The Influence of Electronic Polarization on Nonlinear Optical Spectroscopy.

The environment surrounding a chromophore can dramatically affect the energy absorption and relaxation process, as manifested in optical spectra. Simulations of nonlinear optical spectroscopy, such as two-dimensional electronic spectroscopy (2DES) and transient absorption (TA), will be influenced by the computational model of the environment. We here compare a fixed point charge molecular mechanics model and a quantum mechanical (QM) model of the environment in computed 2DES and TA spectra of Nile red in water and the chromophore of photoactive yellow protein (PYP) in water and protein environments. In addition to simulating these nonlinear optical spectra, we directly juxtapose the computed excitation energy correlation function to the dynamic Stokes shift function often used to analyze environment dynamics. Overall, we find that for the three systems studied here the mutual electronic polarization provided by the QM environment manifests in broader 2DES signals, as well as a larger reorganization energy and a larger static Stokes shift due to stronger coupling between the chromophore and the environment.

Paradigms of frustration in superionic solid electrolytes.

Superionic solid electrolytes have widespread use in energy devices, but the fundamental motivations for fast ion conduction are often elusive. In this Perspective, we draw upon atomistic simulations of a wide range of superionic conductors to illustrate some ways frustration can lower diffusion cation barriers in solids. Based on our studies of halides, oxides, sulfides and hydroborates and a survey of published reports, we classify three types of frustration that create competition between different local atomic preferences, thereby flattening the diffusive energy landscape. These include chemical frustration, which derives from competing factors in the anion-cation interaction; structural frustration, which arises from lattice arrangements that induce site distortion or prevent cation ordering; and dynamical frustration, which is associated with temporary fluctuations in the energy landscape due to anion reorientation or cation reconfiguration. For each class of frustration, we provide detailed simulation analyses of various materials to show how ion mobility is facilitated, resulting in stabilizing factors that are both entropic and enthalpic in origin. We propose the use of these categories as a general construct for classifying frustration in superionic conductors and discuss implications for future development of suitable descriptors and improvement strategies. This article is part of the Theo Murphy meeting issue 'Understanding fast-ion conduction in solid electrolytes'.

Vibronic and Environmental Effects in Simulations of Optical Spectroscopy.

Including both environmental and vibronic effects is important for accurate simulation of optical spectra, but combining these effects remains computationally challenging. We outline two approaches that consider both the explicit atomistic environment and the vibronic transitions. Both phenomena are responsible for spectral shapes in linear spectroscopy and the electronic evolution measured in nonlinear spectroscopy. The first approach utilizes snapshots of chromophore-environment configurations for which chromophore normal modes are determined. We outline various approximations for this static approach that assumes harmonic potentials and ignores dynamic system-environment coupling. The second approach obtains excitation energies for a series of time-correlated snapshots. This dynamic approach relies on the accurate truncation of the cumulant expansion but treats the dynamics of the chromophore and the environment on equal footing. Both approaches show significant potential for making strides toward more accurate optical spectroscopy simulations of complex condensed phase systems.

Diabetes symptoms predictors of health-related quality of life in adolescents and young adults with type 1 or type 2 diabetes.

OBJECTIVES: The objective was to investigate the patient-reported diabetes symptoms predictors of generic health-related quality of life (HRQOL) in adolescents and young adults (AYA) with type 1 or type 2 diabetes. METHODS: The 15-item PedsQL™ 3.2 Diabetes Module Diabetes Symptoms Summary Score and PedsQL™ 4.0 Generic Core Scales were completed in a 10-site national field test study by 513 AYA ages 13-25 years with type 1 (n = 424) or type 2 (n = 89) diabetes. Diabetes symptoms were tested for bivariate and multivariate linear associations with generic HRQOL. RESULTS: Diabetes symptoms were associated with decreased HRQOL in bivariate analyses. In predictive analytics models utilizing hierarchical multiple regression analyses controlling for relevant demographic and clinical covariates, diabetes symptoms accounted for 38 and 39% of the variance in patient-reported generic HRQOL for type 1 and type 2 diabetes, respectively, reflecting large effect sizes. The diabetes symptoms facets hyperglycemia symptoms, hypoglycemia symptoms, and nonspecific diabetes symptoms individually accounted for a significant percentage of the variance in separate exploratory predictive analytics models after controlling for demographic and clinical covariates, with small-to-large effect sizes. CONCLUSIONS: Diabetes symptoms are potentially modifiable predictors of generic HRQOL in AYA with diabetes. Identifying specific diabetes symptoms or symptoms facets that are the most important predictors from the patient perspective facilitates a patient-centered approach in clinical research, clinical trials, and practice designed to enhance overall generic HRQOL in AYA with diabetes.

Health-related Quality of Life in Infants With Chronic Liver Disease.

OBJECTIVE: The objective of the present study was to report on the health-related quality of life (HRQOL) of infants with chronic liver disease using the PedsQL (Pediatric Quality of Life Inventory) Infant Scales. METHODS: The 36-item (ages 1-12 months) and 45-item (ages 13-24 months) PedsQL Infant Scales (physical functioning, physical symptoms, emotional functioning, social functioning, cognitive functioning) were completed by 50 parents of infants with chronic liver disease. RESULTS: Infants ages 1 to 12 months had significantly lower HRQOL scores compared with a matched healthy sample. Infants 13 to 24 months trended to lower physical HRQOL scores that did not reach statistical significance. Recent hospitalizations had an impact on the majority of HRQOL subscales, as did ascites, and failure to thrive. CONCLUSIONS: Infants ages 1 to 12 months with chronic liver disease demonstrate lower HRQOL compared with healthy children with physical subscales being most severely affected. The PedsQL Infant Scales allow the definition of HRQOL during a critical period of an infants' development that has been heretofore difficult to measure.

Association of anxiety and ODD/CD in children with and without ADHD.

The goal of this study is to examine levels of oppositional defiant disorder (ODD) and conduct disorder (CD) in four groups of children: attention-deficit/hyperactivity disorder (ADHD) only, anxiety only, ADHD and anxiety, and controls (i.e., non-ADHD youth). Although children with ADHD exhibit more ODD and CD than non-ADHD youth, it is unknown if anxiety is associated with increased or decreased ODD and CD in children with ADHD. We examined parent and teacher ratings of ODD and CD from the Disruptive Behavior Disorder Rating Scale in 203 school age children (ages 6-9); 70% were male, and 47% were Caucasian. Children were divided into four diagnostic groups based on ADHD and anxiety status from the Diagnostic Interview Scale for Children. According to parents, children with ADHD and anxiety had the highest levels of ODD/CD, followed by children with ADHD only (i.e., without anxiety). Children with anxiety only and controls had lowest ODD and CD scores, and these groups did not differ from each other. The same patterns were found according to teacher report, except that the anxiety only group had significantly lower levels of ODD than non-ADHD controls. Further, combined type ADHD youth with anxiety exhibited the highest levels of ODD and CD compared to all other groups. Comorbid anxiety may strengthen the association of ADHD and ODD/CD, particularly in the combined subtype. We discuss the importance of comorbid anxiety to the development of externalizing problems as well as potential explanatory factors underlying elevated ODD and CD among children with ADHD and anxiety.

Association of comorbid anxiety with social functioning in school-age children with and without attention-deficit/hyperactivity disorder (ADHD).

Although attention-deficit/hyperactivity disorder (ADHD) is frequently comorbid with disruptive behavior disorders, less is known about ADHD and comorbid anxiety. To improve understanding about the association of anxiety and social functioning, we studied 223 6 to 9 year-old ethnically diverse boys and girls (M=7.4 years) with and without ADHD. According to parents, children with ADHD and anxiety (n=46) and ADHD only (n=71) were consistently less socially competent than comparison children (i.e., no anxiety and ADHD: n=80) and children with anxiety only (n=26), who did not differ from one another. A similar pattern emerged for teacher ratings where youth with ADHD only and ADHD with anxiety exhibited the most social problems, but they did not differ from each other. These data suggest that comorbid anxiety does not exacerbate social dysfunction among 6 to 9 year-old children with ADHD. We consider findings within a developmental psychopathology framework to further understand social development in children with ADHD and anxiety.