J. Appl. Cryst.の発刊に際して
10 Mar 1970-Vol. 12, Iss: 1, pp 1-1
About: The article was published on 1970-03-10 and is currently open access. It has received 8159 citations till now.
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TL;DR: An automated system for mounting and dismounting pre-frozen crystals has been implemented at the Stanford Synchrotron Radiation Laboratory, based on a small industrial robot and compact cylindrical cassettes.
Abstract: An automated system for mounting and dismounting pre-frozen crystals has been implemented at the Stanford Synchrotron Radiation Laboratory (SSRL). It is based on a small industrial robot and compact cylindrical cassettes, each holding up to 96 crystals mounted on Hampton Research sample pins. For easy shipping and storage, the cassette fits inside several popular dry-shippers and long-term storage Dewars. A dispensing Dewar holds up to three cassettes in liquid nitrogen adjacent to the beamline goniometer. The robot uses a permanent magnet tool to extract samples from, and insert samples into a cassette, and a cryo-tong tool to transfer them to and from the beamline goniometer. The system is simple, with few moving parts, reliable in operation and convenient to use.
267 citations
Cites background from "J. Appl. Cryst.の発刊に際して"
...In order to meet this need, facilities have been constructing new crystallography beamlines, including several at third-generation synchrotron sources, and obtaining CCD-based area detectors with readout times approaching one second (Phillips et al., 2000)....
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...The system is simple, with few moving parts, reliable in operation and convenient to use....
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15 Jan 1999-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, applied and residual lattice strains were determined by neutron diffraction during a tensile test of a weakly textured austenitic stainless steel and were compared to the predictions of a self-consistent polycrystal deformation model.
Abstract: Applied and residual lattice strains were determined by neutron diffraction during a tensile test of a weakly textured austenitic stainless steel and were compared to the predictions of a self-consistent polycrystal deformation model. Parallel to the tensile axis the model predictions are generally within the resolution of the diffraction measurements, but perpendicular to the tensile axis discrepancies are noted. Discrepancies between model and measurements were greater for the residual lattice strains than during loading. It is postulated that this is because the model does not predict reverse plasticity during unload.
265 citations
Cites background from "J. Appl. Cryst.の発刊に際して"
...This small grain size ensures that the diffraction experiments allow powder diffraction assumptions, since there is a sufficiently large number of grains in the gauge volume to give acceptable volume averages of the specific lattice strains....
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TL;DR: The advent of hard X-ray free-electron lasers has opened a new chapter in macromolecular crystallography and the prospects of serial femtosecond crystallography are described.
263 citations
Cites background or methods from "J. Appl. Cryst.の発刊に際して"
...Ideally, some kind of self-sorting of the crystals (Zarrine-Afsar et al., 2011) is used for mounting in the chip or deposition by acoustic droplet ejection (Soares et al., 2011)....
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...This data-mining step can be performed offline using the programs Cheetah (Barty et al., 2014) or CASS (Foucar et al., 2012) and the resulting hits can be fed into subsequent analysis programs....
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...CrystFEL, the first one available, relies on other programs [e.g. Cheetah (Barty et al., 2014) or CASS (Foucar et al., 2012)] for hit identification....
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TL;DR: In this paper, a semi-automated method has been used to measure all five macroscopically observable parameters of 4.1×10 6 boundary plane segments making up 5.4 mm 2 of boundary area in a hot-pressed magnesia polycrystal.
262 citations
Cites background from "J. Appl. Cryst.の発刊に際して"
...Keywords: Grain boundaries; Ceramics; Microstructure; Electron backscattering patterns (EBSP); Texture...
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TL;DR: The wiggler X-ray source of the Materials Science beamline at the Swiss Light Source has been replaced with a 14 mm-period cryogenically cooled in-vacuum undulator to best exploit the increased brilliance of this new source.
Abstract: The Materials Science beamline at the Swiss Light Source has been operational since 2001 In late 2010, the original wiggler source was replaced with a novel insertion device, which allows unprecedented access to high photon energies from an undulator installed in a medium-energy storage ring In order to best exploit the increased brilliance of this new source, the entire front-end and optics had to be redesigned In this work, the upgrade of the beamline is described in detail The tone is didactic, from which it is hoped the reader can adapt the concepts and ideas to his or her needs
259 citations
References
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TL;DR: The goals of the PDB are described, the systems in place for data deposition and access, how to obtain further information and plans for the future development of the resource are described.
Abstract: The Protein Data Bank (PDB; http://www.rcsb.org/pdb/ ) is the single worldwide archive of structural data of biological macromolecules. This paper describes the goals of the PDB, the systems in place for data deposition and access, how to obtain further information, and near-term plans for the future development of the resource.
34,239 citations
TL;DR: New features added to the refinement program SHELXL since 2008 are described and explained.
Abstract: The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as `a CIF') containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.
28,425 citations
TL;DR: CCP4mg is a project that aims to provide a general-purpose tool for structural biologists, providing tools for X-ray structure solution, structure comparison and analysis, and publication-quality graphics.
Abstract: CCP4mg is a project that aims to provide a general-purpose tool for structural biologists, providing tools for X-ray structure solution, structure comparison and analysis, and publication-quality graphics. The map-fitting tools are available as a stand-alone package, distributed as `Coot'.
27,505 citations
TL;DR: The PHENIX software for macromolecular structure determination is described and its uses and benefits are described.
Abstract: Macromolecular X-ray crystallography is routinely applied to understand biological processes at a molecular level. However, significant time and effort are still required to solve and complete many of these structures because of the need for manual interpretation of complex numerical data using many software packages and the repeated use of interactive three-dimensional graphics. PHENIX has been developed to provide a comprehensive system for macromolecular crystallographic structure solution with an emphasis on the automation of all procedures. This has relied on the development of algorithms that minimize or eliminate subjective input, the development of algorithms that automate procedures that are traditionally performed by hand and, finally, the development of a framework that allows a tight integration between the algorithms.
18,531 citations
TL;DR: A description is given of Phaser-2.1: software for phasing macromolecular crystal structures by molecular replacement and single-wavelength anomalous dispersion phasing.
Abstract: Phaser is a program for phasing macromolecular crystal structures by both molecular replacement and experimental phasing methods. The novel phasing algorithms implemented in Phaser have been developed using maximum likelihood and multivariate statistics. For molecular replacement, the new algorithms have proved to be significantly better than traditional methods in discriminating correct solutions from noise, and for single-wavelength anomalous dispersion experimental phasing, the new algorithms, which account for correlations between F+ and F−, give better phases (lower mean phase error with respect to the phases given by the refined structure) than those that use mean F and anomalous differences ΔF. One of the design concepts of Phaser was that it be capable of a high degree of automation. To this end, Phaser (written in C++) can be called directly from Python, although it can also be called using traditional CCP4 keyword-style input. Phaser is a platform for future development of improved phasing methods and their release, including source code, to the crystallographic community.
17,755 citations