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Ehleringer et al. 10.1073/pnas.0712228105. |
Fig. 5. Schematic representation of our model for the incorporation of H and O isotopes in human hair. See SI Table 1 and text for discussion and descriptions of parameters.
Table 1. Notation and parameter derivation for the hair isotope model
|
Parameter |
Description |
Value |
Source |
|
a |
Proportion of body water O derived from drinking water |
0.62 |
|
|
b |
Proportion of body water O derived from diet |
0.14 |
1 |
|
c |
Proportion of body water O derived from O2 |
0.24 |
1 |
|
d |
Proportion of body water H derived from drinking water |
0.81 |
1 |
|
e |
Proportion of follicle water H derived from body water |
0.81 |
Assumed |
|
fd |
Fraction of H atoms derived from diet |
Eq. 2 |
|
|
fe |
Fraction of keratin H exchanged in vivo |
0.12 |
2 |
|
fs |
Fraction of nonexchanged keratin H fixed in vivo |
0.30 |
Tuned |
|
g1 |
Proportion of gut water derived from body water |
0.57 |
Tuned; 3 |
|
g2 |
Proportion of gut water derived from drinking water |
0.0 |
Assumed |
|
h |
Proportion of O in body water that is lost as fractionated water associated with breathing/evaporation |
0.14 |
1 |
|
j |
Proportion of O in body water lost as CO2 |
0.24 |
1 |
|
k |
Proportion of O in body water that is lost as unfractionated water |
0.62 |
1 |
|
m |
Proportion of H in body water that is lost as fractionated water associated with breathing/evaporation |
0.24 |
1 |
|
n |
Proportion of H in body water that is lost as unfractionated water |
0.76 |
1 |
|
d 2Hd |
H isotopic composition of diet |
-115‰ |
Ehleringer et al., unpublished work; Chesson et al., unpublished work |
|
d 2Hh |
H isotopic composition of hair |
Eq. 3 |
|
|
d 2Hwb |
H isotopic composition of body water |
Eq. 7 |
|
|
d 2Hwe |
H isotopic composition of drinking water |
Variable |
Tap water |
|
d 2Hwf |
H isotopic composition of follicle water |
Eq. 4 |
|
|
d 18Oh |
O isotopic composition of hair |
Eq. 1 |
|
|
d 18Owb |
O isotopic composition of body water |
Eq. 6 |
|
|
d 18Owe |
O isotopic composition of drinking water |
Variable |
Tap water |
|
d 18Od |
O isotopic composition of diet |
+26.0‰ |
Ehleringer et al., unpublished work; Chesson et al., unpublished work |
|
d 18OO2 |
O isotopic composition of O2 |
+23.5‰ |
4 |
|
d 18Owd |
O isotopic composition of food water |
d 18Od - 27.0‰ |
5 |
|
d 18Owg |
O isotopic composition of gut water |
Eq. 5 |
|
|
a ow |
Fractionation of O between carbonyl oxygen and water |
1.016 |
Tuned; 6 |
|
a fwlh |
Fractionation of H in water lost through breathing/evaporation |
0.94 |
1 |
|
a hw |
Hydrogen isotope fractionation during protein synthesis |
1.002 |
Tuned |
|
a o2 |
O2 fractionation between atmospheric O2 and absorbed O2 |
0.992 |
1 |
|
a fwlo |
Fractionation of O in body water lost through breathing/evaporation |
0.992 |
1 |
|
a co2 |
Fractionation of O between body water and CO2 |
1.038 |
1 |
See text for discussion.
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2. Bowen GJ, Chesson L, Nielson K, Cerling TE, Ehleringer JR (2005) Treatment methods for the determination of delta H-2 and delta O-18 of hair keratin by continuous-flow isotope-ratio mass spectrometry. Rapid Commun Mass Spectrom 19:2371-2378.
3. Malagelada J-R, Longstreth GF, Summerskill WHJ, Go VLW (1976) Measurement of gastric functions during digestion of ordinary solid meals in man. Gastroenterology 70:203-210.
4. Kroopnick P, Craig H (1972) Atmospheric oxygen: isotopic composition and solubility fractionation. Science 175:54-55.
5. Sternberg LSL, DeNiro MJ (1983) Biogeochemical implications of the isotopic equilibrium fractionation factor between the oxygen atoms of acetone and water. Geochim Cosmochim Acta 47:2271-2274.
6. Kreuzer-Martin HW, Lott MJ, Dorigan J, Ehleringer JR (2003) Microbe forensics: Oxygen and hydrogen stable isotope ratios in Bacillus subtilis cells and spores. Proc Nat Acad Sci USA 100:815-819.
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