Ionizing radiation isnt generally thought of as good for you, but its good for artificial hips. A new reference material from the National Institute of Standards and Technology (NIST) will help researchers determine what methods of irradiating the plastic parts in joint replacements during manufacturing will best increase their wear resistance.
Reference Material 8457 is intended to help address concerns about the long-term durability of orthopedic hip implants amid growing use of these devices in younger, more active patients. It is well known that radiation can create new chemical bonds between adjacent molecular chains in a special form of polyethylene used to make the socket for the metal ball and shaft in an artificial hip. This "crosslinking" creates a structure that resists sliding forces and wear. Manufacturers and researchers need to control radiation conditions to achieve the intended wear resistance; too much radiation causes brittleness, and too little can result in poor wear resistance.
The NIST material consists of 10 small, identical cubes of polyethylene. The cubes are intended for use as control samples in a new ASTM International standard test method. The method involves immersing cubes in an organic liquid and measuring how much the material swells. Samples that expand the most have the least amount of crosslinking. Each reference material comes with a certificate that provides precise cube dimensions and information about swelling from a series of round-robin tests involving six laboratories.
Laura Ost | EurekAlert!
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Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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24.03.2017 | Physics and Astronomy