Randomized Trial of 2 Self-Titrated Oral Appliances for Airway Management

The effectiveness and predictability of 2 different oral appliance (OA) designs to reduce the respiratory event index (REI) in moderate and severe obstructive sleep apnea (OSA) patients requires elucidation. The primary aim of the trial was to determine if 2 widely used midline-traction and bilateral-thrust OA designs differ in effectiveness to reduce the REI within a single test population categorized by OSA severity. Moderate and severe adult OSA patients, who were previously prescribed continuous positive airway pressure therapy (CPAP) but were dissatisfied with it (n = 56), were studied by home-polygraphy in a randomized crossover trial using either midline-traction with restricted mouth opening (MR) or bilateral thrust with opening permitted (BP) design OAs. OAs were used nightly for 4 wk (T2) followed by a 1-wk washout period, then 4 wk (T4) using the alternate OA. REI and oxygen saturation (SaO₂) were primary outcomes, while predictability and efficacy comparison of the 2 OAs were secondary outcomes. Thirty-six participants had used MR and BP OAs during both 4-wk study legs. Twenty (55.6%) MR OA-using participants, 25 (69.4%) BP OA-using participants, and 16 (44.4%) participants using both OAs had significant REI reductions. Overall baseline (T0) median REI (interquartile range) of 33.7 (20.7-54.9) was reduced to 18.0 (8.5-19.4) at T2 and to 12.5 (8.2-15.9) at T4 (P < 0.001). Comparison of the 2 sequence groups' (MR-BP and BP-MR) REI showed the median differences between T0 and T2 and T4 were highly significant (P < 0.001). Regression analysis predicted about half of all users will have REIs between 8 and 16 after 2 mo. Baseline overjet measures >2.9 mm predicted greater OA advancement at T4. Mean and minimum SaO₂ did not change significantly from T0 to T2 or T4. MR and BP OA designs similarly attenuated REI in moderate and severe OSA individuals who completed the 8-wk study protocol with greater REI reduction in those with severe OSA (ClinicalTrials.gov NCT03219034).

Rapid determination of surfactant critical micelle concentrations using pressure-driven flow with capillary electrophoresis instrumentation

This work demonstrates a novel, convenient utilization of capillary electrophoresis (CE) instrumentation for the determination of critical micelle concentrations (CMCs). Solution viscosity differences across a range of surfactant concentrations were monitored by hydrodynamically forcing an analyte towards the detector. Upon reaching the surfactant's CMC value, migration times were observed to change drastically. CMC values for four commonly employed anionic surfactants were determined-sodium dodecyl sulfate: 8.1mM; sodium caprylate: 300 mM; sodium decanoate: 86 mM; sodium laurate: 30 mM; and found to be in excellent agreement with values previously reported in the literature. The technique was then applied to the less well-characterized nonionic surfactants poly(oxyethylene) 8 myristyl ether (CMC approximately 9 M), poly(oxyethylene) 8 decyl ether (CMC approximately 0.95 mM) and poly(oxyethylene) 4 lauryl ether.

Use of dyes to investigate migration of the chiral selector in CFFE and the impact on the chiral separations

Continuous free flow electrophoresis was investigated as a tool for the preparative chiral separation of piperoxan enantiomers using sulfated beta-cyclodextrin (sbeta-CD) as the chiral additive. Bulk migration of sbeta-CD was confirmed using LC-MS analysis of the individual fractions collected and visualized with the addition of crystal violet to the separation buffer. In the absence of sbeta-CD, the crystal violet-containing buffer was reddish/purple and the crystal violet was deflected cathodically in the chamber. In the presence of sbeta-CD, the crystal violet-containing buffer was blue and was deflected anodically. However, formation of accumulation and depletion zones was apparent in both cases. The addition of sbeta-CD to the cathodic wash solution allowed for almost complete resolution of the piperoxan enantiomers with a processing rate of 0.45 mg/ h.

Cyclodextrins: a versatile tool in separation science

Cyclodextrins have been used extensively in separation science because they have been shown to discriminate between positional isomers, functional groups, homologues and enantiomers. This property makes them one of the most useful agents for a wide variety of separations. The main goal of this review is a discussion of somewhat more exotic applications of cyclodextrins to separation methods. Techniques examined in detail include gel electrophoresis, isotachophoresis, isoelectric focusing, preparative scale electrophoretic techniques, thin-layer chromatography, electrochemically modulated liquid chromatography, use of monolithic media in liquid chromatography, microdialysis, separation on hollow fibers, foam flotation enrichment, solid- and liquid-phase extractions, countercurrent chromatography, separation through liquid and composite membranes, and cyclodextrin applications in molecularly imprinted polymers. Since a lot of attention has been paid to use of cyclodextrins in capillary electrophoresis, liquid, gas and supercritical fluid chromatography, these techniques will be only briefly discussed. The second goal of this review is a discussion of a scaling-up the analytical separations to semi-preparative or preparative techniques. It was found that despite a need for large scale separations in the industry, development of these techniques has been somewhat lagging behind development of miniaturized analytical separations. It is hoped that the focus on areas outside more traditional separation applications might stimulate further research.

Condylar movement and centric relation in patients with internal derangement of the temporomandibular joint

This study was designed to compare the reproducibility of the condylar translation pathway and the centric relation position in patients with and without internal derangement of the temporomandibular joint. Reproducibility of condylar movement and variability of the axis point of condylar rotation in centric relation was studied in 15 patients with internal derangement of the temporomandibular joint and 15 patients with no history or clinical signs of mandibular dysfunction. Condylar movement and axis point location were recorded with a sagittal recording device at three separate recording sessions. Lead markers were placed on the skin over the axis and orbital points, and lateral cephalometric radiographs were taken at each session. Analysis of cephalometric and axiographic recordings included both linear and angular measurements. Analysis of the condylar movement pathway revealed greater within-subject reproducibility in the control group for both the right and left condyles (p < 0.0005 and p < 0.0003, respectively). The axis point of condylar rotation in centric relation, as shown by cephalometric analysis, had significantly more within-subject variability in the horizontal plane for the control group (p < 0.003). There was no significant difference between groups for within-subject variability of condylar position in the vertical direction. These findings are consistent with the contemporary concept of centric relation that a vertically stable condyle with a disk interposed against the anterior eminence is capable of functional adaptation in the horizontal plane. The results have implications with regard to treatment and rehabilitation of patients with temporomandibular joint internal derangement.

The effectiveness of an interactive instructional context. Principles from the parent-child interaction literature

In the present study, the effectiveness of embedding a targeted linguistic structure within an interactive instructional context is examined. Ten subjects participated in a communication-games intervention which contained seven interactive elements drawn from the parent-child interaction literature. Ten subjects were assigned to a control group. A comparison of student performance before and after intervention supports the effectiveness of adopting instructional strategies that are consistent with a social-interaction perspective on language development. Qualitative results are presented that illustrate each of the interactional characteristics of the intervention. Implications for practice are discussed.