New fossils of embryonic ichthyosaurs are both the geologically youngest and the physically smallest known ichthyosaur embryos. The embryos are articulated, though only partially preserved, and are located within the body cavity of an adult, presumably the mother. The embryos and adult were found in association with several other individuals of differing size classes, all of which appear to be ...

Exceptionally preserved sauropod eggshells discovered in Upper Cretaceous (Campanian) deposits in Patagonia, Argentina, contain skeletal remains and soft tissues of embryonic Titanosaurid dinosaurs. To preserve these labile embryonic remains, the rate of mineral precipitation must have superseded post-mortem degradative processes, resulting in virtually instantaneous mineralization of soft tiss...

Ostracod crustaceans are the most abundant fossil arthropods and are characterized by a long stratigraphic range. However, their soft parts are very rarely preserved, and the presence of ostracods in rocks older than the Silurian period [1-5] was hitherto based on the occurrence of their supposed shells. Pyritized ostracods that preserve limbs and in situ embryos, including an egg within an ova...

Prof. Xiao’s current research focuses on the biological evolution and environmental changes in the Proterozoic Eon (2500 to 543 million years ago). He has been working on some of the most important and exquisitely preserved microfossils from the ca. 600-million-year-old Doushantuo Formation in South China. These microfossils include multicellular red algae and animal embryos at successive cleav...

Three-dimensional analyses of the early Ediacaran microfossils from the Weng'an biota (Doushantuo Formation) have focused predominantly on multicellular forms that have been interpreted as embryos, and yet they have defied phylogenetic interpretation principally because of absence of evidence from other stages in their life cycle. It is therefore unfortunate that the affinities of the various o...

The Early Cambrian organism Olivooides is known from both embryonic and post-embryonic stages and, consequently, it has the potential to yield vital insights into developmental evolution at the time that animal body plans were established. However, this potential can only be realized if the phylogenetic relationships of Olivooides can be constrained. The affinities of Olivooides have proved con...

Abstract Premature ovarian insufficiency (POI) is characterized by symptoms caused dysfunction in patients aged <40 years. It associated with a shortened reproductive lifespan. The only effective treatment for who are eager to become pregnant IVF/Embryo Transfer (ET) using oocytes donated young women. However, the use of technique constrained limited supply and ethical issues. Some POI s...

the use of donated embryos has offered hope for infertile couples who have no other means to have children. in iran, fertility centers use fertile couples as embryo donors. in this paper, the advantages and disadvantages of this procedure will be discussed. we conclude that embryo-donation should be performed with frozen embryos thus preventing healthy donors from being harmed by fertility drug...

Subfertility is a major health issue worldwide, and one that is growing because of an increasing number of subfertile couples, various causes of decreased fertility, and poorly understood mechanisms. In The Lancet, three Series papers on fertility preservation discuss the eff ects of physiological and pathological factors on human fertility, and collectively show that fertility preservation is ...

background: the risk of multiple pregnancies often present in programs of in vitro fertilization (ivf) is an important force for embryo cryopreservation. on the other hand ethical restriction and assurance of potential fertility following chemo/radio therapy has led scientists to focus on female gamete preservation. objective: optimizing vitrification protocol by using less concentrated cryopro...