A reassessment of the double isotope ratio (C-13)O/C(O-18) in molecular clouds

1989 ◽  
Vol 341 ◽  
pp. 293 ◽  
Author(s):  
David K. Taylor ◽  
R. L. Dickman
Keyword(s):  
Isotope Ratio ◽  
Molecular Clouds ◽  
O 18 ◽  
Double Isotope

scholarly journals Oxygen isotope ratio studies in the Galactic center region

2013 ◽  
Vol 9 (S303) ◽  
pp. 123-125
Author(s):  
JiangShui Zhang ◽  
Lulu Sun ◽  
Jianjie Qiu ◽  
Dengrong Lu ◽  
Min Wang
Keyword(s):  
Oxygen Isotope ◽  
Intensity Ratio ◽  
Isotope Ratio ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Metal Enrichment ◽  
Oxygen Isotope Ratio ◽  
Integrated Intensity ◽  
Sgr A ◽  
Nuclear Processing

AbstractUsing the Delingha 13.7 m telescope with a 9-beam SIS superconducting receiver installed, we carried out mapping of C18O and C17O J = (1 − 0) toward molecular clouds in the central molecular zone (CMZ) and in the halo of our galaxy. From the integrated intensity ratio of C18O to C17O, the isotope ratio 18O/17O ratio can be estimated, which is considered to be one of the most useful tracers of nuclear processing and metal enrichment. Here preliminary results are presented toward Sgr A, Sgr B2, Sgr C, Sgr D, and the 1.°3 complex in the CMZ and M+5.3–0.3 in the halo.

Double isotope-ratio thermometers: The influence of emission time scales

1999 ◽  
Vol 59 (5) ◽  
pp. 2660-2669 ◽  
Author(s):  
V. E. Viola ◽  
K. Kwiatkowski ◽  
W. A. Friedman
Keyword(s):  
Time Scales ◽  
Isotope Ratio ◽  
Emission Time ◽  
Double Isotope

Isospin independence of the H–He double isotope ratio “thermometer”

1998 ◽  
Vol 416 (1-2) ◽  
pp. 56-61 ◽  
Author(s):  
G.J Kunde ◽  
S Gaff ◽  
C.K Gelbke ◽  
T Glasmacher ◽  
M.J Huang ◽  
...  
Keyword(s):  
Isotope Ratio ◽  
Double Isotope

scholarly journals Choice of precursors for the measurement of protein turnover by the double-isotope method. Application to the study of mitochondrial proteins

1978 ◽  
Vol 176 (3) ◽  
pp. 919-926 ◽  
Author(s):  
R J Burgess ◽  
J H Walker ◽  
R J Mayer
Keyword(s):  
Solvent Extraction ◽  
Nucleic Acids ◽  
Protein Turnover ◽  
Isotope Ratio ◽  
Subcellular Fractions ◽  
Turnover Rates ◽  
Extraction Procedures ◽  
Mitochondrial Fractions ◽  
Double Isotope ◽  
Submitochondrial Fractions

1. The double-isotope concept [Arias, Doyle & Schimke (1969) J. Biol. Chem. 224, 3303–3315] for the measurement of protein turnover was used to estimate the turnover of proteins in subcellular and submitochondrial fractions prepared from rat liver. 2. Double-isotope experiments with [3H]leucine as first precursor and [14C]leucine as second precursor were used to measure the turnover rates of proteins in subcellular and submitochondrial fractions. Solvent extraction procedures designed to remove lipids and nucleic acids from trichloroacetic acid precipitates only changed the isotope ratio of the microsomal fraction. It was not possible to measure turnover of proteins in mitochondrial and submitochondrial fractions with these precursors. 3. Double-isotope experiments were designed to minimize first-precursor reutilization by employing NaH14CO3. [3H]Arginine was used as second precursor. The turnover rates of protein in subcellular and submitochondrial fractions was measured. Solvent extraction procedures designed to remove lipids and nucleic acids showed changes in the isotope ratio for all subcellular fractions, especially in microsomal and detergent-soluble mitochondrial fractions. Isotope ratios of precipitates after solvent extraction indicate that, whereas considerable heterogeneity exists for the average rates of protein turnover in subcellular fractions, little heterogeneity is observed in the average rates of protein turnover in submitochondrial fractions.

scholarly journals 7. Carbon Isotope Ratio in Comets and Interstellar Matter

1977 ◽  
Vol 39 ◽  
pp. 499-503 ◽  
Author(s):  
V. Vanysek
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Molecular Clouds ◽  
Carbon Isotope Ratio ◽  
Stellar Atmospheres ◽  
Interstellar Matter ◽  
Interstellar Molecular Clouds

The 12C/13C isotope ratio in the interstellar medium and in stellar atmospheres is discussed and compared to the value found in the solar system and especially in comets. The cometary value (≥ 100) tends to be slightly above the terrestrial value (89) and is definitively higher than that for interstellar molecular clouds (about 30 to 50). This result implies that comets are not of interstellar origin.

Nuclear temperature measurements with the double isotope ratio technique: Influence of the experimental conditions

2000 ◽  
Vol 8 (3) ◽  
pp. 355-360 ◽  
Author(s):  
P. M. Milazzo ◽  
G. Vannini ◽  
M. Bruno ◽  
N. Colonna ◽  
M. D’Agostino ◽  
...  
Keyword(s):  
Isotope Ratio ◽  
Temperature Measurements ◽  
Experimental Conditions ◽  
Nuclear Temperature ◽  
Double Isotope
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