Anxiety and depression symptoms and alcohol use among adolescents - a cross sectional study of Norwegian secondary school students.

BACKGROUND: We investigated the associations between symptoms of anxiety and depression and alcohol drinking behavior among adolescents, by focusing on the importance of symptom load, as well as gender differences. METHODS: Data was derived from a cross-sectional school based survey among adolescents in upper secondary schools in Norway. Among other variables adolescents reported on symptoms of anxiety and depression, time of onset and extent of alcohol use. The sample consisted of 6238 adolescents aged 16-18 years. We estimated prevalence of alcohol drinking behaviors in relation to severity of symptoms of anxiety and depression. RESULTS: Higher levels of depression symptoms were associated with earlier onset of alcohol use, more frequent consumption and intoxications. The associations between anxiety and depression symptoms and early drinking onset were stronger for girls than for boys. Higher levels of anxiety symptoms were only associated with alcohol consumption among girls. CONCLUSIONS: Boys and girls with depressive symptoms and girls with anxiety symptoms are more likely to have unhealthy patterns of alcohol drinking. Preventive strategies at all levels could possibly profit from a common approach to mental health and alcohol use, in particular for girls in mid-adolescence.

Characterization of ozonated vegetable oils by spectroscopic and chromatographic methods.

In this work the effect of ozonation on olive oil, soybean oil, oleic-, linoleic- and linolenic acid was studied. The effects of ozonation time on the oils and acids were analyzed by 1H, 13C NMR. Further, the peroxide- and acid values, the viscosity and the molar mass were determined for pure and ozonated oils. The fatty chains in both ozonated oils showed a gradual decrease of unsaturation with the gradual increase of ozonation time. Reaction products were identified according to Criegee mechanism. The major product in the early stage of the reaction was ozonide. The disappearance of unsaturation and formation of ozonide was almost equal. Ozonation increased the peroxide and acid values for both oils, the increase being higher for soybean oil. After long ozonation times higher molar mass species, as well as low molar mass species were observed. These are interpreted as oligomeric ozonides and cross-ozonides, respectively.

Wet powder processing of sol-gel derived mesoporous silica-hydroxyapatite hybrid powders.

This paper describes a method by which a porous silica coating layer can be obtained on different apatite particles through a simple sol-gel synthesis route. Sol-gel derived powders of hydroxyapatite (HAP) and beta tricalciumphosphate (beta-TCP) were coated with a mesoporous silica using C16TAB (hexadecyltrimethylammonium bromide) as a template in order to induce mesophase formation. Further calcination of the material removes the template from the mesophase and leaves a highly ordered hexagonal arranged mesoporous silica structure with a core of HAP/beta-TCP. The phase purity of the SiO2/apatite composites has been thoroughly investigated by the means of FT-IR, XRD, and solid state 31P MAS NMR. The phase purity of these materials is shown to be dependent on the solubility properties of the used apatites. The hybrid materials are suitable as a multifunctional biomaterial where osteoconductive properties can be combined with drug delivery.

Fluid self-diffusion in Scots pine sapwood tracheid cells.

The self-diffusion coefficients of water and toluene in Scots pine sapwood was measured using low field pulsed field gradient nuclear magnetic resonance (PFG-NMR). Wood chips of 8 mm diameter were saturated with the respective liquids, and liquid self-diffusion was then traced in one dimension orthogonal to the tracheid cell walls in the wood's radial direction. The experimental echo attenuation curves were exponential, and characteristic self-diffusion coefficients were produced for diffusion times spanning from very short times to times on the order of magnitude of seconds. Observed self-diffusion coefficients were decaying asymptotically as a function of diffusion time, an effect which was ascribed to the cell walls' restriction on confined liquid diffusion. The observed self-diffusion behavior in Scots pine sapwood was compared to self-diffusion coefficients obtained from simulations of diffusion in a square. Principles of molecular displacements in confined geometries were used for elucidating the wood's cellular structure from the observed diffusion coefficients. The results were compared with a mathematical model for diffusion between parallel planes.

Aqueous microemulsions of a fluorinated surfactant and oil studied by PFG-NMR: transformation from threadlike to spherical micelles.

The aqueous microemulsion system consisting of the fluorinated surfactant tetraethylammonium perfluorooctylsulfonate (TEAFOS) and the fluorinated oil 1H-perfluorohexane (PFH) has been investigated using the pulsed field gradient NMR self-diffusion method on both 1H and 19F. Neat TEAFOS(aq) builds threadlike micelles from rather low surfactant concentrations up to ca. 80 mmol kg(-1). The addition of PFH to TEAFOS(aq) solutions induces a transition from threadlike micelles to spherical micelles solubilizing the oil. In this paper, information from the self-diffusion coefficients of oil (PFH), surfactant counterion (TEA+), surfactant ion (FOS-), and water (HDO) during the transition is presented.