The Exploration of Small Molecules, Lanthanide Complexes, and Catalysis using Electronic Structure Theory, Dynamics, and Machine Learning

With the ever increasing availability of computational resources, more challenging chemical systems can be studied. Among these challenges are the rotational and vibrational spectra of diatomic molecules within spectroscopic accuracy, the environmental perturbations induced on a rotating water molecule, the prediction of free binding energies of lanthanide complexes using machine learning, and the study of catalytic mechanisms through a theoretical framework. High levels of electronic structure theory were combined with a rigorous treatment of either the anharmonic vibrational wave functions to study diatomic molecules or the rotational wave functions to study H2O-pH2 interactions. The former was initially applied to the CF+ cation and excellent agreement was observed between theoretical and experimental spectroscopic constants. Likewise, the H2O-pH2 interactions were utilized to identify satellite peaks in the infrared spectra of a H2O-doped, pH2 crystal lattice. These peaks most likely occur due to a vacancy site directly around the H2O molecule. The study of lanthanide complexes is challenging due to their unique electronic structure. Specifically, the study of lanthanide-tris-β-diketone complexes was studied to calculate their respective free binding energies. Machine learning was utilized in this instance to act as the function which mapped the structure of the β-diketone ligands to the free binding energies. Predictions were made and several β-diketone ligands were identified which maximized the separation between lanthanide and lutetium. Finally, the study of catalytic mechanisms using theoretical methods is not without challenge due to the complex electronic structure of such systems. The hydrogen evolution reaction, the dehalogenation of CH2Cl2, the hydrogenation of small, unsaturated hydrocarbons, and the hydroformylation reaction were studied using either molecular electrocatalysts or transmetalated forms of the HKUST-1 metal-organic framework

Exploring Domain-Specific Perfectionism: Do Excelling Student-Athletes Differ in Perfectionism than their Teammates?

Perfectionism can be defined as striving for perfection and setting excessively high standards along with tendencies of hypercritical evaluation of behaviors (Frost, Marten, Lahart, & Rosenblate, 1990). Recent research suggested that perfectionism might differ between domains (e.g., academics, athletics). For example, Dunn, Dunn, and McDonald (2012) showed that student-athletes perceived higher perfectionistic tendencies in athletics compared to academics. However, it is unknown whether there were differences between excelling athletes (e.g., All-Americans) and their teammates. As such, the purpose of the present study was two-fold: a) to examine the differences between excelling athletes (i.e., qualifying for Academic All-American) and their teammates, and b) to explore predictors of perfectionism in academics and athletics. In total, 199 NCAA athletes (female n = 106, Mage = 19.49, SDage = 1.19; male n = 91, Mage = 19.35, SDage = 1.17) completed domain-specific (i.e., academics and athletics) measures of perfectionism, intolerance of uncertainty, perceptions of competence and importance, satisfaction, and stress. Fifty-eight participants met the criteria for Academic All-american (i.e., GPA \u3e 3.3, starting status) and were considered as ‘excelling’. To compare excelling student athletes to their teammates, three mixed-model ANOVAs were conducted. Athletes in both groups generally showed significantly higher perceptions of perfectionism in athletics compared to academics on all dimensions. For the second purpose of the study, six multiple regressions predicting perfectionism in both domains were conducted. Prospective intolerance of uncertainty was the strongest predictor in all six regressions

‘Poor Hockey Behaviors’: Athletes’ Moral Acculturation Experiences In Youth Hockey

Competitive youth sport requires athletes to persistently decide what the moral course of action is across situation (Boardley, 2020; Rest, 1984). Sport cultures that contain coaches who endorse a win at all cost mentality encourage athletes’ engagement in behaviors that are detrimental to their opponents to achieve competitive success (Boardley & Kavussanu, 2007). Bandura (1991) proposed that environmental processes can alter how an individual determines the moral course of action through the anticipation of behavior to produce self-referenced positive consequences, such as pride or satisfaction. The purpose of this study was to explore athletes’ moral acculturation experiences within hockey culture as illuminated in theoretical contentions of moral thinking and agency. A qualitative methodology was employed through the implementation of stimulated recall interviews (SRIs) to examine Tier I Varsity male hockey athletes’ (N = 4; Mage = 16.5 years), acculturation experiences relevant to their engagement in at least two PHBs. An iterative reflexive thematic analysis (RTA) indicated the emergence of four themes relevant to how participants’ acculturation experiences were used to regulate their engagement in PHBs: (a) Immediate Who, (b) Extended Who, (c) Give to Get, and (d) All in Together or Out all Alone. In addition, multiple sub-themes emerged to reflect how participants’ developed expectations of their PHBs to produce negative consequences for their opponent and/or opponent’s team: (a) Get ‘em Scared, (b) It’s Gonna be a Long Day, and (c) Take ‘em Out of the Game. Participants’ expectations of the negative consequences for their opponent or opponent’s team were perceived as necessary antecedents to the sub-themes representative of the positive consequences participants anticipated for themselves and/or their team: (a) Fires us Up, (b) Keeps our Team Rolling, and (c) Definitely Negatively Impacts Them. Results also indicated how controlling coaching behaviors were used by athletes to anticipate their PHBs to produce positive self-referenced consequences described in the following sub-themes: (a) Get More Ice Time, (b) Be Proud, and (c) Showing Grittiness. Finally, results indicated how specific psychological mechanisms enabled athletes’ anticipation of negative consequences for their opponent and/or opponent’s team to produce positive consequences for themselves and/or their team reflected in the following sub-themes: (a) Proving You’re Better, (b) Build the Camaraderie, (c) Try to Hurt, and (d) Obviously to Win. Findings from the current study extended clarification of how controlling coaching behaviors and various psychological mechanisms are used by hockey athletes to develop expectations of their PHBs to produce self-referenced positive consequences as a function of the negative consequences for their opponent and/or opponent’s team

Muscle Oxidative Phenotype in the Progression of Cancer-Cachexia

Cancer is one of the leading causes of death across the world. Cancer-cachexia is a serious complication induced by cancer resulting in whole body muscle wasting and is responsible for up to 40% of cancer related deaths. Underlying mechanisms of cancer-cachexia are not well understood; however, a loss in oxidative metabolism in skeletal muscle is apparent in cancer-cachexia. PURPOSE: To examine oxidative phenotype of skeletal muscle in tumor bearing mice during progression of cancer-cachexia. METHODS: Mice were implanted with Lewis Lung Carcinoma (LLC) or sham phosphate buffered saline (PBS) at 8 weeks of age. The tumor was allowed to progress for four weeks, with cohorts harvested weekly. Tibialis Anterior (TA) muscle cross sections were stained for Succinate dehydrogenase (SDH) to analyze the percent of oxidative muscle fibers and cross-sectional area (CSA) of SDH positive and negative fibers was analyzed. Immunoblotting was utilized to examine markers of mitochondrial content and biogenesis, specifically peroxisome proliferator-activated receptor- γ coactivator-1α (PGC-1α) and Cytochrome c oxidase-IV (COX-IV). RESULTS: TA weight was approximately 10% lower in 4 week LLC mice when compared to PBS control mice. In the PBS group, 65% of fibers were SDH positive compared to only 40% SDH positive in 4 week LLC mice with no other differences among groups. COX-IV was significantly reduced in 4 week LLC mice compared to PBS with no other differences among groups. No significant differences in PGC-1α were observed. CONCLUSION: LLC in mice may promote a cellular energy crisis leading to a decrease in skeletal muscle oxidative phenotype. Based on my findings, promoting the oxidative phenotype and hence the mitochondrial network could be a potential therapeutic target to treat cancer-cachexia

Understanding Intracellular Redox Regulation in Methanogens: Characterization of the Components and Targets of the NADPH-dependent Thioredoxin System from Methanosarcina acetivorans

All cells have a reduced intracellular environment. In the presence of oxygen, the non-specific oxidation of intracellular components leads to the production of reactive oxygen species (ROS) within cells leading to oxidative stress. During oxidative stress labile cofactors (e.g. Fe-S clusters) are lost and deleterious disulfide bonds are formed within proteins. Intracellular redox maintenance systems are used to direct reducing equivalents towards the repair of oxidatively-damaged proteins. The thioredoxin system is the ubiquitous intracellular redox system, found in virtually all species. The canonical thioredoxin system is comprised of a NADPH-dependent thioredoxin reductase (TrxR) that functions to reduced thioredoxin (Trx). Although the thioredoxin system is well understood in many bacteria and eukaryotes, it is far less understood in archaea, in particular strictly anaerobic methane-producing archaea (methanogens). Methanogens are the only organisms capable of methane production. Biologically produced methane is essential for the global carbon cycle, but is also a byproduct of agriculture and farming of ruminants thus exacerbating the extent of anthropogenic climate change. The ability of methanogens to produce methane requires a large number of oxygen-sensitive metalloenzymes. However, methanogens can survive oxygen exposure, indicating that they possess intracellular redox maintenance systems. Methanogens use the deazaflavin F420 and the Fe-S cluster protein ferredoxin as primary electron carriers, instead of NADPH. Results presented here reveal that Methanosarcina acetivorans, and likely the majority of methanogens, use NADPH-dependent thioredoxin systems. NADPH is produced through the oxidation of the primary electron carriers F420 and ferredoxin. M. acetivorans contains multiple Trx homologs (MaTrx1-7) that serve alternative purposes within M. acetivorans. In particular, MaTrx3 and MaTrx6 are membraned associated where they likely function in the oxidation/reduction of extracellular proteins. MaTrx7 is the primary intracellular Trx, as it is the only MaTrx reduced by MaTrxR, and it is capable of reducing several hundred M. acetivorans proteins. Enzyme assays reveal that M. acetivorans can produce NADPH in the presence of oxygen, supporting a role for the NADPH system in response to oxidative stress. Overall, these results provide insight into the roles of a thioredoxin system in M. acetivorans, which may lead to methods to control methane production in methanogens

The Relationship between Motivation for and Engagement in Good and Poor Behavior in Youth Ice Hockey

Moral development is often an omnipresent reason for parents supporting adolescent participation in youth sport (Arthur-Banning et al., 2018). However, motivational forces that influence both the cognitive and behavioral manifestations of moral and immoral behavior in youth sport remain convoluted (Hodge & Lonsdale, 2011). Ryan and Deci (2000) proposed motivation is a function of environmental structures that fluctuate on a continuum of overt control or support of autonomy. Theoretically, support of autonomy relates to intrinsic forms of motivation, whereas controlling environments relates to extrinsic forms (Ryan & Deci, 2000). Youth hockey athletes (N= 68, Mage = 12.24, SDage = 2.33) completed measures of self-reported hockey-specific good and poor sport behavior (GPSB; Lavoi & Stellino, 2008), and two adapted versions of the behavioral regulation in sport questionnaire (BRSQ; Lonsdale et al., 2008) to reference good and poor hockey behaviors. Correlations were initially conducted to analyze the data followed by linear regressions to interpret directionality of theorized relationships. Results indicated intrinsic motivation for good sport behavior was a significant predictor of both dimensions of good sport behavior; Concern and Respect for Others and Graciousness (F(1,65) = 4.71 -6.22, p = .02 - .03, B = .26 - .30). Extrinsic motivation for poor sport behavior was a significant predictor of one dimension of poor sport behavior; Play and Talk Tough (F(1,65) = 4.59, p = .04, B = .26) and intrinsic motivation for poor sport behavior was a significant predictor of the other dimension of poor sport behavior; Complain and Whine (F(1,65) = 6.04, p = .02, B = .29). Findings emphasize the necessity to measure domain specific moral and immoral motivations for behaviors to thoroughly understand the complexities associated with moral development in the youth sport context. Implications of the current results, limitations, and future research directions will also be presented

Venous Air Embolism Leading to Cardiac Arrest in an Infant with Cyanotic Congenital Heart Disease

Gas emboli, including venous and arterial, are a rare but important complication of pediatric cardiac surgery. They have the potential to have devastating consequences and require prompt recognition and treatment. We present a case of gas embolism occurring in the immediate postoperative period in an infant with cyanotic congenital heart disease after palliative cardiac surgery resulting in cardiopulmonary arrest. The embolism was diagnosed by visualization of air within the vessel creating an airlock and occluding pulmonary blood flow