Dynamic Surface Activity by Folding and Unfolding an Amphiphilic α-Helix

We describe a rationally designed peptide with tunable surface activity, where the dynamics of surface activity are an outcome of helical folding. Our rationally designed model peptide is surface-active only as an α-helix. We apply circular dichroism to show that the folded population can be controlled with changes in electrolyte concentration, and we apply pendant bubble tensiometry to explore dynamic surfactant activity. This study shows a peptide that responds to environmental stimuli with dynamic folding and surface activity. Extending this concept to selective binding peptides will lead to new tools, where dynamic surface activity is coupled to targeted binding

Alternatives to the Current AASHTO Standard Bridge Sections

The main objective of this study was evaluate feasible alternatives to the current AASHTO bridge girders used in Indiana. This evaluation included precast pretensioned bridge girders for spans from 30 to 130 feet with girder spacing between 5 and 10 feet up to 12 feet for the longer spans. Other criteria included girder design concrete compressive strengths up to 7000 psi, 8” total concrete deck thickness with design strength of 4000 psi, grade 60 steel for slab reinforcement and stirrups and ½” special grade 270 low-relaxation strand for prestressing steel. Post-tensioning and pretensioned box girders were outside the scope of the study. Approximately 100 alternate sections were received from surveys sent to various department of transportation, consultants, and precasters in the United States. The girder cross sections were then evaluated for their structural efficiency and c ost effectiveness. This was done using the computer program, PCBM, developed by Professor Robert H. Lee at Purdue University and currently used by INDOT. The AASHTO I, II, and III girders were found to be economical for spans 30 to 70 feet. No alternate sections were therefore recommended in this span range. In the range from 70 to 90 feet the Illinois 54” section is considered the most economical. This section is currently being used as the only alternate section in Indiana. Other alternate sections were found to be more economical for spans over 90 feet. The Kentucky Bulb Tees were recommended for use in spans from 90 to 130 feet to provide considerable savings over the standard AASHTO girders. This would result in a savings of as much as 20 to 25 percent of the bridge superstructure for the longer spans. Design Aids were created fro these Kentucky Bulb Tees as well as for the AASHTO standards and the Illinois 54” sections. The use of these sections is supported by this research study and recommended to INDOT. Adopting these alternate sections would result in considerable savings in Indiana’s bridge construction

Subconjunctival Carboplatin Therapy and Cryotherapy in the Treatment of Transgenic Murine Retinoblastoma

OBJECTIVES: To determine the efficacy and dose response of subconjunctival carboplatin with and without cryotherapy in the treatment of murine transgenic hereditary retinoblastoma. METHODS: Fifty-one 5-week-old transgenic BLH SV-40 (Charles Rivers Laboratories, Boston, Mass) T-antigen-positive mice with retinoblastoma were administered 6 subconjunctival injections of carboplatin in 1 eye at drug doses of 10, 15, 20, 25, 62.5, 125, and 250 μg. Six control eyes received 6 subconjunctival injections of balanced salt solution. Fourteen of the 51 subconjunctivally treated eyes received a single application of transconjunctival cryotherapy immediately prior to each carboplatin injection. Six control eyes received 6 single applications of transconjunctival cryotherapy using the above schedule but did not receive carboplatin. All experimental and control eyes were obtained at 16 weeks of age for histopathologic examination. RESULTS: A dose-dependent inhibition of intraocular tumor growth by subconjunctivally delivered carboplatin was observed in these transgenic retinoblastoma mice. Tumor development was inhibited in 50% of the mouse eyes at doses of 180 μg. In animals treated with cryotherapy alone, no tumor control was noted (0 of 6). In animals treated with subconjunctival carboplatin coupled with cryotherapy, a tumor control dose of 417 pg was found. No evidence of histopathologic treatment toxicity was noted. CONCLUSIONS: Subconjunctival delivery of carboplatin in serial doses effectively inhibits intraocular tumor growth in a dose-dependent fashion in a transgenic murine retinoblastoma model. Cryotherapy does not increase tumor control in this murine retinoblastoma model