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81.
D.L. Nagy L. Bottyán L. Deák E. Szilágyi H. Spiering J. Dekoster G. Langouche 《Hyperfine Interactions》2000,126(1-4):353-361
Grazing incidence nuclear resonant scattering of synchrotron radiation can be applied to perform depth-selective phase analysis
and to determine the isotopic and magnetic structure of thin films and multilayers. Principles and recent experiments of this
new kind of reflectometry are briefly reviewed. Methodological aspects are discussed. Model calculations demonstrate how the
orientations of the sublattice magnetisation in ferro- and antiferromagnetic multilayers affect time-integral and time-differential
spectra. Experimental examples show the efficiency of the method in investigating finite-stacking, in-plane and out-of-plane
anisotropy and spin-flop effects in magnetic multilayers.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
82.
Lszl Ktai KalyanK. Banerji Istvn Saj Jnos Kristf B. Sreedhar Sndor Holly Gbor Keresztury Antal Rockenbauer 《Helvetica chimica acta》2002,85(8):2316-2327
Tetraamminecopper(2+) bis(permanganate) ([Cu(NH3)4](MnO4)2; 1 ) was prepared, and its properties were studied in both aqueous solution and the solid phase. The presence of H‐bond interactions between the ammonia ligand of the complex cation and an O‐atom of the permanganate ion was detected by IR and Raman methods. The solid‐phase thermal deammoniation of 1 led to an unusual intramolecular redox reaction between the Mn O⋅⋅⋅H N linkage with formation of NH4NO3 and CuMn2O4‐type mixed oxides instead of stepwise deammoniation, even below 100°. The thermal deammoniation of 1 in aqueous solution led, instead of to hydrated copper(2+) bis(permanganate), to the formation of NH4MnO4 ( 2 ). Since the temperature of the thermal deammoniation of 1 is lower than the decomposition temperature of the permanganate ion, the regulated solid‐phase decomposition of 1 allowed preparation of CuMn2O4‐type oxides with mixing of copper and manganese at the atomic level. 相似文献
83.
A highly efficient trifluoromethanesulfonic acid-mediated rearrangement of the benzoylaminomethylthio group of 3-benzoylaminomethylthioindoles (7a-e) to position 2 of the indole ring was developed. Thus, 2-benzoylaminomethylthioindoles (9a-e) were obtained in good yields and were involved as key intermediates in the synthesis of the new γ-carboline analogue ring system: 2,9-dihydro-4-aryl-1,3-thiazino[6,5-b]indole derivatives (11a-e). The target thiazinoindoles (11a-e) were prepared via 2-thiobenzoylaminomethylindoles (10a-e) in modified Bischler-Napieralski reactions. 相似文献
84.
The retention of enantiomers of chiral analytes, i.e. alpha-substituted glycine analogs, on a quinine-based anion-exchanger chiral stationary phase was studied in the temperature range of 5-70 degrees C and at different mobile phase compositions, using isocratic elution in the reversed-phase mode. By variation of both mobile phase composition and temperature, baseline separations could be achieved for these enantiomers. Separation could be optimized more quickly by adjusting the column temperature rather than the mobile phase composition. The dependence of the natural logarithms of retention and selectivity factors (lnk' and lnalpha) on the inverse of temperature, 1/T (van't Hoff plots) was used to determine thermodynamic data on the enantiomers. Calculated thermodynamic constants (Delta(DeltaH degrees ), Delta(DeltaS degrees ) and Delta(DeltaG degrees )) were applied to promote an understanding of the thermodynamic driving forces for retention in this chromatographic system. The elution sequence of the enantiomers in most cases was determined. 相似文献
85.
Károlyi BI Bösze S Orbán E Sohár P Drahos L Gál E Csámpai A 《Molecules (Basel, Switzerland)》2012,17(3):2316-2329
A series of novel functionalized mono-, bis- and tris-(S)-{[(2S,4R,8R)-8-ethyl-quinuclidin-2-yl](6-methoxyquinolin-4-yl)}methanamines including ferrocene-containing derivatives was obtained by the reaction of the precursor amine with a variety of acylation agents. Their in vitro antitumor activity was investigated against human leukemia (HL-60), human neuroblastoma (SH-SY5Y), human hepatoma (HepG2) and human breast cancer (MCF-7) cells by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-assay and the 50% inhibitory concentration (IC(50)) values were determined. Our data indicate that the precursor amine has no antitumor activity in vitro, but the bis-methanamines with ureido-, thioureido and amide-type linkers display attractive in vitro cytotoxicity and cytostatic effects on HL-60, HepG2, MCF-7 and SH-SY5Y cells. Besides 1H- and 13C-NMR methods the structures of the new model compounds were also studied by DFT calculations. 相似文献
86.
ortho-Nitrophenyl-substituted condensed 1,3-benzothiazines proved to be a useful core unit in indole syntheses under non-reductive conditions. Thus, the treatment of ortho-nitro-2-aryl-2a-chloro-4H-azeto[2,1-b][1,3]benzothiazin-1-ones with sodium methoxide in methanol provided indolo-1,4-benzothiazepines via a novel rearrangement. Through the sulfur extrusion reaction of indolo[2,3-b][1,4]benzothiazepines, further alkaloid-type indole derivatives, indolo[3,2-c]isoquinolines, were obtained. The structures of the new ring systems were determined by means of NMR spectroscopy. 相似文献
87.
L de Lichtervelde CE Antal AE Boitano Y Wang P Krastel F Petersen AC Newton MP Cooke PG Schultz 《Chemistry & biology》2012,19(8):994-1000
To identify small molecules that selectively control hematopoietic stem cell differentiation, we performed an unbiased screen using primary human CD34(+) cells. We identified a plant-derived natural product, euphohelioscopin A, capable of selectively differentiating CD34(+) cells down the granulocyte/monocytic lineage. Euphohelioscopin A also inhibits proliferation and induces differentiation of the myeloid leukemia cell lines THP-1 and HL-60. Mechanistic studies revealed that euphohelioscopin A is an activator of protein kinase C (PKC), and that the promonocytic effects of this natural product are mediated by PKC activation. In addition to shedding insights into normal hematopoiesis, this work may ultimately facilitate the application of stem cell therapies to a host of myeloid dysfunctions. 相似文献
88.
Viktor Háda Antal Tungler László Szepesy 《Reaction Kinetics and Catalysis Letters》2001,73(1):109-115
High diastereoselectivities were obtained in the heterogeneous catalytic hydrogenation of chiral pyrrole and pyridine derivatives with complete conversion, in non-acidic medium. The products of the hydrogenations, secondary and tertiary amines act as catalyst modifiers, increasing the d.e. values in the last period of the reactions. 相似文献
89.
Szilágyi Imre Miklós Kállay-Menyhárd Alfréd 《Journal of Thermal Analysis and Calorimetry》2019,135(6):2915-2915
Journal of Thermal Analysis and Calorimetry - 相似文献
90.
Bakos J. S. Földes I. B. Hevesi I. Kovács J. Nánai L. Szil E. 《Applied Physics A: Materials Science & Processing》1985,37(4):247-249
New experimental results concerning the nonlinear absorption of V2O5 single crystals are reported. A Q-switched ruby laser have been used to measure the two-photon absorption coefficient at 694.3 nm. The results are analysed and interpreted with respect to the second-order attenuation of the light propagating through a plane-parallel medium. 相似文献