Early effects of gamma knife radiosurgery on brain metastases: assessment by 201TlCl SPECT and 99mTc-DTPA-human serum albumin SPECT

Thallium-201 chloride (201TlCl) single photon emission computed tomography (SPECT) was used to determine tumor viability, and the early and delayed images of technetium-99m-diethylenetriaminepenta-acetic acid-human serum albumin (99mTc-HSA-D) SPECT were used to assess tumor vascularity and permeability, respectively, in 17 patients with 18 brain metastases. SPECT was performed before, 1 week after, and 1 month after radiosurgery. The ratios of 201Tl and 99mTc-HSA-D uptake in a tumor were expressed as a ratio to uptake in the corresponding normal contralateral areas (uptake index). Magnetic resonance imaging with gadolinium was used to determine tumor volume. 201Tl index decreased significantly 1 week (p < 0.05) and 1 month (p < 0.005) after radiosurgery. In contrast, 99mTc-HSA-D indices of early and delayed images obtained at 1 week after radiosurgery were not significantly different from the pretreatment values. However, both were significantly low (p < 0.05) 1 month after radiosurgery. No change in tumor volume was detected 1 week following radiosurgery, but there was a significant decrease (p < 0.005) after 1 month. The reduction in tumor viability that occurs before the appearance of evidence of tumor shrinkage represents the early effect of radiosurgery on brain metastases. Reduction in tumor size, vascularity, and permeability occur subsequently.     

Computer-Based Discrimination of Abnormal Stomachs Using Radiograms

The possibility of automating mass screening of gastric disease was studied by applying statistical pattern recognition methods to features extracted from standing position-anteroposterior radiograms by two approaches. A region of interest was defined to encompass the deformity of the apex or the sulcus angularis. The ability of the features to classify normal, ulcerated, and cancerous cases was evaluated by a typical method of discriminant analysis, the minimum Mahalanobis distance classification. The error classification rate was estimated by the leaving-one-out method. Best feature sets were selected by the forward sequential search. The separability of the samples and the properties of the features were inspected also by cluster analysis. For the selected feature sets, the error classification rate obtained by the discriminant analysis agreed well with results of the cluster analysis and of inspection by physicians. The selected features tended to belong to different feature clusters. This seems to validate the feature selection.     

Studies on the toxicity of pulp and paper mill effluents—II. Mutagenicity of the extracts of the liver from spotted sea trout (Nibea mitsukurii)

Sediment samples collected at three different coastal points (Shinguu, Ooigawa and Tagonoura) were extracted with diethylether and then methanol. Each extract was separated into five fractions by high-speed liquid chromatography and they were submitted to mutagenic assay using B. subtilis and S. typhimurium and to GC-MS analysis.The ether fraction of sediment sample from Shinguu showed DNA damaging potency on B. subtilis and exhibited mutagenic effect on S. typhimurium TA 98, TA 100 and TA 1537. 2,4,6-Trichlorophenol, 3,4,5,6-tetrachloroguaiacol, dehydroabietic acid, pyrene and fluoranthene were mutagenic substances among 28 substances identified and tested.     

Projection‐type integral 3‐D display with distortion compensation

Abstract— Our research is aimed at developing a spatial‐imaging‐type integral three‐dimensional (3‐D) display based on an integral photography method using an extremely high‐resolution projector. One problem with the projection‐type integral 3‐D display is that geometrical distortion in projected elemental images causes spatial deformation of the displayed 3‐D image. In this study, a general relationship between the geometric distortion of elemental images and the spatial deformation of reconstructed 3‐D images were analyzed. A projection‐type integral 3‐D display with a distortion compensator which corrects the geometrical distortions of projected images in real‐time have been developed. The deformation of the displayed 3‐D images was significantly reduced by the distortion compensation, and the displayed 3‐D images had a resolution of 182 (H) × 140 (V) pixels and a viewing angle of 24.5°.     

Cavity length dependence of differential quantum efficiency of GaInAsP/InP lasers

The cavity length dependence of the differential quantum efficiency ?d of 1.58 ?m wavelength GaInAsP/InP buried heterostructure lasers was investigated theoretically and experimentally. Theoretical calculations of ?d taking intervalence band absorption into account is in agreement with the measured results, in which ?d increases with decreasing the cavity length. The maximum value of ?d obtained was 53% for the cavity length of 100 ?m in pulsed operation at room temperature.     

Alloy composition and flow rates in GaxIn1?xAsyP1?y lattice-matched to InP grown by MO-CVD

Relations between alloy compositions and flow rates of sources in TEG/TEI/AsH3/PH3/H2 LP-MOCVD system for the growth of GaInAsP/InP were experimentally studied under lattice-matching and high crystalline quality enough for laser oscillation. A proportional relationship was observed between the alloy of Ga/In and source of TEG/TEI, As/P and AsH3/PH3 over the bandgap wavelength of 1.3?1.6 ?m.     

Dislocation-Induced Softening of MgO·2.9Al2O3 Single Crystals

Magnesium aluminate spinel (MgO·2.9Al₂O₃) single crystals were deformed in compression along the [001] direction at temperatures between 1100° and 1500°C. Dislocations introduced by plastic deformation were observed by transmission electron microscopy. These dislocations lead to plasticity at a temperature where undeformed spinel has no ductility. Further, room-temperature Vickers hardness decreases after plastic deformation at 1500°C.     

A relationship between electrical conductivity and photodegradation in styrene-butadiene copolymer/multi-wall carbon nanotube composite

An effect of photodegradation on electrical conductivity of a styrene-butadiene copolymer (SBR)/multiwall carbon nanotube (MWNT) composite was studied with a TiO₂/polyethylene oxide/methyl linoleate paint photocatalyst under UV and/or visible light irradiation. An oxidative etching of impurities on the MWNT surface was caused by the UV or visible light irradiation, leading to an increase of quality of MWNT. On the other hand, the photocatalyst addition caused the degradation of MWNT structure. A relationship between the electrical conductivity and MWNT content showed that the MWNT dispersity in a SBR was superior to that in a polystyrene (PS). In addition, the PS addition to SBR matrix caused MWNT aggregation. The electrical conductivity decrease of the MWNT composite was due to electrical percolation structure loss caused by the photocatalyst under the visible light irradiation, and its rate depended on the MWNT dispersity. The PS molecular weight change behavior with the photocatalyst was consistent with the electrical conductivity one of the SBR/MWNT. The photocatalyst ability was estimated from the electrical conductivity of the SBR/MWNT.     

Synthesis of β-MoO3 nanowhiskers from core/shell molybdenum/molybdenum oxide wire by pulsed wire discharge

β-MoO_3, the molybdenum oxide phase with the highest catalytic activity, is a promising material in optical, chemical, and electronics applications as a replacement for α-MoO₃. α-MoO₃ 1D nanostructures such as whiskers and fibers have been investigated and used in applications. However, difficulties in the synthesis of one-dimensional β-MoO₃ have obstructed researchers in the study of its properties. In this research, β-MoO₃ nanowhiskers were synthesized from core/shell molybdenum/molybdenum oxide wires by pulsed wire discharge in mixed oxygen and argon gases. X-ray diffraction analysis identified the main phase in the obtained samples as β-MoO₃. Electron microscopy observations revealed whiskers with an average length and width of 216 nm and 23 nm, respectively. Transmission electron microscopy lattice imaging confirmed the successful synthesis of β-MoO₃ nanowhiskers. Various models were considered to explain the formation of β-MoO₃ nanowhiskers, including mechanical fragmentation of α-MoO₃ layers as well as vapor-liquid-solid and vapor-solid mechanisms. The phase transformation from α to β-MoO₃ under a nucleation process was explained based on the Mo-O phase diagram. To the best of our knowledge, this is the first report of β-MoO₃ nanowhisker synthesis.     

Impact of Pd nanoparticle loading method on SnO2 surface for natural gas detection in humid atmosphere

To improve the sensor response to low concentrations of methane (CH₄) at low operating temperatures in humid atmospheres, we prepared Pd-loaded SnO₂ (Pd-SnO₂) nanoparticles via two different Pd-loading processes: (i) a general impregnation method and (ii) a new loading method using poly(N-vinyl-2-pyrrolidone) (PVP) as a protective agent for Pd receptor particles. According to the measured electric resistances, the Pd particles limited the hydroxyl-poisoning of the SnO₂ particle surface. Because Pd is oxidized to PdO, a p–n junction is formed at the interface between PdO and SnO₂, and such interface gives the enlargement of the electron depletion layer. Therefore, Pd further improved the resistance against hydroxyl poisoning of the SnO₂ surface in humid air. In addition, although the sensor based on neat SnO₂ did not respond to low-concentration CH₄ at 200–400 °C, both the sensors based on the Pd-loaded SnO₂ samples exhibited high sensor response to 200 ppm CH₄ in a humid atmosphere. The Pd-SnO₂ obtained by the new loading method exhibited a higher response to CH₄ at lower concentrations in the lower operating temperature range (200–250 °C). This improvement in the sensor response is probably due to the catalytic activity of the larger Pd nanoparticles. According to high-resolution transmission electron microscopy–energy-dispersive X-ray spectroscopy images, the new loading method successfully provided Pd-loaded SnO₂ nanoparticles with Pd nanoparticles dispersed uniformly on the SnO₂ particle surface. The average particle size of Pd nanoparticles loaded on the surface of SnO₂ by the new loading method was slightly larger than that of the Pd nanoparticles loaded by the impregnation method. As the Pd particle size increases, it is thought that crystalline PdO particles are formed more easily, thereby improving the combustion activity of CH₄ under humid conditions. These results are of great significance for further decreasing the energy consumption of the CH₄ sensor and increasing its sensor response in humid atmospheres.