I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[4940]
Open Access
Abstract: In order to provide important details concerning the adsorption reactions of Sr, batch reactions and a set of both ex situ and in situ Grazing Incidence X-ray Absorption Fine Structure (GIXAFS) adsorption experiments were completed on powdered TiO2 and on rutile(110), both reacted with either SrCl2 or SrCO3 solutions. TiO2 sorption capacity for strontium (Sr) ranges from 550 ppm (SrCl2 solutions, second order kinetics) to 1400 ppm (SrCO3 solutions, first order kinetics), respectively, and is rapid. Sr adsorption decreased as a function of chloride concentration but significantly increased as carbonate concentrations increased. In the presence of carbonate, the ability of TiO2 to remove Sr from the solution increases by a factor of ~4 due to rapid epitaxial surface precipitation of an SrCO3 thin film, which registers itself on the rutile(110) surface as a strontianite-like phase (d-spacing 2.8 Å). Extended X-ray Absorption Fine Structure (EXAFS) results suggest the initial attachment is via tetradental inner-sphere Sr adsorption. Moreover, adsorbates from concentrated SrCl2 solutions contain carbonate and hydroxyl species, which results in both inner- and outer-sphere adsorbates and explains the reduced Sr adsorption in these systems. These results not only provide new insights into Sr kinetics and adsorption on TiO2 but also provide valuable information concerning potential improvements in effluent water treatment models and are pertinent in developing treatment methods for rutile-coated structural materials within nuclear power plants.
|
Dec 2021
|
|
I18-Microfocus Spectroscopy
|
Phillip L.
Manning
,
Nicholas P.
Edwards
,
Uwe
Bergmann
,
Jennifer
Anne
,
William
Sellers
,
Arjen
Van Veelen
,
Dimosthenis
Sokaras
,
Victoria M.
Egerton
,
Roberto
Alonso-Mori
,
Konstantin
Ignatyev
,
Bart E.
Van Dongen
,
Kazumasa
Wakamatsu
,
Shosuke
Ito
,
Fabien
Knoll
,
Roy A.
Wogelius
Diamond Proposal Number(s):
[12948, 11865, 9488, 8597, 7749]
Open Access
Abstract: Recent progress has been made in paleontology with respect to resolving pigmentation in fossil material. Morphological identification of fossilized melanosomes has been one approach, while a second methodology using chemical imaging and spectroscopy has also provided critical information particularly concerning eumelanin (black pigment) residue. In this work we develop the chemical imaging methodology to show that organosulfur-Zn complexes are indicators of pheomelanin (red pigment) in extant and fossil soft tissue and that the mapping of these residual biochemical compounds can be used to restore melanin pigment distribution in a 3 million year old extinct mammal species (Apodemus atavus). Synchotron Rapid Scanning X-ray Fluorescence imaging showed that the distributions of Zn and organic S are correlated within this fossil fur just as in pheomelanin-rich modern integument. Furthermore, Zn coordination chemistry within this fossil fur is closely comparable to that determined from pheomelanin-rich fur and hair standards. The non-destructive methods presented here provide a protocol for detecting residual pheomelanin in precious specimens.
|
May 2019
|
|
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[15129, 19516]
Abstract: The complexity and heterogeneity of bone chemistry makes it difficult to discern information on physiological and taphonomic processes stored within the bone matrix. Analysis of archaeological and palaeontological bone becomes more difficult because in many cases the most pivotal specimens are too scientifically valuable for destructive analysis. This problem is further escalated by the fact that the heterogeneity of the bone may cause small “pockets” of preservation that can be missed during sampling. Therefore, a non-destructive technique that can spatially resolve such heterogeneity within the bone is needed. Here we use microfocus, non-destructive synchrotron-based X-Ray Fluorescence (XRF) imaging and X-ray Absorption Spectroscopy (XAS) to map the organic constituents within extant and fossil bovid bones. XAS analysis of sulfur allowed organic sulfur (within collagen as methionine) to be distinguished from inorganic sulfate (within bone apatite). Mapping and quantification of organic sulfur within the samples were made by setting the beam to the methionine resonance, allowing for the detection, distribution and quantification of collagen present by using organic sulfur as an internal marker. Results show organic sulfur to be distributed in small “pockets” throughout the bone matrix in both extant and fossil specimens. Significant loss of collagen (organic sulfur) was seen in specimens between 100 ka and 650 ka with little organic sulfur preservation persisting after this date. Comparison of residual organic sulfur concentrations as a function of sample age revealed a second order rate law for organic sulfur oxidation (k ≈ 1 × 10−5 y−1) within bone. These results show that non-destructive, synchrotron-based XRF mapping of organic sulfur is a useful tool for not only calculating rates of collagen degradation through time, but also identifying areas of potential collagen preservation for other paleobiological applications such as proteomics and stable isotope analyses.
|
Jan 2019
|
|
I18-Microfocus Spectroscopy
|
Jennifer
Anne
,
Roya A.
Wogelius
,
Nicholas P.
Edwards
,
Arjen
Van Veelen
,
Michael
Buckley
,
William
Sellers
,
Uwe
Bergmann
,
Dimosthenis
Sokaras
,
Roberto
Alonso-Mori
,
Virginia L.
Harvey
,
Victoria M.
Egerton
,
Phillip L.
Manning
Diamond Proposal Number(s):
[9488]
Abstract: Trace element inventories are known to correlate with specific histological structures in bone, reflecting organismal physiology and life histories. By studying trace elements in fossilised bone, particularly in individuals with cyclic bone growth (alternating fast/slow bone deposition), we can improve our understanding of the physiology of extinct organisms. In this study we present the first direct comparison between optical histology (bone tissue identification) and synchrotron-based chemical mapping, quantification, and characterisation of trace elements (biochemistry) within cyclic growth tissues, in this case within bones of a cave hyaena (Crocuta crocuta spelaea). Results show distributions of zinc, an element strongly associated with active ossification and bone growth, correlating with (1) fast-growing tissue of zonal bone (cyclic growth) in an extinct hyaena and (2) secondary osteons (remodelling) in both extant and extinct hyaena. Concentrations and coordination chemistry of zinc within the fossil sample are comparable to those seen in extant bone suggesting that zinc is endogenous to the sample and that the chemistry of bone growth has been preserved for 40 ka. These results demonstrate that the study of trace elements as part of the histochemistry has wide utility for reconstructing growth, diet and other lifestyle factors in archaeological and fossil bone.
|
Oct 2018
|
|
I18-Microfocus Spectroscopy
|
Fabien
Knoll
,
Luis M.
Chiappe
,
Sophie
Sanchez
,
Russell J.
Garwood
,
Nicholas P.
Edwards
,
Roy A.
Wogelius
,
William I.
Sellers
,
Phillip L.
Manning
,
Francisco
Ortega
,
Francisco J.
Serrano
,
Jesús
Marugán-Lobón
,
Elena
Cuesta
,
Fernando
Escaso
,
Jose Luis
Sanz
Diamond Proposal Number(s):
[11865]
Open Access
Abstract: Fossils of juvenile Mesozoic birds provide insight into the early evolution of avian development, however such fossils are rare. The analysis of the ossification sequence in these early-branching birds has the potential to address important questions about their comparative developmental biology and to help understand their morphological evolution and ecological differentiation. Here we report on an early juvenile enantiornithine specimen from the Early Cretaceous of Europe, which sheds new light on the osteogenesis in this most species-rich clade of Mesozoic birds. Consisting of a nearly complete skeleton, it is amongst the smallest known Mesozoic avian fossils representing post-hatching stages of development. Comparisons between this new specimen and other known early juvenile enantiornithines support a clade-wide asynchronous pattern of osteogenesis in the sternum and the vertebral column, and strongly indicate that the hatchlings of these phylogenetically basal birds varied greatly in size and tempo of skeletal maturation.
|
Mar 2018
|
|
B18-Core EXAFS
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[11865]
Abstract: Endochondral ossification is the process by which bone is deposited during development, growth and repair of the skeleton. The regulation of endochondral ossification is extremely important as developmental flaws can result in severe skeletal abnormalities. However, until recently the limitations of available methodologies have restricted our understanding of this fundamental physiological process. The analysis of chemical elements that are intimately associated with discrete biochemical stages of ossification within bone could provide new insight to such processes at the atomic level. In this study we present detailed characterisation of the elemental inventory within actively ossifying bone during development in mice using synchrotron microfocus X-ray techniques. X-ray fluorescence imaging showed differential distributions of Zn, Sr and Ca, which may be correlated with the processes of cartilage replacement (Zn), active ossification (Sr) and fully ossified tissues (Ca). Quantification of these trace elements confirmed their relative distributions. These results represent the first detailed visualisation of local endochondral ossification processes using trace elemental mapping. Such studies have far reaching applications not only in the medical field, but to our understanding of the evolution of the bony skeleton given that trace element inventories have been shown to be preserved through deep time (millions of years).
|
Mar 2017
|
|
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[9488]
Open Access
Abstract: The hindlimb of theropod dinosaurs changed appreciably in the lineage leading to extant birds, becoming more ‘crouched’ in association with changes to body shape and gait dynamics. This postural evolution included anatomical changes of the foot and ankle, altering the moment arms and control of the muscles that manipulated the tarsometatarsus and digits, but the timing of these changes is unknown. Here, we report cellular-level preservation of tendon- and cartilage-like tissues from the lower hindlimb of Early Cretaceous Confuciusornis. The digital flexor tendons passed through cartilages, cartilaginous cristae and ridges on the plantar side of the distal tibiotarsus and proximal tarsometatarsus, as in extant birds. In particular, fibrocartilaginous and cartilaginous structures on the plantar surface of the ankle joint of Confuciusornis may indicate a more crouched hindlimb posture. Recognition of these specialized soft tissues in Confuciusornis is enabled by our combination of imaging and chemical analyses applied to an exceptionally preserved fossil.
|
Mar 2017
|
|
I18-Microfocus Spectroscopy
|
Nicholas
Edwards
,
Arjen
Van Veelen
,
Jennifer
Anné
,
Phillip
Manning
,
Uwe
Bergmann
,
William
Sellers
,
Victoria
Egerton
,
Dimosthenis
Sokaras
,
Roberto
Alonso-Mori
,
Kazumasa
Wakamatsu
,
Shosuke
Ito
,
Roy A.
Wogelius
Diamond Proposal Number(s):
[11865, 12948]
Open Access
Abstract: Melanin is a critical component of biological systems, but the exact chemistry of melanin is still imprecisely known. This is partly due to melanin’s complex heterogeneous nature and partly because many studies use synthetic analogues and/or pigments extracted from their natural biological setting, which may display important differences from endogenous pigments. Here we demonstrate how synchrotron X-ray analyses can non-destructively characterise the elements associated with melanin pigment in situ within extant feathers. Elemental imaging shows that the distributions of Ca, Cu and Zn are almost exclusively controlled by melanin pigment distribution. X-ray absorption spectroscopy demonstrates that the atomic coordination of zinc and sulfur is different within eumelanised regions compared to pheomelanised regions. This not only impacts our fundamental understanding of pigmentation in extant organisms but also provides a significant contribution to the evidence-based colour palette available for reconstructing the appearance of fossil organisms.
|
Sep 2016
|
|
I18-Microfocus Spectroscopy
|
S. T.
Williams
,
S.
Ito
,
K.
Wakamatsu
,
T.
Goral
,
Nicholas
Edwards
,
R A
Wogelius
,
T.
Henkel
,
L. F. C.
De Oliveira
,
L. F.
Maia
,
S.
Strekopytov
,
T.
Jeffries
,
D. I.
Speiser
,
J. T.
Marsden
Diamond Proposal Number(s):
[9488]
Open Access
Abstract: Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this study shows that homology of visible colour cannot be assumed without identification of pigments.
|
Jul 2016
|
|
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[9488, 8597]
Open Access
Abstract: Bone remodelling is a crucial biological process needed to maintain elemental homeostasis. It is important to understand the trace elemental inventories that govern these processes as malfunctions in bone remodelling can have devastating effects on an organism. In this study, we use a combination of X-ray techniques to map, quantify, and characterise the coordination chemistry of trace elements within the highly remodelled bone tissues of extant and extinct Sirenia (manatees and dugongs). The dense bone structure and unique body chemistry of sirenians represent ideal tissues for studying both high remodelling rates as well as unique fossilisation pathways. Here, elemental maps revealed uncorrelated patterning of Ca and Zn within secondary osteons in both extant and fossil sirenians, as well as elevated Sr within the connecting canals of fossil sirenians. Concentrations of these elements are comparable between extant and fossil material indicating geochemical processing of the fossil bone has been minimal. Zn was found to be bound in the same coordination within the apatite structure in both extant and fossil bone. Accurate quantification of trace elements in extant material was only possible when the organic constituents of the bone were included. The comparable distributions, concentrations, and chemical coordination of these physiologically important trace elements indicate the chemistry of bone remodelling has been preserved for 19 million years. This study signifies the powerful potential of merging histological and chemical techniques in the understanding of physiological processes in both extant and extinct vertebrates.
|
Mar 2016
|
|
