Stable heavy isotopes co‐exist with their lighter counterparts in all elements commonly found in biology. These heavy isotopes represent a low natural abundance in isotopic composition but impose great retardation effects in chemical reactions because of kinetic isotopic effects (KIEs). Previous isotope analyses have recorded pervasive enrichment or depletion of heavy isotopes in various organisms, strongly supporting the capability of biological systems to distinguish different isotopes. This capability has recently been found to lead to general decline of heavy isotopes (...) in metabolites during yeast aging. Conversely, supplementing heavy isotopes in growth medium promotes longevity. Whether this observation prevails in other organisms is not known, but it potentially bears promise in promoting human longevity. (shrink)

Mechanisms occurring at the atomic level are now known to drive processes essential for life, as revealed by quantum effects on biochemical reactions. Some macroscopic characteristics of organisms may thus show an atomic imprint, which may be transferred across organisms and affect their evolution. This possibility is considered here for the first time, with the aim of elucidating the appearance of an animal innovation with an unclear evolutionary origin: migratory behaviour. This trait may be mediated by a radical pair (RP) (...) mechanism in the retinal flavoprotein cryptochrome, providing essential magnetic orientation for migration. Isotopes may affect the performance of quantum processes through their nuclear spin. Here, we consider a simple model and then apply the standard open quantum system approach to the spin dynamics of cryptochrome RP. We changed the spin quantum number (I) and g‐factor of hydrogen and nitrogen isotopes to investigate their effect on RP's yield and magnetic sensitivity. Strong differences arose between isotopes with I = 1 and I = 1/2 in their contribution to cryptochrome magnetic sensitivity, particularly regarding Earth's magnetic field strengths (25–65 µT). In most cases, isotopic substitution improved RP's magnetic sensitivity. Migratory behaviour may thus have been favoured in animals with certain isotopic compositions of cryptochrome. (shrink)

A sample from the Ubatuba fragment collected in Brazil in 1957 was tested with the intent of examining the isotope ratios of its primary element, magnesium, and the trace elements strontium, barium, copper, and zinc. As background, the history of chemical testing of the Ubatuba fragments during the 1960s-1980s at multiple labs with varying capabilities is reviewed and then the remainder of the paper examines recent tests completed in 2017 and 2018 that for the first time used HR-ICPMS techniques (...) to look at the isotopic ratios of the minor constituents as well as the primary magnesium makeup of the sample. The magnesium isotope ratios were found to fall within terrestrial limits while the results on the isotope ratios of the trace elements was inconclusive. Recommendations are made for improving the process of examining the trace elements. Keywords: Ubatuba, isotope, magnesium, HR-ICPMS, UFO. (shrink)

The mechanistic significance of a kinetic isotope effect on a cytochrome P‐450catalyzed reaction depends, fundamentally, on the nature of the interaction of the substrate with the active site of the enzyme as well as on the nature of the chemistry of the reaction catalyzed. Consequently, kinetic isotope effects can be used to extract information on the topology of the enzyme and the mechanism of substrate oxidation. Kinetic isotope effect studies are sometimes accompanied by ‘metabolic switching’ or a (...) change in metabolic pathway, catalyzed either by the same enzyme or by a different enzyme. For the specific case where ‘metabolic switching’ gives rise to a change in regional specificity for the cytochrome P‐450 catalyzed metabolism of a compound, this change can be explained in terms of the topological constraints on substrate binding imposed by the active site of the enzyme. (shrink)

The precise position of a spectral line emitted by an atomic system depends on the mass of the atomic nucleus and is therefore different for isotopes belonging to the same element. The possible presence of an isotope effect followed from Bohr's atomic theory of 1913, but it took several years before it was confirmed experimentally. Its early history involves the childhood not only of the quantum atom, but also of the concept of isotopy. Bohr's prediction of the isotope (...) effect was apparently at odds with early attempts to distinguish between isotopes by means of their optical spectra. However, in 1920 the effect was discovered in HCl molecules, which gave rise to a fruitful development in molecular spectroscopy. The first detection of an atomic isotope effect was no less important, as it was by this means that the heavy hydrogen isotope deuterium was discovered in 1932. The early development of isotope spectroscopy led to successes as well as problems. At the end of the paper I briefly comment on the relationship between theory, experiment and prediction in this area of spectral physics. (shrink)

A model representing isotope separation during water evaporation in plants was constructed. The model accounts for substance diffusion, convective transfer and evaporation from the surface of the leaves. The dependence of the system’s separation and enrichment coefficients on various parameters was determined. A comparison was made between the enrichment coefficients calculated from experimental data from different plants and those based on the model. Qualitative agreement between the experimental and theoretical values was obtained for the case of $$\frac{uh}{D} {\gg} 1$$ (...) uh D ≫ 1, where u is the average velocity of water in the plant, h is the height of the plant, and D is the diffusion coefficient of the substance. (shrink)

This book describes the exciting discovery of every isotope observed on earth to date, which currently numbers some 3000. For each isotope a short essay highlights the authors of the first publication for the isotope, the laboratory and year where and when the isotope was discovered, as well as details about the production and detection methods used. In controversial cases previously claims are also discussed. At the end a comprehensive table lists all isotopes sorted by elements (...) and a complete list of references. Preliminary versions of these paragraphs have been published over the last few years as separate articles in the journal "Atomic Data and Nuclear Data Tables". The work re-evaluates all assignments judging them with a uniform set of criteria. In addition, the author includes over 100 new isotopes which have been discovered since the articles published. This book is a source of information for researchers as well as enthusiastic laymen alike. From the prepublication review: "The explanations focus on the essentials, which makes the various chapters pleasingly compact. The phrasing is well understandable also for non-experts. This makes the book easy to read, even thrilling. I have to confess that parts of the manuscript I was even reading as an evening lecture in the bed, so exciting was the history of isotope discoveries." Sigurd Hofmann, Helmholtz Professor at GSI Darmstadt, Germany, and a leading expert in superheavy nuclei. (shrink)

During the late 1940s and 1950s, radioisotopes became important resources for biological and medical research. This article explores the strategies used by French researchers to get access to this material, either from the local Atomic Energy Commission (CEA) or from suppliers in the United States or United Kingdom. It focuses on two aspects of this process: the transatlantic circulation of both isotopes and associated instrumentation; the regulation of use and access by the administrative bodies governing research in France. Analyzing the (...) investigations conducted within laboratories associated either with the atomic energy agency or with the local National Institute of Health (INH), the paper discusses the part played by the new tools in the postwar transformation of biomedical research. It contrasts the INH successful development of biological studies and metabolic tracing with the mixed results of CEA in advancing cancer radiotherapy, thus highlighting locally defined "normal paths" to radiobiology. (shrink)

I challenge Gareth Eaton’s recent claim that Theodore Richards should be counted among the discoverers of isotopes. In evaluating Eaton’s claim, I draw on two influential theories of scientific discovery, one developed by Thomas Kuhn, and one developed by Augustine Brannigan. I argue that though Richards’ experimental work contributed to the discovery, his work does not warrant attributing the discovery to him. Richards’ reluctance to acknowledge isotopes is well documented. Further, the fact that he made no claim to having made (...) the discovery also undermines Eaton’s argument. (shrink)

Recent studies suggest that a non‐isotopic in situ hybridisation (NISH) approach can be successfully employed to investigate the carrier status of female relatives in families of selected patients with Duchenne muscular dystrophy (DMD) or Hunter syndrome, whose diseases are due to a specific X chromosome deletion.Whilst the majority of metaphase spreads from normal females show specific hybridisation signals on both X chromosomes when tested with either dystrophin or Hunter gene‐derived probes, only one X chromosome in each metaphase spread will show (...) the relevant hybridisation complex in female carriers of deletions involving the dystrophin or Hunter gene.Thus, the NISH method can be a valuable diagnostic tool for the detection of the carrier status of female relatives of patients with X chromosome deletions. (shrink)

Whom should we credit for the discovery of isotopes? The first suggestion of an idea, the first experimental proof, or the development of a new method that clearly reveals the isotopes? Strömholm and Svedberg, Fajans and Soddy interpreted patterns of radioactive decay, which became confirmed theory on the solid basis of the very accurate atomic weight determinations by Richards and his coworkers. The mass spectrograph measurements by Aston provided major extension of the concept of isotopes to much of the rest (...) of the periodic table. Thus, Strömholm and Svedberg, Fajans and Soddy provided an idea, which Richards proved, and Aston made generally useful. Richards should be listed along with Fajans, Soddy, and Aston for fundamental contributions to establishing isotopes as part of the modern language of science. As much credit should be given to the experimental proof as to the suggestion or naming of the concept. (shrink)

Whom should we credit for the discovery of isotopes? The first suggestion of an idea, the first experimental proof, or the development of a new method that clearly reveals the isotopes? Strömholm and Svedberg, Fajans and Soddy interpreted patterns of radioactive decay, which became confirmed theory on the solid basis of the very accurate atomic weight determinations by Richards and his coworkers. The mass spectrograph measurements by Aston provided major extension of the concept of isotopes to much of the rest (...) of the periodic table. Thus, Strömholm and Svedberg, Fajans and Soddy provided an idea, which Richards proved, and Aston made generally useful. Richards should be listed along with Fajans, Soddy, and Aston for fundamental contributions to establishing isotopes as part of the modern language of science. As much credit should be given to the experimental proof as to the suggestion or naming of the concept. (shrink)

Whom should we credit for the discovery of isotopes? The first suggestion of an idea, the first experimental proof, or the development of a new method that clearly reveals the isotopes? Strömholm and Svedberg, Fajans and Soddy interpreted patterns of radioactive decay, which became confirmed theory on the solid basis of the very accurate atomic weight determinations by Richards and his coworkers. The mass spectrograph measurements by Aston provided major extension of the concept of isotopes to much of the rest (...) of the periodic table. Thus, Strömholm and Svedberg, Fajans and Soddy provided an idea, which Richards proved, and Aston made generally useful. Richards should be listed along with Fajans, Soddy, and Aston for fundamental contributions to establishing isotopes as part of the modern language of science. As much credit should be given to the experimental proof as to the suggestion or naming of the concept. (shrink)

This article presents the results of lead isotope analysis of ten Byzantine seals from the sigillographic collection of Robert Feind. The report is preceded by an overview of pre-existing studies on lead use in the Byzantine Empire and a presentation of the investigated seals datable to the Early Byzantine, Middle Byzantine and Late Byzantine period. Three seals are of imperial issue. The results of the analysis of lead are compared against the results of isotope analysis of other silver (...) and lead artefacts from Late Antiquity and the Late Byzantine period. The isotop analysis leads to the following conclusions: Many of the seals have isotope ratios consistent with Aegean-Bulgaria-Western Turkey sources; Reused lead was also employed in the manufacture of seals; There appear to be significant chronological and regional differences in the lead used for casting blanks in the eastern Mediterranean. The number of lead seals subjected here to analysis is admittedly too small for the results to be fully representative; still, they provide a starting point for more similar studies which will preferably include excavation finds with known and secure provenance. (shrink)

Cet article présente les résultats de l'analyse d'isotopes stables du carbone et de l'azote pratiquée sur des échantillons d'ossements humains issus des fouilles de l'habitat mésohelladique de l'Aspis. L'objectif de l'analyse est de reconstituer le régime alimentaire des habitants de l'Aspis et d'étudier les variations de régime entre des sous-groupes de population définis par des critères d'âge et de sexe et/ou de statut social. Sept échantillons ont été prélevés, dont quatre seulement ont fourni suffisamment de collagène pour être analysés. Les (...) données isotopiques indiquent que les habitants de l'Aspis avaient un régime alimentaire de type terrestre C3 relativement homogène ; toutefois, le seul individu de sexe masculin inhumé dans le cimetière semble avoir consommé plus de protéines animales (viande et/ou produits laitiers). Les ressources marines semblent avoir occupé une place négligeable dans l'alimentation des habitants de l'Aspis. D'une façon générale, le signal isotopique de leur régime alimentaire ne diffère pas fondamentalement de celui qui a été observé pour leurs contemporains de Lerne ou pour le groupe inhumé dans le Cercle Β de Mycènes. (shrink)

We investigate the Sp(2, R) model for light and heavy nuclei and compare it to recent applications of the Sp(6, R) model. The same Hamiltonian is used and the basis states will have good angular momentum. We not only confirm that the restricted space of the Sp(6, R) model gives the dominant contribution but also that there is no practical difference from the Sp(6, R) model calculations. The Sp(2, R) model is then applied to the chain of Ba-isotopes which show, (...) according to a recent application of the geometrical model, a dominant prolate behavior with an important γ-unstable component. They represent limiting cases where the Sp(2, R) model can be put to an extreme test. (shrink)