How Colloidal Lithography Limits the Optical Quality of Plasmonic Nanohole Arrays.

Colloidal lithography utilizes self-assembled particle monolayers as lithographic masks to fabricate arrays of nanostructures by combination of directed evaporation and etching steps. This process provides complex nanostructures over macroscopic areas in a simple, convenient, and parallel fashion without requiring clean-room infrastructure and specialized equipment. The appeal of the method comes at the price of imperfections impairing the optical quality, especially for arrayed nanostructures relying on well-ordered lattices. Imperfections are often generically mentioned to rationalize the discrepancy between experimental and simulated resonances. Yet, little attention is given to detailed structure-property relationships connecting typical defects directly with the optical properties. Here, we use a correlative approach to connect nano- and microscopic defects occurring from the colloidal lithography process with the resulting local optical properties. We use nanohole arrays as a common plasmonic structure known to be sensitive to lattice imperfections. Correlative optical and electron microscopies reveal the individual role of packing order, organic impurities, and solid polymer bridges. Our findings show that simple cleaning processes with solvents and oxygen plasma already improve the optical quality but also highlight how well-controlled self-assembly processes are required for predictable optical properties of such nanostructures.

Family Socioeconomic Status and Attention Deficit/Hyperactivity Disorder in Preschool Children: The Mediating Role of Executive Function.

This study aimed to explore the relationship between family socioeconomic status (SES) and attention deficit/hyperactivity disorder (ADHD) symptoms in preschool children and the mediating role of executive function (EF). A total of 361 parents of preschool children were surveyed using the self-reported Family Situation Questionnaire, the Child Executive Functioning Inventory, and the Child Strengths and Difficulties Questionnaire. The results revealed that (1) there were significant pairwise correlations between SES, EF and its dimensions, and ADHD, except for a non-significant correlation between SES and regulation ability; (2) after controlling for preschool children's age and sex, SES directly predicted preschoolers' ADHD and EF partially mediated the association between SES and ADHD; and (3) among the EF dimensions, working memory and inhibitory ability significantly mediated the association between SES and ADHD, whereas the mediating effect of regulatory ability was not significant. These results suggest that SES can affect the ADHD of preschoolers both directly and through EF, especially through working memory and inhibitory ability. This supports the family stress model and family investment model of the relationship between SES and the development of children to some extent, and provides a reference for the early prevention of ADHD in children with low SES.

The Short-Term Impact of Animation on the Executive Function of Children Aged 4 to 7.

Research has shown that animation plays an important role in the development of children's executive function (EF), and the development of EF components, inhibitory control, working memory, and cognitive flexibility, is asynchronous. Thus, this study explores the developmental trajectories and animation features (fantasy and pacing) that influence each EF component, by examining 218 children aged 4-7. Pretest information, mainly the childhood EF inventory, was provided by parents: child's age, age of first exposure to animation, animation viewing time on weekdays and weekends, family income, and parents' education. The children in each age group were randomly divided into four groups to watch animations comprised of different animation features. After watching, their EF were measured by a day-night task, backward digit-span task, and flexible item-selection task. The results showed that the children's inhibitory control, working memory and cognitive flexibility levels all improved with age. Highly fantastical animations weakened children's performance on each subsequent EF task. Pacing had no effect on any of the components of children's EF. An interactive effect on inhibitory control was only found with fantasy in younger children; specifically, high-fantastical animations had a more pronounced short-lived weakening effect on inhibitory control in younger children (4-6 years) compared with low-fantastical animations. Future research should explore the long-term impact of content rather than the form of animation on younger children's EF.