Tin allowed for the much more complex shapes cast in closed moulds of the Bronze Age. Arsenical bronze objects appear first in the Near East where arsenic is commonly found in association with copper ore, but the health risks were quickly realized and the quest for sources of the much less hazardous tin ores began early in the Bronze Age. This created the demand for rare tin metal and formed a trade network that linked the distant sources of tin to the markets of Bronze Age cultures. Cassiterite (SnO), the tin oxide form of tin, was most likely the original source
Antimicrobial copper-alloy touch surfaces University Hospital in Manhasset, New York. An alloy of 90% Cu 10% Ni significantly lowered the microbial burden, primarily "Staphylococci", on arm surfaces of phlebotomy chairs versus wooden arm surfaces. The median reduction for total bacteria on the copper alloy chairs arms was 90%. Use of the chair with copper arm tops resulted in a 17-fold lower risk of exposure to environmental microbes than when patients used the standard chair. The majority of the samples from the chairs with copper components were below the 500 CFU/cm level believed to represent a risk to hospital patients. The microbiocidal properties of the