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排序方式: 共有319条查询结果,搜索用时 328 毫秒
101.
Andrea Ienco Maria Caporali Ferdinando Costantino Annalisa Guerri Gabriele Manca Simonetta Moneti 《Journal of Coordination Chemistry》2014,67(23-24):3863-3872
Given the ability of forming homomeric amide···amide dimer by iso-nicotinamide (nda), we postulate the existence of a hydrogen bond equivalent of the iso-reticular metal organic nanotubes (MONT) built by using copper, p,p′-diphenylmethylene-diphosphinate (pcp), and bipyridine. We obtained the desired primary arrangement of Cu/pcp/nda consisting of a 1-D chain. Instead of the expected amide/amide dimer, the NH2 groups were engaged in H-bonding networks with the phosphinate ligands in a series of 2-D slabs. The differences and the similarities of the Cu/pcp chains in known MONTs and in the reported structure are also highlighted. 相似文献
102.
Fabio Mastrogiovanni Loredana Basiricò Umberto Bernabucci Margherita Campo Annalisa Romani 《Natural product research》2020,34(10):1465-1469
AbstractPomegranate peel extracts (PPE) were tested for the first time on BME-UV1, a valid cellular model to study the bovine mammary epithelial metabolism, to evaluate the effects on the oxidative stress and inflammatory status. Based on the statistical analysis of MTT data, PPE at 0.1, 1.0 and 10?μg/mL resulted not cytotoxic after 24?h, 48?h and 7 days of treatment. At the same concentrations, PPE induced a reduction of ROS production elicited by the addition of hydrogen peroxide or lipopolysaccharide evidencing an antioxidant effect confirmed also by a decrease of malondialdehyde. At 10?μg/mL, PPE reduced pro-inflammatory cytokines expressions showing an anti-inflammatory effect on BME-UV1 treated with lipopolysaccharide. Although in vivo experiments are necessary, the results of this study are promising for future applications of PPE as feed supplement for dairy cattle, in particular around calving, when the animals are more subject to oxidative stress and inflammatory diseases. 相似文献
103.
Marco Vigliano Annalisa Bianchera Ruggero Bettini Lisa Elviri 《Chromatographia》2013,76(23-24):1761-1766
Two simple and fast C18 and HILIC liquid chromatography–electrospray mass spectrometry methods for the determination of hyaluronic acid (HA) in a mucoadhesive chitosan-based formulation were developed and validated. The performances of both methods were compared in terms of validation parameters and matrix effect. A simple sample preparation method based on sulphuric acid-based degradation was optimized for the detection of HA fragments (i.e. m/z 380 2-mer, m/z 759 4-mer, m/z 1,138 8-mer and m/z 1,518 16-mer). By operating under selected ion-monitoring mode, excellent selectivity towards chitosan fragments was obtained. For validation, good linearity, detection limits (<4 μg mL?1) and precision (RSD % < 16 %) were generally obtained on matrix with both columns. However, HILIC column exhibited improved performances in terms of HA fragment separation and selectivity. By analyzing on the C18 column the chitosan-based formulation and sample extracts from pig mucosa treated with the formulation, matrix effects exhibited a dependence of signal suppression degree (ranging from 37 to 83 %) as a function of the HA fragment dimension. The HILIC column afforded instead a significantly reduced suppression degree (ranging from 1 to 16 %) and a better separation. These findings demonstrated the improved performances of the HILIC column with respect to conventional C18 mechanism for the analysis of HA fragments in complex matrices. 相似文献
104.
In this paper, we prove Poincaré and Sobolev inequalities for differential forms in L~1(R~n). The singular integral estimates that it is possible to use for L~p, p 1, are replaced here with inequalities which go back to Bourgain and Brezis(2007). 相似文献
105.
Antonino Lauria Annalisa Guarcello Gaetano Dattolo Anna Maria Almerico 《Tetrahedron letters》2008,49(11):1847-1850
Various derivatives of the heterocyclic system 1,12,12a,12b-tetrahydrobis-1,2,4-triazolo[4,3-a:3′,4′-c]quinoxaline of pharmaceutical interest have been obtained by double site- and regio-selective 1,3-dipolar cycloaddition of arylnitrilimines to quinoxalines. No evidence for the formation of mono-adducts was obtained, at variance with literature reports. Specific studies to establish the exact stereochemistry of the bis-cycloadducts were undertaken. 相似文献
106.
Akhil Venugopal Dr. Lorena Ruiz-Perez Dr. K. Swamynathan Dr. Chidambar Kulkarni Dr. Annalisa Calò Dr. Mohit Kumar 《Angewandte Chemie (International ed. in English)》2023,62(8):e202208681
Supramolecular systems chemistry has been an area of active research to develop nanomaterials with life-like functions. Progress in systems chemistry relies on our ability to probe the nanostructure formation in solution. Often visualizing the dynamics of nanostructures which transform over time is a formidable challenge. This necessitates a paradigm shift from dry sample imaging towards solution-based techniques. We review the application of state-of-the-art techniques for real-time, in situ visualization of dynamic self-assembly processes. We present how solution-based techniques namely optical super-resolution microscopy, solution-state atomic force microscopy, liquid-phase transmission electron microscopy, molecular dynamics simulations and other emerging techniques are revolutionizing our understanding of active and adaptive nanomaterials with life-like functions. This Review provides the visualization toolbox and futuristic vision to tap the potential of dynamic nanomaterials. 相似文献
107.
108.
de Ceglia D D'Orazio A De Sario M Petruzzelli V Prudenzano F Centini M Cappeddu MG Bloemer MJ Scalora M 《Optics letters》2007,32(3):265-267
We study second-harmonic generation in a negative-index material cavity. The transmission spectrum shows a bandgap between the electric and magnetic plasma frequencies. The nonlinear process is made efficient by local phase-matching conditions between a forward-propagating pump and a backward-propagating second-harmonic signal. By simultaneously exciting the cavity with counterpropagating pulses, and by varying their relative phase difference, one is able to enhance or inhibit linear absorption and the second-harmonic conversion efficiency. 相似文献
109.
Carfagna C Gatti G Mosca L Passeri A Paoli P Guerri A 《Chemical communications (Cambridge, England)》2007,(43):4540-4542
Structural analysis of the first steps of isotactic CO/p-methylstyrene copolymerisation, catalysed by aryl-alpha-diimine Pd(II) complexes, highlights the influence of steric effects on the stereoselectivity of olefin insertion. 相似文献
110.
Interactions of pyridinecarboxylic acid chelators with brain metal ions: Cu(II), Zn(II), and Al(III)
éva Sija Annalisa Dean Tamás Jakusch Valerio B. Di Marco Alfonso Venzo Tamás Kiss 《Monatshefte für Chemie / Chemical Monthly》2011,35(8):399-410