Hybrid biomaterials with tuneable mechanical property gradients

Sol-gel hybrid materials are made up of covalently bonded and interpenetrating networks of organic and inorganic components and produce a synergy of the properties of those components above the nanoscale. By altering the ratio of inorganic to organic content, the mechanical properties can be tuned. Here, a silica-poly(tetrahydrofuran) hybrid system was developed with the aim to form a graded stiffness structure that could imitate the radial variation in stiffness of the intervertebral disc and address the unmet clinical need of intervertebral disc replacement. Hybrids were formed with a range of silica contents between 4 and 45 wt.%, varying from an elastomeric to a glassy material, with compressive stiffness between 2 and 200 MPa. High compressive strains are recoverable and mechanical properties were maintained on soaking up to 1.5 years and to 10000 cycles in compression. The hybrid surface was shown to support cell attachment and extract solutions containing the hybrid were non-cytotoxic. A novel synthesis method was developed to join hybrid sols during their gelation, forming a single specimen with a variation in silica content along its length, producing a corresponding variation in stiffness. Samples joined in this way were at least as strong as single phase samples in tension and compression. This exploits the gradual gelation process of the hybrid sol, which can also be used to create a successful ink for 3D extrusion printing: porous scaffolds were formed in this way with 27.7 wt.% SiO2. Meniscus and intervertebral disc replacement prototypes were formed and tested under cyclic loading at rates for comparison with human disc data.Open Acces

Reconstruction of an Arkansas Hopewellian Panpipe

Panpipes have been found in North America only on Hopewell sites. A particularly well preserved specimen from the Helena Crossing Site was described by James A. Ford. From this description a reconstruction which produced a true octave was made from native cane. Since the panpipe is a more primitive instrument than the flutes in use during Hopewell florescence, it is postulated that this instrument was used by shamans in the cult of ancestor worship

Characterization of immune cell distributions in mouse models of spontaneous breast tumors

As immunotherapy grows in popularity as a cancer treatment option, we need to further understand how immune cells interact with the tumor microenvironment and influence tumor progression. The goal of this thesis was to characterize the different immune, cellular, and structural components within the breast tumor tissues of two orthotopic (MCaP0008 and M3C) and one spontaneous (MMTV-PyVT) murine models of immunogenic breast cancer. Identification of the tumor components in question, including CD3+ lymphocytes, CD11b+ myeloid cells, CD31+ endothelial cells, αSMA+ cancer associated fibroblasts, Ki67+ cells, cleaved caspase-3+ cells, collagen-1, and hyaluronan, were done by immunohistochemistry (IHC)-immunofluorescence (IF) staining of frozen tumor tissues with appropriate antibodies and imaging with multispectral confocal microscopy. Quantification and further data analysis were performed using a custom MATLAB program designed by Dr. Mei Rosa Ng. Gaining understanding of these stromal compositions will allow for better utilization of these breast cancer mouse models in future experiments.2019-10-3

Planting, transitioning, and growing multiethnic churches

https://place.asburyseminary.edu/ecommonsatsdissertations/1881/thumbnail.jp

Emergent and divergent spaces in the Women’s March: the challenges of intersectionality and inclusion

This piece introduces the set of articles assembled from our call for Rapid Responses to the Women’s March on Washington circulated in February, 2017. Each addresses issues arising through collective expressions of protest. The Women’s March on Washington, organized on the twin principles of intersectionality and inclusion, acted as a flashpoint for the generation of emergent spaces to do politics differently. In the search for solidarity, tensions within groups and among individuals shaped the way in which resistance and protests were responded to and organized. The authors in this collection take up themes of intersectionality and inclusion/exclusion via politicizing the personal, contesting the state, and challenging simplistic notions of unity in solidarity

Is Social Rank Correlated With Cognitive Ability in Black-capped Chickadees?

Traditionally, dominant animals have been regarded as better competitors in all aspects of life, including cognition. However, the survival and reproductive advantages of being a dominant chickadee are surprisingly modest. It is possible that subordinate individuals compensate for the disadvantages of a lower rank with better cognitive abilities. If dominants are monopolizing prime food sources, subordinates may have developed better associative learning skills by learning to associate novel types of stimuli with food rewards. In this thesis, I asked whether dominance rank is correlated with cognitive ability in Black-capped Chickadees. I determined dominance rank in six flocks of six chickadees, and then tested each bird individually on two different associative learning tasks. I used artificial trees with holes that held food reward in both tasks. The first task was a colour associative learning task, in which birds learned that only holes marked with a specific colour contained a food reward. The second task was a spatial associative learning task, in which birds learned that only holes in specific locations contained a food reward. There were no differences in associative learning or spatial memory between dominant and subordinate birds, showing no support for the hypothesis that there are differences in learning and memory between chickadees of different dominance ranks

The Sweetest Words I Know

Illustration of straight and wavy red lineshttps://scholarsjunction.msstate.edu/cht-sheet-music/10525/thumbnail.jp