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791.
SALON Jozef 《中国科学:化学》2010,(1)
The selenium derivatization of nucleic acids is a novel and promising strategy for 3D structure determination of nucleic acids.Selenium can serve as an excellent anomalous scattering center to solve the phase problem,which is one of the two major bottlenecks in macromolecule X-ray crystallography.The other major bottleneck is crystallization.It has been demonstrated that the incorporated selenium functionality at the 2′-positions of the nucleosides and nucleotides is stable and does not cause significant st... 相似文献
792.
793.
Ohne Zusammenfassung 相似文献
794.
August Fuchs 《Monatshefte für Chemie / Chemical Monthly》1922,43(3):129-137
Ohne Zusammenfassung 相似文献
795.
796.
797.
Ivan Poto
k Jn Imrich Ivan Danihel Jozef Koíek Karel Douglas Klika 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(2):o87-o92
Two methyl derivatives, five‐membered methyl 2‐{2‐[2‐(9,10‐dihydroacridin‐9‐ylidene)‐1‐methylhydrazinyl]‐4‐oxo‐4,5‐dihydro‐1,3‐thiazol‐5‐ylidene}acetate, C20H16N4O3S, (I), and six‐membered 2‐[2‐(9,10‐dihydroacridin‐9‐ylidene)‐1‐methylhydrazinyl]‐4H‐1,3‐thiazin‐4‐one, C18H14N4OS, (II), were prepared by the reaction of the N‐methyl derivative of 4‐(9,10‐dihydroacridin‐9‐ylidene)thiosemicarbazide, C14H12N4S, (III), with dimethyl acetylenedicarboxylate and methyl propiolate, respectively. The crystal structures of (I), (II) and (III) are molecular and can be considered in two parts: (i) the nearly planar acridine moiety and (ii) the singular heterocyclic ring portion [thiazolidine for (I) and thiazine for (II)] including the linking amine and imine N atoms and the methyl C atom, or the full side chain in the case of (III). The structures of (I) and (II) are stabilized by N—H...O hydrogen bonds and different π–π interactions between acridine moieties and thiazolidine and thiazine rings, respectively. 相似文献
798.
Peter Segl’a Jozef Miklovič Dušan Mikloš Viera Mrázová Lenka Krupková Daniela Hudecová Zuzana Ondrušová Jozef Švorec Ján Moncol Milan Melník 《Transition Metal Chemistry》2009,34(1):15-22
The synthesis and characterization of six new 2-methylthionicotinate (2-MeSnic) copper(II) monomeric complexes [Cu(2-MeSnic)2L2] (L is furo[3,2-c]pyridine—fpy, 2-methylfuro[3,2-c]pyridine—Mefpy, 2,3-dimethylfuro[3,2-c]pyridine—Me2fpy or benzo[4,5]furo[3,2-c]pyridine—Bfp), [Cu(2-MeSnic)2(fpy)2(H2O)], as well as [Cu(2-MeSnic)2(CF3Phfpy)2(H2O)2] (CF3Phfpy is 2-(3-trifluoromethylphenyl)furo[3,2-c]pyridine) are reported. The characterizations were based on elemental analysis,
infrared, electronic and EPR spectra. The crystal structure of one of the complexes has been determined. The CuII atoms of [Cu(2-MeSnic)2(fpy)2(H2O)] are six-coordinated in a highly distorted tetragonal–bipyramidal arrangement by two nitrogen atoms, one from each fpy,
in trans-positions, by three oxygen atoms of the carboxyl groups of 2-MeSnic ligands (one monodentate, one asymmetrically bidentate),
one axial position being occupied by the oxygen of a water molecule. The antimicrobial effects have been tested on various
strains of bacteria, yeasts and filamentous fungi. A comparison of the IC50 and MIC values has shown a decrease of inhibition activities of tested compounds in the order: [Cu(2-MeSnic)2(Bfp)2] > Bfp > [Cu(2-MeSnic)2(CF3Phfpy)2(H2O)2] > [Cu(2-MeSnic)2(Me2fpy)2] > CF3Phfpy > [Cu(2-MeSnic)2(Mefpy)2] > Me2fpy > [Cu(2-MeSnic)2(fpy)2(H2O)] > [Cu(2-MeSnic)2(H2O)]2 > Mefpy > fpy = 2-MeSnicH = CuSO4.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
799.
Aleš Hrdlička Linda Zaorálková Michaela Galiová Tereza Čtvrtníčková Viktor Kanický Vítězslav Otruba Karel Novotný Pavel Krásenský Jozef Kaiser Radomír Malina Kateřina Páleníková 《Spectrochimica Acta Part B: Atomic Spectroscopy》2009
An acoustic signal was used for the internal standardization of laser-induced breakdown spectroscopy (LIBS) of a glazed wall tile. For the LIBS analyses, 1064 nm and 532 nm wavelengths of the Nd:YAG laser were utilized. The tile was depth profiled by a single-spot ablation from the glaze into the substrate. Some lines of major elements Si(I) 252.418, Si(I) 252.851, Al(I) 257.509, Cr(I) 295.368, Al(I) 309.271 nm and Ti(II) 334.904 nm were monitored. The decrease in the optical emissions during the ablation was successfully compensated for by normalization to the square power of the acoustic signal in the interval of 290–340 nm. This approach failed for the lines between 250–270 nm. The results were the same for both lasing wavelengths despite different irradiances. The acquired profiles are in good agreement with the reference X-ray fluorescence measurement. 相似文献
800.
Eva Hrabárová Jozef Rychlý Vlasta Sasinková Katarína Valachová Ivica Janigová Katarína Csomorová Ivo Juránek Ladislav Šoltés 《Cellulose (London, England)》2012,19(6):2093-2104
Fourier-transform infrared spectroscopy and non-isothermal methods—chemiluminometry, differential scanning calorimetry, and differential thermogravimetry—were used to characterize potential structural changes of thiol-modified hyaluronans. Degradative conditions tested via rotational viscometry were first initiated applying oxidative Weissberger’s system in a reaction system under aerobic conditions. Several low-molecular-weight thiol compounds—cysteamine, l-cysteine, and N-acetyl-l-cysteine—were subsequently tested for their potential antioxidative effects against hyaluronan degradation. It was shown that different final values of dynamic viscosity of hyaluronan solutions were dependent on the thiol structure and its initial concentration. An idea has been put forward that together with the reduction of the hyaluronan molecular weight, which is a consequence of fragmentation, the degradation products might contain associated or even cross-linked structures. In the case of N-acetyl-l-cysteine application, the carbonaceous residue evidenced by differential thermogravimetry was increased when compared to that of intact hyaluronan. 相似文献