Regulation of insulin responsiveness in rat hepatoma cells

Insulin causes a 5 to 10-fold increase in the velocity of [alpha]-aminoisobutyric acid transport and a 2 to 3-fold increase in tyrosine aminotransferase activity in dexamethasone-treated hepatoma tissue culture cells. Maximal responses occur 2-4 hours after insulin addition but then decrease to control levels by 24 hours incubation. Medium conditioned by cells incubated with insulin for 24 hours retains sufficient biologically active insulin to produce an insulin response in fresh dexamethasone-treated cells. Readdition of insulin to insulin-treated cells, however, elicits no response, indicating that the cells are insensitive to the hormone. Incubation of such unresponsive cells in the absence of insulin results in recovery of responsiveness within 2 hours. These data suggest that exposure of rat hepatoma cells to insulin causes a complete but reversible loss of sensitivity to this hormone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23316/1/0000255.pd

Present and Future of SLAM in Extreme Underground Environments

This paper reports on the state of the art in underground SLAM by discussing different SLAM strategies and results across six teams that participated in the three-year-long SubT competition. In particular, the paper has four main goals. First, we review the algorithms, architectures, and systems adopted by the teams; particular emphasis is put on lidar-centric SLAM solutions (the go-to approach for virtually all teams in the competition), heterogeneous multi-robot operation (including both aerial and ground robots), and real-world underground operation (from the presence of obscurants to the need to handle tight computational constraints). We do not shy away from discussing the dirty details behind the different SubT SLAM systems, which are often omitted from technical papers. Second, we discuss the maturity of the field by highlighting what is possible with the current SLAM systems and what we believe is within reach with some good systems engineering. Third, we outline what we believe are fundamental open problems, that are likely to require further research to break through. Finally, we provide a list of open-source SLAM implementations and datasets that have been produced during the SubT challenge and related efforts, and constitute a useful resource for researchers and practitioners.Comment: 21 pages including references. This survey paper is submitted to IEEE Transactions on Robotics for pre-approva

Regulation of testicular LH receptors by homologous hormone: studies on receptor occupancy and receptor loss

A method is described which makes use of 4M MgCl2 to dissociate the testicular luteinizing hormone-receptor complex without altering either the binding capacity or binding affinity of the receptor. Using this method, it was demonstrated that incubation at 4[deg] of decapsulated rat testes with various concentrations of luteinizing hormone or with human chorionic gonadotropin resulted in a reduction in binding capacity. This reduction of binding capacity could not be completely accounted for by occupation of receptors by homologous hormone, suggesting that receptors were lost. Thus negative regulation of LH receptors by LH and hCG was observed. The reduction in LH binding capacity was specific for LH and hCG, dose dependent and time related. FSH, prolactin and growth hormone did not exert the same effect.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22979/1/0000546.pd

Wildcat: Online Continuous-Time 3D Lidar-Inertial SLAM

We present Wildcat, a novel online 3D lidar-inertial SLAM system with exceptional versatility and robustness. At its core, Wildcat combines a robust real-time lidar-inertial odometry module, utilising a continuous-time trajectory representation, with an efficient pose-graph optimisation module that seamlessly supports both the single- and multi-agent settings. The robustness of Wildcat was recently demonstrated in the DARPA Subterranean Challenge where it outperformed other SLAM systems across various types of sensing-degraded and perceptually challenging environments. In this paper, we extensively evaluate Wildcat in a diverse set of new and publicly available real-world datasets and showcase its superior robustness and versatility over two existing state-of-the-art lidar-inertial SLAM systems.Comment: 13 pages, 18 figure

Findings from a Combined Subsea LiDAR and Multibeam Survey at Kingston Reef, Western Australia

Light Detection and Ranging (LiDAR), a comparatively new technology in the field of underwater surveying, has principally been used for taking precise measurement of undersea structures in the oil and gas industry. Typically, the LiDAR is deployed on a remotely operated vehicle (ROV), which will “land” on the seafloor in order to generate a 3D point cloud of its environment from a stationary position. To explore the potential of subsea LiDAR on a moving platform in an environmental context, we deployed an underwater LiDAR system simultaneously with a multibeam echosounder (MBES), surveying Kingston Reef off the coast of Rottnest Island, Western Australia. This paper compares and summarises the relative accuracy and characteristics of underwater LiDAR and multibeam sonar and investigates synergies between sonar and LiDAR technology for the purpose of benthic habitat mapping and underwater simultaneous localisation and mapping (SLAM) for Autonomous Underwater Vehicles (AUVs). We found that LiDAR reflectivity and multibeam backscatter are complementary technologies for habitat mapping, which can combine to discriminate between habitats that could not be mapped with either one alone. For robot navigation, SLAM can be effectively applied with either technology, however, when a Global Navigation Satellite System (GNSS) is available, SLAM does not significantly improve the self-consistency of multibeam data, but it does for LiDAR