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Shell ferromagnetism is a new functional property of certain off-stoichiometric Ni–Mn–In Heusler alloys, with a potential application in non-volatile magnetic memories and recording media. One key challenge in this field remains the determination of the structural and magnetic properties of the nanoprecipitates that are the result of an annealing-induced segregation process. Thanks to its unique mesoscopic length scale sensitivity, magnetic small-angle neutron scattering appears to be a powerful technique to disclose the microstructure of such annealing-induced nanoprecipitates. In this study, the microstructure of a zero-field-annealed off-stoichiometric Ni50Mn45In5 Heusler alloy is investigated by unpolarized magnetic small-angle neutron scattering. The neutron data analysis reveals a significant spin-misalignment scattering, which is mainly related to the formation of annealing-induced ferromagnetic nanoprecipitates in an antiferromagnetic matrix. These particles represent a source of perturbation which, due to dipolar stray fields, gives rise to canted spin moments in the surroundings of the particle–matrix interface. The presence of anticorrelations in the computed magnetic correlation function reflects the spatial perturbation of the magnetization vector around the nanoprecipitates. The magnetic field dependence of the zero crossing and the minima of the magnetic correlation function are qualitatively explained using the law of approach to ferromagnetic saturation for inhomogeneous spin states. More specifically, at remanence, the nanoprecipitates act magnetically as one superdefect with a correlation length that lies outside the experimental q range, whereas near saturation the magnetization distribution follows each individual nanoprecipitate. Analysis of the neutron data yields an estimated size of 30 nm for the spin-canted region and a value of about 75 nm for the magnetic core of the individual nanoprecipitates. more...

open access article OBJECTIVES The triblock copolymer Pluronic® is widely used in the personal care industry, including sun protection, for its film forming and solubilisation capabilities. In this study, the effect of three commonly used organic UV filters (ethylhexyl methoxycinnamate (EMC), ethylhexyl triazone (EHT) and avobenzone (AVB)) on the structure of Pluronic P123 micelles was investigated. METHODS The Pluronic P123 micelle structure has been investigated using dynamic surface tension, nuclear magnetic resonance (NMR) and small-angle neutron scattering (SANS). RESULTS Dynamic surface tension results show strong interactions between the UV filters and Pluronic® evident by sharp changes in the surface activity of the latter. The NMR results have revealed the creation of a hydrophobic microenvironment special to the Pluronic PPO core group in the presence of UV filters. Some interaction with the hydrophilic EO was also recorded, albeit weaker. This is further confirmed by SANS, where the Pluronic P123 micelles interacted with varying strengths with the UV filters, resulting in sharp changes in their size and shape. CONCLUSIONS We have demonstrated the sensitivity of the Pluronic P123 micelles to the presence of various UVA/B filters. The micelles shape varied from spherical to cylindrical as the concentration and type of the UV filters were varied. These variations in the shape are expected to have a significant effect on the sun protection factor (SPF), as it affects the solubilisation of the UV filters within a formulation in addition to the formulations’ rheological profile and film forming behaviour. more...

Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent tunability of their magnetic properties. To optimize particles for a specific application, it is crucial to interrelate their performance with their structural and magnetic properties. This review presents the advantages of small-angle X-ray and neutron scattering techniques for achieving a detailed multiscale characterization of magnetic nanoparticles and their ensembles in a mesoscopic size range from 1 to a few hundred nanometers with nanometer resolution. Both X-rays and neutrons allow the ensemble-averaged determination of structural properties, such as particle morphology or particle arrangement in multilayers and 3D assemblies. Additionally, the magnetic scattering contributions enable retrieving the internal magnetization profile of the nanoparticles as well as the inter-particle moment correlations caused by interactions within dense assemblies. Most measurements are used to determine the time-averaged ensemble properties, in addition advanced small-angle scattering techniques exist that allow accessing particle and spin dynamics on various timescales. In this review, we focus on conventional small-angle X-ray and neutron scattering (SAXS and SANS), X-ray and neutron reflectometry, gracing-incidence SAXS and SANS, X-ray resonant magnetic scattering, and neutron spin-echo spectroscopy techniques. For each technique, we provide a general overview, present the latest scientific results, and discuss its strengths as well as sample requirements. Finally, we give our perspectives on how future small-angle scattering experiments, especially in combination with micromagnetic simulations, could help to optimize the performance of magnetic nanoparticles for specific applications., Comment: 34 pages, 16 figures more...

Ti-containing micro-alloyed steels are often alloyed with molybdenum (Mo) to reduce nano-precipitate coarsening, although the mechanism is still disputed. Using small angle neutron scattering we characterised the precipitate composition and coarsening of Ti-alloyed and Ti-Mo-alloyed steels. The results demonstrate ~25 at.% of Ti is substituted by Mo in the (Ti, Mo)C precipitates, increasing both the precipitate volume percent and average size. Mo alloying did not retard precipitation coarsening, but improved lattice misfit between precipitate and matrix, contributing to better ageing resistance of the Ti-Mo-alloyed steel. This new understanding opens opportunities for designing ageing-resistant micro-alloyed steels with lean alloying elements. more...

Membrane proteins are present in a wide array of cellular processes from primary and secondary metabolite synthesis to electron transport and single carbon metabolism. A key barrier to applying membrane proteins industrially is their difficult functional production. Beyond expression, folding, and membrane insertion, membrane protein activity is influenced by the physicochemical properties of the associated membrane, making it difficult to achieve optimal membrane protein performance outside the endogenous host. In this review, we highlight recent work on production of membrane proteins in membrane augmented cell-free systems (CFSs) and applications thereof. CFSs lack membranes and can thus be augmented with user-specified, tunable, mimetic membranes to generate customized environments for production of functional membrane proteins of interest. Membrane augmented CFSs would enable the synthesis of more complex plant secondary metabolites, the growth and division of synthetic cells for drug delivery and cell therapeutic applications, as well as enable green energy applications including methane capture and artificial photosynthesis. more...

open access article Sunscreen lotions and creams are arguably the most popular products used to protect the skin against harmful UV radiation. Several studies have been conducted to untangle the internal microstructure of creams and lotions. However, the effect of UV filters and other materials such as preservatives, on the internal microstructure and the aesthetics of these products is not yet fully understood. Using small-angle neutron scattering (SANS), we were able to investigate the effect of adding the commonly used organic UV filters (avobenzone (AVB), ethylhexyl methoxycinnamate (EMC), ethylhexyl triazone (EHT) and bemotrizinol (BMT)) and the water soluble preservatives (1,5-pentanediol (1,5-PD) and 1,2-hexanediol (1,2-HD)), on the internal architecture and microstructure of an oil-in-water (o/w) based sunscreen lotion. Our findings highlight the complexities of these formulations, and how the introduction of different additives could influence their structure and possibly their performance. more...

The evolution of magnetic polarons in Sr doped LaCoO3 (La1-xSrxCoO3) single crystal and polycrystalline samples are investigated by employing dc and ac magnetic measurement and small angle neutron ... more...

We have designed, built, and validated a (quasi)-simultaneous measurement platform called NUrF, which consists of neutron small-angle scattering, UV-visible, fluorescence, and densitometry techniques. In this contribution, we illustrate the concept and benefits of the NUrF setup combined with high-performance liquid chromatography pumps to automate the preparation and measurement of a mixture series of Brij35 nonionic surfactants with perfluorononanoic acid in the presence of a reporter fluorophore (pyrene). more...

Summary CRISPR-Cas transcriptional circuits hold great promise as platforms for engineering metabolic networks and information processing circuits. Historically, prokaryotic CRISPR control systems have been limited to CRISPRi. Creating approaches to integrate CRISPRa for transcriptional activation with existing CRISPRi-based systems would greatly expand CRISPR circuit design space. Here, we develop design principles for engineering prokaryotic CRISPRa/i genetic circuits with network topologies specified by guide RNAs. We demonstrate that multi-layer CRISPRa/i cascades and feedforward loops can operate through the regulated expression of guide RNAs in cell-free expression systems and E. coli. We show that CRISPRa/i circuits can program complex functions by designing type 1 incoherent feedforward loops acting as fold-change detectors and tunable pulse-generators. By investigating how component characteristics relate to network properties such as depth, width, and speed, this work establishes a framework for building scalable CRISPRa/i circuits as regulatory programs in cell-free expression systems and bacterial hosts. A record of this paper’s transparent peer review process is included in the supplemental information . more...

To determine the longitudinal changes in retinal microstructure, microvasculature, microcirculation, and axonal and neuronal functions in patients with relapsing-remitting multiple sclerosis (RRMS) over the time course of about two years.A total of 30 patients (60 eyes) with RRMS were followed for a period of 27 ± 6 months and evaluated with a battery of clinical tests including low contrast letter acuity (LCLA), intraretinal layer thicknesses by optical coherence tomography (OCT), ganglion cell function by steady-state pattern electroretinography (PERG), axonal function by polarization-sensitive OCT, volumetric vessel density (VVD) by OCT angiography, and retinal tissue perfusion (RTP) by retinal function imager.Axonal function measured as retinal nerve fiber layer birefringence in the temporal quadrant and vessel density in the deep vascular plexus were significantly decreased at 2-year follow-up (P0.05). Subgroup analyses showed that the increased retinal blood flow volume occurred in patients with no evidence of disease activity (NEDA), and with stable or improved visual function (P0.05). There was no significant difference in the expanded disability state scale, LCLA, RTP, VVD, or PERG measures between the two visits (P0.05).To our best knowledge, this is the first 2-year prospective comprehensive study with a detailed assessment of retinal microstructure and neuronal functions in patients with RRMS. The recovery of retinal microcirculation occurred in patients with NEDA, and stable or improved visual function, suggesting these measurements as potential imaging biomarkers for monitoring disease progression. more...

\textit{Magnetospirillum gryphiswaldense} biosynthesize high quality magnetite nanoparticles, called magnetosomes, and arrange them into a chain that behaves like a magnetic compass. Here we perform magnetometry and polarized small-angle neutron scattering (SANS) experiments on a powder of freeze-dried and immobilized \textit{M. gryphiswaldense}. We confirm that the individual nanoparticles are single-domain particles and that an alignment of the particle moments in field direction occurs exclusively by a N\'eel-like rotation. Our magnetometry results of the bacteria powder indicate an absence of dipolar interactions between the particle chains and a dominant uniaxial magnetic anisotropy. Finally, we can verify by SANS that the chain structure within the immobilized, freeze-dried bacteria is preserved also after application of large magnetic fields of up to 1\,T., Comment: 7 pages, 5 figures more...

The ester sulfonate anionic surfactants are a potentially valuable class of sustainable surfactants. The micellar growth, associated rheological changes, and the onset of precipitation are important consequences of the addition of electrolyte and especially multi-valent electrolytes in anionic surfactants. Small angle neutron scattering, SANS, has been used to investigate the self-assembly and the impact of different valence electrolytes on the self-assembly of a range of ester sulfonate surfactants with subtly different molecular structures. The results show that in the absence of electrolyte small globular micelles form, and in the presence of NaCl, and AlCl3 relatively modest micellar growth occurs before the onset of precipitation. The micellar growth is more pronounced for the longer unbranched and branched alkyl chain lengths. Whereas changing the headgroup geometry from methyl ester to ethyl ester has in general a less profound impact. The study highlights the importance of relative counterion binding strengths and shows how the surfactant structure affects the counterion binding and hence the micelle structure. The results have important consequences for the response of such surfactants to different operational environments. more...

Designing and constructing model systems that embody the statistical mechanics of frustration is now possible using nanotechnology. We have arranged nanomagnets on a two-dimensional square lattice to form an artificial spin ice, and studied its fractional excitations, emergent magnetic monopoles, and how they respond to a driving field using X-ray magnetic microscopy. We observe a regime in which the monopole drift velocity is linear in field above a critical field for the onset of motion. The temperature dependence of the critical field can be described by introducing an interaction term into the Bean-Livingston model of field-assisted barrier hopping. By analogy with electrical charge drift motion, we define and measure a monopole mobility that is larger both for higher temperatures and stronger interactions between nanomagnets. The mobility in this linear regime is described by a creep model of zero-dimensional charges moving within a network of quasi-one-dimensional objects., Comment: 10 pages, 5 figures more...

Objective The purpose of this study was to quantify retinal structural, vascular, and functional changes in patients with relapsing-remitting multiple sclerosis (RRMS) over 1 year. Methods Eighty-eight eyes of 44 patients with RRMS underwent assessments of low contrast letter acuity (LCLA), retinal ganglion cell function detected by the steady-state pattern electroretinogram (PERG), axonal microstructural integrity measured as birefringence, intraretinal layer thicknesses by ultra-high-resolution optical coherence tomography (OCT), volumetric vessel density (VVD) by OCT angiography, and retinal tissue perfusion (RTP) by the Retinal Function Imager (RFI). All measurements were performed at baseline and 1-year follow-up. The impacts of disease activities and a history of optic neuritis (ON) were analyzed. Results Compared to baseline, there were no significant differences in all variables (P > 0.05), except for the axonal birefringence and RTP. The birefringence's of the retinal fiber layer at the temporal and superior quadrants was significantly decreased (P < 0.05), whereas RTP was significantly increased (P < 0.05). In the subgroup with ON, significantly longer PERG latency and decreased VVD were observed at follow-up (P < 0.05). In patients with improved LCLA, significantly increased RTP and decreased VVD (P < 0.05) were also observed. Conclusions This is the first longitudinal study that assessed the RTP and VVD, along with other retinal structural and functional parameters in MS. The recovery of retinal vascular function occurred with the improved LCLA, suggesting that these measurements may be associated with disease progression. Translational Relevance The retinal microvascular changes could be potential biomarkers for monitoring therapeutic efficacy in MS. more...

In metastable β-Ti alloys, nanoscale isothermal ω-phase (ωiso) precipitates are regarded as the nucleation sites for the α strengthening phase. Here we investigate the precipitation kinetics of the ωiso precipitates as a function of cooling rate (air cooling and water quenching) after β-solutionising. A combined in situ small-angle neutron scattering (SANS) and electrical resistivity measurement approach was used during ageing of Ti–5Al–5Mo–5V–3Cr wt% (Ti-5553) alloy at 300 °C and 325 °C up to 8 h. The SANS modelling was consistent with ellipsoid shaped particles for the ωiso precipitates, for both air-cooled and water-quenched samples. The precipitates attained a maximum size (equatorial diameter) of ∼21 nm and ∼17 nm after 2 h and 4 h of ageing the water-quenched and air-cooled samples respectively. Although the air-cooled samples showed delayed nucleation in comparison to water-quenched sample, the volume fraction became approximately the same (∼11%) after ageing for 8 h. The average value of the activation energy for ωiso nucleation from the β-phase matrix was determined as 122 kJ mol−1 from electrical resistivity data using a modified Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. The hardness increased with ageing time, with water quenching leading to a higher final value of hardness than air cooling. more...

Purpose The purpose of this study was to investigate local differences of macular retinal ganglion cell (RGC) function by means of the steady-state pattern electroretinogram (SS-PERG). Methods SS-PERGs were recorded in healthy subjects (n = 43) in response to gratings (1.6 c/deg, 15.63 reversals/s, and 98% contrast) presented on an LED display (800 cd/m2, 12.5 degrees eccentricity at 30 cm viewing distance) partitioned in triangular sectors (inferior [I]; nasal [N]; superior [S]; and temporal [T]) or concentric regions (central [C] and annulus [A]). For each partition, response amplitude (nV), amplitude adaptation (% change over recording time), phase/latency (deg/ms), and oscillatory potentials (OPs) amplitude (root mean square [RMS] nV) were measured. Data were analyzed with Generalized Estimating Equation (GEE) statistics. Results Amplitude differed (P < 0.001) between sectors (I: 254 nV; N: 328 nV; S: 275 nV; T: 264 nV; and N>T, I) as well as concentrically (C: 684 nV; A: 323 nV; and C>A). Latency did not differ between sectors (range = 53–54 ms, P = 0.45) or concentrically (range = 51–51 ms, P = 0.7). Adaptation did not differ (P = 0.66) concentrically (C: −19% and A: −22%) but differed (P = 0.004) between sectors (I: +25% and S: −29%). The OP amplitude did not differ (P = 0.5) between sectors (range = 63–73 nV) as well as concentrically (range = 82–90 nV, P = 0.3). Conclusions Amplitude profiles paralleled RGC densities from histological studies. Adaptation profile suggested greater autoregulatory challenge in the inferior retina. Latency profile may reflect axonal conduction time to the optic nerve head assuming a direct relationship between axon length and its size/velocity. Location-independent OPs may reflect preganglionic activity. Translational Relevance Normal macular RGC function displays local differences that may be related to local vulnerability in optic nerve disorders. more...

A biskyrmion consists of two bound, topologically stable, skyrmion spin textures. These coffee-bean-shaped objects are observed in real space in thin plates using Lorentz transmission electron microscopy (LTEM). From LTEM imaging alone, it is not clear whether biskyrmions are surface-confined objects, or, analogous to skyrmions in noncentrosymmetric helimagnets, 3D tube-like structures in a bulk sample. Here, the biskyrmion form factor is investigated in single- and polycrystalline-MnNiGa samples using small-angle neutron scattering. It is found that biskyrmions are not long-range ordered, not even in single crystals. Surprisingly all of the disordered biskyrmions have their in-plane symmetry axis aligned along certain directions, governed by the magnetocrystalline anisotropy. This anisotropic nature of biskyrmions may be further exploited to encode information. more...

We apply the truncated singular value decomposition (SVD) to extract the underlying 2D correlation functions from small-angle scattering patterns. We test the approach by transforming the simulated data of ellipsoidal particles and show that also in case of anisotropic patterns (i.e. aligned ellipsoids) the derived correlation functions correspond to the theoretically predicted profiles. Furthermore, we use the truncated SVD to analyze the small-angle x-ray scattering patterns of colloidal dispersions of hematite spindles and magnetotactic bacteria in presence of magnetic fields, to verify that this approach can be applied to extract model-free the scattering profiles of anisotropic scatterers from noisy data., Comment: 14 pages, 4 figures more...

An alloy of Fe 35 Al 50 B 15 has been prepared by milling under vacuum for 840 h. The X-ray diffraction pattern shows only two broad peaks stemming from a highly disordered structural state. The magnetic state was characterized by AC susceptibility. It displays sharp maxima around 20 K (21 K) in the real (complex) components. The maxima are due to the onset of a spin frozen disordered arrangement, and shift to higher temperature with increasing frequency. The magnetic dynamics is accounted for a power-law in the vicinity of the transition. Values of zv = 9.0(3) and T 0 = 19.5(1) K are obtained. Complex susceptibility dynamic scaling results in a large β = 1.3(1). The values extracted for the critical exponents are close to those of glassy magnets and are an indication of a nonconventional transition. The nonlinear susceptibility reveals a peak at the transition, which is affected by the oscillating h more...

Artificial spin ices are often spoken of as being realisations of some of the celebrated vertex models of statistical mechanics, where the exact microstate of the system can be imaged using advanced magnetic microscopy methods. The fact that a stable image can be formed means that the system is in fact athermal and not undergoing the usual finite-temperature fluctuations of a statistical mechanical system. In this paper we report on the preparation of artificial spin ices with islands that are thermally fluctuating due to their very small size. The relaxation rate of these islands was determined using variable frequency focused magneto-optic Kerr measurements. We performed magnetic imaging of artificial spin ice under varied temperature and magnetic field using X-ray transmission microscopy which uses X-ray magnetic circular dichroism to generate magnetic contrast. We have developed an on-membrane heater in order to apply temperatures in excess of 700 K and have shown increased dynamics due to higher temperature. Due to the ‘photon-in, photon-out' method employed here, it is the first report where it is possible to image the microstates of an ASI system under the simultaneous application of temperature and magnetic field, enabling the determination of relaxation rates, coercivties, and the analysis of vertex population during reversal. more...

Microelectrode arrays (MEAs) have proved to be useful tools for characterizing electrically active cells such as cardiomyocytes and neurons. While there exist a number of integrated electronic chips for recording from small populations or even single cells, they rely primarily on the interface between the cells and 2D flat electrodes. Here, an approach that utilizes residual stress‐based self‐folding to create individually addressable multielectrode interfaces that wrap around the cell in 3D and function as an electrical shell‐like recording device is described. These devices are optically transparent, allowing for simultaneous fluorescence imaging. Cell viability is maintained during and after electrode wrapping around the cel and chemicals can diffuse into and out of the self‐folding devices. It is further shown that 3D spatiotemporal recordings are possible and that the action potentials recorded from cultured neonatal rat ventricular cardiomyocytes display significantly higher signal‐to‐noise ratios in comparison with signals recorded with planar extracellular electrodes. It is anticipated that this device can provide the foundation for the development of new‐generation MEAs where dynamic electrode–cell interfacing and recording substitutes the traditional method using static electrodes. more...