A variety of sorbents is available for the sampling of airborne organic pollutants. However, choosing the right sorbent for a certain analytical target is still a challenge. Here we present a systematic sorption study for a diverse set of up to 200 compounds at temperatures between 40 and 250 degrees C for four frequently used sorbents: Tenax TA, Chromosorb 106, Porapak N, and Carbopack F.
View Article and Find Full Text PDFIn a companion paper we reported that, for apolar and most polar compounds, the dominating sorption mechanism governing ambient gas/particle partitioning under dry conditions is absorption into a water-insoluble organic matter (WIOM) phase, whereas under moist conditions, polar and ionized compounds can partition additionally into a mixed-aqueous phase. In order to understand how sorption into the WIOM varies for particles from diverse terrestrial locations, we looked at over 500 equilibrium gas/particle partitioning constants, Kip, measured at a specific temperature and relative humidity (15 degrees C, 50% RH), covering aerosol samples from all seasons and various locations. The data indicate that for every sample the WIOM exhibits similar intermolecular interactions with gas-phase organic compounds.
View Article and Find Full Text PDFThere remain several ambiguities in the literature regarding the dominating sorption mechanisms involved in gas/particle partitioning, particularly for polar and ionizable compounds. The various hypothetical mechanisms would depend differently on relative humidity (RH) and the presence of various aerosol components. Thus, in order to resolve these ambiguities, here we measured the RH-dependency of gas/particle partitioning constants, K(ip), for four diverse aerosol samples and a large set of chemicals covering apolar, polar, and ionizable organic compounds.
View Article and Find Full Text PDFPredicting the partition behavior of bifunctional molecules from their molecular structure is a challenge because the combination of two or more functional groups often has nonadditive effects. Data presented here and in the literature reveal that isomers of bifunctional compounds can exhibit partition constants that differ by several orders of magnitude. These effects are not limited to compounds with intramolecular H-bonds.
View Article and Find Full Text PDFHuman conducting airways contain two anatomically distinct epithelial cell compartments: surface epithelium and submucosal glands (SMG). Surface epithelial cells interface directly with the environment and function in pathogen detection, fluid and electrolyte transport, and mucus elevation. SMG secrete antimicrobial molecules and most of the airway surface fluid.
View Article and Find Full Text PDFEquilibrium partitioning coefficients between an industrial coal tar sample and water (KCT/w) were determined for 41 polar and nonpolar solutes in batch systems. Together with literature values, 69 KCT/w data were analyzed using the following model approaches: Raoult's law, the single parameter linear free energy relationship (SPLFER) with octanol-water partitioning coefficients (Kow), the linear solvation energy relationships (LSERs), SPARC and COSMOtherm. Estimations by Raoult's law and the SPLFER agreed well with the experimental log KCT/w values for the investigated coal tar, with root mean square errors (RMSE) of 0.
View Article and Find Full Text PDFClin Podiatr Med Surg
July 2008
Regional anesthesia with local anesthetics is an important component of the perioperative pain management algorithm in the context of lower extremity orthopedic surgery. These techniques have proved to be consistent and effective in minimizing postoperative pain and narcotic usage, and in reducing the morbidity associated with lower extremity surgery. The mechanisms of local anesthetic agents as they relate to acute surgical pain are reviewed in this article, with an emphasis on the low sciatic nerve block.
View Article and Find Full Text PDFLinear solvation energy relationships (LSERs) have more recently been proposed as the method of choice to describe and/or predict the partitioning behavior of neutral organic compounds over a large range of environmental matrices and for a broad variety of compounds in a consistent manner. However, when dealing with more complex, polar compounds with multiple functional groups, it has also been noted that there is a severe lack of substance descriptors quantifying the different intermolecular interactions that these compounds may undergo. In this study, we used a system of eight reversed phase, normal phase, and hydrophilic interaction HPLC systems to determine the substance descriptors for H-bond donor (A) and acceptor (B) interactions and for polarizability and dipolarity (S) for a set of 76 complex compounds containing multiple functional groups, comprising mainly pesticides and some pharmaceuticals.
View Article and Find Full Text PDFEnviron Sci Technol
January 2008
The dissociated and nondissociated species of any organic acid differ largely in their physicochemical behavior. The ratio of both species in aqueous systems is determined by the respective pKa value. For perfluorooctanoic acid recent fate-modeling studies have applied a pKa value of 2.
View Article and Find Full Text PDFChlorophenol isomers are known to possess substantially different octanol/water and octane/water partition constants depending on whether the chlorine substituents are in the ortho or meta/para position. Here we show that the same is also true for environmental partition processes such as water/air and humic acid/air partitioning. Quantitative structure property relationships (QSPR) such as those in the widely used EPI-suite or SPARC fail to correctly predict this influence of the substituent position on the compound's partitioning.
View Article and Find Full Text PDFBackground: Surfactant protein D (SP-D) is an innate immune protein that is present in mucosal lined surfaces throughout the human body, including the male reproductive tract. In the present study, we characterized the regulation of SP-D expression in the mouse and rat prostate.
Methods: Real time reverse transcriptase polymerase chain reaction (RT-PCR) and immunostaining were used to characterize SP-D mRNA and protein in the mouse male reproductive tract.
In this work we present a dataset of more than 1000 natural organic matter (NOM)/air partition coefficients covering polar and nonpolar organic compounds measured in 10 different humic and fulvic acids (HAs/FAs) from terrestrial and aquatic origins. Differences of more than 1 order of magnitude in the sorption coefficients of a given compound measured in HAs and FAs from different origins were found. The terrestrial HAs exhibited substantially higher sorption coefficients compared to aquatic HAs and FAs.
View Article and Find Full Text PDFThe collectins surfactant-associated protein A (SP-A) and SP-D are components of innate immunity that are present before birth. Both proteins bind pathogens and assist in clearing infection. The significance of SP-A and SP-D as components of the neonatal immune system has not been investigated.
View Article and Find Full Text PDFSurfactant protein D (SP-D) plays a role in innate immunity in the lung and is expressed at many other mucosal surfaces throughout the human body. In this study, we show that SP-D mRNA and protein are present in the murine female reproductive tract; i.e.
View Article and Find Full Text PDFEnviron Sci Technol
May 2007
Classical approaches for predicting soil organic matter partition coefficients of organic compounds require a calibration with experimental partition data and, for good accuracy, experimental compound descriptors. In this study we evaluate the quantum chemical model COSMO-RS in its COSMOtherm implementation for the prediction of about 200 experimental Leonardite humic acid/air partition coefficients without calibration or experimental compound descriptors, but simply based on molecular structures. For this purpose a Leonardite Humic Acid model monomer limited to 31 carbon atoms was derived from 13C NMR analysis, elemental analysis, and acidic function analysis provided in the literature.
View Article and Find Full Text PDFPolyurethane foams (PUFs) have long been used for the sampling of airborne organic pollutants. However, a comprehensive investigation of their sorption properties for various organic compounds is still lacking. Here we present a systematic sorption study for a diverse set of up to 100 compounds at temperatures between 15 and 95 degrees C, at various humidities, and for various types of PUFs.
View Article and Find Full Text PDFEnviron Sci Technol
December 2006
Due to their high degree of fluorination, highly fluorinated compounds (HFCs) have unique substance properties that differ from many other organic contaminants. To predict the environmental behavior of HFCs, models that predict both absorptive and adsorptive partitioning are needed; however, the accuracy of existing models has not heretofore been thoroughly investigated for these compounds. This report has two parts: first we show that a well-established polyparameter linear free energy relationship used to predict experimental adsorption constants underestimates values for HFCs by several orders of magnitude.
View Article and Find Full Text PDFIn a recent publication we presented experimental Leonardite humic acid/air partition coefficients for 188 polar and nonpolar organic compounds measured with one consistent method. In this paper these experimental data are evaluated with various model predictions. For the PcKocWIN model some major shortcomings become apparent.
View Article and Find Full Text PDFThe environmental fate of volatile and semivolatile organic compounds is determined by their partitioning between air and soil constituents, in particular soil organic matter (SOM). While there are many studies on the partitioning of nonpolar compounds between water and SOM, data on sorption of polar compounds and data for sorption from the gas phase are rather limited. In this study, Leonardite humic acid/air partition coefficients for 188 polar and nonpolar organic compounds at temperatures between 5 and 75 degrees C and relative humidities between < 0.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
December 2006
In mice, alveolarization occurs during postnatal days 4 through 12, when secondary alveolar septae create thin-walled alveoli in the distal lung. We hypothesized that genes predominantly expressed in newly forming secondary alveolar septae influence the process of alveolarization. To address this hypothesis, tips of secondary alveolar septae were isolated from sections of postnatal day 6 mouse lung tissue using laser capture microdissection.
View Article and Find Full Text PDFJ Phys Chem A
August 2006
Highly fluorinated organic compounds are often said to exhibit unique sorption and partition properties. Terms such as "fluorophilicity" have been used to describe these properties, and fudge factors depending on the degree of fluorination have been used in predictive partition models to make them work for fluorinated solutes. Here we demonstrate that highly fluorinated compounds differ from other molecules only in that they exhibit van der Waals interactions much smaller than those of other molecules of same size.
View Article and Find Full Text PDFIn this paper we present a number of equilibrium partition constants for fluorotelomer alcohols and olefins among them data for air/water and octanol/air partitioning. These data are typically required for environmental fate modeling. Our data deviate substantially from those in the literature.
View Article and Find Full Text PDFRenal tubular epithelial cells synthesize laminin (LN)5 during regeneration of the epithelium after ischemic injury. LN5 is a truncated laminin isoform of particular importance in the epidermis, but it is also constitutively expressed in a number of other epithelia. To investigate the role of LN5 in morphogenesis of a simple renal epithelium, we examined the synthesis and function of LN5 in the spreading, proliferation, wound-edge migration, and apical-basal polarization of Madin-Darby canine kidney (MDCK) cells.
View Article and Find Full Text PDFA model used to predict equilibrium adsorption to surfaces using a poly-parameter linear free-energy relationship as well as an empirical model used to predict enthalpies of adsorption of volatile compounds were evaluated with new experimental data to cover semivolatile compounds and a larger variability of compound classes. Equilibrium adsorption constants on a quartz surface ranging over seven orders of magnitude were measured for 142 compounds, and enthalpies of adsorption on a quartz surface from -33.7 to -99.
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