Neutron scattering lengths: A survey of experimental data and methods

Koester, L.; Rauch, H.; Seymann, E.

doi:10.1016/0092-640x(91)90012-s

Cited by 213 publications

(104 citation statements)

References 53 publications

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“…Here, S is the total protein surface of each protein mutant (Table S2), and r bulk are the bulk solvent (150 mM NaCl) densities for x-rays (0.3357 e À /Å 3 ) or neutrons (6.39 Â 10 10 cm À2 in 100% D 2 O), calculated from the literature (60,61). N GFPðiÞ …”

Section: Integrative Saxs/sans Data Analysismentioning

confidence: 99%

SAXS/SANS on Supercharged Proteins Reveals Residue-Specific Modifications of the Hydration Shell

Kim

Martel

Girard

et al. 2016

Biophysical Journal

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Water molecules in the immediate vicinity of biomacromolecules, including proteins, constitute a hydration layer characterized by physicochemical properties different from those of bulk water and play a vital role in the activity and stability of these structures, as well as in intermolecular interactions. Previous studies using solution scattering, crystallography, and molecular dynamics simulations have provided valuable information about the properties of these hydration shells, including modifications in density and ionic concentration. Small-angle scattering of x-rays (SAXS) and neutrons (SANS) are particularly useful and complementary techniques to study biomacromolecular hydration shells due to their sensitivity to electronic and nuclear scattering-length density fluctuations, respectively. Although several sophisticated SAXS/SANS programs have been developed recently, the impact of physicochemical surface properties on the hydration layer remains controversial, and systematic experimental data from individual biomacromolecular systems are scarce. Here, we address the impact of physicochemical surface properties on the hydration shell by a systematic SAXS/SANS study using three mutants of a single protein, green fluorescent protein (GFP), with highly variable net charge (þ36, À6, and À29). The combined analysis of our data shows that the hydration shell is locally denser in the vicinity of acidic surface residues, whereas basic and hydrophilic/hydrophobic residues only mildly modify its density. Moreover, the data demonstrate that the density modifications result from the combined effect of residue-specific recruitment of ions from the bulk in combination with water structural rearrangements in their vicinity. Finally, we find that the specific surface-charge distributions of the different GFP mutants modulate the conformational space of flexible parts of the protein.

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Section: Integrative Saxs/sans Data Analysismentioning

confidence: 99%

SAXS/SANS on Supercharged Proteins Reveals Residue-Specific Modifications of the Hydration Shell

Kim

Martel

Girard

et al. 2016

Biophysical Journal

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“…The background level for 500 ppm B sample is in between the background levels for 1000 and 150 ppm B samples. This can be explained on the basis of larger absorption of neutrons by boron in the high-boron samples [14]. The background is predominantly (84%) caused by incoherent scattering from Co atoms as they have the incoherent scattering cross section equal to 4.8 barn (compared to 0.9 barn for Re and 1.83 barn for Cr; 1 barn = 10 −24 cm −2 ) and, moreover, the element Co is the most abundant element in the studied Co-based Co-17Re-23Cr alloys (~60 at %).…”

Section: Background Intensitymentioning

confidence: 99%

Additional Phases at High Boron Content in High-Temperature Co–Re–Cr Alloys

Béran

Mukherji

Strunz

et al. 2018

Metals

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Boron largely increases the ductility of polycrystalline high-temperature Co-Re-Cr alloys. Therefore, the effect of boron addition on the alloy structural characteristics is of large importance for the stability of the alloy at operational temperatures. Along with the Co-solid solution matrix phase transformation from hcp to fcc structure, additional structural effects were observed in situ at very high temperatures (up to 1500 • C) using neutron diffraction (ND) in boron-containing Co-17Re-23Cr alloys. Increasing boron content up to 1000 wt. ppm lowers the temperature at which sublimation of Co and Cr from the matrix occurs. As a result, the composition of the matrix in the surface region is changed leading to the formation of a second and a third matrix hcp phases at high temperatures. The consideration on the lattice parameter dependence on composition was used to identify the new phases appearing at high temperatures. Energy-dispersive spectroscopy and ND results were used to estimate the amount of Co and Cr which sublimated from the surface region of the high-boron sample. In the sense of alloy development, the sublimation of Co and Cr is not critical as the temperature range where it is observed (≥1430 • C) is significantly above the foreseen operation temperature of the alloys (1200 • C).

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“…The cold neutron scattering cross section can be measured at zero angle by "optical" methods, at nonzero angles using Bragg diffraction, or over all angles by the "transmission" method giving then the total cross section [29].…”

Section: A Neutron Scatteringmentioning

confidence: 99%

Bounding quantum dark forces

2018

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Dark sectors lying beyond the Standard Model and containing sub-GeV particles which are bilinearly coupled to nucleons would induce quantum forces of the Casimir-Polder type in ordinary matter. Such new forces can be tested by a variety of experiments over many orders of magnitude. We provide a generic interpretation of these experimental searches and apply it to a sample of forces from dark scalars behaving as 1=r 3 , 1=r 5 , 1=r 7 at short range. The landscape of constraints on such quantum forces differs from the one of modified gravity with Yukawa interactions and features, in particular, strong short-distance bounds from molecular spectroscopy and neutron scattering.

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Neutron scattering lengths: A survey of experimental data and methods

Cited by 213 publications

References 53 publications

SAXS/SANS on Supercharged Proteins Reveals Residue-Specific Modifications of the Hydration Shell

SAXS/SANS on Supercharged Proteins Reveals Residue-Specific Modifications of the Hydration Shell

Additional Phases at High Boron Content in High-Temperature Co–Re–Cr Alloys

Bounding quantum dark forces

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