Accumulation of radiocesium in wild mushrooms collected from a Japanese forest and cesium uptake by microorganisms isolated from the mushroom-growing soils

Mushrooms and soils samples collected from a sub-alpine forest of Mt. Fuji in Japan were measured for 137Cs and stable Cs. The ranges of 137Cs specific activities and stable Cs concentrations in the mushrooms were 291-7950 Bq kg(-1) dry weight and 4.69-58.1 mg kg(-1) dry weight, respectively. Both 137Cs specific activities and stable Cs concentrations in the mushrooms were higher than those in common agricultural plants. The 137Cs specific activities and stable Cs concentrations in the soils were 3.18-149 Bq kg(-1) dry weight and 0.618-2.18 mg kg(-1) dry weight, respectively. The appearance frequencies of filamentous actinomycetes and planktonic bacteria from the soils decreased according to increasing Cs contents in the medium. No relationship was observed between the appearance frequencies of those and the stable Cs concentrations in the soils. The filamentous actinomycetes from any soil sample could not grow in the presence of 25 mM Cs, although the planktonic bacteria from the soil samples could grow with up to 50 mM Cs in YM agar. In addition, the planktonic bacteria from approximately 70% of the soil samples could grow even in the presence of 100 mM Cs. Filamentous actinomycetes were more sensitive to Cs than planktonic bacteria. In in vitro experiments, Cs uptake by these strains of filamentous actinomycetes and planktonic bacteria was high in the presence of 5 mM CsCl and the strains accumulated Cs, the same as in mushrooms. Our results indicate that filamentous actinomycetes in the soils have higher sensitivity to Cs than planktonic bacteria, and several strains of filamentous actinomycetes have a high Cs accumulation in the presence of 5 mM Cs.     

Effects of difructose anhydride III (DFA III) administration on bile acids and growth of DFA III-assimilating bacterium Ruminococcus productus on rat intestine

The growth of DFA III-assimilating bacteria in the intestines of rats fed 3% DFA III for 2 weeks was examined. Sixty-four percent of the DFA III intake had been assimilated on day 3 of ingestion, and almost all of the DFA III was assimilated at the end of the experiment. The DFA III-assimilating bacterium, Ruminococcus productus, in DFA III-fed rats was in the stationary state of 10(8)-10(9) cells/g dry feces within a week from 10(6) cells/g dry feces on day 1 of DFA III ingestion. The number of R. productus cells was associated with the amount of DFA III excreted in the feces. The acetic acid produced from DFA III by R. productus lowered the cecal pH to 5.8. In control-fed rats and DFA III-fed rats, 94% of secondary bile acids and 94% of primary bile acids, respectively, were accounted for in the total bile acids analyzed. DFA III ingestion increased the ratio of primary bile acids and changed the composition of fecal bile acids. In conclusion, R. productus assimilated DFA III, produced short chain fatty acids, and the cecal pH was lowered. The acidification of rat intestine perhaps inhibited secondary bile acid formation and decreased the ratio of secondary bile acids. Therefore, it is expected that DFA III may prevent colorectal cancer and be a new prebiotic candidate.     

Phase-shifting interferometry with equal phase steps by use of a frequency-tunable diode laser and a Fabry-Perot cavity

A phase-shifting interferometry (PSI) with equal phase steps by use of a frequency-tunable diode laser and a Fabry-Perot cavity is proposed for the Carré algorithm. The measurement accuracy of the Carré algorithm depends on the equality of the phase steps. Using the Fabry-Perot cavity as a highly stable optical frequency reference, a high degree of phase step equality can be realized in PSI with an optical frequency shift. Our experimental scheme realizes an optical frequency step equality higher than 5.1 x 10(-5) and a measurement repeatability of lambda/800.     

Determination of the diffusion coefficients of NiCl2, ZnCl2, and CdCl2 in aqueous solution

The diffusion coefficients of NiCl₂, ZnCl₂, and CdCl₂ in the aqueous solution systems of MC1₂ and MC1₂-HC1 were measured at 298 K using a diaphragm-cell method. The data are listed as a function of molar concentrations of MC1₂ at the HC1 concentrations of 0, 0.1, 0.5, 1.0, and 2.0 mol dm^-3. It was found that the concentration dependencies of the diffusion coefficients for these metal chlorides in single-electrolyte solutions differed from each other. This could be explained in terms of changes in the mean activity coefficients of chloride and in the viscosities of those solutions. The diffusion coefficient of metal chloride in MC1₂-HC1 solution was greatly affected by the HC1 concentration; however, the behavior of the diffusion coefficients varied, depending on the kind of chloride involved. In NiCl₂-HCl solutions, an increase in HC1 con-centration caused a decrease in the diffusion coefficient value, while in ZnCl₂-HCl solutions, the addition of 2 mol dm^-3 HC1 caused an increase in the diffusion coefficient of ZnCl₂. These phenomena are quite different from those of the sulfate systems reported in our previous work. It was also demonstrated that the concentration dependency of the diffusion coefficients of MC1₂ in aqueous MC1₂-HC1 solutions could be attributed to the diffusion potential as well as the changes in the mean activity coefficient and viscosity. Masami Aoki, formerly Graduate Student, Department of Met-allurgy, Kyoto University.     

Formation and reactions of isocyanic acid during the catalytic reduction of nitrogen oxides

Reactions which can produce and consume isocyanic acid (HNCO) over two types of catalysts active for the reduction of nitrogen oxides have been investigated. More than 1000 ppm HNCO can be produced by the reduction of 3000 ppm NO with H₂/CO mixtures over a Pt/SiO₂ catalyst. Complete hydrolysis of HNCO to ammonia and carbon dioxide occurs if even weakly catalytic materials, such as CeO₂/SiO₂ and BaO/SiO₂, are placed downstream. Isocyanic acid is also involved as an intermediate in the reaction of nitromethane over CoZSM5 and CuZSM5 under the conditions of hydrocarbon SCR. In the initial stages of reaction there is complete conversion through to N₂ with CuZSM5 but the process stops at ammonia with CoZSM5 at temperatures below 350°C. In both cases, but especially with CoZSM5, isocyanic acid becomes observable as the catalyst deactivates during continuous exposure at temperatures below about 290°C. In situ FTIR measurements indicate that deactivation is due to a reaction between isocyanic acid and ammonia which generates cyclic striazine compounds.     

Dynamic Observation of Crack Propagation in Piezoelectric Multilayer Actuators

Crack propagation in multilayer piezoelectric actuators made of Pb((Ni_1/3Nb_2/3), Ti, Zr)O₃ ceramics with an interdigital electrode configuration was observed dynamically under an applied cyclic electric field using charge coupled device microscopy. The crack was observed only under a high electric field, and it healed under zero field. The crack was initiated at the internal electrode edge and propagated from the electrode edge in three directions. The electric-field-induced displacement was measured simultaneously with the propagation. The displacement of the multilayer actuator became gradually smaller and asymmetric with respect to the sign of the field with increased driving cycle.     

Vis-NIR Hyperspectral and Terahertz Imaging Investigations on a Fresco Painting on “Tavella” by Alessandro Gherardini

In this paper, we report on Vis-IR hyperspectral and terahertz imaging investigations carried out on a fresco painting on tavella depicting St. John Baptist, by Alessandro Gherardini (1655–1726). Measurements took place at the Restoration Laboratories of the former “Polo Museale della Toscana,” in Florence, in the framework of the Italy-Japan collaborative project THz-ARTE. We show how the hyperspectral data made it possible to determine the state-of-conservation of Gherardini’s painting, while reflection imaging measurements performed at 97 GHz provided a qualitative evaluation of the position of defects inside the tavella.     

Inspection of Asian Lacquer Substructures by Terahertz Time-Domain Imaging (THz-TDI)

Lacquering is considered one of the most representative Asian artistic techniques. While the decorative part of lacquerwares is the lacquer itself, their substructures serve as the backbone of the object itself. Very little is known about these hidden substructures. Since lacquerwares are mostly composed of organic materials, such as urushi, wood, carbon black, and fabrics which are very X-ray transparent, standard X-ray radiography has some problems in achieving clear X-ray radiographic images. Therefore, we wanted to contribute to the understanding of the lacquer manufacturing technique by inspecting the substructures of Asian lacquerwares by means of THz time-domain imaging (THz-TDI). Three different kinds of Asian lacquerwares were examined by THz-TDI, and the outcomes have been compared with those obtained by standard X-radiography. THz-TDI provides unique information on lacquerwares substructures, aiding in the comprehension of the manufacturing technology yielding to these precious artefacts.     

The E3 Ubiquitin-Protein Ligase RNF4 Promotes TNF-α-Induced Cell Death Triggered by RIPK1

Receptor-interacting protein kinase 1 (RIPK1) is a key component of the tumor necrosis factor (TNF) receptor signaling complex that regulates both pro- and anti-apoptotic signaling. The reciprocal functions of RIPK1 in TNF signaling are determined by the state of the posttranslational modifications (PTMs) of RIPK1. However, the underlying mechanisms associated with the PTMs of RIPK1 are unclear. In this study, we found that RING finger protein 4 (RNF4), a RING finger E3 ubiquitin ligase, is required for the RIPK1 autophosphorylation and subsequent cell death. It has been reported that RNF4 negatively regulates TNF-α-induced activation of the nuclear factor-κB (NF-κB) through downregulation of transforming growth factor β-activated kinase 1 (TAK1) activity, indicating the possibility that RNF4-mediated TAK1 suppression results in enhanced sensitivity to cell death. However, interestingly, RNF4 was needed to induce RIPK1-mediated cell death even in the absence of TAK1, suggesting that RNF4 can promote RIPK1-mediated cell death without suppressing the TAK1 activity. Thus, these observations reveal the existence of a novel mechanism whereby RNF4 promotes the autophosphorylation of RIPK1, which provides a novel insight into the molecular basis for the PTMs of RIPK1.