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61.
62.
Characterization of a new norfloxacin metabolite monitored during a bioequivalence study by means of mass spectrometry and quantum computation 总被引:1,自引:0,他引:1
Medvedovici A Sora DI Ionescu S Hillebrand M David V 《Biomedical chromatography : BMC》2008,22(10):1100-1107
A bioequivalence study of two formulations containing norfloxacin was used for identification and assay of the metabolite of norfloxacin in human serum samples. The bioequivalence study was based on an analytical method using liquid chromatography with fluorescence detection. The plasmatic profile of metabolite was similar to norfloxacin for both formulations. Three plasma fractions of norfloxacin metabolite from a volunteer were isolated by liquid chromatography and investigated by atmospheric-pressure chemical ionization mass-spectrometry. The structure of norfloxacin metabolite (7-aminoethylenamino-6-fluoro-4-hydroxy quinoline-3-carboxylic acid) was identified taking into account also the mass spectrometry investigations achieved for norfloxacin and ciprofloxacin (used as internal standard for the analytical method). A theoretical procedure based on quantum chemical calculations has been also used to explain the mass fragmentation in molecules of norfloxacin metabolite that differ from the molecule of norfloxacin. 相似文献
63.
Andreea Irina Barzic Dumitru Popovici Camelia Hulubei Iuliana Stoica Magdalena Aflori Simona Dunca 《International Journal of Polymer Analysis and Characterization》2016,21(1):77-84
This article has been retracted. 相似文献
64.
Asymmetric Brønsted Acid Catalyzed Substitution of Diaryl Methanols with Thiols and Alcohols for the Synthesis of Chiral Thioethers and Ethers
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Adisak Chatupheeraphat Hsuan‐Hung Liao Steffen Mader Makoto Sako Prof. Dr. Hiroaki Sasai Dr. Iuliana Atodiresei Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2016,55(15):4803-4807
An enantioselective addition of thiols and alcohols to aza‐ortho‐quinone methides, starting from diaryl methanols, was developed. The asymmetric additions occur under mild reaction conditions in the presence of chiral phosphoric acids and furnish the corresponding adducts with excellent yields and enantioselectivities. 相似文献
65.
Electrophoretic methods for analysis of urinary polypeptides in IgA-associated renal diseases 总被引:2,自引:0,他引:2
Julian BA Wittke S Novak J Good DM Coon JJ Kellmann M Zürbig P Schiffer E Haubitz M Moldoveanu Z Calcatera SM Wyatt RJ Sýkora J Sládková E Hes O Mischak H McGuire BM 《Electrophoresis》2007,28(23):4469-4483
We evaluated the utility of SDS-PAGE/Western blot and CE coupled with MS (CE-MS) for detection of urinary polypeptide biomarkers of renal disease in patients with IgA-associated glomerulonephritides. In a reference cohort of 402 patients with various renal disorders and 207 healthy controls, we defined CE-MS patterns of renal damage and IgA nephropathy (IgAN). In a blinded analysis of a separate cohort of patients with IgAN (n = 10), Henoch-Schoenlein purpura (HSP) with nephritis (n = 10), and IgA-associated glomerulonephritis due to hepatitis C virus (HCV)-induced cirrhosis (n = 9), and healthy controls (n = 12), we compared SDS-PAGE/Western blot and CE-MS against clinical urinalysis for detection of urinary proteins/polypeptides. Urinalysis indicated proteinuria for 50, 90, and 33% of patients, respectively, and for none of the healthy controls. SDS-PAGE/Western blot showed urinary polypeptides abnormality for 90, 80, and 67% of patients, respectively, and for none of the healthy controls. CE-MS indicated a Renal Damage Pattern in 80, 80, and 100 of patients, respectively, and in 17% of healthy controls, with the more specific IgAN Pattern in 90, 90, and 1%, respectively, and in none of the healthy controls. Based on differences in CE-MS patterns, the disease mechanisms may differ among various IgA-associated glomerulonephritides. These exploratory findings should be evaluated in a prospective study with contemporaneous renal biopsy and urinary testing. If validated, it may be feasible to adapt the CE-MS methodology to develop novel tests to detect renal injury at earlier stages, assess clinical manifestations, and monitor responses to therapy in patients with IgA-associated renal diseases. 相似文献
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67.
The experimentally known dependence in RP-HPLC of the retention factor k′ on octanol/water partition coefficient (K ow) has been examined based on solvophobic theory. The result showed that the dependence provides a means for the evaluation of phase ratio (Φ) of RP-HPLC columns, and of the equilibrium constant for a given compound and mobile phase. Using this theory, the phase ratio was evaluated for a set of seven different C18 columns (five having fully porous particles and two core–shell particles), and the equilibrium constants were calculated for four homologous series of compounds in two mobile phase systems. One mobile phase was methanol/aqueous solution of 0.1% H3PO4, and the other was acetonitrile/aqueous solution of 0.1% H3PO4. Besides providing the values for Φ for the evaluated columns, the results of the study indicated that for a specific composition of the mobile phase and for a given compound displaying only hydrophobic interactions, the equilibrium constant K(X) for different C-18 columns is basically the same. The data were further used to provide guidance in the selection of a chromatographic column for a specific separation based on K ow values and chemical structure of the analytes. The study indicated that the separation of compounds with identical polar groups (or no polar groups) and with very close values for the K ow cannot be achieved based only on hydrophobic interactions that dominate the separation on RP-type columns. Only column that displays polar interactions may provide a solution to such separations. For hydrocarbons with close K ow values, the separation cannot be achieved even on columns with some polarity. On the other hand, even compounds with equal K ow values, but with different functionalities can be separated on RP-HPLC columns without involving polar interactions. The compounds with different K ow values are expected to be easily separated on RP-HPLC columns. 相似文献
68.
Morjan Iuliana P. Alexandrescu Rodica Morjan Ion Luculescu Catalin Vasile Eugeniu Osiceanu Petre Scarisoreanu Monica Demian Gabriela 《Journal of nanoparticle research》2013,15(11):1-11
Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug. 相似文献
69.
70.
Irina-Claudia Grig-Alexa Iuliana Simionescu Oana-Irina Patriciu Stéphane Massip Adriana-Luminita Fînaru Christian Jarry Jean-Michel Léger Gérald Guillaumet 《Tetrahedron letters》2012,53(15):1885-1888
The formation of alkoxy substituted di(pyridin-2-yl)amines and N-arylpyridin-2-ylamines by nitro group reduction is described. Unexpected substitution of ortho with the amino at C-6 was observed during the reduction using SnCl2·2H2O in different alcohols. The influence of the nature of the atom at the 3- and 5-positions of nitro-substituted di(pyridin-2-yl)amines and N-arylpyridin-2-ylamines was investigated. 相似文献