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NiCo 2 O 4 @NiMoO 4 core–shell nanowires (NCNMW) and nanosheets (NCNMS) with high electrochemical capabilities were synthesized using a simple two-step hydrothermal reaction, together with a calcination process.
Amphiphilic block copolymers possess great potential as biomaterials in drug delivery and gene therapy. Herein, pseudopeptidic‐type diblock copolymer of poly(2‐oxazoline)‐ block ‐polypeptoid (POx‐ b ‐POI) is presented and synthesized. Poly[2‐(3‐butenyl)‐2‐oxazoline]‐ block ‐poly(sarcosine) (PBuOx‐ b ‐PSar) comprising hydrophobic POx segment bearing alkenyl side chain and hydrophilic POI segment of N ‐methyl glycine, viz., sarcosine, is prepared by ring‐opening polymerization (ROP) through a one‐pot and three‐step route. Diphenyl phosphate initiates ROP of BuOx, and then the living chain end of PBuOx is quenched by ammonia to obtain PBuOx‐ammonium phosphate in situ, the active ammonium group initiates ROP of sarcosine N ‐carboxy anhydride. PBuOx‐ b ‐PSar with controlled molecular weights (4.7–10.8 kg mol −1 ) and narrow dispersities ( Ð M 1.15–1.21) are characterized by 1 H NMR, 13 C NMR, and size‐exclusion chromatography. Dynamic light scattering and transmission electron microscopy analysis reveal that PBuOx‐ b ‐PSar self‐assembles into nanostructures of average diameter D H of 37–109 nm in aqueous solution. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide test demonstrates the cytocompatibility (relative cell viability > 80%) of the PBuOx‐ b ‐PSar. In view of the self‐assembly and biocompatibility, the readily prepared diblock copolymers may hopefully be used in biomedical applications. image
An aerobic cobalt-catalyzed oxidative cyclization of 2-aminophenols and isonitriles is reported. These additive-free conditions furnish a variety of substituted 2-aminobenzoxazoles in moderate to excellent yields. A series of control experiments and spectroscopic studies point to the importance of 2-aminophenol coordination in enabling the aerobic oxidation of cobalt(II).
Rapid extraction and analysis of target molecules from irregular surfaces are in high demand in the field of on-site analysis. Herein, a flexible platform used for surface-enhanced Raman scattering (SERS) based on an ordered polymer pyramid structure with half-imbedded silver nanoparticles (AgNPs) was prepared to address this issue. The fabrication includes the following steps: (1) creating inverted pyramid arrays in silicon substrate, (2) preparing a layer of AgNPs on the surface of the inverted pyramids, and (3) obtaining a substrate with an ordered polymer pyramids array with half-imbedded AgNPs by the molding method. This flexible substrate is capable of rapid extraction via a simple and convenient "paste and peel off" method. In addition, the substrate exhibits great repeatability and good sensitivity thanks to the uniformity and larger surface area of the ordered pyramids. The density of "hot spots" (local electromagnetic field with high intensity) is increased on the structured surface. Semi-imbedding silver particles in the polymer pyramids makes "hot spots" robust on the substrate. In addition, the preprepared silicon template with the inverted pyramids can be reused, which greatly reduces the production cost. With this substrate, we successfully analyzed thiram molecules on the epidermis of apples, cucumbers, and oranges, and the detection limits are 2.4, 3, and 3 ng/cm2, respectively. These results demonstrate the great potential of the substrate for in situ analysis, which can provide reference for the design of ideal SERS substrates.
In this paper we introduce an analytical method to control the response of conformal metasurfaces with respect to an impinging plane wave as excitation source. We first develop and present the analytical framework in order to achieve a full control over the current distribution within the metasurface. Then, in order to prove the theoretical model, we design a test-case through a numerical solver, consisting in a curved magnetic metasurface excited by a plane wave. The obtained numerical results are in excellent agreement with the theory, confirming the validity of the proposed approach. In this way, an accurate and effective control over conformal magnetic metasurfaces can be accomplished, extending the possible technological applications with respect to the traditional planar configuration.
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