Search results for "strength"
showing 10 items of 2415 documents
Complexes of Azelaic and Diethylenetrioxydiacetic Acids with Na+, Mg2+, and Ca2+ in NaCl Aqueous Solutions, at 25 °C
1999
Formation constants of Na + , Mg 2+ , and Ca 2+ complexes of azelaic and diethylenetrioxydiacetic acids have been determined by potentiometry (H + -glass electrode) at different ionic strengths (0 ≤ I ≤ 1 mol dm -3 ), at t = 25 °C. For all the systems the species ML and MHL have been found. The relative formation constants are reported together with the parameters for the dependence on ionic strength. Results are discussed in comparison with those for other carboxylic ligands. Speciation problems are considered also.
Cell adhesion molecule in the hexactinellid Aphrocallistes vastus
1984
Abstract The Hexactinellida sponge Aphrocallistes vastus contains a soluble aggregation factor (AF) whose purification has been described in this communication. It is characterized by a S° 20.w value of 37 and a buoyant density of 1.45 g/cm 3 . The AF is a glycoporteinaceous particle composed of three major protein species; no core structure could be visualized. In the presence of Ca 2+ , the AF causes secondary aggregation of single cells. The aggregation process is temperature, pH, and ionic strength independent within a broad range. Evidence is presented indicating that two (or more) AF molecules are required for the establishment of a stable cell: cell interaction. In contrast to the AF…
High performance PA6/CNTs nanohybrid fibers prepared in the melt
2012
Commercial and home-made carbon nanotubes (CNTs) were plasma treated under oxygen atmosphere and then added to polyamide 6 (PA6) in order to prepare fibres by melt spinning. For comparison, pristine nanofillers were used too. The effect of functionalization and of filler characteristics on the morphological, rheological, mechanical and electrical properties of the fibres was studied by TEM and SEM, rheological measurements, tensile and electrical conductivity tests. The results demonstrated that the functionalization led to a better mechanical performance and the morphological analysis confirmed that the adhesion, the dispersion and the alignment of the nanotubes within the polymer matrix w…
Modelling of natural synthetic polyelectrolyte interactions in natural waters by using SIT, Pitzer and Ion Pairing approaches
2006
Abstract In this paper SIT and Pitzer models are used for the first time to describe the interactions of natural and synthetic polyelectrolytes in natural waters. Measurements were made potentiometrically at 25 °C in single electrolyte media, such as Et 4 NI and NaCl (for fulvic acid 0.1 − 1 S single salt ” BA, with cation B and anion A representing all the major cations (Na + , K + , Mg 2+ , Ca 2+ ) and anions (Cl − , SO 4 2− ) in natural sea water, respectively. The ion pair formation model was also applied to fulvate and alginate in artificial sea water by examining the interaction of polyanions with the single sea water cation. Results were compared with those obtained from previous sp…
Solution properties of polyelectrolytes
1991
Abstract Chromatographic data for sodium polystyrene sulphonate were obtained on both silica- and polymer-based size-exclusion supports using mobile phases of various pH and ionic strength. Deviations of the elution volume were observed towards both lower and higher values relative to the reference calibration graph obtained with uncharged standards. An empirical correlation is proposed in order to account for all the secondary effects observed. The general applicability of this correlation was further tested for chromatographic data obtained for a series of peptides and proteins on a silica-based support under very different eluent conditions. Deviations from ideal elution behaviour such a…
Chiral separation of ephedrines by liquid chromatography using β-cyclodextrins
2001
β-cyclodextrins (β-CDs) have been evaluated as chiral recognition agents for the enantioseparation of ephedrines by liquid chromatography (LC). The compounds tested were norephedrine, ephedrine, pseudoephedrine, N-methylephedrine and N-methylpseuoephedrine. Two possibilities have been investigated, the employment of a chiral stationary phase consisting of immobilized β-cyclodextrin, and the addition of the chiral selector to the mobile phase. In the latter approach the following chiral agents have been assayed, native β-cyclodextrin (β-CD), methyl-β-cyclodextrin (M-β-CD), carboxyethyl-β-cyclodextrin (CE-β-CD), carboxymethyl-β-cyclodextrin (CM-β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD)…
Isolation From Human Calcium Oxalate Renal Stones of Nephrocalcin, a Glycoprotein Inhibitor of Calcium Oxalate Crystal Growth. Evidence That Nephroca…
1987
We have determined that the organic matrix of calcium oxalate kidney stones contains a glycoprotein inhibitor ofcalcium oxalate crystal growth (nephrocalcin) that resembles nephrocalcin present in the urine of patients with calcium oxalate stones and differs from nephrocalcin from the urine of normal people. Pulverized calcium oxalate renal stones were extracted with 0.05M EDTA, pH 8.0; nephrocalcin eluted in five peaks using DEAE-cellulose column chromatography, and each peak was further resolved by Sephacryl S-200 column chromatography. Four ofthe fiveDEAE peaks corresponded to those usually found in nephrocalcin from urine; the fifth eluted at a lower ionic strength than any found in uri…
Mechanical Behavior of Concrete Columns Confined by Laterally Pre-Tensioned FRP
2011
This paper presents the results of an experimental investigation of concrete columns confined by a wound pre-tensioned carbon filament yarn. Yarn winding equipment was developed in the Institute of Polymer Mechanics with the ability to set the desired pre-tension force and thereby producing confined concrete specimens with different initial lateral pressure. It is shown that initial lateral pressure increases the axial stress at which intense internal cracking of the concrete develops.
Development of competitive enzyme-linked immunosorbent assays for boscalid determination in fruit juices
2012
Abstract Boscalid is a modern, broad-spectrum carboxamide pesticide highly efficient against most fungal diseases affecting valuable crops. In this study, a boscalid-mimicking derivative with a six-carbon spacer arm replacing the chlorine atom at the pyridine ring of the target molecule was synthesized and coupled to carrier proteins. Following rabbit immunization, antibodies against this agrochemical were obtained for the first time, and they were characterised in terms of affinity and specificity, tolerance to solvents, and robustness to changes in buffer pH and ionic strength, using two assay formats. Both of the optimised immunoassays showed limits of detection below 0.1 μg/L. Moreover,…