Modeling microscopic swimmers at low Reynolds number

We employ three numerical methods to explore the motion of low Reynolds number swimmers, modeling the hydrodynamic interactions by means of the Oseen tensor approximation, lattice Boltzmann simulations and multiparticle collision dynamics. By applying the methods to a three bead linear swimmer, for which exact results are known, we are able to compare and assess the effectiveness of the different approaches. We then propose a new class of low Reynolds number swimmers, generalized three bead swimmers that can change both the length of their arms and the angle between them. Hence we suggest a design for a microstructure capable of moving in three dimensions. We discuss multiple bead, linear microstructures and show that they are highly efficient swimmers. We then turn to consider the swimming motion of elastic filaments. Using multiparticle collision dynamics we show that a driven filament behaves in a qualitatively similar way to the micron-scale swimming device recently demonstrated by Dreyfus et al.Comment: 12 pages, 10 figure

Predictions of molecular chirality and helical twisting powers: A theoretical study

A theoretical study of a number of chiral molecules has been undertaken using a molecular Monte Carlo simulation approach coupled with calculations of molecular chirality based on a chirality order parameter. Results for a variety of TADDOL (alpha,alpha,alpha',alpha'-tetraaryl-1,3-dioxolan-4,5-dimethanol) derivatives show good agreement with experimental findings for the sign, magnitude, and the temperature dependence of the helical twisting power (HTP). For a photochromic chiral dopant with variable HTP we are able to model the reduction in the HTP when photoisomerization occurs. Our studies on a liquid crystalline material with a single chiral center have reproduced a temperature dependent twist inversion in the material. We discuss the temperature and solvent dependence of the helical twisting power and argue that in all the systems studied here, preferential selection of certain molecular conformations at different temperatures and in different solvents are able to explain the observed experimental behavior of the HTP

Analyzing point of care tools through faculty, resident, and stakeholder buy-in: a cautionary tale

Purpose: Costs for Preston Medical Library’s primary point-of-care (POC) clinical tool have increased to half of the acquisitions budget, while user affiliation data have not been provided to facilitate cost sharing. In response, user preferences for POC tools were analyzed to determine a viable, less expensive alternative to the current subscription. Setting/Participants/Resources: Faculty and residents at the University of Tennessee Graduate School of Medicine (GSM), and other clinical staff at the University of Tennessee Medical Center (UTMC), a 685-bed teaching hospital. Methodology: At the direction of school leadership, a working group of library staff, resident physicians, and medical faculty members was appointed, and data were gathered through individual user surveys of clinical support tools. Three POC tool options were considered. Select clinicians evaluated the tools using a series of questions individually chosen as typical to their disciplines. Additionally, feedback was sought from other AAHSL institutions regarding subscriptions to the tool in question and funding schemes. At the same time, the Dean communicated to the medical campus community that cost increases for the product had become prohibitive, requiring consideration of alternatives. Results/Outcomes: Survey responses revealed a strong preference for the incumbent tool, rating PubMed as the second preferred source, but not substitutable. Working group members preferred the current product at POC, judging one of the candidate tools as “adequate” but less user friendly and more time consuming to access. Hospital leadership also received responses from clinical staff. As a result, a cost sharing agreement with the school was forged. Discussion/Conclusion: A deliberative approach to assessing POC clinical tools was used, resulting in continued access to the preferred product. Enhanced data gathering on a go-forward basis will help to ascertain use patterns by academic and hospital users. The library and the other stakeholders will monitor development of alternative POC tools and costs for future decision making

Task Dependence of Visual and Category Representations in Prefrontal and Inferior Temporal Cortices

Visual categorization is an essential perceptual and cognitive process for assigning behavioral significance to incoming stimuli. Categorization depends on sensory processing of stimulus features as well as flexible cognitive processing for classifying stimuli according to the current behavioral context. Neurophysiological studies suggest that the prefrontal cortex (PFC) and the inferior temporal cortex (ITC) are involved in visual shape categorization. However, their precise roles in the perceptual and cognitive aspects of the categorization process are unclear, as the two areas have not been directly compared during changing task contexts. To address this, we examined the impact of task relevance on categorization-related activity in PFC and ITC by recording from both areas as monkeys alternated between a shape categorization and passive viewing tasks. As monkeys viewed the same stimuli in both tasks, the impact of task relevance on encoding in each area could be compared. While both areas showed task-dependent modulations of neuronal activity, the patterns of results differed markedly. PFC, but not ITC, neurons showed a modest increase in firing rates when stimuli were task relevant. PFC also showed significantly stronger category selectivity during the task compared with passive viewing, while task-dependent modulations of category selectivity in ITC were weak and occurred with a long latency. Finally, both areas showed an enhancement of stimulus selectivity during the task compared with passive viewing. Together, this suggests that the ITC and PFC show differing degrees of task-dependent flexibility and are preferentially involved in the perceptual and cognitive aspects of the categorization process, respectively.National Institute of Mental Health (U.S.) (5R01MH065252-12)Alfred P. Sloan FoundationNatural Sciences and Engineering Research Council of Canada (Fellowship)McKnight Foundation (McKnight Scholar award

Collaborating across Organizations for a Remote Area Medical Event: Providing Consumer Health Information and Assessing Health Literacy

Objective: The University of Tennessee’s Preston Medical Library’s (PML) consumer health information service partnered with local librarians and Remote Area Medical (RAM) to increase consumer health information access as well as assess health literacy levels of RAM attendees. Methods: Librarians contacted RAM and obtained permission to both participate in the Knoxville, TN event and conduct anonymous health literacy assessments using the Newest Vital Sign (NVS) tool. Approval was obtained from PML’s institutional IRB. An email gauging participation interest was sent to local librarians at various institutions. A Zoom meeting was then set up to discuss RAM and participant expectations. A librarian with previous experience of partnering with RAM spoke at the meeting about his experiences and answered questions. Librarians volunteered for specific times so that two people were always at the library’s information table. Results: Ten librarians from across four different academic institutions attended the February RAM event and staffed a table with consumer health information handouts, health information request forms, and other informational materials. 137 people visited the table and 13 filled out health information request forms. Mental health was the subject area most frequently requested. Sixteen participants completed the NVS health literacy assessment tool. Results indicate that the majority of participants likely had adequate health literacy. Conclusions: Participating in the RAM event allowed for collaboration with multiple institutions in the local area, further building relationships for future collaborative efforts. Through participating in the Knoxville RAM event and analyzing collected data, researchers sampled health literacy of RAM attendees and planned more focused consumer health information outreach. Two other RAM events in east Tennessee were cancelled due to the COVID-19 pandemic; the library will participate in the annual Knoxville RAM event on a continual basis