41.   Meanwhile, the Sojourner rover is continuing to roam around the landscape, measuring the chemical composition of rocks and soil.

42.   Observations with it are expected to reveal the chemical composition of celestial objects and show how their composition changed as the universe evolved.

43.   Others have altered the chemical composition of the paper.

44.   Recently, Clark led a team that completed the design of a device that uses cold neutrons to help researchers learn the chemical composition of materials.

45.   Scientists have developed a new technique to analyze the chemical composition of ancient rocks for hints about what the air was like billions of years ago.

46.   She said the Siemens machine would be able to analyze the flow of blood in vessels, or track functional data and chemical composition in the brain.

47.   So one good guide to judging longevity is the chemical composition of a cell.

48.   Some are based on the use of thicker paper, others on altered chemical composition of the paper.

49.   Studies are also needed to determine how powder characteristics like particle size and chemical composition relate to the risk of becoming ill.

50.   Study of the chemical composition of these shapes, which is just beginning, could provide clear evidence of their biological nature, McKay said.