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121.
Min Liu Mike Ronk Da Ren Judy Ostovic Nina Cauchon Zhaohui Sunny Zhou Janet Cheetham 《Journal of chromatography. A》2010,1217(22):3598-3611
A hydrophilic interaction liquid chromatography (HILIC) method was used to separate a commonly used pharmaceutical starting material, 4-aminomethylpyridine (4-AMP), and its degradants. The structures of the major degradants were characterized and elucidated without prior isolation by accurate mass measurement, MS/MS analysis and on-line hydrogen/deuterium (H/D) exchange experiments. The mass spectra obtained from H/D exchange experiments are particularly useful to differentiate structural isomers, to elucidate the fragmentation pathways, and to aid in structure elucidation in the absence of MS/MS fragmentation information. The impact of deuterium oxide and temperature on HILIC separation has also been explored here. The integration of H/D exchange with HILIC has been described here for the first time and has been demonstrated to be a powerful structure elucidation tool via the study of degradants in 4-AMP. 相似文献
122.
123.
Nina Lah Gregor Rep Primo egedin Ljubo Goli
Ivan Leban 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):642-643
The structure of the title compound, Na2[Zn(C6H11O2)4], consists of two‐dimensional polymeric sheets. The Zn2+ ions are approximately tetrahedrally coordinated by O atoms from different hexanoate anions. Both Na+ ions are six‐coordinated by carboxylate O atoms. One of the hexanoate O atoms is attached to one Zn2+ ion and one Na+ ion, and the remaining O atom is attached to two Na+ ions. 相似文献
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125.
Michael Z. Zgurovsky Pavlo O. Kasyanov Nina V. Zadoianchuk 《Applied Mathematics Letters》2012,25(10):1569-1574
We consider quasilinear autonomous inclusions of hyperbolic type. The dynamics of all weak solutions defined on the positive semi-axis of time is studied. We prove the existence of trajectory and global attractors and investigate their structure. The classes of mathematical models for piezoelectric fields containing the multidimensional law are studied. The conditions of the output of each weak solution for this problem at stationary states are given. We consider as a particular case the piezoelectric model for PZT-4 piezoceramics as one of the possible applications. 相似文献
126.
Daria V. Chernysheva Victor A. Klushin Alexander F. Zubenko Lyudmila S. Pudova Oleg A. Kravchenko Victor M. Chernyshev Nina V. Smirnova 《Mendeleev Communications》2018,28(4):431-433
The Pt/C catalysts with various Pt content (5-30 wt%) synthesized via electrochemical pulse alternating current technique have been evaluated for the base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. The higher Pt content in the catalyst (30 wt%) provides the product yield up to 65% upon performing the process in concentrated (~0.1 M) aqueous solutions of the substrate. 相似文献
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128.
Ewa Katzenellenbogen Nina A. Kocharova Georgy V. Zatonsky Maria Bogulska Danuta Witkowska Aleksander S. Shashkov 《Journal of carbohydrate chemistry》2013,32(5):545-558
ABSTRACT Lipopolysaccharide (LPS) of Hafnia alvei 23 has an acid-labile O-specific polysaccharide (OPS) with a pentasaccharide-phosphate repeating unit containing D-Glc1P, D-GlcNAc, L-Fuc, 6-deoxy-D-talose (D-6dTal), 4-acetamido-4,6-dideoxy-D-glucose (D-Qui4NAc), and an O-acetyl group. A partially degraded OPS was obtained by hydrolysis of LPS with 0.25 M sodium acetate in aqueous 0.5% acetic acid. Fractionation of LPS on Sephadex G-200 in DOC buffer allowed isolation of long-chain LPS species which, together with OPS, were studied by methylation analysis, chemical degradations (O-deacetylation, dephosphorylation with 48% hydrofluoric acid, Smith degradation), and 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and H-detected 1H,13C heteronuclear single-quantum coherence (HSQC) experiments. The following structure of the repeating unit of OPS was established: 相似文献
129.
130.
Felicita Bri?ki Nina Kop?i? Ivana ?osi? Dajana Ku?i? Marija Vukovi? 《Chemical Papers》2012,66(12):1103-1110
The tobacco industry produces large quantities of solid and liquid waste. This waste poses a significant environmental problem, as some major components are harmful and toxic. The aim of this work is to isolate and identify the nicotine-degrading microorganisms in the composting of tobacco waste. The bioremediation process for the detoxification of waste was carried out in a column reactor at an airflow-rate of 0.4 L min?1 kg?1. The concentrations of nicotine and number of CFU in the samples taken from reactor were monitored over nineteen days. After nineteen days, 89.8 % of nicotine conversion was obtained. A nicotine-degrading bacterium, strain FN, was isolated from the composting mass and identified as Pseudomonas aeruginosa on the basis of morphology, 16S rDNA sequence, and the phylogenetic characteristics. To confirm that the isolated Pseudomonas aeruginosa FN is the actual nicotine degrader, batch experiments were performed using tobacco leachate. It was confirmed that the strain FN possesses a considerable capacity to degrade nicotine with simultaneous COD removal. The Monod kinetic model for single substrate was applied to obtain the substrate degradation rate and half saturation constant. 相似文献