No abstract

Poly‐(2‐ethynylpyridinum bromide) (PEPBP) having propargyl side chains was prepared by the direct polymerization of 2‐ethynylpyridine and propargyl bromide under mild reaction conditions without any initiator and catalysts. The polymerization proceeded well to give PEPBP with propargyl side chains in relatively high yields. Various spectral data for the polymer structure indicated that the conjugated polymer system having N‐propargylpyridinum substituent was formed. This ionic polymer was completely soluble in water, methanol, dimethylformamide, dimethyl sulfoxide, and N,N‐dimethylacetamide and well processable into thin homogeneous film. The photoluminescence intensity (λmax = 760 nm) of this polymer increased as the temperature was increased. At 1 KHz and room temperature, this polymer has k′ = 2.9 and σ = 7.3 × 10−10 (S/cm). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3151–3158, 2001

PurposeThe purpose of this retrospective study was to evaluate the effect of patient compliance with supportive periodontal therapy (SPT) on tooth loss in Korean adults.MethodsThe periodontal records of 134 patients were reviewed for this study. They completed active periodontal treatment from 1999 to 2001 and were placed on a schedule of periodic follow-up visits for SPT. Patient compliance was classified into complete compliance (CC), erratic compliance (EC), and noncompliance (NC) groups. Re-examinations were carried out 11.0±0.8 years after the active periodontal treatment. The prognosis for each tooth was determined as good, questionable, or hopeless according to the bone loss observed in pretreatment radiographs.ResultsThe rate of tooth loss of the CC group was significantly lower than that of the NC group. The tooth loss/patient and the tooth loss/patient/year were not significantly different between the three groups. The rates of tooth loss in the good, questionable, and hopeless prognosis groups were 6.7%, 9.5%, and 13.2%, respectively. For the teeth with a good prognosis, the rate of tooth loss of the CC group was significantly lower than that of the NC group (0.4% vs. 5.1%). For the teeth with a questionable prognosis, the CC group showed a significantly lower rate of tooth loss than did the EC group (4.1% vs. 30.7%) or the NC group (4.1% vs. 25.6%). For the teeth with a hopeless prognosis, the rates of tooth loss were not significantly different among the three groups.ConclusionsWithin the limits of this study, the patients who showed a poor compliance with SPT were more likely to lose teeth than were the regularly compliant patients. However, the risk of tooth loss with a hopeless prognosis was high irrespective of the compliance.Graphical Abstract

This study was based on the investigation of Pb, Cd, Ca, and Cl in one individual batch of bottom ash and fly ash (mixture 5:1) resulting from a specific municipal solid waste incinerator (MSWI) in Japan. This mixture ash was stabilized as the following pretreatments: water washing, carbonation, and phosphate stabilization.After the optimum processing condition for each pretreatment was determined, the performance of each pretreatment was examined using pH stat leaching tests (pH 6, 9, 12) and availability tests. For the performance tests, fly ash alone was used, instead of a mixture of MSWI residues, to observe leaching differences among the pretreatments more distinctly.Water washing effectively removed the major elements from MSWI residues and also reduced the leachability of trace metals, such as Pb and Cd, from MSWI residues. A washing time of 15 min with an L/S ratio of 5 was reasonably effective.Carbonation had a significant effect on leachability in alkaline ranges (pH 9 and 12), due to carbonation only on the surface of MSWI residues, not in the center matrix. A moisture content of 10-16.7% appeared to be suitable for carbonation. Phosphate stabilization, even with small doses of phosphate (0.16 mol-PO 4 3-kg -1 sample), was very effective at reducing the leachability of heavy metals.

Two new pre-treatment methods (water-washing/carbonation and carbonation/phosphate stabilisation) of municipal solid waste (MSW) incinerator residues were evaluated by column leaching tests under aerobic conditions and anaerobic conditions (which were changed to aerobic conditions after 10 months). A mixture of bottom ash and fly ash (5:1 ratio) was pre-treated using each method. Shredded incombustible residues (SIR) were added to each ash preparation in proportions similar to the ratios present in landfills. For comparison, landfill wastes typical of Japan, i.e., a mixture of bottom ash, chelating-pre-treated fly ash, and SIR, were also examined. Leachate samples were collected periodically and analysed over a 15-month period.When compared to chelating pre-treatment, both water-washing/carbonation and carbonation/phosphate stabilisation reduced the leaching of Pb, Al, and Cu by about 1-2 orders of magnitude. Moreover, the initial concentrations of Ca and Pb in leachates from column of water-washing/carbonation were 56-57% and 84-96% less than those from column of carbonation/phosphate stabilisation. Therefore, water-washing/carbonation was considered to be a promising approach to obtain early waste stabilisation and to reduce the release of heavy metals to near-negligible levels. The leaching behaviour of elements was also discussed.