Polymer degradation mechanism and chemical composition relationship of hot-poured asphaltic crack repair material during thermal aging exploiting fluorescence microscopy and gel permeation chromatography

2021 ◽  
Vol 302 ◽  
pp. 124412
Author(s):  
Chen Yang ◽  
Yu Lu ◽  
Liping Cao ◽  
Zhiyang Liu ◽  
Tiantao Zhang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Fluorescence Microscopy ◽  
Thermal Aging ◽  
Degradation Mechanism ◽  
Polymer Degradation ◽  
Gel Permeation Chromatography ◽  
Repair Material ◽  
Gel Permeation ◽  
Crack Repair ◽  
Relationship Of

Chemical composition of lipopolysaccharide from an avian strain of Escherichia coli O18

1970 ◽  
Vol 16 (11) ◽  
pp. 1117-1121
Author(s):  
J. Lopes ◽  
W. E. Inniss
Keyword(s):  
Escherichia Coli ◽  
Chemical Composition ◽  
Gel Permeation Chromatography ◽  
Gel Permeation ◽  
Phenol Water ◽  
Avian Strain

Lipopolysaccharide (LPS) was isolated from an avian strain of Escherichia coli O18 by extraction of the cells with NaCl followed by treatment with phenol–water, methanol precipitation, and gel permeation chromatography. The LPS consisted of carbohydrate, lipid, and a small amount of protein and phosphate. Further analysis showed the presence of glucose, galactose, rhamnose, glucosamine, N-acetylglucosamine, heptose, 2-keto-3-deoxyoctonate (KDO), and ethanolamine. The composition of the LPS is qualitatively similar to that found for LPS obtained from various other bacteria.

SOMATOSTATIN IMMUNOREACTIVE PEPTIDES OF HIGHER MOLECULAR WEIGHT IN OVINE HYPOTHALAMIC EXTRACTS

1978 ◽  
Vol 77 (3) ◽  
pp. 429-430 ◽  
Author(s):  
R. P. MILLAR
Keyword(s):  
South Africa ◽  
Molecular Weight ◽  
Medical School ◽  
Gel Permeation Chromatography ◽  
Research Unit ◽  
Rat Pancreas ◽  
Gel Permeation ◽  
Protein Research ◽  
Somatostatin Immunoreactivity ◽  
Relationship Of

U.C.T./M.R.C. Protein Research Unit, Department of Chemical Pathology, Medical School, Observatory 7925, Cape Town, Republic of South Africa (Received 26 January 1978) Higher molecular weight (HMW) immunoreactive forms of somatostatin have been reported in extracts of ovine hypothalami (Vale, Ling, Rivier, Villarreal, Rivier, Douglas & Brown, 1976), rat pancreas and stomach (Arimura, Sato, Dupont, Nishi & Schally, 1975) and human pancreatic somatostatinoma (Larsson, Hirsch, Holst, Ingemansson, Kühl, Jensen, Lundquist & Rehfeld, 1977). However, the possibility that the HMW immunoreactive substances were oligomers of somatostatin or somatostatin bound to larger molecules was not excluded. The present study was undertaken to establish that authentic HMW immunoreactive somatostatin is present in the ovine hypothalamus and to glean information on the structural relationship of the HMW species with somatostatin. Sheep hypothalami were extracted and subjected to gel permeation chromatography as described previously by Millar, Aehnelt & Rossier (1977). Fractions were assayed for somatostatin immunoreactivity

Aggregated, Conformationally Changed Fibrinogen Exposes the Stimulating Sites for t-PA-Catalysed Plasminogen Activation

1996 ◽  
Vol 75 (02) ◽  
pp. 326-331 ◽  
Author(s):  
Unni Haddeland ◽  
Knut Sletten ◽  
Anne Bennick ◽  
Willem Nieuwenhuizen ◽  
Frank Brosstad
Keyword(s):  
Conformational Changes ◽  
Gel Permeation Chromatography ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Chromogenic Substrate ◽  
Type Plasminogen Activator ◽  
Gel Permeation ◽  
Self Association ◽  
Fibrin Monomers ◽  
Stimulation Of

SummaryThe present paper shows that conformationally changed fibrinogen can expose the sites Aα-(148-160) and γ-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs directed to these sites, and was shown to coincide with stimulation of t-PA-catalysed plasminogen activation as assessed in an assay using a chromogenic substrate for plasmin. Gel permeation chromatography of fibrinogen conformationally changed by heat (46.5° C for 25 min) demonstrated the presence of both aggregated and monomeric fibrinogen. The aggregated fibrinogen, but not the monomeric fibrinogen, had exposed the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation. Fibrinogen subjected to heat in the presence of 3 mM of the tetrapeptide GPRP neither aggregates nor exposes the rate-enhancing sites. Thus, aggregation and exposure of t-PA-stimulating sites in fibrinogen seem to be related phenomena, and it is tempting to believe that the exposure of stimulating sites is a consequence of the conformational changes that occur during aggregation, or self-association. Fibrin monomers kept in a monomeric state by a final GPRP concentration of 3 mM do not expose the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation, whereas dilution of GPRP to a concentration that is no longer anti-polymerizing, results in exposure of these sites. Consequently, the exposure of t-PA-stimulating sites in fibrin as well is due to the conformational changes that occur during selfassociation.

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