Monday, March 28 - Friday, April 1Abstract: Strength and Failure of eggshells Eggshells can be easily broken by striking them at a local point. However, breaking it by squeezing the egg with a distriuted load, such as using one's hand to do so, is nearly impossible. Although the shell is a very thin porous calcium carbonate structure, its compressive resistance is an interesting feature. In this study, a new insight on these mechanical properties is provided through a series of experiments of compression of various kinds of bird eggs along their long-axis. Failure applied force scales with the thickness of the shell reaching loads upwards of five-thousand Newtons for ostrich eggs. Failure occurs by axial splitting parallel to the loading direction, spaced by a characteristic length. The spacing is the result of radial tensile stresses that develop from the applied compressive traction. These observations were then compared with calculations executed on a finite element model of an ovoide volume under compression using a maximum tensile stress criterion.
Friday, April 8 - Tuesday, April 12Abstract: The purpose of this study is to examine how military-connected adolescents overcome their challenges in navigating military and civilian worlds of home and school. Military-connected students are an underserved, at-risk population in United States public schools. Currently, more than 90 percent of the 1.2 million military-connected dependents in the United States are enrolled in civilian public schools (De Pedro, Astor, Gilreath, Benbenishty, & Esqueda, 2013). However, researchers know very little about their school experiences. What researchers do know is that children of military Service members face several challenges that may related to negative academic outcomes: learning gaps, social-emotional and behavioral challenges associated with high mobility rates and parent deployment (Astor, Jacobson, & Benbenishty, 2012; Milburn & Lightfoot, 2013). This study seeks to inform research and practice communities in creating highly supportive environments for military-connected adolescents in civilian schools.
Thursday, April 7 - Sunday, January 10Abstract: This paper assesses the impact of candidate race on vote shares in elections to the Brazilian Chamber of Deputies. Researchers broadly agree that contemporary Brazilian society is characterized by entrenched racial stratification, yet the importance of race in Brazil's political arena remains debated. I argue that that candidate race is a significant determinant of Brazilian electoral outcomes. This contrasts with the prominent argument that elected officials in Brazil are disproportionately white because of their resource advantages. My findings confirm the importance of campaign resources, but also imply that candidate race influences electoral outcomes. Moreover, when I disaggregate the Afro-Brazilian racial category, I find that self-identified Brown candidates do substantially better than self-identified Black candidates. These results imply that racial stratification extends to Brazil's highest political bodies and suggest promising avenues for future research on Brazilian race politics.
New Orleans, LA
Sunday, February 21 - Friday, February 26Abstract: Dissolved organic copper-binding ligands were examined on the U.S. GEOTRACES zonal transect in the Eastern Tropical South Pacific from Peru to Tahiti. All samples were measured using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV), the bulk in duplicate titrations at a single analytical window (5 ÂµM) of the added ligand salicylaldoxime (SA). A subset of samples was analyzed using multiple competition strengths (1, 2.5, 5, 10, and 25 ÂµM added SA). Titration data was processed using newly available software for single and multiple analytical window data. Equilibration tests conducted at the various analytical windows showed no significant differences in ligand concentration and binding strength between overnight vs. 15-30 minutes equilibration time. Samples analyzed at a single window reveal excess strong ligands in the coastal region over the Oxygen Minimum Zone with a conditional stability constant (logK) around 14. Multiple competition strengths of the added ligand enabled the detection of up to three classes of copper-binding ligands, with conditional stability constants ranging from 8.6-16.0, and high concentrations of the weaker ligands throughout the water column. Analysis is ongoing and this presentation will summarize the status of this unique data set.
Palm Springs Convention Center, Palm Springs, California
Thursday, February 18 - Sunday, February 21Abstract: Keywords: autonomic pain response; crossover pilot study; galvanic skin response; heart rate variability; non-invasive vagus nerve stimulation Introduction We investigated non-invasive vagus nerve stimulation (nVNS) vs sham far lateral neck stimulation (ShS) stimulation to determine if there are measurable effects on the autonomic nervous system, based on 1) the subjective experience of pain as measured by the verbal numeric rating scale (VNRS), and 2) the autonomic response to pain as measured by heart rate variability (HRV) and galvanic skin response (GSR). Materials and Methods 7 healthy male subjects were enrolled in a crossover study comparing nVNS versus ShS. All subjects underwent initial neurosensory testing with a MEDOC TSA II unit to determine heat pain thresholds and tolerances using the method of limits. Heart rate variability (HRV) and galvanic skin response (GSR) were measured using a BIOPAC system. Subjects first underwent ShS followed by five successive heat pain trials with the MEDOC TSA II unit, then returned a week later to undergo nVNS followed again by five heat pain trials. Related-samples statistical analyses were performed using Wilcoxon signed ranks test (WSRT) with the statistical program SPSS. The Institutional Review Board at the University of California, San Diego Health Systems approved the protocol. Informed consent was obtained for all study procedures. Results VNRS: nVNS compared to ShS stimulation demonstrated a significant decrease in 1) VNRS percent change of heat pain stimulus trial #1 compared to heat pain stimulus trial #5 (p=0.042), and 2) in reported percent change of VNRS within heat pain stimulus #5 (p=0.038) (Figure 1). Similarly, nVNS trended to show a significant percent decrease in VNRS for heat pain trials 1 and 3 (Figure 1). GSR: nVNS stimulation demonstrated a significant percent decrease in pain-mediated GSR means after nVNS when compared to ShS for trial 1 (p=0.028) (Figure 2). Peak-to peak levels following heat pain after nVNS compared to ShS trended to decrease for heat pain trial 3 (p=0.063) (Figure 3). HRV: For all subjects, nVNS stimulation trended to increase high frequency and decrease low frequency HRV following heat pain compared to SHS. Conclusions These pilot data show that nVNS decreased reported heat pain, blunted the autonomic response in response to heat, and decreased the subjective experience of pain.
Wednesday, April 6 - Sunday, April 10Abstract: Waste Not, Want Not: Exploring the Archaeological Significance of Copper Production Waste Mounds at Khirbat al-Jariya, Faynan, Jordan Brady Liss and Thomas E. Levy Recent excavations by the Edom Lowlands Regional Archaeology Project at Khirbat al-Jariya (KAJ), an Iron Age (ca. 1200-586 BCE) copper smelting center in Jordan's Faynan region, aimed to explore the site's rich metallurgical history. KAJ is characterized by architectural features and large slag (smelting waste byproduct) mounds visible on the surface, attesting to its significance as a copper production site. These renewed excavations investigated the abundant metallurgical remains by probing into one such slag mound. This small probe, a 1x1 meter sample excavated to bedrock, provided a complete picture of smelting activity over the site's history. Furthermore, excavators collected slag samples from stratigraphically controlled contexts within the probe and other slag mounds. These samples were subsequently subjected to elemental analysis by X-Ray Fluorescence (XRF) to supplement the archaeological record. By combining XRF results with the chronological framework provided by archaeological excavation, it's possible to diachronically compare elemental concentrations within the slag samples. Together, the excavated material and analytical results (here also building on findings from the 2006 excavations) provide the necessary foundations to reconstruct the metallurgical narrative of KAJ. Thus, this paper presents the results of recent field and laboratory work along with their implications concerning copper production at KAJ.
Wednesday, April 13 - Saturday, January 16Abstract: The social brain in human evolution: neuron density in the prefrontal cortex in Williams Syndrome C. HORTON1, C.BROWN2, U. BELLUGI3, K. SEMENDEFERI1 1Univ. of California, San Diego, La Jolla, CA; 2Univ. of California, Santa Barbara, Santa Barbara, CA; 3Salk Institute, La Jolla, CA. The prefrontal cortex (PFC) is linked to many higher-order functions involved in human cognition and social behavior, and has likely undergone recent, rapid and functionally significant change in human brain evolution. It has been hypothesized that recent neural specializations and increased connective complexity in the human brain, which allow for the cognitive and social behaviors characterized as uniquely human, may have also resulted in an increased vulnerability to neurodevelopmental disorders. Comparative neuroanatomical studies with neural pathologies that include a social component may therefore illuminate characteristics of neural architecture that are critical for normative function of the social brain, and may offer new insight into the evolutionary trajectory of the social brain in humans. Here we examined neuron density in the supra- and infragranular layers of the PFC (BA 10 and 11) and three other areas, including sensory, motor and visual cortex (BA 3, 4, and 18) in six typically developing individuals (TD) and six individuals with Williams Syndrome (WS), a neurodevelopmental disorder with a known genetic deletion and a distinct socio-behavioral phenotype. We found that neuron density was decreased in WS relative to TD in the PFC areas only, with the infragranular layers, which have connections to subcortical structures of the social brain, such as the amygdala, demonstrating the largest decrease in density. These results suggest that cytoarchitectonic changes in neuron density in the PFC underlie the socio-behavioral abnormalities of WS, and may be indicative of neural specialization and increased connective complexity of the social brain in human evolution.
Clearwater Beach, Florida
Friday, January 29 - Wednesday, February 3Abstract: Background and Purpose: Research on the built environment and physical activity typically has focused on macroscale features such as residential density or street connectivity. However, growing evidence suggests that microscale pedestrian environment features, such as sidewalk quality, crosswalks, and neighborhood aesthetics, may also affect residents' physical activity. To date, only a few studies have examined whether microscale environments vary based on neighborhood income or racial ethnic composition. The studies that have examined potential disparities in microscale environments have used relatively undeveloped measures, or focus on a single city without examining how microscale environments vary across or within cities (i.e., residential versus mixed-use areas). Given that national and international authorities have identified the elimination of health disparities as a priority, examining disparities in microscale pedestrian features is a first step toward addressing potential disparities in physical activity environments. Objectives: The objective of the present study was to conduct an in-depth examination of microscale pedestrian environments in three US regions with markedly different SES levels, racial/ethnic composition, and walkability characteristics, and determine whether the quality of these environments are associated with neighborhood income and racial/ethnic composition. Methods: The present analysis used microscale environment data collected in three observational studies that explored the relationship between the built environment and physical activity: the Neighborhood Impact on Kids (NIK) Project, the Teen Environment and Neighborhood (TEAN) Study, and the Senior Neighborhood Quality of Life Study. Neighborhoods, defined as Census block groups, were selected to maximize variability in median income and macroscale walkability factors (e.g., density, street connectivity, and land use mix). Using the validated Microscale Audit of Pedestrian Streetscapes (MAPS), pedestrian environment features were assessed by trained observers along Â¼-mile routes (N = 2117) in neighborhoods in three US metropolitan regions (San Diego, Seattle, and Baltimore), during 2009 to 2010. The route served as the unit of analysis in the present study. Mixed-model linear regression analyses explored main and interaction effects of income and race/ethnicity separately by region. Results: Across all three regions, low-income neighborhoods and neighborhoods with a high proportion of racial/ethnic minorities had worse aesthetics and more negative social elements (e.g., graffiti, broken windows, litter) than neighborhoods with higher median income or fewer racial/ethnic minorities (p<.05). However, there was also many instances of worse pedestrian features in areas with higher incomes and fewer racial/ethnic minorities, specifically relating to sidewalks, crosswalks, and intersections (p<.05). Disparities in microscale pedestrian features occurred more frequently along routes that were residential-only as compared to mixed-use, but variation existed between regions. San Diego and Seattle regions had more disparities on residential routes as compared to mixed-use routes, whereas the Baltimore region had an equal number of disparities in residential and mixed-use routes. Conclusions: The present study shows a greater level of complexity and variability in disparities in streetscape environments than previously documented. The variability between cities brings into question the ability to generalize findings of single-city studies across different U.S. regions. Disparities in microscale pedestrian features that disfavored low-income or high racial/ethnic minority neighborhoods were observed in each region, but the unfavorable features differed by region and by residential/retail character of routes within each region. Implications for Practice and Policy: An advantage to understanding the role of microscale features is that their improvement may be a more feasible and affordable approach to creating activity-friendly environments as compared to changing macroscale urban features such as the layout of roads. Given the variation in microscale environments between and within cities, local streetscape audits are recommended to identify disparities and efficiently allocate resources for improving the pedestrian environment. Using information from streetscape audits, local policy makers, urban planners, and community groups can make targeted changes to increase physical activity opportunities for all residents, regardless of race, ethnicity, or income. Support/Funding Source: This study was supported by National Institutes of Health grants RO1 ES014240, RO1 HL083454, and RO1 HL077141.
Wednesday, April 13 - Saturday, April 16Abstract: Comparison of maternal investment in two troops of wild olive baboons (P. anubis) at ecologically different sites in the Laikipia Plateau, Kenya. CORINNA A. MOST, SHIRLEY C. STRUM. This project used long-term behavioral data to investigate the effects of ecological changes on maternal investment in a wild primate. Two troops of olive baboons (P. anubis) on the Laikipia Plateau, Kenya, were followed over the course of 12 months and focal data collected on 40 mother-infant dyads. The troops had distinct ranges more than 10Km apart differing in the density of a calorie-rich invasive cactus species (Opuntia stricta), which has spread since 2000 in one area and since 2005 in the other. The cactus' fruits now comprise an important part of the animals' diet, and females in the troop with longer exposure and higher density of Opuntia plants have earlier age at first birth and shorter inter-birth intervals, with values similar to those of captive or crop-raiding baboons. We used behavioral data to compare the two troops, and to investigate how these ecological changes have influenced mother-infant relationships. In particular, we focused on whether females in the Opuntia-rich area had reduced the amount of maternal investment in their infants because of their faster-paced reproductive schedule. As expected, females in the enhanced food environment spent significantly less time carrying their infants. However, infants in the two troops did not spend significantly different time nursing. This suggests that some aspects of maternal investment might be more flexible and responsive to rapid ecological changes than others. It also highlights the importance of embedding behavioral data within the broader ecological context and the value of long-term studies of wild primates.
Wednesday, March 30 - Sunday, April 3Abstract: Public reason projects attempt to justify state coercion from each citizen's perspective. This approach to political philosophy is often justified by a commitment to state neutrality about the good: the state must not appeal to controversial conceptions of the good in justifying its coercive actions. Political perfectionists reject this neutrality requirement and attempt to justify state coercion in terms of what is in fact good, rather than in terms of what is good from each citizen's perspective. In this paper, I appeal to uncontroversial claims about the epistemology of disagreement in order to show how even philosophers who reject state neutrality should still go in for public reason.
University of Pennsylvania, Philadelphia, Pennsylvania
Friday, February 26 - Saturday, February 27Abstract: Maya Ruins in the Modern Imagination: Mayan Revival Architecture and the Failure of Technology in Frank Lloyd Wright's Los Angeles Projects In the 1910s and 20s, an exceptional episode occurred in Frank Lloyd Wright's architectural practice. He turned away from the tenets of architectural modernism ”which privileged sleek, minimal surfaces and an absence of ornamentation ”and toward an aesthetic clearly poached from a strange admixture of Maya, Aztec, and Toltec architectural styles. Though Wright's Hollyhock House (1918-21) and the Millard, Freeman, Storer, and Ennis houses (1923-24) quickly became known as key examples of Mayan Revivalism, Wright denied any architectural affinities between his designs and their ancient counterparts. However, during the 19th century, the use of photographic technologies in U.S. archaeological expeditions to Mexico burgeoned, and the first life-size plaster replicas of Maya ruins were displayed alongside photographs of the ruins at the 1893 Chicago World's Fair, which Wright attended. Just a few years prior to beginning his Los Angeles projects, Wright also visited the 1915 Panama-California International Exposition in San Diego, which included a number of buildings mimicking Mesoamerican architecture. Yet Wright feigned ignorance of his theft of ancient aesthetics. Rather, he claimed his designs both fulfilled the need for a new regional vernacular architecture and communicated something of the universal spirit of modernism so popular at the time. In lieu of using the carefully hewn stone and stucco that ancient Mesoamericans had used to build their monumental religious, political, and cultural centers, Wright used what was a brand new technology at the time ”the knit-block construction method ”in which uniform blocks of cast concrete were knit together with steel supports. Today, though the materials of Mesoamerican ruins such as Palenque have endured, in some cases, for millennia, Wright's buildings have fallen into ruin. What were thought to be hallmarks of technological innovation during the early decades of the 20th century are now weathered by the Los Angeles pollution and crumbling from poor construction, inappropriate materials, and shifting foundations. Nearly contemporaneous with Wright's California designs, however, the Mayan aesthetic was being successfully put to use in U.S. urban architecture in the form of the stepped pyramidal shape of the modern skyscraper (the Fisher Building in Detroit and 450 Sutter Street in San Francisco are key examples). This paper seeks to explore the lineage of technological innovations (and failures) that popularized Mesoamerican ruins to a U.S. audience, focusing on Wright's forays in Mayan Revival architecture. This lineage ranges from the first camera lucida drawings by architect Frederick Catherwood to the casting methods and photographic technologies used by 19th century archaeologists. Taking a closer look at the surprising transmission of pre-Columbian architecture in the U.S. cultural landscape necessitates a historiographic approach that relies on the fields of archaeology, the political history of U.S.-Mexico relations, and both ancient and modern architectural history. By looking principally at the example of Mayan Revivalism, I argue that the role of Mesoamerican antiquity in the national imagination of American architectural modernism is both hidden and problematic. The anachronistic connection between the ancient and the modern in this case is inextricably tied to issues of U.S. national identity and reflects various aspects of the complex political and cultural relationship between the United States and Mexico since Mexican Independence.
Tuesday, April 12 - Wednesday, April 13Abstract: For three years I have been honing my skills and technique as an actor. I have worked on Shakespeare and Eugene O'Neill as well as new plays by young UCSD MFA playwrights. I have witnessed my body become more fine-tuned, my voice deepen and range increase. I am leaving school full of a wonderful education and eager to take my talents into the professional world. I hope to use my art as an agent of change. It is at this UCSD Showcase that I will make my theatrical entrance into the professional world. From there, my deepest wish is that I will meet someone from showcase that understands what I offer and this partnership will lead to the next level in my professional career.
Fernando Soto Alvarez
San Luis PotosÃ, Mexico
Friday, February 26 - Friday, February 26Abstract: Traditional technology cannot be simply scaled down due to the dominating viscosity forces (over inertia forces) at lower scales that affect both the movement and directionality. Accordingly, small scale machinery tools need to be powered and actuated by fundamentally different approaches than macroscopic devices. New nanomachine strategies have been developed recently in this direction. Such tiny machines hold great promise for diverse future applications. There are still challenges in translating this remarkable into in-vivo or industrial procedures, for this is necessary to develop novel propulsion mechanisms that could be powered wirelessly of by their chemical environment. Recent advances in the field of micromotors have led to their growing use for accelerating chemical reaction rates compared to static particles, owing to efficient fluid mixing that arises from the self-propulsion of micromotors. This mixing has been shown to be extremely effective in accelerating target-receptor interactions, bio-detection, and detoxification and decontamination processes. The dream of these tiny machines swimming inside the human body is still far away, but the opportunities it offers could revolutionize our world.
Four Points Sheraton / Holiday Inn Express Ventura, CA
Sunday, March 6 - Friday, March 11Abstract: The search for compounds produced by marine organism has already resulted in seven FDA approved drugs for the treatment of various diseases, like cancer and virus infections. With this in mind and reflecting upon how much biological and, therefore, chemical diversity is still unknown we can appreciate the potential of ongoing studies for developing forthcoming chemotherapies. Electrophilic natural products are small molecules consistently found in Nature that contain reactive functional groups. Due to their reactivity these molecules can interact with nucleophilic biomolecules (like proteins and DNA) to cause a biological response, which could be an advantageous trait for organisms that produce them. In the biomedical realm, it was recently realized that 33% of the enzymes targeted by FDA approved drugs where inhibited by a covalent mechanism of action, which is the way in which electrophilic natural products act. Both of these virtues highlight the usefulness of this class of molecules. In response, we devised a new synthetic methodology termed reactivity-guided isolation applied to the discovery of electrophilic natural products from complex mixtures based on the molecules' mechanism of action. Utilizing specially designed probes that mimic nucleophilic amino acid residues and that contain MS, UV and crystalline moieties, our approach has shown to chemoselectively react with known electrophilic natural products in crude extracts, guide their isolation and simplify their structural elucidation. Now, we hypothesize that by incorporating resin-immobilized probes the method could streamline the isolation of electrophilic natural products to a single solid-phase reaction step and even increase the detection limit for metabolites found in low concentrations. Herein, I describe the synthesis of the immobilized probes and its validation for use in the discovery of unknown electrophilic natural products from marine Actinobacteria.
San Jose, Costa Rica
Thursday, March 31 - Sunday, April 3Abstract: As children navigate the social world they must decide how to balance their own self-interests with the interests of others. The present study examines how children approach such decisions within the context of sharing resources. In the current study, 100 participants, aged 5 to 9 years, completed a sticker-sharing task with a potential recipient in the presence or absence of an observer. Whether the potential recipient was an in-group or out-group member was manipulated using a minimal group paradigm. Next, children evaluated scenarios depicting in-group and out-group giving to see if their beliefs regarding sharing mirrored their own giving behavior. Additionally, we explored children's beliefs regarding sharing with in-group and out-group members, and tested whether this mirrored their own sharing behavior. We found that (a) children donated more stickers in the presence of an observer and (b) gave more stickers to in-group than out-group members though this did not differ by observer condition. We also found that children evaluated giving to out-group members as less nice than giving to in-group members. Children's beliefs regarding how others should share resources did not parallel their own sharing behaviors. These findings suggest that children make sharing decisions in the context of reputation concerns and perceived social obligations to in-group members, although the two motives do not interact. The present study examines how children decide with whom to share resources. In the current study, 160 participants, aged 5 to 9 years, completed a sticker-sharing task with a potential recipient in the presence or absence of an observer. Whether the potential recipient was an in-group or out-group member was manipulated using a minimal group paradigm. Next, we explored children's beliefs regarding sharing with in-group and out-group members, and tested whether this mirrored their own sharing behavior. We found that (a) children donated more stickers in the presence of an observer and (b) gave more stickers to in-group than out-group members though this did not differ by observer condition. We also found that children evaluated giving to out-group members as less nice than giving to in-group members. Children's beliefs regarding how others should share resources did not parallel their own sharing behaviors. These findings suggest that children make sharing decisions in the context of reputation concerns and perceived social obligations to in-group members, although the two motives do not interact.
Buffalo, New York
Saturday, April 9 - Sunday, April 10Abstract: Title: Border Poetics, Mourning and the Politics of the Disappeared Jeanine Webb I propose a paper that would interrogate the notion of a "post-crisis poetics" and replace this focus with a focus on the poetics of permanent crisis as manufactured by capital, market reproduction and state violence. This paper would examine poetic reactions to this state of permanent crisis in relation to trauma, mourning and social movements in contemporary poetics. In particular, my paper would focus on Tijuana-San Diego poetics and social movements in the context of the disappearance of 43 students at Ayotzinapa and poetic responses of Mexican and U.S. border poets to this traumatic crisis of disappearance and to the surrounding associated insurrectionary direct action. The paper would concentrate its inquiries on David L. Eng and David Kazanjian's anthology Loss: The Politics of Mourning, the border area poetry and politics group Colectivo Intransgiente and state and cartel violence against poets in Mexico and the San Diego-Tijuana border region of the last several years. The paper would consider some of the current poetics of social and insurrectionary movements against state violence, in relation to the politics of mourning as pathways to keep alive as well as mourn the memory of the disappeared.
Pacific Grove, CA; Asilomar Conference Grounds
Friday, February 19 - Sunday, February 21Abstract: What role do organizational interests play in the market-orientedness of American colleges and universities? Sociologists of higher education have described and analyzed the market-orientation of postsecondary institutions and generally concluded that, due to government policies and the rise of neo-liberal ideology, colleges and universities have made a general turn to free-market, laissez-faire programs. The case of government sanctioned tuition trust programs (i.e., prepaid tuition programs, or tax-exempt investment accounts allowing families to pre-pay college tuition) contradicts this general trend because higher education leaders in various states have been opposed. Between 1985 and 2014 most states considered the enactment of tuition trusts and about one-third approved them. As tuition has continued its precipitous rise citizens have demanded, and politicians have responded with, policies that mitigate high tuition. But while much of the government's response has been focused on financial aid for low-income students and loans, tuition trusts provide a savings and investment strategy primarily enjoyed by the affluent. My study of the legislative adoption of tuition trusts shows that market-oriented policies do not always support organizational autonomy and revenue generation. When presented with a market policy which threatens their organizational interests, higher education leaders work to oppose it. I found that in the three states included in my analysis ”California, New York, and Texas ”when higher education leaders pushed against such policies the legislation failed; when they did not perceive tuition trusts as a threat and were neutral on the subject the legislation succeeded.
Los Angeles, California
Thursday, April 7 - Saturday, April 9Abstract: The neurological motor exam provides important information about a patient's clinical status. However, there are several limitations of the exam, which include assessment subjectivity and the frequency with which it can be performed. We propose automating motor score assessment by passively measuring activity with accelerometers. In this work, we train a linear model against hourly motor scores and use past scores and accelerometer features as model inputs. In several cases, the model achieves significant correlation (P<2.68E-5, Bonferroni corrected) with actual scores, indicating that it may be feasible to estimate motor scores with accelerometers.
Wednesday, March 16 - Saturday, March 19Abstract: How can we identify policy preferences of elites in closed autocratic regimes? In the absence of available information on the inner workings of the North Korean regime, outside observers often have to rely on subjective expert opinion or survey responses from North Korean refugees. Instead, we turn to the recent methodological advances in text analysis and generate a new dataset of more than 150,000 news articles from the Korean Central News Agency. Using a structural topic model, we uncover temporal trends in each estimated topics, as well as the associations between some notable estimated topics and events data incorporating political and military provocations. Given the importance of propaganda in closed autocratic regimes, we assume the content of media reflects policy preferences of elites close to the North Korean leadership. By generating a composite score of key identifiers such as provocation intent or anti-American sentiment, we provide a novel approach to shed light on foreign policy preferences of North Korean elites. We test the relevance of our measure by using it to predict known past political and military provocations. Moreover, we test an additional hypothesis that the heightened rhetoric of threat is driven mostly by levels of stability within the elite core
Cold Spring Harbor, NY
Wednesday, April 6 - Saturday, April 9Abstract: John Scott, Sonal Thakar, Mao Ye, Ting Yu, and Yimin Zou Neurobiology Section, Division of Biological Sciences, University of California, San Diego Processes of assembly, maintenance, pruning, and plasticity tightly regulate synapses, the specialized connections between neurons, and allow animals to respond to a wide range of environmental stimuli. Neurons form tens of thousands of connections with partners to determine circuit function in the brain. A growing number of synaptic molecules have been associated with neurological diseases including Autism Spectrum Disorders. Lethal giant larvae homolog 1 (Lgl1) has been previously shown to play a significant role in early phases of neuronal development. We propose that in addition to its importance in early development, Lgl1 also plays an important role in synapse assembly, possibly in conjunction with either fmr1 or the Par complex. The Lgl1 gene is located within the Smith-Magenis Syndrome (SMS) deletion region and patients with SMS are frequently (>80%) diagnosed with Autism or other behavioral disorders, though the behavioral phenotypes observed in the syndrome have yet to be specifically assigned to any of the deleted genes. We show that apical-basal polarity components Lgl1 and Atypical Protein Kinase C are asymmetrically localized between synaptic compartments. We demonstrate that deletion of Lgl1 results in 1) increased excitatory synapse number; 2) impaired synaptic plasticity; 3) altered presentation of postsynaptic receptors; and 4) behavioral phenotypes resulting from synaptic changes. Following conditional deletion of Lgl1 at the beginning of synaptogenesis, excitatory synapse number in the hippocampus increases by approximately 28% as shown by electron microscopy and recording of mEPSC events, while inhibitory synapses are not affected. This increase persists into adulthood. Slices from conditionally deleted animals fail to show long-term potentiation in response to Theta Burst Stimulation (TBS). In addition, the ratio of AMPA to NMDA receptors at the synapse is reduced. When Lgl1 deletion is instead induced in adult animals, a similar increase in excitatory synapse number is observed. Using genetic and viral tools to delete Lgl1 either at the onset of synaptogenesis or in adulthood, we demonstrate behavioral phenotypes related to changes in synapse number and synaptic plasticity. Mice with conditional deletion of Lgl1 show increased locomotor activity in the Open Field test. In the 3-chambered Social Interaction Test, mice with conditional deletion of Lgl1 spend less time with the novel target mouse compared with littermate controls. Mice with conditional Lgl1 deletion also fail to distinguish novel from familiar objects in the Novel Object Recognition task. Some behavioral phenotypes are recapitulated in heterozygote mice from the Lgl1 conventional knockout line, indicating a role for Lgl1 in some symptoms of SMS.
Tuesday, April 5 - Friday, April 8Abstract: The San Diego-Tijuana Earthquake Scenario project aims to examine the impact that a probable major earthquake will have on the San Diego-Tijuana metropolitan region, and define methods for mitigation. It is a bi-national effort between two cities that share the same geologic and tectonic environment and have common infrastructure. The project is divided into three working groups. The first group, which has already completed its charge, focused on specifically characterizing the probably earthquake hazard. Based on a previous scenario for the same area drafted in 1990, members of the Hazards working group selected a M6.9 earthquake rupturing on the Rose Canyon fault with directivity towards Tijuana,. Based on this scenario event, a shakemap with various peak spectral accelerations was also developed, as well as a preliminary estimate for the various types of losses along with some secondary hazards derived from the earthquake shaking (e.g tsunamis, surface rupture, liquefaction etc.). The second working group, which is currently in progress, is focused on assessing the building and infrastructure inventory for downtown San Diego and Tijuana, which will be used by , a multi-hazard loss estimation methodology developed by FEMA in the 1990's (HAZUS). HAZUS combines geologic data and the latest building inventory to estimate a region's earthquake losses.. Many UCSD graduate students are currently working in close collaboration with professors and local industry professionals to identify the building stock for various types of critical facilities by evaluating building inventory data, such as geospatial information, building type and year, and other critical design parameters. These data are being collected from different existing databases, and will be imported into the HAZUS software. The building types being investigated in the first phase consist of important structures or building types that may significantly impact the resiliency of our cities, such as unreinforced masonry structures (URMs), schools, hospitals and other emergency response facilities, and critical infrastructure. Each building will be modeled individually along with some selected ones from the general building stock. The third working group is focused on the socio-economic impact of this scenario earthquake on the San Diego-Tijuana region. Based on the results of the most up to date Hazus run, the members of this working group will develop planning recommendations to minimize impact of the design event on the community and improve the resiliency of our cities. The final outcome of this project will be a detailed report aimed at improving government and community awareness of the seismic risk in the San Diego-Tijuana region,thus influencing the development of seismic retrofit measures, mitigation policies and earthquake preparedness planning. This poster will describe the overall San Diego-Tijuana Earthquake Scenario Project and will focus on the methodology used by working group 2 to inventory the current building stock in the two cities. Results from the most recent Hazus runs will be presented as well as recommendations for future work in this effort.
Downtown San Diego
Sunday, March 13 - Thursday, March 17Abstract: Microbial fatty acid biosynthetic enzymes are important targets for antibiotic development, chemical manufacturing and biofuel production. In Escherichia coli, the acyl carrier protein (AcpP) plays a central role by sequestering and shuttling the growing acyl chain between fatty acid biosynthetic enzymes. FabA, a hydroxylacyl-AcpP dehydratase, is an important enzyme in controlling fatty acid chain length and unsaturated fatty acid amounts. Understanding the 10-carbon chain length preference of FabA, and the preference of other fatty acid biosynthetic enzymes, is crucial for understanding and ultimately manipulating this metabolic pathway. In this study, four mechanistic crosslinking probes mimicking varying acyl chain lengths were synthesized to probe for chain length specificity of fourteen FabA mutants. The three FabA regions mutated were the AcpP interacting positive patch, substrate-binding pocket and gating residues. These studies shed light on the importance of the positive patch for AcpP-partner protein interactions, and help elucidate the chain length preference of FabA.
Wednesday, March 30 - Saturday, April 2Abstract: Veterans with combat exposure (CE) experience physical health outcomes associated with disability and poor quality of life. Understanding the CE-physical health relationship, specifically pain intensity and pain interference, may inform etiological models and interventions. This study sought to examine the CE-pain relationship and associated moderators and mediators. 2,381 Veterans registering for healthcare at the VA San Diego Healthcare System (VASDHS) completed paper or electronic self-report measures, including a pain rating scale and the PHQ-15 to assess pain intensity and interference, respectively. Analyses determined differences in pain intensity and interference by CE group and examined gender as a moderator. Mediated moderation models analyzed factors through which gender moderated the CE-pain relationships. Controlling for age, Veterans with CE had higher pain intensity (p < .001, R2 = .02) and pain interference (p < .001, R2 = .05), and gender significantly moderated these associations (p's < .05). Men with CE had higher pain intensity and interference compared to men without CE, whereas women with and without CE had comparable levels of pain. Mediated moderation analyses showed PTSD symptoms mediated the moderation of the CE-pain relationships by gender. Findings showed that CE is associated with poor pain outcomes, with effects differing by gender, and that these gender differences may occur through PTSD symptoms. Elucidating the mechanisms whereby CE impacts physical health is essential. Future studies should examine gender differences and mediators in the CE-pain relationship using longitudinal designs to inform etiological models and development of targeted health interventions.
Wednesday, February 3 - Saturday, February 6Abstract: 2 abstracts being presented as posters: Title: Verbal Learning and Memory Profiles in HIV-associated Neurocognitive Disorders: A Comparison with Huntington's Disease and Temporal Lobe Epilepsy Authors: Katie L. Doyle, Steven Paul Woods, Carrie McDonald, Kelly Leyden, Heather Holden, Erin E. Morgan, Paul E. Gilbert, & The HNRP Group. Objective: Up to 65% of individuals with HIV-associated neurocognitive disorders (HAND) evidence episodic memory impairment that is broadly characterized as a mixed encoding/retrieval profile consistent with a classic subcortical presentation. The current study evaluated this hypothesis by comparing the extent to which the pattern of HIV-associated episodic memory deficits correspond with those of populations with traditional subcortical (i.e., Huntington's Disease) versus cortical (i.e., Temporal Lobe Epilepsy) profiles. Participants and Methods: Seventy-seven individuals with HAND, 47 individuals with Huntington's Disease (HD), 21 individuals with Temporal Lobe Epilepsy (TLE), and 45 healthy participants who were demographically matched on age, education, and ethnicity were administered the California Verbal Learning Test - 2nd Edition (CVLT-II). CVLT-II profiles were classified as reflecting a primary encoding deficit (e.g., poor free recall and recognition, intrusion errors), retrieval deficit (e.g., impaired acquisition and free recall but intact recognition), or normal (i.e., intact acquisition, recall and recognition) using the Massman et al. (1992) discriminant function algorithm. Results: In a logistic regression model adjusting for sex, clinical group membership was a significant predictor of verbal memory profile type (p<.01). The HD group evidenced the lowest proportion of individuals with normal profiles (13%), with HAND (38%) and TLE (38%) groups falling intermediate to the healthy group (78%). Among participants with a CVLT-II deficit, the HAND group showed the highest rates of retrieval versus encoding profiles (71% vs. 29%), followed by HD (59% vs. 41%), TLE (46% vs. 54%), and healthy (50% vs. 50%) groups. Conclusions: Findings suggest that HIV-associated episodic verbal memory impairments are most consistent with a traditional subcortical, retrieval deficit profile, which is consistent with the primary frontostriatal neuropathogenesis of HIV disease. Nevertheless, there is significant profile heterogeneity in HAND, as well as in HD and TLE, which may reflect neuropathological variability, measurement error, and/or the influence of secondary variables (e.g., cognitive and brain reserve) in these populations. _____________________________________________ Title: The Effects of HIV-associated Neurocognitive Disorders Across An Integrated Functional Model of Health Literacy Authors: Katie L. Doyle, Steven Paul Woods, Erin E. Morgan, Marizela V. Cameron, & The HNRP Group Objective: HIV-associated neurocognitive disorders are associated with deficits in health literacy, a multifactorial construct encompassing abilities that are essential for making optimal health decisions. However, the impact of HAND across different functional levels of health literacy is not known. The present study adopted Sorensen's (2012) integrative health literacy theory to examine the potential differential effects of HAND across core health literacy domains. Participants and Methods: Thirty-seven HIV+ individuals with HAND (HAND+) and 44 HIV+ individuals without HAND (HAND-) who were matched on demographic, psychiatric, and HIV disease characteristics completed standardized neuromedical, psychiatric, and neurocognitive research evaluations, alongside a comprehensive health literacy battery that assessed Sorensen's (2012) core domains of motivation, knowledge, competence, understanding, and appraisal/application. Results: A multivariate ANOVA controlling for education revealed a significant interaction between HAND and health literacy domains (p<.01), such that the HAND+ group evidenced poorer scores than the HAND- group within domains of knowledge, competence, understanding, and appraisal/application (ps<.05, Cohen's d range=.64-1.23), but not motivation (p>.05, Cohen's d=.45). Within the HAND+ group, deficits in these four domains were associated with worse performance within neurocognitive domains of learning and executive function (ps<.01) Conclusions: Findings suggest that individuals with HAND evidence lower health literacy across some, but not all core domains, including both lower- (e.g., knowledge) and higher-order (e.g., appraisal/application) , all of which depend on learning and executive functions (e.g., cognitive flexibility) Evaluation of established learning (e.g., spaced retrieval, interleaving) and executive function (e.g., goal-management training) strategies to enhance aspects of health literacy in HIV may be warranted.
San Diego, CA
Sunday, March 13 - Thursday, March 17Abstract: RNA exists in cells as ribonucleoprotein complexes (RNPs), containing RNA and associated RNA binding proteins (RBPs). RBPs play a critical role in determining the cellular function of RNA, and therefore methods to identify RNA-protein interactions are of tremendous interest. Here, we demonstrate the site-specific labeling of RNA transcripts using the RNA-TAG (transglycosylation at guanosine) methodology. This technology takes advantage of a bacterial tRNA transglycosylase (TGT) capable of incorporating nucleobase derivatives bearing functional probes into an encodable RNA stem loop recognition motif. Using this methodology, we have successfully labeled mRNA transcripts with a wide variety of probes including biotin, BODIPY, and Cy7 in a single enzymatic step. Endogenously transcribed and processed RNAs containing the RNA-TAG recognition hairpin in their 3' UTR can be selectively visualized in cell imaging studies. Furthermore, we have demonstrated that an RNA of interest can be selectively biotinylated and affinity purified from a complex mixture of RNAs and cell lysate. Through the development of RNA-TAG, we aim to create a robust, convenient platform for the elucidation of RNA function via cellular localization studies and affinity purification of RNA-protein complexes.
Tuesday, March 1 - Friday, March 4Abstract: Title: Examining The Effect of The Accumulation of Physical Activity on Blood Pressure in a Physical Activity Intervention for Community Dwelling Older Adults. Authors: Kelsie M. Full, MPH, Katie Crist, MPH, Suneeta Godoble, Jacqueline Kerr, PhD Background: High blood pressure is one of the most common health conditions experienced by US older adults. Hypertension leads to heart disease, CVD incidence, stroke, and death. In older adults, community based physical activity (PA) interventions have been shown to significantly decrease systolic and diastolic blood pressure. The American Heart Association Physical Activity Guidelines recommend that adults accumulate at least 150 minutes of moderate-vigorous intensity physical activity (MVPA) per week in order to obtain substantial health benefits. It is not clear whether accumulation of total minutes of physical activity is more important for significant changes in cardiovascular health, including reductions in blood pressure levels, or whether the intensity of the physical activity is important. New physical activity assessment techniques allow us to assess daily minutes of intensity outside of the clinic environment. Study Objectives: The objective of this study was to assess the effects of total accumulation of PA, independent of time spent in MVPA, on changes in blood pressure in older adults participating in a 6-month physical activity intervention. Methods: Study data are from a multilevel physical activity intervention (MIPARC) for older adults. Residents over the age of 65 years (N=307, mean age 84) were recruited from 11 retirement communities in San Diego. Study evaluation included collection of blood pressure measures and 6 day hip-worn accelerometry data. Change in blood pressure (dependent variable) and PA (intensity and total) from baseline to 6 months and 6 months to 12 months were examined. To account for within person and within group clustering, hierarchical longitudinal mixed effect models were used. Results: Increases in total PA counts was related to significant decreases in systolic blood pressure over the 12-month intervention period, after adjusting for minutes of time spent in MVPA (p<.005). Conclusions: Evidence is mixed on the intensity of PA needed for older adults to experience significant health benefits, including reducing blood pressure. The results of this study suggest that for older adults, the total accumulation of PA at any intensity, is more important than PA at moderate to vigorous intensities. These findings have important implications for the design of PA interventions and PA prescriptions for older adults. More research is needed in older adult populations to examine if MVPA is beneficial to older adults, or if the relationship varies by an individual's cardiovascular health.
Baton Rouge, LA
Friday, February 19 - Saturday, February 20Abstract: Corals experience hyperoxia during the day due to Symbiodinium photosynthesis and hypoxia at night due to respiration by the coral holobiont. Previous studies have revealed corals undergo daily oscillations in the expression of putative metabolic genes. However, the anaerobic energy production pathways in corals are unknown. To study the link between nighttime hypoxia in coral tissues and cellular energy production, the branching scleractinian species Acropora yongei was studied in a laboratory setting. Oxygen concentrations were measured in the diffusive boundary layer using microelectrodes, demonstrating daily hyperoxia and nightly hypoxia. Branches were sampled every 4 hours over a diurnal cycle to measure metabolic enzyme activity, metabolites, and protein expression by 2D gels. For the first time, it was shown that corals produce strombine, an end metabolite of anaerobic glycolysis. High amounts of strombine were present in coral tissues during the day as well as at night. Enzyme activity assays revealed that aerobic energy producing pathways were significantly less active during the night versus the day. Thus, the relative contribution of anaerobic glycolysis was greater at nighttime, corroborating the concept of nightly functional anaerobiosis in corals. However, protein expression of detectable glycolytic and TCA cycle enzymes did not exhibit diel patterns. Therefore, the transition from aerobic metabolism during the day to anaerobic metabolism at night appears to be controlled on the substrate level and by posttranslational modifications to metabolic enzymes.
Cold Spring Harbor, New York
Monday, April 18 - Friday, April 22Abstract: Genetic and Phenotypic Analysis of Cytoplasmic Proteostasis All organisms face the universal problem of maintaining its proteins in a fully functioning state. Eukaryotes remove damaged proteins by a process called protein quality control which degrades unwanted proteins via the proteasome. Quality control mechanisms are compartmentalized and little is known about the quality control mechanisms in the cytosol. Our lab has discovered a role for Ubr1 in the management of cellular proteostasis. We have shown that Ubr1 can selectively identify damaged proteins from normal ones and ubiquitinate them for destruction by the proteasome. The overall goal of this project is to unravel the unknown mechanism of Ubr1 in the maintenance of cellular proteostasis. Specifically, I will 1) use a genetic approach to identify candidates of the cytosolic quality control pathway. I will construct a library expressing the model misfolded cytosolic substrate CPY-GFP to identify candidates that stabilize this substrate. 2) I will discern the roles of each discovered factor by biochemical and proteomic analysis used in the lab to test genes for their role in quality control. Finally, 3) I will survey a number of known conditions for imposing cell stress to better understand the role of Ubr1 in the management of proteostasis . Taken together, these mechanisms will be important in understanding both basic and biomedical aspects of cellular proteostasis.
GWU at Washington DC
Thursday, April 7 - Friday, January 8Abstract: In this presentation, I explore how crip sociality is distributed between multiple subjects, objects, and their interactions in academic and social worlds. This talk is itself the subject of this presentation. By attending to the meaning(s) of co-production via a scripted performance, this talk will be read aloud and made available through CART translation to reflexively reflect on the material conditions that make the presentation possible. I seek to expand on co-production as a term by asking how the unruly nature of intersubjective encounters between readers can shape and determine the co-production of the social. Essentially, I ask the question: what does it mean to crip sociality? This therefore considers how an individual's access might be mediated, or how this process of mediation creates space for agency, through crip forms of resistance. The potential for shaping a notion of crip sociality is primarily explored here as a method that can be used to show how both the subject and object of this study can be understood simultaneously as tools of distribution. The performative scope of this presentation will attend to the undoing of crip sociality to consider the distribution of access as a potential site that generates a crip/queer art of failure.
Tuesday, March 1 - Friday, March 4Abstract: Title: Abdominal Lean Muscle Mass is associated with the Density, but not the Volume, of Coronary Arterial Calcium and Abdominal Aortic Calcium Authors: Maggie Crawford, Matthew Allison, Michael Criqui, Britta Larsen Introduction: Higher volume of coronary arterial calcium (CAC) and abdominal aortic calcium (AAC) are predictive of incident CVD, while higher density of CAC and AAC are associated with lower risk. The purpose of the present study was to determine the associations of abdominal lean muscle mass (ALMM) with CAC volume, CAC density, AAC volume, and AAC density. Hypothesis: We hypothesized that abdominal muscle mass would be negatively associated with CAC and AAC volume but positively associated with CAC and AAC density. Methods: The current study analyzed data from the Multi-Ethnic Study of Atherosclerosis (MESA) in those subjects who underwent abdominal computed tomography (CT) to assess for AAC, which was also analyzed for volumes of fat (visceral and subcutaneous) and ALMM (psoas, rectus abdominis, obliques, and paraspinus). CAC and AAC were scored separately, for density and for volume. Results: Analyses were restricted to subjects who had non-zero CAC or AAC volumes. The sample sizes for the CAC analyses and AAC analyses were 963 and 1283 subjects, respectively. For the CAC analyses, 39.4% were female and the mean age was 66.4 years. Mean SD CAC volume was 218.52 344.19 (range 2.34- 3244.77 mm3) ; Mean SD CAC density was 2.70 .72 (range 0.83- 4.0 Hu category units). Mean SD AAC volume was 1402.33 1888 (range 4.68- 15822.2 mm3); mean SD AAC density was 3.02 .63 (range 0.83- 4.0 Hu category units). In multivariable linear regression models that controlled for age, race, gender, CVD risk factors, visceral fat, and liver and kidney markers, both CAC and AAC density were found to be significantly associated with abdominal lean muscle mass. For every 100 cm2 increase of ALMM, CAC density decreased by .35 Hu category units (p < .05). For every 100 cm2 increase of ALMM, AAC density decreased by .26 Hu category units (p < .05). Conversely, CAC and AAC volume were not significantly associated with abdominal lean muscle mass in final models. Conclusion: Higher levels of ALMM were associated with lower CAC and AAC density, but not volume. Contrary to expectation, we found an inverse association of ALMM with CAC and AAC density, independent of relevant CVD risk factors.
Monday, March 28 - Friday, April 1Abstract: We studied the influence of uniaxial  strain (-1% to +1%) on the electron transport properties of two-dimensional electron gas (2DEG) at the n-type interface of the LaAlO3/SrTiO3(LAO/STO) heterostructure (HS)-based slab system from the perspective of polarization effects via first-principles density functional theory calculations. We first analyzed the unstrained system, and found that the induced polarization toward the vacuum in the LAO film leads to a small charge carrier density on the order of 10E13 [cm^-2] (less than the theoretical value of 3.3 x 10E14 [cm^-2] from the superlattice-model-based polar catastrophe mechanism), which is in excellent agreement with the experimental values for oxygen-annealed LAO/STO HS samples. Upon applying a  tensile strain on the STO substrate, we found a significant reduction of the induced polarization in the LAO film. This reduction weakens the driving force against charge transfer from LAO to STO, causing an increase in the interfacial charge carrier density. The uniaxial strain also leads to a decrease of the effective mass of interfacial mobile electrons, resulting in a higher electron mobility. These findings suggest that applying a uniaxial  tensile strain on the STO substrate can significantly enhance the interfacial conductivity of the LAO/STO HS system, which gives a comprehensive explanation for experimental observations. In contrast, compressively strained LAO/STO systems show stronger LAO film polarization than the unstrained system, which reduces the interfacial charge carrier density and increases the electron effective mass, thus suppressing the interfacial conductivity.
UT Austin Campus. Austin, Texas
Thursday, March 3 - Sunday, March 6Abstract: In this paper, I analyze El Salvador's abortion ban as a form of biopolitics that aims to discipline women's bodies in the face of ongoing anti-state resistance. Abortion in El Salvador has been completely illegal since 1998, even in cases of rape, incest, fetal deformity, or when a woman's life is endangered by the pregnancy. There are currently over 137 women serving abortion-related charges in El Salvador, and some will spend upwards of forty years in prison for aggravated murder. In 2014, the campaign Las 17 coalesced to reference seventeen particularly punitive cases; protestors and community organizers continue to use the term in demonstrations outside of Ilopango prison and the National Medical Institute. Las 17 is a political formation that calls attention to methods of state surveillance in El Salvador; many women for example are arrested in hospitals while still under anesthesia, and are thereafter enlisted in gendered labor in prison such as crocheting or making piÃ±atas. I intend to situate the criminalization of women's reproductive health in El Salvador as an expression of state sovereignty that extracts labor power from incarcerated women. Furthermore, I argue that the draconian ban on abortion illustrates how multiple institutions partner in producing state sovereignty over women's bodies, including patriarchal Catholicism, Salvadoran hospitals, political law and the Ilopango prison. I hope to unpack the relationships amongst these state and non-state actors, while also understanding them as formed in opposition to ongoing expressions of resistance against the ban on abortion
Tuesday, March 15 - Wednesday, March 16Abstract: Static Random Access Memories (SRAMs) occupy a large area of today's microprocessors, and are a prime source of leakage power in highly scaled technologies. Low leakage and high density Spin-Transfer Torque RAMs (STT-RAMs) are ideal candidates for a power-efficient memory. However, STT-RAM suffers from high write energy and latency, especially when writing ˜one' data. In this paper we propose a novel data-aware hybrid STT-RAM/SRAM cache architecture which stores data in the two partitions based on their bit counts. To exploit the new resultant data distribution in the SRAM partition, we employ an asymmetric low-power 5T-SRAM structure which has high reliability for majority ˜one' data. The proposed design significantly reduces the number of writes and hence dynamic energy in both STT-RAM and SRAM partitions. We employed a write cache policy and a small swap memory to control data migration between cache partitions. Our evaluation on UltraSPARC-III processor shows that utilizing STT-RAM/6T-SRAM and STT-RAM/5T-SRAM architectures for the L2 cache results in 42% and 53% energy efficiency, 9.3% and 9.1% performance improvement and 16.9% and 20.3% area efficiency respectively, with respect to SRAM-based cache running SPEC CPU 2006 benchmarks.
Monday, March 28 - Friday, April 1Abstract: We studied the defect formation energies, oxidation states of the dopants, and electronic structures of Bi-doped NaTaO3 using first-principles hybrid density functional theory calculations. Three possible structural models including Bi-doped NaTaO3 with Bi at Na site (Bi@Na), with Bi at Ta site (Bi@Ta), and with Bi at both Na and Ta sites [Bi@(Na,Ta)], are constructed. Our results show that the preferred doping sites of Bi are strongly related to the preparation condition of NaTaO3. It is energetically more favorable to form Bi@Na structure under Na-poor condition, to form Bi@Ta structure under Na-rich condition, and to form Bi@(Na,Ta) structure under mildly Na-rich condition. The Bi@Na doped model shows an n-type conducting character along with an expected blueshift of the optical absorption edge, in which the Bi atoms exist as Bi3+ (6s2 6p0 ). The Bi@Ta doped model has an empty gap states consisting of Bi 6s states in its band gap, which can lead to a visible-light absorption via the electron transition among the valence band, conduction band, and the gap states. The Bi dopant is present as Bi5+ ion in this model, consistent with the experimental result. In contrast, the Bi@(Na,Ta) doped model has an occupied gap states consisting of Bi 6s states in its band gap, and thus the visible-light absorption is also expected in this system due to the electron excitation from these occupied states to the conduction band, in which the Bi dopant exists as Bi3+ ions. Our first-principles electronic structure calculations revealed the relationship between the Bi doping sites and materials preparation conditions, and clarified the oxidation states of Bi dopants in the NaTaO3 as well as the origin of the different visible-light photocatalytic hydrogen evolution behavior in Bi@Ta and Bi@(Na, Ta) doped NaTaO3. This work can provide a useful reference for preparing Bi-doped NaTaO3 photocatalyst with desired doping sites.
Thursday, January 28 - Thursday, February 25Abstract: My response to Skammdegi is to create The Skammdegi Project, which includes photography, field recordings, knitting circles, a lighted mobile, a concert performance, all culminating in a 30-hour sound installation. During every night of the moon cycle that corresponds to the darkest days from 11 December 2015 to 10 January 2015, I will take a star trail photograph. The darkest, coldest days of winter and Olafsfjordur's distance from city lights and pollution offer an ideal time and place to capture the clearest star trail photographs and catch glimpses of the northern lights. These photographs reveal the movement of the earth and stars that cannot be seen with the naked eye. This movement would be translated into a musical score and transcribed into sound. The star trails and the aurora borealis will become musical gestures. It takes one hour to take a star trail photograph, during which I will take a field recording to be a part of the performance and installation. In the case of inclement weather, the data will still be taken and interpreted accordingly. Stormy days would give rich variation to the sonic landscape. After collecting this data, I will create a one-hour concert performance using the field recordings, flutes, and electronic sounds. Taking the photographs as a musical score, I will transcribe them into sound; every five minutes representing one day in the moon cycle. The movement of the stars will fill these durations as sonic gestures. Throughout the residency, I will hold knitting circles where the community would be invited to knit snowballs with Ãlafoss lopi while listening to the field recordings and sharing the photographs. Ãlafoss lopi is made from Icelandic sheep which is difficult to find outside the country. For centuries, Icelanders have knitted, to keep warm in the cold months. During the knitting circles, I would ask to hear folklore and stories of winters past. These tales would inform how I interpret in the photographs. The community-knitted snowballs would become a part of The Skammdegi Light Mobile, which is the lighted mobile for the sound installation. The entire project culminates in the sound installation. Every photograph and field recording from each day of the moon cycle become one hour of a 30-hour sound installation. I will transcribe the photographs into sound using pre-recorded flutes and electronics. The large light mobile will be the only source of light in the room. Visitors would be allowed to come and go, experiencing different days of the darkest month seen through my translation of the slow movements of celestial bodies. I am happy to modify aspects of the project to accommodate the facilities at Listhus. All together, each aspect of The Skammdegi Project makes audible the movement of the earth and stars during the darkest days, a movement that cannot be seen with the naked eye. By hearing the stories in the knitting circles and living in Olafsfjordur, I will share the story of the starry sky.
Salt Lake City, Utah
Thursday, February 25 - Tuesday, February 2Abstract: Our ability to understand how neurons give rise to behaviour and cognition is in many ways limited by what signals we can record and detect. Local field potential (LFP) recordings have been invaluable for dissecting the role of neural ensembles in computation and communication, and our understanding of neural computation has benefitted immensely from recent work linking high frequency activity (> 80 Hz) to population firing rate “ a major neural code. In addition to firing rate, the balance of excitatory and inhibitory activity (E-I ratio) also plays a critical role in neural computation. However, outside of precise recordings of single neurons, there is still no way to estimate E-I ratio from the population activity. Here, we introduce a method to decompose the LFP into its synaptic and spiking components, by modeling it as a linear superposition of excitatory and inhibitory synaptic potentials, each with characteristic rise and decay time constants. We show that we can retrieve physiologically consistent values for excitatory and inhibitory synaptic current features, as well as the E-I ratio. We validate the model both empirically and in simulation. Given that E-I balance plays a critical role in neural computation, and that imbalances in E-I ratio are implicated in numerous neurological and psychiatric disorders such as schizophrenia and autism, having a reliable method to quickly and easily infer E-I balance has major implications for studying neural coding.
San Diego, CA
Thursday, March 3 - Saturday, March 5Abstract: Purpose: Tobacco use is a cancer-risk behavior in need of intervention for Hispanics/Latinos (H/Ls). Lung cancer is the leading cause of cancer death among H/L men and the second leading cause of cancer death among H/L women. Cigarette smoking is the leading risk factor for lung cancer. Tobacco use among H/Ls may be related to numerous factors at both the individual and environmental level. In an effort to understand how these factors relate to tobacco use among H/Ls, this study examines the relationships among acculturation, the tobacco retail environment, and tobacco use in this population. Methods: Multi-level modeling was used to explore correlates of tobacco use in two community samples of H/L men and women. Participants from both samples (N = 527) completed the Hazuda Acculturation Scale, a multidimensional measure of acculturation, answered two questions about tobacco use, and provided their home address. Neighborhoods were defined using census tracts. Information on the density and proximity of tobacco retailers in one's neighborhood was gathered from the California State Board of Equalization. Results: Controlling for age and income, greater acculturation was significantly associated with increased likelihood of smoking at least 100 cigarettes in one's entire life among H/L men only (b = .32, p = .01). In addition, there was a significant interaction between acculturation and density of tobacco retailers in predicting tobacco use in the total sample (b = -.011, p = .03). There was no significant relationship between acculturation and tobacco use among H/L women or in the total sample. Conclusion: For H/L men only, greater acculturation to the United States was associated with increased tobacco use. In the total sample, results indicated that the density of tobacco retailers in one's neighborhood has a stronger association with tobacco use among less acculturated H/Ls as compared to more acculturated H/Ls. Future studies should examine other factors (family/friend relationships) that may play a role in tobacco use among H/Ls.
Banff, Alberta, Canada
Sunday, February 21 - Friday, February 26Abstract: Depletion of Fat Regulatory T Cells Prevents Age-Associated Insulin Resistance Sagar P. Bapat1,2, Jae Myoung Suh2 , Sungsoon Fang2,3, Sihao Liu2, Yang Zhang1, Albert Cheng1, Carmen Zhou1, Yuqiong Liang2, Mathias LeBlanc2, Christopher Liddle4, Annette R. Atkins2, Ruth T. Yu2, Michael Downes2, Ronald M. Evans2,5, and Ye Zheng1 1Immunobiology and Microbial Pathogenesis Laboratory, 2Gene Expression Laboratory, The Salk Institute for Biological Studies, 3College of Life Sciences, Sejong University, 4Storr Liver Unit, Westmead Millennium Institute, Sydney Medical School, University of Sydney, 5Howard Hughes Medical Institute, The Salk Institute for Biological Studies Age-associated insulin resistance (IR) and obesity-associated IR are two physiologically distinct forms of adult onset diabetes. While macrophage-driven inflammation is a core driver of obesity-associated IR, the underlying mechanisms of the obesity-independent yet highly prevalent age-associated IR are largely unexplored. Comparative adipo-immune profiling (AIP) reveals that fat-resident regulatory T cells, termed fTregs, accumulate in adipose tissue as a function of age, but not obesity. Supporting the existence of two distinct mechanisms underlying IR, mice deficient in fTregs are protected against age-associated IR, yet remain susceptible to obesity-associated IR and metabolic disease. In addition, selective depletion of fTregs via anti-ST2 antibody treatment increases adipose tissue insulin sensitivity. Thus, these findings establish that distinct immune cell populations within adipose tissue underlie aging- and obesity-associated IR and implicate fTregs as adipo-immune drivers and potential therapeutic targets in the treatment of age-associated IR.
Sebastian Diaz Santiago
Monday, March 14 - Friday, March 18Abstract: Controlling skyrmion helicity via engineered Dzyaloshinskii-Moriya interactions Single magnetic skyrmion dynamics in chiral magnets with a spatially inhomogeneous Dzyaloshinskii-Moriya interaction (DMI) is considered. Based on the relation between DMI coupling and skyrmion helicity, it is argued that the latter must be included as an extra degree of freedom in the dynamics of skyrmions. An effective description of the skyrmion dynamics for an arbitrary inhomogeneous DMI coupling is obtained through the collective coordinates method. The resulting generalized Thiele's equation is a dynamical system for the center of mass position and helicity of the skyrmion. It is found that the dissipative tensor and hence the Hall angle become helicity dependent. The skyrmion position and helicity dynamics are fully characterized by our model in two particular examples of engineered DMI coupling: half-planes with opposite-sign DMI and linearly varying DMI. In light of a recent experiment on the magnitude and sign of the DMI, our results constitute the first step toward a more complete understanding of the skyrmion helicity as a new degree of freedom that could be harnessed in future high-density magnetic storage and logic devices.  Tretiakov et al., Phys. Rev. Lett. 100, 127204 (2008).  Shibata et al., Nature Nanotech. 8, 723 (2013).
Port of Spain, Trinidad
Thursday, February 18 - Saturday, February 20Abstract: This essay traces the reincarnation of the Antigone figure in the Caribbean. Focusing on two iterations, Sara Uribe's Antigona Gonzalez (2009) and Luis Rafael Sanchez's La Pasión según Antigona Pérez (1968), I focus on how the Latina Antigona figure both challenges and capitulates to the privileges of the Sophoclean Antigone in her class status and skin color. Antigona becomes an icon of defiance against the state “ for Sanchez, it is the collusion of church, state, and journalists in a fictional dictatorial regime and for Uribe, it is the negligence and impunity of the police and the state in the wake of Mexico's disappeared. In the Caribbean, the Sophoclean tale becomes muddled: her criminality is no longer in question and the burial site is of utmost importance. In both narratives, an aesthetics of loss is entangled with the act of political consciousness. Ultimately, I outline the transatlantic manifestations of Antigone in order to unpack the importance of her claim across the Caribbean.
Monday, March 28 - Friday, April 1Abstract: Three surfactants (Triton X-100, CTAB and SDS), which prevent the emission quenching by reducing dimerization of dyes, was investigated in order to enhance the antenna effect in FRET from three fluorescent donor dyes (TAMRA) to one fluorescent acceptor dye (TexasRed) attached at the middle of 21mer dsDNA. Even though the TexasRed acceptor was absent in the DNA, a strong hydrophobic interaction among the three TAMRAs conjugated on DNA strand caused emission quenching and absorbance shifting, which indicates the dimerization of the TAMRAs. When the inter-TAMRA distance was closer and the TAMRA dyes were on a flexible single strand, the dimerization occurred more seriously. When Triton X-100 was added to the solution, the dimerization did not change due to the neutral charged surfactant, which does not interact with the DNA strand. By increasing the CTAB concentration to 100 uM and above, the neutralized DNA backbone by cationic surfactant induced the aggregation, resulting enhacement of antenna effect due to CTAB molecules covering or sheathing the fluorescent dyes and suppressing the quenching by dimerization. Even though SDS alone did not affect the emission quenching due to repulsive forces between DNA and SDS micelles, with the addition of cations, such as sodium and magnesium, the dimerization and the emission quenching were reduced significantly. It is concluded that SDS micelle, which approached the DNA strand when the repulsive force was screened by the cations, sheathes/shields/insulates three TAMRA dyes conjugated on a DNA strand, reducing the dimerization and thus recovering the fluorescent emission. When the three TAMRA conjugated DNA strand and the TexasRed conjugated complementary strand were hybridized without surfactants, formation of dimers such as homodimer by donor-donor stacks and heterodimer by donor-acceptor stacks caused the emission quenching and low antenna effect in the DNA FRET structure. Similar results as three TAMRA conjugated DNA strand without acceptor dye, SDS micelles with magnesium reduced dimerization and enhanced the antenna effect between dyes conjugated on DNA. Overall, this study opens the door for using surfactants with cations to reduce the quenching by dimerization and to improve the antenna effect in DNA FRET structures containing multi-donor and acceptor fluorescent dye molecules.
Friday, March 4 - Tuesday, March 8Abstract: There are 4 abstracts that I will be presenting at the conference: ABSTRACT #1: Background: While atopic dermatitis (AD) affects all children with features of pruritus & chronic, relapsing course, some clinical manifestations do vary. However, there is a lack of studies that have detailed lesional morphology, distribution, & other characteristics of AD across different skin types & racial & ethnic backgrounds, particularly in minority populations. The current study was designed to systematically examine these features. Methods: Subjects age â‰¤10 years were recruited, with a focus on enrolling patients with active inflammatory lesions & minimal to no prior/recent treatment. Ethnicity, race, skin type, medical & family history, disease severity, aggravating factors, & life quality index were recorded. A systematic exam assessed lesional morphology, location, & distribution, along with presence of secondary findings such as Hanifin and Rajka's major & minor diagnostic criteria. Results: This is an interim assessment of the first 55 subjects enrolled (median age 2.1 years). They included 18 Hispanic Whites (HW), 12 Non-Hispanic Whites (W), 11 Asians (A), 3 Pacific Islanders (PI), 5 Non-Hispanic Blacks (B), 2 Hispanic Blacks (HB), 3 Asian/Whites (AW), & 1 child of multiple racial backgrounds. Median Rajka Langeland score was 6. Most cases were chronic & persistent (61.8%) or worsening (36.4%), as compared to intermittent. Among comorbidities, allergic rhinitis was most common in all races. Food allergies were also common, except in PI and B. The weather (85.5%) & skin irritants (45.5%) were the most prevalent aggravating factors. PI had the highest median % body surface area involved (38%) & itch severity scores; they reported AD more often aggravated by skin infections, while AD of A & HW was most affected by other non-skin infections. The face was the most common site of involvement for all subjects, with less erythema noted in darker skin types. Orbital darkening was common throughout, while infraorbital folds were less common in A & PI. White dermatographism was only noted in W children (25%) & dirty neck only in PI (67%). Papular lesions tended to be below the neck in B and PI. Perifollicular accentuation & post-inflammatory pigmentary changes were mainly in darker skin types. Conclusion: This investigation confirms some AD clinical features as universal, while others have a predilection for particular skin types & racial & ethnic backgrounds. Recognizing shared and unique features of AD may also impact management. ABSTRACT #2: A 7-year-old Hispanic girl presented to Pediatric Dermatology for evaluation of congenital hypertrichosis. Cutaneous examination revealed coarse facies and generalized hypertrichosis with thick dark hairs covering the preauricular cheeks, back, and upper and lower extremities. The patient also had a history of mild learning disability, scoliosis, and asymptomatic structural cardiac abnormalities (aortic root dilation and patent ductus arteriosus), raising suspicion for Cantu Syndrome (CS). Therefore, whole exome gene sequencing was performed and revealed a heterozygous de-novo ABCC9 gene mutation (c.3460C>T (p.Arg1154Trp)) (chromosome 12p12.1), a mutation variant previously reported in association with four unrelated CS patients. Cantu Syndrome (also known as hypertrichosis-osteochondrodysplasia-cardiomegaly syndrome) is an extremely rare autosomal dominant disorder. Patients typically present with generalized congenital hypertrichosis, macrosomia at birth, macrocephaly, coarse facial features, cardiomegaly, skeletal abnormalities, and developmental delay. Reported cardiac abnormalities include cardiac enlargement, concentric hypertrophy of the ventricles, pulmonary hypertension, pericardial effusion, patent ductus arteriosus, and bicuspid aortic valves. Aortic root dilatation, observed in our patient, has not been previously reported in the literature. Many cases of CS are due to heterozygous ABCC9 gene mutations. These mutations are thought to confer an activating mutation in SUR2, a subunit constituent of the sulfonylurea ATP-regulated potassium channel, leading to over-activation of the channel. Of note, sulfonylureas antagonize SUR2, and in follicular keratinocytes, this activity results in shortening of the anagen phase in cultured hair follicles. Based on this predicted molecular mechanism, topical sulfonylurea has been proposed as a potential novel treatment approach for hypertrichosis. Therefore, we are investigating and developing a compounded topical sulfonylurea as a possible safe, low-cost treatment for this patient's hypertrichosis. ABSTRACT #3: An 8-year-old Hispanic female presented to Pediatric Dermatology with an asymptomatic, recurrent rash on the bilateral temporal face, chest, and shoulders present for 5 months. Physical examination revealed several small 1-2 mm white dome-shaped papules with central umbilication on the face and chest. There were also rare, scattered erythematous papules and papulovesicles, with several ovoid shallow scars on the bilateral temples, cheeks and nose. Biopsy was performed and revealed superficial and deep perivascular and periadnexal infiltrates. . Immunohistochemical staining utilizing EBV LMP-1 staining was positive in many perifollicular epithelia. Complete blood count (CBC) and liver function tests (LFTs) were within normal limits. EBV serologic testing was consistent with recent infection. Ophthalmologic evaluation revealed a granulomatous uveitis. The patient's clinical and laboratory findings were felt to be consistent with EBV-associated hydroa vacciniforme. Hydroa vacciniforme (HV) is a rare pediatric photodermatitis characterized by symmetric papulovesicular lesions that heal with varioliform scarring on sun-exposed areas. It can be associated with EBV infections, particularly if necrotic lesions are present. This EBV-associated HV may manifest as a more severe form of disease that is associated with lymphoproliferative disorders, such as hydroa vacciniforme-like lymphoma (HVLL). HVLL is a rare EBV positive cutaneous T-cell lymphoma that usually occurs in children. In addition to the typical lesions seen in HV, HVLL may present with facial edema, ulcerative lesions, large hemorrhagic bullae, and atrophic scars on both sun-exposed and non-sun-exposed skin. Therefore, sun exposure is not thought to induce HVLL. HV more commonly affects males who also have a later onset and longer disease course (mean duration of HV is 9 years). Patients may experience pruritus or a burning sensation a few hours or days after sun exposure, followed by the onset of erythematous macules that progress to necrotic crusts. HV is rarely associated with ocular and oral involvement as well as deformities of the hands, ears, and nose that are typically related to scarring. Ocular manifestations include photophobia, conjunctivitis, anterior uveitis, keratitis, and corneal opacities. Laboratory evaluation, including CBC with differential and LFTs, may identify severe HV and its variants which can be associated with high fevers, facial swelling, liver damage, and hematologic abnormalities. Sun protection is vital for the management of HV. Suggested treatment for EBV-associated HV includes acyclovir (28-72 mg/kg/ day, divided into 2-5 doses) or valacyclovir (60 mg/kg/day divided twice daily) for 2-4 week periods, or continuously. Our patient was treated with acyclovir 40mg/kg/day divided twice daily for 4 weeks, along with sun protection. ABSTRACT #4: Background: Eosinophilic esophagitis (EE) causes dysphagia, vomiting, and failure to thrive. Although EE is difficult to treat, it is important to identify and eliminate food antigens that trigger an inflammatory response. Allergic contact dermatitis (ACD) is a delayed type IV hypersensitivity reaction, and systemic contact dermatitis occurs when systemic exposure causes an acute dermatitis in a topically sensitized individual. Skin prick, patch, and serum allergy tests aid in allergy diagnosis; however, atopy patch testing is most reliable in detecting delayed allergic reactions to allergens present in food. Balsam of Peru, nickel sulfate, and propylene glycol are common allergens for which a positive patch test may indicate a food allergy to tomatoes, chocolate, and food preservatives, respectively. Thus, these tests are important in evaluating food antigens whose prior skin exposure facilitates allergic sensitization that later incites EE. Overall, few studies have specifically evaluated the associations between EE and ACD. Purpose: To study clinical associations between EE and ACD in children. Methods: Retrospective review of patients diagnosed with EE and ACD at a single academic children's hospital between 1/1/08 and 1/15/15. Results: The majority of patients were male (80%), Non-Hispanic (82.9%), and Caucasian (71.4%). Contact allergens included latex (11.4%), tomato (11.4%), adhesive tape (8.6%), disperse blue 106 (5.7%), coconut oil (2.9%), quaternium-15 (2.9%), poison oak (2.9%), PPD (2.9%), budesonide (2.9%), bronopol (2.9%), MCI/MI (2.9%), and/or egg (2.9%). Many were allergic to grass (31.4%), pollen (28.6%), cat (28.6%), mold (17.1%), dog (17.1%), dust (14.3%), ragweed (14.3%), and/or trees (14.3%). Food allergies included egg (42.9%), dairy (28.6%), tree nuts (20%), peanuts (20%), fish (14.3%), chicken (14.3%), bananas (8.6%), wheat (8.6%), soy (8.6%), oats (8.6%), and /or shellfish (5.7%). Of those with latex ACD, 50% were allergic to egg and/or chicken, and 25% to mold, pollen, tree nuts, and/or peanuts. 50% of those with tomato ACD were also allergic to grass, dog, cat, egg, and/or peanuts. Of those with adhesive tape ACD, 66.7% were allergic to dog and/or cat, and 33.3% to grass, pollen, dust, egg, and/or fish. Patients had a history of food allergy (80%), asthma (60%), allergic rhinitis (60%), and AD (40%); a family history of asthma (42.9%), AD (31.4%), ACD (31.4%), allergic rhinitis (31.4%), and food allergy (20%). Conclusion: Cutaneous sensitization is a common underlying mechanism of both EE and ACD. Therefore, these results may assist physicians to more accurately treat, evaluate associated risks and comorbidities, and identify the role of patch testing in these children.
Sunday, February 21 - Friday, February 26Abstract: All-solid-state batteries offer high energy density and reduced capacity fade, and are a safer alternative to the conventional liquid electrolyte batteries currently being manufactured. Further, thin film geometries are an ideal platform for fundamental studies regarding the compatibility of electrolyte and electrode materials, allowing observation of interfacial processes that may be used to describe systematic limitations of solid-state batteries on the production scale. We report progress on the synthesis of amorphous electrolyte lithium lanthanum titanate (LLTO), exhibiting ionic conductivities of > 10^-3 S/cm^2 , with the goal of incorporating this electrolyte into thin film batteries. Further, we have fabricated spinel lithium nickel manganese oxide (LNMO)/LiPON thin film batteries, which was recently shown to exhibit remarkable cyclability . Using a focused ion beam, we have fabricated electrochemically active nanobatteries. Our group has recently demonstrated application of a galvanostatic in situ STEM/EELS technique to observe the dynamic behavior of the electrochemically active thin film nanobatteries, uncovering mechanisms otherwise hidden from ex situ cycling . We aim to apply this novel technique to a range of thin film configurations to elucidate the properties of solid-state interfaces during battery cycling.  O. Bohnke, The fast lithium-ion conducting oxides Li3xLa2/3 âˆ’ xTiO3 from fundamentals to application, Solid State Ionics, 179 (2008) 9-15.  J. Li, C. Ma, M. Chi, C. Liang, N.J. Dudney, Solid Electrolyte: the Key for High-Voltage Lithium Batteries, Advanced Energy Materials, 5 (2015) 1401408.  Z. Wang, D. Santhanagopalan, W. Zhang, F. Wang, H. Xin, K. He, J. Li, N. Dudney, Y.S. Meng, In situ STEM/EELS Observation of Nanoscale Interfacial Phenomena in All-Solid-State Batteries, Submitted.
Tiago Ferreira Leao
Four Points Sheraton/Holiday Inn Express, Ventura, CA
Sunday, March 6 - Friday, March 11Abstract: The importance of natural products to physiology and medicine is legendary, and has revolutionized human health on a global scale. This importance was recently globally recognized with the 2015 Nobel Prize for the discovery of two important natural products, avermectin and artemisinin. Despite these successes, classical natural products' isolation efforts do not always lead to new and highly bioactive compounds. Often times the process leads to the re-discovery of a known compound or sometimes the discovery of a new compound with no detectable biological activities. Combined with this, the genomics revolution has revealed that the number and chemical diversity of natural products previously found are only the tip of the iceberg, and there are many new expectations of successful drug discovery from the natural products field. Nevertheless, the promises levered by the genomic revolution have not yet yielded a significantly increased number of new and bioactive natural products, and this can be attributed to the existence of biological, chemical and computational challenges. One of the computational challenges is the difficulty to obtain complete genomes from non-axenic cultures, which is the case of most filamentous cyanobacterial strains today. For example, tropical filamentous cyanobacteria from the genus Moorea have already yielded the discovery of over 190 natural products, although to the present time, there are no complete genomes available in public databases for this genus (NCBI, JGI/IMG and so on). Moreover, another main computational challenge is the lack of efficient and readily available methods to group biosynthetic gene clusters (BGCs) into families. Therefore, even the complete genomes that are filled with many BGCs can not be properly explored, and this inhibits the discovery of new and bioactive compounds. In this project, we tackle these two computational challenges, and to date have obtained the first complete genome from a tropical filamentous cyanobacterium and have developed a network approach to better analyze BGCs. We also used this reference genome to improve the quality of three other genomes from the same genus. This networking approach resulted in a robust genome comparison of the BGCs, providing insights into their distribution, evolution, and regulation (to be further explored via transcriptomic analysis). These data are also proving useful in selecting the most suitable isolation techniques, such as combining genomics with molecular networking, isotope labeling studies (e.g. the genomisotopic approach), use of chemical probes to shift LCMS peaks, and homologous and heterologous expression experiments.
Monday, March 28 - Friday, April 1Abstract: Mechanical Behavior of Tubular Structures in Horns and Hooves Tubular structure are one of the most impact resistant and energy absorbent structural designs and although studied for many years, remains an attractive research interest. Among the biological materials that have tubular structures, horns and hooves are excellent examples of impact resistant structures that have evolved for fighting or galloping of bovidae and equidae, respectively. Microstructures and mechanical behavior of the bighorn sheep (Ovis Canadensis) horn and African zebra (Equus burchelli) hoof were studied to examine mechanisms of impact resistant. Hooves and horns are composed of “keratin crystalline intermediate filaments embedded in an amorphous matrix. Both have a tubular structure and a surrounding laminated structure. Optical and electronic microscope images showed the shape of tubule cross section in both horn and hoof are ellipses, 80cm (major axis) and 40cm (minor axis). However, the porosity in the horn is 7%, while in the hoof is 3.5%. The intertubular lamellae area is much larger in the hoof than that in the horn. Since anisotropy is an important factor in material properties, mechanical properties of horns and hooves were evaluated in three orthogonal directions (longitudinal, transverse and radial). Quasi-static compression test results showed strength and Young's modulus were much higher in longitudinal and transverse direction than that in radial direction, while the radial direction was more energy absorbent because of the tubule collapse. Comparing horn and hoof structures, although the porosity in horn is two times that of the hoof, the compressive yield strength and Young's modulus are higher in the horns in all the three directions, which demonstrated that horn structure was more energy absorbent in a quasi-static load. To determine how porosity affects the mechanical properties of tubular structures, 3D printed models of two different tubular densities (7% and 3.5%) were fabricated. At the same time, quasi-static and dynamic simulation of these two kinds of tubular models were carried out using finite element analysis, which showed a more uniformly distributed stress in transverse direction, leading to a higher stiffness. Kolsky bar dynamic test results as well as further finite element analysis on the tubular models will be presented. This work is supported by funding provided by a Multi-University Research Initiative through the Air Force Office of Scientific Research (AFOSR-FA9550-15-1-0009).