Faculty Bibliography

Current symbolic techniques for the automated reasoning over undecidable hybrid automata, force one to choose between the refinement of either an overapproximation or an underapproximation of the set of reachable states. When the analysis of branching time temporal properties is considered, the literature has developed a number of abstractions techniques based on the simulation preorder, that allow the preservation of only true universally quantified formulæ. This paper suggests a way to surmount these difficulties by defining a succession of abstractions of hybrid automata, which not only (1) allow the detection and the refinement of both over- and under-approximated reachable sets symmetrically, but also (2) preserves the full set of branching time temporal properties (when interpreted on a dense time domain). Moreover, our approach imposes on the corresponding set of abstractions a desirable monotonicity property with respect to the set of model-checked formulaæ.

INTRODUCTION: A gap exists between asthma guidelines and actual care delivered. We developed an educational intervention using simulated physician-patient encounters as part of a project to improve asthma management by community-based primary care providers. We hypothesized that this type of skills-based interactive training would improve learners' care choices for simulated patients after training compared with their choices before training. METHODS: After a pilot project was done on a small group of providers, a larger group of primary care providers (PCPs) was recruited to be trained with our interactive materials. The pilot session, with 39 providers, showed that the cases were felt to be appropriate, that the time allocated for discussion was adequate, that the models were useful, that the experience was educational, and that the experience captured their interest. Two subsequent training sessions were held with 240 PCPs. Participants completed a questionnaire to elicit perceived barriers and self-efficacy and then viewed a short simulated physician-patient dialogue. They then completed a set of scaled questions about treatment choices. This served as a pretest assessment. A similar simulation was then shown, and the group discussed their thoughts on diagnosis and treatment. Finally, they viewed another physician-patient interaction and responded to the same questions as posed for the pretest assessment; the responses before and after assessment were compared. RESULTS: Following completion of the intervention, providers were significantly (p < 0.05) more likely to make use of controller medications, asthma equipment, and patient training. Significant (p < 0.05) increases were also seen in action plan development and the availability of office visits. Providers were significantly (p < 0.05) less likely to refer asthma patients to an emergency department or for hospitalization. Significant (p < 0.05) improvements were also seen in perceptions of self-efficacy and barriers to treatment. There were significant (p < 0.05) increases in learners' confidence about their own and patients' abilities to improve asthma care, and fewer barriers to asthma management were reported after the training. DISCUSSION: This method of training resulted in learners showing a measurable improvement in their intent to follow guidelines as applied to simulated patients. An evaluation addressing actual patient outcomes will need to be done.

The polarized distribution of K(+) channels in MDCK cells is lost upon harvesting and restored upon re-seeding. Using semi-quantitative PCR, in the present work we find that (i) Cells do not "wait" for the normal recycling of membrane proteins to restore their lost channels, but trigger their replacement, suggesting that the membrane has a way of engaging the nucleus. (ii) Replacement channels do not come from an internal reservoir, as it is the case with Na(+), K(+)-ATPase, but requires a de novo synthesis. (iii) Replacement is not an all-or-none response, since mRNA for MaxiK channels increases by 8-fold after re-seeding, but those for Kv1.6 and Kv1.7 are not affected by harvesting/re-seeding. (iv) TEA, charybdotoxin and iberiotoxin fail to trigger the replacement response in mature monolayers, suggesting that replacement is not due to suppression of channel function. (v) MDCK cells have a typical transporting epithelial phenotype (TEP) consisting of tight junctions (TJs) plus polarity. Although the polarized distribution of K-channels is a prominent attribute of TEP, blocking their function does not perturb the development of TEP, as gauged through the development of TJs, nor level of expression (Western blot) and distribution (confocal microscopy) of occludin, and claudins 1, 3 and 7.