Search results for "Spectroscopy"

Twenty Years of Airborne Water Vapor and Total Water Measurements of a Diode Laser Based Photoacoustic Instruments

2020

We present relevant issues collected over twenty years of development and operation of an airborne water vapour / total water detector based on photoacoustic spectroscopy. The WaSulHygro instrument possesses high selectivity, short response time, and wide dynamic range, that are key requirements against trace gas measurement systems for applications in atmospheric sciences. Besides the major properties of WaSul-Hygro we discuss our efforts to develop a robust instruments that have proved its long-term reliability over the last fifteen years operating on-board a commercial aircraft within the framework of the CARIBIC project.2

Electron spectroscopy with the SAGE spectrometer

2016

A device called the SAGE (Silicon And GErmanium) spectrometer, designed for in-beam electron spectroscopy, is introduced in this work. A detailed description to the technical aspects of the device is given along with several examples of analytical procedures related to work done with the device. The radial ltering method and veto/add-back algorithms are tools for improving the quality of the electron-gamma data whilst the time-gate selection procedure helps in determining absolute internal conversion coe cients without reference points. Two very di erent types of experiments with results obtained from the electron data are introduced and analysed. Coulomb excitation is used to probe 154Sm a…

Sequential dissociation of insulin amyloids probed by high pressure Fourier transform infrared spectroscopy

2012

High Pressure (HP) Fourier Transform Infrared Spectroscopy (FTIR) has been here employed to investigate the thermodynamic stability of bovine pancreatic insulin (BPI) amyloids. Once the aggregation reaction has started, the backbone arrangement of the proteins forming the amyloid is known to reach a stationary phase in few hours; after this time the infrared absorption of fibrils becomes stable. It is here shown how the further stabilization of the structure during the stationary phase can be probed via FTIR spectroscopy, through the observation of the high pressure behaviour of fibrils formed at different maturation stages. We report on the high pressure fragmentation of insulin amyloids, …

FTIR analysis of the high pressure response of native insulin assemblies

2013

It is widely recognized that a central role in conferring stability to the structure of proteins against misfolding and aggregation is played by the formation of oligomers. The case of insulin is prototypical in this respect: in our body it is stored up in stable inactive hexameric assemblies whereas only in its monomeric form it recovers the role of regulating carbohydrate and fat metabolism. In the present paper, exploiting the optimal coupling between FTIR spectroscopy and diamond anvil cell technique, we probe the stability of different insulin oligomeric forms under high pressure, namely over the ranges 0-15 kbar for water solution and 0-80 kbar for dry powder. Results obtained show di…

Interactions of α2β1 integrin and its ligands, type I collagen and echovirus 1

2015

Radio-optical scrutiny of compact AGN

2010

We study the correlations between the VLBA (Very Long Baseline Array) radio emission at 15GHz, extended emission at 151MHz, and optical nuclear emission at 5100{AA} for a complete sample of 135 compact jets. We use the partial Kendall's tau correlation analysis to check the link between radio properties of parsec-scale jets and optical nuclear luminosities of host active galactic nuclei (AGN). Cone search capability for table J/A+A/520/A62/table3 (Optical and radio parameters of 135 AGN)

Sesquiterpene compounds from Inula Viscosa

2007

Two new compounds, 2,5-dihydroxyisocostic acid and 2,3-dihydroxycostic acid together with three known sesquiterpene compounds, Isocostic acid, Carabrone and Tomentosin, have been isolated from the acetone extract of Inula viscosa (L.) Aiton. The structures of all new compounds were determined by spectroscopic methods, in particular 1D and 2D (1)H- and (13)C-NMR. The (13)C-NMR spectra of Isocostic acid and of Tomentosin are reported here for the first time.

Trap-assisted studies of odd, neutron-rich isotopes from Tc to Pd

2012

We review the present and future of trap-assisted structure studies of odd, neutron-rich Tc, Ru, Rh and Pd isotopes at the limits of present experimental techniques. These nuclei of refractory elements are produced in light-particle induced fission and filtered by their mass number with the IGISOL mass separator. Further mass separation with the JYFLTRAP Penning trap system provides a clean, monoisotopic beam perfectly suited for precise nuclear spectroscopy. Connecting the IGISOL and the JYFLTRAP facilities to the recently installed MCC30/15 cyclotron opens new prospects for post-trap spectroscopy of very exotic, neutron-rich nuclei. peerReviewed

Geminal Ionic Liquids: A Combined Approach to Investigate their Tridimensional Structure

2009

Different investigations, such as 1D and 2D NMR spectroscopy, resonance light scattering spectroscopy and molecular dynamics simulations, have been jointly used to achieve a deeper understanding of the degree of structural order in two geminal ionic liquids. In particular, 3,3’-di-n-butyl-1,1’-(1,3- phenylenedimethylene)diimidazolium and 3,3’-di-n-butyl-1,1’-(1,4-phenylenedimethylene) diimidazolium bis- ACHTUNGTRENUNG[bis(trifluoromethanesulfonyl)imide] have been studied. These geminal ionic liquids were chosen because of the presence of both a rigid phenylenedimethylene link between two imidazolium rings, which should give a high degree of order to the solvent system, and the different sha…

The effect of the cation p-surface area on the 3D organization and catalytic ability of imidazolium-based ionic liquids

2011

The dichotomic nature of ionic liquids (ILs, simple solvents or supramolecular fluids) induced us to carry out a structural investigation of some mono-and dicationic ionic liquids using 1D and 2D NMR, resonance light scattering, and UV/Vis spectroscopy. Ionic liquids with different cation π-surface areas were used, namely [bmim][NTf2], [Bzmim][NTf 2], [Bzbim][NTf2], [p-Xyl-(bim)2][NTf 2]2, and [m-Xyl-(bim)2][NTf2] 2 [bmim = 1-butyl-3-methylimidazolium, Bzmim = 1-benzyl-3- methylimidazolium, Bzbim = 1-benzyl-3-butylimidazolium, NTf2 = bis(trifluoromethansulfonyl)imide]. In order to verify to what extent the structural investigation, coupled with the determination of solvent parameters, could…