An improved r-factor algorithm for TVD schemes

2008 ◽  
Vol 51 (3-4) ◽  
pp. 610-617 ◽  
Author(s):  
Lian-xia Li ◽  
Hua-sheng Liao ◽  
Li-jian Qi
Keyword(s):  
1999 ◽  
Vol 23 (1) ◽  
pp. 14-15
Author(s):  
Ichiro Tanaka ◽  
Takashi Ohhara ◽  
Nobuo Niimura ◽  
Yuji Ohashi ◽  
Qian Jiang ◽  
...  

Neutron diffraction analysis of TaCp2(H)(SiMe2H)2 (1) has revealed a symmetric structure with a classical, rather than agostic, hydride ligand: the Ta–H distance is 1.785(15) Å, the non-bonding H···Si distances are 2.189(18) and 2.190(17) Å, and the H–Ta–Si angles are 55.2(5) and 55.5(5)°; final R factor = 8.9% for 1295 reflections.


2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Hyeongsub So ◽  
Ro Woon Lee ◽  
Sung Taek Hong ◽  
Kyou-Hyun Kim

AbstractWe investigate the sensitivity of symmetry quantification algorithms based on the profile R-factor (Rp) and the normalized cross-correlation (NCC) coefficient (γ). A DM (Digital Micrograph©) script embedded in the Gatan digital microscopy software is used to develop the symmetry quantification program. Using the Bloch method, a variety of CBED patterns are simulated and used to investigate the sensitivity of symmetry quantification algorithms. The quantification results show that two symmetry quantification coefficients are significantly sensitive to structural changes even for small strain values of < 1%.


1974 ◽  
Vol 52 (16) ◽  
pp. 2923-2927 ◽  
Author(s):  
André L. Beauchamp ◽  
Bernard Saperas ◽  
Roland Rivest

The compound cis-Hg(SCN)2(Phen)2 belongs to the triclinic space group [Formula: see text] with a = 13.252(5), b = 11.077(4), c = 8.443(3) Å, α = 105.20(3), β = 83.25 (3), γ = 90.92(3)°, and Z = 2. The structure was solved by the heavy atom method and refined on 1718 independent reflections to an R factor of 0.069. The crystal contains discrete molecules, in which mercury is coordinated to four nitrogen atoms from two phenanthroline molecules and to two sulfur atoms from thiocyanate groups. These donor atoms define a distorted octahedral geometry around mercury. The Hg—N bond lengths are in the range 2.42(2)–2.52(2) Å, whereas the Hg—S bonds are equal to 2.622(8) and 2.582(8) Å. The molecules are packed in layers parallel to the (110) planes and the layers are held together by normal van der Waals interactions. Within the layers, the packing of the complex is characterized by parallel stacking of phenanthroline ligands at distances of ∼3.4 Å. The terminal nitrogen atoms of the thiocyanate groups are uncoordinated.


1988 ◽  
Vol 16 (6) ◽  
pp. 949-953 ◽  
Author(s):  
JOHN P. PRIESTLE ◽  
HANS-PETER SCHÄR ◽  
MARKUS G. GRÜTTER

Summary The three-dimensional structure of human recombinant interleukin-1β has been determined at 0.24 nm resolution by X-ray crystallographic techniques. The partially refined model has a crystallographic R-factor of just under 19%. The structure is composed of 12 β-strands forming a complex network of hydrogen bonds. The core of the structure can best be described as a tetrahedron whose edges are each formed by two antiparallel β-strands. The interior of this structure is filled with hydrophobic side-chains. There is a 3-fold repeat in the folding of the polypeptide chain. Although this folding pattern suggests gene triplication, no significant internal sequence homology between topologically corresponding residues exists. The folding topology of interleukin-1β is very similar to that described by A. D. McLachlan [(1979) J. Mol. Biol. 133, 557–563] for soybean trypsin inhibitor.


1972 ◽  
Vol 20 (2) ◽  
pp. 239-252 ◽  
Author(s):  
J. M. Robertson ◽  
E. C. R. Reeve

SUMMARYThe resistance levels conferred by the T-determinants in four R-factors to Tetracycline and Minocycline in cells ofEscherichia coliK 12, before and after induction of maximum resistance by treatment with sub-inhibitory concentrations of the drugs, are measured by simple growth-and-challenge tests. The effect of a plasmid TKwhich confers tetracycline resistance on its hostKlebsiella aerogenesis tested in the same way. The five T-determinants fall into a high-level and a low-level group for resistance, the former giving 3- to 4-fold higher resistance in both induced and uninduced cells than the latter. The T-determinants all confer much lower resistance to Minocycline (a tetracycline molecule modified at the C-6 and C-7 positions) than to Tetracycline. The main cause of this difference is that cells carrying a T-determinant exclude Minocycline much less efficiently than Tetracycline, but in addition Minocycline is less effective than Tetracycline in inducing increased resistance. These results are discussed in the light of a model put forward to explain the inducible nature of R-factor resistance to the tetracyclines.


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