Search results for "Lode"
showing 10 items of 343 documents
Convenient Photochemical Synthesis of Silver-Polyaminocyclodextrin Nanocomposites: The Role of the Light Source from a Mechanistic Viewpoint
2018
An investigation on the light-driven reduction of the [Ag(NH3)2]+complex in the presence of polyaminocyclodextrins was carried out, in order to clarify the mechanism of the process. The role of the organic auxiliary as both the sacrificial reductant and the capping agent was positively assessed. Moreover, particular attention was paid to the role of the irradiation source. Experimental results indicate that a complex mechanism is involved in the formation of the nanocomposite, with a primary photoinduced single-electron-transfer process promoted by irradiation with green light, followed by a secondary chemical reduction process activated by NIR. Representative composites were characterized …
Early signaling network in tobacco cells elicited with methyl jasmonate and cyclodextrins.
2012
We analyze, for the first time, the early signal transduction pathways triggered by methyl jasmonate (MJ) and cyclodextrins (CDs) in tobacco (Nicotiana tabacum) cell cultures, paying particular attention to changes in cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)), the production of hydrogen peroxide (H(2)O(2)) and nitric oxide (NO), and late events like the induction of capsidiol. Our data indicate that MJ and CDs trigger a [Ca(2+)](cyt) rise promoted by Ca(2+) influx through Ca(2+)-permeable channels. The joint presence of MJ and CDs provokes a first increase in [Ca(2+)](cyt) similar to that observed in MJ-treated cells, followed by a second peak similar to that found in the presence…
On the zopiclone enantioselective binding to human albumin and plasma proteins. An electrokinetic chromatography approach
2011
In this work, a methodology for the chiral separation of zopiclone (ZPC) by electrokinetic chromatography (EKC) using carboxymethylated-β-cyclodextrin as chiral selector has been developed and applied to the evaluation of the enantioselective binding of ZPC enantiomers to HSA and total plasma proteins. Two mathematical approaches were used to estimate protein binding (PB), affinity constants (K(1)) and enantioselectivity (ES) for both enantiomers of ZPC. Contradictory results in the literature, mainly related to plasma protein binding reported data, suggest that this is an unresolved matter and that more information is needed. Discrepancies and coincidences with previous data are highlighte…
Quattro studi sulla poesia d'amore mediolatina
2011
Il vol. presenta, debitamente ampliati, rielaborati e aggiornati, quattro studi (già precedentemente comparsi in varie sedi, dal 1993 al 2009) sulla poesia d’amore mediolatina, in un arco cronologico che va dal sec. VI (Venanzio Fortunato) al XIV (Giovanni del Virgilio e ser Nuccio da Tolentino), passando attraverso i secc. XI e XII (Ildeberto di Lavardin, il “contrasto” fra la monaca e il chierico). In genere, si tratta di un percorso fondato sull’analisi di testi particolarmente significativi (le poesie di Venanzio Fortunato, soprattutto quelle indirizzate a Radegonda di Turingia e ad Agnese di Poitiers; un carme di Ildeberto in lode della regina Matilde d’Inghilterra; il “contrasto” fra …
Water-insoluble β-cyclodextrin–epichlorohydrin polymers for removal of pollutants from aqueous solutions by sorption processes using batch studies: A…
2017
This review is dedicated to Giangiacomo Torri (Istituto di Chimica e Biochimica G. Ronzoni, Milan, Italy) in celebration of his retirement.; International audience; Although water-insoluble cyclodextrin-epichlorohydrin polymers have been known for half a century, these materials are of continued interest to the scientific community, in particular for their interesting environmental applications as sorbents in liquid-solid sorption processes. However, in spite of the abundance of literature and conclusive results obtained at the laboratory scale, interpreting the mechanisms of pollutant elimination remains an interesting source of debate and sometimes of contradiction. This review summarizes…
Supramolecular Assemblies Based on Complexes of Nonionic Amphiphilic Cyclodextrins and a meso-Tetra(4- sulfonatophenyl)porphine Tributyltin(IV) Deriv…
2013
Amphiphilic cyclodextrin (ACyD) provides water-soluble and adaptable nanovectors by modulating the balance between the hydrophobic and hydrophilic chains at both CyD sides. This work aimed to design nanoassemblies based on nonionic and hydrophilic ACyD (SC6OH) for the delivery of a poor-water-soluble organotin(IV)-porphyrin derivative [(Bu3Sn)4TPPS] to melanoma cancer cells. To characterize the porphyrin derivatives under simulated physiological conditions, a speciation was performed using complementary techniques. In aqueous solution (≤ 20 μM), (Bu3Sn)4TPPS primarily exists as a monomer (2 in Figure 1), as suggested by the low static anisotropy (ρ ≈ 0.02) with a negligible formation of por…
Pre- and post-modification of mixed cyclodextrin-calixarene co-polymers: A route towards tunability
2017
Various pre-modified and post-modified cyclodextrin-calixarene hyper-reticulated co-polymers were synthesized, fully characterized by different techniques (FT-IR, 13C{1H} CP-MAS and LGFS solid-state NMR, thermogravimetry, porosimetry), and tested to assess their absorption abilities as nanosponges. The construction of the polymer network was accomplished exploiting the well-known CuAAC reaction between two different heptakis-6-azido-β-cyclodextrins and two different propargyloxy-calix[4]arenes. Post-modification was aimed to achieve the presence of ionizable (acidic or basic) groups on the polymer framework. Sequestration tests towards two model pollutant molecules surprisingly showed that …
Temperature-controlled poly(propylene) glycol hydrophobicity on the formation of inclusion complexes with modified cyclodextrins. A DSC and ITC study.
2011
The study highlighted the main forces driving the formation of hydroxypropyl-cyclodextrins (HP-CDs) + poly(propylene) glycol 725 g mol(-1) inclusion complexes. The temperature parameter was chosen as the variable to modulate the hydrophobicity of the polymer, and consequently ITC experiments as functions of temperature as well as DSC measurements were done in a systematic way. The polymer is not included into HP-α-CD, it is strongly bound to HP-β-CD and it is floating in HP-γ-CD. The stability of the inclusion complexes is entropy controlled. The gain of the entropy is a unique result compared to the opposite literature findings for inclusion complexes based on polymers and CDs. This peculi…
Pore formation by Vibrio cholerae cytolysin requires cholesterol in both monolayers of the target membrane
2007
Vibrio cholerae cytolysin (VCC) forms oligomeric transmembrane pores in cholesterol-rich membranes. To better understand this process, we used planar bilayer membranes. In symmetric membranes, the rate of the channel formation by VCC has a superlinear dependency on the cholesterol membrane fraction. Thus, more than one cholesterol molecule can facilitate VCC-pore formation. In asymmetric membranes, the rate of pore formation is limited by the leaflet with the lower cholesterol content. Methyl-beta-cyclodextrin, which removes cholesterol from membranes, rapidly inhibits VCC pore formation, even when it is added to the side opposite that of VCC addition. The results suggest that cholesterol i…
Water Dynamics at the Solid-Liquid Interface to Unveil the Textural Features of Synthetic Nanosponges.
2020
A Fast-Field-Cycling NMR investigation was carried out on a set of polyurethane cyclodextrin nanosponges, in order to gain information on their textural properties, which have been proven to be quite difficult to assess by means of ordinary porosimetric techniques. Experiments were performed on both dry and wet samples, in order to evaluate the behavior of the “non-exchangeable” C-bound 1H nuclei, as well as the one of the mobile protons belonging to the skeletal hydroxyl groups and the water molecules. The results acquired for the wet samples accounted for the molecular mobility of water molecules within the channels of the nanosponge network, leading back to the possible pore size distrib…