141 research outputs found
Self-consistent multi-component simulation of plasma turbulence and neutrals in detached conditions
Simulations of high-density deuterium plasmas in a lower single-null magnetic
configuration based on a TCV discharge are presented. We evolve the dynamics of
three charged species (electrons, D and D), interacting with
two neutrals species (D and D) through ionization, charge-exchange,
recombination and molecular dissociation processes. The plasma is modelled by
using the drift-reduced fluid Braginskii equations, while the neutral dynamics
is described by a kinetic model. To control the divertor conditions, a D
puffing is used and the effect of increasing the puffing strength is
investigated. The increase in fuelling leads to an increase of density in the
scrape-off layer and a decrease of the plasma temperature. At the same time,
the particle and heat fluxes to the divertor target decrease and the detachment
of the inner target is observed. The analysis of particle and transport balance
in the divertor volume shows that the decrease of the particle flux is caused
by a decrease of the local neutral ionization together with a decrease of the
parallel velocity, both caused by the lower plasma temperature. The relative
importance of the different collision terms is assessed, showing the crucial
role of molecular interactions, as they are responsible for increasing the
atomic neutral density and temperature, since most of the D neutrals are
produced by molecular activated recombination and D dissociation. The
presence of strong electric fields in high-density plasmas is also shown,
revealing the role of the drift in setting the asymmetry between
the divertor targets. Simulation results are in agreement with experimental
observations of increased density decay length, attributed to a decrease of
parallel transport, together with an increase of plasma blob size and radial
velocity
The mycotoxin phomoxanthone A disturbs the form and function of the inner mitochondrial membrane.
Mitochondria are cellular organelles with crucial functions in the generation and distribution of ATP, the buffering of cytosolic Ca2+ and the initiation of apoptosis. Compounds that interfere with these functions are termed mitochondrial toxins, many of which are derived from microbes, such as antimycin A, oligomycin A, and ionomycin. Here, we identify the mycotoxin phomoxanthone A (PXA), derived from the endophytic fungus Phomopsis longicolla, as a mitochondrial toxin. We show that PXA elicits a strong release of Ca2+ from the mitochondria but not from the ER. In addition, PXA depolarises the mitochondria similarly to protonophoric uncouplers such as CCCP, yet unlike these, it does not increase but rather inhibits cellular respiration and electron transport chain activity. The respiration-dependent mitochondrial network structure rapidly collapses into fragments upon PXA treatment. Surprisingly, this fragmentation is independent from the canonical mitochondrial fission and fusion mediators DRP1 and OPA1, and exclusively affects the inner mitochondrial membrane, leading to cristae disruption, release of pro-apoptotic proteins, and apoptosis. Taken together, our results suggest that PXA is a mitochondrial toxin with a novel mode of action that might prove a useful tool for the study of mitochondrial ion homoeostasis and membrane dynamics
Expectations and satisfaction with antenatal care among pregnant women with a focus on vulnerable groups: a descriptive study in Ghent
U-Compare bio-event meta-service: compatible BioNLP event extraction services
AbstractBackgroundBio-molecular event extraction from literature is recognized as an important task of bio text mining and, as such, many relevant systems have been developed and made available during the last decade. While such systems provide useful services individually, there is a need for a meta-service to enable comparison and ensemble of such services, offering optimal solutions for various purposes.ResultsWe have integrated nine event extraction systems in the U-Compare framework, making them inter-compatible and interoperable with other U-Compare components. The U-Compare event meta-service provides various meta-level features for comparison and ensemble of multiple event extraction systems. Experimental results show that the performance improvements achieved by the ensemble are significant. ConclusionsWhile individual event extraction systems themselves provide useful features for bio text mining, the U-Compare meta-service is expected to improve the accessibility to the individual systems, and to enable meta-level uses over multiple event extraction systems such as comparison and ensemble.This research was partially supported by KAKENHI 18002007 [YK, MM, JDK, SP, TO, JT]; JST PRESTO and KAKENHI 21500130 [YK]; the Academy of Finland and computational resources were provided by CSC -- IT Center for Science Ltd [JB, FG]; the Research Foundation Flanders (FWO) [SVL]; UK Biotechnology and Biological Sciences, Research Council (BBSRC project BB/G013160/1 Automated Biological Event Extraction from the Literature for Drug Discovery) and JISC, National Centre for Text Mining [SA]; the Spanish grant BIO2010-17527 [MN, APM]; NIH Grant U54 DA021519 [AO, DRR]Peer Reviewe
Safety and efficacy of a dapivirine vaginal ring for HIV prevention in women
BACKGROUND
The incidence of human immunodeficiency virus (HIV) infection remains high
among women in sub-Saharan Africa. We evaluated the safety and efficacy of extended
use of a vaginal ring containing dapivirine for the prevention of HIV infection
in 1959 healthy, sexually active women, 18 to 45 years of age, from seven communities
in South Africa and Uganda.
METHODS
In this randomized, double-blind, placebo-controlled, phase 3 trial, we randomly
assigned participants in a 2:1 ratio to receive vaginal rings containing either 25 mg
of dapivirine or placebo. Participants inserted the rings themselves every 4 weeks
for up to 24 months. The primary efficacy end point was the rate of HIV type 1
(HIV-1) seroconversion.
RESULTS
A total of 77 participants in the dapivirine group underwent HIV-1 seroconversion
during 1888 person-years of follow-up (4.1 seroconversions per 100 person-years),
as compared with 56 in the placebo group who underwent HIV-1 seroconversion
during 917 person-years of follow-up (6.1 seroconversions per 100 person-years).
The incidence of HIV-1 infection was 31% lower in the dapivirine group than in
the placebo group (hazard ratio, 0.69; 95% confidence interval [CI], 0.49 to 0.99; P = 0.04). There was no significant difference in efficacy of the dapivirine ring
among women older than 21 years of age (hazard ratio for infection, 0.63; 95% CI,
0.41 to 0.97) and those 21 years of age or younger (hazard ratio, 0.85; 95% CI, 0.45
to 1.60; P = 0.43 for treatment-by-age interaction). Among participants with HIV-1
infection, nonnucleoside reverse-transcriptase inhibitor resistance mutations were
detected in 14 of 77 participants in the dapivirine group (18.2%) and in 9 of 56
(16.1%) in the placebo group. Serious adverse events occurred more often in the
dapivirine group (in 38 participants [2.9%]) than in the placebo group (in 6 [0.9%]).
However, no clear pattern was identified.
CONCLUSIONS
Among women in sub-Saharan Africa, the dapivirine ring was not associated with
any safety concerns and was associated with a rate of acquisition of HIV-1 infection
that was lower than the rate with placebo.Supported by the International Partnership for Microbicides
(a not-for-profit product-development partnership), which receives
support from the Bill and Melinda Gates Foundation,
Irish Aid, the Ministry of Foreign Affairs of Denmark, the Ministry
of Foreign Affairs of the Netherlands, the Norwegian
Agency for Development Cooperation, the U.K. Department for
International Development, the American people through the
U.S. Agency for International Development, and the President’s
Emergency Plan for AIDS Relief.http://www.nejm.org2017-06-01am2017Family Medicin
Quality-Controlled Small-Scale Production of a Well-Defined Bacteriophage Cocktail for Use in Human Clinical Trials
We describe the small-scale, laboratory-based, production and quality control of a cocktail, consisting of exclusively lytic bacteriophages, designed for the treatment of Pseudomonas aeruginosa and Staphylococcus aureus infections in burn wound patients. Based on succesive selection rounds three bacteriophages were retained from an initial pool of 82 P. aeruginosa and 8 S. aureus bacteriophages, specific for prevalent P. aeruginosa and S. aureus strains in the Burn Centre of the Queen Astrid Military Hospital in Brussels, Belgium. This cocktail, consisting of P. aeruginosa phages 14/1 (Myoviridae) and PNM (Podoviridae) and S. aureus phage ISP (Myoviridae) was produced and purified of endotoxin. Quality control included Stability (shelf life), determination of pyrogenicity, sterility and cytotoxicity, confirmation of the absence of temperate bacteriophages and transmission electron microscopy-based confirmation of the presence of the expected virion morphologic particles as well as of their specific interaction with the target bacteria. Bacteriophage genome and proteome analysis confirmed the lytic nature of the bacteriophages, the absence of toxin-coding genes and showed that the selected phages 14/1, PNM and ISP are close relatives of respectively F8, φKMV and phage G1. The bacteriophage cocktail is currently being evaluated in a pilot clinical study cleared by a leading Medical Ethical Committee
Factors associated with spontaneous stone passage in a contemporary cohort of patients presenting with acute ureteric colic. Results from the MIMIC Study (A Multi-centre cohort study evaluating the role of Inflammatory Markers in patients presenting with acute ureteric Colic)
Objectives
There is conflicting data on the role of white blood cell count (WBC) and other inflammatory markers in spontaneous stone passage in patients with acute ureteric colic. The aim of the study was to assess the relationship of WBC and other routinely collected inflammatory and clinical markers including stone size, stone position and Medically Expulsive Therapy use (MET) with spontaneous stone passage (SSP) in a large contemporary cohort of patients with acute ureteric colic.
Subjects and Methods
Multi‐centre retrospective cohort study coordinated by the British Urology Researchers in Surgical Training (BURST) Research Collaborative at 71 secondary care hospitals across 4 countries (United Kingdom, Republic of Ireland, Australia and New Zealand). 4170 patients presented with acute ureteric colic and a computer tomography confirmed single ureteric stone. Our primary outcome measure was SSP as defined by the absence of need for intervention to assist stone passage. Multivariable mixed effects logistic regression was used to explore the relationship between key patient factors and SSP.
Results
2518 patients were discharged with conservative management and had further follow up with a SSP rate of 74% (n = 1874/2518). Sepsis after discharge with conservative management was reported in 0.6% (n = 16/2518). On multivariable analysis neither WBC, Neutrophils or CRP were seen to predict SSP, with an adjusted OR of 0.97 [95% CI 0.91 to 1.04, p = 0.38], 1.06 [95% CI 0.99 to 1.13, p = 0.1] and 1.00 [95% CI 0.99 to 1.00, p = 0.17], respectively. Medical expulsive therapy (MET) also did not predict SSP [adjusted OR 1.11 [95% CI 0.76 to 1.61]). However, stone size and stone position were significant predictors. SSP for stones 7mm. For stones in the upper ureter the SSP rate was 52% [95% CI 48 to 56], middle ureter was 70% [95% CI 64 to 76], and lower ureter was 83% [95% CI 81 to 85].
Conclusion
In contrast to the previously published literature, we found that in patients with acute ureteric colic who are discharged with initial conservative management, neither WBC, Neutrophil count or CRP help determine the likelihood of spontaneous stone passage. We also found no overall benefit from the use of MET. Stone size and position are important predictors and our findings represent the most comprehensive stone passage rates for each mm increase in stone size from a large contemporary cohort adjusting for key potential confounders. We anticipate that these data will aid clinicians managing patients with acute ureteric colic and help guide management decisions and the need for intervention
Priorities and strategies for improving disabled women's access to maternity services when they are affected by domestic abuse:a multi-method study using concept maps
BACKGROUND: Domestic abuse is a significant public health issue. It occurs more frequently among disabled women than those without a disability and evidence suggests that a great deal of domestic abuse begins or worsens during pregnancy. All women and their infants are entitled to equal access to high quality maternity care. However, research has shown that disabled women who experience domestic abuse face numerous barriers to accessing care. The aim of the study was to identify the priority areas for improving access to maternity services for this group of women; develop strategies for improved access and utilisation; and explore the feasibility of implementing the identified strategies. METHODS: This multi-method study was the third and final part of a larger study conducted in the UK between 2012 and 2014. The study used a modified concept mapping approach and was theoretically underpinned by Andersen’s model of healthcare use. Seven focus group interviews were conducted with a range of maternity care professionals (n = 45), incorporating quantitative and qualitative components. Participants ranked perceived barriers to women’s access and utilisation of maternity services in order of priority using a 5-point Likert scale. Quantitative data exploration used descriptive and non-parametric analyses. In the qualitative component of each focus group, participants discussed the barriers and identified potential improvement strategies (and feasibility of implementing these). Qualitative data were analysed inductively using a framework analysis approach. RESULTS: The three most highly ranked barriers to women’s access and utilisation of maternity services identified in the quantitative component were: 1) staff being unaware and not asking about domestic abuse and disability; 2) the impact of domestic abuse on women; 3) women’s fear of disclosure. The top two priority strategies were: providing information about domestic abuse to all women and promoting non-judgemental staff attitude. These were also considered very feasible. The qualitative analysis identified a range of psychosocial and environmental barriers experienced by this group of women in accessing maternity care. Congruent with the quantitative results, the main themes were lack of awareness and fear of disclosure. Key strategies were identified as demystifying disclosure and creating physical spaces to facilitate disclosure. CONCLUSIONS: The study supports findings of previous research regarding the barriers that women face in accessing and utilising maternity services, particularly regarding the issue of disclosure. But the study provides new evidence on the perceived importance and feasibility of strategies to address such barriers. This is an important step in ensuring practice-based acceptability and ease with which improvement strategies might be implemented in maternity care settings
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