Matching Items (136)
Description
Filtration for microfluidic sample-collection devices is desirable for sample selection, concentration, preprocessing, and downstream manipulation, but microfabricating the required sub-micrometer filtration structure is an elaborate process. This thesis presents a simple method to fabricate polydimethylsiloxane (PDMS) devices with an integrated membrane filter that will sample, lyse, and extract the DNA from microorganisms in aqueous environments. An off-the-shelf membrane filter disc was embedded in a PDMS layer and sequentially bound with other PDMS channel layers. No leakage was observed during filtration. This device was validated by concentrating a large amount of cyanobacterium Synechocystis in simulated sample water with consistent performance across devices. After accumulating sufficient biomass on the filter, a sequential electrochemical lysing process was performed by applying 5VDC across the filter. This device was further evaluated by delivering several samples of differing concentrations of cyanobacterium Synechocystis then quantifying the DNA using real-time PCR. Lastly, an environmental sample was run through the device and the amount of photosynthetic microorganisms present in the water was determined. The major breakthroughs in this design are low energy demand, cheap materials, simple design, straightforward fabrication, and robust performance, together enabling wide-utility of similar chip-based devices for field-deployable operations in environmental micro-biotechnology.
ContributorsLecluse, Aurelie (Author) / Meldrum, Deirdre (Thesis advisor) / Chao, Joseph (Thesis advisor) / Westerhoff, Paul (Committee member) / Arizona State University (Publisher)
Created2011
Description
Single cell phenotypic heterogeneity studies reveal more information about the pathogenesis process than conventional bulk methods. Furthermore, investigation of the individual cellular response mechanism during rapid environmental changes can only be achieved at single cell level. By enabling the study of cellular morphology, a single cell three-dimensional (3D) imaging system can be used to diagnose fatal diseases, such as cancer, at an early stage. One proven method, CellCT, accomplishes 3D imaging by rotating a single cell around a fixed axis. However, some existing cell rotating mechanisms require either intricate microfabrication, and some fail to provide a suitable environment for living cells. This thesis develops a microvorterx chamber that allows living cells to be rotated by hydrodynamic alone while facilitating imaging access. In this thesis work, 1) the new chamber design was developed through numerical simulation. Simulations revealed that in order to form a microvortex in the side chamber, the ratio of the chamber opening to the channel width must be smaller than one. After comparing different chamber designs, the trapezoidal side chamber was selected because it demonstrated controllable circulation and met the imaging requirements. Microvortex properties were not sensitive to the chambers with interface angles ranging from 0.32 to 0.64. A similar trend was observed when chamber heights were larger than chamber opening. 2) Micro-particle image velocimetry was used to characterize microvortices and validate simulation results. Agreement between experimentation and simulation confirmed that numerical simulation was an effective method for chamber design. 3) Finally, cell rotation experiments were performed in the trapezoidal side chamber. The experimental results demonstrated cell rotational rates ranging from 12 to 29 rpm for regular cells. With a volumetric flow rate of 0.5 µL/s, an irregular cell rotated at a mean rate of 97 ± 3 rpm. Rotational rates can be changed by altering inlet flow rates.
ContributorsZhang, Wenjie (Author) / Frakes, David (Thesis advisor) / Meldrum, Deirdre (Thesis advisor) / Chao, Shih-hui (Committee member) / Wang, Xiao (Committee member) / Arizona State University (Publisher)
Created2011
Description
Laboratory automation systems have seen a lot of technological advances in recent times. As a result, the software that is written for them are becoming increasingly sophisticated. Existing software architectures and standards are targeted to a wider domain of software development and need to be customized in order to use them for developing software for laboratory automation systems. This thesis proposes an architecture that is based on existing software architectural paradigms and is specifically tailored to developing software for a laboratory automation system. The architecture is based on fairly autonomous software components that can be distributed across multiple computers. The components in the architecture make use of asynchronous communication methodologies that are facilitated by passing messages between one another. The architecture can be used to develop software that is distributed, responsive and thread-safe. The thesis also proposes a framework that has been developed to implement the ideas proposed by the architecture. The framework is used to develop software that is scalable, distributed, responsive and thread-safe. The framework currently has components to control very commonly used laboratory automation devices such as mechanical stages, cameras, and also to do common laboratory automation functionalities such as imaging.
ContributorsKuppuswamy, Venkataramanan (Author) / Meldrum, Deirdre (Thesis advisor) / Collofello, James (Thesis advisor) / Sarjoughian, Hessam S. (Committee member) / Johnson, Roger (Committee member) / Arizona State University (Publisher)
Created2012
Description
Consideration of both biological and human-use dynamics in coupled social-ecological systems is essential for the success of interventions such as marine reserves. As purely human institutions, marine reserves have no direct effects on ecological systems. Consequently, the success of a marine reserve depends on managers` ability to alter human behavior in the direction and magnitude that supports reserve objectives. Further, a marine reserve is just one component in a larger coupled social-ecological system. The social, economic, political, and biological landscape all determine the social acceptability of a reserve, conflicts that arise, how the reserve interacts with existing fisheries management, accuracy of reserve monitoring, and whether the reserve is ultimately able to meet conservation and fishery enhancement goals. Just as the social-ecological landscape is critical at all stages for marine reserve, from initial establishment to maintenance, the reserve in turn interacts with biological and human use dynamics beyond its borders. Those interactions can lead to the failure of a reserve to meet management goals, or compromise management goals outside the reserve. I use a bio-economic model of a fishery in a spatially patchy environment to demonstrate how the pre-reserve fisheries management strategy determines the pattern of fishing effort displacement once the reserve is established, and discuss the social, political, and biological consequences of different patterns for the reserve and the fishery. Using a stochastic bio-economic model, I demonstrate how biological and human use connectivity can confound the accurate detection of reserve effects by violating assumptions in the quasi-experimental framework. Finally, I examine data on recreational fishing site selection to investigate changes in response to the announcement of enforcement of a marine reserve in the Gulf of California, Mexico. I generate a scale of fines that would fully or partially protect the reserve, providing a data-driven way for managers to balance biological and socio-economic goals. I suggest that natural resource managers consider human use dynamics with the same frequency, rigor, and tools as they do biological stocks.
ContributorsFujitani, Marie (Author) / Abbott, Joshua (Thesis advisor) / Fenichel, Eli (Thesis advisor) / Gerber, Leah (Committee member) / Anderies, John (Committee member) / Arizona State University (Publisher)
Created2014
Description
Single cell analysis has become increasingly important in understanding disease onset, progression, treatment and prognosis, especially when applied to cancer where cellular responses are highly heterogeneous. Through the advent of single cell computerized tomography (Cell-CT), researchers and clinicians now have the ability to obtain high resolution three-dimensional (3D) reconstructions of single cells. Yet to date, no live-cell compatible version of the technology exists. In this thesis, a microfluidic chip with the ability to rotate live single cells in hydrodynamic microvortices about an axis parallel to the optical focal plane has been demonstrated. The chip utilizes a novel 3D microchamber design arranged beneath a main channel creating flow detachment into the chamber, producing recirculating flow conditions. Single cells are flowed through the main channel, held in the center of the microvortex by an optical trap, and rotated by the forces induced by the recirculating fluid flow. Computational fluid dynamics (CFD) was employed to optimize the geometry of the microchamber. Two methods for the fabrication of the 3D microchamber were devised: anisotropic etching of silicon and backside diffuser photolithography (BDPL). First, the optimization of the silicon etching conditions was demonstrated through design of experiment (DOE). In addition, a non-conventional method of soft-lithography was demonstrated which incorporates the use of two positive molds, one of the main channel and the other of the microchambers, compressed together during replication to produce a single ultra-thin (<200 µm) negative used for device assembly. Second, methods for using thick negative photoresists such as SU-8 with BDPL have been developed which include a new simple and effective method for promoting the adhesion of SU-8 to glass. An assembly method that bonds two individual ultra-thin (<100 µm) replications of the channel and the microfeatures has also been demonstrated. Finally, a pressure driven pumping system with nanoliter per minute flow rate regulation, sub-second response times, and < 3% flow variability has been designed and characterized. The fabrication and assembly of this device is inexpensive and utilizes simple variants of conventional microfluidic fabrication techniques, making it easily accessible to the single cell analysis community.
ContributorsMyers, Jakrey R (Author) / Meldrum, Deirdre (Thesis advisor) / Johnson, Roger (Committee member) / Frakes, David (Committee member) / Arizona State University (Publisher)
Created2012
Description
This paper studies the change in social diversity and interaction space from the Classic to Postclassic periods in the Mimbres Valley and East Mimbres Area. Between the Classic and Postclassic periods the Mimbres region of the American Southwest exhibits an increase in diversity of ceramic wares. Previous research suggests that increased diversity of ceramics indicates a more diverse community, which could pose challenges to local social interaction (Nelson et al. 2011). I am interested in whether the architecture of plazas, focal points of communities' social structures, change in response to the growing social diversity. To examine this, I quantify the diversity of painted ceramics at Classic and Postclassic villages as well as the extent of the enclosure of plazas. I find that there is a definite shift towards greater plaza enclosure between the Classic and Postclassic periods. I conclude this paper with a discussion of possible interpretations of this trend regarding the social reactions of Mimbres communities to the changes which reshaped the region between the Classic and Postclassic periods.
ContributorsHarkness, Rebecca Jean (Author) / Nelson, Margaret (Thesis director) / Hegmon, Michelle (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2015-05
Description
This project created a teaching curriculum resource guide for using the popular series, The Hunger Games, in 6th-8th grade classrooms to introduce cultural issues such as child soldiers and international development to students. Studies have shown that literature can cultivate empathy and encourage youth to act. This combined with the expanding phenomenon of participatory culture and fandom activism as outlined by Henry Jenkins demonstrate the potential for youth to learn and act when given the opportunity and resources to do so. The curriculum is composed of three units: The first is a three-week reading of the books with various activities for students to really understand the narrative and source text. The second and third units address the issues of child soldiers and international development using The Hunger Games as a framework and a keystone to build connections so that these complex issues are accessible to youth. This project is a first step in the development of a curriculum that spans the full trilogy and covers a variety of current event topics.
ContributorsSimpson, Rebecca (Author) / Sivak, Henry (Thesis director) / Blasingame, James (Committee member) / Nelson, Margaret (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-05
Description
Background: Latinos represent 40.8% of the population in Phoenix (U.S. Census Bureau Population Division, 2010). South Phoenix, also known as the South Mountain Village, defined in geographical terms as area zip codes 85040 and 85042; is a predominantly Latino community comprised of mixed citizenship status households. During the 2010 United States Census 60.3% of the population in South Phoenix identified as Latino, 25.75% of the total population was foreign born. Of the foreign born population, 88.95% were of Latin American origin (United States Census Bureau, 2007-2011 American Community Survey). Understanding how Latino immigrants perceive differences in health between their communities in country of origin and communities in the United States is largely unknown. Irrespective of political positions, understanding how Latino immigrants perceive personal health and the health of their communities is of interest to inform public policy and implement needed interventions in the
public health sphere.
Methods: Semi-structured interviews were collected from 55 adults from the South Phoenix community between November 2009 and September 2010. Interviews were digitally recorded with participant permission and transcribed. Of those collected, 48 transcribed interviews were analyzed using a codebook designed by the researcher. Percent agreement evaluated inter-rater reliability.Results: Latino immigrants in South Phoenix largely agree that health quality is heavily dependent on personal responsibility and not an intrinsic attribute of a given place. Emotional contentedness and distress, both factors of mental health, are impacted by cross-cultural differences between Latino and U.S. culture systems.
Conclusions: As people’s personal perceptions of differences in health are complex concepts influenced by personal backgrounds, culture, and beliefs, attempting to demark a side of the border as ‘healthier’ than the other using personal perceptions is overly simplified and misses central concepts. Instead, exploration of individual variables impacting health allowed this study to gain a more nuanced understanding in how people determine quality of both personal and environmental health. While Latino migrants in South Phoenix largely agree that health is based on personal responsibility and choices, many nonetheless experience higher levels of contentedness and emotional health in their country of origin.
public health sphere.
Methods: Semi-structured interviews were collected from 55 adults from the South Phoenix community between November 2009 and September 2010. Interviews were digitally recorded with participant permission and transcribed. Of those collected, 48 transcribed interviews were analyzed using a codebook designed by the researcher. Percent agreement evaluated inter-rater reliability.Results: Latino immigrants in South Phoenix largely agree that health quality is heavily dependent on personal responsibility and not an intrinsic attribute of a given place. Emotional contentedness and distress, both factors of mental health, are impacted by cross-cultural differences between Latino and U.S. culture systems.
Conclusions: As people’s personal perceptions of differences in health are complex concepts influenced by personal backgrounds, culture, and beliefs, attempting to demark a side of the border as ‘healthier’ than the other using personal perceptions is overly simplified and misses central concepts. Instead, exploration of individual variables impacting health allowed this study to gain a more nuanced understanding in how people determine quality of both personal and environmental health. While Latino migrants in South Phoenix largely agree that health is based on personal responsibility and choices, many nonetheless experience higher levels of contentedness and emotional health in their country of origin.
ContributorsGray, Laurel (Author) / Wutich, Amber (Thesis director) / Quiroga, S. Seline (Committee member) / Nelson, Margaret (Committee member) / Slade, B. Alexandra (Committee member) / Barrett, The Honors College (Contributor) / College of Liberal Arts and Sciences (Contributor)
Created2013-05
Description
The Mimbres tradition of southwestern New Mexico, underwent what can be characterized as continuity with change, a form of non-collapse transformation, from the Late Pithouse (ca. 550-1000 CE) to Classic (ca. 1000-1130 CE) period. Both transitions are characterized by large-scale shifts in housing, settlement patterns, pottery, and mortuary customs.The goal of this thesis is to evaluate changes in the intrasite and inter-site frequencies of selected nonlocal items in Mimbres burial contexts dating to the Late Pithouse and Classic periods. Because those living in the Mimbres region seem to have dramatically changed the ways in which they lived and expressed their social identities it is reasonable to assume that their mortuary use of these high-value objects might have also transformed.
ContributorsOwen, Paige Elizabeth (Author) / Nelson, Ben (Thesis director) / Nelson, Margaret (Committee member) / Russell, Will (Committee member) / Barrett, The Honors College (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2013-12
DescriptionThis paper provides an analysis of the differences in impacts made by companies that promote their sustainability efforts. A comparison of companies reveals that the ones with greater supply chain influence and larger consumer bases can make more concrete progress in terms of accomplishment for the sustainability realm.
ContributorsBeaubien, Courtney Lynn (Author) / Anderies, John (Thesis director) / Allenby, Brad (Committee member) / Janssen, Marco (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05