Synthesis and In Situ Thermal Induction of ß-Sheet Nanocrystals in Spider Silk-Inspired Copolypeptides.

Spider silk, known for its exceptional tensile strength, extensibility, and toughness, continues to inspire advancements in polymer and materials science. Despite extensive research, synthesizing materials that encompass all these properties remains a significant challenge. This study addresses this challenge by developing high molecular-weight multiblock synthetic copolypeptides that mimic the hierarchical structure and mechanical properties of spider silk. Using autoaccelerated ring-opening polymerization of N-carboxyanhydrides, we synthesized copolypeptides featuring transformable ß-sheet blocks. These blocks retain a helical structure during synthesis but transition into ß-sheet nanocrystals in situ during solvent-free thermal mechanical processing. Compression molding was employed to induce hierarchical ordering within the copolypeptide films, resulting in a solid "liquid crystalline" structure that undergoes a temperature-induced α-to-ß structural transformation. This transformation integrates ß-sheet nanocrystals throughout the helical block matrix, significantly enhancing the material's mechanical performance. Our innovative synthesis and processing strategy, which involves alternating sequences of α-helical and ß-sheet blocks with various ß-sheet-forming NCAs, enables the customization of diverse mechanical characteristics. These advancements not only deepen our understanding of the fundamental design principles of spider silk but also pave the way for a new generation of high-performance, silk-inspired synthetic copolypeptides with broad application potential.

Tailoring Synthetic Polypeptide Design for Directed Fibril Superstructure Formation and Enhanced Hydrogel Properties.

The biological significance of self-assembled protein filament networks and their unique mechanical properties have sparked interest in the development of synthetic filament networks that mimic these attributes. Building on the recent advancement of autoaccelerated ring-opening polymerization of amino acid N-carboxyanhydrides (NCAs), this study strategically explores a series of random copolymers comprising multiple amino acids, aiming to elucidate the core principles governing gelation pathways of these purpose-designed copolypeptides. Utilizing glutamate (Glu) as the primary component of copolypeptides, two targeted pathways were pursued: first, achieving a fast fibrillation rate with lower interaction potential using serine (Ser) as a comonomer, facilitating the creation of homogeneous fibril networks; and second, creating more rigid networks of fibril clusters by incorporating alanine (Ala) and valine (Val) as comonomers. The selection of amino acids played a pivotal role in steering both the morphology of fibril superstructures and their assembly kinetics, subsequently determining their potential to form sample-spanning networks. Importantly, the viscoelastic properties of the resulting supramolecular hydrogels can be tailored according to the specific copolypeptide composition through modulations in filament densities and lengths. The findings enhance our understanding of directed self-assembly in high molecular weight synthetic copolypeptides, offering valuable insights for the development of synthetic fibrous networks and biomimetic supramolecular materials with custom-designed properties.

[Effect of Zhulian needle insertion by slow twirling technique on peroxidation and apoptosis of kidney tissue in aging rats].

OBJECTIVE: To observe the effect of Zhulian needle insertion by slow twirling technique on the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) and apoptosis rate in kidney tissue of aging model rats and explore the potential mechanism of such needling technique. METHODS: A total of 40 adult male SD rats were randomized into a blank control group, a model control group, a Zhulian needling technique group and a routine acupuncture group, 10 rats in each one. Except the blank control group, the sub-acute aging rat models were established by intraperitoneal injection with 10% D-galactose solution, 5 mL/kg in the rats of the other groups. In the Zhulian needling technique group and the routine acupuncture group, Zhulian needle insertion by slow twirling technique and the routine acupuncture technique were exerted at "Guanyuan" (CV 4) and "Zusanli" (ST 36) respectively. The needles were retained for 30 min, once a day, for 28 days totally. After intervention, the content of H2O2 in kidney tissue was detected by colorimetry, the content of MDA in kidney tissue was detected by thiobarbituric acid method and the apoptosis rate of kidney cells was detected by terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling. RESULTS: Compared with the blank control group, the contents of H2O2 and MDA in kidney tissue and kidney cell apoptosis rate were all increased in the model control group (P<0.05). Compared with the model control group, the contents of H2O2 and MDA in kidney tissue and kidney cell apoptosis rate were all reduced in the Zhulian needling technique group and the routine acupuncture group (P<0.05), and these indexes in the Zhulian needling technique group were all lower than the routine acupuncture group (P<0.05). CONCLUSION: Zhulian needle insertion by slow twirling technique delays aging probably by regulating peroxidation and apoptosis.

A circular economy approach to green energy: Wind turbine, waste, and material recovery.

Wind energy has been considered as one of the greenest renewable energy sources over the last two decades. However, attention is turning to reducing the possible environmental impacts from this sector. We argue that wind energy would not be effectively "green" if anthropogenic materials are not given attention in a responsible manner. Using the concept of the circular economy, this paper considers how anthropogenic materials in the form of carbon fibers can reenter the circular economy system at the highest possible quality. This paper first investigates the viability of a carbon-fiber-reinforced polymer extraction process using thermal pyrolysis to recalibrate the maximum carbon fiber value by examining the effect of (a) heating rate, (b) temperature, and (c) inert gas flow rate on char yield. With cleaner and higher quality recovered carbon fibers, this paper discusses the economic preconditions for the takeoff and growth of the industry and recommends the reuse of extracted carbon fibers to close the circular economy loop.