Joseph J. Bevitt

Polar wildfires and conifer serotiny during the Cretaceous global hothouse

Several highly effective fire-adaptive traits first evolved among modern plants duringthe mid-Cretaceous, in response to the widespread wildfires promoted by anomalously highatmospheric oxygen (O2) ...

Neutron tomography of Austrosequoia novae-zeelandiae comb. nov. (Late Cretaceous, Chatham Islands, New Zealand): implications for Sequoioideae phylogeny and biogeography

The Tupuangi Flora of the Chatham Islands, New Zealand, reveals a south polar forest ecosystem, and important biogeographical links between eastern and western Gondwana. We employed neutron tomography (NT) to image fossil Cupressaceae seed cones from the Upper Cretaceous (Cenomanian) strata of the Tupuangi Formation. This technique facilitated the non-destructive ‘virtual extraction’ of three-dimensional, coalified specimens, whilst they were still embedded within a large volume of supporting silicate sedimentary rock. This study is the first reported application of NT in palaeobotanical taxonomy, and the combination of virtual and manual extraction techniques enabled a more complete treatment than would otherwise be possible if taxonomic data were limited to only one of these approaches. The seed cones were identified as Austrosequoia novae-zeelandiae (Ettingshausen) Mays & Cantrill comb. nov. In this case, NT data supplemented the compression fossil data by providing details such as the three-dimensional measurements of the gross morphology, and accurate estimations of bract-scale complex number. Furthermore, this technique appears to show promise in differentiating between organic compounds within an individual specimen. However, anatomical details and fine-scale morphology were indiscernible due to present limitations in spatial resolution. Austrosequoia novae-zeelandiae is interpreted as a stem group of Sequoioideae; it shares synapomorphic seed cone characters with extant sequoioids (e.g. Sequoia and Sequoiadendron), and plesiomorphic stomatal structures and leaf morphology. Abundant epiphyllous fungi (Plochmopeltinites sp.; Microthyriaceae) were also identified on the leaf cuticles of A. novae-zeelandiae. The high abundance of Austrosequoia in the Tupuangi Flora supports a cupressaceous floral province at south polar latitudes during the early Late Cretaceous. Furthermore, this stem group of Sequoioideae in eastern Gondwana during the early Late Cretaceous suggests an alternative, south-to-north dispersal route of sequoioids before the final continental separation of eastern and western Gondwana.

Pushing the limits of neutron tomography in palaeontology: three-dimensional modelling of in situ resin within fossil plants

Computed tomography is an increasingly popular technique for the non-destructivestudy of fossils. Whilst the science of X-ray computed tomography (CT) has greatlymatured since its first fossil appl ...

Cyclic-RGDyC functionalized liposomes for dual-targeting of tumor vasculature and cancer cells in glioblastoma: An in vitro boron neutron capture therapy study

The efficacy of boron neutron capture therapy depends on the selective delivery of 10B to the target. Integrins αvβ3 are transmembrane receptors over-expressed in both glioblastoma cells and its neovasculature. In this study, a novel approach to dual-target glioblastoma vasculature and tumor cells was investigated. Liposomes (124 nm) were conjugated with a αvβ3 ligand, cyclic arginine-glycine-aspartic acid-tyrosine-cysteine peptide (c(RGDyC)-LP) (1% molar ratio) through thiol-maleimide coupling. Expression of αvβ3 in glioblastoma cells (U87) and human umbilical vein endothelial cells (HUVEC), representing tumor angiogenesis, was determined using Western Blotting with other cells as references. The results showed that both U87 and HUVEC had stronger expression of αvβ3 than other cell types, and the degree of cellular uptake of c(RGDyC)-LP correlated with the αvβ3-expression levels of the cells. In contrast, control liposomes without c(RGDyC) showed little cellular uptake, regardless of cell type. In an in vitro boron neutron capture therapy study, the c(RGDyC)-LP containing sodium borocaptate generated more rapid and significant lethal effects to both U87 and HUVEC than the control liposomes and drug solution. Interestingly, neutron irradiated U87 and HUVEC showed different types of subsequent cell death. In conclusion, this study has demonstrated the potential of a new dual-targeting strategy using c(RGDyC)-LP to improve boron neutron capture therapy for glioblastoma.

Differential preservation of vertebrates in Southeast Asian caves

Caves have been an important source of vertebrate fossils for much of Southeast Asia, particularly for the Quaternary. Despite this importance, the mechanisms by which vertebrate remains accumulate and preserve in Southeast Asian caves has never been systematically reviewed or examined. Here, we present the results of three years of cave surveys in Indonesia and Timor-Leste, describing cave systems and their attendant vertebrate accumulations in diverse geological, biogeographical, and environmental settings. While each cave system is unique, we find that the accumulation and preservation of vertebrate remains are highly dependent on local geology and environment. These factors notwithstanding, we find the dominant factor responsible for faunal deposition is the presence or absence of biological accumulating agents, a factor directly dictated by biogeographical history. In small, isolated, volcanic islands, the only significant accumulation occurs in archaeological settings, thereby limiting our understanding of the palaeontology of those islands prior to human arrival. In karstic landscapes on both oceanic and continental islands, our understanding of the long-term preservation of vertebrates is still in its infancy. The formation processes of vertebrate bearing breccias, their taphonomic histories, and the criteria used to determine whether these represent syngenetic or multiple deposits remain critically understudied. The latter in particular has important implications for arguments on how breccia deposits from the region should be analysed and interpreted when reconstructing palaeoenvironments.

DINGO – the neutron imaging station at ANSTO: embracing material science, palaeontology, and cultural heritage

Volume 27 • Number 2 • 2016 Neutron News 14 Introduction After one year of hot commissioning, Australia jumped to the forefront of neutron imaging with the startup of the instrument DINGO on the OPAL reactor at ANSTO in early 2014. With barely a dozen neutron imaging stations world-wide, this brought the much-needed capability of state-of-the-art neutron radiography and neutron tomography setups [1, 2] to the Asia-Oceania region. Acquisition speed and spatial resolution can be tuned by choosing amongst different sets of apertures, scintillation screens, and detector systems to meet the needs of the broad user community. Researchers, curators, and industrial clients now have access to one of the highest-intensity neutron-imaging instruments in the world, able to obtain detailed radiographs of scientifi c objects, museum artefacts, and engineering pieces in seconds to minutes, three-dimensional tomographs in several hours, and movies of processes such as running engines or motors, and the fl ow of fl uids in fuel cells, all non-destructively.

Neutron scanning reveals unexpected complexity in the enamel thickness of an herbivorous Jurassic reptile

Eilenodontines are one of the oldest radiation of herbivorous lepidosaurs (snakes, lizards and tuatara) characterized by batteries of wide teeth with thick enamel that bear mammal-like wear facets. Unlike most reptiles, eilenodontines have limited tooth replacement, making dental longevity particularly important to them. We use both X-ray and neutron computed tomography to examine a fossil tooth from the eilenodontine Eilenodon (Late Jurassic, USA). Of the two approaches, neutron tomography was more successful and facilitated measurements of enamel thickness and distribution. We find the enamel thickness to be regionally variable, thin near the cusp tip (0.10 mm) but thicker around the base (0.15–0.30 mm) and notably greater than that of other rhynchocephalians such as the extant Sphenodon (0.08–0.14 mm). The thick enamel in Eilenodon would permit greater loading, extend tooth lifespan and facilitate the establishment of wear facets that have sharp edges for orally processing plant material such as horsetails (Equisetum). The shape of the enamel dentine junction indicates that tooth development in Eilenodon and Sphenodon involved similar folding of the epithelium but different ameloblast activity.

Discovering dinosaurs with neutrons

Combining data from neutron and X-ray techniques can reveal previously unseen details within fossilized remains. Interpretation of vast amounts of data by students speeds up the gathering of information and engages young scientists in the discovery process.

A Non-Destructive Investigation of two Cypriot Bronze Age Knife Blades using Neutron Diffraction Residual Stress Analysis

This paper presents the results of a residual stress analysis that is part of a wider study of Cypriot Bronze Age knife and other weapon blades from a corpus of artefacts held by a number of institutions in Australia. The current focus is on knives from Early/Middle Bronze Age burial sites at Bellapais Vounous, Cyprus; a significant number of the blades were found on excavation to be bent. The aim of the study was to provide, by means of non-destructive neutron residual stress analysis, likely insights into fabrication methodologies of the knives and determine the stage in the life of each knife blade at which bending occurred. Two Vounous knives from the Australian Institute of Archaeology collection, one measurably bent and the other severely bent and broken, were studied using neutron diffractometer KOWARI to establish the residual stress profiles through the thickness of the knives at several locations. Since the knives were 1 2 mm thick at their thinnest sections, a very high through-thickness spatial resolution of 0.1 mm was used to resolve the residual stress profiles. The experimental data from the knives suggested forging/hammering as a possible method of fabrication of functional (hard edge) knife blade. Most significantly, however, the post fabrication bending of both knives at ambient temperature was established. The residual stress data for the two knives were considered in the context of reported metallurgical studies and the archaeological information from Cypriot Bronze Age sites. Introduction The work reported in this paper brings together some aspects of the physical metallurgy of a specific corpus of artefacts from the well-documented burial site Bellapais Vounous, Fig. 1, an Early/Middle Bronze Age site in Cyprus (c 2450-1700 BCE). The site is a cemetery of over 160 tombs that were excavated by a number of archaeologists; notably Dikaios [3] and Stewart and Stewart [4]. Post excavation, the metallic artefacts, (including spearhead, knives and razors) and others of pottery were distributed to a small number of museums in England and Australia. Many of the Vounous artefacts available for study in Australia are provenanced to specific tombs at the site; and thus can be used to Fig. 1. Map of Cyprus showing the location of Bellapais Vounous and other Early/Middle Bronze Age sites (after [1, 2]). Residual Stresses 2016: ICRS-10 Materials Research Forum LLC Materials Research Proceedings 2 (2016) 515-520 doi: http://dx.doi.org/10.21741/9781945291173-87 516 provide insights into origins of raw material, use of the material, fabrication methods and treatment of the artefacts when used as burial items. These objects belong to early phase metallurgy in Cyprus and therefore offer insight into the nature and origins of its ancient copper industry. One particular feature of the Early/Middle Cypriot Bronze Age burials is that a significant number of knife and spear blades from this, and other, Bronze Age sites were found, on excavation, to be bent. Many scholars have noted the deliberate destruction or disabling of metal weapons in burial contexts (e.g. [2, 5-7]). Often referred to as ‘ritual killing’, the act of disabling is believed to have taken place at the burial site and assumed to have been intended to enable the weapons to accompany the dead and perhaps ensure that they could not be used as weapons after burial. Any insights into the fabrication route of the knives and determining the stage in the life of each knife blade at which bending occurred are highly desirable. There have been limited metallurgical studies of Vounous metallic artefacts and much of the work to date has provided elemental analyses [1, 8], Pb isotope analysis [1] and metallography [9]. Through the metallographic analysis [9], there is a notion that the blades/weapons had been cold worked from original states, most likely cast blanks, annealed and then additionally cold worked to their final form. Since residual stresses are intrinsically linked to each these processes, there is a potential to provide new and corroborating information about the fabrication and treatment or handling of the Early/Middle Bonze Age bronze artefacts from fabrication and post-fabrication perspectives and possibly to support the view of ritual bending practices at some ancient Cypriot burials. Although application of neutron diffraction to study ancient bronzes has been reported [10], there are currently limited data and, to the authors’ knowledge, no studies of residual stresses or textures within the corpus of Vounous artefacts. The current paper reports the results of the application of non-destructive neutron diffraction methods to two Bronze Age knife blades from Vounous. Samples Two knives from the Australian Institute of Archaeology, AIA, Vounous artefacts IA 2.525 and 2.268 (Fig. 2), were submitted for neutron diffraction residual stress study and chemical analysis at the Australian Nuclear Science and Technology Organisation, ANSTO. Both knives were found bent in situ. Artefact IA 2.525 was bent through 180° and was found fractured. Artefact IA 2.268, was bent to approximately 40° at the mid-section of the blade. Fig. 2. Two knife blades, IA 2.525 (left) and IA 2.268 (right), from the Stewart excavations at Bellapais Vounous [4]. For IA 2.525, only the section illustrated within the red boundary was available for study while the severely bent section of the blade was lost some time after photographic recording for reference 4. Residual Stresses 2016: ICRS-10 Materials Research Forum LLC Materials Research Proceedings 2 (2016) 515-520 doi: http://dx.doi.org/10.21741/9781945291173-87 517 Elemental characterization of IA 2.525 and IA 2.268 The chemical compositions of the two Vounous knives were determined by combined Proton Induced X-Ray Emission spectroscopy (PIXE) and Proton Induced Gamma-ray Spectroscopy (PIGE) using 2.5 MeV proton beam at the ANSTO Centre for Accelerator Science. The chemical analyses of other Vounous artefacts studied in work of Webb et al. [1] and Craddock [8] demonstrated that the majority of blades analyzed were essentially Cu-As alloys with, usually, 2.5-5 wt.% As. The two Vounous blades studied in this work were significantly different alloys, with As < 0.5 wt%.; IA 2.525 contained 1.30 wt% Zn and only a trace of Sn and IA 2.268 contained 0.56 wt % Zn and 0.66 wt% Sn. The absence As suggests that the knifes were struck from a low As indigenous copper ore. With the arsenic content of IA 2.525 and IA 2.268 at < 0.5 wt%, much lower than threshold of 2.0 wt%, which some archaeologists believe is an indicator of deliberate alloying with this element, the ability to develop a hardened cutting edge would have been limited. As modern chemical analyses have shown, for copper blades from Cypriot Early/Middle Bronze Age sites, including Vounous, As was most likely added as an ore in the smelting process the result of which aided casting and increased propensity for work hardening [11]. The presence of Zn in IA 2.525 confirms an earlier analysis reported in Stewart and Stewart [4]. Balthazar [9] and other researchers have noted the presence of Zn in some Early/Middle Bronze Age artefacts but no conclusions about its presence have been drawn, other than questioning some earlier analytical methods. Further chemical analyses of Cypriot artefacts in Australian institutions are proposed and these may provide additional insights regarding Zn and other elements as alloying elements. Neutron residual stress measurements The residual stresses within the two Vounous knives were determined using the ANSTO KOWARI neutron stress diffractometer. [12]. Neutron diffraction stress measurements were undertaken at three gauge locations (L1, L2 and L3) on IA 2.268 (Fig. 3) and at one location (L1) on IA 2.525 (Fig. 4), to determine the stress profiles through each of the blades. With thickness of the blades varying from 1 to 2 mm, through-thickness stresses were measured with a relatively high spatial resolution of 0.1 mm in through-thickness dimension. The strongest Cu(311) reflection was used for the residual stress measurements at wavelength of 1.55 Å. A gauge volume of 0.1×0.1×10 mm was used for the measurements in the three principal directions (longitudinal, normal and transverse) at the central line of the blades, at L1 and L2, however for measurements in the thinnest section of IA 2.268 the gauge volume, at L3, was reduced to 0.1×0.1×7 mm. To fully resolve the stress state, a zero normal stress condition was used to calculate stresses with high accuracy at the same time making possible non-destructive determination of each lattice parameter d0 of the alloy. A large number of measurement points through thickness, 9-13, with 0.1 mm steps, was considered necessary to determine several possible contributions to the total residual profile (hot forging, cold hammering, bending, etc.) which were resolved and separated. With measurement time of only 10-20 minutes per through-thickness position, a strain accuracy of 50 μstrains was routinely achieved. Fig. 3. Approximate locations of the three positions used for residual stress measurements of IA 2.268. Fig. 4. Approximate locations of the position used for residual stress measurements of IA 2.525 Residual Stresses 2016: ICRS-10 Materials Research Forum LLC Materials Research Proceedings 2 (2016) 515-520 doi: http://dx.doi.org/10.21741/9781945291173-87 518 Results and discussion The results of the residual stress measurements at the gauge locations L1, L2 and L3 for IA 2.268 are shown in Fig. 5 a,b,c and for gauge location L1 for IA 2.525 in Fig. 6. The through-thickness residual stress profiles of the transverse direction are similar for both blades and all locations. However, the transverse component of the thicker knife IA 2.525 at position L1 seems to incorporate also a bending stress component (slope) that is superimposed by the surrounding parts of the blade other than the location of measur