Search results for "Electrolyte"
showing 10 items of 746 documents
Radiochemical separation of no-carrier-added as produced via the process
2000
The 176Yb(n,gamma)177Yb-beta(-)-->177Lu process was investigated to provide no-carrier-added (nca) 177Lu. The radiochemical separation of the 177Lu from the macro-amounts of the ytterbium target based on the cementation process, i.e. the selective extraction of Yb by Na(Hg) amalgam from Cl-/CH3COO- electrolytes, followed by a final cation exchange purification. The cementation separation process provides a decontamination factor of Yb(III) of 10(4), the cation exchange purification adding a decontamination factor of > 10(2). The nca 177Lu is available in radiochemically pure form despite the chemical similarity of the lanthanides with 75 +/- 5% overall separation yield within 4-5 h. It can …
Proof of multilayer structural organization in self-assembled polycation-polyanion molecular films
1994
Abstract Multilayer organization of ultrathin polycation-polyanion self-assembled films is demonstrated using two approaches. (1) Fabrication of polyion superlattices with alternation of three different polyelectrolytes in (ABCB) n fashion, which gives rise to a Bragg peak in X-ray reflectivity. The spacing d=93.4 A corresponds to the repeat unit (ABCB) n . (2) Drying-induced manipulation of the film surface at regular intervals. Normally the layer-by-layer adsorption is carried out by keeping the film wet throughout all deposition cycles. Alternatively the film surface can be manipulated by gently drying the film in a stream of nitrogen or air after the adsorption of every layer. When the …
Macromolecules in ordered media VIII. High-performance size-exclusion chromatography as a technique for characterizing the interaction between polyan…
1997
Abstract The association of polyanions with liposomes based on dimyristoyl phosphatidyl choline and stearylamine at a ratio of 50:50 was investigated in terms of the binding model and, to a lesser extent, of the partition model. Aqueous size-exclusion chromatography has been proposed as a major technique for monitoring the interactions between liposomes and polyelectrolytes and the results were compared with those obtained by fluorescence spectroscopy. Quantitatively, the extent of the association follows the order: Sodium poly(styrene sulfonate) ( K A = 10 000 M −1 ), poly (acrylic acid) ( K A = 2000 M −1 ) and poly ( l -glutamic acid) ( K A = 700 M −1 ). Also, the effect of the ionic stre…
Macromolecules in ordered media. 6. Effect of the phospholipidic bilayer composition on poly (2-vinyl pyridine) - liposome association
1997
The intrinsic fluorescence emission of poly (2-vinyl pyridine) has been exploited in order to gain insight into the nature of the interaction with artificial membranes. In this contribution, the study has been focused on the effect of the phospholipid bilayer composition on the association to the polymer. Fluorescence data have been converted into association isotherms and then analyzed in terms of both binding and partition models. Results show that the association is enhanced by the presence of negative charged phospholipid as a constituent of the liposomal membrane. The strong surface density dependence of the polymer-liposome association indicatesthe predominantly electrostatic nature o…
Macromolecules in ordered media: 7. Influence of ionic strength and bilayer composition on the association of polyelectrolytes to mixed liposomes
1997
The effect of both the phospholipid composition of the bilayer and the ionic strength of the medium on the association between poly(2-vinyl pyridine) and mixed liposomes based on dimyristoyl phosphatidic acid and dimyristoyl phosphatidil choline was investigated using fluorescence spectroscopy. Intensity changes upon addition of vesicles have allowed us to estimate the extent of the association and data have been processed as association isotherms. We found that the association is enhanced by increasing both the ionic strength and the anionic phospholipid fraction. However, whereas the negative net charge of the bilayer strongly enhances the interaction, the presence of more and more electr…
Logic Functions with Stimuli-Responsive Single Nanopores
2014
[EN] We present the concept of logic functions based on a single stimuli-responsive nanopore and analyze its potential for electrochemical transducers and actuators. The responsive molecules at the surface of the polymeric nanopore immersed in an electrolyte solution are sensitive to thermal, chemical, electrical, and optical stimuli, which are the input signals required to externally tune the conductance of the nanopore (the logical output). A single nanostructure can be operated as a resistor or as a diode with a broad range of rectifying properties, allowing for logical information-processing schemes that are useful pH and temperature sensors, electro-optical detectors, and electrochemic…
Evolution of osmosensing signal transduction in Metazoa: stress-activated protein kinases p38 and JNK.
2001
Sponges (Porifera) represent the most basal branch of the Metazoa alive today. We show that two central stress-activated protein kinases involved in the osmosensing pathway, p38 mitogen-activated protein kinase (MAPK) and JNK, can complement for the ancestral MAPK Hog1 in the yeast Saccharomyces cerevisiae. S. cerevisiae mutants lacking Hog1 (hog1-Delta 1) have been complemented with the sponge SDJNK and SDp38 genes. Western blotting has revealed that, after transformation, the hog1-Delta 1+ SDJNK(sense) and hog1-Delta 1+ SDp38(sense) clones express the sponge proteins. Functional studies have demonstrated that the complemented clones grow under hyperosmotic conditions (0.6 M NaCl). Further…
Corporeal Compression at the Onset of Septic shock (COCOONs): a compression method to reduce fluid balance of septic shock patients
2019
AbstractFluid overload in septic intensive care unit (ICU) patients is common and strongly associated with poor outcome. There is currently no treatment for capillary leak, which is mainly responsible for high positive fluid balance (FB) in sepsis. We hypothesized that increasing interstitial pressure with extensive corporeal compression would reduce FB. The objective of this study was to evaluate the feasibility, efficacy, and safety of a compression treatment during sepsis. This pilot, two-center, single-arm trial enrolled critically ill, non-surgical, septic patients receiving mechanical ventilation. The therapeutic intervention was the early application of compression bandages on more t…
Mechanistic basis for unexpected bioavailability enhancement of polyelectrolyte complexes incorporating BCS class III drugs and carrageenans
2013
The objective of this study was to investigate the potential of λ-carrageenan to work as an absorption modifying excipient in combination with formulations of BCS class 3 substances. Trospium chloride was used as a model BCS class 3 substance. Polyelectrolyte complexes of trospium and λ-carrageenan were produced by layer-by-layer complexation. A λ-carrageenan-containing formulation was administered either in capsules size 9 to rats by gavage or directly into ligated intestinal loops of rats. Exceptionally strong variations were observed in the plasma concentrations of the rats that received λ-carrageenan compared to the control group, but enhanced plasma concentrations were observed only in…
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…