scholarly journals Radiocarbon Dating of Biochemically Characterized Hair

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 319-330 ◽  
Author(s):  
R. E. Taylor ◽  
P. E. Hare ◽  
Christine A. Prior ◽  
Donna L. Kirner ◽  
Lijun Wan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Radiocarbon Dating ◽  
Baseline Data ◽  
Data Support ◽  
Hair Samples ◽  
Before And After ◽  
Age Determinations

A series of 14C determinations have been obtained on hair samples principally from Holocene contexts that have been variously pretreated to examine different means of removing potential contamination. SEM photomicrographs have documented hair surfaces before and after different pretreatments. Amino-acid composition, C/N ratios and δ13C values have been obtained to biochemically characterize these samples and provide baseline data for future comparisons with less well-preserved samples. Our data support the view that appropriately pretreated hair samples can provide accurate 14C age determinations.

Carbohydrate and amino acid composition in phloem sap of Lolium perenne L. before and after defoliation

2004 ◽  
Vol 82 (11) ◽  
pp. 1594-1601 ◽  
Author(s):  
Véronique Amiard ◽  
Annette Morvan-Bertrand ◽  
Jean-Bernard Cliquet ◽  
Jean-Pierre Billard ◽  
Claude Huault ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Lolium Perenne ◽  
Rhopalosiphum Padi ◽  
Soluble Sugars ◽  
Phloem Sap ◽  
Lolium Perenne L ◽  
Before And After ◽  
Leaf Exudate

Carbohydrate and amino acid composition of phloem sap was studied in the grass Lolium perenne L., before and after defoliation. Leaf exudate was collected in a 5 mmol·L–1 EDTA solution from cut leaf blades or stubble, and phloem sap was obtained through excised aphid (Rhopalosiphum padi L.) stylets. Results indicate that leaf exudates obtained from leaves devoid of petiole might not be relevant predictors of carbohydrate content of pure phloem sap. Sucrose was the dominating carbohydrate, accounting for 93% of the total soluble sugars in the phloem sap. Myo-inositol, glucose, and fructose were present in trace amounts, while fructans, raffinose, and loliose have never been detected. Predominant amino acid in the phloem sap was glutamine followed by glutamate, aspartate, and serine. Phloem sap component concentration declined during the first hours following defoliation. Sucrose was the main sugar transported in the phloem sap of Lolium perenne, despite the fact that the product of fructan degradation was fructose and not sucrose. The results are discussed in relation with the physiological mechanisms that contribute to plant recovery after defoliation.Key words: fructan, sucrose, loliose, defoliation, phloem sap, amino acids.

Effect of maternal diet on the amino acid composition of human uterine fluid

2014 ◽  
Author(s):  
Alexandra Jayne Kermack ◽  
Ying Cheong ◽  
Nick Brook ◽  
Nick Macklon ◽  
Franchesca D Houghton
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Maternal Diet ◽  
Uterine Fluid
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