Synchrotron X-ray diffraction

Sunde M, Serpell LC, Bartlam M, Fraser PE, Pepys MB, Blake CC. Common core structure of amyloid fibrils by synchrotron X-ray diffraction. J Mol Biol 1997 273 729-739. 

The behavior of cristobalite PON has been studied as a function of pressure. No in situ evidence for pressure-induced amorphization was noticed. Whereas cristobalite Si02 displays four crystalline phases up to 50 GPa (195), PON remains in a cristobalite phase (193, 196). By using Raman spectroscopy and synchrotron X-ray diffraction, Kingma et al. (193, 197) observe a displacive transformation below 20 GPa to a high-pressure cristobalite-related structure, which then remains stable to at least 70 GPa. The high value of the calculated bulk modulus (71 GPa) (196) is indicative of the remarkable stiffness of the phase. 

Stolz, M., Stoffler, D., Aebi, U., and Goldsbury, C. (2000). Monitoring biomolecular interactions by time-lapse atomic force microscopy. / Struct. Biol. 131, 171-180. Sunde, M., Serpell, L. C., Bartlam, M., Fraser, P. E., Pepys, M. B., and Blake, C. C. (1997). Common core structure of amyloid fibrils by synchrotron X-ray diffraction. / Mol. Biol. 273, 729-739. 

The complexity of the solvable structure strongly depends on the spectral resolution of the diffraction method in use. Structures with about 60 atoms in the asymmetric unit were solved from powder data combining synchrotron X-ray diffraction with refinement from neutron diffraction data from the same material (Morris et al. 1994 Admans 2000). About half of that complexity can be achieved with good laboratory X-ray diffractometers (Masciocchi et al. 1996 Kariuki et al. 1999). Neutron diffraction data can better be used for structure refinement than for structure determination, for the same reason. 

Table 2.1 shows the crystal structure data of the phases existing in the Mg-H system. Pnre Mg has a hexagonal crystal structure and its hydride has a tetragonal lattice nnit cell (rutile type). The low-pressure MgH is commonly designated as P-MgH in order to differentiate it from its high-pressure polymorph, which will be discussed later. Figure 2.2 shows the crystal structure of p-MgH where the positions of Mg and H atoms are clearly discerned. Precise measurements of the lattice parameters of p-MgH by synchrotron X-ray diffraction yielded a = 0.45180(6) mn and c = 0.30211(4) nm [2]. The powder diffraction file JCPDS 12-0697 lists a = 0.4517 nm and c = 0.30205 nm. The density of MgH is 1.45 g/cm [3]. 

T. Noritake, S. Towata, M. Aoki, Y. Seno, Y. Hirose, E. Nishibori, M. Takata, M. Sakata, Charge density measurement in MgH by synchrotron X-ray diffraction, J. Alloys Compd. 356-357 (2003) 84-86. 

J.P. Maehlen, V.A. Yartys, R.V. Denys, M. Fichtner, C. Frommen, B.M. Bulychev, P. Pattison, H. Emerich, Y.E. EiUnchuk, D. Chernyshov, Thermal decomposition of AlH by in situ synchrotron X-ray diffraction and thermal desorption spectroscopy, J. Alloys Compd 446-447 (2007) 280-289. 

Dynamic circular motion of the metal atoms within La2 CgQ the cage has been investigated by NMR spectroscopy [77, 84, 85]. Synchrotron X-ray diffraction,... 

Microscopic time-resolved measurements of the hydrate phase during gas hydrate formation, decomposition, and inhibition began only in the mid-1990s. These techniques include in situ synchrotron x-ray diffraction (Koh et al., 1996 Klapproth et al., 2003 Uchida et al., 2003), neutron diffraction (Henning et al., 2000 Koh et al., 2000 Halpern et al., 2001 Staykova et al., 2003), Raman spectroscopy (Subramanian and Sloan, 2002 Komai et al., 2004), and NMR spectroscopy (Moudrakovski et al., 2001 Kini et al., 2004 Gupta et al., 2007). 

In this chapter, we provide an overview of our recent efforts to develop a fundamental science base for the design and preparation of optimal lipid-based carriers of DNA and siRNA for gene therapy and gene silencing. We employ synthesis of custom multivalent lipids, synchrotron X-ray diffraction (XRD) techniques, optical and cryo-electron microscopy, as well as biological assays in order to correlate the structures, chemical, and biophysical properties of cationic liposome (CL)-NA complexes to their biological activity and to clarify the interactions between CL-NA complexes and cellular components. Earlier work has been reviewed elsewhere [1-7] and will not be covered exhaustively here. 

CL-DNA complexes form spontaneously when solutions of cationic liposomes (typically containing both a cationic lipid and a neutral helper lipid) are combined. We have discovered several distinct nanoscale structures of CL-DNA complexes by synchrotron X-ray diffraction, three of which are schematically shown in Fig. 1. These are the prevalent lamellar phase with DNA sandwiched between cationic membranes (Lo,c) [22], the inverted hexagonal phase with DNA encapsulated within inverse lipid tubes (Hnc) [23], and the more recently discovered Hj0 phase with hexagonally arranged rod-like micelles surrounded by DNA chains forming a continuous substructure with honeycomb symmetry [24]. Both the neutral lipid and the cationic lipid can drive the formation of specific structures of CL-DNA complexes. The inverse cone shape of DOPE favors formation of the... 

Safinya CR, Koltover I (1999) Self assembled structures of lipid-DNA nonviral gene delivery systems from synchrotron X-ray diffraction. In Huang L, Hung M-C, Wagner E (eds) Nonviral vectors for gene therapy. Academic, San Diego... 

The formation of the Al-0 complexes in the sodalite cages of zeolite Y is analagous to similar La-0 complexes previously described (15,16). These phenomena are under study with neutron- and synchrotron-X-ray diffraction. 

The present work summarizes opportunities of using high-resolution synchrotron and standard xrd techniques for structural characterization as well as for investigations of structure-property-relationships. xrd will be used to determine quantitatively the phase content of morphotropic pzt. Temperature dependent measurements provide information about the phase transformation of morphotropic donor doped pzt ceramics and high-resolution synchrotron X-ray diffraction gives information about the extrinsic and intrinsic contributions to the electric field induced strain, xrd results are finally compared with electrical measurements to analyze the interactions among microstructure, phase content and properties. 

Up to 1999, only metal atoms [1-5], metal clusters [6,7], metal nitrides [55-57], and noble gas atoms [58-60] were observed to be encaged inside C60, C70, or various sizes of higher fullerenes. The experimental evidence for carbon atoms or metal-carbon compounds (carbides) being encapsulated inside fullerenes had not yet been observed. In 2000, Shinohara et al. succeeded in the first production, isolation, and spectroscopic characterization of a scandium carbide endohedral fullerene (Sc2C2) C84. Following this, the first experimental evidence based on synchrotron X-ray diffraction was presented and revealed that the Sc carbide is encapsulated in the form of a lozenge-shaped Sc2C2 cluster inside the D2d-C84 fullerene [8]. 

Inspection of the synchrotron X-ray diffraction profiles of Sm2 75C60 readily reveals the appearance of superlattice peaks at low angles that index to the enlarged... 

Figure 22.6. (A) Temperature variation profile during, and (B) three-dimensional plots of the results obtained from, a time-resolved synchrotron X-ray diffraction experiment on SOS (1,3-distearoyl-2-oleoyl-.sn-glycerol) without annealing, a and (3 polymorphic forms LC1 liquid crystalline structure 1. (Reproduced with permission from Sato et al., 1999.)...

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