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131.
Mannini M Tancini E Sorace L Sainctavit P Arrio MA Qian Y Otero E Chiappe D Margheriti L Cezar JC Sessoli R Cornia A 《Inorganic chemistry》2011,50(7):2911-2917
Surface-supported arrays of Fe(4)-type Single-Molecule Magnets retain a memory effect and are of current interest in the frame of molecule-based information storage and spintronics. To reveal the spin structure of [Fe(4)(L)(2)(dpm)(6)] (1) on Au, an isomorphous compound [Fe(3)Cr(L)(2)(dpm)(6)] was synthesized and structurally and magnetically characterized (H(3)L is tripodal ligand 11-(acetylthio)-2,2-bis(hydroxymethyl)undecan-1-ol and Hdpm is dipivaloylmethane). The new complex contains a central Cr(3+) ion and has a S = 6 ground state as opposed to S = 5 in 1. Low-temperature X-ray Magnetic Circular Dichroism studies at Fe- and Cr-L(2,3) edges revealed that the antiparallel alignment between Fe and Cr spins is preserved on surfaces. Moreover, the different Fe-L(2,3) spectral features found in the homo- and heterometallic species disclose the opposing contribution of the central Fe(3+) ion in the former compound, proving that its ferrimagnetic spin structure is retained on surfaces. 相似文献
132.
Menichini F Tundis R Bonesi M de Cindio B Loizzo MR Conforti F Statti GA Menabeni R Bettini R Menichini F 《Natural product research》2011,25(8):789-799
The chemical composition of the essential oil of Citrus medica L. cv. Diamante peel obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction techniques was determined by GC/MS analysis. Forty-six components were fully characterised. Limonene and γ-terpinene were the major components of the oils obtained by hydrodistillation (HD) and cold-pressing (CP), while citropten was the major constituent in the oil obtained by supercritical carbon dioxide extraction (SFE). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities were evaluated. The essential oil obtained by hydrodistillation exerted the highest inhibitory activity against BChE (IC?? value of 154.6 μg mL?1) and AChE (IC?? value of 171.3 μg mL?1. Interestingly, the oil obtained by cold-pressing exhibited a selective inhibitory activity against AChE. The essential oils have also been evaluated for the inhibition of NO production in LPS induced RAW 264.7 macrophages. The oil obtained by hydrodistillation exerted a significant inhibition of NO production with an IC?? value of 17 μg mL?1 (IC?? of positive control 53 μg mL?1). 相似文献
133.
Yasser M. Loksha Daniel Globisch Erik B. Pedersen Paolo La Colla Gabriella Collu Roberta Loddo 《Journal of heterocyclic chemistry》2008,45(4):1161-1166
1,5‐Disubstituted pyrimidine‐2,4‐diones were synthesized by fusion of 5‐bromouracil with an aniline derivative followed by coupling with benzyl halide whereas the opposite synthesis sequence failed. Also 4,6‐dichloro‐N,N,5‐trimethylpyrimidin‐2‐amine was treated with phenols. The products were tested for their activity against HIV‐1. 相似文献
134.
Adriana González Castro José Sánchez Costa Roberta Pievo Chiara Massera Ilpo Mutikainen Urho Turpeinen Patrick Gamez Jan Reedijk Prof. Dr. 《无机化学与普通化学杂志》2008,634(14):2477-2482
A new Schiff‐base ligand having a potentially coordinating thioether group (2‐quinoline‐N‐(2′‐methylthiophenyl)methyleneimine, qmtpm ) has been prepared. The synthesis, structure, UV‐Vis and EPR studies of one copper(II) and two cobalt(II) complexes from this ligand is reported. The X‐ray structures of the CuII and CoII chlorido complexes 1 and 2 reveal the metal atoms in highly distorted square‐pyramidal environments constituted of one tridentate ligand and two anions. On the other hand, the thiocyanato CoII compound 3 exhibits a distorted trigonal‐bipyramidal structure. These structural variations are apparently due to the different counter‐ions which leads to distinct lattice interactions. The spectroscopic data obtained by EPR and UV‐Vis investigations are in agreement with the solid‐state structures of the coordination compounds. 相似文献
135.
Adsorption and stability of streptavidin on cluster-assembled nanostructured TiOx films 总被引:1,自引:0,他引:1
Giorgetti L Bongiorno G Podestà A Berlanda G Scopelliti PE Carbone R Milani P 《Langmuir : the ACS journal of surfaces and colloids》2008,24(20):11637-11644
The study of the adsorption of proteins on nanostructured surfaces is of fundamental importance to understand and control cell-surface interactions and, notably, cell adhesion and proliferation; it can also play a strategic role in the design and fabrication of nanostructured devices for postgenomic and proteomic applications. We have recently demonstrated that cluster-assembled nanostructured TiO x films produced by supersonic cluster beam deposition possess excellent biocompatibility and that these films can be functionalized with streptavidin, allowing the immobilization of biotinylated retroviral particles and the realization of living-cell microarrays for phenotype screening. Here we present a multitechnique investigation of the adsorption mechanisms of streptavidin on cluster-assembled TiO x films. We show that this nanostructured surface provides an optimal balance between adsorption efficacy and protein functionality. By using low-resolution protein arrays, we demonstrate that a layer of adsorbed streptavidin can be stably maintained on a cluster-assembled TiO x surface under cell culture conditions and that streptavidin retains its biological activity in the adsorbed layer. The adsorption mechanisms are investigated by atomic force microscopy in force spectroscopy mode and by valence-band photoemission spectroscopy, highlighting the potential role of the interaction of the exposed carboxyl groups on streptavidin with the titanium atoms of the nanostructured surface. 相似文献
136.
Perspectives in paramagnetic NMR of metalloproteins 总被引:1,自引:0,他引:1
Bertini I Luchinat C Parigi G Pierattelli R 《Dalton transactions (Cambridge, England : 2003)》2008,(29):3782-3790
NMR experiments and tools for the characterization of the structure and dynamics of paramagnetic proteins are presented here. The focus is on the importance of (13)C direct-detection NMR for the assignment of paramagnetic systems in solution, on the information contained in paramagnetic effects observed both in solution and in the solid state, and on novel paramagnetism-based tools for the investigation of conformational heterogeneity in protein-protein complexes or in multi-domain proteins. 相似文献
137.
Squeglia F Marchetti R Ruggiero A Lanzetta R Marasco D Dworkin J Petoukhov M Molinaro A Berisio R Silipo A 《Journal of the American Chemical Society》2011,133(51):20676-20679
Bacterial Ser/Thr kinases modulate a wide number of cellular processes. In Bacillus subtilis , the Ser/Thr kinase PrkC has been shown to induce germination of bacterial spores in response to DAP-type but not Lys-type cell wall muropeptides. Muropeptides are a clear molecular signal that growing conditions are promising, since they are produced during cell wall peptidoglycan remodeling associated with cell growth and division of neighboring bacteria. However, whether muropeptides are able to bind the protein physically and how the extracellular region is able to distinguish the two types of muropeptides remains unclear. Here we tackled the important question of how the extracellular region of PrkC (EC-PrkC) senses muropeptides. By coupling NMR techniques and protein mutagenesis, we exploited the structural requirements necessary for recognition and binding and proved that muropeptides physically bind to EC-PrkC through DAP-moiety-mediated interactions with an arginine residue, Arg500, belonging to the protein C-terminal PASTA domain. Notably, mutation of this arginine completely suppresses muropeptide binding. Our data provide the first molecular clues into the mechanism of sensing of muropeptides by PrkC. 相似文献
138.
Electrodes/Electrolyte Interfaces in the Presence of a Surface‐Modified Photopolymer Electrolyte: Application in Dye‐Sensitized Solar Cells 下载免费PDF全文
Dr. Adriano Sacco Federico Bella Stefano De La Pierre Dr. Micaela Castellino Dr. Stefano Bianco Prof. Roberta Bongiovanni Prof. Candido Fabrizio Pirri 《Chemphyschem》2015,16(5):960-969
Since hundreds of studies on photoanodes and cathodes show that the electrode/electrolyte interfaces represent a key aspect at the base of dye‐sensitized solar cell (DSSC) performances, it is reported here that these interfaces can be managed by a smart design of the spatial composition of quasi‐solid electrolytes. By means of a cheap, rapid, and green process of photoinduced polymerization, composition‐tailored polymer electrolyte membranes (PEMs) with siloxane‐enriched surfaces are prepared, and their properties are thoroughly described. When assembled in DSSCs, the interfacial action promoted by the composition‐tailored PEMs enhances the photocurrent and fill factor values, thus increasing the global photovoltaic conversion efficiency with respect to the non‐modified PEMs. Moreover, the presence of the siloxane‐chain‐enriched surface increases the hydrophobicity and reduces the water vapor permeation into the device, thus enhancing the cell′s durability. 相似文献
139.
Maria Ciaccia Irene Tosi Laura Baldini Roberta Cacciapaglia Luigi Mandolini Stefano Di Stefano Christopher A. Hunter 《Chemical science》2015,6(1):144-151
A new strategy for determining thermodynamic effective molarities (EM) for macrocylisation reactions using dynamic combinatorial chemistry under dilute conditions is presented. At low concentrations, below the critical value, Dynamic Libraries (DLs) of bifunctional building blocks contain only cyclic species, so it is not possible to quantify the equilibria between linear and cyclic species. However, addition of a monofunctional chain stopper can be used to promote the formation of linear oligomers allowing measurement of EM for all cyclic species present in the DL. The effectiveness of this approach was demonstrated for DLs generated from mixtures of 1,3-diimine calix[4]arenes, linear diaminoalkanes and monoaminoalkanes. For macrocycles deriving from one bifunctional calixarene and one diamine, there is an alternating pattern of EM values with the number of methylene units in the diamine: odd numbers give significantly higher EMs than even numbers. For odd numbers of methylene units, the alkyl chain can adopt an extended all anti conformation, whereas for even numbers of methylene units, gauche conformations are required for cyclisation, and the associated strain reduces EM. The value of EM for the five-carbon linker indicates that this macrocycle is a strainless ring. 相似文献
140.
HPLC‐MS/MS method for quantitative determination of the novel dual inhibitor of FGF and VEGF receptors E‐3810 in tumor tissues from xenograft mice and human biopsies 下载免费PDF全文
Monique Zangarini Laura Ceriani Ezia Bello Giovanna Damia Roberta Cereda Maria Gabriella Camboni Massimo Zucchetti 《Journal of mass spectrometry : JMS》2014,49(1):19-26
We developed and validated a high‐performance liquid chromatography–tandem mass spectrometry analytical method to measure E‐3810, a novel dual inhibitor of fibroblast growth factor receptor 1 and vascular endothelial growth factor receptor 1–3 in tissues and determined the drug concentration in a biopsy of human breast cancer for the first time. The method is a modification of our previous one in plasma to study the clinical pharmacokinetics of the drug during the phase I/II trial. In view of the changes in matrix, we applied a partial validation protocol to determine recovery, sensitivity, range of linearity, precision, accuracy and stability of the method over three runs in a mouse tumor tissue and liver. The recovery of E‐3810 from liver or tumor homogenate was >69%, and the lower limit of quantification was 5 ng/ml. The method was linear in the concentration range 5.0–500.0 ng/ml, as demonstrated by a determination coefficient R2 ≥ 0.9955. The range of the calibration curve was appropriate for the analysis, as demonstrated by the accuracy, which was between 91.4% and 106.7%. Interday precision and accuracy on quality control samples at 9, 30 and 300 ng/ml were 3.1‐11.2% and 98.3–111.4%, respectively. The assay was applied successfully to determine the intratumor concentration of E‐3810 in different mouse xenograft tumor models and in a biopsy of a patient with breast cancer included in the phase I/II trial of the drug. In mouse tumors, the concentrations of E‐3810 were higher than necessary to exert antitumor activity in vitro (1 µM). Even more of interest was the result obtained in a human biopsy of few milligrams, where E‐3810 reached 4.9 µg/g (11 µM). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献