Oil sands process-affected water composition effect on Henry's law constants for polycyclic aromatic compounds: Theory and experiment.

Oil sands process-affected water (OSPW) is a source of atmospheric emission for polycyclic aromatic compounds (PACs), compounds known to have toxic effects on humans. Estimating emissions and assessing the chemical fate of PACs requires measured or predicted physical-chemical properties such as Henry's law constants (H), that can be used to predict chemical transfer into the atmosphere. OSPW is a complex water-based mixture that is highly variable in composition and nature and contains both organic and inorganic ions.

The role, safety, and efficacy of hyperbaric oxygen therapy in aesthetic practice-An evidence-based review.

Background: Hyperbaric oxygen therapy (HBOT) involves patients breathing 100% oxygen in a pressurized chamber, above 1 atmosphere. Many centers are now promoting the use of HBOT for skin rejuvenation. However, the current indications for HBOT do not encompass aesthetic applications.

COSMO-RS solute partition ratios for solvent mixtures of unknown composition: Henry's law constants as descriptors for mixture sigma profiles.

Henry's law constants (H) for selected probe molecules have been used as descriptors to estimate the COSMO-RS sigma profiles of solvents and solvent mixtures. Henry's law constants were calculated with COSMOtherm for small sets of probe molecules in 155 organic solvents (training set), and these constants subsequently used as descriptors to model the solvent sigma profiles with 61 multiple linear regression (MLR) equations. Subsequent input into COSMOtherm of weighted basis molecule solvent mixtures whose sigma profiles closely matched those modelled for the training set solvents allowed estimation of air-solvent and water-solvent partition ratios for solutes in solvents and solvent mixtures without input of the solvent or solvent mixture identity.

Comparative study of surgical wound closure with nylon interrupted sutures and running subcuticular vicryl rapide suture after open release of the carpal tunnel.

Background: Surgical decompression of the carpal tunnel is considered the method of choice for its treatment with satisfactory results documented. Various methods and suturing materials have been used for closure of the surgical wound. In the present study, we compared interrupted mattress closure by means of nylon suture to running subcuticular closure with vicryl rapide suture.

Medium- and long-chain chlorinated paraffins in air: A review of levels, physicochemical properties, and analytical considerations.

Chlorinated paraffins (CPs) are synthetic chemicals that are produced at high volumes and have a global presence. CPs are generally divided into three groups based on their carbon chain lengths: short-chain CPs (SCCPs, C), medium-chain CPs (MCCPs, C), and long-chain CPs (LCCPs, C). SCCPs have been formally recognized as persistent organic pollutants (POPs) and have been listed under the Stockholm Convention on POPs.

Novel Bayesian Method to Derive Final Adjusted Values of Physicochemical Properties: Application to 74 Compounds.

Accurate values of physicochemical properties are essential for screening semivolatile organic compounds for human and environmental hazard and risk. approaches for estimation are widely used, but the accuracy of these and measured values can be difficult to ascertain. Final adjusted values (FAVs) harmonize literature-reported measurements to ensure consistency and minimize uncertainty.

Guidance on the Application of Polyurethane Foam Disk Passive Air Samplers for Measuring Nonane and Short-Chain Chlorinated Paraffins in Air: Results from a Screening Study in Urban Air.

This study provides guidance on using polyurethane foam-based passive air samplers (PUF-PASs) for atmospheric nonane chlorinated paraffins (C-CPs) and short-chain CPs (SCCPs) and reports SCCP concentrations in air in the Greater Toronto Area (GTA), Canada. We estimated the partition coefficients between PUF and air () and between octanol and air () for C-CP and SCCP congeners using the COSMO-RS method, so that PUF disk uptake profiles for each formula group could be calculated. We then measured SCCP concentrations in PUF disk samples collected from distinct source sectors in urban air across the GTA.

Environmental modelling of hexamethoxymethylmelamine, its transformation products, and precursor compounds: An emerging family of contaminants from tire wear.

Hexamethoxymethylmelamine (HMMM) is a polymer crosslinking agent used commercially to manufacture tires. HMMM is a ubiquitous contaminant in urban surface waters due to its presence in tire-wear particles and its tendency to be transported into receiving waters during rain events through road runoff. It has recently been determined that this chemical readily transforms into numerous other compounds, several of which have also been detected in the aquatic environment.

Indoor Dust/Air Partitioning: Evidence for Kinetic Delay in Equilibration for Low-Volatility SVOCs.

Effective modeling of semivolatile organic chemical (SVOC) partitioning between air and indoor dust is investigated by calculating partition ratios for selected SVOCs between air and n-octanol as well as 8 other oligomers similar in chemical structure to common components of household dust. COSMO-RS solvation theory was used to calculate air-oligomer partition ratios, which were converted to estimates for (octanol-air) and . The results are compared with reported monitored partition ratios with good agreement for the more volatile SVOCs of vapor pressure (VP) exceeding 10 Pa and corresponding calculated log (m g) of <5.

Property Estimation of Per- and Polyfluoroalkyl Substances: A Comparative Assessment of Estimation Methods.

To accurately predict the environmental fate of per- and polyfluoroalkyl substances (PFAS), high-quality physicochemical property data are required. Because such data are often not available from experiments, assessment of the accuracy of existing property estimation models is essential. The quality of predicted physicochemical property data for a set of 25 PFAS was examined using COSMOtherm, EPI Suite, the estimation models accessible through the US Environmental Protection Agency's CompTox Chemicals Dashboard, and Linear Solvation Energy Relationships (LSERs) available through the UFZ-LSER Database.

A perspective on the role of fugacity and activity for evaluating the PBT properties of organic chemicals and providing a multi-media synoptic indicator of environmental contamination.

The hazard and risk from organic chemicals present in the environment are routinely evaluated using P (persistence), B (bioaccumulation) and T (toxicity) criteria. We present a perspective on how models based on the equilibrium criteria of fugacity and chemical activity can contribute to all three evaluations, thus providing a consistent and seamless assessment process. Persistence and its closely related, but fundamentally different property, chemical residence time can be determined from degradation half-lives (typically obtained from monitoring data) and multi-media mass balance models describing chemical fate and transport in real or evaluative environments.

QSPRs for Molecular Diffusion Coefficients in Polymeric Passive Samplers: A Comparison of Simple Molecular and Quantum-mechanical Sigma-moment Descriptors.

Linear quantitative structure-property relationships (QSPRs) for the prediction of diffusion coefficients (log D ) were developed for organic contaminants in two common passive sampler materials, polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE). Literature data was compiled for both PDMS and LDPE resulting in final data sets of 196 and 79 compounds, respectively. Data sets contained compounds with log D values that ranged over about 5 log units and 3 log units for PDMS and LDPE, respectively.

Estimating the Mass of Chemicals Associated with Ocean Plastic Pollution to Inform Mitigation Efforts.

Plastic pollution in the marine environment is well documented. What remains less recognized and understood are the chemicals associated with it. Plastics enter the ocean with unreacted monomers, oligomers, and additives, which can leach over time.

Kinetic Delay in Partitioning and Parallel Particle Pathways: Underappreciated Aspects of Environmental Transport.

We outline the general conditions under which chemicals of high hydrophobicity or, more generally, high partition ratios (HPRs) in water or air, may experience unexpectedly long kinetic delays in approaching equilibrium conditions with organic media. Such a "hydrophobic delay" in the case of K or an "aerophobic" delay in the case of K may be misinterpreted as being caused by a change in partitioning behavior or mechanism, resulting in development of nonlinear regression models describing intermedia partitioning. In fact, the partitioning is fundamentally linear but is distorted by a kinetic delay in partitioning.

Bioconcentration, bioaccumulation, biomagnification and trophic magnification: a modelling perspective.

We present a modelling perspective on quantifying metrics of bio-uptake of organic chemicals in fish. The models can be in concentration, partition ratio, rate constant (CKk) format or fugacity, Z and D value (fZD) format that are shown to be exactly equivalent, each having it merits. For most purposes a simple, parameter-parsimonious one compartment steady-state model containing some 13 parameters is adequate for obtaining an appreciation of the uptake equilibria and kinetics for scientific and regulatory purposes.

Systems biology of the IMIDIA biobank from organ donors and pancreatectomised patients defines a novel transcriptomic signature of islets from individuals with type 2 diabetes.

Aims/hypothesis: Pancreatic islet beta cell failure causes type 2 diabetes in humans. To identify transcriptomic changes in type 2 diabetic islets, the Innovative Medicines Initiative for Diabetes: Improving beta-cell function and identification of diagnostic biomarkers for treatment monitoring in Diabetes (IMIDIA) consortium ( www.imidia.

Direct and indirect effects of different types of microplastics on freshwater prey (Corbicula fluminea) and their predator (Acipenser transmontanus).

We examined whether environmentally relevant concentrations of different types of microplastics, with or without PCBs, directly affect freshwater prey and indirectly affect their predators. Asian clams (Corbicula fluminea) were exposed to environmentally relevant concentrations of polyethylene terephthalate (PET), polyethylene, polyvinylchloride (PVC) or polystyrene with and without polychlorinated biphenyls (PCBs) for 28 days. Their predators, white sturgeon (Acipenser transmontanus), were exposed to clams from each treatment for 28 days.

The chemical exposure toxicity space (CETS) model: Displaying exposure time, aqueous and organic concentration, activity, and onset of toxicity.

A 1-compartment toxicokinetic model is used to characterize the chemical exposure toxicity space (CETS), providing a novel graphic tool that can aid in the design of aquatic toxicity tests for fish and for interpreting their results. The graph depicts the solution to the differential equation describing the uptake kinetics of a chemical by a modeled fish under conventional bioassay conditions. The model relates the exposure concentration in the water to a dimensionless time and the onset of toxicity as determined by an estimated or assumed critical body residue or incipient lethal aqueous concentration.

Approaches for estimating PUF-air partitions coefficient for semi-volatile organic compounds: A critical comparison.

Partition coefficients between polyurethane foam (PUF) and air (K) are important when using PUF as a passive air sampler for semi-volatile organic compounds (SVOCs) and when considering the fate of SVOCs indoors where PUF is a common material. Here, K for selected SVOCs was estimated using published methods, since measured data are unavailable for most of these compounds. Estimates of K were within one order of magnitude for SVOCs having values of log octanol-air partition coefficient (K) of 5, but differed by nearly three orders of magnitude for SVOCs with log K of 12.

Characterization of polyurethane foam (PUF) and sorbent impregnated PUF (SIP) disk passive air samplers for measuring organophosphate flame retardants.

This study aimed to characterize the uptake of organophosphate esters (OPEs) by polyurethane foam (PUF) and sorbent-impregnated polyurethane foam (SIP) disk passive air samplers (PAS). Atmospheric OPE concentrations were monitored with high-volume active air samplers (HV-AAS) that were co-deployed with passive air samplers. Samples were analyzed for tris(2-chloroisopropyl) phosphate (TCIPP), tri(phenyl) phosphate (TPhP), tris(2-chloroethyl) phosphate (TCEP), and tris(2,3-dichloropropyl) phosphate (TDCIPP).

Oligomeric models for estimation of polydimethylsiloxane-water partition ratios with COSMO-RS theory: impact of the combinatorial term on absolute error.

A series of 12 oligomeric models for polydimethylsiloxane (PDMS) were evaluated for their effectiveness in estimating the PDMS-water partition ratio, K. Models ranging in size and complexity from the -Si(CH)-O- model previously published by Goss in 2011 to octadeca-methyloctasiloxane (CH-(Si(CH)-O-)CH) were assessed based on their RMS error with 253 experimental measurements of log K from six published works. The lowest RMS error for log K (0.