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Typical scattering pattern collected with the scintillation detector of KWS-2 as raw data (a) and corrected data for detector sensitivity (b).
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The KWS-2 small-angle neutron diffractometer operated by JCNS at FRM II is upgraded and optimized towards high intensity and wide Q-range studies of mesoscopic structures and structural changes due to rapid kinetics and becomes a dedicated SANS instrument to soft-matter and biology. The high intensity permits fast measurement of small or weak scatt...
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Context 1
... readout electronics enables fast signal and data processing (about 0.6μs statistical dead-time) and allows for the acquisition of stable and reliable count rates up to 0.6MHz. Because of the photomultipliers array and the scintillator active area made of 4x4 plates glued together, a grid-like structure corresponding to detector regions with lower sensitivity characterizes the raw scattering patterns ( figure 2a). Therefore, corrections that take into account the detector sensitivity measured with an incoherent standard sample (Plexiglas) must be always applied to the raw data ( figure 2b). ...
Context 2
... of the photomultipliers array and the scintillator active area made of 4x4 plates glued together, a grid-like structure corresponding to detector regions with lower sensitivity characterizes the raw scattering patterns ( figure 2a). Therefore, corrections that take into account the detector sensitivity measured with an incoherent standard sample (Plexiglas) must be always applied to the raw data ( figure 2b). ...
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Citations
... The heating stages and temperatures presented for SANS and neutron diffraction are explained in more detail in the corresponding Section 3, Results and Discussion. Our SANS experiments presented in this paper were conducted at the KWS-2 beam line Radulescu et al. (2012) operated by Jülich Centre for Neutron Science at the FRM-II reactor, Heinz-Maier-Leibnitz Zentrum (MLZ), Garching. Two sample-to-detector distances of 2 and 8 m have been used to obtain a Q-range of 0.006 < Q < 0.3 Å −1 with a wavelength of 4.97 Å and 8 × 8 mm 2 sample aperture. ...
The design of suitable and efficient membranes for fuel and electrolyzer cells has been a long standing problem that still seeks for technical improvements. The structural properties of proton conducting poly [2,2-(m-phenylene)-5,5-bibenzimidazole] (PBI) membranes doped with phosphoric acid as electrolyte have been investigated prior and after thermal treatment by small angle neutron scattering (SANS), neutron diffraction with polarization analysis and transmission electron microscopy (TEM). Our observations indicate that during the first heating attempt stable crystalline domains in the PBI are formed and they persist in all further thermal cycles typical for electrolyte membrane operation. The combination of real space TEM picture under cryogenic conditions and reciprocal space scattering pattern with enhanced contrast by partial deuteration allows obtaining unique insight into the structure of proton conducting membranes, i.e., characteristic distances associated with irreversible changes as well as volume fraction of the different phases of the sample.
... Dispersions for the contrast variation measurements were prepared as indicated in Section 2.2, at different DMF/DMF-d7 combinations, and the list of the sample sets is given in Table 3. Solutions of the block copolymer without MWCNTs, at the same concentration and contrast, were used as references for the scattering measurements of MWCNTs dispersions (for background subtraction). The SLDs of the solvents in the various DMF/DMF-d7 mixtures are listed in Table 4. SANS measurements were carried out on the KWS-2 beamline at the FRM-2 research reactor, at the Jülich Center for Neutron Science, Outstation at the Heinz Maier-Leibnitz Zentrum, Garching, Germany [66,67]. The samples were studied in quartz cuvettes of 1 and 2 mm thickness at temperature of 25 • C. The experiments were carried out at 2, 8, and 20 m sample to detector distances at wavelength (λ) of 5 Å, with a wavelength spread δλ/λ = 20%, and a sample aperture of 8 × 8 mm. ...
This research aims to characterize the adsorption morphology of block copolymer dispersants of the styrene-block-4-vinylpyridine family (S4VP) on the surface of multi-walled carbon nanotubes (MWCNT) in a polar organic solvent, N,N-dimethyl formamide (DMF). Good, unagglomerated dispersion is important in several applications such as fabricating CNT nanocomposites in a polymer film for electronic or optical devices. Small-angle neutron scattering (SANS) measurements, using the contrast variation (CV) method, are used to evaluate the density and extension of the polymer chains adsorbed on the nanotube surface, which can yield insight into the means of successful dispersion. The results show that the block copolymers adsorb onto the MWCNT surface as a continuous coverage of low polymer concentration. Poly(styrene) (PS) blocks adsorb more tightly, forming a 20 Å layer containing about 6 wt.% PS, whereas poly(4-vinylpyridine) (P4VP) blocks emanate into the solvent, forming a thicker shell (totaling 110 Å in radius) but of very dilute (<1 wt%) polymer concentration. This indicates strong chain extension. Increasing the PS molecular weight increases the thickness of the adsorbed layer but decreases the overall polymer concentration within it. These results are relevant for the ability of dispersed CNTs to form a strong interface with matrix polymers in composites, due to the extension of the 4VP chains allowing for entanglement with matrix chains. The sparse polymer coverage of the CNT surface may provide sufficient space to form CNT-CNT contacts in processed films and composites, which are important for electrical or thermal conductivity.
... SANS measurements were performed using a KWS-2 SANS diffractometer operated by the Juelich Centre for Neutron Science at the neutron source Heinz Maier-Leibnitz (FRM II reactor) in Garching, Germany. 35 The incident neutron beam at KWS-2 was monochromatized using a velocity selector to have an average wavelength (λ) of 5 Å with a wavelength resolution of Δλ/λ = 20%. Before the SANS experiments, ETFE-g-PSSA membranes were equilibrated in a water mixture with a prescribed H 2 O/D 2 O ratio at room temperature for 24 h. ...
... The structure of MBP was investigated with SAXS and SANS: X-ray scattering experiments were performed using a lab-based Ganesha SAXS instrument (Xenocs, Grenoble, France) located at JCNS-1/IBI-8, FZJ, Jülich, Germany and SANS was measured on the small-angle neutron diffractometer KWS-2 located at MLZ, Garching, Germany [35][36][37]. Selected SAXS form factors ( )/ at a protein concentration of c = 0.5% w/v are shown in Figure 2A (see Figure S1 for SAXS data of all GndCl concentrations and Figure S2 for SANS data). In general, SAXS data of MBP are comparatively noisy for GndCl concentrations of 4 M and 6 M. ...
... The structure of MBP was investigated with SAXS and SANS: X-ray scattering experiments were performed using a lab-based Ganesha SAXS instrument (Xenocs, Grenoble, France) located at JCNS-1/IBI-8, FZJ, Jülich, Germany and SANS was measured on the small-angle neutron diffractometer KWS-2 located at MLZ, Garching, Germany [35][36][37]. Selected SAXS form factors I(q)/c at a protein concentration of c = 0.5% w/v are shown in Figure 2A (see Figure S1 for SAXS data of all GndCl concentrations and Figure S2 for SANS data). In general, SAXS data of MBP are comparatively noisy for GndCl concentrations of 4 M and 6 M. ...
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Myelin basic protein (MBP) is intrinsically disordered in solution and is considered as a conformationally flexible biomacromolecule. Here, we present a study on perturbation of MBP structure and dynamics by the denaturant guanidinium chloride (GndCl) using small-angle scattering and neutron spin–echo spectroscopy (NSE). A concentration of 0.2 M GndCl causes charge screening in MBP resulting in a compact, but still disordered protein conformation, while GndCl concentrations above 1 M lead to structural expansion and swelling of MBP. NSE data of MBP were analyzed using the Zimm model with internal friction (ZIF) and normal mode (NM) analysis. A significant contribution of internal friction was found in compact states of MBP that approaches a non-vanishing internal friction relaxation time of approximately 40 ns at high GndCl concentrations. NM analysis demonstrates that the relaxation rates of internal modes of MBP remain unaffected by GndCl, while structural expansion due to GndCl results in increased amplitudes of internal motions. Within the model of the Brownian oscillator our observations can be rationalized by a loss of friction within the protein due to structural expansion. Our study highlights the intimate coupling of structural and dynamical plasticity of MBP, and its fundamental difference to the behavior of ideal polymers in solution.
... Small-angle neutron scattering (SANS) is a powerful technique that yields important low-resolution structural information on macromolecular systems. The small-angle neutron diffractometer, KWS-2 [1], operated by the Jülich Centre for Neutron Science (JCNS) at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany, is dedicated to the investigation of mesoscopic multi-scale structures and structural changes in soft condensed matter and biophysical systems. Following demands from the user community, it was recently considerably upgraded to boost its performance with respect to the intensity on the sample, instrumental resolution, counting rate capabilities, and maximum Q-range (Q = (4π/λ)sinθ is the momentum transfer, where λ is the neutron wavelength and 2θ is the scattering angle). ...
... Small-angle neutron scattering (SANS) experiments were performed using the KWS-2 instrument at the JCNS at MLZ in Garching, Germany [1]. The measurements were typically performed using sample-to-detector distances of 1.5, 8, and 20 m, and neutron λ of 5 and 10 Å (Δλ/λ = 10%), to achieve a maximum dynamic q-range of 1 × 10 −3 -0.7 Å −1 . ...
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Understanding soft and biological materials requires global knowledge of their microstructural features from elementary units at the nm scale up to larger complex aggregates in the micrometer range. Such a wide range of scale can be explored using the KWS-2 small-angle neutron (SANS) diffractometer. Additional information obtained by in situ complementary techniques sometimes supports the SANS analysis of systems undergoing structural modifications under external stimuli or which are stable only for short times. Observations at the local molecular level structure and conformation assists with an unambiguous interpretation of the SANS data using appropriate structural models, while monitoring of the sample condition during the SANS investigation ensures the sample stability and desired composition and chemical conditions. Thus, we equipped the KWS-2 with complementary light absorption and scattering capabilities: Fourier transform infrared (FTIR) spectroscopy can now be performed simultaneously with standard and time-resolved SANS, while in situ dynamic light scattering (DLS) became available for routine experiments, which enables the observation of either changes in the sample composition, due to sedimentation effects, or in size of morphologies, due to aggregation processes. The performance of each setup is demonstrated here using systems representative of those typically investigated on this beamline and benchmarked to studies performed offline.
... SANS measurements were performed on a KWS-2 SANS diffractometer operated by Juelich Centre for Neutron Science at the neutron source Heinz Maier−Leibnitz (FRM II reactor) in Garching, Germany. 25 The incident neutron beam at KWS-2 was monochromatized with a velocity selector to have an average wavelength (λ) of 5 Å with a wavelength resolution of Δλ/λ = 20%. The scattering patterns were collected using a two-dimensional (2D) scintillation detector and circularly averaged to obtain scattering intensity profiles as a function of q, where q is the scattering vector and defined as q = (4 π/λ)sin(θ/2), where θ is the scattering angle. ...
... GISANS experiments were performed on KWS-1 [37,38] and KWS-2 [39,40] smallangle neutron scattering instruments operated by Jülich Centre for Neutron Science at Maier-Leibnitz Zentrum (Garching, Germany). ...
Grazing incidence small-angle neutron scattering (GISANS) provides access to interfacial properties, e.g., in soft matter on polymers adsorbed at a solid substrate. Simulations in the frame of the distorted wave Born approximation using the BornAgain software allow to understand and quantify the scattering pattern above and below the sample horizon, in reflection and transmission, respectively. The small-angle scattering from the interfacial layer, visible around the transmitted beam, which might contribute also on the side of the reflected beam, can be understood in this way and be included into the analysis. Background reduction by optimized sample cell design is supported by simulations, paving the way for an optimized GISANS cell.
... SANS measurements were performed at the KWS-2 beamline [35] at Maier-Leibnitz Zentrum in Garching (Garching, Germany) on the Syl-IPN and Sqr-IPN series of samples. Samples were measured at four instrument configurations to cover a wide Q range. ...
By introducing hydrophilic polymers into silicone medical devices, highly beneficial biomedical properties can be realized. An established solution to introduce hydrophilic polymers is to form an interpenetrating polymer network (IPN) byperforming the hydrogel synthesis in the presence of silicone swollen in supercritical carbon dioxide. The precise distribution of the two polymers was unknown, and determining this is the goal of this study. Neutron scattering and microscopy were used to determine the distribution of the hydrophilic guest polymer. Atomic force microscopy revealed that the important length scale on the surface of these materials is 10–100 nm, and spin-echo small-angle neutron scattering (SESANS) on IPNs submerged in D2O revealed structures of the same scale within the interior and enabled quantification of their size. SESANS with hydration by D2O proved to be the only scattering technique that could determine the structure of the bulk of these types of materials, and it should be used an important tool for characterizing polymer medical devices.
... SANS measurements of the samples of Mannan P.arc and Mannan Yeast were performed with the KWS2 instrument located at the Heinz Meier Leibtnitz Source, Garching Forschungszentrum (Germany). 31 Neutrons with a wavelength spread Δλ/λ ≤ 0.2 were used. A two-dimensional array detector at different wavelength, collimation, sample-to-detector distance combinations measured neutrons scattered from the samples. ...
Extracellular polysaccharides are widely produced by bacteria, yeasts, and algae. These polymers are involved in several biological functions, such as bacteria adhesion to surface and biofilm formation, ion sequestering, protection from desiccation, and cryoprotection. The chemical characterization of these polymers is the starting point for obtaining relationships between their structures and their various functions. While this fundamental correlation is well reported and studied for the proteins, for the polysaccharides, this relationship is less intuitive. In this paper, we elucidate the chemical structure and conformational studies of a mannan exopolysaccharide from the permafrost isolated bacterium Psychrobacter arcticus strain 273-4. The mannan from the cold-adapted bacterium was compared with its dephosphorylated derivative and the commercial product from Saccharomyces cerevisiae. Starting from the chemical structure, we explored a new approach to deepen the study of the structure/activity relationship. A pool of physicochemical techniques, ranging from small-angle neutron scattering (SANS) and dynamic and static light scattering (DLS and SLS, respectively) to circular dichroism (CD) and cryo-transmission electron microscopy (cryo-TEM), have been used. Finally, the ice recrystallization inhibition activity of the polysaccharides was explored. The experimental evidence suggests that the mannan exopolysaccharide from P. arcticus bacterium has an efficient interaction with the water molecules, and it is structurally characterized by rigid-rod regions assuming a 14-helix-type conformation.
... SANS measurements were performed using the KWS-2 instrument operated by the Jülich Centre for Neutron Science (JCNS) at Forschungs-Neutronenquelle, Heinz Maier-Leibnitz. 55 The measurements were performed at three different sample-to-detector distances, that is, 2, 8, and 20 m, and two neutron wavelengths, l = 5 Å and 10 Å, with a wavelength resolution of 10%. These configurations cover the scattering vector (q) range of 0.00133 < q (Å À1 ) < 0.411. ...
Lipid nanoparticles (LNPs) are the most clinically advanced delivery system for RNA-based drugs but have predominantly been investigated for intravenous and intramuscular administration. Subcutaneous administration opens the possibility of patient self-administration and hence long-term chronic treatment that could enable mRNA to be used as a novel modality for protein replacement or regenerative therapies. Here, we show that subcutaneous administration of mRNA formulated within LNPs can result in measurable plasma exposure of a secreted protein. However, subcutaneous administration of mRNA formulated within LNPs was observed to be associated with dose-limiting inflammatory responses. To overcome this limitation, we investigated the concept of incorporating aliphatic ester prodrugs of anti-inflammatory steroids within LNPs i.e. functionalized LNPs to suppress the inflammatory response. We show that the effectiveness of this approach depends on the alkyl chain length of the ester prodrug which determines its retention at the site of administration. An unexpected additional benefit to this approach is the prolongation observed in duration of protein expression. Our results demonstrate that subcutaneous administration of mRNA formulated in functionalized LNPs is a viable approach to achieving systemic levels of therapeutic proteins, which has the added benefits of being amenable to self-administration when chronic treatment is required.
