767 research outputs found
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
Trends and predictors of linkage to HIV outpatient care following diagnosis in the era of expanded testing in England, Wales and Northern Ireland: Results of a national cohort study
OBJECTIVES: We explore trends in linkage to HIV care following diagnosis and investigate the impact of diagnosis setting on linkage in the era of expanded testing. METHODS: All adults (aged ≥ 15 years) diagnosed with HIV between 2005 and 2014 in England, Wales and Northern Ireland (EW&NI) were followed up until the end of 2017. People who died within 1 month of diagnosis were excluded (n = 1009). Trends in linkage to outpatient care (time to first CD4 count) were examined by sub-population and diagnosis setting. Logistic regression identified predictors of delayed linkage of > 1 month, > 3 months and > 1 year post-diagnosis (2012-2014). RESULTS: Overall, 97% (60 250/62 079) of people linked to care; linkage ≤ 1 month was 75% (44 291/59 312), ≤ 3 months was 88% (52 460) and ≤ 1 year was 95% (56 319). Median time to link declined from 15 days [interquartile range (IQR): 4-43] in 2005 to 6 (IQR: 0-20) days in 2014 (similar across sub-populations/diagnosis settings). In multivariable analysis, delayed linkage to care was associated with acquiring HIV through injecting drug use, heterosexual contact or other routes compared with sex between men (> 1 month/3 months/1 year), being diagnosed in earlier years (> 1 month/3 months/1 year) and having a first CD4 ≥ 200 cells/μL (> 3 months/1 year). Diagnosis outside of sexual health clinics, antenatal services and infectious disease units predicted delays of > 1 month. By 3 months, only diagnosis in 'other' settings (prisons, drug services, community and other medical settings) was significant. CONCLUSIONS: Linkage to care following HIV diagnosis is relatively timely in EW&NI. However, non-traditional testing venues should have well-defined referral pathways established to facilitate access to care and treatment
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
Diagnosis delays in the UK according to pre- or post-migration acquisition of HIV
Objectives:
To evaluate whether infection occurred pre- or post-migration and the associated diagnosis delay in migrants diagnosed with HIV in the UK.
Design:
We analysed a cohort of individuals diagnosed with HIV in the UK in 2014–2016 born in Africa or elsewhere in Europe. Inclusion criteria were arrival within 15 years before diagnosis, availability of HIV pol sequence and viral subtype shared by at least 10 individuals.
Methods:
We examined phylogenies for evidence of infection after entry into the UK and incorporated this information into a Bayesian analysis of timing of infection using biomarkers of CD4+ cell count, avidity assays, proportion of ambiguous nucleotides in viral sequences and last negative test dates where available.
Results:
1256 individuals were included. The final model indicated that HIV was acquired post-migration for most men who have sex with men (MSM) born in Europe (posterior expectation 65%, 95% credibility interval 64%-67%) or Africa (65%, 62%-69%), whereas a minority (20%-30%) of men and women with heterosexual transmission acquired HIV post-migration. Estimated diagnosis delays were lower for MSM than for those with heterosexual transmission, and were lower for those with post-migration infection across all subgroups. For MSM acquiring HIV post-migration the estimated mean time to diagnosis was 5 years for all subgroups.
Conclusions:
Acquisition of HIV post-migration is common, particularly among MSM calling for prevention efforts aimed at migrant communities. Delays in diagnosis reinforce the need for targeted testing initiatives
Where do we diagnose HIV infection? Monitoring new diagnoses made in nontraditional settings in England, Wales and Northern Ireland.
OBJECTIVES: The objectives of the study were to describe 10-year trends in HIV diagnosis setting and to explore predictors of being diagnosed outside a sexual health clinic (SHC). METHODS: Analyses of national HIV surveillance data were restricted to adults (aged ≥ 15 years) diagnosed in 2005-2014 in England, Wales and Northern Ireland. Logistic regression identified factors associated with diagnosis outside an SHC (2011-2014). RESULTS: Between 2005 and 2014, 63 599 adults were newly diagnosed with HIV infection; 83% had a diagnosis setting reported. Most people were diagnosed in SHCs (69%) followed by: medical admissions/accident and emergency (A&E; 8.6%), general practice (6.4%), antenatal services (5.5%), out-patient services (3.6%), infectious disease units (2.7%) and other settings (4.0%). The proportion of people diagnosed outside SHCs increased from 2005 to 2014, overall (from 27% to 32%, respectively) and among men who have sex with men (MSM) (from 14% to 21%) and black African men (from 25% to 37%) and women (from 39% to 52%) (all trend P < 0.001). Median CD4 increased across all settings, but was highest in SHCs (384 cells/μL) and lowest in medical admissions/A&E (94 cells/μL). Predictors of being diagnosed outside SHCs included: acquiring HIV through heterosexual contact [adjusted odds ratio (aOR) 1.99; 95% confidence interval (CI) 1.81-2.18] or injecting drug use (aOR: 3.28; 95% CI: 2.56-4.19; reference: MSM), being diagnosed late (< 350 cells/μL) (aOR: 2.55; 95% CI: 2.36-2.74; reference: diagnosed promptly) and being of older age at diagnosis (35-49 years: aOR: 1.60; 95% CI: 1.39-1.83; ≥ 50 years: aOR: 2.48; 95% CI: 2.13-2.88; reference: 15-24 years). CONCLUSIONS: The proportion of HIV diagnoses made outside SHCs has increased over the past decade in line with evolving HIV testing guidelines. However, the rate of late diagnosis remains high, indicating that further expansion of testing is necessary, as many people may have had missed opportunities for earlier diagnosis
Obesogenic Lifestyle and Its Influence on Adiposity in Children and Adolescents, Evidence from Mexico
Overweight (OW) and obesity (OB) during childhood/adolescence are major public health problems in Mexico. Several obesogenic lifestyle (OL) risk factors have been identified, but the burden and consequences of them in Mexican children/adolescents remain unclear. The objective of this study was to estimate the prevalence of OL components and describe their relationships with adiposity, and OW/OB. A population-based cross-sectional study of Mexican children/adolescents with nutritional assessment, data collection on daily habits and adiposity as fat-mass index (FMI) by dual-energy X-ray absorptiometry was performed. Individual OL-components: "inactivity," "excessive screen time," "insufficient sleep," "unhealthy-diet", were defined according to non-adherence to previously published healthy recommendations. RESULTS: 1449 subjects were assessed between March 2015 to April 2018. Sixteen percent of subjects had all four OL-components, 40% had three, 35% had two, 9% had one, and 0.5% had none. A cumulative OL score showed a significant dose-response effect with FMI. The combination of inactivity, excessive screen time, and insufficient sleep showed the highest risk association to OW/OB and higher values of FMI. CONCLUSIONS: The prevalence of OL-components was extremely high and associated with increased adiposity and OW/OB. Several interventions are needed to revert this major public health threat
Eustatic change modulates exhumation in the Japanese Alps
The exhumation of bedrock is controlled by the interplay between tectonics, surface processes, and climate. The highest exhumation rates of centimeters per year are recorded in zones of highly active tectonic convergence such as the Southern Alps of New Zealand or the Himalayan syntaxes, where high rock uplift rates combine with very active surface processes. Using a combination of different thermochronometric systems including trapped-charge thermochronometry, we show that such rates also occur in the Hida Mountain Range, Japanese Alps. Our results imply that centimeter per year rates of exhumation are more common than previously thought. Our thermochronometry data allow the development of time series of exhumation rate changes at the time scale of glacial-interglacial cycles, which show a fourfold increase in baseline rates to rates of ~10 mm/yr within the past ~65 k.y. This increase in exhumation rate is likely explained by knickpoint propagation due to a combination of very high precipitation rates, climatic change, sea-level fall, range-front faulting, and moderate rock uplift. Our data resolve centimeter-scale sub-Quaternary exhumation rate changes, which show that in regions with horizontal convergence, coupling between climate, surface processes, and tectonics can exert a significant and rapid effect on rates of exhumatio
Remote Internal Wave Forcing of Regional Ocean Simulations Near the U.S. West Coast
Low mode internal waves are able to propagate across ocean basins and modulate ocean dynamics thousands of kilometers away from their generation sites. In this study, the impact of remotely generated internal waves on the internal wave energetics near the U.S. West Coast is investigated with realistically forced regional ocean simulations. At the open boundaries, we impose high-frequency oceanic state variables obtained from a global ocean simulation with realistic atmospheric and astronomical tidal forcing. We use the Discrete Fourier Transform (DFT) technique in separating ingoing and outgoing internal tide energy fluxes at the open boundaries in order to quantify internal tide reflections. Although internal tide reflections are reduced with increasing sponge viscosity and/or sponge layer width, reflection coefficients (λ) can be as high as 73%. In the presence of remote internal waves, the model variance and spatial correlations become more in agreement with both mooring and altimetry datasets. The results confirm that an improved internal wave continuum can be achieved in regional models with remote internal wave forcing at the open boundaries. However, care should be taken to avoid excessive reflections of internal waves from the interior at these boundaries
An Oscillating MinD Protein Determines the Cellular Positioning of the Motility Machinery in Archaea.
MinD proteins are well studied in rod-shaped bacteria such as E. coli, where they display self-organized pole-to-pole oscillations that are important for correct positioning of the Z-ring at mid-cell for cell division. Archaea also encode proteins belonging to the MinD family, but their functions are unknown. MinD homologous proteins were found to be widespread in Euryarchaeota and form a sister group to the bacterial MinD family, distinct from the ParA and other related ATPase families. We aimed to identify the function of four archaeal MinD proteins in the model archaeon Haloferax volcanii. Deletion of the minD genes did not cause cell division or size defects, and the Z-ring was still correctly positioned. Instead, one of the deletions (ΔminD4) reduced swimming motility and hampered the correct formation of motility machinery at the cell poles. In ΔminD4 cells, there is reduced formation of the motility structure and chemosensory arrays, which are essential for signal transduction. In bacteria, several members of the ParA family can position the motility structure and chemosensory arrays via binding to a landmark protein, and consequently these proteins do not oscillate along the cell axis. However, GFP-MinD4 displayed pole-to-pole oscillation and formed polar patches or foci in H. volcanii. The MinD4 membrane-targeting sequence (MTS), homologous to the bacterial MinD MTS, was essential for the oscillation. Surprisingly, mutant MinD4 proteins failed to form polar patches. Thus, MinD4 from H. volcanii combines traits of different bacterial ParA/MinD proteins
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