scholarly journals XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4635
Author(s):  
Oleg V. Konovalov ◽  
Natalia N. Novikova ◽  
Mikhail V. Kovalchuk ◽  
Galina E. Yalovega ◽  
Alexey F. Topunov ◽  
...  
Keyword(s):  
Metal Binding ◽  
Radiation Condition ◽  
Liquid Interfaces ◽  
Radiation Load ◽  
Edge Structure ◽  
Site Structure ◽  
X Ray ◽  
Zinc Coordination ◽  
First Time ◽  
X Ray Absorption

X-ray absorption near edge structure (XANES) spectra for protein layers adsorbed at liquid interfaces in a Langmuir trough have been recorded for the first time. We studied the parkin protein (so-called E3 ubiquitin ligase), which plays an important role in pathogenesis of Parkinson disease. Parkin contains eight Zn binding sites, consisting of cysteine and histidine residues in a tetracoordinated geometry. Zn K-edge XANES spectra were collected in the following two series: under mild radiation condition of measurements (short exposition time) and with high X-ray radiation load. XANES fingerprint analysis was applied to obtain information on ligand environments around zinc ions. Two types of zinc coordination geometry were identified depending on X-ray radiation load. We found that, under mild conditions, local zinc environment in our parkin preparations was very similar to that identified in hemoglobin, treated with a solution of ZnCl2 salt. Under high X-ray radiation load, considerable changes in the zinc site structure were observed; local zinc environment appeared to be almost identical to that defined in Zn-containing enzyme alkaline phosphatase. The formation of a similar metal site in unrelated protein molecules, observed in our experiments, highlights the significance of metal binding templates as essential structural modules in protein macromolecules.

scholarly journals Local and electronic structure around Ga in CdTe: evidence of DX- and A-centers

2012 ◽  
Vol 20 (1) ◽  
pp. 166-171
Author(s):  
Vasil Koteski ◽  
Jelena Belošević-Čavor ◽  
Petro Fochuk ◽  
Heinz-Eberhard Mahnke
Keyword(s):  
Density Functional ◽  
Plane Waves ◽  
Lattice Relaxation ◽  
Defect Structures ◽  
Functional Theory ◽  
Edge Structure ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Good Agreement

The lattice relaxation around Ga in CdTe is investigated by means of extended X-ray absorption spectroscopy (EXAFS) and density functional theory (DFT) calculations using the linear augmented plane waves plus local orbitals (LAPW+lo) method. In addition to the substitutional position, the calculations are performed for DX- and A-centers of Ga in CdTe. The results of the calculations are in good agreement with the experimental data, as obtained from EXAFS and X-ray absorption near-edge structure (XANES). They allow the experimental identification of several defect structures in CdTe. In particular, direct experimental evidence for the existence of DX-centers in CdTe is provided, and for the first time the local bond lengths of this defect are measured directly.

Delocalized versus localized unoccupied5fstates and the uranium site structure in uranium oxides and glasses probed by x-ray-absorption near-edge structure

1986 ◽  
Vol 34 (10) ◽  
pp. 7350-7361 ◽  
Author(s):  
J. Petiau ◽  
G. Calas ◽  
D. Petitmaire ◽  
A. Bianconi ◽  
M. Benfatto ◽  
...  
Keyword(s):  
Uranium Oxides ◽  
Edge Structure ◽  
Site Structure ◽  
X Ray ◽  
X Ray Absorption

High-accuracy X-ray absorption spectra from mMsolutions of nickel (II) complexes with multiple solutions using transmission XAS

2015 ◽  
Vol 22 (4) ◽  
pp. 1008-1021 ◽  
Author(s):  
Christopher T. Chantler ◽  
M. Tauhidul Islam ◽  
Stephen P. Best ◽  
Lachlan J. Tantau ◽  
Chanh Q. Tran ◽  
...  
Keyword(s):  
Multiple Solutions ◽  
High Accuracy ◽  
Hybrid Technique ◽  
Edge Structure ◽  
New Approach ◽  
X Ray ◽  
Square Planar ◽  
Transmission Measurements ◽  
First Time ◽  
X Ray Absorption

A new approach is introduced for determining X-ray absorption spectroscopy (XAS) spectra on absolute and relative scales using multiple solutions with different concentrations by the characterization and correction of experimental systematics. This hybrid technique is a development of standard X-ray absorption fine structure (XAFS) along the lines of the high-accuracy X-ray extended range technique (XERT) but with applicability to solutions, dilute systems and cold cell environments. This methodology has been applied to determining absolute XAS of bis(N-n-propyl-salicylaldiminato) nickel(II) and bis(N-i-propyl-salicylaldiminato) nickel(II) complexes with square planar and tetrahedral structures in 15 mMand 1.5 mMdilute solutions. It is demonstrated that transmission XAS from dilute systems can provide excellent X-ray absorption near-edge structure (XANES) and XAFS spectra, and that transmission measurements can provide accurate measurement of subtle differences including coordination geometries. For the first time, (transmission) XAS of the isomers have been determined from low-concentration solutions on an absolute scale with a 1–5% accuracy, and with relative precision of 0.1% to 0.2% in the active XANES and XAFS regions after inclusion of systematic corrections.

scholarly journals Local Fe site structure in the tense-to-relaxed transition in carp deoxyhemoglobin: a XANES (x-ray absorption near edge structure) study.

1986 ◽  
Vol 83 (20) ◽  
pp. 7736-7740 ◽  
Author(s):  
A. Bianconi ◽  
A. Congiu-Castellano ◽  
M. Dell'Ariccia ◽  
A. Giovannelli ◽  
S. Morante ◽  
...  
Keyword(s):  
Structure Study ◽  
Edge Structure ◽  
Site Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals An extended-X-ray-absorption-fine-structure study of freeze-dried and solution ovotransferrin. Evidence for water co-ordination at the metal-binding sites

1987 ◽  
Vol 247 (2) ◽  
pp. 369-375 ◽  
Author(s):  
S S Hasnain ◽  
R W Evans ◽  
R C Garratt ◽  
P F Lindley
Keyword(s):  
Fine Structure ◽  
Metal Binding ◽  
Binding Sites ◽  
Structure Study ◽  
Humid Atmosphere ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Freeze Dried ◽  
X Ray Absorption

Our previous extended-X-ray-absorption-fine-structure (e.x.a.f.s.) study has shown that the probable iron environment in chicken ovotransferrin involves two low-Z ligands (consistent with phenolate linkages) at 0.185(1) nm and four low-Z ligands at 0.204(1) nm [Garratt, Evans, Hasnain & Lindley (1986) Biochem. J. 233, 479-484]. Herein we provide additional information from the e.x.a.f.s. and near-edge structure suggestive of a decrease in the co-ordination number of ovotransferrin-bound iron upon freeze-drying. These effects are reversible, and exposure of the freeze-dried material to a humid atmosphere results in reversion to the solution spectra. Progressive rehydration was monitored by using e.p.r. spectroscopy and was confirmed by recording the high-resolution X-ray-absorption near-edge structure (x.a.n.e.s.). The results suggest the presence of a labile water molecule at the iron-binding sites of ovotransferrin in solution.

Mo coordination and Thermal Stability of the Mo–Si3N4 Absorbers for Solar Selective Coatings

MRS Advances ◽  
2017 ◽  
Vol 2 (53) ◽  
pp. 3061-3068 ◽  
Author(s):  
C. Prieto ◽  
E. Céspedes ◽  
D. Hernández-Pinilla ◽  
A. Rodríguez-Palomo ◽  
O. Sánchez ◽  
...  
Keyword(s):  
Concentrated Solar Power ◽  
Edge Structure ◽  
X Ray ◽  
Practical Applications ◽  
Design And Optimization ◽  
Structural Correlation ◽  
First Time ◽  
X Ray Absorption ◽  
Optical Behavior ◽  
Thermal Stability Of

ABSTRACTThe study of the chemical stability of solar selective coatings (SSC) for concentrated solar power (CSP) becomes essential for their use at high temperatures. In this paper, the short range order around Mo in Mo-Si3N4 cermets is studied for the first time by X-ray absorption spectroscopy. The information obtained by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopies gives new insights of the origin of the optical behavior of the cermets cermets after vacuum and air annealing treatments. The established optical and structural correlation becomes of great importance for the design and optimization of SSC for practical applications.

Interplay between Local Electronic Structure, Crystalline Structure and Magnetic Ordering in Intermetallic Compounds Ce2Fe17−xMnx

2012 ◽  
Vol 190 ◽  
pp. 251-254 ◽  
Author(s):  
Alexander A. Yaroslavtsev ◽  
Alexey P. Menushenkov ◽  
Olga V. Grishina ◽  
Roman V. Chernikov ◽  
Anatoly G. Kuchin
Keyword(s):  
Crystalline Structure ◽  
Magnetic Ordering ◽  
Local Environment ◽  
Edge Structure ◽  
X Ray ◽  
Local Electronic Structure ◽  
Magnetic States ◽  
First Time ◽  
X Ray Absorption ◽  
Mn Concentration

For the first time the rearrangement of cerium local environment in Ce2Fe17-xMnx(x = 0; 1; 2) intermetallics vs. Mn concentration and temperature was investigated by thespectroscopy of extended X-ray absorption fine structure (EXAFS) above K-Ce absorptionedge. At the same time under similar conditions by the spectroscopy of X-ray absorption near-edge structure (XANES) above L3-Ce absorption edge the valence state of Ce was studied. Thecorrelation is found between changes in local electronic and crystalline structure observed inCe2Fe17-xMnx and the types of magnetic states in these compounds.

scholarly journals In situ X-ray absorption near edge structure studies and charge transfer kinetics of Na6[V10O28] electrodes

2017 ◽  
Vol 19 (4) ◽  
pp. 3358-3365 ◽  
Author(s):  
Han-Yi Chen ◽  
Jochen Friedl ◽  
Chun-Jern Pan ◽  
Ali Haider ◽  
Rami Al-Oweini ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Absorption Spectroscopy ◽  
Edge Structure ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Kinetics Of

The electron transfer of Na6[V10O28] was investigated byin situV K-edge X-ray absorption spectroscopy and chronoamperometric experiments for the first time.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

In Vivo Investigation of the Distribution and the Local Speciation of Selenium inAlliumcepa L. by Means of Microscopic X-ray Absorption Near-Edge Structure Spectroscopy and Confocal Microscopic X-ray Fluorescence Analysis

2006 ◽  
Vol 78 (22) ◽  
pp. 7616-7624 ◽  
Author(s):  
Ewa Bulska ◽  
Irena A. Wysocka ◽  
Małgorzata H. Wierzbicka ◽  
Kristof Proost ◽  
Koen Janssens ◽  
...  
Keyword(s):  
Fluorescence Analysis ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption
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