Controlling the diversity of ion-induced fragmentation pathways by N-methylation of amino acids

2021 ◽  
Author(s):  
Dario Barreiro ◽  
Chiara Nicolafrancesco ◽  
Jaroslav Kocisek ◽  
Alberto Luna ◽  
Janina Kopyra ◽  
...  
Keyword(s):  
Amino Acids ◽  
Theoretical Study ◽  
Low Energy ◽  
Fragmentation Pathways

We present a combined experimental and theoretical study of the fragmentation of singly and doubly N−methylated glycine (sarcosine and N,N−dimethyl glycine, respectively) induced by low-energy (keV) O^6+ ions. Multicoincidence mass...

Annihilation Dynamics of Positrons in Molecular Environments: Theoretical Study of Low-Energy Positron-C2H4Scattering

1996 ◽  
Vol 77 (6) ◽  
pp. 1028-1031 ◽  
Author(s):  
Euclimar P. da Silva ◽  
José S. E. Germano ◽  
Marco A. P. Lima
Keyword(s):  
Theoretical Study ◽  
Low Energy

Theoretical Study of the Fragmentation Pathways of Norbornane in Its Doubly Ionized Ground State

2007 ◽  
Vol 111 (42) ◽  
pp. 10834-10848 ◽  
Author(s):  
Stefan Knippenberg ◽  
Balázs Hajgató ◽  
Jean-Pierre François ◽  
Michael S. Deleuze
Keyword(s):  
Ground State ◽  
Theoretical Study ◽  
Fragmentation Pathways

scholarly journals The effect of protein- and non-protein-nitrogen supplements to maize silage on total amino acid supply in young cattle

1982 ◽  
Vol 48 (3) ◽  
pp. 527-541 ◽  
Author(s):  
B. R. Cottrill ◽  
D. E. Beever ◽  
A. R. Austin ◽  
D. F. Osbourn
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Amino Acid ◽  
Dietary Protein ◽  
Fish Meal ◽  
Metabolizable Energy ◽  
Low Energy ◽  
Maize Silage ◽  
Protein Nitrogen ◽  
Microbial N

1. A total of six diets based on maize silage were formulated to examine the effect of protein- and non-protein-nitrogen, and energy supplementation on the flow of amino acids to the small intestine and the synthesis of microbial amino acids in the rumen of growing cattle. All diets contained 24 g totai nitrogen (N)/kg dry matter (DM), of which 550 g N/kg total N was supplied by either urea or fish meal. Four diets contained low levels of barley (estimated total dietary metabolizable energy content of 10·4 M J/kgDM) and urea-N and fish meal-N were supplied in the ratios 3:1, 1·4:1, 0·6:1 and 0·3:1. The other two diets contained between 300 and 400 g barley/kg total diet (11·3 MJ metabolizable energy/kg DM) and the urea-N to fish meal-N ratios were 3:1 and 0·3:1.2. On the four low-energy diets, fish meal inclusion tended to reduce the extent of organic matter (OM) digestion in the rumen but significantly increased duodenal amino acid supply (P< 0·05) in a quadratic manner. Microbial-N synthesis was increased by the two intermediate levels of fish meal supplementation but declined at the highest level of inclusion. With increasing levels of fish meal inclusion, a greater proportion of the dietary protein was found to escape rumen degradation and the apparent degradabilities of fish meal and maize-silage protein of all four diets were estimated to be 0·22 and 0·73 respectively.3. The substitution of barley for part of the maize silage enhanced duodenal supply of amino acids, irrespective of the form of the N supplement, and stimulated microbial amino acid synthesis. For all diets efficiency of microbial-N synthesis was found to vary between 22·5 and 46 g N/kg rumen-digested OM. Contrary to what was found for low-energy diets, the inclusion of fish meal tended to reduce the flow of dietary protein to the small intestine, but these differences were not statistically significant.4. The results appertaining to microbial synthesis, dietary protein degradabilities and duodenal amino acid flow for all diets are discussed in relation to the Agricultural Research Council (1980) proposals for the protein requirements of ruminants, and the production responses observed when similar diets were fed to growing cattle.

scholarly journals Theoretical Study of Plasmon Losses in Low-energy Photoemission Spectra

2012 ◽  
Vol 10 ◽  
pp. 145-148 ◽  
Author(s):  
Yusuke Ohori ◽  
Hiroshi Shinotsuka ◽  
Misato Kazama ◽  
Takashi Fujikawa
Keyword(s):  
Theoretical Study ◽  
Low Energy

scholarly journals Low Energy Diet-induced and Bariatric Surgery-induced Weight Loss Decreases Branched-chain and Aromatic Amino Acids in Plasma and Tissue (P21-078-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Zhanxuan Wu ◽  
Karl Fraser ◽  
Marlena Kruger ◽  
Garth Cooper ◽  
Anne-Thea McGill ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Amino Acids ◽  
Weight Loss ◽  
Aromatic Amino Acids ◽  
Fold Change ◽  
Low Energy ◽  
Post Surgery ◽  
T1 And T2 ◽  
Branched Chain ◽  
Low Energy Diet

Abstract Objectives Plasma levels of branched-chain amino acids (BCAA) and aromatic amino acids (AAA) phenylalanine (phe) and tyrosine (tyr) have been associated with obesity, insulin resistance and risk of type 2 diabetes. This study aimed to investigate the response of circulating plasma and tissue levels of BCAA and AAA to weight loss, and to correlate the level of these metabolites in plasma and tissue in obese women. Methods 28 obese (mean BMI 46.2 kg/m2) women underwent low energy diet (LED)-induced weight loss (−9.2 ± 4.2 kg) followed by bariatric surgery-induced weight loss (−23.6 ± 2.5 kg). Plasma at baseline (t0), post-LED/pre-surgery (t1) and 6-month post-surgery (t2) as well as biopsies of subcutaneous abdomen adipose tissue (SAfat), superficial thigh adipose tissue (Tfat) and vastus lateralis thigh muscle (Tmuscle) at both t1 and t2 were collected, and profiled using mass spectrometry-based metabolomics approach. Paired t-tests were applied to assess between-timepoint differences, and Pearson correlation used to calculate correlation coefficient of metabolite levels between plasma and tissue. Results Plasma BCAA and AAA were all significantly reduced post-LED at t1 (fold-change of 0.76–0.85 for val, leu, ile, tyr and phe, P < 0.05) and 6-month post-surgery at t2 (fold-change of 0.74–0.85 for val, leu, ile, tyr and phe, P < 0.05) as compared to baseline t0; but not significant between t1 and t2, although trends of decrease were observed. Among the 3 tissue biopsies, only SAfat showed significantly decreased levels of tyr, leu and ile at t2 compared to t1 (fold-change for tyr 0.63, leu 0.66, ile 0.68, P < 0.05). In addition, plasma levels of val and ile were correlated with Tfat levels at both t1 and t2 (r2 = 0.47–0.57), and that of val, ile and leu were correlated with Tmuscle at t1 only (r2 = 0.64–0.67). Conclusions Circulating levels of BCAA and AAA were decreased by weight loss interventions. The decrease following an LED program was sustained after bariatric surgery without further significant decrease. Bariatric surgery also decreased BCAA levels in SAfat; moreover, our data suggested that plasma BCAA levels correlated well with peripheral tissue Tfat and Tmuscle. Funding Sources The New Zealand National Science Challenge High-Value Nutrition program.

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