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In this paper, we establish the global asymptotic stability of equi-libria for an SIR model of infectious diseases with distributed time delays gov-erned by a wide class of nonlinear incidence rates. We obtain the global prop-erties of the model by proving the permanence and constructing a suitable Lyapunov functional. Under some suitable assumptions on the nonlinear term in the incidence rate, the global dynamics of the model is completely deter-mined by the basic reproduction number R0 and the distributed delays do not influence the global dynamics of the model.

67Gaシンチグラフィは, 悪性腫瘍のスクリーニング検査として, 広く行われている. 今回我々は, 手術で診断の確定した扁平上皮癌13例と腺癌15例について, 67Gaシンチグラフィ (プラナー像) と胸部CTによるT, N因子の示現性を比較して67Gaシンチグラフィの意義を再検討した. その結果, 67Gaシンチグラフィの腫瘤における示現性は, 扁平上皮癌が腺癌よりT因子, 病期分類共に良好であった. またN因子の正診率は, 扁平上皮癌60%, 腺癌86%で胸部CTでは, 67%, 88%で67Gaシンチグラフィと胸部CTとの間に大きな差は認めなかった. 肺非小細胞癌の術前検査として67Gaシンチグラフィは示現度の限界を熟知することにより症例を選んで行えば, 術前適応の検討に対して情報の付加が得られ, 有用な検査と考えられた.

NADH-dependent enzyme reducing acetophenone derivatives with high stereoselectivities and wide substrate specificities from Geotrichum candidum NBRC 4597 was isolated, purified, characterized, and used for asymmetric synthesis. Through five-step purification including ammonium sulfate fractionation and a series of chromatographies, the enzyme was purified about 150-fold with a yield of 5.6%. The active enzyme has a molecular mass of 73 kDa determined by gel filtration chromatography, and the SDS-PAGE result reveals that the molecular size of the subunit is 36 kDa. These results indicate that the enzyme consists of a homodimer of a 36 kDa subunit. The acetophenone reductase exhibited the highest activity at 50 degrees C and optimal pH at 5.5. The enzyme was the most stable at 40 degrees C. No metal ions considerably activated the enzyme, and such metal ions as Cu2+, Cd2+, and Zn2+ strongly inhibited the activity of the enzyme. The Vmax and the apparent Km value of the reductase were 77.0 micromol/min per milligram of protein and 0.296 mM for acetophenone, respectively. The N-terminal and internal amino acid sequences were determined by peptide sequencer. Furthermore, the purified enzyme was used for asymmetric reduction of acetophenone, resulting in the formation of corresponding (S)-alcohol with 99% ee.

The mechanical properties of methane hydrate‐bearing sand were investigated by low temperature and high confining pressure triaxial testing apparatus in the present study. The specimens were prepared by infiltrating the methane gas into partially saturated sand specimen under the given temperature and stress condition which is compatible with the phase equilibrium condition for the stability of methane hydrate. The tests were firstly performed to investigate the effect of temperature on the shear behaviour of the specimen. Then the effect of backpressure was investigated. The strength of methane hydrate bearing sand increased as the temperature decreased and the back pressure increased. The bonding strength due to methane hydrate was dependent on methane hydrate saturation, temperature and back pressure but independent of effective stress. Dissociation tests of methane hydrate were also performed by applying the temperature to the specimen at the various initial stress conditions. The marked development of shear and volumetric strains were observed due to dissociation of the methane hydrate in the specimen corresponding to the initial stress conditions.

Summary: We report 2 cases of intraspinal germinoma associated with Klinefelter syndrome. In one patient, spinal cord atrophy was observed at the upper and lower ends of the intraspinal tumor. Brain atrophy was observed in both cases. Germinoma should be included in the differential diagnosis if an intraspinal tumor is observed in a patient with Klinefelter syndrome.

To assess the image quality of multiple threshold display (MTD) as a new technique for generating three-dimensional (3D) pulmonary computed tomographic (CT) angiographic images.We used MTD, a type of shaded surface display (SSD) offering the selection of multiple thresholds and transparencies, to reconstruct 3D-CT angiograms from enhanced helical CT data sets in 33 patients with lung disease. In MTD, eight thresholds of CT values are selected, and transparency is assigned to each. The selected voxels, ranging from -600 to 1,000 Hounsfield Units, were divided into eight classes, and transparency ranging from 0 to 100% was assigned to each. The CT scanner employed was a Toshiba Xvigor. MTD and SSD images were generated by using an Xtension with a Sun SPARC station 20, and they were compared by two radiologists.The image quality of MTD images was superior to that of SSD images (p0.01), because the MTD images demonstrated clearly both the major and small vessels.MTD is a useful technique for 3D pulmonary CT angiography.