Chemical Signaling Simulates Exercise in Cartilage Cells (image) Duke University Medical Center Share Print E-Mail Caption In these cartilage cells, fluorescent dyes measure changes in the concentration of calcium in response to mechanical loading. Green indicates areas of high calcium, while red indicates areas of low calcium within each cell. Credit Duke Medicine Usage Restrictions None 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.