Kitasato University 2 articles published in JoVE Environment Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera Hiroshi Muraishi1, Ryoji Enomoto2, Hideaki Katagiri3, Mika Kagaya4, Takara Watanabe5, Naofumi Narita3, Daisuke Kano5 1School of Allied Health Sciences, Kitasato University, 2Institute for Cosmic Ray Research, University of Tokyo, 3College of Science, Ibaraki University, 4National Institute of Technology, Sendai College, 5National Cancer Center Hospital East We present experimental protocols for visualizing various low-level gamma radiation sources in the ambient environment using a low-cost, high-sensitivity, omnidirectional, gamma-ray imaging Compton camera. Biology Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions Gen Kaneko1,4, Tatsuki Yoshinaga2, Kristin E. Gribble3, David M. Welch3, Hideki Ushio1 1Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 2School of Marine Biosciences, Department of Marine Biosciences, Kitasato University, 3Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, 4School of Arts and Sciences, University of Houston-Victoria Rotifers are microscopic zooplankton used as models in ecotoxicological and aging studies. Here we provide a protocol for powerful and reproducible measurement of survival time in Brachionus rotifers. Synchronization of culture conditions over several generations is of particular importance because maternal condition affects life history of offspring.