Elastic incoherent neutron and quasi-elastic scattering studies if aligned DMPC multilayers at different hydrations
Proc. Natl. Acad. Sci. U. S. A
Influenza infects an estimated 9-35 million individuals each year in the United States and is a c... more Influenza infects an estimated 9-35 million individuals each year in the United States and is a contributing cause for between 12,000 and 56,000 deaths annually. Seasonal outbreaks of influenza are common in temperate regions of the world, with highest incidence typically occurring in colder and drier months of the year. Real-time forecasts of influenza transmission can inform public health response to outbreaks. We present the results of a multiinstitution collaborative effort to standardize the collection and evaluation of forecasting models for influenza in the United States for the 2010/2011 through 2016/2017 influenza seasons. For these seven seasons, we assembled weekly real-time forecasts of seven targets of public health interest from 22 different models. We compared forecast accuracy of each model relative to a historical baseline seasonal average. Across all regions of the United States, over half of the models showed consistently better performance than the historical baseline when forecasting incidence of influenza-like illness 1 wk, 2 wk, and 3 wk ahead of available data and when forecasting the timing and magnitude of the seasonal peak. In some regions, delays in data reporting were strongly and negatively associated with forecast accuracy. More timely reporting and an improved overall accessibility to novel and traditional data sources are needed to improve forecasting accuracy and its integration with real-time public health decision making.2019-01-15T00:00:00Z30647115PMC6386665612
Here we report the extreme toxicity in vitro of Bi(OH) 3 and α-Bi 2 O 3 nanoparticles (NPs), obta... more Here we report the extreme toxicity in vitro of Bi(OH) 3 and α-Bi 2 O 3 nanoparticles (NPs), obtained through a facile synthesis with an average single particle size of 6-10 nm, tested on malignant gliosarcoma 9L and MCF-7 human breast cancer cells. For both nanomaterials, clonogenic assays reveal a mortality of over 90% in 9L and MCF-7 cells for a concentration of 50 μg/mL after incubation for 24 h. Moreover, the NPs show a significant mortality of up to 60% in the malignant cells at the very low concentration of 6.25 μg/mL. In contrast, at the same concentration, the nanomaterials exhibit no noticeable mortality towards normal Madin-Darby canine kidney cells. The internalisation of the NPs was demonstrated using flow cytometry and confocal microscopy was used to investigate when the loss of cell viability starts. The NPs show a faster cell death in 9L cells compared with MCF-7 cells, demonstrated via the identification of apoptosis through increased sub G 1 levels after 24 h of NP incubation. Cleavage is identified as the main apoptotic nuclear morphology in 9L, which suggests the presence of reactive oxygen species.
Synchrotron radiation is unique in its ability to deliver dose at high dose rates using kiloelect... more Synchrotron radiation is unique in its ability to deliver dose at high dose rates using kiloelectronvolt photons. We are investigating the use of Tantalum pentoxide (Ta2O5) nano-structured particles (NSPs) that are to date unexplored in synchrotron radiation fields as they have high atomic number (Z=73) are biocompatible and are therefore potential radio sensitizers. We exposed cell culture flasks containing 9L gliosarcoma tumour cells or Madin-Darby Canine Kidney (MDCK) non-tumour cells to the NSPs and treated the cells using a broad synchrotron beam (140 keV median energy; average dose rate of 50 Gy/s) at the Australian Synchrotron. We compare the results with those from similar cells treated using a conventional 150 kVp orthovoltage field (dose rate of 0.0127 Gy/s). The results reveal that the high dose-rate synchrotron irradiation is more effective at killing the 9L cells relative to the MDCK cells than the orthovoltage irradiation. On the other hand, the NSPs are more effective at radiosensitizing the 9L cells compared to the MDCK cells in the orthovoltage radiation field, which is due to the NSP energy dependence in the kilovoltage energy range. Both the dose rate and energy spectrum need to be considered in future studies with synchrotron activation radiotherapy (SART).
1. Introduction 3282. Basic concepts of neutron scattering 3292.1 Introduction 3292.2 Neutron-sca... more 1. Introduction 3282. Basic concepts of neutron scattering 3292.1 Introduction 3292.2 Neutron-scattering functions 3312.3 Coherent and incoherent neutron scattering. The particular role of hydrogen in incoherent scattering 3322.4 Total elastic scattering, EISF and mean square displacement (MSD) 3332.5 Quasielastic scattering and relaxation function 3342.6 Inelastic scattering and density of states 3353. Experimental aspects and instruments 3353.1 Energy and space resolution 3353.2 General sample aspects 3353.3 Potential effects of D2O on dynamics 3363.4 Experimental 2H (deuterium) labelling 3364. Physics of protein dynamics 3364.1 Models 3364.2 The dynamical transition 3384.3 Effective force constants 3395. Dynamics of hydrated protein powders 3395.1 First experiments on myoglobin 3405.2 Dynamical transitions in other proteins 3405.3 The role of hydration water 3415.4 Influence of the solvent 3445.5 Diffusional motions within proteins by QENS 3465.6 Inelastic neutron scattering and ...
Amphipols are a class of polymeric surfactants that can stabilize membrane proteins in aqueous so... more Amphipols are a class of polymeric surfactants that can stabilize membrane proteins in aqueous solutions as compared to detergents. A8-35, the best-characterized amphipol to date, is composed of a polyacrylate backbone with ~35% of the carboxylates free, ~25% grafted with octyl side-chains, and ~40% with isopropyl ones. In aqueous solutions, A8-35 self-organizes into globular particles with a molecular mass of ~40 kDa. The thermal dynamics of A8-35 particles was measured by neutron scattering in the 10-picosecond, 18-picosecond, and 1-nanosecond time-scales on natural abundance and deuterium-labeled molecules, which permitted to separate backbone and side-chain motions. A parallel analysis was performed on molecular dynamics trajectories (Perlmutter et al., Langmuir 27:10523-10537, 2011). Experimental results and simulations converge, from their respective time-scales, to show that A8-35 particles feature a more fluid hydrophobic core, predominantly containing the octyl chains, and ...
Journal of the Royal Society, Interface / the Royal Society, Jan 6, 2014
It is a long debated question whether catalytic activities of enzymes, which lie on the milliseco... more It is a long debated question whether catalytic activities of enzymes, which lie on the millisecond timescale, are possibly already reflected in variations in atomic thermal fluctuations on the pico- to nanosecond timescale. To shed light on this puzzle, the enzyme human acetylcholinesterase in its wild-type form and complexed with the inhibitor huperzine A were investigated by various neutron scattering techniques and molecular dynamics simulations. Previous results on elastic neutron scattering at various timescales and simulations suggest that dynamical processes are not affected on average by the presence of the ligand within the considered time ranges between 10 ps and 1 ns. In the work presented here, the focus was laid on quasi-elastic (QENS) and inelastic neutron scattering (INS). These techniques give access to different kinds of individual diffusive motions and to the density of states of collective motions at the sub-picoseconds timescale. Hence, they permit going beyond ...
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Papers by M. Tehei