Evaluation of 4-nonylphenols and 4-tert-octylphenol contamination of fish in rivers by laboratory accumulation and excretion experiments

Laboratory accumulation and excretion experiments of 4-nonylphenols (NP) and 4-tert-octylphenol (OP) were performed for killifish (Oryzias latipes). The bioconcentration factors (BCF, wet weight) in the whole fish were mean +/- SD of 167 +/- 23 (n = 4) for NP and 261 +/- 62 (n = 4) for OP. The biological half-lives in the whole fish were 9.9 h for NP and 7.7 h for OP. Parallel to the laboratory experiments, field survey on the chemicals contamination for water and ayu fish (Plecoglossus altivelis) from rivers flowing into Lake Biwa was performed. The contamination was not so high in agreement with the laboratory experimental data and the field BCF values (wet weight) in the ayu fish were 21 +/- 15 (n = 8) for NP and 297 +/- 194 (n = 3) for OP.     

Acute non-cancer mortality excess after polychlorinated biphenyls and polychlorinated dibenzofurans mixed exposure from contaminated rice oil: Yusho

In Japan in 1968, rice-oil contaminated by polychlorinated biphenyls and polychlorinated dibenzofurans caused severe food poisoning, termed “Yusho” (oil disease). Several previous studies attempted to evaluate the effects targeting officially-certified Yusho patients. However, these studies have several limitations such as the left-truncated nature of the registry or residual confounding arising from the referent population selection. We thus conducted an area-based standardized mortality ratios (SMRs) study using vital statistics. A severely affected area (Tamanoura area) was adopted as the exposure group, with a reference population from Nagasaki prefecture in Kyushu, which included the Tamanoura. A large number of residents in Tamanoura were exposed to the rice-oil (28% of all the certified cases as of 2009). We estimated SMRs of non-cancer and cancer diseases for the years 1968-2002. Shortly after the exposure, SMRs of all causes, diabetes mellitus, cardiovascular disease, pneumonia/bronchitis, and bronchus/lung cancer were elevated. In particular, SMRs of heart disease were 1.97 [95% confidence intervals (CI): 1.09-3.56] in 1968, 2.05 (95% CI: 1.16-3.60) in 1969, and 1.89 (95% CI: 1.05-3.41) in 1975. However, we did not observe clear increase in SMRs more than 10 years after the exposure. This study provides further evidence in Yusho, especially on acute effects on non-cancer mortality.     

In situ Raman study on single- and double-walled carbon nanotubes as a function of lithium insertion

We investigated the electrochemical lithium ion (Li(+)) insertion/desertion behavior on highly pure and bundled single- and double-walled carbon nanotubes (SWNTs and DWNTs) using an in situ Raman technique. In general, two storage sites could host Li(+) in SWNT and DWNT bundles when varying an external potential: a) the outer surface sites, and b) the interstitial spaces within the bundles. The most sensitive changes in the tangential mode (TM) of the Raman spectra upon doping with Li(+) can be divided into two regions. The first region was found from 2.8 to 1.0 V (the coverage of Li(+) on the outer surface of a bundled nanotube) and was characterized by the loss of resonant conditions via partial charge transfer, where the G(+) line of the SWNT and the TM of the outer tube of DWNTs experienced a highly depressed intensity, but remained almost constant in frequency. The appearance of a Breit-Wigner-Fano (BWF) profile provided strong evidence of metallic inner tubes within DWNTs. The second region was observed when the applied potentials ranged from 0.9 to 0 V and was characterized by Li(+) diffusion into the interstitial sites of the bundled nanotube material. This phenomenon invoked a large downshift of the G(-) band in SWNTs, and a small downshift of the TM of the inner tube of DWNTs caused by expansion of the C--C bonds due to the charge transferred to the nanotubes, and the disappearance of the BWF profile through the screening effect of the interstitial Li(+) layers.     

FTIR studies of adsorption and photocatalytic decomposition under UV irradiation of dimethyl sulfide on calcium hydroxyapatite

The adsorption and photocatalytic decomposition under UV irradiation of dimethyl sulfide ((CH₃)₂S: DMS) on synthetic colloidal calcium hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂: Hap) particles were examined by in vacuo IR measurements. The adsorption isotherms of DMS on Hap exhibited the Langmuir type. The saturated adsorbed amount of DMS was increased with increasing the outgassing temperature of Hap, showing a maximum of 2.4 molecules/nm² at 250 °C. Similar tendency could be observed for change in area intensity of surface P-OH bands of Hap estimated from in vacuo IR measurements against outgassing temperature. By adsorption of DMS, the surface P-OH bands of Hap weakened while the CH bands due to DMS appeared. These results revealed that the DMS was adsorbed on surface P-OH groups of Hap. When the UV light was irradiated to the DMS-adsorbed Hap, the surface P-OH bands revived and the CH bands weakened. This fact strongly indicated the photocatalytic decomposition of DMS took place on surface P-OH groups of Hap, which was thought to be due to the formation of surface P-OH radicals by UV irradiation.     

Single-molecule conductance of π-conjugated rotaxane: new method for measuring stipulated electric conductance of π-conjugated molecular wire using STM break junction

An electronic conductance with small fluctuations, which is stipulated in single-molecule junctions, is necessary for the precise control of single-molecule devices. However, the suppression of conductance fluctuations in conventional molecular junctions is intrinsically difficult because the fluctuations are related to the contact fluctuations and molecular motion. In the present study involving experimental and theoretical investigations, it is found that covering a single π-conjugated wire with an α-cyclodextrin molecule is a promising technique for suppressing conductance fluctuations. The conductance histogram of the covered molecular junction measured with the scanning tunneling microscope break-junction technique shows that the conductance peak for the covered junction is sharper than that of the uncovered junction. The covering technique thus has two prominent effects: the suppression of intramolecular motion, and the elimination of intermolecular interactions. Theoretical calculations of electronic conductance clearly support these experimental observations.     

Development of a grout database for geological disposal of high-level radioactive waste

Japan Atomic Energy Agency (JAEA) has developed a grout database (GDB) comprising the latest technical data of grout materials relevant to the geological disposal of high-level radioactive waste (HLW). Currently, only newly developed grout materials of low pH cements, superfine spherical silica and colloidal silica, which are expected to provide a target pH ≤ 11 leachate, are included in the GDB. Case examples from on-site works and laboratory-based tests that have been published in the literature have been used to add construction and material details to the GDB. The GDB is available online (https://groutdb.jaea.go.jp/grout/ [in Japanese]) for registered users to obtain and provide data of grout technology. Furthermore, the GDB can be used to correlate requirements of mechanical, physical, and/or chemical properties of a grout material to specifically address concerns over safety assessment, material and injection method development, and/or prediction of grout penetration.     

Microstructural evolution and mechanical property in dual two-phase intermetallic alloys composed of geometrically close-packed Ni3 X (X: Al and V) containing Nb

Dual two-phase intermetallic alloys composed of geometrically close-packed (GCP) structures of Ni₃Al (L1₂) and Ni₃V (D0₂₂) containing Nb were investigated in terms of microstructural evolution during low-temperature annealing (aging) and the related mechanical properties. The eutectoid region, i.e. the prior Al phase (Ni solid solution) is composed of the lamellar-like structure consisting of Ni₃Al (L1₂) and Ni₃V (D0₂₂) even at an early aging stage, and then coarsen with increasing aging time. The lamellar-like structure tend to align along direction and on {001} plane in the prior A1 phase (or the L1₂ phase). In a wide range of temperature, the dual two-phase intermetallic alloys showed high yield and tensile strength, and also reasonable tensile ductility, accompanied with ductile fracture mode. The observed mechanical properties were less sensitive to the microstructural evolution during low-temperature annealing (aging), meaning that the present dual two-phase intermetallic alloy is promising for a new type of high-temperature structural material.     

Effects of annual fluctuation of environmental factors on starch properties in potato tuber development

To test the effects of the annual fluctuation of the environmental factors on the starch properties in potato tuber development, starches were isolated from potato cultivars grown for ten consecutive years (2001–2010) on the experimental farm in Memuro, Hokkaido, the northernmost island of Japan. The median granule size, phosphorus content, and rapid visco‐analyzer pasting properties, peak viscosity, breakdown, and pasting temperature of these starches were analyzed. Daily temperature and precipitation records in Memuro were obtained from the Japan Meteorological Agency. Moreover, the correlation coefficients of yearly accumulated temperature and precipitation from flowering to harvesting with all the starch quality parameters were calculated. No relationships of accumulated temperature with median granule size, peak viscosity, and breakdown were found. The low phosphorus content was slightly associated with the high accumulated temperature. The pasting temperature was significantly and positively correlated with the accumulated temperature, suggesting that the pasting temperature strongly responds to the environmental temperature during potato tuber development. In contrast, all the starch quality parameters were almost irrespective of the precipitation during potato tuber development.     

SEM observation of wet biological specimens pretreated with room-temperature ionic liquid

A facile pretreatment process for SEM: The use of room temperature ionic liquids (RTILs) provides an interesting method for SEM of biological specimens. We used a novel and concise method of pretreatment, excluding fixation or Au sputtering steps. Fine and smooth-textured SEM images of a wide variety of biological specimens treated in this way were observed without artefacts.