Proportion Of Tri Research Articles

Problems in plutonium chemistry: Generalized proportional equations and polymer formation

This paper illustrates a generalized form of the method of proportional equations. It permits equilibrium calculations for Pu disproportionation reactions at any oxidation number and any pH by means of combining arbitrary proportions of tri- and hexavalent plutonium. Two methods for estimating the work of Pu polymer formation are illustrated. One method uses the work of disproportionation of tetravalent plutonium. The other method suggests the transition between hydrous Pu(IV) oxide and polymer is accompanied by a small change in free energy.

Recent contamination by persistent organochlorines in Baikal seal ( Phoca sibirica) from Lake Baikal, Russia

Blubber samples of Baikal seals pups ( Phoca sibirica) collected in 2001 and 2002 were analyzed for persistent organochlorines (OCs) such as PCBs (polychlorinated biphenyls), DDTs (dichlorodiphenyltrichloroethane and its metabolites), HCHs (hexachlorocyclohexane isomers), CHLs (chlordane related compounds), TCPMe [ tris(4-chlorophenyl)methane] and TCPMOH [ tris(4-chlorophenyl)methanol]. The distribution pattern of OCs was in the following order: DDTs > PCBs > CHLs > HCHs > TCPMOH > TCPMe. Organochlorine concentrations and composition patterns in eight pup blubber samples (2002) analyzed in the present study were compared with the corresponding levels in juvenile Baikal seals from 1992 survey, and it was found that residue levels of OC compounds have declined during the 10 year period. In particular, concentrations of PCBs, HCHs and CHLs in seals collected in 2002 were approximately two times lower, while DDTs levels were three times lower than the corresponding levels in 1992. Furthermore, higher ratios of β-HCH/HCHs and p, p ′-DDE/DDTs were found in 2002 samples. While comparing the OC levels with those in other seal pups it appeared that all the OC concentrations were lower than the levels in seals from coastal California known as one of the most polluted areas. PCB and DDT concentrations in the present specimens were higher than that in Arctic seal pups. The proportions of tri-, tetra-, penta- and hexachlorobiphenyls in pups captured in 2002 were higher than those in 1992. TEQ concentrations of non- and mono- ortho coplanar PCBs in Baikal seals collected in 2002 were higher than those in seals collected from some locations in the world, where human and industrial activities are extensive, suggesting potential for toxic implications of coplanar PCBs in Baikal seals.

Polymorphic microsatellites from silver crucian carp (Carassius auratus gibelio Bloch) and cross-amplification in common carp (Cyprinus carpio L.)

Fifteen polymorphic microsatellites were isolated from the genome of silver crucian carp (Carassius auratus gibelio Bloch). Allele numbers ranged from two to four with an average of 2.7/locus, and the proportion of tri- and diallelic heterozygotes was 99.3%. The individuals tested seem to have originated from two different clonal lines: 14 of 16 showed the same genotype at all loci tested, whereas the remaining two were also identical, but different from the former ones. Eleven out of 15 primer pairs cross-amplified products from the genome of common carp, whereas only five from that of zebrafish.

Chlorobiphenyl contaminants at Pladda and Garroch Head in the Firth of Clyde following the cessation of sewage sludge dumping

Sewage sludge dumping at Garroch Head in the Firth of Clyde ceased on 31 December 1998. Eighteen of the 209 chlorinated biphenyls (CBs) were measured in plaice livers, collected in 1999 and 2000, from the former Garroch Head dump site. Samples were also obtained from Pladda, a site reasonably remote from the former dump site but also in the Clyde, in 1999 only. These results were compared to the CB concentrations in plaice livers collected between 1992 and 1998 from Garroch Head and Pladda. Additional samples were also taken from a clean reference site, close to Colonsay. Concentrations of the congeners in the livers of fish caught at the former Garroch Head dump site in 1999 were marginally higher than those from Pladda, with a mean CB concentration of 1861 microg kg(-1) lipid in the Garroch Head plaice livers and 1725 microg kg(-1) lipid for the sample from Pladda. The mean CB concentration in the 2000 Garroch Head samples was 2253 microg kg(-1) lipid. CB concentration in plaice livers from Colonsay were lower than both the Pladda and Garroch Head fish, with plaice livers from Colonsay giving a mean CB concentration of 1076 microg kg(-1) lipid in 1999 and 345.1 microg kg(-1) lipid in 2000. The data was evaluated using principal component analysis (PCA). Pattern analysis was undertaken by normalising to the recalcitrant CB 153. There was an indication that the CB pattern has changed since the cessation of dumping with the proportion of tri- and tetra-chlorinated CBs being lower in plaice from Garroch Head than in previous years.

Genetic significance of mode of polyploidization: somatic doubling or 2n gametes?

Computer simulation was undertaken to compare the genetic consequences of asexual (somatic doubling) and sexual (2n gametes) polyploidization. The coefficient of inbreeding at a locus, the number and frequency of genotypes at a locus, and the proportion of tri- and tetra-allelic genotypes were considered. The factors considered to estimate the genetic consequences were (i) mechanisms of sexual polyploidization, by first division restitution (FDR) × second division restitution (SDR), FDR × FDR, or SDR × SDR; (ii) position of the locus in relation to the centromere, which affects the gametic output in 2n gamete formation and thus the probability of single-exchange tetrads in meiosis during 2n gamete formation (p value); and (iii) allelic diversity at a locus. In comparing asexual and sexual polyploidization, regardless of the position of a locus in relation to the centromere, sexual polyploidization generally indicated less inbreeding, more genotypic diversity, and a higher proportion of tri- and tetra-allelic genotypes. When allelic diversity at a locus was increased, these characteristics were even more prominent. When only two alleles are possible at a locus, somatic doubling would not be inferior to sexual polyploidization. Overall results favored SDR × FDR and FDR × FDR as a mode and mechanisms of polyploidization. The genetic variations produced by 2n gametes could be attributed to "combining ability of 2n gametes."Key words: asexual polyploidization, sexual polyploidization, inbreeding, heterozygosity, combining ability of 2n gametes.

Isolation and structural characterization of human lymphocyte neutral glycosphingolipids.

The neutral glycosphingolipids of human peripheral blood lymphocytes and of the lymphoid cells from a patient with B cell chronic lymphocytic leukemia were chemically analyzed. Four neutral glycosphingolipids were chemically analyzed. Four neutral glycosphingolipids were isolated from each of these two sources and studied by gas chromatography, methylation analysis, and electron impact--desorption mass spectrometry. The results of these studies indicate that the compounds have the following structures: Glc1 leads to 1Cer Gal1 leads to 4Glc1 leads to 1Cer Gal1 leads to 4Gal1 leads to 4Glc1 leads to 1Cer GalNAc1 leads to 3Gal1 leads to 4Gal1 leads to 4Glc1 leads to 1Cer These compounds, belonging to the globo series, were the only neutral glycosphingolipids found in the lymphoid cells. The ceramide (Cer) moiety of all these compounds contained 4-sphingenine with C16:0, C24:0, and C24:1 as the major fatty acid species. There were no structural differences in the neutral glycosphingolipids of peripheral blood lymphocytes compared to those of chronic lymphocytic leukemia cells. Peripheral blood lymphocytes contained more di- than monohexosylceramide whereas the reverse was true of the chronic lymphocytic leukemia cells. The proportion of tri- and tetrahexosylceramide was less than 10% for both types of cells. The results of our analyses did not support the existence of any differences in the major neutral glycosphingolipids among T, B, and chronic lymphocytic leukemia cells.

The turnover of thyroxine in the plasma of the domestic fowl (Gallus domesticus).

Abstract A method for estimating thyroid activity in the chicken by measuring the plasma[ 125 I]-thyroxine ([ 125 I]T 4 ) degradation rate is described. The initial disappearance curve for plasma [ 125 I]T 4 was triphasic representing the dilution, extravascular distribution, and fractional turnover of T 4 , respectively. The curve represented fractional turnover between 2 and 9 hr after [ 125 I]T 4 injection. Thereafter, it changed as the proportion of tri-[ 125 I]iodothyronine increased and radioiodide was recycled. The plasma half-life of thyroxine was 206 min when total plasma 125 I was used as an estimate of [ 125 I]T 4 but 138 min when the hormonal fraction was extracted on cation-exchange resin. Plasma protein-bound radioiodide overestimated [ 125 I]T 4 due to the presence of as yet unidentified nonhormonal iodinated proteins.

Reaction of acylated methyl arabinosides with hydrogen bromide

Treatment of methyl tri- O-acetyl-β- D-arabinopyranoside ( 1a) with hydrogen bromide in benzene or in acetic acid gave, in addition to the pyranosyl bromide ( 2a), a considerable proportion of tri- O-acetyl- D-arabinofuranosyl bromide ( 5). Similar treatment of methyl tri- O-benzoyl-β- D-arabinopyranoside ( 1b) gave a good yield of the pyranosyl bromide ( 2b); no furanoid derivative was formed. Ring contraction also took place when methyl 4- O-acetyl-2,3-di- O-benzoyl-β- D-arabinopyranoside ( 7) was treated with hydrogen bromide, whereas the isomeric 3- O-acetyl-2,4-di- O-benzoyl compound ( 12) gave the pyranosyl bromide 13 in high yield. Thus, methyl pyranosides with an O-acetyl group at C-4 undergo ring contraction on treatment with hydrogen bromide. The corresponding compounds with O-benzoyl groups at C-4 gave pyranosyl bromides only.