Synthesizing novel photocatalysts that can effectively harvest photon energy over a wide range of the solar spectrum for practical applications is vital. Porphyrin-derived nanostructures with properties similar to those of chlorophyll have emerged as promising candidates to meet this requirement. In this study, tetrakis(4-carboxyphenyl) porphyrin (TCPP) nanofibers were formed on the surface of ZnO nanoparticles using a simple self-assembly approach. The obtained ZnO/TCPP nanofiber composites were characterized via scanning electron microscopy, X-ray diffraction analysis, and ultraviolet–visible absorbance and reflectance measurements. The results demonstrated that the ZnO nanoparticles with an average size of approximately 37 nm were well integrated in the TCPP nanofiber matrix. The resultant composite showed photocatalytic activity of ZnO and TCPP nanofibers concomitantly, with band gap energies of 3.12 and 2.43 eV, respectively. The ZnO/TCPP photocatalyst exhibited remarkable photocatalytic performance for RhB degradation with a removal percentage of 97% after 180 min of irradiation under simulated sunlight because of the synergetic activity of ZnO and TCPP nanofibers. The dominant active species participating in the photocatalytic reaction were ^•O₂^– and OH^•, resulting in enhanced charge separation by exciton-coupled charge-transfer processes between the hybrid materials.

We studied both experimentally and theoretically the influence of the distance between adjacent cut-wire-pair layers on the magnetic and the electric resonances in the microwave-frequency regime. Besides the dependence on the separation between cut-wire pairs, along the electric-field direction, the electric resonance strongly depends on the distance between cut-wire-pair layers, while the magnetic resonance is almost unchanged. This contrast can be understood by the difference in the distribution of induced-charge density and in the direction of the induced current between the electric and magnetic resonances. A simple model is proposed to simulate our experimental results and the simulation results are in good agreement with the experiment. This result provides important information in obtaining left-handed behavior when the cut-wire pairs are combined with the continuous wire.

We experimentally and numerically studied the transmission spectra of a combined metamaterial structure whose negative refractive index was supposed to be achievable only with simultaneously negative permittivity and permeability. However, it was found that the negativity of the refractive index of such a structure could be obtained not only when both parameters were negative but also when only one parameter, more specifically the permittivity was negative. These characteristics of combined structure were analyzed in detail by using the standard retrieval effective-medium method. According to the analyses, it can be concluded that the negativity originates from the complex permittivity and permeability. The interplay among the real and the imaginary parts of those parameters is the key to the negative behavior of refractive index.

The catalytic triad Cys145–His41–Asp187 of SARS-CoV-2 M^pro plays an important role in the activation of the PF-07321332 covalent inhibitor.