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Your search keyword '"ROBINSON, J. M."' showing total 38 results
Start Over Author "ROBINSON, J. M." Publisher wiley
38 results on '"ROBINSON, J. M."'

11. ChemInform Abstract: New Preparation of Pyridines from Enamino Nitriles.

Author

ROBINSON, J. M., primary, BRENT, L. W., additional, CHAU, C., additional, FLOYD, K. A., additional, GILLHAM, S. L., additional, MCMAHAN, T. L., additional, MAGDA, D. J., additional, MOTYCKA, T. J., additional, PACK, M. J., additional, ROBERTS, A. L., additional, SEALLY, L. A., additional, SIMPSON, S. L., additional, SMITH, R. R., additional, and ZALESNY, K. N., additional

Published
1993
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35. Where's the glass? Biomarkers, molecular clocks, and microRNAs suggest a 200-Myr missing Precambrian fossil record of siliceous sponge spicules.

Author

Sperling EA, Robinson JM, Pisani D, and Peterson KJ

Subjects
Animals, Biomarkers, Phylogeny, Porifera classification, Fossils, MicroRNAs genetics, Porifera genetics, Porifera metabolism
Abstract

The earliest evidence for animal life comes from the fossil record of 24-isopropylcholestane, a sterane found in Cryogenian deposits, and whose precursors are found in modern demosponges, but not choanoflagellates, calcareans, hexactinellids, or eumetazoans. However, many modern demosponges are also characterized by the presence of siliceous spicules, and there are no convincing demosponge spicules in strata older than the Cambrian. This temporal disparity highlights a problem with our understanding of the Precambrian fossil record--either these supposed demosponge-specific biomarkers were derived from the sterols of some other organism and are simply retained in modern demosponges, or spicules do not primitively characterize crown-group demosponges. Resolving this issue requires resolving the phylogenetic placement of another group of sponges, the hexactinellids, which not only make a spicule thought to be homologous to the spicules of demosponges, but also make their first appearance near the Precambrian/Cambrian boundary. Using two independent analytical approaches and data sets--traditional molecular phylogenetic analyses and the presence or absence of specific microRNA genes--we show that demosponges are monophyletic, and that hexactinellids are their sister group (together forming the Silicea). Thus, spicules must have evolved before the last common ancestor of all living siliceans, suggesting the presence of a significant gap in the silicean spicule fossil record. Molecular divergence estimates date the origin of this last common ancestor well within the Cryogenian, consistent with the biomarker record, and strongly suggests that siliceous spicules were present during the Precambrian but were not preserved.

Published
2010
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36. Biological removal of pyritic sulfur from coal by the thermophilic organism Sulfolobus acidocaldarius.

Author

Kargi F and Robinson JM

Abstract

More than 90% of initial pyritic sulfur was removed from bituminous coal samples (containing 2.1% pyritic sulfur) using the thermophilic organism Sulfolobus acidocaldarius. Microbial desulfurization rate was improved nearly ten fold by adjusting the N/P and N/Mg ratios in the nutrient medium. Environmental conditions were optimized. The optimal values of temperature and pH were 70 degrees C and 1.5, respectively. The influence of certain process variables (such as coal pulp density, particle size, and initial cell number density) on the rate of pyritic sulfur removal were determined. A pulp density of 20%, particle size of D (p) < 48 microm, and an initial cell number density of 10(12) cells/g pyrite in coal were found to be optimal. The carbon dioxide enriched air did not improve the rate of pyritic sulfur removal compared to pure air at 10% pulp density of coal samples containing 2.1% pyritic sulfur. The kinetics of microbial leaching of pyritic sulfur from coal was investigated. The rate of leaching was found to be first order with respect to pyritic sulfur concentration in the reaction medium.

Published
1985
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37. Microbial oxidation of dibenzothiophene by the thermophilic organism Sulfolobus acidocaldarius.

Author

Kargi F and Robinson JM

Abstract

The refractory organic sulfur compound dibenzothiophene (DBT) has been oxidized by the thermophilic, sulfur oxidizing organism Sulfolobus acidocaldarius. Sulfate ions were released into the medium as the oxidation product. The kinetics of this oxidation have been investigated on the basis of sulfate released as a result of oxidation. Dibenzothiophene was found to be inhibitory to the organisms for initial concentrations over 500 mg/L. The organism may prove to be capable of oxidizing thiophene compounds present in oil refinery wastewater, coal, and crude oil.

Published
1984
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