Dartmouth Institute for Health Policy and Clinical Practice
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SOUNDBYTES: Device For Recording Sound Waves to Research Activity in a Dental Office
No full textOral health remains a significant public health challenge in the United States, with demand for dental services outpacing availability. This limited access to care leads to a reduced quality of life and increased healthcare costs. Despite the growing need for efficient service delivery, many dental practices struggle to maximize patient capacity due to inefficient scheduling methods that rely on qualitative assessments and manual estimates. In essence, small-scale dental practitioners need a way to schedule procedures based on accurate estimates of procedure durations to make their practices more efficient. To address this issue, our team proposes a HIPAA-compliant device that is able to quantify the duration of specific dental procedures. By leveraging real-time data, this technology enables practitioners to optimize appointment scheduling, minimize downtime, and improve operational efficiency. More accurate scheduling allows dentists to see more patients without compromising care quality, helping expand access to treatment while strengthening the financial sustainability of practices. By streamlining clinical workflows, this solution has the potential to increase efficiency, lower operational costs, and improve patient outcomes, ultimately reducing overall healthcare costs and enhancing access to oral healthcare
Interventional Radiology Wire Management Device
No full textInterventional radiologists and other medical professionals perform a variety of procedures that require the use of guidewires and catheters, but unfortunately OR management of these instruments is challenging. Currently, a bowl with internal ridging holds the wires in a heparinized saline bath. This is frustrating and insufficient, as wire identification, separation, and removal is time consuming and difficult. Our device, engineered in collaboration with Dartmouth Health, has addressed these issues by employing a multi-compartment approach to guidewire and catheter storage. Current storage strategies and saline access are still possible, with an open central compartment. Our design also has a compartment with capacity for up to 7 completely separated and easily identifiable guidewires or catheters. Saline addition in any one compartment will equalize to the entire bowl. A removable lid allows for multidirectional orientation of the bowl based on physician preference, as well as straightforward wire retrieval and ease of wire management
Designing a More Accessible Wheelock Street
No full textThis project proposes new designs of West Wheelock Street - a minor arterial road in Hanover, New Hampshire that experiences heavy pedestrian, bicycle, and vehicular traffic. The guiding objectives of the redesigns are improving the safety of and quality of the experience for pedestrians and cyclists, whose needs have been neglected by traditional transportation engineering design. Three alternative streetscape designs are proposed, guided by the Department of Transportation’s Complete Streets ideology, recommendations from the Hanover Bike Walk Committee, and user feedback from Dartmouth College students and Upper Valley residents. The first alternative centers around pedestrians, the second on cyclists, and the third focuses on traffic calming. In each design, the street’s cross-section is reconfigured by altering the widths and locations of sidewalks, bike lanes, vehicle lanes, and buffers. This is presented visually in the Streetmix software, and is accompanied by design recommendations for intersections, crossings, landscaping, and lighting. Redesigns are analyzed comprehensively to assess their impact on the current transportation landscape and Hanover community. All three improved Level of Traffic Stress ratings for people who bike and walk. Another notable component of the analysis was a traffic model prepared in the discrete event modeling software AnyLogic. The modeling work shows that slowing vehicle speeds and altering intersection characteristics do not worsen current vehiculal backups. Additional components of the holistic design assessment include an economic analysis, potential construction timelines, and a qualitative discussion of a redesign’s impact on Hanover’s sense of place and the character of its community.
Tracked Electric Vehicle to Access Backcountry Ski Trails
No full textLong, low-angle approaches in backcountry skiing substantially limit the terrain that can be accessed in a single day. Snowmobiles remain the primary motorized solution but are difficult to transport and pose needless risk to the user, other recreationists, and the environment. Other options fall short of the portability, cost-effectiveness, or flexibility necessary to solve this problem. To address this gap, we refined a compact, battery-powered electric vehicle to aid skiers in efficiently reaching backcountry trails. Our prototype keeps the backcountry skier on their skis as a wheel behind them propels them forward. The prototype previously developed by our sponsors encountered issues of inadequate torque for some climbs, overheating, and a lack of safety measures. To solve the issue of overheating, we paired a 3kW mid-drive motor with a 2.5:1 gear reduction providing a 40% increase in torque from the previous hub-drive system. We fabricated custom motor and battery mounts to accommodate the motor which also provides more air cooling to resolve overheating. The motor battery combination provides an estimated 19 miles of range on flat ground and 4500 ft. of elevation gain on a sustained 10º slope. Moving to the open source VESC software provides a robust platform for testing drivetrain performance, tuning throttle response, and incorporating a killswitch. This vehicle offers a highly portable alternative to existing snow travel solutions. Future work includes extensive on-snow testing, ergonomic refinements and thorough traction exploration
Evaluating Updated Fentanyl Immunoassays for Loperamide Interference
No full textBackground
Loperamide is a µ-opioid receptor agonist that reduces intestinal peristalsis and is used to treat diarrhea. We previously described significant cross-reactivity of loperamide with 2 fentanyl immunoassays. Since then, new fentanyl immunoassays, including a CLIA-waived point-of-care device, have been approved for clinical use. Methods
We evaluated new fentanyl immunoassays for cross-reactivity to loperamide and its major metabolites, N-desmethyl loperamide (dLop) and N-didesmethyl loperamide (ddLop). Previously characterized assays were tested for cross-reactivity to ddLop, which recently became commercially available. Loperamide, dLop, and ddLop were spiked in drug-free urine for analysis by 5 enzyme immunoassays run on automated chemistry analyzers and one lateral flow assay for the detection of fentanyl. Results
Loperamide and its metabolites produced positive results in 3 fentanyl immunoassays. The Immunalysis HEIA was previously determined to be reactive to both loperamide and dLop, but it was not reactive to ddLop. The Immunalysis SEFRIA was reactive to loperamide, dLop, and ddLop at minimum concentrations of 14.7 mg/L, 13.1 mg/L, and 17.0 mg/L. The Thermo Fisher DRI was previously determined to be reactive to loperamide and dLop, and it was reactive to ddLop at a minimum concentration of 33.1 mg/L. The Abbott iCassette, ARK Fentanyl II, and Lin-Zhi LZI II fentanyl assays showed no cross-reactivity to loperamide or its metabolites. Conclusions
The cross-reactivity of loperamide, dLop, and ddLop in several fentanyl immunoassays has the potential to cause false-positive results during urine drug screening
REPRESENTATION, DYNAMICS AND OPTIMIZATION OF PHYSICAL STRUCTURES
No full textComputational tools play a vital role in structural analysis and design, enabling engineers and researchers to optimize performance, reduce material usage, and explore novel configurations across solids and fluids. Capturing, analyzing, and optimizing these structures while balancing efficiency, stability, and adaptability remains a central challenge. This thesis proposes three complementary methods that advance representation, simulation, and optimization. We present an impulse (gauge) fluid formulation that utilizes the impulse gauge variable to reduce numerical diffusion and better preserve coherent flow features such as vorticity at practical resolutions. We introduce a differentiable Voronoi representation for cellular solids that provides smooth implicit boundaries and natural topology change via seed motions, enabling end-to-end sensitivities for compliance-driven objectives under manufacturability filters. We further develop a reduced-order nonlinear thin-shell topology optimization framework that retains essential geometric nonlinearity while lowering per-iteration analysis cost, delivering accurate adjoint gradients for large-deformation shell design. Together, these methods improve the fidelity and scalability of structure-aware simulation and design in engineering and computer graphics
Beyond Diagnostic Thresholds: Measures of the Maternal Cardiometabolic Health Continuum and their Association with Placental Function
No full textDiabetes and hypertension during pregnancy adversely impact maternal and offspring health. Altered placental function is hypothesized to be involved, but impacts of elevated glucose and blood pressure (BP) within the subclinical range are unknown. The objective of this thesis is to evaluate how elevated glucose and BP, above and below diagnostic thresholds, impact measures of placental development and function including gross morphology (Aim 1), histopathology (Aim 2), and maternal circulating miRNAs (Aim 3), many of which originate in the placenta. Gross morphology and histopathology data from the New Hampshire Birth Cohort Study were used for Aims 1 and 2, and circulating miRNA data from the Maternal And Developmental Risks from Environmental and Social Stressors cohort were used for Aim 3. To measure elevated glucose and BP within the subclinical range, continuous glucose concentrations and longitudinal BP trajectories were evaluated. Diabetes was associated with an earlier delivery and larger birth weight but was not associated with measures of placental gross morphology or histopathology. Participants with type 2 diabetes had lower circulating levels of placenta-specific miRNAs involved in insulin regulation, metabolism, and placental development. In the subclinical range, elevated glucose was associated with earlier delivery, placental histopathological features indicative of delayed maturation, consistent with prior literature for diabetes, and lower levels of miRNAs associated with longer gestational duration. Preeclampsia was associated with lower placental weight, reduced placental efficiency, higher odds of preterm delivery, and lower circulating levels of miRNAs in involved in inflammation, cardiac cell differentiation, and placental function. Conversely, chronic hypertension was associated with larger placental weight and upregulation of a placenta-specific miRNA associated with shorter gestational duration. Elevated BP below diagnostic thresholds was associated with shorter gestation, altered circulating levels of miRNAs involved in placenta function and, paradoxically, higher placental efficiency. Collectively, these findings support that elevated glucose and BP, above and below diagnostic thresholds, are associated with earlier delivery and measures of placental structure, function, and molecular signaling, including markers previously associated with earlier delivery. This research supports the hypothesis that altered placental function may contribute to the adverse effects of elevated glucose and BP, including within the subclinical range
Ecology of Ixodes scapularis Say: Experimental and Observational Studies with Social Perspectives on Ticks and Tick-Borne Diseases
No full textTick-borne diseases are a growing concern globally. Understanding the factors that influence tick ecology and people’s understanding of that ecology is crucial for developing effective tick management and disease prevention strategies. In this work, I investigated fundamental questions about the ecology of a primary vector of medically important pathogens in the United States, the blacklegged tick Ixodes scapularis Say, and identified common misconceptions about ticks and tick-borne diseases on social media. First, I examined the effects of temperature and moisture stress on the movement of adult female I. scapularis in laboratory experiments. Using a Drosophila Activity Monitor, ticks were exposed to controlled temperatures from 10°C to 25°C and relative humidities of 75%, 84%, and 100%. The probability of tick movement responded independently and non-linearly to both temperature and vapor pressure deficit (VPD), with implications for tick activity under natural conditions. Using field observations collected over five years, I then explored how local environmental conditions influence tick host-seeking activity in Hanover, New Hampshire. I. scapularis activity was best predicted by the sampling date, habitat type (forested, edge, or meadow), and morning minimum VPD. Specifically, more host-seeking adult ticks were collected during early spring and fall, in forest and edge habitats, and when morning conditions were wetter. This fine-scale analysis highlights the importance of season- and habitat-specific strategies for reducing disease risk. Lastly, I explored public perceptions and misinformation about ticks on Facebook, recognizing that public education is a vital component of disease prevention. Misinformation was relatively rare – just 17% of 170 public posts and 2483 comments from summer 2021 contained misinformation – and predominantly related to issues with tick biology and ecology. This study underscores the need for targeted public health campaigns to dispel common misconceptions and inform the public accurately about tick prevention and control. Taken together, this work bridges ecological research and its application to public health. By integrating our understanding of the natural world and how it may change as the anthropogenic footprint increases, my work informs more effective tick management practices and public health education efforts, thereby contributing to the reduction of the burden associated with tick-borne diseases
Cell Competition Eliminates Aneuploid Human Pluripotent Stem Cells
No full textAberrant mitotic chromosome segregation results in the generation of cells with aneuploidy, an incorrect number of chromosomes. Aneuploidy can compromise the viability of the developing embryo and is the leading cause of pregnancy loss, failed embryo implantation, and congenital birth defects. Yet, widescale analysis of human embryos from in vitro fertilization (IVF) clinics suggests that aneuploidy is common, with upwards of 70% of preimplantation embryos being aneuploid.
Mitotic chromosome missegregation during post-zygotic development results in mosaic embryos made up of both diploid and aneuploid cells. Strikingly, upon transplant for pregnancy, mosaic embryos have been reported to result in healthy birth without genetic abnormalities. A genetically normal offspring from an embryo comprised of aneuploid cells causes a discrepancy in knowledge, as it is well established that aneuploidy is detrimental to embryonic development. Consequently, the cellular processes required for proper development of a mosaic embryo are not fully understood. Human pluripotent stem cells (hPSCs) also exhibit high rates of erroneous chromosome missegregation and aneuploidy during prolonged propagation in vitro, suggesting that these are both inherent features of embryonic and pluripotent stem cells. My thesis work aims to uncover both the causes and consequences of aneuploidy in pluripotent stem cell populations.
In Chapter 2, I contribute to efforts to define hPSC mitotic chromosome fidelity. Our results demonstrate that hPSCs inherently possess a low mitotic fidelity which is directly correlated with a cell’s developmental potential. In Chapter 3, I investigate the immediate consequences of chromosome missegregation and aneuploidy in hPSCs and observe the long-term fate of aneuploid cells in mosaic hPSC populations. I find that hPSCs do not elicit a cell autonomous response to and are inherently tolerant of aneuploidy. Furthermore, my data demonstrates that cell competition eliminates aneuploid hPSCs when neighboring more fit diploid hPSCs.
Importantly, our work finds that a pluripotent state confers a low fidelity of chromosome segregation. Moreover, my research reveals that hPSCs are tolerant of aneuploidy, but genomic integrity is preserved through the elimination of aneuploid cells in mosaic environments by cell competition. My thesis provides new insights into the biology of early embryonic cells and hPSCs
