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著者人数：70名, 資料番号: SA1002290000

Due to the establishment in recent years of neuroendoscopic third ventriculostomy (ETV), it has become possible during ETV to observe the ventral brainstem surface--particularly the prepontine cistern--in a minimally invasive manner via the third ventricular base with a neuroendoscope. As an adaptation of that technique in this study, we investigated a neuroendoscopic trans-third ventricle approach (ETTVA), which accesses lesions of the ventral brainstem surface with a neuroendoscope inserted via the stoma of the third ventricular floor. Our study included 6 cases, including one case each of neurenteric cyst, chordoma, pontine glioma (astrocytoma), ecchordosis physaliphora, endodermal cyst, and cystic schwannoma. Surgical operations performed by ETTVA included 3 cases of tumor resection, 2 cases of tumor biopsy, and 1 case of cyst puncture and aspiration. There were no complications accompanying ETTVA. Out of the 6 cases, only 1 required additional surgical treatment following ETTVA surgery. In the other 5 cases, no additional surgical procedures were performed. This study showed that ETTVA allowed access to the prepontine cistern quickly and in a minimally invasive manner. In selected cases, ETTVA can offer a new approach to these lesions.

We reported a case of posterior mediastinal mature teratoma. A 16-year-old woman was referred for further investigation of a left paravertebral mass detected on chest roentgenogram. The defined mass was located above the diaphragm and showed homogeneous fat density on computed tomography (CT) and hypersignal intensity on both T1 weighted images and T2 weighted images on magnetic resonance imaging (MRI). Radiologically, there was a mimicking foci of calcification. The mass was histologically diagnosed as mature teratoma.

A 68-year-old male, pointed out of bilateral lung tumors, was hospitalized for the evaluation of multiple lung tumors. Chest computed tomography demonstrated 10 x 10 mm and 30 x 60 mm tumors in left lower lung and a 16 x 16 mm tumor in right lower lung. He was operated under the diagnosis of intracranial meningioma 26-years ago. For purpose of diagnosis, partial resections of left lower lung were performed, and then these tumors were diagnosed as pulmonary metastasis of intracranial meningioma. This is a very rare case of pulmonary metastasis of meningioma 26-years after craniotomy.

Compression modulus and strength have been measured for unidirectional carbon fiber/thermoplastic matrix composites Values obtained from the use of a Northrop loading fixture are compared to those from an IITRI fixture Low Northrop modulus values are explained using buckling theory and the effect of fiber curvature within the lam inate. Also, data are compared tor composites with different fiber forms with emphasis on fiber curvature.

Small-angle light scattering was employed as a nondestructive technique for the in situ observation of swelling of PVC particles during gelation and fusion. One typical plastisol grade of PVC and three different plasticizers were used. The results demonstrate that quantitative measurements of average PVC particle size appear possible while they are in the process of swelling with plasticizers. From the degree of swelling the solvent power of plasticizers may be evaluated. The ranking of plasticizers made in this manner was in good agreement with the previous studies involving viscoelastic measurements.

The authors describe the concept of a composite interferometric light intensity modulator constructed in the form of a cascade of 2/sup n/ branched-waveguide electrooptic modulators in which the DC bias of the individual modulators are provided in a certain phasing required to yield a high overall modulation efficiency. The analysis of this cascaded modulator, presented in the scattering matrix formalism, predicts that the overall modulation efficiency of the cascade is increased by the factor 2/sup n/2/ compared with that of a single constituent modulator when both are supplied with the same amount of modulating signal power. >

The super hi-vision (SHV) developed by NHK is an ultrahigh-definition video system with 4000 scanning lines. Its video format comprises 7680times4320 pixels, which is 16 times the total number of pixels of HDTV (high definition television) and the frame rate is 60 Hz with progressive scanning. It has been designed to give viewers a strong sense of reality. In order to make the system suitable for practical use such as broadcasting services, a high-efficiency compression coding system is necessary. Therefore, we have developed several super hi-vision codec systems based on MPEG-2 and AVC/H.264 video coding standards. SHV video signals are converted to sixteen HDTV signals and each video signal is processed by HDTV codec. The codec systems share some characteristics such as the frame synchronized encoding function. In this paper, details of these codec systems are described and transmission experiments using the codec are introduced.

A 52-year old female with anomalous systemic arterial supply to pulmonary sequestration was reported. The patient was admitted because of an abnormal lung shadow on chest X-ray film. Computed tomography (CT) showed an anomalous systemic arterial supply to pulmonary sequestration of the left lower lung without lung infection. Video-assisted thoracoscopic surgery for ligation of the anomalous systemic artery was performed. Postoperative course has been uneventful for 14 months after surgery. Blood supply increased to the left lower lung by 3-dimensional CT after surgery. The ligation of anomalous systemic arterial is enough for this disease.

Along with the development of wearable computers or wearable interface for portable communications, authors are focusing on the research to the applications of wearable equipment. Currently, the wearable computer is required to have same performance as those of conventional PC. However, there are limitations in the capability of I/O devices. Furthermore, it is not easy for a person to use these devices when he/she is walking or doing something. Therefore, this paper proposes and presents a wearable "Personal Assistant" tool featuring simple human interface.

A 63-year-old female, who had undergone a modified radical mastectomy for breast cancer at the age of 45, was suffered from trachyphonia due to left recurrent nerve paralysis at the age of 53. She presented left phrenic nerve paralysis and dysphagia at the age of 61. Computed tomography (CT) revealed mediastinal fibrosis, stenosis of esophagus and superior vena cava, and slight lymph nodes swelling. Video-assisted thoracoscopic mediastinal biopsy was performed and the mediastinal fibrosis was diagnosed as recurrence of breast cancer 17 years after the breast cancer operation. She underwent mediastinal radiation and chemotherapy for mediastinal recurrence and stenting for esophageal stenosis.

The achievable accuracy for estimating the position of a mobile station (MS) in terms of the Cramer-Rao lower bound (CRLB) has been well studied and accepted. For certain class of layouts of an MS and base stations (BS), termed as ill-conditioned layouts here, the CRLB suggests that the variance of estimation errors is infinitely large. In this paper, we investigate how to overcome this problem in both analytical and algorithmic aspects. The ill-conditioned layouts are classified into two categories: layouts with an insufficient number of BS and those satisfying the condition of collinearity or coplanarity. We investigate estimation schemes and error analysis for each category. Accordingly, a geolocation method with adaptive dimensions is devised. Simulation results confirm the effectiveness of our method.

Nb/sub 3/Al has potential capability in realizing a TF coil that can produce a magnetic field up to around 16 T because of the inherently high critical current at high field and less sensitivity against strains. Mass production technique of Nb/sub 3/Al strands was therefore established in 1990s and about 1 ton of strands were produced by the authors. Then, coil fabrication technique was developed and a large coil, the Nb/sub 3/Al insert, was fabricated. In addition, the prototype Nb/sub 3/Al conductor for JT-60 superconducting tokamak has already been developed. The test results of these coils demonstrate applicability of the Nb/sub 3/Al conductor to TF coil with react-and-wind method. The possibility of developing TF coils whose operating field is around 16 T seems to be promised through these successive results.

On-site underground background measurements were performed for the planned reactor-neutrino oscillation experiment KASKA at Kashiwazaki-Kariwa nuclear power station in Niigata, Japan. A small-diameter boring hole was excavated down to 70m underground level, and a detector unit for $\gamma$-ray and cosmic-muon measurements was placed at various depths to take data. The data were analyzed to obtain abundance of natural radioactive elements in the surrounding soil and rates of cosmic muons that penetrate the overburden. The results will be reflected in the design of the KASKA experiment., Comment: 9 pages, 7 figures, final version for publication. Table 1 and Fig.5 have changed

Nonlinear evolutions of MHD instabilities in the large helical device are studied by means of direct numerical simulations under the vacuum configuration with the magnetic axis position R = 3.6m, including effects of its full three‐dimensional geometry, flows parallel to the magnetic field lines and the fluid compressibility. The linear growth of the pressure‐driven modes and their nonlinear saturations are observed. The linear growth brings about the flows parallel to the magnetic field lines as strong as the perpendicular flows. The fluid compressibility reduces the linear growth rate significantly. In the nonlinear saturation process, a qualitative difference is found in the behaviors of the parallel and perpendicular flows. The plasma appears to approach to a near‐equilibrium state, keeping finite amplitudes of the parallel flow. Our numerical results highlight important roles of the parallel flow and compressibility in nonlinear MHD simulations in the large helical device.

The ICRF heating in toroidal plasmas is studied using two global simulation codes: a full wave field solver TASK/WM and a drift kinetic equation solver GNET. The codes are applied to both tokamaks and helical systems. The full wave code TASK/WM evaluates the realistic wave electric field, in which the effect of the self‐consistent non‐Maxwellian velocity distribution on the wave propagation is taken into account. GNET solves a linearized drift kinetic equation (5D phase‐space) for energetic ions including complicated behavior of trapped particles in helical systemsCharacteristics of energetic ion distributions in the phase space are investigatedSelf‐consistent analysis including the effect of energetic ion distribution on the fast wave propagation is also reported for tokamak plasmas.