Organic residue analysis reveals the function of bronze age metal daggers.

The article discusses results of organic residue analysis performed on ten copper-alloy daggers from Bronze Age Pragatto, Italy, c.1550-1250 BCE. Metal daggers are widespread in Chalcolithic and Bronze Age Europe, yet their social and practical roles are still hotly debated. Are they symbolic or functional? Are they tools or weapons? How were they used? For what tasks and on what materials? The research addresses these questions through a novel application of biochemical staining and SEM-EDX analysis. The method has proved successful in extracting and identifying animal residues located on cutting edges including bone, muscle, and tendons. These are interpreted as evidence of prehistoric carcass butchering and carving. Further residues were observed on blade faces and hafting plates or tangs; these are interpreted as remnants of bone handles and sheaths, the latter made of either wood fibers or processed hide and fur. The readings proposed in the article are validated by original experiments with replica daggers, as detailed in the Supplementary Materials. The analysis and experiments shed new light on Bronze Age metal daggers, showing that they were fully functional tools (and perhaps tool-weapons) primarily utilized for the processing of animal carcasses. This original research result contributes significant knowledge towards interpreting an under-studied, yet socially salient, prehistoric metal artifact.

Synthesis and Characterisation of Reduced Graphene Oxide/Bismuth Composite for Electrodes in Electrochemical Energy Storage Devices.

A reduced graphene oxide/bismuth (rGO/Bi) composite was synthesized for the first time using a polyol process at a low reaction temperature and with a short reaction time (60 °C and 3 hours, respectively). The as-prepared sample is structured with 20-50 nm diameter bismuth particles distributed on the rGO sheets. The rGO/Bi composite displays a combination of capacitive and battery-like charge storage, achieving a specific capacity value of 773 C g-1 at a current density of 0.2 A g-1 when charged to 1 V. The material not only has good power density but also shows moderate stability in cycling tests with current densities as high as 5 A g-1 . The relatively high abundance and low price of bismuth make this rGO/Bi material a promising candidate for use in electrode materials in future energy storage devices.

Crevice corrosion of implants recovered after tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To describe corrosion discovered on implants recovered from dogs after tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Descriptive. ANIMALS: Dogs (n=4) that had TPLO (n=7) approximately 3 years earlier. METHODS: Implants were recovered surgically and lightly cleaned before visual inspection, scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). RESULTS: Multiple corrosion sites were found on the recesses of each plate; invariably, there was a corroded area present on that part of the bone screw which had been in contact with a corrosion site on a plate. Most corroded regions featured attached, nonmetallic material believed to be a precipitate arising from interaction with the local environment during electrochemical corrosion. SEM examination of TPLO plates revealed surface porosity, particularly visible in the screw hole recesses. CONCLUSIONS: Surface irregularities and porosity of TPLO plates--a consequence of the casting process--are initiation sites for corrosion which, in concert with the crevice geometry between the plate and screw, result in the observed corrosion defects. CLINICAL RELEVANCE: Implants used for TPLO, a commonly performed veterinary orthopedic procedures may corrode generating a number of chemical species that have the potential to cause disease.