Ionic liquid monomers with ion pair interaction energies ranging from 73.0 to 101.4 kcal/mol were designed by using the calculated electrostatic potential (ESP) values of the component ions. The ionic liquid monomers were classified as cationic monomers with an anionic counterion and anionic monomers with a cationic counterion. We evaluated the calculated ion pair interaction energy using counterion mobility as an indicator. One component of the ion pair was fixed onto a dielectric elastomer by using alkoxysilane coupling agents, while the counterion remained free to move under the applied voltage. We then measured the relative dielectric constant at 0.01 Hz, which is an indicator of the mobility of the counterion. The results showed a good correlation between the calculated ion pair interaction energy and the relative dielectric constant. The lower the ion pair interaction energy is, the easier the dissociation of the ion pair. From this result, we were able to prove the correlation between the calculated ion pair interaction energy and the mobility of the counterion. Furthermore, classification of other ion pair compounds and polyelectrolyte polymer brushes that follow the anion Hofmeister series based on ion pair interaction energies revealed the correlation between physical properties and the ionic structure. Various ionic compounds with desired physical properties can be designed by using the calculated ion pair interaction energies.

FIA combustion chambers have been used broadly for the testing of the combustibility of various bunker fuel oils. Their ultimate goal is, of course, discriminating good fuels from trouble inducing fuels, but so far not very successfully. There is a lack of a quantitative evaluation method for the combustion process inside them. In this study, multivariate analysis was applied to the heat release curves. For the first time we can characterize the minute differences between the trouble inducing fuel and the normal one. As a result, with 10 variables, much more precise discrimination of good fuels was realized. The reliability high was 95%. However, this figure cannot be trusted fully owing to insufficient samples.

Experimental studies are conducted to clarify the relationship between the flow structure and the cutting capability of abrasive water injection jets (AWIJs). The water velocity is obtained by the PIV method. It is shown that the water velocity decreases steeply with slight addition of abrasive. When the abrasive flow rate is relatively large, the water velocity is 0.25 to 0.35 times fo the theoretical velocity calculated by Bernoulli's equation. Cutting tests conducted with specimens of aluminum plate show the existence of the optimum abrasive-mass flow rate, which gives minimum taper of the cut and narrow initial damage zone.

In Japan, the largest source of dioxin is solid waste incineration plants. Because workers employed at these plants handle fly ash and slag contaminated by dioxins, they can take dioxins into the body during work and their health may be adversely effected. This paper describes the dioxin exposure concentration, daily dioxin intake and blood dioxin level in workers employed at municipal incineration plants. The estimated dioxin exposure concentrations were 0.5 to 7.2 pg TEQ/m3 in the daily operation and 0.2 to 92,000 pg TEQ/m3 in the periodic maintenance. It was also expected that the daily dioxin intake can exceed the tolerable daily intake (TDI) in incineration plants with fly ash of high dioxin concentration. The mean of blood dioxin concentration was 346 pg TEQ/g lipid in the highest exposed worker group of the Toyono-gun incineration plant and those were 11 to 40 pg TEQ/ g lipid in the other incineration plants.

The aim of the present study is to clarify in situ expression of platelet-derived growth factor (PDGF) and its receptors in different phases of inflammatory bowel disease (IBD). Tissues samples were obtained from 20 patients with ulcerative colitis (UC) and 29 with Crohn's disease (CD) at surgery. In situ hybridization and immunohistochemistry on frozen sections were performed for PDGF-A and -B and its alpha and beta receptors (alphaR and betaR). The area of active inflammation was infiltrated by abundant polymorphonuclear and mononuclear leukocytes, of which the latter expressed mRNA and proteins of PDGF-A, -B, and -alphaR and mRNA for PDGF-betaR. The area of active fibrosis, characterized by activated fibroblasts/ myofibroblasts, was juxtaposed to ulceration, which is induced as a repair process to tissue destruction. In these areas, activated fibroblasts/myofibroblasts were positive for mRNA and protein of PDGF-A, -B, -alphaR, and -betaR. The expression of PDGF-A, -B, and -alphaR declined significantly in the scar area. Our results suggest that PDGF is not only important as an inducer of fibrosis in the repair phase but also it is involved in the active inflammatory phase possibly as a chemoattractant for mononuclear inflammatory cells.

Estimation of Dioxin Exposure Concentrations and Dioxin Intakes of Workers at Continuously Burning Municipal Waste Incinerators: Shinji Kumagai, et al. Department of Occupational Health, Osaka Prefectural Institute of Public Health—In order to examine the dioxin exposure level in incinerator workers, total dust concentration in the breathing zone and dioxin concentrations in fly ash, slag and deposited dust were determined at three municipal waste incineration plants A, B and C equipped with continuously burning incinerators of stoker type. Three incinerators were operated at plants A and B, and four at plant C. The incinerators of plants A and B were equipped with electrostatic precipitators for removing particulate matter from the flue gas stream. In plant C, three incinerators were equipped with electrostatic precipitators and one with a bag filter. Total dust exposure concentrations during daily operation of the incinerators were 0.11 to 1.50 mg/m3, and dioxin concentrations in the deposited dust were 1.0 to 6.4 ng toxicity equivalent (TEQ)/g. Dioxin exposure concentrations were estimated to be 0.5 to 7.1 pg TEQ/ m3. Total dust exposure concentrations during periodic cleaning of the inside of the incinerator were 30 to 780 mg/m3, and dioxin concentrations in the slag were 0.004 to 1.1 ng TEQ/g. Dioxin exposure concentrations were estimated to be 0.5 to 48 pg TEQ/m3. Total dust exposure concentrations during periodic cleaning of the inside of the electrostatic precipirator were 51 to 2,000 mg/m3, and dioxin concentrations in the fly ash were 7.3 to 64 ng TEQ/g. Dioxin exposure concentrations were estimated to be 370 to 92,000 pg TEQ/m3, which were 150 to 37,000 times as high as the dioxin administrative level (2.5 pg TEQ/m3). Total of occupational and environmental dioxin intakes for an incinerator worker is predicted to exceed the tolerable daily intake (TDI: 4 pg TEQ/kg/d), when dioxin concentration in fly ash is 1,000 ng TEQ/g, even if an airline mask is used during the periodic maintenance. Consequently, it is essential to decrease the dioxin concentration in fly ash. When the dioxin concentration in fly ash is no higher than 100 ng TEQ/g, if an airline mask is used during the periodic maintenance, the dioxin intake is predicted to be lower than the TDI. Thus, wearing an airline mask would be effective.

Objectives: To find whether or not incinerator workers employed at intermittently burning municipal incineration plants are exposed to high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Methods: 20 Workers employed at three municipal waste incineration plants (incinerator workers) and 20 controls were studied. The previous job, dietary, smoking, and body weight and height were obtained from a questionnaire survey. Concentrations of PCDDs and PCDFs were measured in serum samples of the workers and the deposited dust of the plants. The influence of occupational exposure on concentrations of PCDDs and PCDFs in serum samples was examined by multiple regression analysis. Results: Dust analysis showed that dominant constituents were octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) among the PCDDs, and 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) among the PCDFs. The toxicity equivalents (TEQs) of summed PCDDs and PCDFs in the deposited dust were 0.91, 33, and 11 ng TEQ/g, respectively, for plants I, II, and III. The means of TEQ in serum samples of summed PCDDs and PCDFs in the incinerator workers and controls were 22.8 and 16.4 pg TEQ/g lipid for area I, 29.4 and 19.3 pg TEQ/g lipid for area II, and 22.8 and 24.9 pg TEQ/g lipid for area III, which were almost the same as for the general population of Japan. No significant differences in the TEQ of PCDDs and TEQ of PCDDs and PCDDs were found between the incinerator workers and the controls. However, the TEQ of PCDFs was significantly higher among the incinerator workers in areas I and II, and the 1,2,3,4,6,7,8-HpCDF concentration was also significantly higher for all three areas. When the occupational exposure index for each constituent of PCDDs and PCDFs was defined as the product of the duration of employment at the incineration plant and the concentration of the constituent in the deposited dust, multiple regression analysis showed that the concentrations of HxCDF, HpCDF, and TEQ of PCDFs in serum samples increased with the occupational exposure index. The multiple regression analysis also suggested that significant factors affecting the concentrations in serum samples were area for HxCDD, age for TCDD, PeCDD, PeCDF, TEQ of PCDDs, TEQ of PCDFs, and TEQ of summed PCDDs and PCDFs, and BMI for HxCDD, HpCDD, and OCDD. Conclusion: This study showed that incinerator workers employed at intermittently burning incineration plants were not necessarily exposed to high concentrations of PCDDs and PCDFs. However, the increases in the concentrations in serum of HxCDF, HpCDF and TEQ of PCDFs with the occupational exposure index suggest that the incinerator workers had inhaled dust containing PCDDs and PCDFs during their work.

A simple lung model (mucosal blood flow and metabolism model, MBM model) was developed to describe the uptake of organic solvents and investigate the role of mucosal blood flow and metabolism. The model separates the lung into four compartments, the peripheral bronchial tract (gas phase), the mucus layer lining the wall surface of the tract, the alveolar space (gas phase), and the alveolar blood. Solvent molecules are absorbed in the mucus layer during inhalation and released during exhalation. The deposited solvent diffuses radially into the mucosal tissue of the respiratory tract and transfers to the mucosal blood flow. To describe this behavior, a hypothetical mucosal blood flow throughout the mucus layer was used. The solvent in the mucosal tissue may be also metabolized, and a hypothetical metabolism in the mucus layer was used. The rate of the hypothetical mucosal blood flow was determined to be 5.2 ml/min based on the best fitting of previously obtained data for seven polar organic solvents. The MBM model predicts that as the blood-air partition coefficient (lambda(B)) increases from 0.1 to 20, the relative end-exhalation (E(end)) will decrease from 0.89 to 0.07, and as lambda(B) increases to 500, E(end) will increase to 0.33. After lambda(B) = 500, E(end) is predicted to decrease again, and at lambda(B) = 10000, E(end) is 0.09. The model also predicts that as lambda(B) increases from 0.1 to 10, the relative uptake (U) increases from 0.08 to 0.61, and as lambda(B) increases to 150, U decreases to 0.50. After lambda(B) = 150, U increases again, and at lambda(B) = 10,000, U is 0.8. The predictions show good agreement with values observed in human experimental studies. The MBM model predicts that uptake by the mucosal blood (U(Al)) would be equal to uptake by the alveolar blood (U(Mu)) at lambda(B) of 1000 and U(Al) is more than 90% of total uptake at lambda(B) > 10,000. The model also shows that U is significantly increased by the mucosal metabolism at lambda(B) between 50 and 5000. Especially, U in the case of CL(Mu) = 100 ml/min is higher by 0.3 than that in the nonmucosal metabolism.

Health Effects of Acute Exposures to Methyl Bromide during Soil Fumigation Inside Greenhouses: Shigeki Koda, et al. Department of Public Health, Kochi Medical School—In order to estimate exposure to methyl bromide (CH3Br) during soil fumigation inside greenhouses and examine health effects in agricultural workers, an interview survey, environmental monitoring and occupational exposure to CH3Br were conducted. An interview survey of working conditions and subjective symptoms related to exposure to CH3Br during soil fumigation was conducted on 241 agricultural workers between 1996 and 1998, and 225 agricultural workers were analyzed. The environmental monitoring during soil fumigation and occupational exposure to CH3Br were conducted in cooperation with eight agricultural workers. Finally, the authors examined the exposure levels to CH3Br after improving soil fumigation techniques. Many agricultural workers used a large amount of CH3Br in soil fumigation within a short time period without personal protective equipment. The odds ratio for nausea was significantly increased by fumigation with mulch. The odds ratios for irritation of the eyes, feeling sick, cough and anxieties about health were significantly increased by wearing gas masks. The odds ratios for forget fulness and ringing in the ears were significantly increased at ages over 50 yr. The concentrations of CH3Br in greenhouses were changed from 5,000 ppm to 1,100 ppm during soil fumigation, and occupational exposure was 57.2 ppm while opening the sheets of greenhouses and below ACGIH‐TLV (1 ppm) in CH3Br ejection, piping and planting. The agricultural workers could avoid exposure to high concentrations of CH3Br by improving in soil fumigation techniques. Soil fumigation inside greenhouses has occupational safety and health issues related to the large amounts of CH3Br used within short fumigation periods, the lack of precautions for handling chemicals, improper use of protective equipment and lack of training in safety practices resulting in agricultural workers being at risk of acute exposure to CH3Br.

In order to clarify the actual condition of occupational health management for hazardous and musculo-skeletally stressful work factors in small-scale enterprises (SSEs) in Japan, a questionnaire survey was conducted in an area near Osaka city. The hazardous work factors examined were dust, organic solvents, lead, specified chemical substances, anoxia, noise, hand-arm vibration, ionizing radiation, high and low temperatures, and high air pressure. The musculo-skeletally stressful work factors examined were VDT work, prolonged standing, unnatural postures, handling of heavy weights, and stress on neck, shoulders and arms. The number of SSEs that replied to the questionnaire was 765 (recovery rate: 69.3%). Enterprises with noise, dust, hand-arm vibration and organic solvents numbered 14.0%, 10.7%, 6.9% and 6.4%, respectively, and those with other hazardous factors numbered less than 3%. Special medical examinations and working environment measurements for hazardous factors were conducted in 0.0% to 26.7% and 0.0% to 13.3%, respectively, of the enterprises. Working environment controls were conducted in 0.0% to 40.2%. Enterprises with prolonged standing and VDT work, were 42.0% and 35.8%, whereas those with other stressful factors were approximately 30%. Special medical examinations for musculo-skeletally stressful factors were conducted in 3.0% to 5.1% of the enterprises, and work controls were conducted in 20.4% to 25.3%. Non execution of the special medical examinations and working environment measurements were mainly due to "lack of knowledge of the law (19.7% and 30.2%)" and "lack of time to perform (16.0% and 23.3%)". Non execution of the controls for the hazardous work factors was due to "lack of knowledge as to how to control (9.0%)", "high costs (7.4%)", "lack of time to perform (6.4%)" and "absence of a suitable adviser (5.9%)". Non execution of the controls for stressful work factors was due to "lack of knowledge as to how to control (15.6%)" and "lack of time to perform (10.2%)". Consequently, as a result of the survey, it was suggested that it is necessary to enlighten the employers of SEEs as to the importance of occupational health controls. It is also necessary to propose low-cost, feasible control methods.

In order to clarify the real conditions of occupational health services (OHS) in small-scale enterprises (SSEs) in Japan, we analyzed questionnaires recovered from 765 SSEs in the area of a city neighboring Osaka City (recovery rate, 69.3%). The SSEs included 358 SSEs with 1 to 4 workers (46.8% of total SSEs), 203 with 5 to 9 (26.5%), 163 with 10 to 29 (21.3%) and 41 with 30 to 49 (5.4%). The main types of businesses were manufacturing (374, 48.9% of total SSEs), wholesale/retail trade/restaurants (153, 20.0%), community, social and personal services (132, 17.3%) and construction (72, 9.4%). Health examinations were performed in 47.7% of SSEs. The reason for the lack of examinations were "shortage of time" (33.3% of SSEs lacking health examination) and "employees do not want to be examined" (28.1%). Some health promotion measures were conducted in 29.2% of SSEs. Health examination (59.0% of SSEs), health promotion (36.5%), measure of mental health (25.9%) and information service for employers and employees (25.5%) were demanded by SSEs as OHS. Financial subsidies and economical incentives were demanded by 46.4% and 28.8% of SSEs, respectively. Regional occupational health center in this area was poorly known among SSEs (8.2%), but health examination (48.4%), information service (37.5%), assessment of work method and advice to improve (19.8%) and environment measurement (12.4%) are demanded of the center by SSEs.

To investigate the risks of developing asbestos-related diseases we conducted a historical cohort mortality study on 249 ship repair workers (90 laggers and 159 boiler repairers) in a single U.S. Navy shipyard in Japan. We successfully identified the vital status of 87 (96.7%) laggers and 150 (94.3%) boiler repairers, and, of these, 49 (56.3%) and 65 (43.3%) died, respectively, during the follow-up period from 1947 till the end of 1996. Our in-person interviews with some of the subjects clarified that asbestos exposure was considered to be substantially high in the 1950-60s, decreased thereafter gradually but remained till 1979 in the shipyard. The laggers, who had handled asbestos materials directly, showed a significantly elevated SMR of 2.75 (95% C.I.: 1.08-6.48) for lung cancer. The risk developing the disease was greater in the laggers after a 20-year latency (SMR=3.42). Pancreatic cancer yielded a greater SMR than unity (7.78, 90% C.I.: 2.07-25.19) in a longer working years group. Four laggers died from asbestosis. The boiler repairers, who had many chances for secondary exposure to asbestos and a few for direct exposure, showed no elevation of the SMR of lung cancer overall, but there was a borderline statistically significant SMR of 2.41 (90% C.I.: 1.05-5.45) in a longer working years group. One boiler repairer died from mesothelioma and four from asbestosis.

This study examined the degree of within-shift variability of short-term exposure concentrations for workers exposed to organic solvents in indoor workplaces. For this purpose, 117 exposure data sets of 15-minute time-weighted average (15-min TWA) and those of 60-min TWA were collected from 53 workers employed in the offset printing, gravure printing, screen printing, machine control board production, fiber-reinforced plastic production, hard metal production, electrical parts production, and chemical synthesizing industries. Data analysis showed that the tenth, fiftieth, and ninetieth percentiles of the geometric standard deviations of 15-min TWA values [GSD(15m)] were 1.4, 2.3, and 4.5, respectively; and those of GSD(60m) were 1.2, 1.7, and 3.4, respectively. Based on an assumption of lognormal exposure distribution, the maximum values of 15-min TWA (the 98.4th percentile) were estimated to be 4.3, 36, and 650 times as high as the minimum one (the 1.6th percentile) for the low, middle, and high exposure variabilities, respectively; and to be 2.0, 4.3, and 8.2 times the 8-hour TWA value, respectively. Consequently, when the 8-hour TWA exceeds 0.23 times (1/4.3) the short-term exposure limit value, the high short-term exposure condition should be evaluated. The maximum values of 60-min TWA (the 93.8th percentile) were estimated to be 1.8, 5.1 and 43 times as high as the minimum one, respectively; and to be 1.3, 2.0, and 3.1 times the 8-hour TWA value, respectively. The relationship between production factors and within-shift exposure variability was also examined. The intermittent solvent use group had significantly higher median values of GSD(15m) and GSD(60m) than the continuous group. The mobile pollutant source group had a significantly higher median value of GSD(60m) than the stationary group.