Introduction Retinol is known to have positive benefits on the skin including enhancements in barrier function, increased epidermal thickness, reductions in fine lines and wrinkles and reductions in hyperpigmentation. Improved methods to enhance the penetration of retinol are desirable. Methods A study was conducted to examine if addition of natural jojoba ( Simmondsia chinensis ) oil might help passively enhance the penetration of retinol through the skin’s lipid barrier. The model used to examine the passive penetration of the retinol is the skin parallel artificial membrane permeation assay (Skin-PAMPA). In this study, three formulations were examined. The formulations included two control blends: a moisturizing emulsion without retinol and the same product containing 1.0% retinol without jojoba oil. The remaining formulation contained similar concentrations of retinol with 10% jojoba oil. The studies were conducted by applying the products to the Skin-PAMPA models at 37°C/5% CO 2 for 16 hours and then extraction of the acceptor reservoir with cyclohexane (ratio 1:5 acceptor fluid to cyclohexane). The resulting acceptor reservoir cyclohexane solutions were analyzed for retinol by High Performance Liquid Chromatography (HPLC). Results The formulations without retinol showed no indications of retinol penetration by HPLC. The control formulation with 1.0% retinol demonstrated that retinol had permeated the membrane in the 16-hour timeframe with a measured Area Under the Curve (AUC) of 7 units. Analysis of the formulation containing 1.0% retinol and 10% jojoba oil indicated retinol had permeated with a AUC of 285 units, a nearly 40-fold increase in active retinol permeation. Discussion The ability for jojoba oil to directly act to help skin permeation of a key skin care active like retinol has not been previously demonstrated. This potential for jojoba oil to enhance passive skin penetration of critical skin actives, like retinol, can help to improve the performance of skin care products employing active topical ingredients.

Attention-Deficit Hyperactivity Disorder (ADHD) is a common childhood disorder with heterogeneous symptom trajectories. Performance monitoring, which involves the ability to recognize errors and make behavioral adjustments, is one aspect of self-regulation that may contribute to symptom change. Early and late stages of error processing can be quantified via EEG-recorded event-related potentials. The final stage of performance monitoring, which involves making behavioral adjustments, is measured as post-error slowing. It is currently unclear whether impaired performance monitoring is associated with ADHD, specifically, or with comorbid symptoms of Oppositional Defiant Disorder (ODD). Here, better performance monitoring is hypothesized to be associated with ADHD, independent of comorbid ODD symptoms, and to predict ADHD symptom improvement. Method: 122 children from an ongoing longitudinal study (Control= 60, ADHD= 62) completed behavioral ratings and semistructured clinical interviews to assess ADHD and comorbid ODD symptoms. At annual followup visits 5-8 years later, clinical assessment was repeated, and children completed a computerized emotional go/no-go with EEG recorded. Results: Controls had marginally larger ERN (p=.056, η 2 = .03) and larger Pe amplitudes than ADHD participants (F[1,118]=4.38, p=.04). Comorbid ODD did not explain these differences. Adolescents with ADHD also made less adaptive behavioral adjustments in emotional than in non-emotional conditions, F(2,198)=3.758, p=.025. Higher ERN amplitudes during positive conditions predicted greater ADHD symptom improvement, R 2 =.057, p=.016. Conclusions: Performance monitoring is associated with ADHD, independently of ODD. Emotional context does not affect error processing, but may interfere with adaptive behavioral adjustments for individuals with ADHD. Emotion dysregulation may also influence ADHD symptom trajectories.