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991.
Curis E Dubar F Nicolis I Bénazeth S Biot C 《The journal of physical chemistry. A》2012,116(23):5577-5585
Antimalarial compounds ruthenoquine and methylruthenoquine were studied by X-ray absorption spectroscopy both in solid state and in solution, in normal (aqueous or CH(2)Cl(2) solutions) and oxidative (aqueous solution with H(2)O(2), either equimolar or in large excess) conditions, to detect small changes in the coordination sphere of the ruthenium atom. Since changes in the EXAFS spectra of these compounds are quite subtle, a complete procedure was developed to assess the different sources of uncertainties in fitted structural parameters, including the use of multivariate statistic methods for simultaneous comparison of edge energy correction ΔE(0) and distances, which can take into account the very strong correlation between these two parameters. Factors limiting the precision of distance determination depend on the recording mode. In transmission mode, the main source of uncertainty is the data reduction process, whereas in fluorescence mode, experimental noise is the main source of variability in the fitted parameters. However, it was shown that the effects of data reduction are systematic and almost identical for all compounds; hence, they can be ignored when comparing distances. Consequently, for both fluorescence and transmission recorded spectra, experimental noise is the limiting factor for distance comparisons, which leads to the use of statistical methods for comparing distances. Univariate methods, focusing on the distance only, are shown to be less powerful in detecting changes in distances than bivariate methods making a simultaneous comparison of ΔE(0) and distances. This bivariate comparison can be done either by using the Hotelling's T(2) test or by using a graphical comparison of Monte Carlo simulation results. We have shown that using these methods allows for the detection of very subtle changes in distances. When applied to ruthenoquine compounds, it suggests that the implication of the nonbinding doublet of the aminoquine nitrogen in either protonation or methylation enhances the tilt of the two cyclopentadienyls. It also suggests that ruthenoquine and methylruthenoquine are, at least partially, oxidized in the presence of H(2)O(2), with a small decrease in the Ru-C bond length and increase in the edge energy. 相似文献
992.
VB Arion A Dobrov S Göschl MA Jakupec BK Keppler P Rapta 《Chemical communications (Cambridge, England)》2012,48(68):8559-8561
A modified paullone ligand bearing a TEMPO free-radical unit (HL) and its ruthenium(ii) and osmium(ii)-arene complexes [M(p-cymene)(HL)Cl]Cl·nH(2)O (M = Ru, Os) exhibit high antiproliferative activity in human cancer cell lines. 相似文献
993.
A permutominide is a set of cells in the plane satisfying special connectivity constraints and uniquely defined by a pair of permutations.
It naturally generalizes the concept of permutomino, recently investigated by several authors and from different points of view [1, 2, 4, 6, 7]. In this paper, using bijective
methods, we determine the enumeration of various classes of convex permutominides, including, parallelogram, directed convex,
convex, and row convex permutominides. As a corollary we have a bijective proof for the number of convex permutominoes, which
was still an open problem. 相似文献
994.
Simone Cerreia-Vioglio Fabio Maccheroni Massimo Marinacci Luigi Montrucchio 《Journal of Mathematical Analysis and Applications》2012,385(2):895-912
We establish integral representation results for suitably pointwise continuous and comonotonic additive functionals of bounded variation defined on Stone lattices. As an application, we prove a comonotonic version of the Daniell–Stone Theorem. 相似文献
995.
996.
Simone Draxler 《Optics Communications》2010,283(6):1050-180
A novel detection scheme for pump-repump-probe spectroscopy is presented, where the use of modulation and referencing allows to record the efficiency of a photochemical reaction as a function of the pump-repump delay in a single measurement. This new technique is applied to investigate the ring-opening reaction of an indolylfulgide after pre-excitation. Here the reaction efficiency doubles, when the excitation pulse is very close to the pre-excitation pulse, and the improvement of the efficiency decays with increasing pump-repump delay on the time scale of about 5 ps. 相似文献
997.
Marcelo Fernando Kern Simone de Faria Maraschin Débora Vom Endt Augusto Schrank Marilene Henning Vainstein Giancarlo Pasquali 《Applied biochemistry and biotechnology》2010,160(7):1933-1946
The chit1 gene from the entomopathogenic fungus Metarhizium anisopliae, encoding the endochitinase CHIT42, was placed under the control of the CaMV 35S promoter, and the resulting construct was
transferred to tobacco. Seventeen kanamycin-resistant transgenic lines were recovered, and the presence of the transgene was
confirmed by polymerase chain reactions and Southern blot hybridization. The number of chit1 copies was determined to be varying from one to four. Copy number had observable effects neither on plant growth nor development.
Substantial heterogeneity concerning production of the recombinant chitinase, and both general and specific chitinolytic activities
were detected in leaf extracts from primary transformants. The highest chitinase activities were found in plants harboring
two copies of chit1 inserts at different loci. Progeny derived from self-pollination of the primary transgenics revealed a stable inheritance
pattern, with transgene segregation following a mendelian dihybrid ratio. Two selected plants expressing high levels of CHIT42
were consistently resistant to the soilborne pathogen Rhizoctonia solani, suggesting a direct relationship between enzyme activity and reduction of foliar area affected by fungal lesions. To date,
this is the first report of resistance to fungal attack in plants mediated by a recombinant chitinase from an entomopathogenic
and acaricide fungus. 相似文献
998.
We computationally examine various aspects of the reaction dynamics of the photodissociation and recombination of molecular iodine. We use our recently proposed formalism to calculate time-dependent x-ray scattering signal changes from first principles. Different aspects of the dynamics of this prototypical reaction are studied, such as coherent and noncoherent processes, features of structural relaxation that are periodic in time versus nonperiodic dissociative processes, as well as small electron density changes caused by electronic excitation, all with respect to x-ray scattering. We can demonstrate that wide-angle x-ray scattering offers a possibility to study the changes in electron densities in nonperiodic systems, which render it a suitable technique for the investigation of chemical reactions from a structural dynamics point of view. 相似文献
999.
Primik MF Göschl S Jakupec MA Roller A Keppler BK Arion VB 《Inorganic chemistry》2010,49(23):11084-11095
A number of indolo[3,2-c]quinolines were synthesized and modified at the lactam unit to provide a peripheral binding site able to accommodate metal ions. Potentially tridentate ligands HL(1a)-HL(4a) and HL(1b)-HL(4b) were reacted with copper(II) chloride in isopropanol/methanol to give novel five-coordinate copper(II) complexes [Cu(HL(1a-4a))Cl(2)] and [Cu(HL(1b-4b))Cl(2)]. In addition, a new complex [Cu(HL(5b))Cl(2)] and two previously reported compounds [Cu(HL(6a))Cl(2)] and [Cu(HL(6b))Cl(2)] with modified paullone ligands HL(5b), HL(6a), and HL(6b), which can be regarded as close analogues of indoloquinolines HL(1b), HL(4a), and HL(4b), in which the pyridine ring was formally substituted by a seven-membered azepine ring, were synthesized for comparison. The new ligands and copper(II) complexes were characterized by (1)H and (13)C NMR, IR and electronic absorption spectroscopy, ESI mass spectrometry, magnetic susceptibility measurements in solution at 298 K ([Cu(HL(1a))Cl(2)] and [Cu(HL(4b))Cl(2)]), and X-ray crystallography ([Cu(HL(3b))Cl(2)]·3DMF, [Cu(HL(4b))Cl(2)]·2.4DMF, HL(5b) and [Cu(HL(5b))Cl(2)]·0.5CH(3)OH). All complexes were tested for cytotoxicity in the human cancer cell lines CH1 (ovarian carcinoma), A549 (non-small cell lung cancer), and SW480 (colon carcinoma). The compounds are highly cytotoxic, with IC(50) values ranging from nanomolar to very low micromolar concentrations. Substitution of the seven-membered azepine ring in paullones by a pyridine ring resulted in a six- to nine-fold increase of cytotoxicity in SW480 cells. Electron-releasing or electron-withdrawing substituents in position 8 of the indoloquinoline backbone do not exert any effect on cytotoxicity of copper(II) complexes, whereas copper(II) compounds with Schiff bases obtained from 2-acetylpyridine and indoloquinoline hydrazines are 10 to 50 times more cytotoxic than those with ligands prepared from 2-formylpyridine and indoloquinoline hydrazines. 相似文献
1000.
Claudia Simone Wagner Bianca Fischer Manuela May Alexander Wittemann 《Colloid and polymer science》2010,288(5):487-498
We report on the fabrication of colloidal clusters through the combination of spherical particles. Polystyrene latex particles
bearing amino groups on their surface were used as building blocks of the clusters. Packing of these particles with diameters
of 91 and 154 nm into assemblies with defined configurations was accomplished using narrow dispersed emulsion droplets as
templates. The building blocks of the clusters adhered to the oil–water interphase due to the Pickering effect. Subsequent
evaporation of the dispersed phase forced them to pack into small clusters. Addition of the particles via the dispersed phase
led to higher yields of clusters than if the building blocks were added via the continuous phase. All clusters had well-defined
configurations. Because the dimensions of these clusters were below 400 nm, the colloidal assemblies underlay Brownian motion,
which resulted in stable suspensions. The number and yields of different species could be controlled via the concentration
of the building blocks and surfactant within the emulsions. Moreover, the nature of the dispersed phase itself had a strong
impact on the cluster formation. When cyclohexane was used as the dispersed phase, predominately, particle doublets and triplets
were obtained. The use of toluene-in-water emulsions resulted into a broader spectrum of clusters of up to 12 constituents.
Such clusters could satisfy the demand for particles with complex but defined shapes and special symmetries for the fabrication
of novel hierarchically organized materials. 相似文献