COMPARISON OF PAHS,NITRO-PAHS AND OXY-PAHS ASSOCIATED WITH AIRBORNE PARTICULATE MATTER AT ROADSIDE AND URBAN BACKGROUND SITES IN DOWNTOWN TOKYO,JAPAN

Atmospheric polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and oxy-PAHs are emitted from primary sources. Some nitro-PAHs and oxy-PAHs can also arise from secondary formation in the atmosphere. To assess the relative importance of these sources, the polycyclic aromatic compound (PAC) concentrations were determined at a roadside (Roadside site) and on a rooftop (Urban Background site) in downtown Tokyo Japan. The concentrations of PAHs, 1-nitropyrene and oxy-PAHs at the Roadside site were higher than those at the Urban Background site, while 2-nitrofluoranthene levels were the same at both sites. However, the mean ratios of concentrations at the Urban Background site to the Roadside site were in the order 1,8-naphthalic anhydride>9,10-anthraquinone>PAHs or 1-nitropyrene or acenaphthenequinone or benzanthrone. This suggests that in addition to vehicle emissions, a considerable fraction of some of the oxy-PAHs studied originates from another source, which might be secondary formation by atmospheric PAH degradation, and this contribution varied among the oxy-PAHs.     

Absolute quantitation of quercetin and the glycosides in natural food additives by quantitative NMR

We are developing a simple absolute quantitation method for organic compounds, by means of quantitative nuclear magnetic resonance (qNMR), with traceability to the International System of Units (SI units). The qNMR method was applied to the absolute quantitation of rutin, isoquercitrin and quercetin in natural food additives, rutin (extract), enzymatically decomposed rutin extract and quercetin, and those compounds as commercial reagents. In this study, 1,4-bis-(trimethylsilyl)benzene-d(4) (1,4-BTMSB-d(4)) whose purity was precisely evaluated on the basis of metrology, was newly used as a qNMR reference material, to be added to the sample solution as an internal standard. The contents of quercetin and quercetin glycosides were calculated from the ratio of the signal intensities of each aromatic proton at the 2' position of the three compounds (these are observed at different chemical shifts) to the eighteen protons of the six methyl groups on 1,4-BTMSB-d(4) used as a qNMR reference material. Rapid and simple qNMR method with only one step process was carried by using 1,4-BTMSB-d(4). It was demonstrated that the purities of rutin, isoquercitrin and quercetin can be separately determined by qNMR without the need for a separation process or reference materials for all the target compounds.     

Translation among CNFs, characteristic models and ordered binary decision diagrams

We consider translation among conjunctive normal forms (CNFs), characteristic models, and ordered binary decision diagrams (OBDDs) of Boolean functions. It is shown in this paper that Horn OBDDs can be translated into their Horn CNFs in polynomial time. As for the opposite direction, the problem can be solved in polynomial time if the ordering of variables in the resulting OBDD is specified as an input. In case that such ordering is not specified and the resulting OBDD must be of minimum size, its decision version becomes NP-complete. Similar results are also obtained for the translation in both directions between characteristic models and OBDDs. We emphasize here that the above results hold on any class of functions having a basis of polynomial size.     

Solar cell efficiency tables (version 12)

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since January 1998 are briefly described. © 1998 John Wiley & Sons, Ltd.     

Application of land use regression to regulatory air quality data in Japan

A land use regression (LUR) model has been used successfully for predicting traffic-related pollutants, although its application has been limited to Europe and North America. Therefore, we modeled traffic-related pollutants by LUR then examined whether LUR models could be constructed using a regulatory monitoring network in Shizuoka, Japan. We used the annual-mean nitrogen dioxide (NO₂) and suspended particulate matter (SPM) concentrations between April 2000 and March 2006 in the study area. SPM accounts for particulate matter with an aerodynamic diameter less than 8 μm (PM₈). Geographic variables that are considered to predict traffic-related pollutants were classified into four groups: road type, traffic intensity, land use, and physical component. Using geographical variables, we then constructed a model to predict the monitored levels of NO₂ and SPM. The mean concentrations of NO₂ and SPM were 35.75 μg/m³ (standard deviation of 11.28) and 28.67 μg/m³ (standard deviation of 4.73), respectively. The final regression model for the NO₂ concentration included five independent variables. R² for the NO₂ model was 0.54. On the other hand, the regression model for the SPM concentration included only one independent variable. R² for the SPM model was quite low (R² = 0.11). The present study showed that even if we used regulatory monitoring air quality data, we could estimate NO₂ moderately well. This result could encourage the wide use of LUR models in Asian countries.     

Crack propagation life prediction of a perforated plate under thermal fatigue

Superheater outlet headers of boilers are well known to be subjected to the cycling of high pressure and high thermal stress during plant operations. Thermal stresses during cyclic operation are generally severest on the inside surface of the ligaments between the stub-tube holes, where many examples of ligament cracking due to thermal fatigue have been found recently. A method to predict the crack propagation life of the ligaments of boiler headers under thermal fatigue has been required. Firstly in this paper, to model the crack propagation behavior of the ligament regions of boiler headers, a perforated plate of normalized and tempered 2 1/4Cr–1Mo steel was examined under out-of-phase thermal fatigue at a maximum temperature of 600°C in the air. Inelastic analysis of the perforated plate under thermal fatigue was carried out, and the nonlinear fracture mechanics parameters such as the J and C^* integral were obtained by the line integral for observed cracks. A simplified method was proposed for predicting these parameters under displacement-controlled conditions such as thermal fatigue. In this method, the change of the macroscopic stress–strain relation of the perforated plate with propagating cracks was combined with the reference stress concept under displacement-controlled conditions. The predicted fracture mechanics parameters from this method coincided well with those from the inelastic analysis. The prediction of the crack propagation life on the basis of the proposed method provided a good correspondence with the test results of the perforated plate under thermal fatigue.     

Reaction Kinetics of Methanol Carbonylation to Methyl Formate Catalyzed by CH3O− Exchange Resin

The carbonylation of methanol with CO using CH₃O⁻ exchange resin as a heterogeneous catalyst at temperatures near 350 K is examined systematically in an attempt to derive kinetic rate expressions for the reaction. The activation energies for the carbonylation and decarbonylation reactions are found to be 68 kJ/mol and 105 kJ/mol, respectively. The CH₃O⁻ exchange resin is also shown to suffer no degradation of catalytic activity upon repeated separation and re-use at 353 K.     

Usefulness of hybrid capture HPV DNA assay as a diagnostic tool for human papillomavirus infection

The purpose of this study was to determine the usefulness of the hybrid capture HPV DNA assay, a new nonradioactive solution hybridization assay, as a diagnostic tool for human papillomavirus infection. In a total of 234 women, samples for the hybrid capture assay and polymerase chain reaction (PCR) assay were obtained by wiping a swab across the cervix and external os (either a Dacron swab or a cotton swab was used). The papanicolaou smear test (Pap smear) was carried out on all 234 women. Tissue samples for biopsy were obtained by colposcopy from 118 of the women. Fisher exact test was used for statistical analyses. Using the hybrid capture assay, HPV DNA of high- and intermediate-oncogenic-risk type was detected in 23 (13.9%) of 166 samples from women with Pap smear Class I or II, and 48 (70.6%) of 68 with Pap smear Class III, IV or V (p < 0.0001). The HPV DNA type was detected in 18 (29.0%) of 62 samples from those with no evidence of cervical intraepithelial neoplasia and 44 (78.6%) of 56 with cervical intraepithelial neoplasia or squamous cell carcinoma (p < 0.0001). Correlation of the test results between the hybrid capture test and PCR was determined by using the 217 samples in which both test results were available (PCR test results were not obtainable in 17 samples. When PCR is set as a gold standard, the hybrid capture test has high sensitivity (74.6%) and specificity (92.7%). These findings suggest that the hybrid capture HPV DNA assay is a useful method for diagnosing HPV infection in the clinic.     

Memory mechanism of printable ferroelectric TFT memory with tertiary structured polypeptide as a dielectric layer

Printable nonvolatile memory devices have been attracting considerable interest because of their application to flexible large-area devices. In order to fabricate such memory devices, it is necessary to discover a new ferroelectric material and to develop an efficient process for its preparation. We have previously reported that poly(γ-methyl-L-glutamate) (PMLG) functions as a ferroelectric layer of an organic thin-film transistor (OTFT) memory device [S. Uemura, A. Komukai, R. Sakaida, M. Yoshida, S. Hoshino, T. Kodzasa, T. Kamata, Synth. Met. 153 (2005) 405]. Further, ferroelectricity is observed when α-helical PMLG molecules are aligned in a direction parallel to the film surface. In this study, we investigate the effect of the tertiary structure of PMLG molecules on the hysteresis of OTFT memory devices, i.e., memory performance. From the results, we conclude that the hysteresis of the OTFT is strongly affected by the helical tertiary structure of PMLG molecules, similar to the structure of a cholesteric liquid crystal phase.