The Ursinus Weekly, June 12, 1908

Baccalaureate service • Class Day exercises • Commencement Day exercises • Junior oratorical contest • Alumni oration • Baseball • Literary societies • Baseball resume • Notable wedding • Evangelical conference • Charmidean banquet • Alumni luncheon • Literary Supplement: Charles Darwin; The birthday anniversary; Ulrich Zwingli: a contrast with Martin Luther; The school and the convent; The decisionhttps://digitalcommons.ursinus.edu/weekly/2912/thumbnail.jp

Integration of Isoelectric Focusing with Parallel Sodium Dodecyl Sulfate Gel Electrophoresis for Multidimensional Protein Separations in a Plastic Microfludic Network,” Anal.

An integrated protein concentration/separation system, combining non-native isoelectric focusing (IEF) with sodium dodecyl sulfate (SDS) gel electrophoresis on a polymer microfluidic chip, is reported. The system provides significant analyte concentration and extremely high resolving power for separated protein mixtures. The ability to introduce and isolate multiple separation media in a plastic microfluidic network is one of two key requirements for achieving multidimensional protein separations. The second requirement lies in the quantitative transfer of focused proteins from the first to second separation dimensions without significant loss in the resolution acquired from the first dimension. Rather than sequentially sampling protein analytes eluted from IEF, focused proteins are electrokinetically transferred into an array of orthogonal microchannels and further resolved by SDS gel electrophoresis in a parallel and high-throughput format. Resolved protein analytes are monitored using noncovalent, environment-sensitive, fluorescent probes such as Sypro Red. In comparison with covalently labeling proteins, the use of Sypro staining during electrophoretic separations not only presents a generic detection approach for the analysis of complex protein mixtures such as cell lysates but also avoids additional introduction of protein microheterogeneity as the result of labeling reaction. A comprehensive 2-D protein separation is completed in less than 10 min with an overall peak capacity of ∼1700 using a chip with planar dimensions of as small as 2 cm × 3 cm. Significant enhancement in the peak capacity can be realized by simply raising the density of microchannels in the array, thereby increasing the number of IEF fractions further analyzed in the size-based separation dimension

Phase estimation from transmitted-light DIC images using rotational diversity

Differential-Interference-Contrast (DIC) microscopy is a powerful technique for the visualization of unstained transparent specimens, thereby allowing in vivo observations. Quantitative interpretation of DIC images is difficult because the measured intensity is nonlinearly related to the gradient of a specimen's optical-path-length distribution along the shear direction. The recent development of reconstruction methods for DIC microscopy permits the calculation of a specimen's optical-path-length distribution or phase function and provides a new measurement technique for biological applications. In this paper we present a summary of our work on quantitative imaging with a DIC microscope. The focus of our efforts has been in two areas: 1, model development and testing for 3D DIC imaging; and 2, development of a phase-estimation method based on this model. Our method estimates a specimen's phase function using rotational diversity DIC images, i.e. multiple DIC images obtained by rotating t..

Determination of Direction-Independent Optical Path-Length Distribution of Cells Using Rotational-Diversity Transmitted-Light Differential Interference Contrast (DIC) Images

Two different phase-estimation methods that have been developed for the computation of the optical path-length (OPL) distribution of a specimen from DIC images are compared in this paper. The first method is based on the Wiener filter approach and uses only a single DIC image for the determination of the OPL distribution. The second phase-estimation method is based on the conjugate-gradient optimization method and estimates the OPL distribution using rotational-diversity DIC images; i.e. multiple DIC images obtained by rotating the specimen. For this study, 24 different DIC images of a single bovine spermatozoa head were acquired by rotating the cell by approximately 15 degrees between images. The images were registered and aligned using fiducial marks, and then processed with both methods. Results obtained with the filtering method were found to be dependent on the orientation of the cell with respect to the shear direction. Comparison of the integrated optical path length (IOPL) com..