Low-Angle X-Ray Diffraction and Electron-Microscope Studies of Isolated Cell Membranes

1966 ◽  
Vol 1 (3) ◽  
pp. 287-296
Author(s):  
J. B. FINEAN ◽  
R. COLEMAN ◽  
W. G. GREEN ◽  
A. R. LIMBRICK
Keyword(s):  
Diffraction Pattern ◽  
Close Packing ◽  
Hexagonal Structure ◽  
Erythrocyte Membranes ◽  
Multiphase System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Guinea Pig Brain ◽  
Isolated Cell

A sequence of low-angle X-ray diffraction patterns obtained during the controlled drying of a preparation of rat erythrocyte ghosts has been interpreted with the aid of corresponding electron micrographs and of a parallel study of myelin isolated from guinea-pig brain. A diffraction pattern that persists down to a level of 10-20% hydration of the sample is believed to arise from the close packing of native erythrocyte membranes. Each membrane is about 100 Å thick and it is suggested that it consists of a predominantly continuous bimolecular layer of lipid, with non-lipid components associated with both surfaces. Further changes in diffraction pattern which accompany continued drying could be interpreted either as a change from a lamellar to a hexagonal structure or as the formation of a multiphase system. Evidence is put forward to support the latter interpretation.

Low-Angle X-Ray Diffraction and Electron-Microscope Studies of Isolated Erythrocyte Membranes

1970 ◽  
Vol 7 (2) ◽  
pp. 357-371
Author(s):  
S. KNUTTON ◽  
J. B. FINEAN ◽  
R. COLEMAN ◽  
A. R. LIMBRICK
Keyword(s):  
Erythrocyte Membranes ◽  
Multiphase System ◽  
Type I ◽  
Type Ii ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Differences ◽  
Diffraction Patterns ◽  
Haemoglobin Content ◽  
Human Erythrocyte Ghost

Two alternative sequences of low angle X-ray diffraction patterns (Type I and Type II) have been observed during the controlled dehydration of rat (and human) erythrocyte ghost preparations in which the residual haemoglobin content has varied. The Type I sequence has been obtained when haemoglobin has comprised more than 30% of the total protein of the membrane preparation. It features an initial lamellar pattern that has been interpreted in terms of a predominantly continuous lipoprotein sandwich structure. Subsequent changes in diffraction pattern have been suggested to represent a partial breakdown of the lipoprotein structure to give a multiphase system. The Type II sequence was most readily obtained from haemoglobin-free ghosts. At no stage during the dehydration of these ghosts did the diffraction feature a stable lamellar pattern. At all levels of hydration the X-ray reflections appeared to represent independent lipid and lipoprotein phases. Osmium tetroxide fixation of haemoglobin-free membranes prevented the separation of lipid and lipoprotein phases during dehydration. Comparisons of electron micrographs of condensed membrane preparations have revealed some structural differences between membranes which give rise to the Type I and Type II diffraction sequences.

scholarly journals The 3D structure of fibrous material is fully restorable from its X-ray diffraction pattern

IUCrJ ◽  
2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Hiroyuki Iwamoto
Keyword(s):  
Diffraction Pattern ◽  
Fibrous Material ◽  
3D Structure ◽  
Wide Field ◽  
Fibrous Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fiber Diffraction ◽  
Puzzle Solving ◽  
Diffraction Patterns

X-ray fiber diffraction is potentially a powerful technique to study the structure of fibrous materials, such as DNA and synthetic polymers. However, only rotationally averaged diffraction patterns can be recorded and it is difficult to correctly interpret them without the knowledge of esoteric diffraction theories. Here we demonstrate that, in principle, the non-rotationally averaged 3D structure of a fibrous material can be restored from its fiber diffraction pattern. The method is a simple puzzle-solving process and in ideal cases it does not require any prior knowledge about the structure, such as helical symmetry. We believe that the proposed method has a potential to transform the fiber diffraction to a 3D imaging technique, and will be useful for a wide field of life and materials sciences.

The X-Ray Powder Diffraction Patterns and Crystal Structure for Al2M3Y(M=Cu, Ni)

2014 ◽  
Vol 950 ◽  
pp. 48-52
Author(s):  
De Gui Li ◽  
Ming Qin ◽  
Liu Qing Liang ◽  
Zhao Lu ◽  
Shu Hui Liu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Hexagonal Structure ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Arc Melting ◽  
Diffraction Patterns

The Al2M3Y(M=Cu, Ni) compound was synthesized by arc melting under argon atmosphere. The high-quality powder X-ray diffraction data of Al2M3Y have been presented. The refinement of the X-ray diffraction patterns for the Al2M3Y compound show that the Al2M3Y has hexagonal structure, space groupP6/mmm(No.191), with a = b = 5.1618(2) Å, c = 4.1434(1) Å,V= 95.6 Å3,Z= 1,ڑx= 5.7922 g/cm3,F30= 155.5(0.0057, 34), RIR = 2.31 for Al2Cu3Y, and with a = b = 5.0399(1) Å, c = 4.0726(1) Å,V= 89.59 Å3,Z= 1,ڑx= 5.9118 g/cm3,F30= 135.7(0.0072, 30), RIR = 2.54 for Al2Ni3Y.

Electrochemical Deposition and Characterization of Cd-Fe-Se Thin Films

2009 ◽  
Vol 68 ◽  
pp. 69-76 ◽  
Author(s):  
S. Thanikaikarasan ◽  
T. Mahalingam ◽  
K. Sundaram ◽  
Tae Kyu Kim ◽  
Yong Deak Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Hexagonal Structure ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Selenide ◽  
Glass Substrates ◽  
Diffraction Patterns ◽  
Cadmium Iron Selenide ◽  
Deposited Films

Cadmium iron selenide (Cd-Fe-Se) thin films were deposited onto tin oxide (SnO2) coated conducting glass substrates from an aqueous electrolytic bath containing CdSO4, FeSO4 and SeO2 by potentiostatic electrodeposition. The deposition potentials of Cadmium (Cd), Iron (Fe), Selenium (Se) and Cadmium-Iron-Selenide (Cd-Fe-Se) were determined from linear cathodic polarization curves. The deposited films were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by x-rays (EDX) and optical absorption techniques, respectively. X-ray diffraction patterns shows that the deposited films are found to be hexagonal structure with preferential orientation along (100) plane. The effect of FeSO4 concentration on structural, morphological, compositional and optical properties of the films are studied and discussed in detail.

Powder X-Ray Data for Synthetic Anhydrous Sodium Zirconium Silicates

1987 ◽  
Vol 2 (3) ◽  
pp. 176-179 ◽  
Author(s):  
G. Wilson ◽  
F. P. Glasser
Keyword(s):  
Solid State ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
The Other ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Sodium Zirconium ◽  
Diffraction Patterns

AbstractA systematic survey of phase formation in the Na2O-ZrO2-SiO2 system has revealed inconsistencies in the number and identity of ternary phases, and of their X-ray powder data. The phases Na2ZrSiO5, Na4Zr2Si3O12, Na2ZrSi2O7 and Na2ZrSi4O11 were prepared by solid-state reaction and their experimental X-ray diffraction patterns measured. Calculated X-ray diffraction patterns were generated by computer, using published crystallographic data, and critically compared with the experimentally observed values. The unit-cell constants were redefined to a greater accuracy than the presently accepted values published in the Powder Diffraction File. Only Na4Zr2Si3O12 produced an X-ray diffraction pattern which agreed with that previously published; those from the other phases were significantly different in both the intensities and positions of the reflections. Data for synthetic Na2ZrSi4O11 identical to the mineral vlasovite are reported.

The Hinckley index for kaolinites

Clay Minerals ◽  
1988 ◽  
Vol 23 (3) ◽  
pp. 249-260 ◽  
Author(s):  
A. Plançon ◽  
R. F. Giese ◽  
R. Snyder
Keyword(s):  
Diffraction Pattern ◽  
Defect Structure ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linear Fashion ◽  
Non Linear ◽  
Diffraction Patterns ◽  
Good Agreement

AbstractThe (02,11) X-ray diffraction band from a low-defect kaolinite from Cornwall (Hinckley index HI = 1·22) was examined to determine the defect structure. No combination of interlayer translations and admixing of dickite layers accurately modelled the observed diffraction pattern. Calculated diffraction patterns which gave a good agreement with the shape, position, and intensity of the observed peaks, uniformly had inter-peak intensities which were too weak. By treating the kaolinite as a mixture of low-defect (HI = 1·76) and moderate-defect (HI = 0·29) kaolinites, the agreement between the observed and calculated patterns was improved substantially. The existence of a mixture of two kaolinites was also found for a number of low-defect samples (HI > 0·4) from Georgia and Cornwall, and may be of even wider occurrence. The HI, which is very sensitive to the inner-peak intensities, does not estimate the types or abundances of various structural defects (the classical “crystallinity”), but is related directly, in a non-linear fashion, to the proportions of the two kinds of kaolinite which are present in the sample.

Upsampling speckle patterns for coherent X-ray diffraction imaging

2013 ◽  
Vol 46 (2) ◽  
pp. 319-323 ◽  
Author(s):  
Y. Chushkin ◽  
F. Zontone
Keyword(s):  
Diffraction Pattern ◽  
Imaging Technique ◽  
Real Space ◽  
Field Of View ◽  
Combination Method ◽  
Pixel Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Imaging ◽  
Diffraction Patterns

Coherent X-ray diffraction imaging is a lensless imaging technique where an iterative phase-retrieval algorithm is applied to the speckle pattern, the far-field diffraction pattern produced by an isolated object. To ensure convergence to a unique solution, the diffraction pattern must be oversampled by a factor of two or more. Since the resolution in real space depends on the maximum wave vector where the intensity is detected,i.e.on the detector field of view, there is a practical limitation on oversampling in reciprocal space and resolution in real space that is ultimately determined by the number of pixels. This work shows that it is possible to reduce the effective pixel size and maintain the detector field of view by applying a linear combination method to shifted diffraction patterns. The feasibility of the method is demonstrated by reconstructing the images of test objects from diffraction patterns oversampled in each dimension by factors of 1.3 and 1.8 only. The described approach can be applied to any diffraction or imaging technique where the resolution is compromised by a large pixel size.

X-ray powder diffraction pattern and crystal structure of AlCu4Y ternary compound

2015 ◽  
Vol 30 (4) ◽  
pp. 362-364
Author(s):  
Degui Li ◽  
Ming Qin ◽  
Liuqing Liang ◽  
Changsheng Qin ◽  
Chenzhong Jia ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
Ternary Compound ◽  
Powder Diffraction ◽  
Hexagonal Structure ◽  
Argon Atmosphere ◽  
Arc Furnace ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray

The ternary compound of AlCu4Y was synthesized by melting under argon atmosphere in the arc furnace. High-quality X-ray powder diffraction data of AlCu4Y have been collected using a Rigaku SmartLab X-ray powder diffractometer. The Rietveld refinement results of the X-ray diffraction pattern for the AlCu4Y compound showed that the AlCu4Y is the hexagonal structure, space-group P6/mmm (No. 191) with a = 5.0658(1) Å, c = 4.1569(1) Å, V = 92.38 Å3, Z = 1, and the density is 6.66 g cm−3, and the intensity ratio RIR is 1.96.

scholarly journals PHASE ANALYSIS OF NITI WIRE BASED ON SYNCHROTRON 2D X-RAY DIFFRACTION PATTERN IN MATLAB

2017 ◽  
Vol 9 ◽  
pp. 8
Author(s):  
Martin Dudr ◽  
Daniel Šimek ◽  
Jan Drahokoupil
Keyword(s):  
Diffraction Pattern ◽  
Phase Analysis ◽  
Phase Content ◽  
X Ray Diffraction ◽  
Niti Wire ◽  
X Ray ◽  
Combined Load ◽  
Quantitative Phase ◽  
Debye Ring ◽  
Diffraction Patterns

This paper deals with simplified phase analysis of 2D diffraction patterns obtained using microfocused X-ray at various places of superelastic NiTi wire under combined load. For this purpose, MATLAB routines and functions were created, which carry out integration of the patterns in various sectors of Debye ring, fitting of the patterns by a mixture of austenite and martensite (having neglected the R-phase) and successive evaluation of the quantitative phase content. The most crucial simplificating assumptions were: the neglection of the R-phase and the assumption of a) fibre texture or b) no texture.

Crystal structure of copper(ii) citrate monohydrate solved from a mixture powder X-ray diffraction pattern

2013 ◽  
Vol 29 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Ana Palčić ◽  
Ivan Halasz ◽  
Josip Bronić
Keyword(s):  
Crystal Structure ◽  
Diffraction Pattern ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Indexing Structure ◽  
Pattern Approach ◽  
Structure Solution ◽  
Diffraction Patterns

The crystal structure of copper(ii) citrate monohydrate (C6H4O7Cu2·H2O) has been solved from a mixture powder diffraction pattern. Approach to indexing, structure solution and Rietveld refinement of multiphase diffraction patterns is discussed. Rietveld refinement is carried out employing free-atom refinement and rigid body refinement.

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