Bromide-containing impurities were found to decrease the thermal stability of quaternary alkyl ammonium-modified layered silicates. Improved purification procedures completely removed bromide and led to a 20°C to >100°C increase in organic modified layered silicate thermal stability. Using mass spectrometry and thermal and electrochemical analysis, N,N-dimethyl-N,N-dioctadecyl quaternary ammonium-modified montmorillonite and fluorinated synthetic mica were found to degrade primarily through elimination and nucleophilic attack by these anions. The nature of residual bromides was identified and quantified, and the efficiency of removing these anions was found to be solvent dependent; sequential extraction, first ethanol then tetrahydrofuran, gave the best results. This exhaustive extraction method represents a viable alternative to the use of expensive, more thermally stable oniumion treatments for layered silicates.

Architected materials play an essential role in achieving next-generation electrochemical systems with unprecedented power and energy capabilities. The geometry and chemistry of architected materials can be engineered to address key areas of performance, including electrochemical kinetics and mechanics. Electrochemical kinetics impact key metrics such as power density, efficiency, and lifetime in batteries, fuel cells, and sensors. Additionally, electrochemical reactions can dramatically change material composition, which may result in large strains (in the hundreds of percent) that cause mechanical failure. In this article, we summarize advances in energy storage offered by architected materials and highlight fabrication methods used to realize these advances. We also discuss electrochemistry as an enabling tool for architected materials with functionality beyond energy storage and sensing.

We previously demonstrated that electrode architectures comprising nanoscale birnessite-like MnOx affixed to three-dimensional carbon nanofoam (CNF) scaffolds offer performance advantages when used as cathodes in rechargeable zinc-ion cells. To discern chemical and physical changes at the MnOx@CNF electrode upon deep charge/discharge in aqueous Zn2+-containing electrolytes, we deploy electroanalytical methods and ex situ characterization by microscopy, elemental analysis, x-ray photoelectron spectroscopy, x-ray diffraction, and x-ray pair distribution function analyses. Our findings verify that redox processes at the MnOx are accompanied by reversible precipitation/dissolution of crystalline zinc hydroxide sulfate (Zn4(OH)6(SO4)·xH2O), mediated by the more uniformly reactive electrode structure inherent to the CNF scaffold.

Objectives: Huntington’s disease (HD) is a debilitating genetic disorder characterized by motor, cognitive and psychiatric abnormalities associated with neuropathological decline. HD pathology is the result of an extended chain of CAG (cytosine, adenine, guanine) trinucleotide repetitions in the HTT gene. Clinical diagnosis of HD requires the presence of an otherwise unexplained extrapyramidal movement disorder in a participant at risk for HD. Over the past 15 years, evidence has shown that cognitive, psychiatric, and subtle motor dysfunction is evident decades before traditional motor diagnosis. This study examines the relationships among subcortical brain volumes and measures of emerging disease phenotype in prodromal HD, before clinical diagnosis. Methods: The dataset includes 34 cognitive, motor, psychiatric, and functional variables and five subcortical brain volumes from 984 prodromal HD individuals enrolled in the PREDICT HD study. Using cluster analyses, seven distinct clusters encompassing cognitive, motor, psychiatric, and functional domains were identified. Individual cluster scores were then regressed against the subcortical brain volumetric measurements. Results: Accounting for site and genetic burden (the interaction of age and CAG repeat length) smaller caudate and putamen volumes were related to clusters reflecting motor symptom severity, cognitive control, and verbal learning. Conclusions: Variable reduction of the HD phenotype using cluster analysis revealed biologically related domains of HD and are suitable for future research with this population. Our cognitive control cluster scores show sensitivity to changes in basal ganglia both within and outside the striatum that may not be captured by examining only motor scores. (JINS, 2017, 23, 159–170)

The current study sought to examine the utility of intra-individual variability (IIV) in distinguishing participants with prodromal Huntington disease (HD) from nongene-expanded controls. IIV across 15 neuropsychological tasks and within-task IIV using a self-paced timing task were compared as a single measure of processing speed (Symbol Digit Modalities Test [SDMT]) in 693 gene-expanded and 191 nongene-expanded participants from the PREDICT-HD study. After adjusting for depressive symptoms and motor functioning, individuals estimated to be closest to HD diagnosis displayed higher levels of across- and within-task variability when compared to controls and those prodromal HD participants far from disease onset (FICV(3,877)=11.25; p<.0001; FPacedTiming(3,877)=22.89; p<.0001). When prodromal HD participants closest to HD diagnosis were compared to controls, Cohen’s d effect sizes were larger in magnitude for the within-task variability measure, paced timing (−1.01), and the SDMT (−0.79) and paced tapping coefficient of variation (CV) (−0.79) compared to the measures of across-task variability [CV (0.55); intra-individual standard deviation (0.26)]. Across-task variability may be a sensitive marker of cognitive decline in individuals with prodromal HD approaching disease onset. However, individual neuropsychological tasks, including a measure of within-task variability, produced larger effect sizes than an index of across-task IIV in this sample. (JINS, 2015, 21, 8–21)

There is growing evidence that many offspring of parents with bipolar disorder (BD) will develop moderate to severe forms of psychopathology during childhood and adolescence, including thought problems. The purpose of this study was to evaluate the developmental progression of thought problems within the context of a family risk study. Repeated assessments of thought problems, spanning approximately 15 years, were conducted in offspring (N = 192 from 98 families) of parents diagnosed with BD (O-BD), unipolar depression (O-UNI), or no significant psychiatric or medical problems (O-WELL). Survival analysis showed that the O-BD group had the greatest estimated probability of developing thought problems over time, followed by O-UNI, and then O-WELL and O-BD exhibiting higher levels of persistence than O-WELL. Parent-reported thought problems in childhood and adolescence predicted a range of problems in young adulthood. Disturbances in reality testing and other atypical behaviors are likely to disrupt progression through important developmental periods and to associate with poor outcomes. These findings are likely relevant to preventing the occurrence or progression of problems in offspring of bipolar parents. The study of thought problems across development represents an important area of continued research in children at risk for development of affective disorders.

Huntington disease (HD) is associated with decline in cognition and progressive morphological changes in brain structures. Cognitive reserve may represent a mechanism by which disease-related decline may be delayed or slowed. The current study examined the relationship between cognitive reserve and longitudinal change in cognitive functioning and brain volumes among prodromal (gene expansion-positive) HD individuals. Participants were genetically confirmed individuals with prodromal HD enrolled in the PREDICT-HD study. Cognitive reserve was computed as the composite of performance on a lexical task estimating premorbid intellectual level, occupational status, and years of education. Linear mixed effects regression (LMER) was used to examine longitudinal changes on four cognitive measures and three brain volumes over approximately 6 years. Higher cognitive reserve was significantly associated with a slower rate of change on one cognitive measure (Trail Making Test, Part B) and slower rate of volume loss in two brain structures (caudate, putamen) for those estimated to be closest to motor disease onset. This relationship was not observed among those estimated to be further from motor disease onset. Our findings demonstrate a relationship between cognitive reserve and both a measure of executive functioning and integrity of certain brain structures in prodromal HD individuals. (JINS, 2013, 19, 1–12).

Ongoing technological advances in such disparate areas as consumer electronics, transportation, and energy generation and distribution are often hindered by the capabilities of current energy storage/conversion systems, thereby driving the search for high-performance power sources that are also economically viable, safe to operate, and have limited environmental impact. Electrochemical capacitors (ECs) are a class of energy-storage devices that fill the gap between the high specific energy of batteries and the high specific power of conventional electrostatic capacitors. The most widely available commercial EC, based on a symmetric configuration of two high-surface-area carbon electrodes and a nonaqueous electrolyte, delivers specific energies of up to ∼6 Whkg–1 with sub-second response times. Specific energy can be enhanced by moving to asymmetric configurations and selecting electrode materials (e.g., transition metal oxides) that store charge via rapid and reversible faradaic reactions. Asymmetric EC designs also circumvent the main limitation of aqueous electrolytes by extending their operating voltage window beyond the thermodynamic 1.2 V limit to operating voltages approaching ∼2 V, resulting in high-performance ECs that will satisfy the challenging power and energy demands of emerging technologies and in a more economically and environmentally friendly form than conventional symmetric ECs and batteries.

There is growing evidence that many offspring of bipolar parents will develop moderate to severe forms of psychopathology during childhood and adolescence. The purpose of this study was to apply growth curve models to evaluate developmental progression with regard to continuity and cascades representative within the context of a family risk study of bipolar disorder (BD). Repeated assessments of externalizing, internalizing, and thought problems, spanning more than a decade, were examined in a total of 94 offspring of parents with BD (O-BD), major depressive disorder (O-UNI), or no significant psychiatric or medical problems (O-WELL). Continuity was defined by the growth curve of the O-WELL group who exhibited low levels of problems from early childhood through late adolescence. Discontinuity, as evidenced by greater complexity of growth curves relative to the O-WELL group, was exhibited in the at- risk offspring groups for internalizing problems. Different patterns of developmental cascades were supported for the at-risk group with O-UNI showing a robust cascade from self-regulatory deficits (externalizing problems) to internalizing problems. There was also support for a cascade from self-regulatory deficits to thought problems across the entire group (with some support that this pattern was accounted for primarily by O-BD). This study not only serves to advance our understanding of the risks associated with a family history of BD, but also provides a novel approach to examining developmental cascades.

Success in the domain of work is a salient developmental task of adulthood and a key indicator of adaptive function in the evaluation of health and psychopathology. Yet few studies have examined pathways to work competence, especially with strategies testing for cumulative cascade effects over time. Cascade models spanning 20 years were tested via structural equation modeling, linking work competence in early adulthood to antecedent competence in work and other domains of competence in childhood and emerging adulthood. Data were drawn from the Project Competence longitudinal study of 205 school children followed for 20 years. Relative fit of alternative models was evaluated by the Bayesian information criterion. As hypothesized, the effectiveness of adaptive behavior in earlier age-salient developmental task domains forecasted later work competence, which also showed strong concurrent links to competence in other domains. Results suggest there are numerous pathways by which success or failure in major developmental task domains in childhood and adolescence may influence adaptation in other domains and eventually work competence, both concurrently and cumulatively over time. Cascade effects highlight the potential significance for later work competence of childhood conduct (antisocial vs. rule-abiding behavior) and social competence with peers, in addition to the ongoing role that academic attainment may have for work success. Work competence also showed considerable stability over a 10-year period during early adulthood. Implications and applications for future research and intervention are discussed.

Longitudinal growth trajectories of reading and math achievement were studied in four primary school grade cohorts (GCs) of a large urban district to examine academic risk and resilience in homeless and highly mobile (H/HM) students. Initial achievement was assessed when student cohorts were in the second, third, fourth, and fifth grades, and again 12 and 18 months later. Achievement trajectories of H/HM students were compared to low-income but nonmobile students and all other tested students in the district, controlling for four well-established covariates of achievement: sex, ethnicity, attendance, and English language skills. Both disadvantaged groups showed markedly lower initial achievement than their more advantaged peers, and H/HM students manifested the greatest risk, consistent with an expected risk gradient. Moreover, in some GCs, both disadvantaged groups showed slower growth than their relatively advantaged peers. Closer examination of H/HM student trajectories in relation to national test norms revealed striking variability, including cases of academic resilience as well as problems. H/HM students may represent a major component of “achievement gaps” in urban districts, but these students also constitute a heterogeneous group of children likely to have markedly diverse educational needs. Efforts to close gaps or enhance achievement in H/HM children require more differentiated knowledge of vulnerability and protective processes that may shape individual development and achievement.

Home baseline and laboratory stressor (Trier Social Stress Test for Children) measures of salivary cortisol were obtained from 82 participants (40 girls) aged 9, 11, 13, and 15 years. Measures of pubertal development, self-reported stress, parent reports of child depressive symptoms and fearful temperament, and cardiac measures of sympathetic and parasympathetic activity were also obtained. Significant increases in the home cortisol baselines were found with age and pubertal development. Cortisol stress reactivity differed by age group with 11-year-olds and 13-year-old boys showing blunted reactivity and 9-year-olds, 13-year-old girls, and 15-year-olds showing significant cortisol reactions. Cortisol reactivity correlated marginally with sexual maturation. Measures of sympathetic activity revealed increased sympathetic modulation with age. Higher sympathetic tone was associated with more fearful temperament, whereas greater cortisol reactivity was associated with more anxious and depressed symptoms for girls. The importance of these findings for the hypothesis that puberty-associated increases in hypothalamic–pituitary–adrenal axis activity heightens the risk of psychopathology is discussed.

Animal studies reveal that early deprivation impairs regulation of the hypothalamic–pituitary–adrenocortical (HPA) axis, potentially increasing vulnerability to stressors throughout life. To examine early deprivation effects on basal HPA axis activity in humans, basal cortisol levels were examined in 164 internationally adopted children who had experienced varying degrees of preadoption deprivation. Duration of institutional care, age at adoption, and parent ratings of preadoption neglect indexed a latent factor of Deprived Care. Adoption measures of height and weight standardized to World Health Organisation norms indexed a latent factor of Growth Delay that was viewed as another reflection of deprivation. Cortisol samples were collected 3.3–11.6 years postadoption (Md = 7.3 years) at home on 3 days approximately 30 min after wakeup and before bedtime. Both early a.m. levels and the decrease in cortisol across the day were examined. A structural equation model revealed that preadoption Deprived Care predicted Growth Delay at adoption and Growth Delay predicted higher morning cortisol levels and a larger diurnal cortisol decrease.

Patterns of continuity and change in competence and resilience over the transition to adulthood were examined in relation to adversity and psychosocial resources, with a focus on adaptive resources that may be particularly important for this transition. Variable-focused and person-focused analyses drew on data from the Project Competence longitudinal study of a school cohort followed over 20 years from childhood through emerging adulthood (EA) into the young adulthood (YA) years with excellent retention (90%). Success in age-salient and emerging developmental tasks from EA to YA was examined in a sample of 173 of the original participants with complete data on adversity, competence, and key resources. Regressions and extreme-group analyses indicated striking continuity in competence and resilience, yet also predictable change. Success in developmental tasks in EA and YA was related to core resources originating in childhood (IQ, parenting quality, socioeconomic status) and also to a set of EA adaptive resources that included planfulness/future motivation, autonomy, adult support, and coping skills. EA adaptive resources had unique predictive significance for successful transitions to adulthood, both overall and for the small group of individuals whose pattern of adaptation changed dramatically from maladaptive to resilient over the transition. Results are discussed in relation to the possibility that the transition to adulthood is a window of opportunity for changing the life course.This article is based on data collected as part of the Project Competence longitudinal study, which was initiated under the leadership of Norman Garmezy, and was supported through grants to Ann Masten, Auke Tellegen, and Norman Garmezy from the William T. Grant Foundation, the National Science Foundation (SBR-9729111), the National Institute of Mental Health (MH33222), and the University of Minnesota. Preliminary results of this study were presented at the biennial meeting of the Society for Research on Adolescence in Baltimore (March 2004). The authors gratefully acknowledge the contributions to this study by the participants, who shared their lives over time to benefit others, and by the many research team members, students, and faculty, who added ideas and data to this endeavor over the years. The authors particularly want to acknowledge the role of Doug Coatsworth in designing the emerging adulthood assessments pertinent to this article and the current members of the Project Competence research team who improved this article through their thoughtful critiques and comments as the analyses and writing progressed.

The structural and chemical heterogeneity of 2.5-nm Pt50Ru50 electrocatalysts was studied by transmission electron microscopy using selected area diffraction, lattice imaging, electron-energy loss spectroscopy, and energy-dispersive X-ray spectroscopy. The catalysts with the highest methanol oxidation activities exhibit oxidation-induced phase separation on the nanoscale to form Pt-rich metal embedded in Ru-rich hydrous and anhydrous oxide. Reduction of the oxide-on-metal samples produces a true bimetallic face-centered cubic Pt50Ru50 alloy, with 275 times lower oxidation activity.