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Description
Glycosaminoglycans (GAGs) are a class of complex biomolecules comprised of linear, sulfated polysaccharides whose presence on cell surfaces and in the extracellular matrix involve them in many physiological phenomena as well as in interactions with pathogenic microbes. Decorin binding protein A (DBPA), a Borrelia surface lipoprotein involved in the infectivity of Lyme disease, is responsible for binding GAGs found on decorin, a small proteoglycan present in the extracellular matrix. Different DBPA strains have notable sequence heterogeneity that results in varying levels of GAG-binding affinity. In this dissertation, the structures and GAG-binding mechanisms for three strains of DBPA (B31 and N40 DBPAs from B. burgdorferi and PBr DBPA from B. garinii) are studied to determine why each strain has a different affinity for GAGs. These three strains have similar topologies consisting of five α-helices held together by a hydrophobic core as well as two long flexible segments: a linker between helices one and two and a C-terminal tail. This structural arrangement facilitates the formation of a basic pocket below the flexible linker which is the primary GAG-binding epitope. However, this GAG-binding site can be occluded by the flexible linker, which makes the linker a negative regulator of GAG-binding. ITC and NMR titrations provide KD values that show PBr DBPA binds GAGs with higher affinity than B31 and N40 DBPAs, while N40 binds with the lowest affinity of the three. Work in this thesis demonstrates that much of the discrepancies seen in GAG affinities of the three DBPAs can be explained by the amino acid composition and conformation of the linker. Mutagenesis studies show that B31 DBPA overcomes the pocket obstruction with the BXBB motif in its linker while PBr DBPA has a retracted linker that exposes the basic pocket as well as a secondary GAG-binding site. N40 DBPA, however, does not have any evolutionary modifications to its structure to enhance GAG binding which explains its lower affinity for GAGs. GMSA and ELISA assays, along with NMR PRE experiments, confirm that structural changes in the linker do affect GAG-binding and, as a result, the linker is responsible for regulating GAG affinity.
ContributorsMorgan, Ashli M (Author) / Wang, Xu (Thesis advisor) / Allen, James (Committee member) / Yarger, Jeffery (Committee member) / Arizona State University (Publisher)
Created2015
Description
Nanoparticle suspensions, popularly termed “nanofluids,” have been extensively investigated for their thermal and radiative properties. Such work has generated great controversy, although it is arguably accepted today that the presence of nanoparticles rarely leads to useful enhancements in either thermal conductivity or convective heat transfer. On the other hand, there are still examples of unanticipated enhancements to some properties, such as the reported specific heat of molten salt-based nanofluids and the critical heat flux. Another largely overlooked example is the apparent effect of nanoparticles on the effective latent heat of vaporization (hfg) of aqueous nanofluids. A previous study focused on molecular dynamics (MD) modeling supplemented with limited experimental data to suggest that hfg increases with increasing nanoparticle concentration.
Here, this research extends that exploratory work in an effort to determine if hfg of aqueous nanofluids can be manipulated, i.e., increased or decreased, by the addition of graphite or silver nanoparticles. Our results to date indicate that hfg can be substantially impacted, by up to ± 30% depending on the type of nanoparticle. Moreover, this dissertation reports further experiments with changing surface area based on volume fraction (0.005% to 2%) and various nanoparticle sizes to investigate the mechanisms for hfg modification in aqueous graphite and silver nanofluids. This research also investigates thermophysical properties, i.e., density and surface tension in aqueous nanofluids to support the experimental results of hfg based on the Clausius - Clapeyron equation. This theoretical investigation agrees well with the experimental results. Furthermore, this research investigates the hfg change of aqueous nanofluids with nanoscale studies in terms of melting of silver nanoparticles and hydrophobic interactions of graphite nanofluid. As a result, the entropy change due to those mechanisms could be a main cause of the changes of hfg in silver and graphite nanofluids.
Finally, applying the latent heat results of graphite and silver nanofluids to an actual solar thermal system to identify enhanced performance with a Rankine cycle is suggested to show that the tunable latent heat of vaporization in nanofluilds could be beneficial for real-world solar thermal applications with improved efficiency.
Here, this research extends that exploratory work in an effort to determine if hfg of aqueous nanofluids can be manipulated, i.e., increased or decreased, by the addition of graphite or silver nanoparticles. Our results to date indicate that hfg can be substantially impacted, by up to ± 30% depending on the type of nanoparticle. Moreover, this dissertation reports further experiments with changing surface area based on volume fraction (0.005% to 2%) and various nanoparticle sizes to investigate the mechanisms for hfg modification in aqueous graphite and silver nanofluids. This research also investigates thermophysical properties, i.e., density and surface tension in aqueous nanofluids to support the experimental results of hfg based on the Clausius - Clapeyron equation. This theoretical investigation agrees well with the experimental results. Furthermore, this research investigates the hfg change of aqueous nanofluids with nanoscale studies in terms of melting of silver nanoparticles and hydrophobic interactions of graphite nanofluid. As a result, the entropy change due to those mechanisms could be a main cause of the changes of hfg in silver and graphite nanofluids.
Finally, applying the latent heat results of graphite and silver nanofluids to an actual solar thermal system to identify enhanced performance with a Rankine cycle is suggested to show that the tunable latent heat of vaporization in nanofluilds could be beneficial for real-world solar thermal applications with improved efficiency.
ContributorsLee, Soochan (Author) / Phelan, Patrick E (Thesis advisor) / Wu, Carole-Jean (Thesis advisor) / Wang, Robert (Committee member) / Wang, Liping (Committee member) / Taylor, Robert A. (Committee member) / Prasher, Ravi (Committee member) / Arizona State University (Publisher)
Created2015
Description
Cosmology, carrying imprints from the entire history of the universe, has emerged as a precise observational science over the past 30 years. It can probe physics beyond the Standard Model at energy scales much higher than the weak scale. This thesis reports on some important probes of beyond standard model physics derived in a cosmological setting - (I) It is shown that primordial gravitational waves left over from inflation carry unique detectable CMB signatures for neutrino masses, axions and any other relativistic species that may have been present. (II) Higgs Inflation, the most popular and compelling inflation model with a higgs boson is studied next and it is shown that quantum effects have so far been incorrectly incorporated. A spurious gauge ambiguity arising from quantum effects enters the canonical prediction for observables in Higgs Inflation that must be addressed. (III) A new novel mechanism for generating the observed baryon asymmetry of the universe via decaying gravitinos is proposed. If the Supersymmetry (SUSY) breaking scale is high, then in the presence of R-parity violation, gravitinos can successfully reproduce the baryon asymmetry and evade all low energy constraints. (IV) The final chapter reports on a new completely general analysis of simplified models used in direct detection of dark matter. This is useful to explore what high energy physics constraints can be obtained from direct detection experiments.
ContributorsSabharwal, Subir (Author) / Krauss, Lawrence M (Thesis advisor) / Vachaspati, Tanmay (Thesis advisor) / Mauskopf, Philip D (Committee member) / Lunardini, Cecilia (Committee member) / Arizona State University (Publisher)
Created2015
Description
Engineering education can provide students with the tools to address complex, multidisciplinary grand challenge problems in sustainable and global contexts. However, engineering education faces several challenges, including low diversity percentages, high attrition rates, and the need to better engage and prepare students for the role of a modern engineer. These challenges can be addressed by integrating sustainability grand challenges into engineering curriculum.
Two main strategies have emerged for integrating sustainability grand challenges. In the stand-alone course method, engineering programs establish one or two distinct courses that address sustainability grand challenges in depth. In the module method, engineering programs integrate sustainability grand challenges throughout existing courses. Neither method has been assessed in the literature.
This thesis aimed to develop sustainability modules, to create methods for evaluating the modules’ effectiveness on student cognitive and affective outcomes, to create methods for evaluating students’ cumulative sustainability knowledge, and to evaluate the stand-alone course method to integrate sustainability grand challenges into engineering curricula via active and experiential learning.
The Sustainable Metrics Module for teaching sustainability concepts and engaging and motivating diverse sets of students revealed that the activity portion of the module had the greatest impact on learning outcome retention.
The Game Design Module addressed methods for assessing student mastery of course content with student-developed games indicated that using board game design improved student performance and increased student satisfaction.
Evaluation of senior design capstone projects via novel comprehensive rubric to assess sustainability learned over students’ curriculum revealed that students’ performance is primarily driven by their instructor’s expectations. The rubric provided a universal tool for assessing students’ sustainability knowledge and could also be applied to sustainability-focused projects.
With this in mind, engineering educators should pursue modules that connect sustainability grand challenges to engineering concepts, because student performance improves and students report higher satisfaction. Instructors should utilize pedagogies that engage diverse students and impact concept retention, such as active and experiential learning. When evaluating the impact of sustainability in the curriculum, innovative assessment methods should be employed to understand student mastery and application of course concepts and the impacts that topics and experiences have on student satisfaction.
Two main strategies have emerged for integrating sustainability grand challenges. In the stand-alone course method, engineering programs establish one or two distinct courses that address sustainability grand challenges in depth. In the module method, engineering programs integrate sustainability grand challenges throughout existing courses. Neither method has been assessed in the literature.
This thesis aimed to develop sustainability modules, to create methods for evaluating the modules’ effectiveness on student cognitive and affective outcomes, to create methods for evaluating students’ cumulative sustainability knowledge, and to evaluate the stand-alone course method to integrate sustainability grand challenges into engineering curricula via active and experiential learning.
The Sustainable Metrics Module for teaching sustainability concepts and engaging and motivating diverse sets of students revealed that the activity portion of the module had the greatest impact on learning outcome retention.
The Game Design Module addressed methods for assessing student mastery of course content with student-developed games indicated that using board game design improved student performance and increased student satisfaction.
Evaluation of senior design capstone projects via novel comprehensive rubric to assess sustainability learned over students’ curriculum revealed that students’ performance is primarily driven by their instructor’s expectations. The rubric provided a universal tool for assessing students’ sustainability knowledge and could also be applied to sustainability-focused projects.
With this in mind, engineering educators should pursue modules that connect sustainability grand challenges to engineering concepts, because student performance improves and students report higher satisfaction. Instructors should utilize pedagogies that engage diverse students and impact concept retention, such as active and experiential learning. When evaluating the impact of sustainability in the curriculum, innovative assessment methods should be employed to understand student mastery and application of course concepts and the impacts that topics and experiences have on student satisfaction.
ContributorsAntaya, Claire Louise (Author) / Landis, Amy E. (Thesis advisor) / Parrish, Kristen (Thesis advisor) / Bilec, Melissa M (Committee member) / Besterfield-Sacre, Mary E (Committee member) / Allenby, Braden R. (Committee member) / Arizona State University (Publisher)
Created2015
Description
This study examines the effects of providing persuasive writing and reading comprehension strategy training on source-based essay writing. Strategy training was administered through the use of the Writing Pal and the Interactive Strategy Trainer for Active Reading and Thinking (iSTART). The impact of both individual (writing or reading) and blended strategy training on source-based writing was investigated. A total of 261 participants completed the study; after removing incomplete and second language participants the source-based writing and system performance was assessed for 175 participants (n no instruction = 48, n iSTART =41, n Writing Pal =41, n blended =45).
Results indicated that participants who received blended strategy training produced higher quality source-based essays than participants who received only reading comprehension, writing strategy training, or no training. Furthermore, participants who received only reading comprehension or writing strategy training did not produce higher quality source-based essays than participants in the no-training control group. Time on task was investigated as a potential explanation for the results. Neither total time on task nor practice time were predictive of group differences on source-based essay scores. Analyses further suggested that the impact of strategy training does not differ as a function of prior abilities; however, training does seem to impact the relation between prior abilities and source-based essay scores. Specifically, prior writing ability was unrelated to performance for those who received writing training (i.e., Writing Pal and blended conditions), and prior reading ability was unrelated to performance for those received the full dosage of iSTART training. Overall, the findings suggest that when taught in conjunction with one another, reading comprehension and writing strategy training transfers to source-based writing, providing a positive impact on score. Potential changes to the Writing Pal and iSTART to more closely align training with source-based writing are discussed as methods of further increasing the impact of training on source-based writing.
Results indicated that participants who received blended strategy training produced higher quality source-based essays than participants who received only reading comprehension, writing strategy training, or no training. Furthermore, participants who received only reading comprehension or writing strategy training did not produce higher quality source-based essays than participants in the no-training control group. Time on task was investigated as a potential explanation for the results. Neither total time on task nor practice time were predictive of group differences on source-based essay scores. Analyses further suggested that the impact of strategy training does not differ as a function of prior abilities; however, training does seem to impact the relation between prior abilities and source-based essay scores. Specifically, prior writing ability was unrelated to performance for those who received writing training (i.e., Writing Pal and blended conditions), and prior reading ability was unrelated to performance for those received the full dosage of iSTART training. Overall, the findings suggest that when taught in conjunction with one another, reading comprehension and writing strategy training transfers to source-based writing, providing a positive impact on score. Potential changes to the Writing Pal and iSTART to more closely align training with source-based writing are discussed as methods of further increasing the impact of training on source-based writing.
ContributorsWeston Jennifer L (Author) / McNamara, Danielle S. (Thesis advisor) / Connor, Carol M (Committee member) / Glenberg, Arthur M. (Committee member) / Graham, Steve (Committee member) / Arizona State University (Publisher)
Created2015
Description
War exacts a great social cost, not only upon its direct participants, but also upon the lives of the friends, family, and community of those who experience it. This cost is particularly evident in the increased frequencies of aggressive behaviors, including homicide, assault, and domestic violence, enacted by Western military veterans with posttraumatic stress disorder (PTSD). Similarly, among contemporary non-Westernized peoples, a cross-cultural conducted by Ember and Ember (1994) found a relationship between war and various forms of intragroup violence, including domestic violence, assaults, homicides, and violent sports. It is unknown, however, if this positive association between warfare and intragroup violence extends longitudinally for prehistoric populations uninfluenced by modern states.
To test Ember and Ember’s (1994) results in an archaeological culture, this study examines whether or not an association between war and intragroup violence was present during the Mississippian Period (ca. AD 1000-1450) of the Central Illinois Valley (CIV). The Mississippian Period of the CIV represents an ideal context for examining war and violence questions, as considerable evidence of war and violence has been amassed from archaeological and bioarchaeological analyses. High rates of skeletal trauma, fortification construction, and the placement of habitations sites in defendable areas indicate war was of particular concern during this period. Yet, little is known regarding the diachronic and synchronic variation in violence in this region.
In this research, skeletal remains representing 776 individuals from five CIV sites (Dickson Mounds, Larson, Berry, Crable, and Emmons) were analyzed for violence-related skeletal trauma, biodistance, and mortuary data. From the aggregation of these data, two models of intergroup violence and two models of intragroup violence were explored. The intergroup models examined were: 1) warfare victims from the local community and 2) warfare captives. The intragroup models assessed include: 1) domestic violence and 2) male-male fights. Results support the hypothesis that as intergroup violence increased during the Mississippian Period in the CIV, intragroup violence increased concomitantly. While warfare and intragroup violence occurred in low frequencies early in the Mississippian Period, after AD 1200, both intragroup and intergroup violence were likely endemic.
To test Ember and Ember’s (1994) results in an archaeological culture, this study examines whether or not an association between war and intragroup violence was present during the Mississippian Period (ca. AD 1000-1450) of the Central Illinois Valley (CIV). The Mississippian Period of the CIV represents an ideal context for examining war and violence questions, as considerable evidence of war and violence has been amassed from archaeological and bioarchaeological analyses. High rates of skeletal trauma, fortification construction, and the placement of habitations sites in defendable areas indicate war was of particular concern during this period. Yet, little is known regarding the diachronic and synchronic variation in violence in this region.
In this research, skeletal remains representing 776 individuals from five CIV sites (Dickson Mounds, Larson, Berry, Crable, and Emmons) were analyzed for violence-related skeletal trauma, biodistance, and mortuary data. From the aggregation of these data, two models of intergroup violence and two models of intragroup violence were explored. The intergroup models examined were: 1) warfare victims from the local community and 2) warfare captives. The intragroup models assessed include: 1) domestic violence and 2) male-male fights. Results support the hypothesis that as intergroup violence increased during the Mississippian Period in the CIV, intragroup violence increased concomitantly. While warfare and intragroup violence occurred in low frequencies early in the Mississippian Period, after AD 1200, both intragroup and intergroup violence were likely endemic.
ContributorsHatch, Mallorie Ann, 1983- (Author) / Buikstra, Jane (Thesis advisor) / Spielmann, Katherine (Committee member) / Carr, Christopher (Committee member) / Milner, George (Committee member) / Arizona State University (Publisher)
Created2015
Description
Node-link diagrams are widely used to visualize the relational structure of real world datasets. As identical data can be visualized in infinite ways by simply changing the spatial arrangement of the nodes, one of the important research topics of the graph drawing community is to visualize the data in the way that can facilitate people's comprehension. The last three decades have witnessed the growth of algorithms for automatic visualization. However, despite the popularity of node-link diagrams and the enthusiasm in improving computational efficiency, little is known about how people read these graphs and what factors (layout, size, density, etc.) have impact on their effectiveness (the usability aspect of the graph, e.g., are they easy to understand?). This thesis is comprehensive research to investigate the factors that affect people's understanding of node-link diagrams using eye-tracking methods. Three experiments were conducted, including 1) a pilot study with 22 participants to explore the layout and size effect; 2) an eye tracking experiment with 43 participants to investigate the layout, size and density effect on people's graph comprehension using abstract node-link diagram and generic tasks; and 3) an eye tracking experiment with the same participants to investigate the same effects using a real visualization analytic application. Results showed that participants' spatial reasoning ability had significant impact on people's graph reading performance. Layout, size, and density were all found to be significant effects under different task circumstances. The applicability of the eye tracking methods on visualization evaluation has been confirmed by providing detailed evidence that demonstrates the cognitive process of participants' graph reading behavior.
ContributorsLiu, Qing (Author) / McKenna, Anna (Thesis advisor) / Jennifer, Jennifer (Committee member) / Cooke, Nancy J. (Committee member) / Arizona State University (Publisher)
Created2015
Description
Sexual and social signals have long been thought to play an important role in speciation and diversity; hence, investigations of intraspecific communication may lead to important insights regarding key processes of evolution. Though we have learned much about the control, function, and evolution of animal communication by studying several very common signal types, investigating rare classes of signals may provide new information about how and why animals communicate. My dissertation research focused on rapid physiological color change, a rare signal-type used by relatively few taxa. To answer longstanding questions about this rare class of signals, I employed novel methods to measure rapid color change signals of male veiled chameleons Chamaeleo calyptratus in real-time as seen by the intended conspecific receivers, as well as the associated behaviors of signalers and receivers. In the context of agonistic male-male interactions, I found that the brightness achieved by individual males and the speed of color change were the best predictors of aggression and fighting ability. Conversely, I found that rapid skin darkening serves as a signal of submission for male chameleons, reducing aggression from winners when displayed by losers. Additionally, my research revealed that the timing of maximum skin brightness and speed of brightening were the best predictors of maximum bite force and circulating testosterone levels, respectively. Together, these results indicated that different aspects of color change can communicate information about contest strategy, physiology, and performance ability. Lastly, when I experimentally manipulated the external appearance of chameleons, I found that "dishonestly" signaling individuals (i.e. those whose behavior did not match their manipulated color) received higher aggression from unpainted opponents. The increased aggression received by dishonest signalers suggests that social costs play an important role in maintaining the honesty of rapid color change signals in veiled chameleons. Though the color change abilities of chameleons have interested humans since the time of Aristotle, little was previously known about the signal content of such changes. Documenting the behavioral contexts and information content of these signals has provided an important first step in understanding the current function, underlying control mechanisms, and evolutionary origins of this rare signal type.
ContributorsLigon, Russell (Author) / McGraw, Kevin J. (Committee member) / DeNardo, Dale F (Committee member) / Karsten, Kristopher B (Committee member) / Rutowski, Ronald L (Committee member) / Deviche, Pierre (Committee member) / Arizona State University (Publisher)
Created2015
Description
ABSTRACT
This dissertation examines contemporary U.S. women writing about war, with primarily women subjects and protagonists, from 1991-2013, in fiction, memoir, and media. The writers situate women at the center of war texts and privilege their voices as authoritative speakers in war, whether as civilians and soldiers trying to survive or indigenous women preparing for the possibility of war. I argue that these authors are rewriting scripts of war to reflect gendered experiences and opening new ways of thinking about war. Women Rewriting Scripts of War argues that Leslie Marmon Silko’s novel Almanac of the Dead juxtaposes an indigenous Story concept against a white industrialized national “Truth,” and indigenous women characters will resort to war if needed to oppose it. Silko’s and the other texts here challenge readers to unseat assumptions about the sovereignty of the U.S. and other countries, about the fixedness of gender, of capitalism, and of how humans relate to each other‒and how we should. I argue in Essay 3 that the script of “the body” or “the soldier” in military service can be expanded by moving toward language and concepts from feminist and queer theory and spectrums of gender and sexuality. This can contribute to positive change for all military members. In each of the texts, there are some similarities in connections with others. Connections enable solidarity for change, possibilities for healing, and survival; indeed, without connections with others to work together, survival is not possible. Changes to established economic structures become necessary for women in Barbara Kingsolver’s novel The Poisonwood Bible; I argue that women engaging in alternative modes of economy subvert the dominant economic constraints, gender hierarchies, and social isolation during and after war in the Congo. In Essay 5, I explore two fictional texts about the U.S. wars in Iraq and Afghanistan, Helen Benedict's novel Sand Queen and Katey Schultz’s short story collection Flashes of War. The connections in these women’s texts about war are not idealized, and they function as the antithesis to the fragmentation and isolation of postmodern texts.
This dissertation examines contemporary U.S. women writing about war, with primarily women subjects and protagonists, from 1991-2013, in fiction, memoir, and media. The writers situate women at the center of war texts and privilege their voices as authoritative speakers in war, whether as civilians and soldiers trying to survive or indigenous women preparing for the possibility of war. I argue that these authors are rewriting scripts of war to reflect gendered experiences and opening new ways of thinking about war. Women Rewriting Scripts of War argues that Leslie Marmon Silko’s novel Almanac of the Dead juxtaposes an indigenous Story concept against a white industrialized national “Truth,” and indigenous women characters will resort to war if needed to oppose it. Silko’s and the other texts here challenge readers to unseat assumptions about the sovereignty of the U.S. and other countries, about the fixedness of gender, of capitalism, and of how humans relate to each other‒and how we should. I argue in Essay 3 that the script of “the body” or “the soldier” in military service can be expanded by moving toward language and concepts from feminist and queer theory and spectrums of gender and sexuality. This can contribute to positive change for all military members. In each of the texts, there are some similarities in connections with others. Connections enable solidarity for change, possibilities for healing, and survival; indeed, without connections with others to work together, survival is not possible. Changes to established economic structures become necessary for women in Barbara Kingsolver’s novel The Poisonwood Bible; I argue that women engaging in alternative modes of economy subvert the dominant economic constraints, gender hierarchies, and social isolation during and after war in the Congo. In Essay 5, I explore two fictional texts about the U.S. wars in Iraq and Afghanistan, Helen Benedict's novel Sand Queen and Katey Schultz’s short story collection Flashes of War. The connections in these women’s texts about war are not idealized, and they function as the antithesis to the fragmentation and isolation of postmodern texts.
ContributorsStamper, Cambria A (Author) / Clarke, Deborah (Thesis advisor) / Hogue, Cynthia (Committee member) / Fonow, Mary Margaret (Committee member) / Arizona State University (Publisher)
Created2015
Description
Background: Heart failure is the leading cause of hospitalization in older adults and has the highest 30-day readmission rate of all diagnoses. An estimated 30 to 60 percent of older adults lose some degree of physical function in the course of an acute hospital stay. Few studies have addressed the role of posture and mobility in contributing to, or improving, physical function in older hospitalized adults. No study to date that we are aware of has addressed this in the older heart failure population.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
ContributorsFloegel, Theresa A (Author) / Buman, Matthew P (Thesis advisor) / Hooker, Steven (Committee member) / Dickinson, Jared (Committee member) / DerAnanian, Cheryl (Committee member) / McCarthy, Marianne (Committee member) / Arizona State University (Publisher)
Created2015