(1) The Relationship of Protein Expression and Cell Division, (2) 3D Imaging of Cells Using Digital Holography, and (3) General Chemistry Enrollment at University of Michigan.

Abstract

Chapter 1: We evaluated the relationship between cell division and protein expression when using commercial poly(ethylenimine) (PEI)-based polyplexes. The membrane dye PKH26 was used to assess cell division, and cyan fluorescent protein (CFP) was used to monitor protein expression. When analyzed at the whole population level, a greater number of cells divided than expressed protein, regardless of the level of protein expression observed, giving apparent consistency with the hypothesis that protein expression requires cells to pass through mitosis in order for the transgene to overcome the nuclear membrane. However, when the polyplex-exposed population was evaluated for the amount of division in the protein-expressing subpopulation, it was observed that substantial amounts of expression had occurred in the absence of division.

Chapter 2: We monitored cell volume changes in real time during apoptosis using digital holographic microscopy (DHM). The results showed that after exposure to 1 μM staurosporine for four hours, the volumes of KB cells were reduced by ~50-60%, which is consistent with previous results obtained using electronic cell sizing and atomic force microscopy. In comparison with other techniques, DHM is advantageous because it employs noninvasive detection, has high time resolution and real time measurement capability, and can simultaneously probe the time-dependent volume changes of individual cells and cell populations.

Chapter 3: We examined the impact of concurrent versus nonconcurrent enrollment on 9,438 students’ withdrawal rates from and final grades in the general chemistry lecture at the University of Michigan at Ann Arbor using multiple linear and binary logistic regression analyses, respectively, at a significance level of 0.05. We found that concurrent enrollment in the lecture and laboratory positively impacts (1) the odds of retention in the lecture by a factor of 2.2 times on average and (2) the final grades in the lecture course by up to 0.19 grade points on a 4.0 scale for the students that scored the lowest on university-level mathematics and chemistry placement exams.