Neighborhood disadvantage and parenting predict longitudinal clustering of uncinate fasciculus microstructural integrity and clinical symptomatology in adolescents.

Parenting behaviors and neighborhood environment influence the development of adolescents' brains and behaviors. Simultaneous trajectories of brain and behavior, however, are understudied, especially in these environmental contexts. In this four-wave study spanning 9-18 years of age (N=224 at baseline, N=138 at final assessment) we used longitudinal k-means clustering to identify clusters of participants with distinct trajectories of uncinate fasciculus (UF) fractional anisotropy (FA) and anxiety symptoms; we examined behavioral outcomes and identified environmental factors that predicted cluster membership. We identified three clusters of participants: 1) high UF FA and low symptoms ("low-risk"); 2) low UF FA and high symptoms ("high-risk"); and 3) low UF FA and low symptoms ("resilient"). Adolescents in disadvantaged neighborhoods were more likely to be in the resilient than high-risk cluster if they also experienced maternal warmth. Thus, neighborhood disadvantage may confer neural risk for psychopathology that can be buffered by maternal warmth, highlighting the importance of considering multiple environmental influences in understanding emotional and neural development in youth.

The acute effect of a commercial bite-aligning mouthpiece on strength and power in recreationally trained men.

Because of the relative newness of mouthpieces, there are few investigations into using performance mouthpieces during sport and physical activity to substantiate claims of performance enhancement. The purpose of this study was to investigate the acute effect of a commercially available, noninjury preventive, performance mouthpiece on practical acute performance measures of power and strength. A within-subjects design was used to evaluate 21 (N = 21) recreationally trained college aged males on the performance of a maximum countermovement vertical jump (CMVJ) from a force platform and 1 repetition maximum (1RM) bench press exercise for the following conditions: with mouthpiece (MP) and without mouthpiece (noMP). Rate of force development (RFD) and peak vertical force (PF) were derived from force platform data. Statistical analysis revealed no significant differences between conditions for CMVJ height (p = 0.13), RFD at 200 ms (p = 0.09), PF (p = 0.08), and 1RM bench press (p = 0.45). These data indicate that the use of this particular jaw aligning mouthpiece specifically in an attempt to produce an ergogenic effect on performance is unwarranted.

Haemophilus influenzae type b in respiratory secretions.

Oral and respiratory secretions of 31 children who were healthy or had mild upper respiratory infection, and who had a positive throat culture for Haemophilus influenzae type b, were cultured to determine which secretions contain this organism and how long it can be recovered from fomites. Rhinorrhea was present in 11 of 31 (34%) children and nasal mucus was positive for H. influenzae type b in 10 (91%). In 5 of these children the concentration of H. influenzae type b in nasal mucus was 10(4) to 10(7) colony-forming units/ml3. H. influenzae type b in nasal mucus applied to fomites were recovered for 12 hours. Cultures of saliva and cough secretions compared with nasal mucus were less often positive (3 of 31, P less than 0.001; 3 of 25, P less than 0.001, respectively) and contained fewer H. influenzae type b (5 and 15 colony-forming units, respectively). H. influenzae type b was recovered from the hand of 2 of 27 (7%) children; both children had positive cultures of saliva. These data indicate that H. influenzae type b can be found in oral and respiratory secretions of pharyngeal carriers and can contaminate children's hands. Nasal mucus was the most consistently positive secretion and contained the largest number of bacteria. Careful management of nasal mucus secretions is warranted in settings where transmission could occur to susceptible children.