European Spallation Source

Conventional methods of pea protein extraction are resource-intensive, involving multiple purification steps that remove co-existing components such as starch. In contrast, we investigate how minimally processed yellow pea protein extracts that retain residual carbohydrates form thermally induced gels. Contrast-variation small-angle neutron scattering, rheology, and differential scanning calorimetry show that salt-extracted samples form a unified gel matrix through co-gelation of protein and carbohydrate components, as evidenced by a shared contrast match point in the final network. Ultra-small-angle neutron scattering reveals mesoscale heterogeneity, with structural features persisting up to 2 μ m, indicative of a particulate, protein-rich network within the composite gel. Rheological and calorimetric analyses suggest that gelation proceeds via a kinetic pathway in which protein aggregation precedes unfolding, ultimately shaping network architecture and viscoelastic properties. These findings demonstrate that minimal processing can yield structurally integrated protein–starch gels and clarify how composition and processing determine network architecture and mechanical performance. • We study the thermal gelation of pea protein and carbohydrates from truncated extraction. • Co-gelation is evidenced via contrast-variation small-angle neutron scattering. • Model fitting and data-driven decomposition evidence multi-scale structures. • The gelation process is further monitored by rheology and calorimetry. • Protein-carbohydrate co-gelation seems promising for sustainable protein extraction.

In 2021, neutron structures of oxidised and reduced human manganese superoxide dismutase were published, suggesting several unexpected features, including deprotonated glutamate, tyrosine and histidine residues and a reduced Mn ion with two hydroxide ligands. We have used quantum refinement to evaluate whether alternative interpretations of the structures are possible, comparing many structural models with different possible protonation states or other structural interpretations. Quantum refinement is standard crystallographic refinement in which the empirical restraints, which are employed to ensure that the structure makes chemical sense and gives reasonable bond lengths and angles, are replaced by quantum mechanical calculations for a small but interesting part of the structure. We show that in all cases, there are more chemically reasonable interpretations of the structures, not involving any deprotonated residues, which give slightly improved structures in terms of real-space Z scores based on the difference maps and strain energies. Weak nuclear densities do not necessarily indicate that an atom is not present; instead it may indicate that the atom may have several conformations or shows extensive dynamics. For the Tyr-34 residue, our results indicate that the phenolic hydroxide H atom should preferably be within the aromatic ring plane (by ~20 kJ/mol), but with two possible conformations. Moreover, an Mn-bound water molecule can readily accept a hydrogen bond from the nearby Gln-143 residue.

A major challenge hampering the industrial and biological exploitation of lipases is the self-limiting effect of the lipolytic reaction. Defying sustained attention throughout history, the influence of lipase catalysed lipolysis on the internal structure of thin triglyceride films has proved elusive. An in-depth understanding of the lipolysis process at the triglycerides/aqueous interface will assist in creating innovative methods to enhance yields. This study furthers our understanding of the influence of solution pD (pH equivalent for aqueous solutions prepared with D2O) on the effect of lipolysis on the structure of thin triolein films. All experiments were performed at pD 7.0 or pD 8.5, either side of the apparent pKa of the primary product of the hydrolysis (oleic acid/oleate). Spectroscopic ellipsometry measurements were employed to kinetically track the changes in thickness of the triolein film after the introduction of 2 ppm Thermomyces lanuginosus lipase (TLL). Neutron reflectometry experiments revealed the internal structure of the thin films before and after TLL digestion, while fast kinetic measurements capturing changes to the reflectivity profile throughout lipolysis. Both techniques revealed significant variations in the physical properties and enzymatic conversion of the triolein films between pD 7.0 and pD 8.5.

Clathrin assembly lymphoid myeloid leukaemia protein (CALM) is involved in the formation of clathrin-mediated endocytic coats by virtue of binding many proteins involved in the process, including clathrin itself and AP2 cargo adaptor complex. CALM is able to specifically recognize the inner leaflet of the plasma membrane by binding the membrane's phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). Here, a quantitative biophysical approach -combining neutron/X-ray scattering, solid-state NMR, atomic force microscopy, and quartz crystal microbalance with dissipationmonitoring-, was exploited to investigate CALM interaction with PtdIns(4,5)P2-presenting model membranes. The presented experimental data reveal CALM's folded domain partially embeds (12% volume occupancy) within the membrane, directly coordinating a cluster of 4 to 5 PtdIns(4,5)P2 molecules via phosphate interactions. The N-terminal amphipathic helix inserts ~8 Å into the headgroup region, reducing local membrane stiffness by 36% (from 22 to 14 MPa) while increasing viscoelastic dissipation. These results establish a plausible threefold curvature-generation mechanism: PtdIns(4,5)P2 clustering, helix insertion-induced lipid compaction and global mechanical softening-collectively lowering the energy barrier for membrane deformation.

Abstract At ESS, the cryogenic moderator system (CMS) provides subcooled liquid hydrogen with a temperature of 17.5 K to two hydrogen moderators, with plans for expansion to four in the future. The CMS removes nuclear heating, which amounts to 6.7 kW fort two moderators and 17.2 kW for four moderators during 5-MW proton beam operations. A large-scale 20 K helium refrigeration system with a cooling capacity of 30.2 kW at 15 K, called Target Moderator CryoPlant (TMCP). It is designed not only to manage a static heat load but also to effectively handle the transient heat load induced by the beam injection. To maintain the stability of the hydrogen supply temperature at 17 K, the cooling power directed toward the CMS will be adjusted by varying a feed flow rate, while the cooling power of the TMCP cold box remains constant. This study investigates the stability of TMCP thermal compensation operation when the rapid thermal fluctuations are applied. A one-dimensional simulation model of the heat exchanger was developed to simulate propagation of the thermal fluctuations resulting from the proton beam injection or trip event. Operational parameters can be optimized to minimize Vluctuations in the hydrogen supply temperature within ±0.1 K.

Abstract The European Spallation Source (ESS) is a neutron-scattering facility which will use a pulsed 2.0 GeV proton beam generated in the linear accelerator (LINAC) for releasing high-energy neutrons in the ESS target station. The 2K superconducting linac comprises 13 spoke and 30 elliptical cryomodules. The cryogenic distribution system (CDS) connects the cryogenic plant with the 43 cryomodules through a 400 meters long cryogenic multi-transfer, 43 valve boxes and an endbox. The CDS consists of 373 control valves in total. There are 8 and 10 control valves in each elliptical and spoke valve boxes, respectively, and 3 valves in the end box. The control valves are used for regulating or blocking the process helium flows. The seat tightness of the CDS valves is crucial especially for warming up individual cryomodules, which is required for potential short-term maintenance or repair activities in the cryomodule while keeping the others in cryogenic conditions. What is more, leaks over valve seats might cause moisture or ice formation on room temperature uninsulated pipes for warmup and cooldown valves or add heat load to the cryogenic system. Valve initialization and leak tightness tests were firstly performed with warm helium in the second half of 2022 before the first CDS cooldown. The tests revealed many leaks above the specified acceptable leak rate of 10-4 mbarl/s with several of them reaching even 102 mbar.l/s. The major bulk of those leaks were fixed before and after the 2nd CDS cooldown that followed in 2023. This paper describes the seat leak test method and results, as well as the possible causes of the observed leaks, the taken solutions for repairing the insufficiently tight valves and the prevention for valve seat leak.

We present the detailed design and performance simulations of BIFROST, a multiplexing indirect neutron time-of-flight spectrometer at the European Spallation Source. The instrument allows a neutron bandwidth of Δλ = 1.74 Å to reach the sample. The polychromatic flux can reach 6 × 109 n/s/cm2 while retaining a relative energy resolution, δEi/Ei, of around 3.5% at Ei = 5 meV. A fast pulse-shaping chopper allows for flexibility in the primary spectrometer resolution. For an opening time of 0.1ms, a relative energy resolution down to 0.2% is achieved for Ei = 12 meV. The secondary spectrometer consists of 45 analyzer arrays, populating 9 scattering angle channels in the horizontal scattering plane, each of which covers 5.2° in scattering angle. Each channel hosts 5 analyzer arrays reflecting neutrons of fixed energies Ef equal to 2.7, 3.2, 3.8, 4.4, and 5.0meV. Utilizing the prismatic analyzer concept, the back-end geometry allows a secondary spectrometer energy resolution in the range of 0.02-0.05meV. The unique design of BIFROST offers not only an unprecedented neutron flux but also the ability to adjust the energy resolution by more than one order of magnitude. Focusing on the horizontal scattering plane, the spectrometer is ideally suited for extreme environment studies and for studying samples much smaller than 1 cm3. The drastic increase in measurement efficiency, compared to current high-flux spectrometers, has a particularly high impact on the fields of quantum magnetism, unconventional superconductivity, and functional materials.

We investigate the link between the internal microstructure of poly(N-isopropylacrylamide)-poly(ethylene glycol) methyl ether methacrylate (PNIPAM-PEGMA) microgels, their bulk moduli and the rheological response and structural arrangement in dense suspensions. The low degree of crosslinking combined with the increased hydrophilicity induced by the presence of PEGMA results in a diffuse, star-like density profile of the particle and very low values of the bulk modulus in dilute conditions, as determined by small angle neutron scattering (SANS). The ultrasoft nature of the particle is reflected in the changes of the structural arrangement in dense suspensions, which evidence a strong deswelling and a sharp rise of the bulk modulus at moderate packing fractions. At larger packings the single particle morphology and softness saturate, and we observe a structural transition from a dispersion-like to a hydrogel-like behavior. The transition is also reflected in the rheological response in the form of a two-step yielding at large packing fractions, characteristic of systems in which a network structure is present. Our results demonstrate that a knowledge of the internal structure and mechanics of individual microgels is needed to determine and tune the properties of dense suspensions, and optimize their response for applications in biomedicine and as filtration systems.