715 research outputs found
Image analysis methods for quantifying structural variation in cluster molecular dynamics
Inspired by methods of remote sensing image analysis, we analyze structural
variation in cluster molecular dynamics (MD) simulations through a unique
application of the principal component analysis (PCA) and Pearson Correlation
Coefficient (PCC). The PCA analysis characterizes the geometric shape of the
cluster structure at each time step, yielding a detailed and quantitative
measure of structural stability and variation at finite temperature. Our PCC
analysis captures bond structure variation in MD, which can be used to both
supplement the PCA analysis as well as compare bond patterns between different
cluster sizes. Relying only on atomic position data, without requirement for a
priori structural input, PCA and PCC can be used to analyze both classical and
ab initio MD simulations for any cluster composition or electronic
configuration. Taken together, these statistical tools represent powerful new
techniques for quantitative structural characterization and isomer
identification in cluster MD
Successful percutaneous cholangioscopic extraction of vascular coils that had eroded into the bile duct after liver transplantation
PO-0772: Multi-center validation of a model for prostate tumor delineation using multi-parametric MRI
Outcomes with daptomycin in the treatment of Staphylococcus aureus infections with a range of vancomycin MICs
Staphylococcus aureus suggest the use of alternative agents when vancomycin MIC values are ≥2 mg/L. This study examines the outcome of patients treated with daptomycin for S. aureus infections with documented vancomycin MICs. Patients and methods: All patients with skin, bacteraemia and endocarditis infections due to S. aureus with vancomycin MIC values in CORE 2005–08, a retrospective, multicentre, observational registry, were studied. The outcome (cure, improved, failure or non-evaluable) was the investigator assessment at the end of dapto-mycin therapy. Success was defined as cure or improved. Results: Five hundred and forty-seven clinically evaluable patients were identified with discrete vancomycin MIC values [MIC,2 mg/L: 451 (82%); MIC ≥2 mg/L: 96 (18%)]. The vancomycin MIC groups were well matched for patient characteristics, types of infections, first-line daptomycin use (19%) and prior vancomycin use (58%). Clinical success was reported in 94 % of patients. No differences were detected in the daptomycin success rate by the vancomycin MIC group overall or by the infection type. A multivariate logistic regression also failed to identify vancomycin MIC as a predictor of daptomycin failure. Adverse event (AE) rates were not differ-ent when analysed by MIC group; both groups had 17 % of patients with one AE. Conclusions: In this diverse population, daptomycin was associated with similar outcomes for patients, regard-less of whether the vancomycin MIC was categorized as,2 or ≥2 mg/L. Further studies are warranted
Cryptococcus neoformans Capsular Enlargement and Cellular Gigantism during Galleria mellonella Infection
We have studied infection of Cryptococcus neoformans in the non-vertebrate host Galleria mellonella with particular interest in the morphological response of the yeast. Inoculation of C. neoformans in caterpillars induced a capsule-independent increase in haemocyte density 2 h after infection. C. neoformans manifested a significant increase in capsule size after inoculation into the caterpillar. The magnitude of capsule increase depended on the temperature, being more pronounced at 37°C than at 30°C, which correlated with an increased virulence of the fungus and reduced phagocytosis at 37°C. Capsule enlargement impaired phagocytosis by haemocytes. Incubation of the yeast in G. mellonella extracts also resulted in capsule enlargement, with the polar lipidic fraction having a prominent role in this effect. During infection, the capsule decreased in permeability. A low proportion of the cells (<5%) recovered from caterpillars measured more than 30 µm and were considered giant cells. Giant cells recovered from mice were able to kill the caterpillars in a manner similar to regular cells obtained from in vivo or grown in vitro, establishing their capacity to cause disease. Our results indicate that the morphological transitions exhibited by C. neoformans in mammals also occur in a non-vertebrate host system. The similarities in morphological transitions observed in different animal hosts and in their triggers are consistent with the hypothesis that the cell body and capsular responses represent an adaptation of environmental survival strategies to pathogenesis
Education on tick bite and Lyme borreliosis prevention, aimed at schoolchildren in the Netherlands: comparing the effects of an online educational video game versus a leaflet or no intervention
Public health professionals' perceptions toward provision of health protection in England: a survey of expectations of Primary Care Trusts and Health Protection Units in the delivery of health protection
BACKGROUND: Effective health protection requires systematised responses with clear accountabilities. In England, Primary Care Trusts and the Health Protection Agency both have statutory responsibilities for health protection. A Memorandum of Understanding identifies responsibilities of both parties, but there is a potential lack of clarity about responsibility for specific health protection functions. We aimed to investigate professionals' perceptions of responsibility for different health protection functions, to inform future guidance for, and organisation of, health protection in England. METHODS: We sent a postal questionnaire to all health protection professionals in England from the following groups: (a) Directors of Public Health in Primary Care Trusts; (b) Directors of Health Protection Units within the Health Protection Agency; (c) Directors of Public Health in Strategic Health Authorities and; (d) Regional Directors of the Health Protection Agency RESULTS: The response rate exceeded 70%. Variations in perceptions of who should be, and who is, delivering health protection functions were observed within, and between, the professional groups (a)-(d). Concordance in views of which organisation should, and which does deliver was high (≥90%) for 6 of 18 health protection functions, but much lower (≤80%) for 6 other functions, including managing the implications of a case of meningitis out of hours, of landfill environmental contamination, vaccination in response to mumps outbreaks, nursing home infection control, monitoring sexually transmitted infections and immunisation training for primary care staff. The proportion of respondents reporting that they felt confident most or all of the time in the safe delivery of a health protection function was strongly correlated with the concordance (r = 0.65, P = 0.0038). CONCLUSION: Whilst we studied professionals' perceptions, rather than actual responses to incidents, our study suggests that there are important areas of health protection where consistent understanding of responsibility for delivery is lacking. There are opportunities to clarify the responsibility for health protection in England, perhaps learning from the approaches used for those health protection functions where we found consistent perceptions of accountability
Bioaccumulation of total mercury in the earthworm Eisenia andrei
Earthworms are a major part of the total biomass of soil fauna and play a vital role
in soil maintenance. They process large amounts of plant and soil material and can
accumulate many pollutants that may be present in the soil. Earthworms have been
explored as bioaccumulators for many heavy metal species such as Pb, Cu and Zn but
limited information is available for mercury uptake and bioaccumulation in earth-
worms and very few report on the factors that influence the kinetics of Hg uptake by
earthworms. It is known however that the uptake of Hg is strongly influenced by the
presence of organic matter, hence the influence of ligands are a major factor contribut
-
ing to the kinetics of mercury uptake in biosystems. In this work we have focused on
the uptake of mercury by earthworms (
Eisenia andrei
) in the presence of humic acid
(HA) under varying physical conditions of pH and temperature, done to assess the role
of humic acid in the bioaccumulation of mercury by earthworms from soils. The study
was conducted over a 5-day uptake period and all earthworm samples were analysed
by direct mercury analysis. Mercury distribution profiles as a function of time, bioac-
cumulation factors (BAFs), first order rate constants and body burden constants for
mercury uptake under selected conditions of temperature, pH as well as via the dermal
and gut route were evaluated in one comprehensive approach. The results showed
that the uptake of Hg was influenced by pH, temperature and the presence of HA.
Uptake of Hg
2
+
was improved at low pH and temperature when the earthworms in
soil were in contact with a saturating aqueous phase. The total amount of Hg
2
+
uptake
decreased from 75 to 48
% as a function of pH. For earthworms in dry soil, the uptake
was strongly influenced by the presence of the ligand. Calculated BAF values ranged
from 0.1 to 0.8. Mercury uptake typically followed first order kinetics with rate constants
determined as 0.2 to 1
h
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1
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