プロトタイプ型超高精細CTによる頭蓋内細動脈評価の初期臨床経験

藤田医科大

Low-Temperature X-ray Crystal Structure Analysis of the Cage-Structured Compounds MBe13 (M = La, Sm, and U)

The beryllides MBe13 (M = rare earths and actinides) crystallize in a NaZn13-type cubic structure, which can be categorized as a cage-structured compound. In this study, powder X-ray diffraction measurements have been performed on LaBe13, SmBe13, and UBe13 in the temperature range between 7 and 300 K in order to investigate their crystallographic characteristics systematically. They keep the NaZn13-type cubic structure down to the lowest temperature. We estimated their Debye temperature to be 600 - 750 K from analyses of the temperature dependence of a lattice parameter, being in good agreement with the values reported previously. Rietveld refinements on the obtained powder patterns revealed that the M atom in the 8a site is located in an almost ideal snub cube formed by 24 Be atoms in the 96i site, whose caged structure is unchanged even at the low temperatures. In addition, it is argued from the temperature variation of an isotropic mean-square displacement parameter that the MBe13 compounds commonly have a low-energy phonon mode, which can be described by a model assuming an Einstein oscillation of the M atom with a characteristic temperature of ~ 160 K.Comment: 8 pages with 6 figures and 2 table

Flight Demonstration of Electrostatic Thruster under Micro-Gravity

Based on a new concept, a low power electrostatic thruster is being developed for its application to 50 kg class satellite, which is named “Microwave Engine”. The proto-model (PM) of the microwave engine was manufactured and the qualification test (QT) was conducted. The estimated performances are 1250 seconds in specific impulse, 0.36mN in thrust and 10% in thrust efficiency when it is operated at 26.6W. To evaluate the feasibility of its accelerating mechanism, the flight demonstration of a plasma thruster is implemented under microgravity. The demonstrated thruster has an aperture of 19 mm in diameter. The same accelerating mechanism as Microwave Engine is applied to the plasma thruster although there is a difference in the mechanism of generating plasma. The flight demonstrator utilizes the glow discharge while the microwave discharge is applied to Microwave Engine. In this study, the thrust is estimated based on the flight path of the plasma thruster under microgravity, the swing of its pendulum under 1G and the beam theory of its copper wires. These corresponding thrusts are 0.36 mN, 0.20 mN and 0.11 mN, respectively. In addition, a series of its flight images is shown in this paper. As a result, the reasonable flight performance validates the accelerating mechanism of Microwave Engine

Direct Damage to a Vertebral Artery Better Predicts a Vertebral Artery Injury than Elongation in Cervical Spine Dislocation

Cervical spine dislocation and fracture of a transverse process are isolated risk factors for vertebral artery injuries (VAIs), which can cause a life-threatening ischemic stroke. Since in vivo experiments are not possible, it has not been unclear whether damage to or extension of vertebral arteries is more predictive of a VAI. To identify the imaging characteristics associated with VAI, we analyzed 36 vertebral arteries from 22 cervical spine dislocation patients who underwent computed tomography angiography (Aug. 2008-Dec. 2014). We evaluated (1) the posttraumatic elongation of the vertebral artery and (2) the presence of fracture involving the transverse foramen. VAI was found in 20 (56%) of the 36 vertebral arteries. The rate of residual shift (vertebral artery elongation) was not markedly different between the VAI and no-VAI groups. However, the rate of >1 mm displacement into the foramen and that of fracture with gross displacement (≥2 mm) differed significantly between the groups. We found that greater displacement of fractured transverse processes with cervical spine dislocation was a risk factor for VAI. These results suggest that direct damage to the vertebral arteries by transverse process fragments is more likely to predict a VAI compared to elongation, even in cervical spine dislocation

Large negative magnetoresistance in thiospinel CuCrZrS4

We report on large negative magnetoresistance observed in ferromagnetic thiospinel compound CuCrZrS$_{4}$. Electrical resistivity increased with decreasing temperature according to the form proportional to $\textrm{exp}(T_{0}/T)^{1/2}$, derived from variable range hopping with strong electron-electron interaction. Resistivity under magnetic fields was expressed by the same form with the characteristic temperature T0 decreasing with increasing magnetic field. Magnetoresistance ratio $\rho (T,0)/\rho(T,H)$ is 1.5 at 100 K for H=90 kOe and increases divergently with decreasing temperature reaching 80 at 16 K. Results of magnetization measurements are also presented. Possible mechanism of the large magnetoresistance is discussed.Comment: 9 pages, 5 figures, to be published in Solid State Commu

Continuous Operation of Micro Plasma Thruster “Microwave Engine”

A low-power, microwave-discharge type electrostatic thruster named “microwave engine” has been developed for applications to 50 kg-class satellites at Advanced Technology Institute Ltd. (ATI) in Hokkaido, Japan. A prototype of the engine was manufactured, and its performance and random vibration tests have been reported in previous papers. An endurance test followed, and showed no failure in the engine after 400 hours of operation

X-ray-induced electrical conduction in the insulating phase of thiospinel CuIr2S4

Effects of x-ray irradiation on the crystal structure and the electrical resistance were examined at low temperatures for the insulating phase of spinel compound CuIr2S4. We found that the resistance decreases by more than five decades by irradiation at 8.5 K. The structural change from triclinic to tetragonal was observed at the same time. The x-ray-induced conductance is deduced to result from the destruction of Ir4+ dimers formed in the insulating phase. Slow relaxation of the resistance in the x-ray-induced state is also reported.Comment: 18 pages with 6 figures, pdf format, to be published in Solid State Commu

Oseltamivir (Tamiflu®)-induced pneumonia

SummaryWe report the first case of oseltamivir-induced pneumonia. A 50-year-old man was diagnosed with influenza and prescribed oseltamivir. He had a persistent high fever, and developed a productive cough with peripheral blood eosinophilia and his chest radiograph showed ground glass opacity. Bronchoalveolar lavage fluid and histological findings obtained from transbronchial lung biopsy suggested eosinophilic pneumonia with component of cryptogenic organizing pneumonia. Drug lymphocyte stimulation test against oseltamivir was positive. In spite of discontinuation of oseltamivir, his condition did not ameliorate. He was treated with prednisolone for oseltamivir-induced lung injury and the symptoms improved immediately. We should recognize oseltamivir-induced pneumonia as a differential diagnosis in the case of developing pneumonia following treatment with oseltamivir