Influence of a transverse static magnetic field on the magnetic hyperthermia properties and high-frequency hysteresis loops of ferromagnetic FeCo nanoparticles

The influence of a transverse static magnetic field on the magnetic hyperthermia properties is studied on a system of large-losses ferromagnetic FeCo nanoparticles. The simultaneous measurement of the high-frequency hysteresis loops and of the temperature rise provides an interesting insight into the losses and heating mechanisms. A static magnetic field of only 40 mT is enough to cancel the heating properties of the nanoparticles, a result reproduced using numerical simulations of hysteresis loops. These results cast doubt on the possibility to perform someday magnetic hyperthermia inside a magnetic resonance imaging setup.Comment: 6 pages, 3 figure

Changing Patterns of Sexual Risk Behavior Among London Gay Men: 1998-2008

Objectives: To examine changes in the sexual behavior of London gay men between 1998 and 2008. Methods: Gay men using London gyms were surveyed annually between 1998 and 2005, and again in 2008 (n = 6064; range, 482–834 per year). Information was collected on human immunodeficiency virus (HIV) status of the respondent, unprotected anal intercourse (UAI) in the previous 3 months, type (main or casual) and HIV status of partner for UAI. Nonconcordant UAI (ncUAI) was defined as UAI with a partner of unknown or discordant HIV status. Concordant UAI (cUAI) was defined as UAI with a partner of the same HIV status (“serosorting”). Results: Between 1998 and 2008, the percentage of men reporting UAI increased from 24.3% to 36.6% (P = 0.07). This overall increase concealed important differences between nonconcordant and concordant UAI. While the percentage of men engaging in cUAI increased steadily between 1998 and 2008 (9.8%, 20.8%; P = 0.01), the percentage reporting ncUAI increased between 1998 and 2001 (14.5%, 23.7%; P < 0.001), decreased between 2001 and 2005 (23.7%, 15.6%; P < 0.001), and then leveled off between 2005 and 2008 (15.6%, 15.7%; P = 0.2). However, the percentage of men reporting ncUAI with a main partner increased between 2005 and 2008 for HIV-positive men (2.5%, 8.1%; P < 0.05) and HIV negative men (2.1%, 5.5%; P = 0.06). While the percentage of HIV negative men who reported cUAI with a main partner (i.e., serosorting) increased between 1998 and 2008 (12.4%, 21.1%; P < 0.05), less than half established seroconcordance by testing together. Conclusions: The patterns of sexual behavior among London's gay men between 1998 and 2008 were dynamic and complex. Our data suggest that HIV risk with a main partner and HIV testing among couples should be given greater priority by health promotion programmes

Visually guided grasping to study teleprogrammation within the BAROCO testbed

This paper describes vision functionalities required in future orbital laboratories; in such systems, robots will be needed in order to execute the on-board scientific experiments or servicing and maintenance tasks under the remote control of ground operators. For this sake, ESA has proposed a robotic configuration called EMATS; a testbed has been developed by ESTEC in order to evaluate the potentialities of EMATS-like robot to execute scientific tasks in automatic mode. For the same context, CNES develops the BAROCO testbed to investigate remote control and teleprogrammation, in which high level primitives like 'Pick Object A' are provided as basic primitives. In nominal situations, the system has an a priori knowledge about the position of all objects. These positions are not very accurate, but this knowledge is sufficient in order to predict the position of the object which must be grasped, with respect to the manipulator frame. Vision is required in order to insure a correct grasping and to guarantee a good accuracy for the following operations. We describe our results about a visually guided grasping of static objects. It seems to be a very classical problem, and a lot of results are available. But, in many cases, it lacks a realistic evaluation of the accuracy, because such an evaluation requires tedious experiments. We propose several results about calibration of the experimental testbed, recognition algorithms required to locate a 3D polyhedral object, and the grasping itself

Loss to Follow-Up Among Adults Attending Human Immunodeficiency Virus Services in England, Wales, and Northern Ireland

AIM: To assess the extent to which human immunodeficiency virus (HIV)-diagnosed adults attending HIV-services in England, Wales, and Northern Ireland are lost to follow-up or attend services intermittently. METHODS: A cohort of HIV-diagnosed adults was created by linking records across the 1998 to 2007 national annual Survey of Prevalent HIV Infections Diagnosed. The records were also linked to the national HIV and acquired immune deficiency syndrome New Diagnoses Database (n = 61,495) and to Office for National Statistics death records. Patterns of HIV-service attendance were analyzed. RESULTS: On average, 90% of adults attending HIV-services in any one year attended the following year. Nearly 5% of adults attending services in any one year were lost to follow-up, a further 4% subsequently attended services intermittently, whereas less than 2% died. Cumulatively, 19% of adults seen for HIV care between 1998 and 2006 were lost to follow-up by the end of 2007. Factors associated with loss to follow-up included being the following: female; aged 15 to 34 years; black-African or "other" ethnicity; not on antiretroviral therapy; recently diagnosed; and infected outside the United Kingdom. CONCLUSIONS: Although the majority of HIV-diagnosed adults in England, Wales, and Northern Ireland attended HIV-services regularly, cumulatively nearly 1 in 5 adults were lost to follow-up between 1998 and 2007. Innovative strategies focusing on those most likely to drop out of regular care should be developed to maintain regular service engagement and to ensure optimal care

The menopause transition in women living with HIV: current evidence and future avenues of research

As the life expectancy of people living with HIV improves as a result of antiretroviral therapy, increasing numbers of women living with HIV (WLHIV) are now reaching menopausal age. The menopause transition in WLHIV remains a relatively overlooked area in clinical HIV research. Whilst there is some evidence to suggest that WLHIV experience menopause at an earlier age and that they have more menopausal symptoms, there is no clear consensus in the literature around an impact of HIV infection on either timing or symptomatology of the menopause. Data are also conflicting on whether HIV-related factors such as HIV viral load and CD4 cell count have an impact on the menopause. Furthermore, menopausal symptoms in WLHIV are known to go under-recognised by both healthcare providers and women themselves. There is likely to be a burden of unmet health needs among WLHIV transitioning through the menopause, with significant gaps in the evidence base for their care. With this in mind, we have developed the PRIME study (Positive Transitions Through the Menopause). This mixed-methods observational study will explore, for the first time in the UK, the impact of the menopause on the health and wellbeing of 1500 ethnically diverse WLHIV. In establishing a cohort of women in their midlife and following them up longitudinally, we hope to develop a nuanced understanding of the gendered aspects of ageing and HIV, informing the provision of appropriate services for WLHIV to ensure that they are supported in maintaining optimal health and wellbeing as they get older

Loss to Follow-Up After Pregnancy Among Sub-Saharan Africa-Born Women Living With Human Immunodeficiency Virus in England, Wales and Northern Ireland: Results From a Large National Cohort.

BACKGROUND: Little is known about retention in human immunodeficiency virus (HIV) care in HIV-positive women after pregnancy in the United Kingdom. We explored the association between loss to follow-up (LTFU) in the year after pregnancy, maternal place of birth and duration of UK residence, in HIV-positive women in England, Wales, and Northern Ireland. METHODS: We analyzed combined data from 2 national data sets: the National Study of HIV in Pregnancy and Childhood; and the Survey of Prevalent HIV Infections Diagnosed, including pregnancies in 2000 to 2009 in women with diagnosed HIV. Logistic regression models were fitted with robust standard errors to estimate adjusted odds ratios (AOR). RESULTS: Overall, 902 of 7211 (12.5%) women did not access HIV care in the year after pregnancy. Factors associated with LTFU included younger age, last CD4 in pregnancy of 350 cells/μL or greater and detectable HIV viral load at the end of pregnancy (all P < 0.001). On multivariable analysis, LTFU was more likely in sub-Saharan Africa-born (SSA-born) women than white UK-born women (AOR, 2.17; 95% confidence interval, 1.50-3.14; P < 0.001). The SSA-born women who had migrated to the UK during pregnancy were 3 times more likely than white UK-born women to be lost to follow-up (AOR, 3.19; 95% confidence interval, 1.94-3.23; P < 0.001). CONCLUSIONS: One in 8 HIV-positive women in England, Wales, and Northern Ireland did not return for HIV care in the year after pregnancy, with SSA-born women, especially those who migrated to the United Kingdom during pregnancy, at increased risk. Although emigration is a possible explanatory factor, disengagement from care may also play a role

Primary care consultations and costs among HIV-positive individulas in UK primary care 1995-2005: a cohort study

Objectives: To investigate the role of primary care in the management of HIV and estimate primary care-associated costs at a time of rising prevalence. Methods: Retrospective cohort study between 1995 and 2005, using data from general practices contributing data to the UK General Practice Research Database. Patterns of consultation and morbidity and associated consultation costs were analysed among all practice-registered patients for whom HIV-positive status was recorded in the general practice record. Results: 348 practices yielded 5504 person-years (py) of follow-up for known HIV-positive patients, who consult in general practice frequently (4.2 consultations/py by men, 5.2 consultations/py by women, in 2005) for a range of conditions. Consultation rates declined in the late 1990s from 5.0 and 7.3 consultations/py in 1995 in men and women, respectively, converging to rates similar to the wider population. Costs of consultation (general practitioner and nurse, combined) reflect these changes, at £100.27 for male patients and £117.08 for female patients in 2005. Approximately one in six medications prescribed in primary care for HIV-positive individuals has the potential for major interaction with antiretroviral medications. Conclusion: HIV-positive individuals known in general practice now consult on a similar scale to the wider population. Further research should be undertaken to explore how primary care can best contribute to improving the health outcomes of this group with chronic illness. Their substantial use of primary care suggests there may be potential to develop effective integrated care pathways

A Bayesian framework to objectively combine metrics when developing stressor specific multimetric indicator

In the context of the European Water Framework Directive (WFD), monitoring programs and related indicators have been developed to assess anthropogenic impacts on various components of aquatic ecosystems. While great precautions are usually taken when selecting and calculating relevant core metrics, little attention is generally paid to the generation of the multimetric indicator, i.e. the combination of the different core metrics. Indeed, most multimetric indicators are generated by simply averaging or summing metrics, without taking into account their sensitivity and their variability. Moreover, few indicators provide a rigorous estimate of the uncertainty of the assessments, while this estimation is essential for managers. In this context, we developed a Bayesian framework to build multimetric indicators aiming at improving those two weaknesses. This framework is based on two phases. First, pressure-impact statistical models are developed to quantify the impact of pressure on various fish metrics. Then the Bayesian theorem is applied to estimate probabilities of being at a certain anthropogenic pressure level from fish observation and pressure-impact models outputs. The Bayesian theorem allows to combine objectively the different core metrics, taking into account their sensitivity and their variability, and to provide rigorous uncertainty quantification, which is especially valuable in the WFD context. The method is applied as illustrative example on transitional French water bodies to demonstrate its relevance, especially in the Water Framework Directive context though the method is generic enough to be applied in various contexts

Comparison of cluster-based and source-attribution methods for estimating transmission risk using large HIV sequence databases

Phylogenetic clustering of HIV sequences from a random sample of patients can reveal epidemiological transmission patterns, but interpretation is hampered by limited theoretical support and statistical properties of clustering analysis remain poorly understood. Alternatively, source attribution methods allow fitting of HIV transmission models and thereby quantify aspects of disease transmission. A simulation study was conducted to assess error rates of clustering methods for detecting transmission risk factors. We modeled HIV epidemics among men having sex with men and generated phylogenies comparable to those that can be obtained from HIV surveillance data in the UK. Clustering and source attribution approaches were applied to evaluate their ability to identify patient attributes as transmission risk factors. We find that commonly used methods show a misleading association between cluster size or odds of clustering and covariates that are correlated with time since infection, regardless of their influence on transmission. Clustering methods usually have higher error rates and lower sensitivity than source attribution method for identifying transmission risk factors. But neither methods provide robust estimates of transmission risk ratios. Source attribution method can alleviate drawbacks from phylogenetic clustering but formal population genetic modeling may be required to estimate quantitative transmission risk factors