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A tunable selective emitter with hollow zigzag SiO2 metamaterials, which are deposited on Si3N4 and Ag film, is proposed and numerically investigated for achieving excellent radiative cooling effects. The average emissivity reaches a high value of 98.7% in the atmospheric window and possesses a high reflectivity of 92.0% in the solar spectrum. To reveal the enhanced absorptivity, the confined electric field distribution is investigated, and it can be well explained by moth eye effects. Moreover, tunable emissivity can also be initiated with different incident angles and it stays above 83% when the incident angle is less than 80°, embodying the excellent cooling performance in the atmospheric transparency window. Its net cooling power achieves 100.6 W⋅m−2, with a temperature drop of 13°, and the cooling behavior can persist in the presence of non-radiative heat exchange conditions. Therefore, high and tunable selective emitters based on our designed structure could provide a new route to realizing high-performance radiative cooling. This work is also of great significance for saving energy and environmental protection. [ABSTRACT FROM AUTHOR]

Plasmonic nanostructures have important applications for surface-enhanced Raman chips, optical sensors, perfect absorbers, and so on. In this paper, we theoretically investigate the optical properties of a T-shaped dimer (TD) nanostructure and a TD with nanowire loads (TD/NL) nanostructure. By depositing the NLs around the TD, the optical property of the TD is significantly modified, and the extinction spectrum of composite TD/NL appears the splitting resonance peak and shows the asymmetric characteristic of Fano resonance due to the plasmon hybridization. Besides, a stronger electric field enhancement can be obtained in the composite TD/NL nanostructure, and the calculated results show the field enhancement effect of the dark mode in designed TD/NL nanostructure is three times than that in the TD nanostructure. Furthermore, the Fano resonance in TD/NL nanostructure reveals the narrow spectral linewidth and high quality factor, which is advantageous to optical refractive index sensors, and the corresponding sensing sensitivity is as high as 1083 nm RIU−1. [ABSTRACT FROM AUTHOR]

This cross‐sectional study aimed to determine the prevalence of the co‐occurrence of physical frailty and cognitive impairment and to identify its associated demographic, psychosocial and behavioural factors. Participants were recruited from 32 neighbourhoods using multistage sampling method in Xuhui District, Shanghai, China. A total of 1585 older adults were included who lived in community, were 75 years or older and without a clinical diagnosis of dementia. Based on the presences of frailty (using the modified frailty phenotype criteria) and/or cognitive impairment (using Chinese version Mini‐Mental Status Examination stratified by educational level), the participants were classified into four groups: normal, cognitive impairment alone, frailty alone and co‐occurrence. Multinomial logistic regression analyses were conducted to identify the demographic, psychosocial (depression, social participation and social support) and behavioural (sedentary lifestyle and sleep problems) characteristics associated with the co‐occurrence of physical frailty and cognitive impairment. The prevalence of frailty alone, cognitive impairment alone and the co‐occurrence of physical frailty and cognitive impairment in the study sample were 7%, 26.94% and 7.19% respectively. The results of multinomial logistic regression show the following characteristics significantly associated with the co‐occurrence of physical frailty and cognitive impairment: advanced age (81–85 years old, Odds Ratio, OR = 1.99, 95% CI = 1.10–3.59; 86 years or older, OR = 6.43, 95% CI = 3.66–11.29), number of co‐morbidities (OR = 1.34, 95% CI = 1.01–1.77), depression (OR = 3.88, 95% CI = 2.39–6.29), social participation (OR = 0.61, 95% CI = 0.39–0.96), sedentary lifestyle (OR = 2.69, 95% CI = 1.66–4.34) and sleep problems (insomnia occasionally, OR = 1.84, 95% CI = 1.07–3.17; insomnia every day, OR = 2.38, 95% CI = 1.33–4.26). The co‐occurrence of physical frailty and cognitive impairment is a prevalent health issue in oldest old community‐dwelling older adults. Advanced age, co‐morbidity, depression, sedentary lifestyle and sleep problems are risk factors for cognitive frailty while good social participation may have a protective effect on it. [ABSTRACT FROM AUTHOR]

A water-soluble polysaccharide, named NCSP-50, was obtained from natural Cordyceps sinensis by hot water extraction and ethanol fractionation precipitation. It was eluted as a single symmetrical peak and had an average molecular weight of 9.76 × 10 5 Da. The structure was determined by monosaccharide composition, methylation analysis, 1D/2D NMR spectroscopy, and enzymatic hydrolysis and characterization of the oligosaccharides by MALDI-TOF mass spectrometry. The repeating unit of this polysaccharide was proposed as follows: Image 2 This glucan showed potent immunostimulatory activity on the basis of its significant abilities to promote macrophage proliferation, enhance NO production, as well as and cytokines (IL-1β and TNF-α) secretion. [ABSTRACT FROM AUTHOR]

• A metasurface consisting of disk-ring Si nanostructures on a SiO2 substrate is proposed and numerically simulated. • The Si disk-ring structure can excite and manipulate anapole state. • A transmission dip with a bandwidth of 0.34 nm and a Q-factor of 4460 is shown with maximum E-field enhancement of 346 times. • When the central disk is eccentric, the maximum E-field enhancement can be up to 468 times. • A sensing performance of 387 nm/RIU is shown. In this work, a metasurface consisting of disk-ring Si nanostructures on a SiO 2 substrate is proposed and numerically simulated. The Si disk-ring structure can excite and manipulate anapole state, and periodic array supports lattice resonance simultaneously, which can improve the near-field enhancement in the gap region. The maximum E-field enhancement can be up to 346 times, and a transmission dip with an ultra-narrow bandwidth of 0.34 nm and a Q -factor of 4460 is shown. When the central disk has an offset, the near-field enhancement can be affected. In the case of y -direction offset, the maximum E-field enhancement can be up to 468 times. The near field energy is concentrated in the gap region, easy to interact with probing molecule in surrounding environment. Meanwhile, the designed metasurface shows a sensing performance of 387 nm/RIU. The strong energy confinement and high Q -factor of the proposed structure give an opportunity to enhance the interaction between light and matter, which may have potential applications in nonlinear optics, optical sensors and surface enhanced Raman scattering. [ABSTRACT FROM AUTHOR]

We numerically investigated the optical properties of planar nanorod antennas metamaterial that exhibits plasmon-induced transparency (PIT) effect. The designed metamaterial is made of a silver nanorod dimer antenna surrounded by two parallel silver nanorods. The interaction between two parallel nanorods and middle nanorod dimer antenna leads to a single PIT band in the transmission spectrum. Moreover, the double PIT windows and slow light can be realized by breaking the structure symmetry. The multi-bands PIT effect offers an excellent potential to manipulate the light speed at multi-frequencies. [ABSTRACT FROM AUTHOR]