Search results for "Spectroscopy."
showing 10 items of 9110 documents
Selection of Membrane RNA Aptamers to Amyloid Beta Peptide: Implications for Exosome-Based Antioxidant Strategies
2019
The distribution of amyloid beta peptide 42 (Aβ42) between model exosomal membranes and a buffer solution was measured. The model membranes contained liquid-ordered regions or phosphatidylserine. Results demonstrated that up to ca. 20% of amyloid peptide, generated in the plasma (or intracellular) membrane as a result of proteolytic cleavage of amyloid precursor proteins by β- and γ-secretases, can stay within the membrane milieu. The selection of RNA aptamers that bind to Aβ42 incorporated into phosphatidylserine-containing liposomal membranes was performed using the selection-amplification (SELEX) method. After eight selection cycles, the pool of RNA aptamers was isol…
ODS tērauda izejmateriālu lokālās struktūras analīze izmantojot Ti un Y K-malas rentgenabsorbcijas spektroskopiju
2017
Šajā darbā tika izmantota rentgenstaru absorbcijas spektru analīze oksīdu stiprinātam tēraudam (ODS), kas ir perspektīvs materiāls dažādās jomās, piemēram, saules elektrostacijās, reaktīvos dzinējos, ķīmiskos reaktoros un kodolreaktoros, jo materiālam piemīt tādas īpašības kā laba siltumvadītspēja un zema termiskās izplešanās apvienojumā ar augstu temperatūras izturību, korozijas un radiācijas pretestību. Darbā tiek iegūta informācija par ar dažādām metodēm izgatavotu ODS tēraudu lokālās atomārās struktūras izmaiņu ap itrija (Y) un titāna (Ti) atomiem, analizējot Y un Ti absorbcijas K-malu.
In-beam γ-ray spectroscopy of low- and medium-spin levels in 211Po
2017
The structure of the low- and medium-spin levels of the 211Po nucleus have been studied with in-beam γ-ray spectroscopy with the 208Pb(α,n)211Po fusion-evaporation reaction. The level scheme was further extended with levels of the configurations π(h9/2)22+−4+⊗νg9/2, π(h9/2)28+⊗νg9/2, π(h9/2)22+−4+⊗νi11/2, π(h9/2)22+−4+⊗νj15/2, π(h9/2f7/2)8+⊗νg9/2, and π(h9/2)20+⊗ν(g9/2)20+(s1/2)−1. The single-particle neutron states νd5/2 and νs1/2 were also identified. Furthermore, a number of states feeding the low-spin structures were added. peerReviewed
Separation of atomic and molecular ions by ion mobility with an RF carpet
2021
Gas-filled stopping cells are used at accelerator laboratories for the thermalization of high-energy radioactive ion beams. Common challenges of many stopping cells are a high molecular background of extracted ions and limitations of extraction efficiency due to space-charge effects. At the FRS Ion Catcher at GSI, a new technique for removal of ionized molecules prior to their extraction out of the stopping cell has been developed. This technique utilizes the RF carpet for the separation of atomic ions from molecular contaminant ions through their difference in ion mobility. Results from the successful implementation and test during an experiment with a 600~MeV/u $^{124}$Xe primary beam are…
When the Grafting of Double Decker Phthalocyanines on Si(100)-2 × 1 Partly Affects the Molecular Electronic Structure
2016
International audience; A combined X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and density functional theory (DFT) study has been performed to characterize the adsorbate interaction of lutetium biphthalocyanine (LuPc2) molecules on the Si(100)-2 × 1 surface. Large molecule–substrate adsorption energies are computed and are found to compete with the molecule–molecule interactions of the double decker molecules. A particularly good matching between STM images and computed ones confirms the deformation of the molecule upon the absorption process. The comparison between DFT calculations and XP spectra reveals that the electronic distribution in the two plateaus …
X-ray Fluorescence Spectroscopy applied to the study of three sicilian painted artworks
2009
This paper reports on three X-Ray Fluorescence (XRF) studies of ancient Sicilian painted materials: a 13th century canvas from Cerami (Enna, Italy), the Muqarnas wood ceiling of the 12th century Palatine Chapel (Palermo, Italy) and a delicate early 20th century viola d’amore, the property of the Conservatorio di Musica “Vincenzo Bellini” in Palermo. Information about the pigments and preparation layer mixtures used as well as inferences regarding various past painting techniques emerged from the interpretation of spectra and data analyses.
The Interaction Mechanism of Intrinsically Disordered PP2A Inhibitor Proteins ARPP-16 and ARPP-19 With PP2A
2021
Protein phosphatase 2A (PP2A) activity is critical for maintaining normal physiological cellular functions. PP2A is inhibited by endogenous inhibitor proteins in several pathological conditions including cancer. A PP2A inhibitor protein, ARPP-19, has recently been connected to several human cancer types. Accordingly, the knowledge about ARPP-19—PP2A inhibition mechanism is crucial for the understanding the disease development and the therapeutic targeting of ARPP-19—PP2A. Here, we show the first structural characterization of ARPP-19, and its splice variant ARPP-16 using NMR spectroscopy, and SAXS. The results reveal that both ARPP proteins are intrinsically disordered but contain transient…
Artificial cartilage bio-matrix formed of hyaluronic acid and Mg2+-polyphosphate.
2016
Here we show that inorganic polyphosphate (polyP), a polyanionic metabolic regulator consisting of multiple phosphate residues linked by energy-rich phosphoanhydride bonds, is present in the synovial fluid. In a biomimetic approach, to enhance cartilage synthesis and regeneration, we prepared amorphous polyP microparticles with Mg2+ as counterions. The particles were characterised by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) and Fourier transformed infrared spectroscopic (FTIR) analyses. Similar particles were obtained after addition of Mg2+ ions to a solution containing hyaluronic acid, as a major component of the synovial fluid, and soluble Na-polyP. The viscous paste-like ma…
Fragmentations and reactions of protonated O,O-dimethyl ethylphosphonate and some isotopomers produced by electrospray ionisation in an ion trap mass…
2008
Abstract The fragmentation behaviour of protonated O , O -dimethyl ethylphosphonate and its isotopomers deuterated in the α- and β-positions of the ethyl group and their fragment ions, particulary EtP(O)OMe + ( IV ), have been investigated both experimentally in an ion trap mass spectrometer and theoretically by electronic structure calculations at the B3LYP level. Of particular interest is the finding that the phosphonium ion IV eliminates ethene with hydrogen/deuterium loss from both the α-and β-positions. The initial step for both routes involves ethyl migration from P to O to form the ion MeOP + OEt which then loses ethene by two mechanisms, both of which lead to the same products. That…
High-precision mass measurements for the isobaric multiplet mass equation atA= 52
2017
Masses of $^{52}$Co, $^{52}$Co$^m$, $^{52}$Fe, $^{52}$Fe$^m$, and $^{52}$Mn have been measured with the JYFLTRAP double Penning trap mass spectrometer. Of these, $^{52}$Co and $^{52}$Co$^m$ have been experimentally determined for the first time and found to be more bound than predicted by extrapolations. The isobaric multiplet mass equation for the $T=2$ quintet at $A=52$ has been studied employing the new mass values. No significant breakdown (beyond the $3\sigma$ level) of the quadratic form of the IMME was observed ($\chi^2/n=2.4$). The cubic coefficient was 6.0(32) keV ($\chi^2/n=1.1$). The excitation energies for the isomer and the $T=2$ isobaric analogue state in $^{52}$Co have been d…