Publications by authors named "Richard Thacker"

Background An overwhelming majority of matriculating medical students in the USA are keen to deliver quality health care to all people, including the socioeconomically disadvantaged populations in remote, resource-scarce regions nationally and worldwide. Here, we describe a protocol developed to evaluate the interest of our medical students in global health activities. We also examined the relationship between students' interest in global health and readiness to pursue a future career in the primary care specialty.

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Choice bioassays were used to determine repellency of homologous n-alkanes (C(8)H(18)-C(21)H(44)) to spider mites. When tested at 400 μg/cm(2), the C(15)-C(19) alkanes were highly repellent; the C(16) n-alkane, n-hexadecane, was most repellent. Subsequently the EC(50) values, the concentration at which 50% of the mites were repelled, were determined for the C(15)-C(19) n-alkanes and their analogous 1-n-alkenes (C(15)H(30)-C(19)H(38)).

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Lycopersicon hirsutum Dunal is very resistant to arthropod herbivory, and research on causes of resistance has often implicated trichomes and their secretions. To better understand relationships among resistance, repellency, and 2,3-dihydrofarnesoic acid, a trichome-borne sesquiterpenoid spider mite repellent, two tomato, Lycopersicon esculentum Miller, varieties were interbred with a highly resistant, spider mite repellent accession (LA1363) of L. hirsutum.

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Two tomato (Lycopersicon esculentum) mutants with dark testae displaying poor germination rate and percentage on both water and 100 microM gibberellin(4 + 7) were recovered. The mutants were allelic (black seed1-1; bks1-1 and bks1-2), inherited in Mendelian fashion as a recessive gene residing on chromosome 11. They are not allelic to bs (brown seed) -1, -2, or -4, which impair seed germination and possess dark testae.

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Raffinose family oligosaccharides (RFOs) have been implicated in mitigating the effects of environmental stresses on plants. In seeds, proposed roles for RFOs include protecting cellular integrity during desiccation and/or imbibition, extending longevity in the dehydrated state, and providing substrates for energy generation during germination. A gene encoding galactinol synthase (GOLS), the first committed enzyme in the biosynthesis of RFOs, was cloned from tomato (Lycopersicon esculentum Mill.

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