Browsing by Author "Barber, Richard T"

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Open Access
Barnacle cement: a polymerization model based on evolutionary concepts.
(2009-11) Dickinson, Gary H.
The tenacity by which barnacles adhere has sparked a long history of scientific investigation into their adhesive mechanisms. To adhere, barnacles utilize proteinaceous cement that rapidly polymerizes and forms adhesive bonds underwater, and is insoluble once polymerized. Although progress has been made towards understanding the chemical properties of cement proteins, the biochemical mechanisms of cement polymerization remain largely unknown. In this dissertation, I used evolutionary concepts to elucidate barnacle cement polymerization. Well-studied biological phenomena (blood coagulation in vertebrates and invertebrates) were used as models to generate hypotheses on proteins/biochemical mechanisms involved in cement polymerization. These model systems are under similar selective pressures to cement polymerization (life or death situations) and show similar chemical characteristics (soluble protein that quickly/efficiently coagulates). I describe a novel method for collection of unpolymerized cement. Multiple, independent techniques (AFM, FTIR, chemical staining for peroxidase and tandem mass spectroscopy) support the validity of the collection technique. Identification of a large number of proteins besides ‘barnacle cement proteins’ with mass spectrometry, andobservations of hemocytes in unpolymerized cement inspired the hypothesis that barnacle cement is hemolymph. A striking biochemical resemblance was shown between barnacle cement polymerization and vertebrate blood coagulation. Clotted fibrin and polymerized cement were shown to be structurally similar (mesh of fibrous protein) but biochemically distinct. Heparin, trypsin inhibitor and Ca2+ chelators impeded cement polymerization, suggesting trypsin and Ca2+ involvement in polymerization. The presence/activity of a cement trypsin-like serine protease was verified and shown homologous to bovine pancreatic trypsin. Protease activity may activate cement structural precursors, allowing loose assembly with other structural proteins and surface rearrangement. Tandem mass spectrometry and Western blotting revealed a homologous protein to human coagulation factor XIII (fibrin stabilizing factor: transglutaminase that covalently cross-links fibrin monomers). Transglutaminase activity was verified and may covalently cross-link assembled cement monomers. Similar to other protein coagulation systems, heritable defects occur during cement polymerization. High plasma protein concentration combined with sub-optimal enzyme, and/or cofactor concentrations and sub-optimal physical/muscular parameters (associated with hemolymph release) results in improperly cured cement in certain individuals when polymerization occurs in contact with low surface energy silicone and its associated leached molecules.
Open Access
Business Solutions to Environmental Issues: A Model Solution to Resource Conflicts in the Powersports Industry
(2002) Woodson, Peter
This project explores the use of a for-profit business model and emerging technologies to resolve resource conflicts in the powersports industry. While the business will ultimately address all three segments of the powersports market, initial business development will focus on the PWC segment. A complete 40-page model business plan is provided with supporting investor presentation slides. The hope is that this project can be used as a baseline for future students to address environmental issues through the creation of for-profit products, services, or complete businesses. This business plan was one of five finalists in the 2002 Duke Startup Challenge, and is being pursued as a potentially viable venture.
Open Access
Can supercomputer model output be used routinely in fisheries management and conservation biology: - A vision of what's possible-
(2006) Sakagami, Taichiro
Current physical and biological oceanographic models have progressed in the last five years with satellite observations, high-performance computing, and assimilation methods. These recent high-resolution models are now accurate enough to provide information that could be very useful for fisheries management and conservation biology. Unfortunately, because model output is very large and complex, users struggle to use this information effectively for managing fisheries and forecasting fish abundance. Animations of model output enable users to better understand and interpret huge data sets. I created a web interface (http://moray.ml.duke.edu/projects/PacClimVar/) to manipulate an animation of sea surface temperatures from 1993 to 2004. Data come from the NASA project, “Impact of ocean variability on ocean circulation, marine ecosystems, and living resources.” With this interface, managers and scientists can easily visualize physical oceanographic variability, and adapt fishing effort to ocean conditions.
Open Access
The Creation of a Regulatory Regime for Offshore Wind Energy in the United States
(2006) Peloso, Margaret E.
The Energy Policy Act of 2005 empowered the Secretary of the Interior through the Minerals Management Service to regulate the development of renewable energy on the Outer Continental Shelf of the United States. The goal of this paper is to review the development of offshore wind energy and develop a set of recommendations for the Minerals Management Service as it proceeds with the development of regulations for renewable energy generation on the Outer Continental Shelf. In creating recommendations for the Minerals Management Service, the historical uses of the Outer Continental Shelf, proposals for wind energy development in the United States, and wind energy development in Europe were reviewed. A substantial portion of this Masters Project was submitted to the Minerals Management Service in the public comment period that closed on February 28, 2006. A copy of the comments as submitted to the Minerals Management Service is available from the author upon request.