Development of obesity and metabolic clinical research programs

为了实现第一个目标，我们继续完善三个大型全室间接量热套房（2008年投入使用）。除了强大的24小时能量消耗和宏量营养素氧化测量外，我们还使用基于小波的去噪算法在测量精度和灵敏度方面取得了相当大的改进。我们还为所有三个套件设计并实现了新的采样、滤波和校准系统，以延长系统寿命，减少测量误差和伪像，并提高操作效率。这些都是我们从2008财年开始要完成的工作。对于自由生活活动评估，我们成功开发了一种便携式基于加速度计的身体活动监测器的通用台式校准器。利用该仪器，我们可以全面研究不同尺寸、灵敏度、精度和量程的监测器之间和内部的变异性。

For the first aim, we continue to refine the three large-size whole-room indirect calorimetry suites (commissioned in 2008). In addition to robust 24-hr energy expenditure and macronutrient oxidation measurements, we made considerable improvements in measurement accuracy and sensitivity using a wavelet-based de-noising algorithm. We also designed and implemented new sampling, filtering, and calibration systems for all three suites to prolong system longevity, reduce measurement errors and artifacts, and improve operational efficiency. These were the work we laid out to accomplish from FY2008. For free-living activity assessments, we successfully developed a universal bench-top calibrator for portable accelerometry-based physical activity monitors. With this apparatus, we can comprehensively study the variability between and within monitors of various size, sensitivity, accuracy, and ranges. For the second aim, we developed a new clinical protocol titled Diet-Induced-Obesity Resistant Phenotypes in Humans, with the goal of identifying healthy lean subjects who are resistant to hypercaloric diets and studying their unique compensatory mechanisms for achieving energy and weight balance under 4 weeks of overfeeding (+1000 kcal/day over weight balanced diets). This protocol was approved by the IRB in August 2009 and will start accruing study participants in Oct 2009. We also launched a free-living physical activity and sleep assessment ancillary study to the Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik Study, sponsored by NIA) in March 2009. Using 100 sophisticated 3D accelerometers that we optimized in the lab, we are in the process to collect one week of activity patterns in 1000 Icelandic elderly individuals. We expected that the activity characteristics measured by the accelerometers would complement the focus on cardiovascular health, bone and muscle, metabolism, and cognitive function in this unique population.