The Challenge of Adolescent Crowd Research: Defining the Crowd

As research on adolescent crowds has increased over the past several decades, researchers appear to be confident in their claims of the consequences of crowd membership, even suggesting targeted interventions. This review of the various methods used to identify adolescents’ crowd membership suggests that this confidence may be misplaced. There are diverse methodologies used in this research area that examine different samples of adolescents belonging to each crowd. Social-type rating methods, self-identification methods, grouping by adolescent behaviors or characteristics, and ethnographic or other qualitative methods should be accompanied by greater specificity in terminology to alert researchers to the various phenomena being studied (i.e., “reputational crowd,” “interactional crowd,” “behavioral crowd,” “affiliation crowd”). Additionally, studies comparing the various self-identification approaches and peer ratings are needed, along with reliability studies of peer ratings. More attention to specific methodology to determine crowd membership and its stability will aid the design of theoretical models of adolescent crowds and contribute to developmental outcome research

Associations of Parental and Peer Characteristics with Adolescents’ Social Dominance Orientation

Studies with adults of social dominance orientation (SDO), a preference for inequality among social groups, have found correlations with various prejudices and support for discriminatory practices. This study explores the construct among adolescents at an age when they are beginning to recognize the social groups in their environment, particularly adolescent crowds. The relationship of SDO and perceptions of parents’ responsiveness and demandingness were also investigated. Subjects were in grades 9–12 (N = 516, 53% female, 96% White). Mother’s and father’s responsiveness significantly predicted adolescent’s SDO scores, with greater perceived responsiveness associated with lower SDO. To analyze the multiple crowd memberships of the 76% belonging to more than one crowd, two-step cluster analysis was used to identify patterns, resulting in 8 clusters of distinct, heterogeneous composition. SDO differed significantly among males in different clusters, but not females. The importance of membership was positively associated with SDO among high-status crowds and negatively associated with SDO among the academic and normal crowds. The findings have implications for prejudices that may be developing in adolescence and indicate a need for further research into the social context of SDO and its development

Social and emotional components of book reading between caregivers and their toddlers in a high-risk sample

In this collective case study of caregiver behaviors with their toddlers, two-minute videotaped reading interactions were analyzed using a constant comparative method. Twenty-four caregiver—toddler dyads from a high-risk sample of children prenatally exposed to cocaine were selected from a larger sample because they represented the extremes of expressive language scores on the Reynell Expressive Language Quotient at 36 months, one year after the reading interactions. Caregivers in the high-scoring group shared control of the book and discourse, were ‘in tune’ with the child’s needs and abilities, and answered their own questions to the children. This was in contrast to the behaviors of caregivers of the low-scoring children, who appeared unaware of the child’s developmental needs in the interaction, particularly in their ability to respond to the questions posed. Implications of the results for future research on caregiver reading with young children are discussed

Profiles of Temperament and Perfectionism in High Ability College Students

Different physical, mental, and motivational outcomes for perfectionistic strivings and perfectionistic concerns indicate that individuals have different experiences of perfectionism. Although research has focused on parenting practices as a factor related to these differences, little research has examined the impact of temperamental differences on perfectionism. In the current study, 434 high ability undergraduate students completed perfectionism, adult temperament, and personality measures. Latent class analysis that examined the patterns among the relationships between self-oriented perfectionism, socially prescribed perfectionism, and four dimensions of adult temperament (negative affect, effortful control, extraversion, orienting sensitivity) revealed three distinct subgroups. Although the largest subgroup demonstrated patterns consistent with prior research on perfectionism (e.g., perfectionism associated with negative affect), two other subgroups revealed separate patterns that were inconsistent with prior research (e.g., one subgroup had negative relationships between negative affect and both types of perfectionism). Our results demonstrate that temperament may play an important role in explaining the heterogeneity among perfectionists

The effects of processing and mastication on almond lipid bioaccessibility using novel methods of in vitro digestion modelling and micro-structural analysis

A number of studies have demonstrated that consuming almonds increases satiety but does not result in weight gain, despite their high energy and lipid content. To understand the mechanism of almond digestion, in the present study, we investigated the bioaccessibility of lipids from masticated almonds during in vitro simulated human digestion, and determined the associated changes in cell-wall composition and cellular microstructure. The influence of processing on lipid release was assessed by using natural raw almonds (NA) and roasted almonds (RA). Masticated samples from four healthy adults (two females, two males) were exposed to a dynamic gastric model of digestion followed by simulated duodenal digestion. Between 7·8 and 11·1 % of the total lipid was released as a result of mastication, with no significant differences between the NA and RA samples. Significant digestion occurred during the in vitro gastric phase (16·4 and 15·9 %) and the in vitro duodenal phase (32·2 and 32·7 %) for the NA and RA samples, respectively. Roasting produced a smaller average particle size distribution post-mastication; however, this was not significant in terms of lipid release. Light microscopy showed major changes that occurred in the distribution of lipid in all cells after the roasting process. Further changes were observed in the surface cells of almond fragments and in fractured cells after exposure to the duodenal environment. Almond cell walls prevented lipid release from intact cells, providing a mechanism for incomplete nutrient absorption in the gut. The composition of almond cell walls was not affected by processing or simulated digestion

Bioengineering commensal bacteria-derived outer membrane vesicles for delivery of biologics to the gastrointestinal and respiratory tract.

Gram-negative bacteria naturally produce and secrete nanosized outer membrane vesicles (OMVs). In the human gastrointestinal tract, OMVs produced by commensal Gram-negative bacteria can mediate interactions amongst host cells (including between epithelial cells and immune cells) and maintain microbial homeostasis. This OMV-mediated pathway for host-microbe interactions could be exploited to deliver biologically active proteins to the body. To test this we engineered the Gram-negative bacterium Bacteroides thetaiotaomicron (Bt), a prominent member of the intestinal microbiota of all animals, to incorporate bacteria-, virus- and human-derived proteins into its OMVs. We then used the engineered Bt OMVs to deliver these proteins to the respiratory and gastrointestinal (GI)-tract to protect against infection, tissue inflammation and injury. Our findings demonstrate the ability to express and package both Salmonella enterica ser. Typhimurium-derived vaccine antigens and influenza A virus (IAV)-derived vaccine antigens within or on the outer membrane of Bt OMVs. These antigens were in a form capable of eliciting antigen-specific immune and antibody responses in both mucosal tissues and systemically. Furthermore, immunisation with OMVs containing the core stalk region of the IAV H5 hemagglutinin from an H5N1 strain induced heterotypic protection in mice to a 10-fold lethal dose of an unrelated subtype (H1N1) of IAV. We also showed that OMVs could express the human therapeutic protein, keratinocyte growth factor-2 (KGF-2), in a stable form that, when delivered orally, reduced disease severity and promoted intestinal epithelial repair and recovery in animals administered colitis-inducing dextran sodium sulfate. Collectively, our data demonstrates the utility and effectiveness of using Bt OMVs as a mucosal biologics and drug delivery platform technology

Bioengineering commensal bacteria-derived outer membrane vesicles for delivery of biologics to the gastrointestinal and respiratory tract

Gram-negative bacteria naturally produce and secrete nanosized outer membrane vesicles (OMVs). In the human gastrointestinal tract, OMVs produced by commensal Gram-negative bacteria can mediate interactions amongst host cells (including between epithelial cells and immune cells) and maintain microbial homeostasis. This OMV-mediated pathway for host-microbe interactions could be exploited to deliver biologically active proteins to the body. To test this we engineered the Gram-negative bacterium Bacteroides thetaiotaomicron (Bt), a prominent member of the intestinal microbiota of all animals, to incorporate bacteria-, virus- and human-derived proteins into its OMVs. We then used the engineered Bt OMVs to deliver these proteins to the respiratory and gastrointestinal (GI)-tract to protect against infection, tissue inflammation and injury. Our findings demonstrate the ability to express and package both Salmonella enterica ser. Typhimurium-derived vaccine antigens and influenza A virus (IAV)-derived vaccine antigens within or on the outer membrane of Bt OMVs. These antigens were in a form capable of eliciting antigen-specific immune and antibody responses in both mucosal tissues and systemically. Furthermore, immunisation with OMVs containing the core stalk region of the IAV H5 hemagglutinin from an H5N1 strain induced heterotypic protection in mice to a 10-fold lethal dose of an unrelated subtype (H1N1) of IAV. We also showed that OMVs could express the human therapeutic protein, keratinocyte growth factor-2 (KGF-2), in a stable form that, when delivered orally, reduced disease severity and promoted intestinal epithelial repair and recovery in animals administered colitis-inducing dextran sodium sulfate. Collectively, our data demonstrates the utility and effectiveness of using Bt OMVs as a mucosal biologics and drug delivery platform technology

Differential sensing with arrays of de novo designed peptide assemblies

Differential sensing attempts to mimic the mammalian senses of smell and taste to identify analytes and complex mixtures. In place of hundreds of complex, membrane-bound G-protein coupled receptors, differential sensors employ arrays of small molecules. Here we show that arrays of computationally designed de novo peptides provide alternative synthetic receptors for differential sensing. We use self-assembling α-helical barrels (αHBs) with central channels that can be altered predictably to vary their sizes, shapes and chemistries. The channels accommodate environment-sensitive dyes that fluoresce upon binding. Challenging arrays of dye-loaded barrels with analytes causes differential fluorophore displacement. The resulting fluorimetric fingerprints are used to train machine-learning models that relate the patterns to the analytes. We show that this system discriminates between a range of biomolecules, drink, and diagnostically relevant biological samples. As αHBs are robust and chemically diverse, the system has potential to sense many analytes in various settings

Why alternative teenagers self-harm: exploring the link between non-suicidal self-injury, attempted suicide and adolescent identity

Background: The term ‘self-harm’ encompasses both attempted suicide and non-suicidal self-injury (NSSI). Specific adolescent subpopulations such as ethnic or sexual minorities, and more controversially, those who identify as ‘Alternative’ (Goth, Emo) have been proposed as being more likely to self-harm, while other groups such as ‘Jocks’ are linked with protective coping behaviours (for example exercise). NSSI has autonomic (it reduces negative emotions) and social (it communicates distress or facilitates group ‘bonding’) functions. This study explores the links between such aspects of self-harm, primarily NSSI, and youth subculture.<p></p> Methods: An anonymous survey was carried out of 452 15 year old German school students. Measures included: identification with different youth cultures, i.e. Alternative (Goth, Emo, Punk), Nerd (academic) or Jock (athletic); social background, e.g. socioeconomic status; and experience of victimisation. Self-harm (suicide and NSSI) was assessed using Self-harm Behavior Questionnaire and the Functional Assessment of Self-Mutilation (FASM).<p></p> Results: An “Alternative” identity was directly (r ≈ 0.3) and a “Jock” identity inversely (r ≈ -0.1) correlated with self-harm. “Alternative” teenagers self-injured more frequently (NSSI 45.5% vs. 18.8%), repeatedly self-injured, and were 4–8 times more likely to attempt suicide (even after adjusting for social background) than their non-Alternative peers. They were also more likely to self-injure for autonomic, communicative and social reasons than other adolescents.<p></p> Conclusions: About half of ‘Alternative’ adolescents’ self-injure, primarily to regulate emotions and communicate distress. However, a minority self-injure to reinforce their group identity, i.e. ‘To feel more a part of a group’

Genomic Profiling of Childhood Tumor Patient-Derived Xenograft Models to Enable Rational Clinical Trial Design.

Accelerating cures for children with cancer remains an immediate challenge as a result of extensive oncogenic heterogeneity between and within histologies, distinct molecular mechanisms evolving between diagnosis and relapsed disease, and limited therapeutic options. To systematically prioritize and rationally test novel agents in preclinical murine models, researchers within the Pediatric Preclinical Testing Consortium are continuously developing patient-derived xenografts (PDXs)-many of which are refractory to current standard-of-care treatments-from high-risk childhood cancers. Here, we genomically characterize 261 PDX models from 37 unique pediatric cancers; demonstrate faithful recapitulation of histologies and subtypes; and refine our understanding of relapsed disease. In addition, we use expression signatures to classify tumors for TP53 and NF1 pathway inactivation. We anticipate that these data will serve as a resource for pediatric oncology drug development and will guide rational clinical trial design for children with cancer