Matching Items (135)
Description
X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy. Scattering patterns resulting from single particles were selected and compiled into a dataset which can be valuable for algorithm developments in single particle scattering research.
ContributorsLi, Xuanxuan (Author) / Chiu, Chun-Ya (Author) / Wang, Hsiang-Ju (Author) / Kassemeyer, Stephan (Author) / Botha, Sabine (Author) / Shoeman, Robert L. (Author) / Lawrence, Robert (Author) / Kupitz, Christopher (Author) / Kirian, Richard (Author) / James, Daniel (Author) / Wang, Dingjie (Author) / Nelson, Garrett (Author) / Messerschmidt, Marc (Author) / Boutet, Sebastien (Author) / Williams, Garth J. (Author) / Hartman, Elisabeth (Author) / Jafarpour, Aliakbar (Author) / Foucar, Lutz M. (Author) / Barty, Anton (Author) / Chapman, Henry (Author) / Liang, Mengning (Author) / Menzel, Andreas (Author) / Wang, Fenglin (Author) / Basu, Shibom (Author) / Fromme, Raimund (Author) / Doak, R. Bruce (Author) / Fromme, Petra (Author) / Weierstall, Uwe (Author) / Huang, Michael H. (Author) / Spence, John (Author) / Schlichting, Ilme (Author) / Hogue, Brenda (Author) / Liu, Haiguang (Author) / ASU Biodesign Center Immunotherapy, Vaccines and Virotherapy (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Molecular Sciences (Contributor) / Department of Physics (Contributor) / School of Life Sciences (Contributor)
Created2017-04-11
Description
Background
Obese Latino adolescents are disproportionately impacted by insulin resistance and type 2 diabetes. Prediabetes is an intermediate stage in the pathogenesis of type 2 diabetes and represents a critical opportunity for intervention. However, to date, no diabetes prevention studies have been conducted in obese Latino youth with prediabetes, a highly vulnerable and underserved group. Therefore, we propose a randomized-controlled trial to test the short-term (6-month) and long-term (12-month) efficacy of a culturally-grounded, lifestyle intervention, as compared to usual care, for improving glucose tolerance and reducing diabetes risk in 120 obese Latino adolescents with prediabetes.
Methods
Participants will be randomized to a lifestyle intervention or usual care group. Participants in the intervention group will attend weekly nutrition and wellness sessions and physical activity sessions twice a week for six months, followed by three months of booster sessions. The overall approach of the intervention is framed within a multilevel Ecodevelopmental model that leverages community, family, peer, and individual factors during the critical transition period of adolescence. The intervention is also guided by Social Cognitive Theory and employs key behavioral modification strategies to enhance self-efficacy and foster social support for making and sustaining healthy behavior changes. We will test intervention effects on quality of life, explore the potential mediating effects of changes in body composition, total, regional, and organ fat on improving glucose tolerance and increasing insulin sensitivity, and estimate the initial incremental cost effectiveness of the intervention as compared with usual care for improving glucose tolerance.
Discussion
The proposed trial builds upon extant collaborations of a transdisciplinary team of investigators working in concert with local community agencies to address critical gaps in how diabetes prevention interventions for obese Latino youth are developed, implemented and evaluated. This innovative approach is an essential step in the development of scalable, cost-effective, solution oriented programs to prevent type 2 diabetes in this and other populations of high-risk youth.
Obese Latino adolescents are disproportionately impacted by insulin resistance and type 2 diabetes. Prediabetes is an intermediate stage in the pathogenesis of type 2 diabetes and represents a critical opportunity for intervention. However, to date, no diabetes prevention studies have been conducted in obese Latino youth with prediabetes, a highly vulnerable and underserved group. Therefore, we propose a randomized-controlled trial to test the short-term (6-month) and long-term (12-month) efficacy of a culturally-grounded, lifestyle intervention, as compared to usual care, for improving glucose tolerance and reducing diabetes risk in 120 obese Latino adolescents with prediabetes.
Methods
Participants will be randomized to a lifestyle intervention or usual care group. Participants in the intervention group will attend weekly nutrition and wellness sessions and physical activity sessions twice a week for six months, followed by three months of booster sessions. The overall approach of the intervention is framed within a multilevel Ecodevelopmental model that leverages community, family, peer, and individual factors during the critical transition period of adolescence. The intervention is also guided by Social Cognitive Theory and employs key behavioral modification strategies to enhance self-efficacy and foster social support for making and sustaining healthy behavior changes. We will test intervention effects on quality of life, explore the potential mediating effects of changes in body composition, total, regional, and organ fat on improving glucose tolerance and increasing insulin sensitivity, and estimate the initial incremental cost effectiveness of the intervention as compared with usual care for improving glucose tolerance.
Discussion
The proposed trial builds upon extant collaborations of a transdisciplinary team of investigators working in concert with local community agencies to address critical gaps in how diabetes prevention interventions for obese Latino youth are developed, implemented and evaluated. This innovative approach is an essential step in the development of scalable, cost-effective, solution oriented programs to prevent type 2 diabetes in this and other populations of high-risk youth.
ContributorsSoltero, Erica (Author) / Konopken, Yolanda P. (Author) / Olson, Micah (Author) / Keller, Colleen (Author) / Castro, Felipe (Author) / Williams, Allison (Author) / Patrick, Donald L. (Author) / Ayers, Stephanie (Author) / Hu, Houchun H. (Author) / Sandoval, Matthew (Author) / Pimentel, Janiel (Author) / Knowler, William C. (Author) / Frick, Kevin D. (Author) / Shaibi, Gabriel (Author) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Center for Health Promotion and Disease Prevention (Contributor) / College of Public Service and Community Solutions (Contributor) / Southwest Interdisciplinary Research Center (Contributor) / School of Social Work (Contributor)
Created2017-03-16
Description
Despite their low cost and high nutrient density, the contribution of eggs to nutrient intake and dietary quality among Mexican-American postpartum women has not been evaluated. Nutrient intake and dietary quality, as assessed by the Healthy Eating Index 2010 (HEI-2010), were measured in habitually sedentary overweight/obese (body mass index (BMI) = 29.7 ± 3.5 kg/m[superscript 2]) Mexican-American postpartum women (28 ± 6 years) and compared between egg consumers (n = 82; any egg intake reported in at least one of three 24-h dietary recalls) and non-consumers (n = 57). Egg consumers had greater intake of energy (+808 kJ (193 kcal) or 14%; p = 0.033), protein (+9 g or 17%; p = 0.031), total fat (+9 g or 19%; p = 0.039), monounsaturated fat (+4 g or 24%; p = 0.020), and several micronutrients than non-consumers. Regarding HEI-2010 scores, egg consumers had a greater total protein foods score than non-consumers (4.7 ± 0.7 vs. 4.3 ± 1.0; p = 0.004), and trends for greater total fruit (2.4 ± 1.8 vs. 1.9 ± 1.7; p = 0.070) and the total composite HEI-2010 score (56.4 ± 12.6 vs. 52.3 ± 14.4; p = 0.082). Findings suggest that egg intake could contribute to greater nutrient intake and improved dietary quality among postpartum Mexican-American women. Because of greater energy intake among egg consumers, recommendations for overweight/obese individuals should include avoiding excessive energy intake and incorporating eggs to a nutrient-dense, fiber-rich dietary pattern.
ContributorsVega Lopez, Sonia (Author) / Pignotti, Giselle (Author) / Todd, Michael (Author) / Keller, Colleen (Author) / College of Health Solutions (Contributor) / School of Nutrition and Health Promotion (Contributor) / College of Public Service and Community Solutions (Contributor) / Southwest Interdisciplinary Research Center (Contributor) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor)
Created2015-10-02
Description
Viral protein U (Vpu) is a type-III integral membrane protein encoded by Human Immunodeficiency Virus-1 (HIV- 1). It is expressed in infected host cells and plays several roles in viral progeny escape from infected cells, including down-regulation of CD4 receptors. But key structure/function questions remain regarding the mechanisms by which the Vpu protein contributes to HIV-1 pathogenesis. Here we describe expression of Vpu in bacteria, its purification and characterization. We report the successful expression of PelB-Vpu in Escherichia coli using the leader peptide pectate lyase B (PelB) from Erwinia carotovora. The protein was detergent extractable and could be isolated in a very pure form. We demonstrate that the PelB signal peptide successfully targets Vpu to the cell membranes and inserts it as a type I membrane protein. PelB-Vpu was biophysically characterized by circular dichroism and dynamic light scattering experiments and was shown to be an excellent candidate for elucidating structural models.
ContributorsDeb, Arpan (Author) / Johnson, William (Author) / Kline, Alexander (Author) / Scott, Boston (Author) / Meador, Lydia (Author) / Srinivas, Dustin (Author) / Martin Garcia, Jose Manuel (Author) / Dorner, Katerina (Author) / Borges, Chad (Author) / Misra, Rajeev (Author) / Hogue, Brenda (Author) / Fromme, Petra (Author) / Mor, Tsafrir (Author) / ASU Biodesign Center Immunotherapy, Vaccines and Virotherapy (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Biodesign Institute (Contributor) / School of Molecular Sciences (Contributor) / Applied Structural Discovery (Contributor) / Personalized Diagnostics (Contributor)
Created2017-02-22
Description
Spaceflight and spaceflight analogue culture enhance the virulence and pathogenesis-related stress resistance of the foodborne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium). This is an alarming finding as it suggests that astronauts may have an increased risk of infection during spaceflight. This risk is further exacerbated as multiple studies indicate that spaceflight negatively impacts aspects of the immune system. In order to ensure astronaut safety during long term missions, it is important to study the phenotypic effects of the microgravity environment on a range of medically important microbial pathogens that might be encountered by the crew. This ground-based study uses the NASA-engineered Rotating Wall Vessel (RWV) bioreactor as a spaceflight analogue culture system to grow bacteria under low fluid shear forces relative to those encountered in microgravity, and interestingly, in the intestinal tract during infection. The culture environment in the RWV is commonly referred to as low shear modeled microgravity (LSMMG). In this study, we characterized the stationary phase stress response of the enteric pathogen, Salmonella enterica serovar Enteritidis (S. Enteritidis), to LSMMG culture. We showed that LSMMG enhanced the resistance of stationary phase cultures of S. Enteritidis to acid and thermal stressors, which differed from the LSSMG stationary phase response of the closely related pathovar, S. Typhimurium. Interestingly, LSMMG increased the ability of both S. Enteritidis and S. Typhimurium to adhere to, invade into, and survive within an in vitro 3-D intestinal co-culture model containing immune cells. Our results indicate that LSMMG regulates pathogenesis-related characteristics of S. Enteritidis in ways that may present an increased health risk to astronauts during spaceflight missions.
ContributorsKoroli, Sara (Author) / Nickerson, Cheryl (Thesis director) / Barrila, Jennifer (Committee member) / Ott, C. Mark (Committee member) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The International Space Station (ISS) utilizes recycled water for consumption, cleaning and air humidity control. The Environmental Control and Life Support Systems (ECLSS) have been rigorously tested at the NASA Johnson Space Center. Despite the advanced engineering of the water recovery system, bacterial biofilms have been recovered from this potable water source. Microbial contamination of potable water poses a potential threat to crew members onboard the ISS. Because astronauts have been found to have compromised immune systems, bacterial strains that would not typically be considered a danger must be carefully studied to better understand the mechanisms enabling their survival, including polymicrobial interactions. The need for a more thorough understanding of the effect of spaceflight environment on polymicrobial interactions and potential impact on crew health and vehicle integrity is heightened since 1) several potential pathogens have been isolated from the ISS potable water system, 2) spaceflight has been shown to induce unexpected alterations in microbial responses, and 3) emergent phenotypes are often observed when multiple bacterial species are co- cultured together, as compared to pure cultures of single species. In order to address these concerns, suitable growth media are required that will not only support the isolation of these microbes but also the ability to distinguish between them when grown as mixed cultures. In this study, selective and/or differential media were developed for bacterial isolates collected from the ISS potable water supply. In addition to facilitating discrimination between bacteria, the ideal media for each strain was intended to have a 100% recovery rate compared to traditional R2A media. Antibiotic and reagent susceptibility and resistance tests were conducted for the purpose of developing each individual medium. To study a wide range of targets, 12 antibiotics were selected from seven major classes, including penicillin, cephalosporins, fluoroquinolones, aminoglycosides, glycopeptides/lipoglycopeptides, macrolides/lincosamides/streptogramins, tetracyclines, in addition to seven unclassified antibiotics and three reagents. Once developed, medium efficacy was determined by means of growth curve experiments. The development of these media is a critical step for further research into the mechanisms utilized by these strains to survive the harsh conditions of the ISS water system. Furthermore, with an understanding of the complex nature of these polymicrobial communities, specific contamination targeting and control can be conducted to reduce the risk to crew members. Understanding these microbial species and their susceptibilities has potential application for future NASA human explorations, including those to Mars.
ContributorsKing, Olivia Grace (Author) / Nickerson, Cheryl (Thesis director) / Barrila, Jennifer (Committee member) / Ott, Mark (Committee member) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
The importance of second language learning in today’s ever-increasing globalized world is becoming ever more paramount. Despite seeming trends which indicate aversion to globalization, the international phenomenon which describes the connection made between peoples and cultures, will only increase its influence in coming years. With the advances globalization has made, it is becoming more important to learn and study foreign languages in order to keep abreast of this trend and not be left behind by globalization. Why electronic translation is not so viable in the long run (at least currently) is that culture and syntax are not things which can be simply ascertained via mediums such as application use. Due to the fact that advanced language proficiency is considered to be an integral piece towards stronger sentiments of “integration” (i.e. Syrian refugees integrating into EU and US) it is of more importance that increasing second language proficiency receives the adequate study and implementation to reflect a more cohesive globalized world. Accompanying this necessity is the simple fact that adult second language learners often struggle to overcome difficulty to the challenging yet rewarding task of learning and eventually mastering a second language.
To truly understand the difficulty some adult second language learners have with learning a second language it can be helpful to compare second language acquisition to how one naturally, and seemingly effortlessly in many cases, acquires their native language. How can a comparative analysis of how native speakers and adult second language learners each learn their first and second language respectively be successfully converted to a specific means of assisting adult second language learners achieve the highest level of possible fluency? In order to more accurately propose a viable solution to the overarching question, the following three questions have been proposed as a means to springboard into better understanding the nature of the main topic.
The points to consider while analyzing the main question throughout this analysis are as follows: How would it be best for an adult second language learner to achieve the same level off proficiency as a native speaker of a given language whom has been exposed to all of its intricacies since birth? At what point exactly is someone considered to have the same level of proficiency which a native speaker of a given language would have and how does that differ from being a heritage speaker? With the final supporting question being: What type of learning would be best suited in helping a heritage speaker (someone who learns a language in the home by virtue of their heritage) or adult second language learner to become highly proficient in a second language?
In order to propose a wide variety of integration between these questions with the conjoined purpose of answering the inquiry of this thesis, many different sources supporting each of the above questions will contain certain overlap, providing a clear basis for constructing a tri-fold argument in answering the thesis question as acutely as possible. In regards to the first question, the question of “proficiency” will be a subsection committed to understanding the nature of how language proficiency works and at what point (if ever) one can ever be considered “highly proficient” in a second language.
All three exploratory questions are compatible with a theory known as Critical Period Theory, a theory in linguistics proposed by Montreal neurologist Wilder Penfield, which states, “There is a critical age, before puberty, that one must learn language. If one has not learned to speak before puberty it is much more difficult, and sometimes impossible, to learn language and speak in a meaningful way.” The overlap which this method binds to Universal Grammar is a rather close-knit relationship. Research composed by certain linguists suggest that “children are born with a certain universal grammar wired into their brains.” This will be compared and cross-examined to a higher degree in a later section of the paper.
The importance of Universal Grammar in relation to Critical Period Theory cannot be overstated. Universal Grammar in relation to the second language Critical Period Theory will help explain at which point, someone is considered to be a “native speaker” of a given language. The third question posed of how would it be best for heritage and second language learners to increase their proficiency in a second language really touches on both of these theories in regards to at which age someone is exposed to a specific language in addition to how Universal Grammar affects the development of second language acquisition. In the realm of perpetually working towards mitigating an answer to this analysis’s thesis, the connecting thread or “roter Faden”, as it is said in German, will be the integrative domain the above questions will have on arriving to a clearer understanding of the nature of how a comparative analysis of second language learners and mother-tongue speakers can expedite the language learning process of second language learners, using techniques of native speakers which they inherently pick-up.
To truly understand the difficulty some adult second language learners have with learning a second language it can be helpful to compare second language acquisition to how one naturally, and seemingly effortlessly in many cases, acquires their native language. How can a comparative analysis of how native speakers and adult second language learners each learn their first and second language respectively be successfully converted to a specific means of assisting adult second language learners achieve the highest level of possible fluency? In order to more accurately propose a viable solution to the overarching question, the following three questions have been proposed as a means to springboard into better understanding the nature of the main topic.
The points to consider while analyzing the main question throughout this analysis are as follows: How would it be best for an adult second language learner to achieve the same level off proficiency as a native speaker of a given language whom has been exposed to all of its intricacies since birth? At what point exactly is someone considered to have the same level of proficiency which a native speaker of a given language would have and how does that differ from being a heritage speaker? With the final supporting question being: What type of learning would be best suited in helping a heritage speaker (someone who learns a language in the home by virtue of their heritage) or adult second language learner to become highly proficient in a second language?
In order to propose a wide variety of integration between these questions with the conjoined purpose of answering the inquiry of this thesis, many different sources supporting each of the above questions will contain certain overlap, providing a clear basis for constructing a tri-fold argument in answering the thesis question as acutely as possible. In regards to the first question, the question of “proficiency” will be a subsection committed to understanding the nature of how language proficiency works and at what point (if ever) one can ever be considered “highly proficient” in a second language.
All three exploratory questions are compatible with a theory known as Critical Period Theory, a theory in linguistics proposed by Montreal neurologist Wilder Penfield, which states, “There is a critical age, before puberty, that one must learn language. If one has not learned to speak before puberty it is much more difficult, and sometimes impossible, to learn language and speak in a meaningful way.” The overlap which this method binds to Universal Grammar is a rather close-knit relationship. Research composed by certain linguists suggest that “children are born with a certain universal grammar wired into their brains.” This will be compared and cross-examined to a higher degree in a later section of the paper.
The importance of Universal Grammar in relation to Critical Period Theory cannot be overstated. Universal Grammar in relation to the second language Critical Period Theory will help explain at which point, someone is considered to be a “native speaker” of a given language. The third question posed of how would it be best for heritage and second language learners to increase their proficiency in a second language really touches on both of these theories in regards to at which age someone is exposed to a specific language in addition to how Universal Grammar affects the development of second language acquisition. In the realm of perpetually working towards mitigating an answer to this analysis’s thesis, the connecting thread or “roter Faden”, as it is said in German, will be the integrative domain the above questions will have on arriving to a clearer understanding of the nature of how a comparative analysis of second language learners and mother-tongue speakers can expedite the language learning process of second language learners, using techniques of native speakers which they inherently pick-up.
ContributorsRoselius, Thomas Jacob (Author) / Lee, Sara (Thesis director) / Reves, Christiane (Committee member) / College of Public Service and Community Solutions (Contributor) / College of Integrative Sciences and Arts (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Blood donations today undergo extensive screening for transfusion transmitted infections (TTI) since the discovery of the first infectious agent in the early 1900s. Nucleic Acid Testing (NAT) is a serological test used widely in disease detection. NAT is known to rapidly and effectively detect pathogenic genomic material in blood by reducing the "window period" of infection. However, NAT produces false negative results for disease positive samples posing a risk of disease transmission. Therefore, NAT is used in conjunction with the Enzyme-Linked Immunosorbent Assay (ELISA) to mitigate these risks. However, the ELISA assay also poses the same risk as NAT. This study proposes immunosignaturing as an alternative serological test that may combat this risk and investigates whether it would be more effective than other standardized serological tests in disease detection. Immunosignaturing detects antibodies by utilizing a microarray of randomized peptide sequences. Immunosignaturing provides information about an individual's immune health from the pattern of reactivity of antibody-peptide binding. Unlike ELISA and NAT, immunosignaturing can be programmed to detect any disease and detect multiple diseases simultaneously. Using ELISA, NAT, and immunosignaturing, immune profiles of asymptomatic patients were constructed for 10 different classes of blood borne diseases. A pattern of infection was identified for each disease and the sensitivity and specificity of these assays were assessed relative to each other. Results indicate that immunosignaturing can be a viable diagnostic tool in blood testing. Immunosignatures demonstrated increased sensitivity and specificity compared to ELISA and NAT in discerning disease positive and negative samples within and across different classes of disease.
ContributorsSharma, Megumi (Author) / McFadden, Grant (Thesis director) / Nickerson, Cheryl (Committee member) / Green, Alex (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This study examined the type and frequency of questions asked by attorneys in cases of children alleging sexual abuse. Of interest was whether child age would affect the questions asked. The participants included 25 child witnesses testifying in criminal trials in Maricopa County over a recent ten-year period. Children were placed into two groups: younger (five to seven-year-olds) and older (eight to nine-year-olds). Every question asked, and answer provided, during children's testimony, was systematically and reliably coded for the content of the interaction. Attorneys exhibited developmental sensitivity, varying the amount of question they asked across content areas by the age of the child. In addition, attorneys varied in what they asked about: the prosecution focused more on the plausibility of abuse, whereas the defense focused more on how others may have suggestively influenced the child's report. Both attorneys were equally concerned about the consistency of narratives. The findings from the present study have direct policy implications for how attorneys structure their arguments, both in an attempt to establish, and question, children's credibility in these important cases. Keywords: children, age, suggestibility, consistency, inconsistency, plausibility
ContributorsHogan, Caitlyn Rose (Author) / Stolzenberg, Stacia (Thesis director) / Fradella, Hank (Committee member) / College of Public Service and Community Solutions (Contributor) / School of Criminology and Criminal Justice (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Throughout history, terrorism has had major effects on tourists and tourism destinations that are targeted. When terrorists execute an attack in order to communicate a message, resulting impacts go far beyond lives lost. Included in these impacts is the fear that terror attacks leave on tourists, sometimes creating such an impression that tourists change travel plans as a result. Although there are many studies on destination image, risk perception, and decision-making, very few focus specifically on the millennial generation. Because millennials are changing the travel and tourism scene - as they now make up the largest percentage of the population \u2014 it is important for stakeholders in the tourism industry and DMOs to understand this shift and the implications that come with these changes. This study provides a qualitative analysis of millennials' views, attitudes, and beliefs regarding terror impacted tourist destinations. Specifically, it will explore how millennials develop their destination images, if millennials view international travel to be risky, and if millennials are willing to travel to terror impacted tourist destinations. Using focus group methodology, this study gathered data from students from a number of disciplines, genders, and travel experience, in order to understand the themes listed above. Analysis of the findings and implications for officials and DMOs follow, as well as a conclusion including limitations and recommendations for future studies.
ContributorsBacon, Laura Elizabeth (Author) / Buzinde, Christine (Thesis director) / Nyaupane, Gyan (Committee member) / Department of Management and Entrepreneurship (Contributor) / W. P. Carey School of Business (Contributor) / College of Public Service and Community Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05