We propose and numerically investigate a multi-parameter integrated sensor based on a selectively filled D-shaped photonic crystal fiber (PCF). The simple structure can be used to comprehensively ...detect refractive index, magnetic field, temperature, and voltage. According to the surface plasmon resonance and directional coupling effect, the PCF is coated with a gold nano-film to detect the refractive index of the external environment. In addition, magnetic fluid (water-based Fe
O
), toluene, and nematic liquid crystal (NLC E7) are selectively filled into different cladding air holes of the D-shaped PCF to realize the different sensing of the magnetic field, temperature, and voltage. The measurement of refractive index, magnetic field, temperature, and voltage are independent of each other, so these four parameters can be measured simultaneously. The sensing characteristics of the proposed structure are investigated systematically by the finite element method. The results show that the sensitivities of refractive index, magnetic field, temperature, and voltage are 4600 nm/RIU, 1.375 nm/Oe, 15.143 nm/°C, and 0.971 nm/V, respectively. The presented design based on materials selectively filled with D-shaped PCF might enable promising application in multi-parameter optical sensing.
All-dielectric Huygens’ metasurfaces have been widely used in wavefront manipulation through multipole interactions. Huygens’ metasurfaces utilize the superposition between an electric dipole and a ...magnetic dipole resonance to realize transmission enhancement and an accumulated 2π phase change. Benefiting from this unique property, we design and numerically investigate an all-dielectric Huygens’ metasurface exhibiting high-efficiency anomalous refraction. To suppress the substrate effect, the metasurface structure is submerged in a dielectric plate. We strategically placed two elements in four short periods to form a unit cell and adjusted the spacing between the two elements to effectively inhibit the interaction between elements. At the operating wavelength of 692 nm, the obtained anomalous transmission efficiency is over 90.7% with a diffraction angle of 30.84°. The performance of the proposed structure is far superior to most of the existing phase-gradient metasurface structures in the visible region, which paves the way for designing efficient beam deflection devices.
Background. Protein energy malnutrition (PEM), a common cause of secondary immune deficiency in children, is associated with an increased risk of infections. Very few studies have addressed the ...relevance of PEM as a risk factor for influenza. Methods. We investigated the influence of PEM on susceptibility to, and immune responses following, influenza virus infection using isocaloric diets providing either adequate protein (AP; 18%) or very low protein (VLP; 2%) in a mouse model. Results. We found that mice maintained on the VLP diet, when compared to mice fed with the AP diet, exhibited more severe disease following influenza infection based on virus persistence, trafficking of inflammatory cell types to the lung tissue, and virus-induced mortality. Furthermore, groups of mice maintained on the VLP diet showed significantly lower virus-specific antibody response and a reduction in influenza nuclear protein-specific CD8⁺ T cells compared with mice fed on the AP diet. Importantly, switching diets for the group maintained on the VLP diet to the AP diet improved virus clearance, as well as protective immunity to viral challenge. Conclusions. Our results highlight the impact of protein energy on immunity to influenza infection and suggest that balanced protein energy replenishment may be one strategy to boost immunity against influenza viral infections.
In recent years, many intriguing electromagnetic (EM) phenomena have come into being utilizing metasurfaces (MSs). However, most of them operate in either transmission or reflection mode, leaving the ...other half of the EM space completely unmodulated. Here, a kind of transmission-reflection-integrated multifunctional passive MS is proposed for entire-space electromagnetic wave manipulation, which can transmit the x-polarized EM wave and reflect the y-polarized EM wave from the upper and lower space, respectively. By introducing an H-shaped chiral grating-like micro-structure and open square patches into the unit, the MS acts not only as an efficient converter of linear-to-left-hand circular (LP-to-LHCP), linear-to-orthogonal (LP-to-XP), and linear-to-right-hand circular (LP-to-RHCP) polarization within the frequency bands of 3.05-3.25, 3.45-3.8, and 6.45-6.85 GHz, respectively, under the x-polarized EM wave, but also as an artificial magnetic conductor (AMC) within the frequency band of 12.6-13.5 GHz under the y-polarized EM wave. Additionally, the LP-to-XP polarization conversion ratio (PCR) is up to -0.52 dB at 3.8 GHz. To discuss the multiple functions of the elements to manipulate EM waves, the MS operating in transmission and reflection modes is designed and simulated. Furthermore, the proposed multifunctional passive MS is fabricated and experimentally measured. Both measured and simulated results confirm the prominent properties of the proposed MS, which validates the design's viability. This design offers an efficient way to achieve multifunctional meta-devices, which may have latent applications in modern integrated systems.
In this study we demonstrate a high-performance polarization rotator (PR) based on flat-shaped photonic crystal fiber. The flat surfaces of the fiber are plated on gold films as electrodes, and the ...core of the structure is filled with liquid crystal. The polarization rotation characteristics of the flat-shaped fiber can be effectively adjusted by applying external voltage. The optical properties are analyzed using the finite element method (FEM). The results show that the magnitude of the modulation voltage is closely related to the thickness of the flat fiber. When the fiber thickness is 20 μm, only 100 V is required to achieve the highest PR performance. In the wavelength of the 1.55 μm band (~200 nm bandwidth), the conversion length of the PR is only 3.99 μm, the conversion efficiency is close to 100%, and the minimum crosstalk value is −26.2 dB. The presented PR, with its excellent performance, might enable promising applications in the communication system and the photonic integrated circuits.
Compared to traditional soil improvement methods such as preloading, vertical drains, or grouting injection, et al., pile-supported reinforced embankments are increasing widely employed in the ...construction of highways on soft soils. A series of three-dimensional model tests on pile-reinforced embankments, utilizing a square arrangement for pile caps, were conducted to investigate the effects of pile-subsoil relative displacement, embankment height, tensile strength of geotextiles, and clear spacing of pile caps on the stress concentration ratio and the height of the equal settlement plane. The results indicate a close relationship between the soil arching effect and pile-subsoil relative displacement. The stress concentration ratio, from the results of this study, reaches its maximum value when the pile-subsoil relative displacement is approximately 6–8 mm. A larger embankment height to pile-cap clear spacing ratio, h/s, as well as the of pile-cap width to its clear spacing ratio, b/s, will result in a larger stress concentration ratio and a smaller differential settlement on the embankment surface. The inclusion of geotextiles can effectively enhance the soil arching effect, i.e., increasing the stress concentration ratio and lessening the fill differential settlement, especially for those low embankments. The model test results also shown that the height of the equal settlement plane in 3D soil arch is approximately 3.5 times the pile-cap clear spacing regardless of the inclusion of the geotextiles or not. In addition, by comparing the measured stress concentration ratio with the calculated values from various design methods, valuable conclusions have been derived.
In this paper, we proposed a multibeam switching antenna based on a low-cost reconfigurable hybrid metasurface applied for beamforming systems. The antenna consists of two parts: a microstrip feed ...antenna and a transmission hybrid metasurface. The latter is composed of three types of units with different amplitude and phase responses to electromagnetic waves so as to control the beams of the feed antenna. Sixteen PIN diodes are arranged in the metasurface with a simple bias network. When two different direct-current voltages are applied to the PIN diodes, the antenna can dynamically switch between two beams and four beams. For demonstration, the proposed antenna is fabricated, and the measured results show that the antenna operates at 9.07–9.42 GHz (−10 dB bandwidth) with a total size of 1.80λ0 × 1.52λ0 × 0.22λ0 (λ0 corresponds to the wavelength of 9.28 GHz in free space). With the merits of a compact structure, low cost and good radiation performance, the proposed design is suitable for beamforming applications.
Bacterial contamination has caused a major public health problem worldwide. Bacillus cereus is a conditional environmental pathogenic bacteria that can cause food poisoning. Whether environmental ...pathogens can cause widespread transmission in the insect kingdom is unclear. In this study, a Bacillus cereus ZJ-4 was isolated from the hospital environment of Zhenjiang City, Jiangsu Province, China. It was fatal by injection into the silkworm hemolymph. To investigated the potential toxic factors of ZJ-4 and clarified the toxicity response mechanism of silkworm by the ZJ-4 infection. Then, the whole genome of ZJ-4 was sequenced, and the immune mechanism of silkworm fat body to ZJ-4 pathogen was studied by HE pathological section and proteomics. Bacterial genome sequencing indicated that ZJ-4 had 352 drug resistance genes and 6 virulence genes. After 36 h of subcutaneous puncture with ZJ-4 suspension, the pathological changes were obviously found in HE pathological sections of fat body tissue. Comparative proteomic results indicated that differentially expressed proteins are mainly involved in stress reactions, biological regulation, and innate immunity. The qRT-PCR analysis showed that the expressions of β-GRP, Spaetzle, MyD88, Tube and Dorsal genes in Toll pathway were up-regulated, while Pell and Cactus genes were down-regulated; in the antimicrobial peptide pathway, Glv2, Lzm, Mor, and Leb3 genes were up-regulated, while attacin1 and defensin genes were down-regulated; Sod gene was up-regulated, while Cat gene was down-regulated in the antioxidant pathway; Ldh, Sdh, and Mdh genes were down-regulated in glucose metabolism pathway. These results indicated that ZJ-4 can damage the innate immune pathway of silkworm, and also affect the normal immune function of fat body cells.
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•A new B. cereus strain named Bacillus cereus ZJ-4 was isolated from hospital environmental.•The whole genome information of B. cereus ZJ-4 was sequenced.•The virulence genes of B. cereus ZJ-4 were difference from other Bacillus cereus.•B. cereus ZJ-4 could damage the innate immune response of silkworm fat body.
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