Search results for "MAS NMR"
showing 10 items of 29 documents
Pitfalls to be considered on the metabolomic analysis of biological samples by HR-MAS
2014
HR-MAS (High-Resolution Magic AngleSpinning) is considered a powerfultechnique for metabolomic studies ofbiological samples that provides “intact”tissue spectra (Cheng et al., 1998; Waterset al., 2000; Sitter et al., 2002; Martinez-Bisbal et al., 2004; Payne et al., 2006;Coen et al., 2007; Bathen et al., 2010).The performance of HR-MAS, fol-lowed by quantitative histopathology hasdemonstrated that, despite some changes,HR-MAS can preserve approximately thetissue histopathologic features producingwell-resolved spectra of cellular metabo-lites (Cheng et al., 2000). Nevertheless,therearesomeaspectsarousedintheliter-ature about the possible biochemical andstructural changes that can occur durin…
Consequence of litter removal on pedogenesis: A case study in Bachs and Irchel (Switzerland)
2016
In forests, soils contain at least twice as much carbon than plants that mostly grow in the upper layers. Litter at the interface between soils and the atmosphere regulates a variety of biogeochemical cycles, which are important for both plants and soils and have possible implications for other environmental components. We have compared leachates collected during an incubation experiment on: a) beech and oak leaves; b) organic subhorizons OLn, OLv, OF, and mineral A horizon; c) treated with litter removal (and untreated) plots, to assess the changes in the chemical composition of the litter layers and leachates during weathering and their influence on the underlying horizons. . Two differen…
The Acqualadrone Rostrum: a physical-chemical investigation to understand the Material History
2013
The aim of this work is to define the conservation state and to ascertain the provenance of raw materials used in the construction of the Acqualadrone Rostrum. In 2008 the rostrum (an offensive naval weapon mounted on the prow at the waterline), from an ancient warship was recovered from the Mediterranean near Acqualadrone, Messina, Sicily. The archaeological discovery has led to the need for scientific research in order to plan the conservation treatment of this artefact. The discovery is exceptional because of the presence of a wooden section from the original ship. The physical-chemical investigation, by using some complementary spectroscopic techniques, was focused on the characterizati…
Solid state nmr characterization of the waterlogged wooden part of Acqualadrone roman rostrum
2014
The roman rostrum found in the sea of Acqualadrone (ME) was characterized in our previous papers. In the present work solid state NMR spectroscopy was applied on a wooden sample of the same artefact collected by coring and divided in four parts in order to correlate the conservation state to the depth. Results were compared with those obtained for a modern wood of the same species. A structural study was performed by the acquisition of 13C Cross Polarization Magic Angle Spinning (13C CP MAS NMR) spectra. These spectra were acquired to assign the chemical shifts of the species that are present in the wooden matrix. In addition the spectra analysis allowed us to determine the cellulose crysta…
Physicochemical Characterization Of Ancient Paper And Parchment With Solid State Nuclear Magnetic Resonance
2014
Historical paper and parchment are widely investigated in order to comprehend mechanisms of degradation and to plan proper conservation interventions. NMR spectroscopy is a powerful tool that allows to the changes occurring during the degradation process and to get information on the state of conservation. In this work a Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (13C{1H} CP MAS NMR) study of a 16th century book is reported. The physicochemical characterization of paper samples collected from the book was performed through the evaluation of intensity and the changes in line width of signals in the spectra. 13C{1H} CP MAS NMR spectra of paper samples collected from th…
Average versus local structure in K2NiF4-type LaSrAlO4: direct experimental evidence of local cationic ordering
2012
The long-range ordering of a crystalline material can be accurately determined by analyzing the Bragg intensities and positions. In contrast, direct observation of short-range ordering in crystalline materials, which is increasingly considered of fundamental importance to unravel the structure-property relationships that underpin their technological applications, is a challenging task. In this study we have investigated the structure of LaSrAlO4, a representative example of compounds with the K2NiF4-type structure. By the combined use of synchrotron and neutron diffraction, pair distribution function analysis, Al-27 MQMAS NMR and atomistic simulations we have highlighted differences between…
Chromium liquid waste inertization in an inorganic alkali activated matrix: Leaching and NMR multinuclear approach
2015
A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈ 2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid ha…
The metabolic profile of lemon juice by proton HR-MAS NMR: the case of the PGI Interdonato Lemon of Messina
2015
We have studied by means of High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) the metabolic profile of the famous Sicilian lemon known as 'Interdonato Lemon of Messina PGI'. The PGI Interdonato Lemon of Messina possesses high organoleptic and healthy properties and is recognised as one of the most nutrient fruits. In particular, some of its constituents are actively studied for their chemo-preventive and therapeutic properties. In this paper, we have determined by means of HR-MAS NMR spectroscopy the molar concentration of the main metabolites constituent the juice of PGI Interdonato Lemon of Messina in comparison with that of the not-PGI Interdonato Lemon of Turk…
Synthesis, Characterization and Catalytic Activity of mesoporous Mn-MCM-41 materials
2011
MCM-41 has been synthesized at two different pH using cetyl-trimethylammonium bromide (CTAB) surfactant as template and adding the silica precursor to aqueous solutions containing CTAB. The obtained solids were calcined at 600 ◦C for 4 h. Mn-MCM-41 powders with different Mn/Si molar ratios were prepared using the incipient wetness method, followed by calcination at 550 ◦C for 5 h. At the end of the impregnation process the powders colour changed from white to brown whose intensity depends on manganese quantity. The materials characterization was performed by X-ray diffraction, N2 adsorption, 29Si Cross Polarization–Magic Angle Spinning NMR, and X-ray Photoelectron Spectroscopy. The effects …
Inverse Conformational Selection in Lipid–Protein Binding
2021
International audience; Interest in lipid interactions with proteins and other biomolecules is emerging not only in fundamental biochemistry but also in the field of nanobiotechnology where lipids are commonly used, for example, in carriers of mRNA vaccines. The outward-facing components of cellular membranes and lipid nanoparticles, the lipid headgroups, regulate membrane interactions with approaching substances, such as proteins, drugs, RNA, or viruses. Because lipid headgroup conformational ensembles have not been experimentally determined in physiologically relevant conditions, an essential question about their interactions with other biomolecules remains unanswered: Do headgroups excha…