Fetal and Neonatal Goiter in Cynomolgus Monkeys Following Administration of the Antithyroid Drug Thiamazole at High Doses to Dams During Pregnancy

To evaluate morphologic alterations in the thyroid gland in the second generation in cynomolgus monkeys, pregnant dams were exposed to high doses of thiamazole. In Experiment A, dams received thiamazole intragastrically via a nasogastric catheter from gestation day (GD) 50 to GD 150 or on the day before delivery. Initially, the dose level was 20 mg/kg/day (10 mg/kg twice daily); however, the dose level was subsequently decreased to 5 mg/kg/day (2.5 mg/kg twice daily), since deteriorated general conditions were observed in two dams. Six out of seven neonates died on the day of birth. The cause of neonatal death was tracheal compression and suffocation from goiter. The transplacental exposure to thiamazole affected the fetal thyroid glands and induced goiter in all neonates. The surviving neonate was necropsied 767 days after discontinuation of thiamazole exposure and showed reversibility of the induced changes. In Experiment B, dams were intragastrically administered thiamazole at 5 mg/kg/day (2.5 mg/kg twice daily) for treatment periods from GDs 51 to 70, 71 to 90, 91 to 110, 111 to 130 and 131 to 150. All fetuses showed enlarged thyroid glands but were viable. Histopathologically, hypertrophy and/or hyperplastic appearance of the follicular epithelium of the thyroid gland was observed at the end of each treatment period. The most active appearance of the follicular epithelium, consisting of crowded pedunculated structure, was demonstrated at end of the treatment period from GD 131 to 150. This is the first report on the morphology of fetal and neonatal goiter in the cynomolgus monkey

Vision-Based Mobile Robot Speed Control Using a Probabilistic Occupancy Map

This paper describes a method of controlling the robot speed using a probabilistic occupancy map. It is usually necessary for a robot to make sure that a target region is free before entering there. If the robot is not confident the state (free or occupied) of the region, the robot has to make enough observations to be confident. If the distance to the region is long, the robot can expect to have enough observations until reaching there. If the distance is short, however, the robot may have to slow down for making enough observations. Based on this consideration, we develop a method for controlling the robot speed by considering the state of a target region. The method is applied to our mobile robot with an omnidirectional stereo and a laser range finder. The robot successfully moved around in an unknown environment with adaptively controlling its speed.

Calibration of Omnidirectional Stereo for Mobile Robots

Abstract — This paper describes a calibration method of an omnidirectional stereo system. The system uses a pair of vertically-aligned catadioptric omnidirectional cameras, each of which is composed of a perspective camera and a hyperboloidal mirror, thus providing a single projection point. We divide the calibration into two steps. The first step estimates the image center and the aspect ratio by fitting an ellipse to the mirror boundary in the image. The second step estimates the focal length and the camera pose (position and orientation) including scale by using a calibration pattern and epipolar geometry. Experimental results show the effectiveness of the proposed calibration method. I

Adaptive robot speed control by considering map and localization uncertainty

This paper describes an adaptive robot speed control method for safe and efficient navigation in unknown environments. Speed control is important in the following two cases. (1) When a robot enters a narrow free space, it needs to control the speed to avoid any collision considering the motion uncertainty. (2) When a robot enters a region whose vacancy (i.e., being free) has not been decided yet, it needs to control the speed so that it can observe the region sufficiently to be confident with the vacancy of the region. This paper proposes a simple but effective strategy for speed control that the robot selects the fastest safe speed. To adopt this strategy, we define criteria for judging whether a speed is safe for the above two cases. The proposed method successfully made the robot move around in unknown static environments with adaptively controlling the speed.