Characterization of Polystyrene in Methyl Ethyl Ketone by Small-Angle X-Ray Scattering

Molecular and thermodynamic properties of polystyrene in methyl ethyl ketone were studied by a small-angle X-ray scattering with a Kratky camera. The molecular weight, radius of gyration, second virial coefficient, mass per unit length, hydrodynamic length, radius of gyration of cross section, persistence length, and radius of cross section were estimated. Some of these values were compared with the values determined by other methods. Both values agreed well each other

Time Delay Devices for Low-Speed Electronic Surge Analyser

In this paper, the authors introduce three kinds of time delay devices, which they have planned and developed extending over about the last ten years, to be applied to the low-speed surge analysers to analyse the surge performances on the transmission and distribution systems, which are composed of the time delay device and the low-speed electronic analog computer and can do away with the unavoidable defects of the conventional surge analysers. In addition, the authors simply illustrate the working principles of their surge analyser with examples of the single-conductor systems

Assessing the internal structure of landslide dams subject to possible piping erosion by means of microtremor chain array and self-potential surveys

An integrated geophysical approach comprising microtremor chain array and self-potential surveys was used to assess the internal structure of landslide dams subject to possible piping erosion in selected sites in Japan and Kyrgyzstan. The non-invasive geophysical approach is cost effective, environmentally friendly and portable, and hence, it has proven to be valuable for the geotechnical assessment of landslide dams where piping can trigger failure of the dam. While the microtremor chain array survey results revealed the internal structure of the landslide dam, the self-potential survey results indicated the path of anomalous seepage zones. In the surveyed sites of long-existing landslide dams, the presence of a seepage path in the dam was confirmed by a good correlation between the areas of low phase velocity and large negative self-potential anomalies. In summary, this integrated geophysical approach could be useful for the early risk assessment of landslide dams and prediction of landslide dam failure by piping

Leukemia autopsies in Japan

For the purpose to know whether the annual increase of leukemia incidence in Japan is due to some leukemogenic factors or due to the increased detection rate, the authors made some statistical survey of autopsy cases in which the diagnosis is reliable and not any type of leukemias escape the detection. The results showed that acute leukemias, which are found mostly in younger age, is actually increasing. In addition, it has been deduced that among the suspected factors the increase in ionizing radiation will be one of the most probable factors for the increase in leukemia incidence</p

Proteomics-based safety evaluation of multi-walled carbon nanotubes

This study evaluated the biological responses to multi-walled carbon nanotubes (MWCNTs). Human monoblastic leukemia cells (U937) were exposed to As-grown MWCNTs and MWCNTs that were thermally treated at 1800 degrees C (HTT1800) and 2800 degrees C (HTT2800). Cell proliferation was highly inhibited by As-grown but not HTT2800. However, both As-grown and HTT1800, which include some impurities, were cytotoxic. Proteomics analysis of MWCNT-exposed cells revealed 37 protein spots on 2-dimensional electrophoresis gels that significantly changed (p<0.05) after exposure to HTT1800 with a little iron and 20 spots that changed after exposure to HTT2800. Peptide mass fingerprinting identified 45 proteins that included heat shock protein beta-1, neutral alpha-glucosidase AB, and DNA mismatch repair protein Msh2. These altered proteins play roles in metabolism, biosynthesis, response to stress, and cell differentiation. Although HTT2800 did not inhibit cell proliferation or cause cytotoxicity in vitro, some proteins related to the response to stress were changed. Moreover, DJ-1 protein, which is a biomarker of Parkinson's disease and is related to cancer, was identified after exposure to both MWCNTs. These results show that the cytotoxicity of MWCNTs depends on their impurities, such as iron, while MWCNTs themselves cause some biological responses directly and/or indirectly in vitro. Our proteomics-based approach for detecting biological responses to nanomaterials is a promising new method for detailed safety evaluations.ArticleToxicology and Applied Pharmacology. 242(3):256-262 (2010)journal articl

Molecular Typing of Vibrio cholerae O1 Isolates from Thailand by Pulsed-field Gel Electrophoresis

The aim of the present study was to genotypically characterize Vibrio cholerae strains isolated from cholera patients in various provinces of Thailand. Two hundred and forty V. cholerae O1 strains, isolated from patients with cholera during two outbreaks, i.e. March 1999–April 2000 and December 2001–February 2002, in Thailand, were genotypically characterized by NotI digestion and pulsed-field gel electrophoresis (PFGE). In total, 17 PFGE banding patterns were found and grouped into four Dice-coefficient clusters (PF-I to PF-IV). The patterns of V. cholerae O1, El Tor reference strains from Australia, Peru, Romania, and the United States were different from the patterns of reference isolates from Asian countries, such as Bangladesh, India, and Thailand, indicating a close genetic relationship or clonal origin of the isolates in the same geographical region. The Asian reference strains, regardless of their biotypes and serogroups (classical O1, El Tor O1, O139, or O151), showed a genetic resemblance, but had different patterns from the strains collected during the two outbreaks in Thailand. Of 200 Ogawa strains collected during the first outbreak in Thailand, two patterns (clones)—PF-I and PF-II—predominated, while other isolates caused sporadic cases and were grouped together as pattern PF-III. PF-II also predominated during the second outbreak, but none of the 40 isolates (39 Inaba and 1 Ogawa) of the second outbreak had the pattern PF-I; a minority showed a new pattern—PF-IV, and others caused single cases, but were not groupable. In summary, this study documented the sustained appearance of the pathogenic V. cholerae O1 clone PF-II, the disappearance of clones PF-I and PF-III, and the emergence of new pathogenic clones during the two outbreaks of cholera. Data of the study on molecular characteristics of indigenous V. cholerae clinical isolates have public-health implications, not only for epidemic tracing of existing strains but also for the recognition of strains with new genotypes that may emerge in the future