Experimental and Theoretical Exploration of the Kinetics and Thermodynamics of the Nucleophile-Induced Fragmentation of Ylidenenorbornadiene Carboxylates.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with thiol nucleophiles to yield mixtures of four to eight diastereomers depending on the symmetry of the YND substrate. The mixtures of diastereomers fragment via a retro-[4 + 2] cycloaddition with a large variation in rate, with half-lives ranging from 16 to 11,000 min at 80 °C. The diastereomer-enriched samples of propane thiol adducts [YND-propanethiol (PTs)] were isolated and identified by nuclear Overhauser effect spectroscopy (NOESY) correlations. Simulated kinetics were used to extrapolate the rate constants of individual diastereomers from the observed rate data, and it correlated well with rate constants measured directly and from isolated diastereomer-enriched samples. The individual diastereomers of a model system fragment at differing rates with half-lives ranging from 5 to 44 min in CDCl3. Density functional theory calculations were performed to investigate the mechanism of fragmentation and support an asynchronous retro-[4 + 2] cycloaddition transition state. The computations generally correlated well with the observed free energies of activation for four diastereomers of the model system as a whole, within 2.6 kcal/mol. However, the observed order of the fragmentation rates across the set of diastereomers deviated from the computational results. YNDs display wide variability in the rate of fragmentation, dependent on the stereoelectronics of the ylidene substituents. A Hammett study showed that the electron-rich aromatic rings attached to the ylidene bridge increase the fragmentation rate, while electron-deficient systems slow fragmentation rates.

Ylidenenorbornadiene Carboxylates: Experimental Kinetic Analysis of a Nucleophile-Induced Fragmentation Reaction.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with beta-mercaptoethanol to yield a mixture of four diastereomers. These four diastereomers fragment via a retro-[4 + 2] cycloaddition at differing rates. A simulated kinetics approach extrapolated the rate constants of the diastereomers from the observed rate data. YNDs display wide variability in rate of fragmentation, dependent on the stereoelectronics of the ylidene substituents. A substrate containing one carboxylic ester proved exceptionally stable to fragmentation.

The influence of siblings on ethnically diverse children's gender typing across early development.

Most U.S. children grow up with siblings. Theory and prior work suggest that older siblings are important sources of gender-related information and socialization. However, few studies have investigated the patterns of these associations longitudinally across early childhood. The present study examines the influence of sibling presence and gender composition on the trajectory of early gender-typed behavior and appearance in children from age 2 through 6 in a diverse sample of Dominican American (36%), African American (33%), and Mexican American (31%) mother-child dyads (N = 232; 112 girls, 120 boys) from low-income households in New York City (M = $20,459, SD = 14,632). Results found that children without older siblings spent more time playing with counterstereotypical toys and their mothers' reports indicated similar behavior over the past month (e.g., a girl playing with toy vehicles and balls; a boy playing with toy kitchen sets and dolls) than children with older siblings. Further, children with at least one other-gender sibling (e.g., a girl with an older brother) played more frequently with counterstereotypical toys compared with children with only same-gender siblings (e.g., a girl with only older sisters). Results on the relation between siblings and gender appearance were mixed. Older siblings may thus influence early trajectories of important gender domains (e.g., toy play), which can have various long-term implications for developing skills and interests. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Regulatory Focus and Substance Use in Adolescents: Protective Effects of Prevention Orientation.

BACKGROUND: Substance use is a major risk factor for negative health and functioning outcomes among middle schoolers. The purpose of this study was to assess whether individual differences in the adolescents' goal orientation are associated with elevated or attenuated risk for substance use. Regulatory focus theory stipulates that individuals vary in their strength of orientation toward promotion goals ("making good things happen") and prevention goals ("keeping bad things from happening"). Objectives: We sought to examine the association between individual differences in regulatory focus and adolescents' reports of their own and their friends' substance use. Methods: Participants were 241 seventh grade students who completed measures of regulatory focus (promotion and prevention orientation), self-reported substance use, perceived substance use habits of peers, and demographics. Logistic regression models were used to examine adjusted odds of lifetime tobacco use, alcohol use, and marijuana use for both participants' own use and their reports of friends' use. Results: Prevention orientation was associated with lower odds of all self-reported lifetime substance use outcomes (tobacco, alcohol, and marijuana). Prevention orientation was also associated with lower odds of reporting all types of substance use among friends. Promotion orientation was not associated with any self-reported substance use outcome, and was only associated with higher odds of reporting lifetime alcohol use among friends. Conclusions: These findings underscore the importance of regulatory focus as it relates to adolescent substance use. Future research may seek to incorporate regulatory focus within interventions intended to prevent or delay initiation of substance use in adolescents.

Raising Grateful Children One Day at a Time.

The current study examined micro-developmental processes related to the socialization of children's gratitude. Specifically, we tested whether parents who engage in more frequent daily socialization practices targeting children's gratitude reported more frequent displays of gratitude by their children after controlling for potential confounds (i.e., parents' own gratitude, sensitive parenting, and children's socio-emotional functioning). The sample of 101 parent-child dyads completed a baseline lab visit followed by a seven-day diary study. Using multi-level modeling, we found that parents who engaged in more frequent gratitude socialization acts (versus parents with fewer socialization acts) reported more frequent displays of gratitude by their children across the seven-day period (a between-dyad effect). We also found that on days when a parent engaged in more socialization acts than usual (versus days when that parent engaged in fewer acts than usual) parents reported relative increases in gratitude displays by their children (a within-dyad effect). These findings show that parent socialization acts are associated with children's displayed gratitude and point to the need for future work to explore reactive and proactive parent-child interactions that may underlie these associations as well as associations between micro-developmental and macro-developmental processes.

Grateful parents raising grateful children: Niche selection and the socialization of child gratitude.

Given that children's exposure to gratitude-related activities may be one way that parents can socialize gratitude in their children, we examined whether parents' niche selection (i.e., tendency to choose perceived gratitude-inducing activities for their children) mediates the association between parents' reports of their own and their children's gratitude. Parent-child dyads (N =101; children aged 6-9; 52% girls; 80% Caucasian; 85% mothers) participated in a laboratory visit and parents also completed a seven-day online diary regarding children's gratitude. Decomposing specific indirect effects within a structural equation model, we found that parents high in gratitude were more likely to set goals to use niche selection as a gratitude socialization strategy, and thereby more likely to place their children in gratitude-related activities. Placement in these activities, in turn, was associated with more frequent expression of gratitude in children. We describe future directions for research on parents' role in socializing gratitude in their children.

Natural Peer Leaders as Substance Use Prevention Agents: the Teens' Life Choice Project.

In adolescent social groups, natural peer leaders have been found to engage in more frequent experimentation with substance use and to possess disproportionate power to affect the behavior and social choices of their associated peer followers. In the current exploratory study, we used sociometrics and social cognitive mapping to identify natural leaders of cliques in a seventh grade population and invited the leaders to develop anti-drug presentations for an audience of younger peers. The program employed social-psychological approaches directed at having leaders proceed from extrinsic inducements to intrinsic identification with their persuasive products in the context of the group intervention process. The goals of the intervention were to induce substance resistant self-persuasion in the leaders and to produce a spread of this resistance effect to their peer followers. To test the intervention, we compared the substance use behaviors of the selected leaders and their peers to a control cohort. The study found preliminary support that the intervention produced changes in the substance use behavior among the leaders who participated in the intervention, but did not detect a spread to non-leader peers in the short term. This descriptive study speaks to the plausibility of employing self-persuasion paradigms to bring about change in high-risk behaviors among highly central adolescents. In addition, it highlights the viability of applying social psychological principles to prevention work and calls for more research in this area.

Characterization of Reagent Pencils for Deposition of Reagents onto Paper-Based Microfluidic Devices.

Reagent pencils allow for solvent-free deposition of reagents onto paper-based microfluidic devices. The pencils are portable, easy to use, extend the shelf-life of reagents, and offer a platform for customizing diagnostic devices at the point of care. In this work, reagent pencils were characterized by measuring the wear resistance of pencil cores made from polyethylene glycols (PEGs) with different molecular weights and incorporating various concentrations of three different reagents using a standard pin abrasion test, as well as by measuring the efficiency of reagent delivery from the pencils to the test zones of paper-based microfluidic devices using absorption spectroscopy and digital image colorimetry. The molecular weight of the PEG, concentration of the reagent, and the molecular weight of the reagent were all found to have an inverse correlation with the wear of the pencil cores, but the amount of reagent delivered to the test zone of a device correlated most strongly with the concentration of the reagent in the pencil core. Up to 49% of the total reagent deposited on a device with a pencil was released into the test zone, compared to 58% for reagents deposited from a solution. The results suggest that reagent pencils can be prepared for a variety of reagents using PEGs with molecular weights in the range of 2000 to 6000 g/mol.

Reagent pencils: a new technique for solvent-free deposition of reagents onto paper-based microfluidic devices.

Custom-made pencils containing reagents dispersed in a solid matrix were developed to enable rapid and solvent-free deposition of reagents onto membrane-based fluidic devices. The technique is as simple as drawing with the reagent pencils on a device. When aqueous samples are added to the device, the reagents dissolve from the pencil matrix and become available to react with analytes in the sample. Colorimetric glucose assays conducted on devices prepared using reagent pencils had comparable accuracy and precision to assays conducted on conventional devices prepared with reagents deposited from solution. Most importantly, sensitive reagents, such as enzymes, are stable in the pencils under ambient conditions, and no significant decrease in the activity of the enzyme horseradish peroxidase stored in a pencil was observed after 63 days. Reagent pencils offer a new option for preparing and customizing diagnostic tests at the point of care without the need for specialized equipment.

Conscientiousness in life course context: a commentary.

In this commentary, the common themes from the interesting articles in this special section of Developmental Psychology are considered as they illuminate the potential ontogenetic sources of the conscientiousness-well-being-longevity interconnections that have emerged in recent research. In particular, consideration is given to the changing nature of the expression of conscientiousness over the life course and the importance of the causally linked chain of developmental events associated with the sustenance of this trait from early childhood to later life. Methodological as well as conceptual issues are part of the common thematic analysis provided. In addition, several more or less neglected issues are addressed in the commentary. These include an examination of the potential roles of self-presentation social context and social aggregation in the developmentally emergent conscientiousness-well-being relationship. Further, the potential downside of the moral tinge of the conscientiousness construct is considered, as is the cultural variation in the benefits of conscientiousness to well-being. Finally, the applied significance of research on the conscientiousness-well-being link to health promotion over the life course is addressed. The commentary concludes with reflections on the transformation of 1970s trait-like conceptions as unbending tautological predictors of behavior into the situationally and developmentally nuanced conceptions of conscientiousness provided in these collected articles.

Early risk factors for alcohol use across high school and its covariation with deviant friends.

OBJECTIVE: Past research has associated childhood characteristics and experiences with alcohol use at single time points in adolescence. Other work has focused on drinking trajectories across adolescence but with risk factors typically no earlier than middle or high school. Similarly, although the connection between underage drinking and affiliation with deviant friends is well established, early risk factors for their covariation across adolescence are uncertain. The present study examines the influence of early individual and contextual factors on (a) trajectories across high school of per-occasion alcohol use and (b) the covariation of alcohol use and deviant friends over time. METHOD: In a longitudinal community sample (n = 374; 51% female), temperamental disinhibition, authoritarian and authoritative parenting, and parental alcohol use were assessed during childhood, and adolescents reported on alcohol use and affiliation with deviant friends in the spring of Grades 9, 10, 11, and 12. RESULTS: Early parental alcohol use predicted the intercept of adolescent drinking. Subsequent patterns of adolescent alcohol use were predicted by sex and interactions of sex and childhood disinhibition with early authoritarian parenting. Additionally, childhood disinhibition interacted with parental alcohol use to moderate the covariation of drinking and deviant friends. CONCLUSIONS: These findings highlight early individual and contextual risk factors for alcohol use across high school, extending previous work and underscoring the importance of developmental approaches and longitudinal techniques for understanding patterns of growth in underage drinking.

Polymer brushes under high load.

Polymer coatings are frequently used to provide repulsive forces between surfaces in solution. After 25 years of design and study, a quantitative model to explain and predict repulsion under strong compression is still lacking. Here, we combine experiments, simulations, and theory to study polymer coatings under high loads and demonstrate a validated model for the repulsive forces, proposing that this universal behavior can be predicted from the polymer solution properties.

Synthesis and characterization of ionic polymer networks in a room-temperature ionic liquid.

Ionic liquid gels (ILGs) for potential use in ion transport and separation applications were generated via a free radical copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and N,N'-methylene(bis)acrylamide (MBA) using 1-ethyl-3-methylimidazolium ethylsulfate (IL) as a room temperature ionic liquid solvent medium. The AMPS and MBA monomer solubility window in the IL in the temperature range of 25 to 65 °C was determined. In situ ATR-FTIR showed near complete conversion of monomers to a cross-linked polymer network. ILGs with glass transition temperatures (T(g)s) near -50 °C were generated with T(g) decreasing with increasing IL content. The elastic moduli in compression (200 to 6600 kPa) decreased with increasing IL content and increasing AMPS content while the conductivities (0.35 to 2.14 mS cm⁻¹) increased with increasing IL content and decreasing MBA content. The polymer-IL interaction parameter (χ) (0.48 to 0.55) was determined via a modified version of the Bray and Merrill equation.

Directing the deposition of ferromagnetic cobalt onto Pt-tipped CdSe@CdS nanorods: synthetic and mechanistic insights.

A methodology providing access to dumbbell-tipped, metal-semiconductor and metal oxide-semiconductor heterostructured nanorods has been developed. The synthesis and characterization of CdSe@CdS nanorods incorporating ferromagnetic cobalt nanoinclusions at both nanorod termini (i.e., dumbbell morphology) are presented. The key step in the synthesis of these heterostructured nanorods was the decoration of CdSe@CdS nanorods with platinum nanoparticle tips, which promoted the deposition of metallic CoNPs onto Pt-tipped CdSe@CdS nanorods. Cobalt nanoparticle tips were then selectively oxidized to afford CdSe@CdS nanorods with cobalt oxide domains at both termini. In the case of longer cobalt-tipped nanorods, heterostructured nanorods were observed to self-organize into complex dipolar assemblies, which formed as a consequence of magnetic associations of terminal CoNP tips. Colloidal polymerization of these cobalt-tipped nanorods afforded fused nanorod assemblies from the oxidation of cobalt nanoparticle tips at the ends of nanorods via the nanoscale Kirkendall effect. Wurtzite CdS nanorods survived both the deposition of metallic CoNP tips and conversion into cobalt oxide phases, as confirmed by both XRD and HRTEM analysis. A series of CdSe@CdS nanorods of four different lengths ranging from 40 to 174 nm and comparable diameters (6-7 nm) were prepared and modified with both cobalt and cobalt oxide tips. The total synthesis of these heterostructured nanorods required five steps from commercially available reagents. Key synthetic considerations are discussed, with particular emphasis on reporting isolated yields of all intermediates and products from scale up of intermediate precursors.

Evaluating the impact of a substance use intervention program on the peer status and influence of adolescent peer leaders.

The current study involved an examination of the impact of a peer-led substance use intervention program on the peer leaders beyond the substance use-related goals of the intervention. Specifically, unintended consequences of an adult-sanctioned intervention on the targeted peer leader change agents were investigated, including whether their participation affected their peer status, social influence, or self perceptions. Twenty-two 7th grade peer-identified intervention leaders were compared to 22 control leaders (who did not experience the intervention) and 146 cohort peers. Three groups of measures were employed: sociometric and behavioral nominations, social cognitive mapping, and leadership self-perceptions. Results indicated that unintended consequences appear to be a legitimate concern for females. Female intervention leaders declined in perceived popularity and liked most nominations over time, whereas males increased in total leader nominations. Explanations for these results are discussed and further directions suggested.

Academic Giftedness and Alcohol Use in Early Adolescence.

Adolescence is a period of development particularly vulnerable to the effects of alcohol use, with recent studies underscoring alcohol's effects on adolescent brain development. Despite the alarming rates and consequences of adolescent alcohol use, gifted adolescents are often overlooked as being at risk for early alcohol use. Although gifted adolescents may possess protective factors that likely inhibit the use of alcohol, some gifted youth may be vulnerable to initiating alcohol use during adolescence as experimenting with alcohol may be one way gifted youth choose to compensate for the social price (whether real or perceived) of their academic talents. To address the dearth of research on alcohol use among gifted adolescents the current study (a) examined the extent to which gifted adolescents use alcohol relative to their nongifted peers and (b) examined the adjustment profile of gifted adolescents who had tried alcohol relative to nongifted adolescents who tried alcohol as well as gifted and nongifted abstainers. More than 300 students in seventh grade (42.5% gifted) participated in the present study. Results indicated gifted students have, in fact, tried alcohol at rates that do not differ from nongifted students. Although trying alcohol was generally associated with negative adjustment, giftedness served as a moderating factor such that gifted students who had tried alcohol were less at risk than their nongifted peers. However, evidence also suggests that gifted adolescents who tried alcohol may be a part of a peer context that promotes substance use, which may place these youth at risk for adjustment difficulties in the future.

Maternal socialization goals, parenting styles, and social-emotional adjustment among Chinese and European American young adults: testing a mediation model.

The authors compared the associations among perceived maternal socialization goals (self-development, filial piety, and collectivism), perceived maternal parenting styles (authoritative, authoritarian, and training), and the social-emotional adjustment (self-esteem, academic self-efficacy, and depression) between Chinese and European American young adults. The mediation processes in which socialization goals relate to young adults' adjustment outcomes through parenting styles were examined. Results showed that European American participants perceived higher maternal self-development socialization goals, whereas Chinese participants perceived higher maternal collectivism socialization goals as well as more authoritarian parenting. Cross-cultural similarities were found in the associations between perceived maternal authoritative parenting and socioemotional adjustment (e.g., higher self-esteem and higher academic self-efficacy) across the two cultural groups. However, perceived maternal authoritarian and training parenting styles were found only to be related to Chinese participants' adjustment (e.g., higher academic self-efficacy and lower depression). The mediation analyses showed that authoritative parenting significantly mediated the positive associations between the self-development and collectivism goal and socioemotional adjustment for both cultural groups. Additionally, training parenting significantly mediated the positive association between the filial piety goal and young adults' academic self-efficacy for the Chinese group only. Findings of this study highlight the importance of examining parental socialization goals in cross-cultural parenting research.

Alcohol-consumption trajectories and associated characteristics among adults older than age 50.

OBJECTIVE: This study examined changes in drinking behavior after age 50 and baseline personal characteristics and subsequent life events associated with different alcohol-consumption trajectories during a 14-year follow-up period. METHOD: Data were taken from the Health and Retirement Study. The study sample included individuals ages 51-61 in 1992 who survived the sample period (1992-2006) and had at least five interviews with alcohol consumption information, yielding an analysis sample of 6,787 (3,760 women). We employed linear regression to determine drinking trajectories over 1992-2006. Based on these findings, each sample person was classified into one of five drinking categories. We used multinomial logit analysis to assess the relationship between personal demographic, income, health, and attitudinal characteristics as well as life events and drinking-trajectory category. RESULTS: Overall, alcohol consumption declined. However, rates of decline differed appreciably among sample persons, and for a minority, alcohol consumption increased. Persons with increasing consumption over time were more likely to be affluent (relative-risk ratio [RRR] = 1.09, 95% CI [1.05, 1.12]), highly educated (RRR = 1.20, 95% CI [1.09, 1.31]), male, White (RRR = 3.54, 95% CI [1.01, 12.39]), unmarried, less religious, and in excellent to good health. A history of problem drinking before baseline was associated with increases in alcohol use, whereas the reverse was true for persons with histories of few or no drinking problems. CONCLUSIONS: There are substantial differences in drinking trajectories at the individual level in midlife and late life. A problem-drinking history is predictive of alcohol consumption patterns in later life.

Controlling surface energy and wetability with Diels-Alder chemistry.

Reversible Diels-Alder chemistry was utilized to manipulate the surface energy of glass substrates. Hydrophobic dieneophiles were prepared and attached to glass slides and capillaries to yield a nonwetting surface. Thermal treatment of the surfaces cleaved the Diels-Alder linkage, and resulted in the fabrication of a hydrophilic surface. Preliminary analysis utilized contact angle (CA) measurements to monitor the change in surface energy, and observed a hydrophilic state (CA - 70 +/- 3 degrees) before attachment of the dieneophile to a hydrophobic state (CA - 101 +/- 9 degrees) followed by regeneration of the hydrophilic state (CA - 70 +/- 6 degrees) upon cleavage of the Diels-Alder linkage. The treatments were then applied to glass capillaries, with effective treatment confirmed by fluid column measurements. Patterned treatments were also demonstrated to provide effective flow gating. Finally, attempts to create self-pressurizing capillaries were unsuccessful due to pronounced contact angle hysteresis for the hydrophobic surface treatment.

Racial differences in the relationship between alcohol consumption in early adulthood and occupational attainment at midlife.

OBJECTIVES: We assessed the relationship between alcohol consumption in young adulthood (ages 18-30 years) and occupational success 15 years later among Blacks and Whites. METHODS: We analyzed data from the Coronary Artery Risk Development in Young Adults Study on employment status and occupational prestige at year 15 from baseline. The primary predictor was weekly alcohol use at baseline, after stratification by race and adjustment for socioeconomic factors. RESULTS: We detected racial differences in the relationship between alcohol use in early adulthood and employment status at midlife. Blacks who were very heavy drinkers at baseline were more than 4 times as likely as Blacks who were occasional drinkers to be unemployed at year 15 (odds ratio [OR]=4.34; 95% confidence interval [CI]=2.22, 8.47). We found no statistically significant relationship among Whites. Occupational prestige at midlife was negatively related to very heavy drinking, but after adjustment for marital status, active coping, life stress, and educational attainment, this relationship was statistically significant only among Blacks. CONCLUSIONS: Heavy drinking during young adulthood was negatively associated with labor market success at midlife, especially among Blacks.