721 research outputs found

    Improving health outcomes for girls : reflections on the impact on body issue of a girl\u27s only health and physical education intervention

    Get PDF
    Background: The issues surrounding girls' lack of participation in physical activity are many and varied, but\ud generally relate to the broader social context of adolescent health in which the social relations of gender play a significant part in a lack of engagement with sports; with a lack of physical skills and confidence for\ud equitable participation; friendship considerations; body image issues and a concern about bullying and\ud harassment.\ud \ud Objectives: This paper reports on data collected as part of a larger project researching the impact of a non-traditional physical education and health intervention designed to build girls connectedness to each other,\ud their school and their community by engaging them in a girls' only negotiated physical activity program that\ud was supported by a targeted health education curricula.\ud \ud Underlying values and principles: Grade 8 girls in the State of Victoria, Australia have the lowest school\ud connectedness data than any other cohort. Using youth participation principles and underpinned by strong\ud educational guidelines an integrated health and physical education program was developed by a high school\ud in Australia in an attempt to improve connectedness. It facilitated the exploration of a number of different\ud lifestyle physical activities such as bellying dance, self-defense and yoga, to engage the girls with alternative\ud physical activities that were potentially available in their community as well as discussion and activities on\ud sexuality, body image and mental health.\ud \ud Knowledge base/ Evidence base: Whilst evaluation of girls' only physical activity programs are not new,\ud research into the impact of an integrated school-based health and physical education curricula are and have\ud implications for future school based approaches.\ud \ud Context of intervention/project/work: The project initially focused on adolescent girls at a small 7-12\ud Secondary College in an isolated community approximately 200 kilometres from the Capital city of Victoria. A\ud grant was awarded to a consortium of local/regional agencies to implement and extend the program over\ud three years. Overwhelmingly the program was conducted by regional and local agencies in conjunction with\ud the local secondary school. It is a partnerships model built on the notion of increasing participation and\ud access for young women whilst building a sustainable program run in partnership with the school and local\ud agencies and services. In 2009 the program was also run in a metropolitan secondary school that had a\ud similar socia-economic background. This paper draws on data from both schools.\ud \ud Methods: This paper reports on qualitative date collected on young women's perceptions of the program, its\ud contribution to their health and wellbeing and the impact of the program on understandings of health related\ud issues of relevance to young women. The data is drawn from focus group data collected from two high\ud schools in the state of Victoria, Australia in 2007, 2008 and 2009. Sixty five girls' in grade 7, 8, 9 and 10\ud participated in the pre and post program interviews.\ud \ud Results and Conclusions: We argue that whilst the data indicates that a girls only program can have a\ud pOSitive impact on aspect of connectedness such as relationships with their peers, reducing bullying\ud behaviour, the data raises some important questions around the adequacy of school-based health education,\ud and the sustainability of approaches designed to be delivered by outside agencies rather than classroom\ud teachers. We argue that whilst single sex health and physical education programs may be necessary for girls\ud to participate and engage fully, the current approach has little impact on traditional notions of gender and\ud body issues.\ud \ud Disclosure of Interest: Centre for Educational Futures and Innovation, Grant Research Support. Victorian Health Promotion Foundation, Grant Research Support

    The Escherichia coli glucuronylsynthase promoted synthesis of steroid glucuronides: improved practicality and broader scope

    No full text
    A library of steroid glucuronides was prepared using the glucuronylsynthase derived from Escherichia coliβ-glucuronidase, followed by purification using solid-phase extraction. A representative range of steroid substrates were screened for synthesis on the milligram scale under optimised conditions with conversions dependent on steroid substitution and stereochemistry. Epiandrosterone (3β-hydroxy-5α-androstan-17-one) provided the highest conversion of 90% (84% isolated yield). The previously unreported glucuronide conjugates of methandriol (17α-methylandrost-5-ene-3β,17β-diol), cholest-5-ene-3β,25-diol and the designer steroid trenazone (17β-hydroxyestra-4,9-dien-3-one) were prepared on a multi-milligram scale suitable for characterisation by (1)H and (13)C NMR spectroscopy. The glucuronide conjugate of d5-etiocholanolone (2,2,3,4,4-d5-3α-hydroxy-5β-androstan-17-one), a target developed by the World Anti-Doping Agency as a certified reference material, was also prepared on a milligram scale. The improved E. coli glucuronylsynthase method provides for the rapid synthesis and purification of steroid glucuronides on a scale suitable for a range of analytical applications.Australian Research Council (DP110101235

    Pt-incorporated anatase TiO2(001) surface for solar cell applications : First-principles density functional theory calculations

    Get PDF
    First-principles density functional theory calculations were carried out to determine the low energy geometries of anatase TiO2_2(001) with Pt implants in the sublayers as substitutional and interstitial impurities as well as on the surface in the form of adsorbates. We investigated the effect of such a systematic Pt incorporation in the electronic structure of this surface for isolated and interacting impurities with an emphasis on the reduction in the band gap to visible region. Comprehensive calculations, for 1x1 surface, showed that Pt ions at interstitial cavities result in local segregation, forming metallic wires inside, while substitution for bulk Ti and adsorption drives four strongly dispersed impurity states from valence-bands up in the gap with a narrowing of ~1.5 eV. Hence, such a contiguous Pt incorporation drives anatase into infrared regime. Pt substitution for the surface Ti, on the other hand, metallizes the surface. Systematic trends for 2x2 surface revealed that Pt can be encapsulated inside to form stable structures as a result of strong Pt-O interactions as well as the adsorptional and substitutional cases. Dilute impurities considered for 2x2 surface models exhibit flat-like defect states driven from the valence bands narrowing the energy gap suitable to obtain visible light responsive titania.Comment: 15 pages, 8 figures, 4 tables. to appear on Phys. Rev

    Pseudomonas aeruginosa arylsulfatase: a purified enzyme for the mild hydrolysis of steroid sulfates

    No full text
    The hydrolysis of sulfate ester conjugates is frequently required prior to analysis for a range of analytical techniques including gas chromatography-mass spectrometry (GC-MS). Sulfate hydrolysis may be achieved with commercial crude arylsulfatase enzyme preparations such as that derived from Helix pomatia but these contain additional enzyme activities such as glucuronidase, oxidase, and reductase that make them unsuitable for many analytical applications. Strong acid can also be used to hydrolyze sulfate esters but this can lead to analyte degradation or increased matrix interference. In this work, the heterologously expressed and purified arylsulfatase from Pseudomonas aeruginosa is shown to promote the mild enzyme-catalyzed hydrolysis of a range of steroid sulfates. The substrate scope of this P. aeruginosa arylsulfatase hydrolysis is compared with commercial crude enzyme preparations such as that derived from H. pomatia. A detailed kinetic comparison is reported for selected examples. Hydrolysis in a urine matrix is demonstrated for dehydroepiandrosterone 3-sulfate and epiandrosterone 3-sulfate. The purified P. aeruginosa arylsulfatase contains only sulfatase activity allowing for the selective hydrolysis of sulfate esters in the presence of glucuronide conjugates as demonstrated in the short three-step chemoenzymatic synthesis of 5α-androstane-3β,17β-diol 17-glucuronide (ADG, 1) from epiandrosterone 3-sulfate. The P. aeruginosa arylsulfatase is readily expressed and purified (0.9 g per L of culture) and thus provides a new and selective method for the hydrolysis of steroid sulfate esters in analytical sample preparation.We thank the Australian Government Anti-Doping Research Pro-gram for financial support

    Anomalous scattering analysis of Agrobacterium radiobacter phosphotriesterase: the prominent role of iron in the heterobinuclear active site

    Get PDF
    Bacterial phosphotriesterases are binuclear metalloproteins from which the catalytic mechanism has been studied with a variety of techniques, principally using active sites reconstituted in vitro from apo-enzymes. Here, atomic absorption spectroscopy and anomalous X-ray scattering and have been used to determine the identity of the metals incorporated into the active site in vivo. We have recombinantly expressed the phosphotriesterase from Agrobacterium radiobacter (OpdA) in Escherichia coli grown in medium supplemented with 1 mM CoCl2, and in unsupplemented medium. Anomalous scattering data, collected from a single crystal at the Fe-K, Co-K and Zn-K edges, indicate that iron and cobalt are the primary constituents of the two metal binding sites in the catalytic centre ( and ), in protein expressed in E. coli grown in supplemented medium. Comparison to OpdA expressed in unsupplemented medium demonstrates that the cobalt present in the supplemented medium replaced zinc at the -position of the active site, which results in an increase in the catalytic efficiency of the enzyme. These results suggest an essential role for iron in the catalytic mechanism of bacterial phosphotriesterases, and that they are natively heterobinuclear iron-zinc enzymes

    Status of the Nif Power Conditioning System

    Get PDF
    The NIF Power Conditioning System provides the pulsed excitation required to drive flashlamps in the laser's optical amplifiers. Modular in design, each of the 192 Main Energy Storage Modules (MESMs) storage up to 2.2 MJ of electrical energy in its capacitor bank before delivering the energy to 20 pairs of flashlamps in a 400 {micro}s pulse (10% power points). The peak current of each MESM discharge is 0.5 MA. Production, installation, commissioning and operation of the NIF Power Conditioning continue to progress rapidly, with the goals of completing accelerated production in late 2007 and finishing commissioning by early 2008, all the while maintaining an aggressive operations schedule. To date, more than 80% of the required modules have been assembled, shipped and installed in the facility, representing more that 240 MJ of stored energy available for driving NIF flashlamps. The MESMs have displayed outstanding reliability during daily, multiple-shift operations

    Repositioning the Catalytic Triad Aspartic Acid of Haloalkane Dehalogenase: Effects on Stability, Kinetics, and Structure

    Get PDF
    Haloalkane dehalogenase (DhlA) catalyzes the hydrolysis of haloalkanes via an alkyl-enzyme intermediate. The covalent intermediate, which is formed by nucleophilic substitution with Asp124, is hydrolyzed by a water molecule that is activated by His289. The role of Asp260, which is the third member of the catalytic triad, was studied by site-directed mutagenesis. Mutation of Asp260 to asparagine resulted in a catalytically inactive D260N mutant, which demonstrates that the triad acid Asp260 is essential for dehalogenase activity. Furthermore, Asp260 has an important structural role, since the D260N enzyme accumulated mainly in inclusion bodies during expression, and neither substrate nor product could bind in the active-site cavity. Activity for brominated substrates was restored to D260N by replacing Asn148 with an aspartic or glutamic acid. Both double mutants D260N+N148D and D260N+N148E had a 10-fold reduced kcat and 40-fold higher Km values for 1,2-dibromoethane compared to the wild-type enzyme. Pre-steady-state kinetic analysis of the D260N+N148E double mutant showed that the decrease in kcat was mainly caused by a 220-fold reduction of the rate of carbon-bromine bond cleavage and a 10-fold decrease in the rate of hydrolysis of the alkyl-enzyme intermediate. On the other hand, bromide was released 12-fold faster and via a different pathway than in the wild-type enzyme. Molecular modeling of the mutant showed that Glu148 indeed could take over the interaction with His289 and that there was a change in charge distribution in the tunnel region that connects the active site with the solvent. On the basis of primary structure similarity between DhlA and other α/β-hydrolase fold dehalogenases, we propose that a conserved acidic residue at the equivalent position of Asn148 in DhlA is the third catalytic triad residue in the latter enzymes.

    Structure and function of an insect α-carboxylesterase (α Esterase 7) associated with insecticide resistance

    Get PDF
    Insect carboxylesterases from the αEsterase gene cluster, such as αE7 (also known as E3) from the Australian sheep blowfly Lucilia cuprina (LcαE7), play an important physiological role in lipid metabolism and are implicated in the detoxification of or

    The sphere-in-contact model of carbon materials

    Get PDF
    A sphere-in-contact model is presented that is used to build physical models of carbon materials such as graphite, graphene, carbon nanotubes and fullerene. Unlike other molecular models, these models have correct scale and proportions because the carbon atoms are represented by their atomic radius, in contrast to the more commonly used space-fill models, where carbon atoms are represented by their van der Waals radii. Based on a survey taken among 65 undergraduate chemistry students and 28 PhD/postdoctoral students with a background in molecular modeling, we found misconceptions arising from incorrect visualization of the size and location of the electron density located in carbon materials. Based on analysis of the survey and on a conceptual basis we show that the sphere-in-contact model provides an improved molecular representation of the electron density of carbon materials compared to other molecular models commonly used in science textbooks (i.e., wire-frame, ball-and-stick, space-fill). We therefore suggest that its use in chemistry textbooks along with the ball-and-stick model would significantly enhance the visualization of molecular structures according to their electron density

    Second chances: Investigating athletes’ experiences of talent transfer

    Get PDF
    Talent transfer initiatives seek to transfer talented, mature individuals from one sport to another. Unfortunately talent transfer initiatives seem to lack an evidence-based direction and a rigorous exploration of the mechanisms underpinning the approach. The purpose of this exploratory study was to identify the factors which successfully transferring athletes cite as facilitative of talent transfer. In contrast to the anthropometric and performance variables that underpin current talent transfer initiatives, participants identified a range of psychobehavioral and environmental factors as key to successful transfer. We argue that further research into the mechanisms of talent transfer is needed in order to provide a strong evidence base for the methodologies employed in these initiatives
    corecore