Plain Language Abstracts

Original Abstract 

Plain Language Abstract 

This study used path analyses to test a theoretical model of influences on the quality of life for stroke caregivers at one and six months post stroke. The purpose of this study was to identify predictors of quality of life in stroke caregivers at one and six months post stroke. This study also examined ethnic differences in the caregiving trajectory and the influence of the time spent with the care recipient on the quality of life outcomes for stroke caregivers.

Patient and caregiver characteristics had some influence directly on the quality of life outcomes for stroke caregivers. However, the most influential factor on each quality of life dimension was the sense of coherence. Sense of coherence is the ability of caregivers to mobilize their coping resources during periods of distress. Caregivers who were able to do this effectively experienced less burden in four dimensions and less depression.

Ethnic differences were present in quality of life outcomes for stroke caregivers. Hispanic caregivers were more likely to spend time in the caregiving role, and experience more negative consequences in their lives as a result of providing care. African-American caregivers appear to experience more burden and depression initially, but this diminished by six months. Interestingly but not significantly, Caucasians and Hispanics were most similar in their quality of life outcomes, whereas African Americans appeared to experience different patterns over time in their quality of life.

People who provide unpaid care for a family member or friend are known as informal caregivers. Informal caregivers’ quality of life can be positively and negatively influenced by providing care. This study surveyed 127 informal caregivers of stroke survivors and was particularly interested in factors that predicted quality of life for the caregivers at one and six months following the stroke. We found that caregivers who could use several different types of ways to deal with stress felt less burden and depression. Caregivers who were Hispanic spent more time providing care and experienced more negative quality of life.

Original Abstract 

Plain Language Abstract 

The subject of this thesis is the impact of electrostatic properties on a protein’s fold specificity and stability. In chapter 2, we describe the development and parameterization of a generalized Born implicit solvation model for proteins and nucleic acids. We demonstrate that our parameterization can rapidly and accurately reproduce electrostatic solvation energies and forces obtained from the more rigorous Poisson model at greatly enhanced speed. In chapter 3, we use the generalized Bom model in conjunction with the CHARMM polar hydrogen force field to explore the role of various energy terms in determining protein fold specificity. The physics-based force field is shown to be as good or better at identifying native folds than knowledge-based force fields trained to perform this function. In chapter 4, we explore the role of electrostatics in stabilizing the protein’s native fold over the ensemble of unfolded states. In particular, we target thermophilic and hyperthermophilic proteins in an attempt to rationalize the observed correlation between surface salt bridge interactions and thermostability. We find that an enhanced dielectric response in thermophilic proteins substantially reduces the desolvation penalty associated 1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. with charged sidechains and the process of protein folding. As a result, direct Coulomb attraction can potentially dominate this desolvation penalty leading to electrostatic stabilization of the native conformation. Finally, in chapter 5, we continue our exploration of electrostatic properties of thermophilic proteins by examining the role of salt on the stability of these systems. We examine a family of cold shock proteins derived from mesophilic, thermophilic, and hyperthermophilic organisms. Our model for determining the effects of salt on protein stability is shown to be in excellent agreement with experimental studies performed in parallel through a collaboration with Dieter Perl and Dr. Franz Schmid. From this understanding, we are able to predict the effect of any point mutation on the salt dependent stability in many protein systems. Further, we are able to demonstrate that designed mutants exhibit electrostatic properties consistent with thermophilic species. The work described in this thesis demonstrates the significant roles of electrostatic properties in protein fold specificity, stability, and function

Within our bodies, large molecules called proteins are working to support virtually every process that sustains our lives. Such processes include converting food into useful energy, repairing wounds and fighting off disease, pumping blood through our arteries and veins, and also sensing and adapting to the changing world around us. Proteins perform similarly important tasks in disease-causing bacteria and viruses, making these proteins important targets for a very large number of medicines. Understanding our bodies and how to keep them healthy means understanding proteins and how they work. Research conducted over the past 100 years has demonstrated that each protein must ‘fold’ into a specific shape for it to function. Different proteins will fold into different shapes, and this folding is necessary for the proteins to function. While we understand WHY proteins fold into specific shapes, HOW proteins fold has been a difficult question to answer.

My doctoral dissertation describes the development and testing of equations, based in physics, that help explain HOW proteins fold into the shapes that they do. Using these equations, I was able to explain how proteins and their associated organisms can function at near boiling temperatures, in extremely salty environments, and below freezing conditions. I also used these equations to understand how small changes in the shape of proteins from viruses can reduce the effectiveness of some medicines. Small changes in the shape of proteins is one way in which disease-causing viruses may become ‘drug-resistant’, or no longer treatable using available medicines. This research represented the starting point for creating new medicines that would be less sensitive to these small changes in protein shape and reduce the possibility of drug resistance.

Plain Language Abstract

Most college faculties have three professor ranks. The highest rank is Full Professor. About 1% of Full Professors in the U.S. are Black women. There is not much research about what it is like to be promoted to full professor, especially for Black women.

I studied Black women's perceptions of how racism and sexism affected their promotion experiences. I also studied the impact of promotion on their professional status and influence in their departments, institutions, and fields of study.

Findings showed that racism and sexism created three effects.

1. Institutions applied promotion policies and procedures inconsistently.
2. Black women who aspired to promotions were perceived as arrogant.
3. Even when Black women were promoted to Full Professors, their merits were minimized or dismissed, limiting their influence.

This study suggests that colleges and universities need to examine their promotion practices and policies. This review may uncover issues limiting Black women's access to the rank of full professor and that rank's many benefits.

Plain Language Abstract

All living organisms have DNA with genes that are responsible for how we look, behave, and react to changes in our environment.  Genes can be turned on or turned off when a cell or an organism experiences a change in its environment.  The ability to control genes requires a piece of DNA adjacent to the gene called a promoter.  Bacteria have genes that allow them to manufacture certain nutrients when they are missing in their food.  Bacteria organize genes for a common purpose such as making nutrients into a linear string (called an operon) that is controlled by a single promoter next to the first gene in the operon.  My research sought to determine if bacteria can control subsets of the genes in the operon using additional promoters and if this arrangement was unique to one type of bacteria.  My research involved searching for the presence of promoters adjacent to other genes within the operon.  I found two promoters within an operon.  One was adjacent to the third gene in the operon and the other was adjacent to the fifth and final gene in the operon.  I also found that these two new promoters functioned in two different bacteria.  The promoter next to the third gene played a much more important role in one of the two bacteria and the promoter next to the last gene responded to oxygen levels rather than the absence of the nutrient in the food.  My research has three large implications.  In order to truly understand how genes are controlled we now know that we will have to search for promoters in new locations.  Second, we will now have access to a whole new set of promoters that can be engineered to produce important biological products.  Lastly, we now have an additional clue to how genes function I the identity and behavior of an organism.