Artificial heart valve was later changed to use silicone-coated material. The first implantation of mechanical heart valve to human was performed by Dr. Hufnagel on 11 September 1952, using the valve that he developed. This event accelerated the development of other artificial heart valves. Artificial heart valve An artificial heart valve is a device implanted in the heart of a patient with valvular heart disease. When one of the four heart valves malfunctions, the medical choice may be to replace the natural valve with an artificial valve. This requires open-heart surgery. Valves are integral to the normal physiological functioning of the human heart.
Human artificial chromosome Human artificial chromosome A human artificial chromosome (HAC) is a microchromosome that can act as a new chromosome in a population of human cells. That is, instead of 46 chromosomes, the cell could have 47 with the 47th being very small, roughly 6–10megabases (Mb) in size instead of 50–250Mb for natural chromosomes, and able to carry new genes introduced by human researchers. Ideally, researchers could integrate different genes that perform a variety of functions, including disease defense. Alternative methods of creating transgenes, such as utilizing yeast artificial chromosomes and bacterial artificial chromosomes, lead to unpredictable problems. The genetic material introduced