329 research outputs found

    Willingness to participate in future HIV prevention studies among gay and bisexual men in Scotland, UK: a challenge for intervention trials

    Get PDF
    This article examines willingness to participate in future HIV prevention research among gay and bisexual men in Scotland, UK. Anonymous, self-complete questionnaires and Orasure Gäó oral fluid samples were collected in commercial gay venues. 1,320 men were eligible for inclusion. 78.2% reported willingness to participate in future HIV prevention research; 64.6% for an HIV vaccine, 57.4% for a behaviour change study, and 53.0% for a rectal microbicide. In multivariate analysis, for HIV vaccine research, greater age, minority ethnicity, and not providing an oral fluid sample were associated with lower willingness; heterosexual orientation and not providing an oral fluid sample were for microbicides; higher education and greater HIV treatment optimism were for behaviour change. STI testing remained associated with being more willing to participate in microbicide research and frequent gay scene use remained associated with being more willing to participate in behaviour change research. Having an STI in the past 12 months remained significantly associated with being willing to participate in all three study types. There were no associations between sexual risk behaviour and willingness. Although most men expressed willingness to participate in future research, recruitment of high-risk men, who have the potential to benefit most, is likely to be more challenging

    Normal modes of a small gamelan gong

    Get PDF
    © 2014 Acoustical Society of America. Studies have been made of the normal modes of a 20.7 cm diameter steel gamelan gong. A finite-element model has been constructed and its predictions for normal modes compared with experimental results obtained using electronic speckle pattern interferometry. Agreement was reasonable in view of the lack of precision in the manufacture of the instrument. The results agree with expectations for an axially symmetric system subject to small symmetry breaking. The extent to which the results obey Chladni's law is discussed. Comparison with vibrational and acoustical spectra enabled the identification of the small number of modes responsible for the sound output when played normally. Evidence of non-linear behavior was found, mainly in the form of subharmonics of true modes. Experiments using scanning laser Doppler vibrometry gave satisfactory agreement with the other methods

    All-sky interferometric meteor radar meteoroid speed estimation using the Fresnel transform

    Get PDF
    Fresnel transform meteor speed estimation is investigated. A spectral based technique is developed allowing the transform to be applied at low temporal sampling rates. Simulations are used to compare meteoroid speeds determined using the Fresnel transform and alternative techniques, confirming that the Fresnel transform produces the most accurate meteoroid speed estimates for high effective pulse repetition frequencies (PRFs). The Fresnel transform is applied to high effective PRF data collected during Leonid meteor showers, producing speed estimates in good agreement with the theoretical pre-atmospheric speed of the 71 kms−1. Further simulations for the standard low effective PRF sampling parameters used for Buckland Park meteor radar (BPMR) observations suggests that the Fresnel transform can successfully estimate meteor speeds up to 80 kms−1. Fresnel transform speed estimation is applied using the BPMR, producing speed distributions similar to those obtained in previous studies. The technique is also applied to data collected using the BPMR sampling parameters during Southern delta-Aquarid and Geminid meteor showers, producing speeds in very good agreement with the theoretical pre-atmospheric speeds of these showers (41 kms−1 and 35 kms−1, respectively). However, application of the Fresnel transform to high speed showers suggests that the practical upper limit for accurate speed estimation using the BPMR sampling parameters is around 50 kms−1. This limit allows speed accurate estimates to be made for about 70% of known meteor showers, and around 70% of sporadic echoes.D. A. Holdsworth, W. G. Elford, R. A. Vincent, I. M. Reid, D. J. Murphy, and W. Singe

    Anti-plasmodial polyvalent interactions in Artemisia annua L. aqueous extract – possible synergistic and resistance mechanisms

    Get PDF
    Artemisia annua hot water infusion (tea) has been used in in vitro experiments against P. falciparum malaria parasites to test potency relative to equivalent pure artemisinin. High performance liquid chromatography (HPLC) and mass spectrometric analyses were employed to determine the metabolite profile of tea including the concentrations of artemisinin (47.5±0.8 mg L-1), dihydroartemisinic acid (70.0±0.3 mg L-1), arteannuin B (1.3±0.0 mg L-1), isovitexin (105.0±7.2 mg L-1) and a range of polyphenolic acids. The tea extract, purified compounds from the extract, and the combination of artemisinin with the purified compounds were tested against chloroquine sensitive and chloroquine resistant strains of P. falciparum using the DNA-intercalative SYBR Green I assay. The results of these in vitro tests and of isobologram analyses of combination effects showed mild to strong antagonistic interactions between artemisinin and the compounds (9-epi-artemisinin and artemisitene) extracted from A. annua with significant (IC50 <1 μM) anti-plasmodial activities for the combination range evaluated. Mono-caffeoylquinic acids, tri-caffeoylquinic acid, artemisinic acid and arteannuin B showed additive interaction while rosmarinic acid showed synergistic interaction with artemisinin in the chloroquine sensitive strain at a combination ratio of 1:3 (artemisinin to purified compound). In the chloroquine resistant parasite, using the same ratio, these compounds strongly antagonised artemisinin anti-plasmodial activity with the exception of arteannuin B, which was synergistic. This result would suggest a mechanism targeting parasite resistance defenses for arteannuin B’s potentiation of artemisinin

    Methodological challenges in collecting social and behavioural data regarding the HIV epidemic among gay and other men who have sex with men in Australia

    Get PDF
    ©2014 Zablotska et al. Background: Behavioural surveillance and research among gay and other men who have sex with men (GMSM) commonly relies on non-random recruitment approaches. Methodological challenges limit their ability to accurately represent the population of adult GMSM. We compared the social and behavioural profiles of GMSM recruited via venue-based, online, and respondent-driven sampling (RDS) and discussed their utility for behavioural surveillance. Methods: Data from four studies were selected to reflect each recruitment method. We compared demographic characteristics and the prevalence of key indicators including sexual and HIV testing practices obtained from samples recruited through different methods, and population estimates from respondent-driven sampling partition analysis. Results: Overall, the socio-demographic profile of GMSM was similar across samples, with some differences observed in age and sexual identification. Men recruited through time-location sampling appeared more connected to the gay community, reported a greater number of sexual partners, but engaged in less unprotected anal intercourse with regular (UAIR) or casual partners (UAIC). The RDS sample overestimated the proportion of HIV-positive men and appeared to recruit men with an overall higher number of sexual partners. A single-website survey recruited a sample with characteristics which differed considerably from the population estimates with regards to age, ethnically diversity and behaviour. Data acquired through time-location sampling underestimated the rates of UAIR and UAIC, while RDS and online sampling both generated samples that underestimated UAIR. Simulated composite samples combining recruits from time-location and multi-website online sampling may produce characteristics more consistent with the population estimates, particularly with regards to sexual practices. Conclusion: Respondent-driven sampling produced the sample that was most consistent to population estimates, but this methodology is complex and logistically demanding. Time-location and online recruitment are more cost-effective and easier to implement; using these approaches in combination may offer the potential to recruit a more representative sample of GMSM

    Developing a Text Messaging Risk Reduction Intervention for Methamphetamine-Using MSM: Research Note

    Get PDF
    Men who have sex with men (MSM) who use methamphetamine experience high risks for HIV infection due to sexual transmission behaviors often engaged in when under the influence of methamphetamine. Methamphetamine-using MSM use various forms of information technology (IT) communication such as instant messaging, social networking sites, and websites to facilitate a sexual and/or drug “hook up.” Given the acceptability of IT communication in their daily lives, an IT intervention represents an appropriate strategy to reach and intervene with out-of-treatment, methamphetamine-using MSM. The aim of this study was to conduct formative work to develop a text messaging intervention to reduce methamphetamine use and high-risk sexual behaviors among out-of-treatment MSM, which involved conducting focus groups, community partners’ meetings, and a pre-test intervention. These activities culminated in the development of a two-week, text-messaging intervention that delivered real-time electronic correspondence based on the behavioral change theories of Social Support Theory, Health Belief Model, and Social Cognitive Theory. The focus groups, community meetings, and pre-test were used to identify the IT communication device, the text messages that best support risk reduction and healthier behavioral choices, and logo, flyer and website development. The input and feedback from the target population and community partners were critical to the successful development of a culturally appropriate intervention. The knowledge gleaned from the formative work of this study will be vitally helpful in designing future IT studies
    corecore