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Kotsidi M, Gorgolis G, Pastore Carbone MG, Anagnostopoulos G, Paterakis G, Poggi G, Manikas A, Trakakis G, Baglioni P, Galiotis C. Preventing colour fading in artworks with graphene veils. Nat Nanotechnol 2021; 16:1004-1010. [PMID: 34211165 DOI: 10.1038/s41565-021-00934-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Modern and contemporary art materials are generally prone to irreversible colour changes upon exposure to light and oxidizing agents. Graphene can be produced in thin large sheets, blocks ultraviolet light, and is impermeable to oxygen, moisture and corrosive agents; therefore, it has the potential to be used as a transparent layer for the protection of art objects in museums, during storage and transportation. Here we show that a single-layer or multilayer graphene veil, produced by chemical vapour deposition, can be deposited over artworks to protect them efficiently against colour fading, with a protection factor of up to 70%. We also show that this process is reversible since the graphene protective layer can be removed using a soft rubber eraser without causing any damage to the artwork. We have also explored a complementary contactless graphene-based route for colour protection that is based on the deposition of graphene on picture framing glass for use when the direct application of graphene is not feasible due to surface roughness or artwork fragility. Overall, the present results are a proof of concept of the potential use of graphene as an effective and removable protective advanced material to prevent colour fading in artworks.
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Affiliation(s)
- M Kotsidi
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
- Department of Chemical Engineering, University of Patras, Patras, Greece
| | - G Gorgolis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - M G Pastore Carbone
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - G Anagnostopoulos
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - G Paterakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
- Department of Chemical Engineering, University of Patras, Patras, Greece
| | - G Poggi
- CSGI & Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - A Manikas
- Department of Chemical Engineering, University of Patras, Patras, Greece
| | - G Trakakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - P Baglioni
- CSGI & Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - C Galiotis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece.
- Department of Chemical Engineering, University of Patras, Patras, Greece.
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Xu Q, Poggi G, Resta C, Baglioni M, Baglioni P. Grafted nanocellulose and alkaline nanoparticles for the strengthening and deacidification of cellulosic artworks. J Colloid Interface Sci 2020; 576:147-157. [PMID: 32416547 DOI: 10.1016/j.jcis.2020.05.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 11/17/2022]
Abstract
HYPOTHESIS Strongly degraded cellulosic artworks usually need deacidification and consolidation. Alkaline nanoparticles are known to be effective in neutralizing the acidity, while cellulose nanocrystals have the potential to be used as compatible and effective strengthening agents. EXPERIMENTS We have grafted cellulose nanocrystals with oleic acid using a 1'1-carbonyldiimidazole-mediated procedure, to increase their dispersibility in organic solvents, and synthesized Ca(OH)2 or CaCO3 nanoparticles via a solvothermal process. Grafted nanocellulose and alkaline nanoparticles were used to prepare ethanol-based "hybrids". Prior to the application, the physico-chemical properties of nanocellulose dispersions and "hybrids" were studied by rheology and small-angle X-ray scattering. FINDINGS Cellulose nanocrystals were effectively grafted and stably dispersed in ethanol. It was shown that the use of ethanol as a dispersing medium, and the addition of alkaline nanoparticles act in a synergistic way, increasing the interactions between grafted cellulose nanocrystals, leading to the formation of clusters. These dispersions are thixotropic, a behavior particularly appealing to conservation purposes, since they can be applied in the liquid state, or, when a more confined application is required, they can be applied in a gel-like state. As a result of the application, an improvement in the mechanical properties of paper and an increase of pH were obtained.
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Affiliation(s)
- Q Xu
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy
| | - G Poggi
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy.
| | - C Resta
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy
| | - M Baglioni
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy
| | - P Baglioni
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy.
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Camerini R, Poggi G, Chelazzi D, Ridi F, Giorgi R, Baglioni P. The carbonation kinetics of calcium hydroxide nanoparticles: A Boundary Nucleation and Growth description. J Colloid Interface Sci 2019; 547:370-381. [PMID: 30974252 DOI: 10.1016/j.jcis.2019.03.089] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 10/27/2022]
Abstract
HYPOTHESIS The reaction of Ca(OH)2 with CO2 to form CaCO3 (carbonation process) is of high interest for construction materials, environmental applications and art preservation. Here, the "Boundary Nucleation and Growth" model (BNGM) was adopted for the first time to consider the effect of the surface area of Ca(OH)2 nanoparticles on the carbonation kinetics. EXPERIMENTS The carbonation of commercial and laboratory-prepared particles' dispersions was monitored by Fourier Transform Infrared Spectroscopy, and the BNGM was used to analyze the data. The contributions of nucleation and growth of CaCO3 were evaluated separately. FINDINGS During carbonation the boundary regions of the Ca(OH)2 particles are densely populated with CaCO3 nuclei, and transform early with subsequent thickening of slab-like regions centered on the original boundaries. A BNGM limiting case equation was thus used to fit the kinetics, where the transformation rate decreases exponentially with time. The carbonation rate constants, activation energies, and linear growth rate were calculated. Particles with larger size and lower surface area show a decrease of the rate at which the non-nucleated grains between the boundaries transform, and an increase of the ending time of Ca(OH)2 transformation. The effect of temperature on the carbonation kinetics and on the CaCO3 polymorphs formation was evaluated.
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Affiliation(s)
- R Camerini
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - G Poggi
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - D Chelazzi
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - F Ridi
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - R Giorgi
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - P Baglioni
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
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Baglioni M, Montis C, Brandi F, Guaragnone T, Meazzini I, Baglioni P, Berti D. Dewetting acrylic polymer films with water/propylene carbonate/surfactant mixtures - implications for cultural heritage conservation. Phys Chem Chem Phys 2018; 19:23723-23732. [PMID: 28581560 DOI: 10.1039/c7cp02608k] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The removal of hydrophobic polymer films from surfaces is one of the top priorities of modern conservation science. Nanostructured fluids containing water, good solvents for polymers, either immiscible or partially miscible with water, and surfactants have been used in the last decade to achieve controlled removal. The dewetting of the polymer film is often an essential step to achieve efficient removal; however, the role of the surfactant throughout the process is yet to be fully understood. We report on the dewetting of a methacrylate/acrylate copolymer film induced by a ternary mixture of water, propylene carbonate (PC) and C9-11E6, a nonionic alcohol ethoxylate surfactant. The fluid microstructure was characterised through small angle X-ray scattering and the interactions between the film and water, water/PC and water/PC/C9-11E6, were monitored through confocal laser-scanning microscopy (CLSM) and analised both from a thermodynamic and a kinetic point of view. The presence of a surfactant is a prerequisite to induce dewetting of μm-thick films at room temperature, but it is not a thermodynamic driver. The amphiphile lowers the interfacial energy between the phases and favors the loss of adhesion of the polymer on glass, decreasing, in turn, the activation energy barrier, which can be overcome by the thermal fluctuations of polymer film stability, initiating the dewetting process.
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Affiliation(s)
- M Baglioni
- Chemistry Department & CSGI, University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino (FI), Italy.
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Scarano S, Carretti E, Dei L, Baglioni P, Minunni M. Coupling non invasive and fast sampling of proteins from work of art surfaces to surface plasmon resonance biosensing: Differential and simultaneous detection of egg components for cultural heritage diagnosis and conservation. Biosens Bioelectron 2016; 85:83-89. [PMID: 27155120 DOI: 10.1016/j.bios.2016.04.093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/27/2016] [Accepted: 04/27/2016] [Indexed: 11/26/2022]
Abstract
Despite the wide application of surface plasmon resonance (SPR) to a broad area of interests, from environment to food analysis, from drug discovery to diagnostics, its exploitation in cultural heritage conservation is still unexplored. Water-based highly viscous polymeric dispersions (HVPD) composed by partially hydrolyzed polyvinyl acetate (PVA), borax, and water, were recently developed and successfully applied for the selective removal of surface degradation patinas (i.e. protein materials, natural resins etc.) from paintings of historical and artistic interest. This approach is here coupled for the first time to a SPR biosensor to simultaneously recognize albumen, yolk, or their mixtures in HVPD extracts. Ovalbumin and immunoglobulin Y are selected as analytes for egg white and yolk recognition, respectively. The biosensor was first characterized on standard analytes within the range 0-400mgL(-1) and then on fresh and dried egg albumen and yolk down to 2·10(^4) and 1·10(^5) dilution factors, respectively. Once optimized, the biosensor was combined to the HVPD application on simulated and real art samples for the evaluation of hen egg presence in the extract, i.e. albumen, yolk, or their co-presence in the matrix. For a contemporary 'sacred icon', realized by the traditional egg tempera procedure described by Cennino Cennini, the biosensor successfully distinguished different uses of egg components for the realization of painted and gilded areas, i.e. yolk and albumen, respectively. Finally, a XVIII century italian painting whose the realization technique is unknown, was tested confirming its egg tempera-based realization technique.
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Affiliation(s)
- S Scarano
- Department of Chemistry 'Ugo Schiff' and CSGI, University of Florence, via della Lastruccia 3-13, 50019, Sesto Fiorentino, Florence, Italy.
| | - E Carretti
- Department of Chemistry 'Ugo Schiff' and CSGI, University of Florence, via della Lastruccia 3-13, 50019, Sesto Fiorentino, Florence, Italy
| | - L Dei
- Department of Chemistry 'Ugo Schiff' and CSGI, University of Florence, via della Lastruccia 3-13, 50019, Sesto Fiorentino, Florence, Italy
| | - P Baglioni
- Department of Chemistry 'Ugo Schiff' and CSGI, University of Florence, via della Lastruccia 3-13, 50019, Sesto Fiorentino, Florence, Italy.
| | - M Minunni
- Department of Chemistry 'Ugo Schiff' and CSGI, University of Florence, via della Lastruccia 3-13, 50019, Sesto Fiorentino, Florence, Italy
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Gårdebjer S, Gebäck T, Andersson T, Fratini E, Baglioni P, Bordes R, Viridén A, Nicholas M, Lorén N, Larsson A. The impact of interfaces in laminated packaging on transport of carboxylic acids. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2016.06.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Tonelli M, Martini F, Calucci L, Fratini E, Geppi M, Ridi F, Borsacchi S, Baglioni P. Structural characterization of magnesium silicate hydrate: towards the design of eco-sustainable cements. Dalton Trans 2016; 45:3294-304. [PMID: 26781557 DOI: 10.1039/c5dt03545g] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Magnesium-based cement is one of the most interesting eco-sustainable alternatives to standard cementitious binders. The reasons for the interest towards this material are twofold: (i) its production process, using magnesium silicates, brine or seawater, dramatically reduces CO2 emissions with respect to Portland cement production, and (ii) it is very well suited to applications in radioactive waste encapsulation. In spite of its potential, assessment of the structural properties of its binder phase (magnesium silicate hydrate or M-S-H) is far from complete, especially because of its amorphous character. In this work, a comprehensive structural characterization of M-S-H was obtained using a multi-technique approach, including a detailed solid-state NMR investigation and, in particular, for the first time, quantitative (29)Si solid-state NMR data. M-S-H was prepared through room-temperature hydration of highly reactive MgO and silica fume and was monitored for 28 days. The results clearly evidenced the presence in M-S-H of "chrysotile-like" and "talc-like" sub-nanometric domains, which are approximately in a 1 : 1 molar ratio after long-time hydration. Both these kinds of domains have a high degree of condensation, corresponding to the presence of a small amount of silanols in the tetrahedral sheets. The decisive improvement obtained in the knowledge of M-S-H structure paves the way for tailoring the macroscopic properties of eco-sustainable cements by means of a bottom-up approach.
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Affiliation(s)
- M Tonelli
- Department of Chemistry "Ugo Schiff" & CSGI, University of Florence, Sesto Fiorentino 50019, Florence, Italy.
| | - F Martini
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Ricerche - CNR U.O.S. di Pisa, Pisa 56124, Italy.
| | - L Calucci
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Ricerche - CNR U.O.S. di Pisa, Pisa 56124, Italy.
| | - E Fratini
- Department of Chemistry "Ugo Schiff" & CSGI, University of Florence, Sesto Fiorentino 50019, Florence, Italy.
| | - M Geppi
- Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa 56124, Italy
| | - F Ridi
- Department of Chemistry "Ugo Schiff" & CSGI, University of Florence, Sesto Fiorentino 50019, Florence, Italy.
| | - S Borsacchi
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Ricerche - CNR U.O.S. di Pisa, Pisa 56124, Italy.
| | - P Baglioni
- Department of Chemistry "Ugo Schiff" & CSGI, University of Florence, Sesto Fiorentino 50019, Florence, Italy.
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Bellissima F, Bonini M, Giorgi R, Baglioni P, Barresi G, Mastromei G, Perito B. Antibacterial activity of silver nanoparticles grafted on stone surface. Environ Sci Pollut Res Int 2014; 21:13278-13286. [PMID: 24151026 DOI: 10.1007/s11356-013-2215-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 10/02/2013] [Indexed: 06/02/2023]
Abstract
Microbial colonization has a relevant impact on the deterioration of stone materials with consequences ranging from esthetic to physical and chemical changes. Avoiding microbial growth on cultural stones therefore represents a crucial aspect for their long-term conservation. The antimicrobial properties of silver nanoparticles (AgNPs) have been extensively investigated in recent years, showing that they could be successfully applied as bactericidal coatings on surfaces of different materials. In this work, we investigated the ability of AgNPs grafted to Serena stone surfaces to inhibit bacterial viability. A silane derivative, which is commonly used for stone consolidation, and Bacillus subtilis were chosen as the grafting agent and the target bacterium, respectively. Results show that functionalized AgNPs bind to stone surface exhibiting a cluster disposition that is not affected by washing treatments. The antibacterial tests on stone samples revealed a 50 to 80 % reduction in cell viability, with the most effective AgNP concentration of 6.7 μg/cm(2). To our knowledge, this is the first report on antimicrobial activity of AgNPs applied to a stone surface. The results suggest that AgNPs could be successfully used in the inhibition of microbial colonization of stone artworks.
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Affiliation(s)
- F Bellissima
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Florence, Italy
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Baglioni M, Raudino M, Berti D, Keiderling U, Bordes R, Holmberg K, Baglioni P. Nanostructured fluids from degradable nonionic surfactants for the cleaning of works of art from polymer contaminants. Soft Matter 2014; 10:6798-6809. [PMID: 25079380 DOI: 10.1039/c4sm01084a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Nanostructured fluids containing anionic surfactants are among the best performing systems for the cleaning of works of art. Though efficient, their application may result in the formation of a precipitate, due to the combination with divalent cations that might leach out from the artifact. We propose here two new aqueous formulations based on nonionic surfactants, which are non-toxic, readily biodegradable and insensitive to the presence of divalent ions. The cleaning properties of water-nonionic surfactant-2-butanone (MEK) were assessed both on model surfaces and on a XIII century fresco that could not be cleaned using conventional methods. Structural information on nanofluids has been gathered by means of small-angle neutron scattering, dynamic light scattering and nuclear magnetic resonance with diffusion monitoring. Beside the above-mentioned advantages, these formulations turned out to be considerably more efficient in the removal of polymer coatings than those based on anionic surfactants. Our results indicate that the cleaning process most likely consists of two steps: initially, the polymer film is swollen by the MEK dissolved in the continuous domain of the nanofluid; in the second stage, surfactant aggregates come into play by promoting the removal of the polymer film with a detergency-like mechanism. The efficiency can be tuned by the composition and nature of amphiphiles and is promoted by working as close as possible to the cloud point of the formulation, where the second step proceeds at maximum rate.
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Affiliation(s)
- M Baglioni
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019, Italy.
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Carretti E, Matarrese C, Fratini E, Baglioni P, Dei L. Physicochemical characterization of partially hydrolyzed poly(vinyl acetate)-borate aqueous dispersions. Soft Matter 2014; 10:4443-4450. [PMID: 24818671 DOI: 10.1039/c4sm00355a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The dynamic and structural properties of Highly Viscous Polymeric Dispersions (HVPDs), constituted of polyvinyl alcohol obtained from the 75% hydrolysis (75PVA) of polyvinlyl acetate (PVAc) cross-linked with borate ions, were studied as a function of the 75PVA concentration at a constant ratio between the OH groups and the borate ions (OH/B(OH)4(-)). The threshold 75PVA concentration C* necessary for the formation of the three-dimensional network was determined by flow rheology. The oscillating rheology measurements were performed in the linear viscoelastic region; the relaxation spectra calculated from the frequency sweep curves showed only one peak whose width increased upon increasing the 75PVA concentration due to the broadening of the relaxation modes. The dependence of the mean relaxation time τH upon the concentration of 75PVA followed a power law expression (τH ∼ C(x) with x = 1.9) indicating that τH referred to a sticky reptation mechanism and that water was a good solvent for 75PVA as confirmed also by small angle X-rays scattering (SAXS) investigation. The HVPDs were used for the removal of grime layers from the surface of Carlo Carrà (1881-1966) paints decorating the walls of the Palazzo di Giustizia in Milan, Italy.
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Affiliation(s)
- E Carretti
- Department of Chemistry & CSGI Consortium, University of Florence, via della Lastruccia, 3 - 50019 Sesto Fiorentino, Florence, Italy.
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Banchelli M, Nappini S, Montis C, Bonini M, Canton P, Berti D, Baglioni P. Magnetic nanoparticle clusters as actuators of ssDNA release. Phys Chem Chem Phys 2014; 16:10023-31. [PMID: 24487734 DOI: 10.1039/c3cp55470h] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
One of the major areas of research in nanomedicine is the design of drug delivery systems with remotely controllable release of the drug. Despite the enormous progress in the field, this aspect still poses a challenge, especially in terms of selectivity and possible harmful interactions with biological components other than the target. We report an innovative approach for the controlled release of DNA, based on clusters of core-shell magnetic nanoparticles. The primary nanoparticles are functionalized with a single-stranded oligonucleotide, whose pairing with a half-complementary strand in solution induces clusterization. The application of a low frequency (6 KHz) alternating magnetic field induces DNA melting with the release of the single strand that induces clusterization. The possibility of steering and localizing the magnetic nanoparticles, and magnetically actuating the DNA release discloses new perspectives in the field of nucleic-acid based therapy.
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Affiliation(s)
- M Banchelli
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Florence, Italy.
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Abstract
OBJECTIVE Optimal therapeutic strategies for subclinical hyperthyroidism are undecided. Overt disease develops in a minority of cases, but the risk factors for progression remain unclear. We examined whether a baseline thyrotrophin (TSH) predicted progression to overt hyperthyroidism in asymptomatic individuals with subclinical hyperthyroidism. DESIGN, PATIENTS AND MEASUREMENTS This was a retrospective study of 323 patients with subclinical hyperthyroidism seen in our institution from 2003 to 2010 (mean age 71 years, males 26·9%, females 73·1%, mean follow-up duration 32 months, range 6-93 months). Serum TSH and free thyroxine (FT4) were documented at baseline and during follow-up. After excluding individuals with nonthyroid causes of low TSH, patients were grouped according to initial TSH as: TSH 0·10-0·39 mU/l (grade I) and TSH < 0·10 mU/l (grade II). RESULTS Only 38 patients (11·8%) developed overt hyperthyroidism with annual progression rates of 0·6-3·7%. Most patients reverted to normal thyroid status (31·6%) or remained subclinically hyperthyroid (56·7%). Progression to frank hyperthyroidism was higher in grade II than in grade I patients (20·3% vs 6·8%, P < 0·001, Chi square test). Kaplan-Meier curves showed faster progression rates in grade II than grade I (P < 0·001, log rank test). In stepwise multivariate Cox regression analysis, TSH < 0·1 mU/l was associated with overt hyperthyroidism (hazard ratio 3·4, confidence interval 1·6-7·0), whereas age, gender, FT4 and aetiological diagnosis were not associated with hyperthyroidism. CONCLUSIONS Thyrotrophin predicts overt hyperthyroidism in asymptomatic individuals with subclinical hyperthyroidism. Patients with TSH < 0·10 mU/l have a higher risk of progressing to hyperthyroidism than those with TSH 0·10-0·39 mU/l.
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Affiliation(s)
- G Das
- Department of Endocrinology and Diabetes, Prince Charles Hospital, Cwm Taf Local Health Board, Merthyr Tydfil, UK
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Das G, Baglioni P, Mallipedhi A, Okosieme O. Adrenal incidentaloma's: are lessons still to be learned? QJM 2011; 104:374-7. [PMID: 20534654 DOI: 10.1093/qjmed/hcq096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Das G, Baglioni P. Coeliac disease: does it always present with gastrointestinal symptoms? QJM 2010; 103:999-1000. [PMID: 20385568 DOI: 10.1093/qjmed/hcq046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kadiyala R, Kamath C, Baglioni P, Geen J, Okosieme OE. Can a random serum cortisol reduce the need for short synacthen tests in acute medical admissions? Ann Clin Biochem 2010; 47:378-80. [PMID: 20488874 DOI: 10.1258/acb.2010.010008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Short synacthen tests (SSTs) are frequently performed in medical inpatients with suspected adrenocortical insufficiency. The utility of a random or baseline serum cortisol in this setting is unclear. We determined random cortisol thresholds that safely preclude SSTs in acute medical admissions. METHODS We analysed SSTs in acute non-critically ill general medical patients (n = 166, median age 66, range 15-94 y; men 48%, women 52%). The SST was defined according to the 30-min cortisol as 'pass' (>550 nmol/L) or 'fail' (< or =550 nmol/L). Receiver operating characteristics (ROC) curves were generated to determine the predictive value of the basal cortisol for a failed SST. RESULTS Of 166 SSTs, a pass was seen in 127 (76.5%) tests, while 39 (23.5%) tests failed the SST. ROC curves showed that no single cut-off point of the baseline cortisol was adequately both sensitive and specific for failing the SST despite a good overall predictive value (area under curve 0.94; 95% confidence interval 0.89-0.98). A basal cortisol <420 nmol/L had 100% sensitivity and 54% specificity for failing the SST, while a basal cortisol <142 nmol/L had 100% specificity and 35% sensitivity. Restricting the SST to patients with a basal cortisol <420 nmol/L would have prevented 44% of SSTs while correctly identifying all patients who failed the SST. CONCLUSION A baseline serum cortisol may prevent unnecessary SSTs in medical inpatients with suspected adrenocortical insufficiency. However, SSTs are still indicated in patients with random cortisol <420 nmol/L, or where the suspicion of adrenal insufficiency is compelling.
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Affiliation(s)
- R Kadiyala
- Department of Endocrinology and Diabetes, Prince Charles Hospital, Cwm Taf Local Health Board, Merthyr Tydfil, Mid Glamorgan CF47 9DT, UK
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Laurati M, Gambi C, Giordano R, Baglioni P, Teixeira J. Small-Angle Neutron Scattering of Percolative Perfluoropolyether Water in Oil Microemulsions. J Phys Chem B 2010; 114:3855-62. [DOI: 10.1021/jp911278j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Laurati
- Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia Recherche et Technologie, 85 rue des Frères Perret, 69192 Saint-Fons Cedex, France, Polymers and Soft Matter Group, Centro de Fisica de Materiales, Universidad del Paìs Vasco, Paseo Manuel Lardizabal 4, 20018 Donostia/San Sebastiàn, Spain, Department of Physics and CNISM Via G. Sansone 1, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, Deptartment of Physics, University of Messina and CNISM, Salita Sperone 31, 98010 S. Agata,
| | - C.M.C. Gambi
- Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia Recherche et Technologie, 85 rue des Frères Perret, 69192 Saint-Fons Cedex, France, Polymers and Soft Matter Group, Centro de Fisica de Materiales, Universidad del Paìs Vasco, Paseo Manuel Lardizabal 4, 20018 Donostia/San Sebastiàn, Spain, Department of Physics and CNISM Via G. Sansone 1, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, Deptartment of Physics, University of Messina and CNISM, Salita Sperone 31, 98010 S. Agata,
| | - R. Giordano
- Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia Recherche et Technologie, 85 rue des Frères Perret, 69192 Saint-Fons Cedex, France, Polymers and Soft Matter Group, Centro de Fisica de Materiales, Universidad del Paìs Vasco, Paseo Manuel Lardizabal 4, 20018 Donostia/San Sebastiàn, Spain, Department of Physics and CNISM Via G. Sansone 1, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, Deptartment of Physics, University of Messina and CNISM, Salita Sperone 31, 98010 S. Agata,
| | - P. Baglioni
- Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia Recherche et Technologie, 85 rue des Frères Perret, 69192 Saint-Fons Cedex, France, Polymers and Soft Matter Group, Centro de Fisica de Materiales, Universidad del Paìs Vasco, Paseo Manuel Lardizabal 4, 20018 Donostia/San Sebastiàn, Spain, Department of Physics and CNISM Via G. Sansone 1, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, Deptartment of Physics, University of Messina and CNISM, Salita Sperone 31, 98010 S. Agata,
| | - J. Teixeira
- Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia Recherche et Technologie, 85 rue des Frères Perret, 69192 Saint-Fons Cedex, France, Polymers and Soft Matter Group, Centro de Fisica de Materiales, Universidad del Paìs Vasco, Paseo Manuel Lardizabal 4, 20018 Donostia/San Sebastiàn, Spain, Department of Physics and CNISM Via G. Sansone 1, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, Deptartment of Physics, University of Messina and CNISM, Salita Sperone 31, 98010 S. Agata,
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Chen SH, Zhang Y, Lagi M, Chong SH, Baglioni P, Mallamace F. Evidence of dynamic crossover phenomena in water and other glass-forming liquids: experiments, MD simulations and theory. J Phys Condens Matter 2009; 21:504102. [PMID: 21836213 DOI: 10.1088/0953-8984/21/50/504102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In a recent quasi-elastic neutron scattering experiment on water confined in a Portland cement paste, we find that this 3D confined water shows a dynamic crossover phenomenon at T(L) = 227 ± 5 K. The DSC heat-flow scan upon cooling and an independent measurement of specific heat at constant pressure of confined water in silica gel show a prominent peak at the same temperature. We show in this paper that this type of behavior is common to many other glassy liquids, which also show the crossover temperature in coincidence with the temperature of a small specific heat peak. We also demonstrate with MD simulations that the dynamic crossover phenomenon in confined water is an intrinsic property of bulk water, and is not due to the confinement effect. Recently, an extended version of the mode coupling theory (MCT) including the hopping effect was developed. This theory shows that, instead of a structural arrest transition at T(C) predicted by the idealized MCT, a fragile-to-strong dynamic crossover phenomenon takes place instead at T(C), confirming both the experimental and the numerical results. The coherent and incoherent α relaxation times can be scaled with the calculated viscosity, showing the same crossover phenomenon. We thus demonstrated with experiments, simulations and theory that a genuine change of dynamical behavior of both water and many glassy liquids happens at the crossover temperature T(L), which is 10-30% higher than the calorimetric glass transition temperature T(g).
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Affiliation(s)
- S H Chen
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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18
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Baglioni P, Okosieme O. Understanding what you read. West J Med 2009. [DOI: 10.1136/bmj.b3630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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19
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Baglioni P, Neto W, Kato L, Castilho L. Abstract: P942 REGULAR AEROBIC MODERATE EXERCISE IN YOUNG MALES LEADS TO A DECREASE IN CETP ACTIVITY AND PROMOTES VLDL AND LDL FAVORABLE COMPOSITION CHANGES. ATHEROSCLEROSIS SUPP 2009. [DOI: 10.1016/s1567-5688(09)71063-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Pileri S, Poggi S, Baglioni P, Montanari M, Sabattini E, Galieni P, Tazzari PL, Gobbi M, Cavo M, Falini B. Histology and immunohistology of bone marrow biopsy in multiple myeloma. Eur J Haematol Suppl 2009; 51:52-9. [PMID: 2627992 DOI: 10.1111/j.1600-0609.1989.tb01493.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
B5-fixed/paraffin-embedded Jamshidi needle biopsies from 125 multiple myeloma patients were reviewed according to both morphological and immunohistological criteria. At microscopic examination, the following parameters were evaluated: i) grade of malignancy (low = 56; intermediate = 50; high = 19); ii) growth pattern (interstitial +/- sheets/nodules = 90; nodular = 13; packed marrow = 18; sarcomatous = 4); III) histological stage (I = 64; II = 35; III = 26). Comparison of the findings in trephine biopsies and aspirates showed that in 30% of the cases the latter led to an underestimation of the tumor burden. Immunohistochemical determination of Ig easily allowed: i) differential diagnosis from exuberant reactive plasmacytosis; ii) recognition and counting of neoplastic plasma cells; iii) detection of minimal residual disease after treatment. Immunohistochemistry also confirmed phenotypic aberration of neoplastic plasma cells, showing positivity for CD45, EMA, and cytokeratins in 14%, 59%, and 25% of the cases, respectively. Furthermore, it displayed expression of the P-glycoprotein in 4/8 resistant cases. These findings underline that routinely processed Jamshidi needle biopsies can be of great value in the study of patients with multiple myeloma.
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Baglioni P. Comment on: Urinary tract infection in hospitalized elderly patients in the United Kingdom: the importance of making an accurate diagnosis in the post broad-spectrum antibiotic era. J Antimicrob Chemother 2009; 63:846; author reply 846-7. [DOI: 10.1093/jac/dkp022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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22
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Banchelli M, Betti F, Berti D, Caminati G, Bombelli FB, Brown T, Wilhelmsson LM, Nordén B, Baglioni P. Phospholipid membranes decorated by cholesterol-based oligonucleotides as soft hybrid nanostructures. J Phys Chem B 2008; 112:10942-52. [PMID: 18693696 DOI: 10.1021/jp802415t] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
DNA monomers and oligomers are currently showing great promise as building blocks for supramolecular arrays that can self-assemble in a fashion preprogrammed by the base pairing code. The design and build-up of hybrid DNA/amphiphilic self-assemblies can expand the range of possible architectures and enhance the selectivity toward a well-specified geometry. We report on the self-assembly properties in aqueous solution of a cholesteryl-tetraethylenglycol single stranded 18-mer oligonucleotide (ON 1TEG-Chol) and on its spontaneous insertion in fluid phospholipid membranes. Up to 500 units of these lipophilic ss-oligonucleotides can be incorporated in the outer leaflet of 350 A radius POPC vesicle. The insertion and hybridization with the complementary oligonucleotide are monitored through light scattering as an increase of hydrodynamic thickness, which is interpreted in terms of average distance between anchoring sites. The conformation of the ss-oligonucleotidic portion is strongly dependent on surface coverage, passing from a quasi-random coil to a more rigid configuration, as concentration increases. Interestingly, conformational details affect in a straightforward fashion the hybridization kinetics. Liposomes with single- and double-strand decorations remain stable within the experimental time window (about one week). The structure represents an example of successful and stable amphiphile/DNA supramolecular hybrid, where a DNA guest is held in a membrane by hydrophobic interactions. The lipophilic oligonucleotide under investigation is therefore a suitable building block that can effectively serve as a hydrophobic anchor in the fluid bilayer to assemble supramolecular constructs based on the DNA digital code.
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Affiliation(s)
- Martina Banchelli
- Department of Chemistry and CSGI, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy
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Gambinossi F, Lorenzelli L, Baglioni P, Caminati G. Silicon oxide surface functionalization by self-assembled nanolayers for microcantilever transducers. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2008.01.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chen SH, Mallamace F, Liu L, Liu DZ, Chu XQ, Zhang Y, Kim C, Faraone A, Mou CY, Fratini E, Baglioni P, Kolesnikov AI, Garcia-Sakai V, Tokuyama M, Oppenheim I, Nishiyama H. Dynamic Crossover Phenomenon in Confined Supercooled Water and Its Relation to the Existence of a Liquid-Liquid Critical Point in Water. ACTA ACUST UNITED AC 2008. [DOI: 10.1063/1.2897826] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Chen SH, Liu L, Chu X, Zhang Y, Fratini E, Baglioni P, Faraone A, Mamontov E. Experimental evidence of fragile-to-strong dynamic crossover in DNA hydration water. J Chem Phys 2007; 125:171103. [PMID: 17100421 DOI: 10.1063/1.2372491] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We used high-resolution quasielastic neutron scattering spectroscopy to study the single-particle dynamics of water molecules on the surface of hydrated DNA samples. Both H(2)O and D(2)O hydrated samples were measured. The contribution of scattering from DNA is subtracted out by taking the difference of the signals between the two samples. The measurement was made at a series of temperatures from 270 down to 185 K. The relaxing-cage model was used to analyze the quasielastic spectra. This allowed us to extract a Q-independent average translational relaxation time <tau(T)> of water molecules as a function of temperature. We observe clear evidence of a fragile-to-strong dynamic crossover (FSC) at T(L)=222+/-2 K by plotting log<tau(T)> versus T. The coincidence of the dynamic transition temperature T(c) of DNA, signaling the onset of anharmonic molecular motion, and the FSC temperature T(L) of the hydration water suggests that the change of mobility of the hydration water molecules across T(L) drives the dynamic transition in DNA.
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Affiliation(s)
- S-H Chen
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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26
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Gambi CMC, Giordano R, Chittofrati A, Pieri R, Laurati M, Baglioni P, Teixeira J. Small-Angle Neutron Scattering of Mixed Ionic Perfluoropolyether Micellar Solutions. J Phys Chem B 2007; 111:1348-53. [PMID: 17286352 DOI: 10.1021/jp066102e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aqueous mixed micellar solutions of perfluoropolyether carboxylic salts with ammonium counterions have been studied by small-angle neutron scattering. Two surfactants differing in the tail length were mixed in proportions n2/n3 = 60/40 w/w, where n2 and n3 are the surfactants with two and three perfluoroisopropoxy units in the tail, respectively. The tails are chlorine-terminated. The mixed micellar solutions, in the concentration range 0.1-0.2 M and thermal interval 20-40 degrees C, show structural characteristics of the interfacial shell that are very similar to ammonium n2 micellar solutions previously investigated; thus, the physics of the interfacial region is dominated by the polar head and counterion. The shape and dimensions of the micelles are influenced by the presence of the n3 surfactant, whose chain length in the micelle is 2 A longer than that of the n2 surfactant. The n3 surfactant favors the ellipsoidal shape in the concentration range 0.1-0.2 M with a 1/2 ionization degree of n2 micelles. The very low surface charge of the mixed micelles is attributed to the increase in hydrophobic interactions between the surfactant tails, due to the longer n3 surfactant molecules in micelles. The closer packing of the tails decreases the micellar curvature and the repulsions between the polar heads, by surface charge neutralization of counterions migrating from the Gouy-Chapman diffuse layer, leading to micellar growth in ellipsoids with greater axial ratios.
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Affiliation(s)
- C M C Gambi
- Department of Physics, University of Florence and CNISM, v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
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Chen SH, Liu L, Fratini E, Baglioni P, Faraone A, Mamontov E. Observation of fragile-to-strong dynamic crossover in protein hydration water. Proc Natl Acad Sci U S A 2006; 103:9012-6. [PMID: 16751274 PMCID: PMC1482557 DOI: 10.1073/pnas.0602474103] [Citation(s) in RCA: 384] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2006] [Indexed: 11/18/2022] Open
Abstract
At low temperatures, proteins exist in a glassy state, a state that has no conformational flexibility and shows no biological functions. In a hydrated protein, at temperatures greater-- similar 220 K, this flexibility is restored, and the protein is able to sample more conformational substates, thus becoming biologically functional. This "dynamical" transition of protein is believed to be triggered by its strong coupling with the hydration water, which also shows a similar dynamic transition. Here we demonstrate experimentally that this sudden switch in dynamic behavior of the hydration water on lysozyme occurs precisely at 220 K and can be described as a fragile-to-strong dynamic crossover. At the fragile-to-strong dynamic crossover, the structure of hydration water makes a transition from predominantly high-density (more fluid state) to low-density (less fluid state) forms derived from the existence of the second critical point at an elevated pressure.
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Affiliation(s)
- S-H Chen
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Abstract
Measurements of pH in single-phase cytochrome c suspensions are reported. The pH, as determined by a glass electrode, has a fixed value. With the addition of salt, the supposedly fixed pH changes strongly. The pH depends on salt type and concentration and follows a Hofmeister series. A theoretical interpretation is given that provides insights into such Hofmeister effects. These occur generally in protein solutions. While classical electrostatic models provide partial understanding of such trends in protein solutions, they fail to explain the observed ion specificity. Such models neglect electrodynamic fluctuation (dispersion) forces acting between ions and proteins. We use a Poisson-Boltzmann cell model that takes these ionic dispersion potentials between ions and proteins into account. The observed ion specificity can then be accounted for. Proteins act as buffers that display similar salt-dependent pH trends not previously explained.
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Affiliation(s)
- M Boström
- Department of Physics and Measurement Technology, Linköping University, SE-581 83 Linköping, Sweden.
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Gambi CMC, Giordano R, Chittofrati A, Pieri R, Baglioni P, Teixeira J. Small-Angle Neutron Scattering of Ionic Perfluoropolyether Micellar Solutions: Role of Counterions and Temperature. J Phys Chem B 2005; 109:8592-8. [PMID: 16852016 DOI: 10.1021/jp0405815] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper reports a small-angle neutron scattering (SANS) characterization of perfluoropolyether (PFPE) aqueous micellar solutions with lithium, sodium, cesium and diethanol ammonium salts obtained from a chlorine terminated carboxylic acid and with two perfluoroisopropoxy units in the tail (n(2)). The counterion and temperature effects on the micelle formation and micellar growth extend our previous work on ammonium and potassium salts n(2) micellar solutions. Lithium, sodium, cesium and diethanol ammonium salts are studied at 0.1 and 0.2 M surfactant concentration in the temperature interval 28-67 degrees C. SANS spectra have been analyzed by a two-shell model for the micellar form factor and a screened Coulombic plus steric repulsion potential for the structure factor in the frame of the mean spherical approximation of a multicomponent system reduced to a generalized one component macroions system (GOCM). At 28 degrees C, for all the salts, the micelles are ellipsoidal with an axial ratio that increases from 1.6 to 4.2 as the counterion volume increases. The micellar core short axis is 13 A and the shell thickness 4.0 A for the alkali micelles, and 14 and 5.1 A for the diethanol ammonium micelles. Therefore, the core short axis mainly depends on the surfactant tail length and the shell thickness on the carboxylate polar head. The bulky diethanol ammonium counterion solely influences the shell thickness. Micellar charge and average aggregation number depend on concentration, temperature and counterion. At 28 degrees C, the fractional ionization decreases vs the counterion volume (or molecular weight) increase at constant concentration for both C = 0.1 M and C = 0.2 M. The increase of the counterion volume leads also to more ellipsoidal shapes. At C = 0.2 M, at 67 degrees C, for sodium and cesium micelles the axial ratio changes significantly, leading to spherical micelles with a core radius of 15 A, lower average aggregation number, and larger fractional ionization.
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Affiliation(s)
- C M C Gambi
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
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Mannini M, Gambinossi F, Baglioni P, Caminati G. Immobilization of a fluorescent dye in Langmuir-Blodgett films. Bioelectrochemistry 2004; 63:9-12. [PMID: 15110240 DOI: 10.1016/j.bioelechem.2003.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 09/17/2003] [Accepted: 09/25/2003] [Indexed: 11/19/2022]
Abstract
We immobilized a hemicyanine dye, Di-8-ANEPPS, in ordered thin films of an organic matrix, dihexadecyl phosphate (DHP), and we transferred the mixed monolayers onto solid support by the Langmuir-Blodgett technique. We used gold and quartz slides and indium tin oxide (ITO) evaporated on glass slides as substrates. The multilayers formation was confirmed by ellipsometric and contact angle measurements. The optical response of the nanostructures was investigated collecting UV-Vis absorption and fluorescence emission intensity profiles.
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Affiliation(s)
- M Mannini
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, Sesto Fiorentino Florence 50019, Italy
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31
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Bonechi C, Donati A, Martini S, Rossi C, Arduini A, Pochini A, Lonetti B, Baglioni P. Analysis of the p-tert-butylcalix[4]arene bis-crown Derivative (Dc3)-Acetonitrile Host−Guest Complexing Behavior by Nuclear Magnetic Resonance (NMR) Spectroscopy and Computational Methods. J Phys Chem B 2004. [DOI: 10.1021/jp037464e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Lonetti B, Fratini E, Chen SH, Baglioni P. Viscoelastic and small angle neutron scattering studies of concentrated protein solutions. Phys Chem Chem Phys 2004. [DOI: 10.1039/b316144g] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gambi CMC, Giordano R, Chittofrati A, Pieri R, Baglioni P, Teixeira J. Counterion and Temperature Effects on Aqueous Ionic Perfluoropolyether Micellar Solutions by Small-Angle Neutron Scattering. J Phys Chem A 2003. [DOI: 10.1021/jp030922z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. M. C. Gambi
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, Department of Physics, University of Messina and I.N.F.M., Salita Sperone 31, 98010 S.Agata, Messina, Italy, R and D Center, Colloid Laboratory, Solvay Solexis, vl. Lombardia 20, 20021 Bollate, Milano, Italy, Department of Chemistry, University of Florence and C.S.G.I., v. della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy, and Laboratoire Léon Brillouin, CEA-CNRS Saclay, 91191 Gif
| | - R. Giordano
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, Department of Physics, University of Messina and I.N.F.M., Salita Sperone 31, 98010 S.Agata, Messina, Italy, R and D Center, Colloid Laboratory, Solvay Solexis, vl. Lombardia 20, 20021 Bollate, Milano, Italy, Department of Chemistry, University of Florence and C.S.G.I., v. della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy, and Laboratoire Léon Brillouin, CEA-CNRS Saclay, 91191 Gif
| | - A. Chittofrati
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, Department of Physics, University of Messina and I.N.F.M., Salita Sperone 31, 98010 S.Agata, Messina, Italy, R and D Center, Colloid Laboratory, Solvay Solexis, vl. Lombardia 20, 20021 Bollate, Milano, Italy, Department of Chemistry, University of Florence and C.S.G.I., v. della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy, and Laboratoire Léon Brillouin, CEA-CNRS Saclay, 91191 Gif
| | - R. Pieri
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, Department of Physics, University of Messina and I.N.F.M., Salita Sperone 31, 98010 S.Agata, Messina, Italy, R and D Center, Colloid Laboratory, Solvay Solexis, vl. Lombardia 20, 20021 Bollate, Milano, Italy, Department of Chemistry, University of Florence and C.S.G.I., v. della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy, and Laboratoire Léon Brillouin, CEA-CNRS Saclay, 91191 Gif
| | - P. Baglioni
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, Department of Physics, University of Messina and I.N.F.M., Salita Sperone 31, 98010 S.Agata, Messina, Italy, R and D Center, Colloid Laboratory, Solvay Solexis, vl. Lombardia 20, 20021 Bollate, Milano, Italy, Department of Chemistry, University of Florence and C.S.G.I., v. della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy, and Laboratoire Léon Brillouin, CEA-CNRS Saclay, 91191 Gif
| | - J. Teixeira
- Department of Physics, University of Florence and I.N.F.M., v. G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy, Department of Physics, University of Messina and I.N.F.M., Salita Sperone 31, 98010 S.Agata, Messina, Italy, R and D Center, Colloid Laboratory, Solvay Solexis, vl. Lombardia 20, 20021 Bollate, Milano, Italy, Department of Chemistry, University of Florence and C.S.G.I., v. della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy, and Laboratoire Léon Brillouin, CEA-CNRS Saclay, 91191 Gif
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Mecheri B, Baglioni P, Pieroni O, Caminati G. Molecular switching in nano-structured photochromic films of biopolymers. Materials Science and Engineering: C 2003. [DOI: 10.1016/j.msec.2003.09.132] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Trimarchi H, Mongitore MR, Baglioni P, Forrester M, Freixas EAR, Schropp M, Pereyra H, Alonso M. N-acetylcysteine reduces malondialdehyde levels in chronic hemodialysis patients--a pilot study. Clin Nephrol 2003; 59:441-6. [PMID: 12834176 DOI: 10.5414/cnp59441] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Oxidative stress has been implicated in the development of endothelial damage in hemodialysis (HD). We have assessed the effects of N-acetylcysteine (NAC), a compound with antioxidant effects, on malondialdehyde (MDA), a marker of oxidative stress on lipid peroxidation. METHODS A clinical trial was conducted in which 24 chronic HD patients were divided into 2 groups according to gender, age, time on HD and cause of renal failure. The NAC group (n = 12) received 600 mg of NAC twice a day for 30 days. The remaining patients constituted the control group (n = 12). MDA levels were measured pre- and post-dialysis at the beginning of the study (baseline) and on day 30 (30 days). RESULTS Baseline pre- and post-dialysis MDA levels were not different between both groups and were above normal values. A significant decrease was found in the NAC group when either pre- or post-dialysis MDA levels were compared to the corresponding control group levels on day 30 (pre-dialysis NAC vs control group 3.01 +/- 0.6 vs 4.5 +/- 0.73 micromol/l, p < 0.0001, post-dialysis NAC vs control group 2.76 +/- 0.5 vs 4.39 +/- 0.7 micromol/l, p < 0.0001). Only in the NAC group were pre-dialysis MDA 30-day levels different from pre-dialysis baseline levels (3.01 +/- 0.6 vs 5.07 +/- 1.6 micromol/l, p < 0.002). Post-dialysis MDA 30-day concentrations were significantly lower than post-dialysis MDA baseline levels (2.76 +/- 0.5 vs 4.32 +/- 0.7 micromol/l, p < 0.002) and pre-dialysis MDA 30-day measurements (2.76 +/- 0.5 vs 3.01 +/- 0.6 micromol/l, p < 0.011). CONCLUSIONS MDA levels are elevated in chronic HD patients and are not significantly reduced by HD. NAC significantly reduces malondialdehyde levels in chronic HD patients.
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Affiliation(s)
- H Trimarchi
- Division of Nephrology and Biochemistry Laboratory, Hospital Británico de Buenos Aires, Argentina.
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Affiliation(s)
- M. Bonini
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3 - Sesto Fiorentino, 50019 Florence, Italy
| | - U. Bardi
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3 - Sesto Fiorentino, 50019 Florence, Italy
| | - D. Berti
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3 - Sesto Fiorentino, 50019 Florence, Italy
| | - C. Neto
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3 - Sesto Fiorentino, 50019 Florence, Italy
| | - P. Baglioni
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3 - Sesto Fiorentino, 50019 Florence, Italy
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Liu YC, Baglioni P, Teixeira J, Chen SH. Structure and Interaction of Lithium Dodecyl Sulfate Micelles in the Presence of Li-Specific Macrocyclic Cage: A Study by SANS. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100091a041] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Baglioni P, Carla M, Dei L, Martini E. Interaction between .alpha.-poly(.gamma.-methyl-L-glutamate) and 5- and 16-doxylstearic acids: a monolayer and ESR study. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100290a036] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Faraone A, Chen SH, Fratini E, Baglioni P, Liu L, Brown C. Rotational dynamics of hydration water in dicalcium silicate by quasielastic neutron scattering. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 65:040501. [PMID: 12005795 DOI: 10.1103/physreve.65.040501] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2002] [Indexed: 05/23/2023]
Abstract
Quasielastic neutron scattering (QENS) has been used to investigate the single-particle dynamics of interfacial water in dicalcium silicate (C2S)/water paste. Our previous neutron-scattering studies on interfacial water have focused attention on the translational dynamics of the center of mass of water molecules. In this paper, we have collected QENS data on a wider range of wave-vector transfer so that both translational and rotational motions of water molecules are detected. The data have been analyzed by models for translation and rotation we recently proposed for supercooled water. The evolution of the parameters describing the relaxational dynamics of water embedded in the C2S matrix is given at temperature T=303 K as a function of the curing time.
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Affiliation(s)
- A Faraone
- Department of Nuclear Engineering, 24-209 MIT, Cambridge, Massachusetts 02139, USA
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Fratini E, Chen SH, Baglioni P, Cook JC, Copley JRD. Dynamic scaling of quasielastic neutron scattering spectra from interfacial water. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 65:010201. [PMID: 11800665 DOI: 10.1103/physreve.65.010201] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2001] [Indexed: 05/23/2023]
Abstract
A method for analysis of high-resolution quasielastic neutron scattering (QENS) spectra of water in porous media is proposed and applied to the case of water in hydrated tricalcium and dicalcium silicates. We plot the normalized frequency-dependent susceptibility as a function of a scaling variable [omega]/omega(p), where omega(p) is the peak position of the susceptibility function. QENS data have been scaled into a single master curve and fitted with an empirical formula proposed by Bergman to obtain three independent parameters describing the relaxation dynamics of hydration water in calcium silicates.
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Affiliation(s)
- E Fratini
- Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Randazzo D, Berti D, Briganti F, Baglioni P, Scozzafava A, Di Gennaro P, Galli E, Bestetti G. Efficient polycyclic aromatic hydrocarbons dihydroxylation in direct micellar systems. Biotechnol Bioeng 2001; 74:240-8. [PMID: 11400097 DOI: 10.1002/bit.1113] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Optimization of whole-cell bioconversion of the polycyclic aromatic hydrocarbons (PAHs) anthracene, phenanthrene, and naphthalene to the enantiomerically pure corresponding cis-dihydroxydihydro derivatives by the Escherichia coli JM109 (pPS1778) recombinant strain, carrying the naphthalene dioxygenase and corresponding regulatory genes cloned from Pseudomonas fluorescens N3, in micellar systems, is presented. We show that direct microemulsion systems, where a nonionic surfactant such as 1.5% (v/v) Triton X-100 plus 0.6% to 1.0% (v/v) selected oils are able to solubilize the PAHs tested at relatively high concentrations (initial concentrations in the reaction medium > or =10 mM for naphthalene and phenanthrene and > or =2 mM for anthracene), and allow for more efficient substrate bioconversion. These media, while not affecting bacteria viability and performance, provide increased efficiency and final product yields (100% for naphthalene, >30% for anthracene, >60% for phenanthrene). The phase behavior of the direct microemulsion systems for the different substrates and oils utilized was monitored as a function of their volume fraction by light scattering experiments, and related to the bioconversion results. For anthracene and phenanthrene, the dihydroxylated products have an inhibitory effect on the conversion reactions, thus hindering complete turnover of the substrates. We ascertain that such inhibition is reversible because removal of the products formed allowed the process to start over at rates comparable to initial rates. To allow for complete conversion of the PAHs tested a stepwise or continuous separation of the product formed from the micellar reaction environment is being developed.
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Affiliation(s)
- D Randazzo
- Laboratorio di Chimica Bioinorganica, Dipartimento di Chimica, Università di Firenze, Via Della Lastruccia 5, 50019 Florence, Italy
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Fratini E, Chen SH, Baglioni P, Bellissent-Funel MC. Age-dependent dynamics of water in hydrated cement paste. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:020201. [PMID: 11497549 DOI: 10.1103/physreve.64.020201] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2001] [Indexed: 11/07/2022]
Abstract
Self-dynamics of water molecules has been studied in hydrated tricalcium silicate as functions of temperature, aging, and in the presence of an additive. A dynamical model taking into account the existence of "immobile water" and "glassy water" has been used to analyze quasielastic neutron spectrometer spectra. We deduced the fraction of the immobile water (p), the stretch exponent (beta), and the average relaxation time (tau) of the glassy water. A quantitative picture for an aspect of the kinetics of the curing process and the structural relaxation parameters of the glassy water have been established.
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Affiliation(s)
- E Fratini
- Department of Nuclear Engineering, 24-209, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Berti D, Randazzo D, Briganti F, Baglioni P, Scozzafava A, Di Gennaro P, Galli E, Bestetti G. Direct micellar systems as a tool to improve the efficiency of aromatic substrate conversion for fine chemicals production. J Inorg Biochem 2000; 79:103-8. [PMID: 10830854 DOI: 10.1016/s0162-0134(99)00236-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Whole-cell bioconversion of naphthalene to (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene by Escherichia coli JM109(pPS1778) recombinant strain, carrying naphthalene dioxygenase and regulatory genes cloned from Pseudomonas fluorescens N3, in direct micellar systems is optimized as an example of fine chemicals bioproduction from scarcely water-soluble substrates. The oxygen insertion into the aromatic substrate, which stops at the enantiomerically pure cis dihydroxylated product, is performed in direct microemulsion systems, where a non-ionic surfactant stabilizes naphthalene containing oil droplets in an aqueous medium. These media provide an increased substrate solubility so that a homogeneous reaction can be carried out, while not affecting bacteria viability and performances. The influence of the chemical nature of the oil is investigated. The phase behavior of the direct microemulsion system was monitored for three different oils as a function their volume fraction and characterized through light scattering. The addition of isopropyl palmitate, oleic acid, or glyceryl trioleate, 0.6-1.2% v/v to the micellar systems, led to an increase of the substrate concentration in the solution and particularly its bioavailability, allowing faster catalytic conversions. All these systems resulted in being suitable for catalytic conversions of aromatic compounds. Although the nature of the oil does have a deep effect on the phase behavior of the micellar systems, in the present investigation no differences in the yields and in the rates of product formation of the enzymatic system were observed on changing the oil, thus showing that in this case the substrate concentration or bioavailability is not the rate-limiting step.
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Affiliation(s)
- D Berti
- Dipartimento di Chimica, Università di Firenze and CSGI, Florence, Italy
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Baglioni P, Demets R, Verga A. ESA payloads and experiments on the Foton-12 mission. ESA Bull 2000; 101:96-107. [PMID: 11758571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The international Foton-12 mission in September 1999 was a milestone in terms of payload mass, complexity and scientific diversity. ESA's contribution amounted to an unprecedented 240 kg--almost half of Foton's total payload. The Agency's 11 experiments covered fluid physics, biology, radiation dosimetry, materials science and meteoritics. This article describes the mission from an ESA perspective and highlights the initial results.
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Affiliation(s)
- P Baglioni
- ESA Directorate of Manned Spaceflight and Microgravity, ESTEC, Noordwijk, The Netherlands
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Capuzzi G, Baglioni P, Gambi CM, Sheu EY. Percolation phenomenon of calcium bis(2-ethylhexyl) sulfosuccinate water-in-oil microemulsions by conductivity and dielectric spectroscopy measurements. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1999; 60:792-8. [PMID: 11969820 DOI: 10.1103/physreve.60.792] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/1998] [Revised: 01/11/1999] [Indexed: 04/18/2023]
Abstract
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 normal decane microemulsions allows detection of an important difference. The percolation below threshold is dynamic for the sodium-based microemulsions, accounting for the formation of clusters of droplets, whereas calcium-based microemulsions show a static percolation. For this system, the coalescence of droplets begins to occur below threshold at phi approximately 12%.
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Affiliation(s)
- G Capuzzi
- Department of Chemistry and CSGI, University of Florence, 50121 Florence, Italy
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Affiliation(s)
- M. Campagna
- Department of Chemistry, University of Florence, 50121 Florence, Italy, and Department of Physics, University of Florence, and INFM, 50125 Florence, Italy
| | - L. Dei
- Department of Chemistry, University of Florence, 50121 Florence, Italy, and Department of Physics, University of Florence, and INFM, 50125 Florence, Italy
| | - C. M. C. Gambi
- Department of Chemistry, University of Florence, 50121 Florence, Italy, and Department of Physics, University of Florence, and INFM, 50125 Florence, Italy
| | - P. Lo Nostro
- Department of Chemistry, University of Florence, 50121 Florence, Italy, and Department of Physics, University of Florence, and INFM, 50125 Florence, Italy
| | - S. Zini
- Department of Chemistry, University of Florence, 50121 Florence, Italy, and Department of Physics, University of Florence, and INFM, 50125 Florence, Italy
| | - P. Baglioni
- Department of Chemistry, University of Florence, 50121 Florence, Italy, and Department of Physics, University of Florence, and INFM, 50125 Florence, Italy
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Bottiroli G, Croce AC, Balzarini P, Locatelli D, Baglioni P, Lo Nostro P, Monici M, Pratesi R. Enzyme-assisted cell photosensitization: a proposal for an efficient approach to tumor therapy and diagnosis. The rose bengal fluorogenic substrate. Photochem Photobiol 1997; 66:374-83. [PMID: 9297981 DOI: 10.1111/j.1751-1097.1997.tb03161.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Rose bengal, a xanthene derivative among the most efficient producer of singlet oxygen, was submitted to a chemical modification consisting in the introduction of an acetate group into the aromatic ring fluorophore structure. The acetate group acts as a quencher, thus inactivating both fluorescence and photosensitization properties of the molecule. In the modified structure, rose bengal acts as a fluorogenic substrate giving rise to the cellular reaction termed fluorochromasia. The acetate group is recognized by a carboxylic esterase activity that splits it. Removal of the quencher group results in restoring the native structure of photosensitizer inside the cells. The intracellular turnover of rose bengal acetate was studied in rat glioma-derived cultures cells, in terms of the balance of the processes of influx and enzyme hydrolysis of the fluorogenic substrate, and of the efflux of the fluorescent product. A large intracellular accumulation of photosensitizer is obtained when treatments are performed with the fluorogenic substrate, even at the drug concentration at which rose bengal does not enter the cells. The intracellular localization allows rose bengal to exert a more effective photosensitization effect. Provided that the quencher group is selected according to the metabolic properties of the tumor cells, the use of fluorogenic substrates as photosensitizer precursors could improve fluorescence diagnosis and the photodynamic therapy of tumors, exploiting the biological properties that distinguish pathological from normal conditions.
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Affiliation(s)
- G Bottiroli
- Centro di Studio per l'Istochimica CNR, Dipartimento di Biologia Animale, Università, Pavia, Italy.
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