Riparian zones are ecotones between terrestrial and aquatic ecosystems. Processes in streams are strongly influenced by riparian forest communities, age, stage and structure. Temperate forests across much of North America, including riparian areas, are recovering from historic land clearing with many stands in the stem-exclusion phase of development in which...
Climate change is occurring at an increasingly rapid rate, with impacts heightened in the cold regions of the world including the Arctic. Warming effects are widespread, with one impacted process – freeze-thaw cycles – increasing in frequency and potentially triggering additional changes in permafrost soils that have previously acted as...
Public lands in the Pacific Northwest are managed for multiple uses including timber production, recreation and aesthetic value, maintaining wildlife habitat, conserving native species, and carbon storage. Wildfires impact large areas encompassing broad environmental conditions. Interactions among underlying environmental gradients and alteration of overstory competition by fire of varying severities...
Landscape positions have been used to determine soil properties. My soil study in Monteverde on the Pacific slope of Costa Rica was designed to examine soil-landscape relationships for sites with various land use histories and management. Soil pits were dug at Nacimiento y Vida, Crandell, Curi-cancha, La Calandria, and Finca...
An increase in anthropogenic activities since the industrial revolution, primarily due to burning of fossil fuels and changes in land cover, has resulted in a steady increase in the global mean atmospheric CO2 concentrations. While there is unequivocal scientific evidence on global warming and its multidimensional impacts on natural and...
Natural products from both terrestrial and marine sources represent a significant source of novel drug leads, and have previously been developed into clinically-approved agents for the treatment of various human diseases. This work represents the biological characterization of the mechanistic basis for activity of several natural product structures in models...
Two distinct strategies were explored for the enantioselective synthesis of α-heteroatom substituted alkyl boronic esters by stereoselective reagent-controlled homologation using transient chiral carbenoid reagents CHYMX (Y = heteroatom, X = nucleofuge, M = electrofuge). In the first case, a stereospecific reagent-controlled homologation (sStReCH) approach to α-alkoxyalkylboronates using α-metalated S,O- and...
Coibamide A is a methyl-stabilized cyclic depsipeptide with a lariat side chain that was isolated from a marine cyanobacterium as part of an International Cooperative Biodiversity Groups program based in Panama. Previous testing of this potent and selective growth-inhibitory agent in the National Cancer Institute (NCI) in vitro 60 human...
Amyotrophic lateral sclerosis (ALS) is a devastating disease characterized by the progressive degeneration of motor neurons. Dominantly-inherited mutations to the antioxidant enzyme Cu,Zn superoxide dismutase (SOD1) cause 3-6% of all ALS cases. The complete mechanism behind the toxicity of mutant SOD1 remains unclear, although significant evidence points to aberrant or...
Chemicals must be bioavailable for there to be a potential for exposure and consequent risk to human or environmental health. Passive sampling devices (PSDs) are used to quantify the time-integrated concentration of bioavailable contaminants. We demonstrate that PSDs can be paired with the zebrafish developmental toxicity bioassay to produce site-specific,...