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61.
Amílcar Pacheco 《manuscripta mathematica》2005,118(3):361-381
Let be a smooth projective curve defined over a number field k, A/k() an abelian variety and (τ, B) the k()/k-trace of A. We estimate how the rank of A(k())/τB(k) varies when we take a finite geometrically abelian cover defined over k.
This work was partially supported by CNPq research grant 304424/2003-0, Pronex 41.96.0830.00 and CNPq Edital Universal 470099/2003-8.
I would like to thank Douglas Ulmer for comments on how to treat the case of arbitrary ramification, but the conductor prime
to the ramification locus, in the case of elliptic fibrations. I would also like to thank Marc Hindry for comments on the
inequality comparing the conductors of A and A'. Finally, I also thank the referee for his comments and criticisms. 相似文献
62.
Santos MA Gil M Marques S Gano L Chaves S 《Analytical and bioanalytical chemistry》2005,381(2):413-419
A study of a series of bifunctional 3-hydroxy-4-pyridinone derivatives, containing side-chains with various alkyl-aryl-amine-amides as extra-functional groups, was conducted to assess the relevance of those groups to the Al-chelating affinity, the lipo–hydrophilic balance of the compounds, and 67Ga biodistribution in mice, in view of their potential use as Al-decorporating agents; the results were compared with those for the drug Deferriprone. Their acid–base properties and Al-chelating affinity in aqueous solution were studied by potentiometric techniques. These ligands form very stable tris-chelated Al complexes and the non-chelating extra-groups are only responsible for small differences in the complex stability (pAl1.2). At physiological pH the major ligand/complex species have different charges, because of the different extent of protonation of the ligands. The introduction of the different groups induces a well-balanced stepwise-like lipo–hydrophilic character (–0.2<log Doct./water<+1.1). The effect of each ligand on the biodistribution of 67Ga in overloaded mice is rapid blood clearance for all of them, but with different biodistribution patterns, namely excretion pathways and brain uptake/clearance, thus suggesting potential different clinical use. 相似文献
63.
In this work we study decompositions of para-complex and para-holomorphic vector-bundles endowed with a connection ? over a para-complex manifold. First we obtain results on the connections induced on the subbundles, their second fundamental forms and their curvature tensors. In particular we analyze para-holomorphic decompositions. Then we introduce the notion of para-complex affine immersions and apply the above results to obtain existence and uniqueness theorems for para-complex affine immersions. This is a generalization of the results obtained by Abe and Kurosu [AK] to para-complex geometry. Further we prove that any connection with vanishing (0, 2)-curvature, with respect to the grading defined by the para-complex structure, induces a unique para-holomorphic structure. 相似文献
64.
Ana Luiza Ribeiro de Souza Tatiana Andreani Fernando M. Nunes Douglas Lopes Cassimiro Adélia Emília de Almeida Clóvis Augusto Ribeiro Victor Hugo Vitorino Sarmento Maria Palmira Daflon Gremião Amélia M. Silva Eliana B. Souto 《Journal of Thermal Analysis and Calorimetry》2012,108(1):353-360
Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans.
Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this
article, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method
selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential
(ZP) were 500 nm and −34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy
revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised
a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were
detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography,
were 99.06 ± 0.3 and 17.48 ± 0.05, respectively. Effective incorporation of PZQ into the particles was confirmed by small
angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room
temperature (25 °C) and at 4 °C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days. Results showed a relatively
long-term physical stability after storage at 4 °C, without drug expulsion. 相似文献
65.
Amélie Juhin Christian Brouder Frank de Groot 《Central European Journal of Physics》2014,12(5):323-340
A spherical tensor expansion is carried out to express the resonant inelastic scattering cross-section as a sum of products of fundamental spectra with tensors involving wavevectors and polarization vectors of incident and scattered photons. The expression presented in this paper differs from that of the influential article by Carra et al. (Phys. Rev. Lett. 74, 3700, 1995) because it does not omit interference terms between electric dipole and quadrupole contributions when coupling each photon to itself. Some specific cases of the spherical tensor expansion are discussed. For example the case of isotropic samples is considered and the cross-section is expressed as a combination of only three fundamental spectra for the situation where electric dipole or electric quadrupole transitions in the absorption process are followed by electric dipole transitions in the emission. This situation includes the case of untextured powder samples, which corresponds to the most frequent situation met experimentally. Finally, it is predicted that some circular dichroism may be observed on isotropic samples provided that the circular polarization of the scattered beam can be detected. 相似文献
66.
67.
Américo Lemos Marta Lopes 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2882-2890
Transient azovinylphosphonates, generated in situ by base induced dehydrohalogenation of the corresponding 2-bromo- and 2-chloro-acetylphosphonate- tertbutoxycarbonyl hydrazones are intercepted by electron rich alkenes and heterocycles in hetero Diels-Alder reactions, producing tetrahydopyridazine-3-phosphonates or open chain α-hydrazono phosphonates. 相似文献
68.
We report the synthesis of new prochiral imines by the reaction of nonsymmetric benzophenone derivates, bencylamines, and anilines in good yields. All the products were characterized by 1H and 13C NMR as an isomeric E/Z mixture. Also, the molecular structures for five derivatives determined by single-crystal x-ray experiments are presented. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
69.
Barrie M. Baker Amândio Pereira Baía 《The Journal of the Operational Research Society》1995,46(6):698-707
A problem put forward recently by a Regional Water Authority differs from the well-known Capacitated Warehouse Location Problem only in that there are both weeks of normal demand levels and weeks of peak demand levels. We describe how Lagrangian relaxation based branch-and-bound algorithms have been adapted for the new problem. Computational results are given, enabling a comparison of the different approaches tried. 相似文献
70.
Bourderioux A Bénéteau V Mérour JY Baldeyrou B Ballot C Lansiaux A Bailly C Le Guével R Guillouzo C Routier S 《Organic & biomolecular chemistry》2008,6(12):2108-2117
We report the synthesis and biological evaluation of new oxophenylarcyriaflavins designed as potential anticancer agents. An efficient synthesis involving palladium-catalyzed Suzuki and Stille reactions is presented, without any indolic protective group. The central ring closure of the scaffold was performed through an electrophilic reaction on the position C-2 of the indole ring. The use of indole and 5-benzyloxyindole, along with substituted phenyl rings, generated three different scaffolds, which were successively exploited to modulate the structure. The cytotoxicity of the newly designed compounds on four cancer cell lines and activities against three kinases (CDK1, CDK5 and GSK3) were evaluated. Several compounds showed a marked cytotoxicity with IC(50) values in the sub-micromolar range, and induced important cell cycle perturbations, with a G2/M arrest. Some compounds revealed DNA binding properties and were found to inhibit topoisomerase-mediated DNA relaxation of supercoiled DNA, but these properties are not mandatory for a cytotoxic action. A novel lead compound () has been identified and warrants further investigations. 相似文献