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Diffraction Properties (diffraction + property)
Selected AbstractsSelf-assembled honeycomb polycarbonate films deposited on polymer piezoelectric substrates and their applicationsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 4 2005Edward Bormashenko Abstract Self-assembled honeycomb polycarbonate films were deposited on polymer piezoelectric (poled polyvinylidene fluoride) substrates under a fast dip-coating process. Ordered structures with micro-scaled pores dispersed in the polycarbonate matrix were obtained, demonstrating two-dimensional (2D) hexagonal packing. A theoretical model explaining the self-assembling process is proposed. Fabricated structures have a potential as 2D tunable photonic crystals. Photonic bandgap location was estimated. Visible-IR transmittance spectrum of the self-assembled films was studied with a FT-IR spectrometer. Diffraction properties of the honeycomb patterns were investigated. High transparency of the components makes possible IR optics applications of obtained structures. Copyright © 2005 John Wiley & Sons, Ltd. [source] Synthesis and preliminary characterization of sulfamethazine-theophylline co-crystalJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2010Jie Lu Abstract Co-crystals containing active pharmaceutical ingredients (APIs) represent a new type of pharmaceutical materials. In this work, sulfamethazine (STH) and theophylline (TP) were employed as the co-crystal formers. Neat cogrinding, solvent-drop cogrinding and slow evaporation were applied to synthesize the sulfamethazine,theophylline co-crystal (hereafter STH,TP co-crystal). The co-crystalline phase was characterized by DSC, TGA, Raman, PXRD, and dynamic vapor sorption (DVS) techniques. The STH,TP co-crystal structure was determined from single crystal X-ray diffraction data. The results show that, the STH,TP co-crystal, obtained in a 2:1 molar ratio of sulfamethazine and theophylline only by slow evaporation, possesses unique thermal, spectroscopic, and X-ray diffraction properties. Besides, in the STH,TP co-crystal, the sulfamethazine molecules form a dimer through the intermolecular hydrogen bonding (O ··· H N), and two intermolecular hydrogen bonds (O ··· H N and N ··· H N) keep the theophylline attached the dimer. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4042,4047, 2010 [source] Analysis of SR thermal load studied by FEAPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2007Abstract This work deals with analysis of the thermal effects and inherent mechanical deformations under absorption of the X-ray beam heat. The work is motivated by recent research concentrated on the development of optics for high-flux synchrotron radiation sources. We present the analyses of the static thermal load effects on the surface deformation field for a monocrystalline silicon target, which is the basic material for crystal X-ray optics. The surface and bulk thermal load induces the gradient of temperature and mechanical deformations of the target that are affecting the reflection and diffraction properties of the target. The paper presents the finite-element analyses (FEA) and simulation results of mechanical deformation of flat and slotted silicon targets. The hints for improved target geometry and physical limits for an actual cooling system can be obtained from the presented analyses. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Improving diffraction by humidity control: a novel device compatible with X-ray beamlinesACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2009Juan Sanchez-Weatherby Dehydration of protein crystals is rarely used, despite being a post-crystallization method that is useful for the improvement of crystal diffraction properties, as it is difficult to reproduce and monitor. A novel device for hydration control of macromolecular crystals in a standard data-collection environment has been developed. The device delivers an air stream of precise relative humidity that can be used to alter the amount of water in macromolecular crystals. The device can be rapidly installed and is fully compatible with most standard synchrotron X-ray beamlines. Samples are mounted in cryoloops and the progress of dehydration can be monitored both optically and by the acquisition of diffraction images. Once the optimal hydration level has been obtained, cryocooling is easy to achieve by hand or by using a sample changer. The device has been thoroughly tested on several ESRF beamlines and is available to users. [source] The Biomolecular Crystallization Database Version 4: expanded content and new featuresACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2009Michael Tung The Biological Macromolecular Crystallization Database (BMCD) has been a publicly available resource since 1988, providing a curated archive of information on crystal growth for proteins and other biological macromolecules. The BMCD content has recently been expanded to include 14,372 crystal entries. The resource continues to be freely available at http://xpdb.nist.gov:8060/BMCD4. In addition, the software has been adapted to support the Java-based Lucene query language, enabling detailed searching over specific parameters, and explicit search of parameter ranges is offered for five numeric variables. Extensive tools have been developed for import and handling of data from the RCSB Protein Data Bank. The updated BMCD is called version 4.02 or BMCD4. BMCD4 entries have been expanded to include macromolecule sequence, enabling more elaborate analysis of relations among protein properties, crystal-growth conditions and the geometric and diffraction properties of the crystals. The BMCD version 4.02 contains greatly expanded content and enhanced search capabilities to facilitate scientific analysis and design of crystal-growth strategies. [source] Cloning, expression, crystallization and preliminary X-ray crystallographic analysis of a human condensin SMC2 hinge domain with short coiled coilsACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Kazuki Kawahara In higher eukaryotes, the condensin complex, which mainly consists of two structural maintenance of chromosomes (SMC) subunits, SMC2 (CAP-E) and SMC4 (CAP-C), plays a critical role in the formation of higher order chromosome structures during mitosis. Biochemical and electron-microscopic studies have revealed that the SMC2 and SMC4 subunits dimerize through the interaction of their hinge domains, forming a characteristic V-shaped heterodimer. However, the details of their function are still not fully understood owing to a lack of structural information at the atomic level. In this study, the human SMC2 hinge domain with short coiled coils was cloned, expressed, purified and crystallized in the orthorhombic space group C222 in native and SeMet-derivatized forms. Because of the poor diffraction properties of these crystals, the mutant Leu68,SeMet was designed and crystallized in order to obtain the experimental phases. The SeMet-derivatized crystals of the mutant belonged to space group P3212, with unit-cell parameters a = b = 128.8, c = 91.4,Å. The diffraction data obtained from a crystal that diffracted to 2.4,Å resolution were suitable for SAD phasing. [source] Cloning, expression, purification and crystallization as well as X-ray fluorescence and preliminary X-ray diffraction analyses of human ADP-ribosylhydrolase 1ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2009Stefan Kernstock Human ADP-ribosylhydrolase 1 (hARH1, ADPRH) cleaves the glycosidic bond of ADP-ribose attached to an Arg residue of a protein. hARH1 has been cloned, expressed heterologously in Escherichia coli, purified and crystallized in complex with K+ and ADP. The orthorhombic crystals contained one monomer per asymmetric unit, exhibited a solvent content of 43% and diffracted X-rays to a resolution of 1.9,Å. A prerequisite for obtaining well diffracting crystals was the performance of X-ray fluorescence analysis on poorly diffracting apo hARH1 crystals, which revealed the presence of trace amounts of K+ in the crystal. Adding K-ADP to the crystallization cocktail then resulted in a crystal of different morphology and with dramatically improved diffraction properties. [source] The expression, purification, crystallization and preliminary X-ray analysis of a subcomplex of the peripheral stalk of ATP synthase from bovine mitochondriaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2006Jocelyn A. Silvester A subcomplex of the peripheral stalk or stator domain of the ATP synthase from bovine mitochondria has been expressed to high levels in a soluble form in Escherichia coli. The subcomplex consists of residues 79,184 of subunit b, residues 1,124 of subunit d and the entire F6 subunit (76 residues). It has been purified and crystallized by vapour diffusion. The morphology and diffraction properties of the crystals of the subcomplex were improved by the presence of thioxane or 4-methylpyridine in the crystallization liquor. With a synchrotron-radiation source, these crystals diffracted to 2.8,Å resolution. They belong to the monoclinic space group P21. [source] | ||||||||||