Hyperbolic dimension of Julia sets of meromorphic maps with logarithmic tracts

We prove that for meromorphic maps with logarithmic tracts (e.g. entire or meromorphic maps with a finite number of poles from class $\mathcal B$), the Julia set contains a compact invariant hyperbolic Cantor set of Hausdorff dimension greater than 1. Hence, the hyperbolic dimension of the Julia set is greater than 1.Comment: 7 pages, 1 figur

On the connectivity of the Julia sets of meromorphic functions

We prove that every transcendental meromorphic map f with a disconnected Julia set has a weakly repelling fixed point. This implies that the Julia set of Newton's method for finding zeroes of an entire map is connected. Moreover, extending a result of Cowen for holomorphic self-maps of the disc, we show the existence of absorbing domains for holomorphic self-maps of hyperbolic regions whose iterates tend to a boundary point. In particular, the results imply that periodic Baker domains of Newton's method for entire maps are simply connected, which solves a well-known open question.Comment: 34 pages, 10 figure

Displacement of plasma protein and conduction velocity in rats under action of acceleration forces and hypokinesia

The permeability of capillary vessels was investigated in order to determine if acceleration alone or following prolonged hypokinesia would induce changes in the vascular wall leading to the penetration by l-albumins and/or proteins with larger molecules. In rats undergoing action of +5 Gz accelerations, no increase in vascular permeability, as tested with the use of (Cr-5k)-globulin, was demostrated. In rats immobilized for 4 weeks before centrifugation, rather weak migration of (Cr-51)-globulin from the vessels was observed. Immobilization resulted also in lowering of conduction velocity in the sciatic nerve

Genre as a Lens to Becoming Better Leaders

When most people think of genre, they think of works that fall into categories such as fiction, nonfiction, etc. Genre typically is understood as the way in which a reader can recognize a specific text as falling into a category of similar texts, such as a plotline that focuses solely on the main character falling for a romantic interest being considered a romance novel. However, genre does not strictly have to pertain to physical text such as romance novels and does more work than simply categorizing a type of text. In simple terms, genre is a set of guidelines used by individual to explain, interpret, and negotiate interaction (Devitt, 576-577). As a collection of interactions involving communication between individuals, leadership, then, can be analyzed using the lens of genre. Through this perspective, leadership can be broken down into a system of genres – unique situations in which the conventions and characteristics of leadership must be applied to interactions, both in written and spoken forms. How might the theoretical concept of “genre” help us better understand leadership and help leaders interact more effectively

CoA protects against the deleterious effects of caloric overload in Drosophila

We developed a Drosophila model of T2D in which high sugar (HS) feeding leads to insulin resistance. In this model, adipose TG storage is protective against fatty acid toxicity and diabetes. Initial biochemical and gene expression studies suggested that deficiency in CoA might underlie reduced TG synthesis in animals during chronic HS feeding. Focusing on the Drosophila fat body (FB), which is specialized for TG storage and lipolysis, we undertook a series of experiments to test the hypothesis that CoA could protect against the deleterious effects of caloric overload. Quantitative metabolomics revealed a reduction in substrate availability for CoA synthesis in the face of an HS diet. Further reducing CoA synthetic capacity by expressing FB-specific RNAi targeting pantothenate kinase (PK orfumble) or phosphopantothenoylcysteine synthase (PPCS) exacerbated HS-diet-induced accumulation of FFAs. Dietary supplementation with pantothenic acid (vitamin B5, a precursor of CoA) was able to ameliorate HS-diet-induced FFA accumulation and hyperglycemia while increasing TG synthesis. Taken together, our data support a model where free CoA is required to support fatty acid esterification and to protect against the toxicity of HS diets

Engineering Patterns to Study Vascular Biology

Proper growth of blood vessels is critical for development, wound healing and homeostasis. This process is regulated by a variety of microenvironmental cues including growth factor signaling, cell-cell contacts and mechanical and biochemical signals from the extracellular matrix. The work presented in this dissertation encompasses the application of engineering principles to the study of angiogenesis and vascular biology within the contexts of tissue engineering and vascular disease. In Chapter 2, we present a novel strategy for generating a spatially patterned vascular network in vivo. Future development of clinically viable engineered tissues hinges on the ability to generate functional vasculature capable of delivering blood to parenchymal cells deep within the tissue. The vascularization strategy described here utilizes tissue constructs that contain patterned ‘cords’ of endothelial cells. Implantation of these constructs into mice leads to the formation of stable capillaries in a spatially controlled geometry. The capillaries become perfused with host blood as early as 3 days post implantation, remain stable for at least 28 days in vivo, are largely comprised of implanted endothelial cells, and are invested by α-SMA positive pericytes. We further demonstrate that spatial patterning of vascular architecture improves the function of engineered hepatic tissues. Specifically, co-implantation of patterned endothelial cell cords with primary hepatocyte aggregates suggested that organized vascular architecture significantly improved albumin promoter activity within the tissues. In Chapter 3, we describe the development of an organotypic vascular wall model and show that pulmonary arterial smooth muscle cells (PASMCs) isolated from patients with idiopathic pulmonary arterial hypertension (IPAH) exhibit a hyperproliferative phenotype in culture. While normal control PASMCs display Rac1-mediated growth control, the higher proliferation in IPAH PASMCs is dependent on increased RhoA activity. We observed that focal adhesion assembly and focal adhesion kinase signaling are abnormally increased in IPAH PASMCs and show that antagonizing adhesion signaling by direct inhibition of FAK abrogates IPAH PASMC hyperproliferation in vitro. In summary, our strategy for rapidly inducing the formation of spatially controlled capillaries comprises a novel technique for spatial control of vessel growth in vivo. Functional studies with engineered hepatic tissues also demonstrate the potential of this technique to be used in vascularizing engineered solid organs. Findings from our investigation into aberrant IPAH SMC proliferation suggest that a mechanosensitive proliferative control mechanism underlies IPAH etiology