Synthesis of Imidazolium Compounds as Model Substrates for Biomimetic Mono-Iron Hydrogenase Complexes

As the demand for carbon-free fuel sources has increased, hydrogen gas has become a promising alternative since it can be produced from water. However, efficient production of H2 requires the use of expensive metal catalysts such as platinum. Because of the cost and low availability of these metals, scientists have turned to nature as inspiration for the development of metal catalysts that use cheaper, more abundant transition metals. One such example of a natural H2 catalyst is the mono-iron hydrogenase enzyme, which heterolytically cleaves H2 into a proton and hydride. The active site of this enzyme contains a central iron atom surrounded by a nitrogen-bound pyridone, an acyl carbon, and a cysteine thiolate donor. This unique arrangement of ligands allows the enzyme to activate H2 with the help of the substrate, methenyl-H4MPT+. Previous research by the Rose Group has led to the development of a functional biomimetic model of the mono-Fe hydrogenase active site that is capable of activating H2. This biomimetic model can accept a hydride from the substrate, but the reverse reaction of hydride transfer to the substrate had yet to be observed. To achieve this, obtaining more information about the role of the substrate in H2 activation was necessary. This research therefore focused on the synthesis of a model imidazolium substrate based on methenyl- H4MPT+. In reactivity studies with an enzyme model, it was determined that altering the Lewis acidity of the model substrate promoted hydride transfer from the model complex. With this insight, it is hoped that the interaction between the endogenous substrate and the mono-iron hydrogenase active site can be better understood.Chemistr

From washing to whitening: the cosmetic practices and beauty politics of Vietnamese-American women in Boston

Thesis (M.A.)--Boston UniversityThis thesis examines perceptions of normative beauty ideals among Vietnamese-American women and the impact of these ideals on beauty seeking behaviors. I explore women’s lived experience of beauty via practices pursued and products consumed, and frame beauty work as a disciplinary practice, as well as an investment in embodied species of capital. I query how ideals of appearance relate to being Vietnamese within American culture and the critical role of appearance in affirming identity. The methods used were in-depth interviews (n=5), an open-ended response Internet survey (n=19), and a content analysis of a transnational Pond's advertisement to which both Internet participants and in-depth interview participants contributed

Tactical adjustment of signaling leads to increased mating success and survival

Most sexually reproducing animals overcome the challenge of searching for and attracting mates by utilizing signals that are broadcast through a spatially and temporally varying environment. A diverse suite of behavioral solutions exist for overcoming such environmental variability, including the adjustment of signaling behavior based upon receiver feedback. Few studies have directly examined the relationship between such tactical signaling adjustments and proxies of male fitness; the few that have, failed to find a relationship. Using the wolf spider, Schizocosa rovneri, we set out to first quantify among-male variation in the form and degree of responsiveness to female feedback. Following exposure to female receptivity cues, some males increased their signaling on an effective signaling substrate (filter paper) while others decreased signaling on the effective substrate. These groups of males were then run through mating trials, conducted in a heterogeneous environment, to examine the relationship between male signaling adjustments and subsequent mating success. Males that adaptively adjusted their signaling (i.e. increased signaling on a more effective substrate) were (1) more likely to copulate, (2) achieved a copulation more quickly and (3) were less likely to be attacked; thus establishing a positive relationship between tactical adjustments of courtship signaling and male fitness

Tactical adjustment of signaling leads to increased mating success and survival

Most sexually reproducing animals overcome the challenge of searching for and attracting mates by utilizing signals that are broadcast through a spatially and temporally varying environment. A diverse suite of behavioral solutions exist for overcoming such environmental variability, including the adjustment of signaling behavior based upon receiver feedback. Few studies have directly examined the relationship between such tactical signaling adjustments and proxies of male fitness; the few that have, failed to find a relationship. Using the wolf spider, Schizocosa rovneri, we set out to first quantify among-male variation in the form and degree of responsiveness to female feedback. Following exposure to female receptivity cues, some males increased their signaling on an effective signaling substrate (filter paper) while others decreased signaling on the effective substrate. These groups of males were then run through mating trials, conducted in a heterogeneous environment, to examine the relationship between male signaling adjustments and subsequent mating success. Males that adaptively adjusted their signaling (i.e. increased signaling on a more effective substrate) were (1) more likely to copulate, (2) achieved a copulation more quickly and (3) were less likely to be attacked; thus establishing a positive relationship between tactical adjustments of courtship signaling and male fitness

Effects of a Physical Education Supportive Curriculum and Technological Devices on Physical Activity

The purpose of this study was to examine the effects of a physical education supportive curriculum and technological devices, heart rate monitor (HRM) and pedometer (PED), on physical activity. A single-subject ABAB research design was used to examine amount and level of participation in physical activity among 106 suburban fourth and fifth graders during physical education class. A curriculum, which was pedagogically centered on the use of the technological devices, was also developed and studied. Six children from each group and the physical education teacher were interviewed. The results of a one-way ANCOVA indicated group differences between the supportive curriculum and technology for HRMs, PEDs, and increased physical activity

Las leyes de información en México y en los Estados Unidos: estudio comparado

Tesis (Maestría en Derecho Público) U.A.N.L.UANLhttp://www.uanl.mx

IMPACT: The Journal of the Center for Interdisciplinary Teaching and Learning. Volume 9, Issue 1, Winter 2020

Explicitly established to foreground interdisciplinary teaching and learning, Impact also welcomes evidence and discussion of experiential learning. Often the two – interdisciplinary teaching and experiential learning – co-exist. Yet even when they do not, both practices model how to think in myriad ways and to notice how knowledge is constructed. As our winter 2019 issue makes clear, interdisciplinary teaching and learning and experiential learning often begin with questions. Why does it matter that students grapple directly with archival material? What happens when undergraduates practice psychology by training dogs? Do students understand financial literacy? This issue also asks questions about students’ reading habits and faculty expectations of them as readers

The complexities of female mate choice and male polymorphisms: Elucidating the role of genetics, age, and mate-choice copying

Genetic, life history, and environmental factors dictate patterns of variation in sexual traits within and across populations, and thus the action and outcome of sexual selection. This study explores patterns of inheritance, diet, age, and mate-choice copying on the expression of male sexual signals and associated female mate choice in a phenotypically diverse group of Schizocosa wolf spiders. Focal spiders exhibit one of two male phenotypes: ‘ornamented’ males possess large black brushes on their forelegs, and ‘non-ornamented’ males possess no brushes. Using a quantitative genetics breeding design in a mixed population of ornamented/non-ornamented males, we found a strong genetic basis to male phenotype and female choice. We also found that some ornamented males produced some sons with large brushes and others with barely visible brushes. Results of diet manipulations and behavioral mating trials showed no influence of diet on male phenotype or female mate choice. Age post maturation, however, influenced mate choice, with younger females being more likely to mate with ornamented males. A mate-choice copying experiment found that, following observations of another female’s mate choice/copulation, virgin mature females tended to match the mate choice (ornamented vs. non-ornamented males) of the females they observed. Finally, analyses of genetic variation across phenotypically pure (only one male phenotype present) vs. mixed (both phenotypes present) populations revealed genetic distinction between phenotypes in phenotypically-pure populations, but no distinction in phenotypically-mixed populations. The difference in patterns of genetic differentiation and mating across geographic locations suggests a complex network of factors contributing to the outcome of sexual selection

The complexities of female mate choice and male polymorphisms: Elucidating the role of genetics, age, and mate-choice copying

Genetic, life history, and environmental factors dictate patterns of variation in sexual traits within and across populations, and thus the action and outcome of sexual selection. This study explores patterns of inheritance, diet, age, and mate-choice copying on the expression of male sexual signals and associated female mate choice in a phenotypically diverse group of Schizocosa wolf spiders. Focal spiders exhibit one of two male phenotypes: ‘ornamented’ males possess large black brushes on their forelegs, and ‘non-ornamented’ males possess no brushes. Using a quantitative genetics breeding design in a mixed population of ornamented/non-ornamented males, we found a strong genetic basis to male phenotype and female choice. We also found that some ornamented males produced some sons with large brushes and others with barely visible brushes. Results of diet manipulations and behavioral mating trials showed no influence of diet on male phenotype or female mate choice. Age post maturation, however, influenced mate choice, with younger females being more likely to mate with ornamented males. A mate-choice copying experiment found that, following observations of another female’s mate choice/copulation, virgin mature females tended to match the mate choice (ornamented vs. non-ornamented males) of the females they observed. Finally, analyses of genetic variation across phenotypically pure (only one male phenotype present) vs. mixed (both phenotypes present) populations revealed genetic distinction between phenotypes in phenotypically-pure populations, but no distinction in phenotypically-mixed populations. The difference in patterns of genetic differentiation and mating across geographic locations suggests a complex network of factors contributing to the outcome of sexual selection