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381.
Andrej B. Arbuzov Renat R. Sadykov Zbigniew Wa̧s 《The European Physical Journal C - Particles and Fields》2013,73(11):1-18
Isolated lepton momenta, in particular their directions are the most precisely measured quantities in pp collisions at LHC. This offers opportunities for multitude of precision measurements. It is of practical importance to verify if precision measurements with leptons in the final state require all theoretical effects evaluated simultaneously or if QED bremsstrahlung in the final state can be separated without unwanted precision loss. Results for final-state bremsstrahlung in the decays of narrow resonances are obtained from the Feynman rules of QED in an unambiguous way and can be controlled with a very high precision. Also for resonances of non-negligible width, if calculations are appropriately performed, such separation from the remaining electroweak effects can be expected. Our paper is devoted to validation that final-state QED bremsstrahlung can indeed be separated from the rest of QCD and electroweak effects, in the production and decay of Z and W bosons, and to estimation of the resulting systematic error. The quantitative discussion is based on Monte Carlo programs PHOTOS and SANC, as well as on KKMC which is used for benchmark results. We show that for a large class of W and Z boson observables as used at LHC, the theoretical error on photonic bremsstrahlung is 0.1 or 0.2 %, depending on the program options used. An overall theoretical error on the QED final-state radiation, i.e. taking into account missing corrections due to pair emission and interference with initial state radiation is estimated respectively at 0.2 % or 0.3 % again depending on the program option used. 相似文献
382.
Jaroslav Galba Juraj Pieanský Andrej Kov
Dominika Oleov Ondrej Cehlr Martin Kertys Petr Kozlík Petra Chaov Barbora Tir
ov Kristin Slí Peter Miku 《Molecules (Basel, Switzerland)》2021,26(2)
Oxandrolone, a synthetic testosterone analog, is used for the treatment of several diseases associated with weight loss. Unfortunately, oxandrolone is abused by many athletes and bodybuilders due to its strong anabolic effect. We have developed and validated a highly sensitive and rapid on-line SPE-UHPLC-MS/MS method for the determination of oxandrolone and simultaneous identification of its major metabolite 17-epi-oxandrolone in urine matrices. Enrichment of the analytes via an integrated solid-phase extraction was achieved using an Acquity UPLC BEH C18 Column. Subsequently, the chromatographic separation of the on-line preconcentrated sample fraction was achieved using an Acquity HSS T3 C18 Column. For the structural identification of these analytes, a high-resolution mass spectrometer Synapt-G2Si coupled to the Acquity M-class nano-LC system with ionKey source was used. A highly sensitive determination of oxandrolone was achieved using a tandem quadrupole mass spectrometer XEVO TQD. The method was successfully validated in the linear range of oxandrolone from 81.63 pg·mL−1 (limit of quantification, LOQ) to 5000 pg·mL−1 in the human urine matrix. It was applied to the analysis of real urine samples obtained from a healthy volunteer after the oral administration of one dose (10 mg) of oxandrolone. Concentration vs. time dependence was tested in the time interval of 4 h–12 days (after oral administration) to demonstrate the ability of the method to detect the renal elimination of oxandrolone from the human body. Favorable performance parameters along with successful application indicate the usefulness of the proposed method for its routine use in antidoping control labs. 相似文献
383.
Vladimir V. Ivanov Alexandr A. Yurchenko Alexander N. Chernega Alexandr M. Pinchuk Andrej A. Tolmachev 《Heteroatom Chemistry》2002,13(1):84-92
A number of 4,5‐dihydrobenzo[e]imidazo[2,1‐c][1,4,2]diazaphosphinine derivatives were prepared by the direct phosphorylation of 1‐(4‐Chlorophenylcarboxamido)‐2‐(1H‐1‐imidazolyl)‐5‐trifluoromethylbenzene in basic medium with phosphorus(III) bromide and dibromophenylphosphine. The tricyclic compounds 6a, 6b , and 9 having a trivalent phosphorus atom undergo the diazaphosphinine ring opening upon treatment with secondary amines in the presence of sulfur. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:84–92, 2002; DOI 10.1002/hc.10000 相似文献
384.
Reiffová Katarína Podolonovičová Jana Oriňák Andrej Flórián Karol Gondová Tat’ána 《平面色谱法杂志一现代薄层色谱法》2003,16(1):52-57
JPC – Journal of Planar Chromatography – Modern TLC - A rapid, simple qualitative thin-layer chromatographic method has been developed for separation of mono- and fructooligosaccharides... 相似文献
385.
Jelka Šuštar-Vozlič Katja Rostohar Andrej Blejec Petra Kozjak Zoran Čergan Vladimir Meglič 《Analytical and bioanalytical chemistry》2010,396(6):2031-2041
In order to comply with the European Union regulatory threshold for the adventitious presence of genetically modified organisms
(GMOs) in food and feed, it is important to trace GMOs from the field. Appropriate sampling methods are needed to accurately
predict the presence of GMOs at the field level. A 2-year field experiment with two maize varieties differing in kernel colour
was conducted in Slovenia. Based on the results of data mining analyses and modelling, it was concluded that spatial relations
between the donor and receptor field were the most important factors influencing the distribution of outcrossing rate (OCR)
in the field. The approach for estimation fitting function parameters in the receptor (non-GM) field at two distances from
the donor (GM) field (10 and 25 m) for estimation of the OCR (GMO content) in the whole receptor field was developed. Different
sampling schemes were tested; a systematic random scheme in rows was proposed to be applied for sampling at the two distances
for the estimation of fitting function parameters for determination of OCR. The sampling approach had already been validated
with some other OCR data and was practically applied in the 2009 harvest in Poland. The developed approach can be used for
determination of the GMO presence at the field level and for making appropriate labelling decisions. The importance of this
approach lies in its possibility to also address other threshold levels beside the currently prescribed labelling threshold
of 0.9% for food and feed. 相似文献
386.
Andrej Oriňák Ivan Talian Evtim V. Efremov Freek Ariese Renata Oriáaková 《Chromatographia》2008,67(3-4):315-319
Hyphenation of thin layer chromatography (TLC) with surface-based spectral methods requires a homogeneous surface for direct
and quantitative analysis on the chromatographic plate after separation. Since most chromatographic materials do not produce
strong background signals in Raman spectroscopy (RS) or surface-enhanced RS (SERS), we tested the suitability of two different
chromatographic substrates and one interface for coupling SERS with TLC. This was carried out by using a chromatographic thin
layer, specially produced for RS measurements, and a monolithic silica thin layer. A typical TLC plate with a modified aluminium
backplate foil on one side was used as an interface. Three biologically active diterpenes, namely gibberellic acid (GA), abietic
acid (AA) and kaurenoic acid (KA), were used as test analytes. Stock solutions were applied directly onto the surface, followed
by the addition of silver colloid and measurements were taken by SERS. The strongest signal (excitation at 514.5 nm) was obtained
for GA using a Raman treated thin layer where the enhancement factor value was determined to be 102. Several fundamental Raman bands for GA were found at 1622, 1593, 1570, 1542, 1366 and 1236 cm−1. When the monolithic silica layer was used, no useful SERS signals were observed. The SERS spectra on modified aluminium
backplate for AA and GA were quite similar and no SERS spectrum was obtained for KA. Future research will be concerned towards
the use of nanostructured surfaces for SERS analysis.
An erratum to this article can be found at 相似文献
387.
Werner Uhl Christian Appelt Jana Backs Hans Klöcker Andrej Vinogradov Hauke Westenberg 《无机化学与普通化学杂志》2014,640(1):106-109
The synthesis of dineopentylaluminum hydride, H‐Al(CH2CMe3)2, is known in the literature since 1988. We determined the crystal structure of this important starting material and found different ring sizes with dimeric versus trimeric formula units. The molecular shape depends on the polarity of the solvent used for recrystallization (n‐pentane or 1,2‐difluorobenzene). The synthesis of diphenylaluminum hydride, which is also long known in the literature, was optimized. It has a trimeric structure in the solid state with an Al3H3 heterocycle. 相似文献
388.
Andrej Staško Viktor Milata Zuzana Barbieriková Vlasta Brezová 《Magnetic resonance in chemistry : MRC》2014,52(1-2):22-26
4‐Oxoquinoline derivatives (quinolones) represent heterocyclic compounds with a variety of biological activities, along with interesting chemical reactivity. The quinolone derivatives possessing secondary amino hydrogen at the nitrogen of the enaminone system are oxidized with 3‐chloroperbenzoic acid to nitroxide radicals in the primary step while maintaining their 4‐pyridone ring. Otherwise, N‐methyl substituted quinolones also form nitroxide radicals coupled with the opening of the 4‐pyridone ring in a gradual oxidation of the methyl group via the nitrone–nitroxide spin‐adduct cycle. This was confirmed in an analogous oxidation using N,N‐dimethylaniline as a model compound. N‐Ethyl quinolones in contrast to its N‐methyl analog form only one nitroxide radical without a further degradation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
389.
Edelson-Averbukh M Shevchenko A Pipkorn R Lehmann WD 《Journal of the American Society for Mass Spectrometry》2011,22(12):2256-2268
Unambiguous differentiation between isobaric sulfated and phosphorylated tyrosine residues (sTyr and pTyr) of proteins by mass spectrometry is challenging, even using high resolution mass spectrometers. Here we show that upon negative ion mode collision-induced dissociation (CID), pTyr- and sTyr-containing peptides exhibit entirely different modification-specific fragmentation patterns leading to a rapid discrimination between the isobaric covalent modifications using the tandem mass spectral data. This study reveals that the ratio between the relative abundances of [M-H-80](-) and [M-H-98](-) fragment ions in ion-trap CID and higher energy collision dissociation (HCD) spectra of singly deprotonated +80 Da Tyr-peptides can be used as a reliable indication of the Tyr modification group nature. For multiply deprotonated +80 Da Tyr-peptides, CID spectra of sTyr- and pTyr-containing sequences can be readily distinguished based on the presence/absence of the [M-nH-79]((n-1)-) and [M-nH-79-NL]((n-1)-) (n=2, 3) fragment ions (NL=neutral loss). 相似文献
390.
In situ photoexcitation of silver-doped titania nanopowders for activity against bacteria and yeasts
Kowal K Wysocka-Król K Kopaczyńska M Dworniczek E Franiczek R Wawrzyńska M Vargová M Zahoran M Rakovský E Kuš P Plesch G Plecenik A Laffir F Tofail SA Podbielska H 《Journal of colloid and interface science》2011,362(1):50-57
Photocatalytic and in situ microbial activity of the amorphous and annealed states of Ag-doped and un-doped titania were examined. Studies on their structure, morphology, composition, and the photo-absorption characteristics of these materials were performed. These results were correlated with the photocatalytic and microbial activity against methicillin resistant Staphylococcus aureus K324 (MRSA), methicillin susceptible S. aureus ATCC 25923 (MSSA), Escherichia coli PA 170, and yeasts Candida albicans ATCC 90028. The annealed powders containing anatase form of titania exhibited relatively higher photocatalytic activity,corresponding to activity against MRSA,when exposed to UV-A radiation. In comparison, amorphous powders exhibited low photoactivity and showed poor antibacterial performance against MRSA under UV-A exposure. Doping of amorphous titania with Ag resulted in an anti-MRSA effect without exposure to UV radiation. In the Ag-doped crystalline anatase samples, the size of Ag primary nanocrystallites increased, which led to the decrease in the surface concentration of Ag and detriment anti-MRSA activity. 相似文献