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Littérature scientifique sur le sujet « Isotopomer molecules »

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Articles de revues sur le sujet "Isotopomer molecules"

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Hellerstein, M. K., C. Kletke, S. Kaempfer, K. Wu et C. H. Shackleton. « Use of mass isotopomer distributions in secreted lipids to sample lipogenic acetyl-CoA pool in vivo in humans ». American Journal of Physiology-Endocrinology and Metabolism 261, no 4 (1 octobre 1991) : E479—E486. http://dx.doi.org/10.1152/ajpendo.1991.261.4.e479.

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Measurement of hepatic fatty acid (FA) and cholesterol synthesis has been limited by lack of access to the precursor pool, cytosolic acetyl-CoA. We present a method for inferring the enrichment of the true hepatic lipogenic precursor pool in humans using the frequency distribution of mass isotopomers within enriched circulating polymers of acetyl-CoA [very low-density lipoprotein (VLDL)-palmitate, VLDL-stearate]. Human subjects were infused intravenously (n = 16) with [1-13C]- or [2-13C]acetate. Oral sulfamethoxazole (SMX) was administered concurrently, and the acetylated conjugate (SMX acetate) was used to estimate independently the hepatic cytosolic acetyl-CoA enrichment. Isotopomer frequencies in VLDL-FA were determined by gas chromatography-mass spectrometry, whereas high-performance liquid chromatography-mass spectrometry was used to measure enrichments in SMX acetate. Based on the excess M2/excess M1 ratio in VLDL-FA, calculated acetyl-CoA enrichments were 5.59 +/- 0.33 molar percent excess (MPE), whereas SMX acetate enrichments were 5.38 +/- 0.31 MPE (the 2 methods were not significantly different). Mass isotopomer-calculated and SMX acetate-measured estimates of acetyl-CoA enrichments correlated very closely in individual subjects (r2 = 0.93; P less than 0.0001). De novo hepatic lipogenesis can be measured using isotopomer-calculated precursor enrichments compared with measured incorporation in specific isotopomers of VLDL-FA. In summary, excess isotopomer frequencies in secreted lipids provide a non-invasive technique for estimating hepatic cytosolic acetyl-CoA enrichments in humans in vivo and correlate closely with enrichments observed using the xenobiotic probe technique. Isotopomeric distributions represent a new strategy for accurate measurement of macromolecule synthesis that may be applicable to other classes of molecules besides lipids.
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Rousu, Juho, Ari Rantanen, Raimo A. Ketola et Juha T. Kokkonen. « Isotopomer distribution computation from tandem mass spectrometric data with overlapping fragment spectra ». Spectroscopy 19, no 1 (2005) : 53–67. http://dx.doi.org/10.1155/2005/575686.

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We present a method for determination of the isotopomer distributions of metabolites from the data generated by a tandem mass spectrometer. The method is an improvement over existing method as it is able to deal with overlapping fragments in the spectra. Our experiments indicate that the new method surpasses its predecessors in separating isotopomers from each other. When using the daughter ion scanning (collision induced dissociation) mode, the method was shown to be able to constrain the isotopomer distribution of different amino acids better than two existing methods. In particular, the isotopomer distributions of three amino acids, glycine, alanine and serine, can be fully uncovered with the method. However, due to the imperfect fragmentation of molecules in the tandem mass spectrometer, isotopomer distributions of larger amino acids still cannot be fully uncovered. In tests with isotope-labelled alanine, most accurate results were obtained using multiple reaction monitoring and 15 eV collision energy. The meausured isotopomer frequecies were in the range 99?106% of the theoretical value and the deviation between repetitions was in the range 1?10%.
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Hellerstein, M. K., et R. A. Neese. « Mass isotopomer distribution analysis : a technique for measuring biosynthesis and turnover of polymers ». American Journal of Physiology-Endocrinology and Metabolism 263, no 5 (1 novembre 1992) : E988–1001. http://dx.doi.org/10.1152/ajpendo.1992.263.5.e988.

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Mass isotopomer distribution analysis (MIDA) is a technique for measuring biosynthesis and turnover of polymers in vivo. A stable isotopically enriched precursor is administered, and the relative abundances of different mass isotopomers in the polymer of interest are measured by mass spectrometry (MS). By comparison of statistical distributions predicted from the binomial or multinomial expansion to the pattern of excess isotopomer frequencies observed in the polymer, the enrichment of the biosynthetic precursor subunits (p) for newly synthesized polymers is calculated. MIDA thereby provides a solution to the problem of determining the isotope content in the actual precursor molecules that entered a particular polymeric product (the “true” precursor). The fraction of polymer molecules in a mixture that were newly synthesized during an isotopic experiment (fractional synthesis) can then be calculated. We describe some mathematical characteristics of MIDA and point out certain advantageous features. For example, mathematical estimates of p remain valid even if there does not exist a single anatomic or functional precursor pool. The interpretation of decay curves of endogenously labeled polymers may be improved by the use of higher mass isotopomers, which better fulfill the assumption of flash labeling. By combining fractional synthesis values with rate constants of decay, absolute endogenous synthesis rates can be calculated. Thus, by using probability logic combined with MS analysis, MIDA allows dynamic measurements to be made through analyses on a polymer alone during both isotopic incorporation and decay phases. The method has been applied to fatty acids, cholesterol, and glucose and is potentially applicable to nucleic acids, porphyrins, perhaps proteins, and many other classes of polymers.
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Lee, Wai-Nang Paul, Laszlo G. Boros, Joaquim Puigjaner, Sara Bassilian, Shu Lim et Marta Cascante. « Mass isotopomer study of the nonoxidative pathways of the pentose cycle with [1,2-13C2]glucose ». American Journal of Physiology-Endocrinology and Metabolism 274, no 5 (1 mai 1998) : E843—E851. http://dx.doi.org/10.1152/ajpendo.1998.274.5.e843.

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We present a single-tracer method for the study of the pentose phosphate pathway (PPP) using [1,2-13C2]glucose and mass isotopomer analysis. The metabolism of [1,2-13C2]glucose by the glucose-6-phosphate dehydrogenase, transketolase (TK), and transaldolase (TA) reactions results in unique pentose and lactate isotopomers with either one or two13C substitutions. The distribution of these isotopomers was used to estimate parameters of the PPP using the model of Katz and Rognstad (J. Katz and R. Rognstad. Biochemistry 6: 2227–2247, 1967). Mass and position isotopomers of ribose, and lactate and palmitate (products from triose phosphate) from human hepatoma cells (Hep G2) incubated with 30% enriched [1,2-13C2]glucose were determined using gas chromatography-mass spectrometry. After 24–72 h incubation, 1.9% of lactate molecules in the medium contained one 13C substitution ( m 1) and 10% contained two 13C substitutions ( m 2). A similar m 1-to- m 2ratio was found in palmitate as expected. Pentose cycle (PC) activity determined from incubation with [1,2-13C2]glucose was 5.73 ± 0.52% of the glucose flux, which was identical to the value of PC (5.55 ± 0.73%) determined by separate incubations with [1-13C] and [6-13C]glucose.13C was found to be distributed in four ribose isotopomers ([1-13C]-, [5-13C]-, [1,2-13C2]-, and [4,5-13C2]ribose). The observed ribose isotopomer distribution was best matched with that provided from simulation by substituting 0.032 for TK and 0.85 for TA activity relative to glucose uptake into the model of Katz and Rognstad. The use of [1,2-13C2]glucose not only permits the determination of PC but also allows estimation of relative rates through the TK and TA reactions.
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Kelleher, J. K., et T. M. Masterson. « Model equations for condensation biosynthesis using stable isotopes and radioisotopes ». American Journal of Physiology-Endocrinology and Metabolism 262, no 1 (1 janvier 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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Des Rosiers, C., B. R. Landau et H. Brunengraber. « Interpretation of isotopomer patterns in tracing glycogen synthesis and glucose recycling using [13C6]glucose ». American Journal of Physiology-Endocrinology and Metabolism 259, no 5 (1 novembre 1990) : E757—E762. http://dx.doi.org/10.1152/ajpendo.1990.259.5.e757.

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Tracing glycogen synthesis with [U-13C]glucose involves determination of isotopomer patterns in precursors and products. The contribution of the direct pathway to glycogen synthesis has been estimated from the ratio (R) of the number of glycogen glucose molecules having six 13C atoms to the total number of glucose molecules having one to six 13C atoms. Using theoretical examples, we show that the equation to calculate R underestimates the contribution of the direct pathway. We derive a correct stoichiometric expression for R. Also, we show how to correct these estimates for 1) recondensation of two M+3 three-carbon intermediates into M+6 glucose 6-phosphate, and 2) the increasing enrichment of arterial glucose in various isotopomers arising from the indirect pathway. Finally, using the developed formulas we recalculate data from the literature. Similar considerations apply to investigations of glucose recycling using [U-13C6]glucose.
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Kelleher, Joanne K. « Estimating gluconeogenesis with [U-13C]glucose : molecular condensation requires a molecular approach ». American Journal of Physiology-Endocrinology and Metabolism 277, no 3 (1 septembre 1999) : E395—E400. http://dx.doi.org/10.1152/ajpendo.1999.277.3.e395.

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Recently three equations for estimating gluconeogenesis in vivo have been proposed, two by J. A. Tayek and J. Katz [ Am. J. Physiol. 270 ( Endocrinol. Metab. 33): E709–E717, 1996, and Am. J. Physiol. 272 ( Endocrinol. Metab. 35): E476–E484, 1997] and one by B. R. Landau, J. Wahren, K. Ekberg, S. F. Previs, D. Yang, and H. Brunengraber [ Am. J. Physiol.274 ( Endocrinol. Metab. 37): E954–E961, 1998]. Both groups estimate gluconeogenesis from cycling of [U-13C]glucose to lactate and back to glucose, detected by mass spectrometry. Landau’s approach is based on analysis of labeled molecules, whereas Tayek and Katz’s is based on labeling of carbon atoms by use of the concept of “molar enrichment,” which weights each mass isotopomer by the number of labeled carbons. We derived an equation very similar to Landau’s using binomial probability. Our analysis demonstrates that the molecular-based approach is correct. Additionally, equations appropriate for 14C studies are not appropriate for 13C studies, because the method used to detect14C, decay of atoms, differs from13C mass isotopomers detected as labeled molecules. We conclude that the molar enrichment carbon-based approach is not useful in the derivation of equations for the polymerization of molecules detected by mass spectrometry of molecules, and we confirm the findings of Landau et al.
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Ajie, H. O., M. J. Connor, W. N. Lee, S. Bassilian, E. A. Bergner et L. O. Byerley. « In vivo study of the biosynthesis of long-chain fatty acids using deuterated water ». American Journal of Physiology-Endocrinology and Metabolism 269, no 2 (1 août 1995) : E247—E252. http://dx.doi.org/10.1152/ajpendo.1995.269.2.e247.

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To determine the contributions of preexisting fatty acid, de novo synthesis, and chain elongation in long-chain fatty acid (LCFA) synthesis, the synthesis of LCFAs, palmitate (16:0), stearate (18:0), arachidate (20:0), behenate (22:0), and lignocerate (24:0), in the epidermis, liver, and spinal cord was determined using deuterated water and mass isotopomer distribution analysis in hairless mice and Sprague-Dawley rats. Animals were given 4% deuterated water for 5 days or 8 wk in their drinking water. Blood was withdrawn at the end of these times for the determination of deuterium enrichment, and the animals were killed to isolate the various tissues for lipid extraction for the determination of the mass isotopomer distributions. The mass isotopomer distributions in LCFA were incompatible with synthesis from a single pool of primer. The synthesis of palmitate, stearate, arachidate, behenate, and lignocerate followed the expected biochemical pathways for the synthesis of LCFAs. On average, three deuterium atoms were incorporated for every addition of an acetyl unit. The isotopomer distribution resulting from chain elongation and de novo synthesis can be described by the linear combination of two binomial distributions. The proportions of preexisting, chain elongation, and de novo-synthesized fatty acids as a percentage of the total fatty acids were determined using multiple linear regression analysis. Fractional synthesis was found to vary, depending on the tissue type and the fatty acid, from 47 to 87%. A substantial fraction (24-40%) of the newly synthesized molecules was derived from chain elongation of unlabeled (recycled) palmitate.
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Lee, W. N., S. Bassilian, Z. Guo, D. Schoeller, J. Edmond, E. A. Bergner et L. O. Byerley. « Measurement of fractional lipid synthesis using deuterated water (2H2O) and mass isotopomer analysis ». American Journal of Physiology-Endocrinology and Metabolism 266, no 3 (1 mars 1994) : E372—E383. http://dx.doi.org/10.1152/ajpendo.1994.266.3.e372.

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Fractional biosynthesis of palmitate, stearate, and cholesterol was determined with deuterated water (2H2O) using mass isotopomer analysis in Hep G2 and MCA sarcoma cells in culture. The method employed differs from previous ones in that the number of deuterium atoms from 2H2O incorporated into newly synthesized molecules was determined and not assumed. After correction for background natural abundances, the isotopomer distribution due to deuterium incorporation in fatty acids and cholesterol was shown to follow a simple binomial distribution depending on the deuterium enrichment in water (p) and the maximum number of deuterium atoms incorporated per molecule (N). Under a wide range of 2H2O enrichments, N could be determined to be 17 for palmitate, 20 for stearate, and 20 for cholesterol by regression analysis or from a series of consecutive mass isotopomer ratios. The fraction derived from de novo synthesis was given by the ratio of the observed to the theoretical deuterium enrichment, which is the product (N x p). The new synthesized fraction of palmitate and stearate by Hep G2 cells for the length of the experiment was found to be 77 and 65%, respectively. These values were confirmed by experiments with [U-13C]glucose as the precursor. In MCA sarcoma cells grown in lipid-poor medium, the average values for fractional synthesis of palmitate, stearate, and cholesterol were 70, 35, and 70%, respectively. This approach should be generally applicable to the simultaneous determined of fractional synthesis of a number of compounds with either deuterium or 13C tracers. Its application is only limited by the accuracy of mass spectrometric analysis.
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Rosenblatt, J., D. Chinkes, M. Wolfe et R. R. Wolfe. « Stable isotope tracer analysis by GC-MS, including quantification of isotopomer effects ». American Journal of Physiology-Endocrinology and Metabolism 263, no 3 (1 septembre 1992) : E584—E596. http://dx.doi.org/10.1152/ajpendo.1992.263.3.e584.

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In metabolic tracer studies it is frequently useful to infuse tracers that are differently labeled variants of the same molecule. These tracers are known as isotopomers. Analysis of the enrichment of each isotopic analogue can be accomplished by gas chromatography-mass spectrometry (GC-MS). However, the raw GC-MS data must be corrected to give the information required. This paper addresses how to transform the raw GC-MS data, consisting of relative abundance ratios at specific ion masses, into relative molar ratios of tracer and tracee molecules. Several correction factors are necessary. First, the background must be measured and corrected for, since it is always present in the sample. Second, the abundances in the spectrum of the labeled molecule are different from those in the unlabeled molecule, and this proportionality "skew" is corrected. A third correction factor accounts for the overlapping spectra of two or more isotopomers that cannot be measured independently. The final correction removes the "double vision" effect that may appear in some spectra due to the presence of (M - H)+ species.
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Thèses sur le sujet "Isotopomer molecules"

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Sit, Swapan Kumar. « High frequency absorptions, double relaxation times, dipole moments and molecular structures of some nonspherical polar and isotopomer molecules ». Thesis, University of North Bengal, 1997. http://hdl.handle.net/123456789/668.

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Murphy, Brian Timothy. « Isotopomeric carbon compounds in star formation regions ». Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270812.

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Valenanzo, Loredana. « Calculation of fully non-adiabatic properties of the hydrogen molecular cation and its isotopomers ». Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274534.

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Sutikdja, Lilian W. [Verfasser]. « Studies of esters and their isotopomers using the molecular beam fourier transform microwave (MB-FTMW) spectroscopy / Lilian W. Sutikdja ». Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1059563940/34.

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Boopalachandran, Praveenkumar. « Spectroscopic Studies of Pyridine and its Isotopomer, 2-Fluoro- and 3-Fluoropyridine, 1,3-Butadiene and Its Isotopomers ». Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10243.

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The infrared, Raman and ultraviolet spectra of pyridine-d0 and pyridine-d5 were recorded and assigned with a focus on the low-frequency vibrational modes in the S1(n,pi*) electronic excited state. An energy map for the low-frequency modes was constructed and the data for the v18 mode allowed a highly anharmonic one-dimensional potential energy function to be determined for the S1 excited state. In this S1(n,pi*) state, pyridine is quasi-planar and very floppy with a barrier to planarity of 3 cm^-1. The infrared, Raman and ultraviolet spectra of 2-fluoropyridine (2FPy) and 3-fluoropyridine (3FPy) have been collected and assigned. For 2FPy about 150 bands were observed for the transitions to the vibronic levels of the S(pi, pi*) state at 38,030.4 cm^-1. For 3FPy more than a hundred absorption bands associated with the S(n,pi*) state at 35,051.7 cm^-1 and about forty broad bands associated with the S(pi, pi*) state at 37,339 cm^-1 were observed. The experimental work was complemented by ab initio calculations and these also provided calculated structures for 2FPy, 3FPy, and pyridine. They showed that the fluorine atom on the ring participates in the pi bonding. The gas-phase Raman spectra of 1,3-butadiene and its 2,3-d2, 1,1,4,4-d4, and d6 isotopomers have been recorded with high sensitivity in the region below 350 cm-1, in order to investigate the internal rotation (torsional) vibration. The data for all the isotopomers were then fit using a one-dimensional potential energy function of the form V = (1/2)Sigma(Vn(1-cos (phi))). The energy difference between trans and gauche forms was determined to be about 1030 cm^-1 (2.94 kcal/mol), and the barrier between the two equivalent gauche forms to be about 180 cm^-1 (0.51 kcal/mol), which agrees well with high-level ab initio calculations. The results from an alternative set of assignments also fits the data quite well are also presented. Combination and hot band series involving the v13 torsional vibration of the trans rotamer were observed for each of the butadiene isotopomers. In addition, the high signal to noise of the Raman spectra made it possible to detect several dozen bands of the gauche rotor which makes up only about 2% of the molecules at ambient temperature.
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Livres sur le sujet "Isotopomer molecules"

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Webster, Frank J. O. Calculated reactivity of H+H2 and its isotopomers. Chicago, USA : Chicago U.P., 1988.

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Calculated reactivity of H+H2 and its isotopomers . dissertation, 1988.

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webster, frank J. O. Calculated reactivity of H+H2 and its isotopomers. dissertation and university of chicago, 1987.

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Calculated reactivity of H+H2 and its isotopomers. University of Chicago, 1987.

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Calculated reactivity of H+H2 and its isotopomers. University of Chicago, 1988.

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Webster, Frank J. O. Calculated reactivity of H+H2 and its isotopomers. 1988.

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Chapitres de livres sur le sujet "Isotopomer molecules"

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Carvalho, Francisco X., Bárbara Guerra-Carvalho, Ivana Jarak et Rui A. Carvalho. « Mitochondrial Regulation Assessment by 13C-NMR Isotopomer Analysis ». Dans Methods in Molecular Biology, 259–70. New York, NY : Springer US, 2021. http://dx.doi.org/10.1007/978-1-0716-1433-4_14.

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Young, Jamey D., Douglas K. Allen et John A. Morgan. « Isotopomer Measurement Techniques in Metabolic Flux Analysis II : Mass Spectrometry ». Dans Methods in Molecular Biology, 85–108. Totowa, NJ : Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-661-0_7.

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Truong, Quyen X., Jong Moon Yoon et Jacqueline V. Shanks. « Isotopomer Measurement Techniques in Metabolic Flux Analysis I : Nuclear Magnetic Resonance ». Dans Methods in Molecular Biology, 65–83. Totowa, NJ : Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-661-0_6.

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Kramer, Zeb C., et Rex T. Skodje. « A semiclassical adiabatic calculation of state densities for molecules exhibiting torsion : application to hydrogen peroxide and its isotopomers ». Dans Gregory S. Ezra, 53–65. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-47377-1_6.

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Cotrufo, M. Francesca, et Yamina Pressler. « Stable Isotopes, Notations, and Standards ». Dans A Primer on Stable Isotopes in Ecology, 7–24. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198854494.003.0002.

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Abstract “Stable Isotopes, Notations, and Standards” reviews the foundational concepts necessary for understanding and reporting stable isotopes data using appropriate notation and reference standards. The chapter defines stable isotopes and describes the isotopic composition of carbon, nitrogen, oxygen, hydrogen, and sulfur. Isotopocules are described as molecules differing in their isotopic composition, known as isotopologues, or for having different isotopic substitution, known as isotopomers. Isotones and isobars are also defined. Stable isotope data are examined using delta, fractional, and atom percent notations. Formulae to convert isotope data across notations are described. The chapter examines the history and use of international reference standards for isotopic analysis.
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Quack, M., et M. A. Suhm. « Potential energy surfaces, quasiadiabatic channels, rovibrational spectra, and intramolecular dynamics of (HFh and its isotopomers from quantum Monte Carlo calculations ». Dans Quantum Monte Carlo, 72. Oxford University PressNew York, NY, 2007. http://dx.doi.org/10.1093/oso/9780195310108.003.0075.

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Abstract The hydrogen fluoride dimer (HF)2 is the simplest molecule exhibiting the phenomenon of a hydrogen bond. In this case, the hydrogen fluoride molecules are loosely held together by the relatively weak hydrogen bond to produce a floppy molecule with anharmonic vibrations not easily characterized, but producing an interesting and complex spectroscopy. In this paper, Quack and Suhm report the use of the diffusion QMC method in analyzing the behavior of the dimer and its isotopomers, and the successful prediction and assignment of spectral bands observed in their earlier experiments.a The DQMC calculations were carried out for nuclear motion on two different six-dimensional potential energy surfaces adjusted to reproduce experimentally measured spectra including anharmonic interactions between all vibrational modes. Two new QMC methods for calculating excited rotational and vibrational states were introduced: a clamped-coordinate quasiadiabatic channel and a centrifugal-energy approximation scheme. In general, quantitative agreement with experimental observations was obtained, and the success of DQMC methods in the prediction and analysis of the spectra of hydrogen-bonded systems was clearly demonstrated. The large differences in electron and proton masses led to extensive computation requirements due to the slow equilibration and serial correlation induced by the heavier protons. The calculations were executed on one of the first massively parallel computers, a Thinking Machines CM-2 with 65,536 processors. Frequent communication among the processors was required to balance the number of walkers treated in each.
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Actes de conférences sur le sujet "Isotopomer molecules"

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Pate, Brooks, et Martin Holdren. « A SYNTHETIC METHODOLOGY TO PRODUCE TAILORED DEUTERATION PATTERNS IN BUILDING BLOCK MOLECULES WITH HIGH ISOTOPOMER SPECIFICITY VERIFIED BY MOLECULAR ROTATIONAL SPECTROSCOPY ». Dans 2023 International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2023. http://dx.doi.org/10.15278/isms.2023.7223.

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Dagdigian, Paul J., et Jing Chen. « Spectroscopy and excited state dynamics of the HNF (DNF) molecule ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.tul7.

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Laser fluorescence excitation of the HNF molecule, and its isotopomer DNF, have been detected in the A ˜ 2 A ′ − χ ˜ 2 A ″ band system for the F + HN3 (DN3) reaction. This observation indicates this reaction forms HNF + N2, in addition to the well known HF + N3 products. To our knowledge this is the first report of laser fluorescence detection of this molecule, for which the ground and excited electronic states form a Renner–Teller pair with bent equilibrium internuclear geometries. The K structure of the bands is observed to become simpler with increasing bending excitation, reflecting the reduction in the highest observable K′ levels. Decay lifetimes were measured for a variety of excited levels. The decay rate was observed to increase abruptly at an energy 23,800 ± 500 cm−1 above the HNF ( χ ˜ ) zero-point level. This threshold is tentatively assigned to the onset of a predissociation channel. The excited state dynamics of HNF (DNF) will be compared with the dynamics of the well-studied Renner–Teller molecules HCO and HNO.
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Johnson, Mark, et Conrad Wolke. « ISOLATING SITE-SPECIFIC SPECTRAL SIGNATURES OF INDIVIDUAL WATER MOLECULES IN H-BONDED NETWORKS WITH ISOTOPOMER-SELECTIVE, IR-IR DOUBLE RESONANCE VIBRATIONAL PREDISSOCIATION SPECTROSCOPY ». Dans 71st International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2016. http://dx.doi.org/10.15278/isms.2016.wi01.

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Xu, Li-Hong, et R. M. Lees. « FTIR Spectra and Torsion-Vibration Coupling in 13CD3OH ». Dans High Resolution Spectroscopy. Washington, D.C. : Optica Publishing Group, 1993. http://dx.doi.org/10.1364/hrs.1993.pd5.

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Methanol is one of the simplest molecule capable of large amplitude torsional motion. This couples with the vibrational motions and has significant effects on the infrared spectrum, illustrated at low resolution in Fig. 1 for the 13CD3OH isotopomer in the 950-1450 cm-1 region. The complex torsion-vibration energy structure of 13CD3OH is shown in Fig. 2. Level crossings occur among a variety of states giving numerous Fermi and Coriolis interactions. Thus, methanol offers a good test platform for the study of intramolecular vibrational relaxation (IVR) with torsional effects. Furthermore, the ready availability of different isotopomers allows us to seek insight into individual torsion-vibration interaction mechanisms through the substantial changes in symmetry coordinate mixing and vibrational interaction which occur upon isotopic substitution. So far, different bands of 13CH3OH, CH318OH, CD3OH and 13CD3OH as well as the normal 12CH316OH species have all been studied by several groups around the world.1-7
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Nataraj, Akshay, Michele Gianella, Béla Tuzson, Gang Li, Volker Ebert, Jérôme Faist et Lukas Emmenegger. « Cool mid-IR Absorption Spectroscopy of cold Molecules ». Dans Optics and Photonics for Sensing the Environment. Washington, D.C. : Optica Publishing Group, 2022. http://dx.doi.org/10.1364/es.2022.etu4h.7.

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We present a QCL based absorption spectroscopy setup with a Stirling cooled circular multipass absorption cell at 150 K. We report the first high-precision measurements of clumped 12C18O2 and 12C17O18O, and of site-specific propane isotopomers.
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Sonstrom, Reilly, Brooks Pate, W. Harman, Jacob Smith et Patrick Kelleher. « ISOTOPOLOGUE AND ISOTOPOMER ANALYSIS OF DEUTERATED CYCLOHEXENE USING MOLECULAR ROTATIONAL RESONANCE SPECTROSCOPY ». Dans 2020 International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2020. http://dx.doi.org/10.15278/isms.2020.fc04.

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West, Channing, Justin Neill, Leo Joyce, Haifeng Yang, Brooks Pate et Patrick Kelleher. « ISOTOPOMER DISTRIBUTION IN DEUTERATED ACTIVE PHARMACEUTICAL INGREDIENTS MEASURED BY MOLECULAR ROTATIONAL RESONANCE SPECTROSCOPY ». Dans 2020 International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2020. http://dx.doi.org/10.15278/isms.2020.ri09.

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Margulès, L., Emmanuel Caux, Charlotte Vastel, J. C. Guillemin et R. Motiyenko. « MILLIMETERWAVE SPECTRO OF HYDROXYACETONITRILE (HOCH2CN) ISOTOPOMERS AND THEIR SEARCH IN ISM ». Dans 2020 International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2020. http://dx.doi.org/10.15278/isms.2020.tc01.

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Warin, S., J. J. Vwnayoun et Y. P. Viala. « Photodissociation and rotational excitation of CO and its isotopomers in interstellar clouds ». Dans The 50th international meeting of physical chemistry : Molecules and grains in space. AIP, 1994. http://dx.doi.org/10.1063/1.46627.

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Frum, C. I., R. Engleman et P. F. Bernath. « Fourier-transform emission spectroscopy ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.thi6.

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The vibration-rotation spectrum of silicon monosulfide, an important astrophysical molecule, has been observed in emission between 640 and 800 cm–1 using the Fourier-transform spectrometer associated with the McMath Solar Telescope at Kitt Peak. Gas-phase SiS was produced by the reaction of solid silicon with silicon disulfide, SiS2, in an alumina heat pipe oven. More than 2400 lines were assigned to four isotopomers (28Si32S, 28Si34S, 29Si32S and 30Si32S). The data for all the isotopomers series were fitted together using the mass-reduced Dunham expression including Watson's Born-Oppenheimer breakdown coefficients. The infrared spectrum of the antisymmetric stretching mode, v3, of BeF2 has been observed in emission near 1530 cm-1. Gas-phase BeF2 was produced by heating solid beryllium difluoride to about 800°C in a heat pipe oven. The spectra were recorded at a resolution of 0.005 cm–1 using a KC1 beam splitter and Si:As detectors.
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