Self-assembled chessboard-like (CB-like) nanostructures in oxides are potential candidate materials for high density memory and energy storage devices. The evolution of CB-like nanostructures has ...been studied by combining transmission electron microscopy and 3D atom probe tomography in spinel-forming CoFeMn oxide. CB-like nanostructures evolve through a complex process of twinning, subdomain formation through recurrent pseudo-spinodal decomposition and domain coalescence along specific crystallographic axes. It initiates with the cross-penetration of compound deformation twins with subtle chemical composition separation between different domains, which ultimately results in the polymorphic transformation of cubic and tetragonal phases. The requirement of interfacial strain minimization leads to the formation of two tetragonal and two cubic spinel domains of different compositions which are rotationally orientated. In the CB-like nanostructure, cubic and tetragonal domains are connected along 〈022〉 directions. Cubic with cubic domains, and tetragonal with tetragonal domains, are connected along 〈040〉 or 〈004〉 directions. Recurring pseudo-spinodal decomposition within the CB-like domains leads to the formation of finer CB-like nanodomains. The formation of cuboid shaped domains of the cubic and tetragonal phases to rod shape morphology with four {220} and two {001} faces can give rise to 2D CB-like nanostructures. Combined transmission electron microscopy and atom probe tomography analysis indicates that CB-like nanostructures can also form in 3D, and a new model for this has been proposed based on the octahedral/cuboidal shape of the compositionally separated domains. The coalescence of such nanostructures along 〈004〉 directions gives rise to a rod-like morphology. The proposed model is expected to lead to a paradigm shift in the current understanding of CB-like nanostructures.
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Electrical properties of nanocomposites are determined by the conductive paths of carbon black and influenced by a “network” of silica. With increasing content of silica, carbon black (CB) particles ...are optimally dispersed, contributing to the generation of a conductive network between CB particles via direct particle contact and a tunneling effect; maximum conductivity for the epoxy resin–CB–silica nanocomposite described herein occurs at a ratio of 0.6:1.0 (SiO
2:CB). As a non-conductive component, excessive silica will prevent electron flow, giving rise to low conductivity.
Cord blood (CB) mononuclear cell populations have demonstrated significant promise in biomaterials-based regenerative therapies; however, the contributions of monocyte and macrophage subpopulations ...towards proper tissue healing and regeneration are not well understood, and the phenotypic responses of macrophage to microenvironmental cues have not been well-studied. In this work, we evaluated the effects of cytokine stimulation and altered substrate stiffness. Macrophage derived from CB CD14+ monocytes adopted distinct inflammatory (M1) and anti-inflammatory (M2a and M2c) phenotypes in response to cytokine stimulation (M1: lipopolysaccharide (LPS) and interferon (IFN-γ); M2a: interleukin (IL)-4 and IL-13; M2c: IL-10) as determined through expression of relevant cell surface markers and growth factors. Cytokine-induced macrophage readily altered their phenotypes upon sequential administration of different cytokine cocktails. The impact of substrate stiffness on macrophage phenotype was evaluated by seeding CB-derived macrophage on 3wt%, 6wt%, and 14wt% poly(ethylene glycol)-based hydrogels, which exhibited swollen shear moduli of 0.1, 3.4, and 10.3 kPa, respectively. Surface marker expression and cytokine production varied depending on modulus, with anti-inflammatory phenotypes increasing with elevated substrate stiffness. Integration of specific hydrogel moduli and cytokine cocktail treatments resulted in the differential regulation of macrophage phenotypic biomarkers. These data suggest that CB-derived macrophages exhibit predictable behaviors that can be directed and finely tuned by combinatorial modulation of substrate physical properties and cytokine profiles.
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Protein/peptide fibrillation is an important challenge for biotechnological drug development. Salmon calcitonin (sCT) is currently used in the clinical treatment of bone-related ...diseases such as osteoporosis and hypercalcemia, but it still has the risk of immune responses. Although human calcitonin (hCT) would be a better choice in terms of immunogenicity, it has a strong tendency to irreversibly aggregate in aqueous solutions and form long amyloid fibrils, which significantly reduces its bioavailability and therapeutic potency. Here, we demonstrate that cucurbit7uril (CB7) can inhibit hCT fibrillation by supramolecular interaction with its aromatic groups (affinity: Phe16 > Tyr12 > Phe19 > Phe22). The hCT-CB7 complex exhibits low cytotoxicity, even promotes osteoblast proliferation and osteogenic capacity of MC3T3 cells. Meanwhile the hCT-CB7 complexes shows higher bioactivity compared to hCT in reducing blood calcium levels in rats, and also decreases the immunogenicity of hCT. These results suggest that CB7 has the potential to improve the therapeutic potency of amyloidogenic protein/peptide drugs such as hCT.
This study investigates the effects of the addition of multi-walled carbon nanotubes (MWNTs) on the positive temperature coefficient (PTC) characteristics of conventional carbon black ...(CB)/high-density polyethylene (HDPE) composites. MWNT/CB/HDPE hybrid nanocomposites were prepared by the combined solution and melt-mixing process. The obtained results indicated that the PTC intensity and repeatability of the hybrid nanocomposites were dramatically improved by adding a small amount of MWNT and that the optimal MWNT content corresponded to the CB content. The initial resistivity of the materials decreased with increasing MWNT content, but not always in the PTC intensity.
