Similar to adults with posttraumatic stress disorder, children with early life adversity show bias in memory for negative emotional stimuli. However, it is not well understood how childhood adversity impacts mechanisms underlying emotional memory. N = 56 children (8–14 years, 48% female) reported on adverse experiences including potentially traumatic events and underwent fMRI while attending to emotionally pleasant, neutral, or negative images. Post-scan, participants completed a cued recall test to assess memory for these images. Emotional difference-in-memory (DM) scores were computed by subtracting negative or positive from neutral recall performance. All children showed enhancing effects of emotion on recall, with no effect of trauma load. However, children with less trauma showed a larger emotional DM for both positive and negative stimuli when amygdala or anterior hippocampal activity was higher. In contrast, highly trauma-exposed children demonstrated a lower emotional DM with greater amygdala or hippocampal activity. This suggested that alternative neural mechanisms might support emotional enhancement of encoding in children with greater trauma load. Whole-brain analyses revealed that right fusiform activity during encoding positively correlated with both trauma load and successful later recall of positive images. Therefore, highly trauma-exposed children may use alternative, potentially adaptive neural pathways via the ventral visual stream to encode positive emotional events.

Early life adversity (ELA) has been linked with increased arousal responses to threat, including increased amygdala reactivity. Effects of ELA on brain function are well recognized, and emerging evidence suggests that caregivers may influence how environmental stressors impact children’s brain function. We investigated the hypothesis that positive interaction between mother and child can buffer against ELA effects on children’s neural responses to threat, and related symptoms. N = 53 mother–child pairs (children ages 8–14 years) were recruited from an urban population at high risk for violence exposure. Maternal caregiving was measured using the Parenting Questionnaire and in a cooperation challenge task. Children viewed fearful and neutral face stimuli during functional magnetic resonance imaging. Children who experienced greater violence at home showed amygdala sensitization, whereas children experiencing more school and community violence showed amygdala habituation. Sensitization was in turn linked with externalizing symptoms. However, maternal warmth was associated with a normalization of amygdala sensitization in children, and fewer externalizing behaviors prospectively up to 1 year later. Findings suggested that the effects of violence exposure on threat-related neural circuitry depend on trauma context (inside or outside the home) and that primary caregivers can increase resilience.

The study of high-dimensional distributions is of interest in probability theory, statistics, and asymptotic convex geometry, where the object of interest is the uniform distribution on a convex set in high dimensions. The ℓp-spaces and norms are of particular interest in this setting. In this paper we establish a limit theorem for distributions on ℓp-spheres, conditioned on a rare event, in a high-dimensional geometric setting. As part of our proof, we establish a certain large deviation principle that is also relevant to the study of the tail behavior of random projections of ℓp-balls in a high-dimensional Euclidean space.

Poly[sulfur-random-1,3-diisopropenylbenzene (DIB)] copolymers synthesized via inverse vulcanization form electrochemically active polymers used as cathodes for high-energy density Li–S batteries, capable of enhanced capacity retention (1005 mAh/g at 100 cycles) and lifetimes of over 500 cycles. In this prospective, we demonstrate how analytical electron microscopy can be employed as a powerful tool to explore the origins of the enhanced capacity retention. We analyze morphological and compositional features when the copolymers, with DIB contents up to 50% by mass, are blended with carbon nanoparticles. Replacing the elemental sulfur with the copolymers improves the compatibility and interfacial contact between active sulfur compounds and conductive carbons. There also appears to be improvements of the cathode mechanical stability that leads to less cracking but preserving porosity. This compatibilization scheme through stabilized organosulfur copolymers represents an alternative strategy to the nanoscale encapsulation schemes which are often used to improve the cycle life in high-energy density Li–S batteries.

Many important human diseases, such as asthma, have their developmental origins in early life. Respiratory infections in particular may alter the course of asthma and may either protect against or promote the development of this disease. It is likely that the nature of the effects depends on the type and age of infection and is determined by the impact of infection on the immune and respiratory systems. Immunity in early life is plastic and can be moulded by antigen encounter, which may enhance or reinforce the asthmatic phenotype of early life, or induce protective responses. Chlamydial respiratory infections have specific effects and may increase asthma severity in early life by promoting systemic interleukin 13 responses and causing permanent changes in lung structure. Respiratory viral infections, such as those of respiratory syncytial virus and rhinovirus, promote pro-asthmatic responses in early life that contribute to the induction of asthma. By contrast, probiotics or infection or exposure to certain bacteria, such as Streptococcus pneumoniae, may have protective effects in asthma by increasing the numbers and activity of regulatory T cells. Here, we review the impact of infections on the developmental origins of asthma. Understanding these effects may lead to new therapeutic approaches for asthma that either target deleterious infections or utilize beneficial ones.

Bioimpedance spectroscopy (BIS) has been used to track changes in total body water (TBW). Accurate TBW estimations can be influenced by both methodological and biological factors. One methodological variation that contributes to BIS TBW errors is the electrode placement. The purpose of the present study was to compare the reproducibility and validity of fixed-distance electrode placements (5 cm) with the standard single-site electrode placements. Twenty-nine subjects (fifteen men and fourteen women) participated in the reproducibility study, while sixty-nine subjects (thirty-three men and thirty-six women) participated in the validity study. The reproducibility study included two measurements that were taken 24 h apart, while the validity study consisted of a 12-week exercise intervention with measurements taken at weeks 1 and 12. TBW was estimated using BIS and 2H techniques. Reproducibility results indicated that fixed-distance electrodes reduced the day-to-day standard error of the measurement in men (from 1·13 to 0·81 litres) but not in women (0·47 litres). sem values were lower for women than for men, suggesting that BIS TBW estimates are sex dependent. Validity results produced similar accurate findings (mean difference < 0·21 litres). However, fixed-distance electrodes improved delta TBW errors (mean difference improvements>0·04 litres in men, women, and men and women combined). When tracking changes in TBW, fixed-distance electrodes may reduce reproducibility errors and allow for smaller changes to be detected. However, the reduction of reproducibility errors may be greater for men than for women. Therefore, reproducibility calculations should be based on the sex of the sample population.

BaxSr1−xTiO3 (BST, x=0.5 and 0.6) thin films have been deposited onto (100) MgO single crystal substrates by pulsed laser deposition (PLD). The room temperature capacitance and dielectric quality factor (Q=1/tanδ have been measured as a function of electric field (≤ 100 kV/cm) at microwave frequencies (1 to 20 GHz) using silver interdigitated electrodes deposited on top of the BST film. It has been observed that the dielectric constant of the film and its change with electric field are closely related to film phase (amorphous to crystalline phase) and film strain which affects the ionic polarization of the film. Amorphous BST films show high dielectric Q (> 100) with low dielectric constant (∼30–200) and low dielectric tuning (< 1%), presumably due to small ionic polarization. Crystalline films have a higher dielectric constant (∼1000–3000) and a higher dielectric tuning (∼ 65%) but a lower dielectric Q (∼20). As an optimal microstructure of the film for tunable microwave applications, strain-relieved large-grained (∼5000 Å) randomly oriented polycrystalline films were deposited using a thin amorphous buffer layer of BST (∼50 Å). Very large grains (size up to a few microns) were observed in BST films prepared using a thicker amorphous buffer layer (∼500 Å). We will present results on how careful control of microstructure can lead to films with optimal dielectric properties for the tunable microwave devices.