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Neil M. Johannsen and Rick L. Sharp

The purpose of this study was to investigate differences in substrate oxidation between dextrose (DEX) and unmodified (UAMS) and acid/alcohol-modified (MAMS) cornstarches. Seven endurance-trained men (VO2peak = 59.1 ± 5.4 mL·kg−1·min−1) participated in 2 h of exercise (66.4% ± 3.3% VO2peak) 30 min after ingesting 1 g/kg body weight of the experimental carbohydrate or placebo (PLA). Plasma glucose and insulin were elevated after DEX (P < 0.05) compared with UAMS, MAMS, and PLA. Although MAMS and DEX raised carbohydrate oxidation rate through 90 min of exercise, only MAMS persisted throughout 120 min (P < 0.05 compared with all trials). Exogenous-carbohydrate oxidation rate was higher in DEX than in MAMS and UAMS until 90 min of exercise. Acid/alcohol modification resulted in augmented carbohydrate oxidation with a small, sustained increase in exogenous-carbohydrate oxidation rate. MAMS appears to be metabolizable and available for oxidation during exercise.

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Alejandro M. Rosales, Nathan A. Keck, Tim C. Shriver, Dale A. Schoeller, and Brent C. Ruby

 filter to remove particulate and organic matter. Deuterium analysis was completed by reducing a 0.8 μl aliquot of cleaned urine samples over chromium at 850°C via Finnigan MAT H/Device. Resultant hydrogen was analyzed via a dual-inlet system on a Thermo Delta Plus isotope ratio mass spectrometer (San Jose

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Francesco Campa, Catarina N. Matias, Elisabetta Marini, Steven B. Heymsfield, Stefania Toselli, Luís B. Sardinha, and Analiza M. Silva

was given an oral dose of 0.1 g of 99.9%. H 2 O per kg of body weight (Sigma-Aldrich, St. Louis, MO) for the determination of TBW by deuterium dilution using a Hydra stable isotope ratio mass spectrometer (PDZ Europa; Europa Scientific, Cheshire, United Kingdom). Subjects were encouraged to void their

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Hiroyuki Sagayama, Makiko Toguchi, Jun Yasukata, Kazunari Yonaha, Yasuki Higaki, and Hiroaki Tanaka

, incorporating a special silicone gasket for the best possible seal, and were wrapped tightly with Parafilm M (Bemis Co., Inc., Oshkosh, WI). We analyzed the urine samples with isotope ratio mass spectrometry (Hydra 20-20 Stable Isotope Mass Spectrometer; SerCon Ltd., Crewe, United Kingdom). The 18 O and 2 H

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David R. Paul, Ryan McGrath, Chantal A. Vella, Matthew Kramer, David J. Baer, and Alanna J. Moshfegh

H 2 O per kilogram and 0.08 g of H 2 18 O per kilogram of body weight. 29 A 24-hour urine sample collected on the previous day was used to measure background isotope enrichments. Isotopic enrichment of urine samples was measured using continuous-flow isotope-ratio mass spectroscopy (Europa

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Rachel B. Parks, Hector F. Angus, Douglas S. King, and Rick L. Sharp

, it can be partially hydrolyzed with hydrochloric acid and alcohol, producing modified amylomaize-7, which is 92% digestible and readily soluble in water ( Zhou & Kaplan, 1997 ). Johannsen and Sharp ( 2007 ) used 13 C isotope-ratio analysis to demonstrate that modified amylomaize-7 starch is

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Megan Colletto and Nancy Rodriguez

isotope ratio mass spectroscopy (IRMS) by a commercial laboratory (Metabolic Solutions, Nashua NH) and corrected for background enrichment. Total urinary nitrogen was determined using the micro-Kjeldahl method (Tecator Kjeltec System, Hoganus, Sweden) for estimation of nitrogen excretion (NE). Nitrogen

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Ioanna Athanasiadou, Sven Christian Voss, Wesal El Saftawy, Hind Al-Jaber, Najib Dbes, Sameera Al-Yazedi, Waseem Samsam, Vidya Mohamed-Ali, Mohammed Alsayrafi, Georgia Valsami, and Costas Georgakopoulos

ratio of testosterone/epitestosterone, the biomarker that triggers gas chromatography–combustion–isotope ratio mass spectrometry (GC–C–IRMS) analysis for the detection of exogenous anabolic steroid abuse ( Goebel et al., 2009 ). Therefore, LH is included in the World Anti-Doping Agency (WADA) Prohibited

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Victoria C. Edwards, Stephen D. Myers, Sophie L. Wardle, Andrew G. Siddall, Steven D. Powell, Sarah Needham-Beck, Sarah S. Kefyalew, Priya A. Singh, Elise R. Orford, Michelle C. Venables, Sarah Jackson, Julie P. Greeves, and Sam D. Blacker

were frozen at −20°C until later analysis using isotope ratio mass spectrometry. The rate of CO 2 production was determined using the multipoint method of Schoeller et al. ( 1986 ) and converted to EE using the energy equivalent of CO 2 ( Elia & Livesey, 1988 ), assuming a respiratory quotient of 0