Three technologies developed by Livermore researchers and their collaborators have been named winners in the 2016 R&D 100 awards. The awards, sponsored by the trade journal R&D Magazine, are given annually for the top 100 industrial inventions worldwide. This year’s award winners are as follows:
Fracture healing involves communication between bone, muscle, vasculature, and the thin membrane (periosteum) covering the outer surface of bones. The periosteum contains stem cells that migrate to the fracture site and differentiate into chondrocytes (cartilage-forming cells) or osteoblasts (bone-forming cells). Until now, little was known about the interaction between the periosteum stem cells and the bone cells during fracture healing, but a team of scientists from Lawrence Livermore, the University of California at Merced and Davis, Indiana University, and Regeneron Pharmaceuticals has identified the Sostdc1 gene as a regulator of periosteum stem cell activity during fracture repair. The research appears in the April 19, 2016, edition of the journal Bone. The study suggests that Sostdc1 plays an important role in stem cell self-renewal and differentiation, which may be useful for developing novel therapeutics for difficult-to-heal fractures. Mice lacking the gene, despite having a lower density of trabecular bone, had thicker, denser cortical bone, which healed at an accelerated rate relative to their genetically normal counterparts. The team also showed that suppression of Sostdc1 induces a population of stem cells to rapidly expand and invade the fracture and help repair it.
“Future studies may allow us to harness the behavior of these stem cells in other parts of the body where they may do even more good,” says Nicole Collette, a Livermore biologist and lead author of the study. “This regulator is expressed all over the body, including in other tissues where stem cells are found.”
Contact: Nicole Collette (925) 423-2353 (collette2@llnl.gov).
A team of scientists has found that the dehydration of chlorite is likely crucial in explaining the anomalously high electrical conductivity (EC) observed in Earth’s mantle. The high EC, observed in mantle wedge regions at depths of 40 to 100 kilometers, had often been attributed to the aqueous fluid released from descending slabs, but until now laboratory-based measurements of EC were significantly lower and could not readily explain the geophysically observed high EC.
The new research, appearing in the May 6, 2016, edition of Science Advances, shows that the EC of chlorite is similar to that of other hydrous silicate minerals. “We have measured the EC of a natural chlorite at pressures and temperatures relevant for the subduction zone setting,” says former Livermore geophysicist Davide Novella. “In our experiment, we observed two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in EC can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of EC.”
The team found that the further increase in EC is also related to the growth of an interconnected network of highly conductive and chemically impure magnetite mineral phases, in addition to chlorite dehydration. Novella explains, “Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and also could be responsible for the fixed depth of melting at the top of the subducting slab.”
Contact: Anne Stark (925) 422-9799 (stark8@llnl.gov).