A facile transformation of Arabidopsis thaliana using ceramic supported propagation system

Arabidopsis thaliana can be a useful model plant in the field of plant molecular biology because it is a sole dicotyledonous plant whose genome sequence has been completely determined at the present time. To develop functional genomics of A. thaliana, a large number of transgenic plants must be produced. However, transformation of the plants requires wide space and long time. For these reasons, a highly efficient method has been desired to be developed. In order to save space, the transformation system was improved, based on a new technology for plant propagation using ceramic tubes. The new method using ceramic tubes facilitated to prepare plants with a uniform growth level. In addition, the colander procedure after infiltration, which is one of tedious procedures, could be omitted. The new system without soil usage could cut down the cleaning up after experiment.     

Polycyclic aromatic hydrocarbons in indoor and outdoor environments and factors affecting their concentrations

A highly sensitive analytical method for the simultaneous determination of 39 gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) was used to determine the PAH composition of indoor and outdoor air in Shimizu, Japan. In both indoor and outdoor air, gaseous PAH concentrations were higher in summer than in winter, whereas particulate PAH concentrations were higher in winter than in summer. Correlation analysis indicated that indoor PAH compositions, especially the gaseous PAH composition, differed significantly from outdoor PAH compositions. Gaseous PAH concentrations indoors were significantly affected by insect repellents and heating sources. Particulate PAH concentrations indoors were significantly affected by cigarette smoking, the age and type (wood) of the house, and outdoor PAH concentrations. Inhalation risk associated with carcinogenic PAHs was estimated by using toxic equivalency factors based on the potency of benzo[a]pyrene (BaP). The carcinogenicity of the indoor PAH mixture was dominated by naphthalene followed by BaP and dibenz[a,h]anthracene.     

Dipolar Field Effect on Microwave Oscillation in a Domain-Wall Spin Valve

In this paper, we examined dipolar field effects on the microwave generation in the domain-wall spin valve by solving simultaneously the Landau-Lifshitz-Gilbert and Zhang-Levy-Fert diffusion equations. By numerically analyzing dipolar field dependence, we showed that the microwave generation needs the dipole-dipole interaction for a 180^deg domain wall and the amplitude of the microwave voltage signal depends strongly on the exchange length. In order to design a microwave generator using the domain-wall spin valve with high efficiency, we propose that the materials with short exchange length are preferred.     

PCM Jitter Suppression by Scrambling

Jitter suppression in a chain of baseband PCM repeaters is studied. It is shown that a scrambler is very effective for systematic jitter suppression and that beyond 5 stages little additional suppression results. The probability of mark in the scrambler output converges to 0.5, independently of that in the input PCM signal. Experimental results confirm the analysis and show the ability of the scrambler to reduce the systematic jitter. The timing information disappearance of PCM repeatered lines when the scrambler is applied is also discussed.     

Statistical analysis of ice fracture characteristics

This paper addresses the fracture toughness and strength characteristics of ice taken from Notoro Lagoon in the Okhotsk Sea close to Hokkaido. Experimental values of tensile and bending strengths, and fracture toughness of sea ice conformed to Weibull statistical distribution. The proposed model predicts variation in fracture toughness as a function of the statistical distribution of ice grain sizes, effective surface energy, and elastic constants of ice. A very good agreement between experimental cumulative probability of fracture toughness and predicted distribution of fracture toughness of sea ice has been found. Computing the Weibull stress of sea ice, the dependence of fracture probability on stress intensity factor has been established. This result is in very good agreement with the presented method for the prediction of fracture toughness of sea ice.     

Mechanism of the combined anti-bacterial effect of green tea extract and NaCl against Staphylococcus aureus and Escherichia coli O157:H7

The mechanism of the combined anti-bacterial effect of green tea extract (GTE) and NaCl against Staphylococcus aureus NBRC 13276 and Escherichia coli O157:H7 was investigated. After treatment for 1 h, GTE was more effective against S. aureus than E. coli O157:H7, and combined GTE/NaCl treatment caused greater cellular damage in S. aureus NBRC 13276, where it was bactericidal, than E. coli O157:H7. Compared to treatment with 1.0 mg/mL GTE, which had no effect on the survival rate of E. coli O157:H7 after 48 h, treatment with 4% NaCl alone caused greater cellular damage. Moreover, bacteria pretreated with NaCl showed delayed growth in the presence of GTE. It is therefore likely that susceptibility of E. coli O157:H7 to GTE was increased by exposure to NaCl. E. coli O157:H7 pretreated with GTE and NaCl did not multiply in the presence of GTE. Visualization of the catechin components of GTE-treated bacteria using an electron microscope and SDS-PAGE analysis of cell proteins showed that GTE attached to proteins on the surface of the bacteria to form high-molecular weight complexes, suggesting the possibility that GTE inhibits the uptake and secretion of substrates and inhibits enzyme activity. Notably, after the GTE treatment for 1 h, both bacterial strains suffered injury but recovered by cultivation in rich medium. The damage and aggregation of proteins caused by GTE treatment were repaired upon treatment with LP diluent.     

Identification of peak bone mass QTL in a spontaneously osteoporotic mouse strain

The whole genome scan for quantitative trait loci (QTLs) specifying peak bone mass was performed with the F2 intercrosses of SAMP6, an established murine model of senile osteoporosis, exhibiting a significantly lower peak bone mass, and SAMP2, exhibiting a higher peak bone mass. Cortical thickness index (CTI), a parameter of bone mass of femurs, was measured in 488 F2 progeny at 4 months of age, when the animals attained peak bone mass by microphotodensitometry. Genetic markers were typed at 90 loci spanning all chromosomes except the Y. By interval mapping of 246 male F2 mice, two loci were identified with significant linkage to peak bone mass, one on Chromosome (Chr) 11 and another on Chr 13, with a maximum lod score of 10.8 (22.2% of the total variance) and 5.8 (10.0%), respectively. Another locus on the X Chr was suggestive of a QTL associated oppositely with a low peak bone mass to the SAMP2 allele. This association was consistent with the distribution of peak bone mass in the F1 and F2. These findings should be useful to elucidate the genetics of osteoporosis.