Role of Shape in the Self-Assembly of Anisotropic Colloids.

Self-assembly is the process of spontaneous organization of a set of interacting components. We examine how particle shape drives the self-assembly of colloids in three different systems. When particles interact only via their shape, entropic crystallization can occur; we discuss a design strategy using the Voronoi tesslelation to create “Voronoi particles,” (VP) which are hard particles in the shape of Voronoi cells of their target structure. Although VP stabilize their target structure in the limit of infinite pressure, the self-assembly of the same structure at moderate pressure is not guaranteed. We find that more symmetric crystals are often preferred due to entropic contributions of several kBT from configurational degeneracies. We characterize the assembly of VP in terms of their symmetries and the complexities of the target structure and demonstrate how controlling the degeneracies through modifying shape and field-directed assembly can improve the assembly propensity. With the addition of non-adsorbing, polymers, hard colloids experience an attraction dependent on polymer concentration, the form of which is dictated by the colloid shape; we study a system of oblate, spheroidal colloids that self-assemble thread-like clusters. In both simulation and experiment the colloids condense into disordered droplets at low polymer concentrations; at higher concentrations we observe kinetic arrest into primarily linear clusters of aligned colloids. We show that the mechanical stabilty of these low-valence structures results from the anisotropic particle shape. Particle surfaces can be patterned with metal coatings, introducing enthalpic attraction between particles; we study a system of prolate spheroidal colloids, half-coated in gold. We show with experiments and computer simulations that Janus ellipsoids can self-assemble into self-limiting one-dimensional fibers with shape-memory properties, and that the fibrillar assemblies can be actuated on application of an external alternating-current electric field. Actuation of the fibers occurs through a sliding mechanism (allowed by the curved ellipsoidal surface) that permits the reversible elongation of the Janus-ellipsoid chains by ~36%. In each case, we find shape plays a critical role. By understanding and isolating its impact, we enhance shape's utility as a parameter for the design of self-assembling colloids.PhDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111630/1/baschult_1.pd

Administrative Trust as a Contributor to Forensic Coach Burnout and Exit

This study sought to determine whether a relationship exists and its extent between intercollegiate forensic coach trust in university administrators and burnout and exit in intercollegiate forensic coaches. Specifically, this study examined the relationship between intercollegiate forensic coach trust in their university administrators with both intercollegiate forensic coach satisfaction and intercollegiate forensic coach burnout in predicting intercollegiate forensic coach exit from forensics. Fifty-seven intercollegiate forensic educators participated in the research, including 37 directors of forensics. Data analysis revealed significant relationships between intercollegiate forensic coach trust in university administrators, intercollegiate forensic coach satisfaction, intercollegiate forensic coach burnout, and intercollegiate forensic coach exit from forensics. However, regression analyses revealed only trust in administrators and job satisfaction respectively predicted intercollegiate forensic educators’ exit from forensic activity. The research provides discussion pertaining to implications of the findings, limitations of the study, and recommendations for future research

Family and Social Networks Considered in an Examination of Exurban Migration Motivations

Exurbia is growing in population and land use mainly due to internal migration from urban and suburban areas . Existing literature has identified urban decay, housing affordability, and natural amenities as key reasons why Americans move to exurbia . The literature, however, largely overlooks the potential influence of family and social networks . Drawing from previous studies in non-exurban contexts, this paper asks: are family and social networks attracting migrants to exurbia? The authors conducted in-depth, semi-structured interviews with 34 exurbanites in northern Indiana and northwest Illinois, allowing residents to describe their migration decisions without forcing participant responses into predefined survey categories . Twenty-five of the thirty-four interviewees cited family and social network influences . Networks guided moves not only to particular exurban areas, but also to specific exurban properties . We submit these findings in an attempt to further theorize exurban migration and deepen understanding of these move

Eastern Airlines: The Rise and Fall of The Wings of Man

This paper examines the rise and fall of Eastern Airlines from 1928 to 1991. lt outlines the carrier\u27s development under a succession of leaders and discusses the major events of each leader\u27s reign. From a small contract mail carrier known as Pitcairn Aviation, Eastern grew to become one of the largest airlines in the free world. But after 26 years of growth and prosperity under the leadership of Eddie Rickenbacker, the airline began to stumble in the early 1960s. Frank Lorenzo took the reins in 1986 and began selling the carrier\u27s assets while attempting to destroy the unions. After a massive employee strike in 1989 and a bout with bankruptcy, Eastern stopped flying in January 1991

Partially-supervised protein subclass discovery with simultaneous annotation of functional residues

<p>Abstract</p> <p>Background</p> <p>The study of functional subfamilies of protein domain families and the identification of the residues which determine substrate specificity is an important question in the analysis of protein domains. One way to address this question is the use of clustering methods for protein sequence data and approaches to predict functional residues based on such clusterings. The locations of putative functional residues in known protein structures provide insights into how different substrate specificities are reflected on the protein structure level.</p> <p>Results</p> <p>We have developed an extension of the <it>context-specific independence </it>mixture model clustering framework which allows for the integration of experimental data. As these are usually known only for a few proteins, our algorithm implements a partially-supervised learning approach. We discover domain subfamilies and predict functional residues for four protein domain families: phosphatases, pyridoxal dependent decarboxylases, WW and SH3 domains to demonstrate the usefulness of our approach.</p> <p>Conclusion</p> <p>The partially-supervised clustering revealed biologically meaningful subfamilies even for highly heterogeneous domains and the predicted functional residues provide insights into the basis of the different substrate specificities.</p

HMM Logos for visualization of protein families

BACKGROUND: Profile Hidden Markov Models (pHMMs) are a widely used tool for protein family research. Up to now, however, there exists no method to visualize all of their central aspects graphically in an intuitively understandable way. RESULTS: We present a visualization method that incorporates both emission and transition probabilities of the pHMM, thus extending sequence logos introduced by Schneider and Stephens. For each emitting state of the pHMM, we display a stack of letters. The stack height is determined by the deviation of the position's letter emission frequencies from the background frequencies. The stack width visualizes both the probability of reaching the state (the hitting probability) and the expected number of letters the state emits during a pass through the model (the state's expected contribution). A web interface offering online creation of HMM Logos and the corresponding source code can be found at the Logos web server of the Max Planck Institute for Molecular Genetics . CONCLUSIONS: We demonstrate that HMM Logos can be a useful tool for the biologist: We use them to highlight differences between two homologous subfamilies of GTPases, Rab and Ras, and we show that they are able to indicate structural elements of Ras

Pharmaceutical pollution in marine waters and benthic flora of the southern Australian coastline

Environmental context Most human pharmaceutical waste is discharged to the environment. While the presence of pharmaceuticals in freshwater systems is well documented globally, little is known of the impact on marine ecosystems. We measured pharmaceuticals in a marine environment in south-eastern Australia and found pharmaceutical concentrations around 24 000 times higher in benthic flora than in the marine surface waters. We discuss the potential use of seaweeds as biological indicators of pharmaceutical pollution. Rationale Pharmaceuticals are emerging pollutants of concern with a range of adverse consequences for organisms and ecosystems. Their presence in freshwater and estuarine systems has been well documented, but less is known about their prevalence in open ocean, or their uptake by benthic flora. This preliminary survey of the southern Australian coastline sought to measure the concentrations of key pharmaceuticals in both surface waters and benthic flora. Methodology This study used LC-MS/MS to measure the concentration carbamazepine, tramadol and venlafaxine in (1) samples from wastewater treatment plants, (2) ocean surface waters and (3) several species of benthic flora. Surface waters and benthic flora were sampled at two sites near waste water treatment plant (WWTP) discharges, and one site away from any discharge. Results All three pharmaceuticals were detected in surface water samples with their risk assessed (via risk quotient) as medium risk (carbamazepine) or low risk (venlafaxine, tramadol). All three pharmaceuticals were also detected in benthic flora, particularly in brown macroalgae Tramadol was measured at a maximum of 34.7 ng 

Bases expert statement on the use of music for movement among people with Parkinson's

First published in The Sport and Exercise Scientist, February 2020, Issue 63. Published by the British Association of Sport and Exercise Sciences – www.bases.org.uk.Music is an artistic auditory stimulus that unfolds over time. It can prime specific actions and prompt engagement in physical activity as well as heighten motivation during motor tasks (Karageorghis, 2020). Contrastingly, it can be used to downregulate arousal to facilitate the transition from an active to a sedentary state or to ameliorate anxiety. In therapeutic applications, musical features such as rhythm, melody and harmony have been shown to elicit psychological and physiological changes (Thaut & Hoemberg, 2014). Parkinson’s is a degenerative neurological condition in which the loss of dopamine neurons results in impaired initiation and control of movement, with common symptoms including tremor, postural instability and gait disturbance. There are also non-motor effects that include apathy, anxiety and depression. Medication does not alleviate all manifestations of the condition and there is presently no known cure (Obeso et al., 2017). It is notable that people with Parkinson’s are estimated to be 30% less active than agematched peers (Ramaswamy et al., 2018). Nonetheless, evidence is emerging that a range of exercise-based and social activities that involve musical engagement can serve to address the common symptoms and enhance quality of life (Thaut & Hoemberg, 2014). This statement brings together an international interdisciplinary team to outline what is known about music-related applications for people with Parkinson’s, and to provide recommendations for exercise and health practitioners.Peer reviewe