Ozone fading of phenolphthalein and aurin

The reactions of phenolphthalein, which exists as a lactone-quinonoid tautomeric mixture in solution, and aurin with ozone have been examined. The reactivity of the lactone tautomer of phenolphthalein with ozone was found to be low and the ozone attacks the aromatic ring. In the case of the quinonoid tautomer the ozone readily reacts with the carbon skeleton. In the case of aurin ozone also attacks the carbon skeleton.     

Management for subarachnoid hemorrhage with negative initial angiography

The diversity of neuronal glutamate receptors continues to increase with the discovery of multiple subunits and subunit families. The significance of this potential receptor heterogeneity is unknown because pharmacological tools that could clearly distinguish between different structural isoforms have not yet been identified. A novel glutamate receptor antagonist, 5-nitro-6,7,8,9-tetrahydrobenzo[g]indole-2,3-dione-3-oxime (NS-102), has been shown previously to selectively block the low affinity [3H]kainate binding site in rat brain. We have examined the effect of NS-102 on receptors expressed in fibroblasts from either glur6 subunits or a combination of glurB and glurD (glurB/D receptors). NS-102 (3 microM) reduced currents mediated by glur6 receptors and had very little effect on currents mediated by glurB/D receptors. The binding of [3H]kainate to glur6 receptors showed properties similar to those of the brain low affinity [3H]kainate binding site, and NS-102 inhibited specific binding to glur6 receptors with a potency nearly identical to those sites in brain membranes. Our findings suggest that NS-102 will be useful in identifying the functional role of native receptors containing a glur6 subunit.     

A radioimmunometric assay for urinary alpha 2-macroglobulin

To measure urinary alpha 2-macroglobulin levels, a sensitive radioimmunometric assay was established. The least detectable level of this assay was 225 pg/ml. A linear correlation between alpha 2-macroglobulin levels and serial dilution of urine samples was found. Western blot analysis and study on column chromatography revealed that the molecular weight of alpha 2-macroglobulin in urine was identical to that of serum alpha 2-macroglobulin. The findings suggested that urinary substance detected by the present assay was truly alpha 2-macroglobulin. Timed overnight urine samples from 49 diabetic patients with retinopathy and 20 healthy controls were measured by the present assay. Patients were classified as Albustix-negative and Albustix-positive patients. The highest urinary alpha 2-macroglobulin excretion rates (alpha 2-MER) was found in Albustix-positive patients followed by Albustix-negative patients and the healthy controls. In view of the fact that the stroke radius of alpha 2-macroglobulin (88A) is larger than that of the restrictive pore (56A), the present finding suggests that leakage of alpha 2-macroglobulin in urine may be induced by defect of non-discriminatory pores in the glomerular basement membrane proposed by Deen and colleagues.     

Mutual signal gain saturation in Er/sup 3+/-doped fibre amplifier around 1.54 mu m wavelength

Signal gain saturation characteristics of a 1.48 mu m wavelength laser diode pumped Er/sup 3+/-doped fibre amplifier are experimentally investigated for two signal channels amplified around the gain peak wavelengths of 1.535 mu m and 1.551 mu m. The degree of gain saturation is uniquely determined by the total output power when the signal wavelengths are closely positioned. This feature is not suited to two-channel amplification for widely spaced wavelengths.<>     

100-channel optical FDM transmission/distribution at 622 Mbit/s over 50 km utilising a waveguide frequency selection switch

100-channel optical FDM transmission/distribution at 622 Mbit/s is demonstrated for a fibre length of 50 km. A polarisation-insensitive waveguide frequency-selection-switch with 10 GHz intervals and an FSK/direct-detection scheme using a Mach-Zehnder filter type optical frequency discriminator are verified as feasible.<>     

The effect of anions on the electrochemical reduction of thick oxide films on platinum electrode in acidic aqueous solutions

The cathodic galvanostatic reduction of thick oxide films on Pt has been studied in HF, HClO₄ and H₂SO₄ solutions at 25°C as a function of the current density and the concentration of these acids.The thick oxide film was found to be completely reduced at a single potential step of 0.6 V (vs rhe in the test solution) in HF solution and also in very dilute HClO₄ and H₂SO₄ solutions. However, when the oxide was slowly reduced in these solutions except HF solution, the charging curve exhibited two well-defined potential arrests. That is, as the reduction current was decreased, the first arrest at 0.6 V shifted slightly towards positive potential, but the second arrest moved remarkably in negative direction. The same shift of the second arrest was observed when the solution was agitated or the acid concentration was increased. The potential shift of the second arrest is attributed to blocking the reduction of the inner-layer oxide by anions adsorbed on the bare surface which was formed by the reduction of the outermost monolayer oxide at the first arrest potential. The effect of HSO₄^? on the reduction of the inner-layer oxide was stronger than that of ClO₄^?, and the effect of F^? was very weak.     

Generalized Stochastic Sampling Method for Visualization and Investigation of Implicit Surfaces

Recently we proposed the stochastic sampling method (SSM), which can numerically generate sample points on complicated implicit surfaces quickly and uniformly. In this paper we generalize the method in two aspects: (1) We introduce two kinds of boundary conditions, so that we can sample a finite part of an open surface spreading infinitely. (2) We generalize the stochastic differential equation used in the SSM, so that its solutions can satisfy plural constraint conditions simultaneously. The first generalization enables us to visualize cut views of open surfaces. The second generalization enables us to visualize intersections of static and moving implicit surfaces, which leads to detailed investigation of intersections and other interesting applications such as visualization of contour maps.