Forager-farmer transition at the crossroads of East and Southeast Asia 4900 years ago.

The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture. However, the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence. Here we report macrofossil, microfossil, multiple isotopic (C/N/Sr/O) and paleoproteomic data directly from radiocarbon-dated human samples, which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP. Dietary isotopes reveal the earliest arrival of millet ca. 4900 a BP, and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP. The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains. The results of paleoproteomic analysis indicate that humans had divergent biological adaptations, with and without farming. The combined application of isotopes, archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.

Earliest systematic coal exploitation for fuel extended to ~3600 B.P.

Coal has long fueled human civilizations. The history of systematic coal fuel exploitation has been traced back to the late third millennium before present (post-2500 B.P.). Although sporadic combustion of coal for fuel was reported in some prehistoric archaeological sites, evidence for the systematic exploitation of coal for fuel before 2500 B.P. remains lacking. Here, we report comprehensive understanding for the earliest systematic exploitation of coal for fuel at the Jirentaigoukou site in Xinjiang, northwestern China, at ~3600 B.P. The main body of the site witnessed systematic exploitation of bituminous coals, illustrating a complete chaîne opératoire with selective mining, planned storage, and extensive combustion. Our results transform the knowledge of energy history by extending the upper limit of the systematic exploitation of coal for fuel by approximately a millennium, and provide a precedent of energy transition under intense conflict between social demand and environmental deterioration.

Human migration in the eastern Tianshan Mountains between the 7th and 12th centuries.

OBJECTIVE: Mid- to late-Holocene large-scale population migration profoundly impacted the interaction of ethnic groups and cultures across Eurasia, notably in Central Asia. However, due to a lack of thorough historical documents, distinctive burial items, and human remains, the process of population migration during this historical era in the area is still unclear. Using an interdisciplinary approach at the Lafuqueke (LFQK) cemetery, this study investigates the spatiotemporal processes and explores the factors that influenced human migration in the eastern Tianshan Mountains between the 7th and 12th centuries. MATERIALS AND METHODS: In this study, tooth enamel from 56 human remains found in the LFQK cemetery in Hami Basin, eastern Tianshan Mountains, is examined for strontium and lead isotopes. RESULTS: The early, middle, and late phases of migration might potentially be represented by a three-phase migration model, according to the isotopic study. The highest proportion of the early phase (ca. 7th-mid 7th century) comprised non-locals (54.55%), although this percentage decreased in the middle phase (mid 7th-mid 8th centuries, 30.77%). After the 10th century, the proportion of non-locals again fell (16.13%). CONCLUSION: In this study, the interdisciplinary approach was employed to propose a new model for the diachronic changes that accompanied human migration and cultural interaction in the eastern Tianshan Mountains and identified geopolitics as a significant factor influencing the migratory behavior of LFQK population in this region between the 7th and 12th centuries.

The lifestyle of Tuyuhun royal descendants: Identification and chemical analysis of buried plants in the Chashancun cemetery, northwest China.

The Tuyuhun Kingdom (AD 313-663) was one of the most famous regimes in northwest China during the early medieval period. However, the lifestyle and spiritual pursuit of their descendants who became allied with the Tang Dynasty remain enigmatic. The excavation of the Chashancun cemetery, a Tuyuhun royal descendant (AD 691) cemetery in the Qilian Mountains in northwest China, reveals a large amount of uncharred plant remains. These remains provided a rare opportunity to explore the geographical origin of the buried crops and their social implications. In total, 253,647 crops and 12,071 weeds were identified. Foxtail millet and broomcorn millet represent 61.99 and 30.83% of the total plant remains, with the rest being barley, buckwheat, beans, and hemp. The oxygen isotope and trace elements of the crop and weed remains suggest that broomcorn millet, foxtail millet, barley, buckwheat, and hemp were sourced from different regions. The assemblage of plant remains in the Chashancun cemetery suggests that millet cultivation played an important role in the livelihoods of Tuyuhun descendants, and the location of the elite Tuyuhun cemetery and multisources of different buried crops may reflect their memory of ancestors and homelands. This case study provides a unique perspective to understand the interactions among human subsistence strategy, geopolitical patterns, and local natural environments in northwest China during the late 7th century.

New scientific analyses reveal mixing of copper sources in the early Iron Age metal production at Ili, western China.

The crucial role that Xinjiang played in cultural communication across the Eurasian steppe in prehistory is evidenced by the large number of copper-based objects that represent the early metallurgical technologies found across this region. Our research adds new chemical and isotopic analyses of 44 copper-based objects dated to the early Iron Age of Ili in Xinjiang, western China. As noted in a number of publications, tin bronze and arsenic copper/bronze were the dominant alloying types across Xinjiang during the second and first millennium BC, whereas some specific types of objects such as cauldrons are often made from pure copper. The western Tianshan Mountain, including the well-known mining site Nulasai, is the most likely copper source for the Ili metalworking. Meanwhile, a combination of lead isotopes, lead concentrations and trace elemental data reveals new evidence for the mixing and recycling of different sources of copper.

'Nothing new under the sun': Rethinking recycling in the past- Editorial.

Editorial for the Special Issue of Archaeometry 'Tackling Recycling in the Past'. The practice of recycling has undoubtedly become one of the most important strategies to build a long-term sustainable society in the modern world. However, both the perception and practice of recycling can be traced back to prehistory through various archaeological records. Objects made of stone, jade, mortar, textiles, pottery and bones display evidence of physical reshaping and repair, as do objects of metal and glass. Metal and glass, moreover, are materials which can be melted and recast, freeing ancient people from the limitations of the physical form of the original object. Illustrating and understanding patterns of recycling and the underlying social organization can significantly advance our knowledge of ancient people, their economic, political and cultural motivations for recycling, as well as the broad interaction between the social and material world. Though the issue of recycling is not novel in the discussions and debates of the archaeological circle, new theoretical frameworks, methodologies and archaeometric data encourage us to revisit the topic in this special issue. In this editorial, we consider what recycling means in the past, and why these papers are vital.

Protocol to predict mechanical properties of multi-element ceramics using machine learning.

Identifying and designing high-performance multi-element ceramics based on trial-and-error approaches are ineffective and expensive. Here, we present a machine-learning-accelerated method for prediction of mechanical properties of multi-element ceramics, based on the density functional theory calculation database. Specific bonding characteristics are used as highly efficient machine learning descriptors. This protocol describes a low-cost, high-efficiency, and reliable workflow for developing advanced ceramics with superior mechanical properties. For complete details on the use and execution of this protocol, please refer to Tang et al. (2021).

Megadrought and cultural exchange along the proto-silk road.

Arid Central Asia (ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean. Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hydroclimatic changes on trans-Eurasian cultural exchange. Here, we reconstruct precipitation changes in ACA, covering the mid-late Holocene with a U-Th dated, ~3 a resolution, multi-proxy time series of replicated stalagmites from the southeastern Fergana Valley, Kyrgyzstan. Our data reveal a 640-a megadrought between 5820 and 5180 a BP, which likely impacted cultural development in ACA and impeded the expansion of cultural traits along oasis routes. Instead, it may have diverted the earliest transcontinental exchange along the Eurasian steppe during the 5th millennium BP. With gradually increasing precipitation after the megadrought, settlement of peoples in the oases and river valleys may have facilitated the opening of the oasis routes, "prehistoric Silk Roads", of trans-Eurasian exchange. By the 4th millennium BP, this process may have reshaped cultures across the two continents, laying the foundation for the organized Silk Roads.

Social hierarchy and the choice of metal recycling at Anyang, the last capital of Bronze Age Shang China.

Anyang, the last capital of the Chinese Shang dynasty, became one of the largest metal consumers in Eurasia during the second millennium BCE. However, it remains unclear how Anyang people managed to sustain such a large supply of metal. By considering the chemical analysis of bronze objects within archaeological contexts, this paper shows that the casting and circulation of metal at Anyang was effectively governed by social hierarchy. Objects belonging to the high elites such as Fuhao, particularly the bronze ritual vessels, were made by carefully controlled alloying practice (primary) using very pure copper, whereas the lower elites only had access to bronzes made by secondary alloying practice and copper with more impurities. Such contrasts allow scholars to identify those objects which are less likely to have been made by mixing and recycling, which has very important implications for the chemical and isotopic determination of provenance for future studies.

Improving in vitro and in vivo antibacterial functionality of Mg alloys through micro-alloying with Sr and Ga.

Despite of technical advancements in design and development of new biomaterials, device-related infections continue to occur and can be life-threatening. Differing from existing research work pertaining to introducing antibacterial function upon device surface, this study attempts to address such germ-infection issues through controlled release of antibacterial species from bulk gallium (Ga) and strontium (Sr) containing magnesium (Mg) alloys. To validate such a conceptual framework, Mg alloys containing micro-level concentrations of Ga and/or Sr (0.1 wt%) are employed as model materials, along with commercially pure Mg and titanium (Ti) as control groups. Biodegradation progress of such metal specimens is examined through pH and mass loss measurements, and inductively coupled plasma - atomic emission spectrometry (ICP-AES) as a function of immersion time in Trypticase Soy Broth (TSB) solution under physiological conditions. In vitro biocompatibility and antibacterial performance are characterised through MTT proliferation assay with human mesenchymal stem cells (hMSCs) and the spread plate method with three representative bacterial strains, i.e. S. aureus (ATCC 43300), E. coli (ATCC 25922), and S. epidermidis (ATCC 35984). Animal tests are performed through implanting target metal rods into femurs of Sprague Dawley rats, accompanied with injection of S. aureus to build a model of osteomyelitis. Results demonstrate that such lean additions of Ga and/or Sr reduce the degradation kinetics of Mg matrix, and the release of Ga3+ ions plays a crucial role in disabling the viability of all selected bacterial strains. The histological tests confirm that the growth of fibrous tissue has been accelerated in the vicinity of Mg-based implants, in comparison to that of blank and c.p. Ti controls. It is also striking that the smallest number density of S. aureus bacteria on the surface of the retrieved Ga-containing Mg rod implants. Such a proof-of-concept study provides a new and feasible strategy to address the notorious device-infection issues associated with biomedical implants for bone fracture management.

Beyond ritual bronzes: identifying multiple sources of highly radiogenic lead across Chinese history.

One of the greatest enigmas in the study of Bronze Age China is the source of highly radiogenic lead discovered in the copper-based objects of the Shang period (ca. 1500-1046 BC). Although being relatively rare in nature, such lead contributed over half of the lead consumed across a vast area from the Yellow River to the Yangtze. Identifying its source and supply network would significantly contribute to our understanding of how China achieved the largest metal production across Eurasia. The past thirty years of research have seen various proposals for the origin of this lead, including south-western China, the middle Yangtze River valley, the Qinling and Zhongtiao mountains, and even Africa. This paper attempts to illustrate the tempero-spatial pattern of this highly radiogenic lead using the largest possible databank. Furthermore, by going beyond the bronze data and investigating lead isotopes in non-metal objects, we confirm that multiple sources of highly radiogenic lead must have been used across Chinese history. In turn, this implies the feasibility of a multi-source model for the lead in the Shang bronzes.

Tannin extraction pretreatment and very high gravity fermentation of acorn starch for bioethanol production.

The bioethanol production from a novel non-grain feedstock, acorn starch, was studied in this work. The inhibition of tannin in strain growth was investigated, and the effect of tannin was negligible when the tannin concentration was lower than 1g/L in medium. Therefore, the extraction of tannin was performed using 40% (v/v) ethanol-water solution as the solvent for three times under the conditions of solid/liquid ratio 1:20, 60°C, 3h, by which more than 80% of tannin in acorn was extracted and the content of tannin in acorn decreased from 7.4% (w/w) to 1.5% (w/w). Very high gravity (VHG) fermentation technology was subsequently carried out to achieve a high ethanol concentration at 86.4g/L. A comprehensive process for bioethanol production from acorn starch was designed and a preliminary economic assessment was then performed revealing that this process appeared technically and economically justified.