269 research outputs found

    A scanning drift tube apparatus for spatio-temporal mapping of electron swarms

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    A "scanning" drift tube apparatus, capable of mapping of the spatio-temporal evolution of electron swarms, developing between two plane electrodes under the effect of a homogeneous electric field, is presented. The electron swarms are initiated by photoelectron pulses and the temporal distributions of the electron flux are recorded while the electrode gap length (at a fixed electric field strength) is varied. Operation of the system is tested and verified with argon gas, the measured data are used for the evaluation of the electron bulk drift velocity. The experimental results for the space-time maps of the electron swarms - presented here for the first time - also allow clear observation of deviations from hydrodynamic transport. The swarm maps are also reproduced by particle simulations

    Society for Endocrinology UK guidance on the initial evaluation of an infant or an adolescent with a suspected disorder of sex development (Revised 2015)

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    It is paramount that any child or adolescent with a suspected disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD. If there is any doubt, the case should be discussed with the regional DSD team. In most cases, particularly in the case of the newborn, the paediatric endocrinologist within the regional team acts commonly as the first point of contact. This clinician should be part of a multidisciplinary team experienced in management of DSD and should ensure that the affected person and parents have access to specialist psychological support and that their information needs are comprehensively addressed. The underlying pathophysiology of DSD and the strengths and weaknesses of the tests that can be performed should be discussed with the parents and affected young person and tests undertaken in a timely fashion. Finally, in the field of rare conditions, it is imperative that the clinician shares the experience with others through national and international clinical and research collaboration

    Society for Endocrinology UK guidance on the initial evaluation of an infant or an adolescent with a suspected disorder of sex development (Revised 2015).

    Get PDF
    It is paramount that any child or adolescent with a suspected disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD. If there is any doubt, the case should be discussed with the regional DSD team. In most cases, particularly in the case of the newborn, the paediatric endocrinologist within the regional team acts commonly as the first point of contact. This clinician should be part of a multidisciplinary team experienced in management of DSD and should ensure that the affected person and parents have access to specialist psychological support and that their information needs are comprehensively addressed. The underlying pathophysiology of DSD and the strengths and weaknesses of the tests that can be performed should be discussed with the parents and affected young person and tests undertaken in a timely fashion. Finally, in the field of rare conditions, it is imperative that the clinician shares the experience with others through national and international clinical and research collaboration

    Ethnicity and sexual risk in heterosexual people attending sexual health clinics in England: a cross-sectional, self-administered questionnaire study.

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    OBJECTIVES: In the UK, people of black ethnicity experience a disproportionate burden of HIV and STI. We aimed to assess the association of ethnicity with sexual behaviour and sexual health among women and heterosexual men attending genitourinary medicine (GUM) clinics in England. METHODS: The Attitudes to and Understanding of Risk of Acquisition of HIV is a cross-sectional, self-administered questionnaire study of HIV negative people recruited from 20 GUM clinics in England, 2013-2014. Modified Poisson regression with robust SEs was used to calculate adjusted prevalence ratios (aPR) for the association between ethnicity and various sexual risk behaviours, adjusted for age, study region, education and relationship status. RESULTS: Questionnaires were completed by 1146 individuals, 676 women and 470 heterosexual men. Ethnicity was recorded for 1131 (98.8%) participants: 550 (48.6%) black/mixed African, 168 (14.9%) black/mixed Caribbean, 308 (27.2%) white ethnic groups, 105 (9.3%) other ethnicity. Compared with women from white ethnic groups, black/mixed African women were less likely to report condomless sex with a non-regular partner (aPR (95% CI) 0.67 (0.51 to 0.88)), black/mixed African and black/mixed Caribbean women were less likely to report two or more new partners (0.42 (0.32 to 0.55) and 0.44 (0.29 to 0.65), respectively), and black/mixed Caribbean women were more likely to report an STI diagnosis (1.56 (1.00 to 2.42)). Compared with men from white ethnic groups, black/mixed Caribbean men were more likely to report an STI diagnosis (1.91 (1.20 to 3.04)), but did not report risk behaviours more frequently. Men and women of black/mixed Caribbean ethnicity remained more likely to report STI history after adjustment for sexual risk behaviours. DISCUSSION: Risk behaviours were reported less frequently by women of black ethnicity; however, history of STI was more prevalent among black/mixed Caribbean women. In black/mixed Caribbean men, higher STI history was not explained by ethnic variation in reported risk behaviours. The association between STI and black/mixed Caribbean ethnicity remained after adjustment for risk behaviours

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

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    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

    Evaluation and pharmacovigilance of projects promoting cultivation and local use of Artemisia annua for malaria

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    <p>Abstract</p> <p>Background</p> <p>Several non-governmental organisations (NGOs) are promoting the use of <it>Artemisia annua </it>teas as a home-based treatment for malaria in situations where conventional treatments are not available. There has been controversy about the effectiveness and safety of this approach, but no pharmacovigilance studies or evaluations have been published to date.</p> <p>Method</p> <p>A questionnaire about the cultivation of <it>A. annua</it>, treatment of patients, and side-effects observed, was sent to partners of the NGO Anamed in Kenya and Uganda. Some of the respondents were then selected purposively for more in-depth semi-structured interviews.</p> <p>Results</p> <p>Eighteen partners in Kenya and 21 in Uganda responded. 49% reported difficulties in growing the plant, mainly due to drought. Overall about 3,000 cases of presumed malaria had been treated with <it>A. annua </it>teas in the previous year, of which about 250 were in children and 54 were in women in the first trimester of pregnancy. The commonest problem observed in children was poor compliance due to the bitter taste, which was improved by the addition of sugar or honey. Two miscarriages were reported in pregnant patients. Only four respondents reported side-effects in other patients, the commonest of which was vomiting. 51% of respondents had started using <it>A. annua </it>tea to treat illnesses other than malaria.</p> <p>Conclusions</p> <p>Local cultivation and preparation of <it>A. annua </it>are feasible where growing conditions are appropriate. Few adverse events were reported even in children and pregnant women. Where ACT is in short supply, it would make sense to save it for young children, while using <it>A. annua </it>infusions to treat older patients who are at lower risk. An ongoing pharmacovigilance system is needed to facilitate reporting of any adverse events.</p

    Evaluation of strain and stress states in the single point incremental forming process

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    Single point incremental forming (SPIF) is a promising manufacturing process suitable for small batch production. Furthermore, the material formability is enhanced in comparison with the conventional sheet metal forming processes, resulting from the small plastic zone and the incremental nature. Nevertheless, the further development of the SPIF process requires the full understanding of the material deformation mechanism, which is of great importance for the effective process optimization. In this study, a comprehensive finite element model has been developed to analyse the state of strain and stress in the vicinity of the contact area, where the plastic deformation increases by means of the forming tool action. The numerical model is firstly validated with experimental results from a simple truncated cone of AA7075-O aluminium alloy, namely, the forming force evolution, the final thickness and the plastic strain distributions. In order to evaluate accurately the through-thickness gradients, the blank is modelled with solid finite elements. The small contact area between the forming tool and the sheet produces a negative mean stress under the tool, postponing the ductile fracture occurrence. On the other hand, the residual stresses in both circumferential and meridional directions are positive in the inner skin of the cone and negative in the outer skin. They arise predominantly along the circumferential direction due to the geometrical restrictions in this direction.The authors would like to gratefully acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) under project PTDC/EMS-TEC/1805/2012. The first author is also grateful to the FCT for the postdoctoral grant SFRH/BPD/101334/2014.info:eu-repo/semantics/publishedVersio

    A participatory intervention to improve the mental health of widows of injecting drug users in north-east India as a strategy for HIV prevention

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    BACKGROUND: Manipur and Nagaland, in the north-east of India, are classified as high prevalence states for HIV, and intravenous drug use is an important route of transmission. Most injecting drug users (IDUs) are men, an estimated 40% are married, and death rates have been high in the last five years, consequently the number of widows of IDUs has increased. Many of these widows and their children are HIV-infected and experience poor health, discrimination, and impoverishment; all factors likely to be compromising their mental health. People with poor mental health are more likely to engage in HIV risk behaviours. Mental health can be promoted by public health actions with vulnerable population groups. METHODS: We designed an intervention study to assess the feasibility and impact of a participatory action process to promote the mental health and well-being of widows of IDUs in Manipur and Nagaland, as a strategy for reducing the risk of engagement in HIV risk behaviours. This paper describes the background and rationale for the study, the intervention, and the study methods in detail. RESULTS: Pending analysis. CONCLUSION: This intervention study will make a significant contribution to the emerging evidence that supports associations between mental health and HIV. The concept of promoting mental health among women who are vulnerable to HIV infection or already infected as a strategy for HIV prevention in a development setting is breaking new ground
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