851 research outputs found

    Variation in enamel mechanical properties throughout the crown in catarrhine primates.

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    Enamel mechanical properties vary across molar crowns, but the relationship among mechanical properties, tooth function, and phylogeny are not well understood. Fifteen primate lower molars representing fourteen taxa (catarrhine, n = 13; platyrrhine, n = 1) were sectioned in the lingual-buccal plane through the mesial cusps. Gradients of enamel mechanical properties, specifically hardness and elastic modulus, were quantified using nanoindentation from inner (near the enamel-dentine junction), through middle, to outer enamel (near the outer enamel surface) at five positions (buccal lateral, buccal cuspal, occlusal middle, lingual cuspal, lingual lateral). Cuspal positions had higher mechanical property values than lateral positions. Middle enamel had higher mean hardness and elastic modulus values than inner and outer locations in all five crown positions. Functionally, the thicker-enameled buccal cusps of lower molars did not show evidence of increased resistance to failure; instead, lingual cusps-which show higher rates of fracture-had higher average mechanical property values, with no significant differences observed between sides. Preliminary phylogenetic results suggest there is relatively little phylogenetic signal in gradients of mechanical properties through the enamel or across the crown. There appears to be common mechanical property patterns across molar crowns in Catarrhini and potentially among primates more broadly. These results may allow more precise interpretations of dental biomechanics and processes resulting in mechanical failure of enamel in primates, such as wear and fracture. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.

    A scientific and archaeological investigation of prehistoric glasses from Italy

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    Ancient glasses are invariably complex materials, in which the specific chemical composition and microstructure capture aspects of their technologies. The chemical characterisation of glasses in specific archaeological contexts has given useful insight into the peculiarities of diverse glass-making technologies. In addition such studies generate more general information upon an important range of phenomenon, including the pyrotechnological milieu, empirical knowledge of sophisticated chemistry, organisation of production, access to significant raw materials and long-distance trade. This study examines a wide selection of glass artefacts recovered from archaeological contexts in Northern and Central Italy from approximately 1200 BC to 200 BC. The earliest material is from the Final Bronze Age, and extends the characterisation of an established glass type, which is unique to Europe and distinct from the contemporary technologies of the Eastern Mediterranean. Using a combination of X-ray fluorescence analysis, electron microprobe and scanning electron microscopy glass artefacts from a thousand-year period from the same region are investigated. The shifting technologies permit the discussion of localised production and importation of glass from elsewhere. The chemical analysis reveals a complex picture of glass production, which defies the expected pattern, and there is evidence for new compositional types, which may yet prove to be diagnostic of highly localised production. The changing compositions are discussed in relation to the broader archaeological context

    A critical role for the loop region of the basic helix–loop–helix/leucine zipper protein Mlx in DNA binding and glucose-regulated transcription

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    The carbohydrate response element (ChoRE) is a cis-acting sequence found in the promoters of genes induced transcriptionally by glucose. The ChoRE is composed of two E box-like motifs that are separated by 5 bp and is recognized by two basic helix–loop–helix/leucine zipper (bHLH/LZ) proteins, ChREBP and Mlx, which heterodimerize to bind DNA. In this study, we demonstrate that two ChREBP/Mlx heterodimers interact to stabilize binding to the tandem E box-like motifs in the ChoRE. Based on a model structure that we generated of ChREBP/Mlx bound to the ChoRE, we hypothesized that intermolecular interactions between residues within the Mlx loop regions of adjacent heterodimers are responsible for stabilizing the complex. We tested this hypothesis by preparing Mlx variants in which the loop region was replaced with that of another family member or mutated at several key residues. These Mlx variants retained their ability to bind to a single perfect E-box motif as a heterodimer with ChREBP, but no longer bound to the ChoRE nor supported glucose responsive activity. In summary, our results support a model in which the loop regions of Mlx play an important functional role in mediating the coordinate binding of ChREBP/Mlx heterodimers to the ChoRE

    A scientific and archaeological investigation of prehistoric glasses from Italy

    Get PDF
    Ancient glasses are invariably complex materials, in which the specific chemical composition and microstructure capture aspects of their technologies. The chemical characterisation of glasses in specific archaeological contexts has given useful insight into the peculiarities of diverse glass-making technologies. In addition such studies generate more general information upon an important range of phenomenon, including the pyrotechnological milieu, empirical knowledge of sophisticated chemistry, organisation of production, access to significant raw materials and long-distance trade. This study examines a wide selection of glass artefacts recovered from archaeological contexts in Northern and Central Italy from approximately 1200 BC to 200 BC. The earliest material is from the Final Bronze Age, and extends the characterisation of an established glass type, which is unique to Europe and distinct from the contemporary technologies of the Eastern Mediterranean. Using a combination of X-ray fluorescence analysis, electron microprobe and scanning electron microscopy glass artefacts from a thousand-year period from the same region are investigated. The shifting technologies permit the discussion of localised production and importation of glass from elsewhere. The chemical analysis reveals a complex picture of glass production, which defies the expected pattern, and there is evidence for new compositional types, which may yet prove to be diagnostic of highly localised production. The changing compositions are discussed in relation to the broader archaeological context

    'Sly grog' and 'homebrew': a qualitative examination of illicit alcohol and some of its impacts on Indigenous communities with alcohol restrictions in regional and remote Queensland (Australia)

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    Background: Indigenous communities in Queensland (Australia) have been subject to Alcohol Management Plans since 2002/03, with significant penalties for breaching restrictions. 'Sly grog' and 'homebrew' provide access to alcohol despite restrictions. This paper describes how this alcohol is made available and the risks and impacts involved. In affected towns and communities across a large area of rural and remote Queensland, interviews and focus groups documented experiences and views of 255 long-standing community members and service providers. Using an inductive framework, transcribed interviews were analysed to identify supply mechanisms, community and service provider responses and impacts experienced. Results: 'Homebrew' was reportedly manufactured in just a few localities, in locally-specific forms bringing locally-specific harms. However, 'sly grog' sourced from licensed premises located long distances from communities, is a widespread concern across the region. 'Sly grog' sellers circumvent retailers' takeaway liquor license conditions, stockpile alcohol outside restricted areas, send hoax messages to divert enforcement and take extraordinary risks to avoid apprehension. Police face significant challenges to enforce restrictions. On-selling of 'sly grog' appears more common in remote communities with total prohibition. Despite different motives for involvement in an illicit trade 'sly grog' consumers and sellers receive similar penalties. Conclusions: There is a need for: (a) a more sophisticated regional approach to managing takeaway alcohol sales from licensed suppliers, (b) targeted penalties for 'sly grog' sellers that reflect its significant community impact, (c) strategies to reduce the demand for alcohol and (d) research to assess the effects of these strategies in reducing harms.Michelle S. Fitts, Jan Robertson, Simon Towle, Chris M. Doran, Robyn McDermott, Adrian Miller, Stephen Margolis, Valmae Ypinazar and Alan R. Cloug
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