Digital Commons Network^™

Associations Between Accelerometer-Measured Physical Activity And Sleep Duration And Health Indicators In Children And Adolescents With Attention-Deficit Hyperactivity Disorder: A Systematic Review And Meta-Analysis, Xiao Liang, Hui Qiu, Justin A. Haegele, Xiao Li, Minghui Li, Jiayue Li, Shirley Xin Li

Human Movement Studies & Special Education Faculty Publications

Objective

This systematic review and meta-analysis synthesized available studies to explore relationships between accelerometer-measured physical activity (PA) levels or sleep duration and health-related outcomes in children and adolescents with attention-deficit hyperactivity disorder (ADHD).

Methods

Following the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines, the six databases APA PsychInfo, CINAHL Ultimate, Embase, MEDLINE, SPORTDiscus with Full Text and Web of Science were searched from inception through July 2024. The correlation coefficient (r) was employed to determine the effect size in the meta-analysis. A random-effects model was utilised to estimate the potentially heterogeneously distributed effect sizes with a 95 % …

Professional Standards For School-Based Behavior Analysts (2nd Edition), Selena J. Layden, Emily Muise, Karen L. Berlin, Samantha Gregory, Daniel Irwin, Kaylan Long, Daria K. Lorio-Barsten, Jennifer L. O’Berry, Hannah Riddle

Human Movement Studies & Special Education Faculty Publications

Public educational settings are unique and complex environments that require specific knowledge and skills for the professionals that work in these environments. School-based behavior analysts can be a great asset to public schools. However, these professionals must be able to firmly understand and perform the responsibilities of a behavior analyst in collaboration with educators and service providers in a public school setting. The presence of behavior analysts in public schools is still relatively new, when compared with other specialized services. Therefore, behavior analysts, teachers, administrators, and others should focus on collaboration to promote the success for all stakeholders with an …

Accelerometer-Measured Physical Activity Among Children And Adolescents With And Without Neurodevelopmental Disorders: A Systematic Review And Meta-Analysis, Xiao Liang, Raffy C.F. Chan, Justin A. Haegele, Sean Healy, Richard H. Xu, Chang Liu, Ming Chen, Minghui Li, Hui Zhang, Cindy H.P. Sit, David H.K. Shum

Human Movement Studies & Special Education Faculty Publications

Purpose

Physical inactivity is a health concern for children and adolescents with neurodevelopmental disorders (NDDs) as it directly increases their risk of developing various health problems. Evidence on differences in accelerometer-assessed physical activity between children and adolescents with and without NDDs is inconclusive. And age- and body mass index (BMI)-related effects on physical activity remain unclear.

Methods

The systematic literature searches were performed in 6 databases up to March 2025. Methodological quality was evaluated by the Newcastle-Ottawa Scales. Data were pooled using a random-effects model. Hedges' g was used to express the effect size index with 95 % confidence interval …

Considerations For School Leadership In Leveraging School-Based Behavior Analysis For Systemic Improvement In Public Education, Virginia Public Schools Behavior Analyst Network, Kira Austin, Elizabeth Boynton, Amanda K. Cash, Meredith Eads, Daniel Irwin, Selena Layden, Daria K. Lorio-Barsten, Emily Muise, Nadine Pittman, Felicia Shelton, Indya Watts-Graves

Human Movement Studies & Special Education Faculty Publications

Public schools face significant challenges, including rising student behavioral needs, chronic absenteeism, and high rates of teacher burnout. These issues are interconnected with and inextricably linked to a need for effective, evidence-based behavioral supports. Educators frequently enter the field lacking the necessary skills and training to manage complex student behavior, often resulting in a reliance on punitive practices that exacerbate problems.

This paper proposes that the expertise of school-based behavior analysts (SBBAs), who are Board Certified Behavior Analysts® (BCBAs®) specializing in education, offers a powerful, underutilized solution. SBBAs are trained in applied behavior analysis (ABA), a data-driven science focused on …

Felt Ambivalence Weakens The Attitude-Intention Pathway For Regular Leisure-Time Physical Activity In Chinese Adolescents: A Three-Wavee Prospective Study, Yaogang Han, Yubing Wang, Pan Li, Guohua Zheng

Human Movement Studies & Special Education Faculty Publications

Background: Favorable attitudes toward regular leisure-time physical activity may not always translate into intention if adolescents feel ambivalent about the behavior. This study tested whether felt ambivalence weakens the prospective attitude–intention association and the indirect effect of attitude on later behavior through intention. Methods: Chinese adolescents (N = 1714; Grades 7–12; mean age = 15.0 years) completed a three-wave survey at approximately two-week intervals. Wave 1 assessed attitudes toward regular leisure-time moderate-to-vigorous physical activity, felt ambivalence, and physical activity habit; Wave 2 assessed intention; and Wave 3 assessed leisure-time physical activity. Moderated mediation was tested in a structural equation model …

From Intention To Enactment: Action Planning And Habit Automaticity Distinguish Successful From Unsuccessful Intenders To Engage In Regular Leisure-Time Moderate-To-Vigorous Physical Activity, Yaogang Han, Yubing Wang, Pan Li, Binn Zhang

Human Movement Studies & Special Education Faculty Publications

University students often intend to exercise regularly but fail to translate intention into action. The present study tested which post-intentional processes distinguish successful from unsuccessful intenders in self-reported regular leisure-time moderate-to-vigorous physical activity (MVPA) enactment. Chinese undergraduates from 10 universities completed a three-wave survey administered at roughly two-week intervals. Habit automaticity was assessed at Wave 1, intention together with action planning and coping planning at Wave 2, and self-reported regular-exercise status at Wave 3. Because the dependent variable was assessed using a single stage-based self-report item, the findings should be interpreted as explaining self-reported regular-exercise status rather than objectively measured …

The Relationship Between Physical Activity, Sleep, And Hallucinations In Adults With Charles Bonnet Syndrome, Jarrod Hollis, Rohit Narayan, Eldre W. Beukes, Rosie Lindsay, Aliyah Bharwani, Umair Mughal, Ikra Yaqoob, Justin A. Haegele, Scott Muriden, Peter M. Allen

Human Movement Studies & Special Education Faculty Publications

Physical activity levels, hallucination experiences, sleep quality, and perceived stress were assessed using a survey administered to 57 adults with a confirmed diagnosis of Charles Bonnet Syndrome (CBS). Physical activity demonstrated a significant negative correlation with hallucination severity (r = –0.335, p = 0.011, two-tailed). A significant negative correlation was also observed between physical activity and perceived stress (r = –0.497, p < 0.001, two-tailed). In contrast, no significant association was identified between hallucination frequency and sleep disruption or insomnia. These findings suggest that engaging in appropriate levels of physical activity may help reduce the severity of hallucinations and mitigate stress among individuals with CBS. The observation that higher levels of physical activity are associated with reduced hallucination burden may help the development of evidence-based management strategies for CBS. Additionally, the finding that physical activity was significantly related to hallucination severity, whereas sleep disruption was not, merits deeper exploration in future research.

Tramadol For Treatment Of Neurogenic Cough: A Retrospective Case Series, Benjamin Joseph Rubinstein, Sheela Saidha, John Todd Sinacori

Department of Otolaryngology (ENT) Faculty Publications

Objectives

Explore the efficacy of tramadol for neurogenic cough and describe the longitudinal treatment experience.

Methods

A retrospective case series of adults with chronic cough who were treated with tramadol for neurogenic cough. A complete response was defined as no pathologic coughing, and a partial response was defined as 50% or greater reduction in severity or frequency.

Results

Sixty-nine patients were included. 38% of patients reported a complete response with an additional 33% reporting a partial response. The most common successful dosing regimen was 50 mg BID. Age, gender, and BMI did not impact treatment response. Patients with a history …

Single Intratympanic Injection Of Proprietary Brain-Derived Neurotrophic Factor (Oto-413) In Subjects With Speech-In-Noise Hearing Impairment: A Randomized, Dose Escalating, Double-Blind, Placebo-Controlled Phase 1/2 Study, Alan C. Foster, Jeffery J. Anderson, David R. Moore, Morgan Oktela Fuentes, Yiwei Wang, Peter G. Volsky, K. Paul Boyev, Victoria A. Sanchez

Department of Otolaryngology (ENT) Faculty Publications

Purpose

To evaluate the safety and tolerability and exploratory efficacy of OTO-413, an intratympanic-administered, sustained release formulation of brain-derived neurotrophic factor (BDNF) in a thermoreversible gel, in participants with speech-in-noise hearing difficulties.

Methods

This was a single dose, dose-ascending, randomized, double-blind, Placebo-controlled Phase 1/2 study conducted at 7 enrolling clinical sites in the U.S. 110 participants (56% female) enrolled had self-reported speech-in-noise (SIN) difficulties that were confirmed by a SIN test and were randomized to OTO-413 or Placebo. OTO-413 dose range was escalated from 0.01 mg to 1.5 mg within 7 Cohorts. Safety evaluations included monitoring for treatment-emergent adverse events, …

An Association Test For Ordinal Outcomes In Clustered Data With Informative Cluster Size, Hasika K. Wickrama Senevirathne, Sandipan Dutta

Mathematics & Statistics Faculty Publications

In cluster-correlated data, the number of observations in a cluster can be associated with the outcome from that cluster. This phenomenon is known as informative cluster size which can occur in cluster-randomized clinical trial data. Several studies have found that ignoring the issue of informative cluster size can produce biased results in the analysis of clustered data. Most of the existing methods for addressing informative cluster size are suited to continuous outcomes. However, ordinal outcomes and covariates are often encountered in clustered data obtained from large clinical studies. The existing methods for ordinal association testing in clustered data can produce …

Logistic-T Multinomial Mixture Model For Clustering For Microbiome Data, Wenshu Dai, Yuan Fang, Sanjeena Subedi

Mathematics & Statistics Faculty Publications

The logistic-normal multinomial distribution has been used for modelling microbiome data obtained from high-throughput sequencing technologies, which are compositional in nature. A logistic-normal multinomial distribution is a hierarchical multinomial distribution that assumes the latent variable which are the additive log-ratio (ALR) transformed proportions in a multinomial distribution follows a Gaussian distribution. Model-based clustering algorithms have also been developed for clustering microbiome data based on the logistic-normal models. However, the Gaussian assumption may violated when the ALR transformed variable exhibit heavy-tailed distributions or has outliers. Our study introduces a novel mixture of logistic-t multinomial models that effectively address these challenges. Utilizing …

Determining The Electric Field In A 10 Ns Pulsed Plasma In Fuel-Air Mixtures Using Efish, Md Ziaur Rahman, Christopher J. Kliewer, Brian D. Patterson, Chunqi Jiang

Bioelectrics Publications

Transient plasma ignition (TPI) utilizes non-equilibrium plasmas, produced by nanosecond high-voltage pulses, to improve lean-fuel combustion performance and reduce emission. It is known that the relatively high reduced electric field (E/N) in TPI plays an important role in generating energetic electrons and facilitating energy-efficient radical productions, resulting in reliable ignition for lean combustion. Determining the reduced electric field in the discharge is hence important for the understanding of the TPI process and ultimately allowing for the control of the plasma chemistry. This study reports spatiotemporally resolved measurements of the electric field (E) in a 10 ns pulsed plasma that is …

Ammonia Synthesis By Nanosecond Pulsed Atmospheric Pressure Plasma Jets Impinging On Water, Zach Caudell, Lynnet Rich, Olga Pakhomova, Chunqi Jiang

Bioelectrics Publications

Developing energy-efficient technologies for carbon-neutral ammonia (NH₃) synthesis is critical for decentralized fertilizer production and global decarbonization. This study investigates generating NH₃ from water using a nanosecond pulsed atmospheric pressure plasma jet (ns‑APPJ) operating in either N₂ or dry air. The plasma jet reactor employed approximately 250 ns, up-to-22 kV pulses at 500 Hz to sustain a nonequilibrium discharge impinging directly on static liquid water. The kinetics, energy efficiency, and product selectivity of NH3 formation were quantified as functions of the pulse voltage, repetition frequency (PRF), and gas flow rate. NH₃ production increased linearly with treatment time and scaled strongly …

Reward Deficits In Co-Occurring Social Anxiety And Depression: The Roles Of Anhedonia, Boredom, Loneliness, And Covid-19 Social Restriction, Nathan M. Hager, Alicia L. Milam, Hannah C. Hamrick, Benjamin Swanson, Matt R. Judah

Psychology Faculty Publications

Prior research points toward reward deficits as crucial to the link between social anxiety disorder and major depressive disorder. However, studies have not explored specific types of reward deficits or how social-environmental factors may impact them. The current study examined whether the indirect effects of three reward deficits (anhedonia, boredom, and loneliness) accounted for the connection between social anxiety and depression. Questionnaires were collected in a sample of college students (N = 523) during the first year of the COVID-19 pandemic, allowing examination of environmental stressors (i.e., remote learning and current friend network size) on reward deficits. Indirect effect models …

Chesapeake Bay Water Clarity: Challenges And Successes, Jessica S. Turner, Carl T. Friedrichs, David B. Parrish, Kelsey A. Fall

OES Faculty Publications

The Chesapeake Bay is a large estuarine system spanning multiple jurisdictions and serves as a model for estuarine health worldwide. Historically, nutrient loading degraded water quality, prompting the need for regulation. Water clarity, one component of water quality, is vital for benthic communities and serves as a key indicator of overall ecosystem health. Here, physical resuspension and salinity gradients, nutrient and sediment inputs, production of organic detritus by phytoplankton, and benthic communities all interact to drive clarity patterns, with high spatial variability. Trends over the last 50 years show improvement, though with a temporary increase in organic detritus in response …

Diatom Community Response To High And Low Iron Upwelling Plumes In The California Current System, Sveinn V. Einarsson, Kimberly Powell, Claire Till, Tyler Coale, P. Dreux Chappell

OES Faculty Publications

Diatoms are important primary producers, accounting for most of the oceanic production and carbon export relative to other photosynthetic eukaryotes. There are important differences among diatom species that enable them to proliferate in different environments. Some have nutrient storage capabilities or lower nutrient quotas suited for oligotrophic oceans. Bloom-forming diatoms are typically found in nutrient-rich coastal waters where they respond quickly to nutrient pulses and can influence biogeochemical cycling in the ocean after blooms. As many physiological differences affect biomass and export, it is important to better understand how physical and chemical parameters influence diatom community composition, especially in dynamic …

Modeling Upper Ocean Ecosystem Dynamics In Response To Interannual Sea-Ice Variability In The Western Antarctic Peninsula, Catherine R. Czajka, Jessica S. Turner, Sharon Stammerjohn, Heather H. Kim, Oscar Schofield, Benjamin T. Saenz, Scott C. Doney

OES Faculty Publications

In the Western Antarctic Peninsula (WAP), marine plankton dynamics are tightly linked to the interannual variability in environmental conditions, including phenological shifts in sea-ice seasonality. To explore these linkages, we use a 1-dimensional vertical ocean-ice-ecosystem model (KPP-Eco-Ice, or KEI) that simulates physical and ecosystem conditions at a continental shelf mooring location in the Palmer Long Term Ecological Research program sampling grid. KEI allows for year-round examination of the ecosystem in a region where in situ observations on the shelf are limited to January. Comparisons are made between seasonal sea-ice retreat, mixed layer depth, primary productivity, and phytoplankton relative abundance, grazing, …

Recirculated Submarine Groundwater Discharge Dominates Nutrient Inputs And Enhances Eutrophication Risk In A Coastal Lagoon, Júlia Rodriguez-Puig, Clara Ruiz-González, Marc Diego-Feliu, Irene Alorda-Montiel, Aaron Alorda-Kleinglass, Daniel Romano-Gude, Andrea G. Bravo, Júlia Dordal-Soriano, Javier Gilabert, Sophia Bergeler, Celine Lavergne, Gemma Casas, Marisol Manzano, Jordi Garcia-Orellana, Valentí Rodellas

OES Faculty Publications

Submarine groundwater discharge (SGD) is a widely recognized pathway for nutrient transport to coastal systems. Prior studies overlook the unique biogeochemical signatures of different SGD pathways, neglecting their differences in biogeochemical transformations and spatiotemporal factors. Here, we present an integrated assessment of nutrient delivery through three SGD pathways (fresh SGD, long‐scale recirculated SGD, and short‐scale porewater exchange), alongside surface water inputs, to evaluate their seasonality and impact on nutrient dynamics in a coastal lagoon. We conducted five field surveys in March, July, and November 2021, July 2024, and March 2025 in the Mar Menor lagoon, an ecosystem facing severe ecological …

Efficient Preservation Of Old Methane-Derived Organic Carbon In Deep-Sea Surface Sediments, Rui Bao, Yangli Che, Mingzhi Liu, Naiyu Zhang, Yang Zhou, Lihua Dong, Shen Li, Owen A. Sherwood, Min Yu, Zongheng Chen, Shengxiong Yang, Nan Wang, Longhai Zhu, Jiawang Chen, Mutai Bao, Haoshuai Li, Luonan Chen, Weifeng Wu, Haiyue Ma, David J. Burdige

OES Faculty Publications

Methane released from the subseafloor is significantly attenuated during upward migration, yet the preservation of methane-derived organic carbon (OC) in global deep-sea sediments remains poorly understood. Here, we measured carbon isotopes coupled with temperature-ramped analyses on various methane seepage sediments. Our results reveal a correlation between the radiocarbon (¹⁴)C) content in deep-sea surface sediments and sulfate-methane transition depth. Notably, our findings suggest that a substantial amount of (¹⁴)C-depleted OC may originate from deep-seated methane and is efficiently preserved in surface seepage sediments. We propose that the efficient OC preservation is related to microbial-mediated aggregate formation at the seawater-sediment interface, where …

Regional Oceanographic Controls On Water Column Nitrogen Fixation In Northern Australian Waters, Douglas G. Capone, Ajit Subramaniam, Yubin Raut, Joseph P. Montoya, Margaret R. Mulholland, Rachel Ann Foster, Miles Furnas, Edward J. Carpenter

OES Faculty Publications

Large blooms of the diazotrophic cyanobacteria, Trichodesmium, have been re-ported along the north coast of Australia and are readily evident in remote sensing images. During a research cruise in November 1999, we sampled from Townsville to Broome, examined Trichodesmium population densities and their rates of carbon and N₂ fixation alongside microscopy-based cell counts of them and other cyanobacte-rial diazotrophs. Additionally, we also enumerated the picophytoplankton community using flow-cytometry, measured bulk chlorophyll concentrations, carbon and N₂ fixation rates, and water column hydrography, enabling comparison of diazotrophic and picophytoplankton functional groups across the system. Agglomerative hierarchical clustering analysis of physicochemical oceanographic …

Unintended Consequences Of Estuarine Management Within The Trajectory Of Recovery: Examples From The Chesapeake Bay, Jessica S. Turner, Fei Da, Molly M. Mitchell

OES Faculty Publications

Estuaries are vital ecosystems that support biodiversity, human populations, and economic activities such as fisheries, aquaculture, and tourism. Managing estuarine systems often involves interventions to regulate sediment and nutrient inputs with the goal of improving water quality, and subsequently the economic values of the estuary. However, these management strategies can produce unintended consequences. The Chesapeake Bay is an estuary recovering from eutrophication which provides clear case studies for these patterns. In the Chesapeake Bay, decreased sediment inputs, resulting from shoreline stabilization and watershed modifications, can impair marsh resilience to sea level rise and disrupt sediment-light-algal interactions affecting water clarity. Likewise, …

Microplastics Suppress Copepod Grazing Of The Harmful Algal Bloom-Forming Dinoflagellate, Alexandrium Catenella, Megan Ladds, Christopher Gobler

OES Faculty Publications

While harmful algal blooms (HABs) are prominent occurrences in coastal zones where microplastic concentrations are maximal, the manner in which microplastics may influence food webs and HABs is poorly understood. This study explored how polystyrene microplastics affected copepod grazing of the saxitoxin-synthesizing harmful dinoflagellate, Alexandrium catenella, as well as a non-toxic dinoflagellate, Gymnodinium aureolum. Experiments were performed using multiple densities of microplastics (250 – 10,000 mL^–¹) of differing sizes (4 and 10 µm), as well as multiple densities of microalgae in microplates. The addition of 10 µm microplastics at densities of 1000 – 10,000 beads mL^{– …}

Differences In Sideerophore Production During The Growth Of Phytoplankton In Southern Ocean Incubation Experiments Under High- And Low-Iron Conditions, Randelle M. Bundy, Kristen N. Buck, Bethany D. Jenkins, P. Dreux Chappell, Daniel J. Repeta, Alexa Sterling, Shannon M. Yang, Laura Holland, Léo Mahieu, Laura E. Moore

OES Faculty Publications

Iron is an important micronutrient required by marine microorganisms. The Southern Ocean is an ecosystem where primary production is limited by the availability of iron, but how microorganisms in this region adapt to low-iron conditions or respond to episodic iron inputs is understudied. We tested how external iron additions would impact bacterial production of siderophores during phytoplankton growth using shipboard incubation experiments under a range of iron conditions. Similar heterotrophic bacteria communities and phytoplankton biomass were observed whether iron was added from the continental margin or as inorganic iron. Under both high- and low-iron conditions, the heterotrophic bacteria community remained …

Gradient-Based, Post-Optimality Sensitivity Analysis With Respect To Parameters Of State Equations, Gene Hou, Jonathan Degroff

Mechanical & Aerospace Engineering Faculty Publications

Design optimization is a computational tool that can enable a designer to investigate the effectiveness of a design concept in an organized format. However, this design process requires the design variables, constraints, and objective function to be properly defined and expressed in mathematical forms. Post-optimality analysis thus becomes a necessary step to investigate different variations in the problem formulation and parameters to ensure that optimization produces a stable and trustworthy outcome. One efficient way to achieve this aim is to compute the local derivative of the optimized objective function with respect to the optimization problem parameters, such as bounds on …

Uncertainty-Aware Estimation, Planning, And Control For Tracking Multiple Drifting Patches In Flow Fields, Daniel O. Akanji, Krishnanand N. Kaipa, Cong Wei

Mechanical & Aerospace Engineering Faculty Publications

In this study, we present a replay-based framework for uncertainty-aware persistent tracking of multiple advected surface patches using an autonomous marine vehicle operating in spatiotemporal-varying currents. The method combines three components: local flow estimation, covariance-aware patch-boundary propagation with intermittent boundary fusion, and mission-level scheduling over multiple patches. Each patch is represented by a polygonal boundary, whose vertices are propagated through the estimated flow field while carrying per-vertex covariance, thereby quantifying uncertainty growth during advection. A flow-aware gain-scheduled linear quadratic regulator (LQR) was designed to shape the desired surge speed to take advantage of favorable currents. When the vehicle services a …

Influence Of Motion Artifacts On Instantaneous Frequency Based Heart Rate Variability Of Arterial Pulse Signals Measured By A Tactile Sensor: An Analytical Study, Mamun Hasan, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

Objective: Heart rate variability (HRV), quantified via the instantaneous frequency (IF) of arterial pulse signals, is a key indicator of cardiovascular (CV) regulation. This study presents a theoretical and experimental investigation of how motion artifacts (MA) influence IF-and thus HRVmeasured with a tactile sensor, emphasizing underlying mechanisms rather than population-level validation. Approach: Building on a previously developed single-degree-of-freedom (SDOF) model of the tissue-contact-sensor (TCS) stack between the sensor and the artery, MA is represented as low-frequency baseline drift and time-varying system parameters (TVSP) of the TCS stack. Analytical expressions quantify the effect of MA on the IF of each harmonic …

Mechanical-Medical Convergence In Heart Failure: Artificial Intelligence, Finite-Element Modeling, And 3d Printing For Diagnosis And Prognosis, Quazi Noor E. Sabrina, Quazi Md Zobaer Shah, Quazi Noor E. Sohela, Md Mahabub Hasan Mousum, Md. Moyeen Uddin Chisty, Quazi Md. Akbar Shah

Mechanical & Aerospace Engineering Faculty Publications

Heart failure remains a leading cause of global morbidity and mortality, yet routine clinical indices often miss the regional biomechanical disturbances that drive progression and shape treatment response. This State-of-the-Art review examines how finite-element (FE) modeling, additive manufacturing, and artificial intelligence (AI) are converging to improve the diagnosis, phenotyping, procedural planning, and prognostic assessment of heart failure (HF). Although these technologies have matured in structural heart disease and transcatheter intervention research, their greatest translational potential may lie in HF, where patient-specific ventricular remodeling, myocardial stress–strain heterogeneity, valve-ventricular coupling, and device-tissue interaction are incompletely captured by conventional clinical indices. We synthesize …

Radical-Based Oxidative Pretreatment Enhances Biofuel Production From Lignocellulosic Biomass Via Hydrothermal Liquefaction, João Vitor Dos Santos, Louis C. Bondurant, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The sustainable production of biofuels from lignocellulosic biomass is a central goal in the transition to low-carbon energy systems. However, hydrothermal liquefaction (HTL), a promising thermochemical conversion pathway, is constrained by the high oxygen content and complex aromatic structure of lignin, which lowers bio-oil quality. Here, we used a model system of brown-rot-degraded white oak (Quercus alba) to test whether radical-based oxidative pretreatment could enhance HTL performance by converting lignin into more aliphatic intermediates. Oxidation was performed under simulated Fenton conditions using fixed Fe(II) (60 ppm) and two hydrogen peroxide concentrations (3 and 8 M), resulting in extensive lignin depolymerization …

Twenty-One Years Of Global Atmospheric Chlorine Inventories From Atmospheric Chemistry Experiment Fourier Transform Spectrometer (Ace-Fts) Measurements, N. Raymond, P. Bernath, C. Boone, M. P. Chipperfield

Chemistry & Biochemistry Faculty Publications

We present atmospheric chlorine inventories over 21 years (2004-2024) and five latitude bands (82-60°N, 60-30°N, 30°N-30°S, 30-60°S, 60-82°S) across altitudes from the surface up to 61 km. These inventories were calculated using the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) version 5.3 retrievals of the volume mixing ratios (VMRs) of 13 chlorine-containing species. Of these, five are product gases: HCl, HOCl, ClONO₂, COClF, COCl₂, and eight are source gases: CCl₄, CH₃Cl, CFC-11 (CCl₃F), CFC-12 ( CCl₂F₂), CFC-113 (CClF₂CCl₂F}), HCFC-22 (CHF₂Cl), HCFC-141b ( C₂H₃Cl₂F), and HCFC-142b (C₂H₃}Cl₂F). Where necessary, ACE-FTS data were supplemented with data from the TOMCAT 3-D chemical transport model, …

Scanning Electron Microscopy As A Potential Tool For Distinguishing Charcoal From Dark, Oxidized, Biomass, João Vitor Dos Santos, Aleksandar I. Goranov, Lais Gomes Fregolente, Joao Marcos De Lima-Faria, Diego Stefani Teodoro Martinez, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Condensed aromatic carbon (ConAC) is widely used as a proxy for organic materials derived from biomass burning. However, recent evidence shows that ConAC can be also formed through nonpyrogenic oxidative processes. This study presents a proof-of-concept investigation using scanning electron microscopy (SEM) to distinguish charcoal from dark, ConAC-rich materials produced by ambient oxidation of biomass. Pine wood exposed to long-term iron-mediated oxidation was compared with unaltered wood and a controlled laboratory-generated charcoal reference. Conventional geochemical analytical methods, including benzenepoly(carboxylic acid) (BPCA) analysis, Fourier transform–ion cyclotron resonance–mass spectrometry (FT-ICR-MS), solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis, confirmed substantial …