Role of Body Dysmorphic Disorder in Patients With Postparalytic Facial Synkinesis.

OBJECTIVES/HYPOTHESIS: To evaluate the role of body dysmorphic disorder (BDD) in patients with postparalytic facial nerve syndrome with synkinesis (PFS). STUDY DESIGN: A single-center retrospective cohort study. METHODS: A total of 221 adults (74% women; median age: 44 years; median duration since onset of facial palsy: 1.6 years) were included. To diagnose BDD, the BDD Munich Module was used. Associations with House-Brackmann grading, Stennert index grading, Facial Clinimetric Evaluation (FaCE) survey, Facial Disability Index (FDI), general quality of life (SF-36), Beck Depression Inventory (BDI), and the Liebowitz Social Anxiety Scale (LSAS) was analyzed. RESULTS: A total of 59 patients (27%) were classified as patients with BDD. Significant associations were found between the diagnosis of BDD and female gender and lower FDI, FaCE, and SF-36 scores and higher BDI and LSAS scores. Multivariate analysis revealed BDI, FaCE total score, and FaCE social function subscore as independent factors associated with BDD. CONCLUSION: BDD was a relevant diagnosis in patients with PFS. A higher BDD level was associated with general and facial-specific quality of life and more psychosocial disabilities. Optimal treatment of PFS has to include these nonmotor dysfunctions. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2518-E2524, 2021.

Solvent Transfer-Efficiency of Risk Management Measures.

A series of laboratory simulations were conducted in order to determine the airborne protection that might be afforded by different combinations of workplace exposure controls typically encountered when handling volatile solvents (e.g. solvent transfer). These conditions, referred to as risk management measures (RMMs) under the Registration, Evaluation and Authorisation of Chemicals Regulation (REACH), are typically described using standard phrases in safety data sheets [and specifically those of the European Phrase Catalogue (EUPhraC)]. Ethanol was used as a model compound and its emissions were monitored continuously with a portable IR spectrometer at 3000 cm-1. The average emission reduction performance of the investigated RMMs (e.g. containment, extract ventilation, drum pump) exceeded 90%. They present suitable ways to reduce airborne solvent exposure in a workplace and confirmed the initial expectations derived at by the European Solvents Industry Group (ESIG) and the European Centre For Ecotoxicology and toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) model.

Validation of Lower Tier Exposure Tools Used for REACH: Comparison of Tools Estimates With Available Exposure Measurements.

BACKGROUND: Tier 1 exposure tools recommended for use under REACH are designed to easily identify situations that may pose a risk to health through conservative exposure predictions. However, no comprehensive evaluation of the performance of the lower tier tools has previously been carried out. The ETEAM project aimed to evaluate several lower tier exposure tools (ECETOC TRA, MEASE, and EMKG-EXPO-TOOL) as well as one higher tier tool (STOFFENMANAGER®). This paper describes the results of the external validation of tool estimates using measurement data. METHODS: Measurement data were collected from a range of providers, both in Europe and United States, together with contextual information. Individual measurement and aggregated measurement data were obtained. The contextual information was coded into the tools to obtain exposure estimates. Results were expressed as percentage of measurements exceeding the tool estimates and presented by exposure category (non-volatile liquid, volatile liquid, metal abrasion, metal processing, and powder handling). We also explored tool performance for different process activities as well as different scenario conditions and exposure levels. RESULTS: In total, results from nearly 4000 measurements were obtained, with the majority for the use of volatile liquids and powder handling. The comparisons of measurement results with tool estimates suggest that the tools are generally conservative. However, the tools were more conservative when estimating exposure from powder handling compared to volatile liquids and other exposure categories. In addition, results suggested that tool performance varies between process activities and scenario conditions. For example, tools were less conservative when estimating exposure during activities involving tabletting, compression, extrusion, pelletisation, granulation (common process activity PROC14) and transfer of substance or mixture (charging and discharging) at non-dedicated facilities (PROC8a; powder handling only). With the exception of STOFFENMANAGER® (for estimating exposure during powder handling), the tools were less conservative for scenarios with lower estimated exposure levels. CONCLUSIONS: This is the most comprehensive evaluation of the performance of REACH exposure tools carried out to date. The results show that, although generally conservative, the tools may not always achieve the performance specified in the REACH guidance, i.e. using the 75th or 90th percentile of the exposure distribution for the risk characterisation. Ongoing development, adjustment, and recalibration of the tools with new measurement data are essential to ensure adequate characterisation and control of worker exposure to hazardous substances.

Between-User Reliability of Tier 1 Exposure Assessment Tools Used Under REACH.

When applying simple screening (Tier 1) tools to estimate exposure to chemicals in a given exposure situation under the Registration, Evaluation, Authorisation and restriction of CHemicals Regulation 2006 (REACH), users must select from several possible input parameters. Previous studies have suggested that results from exposure assessments using expert judgement and from the use of modelling tools can vary considerably between assessors. This study aimed to investigate the between-user reliability of Tier 1 tools. A remote-completion exercise and in person workshop were used to identify and evaluate tool parameters and factors such as user demographics that may be potentially associated with between-user variability. Participants (N = 146) generated dermal and inhalation exposure estimates (N = 4066) from specified workplace descriptions ('exposure situations') and Tier 1 tool combinations (N = 20). Interactions between users, tools, and situations were investigated and described. Systematic variation associated with individual users was minor compared with random between-user variation. Although variation was observed between choices made for the majority of input parameters, differing choices of Process Category ('PROC') code/activity descriptor and dustiness level impacted most on the resultant exposure estimates. Exposure estimates ranging over several orders of magnitude were generated for the same exposure situation by different tool users. Such unpredictable between-user variation will reduce consistency within REACH processes and could result in under-estimation or overestimation of exposure, risking worker ill-health or the implementation of unnecessary risk controls, respectively. Implementation of additional support and quality control systems for all tool users is needed to reduce between-assessor variation and so ensure both the protection of worker health and avoidance of unnecessary business risk management expenditure.

Solute-solvent interactions in cryosolutions: a study of halothane-ammonia complexes.

The formation of C-H···N bonded complexes of halothane with ammonia has been studied using infrared and Raman spectroscopy of solutions in the liquid rare gases argon, krypton and xenon, of supersonic jet expansions and of room temperature vapor phase mixtures. For the solutions and for the vapor phase experiments, the formation of complexes with 1:1 and 1:2 stoichiometry was observed. The complexation enthalpy for the 1:1 complex was determined to be -20 (1) kJ mol(-1) in the vapor phase, -17.0 (5) kJ mol(-1) in liquid xenon and -17.3 (6) kJ mol(-1) in liquid krypton. For the 1:2 complex in liquid xenon, the complexation enthalpy was determined to be -31.5 (12) kJ mol(-1). Using the complexation enthalpies for the vapor phase and for the solutions in liquid xenon and krypton, a critical assessment is made of the Monte Carlo Free Energy Perturbation approach to model solvent influences on the thermodynamical properties of the cryosolutions. The influences of temperature and solvent on the complexation shifts of the halothane C-H stretching mode are discussed.

Conformation-changing aggregation in hydroxyacetone: a combined low-temperature FTIR, jet, and crystallographic study.

Aggregation in hydroxyacetone (HA) is studied using low-temperature FTIR, supersonic jet expansion, and X-ray crystallographic (in situ cryocrystallization) techniques. Along with quantum chemical methods (MP2 and DFT), the experiments unravel the conformational preferences of HA upon aggregation to dimers and oligomers. The O-H···O═C intramolecular hydrogen bond present in the gas-phase monomer partially opens upon aggregation in supersonic expansions, giving rise to intermolecular cooperatively enhanced O-H···O-H hydrogen bonds in competition with isolated O-H···O═C hydrogen bonds. On the other hand, low-temperature IR studies on the neat solid and X-ray crystallographic data reveal that HA undergoes profound conformational changes upon crystallization, with the HOCC dihedral angle changing from ~0° in the gas phase to ~180° in the crystalline phase, hence giving rise to a completely new conformation. These conclusions are supported by theoretical calculations performed on the geometry derived from the crystalline phase.

Temperature-dependent intensity anomalies in amino acid esters: weak hydrogen bonds in protected glycine, alanine and valine.

Esters of glycine, alanine and valine are investigated by FTIR and Raman spectroscopy in supersonic jets as gas phase model systems for the neutral peptide N-terminus. The NH-stretching vibrations exhibit very large temperature- and substitution-dependent intensity anomalies which are related to weak, bifurcated intramolecular hydrogen bonds to the carbonyl group. Comparison to theory is only satisfactory at low temperature. Spectral NH aggregation shifts are small or even negligible and the associated IR intensity is remarkably low. In the case of valine, chirality recognition effects are nevertheless detected and rationalized. Comparison to quantum-chemical calculations for dimers shows that dispersion interactions are essential. It also rules out cooperative hydrogen bond topologies and points at deficiencies in standard harmonic treatments with the linear dipole approximation.

On the weakly C-H···π hydrogen bonded complexes of sevoflurane and benzene.

A vibrational assignment of the anaesthetic sevoflurane, (CF(3))(2)CHOCH(2)F, is proposed and its interaction with the aromatic model compound benzene is studied using vibrational spectroscopy of supersonic jet expansions and of cryosolutions in liquid xenon. Ab initio calculations, at the MP2/cc-pVDZ and MP2/aug-cc-pVDZ levels, predict two isomers for the 1 : 1 complex, one in which the near-cis, gauche conformer of sevoflurane is hydrogen bonded through its isopropyl-hydrogen atom, the other in which the same conformer is bonded through a bifurcated hydrogen bond with the fluoromethyl hydrogen atoms. From the experiments it is shown that the two isomers are formed, however with a strong population dominance of the isopropyl-bonded species, both in the jet and liquid phase spectra. The experimental complexation enthalpy in liquid xenon, ΔH(o)(LXe), of this species equals -10.9(2) kJ mol(-1), as derived from the temperature dependent behaviour of the cryosolution spectra. Theoretical complexation enthalpies in liquid xenon were obtained by combining the complete basis set extrapolated complexation energies at the MP2/aug-cc-pVXZ (X = D,T) level with corrections derived from statistical thermodynamics and Monte Carlo Free Energy Perturbation calculations, resulting in a complexation enthalpy of -11.2(3) kJ mol(-1) for the isopropyl-bonded complex, in very good agreement with the experimental value, and of -11.4(4) kJ mol(-1), for the fluoromethyl-bonded complex. The Monte Carlo calculations show that the solvation entropy of the isopropyl-bonded species is considerably higher than that of the fluoromethyl-bonded complex, which assists in explaining its dominance in the liquid phase spectra.

Dimers of cyclic carbonates: chirality recognition in battery solvents and energy storage.

Dimers of ethylene carbonate and propylene carbonate are created in supersonic jet expansions and characterized by FTIR spectroscopy. Fermi resonances are switched on and off by dimerization. There is a unique centrosymmetric dimer of ethylene carbonate in a pronounced case of complementary chirality synchronization, contributing to its energy storage capacity at melting. Two chiral propylene carbonate molecules combine in more intricate ways. If they have the same handedness, one of them is forced into an axial conformation and the binding partner stays in the more stable equatorial structure. If they have opposite handedness, centrosymmetric dimers of either axial or equatorial conformations are formed. This suggests the usefulness of chirality control in elucidating ionic transport mechanisms in battery solvents and asymmetric catalysis in such solvents.

Brightening and locking a weak and floppy N-H chromophore: the case of pyrrolidine.

The N-H stretching signature of the puckering equilibrium between equatorial and axial pyrrolidine is analyzed via FTIR and Raman spectroscopy in supersonic jets as a function of aggregation. Vibrational temperatures along the expansion axis can be extracted from the Raman spectra and allow for a localization of the compression shock waves. While the equatorial conformation is more stable in the ground state monomer, this preference is probably switched in the excited state with one N-H stretching quantum. Furthermore, the dominant dimer involves an axial donor and the trimer and tetramer structures seem to prefer uniform axial conformations. The IR intensity is boosted by up to 3 orders of magnitude upon aggregation, whereas the Raman scattering intensity shows only moderate hydrogen bond effects. B3LYP and MP2 calculations provide a reasonable description of the N-H vibrational dynamics under the influence of self-aggregation. In mixed dimers with pyrrole, pyrrolidine assumes the role of a hydrogen bond acceptor.

The complexes of halothane with benzene: the temperature dependent direction of the complexation shift of the aliphatic C-H stretching.

The formation of C-H...π bonded complexes of halothane with benzene(-d(6)) has been studied using infrared and Raman spectroscopy of solutions in liquid krypton, in supersonic jet expansions and in room temperature vapour phase. The formation of complexes with 1 ∶ 1 and 2 ∶ 1 stoichiometry was observed. The complexation enthalpy in liquid krypton for the 1 ∶ 1 complex was determined to be -9.8(2) kJ mol(-1) and the enthalpy for the addition of a second halothane molecule to the 1 ∶ 1 complex was determined at -7.0(3) kJ mol(-1). The stretching mode of the halothane C-H bond involved in the formation of the complex in the jets was observed to blue shift by 7.7(10) cm(-1). In contrast, for the solutions of liquid krypton and the room temperature measurements a small red shift was observed. Supported by ab initio calculations and Monte Carlo simulations, this shift was explained by the differences in thermal populations of the van der Waals vibrations of the complex in the different experiments.

Quantum-chemical study and FTIR jet spectroscopy of CHCl(3)-NH(3) association in the gas phase.

High level ab initio quantum chemical calculations have been performed on the association of chloroform with ammonia in the gas phase (counterpoise corrected MP2 and coupled-cluster CCSD(T) calculations with 6-311++G(d,p) basis functions). Minimum energy equilibrium structures have been found for CHCl(3)-NH(3) dimer, CHCl(3)-(NH(3))(2) trimer and CHCl(3)-(NH(3))(3) tetramer. Association is characterised by a CHN hydrogen bond between a chloroform and an ammonia molecule, with further ammonia units attached by hydrogen bonds to ammonia and by an electrostatic NHCl interaction to chloroform. Cooperative effects provide additional stabilisation. The complexes exhibit characteristic shifts of vibrational bands and change of IR intensity; in particular there is a pronounced progressive shift of the CH-stretching vibration towards lower wavenumber with each unit of ammonia attached in the complex. The shift is accompanied by an up to 600 fold increase in IR intensity. The experimental FTIR jet spectra have provided firm evidence of CHCl(3)-NH(3) association, with the clearest effects seen in the region of the CH-stretching vibration. First tentative assignments have been made based on the dependence of relative intensities of cluster features on the concentration of monomers, and assignments have been corroborated by the quantum chemical calculations. The present combined ab initio and FTIR spectroscopy study reveals the structure and energetics of cluster formation and intermolecular bonding in CHCl(3)-NH(3) association.

On the low volatility of cyclic esters: an infrared spectroscopy comparison between dimers of gamma-butyrolactone and methyl propionate.

The dramatically lower volatility of gamma-butyrolactone compared to its open chain analog methyl propionate is analyzed at the molecular dimer level using FTIR spectroscopy in supersonic jets. It is found that the spectral shifts from the monomer to the dimer are about three times more pronounced in the lactone at low temperatures. The spectra are consistent with sandwich-like dimers optimizing their strong dipole-dipole interaction, possibly augmented by specific C-H...O=C hydrogen bond contacts. The spectra show significant evolution from the dimer to the condensed phase, indicative of secondary interactions with the ester oxygen and long range forces. The reduced dipole moment in the open chain ester leads to less specific interactions, unless a trans conformation of the ester group as in the lactones is enforced. The latter is not energetically accessible in open chain esters because it would bring the molecular C=O and C-O-C dipole moments into an unfavorable near-parallel orientation, thus their higher volatility.