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Full-Text Articles in Physical Sciences and Mathematics

Engineering Photosystem I Complexes For Use In Bio-Hybrid Dye-Sensitized Solar Cells, Richard Franklin Simmerman Aug 2015

Engineering Photosystem I Complexes For Use In Bio-Hybrid Dye-Sensitized Solar Cells, Richard Franklin Simmerman

Doctoral Dissertations

Increasing global population, growing per capita energy needs, diminishing fossil fuels, and climate change collectively will require new, innovative, and sustainable alternatives to meet the world’s growing energy needs. One of the most promising yet simple approaches are dye-sensitized solar cells (DSSCs). However, conventional DSSCs use semi-conductor anodes sensitized with complex synthetic organometallic dyes. Most dyes utilize ruthenium complexes to absorb photons, which upon excitation, inject electrons into the anode, while holes migrate to the cathode via liquid electrolyte. However, these dyes are expensive, difficult to make, and resource-limited. This dissertation focuses on replacing synthetic dyes with the naturally occurring, …


De Novo Design And Engineering Of Functional Metal And Porphyrin-Binding Protein Domains, Bernard Howard Everson Feb 2015

De Novo Design And Engineering Of Functional Metal And Porphyrin-Binding Protein Domains, Bernard Howard Everson

Dissertations, Theses, and Capstone Projects

In this work, I describe an approach to the rational, iterative design and characterization of two functional cofactor-binding protein domains. First, a hybrid computational/experimental method was developed with the aim of algorithmically generating a suite of porphyrin-binding protein sequences with minimal mutual sequence information. This method was explored by generating libraries of sequences, which were then expressed and evaluated for function. One successful sequence is shown to bind a variety of porphyrin-like cofactors, and exhibits light- activated electron transfer in mixed hemin:chlorin e6 and hemin:Zn(II)-protoporphyrin IX complexes. These results imply that many sophisticated functions such as cofactor binding and electron …


Divergent Responses Of Atlantic Coastal And Oceanic Synechococcus To Iron Limitation, Katherine R. M. Mackey, Anton F. Post, Matthew R. Mcilvin, Gregory A. Cutter, Seth G. John, Mak A. Saito Jan 2015

Divergent Responses Of Atlantic Coastal And Oceanic Synechococcus To Iron Limitation, Katherine R. M. Mackey, Anton F. Post, Matthew R. Mcilvin, Gregory A. Cutter, Seth G. John, Mak A. Saito

OES Faculty Publications

Marine Synechococcus are some of the most diverse and ubiquitous phytoplankton, and iron (Fe) is an essential micronutrient that limits productivity in many parts of the ocean. To investigate how coastal and oceanic Atlantic Synechococcus strains acclimate to Fe availability, we compared the growth, photophysiology, and quantitative proteomics of two Synechococcus strains from different Fe regimes. Synechococcus strain WH8102, from a region in the southern Sargasso Sea that receives substantial dust deposition, showed impaired growth and photophysiology as Fe declined, yet used few acclimation responses. Coastal WH8020, from the dynamic, seasonally variable New England shelf, displayed a multitiered, hierarchical cascade …


Understanding Ocean Acidification Impacts On Organismal To Ecological Scales, Andreas J. Andersson, David I. Kline, Peter J. Edmunds, Stephen D. Archer, Nina Bednarsek, Robert C. Carpenter, Meg Chadsey, Philip Goldstein, Andrea G. Grottoli, Thomas P. Hurst, Andrew L. King, Janet E. Kübler, Ilsa B. Kuffner, Katherine R.M. Mackey, Bruce A. Menge, Adina Paytan, Ulf Riebesell, Astrid Schnetzer, Mark E. Warner, Richard C. Zimmerman Jan 2015

Understanding Ocean Acidification Impacts On Organismal To Ecological Scales, Andreas J. Andersson, David I. Kline, Peter J. Edmunds, Stephen D. Archer, Nina Bednarsek, Robert C. Carpenter, Meg Chadsey, Philip Goldstein, Andrea G. Grottoli, Thomas P. Hurst, Andrew L. King, Janet E. Kübler, Ilsa B. Kuffner, Katherine R.M. Mackey, Bruce A. Menge, Adina Paytan, Ulf Riebesell, Astrid Schnetzer, Mark E. Warner, Richard C. Zimmerman

OES Faculty Publications

Ocean acidification (OA) research seeks to understand how marine ecosystems and global elemental cycles will respond to changes in seawater carbonate chemistry in combination with other environmental perturbations such as warming, eutrophication, and deoxygenation. Here, we discuss the effectiveness and limitations of current research approaches used to address this goal. A diverse combination of approaches is essential to decipher the consequences of OA to marine organisms, communities, and ecosystems. Consequently, the benefits and limitations of each approach must be considered carefully. Major research challenges involve experimentally addressing the effects of OA in the context of large natural variability in seawater …


Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill Jan 2015

Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill

OES Faculty Publications

Isotopic discrimination against 13C during photosynthesis is determined by a combination of environmental conditions and physiological mechanisms that control delivery of CO2 to RUBISCO. This study investigated the effects of light, flow, dissolved inorganic carbon (DIC) concentration, and its speciation, on photosynthetic carbon assimilation of Zostera marinaL. (eelgrass) using a combination of laboratory experiments and theoretical calculations leading to a mechanistic understanding of environmental conditions that influence leaf carbon uptake and determine leaf stable carbon isotope signatures δ13C. Photosynthesis was saturated with respect to flow at low velocity ~ 3 cm s-1, but …