X-ray diffraction experiment on DyBr3:20H2O and YbBr3:20H2O solutions. Pre-main peak as a prerequisite to consider the structural organization of solutions

2008 ◽  
Vol 49 (5) ◽  
pp. 950-952
Author(s):  
O. V. Grechin ◽  
V. V. Kuznetsov ◽  
M. V. Yakimova
Keyword(s):  
Structural Organization ◽  
Main Peak ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Silicate-germanate K2Y[(Si3Ge)O10(OH)] with unusual complex corrugated layer and its correlation to ring silicate gerenite and chain silicate chkalovite

2020 ◽  
Vol 235 (4-5) ◽  
pp. 167-172
Author(s):  
Anastasiia P. Topnikova ◽  
Elena L. Belokoneva ◽  
Olga V. Dimitrova ◽  
Anatoly S. Volkov ◽  
Leokadiya V. Zorina
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Complex Anion ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Chain Silicate ◽  
Novel Complex

AbstractA new silicate-germanate K2Y[(Si3Ge)O10(OH)] was synthesized hydrothermally in a system Y2O3:GeO2:SiO2 = 1:1:2 (T = 280 °C; P = 90–100 atm.); K2CO3 was added to the solution as a mineralizer. Single-crystal X-ray diffraction experiment was carried out at low temperature (150 K). The unit cell parameters are a = 10.4975(4), b = 6.9567(2), c = 15.4001(6) Å, β = 104.894(4)°; V = 1086.86(7) Å3; space group is P 21/c. A novel complex anion is presented by corrugated (Si,Ge) tetrahedral layers connected by couples of YO6 octahedra into the mixed microporous framework with the channels along b and a axes, the maximal size of cross-section is ~5.6 Å. This structure has similarity with the two minerals: ring silicate gerenite (Ca,Na)2(Y,REE)3Si6O18 · 2H2O and chain silicate chkalovite Na2BeSi2O6. Six-member rings with 1̅ symmetry as in gerenite are distinguished in the new layer. They are mutually perpendicular to each other and connected by additional tetrahedra. Straight crossing chains in chkalovite change to zigzag four-link chains in the new silicate-germanate layer.

Disordered misfit [Ca2CoO3][CoO2]1.62 structure revisited via a new intrinsic modulation

2008 ◽  
Vol 64 (2) ◽  
pp. 144-153 ◽  
Author(s):  
Hervé Muguerra ◽  
Dominique Grebille ◽  
Françoise Bourée
Keyword(s):  
Electronic Structure ◽  
Single Crystal ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Neutron Diffraction Experiment ◽  
X Ray ◽  
Structural Modifications ◽  
Local Ordering ◽  
Powder Neutron Diffraction ◽  
Modulation Vector

The structure of the thermoelectric lamellar misfit cobalt oxide [Ca2CoO3][CoO2]1.62 was refined again using single-crystal X-ray diffraction data. A new commensurate intrinsic modulation was observed involving a modulation vector orthogonal to the misfit direction (⅔,0,−⅓). The five-dimensional superspace group is C2/m(1δ0)(α0γ)gm and the structure was solved using a commensurate approximation. A new model is given involving an occupation modulation of the split sites of the [CoO] layer. This [CoO] layer can be described by triple chains running along b. The residual disorder along b can then be explained by the assumption of a local ordering with two types of clusters: CoO2 and Co5O4. A powder neutron diffraction experiment confirmed the ordering evidenced by the single-crystal X-ray diffraction study, but was not sufficient by itself to deal with this double modulated scheme. The new intrinsic modulation is destroyed by partial metal substitutions in the [CoO] layer. The structural modifications of this layer directly influence the physical properties which are related to the electronic structure of the [CoO2] layers.

On the atomic interdiffusion in Co/Pt superlattices

1992 ◽  
Vol 7 (6) ◽  
pp. 1309-1312 ◽  
Author(s):  
X. Yan ◽  
T. Egami ◽  
E.E. Marinero ◽  
R.F.C. Farrow ◽  
C.H. Lee
Keyword(s):  
Minor Component ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Peaks ◽  
Large Width ◽  
A Minor ◽  
Component Parallel

We have performed x-ray diffraction experiments on MBE grown 〈111〉 and 〈001〉 oriented Co (3 Å)/Pt (18 Å) superlattices with the scattering vector Q covering a plane that includes a major component perpendicular and a minor component parallel to the plane of the sample. The superlattice diffraction peaks were found to have a large width parallel to the plane of the film, indicating that there is strong in-plane disorder. These broad peaks were integrated to evaluate more accurately the amount of interdiffusion at the interface, which was found to be similar in both films, contrary to what the conventional x-ray diffraction experiment suggests.

Four New Cytotoxic Arborinane-Type Triterpenes from the Endolichenic Fungus Myrothecium inundatum

Planta Medica ◽  
2019 ◽  
Vol 85 (09/10) ◽  
pp. 701-707 ◽  
Author(s):  
Buddha Bahadur Basnet ◽  
Li Liu ◽  
Baosong Chen ◽  
Yerlan Melsuly Suleimen ◽  
Haiyang Yu ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Ethyl Acetate Extract ◽  
Human Cancer ◽  
Diffraction Experiment ◽  
Human Cancer Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Cancer Cell Lines ◽  
Endolichenic Fungus ◽  
New Compounds

AbstractTwo new arborinane-type triterpenes, myrotheols A (1) and B (2), two new arborinane-type glycosides, myrothesides C (3) and D (4), together with four known diterpenes (5 – 8) were isolated from the ethyl acetate extract of the endolichenic fungus Myrothecium inundatum. The structures of new compounds 1 – 4 were elucidated by NMR and MS analyses. The absolute configuration of 1 was assigned by a single-crystal X-ray diffraction experiment. Compounds 3 and 4 represent the first two natural 4-O-methyl-α-D-mannosides. Compounds 1 – 8 exhibited cytotoxicity against K562 and RKO human cancer cell lines.

Synthesis and Photoluminescence of Amorphous Ca5Ge2O9 Nanowires

2008 ◽  
Vol 8 (12) ◽  
pp. 6376-6380 ◽  
Author(s):  
Meng-Yen Tsai ◽  
Chung-Yi Yu ◽  
Tsong-Pyng Perng
Keyword(s):  
Inductively Coupled Plasma ◽  
Vapor Condensation ◽  
Mass Spectrometric ◽  
Main Peak ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Inductively Coupled ◽  
Violet Luminescence ◽  
New Thinking

A new method to prepare amorphous Ca5Ge2O9 nanowires is demonstrated in the present study. Germanium nanoparticles with the size ranging from 10 to 50 nm were first prepared by a vapor condensation technique. Upon immersing the nanoparticles in Ca(OH)2 aqueous solution, hydrated Ca5Ge2O9 nanowires were formed rapidly. The phase was determined by X-ray diffraction, and the stoichiometry of Ca:Ge was further confirmed by energy-dispersive X-ray spectroscopic and inductively coupled plasma-mass spectrometric analyses. The diameter of nanowires varied from several tens to more than 100 nm, and the length increased with aging time up to the completion of reaction. After dehydrating at 400 °C, the nanowires became amorphous, and the stoichiometry of Ca:Ge remained unchanged. A blue-violet luminescence was detected from these amorphous nanowires. The emission band distributed from 300 to 550 nm, with the main peak locating at 380 nm. Ge-associated luminescence centers are proposed to be responsible for this emission. The formation of amorphous Ca5Ge2O9 nanowires may provide a new thinking to prepare other kinds of amorphous one-dimensional nanomaterials.

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