Monovalent Ion Effect on Liquid-Liquid Phase Separation of Aqueous Polyphosphate-Salt Mixtures.

Polyphosphate (polyP) is one of the most conserved biomacromolecules and can form aggregates, such as polyP granules in bacteria, which are generated through liquid-liquid phase separation (LLPS). Studies have examined the mechanism of polyP aggregation using LLPS systems containing artificial polyP molecules as aggregation system models, where LLPS is typically induced by multivalent salts and polyelectrolytes. Although the typical concentrations of monovalent ions in living cells are approximately 100 times higher than those of divalent ions, the effects of monovalent ions on the LLPS of polyP solutions are little known.

Nacre-Inspired Nanocomposites from Natural Polypeptide ε-Poly-l-Lysine and Natural Clay Montmorillonite: Remarkable Reinforcing Effect at Low Polymer Content and Its Mechanism.

Nanocomposites composed of the cationic polypeptide ε-poly-l-lysine (ε-PL) and natural sodium montmorillonite (MMT) were prepared and evaluated. These MMT/ε-PL composites formed highly ordered nanostructures resembling natural nacreous layers by a simple process. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses confirmed that a small amount of ε-PL remarkably enhanced the MMT orientation in the composites.

Simultaneous Measurement of Two-Trace Two-Dimensional (2T2D) Near-Infrared (NIR) Asynchronous Correlation Spectra and Small-Angle X-ray Scattering (SAXS) to Characterize Thermally Aged Polypropylene (PP).

In this study, a new system was developed to carry out simultaneous near-infrared (NIR) and small-angle X-ray scattering (SAXS) measurements. Aged polypropylene (PP) was examined with the NIR-SAXS system to demonstrate how it can be utilized to derive pertinent information about the polymer structure. Pairs of SAXS profiles and NIR spectra of PP in its initial state and after aging were measured to derive an in-depth understanding of the aging phenomenon.

In Situ Raman Analysis of Biofilm Exopolysaccharides Formed in and Commensal Cultures.

This study probed in vitro the mechanisms of competition/coexistence between (known for being correlated with health in the oral cavity) and (responsible for aciduric oral environment and formation of caries) by means of quantitative Raman spectroscopy and imaging. In situ Raman assessments of live bacterial culture/coculture focusing on biofilm exopolysaccharides supported the hypothesis that both species engaged in antagonistic interactions. Experiments of simultaneous colonization always resulted in coexistence, but they also revealed fundamental alterations of the biofilm with respect to their water-insoluble glucan structure.

In Vitro Enzymatic Polymerization of α-1,6--α-1,3-glucan and Structural Analysis of Gel Formation.

α-1,6--α-1,3-glucan comprises a main-chain of α-1,6-glucan and side-chains of α-1,3-glucan. It was synthesized by a one-pot in vitro enzymatic polymerization of sucrose and dextran (α-1,6-glucan) of different molecular weights. In the presence of the high-molecular-weightdextran ( ≥ 650 000), the graft glucan formed a self-standing hydrogel without any cross-linker.