486 research outputs found
Multiple foil lunar environmental analyser (FLEA package) for the evaluation of meteoroid primary impact penetration, radiant, velocity and composition, meteoroid impact ejecta and comminution products, solar wind composition, medium energy solar flare composition, solar wind sputter rate, meteoroid bumper efficiency
The conception of a multiple thin foil sensor has been investigated and is suggested as a very valuable tool for the accumulation of data over long exposure periods on the lunar surface. Data will lead to the evaluation of specific parameters of the meteor environment, of the solar wind spectrum and of the overall environmental erosion rates from both impact and sputtering.by J.A.M. McDonnell and Otto E. Berg.Summary -- Introduction -- Proposal -- Scientific background -- Environmental stability of FLEA system -- Data evaluation -- Support details and personne
Multispectral lensless digital holographic microscope: imaging MCF-7 and MDA-MB-231 cancer cell cultures
Digital holography is the process where an object’s phase and amplitude information is retrieved from intensity images
obtained using a digital camera (e.g. CCD or CMOS sensor). In-line digital holographic techniques offer full use of the
recording device’s sampling bandwidth, unlike off-axis holography where object information is not modulated onto
carrier fringes. Reconstructed images are obscured by the linear superposition of the unwanted, out of focus, twin
images. In addition to this, speckle noise degrades overall quality of the reconstructed images. The speckle effect is a
phenomenon of laser sources used in digital holographic systems. Minimizing the effects due to speckle noise, removal
of the twin image and using the full sampling bandwidth of the capture device aids overall reconstructed image quality.
Such improvements applied to digital holography can benefit applications such as holographic microscopy where the
reconstructed images are obscured with twin image information. Overcoming such problems allows greater flexibility in
current image processing techniques, which can be applied to segmenting biological cells (e.g. MCF-7 and MDA-MB-
231) to determine their overall cell density and viability. This could potentially be used to distinguish between apoptotic
and necrotic cells in large scale mammalian cell processes, currently the system of choice, within the biopharmaceutical
industry
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Quantitative analysis of the ACL and PCL using T1rho and T2 relaxation time mapping: an exploratory, cross-sectional comparison between OA and healthy control knees.
BACKGROUND: Quantitative magnetic resonance imaging (MRI) methods such as T1rho and T2 mapping are sensitive to changes in tissue composition, however their use in cruciate ligament assessment has been limited to studies of asymptomatic populations or patients with posterior cruciate ligament tears only. The aim of this preliminary study was to compare T1rho and T2 relaxation times of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) between subjects with mild-to-moderate knee osteoarthritis (OA) and healthy controls. METHODS: A single knee of 15 patients with mild-to-moderate knee OA (Kellgren-Lawrence grades 2-3) and of 6 age-matched controls was imaged using a 3.0 T MRI. Three-dimensional (3D) fat-saturated spoiled gradient recalled-echo images were acquired for morphological assessment and T1ρ- and T2-prepared pseudo-steady-state 3D fast spin echo images for compositional assessment of the cruciate ligaments. Manual segmentation of whole ACL and PCL, as well as proximal / middle / distal thirds of both ligaments was carried out by two readers using ITK-SNAP and mean relaxation times were recorded. Variation between thirds of the ligament were assessed using repeated measures ANOVAs and differences in these variations between groups using a Kruskal-Wallis test. Inter- and intra-rater reliability were assessed using intraclass correlation coefficients (ICCs). RESULTS: In OA knees, both T1rho and T2 values were significantly higher in the distal ACL when compared to the rest of the ligament with the greatest differences in T1rho (e.g. distal mean = 54.5 ms, proximal = 47.0 ms, p < 0.001). The variation of T2 values within the PCL was lower in OA knees (OA: distal vs middle vs proximal mean = 28.5 ms vs 29.1 ms vs 28.7 ms, p = 0.748; Control: distal vs middle vs proximal mean = 26.4 ms vs 32.7 ms vs 33.3 ms, p = 0.009). ICCs were excellent for the majority of variables. CONCLUSION: T1rho and T2 mapping of the cruciate ligaments is feasible and reliable. Changes within ligaments associated with OA may not be homogeneous. This study is an important step forward in developing a non-invasive, radiological biomarker to assess the ligaments in diseased human populations in-vivo.Declarations
Ethics approval and consent to participate
This study was approved by the East of England Cambridge Central Research Ethics Committee and written informed consent was given by all subjects included in the study. All methods were carried out in accordance with relevant guidelines and regulations.
Consent for publication
Not Applicable
Availability of data and materials
The datasets generated and analysed during the current study are not publicly available due to unattained permission from participants and research ethics committee but could be made available from JWM (email: [email protected]).
Competing interests
JWM, DAK and JDK acknowledge funding support from GlaxoSmithKline for their studentships and fellowships, respectively.
JWM is an employee of AstraZeneca.
CDSR, VAC and SMM have no competing interests to declare.
Acknowledgements
The Addenbrooke's Hospital Magnetic Resonance Imaging and Spectroscopy (MRIS) staff are thanked for their help with arranging and conducting the study MRI examinations. We also acknowledge the support of the Addenbrooke's Charitable Trust and the National Institute for Health Research Cambridge Biomedical Research Centre. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.
Funding
The study was funded by an Experimental Medicine Initiative PhD studentship from the University of Cambridge [grant number RG81329] and by GlaxoSmithKline [grant number RG87552].
Authors' contributions
Writing of original draft manuscript: CDSR. Study design and coordination: CDSR, JWM, JDK and SMM. Data acquisition: JWM and JDK. Data curation, analysis and interpretation: CDSR, JWM, VAC, JDK, DAK and SMM. Statistical analysis: CDSR and JWM. Review and editing of manuscript: JWM, VAC, JDK, DAK and SMM. All authors read and approved the final manuscript
Electronic Structure of Iron Porphyrin Adsorbed to the Pt(111) Surface
Systematic density functional theory calculations that treat the strong on-site 3d electron−electron interactions on iron via a Hubbard Ueff = 3.0 eV and the van der Waals (vdW) interactions between the substrate and adsorbate within the vdW-DF framework are employed to study the adsorption of the iron porphyrin (FeP) molecule to the Pt(111) surface. The more accurate vdW-DF-optPBE and vdW-DF-optB88 functionals found the same binding site to be the most stable and yielded binding energies that were within ∼20% of each other, whereas the binding energies computed with the vdW-DF-revPBE functional were substantially weaker. This work highlights the importance of vdW interactions for organometallic molecules chemisorbed to transition metal surfaces. The stability of the binding sites was found to depend upon the number of Fe−Pt and C−Pt bonds that were formed. Whereas in the gas phase the most stable spin state of FeP is the intermediate spin S = 1 state, the high spin S = 2 state is preferred for the FeP−Pt(111) system on the binding sites considered herein. The spin switch results from the elongation of the Fe−N bonds that occur upon adsorption
Patient-centred outcomes for prehospital trauma trials: A systematic review and patient involvement exercise
Introduction
Outcome measures are used in clinical trials to determine efficacy of interventions. We aimed to determine which outcome measures in prehospital major trauma trials have been reported in the literature, and which of these are most patient-centred.
Methods
A systematic review identified outcomes reported in prehospital clinical trials of major trauma patients. A search was undertaken using Medline, Embase, clinicaltrials.gov, Web of Science and Google Scholar. Data were summarised by dividing outcomes into common themes which were presented to a Patient and Public Involvement group consisting of trauma survivors and their relatives. This group ranked the categories of outcomes in order of most importance, and agreed consensus statements regarding these outcome measures.
Results
There were 27 eligible studies, including 9,537 patients. Outcome measures were divided into nine categories: quality of life; length of stay; mortality/survival; physiological parameters; fluid/blood product requirements; complications; health economics; safety and feasibility; and intervention success. Of these, mortality/survival was the most commonly reported category, but over multiple timescales. The Patient and Public Involvement group agreed that the most important category was quality of life, and that mortality/survival should only be reported if concurrently reported with longer term quality of life. Length of stay and health economics were not considered important.
Conclusions
Outcome measures in prehospital clinical trials in major trauma have been heterogeneous, inconsistent, and not necessarily patient-centred. Trauma survivors considered quality of life and mortality most important when combined. Consensus is required for consistent, patient-centred, outcome measures in order to investigate interventions of meaningful impact to patients
Interplay between Affinity and Valency in Effector Cell Degranulation: A Model System with Polcalcin Allergens and Human Patient-Derived IgE Antibodies.
This is the accepted, uncopyedited version of the manuscript. The definitive version was published in The Journal of Immunology August 28, 2019, ji1900509; DOI: https://doi.org/10.4049/jimmunol.1900509Originally published in The Journal of Immunology. Bucaite G, Kang-Pettinger T, Moreira J, et al. Interplay between Affinity and Valency in Effector Cell Degranulation: A Model System with Polcalcin Allergens and Human Patient-Derived IgE Antibodies. J Immunol. 2019;203(7):1693-1700. doi:10.4049/jimmunol.1900509 The American Association of Immunologists, Inc.An allergic reaction is rapidly generated when allergens bind and cross-link IgE bound to its receptor FcεRI on effector cells, resulting in cell degranulation and release of proinflammatory mediators. The extent of effector cell activation is linked to allergen affinity, oligomeric state, valency, and spacing of IgE-binding epitopes on the allergen. Whereas most of these observations come from studies using synthetic allergens, in this study we have used Timothy grass pollen allergen Phl p 7 and birch pollen allergen Bet v 4 to study these effects. Despite the high homology of these polcalcin family allergens, Phl p 7 and Bet v 4 display different binding characteristics toward two human patient-derived polcalcin-specific IgE Abs. We have used native polcalcin dimers and engineered multimeric allergens to test the effects of affinity and oligomeric state on IgE binding and effector cell activation. Our results indicate that polcalcin multimers are required to stimulate high levels of effector cell degranulation when using the humanized RBL-SX38 cell model and that multivalency can overcome the need for high-affinity interactions.This work was supported by Medical Research Council Grant G1100090. G.B. was supported by a studentship from the King’s Bioscience Institute and by the Guy’s and St. Thomas’ Charity Prize Ph.D. Program in Biomedical and Translational Science. We acknowledge the support of the Centre for Biomolecular Spectroscopy, King’s College London, established with a Capital Award from the Wellcome Trust (Grant 085944)
The SCottish Alcoholic Liver disease Evaluation: a population-level matched cohort study of hospital-based costs, 1991-2011
Studies assessing the costs of alcoholic liver disease are lacking. We aimed to calculate the costs of hospitalisations before and after diagnosis compared to population controls matched by age, sex and socio-economic deprivation. We aimed to use population level data to identify a cohort of individuals hospitalised for the first time with alcoholic liver disease in Scotland between 1991 and 2011.Incident cases were classified by disease severity, sex, age group, socio-economic deprivation and year of index admission. 5 matched controls for every incident case were identified from the Scottish population level primary care database.
Hospital costs were calculated for both cases and controls using length of stay from morbidity records and hospital-specific daily rates by specialty. Remaining lifetime costs were estimated using parametric survival models and predicted annual costs. 35,208 incident alcoholic liver disease hospitalisations were identified. Mean annual hospital costs for cases were 2.3 times that of controls pre diagnosis (£804 higher) and 10.2 times (£12,774 higher) post diagnosis. Mean incident admission cost was £6,663. Remaining lifetime cost for a male, 50-59 years old, living in the most deprived area diagnosed with acoholic liver disease was estimated to be £65,999 higher than the matched controls (£12,474 for 7.43 years remaining life compared to £1,224 for 21.8 years). In Scotland, alcoholic liver disease diagnosis is associated with significant increases in admissions to hospital both before and after diagnosis.
Our results provide robust population level estimates of costs of alcoholic liver disease for the purposes of health-care delivery, planning and future cost-effectiveness analyses
Bronchiectasis Rheumatoid Overlap Syndrome Is an Independent Risk Factor for Mortality in Patients With Bronchiectasis:A Multicenter Cohort Study
BACKGROUND: This study assessed if bronchiectasis (BR) and rheumatoid arthritis (RA), when manifesting as an overlap syndrome (BROS), were associated with worse outcomes than other BR etiologies applying the Bronchiectasis Severity Index (BSI).
METHODS: Data were collected from the BSI databases of 1,716 adult patients with BR across six centers: Edinburgh, United Kingdom (608 patients); Dundee, United Kingdom (n = 286); Leuven, Belgium (n = 253); Monza, Italy (n = 201); Galway, Ireland (n = 242); and Newcastle, United Kingdom (n = 126). Patients were categorized as having BROS (those with RA and BR without interstitial lung disease), idiopathic BR, bronchiectasis-COPD overlap syndrome (BCOS), and "other" BR etiologies. Mortality rates, hospitalization, and exacerbation frequency were recorded.
RESULTS: A total of 147 patients with BROS (8.5% of the cohort) were identified. There was a statistically significant relationship between BROS and mortality, although this relationship was not associated with higher rates of BR exacerbations or BR-related hospitalizations. The mortality rate over a mean of 48 months was 9.3% for idiopathic BR, 8.6% in patients with other causes of BR, 18% for RA, and 28.5% for BCOS. Mortality was statistically higher in patients with BROS and BCOS compared with those with all other etiologies. The BSI scores were statistically but not clinically significantly higher in those with BROS compared with those with idiopathic BR (BSI mean, 7.7 vs 7.1, respectively; P < .05). Patients with BCOS had significantly higher BSI scores (mean, 10.4), Pseudomonas aeruginosa colonization rates (24%), and previous hospitalization rates (58%).
CONCLUSIONS: Both the BROS and BCOS groups have an excess of mortality. The mechanisms for this finding may be complex, but these data emphasize that these subgroups require additional study to understand this excess mortality
Ontogeny of Human IgE-expressing B Cells and Plasma Cells
BACKGROUND: IgE‐expressing (IgE(+)) plasma cells (PCs) provide a continuous source of allergen‐specific IgE that is central to allergic responses. The extreme sparsity of IgE(+) cells in vivo has confined their study almost entirely to mouse models. OBJECTIVE: To characterize the development pathway of human IgE(+) PCs and to determine the ontogeny of human IgE(+) PCs. METHODS: To generate human IgE(+) cells, we cultured tonsil B cells with IL‐4 and anti‐CD40. Using FACS and RT‐PCR, we examined the phenotype of generated IgE(+) cells, the capacity of tonsil B‐cell subsets to generate IgE(+) PCs and the class switching pathways involved. RESULTS: We have identified three phenotypic stages of IgE(+) PC development pathway, namely (i) IgE(+)germinal centre (GC)‐like B cells, (ii) IgE(+) PC‐like ‘plasmablasts’ and (iii) IgE(+) PCs. The same phenotypic stages were also observed for IgG1(+) cells. Total tonsil B cells give rise to IgE(+) PCs by direct and sequential switching, whereas the isolated GC B‐cell fraction, the main source of IgE(+) PCs, generates IgE(+) PCs by sequential switching. PC differentiation of IgE(+) cells is accompanied by the down‐regulation of surface expression of the short form of membrane IgE (mIgE(S)), which is homologous to mouse mIgE, and the up‐regulation of the long form of mIgE (mIgE(L)), which is associated with an enhanced B‐cell survival and expressed in humans, but not in mice. CONCLUSION: Generation of IgE(+) PCs from tonsil GC B cells occurs mainly via sequential switching from IgG. The mIgE(L)/mIgE(S) ratio may be implicated in survival of IgE(+) B cells during PC differentiation and allergic disease
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