Multivalency in a Dendritic Host-Guest System.

Multivalency is an important instrument in the supramolecular chemistry toolkit for the creation of strong specific interactions. In this paper we investigate the multivalency effect in a dendritic host-guest system using molecular dynamics simulations. Specifically, we consider urea-adamantyl decorated poly(propyleneimine) dendrimers that together with compatible mono-, bi-, and tetravalent ureidoacetic acid guests can form dynamic patchy nanoparticles.

The 100-plus Study of cognitively healthy centenarians: rationale, design and cohort description.

Although the incidence of dementia increases exponentially with age, some individuals reach more than 100 years with fully retained cognitive abilities. To identify the characteristics associated with the escape or delay of cognitive decline, we initiated the 100-plus Study ( www.100plus.

A Randomized Effectiveness Trial of a Behavioral Teacher Program Targeting ADHD Symptoms.

Objective: This study investigated the effectiveness of the Positivity & Rules Program (PR program), a behavioral teacher program targeting ADHD symptoms in the classroom involving both student-focused and classroom-focused programs.

Method: Primary school children with ADHD symptoms ( N = 114) were randomly assigned to the PR program ( n = 58) or control group ( n = 56). Teacher and parent ratings were used to assess behavioral, social, and emotional functioning at baseline, during and after the intervention.

Coarse-grained simulations of poly(propylene imine) dendrimers in solution.

The behavior of poly(propylene imine) (PPI) dendrimers in concentrated solutions has been investigated using molecular dynamics simulations containing up to a thousand PPI dendrimers of generation 4 or 5 in explicit water. To deal with large system sizes and time scales required to study the solutions over a wide range of dendrimer concentrations, a previously published coarse-grained model was applied. Simulation results on the radius of gyration, structure factor, intermolecular spacing, dendrimer interpenetration, and water penetration are compared with available experimental data, providing a clear concentration dependent molecular picture of PPI dendrimers.

Association between impulsivity, reward responsiveness and body mass index in children.

Background: Childhood obesity is a major health problem. An association between children's body mass index (BMI) and overeating has been established, but mechanisms leading to overeating are poorly understood. The personality characteristics impulsivity and reward responsiveness may be involved in the tendency to overeat.