Surface Tension as a Function of Molecular Weight of Protonated Free and Conjugated Dihydroxy Bile Acids

1986 ◽  
Vol 71 (s15) ◽  
pp. 72P-72P
Author(s):  
C O Mills ◽  
G H Martin ◽  
E Elias
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Bile Acids

scholarly journals Average molecular weight of surfactants in aerosols

2007 ◽  
Vol 7 (5) ◽  
pp. 13805-13838 ◽  
Author(s):  
M. T. Latif ◽  
P. Brimblecombe
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Atmospheric Aerosols ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Weight Fraction ◽  
Ozone Exposure ◽  
Before And After ◽  
Fine Mode ◽  
Active Substances

Abstract. Surfactants in atmospheric aerosols determined as methylene blue active substances (MBAS) and ethyl violet active substances (EVAS). The MBAS and EVAS concentrations can be correlated with surface tension as determined by pendant drop analysis. The effect of surface tension was more clearly indicated in fine mode aerosol extracts. The concentration of MBAS and EVAS was determined before and after ultrafiltration analysis using AMICON centrifuge tubes that define a 5000 Da (5 K Da) nominal molecular weight fraction. Overall, MBAS and to a greater extent EVAS predominates in fraction with molecular weight below 5 K Da. In case of aerosols collected in Malaysia the higher molecular fractions tended to be a more predominant. The MBAS and EVAS are correlated with yellow to brown colours in aerosol extracts. Further experiments showed possible sources of surfactants (e.g. petrol soot, diesel soot) in atmospheric aerosols to yield material having molecular size below 5 K Da except for humic acid. The concentration of surfactants from these sources increased after ozone exposure and for humic acids it also general included smaller molecular weight surfactants.

scholarly journals Studies on the antibacterial properties of the bile acids and some compounds derived from cholanic acid

1947 ◽  
Vol 134 (877) ◽  
pp. 523-537 ◽  
Keyword(s):  
Molecular Structure ◽  
Staphylococcus Aureus ◽  
Surface Tension ◽  
Bile Acids ◽  
Antibacterial Properties ◽  
Simple Relationship ◽  
The Relationship ◽  
Positive Complex ◽  
Cholanic Acid ◽  
Limiting Dilution

In this work the bile acids and certain of their derivatives have been studied with regard to their bacteriostatic power and relative activities in removing the Gram-positive complex from yeast. No correlation between these properties was obtained. A simple relationship was apparent, however, between the bacteriostatic activities of the compounds and their ability to depress the surface tension of the metabolism medium. The limiting dilution at which the 'active' bile acids were bacteriostatic for Staphylococcus aureus corresponded to a depression of the surface tension of the medium by approximately 4∙5 dynes. The relationship between bacteriostatic power and surface activity was only valid for this particular series of compounds of closely related molecular structure.

scholarly journals Role of membranes in bile formation. Comparison of the composition of bile and a liver bile-canalicular plasma-membrane subfraction

1976 ◽  
Vol 154 (3) ◽  
pp. 589-595 ◽  
Author(s):  
W H. Evans ◽  
T Kremmmer ◽  
J G. Culvenor
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Bile Acids ◽  
Secretory Process ◽  
Major Protein ◽  
Outer Face ◽  
Ph Optimum ◽  
Bile Formation ◽  
Canalicular Membrane ◽  
Bile Canalicular Membrane

1. Enzymes, proteins, glycoproteins and lipids of rodent bile were compared with those of a plasma-membrane subfraction originating from the hepatocyte bile-canalicular membrane. 2. Three bile-canalicular glycoprotein enzyme activities were detected in bile. Comparison of the pH optimum and immunoinhibition properties of membrane and bile 5′-nucleotidase activity indicated that they were the same enzyme. Correspondence between membrane and bile alkaline phosphodiesterases also suggested that they were the same enzymes. Activities of Mg2+-stimulated adenosine triphosphatase, a lipid-dependent intrinsic membrane protein, and galactosyltransferase, a Golgi membrane marker, were not detected in bile. 3. Rodent bile contained 15 polypeptide bands that differed radically from those of bile-canalicular membranes. Bands that may correspond in molecular weight to liver plasma-membrane glycoproteins were present at low staining intensities in bile. A major protein of apparent molecular weight 49 500 was present, and albumin was detected by immunodiffusion. 4. The lipid composition of bile and bile-canalicular membrane also differed. Phosphatidylcholine accounted for 82% of rat bile phospholipids, and only trace amounts of phosphatidylinositol, phosphatidylserine and sphingomyelin were present. 5. The results indicate that in healthy animals, the bile-canalicular membrane is refractory to the action of bile acids during the secretory process. The presence of only small amounts of bile-canalicular membrane components, especially glycoprotein enzymes located at the outer face of the membrane, suggests that these are released from the membrane by bile acids after secretion of bile into the canalicular spaces.

Cytosol-nucleus traffic and colocalization with FXR of conjugated bile acids in rat hepatocytes

2008 ◽  
Vol 295 (1) ◽  
pp. G54-G62 ◽  
Author(s):  
Maria J. Monte ◽  
Ruben Rosales ◽  
Rocio I. R. Macias ◽  
Valeria Iannota ◽  
Almudena Martinez-Fernandez ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Bile Acids ◽  
Nuclear Receptors ◽  
Rat Hepatocytes ◽  
Nuclear Volume ◽  
Farnesoid X Receptor ◽  
Nuclear Accumulation ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Rat Liver Cells

Bile acids (BAs) are natural ligands of nuclear receptors, in particular farnesoid X receptor (FXR). Whether, in addition to protein-mediated cytosolic-nuclear BA translocation, other mechanisms are involved in the access of BAs to nuclear FXR was investigated. When rat hepatocytes were incubated with radiolabeled taurocholic acid, taurodeoxycholic acid, taurochenodeoxycholic acid, and tauroursodeoxycholic acid, their nuclear accumulation was proportional to their intracellular levels. With the use of flow cytometry analysis, the accumulation by nuclei isolated from rat liver cells was found to differ for several fluorescent compounds of similar molecular weight and different charge, including fluorescein-tagged BAs [cholylglycyl amidofluorescein (CGamF), ursodeoxycholylglycyl amidofluorescein, or chenodeoxycholylglycyl amidofluorescein]. When we varied nuclear volume by incubation with different sucrose concentrations, a similar relationship between nuclear volume and content of FITC and 4-kDa FITC-dextran was found. In contrast, this relationship was markedly lower for CGamF. Confocal microscopy studies revealed that fluorescein-tagged BAs, but also FITC or 10-kDa FITC-dextran were found in the nuclear envelope and concentrated in regions where DNA was less densely packed. In contrast to the cytosolic subcellular localization of peroxisome proliferator-activated receptor-α, FXR and nucleolin (a marker of transcriptional active chromatin) were also localized by immunoreactivity in these intranuclear regions. In conclusion, although intranuclear levels of small organic molecules including conjugated BAs depend on their concentrations in the extranuclear space, the existence of certain molecular selectivity (not strictly dependent on molecular weight or charge) suggests that, in addition to simple diffusional exchange, other mechanisms may be also involved in determining their overall nuclear content in regions where these compounds coincide and may interact with nuclear receptors such as FXR.

The Surface Tension of Rubber Solutions

1931 ◽  
Vol 4 (3) ◽  
pp. 354-360
Author(s):  
G. W. Shacklock
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Surface Tension ◽  
Benzene Solution ◽  
Rubber Particle ◽  
Mechanical Action ◽  
The Past ◽  
Pure Product ◽  
Simple Molecules ◽  
Improved Methods

Abstract During the past few years much attention has been paid to the constitution of raw rubber. The much improved methods of production of plantation rubber have resulted in a reasonably pure product available for investigation, and chemical analysis undoubtedly shows an empirical formula of C5H8 for the hydrocarbon. From this point onward, knowledge becomes less certain. Osmotic pressure and molecular weight measurements give no confirmation of a simple molecular structure, but show, in benzene solution, a behavior comparable with that of colloids. This is supported by experiments on swelling and viscosity, and by ultramicroscopic examination, all of which lead to the conclusion that rubber is a lyophilic colloid. Hence arose the concept that the rubber particle is a polymer of simple molecules of formula C5H8 (possibly isoprene), such a structure being in agreement with the production of rubber-like substances by the action of sodium upon isoprene and butadiene (Harries, Annalen, 395, 211 (1912)). The decrease in viscosity of a rubber solution with increasing periods of mastication of the rubber is hence regarded as a measure of depolymerization due to mechanical action; the increased ease of solution after mastication is confirmatory evidence.

Molecular weight dependence and end-group effects on the surface tension of poly(dimethylsiloxane)

1993 ◽  
Vol 26 (12) ◽  
pp. 3069-3074 ◽  
Author(s):  
Claire Jalbert ◽  
Jeffrey T. Koberstein ◽  
Iskender Yilgor ◽  
Paula Gallagher ◽  
Val Krukonis
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Molecular Weight Dependence ◽  
End Group ◽  
Group Effects
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