scholarly journals Quantitative Determination of Cysteine and Cystine in Peptides and Proteins Using Hydriodic Acid

1971 ◽  
Vol 24 (4) ◽  
pp. 1241 ◽  
Author(s):  
AS Inglis ◽  
PW Nicholls ◽  
CM Roxburgh
Keyword(s):  
Amino Acid ◽  
Hydrochloric Acid ◽  
Chemical Modification ◽  
Quantitative Determination ◽  
Amino Acid Analysis ◽  
Hydriodic Acid ◽  
Operating Conditions ◽  
Simple Alternative ◽  
Amino Acid Analyser

Determination of the composition of proteins by amino acid analysis after hydrochloric acid hydrolysis is unsatisfactory for cystine which is not all recoverable. When proteins were hydrolysed in hydriodic acid, half-cystine was released quickly and without measurable loss as cystine with freshly distilled acid and as cystine plus cysteine with hydriodic acid containing hypophosphorous acid_ The necessary alterations to the normal operating conditions of an amino acid analyser to enable the resolution of cysteine from proline are discussed. This procedure for cystine analysis provides a simple alternative to determinations involving chemical modification of the amino acid.

Quantitative determination of free amino acids with automatic amino acid analyser in liver cirrhosis blood plasma

1966 ◽  
Vol 1 (3) ◽  
pp. 75-75
Author(s):  
S. Tanaka ◽  
K. Hattori ◽  
Y. Katoo ◽  
S. Suga ◽  
A. Ishiwara ◽  
...  
Keyword(s):  
Amino Acids ◽  
Liver Cirrhosis ◽  
Amino Acid ◽  
Quantitative Determination ◽  
Blood Plasma ◽  
Free Amino Acids ◽  
Free Amino ◽  
Amino Acid Analyser

Studies of Glutamate Dehydrogenase: Chemical Modification and Quantitative Determination of Tryptophan Residues

1974 ◽  
Vol 43 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Veit Witzemann ◽  
Rudolf Koberstein ◽  
Horst Sund ◽  
Ihab Rasched ◽  
Hans Jornvall ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Quantitative Determination ◽  
Glutamate Dehydrogenase ◽  
Tryptophan Residues

scholarly journals A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

2021 ◽  
Author(s):  
Wassim Habchi ◽  
Philippe Vergne
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Film Thickness ◽  
Quantitative Determination ◽  
Excellent Agreement ◽  
Operating Conditions ◽  
Pure Rolling ◽  
Minimum Film Thickness

Abstract The current work presents a quantitative approach for the prediction of minimum film thickness in elastohydrodynamic lubricated (EHL) circular contacts. In contrast to central film thickness, minimum film thickness can be hard to accurately measure, and it is usually poorly estimated by classical analytical film thickness formulae. For this, an advanced finite-element-based numerical model is used to quantify variations of the central-to-minimum film thickness ratio with operating conditions, under isothermal Newtonian pure-rolling conditions. An ensuing analytical expression is then derived and compared to classical film thickness formulae and to more recent similar expressions. The comparisons confirmed the inability of the former to predict the minimum film thickness, and the limitations of the latter, which tend to overestimate the ratio of central-to-minimum film thickness. The proposed approach is validated against numerical results as well as experimental data from the literature, revealing an excellent agreement with both. This framework can be used to predict minimum film thickness in circular elastohydrodynamic contacts from knowledge of central film thickness, which can be either accurately measured or rather well estimated using classical film thickness formulae.

THE DETERMINATION OF ZIRCONIUM WITH BENZOYLPHENYLHYDROXYLAMINE

1960 ◽  
Vol 38 (12) ◽  
pp. 2488-2492 ◽  
Author(s):  
D. E. Ryan
Keyword(s):  
Hydrochloric Acid ◽  
Quantitative Determination ◽  
Sulphuric Acid ◽  
Rare Earths ◽  
Acid Solutions ◽  
Constant Composition ◽  
Hydrochloric Acid Solutions

Zirconium is completely precipitated by benzoylphenylhydroxylamine from 0.5 N acid solutions. The complex formed in sulphuric acid solutions has a constant composition, Zr(C13H10O2N)4, and is used for the direct weighing of zirconium; the factor is 0.0970. The product precipitated from hydrochloric acid solutions must be ignited to the oxide. The reaction is sensitive, 1 p.p.m. of zirconium being detectable, and quantitative determination of 0.2 mg is possible. Thorium and the rare earths do not interfere.

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