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This study investigates the curved worldline of a charged particle accelerated by an electromagnetic field in flat spacetime. A new metric, which dependes on the charge-to-mass ratio and electromagnetic potential, is proposed to describe the curve characteristic of the world-line. The main result of this paper is that an equivalent equation of the Lorentz equation of motion is put forward based on a 4-dimensional Riemannian manifold defined by the metric. Using the Ricci rotation coefficients, the equivalent equation is self-consistently constructed. Additionally, the Lorentz equation of motion in the non-inertial reference frames is studied with the local Lorentz covariance of the equivalent equation. The model attempts to geometrize classical electromagnetism in the absence of the other interactions, and it is conducive to the establishment of the unified theory between electromagnetism and gravitation.

The location of Îł -ray-emitting region in blazars has been an open issue for several decades and is still being debated. We use the Paliya et al. sample of 619 Îł -ray-loud flat-spectrum radio quasars with available spectral energy distributions and employ a seed photon factor approach to locate the Îł -ray production region. This method efficiently sets up a relation between the peak frequencies and luminosities for the synchrotron emission and inverse Compton scattering, together with a combination of the energy density and characteristic energy for the external seed photon field, namely, U 0 / ϵ 0 , an indicative factor of seed photons in units of Gauss. By comparing it with canonical values of the broad-line region (BLR) and molecular dusty torus (DT), we principally ascertain that the GeV emission originated far beyond the BLR and close to the DTâ€"farther out at parsec scales from the central black hole, which supports a far-site scenario for Îł -ray blazars. We probe the idea that inverse Compton scattering of infrared seed photons is happening in the Thomson regime. This approach and our findings are based on the validity of the external Compton model, which is applicable in understanding the GeV emission mechanism in FSRQs. However, the completeness of this framework has been challenged by reports of neutrino emission from blazars. Thus, we also shed new light on the neutrino production region by using our derived results because blazars are promising neutrino emitters. [ABSTRACT FROM AUTHOR]

Energy-free radiative cooling is a green and ideal solution to replace air conditioning by reflecting sunlight spontaneously and radiating excess heat through atmospheric transparency windows to outer space for passive cooling. However, most radiative cooling materials are susceptible to contamination by dust, rain, etc., which reduces the cooling capacity in outdoor environments. Herein, we report on a superhydrophobic daytime radiative cooling coating based on SiO 2- coated glass bubble (SiO 2 -GB) powder that achieves strong sunlight reflectivity (96%) and high mid-infrared emissivity (98%), effectively producing an ambient temperature drop of 11.1 °C in direct outdoor sunlight. More importantly, the coating has good superhydrophobic properties with a water contact angle of 157°, which allows the coating to be self-cleaning to keep the coating free from contamination and effectively maintain good radiation cooling performance. In addition, the prepared coatings remain hydrophobic and keep good radiative cooling properties when exposed to different pH solutions and long-term exposure to UV irradiation, which has important implications for sustainable applications, and our work holds great promise for the energy efficiency of building materials and their long-term outdoor service.

Non-small cell lung cancer (NSCLC) is considered to be a principal cause of cancer death across the world, and nanomedicine has provided promising alternatives for the treatment of NSCLC in recent years. Photothermal therapy (PTT) and chemodynamic therapy (CDT) have represented novel therapeutic modalities for cancer treatment with excellent performance. The purpose of this research was to evaluate the effects of PPy@Fe 3 O 4 nanoparticles (NPs) on inhibiting growth and metastasis of NSCLC by combination of PTT and CDT. In this study, we synthesized PPy@Fe 3 O 4 NPs through a very facile electrostatic absorption method. And we detected reactive oxygen species production, cell apoptosis, migration and protein expression in different groups of A549 cells and established xenograft models to evaluate the effects of PPy@Fe 3 O 4 NPs for inhibiting the growth of NSCLC. The results showed that the PPy@Fe 3 O 4 NPs had negligible cytotoxicity and could efficiently inhibit the cell growth and metastasis of NSCLC in vitro . In addition, the PPy@Fe 3 O 4 NPs decreased tumor volume and growth in vivo and endowed their excellent MRI capability of observing the location and size of tumor. To sum up, our study displayed that the PPy@Fe 3 O 4 NPs had significant synergistic effects of PTT and CDT, and had good biocompatibility and safety in vivo and in vitro . The PPy@Fe 3 O 4 NPs may be an effective drug platform for the treatment of NSCLC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Fang, Jin, Huang, Shi, Liu and Ben.)