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排序方式: 共有136条查询结果,搜索用时 31 毫秒
91.
92.
Daniel Crístian Ferreira Soares André Luís Branco de Barros Raquel Gouvêa dos Santos Edésia Martins Barros de Sousa Gilson Andrade Ramaldes 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):63-66
In this work the apoptosis mediated by caspase-3 and p53-dependent anticancer effects of 159Gd-DTPA-BMA metal complex were evaluated against RT2 glioblastoma cells. The results showed that the mechanism of cell death involves apoptosis by caspase-3 activation. Furthermore, the involvement of p53 protein triggered by 159Gd-DTPA-BMA in these cells was verified preliminarily. Considering these finding, the radioactive complex can be considered as potential therapeutic alternative agent against cancer. 相似文献
93.
Santos AM Vasconcelos T Mateus E Farrall MH Gomes da Silva MD Paiva MR Branco M 《Journal of chromatography. A》2006,1105(1-2):191-198
Pine forests constitute some of the most important renewable resources supplying timber, paper and chemical industries, among other functions. Characterization of the volatiles emitted by different Pinus species has proven to be an important tool to decode the process of host tree selection by herbivore insects, some of which cause serious economic damage to pines. Variations in the relative composition of the bouquet of semiochemicals are responsible for the outcome of different biological processes, such as mate finding, egg-laying site recognition and host selection. The volatiles present in phloem samples of four pine species, P. halepensis, P. sylvestris, P. pinaster and P. pinea, were identified and characterized with the aim of finding possible host-plant attractants for native pests, such as the bark beetle Tomicus piniperda. The volatile compounds emitted by phloem samples of pines were extracted by headspace solid-phase micro extraction, using a 2cm 50/30mm divinylbenzene/carboxen/polydimethylsiloxane table flex solid-phase microextraction fiber and its contents analyzed by high-resolution gas chromatography, using flame ionization and a non polar and chiral column phases. The components of the volatile fraction emitted by the phloem samples were identified by mass spectrometry using time-of-flight and quadrupole mass analyzers. The estimated relative composition was used to perform a discriminant analysis among pine species, by means of cluster and principal component analysis. It can be concluded that it is possible to discriminate pine species based on the monoterpenes emissions of phloem samples. 相似文献
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95.
Discriminant analysis plays an important role in multivariate statistics as a prediction and classification method. It has been successfully applied in many fields of work and research. As it happens with other multivariate methods, discriminant analysis is highly vulnerable to the presence of outliers that commonly occur in many real world data sets. The lack of robustness of the classical estimators on which the linear discriminant function is based is a severe disadvantage and several authors have worked to find efficient ways to prevent the damage that outliers can cause. This paper focuses on the projection-pursuit approach to discriminant analysis. The projection-pursuit estimators are described and theoretical properties are deduced and their relevance is highlighted. These include Fisher consistency, affine equivariance, partial influence functions and asymptotic distributions. Application to real data and a simulation study reveal the robustness of the projection-pursuit approach. In both analyses the data relates to a large number of variables, a situation that is becoming common when new technology is applied to data gathering. 相似文献
96.
The use of the solvent systems water/ionic liquid or water/ionic liquid/tert-butanol provides a recoverable, reusable, robust and simple system for the asymmetric dihydroxylation of olefins, based on the immobilization of the osmium-ligand catalyst in the ionic liquid phase. 相似文献
97.
98.
We show that, in the framework of three light neutrino species with hierarchical masses and assuming no fine tuning between the entries of the neutrino mass matrix, one can use the solar neutrino data to obtain information on the element U(e3) of the lepton mixing matrix. Conversely, a measurement of U(e3) in atmospheric or long baseline accelerator or reactor neutrino experiments would help discriminate between possible oscillation solutions of the solar neutrino problem. 相似文献
99.
The implications of a Z4 horizontal symmetry model of flavor mixing for CP violation are studied in the framework of minimal SU(2)L × SU(2)R × U(1)B – L gauge theory. We show that CP violation in this model arises purely from right-handed currents. We also note that spontaneous breaking of CP symmetry requires a fine tuning of coupling parameters to the level of , which can be avoided by the inclusion of one additional singlet Higgs field, of the kind recently introduced for other purposes. 相似文献
100.
Constraints on light axions are derived using data from nuclear decays and stability of red giant stars. Special emphasis is given to the implications on the model proposed by Dine, Fischler and Srednicki. 相似文献