The Oklo phenomenon

Until recently, scientists believed that the chemical elements were synthesized only in stars. The discovery of the Oklo phenomenon in the Republic of Gabon in 1972 has revealed, however, that a nuclear “fire” had existed on the earth and largescale transmutations of the elements were occurring on our planet 1.7·10⁹ years ago. The formation of natural (or Pre-Fermi) reactors is closely related to the appearance of life on our planet earth. The Pre-Fermi reactors were probably never formed until about 2·10⁹ years ago, when oxygen was injected into the earth's atmosphere by a new generation of living organisms carrying out photosynthesis.     

Fetal death secondary to needle laceration during 2nd trimester aminiocentesis: A case report

A case of fetal death secondary to a needle laceration during a second trimester amniocentesis is presented. The need for careful pathologic evaluation of fetuses lost subsequent to these procedures is stressed.     

Optical fibers for transmission of information

This article is meant to provide an overview on light and information transmission through glass fibers, the most important methods of fiber fabrication, and some examples of present-day applications.     

Verhinderung einer Polymervernetzung durch Rühren

The Science of Nature -