The National Science Foundation is profiling cardiac stent research being done by collaborators from University of Houston and University of Zagreb in Croatia. They’re using mathematical computer models to optimize for different characteristics that stents exhibit, helping to design new stents and help simulate ones that are on the drawing board.
Together with her collaborator, Josip Tambaca of the University of Zagreb in Croatia, and her doctoral student, Mate Kosor, Canic wrote a much simpler program that approximates stents as meshes of one-dimensional rods. This program let the researchers achieve the same result using just 400 nodes.
Using their simplified model, the researchers have examined the designs of several stents on the market to see which structures seem to be best for specific blood vessels or procedures. For instance, they found that stents with an “open design”–where every other horizontal rod is taken out–bend easily, which makes them good to put in curvy coronary arteries.
Canic and Tambaca have also used the model to design a stent with mechanical properties specifically tailored to an experimental heart-valve replacement procedure. She found that this specialized stent works best for the procedure when it’s stiff in the middle and less stiff at the ends. In addition, she has found that combining “bendiness” with radial stiffness–where you can bend the stent into a U shape, but you can’t squeeze the tube shut–produces a stent with less chance of buckling than those that are currently in use.
Today, Canic is helping a team at the Texas Heart Institute study an unusual source for stent coating: ear cartilage. The team believes this easy-to-harvest tissue will make stents more biocompatible, though they don’t yet know how ear cartilage cells grow or behave in environments like human blood vessels.
Canic is using her computer programs, developed together with Tsorng-Whay Pan, Roland Glowinski and students, to simulate how blood interacts with the stent-coating cartilage cells and how the cells stick (or don’t) to the stent surface. She plugs in different fluid thicknesses and shear forces of blood flowing over the stent to see what might encourage the cartilage on freshly coated stents to stabilize quickly. The models have helped her collaborators learn the best conditions to test in follow-up experiments as they search for ways to pre-treat stents before doctors implant them.
Full story: Scientists Use Math to Build Better Stents…
To kick off the new school year Epocrates is giving all U.S. medical students a free copy of its popular Epocrates Essentials suite which typically costs $159.
Another discerning feature of the m90z is that it can be opened like a more traditional desktop box via two blue push tabs, and changing common components doesn’t require any tools. This feature should allow lower cost maintenance and the ability to upgrade components, such as swapping the standard hard drive for a faster solid state model, adding on RAM, or upgrading to a Blue-Ray disk drive. The system uses laptop sized RAM chips but a full size hard drive. Cursory review found easy access to all standard internal components.
Many drugs that would benefit from transdermal delivery are either made of molecules too large to penetrate the skin or are hydrophilic and so don’t absorb very well. To overcome these limitations, Purdue University scientists have created a pump to literally push drugs through microneedles of 20 micron diameter. The pump requires no batteries and is activated by pushing your finger against it for about twenty seconds.
Exmovere out of McLean, Virginia claims to have developed baby clothing that can monitor heart rate, “emotional state”, and level of activity, and relay that information wirelessly to a computer or cell phone. Paranoid parents will be able to keep a virtual eye on their kids 24/7, and maybe worries about SIDS and infant sleep apnea can be diminished. An initial production of 1,000 units will be made available in 2011 to select customers.
