Search results for "Anion"
showing 10 items of 488 documents
Micro magnetofluidics: droplet manipulation of double emulsions based on paramagnetic ionic liquids
2013
The ability to control and manipulate discrete fluid droplets by magnetic fields offers new opportunities in microfluidics. A surfactant-free and easy to realize technique for the continuous generation of double emulsion droplets, composed of an organic solvent and a paramagnetic ionic liquid, is applied. The inner phase of the emulsion droplet consists of imidazolium-based ionic liquids with either iron, manganese, nickel or dysprosium containing anions which provide paramagnetic behaviour. The double emulsion droplets are dispersed in a continuous phase of FC-40. All substances - the organic phase, the paramagnetic ionic liquid and the continuous phase -are immiscible. The magnetic proper…
Anionic Lipids Modulate the Activity of the Aquaglyceroporin GlpF
2015
AbstractThe structure and composition of a biological membrane can severely influence the activity of membrane-embedded proteins. Here, we show that the E. coli aquaglyceroporin GlpF has only little activity in lipid bilayers formed from native E. coli lipids. Thus, at first glance, GlpF appears to not be optimized for its natural membrane environment. In fact, we found that GlpF activity was severely affected by negatively charged lipids regardless of the exact chemical nature of the lipid headgroup, whereas GlpF was not sensitive to changes in the lateral membrane pressure. These observations illustrate a potential mechanism by which the activity of an α-helical membrane protein is modula…
New anionic cobalt complexes using highly hindered bis-amides with varying donor abilities as ligands.
2007
Four potential tetradentate ligands of formulae 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)ethane (H(4)L(1), 1), 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)propane (H(4)L(2), 2), 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)benzene (H(4)L(3), 3) and 1,8-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)naphthalene (H(4)L(4), 4) have been prepared and the crystal structures of three of them (1, 3 and 4) determined by single crystal X-ray diffraction. The investigation of their complexing ability toward Co(II) afforded the compounds of formulae [Co(III)(L(3))Na(I)(H(2)O)(2)] (5), [Co(III)(L(n))Li(I)(H(2)O)2] with n = 1 (6), 2 (7) and 3 (8) and [Co(II)(L(4))Li(I)(2)] (9). Complexes 5-8 are squa…
Detection of mitochondrial electron chain carrier redox status by transhepatic light intensity during rat liver reperfusion.
2003
The aim of the study was to investigate mitochondrial electron transfer during rat liver reperfusion after cold storage and hypothermic machine perfusion. Livers from male Brown Norway rats were preserved (UW) for 10h either by cold storage (CS) or by hypothermic oxygenated perfusion extracorporal (HOPE). Transhepatic photometric analysis allowed determination of the redox status of mitochondrial cytochromes during preservation, rewarming and reperfusion. Mitochondrial electron chain carriers were inhibited at different sites with rotenone and cyanide in some experiments. reversed transcriptional polymerase chain reaction (RT-PCR) was performed after reperfusion concerning transcription of …
Mitochondrial glutathione depletion by glutamine in growing tumor cells.
2000
The effect of L-glutamine (Gln) on mitochondrial glutathione (mtGSH) levels in tumor cells was studied in vivo in Ehrlich ascites tumor (EAT)-bearing mice. Tumor growth was similar in mice fed a Gln-enriched diet (GED; where 30% of the total dietary nitrogen was from Gln) or a nutritionally complete elemental diet (SD). As compared with non-tumor-bearing mice, tumor growth caused a decrease of blood Gln levels in mice fed an SD but not in those fed a GED. Tumor cells in mice fed a GED showed higher glutaminase and lower Gln synthetase activities than did cells isolated from mice fed an SD. Cytosolic glutamate concentration was 2-fold higher in tumor cells from mice fed a GED ( approximately…
Surface and Electronic Features of Fluorinated TiO 2 and Their Influence on the Photocatalytic Degradation of 1-Methylnaphthalene
2020
International audience; Surface fluorination improves the photocatalytic activity of TiO2, and the influences of various features of fluorinated TiO2 (TiO2–F) have often been discussed in the literature. The present paper addresses the changes induced by surface fluorination on the morphological, structural, surface, and electronic features of TiO2. In particular, X-ray diffraction, specific surface area analysis, and transmission and scanning electron microscopy give evidence that surface fluorination does not affect the structural properties and the morphology of TiO2 nanoparticles. In contrast, fluorination induces changes of surface and electronic properties. Chemical and thermogravimet…
Dynamic magnetic materials based on the cationic coordination polymer [Cu(btix)2]n(2n+) [btix = 1,4-bis(triazol-1-ylmethyl)benzene]: tuning the struc…
2012
A three-dimensional coordination polymer, [Cu(btix)(2)(BF(4))(2)](n) [btix = 1,4-bis(triazol-1-ylmethyl)benzene], with antiferromagnetic interactions occurring via the organic ligand, has been prepared and characterized. It has been shown to permit the exchange of anionic species in the crystalline network with modification of the magnetic properties. Coordinated BF(4)(-) can be reversibly exchanged by different anions with (NO(3)(-) and Cl(-)) or without (PF(6)(-) and ClO(4)(-)) dynamic response of the organic ligand, which acts as the only linker between the metal centers. Interestingly, an irreversible exchange occurs with N(3)(-) anions to generate a new coordination polymer, [Cu(btix)(…
Polyfunctional recognition of pyridinedicarboxylate anions with macrocyclic polyamine receptors containing heteroaromatic groups.
2008
The interaction of the biologically relevant anions deriving from the six pyridinedicarboxylic acids (H2PDC) with two macrocyclic receptors containing a pentamine chain and a bipyridine (1) or a phenanthroline (2) moiety, as well as with the aliphatic analogue [21]aneN7 (3), was studied by means of spectroscopic methods (UV-vis, NMR) and potentiometric titrations affording the stability constants of the adducts formed. All three receptors form stable complexes with the substrates thanks to the formation of several salt bridges and hydrogen bond contacts, as observed in the crystal structure of the H8[3(2,6-PDC)4] x H2O x 0.5 EtOH solid compound. Additional pi-stacking interactions between t…
A highly enantioselective abiotic receptor for malate dianion in aqueous solution
2006
The highly enantioselective molecular recognition of the malate dianion by a synthetic receptor in aqueous solution has been studied by potentiometric titrations, mass spectrometry (ESI-MS), diffusion measurements (PGSE NMR) and molecular modeling. Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es
[3.3]Ferrocenophanes with guanidine bridging units as multisignalling receptor molecules for selective recognition of anions, cations, and amino acid…
2007
The synthesis, electrochemical, and optical properties of a new [3.3]ferrocenophane framework in which two ferrocene subunits, with similar electronic environments, are linked through two substituted guanidine moieties, are reported. The receptors 4-7 have been prepared in good yields by the reaction of bis(carbodiimide) 3 with primary amines. This architecture is exceptionally "tunable" because a variety of "legs" may be appended to the basic [3.3]ferrocenophane scaffold to give a wide range of signaling units. These receptors show remarkable ion-sensing properties, due to the presence of a redox active unit (ferrocene), and an amphoteric binding site (guanidine). In this nitrogen-rich str…