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S N Lewis

Publications and source records attributed to S N Lewis.

7 recordsLinked to original sources
PubMed1991

Degradation of organic sulfur compounds by a coal-solubilizing fungus.

Paecilomyces sp. TLi, a coal-solubilizing fungus, was shown to degrade organic sulfur-containing coal substructure compounds. Dibenzothiophene was degraded via a sulfur-oxidizing pathway to 2,2'-dihydroxybiphenyl. No further metabolism of that compound was observed. Ethyl phenyl sulfide and diphenyl sulfide were degraded to the corresponding sulfones. A variety of products were formed from dibenzyl sulfide, presumably via free radical intermediates. Diphenyl disulfide and dibenzyl disulfide were cleaved to the corresponding thiols and other single-ring products. It was concluded that degradation of organic sulfur compounds by Paecilomyces involves an oxidative attack localized at the sulfur atom.

Biodegradation, Environmental↗
PubMed1990

Binding of Dissolved Strontium by Micrococcus luteus.

Resting cells of Micrococcus luteus have been shown to remove strontium (Sr) from dilute aqueous solutions of SrCl(2) at pH 7. Loadings of 25 mg of Sr per g of cell dry weight were achieved by cells exposed to a solution containing 50 ppm (mg/liter) of Sr. Sr binding occurred in the absence of nutrients and did not require metabolic activity. Initial binding was quite rapid (<0.5 h), although a slow, spontaneous release of Sr was observed over time. Sr binding was inhibited in the presence of polyvalent cations but not monovalent cations. Ca and Sr were bound preferentially over all other cations tested. Sr-binding activity was localized on the cell envelope and was sensitive to various chemical and physical pretreatments. Bound Sr was displaced by divalent ions or by H. Other monovalent ions were less effective. Bound Sr was also removed by various chelating agents. It was concluded that Sr binding by M. luteus is a reversible equilibrium process. Both ion exchange mediated by acidic cell surface components and intracellular uptake may be involved in this activity.

Journal Article↗
PubMed1989

What makes a vibble a vibble? A developmental study of category generalization.

Young children appear to know when a novel label for a novel object is a common noun. The present study was concerned with the properties of a named object that children assume to be true of other members of the category that is specified by such a noun. Preschoolers, second graders, and college students were shown drawings of objects and given nonsense labels for those objects. They then viewed other objects that varied from the labeled ones along 4 particular attributes and were asked to decide if those other objects should also receive the same label. Preschoolers focused mostly on single attributes in making category decisions, and their choices of attributes were evenly distributed among the 4 types. Older individuals primarily exhibited multiple attribute rules. The results are discussed in terms of developmental differences in the modes of processing that are used and in the types of knowledge that are brought to bear on the word learning situation.

Attention↗
PubMed1988

The transition to parenthood in dual-earner couples.

The impact of the transition to parenthood for dual-earner couples was examined in a longitudinal study. Data were collected by questionnaire from couples expecting their first child, during pregnancy and after maternity leave, and from childless couples at two separate time points. The impact of the transition was minimal overall, although women experienced more pressure than men and there were some cases of extreme stress. New single-earner parents reported a greater decline in life satisfaction than dual-earners.

Adaptation, Psychological↗