3D Coronal Density Reconstruction and Retrieving the Magnetic Field Structure during Solar Minimum

Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal phenomena at all scales. We employed STEREO/COR1 data obtained during a deep minimum of solar activity in February 2008 (Carrington rotation CR 2066) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 Rsun using a tomography method. With this, we qualitatively deduced structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in the 195 A band obtained by tomography for the same CR. A global 3D MHD model of the solar corona was used to relate the reconstructed 3D density and emissivity to open/closed magnetic field structures. We show that the density maximum locations can serve as an indicator of current sheet position, while the locations of the density gradient maximum can be a reliable indicator of coronal hole boundaries. We find that the magnetic field configuration during CR 2066 has a tendency to become radially open at heliocentric distances greater than 2.5 Rsun. We also find that the potential field model with a fixed source surface (PFSS) is inconsistent with the boundaries between the regions with open and closed magnetic field structures. This indicates that the assumption of the potential nature of the coronal global magnetic field is not satisfied even during the deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.Comment: Published in "Solar Physics

Developing young people's sense of self and place through sport

Previous research has recognized positive health implications, both physical and mental, as an outcome of participation in leisure pursuits. They provide opportunities for self-expression and stress reduction, as well as an environment in which people can socialize. Leisure activities, specifically sport activities, can play a significant role in young people's identity development. This paper explores the leisure activities in which young people in Adelaide, Australia participate. It examines the role of leisure activities in terms of young people's identity and feelings towards their hometown. This study consisted of semi-structured focus groups conducted with 24 senior high school students, followed by a survey resulting in 226 useable responses. Respondents were aged between 16 and 18 years of age. From the range of activities identified and explored, the results revealed sports activities to have the greatest impact on young people's lives. The results demonstrated that frequency of participation has a significant effect on young people's involvement levels and how they identify with the activity

Molecularly imprinted solid-phase extraction of diazepam and its metabolites from hair samples

An anti-diazepam, molecularly imprinted polymer (MIP) has been synthesized and used to extract diazepam and other benzodiazepines from hair samples via a molecularly imprinted solid-phase extraction (MISPE) protocol. Optimum retention of diazepam on the MIP columns was achieved using an apolar solvent, and the binding capacity of the polymer toward diazepam was found to be 110 ng of diazepam/mg of polymer. The recovery of a 50 ng diazepam standard spiked into blank hair was 93%, with good precision (RSD = 1.5%). The LOD and LOQ of diazepam in spiked hair samples were 0.09 and 0.14 ng/mg, respectively. The MISPE method was demonstrated to be applicable to the analysis of diazepam metabolites and other benzodiazepine drugs, in addition to diazepam itself. The application of the extraction method to postmortem hair samples yielded results that were in good agreement with the corresponding ELISA data (from blood samples) and data arising from the analysis of the same blood samples using a validated in-house SPE-LC−MS−MS method

Multidentate macromolecules for functionalisation, passivation and labelling of metal nanoparticles

A new class of SERRS-active macromolecule designed to protect silver nanoparticle surfaces against salt corrosion whilst retaining colloidal stability of the particles is reported. (from: http://www.rsc.org/Publishing/Journals/CC/article.asp?doi=b801010b

Spherical molecularly imprinted polymer particles: A promising tool for molecular recognition in capillary electrokinetic separations

Spherical molecularly imprinted polymer particles obtained via precipitation polymerization, were introduced as a pseudostationary phase in capillary electrophoresis (CE) to study molecular recognition. Analyses were performed via a partial filling technique using (+)-ephedrine-imprinted microspheres (100-200 nm) which were polymerized from methacrylic acid and 1,1,1-Tris(hydroxymethyl)propanetrimethacrylate using acetonitrile as the solvent. The influence of pH and the modifier content on the separation was investigated. A 0.1 % w/v suspension in an aqueous 10 mm phosphate buffer (pH 2.5 with 40% acetonitrile) was hydrodynamically injected into the CE system (80% of the effective capillary length) and led to full baseline separation of racemic ephedrine within 10 min

SERRS labelled beads for multiplex detection

Beads labelled using surface enhanced resonance Raman scattering (SERRS) are highly sensitive and specific tags, with potential applications in biological assays, including molecular diagnostics. The beads consist of a nucleus containing dye labelled silver-nanoparticle aggregates surrounded by a polymer core. The nuclei generate strong SERRS signals. To illustrate the coding advantage created by the sharp, molecularly specific SERRS signals, four specially designed SERRS dyes have been used as labels and three of these have been combined in a multiplex analysis. These dyes use specific groups such as benzotriazole and 8-hydroxyquinoline to improve binding to the surface of the silver particles. The aggregation state of the particles is held constant by the polymer core, this nucleus also contains many dye labels, yielding a very high Raman scattering intensity for each bead. To functionalise these beads for use in biological assays an outer polymer shell can be added, which allows the attachment of oligonucleotide probes. Oligonucleotide modified beads can then be used for detection of specific oligonucleotide targets. The specificity of SERRS will allow for the detection of multiple targets within a single assay