Academic literature on the topic 'Stable isotope tracers'

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Journal articles on the topic "Stable isotope tracers"

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Rosenblatt, J., and R. R. Wolfe. "Calculation of substrate flux using stable isotopes." American Journal of Physiology-Endocrinology and Metabolism 254, no. 4 (April 1, 1988): E526—E531. http://dx.doi.org/10.1152/ajpendo.1988.254.4.e526.

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The use of stable isotope tracers to calculate substrate kinetics in humans is favored over the use of radioactive isotopes because of their greater safety and versatility. However, potential complications not met when dealing with radioactive tracers are caused by 1) the natural occurrence of the stable isotope used as a tracer and 2) the necessity to administer the tracer in an amount that cannot be treated as "massless." We therefore found it desirable to derive a theoretically valid equation for calculating the rate of appearance, Ra, of a substrate under steady-state conditions using a stable isotope tracer. This theoretically valid equation yields results that differ from those of the equations conventionally used to calculate (endogenous) Ra in steady state. Quantitative determination of the error in one of these equations revealed that for tracers commonly used in metabolic studies the error is negligible, whereas the error made in the other equation is likely to be quite high in commonly encountered situations. Finally, to allow for proper use of different definitions of isotopic enrichment that have arisen from practical considerations, we use the results derived above to determine valid equations for Ra appropriate to the two prevalent definitions.
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Patterson, Kristine Y., and Claude Veillon. "Stable Isotopes of Minerals as Metabolic Tracers in Human Nutrition Research." Experimental Biology and Medicine 226, no. 4 (April 2001): 271–82. http://dx.doi.org/10.1177/153537020122600403.

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Enriched stable isotopes used as tracers have proven to be valuable in studies of the absorption and metabolism of minerals. Unlike radioisotopes, they can be used in high-risk population groups such as infants, children, and pregnant or lactating women. Estimates of mineral absorption can be made from the oral administration of a single tracer or from two tracers, one given orally and the other intravenously (IV). It is possible to determine the metabolism of the mineral with modeling based on the amount of the tracer or tracers in different biological samples. One of the key decisions in studies of this type is determining which enriched isotope and what amount to use. An example is given of calculations to estimate and compare the amounts of tracers needed for an absorption study. Methods for calculating the amounts of tracer in oral and IV doses are presented, and limits of detection and quantitation are discussed in terms of percent of enrichment and related to isotope ratio measurement precision. A general review of the use of mass spectrometric instruments for quantifying various stable isotopes is given.
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Cobelli, C., G. Toffolo, D. M. Bier, and R. Nosadini. "Models to interpret kinetic data in stable isotope tracer studies." American Journal of Physiology-Endocrinology and Metabolism 253, no. 5 (November 1, 1987): E551—E564. http://dx.doi.org/10.1152/ajpendo.1987.253.5.e551.

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In contrast to "weightless" radioactive tracers, stable isotope tracers have nonnegligible mass and are naturally present in the system, and the measured variable is a ratio of two isotopic species. These features do not allow stable isotopic tracer data analysis using straightforward analogy with radioactive tracer approaches, even though this practice is common. In this study, we present kinetic variables, models, and measurements for the analysis and interpretation of stable isotope tracer data. Assumptions and mathematical techniques for modeling the data when perturbation is both nonnegligible and negligible are discussed. Emphasis is placed on the rich information content of the dynamic portion of a stable isotope tracer curve and on the role of compartmental and noncompartmental modeling approaches for its interpretation. A presumed and commonly used analogy between the radioactive specific activity and stable isotopic enrichment is shown to be incorrect. We show that the proper analogue of specific activity is the tracer-to-tracee molar ratio. This variable is not a directly measurable one, but a formula is derived that allows its computation from the data. A method for reconstructing the time course in blood of the concentration component due to endogenous synthesis is presented. This allows measurement of the extent of the perturbation in the case where a nonweightless tracer is used. Special attention is given to data analysis originating from a multiple tracer experiment, a configuration necessary for studying more complex systems, e.g., the kinetics of interacting substrates.
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Kelleher, J. K., and T. M. Masterson. "Model equations for condensation biosynthesis using stable isotopes and radioisotopes." American Journal of Physiology-Endocrinology and Metabolism 262, no. 1 (January 1, 1992): E118—E125. http://dx.doi.org/10.1152/ajpendo.1992.262.1.e118.

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Important syntheses in living systems occur by condensation reactions of the type nA----1B (where n is the number of A molecules needed to synthesize 1 molecule of B). Quantitative relationships for estimating the rate of synthesis of B from radioactive and stable isotope tracers are compared. With radioisotope tracers, only a single quantity is detected, the amount of radioactivity in B. In contrast, isotopes of varying mass produce multiple mass isotopomers B that are detected using mass spectrometry. The analysis demonstrates that the rate of synthesis of B is identifiable from stable isotope data but not from radioisotope data. This results because the isotopomer distribution of B at any time after tracer addition is a function of only the multinomial distribution representing the synthesis of B from n molecules of A and two parameters representing the fractional fluxes of isotopically enriched molecules to the sampled compartment of B. The model considers the possibility that the sampled compartment of B may not reach isotopic steady state during the experiment. A graphical method for obtaining initial estimates of the two parameters is presented.
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Hungate, Bruce A., Rebecca L. Mau, Egbert Schwartz, J. Gregory Caporaso, Paul Dijkstra, Natasja van Gestel, Benjamin J. Koch, et al. "Quantitative Microbial Ecology through Stable Isotope Probing." Applied and Environmental Microbiology 81, no. 21 (August 21, 2015): 7570–81. http://dx.doi.org/10.1128/aem.02280-15.

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ABSTRACTBacteria grow and transform elements at different rates, and as yet, quantifying this variation in the environment is difficult. Determining isotope enrichment with fine taxonomic resolution after exposure to isotope tracers could help, but there are few suitable techniques. We propose a modification tostableisotopeprobing (SIP) that enables the isotopic composition of DNA from individual bacterial taxa after exposure to isotope tracers to be determined. In our modification, after isopycnic centrifugation, DNA is collected in multiple density fractions, and each fraction is sequenced separately. Taxon-specific density curves are produced for labeled and nonlabeled treatments, from which the shift in density for each individual taxon in response to isotope labeling is calculated. Expressing each taxon's density shift relative to that taxon's density measured without isotope enrichment accounts for the influence of nucleic acid composition on density and isolates the influence of isotope tracer assimilation. The shift in density translates quantitatively to isotopic enrichment. Because this revision to SIP allows quantitative measurements of isotope enrichment, we propose to call it quantitative stable isotope probing (qSIP). We demonstrated qSIP using soil incubations, in which soil bacteria exhibited strong taxonomic variations in18O and13C composition after exposure to [18O]water or [13C]glucose. The addition of glucose increased the assimilation of18O into DNA from [18O]water. However, the increase in18O assimilation was greater than expected based on utilization of glucose-derived carbon alone, because the addition of glucose indirectly stimulated bacteria to utilize other substrates for growth. This example illustrates the benefit of a quantitative approach to stable isotope probing.
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Jensen, Alexandria, William Ford, James Fox, and Admin Husic. "Improving In-Stream Nutrient Routines in Water Quality Models Using Stable Isotope Tracers: A Review and Synthesis." Transactions of the ASABE 61, no. 1 (2018): 139–57. http://dx.doi.org/10.13031/trans.12545.

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Abstract. Water quality models serve as an economically feasible alternative to quantify fluxes of nutrient pollution and to simulate effective mitigation strategies; however, their applicability is often questioned due to broad uncertainties in model structure and parameterization, leading to uncertain outputs. We argue that reduction of uncertainty is partially achieved by integrating stable isotope data streams within the water quality model architecture. This article outlines the use of stable isotopes as a response variable within water quality models to improve the model boundary conditions associated with nutrient source provenance, constrain model parameterization, and elucidate shortcomings in the model structure. To assist researchers in future modeling efforts, we provide an overview of stable isotope theory; review isotopic signatures and applications for relevant carbon, nitrogen, and phosphorus pools; identify biotic and abiotic processes that impact isotope transfer between pools; review existing models that have incorporated stable isotope signatures; and highlight recommendations based on synthesis of existing knowledge. Broadly, we find existing applications that use isotopes have high efficacy for reducing water quality model uncertainty. We make recommendations toward the future use of sediment stable isotope signatures, given their integrative capacity and practical analytical process. We also detail a method to incorporate stable isotopes into multi-objective modeling frameworks. Finally, we encourage watershed modelers to work closely with isotope geochemists to ensure proper integration of stable isotopes into in-stream nutrient fate and transport routines in water quality models. Keywords: Isotopes, Nutrients, Uncertainty analysis, Water quality modeling, Watershed.
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Ludvigson, Greg A., Aaron F. Diefendorf, Marina B. Suarez, Luis A. González, Megan C. Corcoran, Kristen Schlanser, Peter P. Flaig, et al. "Stable Isotope Tracers of Cretaceous Arctic Paleoprecipitation." Geosciences 12, no. 4 (March 23, 2022): 143. http://dx.doi.org/10.3390/geosciences12040143.

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We report estimated stable isotope compositions of depositional waters and paleoprecipitation from the Cretaceous Arctic to further elucidate the role of the global hydrologic cycle in sustaining polar warmth during that period. Estimates are based on new hydrogen isotopic analyses of n-alkane biomarkers extracted from Late Cretaceous and mid-Cretaceous terrestrial deposits in northern Alaska and the Canadian High Arctic. We integrate these new results with earlier published work on oxygen isotopic analyses of pedogenic siderites, dinosaurian tooth enamel phosphates, and pedogenic clay minerals from the same field areas. Average Late Cretaceous δD values of −143‰ VSMOW corresponded with average δ18O values of −24.1‰ VSMOW, and average mid-Cretaceous δD values of −106‰ VSMOW corresponded with average δ18O values of −22.1‰ VSMOW. The distributions of water isotope δD and δ18O values from Cretaceous Arctic deposits do not intersect with the Global Meteoric Water Line, suggesting an apparent deuterium excess ranging from about 40 to 60 per mil. We considered several possible explanations for these Cretaceous results including (1) mass-balance changes in zonal patterns of evaporation and precipitation at lower latitudes, (2) concentration of 2H in leaf tissue waters from continuous transpiration by coniferous paleofloras during the Arctic growing season, and (3) concentration of 2H in the groundwaters of methane-emitting Arctic soils.
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Coggan, Andrew R. "Use of stable isotopes to study carbohydrate and fat metabolism at the whole-body level." Proceedings of the Nutrition Society 58, no. 4 (November 1999): 953–61. http://dx.doi.org/10.1017/s0029665199001263.

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The present review discusses the advantages and limitations of using stable-isotope tracers to assess carbohydrate and fat metabolism at the whole-body level. One advantage of stable-(v. radioactive-) isotope tracers is the relative ease with which the location of a label within a molecule can be determined using selected-ion-monitoring GC-mass spectrometry (SIM-GC- MS). This technique minimizes potential problems due to label recycling, allows the use of multiple-labelled compounds simultaneously (e.g. to quantify glucose cycling), and perhaps most importantly, has led to the development of unique stable-isotope methods for, for example, quantifying gluconeogenesis. However, the limited sensitivity of SIM-GC-MS sometimes requires that relatively large amounts of a stable-isotope tracer be used, thus increasing cost and potentially altering metabolism. At least theoretically, stable- (or radioactive-) isotope tracers can also be used in conjunction with indirect calorimetry to estimate utilization of muscle glycogen or triacylglycerol stores, thus potentially circumventing the need to obtain muscle biopsies. These calculations, however, require certain critical assumptions, which if incorrect could lead to major errors in the values obtained. Despite such limitations, stable-isotope tracers provide a powerful and sometimes unique tool for investigating carbohydrate and fat metabolism at the whole-body level. With continuing advances in availability, instrumentation and methods, it is likely that stable-isotope tracers will become increasingly important in the immediate future.
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Argoud, G. M., D. S. Schade, and R. P. Eaton. "Underestimation of hepatic glucose production by radioactive and stable tracers." American Journal of Physiology-Endocrinology and Metabolism 252, no. 5 (May 1, 1987): E606—E615. http://dx.doi.org/10.1152/ajpendo.1987.252.5.e606.

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Although negative hepatic glucose production rates are physiologically impossible, they have been observed when hepatic glucose production is measured with the tracer-dilution technique during the hyperinsulinemic, euglycemic glucose clamp. Because hepatic glucose production is determined from the difference between tracer-derived glucose disposal and the known exogenous glucose infusion rate, the negative values for hepatic glucose production must result from an underestimation of glucose disposal by the tracer technique. In the current investigation, tracer-derived glucose disposal was measured in 25 subjects undergoing hyperinsulinemic, euglycemic clamps. Glucose disposal was measured with both radioactive and stable isotopes that utilize different methodologies, to determine whether discriminant metabolism of the isotopes versus methodological error leads to underestimation of tracer-derived glucose disposal. Both the radioactive and stable methodologies underestimated the exogenous glucose infusion rate during the hyperinsulinemic euglycemic clamp by 27 and 17%, respectively. Mean hepatic glucose production was -2.1 +/- 0.2 and -1.3 +/- 0.2 mg X kg-1 X min-1 as determined by the radioactive and stable isotope methodologies, respectively. Methodological error was an unlikely cause of this underestimation because it occurred with two different methodologies. The most likely explanation for underestimated rates of glucose disposal determined by the two types of isotope methodologies is discrepant metabolism of glucose tracers in comparison with unlabeled glucose.
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Jackisch, Dominik, Bi Xuan Yeo, Adam D. Switzer, Shaoneng He, Danica Linda M. Cantarero, Fernando P. Siringan, and Nathalie F. Goodkin. "Precipitation stable isotopic signatures of tropical cyclones in Metropolitan Manila, Philippines, show significant negative isotopic excursions." Natural Hazards and Earth System Sciences 22, no. 1 (January 28, 2022): 213–26. http://dx.doi.org/10.5194/nhess-22-213-2022.

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Abstract. Tropical cyclones have devastating impacts on the environment, economies, and societies and may intensify in the coming decades due to climate change. Stable water isotopes serve as tracers of the hydrological cycle, as isotope fractionation processes leave distinct precipitation isotopic signatures. Here we present a record of daily precipitation isotope measurements from March 2014 to October 2015 for Metropolitan Manila, a first-of-a-kind dataset for the Philippines and Southeast Asia. We show that precipitation isotopic variation at our study site is closely related to tropical cyclones. The most negative shift in δ18O values (−13.84 ‰) leading to a clear isotopic signal was caused by Typhoon Rammasun, which directly hit Metropolitan Manila. The average δ18O value of precipitation associated with tropical cyclones is −10.24 ‰, whereas the mean isotopic value for rainfall associated with non-cyclone events is −5.29 ‰. Further, the closer the storm track is to the sampling site, the more negative the isotopic values are, indicating that in situ isotope measurements can provide a direct linkage between isotopes and typhoon activities in the Philippines.
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Dissertations / Theses on the topic "Stable isotope tracers"

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North, Jessica C., and n/a. "Stable isotope tracers of landfill leachate impacts on aquatic systems." University of Otago. Department of Chemistry, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070504.144317.

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The present study aimed to determine whether stable isotope techniques can be universally applied to detect landfill leachate contamination in aquatic systems. Results of analysis of ��C in dissolved inorganic carbon ([delta]��C-DIC), deuterium and �⁸O in water ([delta]D-H₂O and [delta]�⁸O-H₂O), and �⁵N of dissolved inorganic nitrogen components ([delta]�⁵N-NH₄⁺ and [delta]�⁵N-NO₃⁻) were presented for leachate, surface, and ground water samples collected from seven landfills located throughout New Zealand between 2003 and 2006. The unique conditions within a landfill lead to measurable fractionations in the isotopic ratios of the products of degradation. Results of isotope and ancillary parameter analyses enabled the discernment of different types of leachate, resulting from different microbial processes within the landfill environment. The isotopic characterisation of leachate enabled improved interpretation of geochemical data from potentially impacted surface and ground waters, and provides useful insight to landfill development for landfill operators. A general isotopic fingerprint delineated by [delta]��C-DIC and [delta]D-H₂O values showed leachate to be isotopically distinct from uncontaminated surface and ground water for samples analysed in the present study. However, not all water samples identified as leachate-impacted via site-specific assessments exhibited isotopic values that overlapped with the general leachate fingerprint. This highlights the need to investigate each site individually, within the context of a possibly global leachate isotope signature. Site-specific investigations revealed the effectiveness of applying [delta]�⁸O-H₂O and [delta]�⁵N-NH₄⁺ or [delta]�⁵N-NO₃⁻, in addition to [delta]��C-DIC and [delta]D-H₂O analyses, to the detection of leachate impact on aquatic systems. Furthermore, ancillary parameters such as alkalinity and ammonium concentration enabled the construction of simple isotope mixing models for an estimate of the quantity of leachate contribution. Results of isotopic investigations of stream biota suggested potential for the development of bio-indicators to monitor leachate influence on aquatic ecosystems in landfill-associated streams. The present study demonstrated the probative power of stable isotope techniques applied to investigations of leachate impact on landfill-associated aquatic systems.
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Nilsson, Lino. "Nitrogen transformations at the Kiruna mine : The use of stable nitrogen isotopes to trace nitrogen-transforming processes." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-209419.

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Release of different nitrogen compounds can cause eutrophication in lakes and rivers whichcan lead to oxygen-free environments in bottom water and in the sediment and can in turnlead to fish-deaths. Ammonium can be toxic to biota and nitrate can in high concentrationeven be toxic to humans. WHO has released a limit for nitrate concentration in drinking waterof 10mg/l. The LKAB mine in Kiruna is the largest underground iron mine in the world and isprospecting, mining and refining iron ore, with an annual production of around 28 milliontons. Release of different nitrogen compounds as a result of the explosives used during themining operations has been a known problem for some time; however the processes affectingnitrogen during the water transport have never been fully investigated. The main objective of this MSc thesis is to determine if changes in nitrogen and oxygenisotope composition can be used as a tracer for nitrogen transformation processes in the minewater at LKABs underground mine in Kiruna. Water samples were collected at key points in the water transport system and were analyzedfor isotopic composition. Isotopic and chemical data revealed two different sources of nitrateand ammonium, undetonated explosives and leachate from waste rocks. Three differentnitrogen changing processes affecting concentration of nitrate and ammonium were found:ammonium volatilization, nitrification and sorption. It was not possible to quantify theseprocesses individually. No processes which decrease the nitrate concentration were found.
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Aravindhan, Karpagam Jucker Beat M. DiNardo N. John. "Assessing the effects of LXR agonists in cholesterol handling: stable isotope tracer studies /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/613.

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Benbow, Timothy J., and n/a. "Developing compound-specific stable isotope tools for monitoring landfill leachate." University of Otago. Department of Chemistry, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080314.111826.

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This thesis has developed a suite of compound specific stable isotope tools to monitor landfill leachate and identify the infiltration of leachate to ground water and surface water. These tools have the power to indicate the fractional contribution multiple discrete sources of pollution are making to a single location. This journey began by developing two solid phase extraction (SPE) methods to extract non-polar and polar organic compounds from leachate with minimal fractionation of hydrogen or carbon isotopes. Non-polar compounds were successfully extracted using ENV+ SPE cartridges and polar compounds were successfully extracted using Strata-X SPE cartridges. The isotopic fractionation of non-polar compounds during ENV+ extraction varied significantly (up to 245⁰/₀₀ and 1.8⁰/₀₀ for D and ��C respectively, when eluted with acetonitrile and ethyl acetate, as recommended by manufacturers) but the fractionation of compounds eluted with dichloromethane was negligible (less than instrumental precision). Polar compounds were eluted from Strata-X cartridges with negligible isotopic fractionation using methanol. The direct comparison of SPE and liquid-liquid extraction found SPE to extract slightly more compound from leachate then liquid-liquid extraction (especially for polar compounds) and the isotopic compositions of compounds did not change with extraction methods. These new analytical methods subsequently were used to determine the isotopic compositions of organic compounds dissolved in leachates from three New Zealand landfills. The molecular and isotopic signature of leachate varied significantly between landfills, indicating the isotopic fingerprint of organic compounds in leachate is unsuitable as a universal tracer of leachate. However, compounds such as terpien-4-ol, methylethylbenzene and juvabione maintained their isotopic composition over short geographical distance-indicating their potential as site-specific tracers of leachate. Organic compounds analysed on a transect across the landfill boundary indicated polar compounds were more mobile than semi-volatile compounds and possessed a more conservative isotopic composition. However, hexadecanoic acid extracted from leachate and ground water was highly depleted in ��C (-72 ⁰/₀₀ to -40⁰/₀₀), indicative of methanogenic and sulfate reducing bacteria. These bacteria only live in highly reducing environments such as leachate; therefore their presence in the pristine environment can potentially indicate the release of leachate from the landfill. The final experiments traced the uptake and utilisation of leachate by periphyton. The isotopic composition of bulk periphyton, fatty acids and phytol indicated that microbial assimilation and utilisation of nutrients is a complex process. Fatty acid biomarkers for green algae and diatoms showed signs of leachate derived nutrients, however the availability of nutrients (carbon, nitrogen, water and light) caused significant changes in metabolic processes and isotopic compositions. Under slow growing conditions, the [delta]��C composition of periphyton became enriched in ��C as solar irradiation levels decreased (including shading by detritus and periphyton), while the [delta]D composition of fatty acid was controlled by the internal recycling of hydrogen. This study indicated the power of compound specific isotope analysis as a tool to detect the release of landfill leachate from a landfill, especially at locations with multiple potential sources of contaminants, and provides a sound platform for future research.
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Lambertsson, Lars. "Mercury species transformations in marine and biological systems studied by isotope dilution mass spectrometry and stable isotope tracers." Doctoral thesis, Umeå : Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-467.

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Husic, Admin. "NUMERICAL MODELING AND ISOTOPE TRACERS TO INVESTIGATE KARST BIOGEOCHEMISTRY AND TRANSPORT PROCESSES." UKnowledge, 2018. https://uknowledge.uky.edu/ce_etds/70.

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This dissertation investigated the physical and biogeochemical processes affecting the source, fate, and transport of sediment, carbon, and nitrogen within a highly-coupled fluviokarst system. Elemental and isotopic datasets were collected at surface and subsurface locations for both dissolved and particulate contaminant phases, new methodology regarding data collection was presented to the karst research community, an in-cave sediment transport model coupling physical transport with elemental and isotopic mass balances of carbon and nitrogen was formulated, pathway and process control on nitrate leaching from agricultural karst watersheds was assessed, and nitrate mobilization and fractionation were modeled using high frequency storm sampling and long-term low-flow sampling. Data and modeling results indicate that phreatic karst conduits are transport-limited during hydrologic events and experience subsurface deposition of labile, storm-injected sediment which is subsequently decomposed by heterotrophic bacteria. An estimated 30% of the organic carbon associated with sediment is decomposed during transport in the subsurface karst. Concentrations of nitrate in subsurface waters are consistently 50% greater than surface inputs suggesting an additional source of subsurface nitrate. Further modeling of nitrate leaching indicates that quick-flow water sources dilute nitrate concentrations and slow-flow (epikarst and phreatic) sources account for approximately 90% of downstream nitrate delivery. Field sampling of extreme events highlights the physical transport and delayed release of high nitrate concentrations by intermediate karst pathways, which is likely associated with a transition from epikarst to soil drainage during storm recession. Modeling of sediment carbon and nitrogen within the karst SFGL supports the idea that the cave sediment bed experiences hot spots and hot moments of biogeochemical activity. Sediment nitrogen tracing data show a significant increase in δ15NSed at the spring outlet relative to karst inputs indicating the potential for isotope fractionation effects during dissolved N uptake by cave biota. Dissolved nitrogen stable isotopic composition shows a significant downstream decrease in δ15NNO3 within the conduit, likely associated with nitrification. Data and modeling results of sediment, carbon, and nitrogen emphasize the role of multiple pathways, turbulent transport, and in-conduit transformations in controlling contaminant flux from karst watersheds.
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Crane, Justin D. "The muscle specific protein synthesis response to acute running exercise utilizing multiple stable isotope tracers." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1398709.

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The purpose of this study was to compare the anabolic response to acute running exercise in two different leg muscles in endurance-trained men using two different stable isotope tracers. 6 male subjects (26±2 yr; V02max 63±2 ml•kg-' •min-') performed a 45 min treadmill run at 77±1 % intensity. Infusions of d3-leucine and d5-phenylalanine were used to measure mixed muscle FSR at rest and 24 hr post-exercise. An additional infusion of 10% amino acid solution was added to the post-exercise infusion to maximize the muscle anabolic response. Muscle biopsies were obtained from the vastus lateralis (VL) and soleus (SOL) at 2 and 6 hr of the infusion for the measurement of isotope incorporation. Additional muscle biopsies were obtained prior to and 4 hr post-exercise for determination of muscle glycogen use. At rest FSR was similar between the VL and SOL using either tracer (p>0.05). At 24 hr post-exercise FSR was elevated in both muscles, independent of the tracer used (p<0.05). Muscle glycogen was decreased to the same extent in both muscles by -31% at 4 hr post-exercise (p<0.05). These data suggest that the VL and SOL muscles are both stimulated similarly during 45 min of level grade running. Additionally, both muscles respond similarly 24 hr post-exercise, independent of the tracer used for the determination of protein synthesis.
School of Physical Education, Sport, and Exercise Science
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Herzka, Sharon Zinah. "Characterization of the recruitment patterns of red drum (Sciaenops ocellatus) larvae to estuarine nursery habitat using stable isotopes as natural tracers of settlement /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.

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Buchheister, Andre. "Stable Isotope Dynamics in Summer Flounder Tissues, with Application to Dietary Assessments in Chesapeake Bay." W&M ScholarWorks, 2008. http://www.vims.edu/library/Theses/Buchheister08.pdf.

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Turki, Abrar Mohammed. "Application of stable isotope tracers to examine phenylalanine metabolism and protein requirements in children with phenylketonuria (pku)." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53095.

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Phenylketonuria (PKU) is an inherited inborn error of phenylalanine (PHE) metabolism caused by deficiency of hepatic enzyme phenylalanine hydroxylase (PAH). Therefore, PHE accumulates in plasma leading to mental retardation and developmental delay. Kuvan® (Sapropterin dihydrochloride), a synthetic form of tetrahydrobiopterin (BH₄), has been shown to reduce plasma PHE levels in PKU, but not all patients respond to sapropterin treatment. The major mode of treatment remains nutritional management with dietary restriction of PHE and provision of sufficient protein. The dietary protein requirement in children with PKU remains unknown. Therefore the objectives of the current thesis were: 1) to identify sapropterin responsiveness in PKU children using a minimally invasive L-[1-¹³C] phenylalanine breath test (¹³C-PBT), and 2) to determine protein requirements in PKU children using the indicator amino acid oxidation (IAAO) technique. Experiment 1- Nine children with PKU (5-18y) underwent ¹³C-PBT tracer protocols twice, once before and once after 1-2 weeks of sapropterin therapy. ¹³CO₂ was measured using isotope ratio mass spectrometer (IRMS). The study protocol was tested in healthy children (n= 6) as proof of principle. Experiment 2- Four PKU children (5-18y) were recruited to participate in test protein intakes (ranging from deficiency to excess 0.2 – 3.2 g/kg/d) with the IAAO protocol using L-[1-¹³C] leucine, followed by collection of breath and urine samples over 8 hours. Results 1- ¹³CO₂ productions in all children with PKU pre-sapropterin treatment were low, except in one child (PKU04). Five children with PKU showed a significantly higher peak enrichment after sapropterin treatment at 20min. Three PKU children had no change in ¹³CO₂ production post sapropterin therapy. Results 2- The mean protein requirement, identified using 2-phase linear regression analysis was determined to be 1.85 g/kg/d. This result is significantly higher than the most recent PKU recommendations (2014) (1.14 – 1.33g/kg/d, based on 120-140% above current recommended dietary allowance RDA). These findings show that the ¹³C-PBT can be a minimally invasive method to examine in vivo PHE metabolism in PKU children responsive to sapropterin therapy. Also, current recommendations for optimal protein intake may be underestimated.
Land and Food Systems, Faculty of
Graduate
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Books on the topic "Stable isotope tracers"

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1938-, Coleman David C., and Fry Brian, eds. Carbon isotope techniques. San Diego: Academic Press, 1991.

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Introduction to isotope hydrology: Stable and radioactive isotopes of hydrogen, oxygen and carbon. London: Taylor & Francis, 2006.

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Izbicki, John A. Source, movement, and age of ground water in a coastal California aquifer. [Washington, D.C.?]: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Krumbiegel, Peter. Stable isotope pharmaceuticals: For clinical research and diagnosis. Jena: Gustav Fischer Verlag, 1991.

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Jornadas sobre "Nuevas Técnicas Metodológicas Aplicadas al Estudio de los Sistemas Ambientales: los Isótopos Estables" (2005 Universidad Autónoma de Madrid). Técnicas y aplicaciones multidisciplinares de los isótopos ambientales. Madrid: Servicio de Publicaciones de la Universidad Autónoma de Madrid, 2008.

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Madrid), Jornadas sobre "Nuevas Técnicas Metodológicas Aplicadas al Estudio de los Sistemas Ambientales: los Isótopos Estables" (2005 Universidad Autónoma de. Técnicas y aplicaciones multidisciplinares de los isótopos ambientales. Madrid: Servicio de Publicaciones de la Universidad Autónoma de Madrid, 2008.

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R, Wolfe Robert, ed. Radioactive and stable isotope tracers in biomedicine: Principles and practice of kinetic analysis. New York: Wiley-Liss, 1992.

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Segschneider, Hans-Josef. Untersuchungen zur Aufnahme und zum Einbau von anthropogenen Stickoxiden (NOx) durch Sonnenblumen und Mais mittels 15N-Isotopen-Markierung. Jülich, Bundesrepublik Deutschland: Forschungszentrum Jülich GmbH, Zentralbibliothek, 1994.

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Roger, Whitehead, Prentice Ann, and Bristol-Myers Squibb/Mead Johnson Symposium on Nutrition Research (9th : 1989 : Robinson College), eds. New techniques in nutritional research. San Diego: Academic Press, 1991.

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Schimel, David Steven. Theory and application of tracers. San Diego: Academic Press, 1993.

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Book chapters on the topic "Stable isotope tracers"

1

Fry, Brian. "Using Stable Isotope Tracers." In Stable Isotope Ecology, 40–75. New York, NY: Springer New York, 2006. http://dx.doi.org/10.1007/0-387-33745-8_3.

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Violante, Sara, Mirela Berisa, Tiffany H. Thomas, and Justin R. Cross. "Stable Isotope Tracers for Metabolic Pathway Analysis." In High-Throughput Metabolomics, 269–83. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9236-2_17.

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Coplen, Tyler B., Andrew L. Herczeg, and Chris Barnes. "Isotope Engineering—Using Stable Isotopes of the Water Molecule to Solve Practical Problems." In Environmental Tracers in Subsurface Hydrology, 79–110. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4557-6_3.

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Schell, D. M., and P. J. Ziemann. "Natural Carbon Isotope Tracers in Arctic Aquatic Food Webs." In Stable Isotopes in Ecological Research, 230–51. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4612-3498-2_13.

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Schwarcz, H. P., and M. J. Schoeninger. "Stable Isotopes of Carbon and Nitrogen as Tracers for Paleo-Diet Reconstruction." In Advances in Isotope Geochemistry, 725–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_34.

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Bullen, Thomas D. "Stable Isotopes of Transition and Post-Transition Metals as Tracers in Environmental Studies." In Advances in Isotope Geochemistry, 177–203. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_10.

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Johnson, Thomas M. "Stable Isotopes of Cr and Se as Tracers of Redox Processes in Earth Surface Environments." In Advances in Isotope Geochemistry, 155–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_9.

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Westera, Liset, Yan Zhang, Kiki Tesselaar, José A. M. Borghans, and Derek C. Macallan. "Quantitating Lymphocyte Homeostasis In Vivo in Humans Using Stable Isotope Tracers." In Methods in Molecular Biology, 107–31. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-290-2_10.

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Amundson, Ronald, and W. Troy Baisden. "Stable Isotope Tracers and Mathematical Models in Soil Organic Matter Studies." In Methods in Ecosystem Science, 117–37. New York, NY: Springer New York, 2000. http://dx.doi.org/10.1007/978-1-4612-1224-9_9.

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Vetter, W. "Utility of Stable Isotopes of Hydrogen and Carbon as Tracers of POPs and Related Polyhalogenated Compounds in the Environment." In Advances in Isotope Geochemistry, 679–703. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_32.

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Conference papers on the topic "Stable isotope tracers"

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Sun, Ramon C., Marc O. Warmoes, Ye Yang, Pan Deng, Qiushi Sun, Andrew N. Lane, Richard M. Higashi, and Teresa W.-M. Fan. "Abstract 2502: Liquid diet introduction of tracers into mice for stable isotope-resolved metabolomics (SIRM) investigations." In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-2502.

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Swearingen, Jerry, and Yani Araujo De Itriago. "Advanced Analytical Tools for Fingerprinting, Production Allocation, & Improved/Enhanced Oil Recovery Monitoring." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210060-ms.

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Abstract Demands are being placed on service companies to provide non-evasive analytical solutions that measure the contribution of individual hydrocarbon streams in a commingled system. This often involves being able to differentiate fluids which have similar compositions. An advanced analytical workflow has been developed which includes chromatographic techniques along with a suite of stable isotope ratio analyses that look at unique Natural Tracers/Markers in individual hydrocarbon or brine streams. This paper will look at how the Natural Tracer methodology can be applied to fingerprinting, production allocation and IOR/EOR projects. A variety of laboratory-based techniques were used to evaluate end member fluids, commingled fluids, and various synthetic blends. Gaseous streams were analyzed using compound specific stable isotope ratio mass spectrometry systems (CS-IRMS) looking at carbon and hydrogen isotopes of the carbon dioxide, methane, ethane, etc. present. Aqueous streams were analyzed using a combination of conventional physiochemical (complete water) and water oxygen and hydrogen stable isotope analysis. Liquid hydrocarbon systems were assessed using conventional high-resolution gas chromatography and 2-dimentional gas chromatography (GCxGC). Analysis of the data includes simple plots to visualize differences between fluid sources and a linear regression analysis to look at the mixing relationships between synthetic blends and commingled field samples. The advanced analytical workflow allowed for the allocation determination of hydrocarbon systems with both similar and contrasting compositions. The GCxGC method, for hydrocarbon liquids, allows for a higher resolution separation where a single peak using conventional gas chromatography can be composed of multiple types of compounds. In this instance the conventional GC and GCxGC yielded comparable allocation results. For gas phase allocation, using carbon and hydrogen isotope ratios (δ13C and δ2H) of methane and ethane yielded linear mixing relationships in the two-production systems that were analyzed. Allocation values were successfully calculated for these binary systems with an outlying datapoint resulting in the client initiating an investigation to confirm flow meter readings. For an IOR/EOR application, the δ13C of methane show sufficient contrast between injected and produced gases that were sampled from a variety of wells. In this instance the gas molar compositions were similar so the only means to identify injection gas breakthrough in producing wells was by the CS-IRMS analysis technique. Complete physiochemical and water isotope ratio (δ18O and δ2H) analysis also show contrasting signatures between injection and produced water. An advanced analytic workflow was developed to incorporate commercially available, non-evasive techniques to production allocation and IOR/EOR projects. For production allocation, this technique will not replace traditional metering but can be used as a tool to identify problems with the metering/monitoring systems in the field.
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Sánchez-Murillo, Ricardo. "Tracer hydrology of the data-scarce and heterogeneous Central American Isthmus." In I Congreso Internacional de Ciencias Exactas y Naturales. Universidad Nacional, 2019. http://dx.doi.org/10.15359/cicen.1.36.

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Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This chapter uses stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial-temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water-groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the Mid-Summer Drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by a) depleted recharge in highland areas (72.3%), b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m a.s.l. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus.
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Moxley, Nathan, C. Kent Keller, Richard M. Conrey, and James L. Osiensky. "STABLE ISOTOPES OF HYDROGEN AND OXYGEN: HYDROLOGIC TRACERS OF AQUIFER RECHARGE." In 68th Annual Rocky Mountain GSA Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016rm-276104.

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Aldahik, A. "Trace Origin of Gas Leakage behind Casing Using Stable Isotope Geochemistry." In EAGE Workshop on Petroleum Geochemistry in Operations and Production. Netherlands: EAGE Publications BV, 2016. http://dx.doi.org/10.3997/2214-4609.201602333.

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Doctor, Daniel. "SOME CONSIDERATIONS ON THE USE OF STABLE CARBON ISOTOPES AS TRACERS IN KARST AQUIFERS." In GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-367648.

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Magdas, D. A., A. Dehelean, R. Puscas, G. Cristea, F. Tusa, C. Voica, and Mihaela D. Lazar. "The quality control of fruit juices by using the stable isotope ratios and trace metal elements concentrations." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2011). AIP, 2012. http://dx.doi.org/10.1063/1.3681996.

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Burton, Kevin, Corey Archer, Philip Pogge von Strandmann, Alex McCoy-West, and Sigurdur Gislason. "Elemental release from estuarine particulates traced using iron and neodymium stable isotopes." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.7993.

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Zimmermann, Tristan, Ole Klein, Anna Reese, Fwziah Mohamed, Michael Wieser, Johanna Irrgeher, and Daniel Pröfrock. "“Non-Traditional” Stable Isotope Analysis as Tracer so Identify Sources and Sinks of Inorganic Contaminants in Riverine Environments." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.3228.

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Nitzsche, Kai, Toshihiro Yoshimura, Naoto Ishikawa, Hiroto Kajita, Nanako Ogawa, Katz Suzuki, and Naohiko Ohkouchi. "Zinc stable isotopes as tracers for Zn pollution in sediment cores from historically polluted Lake Biwa and Osaka Bay." In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.10648.

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Reports on the topic "Stable isotope tracers"

1

Schroeder, Gerald, D. Homer Buck, and Courtney Coleman. Stable Isotope Ratio as Naturally Occurring Tracers in the Aquaculture Food Web. United States Department of Agriculture, June 1986. http://dx.doi.org/10.32747/1986.7598895.bard.

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Jacques, I. J., A. J. Anderson, and S. G. Nielsen. The geochemistry of thallium and its isotopes in rare-element pegmatites. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328983.

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The Tl isotopic and trace element composition of K-feldspar, mica, pollucite and pyrite from 13 niobium-yttrium-fluorine (NYF)-type and 14 lithium-cesium-tantalum (LCT)-type rare-element pegmatites was investigated. In general, the epsilon-205Tl values for K-feldspar in NYF- and LCT-type pegmatites increases with increasing magmatic fractionation. Both NYF and LCT pegmatites display a wide range in epsilon-205Tl (-4.25 to 9.41), which complicates attempts to characterize source reservoirs. We suggest 205Tl-enrichment during pegmatite crystallization occurs as Tl partitions between the residual melt and a coexisting aqueous fluid or flux-rich silicate liquid. Preferential association of 205Tl with Cl in the immiscible aqueous fluid may influence the isotopic character of the growing pegmatite minerals. Subsolidus alteration of K-feldspar by aqueous fluids, as indicated by the redistribution of Cs in K-feldspar, resulted in epsilon-205Tl values below the crustal average (-2.0 epsilon-205Tl). Such low epsilon-205Tl values in K-feldspar is attributed to preferential removal and transport of 205Tl by Cl-bearing fluids during dissolution and reprecipitation. The combination of thallium isotope and trace element data may be used to examine late-stage processes related to rare-element mineralization in some pegmatites. High epsilon-205Tl and Ga in late-stage muscovite appears to be a favorable indicator of rare-element enrichment LCT pegmatites and may be a useful exploration vector.
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Luong, Elise. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems. Office of Scientific and Technical Information (OSTI), May 1999. http://dx.doi.org/10.2172/355038.

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Neyedley, K., J. J. Hanley, Z. Zajacz, and M. Fayek. Accessory mineral thermobarometry, trace element chemistry, and stable O isotope systematics, Mooshla Intrusive Complex (MIC), Doyon-Bousquet-LaRonde mining camp, Abitibi greenstone belt, Québec. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328986.

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The Mooshla Intrusive Complex (MIC) is an Archean polyphase magmatic body located in the Doyon-Bousquet-LaRonde (DBL) mining camp of the Abitibi greenstone belt, Québec, that is spatially associated with numerous gold (Au)-rich VMS, epizonal 'intrusion-related' Au-Cu vein systems, and shear zone-hosted (orogenic?) Au deposits. To elucidate the P-T conditions of crystallization, and oxidation state of the MIC magmas, accessory minerals (zircon, rutile, titanite) have been characterized using a variety of analytical techniques (e.g., trace element thermobarometry). The resulting trace element and oxythermobarometric database for accessory minerals in the MIC represents the first examination of such parameters in an Archean magmatic complex in a world-class mineralized district. Mineral thermobarometry yields P-T constraints on accessory mineral crystallization consistent with the expected conditions of tonalite-trondhjemite-granite (TTG) magma genesis, well above peak metamorphic conditions in the DBL camp. Together with textural observations, and mineral trace element data, the P-T estimates reassert that the studied minerals are of magmatic origin and not a product of metamorphism. Oxygen fugacity constraints indicate that while the magmas are relatively oxidizing (as indicated by the presence of magmatic epidote, titanite, and anhydrite), zircon trace element systematics indicate that the magmas were not as oxidized as arc magmas in younger (post-Archean) porphyry environments. The data presented provides first constraints on the depth and other conditions of melt generation and crystallization of the MIC. The P-T estimates and qualitative fO2 constraints have significant implications for the overall model for formation (crystallization, emplacement) of the MIC and potentially related mineral deposits.
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Marks, N. E., L. E. Borg, G. R. Eppich, A. M. Gaffney, V. G. Genneti, I. D. Hutcheon, M. J. Kristo, et al. Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate. Office of Scientific and Technical Information (OSTI), July 2015. http://dx.doi.org/10.2172/1243009.

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Reid, M. S., X. Wang, N. Utting, and C. Jiang. Comparison of water chemistry of hydraulic-fracturing flowback water from two geological locations at the Duvernay Formation, Alberta, Canada. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/329276.

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We analyzed and compared the water chemistry between 17 Fox Creek region samples, each from a different well, and 23 Three Hills region samples from a single well. Overall, the two regions were similar in chemical composition but showed small differences in some lower abundance dissolved elements. Additionally, we investigated changes in water chemistry of FPW over time from a single well. The majority of water quality parameters and water chemistry remained constant over the 7-month sampling time. Major ion chemistry showed increasing concentrations of Ca and Mg, and a decreasing concentration of SO4. Several trace elements also showed small trends of both increasing and decreasing concentrations over time. There was a strong correlation between Ca and Mg concentrations in both the Fox Creek region samples and Three Hills region samples, which is an indication of the mixing of formation water. However, the correlation between B and Sr was different among two region samples, which is likely due to the delayed mixing of formation water with the fracturing fluids during the flowback at different time periods of post fracturing. Likewise, Fox Creek region samples showed correlations between concentrations of Cl and Ca, Na and Ca, and Na and Mg, but these correlations were not seen in the Three Hills region samples. Geochemical modeling demonstrates that there are potential scales formed in the flowback water, but most of the minerals are still in the dissolution state in the formation. Stable isotopic analysis confirmed the mixing of injection water and the formation water.
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Neyedley, K., J. J. Hanley, P. Mercier-Langevin, and M. Fayek. Ore mineralogy, pyrite chemistry, and S isotope systematics of magmatic-hydrothermal Au mineralization associated with the Mooshla Intrusive Complex (MIC), Doyon-Bousquet-LaRonde mining camp, Abitibi greenstone belt, Québec. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328985.

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The Mooshla Intrusive Complex (MIC) is an Archean polyphase magmatic body located in the Doyon-Bousquet-LaRonde (DBL) mining camp of the Abitibi greenstone belt, Québec. The MIC is spatially associated with numerous gold (Au)-rich VMS, epizonal 'intrusion-related' Au-Cu vein systems, and shear zone-hosted (orogenic?) Au deposits. To elucidate genetic links between deposits and the MIC, mineralized samples from two of the epizonal 'intrusion-related' Au-Cu vein systems (Doyon and Grand Duc Au-Cu) have been characterized using a variety of analytical techniques. Preliminary results indicate gold (as electrum) from both deposits occurs relatively late in the systems as it is primarily observed along fractures in pyrite and gangue minerals. At Grand Duc gold appears to have formed syn- to post-crystallization relative to base metal sulphides (e.g. chalcopyrite, sphalerite, pyrrhotite), whereas base metal sulphides at Doyon are relatively rare. The accessory ore mineral assemblage at Doyon is relatively simple compared to Grand Duc, consisting of petzite (Ag3AuTe2), calaverite (AuTe2), and hessite (Ag2Te), while accessory ore minerals at Grand Duc are comprised of tellurobismuthite (Bi2Te3), volynskite (AgBiTe2), native Te, tsumoite (BiTe) or tetradymite (Bi2Te2S), altaite (PbTe), petzite, calaverite, and hessite. Pyrite trace element distribution maps from representative pyrite grains from Doyon and Grand Duc were collected and confirm petrographic observations that Au occurs relatively late. Pyrite from Doyon appears to have been initially trace-element poor, then became enriched in As, followed by the ore metal stage consisting of Au-Ag-Te-Bi-Pb-Cu enrichment and lastly a Co-Ni-Se(?) stage enrichment. Grand Duc pyrite is more complex with initial enrichments in Co-Se-As (Stage 1) followed by an increase in As-Co(?) concentrations (Stage 2). The ore metal stage (Stage 3) is indicated by another increase in As coupled with Au-Ag-Bi-Te-Sb-Pb-Ni-Cu-Zn-Sn-Cd-In enrichment. The final stage of pyrite growth (Stage 4) is represented by the same element assemblage as Stage 3 but at lower concentrations. Preliminary sulphur isotope data from Grand Duc indicates pyrite, pyrrhotite, and chalcopyrite all have similar delta-34S values (~1.5 � 1 permille) with no core-to-rim variations. Pyrite from Doyon has slightly higher delta-34S values (~2.5 � 1 permille) compared to Grand Duc but similarly does not show much core-to-rim variation. At Grand Duc, the occurrence of Au concentrating along the rim of pyrite grains and associated with an enrichment in As and other metals (Sb-Ag-Bi-Te) shares similarities with porphyry and epithermal deposits, and the overall metal association of Au with Te and Bi is a hallmark of other intrusion-related gold systems. The occurrence of the ore metal-rich rims on pyrite from Grand Duc could be related to fluid boiling which results in the destabilization of gold-bearing aqueous complexes. Pyrite from Doyon does not show this inferred boiling texture but shares characteristics of dissolution-reprecipitation processes, where metals in the pyrite lattice are dissolved and then reconcentrated into discrete mineral phases that commonly precipitate in voids and fractures created during pyrite dissolution.
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Shenker, Moshe, Paul R. Bloom, Abraham Shaviv, Adina Paytan, Barbara J. Cade-Menun, Yona Chen, and Jorge Tarchitzky. Fate of Phosphorus Originated from Treated Wastewater and Biosolids in Soils: Speciation, Transport, and Accumulation. United States Department of Agriculture, June 2011. http://dx.doi.org/10.32747/2011.7697103.bard.

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Beneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levelsBeneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levels that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction.
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Use of stable carbon and nitrogen isotopes to trace the larval striped bass food chain in the Sacramento-San Joaquin Estuary, California, April to September 1985. US Geological Survey, 1989. http://dx.doi.org/10.3133/wri884164.

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