Biological application of chiral nanoparticles (NPs) has aroused enormous levels of attention over recent years. Here, we synthesized magneto-chiral cobalt hydroxide (Co(OH) 2 ) NPs that exhibited strong chiroptical and unique magnetic properties and applied these NPs to detect and monitor reactive oxygen species (ROS) in living cells and in vivo. Circular dichroism (CD) and magnetic resonance imaging (MRI) signals of the magneto-chiral Co(OH) 2 NPs exhibited a wide intracellular ROS detection range from 0.673 to 612.971 pmol/10 6 cells with corresponding limits of detection (LOD) at 0.087 and 0.179 pmol/10 6 cells, far below that of currently available probes; the LOD for D-aspartic acid coated Co(OH) 2 NPs (D-Co(OH) 2 NPs) was 5.7 times lower than that for L-aspartic acid coated Co(OH) 2 NPs (L-Co(OH) 2 NPs) based on the CD signals. In addition, D-Co(OH) 2 NPs also exhibited dynamic ROS monitoring ability. The high levels of selectivity and sensitivity to ROS in complex biological environments can be attributed to the Co 2+ oxidation reaction on the surface of the NPs. Furthermore, magneto-chiral Co(OH) 2 NPs were able to quantify the levels of ROS in living mice by fluorescence and MRI signals. Collectively, these results reveal that magneto-chiral Co(OH) 2 NPs exhibit a remarkable ability to quantify ROS levels in living organisms, and could therefore provide new tools for exploring chiral nanomaterials as a potential biosensor to investigate biological events.
A composite solid polymer electrolyte
(CSPE) is studied in this
work to alleviate the concerns associated with poor mechanical strength
of a solid polymer electrolyte (SPE) system composed of poly(ethyleneglycol)diacrylate,
an electrolyte lithium bis(trifluoromethane)sulfonamide, and a plasticizer
succinonitrile. CSPE is fabricated by incorporating the ingredients
of SPE in the macroporous membranes of syndiotactic polystyrene to
render flexibility and mechanical robustness with a 6-fold increase
in tensile strength over SPE. The data from differential scanning
calorimetry and wide-angle X-ray diffraction confirm the amorphous
nature of the polymeric domains of SPE that produce high room-temperature
ionic conductivity of ∼0.43 mS/cm. The flexible CSPE membranes
are used as the electrolyte in Li-ion battery (LIB) half cells in
conjunction with lithium iron phosphate as the counter electrode.
The use of CSPE helps expand the electrochemical window of the cell
to 5 V, indicating strong potential in the fabrication of flexible
rechargeable LIBs.
A hydrodynamics method (HM) has been developed to predict the contact stresses in hot strip rolling. This method is based on that materials deformed in hot rolling present properties of viscous fluid. The contact stress formulas are derived from Navier–Stokes equation (N‐S equation) by using HM. The contact stresses predicted by these formulas agreed well with the experiment data, which verified the validity of these formulas. By comparisons of experiment data with the results predicted by the derived formulas, the Amontons–Coulomb friction model (ACM) and the Absolute constant friction model (AFM), it is found that formulas derived by HM can smooth the friction hill and has higher accuracy in predicting the neutral plane positon than the ACM and the AFM did. It is believed that the contact stress formulas derived by HM can be used to solve on line hot rolling problems.
The electrocatalytic reduction of carbon monoxide (CO) has been driving substantial research efforts in developing new catalysts and structures, among which the bimetallic component catalysts feature both functional diversity and...
The electrochemical CO2 reduction to CH4 is a promising approach for producing highly specific combustion fuel but has relatively poor selectivity and activity at high‐current‐density electrolysis. In this work, ultrathin CuGaO2 nanosheets with highly exposed single‐interlayered Cu edges are synthesized via an induced anisotropic growth strategy. Density functional theory calculations indicate that the exposed single‐interlayered Cu(I) edges on the (001) surface of CuGaO2 present a high‐density of single‐atomic Cu sites, which feature excellent CO2 electroreduction catalytic activity toward CH4. The CuGaO2 nanosheet catalysts exhibit efficient and stable CO2‐to‐CH4 electroreduction with Faradaic efficiency (FECH4) of 71.7% at a high current density of –1 A cm−2, corresponding to a superior CH4 partial current density of 717 ± 33 mA cm−2. This work suggests an attractive design strategy for tuning both the crystal facets and Cu–Cu distance to promote the CH4 electrosynthesis at high‐current‐density CO2 reduction.
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