Calcium isotopes in enamel of modern and Plio-Pleistocene East African mammals

Calcium isotope analyses show a depletion of heavy calcium isotopes in vertebrates, compared to food sources along each trophic step. Recent studies show considerable variability of the calcium isotopic composition of bone and teeth in modern mammals, leading to inconclusive interpretations regarding the utility of Ca isotopes for trophic inference in mammal-dominated terrestrial ecosystems. Here, we analyzed modern enamel samples from the Tsavo National Park (Kenya), and fossil enamel samples dated from ca. 4 Ma to 1.6 Ma from the Turkana Basin (Kenya). We found a constancy of taxa ordering between the modern and fossil datasets, suggesting that the diagenesis of calcium isotopes is minimal in fossils. In modern herbivore samples using similar digestive physiologies, browsers are enriched in Ca-44 compared to grazers. Both grazer and browser herbivore tooth enamel is enriched in Ca-44 relative to carnivores by about +0.30 parts per thousand. Used together, carbon and calcium isotope compositions may help refine the structure of the C-3 and C-4 trophic chains in the fossil record. Due to their high preservation potential, combining both carbon and calcium isotope systems represent a reliable approach to the reconstruction of the structure of past ecosystems. (C) 2018 Eisevier B.V. All rights reserved

Inferring odontocete life history traits in dentine using a multiproxy approach (δ15N, δ44/42Ca and trace elements)

Funding Information: The authors thank F. Demaret and W. Dabin (Observatoire Pelagis) for helping secure odontocete milk and tooth samples. This work was funded by the Conseil National de la Recherche Scientifique (CNRS) INSU INTERRVIE program (Early Whale Resource Use and Diet project) to J.E.M. The authors thank LGLTPE (UMR 5276) and ENS de Lyon for supporting the MC‐ICP mass spectrometry platform. Nitrogen isotope measurements were performed on the “Ecologie Isotopique” platform of LEHNA (UMR 5023). The authors thank F. Arnauld‐Godet and E. Albalat for technical support on the MC‐ICP platform of the LGLTPE. The authors thank the anonymous reviewers and the editor R. Bol for their constructive comments that helped improve the quality of this work. Funding Information: The authors thank F. Demaret and W. Dabin (Observatoire Pelagis) for helping secure odontocete milk and tooth samples. This work was funded by the Conseil National de la Recherche Scientifique (CNRS) INSU INTERRVIE program (Early Whale Resource Use and Diet project) to J.E.M. The authors thank LGLTPE (UMR 5276) and ENS de Lyon for supporting the MC-ICP mass spectrometry platform. Nitrogen isotope measurements were performed on the “Ecologie Isotopique” platform of LEHNA (UMR 5023). The authors thank F. Arnauld-Godet and E. Albalat for technical support on the MC-ICP platform of the LGLTPE. The authors thank the anonymous reviewers and the editor R. Bol for their constructive comments that helped improve the quality of this work. Publisher Copyright: © 2023 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.Peer reviewedPublisher PD

Calcium Isotopic Evidence for Vulnerable Marine Ecosystem Structure Prior to the K/Pg Extinction

International audienceThe collapse of marine ecosystems during the end-Cretaceous mass extinction involved the base of the food chain [1] up to ubiquitous vertebrate apex predators [2–5]. Large marine reptiles became suddenly extinct at the Cretaceous-Paleogene (K/Pg) boundary, whereas other contemporaneous groups such as bothremydid turtles or dyrosaurid crocodylomorphs, although affected at the familial, genus, or species level, survived into post-crisis environments of the Paleocene [5–9] and could have found refuge in freshwater habitats [10–12]. A recent hypothesis proposes that the extinction of plesiosaurians and mosasaurids could have been caused by an important drop in sea level [13]. Mosasaurids are unusually diverse and locally abundant in the Maastrichtian phosphatic deposits of Morocco, and with large sharks and one species of elasmosaurid plesiosaurian recognized so far, contribute to an overabundance of apex predators [3, 7, 14, 15]. For this reason, high local diversity of marine reptiles exhibiting different body masses and a wealth of tooth morphologies hints at complex trophic interactions within this latest Cretaceous marine ecosystem. Using calcium isotopes, we investigated the trophic structure of this extinct assemblage. Our results are consistent with a calcium isotope pattern observed in modern marine ecosystems and show that plesiosaurians and mosasaurids indiscriminately fall in the tertiary piscivore group. This suggests that marine reptile apex predators relied onto a single dietary calcium source, compatible with the vulnerable wasp-waist food webs of the modern world [16]. This inferred peculiar ecosystem structure may help explain plesiosaurian and mosasaurid extinction following the end-Cretaceous biological crisis

Geochemical identity of pre-Dogon and Dogon populations at Bandiagara (Mali, 11th–20th cent. AD)

Bone geochemistry of pre-Dogon (11th–16th cent. AD) and Dogon (17th–20th cent. AD) populations buried in two caves of the Bandiagara Cliff (Mali) was examined for the purpose of exploring their diet and mobility. While the Dogon were the subject of extensive ethnographic studies, the lifestyle of the pre-Dogon, so-called “Tellem” is not known. We therefore compared the geochemical composition of Dogon bones with the results obtained from modern dietary surveys in Mali, to establish the parameters of a dietary model that was further applied to the pre-Dogon in order to expand our knowledge concerning their way of life. The exceptional preservation of the bones of both populations was confirmed not only at the macroscopic scale, but also at the mineralogical, histological and geochemical levels, which resemble those of fresh bones, and therefore offered ideal conditions for testing this approach. 15The application of the Bayesian mixing model FRUITS, based on bone δ13C (apatite and collagen) and bone δ N values, suggested a dietary continuity through time, from the 11th century to today. Bone barium (Ba) content revealed very restricted mobility within the Cliff while bone δ18O values indicated that Pre-Dogon and Dogon most likely occupied the Bandiagara Plateau and the Cliff, respectively

Palaeoenvironmental reconstruction of the Sarmatian (Middle Miocene) Central Paratethys based on palaeontological and geochernical analyses of foraminifera, ostracods, gastropods and rodents

International audiencePaleoenvironmental changes in the upper Middle Miocene Central Parathetys were reconstructed by using qualitative and quantitative palaeontological analyses of foraminifera and ostracods, coupled with trace elemental (Mg/Ca) and stable isotope (delta(18)O and delta(13)C) analyses of their carbonate skeletons and of gastropod sheets. Mean annual air temperatures were estimated using the oxygen isotope composition of contemporaneous rodent teeth. The studied aquatic fossils come from two boreholes in the Zsambek basin (northern central Hungary), while the terrestrial ones are from localities in NE Hungary and E Romania. In the studied Sarmatian successions, three zones could be distinguished, based on palaeontological and geochemical results. At the Badenian/Sarmatian boundary, faunal diversity decreased markedly. In the lower zone a transgressive event culminated in a seawater incursion into the semi-open basin system of the Central Paratheys. Stable bottom-water temperature (similar to 15 degrees C) and variable salinites (20-22\%) are estimated for the Early Sarmatian Sea. The faunal changes (notably a strong reduction in biodiversity) occuring at the boundary between the lower and the middle zone can be explained by a sea-leval highstand with dysoxic conditions. A relative sea-level fall is documented at the end of this middle zone. After a short regressive event, a marine connection between the Paratethys and Mediterranean was established at the beginning of the upper zone. This is indicated by an increased microfaunal diversity and the re-appearance of marine Bademan ostracods and foraminifera, which are completely absent from the older Samatian series. During the upper zone, the temperatures and salmities are estimated to have fluctuated from 15 degrees C to 21 degrees C and from 15 parts per thousand to 43 parts per thousand, respectively

Breathing adapted radiotherapy: a 4D gating software for lung cancer

<p>Abstract</p> <p>Purpose</p> <p>Physiological respiratory motion of tumors growing in the lung can be corrected with respiratory gating when treated with radiotherapy (RT). The optimal respiratory phase for beam-on may be assessed with a respiratory phase optimizer (RPO), a 4D image processing software developed with this purpose.</p> <p>Methods and Materials</p> <p>Fourteen patients with lung cancer were included in the study. Every patient underwent a 4D-CT providing ten datasets of ten phases of the respiratory cycle (0-100% of the cycle). We defined two morphological parameters for comparison of 4D-CT images in different respiratory phases: tumor-volume to lung-volume ratio and tumor-to-spinal cord distance. The RPO automatized the calculations (200 per patient) of these parameters for each phase of the respiratory cycle allowing to determine the optimal interval for RT.</p> <p>Results</p> <p>Lower lobe lung tumors not attached to the diaphragm presented with the largest motion with breathing. Maximum inspiration was considered the optimal phase for treatment in 4 patients (28.6%). In 7 patients (50%), however, the RPO showed a most favorable volumetric and spatial configuration in phases other than maximum inspiration. In 2 cases (14.4%) the RPO showed no benefit from gating. This tool was not conclusive in only one case.</p> <p>Conclusions</p> <p>The RPO software presented in this study can help to determine the optimal respiratory phase for gated RT based on a few simple morphological parameters. Easy to apply in daily routine, it may be a useful tool for selecting patients who might benefit from breathing adapted RT.</p

Profiling of dynamics in protein–lipid–water systems: a time-resolved fluorescence study of a model membrane protein with the label BADAN at specific membrane depths

Profiles of lipid-water bilayer dynamics were determined from picosecond time-resolved fluorescence spectra of membrane-embedded BADAN-labeled M13 coat protein. For this purpose, the protein was labeled at seven key positions. This places the label at well-defined locations from the water phase to the center of the hydrophobic acyl chain region of a phospholipid model membrane, providing us with a nanoscale ruler to map membranes. Analysis of the time-resolved fluorescence spectroscopic data provides the characteristic time constant for the twisting motion of the BADAN label, which is sensitive to the local flexibility of the protein–lipid environment. In addition, we obtain information about the mobility of water molecules at the membrane–water interface. The results provide an unprecedented nanoscale profiling of the dynamics and distribution of water in membrane systems. This information gives clear evidence that the actual barrier of membranes for ions and aqueous solvents is located at the region of carbonyl groups of the acyl chains

High-resolution CT phenotypes in pulmonary sarcoidosis: a multinational Delphi consensus study

One view of sarcoidosis is that the term covers many different diseases. However, no classification framework exists for the future exploration of pathogenetic pathways, genetic or trigger predilections, patterns of lung function impairment, or treatment separations, or for the development of diagnostic algorithms or relevant outcome measures. We aimed to establish agreement on high-resolution CT (HRCT) phenotypic separations in sarcoidosis to anchor future CT research through a multinational two-round Delphi consensus process. Delphi participants included members of the Fleischner Society and the World Association of Sarcoidosis and other Granulomatous Disorders, as well as members' nominees. 146 individuals (98 chest physicians, 48 thoracic radiologists) from 28 countries took part, 144 of whom completed both Delphi rounds. After rating of 35 Delphi statements on a five-point Likert scale, consensus was achieved for 22 (63%) statements. There was 97% agreement on the existence of distinct HRCT phenotypes, with seven HRCT phenotypes that were categorised by participants as non-fibrotic or likely to be fibrotic. The international consensus reached in this Delphi exercise justifies the formulation of a CT classification as a basis for the possible definition of separate diseases. Further refinement of phenotypes with rapidly achievable CT studies is now needed to underpin the development of a formal classification of sarcoidosis