Ever-increasing capacity requirements of optical interconnects drive the emergence and fast development of mode-division-multiplexing (MDM) transmission on-chip, where efficient mode control and conversion components become indispensable. Here, we propose an on-chip silicon
TM
0
-
to
-
TM
1
mode-order converter by leveraging shallowly etched rectangular slots on the top surface of silicon nanowire. The mode conversion region consists of two rectangular slots on the same side of a silicon nanowire and a smaller one between them to realize the efficient mode-order conversion from input
TM
0
to output
TM
1
mode with the help of multimode interference and accumulated phase difference. By studying the etching pattern on the silicon nanowire in detail, we have achieved an on-chip
TM
0
-
to
-
TM
1
mode-order converter with a high conversion efficiency of 97.5% and low modal crosstalk
<2023
The bacterium Aeromonas veronii is a co-pathogenic species that can negatively impact the health of both humans and aquatic animals. In this study, we used single-cell transcriptome analysis (scRNA-seq) to investigate the effects of infection with A. veronii on head kidney cells and the regulation of gene expression in the dark sleeper (Odontobutis potamophila). scRNA-seq was used to assess the effects of infection with A. veronii in O. potamophila B cells, endothelial cells, macrophages, and granulocytes, and differential enrichment analysis of gene expression in B cells and granulocytes was performed. The analyses revealed a significant increase in neutrophils and decrease in eosinophils in granulocytes infected with A. veronii. Activation of neutrophils enhanced ribosome biogenesis by up-regulating the expression of RPS12 and RPL12 to fight against invading pathogens. Crucial pro-inflammatory mediators IL1B, IGHV1-4, and the major histocompatibility class II genes MHC2A and MHC2DAB, which are involved in virulence processes, were upregulated, suggesting that A. veronii activates an immune response that presents antigens and activates immunoglobulin receptors in B cells. These cellular immune responses triggered by infection with A. veronii enriched the available scRNA-seq data for teleosts, and these results are important for understanding the evolution of cellular immune defense and functional differentiation of head kidney cells.
Mode-order converters drive the on-chip applications of multimode silicon photonics. Here, we propose a TM0-to-TM3 mode-order converter by leveraging a shallowly etched slot metasurface pattern atop the silicon waveguide, rather than as some previously reported TE-polarized ones. With a shallowly etched pattern on the silicon waveguide, the whole waveguide refractive index distribution and the corresponding field evolution will be changed. Through further analyses, we have found the required slot metasurface pattern for generating the TM3 mode with high conversion efficiency of 92.9% and low modal crosstalk <−19 dB in a length of 17.73 μm. Moreover, the device’s working bandwidth and the fabrication tolerance of the key structural parameters are analyzed in detail. With these features, such devices would be beneficial for the on-chip multimode applications such as mode-division multiplexing transmission.
Mode-order converter is a pivotal component in the on-chip multimode optical transmissions with different mode orders. In this work, we propose a compact and highly-efficient TM 0 -to-TM 2 modeorder converter using shallowly-etched rectangular slots on the silicon-on-insulator platform. The proposed device consists of four same shallowly-etched slots in symmetrical arrangements (two by two) along the light propagation direction and a smaller one between them, which can change the refractive index distribution of the silicon waveguide and add accumulated phase difference through light propagation. With detailed optimizations, we realize the efficient mode conversion from input TM 0 mode to output TM 2 mode, which is different from some reported TE-polarized mode-order converters, and the insertion loss and conversion efficiency of the present device are 0.21 dB and 94.3%, respectively, in a total device length of only 8.97 μm. Meanwhile, the modal crosstalk is lower than −15 dB and the bandwidth can be extended to ∼100 nm. We believe this device could be applied in the on-chip multimode optical transmission systems with different mode orders to further improve the link capacity.
Berberine hydrochloride is an isoquinoline alkaloid, which has antitumoral, antibacterial, and antiviral activities in vivo and in vitro. Charybdis japonica is one of the main economic species of crab in Southeast Asia. We studied the molecular mechanism of oxidative stress in berberine hydrochloride-treated C. japonica infected with Aeromonas hydrophila. C. japonica were infected with A. hydrophila after being submerged in different concentrations (0, 100, 200, and 300 mg/L) of berberine hydrochloride for 48 h. The full-length cDNA of Prx6 and the ORFs of Prx5 and PXL2A were cloned. Prx6 and PXL2A each have one conserved domain, Cys44, and Cys81. The Prx5 conserved domain contains three important Cys loci, Cys75, Cys100, and Cys76. Prx6 was different from Prx5 and PXL2A in the Peroxiredoxin family. The transcription levels of PXL2A infected with A. hydrophila were all higher than the control. The transcription levels of C. japonica were further increased by adding berberine hydrochloride and were increased the highest at a concentration of 300 mg/L. The activities of glutathione peroxidase, superoxide dismutase, and catalase in the hepatopancreas of berberine hydrochloride-treated C. japonica infected with A. hydrophila were significantly increased compared with those only infected with A. hydrophila and the control group. The glutathione transferase activity in the hepatopancreas was significantly increased in berberine hydrochloride-treated C. japonica. The results of this study provide a new understanding of the potential role of berberine hydrochloride on the oxidative stress mechanisms of C. japonica.
A design method for a dynamically tunable multifunctional device, which is insensitive to polarization while maintaining unbroken reciprocity, is proposed. The device utilizes a multilayer composite symmetrical structure incorporating vanadium dioxide (VO2). This design enables dynamic switching among the functions of linear polarization conversion, filtering, and absorption. In the polarization conversion state, the device achieves orthogonal deflection of incident waves at any polarization angle, with a polarization conversion ratio (PCR) exceeding 95%. When switched to the filtering function, a band-stop filter with a −20 dB bandwidth of 0.56 THz is obtained. In the absorption function, the device exhibits a peak absorption efficiency of up to 99%. Furthermore, the paper discusses the potential for a dual-band device based on the proposed structure. The device maintains reciprocity in all functions and effectively handles incident waves from both positive and negative directions. This adaptability and flexibility make it suitable for various applications, including switches, sensors, and modulators.
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