2016 Oral Presentation Abstracts
Scroll down below to view abstracts listed by session and room number. Click on the links below organized by topic area to skip to a specific session.
Morning Sessions by Topic - 9:00 - 10:50 AM
Bioengineering & Mathematical Biology Environmental Engineering & Geography Animal Science Chemistry Biomedical Engineering & Neuroscience |
Afternoon Sessions by Topic - 1:00 - 2:50 PM
Chemical Engineering Psychology Plant Pathology & Agricultural Sciences Nuclear Engineering & Chemistry |
Morning Oral Presentations
Morning Session A, Room 118 - Bioengineering & Mathematical Biology
Description: The Bioengineering & Mathematical Biology session will feature presentations on research at the interface of biology, engineering, and math. These interdisciplinary studies use a variety of technologies and instrumentation to probe a wide range of biological question including the optimization of proteins for future energy conversion applications, implantable glucose sensors for diabetes, an investigation into how lipid droplets form to inform treatments for obesity, and a modeling approach to identify the origins and purpose of concealed ovulation in humans.
Samantha Bedsole
Graduate Student, Chemical & Biomolecular Engineering
Title: Use of sortase mediated ligation for protein attachment to the light-harvesting energy complex, Photosystem I
Abstract: Chimeric proteins exhibit properties derived from each of the original proteins. This can be highly useful in development of a functionalized biomolecule. Historically, this has been accomplished by gene fusions, which suffer from low yields. A post-translational tool which bypasses in vivo synthesis of chimeric proteins is sortase A-mediated ligation. This is an enzymatic fusion of two proteins occurring between an LPXTG and a multi-glycine recognition site on opposing termini. Such applications can be performed in vitro giving more control over environmental influences and more opportunities to study the fusion product. We have used molecular engineering to append a LPXTG recognition sequence on an N-terminus of our multi-subunit protein of interest, the light-energy harvesting complex, photosystem I (PSI). We are working to optimize the fusion of PSI with a C-terminally labeled GGG-green fluorescent protein (GFP) by exploring the affects of enzyme-binding-site-ion concentration and reactant/enzyme ratios on the ligation product yield. The binding yield is assessed using polyacrylamide gel electrophoresis, which allows determination of the apparent molecular weights of the proteins. When a fusion occurs, a peptide bond is formed, yielding a protein product with the additive weight of the individual proteins. The thickness of the molecular weight band for each protein is directly proportional to the concentration of that protein in solution, allowing us to determine the efficiency of the ligation under the reaction conditions. We will use these optimized protein-protein ligation conditions for future work involving energy conversion applications with PSI.
Abstract: Chimeric proteins exhibit properties derived from each of the original proteins. This can be highly useful in development of a functionalized biomolecule. Historically, this has been accomplished by gene fusions, which suffer from low yields. A post-translational tool which bypasses in vivo synthesis of chimeric proteins is sortase A-mediated ligation. This is an enzymatic fusion of two proteins occurring between an LPXTG and a multi-glycine recognition site on opposing termini. Such applications can be performed in vitro giving more control over environmental influences and more opportunities to study the fusion product. We have used molecular engineering to append a LPXTG recognition sequence on an N-terminus of our multi-subunit protein of interest, the light-energy harvesting complex, photosystem I (PSI). We are working to optimize the fusion of PSI with a C-terminally labeled GGG-green fluorescent protein (GFP) by exploring the affects of enzyme-binding-site-ion concentration and reactant/enzyme ratios on the ligation product yield. The binding yield is assessed using polyacrylamide gel electrophoresis, which allows determination of the apparent molecular weights of the proteins. When a fusion occurs, a peptide bond is formed, yielding a protein product with the additive weight of the individual proteins. The thickness of the molecular weight band for each protein is directly proportional to the concentration of that protein in solution, allowing us to determine the efficiency of the ligation under the reaction conditions. We will use these optimized protein-protein ligation conditions for future work involving energy conversion applications with PSI.
Ifana Mahbub
Graduate Student, Electrical Engineering & Computer Science
Title: A Low Power Implantable Glucose Monitoring System
Abstract: According to the survey of the World Health Organization (WHO), about 347 million people worldwide have diabetes. In 2004, about 3.4 million people have died as a result of high fasting blood sugar. Diabetes is one of the leading causes of death in USA and real time monitoring of glucose can certainly prevent these deaths. Implantable micro- and nano-sensors and implantable micro-devices (IMDs) have demonstrated potential for in vivo monitoring of various physiological parameters such as glucose, lactate, CO2, pH, etc [1]. Implantable glucose sensor helps achieve better diabetes management by continuously monitoring the blood glucose (BG) level by providing the patient with specific BG trend line and warning the patient if the glucose level is too high or too low. This paper presents a low power transdermal or implantable glucose monitoring system that has been implemented in the 130 nm CMOS process. The entire system consists of a potentiostat, a signal processing unit (SPU) and a low dropout regulator (LDO). Test results show high linearity of the SPU with a frequency modulated output signal of 100 Hz to 8 KHz over the physiological glucose concentration range (2 mM/Liter to 22 mM/Liter), which produces a sensor current in the range of 100 nA to 10 µA.
Abstract: According to the survey of the World Health Organization (WHO), about 347 million people worldwide have diabetes. In 2004, about 3.4 million people have died as a result of high fasting blood sugar. Diabetes is one of the leading causes of death in USA and real time monitoring of glucose can certainly prevent these deaths. Implantable micro- and nano-sensors and implantable micro-devices (IMDs) have demonstrated potential for in vivo monitoring of various physiological parameters such as glucose, lactate, CO2, pH, etc [1]. Implantable glucose sensor helps achieve better diabetes management by continuously monitoring the blood glucose (BG) level by providing the patient with specific BG trend line and warning the patient if the glucose level is too high or too low. This paper presents a low power transdermal or implantable glucose monitoring system that has been implemented in the 130 nm CMOS process. The entire system consists of a potentiostat, a signal processing unit (SPU) and a low dropout regulator (LDO). Test results show high linearity of the SPU with a frequency modulated output signal of 100 Hz to 8 KHz over the physiological glucose concentration range (2 mM/Liter to 22 mM/Liter), which produces a sensor current in the range of 100 nA to 10 µA.
Zuania Pacheco del Rio
Graduate Student, Chemical & Biomolecular Engineering
Title: Protein stoichiometry in vivo of lipid droplet associated enzymes Ptl1, Ptl2 and Ptl3, eukaryotic homologs of the human lipin enzyme family
Abstract: The increasing population of humans leading a sedentary lifestyle and unhealthy eating habits has made obesity and its associated diseases jump into the top global health concerns, being refer to by the World Health Organization (WHO) as a global epidemic. Obesity is caused by an excessive accumulation of neutral lipids, which are stored in organelles called lipid droplets. Thus a key question in the field is: how do lipid droplets form. The fission yeast Schizosaccharomyces pombe was used to observe the formation and dynamics of lipid droplets. For this research we focus on the lipin family, a group of enzymes which genetic mutations have been related to lipodystrophy (a decrease in the accumulation of lipids) and obesity. A unique time-lapse confocal microscopy technique was used to determine the live cell stoichiometry of lipin proteins when they are expressed with YFP tags. By having a better understanding of the proteins involved in lipid droplet biogenesis we hope to provide a place to focus in future studies for therapeutic treatments in conditions involved with lipid metabolism such as lipodystrophy and obesity.
Abstract: The increasing population of humans leading a sedentary lifestyle and unhealthy eating habits has made obesity and its associated diseases jump into the top global health concerns, being refer to by the World Health Organization (WHO) as a global epidemic. Obesity is caused by an excessive accumulation of neutral lipids, which are stored in organelles called lipid droplets. Thus a key question in the field is: how do lipid droplets form. The fission yeast Schizosaccharomyces pombe was used to observe the formation and dynamics of lipid droplets. For this research we focus on the lipin family, a group of enzymes which genetic mutations have been related to lipodystrophy (a decrease in the accumulation of lipids) and obesity. A unique time-lapse confocal microscopy technique was used to determine the live cell stoichiometry of lipin proteins when they are expressed with YFP tags. By having a better understanding of the proteins involved in lipid droplet biogenesis we hope to provide a place to focus in future studies for therapeutic treatments in conditions involved with lipid metabolism such as lipodystrophy and obesity.
Kelly Rooker
Graduate Student, Mathematics
Title: Modeling the Evolution of Concealed Ovulation
Abstract: Humans are one of the few species in which there are no signs of ovulation visible. Not only can no other male nor female accurately know when another female is in her fertile window, not even the female herself knows. Contrast this with most female mammals who go into heat, have large sexual swellings and/or bright colorations around their genital areas, etc. Evolutionarily, it makes sense that females benefit from advertising their times of fertility in order to attract the highest-quality mates and ensure copulation. Because of these very apparent fitness benefits, such concealment of ovulation has long been an evolutionary mystery, puzzling anthropologists, psychologists, and biologists alike. With no fossil record or concrete evidence to which to turn, little headway has been made thus far in answering it. We here use mathematical modeling to investigate this question. In this talk, I will describe six different hypotheses which have been proposed to explain why concealed ovulation first evolved in our evolutionary past. I will then describe the general mathematical modeling framework we use to identify conditions under which concealed ovulation could have evolved for each of these hypotheses, as well as compare the preliminary results obtained after analyzing each of these models.
Abstract: Humans are one of the few species in which there are no signs of ovulation visible. Not only can no other male nor female accurately know when another female is in her fertile window, not even the female herself knows. Contrast this with most female mammals who go into heat, have large sexual swellings and/or bright colorations around their genital areas, etc. Evolutionarily, it makes sense that females benefit from advertising their times of fertility in order to attract the highest-quality mates and ensure copulation. Because of these very apparent fitness benefits, such concealment of ovulation has long been an evolutionary mystery, puzzling anthropologists, psychologists, and biologists alike. With no fossil record or concrete evidence to which to turn, little headway has been made thus far in answering it. We here use mathematical modeling to investigate this question. In this talk, I will describe six different hypotheses which have been proposed to explain why concealed ovulation first evolved in our evolutionary past. I will then describe the general mathematical modeling framework we use to identify conditions under which concealed ovulation could have evolved for each of these hypotheses, as well as compare the preliminary results obtained after analyzing each of these models.
Morning Session A, Room 235 - Environmental Engineering & Geography
Description: The Environmental Engineering and Geography session will cover a broad range of topics that examine the natural world and anthropogenic influence on it. Steps to address future sustainable goals require a higher level understanding of the natural environment we look to enhance and/or preserve changes to how we operate or build our environment efficiently. This session will explore a wide spectrum of applications to address these goals, that focus on the dynamics of each component. Two discussions will detail important dynamics of select tree systems and what they can tell us about climate change. Another presentation will unveil principles to understanding soil dynamics, and finally, an overview on the fuel consumption savings from coordination of automated vehicles in the built environment will be provided.
Maha Jarrar
Graduate Student, Civil & Environmental Engineering
Title: Granular Strain Measures on Experimental Data
Abstract: Many researchers utilized a broad number of experimental and theoretical approaches to derive constitutive stress-strain relationships for granular materials. According to Bagi (1996), researchers mostly adopt well-known continuum or discrete micro-structural approaches to calculate strains within granular materials. Despite extensive research, neither of the two approaches can fully capture the behavior of granular materials, but rather they are considered as complementary to each other where each has its own strength/limitations in solving granular mechanics problems. Zhang and Regueiro (2015) proposed continuum-based finite strain measures to measure local strains in granular material subjected to large deformations. They used 3D discrete element method data to validate the proposed strains measures. This paper presents an experimental validation of Zhang and Regueiro (2015) approach using 3D images of sheared Ottawa sand specimens. Eulerian finite strains were calculated for representative element volumes within the specimens. The paper will present spatial maps of Eulerian octahedral shear strain and the volumetric strain along with global averaged values.
Abstract: Many researchers utilized a broad number of experimental and theoretical approaches to derive constitutive stress-strain relationships for granular materials. According to Bagi (1996), researchers mostly adopt well-known continuum or discrete micro-structural approaches to calculate strains within granular materials. Despite extensive research, neither of the two approaches can fully capture the behavior of granular materials, but rather they are considered as complementary to each other where each has its own strength/limitations in solving granular mechanics problems. Zhang and Regueiro (2015) proposed continuum-based finite strain measures to measure local strains in granular material subjected to large deformations. They used 3D discrete element method data to validate the proposed strains measures. This paper presents an experimental validation of Zhang and Regueiro (2015) approach using 3D images of sheared Ottawa sand specimens. Eulerian finite strains were calculated for representative element volumes within the specimens. The paper will present spatial maps of Eulerian octahedral shear strain and the volumetric strain along with global averaged values.
Jackeline Rios-Torres
Postdoc, Civil & Environmental Engineering
Title: Contributing to transportation sustainability through utilization of connected and automated vehicle technologies at merging highways
Abstract: Population growth and changes in life style has made unavoidable the massive and extensive use of vehicles. This widespread use generates other issues such as increased traffic accidents, environmental degradation, and traffic congestion. In 2010, 1.24 million road deaths were reported worldwide while in 2014, 6.9 billion hours and 3.1 billion extra gallons of fuel were wasted by urban people due to vehicular congestion, translating to about $160 billion. Merging highways and on-ramps are one of the primary sources of bottlenecks. Recently, Connected and Automated Vehicles (CAVs) are becoming the focus of intensive research, they allow for vehicle-to-vehicle and vehicle-to-infrastructure communication, facilitating the coordination and control of platoons. In this context, the objective of this research work is to develop an online optimization approach for energy efficient and fluent coordination control of CAVs in merging highways. To solve the problem, three steps are followed: (1) The vehicles are ordered following a hierarchical sequence, starting with the vehicle that is closer to the merging zone. (2) The time that each vehicle will take to leave the merging zone is computed as a function of the time the previous vehicle exits the merging zone. This calculation is updated at each instant of time to account for changing traffic conditions. (3) The optimization problem is solved by using the Pontryagin’s minimum principle. Using this principle, we are able to obtain a closed-form analytical solution that can be implemented in real time. According to simulation results, the fuel consumption for a fleet of vehicles can be reduced by almost 50% with the proposed solution when compared to a fleet of vehicles operating in a scenario with not coordination, i.e., the vehicles on the secondary road have to stop until all the vehicles on the main road have crossed the merging zone.
Abstract: Population growth and changes in life style has made unavoidable the massive and extensive use of vehicles. This widespread use generates other issues such as increased traffic accidents, environmental degradation, and traffic congestion. In 2010, 1.24 million road deaths were reported worldwide while in 2014, 6.9 billion hours and 3.1 billion extra gallons of fuel were wasted by urban people due to vehicular congestion, translating to about $160 billion. Merging highways and on-ramps are one of the primary sources of bottlenecks. Recently, Connected and Automated Vehicles (CAVs) are becoming the focus of intensive research, they allow for vehicle-to-vehicle and vehicle-to-infrastructure communication, facilitating the coordination and control of platoons. In this context, the objective of this research work is to develop an online optimization approach for energy efficient and fluent coordination control of CAVs in merging highways. To solve the problem, three steps are followed: (1) The vehicles are ordered following a hierarchical sequence, starting with the vehicle that is closer to the merging zone. (2) The time that each vehicle will take to leave the merging zone is computed as a function of the time the previous vehicle exits the merging zone. This calculation is updated at each instant of time to account for changing traffic conditions. (3) The optimization problem is solved by using the Pontryagin’s minimum principle. Using this principle, we are able to obtain a closed-form analytical solution that can be implemented in real time. According to simulation results, the fuel consumption for a fleet of vehicles can be reduced by almost 50% with the proposed solution when compared to a fleet of vehicles operating in a scenario with not coordination, i.e., the vehicles on the secondary road have to stop until all the vehicles on the main road have crossed the merging zone.
Maegen Rochner
Graduate Student, Geography
Title: Dendrochronological Analysis of Holocene Climate Change in a High-Elevation Whitebark Pine Ecosystem, Wyoming, U.S.A.
Abstract: Climate warming and the resulting upward movement of tree line in some locations has exacerbated other threats to whitebark pine (Pinus albicaulis Engelm.) in the Greater Yellowstone Ecosystem (GYE), such as the mountain pine beetle (Dendroctonus ponderosae Hopkins). The one-two punch of climate warming and resulting increases in infestation, competition, and disease is exerting major stress on the keystone species, and some studies have projected its possible elimination given continued warming in the GYE. Further understanding of whitebark pine forest dynamics is essential for future management practices and conservation. The best way to better understand how these forests will adapt to a warming climate is to study how they have responded in the past. The goal of this study is to use dendrochronological techniques to investigate changing forest dynamics in a high-elevation whitebark pine ecosystem in the Beartooth Mountains of Wyoming during two major Holocene climate fluctuations, the Medieval Climate Anomaly and the Little Ice Age. Results from this study will provide data on the response of high-elevation whitebark pine to anomalously warm and cool temperatures and will provide climate reconstructions that will track in greater detail how the MCA and LIA affected the central Rocky Mountains and GYE. Preliminary results from living and remnant whitebark pines at the site have revealed a chronology that dates back to AD 792. Continued work will reveal the true potential of this prodigious resource on Holocene climate change.
Abstract: Climate warming and the resulting upward movement of tree line in some locations has exacerbated other threats to whitebark pine (Pinus albicaulis Engelm.) in the Greater Yellowstone Ecosystem (GYE), such as the mountain pine beetle (Dendroctonus ponderosae Hopkins). The one-two punch of climate warming and resulting increases in infestation, competition, and disease is exerting major stress on the keystone species, and some studies have projected its possible elimination given continued warming in the GYE. Further understanding of whitebark pine forest dynamics is essential for future management practices and conservation. The best way to better understand how these forests will adapt to a warming climate is to study how they have responded in the past. The goal of this study is to use dendrochronological techniques to investigate changing forest dynamics in a high-elevation whitebark pine ecosystem in the Beartooth Mountains of Wyoming during two major Holocene climate fluctuations, the Medieval Climate Anomaly and the Little Ice Age. Results from this study will provide data on the response of high-elevation whitebark pine to anomalously warm and cool temperatures and will provide climate reconstructions that will track in greater detail how the MCA and LIA affected the central Rocky Mountains and GYE. Preliminary results from living and remnant whitebark pines at the site have revealed a chronology that dates back to AD 792. Continued work will reveal the true potential of this prodigious resource on Holocene climate change.
Brooke Pearson
Undergraduate Student, Geography
Title: External Forcing Factors that Affect Torque Resistance Among Hardwood and Softwood Species, Norris Dam State Park, Tennessee, U.S.A.
Abstract: On two research trips to Norris Dam Sate Park in eastern Tennessee, we observed major differences in our ability to core trees between the winter and spring seasons. This observation led to an overarching set of research questions: does the amount of torque required to bore into a tree vary by species, elevation, tree age, or tree size? We used torque to measure the number of foot-pounds it takes for a person to core three species of trees representing the three types of wood structure: softwood (Pinus spp.), diffuse porous hardwood (Nyssa sylvatica, Marshall,), and ring porous hardwood (Quercus spp.). We quantified the degree to which the hardwood and softwood species vary based upon torque (foot-pounds) measurements. We used basic plotting and linear regression models in RStudio to explore the relationships between torque, elevation, age and DBH (diameter at breast height). We found elevation and DBH play the largest role in determining torque with oaks, but not with any other species. With an increase of 1 meter in elevation the amount of torque it takes to core an oak increases by 0.15 foot-pounds. On the other hand, with an increase in 1 centimeter in DBH the amount of torque it takes to core an oak decreases by -0.12 foot-pounds. Therefore, the easiest oak to core would be a large oak located at a lower elevation. Also, on average, using blackgums as our reference group, it takes 6.858 more foot-pounds to core into an oak and 9.175 fewer foot-pounds to core into a pine. Our study quantifies the well-established principle in dendrochronology that it requires more force to core into ring porous hardwoods than into softwood (conifer) species.
Abstract: On two research trips to Norris Dam Sate Park in eastern Tennessee, we observed major differences in our ability to core trees between the winter and spring seasons. This observation led to an overarching set of research questions: does the amount of torque required to bore into a tree vary by species, elevation, tree age, or tree size? We used torque to measure the number of foot-pounds it takes for a person to core three species of trees representing the three types of wood structure: softwood (Pinus spp.), diffuse porous hardwood (Nyssa sylvatica, Marshall,), and ring porous hardwood (Quercus spp.). We quantified the degree to which the hardwood and softwood species vary based upon torque (foot-pounds) measurements. We used basic plotting and linear regression models in RStudio to explore the relationships between torque, elevation, age and DBH (diameter at breast height). We found elevation and DBH play the largest role in determining torque with oaks, but not with any other species. With an increase of 1 meter in elevation the amount of torque it takes to core an oak increases by 0.15 foot-pounds. On the other hand, with an increase in 1 centimeter in DBH the amount of torque it takes to core an oak decreases by -0.12 foot-pounds. Therefore, the easiest oak to core would be a large oak located at a lower elevation. Also, on average, using blackgums as our reference group, it takes 6.858 more foot-pounds to core into an oak and 9.175 fewer foot-pounds to core into a pine. Our study quantifies the well-established principle in dendrochronology that it requires more force to core into ring porous hardwoods than into softwood (conifer) species.
Morning Session A, Room 354 - Animal Science
Description: The Animal Science session will feature presentations from students and faculty from multiple departments including comparative & experimental medicine, animal science, entomology & plant pathology, and forestry, wildlife, and fisheries. The inherently interdisciplinary studies presented here have examined behavior and biology using lab, field, and survey studies looking into the bedding preferences of dairy cows, pathogens in ring-necked pheasants, habitat and host dynamics in southeastern ticks, and the potential impact of parasites on manatee populations.
Jessie Kull
Graduate Student, Animal Science
Title: Preference between recycled and clean sand bedding of freestall housed Holstein dairy cows
Abstract: The objective of this study was to evaluate the preference of dairy cows for clean or recycled sand bedding. Data were collected from late-lactation dairy cows (mean days in milk = 268.1 ± 11.9 d; n=32) from August to September 2014. Cows were distributed into 4 pens and housed at a stocking density of 50% in a freestall barn. Stalls were alternatingly bedded with control or recycled sand. Unused sand served as control. Recycled sand, used once previously, was reclaimed from the settling lane of the dairy’s flushing system. Groups were exposed to treatments over 7-d. Cow behavior within a stall was categorized as lying (any recumbent position), perching (front two hooves only), and standing (all hooves). Video data was reviewed at 10-min intervals during 5 consecutive 24-h periods. Data were analyzed using the mixed procedures in SAS to assess the effect of sand bedding and behavior on proportion time in pen with observations repeated by date. Total stall occupancy was greater for control stalls (32.7 ± 1.3 %) compared to recycled sand stalls (28.6 ± 1.3 %; P = 0.004). Despite cows spending the majority of their time within a freestall lying, this behavior was greater on the control sand (P = 0.01). No preference was evident for perching (P = 0.61) or standing (P = 0.88) on either surface. There was a greater occupancy rate and proportion of time spent lying for control sand compared to recycled sand. The most common behavior was lying in the stalls, which suggested either bedding might be suitable. Caution should be used, as sand was recycled only once. This limited reclamation was still sufficient to potentially alter the composition of sand, driving the observed preference. If these changes in composition continue, then the strength of the preference may also change.
Abstract: The objective of this study was to evaluate the preference of dairy cows for clean or recycled sand bedding. Data were collected from late-lactation dairy cows (mean days in milk = 268.1 ± 11.9 d; n=32) from August to September 2014. Cows were distributed into 4 pens and housed at a stocking density of 50% in a freestall barn. Stalls were alternatingly bedded with control or recycled sand. Unused sand served as control. Recycled sand, used once previously, was reclaimed from the settling lane of the dairy’s flushing system. Groups were exposed to treatments over 7-d. Cow behavior within a stall was categorized as lying (any recumbent position), perching (front two hooves only), and standing (all hooves). Video data was reviewed at 10-min intervals during 5 consecutive 24-h periods. Data were analyzed using the mixed procedures in SAS to assess the effect of sand bedding and behavior on proportion time in pen with observations repeated by date. Total stall occupancy was greater for control stalls (32.7 ± 1.3 %) compared to recycled sand stalls (28.6 ± 1.3 %; P = 0.004). Despite cows spending the majority of their time within a freestall lying, this behavior was greater on the control sand (P = 0.01). No preference was evident for perching (P = 0.61) or standing (P = 0.88) on either surface. There was a greater occupancy rate and proportion of time spent lying for control sand compared to recycled sand. The most common behavior was lying in the stalls, which suggested either bedding might be suitable. Caution should be used, as sand was recycled only once. This limited reclamation was still sufficient to potentially alter the composition of sand, driving the observed preference. If these changes in composition continue, then the strength of the preference may also change.
Kathryn Purple
Graduate Student, Comparative & Experimental Medicine
Title: Investigating the prevalence of Histomonas meleagridis shedding by captive raised Ring-necked pheasants (Phasianus colchicus) in Pennsylvania
Abstract: Ring-necked pheasants (Phasianus colchicus) were introduced into multiple regions of Pennsylvania, USA, producing substantial hunting opportunities. Pheasants can harbor multiple pathogens in the absence of overt disease including Histomonas meleagridis, which is considered to be one of the most important pathogens for native game birds including wild turkey (Meleagris gallopavo), ruffed grouse (Bonasa umbellus), and northern bobwhite (Colinus virginianus). In addition, H. meleagridis has caused significant impacts in the commercial turkey industry. The Pennsylvania Game Commission annually raises and releases about 200,000 pheasants from 4 game farms, and as a responsible wildlife management agency, was interested the infection status of H. meleagridis in pheasants. Fifty-one pheasants from a single game farm were examined for H. meleagridis by inoculating cloacal swabs into flasks containing Dwyer’s culture media. Flasks were shipped to the University of Tennessee using a published protocol for survival of H. meleagridis in transit. Flasks were examined daily for seven days for histomonad growth. In addition, an aliquot from twenty randomly chosen flasks was used for DNA extraction and PCR targeting the internal transcribed spacer (ITS) regions of the ribosomal RNA. All flasks were culture-negative via light microscopy and DNA extract from the twenty samples was PCR-negative. These data suggest that propagated ring-necked pheasants may not always be carriers of H. meleagridis, as historically was believed. However, more research is needed to examine the frequency of H. meleagridis shedding in captive and wild pheasants, under varying conditions, and other species to further understand the eco-epidemiology of blackhead disease.
Abstract: Ring-necked pheasants (Phasianus colchicus) were introduced into multiple regions of Pennsylvania, USA, producing substantial hunting opportunities. Pheasants can harbor multiple pathogens in the absence of overt disease including Histomonas meleagridis, which is considered to be one of the most important pathogens for native game birds including wild turkey (Meleagris gallopavo), ruffed grouse (Bonasa umbellus), and northern bobwhite (Colinus virginianus). In addition, H. meleagridis has caused significant impacts in the commercial turkey industry. The Pennsylvania Game Commission annually raises and releases about 200,000 pheasants from 4 game farms, and as a responsible wildlife management agency, was interested the infection status of H. meleagridis in pheasants. Fifty-one pheasants from a single game farm were examined for H. meleagridis by inoculating cloacal swabs into flasks containing Dwyer’s culture media. Flasks were shipped to the University of Tennessee using a published protocol for survival of H. meleagridis in transit. Flasks were examined daily for seven days for histomonad growth. In addition, an aliquot from twenty randomly chosen flasks was used for DNA extraction and PCR targeting the internal transcribed spacer (ITS) regions of the ribosomal RNA. All flasks were culture-negative via light microscopy and DNA extract from the twenty samples was PCR-negative. These data suggest that propagated ring-necked pheasants may not always be carriers of H. meleagridis, as historically was believed. However, more research is needed to examine the frequency of H. meleagridis shedding in captive and wild pheasants, under varying conditions, and other species to further understand the eco-epidemiology of blackhead disease.
Rebecca Trout Fryxell
Faculty Member, Entomology & Plant Pathology
Title: Unexpected discoveries from my tick ecology research program
Abstract: In contrast to Lyme disease in the northeastern United States, the status of tick-borne diseases (TBDs) in the southeastern U.S. remains uncertain due to factors such as the introduction and identification of new diseases, the difficulty of diagnosis, habitat dynamics, warming weather trends, and changing host populations. Two TBDs with expanding case and vector distributions are ehrlichiosis (Ehrlichia bacteria transmitted by bites of infected lone star ticks) and rickettiosis (Rickettsia bacteria transmitted by bites of infected Gulf Coast and American dog ticks). Field studies to investigate habitat, host, and bacterial partitioning where these ticks and pathogens co-exist are severely lacking. Thus, there is a critical need to identify the vectors, reservoirs, habitats, and pathogens involved with transmission in order to understand the role of ticks in bacterial acquisition and transmission. Consequently, an in-depth tick ecology study was conducted in the southeast including vector incrimination studies, pathogen prevalence studies, habitat and host preference studies, and microbial community studies. This multidisciplinary project has identified two ticks of concern, several pathogenic bacteria, common hosts used for dispersal, few landscape and vegetation variables associated with tick presence, and microbial communities unique to each tick specimen (but significantly associated with key features). This presentation will cover some of the research conducted in my research program, a female tenure-track assistant professor in entomology and plant pathology, and highlight the work of several female students and faculty.
Abstract: In contrast to Lyme disease in the northeastern United States, the status of tick-borne diseases (TBDs) in the southeastern U.S. remains uncertain due to factors such as the introduction and identification of new diseases, the difficulty of diagnosis, habitat dynamics, warming weather trends, and changing host populations. Two TBDs with expanding case and vector distributions are ehrlichiosis (Ehrlichia bacteria transmitted by bites of infected lone star ticks) and rickettiosis (Rickettsia bacteria transmitted by bites of infected Gulf Coast and American dog ticks). Field studies to investigate habitat, host, and bacterial partitioning where these ticks and pathogens co-exist are severely lacking. Thus, there is a critical need to identify the vectors, reservoirs, habitats, and pathogens involved with transmission in order to understand the role of ticks in bacterial acquisition and transmission. Consequently, an in-depth tick ecology study was conducted in the southeast including vector incrimination studies, pathogen prevalence studies, habitat and host preference studies, and microbial community studies. This multidisciplinary project has identified two ticks of concern, several pathogenic bacteria, common hosts used for dispersal, few landscape and vegetation variables associated with tick presence, and microbial communities unique to each tick specimen (but significantly associated with key features). This presentation will cover some of the research conducted in my research program, a female tenure-track assistant professor in entomology and plant pathology, and highlight the work of several female students and faculty.
Heidi Wyrosdick
Graduate Student, Forestry, Wildlife & Fisheries
Title: Parasites of the Florida Manatee (Trichechus manatus latirostris)
Abstract: Manatees are an important part of Florida’s ecosystem and vital to the tourism industry which leads to extensive conservation efforts. Our study is valuable to manatee conservation because there is little known about the potential impact of parasites on manatee populations. While necropsy examination can be an important tool for studying helminths (Phyla: Nematoda and Trematoda) in the Florida manatee (Trichechus manatus latirostris), most protozoal (Phylum Protozoa) infections will be missed by this method. Centrifugal fecal flotation is the gold standard for detection of veterinary parasites shed in feces. Ethyl acetate sedimentation is the most effective technique for specifically detecting trematode ova in feces. Two previous studies have reported parasites from fecal analyses of the Florida manatee. The goal of our study is to survey parasites in the Florida manatee using two fecal examination techniques. To date, centrifugal fecal flotation and ethyl acetate sedimentation were conducted on 11 fecal samples collected from live manatees during health assessments in Crystal River, Florida and 9 fecal samples from manatees during necropsy at the Marine Mammal Pathobiology Laboratory. Adult parasite specimens in good condition were collected for specific identification. Thus far, we have identified several parasites consistent with previous reports. The results of these examinations will be presented.
Abstract: Manatees are an important part of Florida’s ecosystem and vital to the tourism industry which leads to extensive conservation efforts. Our study is valuable to manatee conservation because there is little known about the potential impact of parasites on manatee populations. While necropsy examination can be an important tool for studying helminths (Phyla: Nematoda and Trematoda) in the Florida manatee (Trichechus manatus latirostris), most protozoal (Phylum Protozoa) infections will be missed by this method. Centrifugal fecal flotation is the gold standard for detection of veterinary parasites shed in feces. Ethyl acetate sedimentation is the most effective technique for specifically detecting trematode ova in feces. Two previous studies have reported parasites from fecal analyses of the Florida manatee. The goal of our study is to survey parasites in the Florida manatee using two fecal examination techniques. To date, centrifugal fecal flotation and ethyl acetate sedimentation were conducted on 11 fecal samples collected from live manatees during health assessments in Crystal River, Florida and 9 fecal samples from manatees during necropsy at the Marine Mammal Pathobiology Laboratory. Adult parasite specimens in good condition were collected for specific identification. Thus far, we have identified several parasites consistent with previous reports. The results of these examinations will be presented.
Morning Session A, Room 434 - Chemistry
Description: The Chemistry session will present students involved in materials, environmental, analytical, and theoretical research. A unique combination of pure and applied topics will be presented, showing how this core physical science is pushing boundaries into topics like nanofluidics and ion transport using next-generation materials like carbon nanotubes, the bridge between theoretical and experimental models of helium crystals, the application of mass spectrometry to quantify nutrient availability in thawing arctic soils, and the development of kinetic models for real-time monitoring of gas phase reactions of hydrogen.
Michelle Aranha
Graduate Student, Chemical & Biomolecular Engineering
Title: Water and ion transport through carbon nanotubes
Abstract: Carbon nanotubes (CNTs) are promising materials with a vast range of potential applications, especially in water treatment and nanofluidic devices. As a single example, CNTs can be easily embedded into lipid membranes and can be used as effective biomimetic devices. Water has unique properties and an understanding of the interaction between water and carbon nanotubes is key to the development of many of these devices. The confinement of water in carbon nanotubes as compared to bulk water is known to produce some remarkable features, such as lower number of hydrogen bonds, increased lifetime of hydrogen bonds, layered structure of water under confinement, reduced density and viscosity, and an increased proton mobility in 1-D water chains. One of the more exciting results of water under confinement is the high slip lengths that result at high flow rates, which are conducive to ultrafiltration and nanofiltration. Similar high water flow rates along with selective ion transport is an important feature of ion channels in living organisms; however, experimental analysis to study these complex ion channels is a real challenge. On the other hand, carbon nanotubes can be easily functionalized to obtain ion selectivity and high flow rates and, as mentioned previously, can be inserted into lipid membranes making them simple alternatives to study the mechanism of transport in ion channels. We investigate the structural and dynamic characteristics of water and ion (NaCl solution) transport through charged and uncharged CNTs using MD simulations in this study spanning a large number of CNT diameters. The goal is to integrate fast water flow with ion selectivity through modulation of pore sizes, surface charges, and electric fields. This can not only help understand biological processes, but also help design advanced nanofluidic devices in the future.
Abstract: Carbon nanotubes (CNTs) are promising materials with a vast range of potential applications, especially in water treatment and nanofluidic devices. As a single example, CNTs can be easily embedded into lipid membranes and can be used as effective biomimetic devices. Water has unique properties and an understanding of the interaction between water and carbon nanotubes is key to the development of many of these devices. The confinement of water in carbon nanotubes as compared to bulk water is known to produce some remarkable features, such as lower number of hydrogen bonds, increased lifetime of hydrogen bonds, layered structure of water under confinement, reduced density and viscosity, and an increased proton mobility in 1-D water chains. One of the more exciting results of water under confinement is the high slip lengths that result at high flow rates, which are conducive to ultrafiltration and nanofiltration. Similar high water flow rates along with selective ion transport is an important feature of ion channels in living organisms; however, experimental analysis to study these complex ion channels is a real challenge. On the other hand, carbon nanotubes can be easily functionalized to obtain ion selectivity and high flow rates and, as mentioned previously, can be inserted into lipid membranes making them simple alternatives to study the mechanism of transport in ion channels. We investigate the structural and dynamic characteristics of water and ion (NaCl solution) transport through charged and uncharged CNTs using MD simulations in this study spanning a large number of CNT diameters. The goal is to integrate fast water flow with ion selectivity through modulation of pore sizes, surface charges, and electric fields. This can not only help understand biological processes, but also help design advanced nanofluidic devices in the future.
Ashleigh Barnes
Graduate Student, Chemistry
Title: Development and evaluation of a perturbative treatment of three-body interactions in HCP solid He-4: A quantum Monte Carlo study
Abstract: The properties of hexagonal close packed (hcp) solid 4He are dominated by large atomic zero point motions, which make the primary contribution to the solid’s low-temperature Debye-Waller (DW) factor. It is proposed that an accurate understanding of these zero point motions requires consideration of three-body interactions, which can significantly increase computational cost. We utilize quantum Monte Carlo (QMC) methods and either a 2-body or a 2+3-body potential energy function to calculate the ground state energy and DW factors for hcp 4He at T = 0 K in crystals with molar volumes ranging from 2.5 cm3 to 21.3 cm3. In addition, crystals with distorted lattices are investigated at the lowest density. We perform two sets of QMC simulations. One set of simulations incorporates the three-body interactions into the solid’s potential energy function for the entire simulation; the other set of simulations treats the three-body interactions as a small perturbation, or correction, to the two-body potential energy function. Theoretical equations of state for each set of simulations are reported and compared to experimental data, and we observe that simulations accounting for three-body interactions show improved agreement with experiment over two-body calculations. At this stage, only a negligible difference in the calculated properties is observed between the two treatments of the three-body interactions in both ideal and distorted lattices, indicating that the more computationally efficient perturbative approach may be sufficient for an accurate description of the system. None of our simulations of ideal systems reveal significant anisotropy in the DW factors for atomic motion parallel or perpendicular to the crystal’s basal plane; this is in contrast to recent experimental findings of Blackburn et al. where substantial anisotropy of this type was observed at temperatures near T = 0 K.
Abstract: The properties of hexagonal close packed (hcp) solid 4He are dominated by large atomic zero point motions, which make the primary contribution to the solid’s low-temperature Debye-Waller (DW) factor. It is proposed that an accurate understanding of these zero point motions requires consideration of three-body interactions, which can significantly increase computational cost. We utilize quantum Monte Carlo (QMC) methods and either a 2-body or a 2+3-body potential energy function to calculate the ground state energy and DW factors for hcp 4He at T = 0 K in crystals with molar volumes ranging from 2.5 cm3 to 21.3 cm3. In addition, crystals with distorted lattices are investigated at the lowest density. We perform two sets of QMC simulations. One set of simulations incorporates the three-body interactions into the solid’s potential energy function for the entire simulation; the other set of simulations treats the three-body interactions as a small perturbation, or correction, to the two-body potential energy function. Theoretical equations of state for each set of simulations are reported and compared to experimental data, and we observe that simulations accounting for three-body interactions show improved agreement with experiment over two-body calculations. At this stage, only a negligible difference in the calculated properties is observed between the two treatments of the three-body interactions in both ideal and distorted lattices, indicating that the more computationally efficient perturbative approach may be sufficient for an accurate description of the system. None of our simulations of ideal systems reveal significant anisotropy in the DW factors for atomic motion parallel or perpendicular to the crystal’s basal plane; this is in contrast to recent experimental findings of Blackburn et al. where substantial anisotropy of this type was observed at temperatures near T = 0 K.
Mallory Ladd
Graduate Student, Energy Science & Engineering
Title: Development and evaluation of a dual separation, high-resolution, nano-ESI MS/MS approach for low molecular weight dissolved soil organic matter
Abstract: Elucidating the chemical composition of low molecular weight (LMW) dissolved soil organic matter (DOM) is critical to understanding the feedbacks between carbon and nitrogen cycling, soil microbial communities, and environmental change. Comprehensively profiling a complex mixture of small molecules is particularly challenging in soils however because of the wide-ranging physicochemical properties of the various analytes, high fluxes of those analytes leading to consistently low concentrations, and the abundance of potentially interfering inorganic species. Here, we describe an analytical approach that leverages both reversed-phase (RP) and hydrophilic interaction chromatography (HILIC), nano-electrospray ionization (nanoESI), and high-resolution mass spectrometry to broadly characterize LMW DOM from two varying soil types. Soil pore-water samples from a high-Arctic, continuous permafrost, polygonal tundra soil on the northern coastal plain of Alaska, and sediment salt extracts from a soil near Rifle, CO were collected. A preliminary evaluation of the ESI behavior of the samples and a set of LMW organic standards was carried out using direct infusion ESI-MS/MS. Separations were performed using two stationary phases, 5µm C18 (Kinetex) and 5µm polymer-based zwitterionic ZIC-pHILIC (EMD Millipore), that were pressure packed into 100µm i.d. x 15cm pulled fused-silica nanoESI columns. Initial MS1 scans followed by collision-induced dissociation (CID) MS/MS at multiple collision energies were carried out on an Orbitrap Velos Pro mass spectrometer (ThermoScientific) in positive and negative ion modes. By coupling two contrasting chromatographies with high-resolution nanoESI-MS/MS, a broader range of LMW DOM compounds could be separated and characterized by their accurate m/z signals and fragmentation patterns with enhanced sensitivity and a greater dynamic range. This analytical platform was evaluated using two contrasting soil types, and can be leveraged in the future to help inform our understanding of DOM transformations over time, and organic nutrient availability, and how these processes may impact agricultural practices, bioremediation, and process-scale climate models.
Abstract: Elucidating the chemical composition of low molecular weight (LMW) dissolved soil organic matter (DOM) is critical to understanding the feedbacks between carbon and nitrogen cycling, soil microbial communities, and environmental change. Comprehensively profiling a complex mixture of small molecules is particularly challenging in soils however because of the wide-ranging physicochemical properties of the various analytes, high fluxes of those analytes leading to consistently low concentrations, and the abundance of potentially interfering inorganic species. Here, we describe an analytical approach that leverages both reversed-phase (RP) and hydrophilic interaction chromatography (HILIC), nano-electrospray ionization (nanoESI), and high-resolution mass spectrometry to broadly characterize LMW DOM from two varying soil types. Soil pore-water samples from a high-Arctic, continuous permafrost, polygonal tundra soil on the northern coastal plain of Alaska, and sediment salt extracts from a soil near Rifle, CO were collected. A preliminary evaluation of the ESI behavior of the samples and a set of LMW organic standards was carried out using direct infusion ESI-MS/MS. Separations were performed using two stationary phases, 5µm C18 (Kinetex) and 5µm polymer-based zwitterionic ZIC-pHILIC (EMD Millipore), that were pressure packed into 100µm i.d. x 15cm pulled fused-silica nanoESI columns. Initial MS1 scans followed by collision-induced dissociation (CID) MS/MS at multiple collision energies were carried out on an Orbitrap Velos Pro mass spectrometer (ThermoScientific) in positive and negative ion modes. By coupling two contrasting chromatographies with high-resolution nanoESI-MS/MS, a broader range of LMW DOM compounds could be separated and characterized by their accurate m/z signals and fragmentation patterns with enhanced sensitivity and a greater dynamic range. This analytical platform was evaluated using two contrasting soil types, and can be leveraged in the future to help inform our understanding of DOM transformations over time, and organic nutrient availability, and how these processes may impact agricultural practices, bioremediation, and process-scale climate models.
Harkiran Dhah
Graduate Student, Chemistry
Title: Beyond the Double Harmonic Approximation in Acquiring HNO Absorption Intensities
Abstract: Theoretical kinetic experiments are necessary to understand the experiments carried out at the University of Wyoming which work with a hydrogen matrix infused with dopant molecules at low temperatures. The dopant molecule of interest for our theoretical studies is the NO radical, which through photochemical reactions form HNO. Kinetic analysis is needed to provide information about the role that the hydrogen matrix plays in promoting or inhibiting the H + NO reaction. This analysis can be carried out by monitoring the HNO concentration as a function of time using in situ infrared absorption spectroscopy, but first theoretical studies are needed to obtain accurate absorption intensities for HNO. Over two decades have passed since the most recent study of the HNO absorption intensities; this study used a double harmonic treatment based on molecular orbital calculations that employed, by today’s standard, very small basis sets. Our work shows that the assumptions established by the double harmonic approximation fail to provide accurate behaviors of energies and dipole moments of HNO. This is in part because the unusually long and weak HN bond in HNO leads to substantial anharmonic behavior. Improvements on calculating more accurate absorption intensities are in the works by employing modern basis sets and by going beyond the double harmonic approximation.
Abstract: Theoretical kinetic experiments are necessary to understand the experiments carried out at the University of Wyoming which work with a hydrogen matrix infused with dopant molecules at low temperatures. The dopant molecule of interest for our theoretical studies is the NO radical, which through photochemical reactions form HNO. Kinetic analysis is needed to provide information about the role that the hydrogen matrix plays in promoting or inhibiting the H + NO reaction. This analysis can be carried out by monitoring the HNO concentration as a function of time using in situ infrared absorption spectroscopy, but first theoretical studies are needed to obtain accurate absorption intensities for HNO. Over two decades have passed since the most recent study of the HNO absorption intensities; this study used a double harmonic treatment based on molecular orbital calculations that employed, by today’s standard, very small basis sets. Our work shows that the assumptions established by the double harmonic approximation fail to provide accurate behaviors of energies and dipole moments of HNO. This is in part because the unusually long and weak HN bond in HNO leads to substantial anharmonic behavior. Improvements on calculating more accurate absorption intensities are in the works by employing modern basis sets and by going beyond the double harmonic approximation.
Morning Session A, Room 639 - Biomedical Engineering & Neuroscience
Description: The Biomedical Engineering & Neuroscience session will feature presentations from undergraduate and graduate students from multiple departments including Mechanical, Aeroscpace & Biomedical Engineering, and Psychology. These studies use biomedical, computational, and immunohistochemical techniques to address important questions concerning medical devices, osteoarthritis, and social behaviors during stress.
Taylor Schlotman
Graduate Student, Mechanical, Aerospace, Biomedical Engineering
Title: Decreasing Knee Joint Contact Loads via Toe-In Gait for Patients with Knee Osteoarthritis
Abstract: INTRODUCTION: Toe-in gait modification has been shown to reduce the first peak external knee adduction moment (KAM) in patients with medial knee osteoarthritis (OA), but the effect on knee loads is unknown. Investigating knee joint contact loads under toe-in gait conditions may characterize this modification in terms of creating targeted intervention strategies. We hypothesized that toe-in gait reduces the relative medial knee load in subjects with knee OA. METHODS: Eight subjects with knee OA walked with normal and toe-in gait (10 steps for normal gait at baseline, 10 steps for toe-in gait after 6-week training, and 10 steps for toe-in gait at one month follow-up). Subject-specific muscle-actuated dynamic simulations were created for each subject to estimate joint contact loads. To determine the changes in knee loads from normal to toe-in gait, the joint contact forces and moments were computed and analyzed using the Joint Reaction Analysis tool in OpenSim. RESULTS: At 27% of stance, where the first peak external KAM occurs, all subjects showed a decrease of 18.7% (p<0.01) on average in the relative medial knee load for toe-in gait compared to normal gait following 6-weeks of training, and a 25.3% decrease (p<0.01) at one-month follow-up. This decrease reflects a shift in this load away from the diseased medial compartment towards the healthy lateral, as there were no significant differences (p>0.01) in compressive and shear contact forces nor extension and internal rotation contact moments following 6-week training or one-month follow-up. CONCLUSION: This study found that toe-in gait modification can decrease knee contact loads in patients with medial knee OA. With retention after one-month, these results show the efficacy of toe-in gait to improve knee function for patients with knee OA. Finally, these results add to an increasing body of knowledge suggesting a need to determine optimized subject-specific gait modification strategies.
Abstract: INTRODUCTION: Toe-in gait modification has been shown to reduce the first peak external knee adduction moment (KAM) in patients with medial knee osteoarthritis (OA), but the effect on knee loads is unknown. Investigating knee joint contact loads under toe-in gait conditions may characterize this modification in terms of creating targeted intervention strategies. We hypothesized that toe-in gait reduces the relative medial knee load in subjects with knee OA. METHODS: Eight subjects with knee OA walked with normal and toe-in gait (10 steps for normal gait at baseline, 10 steps for toe-in gait after 6-week training, and 10 steps for toe-in gait at one month follow-up). Subject-specific muscle-actuated dynamic simulations were created for each subject to estimate joint contact loads. To determine the changes in knee loads from normal to toe-in gait, the joint contact forces and moments were computed and analyzed using the Joint Reaction Analysis tool in OpenSim. RESULTS: At 27% of stance, where the first peak external KAM occurs, all subjects showed a decrease of 18.7% (p<0.01) on average in the relative medial knee load for toe-in gait compared to normal gait following 6-weeks of training, and a 25.3% decrease (p<0.01) at one-month follow-up. This decrease reflects a shift in this load away from the diseased medial compartment towards the healthy lateral, as there were no significant differences (p>0.01) in compressive and shear contact forces nor extension and internal rotation contact moments following 6-week training or one-month follow-up. CONCLUSION: This study found that toe-in gait modification can decrease knee contact loads in patients with medial knee OA. With retention after one-month, these results show the efficacy of toe-in gait to improve knee function for patients with knee OA. Finally, these results add to an increasing body of knowledge suggesting a need to determine optimized subject-specific gait modification strategies.
Rachel Thompson
Graduate Student, Mechanical, Aerospace, Biomedical Engineering
Title: Evaluation of Muscle Force Changes in Healthy People and Patients with Osteoarthritis during Stationary Cycling with Pedal Modifications
Abstract: INTRODUCTION: Osteoarthritis (OA) is a degenerative joint disease destroying the quality of life for roughly 27 million U.S. adults. Cycling is considered an alternative exercise for people with OA, but there is a lack of scientific knowledge characterizing benefits for these individuals. The purpose of this study was to evaluate muscle force changes for subjects with and without knee OA during cycling using different pedal conditions. We hypothesized that lateral pedal wedge modifications of 5° and 10° would change the mean muscle forces in both cohorts compared to neutral (0°). METHODS: We evaluated two females, one with knee OA (height 1.8 m; mass 99.55 kg) and another without knee OA (height 1.7 m; mass 93.18 kg). Data was collected in three cycling pedal conditions: 1) neutral, 2) 5° lateral pedal wedge, and 3) 10° lateral pedal wedge. Simulations were created using OpenSim. Musculoskeletal models were scaled based on skin marker positions. Inverse kinematics was used to derive joint kinematics from experimental data. Static optimization was carried out to estimate muscle forces to generate the inverse dynamics moments. We evaluated our hypothesis regarding the differences in mean muscle forces in the 3 pedal conditions by conducting a two-sample t-test at a significance level of 0.01. RESULTS AND DISCUSSION: The subject with knee OA decreased (p<0.01) mean muscle forces by 53% (Iliacus) and 47% (Psoas) in the 5° lateral pedal wedge condition compared to neutral. The healthy subject increased mean muscle forces by 357% (Quadratus Femoris) and 784% (Adductor Magnus) in the lateral pedal wedge conditions. There were fewer significant differences in the subject with knee OA; this could be due to unique neuromusculoskeletal adaptations in the subject analyzed. Future work is needed to investigate changes in muscle forces and joint contact loads contributing to knee OA in a larger sample size.
Abstract: INTRODUCTION: Osteoarthritis (OA) is a degenerative joint disease destroying the quality of life for roughly 27 million U.S. adults. Cycling is considered an alternative exercise for people with OA, but there is a lack of scientific knowledge characterizing benefits for these individuals. The purpose of this study was to evaluate muscle force changes for subjects with and without knee OA during cycling using different pedal conditions. We hypothesized that lateral pedal wedge modifications of 5° and 10° would change the mean muscle forces in both cohorts compared to neutral (0°). METHODS: We evaluated two females, one with knee OA (height 1.8 m; mass 99.55 kg) and another without knee OA (height 1.7 m; mass 93.18 kg). Data was collected in three cycling pedal conditions: 1) neutral, 2) 5° lateral pedal wedge, and 3) 10° lateral pedal wedge. Simulations were created using OpenSim. Musculoskeletal models were scaled based on skin marker positions. Inverse kinematics was used to derive joint kinematics from experimental data. Static optimization was carried out to estimate muscle forces to generate the inverse dynamics moments. We evaluated our hypothesis regarding the differences in mean muscle forces in the 3 pedal conditions by conducting a two-sample t-test at a significance level of 0.01. RESULTS AND DISCUSSION: The subject with knee OA decreased (p<0.01) mean muscle forces by 53% (Iliacus) and 47% (Psoas) in the 5° lateral pedal wedge condition compared to neutral. The healthy subject increased mean muscle forces by 357% (Quadratus Femoris) and 784% (Adductor Magnus) in the lateral pedal wedge conditions. There were fewer significant differences in the subject with knee OA; this could be due to unique neuromusculoskeletal adaptations in the subject analyzed. Future work is needed to investigate changes in muscle forces and joint contact loads contributing to knee OA in a larger sample size.
Sofy Weisenberg
Graduate Student, Mechanical, Aerospace, Biomedical Engineering
Title: Optimization of Ventricular Catheter Design Using High-Performance Computing
Abstract: Cerebrospinal fluid (CSF) shunts are fully implantable medical devices that are used to treat patients suffering from conditions characterized by elevated intracranial pressure, such as hydrocephalus. One of the primary causes of CSF shunt failure is mechanical obstruction of the ventricular catheter, a component of the shunt system implanted directly into the brain's ventricular system. This study aims to characterize the CSF flow through ventricular catheters via a 3-dimensional computational fluid dynamics (CFD) model. This fully-parametrized model allowed for exploration of the catheter’s geometric design features, with the goal of reducing the incidence of catheter obstruction. As the first step towards this goal, a design optimization study was performed with the objective of achieving a uniform flow rate distribution among the catheter inlet holes. To perform this study, the CFD model was coupled with an optimization framework, and a large number of simulations were analyzed using high-performance computing to determine the optimal design for the target flow performance. This optimization study advances the field of CSF shunt design by providing systematically derived correlations between the catheter’s geometric parameters and CSF flow through the catheter.
Abstract: Cerebrospinal fluid (CSF) shunts are fully implantable medical devices that are used to treat patients suffering from conditions characterized by elevated intracranial pressure, such as hydrocephalus. One of the primary causes of CSF shunt failure is mechanical obstruction of the ventricular catheter, a component of the shunt system implanted directly into the brain's ventricular system. This study aims to characterize the CSF flow through ventricular catheters via a 3-dimensional computational fluid dynamics (CFD) model. This fully-parametrized model allowed for exploration of the catheter’s geometric design features, with the goal of reducing the incidence of catheter obstruction. As the first step towards this goal, a design optimization study was performed with the objective of achieving a uniform flow rate distribution among the catheter inlet holes. To perform this study, the CFD model was coupled with an optimization framework, and a large number of simulations were analyzed using high-performance computing to determine the optimal design for the target flow performance. This optimization study advances the field of CSF shunt design by providing systematically derived correlations between the catheter’s geometric parameters and CSF flow through the catheter.
Sahba Seddighi
Undergraduate Student, Neuroscience, Psychology
Title: Cellular mechanisms by which social status alters behavioral responses to stress
Abstract: Understanding the cellular mechanisms that control resistance and vulnerability to stress is an important step toward identifying novel targets for the prevention and treatment of stress-related mental illness. Dominant and subordinate animals have been shown to exhibit different behavioral and physiological responses to stress, with dominants often showing stress resistance and subordinates showing stress vulnerability. We have previously found that dominant hamsters exhibit reduced social avoidance following social defeat stress compared to subordinate hamsters, although the extent to which stress resistance in dominants generalizes to non-social stressors is unknown. In this study dominant, subordinate, and control male Syrian hamsters were exposed to acute restraint stress for 30 minutes. In one cohort of animals, brains were collected for c-Fos immunohistochemistry following restraint stress. In a second cohort, blood samples were collected immediately following restraint and animals were tested for anxiety-like behavior in an open field arena 24 hours later. Preliminary data indicate that restrained animals exhibited increased plasma cortisol compared to non-restrained controls. Also, restraint stress increased the number of c-Fos-positive cells in several brain regions including the infralimbic cortex, prelimbic cortex, medial amygdala, and paraventricular nucleus of the hypothalamus. Analysis of c-Fos immunoreactivity, plasma cortisol, and anxiety-like behavior in dominant and subordinate animals is ongoing. This project will address whether resistance to social defeat stress in dominant hamsters generalizes to restraint stress and extend existing literature on the domain-general vs. domain-specific nature of stress resilience.
Abstract: Understanding the cellular mechanisms that control resistance and vulnerability to stress is an important step toward identifying novel targets for the prevention and treatment of stress-related mental illness. Dominant and subordinate animals have been shown to exhibit different behavioral and physiological responses to stress, with dominants often showing stress resistance and subordinates showing stress vulnerability. We have previously found that dominant hamsters exhibit reduced social avoidance following social defeat stress compared to subordinate hamsters, although the extent to which stress resistance in dominants generalizes to non-social stressors is unknown. In this study dominant, subordinate, and control male Syrian hamsters were exposed to acute restraint stress for 30 minutes. In one cohort of animals, brains were collected for c-Fos immunohistochemistry following restraint stress. In a second cohort, blood samples were collected immediately following restraint and animals were tested for anxiety-like behavior in an open field arena 24 hours later. Preliminary data indicate that restrained animals exhibited increased plasma cortisol compared to non-restrained controls. Also, restraint stress increased the number of c-Fos-positive cells in several brain regions including the infralimbic cortex, prelimbic cortex, medial amygdala, and paraventricular nucleus of the hypothalamus. Analysis of c-Fos immunoreactivity, plasma cortisol, and anxiety-like behavior in dominant and subordinate animals is ongoing. This project will address whether resistance to social defeat stress in dominant hamsters generalizes to restraint stress and extend existing literature on the domain-general vs. domain-specific nature of stress resilience.
Afternoon Oral Presentations
Afternoon Session B, Room 118 - Chemical Engineering
Description: Presenters in the Chemical Engineering session will explore research topics related to environmental sustainability. Two presentations will discuss the progress toward using cost effective non-precious metals as electrodes for membrane fuel cells. We will also learn about tuning the polymerization method for biodegradable lactide-based plastics and using solid iron to activate persulfate oxidation of organic contaminants for environmental remediation applications.
Laura Matzek
Graduate Student, Civil & Environmental Engineering
Title: Unique Persulfate-based Advanced Oxidation for Environmental Contaminant Destruction: Implications for Ciprofloxacin Degradation
Abstract: Recent attention has been given to new methods for activated persulfate degradation of recalcitrant environmental pollutants in aqueous systems. Enhanced techniques to maintain persulfate and activator concentrations during these reactions will improve resource utilization and lead to greater contaminant removal. It is hypothesized that the iron level needed to sustain an activated persulfate degradation reaction can be minimized through the use of solid iron, and that persulfate activation can be controlled with current applied to the solid iron. Experiments were performed in two stages. The first part of this research is to demonstrate controlled persulfate activation by a solid iron rod, with and without applied current. Unlike countless studies in this area, these experiments were completed without analyte, to achieve a fundamental understanding of the basic activation mechanisms. Results from these experiments showed that solid iron provides a continuous source of ferrous iron into solution for sustained persulfate activation. Here, the persulfate activation follows zero-order kinetics and is controlled by the surface area or applied current. Iron utilization improves with increasing current, possibly due to ferrous iron regeneration at the cathode. These results demonstrate that persulfate can be activated with much lower levels of iron than typically used in iron-activated persulfate research. The second stage of this project demonstrates the efficacy of solid iron-activated persulfate to remove recalcitrant environmental contaminants. Experiments were completed using the solid iron/persulfate system to degrade the fluoroquinoline antibiotic ciprofloxacin. The solid iron activated persulfate successfully removed ciprofloxacin from solution and complete de-fluorination was achieved. By-products are currently being analyzed, as well as total organic carbon. Overall, research findings provide an enhanced understanding of persulfate activation by solid iron. The results also provide a promising technique for sustained iron-persulfate reactions, which minimizes the introduction of iron into solution while achieving successful organic removal.
Abstract: Recent attention has been given to new methods for activated persulfate degradation of recalcitrant environmental pollutants in aqueous systems. Enhanced techniques to maintain persulfate and activator concentrations during these reactions will improve resource utilization and lead to greater contaminant removal. It is hypothesized that the iron level needed to sustain an activated persulfate degradation reaction can be minimized through the use of solid iron, and that persulfate activation can be controlled with current applied to the solid iron. Experiments were performed in two stages. The first part of this research is to demonstrate controlled persulfate activation by a solid iron rod, with and without applied current. Unlike countless studies in this area, these experiments were completed without analyte, to achieve a fundamental understanding of the basic activation mechanisms. Results from these experiments showed that solid iron provides a continuous source of ferrous iron into solution for sustained persulfate activation. Here, the persulfate activation follows zero-order kinetics and is controlled by the surface area or applied current. Iron utilization improves with increasing current, possibly due to ferrous iron regeneration at the cathode. These results demonstrate that persulfate can be activated with much lower levels of iron than typically used in iron-activated persulfate research. The second stage of this project demonstrates the efficacy of solid iron-activated persulfate to remove recalcitrant environmental contaminants. Experiments were completed using the solid iron/persulfate system to degrade the fluoroquinoline antibiotic ciprofloxacin. The solid iron activated persulfate successfully removed ciprofloxacin from solution and complete de-fluorination was achieved. By-products are currently being analyzed, as well as total organic carbon. Overall, research findings provide an enhanced understanding of persulfate activation by solid iron. The results also provide a promising technique for sustained iron-persulfate reactions, which minimizes the introduction of iron into solution while achieving successful organic removal.
Samantha Medina
Undergraduate Student, Materials Science & Engineering
Title: Electrochemical Evaluation of Non-precious Metal Catalysts for Fuel Cell Applications
Abstract: Proton exchange membrane fuel cell (PEMFC) and anion exchange membrane fuel cells (AEMFCs) are devices that generate electricity by means of a chemical reaction. Both PEMFCs and AEMFCs provide an environmentally friendly alternative to oil-derived fuels with higher efficiency than that of the combustion engine. They can be used to power cars, and for other portable applications. However, one of the major disadvantages of PEMFCs and AEMFCs is the high cost associated with using platinum group metals (PGMs) as the catalyst for the reactions taking place on both the anode and cathode electrodes. Replacing platinum at the cathode and anode electrodes with non-precious group metal (NPGM) catalysts would significantly decrease the cost of fuel cells. The purpose of our research is to determine the optimal parameters affecting the catalytic performance of NPGM catalyst for the oxygen reduction reaction (ORR) taking place at the cathode. We synthesized NPGM catalysts using various Cu and Fe salts, nitrogen precursors (nitrogen rich sources) along with a carbon support. The catalyst initially show very low ORR activity, but after thermal activation under inert atmosphere the catalytic activity was significantly improved. Electrochemical activity was measured by the rotating ring disk electrode (RRDE) technique in both alkaline and acidic electrolytes. The iron sulfate catalyst heat-treated at 900oC showed the best catalytic activity in acidic and alkaline environments. The iron sulfate catalyst performance was tested in both PEM and AEM fuel cell.
Abstract: Proton exchange membrane fuel cell (PEMFC) and anion exchange membrane fuel cells (AEMFCs) are devices that generate electricity by means of a chemical reaction. Both PEMFCs and AEMFCs provide an environmentally friendly alternative to oil-derived fuels with higher efficiency than that of the combustion engine. They can be used to power cars, and for other portable applications. However, one of the major disadvantages of PEMFCs and AEMFCs is the high cost associated with using platinum group metals (PGMs) as the catalyst for the reactions taking place on both the anode and cathode electrodes. Replacing platinum at the cathode and anode electrodes with non-precious group metal (NPGM) catalysts would significantly decrease the cost of fuel cells. The purpose of our research is to determine the optimal parameters affecting the catalytic performance of NPGM catalyst for the oxygen reduction reaction (ORR) taking place at the cathode. We synthesized NPGM catalysts using various Cu and Fe salts, nitrogen precursors (nitrogen rich sources) along with a carbon support. The catalyst initially show very low ORR activity, but after thermal activation under inert atmosphere the catalytic activity was significantly improved. Electrochemical activity was measured by the rotating ring disk electrode (RRDE) technique in both alkaline and acidic electrolytes. The iron sulfate catalyst heat-treated at 900oC showed the best catalytic activity in acidic and alkaline environments. The iron sulfate catalyst performance was tested in both PEM and AEM fuel cell.
Lauren Brown
Graduate Student, Chemistry
Title: Enhancing Lactide Polymerization Control through the use of Redox-active Catalysts
Abstract: In recent years, bioplastics have become a highly sought-after alternative to conventional petrochemical-based plastics due to their biodegradability and derivatization from renewable resources. Specifically, polylactic acid (PLA) has shown tremendous promise for a variety of applications including medical and packaging products. The utilization of lactide, the dimeric cyclic ester of lactic acid, was found to readily produce high molecular weight PLA via ring-opening polymerization (ROP). ROP can be conducted by several methods, but one that has shown tremendous potential is employment of transition-metal-based catalysts. By using these catalysts, lactide can be polymerized in a controlled fashion and incorporated into advanced architectures. In order to examine potential methods of polymerization control, we chose to study redox-switchable catalysts that can alter polymerization behavior based on their ligand oxidation state. Previous studies have shown that the electronic nature of a catalyst may alter the rate of polymerization as well as the reactivity of individual monomers. To advance fundamental understanding within this field, we examined the proximity effects of redox-active moiety placement relative to the active site during lactide polymerization. Toward this end, a group 4 transition-metal-based catalyst was designed containing a redox-active moiety in close proximity to the active metal center and was compared to a catalyst containing its redox-active substituents farther away from the active polymerization site. Through these studies, we will demonstrate that—(1) polymerization control is enhanced by close placement of the redox-active moiety to the active center and (2) the catalyst's polymerization behavior is strongly dependent on the environment in which the catalyst is oxidized or reduced. Furthermore, we provide strong evidence that this unique polymerization behavior is due to an in situ switch in catalyst geometry, which is the first report of this phenomenon.
Abstract: In recent years, bioplastics have become a highly sought-after alternative to conventional petrochemical-based plastics due to their biodegradability and derivatization from renewable resources. Specifically, polylactic acid (PLA) has shown tremendous promise for a variety of applications including medical and packaging products. The utilization of lactide, the dimeric cyclic ester of lactic acid, was found to readily produce high molecular weight PLA via ring-opening polymerization (ROP). ROP can be conducted by several methods, but one that has shown tremendous potential is employment of transition-metal-based catalysts. By using these catalysts, lactide can be polymerized in a controlled fashion and incorporated into advanced architectures. In order to examine potential methods of polymerization control, we chose to study redox-switchable catalysts that can alter polymerization behavior based on their ligand oxidation state. Previous studies have shown that the electronic nature of a catalyst may alter the rate of polymerization as well as the reactivity of individual monomers. To advance fundamental understanding within this field, we examined the proximity effects of redox-active moiety placement relative to the active site during lactide polymerization. Toward this end, a group 4 transition-metal-based catalyst was designed containing a redox-active moiety in close proximity to the active metal center and was compared to a catalyst containing its redox-active substituents farther away from the active polymerization site. Through these studies, we will demonstrate that—(1) polymerization control is enhanced by close placement of the redox-active moiety to the active center and (2) the catalyst's polymerization behavior is strongly dependent on the environment in which the catalyst is oxidized or reduced. Furthermore, we provide strong evidence that this unique polymerization behavior is due to an in situ switch in catalyst geometry, which is the first report of this phenomenon.
Diana Orozco-Gallo
Graduate Student, Chemical & Biomedical Engineering
Title: Multi-scale Modeling and Comprehensive Study of PEM Fuel Cells Catalyst Layers
Abstract: PEMFCs catalyst layers are compose of three elements: porous carbon to provide electron transport, ionomer to provide protonic transport and catalyst to facilitate the reduction or oxidation reactions. The oxygen reduction reaction (ORR) is the most studied reaction due to its sluggish kinetics with respect to Hydrogen Oxidation Reaction (HOR). The replacement of Pt with non-precious-metal-based catalysts (NPMCs) for the ORR is considered the key to enhance a sustainable and cost-effective power generation in PEMFCs. In order to reduce the Pt loading we should either enhance better Pt mass activity or developing NPMCs with high performance for ORR. The complexity of the NPMCs systems under study lies in the unknown nature of the active site where is difficult to identify structural and electronic parameters based on most characterization techniques. Many questions arise when compared with Pt-based systems such as: Which elements Pt and NPMCs layers have in common? How can we identify and distinguish between different catalyst layers? What makes one metal more suitable than another? What specific catalyst layer composition and structure are optimal? How do we correlate energetics, structure and transport issues? Modeling catalyst layers is a complicated task because we need to take into account the phenomena in different time and size scales: (i) heterogeneous electrochemical reactions in the nanoscale; (ii) proton, electron and gases transport in the mesoscale; and (iii) gases and water transport through membranes and porous media in the macroscale. The first step then, is to identify and classify the main macroscopic parameters that affect the performance by using complex and adequate experimental data sets and reduce the degrees of freedom for fitting. Once the parameters are identify, we move in the right scale, physics and computational methodology that the macroscopic results point out in order to complete the picture and resolve the unknowns.
Abstract: PEMFCs catalyst layers are compose of three elements: porous carbon to provide electron transport, ionomer to provide protonic transport and catalyst to facilitate the reduction or oxidation reactions. The oxygen reduction reaction (ORR) is the most studied reaction due to its sluggish kinetics with respect to Hydrogen Oxidation Reaction (HOR). The replacement of Pt with non-precious-metal-based catalysts (NPMCs) for the ORR is considered the key to enhance a sustainable and cost-effective power generation in PEMFCs. In order to reduce the Pt loading we should either enhance better Pt mass activity or developing NPMCs with high performance for ORR. The complexity of the NPMCs systems under study lies in the unknown nature of the active site where is difficult to identify structural and electronic parameters based on most characterization techniques. Many questions arise when compared with Pt-based systems such as: Which elements Pt and NPMCs layers have in common? How can we identify and distinguish between different catalyst layers? What makes one metal more suitable than another? What specific catalyst layer composition and structure are optimal? How do we correlate energetics, structure and transport issues? Modeling catalyst layers is a complicated task because we need to take into account the phenomena in different time and size scales: (i) heterogeneous electrochemical reactions in the nanoscale; (ii) proton, electron and gases transport in the mesoscale; and (iii) gases and water transport through membranes and porous media in the macroscale. The first step then, is to identify and classify the main macroscopic parameters that affect the performance by using complex and adequate experimental data sets and reduce the degrees of freedom for fitting. Once the parameters are identify, we move in the right scale, physics and computational methodology that the macroscopic results point out in order to complete the picture and resolve the unknowns.
Afternoon Session B, Room 235 - Psychology
Description: The psychology session with feature presentations on executive function in early childhood development, mother- infant interactions during motor skill transitions, protocols for analyzing Jordanian burial rituals, and infant social development. These studies use a wide range of techniques including functional near-infrared spectroscopy, behavioral video observation, and statistical analysis to better understand social, physical, and cultural development.
Anastasia Kerr-German
Graduate Student, Psychology
Title: A dynamic field theory approach to the development of attention in early childhood
Abstract: Measures of executive function (EF) in early childhood are predictive of academic achievement and various quality of life outcomes in adulthood and includes abilities such as attentional control, goal direct behavior, working memory, and inhibition. Despite the critical nature of EF research, there is little clarity regarding the mechanisms and processes that are involved in the development of these abilities. A recent neural-process approach using dynamic field theory (DFT) put forth by Buss and Spencer (2014) demonstrates how a simple dimensional attention mechanism can explain the behavioral and neural data associated with the development of flexible attention. The goal of the current project was to generalize this theory to explain the development of multiple aspects of attention including selectivity and priming. I present a set of behavioral and hemodynamic simulations that explains the co-development of these aspects of attention. The model predicts that both selective and flexible attention develop through a common mechanism that drives the formation of long-range connectivity between frontal and temporal cortex. In addition, simulations of a priming task suggest that attentional stability may mediate flexibility and selectivity in early childhood. Despite a common developmental mechanism that drives changes in these diverse aspects of attention, the model predicts divergence in cortical activation between these tasks at different points in development. These differences in cortical activation suggest that different attention tasks rely upon different aspects of the frontal-temporal-parietal network implemented by the model. I collected functional near-infrared spectroscopy (fNIRS) and behavioral data (utilizing E-Prime software) from 3- and 4-year-olds, which provides additional support for the model. The developmental of this modeling framework lays the foundation for developing theory-driven interventions that can target the underlying neural systems involved in the development of EF.
Abstract: Measures of executive function (EF) in early childhood are predictive of academic achievement and various quality of life outcomes in adulthood and includes abilities such as attentional control, goal direct behavior, working memory, and inhibition. Despite the critical nature of EF research, there is little clarity regarding the mechanisms and processes that are involved in the development of these abilities. A recent neural-process approach using dynamic field theory (DFT) put forth by Buss and Spencer (2014) demonstrates how a simple dimensional attention mechanism can explain the behavioral and neural data associated with the development of flexible attention. The goal of the current project was to generalize this theory to explain the development of multiple aspects of attention including selectivity and priming. I present a set of behavioral and hemodynamic simulations that explains the co-development of these aspects of attention. The model predicts that both selective and flexible attention develop through a common mechanism that drives the formation of long-range connectivity between frontal and temporal cortex. In addition, simulations of a priming task suggest that attentional stability may mediate flexibility and selectivity in early childhood. Despite a common developmental mechanism that drives changes in these diverse aspects of attention, the model predicts divergence in cortical activation between these tasks at different points in development. These differences in cortical activation suggest that different attention tasks rely upon different aspects of the frontal-temporal-parietal network implemented by the model. I collected functional near-infrared spectroscopy (fNIRS) and behavioral data (utilizing E-Prime software) from 3- and 4-year-olds, which provides additional support for the model. The developmental of this modeling framework lays the foundation for developing theory-driven interventions that can target the underlying neural systems involved in the development of EF.
Sabrina Thurman
Graduate Student, Psychology
Title: Dynamic Changes in Mother-Infant Interaction During Motor Skill Transitions in the First Two Years
Abstract: Advancements in infant motor skills trigger changes in parent-infant interactions, exploration and play behaviors (Campos et al., 2000). Sensitive mothers respond to changing infant skills by increasing stimulatory behaviors to promote learning and discovery (Belsky et al., 1980). Here, we aim to understand these dyadic changes as they occur and unfold as a function of infants’ motor skill development during 10-minute free-play sessions. Thirteen dyads were observed twice monthly in a laboratory setting, from 6 to 17 months. The 11 X 12 ft. room contained toys, colorful 1-sq.-ft. foam tiles, a couch, and small stairs. Changes in gross motor skills were captured with Touwen’s Assessment of Motor Behavior. Using video recordings sampled at 30s intervals in Noldus Observer, we derived the following variables: mother-infant distance; infants’ postural activities (e.g., sitting, creeping on all fours, walking); mothers’ supporting or directing behaviors; and interactive play behaviors. Interactive play behaviors of infants significantly increased when infants learned to creep (p<.029), but remained the same when learning to walk. Mothers did not show changes in their total interactive play, but did significantly increase interactions with their infants when infants became expert creepers (p<.011). Measures of distance between mother and infant were also clearly modulated by the postural-locomotor progression of the infants. Before locomotion emerged, mothers spent the most time directing their infants’ behaviors, but this declined as infants learned to creep (p<.037). Our results provide evidence that mother-infant interactions during free-play change continuously throughout motor skill transitions, and also within sessions as infants adopt different postural and locomotor skills to explore the room and objects within.
Abstract: Advancements in infant motor skills trigger changes in parent-infant interactions, exploration and play behaviors (Campos et al., 2000). Sensitive mothers respond to changing infant skills by increasing stimulatory behaviors to promote learning and discovery (Belsky et al., 1980). Here, we aim to understand these dyadic changes as they occur and unfold as a function of infants’ motor skill development during 10-minute free-play sessions. Thirteen dyads were observed twice monthly in a laboratory setting, from 6 to 17 months. The 11 X 12 ft. room contained toys, colorful 1-sq.-ft. foam tiles, a couch, and small stairs. Changes in gross motor skills were captured with Touwen’s Assessment of Motor Behavior. Using video recordings sampled at 30s intervals in Noldus Observer, we derived the following variables: mother-infant distance; infants’ postural activities (e.g., sitting, creeping on all fours, walking); mothers’ supporting or directing behaviors; and interactive play behaviors. Interactive play behaviors of infants significantly increased when infants learned to creep (p<.029), but remained the same when learning to walk. Mothers did not show changes in their total interactive play, but did significantly increase interactions with their infants when infants became expert creepers (p<.011). Measures of distance between mother and infant were also clearly modulated by the postural-locomotor progression of the infants. Before locomotion emerged, mothers spent the most time directing their infants’ behaviors, but this declined as infants learned to creep (p<.037). Our results provide evidence that mother-infant interactions during free-play change continuously throughout motor skill transitions, and also within sessions as infants adopt different postural and locomotor skills to explore the room and objects within.
Melissa Meador
Undergraduate Student, Psychology
Title: Bioarchaeological Protocols and Analysis for Islamic period remains at 'Ayn Gharandal in southern Jordan
Abstract: Bioarchaeologists face challenges in countries such as Jordan because authorities may forbid the removal of human remains from archaeological sites and often limit the use of laboratory analyses on the remains. In Jordan, these rules are especially important when burials are related to a Muslim population. Nevertheless, the examination of human remains is integral for answering questions related to the health of local populations, burial practices, ritual, and nutritional intake. As a result of these challenges, the 2015 season of the ‘Ayn Gharandal Archaeological Project (AGAP) developed on-site analyses that maximized data while still respecting Jordanian cultural and religious mores. ‘Ayn Gharandal is a Late Roman through Islamic period site in southern Jordan. The burials at the site took place after the Roman period structures were abandoned, at which time the site was reused extensively as a burial ground for several hundred years. The burials at ‘Ayn Gharandal date to the Islamic period, as indicated by the position of the human remains facing Mecca and recent Carbon 14 analysis from burial shrouds. Overall, the human remains are preserved fairly well because of the dry local climate. As a result, the overall bioarchaeological research goals for the site integrate archaeological excavation of the burials as well as on-site non-invasive sample collection in order to answer the following research questions: (1) determining if the population was nomadic, (2) determining any possible relations between interred individuals, (3) identifying the lifeways and health of the population, and (4) any previously undocumented developments in burial techniques as well as indicators of a system of hierarchy among the cist burials. In order to present the ongoing AGAP bioarchaeological research, this paper will give a brief history of the site and the human burials, describe the bioarchaeological research protocol within the cultural and religious context of modern Jordan, and examine in closer detail human burials that I excavated during the 2015 season.
Abstract: Bioarchaeologists face challenges in countries such as Jordan because authorities may forbid the removal of human remains from archaeological sites and often limit the use of laboratory analyses on the remains. In Jordan, these rules are especially important when burials are related to a Muslim population. Nevertheless, the examination of human remains is integral for answering questions related to the health of local populations, burial practices, ritual, and nutritional intake. As a result of these challenges, the 2015 season of the ‘Ayn Gharandal Archaeological Project (AGAP) developed on-site analyses that maximized data while still respecting Jordanian cultural and religious mores. ‘Ayn Gharandal is a Late Roman through Islamic period site in southern Jordan. The burials at the site took place after the Roman period structures were abandoned, at which time the site was reused extensively as a burial ground for several hundred years. The burials at ‘Ayn Gharandal date to the Islamic period, as indicated by the position of the human remains facing Mecca and recent Carbon 14 analysis from burial shrouds. Overall, the human remains are preserved fairly well because of the dry local climate. As a result, the overall bioarchaeological research goals for the site integrate archaeological excavation of the burials as well as on-site non-invasive sample collection in order to answer the following research questions: (1) determining if the population was nomadic, (2) determining any possible relations between interred individuals, (3) identifying the lifeways and health of the population, and (4) any previously undocumented developments in burial techniques as well as indicators of a system of hierarchy among the cist burials. In order to present the ongoing AGAP bioarchaeological research, this paper will give a brief history of the site and the human burials, describe the bioarchaeological research protocol within the cultural and religious context of modern Jordan, and examine in closer detail human burials that I excavated during the 2015 season.
Kimberly Bress
Undergraduate Student, Psychology
Title: Developmental Cognitive Neuroscience at the Birkbeck Babylab
Abstract: During the summer after my second undergraduate semester at the University of Tennessee, I served as a research intern at the University of London Birkbeck Babylab. Under the direction of researchers Katarina Begus and Carina de Klerk, I assisted with three research projects. Two of these projects involved the use of functional near infrared spectroscopy (fNIRS), a novel brain imaging technology, to investigate social development in human infants. While the first project investigated infants’ ability to imitate and mimic, the second investigated infants’ understanding of social relationships. Specifically, this study focused on the importance of the temporal parietal junction and superior temporal sulcus in the conceptualization of social interactions. Using developmental neuroscience to investigate the mechanisms of social processing has important implications for understanding the emergence of social processing disorders. Through this independently organized research experience, I gained a valuable insight regarding the research principles of developmental cognitive neuroscience, in addition to experience with essential brain imaging technologies.
Abstract: During the summer after my second undergraduate semester at the University of Tennessee, I served as a research intern at the University of London Birkbeck Babylab. Under the direction of researchers Katarina Begus and Carina de Klerk, I assisted with three research projects. Two of these projects involved the use of functional near infrared spectroscopy (fNIRS), a novel brain imaging technology, to investigate social development in human infants. While the first project investigated infants’ ability to imitate and mimic, the second investigated infants’ understanding of social relationships. Specifically, this study focused on the importance of the temporal parietal junction and superior temporal sulcus in the conceptualization of social interactions. Using developmental neuroscience to investigate the mechanisms of social processing has important implications for understanding the emergence of social processing disorders. Through this independently organized research experience, I gained a valuable insight regarding the research principles of developmental cognitive neuroscience, in addition to experience with essential brain imaging technologies.
Afternoon Session B, Room 354 - Plant Pathology & Agricultural Sciences
Description: The Plant Pathology and Agricultural Sciences session will feature presentations on the economic and ecological impact of three prevalent soybean pests including the herbivorous kudzu bug, the fungal pathogens that cause soybean rust, and the frogeye leaf spot blight. Data presented will include greenhouse, field, and national-scale monitoring of the organisms’ progression, as well as the effectiveness of biocides and biological controls on managing these agricultural pests.
Kadie Britt
Graduate Student, Entomology & Plant Pathology
Title: Ecology and Phenology of Kudzu Bug in East Tennessee
Abstract: The kudzu bug, Megacopta cribraria, a non-native, invasive species from Asia, was first discovered in the U.S. in 2009 in several northeastern counties in Georgia. It has since spread to numerous other states, including Tennessee. The kudzu bug causes agricultural, urban, and health-related concerns. This talk will provide information on ecology and life history of kudzu bug in Tennessee. Primary host plants for kudzu bugs include soybean and kudzu. To determine whether kudzu bugs find other plants suitable for reproduction and development, choice and no-choice tests were conducted. Four main plants were evaluated: kudzu, soybean, bush honeysuckle, and ragweed. In 2014, three locations in Knox Co. were selected with three kudzu sites established at each location. These three locations were visited weekly from May to November. Five sweep-net samples were taken from kudzu at each site, and kudzu bug adults and nymphs (stages 1-5) were counted and recorded. Kudzu bugs were present on kudzu in Knox County until early November in 2014 and late November in 2015. 2014 results will be analyzed and presented, as well as summaries of ongoing 2015 studies to better assess life history, phenology, and the role of natural enemies to enhance management of this pest.
Abstract: The kudzu bug, Megacopta cribraria, a non-native, invasive species from Asia, was first discovered in the U.S. in 2009 in several northeastern counties in Georgia. It has since spread to numerous other states, including Tennessee. The kudzu bug causes agricultural, urban, and health-related concerns. This talk will provide information on ecology and life history of kudzu bug in Tennessee. Primary host plants for kudzu bugs include soybean and kudzu. To determine whether kudzu bugs find other plants suitable for reproduction and development, choice and no-choice tests were conducted. Four main plants were evaluated: kudzu, soybean, bush honeysuckle, and ragweed. In 2014, three locations in Knox Co. were selected with three kudzu sites established at each location. These three locations were visited weekly from May to November. Five sweep-net samples were taken from kudzu at each site, and kudzu bug adults and nymphs (stages 1-5) were counted and recorded. Kudzu bugs were present on kudzu in Knox County until early November in 2014 and late November in 2015. 2014 results will be analyzed and presented, as well as summaries of ongoing 2015 studies to better assess life history, phenology, and the role of natural enemies to enhance management of this pest.
Heather Kelly
Faculty Member, Entomology & Plant Pathology
Title: From Select Agent to an Established Pathogen: The Response to Phakopsora pachyrhizi (Soybean Rust) in North America
Abstract: The pathogen causing soybean rust, Phakopsora pachyrhizi, was first described in Japan in 1902. The disease was important in the Eastern Hemisphere for many decades before the fungus was reported in Hawaii in 1994, which was followed by reports from countries in Africa and South America. In 2004, P. pachyrhizi was confirmed in Louisiana, making it the first report in the continental United States. Based on yield losses from countries in Asia, Africa, and South America, it was clear that this pathogen could have a major economic impact on the yield of 30 million ha of soybean in the United States. The response by agencies within the United States Department of Agriculture, industry, soybean check-off boards, and universities was immediate and complex. The impacts of some of these activities will be described in this presentation. The net result has been that the once dreaded disease, which caused substantial losses in other parts of the world, is now better understood and effectively managed in the United States. The disease continues to be monitored yearly for changes in spatial and temporal distribution so that soybean growers can continue to benefit by knowing where soybean rust is occurring during the growing season.
Abstract: The pathogen causing soybean rust, Phakopsora pachyrhizi, was first described in Japan in 1902. The disease was important in the Eastern Hemisphere for many decades before the fungus was reported in Hawaii in 1994, which was followed by reports from countries in Africa and South America. In 2004, P. pachyrhizi was confirmed in Louisiana, making it the first report in the continental United States. Based on yield losses from countries in Asia, Africa, and South America, it was clear that this pathogen could have a major economic impact on the yield of 30 million ha of soybean in the United States. The response by agencies within the United States Department of Agriculture, industry, soybean check-off boards, and universities was immediate and complex. The impacts of some of these activities will be described in this presentation. The net result has been that the once dreaded disease, which caused substantial losses in other parts of the world, is now better understood and effectively managed in the United States. The disease continues to be monitored yearly for changes in spatial and temporal distribution so that soybean growers can continue to benefit by knowing where soybean rust is occurring during the growing season.
Binbin Lin
Postdoc, Entomology & Plant Pathology
Title: Fitness and competition studies of QoI resistant and sensitive Cercospora sojina isolates, the causal agent of frogeye leaf spot
Abstract: Frogeye leaf spot (FLS), caused by Cercospora sojina, is a foliar disease affecting soybean that causes substantial economic losses if not properly managed. Quinone outside inhibitor (QoI) fungicides are used to manage FLS, but C. sojina isolates have developed resistance. Currently, most soybean fields contain both QoI- resistant and -sensitive isolates, therefore a better understanding of the biology and aggressiveness of isolates is important. In greenhouse studies, spore suspensions (≈1×105 conidia/ml) prepared from QoI-resistant and -sensitive isolates in different ratios were used to inoculate soybean plants (FLS susceptible ‘Blackhawk’, V4 growth stage). Plants were treated 24 h before inoculation at the label rate with no fungicide (water only), Quadris (azoxystrobin), or Quadris Top (azoxystrobin + difenoconazole), with 12 replicates per treatment. Results were: 1) Disease severity increased as the proportion of QoI-resistant isolates increased, indicating that QoI-resistant isolates are more aggressive across all treatments; 2) Quadris inhibited FLS caused by QoI-sensitive isolates only, and when the proportion of QoI resistance was ≤ 10%; 3) Quadris Top provided more effective control of FLS by reducing symptoms and delaying disease development. Fitness parameters of QoI-resistant and -sensitive isolates were (i) mycelial growth and sporulation capacity, (ii) conidial germination and growth inhibition on fungicide-amended media. As a group, no significant differences in the mean values of these fitness parameters were observed between resistant and sensitive isolates, except for sporulation capacity and growth inhibition. In addition, conidial germination assay results were compared to qPCR results to confirm the proportion of QoI resistant isolates recovered from inoculated plants. Resistant isolates dominated the population in all mixed inoculation tests except for the water treatment. These results indicate there are differences in QoI resistant and sensitive C. sojina isolates in-planta that will influence effective disease management of FLS.
Abstract: Frogeye leaf spot (FLS), caused by Cercospora sojina, is a foliar disease affecting soybean that causes substantial economic losses if not properly managed. Quinone outside inhibitor (QoI) fungicides are used to manage FLS, but C. sojina isolates have developed resistance. Currently, most soybean fields contain both QoI- resistant and -sensitive isolates, therefore a better understanding of the biology and aggressiveness of isolates is important. In greenhouse studies, spore suspensions (≈1×105 conidia/ml) prepared from QoI-resistant and -sensitive isolates in different ratios were used to inoculate soybean plants (FLS susceptible ‘Blackhawk’, V4 growth stage). Plants were treated 24 h before inoculation at the label rate with no fungicide (water only), Quadris (azoxystrobin), or Quadris Top (azoxystrobin + difenoconazole), with 12 replicates per treatment. Results were: 1) Disease severity increased as the proportion of QoI-resistant isolates increased, indicating that QoI-resistant isolates are more aggressive across all treatments; 2) Quadris inhibited FLS caused by QoI-sensitive isolates only, and when the proportion of QoI resistance was ≤ 10%; 3) Quadris Top provided more effective control of FLS by reducing symptoms and delaying disease development. Fitness parameters of QoI-resistant and -sensitive isolates were (i) mycelial growth and sporulation capacity, (ii) conidial germination and growth inhibition on fungicide-amended media. As a group, no significant differences in the mean values of these fitness parameters were observed between resistant and sensitive isolates, except for sporulation capacity and growth inhibition. In addition, conidial germination assay results were compared to qPCR results to confirm the proportion of QoI resistant isolates recovered from inoculated plants. Resistant isolates dominated the population in all mixed inoculation tests except for the water treatment. These results indicate there are differences in QoI resistant and sensitive C. sojina isolates in-planta that will influence effective disease management of FLS.
Afternoon Session B, Room 434 - Nuclear Engineering & Chemistry
Description: The Nuclear Engineering and Chemistry session will feature presentations that; (1) Investigate the synthesis and characterization of second generation titanium catalysts with a single site, automically dispersed and targeted connectivity to the active site with altered geometries for ease of accessibility, (2) probe a UQ technique that can differentiate sources of prediction errors to support high-confidence calibration assessments of nuclear power plants, (3) use inductively coupled plasma mass spectrometry to determine the main trace elements present in the DIII-D fusion energy project and, (4) use laser based diagnostics to assess plasma surface interactions in tungsten for the ITER project where tungsten will be the diverter.
Lena Elenchin
Graduate Student, Chemistry
Title: Synthesis and Characterization of Single Site Heterogeneous Titanium Catalysts for Selective Oxidation
Abstract: Porous heterogeneous catalysts are of continuing interest in catalysis because of their easy separation from the reactants and products. The Barnes group has developed a synthetic methodology for producing silicate matrices with isolated, atomically dispersed, identical cationic metal centers [1]. This methodology utilizes the building block approach and what we will refer to as the method of sequential additions. This synthetic strategy is similar to molecular imprinting, but does not require the use of a traditional templating agent. In the building block approach, the catalysis metal is used as a template for the matrix to build around, but is not removed from the matrix after synthesis. This methodology can be used to target metal connectivities (2, 3, or 4 linkages) to the matrix in a tetrahedral geometry. These catalysts were shown to be effective in the oxidation of phenols to benzoquinones and in the epoxidation of cyclohexene to 1,2-epoxycyclohexane. The primary focus of this research is to synthesize and characterize a second generation of catalysts that will be single site, atomically dispersed, with a targeted connectivity to the silicate matrix, like the first generation, but these catalysts will have altered geometries, such as square planar, for a more accessible active site. By opening the active site, this family of catalysts should, in theory, be more active than first generation catalysts. Several characterization techniques are used to compare and contrast first and second generation catalysts; NMR, gravimetric analysis (determine connectivity), FTIR, XAS (XANES/EXAFS), DRUV, and catalytic activity. XAS data was collected on beam line X19A at National Synchrotron Light Source at Brookhaven National Lab. Reference [1] Clark, J.C., Barnes, C.E. Chem. Mater. 19, 3212 (2007).
Abstract: Porous heterogeneous catalysts are of continuing interest in catalysis because of their easy separation from the reactants and products. The Barnes group has developed a synthetic methodology for producing silicate matrices with isolated, atomically dispersed, identical cationic metal centers [1]. This methodology utilizes the building block approach and what we will refer to as the method of sequential additions. This synthetic strategy is similar to molecular imprinting, but does not require the use of a traditional templating agent. In the building block approach, the catalysis metal is used as a template for the matrix to build around, but is not removed from the matrix after synthesis. This methodology can be used to target metal connectivities (2, 3, or 4 linkages) to the matrix in a tetrahedral geometry. These catalysts were shown to be effective in the oxidation of phenols to benzoquinones and in the epoxidation of cyclohexene to 1,2-epoxycyclohexane. The primary focus of this research is to synthesize and characterize a second generation of catalysts that will be single site, atomically dispersed, with a targeted connectivity to the silicate matrix, like the first generation, but these catalysts will have altered geometries, such as square planar, for a more accessible active site. By opening the active site, this family of catalysts should, in theory, be more active than first generation catalysts. Several characterization techniques are used to compare and contrast first and second generation catalysts; NMR, gravimetric analysis (determine connectivity), FTIR, XAS (XANES/EXAFS), DRUV, and catalytic activity. XAS data was collected on beam line X19A at National Synchrotron Light Source at Brookhaven National Lab. Reference [1] Clark, J.C., Barnes, C.E. Chem. Mater. 19, 3212 (2007).
Anjali Nair
Graduate Student, Nuclear Engineering
Title: High Confidence Uncertainty Quantification Techniques for Online Sensor Calibration Methods in Nuclear Power Plants
Abstract: High-value and safety-critical systems rely on accurate and reliable measurements for monitoring and control. In the US nuclear industry, sensor calibration is maintained through periodic assessment and recalibration as prescribed in the plant license. Current US regulations require periodic calibration every 18-24 months; this can be a critical path item during refueling outages and contributes to worker radiation exposure and O&M costs [1]. Apart from being an optimization issue, the current approach may not be applicable to future reactor designs and the advanced sensor technologies that they employ [2]. The last decade has seen the rise of online calibration assessment, through online monitoring (OLM), as a promising solution for nuclear plant instrumentation health management. OLM utilizes highly accurate prediction models to assess the calibration of sensors while the plant is operating. This approach supports the extension or elimination of periodic recalibration intervals. The US Nuclear Regulatory Commission (NRC) requires a measure of the ‘reliability’ of OLM calibration assessment results that can fit into the current regulatory structure [3, 4]. This reliability boils down to the uncertainty in the OLM system, including measurement noise, prediction uncertainty, and model inadequacy. The ability to quantify the various elements of uncertainty provides the technical structure satisfying regulatory requirements. This research investigates a UQ technique that can differentiate sources of prediction errors to support high-confidence calibration assessment [5]. Confidence bounds on sensor performance are modeled with stationary components (measurement noise and model inadequacy) and nonstationary components (sensor degradation). A Bayesian Inference model (BIM) is used in conjunction with genetic algorithms to characterize the stationary components of the prediction error under normal and faulted conditions, including steady state and dynamic system operation. When the sensor performance (OLM model residuals) exceed the Uncertainty bounds of the stationary errors, the sensor is said to be out of calibration.
Abstract: High-value and safety-critical systems rely on accurate and reliable measurements for monitoring and control. In the US nuclear industry, sensor calibration is maintained through periodic assessment and recalibration as prescribed in the plant license. Current US regulations require periodic calibration every 18-24 months; this can be a critical path item during refueling outages and contributes to worker radiation exposure and O&M costs [1]. Apart from being an optimization issue, the current approach may not be applicable to future reactor designs and the advanced sensor technologies that they employ [2]. The last decade has seen the rise of online calibration assessment, through online monitoring (OLM), as a promising solution for nuclear plant instrumentation health management. OLM utilizes highly accurate prediction models to assess the calibration of sensors while the plant is operating. This approach supports the extension or elimination of periodic recalibration intervals. The US Nuclear Regulatory Commission (NRC) requires a measure of the ‘reliability’ of OLM calibration assessment results that can fit into the current regulatory structure [3, 4]. This reliability boils down to the uncertainty in the OLM system, including measurement noise, prediction uncertainty, and model inadequacy. The ability to quantify the various elements of uncertainty provides the technical structure satisfying regulatory requirements. This research investigates a UQ technique that can differentiate sources of prediction errors to support high-confidence calibration assessment [5]. Confidence bounds on sensor performance are modeled with stationary components (measurement noise and model inadequacy) and nonstationary components (sensor degradation). A Bayesian Inference model (BIM) is used in conjunction with genetic algorithms to characterize the stationary components of the prediction error under normal and faulted conditions, including steady state and dynamic system operation. When the sensor performance (OLM model residuals) exceed the Uncertainty bounds of the stationary errors, the sensor is said to be out of calibration.
Lauren Finney
Undergraduate Student, Chemistry
Title: Analysis of ICPMS Accuracy for Fusion Energy Advancement
Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) is an innovative technique that has revolutionized the way trace elements are detected. ICP-MS is one of few techniques capable of performing both elemental and isotopic analysis and with accuracy far beyond most competing techniques (parts per trillion in solution). This is used in the research surrounding the DIII-D fusion energy project, which is a device that confines extremely hot plasma (greater than 10 million degrees Celsius) allowing deuterium fuel particles to fuse. Particles eroded from the vessel walls are able to reach the plasma as impurities that remove much needed heat from the fuel particles. These impurities need to be identified and the relative amounts of each type of impurity quantified. The presentation will cover the studies done at The University of Tennessee at Knoxville (UTK) in determining the main trace elements and isotopes, specifically tungsten (W), present in DIII-D. W is a very important material for fusion research because it has the highest melting point of any metal, low erosion, and low retention of H isotopes. Some of the tests being run are to determine which process best extracts the trace metals from the graphite collector probes used to catch the contaminants inside DIII-D. The current procedures tested are using tape to remove the materials collected on the surface and dissolving this in acidic solution. Various grades of graphite considered for use for the collector probes are also being analyzed to assess the prevalence of minor impurities. The main focus is to push the limits of ICP-MS to measure the absolute amounts of the different isotopes ofW present on the collector probes. The discoveries are compared to previous analysis done on the materials to improve the precision and determine the most efficient technique to use. This research uses advanced methods to further improve our understanding of fusion energy technology.
Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) is an innovative technique that has revolutionized the way trace elements are detected. ICP-MS is one of few techniques capable of performing both elemental and isotopic analysis and with accuracy far beyond most competing techniques (parts per trillion in solution). This is used in the research surrounding the DIII-D fusion energy project, which is a device that confines extremely hot plasma (greater than 10 million degrees Celsius) allowing deuterium fuel particles to fuse. Particles eroded from the vessel walls are able to reach the plasma as impurities that remove much needed heat from the fuel particles. These impurities need to be identified and the relative amounts of each type of impurity quantified. The presentation will cover the studies done at The University of Tennessee at Knoxville (UTK) in determining the main trace elements and isotopes, specifically tungsten (W), present in DIII-D. W is a very important material for fusion research because it has the highest melting point of any metal, low erosion, and low retention of H isotopes. Some of the tests being run are to determine which process best extracts the trace metals from the graphite collector probes used to catch the contaminants inside DIII-D. The current procedures tested are using tape to remove the materials collected on the surface and dissolving this in acidic solution. Various grades of graphite considered for use for the collector probes are also being analyzed to assess the prevalence of minor impurities. The main focus is to push the limits of ICP-MS to measure the absolute amounts of the different isotopes ofW present on the collector probes. The discoveries are compared to previous analysis done on the materials to improve the precision and determine the most efficient technique to use. This research uses advanced methods to further improve our understanding of fusion energy technology.
Guinevere Shaw
Graduate Student, Energy Science & Engineering
Title: Preliminary Development of a Quantitative Method to Detect He in W using Laser Based Diagnostics
Abstract: The impact of energetic helium (He) and hydrogen ions onto plasma facing components (PFCs) have the potential to cause physical sputtering, chemical erosion, sub-surface bubble formation, hydrogen trapping and trapping, surface segregation and topology changes, among other issues that can degrade the performance of the divertor and first wall. Tungsten (W) will be the divertor in ITER, and is a prime candidate material for divertor and PFC applications in future fusion reactors. Our group is investigating the use of laser based diagnostics to assess plasma surface interactions in tungsten. More specifically, Laser Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Mass Spectroscopy (LAMS) are being used to develop a quantitative method to determine He concentration in W following gas implantation. LIBS is a surface characterization technique in which the laser ablates a small volume off of the surface, and subsequently characterizes the surface concentration through the use of optical emission spectroscopy (OES). LAMS also uses a laser to ablate a fixed volume of surface material, but then pumps the ablated vapor into a Quadrupole Mass Spectrometer (QMS). We report the results of LIBS measurements of He ion implanted W, which definitively identify the sub-surface helium, as well as a controlled assessment of the ablated volume per laser shot, as a function of laser operating parameters. We will also present the initial results from LAMS characterization focused on developing a calibration curve to quantify the LIBS measurements.
Abstract: The impact of energetic helium (He) and hydrogen ions onto plasma facing components (PFCs) have the potential to cause physical sputtering, chemical erosion, sub-surface bubble formation, hydrogen trapping and trapping, surface segregation and topology changes, among other issues that can degrade the performance of the divertor and first wall. Tungsten (W) will be the divertor in ITER, and is a prime candidate material for divertor and PFC applications in future fusion reactors. Our group is investigating the use of laser based diagnostics to assess plasma surface interactions in tungsten. More specifically, Laser Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Mass Spectroscopy (LAMS) are being used to develop a quantitative method to determine He concentration in W following gas implantation. LIBS is a surface characterization technique in which the laser ablates a small volume off of the surface, and subsequently characterizes the surface concentration through the use of optical emission spectroscopy (OES). LAMS also uses a laser to ablate a fixed volume of surface material, but then pumps the ablated vapor into a Quadrupole Mass Spectrometer (QMS). We report the results of LIBS measurements of He ion implanted W, which definitively identify the sub-surface helium, as well as a controlled assessment of the ablated volume per laser shot, as a function of laser operating parameters. We will also present the initial results from LAMS characterization focused on developing a calibration curve to quantify the LIBS measurements.