Faculty Research

Permanent URI for this collection

Browse

Recent Submissions

Now showing 1 - 5 of 73
  • Item
    What measurements of energy transfer across non-covalent contacts in proteins reveal about the energy landscape
    (2023-11-27) Poudel, Humanath; Leitner, David M
    Determining rates of energy transfer across non-covalent contacts in a protein can provide information about dynamics of the contact at equilibrium. We investigate the relation between rates of energy transfer across polar contacts and contact dynamics for the WW domain, dominated by beta-strands, and compare with previous results for the helical villin headpiece subdomain, HP36. Overall, rates of energy transfer across hydrogen bonded contacts are found to be inversely proportional to the variance of the length of the contact. Due to the proportionality, change in dynamics of a non-covalent contact, and entropy associated with the dynamics, arising from change in state of the protein or mutation can be estimated from the measurement of change in the rate of energy transfer across the contact.
  • Item
    Intraspecific phytochemical variation shapes community and population structure for specialist caterpillars
    (2016) Glassmire, Andrea E.; Jeffrey, Christopher S.; Forister, Matthew L.; Parchman, Thomas L.; Nice, Christopher C.; Jahner, Joshua P.; Wilson, Joseph S.; Walla, Thomas R.; Richards, Lora A.; Smilanich, Angela M.; Leonard, Michael D.; Morrison, Colin R.; Simbana, Wilmer; Salagaje, Luis A.; Dodson, Craig D.; Miller, Jim S.; Tepe, Eric J.; Villamarin-Cortez, Santiago; Dyer, Lee A.
    Chemically mediated plant-herbivore interactions contribute to the diversity of terrestrial communities and the diversification of plants and insects. While our understanding of the processes affecting community structure and evolutionary diversification has grown, few studies have investigated how trait variation shapes genetic and species diversity simultaneously in a tropical ecosystem. We investigated secondary metabolite variation among subpopulations of a single plant species, Piper kelleyi (Piperaceae), using high-performance liquid chromatography (HPLC), to understand associations between plant phytochemistry and host-specialized caterpillars in the genus Eois (Geometridae: Larentiinae) and associated parasitoid wasps and flies. In addition, we used a genotyping-by-sequencing approach to examine the genetic structure of one abundant caterpillar species, Eois encina, in relation to host phytochemical variation. We found substantive concentration differences among three major secondary metabolites, and these differences in chemistry predicted caterpillar and parasitoid community structure among host plant populations. Furthermore, E.encina populations located at high elevations were genetically different from other populations. They fed on plants containing high concentrations of prenylated benzoic acid. Thus, phytochemistry potentially shapes caterpillar and wasp community composition and geographic variation in species interactions, both of which can contribute to diversification of plants and insects.
  • Item
    Nanographene and Graphene Nanoribbon Synthesis via Alkyne Benzannulations
    (Molecules, 2019) Senese, Amber D.; Chalifoux, Wesley A.
    The extension of -conjugation of polycyclic aromatic hydrocarbons (PAHs) via alkyne benzannulation reactions has become an increasingly utilized tool over the past few years. This short review will highlight recent work of alkyne benzannulations in the context of large nanographene as well as graphene nanoribbon synthesis along with a brief discussion of the interesting physical properties these molecules display.
  • Item
    Tsuji-Trost Cyclization of Disulfonamides: Synthesis of 12-Membered, 11-Membered, and Pyridine-Fused Macrocyclic Triamines
    (ACS Omega, 2019) Ali, Rameez; Anugu, Sreenivasa R.; Chawla, Reena; Demillo, Violeta G.; Goulinet-Mateo, Florian; Gyawali, Sagar; Hamal, Sunil; Jones, Dylan E.; Lamprecht, Katrin; Le, Truc D. T.; Lumangtad, Liezel A.; Pflug, Nicholas C.; Sama, Alekhya; Scarbrough, Emily D.; Bell, Thomas W.
    Macrocyclic triamine disulfonamides can be synthesized by double Tsuji-Trost N-allylation reaction of open-chain disulfonamides with 2-alkylidene-1,3-propanediyl bis(carbonates). The previously used Atkins-Richman macrocyclization method generally gives lower yields and requires more tedious purification of the product. Solvent, palladium source, ligand, and concentration have all been varied to optimize the yields of two key 12-membered ring bioactive compounds, CADA and VGD020. The new approach tolerates a wide range of functional groups and gives highest yields for symmetrical compounds in which the acidities of the two sulfonamide groups are matched, although the yields of unsymmetrical compounds are still generally good. The method has also been extended to the synthesis of 11-membered rings, pyridine-fused macrocycles, and products bearing an ester or aryl substituent on the exocyclic double bond.
  • Item
    Dynamic Windows Based on Reversible Metal Electrodeposition with Enhanced Functionality
    (Journal of The Electrochemical Society, 2019) Islam, Shakirul M.; Fini, Christine N.; Barile, Christopher J.
    Electronically tintable windows increase the energy efficiency and comfort of buildings and automobiles. Recently, dynamic windows harnessing reversible metal electrodeposition have been explored as a viable alternative to electrochromic materials. In this manuscript, we first construct 25 cm(2) dynamic windows with two tin-doped indium oxide (ITO) working electrodes, a metal frame counter electrode, and an aqueous-based electrolyte containing metal ions. This arrangement allows metal electrodeposition to occur simultaneously on both window panes and increases switching speed such that devices switch to similar to 30% transmission in 10 s compared to analogous windows with one working electrode which take 30 s to reach the same transmission value. Windows with two working electrodes switch between clear (similar to 82% transmission at 600 nm) and black (similar to 8% transmission at 600 nm) states within 30 s, making them among the fastest metal-based dynamic windows reported on this scale. Second, we elicit selective metal electrodeposition on Pt nanoparticles that are attached to ITO substrates via a self-assembled monolayer (SAM). By patterning the SAM of Pt nanoparticles, metal electrodeposition can be spatially controlled on both the macroscale and microscale. Taken together, these results demonstrate the versatility of the reversible metal electrodeposition architecture for dynamic windows. (C) The Author(s) 2019. Published by ECS.