Extraction and use of correlated integrated intensities with powder diffraction data

Wright, J.P.

doi:10.1524/zkri.219.12.791.55857

Cited by 31 publications

(16 citation statements)

References 18 publications

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“…The intensities of the reflections within one overlap group can be set to be equal (equipartitioned) or can be estimated by a more elaborate techni- (FIPS, Estermann and Gramlich, 1993). It is also possible to use intensities gleaned from more sophisticated data collections that exploit texture or anisotropic thermal expansion (Wright, 2004) to get better estimates of the overlapping intensities. Then only those overlapping reflections whose intensities are not resolved are flagged.…”

Section: Accommodating Powder Diffraction Datamentioning

confidence: 99%

Charge flipping combined with histogram matching to solve complex crystal structures from powder diffraction data

Baerlocher¹,

McCusker²,

Palatinus³

2007

Zeitschrift Für Kristallographie

131

107

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Abstract. The charge-flipping structure-solution algorithm introduced by Oszlányi and Sütő in 2004 has been adapted to accommodate powder diffraction data. In particular, a routine for repartitioning the intensities of overlapping reflections has been implemented within the iterative procedure. This is done by modifiying the electron density map with a histogram-matching algorithm, and then using the Fourier coefficients obtained from this map to repartition the structure factor amplitudes within each overlap group. The effectiveness of the algorithm has been demonstrated with five test examples covering different classes of materials of varying complexity ]), cimetidine (C 10

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Section: Accommodating Powder Diffraction Datamentioning

confidence: 99%

Charge flipping combined with histogram matching to solve complex crystal structures from powder diffraction data

Baerlocher¹,

McCusker²,

Palatinus³

2007

Zeitschrift Für Kristallographie

131

107

View full text Add to dashboard Cite

show abstract

“…A material that exhibits anisotropic thermal expansion, for example, can be measured at several different temperatures and the changes in the overlap pattern caused by changes in the lattice parameters exploited to obtain better estimates of the individual reflection intensities [3][4][5]. Alternatively, a sample with a preferred orientation of the crystallites, which will yield a diffraction pattern whose intensities are dependent upon the orientation of the sample in the X-ray beam, can be used.…”

Section: Introductionmentioning

confidence: 99%

“…In an attempt to reduce the amount of beamtime required and to eliminate the need for a large homogeneous sample, the method was adapted to work with data collected in transmission mode using a small sample and a 2-dimensional detector [12]. Cerny used a similar setup to investigate SmCo 5 and TbCo 5 , which had been oriented along a single direction using a magnetic field [13].…”

Section: Introductionmentioning

confidence: 99%

Exploiting texture to estimate the relative intensities of overlapping reflections

Baerlocher¹,

McCusker²,

Prokic³

et al. 2004

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract. Additional information about the relative intensities of reflections that overlap in a powder diffraction pattern can be obtained from a polycrystalline sample in which the crystallites are preferentially oriented. If the data are collected and analyzed appropriately, more single-crystal-like reflection intensities can be extracted, and thereby more complex structures solved. This 'texture method' was implemented initially in reflection mode and its power demonstrated with the solution of the 117-atom structure of the high-silica zeolite UTD-1F. However, the experiment required a minimum of 3 days of synchrotron beamtime per sample. In an attempt to reduce the amount of beamtime needed and to simplify the experiment itself, a transmission mode alternative using an area detector was developed. Details of the sample preparation, data collection and data analysis for both geometries are described. The solution of the structures of the aluminophosphates Mu-9 (R 3 3c, a ¼ 14.0696(1) A, c ¼ 42.3113(4) A) and AlPO-M (Pbca, a ¼ 9.7493(1) A, b ¼ 29.1668(2) A, c ¼ 9.3528(1) A) using reflection and transmission mode data, respectively, are provided as examples of the method.

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“…Considering the fact that XRPD data are characterized by peak overlap, combining multiple data sets together where either the cell parameters or the preferred orientation is different allows the contributing reflections within a cluster of overlapped peaks to be more easily distinguished. The PRODD refinement program [23,85,86] has been modified to allow a multi-pattern Pawley fit [75] leading to more accurate intensity extraction.…”

Section: Protein Structure Solution Via Xrpdmentioning

confidence: 99%

Applications of X-ray Powder Diffraction in Protein Crystallography and Drug Screening

et al. 2020

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Providing fundamental information on intra/intermolecular interactions and physicochemical properties, the three-dimensional structural characterization of biological macromolecules is of extreme importance towards understanding their mechanism of action. Among other methods, X-ray powder diffraction (XRPD) has proved its applicability and efficiency in numerous studies of different materials. Owing to recent methodological advances, this method is now considered a respectable tool for identifying macromolecular phase transitions, quantitative analysis, and determining structural modifications of samples ranging from small organics to full-length proteins. An overview of the XRPD applications and recent improvements related to the study of challenging macromolecules and peptides toward structure-based drug design is discussed. This review congregates recent studies in the field of drug formulation and delivery processes, as well as in polymorph identification and the effect of ligands and environmental conditions upon crystal characteristics. These studies further manifest the efficiency of protein XRPD for quick and accurate preliminary structural characterization.

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Extraction and use of correlated integrated intensities with powder diffraction data

Cited by 31 publications

References 18 publications

Charge flipping combined with histogram matching to solve complex crystal structures from powder diffraction data

Charge flipping combined with histogram matching to solve complex crystal structures from powder diffraction data

Exploiting texture to estimate the relative intensities of overlapping reflections

Applications of X-ray Powder Diffraction in Protein Crystallography and Drug Screening

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