Engineering Commons^™

Quaternary Ammonia Compounds In Disinfectant Products: Evaluating The Potential For Promoting Antibiotic Resistance And Disrupting Wastewater Treatment Plant Performance, Zihao Lu, Anna K. Mahony, William A. Arnold, Christopher Marshall, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Quaternary ammonium compounds (QACs) are a class of compounds that were widely used as disinfectants during the COVID-19 pandemic and continue to be used as disinfecting agents. After consumer usage, QAC concentrations are diluted in wastewater as they enter wastewater treatment plants. At sub-inhibitory concentrations, QACs may have unintended repercussions, including increased antibiotic resistance and inhibition of process performance in wastewater treatment plants. This review first summarizes how QACs inhibit bacteria and then highlights the mechanisms by which QACs can promote antibiotic resistance in general. Reported environmental concentrations of QACs are compared to concentrations that are suspected to impact antibiotic …

The Effects Of Lead, Copper, And Iron Corrosion Products On Antibiotic Resistant Bacteria And Antibiotic Resistance Genes, Veronika Folvarska, San Marie Thomson, Zihao Lu, Maya Adelgren, Adam Schmidt, Ryan J. Newton, Yin Wang, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Antibiotic resistance is a public health crisis. Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are present in drinking water distribution systems. Metals are known selective pressures for antibiotic resistance, and metallic corrosion products are found within drinking water distribution systems due to the corrosion of metal pipes. While corrosion products are a source of metals, the impact of specific corrosion products on antibiotic resistance has not been investigated. The objective of this study was to determine the impact of six corrosion products—CuO, Cu₂O, Pb₅(PO₄)₃OH, β-PbO₂, Fe₃O …

Peroxi-Electrocoagulation For Treatment Of Trace Organic Compounds And Natural Organic Matter At Neutral Ph, Donald R. Ryan, Patrick J. Mcnamara, Claire K. Baldus, Yin Wang, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Iron-based oxidation technologies can be advantageous for mitigating trace organic compounds (TOrCs) during water and wastewater treatment due to their production of hydroxyl radicals. However, iron-based oxidation often occurs at acidic pH to promote Fenton's reaction, which limits the processes' feasibility for treatment applications. This study focused on utilizing iron-electrocoagulation (EC) paired with ex situ H₂O₂ addition (peroxi-electrocoagulation [EC:H₂O₂]) to promote oxidative reactions at neutral pH conditions. The hydroxyl radical probe para-chlorobenzoic acid (pCBA) was used to gauge oxidant activity and serve as a representative TOrC. The impact of water …

Antibiotic Resistance In Urban Stormwater: A Review Of The Dissemination Of Resistance Elements, Their Impact, And Management Opportunities, Kassidy N. O'Malley, Walter M. Mcdonald, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

The public health crisis of antibiotic resistance is a growing threat across the world that is only expected to intensify in the coming years. The cycling of antibiotic resistance genes (ARGs) in the environment via urban stormwater runoff is one means by which humans are exposed to resistant bacteria as traditional gray stormwater infrastructure facilitates the transport of resistance elements into water bodies utilized by the public. In this review, existing research on the occurrence of ARGs in urban stormwater runoff is critically reviewed with the goal of determining the role of stormwater in the dissemination and development of antibiotic …

Impact Of Corrosion Inhibitors On Antibiotic Resistance, Metal Resistance, And Microbial Communities In Drinking Water, Lee K. Kimbell, Emily Lou Lamartina, Stan Kohls, Yin Wang, Ryan J. Newton, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Corrosion inhibitors, including zinc orthophosphate, sodium orthophosphate, and sodium silicate, are commonly used to prevent the corrosion of drinking water infrastructure. Metals such as zinc are known stressors for antibiotic resistance selection, and phosphates can increase microbial growth in drinking water distribution systems (DWDS). Yet, the influence of corrosion inhibitor type on antimicrobial resistance in DWDS is unknown. Here, we show that sodium silicates can decrease antibiotic resistant bacteria (ARB) and antibiotic-resistance genes (ARGs), while zinc orthophosphate increases ARB and ARGs in source water microbial communities. Based on controlled bench-scale studies, zinc orthophosphate addition significantly increased the abundance of ARB …

An Inexpensive, Reproducible Method To Quantify Activated Sludge Foaming Potential: Validation Through Lab-Scale Studies And Year-Long Full-Scale Sampling Campaign, Grace K. Scarim, Emily Lou Lamartina, Kaushik Venkiteshwaran, Daniel Zitomer, Ryan J. Newton, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Activated sludge is a conventional treatment process for biochemical oxygen demand (BOD) and total suspended solids (TSS) removal at water resource recovery facilities (WRRFs). Foaming events are a common operational issue in activated sludge and can lead to decreased treatment efficiency, maintenance issues, and potential environmental health risks. Stable foaming events are caused by biological and chemical drivers (i.e., microbes and surfactants) during the aeration process. However, foaming events are difficult to predict and quantify. We present an inexpensive and easy-to-use method that can be applied at WRRFs to quantify foaming potential. Subsequently, the method was applied over a year-long …

Development Of Fibroblast/Endothelial Cell-Seeded Collagen Scaffolds For In Vitro Prevascularization, Daniela S. Masson-Meyers, Fahimeh Tabatabaei, Lane Steinhaus, Jeffrey M. Toth, Lobat Tayebi

Biomedical Engineering Faculty Research and Publications

The development of vascularized scaffolds remains one of the major challenges in tissue engineering, and co-culturing with endothelial cells is known as one of the possible approaches for this purpose. In this approach, optimization of cell culture conditions, scaffolds, and fabrication techniques is needed to develop tissue equivalents that will enable in vitro formation of a capillary network. Prevascularized equivalents will be more physiologically comparable to the native tissues and potentially prevent insufficient vascularization after implantation. This study aimed to culture human umbilical vein endothelial cells (HUVECs), alone or in co-culture with fibroblasts, on collagen scaffolds prepared by simple fabrication …

Extended Training Improves The Accuracy And Efficiency Of Goal-Directed Reaching Guided By Supplemental Kinesthetic Vibrotactile Feedback, Valay A. Shah, Ashiya Thomas, Leigh A. Mrotek, Maura Casadio, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Prior studies have shown that the accuracy and efficiency of reaching can be improved using novel sensory interfaces to apply task-specific vibrotactile feedback (VTF) during movement. However, those studies have typically evaluated performance after less than 1 h of training using VTF. Here, we tested the effects of extended training using a specific form of vibrotactile cues—supplemental kinesthetic VTF—on the accuracy and temporal efficiency of goal-directed reaching. Healthy young adults performed planar reaching with VTF encoding of the moving hand's instantaneous position, applied to the non-moving arm. We compared target capture errors and movement times before, during, and after approximately …

Relationships Among Shoulder Rotational Strength, Range Of Motion, Pitching Kinetics, And Pitch Velocity In Collegiate Baseball Pitchers, Janelle A. Cross, Austin William Higgins, Cody C. Dziuk, Gerald F. Harris, William G. Raasch

Biomedical Engineering Faculty Research and Publications

Relationships among shoulder rotational strength, range of motion, pitching kinetics, and pitch velocity in collegiate baseball pitchers. J Strength Cond Res 37(1): 129–135, 2023—Throwing shoulder injuries are the most common type of injury experienced by baseball pitchers. Weakness in the shoulder musculature and insufficient throwing arm range of motion are both risk factors for developing a shoulder injury. The goal of this study was to determine correlations among shoulder rotational strength, range of motion, pitching kinetics, and pitch velocity in collegiate pitchers. Thirteen uninjured male college pitchers were evaluated. Clinical measures included shoulder internal and external rotation range of motion, …

Data-Integrity Aware Stochastic Model For Cascading Failures In Power Grids, Rezoan Ahmed Shuvro, Pankaz Das, Jamir Shariar Jyoti, Joana Abreu, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

The reliable operation of power grids during cascading failures is heavily dependent on the interdependencies between the power grid components and the supporting communications and control networks. Moreover, the system operators' expertise in dealing with cascading failures can play a pivotal role during contingencies. In this paper, a dynamical probabilistic model is developed based on Markov-chains, which captures the dynamics of cascading failures in the power grid. Specifically, a previously developed Markov-chain based model is extended to capture the trade-off between the benefits of having a robust communication infrastructure and its vulnerability from data integrity (e.g., cyber-attacks). State-space reduction of …

When Intercepting Moving Targets, Mid-Movement Error Corrections Reflect Distinct Responses To Visual And Haptic Perturbations, Pablo Gonzalez Polanco, Leigh A. Mrotek, Kristy A. Nielson, Scott A. Beardsley, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We examined a key aspect of sensorimotor skill: the capability to correct performance errors that arise mid-movement. Participants grasped the handle of a robot that imposed a nominal viscous resistance to hand movement. They watched a target move pseudo-randomly just above the horizontal plane of hand motion and initiated quick interception movements when cued. On some trials, the robot's viscosity or the target's speed changed without warning coincident with the GO cue. We fit a sum-of-Gaussians model to mechanical power measured at the handle to determine the number, magnitude, and relative timing of submovements occurring in each interception attempt. When …

Scan4façade: Automated As-Is Façade Modeling Of Historic High-Rise Buildings Using Drones And Ai, Yuhan Jiang, Sisi Han, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

This paper presents an automated as-is façade modeling method for existing and historic high-rise buildings, named Scan4Façade. To begin with, a camera drone with a spiral path is employed to capture building exterior images, and photogrammetry is used to conduct three-dimensional (3D) reconstruction and create mesh models for the scanned building façades. High-resolution façade orthoimages are then generated from mesh models and pixelwise segmented by an artificial intelligence (AI) model named U-net. A combined data augmentation strategy, including random flipping, rotation, resizing, perspective transformation, and color adjustment, is proposed for model training with a limited number of labels. As …

Planar Compliance Realization With Two 3-Joint Serial Mechanisms, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

In this paper, the realization of any specified planar compliance with two 3R serial elastic mechanisms is addressed. Using the concept of dual elastic mechanisms, it is shown that the realization of a compliant behavior with two serial mechanisms connected in parallel is equivalent to its realization with a 6-spring fully parallel mechanism. Since the spring axes of a 6-spring parallel mechanism indicate the geometry of a dual 3R serial mechanism, a new synthesis procedure for the realization of a stiffness matrix with a 6-spring parallel mechanism is first developed. Then, this result is extended to a geometric construction-based synthesis …

Mitigating Cascading Failures In Power Grids Via Markov Decision-Based Load-Shedding With Dc Power Flow Model, Pankaz Das, Rezoan Ahmed Shuvro, Kassie Povinelli, Francesco Sorrentino, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

Despite the reliability of modern power systems, large blackouts due to cascading failures (CFs) do occur in power grids with enormous economic and societal costs. In this article, CFs in power grids are theoretically modeled proposing a Markov decision process (MDP) framework with the aim of developing optimal load-shedding (LS) policies to mitigate CFs. The embedded Markov chain of the MDP, established earlier to capture the dynamics of CFs, features a reduced state-space and state-dependent transition probabilities. We introduce appropriate actions affecting the dynamics of CFs and associated costs. Optimal LS policies are computed that minimize the expected cumulative cost …

Comparative Study And Design Optimization Of A Dual-Mechanical-Port Electric Machine For Hybrid Electric Vehicle Applications, Hao Chen, Ayman M. El-Refaie, Yuefei Zuo, Shun Cai, Libing Cao, Christopher H. T. Lee

Electrical and Computer Engineering Faculty Research and Publications

A new dual-mechanical-port (DMP) electric machine for hybrid electric vehicle applications, particularly in the power-split continuously variable transmission systems, is proposed in this paper. In order to comprehensively and quantitatively evaluate the pros and cons of the proposed machine, a comparative study of four DMP electric machines with different topologies is conducted. These four investigated DMP electric machines include a conventional DMP machine, a DMP machine with spoke-type permanent magnets, a DMP machine with reluctance rotor, and a DMP machine with open slots which is the proposed machine in this paper. Even though these four machines have similar topologies, they …

Intergrader Agreement Of Foveal Cone Topography Measured Using Adaptive Optics Scanning Light Ophthalmoscopy, Niamh Wynne, Jenna A. Cava, Mina Gaffney, Heather Heitkotter, Abigail Scheidt, Jenny L. Reiniger, Jenna Grieshop, Kai Yang, Wolf M. Harmening, Robert F. Cooper, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

The foveal cone mosaic can be directly visualized using adaptive optics scanning light ophthalmoscopy (AOSLO). Previous studies in individuals with normal vision report wide variability in the topography of the foveal cone mosaic, especially the value of peak cone density (PCD). While these studies often involve a human grader, there have been no studies examining intergrader reproducibility of foveal cone mosaic metrics. Here we re-analyzed published AOSLO foveal cone images from 44 individuals to assess the relationship between the cone density centroid (CDC) location and the location of PCD. Across 5 graders with variable experience, we found a measurement error …

Fluorescein Clearance Kinetics In Blood And Bile Indicates Hepatic Ischemia-Reperfusion Injury In Rats, Joohyun Kim, Yongquiang Yang, Seung-Keun Hong, Jacek Zielonka, Ranjan K. Dash, Said H. Audi, Suresh N. Kumar, Amit Joshi, Michael W. Zimmerman, Johnny C. Hong

Biomedical Engineering Faculty Research and Publications

Quantitative measurement of the degree of hepatic ischemia-reperfusion injury (IRI) is crucial for developing therapeutic strategies for its treatment. We hypothesized that clearance of fluorescent dye through bile metabolism may reflect the degree of hepatic IRI. In this study, we investigated sodium fluorescein clearance kinetics in blood and bile for quantifying the degree of hepatic IRI. Warm ischemia times (WITs) of 0, 30, or 60 min followed by 1 h or 4 h of reperfusion, were applied to the median and lateral lobes of the liver in Sprague-Dawley rats. Subsequently, 2 mg/kg of sodium fluorescein was injected intravenously, and blood …

The Relationship Between Cerebrovascular Reactivity And Cerebral Oxygenation During Hemodialysis, W. T. Richerson, Brian D. Schmit, D. F. Wolfgram

Biomedical Engineering Faculty Research and Publications

Significance Statement

Patients with ESKD have a high burden of ischemic brain lesions related to decline in cerebral blood flow during hemodialysis. Preliminary studies in patients on hemodialysis noted impairment in cerebrovascular reactivity, a mechanism that regulates cerebral perfusion. We found that lower cerebrovascular reactivity was associated with greater decrease in cerebral oxygen saturation during hemodialysis, particularly when accounting for changes in systemic BP. These results suggest that testing cerebrovascular reactivity could be relevant to characterizing risk of cerebral ischemia during hemodialysis and the potential sequelae of brain injury and cognitive impairment over time.

Background

Patients with kidney failure treated …

Identification And Quantitation Of Aqueous Single- And Multianalyte Solutions Of The Isomers Ethylbenzene, M-, P-, And O-Xylene Using A Single Specifically Tailored Sensor Coating And Estimation Theory-Based Signal Processing, Nicholas Post, Florian Bender, Fabien Josse, Edwin E. Yaz, Antonio J. Ricco

Electrical and Computer Engineering Faculty Research and Publications

The isomer-specific detection and quantitation of m-, p-, and o-xylene and ethylbenzene, dissolved singly and as mixtures in aqueous solutions at concentrations from 100 to 1200 ppb by volume, is reported for a specifically designed polymer-plasticizer coating on a shear-horizontal surface acoustic wave (SH-SAW) device. The polystyrene-ditridecyl phthalate-blend coating was designed utilizing Hansen solubility parameters and considering the dipole moment and polarizability of the analytical targets and coating components to optimize the affinity of the sensor coating for the four chemical isomers. The two key coating sorption properties, sensitivity and response time constant, are determined by the …

Electrothermal Design Of A Gan-Based Axially Stator Iron-Mounted Fully Integrated Modular Motor Drive, Armin Ebrahimian, Waqar A. Khan, S. Iman Hosseini, Nathan Weise

Electrical and Computer Engineering Faculty Research and Publications

The concept of More Electric Aircraft (MEA) has gained a lot of attention from researchers recently. For such an application, two of the pivotal requirements are having a power dense and energy efficient propulsion system. To that end, in the design procedure of the electric motor and its drive system, high power density and efficiency over the entire operating range is the ultimate goal. Thus, the integration of the electric motor and drive system into a single unit has been introduced as an effective method to meet the design objectives. Therefore, this paper presents the design procedure of a module …

The Value Of High Intensity Locomotor Training Applied To Patients With Acute-Onset Neurologic Injury, Meghan Fahey, Gabrielle Brazg, Christopher E. Henderson, Abby Plawecki, Emily H. Lucas, Darcy S. Reisman, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

The purpose of this review is to delineate some of the evidence regarding the effects of exercise intensity during locomotor training in patients with stroke and iSCI. We provide specific definitions of exercise intensity used within the literature, describe methods used to ensure appropriate levels of exertion, and discuss potential adverse events and safety concerns during its application. Further details on the effects of locomotor training intensity on clinical outcomes, and on neuromuscular and cardiovascular function will be addressed as available. Existing literature across multiple studies and meta-analyses reveals that exercise training intensity is likely a major factor that can …

Supermodal Decomposition Of The Linear Swing Equation For Multilayer Networks, Kshitij Bhatta, Amirhossein Nazerian, Francesco Sorrentino, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

We study the swing equation in the case of a multilayer network in which generators and motors are modeled differently; namely, the model for each generator is given by second order dynamics and the model for each motor is given by first order dynamics. We also remove the commonly used assumption of equal damping coefficients in the second order dynamics. Under these general conditions, we are able to obtain a decomposition of the linear swing equation into independent modes describing the propagation of small perturbations. In the process, we identify symmetries affecting the structure and dynamics of the multilayer network …

Reduced Chest Computed Tomography Scan Length For Patients Positive For Coronavirus Disease 2019: Dose Reduction And Impact On Diagnostic Utility, Sara Principi, Stacy D. O'Connor, Frank Luba, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Objective

This work aimed to retrospectively evaluate the potential of dose reduction on chest computed tomography (CT) examinations by reducing the longitudinal scan length for patients positive for coronavirus disease 2019 (COVID-19).

Methods

This study used the Personalized Rapid Estimation of Dose in CT (PREDICT) tool to estimate patient-specific organ doses from CT image data. The PREDICT is a research tool that combines a linear Boltzmann transport equation solver for radiation dose map generation with deep learning algorithms for organ contouring. Computed tomography images from 74 subjects in the Medical Imaging Data Resource Center–RSNA International COVID-19 Open Radiology Database data …

Vibrotactile Perception For Sensorimotor Augmentation: Perceptual Discrimination Of Vibrotactile Stimuli Induced By Low-Cost Eccentric Rotating Mass Motors At Different Body Locations In Young, Middle-Aged, And Older Adults, Ella Pomplun, Ashiya Thomas, Erin Corrigan, Valay A. Shah, Leigh A. Mrotek, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Sensory augmentation technologies are being developed to convey useful supplemental sensory cues to people in comfortable, unobtrusive ways for the purpose of improving the ongoing control of volitional movement. Low-cost vibration motors are strong contenders for providing supplemental cues intended to enhance or augment closed-loop feedback control of limb movements in patients with proprioceptive deficits, but who still retain the ability to generate movement. However, it remains unclear what form such cues should take and where on the body they may be applied to enhance the perception-cognition-action cycle implicit in closed-loop feedback control. As a step toward addressing this knowledge …

Seasonal And Spatial Patterns Differ Between Intracellular And Extracellular Antibiotic Resistance Genes In Urban Stormwater Runoff, Kassidy N. O'Malley, Patrick J. Mcnamara, Walter M. Mcdonald

Civil and Environmental Engineering Faculty Research and Publications

Antibiotic resistance is a public health threat that is exacerbated by the dispersion of antibiotic resistance genes (ARGs) into aquatic environments. Urban stormwater runoff has been recognized as a source of and a mechanism by which intracellular ARGs (iARGs) can be transported into receiving environments. The prevalence and behavior of extracellular ARGs (eARGs) in stormwater, however, has yet to be considered. This study quantified four iARGs and eARGs under baseflow and stormflow conditions. Urban stormwater runoff was found to be a source of all the ARGs examined, with the absolute concentration of all iARGs and two eARGs (ermF …

Lab-Scale Data And Microbial Community Structure Suggest Shortcut Nitrogen Removal As The Predominant Nitrogen Removal Mechanism In Post-Aerobic Digestion (Pad), Fabrizio Sabba, Patrick J. Mcnamara, Eric Redmond, Mike Young, Leon Downing

Civil and Environmental Engineering Faculty Research and Publications

Implementing an aerobic digestion step after anaerobic digestion, referred to as “post aerobic digestion” (PAD), can remove ammonia without the need for an external carbon source and destroy volatile solids. While this process has been documented at the lab-scale and full-scale, the mechanism for N removal and the corresponding microbial community that carries out this process have not been established. This research gap is important to fill because the nitrogen removal pathway has implications on aeration requirements and carbon demand, that is, short-cut N-removal requires less oxygen and carbon than simultaneous nitrification–denitrification. The aims of this research were to (i) …

Experimental Study And Piezoresistive Mechanism Of Electrostatic Self-Assembly Of Carbon Nanotubes–Carbon Black/Epoxy Nanocomposites For Structural Health Monitoring, Yanlei Wang, Yao Fu, Ziping Meng, Baolin Wan, Baoguo Han

Civil and Environmental Engineering Faculty Research and Publications

Since electrostatic self-assembly carbon nanotubes–carbon black (CNTs–CB) composite fillers have good electrical conductivity and an easy dispersion process, they were incorporated into epoxy matrix to fabricate the CNTs–CB/epoxy nanocomposites. The mechanical properties, electrical conductivity, piezoresistivity, as well as microstructure characterization of the CNTs–CB/epoxy nanocomposites were experimentally investigated. The piezoresistive mechanisms of the CNTs–CB/epoxy nanocomposites were also established based on tunneling conduction and contacting conduction. The significant improvements in compressive yielding strength and elastic modulus of the nanocomposites could be attributed to the stable interfacial interaction. A moderate percolation threshold was obtained at 0.41 vol% for the CNTs–CB/epoxy nanocomposites in comparison …

Sequential Electrolysis And Reverse Osmosis To Improve Arsenic Removal From Water, Yizhi Hou, Brooke Mayer

Civil and Environmental Engineering Faculty Research and Publications

Reverse osmosis (RO) typically removes >98% arsenate (As[V]) but removes arsenite (As[III]) comparatively poorly (approximately 50%–80%). Therefore, oxidizing As(III) to As(V) can improve arsenic removal using RO. In this study, electrolytic oxidation was used to oxidize As(III) in the feed water, and an extreme low-pressure RO membrane was subsequently used to remove the arsenic. Using Ti/IrO2 electrodes under 30 mA DC current in 500 mg/L NaCl solution primarily generated free chlorine, which completely oxidized 300 μg/L As(III) to As(V). Subsequent arsenic removal by RO increased from 54.2% without oxidation to 98.2% with oxidation. Using electrolysis-RO, arsenic removal significantly increased beyond …

Hepatic Artery Flow, Inspired Oxygen, And Hemoglobin Determine Liver Tissue Saturation Measured With Visible Diffuse Reflectance Spectroscopy (Vis-Drs) In An In Vivo Swine Model, Stylianos Voulgarelis, Faraneh Fathi, Bing Yu, Barbara Palkovic, Nikolaos A. Chatzizacharias, Kenneth P. Allen, Astrid G. Stucke

Biomedical Engineering Faculty Research and Publications

Background

Prompt diagnosis of vascular compromise following pediatric liver transplantation and restoration of oxygen delivery to the liver improves organ survival. vis-DRS allows for real-time measurement of liver tissue saturation.

Methods

The current study used vis-DRS to determine changes in liver saturation during clinically relevant conditions of reduced oxygen delivery. In an in vivo swine model (n = 15), we determined liver tissue saturation (S_tO₂) during stepwise reduction in hepatic artery flow, different inspiratory oxygen fraction (FiO₂), and increasing hemodilution. A custom vis-DRS probe was placed directly on the organ.

Results

Liver tissue …

Poly (5-Carboxyindole)–Β-Cyclodextrin Composite Material For Enhanced Formaldehyde Gas Sensing, John N. Hodul, Nikhil F. Carneiro, Allison K. Murray, Wilson Lee, Kelly M. Brayton, Xinping He, Carsten Flores-Hansen, Dimitry Zemlyanov, George T.-C. Chiu, James E. Braun, Bryan W. Boudouris, Jeffrey F. Rhoads

Mechanical Engineering Faculty Research and Publications

Formaldehyde, a compound commonly employed in many construction materials, paints, and plastics, has been linked to deleterious health effects. Thus, monitoring the presence of formaldehyde in interior locations is increasingly important when it comes to public health. Currently, there is a crucial need for a low-cost, small-scale, selective, and sensitive indoor sensor capable of real-time formaldehyde detection. To meet these performance metrics, materials need to be incorporated onto existing gas sensor platforms to act as chemically selective recognition layers. A main challenge when addressing this issue is creating a material that can remain easily processable, can be easily synthesized, and …