The physiological role and characterization of melanin produced by Shewanella algae BrY

Shewanella algae BrY is a Gram negative, facultative anaerobe isolated from the Great Bay Estuary of New Hampshire. This member of the gamma Proteobacteria demonstrates extensive versatility in the variety of terminal electron acceptors it uses for anaerobic respiration. Since the natural habitat of this non-fermenting organism is the oxiclanoxic interface of sediments, the ability to utilize various terminal electron acceptors contributes to its survival and growth. Among the terminal electron acceptors used by S. algae BrY are insoluble iron minerals. The transfer of electrons from a bacterial cell to an insoluble compound presents a strategic challenge for this organism. This dissertation focuses on understanding the mechanism of electron transfer from S. algae BrY to insoluble iron minerals and characterizing the component used in bacterial-mineral electron transfer. Here I show that S. algae BrY produces the quinone rich heteropolymer, melanin, when grown with tyrosine. The redox-cycling capabilities of melanin provide it with the ability to serve as a terminal electron acceptor and soluble electron shuttle for iron mineral reduction. When melanin is associated with the cell surface, it accelerates the rate of electron transfer from the cell membrane to iron minerals

A Current Analysis of Black Head Football Coaches and Offensive Coordinators at the NCAA DI-FBS Level

At the start of the 2015 college football season, 15 of the 128 NCAA DI-FBS programs took the field with a new head coach. Of note, is that none of the newly hired head coaches were Black, and 11 of the 15 hires climbed the coaching ranks on the offensive side of the ball. Given that 11.7% of the head coaching jobs in the league were available this offseason and none were filled by a Black coaching candidate could signify that the positive trends found after the 2010 season regarding the hiring of Black head football coaches (Bopp & Sagas, 2012) may have plateaued, or even worse, declined. The purpose of this study was to ascertain if significant strides are being made in the promotion of Black coaches to head coach and offensive coordinator positions in college football, and evaluate how successful they have been in those positions. The findings of our study, which were interpreted using racial tasking (Bopp & Sagas, 2014) as our theoretical lens, found that a) Black representation at the head coach and offensive coordinator position has plateaued, b) White head coaches statistically have higher winning percentages than their Black counterparts, c) White head coaches are afforded nearly a year more on average than Black head coaches to lead their programs, and d) that White offensive coordinators tend to manage more prolific passing teams (e.g., attempts, yards, and touchdowns) than their Black counterparts. The performance of Black coaches compared with their White counterparts has not favored Black coaches which may create prejudice in the mind of athletic administrators. Implications and suggestions for change are discussed

Welcome to America! How can athletic departments better assist international student-athletes with their transition into the American university setting?

The current study examined how athletic stakeholders (e.g., coaches and support staff) at a NCAA Division I mid-major university attempt to assist international student-athletes (ISAs) with their transition into the American university setting. Semi-structured interviews with 10 athletic administrators and coaches discussed common transition issues ISAs typically encounter (e.g., cultural changes, dietary/nutritional adjustments, financial misunderstandings, homesickness, etc.), as well as resources (e.g., consistent on-boarding checklists) and a training (e.g., cultural competency training) that should be provided to practitioners that assist/coach ISAs. Additionally, programmatic offerings that might provide support systems and improve the student-athlete experience for ISAs were discussed. Our findings highlight the considerations that athletic administrators and coaches should know when attempting to support ISAs during the beginning stages of their transition to America. Due to the growing number of ISAs competing in college sport, understanding how best to support this population is crucial for athletic departments that are hoping to attract and retain ISAs

Dimple Generators of Longitudinal Vortex Structures

Visual research of characteristic features and measurement of velocity and pressure fields of a vortex flow inside and nearby of a pair of the oval dimples on hydraulically smooth flat plate are conducted. It is established that depending on the flow regime inside the oval dimples, potential and vortex flows with ejection of vortex structures outside of dimples in the boundary layer are formed. In the conditions of a laminar flow, a vortex motion inside dimples is not observed. With an increase of flow velocity in dimples, boundary layer separation, shear layer, and potential and circulating flows are formed inside the oval dimples. In the conditions of the turbulent flow, the potential motion disappears, and intensive vortex motion is formed. The profiles of longitudinal velocity and the dynamic and wall-pressure fluctuations are studied inside and on the streamlined surface of the pair of oval dimples. The maximum wall-pressure fluctuation levels are pointed out on the aft walls of the dimples. The tonal components corresponding to oscillation frequencies of vortical flow inside the dimples and ejection frequencies of the large-scale vortical structures outside the dimples are observed in velocity and pressure fluctuation spectra

Navigating the Intersection of COVID-19 and (Re)new(ed) Calls for Racial Justice: A Qualitative Examination of the Experiences of Diversity, Equity, and Inclusion Professionals in College Athletics During A Year of “Social Justice Awakening”

The purpose of this qualitative study was to examine the experiences of diversity, equity, and inclusion (DEI) professionals in the NCAA athletics governance structure. The specific focus was centered on the multiple crises of summer 2020, including both the COVID-19 pandemic and calls for social injustices and its effects on DEI work and the impacts on DEI professionals within college athletics. In total, 23 semi-structured interviews were completed with the DEI professionals, with five major themes emerging from the results, including: (1) Reorganization of Priorities, (2) Reactive vs. Proactive Work, (3) Challenges of Virtual DEI Engagement, (4) Emotional Fatigue, and (5) Validation of DEI work. The implications for future research and practitioners will be further explored

Review of Concrete Biodeterioration in Relation to Buried Nuclear Waste

Long-term storage of low level radioactive material in below ground concrete disposal units (DUs) (Saltstone Disposal Facility) is a means of depositing wastes generated from nuclear operations of the U.S. Department of Energy. Based on the currently modeled degradation mechanisms, possible microbial induced effects on the structural integrity of buried low level wastes must be addressed. Previous international efforts related to microbial impacts on concrete structures that house low level radioactive waste showed that microbial activity can play a significant role in the process of concrete degradation and ultimately structural deterioration. This literature review examines the recent research in this field and is focused on specific parameters that are applicable to modeling and prediction of the fate of concrete vaults housing stored wastes and the wastes themselves. Rates of concrete biodegradation vary with the environmental conditions, illustrating a need to understand the bioavailability of key compounds involved in microbial activity. Specific parameters require pH and osmotic pressure to be within a certain range to allow for microbial growth as well as the availability and abundance of energy sources like components involved in sulfur, iron and nitrogen oxidation. Carbon flow and availability are also factors to consider in predicting concrete biodegradation. The results of this review suggest that microbial activity in Saltstone, (grouted low level radioactive waste) is unlikely due to very high pH and osmotic pressure. Biodegradation of the concrete vaults housing the radioactive waste however, is a possibility. The rate and degree of concrete biodegradation is dependent on numerous physical, chemical and biological parameters. Results from this review point to parameters to focus on for modeling activities and also, possible options for mitigation that would minimize concrete biodegradation. In addition, key chemical components that drive microbial activity on concrete surfaces are discussed

Are You Welcomed? A Racial and Ethnic Comparison of Perceived Welcomeness in Sport Participation

International Journal of Exercise Science 10(6): 833-844, 2017. Sport has become racialized such that minority youth accrue limited health and academic benefits from participation, compared to their White counterparts. Understanding the welcomeness that minorities feel in sport, leisure and physical activities plays an important role in breaking down barriers to participation. Thus, the overall aim of this study is to further examine the determinants of sport participation, particularly as it relates to race, socialization and perceived welcomeness. College students (N = 451) scored their perceived level of welcomeness for Whites, African Americans and Hispanic/Latinos in 14 sports. Results reveal significant differences in the perceived welcomeness felt by Whites, African Americans and Hispanic/Latinos in most of the sports analyzed. The discussion focuses on the socialization agents that facilitate such racialized perceptions and hinder access and opportunities for racial and ethnic minority youth to experience the health, academic and social benefits of sport participation

THE ROLE OF 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE IN ENHANCEMENT OF SOLID-PHASE ELECTRON TRANSFER BY SHEWANELLA ONEIDENSIS MR-1

While mechanistic details of dissimilatory metal reduction are far from being understood, it is postulated that the electron transfer to solid metal oxides is mediated by outer membrane-associated c-type cytochromes and redox active electron shuttling compounds. This study focuses on the production of homogensitate in Shewanella oneidensis MR-1, an intermediate of tyrosine degradation pathway, which is a precursor of a redox cycling metabolite, pyomelanin. In this study, we determined that two enzymes involved in this pathway, 4-hydroxyphenylpyruvate dioxygenase (4HPPD) and homogentisate 1,2-dioxygenase are responsible for homogentisate production and oxidation, respectively. Inhibition of 4-HPPD activity with the specific inhibitor sulcotrione (2-(2-chloro-4-methane sulfonylbenzoyl)-1,3-cyclohexanedione), and deletion of melA, a gene encoding 4-HPPD, resulted in no pyomelanin production by S. oneidensis MR-1. Conversely, deletion of hmgA which encodes the putative homogentisate 1,2-dioxygenase, resulted in pyomelanin overproduction. The efficiency and rates, with which MR-1 reduces hydrous ferric oxide, were directly linked to the ability of mutant strains to produce pyomelanin. Electrochemical studies with whole cells demonstrated that pyomelanin substantially increases the formal potential (E{sup o}{prime}) of S. oneidensis MR-1. Based on this work, environmental production of pyomelanin likely contributes to an increased solid-phase metal reduction capacity in Shewanella oneidensis