Multiple-wavelength focusing of surface plasmons with a nonperiodic nanoslit coupler.

A novel type of multiple-wavelength focusing plasmonic coupler based on a nonperiodic nanoslit array is designed and experimentally demonstrated. An array of nanoslits patterned on a thin metal film is used to couple free-space light into surface plasmon polaritons (SPPs) and simultaneously focus different-wavelength SPPs into arbitrary predefined locations in the two-dimensional plane. We design and fabricate a compact triplexer on a glass substrate with an integrated silicon photodetector. The photocurrent spectra demonstrate that the incident light is effectively coupled to SPPs and routed into three different focal spots depending on the wavelength. The proposed scheme provides a simple method of building wavelength-division multiplexing and spectral filtering elements, integrated with other plasmonic and optoelectronic devices.

Family monetary incentives as a value-based care model for oral hygiene: rationale and design of the BEhavioral EConomics for Oral health iNnovation (BEECON) trial.

BACKGROUND: Effective prevention-focused, value-based strategies are needed to improve oral health. Despite evidence that monetary incentives can motivate healthy behavior, well-powered studies have yet to examine incentives for improving children's oral hygiene. AIM: Describe the rationale and design of the BEhavioral EConomics for Oral health iNnovation (BEECON) trial, which tests lottery-based monetary incentives as a consumer-oriented, value-based care model for improving children's oral hygiene. DESIGN: Phase II, stratified, permuted block randomized, controlled, two-arm, parallel groups, prevention trial. SETTING: Study visits occur at three Los Angeles, CA health clinics. PARTICIPANTS: Two hundred and forty-four parent-child dyads with a child aged 6-48 months. INTERVENTIONS: Eligible dyads were randomized in equal allocation to one of two groups: lottery incentive group or waitlist (delayed incentive) control group. Weekly lottery incentives were offered for 6 months based on Bluetooth-recorded toothbrushing frequency. Both groups received weekly text message feedback on toothbrushing performance. OUTCOMES: The primary outcome was toothbrushing performance from baseline to 6 months, measured as the mean number of qualifying half-day Bluetooth-recorded episodes per week when the child's teeth were brushed. Secondary outcomes included toothbrushing performance sustainability through 12 months and dental caries status. CONCLUSIONS: BEECON offers a consumer-oriented approach to promoting value-based oral health care. We hypothesize that lottery-based incentives can improve oral hygiene in young children. Study results will inform programming efforts to enhance oral disease prevention in young children. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03576326.

Monetary incentives for improving smartphone-measured oral hygiene behaviors in young children: A randomized pilot trial.

AIMS: To assess feasibility, acceptability, and early efficacy of monetary incentive-based interventions on fostering oral hygiene in young children measured with a Bluetooth-enabled toothbrush and smartphone application. DESIGN: A stratified, parallel-group, three-arm individually randomized controlled pilot trial. SETTING: Two Los Angeles area Early Head Start (EHS) sites. PARTICIPANTS: 36 parent-child dyads enrolled in an EHS home visit program for 0-3 year olds. INTERVENTIONS: Eligible dyads, within strata and permuted blocks, were randomized in equal allocation to one of three groups: waitlist (delayed monetary incentive) control group, fixed monetary incentive package, or lottery monetary incentive package. The intervention lasted 8 weeks. OUTCOMES: Primary outcomes were a) toothbrushing performance: mean number of Bluetooth-recorded half-day episodes per week when the child's teeth were brushed, and b) dental visit by the 2-month follow-up among children with no prior dental visit. The a priori milestone of 20% more frequent toothbrushing identified the intervention for a subsequent trial. Feasibility and acceptability measures were also assessed, including frequency of parents syncing the Bluetooth-enabled toothbrush to the smartphone application and plaque measurement from digital photographs. FINDINGS: Digital monitoring of toothbrushing was feasible. Mean number of weekly toothbrushing episodes over 8 weeks was 3.9 in the control group, 4.1 in the fixed incentive group, and 6.0 in the lottery incentive group. The lottery group had 53% more frequent toothbrushing than the control group and 47% more frequent toothbrushing than the fixed group. Exploratory analyses showed effects concentrated among children ≤24 months. Follow-up dental visit attendance was similar across groups. iPhone 7 more reliably captured evaluable images than Photomed Cannon G16. CONCLUSIONS: Trial protocol and outcome measures were deemed feasible and acceptable. Results informed the study protocol for a fully powered trial of lottery incentives versus a delayed control using the smart toothbrush and remote digital incentive program administration. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03862443.

Planar lenses based on nanoscale slit arrays in a metallic film.

We experimentally demonstrate planar lenses based on nanoscale slit arrays in a metallic film. Our lens structures consist of optically thick gold films with micron-size arrays of closely spaced, nanoscale slits of varying widths milled using a focused ion beam. We find excellent agreement between electromagnetic simulations of the design and confocal measurements on manufactured structures. We provide guidelines for lens design and show how actual lens behavior deviates from simple theory.