Biological Rhythms in Human Cells (image) University of Veterinary Medicine -- Vienna Share Print E-Mail Caption Fatty acid composition in human cell membranes changes throughout the day. Credit Photo: Susanne Schwaiger Usage Restrictions The photo may only be used in the context of this press release. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.