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The viscosities of three sodium carboxymethylcellulose samples with molecular weights of 90,000 [degree of substitution (DS): 0.7], 250,000 (DS: 0.9), and 700,000 (DS: 0.9) have been reported in water and methanol-water mixtures in salt-free and salt-containing solutions at 35 °C. The results were analyzed in terms of a phenomenological approach for the viscosity of polymer solutions to determine the intrinsic viscosities [η] of the polyelectrolyte samples. This contribution presents a new and convenient method for the determination of the root-mean-square radii of gyration of the polyion chains using the [η] values obtained as a function of the added salt concentration. The polyion coils are found to expand at low ionic strength and these collapse drastically with increasing ionic strength. Addition of methanol to the medium in which these samples are dissolved causes a contraction of the polyion chains, although this influence is less pronounced than that of the added salt.
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http://dx.doi.org/10.1016/j.carbpol.2013.08.019 | DOI Listing |
Int J Mol Sci
August 2025
Facultad de Ingeniería, Universidad Panamericana, Augusto Rodin No. 498, Insurgentes Mixcoac, Benito Juárez, Ciudad de México 03920, Mexico.
Hormone-dependent breast cancer, particularly in its treatment-resistant forms, remains a significant therapeutic challenge. In this study, we applied a fully computational strategy to design steroid-based compounds capable of simultaneously targeting three key receptors involved in disease progression: progesterone receptor (PR), estrogen receptor alpha (ER-α), and HER2. Using a robust 3D-QSAR model (R = 0.
View Article and Find Full Text PDFbioRxiv
July 2025
Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, 66123, Germany.
The hydration shell is an integral part of proteins since it plays key roles for conformational transitions, molecular recognition, and enzymatic activity. While the dynamics of the hydration shell have been described by spectroscopic techniques, the structure of the hydration shell remain less understood due to the lack of hydration shell-sensitive structural probes with high spatial resolution. We combined temperature-ramp small-angle X-ray scattering (-ramp SAXS) from 255-335 K with molecular simulations to show that the hydration shells of the GB3 domain and villin headpiece are remarkably temperature-sensitive.
View Article and Find Full Text PDFJ Biomech
August 2025
Instituto de Biomecánica - IBV, Universitat Politècnica de València, edifici 9C. Camí de Vera, València s/n 46022, Spain.
Body segment inertial parameters (BSIPs) are critical for human movement analysis. However, child-specific BSIPs remains limited. This study aimed to develop regression models for BSIPs (mass, CoM-position, and moments of inertia) using 3D body scans from 688 children aged 2.
View Article and Find Full Text PDFJ Chem Phys
May 2025
Department of Mathematics and Physics, Manhattan University, 4513 Manhattan College Parkway, Riverdale, New York 10471, USA.
The properties of ideal two-dimensional star and pom-pom polymers containing 601-1263 units are investigated with a Monte Carlo growth method. The mean-square radii of gyration, various g-ratios, and scattering functions are calculated. A graph theory approach is employed to obtain exact scattering functions using a novel technique for counting paths in the graph representation of the polymers.
View Article and Find Full Text PDFSci Adv
April 2025
Department of Chemistry, University of Texas at Austin, 2506 Speedway, Austin, TX 78712, USA.
Adding nonadsorbing polymers to hard microsphere dispersions generates osmotic depletion attractions that can be quantitatively predicted and designed to manipulate colloidal phase behavior. Whether depletion described by classical theories is the mechanism for polymer-mediated nanosphere attractions is less evident. Colloidal hard nanospheres and nonadsorbing polymers are challenging to realize given the diverse interactions typically present in nanoparticle dispersions.
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