INTRODUCTION In this article we describe an honors course titled "Paths to Knowledge," ... more INTRODUCTION In this article we describe an honors course titled "Paths to Knowledge," which was created to provide students with an understanding of the ways different disciplines create and evaluate knowledge. This is the only specific course within our honors curriculum that is required of all honors students. After seeing it evolve over several years, multiple instructors, and a variety of approaches to the theme, we believe that Paths to Knowledge may be a good model for a foundational course within an honors program. INSTITUTIONAL, NATIONAL, AND HISTORICAL CONTEXT At Drake University, students can complete the general education requirements via two distinct routes: 1) the Drake curriculum or 2) the honors curriculum. The vast majority of students opt for the standard Drake curriculum, which resembles traditional general education programs in its requirement that students complete one or two courses within disciplines/areas of inquiry. The honors curriculum, in contra...
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2007
Here we present a fluorescence method based on the Stokes shift of the voltage-sensitive dye di-8... more Here we present a fluorescence method based on the Stokes shift of the voltage-sensitive dye di-8-ANEPPS to quantify the orientational polarisability of lipid membrane surfaces, i.e. the polarisability due to molecular reorientation. Di-8-ANEPPS is already an established probe of membrane dipole potential. Its use, therefore, as a probe of both the dipole potential and orientational polarisability allows a direct comparison of these two properties in an identical region of the lipid bilayer. We applied the new technique on phosphatidylcholine vesicles to study the effects of different degrees of hydrocarbon saturation and of the incorporation of cholesterol and some of its oxidized derivatives. We found that lipids with unsaturated chains had a lower orientational polarisability than those with saturated chains. This could be explained by a reduction in membrane dipole potential as a result of a decrease in lipid packing density. Cholesterol derivatives were found to either increase or decrease the orientational polarisability depending on their molecular structure. The varying effects could be explained by antagonistic effects of the dipole potential and membrane order, which are both changed to varying degrees by the cholesterol derivatives and which lead to increases and decreases in orientational polarisability, respectively.
INTRODUCTION In this article we describe an honors course titled "Paths to Knowledge," ... more INTRODUCTION In this article we describe an honors course titled "Paths to Knowledge," which was created to provide students with an understanding of the ways different disciplines create and evaluate knowledge. This is the only specific course within our honors curriculum that is required of all honors students. After seeing it evolve over several years, multiple instructors, and a variety of approaches to the theme, we believe that Paths to Knowledge may be a good model for a foundational course within an honors program. INSTITUTIONAL, NATIONAL, AND HISTORICAL CONTEXT At Drake University, students can complete the general education requirements via two distinct routes: 1) the Drake curriculum or 2) the honors curriculum. The vast majority of students opt for the standard Drake curriculum, which resembles traditional general education programs in its requirement that students complete one or two courses within disciplines/areas of inquiry. The honors curriculum, in contra...
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2007
Here we present a fluorescence method based on the Stokes shift of the voltage-sensitive dye di-8... more Here we present a fluorescence method based on the Stokes shift of the voltage-sensitive dye di-8-ANEPPS to quantify the orientational polarisability of lipid membrane surfaces, i.e. the polarisability due to molecular reorientation. Di-8-ANEPPS is already an established probe of membrane dipole potential. Its use, therefore, as a probe of both the dipole potential and orientational polarisability allows a direct comparison of these two properties in an identical region of the lipid bilayer. We applied the new technique on phosphatidylcholine vesicles to study the effects of different degrees of hydrocarbon saturation and of the incorporation of cholesterol and some of its oxidized derivatives. We found that lipids with unsaturated chains had a lower orientational polarisability than those with saturated chains. This could be explained by a reduction in membrane dipole potential as a result of a decrease in lipid packing density. Cholesterol derivatives were found to either increase or decrease the orientational polarisability depending on their molecular structure. The varying effects could be explained by antagonistic effects of the dipole potential and membrane order, which are both changed to varying degrees by the cholesterol derivatives and which lead to increases and decreases in orientational polarisability, respectively.
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Papers by Mark Vitha