Showing 21 - 30 of 67 Items
Reactions Responsible for Aging in Wood-Based Pyrolysis Oil: Synthesis and Characterization of a Coniferyl Alcohol Dimer
Date: 2021-01-01
Creator: Alejandro Garcia
Access: Open access
- The negative environmental impact and the diminishing supply of fossil fuels demand a renewable alternative. Pyrolysis oils produced from the decomposition of biomass, like wood, are a potential fuel substitute for energy production and a feedstock alternative for manufacturing value-added chemicals. The possibilities offered by pyrolysis oils are offset by oil instability. The oils contain reactive compounds, such as small aldehydes, conjugated aromatics, and acids that over time react and produce higher molecular mass products. This instability manifests as an increase in viscosity by a process referred to as aging. One chemical component, coniferyl alcohol, is proposed to react with formaldehyde under the acidic oil conditions to produce a dimer. In our lab, researchers have detected the coniferyl alcohol dimer in authentic oil samples and have simulated the reaction under conditions that removes the complexity of the pyrolysis oil matrix. This study focused on the synthesis, isolation, and characterization of the dimer structure by employing NMR analysis. GC/MS analysis of a successful synthesis of the dimer showed multiple dimers were produced, but there was one principal product. The NMR analysis of this dimer was used to elucidate the geometry, providing evidence that the product has E stereochemistry for the double bond and trans stereochemistry in the acetal ring. Confirmation of the principal structure provides support for the dimerization mechanism and will allow for future research to address instability of pyrolysis oils.
The Roles of ROG1, REM1, and REM2 in a WAK Mediated Pectin Response Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2015-05-01
Creator: Joshua A Benton
Access: Access restricted to the Bowdoin Community
Role of Polycomb group proteins in regulation of eyes absent gene expression in Drosophila melanogaster This record is embargoed.
- Embargo End Date: 2027-05-16
Date: 2024-01-01
Creator: Joanne Du
Access: Embargoed
Investigating the effect of Fuc-O-NAP on the glycosylation of Helicobacter pylori Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2024-01-01
Creator: Panhasith Ung
Access: Access restricted to the Bowdoin Community
Examining the role of GRP and LIK1 in Wall Associated Kinase (WAK) perception of pectin in the plant cell wall
Date: 2017-01-01
Creator: Jack Ryan Mitchell
Access: Open access
- Wall associated kinases (WAKs) are cell membrane bound receptor kinases that bind pectin and pectin fragments (OGs).The binding of WAKs to pectin sends a growth signal required for cell elongation and plant development. WAKs bind OGs with higher affinity than native pectin and instead activate a stress response. Glycine rich proteins (GRPs) are secreted cell wall proteins of unknown function. Seven GRPs with 65% sequence similarity are coded on a 90kb locus of Arabidopsis chromosome 2. GRP3 and WAK1 have been shown to bind in vitro, but single null mutations have no discernible phenotype, suggesting that the GRPs are redundant. Low recombination frequency has made multiple mutations difficult to achieve, but in this thesis, CRISPR/Cas9 technology was used to induce deletions of the GRP locus. The promoters pYAO and pICU2 drove Cas9 expression in transformed Arabidopsis plants. The presence of a deletion and Cas9 were detected by PCR. While somatic mutations were induced, there was no inheritance of the GRP deletion, indicating that pYAO and pICU2 do not drive Cas9 to induce deletions in progenitor cells. LIK1 is a CERK1 interacting kinase implicated in mediating response to various microbe associated molecular patterns (MAMP) such as chitin, flagellin, and peptidoglycans. LIK1 exhibits a drastic increase in phosphorylation in response to OG treatment, making it a candidate for a co-receptor to WAK. T-DNA insertions to the 5’UTR of LIK1 were used to examine the effect of a lik1 mutation on the OG induced stress response. lik1/lik1 mutant seedlings were grown in the presence and absence of OGs, and RNA was isolated. qPCR was used on cDNA to examine FADLOX expression, a reporter for the transcriptional response to OGs. The lik1/lik1 mutant caused a reduction in the OG induced transcriptional response. However, increased LIK1 expression was associated with the T-DNA insertion indicating that LIK1 inhibits the WAK stress response pathway. Understanding the roles of GRP and LIK1 in moderating WAK mediated pathogenic response in Arabidopsis will enable a better understanding of plant resistance to pathogen invasion in the greater plant kingdom.
Characterization of an Arabidopsis thaliana Adhesion Mutant This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Jacob Dexter-Meldrum
Access: Embargoed
Functionality of Candida albicans She3 in the mRNA transport of Saccharomyces cerevisiae Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Sheikh Omar Kunjo
Access: Access restricted to the Bowdoin Community
Binding Energy Determination of CO2 Adsorption in MOF-74 with Diffusion Monte Carlo This record is embargoed.
- Embargo End Date: 2027-05-19
Date: 2022-01-01
Creator: Yucheng Hua
Access: Embargoed
Characterization of Bacterial Glycosylation Pathways with Fluorescent Monosaccharide Probes Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Lucas John DiCerbo
Access: Access restricted to the Bowdoin Community
Physiological responses of the American lobster cardiovascular system to neuropeptide SGRNFLRFamide (SGRN)
Date: 2024-01-01
Creator: Andre Eden
Access: Open access
- During every second of a human’s life, the cardiovascular system is modulated by factors both intrinsic and extrinsic to the physiology of the heart. We can uncover new insights regarding the nature of our system through investigations of similar systems in other model species. One example materializes itself in the form of the American Lobster (Homarus americanus) whose single-chambered heart finds resemblance to the function and anatomy to that of humans. The lobster heart is powered by the cardiac ganglion (CG), a group of neurons that drive contractions of surrounding heart muscles, known as the myocardium. Both the CG and myocardium work in a feedback loop, with both intrinsic (afterload and preload) and extrinsic (temperature and neuropeptides) factors affecting cardiac output (CO) or the overall ability of the heart to carry out its primary function of nutrient distribution. In this paper, we examine how the addition of these factors into in vitro whole heart preparations affect CO and other associated variables. From experimentation, we conclude that the neuropeptide SGRNFLRFamide (SGRN) increases the heartbeat frequency and the active force exerted by the heart. We also conclude that increases in temperature decrease CO as higher temperatures decrease heartbeat frequency and the active force exerted by the heart. Lastly, we conclude that the effect of preload and afterload combined produce more robust effects on the CO and active force of the heart, potentially painting a better picture of what may happen in vivo.