Microfacies, Carbon and Oxygen Isotopes of the Late Archean
... chemical and physical processes of the oceans. Because oxygen is reactive and easily forms many oxides with other elements; the content of free oxygen can directly ...
... chemical and physical processes of the oceans. Because oxygen is reactive and easily forms many oxides with other elements; the content of free oxygen can directly ...
Fermentation of Glucose and Xylose to Hydrogen in the Presence of
... quotations, or any other material from the work of other people included in my thesis, published or otherwise, are fully acknowledged in accordance with the standard referencing practices. Furthermore, to the extent that I have included copyrighted material that surpasses the bounds of fair dealing ...
... quotations, or any other material from the work of other people included in my thesis, published or otherwise, are fully acknowledged in accordance with the standard referencing practices. Furthermore, to the extent that I have included copyrighted material that surpasses the bounds of fair dealing ...
Thesis proposal
... additional, stable neutron. The isotope generally has little effect on the chemical properties of an element, as these are chiefly determined by electronic configuration. Yet small differences in chemical behaviour of two isotopes of a given element do exist. For a given element in fixed environment ...
... additional, stable neutron. The isotope generally has little effect on the chemical properties of an element, as these are chiefly determined by electronic configuration. Yet small differences in chemical behaviour of two isotopes of a given element do exist. For a given element in fixed environment ...
Trophic discrimination of nitrogen stable isotopes in
... recently, several controlled feeding experiments on upper trophic level consumers in marine environments showed definitively that TDFGlu-Phe values vary significantly, and are often substantially lower than 7.6& (Germain et al. 2013; Bradley et al. 2014; Hoen et al. 2014). While the TDFGlu-Phe value ...
... recently, several controlled feeding experiments on upper trophic level consumers in marine environments showed definitively that TDFGlu-Phe values vary significantly, and are often substantially lower than 7.6& (Germain et al. 2013; Bradley et al. 2014; Hoen et al. 2014). While the TDFGlu-Phe value ...
David Rittenberg - National Academy of Sciences
... Work reported by Shemin and Rittenberg in 1945 on the utilization of glycine also led to important findings. Shemin himself, with much courage, ingested over a threeday period 66 g of [15N]glycine. At stated intervals blood was withdrawn and the 15N concentration of blood proteins was determined. Th ...
... Work reported by Shemin and Rittenberg in 1945 on the utilization of glycine also led to important findings. Shemin himself, with much courage, ingested over a threeday period 66 g of [15N]glycine. At stated intervals blood was withdrawn and the 15N concentration of blood proteins was determined. Th ...
actiona actionation of FFFFFrrrrractiona
... from carbohydrates and from some amino acids. In contrast, Abelson and Hoering (1961) pioneered the examination of intramolecular patterns of isotopic order. They studied the biosynthesis of amino acids, analyzing only the end products. However, they determined not only the δ values of the individua ...
... from carbohydrates and from some amino acids. In contrast, Abelson and Hoering (1961) pioneered the examination of intramolecular patterns of isotopic order. They studied the biosynthesis of amino acids, analyzing only the end products. However, they determined not only the δ values of the individua ...
Fractionation of the isotopes of carbon and hydrogen in biosynthetic
... from carbohydrates and from some amino acids. In contrast, Abelson and Hoering (1961) pioneered the examination of intramolecular patterns of isotopic order. They studied the biosynthesis of amino acids, analyzing only the end products. However, they determined not only the δ values of the individua ...
... from carbohydrates and from some amino acids. In contrast, Abelson and Hoering (1961) pioneered the examination of intramolecular patterns of isotopic order. They studied the biosynthesis of amino acids, analyzing only the end products. However, they determined not only the δ values of the individua ...
Stable Isotope Methods for the Study of the Nitrogen Cycle
... and “n” refers to the atomic number of an element “E”. There are more than 10 nitrogen isotopes known. Most of these isotopes are radioactive and highly unstable with longest half-life time for ...
... and “n” refers to the atomic number of an element “E”. There are more than 10 nitrogen isotopes known. Most of these isotopes are radioactive and highly unstable with longest half-life time for ...
Hydrogen energy
... through various processes, including electrolysis, photo-electrolysis, hightemperature decomposition and photo-biological water splitting. The commercial production of hydrogen by electrolysis of water achieves an efficiency of 75%; however, the cost of hydrogen is currently several times higher than ...
... through various processes, including electrolysis, photo-electrolysis, hightemperature decomposition and photo-biological water splitting. The commercial production of hydrogen by electrolysis of water achieves an efficiency of 75%; however, the cost of hydrogen is currently several times higher than ...
The Mg isotopic composition of Cenozoic seawater – evidence for a
... on both the GV Isoprobe P and the Thermo Neptune MC-ICP-MS, were found to have the same δ 25 Mg and δ 26 Mg values to within 0.18h (δ 26 Mg; 2σsd ). Plotted in three-isotope space (δ 25 Mg vs. δ 26 Mg) all measured samples (n = 117) fall on a line with a slope of 0.5239 ± 0.0014 (R 2 = 0.9978), cons ...
... on both the GV Isoprobe P and the Thermo Neptune MC-ICP-MS, were found to have the same δ 25 Mg and δ 26 Mg values to within 0.18h (δ 26 Mg; 2σsd ). Plotted in three-isotope space (δ 25 Mg vs. δ 26 Mg) all measured samples (n = 117) fall on a line with a slope of 0.5239 ± 0.0014 (R 2 = 0.9978), cons ...
Kinetic isotope effects of 12CH3D+OH and 13CH3D+OH from 278 to
... sink) fractionations is an underdetermined systems (e.g., Pohlman et al., 2009). Recent advances in mass spectrometry (Eiler et al., 2013; Stolper et al., 2014) and laser infrared spectroscopy (Ono et al., 2014; Wang et al., 2015) facilitate measurement of rare doubly substituted isotopologues. The ...
... sink) fractionations is an underdetermined systems (e.g., Pohlman et al., 2009). Recent advances in mass spectrometry (Eiler et al., 2013; Stolper et al., 2014) and laser infrared spectroscopy (Ono et al., 2014; Wang et al., 2015) facilitate measurement of rare doubly substituted isotopologues. The ...
Stable nitrogen isotopic fractionation associated with transamination
... The stable nitrogen isotope ratio of glutamic acid is increased by ∼8.0‰ during trophic level changes in ecological food webs. It has been hypothesized that significant isotopic fractionation occurs associated with glutamic acid metabolism during transamination or deamination in heterotrophic animal ...
... The stable nitrogen isotope ratio of glutamic acid is increased by ∼8.0‰ during trophic level changes in ecological food webs. It has been hypothesized that significant isotopic fractionation occurs associated with glutamic acid metabolism during transamination or deamination in heterotrophic animal ...
Measuring variations of δ18O and δ2H in atmospheric water vapour
... well as in terms of optimal calibration frequency is investigated; and (4) the response times of the measurement systems after a step change in isotope and water concentration are characterised. The structure of this paper follows the description and evaluation of these 4 characterisation steps. At ...
... well as in terms of optimal calibration frequency is investigated; and (4) the response times of the measurement systems after a step change in isotope and water concentration are characterised. The structure of this paper follows the description and evaluation of these 4 characterisation steps. At ...
Interaction of Urea with Amino Acids: Implications for Urea
... interaction sites for water. For both amino acids, also the sidechain CH2 groups and even the backbone show reduced interactions with urea due to the charge of the carboxyl group. This effect is slightly more pronounced for ASP than for GLU, since the backbone is separated from the carboxyl group by ...
... interaction sites for water. For both amino acids, also the sidechain CH2 groups and even the backbone show reduced interactions with urea due to the charge of the carboxyl group. This effect is slightly more pronounced for ASP than for GLU, since the backbone is separated from the carboxyl group by ...
PDF
... 100 mL) was washed sequentially with 6 M HCl, 6 M NaOH and water and then packed into a column and equilibrated with 15% AcOH in water (v/v). All 2 L of pale yellow filtrate was passed over this resin using a siphon under gravity, and the resin was washed with 500 mL of 15% AcOH in water (v/v) and wi ...
... 100 mL) was washed sequentially with 6 M HCl, 6 M NaOH and water and then packed into a column and equilibrated with 15% AcOH in water (v/v). All 2 L of pale yellow filtrate was passed over this resin using a siphon under gravity, and the resin was washed with 500 mL of 15% AcOH in water (v/v) and wi ...
Isotope Composition of Organic Matter in Seawater
... 15N (Farquhar et al., 1989; Needoba et al., 2003). Meanwhile, fractionation is also related to both temperature and availability of dissolved CO2 or inorganic N in surface ocean. For 14C isotope, the assumption is that the fractionation of 14C relative to 12C is twice that of 13C, reflecting the dif ...
... 15N (Farquhar et al., 1989; Needoba et al., 2003). Meanwhile, fractionation is also related to both temperature and availability of dissolved CO2 or inorganic N in surface ocean. For 14C isotope, the assumption is that the fractionation of 14C relative to 12C is twice that of 13C, reflecting the dif ...
Plankton trophodynamics at the subtropical convergence, Southern
... found a distinct gradient in d13CPOM in a transect crossing the STC near 688E, with depleted values associated with the cold southern and [CO2(aq)]-rich water mass relative to more enriched values in the warm northern and low [CO2(aq)] water mass. Gradients or regional differences in d13C or d15N im ...
... found a distinct gradient in d13CPOM in a transect crossing the STC near 688E, with depleted values associated with the cold southern and [CO2(aq)]-rich water mass relative to more enriched values in the warm northern and low [CO2(aq)] water mass. Gradients or regional differences in d13C or d15N im ...
13C analysis of amino acids in human hair using trimethylsilyl
... Several derivatization procedures have been used for the GC/C/IRMS analyses of amino acids, as summarized in Table 1. The most widely used methods for amino acid derivatization for GC/C/IRMS analysis involve a stepwise procedure of esterification of the carboxylic acid groups with an acidified alcohol ...
... Several derivatization procedures have been used for the GC/C/IRMS analyses of amino acids, as summarized in Table 1. The most widely used methods for amino acid derivatization for GC/C/IRMS analysis involve a stepwise procedure of esterification of the carboxylic acid groups with an acidified alcohol ...
Standard PDF - Wiley Online Library
... sented by glutamic acid (Glu), undergo significant isotopic fractionation during transamination/deamination, which often provide greater sensitivity for defining trophic position than bulk SIA (McClelland and Montoya 2002; Chikaraishi et al. 2007, 2009). Conversely, the canonical source AA, phenylal ...
... sented by glutamic acid (Glu), undergo significant isotopic fractionation during transamination/deamination, which often provide greater sensitivity for defining trophic position than bulk SIA (McClelland and Montoya 2002; Chikaraishi et al. 2007, 2009). Conversely, the canonical source AA, phenylal ...
Factors Controlling the Stable Nitrogen Isotopic Composition (δ15N
... each trophic step results in an increase in the δ15N signal of biomass (e.g. [5,6]). More recently, the δ15N of specific amino acids has been used to estimate trophic levels [7–9]. For application of stable isotopes in trophic ecology, lipids are sometimes removed from bulk biomass prior to stable i ...
... each trophic step results in an increase in the δ15N signal of biomass (e.g. [5,6]). More recently, the δ15N of specific amino acids has been used to estimate trophic levels [7–9]. For application of stable isotopes in trophic ecology, lipids are sometimes removed from bulk biomass prior to stable i ...
Trophic ecology of a green turtle breeding population
... al. 2009, Navarro et al. 2011). An isotopic niche is a proxy for an ecological niche and is influenced by what individuals consume (bionomic factors), as well as where they live (scenopoetic factors), and is typically represented by 2 or more stable isotope measurements of tissues from of a consumer ...
... al. 2009, Navarro et al. 2011). An isotopic niche is a proxy for an ecological niche and is influenced by what individuals consume (bionomic factors), as well as where they live (scenopoetic factors), and is typically represented by 2 or more stable isotope measurements of tissues from of a consumer ...
Strong, Low-Barrier Hydrogen Bonds May Be Available to Enzymes
... with the enzyme “bear-hugging” the transition state,18 suggests a relatively compact, semirigid environment at the enzyme active site and brings to mind the relatively immobile, structured environments of crystals, where there is evidence of short, possibly strong hydrogen bonds in some enzyme struc ...
... with the enzyme “bear-hugging” the transition state,18 suggests a relatively compact, semirigid environment at the enzyme active site and brings to mind the relatively immobile, structured environments of crystals, where there is evidence of short, possibly strong hydrogen bonds in some enzyme struc ...
Get PDF - Wiley Online Library
... 2008; Roberts et al., 2010]. The deglacial transition appears to have been characterized by multiple switches between glacial and Holocene-like circulation modes [e.g., Zahn and Stuber, 2002; Skinner et al., 2003; McManus et al., 2004; Skinner and Shackleton, 2004; Roberts et al., 2010] and possibly ...
... 2008; Roberts et al., 2010]. The deglacial transition appears to have been characterized by multiple switches between glacial and Holocene-like circulation modes [e.g., Zahn and Stuber, 2002; Skinner et al., 2003; McManus et al., 2004; Skinner and Shackleton, 2004; Roberts et al., 2010] and possibly ...
pdf link - Aaron Diefendorf
... respectively. Even though both classes of terpenoids have long been recognized as plant biomarkers, their potential use as phylogenetically specific d13C proxies remains largely unexplored. Little is known of how terpenoid abundance and carbon isotope composition vary either with plant phylogenetic p ...
... respectively. Even though both classes of terpenoids have long been recognized as plant biomarkers, their potential use as phylogenetically specific d13C proxies remains largely unexplored. Little is known of how terpenoid abundance and carbon isotope composition vary either with plant phylogenetic p ...