Development of miniaturized pick-up amplification circuit for plasma particle detectors on board satellites

Plasma particles and waves are important observation targets in space plasmas for understanding the mechanisms of energy and momentum transfer between waves and particles because space plasmas are essentially collisionless. Multi-point observations are crucial for understanding the spatial–temporal variations of space plasmas. To realize such observations by a large number of satellites, onboard instruments should be miniaturized to reduce their required resources. This paper proposes a small amplifier for plasma particle detectors onboard satellites. This charge-sensitive amplifier converts an electron cloud emitted from the detector, for example a microchannel plate, to a current pulse that can be handled by a time-of-flight measurement circuit to determine the particle velocity and thus mass. The amplifier is realized using application-specific integrated circuit technology to minimize size. Its dimensions are estimated to be $$2120, mathrm{ mu m }times 1680, mathrm{ mu m}$$, which are much smaller than those of a conventional amplifier. The response time of the proposed amplifier has a variation of less than $$1.2, mathrm{ ns}$$ over the range of expected input levels. The amplifier can handle up to $$2times {10}^{7}$$ signals per second and has a sensitivity of $$1.5, mathrm{ V}/mathrm{pC}$$ at $$20, mathrm{^circ{rm C} }$$

A Proposal of the Fingerprint Optimization Method for the Fingerprint-Based Indoor Localization System with IEEE 802.15.4 Devices

Nowadays, human indoor localization services inside buildings or on underground streets are in strong demand for various location-based services. Since conventional GPS cannot be used, indoor localization systems using wireless technologies have been extensively studied. Previously, we studied a fingerprint-based indoor localization system using IEEE802.15.4 devices, called FILS15.4, to allow use of inexpensive, tiny, and long-life transmitters. However, due to the narrow channel band and the low transmission power, the link quality indicator (LOI) used for fingerprints easily fluctuates by human movements and other uncontrollable factors. To improve the localization accuracy, FILS15.4 restricts the detection granularity to one room in the field, and adopts multiple fingerprints for one room, considering fluctuated signals, where their values must be properly adjusted. In this paper, we present a fingerprint optimization method for finding the proper fingerprint parameters in FILS15.4 by extending the existing one. As the training phase using the measurement LQI, it iteratively changes fingerprint values to maximize the newly defined score function for the room detecting accuracy. Moreover, it automatically increases the number of fingerprints for a room if the accuracy is not sufficient. For evaluations, we applied the proposed method to the measured LQI data using the FILS15.4 testbed system in the no. 2 Engineering Building at Okayama University. The validation results show that it improves the average detection accuracy (at higher than 97%) by automatically increasing the number of fingerprints and optimizing the values

A case of rectal Dieulafoy's ulcer and successful endoscopic sclerotherapy.

A 54-year-old woman presented a massive hematochezia 7 days after sigmoidectomy. Repeated colonoscopy and angiography failed to locate the site of bleeding and Hartman's operation was performed. Rebleeding from the rectum on the day of operation occurred and pulsate arterial bleeding with minimal surrounding ulcer 1 cm above the pectinate line was observed. Screlotherapy with ethanol and electro coagulation was successfully performed to achieve permanent hemostasis. The importance of detailed rectal examination and an awareness of this clinical entity in life-threatening lower intestinal bleeding is discussed.</p

Endoscopic sphincterotomy assisted by percutaneous transhepatic choledochal tube: a preliminary report

We report a method of endoscopic retrograde sphincterotomy in patients in whom the optimal viewing of the papilla of Vater is hardly obtained. Percutaneous transhepatic cholangiodrainage (PTCD)-tube is placed under ultrasonographic guidance. PTCD-tube coming out of the papilla of Vater is observed by the endoscope and the guide wire inside the shpincterotome is inserted into the PTCD-tube. Sphincterotome is advanced into the common bile duct by the guidance of the guide wire and PTCD-tube. Sphincterotomy is performed in a usual fashion. Two patients with previous history of gastrectomy underwent this procedure with successful results. This method should be tried when usual method of EST is difficult and unsuccessful.</p

Endoscopic submucosal tumor biopsy using Stiegmann-Goff endoscopic ligator.

Endoscopic biopsy is an important tool for histological diagnosis of lesions residing in gastrointestinal tracts. However, it is less useful in submucosal lesions due to the existence of normal overlying mucosa. We developed a new and safe technique for the diagnosis of submucosal tumor using Stiegmann-Goff endoscopic ligator. After removing surface mucosa to expose submucosal tissue by this method, conventional secured histological diagnosis could be performed. To determine definitive histological diagnosis, this technique is useful as well as Endoscopic Ultrasound (EUS) with fine needle aspiration biopsy and other modalities.</p

A case of traumatic neuroma of the gallbladder in the absence of previous surgery and cholelithiasis.

We experienced a patient with traumatic neuroma of the gallbladder with no history of gallbladder surgery or cholelithiasis. A 74-year-old man was referred to our department after a gallbladder tumor was incidentally discovered during a preoperative screening examination for prostate hypertrophy. Ultrasonography, MRI, CT and endoscopic retrograde cholangiography revealed a protuberant lesion of the gallbladder. Laparoscopic cholecystectomy was attempted but adhesion between the liver and duodenum forced us to convert to open laparotomy. Cholecystectomy and adjacent liver tissue resection was performed. Diagnosis was made by frozen histology during operation. It revealed no malignancy. Postoperative pathological examination revealed traumatic neuroma associated with inflammation. To our knowledge, this is the first reported case of gallbladder neuroma without a history of gallstones or surgery in the English and Japanese literature since 1980. This traumatic neuroma should be considered in a differential diagnosis in treating gallbladder neoplasm, even in the absence of an operative history or cholelithiasis.</p

Endobronchial Ultrasound-guided Transbronchial Needle Aspiration for the Diagnosis of Intrathoracic Lesions : Experience of a Single Academic Medical Center

Article信州医学雑誌 60(5): 249-255(2012)journal articl

The Hyper Suprime-Cam SSP survey: Overview and survey design

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey