they stopped using silver in half dollars in 1859.
when did they stop using silver in half dollars?
1859
by the early 1960s, the rising price of silver neared the point where the bullion value of u.s. silver coins would exceed face value. in 1965, the u.s. introduced layered-composition coins made of a pure copper core sandwiched between two cupronickel outer faces. the silver content of dimes and quarters was eliminated, but the kennedy half-dollar composition contained silver (reduced from 90% to 40%) from 1965 to 1970. even with its reduced silver content, the half dollar attracted widespread interest from speculators and collectors, and that interest led to widespread hoarding of half dollars dated 1970 and earlier. in 1971, the half's composition was changed to match that of the clad dimes and quarters, and with an increase in production, the coin saw a modest increase in usage; by this time however, many businesses and the public had began to lose interest in the coin and it gradually became scarce in circulation later in the 1970s. merchants stopped ordering half dollars from their banks, and many banks stopped ordering half dollars from the federal reserve, and the u.s. mints sharply reduced production of the coins.
half dollar (united states coin)
a 2014 systemic review concluded that using silver alloy‐coated catheters showed no significant difference in incidences of symptomatic catheter-associated urinary tract infections (cauti) versus using standard catheters, although silver-alloy catheters seemed to cause less discomfort to patients. these catheters are associated with greater cost than other catheters. a 2014 multicenter cohort study found that using a silver-alloy hydrogel urinary catheter did reduce symptomatic catheter-associated urinary tract infection (cauti) occurrences as defined by both nhsn and clinical criteria. a 2011 critical analysis of eight studies found a consistent pattern which supported using silver-alloy urinary catheters over uncoated catheters to reduce infections in adult patients, and concluded that using silver-alloy catheters would significantly improve patient care. a 2007 systemic review concluded that using silver-alloy indwelling catheters for short-term catheterizing will reduce the risk of catheter acquired urinary tract infection, but called for further studies to evaluate the economic benefits of using the expensive silver alloy-catheters. two systemic reviews in 2004 found that using silver-alloy catheters reduced asymptomatic and symptomatic bacteriuria more than standard catheters, for patients who were catheterised for a short time. a 2000 randomized crossover study found that using the more expensive silver-coated catheter may result in cost savings by preventing nosocomial uti infections, and another 2000 study found that using silver alloy catheters for short-term urinary catheterization reduces the incidence of symptomatic uti and bacteremia compared with standard catheters, and may thus yield cost savings.
medical uses of silver