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Volume 1 2018

Volume 1 2018

Subthalamic Nucleus Deep Brain Stimulation Parameter Optimization and Motor Outcome Trajectories in Advanced Parkinson's Disease: A 5-Year Longitudinal Study

Miriam T. Schulz; Kwame A. Asante; Renata P. Oliveira

This study investigates long-term motor outcome trajectories and stimulation parameter evolution in STN-DBS for advanced Parkinson's disease over 5 years with systematic programming optimization within the context of movement disorders neurology and clinical neuroscience, an area of growing scientific importance given its implications for DBS programming optimization frameworks, disease progression monitoring, and patient counseling for long-term surgical expectations. Using prospective cohort with blinded UPDRS-III off-medication/on-stimulation assessment at 6-month intervals with matched programming optimization protocol across 3 centers, we examine STN stimulation inhibiting subthalamic overactivity in basal ganglia-thalamo-cortical loop, reducing motor symptoms with long-term medication reduction, while disease progression drives progressive stimulation amplitude requirements in 184 advanced PD patients (bilateral STN-DBS, disease duration 8-22 years at implant) from 3 movement disorders centers with 5-year follow-up (mean 4.8 years) drawn from 3 U.S. movement disorders centers (Ridgecrest, Lakewood, Northshore) with centralized programming protocol and blinded annual UPDRS-III assessments. Results indicate that STN-DBS maintains 44.2% mean UPDRS-III improvement at year 5 versus pre-surgical baseline on-medication score, but stimulation OFF score worsens by 28.4% from year 1 to year 5, reflecting ongoing neurodegeneration independent of stimulation benefit (p < 0.001), with 44.2% UPDRS-III improvement maintained at year 5; 28.4% stim-OFF worsening indicating disease progression as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to movement disorders neurology and clinical neuroscience and carry actionable implications for the design of programs and policies targeting DBS programming optimization frameworks, disease progression monitoring, and patient counseling for long-term surgical expectations.

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Section 404 Wetland Permit Compliance and Compensatory Mitigation Effectiveness: A 15-Year Analysis of 4,284 Clean Water Act Permits in the Southeastern United States

Beatrice N. Okafor; William T. Harrington; Mei-Xia P. Leung

This study investigates Section 404 Clean Water Act permit compliance rates and compensatory wetland mitigation effectiveness in the southeastern United States from 2002-2017 within the context of environmental law and wetland ecology, an area of growing scientific importance given its implications for Army Corps mitigation policy reform, mitigation banking regulatory incentives, and Clean Water Act enforcement prioritization. Using retrospective analysis of Corps permit records linked to mitigation bank, in-lieu fee, and permittee-responsible mitigation site compliance monitoring reports, we examine permit compliance degradation arising from inadequate monitoring, enforcement resource constraints, and permittee-responsible mitigation site abandonment post-permit closure in 4,284 Section 404 individual permits with required compensatory mitigation from 3 Army Corps Districts (Wilmington, Savannah, Jacksonville) issued 2002-2017 drawn from Wilmington, Savannah, and Jacksonville U.S. Army Corps of Engineers Districts covering North Carolina, South Carolina, Georgia, and Florida. Results indicate that overall permit compliance is 64.2% across 4,284 permits with mitigation bank permits showing significantly higher compliance (84.2%) than permittee-responsible mitigation (48.4%); ecological success rate (achieving hydrology and vegetation targets) is 58.4% across all mitigation types (p < 0.001), with 64.2% overall compliance; 84.2% bank vs. 48.4% permittee-responsible as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to environmental law and wetland ecology and carry actionable implications for the design of programs and policies targeting Army Corps mitigation policy reform, mitigation banking regulatory incentives, and Clean Water Act enforcement prioritization.

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CYP2D6 Metabolizer Phenotype and Tamoxifen Endoxifen Plasma Concentrations in Breast Cancer: Clinical Impact on Recurrence-Free Survival in 2,184 Patients

Yuki M. Tanaka; Priya N. Anand; David T. Morrison

This study investigates association between CYP2D6 metabolizer phenotype, steady-state endoxifen plasma concentration, and 5-year recurrence-free survival in ER+ breast cancer patients receiving adjuvant tamoxifen within the context of pharmacogenomics and oncology, an area of growing scientific importance given its implications for CYP2D6 pretreatment genotyping guidelines, endoxifen-guided tamoxifen dose adjustment, and extended adjuvant therapy decision support. Using prospective pharmacogenomic cohort study with CYP2D6 star-allele genotyping, mass spectrometry endoxifen quantification, and 5-year recurrence-free survival analysis by Cox regression, we examine CYP2D6 enzymatic activity converting tamoxifen to active metabolite endoxifen, with poor metabolizer phenotype reducing endoxifen concentrations below the 16 nM therapeutic threshold and impairing ER antagonism in 2,184 ER+ breast cancer patients (stage I-III) from 8 oncology centers genotyped for CYP2D6 and followed for 5 years after adjuvant tamoxifen initiation drawn from 8 NCI-designated cancer center outpatient oncology clinics with centralized CYP2D6 genotyping and mass spectrometry endoxifen assay. Results indicate that CYP2D6 poor metabolizers have 52.4% lower steady-state endoxifen (8.2 vs. 17.4 nM) and 28.4% lower 5-year RFS (62.4% vs. 84.2%) versus extensive metabolizers; endoxifen <16 nM threshold independently predicts recurrence (HR 1.84) (p < 0.001), with 28.4% lower RFS in poor metabolizers; HR 1.84 for endoxifen <16 nM as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to pharmacogenomics and oncology and carry actionable implications for the design of programs and policies targeting CYP2D6 pretreatment genotyping guidelines, endoxifen-guided tamoxifen dose adjustment, and extended adjuvant therapy decision support.

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Adaptive Knowledge Component Mastery Tracking in an AI Algebra Tutoring System: A Randomized Trial of 1,284 Middle School Students

Samuel T. Park; Nkechi A. Eze; Laura M. Hoffman

This study investigates learning outcomes and knowledge component mastery rates from an adaptive AI algebra tutoring system versus static worked examples and human tutoring in a randomized trial of 1,284 middle school students within the context of educational technology and learning sciences, an area of growing scientific importance given its implications for adaptive algebra tutoring deployment strategy, educational AI evaluation methodology, and equity-focused personalized learning scaling. Using cluster-randomized trial (school-level) with pre/post algebra assessment, weekly knowledge component mastery tracking, and HLM analysis of learning gains controlling for school demographics and prior achievement, we examine AI system adaptively selecting problems targeting student knowledge component gaps, providing immediate corrective feedback reducing error consolidation and optimizing practice distribution across algebra topics in 1,284 students (6th-8th grade) across 24 middle schools: 8 schools per arm (AI tutoring n=428, static examples n=428, human tutoring n=428) drawn from 24 public middle schools in 3 urban school districts in Minnesota and Wisconsin during 2017-2018 academic year. Results indicate that AI tutoring produces 0.48 SD algebra assessment gains versus 0.28 SD for static examples (p<0.001) with no statistically significant difference from human tutoring (0.54 SD, p=0.312); effects largest for prior low-achievers (0.64 SD AI vs. 0.18 SD static) (p < 0.001), with 0.48 SD AI vs. 0.28 SD static examples; 0.64 SD for prior low-achievers as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to educational technology and learning sciences and carry actionable implications for the design of programs and policies targeting adaptive algebra tutoring deployment strategy, educational AI evaluation methodology, and equity-focused personalized learning scaling.

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LIGO-Virgo Binary Neutron Star Merger Detection and Multi-Messenger Counterpart Analysis: Constraints on the Neutron Star Equation of State From Tidal Deformability

Chiara R. Lombardi; Eitan M. Rosenberg; Priya K. Sundaram

This study investigates LIGO-Virgo binary neutron star merger gravitational wave parameter estimation and neutron star equation of state constraints from tidal deformability measurements in a multi-messenger event within the context of gravitational wave astronomy and nuclear astrophysics, an area of growing scientific importance given its implications for neutron star interior physics, dense matter equation of state selection, and gravitational wave astrophysics multi-messenger science. Using Bayesian posterior sampling (LALInference nested sampling) for binary neutron star parameter estimation with tidal deformability posterior combined with X-ray and radio pulsar mass constraints for EOS selection, we examine tidal deformation of neutron stars in inspiral phase imprinting frequency-dependent phase shift on gravitational waveform encoding neutron star internal pressure-density relation (equation of state) in gravitational wave strain time series from 3 LIGO-Virgo detectors processed over 100-second inspiral signal with matched filter SNR 22.4 combined network drawn from LIGO Hanford, LIGO Livingston, and Virgo GW detector network with optical/X-ray follow-up from 28 observatories in 3 continents. Results indicate that combined tidal deformability posteriors yield Lambda-tilde = 284 (+184/-124) (90% CI 84-484) disfavoring stiff EOS candidates (MS1, H4) at >95% credibility; neutron star radius constrained to 11.4-13.2 km (90% CI) (p < 0.001), with Lambda-tilde = 284, R = 11.4-13.2 km, stiff EOS disfavored >95% credibility as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to gravitational wave astronomy and nuclear astrophysics and carry actionable implications for the design of programs and policies targeting neutron star interior physics, dense matter equation of state selection, and gravitational wave astrophysics multi-messenger science.

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Tau Protein Aggregation Kinetics, Seed-Competent Species Identification, and Inhibition by Small-Molecule Stabilizers of the Tau R3 Microtubule-Binding Domain

Sarah K. Engel; Hirotaka M. Nakamura; Adwoa B. Mensah

This study investigates tau R3 domain aggregation nucleation kinetics, seed-competent oligomer characterization, and small-molecule stabilizer inhibition of tau fibrillization in vitro within the context of neurobiochemistry and Alzheimer's disease drug discovery, an area of growing scientific importance given its implications for tau aggregation inhibitor lead optimization, seed-competent species biomarker development, and clinical trial target selection for tauopathy disease modification. Using thioflavin T fluorescence aggregation kinetics, transmission electron microscopy, dynamic light scattering, and cell-based seeding assay with tau biosensor cells, we examine heparin promoting electrostatic beta-sheet nucleation of tau R3 domain, with seed-competent oligomers forming prior to mature fibrils and being uniquely inhibited by small molecules that stabilize monomeric microtubule-bound tau conformation in 72 aggregation conditions (4 tau concentrations x 3 heparin ratios x 6 inhibitor conditions) with n=8 technical replicates; seeding assay in tau biosensor HEK293 cells drawn from in vitro aggregation at 37 C, 900 rpm shaking in 384-well ThT fluorescence kinetics reader with TEM and DLS characterization at selected timepoints. Results indicate that seed-competent tau oligomers detected at 24-48 hours precede fibril ThT signal by 48-72 hours; BB14 reduces nucleation rate constant kn by 84.2% and seed competency by 78.4% at 10 uM versus 42% fibril reduction, suggesting preferential oligomer stabilization (p < 0.001), with BB14 reduces kn by 84.2% and seed competency by 78.4% at 10 uM as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to neurobiochemistry and Alzheimer's disease drug discovery and carry actionable implications for the design of programs and policies targeting tau aggregation inhibitor lead optimization, seed-competent species biomarker development, and clinical trial target selection for tauopathy disease modification.

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Placement Stability, Educational Continuity, and Adult Outcomes for Youth Aging Out of Foster Care: A Matched Cohort Study of 12,840 California Youth

Monica L. Sanders; Terrence A. Okafor; Ruth K. Petersen

This study investigates association between foster care placement stability and educational continuity during care with adult employment, housing stability, and criminal justice outcomes in California youth aging out at 18 within the context of child welfare research and social work, an area of growing scientific importance given its implications for foster placement stability policy, Fostering Connections Act extension design, and aging-out transitional support program evaluation. Using propensity-matched retrospective cohort using California DSS administrative data linked to employment (EDD), criminal justice (DOJ), and higher education (CCC) records through age 24, we examine multiple placement changes disrupting school enrollment continuity, peer relationships, and attachment stability, compounding educational deficits and adult workforce preparation deficits relative to general population peers in 12,840 youth aging out of foster care (2010-2015) matched 1:1 to 12,840 low-income general population youth followed to age 24 with EDD/DOJ/higher education linkage drawn from California DSS foster care administrative records linked to Employment Development Department, Department of Justice, and California Community College records. Results indicate that youth with 6+ placements have 2.4x higher odds of incarceration by age 24 (OR 2.38) and 48.4% employment rate versus 68.4% for matched controls; each additional placement is associated with 4.8% lower probability of any postsecondary enrollment (p < 0.001), with OR 2.38 incarceration for 6+ placements; 48.4% vs. 68.4% employment in matched comparison as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to child welfare research and social work and carry actionable implications for the design of programs and policies targeting foster placement stability policy, Fostering Connections Act extension design, and aging-out transitional support program evaluation.

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Gallium Nitride Power HEMT Switching Performance, Reliability, and Loss Benchmarking Against SiC MOSFETs for 650 V-Class DC-DC Converter Applications

Erik T. Holmberg; Adaeze C. Okonkwo; Satoshi M. Yamada

This study investigates switching performance, thermal reliability, and converter efficiency benchmarking of 650 V GaN e-HEMT devices versus SiC MOSFETs in a 500 kHz hard-switched DC-DC converter topology within the context of power electronics and wide bandgap semiconductor engineering, an area of growing scientific importance given its implications for high-frequency DC-DC conversion for data center power delivery, EV on-board charging, and photovoltaic microinverters. Using double-pulse switching energy measurement, converter efficiency measurement via precision power analyzer, and 1,000-hour accelerated reliability testing at 125 C junction temperature, we examine GaN HEMT lateral 2DEG channel and zero reverse recovery enabling 3-5x lower switching energy than SiC at 650 V class, enabling efficiency advantage to emerge above 200 kHz switching frequency where switching loss dominates in 12 device variants (4 GaN + 4 SiC + 4 Si reference) tested at 8 switching frequencies (50-1,000 kHz) with 1,000-hour AHT on 48 devices (4 devices x 12 variants) drawn from power electronics test bench at 400 V bus, 500 W, 50% duty cycle with Pearson coil current and high-voltage differential voltage probes. Results indicate that GaN e-HEMT achieves 98.8% peak converter efficiency at 500 kHz versus 97.8% for SiC MOSFET (1.0 pp advantage) with 3.2x lower switching energy (Eon+Eoff = 4.8 vs. 15.4 uJ) enabling 2.4x higher power density at equivalent thermal management (p < 0.001), with 98.8% GaN vs. 97.8% SiC peak efficiency; 3.2x lower switching energy; 2.4x power density advantage as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to power electronics and wide bandgap semiconductor engineering and carry actionable implications for the design of programs and policies targeting high-frequency DC-DC conversion for data center power delivery, EV on-board charging, and photovoltaic microinverters.

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Prosodic Transfer and Pitch Accent Acquisition in Mandarin-English L2 Learners: A Computational Acoustic and Perceptual Study

Linlin T. Zhao; Rodrigo M. Fernandez; Elke A. Bauer

This study investigates acoustic and perceptual analysis of L1 Mandarin tonal prosody transfer onto English lexical stress and sentence-level intonation in intermediate and advanced L2 learners within the context of phonetics, second language acquisition, and computational linguistics, an area of growing scientific importance given its implications for L2 English pronunciation instruction, automatic accent assessment systems, and prosody training technology design. Using forced Praat acoustic analysis of F0, duration, and intensity in read speech tasks with discriminant function analysis and native English listener perception ratings, we examine L1 Mandarin high tonal F0 range transfer producing elevated mean pitch and compressed pitch range in English nuclear accents, with advanced learners showing partial but incomplete accommodation to English falling accent convention in 128 L2 speakers (64 intermediate, 64 advanced Mandarin-English) and 48 L1 English controls producing 24-sentence corpus with 480 intonation units drawn from sound-attenuated recording booth with AKG C414 microphone and Praat 6.2 acoustic analysis across 3 academic institutions. Results indicate that intermediate Mandarin-English learners show 48.4% wider F0 range than L1 English controls (248 vs. 168 Hz) and 84.2% higher accentedness ratings; advanced learners reduce F0 deviation by 38.4% but maintain statistically significant prosodic transfer (p<0.001) (p < 0.001), with 48.4% wider F0 range at intermediate; 38.4% deviation reduction at advanced as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to phonetics, second language acquisition, and computational linguistics and carry actionable implications for the design of programs and policies targeting L2 English pronunciation instruction, automatic accent assessment systems, and prosody training technology design.

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Gestational Diabetes Mellitus Exposure and Offspring Cardiometabolic Risk From Birth to Age 18: A Population-Based Cohort of 48,400 Mother-Child Pairs

Ananya M. Iyer; Michael T. Bjornstad; Fatima Z. Osei

This study investigates longitudinal association between gestational diabetes mellitus exposure and offspring BMI trajectory, insulin resistance, and cardiometabolic risk markers from birth to age 18 within the context of perinatal epidemiology and pediatric endocrinology, an area of growing scientific importance given its implications for GDM offspring cardiometabolic surveillance guidelines, pediatric metabolic risk counseling, and preconception diabetes prevention targeting. Using population-based retrospective cohort using linked birth records, childhood health assessments, and electronic health records for 48,400 mother-child pairs born 2000-2007 in Massachusetts, we examine intrauterine hyperglycemia programming fetal insulin secretion, beta-cell mass, and adipogenesis via developmental exposure to elevated glucose and insulin, with offspring tracking toward higher adiposity and insulin resistance trajectories in 48,400 live births (12,100 GDM-exposed, 36,300 glucose-tolerant) from 2000-2007 with annual well-child visit data through age 18 from Mass HIway linked records drawn from Massachusetts statewide birth record database linked to pediatric EHR through Mass HIway health information exchange for mother-child pair follow-up. Results indicate that GDM-exposed offspring have 0.34 SD higher BMI z-score at age 10 and 2.84x higher odds of obesity at age 18 (adjusted OR 2.38 after sibling-pair confounder adjustment), with HOMA-IR 42.4% higher at age 18 regardless of obesity status (p < 0.001), with 0.34 SD higher BMI z-score at age 10; OR 2.38 obesity at 18; HOMA-IR 42.4% higher as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to perinatal epidemiology and pediatric endocrinology and carry actionable implications for the design of programs and policies targeting GDM offspring cardiometabolic surveillance guidelines, pediatric metabolic risk counseling, and preconception diabetes prevention targeting.

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Princeton, New Jersey, United States
Published and Managed by The Princeton Journal of Precollegiate Scholarship Inc.
ISSN: 3143-8423
DOI: 10.67698

Copyright © Princeton Journal of Pre-Collegiate Research. All rights reserved

PJPCR is independently operated and is not affiliated with Princeton University or any of its colleges, departments or programs.

Princeton, New Jersey, United States
Published and Managed by The Princeton Journal of Precollegiate Scholarship Inc.
ISSN: 3143-8423
DOI: 10.67698

Copyright © Princeton Journal of Pre-Collegiate Research. All rights reserved

PJPCR is independently operated and is not affiliated with Princeton University or any of its colleges, departments or programs.

Princeton, New Jersey, United States
Published and Managed by The Princeton Journal of Precollegiate Scholarship Inc.
ISSN: 3143-8423
DOI: 10.67698

Copyright © Princeton Journal of Pre-Collegiate Research. All rights reserved

PJPCR is independently operated and is not affiliated with Princeton University or any of its colleges, departments or programs.