis, powder X-ray diffraction, FTIR and X-ray absorption spectroscopies and cyclic voltammetry. It has been found that, after destroying the intercalated structure by keeping it in contact with a Ni 2 + solution, the desired compound Ni 2 II Fe II (CN) 6 is not obtained, since the Fe(CN) 6 4 À ion is not exchanged as such but as the ion pair with potassium. Moreover, it has been demonstrated by X-ray absorption spectroscopy that no partial oxidation of Fe(CN) 6 4 À occurs during the intercalation inside the hydrotalcite structure.
This work describes a new one-step method for the preparation of AuNP/LDH nanocomposites via the ... more This work describes a new one-step method for the preparation of AuNP/LDH nanocomposites via the polyol route. The novelty of this facile, simple synthesis is the absence of additional reactants such as reductive agents or stabilizer, which gives the possibility to obtain phase-pure systems free of undesiderable effect. The AuNP formation is confirmed by SEM, TEM, PXRD, and XAS; moreover, the electrochemical characterization is also reported. The electrocatalytic behavior of AuNP/ LDH nanocomposites has been investigated with respect to the oxidation of methanol in basic media and compared with that of pristine NiAl-Ac. The 4-fold highest catalytic efficiency observed with AuNP/LDH nanocomposites suggests the presence of a synergic effect between Ni and AuNP sites. The combination of these experimental findings with the low-cost synthesis procedure paves the way for the exploitation of the presented nanocomposites materials as catalysts for methanol fuel cells.
Two analytical methods previously developed by our groups were employed to estimate the antioxida... more Two analytical methods previously developed by our groups were employed to estimate the antioxidant capacity of commercial fruit juices. The electrochemical method, which measures the scavenging activity of antioxidants towards OH radicals generated by both hydrogen peroxide photolysis and Fenton’s reaction, is based on the recovery of the cyclic voltametric response of the redox probe Ru(NH3)63+ at a Glassy Carbon electrode modified with a thin film of an insulating polyphenol, in the presence of compounds with antioxidant properties. The values of the antioxidant capacity of the fruit juices are expressed as vitamin C equivalents/L. The chromatographic method is based on the generation of OH radicals via Fenton’s reaction in order to test the inhibition of their formation in the presence of antioxidant compounds by monitoring salicylate aromatic hydroxylation derivatives as markers of •OH production, by means of HPLC coupled to coulometric detection. The results are expressed as t...
Prussian Blue analogues (PBAs) are a promising class of electrode active materials for batteries.... more Prussian Blue analogues (PBAs) are a promising class of electrode active materials for batteries. Among them, copper nitroprusside, Cu[Fe(CN)5NO], has recently been investigated for its peculiar redox system, which also involves the nitrosyl ligand as a non-innocent ligand, in addition to the electroactivity of the metal sites, Cu and Fe. This paper studies the dynamics of the electrode, employing surface sensitive X-ray Photoelectron spectroscopy (XPS) and bulk sensitive X-ray absorption spectroscopy (XAS) techniques. XPS provided chemical information on the layers formed on electrode surfaces following the self-discharge process of the cathode material in the presence of the electrolyte. These layers consist mainly of electrolyte degradation products, such as LiF, LixPOyFz and LixPFy. Moreover, as evidenced by XAS and XPS, reduction at both metal sites takes place in the bulk and in the surface of the material, clearly evidencing that a self-discharge process is occurring. We obse...
The relationship between patient sex and the effectiveness of peginterferon alpha-2a and ribaviri... more The relationship between patient sex and the effectiveness of peginterferon alpha-2a and ribavirin treatment in chronic hepatitis C (CHC) patients remains unclear. The aim of this study was to investigate the impact of sex on virologic responses rates in genotype 1 CHC patients. Methods: A matched retrospective cohort study of 630 genotype 1 patients treated with peginterferon and ribavirin derived from our hospital database was conducted. These patients were divided into three groups according to age: patients aged <40 years (n = 200), patients aged 40-50 years (n = 210), and patients aged 51-60 years (n = 220). The rate of patients receiving !80% of the planned drug dose and virologic response rates were compared between males and females in the three groups. Factors influencing the sustained virologic response (SVR) were studied by multivariate analysis. Results: In patients aged 51-60 years, the rate of female patients receiving !80% of the planned ribavirin dose was significantly lower than that of males (42.7%, 47/110 vs. 61.8%, 68/110; Chi-square = 8.035, p = 0.005). In patients aged <40 years, the SVR rate of females was significantly higher than that of males (75%, 75/100 vs. 54%, 54/100; Chi-square = 9.630, p = 0.002); in patients aged 40-50 years, there was no significant difference in the SVR rate between males and females (50.5%, 53/105 vs. 54.3%, 57/105; Chisquare = 0.305, p = 0.580); in patients aged 51-60 years, the SVR rate of females was significantly lower than that of males (33.6%, 37/110 vs. 48.2%, 53/110; Chi-square = 4.814, p = 0.028). In multivariate logistic regression analysis, the independent factors associated with SVR in patients aged 51-60 years were sex (p = 0.013), !80% of the planned ribavirin dose (p = 0.008), and the presence of a rapid virologic response (p = 0.001). Conclusions: In the group of patients aged <40 years, the SVR rate of females was higher than that of males; in the group of patients aged 40-50 years, females and males shared similar SVR rates; in the group of patients aged 51-60 years, the SVR rate of females was lower than that of males.
A novel and reproducible protocol allows the electro-synthesis of LDHs for electro-catalytic appl... more A novel and reproducible protocol allows the electro-synthesis of LDHs for electro-catalytic applications.
Journal of Pharmaceutical and Biomedical Analysis, 2017
Goji berries and derived products represent a relevant source of micronutrients, most of which ar... more Goji berries and derived products represent a relevant source of micronutrients, most of which are natural antioxidants and contribute to the high nutritional quality of these fruits. Three brands of dried goji berries have been analysed by a multidisciplinary approach to get an insight into both their content of selected antioxidants and their antioxidant capacity (AC). The former goal has been achieved by developing a liquid chromatographic method coupled to mass spectrometry and combined to a fast solid phase extraction. Several significant representative antioxidant compounds belonging to the following classes: flavonoids, flavan-3-ols, phenolic acids, amino acids and derivatives, and carotenoids have been taken into account. Quercetin and rutin were found to be the predominant flavonoids; chlorogenic acid was the most abundant phenolic acid and zeaxanthin was the major carotenoid. The AC of the goji berries has been evaluated by four analytical methods in order to estimate the contributions of different reactions involved in radicals scavenging. In particular, AC has been determined using 3 standardised methods (DPPH, ABTS, ORAC) and a recently proposed electrochemical method, which measures the scavenging activity of antioxidants towards OH radicals generated both by hydrogen peroxide photolysis and the Fenton reaction. The results obtained from chemical composition and antioxidant capacity assays confirm the high nutritional and commercial value of goji berries and highlight that the three brands do not exhibit significant differences.
This paper describes the electrosynthesis and characterization in alkaline solutions of two layer... more This paper describes the electrosynthesis and characterization in alkaline solutions of two layered double hydroxides (LDHs) containing Co as divalent cation and Al or Fe as trivalent one on Pt supports. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments demonstrated a capacitive behaviour. LDHs containing Al 3+ or Fe 3+ displayed different responses, highlighting a key role of the trivalent metal. High specific capacitances calculated from charge-discharge experiments at a current density of 1 A g − 1 , were displayed by the two materials and resulted 854 and 869 F g − 1 for the Al or Fe containing LDH, respectively. The long-term cycling capability was also investigated giving satisfactory results. The presence of Fe improves the performance of the LDH as pseudocapacitor, especially to achieve better performances in terms of energy and power densities. In view of the development of low cost supercapacitors preliminary tests aimed to deposit Co based LDHs on a large area graphite substrate were also successfully carried out.
Ni-based LDHs for methanol direct fuel cells: the presence of Fe in the LDH structure enhances Ni... more Ni-based LDHs for methanol direct fuel cells: the presence of Fe in the LDH structure enhances Ni activity.
A combined X-ray absorption near edge structure (XANES) and extended X-ray absorption fine struct... more A combined X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methodology is here presented on a series of partially and fully reduced Au(III) samples. This allows monitoring the relative fraction of Au(III) and Au(0) in the studied samples, displaying a consistent and independent outcome. The strategy followed is based, for the first time, on two structural models that can be fitted simultaneously, and it evaluates the correlation among strongly correlated parameters such as coordination number and the Debye-Waller factor. The results of the present EXAFS and XANES approach can be extended to studies based on X-ray absorption spectroscopy experiments for the in situ monitoring of the formation of gold nanoclusters.
ABSTRACT A heterostructure based on gold nanoparticles (AuNPs) and NiAl layered double hydroxide ... more ABSTRACT A heterostructure based on gold nanoparticles (AuNPs) and NiAl layered double hydroxide (LDH) was prepared by one-step electrosynthesis, directly onto the electrode surface. The resulting material (AuNPs−NiAl LDH) was characterized by SEM, TEM, UV−vis, XRD, EXAFS, and XANES spectroscopy and by electrochemical techniques. The deposition process of the heterostructure on the Pt electrode was investigated by the electrochemical quartz crystal microbalance (EQCM). The electrocatalytic behavior of AuNPs−NiAl LDH toward the oxidation of methanol in basic media was compared with those of individual AuNPs and NiAl LDH, and an enhancement of the catalytic efficiency over a wide methanol concentration range was pointed out.
The product obtained by the intercalation of hexacyanoferrate(III) inside a Ni, Al hydrotalcite-l... more The product obtained by the intercalation of hexacyanoferrate(III) inside a Ni, Al hydrotalcite-like compound (Htlc) has been characterized using XRD, FT-IR, Raman, and XAS spectroscopy. The intercalation was carried out by anionic exchange of the originally existing chloride ions. The combined use of those techniques gave more insight on the insertion chemistry of Htlcs. Extended X-ray absorption fine structure spectra of the intercalated Htlc demonstrated that the native structure was stable during the iron complex insertion, whereas the exchange process occurred with a partial reduction of hexacyanoferrate(III). Both Raman and FT-IR spectroscopy pointed out the concomitant formation of K 2 NiFe II (CN) 6 and KNiFe III (CN) 6. The effect of aging on the intercalated product is also addressed.
The intercalation of hexacyanoferrate(II) ions inside the interlayer of a Ni,Al hydrotalcite has ... more The intercalation of hexacyanoferrate(II) ions inside the interlayer of a Ni,Al hydrotalcite has been carried out by anionic exchange of the originally existing chloride ions. The best exchange reaction conditions have been established in order to use the intercalated hydrotalcite as a microreactor to synthesise the compound Ni 2 II Fe II (CN) 6 , i.e., a mixed hexacyanoferrate not containing structural potassium. All the samples have been characterised by elemental chemical analysis, powder X-ray diffraction, FTIR and X-ray absorption spectroscopies and cyclic voltammetry. It has been found that, after destroying the intercalated structure by keeping it in contact with a Ni 2 + solution, the desired compound Ni 2 II Fe II (CN) 6 is not obtained, since the Fe(CN) 6 4 À ion is not exchanged as such but as the ion pair with potassium. Moreover, it has been demonstrated by X-ray absorption spectroscopy that no partial oxidation of Fe(CN) 6 4 À occurs during the intercalation inside the hydrotalcite structure.
This work describes a new one-step method for the preparation of AuNP/LDH nanocomposites via the ... more This work describes a new one-step method for the preparation of AuNP/LDH nanocomposites via the polyol route. The novelty of this facile, simple synthesis is the absence of additional reactants such as reductive agents or stabilizer, which gives the possibility to obtain phase-pure systems free of undesiderable effect. The AuNP formation is confirmed by SEM, TEM, PXRD, and XAS; moreover, the electrochemical characterization is also reported. The electrocatalytic behavior of AuNP/ LDH nanocomposites has been investigated with respect to the oxidation of methanol in basic media and compared with that of pristine NiAl-Ac. The 4-fold highest catalytic efficiency observed with AuNP/LDH nanocomposites suggests the presence of a synergic effect between Ni and AuNP sites. The combination of these experimental findings with the low-cost synthesis procedure paves the way for the exploitation of the presented nanocomposites materials as catalysts for methanol fuel cells.
Uploads
Papers by Mira Tonelli