Centroid neural network for unsupervised competitive learning.

An unsupervised competitive learning algorithm based on the classical -means clustering algorithm is proposed. The proposed learning algorithm called the centroid neural network (CNN) estimates centroids of the related cluster groups in training date. This paper also explains algorithmic relationships among the CNN and some of the conventional unsupervised competitive learning algorithms including Kohonen's self-organizing map (SOM) and Kosko's differential competitive learning (DCL) algorithm.

General preparation and controlled cyclization of acyclic terpenoids.

A general preparation method of the all-(E)-polyprenols 12 has been developed from readily available geranyl sulfone by the chain-extension process utilizing the C5 unit 5 and the chain-termination process utilizing the C5 unit 10 together with the chemoselective reductive desulfonylation. The polyprenols 12 were converted to compounds 3 containing two consecutive prenyl sulfone moieties at the tail end, which underwent the controlled electrophilic cyclization only at the carbon-carbon double bonds that were remote from the flat and rigid benzenesulfonyl groups.

A study on nutrition knowledge and dietary behavior of elementary school children in Seoul.

The purpose of this study was to investigate the nutrition and diet related knowledge, attitude, and behavior of elementary school children in Seoul. The subjects included were 439 (male 236, female 203) elementary school children in the 4th to the 6th grades. The statistical analysis was conducted using SPSS 12.

Stereoselective synthesis of allylic sulfones via the oxonia-Cope rearrangement of homoallylic alcohols containing a homoallylic sulfone moiety.

The homoallylic alcohols 3 that can be prepared by the indium-mediated addition of haloallylic sulfones 1 to aldehydes 2 undergo the oxonia-Cope rearrangement with aldehydes 2 to give rise to the allylic sulfones 4 containing a conjugated diene moiety in a highly stereoselective manner. Electron-rich aldehydes preferentially participate in this oxonia-Cope rearrangement with the homoallylic alcohols 3. Excellent correlations of the stereochemistry (anti-3 to trans-allylic sulfone 4 and syn-3 to cis-allylic sulfone 4) have been observed in the oxonia-Cope rearrangement.

Origin of the diastereoselection in the indium-mediated addition of haloallylic sulfones to aldehydes.

[reaction: see text] The R(1) substituents at C(2) of the haloallylic sulfones 1 play a pivotal role in controlling the diastereoselectivity of the indium-mediated addition reaction to benzaldehyde to produce the homoallylic alcohols 3. The R(1) Me group of 1 prefers the chair form in the In-coordinated six-membered cyclic transition state to give anti-3a, and the R(1) Ph group of 1 favors the twist boat form to give syn-3n, both in a high 13:1 selectivity.

Performance evaluation of pilot scale sulfur-oxidizing denitrification for treatment of metal plating wastewater.

A full-scale and two pilot-scale upflow sulfur-oxidizing denitrification (SOD) columns were evaluated using metal plating wastewater as feed. The sludge was autotrophically enriched, and inoculated in the SOD columns attached to the effluent line of three metal plating wastewater treatment facilities. The effects of activated carbon and aeration were also studied, and found effective for the removal of suspended solids and ammonia, respectively.

Sulfone coupling and double-elimination strategy for carotenoid synthesis.

[Reaction: see text]. A highly efficient synthetic method of carotenoid compounds has been developed on the basis of the sulfone coupling and double-elimination strategy. This method highlighted the sulfone-mediated coupling with the novel C(10) dialdehyde, 2,7-dimethyl-4-octenedial, which was easily prepared and efficiently utilized in the synthesis of the conjugated polyene chains.

Preparation of 1,4-hydrobenzoquinones by the PCC/SiO2-promoted double oxidation of 3-cyclohexene-1,2-diols.

The PCC/SiO2-promoted double oxidation of 3-cyclohexene-1,2-diols, which were easily prepared by the two-step sequence of alpha'-hydroxylation of various conjugated cyclohexenones and the subsequent nucleophilic carbonyl addition of alkyl anions, produced diversely substituted 1,4-hydrobenzoquinones.

Efficient syntheses of the keto-carotenoids canthaxanthin, astaxanthin, and astacene.

Three keto-carotenoids were prepared by the oxidation of the stable C(40) trisulfone 6, which has been used as the key compound in our beta-carotene synthesis. The first allylic oxidation to the unsaturated ketone and the second oxidation to the alpha-hydroxyketone produced the C(40) trisulfones 7 and 10, respectively. The Ramberg-Backlund reaction of the oxidized C(40) trisulfone was efficiently effected by the use of a mild base, NaOMe, in the presence of CCl(4) as a halogenating agent to give the C(40) disulfones 8 and 11.

Kribbella solani sp. nov. and Kribbella jejuensis sp. nov., isolated from potato tuber and soil in Jeju, Korea.

Two actinomycete strains, DSA1T and HD9T, were isolated from a potato tuber and soil from a potato-cultivating field in Jeju, Korea, respectively. A comprehensive 16S rDNA analysis revealed that the isolates belong to the genus Kribbella and share 97.7-98.

Phylogenetic analysis of Streptomyces spp. isolated from potato scab lesions in Korea on the basis of 16S rRNA gene and 16S-23S rDNA internally transcribed spacer sequences.

The 16S rRNA gene sequences for 34 strains, including 11 isolates, were determined to classify scab-causing Streptomyces spp. and relatives isolated from potato scab lesions collected in Jeju, Korea. The 16S-23S rDNA internally transcribed spacer (ITS) sequences were determined to investigate whether the 16S-23S ITS region is useful for analysing intra- and interspecific relationships in these bacteria.

The intramolecular Baylis-Hillman reaction: easy preparation of versatile substrates, facile reactions, and synthetic applications.

We have developed a general and highly efficient method for the preparation of diverse [small omega]-formyl-[small alpha],[small beta]-unsaturated carbonyl compounds and optimized the conditions for the intramolecular Baylis-Hillman reactions of these compounds to provide various biologically important polycyclic compounds.

The Friedel-Crafts allylation of a prenyl group stabilized by a sulfone moiety: expeditious syntheses of ubiquinones and menaquinones.

An efficient synthetic method for the protected p-hydroquinone compounds 4 containing the C5 trans allylic sulfone moiety has been developed by the direct Friedel-Crafts allylation of the protected dihydroquinone 2 with 4-chloro-2-methyl-1-phenylsulfonyl-2-butene (7a) or 4-hydroxy-2-methyl-1-phenylsulfonyl-2-butene (7b). Expeditious total syntheses of coenzyme Q-10 and vitamin K2(20) have been demonstrated from these valuable key compounds 4a and 4b.

Isolation and characterization of bluensomycin biosynthetic genes from Streptomyces bluensis.

The biosynthetic gene cluster for bluensomycin, a member of the aminoglycoside family of antibiotics, was isolated and characterized from the bluensomycin producing strain, Streptomyces bluensis ATCC27420. PCR primers were designed specifically to amplify a segment of the dTDP-glucose synthase gene based on its conserved sequences among several actinomycete strains. By screening a cosmid library using amplified PCR fragments, a 30-kb DNA fragment was isolated.

Alteration of substrate specificity of valine dehydrogenase from Streptomyces albus.

The catabolism of branched chain amino acids, especially valine, appears to play an important role in furnishing building blocks for macrolide and polyether antibiotic biosyntheses. To determine the active site residues of ValDH, we previously cloned, partially characterized, and identified the active site (lysine) of Streptomyces albus ValDH. Here we report further characterization of S.

NBS-Promoted reactions of symmetrically hindered methylphenols via p-benzoquinone methide.

Symmetrically hindered methylphenols 1 react smoothly with NBS to form transient intermediates, p-benzoquinone methides (BM), which can be further processed to give hydroxybenzaldehydes in the presence of DMSO. This reaction is initiated by the formation of the phenoxy radical, followed by disproportionation to afford BM. None of the side-chain-brominated product is observed.

An efficient approach for cloning the dNDP-glucose synthase gene from actinomycetes and its application in Streptomyces spectabilis, a spectinomycin producer.

Specifically designed PCR primers were applied to amplify a segment of dTDP-glucose synthase gene from six actinomycete strains. About 300-bp or 580-bp DNA fragments were obtained from all the organisms tested. By DNA sequence analysis, seven amplified fragments showed high homology with dTDP-glucose synthase genes that participate in the biosynthesis of secondary metabolites or in deoxy-sugar moieties in lipopolysaccharides.

Valine dehydrogenase from Streptomyces albus: gene cloning, heterologous expression and identification of active site by site-directed mutagenesis.

A gene encoding valine dehydrogenase (Vdh) has been cloned from Streptomyces albus, a salinomycin producer, and expressed in Escherichia coli. The S. albus Vdh is composed of 364 amino acids that showed high homology with several other amino acid dehydrogenases as well as Vdhs from Streptomyces spp.

Effects of radial wall motion and flow waveform on the wall shear rate distribution in the divergent vascular graft.

Among the hemodynamic factors influencing intimal hyperplasia in the anastomotic region of a vascular graft, wall shear rate is believed to be one of the most important. We would like to study the effects radial wall motion on the wall shear rate distribution in the end-to-end anastomosis model of an artery and a divergent graft. Rigid and elastic models are constructed and the wall shear rate distributions are measured along the anastomosis using photochromic flow visualization method for carotid and femoral flow waveform.

Sequence variation of EBNA2 of Epstein-Barr virus isolates from Korea.

To reveal sequence variations in the Epstein-Barr virus nuclear antigen 2 (EBNA2) genes of Epstein-Barr virus (EBV) strains circulating in the Korean population, the EBNA2 divergent region was amplified and sequenced from 13 EBV-1 isolates, 2 EBNA2 type 1 intertypic EBV isolates, and two EBV-2 isolates, all derived from Korean cancer patients. Comparative sequence analysis revealed that type 1 and type 2 EBNA2 divergent regions of Korean EBV isolates were almost identical to the respective regions of the B95-8 EBV-1 and AG876 EBV-2 strains. Two of the nucleotide changes found in the type 1 divergent regions of all Korean isolates, G-to-T and C-to-A at B95-8 EBV positions 48,991 and 48,998, respectively, are also present in all EBV-1 strains of non-Asian origins, indicating that these two sites might be mutational hot sites.

Sequencing and chromosomal localization of the RA138 gene encoding a rice allergenic protein.

A cDNA clone (RA138) encoding a rice allergenic (RA) protein has been isolated during a large-scale random sequencing of a cDNA library prepared from developing seeds. The nucleotide sequence of the RA138 gene contained an open reading frame (ORF, 477 bp) encoding a 17 kDa protein. The amino acid sequence deduced from the ORF was composed of 159 amino acid residues and was highly homologous to those from RA genes previously isolated, such as RA5 (92% identity), RA14 (73%), and RA17 (68%).

Purification and characterization of acid-type phosphatases from a heavy-metal-accumulating Citrobacter sp.

An acid phosphatase from a heavy-metal-accumulating strain of a Citrobacter sp. was resolved into two forms on the basis of their nonbinding (phosphatase I) or binding (phosphatase II) behaviour on the cation-exchange resin SP-Sephadex C50. Both holoenzymes had a molecular mass of 103-108 kDa as determined by Superose Q-6 column chromatography in the presence of 150 mM KCl and a subunit molecular mass of 27 kDa as determined by SDS-PAGE; the enzyme was tetrameric.

[The ideal and practice of Greek medical ethics].

This paper is concerned not with medical theories, but with practices of Greek physicians, and I have addressed the subject of medical ethics as related to the Hippocratic tradition. And I have attempted a synthetic account of Greek physicians' actual practice and its ideals in the Hippocratic tradition. My understanding of the tradition succeeds the revelations in the first chapter of my doctoral dissertation, one of them is the fact that Hippocratic tradition is amalgamation of ethical code with rational or scientific medical theory.