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Biomedical subjects

J Russell

Publications and source records attributed to J Russell.

347 records · Page 20Linked to original sources
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Linking deer browsing and terpene production among genetic identities in Chamaecyparis nootkatensis and Thuja plicata (Cupressaceae).

To investigate whether differential herbivore browsing reflects genetic variation in plant defense expression, variation in needle terpenes and damage caused by black-tailed deer (Odocoileus hemionus) was analyzed on yellow-cedar (Chamaecyparis nootkatensis) and western redcedar (Thuja plicata). In a 100-genet yellow-cedar population, three genets that were heavily browsed and had extremely low levels of monoterpenes (0-0.36% dry matter), sesquiterpenes, and diterpenes were compared to unbrowsed genets (0.85-3.83% monoterpenes in dry matter). These differences were maintained in individuals protected from browsing, suggesting genetically based variation in constitutive terpene production. In western redcedar, heavily browsed trees had significantly lower total monoterpene concentrations (1.69% dry matter) than lightly browsed trees (3.32% dry matter). One heavily browsed tree expressed no monoterpenes. No differences were found for diterpenes. In both species, the genotypes with extremely low monoterpene concentrations came from the same open-pollinated families.

Animals↗
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Approaches to the construction of a medical informatics glossary and thesaurus.

In a project concerned with establishing a glossary and thesaurus for the medical informatics domain, various approaches to the task have been investigated. The developers take the view that a glossary should be a coherent system of terms, reflecting a coherent system of concepts that underlies a body of knowledge about a domain. A framework for the conceptual analysis of the concepts/terms underlying the domain has been developed. The emphasis of this framework is on how the concepts relate together. This work has given an important insight into how the practical task of establishing well-structured vocabularies for a field can be better achieved. An eclectic approach to term selection was adopted. Criteria for assessing what constitutes good definitions for concepts in a field were examined. Using all these approaches glossaries, thesauri and domain models of the medical informatics field are being developed. Another aspect of our work of particular interest is the development of attributed definitions from which inheritance patterns can be defined.

Data Collection↗
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Combined phenyl silane and immunoaffinity column cleanup with liquid chromatography for determination of ochratoxin A in roasted coffee: collaborative study.

A collaborative study was conducted to evaluate a liquid chromatography (LC) method for ochratoxin A using sequential phenyl silane and immunoaffinity column cleanup. The method was tested at 3 different levels of ochratoxin A in roasted coffee, which spanned the range of possible future European regulatory limits. The test portion was extracted with methanol and sodium bicarbonate by shaking for 30 min. The extract was filtered, centrifuged, and then cleaned up on a phenyl silane column before being eluted from the washed column with methanol-water. The eluate was diluted with phosphate-buffered saline (PBS) and applied to an ochratoxin A immunoaffinity column, which was washed with water. The ochratoxin A was eluted with methanol, the solvent was evaporated, and the residue was redissolved in injection solvent. After injection of this solution onto a reversed-phase LC apparatus, ochratoxin A was measured by fluorescence detection. Eight laboratory samples of low-level naturally contaminated roasted coffee and 2 laboratory samples of blank coffee (< 0.2 ng/g ochratoxin A at the signal-to-noise ratio of 3:1), along with ampules of ochratoxin A calibrant and spiking solutions, were sent to 15 laboratories in 13 different European countries. Test portions of the laboratory samples were spiked at levels of 4 ng/g ochratoxin A, and recoveries ranged from 65 to 97%. Based on results for spiked blank material (blind duplicates) and naturally contaminated material (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 2 to 22% and the relative standard deviation for reproducibility (RSDR) ranged from 14 to 26%. The method showed acceptable within- and between-laboratory precision, as evidenced by HORRAT values, at the low level of determination for ochratoxin A in roasted coffee.

Calibration↗