Production of zirconium-88 via proton irradiation of metallic yttrium and preparation of target for neutron transmission measurements at DICER.

A process for the production of tens to hundreds of GBq amounts of zirconium-88 (88Zr) using proton beams on yttrium was developed. For this purpose, yttrium metal targets (≈20 g) were irradiated in a ~16 to 34 MeV proton beam at a beam current of 100-200 µA at the Los Alamos Isotope Production Facility (IPF). The 88Zr radionuclide was produced and separated from the yttrium targets using hydroxamate resin with an elution yield of 94(5)% (1σ). Liquid DCl solution in D2O was selected as a suitable 88Zr sample matrix due to the high neutron transmission of deuterium compared to hydrogen and an even distribution of 88Zr in the sample matrix. The separated 88Zr was dissolved in DCl and 8 µL of the obtained solution was transferred to a tungsten sample can with a 1.2 mm diameter hole using a syringe and automated filling station inside a hot cell. Neutron transmission of the obtained 88Zr sample was measured at the Device for Indirect Capture Experiments on Radionuclides (DICER).

Design and Evaluation of a Percutaneous Fragment Manipulation Device for Minimally Invasive Fracture Surgery.

Reduction of fractures in the minimally invasive (MI) manner can avoid risks associated with open fracture surgery. The MI approach requires specialized tools called percutaneous fragment manipulation devices (PFMD) to enable surgeons to safely grasp and manipulate fragments. PFMDs developed for long-bone manipulation are not suitable for intra-articular fractures where small bone fragments are involved. With this study, we offer a solution to potentially move the current fracture management practice closer to the use of a MI approach. We investigate the design and testing of a new PFMD design for manual as well as robot-assisted manipulation of small bone fragments. This new PFMD design is simulated using FEA in three loading scenarios (force/torque: 0 N/2.6 Nm, 75.7 N/3.5 N, 147 N/6.8 Nm) assessing structural properties, breaking points, and maximum bending deformations. The PFMD is tested in a laboratory setting on Sawbones models (0 N/2.6 Nm), and on ex-vivo swine samples (F = 80 N ± 8 N, F = 150 ± 15 N). A commercial optical tracking system was used for measuring PFMD deformations under external loading and the results were verified with an electromagnetic tracking system. The average error difference between the tracking systems was 0.5 mm, being within their accuracy limits. Final results from reduction maneuvers performed both manually and with the robot assistance are obtained from 7 human cadavers with reduction forces in the range of (F = 80 N ± 8 N, F = 150 ± 15 N, respectively). The results show that structurally, the system performs as predicted by the simulation results. The PFMD did not break during ex-vivo and cadaveric trials. Simulation, laboratory, and cadaveric tests produced similar results regarding the PFMD bending. Specifically, for forces applied perpendicularly to the axis of the PFMD of 80 N ± 8 N deformations of 2.8, 2.97, and 3.06 mm are measured on the PFMD, while forces of 150 ± 15 N produced deformations of 5.8, 4.44, and 5.19 mm. This study has demonstrated that the proposed PFMD undergoes predictable deformations under typical bone manipulation loads. Testing of the device on human cadavers proved that these deformations do not affect the anatomic reduction quality. The PFMD is, therefore, suitable to reliably achieve and maintain fracture reductions, and to, consequently, allow external fracture fixation.

The Fundamental Neutron Physics Beamline at the Spallation Neutron Source.

The Spallation Neutron Source (SNS), currently under construction at Oak Ridge National Laboratory with an anticipated start-up in early 2006, will provide the most intense pulsed beams of cold neutrons in the world. At a projected power of 1.4 MW, the time averaged fluxes and fluences of the SNS will approach those of high flux reactors. One of the flight paths on the cold, coupled moderator will be devoted to fundamental neutron physics. The fundamental neutron physics beamline is anticipated to include two beam-lines; a broad band cold beam, and a monochromatic beam of 0.89 nm neutrons for ultracold neutron (UCN) experiments. The fundamental neutron physics beamline will be operated as a user facility with experiment selection based on a peer reviewed proposal process. An initial program of five experiments in neutron decay, hadronic weak interaction and time reversal symmetry violation have been proposed.

Can medical students afford to choose primary care? An economic analysis of physician education debt repayment.

PURPOSE: Some discussions of physician specialty choice imply that indebted medical students avoid choosing primary care because education debt repayment seems economically unfeasible. The authors analyzed whether a physician earning a typical primary care salary can repay the current median level of education debt and meet standard household expenses without incurring additional debt. METHOD: In 2010-2011, the authors used comprehensive financial planning software to model the annual finances for a fictional physician's household to compare the impact of various debt levels, repayment plans, and living expenses across three specialties. To accurately develop this spending model, they used published data from federal and local agencies, real estate sources, and national organizations. RESULTS: Despite growing debt levels, the authors found that physicians in all specialties can repay the current level of education debt without incurring more debt. However, some scenarios, typically those with higher borrowing levels, required trade-offs and compromises. For example, extended repayment plans require large increases in the total amount of interest repaid and the number of repayment years required, and the use of a federal loan forgiveness/repayment program requires a service obligation such as working at a nonprofit or practicing in a medically underserved area. CONCLUSIONS: A primary care career remains financially viable for medical school graduates with median levels of education debt. Graduates pursuing primary care with higher debt levels need to consider additional strategies to support repayment such as extended repayment terms, use of a federal loan forgiveness/repayment program, or not living in the highest-cost areas.