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Research Interests:
Photochemically induced viscosity changes in dilute aqueous micellar solutions of cetyltrimethylammonium bromide (CTAB) and of Triton X-100 (TRI) are brought about via the photoconversion of solubilized N-methyldiphenylamine (MDPA) to... more
Photochemically induced viscosity changes in dilute aqueous micellar solutions of cetyltrimethylammonium bromide (CTAB) and of Triton X-100 (TRI) are brought about via the photoconversion of solubilized N-methyldiphenylamine (MDPA) to N-methylcarbazole (MC). Previously, these photorheological effects were ascribed to transformations of the micellar hydration shell. New support for this rationalization was gained from ESR-spectra of various nitroxide radical spin probes measured in the respective systems. Coupling constant variations of probes associated with the micelles indicated that MDPA is solubilized near the micelle/water interface while MC is located deeper in the micellar core. Probes residing in the bulk aqueous phase were not affected by the presence of solubilizates. Only spin probes located in the aqueous phase just outside the micelle, i.e., in the hydration layer, responded to observed macroscopic viscosity changes by accordingly varying motional correlation times. — In lyotropic liquid crystalline systems phase transitions can be induced by photochemically transforming certain solubilizates, when photoeducts induce transition temperatures distinct from those induced by the photoproducts. Series of bis-thienyl-cyclopentenes (BTCPs) (capable of photocyclization) and of hydroxystilbazolium bromides (capable of cis-trans isomerizations and dimerizations) were tested as photochemically reactive solubilizates in CTAB-water (transition nematic-isotropic), AOT-glycerol, and AOT-formamide (transition lamellar-isotropic). Shifts of transition temperatures up to 10°C upon irradiating systems contamining these solubilizates were found.
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The principal aim of this study was the development of oil-in-water (o/w) microemulsions effective in the solu-bilization of acrylic copolymers. These copolymeric substances have been widely used in cultural heritage conservation since... more
The principal aim of this study was the development of oil-in-water (o/w) microemulsions effective in the solu-bilization of acrylic copolymers. These copolymeric substances have been widely used in cultural heritage conservation since 1960. They have mainly been applied as ...
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POP-Ade (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidyladenosine) is a biocompatible anionic nucleolipid with the DNA nucleoside, Adenosine, in the polar headgroup. We have studied the affinity of nucleic acids of different contour... more
POP-Ade (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidyladenosine) is a biocompatible anionic nucleolipid with the DNA nucleoside, Adenosine, in the polar headgroup. We have studied the affinity of nucleic acids of different contour length, composition and structure toward supported lipid bilayers (SLB) composed of POP-Ade mixed with the zwitterionic phospholipid POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) using quartz crystal microbalance with dissipation monitoring (QCM-D) and neutron reflectometry (NR). In order to highlight the specificity of the nucleic acid interaction, the results were compared with data obtained for SLB containing the anionic phospholipid POPG (1-palmitoyl-2-oleoyl-sn-phosphatidyl-glycerol) replacing POP-Ade. Our results demonstrate that the presence of a nucleobase headgroup provides the bilayers with the ability to bind single stranded nucleic acids in a selective fashion, according to a Watson-Crick pattern. In addition the interaction with double stranded nucleic acids was strengthened. Overall, these findings represent fundamental information for the design of biocompatible DNA vectors with DNA-RNA-based amphiphiles.
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The aim of the project is to verify a new liquid biofuel chain for heat production (proof of a concept), to determine fuel specifications for pyrolysis oil (PO) in different applications and to carry out long-term combustion tests.... more
The aim of the project is to verify a new liquid biofuel chain for heat production (proof of a concept), to determine fuel specifications for pyrolysis oil (PO) in different applications and to carry out long-term combustion tests. Scientific objectives include modification of PO composition for improved stability by hot gas filtration and production of emulsions and cleaner combustion by
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ABSTRACT
... Young So0 Kang, Piero Baglioni,+ Hugh JD McManus, and Larry Kevan* ... 1 1985,81, 1025. (7) Szajdzinska-Pietek, E.; Maldonado, D.; Kevan, L.; Jones, RR M. J. (8) Maldonado, R.; Kevan, L.; Szajdzinska-Pietek, E.; Jones, RR M. J. (9)... more
... Young So0 Kang, Piero Baglioni,+ Hugh JD McManus, and Larry Kevan* ... 1 1985,81, 1025. (7) Szajdzinska-Pietek, E.; Maldonado, D.; Kevan, L.; Jones, RR M. J. (8) Maldonado, R.; Kevan, L.; Szajdzinska-Pietek, E.; Jones, RR M. J. (9) Baglioni, P.; Kevan, L. J. Phys. Chem. ...
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ABSTRACT
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Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N',N'-tetramethylbenzidine cation radical (TMB/sup +/) in frozen mixed micelles of dodecyltrimethylammonium chloride... more
Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N',N'-tetramethylbenzidine cation radical (TMB/sup +/) in frozen mixed micelles of dodecyltrimethylammonium chloride (DTAC) and sodium dodecyl sulfate (SDS) have been studied as a function of the mixed micelle composition. ESEM effects due to TMB/sup +/ interactions with deuterium in DâO show a decrease of the TMB/sup
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ABSTRACT Electron spin resonance (ESR) spectroscopy is used to detect the photoreduction yield of alkylmethylviologens (AV{sup 2+}) in rapidly frozen dioctadecyldimethylammonium chloride (DODAC) vesicles containing concentrations of... more
ABSTRACT Electron spin resonance (ESR) spectroscopy is used to detect the photoreduction yield of alkylmethylviologens (AV{sup 2+}) in rapidly frozen dioctadecyldimethylammonium chloride (DODAC) vesicles containing concentrations of α-tocopherol (major component of vitamin E) from 0 to 23 mol %. The observed radicals are alkylmethylviologen cation radicals (AV{sup +}) from photoirradiated AV{sup 2+} in DODAC vesicles without α-tocopherol. For 1-3 mol % α-tocopherol, the major radical is AV{sup +} and the minor radical is a neutral free radical of α-tocopherol (EO) which is formed by photoinduced conversion from the α-tocopherol cation radical (EH{sup +}) with DODAC vesicles acting as proton scavengers. The total ESR intensity increases with an increase of the alkyl chain length of AV{sup 2+}. The AV{sup +} intensity increases slightly with increasing α-tocopherol concentration. For over 9 mol % α-tocopherol, the major radical becomes EO, and at 17 mol % EO alone is observed. This is explained by acceleration of the photoreduction of AV{sup 2+} to AV{sup +} by electrons released from α-tocopherol and further photoreduction of AV{sup +} to AV, which is not detected by ESR spectroscopy. The photoyield for 23 mol % α-tocopherol in DODAC vesicles without AV{sup 2+} is about 2-fold more than that in hexane solution. This enhancement of photoyield suggests that DODAC may act as a proton scavenger and compartmentalize α-tocopherol to minimize back electron reaction. 26 refs., 8 figs.
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Electron spin-echo studies have been carried out for a series of x-doxylstearic acid spin probes (x-DSA, x = 5, 7, 10, 12, and 16) in frozen micellar solutions of some poly(ethylene oxide) surfactants, CââEâ, CââEâ, CâEâ, and CâEâ, and... more
Electron spin-echo studies have been carried out for a series of x-doxylstearic acid spin probes (x-DSA, x = 5, 7, 10, 12, and 16) in frozen micellar solutions of some poly(ethylene oxide) surfactants, CââEâ, CââEâ, CâEâ, and CâEâ, and in surfactants selectively deuterated along the aliphatic chain or in the poly(ethylene oxide) groups, (CD)ââEâ, CââDâ, CâDâ, and (CD)ââEâ, in DâO
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ABSTRACT
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This perspective paper provides some illustrative examples on the interplay between information gathered on planar supported lipid bilayers (SLB) and unilamellar lipid vesicles (ULV) to get an integrated description of phenomena occurring... more
This perspective paper provides some illustrative examples on the interplay between information gathered on planar supported lipid bilayers (SLB) and unilamellar lipid vesicles (ULV) to get an integrated description of phenomena occurring at the nanoscale that involve locally bilayered structures. Similarities and differences are underlined and critically compared in terms of biomimetic fidelity and instrumental accessibility to structural and dynamical parameters, focusing on some recent reports that either explicitly address this comparison or introducing some studies that separately investigate the same process in SLB and lipid vesicles. Despite the structural similarity on the nanoscale, the different topology implies radically different characterization techniques that have evolved in sectorial and separated approaches. The quest for increasing levels of compositional complexity for bilayered systems should not result in a loss of structural and dynamical control: this is the c...
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The sodium counterion (Na+) of the sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactant was exchanged with calcium Ca2+ to investigate the counterion charge effect on the structure of water in normal decane microemulsions. Ohmic... more
The sodium counterion (Na+) of the sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactant was exchanged with calcium Ca2+ to investigate the counterion charge effect on the structure of water in normal decane microemulsions. Ohmic conductivity and dielectric permittivity measurements were performed on samples at constant water to surfactant mole ratio [water]/[Ca(AOT)(2)]=26.6. Increasing the volume fraction of the dispersed phase phi, a percolation phenomenon was observed at the constant temperature of 25 degrees C. The percolation threshold was found at phi approximately 15% by Ohmic conductivity and static dielectric permittivity studied as a function of phi, and by the frequency dependence of the complex permittivity. Critical exponents typical of the static percolation mechanism (formation of bicontinuous microemulsions) were found below and above threshold. The comparison of these results obtained for the two different counterions, Ca2+ and Na+, in AOT surfactant water in no...
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Electron spin echo studies have been carried out for a series of x-doxylstearic acid (x-DSA, x = 5,7,10,12,16) and 4-octanoyl-2,2,6,6-tetramethylpiperidine-1-oxy (Câ-TEMPO) spin probes in micellar solutions of anionic sodium dodecyl... more
Electron spin echo studies have been carried out for a series of x-doxylstearic acid (x-DSA, x = 5,7,10,12,16) and 4-octanoyl-2,2,6,6-tetramethylpiperidine-1-oxy (Câ-TEMPO) spin probes in micellar solutions of anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB) in DâO and in the presence of 2 or 6 M urea or urea-dâ. Modulation effects due to the interaction of the unpaired electron with urea and water deuteriums show that urea does not affect the bent conformation of the x-DSA probe in the micelle. The analysis of the deuterium modulation depth and the Fourier transformation of the two-pulse electron spin echo spectra show that urea interacts with the surfactant polar headgroups at the micelle surface. These results support recent molecular dynamics and Monte Carlo calculations of micellar systems and are in agreement with direct interaction of urea at micellar surfaces in which it replaces some water molecules in the surface region.
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... Solutions. Effect of Urea Piero Baglioni,**+ Elisabeth Rivara-Minten,$ Luigi Dei,§ and Enzo Ferronis Department of Chemistry, University of Udine. ... 1982, 86, 3206. J Colloid interface Sci. 1986, 110, 514 Coleman, MJ J. Am. Chem.... more
... Solutions. Effect of Urea Piero Baglioni,**+ Elisabeth Rivara-Minten,$ Luigi Dei,§ and Enzo Ferronis Department of Chemistry, University of Udine. ... 1982, 86, 3206. J Colloid interface Sci. 1986, 110, 514 Coleman, MJ J. Am. Chem. Soc. 1985, 107, 784. 4726. ...
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The characteristic relaxation time τ of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level hc=0.2-0.25 and becomes more visible as... more
The characteristic relaxation time τ of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level hc=0.2-0.25 and becomes more visible as h increases. When h is lower than hc, τ only exhibits Arrhenius behavior in the measured temperature range. The activation energy of the Arrhenius behavior is insensitive to h, indicating a local-like motion. Moreover, the h dependence of the crossover temperature shows that the protein dynamic transition is not directly or solely induced by the dynamic crossover in the hydration water.
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Complex fluids based on amphiphilic formulations are emerging, particularly in the field of conservation of works of art, as effective and safe liquid media for the removal of hydrophobic polymeric coatings. The comprehension of the... more
Complex fluids based on amphiphilic formulations are emerging, particularly in the field of conservation of works of art, as effective and safe liquid media for the removal of hydrophobic polymeric coatings. The comprehension of the cleaning mechanism is key to designing tailored fluids for this purpose. However, the interaction between nanostructured fluids and hydrophobic polymer films is still poorly understood. In this study, we show how the combination of confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) provides interesting and complementary insight into this process. We focused on the interaction between an ethyl methacrylate/methyl acrylate 70:30 copolymer film deposited onto a glass surface and a water/nonionic surfactant/2-butanone (MEK) ternary system, with MEK being a good solvent and water being a nonsolvent for the polymer. Our results indicate a synergy between the organic solvent and the surfactant assemblies: MEK rapidly swells the outer layers of the polymer film allowing for the subsequent diffusion of solvent molecules, while the amphiphile decreases the interfacial energy between the polymeric coating and the liquid phase, favoring dewetting and dispersion of swollen polymer droplets in the aqueous phase. The chemical nature of the surfactant and the microstructure of the assemblies determine both the kinetics and the overall efficiency of polymer removal, as assessed by comparing the behavior of similar formulations containing an anionic surfactant (sodium dodecyl sulfate, SDS).
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Research Interests:
The solubility of some potassium salts (KF, KCl, KBr, KI, KNO(3), KClO(4), KSCN, and KSeCN) in ethylene carbonate (EC) was determined at different temperatures with an inductively coupled plasma atomic emission spectrometer. From the... more
The solubility of some potassium salts (KF, KCl, KBr, KI, KNO(3), KClO(4), KSCN, and KSeCN) in ethylene carbonate (EC) was determined at different temperatures with an inductively coupled plasma atomic emission spectrometer. From the solubility measurements, the thermodynamic parameters ΔG, ΔH, and ΔS, of solution and of solvation, were calculated. Measurements were carried out via XRD, ATR, and FTIR to determine the effect of each salt on the properties of the solvent. The open question of whether specific ion (Hofmeister) effects are restricted to hydration peculiar to water is resolved. As for water, the effects are due to solute (ion, dipolar) induced solvent structure not accounted for by electrostatic forces. Cooperative quantum mechanical forces are necessary to understand the phenomena.
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Research Interests: Engineering, Physics, Biophysics, Materials Science, Thermodynamics, and 18 moreChemistry, Inorganic Chemistry, Physical Chemistry, Water, Protein Folding, Soft Matter, Self Assembly, Nanoparticles, Nanotechnology, DNA, Microemulsion, Nanoscience, Physical sciences, Temperature, Colloids, Microemulsions, CHEMICAL SCIENCES, and Gel
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The formation of supramolecular inclusion compounds (pseudopolyrotaxanes) produced by cyclodextrins and polymers can be monitored through turbidimetry. In this paper, we studied the kinetics of the threading of linear poly(ethylene... more
The formation of supramolecular inclusion compounds (pseudopolyrotaxanes) produced by cyclodextrins and polymers can be monitored through turbidimetry. In this paper, we studied the kinetics of the threading of linear poly(ethylene glycol) chains of different molecular weights and of a four-arm star-like polymer as a function of temperature. The main thermodynamic parameters are extracted. The aggregation and precipitation of pseudopolyrotaxanes are described in terms of the Avrami-Erofe'ev model, which provides relevant information on the mechanism of these processes. SAXS and TGA experiments confirm the structure and hydration of the final products obtained from the different polymers. A new hypothesis for the interaction between pseudopolyrotaxanes that leads to aggregation and precipitation, based on the spatial dielectric anisotropy, is proposed.
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ABSTRACT We have observed a Fragile‐to‐Strong Dynamic Crossover (FSC) phenomenon of the α‐relaxation time and self‐diffusion constant in confined supercooled water. The α‐relaxation time is measured by Quasielastic Neutron Scattering... more
ABSTRACT We have observed a Fragile‐to‐Strong Dynamic Crossover (FSC) phenomenon of the α‐relaxation time and self‐diffusion constant in confined supercooled water. The α‐relaxation time is measured by Quasielastic Neutron Scattering (QENS) experiments and the self‐diffusion constant by Nuclear Magnetic Resonance (NMR) experiments. Water is confined in 1‐d geometry in cylindrical pores of nanoscale silica materials, MCM‐41‐S and in Double‐Wall Carbon Nanotubes (DWNT). The crossover phenomenon can also be observed from appearance of a Boson peak in Incoherent Inelastic Neutron Scattering experiments. We observe a pronounced violation of the Stokes‐Einstein Relation at and below the crossover temperature at ambient pressure. Upon applying pressure to the confined water, the crossover temperature is shown to track closely the Widom line emanating from the existence of a liquid‐liquid critical point in an unattainable deeply supercooled state of bulk water. Relation of the dynamic crossover phenomenon to the existence of a density minimum in supercooled confined water is discussed. Finally, we discuss a role of the FSC of the hydration water in a biopolymer that controls the biofunctionality of the biopolymer.
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Research Interests:
... Amsterdam - Prints In Belgium MONOLAYERS OF POLY(L. D, AND DL)ALAHINE AND THEIR MIXTURES WITH ARACHIDIC ACID GABRIELLA GABRIELLI. PIERO BAGLIONI and ANNA FA13BRINI Institute of Physical Chemistry. The Unibersity of Florence. ...
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Research Interests: Bioinformatics, Molecular Dynamics Simulation, Genomics, Protein Structure Prediction, Small angle X-ray and neutron scattering, and 7 moreSpectroscopy, Cancer Biology, Transcription Factors, Next generation sequencing, Biomolecular Modeling, Self assembly of Macromolecules, and Gene expression and regulation
Cleaning is one of the most important processes for the conservation of cultural heritage artifacts, but also one of the most delicate and potentially damaging to the original materials. Nowadays, aqueous cleaning is usually preferred to... more
Cleaning is one of the most important processes for the conservation of cultural heritage artifacts, but also one of the most delicate and potentially damaging to the original materials. Nowadays, aqueous cleaning is usually preferred to cleaning with organic solvents, because it is environmental friendly and less aggressive to artifact's materials. However, in some circumstances, such as cleaning paper documents, easel paintings and textiles, water-based systems can be invasive. The interaction of water with the hydrophilic support favors mechanical stresses between substrate and paint layers, which can eventually lead to paint detachment or paint leaching. Water-based detergent systems (such as micellar solutions and oil-in-water microemulsions) offer several advantages in terms of selectivity and gentle removal of hydrosoluble (e.g. grime) and hydrophobic (e.g. aged adhesive) materials. The confinement and controlled release of these water-based systems is achieved through th...
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Silver−poly(acrylate) clusters have been synthesized in water by reduction of AgNO 3 in the presence of poly(acrylates) of different molecular weights through two different methods, NaBH 4 reduction and UV exposure. The structure of the... more
Silver−poly(acrylate) clusters have been synthesized in water by reduction of AgNO 3 in the presence of poly(acrylates) of different molecular weights through two different methods, NaBH 4 reduction and UV exposure. The structure of the clusters and the effect of the synthesis parameters ...
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ABSTRACT
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ABSTRACT The translational dynamics of the hydration water in tricalcium silicate, as well as the curing kinetics of the paste, have been investigated for the first time using neutron elastic backscattering measurements. A detailed... more
ABSTRACT The translational dynamics of the hydration water in tricalcium silicate, as well as the curing kinetics of the paste, have been investigated for the first time using neutron elastic backscattering measurements. A detailed analytical model has been formulated to extract the most important features of the calcium silicate curing process. As the curing time passes, water reacts with the tricalcium silicate, forming amorphous calcium silicate hydrate and crystalline calcium hydroxide. Concurrently, the water translational dynamics slows down due to the increased confinement in the developing matrix. The time evolution of the self-diffusion constant for the hydration water shows a decrease of 1 order of magnitude after two days of curing. The presented results agree with recent molecular dynamics simulations and 1H NMR results on similar systems.
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We report an investigation of the structural properties of dilauroyl-phosphatidyl-uridine wormlike micelles by the combined use of static light scattering and small angle neutron scattering techniques. The q-range covered in the... more
We report an investigation of the structural properties of dilauroyl-phosphatidyl-uridine wormlike micelles by the combined use of static light scattering and small angle neutron scattering techniques. The q-range covered in the reciprocal space is large enough for a ...
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... 24) Berti, D., Franchi, L., Baglioni, P., Luisi, PLL Langmuir1997, 13, 3441. (25) Berti, D., Baglioni, P., Barsacchi-Bo, G.; Bonaccio, S., Luisi, PLL J. Phys. Chem. B 1998, 102, 303. ...