The Influence of Negative Affect on Self-Referent Sentence Processing and Memory Performance

The current study investigated how a negative mood state affects lexical and sentence processing in individuals that have never experienced depression. Specifically, the goal of this research was to investigate how an induced negative mood state affects the judgment of sentence plausibility and memory for lexical information in a self-referent context. This study also aims to further theories related to the processing of emotion that require more evidence to differentiate between the effect of a transient mood state and the experience of prolonged negative affect. Eighty-five Kansas University students performed 2 experimental blocks each containing 48 randomized sentences, including 18 self-referent sentences in each block. All sentences contained a final word that was chosen according to its negative, positive or neutral valence. The dependent variables were reading time for the sentence final word, reaction time for making the semantic plausibility judgment, and the response choice provided based on sentence content. The two experimental blocks of the reading task were separated by a mood induction procedure where participants were asked to consider a sad moment in their life while listening to Prokokiev's "Russia under the Mongolian yoke." Our results indicate that while in the negative mood state participants were much slower to reject the self-statements ending with a negative word. This effect occurred even though participants spent less time reading the sentence final words while in the negative mood. Overall, our response choice analyses indicated that participants were also less likely to judge the negative self-referent statements as implausible and more likely to accept the positive self-statements. Considering memory performance, we found that negative mood decreases overall memory performance. Valence analyses suggest a bias to recall positive self-referent targets regardless of mood state. Our findings support trait-specific models of emotion processing that have shown a positive cognitive processing bias in nondepressed populations

Morphological, physiological and behavioural evaluation of a ‘Mice in Space’ housing system

Environmental conditions likely affect physiology and behaviour of mice used for life sciences research on Earth or in Space. Here, we analysed the effects of cage confinement on the weightbearing musculoskeletal system, behaviour and stress of wild-type mice (C57BL/6JRj, 30 g b.wt., total n = 24) housed for 25 days in a prototypical ground-based and fully automated life support habitat device called “Mice in Space” (MIS). Compared with control housing (individually ventilated cages) the MIS mice revealed no significant changes in soleus muscle size and myofiber distribution (type I vs. II) and quality of bone (3-D microarchitecture and mineralisation of calvaria, spine and femur) determined by confocal and micro-computed tomography. Corticosterone metabolism measured non-invasively (faeces) monitored elevated adrenocortical activity at only start of the MIS cage confinement (day 1). Behavioural tests (i.e., grip strength, rotarod, L/D box, elevated plus-maze, open field, aggressiveness) performed subsequently revealed only minor changes in motor performance (MIS vs. controls). The MIS habitat will not, on its own, produce major effects that could confound interpretation of data induced by microgravity exposure during spaceflight. Our results may be even more helpful in developing multidisciplinary protocols with adequate scenarios addressing molecular to systems levels using mice of various genetic phenotypes in many laboratories

Abstract

I would like to thank my adviser, Dr. Stacey Hust, for the time and effort that she also put into this project. Without her guidance, this project would not have been possible. She has served not only as an adviser, but also a role model and friend, and I truly appreciate all she has done. Additionally, I would like to thank my committee members, Erica Austin and Bruce Pinkleton, for their guidance throughout the project and their encouragement. I would also like to acknowledge the support and help my fiancé Shawn Willoughby provided. Fortunately for me, Shawn is not only incredibly supportive but also talented, and he was able to serve as the graphic designer for the project. Shawn’s help with the alterations of the advertisements is more than appreciated, especially the help he provided voluntarily before the project had funding. Additionally, I would like to thank my parents and my brother for their support throughout the process. I appreciate the words of encouragement and the continued reminders to just “take it one item at a time ” when the to-do list got a little long. I would also like to thank my colleagues and good friends Cassie Norman and Hollie Smith for their continued support, encouragement and friendship. This investigation was supported in part by funds provided for medical an

Quantification of Small Extracellular Vesicles by Size Exclusion Chromatography with Fluorescence Detection

Chemical analysis of small extracellular vesicles (sEVs) circulating in body fluids holds potentials in noninvasive diagnosis of diseases and evaluation of therapeutic treatments. However, quantification of sEVs remains a challenge due to lacking of cost-effective analytical protocols. Herein we report a facile method based on size exclusion chromatography with fluorescence detection (SEC-FD) for sEVs quantification. After removal of cells and cell debris, a 0.50 mL sample (e.g., cell culture medium) is incubated with CM-Dil dye to fluorescently label sEVs. The incubation solution is then separated on a SEC column packed with Sepharose CL-4B. The eluent is monitored fluorescently at Ex553 nm/Em570 nm by using a fluorometer equipped with a 50-μL flow through cuvette. Separation efficiency of the proposed SEC-FD method was evaluated by analyzing 100 nm liposomes and albumin-FITC conjugate. Liposomes were eluted out in less than 6 min, about 10 min before albumin-FITC. A separation repeatability (RSD in retention time) of 1.4% (<i>n</i> = 5) was obtained for liposomes. In analysis of cell culture media, linear calibration curves based on SEC-FD peak height versus sEVs concentration were obtained with <i>r</i>² value of 0.996. Intraday quantification repeatability (RSD in peak height) was 3.2% (<i>n</i> = 5). The detection limit was estimated to be 2.9 × 10⁷ exosome particles/mL. The proposed assay was applied to the first study of sEVs secretion from TK6 cells cultured in serum-free medium for a culturing period from 1 to 48 h

The Effect of Overlearning on Long-Term Retention

Once material has been learned to a criterion of one perfect trial, further study within the same session constitutes overlearning. Although overlearning is a popular learning strategy, its effect on long‐term retention is unclear. In two experiments presented here, 218 college students learned geography facts (Experiment 1) or word definitions (Experiment 2). The degree of learning was manipulated and measured via multiple test‐with‐feedback trials, and participants returned for a final cued recall test between 1 and 9 weeks later. The overlearners recalled far more than the low learners at the 1‐week test, but this difference decreased dramatically thereafter. These data suggest that overlearning (and its concomitant demand for additional study time) is an inefficient strategy for learning material for meaningfully long periods of time