1,636 research outputs found
In-plane structure and ordering at liquid sodium surfaces and interfaces from ab initio molecular dynamics
Atoms at liquid metal surfaces are known to form layers parallel to the
surface. We analyze the two-dimensional arrangement of atoms within such layers
at the surface of liquid sodium, using ab initio molecular dynamics (MD)
simulations based on density functional theory. Nearest neighbor distributions
at the surface indicate mostly 5-fold coordination, though there are noticeable
fractions of 4-fold and 6-fold coordinated atoms. Bond angle distributions
suggest a movement toward the angles corresponding to a six-fold coordinated
hexagonal arrangement of the atoms as the temperature is decreased towards the
solidification point. We rationalize these results with a distorted hexagonal
order at the surface, showing a mixture of regions of five and six-fold
coordination. The liquid surface results are compared with classical MD
simulations of the liquid surface, with similar effects appearing, and with ab
initio MD simulations for a model solid-liquid interface, where a pronounced
shift towards hexagonal ordering is observed as the temperature is lowered
Neuropsychological outcomes of children with Optic Pathway Glioma
Optic Pathway Glioma (OPG) is a relatively common brain tumour in childhood; however, there is scarce understanding of neuropsychological sequelae in these survivors. In this study, 12 children with diagnosis of OPG before 6 years of age received a comprehensive standardised assessment of visual perception, general intelligence and academic achievement, using adjustments to visual materials of the tests, to examine the extent of concurrent impairment in these functional domains. Information about vision, clinical and sociodemographic factors were extracted from medical records to assess the associations of neuropsychological outcomes with clinical and socio-demographic factors. Children with OPG exhibited high within-patient variability and moderate group-level impairment compared to test norms. Visual perception was the most impaired domain, while scholastic progression was age-appropriate overall. For cognition, core verbal and visuo-spatial reasoning skills were intact, whereas deficits were found in working memory and processing speed. Visual function was associated with tasks that rely on visual input. Children with OPG are at moderate risk of neuropsychological impairment, especially for visual perception and cognitive proficiency. Future research should elucidate further the relative contribution of vision loss and neurofibromatosis type 1 co-diagnosis within a large sample
Preferences for endovascular (EVAR) or open surgical repair among patients with abdominal aortic aneurysms under surveillance
ObjectivesThere is no evidence about patient preferences for treatment of abdominal aortic aneurysms (AAA) by endovascular aneurysm repair (EVAR) or open surgical repair (OSR). This study examined patient preferences for elective future aneurysm repair and factors that may influence such preferences.MethodsPatients with small AAAs under ultrasound scan surveillance at two United Kingdom (UK) hospitals participated in a semi-structured telephone interview. Features of the two techniques were assessed with regard to their influence on the preferences of participants for EVAR or OSR, using a Likert scale. In addition, participants ranked the relative importance of 14 features against each other.ResultsFifty-six out of 100 eligible participants (56%) completed the semi-structured telephone interview. Of those, 84% (47 patients) said they would prefer a future EVAR repair. Patients who expressed a preference for OSR were significantly younger. Risks of major organ failure and death were most commonly judged as important features in influencing patient preference (Likert scale score 5/5). Risk of death was also most frequently ranked above all other features. Postoperative morbidity and mortality were regarded by patients as more important than the need for surveillance and risk of long-term problems with EVAR. Type of incision and radiation exposure were both given low Likert scale scores of 1/5, and the risk of sexual dysfunction was most frequently ranked as the least important feature of either operation, out of 14 other features.ConclusionWhen presented with detailed information about EVAR and OSR, most patients with small aneurysms would prefer EVAR
Building and Delivering a Successful Dementia Research Portfolio through Collaboration.
Conference poster presented at Clinical Trials Symposium, RD&E 5/11/15.Collaboration between Devon Partnership Trust and Royal Devon & Exeter NHS Foundation Trust
Recommendations for assessing cognitive risks in young children treated for ependymoma for clinical and research protocols: evidence from a systematic literature review
Background: Current treatment approaches for pediatric ependymoma differ between North American and European studies. Post-surgical adjuvant irradiation is used in children aged <36 months in North America, whilst European approaches use chemotherapy to avoid or defer radiotherapy until three years of age, in order to avoid late neurocognitive toxicity. To establish evidence for the effects of cranial radiotherapy in children aged <36 months with ependymoma on neurocognitive outcomes, we conducted a systematic literature review assessing methodological approaches for measuring neurocognitive outcome. Methods: Eight databases were selected to perform an advanced search, retrieval and systematic review of papers describing neurocognitive outcome in children diagnosed with ependymoma who received cranial radiotherapy at <36 months. Results: Limitations of published data permitted descriptive analysis only. Considerable variation in reporting survival rates, techniques and timing of psychometric testing and the results of neurocognitive outcomes was identified. Conclusions: The review identified significant inconsistencies of neurocognitive testing, particularly literacy skills, developmental time points for testing and methods of data reporting. The role of the cerebellum for cognitive development, especially reading, has been inadequately evaluated in published studies. Recommendations are made to improve assessment methods, and time points for testing, so that reports do not fail to identify children who acquire deficits as they mature through childhood and adolescence. We conclude that claims that radiation treatment for ependymoma administered aged <36 months is associated with limited neurocognitive consequences, are not supported by the literature
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The impact of sequencing depth on the inferred taxonomic composition and AMR gene content of metagenomic samples
Shotgun metagenomics is increasingly used to characterise microbial communities, particularly for the investigation of antimicrobial resistance (AMR) in different animal and environmental contexts. There are many different approaches for inferring the taxonomic composition and AMR gene content of complex community samples from shotgun metagenomic data, but there has been little work establishing the optimum sequencing depth, data processing and analysis methods for these samples. In this study we used shotgun metagenomics and sequencing of cultured isolates from the same samples to address these issues. We sampled three potential environmental AMR gene reservoirs (pig caeca, river sediment, effluent) and sequenced samples with shotgun metagenomics at high depth (~ 200 million reads per sample). Alongside this, we cultured single-colony isolates of Enterobacteriaceae from the same samples and used hybrid sequencing (short- and long-reads) to create high- quality assemblies for comparison to the metagenomic data. To automate data processing, we developed an open- source software pipeline, ‘ResPipe’
The Intestinal Microbiota Contributes to the Ability of Helminths to Modulate Allergic Inflammation
We thank Manuel Kulagin for technical help, Pierre Bonnaventure for portal vein blood sampling, Francisco Sepulveda for technical assistance in GS-MS acquisition, and Dorothee Hahne (Metabolomics Australia, University of Western Australia) for human samples SCFA isolation, acquisition, and analysis. We also thank Cristina Cartoni (Phenotyping Unit, EPFL) for Milliplex analysis, Jessica Dessimoz and her team from the Histology Core Facility (EPFL), Miguel Garcia and his team from the Flow Cytometry Core Facility (EPFL), and staff from the EPFL CPG animal house for excellent animal care. The computations were partially performed at the Vital-IT Center for high-performance computing of the SIB Swiss Institute of Bioinformatics (http://www.vital-it.ch). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 310948. Funding for A.W.W. and a subset of the 16S rRNA gene sequencing was provided by the Wellcome Trust (grant number WT 098051). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
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