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101.
Angela Chambery Antimo Di Maro Carmen Sanges Valeria Severino Maura Tarantino Annalisa Lamberti Augusto Parente Paolo Arcari 《Analytical and bioanalytical chemistry》2009,395(7):2281-2291
Diagnostic techniques applied to the field of cultural heritage represent a very important aspect of scientific investigation.
Recently, proteomic approaches based on mass spectrometry coupled with traditional spectroscopic methods have been used for
painting analysis, generating promising results for binder’s protein identification. In the present work, an improved procedure
based on LC-ESI/Q-q-TOF tandem mass spectrometry for the identification of protein binders has been developed for the molecular
characterization of samples from an early-twentieth-century mural painting from the St. Dimitar Cathedral in Vidin, Bulgaria.
The proteomic investigation has led to the identification of both egg white and egg yolk proteins, according to traditional
old recipes for tempera paintings. In addition, beyond the egg components, the presence of caseins was also revealed, thus
suggesting the use of milk as binding medium, fixative or stabilising agent. Furthermore, for the first time, the capability
to discriminate the milk origin on the basis of alpha casein proteotypic peptides is reported, that are diagnostic for a given
species, thus opening interesting perspectives in art and archaeological fields. 相似文献
102.
Elena Angelini Francesco Galuppi Massimiliano Mella Giorgio Ottaviani 《Journal of Pure and Applied Algebra》2018,222(4):950-965
We prove that a general polynomial vector in three homogeneous variables of degrees has a unique Waring decomposition of rank 7. This is the first new case we are aware of, and likely the last one, after five examples known since the 19th century and the binary case. We prove that there are no identifiable cases among pairs in three homogeneous variables of degree , unless , and we give a lower bound on the number of decompositions. The new example was discovered with Numerical Algebraic Geometry, while its proof needs Nonabelian Apolarity. 相似文献
103.
In this paper we introduce a discretization methodology for Maxwell equations based on Mimetic Finite Differences (MFD). Following the lines of the recent advances in MFD techniques (see Brezzi et al. (2007) [14] and the references therein) and using some of the results of Brezzi and Buffa (2007) [12], we propose mimetic discretizations for several formulations of electromagnetic problems both at low and high frequency in the time-harmonic regime. The numerical analysis for some of the proposed discretizations has already been developed, whereas for others the convergence study is an object of ongoing research. 相似文献
104.
Palumbo Piccionello A Guarcello A Buscemi S Vivona N Pace A 《The Journal of organic chemistry》2010,75(24):8724-8727
The reaction of various 1,2,4-oxadiazoles with an excess of hydrazine in DMF has been investigated. 3-Amino-1,2,4-triazoles are produced through a reductive ANRORC pathway consisting of the addition of hydrazine to the 1,2,4-oxadiazole followed by ring-opening, ring-closure, and final reduction of the 3-hydroxylamino-1,2,4-triazole intermediate. The general applicability of 1,2,4-oxadiazoles ANRORC reactivity is demonstrated also in the absence of C(5)-linked electron-withdrawing groups. 相似文献
105.
Lucia Ambrosio M. Carla Aragoni Dr. Massimiliano Arca Dr. Francesco A. Devillanova Prof. Michael B. Hursthouse Prof. Dr. Susanne L. Huth Dr. Francesco Isaia Prof. Vito Lippolis Prof. Dr. Annalisa Mancini Dr. Anna Pintus Dr. 《化学:亚洲杂志》2010,5(6):1395-1406
The tetrabutylammonium (TBA+) salts of square‐planar monoanionic gold complexes of the unsymmetrically substituted Ar,H‐edt2? 1,2‐dithiolene ligands (Ar,H‐edt2?=arylethylene‐1,2‐dithiolato; Ar=phenyl ( 1 ?), 2‐naphthyl ( 2 ?), and 1‐pyrenyl ( 3 ?)) were synthesized and characterized by spectroscopic and electrochemical methods and the corresponding neutral species ( 1 , 2 , and 3 , respectively) were obtained in CH2Cl2 solution at room temperature by diiodine oxidation. The single‐crystal X‐ray diffraction structural data collected for (TBA+)( 2 ?), supported by DFT theoretical calculations, are consistent with the ene‐1,2‐dithiolate form of the ligand and the AuIII oxidation state. All complexes feature intense near‐IR absorptions (at about 1.5 μm) in their neutral states and Vis‐emitting properties in the 400–550 nm range, the energy of which is controlled by the charge of the complex in the case of the 3 ?/ 3 couple. The spectroscopic and electrochemical features of 1 x? and 2 x? (x=0, 1), both in their cis and trans conformations, were investigated by means of DFT and time‐dependent (TD) DFT calculations. 相似文献
106.
Romani A Vignolini P Tanini A Pampaloni B Heimler D 《Natural product communications》2010,5(11):1775-1780
Isoflavones are polyphenolic compounds found mainly in legumes the benefits of which have been widely studied and attributed in particular to their phytoestrogenic activity. The aim of this study was to evaluate the quali-quantitative composition of food supplements based on soy isoflavones (Glycine max L.) and red clover (Trifolium pratense). Six commercial food supplements (five soy-based and one red clover-based) were analyzed by HPLC/DAD/MS. Genistein, daidzein, glycitein, biochanin A and formononetin derivatives (glycosides and acylglycosides) were identified in the analyzed samples. Also the antiradical activities (towards the DPPH* radical) and Fe2+ chelating abilities were compared. 相似文献
107.
Asymmetric radiation-induced inclusion polymerization of 3-methyl-1,4-pentadiene in deoxycholic acid
The radiation-induced polymerization of 3-methyl-1,3-pentadiene (3MPD) as an inclusion complex in deoxycholic acid (DOCA) has produced in good yield the optically active polymer poly(3-methyl-1,4-pentadiene) (P3MPD) whose structure and properties were studied by FT-IR spectroscopy and thermal analysis (TGA, DTG and DTA). The data show that the polymer is essentially trans-1,4-P3MPD as expected for the polymerization in constrained media. Trans-1,4-P3MPD is optically active with [α]D values comprised between +4.3 and +5.6. The optical rotatory dispersion curve of the P3MPD is completely different from that of DOCA as expected. 相似文献
108.
109.
The theory of non-uniform flexure and torsion of Saint-Venant's beam with arbitrary multiply connected cross section is revisited in a coordinate-free form to provide a computationally convenient context. Numerical implementations, by Matlab, are performed to evaluate the maximum elastic shear stresses in beams with rectangular cross sections for different Poisson's ratios. The deviations between the maximum and mean stresses are then diagrammed to adjust the results provided by Jourawski's method. 相似文献
110.
Valerio B. Di Marco Luca Raveane Annalisa Dean Pietro Traldi 《Rapid communications in mass spectrometry : RCM》2010,24(7):868-874
Electrospray ionization mass spectrometry (ESI‐MS) is very often employed to study metal/ligand equilibria in aqueous solution. However, the ionization process can introduce perturbations which affect the speciation results in an unpredictable way. It is necessary to identify these perturbations in order to correctly interpret the ESI‐MS speciation results. Aluminium(III)/1,6‐dimethyl‐4‐hydroxy‐3‐pyridinecarboxylate (DQ716) aqueous solutions at various pH were analysed by ESI‐MS, and speciation results were compared with those obtained by equilibrium techniques. Differences observed were both qualitative and quantitative. The ESI‐MS spectral changes due to different settings of the following instrumental parameters were analyzed: the solution flow rate (FS), the nebulizer gas flow rate (FG), the potential applied at the entrance capillary (EC), and the temperature of the drying gas (TG). The effects produced by FS and EC on the spectra strongly suggest the key role of surface activity in determining the relative fraction of the ions reaching the detector. The experimental effects of FS and TG were interpreted considering the presence of at least two reactions in the gas phase and a dimerization occurring in the droplets. These perturbations cannot be generalized because they appear to be chemical system‐related and instrument‐dependent. Therefore, the identification of perturbations is a required task for any metal‐ligand equilibrium study performed by ESI‐MS. Our results indicate that perturbations can be identified by evaluating the effects produced in the spectra by a change of instrumental parameters. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献