MIE versus CIE: Comparative Analysis of Magnetic and Classical Isotope Effects

Бучаченко, А. Л.

doi:10.1021/cr00039a009

Cited by 112 publications

(67 citation statements)

References 28 publications

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“…It has also been established that 40% of brain hydrogen but only 10% of fatty acid hydrogen is derived from body water (for most tissues this figure is 20-30%). (51) In some reactions where radical or ion-radical intermediate state is involved, nuclear spin-selective processes (the magnetic IE (19) ) can play an important role; for example, phosphorylation reactions (52) can have 2.6-fold higher yields when nuclear spin-possessing 25 Mg 2þ ions are used instead of the spinless 24 Mg isotope. (53) Regrettably there are currently no data on isotope discrimination by living organisms based on this intriguing variety of the IE.…”

Section: Seamentioning

confidence: 99%

“…Equilibrium IEs arise when exchanges occur between molecules, such as an exchange between CO 2 in air and bicarbonate in the ocean: at equilibrium at 258C, the air will be depleted in 13 C relative to bicarbonate by up to 11%. (18) Magnetic IE depends on spin values (magnetic moments, I) of atomic nuclei (19) and plays a role in reactions that involve radicals. IE is also affected by pressure and temperature.…”

Section: Introductionmentioning

confidence: 99%

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Do “heavy” eaters live longer?

Shchepinov¹

2007

BioEssays

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A new hypothesis is put forward, linking cellular endurance with dietary consumption of stable heavy isotopes. Due to the isotope effect, biomolecules that incorporate heavier isotopes give rise to more stable molecular structures with increased resistance to damages associated with aging and age-related disease. The inclusion of heavy isotopes might be either active (selection for heavier isotopes) or passive (incorporation reflecting the existing abundance). The hypothesis links consumption of foods relatively rich in heavy isotopes (such as (13)C and D, derived from C4-plants), especially at the early stages of the organism's development, with enhanced longevity. Implications of diets and intestinal microflora are also discussed.

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Section: Seamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Do “heavy” eaters live longer?

Shchepinov¹

2007

BioEssays

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“…Being a phenomenon of fundamental importance, MIE offers a new tool for probing and testifying the reaction mechanisms, kinetics, and chemical physics of reactions. It can arise in spin-selective reactions of carbenes, triplet molecules, ions, and high-spin species, so that radical pair is not the only source of MIE [2].…”

Section: Magnetic Isotope Effectmentioning

confidence: 99%

Recent advances in spin chemistry

Бучаченко

2000

Pure and Applied Chemistry

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Abstract:The great success in controlling chemical reactivity by spin manipulation was achieved in the last decade, and many remarkable spin and magnetic phenomena have been discovered. Among those discoveries, the most chemically important highlights are magnetic isotope effect, spin catalysis, and single-spin tunneling spectroscopy. This paper summarizes recent advances in these new and hot areas of modern chemistry. GENERAL OUTLOOK OF SPIN CHEMISTRYSpin chemistry as a new land and hot area in modern chemistry is based on the universal and fundamental principle-all chemical reactions are spin selective. They allowed only for those spin states of products whose total electron spin is identical to that of reagents. The reactions are forbidden if they require a change of spin.Some typical examples of spin-selective reactions are given below. The recombination of radicals into the diamagnetic molecule is allowed from singlet state of the reaction precursor, radical pair:Triplet state is strictly forbidden for the reaction, so that triplet pair either dissociates to free radicals, or experiences spin conversion (shown by dashed arrow), which transforms nonreactive triplet state into the chemically reactive singlet state.Chemical addition of radical to triplet molecule (oxygen, for instance), as well as physical quenching of excited triplet molecule by radical, takes place only in doublet state:Quartet spin state is forbidden to react and quartet-doublet spin conversion is required to switch over the reaction channel. Again, spin selectivity is controlled by competition between the dissociation of the quartet pair on the starting reagents and spin transformation of the pair into the reactive doublet state.In the reaction of two triplets (recombination of carbenes, delayed fluorescence from the fusion of two excited triplet molecules, etc.) only one of the nine spin states is open to react: *Plenary lecture presented at the 15

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“…Moreover, mass independent isotopic fractionation has been observed [46][47][48][49]. In literature, possible causes of mass independent isotopic fractionation in MC ICP-MS were attributed to the nuclear field shift, the magnetic isotope effect, the oxide formation rate or high first ionization potentials [50].…”

Section: Measurement Related Factorsmentioning

confidence: 99%

Application of non-traditional stable isotopes in analytical ecogeochemistry assessed by MC ICP-MS - A critical review

Irrgeher

Prohaska

2015

Anal Bioanal Chem

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Analytical ecogeochemistry is an evolving scientific field dedicated to the development of analytical methods and tools and their application to ecological questions. Traditional stable isotopic systems have been widely explored and have undergone continuous development during the last century.The variations of the isotopic composition of light elements (H, O, N, C and S) have provided the foundation of stable isotope analysis followed by the analysis of traditional geochemical isotope tracers (e.g. Pb, Sr, Nd, Hf). Questions in a considerable diversity of scientific fields have been addressed, many of which can be assigned to the field of ecogeochemistry. Over the past fifteen years, other stable isotopes (e.g. Li, Zn, Cu, Cl) have emerged gradually as novel tools for the investigation of scientific topics that arise in ecosystem research and have enabled novel discoveries and explorations. These systems are often referred to as non-traditional isotopes.The small isotopic differences of interest that are increasingly being addressed for a growing number of isotopic systems represent a challenge to the analytical scientist and push the limits of today's instruments constantly. This underlines the importance of a metrologically sound concept of analytical protocols and procedures and a solid foundation of data processing strategies and uncertainty considerations before these small isotopic variations can be interpreted in the context of applied ecosystem research. This review focuses on the development of isotope research in ecogeochemistry, the requirements for successful detection of small isotopic shifts as well as highlights the most recent and innovative applications in the field. Keywordsanalytical ecogeochemistry, non-traditional stable isotopes, isotope tracers, MC ICP-MS, chemical metrology 2

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MIE versus CIE: Comparative Analysis of Magnetic and Classical Isotope Effects

Cited by 112 publications

References 28 publications

Do “heavy” eaters live longer?

Do “heavy” eaters live longer?

Recent advances in spin chemistry

Application of non-traditional stable isotopes in analytical ecogeochemistry assessed by MC ICP-MS - A critical review

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