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Investigation of Superconducting Properties in YBCO Using Proton Irradiation
Full text linkWe studied the effect of 600 keV proton irradiation on thin-film Cuprate superconductors. A 500 nm thick YBCO-1237 sample was subjected to a series of proton irradiations using Hope College’s particle accelerator, using a cryocooler to test the resistivity of the sample in between irradiations. We found that the superconducting critical temperature (TC) drastically decreased from 90 K towards zero Kelvin, and the normal state resistivity increased accordingly. The rate of TC reduction to resistivity increase will be used to discuss the fundamental property of the superconductor
How Adjusting Surface Electrode Voltages Affects Referred Sensation Quality
Full text linkReferred sensation is when electrical stimulation at one location activates a nerve that innervates a different location. Achieving referred sensation via surface electrical stimulation for the median nerve experimentally has been found to be difficult and time-consuming. Our long-term goal is to design an electrode array to be placed over the elbow crease and develop an algorithm to adjust the electrode voltages used for stimulation until a good referred sensation in the hand is achieved. Our goal for this project was to evaluate the sensation quality of different stimulation values in an electrode array.
Using an anatomically-based finite element model of the arm and median nerve, electrode voltages that resulted in unique nerve activation were found. Simulations were run with an electrode array consisting of three circular electrodes placed along the elbow crease. The model found 418 selective voltage combinations. Single fascicle selectivity was found for fascicle 6, double selectivity was found for fascicles [6,10], and triple selectivity was found for fascicles [6,8,10]. Unique voltage combinations were identified to be tested with human participants.
Two voltage relationships were chosen to test experimentally. A factorial experimental design was used to determine the effect of electrode voltage changes on the overall sensation quality. Two positions for the array were also tested to simulate variability in electrode placement in a clinical setting. For each set of parameters, participants were asked to report the location of the sensation, what it felt like and how strong it was. This information was used to give an overall quality rating to each set of parameters and was used in the statistical analysis.
Of the four participants in the study, only one felt localized sensation in their hand, while the others felt sensation throughout their forearm as well as the hand. When looking at the factorial analysis results, electrode 2 (in the center) was found to have the largest effect on sensation quality, but this effect wasn’t statistically significant. Future work will involve testing more participants and redesigning the electrode array to more reliably obtain localized hand sensation
Explainability in Multivariate Time Series Classification Machine Learning Models
Full text linkExplainability within models is a crucial part of machine learning (ML) models because it promotes trust in the models by providing insights into how their predictions were determined. Our study applies the classification model XCM\u27s explainability component in identifying the critical features leading to classification decisions on data collected while participants performed patient-handling tasks on manikins. Studies show that nurses sustain musculoskeletal injuries early in their career, attributable to some extent to posture adopted during patienthandling tasks. The ML models classify posture adopted during tasks as good , poor , or, in some cases, neutral , where good posture minimizes the risk of musculoskeletal injuries (especially low back pain) in the participants. Features deemed important by XCM (e.g., lumbar rotation, hip flexion) aligned with expectations from a biomechanical standpoint. Training another ML model using only those features improved model accuracy. Further analysis will assist with determining metrics indicative of good posture
Longitudinal Effects of Meaning-Making Expressive Writing on Mental Health
Full text linkResearch suggests that repeated expressive writing is beneficial for one\u27s health and can help individuals psychologically process adversity (Sexton & Pennebaker, 2009). Because research has demonstrated that expressive writing improves one\u27s outlook on life, it is valuable to determine the most effective method of expressive writing for the best outcomes on mental health. One valuable mechanism by which a journal may improve mental health is through enhancing meaning (Edwards & Van Tongeren, 2020). Accordingly, we examined the longitudinal effects of journaling mental health over time. We hypothesized that participants who journal over a series of weeks with the intention of making meaning would report increased levels of positive mental health over time and relative to those in the standard journaling or neutral conditions. Undergraduate Participants (N = 124) were recruited to participate in a journaling study. Participants completed several baseline measures assessing anxiety (GAD-7), depression (PHQ-8), and meaning in life (MLQ). The study used a mixed longitudinal design where participants were randomly assigned to one of three conditions: meaning-making journaling, standard journaling, and a neutral condition. The longitudinal study took eight weeks to complete. Participants completed five assessments in the lab. The first four assessments were one week apart, and a final session was conducted four weeks after the fourth journaling session. During each session, participants journaled and answered the series of questionnaires. All participants are enrolled, and data are currently finishing being collected. Our next steps include coding the journaling responses and analyzing the data. We predict that (a) over time, those in the meaning-making conditioning will report improved mental health and meaning in life, and (b) these improvements would be significantly greater relative to those in the standard journaling or neutral conditions. We will fully complete these analyses ahead of the CURCA conference
Expanding the Use of Palladium-Catalyzed beta-Aryl Elimination Reactions
Full text linkTransition metal-catalyzed cross-coupling reactions involving organic boronic acids are ubiquitous throughout organic synthesis. Despite the popularity of these methods, some boronic acids, such as those with 2-heteroaryl, 2-fluoroaryl, and cyclopropyl substituents, are incompatible, as these species decompose via protodeboronation prior to their incorporation into the desired reaction. To circumvent the protodeboronation process, the organometallic intermediates typically generated via catalyst transmetallation with a boronic acid can instead be generated via β-carbon elimination Efforts will focus on solving the so-called 2-pyridyl problem and broadening the scope of known coupling partners in a Suzuki-like reaction, then systematically expand to include other palladium- and rhodium-catalyzed reactions with an array of coupling partners generated via β-carbon elimination
Does it Pay to Play? A Dyadic Study Exploring Familial Investment in Organized Youth Sport
Full text linkParents play an important role in the youth sport experience for their child (Bonavolontá, 2021). Two ways that parental investment is evident in youth sport is through parental support and parental pressure. Parental support has been linked to child-athlete enjoyment and enthusiasm in the youth sport setting (Gagné, 2003), whereas heightened stress and anxiety for the child-athlete have been associated with parental pressure (Gould, 2008; O\u27Rourke, 2011). Recent literature has explored family investment in youth sport (fiscal) and discovered that greater investment is associated with greater perceived parental pressure on the athlete, while also showing a decline in the athlete\u27s commitment and enjoyment to their sport (Dunn, 2016). Our study aims to explore fiscal and time investment, while additionally integrating a measure for emotional investment, and incorporating the updated Sport Commitment-2 Questionnaire (Scanlan, 2016). The purpose of this study was to examine how families invest (fiscally, in terms of time, and emotionally) in organized youth sport participation. We hypothesized that the greater amounts of parental investment are present, the less the child-athlete will be committed to sport and enjoy sport, and the more likely the child will experience burnout. In the parent survey, parents responded to demographic information and investment-related questions, such as the time spent at practices and tournaments, yearly family fiscal earnings and the amount of money spent yearly on youth sport, and the Parental Involvement in Sports Questionnaire (PISQ) to explore emotional investment. Athletes (12-19 years old) provided demographic information and completed three established measures: Sport Commitment-2 Questionnaire, Parental Involvement in Activities Scale, and Athlete Burnout Questionnaire. The study is currently in the middle of the data collection phase and the findings are eagerly anticipated
Mechanochemical Formation of Polyacrylamide Nanocomposites: Impact of Nanoparticle Surface Chemistry and Substrate Functionalization
Full text linkOsteoarthritis is a degenerative joint condition, with treatments currently limited to symptom management and invasive surgical procedures. This project investigates the fundamental mechanisms for a potential treatment route that would allow soft material nanocomposites to form within the joint through mechanochemical reactions. To gain fundamental insight into the different chemical pathways for this to occur, this work compares a top-down vs bottom-up approach. The top-down method focuses on the influence of applied oscillatory mechanical stresses on bulk hydrogel polymerization. Polyacrylamide (PAM) is used as a well-studied control system. PAM-nanocomposites were achieved through co-polymerization, with gold nanoparticles with different capping ligands directly added to the PAM precursor solution. A rheometer was used to simultaneously apply the small angle oscillatory shear and monitor gelation time. Initial results indicate decreased gelation time for PAM-nanocomposites with gold nanoparticle capping ligands of citrate and CTAB (cetyltrimethylammonium), relative to no nanoparticles present. Accelerated gelation times, relative to no nanoparticles present, were observed for PVP (polyvinylpyrrolidone) and PAA (polyacrylic acid) capping ligands. Comparing molecular structure vs chemical functionalities, these results suggest structure (e.g. polymer-based capping ligands, PVP and PAA) over functionality (e.g. hydrogen bonding for PAA and citric acid, but not CTAB and to a lesser degree PVP) influences gelation time. The complementary bottom-up method uses a 3-metharcyloxypropyltrimethoxysilane functionalized silica surface and AFM as a nanoscale single point sliding contact to grow a surface bound PAM hydrogel film. Future work will continue to quantify these pathways, examining reactions within a stress-assisted Arrhenius model
Development of a Consistent Proton Induced Gamma Emission Liquid 19F Standard
Full text linkWe developed a new technique to quantify PFAS (Fluorine) contamination in water using Hope College’s particle accelerator. To do this, we created an ~2000 PPM NaF in water standard and carefully controlled the experimental configuration. We are hoping that careful control of the experimental conditions will yield a consistent 19F gamma-ray count per Coulombs from Proton Induced Gamma-ray Emission (PIGE). 3.4MeV protons have enough energy to exit the particle accelerator, travel 27 mm in air, and penetrate into the liquid standard. As protons lose energy in the liquid, nuclear reactions such as (p, p’gamma) with the 19F and 23Na nuclei create gamma rays. The amount of beam incident on the sample was measured with Rutherford backscattering (fit with SimNRA - simulation nuclear reaction analysis software)
Exploring the Effectiveness of Directing Groups for Rhodium-catalyzed Decarbonylation
Full text linkReactions involving carbon-carbon bond activation are of interest to develop methods of functionalizing molecules. Work in the Johnson Group utilizes rhodium-catalyzed decarbonylation to form new carbon-carbon bonds in pyridyl ketones, where the nitrogen on the pyridine ring acts as a directing group. Though this reaction is easily replicated and gives high yields, the need for a pyridine directing group limits the range of molecules that can be synthesized. To broaden the scope of this reaction, novel directing group compounds were synthesized through different routes and their efficacy in the decarbonylation reaction was explored
How Do Just Beliefs Develop? A Systematic Review of the Research
Full text linkPsychological research on the perception of justice has developed the concept of belief in a just world (BJW; Dalbert, 2009). This model includes the General BJW (G-BJW)—people\u27s justice perception of the world in general and Personal BJW (P BJW)—a perception of how fair their personal life is (Likpus et al., 1996; Dalbert, 1999). Adolescence is a crucial time for legal socialization and justice beliefs, yet there is little consensus about the development of these beliefs. The current study aims to conduct a systematic literature review on adolescents\u27 BJW to clarify the existing data on their normative developmental trajectories in youth. This systematic literature review follows the PRISMA model (Moher et al., 2009). The inclusion criteria for this review are having cross-sectional or longitudinal data on G-BJW and P-BJW and must include data under the age of 18. Articles also need to report either a correlation with age or a mean and standard deviation for different age groups. The researchers searched PsycInfo and PsycArticles using the terms belief in a just world AND adolescence, adolescen*, or youth. After scanning 333 titles and abstracts, we reviewed 197 full-text articles. 41 articles met the full inclusion criteria. We also reviewed relevant articles cited in the 41 included studies. A PRISMA flow chart summarizes the search process (see Figure 1). The main results will synthesize effect sizes to understand whether there is scientific consensus around a developmental trajectory of BJW and its strength. If a developmental trajectory does not emerge from existing evidence, this review will help unfold the contextual variables that may differentiate the direction and degree of development. Currently, the literature on BJW frames it sometimes as a positive coping mechanism that promotes feelings of control, an innate human need, or a dangerous belief promoting victim-blaming. Understanding the development of BJW will shed light on the purpose and origin of BJW