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排序方式: 共有467条查询结果,搜索用时 15 毫秒
461.
Andreas Rizzi Rudolf Schuh Andrea Brückner Beate Cvitkovich Leopold Kremser Ulrich Jordis Johannes Frhlich Bernhard Küenburg Laszlo Czollner 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,730(2):1455-175
An analytical assay is presented for the determination of the enantiomeric composition of galanthamine and related synthetic and natural compounds. (−)-Galanthamine is isolated from Galanthus nivalis and is used in this optical pure form in the therapy of Alzheimer’s disease. Recent efforts for a total synthesis of unichiral (−)-galanthamine is connected with the need for a fast and reliable assay for the determination of the optical purity of the end product, as well as for optimizing and controlling the final steps in total synthesis particularly the asymmetric transformation of narwedine. In this paper the enantiomeric resolution of these compounds is reported employing a capillary electrophoretic system with β-cyclodextrin derived chiral selectors. With the proposed system a number of galanthamine and narwedine derived analogous compounds could be separated, including 1-bromo- and N-alkyl-substituted compounds. 相似文献
462.
463.
Carolina Rizzi Starr Rodrigo Studart Corrêa Tarcíso de Sousa Filgueiras John Du Vall Hay Perseu Fernando dos Santos 《Landscape and Ecological Engineering》2013,9(1):189-201
Tree establishment on degraded sites has failed in many tropical areas due to invasive plants and competition with herbs. The cultivation of plants that are capable of maintaining a site can avoid the dominance of invasive species. Some native species of the genus Stylosanthes (family Fabaceae) have been reported to effectively block invasive plants off ecosystems that are under restoration in Brazil. The aim of this study was therefore to evaluate the influence of perennial Stylosanthes spp. on plant colonization in a rehabilitated gravel mine in the Brazilian savanna region. Half of the mining area was sown with a mixture of three perennial Styloshantes species (treatment), while half of it remained unsown (control). The line intercept method was used to sample recruited plants within the mine after five years of site rehabilitation. Results showed that 31 plant species recruited in the gravel mine: 27 in the area sown with Stylosanthes spp. and 17 in the control area. Native species contributed for 47 % of the importance value index (IVI) in the treated area and 26 % in the control area. Two invasive exotic grasses made up 31 % of the plant community IVI in the treated area and 59 % in the control area. Perennial Stylosanthes spp. were supposed to block the development of incoming plants, but their presence actually allowed the area to be colonized by 1.6-fold more plant species than the control area. Ultimately, the area covered with Stylosanthes spp. evolved into a plant community that was more diverse and less dominated by exotic species than the control area. 相似文献
464.
G Ambrosi G Nicolardi A Rizzi 《Bollettino della Società italiana di biologia sperimentale》1984,60(10):1897-1903
An immunocytochemical analysis was performed on the chicken medulla according to the PAP-DAB procedure, to study the distribution here of the neurons reacting to anti-VIP antibodies and the gliocytes reacting to anti-GFAP antibodies. Positive and negative controls were carried out in both the immunoreactions. The findings seem to indicate that more numerous VIP-immunoreactive neurons are located in the chicken than in the rat or mouse medulla, mainly in its intermediate 1/3, that VIP-immunoreactive fibres connect the medullar group of immunoreactive neurons with at least the first three cervical neuromeres, and confirm also for the chicken medulla, as already reported in other species by various researchers, the close relation of some VIP-immunoreactive neuronal processes with the small blood vessel walls, and the distribution of the GFAP-immunoreactive gliocytes. 相似文献
465.
466.
Giuseppe Giallongo Roberto Pilot Christian Durante Gian Andrea Rizzi Raffaella Signorini Renato Bozio Armando Gennaro Gaetano Granozzi 《Plasmonics (Norwell, Mass.)》2011,6(4):725-733
Commercially available digital versatile discs (DVDs) contain a silver-coated spiral distribution of rectangular-shaped grooves
(AgDVD): for the first time, they have been used to produce surface-enhanced Raman scattering (SERS) substrates by electrochemical
deposition of silver nanoparticles (AgNPs@AgDVD). The overall procedure only requires cheap and widely available materials
and can be easily accomplished. Scanning electron microscopy images of AgNPs@AgDVD revealed that small AgNPs (average diameter
about 15 nm) are present within the valleys of AgDVD, whereas over the ridges, the AgNPs are bigger, more densely packed and
with a dendrite-like morphology somewhere. The SERS properties of these substrates have been studied in terms of the enhancement
factor (EF), point-to-point reproducibility and sample-to-sample repeatability. It turned out that high SERS EF and good reproducibility
requirements are both fulfilled. As for repeatability, remarkably better results than typical literature values have been
achieved. Such an easy&cheap preparation along with efficient SERS properties make DVD-derived SERS substrates very good candidates for the development
of convenient and disposable sensing platforms. 相似文献
467.
Oliveira Thaís Larré Rizzi Caroline Dellagostin Odir Antônio 《Applied microbiology and biotechnology》2017,101(18):6865-6877
Applied Microbiology and Biotechnology - Recombinant Mycobacterium bovis BCG vaccines (rBCG) were first developed in the 1990s as a means of expressing antigens from multiple pathogens. This review... 相似文献