Chemical element same atomic number, or number of protons. Nuclear scientists, however, define a pure element as one that consists of only one stable isotope. For example, a copper wire is 99.99% chemically pure if 99.99% of its atoms are copper, with 29 protons each. However it is not isotopically pure since ordinary copper consists of two stable isotopes, 69% Cu and 31% Cu, with different numbers of neutrons. However, a pure gold ingot would be both chemically and isotopically pure, since ordinary gold consists only of one isotope, Au. Atoms of chemically pure elements may bond to each other chemically in
CU-2010 and CU-2020 a substrate, due to its peptide-like properties. After intravenous infusion, CU-2010 is quickly cleared as it has a half-life of about 20 minutes (in rats and dogs). Polymerization and covalent attachment of polymer chains of polyethylene glycol (PEG) or pegylation results in the formation of CU-2020, which has a longer half-life of 45 minutes. The advantage of the short half-life of CU-2010 is that it allows it to work in an “on-off” mode, hence being able to adapt to the haemostatic situation of the moment. CU-2010 and CU-2020 have the ability to inhibit plasmin to a similar extent as aprotinin,