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Hexagonal Crystals (hexagonal + crystal)
Terms modified by Hexagonal Crystals Selected AbstractsIn,Situ Microstructure Control of Oriented Layered Double Hydroxide Monolayer Films with Curved Hexagonal Crystals as Superhydrophobic Materials,ADVANCED MATERIALS, Issue 23 2006H. Chen Oriented NiAl-layered double hydroxide (LDH) films with micro-/nanometer scale binary structures are prepared by in,situ crystallization, without using any external aluminum source or shape-directing surfactant, on a porous anodic alumina/aluminum substrate. The NiAl-LDH film structures can be controlled by tuning crystallization temperature and time. Facile hydrophobic modification of the film surface leads to superhydrophobicity, as shown in the figure. [source] Crystallization and preliminary X-ray analysis of the human vascular adhesion protein-1ACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2003Yvonne Nymalm Human vascular adhesion protein-1 (VAP-1) is a membrane-bound multifunctional glycoprotein with both adhesive and enzymatic properties. The protein belongs to the copper-containing amine oxidase (CAO) family, which use 2,4,5-trihydroxyphenylalanine quinone as a cofactor. Here, the crystallization and preliminary X-ray analysis of a mammalian CAO, human VAP-1, is reported. The protein was expressed in Chinese hamster ovary cells as a full-length form with an N-terminal transmembrane region and multiple glycosylation sites. Hexagonal crystals with unit-cell parameters a = b = 225.9, c = 218.7,Å, , = , = 90, , = 120° were obtained using the vapour-diffusion method. Data from three different crystals were collected at 100,K using synchrotron radiation and were processed to 3.2,Å resolution with 95.9% completeness and an Rmerge of 19.6%. [source] Crystallization and preliminary structure determination of an intact human immunoglobulin, b12: an antibody that broadly neutralizes primary isolates of HIV-1ACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2001Erica Ollmann Saphire An intact human immunoglobulin with a full-length hinge has been crystallized for the first time in a form in which all of the Ig domains are ordered. The IgG1 antibody b12 is one of only three known monoclonal antibodies described that potently neutralize a broad range of HIV-1 primary isolates. It binds to an epitope overlapping the conserved CD4 binding site on the viral surface antigen gp120. Hexagonal crystals corresponding to space group R32 were grown from 0.8,M ammonium sulfate, with unit-cell parameters a = b = 271.3, c = 175.2,Å and one molecule per asymmetric unit. The crystals diffract to 2.8,Å and a preliminary molecular-replacement solution indicates that all 12 Ig domains of the antibody can be resolved. [source] Expression, purification and preliminary X-ray diffraction analysis of the catalytic module of a ,-agarase from the flavobacterium Zobellia galactanivoransACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2010Jan-Hendrik Hehemann Marine bacteria secrete specific glycoside hydrolases such as agarases to access polysaccharides from algal cell walls as a carbon and energy source. In an attempt to identify agarases with variable degradation patterns, a novel family GH16 ,-agarase from the marine bacterium Zobellia galactanivorans was expressed, purified and crystallized. The purified enzyme crystallized in two distinct forms that were grown by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant. Hexagonal crystals belonging to space group P3121 diffracted to 2.2,Å resolution, whereas orthorhombic crystals belonging to space group P212121 diffracted to 1.5,Å resolution. [source] Crystallization and preliminary X-ray diffraction analysis of salutaridine reductase from the opium poppy Papaver somniferumACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010Yasuhiro Higashi The opium poppy Papaver somniferum is the source of the narcotic analgesics morphine and codeine. Salutaridine reductase (SalR; EC 1.1.1.248) reduces the C-7 keto group of salutaridine to the C-7 (S)-hydroxyl group of salutaridinol in the biosynthetic pathway that leads to morphine in the opium poppy plant. P. somniferum SalR was overproduced in Escherichia coli and purified using cobalt-affinity and size-exclusion chromatography. Hexagonal crystals belonging to space group P6422 or P6222 were obtained using ammonium sulfate as precipitant and diffracted to a resolution of 1.9,Å. [source] Computer simulation study on propagation of nonlinear waves through heavily defective crystalsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004Y. Hiki Abstract A molecular dynamics computer simulation has been performed for a monatomic, anharmonic, and two-dimensional hexagonal crystal. Central forces between the nearest neighbor atoms and anharmonic forces up to the third order are considered. Pulse displacements are applied to the line of atoms at the left end of a rectangular model crystal, in the right half of which a number of light or heavy mass defects are randomly placed. Phonons or solitons propagating in the crystal and scattered by the defects are observed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Purification, crystallization and preliminary X-ray diffraction study of human ribosomal protein L10 core domainACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2007Mitsuhiro Nishimura Eukaryotic ribosomal protein L10 is an essential component of the large ribosomal subunit, which organizes the architecture of the aminoacyl-tRNA binding site. The human L10 protein is also called the QM protein and consists of 214 amino-acid residues. For crystallization, the L10 core domain (L10CD, Phe34,Glu182) was recombinantly expressed in Escherichia coli and purified to homogeneity. A hexagonal crystal of L10CD was obtained by the sitting-drop vapour-diffusion method. The L10CD crystal diffracted to 2.5,Å resolution and belongs to space group P3121 or P3221. [source] Magnetic-Field-Induced Growth of Single-Crystalline Fe3O4 Nanowires,ADVANCED MATERIALS, Issue 2 2004J. Wang Single-crystalline nanowires of Fe3O4 hydrothermally synthesized under a magnetic field are reported. The square and hexagonal crystals formed in zero applied field are shown to give way to nanowires as the magnetic field is increased. The Figure shows the situation for a 0.25,T field. The structure and magnetic properties are characterized by transmission electron microscopy, X-ray and electron diffraction, and magnetometry. [source] Al3BC3 Powder: Processing and Synthetic MechanismJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2009Sea-Hoon Lee The processing parameters for the synthesis of Al3BC3 powder were optimized, and the synthetic mechanism was investigated. The mechanical mixing of the raw powders promoted the formation of secondary phases due to mechanical alloying effect and contamination. Nearly X-ray pure Al3BC3 powder was obtained after the calcination of the raw powder mixture at 1800°C for 2 h in Ar by suppressing the vaporization of aluminum. During calcination, Al4C3 layer was formed at the surface of aluminum powder by the reaction with carbon, which maintained the morphology of the aluminum powder above its melting temperature. The nucleation and growth of Al3BC3 within aluminum melt began to occur at 1000°C, and became the main synthetic mechanism of Al3BC3 at 1100°C. The Al3BC3 particles synthesized at 1100°C were porous and were composed of fine hexagonal crystals. The main synthetic mechanism of A3BC3 changed into solid,solid reaction above 1100°C, and a gas,solid reaction promoted the densification of the porous Al3BC3 powder above 1340°C. [source] A symmetrical indexing scheme for decagonal quasicrystals analogous to Miller,Bravais indexing of hexagonal crystalsACTA CRYSTALLOGRAPHICA SECTION A, Issue 1 2007S. Ranganathan The problems of redundancy and superfluous indices in indexing the planes and axes in a decagonal quasicrystal are considered, using a scheme of five coplanar vectors in the quasiperiodic plane and one perpendicular vector. Of all the indexing schemes in use, this scheme offers the maximum advantage. An analogy is drawn to the hexagonal system using Miller,Bravais indices. Based on this, a symmetry-based indexing system for decagonal phases is devised that follows a simplified approximate zone law analogous to the exact zone law for the hexagonal case. The indices based on this scheme will be designated as `Frank indices'. High-symmetry electron diffraction zone-axis patterns as well as powder X-ray diffraction patterns are indexed using Frank indices and compared with those of other indexing schemes. [source] Crystallization and preliminary crystallographic analysis of a novel haemolytic lectin from the mushroom Laetiporus sulphureusACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2004José M. Mancheño The novel haemolytic lectin from the parasitic mushroom Laetiporus sulphureus (LSL) is a homotetramer (,140,kDa) composed of subunits associated by non-covalent bonds. It exhibits haemagglutination and haemolytic activities, both of which are inhibited by N -acetyllactosamine. The structural similarity found between LSL and the bacterial pore-forming toxins mosquitocidal toxin (MTX2) from Bacillus sphaericus and ,-toxin from Clostridium septicum points to a mechanism of biological action involving the formation of pores in the target membranes. LSL has been crystallized using the hanging-drop vapour-diffusion method at 291,K. Diffraction-quality hexagonal crystals have unit-cell parameters a = b = 101.8, c = 193.9,Å and belong to space group P6322. A 2.7,Å native data set was collected with an Rmerge of 9.2%. [source] Crystallization and X-ray diffraction analysis of peroxisomal ,3 -,2 -enoyl-CoA isomerase from Saccharomyces cerevisiaeACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2000Anu M. Mursula The purification, crystallization and X-ray diffraction analysis of Saccharomyces cerevisiae,3 -,2 -enoyl-CoA isomerase is described. ,3 -,2 -Enoyl-CoA isomerase is a member of the hydratase/isomerase protein family and is an auxiliary enzyme required for the ,-oxidation of unsaturated fatty acids. It is a hexameric enzyme consisting of six identical 32,kDa subunits of 280 residues each. In crystallization trials three crystal forms were obtained, with tetragonal and hexagonal lattices. A 2.5,Å data set was collected from the unliganded hexagonal crystals with an Rmerge of 6.6%. The crystal, with unit-cell parameters a = 116.0, b = 116.0, c = 122.9,Å, is likely to have P6322 symmetry. [source] | |||||||||||||