Evaluating sources of variation in the identification of linear hypoplastic defects of enamel: a new quantified method

Assessment and interpretation of the presence of developmental defects of enamel formation that result from childhood experiences of growth disruption, enamel hypoplasia, is a standard part of almost any systematic bioarchaeological assessment. However, different identification methods lead to different results. This study presents a new method of defect identification that offers a quantitative criterion for establishing defect presence rather than relying solely on observer judgement. It then compares this with a standard field approach to assessing enamel hypoplasia and a non-quantified microscopic approach in order to determine (a) if traditional methods of identifying enamel hypoplasia under little or no magnification offer the same information about the experience of childhood health as methods that examine dental enamel growth microscopically, and (b) the effect of using a quantified criterion to identify enamel hypoplasia. A case study using simultaneously developing teeth in one individual is presented where observations of defect presence are made both macroscopically and microscopically and with and without this novel metric method. The results demonstrate that the chosen scale of observation is a critical variable in identifying linear hypoplastic defects of enamel. Defects that occur in the more cervical regions of a tooth are ‘missed’ by methods that rely on macroscopic observation or the unaided visual judgement of the observer. This finding has considerable implications for the interpretation of reported enamel hypoplasia prevalence.     

Reconstructing faunal migrations using intra-tooth sampling and strontium and oxygen isotope analyses: a case study of modern caribou (Rangifer tarandus granti)

Isotopic analyses of incrementally developed dental tissues can be used to reveal patterns of movement and diet in animals. However, the suitability of these methods for the reconstruction of herd movements has not yet been demonstrated. Inter-individual behavioural and isotopic variability at the herd scale, and the implications for archaeological and palaeocological applications, can only be demonstrated through the testing of modern animals. In this pilot study, dual-element isotopic profiles were created from incrementally developed dental tissues of five individuals selected from a modern herd of migratory Alaskan caribou (Rangifer tarandus granti). Enamel from second and third molars from the individuals was sequentially sampled in order to reconstruct time-series isotopic profiles. Variation in the strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (δ¹⁸O_CARB) isotope ratios of sequentially sampled enamel were compared to documented herd movement patterns and local geological and environmental conditions. Four individuals displayed the same general trends, although absolute isotopic values varied. One individual displays a very different trend and may represent a behavioural outlier or an immigrant from a semi-domesticated reindeer herd. The implications of this study to herd movement reconstruction in the past are discussed.     

Extraction and sequencing of human and Neanderthal mature enamel proteins using MALDI-TOF/TOF MS

We report here the first results of a method to extract and sequence mature enamel proteins from modern human and Neanderthal tooth enamel. Using MALDI-TOF/TOF mass spectrometry and a combination of direct sequencing and peptide mass mapping we have sequenced a peptide from the tyrosine-rich amelogenin peptide (TRAP) of the X isoform of the amelogenin protein for modern and recent human samples. We also report our results from two Neanderthal enamel samples where we were also able to recover fragments of the TRAP protein, which had a similar sequence to the modern human samples.     

陕西、河南地区出土唐代釉陶器釉层剥离原因分析

釉陶器在埋藏过程中,受物理及化学等因素的影响,会产生各种病害,釉层剥离是常见的病害之一。为了更深入地了解唐代釉陶器釉层剥离的原因并为以后的保护提供科学依据,对陕西、河南地区四个遗址出土的唐代釉陶器样品进行了显微观察、成分检测、热膨胀系数分析和吸水率测试。结果显示,四个遗址中,釉面保存相对完整且剥离现象较少的是巩县黄冶窑,而铜川黄堡窑、西安醴泉坊窑和乾县懿德太子墓釉陶器釉层剥离较为严重。进一步研究表明,釉陶器胎釉热膨胀系数不匹配和胎体烧结程度过低(因此造成吸水率过高)是影响釉陶器釉层剥离的主要内在因素。研究结果可为釉陶器的后续保护工作奠定基础。     

Glass gilding process in medieval Syria and Egypt (13th–14th century)

Twelve gilded and enamelled Islamic glass fragments, produced in Syria or Egypt during the Ayyubid or Mamluk period, were provided by the Louvre museum for complete non-destructive analysis. The enamelling process of similar objects has been extensively studied in the last decades, but the gilding process has never been investigated in details. This paper focuses on the understanding of both the gilding process and the gold/glass adhesion mechanism. The structure, composition and thickness of the gold flakes forming the gilding decoration are measured. The complete process combining gilding and enamelling is described and the local mechanism of adhesion of gold flakes on the glass body is discussed.     

Developmental defects and postmortem changes in archaeological pig teeth from Fais Island,Micronesia

The study investigated developmental defects of the dental hard tissues and postmortem changes in archaeological pig molars from Fais Island, Micronesia. The developmental defects of enamel were indicative of a disturbance of the secretory stage (accentuation of the incremental pattern, occurrence of Wilson bands and of hypoplastic defects) and the maturation stage of amelogenesis (hypomineralisation). Presence of coronal cementum in an M₃ indicated a partial premature breakdown of the reduced enamel epithelium or a partial demise of the enamel organ earlier during tooth development. Developmental defects of dentine presented as accentuated Andresen lines and areas of interglobular dentine. The pattern of developmental defects in the studied molars and the fact that deciduous premolars of the pigs from Fais did not exhibit developmental defects on macroscopic inspection are consistent with the hypothesis that the tooth defects were caused by periods of severe nutritional stress occurring after weaning. Postmortem changes caused by microbial infiltration were recorded in dentine and cementum. A presumed case of soft tissue preservation in the form of presence of odontoblast processes was observed in an M¹.     

Calving seasonality at Pool,Orkney during the first millennium AD: an investigation using intra-tooth isotope ratio analysis of cattle molar enamel

The identification of dairying is essential if we are to understand economies of the past, particularly in northwest Europe, where a high degree of lactose tolerance suggests that fresh milk has long been a significant food product. This paper explores a possible link between economic focus and seasonality of calving. Although cattle (Bos taurus) can breed throughout the year, animals living in temperate regions with minimal or no human management tend to breed seasonally, their breeding behaviour being strongly influenced by the availability of food. In order to achieve a year-round supply of fresh milk in the past, it is likely that multiple-season calving was necessary, which would have required additional husbandry effort. Alternatively, for meat-focussed economies or those based on storable dairy products, a strategy of single-season calving in spring may have been favoured to maximise the utilisation of spring and summer vegetation. Cattle birth seasonality is investigated through isotope ratio analysis (δ¹⁸O, δ¹³C) of tooth enamel. Results for cattle from Pool, Orkney dating to the latter part of the first millennium AD suggest that calving occurred during at least three seasons implying that the continuous provision of fresh milk was of economic importance.     

Residential mobility and social identity in the periphery: strontium isotope analysis of archaeological tooth enamel from southeastern Arabia

Strontium isotope analysis represents an effective means of assessing mobility and reconstructing geographic residence patterns in archaeological populations. This biogeochemical technique was utilized to test the hypothesis that burgeoning interregional exchange networks and the occurrence of exotic grave goods in local tombs would correspond with a highly mobile population and a considerable immigrant presence during the Umm an-Nar (2700–2000 BC) period in the UAE. This region has been considered peripheral relative to larger civilizations in Mesopotamia and the Indus Valley, but played an important role as a major supplier of copper for the Persian Gulf. Individuals (n = 100) from six monumental Umm an-Nar tombs (Mowaihat; Tell Abraq; Umm an-Nar Island I, II, V; Unar 1) were selected to evaluate the geographic origins of tomb members. Mean ⁸⁷Sr/⁸⁶Sr ratios from local individuals interred at Mowaihat (0.708863 ± 0.000014; 1σ, n = 12), Tell Abraq (0.708873 ± 0.000020; 1σ, n = 27), Umm an-Nar Island (0.708902 ± 0.000079; 1σ, n = 33), and Unar 1 (0.708805 ± 0.000065; 1σ, n = 25) all display little isotopic variability, indicative of a population that was not highly mobile. However, coupled with archaeological evidence, three immigrants from Tell Abraq (n = 2) and Mowaihat (n = 1) identified by deviant strontium values suggest that this region was actively engaged in interregional interaction. Despite claims that these tombs acted as visible markers of territoriality legitimized by local ancestors buried within them, the presence of non-locals suggests that as commerce became increasingly important, definitions of kinship and social identity may have become more flexible to better meet the needs of the local community and those with whom they interacted.     

Isotopic analysis of the ecology of herbivores and carnivores from the Middle Pleistocene deposits of the Sierra De Atapuerca,northern Spain

Carbon and oxygen isotope values reveal resource partitioning among the large mammal fauna from three contemporaneous Middle Pleistocene hominid-bearing localities within the Sierra de Atapuerca (northern Spain). Carbon isotope values sampled from the tooth enamel of fauna present during Atapuerca Faunal Unit 6 show that a C₃-dominated ecosystem surrounded the area where fossils were preserved during this time. For the herbivores, Fallow deer isotope values are significantly different from Red deer and horses and show that this species did not forage in open environments at this locality. Red deer and horses show similar feeding strategies with less negative carbon values implying use of more open environments for these taxa. For the carnivores, carbon isotope values for Ursus deningeri are significantly different from either lions (Panthera leo) or foxes (Vulpes vulpes) and support the contention that this species is herbivorous. Special metabolic mechanisms involved in hibernation in U. deningeri might also have influenced its isotope values. The carbon isotope values of remaining carnivores were similar and suggest that each was typically a generalist carnivore, eating a wide variety of prey items. While the isotopic results generally correspond to ecology indicated by previous techniques, this study shows that isotope analyses can provide further insights that alternate techniques do not provide. Isotope analyses can help elucidate the ancient ecology of taxa present in the Sierra de Atapuerca during the Middle Pleistocene allowing for an accurate portrayal of the setting in which humans lived.     

故宫博物院藏一件景泰款掐丝珐琅器的科学分析

本工作以X射线计算机断层扫描(X-CT)成像技术为主要研究手段对故宫博物院藏一件景泰款掐丝珐琅器进行了结构工艺上的研究,结合X射线荧光光谱仪的元素分析和拉曼光谱仪的特征拉曼光谱佐证,发现此件珐琅器不同部位如口沿、耳部、颈部、腹部、底足均来自不同的器物。结果显示釉层厚度、釉料颜色、结构关系以及元素成分含量趋势之间的对应关系可互相验证并吻合,明确了此件珐琅器为后期拼配的改制器。本工作应用X-CT成像技术和X射线荧光(XRF)光谱技术对景泰款珐琅器的研究结果科学化、可视化地证实了以前专家学者靠观测得出的推论。