Office of Undergraduate Research

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Emphasizing equitable and inclusive access to research opportunities, the University of Maryland's Office of Undergraduate Research (OUR) empowers undergraduates and faculty to engage and succeed in inquiry, creative activity, and scholarship. This collection includes materials shared by undergraduate researchers during OUR events. It also encompasses materials from Undergraduate Research Day 2020, Undergraduate Research Day 2021, and Undergraduate Research Day 2022, which were organized by the Maryland Center for Undergraduate Research.

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COMPARISON OF RIBOSWITCH REPORTER SYSTEMS FOR LIVE CELL IMAGING OF CYCLIC-DI-GMP DYNAMICS IN BACILLUS SUBTILIS POPULATIONS
(2019) Pierre, Yasmine; Spirito, Catherine
Fluorescent riboswitch reporters can be used in vivo to monitor metabolite dynamics. Previous work used a fluorescent yfp reporter based on a cyclic di-GMP responsive riboswitch from Bacillus licheniformis to monitor cyclic di-GMP levels in individual Bacillus subtilis cells. The previous study found that cell fates in Bacillus subtilis are not uniform in the presence of varying cyclic di-GMP levels. It is important to further develop tools that enable single-cell imaging in Gram-positive bacteria. Fluorogenic aptamers are single-stranded RNA molecules that have been evolved via in vitro selection to bind strongly and specifically to fluorophore molecules and emit a fluorescent signal. These fluorogenic aptamers can be used instead of fluorescent proteins in riboswitch reporter systems to provide a more dynamic read-out of metabolite dynamics in cells. However, relatively little work has been done to evaluate the use of these fluorogenic aptamers as reporter systems in Gram-positive bacteria. The objective of this project is to evaluate the use of four different fluorogenic aptamers (Mango-III, Broccoli, dimeric Broccoli, and SpinachII) instead of yfp in a cyclic di-GMP responsive riboswitch reporter system in Bacillus subtilis. All plasmids containing the riboswitch reporters were constructed and successfully transformed into E. coli cells. Subsequently, the cyclic di-GMP responsive riboswitch reporter systems were successfully transformed into B. subtilis WT PY79 and a 𝝙pdeH mutant. Future work involves evaluating their performance in vivo in B. subtilis via laser confocal and fluorescence microscopy.
Dual effect of structure and hydration on magnesium-ion insertion into electrodeposited V2O5 thin films
(2019-10) Johnston, Brandon; Henry, Hakeem; Sahadeo, Emily; Liau, Darrin; Lee, Sang Bok; Lee, Sang Bok
As global energy needs continue to increase, there is a growing demand for next-generation storage technologies that confer high energy density. Lithium-ion battery technologies, the current state of the art, possess a number of limitations that prevent further performance enhancement and safe use. Owing to magnesium's abundance, safety, and high volumetric capacity; magnesium-ion batteries are promising alternatives to lithium-ion storage devices. However, a number of challenges have impeded progress in magnesium-ion battery research, such as magnesium anode passivation and poor magnesium-ion insertion kinetics into traditional metal oxide cathode materials. This research addresses the latter of the two problems by further investigating a well-known potential cathode material for magnesium-ion batteries. Vanadium (V) Oxide, a transition metal oxide with flexible interlayer spacing, has been shown to reversibly intercalate Mg2+ ions with high capacity in its crystalline form. However, new research suggests that amorphous V2O5 cathodes might offer greater capacity for Mg-ion insertion owing to increased void space for monovalent and multivalent ion insertion. In this work, we use two primary electroanalytical techniques--cyclic voltammetry and galvanostatic voltammetry--to systematically investigate the impact of structure, crystallinity, and hydration on the electrochemical performance of electrodeposited V2O5 thin films. Ultimately, our findings suggest that it is structural hydration, rather than film crystallinity, that primarily determines Mg-ion insertion capacity of V2O5 thin films.
Improving Non-Contact Tonometry through Advanced Applanation Techniques and Measurement of Corneal Deformation
(2020) Muessig, James; Ackman, Moshe; Cho, Lauren; Do, Kun; Green, Aaron; Klueter, Sam; Krakovsky, Eliana; Locraft, Ross; Wu, Hongyi; Lin, Jonathan; Scarcelli, Giuliano
Glaucoma, a disease characterized by increased intraocular pressure (IOP) in the eyes, is the leading cause of preventable blindness worldwide. Accurate measurement of IOP is essential to early diagnosis of glaucoma in order to begin treatment and prevent long-term vision loss. Currently, non-contact tonometry, known as an “air-puff test”, is the most common diagnostic method despite its inaccessibility, discomfort, high cost, and reliance on an expert to operate. In order to improve upon this method, we designed an accurate and less invasive measurement system utilizing a novel depth-mapping neural network and a microcontroller-driven valve system. We applanated eyes with a variable-intensity air puff while imaging the deformation with a single camera. Our neural network then processed the image data and generated a three-dimensional deformation map. We compared our results to accepted tonometry measurements in order to validate the accuracy of our system as an alternative diagnostic device. With a lower pressure puff and simplified imaging setup, we were able to accurately measure IOP, improving existing diagnostic techniques in optometry.
Prelinguistic Understanding of Collective & Distributive Events
(2020) Deshpande, Stuti; Lidz, Jeffrey; Knowlton, Tyler
English Universal Quantifiers, like 'each' and 'all', describe events where all actors engage in an action. However, they differ in usage. 'Each' can only describe distributive (individual) actions, whereas 'all' can also describe collective actions. This research seeks to determine if infants can distinguish between collective and distributive events before acquiring language. We showed infants non-linguistic videos of animated chevrons chasing balls either collectively or distributively. We looked to see if infants noticed a difference between the videos. Current results suggest that infants can distinguish between these events, but further work is needed.
Do preschoolers track and evaluate social includers and excluders?
(2020) Knoll, Sarah; Woodward, Amanda Mae; Beier, Jonathan
Exclusion leads to negative effects across the social and cognitive domains (Wesselman & Williams, 2013). Because the consequences of social exclusion can be severe, social psychologists have characterized social-cognitive mechanisms for detecting exclusion and motivating responses to mitigate its effects. Although both adults and children respond to exclusion in ways that facilitate social connection, it is unclear whether two components of a system for detecting and responding to social exclusion, tracking and evaluating a prior excluder, are present in early childhood. The current research investigates whether 4- to 6-year-old children track and evaluate social excluders. Children in both experiments played in inclusive and exclusive ball-toss games. Children then reported explicit social evaluations comparing players from each game by answering who was meaner, a better sharer, or a better play partner for a third party. In Experiment 1, four-year-olds (N=32) had mixed evaluations of the players. An exploratory analysis revealed that children who indicated that the includer was a better sharer (n= 19 of 32) viewed the excluder as meaner (18 of 19, p < .001). In Experiment 2, 96 children, ages 4 to 6 years old, participated in a similar procedure to Experiment 1—now including an explicit memory check question. Children who passed the memory check (n = 68) evaluated includers more positively (44 of 68, p = .02) excluders more negatively (46 of 68, p = .004) and recommended that a new puppet play with the includer (49 of 68, p = .003). These effects were primarily driven by younger children, as 6-year-olds did not evaluate excluders negatively. Future work should determine if children younger than 4 years old can track and detect social exclusion.
Novel Bacterial Sialidase Mutants for Site Specific Sialylation of Biologically Important Glycoproteins
(2020) Liang, Tianyuzhou; Li, Chao; Dai, Yuanwei; Wang, Lai-Xi
Sialylation is a unique modification of glycans existing in different glycoproteins on cell surfaces, which significantly modulates many important physiological and pathological processes, such as anti-inflammatory and tumor metastasis. Despite tremendous efforts on the synthesis of this crucial glycan decoration using chemical and enzymatic methods, site-specific attachment of sialic acid moieties onto biologically important glycopeptides or glycoproteins is still challenging. In the last two decades, converting glycosidases into their transfer mutants has become a fascinating approach in the synthesis of glycoconjugates. In this work, a bacterial α2,6-sialidase (MvNA) from Micromonospora viridifaciens was selected as candidate for efficient transfer of sialic acid in a regio- and stereo-controlled manner due to its inherent trans-sialylation activity. First, wild-type MvNA was cloned and overexpressed in E. coli. Two types of sialidase mutants with mutation site at the nucleophile (Y370) and the general acid/base (D92) residues were then created by site-directed mutagenesis and successfully expressed. In the preliminary activity tests, the wild-type MvNA showed strong hydrolytic activity towards a natural sialylated complex-type N-glycopeptide, while terminal sialic acids from the same glycopeptide can’t be removed by created MvNA mutants, including Y370A, Y370G and D92A. The potential trans-sialylation activities of those sialidase mutants will be systematically tested using various synthetic activated substrate donors, such as sialyl fluorides and nitrophenyl sialosides. We are also aiming to create sialidase mutants derived from other types of sialidases with distinct specificities, e.g. α2,3 and α2,8-linkages. The potential sialidase transfer mutants could provide a new avenue to access the structurally well-defined sialylated glycopeptides and glycoproteins for sialylation bio-function study and therapeutic applications.
Confronting Racism: When, Why, and How?
(2020) Adolph, Kobe; Wessel, Jennifer; Lee, Jaeun
In the face of a transition from Jim Crow era to modern era discrimination, this pilot study was conducted to better understand when, why, and how individuals confront racism. We defined blatant racism as overt and subtle racism as more ambiguous (Pettigrew & Meertens, 1995). Subtle racism is more difficult to detect for both targets and witnesses. Consequently, individuals who witness or experience subtle racism are less likely to confront the perpetrator (Ashburn-Nardo et al., 2008). The ambiguity of these situations leaves the targets questioning their own individual characteristics and those of the perpetrator rather than confronting the perpetrator. Many people are hesitant to accuse someone of being racist because it is unclear how that person will react (Ashburn-Nardo et al., 2008). Fairness theory (Folger & Cropanzano, 2001), and the influence of intent on judgements of fairness posed by Swim et al. (2003), were conceptualized as the basis for our hypotheses. We hypothesized that blatant racism will lead to greater probability of confrontation/wanting to confront and greater racist perceptions than subtle racism. Secondly, we hypothesized that witnesses that are the same race as targets will be less likely to confront/want to confront the perpetrator, but more likely to perceive the perpetrator as a racist. Our findings supported the first hypothesis but did not support the second. Although not the focus of our research, the behavior of our President is relevant because the lack of confrontation of his supporters’ blatantly racist behavior is reminiscent of the racism from the Jim Crow era. Implications and suggestions for future research are discussed.
Synthesis of Novel Cyclized C3-Azoles of Galeterone for Prostate Cancer Therapy
(2020) Mattikalli, Shivani; Thomas, Elizabeth; Njar, Vincent; Purushottamachar, Puranik
In the steroidogenesis pathway, cholesterol undergoes two major modifications at the C17 and C3 positions for the biosynthesis of adrenal (male sex hormones) and gonadal (mineralocorticoids) hormones. The C17–hydroxylation /17,20-lyastion and C3-hydroxy oxidation are catalyzed by CYP17A1 and 3β−HSD enzymes respectively. The formation of C3-oxo metabolite by 3β−HSD is essential for the further metabolism at C5 double bond by 5α-SRD enzyme to produce dihydrotestosterone (DHT), a most potent androgen. These androgenic metabolites are important for the development and maintenance of male sex characters. The abnormal production of androgens and their aberrant interaction with androgen receptor is known for the development and progression of prostate cancer disease. Clinical anti-PC agents abiraterone and galaterone are 3-OH-Δ5-C17-heterocycles substituted steroids. Both agents exert their potent anti-PC activity by reducing androgen biosynthesis through CYP17A1 enzyme inhibition. Due to their structural similarities to endogenous steroids they also undergo metabolism at C3 position by 3β−HSD. Consequently, these two agents have short half-life on oral administration (t1/2~1h). Moreover, both agents suffer from low oral bioavailability (abi-37% and gal-19%), and thus require very high dose to show clinical efficacy. To prevent metabolism by 3- HSD and further by 5-SRD enzymes, the metabolic soft-spot (C3–OH) was appended with imidazole ring to obtain metabolically stable agents with no compromise in anti-prostate cancer properties. This modification (VNPP433-3β) has significantly improved half-life (31 h) which is 24.75-fold superior to Gal’s half-life. Additionally, VNPP433-3β has improved oral absorption of 49.6% bioavailability which is 2.96 superior to Gal’s oral absorption. In the current research we have synthesized various C3-azole compounds such as tetrazoles, triazoles, and diazole using cyclization method on stereospecific azide and amine intermediates. These newly synthesized compounds are under biological activity evaluation. We will be presenting rational behind the design novel C3 azoles, their synthetic detail, and pharmacokinetic data of our lead compound and possibly anti-cancer properties of compounds under study.
The Effects of DMPF on Honey Bee Pathophysiology
(2020) Moon, So Eun; Nearman, Anthony; vanEngelsdorp, Dennis
Varroa destructor is a parasitic mite that is the leading cause of honey bee colony loss in the United States. To mitigate these losses, beekeepers apply acaricide treatments. N-(2,4-dimethylphenyl) formamide (DMPF), the active metabolite in amitraz, was the highest detected pesticide in the 2017 US National Honey Bee Survey (NHBS), where samples of bees and wax were taken from 300 different apiaries across the United States. Although amitraz is relatively non-toxic to bees, very little is known about its effects on honey bee physiology, which has shown to be a useful tool in predicting overall colony health. This study investigates the potential effects of DMPF in adult honey bees across 19 pathophysiological traits. Samples of adult bees were necropsied from colonies with known levels of DMPF in the comb wax and compared to bees from colonies with no DMPF detections. The statistical results indicate potential associations between physiological symptoms in honey bee organs such as the ventriculus, Malpighian tubules, rectum, sting gland, and venom sac to varying DMPF concentrations. These findings serve to identify preliminary evidence for future work quantifying the overall effects of DMPF on colony health.
Analysis of animal use of "4-Poster", a commercial host-targeted tick control device
(2020) Pineda Hernandez, Estefany; Mullinax, Jennifer; Li, Andrew
In the mid-1800s there were 500,000 white-tailed deer. By 1992, the deer population rebounded to an estimated 18 million. The expanded deer population has facilitated black-legged tick expansion throughout the northeast of the United States which has resulted in an increased incidence of Lyme Disease. The main objective of the USDA-ARS Area-wide Tick Control Project is to manage deer and tick populations, as an effort to reduce the number of ticks, thus decreasing Lyme disease transmission potentials. The “4-Poster” is a host targeted tick control device used in USDA's Areawide Tick Control project in Howard County, Maryland. The device has a bait dispenser surrounded by paint rollers coated with permethrin- based “Tickicide” solution. While feeding, deer will brush against the rollers applying permethrin to their ears and neck. The objective of this project is to help evaluate the use of the "4-Poster" device by deer and non-target animals.
The Effects of Discrimination on Black Mothers’ Internalizing Symptoms and Parenting Behavior
(2020) Williams, Amber; Dunbar, Angel
Evidence supports that discrimination has an impact on maternal mental health, and that depression can lead to poor parenting practices, but how might these variables relate for Black mothers? I hypothesize that: Black mothers’ experiences with discrimination will be positively correlated to depressive and anxiety symptoms; depressive symptoms would be positively correlated with punitive and minimizing responses; anxiety symptoms would be positively related to punitive and minimizing responses; and, discrimination will be positively correlated to punitive and minimizing responses to children’s emotions. I conducted a secondary data analysis using data from the School Transitions and Academic Readiness Project (STAR) at the University of North Carolina, Greensboro (N=277). Participants (n=86) included Black mothers and their 4-6 year old children, and measures assessed discrimination, depression, anxiety, and emotional socialization in relation to punitive and minimizing parenting practices. Results revealed a trend association between mothers' reported racial discrimination and their depressive symptoms, r = .18, p < .10, and a significant positive correlation between reported discrimination and anxiety symptoms, r = .22, p < .05. There was a significant positive correlation between mothers’ depressive symptoms and punitive responses, r = .43, p < .05, as well as between mothers’ depressive symptoms and minimizing responses, r = .34, p < .05. There was a significant positive correlation between mothers’ anxiety symptoms and punitive responses, r = .31, p < .05, and a significant positive correlation between anxiety symptoms and minimizing responses, r = .24, p < .05. There was no correlation between discrimination and parenting for either punishing or minimizing responses. These results are necessary to consider when assessing Black families, given that the negative impacts on maternal mental health can lead to decreased academic performance and peer acceptance for children. Future directions should assess the effect of discrimination on parenting responses as mediated by depressive or anxiety symptoms.
Parasympathetic Nervous System Functioning in Adolescents with Anxiety
(2020) Modico, Maggie; Fox, Nathan; Zeytinoglu, Selin
Based on theoretical work on the role of autonomic dysregulation in the development of psychopathology, previous work has shown relations between respiratory sinus arrhythmia (RSA) and anxiety (Chalmers et al., 2016; Blom et al., 2010; Monk et al., 2001). RSA serves as an indicator of adaptability, where high levels of RSA reflect flexible and low levels of RSA demonstrate less flexible responding (Pitting et al., 2013). We hypothesized that participants with an anxiety disorder will have lower RSA at baseline and during social situations than those without anxiety. Participants (N=92) were 15-year-olds selected as part of a larger longitudinal study examining the role of infant temperament on adolescent mental health. 33 participants were diagnosed with an anxiety disorder and 59 participants had no diagnosis. RSA was measured using electrocardiogram (EKG) during baseline, an unstructured social interaction task (Get to Know You, GTKY) and a stressful speech task. We derived RSA from the EKG. Independent t-tests were used. Those with an anxiety disorder (M= 6.44) compared to those with no clinical diagnosis (M= 7.08) demonstrated significantly lower baseline RSA, t =2.97, p=.004. Compared to those with no diagnosis, participants with an anxiety disorder showed lower RSA during GTKY and Speech, t =2.83, p=.006 and t = 2.62, p=.01, respectively. Our results showed that individuals diagnosed with anxiety have lower RSA across both baseline and social tasks than those without anxiety. The role of RSA in anxiety should be examined as it may serve as a biomarker used for treatment and intervention.
Is Facial Mimicry Related to Empathy Levels in Children?
(2020) Talwar, Reshmi; Pan, Alvina; Morales, Santiago; Fox, Nathan
Facial mimicry is thought to be involved in several socioemotional skills, including empathy. In this project, we investigated the presence of facial mimicry and its relationship to empathy in children. We collected electromyographic (EMG) activity using an EEG net as participants observed fearful and happy facial expressions. Additionally, Participants’ caregivers completed the Griffin Empathy Questionnaire (Dadds et al., 2008). First, we confirmed that our EEG facial electrodes captured facial muscle (EMG) activity and differentiated between executed happy and fearful facial expressions (p<.001). As hypothesized, we found greater EMG activity in the Zygomaticus Major cluster for happy, compared to fearful expressions (p<.001). As expected, this pattern was reversed for the Corrugator Supercilii cluster (p<.001). Second, we found evidence for facial mimicry while participants observed various expressions (p=.04). However, facial mimicry was only significant for the Corrugator Supercilii cluster (p=.02) and not the Zygomaticus Major, suggesting that evidence for facial mimicry was exclusive to observing fearful facial expressions. Finally, we found that the extent of facial mimicry was not related to levels of empathy, r(45)=.23, p=.12. Together, our results provide evidence for facial mimicry in childhood. However, we do not provide support for the relation between facial mimicry and empathy. Finally, our findings suggest that EMG activity can be successfully captured using EEG equipment, providing future studies a way to directly examine the relation between facial mimicry and the mirror neuron system.
The Effects of Prediction and Speech Rate on Lexical Processing
(2020) Cole, Alissa; Slevc, Robert
How are we so good at quickly and accurately comprehending speech? Researchers have suggested that we not only process language as we hear it, but also predict what we are likely to hear next (e.g., if you heard "The researcher built a time machine to travel into the.." you might be expecting "future"), which helps our comprehension. What is not yet clear is the necessity of prediction accuracy (e.g., what if you predicted "past" instead of “future”?) or the cognitive processes that underlie this prediction process. The goal of this project was to investigate the effect of lexical prediction on language processing, and how this effect varies with speech rate and individual cognitive abilities. In an active prediction paradigm, participants heard two-sentence passages at fast, medium, or slow rates while predicting the final word of the passage. Instead of hearing a final word, participants were instructed to read a word aloud as quickly as possible, then indicate if this was the word they predicted. The word had about a 50% chance of matching the participant's prediction. Results show that both correct and incorrect prediction facilitated reading time, suggesting that prediction facilitates language processing regardless of prediction accuracy. Additionally, slower speech rate resulted in slower response time across conditions, indicating that language processing may slow to match speech rate. Response times were related to general processing speed, but the effects of prediction accuracy and speech rate were not related to measures of either processing speed or working memory. In all, these results support the hypothesis that active prediction decreases language processing time, which may also be affected by speech rate and general processing speed.
Children's Evaluations of Helpful and Unhelpful Individuals
(2020) Forman, Sydney; Woodward, Amanda; Beier, Jonathan; Beier, Jonathan
Humans are cooperative and often help one another. Although we know that young children are helpful, there is much to understand about children’s evaluations of others who do and do not help. Prior work examined evaluations during middle childhood of helpers and non-helpers in India and the US in different settings (Miller, Bersoff, & Harwood, 1990). American children’s evaluations centered on their relationships with the needy person (e.g. friend or family member) and how severe the person’s need was. These differences in evaluations raise questions of how children’s views of helpful and unhelpful interactions arise, earlier development. The current studies examine 3- to 6-year-old children’s interpretations and evaluations of helpful and unhelpful people. Experiment 1 (N=95 of planned 96) investigated children’s evaluations of people who help versus neutral people and their views of helpful versus unhelpful interactions. Children watched two sets of videos. First, children watched a video of a helper giving tape to someone hanging a poster and a video of a neutral character with another girl. When asked to evaluate the helpful versus neutral characters, children rated the helper more positively (59 of 95, p = 0.01). Then, children watched videos of helpful and not helpful interactions. Overall, children viewed helpful action as more acceptable than unhelpful actions (X^2(1) = 85.01, p < 0.01). Experiment 2 (N=61 of planned 96) expanded this work by examining children’s evaluations of characters who do not help. Preliminary analyses will be presented in the poster.
The Role of Lipid Metabolism in B Cell Immune Functions
(2020) Beher, Richa; Song, Wenxia
Evidence indicates that lipid accumulation due to obesity triggers a low-grade, chronic inflammation, which is correlated with the occurrence of Type 2 diabetes (T2D). Recent studies provide evidence for the essential role that B cells play in obesity-induced inflammation and the development of insulin resistance. In visceral adipose tissue (VAT), B cells generate self-reactive antibodies (autoantibodies), which increase their pathogenicity. They also activate the production of cytokines by T cells through antigen presentation. Lastly, B cells themselves increase the production of inflammatory cytokines while decreasing the production of the anti-inflammatory cytokine IL-10. We hypothesize that neutral lipid accumulation exclusively in B cells will cause them to infiltrate VAT, trigger autoantibody production, and develop an autoimmune pathology. Preliminary research has led to the generation of a B cell-specific CGI-58 knockout (BKO) mice model in order to induce neutral lipid accumulation in B cells. It was found that increased accumulation of triglycerides in CGI-58 BKO mice significantly increased the levels of spontaneous activation in B cells, shown by the increases in the number of germinal center B cells, the surface expression levels of B cell activation markers, and the number of infiltrated lymphocytes in VAT, compared to Flox controls. The goal of this project is to determine the mechanism by which B cell lipid metabolism regulates B cell activation and pathogenicity in obesity-associated insulin resistance.
Encapsulation of Candida albicans in Alginate Polymer
(2020) Okunrinboye, Funke; Karlsson, Amy
Candida albicans is a commensal opportunistic fungal pathogen. It is a polymorphic organism that exists in pseudo-hyphal, hyphal and yeast forms in human hosts. C. albicans causes superficial and systemic infections, including oral thrush, vaginal yeast infections, and systemic bloodstream infections. Systemic candidiasis can be deadly in immunocompromised patients such as transplant recipients and patients that have HIV, cancer, and diabetes mellitus. C. albicans infections are associated with high morbidity and mortality rates yearly. The characteristics of C. albicans associated with an ability to cause infections involve cell adhesion, dimorphism, phenotypic switching, thigmotropism, and biofilm formation. These characteristics aid in yeast dispersal, virulence and resistance to current antifungal therapies. Due to the toxicity of antifungal therapies to human host cells, the resistance of C. albicans to antifungal therapies, and Candida’s ability to escape the white blood cells, newer approaches to better study C. albicans are needed. Encapsulation of yeast cells will allow observation of cell signaling, growth patterns, and, ultimately, enable the development of better alternatives to prevent biofilm formation and C. albicans hyphal growth, thereby limiting virulence. Anionic alginate polymers were used to mimic human host cells for Candida encapsulation observation. and C. albicans strain SC5134 was embedded in the capsules. The cells grew predominantly in the yeast form at 35 °C but showed significant hyphal growth at 37 °C, in both liquid growth medium and in the alginate capsules. The results also show that C albicans can successfully be encapsulated and that growth can be observed in the capsules.
Relations between Memory Measures and Hippocampal Volumes in Early Childhood
(2020) Fine, Carli; Riggins, Tracy
The phenomenon of childhood amnesia, in which only a mere fraction of childhood experiences is remembered, may be due to changes in underlying neural mechanisms supporting memory (Willoughby et al., 2012; Bauer, 2007). However, it is unknown whether lab tasks used to measure childhood memory skills map onto everyday life experiences. This study aims to address that gap through an investigation of two different measures completed by 200 4- to 8-year-old children. One task is a rich open-ended autobiographical interview examining recall for real-world events; the other is a controlled laboratory-based assessment examining memory for temporal order using a series of child-appropriate pictures. This study asks whether both tasks show relations to 1) age group, 2) underlying neural mechanisms, and 3) performance as compared to each other. The hippocampus is a likely candidate underlying behavioral changes during early childhood because it undergoes significant development during this time (Gogtay et al., 2006; Lavenex & Lavenex, 2013) and supports memory in school-aged children and adults (Ghetti & Bunge, 2012). Autobiographical memories were scored using a modified interview coding scheme based on Levine et al. (2002). Temporal order was scored as proportion of adjacent pictures correctly ordered across two 9-item sequences. Hippocampal subregions were delineated using manually identified anatomical landmarks (Riggins et al., 2018). Preliminary results indicate age-related performance differences and hippocampal volume correlations. This work contributes to knowledge about the extent to which naturalistic versus lab-based tasks similarly measure memory abilities.
Understanding Substance Reuse Among Sexual and Gender Minority Individuals With HIV
(2020) Tralka, Hannah; Belus, Jennifer; Satinsky, Emily; C.J., Seitz-Brown; Daughters, Stacey; Magidson, Jessica; Magidson, Jessica
Research shows that people living with HIV (PLWH) who are of sexual and gender minority (SGM) status experience higher rates of substance use disorders (SUDs) compared to heterosexual, cisgender individuals; however, there is a lack of research examining substance use treatment outcomes among individuals with multiple minority statuses. This study explored a multiple minority PLWH population to examine how SGM status influences time to substance reuse, frequency of use, and substance use related problems. Participants included 56 PLWH with problematic substance use who were enrolled in an abstinence-focused inpatient substance use treatment center in Washington, DC. Participants completed 16 sessions and were followed over 12 months post treatment. A discrete time to event logit model was used to examine whether SGM status moderated time to reuse. A total of n=21 individuals self-identified as SGM and n=35 identified as non-SGM. Approximately 64% of the sample returned to substance use at least once over the 12 months. At the end of 12-month follow-up, the survival rate was 20.5% of the overall sample. In the non-SGM group, the survival rate was 37.6% compared with 4.8% in the SGM group. The overall time to event model was significant ( λ2= 25.46, p <.001). The odds of reuse for those with SGM status increased by 1.88 [95% CI: .84, 4.19], suggesting likely need for SGM specialized care and those who identify with multiple minority statuses. Despite strengths of the longitudinal design, future work must replicate these findings in a larger sample.
Weakly-Mixing Systems with Dense Prime Orbits
(2020) Benda, Aaron; Kanigowski, Adam
We provide the first examples of smooth, weak mixing dynamical systems for which all points have dense orbits along primes.