The development of on-demand cross-linking strategies is a key aspect in promoting mechanical properties of high-performance bioinspired nanocomposites. Here, we embed styrene sulfonyl azide groups with latent chemical reactivity into water-soluble copolymers and assemble those with high-aspect-ratio synthetic nanoclays to generate well-defined layered polymer/nanoclay nacre-mimetics. A considerable stiffening and strengthening occurs upon activation of the covalent cross-linking using simple heating.
View Article and Find Full Text PDFThis paper proposes a general finite element method (FEM)-based wavenumber domain analysis (WDA) to calculate scattering characteristics of surface acoustic wave (SAW) on arbitrary piezoelectric substrates. We add a damping loss mechanism (DLM) to the SAW injection port to avoid interferences from the incident and backscattered modes. After checking the validity of the proposed method, we calculate and study Sezawa mode scattering using a small number of electrodes on the ScAlN/3CSiC structure for demonstration.
View Article and Find Full Text PDFHierarchically structured materials comprising rod-like, chiral, nanoparticles are commonly encountered in nature as they can form assemblies with exceptional optical and mechanical characteristics. These include cellulose nanocrystals (CNCs), which have a large potential for the fabrication of bioinspired materials mimicking those advanced properties. Fine-tuning the optomechanical properties of assemblies obtained from CNCs hinges on the transformations from suspensions of liquid crystals to long-range order in the dry state.
View Article and Find Full Text PDFWe present an approach to construct biocompatible and photoluminescent hybrid materials comprised of carbon quantum dots (CQDs) and TEMPO-oxidized cellulose nanocrystals (TO-CNCs). First, the amino-functionalized carbon quantum dots (NH-CQDs) were synthesized using a simple microwave method, and the TO-CNCs were prepared by hydrochloric acid (HCl) hydrolysis followed by TEMPO-mediated oxidation. The conjugation of NH-CQDs and TO-CNCs was conducted via carbodiimide-assisted coupling chemistry.
View Article and Find Full Text PDFWe present an efficient approach to develop cellulose nanocrystal (CNC) hybrids with magnetically responsive FeO nanoparticles that were synthesized using the (Fe/Fe) coprecipitation. After 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-catalyzed oxidation of CNC, carbodiimide (EDC/NHS) was used for coupling amine-containing iron oxide nanoparticles that were achieved by dopamine ligand exchange (NH-FeO NPs). The as-prepared hybrids (FeO@CNC) were further complexed with Cu(II) ions to produce specific protein binding sites.
View Article and Find Full Text PDFFilms comprising nanofibrillated cellulose (NFC) are suitable substrates for flexible devices in analytical, sensor, diagnostic, and display technologies. However, some major challenges in such developments include their high moisture sensitivity and the complexity of current methods available for functionalization and patterning. In this work, we present a facile process for tailoring the surface wettability and functionality of NFC films by a fast and versatile approach.
View Article and Find Full Text PDFTo endow percutaneous implants with improved skin integration and antibacterial activity, microporous TiO coatings doped with different doses of Cu (0-1.93 wt%) were directly fabricated on Ti via micro-arc oxidation (MAO). The structures of coatings were investigated; the adhesion, proliferation, phenotype, differentiation and extracellular collagen secretion of fibroblasts, as well as the response of Staphylococcus aureus (S.
View Article and Find Full Text PDFPolymorphic and morphological transformations of cellulosic materials are strongly associated to their properties and applications, especially in the case of emerging nanocelluloses. Related changes that take place upon treatment of cellulose nanocrystals (CNC) in alkaline conditions are studied here by XRD, TEM, AFM, and other techniques. The results indicate polymorphic transformation of CNC proceeds gradually in a certain range of alkali concentrations, i.
View Article and Find Full Text PDFPsoriasin (S100A7) is one of the members in the S100 protein family. It was first discovered as a protein abundantly expressed in psoriatic keratinocytes. Psoriasin has been implicated in a wide range of intracellular and extracellular functions, including regulation of calcium homeostasis, cell proliferation, differentiation, apoptosis, cell invasion and motility, cytoskeleton dynamics, protein phosphorylation, regulation of transcriptional factors, immune responses, chemotaxis, inflammation and pluripotency.
View Article and Find Full Text PDFObjective: To explore the effect of vitamin D analogs regulated mice urinary output on depressed expression of renin-angiotensin in paraventricular nucleus.
Methods: A total of 51 C57BL/6 mice were randomly divided into control (n = 36) and vitamin D receptor knockout (VDR, n = 15) groups. Then the tests of water deprivation, vitamin D analogue injection and 0.
Films and hydrogels consisting of cellulose nanofibrils (CNF) were modified by covalent EDC/NHS coupling of luminescent, water-dispersible carbon dots (CDs). Quartz crystal microgravimetry with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR) were used to investigate the attachment of CDs on carboxymethylated CNF (CM-CNF). As the first reported use of CD in nanocellulose products, we provide proof-of-concept for the synthesis of transparent and fluorescent nanopaper and for its tunable luminescence as confirmed by confocal microscopy imaging.
View Article and Find Full Text PDFTo gain an atomistic-level understanding on physical and chemical processes occurring at the interfaces of hypergolic propellants, we carried out the first reactive dynamic (ReaxFF) simulations to study the reactive hypergolic mixture of monomethylhydrazine (MMH) and dinitrogen tetroxide (NTO), in comparison with the ethanol (EtOH) and NTO mixture that is reactive but nonhypergolic. Our studies show that the MMH-NTO mixture releases energy more rapidly than the EtOH-NTO mixture upon mixing the fuels and oxidizers. We found that the major early chemical reactions between MMH and NTO are hydrogen abstractions and N-N bond scissions.
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