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Synchrotron Source (synchrotron + source)
Selected AbstractsFocusing capillary optics for use in solution small-angle X-ray scatteringJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2007Jessica S. Lamb Measurements of the global conformation of macromolecules can be carried out using small-angle X-ray scattering (SAXS). Glass focusing capillaries, manufactured at the Cornell High Energy Synchrotron Source (CHESS), have been successfully employed for SAXS measurements on the heme protein cytochrome c. These capillaries provide high X-ray flux into a spot size of tens of micrometres, permitting short exposures of small-volume samples. Such a capability is ideal for use in conjunction with microfluidic mixers, where time resolution may be determined by beam size and sample volumes are kept small to facilitate mixing and conserve material. [source] Monodisperse Bile-Salt Nanotubes in Water: Kinetics of Formation,ADVANCED MATERIALS, Issue 6 2005B. Jean Sodium lithocholate forms stabilized cylindrical nanotubes with thin monomolecular walls (see Figure) through fast and complex morphological evolutions. The kinetics of formation can be followed by small-angle X-ray scattering using a brilliant synchrotron source, and are corroborated by cryo-transmission electron microscopy. Coaxial cylinders, helical ribbons, fibrils, and single-walled tubes are found to coexist in the first few minutes of the supramolecular organization process. [source] Microradian X-ray diffraction in colloidal photonic crystalsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2006J. H. J. Thijssen Ultra-high-resolution small-angle X-ray scattering in various colloidal photonic crystals is reported. It is demonstrated that an angular resolution of about two microradians is readily achievable at a third-generation synchrotron source using compound refractive optics. The scheme allows fast acquisition of two-dimensional X-ray diffraction data and can be realised at sample,detector separations of only a few metres. As a result, diffraction measurements in colloidal crystals with interplanar spacings larger than a micrometre, as well as determination of the range of various order parameters from the width of the Bragg peaks, are made possible. [source] Spatial resolution limits for synchrotron-based spectromicroscopy in the mid- and near-infraredJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2008Erika Levenson Spatial resolution tests were performed on beamline 1.4.4 at the Advanced Light Source in Berkeley, CA, USA, a third-generation synchrotron light source. This beamline couples the high-brightness synchrotron source to a Thermo-Electron Continuµm XL infrared microscope. Two types of resolution tests were performed in both the mid-IR and near-IR. The results are compared with a diffraction-limited spot size theory. At shorter near-IR wavelengths the experimental results begin to deviate from diffraction-limited so a combined diffraction-limit and electron-beam-source-size model is employed. This description shows how the physical electron beam size of the synchrotron source begins to dominate the focused spot size at higher energies. The transition from diffraction-limited to electron-beam-size-limited performance is a function of storage-ring parameters and the optical demagnification within the beamline and microscope optics. The discussion includes how different facilities, beamlines and microscopes will affect the achievable spatial resolution. As synchrotron light sources and other next-generation accelerators such as energy-recovery LINACs and free-electron lasers achieve smaller beam emittances, beta-functions and/or energy spreads, diffraction-limited performance can continue to higher-energy beams, perhaps ultimately into the extreme ultraviolet. [source] Quantitative studies of pyrocarbon-coated materials using synchrotron radiationJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2008Poonamlata S. Yadav Phase-contrast imaging provides enhanced image contrast and is important for non-destructive evaluation of structural materials. In this paper, experimental results on in-line phase-contrast imaging using a synchrotron source (ELETTRA, Italy) for objects required in material science applications are discussed. Experiments have been carried out on two types of samples, pyrocarbon-coated zirconia and pyrocarbon-coated alumina microspheres. These have applications in both reactor and industrial fields. The phase-contrast imaging technique is found to be very useful in visualizing and determining the coating thickness of pyrocarbon on zirconia and alumina microspheres. The experiments were carried out at X-ray energies of 16, 18 and 20,keV and different object-to-detector distances. The results describe the contrast values and signal-to-noise ratio for both samples. A comprehensive study was carried out to determine the thickness of the pyrocarbon coating on zirconia and alumina microspheres of diameter 500,µm. The advantages of phase-contrast images are discussed in terms of contrast and resolution, and a comparison is made with absorption images. The results show considerable improvement in contrast with phase-contrast imaging as compared with absorption radiography. [source] XAFS experiments at beamline I811, MAX-lab synchrotron source, SwedenJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2006Stefan Carlson A description of a new facility for X-ray absorption spectroscopy at the materials science beamline, I811, at MAX-lab synchrotron source, Lund, Sweden, is given. The beamline is based on a superconducting multipole wiggler source inserted in a straight section of the 1.5,GeV MAX-II ring. X-rays in the energy range 2.4,12,keV are extracted by a standard optical scheme consisting of a vertical collimating first mirror, double-crystal monochromator, and a second vertically focusing mirror. The second monochromator crystal provides sagittal focusing. The total flux impinging on the sample at 9,keV is 5 × 1011,photons,s,1, for a minimum beam spot of 0.5,mm × 0.5,mm. The beamline has facilities for experiments in transmission, fluorescence and total-electron-yield mode and experiments have been performed by international research groups on a wide range of materials, such as dilute systems with metal concentrations below 10,p.p.m. [source] Studies of the magnetic structure at the ferromagnet,antiferromagnet interfaceJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001A. Scholl Antiferromagnetic layers are a scientifically challenging component in magnetoelectronic devices, such as magnetic sensors in hard-disk heads, or magnetic random-access memory (RAM) elements. In this paper, it is shown that photoelectron emission microscopy (PEEM) is capable of determining the magnetic structure at the interface of ferromagnets and antiferromagnets with high spatial resolution (down to 20,nm). Dichroism effects at the L edges of the magnetic 3d transition metals, using circularly or linearly polarized soft X-rays from a synchrotron source, give rise to a magnetic image contrast. Images, acquired with the PEEM2 experiment at the Advanced Light Source, show magnetic contrast for antiferromagnetic LaFeO3, microscopically resolving the magnetic domain structure in an antiferromagnetically ordered thin film for the first time. Magnetic coupling between LaFeO3 and an adjacent Co layer results in a complete correlation of their magnetic domain structures. From field-dependent measurements, a unidirectional anisotropy resulting in a local exchange bias of up to 30,Oe in single domains could be deduced. The elemental specificity and the quantitative magnetic sensitivity render PEEM a perfect tool to study magnetic coupling effects in multilayered thin-film samples. [source] Crystallization and preliminary X-ray crystallographic analysis of the laminarinase endo-,-1,3-glucanase from Pyrococcus furiosusACTA CRYSTALLOGRAPHICA SECTION D, Issue 12-2 2004Andrea Ilari Laminarinase endo-,-1,3 glucanase (LamA) from Pyrococcus furiosus is an enzyme which displays its main hydrolytic activity on the ,-1,3-glucose polymer laminarin. This laminarinase is remarkably resistant to denaturation: its secondary structure is unchanged in 8,M guanidinium chloride. This protein belongs to the family 16 glycosyl hydrolases, which are enzymes that are widely distributed among bacteria, fungi and higher plants. Single crystals of P. furiosus LamA have been obtained by the hanging-drop vapour-diffusion method using 2-methyl-2,4-pentanediol as a precipitant agent. A complete data set has been collected under cryocooling at a synchrotron source. The crystals belong to the monoclinic space group P21, with unit-cell parameters a = 44.36, b = 84.76, c = 69.23,Å, , = 90, , = 104.97, , = 90°, and diffract to 2.15,Å resolution. [source] Purification, crystallization and preliminary X-ray diffraction of a proteolytic fragment of PDK1 containing the pleckstrin homology domainACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2004David Komander 3-Phosphoinositide-dependent protein kinase-1 (PDK1) is a Ser/Thr kinase with an essential role in insulin and growth-factor signalling. PDK1 activity towards protein kinase B (PKB) is partially regulated by its pleckstrin homology (PH) domain, which preferentially binds to 3-phosphoinositides. However, the precise molecular mechanism of this regulation is not well understood. Here, the cloning, purification and crystallization of a 150-amino-acid C-terminal region of PDK1 containing the PH domain is reported. A crystal of the PDK1 PH domain grown in the presence of inositol 1,3,4,5-tetrakisphosphate and derivatized with AuCN diffracted to 1.5,Å at a synchrotron source. Diffraction data collected near the Au edge resulted in an anomalous Patterson map with a 30, peak. [source] Crystallization and preliminary X-ray analysis of Der f 2, a potent allergen derived from the house dust mite (Dermatophagoides farinae)ACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2003Dana Roeber Although a number of allergens have been identified and isolated, the underlying molecular basis for the potent immune response is poorly understood. House dust mites (Dermatophagoides sp.) are ubiquitous contributors to atopy in developed countries. The rhinitis, dermatitis and asthma associated with allergic reactions to these arthropods are frequently caused by relatively small (125,129 amino acids) mite proteins of unknown biological function. Der,f,2, a major allergen from the mite D.,farinae, has been recombinantly expressed, characterized and crystallized. The crystals belong to the tetragonal space group I4122, with unit-cell parameters a = b = 95.2, c = 103.3,Å. An essentially complete (97.2%) data set has been collected to 2.4,Å at a synchrotron source. Attempts to solve the crystal structure of Der,f,2 by molecular replacement using the NMR coordinates for either Der,f,2 or Der,p,2 (the homologous protein from D.,pteronyssinus) failed, but preliminary searches using the crystalline Der p 2 atomic coordinates appear to be promising. [source] Purification, crystallization and preliminary X-ray analysis of a ,-like calpainACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2003Gour P. Pal The X-ray structure of m-calpain in the absence of Ca2+ has been described, but it has not been possible to obtain sufficient ,-calpain for structure determination. Comparison of the two structures is of interest in attempting to understand their different Ca2+ requirements. Here, the crystallization in the absence of Ca2+ of an inactive mutant hybrid calpain (MW , 100,kDa), which contains 85% of the rat ,-calpain sequence and is well expressed in Escherichia coli, is described. The properties of this calpain in its active form and particularly its Ca2+ requirement are close to those expected for wild-type ,-calpain. Clusters of plate-shaped crystals were obtained by vapour diffusion with polyethylene glycol (Mr, 6000) as precipitating agent in the presence of detergent. The crystals diffract to a resolution of 2.7,Å at a synchrotron source. The space group is P21, with unit-cell parameters a = 72.7, b = 184.6, c = 86.3,Å, , = 100.7°. There are two molecules in the asymmetric unit, corresponding to a solvent content of 57.1%. [source] Crystallization and preliminary X-ray study of haem-binding protein from the bloodsucking insect Rhodnius prolixusACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2001R. A. P. Nagem Rhodnius haem-binding protein (RHBP) from the bloodsucking insect Rhodnius prolixus, a 15,kDa protein, has been crystallized using polyethylene glycol as a precipitant. X-ray diffraction data have been collected at a synchrotron source. The crystals belong to the space group P41(3)212, with unit-cell parameters a = b = 64.98, c = 210.68,Å, and diffract beyond 2.6,Å resolution. [source] Caged and clustered structures of endothelin inhibitor BQ123, cyclo(- d -Trp- d -Asp, -Pro- d -Val-Leu-),Na+, forming five and six coordination bonds between sodium ions and peptidesACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2001Mitsunobu Doi BQ123 is a cyclic pentapeptide and a potent endothelin-1 inhibitor. The crystal structure of the BQ123 sodium salt was determined as the first example of an endothelin inhibitor. Four independent molecules and many solvent molecules were found in the asymmetric unit; the total weight was about 3000,Da. The precise structure including the solvent molecules was determined using high-resolution data collected on a synchrotron source. Sodium ions formed unique structures with five and six coordination bonds and their forms were distinguished into three classes. An ion was sandwiched by two BQ123 molecules. This peptide,sodium (2:1) complex showed a cage-like structure and octahedral coordination was observed. Sodium ions also formed a cluster composed of hydrated water molecules and peptides. Two sodium ions were contained in this cluster, making five coordination bonds. Despite having the same coordination numbers, these ions were distinguishable by differences in the polyhedra. One was trigonal bipyramidal (having six planes) and the other was square pyramidal (having five planes). Both shapes were very similar to each other, although the synchrotron data clearly revealed slight geometrical differences. [source] Purification, crystallization and preliminary diffraction study of ,-galactosidase from Penicillium sp.ACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2000K. N. Neustroev Crystals of an extracellular ,-galactosidase from Penicillium sp. (MW = 120 ± 5,kDa) have been obtained from a sodium phosphate buffer using PEG as precipitant. The crystals belong to the tetragonal space group P41or P43, with unit-cell parameters a = b = 110.82, c = 161.28,Å, and diffract to 1.85,Å resolution at a synchrotron source. [source] Crystallization and preliminary X-ray diffraction data of ,-galactosidase from Saccharomyces cerevisiaeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2010Rafael Fernández-Leiro Saccharomyces cerevisiae,-galactosidase is a highly glycosylated extracellular protein that catalyzes the hydrolysis of ,-galactosidic linkages in various glucids. Its enzymatic activity is of interest in many food-related industries and has biotechnological applications. Glycosylated and in vitro deglycosylated protein samples were both assayed for crystallization, but only the latter gave good-quality crystals that were suitable for X-ray crystallography. The crystals belonged to space group P4212, with unit-cell parameters a = b = 101.24, c = 111.52,Å. A complete diffraction data set was collected to 1.95,Å resolution using a synchrotron source. [source] Crystallization and preliminary X-ray diffraction analysis of inositol 1,3,4,5,6-pentakisphosphate kinase from Arabidopsis thalianaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2010Jose Ignacio Baños-Sanz Inositol 1,3,4,5,6-pentakisphosphate kinase (IP5 2-K) is an enzyme involved in inositol metabolism that synthesizes IP6 (inositol 1,2,3,4,5,6-hexakisphosphate) from inositol 1,3,4,5,6-pentakisphosphate (IP5) and ATP. IP6 is the major phosphorus reserve in plants, while in mammals it is involved in multiple cellular events such as DNA editing and chromatin remodelling. In addition, IP6 is the precursor of other highly phosphorylated inositols which also play highly relevant roles. IP5 2-K is the only enzyme that phosphorylates the 2-OH axial position of the inositide and understanding its molecular mechanism of substrate specificity is of great interest in cell biology. IP5 2-K from Arabidopsis thaliana has been expressed in Escherichia coli as two different fusion proteins and purified. Both protein preparations yielded crystals of different quality, always in the presence of IP6. The best crystals obtained for X-ray crystallographic analysis belonged to space group P212121, with unit-cell parameters a = 58.124, b = 113.591, c = 142.478,Å. Several diffraction data sets were collected for the native enzyme and two heavy-atom derivatives using a synchrotron source. [source] Crystallization and preliminary X-ray diffraction analysis of the fructofuranosidase from Schwanniomyces occidentalisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2009Aitana Polo Schwanniomyces occidentalis invertase is an extracellular enzyme that releases ,-fructose from the nonreducing termini of various ,- d -fructofuranoside substrates. Its ability to produce 6-kestose by transglycosylation makes this enzyme an interesting research target for applications in industrial biotechnology. The enzyme has been expressed in Saccharomyces cerevisiae. Recombinant and wild-type forms, which showed different glycosylation patterns, were crystallized by vapour-diffusion methods. Although crystallization trials were conducted on both forms of the protein, crystals suitable for X-ray crystallographic analyses were only obtained from the wild-type enzyme. The crystals belonged to space group P212121, with unit-cell parameters a = 105.78, b = 119.49, c = 137.68,Å. A diffraction data set was collected using a synchrotron source. Self-rotation function and sedimentation-velocity experiments suggested that the enzyme was dimeric with twofold symmetry. [source] Crystallization and preliminary diffraction analysis of a ,-galactosidase from Trichoderma reeseiACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 8 2009Mirko Maksimainen An extracellular ,-galactosidase from Trichoderma reesei was crystallized from sodium cacodylate buffer using polyethylene glycol (PEG) as a precipant. Crystals grown by homogenous streak-seeding belonged to space group P1, with unit-cell parameters a = 67.3, b = 69.1, c = 81.5,Å, , = 109.1, , = 97.3, , = 114.5°. The crystals diffracted to 1.8,Å resolution using a rotating-anode generator and to 1.2,Å resolution using a synchrotron source. On the basis of the Matthews coefficient (VM = 3.16,Å3,Da,1), one molecule is estimated to be present in the asymmetric unit. The aim of the determination of the crystal structure is to increase the understanding of this industrially significant enzyme. [source] Expression, crystallization and preliminary crystallographic analysis of PilZXAC1133 from Xanthomonas axonopodis pv. citriACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2009Cristiane R. Guzzo Proteins containing PilZ domains are widespread in Gram-negative bacteria and have recently been shown to be involved in the control of biofilm formation, adherence, aggregation, virulence-factor production and motility. Furthermore, some PilZ domains have recently been shown to bind the second messenger bis(3,,5,)cyclic diGMP. Here, the cloning, expression, purification and crystallization of PilZXAC1133, a protein consisting of a single PilZ domain from Xanthomonas axonopodis pv. citri, is reported. The closest PilZXAC1133 homologues in Pseudomonas aeruginosa and Neisseria meningitidis control type IV pilus function. Recombinant PilZXAC1133 containing selenomethionine was crystallized in space group P61. The unit-cell parameters were a = 62.125, b = 62.125, c = 83.543,Å. These crystals diffracted to 1.85,Å resolution and a MAD data set was collected at a synchrotron source. The calculated Matthews coefficient suggested the presence of two PilZXAC1133 molecules in the asymmetric unit. [source] Crystallization and preliminary X-ray analysis of LipL32 from Leptospira interrogans serovar CopenhageniACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2009Pricila Hauk LipL32 is a major surface protein that is expressed during infection by pathogenic Leptospira. Here, the crystallization of recombinant LipL3221,272, which corresponds to the mature LipL32 protein minus its N-terminal lipid-anchored cysteine residue, is described. Selenomethionine-labelled LipL3221,272 crystals diffracted to 2.25,Å resolution at a synchrotron source. The space group was P3121 or P3221 and the unit-cell parameters were a = b = 126.7, c = 96.0,Å. [source] Expression, purification, crystallization and preliminary X-ray analysis of an archaeal protein homologous to plant nicotianamine synthaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2008Cyril Dreyfus In plants, nicotianamine synthase (NAS) plays a key role in metal homeostasis as it catalyzes the formation of nicotianamine, an important iron and nickel chelator and a precursor of plant phytosiderophores. Here, the crystallization of a protein from Methanothermobacter thermoautotrophicus (MTH675; referred to here as MtNAS) that appears to be homologous to plant NAS is reported. Purification of this protein showed a monomer,dimer equilibrium that could be displaced by using a reducing agent such as DTT. Crystals belonging to space group P212121 and containing dimers of MtNAS were grown by the vapour-diffusion method using polyethylene glycol 3350 as precipitant. A complete native X-ray data set was collected to 1.7,Å resolution at a synchrotron source. [source] Purification, crystallization and preliminary X-ray crystallographic analysis of the nucleocapsid protein of Bunyamwera virusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2006Qingxian Zhou Bunyamwera virus (BUNV) is the prototypic member of the Bunyaviridae family of segmented negative-sense RNA viruses. The BUNV nucleocapsid protein has been cloned and expressed in Escherichia coli. The purified protein has been crystallized and a complete data set has been collected to 3.3,Å resolution at a synchrotron source. Crystals of the nucleocapsid protein belong to space group C2, with unit-cell parameters a = 384.7, b = 89.8, c = 89.2,Å, , = 94.4°. Self-rotation function analysis of the X-ray diffraction data has provided insight into the oligomeric state of the protein as well as the orientation of the oligomers in the asymmetric unit. The structure determination of the protein is ongoing. [source] Expression, crystallization and preliminary crystallographic analysis of SufE (XAC2355) from Xanthomonas axonopodis pv. citriACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2006Cristiane R. Guzzo Xanthomonas axonopodis pv. citri (Xac) SufE (XAC2355) is a member of a family of bacterial proteins that are conserved in several pathogens and phytopathogens. The Escherichia coli suf operon is involved in iron,sulfur cluster biosynthesis under iron-limitation and stress conditions. It has recently been demonstrated that SufE and SufS form a novel two-component cysteine desulfarase in which SufS catalyses the conversion of l -cysteine to l -alanine, forming a protein-bound persulfide intermediate. The S atom is then transferred to SufE, from which it is subsequently transferred to target molecules or reduced to sulfide in solution. Here, the cloning, expression, crystallization and phase determination of Xac SufE crystals are described. Recombinant SufE was crystallized in space group P212121 and diffracted to 1.9,Å resolution at a synchrotron source. The unit-cell parameters are a = 45.837, b = 58.507, c = 98.951,Å, , = , = , = 90°. The calculated Matthews coefficient indicated the presence of two molecules in the asymmetric unit. Phasing was performed by molecular-replacement using E. coli SufE as a model (PDB code 1mzg) and an interpretable map was obtained. [source] Preliminary crystallographic studies of glucose dehydrogenase from the promiscuous Entner,Doudoroff pathway in the hyperthermophilic archaeon Sulfolobus solfataricusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2005Alex Theodossis The hyperthermophilic archaeon Sulfolobus solfataricus grows optimally above 353,K and can metabolize glucose and its C4 epimer galactose via a non-phosphorylative variant of the Entner,Doudoroff pathway involving catalytically promiscuous enzymes that can operate with both sugars. The initial oxidation step is catalysed by glucose dehydrogenase (SsGDH), which can utilize both NAD and NADP as cofactors. The enzyme operates with glucose and galactose at similar catalytic efficiency, while its substrate profile also includes a range of other five- and six-carbon sugars. Crystals of the 164,kDa SsGDH homotetramer have been grown under a variety of conditions. The best crystals to date diffract to 1.8,Å on a synchrotron source, have orthorhombic symmetry and belong to space group P21212. Attempts are being made to solve the structure by MAD and MR. [source] Impact of synchrotron radiation on macromolecular crystallography: a personal viewJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2010Zbigniew Dauter The introduction of synchrotron radiation sources almost four decades ago has led to a revolutionary change in the way that diffraction data from macromolecular crystals are being collected. Here a brief history of the development of methodologies that took advantage of the availability of synchrotron sources are presented, and some personal experiences with the utilization of synchrotrons in the early days are recalled. [source] Coherence and wavefront characterization of Si-111 monochromators using double-grating interferometryJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2010Ana Diaz A study of the coherence and wavefront properties of a pseudo-channel-cut monochromator in comparison with a double-crystal monochromator is presented. Using a double-grating interferometer designed for the hard X-ray regime, the complex coherence factor was measured and the wavefront distortions at the sample position were analyzed. A transverse coherence length was found in the vertical direction that was a factor of two larger for the channel-cut monochromator owing to its higher mechanical stability. The wavefront distortions after different optical elements in the beam, such as monochromators and mirrors, were also quantified. This work is particularly relevant for coherent diffraction imaging experiments with synchrotron sources. [source] Advances and synergy of high-pressure sciences at synchrotron sourcesJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2009Haozhe Liu Introductory overview to the special issue papers on high-pressure sciences and synchrotron radiation. [source] Characterization of germanium linear kinoform lenses at Diamond Light SourceJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2009L. Alianelli The unprecedented brilliance achieved by third-generation synchrotron sources and the availability of improved optics have opened up new opportunities for the study of materials at the micrometre and nanometre scale. Focusing the synchrotron radiation to smaller and smaller beams is having a huge impact on a wide research area at synchrotrons. The key to the exploitation of the improved sources is the development of novel optics that deliver narrow beams without loss of brilliance and coherence. Several types of synchrotron focusing optics are successfully fabricated using advanced miniaturization techniques. Kinoform refractive lenses are being developed for hard X-ray beamlines, and the first test results at Diamond are discussed in this paper. [source] Study of micro-channel geometries for internally cooled Si monochromatorsJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2008P. Oberta Rocking curves of micro-channel (MC) water-cooled monochromators are broadened by stresses introduced during fabrication and under X-ray thermal load. This is a problem which will be even more serious with the rise of the fourth-generation synchrotron sources, i.e. the free-electron lasers. The X-ray optics group at the Institute of Physics at the ASCR v.v.i. in Prague is designing, testing and, with company Polovodi,e a.s., fabricating novel internally water-cooled Si monochromators. Here three new micro-channel geometries are introduced which reduce rocking-curve enlargement owing to the fabrication to less than 2.5,µrad (,0.5,arcsec). All three MC designs show less rocking-curve enlargement and smoother topographic images. The designs also show better cooling efficiencies than the classical MC design in finite-element analysis calculations. [source] High-resolution wide-angle X-ray scattering of protein solutions: effect of beam dose on protein integrityJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2003Robert F. Fischetti Wide-angle X-ray scattering patterns from proteins in solution contain information relevant to the determination of protein fold. At relevant scattering angles, however, these data are weak, and the degree to which they might be used to categorize the fold of a protein is unknown. Preliminary work has been performed at the BioCAT insertion-device beamline at the Advanced Photon Source which demonstrates that one can collect X-ray scattering data from proteins in solution to spacings of at least 2.2,Å (q = 2.8,Å,1). These data are sensitive to protein conformational states, and are in good agreement with the scattering predicted by the program CRYSOL using the known three-dimensional atomic coordinates of the protein. An important issue in the exploitation of this technique as a tool for structural genomics is the extent to which the high intensity of X-rays available at third-generation synchrotron sources chemically or structurally damage proteins. Various data-collection protocols have been investigated demonstrating conditions under which structural degradation of even sensitive proteins can be minimized, making this technique a viable tool for protein fold categorization, the study of protein folding, unfolding, protein,ligand interactions and domain movement. [source] | |||||||||||||