Sam E. Stephens results 18
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Human and Porcine Marginal Chordal Forces in a Vacuum Based Physiological In Vitro Mitral Valve ModelNARA Subscribed
Introduction This study aimed to quantitatively investigate the role of marginal chordae of the mitral valve during static closure by analyzing the force within these chordae and its potential correlation with the transvalvular pressure. Materials and Methods Porcine (n = 10) and human (n = 4) mitral valves were mounted in a saddle-shaped annulus clamp, while an in vitro system was utilized to replicate a physiological systoli...
Purpose Cardiovascular phantoms are used in biomedical research and development applications, allowing for complex geometries to be studied in a controlled environment. The various layers of human tissue have been difficult to mimic in these phantoms. In this study, a novel dual-layer cardiovascular phantom is created. Methods The interior lumen is 3D printed using an elastic vat-photopolymerization resin and cast within an in...
Marine megafauna species are affected by a wide range of anthropogenic threats. To evaluate the risk of such threats, species’ vulnerability to each threat must first be determined. We build on the existing threats classification scheme and ranking system of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species by assessing the vulnerability of 256 marine megafauna species to 23 at‐sea threat...
Genetic diversity is the foundation of biodiversity, and preserving it is therefore fundamental to conservation practice. However, global conservation efforts face significant challenges integrating genetic and genomic approaches into applied management and policy. As collaborative partnerships are increasingly recognized as key components of successful conservation efforts, we explore their role and relevance in the Australia...
The Toxicology Investigators Consortium 2022 Annual ReportNARA Subscribed
Development of Custom Wall-Less Cardiovascular Flow Phantoms with Tissue-Mimicking GelNARA Subscribed
Purpose Flow phantoms are used in experimental settings to aid in the simulation of blood flow. Custom geometries are available, but current phantom materials present issues with degradability and/or mimicking the mechanical properties of human tissue. In this study, a method of fabricating custom wall-less flow phantoms from a tissue-mimicking gel using 3D printed inserts is developed. Methods A 3D blood vessel geometry examp...
Fine root dynamics across pantropical rainforest ecosystemsNARA Subscribed
Fine roots constitute a significant component of the net primary productivity (NPP) of forest ecosystems but are much less studied than aboveground NPP. Comparisons across sites and regions are also hampered by inconsistent methodologies, especially in tropical areas. Here, we present a novel dataset of fine root biomass, productivity, residence time, and allocation in tropical old‐growth rainforest sites worldwide, measured u...
Convergence of bark investment according to fire and climate structures ecosystem vulnerability to future changeNARA Subscribed
Fire regimes in savannas and forests are changing over much of the world. Anticipating the impact of these changes requires understanding how plants are adapted to fire. In this study, we test whether fire imposes a broad selective force on a key fire‐tolerance trait, bark thickness, across 572 tree species distributed worldwide. We show that investment in thick bark is a pervasive adaptation in frequently burned areas across...
Evaluation of terrestrial carbon cycle models for their response to climate variability and to CO 2 trendsNARA Subscribed
The purpose of this study was to evaluate 10 process‐based terrestrial biosphere models that were used for the IPCC fifth Assessment Report. The simulated gross primary productivity ( GPP ) is compared with flux‐tower‐based estimates by Jung et al . [ Journal of Geophysical Research 116 (2011) G00J07] ( JU 11). The net primary productivity ( NPP ) apparent sensitivity to climate variability and atmospheric CO 2 trends is diagn...
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