3D bioprinting a PCL/13-93B3 glass composite and its potential use as a bio-ink

A major limitation of using synthetic scaffolds in tissue engineering is little growth of incorporated cells in the interior of the scaffold, resulting in insufficient angiogenesis in the scaffold interior. Recently, cells have been 3D bioprinted concurrently with biomaterials to produce a cellularized, bioactive, angiogenic 3D environment. This thesis describes a novel solvent-extrusion method for printing polycaprolactone (PCL)/bioactive borate glass composite as a biomaterial for a cell-laden scaffold. Bioactive borate glass was added to a mixture of PCL and organic solvent to make an extrudable paste, creating scaffolds measuring 10×10×1 mm3 in overall dimensions with pore sizes ranging from 100-300 μm. We compared depositing hydrogel droplets to depositing hydrogel filaments in between the PCL/borate glass composite filaments. Degradation of the composite scaffold with and without the presence of hydrogel was investigated by soaking the scaffold in cell culture medium. The weight loss of the scaffold together with formation of a hydroxyapatite-like layer on the surface shows the excellent bioactivity of the scaffold. This work demonstrates that incorporating borate glass to increase the angiogenic capacity of the fabricated scaffolds is feasible. We also compared cell survival and viability between the composite bio-ink to two commonly used hydrogels, Matrigel and Pluronic F127. The viability and proliferation of cells in the different biomaterials were analyzed with different methods demonstrating that cell viability was similar between the different bio-inks. This 3D bioprinting method shows a high potential to create a bioactive, highly angiogenic 3D environment required for complex and dynamic interactions that govern the cell’s behavior in vivo --Abstract, page iii

On the public discourse of religion : an analysis of Christianity in the United Kingdom

Debates over the involvement of religion in the public sphere look set to be one of the defining themes of the 21st century. But while religious issues have attracted a large degree of scholarly attention, the public discourse of religion itself, in terms of the effort to assert and legitimize a role for faith in the public realm, has remained notably under-researched. This article marks an initial step to address this deficiency by deconstructing the public discourse of Christianity in the United Kingdom. It argues that, while appealing for representation on the grounds of liberal equality, the overall goal of this discourse is to establish a role for itself as a principal source of moral authority, and to exempt itself from the evidentially-based standards and criteria that govern public life

A decision support framework to assess and prioritize recovery actions for salmon in the Puget Sound

Protecting functioning habitats and restoring degraded habitats are critical actions for salmon and Puget Sound recovery. Restoration alone cannot keep up with habitat loss and water quality degradation from development and the pressures of anticipated population growth and future climate. We need a framework for prioritizing diverse projects and programs that takes into account the complexity of the science, competing stakeholder goals, treaty obligations, and the need for regulatory harmonization. As part of the Tulalip Tribes Harmonization project, we present a decision support framework based on three core principles. First the framework must assess ecosystem conditions across diverse indicators and co-benefits. Second, the framework must simulate the effects of diverse actions and trends - including regulatory, restoration, and future pressures on ecosystems. Finally, the framework must be flexible and open as the expertise to build, maintain, sustain, and evolve indicator models will always be spread across a wide swath of scientists, stakeholders, managers and regulators, resulting in many independent systems that should be leveraged by the framework, not recreated. The framework is built on the Ecosystem Management Decision Support system (EMDS) developed by the USDA Forest Service over 25 years ago. We describe the architecture of the framework and report on a concept project that used it to evaluate designs for a transportation project in Snohomish county. This will illustrate both the workflow paradigm of framework and how it can work with an external, specialized indicator modeling system, the Ecosystem Diagnosis and Treatment (EDT) system. The habitat model was used to estimate the value of habitat and key population indicators for Chinook salmon in response to multiple project designs. Finally, we lay out the iterative (in scale, indicators, modeling and action types) plan for development of the framework over the next decade, emphasizing use cases and challenges

Historical and contemporary demography of leaf-toed geckos (Phyllodactylidae: Phyllodactylus) in the Mexican dry forest

Disentangling the relative influence of historical versus contemporary processes shaping the spatial distribution of genetic variation is critical if we are to effectively mitigate key biodiversity issues. We utilize a comprehensive approach based on different molecular marker types and analytical methods to understand the demographic consequences of recent habitat fragmentation in a spatially explicit context. We focus our efforts on native leaf-toed geckos (Phyllodactylus tuberculosus saxatilis) throughout fragmented habitat in the tropical dry forest of northern Mexico as recent evidence suggests that geographic ranges for these geckos may be much smaller than currently realized. However, no data are available regarding recent shifts in demographic trends and how these trends may correspond with recent fragmentation and introductions of non-native gecko species (Hemidactylus). Mitochondrial DNA sequences reveal substantial historical genetic divergence over a small geographic area (\u3c40 km). We find evidence for an increase in contemporary versus historical migration rates based on 10 microsatellite loci, but evidence that many populations suffer from recent reductions in effective population sizes. Landscape genetic analyses find that contemporary migration rates are significantly more correlated with the landscape versus historical migration rates or mtDNA divergence, suggesting that individuals have altered their dispersal routes in response to recent habitat changes. Taken together, this study suggests that long-term female philopatry, recent habitat fragmentation, and possibly introductions of non-native gecko species all contribute to the demographic patterns and the high degree of differentiation observed over fine-spatial scales in Mexican leaf-toed geckos

Landscape Genetics of Leaf-Toed Geckos in the Tropical Dry Forest of Northern Mexico

Habitat fragmentation due to both natural and anthropogenic forces continues to threaten the evolution and maintenance of biological diversity. This is of particular concern in tropical regions that are experiencing elevated rates of habitat loss. Although less well-studied than tropical rain forests, tropical dry forests (TDF) contain an enormous diversity of species and continue to be threatened by anthropogenic activities including grazing and agriculture. However, little is known about the processes that shape genetic connectivity in species inhabiting TDF ecosystems. We adopt a landscape genetic approach to understanding functional connectivity for leaf-toed geckos (Phyllodactylus tuberculosus) at multiple sites near the northernmost limit of this ecosystem at Alamos, Sonora, Mexico. Traditional analyses of population genetics are combined with multivariate GIS-based landscape analyses to test hypotheses on the potential drivers of spatial genetic variation. Moderate levels of within-population diversity and substantial levels of population differentiation are revealed by FST and Dest. Analyses using structuresuggest the occurrence of from 2 to 9 genetic clusters depending on the model used. Landscape genetic analysis suggests that forest cover, stream connectivity, undisturbed habitat, slope, and minimum temperature of the coldest period explain more genetic variation than do simple Euclidean distances. Additional landscape genetic studies throughout TDF habitat are required to understand species-specific responses to landscape and climate change and to identify common drivers. We urge researchers interested in using multivariate distance methods to test for, and report, significant correlations among predictor matrices that can impact results, particularly when adopting least-cost path approaches. Further investigation into the use of information theoretic approaches for model selection is also warranted

Highly Ionized High Velocity Clouds: Intergalactic Gas in the Local Group or Distant Gas in the Galactic Halo?

We have recently identified several high velocity (V < -100 km/s) clouds in the directions of Mrk 509 and PKS 2155-304 that have unusual ionization properties. The clouds exhibit strong C IV absorption with little or no detectable low ion (C II, Si II) absorption or H I 21cm emission. As the closest known analog to the outer diffuse halos of damped Ly-alpha absorbers and the low H I column density metal line absorption systems seen in the spectra of high redshift quasars, these "C IV-HVCs" present unique opportunities for relating the conditions within the Milky Way halo and nearby intergalactic gas to the properties of galactic halos at higher redshift. The C IV-HVCs have ionization properties consistent with photoionization by extragalactic background radiation, though some contribution by collisional ionization within a hot plasma cannot be ruled out. The clouds are probably low density [n(H) ~ 10^-4 cm^-3], large [greater than several kiloparsecs], and mostly ionized [n(HI)/n(H) ~ 10^-3] regions located well beyond the neutral gas layer of the Galaxy. The presence of weak H I-HVCs detected through 21cm emission near both sight lines indicates that the C IV-HVCs trace the extended, ionized, low density regions of the H I-HVCs. Several lines of evidence, including very low thermal pressures (P/k ~ 2 cm^-3 K), favor a location for the C IV-HVCs in the Local Group or very distant Galactic halo.Comment: AASTEX manuscript and tables, 55 pages, 8 postscript figures. Astrophysical Journal, in pres