[en] Results of the study produced the following conclusions: higher line density gratings could be produced immediately by superimposing existing gratings (after reducing wire widths); unwanted higher orders could be reduced by chemical treatment of existing ''deep groove'' gratings; symmetric phase gratings could be produced immediately by plating with a low absorption material instead of with gold; symmetric phase plates (gratings) can be etched with existing equipment (a combination of two would focus beam on a spot, with up to 16% efficiency); to improve performance, eventually one should manufacture asymmetric phase gratings, and ''tailor'' the contours of absorption gratings; in the longrun, probably ''shingle gratings'' will offer the best performance; and the conjectured ''Impossibility Theorem'' may limit the performance of gratings, no mater how they are constructed

No abstract available

[en] Four hundred and fourteen references concerning x-ray diffraction occurring in published literature from mid 1977 through late 1979 are cited in this review. The review places emphasis on new developments in applications and instrumentation in both single crystal and powder diffraction; however, the topic of crystal structure analysis has been ignored except in the area of new instrumentation. Compound analysis has also been omitted where emhasis was on the compound rather than the method. Some topics covered in the review are synchrotron radiation applications, x-ray sources, flash x-ray techniques, detectors, image intensifiers, double-crystal diffractometers, precision diffractometers, single-crystal devices, x-ray topography, computer automation, diffractometry, low-temperature diffractometry, high-temperature diffractometry, special-handling techniques or equipment, quantitative analysis, line profile theory, profile analysis, stress analysis, crystallographic texture, computer programs, powder pattern indexing, computer/search/match techniques, powder cameras, and powder pattern in general

[en] A methodological analysis to determine the end of the preinduction period of cement, via X-ray diffraction of ettringite characterization, was developed. Ordinaries portlands cements (OPC) samples were analysed 'in natura' and after water and acetone additions. The acetone was added at diferent time intervals to interrupt the hydration reactions and in order to perform the analysis. Detailed experimental steps are included. (Author)

[en] A model of the chain breaking with a modification of the ending groups in a crystal area is proposed for an explanation of parameter changes in the γ-irradiated polyethylene crystal cells. The melting enthalpy of polyethylene crystal parts is calculated by the method independent of calorimetry. 8 refs

[en] Short communication

[en] The collimator is applicable to X-ray topographic and X-ray diffractometric investigation of curved monocrystals and of the layers on such monocrystals with the help of two- and multicrystal techniques. It permits the defined curving of a collimator crystal adjustable during measurements

[en] The F. tularensis protein IglE from the FPI, which is a component of the type VI-like secretion system, has been crystallized and preliminary X-ray data have been collected. Tularaemia is an uncommon but potentially dangerous zoonotic disease caused by the bacterium Francisella tularensis. As few as ten bacterial cells are sufficient to cause disease in a healthy human, making this one of the most infectious disease agents known. The virulence of this organism is dependent upon a genetic locus known as the Francisella pathogenicity island (FPI), which encodes components of a secretion system that is related to the type VI secretion system. Here, the cloning, expression, purification and preliminary X-ray diffraction statistics of the FPI-encoded protein IglE are presented. This putative lipoprotein is required for intra-macrophage growth and is thought to be a constituent of the periplasmic portion of the type VI-like protein complex that is responsible for the secretion of critical virulence factors in Francisella

[en] The peptidyl-tRNA hydrolase from M. tuberculosis has been crystallized in three closely related forms, two orthorhombic and one monoclinic, and X-ray diffraction data have been collected from them. Peptidyl-tRNA hydrolase catalyses the cleavage of the ester link between the peptide and the tRNA in peptidyl-tRNAs that, for various reasons, have dropped off the translating ribosomes. This enzyme from Mycobacterium tuberculosis has been crystallized in three related but distinct forms: P2₁2₁2₁, unit-cell parameters a = 36.30, b = 61.85, c = 73.97 Å, P2₁, a = 35.83, b = 73.79, c = 59.79 Å, β = 92.3°, and P2₁2₁2₁, a = 35.84, b = 57.06, c = 72.59 Å. X-ray data have been collected from all three forms

[en] Published in summary form only