cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1810044
title: Understanding the structure of sodium laureth sulfate and cocamidopropyl betaine in water

description: The objective of this research is to understand the detailed structure of water-surfactant solutions as a function of concentration.  This is important as these materials form the main components of personal care products and this fundamental understanding will provide the basis of new formulations.
DOI: 10.5286/isis.e.rb1810074
title: Negative thermal expansion in V2OPO4

description: Much effort has been devoted to the research of new NTE materials and the understanding of the mechanism driving this phenomenon. As part of our ERC grant on orbital molecules, we have recently discovered that the vanadium oxyphosphate V2OPO4 displays NTE at high temperatures associated with a charge ordering transition. To determine the origin of the NTE, we propose to measure precise atomic coordinates and anisotropic thermal displacement parameters as a function of temperature from RT to 1200 K, well above TCO = 605 K, through neutron powder diffraction. Neutrons are needed to obtain accurate information for the oxygen atoms. 2 days are required to collect a series of patterns in the RT-1200 K range, during heating and cooling, using a 3g powder sample.
DOI: 10.5286/isis.e.rb1810277
title: Polyoxometallate surfactant adsorption at solution surfaces

description: Polyoxometallates (POM) are well defined transition metal clusters with a range of interesting catalytic, magnetic and optical properties. To make efficient use of these materials they are often supported on other materials to provide a high surface area open network, allowing access to the POMs. The use of solution self-assembly to structure POMs directly or evenly dispersed within a silica matrix is therefore attractive, so we are studying the synthesis and organisation of POM-headed surfactants, with C12, C14 or C16 hydrocarbon tails to incorporate them into POM-surfactant-silica films as supports. Here we propose to study the surface adsorption of POM-amphiphiles alone and in mixtures with a nonionic surfactant using contrast variation to determine the structures. Surface adsorption characterises both the mixing of these species and the interface for future silica nucleation & growth
DOI: 10.5286/isis.e.rb1810590
title: Phase separation and embrittlement in duplex stainless steel

description: Duplex stainless steels (DSS), containing both austenite and ferrite phases, are attractive materials owing to a combination of high strength and excellent corrosion resistance and are a natural material choice in applications such as e.g. pressurized equipment in the nuclear, chemical and pulp & paper industries. To increase efficiency in these applications, higher service temperatures and operational temperatures are required. However, the service temperature of DSS grades is limited to ~250°C. Above this temperature, within the ferrite phase, the alloying elements separate into Fe and Cr rich regions, due to phase separation (PS) phenomena, and the material is embrittled. In fully ferritic alloys, PS has been studied for a long time but less work has been performed on studying PS in commercial grade duplex alloys. We propose to study embrittlement in commercially available DSS.
DOI: 10.5286/isis.e.rb1820049
title: Non-ionic surfactant induced desorption of a strongly bound cationic layer from mica

description: In this proposal we request beamtime to study the unexpected behaviour of a strongly bound bilayer of the cationic surfactant didodecyldimethylammonium bromide on the anionic mica surface in the presence of the non-ionic surfactant hexaethylene glycol monododecyl ether. This builds on previous work at ISIS where a cationic surfactant layer was found to be persistent to an extended wash with water and salt solutions, but upon exposure to sodium dodecyl sulfate at concentrations below the critical micelle concentration the layer thickened, and when the anionic surfactant concentration reached the critical micelle concentration the cationic layer desorped completely from the mica surface.
DOI: 10.5286/isis.e.rb1820079
title: High Energy Spin Excitations in Electron Overdoped NaFe0.7Ni0.3As

description: The interplay between magnetism and superconductivity in iron-based high-temperature superconductors are of great interest in condensed matter physics research. These two properties can dramatically evolve with electron or hole doping in iron-based materials. To understand the interplay between magnetism and superconductivity and their co-evolution with doping across the phase diagram, magnetic excitation spectra obtained via neutron scattering are critical. Here we propose an inelastic neutron scattering experiment on high energy (mainly, also with low energy measurement) spin wave excitation in highly electron-doped NaFe0.7Ni0.3As to contribute to the magnetic excitation spectra of the NaFeAs family of superconductors, thus completing the phase diagram of it. We submitted the same proposal in 2016 and were granted 7 days beamtime, but the experiment canceled due to MAPS upgrade.
DOI: 10.5286/isis.e.rb1520015
title: Hard-Axis Ordering in Ferromagnetic CeAgSb2

description: We propose to study the low-energy spin fluctuations in ferromagnetic metal CeAgSb2. The ordered moment is oriented away from the direction favored by the lattice. Recent theory, which invokes "Indian rope trick" scenario suggests that the hard axis ordering is stabilized by the strong spin fluctuations when ferromagnetism is suppressed to low temperatures. Here we propose to measure the transverse fluctuations of the ordered moment in zero field and also at high magnetic field, which suppresses the fluctuations and drives the ordering along the true magnetic easy-axis. Our measurements will test the "Indian rope trick" scenario directly.
DOI: 10.5286/isis.e.rb1600017
title: The Interaction of Grp1 with Membranes Containing Signalling Phospholipids
DOI: 10.5286/isis.e.rb1600049
title: The structure of prilocaine in solution - crossing the BBB
DOI: 10.5286/isis.e.rb1600050
title: Scattering Length Determination for 193Ir
DOI: 10.5286/isis.e.rb1610234
title: SANS Investigation of Mixtures of Ionic Liquids

description: Small-angle neutron scattering  will investigate in phase diagrams from binary mixtures of different chain lengths of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides ([R-MIM][Tf2N]). Previous work with mixtures of the 1-ethyl and 1-dodecyl derivatives (Sans2d) showed organisation of the long-chain material in the shorter one. This study extends the work to examine self-organisation in different combinations of chain lengths. First experiments will look at the organisation of [C12MIM][Tf2N] in [Cn-MIM][Tf2N] (n = 4, 6, 8, 10) and of [Cn-MIM][Tf2N] in [EMIM][Tf2N] (n = 4, 6, 8, 10): results will allow inform the design of a second series of experiments that will look at different binary combinations. One of the ionic liquids will be used in perdeuterated form to generate usable contrast.
DOI: 10.5286/isis.e.rb1610262
title: The structure and orientation of the Bam complex in the Gram-negative outer membrane

description: The proteins of the outer membrane of Gram-negative bacteria are critical for bacterialsurvival, from providing basic physiological functions, to aiding virulence and multidrugresistance. The Bam complex has been found to be essential for folding these proteins intothe outer membrane. The process by which this is achieved is unknown. Key to thisunderstanding is the knowledge of the structure of the complex and its individualcomponents. We aim to continue our investigation of the Bam complex by studying the complete BamABCDE complex and in particular identify how the individual components are organised on the membrane surface. To do this will use neutron reflectometry and specific deuteration to probe the structure of the Bam complex in a model E.coli outer membrane and elucidate the scaffolding of this essential complex on the membrane surface for the first time.
DOI: 10.5286/isis.e.rb1610353
title: Investigation of the solution structure and pore dynamics of Bacillus anthracis protective antigen stabilised in lipid nanodiscs.

description: Understanding the nature of protein translocating events through bacterial pores offers an uniqueopportunity to develop novel drug delivery systems, whilst also providing invaluable informationrelating to their biology. As part of this proposal we wish to evaluate protein translocation eventsthrough lipid nanodiscs containing protective antigen (PA), a pore forming protein produced by the bacterium Bacillus anthracis. The ability of this pore to translocate large proteins is well documented, current theory states these must unfold to allow for passage through lumen, an energy intensive process. Our hypothesis is that proteins require the PA pore to expand allowing for transit. The key objective is to determine the PA pore shape, solution structure and structural alterations that occur as a function of pH using SANS, complementing our neutron reflectometry experiment at ILL (8-03-848).
DOI: 10.5286/isis.e.rb1610453
title: Effect of serum and electrolyte on the structure of nanoemulsions intended for the treatment of cancer

description: Nanoemulsions (NE) i.e. nanoparticles containing a fluid lipid or oil dispersed in water and stabilized by a surfactant particles have attracted considerable attention as vehicles for the delivery of poorly-water soluble drugs. We have recently developed a series of novel nanoemulsions containing either trilaurin or soybean oil as the disperse phase and stabilised by the non-ionic surfactant, oleyl polyoxethylene (10) ether. In order to use the NE as vehicles for the delivery of cancer it is essential to understand the effect of electrolyte and plasma proteins on the structure of the NE. The proposed SANS study will therefore determine the effect of electrolyte and plasma proteins on the properties of the NE. The insight provided by the study should provide a better understanding of the potential of NE as vehicles for drug delivery.
DOI: 10.5286/isis.e.rb1620309
title: Oxidation of bilayer of labelled DPPC by aqueous hydroxyl radical  elucidating a mechanism for atmospheric science

description: Oxidation of atmospheric aerosol can produce cloud condensation nuclei capable of changing the reflectivity and lifetime of clouds. The oxidation of organic film on atmospheric mineral dust may activate mineral dust  into cloud droplets. To assess the atmospheric importance the chemical lifetime of the organic material to a common atmospheric oxidant (OH radical) must be measured and compared to deposition lifetime of the mineral aerosol (4-10 days). The chemical lifetime will be assessed by measuring the rate of oxidation of a bilayer of a lipid DPPC from the solid-liquid interface of a silica mineral window, using neutron reflection. Selective deuteration, the ability to measure film thickness and amount of material at the solid-liquid interface will allow chemical mechanism to be deduced. Preliminary studies show the experiment viable, and these data are needed for publication.
DOI: 10.5286/isis.e.rb1710207
title: Structural insight into the mechanistic process of permeabilization into model membranes by an antimicrobial peptide

description: The aim of this study is to try to understand how antimicrobial peptides bind to model lipid monolayers mimicking different cell membrane types. Following our previous work, this study will move into model lipid monolayers containing 2-3 key membrane components. Their combined use helps us to better understand the effects of membrane composition on the amount and location of peptide binding. This constitutes a crucial part of the peptide action mechanisms when disrupting different membranes. The molecular basis of selectivity will in turn help improve the potency of these peptides whilst keeping the toxicity at the minimum.
DOI: 10.5286/isis.e.rb1710225
title: The phase diagram of the spin-density-wave metamagnet Sr3Ru2O7

description: Sr3Ru2O7 is an unusual layered oxide metamagnetic metal. It has been known for some time that the application of a large magnetic field (~8 T) perpendicular to the RuO2 planes induces a new "A" phase at low temperatures (T&lt;1.5K). The A  phase has thermodynamic and electronic transport anomalies which define its boundaries.  It also has anisotropic electronic properties. We have recently used WISH to identify the A phase as spin density wave (SDW) order and discover a neighbouring "B" phase at slightly higher field. Here we propose to: (i) map out the temperature/field phase boundaries of the A & B phases in detail and measure the T-dependence of the order parameters as a function of field (both are difficult by other techniques); (ii) determine whether electronic anomalies for magnetic fields applied within the RuO2 planes also correspond to SDW order.
DOI: 10.5286/isis.e.rb1710249
title: Atomistic modeling of temperature-driven structural phase transition in ferroelectric solid solution

description: Ferroelectric materials, mainly Pb-containing, have widespread applications in our modern-day life, primarily used as sensors, actuator and memories. However challenges still remain to understand the structure-property relations at the atomic level, which is crucial in order to develop bespoke materials with improved qualities, and to find Pb-free alternatives to avoid environmental concerns. Here we aim to investigate a couple of novel reduced Pb-content ferroelectric systems, which have been recently shown to be promising high-temperature piezoelectric materials with the so-called morphotropic phase boundary (MPB). Pair distribution functions as a function of composition at ambient and non-ambient temperature will be studied with a view to establish how the chemical variation can influence the local structure and atomic dynamics, and consequently impacts the properties of the system.
DOI: 10.5286/isis.e.rb1710479
title: Diffusion in a zeolite under flow conditions

description: Quasielastic neutron scattering is often used to measure the diffusion of organic materials inside the pores of catalysts. Although generally performed in a sealed system, a flowing reactor is of greater interest as it more closely reflects realistic use of the materials. If it is possible to make these measurements it will demonstrate that it should be possible to measure reacting samples in-situ. There is also the possibility that such a system may provide insight into flow patterns within a reactor. This experiment aims to be the first quasielastic neutron scattering study performed under a gas flow using newly created sample cans.
DOI: 10.5286/isis.e.rb1720138
title: Multi-phonon scattering and anharmonicity in zinc oxide

description: Understanding the thermal conductivity of zinc oxide is of central importance in assessing its potential for a wide variety of applications in optoelectronics, power electronics and thermoelectric devices. Our single-crystal INS studies on LET demonstrate that we are able to model the one-phonon scattering using DFT and to measure the energy broadening from phonon-phonon scattering. Our powder INS studies on MARI reveal a red-shift in the multi-phonon scattering that is the signature of anharmonicity. We now propose to study the multi-phonon scattering by single-crystal INS using the MERLIN spectrometer. Our results will be the most direct test possible of the anharmonic corrections to the DFT. We expect to obtain a deeper understanding of anharmonicity in general, and the temperature dependence of the thermal conductivity of this technologically important material in particular.
DOI: 10.5286/isis.e.rb1720500
title: Designing a model of the epithelial apical plasma membrane to facilitate study of structure-function relationships governing polyphenol bioa

description: This beam time application aims to provide preliminary data to support a wider research programme and grant application that will seek to develop a sophisticated and effective lipid bilayer model of the epithelial apical plasma membrane that is amenable to study by neutron reflectometry.  The development of this model will allow the expansion of NR to nutrient and drug absorption and to furthering our understanding of how and why molecules can cross these barriers. Our aim is to provide effective membrane models that will enable molecular interaction with the epithelial surface to be investigated, and thus provide an understanding of the role of each membrane constituent. This preliminary study looks to maintain a relatively simplified model where we focus on creating a robust bilayer structure where asymmetry is consistently maintained under different temperature and pH environments.
DOI: 10.5286/isis.e.rb1770014
title: Magnetic Ground State of Pyrochlore Ruthenates

description: We propose to clarify magnetic properties of Ca-doped Nd227 pyrocholore ruthenates, (Nd1-xCax)2Ru2O7., by changing the Ca concentration. The Ru spin forms a long-range ordered state for x=0 and the magnetic transition temperature is being suppressed with increasing the carrier concentration. A quantum critical point where the magnetic ordered state disappears is suggested to exist around x~0.20. We aim to determine the carrier doping dependence of a long-range ordered state of Ru spins clarifying a magnetic phase diagram of this system. We try to investigate the change in the Ru spin against the carrier concentrationin conjunction with density functional theory calculations in comparison with the results obtained in the Nd227 irridate.
DOI: 10.5286/isis.e.rb1800112
title: Decoupling effect between protein and water

description: Water plays a critical role in life. A hydration level, h ~ 0.2 g water/g protein, is found to be the minimum for the dynamical transition in protein at Td ~ 200 K. This temperature is universal for proteins and ascribed to the surface hydration water. However, our OSIRIS neutron data on perdeuterated cytochrome P450 (CYP) and its hydrogenated counterpart showed that the Td of hydration water shifts significantly to higher values when decreasing the instrument resolution, while the Td for the protein remains essentially unchanged. OSIRIS afforded us two resolutions (25.4 and 99 ueV) which we added to data from HFBS at NIST at 1ueV resolution. These results suggests that the dynamical transition might have a different physical origin from that of its surface water. To further confirm these findings, we want to try a structurally and functionally different protein, GFP, at OSIRIS.
DOI: 10.5286/isis.e.rb1810151
title: Local Structure in Neodymium Doped Ceria

description: Doped cerias are currently being used as oxide ion conducting electrolyte materials in solid oxide fuel cells (SOFCs). The conduction mechanism in electrolytes is dependent on the local structure. We have found very unusual local structure features in praseodymium doped ceria that cannot be accounted for in the average crystallographic model. The present proposal seeks to examine whether these local features are also present in the closely related neodymium doped ceria or are unique to the praseodymium doped system. A study of the local structure in neodymium doped ceria as a function of composition and temperature is proposed.
DOI: 10.5286/isis.e.rb1810577
title: Influence of shear on polymer adsorption at solid / liquid interfaces

description: Lubricants contain a complex mixtures of polymers and base oils that must provide protection to moving surfaces with minimal energy loss due to friction or viscous drag.  There is considerable interest in the relationship between bulk and interfacial properties of lubricants, especially under the extremes of pressure, temperature and shear rate are routinely found in engines.  Here we propose a simple model system, based on polybutadiene and squalane, for which we have already established the phase behaviour under quiescent conditions.  Interestingly, rheometry using a multi-pass rheometer indicates that phase separation may occur under moderate shear rates.  We will use NR to determine surface segregation under quiescent conditions and under shear using a new setup on INTER.  Results will give valueable insights into the modes of action and failure in model lubricants.
DOI: 10.5286/isis.e.rb1810618
title: In-Operando Neutron Imaging of Lithium Intercalation in Graphite and structure evolution in Lithium Sulphur Cells

description: Li-ion batteries have been one of the transformative technologies of the 20th century and have enabled a revolution in consumer electronics in the 21th century and enable technological progress with applications like automotive power trains and mobile phones. Further, Li-Sulphur chemistry is a promising candidate for the post Li-ion era and provide a 10 times higher theoretical capacity but shows significant loss of capacity after the first cycles.In our research project, we will study the charging and discharging process of a common Graphite and a new Sulphur electrode by neutron imaging. For the first time, we will image the Li transport inside a battery due to the high absorption coefficient for neutrons. In this study, we will get a better understanding of structure evolution and capacity fade effects in the electrode which helps to improve the next generation of Li-ion batteries.
DOI: 10.5286/isis.e.rb1510508
title: Investigation of the interactions of perfluoroalkyl substances with model worm and plant biomembranes

description: Perfluoroalkyl substances (PFASs) are fully fluorinated, stabile, and surface-active compounds. They contain both a hydrophobic fluorinated carbon chain and an ionizable hydrophilic functional group, and can interact with biological membranes through different pathways, such as adsorption, penetration and displacement. PFASs have been found to accumulate in organisms in the environment, but there is a lack of knowledge on the mechanisms behind the accumulation. This proposal aims to use neutron reflection to investigate the interactions of perfluorooctane sulfonate, perfluorononanoate and perfluorohexanoate with standard eukaryotic mimic biomembrane and compare with model plant membrane to elucidate the influence of different functional groups and chain lengths on the sorption/accumulation behavior at the two different types of membranes.
DOI: 10.5286/isis.e.rb1520040
title: Muon spin relaxation study on frustrated pyrohafnates R2Hf2O7 (R = Nd, Sm, Gd, Tb)

description: With the observations of spin ice behaviour in Dy2Ti2O7 and Ho2Ti2O7 the rare earth pyrochlores R2B2O7 have evolved as a hot topic of current research activities. In our effort to search for novel 227 rare earth pyrochlores we have synthesized and investigated the magnetic properties of the new hafnate pyrochlore family that has been investigated only to very limited extent. Our investigations on R2Hf2O7 (R = Nd, Sm, Gd, Tb) show interesting magnetic ground states ranging from long range magnetic order in Nd2Hf2O7 to possible glassy behavior in Tb2Hf2O7 due to the critical role of frustration and the crystal field effect. Because of the high sensitivity of muons to extremely small magnetic fields and suitability of muSR for investigating the frustrated magnetism, it would be of interest to investigate the magnetic properties of R2Hf2O7 (R = Nd, Sm, Gd, Tb) using the muon spin relaxation.