Determination and Evaluation of Sampling Velocity in a Simple Passive Sampling Method to Monitor HNO3(g) in Ambient Air

We evaluated the applicability of a simple passive sampling method to quantify HNO₃(g) in ambient air. The method has the advantages of not only ease of operation but also low cost. A sampling velocity of 214 m day^?1 was determined based on the concentration of HNO₃(g) measured by the four-stage filter-pack method at nine sites located within a 250?×?250-km area in Japan. This sampling velocity was applied at sites located outside of area to verify the applicability and accuracy of the simple passive sampling method. The variation in the results for the application of the sampling velocity ranged from 0.39 to 0.95. The simple passive sampling method should be applied to sites with different meteorological conditions, and the obtained data should be used to obtain more significant information and/or to indicate the need for further developments in the methodology.     

Effect of decay on shear performance of dowel-type timber joints

Monotonic and reversed cyclic loading tests were conducted on dowel-type timber joints with varying degrees of wood decay due to Fomitopsis palustris (Berk. et Curt.), a brown rot fungus, and the effect of decay on various shear performances of dowel-type joints was investigated. For joints affected by the brown rot fungus, the initial stiffness, yield load, and maximum load of dowel-type joints were significantly decreased, even with a small mass loss of wood. The reductions in shear performance were the largest for initial stiffness, followed by yield load and maximum load, in that order. For a 1% reduction of the yield load, initial stiffness and maximum load showed reductions of 1.15% and 0.77%, respectively. When dowel-type joints that had been exposed to the brown rot fungus were subjected to reversed cyclic loading, the gap between the dowel and the lead hole of the wood was increased and equivalent viscous damping was decreased. These results indicate that decay around the dowel lead hole especially affects the load-displacement behavior at small displacement level, and dowel-type joints under cyclic loading have very low resistance to forces acting on the wooden structure. Part of this report was presented at the 5th Symposium on Timber Bridges of the Japan Society of Civil Engineers, Tokyo, July 2006; the 56th Annual Meeting of the Japan Wood Research Society, Akita, August 2006; and the Annual Meeting of the Architectural Institute of Japan, Fukuoka, August 2007     

Cloning of the pathogenicity-related gene <Emphasis Type="Italic">FPD1</Emphasis> in <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">lycopersici</Emphasis>

We selected a reduced-pathogenicity mutant of Fusarium oxysporum f. sp. lycopersici, a tomato wilt pathogen, from the transformants generated by restriction enzyme-mediated integration (REMI) transformation. The gene tagged with the plasmid in the mutant was predicted to encode a protein of 321 amino acids and was designated FPD1. Homology search showed its partial similarity to a chloride conductance regulatory protein of Xenopus, suggesting that FPD1 is a transmembrane protein. Although the function of FPD1 has not been identified, it does participate in the pathogenicity of F. oxysporum f. sp. lycopersici because FPD1-deficient mutants reproduced the reduced pathogenicity on tomato.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB110097     

Transient uplift after a 17th-century earthquake along the Kuril subduction zone

In eastern Hokkaido, 60 to 80 kilometers above a subducting oceanic plate, tidal mudflats changed into freshwater forests during the first decades after a 17th-century tsunami. The mudflats gradually rose by a meter, as judged from fossil diatom assemblages. Both the tsunami and the ensuing uplift exceeded any in the region's 200 years of written history, and both resulted from a shallow plate-boundary earthquake of unusually large size along the Kuril subduction zone. This earthquake probably induced more creep farther down the plate boundary than did any of the region's historical events.     

Anesthesia and acoustic stress-induced intra-uterine growth retardation in mice

Stress interferes with reproduction, adversely influencing implantation and fetal growth, and sometimes even leading to abortion. Here, we attempted to evaluate the early gestational effects of uncomfortable sound on pregnant mice and their offspring. Ten-week-old pregnant Jcl:ICR mice were exposed to sound (100 dB, random frequency between 9-34 kHz) for 8 hours on the 3(rd), 5(th) and 7(th) gestational days (GD). The effects of general anesthesia were also investigated, with or without acoustic stress. All groups were examined on the 18(th) GD for fetal growth. Fetal weight, number of ossified sacrococcygeal vertebrae and placental weight were all significantly reduced (P<0.0001) when stress was induced on the 7(th) GD, but not on the 3(rd) or 5(th) GD. This intra-uterine growth retardation (IUGR) was significantly inhibited by general anesthesia (P<0.0001), although general anesthesia alone induced significant IUGR (P<0.0001) when compared with control mice. This suggests that acoustic exposure indirectly exerts an effect on fetal growth, possibly via a psycho-maternal pathway. We also found that analysis of the number of ossified sacrococcygeal vertebrae is the most sensitive tool for the study of IUGR.     

Characteristics in Concentration of Chemical Species in Ambient Air Based on Three-Year Monitoring by Filter Pack Method

Continuous monitoring of concentrations of particulate matter and gaseous compounds for three years by a four-stage filter-pack method clarified the characteristics in the concentrations of chemical species in particulate matter and gaseous compounds in ambient air in Kobe, Japan. The amount of materials in blank filters was low enough for this method to be used for the monitoring of ambient air. Little or none of the hydrogen chloride was derived anthropogenically. The concentrations of both particulate sulfate and sulfur dioxide in spring and summer were significantly higher than those in autumn and winter. The concentration of gaseous nitric acid was high in summer, which suggests that active photochemical reactions in the atmosphere provided more nitrogen species in summer. The measured concentration products [HNO₃][NH₃] showed good agreement with the theoretical predictions with some exceptions. The total concentration of ammonium species showed no significant seasonal variation except that the concentration in winter was low. The concentration of nss-Ca²⁺ in spring was significantly higher than that in the other seasons, which is most likely associated with the so-called yellow-sand events. The concentrations of nss-K⁺ and nss-Ca²⁺ accounted for most of K⁺ and Ca²⁺, respectively, whereas that of nss-Mg²⁺ accounted for only 5% of Mg²⁺