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Sunto Si fa l'analisi delle proiettività nello spazio hilbertiano riducendole a soli tre tipi aventi espressione analitica molto semplice. Fra i lavori cui, con singolare fervore, attendeva il compiantoGiuseppe Vitali nell'ultimo periodo della Sua laboriosa esistenza, una Memoria, dal titolo:Sulla proiettività dello spazio hilbertiano, era da Lui destinata agli ? Annali di Matematica ?. Per quanto la redazione non fosse stata da Lui interamente compiuta, pure manoscritti da Lui lasciati, e sopra tutto gli appunti di un corso di conferenze che Egli aveva tenuto presso l'Istituto matematico della R. Università di Bologna nell'anno 1930–31, redatti dalla Sua scolara Sig.na Emma Senigaglia e da Lui riveduti, hanno permesso a questa di darle la presente forma. La introduzione, premessa alla Memoria, era stata integralmente scritta dal compianto Maestro. Pubblicando questo lavoro postumo, la Redazione degli ? Annali ? intende di appagare un desiderio di uno Scienziato cui la matematica italiana deve un largo tributo di riconoscenza, e, nel tempo stesso, di rendere un doveroso omaggio alla di Lui memoria.  相似文献   
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Summary The use of the electrochemical detector (EC) in the high performance liquid chromatography (HPLC) of dansyl derivatives of biogenic amines is reported. Isocratic and gradient elution patterns of synthetic mixtures of putrescine, cadaverine, 1,6-diaminohexane, tryptamine, histamine, tyramine, spermine and spermidine on a reversed phase column are shown. Hydrodynamic voltammograms of standard compounds are presented. The detection limits of the EC are compared with those of ultraviolet and spectrofluorimetric detectors. A chromatographic profile of amines from the proteolytic catabolism of maize silage byClostridia is shown.Presented at the 17th International Symposium on Chromatography, September 25–30, 1988, Vienna, Austria.  相似文献   
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Optimized NMR experiments are developed for isolating magnetization belonging to the I=1/2 manifolds of 13CH3 methyl groups in proteins, enabling the manipulation of the magnetization of a 13CH3 moiety as if it were an AX (1H-13C) spin-system. These experiments result in the same ‘simplification’ of a 13CH3 spin-system that would be obtained from the production of {13CHD2}-methyl-labeled protein samples. The sensitivity of I=1/2 manifold-selection experiments is a factor of approximately 2 less than that of the corresponding experiments acquired on {13CHD2}-labeled methyl groups. The methodology described here is primarily intended for small-to-medium sized proteins, where the losses in sensitivity associated with the isolation of I=1/2 manifold transitions can be tolerated. Several NMR applications that benefit from simplification of the 13CH3 (AX3) spin-systems are described, with an emphasis on the measurements of methyl 1H-13C residual dipolar couplings in a {13CH3}-methyl-labeled deletion mutant of the human chaperone DNAJB6b, where modulation of NMR signal intensities due to evolution of methyl 1H-13C scalar and dipolar couplings follows a simple cosine function characteristic of an AX (1H-13C) spin-system, significantly simplifying data analysis.  相似文献   
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Breast cancer is one of the most diffuse cancers in the world and despite the availability of the different drugs employed against it, the need for new and particularly more specific molecules is ever growing. In this framework, natural products are increasingly assuming an important role as new anticancer drugs. Aloe-emodin (AE) is one of the best characterized molecules in this field. The functionalization of bioactive natural products with selected peptide sequences to enhance their bioavailability and specificity of action is a powerful and promising strategy. In this study, we analyzed the cell specificity, cell viability effects, intracellular distribution, and immune cell response of a new peptide conjugate of Aloe-emodin in SKBR3 and A549 cell lines by means of viability tests, flow cytometry, and confocal microscopy. The conjugate proved to be more effective at reducing cell viability than AE in both cell lines. Furthermore, the results showed that it was mainly internalized within the SKBR3 cells, showing a nuclear localization, while A459 cells displayed mainly a cytoplasmic distribution. A preserving effect of the conjugate on NKs’ cell function was also observed. The designed conjugate showed a promising specific activity towards HER2-expressing cells coupled with an enhanced water solubility and a higher cytotoxicity; thus, the resulting proof-of-concept molecule can be further improved as an anticancer compound.  相似文献   
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The carbonyl adduct of phthalocyaninatoiron(II), FePc, with N,N-dimethylformamide (DMF) as axial ligand, FePc(CO)DMF, was prepared by the reaction of iron carbonyls, Fe(CO)5 or Fe2(CO)9, with o-phthaalonitrile in DMF as solvent. Several carbonyl adducts of FePc of general formula FePc (CO)L are reported, with L being a ligand with oxygen, sulphur and nitrogen donor atoms (L = tetrahydrofuran, H2O, CH3OH, dimethylsulphoxide, tetrahydrothiophene, ammonia, n-propylamine, diethylamine, triethylamine). The crystal and molecular structure of FePc(CO)DMF·DMF was investigaed by X-ray diffraction methods. The compound has a monoclinic unit cell and space group P21/n, a 9.86(1), b 17.35(3), c 19.79(4) », β 87.9(2)°, Z = 4, U 3383 »3, D3 1.458 g cm?3. The iron atom is hexacoordinated to the four inner nitrogen atoms of the macrocyle, to carbon monoxide (Fe—C distance 1.72(2) ») and to DMF (Fe—O distance 2.07(1) »). The extra DMF occupies lattice sites. All of the compounds reported in this paper are substantially diamagnetic. Mössbauer spectra show typical isomer shift parameters for the bis-adducts and for the carbonyl adduct, substantially independent of the nature of the axial ligand. The quadrupole splitting parameter of the carbonyl adducts is strongly affected by the nature of the axial ligand.  相似文献   
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A rapid and selective method for the simultaneous determination of triazines and dinitroanilines in real water matrices is suggested based on a preliminary adsorption on an RP-18 cartridge, an elution step using acetonitrile and HPLC separation with a Lichrosorb RP- Select B column and UV detection. The washing step cartridge is critical for triazines: terbutryn is eluted with quantitative recovery only after washing with an NH3 solution. The degree of enrichment of the compounds studied has been determined: triazine recoveries are quantitative, while dinitroaniline recoveries are between 66% and 78% at the lowest fortification level. The detection limits for the ten herbicides are in the range 0.03-0.1 μg/l. The analysis time is 2 h.  相似文献   
130.
The interaction of a five-level atomic system involving electromagnetically induced transparency with four light fields is investigated. Two different light-atom configurations are considered, and their efficiency in generating large nonlinear cross-phase shifts compared. The dispersive properties of those schemes are analyzed in detail, and the conditions leading to group velocity matching for two of the light fields are identified. An analytical treatment based on amplitude equations is used in order to obtain approximate solutions for the susceptibilities, which are shown to fit well with the numerical solution of the full Bloch equations in a large parameter region.  相似文献   
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