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991.
Gale PA Navakhun K Camiolo S Light ME Hursthouse MB 《Journal of the American Chemical Society》2002,124(38):11228-11229
Two molecules containing two 2,5-diamido,3,4-dichloropyrrole units linked via 1,3- or 1,4-substituted benzene rings have been synthesized. The pyrrole groups in these compounds deprotonate in the presence of tetrabutylammonium fluoride and form pyrrole anion dimers via NH...N- hydrogen bonds. This dimerization process results in the formation of polyanionic chains linked via an unusual "orthogonal" hydrogen-bonding array. 相似文献
992.
Roda A Roda B Cevenini L Michelini E Mezzanotte L Reschiglian P Hakkila K Virta M 《Analytical and bioanalytical chemistry》2011,401(1):201-211
Whole-cell bioluminescent (BL) bioreporter technology is a useful analytical tool for developing biosensors for environmental
toxicology and preclinical studies. However, when applied to real samples, several methodological problems prevent it from
being widely used. Here, we propose a methodological approach for improving its analytical performance with complex matrix.
We developed bioluminescent Escherichia coli and Saccharomyces cerevisiae bioreporters for copper ion detection. In the same cell, we introduced two firefly luciferases requiring the same luciferin
substrate emitting at different wavelengths. The expression of one was copper ion specific. The other, constitutively expressed,
was used as a cell viability internal control. Engineered BL cells were characterized using the noninvasive gravitational
field-flow fractionation (GrFFF) technique. Homogeneous cell population was isolated. Cells were then immobilized in a polymeric
matrix improving cell responsiveness. The bioassay was performed in 384-well black polystyrene microtiter plates directly
on the sample. After 2 h of incubation at 37 °C and the addition of the luciferin, we measured the emitted light. These dual-color
bioreporters showed more robustness and a wider dynamic range than bioassays based on the same strains with a single reporter
gene and that uses a separate cell strain as BL control. The internal correction allowed to accurately evaluate the copper
content even in simulated toxic samples, where reduced cell viability was observed. Homogenous cells isolated by GrFFF showed
improvement in method reproducibility, particularly for yeast cells. The applicability of these bioreporters to real samples
was demonstrated in tap water and wastewater treatment plant effluent samples spiked with copper and other metal ions. 相似文献
993.
Comparative two-dimensional mapping of prion protein isoforms in human cerebrospinal fluid and central nervous system 总被引:3,自引:0,他引:3
Castagna A Campostrini N Farinazzo A Zanusso G Monaco S Righetti PG 《Electrophoresis》2002,23(2):339-346
The cellular prion protein (PrP(C)) is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein abundant in neurons. Although its precise function is unknown, PrP(C) represents the substrate for the generation of a conformational pathogenic isoform (PrP(Sc)) in human and animal transmissible spongiform encephalopathies, or prion diseases. By applying novel solubilization cocktails, we analyzed normal human brain and cerebrospinal fluid (CSF) PrP(C) by immunoblot of two-dimensional (2-D) gel electrophoresis preparations, using specific antibodies. Here, we show that PrP(C) from brain and CSF is composed of several charge isomers of differently glycosylated isoforms of the full-length PrP(C) and two N-terminally truncated fragments of 20 and 18 kDa. In the CSF, substantial amounts of the highly glycosylated PrP(C) isoforms and of the unglycosylated 18 kDa fragment are detected. Our study, for the first time, provides a detailed 2-D map of human PrP(C) both in brain and CSF, and establishes an innovative and sensitive method that might help in detecting the CSF pathological PrP(Sc) isoform in vivo. It also shows the incredible microheterogeneity of such isoforms (ca. 60 spots!), as revealed in 2-D mapping, as opposed to 3-4 main zones by mono-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). 相似文献
994.
Michael Tsamparlis Andronikos Paliathanasis Spyros Basilakos Salvatore Capozziello 《General Relativity and Gravitation》2013,45(10):2003-2022
Conformally related metrics and Lagrangians are considered in the context of scalar–tensor gravity cosmology. After the discussion of the problem, we pose a lemma in which we show that the field equations of two conformally related Lagrangians are also conformally related if and only if the corresponding Hamiltonian vanishes. Then we prove that to every non-minimally coupled scalar field, we may associate a unique minimally coupled scalar field in a conformally related space with an appropriate potential. The latter result implies that the field equations of a non-minimally coupled scalar field are the same at the conformal level with the field equations of the minimally coupled scalar field. This fact is relevant in order to select physical variables among conformally equivalent systems. Finally, we find that the above propositions can be extended to a general Riemannian space of $n$ n -dimensions. 相似文献
995.
Salvatore A. Marano 《Set-Valued Analysis》1995,3(2):167-180
For a class of elliptic boundary value problems with discontinuous nonlinearities, the existence of strong solutions is established. Two applications are then developed. In particular, one of them is devoted to implicit elliptic equations of the form (–u)=(u), where is a continuous function and has a set of discontinuity points of Lebesgue measure zero. The abstract framework where these problems are studied is that of set-valued analysis. 相似文献
996.
Takeshi Saito Sigurd Wenner Elisa Osmundsen Calin D. Marioara Sigmund J. Andersen Jostein Røyset 《哲学杂志》2013,93(21):2410-2425
Effects of addition of Zn (up to 1 wt%) on microstructure, precipitate structure and intergranular corrosion (IGC) in an Al–Mg–Si alloys were investigated. During ageing at 185?°C, the alloys showed modest increases in hardness as function of Zn content, corresponding to increased number densities of needle-shaped precipitates in the Al–Mg–Si alloy system. No precipitates of the Al–Zn–Mg alloy system were found. Using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), the Zn atoms were incorporated in the precipitate structures at different atomic sites with various atomic column occupancies. Zn atoms segregated along grain boundaries, forming continuous film. It correlates to high IGC susceptibility when Zn concentration is ~1wt% and the materials in peak-aged condition. 相似文献
997.
Camillo?TrapaniEmail author Salvatore?Triolo 《Mediterranean Journal of Mathematics》2004,1(4):441-461
The possibility of extending the well known Gelfand–Naimark–Segal representation of *-algebras to certain Banach C*-modules is studied. For this aim the notion of modular biweight on a Banach C*-module is introduced. For the particular class of strict pre CQ*-algebras, two different types of representations are investigated. 相似文献
998.
S. Arumugam K. Mydeen N. Manivannan K.U. RamaTulasi Elisa Baggio Saitovitch A.T. Boothroyd 《Solid State Communications》2005,136(5):292-296
We report the temperature dependence of susceptibility for various pressures, magnetic fields and constant magnetic field of 5 T with various pressures on La2−2xSr1+2xMn2O7 single crystal to understand the effectiveness of pressure and magnetic field in altering the magnetic properties. We find that the Curie temperature, Tc, increases under pressure (dTc/dP=10.9 K/GPa) and it indicates the enhancement of ferromagnetic phase under pressure up to 2 GPa. The magnetic field dependence of Tc is about 26 K for 3 T. The combined effect of pressure and constant magnetic field (5 T) shows dTc/dP=11.3 K/GPa and the peak structure is suppressed and broadened. The application of magnetic field of 5 T realizes 3D spin ordered state below Tc at atmospheric pressure. Both peak structure in χc and 3D spin ordered state are suppressed, and changes to 2D-like spin ordered state by increase of pressure. These results reveal that the pressure and the magnetic field are more competitive in altering the magnetic properties of bilayer manganite La1.25Sr1.75Mn2O7 single crystal. 相似文献
999.
Several pyridofuroxans were obtained by spontaneous N2 elimination from the corresponding 2-azido-3-nitropyridines. In this particular case, the presence of nitrogen in the pyridine ring must facilitate a cyclic extrusion mechanism. The pyridofuroxans prepared in this study did not present tautomerism as evidenced by NMR. 相似文献
1000.
Massimo Riccio Elisa Resca Laura Bertoni Francesco Cavani Paola Sena Marzia Ferretti Andrea Baldini Carla Palumbo Anto De Pol 《Optics & Laser Technology》2011,43(2):317-322
Colour is not related to a particular discipline, but it is transversely present in many circles and in almost all the aspects of life. It has a special value in art, but also as far as other disciplines are concerned, like the sciences, the colour is at the basis of some of their intrinsic significances and it often needed to allow the interpretation of some of their phenomena as well. As regards the development of cell biology knowledge, colour acquired more and more importance in revealing the observations of the researchers. A field in which the methods based on the colours are particularly employed is the immunofluorescence, used to identify specific proteins in cells and tissues. These techniques combine the fluorochrome properties with specific molecules, i.e. antibodies, directed against particular substances to investigate, for example a specific protein. In single immunofluorescence analysis, the signal from an excited fluorochrome corresponds to a particular protein. In multiple immunofluorescence analysis, two or more signals are simultaneously detected to show the localization of different proteins on the same sample. The three primary colours red, green and blue were currently assigned to the signals from immunofluorescence-processed samples and visualized by the RGB method. In the present work, different examples of RGB applications in immunocytochemical investigations are showed: the first concerns the multiple analysis of three markers, localized in different loci of the cell plasma membrane; the second is related to the co-localization of two signals in the same site of specific subcellular structures. In this case the secondary colours, obtained by overlapping the primary ones, demonstrate the specific co-presence of two proteins in the same site. With the present paper, the authors wish to underline the relevant role of colours also in those areas in which colours are the means not the end. 相似文献