Amphiphilic 2,6-pyridylene ethynylene "meta-ethynylpyridine" polymers having chiral oligo(oxyethylene) side chains were developed as hosts for saccharide recognition. The polymers were prepared via a Sonogashira reaction and fractionated by gel permeation chromatography (GPC). They showed circular dichroism (CD) activity due to their higher-order chiral helical structures, and their CD and UV-v...

In this study, the efficiency of a clean-up method by gel permeation chromatography (GPC) for the separation of pesticides from lanolin is analyzed. The pesticides analyzed belong to two different families, organophosphorous and synthetic pyrethroids. Lanolin, a standard mixture of the pesticides, and a lanolin-pesticides mixture are injected in a GPC column. The recoveries and elution times fr...

One-day-old leghorn chickens were used in a laboratory assay to determine the toxicity of crude extracts of the tick Argas (Persicargas) walkerae and of fractions obtained during the isolation procedure. Extracts of unfed and engorged larvae, nymphae and females were tested using this in vivo test system. Only extracts of replete A. (P.) walkerae larvae produced paralysis. A toxic fraction was ...

486 Use of low-angle laser light scattering with gel permeation chromatography for the molecular mass determination of biomolecules K. Jumel,* P. Br0wne.t and J. F. Kennedy# *Chembiotech Ltd, Institute of Research and Development, Vincent Drive, Edgbaston, Birmingham B I5 2sQ, U.K.; tLDC Analytical, Diamond Way, Stone Business Park, Stone, Staffs STI 5 OHH, U.K. and $Research Laboratory for the...

Presence of atrial natriuretic factor (ANF)-like material was demonstrated by radioimmunoassay in ascitic fluid of 14 patients with cirrhosis of the liver. Immunoreactive ANF concentrations (M +/- SEM) were 2.4 +/- 0.5 fmol/ml in ascites, significantly lower (p less than 0.001) than the corresponding plasma concentrations of 15.5 +/- 2.6 fmol/ml. High performance gel permeation chromatography a...

A putative capsular polysaccharide containing D-rhamnose was isolated from the phytopathogenic bacterium Burkholderia gladioli pv. agaricicola by phenol/water extraction followed by ultracentrifugation of the separated water phase and gel-permeation chromatography of the thus obtained supernatant. By means of chemical analyses and NMR spectroscopy, the repeating unit of the polymer was shown to...

This paper describes an accelerated ageing experiment of transformer oil/paper insulation with preset moisture levels. These samples were tested with return voltage and polarisation/depolarisation measurements. Molecular weight has also been measured with Gel Permeation Chromatography (GPC). Results suggested the impact of moisture on the ageing of oil/paper insulation. An attempt has been made...

Two isoforms of acidic 1,2-a-D-mannosidases have been isolated from culture filtrate of Penicillium citrinum. The pl values of the two forms, designated 1,2-a-mannosidase la and lb, were 4.6 and 4.7 respectively. Isoenzymes Ia and Ib exhibited the same molecular mass which was determined to be 53 kDa by SDS/ PAGE and 54 kDa by gel-permeation chromatography. Enzymes Ia and lb hydrolysed yeast ma...

Biodegradable four-arm star-shaped poly(lactic acid) (4sPLA) was synthesized from l-Lactic acid (l-LA) and pentaerythritol (PENTA), the polymerization kinetics studied. The effects of reaction time, temperature molar ratio on 4sPLA were discussed. molecular structure characterized by Fourier transform infrared spectroscopy (FTIR) 1H nuclear magnetic resonance spectra (1H-NMR). results showed th...

In this work, the thermo-oxidative behavior of PEKK films (~50 µm thick) in solid state were investigated. Since mechanical properties samples, especially strain at break, are clearly affected after long ageing time, modifications structure have been monitored molecular and macromolecular scales using different techniques such as gel permeation chromatography, X-Ray scattering, differential sca...