Search

Background: Intravenous recombinant tissue plasminogen activator (IV rtPA) is a recommended thrombolytic for the treatment of acute ischemic stroke that has shown to improve outcomes in various trials, but its cost-utility within varying time windows has not been systematically reviewed. Method: A systematic review was conducted using 2 reviewers and 1 adjudicator. Search strategies were implemented in PUBMED/MEDLINE, EMBASE, Web of Science, and Cochrane Review. Forms and data were managed through RedCap. Studies that met specific inclusion criteria, such as authors citing the time window and analytic horizon they investigated, and specifying the type of model they implemented, were further assessed for cost-utility benefit. Results: Of the 385 results from the implemented search strategy, 18 studies met inclusion criteria, with 94% agreement between reviewers. Eleven studies looked at the time window within 3 hours of stroke symptom onset, 3 looked between 3 to 4.5 hours, 3 looked within 4.5 hours of onset, and 1 looked within 6 hours of onset. All but 1 study with an analytic horizon of 1 year looking at a 0-3 hour time window showed that that IV rtPA was either dominant or cost-effective at a willingness to pay of $50,000/QALY. Conclusion: IV rtPA shows to be cost-effective across a variety of assumptions, both at a national and international level. The analytic horizon and time window do significantly impact the cost-effectiveness of IV rtPA, but even at later time windows, the IV rtPA shows to be cost-effective relative to standard treatment and care.

The calculation of neutron reflectivity from raw time-of-flight data including instrumental corrections and an improved resolution calculation is presented. The theoretical calculations are compared with experimental data measured on the vertical sample plane reflectometer D17 and the horizontal sample plane reflectometer FIGARO at the Institut Laue–Langevin (ILL), Grenoble, France. This article comprises the mathematical body of the time-of-flight reflectivity data-reduction software COSMOS which is used on D17 and FIGARO.

International audience; In this study, we report on recent neutron inelastic scattering experiments performed at the Institut Laue-Langevin (ILL) for H2O and D2O. The measured dynamic structure factors S(q, ω) have been reduced, normalised and transformed into the S(α, β) formalism, where α and β stand for the unit-less momentum and energy transfers, respectively. The measurements were complemented with molecular dynamics simulations. After processing with NJOY, new water neutron scattering cross-sections have been generated for use with e.g. the Monte Carlo N-Particle (MCNP) software in view to improve the accuracy of the nuclear facility models. As an example, we present improved accuracy calculations for the safety rod insertion impact on the criticality factor keff for the ILL high flux research reactor. © 2014 © 2014 Atomic Energy Society of Japan. All rights reserved.

The MDANSE software—Molecular Dynamics Analysis of Neutron Scattering Experiments—is presented. It is an interactive application for postprocessing molecular dynamics (MD) simulations. Given the widespread use of MD simulations in material and biomolecular sciences to get a better insight for experimental techniques such as thermal neutron scattering (TNS), the development of MDANSE has focused on providing a user-friendly, interactive, graphical user interface for analyzing many trajectories in the same session and running several analyses simultaneously independently of the interface. This first version of MDANSE already proposes a broad range of analyses, and the application has been designed to facilitate the introduction of new analyses in the framework. All this makes MDANSE a valuable tool for extracting useful information from trajectories resulting from a wide range of MD codes.

Neutron scattering techniques have been employed to investigate 1,2-dimyristoyl-sn -glycero-3-phosphocholine (DMPC) membranes in the form of multilamellar vesicles (MLVs) and deposited, stacked multilamellar-bilayers (MLBs), covering transitions from the gel to the liquid phase. Neutron diffraction was used to characterise the samples in terms of transition temperatures, whereas elastic incoherent neutron scattering (EINS) demonstrates that the dynamics on the sub-macromolecular length-scale and pico- to nano-second time-scale are correlated with the structural transitions through a discontinuity in the observed elastic intensities and the derived mean square displacements. Molecular dynamics simulations have been performed in parallel focussing on the length-, time- and temperature-scales of the neutron experiments. They correctly reproduce the structural features of the main gel-liquid phase transition. Particular emphasis is placed on the dynamical amplitudes derived from experiment and simulations. Two methods are used to analyse the experimental data and mean square displacements. They agree within a factor of 2 irrespective of the probed time-scale, i.e. the instrument utilized. Mean square displacements computed from simulations show a comparable level of agreement with the experimental values, albeit, the best match with the two methods varies for the two instruments. Consequently, experiments and simulations together give a consistent picture of the structural and dynamical aspects of the main lipid transition and provide a basis for future, theoretical modelling of dynamics and phase behaviour in membranes. The need for more detailed analytical models is pointed out by the remaining variation of the dynamical amplitudes derived in two different ways from experiments on the one hand and simulations on the other.

Protein low-frequency vibrational modes are an important portion of a proteins' dynamical repertoire. Yet, it is notoriously difficult to isolate specific vibrational features in the spectra of proteins. Given an appropriately chosen model peptide, and using different experimental conditions, we can simplify the system and gain useful insights into the protein vibrational properties. Combining neutron scattering, depolarized light scattering, and molecular dynamics simulations, we analyse the low frequency vibrations of biological molecules, comparing the results from a small globular protein, lysozyme, and an amphiphilic peptide, NALMA, both in solution and in powder states. Lysozyme and NALMA present similar spectral features in the frequency range between 1 and 10 THz. With the aid of MD simulations, we assign the spectral features to methyl groups' librations (1-5 THz) and hindered torsions (5-10 THz) in NALMA. Our data also show that, while proteins display boson peak vibrations in both powder and solution forms, NALMA exhibits boson peak vibrations in powder form only. This provides insight into the nature of this feature, suggesting a connection of BP collective motions to a characteristic length scale of heterogeneities present in the system. These results provide context for the use of model peptide systems to study protein dynamics; demonstrating both their utility, and the great care that has to be used in extrapolating results observed in powder to solutions.