Effect of Alloying on Microstructure and Mechanical Properties of AlCoCrFeNi2.1 Eutectic High-Entropy Alloy.

In order to explore the effect of alloying on the microstructures and mechanical properties of AlCoCrFeNi2.1 eutectic high-entropy alloys (EHEAs), 0.1, 0.2, and 0.3 at.% V, Mo, and B were added to the AlCoCrFeNi2.1 alloy in this work. The effects of the elements and contents on the phase composition, microstructures, mechanical properties, and fracture mechanism were investigated. The results showed that the crystal structures of the AlCoCrFeNi2.1 EHEAs remained unchanged, and the alloys were still composed of FCC and BCC structures, whose content varied with the addition of alloying elements. After alloying, the aggregation of Co, Cr, Al, and Ni elements remained unchanged, and the V and Mo were distributed in both dendritic and interdendritic phases. The tensile strengths of the alloys all exceeded 1000 MPa when the V and Mo elements were added, and the Mo0.2 alloy had the highest tensile strength, of 1346.3 MPa, and fracture elongation, of 24.6%. The alloys with the addition of V and Mo elements showed a mixed ductile and brittle fracture, while the B-containing alloy presented a cleavage fracture. The fracture mechanism of Mo0.2 alloy is mainly crack propagation in the BCC lamellae, and the FCC dendritic lamellae exhibit the characteristics of plastic deformation.

Curcumin-Encapsulated Co-ZIF-8 for Ulcerative Colitis Therapy: ROS Scavenging and Macrophage Modulation Effects.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by the disruption of the intestinal epithelial barrier. This study described the synthesis and characterization of CCM-Co-ZIF-8, a novel composite material with enzyme-like activities similar to catalase, peroxidase, and superoxide dismutase. CCM-Co-ZIF-8 demonstrated the ability to scavenge reactive oxygen species that play a critical role in UC pathogenesis. In vitro studies using lipopolysaccharide-induced RAW264.7 cells showed that CCM-Co-ZIF-8 exhibited anti-inflammatory activity by promoting the transition of macrophages from an M1 to an M2 phenotype. In vivo experiments using a mouse model of UC demonstrated that CCM-Co-ZIF-8 suppressed the expression of proinflammatory cytokines. These findings suggested that CCM-Co-ZIF-8 might hold promise as a therapeutic strategy for the treatment of UC.

Enhanced hyaline cartilage formation and continuous osteochondral regeneration via 3D-Printed heterogeneous hydrogel with multi-crosslinking inks.

The unique gradient structure and complex composition of osteochondral tissue pose significant challenges in defect regeneration. Restoration of tissue heterogeneity while maintaining hyaline cartilage components has been a difficulty of an osteochondral tissue graft. A novel class of multi-crosslinked polysaccharide-based three-dimensional (3D) printing inks, including decellularized natural cartilage (dNC) and nano-hydroxyapatite, was designed to create a gradient scaffold with a robust interface-binding force. Herein, we report combining a dual-nozzle cross-printing technology and a gradient crosslinking method to create the scaffolds, demonstrating stable mechanical properties and heterogeneous bilayer structures. Biofunctional assessments revealed the remarkable regenerative effects of the scaffold, manifesting three orders of magnitude of mRNA upregulation during chondrogenesis and the formation of pure hyaline cartilage. Transcriptomics of the regeneration site in vivo and scaffold cell interaction tests in vitro showed that printed porous multilayer scaffolds could form the correct tissue structure for cell migration. More importantly, polysaccharides with dNC provided a hydrophilic microenvironment. The microenvironment is crucial in osteochondral regeneration because it could guide the regenerated cartilage to ensure the hyaline phenotype.

The different composites of cellulose nanocrystals with d- or l-histidine.

Cellulose nanocrystals (CNCs) are inherently right-handed nanostructures that originate from nature, showing chirality in their fibrils, bundles, and self-assembled films. However, the enantio-specific interaction between CNCs and other chiral molecules has not been explored so far. In this study, we first demonstrated a chirality-related difference in the composite films of cellulose nanocrystals and histidine with a d- or l-configuration. The distinction is not only presented in the self-assembled nanostructures of CNCs, optical properties, and the thermal decomposition of composites but also in the crystallization of the amino acid. We suppose that it might have originated from the packing of amino acids on the twisted surface of CNCs. The knowledge about the enantio-specific interaction between the chiral amino acid and polysaccharide nanostructure is of significant importance for developing a new strategy for enantiomeric separation.