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81.
Valentina Uivarosi Mihaela Badea Rodica Olar Dana Marinescu Teodor Octavian Nicolescu George Mihai Nitulescu 《Journal of Thermal Analysis and Calorimetry》2011,105(2):645-650
Three new complexes with ligands belong to the fluoroquinolone class having the general formula [RuL2Cl2]Cl nH2O ((1) L: norfloxacin (nf), n = 4; (2) L: ciprofloxacin (cp), n = 3; (3) L: enrofloxacin (enro), n = 5) were synthesized and characterized by chemical analysis UV–Vis and IR spectroscopy. In all complexes fluoroquinolone
derivative acts as bidentate chelate ligand. The thermal behavior steps were investigated in synthetic air flow. The thermal
transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative degradation,
as well as RuCl3 conversion in RuO2. 相似文献
82.
83.
Natalya V. Kul''kova Valentina G. Kotova Marina Yu. Kvyatkovskaya Dmitry Yu. Murzin 《Reaction Kinetics and Catalysis Letters》2000,69(1):95-104
Influence of metal ions on hydrogen peroxide decomposition on the liquid-phase ammoximation of cyclohexanone was studied in homogeneous and heterogeneous (over titanium silicalite) conditions. The latter reaction is accompanied by side reactions, which deactivate the catalyst. Deactivation behavior is discussed. 相似文献
84.
Alessandro Sorrenti Marco Diociaiuti Valentina Corvaglia Pietro Chistolini Giovanna Mancini 《Tetrahedron: Asymmetry》2009,20(23):2737-2741
The recognition of the enantiomeric couples of ditryptophan in Langmuir films of N-hexadecanoyl-l-proline was investigated by surface pressure–area (π–A) isotherm measurements and Brewster angle microscopy experiments. The π–A isotherms relative to the films including the enantiomeric dipeptides show small differences whereas an evident enantiodiscrimination is observed by Brewster angle microscopy images. 相似文献
85.
Federica Rossella Elisa Polledri Valentina Bollati Andrea Baccarelli Silvia Fustinoni 《Rapid communications in mass spectrometry : RCM》2009,23(17):2637-2646
A method for the determination of DNA global methylation, taken as the ratio (%) of 5‐methylcytosine (5mCyt) versus the sum of cytosine (Cyt) and 5mCyt, via gas chromatography/mass spectrometry (GC/MS), was developed and validated. DNA (2.5 µg) was hydrolyzed with aqueous formic acid 88%, spiked with cytosine‐2,4‐13C2,15N3 and 5‐methyl‐2H3‐cytosine‐6‐2H1 as internal standards, and derivatized with N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroacetamide and 1% tert‐butyldimethylchlorosilane, in the presence of acetonitrile and pyridine. GC/MS, operating in single ion monitoring mode, separated and specifically detected all nucleobases as tert‐butyldimethylsilyl derivatives, without interferences, with the exception of guanosine. The method was linear throughout the range of clinical interest and had good sensitivity, with a limit of quantification of 3.2 pmol for Cyt and 0.056 pmol for 5mCyt, the latter corresponding to a methylation level of 0.41%. Intra‐ and inter‐day precision and accuracy were below 4.0% for both analytes and methylation. The matrix absolute effect, process efficiency and coefficient of variation ranged from 96.5 to 101.2%. The matrix relative effect was below 1%. The method was applied to the analysis of different human DNAs, including: nonmethylated DNA from PCR (methylation 0.00%), hypermethylated DNA prepared using M.SssI CpG methyltransferase (methylation 18.05%), DNA from peripheral blood leukocytes of healthy subjects (N = 6, median methylation 5.45%), DNA from bone marrow of leukemia patients (N = 5, 3.58%) and DNA from myeloma cell lines (N = 4, 2.74%). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
86.
The large unit cells, the enormous flexibility and variation in structural motifs of MOFs represent a big challenge in the characterization of MOF materials, particularly in cases where single crystal diffraction data are not available. In this critical review it is shown that in cases where only powder diffraction data are available additional structural information, particularly regarding local coordination within the inorganic cluster, are often mandatory in order to solve the structure. There are also cases where the inorganic cluster does not follow the symmetry of the overall structure. In such cases diffraction techniques will just "see" an average structure, missing the local structure: a lack that may be critical for understanding the specific properties of the material. In both cases, EXAFS spectroscopy is the tool that provides complementary structural information on the inorganic cluster and the way it binds to the ligand. Selected examples will show how EXAFS will be relevant in: (i) confirming the structure obtained from diffraction refinements; (ii) highlighting that the inorganic cornerstone has a lower symmetry with respect to that of the organic framework; (iii) obtaining the local structure of the inorganic cluster in the desolvated material when desolvation causes a partial loss of long range order; (iv) obtaining the local structure of the inorganic cluster in the desolvated material after coordination of a probe (or reactant) molecule, including cluster deformation upon molecule coordination and metal-molecule binding distance; (v) evidencing the presence of impurities in the form of amorphous extra-phases (339 references). 相似文献
87.
Diastereomers of 3-amino-2-hydroxy-6-methylheptanoic acid (AHMHA), a new amino acid unit in perthamides C and D, have been synthesized from commercially available 4-methylpentanol in a concise manner and 50% average overall yield. Comparison of the 1H and 13C NMR data, optical rotation data and Marfey’s analysis of the resulting isomers with the natural fragment unambiguously allowed the configurational assignment of the natural residue as (2R,3R). A structural revision of perthamides C and D is also reported. 相似文献
88.
Irene Benedetti Valeri Obukhovskii Valentina Taddei 《NoDEA : Nonlinear Differential Equations and Applications》2014,21(6):795-812
In this paper we study the controllability for a class of semilinear differential inclusions in Banach spaces. Since we assume the regularity of the nonlinear part with respect to the weak topology, we do not require the compactness of the evolution operator generated by the linear part. As well we are not posing any conditions on the multivalued nonlinearity expressed in terms of measures of noncompactness. We are considering the usual assumption on the controllability of the associated linear problem. Notice that, in infinite dimensional spaces, the above mentioned compactness of the evolution operator and linear controllability condition are in contradiction with each other. We suppose that the nonlinear term has convex, closed, bounded values and a weakly sequentially closed graph when restricted to its second argument. This regularity setting allows us to solve controllability problem under various growth conditions. As application, a controllability result for hyperbolic integro-differential equations and inclusions is obtained. In particular, we consider controllability of a system arising in a model of nonlocal spatial population dispersal and a system governed by the second order one-dimensional telegraph equation. 相似文献
89.
Alexander A. Simenel Galina A. Dokuchaeva Lubov' V. Snegur Alexey N. Rodionov Mikhail M. Ilyin Svetlana I. Zykova Larissa A. Ostrovskaya Natalia V. Bluchterova Margarita M. Fomina Valentina A. Rikova 《应用有机金属化学》2011,25(1):70-75
Ferrocenylalkyl thiopyrimidines ( 6a–d to 9a–d ) were prepared via the reaction of the α‐(hydroxy)alkyl ferrocenes, FcCHR(OH) ( 1a–d ; Fc = ferrocenyl; R = H, Me, Et, Ph), with 2‐thiopyrimidines ( 2 – 5 ) in acetone at room temperature in the presence of TFA, yielding 50–95%. The resulting enantiomers were resolved using HPLC on modified cellulose as chiral selector. The antitumor activities of S‐ferrocenylethyl 2‐thiopyrimidine ( 6b ) against two murine solid tumor models, carcinoma 755 (Ca755) and Lewis lung carcinoma (LLC) were evaluated in vivo. The strong antitumor effect of compound 6b on Ca755 and LLC was demonstrated. The index of tumor growth inhibition on Ca755 equaled 95% in comparison with control. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
90.