Correction: Barrier kinetics of adsorption–desorption of alcohol monolayers on water under constant surface tension

Correction for ‘Barrier kinetics of adsorption–desorption of alcohol monolayers on water under constant surface tension’ by Ivan L. Minkov et al., Soft Matter, 2019, DOI: 10.1039/c8sm02076k.

Barrier kinetics of adsorption–desorption of alcohol monolayers on water under constant surface tension

The desorption rate stands between the theoretical curves for pure barrier control (intensive convection) and mixed barrier + diffusion control (no convection).

Water Structure at the Interface of Alcohol Monolayers as Predicted by Computational Vibrational Sum-Frequency Generation Spectroscopy

<div> <div> <div> <p>In this study, we investigate the structure of water at the interface of three long-chain alcohol monolayers differing in alkyl chain length through molecular dynamics simulations combined with modeling of vibrational sum-frequency generation (vSFG) spectra. The effects of alkyl chain parity on interfacial water is examined through extensive analysis of structural properties, hydrogen bonding motifs, and spectral features. Besides providing molecular-level insights into the structure of interfacial water, this study also demonstrates that, by enabling direct comparisons with experimental vSFG spectra, computational spectroscopy may be used to test and validate force fields commonly used in biomolecular simulations. The results presented here can thus serve as benchmarks for both further investigations to characterize ice nucleation induced by alcohol monolayers and refinement of popular biomolecular force fields. </p> </div> </div> </div>

Water Structure at the Interface of Alcohol Monolayers as Predicted by Computational Vibrational Sum-Frequency Generation Spectroscopy

<div> <div> <div> <p>In this study, we investigate the structure of water at the interface of three long-chain alcohol monolayers differing in alkyl chain length through molecular dynamics simulations combined with modeling of vibrational sum-frequency generation (vSFG) spectra. The effects of alkyl chain parity on interfacial water is examined through extensive analysis of structural properties, hydrogen bonding motifs, and spectral features. Besides providing molecular-level insights into the structure of interfacial water, this study also demonstrates that, by enabling direct comparisons with experimental vSFG spectra, computational spectroscopy may be used to test and validate force fields commonly used in biomolecular simulations. The results presented here can thus serve as benchmarks for both further investigations to characterize ice nucleation induced by alcohol monolayers and refinement of popular biomolecular force fields. </p> </div> </div> </div>

Sources of organic ice nucleating particles in soils

Soil organic matter (SOM) may be a significant source of atmospheric ice nucleating particles (INPs), especially of those active > −15 °C. However, due to both a lack of investigations and the complexity of the SOM itself, the identities of these INPs remain unknown. To more comprehensively characterize organic INPs we tested locally representative soils in Wyoming and Colorado for total organic INPs, INPs in the heat-labile fraction, ice nucleating (IN) bacteria, IN fungi, IN fulvic and humic acids, IN plant tissue, and ice nucleation by monolayers of aliphatic alcohols. All soils contained ≈ 106 to ≈ 5 × 107 INPs g−1 dry soil active at −10 °C. Removal of SOM with H2O2 removed ≥ 99 % of INPs active > −18 °C (the limit of testing), while heating of soil suspensions to 105 °C showed that labile INPs increasingly predominated > −12 °C and comprised ≥ 90 % of INPs active > −9 °C. Papain protease, which inactivates IN proteins produced by the fungus Mortierella alpina, common in the region's soils, lowered INPs active at ≥ −11 °C by ≥ 75 % in two arable soils and in sagebrush shrubland soil. By contrast, lysozyme, which digests bacterial cell walls, only reduced INPs active at ≥ −7.5 or ≥ −6 °C, depending on the soil. The known IN bacteria were not detected in any soil, using PCR for the ina gene that codes for the active protein. We directly isolated and photographed two INPs from soil, using repeated cycles of freeze testing and subdivision of droplets of dilute soil suspensions; they were complex and apparently organic entities. Ice nucleation activity was not affected by digestion of Proteinase K-susceptible proteins or the removal of entities composed of fulvic and humic acids, sterols, or aliphatic alcohol monolayers. Organic INPs active colder than −10 to −12 °C were resistant to all investigations other than heat, oxidation with H2O2, and, for some, digestion with papain. They may originate from decomposing plant material, microbial biomass, and/or the humin component of the SOM. In the case of the latter then they are most likely to be a carbohydrate. Reflecting the diversity of the SOM itself, soil INPs have a range of sources which occur with differing relative abundances.

Sources of organic ice nucleating particles in soils

Soil organic matter (SOM) may be a significant source of atmospheric ice nucleating particles (INPs), especially of those active >-15 °C. However, due to both a lack of investigations and the complexity of the SOM itself, the principal sources of these INPs remain unknown. To more comprehensively characterize organic INPs we tested locally representative soils in Wyoming and Colorado for total organic INPs, INPs in the heat-labile fraction, ice nucleating (IN) bacteria, IN fungi, IN fulvic and humic acids, IN plant tissue, and ice nucleation by monolayers of aliphatic alcohols. All soils contained ≈106 to ≈5 ×107 INPs g-1 dry soil active at -10 °C. Removal of SOM with H2O2 effectively removed all INPs active >-18 °C (the limit of testing), while heating of soil suspensions to 105 °C showed that labile INPs increasingly predominated >-12 °C and comprised ≥90% of INPs active >-9 °C. Papain protease, which inactivates IN proteins produced by the fungus Mortierella alpina, common in the region’s soils, lowered INPs active at ≥-11 °C by ≥75% in two arable soil and sagebrush shrubland soil. By contrast, lysozyme, which digests bacterial cell walls, only reduced INPs active at ≥-7.5 or ≥-6 °C, depending on the soil. The known IN bacteria were not detected in any soil, using PCR for the ina gene that codes for the active protein. We directly isolated and photographed two individual INPs from soil, using repeated cycles of freeze-testing and subdivision of droplets of dilute soil sus pensions: They were complex and apparently organic entities. Ice nucleation activity was not affected by digestion of Proteinase K-susceptible proteins or the removal of entities composed of fulvic and humic acids, sterols or aliphatic alcohol monolayers. Organic INPs active at temperatures colder than -10° to -12 °C were resistant to all investigations other than heat, oxidation with H2O2 and, for some, digestion with papain. They may originate from decomposing plant material, microbial biomass and/or the humin component of the SOM. If the latter then they are most likely to be a carbohydrate. Reflecting the diversity of the SOM itself, soil INPs have a range of sources, occur with differing relative abundances, and may be protected by different mechanisms.