Search results for "electrolytes"
showing 10 items of 84 documents
Sequestration of biogenic amines by alginic and fulvic acids.
2006
The interaction of natural (alginic and fulvic acids) and synthetic (polyacrylic acid 2.0 kDa) polyelectrolytes with some protonated polyamines [diamines: ethylendiamine, 1,4-diaminobutane (or putrescine), 1,5-diaminopentane (or cadaverine); triamines: N-(3-aminopropyl)-1,4diaminobutane (or spermidine), diethylenetriamine; tetramine: N.N'-bis(3-aminopropyl)-1,4-diaminobutane (or spermine); pentamine: tetraethylene-pentamine; hexamine: pentaethylenehexamine] was studied at T=25 degrees C by potentiometry and calorimetry. Measurements were performed without supporting electrolyte, in order to avoid interference, and results were reported at I=0 mol L(-1). For all the systems, the formation of…
Blocking of an ion channel by a highly charged drug: Modeling the effects of applied voltage, electrolyte concentration, and drug concentration
2005
We present a simple physical model to estimate the blocked pore probability of an ion channel that can be blocked by a highly charged drug in solution. The model is inspired by recent experimental work on the blocking of the ${\mathrm{PA}}_{63}$ channel, involved in the anthrax toxin infection, by a highly charged drug [Karginov et al. PNAS 102, 15075 (2005)]. The drug binding to the pore is highly specific but the strong dependence of blocking on the applied voltage and electrolyte concentration suggests that long range electrostatic interactions are important. Since basic electrostatic concepts rather than detailed molecular models are considered, the microscopic details of the channel bl…
Tetraurea calix[4]arenes with sulfur functions: synthesis, dimerization to capsules, and self-assembly on gold.
2007
Various calix[4]arene derivatives, fixed in the cone conformation by decylether groups and functionalized at their wide rim by urea residues, were synthesized. In two compounds (4f,g) sulfur functions were attached to the urea groups via different spacers in order to allow binding to metal surfaces. While they exist as single molecules in polar solvents, tetraurea calix[4]arenes of this type (4) combine to form dimeric capsules in aprotic, apolar solvents. A solvent molecule is usually included in such a capsule, if no guest with a higher affinity is present. In the presence of an equimolar amount of the tetratosylurea 5, the exclusive formation of heterodimers, consisting of one molecule o…
1712 Serum Electrolytes Variations in Treated Patients with Moderate Asthma Exacerbation
2012
Background Salbutamol induces stimulation of beta 2 -receptors resulting in hypokalemia. Corticosteroids also induce plasma electrolytes variations. Aims To identify blood electrolytes changes following low dose inhaled short-acting beta 2 -agonists; To evaluate if concomitant inhaled corticosteroids treatment can amplify serum electrolytes changes. Methods We analyzed all children admitted for moderate asthma exacerbation during 6 months period. Inclusion criteria: children between 5–18 years of age; PEF >50–75% of predicted value; serum electrolytes normal ranges. Exclusion criteria: previously treated patients with Salbutamol; Salbutamol hypersensitivity; asthma exacerbation severity lev…
Improvements in Rational Design Strategies of Inulin Derivative Polycation for siRNA Delivery.
2016
The advances of short interfering RNA (siRNA)-mediated therapy provide a powerful option for the treatment of many diseases, including cancer, by silencing the expression of targeted genes involved in the progression of the pathology. On this regard, a new pH-responsive polycation derived from inulin, Inulin-g-imidazole-g-diethylenetriamine (INU-IMI-DETA), was designed and employed to produce INU-IMI-DETA/siRNA "Inulin COmplex Nanoaggregates" (ICONs). The experimental results showed that INU-IMI-DETA exhibited strong cationic characteristics and high solubility in the pH range 3-5 and self-aggregation triggered by pH increase and physiological salt concentration. INU-IMI-DETA showed as well…
Segmental dynamics in polymer electrolytes
2002
Polymer dynamics in poly(ethylene oxide) (PEO)–salt mixtures is investigated by means of quasi-elastic neutron scattering (QENS). In a previous study, we reported QENS data from the NEAT spectrometer (BENSC) that evidenced, for the first time, a dynamic heterogeneity in PEO–salt mixtures induced by salt addition. This finding is supported by molecular dynamics (MD) simulations carried out by Borodin et al. In agreement with MD simulations, our QENS data revealed two distinct processes: a fast motion corresponding to the bulk polymer and a slower relaxation, which we attribute to formation of PEO–cation complexes. In this paper we present new QENS data from the high-resolution spectrometer I…
Electrosynthesis of Ce–Co Mixed Oxide Nanotubes with High Aspect Ratio and Tunable Composition
2008
Cerium oxide and cobalt oxides have attracted the interest of several researchers due to their potential application in several technological fields electrochromism, lithium batteries, catalysis, etc.. Ceria has been used as a promoter in the so-called “three-way catalyst” for the control of toxic emission from automobile exhaust. The promotion consists of the enhancement of the noble metal dispersion, as well as stabilization of the supporting medium toward thermal sintering. 1,2 A direct catalytic effect of CeO2 in chemical processes such as water–gas shift reaction or NOx decomposition has been also evidenced. 3,4
Defect interaction and local structural distortions in Mg-doped LaGaO3: A combined experimental and theoretical study
2017
A combined experimental and theoretical study of Mg-doped LaGaO3 electrolyte was carried out, with the aim to unveil the interaction between oxygen vacancy (Vo) and perovskite B site cations. LaGaO3 (LG) and LaGa0.875Mg0.125O2.938 (LGM0125) samples were comprehensively characterized by X-ray absorption spectroscopy (XAS) and X-ray diffraction, in order to investigate short- and long-range structures of both undoped and Mg-doped materials. XAS analysis evidenced a preferential Ga-Vo interaction in LGM0125, confirmed by periodic hybrid density functional theory calculations, which were combined with a symmetry-independent classes (SICs) approach in order to (a) obtain a detailed picture of th…
Morphology of solid polymer electrolytes: a TR WAXS investigation
2002
A wide angle X-ray scattering investigation of (polyethylene oxide)n–sodium thiocyanate [(PEO)nNaSCN] mixtures is reported. Temperature dependence analysis for different mixtures is shown, in order to rationalize the multi-phase behaviour. Depending on the amount of salt added and upon the temperature considered three different phases have been found to simultaneously coexist: crystalline PEO, amorphous PEO, and crystalline complex.
Selective Inhibition of Human Natural Killing and Antibody-Dependent Cellular Cytotoxicity by a Polyanion
1987
A high molecular polyanion, Liquoid, was found to inhibit at nontoxic concentrations (12-50 micrograms/ml) the natural killing (NK) and the antibody-dependent cellular cytotoxic (ADCC) activity of human peripheral blood mononuclear cells selectively. Whereas NK of the K 562 target cell was slightly or not at all affected, the spontaneous lysis of PDe-B-1, an EBV-transformed B-cell line, was strongly inhibited or even completely abolished. ADCC activity could only be inhibited by Liquoid if the target cells were mycoplasma-free, while the polyanion had no effect when mycoplasma-contaminated target cells were used. Liquoid did not alter the target binding capacity of the NK effector cells and…