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An efficient thermal emitter for selective radiative cooling is realized with vanadium dioxide metamaterials. The novel structure consists of patterned VO_2 metamaterials on the multilayer substrate and a composite layer on it. To obtain the enhanced emissivity, the influence of the top composite layer and external thermal stimuli are comprehensively optimized. The emissivity can reach up to 0.952 in the metallic phase of VO_2 with a composite layer in the atmospheric window, which is due to strong localization of the electric field in the cavity. The influence on the emissivity with different incident angles and geometric parameters is investigated elaborately. Finally, the cooling power is calculated and achieves a high value of 710W/m^2 at 383 K, which is significantly higher than that of previous works. Thus, our proposed tunable emitter with high performance will be beneficial to the dynamic radiative cooling system and may open a potential application in building cooling and intelligent windows.

Water-soluble β-d-glucan was obtained from wild Cordyceps sinensisby alkali solution and ethanol precipitation. The structure characteristics were determined using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC–PAD), methylation combined with gas chromatography–mass spectrometry, and one-/two-dimensional nuclear magnetic resonance spectroscopy. Results showed that β-d-glucan had a structure of every seven (1→3)-β-d-Glcpbackbone residues with two (1→6)-β-d-Glcpbranches. Additionally, conformation properties in different solvents were investigated by static light scattering, dynamic light scattering, and HPSEC with multiple detectors. It was found that β-d-glucan in 0.5 M NaOH had a narrow unimodal distribution of hydrodynamic radius displaying a spherical coil conformation, whereas it formed severe aggregation in dimethyl sulfoxide. In 0.1 M NaNO3, β-d-glucan mainly existed as a rod-like conformation corresponding to a helical structure together with small aggregates (10%). This work added more information to the understanding of C. sinensispolysaccharides.

The coupled plasmonic film-nanoparticles systems can realize the optical absorption and large electric field enhancement when modes hybridize. In this paper, we report, for the first time, a coupling effect between dark plasmon mode and surface plasmon polaritions in nanorod dimers plasmonic metamaterial. Near-perfect absorption and extremely large field enhancement can be achieved in coupled systems, which provide a new insight to design the high-performance surface enhanced chips for detecting individual molecules.

We present diffractive optical elements with an extended depth of focus, namely, fractal spiral zone plates (FSZPs), which combine a fractal structure and spiral zone plates (SZPs) to generate a sequence of coaxial vortices in the focal volume along the propagation direction. The axial irradiance of the FSZPs is examined both experimentally and in a simulation and is compared with that of SZPs and that of fractal zone plates. The focusing properties of the FSZPs with different parameters are investigated, and a potential application to edge-enhancement images is also shown.

Acrylamide (ACR) generated in carbohydrate-rich foods during thermal processing has been demonstrated to exhibit hepatotoxicity. As one of the most consumed flavonoids with diet, quercetin (QCT) possesses the ability to protect against ACR-induced toxicity, albeit its mechanism is unclear. Herein, we discovered that QCT alleviated ACR-induced elevated levels of reactive oxygen species (ROS), AST, and ALT in mice. RNA-seq analysis revealed that QCT reversed the ferroptosis signaling pathway upregulated by ACR. Subsequently, experiments indicated that QCT inhibited ACR-induced ferroptosis through the reduction of oxidative stress. With autophagy inhibitor chloroquine, we further confirmed that QCT suppressed ACR-induced ferroptosis by inhibiting oxidative stress-driven autophagy. Additionally, QCT specifically reacted with autophagic cargo receptor NCOA4, blocked the degradation of iron storage protein FTH1, and eventually downregulated the intracellular iron levels and the consequent ferroptosis. Collectively, our results presented a unique approach to alleviate ACR-induced liver injury by targeting ferroptosis with QCT.

China's formal long-term care (LTC) system is in its developmental stage due to lack of standardized health assessments for resident admission, limited government funding, an acute shortage of qualified staff at all levels, and regional disparities in quality of care. Relocation to LTC facilities changes the lives of older adults because they have to leave behind their homes and previous social networks. The current study aimed to provide an in-depth exploration of 25 older adult residents' lives in four LTC facilities in China. A conventional content analysis approach was used to interpret participant interviews. Residents experienced losses and gains from residential life. Three themes emerged: (a) China's formal long-term care (LTC) system is in its developmental stage due to lack of standardized health assessments for resident admission, limited government funding, an acute shortage of qualified staff at all levels, and regional disparities in quality of care. Relocation to LTC facilities changes the lives of older adults because they have to leave behind their homes and previous social networks. The current study aimed to provide an in-depth exploration of 25 older adult residents' lives in four LTC facilities in China. A conventional content analysis approach was used to interpret participant interviews. Residents experienced losses and gains from residential life. Three themes emerged: (a) influences of cultural beliefs, (b) basic care needs fulfilled in LTC facilities, and (c) lack of quality care in LTC facilities. Findings show that residents' basic needs were met in Chinese LTC facilities, but there is room for improvement in delivering quality care. [Journal of Gerontological Nursing, 42(8), 34–43.]

We demonstrate theoretically an analogue of electromagnetically induced transparency (EIT) at visible frequencies in an all-dielectric metamaterial-waveguide (ADMW) system that consists of a two-dimensional silicon nanopillar array on top of a dielectric slab waveguide. By varying the lattice period of the array, we show that the transmission feature of the hybridized ADMW system can be efficiently engineered due to the period-dependent guided modes. For ADMW systems with different lattice periods, the EIT-like transparency windows are confirmed either from the two detuned guided modes in the waveguide layer or from the Fano-type interference between the guided modes and the magnetic dipole mode in silicon nanopillars. We have also demonstrated the significant electric field enhancement in the waveguide layer and the remarkable slow-light effect associated with the EIT-like transmission. Compared with the hybrid waveguide-plasmon system including a metal-resonator array, the silicon-based ADMW system enables production of high Q-factor resonances with low absorption losses, thereby having promising applications in low-loss slow-light devices, bio/chemical sensing, enhancing emission rate, and optical modulation.

Abstract

We constructed a four-layer system composed of a prism, a silver film, an air layer and a lithium niobate crystal. Initially we used two coherent light beams to excite surface plasmons. The surface plasmons were then decoupled into light in the photorefractive crystal where a holographic grating was recorded. The two beams remained coherent through light to surface plasmons to light transformation. Studying the characteristics of the holographic grating we found out that the thickness of the grating was to the order of hundreds of microns. The thick holographic grating suggests that the holographic recording in the photorefractive materials was induced by the leaky waves rather than by surface plasmon polaritons directly.

The integrated model of frailty shifted the physiologically-dominated view to an integrated and multidisciplinary view of frailty and adopted an integrated and holistic approach to the complex challenges facing frail older adults and their caregivers. There is an urgent need for researchers to identify multi-faceted frailty among older adults and to explore contributors to it. We assessed the level of frailty among older residents in long-term care (LTC) facilities in Shanghai, China and explored risk factors of multiple dimensions of frailty among older residents.

Solar energy as an inexhaustible source of clean energy has attracted more and more attention. As an important way to collect source of energy, solar absorber is widely reported and studied. However, how to efficiently absorb the solar energy in the solar radiation range is a long-term perplexing problem. In this work, we propose a new type of broadband solar energy absorber based on monolayer molybdenum disulfide (MoS2). Tungsten (W) elliptical arrays are introduced into the structure to enhance its absorption. By exciting local surface plasmon resonance (LSPR) between monolayer MoS2and tungsten elliptical arrays, ultra-broadband solar energy absorber with high absorption rate is obtained. Theoretical calculation by a finite-difference time-domain method (FDTD) shows that absorption with a bandwidth of 1750 nm from about 280 nm to 2030 nm has been achieved. The peak values of resonance wavelength at 1275 nm and 1885 nm are both greater than 99%. Our absorber also has good polarization independence and incidence insensitivity, which provides a theoretical basis for its work in the actual solar environment and possibilities for its application in other solar devices. The inspiration for proposed absorber can also be applied to other transition-metal dichalcogenides (TMDCs).

We present the second-order surface optical nonlinear response of a plasmonic tip under axial excitation of ultrafast vector beams. Theoretical calculations show that the tip has an optimized nanofocusing characteristic under axial excitation of the radial vector beam (RVB), and the electric-field intensity enhancement factor is higher than that of linear polarization beam (LPB) and azimuthal vector beam (AVB) excitations. In the experiment, the second harmonic spectra are clearly measured under three excitation beams. The intensity of the second harmonic obtained via RVB excitation is one order of magnitude higher than that of LPB and AVB excitations.