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Measurements in phantoms are used to predict temperature changes that would occur in vivo for medical implants due to the radio frequency (RF) field in magnetic resonance imaging (MRI). In this study, the impact of concentration of the gelling agent in a saline-based phantom on the RF-induced temperature rise was measured using an apparatus that accurately reproduces the RF environment present in a 1.5-T whole-body MR system. The temperature was measured using fluoroptic thermometry at the electrode and other sites for a deep brain neurostimulation system. The average power deposition in the 30-kg phantom was about 1.5 W/kg. Four phantom formulations were evaluated, using different concentrations of polyacrylic acid (PAA) added to saline solution, with NaCl concentration adjusted to maintain an electrical conductivity near 0.24 S/m. The greatest temperature rises occurred at the electrode, ranging from 16.2 [degrees]C for greatest concentration of PAA to 2.9 [degrees]C for only saline solution. The temperature rise attained the maximal value for sufficient concentration of PAA. Similar behavior was observed in the temperature versus time relationship near a current-carrying resistor, immersed in gel and saline, which was used to model a localized heat source. The temperature rise for insufficient PAA concentration is reduced due to convection of phantom material. In conclusion, an appropriate gelling agent is required to accurately simulate the thermal properties of body tissues for measurements of RF-induced heating with medical implants. Index Terms--Deep brain stimulation, heating, magnetic resonance imaging (MRI), medical implant, radio frequency.

BACKGROUND: The declining myogenic potential of aged skeletal muscle is multifactorial. Insufficient satellite cell activity is one factor in this process. Notch and Wnt signaling are involved in various biological processes including orchestrating satellite cell activity within skeletal muscle. These pathways become dysfunctional during the aging process and may contribute to the poor skeletal muscle competency. Phytoecdysteroids are natural adaptogenic compounds with demonstrated benefit on skeletal muscle. AIM: To determine the extent to which a phytoecdysteroid enriched extract from Ajuga turkestanica (ATE) affects Notch and Wnt signaling in aged skeletal muscle. MATERIALS AND METHODS: Male C57BL/6 mice (20 months) were randomly assigned to Control (CT) or ATE treatment groups. Chow was supplemented with either vehicle (CT) or ATE (50 mg/kg/day) for 28 days. Following supplementation, the triceps brachii muscles were harvested and immunohistochemical analyses performed. Components of Notch or Wnt signaling were co-labelled with Pax7, a quiescent satellite cell marker. RESULTS: ATE supplementation significantly increased the percent of active Notch/Pax7+ nuclei (p = 0.005), Hes1/Pax7+ nuclei (p = 0.038), active B-catenin/Pax7+ nuclei (p = 0.011), and Lef1/Pax7+ nuclei (p = 0.022), compared to CT. ATE supplementation did not change the resting satellite cell number. CONCLUSIONS: ATE supplementation in aged mice increases Notch and Wnt signaling in triceps brachii muscle. If Notch and Wnt benefit skeletal muscle, then phytoecdysteroids may provide a protective effect and maintain the integrity of aged skeletal muscle. [ABSTRACT FROM AUTHOR]

Abstract Background Obesity increases the risk of endometrial cancer (EC) and obese EC patients have the highest risk of death among all obesity-associated cancers. However, only two lifestyle interventions targeting this high-risk population have been conducted. In one trial, food disinhibition, as determined by the Three-Factor Eating Questionnaire, decreased post-intervention compared to baseline, suggesting an increase in emotional eating and, potentially, an increase in food related reward. Therefore, we evaluated appetitive behavior using functional magnetic resonance imaging (fMRI) and a visual food task in 8 obese, Stage I/II EC patients before and after a lifestyle intervention (Survivors in Uterine Cancer Empowered by Exercise and a Healthy Diet, SUCCEED), which aimed to improve nutritional and exercise behaviors over 16 group sessions in 6 months using social cognitive theory. Results Congruent to findings in the general obese population, we found that obese EC patients, at baseline, had increased activation in response to high- vs. low-calorie food cues after eating a meal in brain regions associated with food reward (insula, cingulate gyrus; precentral gyrus; whole brain cluster corrected, p Conclusions Our preliminary results suggest behavioral lifestyle interventions may help to reduce high-calorie food reward in obese EC survivors who are at a high-risk of death. To our knowledge, this is the first study to demonstrate such changes.