School-related stress among sixth-grade students - associations with academic buoyancy and temperament

The present study examined to what extent sixth-grade students’ academic buoyancy and temperament contributed to their school-related stress. A total of 845 students rated their school-related stress at the beginning and end of the school year and their academic buoyancy at the beginning of the year. Parents rated students’ effortful control and negative affectivity. The results showed that high academic buoyancy, high effortful control, and low negative affectivity at the beginning of the school year were related to lower school-related stress at the end of the school year, after controlling for gender, GPA, and previous level of stress. Effortful control and negative affectivity had no significant interaction effect with academic buoyancy on students’ school-related stress. The findings of the study suggest that interventions aiming at supporting students’ academic buoyancy may also decrease their feelings of school stress. In particular, students with high negative affectivity or low effortful control may need training in stress management skills

Suicides in Aboriginal and non-Aboriginal people following hospital admission for suicidal ideation and self-harm: A retrospective cohort data linkage study from the Northern Territory

Purpose: This study aimed to explore risk factors for suicide in Aboriginal and non-Aboriginal people following hospital admission for suicidal ideation and self-harm in the Northern Territory, Australia to help clarify opportunities for improved care and intervention for these population groups. Methods: Individuals with at least one hospital admission involving suicidal ideation and/or self-harm between 1 July 2001 and 31 December 2013 were retrospectively recruited and followed up using linked mortality records to 31 December 2014. Survival analyses stratified by Indigenous status identified socio-demographic and clinical characteristics from index hospital admissions associated with suicide. Results: Just over half of the 4391 cohort members identified as Aboriginal (n = 2304; 52.4%). By 2014, 281 deaths were observed comprising 68 suicides, representing a 2.6% and 2.0% probability of suicide for Aboriginal and non-Aboriginal people, respectively. After adjusting for other characteristics, a higher risk of suicide was associated with male sex (Aboriginal adjusted hazard ratio: 4.14; 95% confidence interval: [1.76, 9.75]; non-Aboriginal adjusted hazard ratio: 5.96; 95% confidence interval: [1.98, 17.88]) and repeat hospital admissions involving self-harm (Aboriginal adjusted hazard ratio: 1.37; 95% confidence interval: [1.21, 1.55]; non-Aboriginal adjusted hazard ratio: 1.29; 95% confidence interval: [1.10, 1.51]). Severe mental disorders were associated with a four times higher risk of suicide (adjusted hazard ratio: 4.23; 95% confidence interval: [1.93, 9.27]) in Aboriginal people only. Conclusion: The findings highlight non-clinical risk factors for suicide that suggest the need for comprehensive psychosocial assessment tailored to Aboriginal and non-Aboriginal people hospitalised with suicidal ideation or self-harm. Implementing appropriate management and aftercare within a broader public health framework is needed to support recovery and reduce long-term suicide risk in the community, especially for Aboriginal people and males

Dynamic relaxation of the elastic properties of hard carbon films

The effect of enhanced atomic mobility on the growth of hard carbon films was examined. Tetrahedrally bonded amorphous carbon films were deposited by condensing energetic carbon ions using an arc-discharge deposition method. The deposition temperature varied between 50 and 400 °C. The dependence of elastic properties on deposition temperature was examined by determining the frequency-dependent propagation velocity of ultrasonic surface acoustic waves induced by a laser. A remarkable decrease in elastic coefficient was revealed above the deposition temperature of 300 °C and complete relaxation was obtained at 400 °C. This observation was analyzed by using a simple model which was in turn supported by molecular dynamics simulations. The relaxation turns out to be a thermally activated, dynamic process with an activation energy of 0.57 eV. Possible relaxation mechanisms associated with the migration of atoms or defects on a growing surface are discussed.Peer reviewe

Excimer laser surface modification: Process and properties

Surface modification can improve materials for structural, tribological, and corrosion applications. Excimer laser light has been shown to provide a rapid means of modifying surfaces through heat treating, surface zone refining, and mixing. Laser pulses at modest power levels can easily melt the surfaces of many materials. Mixing within the molten layer or with the gas ambient may occur, if thermodynamically allowed, followed by rapid solidification. The high temperatures allow the system to overcome kinetic barriers found in some ion mixing experiments. Alternatively, surface zone refinement may result from repeated melting-solidification cycles. Ultraviolet laser light couples energy efficiently to the surface of metallic and ceramic materials. The nature of the modification that follows depends on the properties of the surface and substrate materials. Alloying from both gas and predeposited layer sources has been observed in metals, semiconductors, and ceramics as has surface enrichment of Cr by zone refinement of stainless steel. Rapid solidification after melting often results in the formation of nonequilibrium phases, including amorphous materials. Improved surface properties, including tribology and corrosion resistance, are observed in these materials

Experimental PVC Material Challenge in Subjects with Occupational PVC Exposure

BACKGROUND: Polyvinyl chloride (PVC) materials have been linked to asthma in several epidemiologic studies, but the possible causal factors remain unknown. PARTICIPANTS: We challenged 10 subjects experimentally to degraded PVC products under controlled conditions. All of the subjects had previously experienced respiratory symptoms suspected to be caused by this kind of exposure in their work place. Five subjects had doctor-diagnosed asthma. METHODS: The subjects were exposed to degraded PVC material in an exposure chamber; a challenge with ceramic tile was used as the control test. We followed exhaled nitric oxide, nasal NO, lung functions, cytokines [tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-6, and IL-12] and NO in nasal lavage fluid (NAL) during and after the exposures. We also measured 2-ethylhexanol in exhaled breath samples and NAL. RESULTS: On the morning after the PVC exposure, subjects reported respiratory tract symptoms significantly more often than they did after the control test (50% vs. 0%, respectively; p = 0.029; n = 10). We did not detect any changes in lung functions or levels of exhaled NO, nasal NO, or NO in NAL after PVC challenge compared with the control test. Cytokine levels increased after both exposures, with no statistically significant difference between situations. All of the exhaled breath samples collected during the PVC exposure contained 2-ethylhexanol. CONCLUSIONS: PVC flooring challenge can evoke respiratory tract symptoms in exposed subjects. Our results do not support the hypothesis that PVC materials themselves evoke immediate asthmatic reactions. The chamber test used is well suited to this type of exposure study

Energetics and structure of grain boundary triple junctions in graphene

© 2017 The Author(s). Grain boundary triple junctions are a key structural element in polycrystalline materials. They are involved in the formation of microstructures and can influence the mechanical and electronic properties of materials. In this work we study the structure and energetics of triple junctions in graphene using a multiscale modelling approach based on combining the phase field crystal approach with classical molecular dynamics simulations and quantum-mechanical density functional theory calculations. We focus on the atomic structure and formation energy of the triple junctions as a function of the misorientation between the adjacent grains. We find that the triple junctions in graphene consist mostly of five-fold and seven-fold carbon rings. Most importantly, in addition to positive triple junction formation energies we also find a significant number of orientations for which the formation energy is negative

Microfluidic assembly of multistage porous silicon-lipid vesicles for controlled drug release

A reliable microfluidic platform for the generation of stable and monodisperse multistage drug delivery systems is reported. A glass-capillary flow-focusing droplet generation device was used to encapsulate thermally hydrocarbonized porous silicon (PSi) microparticles into the aqueous cores of double emulsion drops, yielding the formation of a multistage PSi–lipid vesicle. This composite system enables a large loading capacity for hydrophobic drugs.Peer reviewe