Webs of activity in online course design and teaching

In this study, we followed three faculty members' experiences with designing and teaching online courses for the first time. In order to complete the activity, the faculty members had to work -collaboratively with others across the university. Activity theory provided a framework within which to study faculty members' collaborative activities with members of different activity systems that had different goals, tools, divisions of labor and accountabilities. In concordance with activity theory, such differences led to contradictions, disturbances, and transformations in thinking and work activities. The results of the study have implications for individuals and systems undertaking technology integration in teaching

The supposed dissipation of figural imagery in Mamluk art: a study of Mamluk iconography

The arts of the Mamluks are considered a particularly rich field of study stretching over a nearly three hundred year period. Diverse in their make-up, the progression and development of this art began with strong Ayyubid influences that quickly evolved into a style that was uniquely Mamluk. While many historians have argued that figural imagery all but disappeared in these later progressions of Mamluk art, most notably following the reign of the Mamluk sultan al-Nasir Muhammad (1309-1341), the reality of these conclusions is much more complex. Indeed, the lack of conclusively dated materials from these later periods has been a significant factor in these early claims regarding Mamluk figural imagery. However, given the recent study released by Rachel Ward that re-dated Medieval Syrian and Egyptian glass, as well as a careful reexamination of other portable arts of this period, it becomes clear that the production of anthropomorphic and zoomorphic imagery was by no means halted during the reign of al-Nasir Muhammad, but rather was relegated to artwork that did not bear the official court titulature of amirs and sultans. In this sense, figural imagery played a important, albeit secondary, role in the visual expressions of the Mamluk ruling elite

Multiscale regulation of cellular mechanical properties

Thesis (Ph.D.)--Boston UniversityIn vivo, cells routinely experience mechanical stresses and strains in the form of circulatory pressure and flow, peristalsis ofthe gut, and airway inflation and deflation. Even on the microscale, all adherent cells apply contractile force to the extracellular matrix and to neighboring cells. Cells respond to these external forces both passively and actively. Passively, cells need to deform in a way that is tissue and function appropriate. Actively, cells use local mechanoreceptors present on their surface to trigger changes in global cell behavior. Dysregulation of cell responses to force are hallmarks of diseases such as atherosclerosis, asthma and cancer. Given the pluripotent role of cell mechanics in both normal cell behavior and disease, cell regulation of mechanical properties has become a major area of focus in biology. In this dissertation, we explore passive mechanical properties and active mechanical responses of cells on the subcellular, single cell and multicellular length scales. In Aim 1, we developed a new tool, called cell biomechanical imaging, for mapping intracellular stiffness and prestress. We have demonstrated a linear relationship between these two quantities, both at the whole cell and subcellular levels, which suggests prestress may be a unifying mechanism by which cells and tissues tune their mechanical properties. In Aim 2, we investigated how coordinated changes in cytoskeletal tension lead to cell reorientation. Previous research has shown that in response to strain applied through focal adhesions, the actin cytoskeleton promptly fluidizes and then slowly resolidifies. Using both experiments and a mathematical model, we found that repeated interplay ofthese phenomena was a driving force behind cytoskeletal reorganization during cell reorientation. It was previously hypothesized that the purpose of cytoskeletal remodeling in response to strain was to minimize changes in intracellular mechanical tension and maintain it at a preferred level. This feedback control mechanism, which balances forces between the cell and its microenvironment, is termed "tensional homeostasis." The dominant paradigm in vascular biology is that tensional homeostasis exists across multiple length and time scales. However, our results from Aim 2 challenged this idea; reoriented cells did not maintain steady levels of contractile force. In Aim 3, we investigated tensional homeostasis and its existence at multiple length scales. We found that cells do not have a preferred level of tension at the subcellular or single cell levels. However, in a cluster of confluent cells, contractile tension is maintained, the more so as cluster size increases. Together, the results of this dissertation emphasize the importance ofa multiscale approach to mechanobiology. Cells and tissue are hierarchically ordered systems that use mechanical stress (prestress) to tune their mechanical properties and responses across lengthscales. Thus, it is important to consider not just the behavior of separate components of each of these systems, but the behaviors that emerge when they interact with one another

An fMRI Analysis of the Subjective Experience of Recent and Remote Autobiographical Memories

Autobiographical memory plays a crucial role in shaping one’s identity and maintaining one’s sense of continuity from past to present. This study strove to deepen the understanding of the neural correlates underlying individual subjective experience of autobiographical memory. We recruited twenty healthy adult participants, who were asked to generate memory cues for both objects and locations from their present and early life (recent/remote). Participants were subsequently shown these cues and asked to recall the associated memory while in an fMRI scanner. Participants were finally asked to rate the memories on various subjective categories (i.e. arousal, frequency, importance, vividness)(behavioral ratings). Our hypotheses considered: 1) behavioral ratings would be greater for recent, than remote memories. 2) that there would be greater overall activation in the lateral prefrontal cortex, (LPFC) with earlier memories, compared to recent memories, due to increased effort. 3) additionally, that there would be more sensory cortical activity (e.g., ventral/dorsal visual stream) in recent memories, due to more recent activation. In terms of behavioral ratings, we confirmed out hypothesis; that recent memories tended to be rated higher in subjective categories than early memories. In terms of fMRI data, we found there was greater overall activation for location memory compared to object memory, as well as confirming our hypothesis for regarding: greater overall activation for recent memories compared to earlier memories. We additionally found that increased ratings for several factors, most significantly arousal, of recent memories may relate to increased functional connectivity between the LPFC, hippocampus and visual cortex. Contrary to our hypothesis, we found greater overall activation for LPFC during recent memory retrieval, as opposed to early memories; our findings suggesting that arousal may play a part in this increased activation for recent memories

The Neural Sequalae of Subjectively Experiencing Autobiographical Memories from the Remote Past and Recent Present using fMRI

Autobiographical memory is central to one\u27s sense of self and continuity from past to present. Despite this, there is little research on the neural correlates underlying individual subjective experience of autobiographical memory and how that is related to brain phenomena (i.e., activity, communication). The purpose of this study was to help minimize this gap. We recruited twenty healthy adult participants, who were asked to generate memory cues (1-3 word descriptions) for locations and objects from their early and recent life. After 24 hours, participants were shown these cues then asked to recall the appropriate memory while in an fMRI scanner. Subsequently, participants were then asked to rate the memories on various subjective categories (i.e. arousal, frequency, importance, vividness). We hypothesized that there would be greater overall activation with earlier memories, compared to recent memories in brain regions responsible for memory reinstatement (e.g., the hippocampus, amygdala, and ventrolateral/medial prefrontal cortices), as earlier memories tend to be encoded and consolidated for longer. Results from behavioral ratings indicated that recent memories were rated higher than early memories in most subjective categories. In terms of fMRI data, we found there was greater overall activation for recent memories as compared to earlier memories. We also found greater overall activation for location memory compared to object memory. When using the subjective ratings to probe neural activity and communication, we found significant correlations between arousal in certain brain regions (e.g., medial prefrontal cortex, amygdala, hippocampus) for different categories of memory. Contrary to our hypothesis, we found greater overall activation for recent memories, as opposed to early memories; our findings suggest that arousal may play a part in this increased activation for recent memories

Parental Deployment and Healthcare Utilization in Adolescents with Migraines and Other Somatic Symptoms

Somatic symptoms in adolescents are associated with psychosocial stress. Parental military deployment can function as a stressor for adolescents. A retrospective cohort study was developed exploring relationships between health care utilization, a proxy for symptomatology, and sponsor deployment in adolescents with somatic symptoms. Data was obtained from the Military Health System Data Repository. Migraine headaches was the most common somatic symptom diagnosis. Parental deployment was overall associated with a 27% decrease in visits for somatic symptoms. For adolescents whose sponsor was female, deployment was associated with a 34% decrease in visits. This pattern is inconsistent with prior research on somatic symptoms and psychosocial stressors. Potential causes of this discrepancy are discussed in the context of military family life

Identification of a conditionally essential heat shock protein in Escherichia coli

Protein D48.5 was recognized as a heat-inducible protein of Escherichia coli during the screening of a group of random, temperature-inducible Mud-Lac fusion mutants. Physiological and genetic analysis demonstrated that (i) the structural gene for this protein, designated htpI, is a member of the o32-dependent heat shock regulon, (ii) at 37[deg]C the synthesis of protein D48.5 is nearly constitutive, increasing slightly with growth rate in media of different composition, and (iii) this protein is essential for growth at high temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31386/1/0000299.pd

Cellulose: from biocompatible to bioactive material

International audienceSince the papyri, cellulose has played a significant role in human culture, especially as paper. Nowadays, this ancient product has found new scientific applications in the expanding sector of paper-based technology. Among paper-based devices, paper-based biosensors raise a special interest. The high selectivity of biomolecules for target analytes makes these sensors efficient. Moreover, simple paper-based detection devices do not require hardware or specific technical skill. They are inexpensive, rapid, user-friendly and therefore highly promising for providing resource-limited settings with point-of-care diagnostics. The immobilization of biomolecules onto cellulose is a key step in the development of these sensing devices. Following an overview of cellulose structural features and physicochemical properties, this article reviews current techniques for the immobilization of biomolecules on paper membranes. These procedures are categorized into physical, biological and chemical approaches. There is no universal method for biomolecule immobilization. Thus, for a given paper-based biochip, each strategy can be considered

First imported Plasmodium ovale malaria in Central America: case report of a Guatemalan soldier and a call to improve its accurate diagnosis

The Mesoamerican Ministers of Health have set 2020 as the target for malaria elimination to be achieved in the region. Imported malaria cases are a potential threat to countries attempting elimination or working to prevent resurgence. We report the first imported Plasmodium ovale infection with molecular confirmation in Central America, which occurred in a Guatemalan soldier that had been deployed in Africa. The obstacles for its diagnosis using the standard microscopy technique and the need to improve its detection are discussed