日本における小児急性脳炎脳症の疫学的特徴

Imma Tubella est présidente de l’université ouverte de Catalogne (Open University of Catalonia, UOC) à Barcelone.  Elle est professeur en communication et titulaire de la chaire « Nouvelles technologies et éducation » au Collège d’études mondiales. Auparavant, elle a été vice-présidente de l’Institut des études catalanes de la communication (1995-2003) et directrice des études à la Catalan Radio and Television Corporation (1995-2002). Tout en poursuivant ses recherches dans ce domaine, elle c..

SIC/SIC composite thruster for a non-toxic liquid propellant rocket engine

Combustion chamber and nozzle for a non-toxic liquid rocket engine made by Tyrano ZMI SiC fiber reinforced SiC matrix composite were tested under sea level combustion tests. Combustion chamber and nozzle are the key hot parts for small liquid propellant engine, since chamber wall needs to be cooled by fuel rich low temperature gas. To create fuel rich low temperature gas, excess amount of fuel is consumed. Consequently, high temperature heat resisting material is indispensable to have better performance rocket engine. Nb based alloy are commonly used in combustion chamber and nozzle for a liquid propellant rocket engine for a satellite maneuver system with the maximum operating temperature around 1300°C. In this study, SiC/SiC combustion chamber with nozzle were examined and its performance was demonstrated by sea level static combustion tests in air and under vacuum. Tyrano ZMI SiC fiber (Ube Industry) was used as reinforcing fiber and carbon interface was selected to have higher temperature resistance. Fiber preform was fabricated by tri-axial braiding technique and carbon interface and SiC matrix were formed by chemical vapor infiltration (CVI). After CVI process, further densification was conducted by polymer infiltration and pyrolysis (PIP) process until no gas leak was detected under low pressure of 0.2 MPa. Largest inner diameter of the chamber was designed as 65 mm and the smallest inner diameter of 26 mm as a nozzle throat. Nozzle was designed with opening area ratio of 25 to investigate manufacturability. The combustion chamber and nozzle attached with a core engine as shown in Figure 1. Non-toxic fuel, ethanol, and oxidizer, N2O, were supplied through the showerhead type injection into combustion chamber. Sea level static combustion tests were conducted both in air and under vacuum (1.3 kPa). The engine combustion tests were successful (30s in air and 19 s in vacuum) and no damage could be found. The performance of the engine improved to specific impulse of 290s with assumption of nozzle area ratio 100. The maximum surface temperature reached to 1250°C, where the inner wall temperature could be calculated about 1600°C. Prototype engine development program successfully completed and we are preparing to start real application project of this engine system as a final stage of solid propellant satellite launcher Please click Additional Files below to see the full abstract

マスター方程式と離散拡散方程式の関係―離散幾何学による解析―

ISM Online Open House, 2020.10.27統計数理研究所オープンハウス（オンライン開催）、R2.10.27ポスター発

Bisphosphonate use is associated with a decreased joint narrowing rate in the non-arthritic hip

AIMS: The preventive effects of bisphosphonates on articular cartilage in non-arthritic joints are unclear. This study aimed to investigate the effects of oral bisphosphonates on the rate of joint space narrowing in the non-arthritic hip. METHODS: We retrospectively reviewed standing whole-leg radiographs from patients who underwent knee arthroplasties from 2012 to 2020 at our institute. Patients with previous hip surgery, Kellgren-Lawrence grade ≥ II hip osteoarthritis, hip dysplasia, or rheumatoid arthritis were excluded. The rate of hip joint space narrowing was measured in 398 patients (796 hips), and the effects of the use of bisphosphonates were examined using the multivariate regression model and the propensity score matching (1:2) model. RESULTS: A total of 45 of 398 (11.3%) eligible patients were taking an oral bisphosphonate at the time of knee surgery, with a mean age of 75.8 years (SD 6.2) in bisphosphonate users and 75.7 years (SD 6.8) in non-users. The mean joint space narrowing rate was 0.04 mm/year (SD 0.11) in bisphosphonate users and 0.12 mm/year (SD 0.25) in non-users (p < 0.001). In the multivariate model, age (standardized coefficient = 0.0867, p = 0.016) and the use of a bisphosphonate (standardized coefficient = -0.182, p < 0.001) were associated with the joint space narrowing rate. After successfully matching 43 bisphosphonate users and 86 non-users, the joint narrowing rate was smaller in bisphosphonate users (p < 0.001). CONCLUSION: The use of bisphosphonates is associated with decreased joint degeneration in non-arthritic hips after knee arthroplasty. Bisphosphonates slow joint degeneration, thus maintaining the thickness of joint cartilage in the normal joint or during the early phase of osteoarthritis.Cite this article: Bone Joint Res 2022;11(11):826-834

Epidemiology of Pediatric Acute Encephalitis/Encephalopathy in Japan

We studied the etiology of pediatric acute encephalitis/encephalopathy (pAEE) using epidemiological data obtained from a nationwide survey in Japan. Two-step questionnaires were sent to the pediatric departments of hospitals throughout the country in 2007, querying the number of the cases during 2005-2006 as the first step, and asking for the details of clinical information as the second step. In all, 636 children with pAEE (age ≤ 15 years) were enrolled. For the known etiology of pAEE (63.5% of the total cases), 26 microbes and 2 clinical entities were listed, but the etiology of 36.5% remained unknown. Influenza virus (26.7%), exanthem subitum (12.3%), and rotavirus (4.1%) were the most common, and the incidence of pAEE peaked at the age of 1 year. This trend was common among all etiologies. Among the neurological symptoms observed at the onset of pAEE, seizures were observed more often in patients aged ≤ 3 years, although abnormal speech and behavior were also common in older children. Undesirable outcomes (death and neurological sequelae) occurred at high rates in patients with any known etiology other than mycoplasma. In conclusion, these findings provide comprehensive insight into pAEE in Japan

Changes in the Corneal Endothelium of Aphakic Patients Following Extended Soft Contact Lens Wear

The contact lenses used for visual correction of aphakia are mostly soft contact lenses for extended wear because most aphakic patients are elderly. The effects of extended wear of such contact lenses on corneal endothelial cells have been recently reported. In this study, two groups, an extended wear SCL group and a spectacles group, were compared with respect to various parameters by means of specular microscopy following surgery for cataract. The SCL group consisted of 16 subjects and 16 eyes. The average age at operation was 67.8 years and the wearing period was 1 to 5 years after operation. The spectacles group consisted of 14 subjects and 16 eyes; the average age at operation was 70.1 years, and the wearing period was 1 to 5 years after surgery. Using a wide field specular microscope (mode1 SP-1), endothelial cells in the central part of the cornea were observed and photographed. The endothelial cell picture was then enlarged to a final magnification of 450 times, and the image was analyzed using the KC-8VA cell analyzer system. There was no significant difference in the mean cell area (μm2) and mean cell density (cell counts/mm2) between the two groups, but the coefficient of variation (CV) was significantly elevated in the SCL group after operation. The percentage of hexagonal cells was also significantly lower in the SCL group after operation. Therefore extended wear of soft contact lenses appears to make corneal endothelial cells unstable and accelerates changes in cornet endothelial cells due to aging

Glucose Metabolism in Cataractous Lens

Since the sorbitol pathway in the lens of a diabetic rat was discovered, the relation between cataract formation and aldose reductase has been studied. We measured glucose, sorbitol and fructose in the human cataractous lens by the gaschromatography. Additionally, we measured sugar and polyols in bovine, pig and rabbit lens. The ratio of sorbitol/glucose is high in rabbit, pig and bovine lens in order. In the human cataractous lens, glucose is increased in accordance with development of cataract. On the other hand, sorbitol content is high in the diabetic lens and low in the senile cataractous lens. The aldose reductase inhibitor may have beneficial effects in the prevention of diabetic cataract formation, but have not the therapeutic effect in the senile cataract

Reduced marine biogenic sulphate flux in East Antarctica during glacial periods - Based on ion chemistry records from Dome Fuji ice core -

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / 2F Auditorium, National Institute of Polar Researc