Beam Energy Considerations for Gold Nano-Particle Enhanced Radiation Treatment

Purpose: A novel approach using nano technology enhanced radiation modalities is investigated. The proposed methodology uses antibodies labeled with organically inert metals with a high atomic number. Irradiation using photons with energies in the kilo--electron volt (keV) range show an increase in dose due to a combination of an increase in photo-electric interactions and a pronounced generation of Auger and/or Coster-Kronig (A-CK) electrons. Methods: The dependency of the dose deposition on various factors is investigated using Monte Carlo simulation models. The factors investigated include: agent concentration, spectral dependency looking at mono--energetic sources as well as classical bremsstrahlung sources. The optimization of the energy spectrum is performed in terms of physical dose enhancement as well as the dose deposited by Auger and/or Coster-Kronig electrons and their biological effectiveness. Results: A quasi-linear dependency on concentration and an exponential decrease within the target medium is observed. The maximal dose enhancement is dependent on the position of the target in the beam. Apart from irradiation with low photon energies (10 - 20 keV) there is no added benefit from the increase in generation of Auger electrons. Interestingly, a regular 110kVp bremsstrahlung spectrum shows a comparable enhancement in comparison with the optimized mono--energetic sources. Conclusions: In conclusion we find that the use of nano-particle enhanced shows promise to be implemented quite easily in regular clinic on a physical level due to the advantageous properties in classical beams.Comment: Preprint submitted to Phys Med Bio

Growth of Single Unit-Cell Superconducting La2−x_{2-x}Srx_xCuO4_{4} Films

We have developed an approach to grow high quality ultrathin films of La$_{2-x}$Sr$_x$CuO$_{4}$ with molecular beam epitaxy, by adding a homoepitaxial buffer layer in order to minimize the degradation of the film structure at the interface. The advantage of this method is to enable a further reduction of the minimal thickness of a superconducting La$_{1.9}$Sr$_{0.1}$CuO$_{4}$ film. The main result of our work is that a single unit cell (only two copper oxide planes) grown on a SrLaAlO$_4$ substrate exhibits a superconducting transition at 12.5 K (zero resistance) and an in-plane magnetic penetration depth $\lambda_{ab}(0)$ = 535 nm.Comment: to be published in "Solid State Electonics" special issue, conference proceedings of the 9th Workshop on Oxide Electronics, St-Pete Beach, FL, 20-23 november 2002 : 12 pages 4 figures in preprint versio

Domain growth of Dy2O3 buffer layers on SrTiO3

Dy2O3 layers have been grown on SrTiO3 by molecular beam epitaxy. X-ray and electron diffraction patterns clearly show that Dy2O3 grows epitaxially on SrTiO3 with {100} planes parallel to the substrate surface. Transmission electron microscopy reveals that the Dy2O3 film breaks up into small domains (10-40 nm). This leads to the formation of terraces which limits the structural perfection of thin overgrown DyBa2Cu3O7 by introducing steps and small misorientations (within 3°). The resulting surface corrugation does not preclude the growth of epitaxial c-axis DyBa2Cu3O7 films with a Tc0 of 86 K. Crystallographic analysis and image calculations show that the domain growth of Dy2O3 is associated with the formation of 90° rotation twin

Feline arterial thromboembolism : prognostic factors and treatment

Feline arterial thromboembolism (ATE) is a complete or partial obstruction of a peripheral artery caused by a thrombus that was formed at a distant site. The most common underlying cause in cats is cardiomyopathy. Given the clinical presentation, often without preceding signs, an ATE event is considered one of the most distressing emergency conditions in feline practice. Often, these cats are euthanized at the time of diagnosis. However, recent scientific research has shown that a subpopulation of these patients may have long-term survival. In case of adequate treatment and follow-up, some cats survive over a year with a satisfying quality of life. Key points of ATE are the identification of specific prognostic factors in the individual patient in order to guide owner communication, the decision to treat or not to treat, individually adjusted patient management and regular monitoring, which are discussed in this article

Anticipating the dynamics of chaotic maps

We study the regime of anticipated synchronization in unidirectionally coupled chaotic maps such that the slave map has its own output reinjected after a certain delay. For a class of simple maps, we give analytic conditions for the stability of the synchronized solution, and present results of numerical simulations of coupled 1D Bernoulli-like maps and 2D Baker maps, that agree well with the analytic predictions.Comment: Uses the elsart.cls (v2000) style (included). 9 pages, including 4 figures. New version contains minor modifications to text and figure