Study of ground-tunnel interactions of four shield tunnels driven in close proximity, in relation to design and construction of parallel shield tunnels

In Japan, K yoto City has constructed four subway tunnels that run closely each other. Problems accompanying the closely running tunnels are studied during the planning and design stages prior to construction. A variety of monitoring during the construction stage resulted in the collection of numerous data including the load transmission between tunnels and characteristic behavior of theground during the construction of four tunnels. Aiming at improving the method for the evaluation of the interaction of closely running tunnels, this study attempted to analyze and assess the behavior of the tunnels and the surrounding ground through such data obtained from the above project. This paper describes the characteristics of influence from the thrust of a succeeding tunnel to a preceding tunnel and the analytical expression of the mechanism of ground behavior during the construction of closely running tunnels.     

1.3 μm InGaAs/GaAs strained quantum well lasers with InGaPcladding layer

Using MOVPE, we fabricated strained quantum well 1.3 μm lasers with an InGaP cladding layer on a GaAs substrate. The lasers had a high gain coefficient of 60 cm^-1. Lasers with high reflection facets had a low threshold current density of 500 A/cm², and a high characteristic temperature of 100 K     

Plasma-Activated Sintering of Aluminum Nitride

The use of a new plasma- activated sintering (PAS) process to densify aluminum nitride (AIN) powders to nearly full theoretical density (97 to >99%) in 5 to 10 min was investigated. The process consists of a pulse activation step, followed by sintering at 1730 to 1800 °C using resistance heating in carbon dies. Submicron size (~0.44 μm) AIN powders of low oxygen content (<1 wt%) were consolidated to near full density in both air and vacuum with no sintering aids or binders. Transmission electron microscopy (TEM) examination revealed an equiaxed, submicron grain structure (~0.77 μm) with no apparent pores or intergranular phases. X- ray powder diffraction revealed no secondary crystalline phases.     

Self-diffusion of cadmium in cadmium telluride annealed in tellurium-saturated atmosphere

Diffusion behavior of Cd in volume and along dislocations in high-purity CdTe annealed in Te-saturated atmosphere has been studied by the radioactive tracer method with a serial ion-beam sputter-microsectioning technique. The temperature dependence of volume diffusion coefficients shows a bend around 773 K, whereas that of the self-diffusion along dislocations shows a straight line. This suggests that the defect induced by impurities enhances the volume diffusion but does not affect the diffusion along dislocations.     

The accuracy of localizing equivalent dipoles and thespatio-temporal correlations of background EEG

For the inverse problem of equivalent dipole localization, a new residual function was proposed which is based on spatio-temporal correlation of background electroencephalogram (EEG). This residual has the advantage that it allows the calculation of a confidence region for estimated dipole parameters. This method was applied to two sets of visual evoked potential (VEP) data. The localization was compared by using the volume of the confidence region. The outcome of the equivalent dipole localization was compared for three different residual functions: 1) least square; 2) based on spatial correlations in the background EEG; and 3) the proposed new function which is based on spatial and temporal correlations in the background EEG. It was found that the proposed residual function leads the authors to the highest accuracy and the fastest convergence in the equivalent dipole localization and that even for two-dipole localization, the present method yields more accurate solutions with less iterations than the conventional methods     

Spinal root avulsion-induced upregulation of osteopontin expression in the adult rat spinal cord

Osteopontin (OPN) is a secretory adhesive glycoprotein that is expressed in various tissues and plays a role in inflammation and tissue repair. It has been suggested that OPN plays a role in inflammation and wound healing after spinal cord injury; however, the expression of OPN and its function in the spinal cord under normal conditions and following spinal motoneuron injury have not been well characterized. Here we examined the expression of OPN mRNA before and after spinal root avulsion. OPN mRNA was detected at a low level in the normal spinal cord in a Northern blot analysis, but dramatically increased following avulsion. In situ hybridization and immunohistochemical studies demonstrated that OPN was present only in a subset of spinal motoneurons before avulsion. After avulsion, the number of OPN-expressing motoneurons increased, although the total number of motoneurons was reduced. OPN expression also became apparent in activated microglia/macrophages and astrocytes. These data suggest that the upregulation of OPN after spinal root avulsion is involved in two events, the protection of neurons and the post-traumatic inflammatory response in microglia/macrophages and astrocytes.     

Organic compounds with heteroatoms as overcharge protection additives for lithium cells

Various organic compounds with heteroatoms (N, O, F, Si, P, S) were tested as overcharge protection additives for 4-V class lithium cells. It was found that trimethyl-3,5-xylylsilane exhibited preferable oxidation potential (E_ox) as overcharge protection additive, and charge–discharge cycling efficiency (Eff) of lithium anode in electrolyte with arylsilanes was as high as tolyladamantanes, reported previously by us. From room temperature to 60 °C, E_ox of trimethyl-3,5-xylylsilane decreased only 0.07 V. Difference in E_ox among regioisomers of tolyltrimethylsilanes is smaller than that among tolyladamantanes. ¹H NMR and UV spectra suggest the steric repulsion between tolyl group and trimethylsilyl group in o-tolyltrimethylsilane is smaller than that of the related substituents of o-tolyladamantane.     

Association of high-altitude pulmonary edema with the major histocompatibility complex

BACKGROUND: A constitutional susceptibility has been suggested in the development of high-altitude pulmonary edema (HAPE) because HAPE generally affects healthy young people, some of whom suffer recurrent episodes. We examined whether immunogenetic susceptibility is present in HAPE-susceptible subjects. METHODS AND RESULTS: The frequencies of human leukocyte antigen (HLA) alleles in 28 male and 2 female subjects with a history of HAPE were compared with those in 100 healthy volunteers. We assayed the HLA-A, -B, -C, -DR, and -DQ antigens serologically. The pulmonary hemodynamics on admission to the hospital and the ventilatory response to hypoxia and hypercapnia were retrospectively examined in 10 of the HAPE-susceptible subjects. HLA-DR6 was positive in 14 (46.7%) of the subjects with HAPE but only 16.0% of the control subjects (P=.0005), and HLA-DQ4 was positive in 12 (40.0%) of the subjects with HAPE but only 10.0% of the control subjects (P=.0001). HLA-DR6 or HLA-DQ4 was positive in 8 (100%) of the subjects with recurrent HAPE. The pulmonary arterial pressure on admission of the HLA-DR6-positive subjects with HAPE was significantly higher than that of the HLA-DR6-negative subjects with HAPE. CONCLUSIONS: There were significant associations of HAPE with HLA-DR6 and HLA-DQ4 and of pulmonary hypertension with HLA-DR6. An immunogenetic susceptibility, which is associated with HLA class II alleles located within the major histocompatibility complex, may underlie the development of HAPE, at least in some of its forms.