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561.
Margherita De Rosa Sara Di Marino Anna Maria D’Ursi Maria Strianese Annunziata Soriente 《Tetrahedron》2012,68(14):3086-3091
The DNA molecule, recognized as the carrier of genetic information in vivo, can function as an efficient organocatalyst for Michael additions of 1,3-dicarbonyl compounds to activated alkenes in aqueous media. The procedure described here is environmentally benign and offers several advantages in terms of simplicity, generality and efficiency. We have used fluorescence spectroscopy to evaluate the catalytic activity of a molecule of DNA. 相似文献
562.
Giovanni Chiappetta Sega NDiaye Emmanuelle Demey Iman Haddad Gennaro Marino Angela Amoresano Joëlle Vinh 《Rapid communications in mass spectrometry : RCM》2010,24(20):3021-3032
Peptide tagging is a useful tool to improve matrix‐assisted laser desorption/ionization tandem mass spectrometric (MALDI‐MS/MS) analysis. We present a new application of the use of the dansyl chloride (DNS‐Cl). DNS‐Cl is a specific primary amine reagent widely used in protein biochemistry. It adds a fluorescent dimethylaminonaphthalene moiety to the molecule. The evaluation of MALDI‐MS and MS/MS analyses of dansylated peptides shows that dansylation raises the ionization efficiency of the most hydrophilic species compared with the most hydrophobic ones. Consequently, higher Mascot scores and protein sequence coverage are obtained by combining MS and MS/MS data of native and tagged samples. The N‐terminal DNS‐Cl sulfonation improves the peptide fragmentation and promotes the generation of b‐fragments allowing better peptide sequencing. In addition, we set up a labeling protocol based on the microwave chemistry. Peptide dansylation proved to be a rapid and cheap method to improve the performance of liquid chromatography (LC)/MALDI‐MS/MS analysis at the proteomic scale in terms of peptide detection and sequence coverage. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
563.
In Mazzocca et al. (Des. Codes Cryptogr. 44:97–113, 2007), large minimal blocking sets in PG(3, q 2) and PG(4, q 2) have been constructed starting from ovoids of PG(3, q), Q(4, q) and Q(6, q). Some of these can be embedded in a Hermitian variety as maximal partial ovoids. In this paper, the geometric conditions assuring these embeddings are established. 相似文献
564.
Gabriella Buscemi Andrea Biffis Cristina Tubaro Marino Basato Claudia Graiff Antonio Tiripicchio 《应用有机金属化学》2010,24(4):285-290
Chelating dicarbene complexes of palladium(II) and platinum(II) catalyse at room temperature with 1% catalyst loading the reaction of ethyl phenylpropiolate with aromatic heterocycles to yield synthetically useful intermediates for fine chemicals without the need to use prefunctionalized substrates. The reaction outcome was found to be strongly dependent on the nature of the anionic ligands at the metal complex. Addition of silver salts to replace halide ligands with more weakly coordinating anions improves the reaction yield and changes the product distributions: heterocycle? alkyne 2:1 adducts are obtained together with the usual hydroarylation products, which potentially broadens the scope of the reaction. The nature of the employed heterocycle, in particular its steric characteristics, is also found to strongly influence the outcome of the reaction. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
565.
Damaging in Al‐implanted 3C‐SiC and subsequent crystal recovery due to thermal treatments up to 1350 °C are evaluated by X‐ray diffraction and micro‐Raman spectroscopy. Reciprocal space mapping of (004) 3C‐SiC planes shows a low‐intensity implantation‐induced secondary peak at higher interplanar spacing in the as‐implanted 3C‐SiC sample, with a generated misfit between the implanted and the epitaxial region of about 0.6%. Increasing the annealing temperature from 950 °C to 1350 °C, the secondary peak is gradually re‐absorbed within the epitaxial 3C‐SiC reciprocal lattice point. Finally, the disappearance of the secondary peak after a 1350 °C thermal treatment is observed. Thus, implantation‐induced average strain, resulting in a severe 3C‐SiC deforma‐ tion, has been totally relieved at the highest annealing temperature. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
566.
Cristina Satriano Grazia M.L. Messina Clara Marino Ivana Aiello Enrico Conte Diego La Mendola Donatella A. Distefano Franca D’Alessandro Giuseppe Pappalardo Giuseppe Impellizzeri 《Journal of colloid and interface science》2010,341(2):232-239
The Pro-His-Ser-Arg-Asn (PHSRN) sequence in fibronectin is a second cell-binding site that synergistically affects Arg-Gly-Asp (RGD). The PHSRN peptide also induces cell invasion and accelerates wound healing. We report on the surface immobilization of PHSRN by spontaneous adsorption on polysiloxane thin films which have different surface free energy characteristics. Low-surface energy (hydrophobic) polysiloxane and the corresponding high-surface energy (hydrophilic) surfaces obtained by UV–ozone treatments were used as adsorbing substrates. The peptide adsorption process was investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy. Both adsorption kinetics and peptide rearrangement dynamics at the solid interface were significantly different on the surface-modified films compared to the untreated ones. Fibroblast cells cultures at short times and in a simplified environment, i.e., a medium-free solution, were prepared to distinguish interaction events at the interface between cell membrane and surface-immobilized peptide for the two cases. It turned out that the cell-adhesive effect of immobilized PHSRN was different for hydrophobic compared to hydrophilic ones. Early signatures of cell spreading were only observed on the hydrophilic substrates. These effects are explained in terms of different spatial arrangements of PHSRN molecules immobilized on the two types of surfaces. 相似文献
567.
568.
Marco Aurilia Filomena Piscitelli Luigi Sorrentino Marino Lavorgna Salvatore Iannace 《European Polymer Journal》2011,47(5):925-936
Organo-modified layered silicates (OMLSs) can largely improve mechanical properties of Thermoplastic polyurethanes (TPUs) as well as affect their microdomain morphology. Nanocomposite TPU containing OMLSs were prepared by melt blending at different concentrations. The addition of OMLS has both induced variation in enthalpy of melting of hard and soft phases, and influenced the glass transition temperature of soft domains, as result of the microdomain phase segregation measured by means of fourier transform infrared spectroscopy (FT-IR). Small angle X-ray scattering (SAXS) analysis has shown that the mean distance between hard domains was mostly unaffected by the filler. However, its distribution broadened with the increasing concentration of the OMLSs, resulting in increased extent of the hard domain interface. The storage modulus of TPU nanocomposites incremented with the silicate content, while the dynamic strain scan tests showed pronounced non linear viscoelastic behavior. The analysis of morphological data obtained by SAXS and FT-IR measurements were correlated to thermal and dynamic mechanical properties of TPU samples suggesting a crucial role of the soft domains interface. The storage modulus and loss tangent of TPU nanocomposites were found to increase with the increasing of the interface area of soft domains with both hard domains and OMLS stacks. 相似文献
569.
570.
Gomes Silva C Juárez R Marino T Molinari R García H 《Journal of the American Chemical Society》2011,133(3):595-602
Gold nanoparticles supported on P25 titania (Au/TiO(2)) exhibit photocatalytic activity for UV and visible light (532 nm laser or polychromatic light λ > 400 nm) water splitting. The efficiency and operating mechanism are different depending on whether excitation occurs on the titania semiconductor (gold acting as electron buffer and site for gas generation) or on the surface plasmon band of gold (photoinjection of electrons from gold onto the titania conduction band and less oxidizing electron hole potential of about -1.14 V). For the novel visible light photoactivity of Au/TiO(2), it has been determined that gold loading, particle size and calcination temperature play a role in the photocatalytic activity, the most active material (Φ(H2) = 7.5% and Φ(O2) = 5.0% at 560 nm) being the catalyst containing 0.2 wt % gold with 1.87 nm average particle size and calcined at 200 °C. 相似文献