RESUMO
This work presents a theoretical design and experimental demonstration of a novel miniaturized leaky-wave antenna (LWA) using composite waveguide based on substrate-integrated plasmonic waveguide (SIPW). The SIPW is designed by embedding hybrid dual spoof surface plasmon polariton (SSPP) structure into a three-layer substrate integrated waveguide (SIW). Due to the slow-wave effect of SIPW, the proposed miniaturized composite waveguide forms slowed phase velocity and decreased lower cutoff frequency. To excite backward-to-forward beam scanning mode and suppress the open stop-band, an asymmetric sinusoidal modulated structure is introduced to the surface of the composite waveguide. The experimental results indicate that the proposed SIPW-based LWA can achieve continuous beam scanning from the backward to the forward direction within the bandwidth of 10.6-13.7â GHz, passing through the broadside at 11.6â GHz.
RESUMO
In this paper, a hybrid mechanism metasurface (HMM) employing 1-bit random coding is proposed to achieve polarization-insensitive and dual-wideband monostatic/bistatic radar cross section (RCS) reduction under a wide range of incident angles. The anisotropic unit cell is designed by the combination of the multi-objective particle swarm optimization (MOPSO) algorithm and Python-CST joint simulation, which facilitates the rapid acquisition of the desired unit cell with excellent dual-band absorption conversion capability. The unit cell and its mirrored version are used to represent the units "0" and "1", respectively. In addition, the array distribution with random coding of the units "0" and "1" is optimized under different incident angles, polarizations and frequencies, which enables better diffusion-like scattering. Simulation results demonstrate that the proposed coding HMM can effectively reduce the monostatic/bistatic RCS by over 10 dB within the dual-band frequency ranges of 2.07-3.02 THz and 3.78-4.71 THz. Furthermore, the specular and bistatic RCS reduction performances remain stable at oblique incident angles up to 45° for both TE and TM polarizations.
RESUMO
Ulcerative colitis (UC), a chronic inflammatory bowel disease, substantially impacts patients' health-related quality of life. In this study, an effective strategy for discovering high-efficiency probiotics has been developed. First, in order to survive in the conditions of the stomach and intestine, high bile salt-resistant and strong acid-resistant strains were screened out from the fecal flora of healthy adults. Next, the probiotic candidates were rescreened by examining the induction ability of IL-10 (anti-inflammatory factor) production in dextran sodium sulfate (DSS)-induced colitis mice, and Lactobacillus sakei 07 (L07) was identified and selected as probiotic P. In the end, fourteen bifidobacterium strains isolated from stools of healthy males were examined for their antimicrobial activity. Bifidobacterium bifidum B10 (73.75% inhibition rate) was selected as probiotic B. Moreover, the colonic IL-6 and TNF-α expression of the DSSinduced colitis mice treated with L. sakei 07 (L07) - B. bifidum B10 combination (PB) significantly decreased and the IL-10 expression was up-regulated by PB compared to the DSS group. Furthermore, Bacteroidetes and Actinobacteria decreased and Firmicutes increased in the DSS group mice, significantly. More interestingly, the intestinal flora biodiversity of DSS colitis mice was increased by PB. Of those, the level of B. bifidum increased significantly. The Bacteriodetes/Firmicutes (B/F) ratio increased, and the concentration of homocysteine and LPS in plasma was down-regulated by PB in the DSS-induced colitis mice. Upon administration of PB, the intestinal permeability of the the DSS-induced colitis mice was decreased by approximately 2.01-fold. This method is expected to be used in high-throughput screening of the probiotics against colitis. In addition, the L. sakei 07 - B. bifidum B10 combination holds potential in UC remission by immunomodulatory and gut microbiota modulation.