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Half-Sandwich Ru(II) Complexes Featuring Metal-Centered Chirality: Configurational Stabilization by Ligand Design, Preparation via Kinetic Resolution, and Application in Asymmetric Catalysis
No full textWhile it is well established that half-sandwich Ru(II) complexes possess metal-centered chirality, effective strategies to leverage their metal-centered chirality toward asymmetric synthesis have been challenging due to the configurational lability of the metal stereocenters. The metal-centered chirality is typically mediated by enantiopure ligands, which occupy a relatively narrow chemical space compared to their achiral counterparts. We demonstrate that achiral ligands can be used to access chiral-at-ruthenium half-sandwich complexes with exceptionally high configurational stability. Key to success is the introduction of a rigid bidentate ligand with a minimized dihedral angle between the pyridyl and phenolic moieties, which proved effective for preventing racemization. Computational studies revealed the energetic factors contributing to the exceptional configurational stability enabled by the rigid and planar structure of the successful ligand design. These optically active chiral-at-ruthenium complexes incorporating aldehyde moieties were obtained by NHC-catalyzed kinetic resolution with excellent selectivities (s-factor up to \u3e200, ee up to 99%). We further demonstrate that they are highly effective chiral aldehyde catalysts for the asymmetric 1,6-conjugate addition of glycine ester and para-quinone methide
The Symbolism of the Andean Condor: Its Meaning in the Indigenous Cosmology, Culture, and National Identity of Ecuador and the Andean Region
No full textEste proyecto se enfoca en el tema del simbolismo, significado y conservación del cóndor andino en la región andina, con un énfasis en Ecuador. Las encuestas, observaciones, entrevistas, y fuentes secundarias fueron utilizados para registrar información sobre la relevancia y contexto del cóndor como un símbolo andino. La investigación reveló que el símbolo del cóndor andino juega un rol significativo en la identidad nacional, la cosmovisión andina, y la representación de liberación del colonialismo. Discutió las actitudes populares hacia la disminución de la población de cóndores andinos. La monografía disputó la minería, la caza ilegal, y la comodificación de la espiritualidad como algunos asuntos económicos, sociales y ambientales relevantes de la población baja de cóndores. Termina con una llamada por la preservación del patrimonio cultural y ecológico y una idea para investigación siguiente: la viabilidad de un modelo biocultural de conservación.
This project focuses on the theme of symbolism, meaning and conservation of the Andean condor in the Andean region, with an emphasis on Ecuador. Surveys, observations, interviews, and secondary sources were used to record information about the relevance and context of the condor as an Andean symbol. The research revealed that the symbol of the Andean condor plays a significant role in national identity, the Andean indigenous cosmologies, and a representation of liberation from colonialism. Carter-Smith discusses popular attitudes toward the decline of the population of Andean condors. They explore mining, illegal hunting, and the commodification of spirituality as some relevant economic, social and environmental issues contributing to the critically low population of Andean condors. The project ends with a call for the preservation of cultural and ecological heritage and an idea for further research: exploring the feasibility of a biocultural model of conservation
Exploring the role of alternative polyadenylation and splicing during zebrafish embryogenesis
No full textDuring transcription of a gene, one of the final steps required to make an mRNA is known as polyadenylation, which involves the addition of a polyA tail, or a stretch of adenosines that help promote translation and protect the mRNA from damage in the cytoplasm. For many genes, addition of this tail can occur at one of multiple possible locations in the 3’ untranslated region (3’UTR). Alternative polyadenylation involves the production of different mRNA sequences with different 3\u27UTR lengths, which contain binding sites for proteins and miRNAs that influence the stability or localization of the mRNA. In our lab, we use zebrafish as a model organism to study how alternative polyadenylation influences the determination of the identities and functions of cells. The genes we explore are: myo1b, elavl1a, and the ZEB1 family(zeb1a & zeb1b), each playing some role in cell division or differentiation during embryonic development. Though the expression of our genes of interest have been assessed, the functions of these unique isoforms have not previously been described. So far, we have used qPCR to quantitatively investigate the changes of gene expression across development. In our preliminary work, myo1b and zeb1a short isoforms were most highly expressed at 48 hours post-fertilization, elavl1a short isoform expressed more than the long consistently. We also hope to use in situ hybridization to analyze spatial expression of our isoforms of interest. Ultimately, we aim to characterize differential expression between different isoforms across stages of embryogenesis to better understand the impact of alternative polyadenylation during development
Mālama I Ka Loʻi Kalo: Kānaka Hawaiʻi Health and Wellbeing Within the Continental U.S. Hawaiian Diaspora
No full textAmong diasporic Kānaka Hawaiʻi born and raised in the continental United States, many experience isolation and imposter syndrome about Hawaiian heritage, due to a lack of accessibility to traditional practices, cultural education and ways of knowing; and isolation from the Hawaiian community. While not unique to Diasporic Kānaka Hawaiʻi, many of these issues occur more prominently as a result of migration away from familial, cultural, spiritual, and educational support networks, and increased proximity to U.S. settler culture. In the Hawaiian health and wellbeing model titled, The Ahupuaʻa Model (Daniels et al. 2022), these support networks are supposed to serve as “protective factors” to the trauma of colonization, systemic poverty, and violence which determine Hawaiian health and wellbeing. In addition, protective factors are meant to uplift Hawaiian conceptions of health, including interconnected spiritual, cultural, mental, familial, and intergenerational. However, access to protective factors in the Ahupuaʻa Model are much more attainable and realistic in Hawaiʻi than in the continental U.S. Therefore, after identifying these distinct Hawaiian wellbeing issues linked with migration, the question becomes: how does the Ahupuaʻa Model shift when factoring in the Diasporic experience? In assessing this question, we can begin looking forward to protective factor development: what protective factors have already developed in the Diaspora? What practices do we have to implement to sustainably create and support protective factors that address these Diasporic issues? By addressing these issues, I hope to promote the creation of wellbeing support and resources for Kānaka Hawaiʻi living in the Diaspora
The Impact of Knee Osteoarthritis Distribution and Presence of Total Knee Replacement on the Effectiveness of Genicular Nerve Radiofrequency Ablation for the Treatment of Knee Pain
No full textThe Impact of Cervical Transforaminal Epidural Steroid Injections on Cervical Radiculopathy in the Setting of Cervical Foraminal Stenosis Versus Cervical Disc Herniation
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Sedimentation Evolution of Dredged Estuary
No full textEstuarine sediment infilling is an emerging area of study due to sea-level rise; managed retreat and wetland restoration offer human-supported solutions. The Mink Meadows “Yacht Basin” on Martha’s Vineyard, created by dredging in 1963, provides an unlikely case study for the evolution of a human-constructed wetland over time. Sediment core samples of the basin and surrounding marshes were measured for fallout radionuclides 137Cs and excess 210Pb (210Pbex) to determine approximate amount and rate of sediment accumulation. Preliminary 210Pbex values and core analysis indicate quick initial sedimentation after dredging, followed by a steep decline in accumulation. Though near-constant 210Pbex concentrations in two lagoon cores suggest accelerating sedimentation rates, rates are not fast enough to fill significant portions of the lagoon before 2050; accounting for sea-level rise pushes the infill date estimate later. Approximately 40-48 cm of sediment have accumulated since dredging. Marsh cores are currently being analyzed for rate of sedimentation using 210Pbex concentrations to determine whether the surrounding marshes are a source of accumulating sediment. Tidal data will constrain saline-mobile 137Cs for more-precise dating. Moderately high LOI drops off sharply at the backhoe facies, suggesting heavily organic initial sediment followed by limited organic material. LOI core analysis is ongoing. Due to fluctuating LOI data, sediment source remains a question; SEM/XRD analyses will help further determine sediment composition. Current data show leveling similar to non-anthropogenic estuaries, suggesting successful geomorphologic stabilization. Evaluating the success and evolution of this constructed wetland will allow for better understanding of future wetland remediation efforts
