The potential applications of mesenchymal stem cells (MSCs) have been widely advocated, however, many barriers hinder their clinical utilization. Enhancement of the homing of human MSCs (hMSCs) to the target tissues remains a clinical challenge. To overcome this hurdle, the mechanisms responsible for migration and engraftment of hMSCs have to be defined. My study aimed to explore both the underlying mechanisms and means of enhancing the migration of hMSCs. A graft versus host disease (GvHD) injury model and a novel orthotopic neuroblastoma model were established to delineate the distinct property of hMSCs homing towards either injured or cancerous tissues. This highly specific homing process was further revealed to be in a CXCR4-dependent manner. Notably, a novel gene, exchange protein directly activated by cAMP (Epac), was demonstrated to be actively involved in the hMSCs homing process. hMSCs expressed functional Epac and its activation significantly enhanced the migration and adhesion of hMSCs. Furthermore, Epac activation directly contributed to the chemotactic response of hMSCs to SDF-1, suggesting that Epac is linked to the stromal cell derived factor-1 (SDF-1) signaling cascades. Importantly, the homing of hMSCs towards injured tissues in vivo could be dramatically increased by Epac activation. hMSCs are adherent cells and their migration to distant tissues thus requires detachment into a suspension state. This disruption of cell-extracellular matrix interaction, known as anoikis stress, triggers programmed cell death, leading to a marked decrease in the efficiency of cell trafficking and engraftment. Anoikis stress induced massive cell death has emerged as the major challenge in the application of hMSCs. How some of the hMSCs can overcome this adversity and migrate towards distant destinations remains largely unexplored. It was observed that the surviving hMSCs circumvented anoikis stress by forming self-supporting cellular aggregates. Compared to adherent hMSCs, aggregated-hMSCs had better migratory response to both SDF-1α and SDF-1α analogue (CTCE-0214). Such enhanced migratory effect was proven to be CXCR4-dependent both in vitro and in vivo by using a CXCR4 specific antagonist (AMD3100). Although the viability of hMSCs under anoikis stress dramatically decreased, CTCE-0214 could promote cell survival and facilitate the migration of hMSCs towards injured targets. This phenomenon could be partially explained by the increase in anti-apoptosis effect via up-regulated Bcl-2 expression and autophagy activation under CTCE-0214 treatment. The exact effects of hMSCs on tumor growth and progression have long been controversial. Significant fasten growth and promoted metastasis of neuroblastoma in vivo was observed in hMSCs co-transplanted mice in this study. Reciprocally, hMSCs could not only be recruited by primary tumor, but also be selectively attracted by metastatic loci. This recruitment was significantly reduced when hMSCs were pre-treated with AMD3100, suggesting that the SDF-1/CXCR4 axis was a prime mover in this process. In summary, my study demonstrated that the migratory property of hMSCs could be enhanced by novel intrinsic and extrinsic factors using both in vitro and in vivo models. This study provides a new prospective on MSCs biology during the ex vivo manipulation process and I proposed means to overcome some of these hindrance so we can maximize the efficacy of clinical MSCs application in the future. / published_or_final_version / Paediatrics and Adolescent Medicine / Doctoral / Doctor of Philosophy

In recent years, many ethnic Armenians from Iran have come to the US as refugees, resettling in a diverse landscape that already includes large Armenian and Iranian diaspora communities. Soon after arrival, they also interface with US institutions in a home visit from a refugee resettlement case worker. In this thesis I adopt constructivist understandings of identity-in-interaction to examine the identity work that older Armenian Iranian immigrants do during these visits, reproduced here as life history interviews. I argue that Armenian Iranians use the home visit to discursively construct an Armenian Iranian identity that addresses the tension between institutional and community pressure to represent themselves as uniquely discriminated against in Iranian society while still identifying with an Iranian national identity. The more localized and temporary identities and interactional roles that speakers – including the researcher – adopt in the interviews also contribute to gender asymmetries in the interactions to the effect that men most often command the floor. Therefore, while the home visit format provides insight into the ways Armenian Iranians articulate an identity that is at least in part “Iranian” amidst normative pressures to do otherwise, it can also translate into an interaction that privileges men’s perspectives and allows them to largely determine its direction and content. / text

The thesis is an anthropological exploration of the role of religion in Filipino transnational migration and diaspora. The thesis takes the interpretive approach, drawing from a variety of disciplines such as religious studies, sociology, and geography to frame a holistic view of religion as a “lived” experience that connects religious dispositions, symbols and ritual performance to the diaspora’s place-making and home-making. It weaves together anthropology’s conceptual strands of space, place, symbols and ritual to present a view of Filipino migrant sociality and personhood not as constituted by disparate fragmented experiences but as as a tapestry of woven symbols and meanings that shape their diasporic life, even as they themselves continuously shape their own experiences. The thesis’ ethnography is based on participant observation among Filipino migrants between 2007 and 2010 in New Zealand and Singapore. It focuses on the celebration of the Santacruzan and Santo Niño-Sinulog fiesta in New Zealand and Simbang Gabi novena masses in Singapore to examine how Filipino cultural forms of expression connect and mix with notions of homeland, family, home, sacred domain and identity as these have been adapted, recreated, and spatially inscribed in their transnational journeys. 6 The ethnography examines the interplay and connection between Filipino folk religiosity, family and social networks. It looks at how the deeply held folk Christian notions of kapalaran (destiny), swerte (luck), bahala na (whatever God allows will happen /come what may God will take care) and imagery of may awa ang Diyos (a compassionate God) are enmeshed in the migrant exercise of agency, reflexive discourse, risk-taking, resilience and meaningmaking in the diaspora. It demonstrates that among Filipino migrants, material and communication flows are manifestations of religious dispositions that support enduring family commitment and reciprocity. It shows that financial and social capital provided by families and social networks for migrants are supported by prayers for sacred assistance and blessings, indicating that the Filipino migrants’ exercise of agency is familial and sacral rather than individual and secular. As a dominant Philippine lowland tradition, the fiesta is the locus of sacralmaterial linkages constituted by Filipino home symbols, such as sacred icons, costumes, cultural performance, semantic expressions, and food. By examining the fiesta, its organisation and structure of power relations, the thesis explores the metaphoric parallels and symbolic articulations between two homes in migrants’ diasporic consciousness, and the significant role of sacred symbols in aiding and facilitating the maintenance and inscription of ‘Filipino’ identity in a foreign land. Diaspora identity is a socially and spatially inscribed identity. For Filipinos, it is inscribed through sacred icons and fiesta celebrations in sacred sites.

Every day, thousands of unauthorized migrants are repatriated from the United States to Mexican cities along the U.S.-Mexico border. Suspended at the border, unauthorized migrants must make a quick decision: attempt another clandestine border crossing, return to their hometown in Mexico, or choose some other alternative such as stay in the city where they have been repatriated. In this research, I seek to better understand the decision-making process behind these intentions to further migrate following repatriation. I ask several interrelated questions: What are the factors that lead some repatriated migrants to state that they will attempt another crossing of the U.S.-Mexico border? Others to state that they will return to their hometowns in Mexico? And still others to state that they do not know what they will do? As gender is a constitutive aspect of migration and social reality more generally, I also pay special attention to how gender and family constraints help shape the decision-making process behind further migration intentions. For one year, I conducted 70 in-depth semi-structured qualitative interviews with repatriated migrants at a migrant shelter in Nogales, Sonora (Mexico), interviewing roughly equal shares of women and men (37 women, 33 men). When I was not interviewing, I also engaged in direct and participant observation at the shelter that I documented as field notes. I asked respondents to share their experiences with me from their clandestine crossing of the Arizona-Sonora border, to their apprehension experience with the Border Patrol or other U.S. authorities, and finally to their experiences following repatriation to Nogales, Sonora. Through this research, I found that both gender and the family played central roles in migration- and repatriation-related activities in different and complex ways. Gender intrinsically shaped respondents' experiences in their journey in the semi-arid Arizona-Sonora desert, their interactions with Border Patrol agents and other U.S. authorities, and the decision-making process following repatriation. Further, family constraints, such as dependent children in the U.S., critically affected further migration intentions in gendered ways. As part of my work, I provide several policy recommendations regarding the repatriation of unauthorized migrants to border cities such as Nogales, Sonora.

Abstract The intellectual assets underpinning the modern knowledge economy are not normally associated with activities in the primary sector. This raises the question whether resourcebased developing countries are eternally relegated to the Also-Runs in global competition or at least whether they need to disassociate themselves from their economic mainstay in order for catch-up to materialise. The answer to this question is of paramount importance to many developing countries, especially in Latin America and Africa. This analysis contributes to the discussion in two novel ways. The first is the focus on technological trajectories that start in or around resource-based activities and subsequently become more knowledge intensive. Hence the study shows the direct contribution resource-based activities make towards the development of a knowledge economy. The second is the attempt systematically to compare technological trajectories in Africa’s most sophisticated economy with those in three Latin American countries at different stages of development. By contrast, this study concentrates on countries from continents that are customarily lumped together in the failure category. It analyses examples of technological learning and focuses on what works (not), and why, and whether insights from a collection of case studies can inform a broader policy discussion about how best to reconcile the demands of the knowledge economy with intensive resource endowments.

The objective of my thesis is to explore the use of the conducting polymer, polypyrrole, in neural applications. In addition a supplementary aspect of dissertation will involves understanding the effects of external stimuli on nervous system cells, with the ultimate goal of designing therapeutic systems for nerve regeneration. In normal development and peripheral nervous system repair, nerves encounter naturally occurring chemical, physical, and electrical stimuli. Polypyrrole (PPy) has attracted much attention for use in numerous biomedical applications as it presents chemical, physical and electrical stimuli. In addition, PPy is particularly exciting because the extent by which chemical, physical, and electrical cues are presented to the injured nerve can be easily tailored. Thus, conducting polymers are excellent scaffolds for the exploration of how the cellular components of the nervous system (i.e., Schwann cells and neurons) interact with chemical, topographical, and electrical stimuli. This dissertation covers three main objectives and is supplemented by two additional topics. The two additional topics explore the effect stimuli present on the conducting polymer PPy have on neural interfaces. These fundamental studies use computational modeling to gain a better understanding of cellular motility on substrates containing different stimuli. Both topics are covered in the appendices of this dissertation. With regards to the three main objectives, I first characterized and optimized the electrochemical synthesis of the conducting polymer, PPy, for Schwann cell biocompatibility. Next, I investigated the effect the application of electrical cues through PPy has on Schwann cell migration. In addition to investigating the effect of the direct electrical current on Schwann cells I also considered the effect that electrical stimulation provided by PPy has on protein adsorption. Finally, I developed a hybrid PPy material that will provide advantageous properties for neural interfaces. Specifically, I describe the development of a polypyrrole:poly-(lactic-co-glycolic) acid blend for neural applications. In summary the three specific objectives covered in my thesis are: Specific Aim 1: Characterize and optimize the electrochemical synthesis of the conducting polymer, polypyrrole, for Schwann cell biocompatibility Specific Aim 2: Determine the effect of electrical stimulation on Schwann cell migration Specific Aim 3: Develop polypyrrole:poly-(lactic-co-glyolic) acid blends for neural engineering applications. / text

Cloud computing has grown in prevalence from recent years due to its concept of computing as a service, thereby, allowing users to offload the infrastructure management costs and tasks to a cloud provider. Cloud providers leverage server virtualization technology for efficient resource utilization, faster provisioning times, reduced energy consumption, etc. Cloud computing inherits a key feature of server virtualization which is the live migration of virtual machines (VMs). This technique allows transferring of a VM from one host to another with minimal service interruption. However, live migration is a complex process and with a cloud management software used by cloud providers for management, there could be a significant influence on the migration process. This thesis work aims to investigate the complex process of live migration performed by the hypervisor as well as the additional steps involved when a cloud management software or platform is present and form a timeline of these collection of steps or phases. The work also aims to investigate the performance of these phases, in terms of time, when migrating VMs with different sizes and workloads. For this thesis, the Kernel-based Virtual Machine (KVM) hypervisor and the OpenStack cloud software have been considered. The methodology employed is experimental and quantitative. The essence of this work is investigation by network passive measurements. To elaborate, this thesis work performs migrations on physical test-beds and uses measurements to investigate and evaluate the migration process performed by the KVM hypervisor as well as the OpenStack platform deployed on KVM hypervisors. Experiments are designed and conducted based on the objectives to be met. The results of the work primarily include the timeline of the migration phases of both the KVM hypervisor and the OpenStack platform. Results also include the time taken by each migration phase as well as the total migration time and the VM downtime. The results indicate that the total migration time, downtime and few of the phases increase with increase in CPU load and VM size. However, some of the phases do not portray any such trend. It has also been observed that the transfer stage alone does not contribute and influence the total time but every phase of the process has significant influence on the migration process. The conclusions from this work is that although a cloud management software aids in managing the infrastructure, it has notable impact on the migration process carried out by the hypervisor. Moreover, the migration phases and their proportions not only depend on the VM but on the physical environment as well. This thesis work focuses solely on the time factor of each phase. Further evaluation of each phase with respect to its resource utilization can provide better insight into probable optimization opportunities.

This dissertation is a nine-month ethnographic study of migrant families' literacies and corresponding value systems. Specifically, while I found that formal education is strongly valued among Mexican migrant groups, it is considered more a marker of prestige than a means to self-realization or economic improvement. In turn, socially transmitted skills and consejos (advice) are more important to migrant communities' survival and personal and material advancement. In order to demonstrate the role of social literacies and the irony that schooled literacy takes in the lives of many rural Mexicans, I trace the historical development of my field site, the town of Villachuato in the state of Michoacán, from its inception as a Spanish-owned hacienda, through its liberation and subsequent small-scale farming initiatives following the Mexican Revolution, and on into the current history of those farms' failure as a result of transnational economic influences like NAFTA. While more and more members of the Villachuato community are being pushed across the Mexico-U.S. border in search of work, public school teachers in rural Mexico are frustrated by rising drop-out rates and perceived student apathy. However, while teachers advocate formal education as the best means of self-improvement, students in Villachuato schools do not find the curriculum relevant to their lives. Rather, they adopt those schooled lessons that they find helpful (i.e., reading and writing skills that help them read street signs and navigate government and commercial bureaucracies); but they actively resist the value systems of meritocracy and personal identity development implicit in public education. By considering the ways in which local communities interface with dominant institutional literacies, this study supports efforts within the New Literacy Studies to unpack the complexities of globalized literacy practices. Further, the discrepancies between Villachuato citizens' priorities and those of their schools suggest important implications for educational policy on both sides of the U.S.-Mexico border.

A non-linear edge-preserving solution to the least-squares migration problem with sparseness constraints is introduced. The applied formalism explores Curvelets as basis functions that, by virtue of their sparseness and locality, not only allow for a reduction of the dimensionality of the imaging problem but which also naturally lead to a non-linear solution with significantly improved signalto-noise ratio. Additional conditions on the image are imposed by solving a constrained optimization problem on the estimated Curvelet coefficients initialized by thresholding. This optimization is designed to also restore the amplitudes by (approximately) inverting the normal operator, which is like-wise the (de)-migration operators, almost diagonalized by the Curvelet transform.

Recent years have witnessed the large number of Chinese immigrants in Canada. However, talk about the return migration of Chinese immigrants is circulating within the Canada's Chinese communities, especially among Chinese immigrants who have obtained Canadian academic credentials. This inquiry explores ten Chinese immigrants' perceptions about their immigration and living experiences in Canada. My goal is to understand, from a social-cultural-historical context, the phenomenon of Chinese-Canadian return migration among recent Chinese immigrants in Canada. The theoretical framework is derived primarily from Bourdieu's capital theory and his critical approach to the concept of habitus . Drawing on an interpretative, qualitative approach, I examine social, cultural, historical forces that influence the ways these Chinese immigrants perceive, negotiate and reposition themselves in facing various challenges and struggles. Traditionally, research on return migration of Chinese immigrants in Canada has focused on the economic and social integration of immigrants in the host country. I argue that "Chinese cultural habitus", such as the profound influence of Confucianism and Taoism that Chinese immigrants inherited, played critical roles in their actions, attitudes and decision-making about their return migration. I collected the participants' narratives for a one and half year period from August 2006 to March 2008 primarily through open-ended interviews, and various documentation such as field notes, reflexive notes and Canadian Statistics. Analyses of the data suggest that the unrecognized foreign credentials and the limited social capital of Chinese immigrants are the primary factors that disadvantage their social mobility. Chinese cultural values and beliefs have great impact on Chinese immigrants' perceptions and behaviors during their journey of crossing different social spaces, assuming different positionings and negotiating among their multiple identities.