Characterization of Athabasca and Arabian Light Vacuum Residues and Their Thermally Cracked Products: Implications of the Structural Information on Adsorption over Solid Surfaces

2015 ◽  
pp. 84-103
Keyword(s):  
Structural Information ◽  
Solid Surfaces

Structural Characterization of Complex Bacterial Glycolipids by Fourier Transform Mass Spectrometry

2005 ◽  
Vol 11 (5) ◽  
pp. 535-546 ◽  
Author(s):  
Anna Kondakov ◽  
Buko Lindner
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Structural Information ◽  
Adaptive Immune System ◽  
Ion Cyclotron Resonance ◽  
Bacterial Membranes ◽  
Multiphoton Dissociation ◽  
The One ◽  
And Function

Bacterial glycolipids are complex amphiphilic molecules which are, on the one hand, of utmost importance for the organization and function of bacterial membranes and which, on the other hand, play a major role in the activation of cells of the innate and adaptive immune system of the host. Already small alterations to their chemical structure may influence the biological activity tremendously. Due to their intrinsic biological heterogeneity [number and type of fatty acids, saccharide structures and substitution with for example, phosphate ( P), 2-aminoethyl-(pyro)phosphate groups ( P-Etn) or 4-amino-4-deoxyarabinose (Ara4N)], separation of the different components are a prerequisite for unequivocal chemical and nuclear magnetic resonance structural analyses. In this contribution, the structural information which can be obtained from heterogenous samples of glycolipids by Fourier transform (FT) ion cyclotron resonance mass spectrometric methods is described. By means of recently analysed complex biological samples, the possibilities of high-resolution electrospray ionization FT-MS are demonstrated. Capillary skimmer dissociation, as well as tandem mass spectrometry (MS/MS) analysis utilizing collision-induced dissociation and infrared multiphoton dissociation, are compared and their advantages in providing structural information of diagnostic importance are discussed.

Micro-Scale Flow Simulations and Permeability Estimation of Cleat Networks in Coal

2016 ◽  
Vol 846 ◽  
pp. 42-47
Author(s):  
J. Busse ◽  
S. Galindo Torres ◽  
Alexander Scheuermann ◽  
L. Li ◽  
D. Bringemeier
Keyword(s):  
Gas Flow ◽  
Structural Information ◽  
Porous Matrix ◽  
Groundwater Levels ◽  
Micro Scale ◽  
Wide Range ◽  
Boltzmann Method ◽  
The Impact ◽  
Flow Experiments

Coal mining raises a number of environmental and operational challenges, including the impact of changing groundwater levels and flow patterns on adjacent aquifer and surface water systems. Therefore it is of paramount importance to fully understand the flow of water and gases in the geological system on all scales. Flow in coal seams takes place on a wide range of scales from large faults and fractures to the micro-structure of a porous matrix intersected by a characteristic cleat network. On the micro-scale these cleats provide the principal source of permeability for fluid and gas flow. Description of the behaviour of the flow within the network is challenging due to the variations in number, sizing, orientation, aperture and connectivity at a given site. This paper presents a methodology to simulate flow and investigate the permeability of fractured media. A profound characterization of the geometry of the cleat network in micrometer resolution can be derived by CT-scans. The structural information is fed into a Lattice Boltzmann Method (LBM) based model that allows the implementation of virtual flow experiments. With the application of suitable hydraulic boundary conditions the full permeability tensor can be calculated in 3D.

Preparation and Characterization of Stable Molecular Glasses of Europium(III) Acyl-Alaninate Complexes

2018 ◽  
Vol 271 ◽  
pp. 34-39 ◽  
Author(s):  
Naren Gerile ◽  
H. Alata ◽  
Tian Xiao ◽  
Ta Na Bao ◽  
Ojin Tegus
Keyword(s):  
Structural Information ◽  
Glassy State ◽  
Europium Complexes ◽  
Molecular Glasses ◽  
Xrd Diffraction ◽  
Polarizing Microscope ◽  
Chemical Reaction Method ◽  
The Eu ◽  
Eu Complexes

Working with acylaminocarboxylate ligands, we used ethanol and water as a solvent, and the europium complexes were prepared using a chemical reaction method in solution. The elements were analyzed and characterized by polarizing microscope and XRD, respectively. The surfaces of complexes in the solid state were observed by polarizing microscope morphology. XRD diffraction data confirms the periodic long range order/disorder structure of these europium complexes. We also found that diversified material was easily formed by the rare earth complexes. Using the above tests, the structural information of the Eu complexes in the glassy state, liquid crystal glassy state and crystalline states was obtained

scholarly journals Atomic-level characterization of protein–protein association

2019 ◽  
Vol 116 (10) ◽  
pp. 4244-4249 ◽  
Author(s):  
Albert C. Pan ◽  
Daniel Jacobson ◽  
Konstantin Yatsenko ◽  
Duluxan Sritharan ◽  
Thomas M. Weinreich ◽  
...  
Keyword(s):  
Structural Information ◽  
Protein Complexes ◽  
Md Simulations ◽  
Atomic Level ◽  
Conformational Ensemble ◽  
Native State ◽  
Protein Interfaces ◽  
Study Association ◽  
Functionally Diverse

Despite the biological importance of protein–protein complexes, determining their structures and association mechanisms remains an outstanding challenge. Here, we report the results of atomic-level simulations in which we observed five protein–protein pairs repeatedly associate to, and dissociate from, their experimentally determined native complexes using a molecular dynamics (MD)–based sampling approach that does not make use of any prior structural information about the complexes. To study association mechanisms, we performed additional, conventional MD simulations, in which we observed numerous spontaneous association events. A shared feature of native association for these five structurally and functionally diverse protein systems was that if the proteins made contact far from the native interface, the native state was reached by dissociation and eventual reassociation near the native interface, rather than by extensive interfacial exploration while the proteins remained in contact. At the transition state (the conformational ensemble from which association to the native complex and dissociation are equally likely), the protein–protein interfaces were still highly hydrated, and no more than 20% of native contacts had formed.

C60 Framework Response to Halogen Addition: the Stable Isomers of C60Br2m

1994 ◽  
Vol 47 (1) ◽  
pp. 131 ◽  
Author(s):  
JB Peel ◽  
RG Rothwell
Keyword(s):  
Double Bond ◽  
Molecular Orbital ◽  
High Stability ◽  
Structural Information ◽  
Spectroscopic Characterization ◽  
The Other ◽  
Semiempirical Calculations ◽  
Elementary Model ◽  
Local Distortion

The isolation and spectroscopic characterization of halogenated fullerene-60 compounds has not advanced greatly during the 2 years of effort in this area. While the fully fluorinated C60F60 has been studied in some detail, other halogen addition processes have indicated chlorination up to C60Cl24 and bromination up to C60Br24. However, definitive structural information has to date only been provided for three compounds, namely C60Br6, C60Br6 and C60Br24. Iodine does not appear to form genuine addition compounds. In the work reported here semiempirical calculations using the AM1 approximation with the MOPAC molecular orbital program have been directed to comparing the possible stable isomers of the 1:1 addition compounds C60X2 for X = F, Cl and Br. The favoured isomers can be described as 1,2-additions (to a double bond at a hexagon-hexagon fusion) and 1,4-additions (to the terminal carbons of a butadiene moiety) with higher-energy isomers resulting from 1,6- and 1,8-additions. The other isomers represented by 1,3- 1,5- and 1,7-additions are only stable relative to dissociation in the case of the fluorine addition compounds. By contrast for Br2 addition only the 1,2- and 1,4-isomers are stable toward dissociation. The calculations show that, at and near the addition site carbons, X2 addition is adequately described in terms of local distortion of the C60 sphere. The elementary model of C60 as comprising formal single and double bonds is relevant since C60 behaves as a 'poly- alkene ', with sp3 carbons replacing sp2 carbons at the addition sites. This model offers an explanation for the unique structures observed for C60Br6 and C60Br24 which the AM1calculations show to be very stable toward dissociation. However, the experimental C60Br8 structure is found to be relatively less stable than another isomer. Also high-stability isomers of C60Br4, C60Br10, C60Br12 and C60Br18 are predicted.

scholarly journals Extracting structural information of Au colloids at ultra-dilute concentrations: identification of growth during nanoparticle immobilization

2019 ◽  
Vol 1 (7) ◽  
pp. 2546-2552 ◽  
Author(s):  
George F. Tierney ◽  
Donato Decarolis ◽  
Norli Abdullah ◽  
Scott M. Rogers ◽  
Shusaku Hayama ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Structural Characterization ◽  
Structural Information ◽  
Particle Growth ◽  
Au Nanoparticle ◽  
X Ray ◽  
Colloidal Au ◽  
X Ray Absorption ◽  
Au Colloids

This paper describes the structural characterization of ultra-dilute colloidal Au nanoparticle solutions using X-ray absorption spectroscopy (XAS) and the particle growth during immobilization.

A Reactor for “Ex-Situ” TEM Catalyst Characterization

1999 ◽  
Vol 5 (S2) ◽  
pp. 926-927 ◽  
Author(s):  
C.E. Kliewer ◽  
M.M. Disko ◽  
S.L Soled ◽  
G.J. DeMartin
Keyword(s):  
Catalytic Properties ◽  
Structural Information ◽  
High Vacuum ◽  
Chemical Characterization ◽  
Ex Situ ◽  
Catalyst Characterization ◽  
Initial Development ◽  
Transmission Electron ◽  
Pressure Variable

The microstructural and chemical characterization of catalysts is not only integral to their initial development but also to understanding and controlling their behavior over time. To better elucidate the morphology of these materials and relate physical properties to catalytic properties (e.g., activity, selectivity, etc.), “ex-situ” methods for studying catalysts under reactive conditions have been developed.Because conventional transmission electron microscopy (CTEM) is conducted under high vacuum conditions, it is difficult to replicate the exact chemical environment of a catalyst (e.g., high pressure, variable gas mixtures, etc) within the TEM. Consequently, most analyses focus on comparing “fresh” and “spent” materials. In general, this methodology provides useful structural information albeit with limitations associated with the comparison of dissimilar regions and the effects of sampling inhomogenieties.

scholarly journals Development of FTIR Spectroscopy Methodology for Characterization of Boron Species in FCC Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1327 ◽  
Author(s):  
Claire Chunjuan Zhang ◽  
Xingtao Gao ◽  
Bilge Yilmaz
Keyword(s):  
Structural Information ◽  
Glass Ceramics ◽  
Boron Trioxide ◽  
Fcc Catalyst ◽  
Ftir Characterization ◽  
Wide Range ◽  
The World ◽  
Contaminant Metals ◽  
Fcc Catalysts

Fluid Catalytic Cracking (FCC) has maintained its crucial role in refining decades after its initial introduction owing to the flexibility it has as a process as well as the developments in its key enabler, the FCC catalyst. Boron-based technology (BBT) for passivation of contaminant metals in FCC catalysts represents one such development. In this contribution we describe Fourier Transform Infrared Spectroscopy (FTIR) characterization of boron-containing catalysts to identify the phase and structural information of boron. We demonstrate that FTIR can serve as a sensitive method to differentiate boron trioxide and borate structures with a detection limit at the 1000 ppm level. The FTIR analysis validates that the boron in the FCC catalysts studied are in the form of small borate units and confirms that the final FCC catalyst product contains no detectable isolated boron trioxide phase. Since boron trioxide is regulated in some parts of the world, this novel FTIR methodology can be highly beneficial for further FCC catalyst development and its industrial application at refineries around the world. This new method can also be applied on systems beyond catalysts, since the characterization of boron-containing materials is needed for a wide range of other applications in the fields of glass, ceramics, semiconductors, agriculture, and pharmaceuticals.

Understanding the structure details when drying hydrate crystals of pharmaceuticals – interpretations from diffuse scattering and inter-modulation satellites of a partially dehydrated crystal

2014 ◽  
Vol 70 (3) ◽  
pp. 555-567 ◽  
Author(s):  
E. J. Chan ◽  
Q. Gao ◽  
M. Dabros
Keyword(s):  
Large Scale ◽  
Structural Information ◽  
Layer Structure ◽  
Modulated Structure ◽  
Drying Procedures ◽  
Pure Phase ◽  
Disordered Layer ◽  
Transitory Phase ◽  
Lower Water Content

Simplified models for the crystal lattice of the sesquihydrate form of the hemi-sulfate salt of (5S,6S,9R)-5-amino-6-(2,3-difluorophenyl)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-9-yl 4-(2-oxo-2,3-dihydro-1H-imidazol[4,5b]pyridin-1-yl)-1-piperidine carboxylate (BMS-927711, C28H29F2N6O3+) are used to calculate diffuse diffraction features in order to develop a mechanistic understanding of the dehydration process with respect to disruption of the lattice, since a Bragg model cannot be established. The model demonstrates that what we observe when the water leaves the crystal is partial transformation from the parent form to a child form (a new form, less hydrated and structurally related to the parent). Yet this `dried' structure is not a pure phase. It consists of semi-random layers of both child, parent and an interfacial layer which has a modulated structure that represents a transitory phase. Understanding the fact that a single `dried' crystal can have the disordered layer structure described as well as understanding mechanistic relationships between the phases involved can have implications in understanding the effect of common large scale bulk drying procedures. During the development of BMS-927711, difficulties did arise during characterization of the dried bulk when using only routine solid-state analysis. The material is now better understood from this diffraction study. The diffraction experiments also reveal intermodulation satellites, which upon interpretation yield even more structural information about the crystal transformation. The model suggests the mechanism of transformation is laminar in which layers of the crystal are driven to approach a stableB-centered supercell phase of lower water content.

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