Prehistoric technology Ground and polished stone tools continued to be created and used during the Neolithic period. Numeric record keeping evolved from a system of counting using small clay tokens that began in Sumer about 8000 BC. The Stone Age developed into the Bronze Age after the Neolithic Revolution. The Neolithic Revolution involved radical changes in agricultural technology which included development of agriculture, animal domestication, and the adoption of permanent settlements. The Bronze Age is characterised by metal smelting of copper and its alloy bronze, an alloy of tin and copper, to create implements and weapons. Polished stone tools continued to be
Antimicrobial copper-alloy touch surfaces surfaces typically manufactured with standard materials (i.e., plastic, chrome, aluminum) were replaced with copper alloys. These included a copper alloy set of sink tap handles (60% Cu, 40% Zn) and a ward entrance door push plate (70% Cu, 30% Zn). Contamination reductions of 90–100% were observed for "Staphylococcus aureus", "Escherichia coli", "Klebsiella pneumoniae", "Acinetobacter baumanii", "Enterococcus" spp., and "Candida albicans" on the copper alloy surfaces versus the non-copper standard surfaces. A microorganism reduction of 100% was observed on the hot tap copper alloy handle. The high degree of clinical performance suggested that copper alloy surfaces may increase the effectiveness of