Negotiating tensions in identity: from physical education teacher educator to academic leader

Academics in Physical Education Teacher Education (PETE), similar to their counterparts in other disciplines, receive little formal preparation when they take on academic leadership positions. Yet such career changes require different skill sets and expose academics to complex challenges of leadership. We (three academics) initiated this study to explore the implications of academic leadership positions for our PETE identities. We wished to unpack the consequences of taking on these leadership roles, or our ‘desire to become more’ and ‘to better understand’ (Ovens, A., & Fletcher, T. (2014). Doing self-study: The art of turning inquiry on yourself. In A. Ovens & T. Fletcher (Eds.), Self-study in physical education teacher education: Exploring the interplay of practice and scholarship (Vol. 13, pp. 3–14). London: Springer, p. 7). This research used a collective self-study methodology and drew on Skype meetings, reflections, critical friend prompts and emails. We present our findings as coming to view identity changes as tensions: bridging between roles; competing identities; identity as stable or malleable; and educator or fiscal manager. Gee’s four identity perspectives including natural, institutional, discursive and affinity are used to unpack these tensions. While challenges associated with our role change persist, collective SSTEP was critical to understanding ourselves, the tensions experienced, and navigating the gaps between PETE and academic leadership

Polarized 129Xe129Xe optical pumping/spin exchange and delivery system for magnetic resonance spectroscopy and imaging studies

We describe the design and construction of a laser-polarized 129Xe129Xe production and delivery system that is used in our in vitro and in vivo magnetic resonance imaging (MRI) experiments. The entire apparatus including lasers and optics, rapidly actuated valves, heating and cooling, and transport tubing lies in the high magnetic field environment of a 2 T MRI magnet. With approximately 7.5% 129Xe129Xe polarization, 157 cc atm of xenon gas is produced and stored as xenon ice every 5 min. Large quantities of polarized 129Xe129Xe can be obtained by cycling this process. The xenon is subsequently delivered in a controlled fashion to a sample or subject. With this device we have established the feasibility of using laser-polarized 129Xe129Xe as a magnetic tracer in MRI. This reliable, effective, and relatively simple production method for large volumes of 129Xe129Xe can be applied to other areas of research involving the use of laser-polarized noble gases. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69879/2/RSINAK-70-2-1546-1.pd

Incorporating metapopulation Dynamics to Inform Invasive Species Management: Evaluating Bighead and Silver Carp Control Strategies in the Illinois River

1. Invasive species management can benefit from predictive models that incorporate spatially explicit demographics and dispersal to guide resource allocation decisions. 2. We used invasive bigheaded carps (Hypophthalmichthys spp.) in the Illinois River, USA as a case study to create a spatially explicit model to evaluate the allocation of future management efforts. Specifically, we compared additional harvest (e.g. near the invasion front vs. source populations) and enhanced movement deterrents to meet the management goal of reducing abundance at the invasion front. 3. We found additional harvest in lower river pools (i.e. targeting source populations) more effectively limited population sizes upriver at the invasion front compared to allocating the same harvest levels near the invasion front. Likewise, decreasing passage (i.e. lock and dam structures) at the farthest, feasible downriver location limited invasion front population size more than placing movement deterrents farther upriver. 4. Synthesis and applications. Our work highlights the benefits of adopting a multipronged approach for invasive species management, combining suppression of source populations with disrupting movement between source and sink populations thereby producing compounding benefits for control. Our results also demonstrate the importance of considering metapopulation dynamics for invasive species control programs when achieving long-term management goals

Magnetic Resonance Imaging with laser polarized 129Xe129Xe

Magnetic Resonance Imaging with laser-polarized 129Xe129Xe can be utilized to trace blood flow and perfusion in tissue for a variety of biomedical applications. Polarized xenon gas introduced in to the lungs dissolves in the blood and is transported to organs such as the brain where it accumulates in the tissue. Spectroscopic studies combined with imaging have been used to produce brain images of 129Xe129Xe in the rat head. This work establishes that nuclear polarization produced in the gas phases survives transport to the brain where it may be imaged. Increases in polarization and delivered volume of 129Xe129Xe will allow clinical measurements of regional blood flow. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87439/2/200_1.pd

Biological consequences of nanoscale energy deposition near irradiated heavy atom nanoparticles

Gold nanoparticles (GNPs) are being proposed as contrast agents to enhance X-ray imaging and radiotherapy, seeking to take advantage of the increased X-ray absorption of gold compared to soft tissue. However, there is a great discrepancy between physically predicted increases in X-ray energy deposition and experimentally observed increases in cell killing. In this work, we present the first calculations which take into account the structure of energy deposition in the nanoscale vicinity of GNPs and relate this to biological outcomes, and show for the first time good agreement with experimentally observed cell killing by the combination of X-rays and GNPs. These results are not only relevant to radiotherapy, but also have implications for applications of heavy atom nanoparticles in biological settings or where human exposure is possible because the localised energy deposition high-lighted by these results may cause complex DNA damage, leading to mutation and carcinogenesis.</p

Distribution and dynamics of laser-polarized 129 Xe magnetization in vivo

The first magnetic resonance imaging studies of laser-polarized 129 Xe, dissolved in the blood and tissue of the lungs and the heart of Sprague-Dawley rats, are described. 129 Xe resonances at 0, 192, 199, and 210 ppm were observed and assigned to xenon in gas, fat, tissue, and blood, respectively. One-dimensional chemical-shift imaging (CSI) reveals xenon magnetization in the brain, kidney, and lungs. Coronal and axial two-dimensional CSI show 129 Xe dissolved in blood and tissue in the thorax. Images of the blood resonance show xenon in the lungs and the heart ventricle. Images of the tissue resonance reveal xenon in lung parenchyma and myocardium. The 129 Xe spectrum from a voxel located in the heart ventricle shows a single blood resonance. Time-resolved spectroscopy shows that the dynamics of the blood resonance match the dynamics of the gas resonance and demonstrates efficient diffusion of xenon gas to the lung parenchyma and then to pulmonary blood. These observations demonstrate the utility of laser-polarized 129 Xe to detect exchange across the gas-blood barrier in the lungs and perfusion into myocardial tissue. Applications to measurement of lung function, kidney perfusion, myocardial perfusion, and regional cerebral blood flow are discussed. Magn Reson Med 42:1137–1145, 1999. © 1999 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34928/1/19_ftp.pd

Preclincial evaluation of Gold-DTDTPA Nanoparticles As Theranostic Agents In Prostate Cancer Radiotherapy

International audienceAim: Gold nanoparticles have attracted significant interest in cancer diagnosis and treatment. Herein, we evaluated the theranostic potential of dithiolated diethylenetriamine pentaacetic acid (DTDTPA) conjugated AuNPs (Au@DTDTPA) for CT-contrast enhancement and radiosensitization in prostate cancer. Materials & methods: In vitro assays determined Au@DTDTPA uptake, cytotoxicity, radiosensitizing potential and DNA damage profiles. Human PC3 xenograft tumor models were used to determine CT enhancement and radiation modulating effects in vivo. Results: Cells exposed to nanoparticles and radiation observed significant additional reduction in survival compared with radiation only. Au@DTDTPA produced a CT enhancement of 10% and a significant extension in tumor growth delay from 16.9 days to 38.3 compared with radiation only. Conclusion: This study demonstrates the potential of Au@DTDTPA to enhance CT-image contrast and simultaneously increases the radiosensitivity of prostate tumors