29th Hayes Graduate Research Forum (February, 2015)

Permanent URI for this collection

https://kb.osu.edu/handle/1811/64343

Arts
1st place: Schroeder, Janet
Description | Full Text PDF
2nd place: Levitt, Sarah
Description | Full Text PDF
3rd place: Erken, Emily

Biological Sciences
1st place: Liu, Xiaoyu
Description | Full Text PDF
2nd place: Natarajan, Gayathri
Description | Full Text PDF
3rd place: Olson, Erik
Description | Full Text PDF

Business
1st place: Awate, Kiran
Description | Full Text PDF
2nd place: Singh, Amitkumar
Description | Full Text PDF
3rd place: Lu, Shaohua
Description | Full Text PDF

Education and Human Ecology
1st place: Hooper, Emma
Description | Full Text PDF
2nd place: Henderson, Trevion
Description | Full Text PDF
3rd place: Weinhold, Kellie
Description | Full Text PDF

Engineering
1st place: Deitz, Julia
Description | Full Text PDF
2nd place: Verma, Navni
Description | Full Text PDF
3rd place: Huang, Evan
Description | Full Text PDF

FAES
1st place: Testen, Anna
Description | Full Text PDF
2nd place: Lee, Michelle
Description | Full Text PDF
3rd place: DiCaprio, Erin
Description | Full Text PDF

Humanities
1st place: Potyondy, Patrick
Description | Full Text PDF
2nd place: Garcia, Christina
Description | Full Text PDF
3rd place: Stewart, Spencer
Description | Full Text PDF

Math and Physical Sciences
1st place: Wang, Linan
Description | Full Text PDF
2nd place: Wang, Bo
Description | Full Text PDF
3rd place: Kafka, Kyle
Description | Full Text PDF
3rd place: Walder, Brennan
Description | Full Text PDF

Professional Biological Sciences
1st place: McCracken, Christie
Description (first paper) | Full Text PDF
Description (second paper) | Full Text PDF
2nd place: Wang, Feifei
Description | Full Text PDF
3rd place: Smith, Jade

Social and Behavioral Sciences
1st place: Roberts, Ian
Description | Full Text PDF
2nd place: McKim, Daniel
Description | Full Text PDF
3rd place: Belding, Jennifer
Description | Full Text PDF

Poster Division: Arts, Humanities, and Social Sciences
1st place: Conley, Claire
Description | Full Text PDF
2nd place: Clark, Allison
Description | Full Text PDF
3rd place: Paulose, Hanna
Description | Full Text PDF

Poster Division: Biological Sciences
1st place: Niraula, Anzela
Description | Full Text PDF
2nd place: Westfall, Alexandra
Description | Full Text PDF
3rd place: Chadwick, Jessica

Poster Division: Engineering, Math, and Physical Sciences
1st place: Riegner, David
Description | Full Text PDF
2nd place: Akah, Ebiji
Description | Full Text PDF
3rd place: Elghannai, Ezdeen

Browse

Now showing 1 - 20 of 37

Investigating the Academic and Social Experiences of Black Male Collegians Formerly in Foster Care
(2015-02) Henderson, Trevion; Strayhorn, Terrell
The purpose of this study was to explore the educational backgrounds and experiences of Black male collegians formerly in foster care. Interviews were conducted with 11 Black male foster care alumni who were current students or recent graduates of degree-granting postsecondary institutions. During this qualitative study, Black male collegians formerly in foster care (BMFCCs) were interviewed via one-on-one, semi-structured interviews. Themes surrounding (a) college-going motivations, (b) college-going and transition processes, and (c) collegiate experiences of Black male collegians formerly in foster care emerged after analysis of interview data. Implications for policy, practice, and future research are discussed.
The Development of a Tomato-Soy-Arugula Seed Beverage for Prostate Cancer Clinical Trial
(2015-02) Lee, Michelle C.; Schwartz, Steven J.
The relationship between tomato, soy, and cruciferous vegetables with lower risk of prostate cancer has been investigated in several prospective epidemiological studies. It is hypothesized that the combination of these foods reduces the risk of prostate cancer to a greater extent than any single food alone. Cruciferous vegetables such as arugula are rich in a group of compounds called glucosinolates. Upon chewing or tearing of the plant, the endogenous plant enzyme myrosinase is released and hydrolyzes the glucosinolates to isothiocyanates (ITCs). ITCs are bioactive, and have been shown to be chemoprotective in animal and human studies. However, ITCs are not stable in processed food products, and to deliver high levels of ITCs in a food product, they must be converted from glucosinolates immediately before consumption. The purpose of this study is to develop a tomato-soy-arugula seed beverage with optimized delivery of ITCs. The ITCs erucin and sulforaphane were quantified in the tomato-soy-arugula seed beverage under different temperatures, hydrolysis times, pHs, and food matrixes on a C18 column with an optimized HPLC analytical method. By optimizing the time, temperature, matrixes and pH conditions of the tomato-soy-arugula seed beverage, we were able to recover 57% erucin and (67mmol/kg) and 76% sulforaphane (16.4mmol/kg) compared to the control (water). In conclusion, the tomato-soy-arugula seed beverage delivered sufficient doses of ITCs and can be used in future prostate cancer clinical trials.
Molecular Dynamics Simulations of Al-La and Cu-Zr Glass Formation from Liquid
(2015-02) Riegner, David; Windl, Wolfgang
Metallic glasses, a metal lacking any long-range atomic ordering, represent an opportunity to usher in the next generation of engineering materials. Metallic glasses have a unique property set, filling a niche not accessible by any existing materials class: high strength, low modulus, low density, corrosion resistance and net-shape processing techniques. Current theoretical understanding consists of a handful of empirical rules, and the absence of universal predictive criteria for the formation of metallic glass has been a standing issue since their discovery in 1960. The lack of mechanisms understood to compel certain metallic liquids to form amorphous structures and not others, is the single greatest barrier to wide-spread future application of metallic glasses. Using molecular dynamics simulations, structural properties of two systems were considered and compared: Copper-Zirconium, an excellent glass former, and Aluminum-Lanthanum, a mediocre glass former. We propose that a better glass forming system undergoes a subtle and gradual transition from liquid to glass, with crystallization being the most extreme possible path. Tracking each atom’s nearest-neighbor coordination allows the relative severity of the transition from liquid to glass to be ascertained, and subsequently quantified. Comparing traits of glass formers and non-glass formers from each system revealed consistencies in their behavior and an underlying mechanism paramount to glass formation: drastic coordination changes in the undercooled liquid inhibit glass formation, while liquids which remain relatively unchanged, or gradually shuffle their neighbors prior to extreme undercooling form glass more readily. Additional analysis reveals that many relevant characteristics are obtained by looking at changes in just one coordination number, without controlling for topological effects. Most importantly, these results accurately separate glass formers and non-glass formers in the Al-La system.
Ibrutinib enhances IL-17 response by modulating the function of bone marrow derived dendritic cells
(Taylor & Francis Group, 2015-02) Natarajan, Gayathri; Satoskar, Abhay
Ibrutinib (PCI-32765) is an irreversible dual Btk/Itk inhibitor shown to be effective in treating several B cell malignancies. However, limited studies have been conducted to study the effect of this drug on myeloid cell function. Hence, we studied the effect of ibrutinib treatment on TLR-4 mediated activation of bone marrow derived dendritic cell culture (DCs). Upon ibrutinib treatment, LPS-treated DCs displayed lower synthesis of TNF-α and nitric oxide and higher induction of IL-6, TGF-β and IL-18. While ibrutinib dampened MHC-II and CD86 expression on DCs, CD80 expression was upregulated. Further, ibrutinib-treated DCs promoted T cell proliferation and enhanced IL-17 production upon co-culture with nylon wool enriched T cells. Taken together, our results indicate that ibrutinib modulates TLR-4 mediated DC activation to promote an IL-17 response. We describe a novel mode of action for ibrutinib on DCs which should be explored to treat other forms of cancer besides B cell malignancies.
A Worksite Translation of the Diabetes Prevention Program among Employees with Prediabetes
(2015-02) Weinhold, Kellie; Smith, Carla K.
INTRODUCTION: Type 2 diabetes mellitus (T2DM) is a serious medical condition affecting over 12% of Americans and is associated with $58 billion in work-related annual costs. Prediabetes increases risk for T2DM, and is estimated to affect over one third of U.S. adults. There is an evident need to prevent the development of T2DM in at-risk individuals. Adults spend a significant portion of their time at the workplace, suggesting its utility for efforts at health promotion and disease prevention. The Diabetes Prevention Program (DPP) is a lifestyle intervention program that has demonstrated efficacy in preventing or delaying T2DM in at-risk adults, however there is a lack of well-designed research studies evaluating the efficacy of the DPP in the workplace. The primary aim of this study was to implement and evaluate the efficacy of the group-based DPP intervention at The Ohio State University (OSU). METHODS: Seventy-eight employees with prediabetes recruited from OSU were randomized to the 16-week group-based DPP intervention group or a usual care control group. Sixty-eight participants completed data collection at baseline and post-intervention. Clinical and anthropometric measures included body weight, waist circumference, fasting blood glucose and lipids, and blood pressure. Statistical analyses included Pearson chi-square tests for baseline demographic characteristics and Student t-tests within an ANOVA for between and within-group analyses. For data not meeting normality assumptions, Wilcoxon signed rank tests were used for within-group and Wilcoxon rank sum 2-sample test for between-group comparisons. Multivariate analyses between variables were completed using Spearman nonparametric correlations. RESULTS: There were no significant differences in primary outcomes between treatment groups at baseline except for occupation. Mean (±SE) change in body weight for experimental versus control groups was -5.25 kg (±0.55) vs. -0.37 kg (±0.56), (p<0.0001). Fasting glucose was reduced by a mean (±SE) of -8.56 mg/dL (±1.52) and -4.48 mg/dL (±1.79), (p=0.0293), for the experimental versus control groups, respectively. CONCLUSIONS: The worksite was an effective setting to implement the DPP intervention, and facilitated significant reductions in body weight and blood glucose. Evaluation of cost-effectiveness of the intervention for employers and long-term maintenance of weight loss and prevention of T2DM are warranted.
Capitalism is Here to Stay: An Appraisal of the Complicated Relationship Between Art, Art-Making, and the Marketplace
(2015-02) Levitt, Sarah; Feck, Candace
This paper examines the relationship between art and capitalism in America from the 1960s to the present, and questions whether art practices, specifically dance, can offer a form of resistance to dominant economic systems. During the 1960s, postmodern artists’ emphasis on decoupling process and product in an attempt to severe the relationship between art and consumerism led to the development of an anti-labor, pro-institution, pro-business culture in the arts which persists today. As artists experiment with form, content, and style on the fringes of culture with little to no economic benefit, their ideas are appropriated by mainstream interests, like institutions and the media, and enter the marketplace. There, they produce profit the artist never sees, despite having originated the idea or way of thinking. Through an overview of the history of modern and postmodern dance in America in the 20th century, research into the careers of prominent choreographers, an examination of the role of institutions in cultivating the avant-garde, a comparison of practices of art-making and practices of producing goods, and current concerns at the intersection of art and labor, this research looks for outposts of artistic opposition to contemporary capitalism.
Monte Carlo Simulation of Sunlight Transport through Solar Trees – a New Paradigm for Improving Sunlight Capture Efficiency
(2015-02) Verma, Navni; Mazumder, Sandip
Solar photovoltaic (PV) cells arranged in complex 3D leaf-like configurations—referred to as a solar tree—can potentially collect more sunlight than traditionally used flat configurations. It is hypothesized that this could be because of two reasons. First, the 3D space can be utilized to increase the overall surface area over which the sunlight may be captured. Second, as opposed to traditional flat panel configurations where the capture efficiency decreases dramatically for shallow angles of incidence, the capture efficiency of a solar tree is hampered little by shallow angles of incidence due to the 3D orientation of the solar leaves. In this paper, high fidelity Monte Carlo simulation of radiation transport is conducted to gain insight into whether the above hypotheses are true. The Monte Carlo simulations provide local radiation flux distributions in addition to global radiation flux summaries. The studies show that except for near-normal solar incidence angles, solar trees capture sunlight more effectively than flat panels—often by more than a factor of 5. The Monte Carlo results were also interpolated to construct a daily sunlight capture profile both for mid-winter and mid-summer for a typical North American city. During winter, the solar tree improved sunlight capture by 322%, while in summer the improvement manifested was 57%.
Repeated Social Defeat Stress Induces Neuroinflammation and Impairs Hippocampal Neurogenesis That Differentially Regulate Mood and Cognition
(2015-02) Niraula, Anzela; Godbout, Jonathan; Sheridan, John
Repeated social defeat (RSD) is a murine stressor that models several key physiological, immunological, and behavioral alterations observed in humans exposed to psychosocial stress. RSD induces prolonged anxiety-like behavior associated with myeloid cell trafficking into the brain, including the hippocampus. Because the hippocampus (HPC) is a key area involved in neuroplasticity, behavior, and cognition, the goal of this study was to investigate if the stress-induced monocyte trafficking affected hippocampal neurogenesis and cognitive function. Here, we show that RSD increased inflammatory mediators (IL-1β, TNFα and IL-6), enhanced microglia activation and monocyte trafficking (CD45hi) specifically in the caudal hippocampus. RSD also impaired spatial memory recall in the Barnes maze independent of anxiety-like behavior. RSD did not affect the number of proliferating neural progenitor cells and developing neurons when examined 14 hours post-RSD. Nonetheless there was a significant reduction in the number of young neurons and mature neurons in the HPC 10 days and 28 days post-RSD, respectively. Consistent with region-specific neuroinflammation, reduction in the number of mature neurons was greater in the caudal hippocampus of the RSD mice compared to controls. The RSD-induced spatial deficits, which are rostral hippocampus-mediated, were resolved by 28 days. Social avoidance which is caudal hippocampus-mediated still persisted 28 days after stress. Thus, stress-induced neuroinflammation is associated with reduced neuroplasticity, and the stress-induced affective and cognitive deficits are differentially associated with hippocampal neurogenesis.
The Role of Elaboration in Self-Control
(2015-02) Belding, Jennifer; Petty, Richard
People can exert self-control in effortful and non-effortful ways. While some research suggests that low thinking hinders self-control, other research indicates that cognitive resources are not necessary for self-control. Unfortunately, only very few theories articulate the conditions under which careful deliberation is helpful or harmful for effective self-control. To answer this question, we draw on research from the attitudes and persuasion literature and suggest that both the direction and amount of thinking are important for understanding when people will exert self-control. We argue that the experience of a self-control conflict can be conceptualized as an exercise in self-persuasion in that people can thoughtfully persuade themselves to indulge or forgo indulgence. Furthermore, because elaboration increases attitude strength, preferences formed under high elaboration conditions should be more impactful (i.e., resistant to change and predictive of behavior) than those formed under low elaboration conditions. In five studies, participants were randomly assigned to read or generate either goal-inconsistent or goal-consistent thoughts under either high or low elaboration conditions using both dieting and financial self-control conflicts. We hypothesized that elaboration is beneficial for self-control when one has elaborated upon goal-consistent thoughts, but can backfire when one has elaborated upon goal-inconsistent thoughts.
Time-resolved measurement of single pulse femtosecond laser-induced periodic surface structure formation
(2015-02) Kafka, Kyle; Chowdhury, Enam
Time-resolved diffraction microscopy technique has been used to observe the formation of laser-induced periodic surface structures (LIPSS) from the interaction of a single femtosecond laser pulse (pump) with a nano-scale groove mechanically formed on a single-crystal Cu substrate. The interaction dynamics (0-1200 ps) was captured by diffracting a time-delayed, frequency-doubled pulse from nascent LIPSS formation induced by the pump with an infinity-conjugate microscopy setup. The LIPSS ripples are observed to form sequentially outward from the groove edge, with the first one forming after 50 ps. A 1-D analytical model of electron heating and surface plasmon polariton (SPP) excitation induced by the interaction of incoming laser pulse with the groove edge qualitatively explains the time-evloution of LIPSS formation.
Oxidative stress-mediated inhibition of intestinal epithelial cell proliferation by silver nanoparticles
(2015-02) McCracken, Christie; Waldman, W. James
Use of silver nanoparticles (NP) is of interest in the food and food packaging industries for their antimicrobial properties. In order to investigate potential consequences of Ag NP ingestion, this study was performed in the intestinal epithelial cell line C2BBe1. Ag NP were synthesized and characterized prior to biological experiments. The Ag NP had an average diameter of 23 nm as determined by TEM analysis. Treatment of proliferating cells (< 10,000 cells/cm2) with low doses of Ag NP (0.25 µg/cm2 or 1.25 µg/mL) for 24 hours induced 20% necrotic cell death and an 80% reduction in metabolic activity. Ag NP treatment of proliferating cells for 24 hours at 0.25 µg/cm2 induced oxidative stress in cells as indicated by a decrease in the GSH/GSSG ratio. Ag NP treatment with 0.25 µg/cm2 also induced G2/M phase cell cycle arrest and a complete inhibition of Ag NP. An in vitro digestion treatment of Ag NP prior to cell exposure required slightly higher doses (0.5 µg/cm2 or 2.5 µg/mL) to induce the same toxicity, likely due to increased species adsorbed to the surface causing slower Ag dissolution. Treatment of cells with silica, titania, and ZnO NP induced at least partial inhibition of cell proliferation at doses of 10 µg/cm2 (50 µg/mL), but the Ag NP-induced inhibition of cell proliferation at doses 40 times lower reveals a unique mechanism of Ag NP in these cells. Our results in proliferating cells suggest that Ag NP-induced oxidative stress leads to cell cycle arrest and the inhibition of cell proliferation. However, toxicity and induction of oxidative stress was not observed in confluent C2BBe1 cells (>100,000 cells/cm2) treated with up to 10 µg/cm2 (50 µg/mL) Ag NP, suggesting that these cells are not as sensitive to Ag NP. This is likely due to exposure of each cell to a smaller number of Ag NP when the cells are confluent in addition to decreased metabolic activity and increased resistance to toxic agents in confluent cells. Based on these studies, Ag NP ingestion may be able to slow proliferation of stem cells of the intestinal crypt and this is something that needs to be investigated further. The largest effects may be seen in diseased intestines where the epithelium is compromised.
HIV-1 Primer Binding Site:Lysyl-tRNA Synthetase Interaction Affinity Diminishes Upon tRNA Primer Annealing and Extension
(2015-02) Olson, Erik D.; Musier-Forsyth, Karin
The retrovirus, human immunodeficiency virus type 1 (HIV-1), possesses a positive sense RNA genome (gRNA) that is reverse transcribed into proviral DNA upon infection. In order for reverse transcription to occur, HIV-1 co-opts cellular tRNALys3, whose 3 ́ 18 nucleotides are perfectly complimentary to a region with the gRNA, to serve as the primer. tRNALys3 is selectively packaged into virions through its interaction with the cellular enzyme lysyl-tRNA synthetase (LysRS), which in turn interacts with the viral protein responsible for orchestrating virus assembly, Gag. However, the mechanism of tRNALys3 transfer from the packaged LysRS to the primer-binding site (PBS) remains incompletely understood. The PBS is harbored in the 5 ́ untranslated region (5 ́UTR) of the gRNA, a highly conserved segment of the HIV-1 genome. We have recently found that a U-rich stem loop immediately upstream of the PBS mimics the anticodon loop nucleotides of tRNALys3, a critical LysRS recognition element. This tRNA-like element (TLE) specifically binds to LysRS, and can competitively displace tRNALys3 from the synthetase. Furthermore, small angle X-ray scattering analysis revealed that the whole PBS domain (PBS105) mimics the overall 3D shape of tRNA. Overall, these data suggest a mechanism where structural and functional tRNA mimicry by the TLE in the PBS domain facilitate primer release from LysRS and targeting to the 18 nucleotide PBS. An observation from the structural analysis was that both apoPBS and PBS annealed to a DNA oligonucleotide corresponding to the 18 complementary nucleotides in tRNALys3 (antiPBS18) mimicked the overall tRNA shape to a similar degree. In order to further investigate the function of the PBS/TLE domain, we performed a fluorescence anisotropy-based binding study examining LysRS interactions with the PBS domain in various functionally relevant states. We find LysRS has similar affinities for both the apoPBS105 and PBS105:antiPBS18 complex, confirming the SAXS structure indicating both complexes mimic tRNA shape. In order to investigate if the additional tRNA-gRNA contacts outside of the 18 nucleotides of complementarity affected the LysRS interaction, we tested PBS105:primer complexes containing full-length and 3 ́-half tRNAs, finding that PBS:tRNA primer complexes displayed reduced affinities for LysRS under certain conditions. Also, when progressively extended antiPBS18 primers were annealed to PBS105, mimicking the initial steps of reverse transcription, we observed a concomitant drop in LysRS affinity. These data further elucidate the role that LysRS plays in the evolution of the reverse transcription initiation complex.
Social expectations reverse the effects of acetaminophen on economic decision-making
(2015-02) Roberts, Ian; Way, Baldwin
On an average week, 23% of the US population takes acetaminophen (i.e. paracetamol; active ingredient in Tylenol; Kaufman, Kelly, Rosenberg, Anderson, & Mitchell, 2002). Originally viewed as just a physical pain killer, acetaminophen has been shown to affect other psychological processes (DeWall et al., 2010; DeWall, Chester, & White, 2015; Durso, Luttrell, & Way, 2015; Randles, Heine, & Santos, 2013). With such a large proportion of the population routinely taking acetaminophen, it is critical to know how it might affect social and economic outcomes. Here we used a battery of economic games to demonstrate that acetaminophen has consistent effects on decision-making, but the direction of acetaminophen’s effect depends on whether the individual has high or low expectations. In a monetary investment game (i.e. trust game), acetaminophen increased investments from subjects with low expected returns from the trustee, but decreased investments from subjects with high expected returns. Next, in a negotiation game (i.e. ultimatum game), we used sequences of high and low monetary offers to exogenously manipulate the expectations of the responders. Acetaminophen increased the acceptance of relatively unfair offers and reduced the acceptance of relatively fair offers. Finally, acetaminophen also caused trustees in the trust game to be less influenced by their beliefs about how much the investors expected them to return. Thus, acetaminophen also reduced how beliefs about another’s expectations drove reciprocity. Overall, our results demonstrate that acetaminophen has socially important but previously unrecognized dampening effects on how people respond to both financial incentives and disincentives for themselves and for others. Furthermore, our findings highlight what we believe to be a general principle of drug action: that psychological factors can change the behavioral and perhaps clinical effects of drugs.
Minimal intestinal epithelial cell toxicity in response to short- and long-term food-relevant inorganic nanoparticle exposure
(Chemical Research in Toxicology (ACS Publications), 2015-02) McCracken, Christie; Waldman, W. James
Toxicity of commercial nanoparticles of titania, silica and zinc oxides is being investigated in this in vitro study. Particles of these compositions are found in many food items and thus this study is directed towards particle behavior in simulated digestion media and their interaction with intestinal epithelial cell line C2BBe1, a clone of Caco-2 cells, originally isolated from a human colon cancer. Even though the primary particle size of all three particles was below 50 nm, the particles appeared as aggregates in culture media with a negatively charged surface. In the presence of pepsin (~pH 2), the charge on the titania became positive, and silica was almost neutral and aggregated extensively, whereas ZnO dissolved. For silica and titania, treatment with simulated intestinal digestive solution led to a strongly negatively charged surface and particle sizes approaching values similar to those in media. Based on infrared spectroscopy, we concluded that the surface of silica and titania was covered with bile salts/proteins after this treatment. Transmission electron microscopy (TEM) indicated that the C2BBe1 cells internalized all three particles. Toxicity assays included investigation of necrosis, apoptosis, membrane damage and mitochondrial activity. Titania and silica particles suspended in media at loading levels of 10 µg/cm2 exhibited no toxicity. With ZnO at the same loading level, mild toxicity was observed based only on the LDH assay and decrease of mitochondrial activity and not necrosis or apoptosis. Titania particles exposed to the simulated digestion media exhibited mild toxicity based on decrease of mitochondrial activity, likely due to transport of toxic bile salts via adsorption on the particle surface.
Family Expressivity: Caregiver Differences and Child Emotional Reactivity
(2015-02) Hooper, Emma; Feng, Xin
This study considered the process by which children emotionally develop within the context of the child’s environment, as families and especially caregivers play an important role in socializing emotional understanding and expression. We investigated how maternal characteristics, including depression and sensitivity, influenced child emotional reactivity over time, while also considering how overall family expressivity, both maternal and paternal, mediated this association. Data were drawn from the NICHD Study of Early Childcare and Youth Development. The current sample included data from grades three, four, five and six; and includes 710 children with mothers and fathers or mother’s partners (MP). Mothers’ depression and sensitivity towards their children were assessed. Additionally, mothers’ and MPs’ level of expressivity within the family and child emotional reactivity were measured across time. Latent growth modeling was used to analyze the relationships between both maternal sensitivity and depression and later child emotional reactivity, including family expressivity as a mediator. The results of this study revealed that child emotional reactivity was related to earlier levels of maternal depression and sensitivity. Furthermore, this relationship was mediated by positive emotional expressivity within the family; however, these relationships differed depending on mother or father/MP influence. Both mothers’ and father/MPs’ positive emotional expressivity at grade three mediated the relationship between maternal sensitivity and child emotional reactivity at grade four. However, only the maternal model showed a mediational relationship with maternal depression. These findings highlight the differences between caregiver perception and influence, and they suggest areas for intervention when working with the whole family or only the mother-child subsystem.
THE EFFECT OF PHOSPHORYLATION OF MOUSE SAMHD1 ON RESTRICTION OF HIV-1 AND MURINE LEUKEMIA VIRUS INFECTIONS
(2015-02) Wang, Feifei; Wu, Li
Background: The dNTPase SAMHD1 functions as an HIV-1 restriction factor in non-dividing cells by limiting intracellular dNTP levels required to complete viral reverse transcription. Phosphorylation of human SAMHD1 (hSAMHD1) at residue threonine (T) 592 by cyclin dependent kinase 1 (CDK1) and CDK2 impairs its restriction of HIV-1 infection. Mouse SAMHD1 (mSAMHD1) shares 72-74% protein sequence identity with hSAMHD1, and also restricts HIV-1 infection in non-dividing cells. However, it is unknown whether phosphorylation of mSAMHD1 regulates its restriction of retroviral infection. Results: We identified and confirmed that T634 is a phosphosite of mSAMHD1 in dividing cells by mass spectrometry and using a phospho-specific antibody. Using specific inhibitors of CDK1 and CDK2 decreased the level of T634 phosphorylated mSAMHD1 in dividing cells. We generated human U937 and mouse NIH3T3 cell lines stably expressing mSAMHD1 wild-type (WT), phospho-ablative (T634A) or phospho-mimetic (T634D) mutants to examine the effect of T634 phosphorylation on mSAMHD1-mediated restriction of HIV-1 or murine leukemia virus (MLV), respectively. In differentiated U937 cells, overexpression of mSAMHD1 WT or the mutants significantly restricted HIV-1 infection and reduced the intracellular dNTP levels. In dividing NIH3T3 cells, mSAMHD1 WT or the mutants modestly reduced MLV infection. Conclusions: CDK1 and CDK2 phosphorylate T634 of mSAMHD1 in dividing cells. Restriction of HIV-1 infection in non-dividing cells and MLV infection in dividing cells by mSAMHD1 is independent of its T634 phosphorylation. Our results suggest different mechanisms of regulating retroviral restriction by hSAMHD1 and mSAMHD1.
Ethnophytopathology and Survey of Tomato Diseases in Morogoro, Tanzania
(2015-02) Testen, Anna; Miller, Sally
Purpose of Study Tomato (Solanum lycopersicum) is an important crop in the Morogoro Region of Tanzania, providing both income and nutrients to smallholder farmers. Tomato production is constrained by many diseases, but the distribution and severity of key diseases was unknown in the Morogoro Region. Better knowledge of regional tomato disease occurrence leads to improved disease management recommendations for farmers, which can ultimately reduce their reliance on chemical pesticides. To enhance knowledge of tomato diseases in the Morogoro Region, we conducted an ethnophytopathology study to ascertain local plant disease knowledge and a physical survey of tomato diseases in the region. Research Methods The disease survey was conducted in five villages in the Morogoro Region during the wet and dry tomato production seasons. In each village, ten fields were surveyed for tomato diseases. Within each field, three 2-square meter plots were surveyed for disease incidence and severity. A soil health assay was conducted to determine the incidence and severity of soilborne diseases in the region. Soil was collected in each of the disease survey fields and transported to a laboratory, where tomato seedlings (variety ‘Moneymaker’) were grown in these soils. Roots were evaluated five weeks after planting. Roots were rated for symptoms of rot and for incidence and severity of root knot nematode. The ethnophytopathology study was conducted on each farm during the disease survey. Farmers were shown cards with pictures of 20 common tomato diseases and asked to provide the names for these diseases in Kiswahili or their local language. Disease names were translated into English and classified by naming system. Farmers also identified which diseases they felt were most important during both production seasons. Findings The most common diseases during both the dry and wet seasons were early blight (Alternaria sp.), bacterial spot (Xanthomonas sp.), Septoria leaf spot (Septoria lycopersici) and viral diseases. Gray mold (Botrytis sp.) was more prevalent during the dry season, tomato yellow leaf curl virus was more prevalent during the wet season. Root knot disease, caused by species of Meloidogyne nematodes, was found in soils from 39 of 40 fields, indicating that this is a commonly occurring, key disease in the region. Farmers provided local disease names that were most often based on the appearance of disease symptoms, such as ‘yellow disease’ for leaf mold. Local disease names also described disease epidemiology, such as the name ‘fulifuli’ which describes the cloudy, drizzly weather conducive to late blight of tomato. Farmers ranked bacterial spot, root knot nematode, tomato yellow leaf curl virus and late blight as most important for both production seasons. Implications This study highlighted the most commonly occurring tomato diseases in the Morogoro Region. These findings were used to create disease identification and management cards for village farmers. These cards contain management suggestions for key diseases and were distributed to farmers in each of the disease survey villages. These materials have to potential to improve tomato disease management and reduce use of chemical pesticides. Data gathered on local names of tomato diseases will help researchers discuss these diseases and their management with farmers.
Attitudinal Ambivalence: How Consumers Manage it?
(2015-02) Singh, Amit S.; Unnava, H.Rao
Ambivalence often has been viewed as an attitude that has both positive and negative components to it. Ambivalence also is viewed as causing discomfort, thus motivating individuals to reduce it. In this research, we investigate the possibility that individuals choose to be ambivalent or not. Initial results tend to show that ambivalence is something that can be controlled by consumers strategically.
Electron Channeling Contrast Imaging: Rapid Characterization of Semiconductors
(MyJoVE Corporation, 2015-02) Deitz, Julia; Grassman, Tyler
In recent years, solar power has begun to approach cost-competitiveness with conventional power sources due to improvements in efficiency, manufacturing, and economies of scale. However, much of this advancement is reaching a saturation point; the sustainability of current and near-term costs is at risk. It is the next generation of PV technologies, with inherently higher conversion efficiencies and lower costs, that will lead the way to grid parity and greater adoption. For these emerging technologies, achievement of their ultimate potential depends greatly upon the ability to fully harness and exploit their advanced properties, which in turn depends on understanding these properties and their limiters. To this end, the detailed characterization and analysis of advanced photovoltaic materials and structures is necessary for the investigation of the fundamental structure-property relationships. Specifically, characterization via electron microscopy within these materials systems provides vital feedback into ongoing and future materials and device design, synthesis, and test efforts. This research utilizes an emerging technique, electron channeling contrast imaging (ECCI) for thin film, photovoltaic defect characterization. Detailed imaging and characterization of these defects is typically performed using transmission electron microscopy as it provides critical insight into their structure, and it allows for selective imaging through achieving various diffraction conditions. Unfortunately, this is a fundamentally low-throughput approach due to the time-intensive sample preparation, which can lead to significant bottlenecks in research and development cycles. Additionally, sample preparation is inherently destructive, thereby potentially leading to adulterated results. ECCI, on the other hand, obtains selective imaging through use of a scanning electron microscope and as such, it requires little to no sample preparation (i.e. can use as-grown samples). This feature of ECCI allows for rapid, high-throughput imaging of extended defects in crystalline materials. In this contribution, ECCI is used for the first time for imaging defects at an interface in thin films – specifically for the characterization of defects within samples of heteroepitaxial GaP grown on Si(100) substrates, in order to develop a better understanding of the dislocation dynamics in this materials system. Epitaxial GaP on Si has been of interest for nearly four decades as a route for integration of III-V materials with Si substrates for high efficiency photovoltaic applications. This makes this GaP/Si system of particular interest for characterization because further progress in the optimization of the epitaxial processes requires a deeper understanding of the dislocation dynamics, for which ECCI is an ideally suited. Here, the use of ECCI for imaging misfit dislocations at buried GaP/Si interfaces, and the use of these capabilities to determine important materials properties, such as critical thickness is discussed. Images will be shown from a range of GaP/Si samples, including studies of GaP films covering a range of thicknesses (from 30 – 250 nm), both as-grown and high-temperature annealed, for the analysis of misfit dislocation extension/glide at the strained interface. Furthermore, other applications of ECCI never before performed will be discussed such as the use of ECCI to do in-situ experiments which cannot be performed with TEM. This work provides unprecedented access to valuable information regarding the formation and evolution of defects, misfit dislocations, at this complex interface, as well as demonstrating the power of the ECCI technique for semiconductor heteroepitaxial research, in general. Ultimately, ECCI proves that it can be an equally valuable, if not superior (in many applications), technique to TEM for detailed microstructural characterization.
Two-dimensional NMR Measurement and Point Dipole Model Prediction of Paramagnetic Shift Tensors in Solids
(American Institute of Physics, 2015-02) Walder, Brennan; Grandinetti, Philip
A new two-dimensional NMR experiment to separate and correlate the first-order quadrupolar and chemical/paramagnetic shift interactions is described. This experiment, which we call the shifting-d echo experiment, allows a more precise determination of tensor principal components values and their relative orientation. It is designed using the recently introduced symmetry pathway concept. A comparison of the shifting-d experiment with earlier proposed methods is presented and experimentally illustrated in the case of 2H (I = 1) paramagnetic shift and quadrupolar tensors of CuCl2 · 2D2O. The benefits of the shifting-d echo experiment over other methods are a factor of two improvement in sensitivity and the suppression of major artifacts. From the 2D lineshape analysis of the shifting-d spectrum the 2H quadrupolar coupling parameters are ⟨Cq⟩ = 118.1 kHz and ⟨ηq⟩ = 0.88, and the 2H paramagnetic shift tensor anisotropy parameters are ⟨ζP ⟩ = −152.5 ppm and ⟨ηP ⟩ = 0.91. The orientation of the quadrupolar coupling principal axis system relative to the paramagnetic shift anisotropy principal axis system is given by (α,β,γ) = (π, π,0). Using a simple ligand hopping model the tensor parameters in the absence of exchange are estimated. On the basis of this analysis the instantaneous principal components and orientation of the quadrupolar coupling is found to be in excellent agreement with previous measurements. A new point dipole model for predicting the paramagnetic shift tensor is proposed yielding significantly better agreement than previously used models. In the new model the dipoles are displaced from nuclei at positions associated with high electron density in the singly occupied molecular orbital predicted from ligand field theory.

Browse

Recent Submissions