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Abstract: Saphenous entrapment neuropathy in the distal thigh most commonly occurs at Hunter's canal and is characterized by neurologic symptoms distal to the midthigh in the saphenous nerve distribution. Presented is a 23-year-old active duty female service member with left medial knee pain worse with knee flexion and extension. Evaluation raised suspicion for saphenous nerve entrapment at Hunter's canal, and ultrasound-guided subsartorius fascial plane hydrodissection was performed in addition to focused rehabilitation of the adductor and core musculature. No reports of this treatment have been published to date. This case introduces ultrasound-guided subsartorius fascial plane hydrodissection as novel treatment in Hunter's canal syndrome., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

The surface composition of binary mixtures of the protic ionic liquids ethylammonium nitrate and propylammonium nitrate has been investigated using surface tension measurements and the perfectly surface sensitive method metastable induced electron spectroscopy. Given that the latter technique is sensitive only to the outermost layer, it allows for the determination of the surface fraction occupied by a given species. The piecewise linear relationship between surface fraction and surface tension found in this study can be described by a phase separation within the surface layer.

The charge distribution and coverage with surfactant molecules at foam film surfaces plays an important role in determining foam film structure and stability. This work uses the concentration depth profiling technique neutral impact collision ion scattering spectroscopy to experimentally observe the charge distribution in a foam film for the first time. The charge distribution at the surface of a foam film and the surface of the corresponding bulk liquid were measured for a cationic surfactant solution and the surface excess as well as the electric potential were determined. Describing the internal pressure of foam films by using the electrochemical potential is introduced as a new concept. The foam film can be seen to have a more negative surface charge compared to the bulk liquid surface due to re-arranging of the surfactant molecules. It is discussed how the change in surface excess and electric potential change the electrochemical potential and the stability of the foam film., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Differences in the surface structure of protic ionic liquids (ILs) with three different cations and a common anion; ethyl-, propyl- and 2-hydroxyethyl- (or ethanol-) ammonium nitrate (EAN, PAN and EtAN, respectively) have been observed by neutral impact collision ion scattering spectroscopy (NICISS) and metastable induced electron spectroscopy/ultraviolet photoelectron spectroscopy (MIES/UPS). NICISS is used to determine the concentration depth profiles of the elements in each IL and it reveals an enrichment of cation alkyl chains of PAN and EtAN in the outermost layer compared to EAN, and a corresponding depletion of nitrate from the outermost layer of the EtAN surface. MIES probes the molecular orbitals of only the species in the outermost layer of a sample and confirms that, while both the anion and the cation are present to some degree at the surface of all three ILs, the cation is enriched to a greater extent at the surface of PAN and EtAN compared to EAN.

The nanostructure of the ethanolammonium nitrate (EtAN)-air surface has been investigated using X-ray reflectometry (XRR), vibrational sum frequency spectroscopy (VSFS) and neutral impact collision ion scattering spectroscopy (NICISS). The XRR data decays more rapidly than expected for a perfectly sharp interface, indicating a diffuse electron (scattering length) density profile. Modelling of the XRR data using three different fitting routines produced consistent interfacial profiles that suggest the formation of interfacial EtAN clusters. Consistent with this, VSFS reveals that the EtAN surface is predominantly covered by -CH(2)- moieties, with the -NH(3)(+) and -OH groups of the cation buried slightly deeper in the interface. The elemental profiles determined using NICISS also show enrichment of carbon relative to nitrogen and oxygen in the outermost surface layer, which is consistent with the surface cation orientation deduced from VSFS, and with the presence of EtAN aggregates at the liquid surface., (This journal is © the Owner Societies 2012)

The influence of small amounts of water dissolved in 1-hexyl-3-methylimidazolium chloride ([C(6)mim][Cl]) on the composition of the surface of the ionic liquid is investigated with the depth profiling technique neutral impact collision ion scattering spectroscopy. The concentration depth profiles of the elements in the sample were determined at three different water concentrations and show that small amounts of water affect the charge distribution in the ionic liquid along the surface normal. At low water concentrations (2500 ppm) the cation shows a strong presence at the surface with the alkyl chains oriented towards the gas phase, followed by a layer of anions below the alkyl chains of the cation. At higher water content (6000 to 10,000 ppm) the chloride anion shows an increased concentration at the ionic liquid surface while the alkyl chains move towards the bulk showing that the surface charge becomes more negative with increasing water content. The effect is attributed to the influence of water on the hydrogen bonding network in the ionic liquid.

Neutral impact collision ion scattering spectroscopy (NICISS) was used to determine the surface structure of three ionic liquids, 1-hexyl-3-methylimidazolium [C(6)mim], 1-octyl-3-methylimidazolium [C(8)mim], 1-decyl-3-methylimidazolium [C(10)mim] tetrafluoroborates [BF(4)]. Concentration depth profiles of the elements in an ionic liquid (IL) homologous series with a common anion were obtained. We show that separation between the oppositely charged ions is seen for all three ionic liquids, resulting in an electrical double layer formation. The surface charge shifts from more positive to more negative with increasing aliphatic chain length.

Equipment is developed to measure the concentration depth profiles in foam films with the vacuum based technique neutral impact collision ion scattering spectroscopy. Thin foam films have not previously been investigated using vacuum based techniques, hence specialized methods and equipment have been developed for generating and equilibrating of foam films under vacuum. A specialized film holder has been developed that encloses the foam film in a pressure cell. The pressure cell is air-tight except for apertures that allow for the entrance and exit of the ion beam to facilitate the analysis with the ion scattering technique. The cell is supplied with a reservoir of solvent which evaporates upon evacuating the main chamber. This causes the cell to be maintained at the vapor pressure of the solvent, thus minimizing further evaporation from the films. In order to investigate the effect of varying the pressure over the films, a hydrostatic pressure is applied to the foam films. Concentration depth profiles of the elements in a thin foam film made from a solution of glycerol and the cationic surfactant hexadecyltrimethylammonium bromide (C(16)TAB) were measured. The measured concentration depth profiles are used to compare the charge distribution in foam films with the charge distribution at the surface of a bulk solution. A greater charge separation was observed at the films' surface compared to the bulk surface, which implies a greater electrostatic force contribution to the stabilization of thin foam films.