Notizen: The Crystal Structure of MnIn2Se4, a Ternary Layered Semiconductor

Single crystals of MnIn2Se4 have been grown by the chemical vapour phase transport technique using AlCl3 as the transporting agent. The structure was refined to R = 0.064, Rw, = 0.059 for 609 reflections. MnIn2Se4 (R 3̄m, hexagonal axes a = 4.051(1), c = 39.464(2) Å, c/a = 9.74, Z = 3) crystallizes with a nearly close-packed layered structure (sequence of the Se layers ABCA|CABC|BCAB) with Moct (= 0.56 Mn + 0.44 In) in octahedral coordination (Moct,–Se = 6 × 2.721(1) A) and Mtet (= 0.78 In + 0.22 Mn) in tetrahedral coordination (Mtet-Se = 1 × 2.527(2) and 3 × 2.593(1) Å). The overall layer sequences is ΑβΒαCyA| Cα AγBβC| BγCβAα B.

Analytical TEM study of annealed nanocrystalline cobalt-phosphorous electrodeposits

Investigation of thermal stability of two nanocrystalline Co-P alloys shows that P atoms segregate to the grain boundaries upon annealing until precipitation of Co(2)P and CoP precipitates takes place. The P-rich precipitates formed have been investigated by analytical transmission electron microscopy to obtain statistical results of precipitate size, volume fraction and spatial distribution. Electron spectroscopic imaging maps show that the P-rich precipitates are 33 +/- 9 nm in Co-1.1at.%P and 33 +/- 12 nm in Co-3.2at.%P. The main differences between the alloys are the precipitate size distribution (Co-3.2at.%P having broader distribution) and precipitate volume number density (Co-3.2at.%P has 1.8 times more precipitates than Co-1.1at.%P). The volume fraction of precipitates is 3.0% in Co-1.1at.%P and 4.4% in Co-1.1at.%P. Most of the precipitates are of nearly spherical or slightly elongated shape, and only a few have a platelet-like shape as expected from previous tomographic atom probe measurements. Due to the truncation and projection effects, the composition of the precipitates could not be determined.

EBSD characterization of carbide-carbide boundaries in WC-Co composites

A sample of WC-6wt%Co was investigated for grain boundary character distribution and occurrence of coincidence site lattice (CSL) boundaries on a statistical basis. For this purpose orientation measurements of the grains were carried out using electron back-scattered diffraction (EBSD). The dominant misorientation relationships were determined by complementary EBSD data representation tools such as orientation maps, misorientation angle distribution histograms and the sectioned three-dimensional misorientation space. It was found that the grain boundary character distribution of the material is nearly random and the CSL boundaries are not present in statistically significant amounts. It was also found that the amount of binder phase does not play a role in the formation of special boundaries. The paper focuses on the methodology of characterizing grain boundaries in a hexagonal material using EBSD.

Cognitive and affective disturbances in multiple sclerosis

The emotional and relationship problems associated with MS have not always been fully appreciated by the medical profession, which has tended to concentrate on the physical aspects of this disease. Yet the psychological problems of MS often cause more suffering than physical effects.

Aqua[1-(2,6-dichloro-4-hydroxyphenyl)-2- phenylethylenediamine]sulfatoplatinum(II) complexes with variable substituents in the 2-phenyl ring, II: Correlation of molecular structure and estrogenic activity of breast and prostate cancer inhibiting. [erythro-1-(2,6-dichloro-4-hydroxyphenyl)-2-(2-halo-4- hydroxyphenyl)ethylenediamine]platinum(II) complexes

Complete three-dimensional X-ray crystal structure analyses of estrogenic [erythro-1-(2,6-dichloro-4-hydroxyphenyl)-2-(2-halo-4- hydroxyphenyl)ethylenediamine]diiodoplatinum(II) complexes (halo = fluoro:erythro-8PtI2 and halo = chloro:erythro-9-PtI2) which were synthesized for application in breast and prostate cancer, have been carried out. 6239 as well as 6521 reflexes were measured and refined to an R-value of 0.105 and 0.066, respectively. The molecules of erythro-8-PtI2 are displaced laterally from a possible Pt-Pt-axis separated, alternatingly, by Pt-Pt-distances of 3.62 A and 6.27 A. A comparable structure possesses erythro-9-PtI2 with Pt-Pt-distances of 3.59 A and 6.32 A. The ethylenediamine ligands of erythro-8-PtI2 and erythro-9-PtI2 are puckered and exist in half chair conformations. For both complexes the 2,6-dichloro-4-hydroxyphenyl ring is equatorially arranged, while the 2-halo-4-hydroxyphenyl ring is nearly perpendicular to the N-Pt-N plane. The O-O-distance between the phenolic oxygens amounts to 8.1 A in erythro-8-PtI2 and to 7.8 A in erythro-9-PtI2. Though these O-O-distances differ strongly from that (12.1 A), which is considered to be necessary for the binding of an estrogen to its receptor, [1-(2,6-dichloro-4-hydroxyphenyl)- 2-(2-halo-4-hydroxyphenyl)ethylenediamine)]platinum(II) complexes show estrogenic effects which are, however, strongly reduced compared to that of therapeutically used estrogens like diethylstilbestrol. The relationship between molecular structure and estrogenicity as well as the significance of the latter for antitumor activity and untoward side effects are thoroughly discussed.