Bone versus implant: an atypical presentation of a typical complication of forearm fractures

Both bone forearm fractures are one of the most common upper limb fractures operated by orthopedicians. Although the primary surgery is usually relatively straight forward and simple, but we present a case where the primary surgery failed and the patient presented with a deformed hand after 5 months, even though there were signs of union on radiographs. When operated upon, although the ulna had undergone primary bone healing and a peri-implant fracture had occurred, whereas radius had refractured from the fracture site and the plate was bent giving the deformed appearance. We discuss this unique complication, the planning, difficulties and scope of errors in such a situation, where the race to union is won by ulna but lost by radius

Feasibility study for non-intrusive ablation of prostate by electromagnetic radiation

We have developed and successfully tested models and numerical schemes for clean ablation of well-defined regions inside materials without causing damage to the surface and surrounding material, using lasers. The key to our approach is the ability is to control the beam intensity along its axis. A high intensity radiation is delivered to the beam focal area, while the intensity is kept below damage threshold along the beam. The purpose of this study was to investigate if this program can be extended to microwave electromagnetic heating of selected regions inside the dielectrics. If successful, the new technique can be used to ablate prostate cancer non-intrusively as the treatment will not require bringing the EM radiation source close to the cancerous tissue. In this study, the focal length of the lens and the beam diameter at the lens are calculated such that it can deliver high intensity electromagnetic radiation of a prescribed frequency to a given region inside the human body. However, the calculated parameters are inconvenient for an experimental implementation of the results. As the frequency is increased, experimental implementation of the technique becomes feasible, but a high frequency dose of radiation to the body results in increased damaage. Thus, the present technique and results can be used to inscribe features inside the usual dielectrics with high frequency radiation, but achieving a suimilar goal with low frequency radiation will require an alternative technique or further innovation.NRC publication: Ye

Comment on, "Breakdown of the Hellmann-Feynman theorem: degeneracy is the key"

It is clarified that the conclusions reached in Phys. Rev. B 66 033110 (2002) result from erroneous application of the Hellmann-Feynman theorem, and a result deduced there for two-fold degenerate eigenvalues is generalized.Peer reviewed: YesNRC publication: Ye

Numerical scheme to determine the photonic properties of tunable crystals

The dielectric distribution and polarizability of certain materials, e.g., the liquid dielectrics, change in response to the external electromagnetic field. Since their photonic properties can be adjusted by controlling the applied field, these materials can be used to construct tunable photonic band gap crystals. Due to recent advances in tunable photonic bandgap materials technology, it has become necessary to determine the properties of the propagating fields accurately. Numerical methods currently in use are quite cumbersome and place limits on the accuracy of the solutions. A numerical scheme is developed here by expressing the solution in the framework of the Feynman path integral formulation of quantum mechanics. The formulation describes the evolution of the solution in terms of a propagator, which can be determined by the method of fast Fourier transforms. The resulting numerical scheme is more efficient and reliable than other similar methods.Peer reviewed: YesNRC publication: Ye