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1.
Europium (Eu+) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu+ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal
was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal
amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions.
The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both
experimentally and theoretically. 相似文献
2.
3.
V. Yu. Fedorenko R. N. Baryshnikov B. I. Khairutdinov R. M. Vafina Yu. G. Shtyrlin V. V. Klochkov E. N. Klimovitskii 《Russian Journal of Organic Chemistry》2005,41(2):293-297
4-R-3,5-Dioxabicyclo[5.1.0]octanes were prepared in good yields by reduction of the corresponding 8,8-dichloro derivatives in a system Li-t-BuOH. According to the data of dynamic 1H and 13CNMR spectroscopy involving experiments in the NOESY mode the formal (R = H) at −93°C in (CD3)2CO exists in nearly equally occupied chair forms with endo- and exo-oriented three-membered ring. The like structure were found in the diastereomeric 4-Me(t-Bu)-analogs. The characteristic feature of 13C NMR spectra consists in considerable difference in the chemical shifts of the C8 atoms (Δδ∼16–17 ppm). The data on epimerization of diastereomers and calculations along AM1 procedure suggest for formal a three-component equilibrium including a twist-form.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 301–305.Original Russian Text Copyright © 2005 by Fedorenko, Baryshnikov, Khairutdinov, Vafina, Shtyrlin, Klochkov, Klimovitskii. 相似文献
4.
Zhu L Ostash B Rix U Nur-E-Alam M Mayers A Luzhetskyy A Mendez C Salas JA Bechthold A Fedorenko V Rohr J 《The Journal of organic chemistry》2005,70(2):631-638
The angucycline antibiotic family of the landomycins displays potent antitumor activity. To elucidate early post polyketide synthase (PKS) tailoring steps of the landomycin E biosynthetic pathway in Streptomyces globisporus 1912, the mutant S. globisporus M12 was prepared through gene replacement experiment of lndM2. It encodes an enzyme with putative oxygenase and reductase domains, according to sequencing of the gene and its counterpart lanM2 from S. cyanogenus S136 landomycin A biosynthetic gene cluster. The isolation of the novel shunt products 11-hydroxytetrangomycin and 4-hydroxytetrangomycin along with the well-known angucyclines tetrangomycin and tetrangulol from the culture of S. globisporus M12 provides evidence for the involvement of lndM2 in the early biosynthetic pathway of the landomycins, in particular in the formation of the alicyclic 6-hydroxy function of the landomycin aglycon. We therefore propose LndM2 to be responsible for both hydroxylation of the 6-position and its subsequent reduction. These reactions are necessary before the glycosylation reactions can occur. The results are in agreement with the originally published structure of landomycin but do not support the recently suggested revised structure. 相似文献
5.
6.
Ostash B Rix U Rix LL Liu T Lombo F Luzhetskyy A Gromyko O Wang C Braña AF Méndez C Salas JA Fedorenko V Rohr J 《Chemistry & biology》2004,11(4):547-555
A 3 kb DNA fragment from the Streptomyces globisporus 1912 landomycin E (LaE) biosynthetic gene cluster (lnd) was completely sequenced. Three open reading frames were identified, lndGT4, lndZ4, and lndZ5, whose probable translation products resemble a glycosyltransferase, a reductase, and a hydroxylase, respectively. Studies of generated mutants from disruption and complementation experiments involving the lndGT4 gene allowed us to determine that LndGT4 controls the terminal L-rhodinose sugar attachment during LaE biosynthesis and that LndZ4/LndZ5 are responsible for the unique C11-hydroxylation of the landomycins. Generation of the novel landomycins F, G, and H in the course of these studies provided evidence for the flexibility of lnd glycosyltransferases toward their acceptor substrates and a basis for initial structure-activity relationships within the landomycin family of antibiotics. 相似文献
7.
B. V. Bukvetskii E. V. Fedorenko A. G. Mirochnik V. E. Karasev 《Journal of Structural Chemistry》2007,48(6):1148-1151
The crystal structure of boron difluoride 3-phenylthiopentane-2,4-dionate was determined. The relationship between the structure and luminescent properties is traced in the series of boron difluoride acetyl acetonates (acetyl acetonate, phenylacetyl acetonate, and phenylthioacetyl acetonate). The presence of the π stacking interactions in boron difluoride phenylthioacetyl acetonate crystals leads to increased intensity and bathochromic shift of the fluorescence band. 相似文献
8.
Yu. N. Kul’chin O. B. Vitrik A. Yu. Zhizhchenko A. G. Mirochnik E. V. Fedorenko 《Optics and Spectroscopy》2012,112(4):514-518
The optical properties of a new photorecording polymer based on 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2-dioxaborine have
been investigated. This material is found to change its absorption coefficient and refractive index in the visible range under
illumination with a wavelength λ = 405.9 nm. This circumstance makes it possible to record static holograms with a spatial
frequency up to 2500 lines/mm, a diffraction efficiency above 60%, and a lifetime more than 6 months. A dynamic change in
the effective refractive index of this material under 405.9-nm irradiation is found, due to which one can form control optical
elements of the light-light type with a modulation frequency up to 50 Hz in it. 相似文献
9.
B. I. Bairachnyi A. A. Fedorenko G. G. Tul’skii O. N. Borsuk B. B. Bairachnyi 《Russian Journal of Applied Chemistry》2013,86(7):1001-1005
Development directions of the sulfate method for manufacture of titanium dioxide are considered, and alternative solutions for improving its cost efficiency and ecological advisability are suggested. A high-efficiency technology for electrochemical synthesis of a strong reducing agent, Ti2(SO4)3·nH2O, used instead of waste iron and powdered aluminum is suggested. 相似文献
10.
Fedorenko A. D. Fomenko I. S. Gongola M. I. Pervukhina N. V. Kalinkin A. V. Nikolenko A. D. Gushchin A. L. 《Journal of Structural Chemistry》2021,62(10):1531-1542
Journal of Structural Chemistry - The structure of a binuclear niobium(IV) thiocyanate complex (Bu4N)4[Nb2(μ2-S2)2(NCS)8]·H2O (1·H2O) is studied by X-ray crystallography. Compound... 相似文献