Implementation of an excess sludge reduction step in an activated sludge process.

In this study, excess sewage sludge reduction resulting from the modification of an activated sludge process by incorporation of an excess sludge digesting reactor (ESDR) was examined. The ESDR was coupled to the sludge return line, and enhanced the solubilization of cell mass under thermophilic aerobic conditions. The decrease in the level of total suspended solids (TSS) observed in the reference ESDR (without thermophilic microbial inoculation) was 13.76% whereas a TSS decrease of 32.09% was achieved by the test ESDR (with thermophiles), thus showing microbial enhancement of solubilization of 18.33% over a test period of 48 h. The average excess sludge solubilization ratios (beta values) of TSS were 51.17% and 41.56% in two distinct protocols varying in operative parameters. The calculated excess sludge reduction ratio was 49.60% with a sludge recirculation ratio of 2, but increased to 68.97% when the sludge recirculation ratio rose to 3. The sludge volume indexes (SVIs) for the control and test processes were 68.4 and 57.0 respectively, indicating the absence of any negative effect of the modification on sludge settling characteristics. Effluent water quality satisfied national legislative requirements.

ITPKC and SLC11A1 Gene Polymorphisms and Gene-Gene Interactions in Korean Patients with Kawasaki Disease.

PURPOSE: Kawasaki disease (KD) is an acute systemic vasculitis. Both the etiology of KD and the erythema of Bacille Calmette-Guérin (BCG) injection sites observed in the disease are poorly understood. We investigated the association between KD and single nucleotide polymorphisms (SNPs) in two candidate genes: inositol 1,4,5-triphosphate 3-kinase (ITPKC), a well-studied KD-associated gene, and solute carrier 11a1 (SLC11A1), which is associated with the hypersensitive reaction to the BCG strain in Koreans. MATERIALS AND METHODS: Associations between KD and SNPs in two genes were evaluated. Potential associations between BCG injection site erythema and SNPs in two genes were also evaluated. Gene-gene interactions between ITPKC and SLC11A1 in KD and BCG injection site erythema were also analyzed. RESULTS: Three tagging SNPs in ITPKC and five tagging SNPs in SLC11A1 were genotyped in 299 KD patients and 210 control children. SNP rs28493229 in ITPKC was associated with KD and coronary artery complications. SNP rs77624405 in SLC11A1 was associated with KD. Comparisons of KD patients with and without BCG injection site erythema revealed that SNP rs17235409 in SLC11A1 was associated with erythema; no erythema-associated SNPs in ITPKC were identified. Interactions between ITPKC rs28493229_GG and SLC11A1 rs17235409_GA and between ITPKC rs10420685_GG and SLC11A1 rs17235409_AA were strongly associated with BCG injection site erythema. CONCLUSION: This study identified several important polymorphisms in the ITPKC and SLC11A1 genes in Koreans. The genetic variants identified in this study affected KD and erythema of BCG injection sites independently and through gene-gene interactions. Also, the effects of the polymorphisms were age-dependent.

Mitochondrial DNA haplogroup analysis reveals no association between the common genetic lineages and prostate cancer in the Korean population.

Mitochondrial DNA (mtDNA) variation has recently been suggested to have an association with various cancers, including prostate cancer risk, in human populations. Since mtDNA is haploid and lacks recombination, specific mutations in the mtDNA genome associated with human diseases arise and remain in particular genetic backgrounds referred to as haplogroups. To assess the possible contribution of mtDNA haplogroup-specific mutations to the occurrence of prostate cancer, we have therefore performed a population-based study of a prostate cancer cases and corresponding controls from the Korean population. No statistically significant difference in the distribution of mtDNA haplogroup frequencies was observed between the case and control groups of Koreans. Thus, our data imply that specific mtDNA mutations/lineages did not appear to have a significant effect on a predisposition to prostate cancer in the Korean population, although larger sample sizes are necessary to validate our results.

Lack of association between Y-chromosomal haplogroups and prostate cancer in the Korean population.

The Y chromosome has recently been suggested to have an association with prostate cancer risk in human populations. Since this chromosome is haploid and lacks recombination over most of its length, haplotypes constructed from binary markers throughout the chromosome can be used for association studies. To assess the possible Y-chromosomal contribution to prostate cancer risk, we have therefore analyzed 14 Y-chromosomal binary markers in 106 prostate cancer cases and 110 controls from the Korean population. In contrast to previous findings in the Japanese population, no statistically significant difference in the distribution of Y-chromosomal haplogroup frequencies was observed between the case and control groups of Koreans. Thus, our data imply that the previously reported associations between Y-chromosomal lineages and a predisposition to, or protection against, prostate cancer might be explained by statistical fluctuations, or by genetic effects that are seen only in some environments.