The embryos were then transferred to recipient women. They had pregnancies when the recipient's cycle was from 4 days in front of to 3 days behind the donor's uterus at ovulation. This suggests a window of implantation of up to 7 days. Navot et al, in 1991 reported on donor embryo transfers done with 2-3 day old embryos on recipient cycle days 15-20 (artificial cycles controlled with meds). Pregnancies resulted from transfers on all days. This suggests a window of at least 6 days.
Polymers. The word polymer literally means many parts.. A polymeric solid material may be considered to be one that contains many chemically bonded parts or units which themselves are bonded together to form a solid.Two industrially important polymeric materials are plastics and elastomers.he word polymer literally means many parts.. A polymeric solid material may be considered to be one that contains many chemically bonded parts or units which themselves are bonded together to form a solid.
POLYMERS. Polymers are substances whose molecules have high molar masses and are composed of a large number of repeating units. There are both naturally occurring and synthetic polymers. Among naturally occurring polymers are proteins, starches, cellulose, and latex.Synthetic polymers are produced commercially on a very large scale and have a wide range of properties and uses. The materials commonly called plastics are all synthetic polymers.Polymers are formed by chemical reactions in which a large number of molecules called monomers are joined sequentially, forming a chain. In many polymers, only one monomer is used. In others, two or three different monomers may be combined.he materials commonly called plastics are all synthetic polymers. Polymers are formed by chemical reactions in which a large number of molecules called monomers are joined sequentially, forming a chain. In many polymers, only one monomer is used.