Publications by authors named "Alessandra Di Tullio"

Objective: Fiber Optic RealShape (FORS) is a new technology that visualises the full three dimensional (3D) shape of guidewires using an optical fibre embedded in the device. Co-registering FORS guidewires with anatomical images, such as a digital subtraction angiography (DSA), provides anatomical context for navigating these devices during endovascular procedures. The objective of this study was to demonstrate the feasibility and usability of visualising compatible conventional navigation catheters, together with the FORS guidewire, in phantom with a new 3D Hub technology and to understand potential clinical benefits.

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  • The study analyzed particulate matter in eight size fractions (10 to 0.43 micrometers) using HS-SPME/GC-MS and SEM/EDX techniques to determine organic components and elemental composition.
  • HS-SPME proved to be an efficient method, requiring minimal sample amounts and avoiding solvents while still providing selective and clean results.
  • Findings indicated a strong relationship between particle size, composition, and emission sources, with smaller particles containing more elemental carbon and organic compounds, including carcinogens like PAHs from both rural and polluted areas.
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  • Recent advancements in mass spectrometry allow scientists to study supramolecular interactions in the gas phase, particularly focusing on biomolecular interactions that typically occur in solution.
  • The electrospray technique enables soft ionization, which preserves noncovalent bonds, aiding in the direct analysis of biomolecular complexes, including various interactions like protein-ligand and DNA-drug.
  • This new method, referred to as 'supramolecular mass spectrometry,' also facilitates chiral recognition and provides insights into complex formations with host molecules such as crown ethers and cyclodextrins.
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The preparation and characterization of a new microperoxidase obtained from proteinase K-treated cytochrome c(552) from Marinobacter hydrocarbonoclasticus (previously known as Pseudomonas nautica) are presented. This microperoxidase (MMP-5) has novel structural properties relative to previously reported microperoxidases, as the two intervening amino acid (X) residues within the consensual CXXCH c-type heme binding motif are missing, yielding a heme-pentapeptide with increased solubility in aqueous solvents and a 1-2 order of magnitude higher stability of the monomeric state relative to canonical microperoxidases. The electronic spectra in the near-UV and visible regions have been studied as a function of MMP-5 concentration and pH.

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  • Microperoxidases are small heme-peptides derived from cytochrome c that possess peroxidase activity and have potential applications.
  • MMP-5, a novel microperoxidase from Marinobacter hydrocarbonoclasticus, was characterized using mass spectrometry and is structurally simplified for better water solubility, lacking certain amino acids.
  • Upon ionization, MMP-5 exhibits a notable tendency to reduce its iron protoporphyrin structure, which is indicated by observable mass shifts.
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Lignin, a resistant cell-wall constituent of all vascular plants that consists of ether and carbon-linked methoxyphenols, is still far from being structurally described in detail. The main problem in its structural elucidation is the difficulty of isolating lignin from other wood components without damaging lignin itself. Furthermore, the high number and variegated forms of linkages that occur between the monomeric units and the chemical resistance of certain ether bonds limit the extent to which analytical and degradation procedures can be used to elucidate the lignin structure.

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The catalytic activity of alpha-chymotrypsin on a model and a peptide substrate, in the supramolecular system "enzyme-surfactant" in water solution, has been studied by electrospray ionization mass spectrometry. Hydrolysis of N-succinyl-L-phenylalanine p-nitroanilide as the model compound, catalysed by alpha-chymotrypsin in the presence of monomeric cetyltributylammonium bromide, has been followed by UV and ESI-MS detection. Kinetic data, which are essentially identical independent of their determination techniques, show a twelve fold improvement of the enzyme catalytic efficiency when compared with the reaction carried out in the absence of the additive.

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The Dufour's gland content of workers of two ant species of the genus Messor has been analyzed by solid-phase microextraction and gas chromatography with mass spectrometry (GC/MS). The structures of the compounds in the pheromonal mixtures have been determined. In both cases only one intact gland, inserted in a properly dimensioned capillary vial, is sufficient to produce a clean and fully interpretable GC/MS profile.

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Lichens are ubiquitous organisms formed by symbiotic associations of fungal hyphas and algae that also grow under often extreme environmental conditions. They produce secondary metabolites, the so-called lichen substances, whose structural characterization can give an important contribution to lichen taxonomy. Lichens are also widely employed as biomonitors of atmospheric pollution; being epiphyte organisms they tend, in fact, to accumulate exogenous compounds.

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The enantiomers of carnitine are converted on-line in the injection port of a gas chromatograph into beta-hydroxy-gamma-butyrolactones and are separated on a derivatized beta-cyclodextrin chiral stationary phase.

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