Bone cell loss for astronauts used to be as high as 1 to 2 percent per month -- not all of which is recoverable. Recent developments in material and process engineering has reduced that amount to 0.3 percent per month.

Bone loss and biological fluid flow in space were the main topics of a talk sponsored by the University chapter of the Society for the Advancement of Material and Process Engineering.

University Assistant Professor of Chemical Engineering John Frangos discussed "Fluid Flow and Bone Loss in Space" at a monthly meeting of SAMPE, held in 232 Hammond last night.

"Osteoporosis in space is far worse, far sooner than any human osteoporosis on earth," Frangos said.

Osteoporosis results when bone-absorbing cells are more active than bone-producing cells and bones become much more porous and brittle, Frangos said.

Exercise decreases bone loss in space, Frangos said, adding that osteoblasts (bone forming cells) inexplicably become nonfunctional in the lowered gravity exerted on astronauts orbiting earth. This bone loss may be permanent in some cases, causing health problems when astronauts return to earth, he said.

Frangos is currently involved in experiments to determine how shear stress -- the flow pressure exerted on bone cells by fluid moving through the bone or against blood vessels -- affects bone production. Shear stress is difficult to measure accurately, he said.

"Living cells can all sense fluid shear," Frangos said. "I think it's a general effect."

Shear stress also causes blood vessel walls to secrete hormones which cause the vessel wall to dilate or constrict, controlling blood flow, Frangos said.

Understanding how the cells on the vessel walls react to shear stress can lead to advancement in blood disease research, such as atheroschlerosis, Frangos said, adding that smoking may inhibit blood vessels' sensitivity to shear stress.

Frangos received his Bachelor of Engineering Science degree at Johns Hopkins University in 1981; he received his masters of science degree at Stanford a year later. He received his Ph.D. at Rice University in Houston in 1986.

SAMPE has 340 international chapters, with professional and student material and process engineering members, Chapter President Scott White said. The University chapter was begun last September and has 35 members, he said.

The group hosts speakers every month to garner interest in process and material engineering and to bridge the gap between engineers and the general public, White said.

The group is currently sponsoring a SAMPE Research Day, on April 16, which will provide engineers from the Penn State and other universities to present their papers and display current projects, White said.