scholarly journals The structure of surface films. Part XVII.—γ hydroxy-stearic acid and its lactone

1933 ◽  
Vol 140 (840) ◽  
pp. 223-226 ◽  
Keyword(s):  
Stearic Acid ◽  
Aqueous Solutions ◽  
Surface Pressure ◽  
Surface Films ◽  
Hydroxy Stearic Acid ◽  
Monomolecular Films ◽  
Made In

This paper describes observations, mostly made in 1924 and not hitherto published in detail,* on the surface pressure of γ hydroxy-stearic acid (I) and its lactone (II) spread as monomolecular films on aqueous solutions. CH3 3 CH3 3 (CH 2 ) 13 (CH 2 ) 13 CHOH CH CH 2 CH 2 CH 2 O COOH CH 2 – CO I II Most of the measurements were made with the modification of Langmuir’s apparatus described in Parts I and II of this series of papers,† in which jets of air prevent the film passing the ends of the float. A few confirmatory observations have been made since, with the apparatus of Adam and Jessop, in which thin metallic ribbons block these gaps. The acid and lactone were kindly given me by Dr. P. W. Clutterbuck, of Manchester University.

scholarly journals The structure of surface films. Part XVIII. ─The effect of alkalinity in the underlying solution on films of fatty acids

1933 ◽  
Vol 142 (847) ◽  
pp. 401-415 ◽  
Keyword(s):  
Fatty Acids ◽  
Acid Solution ◽  
Aqueous Solutions ◽  
Complete Solution ◽  
Alkaline Solutions ◽  
Carboxyl Group ◽  
Surface Films ◽  
Electrolytic Dissociation ◽  
End Groups ◽  
Monomolecular Films

Historical . It has been known for some time that extensive changes occur in monomolecular films of fatty acids on aqueous solutions, as the alkalinity or acidity is varied. These changes are of at least tow kinds; changes in the packing of the molecules in the coherent types of film, and changes in the lateral adhesion between molecules have already been described. Thus Adam found changes in the packing of the molecules in the condensed films on changing from neutral to acid solution; and also a change from condensed to gaseous or vapour expanded films, on changing from natural to strongly alkaline solutions. The second of those effects was considered to be due to a decrease in the lateral adhesion between the molecules, caused by the development of similar electric charges on the end groups, through electrolytic dissociation of the carboxyl group on alkaline solutions. On alkaline solutions, it has previously been noted that the films contract spontaneously; Adam called this "solution," but did not examine it in detail; Lyons and Rideal believed it to be not a complete solution, but the formation of a bimolecular layer two molecules thick; Zocher and Stiebel, by ultramicroscopic examintion, concluded that this disappearance of the film was due to a partial collapse into thick, localized aggregates, not into a uniform bimolecular film.

scholarly journals Fatty Acid Esters of Hydroxy Fatty Acids (FAHFAs) Are Associated With Diet, BMI, and Age

2021 ◽  
Vol 8 ◽  
Author(s):  
Teresa Kellerer ◽  
Karin Kleigrewe ◽  
Beate Brandl ◽  
Thomas Hofmann ◽  
Hans Hauner ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Weight Loss ◽  
Fatty Acid ◽  
Stearic Acid ◽  
Palmitic Acid ◽  
Fatty Acid Esters ◽  
Obese Patients ◽  
Hydroxy Stearic Acid ◽  
Diabetic Status ◽  
Acid Esters

Background: Fatty acid esters of hydroxy fatty acids (FAHFAs) are a group of fatty acids with potential anti-inflammatory and anti-diabetic effects. The blood levels of FAHFAs and their regulation in humans have hardly been studied.Objective: We aimed to investigate serum FAHFA levels in well-characterized human cohorts, to evaluate associations with age, sex, BMI, weight loss, diabetic status, and diet.Methods: We analyzed levels of stearic-acid-9-hydroxy-stearic-acid (9-SAHSA), oleic-acid-9-hydroxy-stearic-acid (9-OAHSA) and palmitic-acid-9-hydroxy-palmitic-acid (9-PAHPA) as well as different palmitic acid-hydroxy-stearic-acids (PAHSAs) by HPLC-MS/MS with the use of an internal standard in various cohorts: A cohort of different age groups (18–25y; 40–65y; 75–85y; Σn = 60); severely obese patients undergoing bariatric surgery and non-obese controls (Σn = 36); obese patients with and without diabetes (Σn = 20); vegetarians/vegans (n = 10) and omnivores (n = 9); and young men before and after acute overfeeding with saturated fatty acids (SFA) (n = 15).Results: Omnivores had substantially higher FAHFA levels than vegetarians/vegans [median (25th percentile; 75th percentile) tFAHFAs = 12.82 (7.57; 14.86) vs. 5.86 (5.10; 6.71) nmol/L; P < 0.05]. Dietary overfeeding by supplementation of SFAs caused a significant increase within 1 week [median tFAHFAs = 4.31 (3.31; 5.27) vs. 6.96 (6.50; 7.76) nmol/L; P < 0.001]. Moreover, obese patients had lower FAHFA levels than non-obese controls [median tFAHFAs = 3.24 (2.80; 4.30) vs. 5.22 (4.18; 7.46) nmol/L; P < 0.01] and surgery-induced weight loss increased 9-OAHSA level while other FAHFAs were not affected. Furthermore, significant differences in some FAHFA levels were found between adolescents and adults or elderly, while no differences between sexes and between diabetic and non-diabetic individuals were detected.Conclusions: FAHFA serum levels are strongly affected by high SFA intake and reduced in severe obesity. Age also may influence FAHFA levels, whereas there was no detectable relation with sex and diabetic status. The physiological role of FAHFAs in humans remains to be better elucidated.Trial Registration: All studies referring to these analyses were registered in the German Clinical Trial Register (https://www.drks.de/drks_web/) with the numbers DRKS00009008, DRKS00010133, DRKS00006211, and DRKS00009797.

scholarly journals Impurities and Homogeneous Crystal Nucleation in Aqueous Solutions - An Overview

2019 ◽  
Vol 16 (3) ◽  
pp. 198-208
Author(s):  
C. K. Mahadevan
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Research Group ◽  
Present Author ◽  
Crystal Nucleation ◽  
Nucleation Process ◽  
Nucleation Parameters ◽  
The Past ◽  
Homogeneous Crystal ◽  
Made In

Nucleation process is the most important stage in the formation of a crystal and has attracted the attention of researchers due to its importance in many technological and biological contexts. As the presence of impurities affects the nucleation process significantly, several studies have been made in the past to understand it. In this article is presented an overview of various studies made to understand the effect of soluble impurities on the crystal nucleation parameters of certain important materials in aqueous solution focusing the results reported by the research group of the present author.

The signature 10-hydroxy stearic acid thought to correlate with infectivity in oocysts of Cryptosporidium species is an artifact

Lipids ◽  
1998 ◽  
Vol 33 (8) ◽  
pp. 829-833
Author(s):  
Robert S. Burkhalter ◽  
Carol A. Smith ◽  
David C. White ◽  
Ronald Fayer ◽  
Andrew B. White
Keyword(s):  
Stearic Acid ◽  
Cryptosporidium Species ◽  
Hydroxy Stearic Acid

Sensing behavior of perovskites GdCo1−xCuxO3 prepared by solution and ultrasonic-assisted aerosol methods.

2004 ◽  
Vol 828 ◽  
Author(s):  
Carlos R. Michel ◽  
Edgar R. López ◽  
Arturo Chávez
Keyword(s):  
Aqueous Solutions ◽  
Solution Method ◽  
Spherical Particles ◽  
Electrical Measurements ◽  
Gas Sensitivity ◽  
Semiconductor Behavior ◽  
Ultrasonic Assisted ◽  
Method Yield ◽  
Precursor Powders ◽  
Made In

ABSTRACTPolycrystalline samples of GdCo1−xCuxO3 (x=0, 0.15, 0.3), were prepared by two different routes: solution and ultrasonic-assisted aerosol decomposition. For both procedures, aqueous solutions containing stoichiometric amounts of Gd(NO3)36H2O, Co(NO3)26H2O and Cu(NO3)22.5H2O were used. In the solution method, the aqueous solutions were heat-dried at 76°C obtaining precursor powders, these were calcined from 80 to 950°C, in air. In the aerosol method, very small droplets were produced by an ultrasonic generator, then a flow of oxygen transported the mist through a tubular furnace, previously heated at 950°C. Solvent evaporation and chemical reaction takes place at that temperature, and the resulting powder was collected by filtration. X-ray powder diffraction was used to identify the formation of target phases. Surface microstructure of powders was analyzed by SEM, and showed that solution method produced sub-micron particles with irregular shape, whereas the aerosol method yield micron-sized hollow spherical particles. In order to determine gas sensitivity vs. temperature, electrical measurements were made in air, O2 and CO2, from room temperature to 650°C. The results showed a semiconductor behavior and a moderate gas sensitivity for samples prepared by solution method. However, unreliable data were registered for samples made by the aerosol route, caused by short connectivity between particles.

12-Hydroxy stearic acid appended new amphiphilic scaffolds for selective capture of hydrogen halides through supramolecular hydrogelation

2020 ◽  
Vol 44 (10) ◽  
pp. 3828-3832 ◽  
Author(s):  
Ankita Sharma ◽  
Arindam Gupta ◽  
Priyanka Tiwari ◽  
Anindya Basu ◽  
Anita DuttKonar
Keyword(s):  
Stearic Acid ◽  
Hydrogen Halides ◽  
Hydroxy Stearic Acid

12-Hydroxy stearic acid appended with various aromatic C-terminal residues serves as a new amphiphilic scaffold for selective halide capture.

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