Detection of relative and uniform motion

We measured the lowest velocity (velocity threshold) for discriminating motion direction in relative and uniform motion stimuli, varying the contrast and the spatial frequency of the stimulus gratings. The results showed significant differences in the effects of contrast and spatial frequency on the threshold, as well as on the absolute threshold level between the two motion conditions, except when the contrast was 1% or lower. Little effect of spatial frequency was found for uniform motion, whereas a bandpass property with a peak at approximately 5 cycles per degree was found for relative motion. It was also found that contrast had little effect on uniform motion, whereas the threshold decreased with increases in contrast up to 85% for relative motion. These differences cannot be attributed to possible differences in eye movements between the relative and the uniform motion conditions, because the spatial-frequency characteristics differed in the two conditions even when the presentation duration was short enough to prevent eye movements. The differences also cannot be attributed to detecting positional changes, because the velocity threshold was not determined by the total distance of the stimulus movements. These results suggest that there are two different motion pathways: one that specializes in relative motion and one that specializes in uniform or global motion. A simulation showed that the difference in the response functions of the two possible pathways accounts for the differences in the spatial-frequency and contrast dependency of the velocity threshold.     

Development of simple and efficient in Planta transformation method for wheat (Triticum aestivum L.) using Agrobacterium tumefaciens

Wheat (Triticum aestivum L. var. Shiranekomugi) seeds were soaked in water at 22 degrees C for 1 d. Thereafter, the embryo of the soaked seeds was inoculated with Agrobacterium tumefaciens by piercing a region of the embryonic apical meristem with a needle that had been dipped in an A. tumefaciens inoculum. The inoculated seeds were incubated at 22 degrees C for 2 d and sterilized by cefotaxime (Claforan) (1000 ppm water solution) treatment and then vernalized at 5 degrees C for 25 d. Finally, the seedlings were grown to maturation (T(0) plants) and allowed to pollinate naturally for seed setting (T(1) plants) in pots under nonsterile condition. To examine the transformation by various means, four different strains of A. tumefaciens were used for transformation. The following five lines of evidence proved the transformation: altered phenotype and its transmittance to the next generation, resistance of T(1) seed germination to geneticin or hygromycin B, the detection of a transgene in T(1) plants by PCR analysis and Southern hybridization and the rescue of the plasmid consisting of the integrated T-DNA and flanking wheat genome DNA from T(1) plants. The transformation efficiency of T(1) plants, which were transformed using different A. tumefaciens strains, was estimated to be 33% by PCR analysis, 75% by Southern hybridization and 40% by plasmid rescue.     

Nonlinear two-stage model for color discrimination

We modified a two-stage model for color discrimination proposed in a previous study [Color Res. Appl.25, 105 (2000)]; in order to extend the model to wider conditions, we considered the conditions with luminance modulations in addition to color modulations. Using the modified model, we successfully predicted color discrimination data with test color changes along both the chromatic and luminance axes under a variety of background colors. Both qualitative and quantitative assessments in modeling showed that nonlinearity is required in both the cone and the cone-opponent stages to interpret adaptation effects of both color and luminance on color discrimination. This fact suggests that the nonlinear properties at each stage have different roles in color perception.     

Decreased brain intracellular pH measured by 31P-MRS in bipolar disorder: a confirmation in drug-free patients and correlation with white matter hyperintensity

Special procedures were developed to investigate poisonous milk of lactating goats fed experimentally on aerial parts of the herb Euphorbia peplus L. In extracts of the milk, weakly irritant in the mouse-ear assay, three diterpene ester toxins were detected by techniques of high-performance liquid chromatography. They are of the ingenane structural type: Euphorbia factor Pel (ingenol 20-acetate 3-angelate), Euphorbia factor Pe2 (20-deoxyingenol 3-angelate) and Euphorbia factor Pe4 (20-deoxyingenol-6alpha,7alpha-epoxide 3-angelate). From goats milk collected 15 days after cessation of the experimental feeding period, extracts were completely free of diterpene ester toxins. The toxins polluting the milk are identical to diterpene ester entities occurring in the aerial parts of E. peplus. Of these, Euphorbia factors Pel and Pe2 are known as promoters of tumors of mouse skin. Apart from the toxic Euphorbia factors, the non-toxic parent alcohol ingenol was also detected in the milk. It is absent in the plant, and may have been generated metabolically from a certain portion of the toxic diterpene esters picked up by the goats from their fodder. The results presented here provide, for the first time, data for a novel interpretation of the locally high incidence of esophageal cancer observed in certain areas in the Caspian littoral of Iran, associated with a greater consumption of goat's (and sheep's) milk.     

Effect of photic stimulation on energy metabolism in the human brain measured by 31P-MR spectroscopy

Effect of photic stimulation (PS) on energy metabolism in the human occipital cortex was examined by using phosphorus-31 magnetic resonance spectroscopy in 9 normal subjects. Phosphocreatine (PCr)/total phosphorus signal peak area ratio significantly decreased from 12.3% to 10.9% during the 12 minutes of PS (P < 0.05). PCr once returned to a normal level after PS (11.9%) but significantly decreased again 12-18 minutes after PS (10.8%; P < 0.05). Intracellular pH increased from 7.08 to 7.16 during PS, although this increase was not significant. These results suggest that functional alteration of energy metabolism in the brain is different from that in muscles.     

Insulation characteristics of vacuum interrupter for a new 72/84 kVC-GIS

This paper describes insulation technology for 72/84 kV vacuum interrupter for a new cubicle-type gas insulated switchgear (CGIS). The insulation performance has been increased significantly by a multi-gap shield configuration around the ceramic surface, which resulted in a 40% volume reduction of the vacuum interrupter. The CGIS housing the vacuum interrupter also reduced by 40% in volume. In the paper, the authors describe the basic characteristics on surface insulation and the area effect on surface insulation and their application to an new 72/84 kV CGIS     

Development of simple and efficient in planta transformation method for rice (Oryza sativa L.) using Agrobacterium tumefaciens

Seeds of rice (Oryza sativa L. var. Koshihikari) were soaked in water for 2 d. Thereafter, the embryo containing an apical meristem was inoculated with Agrobacterium tumefaciens by piercing a site of the husk overlying the embryonic apical meristem with a needle that had been dipped in an A. tumefaciens inoculum. The inoculated seeds were then grown to maturation (T0 plants) and allowed to pollinate naturally to set seeds (T1 plants) in pots under nonsterile conditions. To examine the transformation by various means, three different strains of A. tumefaciens were used for transformation: an M-21 mutant, which is an avirulent mutant with a Tn5 insertion in the iaaM gene, and two LBA4404 strains each with a different binary vector. Five different lines of evidence were demonstrated the transformation: the altered phenotype and its inheritance by the next generation, histochemical detection of beta-glucuronidase, resistance to hygromycin B, detection of the transgene by PCR and rescue of a plasmid consisting of the integrated T-DNA and the flanking rice genome DNA. Transformation efficiency of T1 plants was estimated to be 40% and 43% by PCR and a histochemical assay of beta-glucuronidase, respectively.     

Influence of surface roughness on the charging of insulating spacers in vacuum

This paper describes the charging phenomena of cylindrical insulators made of PMMA, PTFE, or Al₂O₃ under ramped and stepped dc voltage. It is primarily concerned with the influence of surface roughness on the formation of charging for various insulating spacers. By using an electrostatic probe located on the cathode, we conducted real‐time observations of the electric field induced by the surface charge. It was found that the surface roughness positively affects the charging, which becomes more pronounced in insulators polished to a higher degree. Furthermore, polished insulators are characterized by a shorter time lag. These results show the importance of surface treatment for insulating spacers in vacuum. © 2001 Scripta Technica, Electr Eng Jpn, 135(3): 16–25, 2001     

Investigation of dielectric breakdown characteristics of double‐break vacuum interrupter and dielectric breakdown probability distribution in vacuum interrupter

To investigate the reliability of equipment of vacuum insulation, a study was carried out to clarify breakdown probability distributions in a vacuum gap. Further, a double‐break vacuum circuit breaker was investigated for breakdown probability distribution. The test results show that the breakdown probability distribution of the vacuum gap can be represented by a Weibull distribution using a location parameter, which shows the voltage that permits a zero breakdown probability. The location parameter obtained from Weibull plot depends on electrode area. The shape parameter obtained from Weibull plot of vacuum gap was 10 to 14, and was constant irrespective of the nonuniform field factor. The breakdown probability distribution after no‐load switching can be represented by Weibull distribution using a location parameter. The shape parameter after no‐load switching was 6 to 8.5, and was constant irrespective of the gap length. This indicates that the scatter of the breakdown voltage was increased by no‐load switching. If the vacuum circuit breaker uses a double break, the breakdown probability at low voltage becomes lower than the single‐break probability. Although the potential distribution is a concern in the double‐break vacuum circuit breaker, its insulation reliability is better than that of the single‐break vacuum interrupter even if the bias of the vacuum interrupter's sharing voltage is taken into account. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(2): 13–20, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21060