Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene--(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and ,-dimethylformamide, and the triblock terpolymer poly(isoprene--styrene--(4-vinyl)pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers.
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http://dx.doi.org/10.1021/mz300100b | DOI Listing |
Environ Sci Technol
January 2025
Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States.
Supercritical (sc) CO in geologic carbon sequestration (GCS) can chemically and mechanically deteriorate wellbore cement, raising concerns for long-term operations. In contrast to the conventional view of "sulfate attack" on cement, we found that adding 0.15 M sulfate to the acidic brine can significantly reduce the impact of scCO attack on Portland cement, resulting in stronger cement than that found in a sulfate-free system.
View Article and Find Full Text PDFNature
January 2025
Case Comprehensive Cancer Center and Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
The oestrogen receptor (ER or ERα), a nuclear hormone receptor that drives most breast cancer, is commonly activated by phosphorylation at serine 118 within its intrinsically disordered N-terminal transactivation domain. Although this modification enables oestrogen-independent ER function, its mechanism has remained unclear despite ongoing clinical trials of kinase inhibitors targeting this region. By integration of small-angle X-ray scattering and nuclear magnetic resonance spectroscopy with functional studies, we show that serine 118 phosphorylation triggers an unexpected expansion of the disordered domain and disrupts specific hydrophobic clustering between two aromatic-rich regions.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark; Center for Biopharmaceuticals and Biobarriers in Drug Delivery, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark. Electronic address:
Ion-protein interactions regulate biological processes and are the basis of key strategies of modulating protein phase diagrams and stability in drug development. Here, we report the mechanisms by which H-bonds and electrostatic interactions in ion-protein systems determine phase separation and amyloid formation. Using microscopy, small-angle X-ray scattering, circular dichroism and atomistic molecular dynamics (MD) simulations, we found that anions specifically interacting with insulin induced phase separation by neutralising the protein charge and forming H-bond bridges between insulin molecules.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Advanced Interdisciplinary Institute of Environment and Ecology, Guangdong Provincial Key Laboratory of Wastewater Information Analysis and Early Warning, Beijing Normal University, Zhuhai 519087, P.R.China.
Chinese herbal medicine has offered a great treasure for discovering intrinsically bioactive low molecular weight gelators (LMWGs). Herein, the two-component hydrogels comprising glycyrrhizic acid (GA) and puerarin (PUE), the primary bioactive components, respectively, from herbs and are successfully prepared. Combined spectroscopic characterizations reveal that hydrogen bonds are formed between GA and PUE molecules, which further drives the growth of nanofiber assemblies into gel networks.
View Article and Find Full Text PDFWhile novel deep learning and statistics-based techniques predict accurate structural models for proteins and non-coding RNA, describing their macromolecular conformations in solution is still challenging. Small-angle X-ray scattering (SAXS) in solution is an efficient technique to validate structural predictions by comparing the experimental SAXS profile with those calculated from predicted structures. There are two main challenges in comparing SAXS profiles to RNA structures: the structures often lack cations necessary for stability and charge neutralization, and a single structure inadequately represents the conformational plasticity of RNA.
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