UMBC Chemical, Biochemical & Environmental Engineering Department

Permanent URI for this collectionhttp://hdl.handle.net/11603/49

Faculty in our department focus their research in nine core areas encompassing biological, environmental, and educational research. Our department offers an undergraduate course of study leading to a B.S. in Chemical Engineering through three tracks of study: (i) Traditional Track, (ii) Biotechnology and Bioengineering Track and (iii) Environmental Engineering and Sustainability track. We also offer both M.S. and Ph.D. degrees through two different graduate programs. Details can be found on our website: http://www.umbc.edu/cbe

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Delivery of Tempol from Polyurethane Nanocapsules to Address Oxidative Stress Post-Injury
(ACS, 2025-02-19) Ale, Temitope; Ale, Tolulope; Baker, Kimberly J.; Zuniga, Kameel M.; Hutcheson, Jack; Lavik, Erin
Traumatic brain injuries (TBIs) result in significant morbidity and mortality due to the cascade of secondary injuries involving oxidative stress and neuroinflammation. The development of effective therapeutic strategies to mitigate these effects is critical. This study explores the fabrication and characterization of polyurethane nanocapsules for the sustained delivery of Tempol, a potent antioxidant. The nanocapsules were designed to extend the release of Tempol over a 30-day period, addressing the prolonged oxidative stress observed post-TBI. Tempol-loaded polyurethane nanocapsules were synthesized using interfacial polymerization and nanoemulsion techniques. Two generations of nanocapsules were produced, differing in Tempol loading and PEGylation levels. The first generation, with lower Tempol loading, exhibited an average size of 159.8 � 12.61 nm and a Z-average diameter of 771.9 � 87.95 nm. The second generation, with higher Tempol loading, showed an average size of 141.4 � 6.13 nm and a Z-average diameter of 560.7 � 171.1 nm. The zeta potentials were ?18.9 � 5.02 mV and ?11.9 � 3.54 mV for the first and second generations, respectively. Both generations demonstrated the presence of urethane linkages, confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Loading studies revealed Tempol concentrations of 61.94 � 3.04 ?g/mg for the first generation and 77.61 � 3.04 ?g/mg for the second generation nanocapsules. Release profiles indicated an initial burst followed by a sustained, nearly linear release over 30 days. The higher PEGylation in the second generation nanocapsules is advantageous for intravenous administration, potentially enhancing their therapeutic efficacy in TBI treatment. This study demonstrates the feasibility of using polyurethane nanocapsules for the prolonged delivery of Tempol, offering a promising approach to manage oxidative stress and improve outcomes in TBI patients. Future work will include testing these nanocapsules in vivo to determine their potential at modulating recovery from TBI.
Polyurethane Nanocapsules Incorporating Epigallocatechin Gallate, A Green Tea Extract
(Wiley, 2025-02-26) Ale, Temitope; Ghunney, Nhyira; Pandala, Narendra; Tucker, Budd; McFadden, Kassandra; Hutcheson, Jack; Lavik, Erin
Explosions cause 79% of combat-related injuries, often leading to traumatic brain injury (TBI) and hemorrhage. Epigallocatechin gallate (EGCG), a green tea polyphenol, aids neuroprotection and wound healing. In this work, we sought to investigate the fabrication and characterization of polyurethane nanocapsules encapsulating EGCG, demonstrating controlled, on-demand release, and highlighting their potential for targeted therapeutic delivery in trauma care.
Recent Advances in Wearable Sweat Sensor Development
(Wiley, 2025) Zhang, Tao; Kabandana, Giraso Keza Monia; Terrell, John A.; Chen, Hui; Chen, Chengpeng
Wearable sweat sensors for detecting biochemical markers have emerged as a transformative research area, with the potential to revolutionize disease diagnosis and human health monitoring. Since 2016, a substantial body of pioneering and translational work on sweat biochemical sensors has been reported. This review aims to provide a comprehensive summary of the current state-of-the-art in the field, offering insights and perspectives on future developments. The focus is on wearable microfluidic platforms for sweat collection and delivery and the analytical chemistry applicable to wearable devices. Various microfluidic technologies, including those based on synthetic polymers, paper, textiles, and hydrogels, are discussed alongside diverse detection methods such as electrochemistry and colorimetry. Both the advantages and current limitations of these technologies are critically examined. The review concludes with our perspectives on the future of wearable sweat sensors, with the goal of inspiring new ideas, innovations, and technical advancements to further the development and practical application of these devices in promoting human health.
Bridging the Gap: At-Home Experiments Connecting Theory and Practice in Chemical Engineering Education
(ASEE, 2024) Das, Gautom K.
The 2022 report by the National Academies of Sciences, Engineering, and Medicine urged a greater focus on experimental learning to bridge core course silos. ABET also requires students to design and conduct experiments, analyze data, and draw conclusions by graduation. However, the packed engineering curriculum challenges additional hands-on lab courses. To address this, we explored an idea to extend learning beyond traditional settings. Inspired by the American Chemical Society's guidelines, we aimed to study at-home experiments for connecting experiments to theories and investigated if students could independently design experiments at home, aligning with the senior chemical engineering laboratory course's objectives. Students spent four weeks conducting at-home experiments and self-evaluated their learning outcomes. Results indicated positive attitudes and their enthusiastic time investment. The at-home projects enhanced learning, fostered critical thinking, and aligned with evolving engineering education priorities. In future iterations, we plan to allocate more time and extend project timelines for greater learning experience.
Climatology of aerosol pH and its controlling factors at the Melpitz continental background site in central Europe
(EGU, 2025-02-10) Pratap, Vikram; Hennigan, Christopher; Stieger, Bastian; Tilgner, Andreas; Poulain, Laurent; van Pinxteren, Dominik; Spindler, Gerald; Herrmann, Hartmut
Aerosol acidity has importance for the chemical and physical properties of atmospheric aerosol particles and for many processes that affect their transformations and fate. Here, we characterize trends in aerosol pH and its controlling factors over the period of 2010 ? 2019 at the Melpitz research station in eastern Germany, a continental background site in central Europe. Aerosol liquid water content (ALWC) decreased by 50 % during the analyzed time period in response to decreasing sulfate and nitrate. Aerosol pH exhibited an increase of 0.06 units per year, a trend that was distinct from other regions. Seasonal analysis showed strong variability in factors controlling aerosol pH. Temperature, the most important factor driving pH variability overall, was most important in summer (responsible for 51 % of pH variability) and less important during spring and fall (22 % and 27 %, respectively). NH3, the second most important factor contributing to pH variability overall (29 %), was most important during winter (38 %) and far less important during summer (15 %). Aerosol chemistry in Melpitz is influenced by the high buffering capacity contributed by NH4+/NH3 and, to a lesser degree, NO3-/HNO3. Thermodynamic analysis of the aerosol system shows that secondary inorganic aerosol formation is most frequently HNO3 limited, suggesting that NOx controls would be more effective than NH3 controls in reducing PM mass concentrations. However, the non-linear response of gas-phase HNO3 and aerosol NO3- to NOx emissions in the region highlights the challenge associated with PM reductions needed to attain new air quality standards in this region.
Microdroplet-enabled high-throughput cultivation of vaginal bacteria using cervicovaginal fluids
(2023-09-26) Jackman, Corine; Tan, James Y.; Lin, Xiaoxia Nina
The human vaginal microbiome (HVM) is closely associated with the health of the host. In particular, bacterial vaginosis, a condition where vaginal lactobacilli are reduced dramatically by an overgrowth of various other bacteria, has been linked to increased risk of sexually transmitted infectious diseases, including HIV, and preterm birth. Recent culture-independent studies leveraging next-generation sequencing technology have revealed that the HVM composition differs between women and changes over time. However, questions remain as to the underlying mechanisms and culture-dependent studies are needed for further elucidation of the HVM’s genotype-phenotype relationships and system-level properties in vivo. In this work, we have adapted a previously developed microdroplet-based high-throughput cultivation platform for the investigation of vaginal bacteria using the cervicovaginal fluid (CVF) as cultivation medium. Using undiluted CVF collected with Softdiscs discs, we observed the growth of L. iners in microdroplets containing CVF pooled from samples with a high prevalence of L. crispatus. Although demonstrated with L. iners, this work establishes a new framework for culturing microorganisms under clinically-relevant conditions ex vivo using minute volumes of host fluids; it can be further extended and adapted for addressing numerous questions about the HVM and other complex microbiomes.
Development and Optimization of Passive Sampling Methods for Surface Water and Sediment Porewater Measurements of Freely Dissolved Concentrations of Hydrophobic Organic Contaminant
(2024-01-01) Ghosh, Oindrila; Ghosh, Upal; Chemical, Biochemical & Environmental Engineering; Engineering, Civil and Environmental
Polychlorinated biphenyls (PCBs) are hydrophobic organic contaminants (HOCs) that have persisted in the environment for decades after production was banned by the USEPA in 1979. PCBs are known carcinogens and bioaccumulate into organisms through the aquatic food web, thereby posing threats to ecological and human health even at trace concentrations in the environment. The freely dissolved concentration in the aqueous phase (Cfree) is a useful indicator of chemical activity and is critical to determine exchange between environmental phases and bioaccumulation in organisms. Polymeric passive sampling (PS) provides time- integrated Cfree measurements in surface waters and sediment porewaters, unlike grab sampling that provides a snapshot of the concentration at one point in time. The primary objectives of this research were: (1) to understand the true nature of the time-integrative property of equilibrium PS under fluctuating ambient surface water concentrations, (2) to design PS devices (by manipulating their major rate-limiting zones for mass transfer so that approach to equilibrium is expedited) and develop field demonstrated PS prototypes that can perform (i) short-term measurements of HOCs in surface water during a storm event or (ii) address the challenges associated with Cfree porewater measurements for strongly hydrophobic compounds, (3) to develop standardized methods for impregnating performance reference compounds (PRCs) into PS (that helps determining the extent of a sampler’s approach to equilibrium) and calculating the cost of preparing PRC impregnated low density polyethylene (LDPE) samplers. The theoretical and modeling framework of exchange kinetics in PS developed in this study, was utilized to calculate sampling time scale of integration (TSI) and sensitivity (%) for various chemical-sampler pairs. This was used to develop and optimize the designs of PS devices for long- and short-term deployments in the field for accurate pore-water and surface water Cfree measurements. In high flow conditions, when diffusion is controlled by the sampler side, thin sheet PS (18 ?m PE) were used to perform short-term Cfree measurements over a stormflow event lasting for 42 hours in a PCB contaminated tributary to an urban river in Washington DC. Results indicated evidence of the tributary as a major source of PCB loading to the main river during stormflow conditions. In compact sediments, diffusion is controlled by the water boundary layer (WBL) external to the sampler. Mechanical disruption of the WBL outside the sampler by introducing periodic vibration on field demonstrated sampling devices showed that within compact sediments, PS reached at least 20% equilibrium in 8 days even for the more hydrophobic PCBs and dioxins/furans, as demonstrated by the depletion of PRCs from the samplers. Accurate measurements of Cfree in sediment porewater was possible by performing PRC corrections. Non homogenous PRC loading can lead to error prone estimations of fractional PRC losses used for correcting for non-equilibrium conditions. PRC stock solutions in nonane when spiked in methanol-water systems, homogenous impregnations of LDPE with overall RSD 4% was observed. The material-cost of preparing 1 g of LDPE at 200 ng/g from 80:20 methanol-water solutions was approximately $8.
Modeling time scale of integration in equilibrium passive sampling
(Oxford University Press, 2025-01-06) Ghosh, Oindrila; Yan, Songjing; Bokare, Mandar; Ghosh, Upal
Passive samplers (PSs) deployed in the field for several months provide a time-averaged measurement of the freely dissolved concentration of pollutants, which is important for assessing ecological exposure and estimating pollutant loads. A comprehensive theoretical modeling assessment of the sampling time scale of integration (TSI) of an equilibrium PS is required to correctly interpret the results. We address this knowledge gap by modeling exchange kinetics of polychlorinated biphenyl congeners in low-density polyethylene (PE) PS based on diffusive transport and first-order kinetics. We evaluate the sampling TSI by analyzing the response of the PS to simulated pulsed concentration increases in the water column that lasted for 1 day in a total sampling period of 90 days. More hydrophobic compounds experience slower transfer into the sampler and show a longer TSI compared with less hydrophobic compounds. Similarly, a thick sampler shows longer TSI than a thinner sampler. The sampling TSI for a typical 25.4 ?m PE sheet ranged widely from 14� days for a dichlorobiphenyl to 43� days for a hexachlorobiphenyl. We show that strategic deployment of a thick and thin passive sampler can be used to narrow the range of TSIs for all congeners and used to simultaneously capture episodic events along with long-term averages.
Current Strategies and Future Directions of Wearable Biosensors for Measuring Stress Biochemical Markers for Neuropsychiatric Applications
(Wiley, 2024-12-17) Sheffield, Zach; Paul, Priyanka; Krishnakumar, Shraddha; Pan, Prof Dipanjan
Most wearable biosensors aimed at capturing psychological state target stress biomarkers in the form of physical symptoms that can correlate with dysfunction in the central nervous system (CNS). However, such markers lack the specificity needed for diagnostic or preventative applications. Wearable biochemical sensors (WBSs) have the potential to fill this gap, however, the technology is still in its infancy. Most WBSs proposed thus far target cortisol. Although cortisol detection is demonstrated as a viable method for approximating the extent and severity of psychological stress, the hormone also lacks specificity. Multiplex WBSs that simultaneously target cortisol alongside other viable stress-related biochemical markers (SBMs) can prove to be indispensable for understanding how psychological stress contributes to the pathophysiology of neuropsychiatric illnesses (NPIs) and, thus, lead to the discovery of new biomarkers and more objective clinical tools. However, none target more than one SBM implicated in NPIs. Till this review, cortisol's connection to dysfunctions in the CNS, to other SBMs, and their implication in various NPIs has not been discussed in the context of developing WBS technology. As such, this review is meant to inform the biosensing and neuropsychiatric communities of viable future directions and possible challenges for WBS technology for neuropsychiatric applications.
Chloride Interferences in Wet Chemical Oxidation Measurements: Plausible Mechanisms and Implications
(ACS, 2024-12-04) Chiu, Yin Ting T.; Burns, Alyssa M.; Rosanka, Simon; Hu, Tiffany; Hennigan, Christopher; Carlton, Annmarie G.
Wet chemical oxidation (WCO) methods measure total organic carbon (TOC) in aqueous solutions through the formation and detection of carbon dioxide (CO₂). Prior research documents chloride (Cl⁻) interference during WCO. However, the mechanism that determines WCO interference is not established. We investigate WCO and find that formic acid exhibits TOC recovery (89–108%) within measurement uncertainty in the presence of Cl⁻, while acetic acid recovery is substantially reduced (3–67%). We postulate that chlorine radical (•Cl) formation during WCO alters oxidation pathways for organic compounds with methyl groups to form stable halogenated organic species that are thus not detected as CO₂, reducing observed TOC recovery. We develop a kinetic model of elementary step reactions that reproduces observed TOC recoveries at multiple organic (1 and 5 ppm of C) and Cl⁻ (>0.01 M) concentrations for both acetic and formic acids. Independent experiments with pyruvic acid and different halogen salts are consistent with the proposed mechanism. Our findings provide a plausible mechanistic explanation for Cl⁻ interference in WCO-derived TOC measurements of environmental samples for which halogenated salts are present. A plausible mechanism provides a more complete understanding of how and why the TOC is biased low in environmental aquatic samples from saline environments when WCO is employed.
Advancing Cell-Free Manufacturing: Challenges in Scale-up and Automation Workshop Report
(NIST, 2024-11-20) Romantseva, Eugenia; Oliveira, Fernanda Piorino Macruz de; Sundberg, Chad Alan; Sittampalam, G. Sitta; Strychalski, Elizabeth
The National Institute of Standards and Technology (NIST) and the National Center for Advancing Translational Sciences (NCATS) convened the workshop Advancing Cell-free Manufacturing: Challenges in Scale-up and Automation in Rockville, Maryland in February 2024. This workshop brought together over fifty participants, representing the interests and needs of stakeholders in academic, industrial, and government settings. Together, through various plenary discussions, case studies, and working groups, participants broadly surveyed the field and focused on identifying both near-term and long-term needs to support cell-free expression systems. This report synthesizes the workshop discussion and presents actionable recommendations aimed at removing the remaining barriers to realizing the full impact of CFE systems on biomanufacturing and applications of biotechnology.
In Context Learning and Reasoning for Symbolic Regression with Large Language Models
(2024-10-22) Sharlin, Samiha; Josephson, Tyler R.
Large Language Models (LLMs) are transformer-based machine learning models that have shown remarkable performance in tasks for which they were not explicitly trained. Here, we explore the potential of LLMs to perform symbolic regression -- a machine-learning method for finding simple and accurate equations from datasets. We prompt GPT-4 to suggest expressions from data, which are then optimized and evaluated using external Python tools. These results are fed back to GPT-4, which proposes improved expressions while optimizing for complexity and loss. Using chain-of-thought prompting, we instruct GPT-4 to analyze the data, prior expressions, and the scientific context (expressed in natural language) for each problem before generating new expressions. We evaluated the workflow in rediscovery of five well-known scientific equations from experimental data, and on an additional dataset without a known equation. GPT-4 successfully rediscovered all five equations, and in general, performed better when prompted to use a scratchpad and consider scientific context. We also demonstrate how strategic prompting improves the model's performance and how the natural language interface simplifies integrating theory with data. Although this approach does not outperform established SR programs where target equations are more complex, LLMs can nonetheless iterate toward improved solutions while following instructions and incorporating scientific context in natural language.
Targeted K-Edge Nanoprobes From Praseodymium and Hafnium for Ratiometric Tracking of Dual Biomarkers using Spectral Photon Counting CT
(Wiley, 2024-10-07) Gunaseelan, Nivetha; Moitra, Parikshit; Saha, Pranay; Aditya, Teresa; Moghiseh, Mahdieh; Jonker, Kevin; Gieseg, Steven; Butler, Anthony; Kamal, Fadia; Pan, Prof Dipanjan
Utilizing metal nanoprobes with unique K-edge identities to visualize complementary biological activities simultaneously can provide valuable information about complex biological processes. This study describes the design and preparation of an innovative pair of K-edge metal nanoprobes and demonstrates the feasibility of their simultaneous quantitative detection using spectral photon-counting computed tomography (SPCCT). Glycosaminoglycan (GAG) capped nanoparticles (ca. 15–20 nm) targeting two distinct components of the cartilage tissue, namely, aggrecan (acan) and aggrecanase (acanase) are designed and synthesized. These targeted nanoparticles comprised of praseodymium (Pr) and hafnium (Hf), with well-separated K-edge energies, enable simultaneous and ratiometric imaging of dual biomarkers in cartilage tissue. Following extensive physico-chemical characterization of the ligand-targeted particles, the feasibility of homing dual biomarkers in vitro is demonstrated. The material discrimination and simultaneous quantification of these targeted particles are also achieved and corroborated with inductively coupled plasmon spectroscopy. For the first time, the use of praseodymium is reported as a contrast agent for SPCCT imaging and demonstrates the ability to pair it with hafnium nanoprobes for multicontrast imaging of diseases. Importantly, the potential for ratiometric molecular imaging and tracking of osteoarthritis (OA) progression is shown with SPCCT K-edge based imaging approach.
Lee Blaney Assumes Presidency Of The Association Of Environmental Engineering And Science Professors
(UMBC News, 2024-09-16) Meyers, Catherine; Demond, Marlayna
Professor Lee Blaney, in the Department of Chemical, Biochemical, and Environmental Engineering, formally assumed the role of president of the Association of Environmental Engineering and Science Professors (AEESP) at a board of directors meeting in early September. AEESP is a nonprofit organization founded in 1963 to foster inclusive connections between environmental engineering and science researchers and educators. It provides programs for members to develop the academic networks and career skills needed for professional success, increase equitable societal impact of environmental engineering and science scholarship and creative expression, and reimagine the skills necessary for environmental engineers and scientists to provide solutions… Continue Reading Lee Blaney assumes presidency of the Association of Environmental Engineering and Science Professors
Incremental Inverse Design of Desired Soybean Phenotypes
(ACS, 2024-09-30) Zavorskas, Joseph; Edwards, Harley; Marten, Mark; Harris, Steven; Srivastava, Ranjan
We present an application of computational inverse design, which reverses the conventional trial-and-error forward design paradigm, optimizes biological phenotype by directly modifying genotype. The limitations of inverse design in genotype-to-bulk phenotype (G-BP) mapping can be addressed via an established design paradigm: “design, build, test, learn” (DBTL), where computational inverse design automates both the design and learn phases. In any context, inverse design is limited by the fundamental “one-to-many” nature of the inverse function. G-BP inverse design is further limited by the number of single nucleotide polymorphisms that can be made to a member of the population while maintaining feasibility of genotype creation and biological viability. Considering these limitations, we propose a design paradigm based on incremental optimization of phenotype through a combined computational and experimental approach. We intend this work to be a foundational synthesis of well-known techniques applied to the context of genotype-to-bulk phenotype inverse design, which has not yet been performed in the literature. The design pipeline can optimize phenotype by either directly proposing genotypic changes, or simply by suggesting parents to be used for selective breeding. The soybean nested association matrix data set is used to present an in silico case study of the design pipeline by performing optimization that maximizes protein content while constraining other phenotypes. A random forest (RF) is used to model the genotype-to-phenotype relationship, and a genetic algorithm is used to query the RF until a feasible genotype with desired phenotype is discovered. After 20 in silico DBTL cycles, a final population of individuals with a mean protein content of 36.13%, an increase of three standard deviations above the original mean is suggested.
Completely noninvasive multi-analyte monitoring system for cell culture processes
(Springer, 2024-08-20) Rahmatnejad, Vida; Tolosa, Michael; Ge, Xudong; Rao, Govind
Although online monitoring of dissolved O₂, pH, and dissolved CO₂ is critical in bioprocesses, nearly all existing technologies require some level of direct contact with the cell culture environment, posing risks of contamination. This study addresses the need for an accurate, and completely noninvasive technique for simultaneous measurement of these analytes. A “non-contact” technique for simultaneous monitoring of dissolved O₂, pH, and dissolved CO₂ was developed. Instead of direct contact with the culture media, the measurements were made through permeable membranes via either a sampling port in the culture vessel wall or a flow cell. The efficacy of the “non-contact” technique was validated in Escherichia coli (E.coli), Chinese hamster ovary (CHO) culture processes, and dynamic environments created by sparging gases in cell culture medium. The measurements obtained through the developed techniques were comparable to those obtained through control methods. The noninvasive monitoring system can offer accurate, and contamination-minimized monitoring of critical process parameters including dissolved O₂, pH, and dissolved CO₂. These advancements will enhance the control and optimization of cell culture processes, promising improved cell culture performance.
Impact of Confinement within a Hydrogel Mesh on Protein Thermodynamic Stability and Aggregation Kinetics
(ACS, 2024-01-26) Ghassemi, Zahra; Leach, Jennie B.
Though protein stability and aggregation have been well characterized in dilute solutions, the influence of a confining environment that exists (e.g., in intercellular and tissue spaces and therapeutic formulations) on the protein structure is largely unknown. Herein, the effects of confinement on stability and aggregation were explored for proteins of different sizes, stability, and hydrophobicity when encapsulated in hydrophilic poly(ethylene glycol) hydrogels. Denaturation curves show linear correlations between confinement size (mesh size) and thermodynamic stability, i.e., unfolding free energy and surface area accessible for solvation (represented by m-value). Two clusters of protein types are identifiable from these correlations; the clusters are defined by differences in protein stability, surface area, and aggregation propensity. Proteins with higher stability, larger surface area, and lower aggregation propensity (e.g., lysozyme and myoglobin) are less affected by the confinement imposed by mesh size than proteins with lower stability, smaller surface area, and higher aggregation propensity (e.g., growth hormone and aldehyde dehydrogenase). According to aggregation kinetics measured by thioflavin T fluorescence, confinement in smaller mesh sizes resulted in slower aggregation rates than that in larger mesh sizes. Compared to that in buffer solution, the confinement of a hydrophobic protein (e.g., human insulin) in the hydrogels accelerates protein aggregation. Conversely, the confinement of a hydrophilic protein (e.g., human amylin) in the hydrogels decelerates or prevents aggregation, with the rates of aggregation inversely proportional to mesh size. These findings provide new insights into protein conformational stability in confined microenvironments relevant to various cellular, tissue, and therapeutics scenarios.
POLYCYCLIC AROMATIC HYDROCARBON-INDUCED DISRUPTION OF ENDOTHELIAL PERMEABILITY
(2024-01-01) Patel, Shreyas; Leach, Jennie; Chemical, Biochemical & Environmental Engineering; Engineering, Chemical and Biochemical
Endothelial cells line the interior of vasculature and regulate nutrient exchange while preventing harmful compounds from invading surrounding tissue. Adherens and tight junctions form intercellular junctions that maintain cell-cell adhesion and regulate solute flux between systemic circulation and tissue. These intercellular junctions can be disrupted following exposure to polycyclic aromatic hydrocarbons (PAHs), causing increased permeability in the endothelial barrier. PAHs are ubiquitous pollutants in our surroundings as a consequence of rapid industrialization and heavy reliance on carbon-based fuels. PAH exposure is associated with a myriad of adverse health effects, ranging from skin and eye irritation to cardiovascular disease and cancer. Herein, the permeability of bovine pulmonary artery endothelial cells was examined in vitro following exposure to low molecular weight PAHs. Bovine endothelial barriers demonstrated an average, but not statistically significant, increase in permeability in fluorescein flux assays following exposure to naphthalene, anthracene, and pyrene. The presented data suggests these low molecular weight PAHs can exert an effect on endothelial barrier integrity and function but warrants further optimization to permeability assays and supplemental methods to elucidate the consequences of PAH exposure.
Effects of Inorganic Salts and pH on the Gas-Water Partitioning of Formic Acid and Acetic Acid Observed using Mist Chambers
(2024-01-01) Taylor, Rose; Hennigan, Christopher; Chemical, Biochemical & Environmental Engineering; Engineering, Chemical and Biochemical
Secondary organic aerosol (SOA) is harmful to human health and contributes largeuncertainties to climate forcing. Oxygenated volatile organic compounds (OVOCs), such as carboxylic acids, make significant contributions to SOA by partitioning to atmospheric particulate and aqueous phases. Inorganic salt content and pH of atmospheric water can impact OVOC partitioning and therefore the composition and abundance of SOA. In this work, parallel sampling mist chambers (MC) coupled with wet chemical oxidation(WCO)-based total organic carbon (TOC) analysis is critically evaluated as a method for measuring effects from inorganic salts and pH on formic acid (FA) and acetic acid (AA) gas-water partitioning. High ionic concentrations of chloride (>0.01 mol kg -1 ) and sulfate (>0.1 mol kg -1 ) caused TOC measurement artifacts that required correction. Chloride concentrations characteristic to atmospheric aqueous phases exhibited a salting-out effect on FA and AA partitioning and partitioning to solutions of low pH was reduced. Sulfate did not show a stronginfluence over FA and AA partitioning. Preliminary experiments with glyoxal indicate no effects from chloride and sulfate on partitioning although salting-in effects are reported in literature. Options for further experimentation, validation, and optimization of the MC-WCO method are discussed.
Flux growth of optical sensor zinc selenide crystals
(SPIE, 2024-06-06) Brandt, Meghan; Schmidt, Nicholas; Tauraso, Aria; Sood, Rachit; Su, Ching Hua; Arnold, Bradley; Choa, Fow-Sen; Cullum, Brian; Singh, Narsingh
Binary and ternary selenide crystals have been proven as multifunctional for optical sensors and laser applications. The aim of this study was to evaluate reactive flux growth process of the doped zinc selenide crystals and compared with bulk Physical Vapor Transport (PVT) grown large single crystals. The experimental process of synthesis involved PVP (Polyvinyl Pyrrolidone) flux dissolved in DI water which was heated at 65°C, stirred until all PVP dissolved. We added Se powder dissolved in ethanol and heated again for few minutes. We added ZnCl₂ solution in ethanol/Se mixture and heated at well below 100 ⁰C. Water and ethanol solvent was separated and placed at 200C. The residue material was doped with transition metal. This material was characterized for the luminescence and compared with the results of bulk crystals grown by PVD process.

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