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Description
Geographically Weighted Regression (GWR) has been broadly used in various fields to
model spatially non-stationary relationships. Classic GWR is considered as a single-scale model that is based on one bandwidth parameter which controls the amount of distance-decay in weighting neighboring data around each location. The single bandwidth in GWR assumes that processes (relationships between the response variable and the predictor variables) all operate at the same scale. However, this posits a limitation in modeling potentially multi-scale processes which are more often seen in the real world. For example, the measured ambient temperature of a location is affected by the built environment, regional weather and global warming, all of which operate at different scales. A recent advancement to GWR termed Multiscale GWR (MGWR) removes the single bandwidth assumption and allows the bandwidths for each covariate to vary. This results in each parameter surface being allowed to have a different degree of spatial variation, reflecting variation across covariate-specific processes. In this way, MGWR has the capability to differentiate local, regional and global processes by using varying bandwidths for covariates. Additionally, bandwidths in MGWR become explicit indicators of the scale at various processes operate. The proposed dissertation covers three perspectives centering on MGWR: Computation; Inference; and Application. The first component focuses on addressing computational issues in MGWR to allow MGWR models to be calibrated more efficiently and to be applied on large datasets. The second component aims to statistically differentiate the spatial scales at which different processes operate by quantifying the uncertainty associated with each bandwidth obtained from MGWR. In the third component, an empirical study will be conducted to model the changing relationships between county-level socio-economic factors and voter preferences in the 2008-2016 United States presidential elections using MGWR.
model spatially non-stationary relationships. Classic GWR is considered as a single-scale model that is based on one bandwidth parameter which controls the amount of distance-decay in weighting neighboring data around each location. The single bandwidth in GWR assumes that processes (relationships between the response variable and the predictor variables) all operate at the same scale. However, this posits a limitation in modeling potentially multi-scale processes which are more often seen in the real world. For example, the measured ambient temperature of a location is affected by the built environment, regional weather and global warming, all of which operate at different scales. A recent advancement to GWR termed Multiscale GWR (MGWR) removes the single bandwidth assumption and allows the bandwidths for each covariate to vary. This results in each parameter surface being allowed to have a different degree of spatial variation, reflecting variation across covariate-specific processes. In this way, MGWR has the capability to differentiate local, regional and global processes by using varying bandwidths for covariates. Additionally, bandwidths in MGWR become explicit indicators of the scale at various processes operate. The proposed dissertation covers three perspectives centering on MGWR: Computation; Inference; and Application. The first component focuses on addressing computational issues in MGWR to allow MGWR models to be calibrated more efficiently and to be applied on large datasets. The second component aims to statistically differentiate the spatial scales at which different processes operate by quantifying the uncertainty associated with each bandwidth obtained from MGWR. In the third component, an empirical study will be conducted to model the changing relationships between county-level socio-economic factors and voter preferences in the 2008-2016 United States presidential elections using MGWR.
ContributorsLi, Ziqi (Author) / Fotheringham, A. Stewart (Thesis advisor) / Goodchild, Michael F. (Committee member) / Li, Wenwen (Committee member) / Arizona State University (Publisher)
Created2020
Description
In the recent times, traffic congestion and motor accidents have been a major problem for transportation in major cities. Intelligent Transportation Systems has the potential to be an effective solution in order to tackle this issue. Connected Autonomous Vehicles can cooperate at intersections, ramp merging, lane change and other conflicting scenarios in order to resolve the conflicts and avoid collisions with other vehicles. A lot of works has been proposed for specific scenarios such as intersections, ramp merging or lane change which partially solve the conflict resolution problem. Also, one of the major issues in autonomous decision making - deadlocks have not been considered in some of the works. The existing works either do not consider deadlocks or lack a safety proof. This thesis proposes a cooperative driving solution that provides a complete navigation, conflict resolution and deadlock resolution for connected autonomous vehicles. A graph-based model is used to resolve the deadlocks between vehicles and the responsibility sensitive safety (RSS) rules have been used in order to ensure safety of the autonomous vehicles during conflict detection and resolution. This algorithm provides a complete navigation solution for an autonomous vehicle from its source to destination. The algorithm ensures that accidents do not occur even in the worst-case scenario and the decision making is deadlock free.
ContributorsAllamsetti, Harshith (Author) / Shrivastava, Aviral (Thesis advisor) / Sen, Arunabha (Committee member) / Ren, Fengbo (Committee member) / Arizona State University (Publisher)
Created2020
Description
The discovery that mechanical forces regulate microbial virulence, stress responses and gene expression was made using log phase cultures of Salmonella Typhimurium (S. Typhimurium) grown under low fluid shear (LFS) conditions relevant to those encountered in the intestine. However, there has been limited characterization of LFS on other growth phases. To advance the growth-phase dependent understanding of the effect of LFS on S. Typhimurium pathogenicity, this dissertation characterized the effect of LFS on the transcriptomic and phenotypic responses in both stationary and lag phase cultures. In response to LFS, stationary phase cultures exhibited alterations in gene expression associated with metabolism, transport, secretion and stress responses (acid, bile salts, oxidative, and thermal stressors), motility, and colonization of intestinal epithelium (adherence, invasion and intracellular survival). Many of these characteristics are known to be regulated by the stationary phase general stress response regulator, RNA polymerase sigma factor S (RpoS), when S. Typhimurium is grown under conventional conditions. Surprisingly, the stationary phase phenotypic LFS stress response to acid and bile salts, colonization of human intestinal epithelial cells, and swimming motility was not dependent on RpoS. Lag phase cultures exhibited intriguing differences in their LFS regulated transcriptomic and phenotypic profiles as compared to stationary phase cultures, including LFS-dependent regulation of gene expression, adherence to intestinal epithelial cells, and high thermal stress. Furthermore, the addition of cell-free conditioned supernatants derived from either stationary phase LFS or Control cultures modulated the gene expression of lag phase cultures in a manner that differed from either growth phase, however, these supernatants did not modulate the phenotypic responses of lag phase cultures. Collectively, these results demonstrated that S. Typhimurium can sense and respond to LFS as early as lag phase, albeit in a limited fashion, and that the lag phase transcriptomic and phenotypic responses differ from those in stationary phase, which hold important implications for the lifecycle of this pathogen during the infection process.
ContributorsFranco, Karla Paola (Author) / Nikerson, Cheryl A (Thesis advisor) / Bean, Heather D (Committee member) / Stout, Valerie (Committee member) / Ott, C Mark (Committee member) / Barrila, Jennifer (Committee member) / Arizona State University (Publisher)
Created2020
Description
Power systems are undergoing a significant transformation as a result of the retirements of conventional coal-fired generation units and the increasing integration of converter interfaced renewable resources. The instantaneous renewable generation penetration as a percentage of the load served in megawatt (MW), in some areas of the United States (U.S.) sometimes approaches over 50 percent. These changes have introduced new challenges for reliability studies considering the two functional reliability aspects, i.e., adequacy and the dynamic security or operating reliability.
Adequacy assessment becomes more complex due to the variability introduced by renewable energy generation. The traditionally used reserve margin only considers projected peak demand and would be inadequate since it does not consider an evaluation of off-peak conditions that could also be critical due to the variable renewable generation. Therefore, in order to address the impact of variable renewable generation, a probabilistic evaluation that studies all hours of a year based on statistical characteristics is a necessity to identify the adequacy risks. On the other hand, the system dynamic behavior is also changing. Converter interfaced generation resources have different dynamic characteristics from the conventional synchronous units and inherently do not participate in grid regulation functions such as frequency control and voltage control that are vital to maintaining operating reliability. In order to evaluate these evolving grid characteristics, comprehensive reliability evaluation approaches that consider system stochasticity and evaluate both adequacy and dynamic security are important to identify potential system risks in this transforming environment.
Adequacy assessment becomes more complex due to the variability introduced by renewable energy generation. The traditionally used reserve margin only considers projected peak demand and would be inadequate since it does not consider an evaluation of off-peak conditions that could also be critical due to the variable renewable generation. Therefore, in order to address the impact of variable renewable generation, a probabilistic evaluation that studies all hours of a year based on statistical characteristics is a necessity to identify the adequacy risks. On the other hand, the system dynamic behavior is also changing. Converter interfaced generation resources have different dynamic characteristics from the conventional synchronous units and inherently do not participate in grid regulation functions such as frequency control and voltage control that are vital to maintaining operating reliability. In order to evaluate these evolving grid characteristics, comprehensive reliability evaluation approaches that consider system stochasticity and evaluate both adequacy and dynamic security are important to identify potential system risks in this transforming environment.
ContributorsWang, Yingying (Author) / Vittal, Vijay (Thesis advisor) / Khorsand, Mojdeh (Thesis advisor) / Heydt, Gerald (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2020
Description
The Adequate Intake (AI) level for total fiber for adults is 14 grams per 1,000 kilocalories per day; however, only 12.9% of Americans met their total fiber needs according to the 2015-2016 National Health and Nutrition Examination Survey (NHANES). A lower frequency of home-cooked meals and a higher frequency of restaurant meals have been cited as a possible explanation for the low dietary fiber intake among Americans, and according to the Social-Ecological Model, the retail food environment can influence our food choices such as the choice to eat at home or eat out. The objective of this study is to examine the relationship between a dynamic measurement of exposure to the retail food environment and fiber intake (total fiber, soluble fiber, insoluble fiber, and pectin). This is a secondary analysis of data from the Community of Mine study, a cross-sectional study of 602 adults residing in San Diego County, California. Dynamic exposure to the retail food environment was assessed using Global Positioning Systems (GPS) data collected by the Qstarz GPS device worn by each participant. Fiber intake was assessed using two 24-hour dietary recalls. Multivariate regression analysis was used to assess correlations. Descriptive results showed no significant differences in dynamic exposure to the retail food environment by sex, Hispanic ethnicity, and income. There were significant differences in fiber intake by sex and ethnicity. The results of the multivariate regression analysis suggest that exposure to the retail food environment is not associated with fiber intake among a subset of American adults.
ContributorsHarb, Amanda A (Author) / Sears, Dorothy (Thesis advisor) / Alexon, Christy (Committee member) / Jankowska, Marta (Committee member) / Ohri-Vachaspati, Punam (Committee member) / Arizona State University (Publisher)
Created2020
Description
The present study aims to gain deeper insights into language attitudes in the educational context while contributing to the emerging field of advanced mixed, second language and heritage language (HL) courses. Considering that the majority of heritage language learners (HLLs) and second language learners (L2s) in the United States (US) are enrolled in mixed classrooms (Beaudrie, 2012; Carreira, 2016a, 2016b), the study of language attitudes regarding monolingual varieties, bilingual varieties, and L2 varieties is crucial to inform pedagogical best practices that serve both types of learners. Additionally, by analyzing the language attitudes of both types of students toward these three Spanish language varieties, this study demonstrates the importance of incorporating linguistic variation into the classroom to address the linguistic hierarchies that exist in such a context. Thus, the results are relevant to the fields of sociolinguistics, L2 and HL pedagogy.
The study employs matched-guise tasks at two points during the semester, as well as end-term semi-structured interviews. As different linguistic components of a language trigger different attitudes, the findings show that native-like phonetic and phonological features of Spanish speakers afford positive attitudes, as do a formal lexicon and academic register. However, morphosyntactic features do not have any effect on forming an individual’s language attitudes.
To illustrate, the results of the matched-guise tasks show that native and HL varieties were generally evaluated positively, while L2 varieties were evaluated negatively. Interviews revealed native-like accent and pronunciation as the detrimental cause of negative attitudes toward the L2 variety. In contrast to the phonetic/phonological evaluations made by participants, both HLLs and L2s did agree that L2s speak a “proper” and “professional” Spanish. Furthermore, heritage Spanish was described as the “least formal” and “incorrect” Spanish variety in comparison to the L2 variety due to dominant stereotypes and ideologies and the incorporation of lexical characteristics of US Spanish.
Based on these findings, this study has the potential to make an invaluable contribution to understanding how language attitudes and instructional practices in the classroom context intersect with a social justice movement to improve mixed courses in a social, critical, and conscious way.
The study employs matched-guise tasks at two points during the semester, as well as end-term semi-structured interviews. As different linguistic components of a language trigger different attitudes, the findings show that native-like phonetic and phonological features of Spanish speakers afford positive attitudes, as do a formal lexicon and academic register. However, morphosyntactic features do not have any effect on forming an individual’s language attitudes.
To illustrate, the results of the matched-guise tasks show that native and HL varieties were generally evaluated positively, while L2 varieties were evaluated negatively. Interviews revealed native-like accent and pronunciation as the detrimental cause of negative attitudes toward the L2 variety. In contrast to the phonetic/phonological evaluations made by participants, both HLLs and L2s did agree that L2s speak a “proper” and “professional” Spanish. Furthermore, heritage Spanish was described as the “least formal” and “incorrect” Spanish variety in comparison to the L2 variety due to dominant stereotypes and ideologies and the incorporation of lexical characteristics of US Spanish.
Based on these findings, this study has the potential to make an invaluable contribution to understanding how language attitudes and instructional practices in the classroom context intersect with a social justice movement to improve mixed courses in a social, critical, and conscious way.
ContributorsVana, Rosti Frank (Author) / Beaudrie, Sara (Thesis advisor) / Cerron-Palomino, Alvaro (Thesis advisor) / Gradoville, Michael (Committee member) / Carreira, Maria (Committee member) / Arizona State University (Publisher)
Created2020
Description
This thesis introduces a new robotic leg design with three degrees of freedom that
can be adapted for both bipedal and quadrupedal locomotive systems, and serves as
a blueprint for designers attempting to create low cost robot legs capable of balancing
and walking. Currently, bipedal leg designs are mostly rigid and have not strongly
taken into account the advantages/disadvantages of using an active ankle, as opposed
to a passive ankle, for balancing. This design uses low-cost compliant materials, but
the materials used are thick enough to mimic rigid properties under low stresses, so
this paper will treat the links as rigid materials. A new leg design has been created
that contains three degrees of freedom that can be adapted to contain either a passive
ankle using springs, or an actively controlled ankle using an additional actuator. This
thesis largely aims to focus on the ankle and foot design of the robot and the torque
and speed requirements of the design for motor selection. The dynamics of the system,
including height, foot width, weight, and resistances will be analyzed to determine
how to improve design performance. Model-based control techniques will be used to
control the angle of the leg for balancing. In doing so, it will also be shown that it
is possible to implement model-based control techniques on robots made of laminate
materials.
can be adapted for both bipedal and quadrupedal locomotive systems, and serves as
a blueprint for designers attempting to create low cost robot legs capable of balancing
and walking. Currently, bipedal leg designs are mostly rigid and have not strongly
taken into account the advantages/disadvantages of using an active ankle, as opposed
to a passive ankle, for balancing. This design uses low-cost compliant materials, but
the materials used are thick enough to mimic rigid properties under low stresses, so
this paper will treat the links as rigid materials. A new leg design has been created
that contains three degrees of freedom that can be adapted to contain either a passive
ankle using springs, or an actively controlled ankle using an additional actuator. This
thesis largely aims to focus on the ankle and foot design of the robot and the torque
and speed requirements of the design for motor selection. The dynamics of the system,
including height, foot width, weight, and resistances will be analyzed to determine
how to improve design performance. Model-based control techniques will be used to
control the angle of the leg for balancing. In doing so, it will also be shown that it
is possible to implement model-based control techniques on robots made of laminate
materials.
ContributorsShafa, Taha A (Author) / Aukes, Daniel M (Thesis advisor) / Rogers, Bradley (Committee member) / Zhang, Wenlong (Committee member) / Arizona State University (Publisher)
Created2020
Description
My dissertation combines the notion of residential sorting from Tiebout (1956) with Grossman’s (1972) concept of a health production function to develop a new empirical framework for investigating what individuals’ residential location choices reveal about their valuation of amenities, the welfare effects of climate change, the forces underlying environmental justice, and the value of a statistical life. Location
choices are affected by age, health, and financial constraints, and by exposure to local amenities that affect people’s health and longevity. Chapter 1 previews how I formalize this idea and investigate its empirical implications in three interrelated essays. Chapter 2 investigates interactions between health, the environment, and income. Seniors tend to move at higher rates after being diagnosed with new chronic medical conditions. While seniors generally tend to move to locations with less polluted air, those who have been diagnosed with respiratory conditions move to relatively more polluted locations. This counterintuitive pattern is reconciled by documenting that new diagnoses bring about increases in medical expenditures, thereby limiting disposable income that can be spent on housing. Relatively cheaper places tend to be more polluted, and higher exposure to pollution leaves seniors more vulnerable to future health shocks. In Chapter 3, I combine information about housing prices with estimates of location-specific effects on mortality to estimate the Value of a Statistical Life (VSL) for seniors - one of the most important statistics used to evaluate policies affecting mortality. Since local amenities correlate with causal mortality effects, but also provide utility independently, the difficulty in controlling for local amenities implies that my VSL estimates are best interpreted as bounds. Chapter 4 builds a new structural framework for evaluating spatially heterogeneous changes to local amenities. I estimate a dynamic model of location choice with a sample of 5.5 million seniors from 2001-2013. Their average annual willingness-to-pay to avoid future climate change in the United States under a “business as usual” scenario ranges from $962 for older, sicker groups who are more vulnerable to climate change’s negative effects on health to -$1,894 for younger, healthier groups, who value warmer winters and are relatively resilient.
choices are affected by age, health, and financial constraints, and by exposure to local amenities that affect people’s health and longevity. Chapter 1 previews how I formalize this idea and investigate its empirical implications in three interrelated essays. Chapter 2 investigates interactions between health, the environment, and income. Seniors tend to move at higher rates after being diagnosed with new chronic medical conditions. While seniors generally tend to move to locations with less polluted air, those who have been diagnosed with respiratory conditions move to relatively more polluted locations. This counterintuitive pattern is reconciled by documenting that new diagnoses bring about increases in medical expenditures, thereby limiting disposable income that can be spent on housing. Relatively cheaper places tend to be more polluted, and higher exposure to pollution leaves seniors more vulnerable to future health shocks. In Chapter 3, I combine information about housing prices with estimates of location-specific effects on mortality to estimate the Value of a Statistical Life (VSL) for seniors - one of the most important statistics used to evaluate policies affecting mortality. Since local amenities correlate with causal mortality effects, but also provide utility independently, the difficulty in controlling for local amenities implies that my VSL estimates are best interpreted as bounds. Chapter 4 builds a new structural framework for evaluating spatially heterogeneous changes to local amenities. I estimate a dynamic model of location choice with a sample of 5.5 million seniors from 2001-2013. Their average annual willingness-to-pay to avoid future climate change in the United States under a “business as usual” scenario ranges from $962 for older, sicker groups who are more vulnerable to climate change’s negative effects on health to -$1,894 for younger, healthier groups, who value warmer winters and are relatively resilient.
ContributorsMathes, Sophie (Author) / Kuminoff, Nicolai V. (Thesis advisor) / Murphy, Alvin D (Thesis advisor) / Bishop, Kelly C. (Committee member) / Ketcham, Jonathan (Committee member) / Bick, Alexander (Committee member) / Arizona State University (Publisher)
Created2020
Description
ABSTRACT
The cold and the flu are two of the most prevalent diseases in the world. Many over the counter (OTC) medications have been created to combat the symptoms of these illnesses. Some medications take a holistic approach by claiming to alleviate a wide range of symptoms, while others target a specific symptom. As these medications become more ubiquitous within the United State of America (USA), consumers form associations and mental models about the cold/flu field. The goal of Study 1 was to build a Pathfinder network based on the associations consumers make between cold/flu symptoms and medications. 100 participants, 18 years or older, fluent in English, and residing in the USA, completed a survey about the relatedness of cold/flu symptoms to OTC medications. They rated the relatedness on a scale of 1 (highly unrelated) to 7 (highly related) and those rankings were used to build a Pathfinder network that represented the average of those associations. Study 2 was conducted to validate the Pathfinder network. A different set of 90 participants with the same restrictions as those in Study 1 completed a matching associations test. They were prompted to match symptoms and medications they associated closely with each other. Results showered a significant negative correlation between the geodetic distance (the number of links between objects in the Pathfinder network) separating symptoms and medications and frequency of pairing symptoms with medication. This provides evidence of the validity of the Pathfinder network. It was also seen that, higher the relatedness rating between symptoms and medications in Study 1, higher the frequency of pairing symptom to medication in Study 2, and the more directly linked those symptoms and medications were in the Pathfinder network. This network can inform pharmaceutical companies about which symptoms they most closely associate with, who their competitors are, what symptoms they can dominate, and how to market their medications more effectively.
The cold and the flu are two of the most prevalent diseases in the world. Many over the counter (OTC) medications have been created to combat the symptoms of these illnesses. Some medications take a holistic approach by claiming to alleviate a wide range of symptoms, while others target a specific symptom. As these medications become more ubiquitous within the United State of America (USA), consumers form associations and mental models about the cold/flu field. The goal of Study 1 was to build a Pathfinder network based on the associations consumers make between cold/flu symptoms and medications. 100 participants, 18 years or older, fluent in English, and residing in the USA, completed a survey about the relatedness of cold/flu symptoms to OTC medications. They rated the relatedness on a scale of 1 (highly unrelated) to 7 (highly related) and those rankings were used to build a Pathfinder network that represented the average of those associations. Study 2 was conducted to validate the Pathfinder network. A different set of 90 participants with the same restrictions as those in Study 1 completed a matching associations test. They were prompted to match symptoms and medications they associated closely with each other. Results showered a significant negative correlation between the geodetic distance (the number of links between objects in the Pathfinder network) separating symptoms and medications and frequency of pairing symptoms with medication. This provides evidence of the validity of the Pathfinder network. It was also seen that, higher the relatedness rating between symptoms and medications in Study 1, higher the frequency of pairing symptom to medication in Study 2, and the more directly linked those symptoms and medications were in the Pathfinder network. This network can inform pharmaceutical companies about which symptoms they most closely associate with, who their competitors are, what symptoms they can dominate, and how to market their medications more effectively.
ContributorsTendolkar, Tanvi Gopal (Author) / Branaghan, Russell (Thesis advisor) / Chiou, Erin (Committee member) / Craig, Scotty (Committee member) / Arizona State University (Publisher)
Created2020
Description
This thesis focuses on serial crystallography studies with X-ray free electron lasers
(XFEL) with a special emphasis on data analysis to investigate important processes
in bioenergy conversion and medicinal applications.
First, the work on photosynthesis focuses on time-resolved femtosecond crystallography
studies of Photosystem II (PSII). The structural-dynamic studies of the water
splitting reaction centering on PSII is a current hot topic of interest in the field, the
goal of which is to capture snapshots of the structural changes during the Kok cycle.
This thesis presents results from time-resolved serial femtosecond (fs) crystallography
experiments (TR-SFX) where data sets are collected at room temperature from a
stream of crystals that intersect with the ultrashort femtosecond X-ray pulses at an
XFEL with the goal to obtain structural information from the transient state (S4)
state of the cycle where the O=O bond is formed, and oxygen is released. The most
current techniques available in SFX/TR-SFX to handle hundreds of millions of raw
diffraction patterns are discussed, including selection of the best diffraction patterns,
allowing for their indexing and further data processing. The results include two 4.0 Å
resolution structures of the ground S1 state and triple excited S4 transient state.
Second, this thesis reports on the first international XFEL user experiments in
South Korea at the Pohang Accelerator Laboratory (PAL-XFEL). The usability of this
new XFEL in a proof-of-principle experiment for the study of microcrystals of human
taspase1 (an important cancer target) by SFX has been tested. The descriptions of
experiments and discussions of specific data evaluation challenges of this project in
light of the taspase1 crystals’ high anisotropy, which limited the resolution to 4.5 Å,
are included in this report
In summary, this thesis examines current techniques that are available in the
SFX/TR-SFX domain to study crystal structures from microcrystals damage-free,
with the future potential of making movies of biological processes.
(XFEL) with a special emphasis on data analysis to investigate important processes
in bioenergy conversion and medicinal applications.
First, the work on photosynthesis focuses on time-resolved femtosecond crystallography
studies of Photosystem II (PSII). The structural-dynamic studies of the water
splitting reaction centering on PSII is a current hot topic of interest in the field, the
goal of which is to capture snapshots of the structural changes during the Kok cycle.
This thesis presents results from time-resolved serial femtosecond (fs) crystallography
experiments (TR-SFX) where data sets are collected at room temperature from a
stream of crystals that intersect with the ultrashort femtosecond X-ray pulses at an
XFEL with the goal to obtain structural information from the transient state (S4)
state of the cycle where the O=O bond is formed, and oxygen is released. The most
current techniques available in SFX/TR-SFX to handle hundreds of millions of raw
diffraction patterns are discussed, including selection of the best diffraction patterns,
allowing for their indexing and further data processing. The results include two 4.0 Å
resolution structures of the ground S1 state and triple excited S4 transient state.
Second, this thesis reports on the first international XFEL user experiments in
South Korea at the Pohang Accelerator Laboratory (PAL-XFEL). The usability of this
new XFEL in a proof-of-principle experiment for the study of microcrystals of human
taspase1 (an important cancer target) by SFX has been tested. The descriptions of
experiments and discussions of specific data evaluation challenges of this project in
light of the taspase1 crystals’ high anisotropy, which limited the resolution to 4.5 Å,
are included in this report
In summary, this thesis examines current techniques that are available in the
SFX/TR-SFX domain to study crystal structures from microcrystals damage-free,
with the future potential of making movies of biological processes.
ContributorsKetawala, Gihan Kaushyal (Author) / Fromme, Petra (Thesis advisor) / Liu, Wei (Committee member) / Kirian, Richard (Committee member) / Arizona State University (Publisher)
Created2020