Comprehensive compilation of congener profiles to support health assessment of environmental exposures to polychlorinated biphenyl mixtures.

Exposure to polychlorinated biphenyls (PCBs) remains a potential human health risk due to their persistence in the environment, despite a global ban on their production. Understanding the composition of PCB mixtures is essential for the application of a mixtures-based approach to assessing health risks of PCB exposure. This work represents the most extensive effort to date to compile and make publicly available the PCB congener profiles for mixtures with toxicological data, providing a foundation for understanding toxicological potency of PCB mixtures in the environment.

Concentrations of Volatile Methyl Siloxanes in New York City Reflect Emissions from Personal Care and Industrial Use.

Volatile methyl siloxanes (VMS) are a group of organosilicon compounds of interest because of their potential health effects, their ability to form secondary organic aerosols, and their use as tracer compounds. VMS are emitted in the gas-phase from using consumer and personal care products, including deodorants, lotions, and hair conditioners. Because of this emission route, airborne concentrations are expected to increase with population density, although there are few studies in large urban centers.

LOCALIZED MYOSITIS AND TRANSIENT ENCEPHALOPATHY AS PRESENTING SYMPTOMS IN MURINE TYPHUS.

Murine typhus in the pediatric population has increased substantially in recent years. The most common clinical presentation of murine typhus includes fever, rash, headaches and myalgias. Murine typhus presenting with predominant myositis and/or encephalopathy is rare.

A Survey Study of Motivators for Pediatric Hospitalists to Work in the Community.

Background And Objective: The loss of pediatric beds in the community has contributed to decreased access to pediatric inpatient and emergency services. Community pediatric hospitalist programs could reduce the overhead of inpatient care, promoting the financial feasibility of caring for hospitalized children closer to home. This study aims to determine which career motivators are the most important for pediatric hospitalists to begin working in, remain in, and leave the community setting.

Congener-Specific Emissions from Floors and Walls Characterize Indoor Airborne Polychlorinated Biphenyls.

To reconcile the federal regulation of material polychlorinated biphenyl (PCB) concentrations with recently implemented state regulations of airborne PCBs, there is a need to characterize the relationship between PCB emissions from surfaces and air concentrations. We hypothesized that the magnitude and congener distribution of emissions from floors and walls fully account for the airborne PCBs measured in rooms constructed during the height of PCB production and sales. We measured emissions of PCB congeners from various wall and floor materials using polyurethane foam passive emission samplers before and after hexane wiping.

Polyurethane Foam Emission Samplers to Identify Sources of Airborne Polychlorinated Biphenyls from Glass-Block Windows and Other Room Surfaces in a Vermont School.

We hypothesized that emissions of polychlorinated biphenyls (PCBs) from Aroclor mixtures present in building materials explain their concentrations in school air. Here, we report a study of airborne concentrations and gas-phase emissions in three elementary school rooms constructed in 1958. We collected airborne PCBs using polyurethane foam passive air samplers (PUF-PAS, = 6) and PCB emissions from building materials using polyurethane foam passive emission samplers (PUF-PES, = 17) placed over flat surfaces in school rooms, including vinyl tile floors, carpets, painted bricks, painted drywall, and glass-block windows.

Impact of COVID-19 on the Sense of Job Security Among Community Pediatric Hospitalists.

Objectives: The coronavirus disease 2019 (COVID-19) pandemic offers a prime opportunity to examine the ability of community pediatric hospital medicine programs to respond to external stressors. This study aims to characterize the impact of the COVID-19 pandemic on compensation and furlough among community pediatric hospitalists, as well as self-reported sense of job security.

Methods: This study was part of a larger quantitative project investigating community pediatric hospitalists' career motivators.

Lab-scale biodegradation assay using passive samplers to determine microorganisms' ability to reduce polychlorinated biphenyl (PCB) volatilization from contaminated sediment.

Many PCB-degrading aerobes have been identified which may serve as bioaugmentation strains for aerobic, in situ bioremediation or in combination with dredging operations. The present work describes a lab-scale PCB biodegradation assay which can be used to screen potential bioaugmentation strains or consortia for their ability to decrease PCB mass flux from contaminated sediment to air through biodegradation of freely dissolved PCBs that have desorbed from sediment particles. The assay uses two types of passive samplers to simultaneously measure PCB mass that is freely dissolved in aqueous solution and PCB mass that has volatilized to the headspace of the bioreactor.

Machine Learning-Assisted Identification and Quantification of Hydroxylated Metabolites of Polychlorinated Biphenyls in Animal Samples.

Laboratory studies of the disposition and toxicity of hydroxylated polychlorinated biphenyl (OH-PCB) metabolites are challenging because authentic analytical standards for most unknown OH-PCBs are not available. To assist with the characterization of these OH-PCBs (as methylated derivatives), we developed machine learning-based models with multiple linear regression (MLR) or random forest regression (RFR) to predict the relative retention times (RRT) and MS/MS responses of methoxylated (MeO-)PCBs on a gas chromatograph-tandem mass spectrometry system. The final MLR model estimated the retention times of MeO-PCBs with a mean absolute error of 0.

Epidemiology and variability in management of acute mastoiditis in children.

Background: To evaluate the epidemiology, management and outcome of acute mastoiditis (AM) in children and to improve strategies for antimicrobial stewardship.

Methods: We conducted a retrospective observational study of children aged >6 months to ≤18 years of age admitted to a tertiary care hospital with AM over an 8-year period (2011-2019). Electronic medical records were reviewed to collect data.

Assessment of Polychlorinated Biphenyls and Their Hydroxylated Metabolites in Postmortem Human Brain Samples: Age and Brain Region Differences.

Exposure to polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) has been implicated in neurodevelopmental disorders. However, the distribution of PCBs and OH-PCBs in the human brain has not been characterized. This study investigated the age-, sex-, and brain region-specific distribution of all 209 PCBs using gaschromatography-tandem mass spectrometry (GC-MS/MS) in neonatal ( = 7) and adult ( = 7) postmortem brain samples.

PCB Sulfates in Serum from Mothers and Children in Urban and Rural U.S. Communities.

Serum samples from 24 subjects (6 mother-daughter and 6 mother-son dyads) in a rural community (Columbus Junction, Iowa) and 24 subjects (6 mother-daughter and 6 mother-son dyads) in an urban community (East Chicago, Indiana) were analyzed for 74 sulfated metabolites of polychlorinated biphenyls (PCBs). We detected significantly higher mean concentrations of total assessed PCB sulfates in the urban group (110-8900 ng/g fresh weight of serum, mean = 3400 ng/g, standard error = 300) than in the rural cohort (530-6700 ng/g fresh weight of serum, mean = 1800 ng/g, standard error = 500). Eight PCB sulfate congeners (4-PCB 2 sulfate, 4'-PCB 2 sulfate, 2'-PCB 3 sulfate, 4'-PCB 3 sulfate, 4-PCB 11 sulfate, 4'-PCB 18 sulfate, 4'-PCB 25 sulfate, and 4-PCB 52 sulfate) contributed over 90% of the total assessed PCB sulfates in most individuals.

Room-to-Room Variability of Airborne Polychlorinated Biphenyls in Schools and the Application of Air Sampling for Targeted Source Evaluation.

Airborne polychlorinated biphenyl (PCB) concentrations are higher indoors than outdoors due to their historical use in building materials and their presence in modern paints and surface treatments. For some populations, including school children, PCB levels indoors result in inhalation exposures that may be greater than or equivalent to exposure through diet. In a school, PCB exposure may come from multiple sources.

Dataset describing biodegradation of individual polychlorinated biphenyl congeners (PCBs) by LB400 in presence and absence of sediment slurry.

This dataset describes the biodegradation of polychlorinated biphenyl (PCB) congeners by LB400 in absence and presence of PCB-contaminated sediment slurry, over time [1]. In absence of sediment, PCBs were extracted from aqueous bioreactors by liquid-liquid extraction (LLE) with hexane. In presence of sediment, the extraction method used was a modification of U.

Detection and Quantification of Polychlorinated Biphenyl Sulfates in Human Serum.

Polychlorinated biphenyls (PCBs) are persistent toxic chemicals with both legacy sources (e.g., Aroclors) and new sources (e.

Biodegradation of PCB congeners by Paraburkholderia xenovorans LB400 in presence and absence of sediment during lab bioreactor experiments.

Experiments were conducted to measure biodegradation of polychlorinated biphenyl (PCB) congeners contained in mixture Aroclor 1248 and congeners present in wastewater lagoon sediment contaminated decades earlier at Altavista, Virginia. A well-characterized strain of aerobic PCB-degrading bacteria, Paraburkholderia xenovorans LB400 was incubated in laboratory bioreactors with PCB-contaminated sediment collected at the site. The experiments evaluated strain LB400's ability to degrade PCBs in absence of sediment and in PCB-contaminated sediment slurry.

Signal Processing Methods to Interpret Polychlorinated Biphenyls in Airborne Samples.

The main contribution of this interdisciplinary work is a robust computational framework to autonomously discover and quantify previously unknown associations between well-known (target) and potentially unknown (non-target) toxic industrial air pollutants. In this work, the variability of polychlorinated biphenyl (PCB) data is evaluated using a combination of statistical, signal processing, and graph-based informatics techniques to interpret the raw instrument signal from gas chromatography-mass spectrometry (GC/MS/MS) data sets. Specifically, minimum mean-squared techniques from the adaptive signal processing literature are extended to detect and separate coeluted (overlapped) peaks in the raw instrument signal.

Polychlorinated Biphenyls in Food.

We measured the concentrations of 205 polychlorinated biphenyl (PCB) congeners in 26 food items: beef steak, butter, canned tuna, catfish, cheese, eggs, french fries, fried chicken, ground beef, ground pork, hamburger, hot dog, ice cream, liver, luncheon meat, margarine, meat-free dinner, milk, pizza, poultry, salmon, sausage, shrimp, sliced ham, tilapia, and vegetable oil. Using Diet History Questionnaire II, we calculated the PCB dietary exposure in mothers and children participating in the AESOP Study in East Chicago, Indiana, and Columbus Junction, Iowa. Salmon had the highest concentration followed by canned tuna, but fish is a minor contributor to exposure.

Polymeric Nanofiber-Carbon Nanotube Composite Mats as Fast-Equilibrium Passive Samplers for Polar Organic Contaminants.

To improve the performance of polymeric electrospun nanofiber mats (ENMs) for equilibrium passive sampling applications in water, we integrated two types of multiwalled carbon nanotubes (CNTs; with and without surface carboxyl groups) into polyacrylonitrile (PAN) and polystyrene (PS) ENMs. For 11 polar and moderately hydrophobic compounds (-0.07 ≤ log ≤ 3.

Physical properties of secondary photochemical aerosol from OH oxidation of a cyclic siloxane.

Cyclic volatile methyl siloxanes (cVMS) are high-production chemicals present in many personal care products. They are volatile, hydrophobic, and relatively long-lived due to slow oxidation kinetics. Evidence from chamber and ambient studies indicates that oxidation products may be found in the condensed aerosol phase.

Career Motivators for Community Pediatric Hospitalists.

Background And Objectives: Within the field of pediatric hospital medicine, physicians can choose to work at community-based or university-based centers. The factors that motivate pediatric hospitalists to work specifically at community sites have not yet been fully explored. Our objective with this study was to elucidate the motivators for pediatric hospitalists to begin and continue work at community sites.