Biomedical subjects

Sarah E Rogers

Publications and source records attributed to Sarah E Rogers.

4 recordsLinked to original sources

PubMed2006

Fluorosurfactants at structural extremes: adsorption and aggregation.

Fluorosurfactants with several structural modifications have been synthesized, and the air/water interface and bulk aggregation properties investigated. The compounds were fluorinated ethylene oxide (EO) nonionics where the number and position of the hydrophilic group(s) has been radically altered to generate linear, bolaform, and Y-shaped analogues. A noticeable structure-interfacial packing relationship was observed via both tensiometric measurements and neutron reflection studies: the limiting molecular areas, a(cmc), and surface excesses, gamma(cmc), are strongly dependent on the number and position of the EO headgroups. Differing bulk aqueous properties were also observed. Small-angle neutron scattering shows an evolution of micelle structure from cylindrical to disk-like aggregates on changing from Y-shaped to bolaform molecular structure.

Journal Article↗

PubMed2005

Ionic liquid-in-oil microemulsions.

Phase stability and small-angle neutron scattering (SANS) data show that surfactant-stabilized nanodomains of a typical ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4]) may be dispersed by the nonionic surfactant Triton-X100 in cyclohexane. Analyses of these SANS data are consistent with the formation of ionic liquid-in-oil microemulsion droplets.

Journal Article↗

PubMed2005

The Snf1 protein kinase and Sit4 protein phosphatase have opposing functions in regulating TATA-binding protein association with the Saccharomyces cerevisiae INO1 promoter.

To identify the mechanisms by which multiple signaling pathways coordinately affect gene expression, we investigated regulation of the S. cerevisiae INO1 gene. Full activation of INO1 transcription occurs in the absence of inositol and requires the Snf1 protein kinase in addition to other signaling molecules and transcription factors. Here, we present evidence that the Sit4 protein phosphatase negatively regulates INO1 transcription. A mutation in SIT4 was uncovered as a suppressor of the inositol auxotrophy of snf1Delta strains. We found that sit4 mutant strains exhibit an Spt(-) phenotype, suggesting a more general role for Sit4 in transcription. In fact, like the gene-specific regulators of INO1 transcription, Opi1, Ino2, and Ino4, both Snf1 and Sit4 regulate binding of TBP to the INO1 promoter, as determined by chromatin immunoprecipitation analysis. Experiments involving double-mutant strains indicate that the negative effect of Sit4 on INO1 transcription is unlikely to occur through dephosphorylation of histone H3 or Opi1. Sit4 is a known component of the target of rapamycin (TOR) signaling pathway, and treatment of cells with rapamycin reduces INO1 activation. However, analysis of rapamycin-treated cells suggests that Sit4 represses INO1 transcription through multiple mechanisms, only one of which may involve inhibition of TOR signaling.

Alleles↗

PubMed2005

Evaluating a teen STD prevention Web site.

PURPOSE: Teens are at higher risk than other age groups for acquiring sexually transmitted diseases (STDs) because of biological and behavioral risk factors, but they have few STD prevention resources. Little is known about how teens use the Internet to seek this information. A pilot study was conducted to measure audience and information-seeking characteristics of the www.iwannaknow.org Web site. METHODS: In addition to a formative content analysis and a usability study, an online survey was designed, pilot tested, revised, and launched for three months. This paper briefly describes the first two formative study components, and then focuses on the online survey. RESULTS: The content analyses and the usability tests were useful for revising the site content and aesthetics and preparing the online survey. Fewer than half of all participants (N=3,489) were between 13 and 17 (n=1,242), the intended site demographic. Most accessed the Internet from home. The most frequent topic of interest was sexual expression, followed by teen sexuality, virginity, relationships, contraception, and then STD information and these varied by age and gender. CONCLUSIONS: Methods and findings will assist researchers, Web site developers, and health educators to refine these evaluation methods, develop effective Web sites, and tailor STD prevention messages by age group and gender. The Internet is a cost-effective method for educating teens and those who care for or work with teens about STD risks and prevention, however, more research is needed to assess the behavioral effects of online interventions.

Adolescent↗