47 research outputs found
Rescue of exotropia subsequent to pulled-in-two syndrome of the medial rectus muscle occurring during surgery for high myopic strabismus fixus: A case report
Rationale: Pulled-in-two syndrome is one of the significant complications of strabismus surgery. This study aimed to report a case of pulled-in-two syndrome of the contractured medial rectus muscle (MR) that occurred during strabismus surgery for strabismus fixus due to high myopia, and to describe a rescue of this complication. Patient concerns: A woman in her 60s presented to our Ophthalmology Department with the main complaint of unilateral high myopia and severe myopic strabismus fixus. Esotropia exceeded 45° and hypotropia exceeded 15° in her right eye in the Hirschberg test. Right eye duction was markedly limited in every gaze direction. Orbital magnetic resonance images showed rupture of the superior rectus to lateral rectus band ligament and lengthening of the distance between the SR and LR muscles in the right eye. Diagnosis: Due to the patient's ophthalmic examination and imaging results, she was diagnosed with high myopic strabismus fixus. Interventions: We performed MR recession and Yokoyama surgery to correct right eye hypoesotropia. In the MR recession procedure, pulled-in-two syndrome (MR muscle tear) occurred. Thus, no additional procedure was performed on the MR. After the surgery, she presented 45 prism diopter exotropia and 18 prism diopter residual right hypotropia in a Krimsky test. We performed a second surgery, combining MR muscle advancement and inferior rectus (IR) muscle recession, 3 months after the first surgery. Outcomes: One and a half years after the second surgery, she presented exotropia of 14 prism diopters without hypotropia in the Krimsky test and was satisfied with her ocular position and improved motility. Lessons: We experienced pulled-in-two syndrome in a case with severe myopic strabismus fixus and achieved a good outcome by performing additional surgery 3 months later, in which the lost MR muscle was advanced. This case underscores that, if the lost muscle cannot be found during surgery, one should maintain composure and perform a reoperation a few months after the initial surgery, if necessary. This case report can aid in making rescue treatment decisions when pulled-in-two syndrome occurs
Early Results of a Wildfire Monitoring Microsatellite UNIFORM-1
UNIFORM (UNiversity International FORmation Mission) is a capacity building program in microsatellite field including satellites, ground stations, and data platform. The program, sponsored by the Ministry of Education, Culture, Sports and Technology (MEXT) of Japan, aims to increase the number of players in the small satellite community through education of both domestic and international young engineers, by providing them with an opportunity to study, build, and operate microsatellites. The first satellite of the program, UNIFORM-1 was launched on May 24th 2014. UNIFORM-1 is a 50-kg earth observation satellite whose mission is wildfiremonitoring using a microbolometer. Since then it has been in operation, successfully capturing several events on the ground including wildfires and volcanic activities. This paper presents in-orbit results of UNIFORM-1 mission, critical bus subsystems including EPS and AOCS, and lessons learned from its operations
UNIFORM-1: First Micro-Satellite of Forest Fire Monitoring Constellation Project
UNIFORM Project had started in November 2010 with its vision of constructing sustainable micro-satellite constellation system via cooperation with various countries. International collaboration and actual utilization of the system are the keys of the project for realizing sustainable space industry. Forest fire monitoring was selected as the first mission. UNIFORM-1 is the first micro-satellite, weighing 50kg with 50cm cubic size, in this project and launched on May 24th, 2014 by H-IIA rocket as a secondary payload. UNIFORM-1 carries two cameras of area sensor: uncooled microbolometer camera and visible light camera. Both have GSD of less than 200[m] and swath is about 100km. These two cameras are used for localization of heat anomaly spots. The acquired image will be overlaid on global map to generate a “forest fire map” which will be released so that local fire department of the concerning country can take action promptly and extinguish forest fire. Other key features of this satellite are following: 3-axis control with reaction wheels, deployable solar array panel wings, lithium ion battery, and 10Mbps X-band transmitter for mission data. Design and test result of UNIFORM-1 flight model is explained in detail in this paper. As the result of initial operation of five days after launch, image of infrared camera was successfully acquired
UNIFORM-1 Ground System: Mission Planning, Scheduling, Control, and Data Processing
Mission planning and scheduling is an essential part of satellite operations, and traditional satellites have a big, complex ground system which takes care of their operations planning, resource allocation, scheduling, and so on. As small satellites become more and more complex, their capability have been increased and so has the need of proper planning and control; it is necessary to have a good planning system in order to maximize the functionality of a small satellite by effectively and efficiently utilize its resource. This paper discusses the ground software developed for UNIFORM-1 satellite. The ground software consists of mission planning/scheduling, mission control center, and operations data distribution. All the downlinked operations data are stored in a database and will be used for analyzing the satellite conditions as well as extracting information necessary for addressing when/how much mission data acquisition is available. Combined with the request from the end-user (i.e., those who need to monitor specific target area on Earth for wildfire surveillance), achievable mission plans will be generated. Those operations plans include when image capture will take place, when those data will be downlinked to the ground, etc., and will be automatically converted to operations procedures which is comprehensible by the TT&C software at the control center (MCC). This paper also presents the actual operations plans and the corresponding data obtained from the early-phase operations of UNIFORM-1