Search results for "IR spectroscopy"

THE SAN VITO WOODEN PULPIT FROM MUSEO DIOCESANO OF PALERMO, ITALY: MULTIDISCIPLINARY APPROACH AND ANALYTICAL TECHNIQUES FOR DATING AND RESTORATION

2017

The aim of the present research is to investigate the constitutive materials and the execution techniques of San Vito wooden pulpit from Museo Diocesano of Palermo (Italy) and to provide helpful information to dating it in addition to technical, historical and artistic evaluations. The pulpit, attributed to unknown artist, belongs to the decorative arts and the most relevant feature is its double dating, in addition to the singular painting technique: it has a linear structure typical of XIXth century and three polychrome and gilded panels probably dated to the end of XVIIth century. This paper describes the application of analytical techniques (imaging diagnostics techniques, Scanning Elec…

OH-related infrared bands in oxide glasses

2004

Crypthecodinium cohnii Growth and Omega Fatty Acid Production in Mediums Supplemented with Extract from Recycled Biomass

2022

Crypthecodinium cohnii is a marine heterotrophic dinoflagellate that can accumulate high amounts of omega-3 polyunsaturated fatty acids (PUFAs), and thus has the potential to replace conventional PUFAs production with eco-friendlier technology. So far, C. cohnii cultivation has been mainly carried out with the use of yeast extract (YE) as a nitrogen source. In the present study, alternative carbon and nitrogen sources were studied: the extraction ethanol (EE), remaining after lipid extraction, as a carbon source, and dinoflagellate extract (DE) from recycled algae biomass C. cohnii as a source of carbon, nitrogen, and vitamins. In mediums with glucose and DE, the highest specific biomass gr…

Roadmap on STIRAP applications

2019

STIRAP (stimulated Raman adiabatic passage) is a powerful laser-based method, usually involving two photons, for efficient and selective transfer of populations between quantum states. A particularly interesting feature is the fact that the coupling between the initial and the final quantum states is via an intermediate state, even though the lifetime of the latter can be much shorter than the interaction time with the laser radiation. Nevertheless, spontaneous emission from the intermediate state is prevented by quantum interference. Maintaining the coherence between the initial and final state throughout the transfer process is crucial. STIRAP was initially developed with applications in …

Conformational investigation of alpha,beta-dehydropeptides. VIII. N-acetyl-alpha,beta-dehydroamino acid N'-methylamides: conformation and electron de…

2009

The Fourier transform infrared spectra are analyzed in the regions of Vs(N-H), amide I, amide II and Vs(C alpha = C beta) bands for a series of Ac-delta Xaa-NHMe, where delta Xaa = delta Ala, (Z)-delta Abu, (Z)-delta Leu, (Z)-delta Phe and delta Val, to determine the predominant solution conformation of these alpha,beta-dehydropeptide-related molecules and the electron distribution perturbation in their amide bonds. The measurements were performed in dichloromethane (DCM). To confirm and rationalize the assignments, the spectra of the respective series of saturated Ac-Xaa-NHMe, recorded in DCM, and the spectra of these two series of unsaturated and saturated compounds, recorded in acetonitr…

Characterization of prehispanic cosmetics found in a burial of the ancient city of Teotihuacan (Mexico)

2012

The present paper reports the chemical data obtained on samples of pigmenting materials contained in 31 miniature vessels found in a burial found in Teopancazco, a multiethnic neighborhood center located in the southeastern sector of the archaeological site of Teotihuacan (Central Mexico) and the analytical protocol established for the complete characterization of these archaeological materials. For this purpose a multi-technique approach based on the combination of several non destructive and micro-destructive instrumental techniques, namely, light microscopy (LM), scanning electron microscopy-X-ray micro-analysis (SEMe EDX), transmission electron microscopy (TEM), voltammetry of micropart…

Structure−Dynamics Coupling between Protein and External Matrix in Sucrose-Coated and in Trehalose-Coated MbCO:  An FTIR Study

2004

We performed FTIR measurements on carboxy-myoglobin (MbCO) embedded in a sucrose−water matrix to study the degrees of freedom coupling between protein and external matrix in such a system. The work was undertaken on the light of recent results by Giuffrida et al. (J. Phys. Chem. B 2003, 107, 13211−13217), who evidenced, in trehalose-coated MbCO, a structured water−sugar environment of the protein, tightly coupled to the heme pocket structure. Such information was obtained through a suitable analysis of the temperature dependence of the CO stretching and of the water association bands in samples of different content of residual water. We applied here the same analysis to sucrose-coated MbCO.…

N-(6-Methylpyridin-2-yl)mesitylenesulfonamide and acetic acid--a salt, a cocrystal or both?

2015

In the solid obtained fromN-(6-methylpyridin-2-yl)mesitylenesulfonamide and acetic acid, the constituents interactviatwo N—H...O hydrogen bonds. The H atom situated in one of these short contacts is disordered over two positions: one of these positions is formally associated with an adduct of the neutral sulfonamide molecule and the neutral acetic acid molecule, and corresponds to a cocrystal, while the alternative site is associated with salt formation between a protonated sulfonamide molecule and deprotonated acetic acid molecule. Site-occupancy refinements and electron densities from difference Fourier maps suggest a trend with temperature, albeit of limited significance; the cocrystal i…

Specific Protein Docking to Chelator Lipid Monolayers Monitored by FT-IR Spectroscopy at the Air–Water Interface

1996

Role of residual water hydrogen bonding in sugar/water/biomolecule systems: a possible explanation fortrehalose peculiarity

2007

We report on the set of experimental and simulative evidences which enabled us to suggest how biological structures embedded in a non-liquid water–saccharide solvent are anchored to the surrounding matrix via a hydrogen bond network. Such a network, whose rigidity increases by decreasing the sample water content, couples the degrees of freedom of the biostructure to those of the matrix and gives place to protein–saccharide–water structures (protein–solvent conformational substates). In particular, the whole set of data evidences that, while the protein–sugar interaction is well described in terms of a water entrapment hypothesis, the water replacement hypothesis better describes the sugar–m…