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This study used data from 12 cultural groups in 9 countries (China, Colombia, Italy, Jordan, Kenya, Philippines, Sweden, Thailand, and United States; N = 1,315) to investigate bidirectional associations between parental warmth and control, and child externalizing and internalizing behaviors. In addition, the extent to which these associations held across mothers and fathers and across cultures with differing normative levels of parent warmth and control were examined. Mothers, fathers, and children completed measures when children were ages 8 to 13. Multiple-group autoregressive cross-lagged structural equation models revealed that evocative child-driven effects of externalizing and internalizing behavior on warmth and control are ubiquitous across development, cultures, mothers, and fathers. Results also reveal that parenting effects on child externalizing and internalizing behaviors, though rarer than child effects, extend into adolescence when examined separately in mothers and fathers. Father-based parent effects were more frequent than mother effects. Most parent- and child-driven effects appear to emerge consistently across cultures. The rare culture-specific parenting effects suggested that occasionally the effects of parenting behaviors that run counter to cultural norms may be delayed in rendering their protective effect against deleterious child outcomes.
We consider peeling of an elastic sheet away from an elastic substrate through propagation of a fluid-filled crack along the interface between the two. The peeling is driven by a bending moment applied to the sheet and is resisted by viscous flow towards the crack tip and by the toughness of any bonding between the sheet and the substrate. Travelling-wave solutions are determined using lubrication theory coupled to the full equations of elasticity and fracture. The propagation speed
is the sheet’s thickness,
its plane-strain modulus,
the fluid viscosity,
the applied bending moment and
the sheet’s curvature due to bending; and the prefactor depends on the dimensionless toughness. If the toughness is small then there is a region of dry shear failure ahead of the fluid-filled region. The expressions for the propagation speed have been used to derive new similarity solutions for the spread of an axisymmetric fluid-filled blister in a variety of regimes: constant-flux injection resisted by elastohydrodynamics in the tip leads to spread proportional to
for peeling-by-bending, gravitational spreading and peeling-by-pulling, respectively.
Incorporation of metallic nanoparticles (NPs) in polymer matrix has been used to enhance and control dissolution and release of drugs, for targeted drug delivery, as antimicrobial agents, localized heat sources, and for unique optoelectronic applications. Gold NPs in particular exhibit a plasmonic response that has been utilized for photothermal energy conversion. Because plasmonic nanoparticles typically exhibit a plasmon resonance frequency similar to the visible light spectrum, they present as good candidates for direct photothermal conversion with enhanced solar thermal efficiency in these wavelengths. In our work, we have incorporated ∼3-nm-diameter colloidal gold (Auc) NPs into electrospun polyethylene glycol (PEG) fibers to utilize the nanoparticle plasmonic response for localized heating and melting of the polymer to release medical treatment. Auc and Auc in PEG (PEG+Auc) both exhibited a minimum reflectivity at 522 nm or approximately green wavelengths of light under ultraviolet-visible (UV-Vis) spectroscopy. PEG+Auc ES fibers revealed a blue shift in minimum reflectivity at 504 nm. UV-Vis spectra were used to calculate the theoretical efficiency enhancement of PEG+Auc versus PEG alone, finding an approximate increase of 10 % under broad spectrum white light interrogation, and ∼14 % when illuminated with green light. Auc enhanced polymers were ES directly onto resistance temperature detectors and interrogated with green laser light so that temperature change could be recorded. Results showed a maximum increase of 8.9 °C. To further understand how gold nanomaterials effect the complex optical properties of our materials, spectroscopic ellipsometry was used. Using spectroscopic ellipsometry and modeling with CompleteEASE® software, the complex optical constants of our materials were determined. The complex optical constant n (index of refraction) provided us with optical density properties related to light wavelength divided by velocity, and k (extinction coefficient) was used to show the absorptive properties of the materials.
Using multilevel models, we examined mother-, father-, and child-reported (N = 1,336 families) externalizing behavior problem trajectories from age 7 to 14 in nine countries (China, Colombia, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States). The intercept and slope of children's externalizing behavior trajectories varied both across individuals within culture and across cultures, and the variance was larger at the individual level than at the culture level. Mothers’ and children's endorsement of aggression as well as mothers’ authoritarian attitudes predicted higher age 8 intercepts of child externalizing behaviors. Furthermore, prediction from individual-level endorsement of aggression and authoritarian attitudes to more child externalizing behaviors was augmented by prediction from cultural-level endorsement of aggression and authoritarian attitudes, respectively. Cultures in which father-reported endorsement of aggression was higher and both mother- and father-reported authoritarian attitudes were higher also reported more child externalizing behavior problems at age 8. Among fathers, greater attributions regarding uncontrollable success in caregiving situations were associated with steeper declines in externalizing over time. Understanding cultural-level as well as individual-level correlates of children's externalizing behavior offers potential insights into prevention and intervention efforts that can be more effectively targeted at individual children and parents as well as targeted at changing cultural norms that increase the risk of children's and adolescents’ externalizing behavior.
Melt electrospinning is a facile fabrication technique that can be utilized in the creation of microfibers without the use of solvent and with good control over feature placement. The available thermal energy of the melt electrospinning technique is often only utilized in the formation of the polymer melt but can also be used to thermodynamically drive chemical reactions. In this study, hybrid perovskite microcrystallites are synthesized in the polymer melt and electrospun to form composite microfibers. Unique hybrid perovskite microstructures were studied, elucidating mechanisms of formation at work in the polymer melt.
Invasive rodents detrimentally affect native bird species on many islands worldwide, and rodent eradication is a useful tool to safeguard endemic and threatened species. However, especially on tropical islands, rodent eradications can fail for various reasons, and it is unclear whether the temporary reduction of a rodent population during an unsuccessful eradication operation has beneficial effects on native birds. Here we examine the response of four endemic land bird species on subtropical Henderson Island in the Pitcairn Island Group, South Pacific Ocean, following an unsuccessful rodent eradication in 2011. We conducted point counts at 25 sampling locations in 14 survey periods between 2011 and 2015, and modelled the abundance trends of all species using binomial mixture models accounting for observer and environmental variation in detection probability. Henderson Reed Warbler Acrocephalus taiti more than doubled in abundance (2015 population estimate: 7,194-28,776), and Henderson Fruit Dove Ptilinopus insularis increased slightly between 2011 and 2015 (2015 population estimate: 4,476–10,072), while we detected no change in abundance of the Henderson Lorikeet Vini stepheni (2015 population estimate: 554–3014). Henderson Crake Zapornia atra increased to pre-eradication levels following anticipated mortality during the operation (2015 population estimate: 4,960–20,783). A temporary reduction of rat predation pressure and rat competition for fruit may have benefitted the reed warbler and the fruit dove, respectively. However, a long drought may have naturally suppressed bird populations prior to the rat eradication operation in 2011, potentially confounding the effects of temporary rat reduction and natural recovery. We therefore cannot unequivocally ascribe the population recovery to the temporary reduction of the rat population. We encourage robust monitoring of island biodiversity both before and after any management operation to better understand responses of endemic species to failed or successful operations.
Bacterial cultures exposed to iron-doped apatite nanoparticles (IDANPs) prior to the introduction of antagonistic viruses experience up to 2.3 times the bacterial destruction observed in control cultures. Maximum antibacterial activity of these bacteria-specific viruses, or phage, occurs after bacterial cultures have been exposed to IDANPs for 1 hr prior to phage introduction, demonstrating that IDANP-assisted phage therapy would not be straight forward, but would instead require controlled time release of IDANPs and phage. These findings motivated the design of an electrospun nanofiber mesh treatment delivery system that allows burst release of IDANPs, followed by slow, consistent release of phage for treatment of topical bacterial infections. IDANPs resemble hydroxyapatite, a biocompatible mineral analogous to the inorganic constituent of mammalian bone, which has been approved by the Food and Drug Administration for many biomedical purposes. The composite nanofiber mesh was designed for IDANP-assisted phage therapy treatment of topical wounds and consists of a superficial, rapid release layer of polyethylene oxide (PEO) fibers doped with IDANPs, followed by inner, coaxial polycaprolactone / polyethylene glycol (PCL/PEG) blended polymer fiber layer for slower phage delivery. Our investigations have established that IDANP-doped PEO fibers are effective vehicles for dissemination of IDANPs for bacterial exposure and resultant increased bacterial death by phage. In this work, slower delivery of the phage behind IDANPs was accomplished using coaxial, electrospun fibers composed of PCL/PEG polymer blend.
Using data from 1,177 families in eight countries (Colombia, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States), we tested a conceptual model of direct effects of childhood family adversity on subsequent externalizing behaviors as well as indirect effects through psychological mediators. When children were 9 years old, mothers and fathers reported on financial difficulties and their use of corporal punishment, and children reported perceptions of their parents’ rejection. When children were 10 years old, they completed a computerized battery of tasks assessing reward sensitivity and impulse control and responded to questions about hypothetical social provocations to assess their hostile attributions and proclivity for aggressive responding. When children were 12 years old, they reported on their externalizing behavior. Multigroup structural equation models revealed that across all eight countries, childhood family adversity had direct effects on externalizing behaviors 3 years later, and childhood family adversity had indirect effects on externalizing behavior through psychological mediators. The findings suggest ways in which family-level adversity poses risk for children's subsequent development of problems at psychological and behavioral levels, situated within diverse cultural contexts.
Hybrid organic-inorganic perovskites (HOIPs) have been previously compounded with hydrophobic polymers in order to improve the resilience of HOIPs in humid environments. In this study HOIP particles were synthesized and dispersed into a polymer solution. The weight loading of the HOIP phase in the composite was increased until an abrupt change in the electrical conduction was observed indicating a percolation threshold was approached. Additionally, the CH3NH3PbI3/ polystyrene composite media was characterized to assess morphology and the effect it has on the observed electrical properties.
Composite nanostructured foams consisting of a metallic shell deposited on a polymeric core were formed by plating copper via electroless deposition on electrospun polycaprolactone (PCL) fiber mats. The final structure consisted of 1000-nm scale PCL fibers coated with 100s of nm of copper, leading to final core-shell thicknesses on the order of 1000-3000 nm. The resulting open cell, core-shell foams had relative densities between 4 and 15 %. By controlling the composition of the adjuncts in the plating bath, particularly the composition of formaldehyde, the relative thickness of copper coating as the fiber diameter could be controlled. As-spun PCL mats had a nominal compressive modulus on the order of 0.1 MPa; adding a uniform metallic shell increased the modulus up to 2 MPa for sub-10 % relative density foams. A computational materials science analysis using density functional theory was used to explore the effects pre-treatment with Pd may have on the density of nuclei formed during electroless plating.
According to the Centers for Disease Control (CDC) and prevention, at least 2 million people in the United States become infected with antibiotic-resistant bacteria, and at least 23,000 people die each year as a direct result of those infections. One alternative to traditional antibiotics is bacteriophage (phage) therapy. Phage therapy utilizes bacteria-specific viruses to infect and kill bacteria cells. The specificity of these viruses is beneficial in that phage used for therapeutic purposes do not harm the human microbiota, nor do phage infect eukaryotic cells. It has been discovered that iron-doped apatite nanoparticles (IDANPs) significantly enhance phage killing of bacteria cells. The biocompatibility of apatite, coupled with its effectiveness as an adjuvant to enhance an alternative antibiotic therapy, makes it of interest for medical applications. Previously, researchers have encased phage in a microfluidic channel in coaxially electrospun fibers, allowing phage to remain viable after several weeks storage at 4 °C. Here, we have constructed a polymer fiber layer using electrospinning (ES) for delivery of IDANP adjuvants to compliment phage treatment delivery fibers. The IDANP delivery layer constructed is composed of polyethylene oxide (PEO) doped with the nanoparticles. When compared to media-only and IDANP-only controls, results show IDANPs delivered through a PEO fiber mesh remain effective at enhancement of phage infectivity.
Control of fire was a hallmark of developing human cognition and an essential technology for the colonisation of cooler latitudes. In Europe, the earliest evidence comes from recent work at the site of Cueva Negra del Estrecho del Río Quípar in south-eastern Spain. Charred and calcined bone and thermally altered chert were recovered from a deep, 0.8-million-year-old sedimentary deposit. A combination of analyses indicated that these had been heated to 400–600°C, compatible with burning. Inspection of the sediment and hydroxyapatite also suggests combustion and degradation of the bone. The results provide new insight into Early Palaeolithic use of fire and its significance for human evolution.
Introduction: Closed reduction of distal radius fractures (CRDRF) is a commonly performed emergency department (ED) procedure. The use of Point-of-care ultrasound (POCUS) to diagnose fractures and guide reduction has previously been described. The primary objective for this study was to determine if the addition of PoCUS to CRDRF changed the perception of successful initial reduction. This was measured by the rate of further reduction attempts based on POCUS following the initial clinical determination of achievement of best possible reduction. Methods: We performed a multicenter prospective cohort study, using a convenience sample of adult ED patients presenting with a distal radius fracture to 5 Canadian EDs. All study physicians underwent standardized PoCUS training for fractures. Standard clinically guided best possible fracture reduction was initially performed. PoCUS was then used to assess the reduction adequacy. Repeat reduction was performed if deemed indicated. A post-reduction radiograph was then performed. Clinician impression of reduction adequacy was scored on a 5 point Likert scale following the initial clinically guided reduction, and following each POCUS scan and the post-reduction radiograph. Results: There were 131 patients with 132 distal radius fractures. Twelve cases were excluded prior to analysis. There was no significant difference in the assessment scores for reduction success by PoCUS vs. clinical assessment (Median scores 4 vs.4; p=0.370;) or in the odds ratio of successful reduction (0.89; 95% CI 0.46 to 1.72; p=0.87). Significantly fewer cases fell in the uncertain category with POCUS than with clinical assessment (12 vs 2; p=0.008). Repeat reduction was performed in 49 patients (41.2%). In this group, the odds ratio for adequate reduction assessment post-PoCUS to pre-PoCUS was 12.5 (95% CI 3.42 to 45.7; p<0.0001). There was no significant difference in the assessment of reduction by PoCUS vs. radiograph. Conclusion: PoCUS guided fracture reduction leads to repeat reduction attempts in approximately 40% of cases, and enhances certainty regarding reduction adequacy when clinical assessment is unclear.
A new organometallic halide perovskite (OHP) synthesis method, whereby a polymer melt is used to thermodynamically drive the reaction that forms OHP crystallites, is demonstrated. The synthesis method allows for the facile encapsulation of moisture-sensitive OHP without the loss of simplicity during fabrication, which makes OHP materials so attractive for the photovoltaic industry. Degradation of OHP crystallites embedded in a polystyrene matrix was studied using UV-Vis absorbance over a period of several days. The OHP crystallites degrade as a result of the reversible nature of the reaction that forms the crystallites. After the reversion to precursors (PbI2 and CH3NH3I) the CH3NH3I irreversibly degrades  allowing the degradation to be tracked via optical interrogation. Additionally, surface morphology and elemental analysis of fabricated samples was carried out using SEM/EDS techniques.
This study advances understanding of predictors of child abuse and neglect at multiple levels of influence. Mothers, fathers, and children (N = 1,418 families, M age of children = 8.29 years) were interviewed annually in three waves in 13 cultural groups in nine countries (China, Colombia, Italy, Jordan, Kenya, Philippines, Sweden, Thailand, and the United States). Multilevel models were estimated to examine predictors of (a) within-family differences across the three time points, (b) between-family within-culture differences, and (c) between-cultural group differences in mothers' and fathers' reports of corporal punishment and children's reports of their parents' neglect. These analyses addressed to what extent mothers' and fathers' use of corporal punishment and children's perceptions of their parents' neglect were predicted by parents' belief in the necessity of using corporal punishment, parents' perception of the normativeness of corporal punishment in their community, parents' progressive parenting attitudes, parents' endorsement of aggression, parents' education, children's externalizing problems, and children's internalizing problems at each of the three levels. Individual-level predictors (especially child externalizing behaviors) as well as cultural-level predictors (especially normativeness of corporal punishment in the community) predicted corporal punishment and neglect. Findings are framed in an international context that considers how abuse and neglect are defined by the global community and how countries have attempted to prevent abuse and neglect.
Better performance due to repeated testing can bias long-term trajectories of cognitive aging and correlates of change. We examined whether retest effects differ as a function of individual differences pertinent to cognitive aging: race/ethnicity, age, sex, language, years of education, literacy, and dementia risk factors including apolipoprotein E ε4 status, baseline cognitive performance, and cardiovascular risk. We used data from the Washington Heights-Inwood Columbia Aging Project, a community-based cohort of older adults (n=4073). We modeled cognitive change and retest effects in summary factors for general cognitive performance, memory, executive functioning, and language using multilevel models. Retest effects were parameterized in two ways, as improvement between the first and subsequent testings, and as the square root of the number of prior testings. We evaluated whether the retest effect differed by individual characteristics. The mean retest effect for general cognitive performance was 0.60 standard deviations (95% confidence interval [0.46, 0.74]), and was similar for memory, executive functioning, and language. Retest effects were greater for participants in the lowest quartile of cognitive performance (many of whom met criteria for dementia based on a study algorithm), consistent with regression to the mean. Retest did not differ by other characteristics. Retest effects are large in this community-based sample, but do not vary by demographic or dementia-related characteristics. Differential retest effects may not limit the generalizability of inferences across different groups in longitudinal research. (JINS, 2015, 21, 506–518)