Stretchable structural colors with polarization dependence using lithium niobate metasurfaces.

Independently tunable biaxial color pixels, composed of isolated nanosquare dimers, are demonstrated in this study. These pixels are capable of displaying a full range of colors under a linear-polarization dependent reflection mode. The metasurface is constructed by arranging LiNbO3 nanodimers on a PDMS substrate. By exciting a strong magnetic dipole (MD) resonance and effectively suppressing other multipolar resonances using surface lattice resonances, the researchers achieved a single reflection peak with a bandwidth of less than 9 nm and a reflective efficiency of up to 99%. Additionally, the stretchability of the PDMS substrate allows for active and continuous tuning of the metasurface by up to 40% strain, covering almost 150 nm of the visible light spectrum and enabling changes in reflection color. This metasurface holds potential applications in various fields, such as color displays, data storage, and anti-counterfeiting technologies.

3D Printed All-Natural Hydrogels: Flame-Retardant Materials Toward Attaining Green Sustainability.

Biomass-based hydrogel is a promising flame-retardant material and has a high potential for applications in transportation, aerospace, building and electrical engineering, and electronics. However, rapid vat photopolymerization (VP) 3D printing of biomass-based hydrogels, especially that of all-natural ones, is still rare. Herein, a new class of VP 3D-printed hydrogels with strong covalent networks, fabricating using fully biomass materials and a commercial liquid crystal display (LCD) printer assembled with low-intensity visible light is presented. Encouragingly, the highly ordered layer-by-layer packing structures provided by VP 3D printing technology endow these hydrogels with remarkable flame retardancy, exceptional temperature resistance, advantageous combustion behaviors, and favorable mechanical strength, in particular, giving them a better limit oxygen index (83.5%) than various biomass-based hydrogels. The proposed approach enables the green design as well as the precise and efficient preparation for flame-retardant materials, paving the way for the future flame-retardant materials toward attaining green sustainability.

Investigation on the Preparation and Properties of CMC/magadiite Nacre-Like Nanocomposite Films.

The layered hydrated sodium salt-magadiite (MAG), which has special interpenetrating petals structure, was used as a functional filler to slowly self-assemble with sodium carboxy-methylcellulose (CMC), in order to prepare nacre-like nanocomposite film by solvent evaporation method. The structure of prepared nacre-like nanocomposite film was characterized by Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) analysis; whereas, it was indicated that CMC macromolecules were inserted between the layers of MAG to increase the layer spacing of MAG by forming an interpenetrating petals structure; in the meantime, the addition of MAG improved the thermal stability of CMC. The tensile strength of CMC/MAG was significantly improved compared with pure CMC. The tensile strength of CMC/MAG reached the maximum value at 1.71 MPa when the MAG content was 20%, to maintaining high transparency. Due to the high content of inorganic filler, the flame retarding performance and the thermal stability were also brilliant; hence, the great biocompatibility and excellent mechanical properties of the bionic nanocomposite films with the unique interpenetrating petals structure provided a great probability for these original composites to be widely applied in material research, such as tissue engineering in biomedical research.

Effects of aspartic acid and potassium chloride on arginine kinase from shrimp.

The aspartic acid (Asp)-induced unfolding and the salt-induced folding of arginine kinase (AK) were studied in terms of enzyme activity, intrinsic fluorescence emission spectra, 1-anilino-8-naphthalenesulfonate (ANS) fluorescence spectra and far-UV circular dichroism (CD) spectra. The results showed that Asp caused inactivation and unfolding of AK with no aggregation during AK denaturation. The unfolding of the whole molecule and the inactivation of AK in different Asp concentrations were compared. Much lower Asp concentration was required to induce inactivation than to produce significant conformational changes of the enzyme molecule. However, with further addition of Asp, the molar ellipticity at 222 and 208 nm, the wavelength shift and the emission intensity of ANS hardly changed. Asp denatured AK was reactivated by dilution. In addition, potassium chloride (KCl) induced the molten globule state with a compact structure after AK was denatured with 7.5 mM Asp. These results collectively elucidate the osmotic effect of Asp anions for the molten globule formed during unfolding process. They also suggest that the effect of Asp differed from that of other denaturants such as guanidine hydrochloride or urea during AK folding. The molten globule state indicates that intermediates exist during AK folding.

[Study on chitosan and PHBHHx used as nerve regeneration conduit material].

Both Chitosan and PHBHHx are natural, biodegradable biomedical materials. In this article, their ability to be made as nerve regeneration conduits are evaluated by studying their wettability, changes of the second structure of protein absorbed on their surface, growing status of fetal rat cerebral cortex nerve cells cultured on them, mechanical properties and ability to be processed later. The results indicate that both Chitosan and PHBHHx are promising nerve conduit materials.

Performance modification of chitosan membranes induced by gamma irradiation.

Trauma of the nervous system often results in permanent functional loss because the spontaneous regeneration of nerves is very difficult. Thus, various methods have been developed to facilitate the restoration of damaged nerve. The biodegradable nerve conduit is one of the most promising methods for nerve regeneration. Chitosan, a natural polysaccharide that has excellent biocompatibility and biodegradability, can be used as conduit material. But, nerves regenerated by nerve conduits made from chitosan have some problems, for example, with their mechanical properties. This article shows that the mechanical properties of chitosan film were markedly improved by selected doses of gamma radiation and cell culturing experiments on the surface of the irradiated chitosan film indicated that the film still has excellent biocompatibility.