Organ procurement of kidneys is a relatively widespread practice. For the heart normothermic preservation has been used in which the heart is provided with warm oxygenated blood and so continues to beat ex-vivo during its preservation. This technique has also been applied to lungs and led to the emergence of donor lung reconditioning centres in North America. For the liver, hypothermic and normothermic techniques are being used with evidence to suggest that both may be beneficial . The HOPE (HIV Organ Policy Equity) Act allows for clinical research on organ transplantation from HIV+ donors to HIV+ recipients. The Act was passed by
Water organ Alexandria (c. 62 AD). Like the water clocks (clepsydra) of Plato's time, they were not regarded as playthings but might have had a particular significance in Greek philosophy, which made use of models and simulacra of this type. Hydraulically blown organ pipes were used to imitate birdsong, and musicologists Susi Jeans and Arthur W.J.G. Ord-Hume have suggested that it was used to create the sounds of the Vocal Memnon. For the latter, solar heat was used to syphon water from one closed tank into another, thereby producing compressed air for sounding the pipes. Characteristics of the hydraulis have been inferred