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71.
Pedro A. Fernandes Elsa S. Henriques Vineet Pande Maria. J. Ramos Ana R. R. Maia André A. S. Almeida Bruno F. B. Silva Carla M. S. Ribeiro César F. B. Ribeiro David S. M. Ribeiro Diana A. P. Fonseca Eva M. S. Cunha Filipe R. N. C. Maia Joana A. A. Pereira João P. G. Pacheco Joaquim A. A. D. Ferreira Liliana R. C. Matos Manuel A. B. P. Pinto Maria C. S. Borges Paulo J. C. R. Magalhães Pedro F. R. D. Teixeira Pedro N. B. C. Veloso Ricarte J. F. Ferreira Sandro S. Gomes Tiago F. Barros Tiago S. J. T. Selão Virgínia M. M. C. Fernandes 《Theoretical chemistry accounts》2005,113(4):197-204
We present a series of new inhibitors of the association between nuclear factor kappa B (NF-B) and the corresponding B site in DNA. They were designed using the lead compound 15-deoxy-12,14 -prostaglandin J2 (PGJ2), which is a natural product with demonstrated inhibitory efficiency for this system. First, the binding mode of PGJ2 to NF-B was unraveled by GOLD docking calculation. Subsequently, substitutions were made to PGJ2 to optimize its association with NF-B. Care was taken not to strongly increase the reactivity of the new compounds, and to keep the overall shape, size and hydrophilicity of the lead compound, which should render them a similar bioavailability. Molecular mechanics calculations were performed to decide on the suitability of the substitutions, and to evaluate the energies of association with NF-B. Density functional theory calculations were performed also to study the overall reactivity of the substituted drugs towards NF-B. Important general conclusions were obtained, concerning the improvement of these natural inhibitors; namely, a set of rational methodologies were deduced to improve the association between the PGJ2 derivatives and NF-B, and their efficiency demonstrated by generating a set of substituted complexes, some of them with a very much increased affinity for NF-B, opening new doors to enlarge the therapeutic capabilities of this class of drugs. 相似文献
72.
73.
Klaus Müllen Siglinde Bender Eleni Kotzamani Hans Schmickler Bruno Frei Hans R. Wolf 《Tetrahedron letters》1981,22(36):3513-3516
The conformational mobility of a series of conjugated dienones is investigated by low-temperature NMR- and IR-spectroscopy and interpreted in terms of substituent effects. 相似文献
74.
Giuseppe Bruno Santo Lanza Francesco Nicol Giuseppe Tresoldi Giuseppe Rosace 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):m316-m318
The title compound, [PdPtCl(C3H5)(C6H10N2S2)(C17H14NP)]·CHCl3, was obtained by deprotonation of the initial platinum(II) complex of the dithioxamide and subsequent reaction with [Pd(η3‐C3H5)(μ‐Cl)]2. Both metal atoms exhibit a square‐planar coordination geometry, with the two planes forming a dihedral angle of 21.7 (2)°. The dithioxamide bis‐chelating bridge is flat. 相似文献
75.
Petra Spitzer Bruno Rossi Yves Gaignet Stéphane Mabic Uwe Sudmeier 《Accreditation and quality assurance》2005,10(3):78-81
There is currently a major issue with the calibration of conductivity meters used for high purity water: the lack of availability of a reference material or reference methods for low conductivity ranges (conductivity below 1 S cm–1 at 25.0 °C, resistivity >1 M cm at 25.0 °C). This paper describes the current status of conductivity measurements in high purity water. A new and improved approach, currently being investigated, should allow us to make the calibration of conductivity meters used for low conductivity ranges traceable to the SI.Milipore, Milli-Q and Elix are registered trademarks of Millipore Corporation. 相似文献
76.
On the mechanism of nanopore filling of SAPO-5 molecular sieve by nitrogen molecules 总被引:1,自引:0,他引:1
Boddenberg B Radha Rani V Grosse R 《Langmuir : the ACS journal of surfaces and colloids》2004,20(25):10962-10969
SAPO-5 molecular sieve was synthesized according to patent literature and characterized with X-ray diffraction, electron microscopy (SEM, TEM), and solid state magic angle spinning NMR spectroscopy. The material of particles in the micrometer region was found to consist of ca. 20 nm microcrystallites packed in mostly parallel orientation to ca. 200 nm sized agglomerates. The nitrogen adsorption isotherm was measured at 77.6 K over ca. 7 decades of pressure up to pore saturation. The course of the isotherm is interpreted to consist of filling of the nanopores (diameter, 0.73 nm) up to 2N(2)/unit cell, subsequent multilayer adsorption on the outer surface of the agglomerates, and, finally, pore condensation in the interparticle adsorption space. The nanopore adsorption can be quantitatively reproduced with the statistical mechanical model of a quasi one-dimensional lattice gas taking intermolecular interactions into account. The evaluated energy parameters are of physically reasonable magnitude and agree with literature data. The multilayer part of the adsorption isotherm can be well represented by the Brunauer-Emmett-Teller model yielding a specific outer space area (63 m(2) g(-)(1)) which is consistent with estimated geometrical and pore size analysis data. 相似文献
77.
The new monoterpenoid 5-isobutyl-3-methyl-2-furancarbaldehyde was isolated from Tagetes glandulifera Schrank and its structure confirmed by synthesis. 相似文献
78.
Laura M. Bruno José L. de Lima Filho Eduardo H. de M. Melo Heizir F. de Castro 《Applied biochemistry and biotechnology》2004,113(1-3):189-199
Mucor miehei lipase was immobilized on magnetic polysiloxane-polyvinyl alcohol particles by covalent binding with high activity recovered.
The performance of the resulting immobilized biocatalyst was evaluated in the synthesis of flavor esters using heptane as
solvent. The impact on reaction rate was determined for enzyme concentration, molar ratio of the reactants, carbon chain length
of the reactants, and alcohol structure. Ester synthesis was maximized for substrates containing excess acyl donor and lipase
loading of 25 mg/mL. The biocatalyst selectivity for the carbon chain length was found to be different concerning the organic
acids and alcohols. High reaction rates were achieved for organic acids with 8 or 10 carbons, whereas increasing the alcohol
carbon chain length from 4 to 8 carbons gave much lower esterification yields. Optimal reaction rate was determined for the
synthesis of butyl caprylate (12 carbons). Esterification performance was also dependent on the alcohol structure, with maximum
activity occurring for primary alcohol. Secondary and tertiary alcohols decreased the reaction rates by more than 40%. 相似文献
79.
Bujoli B Lane SM Nonglaton G Pipelier M Léger J Talham DR Tellier C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(7):1980-1988
A new process for preparing oligonucleotide arrays is described that uses surface grafting chemistry which is fundamentally different from the electrostatic adsorption and organic covalent binding methods normally employed. Solid supports are modified with a mixed organic/inorganic zirconium phosphonate monolayer film providing a stable, well-defined interface. Oligonucleotide probes terminated with phosphate are spotted directly on to the zirconated surface forming a covalent linkage. Specific binding of terminal phosphate groups with minimal binding of the internal phosphate diesters has been demonstrated. The mixed organic/inorganic thin films have also been extended for use arraying DNA duplex probes, and therefore represent a viable general approach to DNA-based bioarrays. Ideas for interfacing mixed organic/inorganic interfaces to other bioapplications are also discussed. 相似文献
80.
Ehresmann JO Wang W Herreros B Luigi DP Venkatraman TN Song W Nicholas JB Haw JF 《Journal of the American Chemical Society》2002,124(36):10868-10874
Assessing the degree of proton transfer from a Br?nsted acid site to one or more adsorbed bases is central to arguments regarding the strength of zeolites and other solid acids. In this regard certain solid-state NMR measurements have been fruitful; for example, some (13)C, (15)N, or (31)P resonances of adsorbed bases are sensitive to protonation, and the (1)H chemical shift of the Br?nsted site itself reflects hydrogen bonding. We modeled theoretically the structures of adsorption complexes of several bases on zeolite HZSM-5, calculated the quadrupole coupling constants (Q(cc)) and asymmetry parameters (eta) for aluminum in these complexes and then in turn simulated the central transitions of their (27)Al MAS NMR spectra. The theoretical line width decreased monotonically with the degree of proton transfer, reflecting structural relaxation around aluminum as the proton was transferred to a base. We verified this experimentally for a series of adsorbed bases by way of single-pulse MAS and triple quantum MQMAS (27)Al NMR. The combined theoretical and experimental approach described here provides a strategy by which (27)Al data can be applied to resolve disputed interpretations of proton transfer based on other evidence. 相似文献