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Universal Robotic End Effector Design and Granular Material Selection for FANUC Collaborative Robot Implementation
Get PDFThe objective of this research was to create a universal robotic end effector also known as a jamming gripper and test the effectiveness of coffee grounds vs. kinetic sand as the granular material used in the end effector. The apparatus used was a system containing an Arduino UNO, a 12-volt vacuum pump, an h-bridge, a solenoid valve, and the jamming gripper itself. An assortment of objects was used to see how well the gripper could pick up objects of different sizes, shapes, and weights. After various trials, the coffee grounds yielded much better results than the kinetic sand. The kinetic sand adhered too strongly to itself and lacked the soft-to-hard phase transition that the coffee grounds possess. This phase transition allows the coffee grounds to conform to an object and grip onto it when necessary while also separating adequately when the object needs to be released. The eventual goal is to create a fully autonomous universal robotic end effector and collaborative robot system that can pick up and place delicate and uniquely shaped objects
Incitement, Enthusiasm, and the Dangers of Negligent Protest
Get PDFThis Article explores the murky line between protected speech and assembly on the one hand, and harmful incitement on the other. On the occasion of the 100th anniversary of Oliver Wendell Holmes’s dissent in Gitlow v. New York, it explores Holmes’s famous dictum that “every idea is an incitement” as a conceptual starting point. By analyzing the relational and temporal dynamics between speaker and listener, the Article highlights how meaning and effect are often shaped by the listener’s agency and other circumstances beyond the control of the speaker. Two contemporary cases illustrate these dynamics. The first is the Fifth Circuit controversial decision in Mckesson v. Doe, which asserted that protest organizers might be civilly liable for the violent actions of others under a “negligent protest” theory. The second is President Donald Trump’s words on January 6, 2021, and their relationship to the ensuing violence at the Capitol. In both cases, the Article challenges the adequacy of foreseeability alone as a basis for liability, particularly given the First Amendment interests at stake. The Article proposes a potential middle ground: applying a recklessness standard to protest related liability. Drawing from the Model Penal Code and recent Supreme Court decisions like Counterman v. Colorado, this framework would require subjective awareness of a substantial and unjustifiable risk, offering a more constitutionally sound alternative to negligence theory
Investigating the interplay of genetic factors and viral infections in type 1 diabetes pathogenesis
No full textType 1 diabetes (T1D) is an autoimmune disease characterized by hyperglycemia due to the loss of insulin-producing pancreatic β cells. With over 70 associated genetic loci identified, T1D is known to have a strong genetic component, but a high discordance rate in identical twins suggests a critical role for environmental factors. Coxsackievirus B (CVB) infection has long been implicated as a potential environmental trigger for T1D. Meanwhile, genome-wide association studies have identified IFIH1, a gene that encodes the viral sensor MDA5, as a key susceptibility locus. Notably, different single nucleotide polymorphisms (SNPs) within IFIH1 have been associated with either increased risk or protection. However, due to the scarcity of high-quality cadaveric islets of Langerhans from T1D patients, their heterogeneous nature, and technological limitations, the interplay between these genetic factors and environmental stressors in a human pancreatic context has been difficult to study. This dissertation addresses these critical knowledge gaps by investigating the cellular and genetic factors that govern islet response to stress using advanced human islet models and single-cell sequencing technologies. The first chapter provides a general overview of T1D as an autoimmune disease, key immune-associated T1D susceptibility genes, enteroviral infection as a potential environmental trigger, and the use of human pluripotent stem cells (hPSCs) for disease modeling. In the second chapter, we hypothesized that CVB3 infection induces unique cell-type-specific transcriptional responses in primary human islets. We used single-cell RNA sequencing (scRNA-seq) to show that CVB3 infects all cell types within primary human islets at a similar rate, contrary to prior claims based on viral protein staining. We found that insulin-secreting β, glucagon-secreting α, and ductal cells exhibit the most robust transcriptional responses to viral infection, with ductal cells showing the strongest interferon-stimulated response. CVB3 infection also induced mitochondrial dysfunction, with differential effects on mitochondrial size in β and α cells. Our dataset also identified the long non-coding RNA, MIR7-3HG, as a key regulator of viral titer, apoptosis, and autophagy upon genetic knockdown in stem cell-derived islets (SC-islets). The third chapter of this thesis investigated how specific IFIH1 SNPs impact islet health and stress response. We hypothesized that the protective MDA5627* variant protects islet cells against stress-mediated dysfunction, identity loss, and cell death compared to the at-risk MDA5946T variant. Using SC-islets generated from CRISPR-Cas9-edited hPSCs derived from a T1D patient, our scRNA-seq analysis demonstrated unique, cell-type-specific transcriptional responses to inflammatory and viral stress that varied across the MDA5 variants. Our data showed the MDA5627* variant dampened the stress-mediated immune response and mitochondrial dysfunction, while also improving insulin secretion, reducing apoptosis rates, and lowering viral genome expression in SC-islets. Overall, this dissertation provides a comprehensive overview of cell-specific responses in both primary human islets and SC-islets following viral and inflammatory stress. We characterized the roles of key candidate genes and clinically relevant variants in promoting islet health. The insights gained from these studies broaden our understanding of the connection between genetic variation, environmental factors, and islet health in humans, providing a crucial foundation for developing strategies to prevent or delay T1D initiation and progression in genetically susceptible individuals
The Transformation of Isoxaflutole in Natural and Engineered Systems
No full textAgrochemicals are a potential source of contamination in water resources. Whether an agrochemical poses an ecological or human health risk depends on its environmental concentration, which is a function of the rate of degradation, and its toxicity. One category of agrochemicals for which there has been increased use observed, potentially leading to increased environmental concentrations, are herbicides that are approved for use on commercially released genetically modified (GM) crops with the associated herbicide-tolerance traits. The GM tolerance trait for the herbicide isoxaflutole was introduced in commercially available crops starting in 2020. The addition of isoxaflutole-tolerance traits to GM crops has been identified by the US Environmental Protection Agency (EPA) as a beneficial tool to combat rising resistance to herbicides among weeds, especially for herbicides like glyphosate that have been used on GM glyphosate-tolerant crops for decades. The potential rise in the use of isoxaflutole due to the introduction of GM crops has resulted in increased concern of the fate of isoxaflutole post-application to fields. Paired with the high toxicity of isoxaflutole and its active form and hydrolysis product, diketonitrile, the transformation of both isoxaflutole and diketonitrile in the environment can determine the impact of applied isoxaflutole. The first objective of this dissertation was to investigate the persistence and transformation of diketonitrile present in drinking water sources in comparison to the previously demonstrated minimal reactivity of isoxaflutole with the drinking water oxidant, free chlorine. I found that diketonitrile reacts more rapidly with free chlorine than monochloramine, which are common oxidants used in drinking water treatment, but result in the formation of the same products (e.g., disinfection byproducts). I demonstrated that diketonitrile is a uniquely high-yield precursor for a highly toxic nitrogenous disinfection byproduct, dichloroacetonitrile (DCAN) in the presence of both oxidants. Using both kinetic and product data at multiple pH conditions, I proposed an updated reaction mechanism for the reaction of diketonitrile with both free chlorine and monochloramine, which is consistent with the high yield of DCAN. From this first objective, I concluded that the speciation of isoxaflutole and diketonitrile in drinking water sources will affect the way in which applied isoxaflutole poses a threat to human health. The second objective of this dissertation was to investigate the hydrolysis of isoxaflutole to diketonitrile to improve the prediction of the rate of hydrolysis in natural water sources. I demonstrated that isoxaflutole hydrolysis is particularly sensitive to catalysis by weak bases used in buffers in laboratory experiments to estimate hydrolysis in natural waters sources. I obtained the bimolecular rate constants for isoxaflutole hydrolysis with bases commonly present in laboratory buffers (i.e., carbonates, phosphates) relative to hydroxide, which is typically assumed to dominate the rate of base-catalyzed hydrolysis. Using the bimolecular rate constants I obtained, I constructed a linear free energy relationship, the Brønsted relationship, to assess the sensitivity of the reaction to base strength. I determined that rate constants previously measured and used in risk assessments to predict the rate of transformation in the environment overpredict the rate of hydrolysis, particularly near neutral pH. Lastly, I demonstrated that the bimolecular rate constants I obtained can be used to more accurately predict hydrolysis in natural water sources. The third objective of this dissertation was to investigate whether overprediction of hydrolysis occurs more widely (e.g., contaminants other than isoxaflutole). I conducted a review of literature to assess the typical conditions at which hydrolysis is measured in the laboratory to assess hydrolysis in real water sources (e.g., groundwater, surface water, drinking water treatment, agricultural water). I found that since 2014 there has been a trend of increasing reliance on the EPA and/or Organisation for Economic Co-operation and Development (OECD) guidelines for assessing hydrolysis, both of which cite a foundational publication from Mabey & Mill (1978). Notably, Mabey & Mill estimated that buffer effects are negligible within concentrations of 10 mM. I also found that only a small fraction of studies from 1971 to 2023 measured hydrolysis in real water sources. Among these studies there was a trend of faster hydrolysis in laboratory water, although the assumption that buffer effects were negligible led to most studies to look for causes of inhibition in the real water sample rather than sources of catalysis in the laboratory water. Using two linear free energy relationships, the Brønsted and Swain-Scott relationship, I demonstrated that consistent with our findings for isoxaflutole hydrolysis, buffer concentrations lower than 1 mM have the capacity to significantly contribute to the rate of hydrolysis. Based on these results, I provided updated recommendations for assessing the hydrolysis of contaminants in the laboratory that can be more accurately translated to real water sources. The fourth objective of this dissertation was to develop a method that would enable the quantification of isoxaflutole and diketonitrile in future field campaigns. While occurrence studies for isoxaflutole and its products have been conducted since the early 2000s at a variety of sampling locations, the effect that the introduction of GM isoxaflutole-tolerant crops have on the occurrence of isoxaflutole and diketonitrile in Midwestern water sources has not been investigated. In this objective, I outlined a field campaign to achieve this goal. Then, I determined the optimal method for the concentration of samples post solid-phase extraction of natural water samples. Lastly, I established a liquid-chromatography mass-spectrometry/mass-spectrometry (LC-MS/MS) method to quantify isoxaflutole and its products after sample processing. Overall, this dissertation (1) demonstrates that isoxaflutole, which converts to diketonitrile in water sources used for drinking water, poses a unique threat as a high-yield precursor for a toxic disinfection byproduct, (2) identifies the importance of assessing the contributions of weak bases present in buffers used to measure hydrolysis in laboratory conditions to prevent overestimation of the rate of hydrolysis in natural waters, not only for isoxaflutole but for any contaminant whose risk characterization is dependent in part on the rate of hydrolysis, and (3) establishes methodology required to assess the effects of the introduction of GM isoxaflutole-tolerant crops on the occurrence in real water sources. Thus, this dissertation contributes to an advanced and improved understanding of the transformation of both isoxaflutole and diketonitrile in natural and engineered water systems
The Experience of Administrative Burdens in SNAP and Medicaid: New Evidence from a Nationally Representative Survey of Low-Wage Workers
No full textWhen functioning correctly, the U.S. social safety net ensures that everyone can reach a basic standard of living, regardless of economic circumstances, and provides financial support to help families who have fallen on hard times due to job losses or other adverse life events. However, the programs often have complex rules around eligibility, documentation requirements, and compliance. Those features and negative experiences with program staff impose psychological costs—collectively referred to as administrative burdens—that can make enrolling and staying in the programs difficult for many families. Drawing upon data from the Workforce Economic Inclusion and Mobility Survey of a nationally representative sample of 2,511 low-wage U.S. workers with incomes below 250% of the federal poverty line, this brief builds (a) presents a new measure of administrative burden that captures multiple dimensions of learning, compliance, and psychological burdens; (b) examines differences in those burdens between the Supplemental Nutrition Assistance Program and Medicaid; (c) identifies who reports experiencing these burdens; and (d) investigates the correlation between the experience of burden in these programs and measures of health-related hardship
Job-Training Programs for Older Americans
No full textThe traditional notion of retirement—stopping work completely to focus on personal pursuits in one’s golden years—is not guaranteed. In the United States, three in four adults plan to work past age 65. Many older adults continue working due to financial necessity, including rising healthcare costs, insufficient retirement savings, and gaps in pension coverage. Low-wage workers, in particular, may struggle to retire at all, forced to keep working to afford basic necessities such as housing and food. Older adults also seek employment for their personal health and well-being, such as staying physically and mentally active, finding a sense of purpose, and maintaining social connections
Living Longer, Working Longer
No full textAccording to the Pew Research Center, nearly one-in-five Americans ages 65 and older (19%) were employed in 2023, a rate nearly twice that from 35 years ago. They’re also working more hours, on average, than in the recent past. In fact, more than three-in-five older workers (62%) work full time, an increase from the 47% working full time in 1987. Older workers today are also more educated and are more likely to be receiving employer-sponsored benefits, such as retirement savings plans and health insurance, than in earlier decades. While only 4% of the entire labor force was made up of people age 65+ in 2009, the share is expected to more than double, to 10%, by 2029
Separation-of-Powers Lochnerism
No full textOne hundred and twenty years ago, the Supreme Court handed down one of the single most notorious opinions ever rendered, striking down a New York labor law for violating a right to contract found nowhere in the text of the Constitution. The era of Lochner v. NY (1905) is well past us, but not the judicial impulses that gave rise to the case. With a new champion in the Roberts Court, Lochnerism is alive and well, deployed in a new context to redefine the relationships between the President, Congress, federal agencies, and the courts. Bringing together two lines of case-law-on the President and the agencies-this Article shows how the Roberts Court is now doing for the separation of powers, what the Lochner Court did for rights. In the first, the Court identifies core presidential (super-)powers and bars Congress from regulating these by statute. In the second, it crafts unwritten principles that defeat agency action: the rule that Congress must give a clear statement when it delegates major authority, or that deference to agencies violates judicial independence, are two examples. Taken together, the two lines of cases make the separation of powers into a collection of judge-made rules no other branch can change, arrived at by judges who disregard plain text for higher-law values they alone can see and articulate. One particularly salient consequence has been the aggrandizement of the presidency, now put in full relief by the unprecedented barrage of executive orders issued by the second Trump presidency, many of questionable legal grounding. During the \u2723-\u2724 term, the Court\u27s landmark rulings on presidential immunity and the federal agencies each garnered significant attention. But viewing them through the lens of this new separation-of-powers Lochnerism reveals these to be part of the same judicial project, a judge-led revolution decades in the making. Our Constitution creates three branches of power and gives each tools to mutually check and balance the others. Separation-of-Powers Lochnerism distorts this ideal into a judge-made constitutional order requiring interbranch isolation (except on the part of the judiciary), with the roles of Congress, the President, and the agencies increasingly being defined by the Supreme Court according to higher-law principles of its own making. This Article demonstrates that this scheme is both ahistorical and dangerous, threatening to upend our tripartite system of government
Policy Design for Multiple Funding Flows Into Trump Accounts
No full textThe law creating the new Trump Accounts explicitly authorizes employers to provide deposits matching contributions that their employees make to the accounts and also authorizes contributions by philanthropic organizations. Both features are essential for building substantial lifetime assets for America’s children. Implementing them successfully – and ensuring that the funds reach every eligible child efficiently – will require an effective policy platform for routing, verifying, and reporting on third-party contributions. This brief discusses why traditional retail IRAs cannot support matching contributions and how to build a policy platform capable of accommodating multiple contribution streams
When Engagement Meets Distraction: The Effects of Multitasking Types on Learning from Video Lectures
No full textStudents often multitask with lecture-relevant (e.g., note-taking) and lecture-irrelevant (e.g., texting) secondary tasks during lectures and such behavior tends to be more common in asynchronous than synchronous settings. Two experiments investigated the combined and comparative effects of lecture-relevant and lecture-irrelevant secondary tasks on attention to and retention of a geology video lecture in a simulated asynchronous setting. Participants were randomly assigned to one of four conditions: lecture-only, lecture-relevant multitasking (i.e., taking notes during the lecture), lecture-irrelevant multitasking (i.e., completing a survey in Experiment 1 or instant messaging in Experiment 2 during the lecture), or hybrid multitasking (both note-taking and survey or instant messaging). Participants completed several attention checks during the lecture and then took a retention test, which assessed their knowledge of facts and concepts presented in the lecture. Results from both experiments showed a pattern that indicates that participants who engaged in lecture-relevant multitasking demonstrated the most attention and retention in both factual and conceptual knowledge types, while those who engaged in lecture-irrelevant multitasking showed the least attention and retention. Participants who only watched the lecture (lecture-only) or engaged in hybrid multitasking showed moderate attention and retention. Moreover, the benefits of lecture-relevant multitasking and the detriments of lecture-irrelevant multitasking appeared to be similar for the acquisition of both factual and conceptual knowledge. Participants also demonstrated various multitasking strategies, including serial, concurrent, and mixed strategies. Findings are discussed from the perspectives of cognitive load, attention, and generative processing theories