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Introduction: Despite improvement in the computational capabilities of visual displays in flight simulators, intersensory visual-vestibular conflict remains the leading cause of simulator sickness (SS). By using galvanic vestibular stimulation (GVS), the vestibular system can be synchronized with a moving visual field in order to lessen the mismatch of sensory inputs thought to result in SS., Methods: A multisite electrode array was used to deliver combinations of GVS in 21 normal subjects. Optimal electrode combinations were identified and used to establish GVS dose-response predictions for the perception of roll, pitch, and yaw. Based on these data, an algorithm was then implemented in flight simulator hardware in order to synchronize visual and GVS-induced vestibular sensations (oculo-vestibular-recoupled or OVR simulation). Subjects were then randomly exposed to flight simulation either with or without OVR simulation. A self-report SS checklist was administered to all subjects after each session. An overall SS score was calculated for each category of symptoms for both groups., Results: The analysis of GVS stimulation data yielded six unique combinations of electrode positions inducing motion perceptions in the three rotational axes. This provided the algorithm used for OVR simulation. The overall SS scores for gastrointestinal, central, and peripheral categories were 17%, 22.4%, and 20% for the Control group and 6.3%, 20%, and 8% for the OVR group, respectively., Conclusions: When virtual head signals produced by GVS are synchronized to the speed and direction of a moving visual field, manifestations of induced SS in a cockpit flight simulator are significantly reduced.

Reaction of [PtCl(2)(COD)] and [PtI(2)(COD)] with 2,7-di-tert-butyl-5-diphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene (TXPB) afforded square planar [PtCl(2)(TXPB)] (1B) and [PtI(2)(TXPB)] (4B), both of which were crystallographically characterized. Single-crystal X-ray quality crystals were also obtained for [PdCl(2)(TXPB)] (2B; Emslie et al., Organometallics, 2008, 27, 5317) as 2B·2CH(2)Cl(2) and solvent-free 2B. Both the chloro and iodo TXPB complexes exhibit metal-halide-borane bridging interactions similar to those in previously reported [RhCl(CO)(TXPB)] (3B) and [RhI(CO)(TXPB)] (5B) (Emslie et al., Organometallics, 2006, 25, 583 and Inorg. Chem., 2010, 49, 4060). To facilitate a more detailed analysis of M-X-BR(3) (X = Cl and I) interactions, a borane-free analogue of the TXPB ligand, 2,7-di-tert-butyl-4-diphenylphosphino-9,9-dimethylthioxanthene (TXPH), was prepared. Reaction with [PtX(2)(COD)] (X = Cl or I), [PdCl(2)(COD)] and 0.5 [{RhCl(CO)(2)}(2)] provided square planar [PtCl(2)(TXPH)] (1H), [PdCl(2)(TXPH)] (2H), [RhCl(CO)(TXPH)] (3H) and [PtI(2)(TXPH)] (4H). M-Cl-BR(3) and M-I-BR(3) bonding in 1B-5B was then probed through the use of structural comparisons, IR and NMR spectroscopy, cyclic voltammetry, and DFT calculations (Slater-type orbitals, Mayer bond orders, Hirshfeld charges, fragment analysis, SCF deformation density isosurfaces, and energy decomposition analysis).

Galvanic stimulation has long been used as a nonmechanical means of activating the vestibular apparatus through direct action on the vestibular nerve endings. This stimulation has been reported to be safe, but no studies have examined the potential changes in the corresponding cochlear receptors. The aim of the present study was to evaluate the effect of galvanic vestibular stimulation (GVS) on distortion product otoacoustic emissions (DPOAEs). Fourteen subjects underwent DPOAEs during several conditions of GVS. The DPOAEs ranged from ∼ 1 kHz to ∼ 8 kHz at 65/55 dB for f1/f2 and with an f2/f1 ratio of 1.2. The subjects were evaluated at 10 stimulation conditions that ranged from -2.0 mA to +2.0 mA for each frequency. Statistical analysis showed no significant differences in DPOAE amplitudes for all conditions with and without GVS. Results also showed no significant differences between DPOAE amplitudes before and after GVS. Multivariate analysis found subject variability in DPOAE amplitude, which was not thought to be GVS related. Results indicated that GVS produced neither temporary nor permanent changes in DPOAEs.

Reactions of indigo with a variety of substituted anilines produce the corresponding indigo diimines ("Nindigos") in good yields. Nindigo coordination complexes are subsequently prepared by reactions of the Nindigo ligands with Pd(hfac)(2). In most cases, binuclear complexes are obtained in which the deprotonated Nindigo bridges two Pd(hfac) moieties in the expected bis-bidentate binding mode. When the Nindigo possesses bulky substituents on the imine (mesityl, 2,6-dimethylphenyl, 2,6-diisopropylphenyl, etc.), mononuclear Pf(hfac) complexes are obtained in which the Nindigo core has isomerized from a trans- to a cis-alkene; in these structures, the palladium is bound to the cis-Nindigo ligand at the two indole nitrogen atoms; the remaining proton is bound between the imine nitrogen atoms. The palladium complexes possess intense electronic absorption bands [near 920 nm for the binuclear complexes and 820 nm for the mononuclear cis-Nindigo complexes; extinction coefficients are (1.0-2.0) × 10(4) M(-1) cm(-1)] that are ligand-centered (π-π*) transitions. Cyclic voltammetry investigations reveal multiple redox events that are also ligand-centered in origin. All of the palladium complexes can be reversibly oxidized in two sequential one-electron steps; the binuclear complexes are reduced in a two-electron process whose reversibility depends on the Nindigo ligand substituent; the mononuclear palladium species show two one-electron reductions, only the first of which is quasi-reversible.

Background: A few studies in the literature have reported postural changes with hypoxia, but none have quantified the magnitude of change. Further understanding of this condition could have implications for patients at risk for falls, individuals undergoing acute altitude exposure, and pilots and commercial passengers. The objective of this study was to evaluate the effect of different levels of hypoxia (oxygen nitrogen mixtures) on postural standing balance using the computerized dynamic posturography (CDP) system. This improves upon previous protocols by manipulating vision and standing balance with a sway-referenced visual field and/or platform. Additionally, normative data were available for comparison with the cumulative test scores and scores for each condition., Methods: Altitude hypoxia was simulated by use of admixing nitrogen to the breathing gas to achieve equivalent altitudes of 1524 m, 2438 m, and 3048 m. Subjects were evaluated using the CDP system., Results: Subjects showed an overall trend toward decreased performance at higher simulated altitudes consistent with the initial hypothesis. Composite standing balance sway scores for the sensory organization subtest of CDP were decreased compared to baseline for simulated altitudes as low as 2438 m (mean sway scores: 81.92 at baseline; 81.85 at 1524 m; 79.15 at 2438 m; 79.15 at 3048 m). Reaction times to unexpected movements in the support surface for the motor control subtest (MCT) increased compared to baseline (mean composite scores: 133.3 at baseline; 135.9 ms at 1524 m; 138.0 ms at 2438 m; 140.9 ms at 3048 m)., Conclusions: The CDP testing provided a reliable objective measurement of degradation of balance under hypoxic conditions.

This case study details the evaluation, explantation, and subsequent reimplantation of a cochlear implant (CI) recipient with an unusually deep electrode array insertion. Although the positive value of sufficiently deep insertion and the effect of insertion variability have been researched, there are few data available that illustrate the detrimental effects on speech recognition when deep insertion corrupts optimal use of the CI. This unique case report challenges the assumption that deeper insertion will result in improved speech understanding and demonstrates the importance of fully evaluating recipients' complaints and recognizing the impact of frequency-to-place mismatch.

Reactions of indigo with anilines provide a simple route to indigo N,N'-diaryldiimines ("Nindigo"), a new binucleating ligand with two beta-diketiminate-type metal binding sites. Bis-palladium complexes have interesting ligand-centred properties such as redox activity and intense near infrared absorption.