keyword
MENU ▼
Read by QxMD icon Read
search

isotopic tracer method

keyword
https://www.readbyqxmd.com/read/28213127/quantitation-of-lead-210-210-pb-using-lead-203-203-pb-as-a-massless-yield-tracer
#1
D May, A N Nelson, M K Schultz
Determination of Pb-210 ((210)Pb) in aqueous solution is a common radioanalytical challenge in environmental science. Widely used methods for undertaking these analyses (e.g., ASTM D7535) rely on the use of stable lead (Pb) as a yield tracer that takes into account losses of (210)Pb that inevitably occur during elemental/radiochemical separations of the procedures. Although effective, these methods introduce technical challenges that can be difficult to track and potentially introduce uncertainty that can be difficult to quantify...
February 14, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28196754/determination-of-groundwater-recharge-mechanism-in-the-deep-loessial-unsaturated-zone-by-environmental-tracers
#2
Zhi Li, Xi Chen, Wenzhao Liu, Bingcheng Si
Studying the groundwater recharge mechanism in regions with thick unsaturated zone can greatly improve our understanding of hydrological processes since these regions have complex groundwater processes. This study attempted to discuss the groundwater recharge in a region covered by loess over 130m deep in China's Loess Plateau. The water stable isotope, tritium and chloride in precipitation, groundwater and soil water were determined and used as inputs of mass balance methods. The tracer technique is found to be applicable and effective this region with thick unsaturated zone...
February 10, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28195703/mass-spectrometric-determination-of-uranium-and-thorium-in-high-radiopurity-polymers-using-ultra-low-background-electroformed-copper-crucibles-for-dry-ashing
#3
Isaac J Arnquist, Eric W Hoppe, Mary Bliss, Jay W Grate
A rapid new method for determining the U and Th mass concentrations in high radiopurity plastics is described, consisting of 1) dry ashing the plastic sample and tracers in low mass crucibles made of ultra low background electroformed copper (ULB EF-Cu) foil cut and folded into boats, 2) dissolving both the ash and the boat in acid, 3) performing a column separation to remove copper, and 4) determining the elements of interest by isotope dilution mass spectrometry. This method was demonstrated on both unfluorinated and fluorinated plastics, demonstrating high tracer recoveries and detection limits to pg/g (i...
February 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192957/integrated-extraction-chromatographic-separation-of-the-lithophile-elements-involved-in-long-lived-radiogenic-isotope-systems-rb-sr-u-th-pb-sm-nd-la-ce-and-lu-hf-useful-in-geochemical-and-environmental-sciences
#4
Christian Pin, Abdelmouhcine Gannoun
A fast and efficient sample preparation method in view of isotope ratio measurements is described, allowing the separation of 11 elements involved, either as "parent" or as "daughter" isotopes, in six radiogenic isotope systems used as chronometers and tracers in earth, planetary, and environmental sciences. The protocol is based on small extraction chromatographic columns, used either alone or in tandem, through which a single nitric acid solution is passed, without any intervening evaporation step. The columns use commercially available extraction resins (Sr resin, TRU resin, Ln resin, RE resin, and again Ln resin for isolating Sr and Pb, LREE then La-Ce-Nd-Sm, Lu(Yb), and Hf, Th, and U, respectively) along with an additional, in-house prepared resin for separating Rb...
February 9, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28168704/positron-emission-tomography-with-additional-%C3%AE-ray-detectors-for-multiple-tracer-imaging
#5
Tomonori Fukuchi, Takashi Okauchi, Mika Shigeta, Seiichi Yamamoto, Yasuyoshi Watanabe, Shuichi Enomoto
PURPOSE: Positron emission tomography (PET) is a useful imaging modality that quantifies the physiological distributions of radiolabeled tracers in vivo in humans and animals. However, this technique is unsuitable for multiple-tracer imaging because the annihilation photons used for PET imaging have a fixed energy regardless of the selection of the radionuclide tracer. This study developed a multi-isotope PET (MI-PET) system and evaluated its imaging performance. METHODS: Our MI-PET system is composed of a PET system and additional γ-ray detectors...
February 7, 2017: Medical Physics
https://www.readbyqxmd.com/read/28161269/the-simultaneous-uptake-of-dietary-and-waterborne-cd-in-gastrointestinal-tracts-of-marine-yellowstripe-goby-mugilogobius-chulae
#6
Zhiqiang Guo, Na Gao, Yun Wu, Li Zhang
Aquatic animals under waterborne metal exposure are also very likely exposed to elevated dietary metals. This study quantified the simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts (GT) of marine yellowstripe goby using a dual stable isotope tracer method. The Cd spiked diet (10-100 μg g(-1), (111)Cd as tracers) were fed to the fish as a single meal, and then the fish were exposed to waterborne Cd (0-500 μg L(-1), (113)Cd as tracers) for 48 h, during which the time-course uptake of Cd in the stomach and intestine was determined...
February 1, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28158972/midcor-an-r-program-for-deciphering-mass-interferences-in-mass-spectra-of-metabolites-enriched-in-stable-isotopes
#7
Vitaly A Selivanov, Adrián Benito, Anibal Miranda, Esther Aguilar, Ibrahim Halil Polat, Josep J Centelles, Anusha Jayaraman, Paul W N Lee, Silvia Marin, Marta Cascante
BACKGROUND: Tracing stable isotopes, such as (13)C using various mass spectrometry (MS) methods provides a valuable information necessary for the study of biochemical processes in cells. However, extracting such information requires special care, such as a correction for naturally occurring isotopes, or overlapping mass spectra of various components of the cell culture medium. Developing a method for a correction of overlapping peaks is the primary objective of this study. RESULTS: Our computer program-MIDcor (free at https://github...
February 3, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28089618/24-hour-protein-arginine-and-citrulline-metabolism-in-fed-critically-ill-children-a-stable-isotope-tracer-study
#8
Carlijn T I de Betue, Xiomara C Garcia Casal, Dick A van Waardenburg, Stephen M Schexnayder, Koen F M Joosten, Nicolaas E P Deutz, Marielle P K J Engelen
BACKGROUND & AIMS: The reference method to study protein and arginine metabolism in critically ill children is measuring plasma amino acid appearances with stable isotopes during a short (4-8 h) time period and extrapolate results to 24-h. However, 24-h measurements may be variable due to critical illness related factors and a circadian rhythm could be present. Since only short duration stable isotope studies in critically ill children have been conducted before, the aim of this study was to investigate 24-h appearance of specific amino acids representing protein and arginine metabolism, with stable isotope techniques in continuously fed critically ill children...
January 4, 2017: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
https://www.readbyqxmd.com/read/28029480/sediment-source-identification-and-load-prediction-in-a-mixed-use-piedmont-watershed-south-carolina
#9
Kerry McCarney-Castle, Tristan M Childress, Christian R Heaton
Many streams in the Piedmont region of the southeastern United States transport a disproportionately large amount of suspended sediment in response to moderately increased streamflows. Transport and deposition of excess sediment affect the stability of the channel and the health of the biological community; therefore, identifying the main source(s) of sediment and assessing the relationships between source, transport, and streamflow are critical to aquatic life and habitat management, dynamic equilibrium preservation, and development of feasible mitigation scenarios...
October 28, 2016: Journal of Environmental Management
https://www.readbyqxmd.com/read/27989585/the-importance-of-accurately-correcting-for-the-natural-abundance-of-stable-isotopes
#10
REVIEW
Firas S Midani, Michelle L Wynn, Santiago Schnell
The use of isotopically labeled tracer substrates is an experimental approach for measuring in vivo and in vitro intracellular metabolic dynamics. Stable isotopes that alter the mass but not the chemical behavior of a molecule are commonly used in isotope tracer studies. Because stable isotopes of some atoms naturally occur at non-negligible abundances, it is important to account for the natural abundance of these isotopes when analyzing data from isotope labeling experiments. Specifically, a distinction must be made between isotopes introduced experimentally via an isotopically labeled tracer and the isotopes naturally present at the start of an experiment...
March 1, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/27923571/a-simple-dried-blood-spot-method-for-in-vivo-measurement-of-ureagenesis-by-gas-chromatography-mass-spectrometry-using-stable-isotopes
#11
Gabriella Allegri, Sereina Deplazes, Hiu Man Grisch-Chan, Déborah Mathis, Ralph Fingerhut, Johannes Häberle, Beat Thöny
BACKGROUND: Clinical management of inherited or acquired hyperammonemia depends mainly on the plasma ammonia level which is not a reliable indicator of urea cycle function as its concentrations largely fluctuate. The gold standard to assess ureagenesis in vivo is the use of stable isotopes. METHODS: Here we developed and validated a simplified in vivo method with [(15)N]ammonium chloride ([(15)N]H4Cl) as a tracer. Non-labeled and [(15)N]urea were quantified by GC-MS after extraction and silylation...
January 2017: Clinica Chimica Acta; International Journal of Clinical Chemistry
https://www.readbyqxmd.com/read/27906461/measurement-of-intestinal-and-peripheral-cholesterol-fluxes-by-a-dual-tracer-balance-method
#12
Onne A H O Ronda, Theo H van Dijk, H J Verkade, Albert K Groen
Long-term elevated plasma cholesterol levels put individuals at risk for developing atherosclerosis. Plasma cholesterol levels are determined by the balance between cholesterol input and output fluxes. Here we describe in detail the methodology to determine the different cholesterol fluxes in mice. The percentage of absorbed cholesterol is calculated from a stable isotope-based double-label method. Cholesterol synthesis is calculated from MIDA after (13) C-acetate enrichment. Cholesterol is removed from the body via the feces...
December 1, 2016: Current Protocols in Mouse Biology
https://www.readbyqxmd.com/read/27896775/uplc-ms-ms-determination-of-deuterated-25-hydroxyvitamin-d-d3-25ohd3-and-other-vitamin-d-metabolites-for-the-measurement-of-25ohd-half-life
#13
Shima Assar, Inez Schoenmakers, Albert Koulman, Ann Prentice, Kerry S Jones
Plasma 25-hydroxyvitamin D (25OHD) half-life (25OHDt 1/2) is a dynamic marker of vitamin D metabolism that can be used to assess vitamin D expenditure and help inform vitamin D requirements. Our group recently established an approach to determine the 25OHDt 1/2 as an alternative biomarker of 25OHD expenditure in humans. The approach uses a small oral dose of stable isotope labeled 25OHD3 [3-(2)H-25OHD(3) (6,19,19-d3)] (d3-25OHD3) (tracer), which is distinguishable from endogenous 25OHD by liquid chromatography tandem-mass spectrometry (LC-MS/MS)...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27884075/srm-based-measurements-of-proprotein-convertase-subtilisin-kexin-type-9-and-lipoprotein-a-kinetics-in-nonhuman-primate-serum
#14
Fang Xie, Maurice G Emery, John P Gibbs, Dan A Rock, Brooke M Rock
AIM: PCSK9 and Lp(a) have been identified as potential biomarkers for cardiovascular disease. The ability to measure protein turnover rates will provide insights into the dynamic properties of these proteins and lead to better understanding of their biological roles. We aimed to implement the stable isotope-labeled tracers ([(2)H3]-leucine) and develop a novel LC-selected reaction monitoring (SRM) mass spectrometry (MS) method to study the kinetics of PCSK9 and Lp(a). RESULTS: A sensitive method using immunoaffinity enrichment coupled with LC-SRM MS was developed to measure the production and degradation rates of PCSK9 and Lp(a) in naive nonhuman primate serum...
December 2016: Bioanalysis
https://www.readbyqxmd.com/read/27843065/measuring-radon-222-in-soil-gas-with-high-spatial-and-temporal-resolution
#15
Darren Huxtable, David Read, George Shaw
In order to exploit (222)Rn as a naturally-occurring tracer in soils we need to sample and measure radon isotopes in soil gas with high spatial and temporal resolution, without disturbing in situ activity concentrations and fluxes. Minimisation of sample volume is key to improving the resolution with which soil gas can be sampled; an analytical method is then needed which can measure radon with appropriate detection limits and precision for soil gas tracer studies. We have designed a soil gas probe with minimal internal dead volume to allow us to sample soil gas volumes of 45 cm(3)...
February 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27832302/rapid-ion-exchange-matrix-removal-for-a-decrease-of-detection-limits-in-the-analysis-of-salt-rich-reservoir-waters-for-fluorobenzoic-acids-by-liquid-chromatography-coupled-with-tandem-mass-spectrometry
#16
Paweł Kubica, Véronique Vacchina, Tomasz Wasilewski, Stéphanie Reynaud, Joanna Szpunar, Ryszard Lobinski
A matrix removal procedure with ion-exchange resin prior to analysis for 18 fluorinated benzoic acids (FBAs) tracers in saline (>25% salt) reservoir water was optimized. The elimination of >98% of salt and the simultaneous matrix sample cleanup allowed the direct analysis using the supernatant by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). This resulted in a gain in detection limits for most of the tracers in comparison with the reference method (direct analysis after minimum required dilution)...
February 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27766703/a-simple-and-reliable-anion-exchange-resin-method-for-sulfate-extraction-and-purification-suitable-for-multiple-o-and-s-isotope-measurements
#17
Erwann Le Gendre, Erwan Martin, Benoit Villemant, Pierre Cartigny, Nelly Assayag
RATIONALE: The O- and S-isotope compositions of sulfates can be used as key tracers of the fate and sink of sulfate in both terrestrial and extra-terrestrial environments. However, their application remains limited in those geological systems where sulfate occurs in low concentrations. Here we present a simple and reliable method to extract, purify and concentrate sulfate from natural samples. The method allows us to take into account the separation of nitrate, which is known to be an issue in O-isotope analysis...
January 15, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/27761615/a-strategy-for-simultaneous-determination-of-fatty-acid-composition-fatty-acid-position-and-position-specific-isotope-contents-in-triacylglycerol-matrices-by-13-c-nmr
#18
Noelle Merchak, Virginie Silvestre, Denis Loquet, Toufic Rizk, Serge Akoka, Joseph Bejjani
Triacylglycerols, which are quasi-universal components of food matrices, consist of complex mixtures of molecules. Their site-specific (13)C content, their fatty acid profile, and their position on the glycerol moiety may significantly vary with the geographical, botanical, or animal origin of the sample. Such variables are valuable tracers for food authentication issues. The main objective of this work was to develop a new method based on a rapid and precise (13)C-NMR spectroscopy (using a polarization transfer technique) coupled with multivariate linear regression analyses in order to quantify the whole set of individual fatty acids within triacylglycerols...
January 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27759065/effect-of-phytase-on-zinc-absorption-from-a-millet-based-porridge-fed-to-young-burkinabe-children
#19
M Brnić, R F Hurrell, L T Songré-Ouattara, B Diawara, A Kalmogho-Zan, C Tapsoba, C Zeder, R Wegmüller
BACKGROUND/OBJECTIVES: Fortifying cereal staples with zinc is a strategy for increasing zinc intake in young children in developing countries. However, phytic acid (PA) naturally present in cereals strongly decreases zinc absorption. A stable-isotope zinc absorption study was conducted in young children to investigate the ability of the PA-degrading enzyme phytase to improve zinc absorption, when added to a cereal porridge immediately before consumption. SUBJECTS/METHODS: Fractional absorption of zinc (FAZ) was estimated in 35 young healthy Burkinabe children using the double-isotopic tracer ratio method with (67)Zn as oral tracer and (70)Zn as intravenous tracer, in a crossover design...
January 2017: European Journal of Clinical Nutrition
https://www.readbyqxmd.com/read/27754354/analysis-of-mammalian-cell-proliferation-and-macromolecule-synthesis-using-deuterated-water-and-gas-chromatography-mass-spectrometry
#20
Victoria C Foletta, Michelle Palmieri, Joachim Kloehn, Shaun Mason, Stephen F Previs, Malcolm J McConville, Oliver M Sieber, Clinton R Bruce, Greg M Kowalski
Deuterated water (²H₂O), a stable isotopic tracer, provides a convenient and reliable way to label multiple cellular biomass components (macromolecules), thus permitting the calculation of their synthesis rates. Here, we have combined ²H₂O labelling, GC-MS analysis and a novel cell fractionation method to extract multiple biomass components (DNA, protein and lipids) from the one biological sample, thus permitting the simultaneous measurement of DNA (cell proliferation), protein and lipid synthesis rates...
October 13, 2016: Metabolites
keyword
keyword
39684
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"