Scanning Synchrotron Research Articles

Te vacancy-driven superconductivity in orthorhombic molybdenum ditelluride

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have received great attentions because of diverse quantum electronic states such as topological insulating (TI), Weyl semimetallic (WSM) and superconducting states. Recently, the superconducting states emerged in pressurized semimetallic TMDs such as MoTe2 and WTe2 have become one of the central issues due to their predicted WSM states. However, the difficulty in synthetic control of chalcogen vacancies and the ambiguous magneto transport properties have hindered the rigorous study on superconducting and WSM states. Here, we report the emergence of superconductivity at 2.1 K in Te-deficient orthorhombic Td-MoTe2−x with an intrinsic electron-doping, while stoichiometric monoclinic 1T′-MoTe2 shows no superconducting state down to 10 mK, but exhibits a large magnetoresistance of 32 000% at 2 K in a magnetic field of 14 T originating from nearly perfect compensation of electron and hole carriers. Scanning tunnelling spectroscopy and synchrotron x-ray diffraction combined with theoretical calculations clarify that Te vacancies trigger superconductivity via intrinsic electron doping and the evolution of the Td phase from the 1T′ phase below 200 K. Unlike the pressure-induced superconducting state of monoclinic MoTe2, this Te vacancy-induced superconductivity is emerged in orthorhombic MoTe2, which is predicted as Weyl semimetal, via electron-doping. This chalcogen vacancy induced-superconductivity provides a new route for cultivating superconducting state together with WSM state in 2D van der Waals materials.

Electrospun fibers of poly(l‐lactic acid) containing lovastatin with potential applications in drug delivery

ABSTRACTLovastatin (Merck's Mevacor) is a statin drug designed to lower cholesterol, and reduce the risk of heart attack and stroke. We use electrospinning to combine the biomedical properties of lovastatin with the advantages of electrospun fibers to prepare a composite biomaterial for lovastatin delivery. Poly(l‐lactic acid) (PLLA), a biodegradable and biocompatible polymer, was co‐spun with lovastatin. Incorporation of lovastatin at 5 or 10 wt % improved fiber alignment and surface smoothness, and increased fiber diameter. Influence of lovastatin on the phase structure (crystal, mobile amorphous, and rigid amorphous fractions) was investigated using scanning calorimetry and synchrotron X‐ray scattering. Addition of lovastatin resulted in increased crystallinity and reduced mobile amorphous fraction. PLLA fibers were characterized in terms of their drug release kinetics in comparison to PLLA film. High drug entrapment efficiency (ranging from 72% to 82%) and appropriate release profiles were achieved. In vitro drug release studies demonstrated that release occurred in two stages: an initial rapid release over the first day and a slower second stage of release which approached a plateau after 7 days. PLLA fibers have a higher release rate than comparable film. Electrospun biomaterial fibers of PLLA provide a promising new release strategy for delivery of lovastatin. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45287.

Thoracic vertebral count and thoracolumbar transition in Australopithecus afarensis

The evolution of the human pattern of axial segmentation has been the focus of considerable discussion in paleoanthropology. Although several complete lumbar vertebral columns are known for early hominins, to date, no complete cervical or thoracic series has been recovered. Several partial skeletons have revealed that the thoracolumbar transition in early hominins differed from that of most extant apes and humans. Australopithecus africanus, Australopithecus sediba, and Homo erectus all had zygapophyseal facets that shift from thoracic-like to lumbar-like at the penultimate rib-bearing level, rather than the ultimate rib-bearing level, as in most humans and extant African apes. What has not been clear is whether Australopithecus had 12 thoracic vertebrae as in most humans, or 13 as in most African apes, and where the position of the thoracolumbar transitional element was. The discovery, preparation, and synchrotron scanning of the Australopithecus afarensis partial skeleton DIK-1-1, from Dikika, Ethiopia, provides the only known complete hominin cervical and thoracic vertebral column before 60,000 years ago. DIK-1-1 is the only known Australopithecus skeleton to preserve all seven cervical vertebrae and provides evidence for 12 thoracic vertebrae with a transition in facet morphology at the 11th thoracic level. The location of this transition, one segment cranial to the ultimate rib-bearing vertebra, also occurs in all other early hominins and is higher than in most humans or extant apes. At 3.3 million years ago, the DIK-1-1 skeleton is the earliest example of this distinctive and unusual pattern of axial segmentation.

Chalcopyrite dissolution: Scanning photoelectron microscopy examination of the evolution of sulfur species with and without added iron or pyrite

Dissolution and oxidation of sulfide minerals play key roles in both acid and metalliferous rock drainage and supergene enrichment. Surface speciation heterogeneity, critical to understanding mechanisms of mineral sulfide dissolution, has to date largely not been considered. To this end synchrotron scanning photoelectron microscopy (SPEM) was employed to examine freshly fractured and partially dissolved chalcopyrite (CuFeS2) surfaces (pH 1.0 HClO4 solution, redox potential 650mV relative to a standard hydrogen electrode, 75°C). S2− (bulk), S22− and Sn2− were found to be present on all samples at varying concentrations. Oxidation was observed to take place heterogeneously at the sub-micron scale. As compared to chalcopyrite partially dissolved for 5days, extended dissolution to 10days did not show appreciably enhanced oxidation of surface species; however surface roughness increased markedly due to the growth/overlap of oxidised sulfur species. On addition of 4mM iron both S0 and SO42− were observed but not SO32−, indicating that the greater Fe3+ activity/concentration promotes heterogeneous sulfur oxidation. On contact of pyrite (FeS2) with chalcopyrite, significantly greater chalcopyrite surface oxidation was observed than for the other systems examined, with S0, SO32− and SO42− being identified heterogeneously across the surface. It is proposed that chalcopyrite oxidative dissolution is enhanced by increasing its cathodic area, e.g. contacting with pyrite, while increased Fe3+ activity/concentration also contributes to increased dissolution rates. The high degree of surface heterogeneity of these surface products indicates that these surfaces are not passivated by their formation. These results suggest that chalcopyrite dissolution will be accelerated when in contact with pyrite at solution redox potential intermediate between the rest potentials of chalcopyrite and pyrite (560mV and 660mV, respectively) and/or iron rich acidic waters with resulting enhanced formation of secondary sulfur containing species and release of copper and iron. This in turn suggests accelerated supergene formation and enhanced metalliferous drainage under these conditions.

Characterization of secondary pores in washcoat layers and their effect on effective gas transport properties

It is well known that the performance of monolithic catalysts is limited by gas transport resistance in the washcoat layer. Gases are transported via two types of pores within the washcoat layer: primary pores, which exist inside the particle of catalyst support material (e.g., Al2O3), and secondary pores, which are voids among particles of the catalyst support material. Primary pores play an important role in the effectiveness of catalytically active components such as Pt, Rh, and Pd, while secondary pores facilitate gas transport in the washcoat layer. This paper reports the characterization of secondary pores and their effect on gas transport. In order to evaluate the gas transport properties of a washcoat layer, effective gas permeability was measured. Four samples with different pore morphologies were prepared, and their secondary pore properties were characterized with scanning electron microscopy, mercury porosimetry and synchrotron X-ray computed tomography. The obtained pore properties were correlated with the effective gas permeability, and based on the obtained correlation, we formulated a model for the gas permeability of the pores. This new model was compared to the conventional Kozeny-Carman equation.

Febantel: looking for new polymorphs

The aim of this work was to search for new polymorphic forms of febantel, an anthelminthic drug of great present interest for the veterinary industry. Solvent-based recrystallization, thermal and mechanical treatments and spray drying were chosen to discover new solid forms. The solids obtained were physicochemically characterized by thermal techniques (DSC and TG), FTIR spectroscopy, laboratory and synchrotron X-ray powder diffraction and scanning electron microscopy. Our work leads to obtain a new solid form never described in the literature. In particular, the new polymorph was obtained by the anti-solvent method and the crystallization from isopropanol. The experimental conditions of crystallization favorable to the formation of the highest amount of the new solid phase were selected. The new phase shows a thermal, spectroscopic and diffractometric behavior unique. Furthermore, the preliminary structure investigation suggests two possible crystal systems: an orthorhombic or a monoclinic one, with really comparable lattice parameters and cell volume. Measurements put into evidence that the new phase is a metastable polymorph that is in monotropic relationship with the stable and known form.

Towards a Better Understanding of the Origins of Microlens Arrays in Mesozoic Ophiuroids and Asteroids

Echinoderms are characterized by a calcite endoskeleton with a unique microstructure, which is optimized for multiple functions. For instance, some light-sensitive ophiuroids (Ophiuroidea) and asteroids (Asteroidea) possess skeletal plates with multi-lens arrays that are thought to act as photosensory organs. The origins of these lens-like microstructures have long been unclear. It was recently proposed that the complex photosensory systems in certain modern ophiuroids and asteroids could be traced back to at least the Late Cretaceous (ca. 79 Ma). Here, we document similar structures in ophiuroids and asteroids from the Early Cretaceous of Poland (ca. 136 Ma) that are approximately 57 million years older than the oldest asterozoans with lens-like microstructures described thus far. We use scanning electron microscopy, synchrotron tomography, and electron backscatter diffraction combined with focused ion beam microscopy to describe the morphology and crystallography of these structures in exceptional detail. The results indicate that, similar to Recent light-sensitive ophiuroids, putative microlenses in Cretaceous ophiuroids and asteroids exhibit a shape and crystal orientation that would have minimized spherical aberration and birefringence. We suggest that these lens-like microstructures evolved by secondary deposition of calcite on pre-existing porous tubercles that were already present in ancestral Jurassic forms.

Probing the deformation and fracture properties of Cu/W nano-multilayers by in situ SEM and synchrotron XRD strain microscopy

When thin metallic multilayers deposited on a compliant polymer substrate are subjected to stretching, a “brick wall” fracture pattern arises that is associated with a non-uniform two-dimensional stress-strain state evolving as a function of the underlying substrate stretch. The present study is devoted to in situ mechanical microscopy of strain states in a copper/tungsten 18/6nm multilayer using the combination of synchrotron Scanning X-Ray Diffraction Microscopy (SXDM) and Scanning Electron Microscopy (SEM), coupled with Digital Image Correlation (DIC). We demonstrate that these methods allow spatial variation of the coating strain to be mapped and compared with theoretical predictions based on shear lag theory, allowing the fracture properties of the multilayer to be extracted.

Saportanthus, an Extinct Genus of Laurales from the Early Cretaceous of Portugal

Premise of research. Numerous exquisitely preserved fossil floral structures recovered from Lower Cretaceous sediments in Portugal are invaluable for understanding the organization and structure of flowers at an early stage in angiosperm evolution. This study analyses three such flowers that add significantly to current knowledge of structural and systematic diversity among very early eumagnoliid angiosperms.Methodology. Fossil flowers were extracted from unconsolidated sedimentary rocks by sieving in water. Morphological and anatomical details were studied using scanning electron microscopy and synchrotron radiation X-ray tomographic microscopy. The phylogenetic position of the fossils was assessed using the available morphological data sets for extant taxa.Pivotal results. A new genus, Saportanthus, with three new species, S. brachystemon, S. dolichostemon, and S. parvus, is described from the Early Cretaceous of the Lusitanian Basin, western Portugal, based on coalified flowers. The flowers are small, ...

Deformation mechanisms during severe plastic deformation of a Cu[sbnd]Ag composite

A Cu-37 at%Ag composite was produced by high-pressure torsion processing of elemental Cu and Ag powders at room temperature. The initial micrometer-sized powder particles were compressed directly in the high-pressure torsion tool and subsequently deformed to different strain levels. The microstructural evolution was studied in detail by scanning and transmission electron microscopy and synchrotron X-Ray measurements, and related to the mechanical properties by microhardness and nanoindentation measurements. The HPT process led to an alignment of Cu and Ag into a lamellar composite microstructure. With increasing applied strain the Cu and Ag lamellae were continuously thinned and simultaneously an ultrafine-grained microstructure was formed in the separate Cu and Ag lamellae. When the lamella spacing reached values lower than the respective grain sizes inside the lamellae, a further lamella thinning occurred causing a significant hardness increase of the composite. At lamella spacings below 50 nm deformation started to localize in 150–300 nm broad shear bands, which surprisingly exhibited no softening. Instead, the steady formation of new shear bands aided to transform the lamellar structure into a nanocrystalline equi-axed microstructure and additionally rotated the lamellar matrix towards the shear plane. This process led to an additional refinement of the alloy and a hardness increase until a constant hardness level was obtained. Combined analyses by synchrotron X-ray and transmission electron microscopy measurements revealed that, after reaching the saturation microhardness level, mechanical mixing of Cu and Ag occurred in the shear bands, which can be attributed to the enormous strains accommodated in the shear bands. Due to the localized deformation by shear bands, structural and chemical homogenization of the alloy was not achieved even at very high applied strains. The final microstructure was composed of nanocrystalline single-phase supersaturated regions embedded in a residual nano-lamellar matrix.

Magnetite plaquettes are naturally asymmetric materials in meteorites

Life on Earth shows preference toward the set of organics with particular spatial configurations. Enantiomeric excesses have been observed for α-methyl amino acids in meteorites, which suggests that chiral asymmetry might have an abiotic origin. A possible abiotic mechanism that could produce chiral asymmetry in meteoritic amino acids is their formation under the influence of asymmetric catalysts, as mineral crystallization can produce spatially asymmetric structures. Although magnetite plaquettes have been proposed to be a possible candidate for an asymmetric catalyst, based on the suggestion that they have a spiral structure, a comprehensive description of their morphology and interpretation of the mechanism associated with symmetry-breaking in biomolecules remain elusive. Here we report observations of magnetite plaquettes in carbonaceous chondrites (CC) that were made with scanning electron microscopy and synchrotron X-ray computed microtomography (SXRCT). We obtained the crystal orientation of the plaquettes using electron backscatter diffraction (EBSD) analysis. SXRCT permits visualization of the internal features of the plaquettes. It provides an unambiguous conclusion that the plaquettes are devoid of a spiral feature and, rather that they are stacks of individual magnetite disks that do not join to form a continuous spiral. Despite the lack of spiral features, our EBSD data show significant changes in crystal orientation between adjacent magnetite disks. The magnetite disks are displaced in a consistent relative direction that lead to an overall crystallographic rotational mechanism. This work offers an explicit understanding of the structures of magnetite plaquettes in CC, which provides a fundamental basis for future interpretation of the proposed symmetry-breaking mechanism.

Effect of Phytosterols on the Crystallization Behavior of Oil-in-Water Milk Fat Emulsions.

Milk has been used commercially as a carrier for phytosterols, but there is limited knowledge on the effect of added plant sterols on the properties of the system. In this study, phytosterols dispersed in milk fat at a level of 0.3 or 0.6% were homogenized with an aqueous dispersion of whey protein isolate (WPI). The particle size, morphology, ζ-potential, and stability of the emulsions were investigated. Emulsion crystallization properties were examined through the use of differential scanning calorimetry (DSC) and Synchrotron X-ray scattering at both small and wide angles. Phytosterol enrichment influenced the particle size and physical appearance of the emulsion droplets, but did not affect the stability or charge of the dispersed particles. DSC data demonstrated that, at the higher level of phytosterol addition, crystallization of milk fat was delayed, whereas, at the lower level, phytosterol enrichment induced nucleation and emulsion crystallization. These differences were attributed to the formation of separate phytosterol crystals within the emulsions at the high phytosterol concentration, as characterized by Synchrotron X-ray measurements. X-ray scattering patterns demonstrated the ability of the phytosterol to integrate within the milk fat triacylglycerol matrix, with a concomitant increase in longitudinal packing and system disorder. Understanding the consequences of adding phytosterols, on the physical and crystalline behavior of emulsions may enable the functional food industry to design more physically and chemically stable products.

Interfibrillar packing of bovine cornea by table-top and synchrotron scanning SAXS microscopy.

Bovine cornea was studied with scanning small-angle X-ray scattering (SAXS) microscopy, by using both synchrotron radiation and a microfocus laboratory source. A combination of statistical (adaptive binning and canonical correlation analysis) and crystallographic (pair distribution function analysis) approaches allowed inspection of the collagen lateral packing of the supramolecular structure. Results reveal (i) a decrease of the interfibrillar distance and of the shell thickness around the fibrils from the periphery to the center of the cornea, (ii) a uniform fibril diameter across the explored area, and (iii) a distorted quasi-hexagonal arrangement of the collagen fibrils. The results are in agreement with existing literature. The overlap between laboratory and synchrotron-radiation data opens new perspectives for further studies on collagen-based/engineered tissues by the SAXS microscopy technique at laboratory-scale facilities.

Origin of ambipolar graphene doping induced by the ordered Ge film intercalated on SiC(0001)

Transfer doping mechanism of the quasi-free-standing monolayer graphene (QFMLG), depending on the thickness as well as the atomic structures of the intercalated Ge film, has been revealed by combined investigations of scanning tunneling microscopy and synchrotron photoemission spectroscopy. The ordered Ge film has been formed between QFMLG and the n-type 6H-SiC(0001) substrate by depositing Ge on the (63×63)R30° zero layer and postannealing. At postannealing temperatures lower than 900 °C, the interfacial structures inducing p-type QFMLG, like 2×1.5n3 and 4×33, are formed. On the other hand, at those higher than 900 °C, the interfacial structures inducing n-type QFMLG, like 7×43 [expressed as a (5−376) matrix], 8×33 and 21×21 [expressed as a (5115) matrix], are formed as a result of partial deintercalation of Ge atoms. Such a transition from p-type to n-type doping turns out to be associated with an increase in the density of states of an upper Hubbard band originating from strong correlation of the electrons at the Ge atoms on the first and the second Ge interfacial layers.

A Re-Description of 'Mycterosaurus' smithae, an Early Permian Eothyridid, and Its Impact on the Phylogeny of Pelycosaurian-Grade Synapsids.

‘Mycterosaurus’ smithae, from the Cisuralian (early Permian) of Colorado, was first described in 1965 as a second species of the genus Mycterosaurus. While the type species of this genus, M. longiceps, has been shown by multiple cladistic analyses to belong to the basal synapsid family Varanopidae, ‘M.’ smithae has been largely ignored since its original description. Additional preparation and synchrotron scanning has revealed new significant information that supports the assignment of this species to a new genus: Vaughnictis gen. nov. Vaughnictis lacks many of the characteristics of mycterosaurines and varanopids in general: it lacks the slender femur, the linguo-labially compressed and strongly recurved teeth, and the lateral boss on the postorbital characteristic of this family. Instead, it possesses coronoid teeth, a large supratemporal, and a large pineal foramen positioned midway along the length of the parietal, features that support its assignment to Eothyrididae. Moreover, the postcranium shares many characters with the eothyridid Oedaleops. An expanded version of a recently published phylogenetic analysis of pelycosaurian-grade synapsids positions Vaughnictis as the sister taxon of Eothyris within the clade Eothyrididae. The addition of data on the postcranium of eothyridids and the inclusion of the recently-described basal caseid Eocasea confirms the recently-disputed position of caseasaurs as the most basal synapsids. As the parsimony analysis produced low support values and a lack of resolution due to missing data, additional analyses were undertaken using Bayesian and Implied Weights methods, which produced better resolution and relationships with higher support values. While the results are similar, alternative positions for the enigmatic Moscovian age (Carboniferous) synapsid Echinerpeton are suggested by Bayesian analysis; the parsimony analysis found it to be an ophiacodontid, while the Bayesian and Implied Weights analysis found it to be the sister to the Sphenacomorpha.

Combining operando synchrotron X-ray tomographic microscopy and scanning X-ray diffraction to study lithium ion batteries.

We present an operando study of a lithium ion battery combining scanning X-ray diffraction (SXRD) and synchrotron radiation X-ray tomographic microscopy (SRXTM) simultaneously for the first time. This combination of techniques facilitates the investigation of dynamic processes in lithium ion batteries containing amorphous and/or weakly attenuating active materials. While amorphous materials pose a challenge for diffraction techniques, weakly attenuating material systems pose a challenge for attenuation-contrast tomography. Furthermore, combining SXRD and SRXTM can be used to correlate processes occurring at the atomic level in the crystal lattices of the active materials with those at the scale of electrode microstructure. To demonstrate the benefits of this approach, we investigate a silicon powder electrode in lithium metal half-cell configuration. Combining SXRD and SRXTM, we are able to (i) quantify the dissolution of the metallic lithium electrode and the expansion of the silicon electrode, (ii) better understand the formation of the Li15Si4 phase, and (iii) non-invasively probe kinetic limitations within the silicon electrode. A simple model based on the 1D diffusion equation allows us to qualitatively understand the observed kinetics and demonstrates why high-capacity electrodes are more prone to inhomogeneous lithiation reactions.

In situ crystallization and transformation kinetics of polymorphic forms of saturated-unsaturated-unsaturated triacylglycerols: 1-palmitoyl-2,3-dioleoyl glycerol, 1-stearoyl-2,3-dioleoyl glycerol, and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol

We examined the influence of dynamic thermal treatment (variation of cooling/heating rates) on the polymorphic crystallization and transformation pathways of 1-palmitoyl-2,3-dioleoyl glycerol (POO), 1-stearoyl-2,3-dioleoyl glycerol (SOO), and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol (POL), which are major saturated-unsaturated-unsaturated (SUU) triacylglycerols (TAGs) of vegetable oils and animal fats (e.g., palm oil, olive oil, and Iberian ham fat). Using mainly a combination of differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffraction (SR-XRD), we analyzed the polymorphic behavior of TAGs when high (15°Cmin−1), intermediate (2°Cmin−1), and low (0.5°Cmin−1) cooling and heating rates were applied. Multiple polymorphic forms were detected in POO, SOO, and POL (sub-α, α, β’2, and β’1). Transient disordered phases, defined as kinetic liquid crystal (KLC) phases, were determined in POO and SOO for the first time. The results demonstrated that more stable forms were directly obtained from the melt by decreasing the cooling rates, whereas less stable forms predominated at high cooling rates, as confirmed in our previous work. Regarding heating rate variation, we confirmed that the nature of the polymorphic transformations observed (solid-state, transformation through KLC phase, or melt-mediation) depended largely on the heating rate. These results were discussed considering the activation energies involved in each process and compared with previous studies on TAGs with different saturated-unsaturated structures (1,3-dioleoyl-2-palmitoylglycerol, 1,3-dipalmitoyl-2-oleoyl-glycerol, trioleoyl glycerol, and 1,2-dioleoyl-3-linoleoyl glycerol).

Barite precipitation following celestite dissolution in a porous medium: A SEM/BSE and μ-XRD/XRF study

A reaction cell experiment was designed to examine mineral dissolution/precipitation processes both at the macroscopic and pore scale. A rectangular flow cell was filled with a reactive porous layer lying between two porous layers composed of quartz sand (SiO2). The reactive layer consisted of celestite (or celestine, SrSO4) with a bimodal grain size distribution (<63μm and 125–400μm). A barium chloride solution was then injected into the flow cell, leading to fast dissolution and replacement of celestite by barite (or baryte, BaSO4). Due to the higher molar volume of barite compared to celestite, the porosity decreased in the reactive layer. We concentrated on the refinement of post-mortem analysis and the investigation of the dissolution/precipitation mechanisms at the pore scale (10–100μm). The sequential evolution of mineral transformations occurring in the reactive layer was determined. Our analytical techniques, combining scanning electron microscopy and synchrotron X-ray microdiffraction/microfluorescence, showed that the small celestite grain fraction dissolved rapidly to form nano-crystalline barite filling the pore space, while large celestite grains were covered with a thin rim of epitaxial micro-crystalline barite. Two distinct nucleation mechanisms for barite precipitation were involved: homogeneous nucleation (nucleation of barite in the pore space) and heterogeneous nucleation (nucleation on the surface of a solid substrate). Classical nucleation theory, using well-established and estimated parameters (e.g. effective interfacial tension) describing barite nucleation, was applied to explain the mineralogical changes occurring in our system.

Sub/fossil resin research in the 21st Century: trends and perspectives

Within the last few decades technological advances such as the Internet and new imaging techniques (e.g., computed tomography and synchrotron scanning) have revolutionized how we do research in the 21st century. High-quality publications resulting from international, interdisciplinary collaborations are now commonplace, though there is still much scope for improvement in certain branches of amber palaeobiology. Here, I review what I consider to be some of the most important trends in amber research over the past decade or so and highlight areas deserving of more focussed input. Topics covered include summaries of our current knowledge of palaeodiversity of the major world deposits, important new Cenozoic and Mesozoic amber deposits, palaeo-taxonomy (and over-interpretation of fossil inclusions), advances in imaging technologies, quantitative palaeoecology, and climate change and biogeography. The potential scientific value of inclusions in copal, a source of sub-fossils that is often considered unimportant due to its relatively young age, is also briefly discussed.

Characterization of cosmetic sticks at Xiaohe Cemetery in early Bronze Age Xinjiang, China.

Cosmetics have been studied for a long time in the society and culture research, and its consumption is regarded as a cultural symbol of human society. This paper focuses on the analysis of the red cosmetic sticks, found in Xiaohe Cemetery (1980–1450BC), Xinjiang, China. The structure of the red cosmetic sticks was disclosed by SR-μCT scanning (Synchrotron Radiation Micro-computed Tomography), while the chemical components were characterized by FTIR (Fourier Transform Infrared Spectroscopy), Raman Spectroscopy and Proteomics. The results suggested that the cosmetic sticks were made from the cattle heart and covered with a layer of hematite powders as the pigment. Given the numerous red painted relics in Xiaohe Cemetery, this kind of cosmetic sticks might be used as a primitive form of crayon for makeup and painting. The usage of cattle hearts as cosmetic sticks is firstly reported up to our knowledge, which not only reveals the varied utilizations of cattle in Xiaohe Cemetery but also shows the distinctive religious function. Furthermore, these red cosmetic sticks were usually buried with women, implying that the woman may be the painter and play a special role in religious activities.