Search results for "amine"
showing 10 items of 7299 documents
Ion–Molecule Rate Constants for Reactions of Sulfuric Acid with Acetate and Nitrate Ions
2022
Atmospheric nucleation from precursor gases is a significant source of cloud condensation nuclei in the troposphere and thus can affect the Earth's radiative balance. Sulfuric acid, ammonia, and amines have been identified as key nucleation precursors in the atmosphere. Studies have also shown that atmospheric ions can react with sulfuric acid to form stable clusters in a process referred to as ion-induced nucleation (IIN). IIN follows similar reaction pathways as chemical ionization, which is used to detect and measure nucleation precursors via atmospheric pressure chemical ionization mass spectrometers. The rate at which ions form clusters depends on the ion-molecule rate constant. Howeve…
Metabolic signatures across the full spectrum of non-alcoholic fatty liver disease.
2022
Funder: European Commission
Ferromagnetic coupled μ-phenoxo-μ-carboxylato heterodinuclear complexes based on the Cr(salen) moiety: Structural and magnetic characterization
2009
The synthesis, crystal structure, and magneto-chemical characterization of two new unprecedented μ-phenoxo-μ-carboxylato heterodinuclear complexes based on the Cr(salen) moiety (salen = N,N′-bis(salicylidene)ethylenediamine), [MII(O2C(CH3)3)(OH2)2(μ-O2C(CH3)3)(μ-salen)CrIII(O2C(CH3)3)], M = Ni (2), Co(3) are reported. The dinuclear complexes were obtained starting from the mononuclear trans-[Cr(salen)(CN)2]PPh4 (1), whose crystal structure is also reported. They show a trans arrangement of the Cr(salen) unit, bridging through the phenolate O atoms to a second metal center. An additional μ2-O2-carboxylato bridge and a further monodentating carboxylate ligand complete the roughly octahedral C…
Stabilized Naked Sub-nanometric Cu Clusters within a Polymeric Film Catalyze C-N, C-C, C-O, C-S, and C-P Bond-Forming Reactions
2015
[EN] Sub-nanometric Cu clusters formed by endogenous reduction of Cu salts and Cu nanoparticles are active and selective catalysts for C−N, C−C, C−O, C−S, and C−P bond-forming reactions. Sub-nanometric Cu clusters have also been generated within a polymeric film and stored with full stability for months. In this way, they are ready to be used on demand and maintain high activity (TONs up to 104 ) and selectivity for the above reactions. A potential mechanism for the formation of the sub-nanometric clusters and their electronic nature is presented.
Selective downregulation of the MDR1 gene product in Caco-2 cells by stable transfection to prove its relevance in secretory drug transport.
2005
Considerable interest is focused on overcoming multidrug resistance (MDR) in cancer chemotherapy. The in vitro experiments to characterize P-glycoprotein's (P-gp) function and to decrease its effects have led to a variety of strategies such as addition of competitors or supplementation of the medium with oligonucleotides complementary to the 5'-end of the MDR1-mRNA. For the Caco-2 cell line, an in vitro model for absorption screening, expressing multiple transporters including P-gp, which pumps substances back into the apical solution, P-gp activity might mask other relevant transport proteins' activity. The objective of the present study was to construct a Caco-2 subline with reduced P-gp …
Synthesis, structural diversity, inter-conversion and reactivity of Cu(II) complexes of hydroxy-rich molecules
2002
Tetranuclear Cu(II) complexes having linear, cubane and pseudodouble-cubane cores were synthesized using hydroxy-rich molecules possessing amine and imine groups. The products were structurally characterized and were studied for their ability to oxidize catechol as well as for their inter-conversion between mono- and tetra-nuclear complexes.
Recognition of oxovanadium(V) species and its separation from other metal species through selective complexation by some acyclic ligands
1998
Acyclic molecules possessing –OH (phenoxo and alkoxo type) groups and imine or amine moieties have been developed to sense the specific preference for VO3+ species. These molecules also showed a capability to quantitatively separate oxovanadium(V) species from a reaction mixture containing metal species of V, Mo, U, Fe, and Mn ions in solution. A cascade quantitative separation of VO3+ followed by cis–MoO2+2 followed by trans –UO2+2 species is demonstrated from their mixture. Synthesis and structural details of oxo-species of vanadium molybdenum and uranium are also discussed. Factors influencing the complexation of these molecules towards oxo metal species of V, Mo and U are also addressed.
Synthesis of polymeric derivatives of isoniazid: characterization and in vitro release from a water-soluble adduct with polysuccinimide.
1989
Coupling of isoniazid with polysuccinimide afforded a water-insoluble polymeric pro-drug; by reaction with ethanolamine it was chemically transformed in a water-soluble adduct. The in vitro release of isoniazid from the drug-polymer adduct was studied by using an artificial stomach wall lipid membrane. The transfer rate constant from simulated gastric juice to simulated plasma was defined and compared with that of an equivalent dose of pure drug.
DNA-binding of zinc(II) and nickel(II) salphen-like complexes extrapolated at 1 M salt concentration: Removing the ionic strength bias in physiologic…
2020
Abstract The DNA-binding of two salphen-like metal complexes of nickel(II) (1) and zinc(II) (2) was investigated in different ionic strength solutions by absorption spectroscopy. The data analysis allowed us to obtain the values of their extrapolated DNA-binding constant in physiological conditions, with DNA-binding strength in the order Ni > Zn, and to give relative weight to the electrostatic and non-electrostatic contributions to their DNA-interaction.
Between Interactions and Aggregates: The PolyQ Balance
2021
Abstract Polyglutamine regions (polyQ) are highly abundant consecutive runs of glutamine residues. They have been generally studied in relation to the so-called polyQ-associated diseases, characterized by protein aggregation caused by the expansion of the polyglutamine tract via a CAG-slippage mechanism. However, more than 4800 human proteins contain a polyQ, and only 9 of these regions are known to be associated with disease. Computational sequence studies and experimental structure determinations are completing a more interesting picture in which polyQ emerge as a motif for modulation of protein-protein interactions. But long polyQ regions may lead to an excess of interactions, and produc…