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The effects of diets fermented with compound probiotics, namely Lactobacillus acidophilus, Limosilactobacillus reuteri and Lactiplantibacillus plantarum, on the growth performance, physiological and biochemical indexes, fatty acid composition and intestinal health of juvenile largemouth bass (Micropterus salmoides) were investigated. Three hundred healthy juvenile M. salmoides (5.29 ± 0.02 g) were selected and randomly divided into two groups with triplicates for each. The basic diet was set as the control group (CON), and fermentation of the basic diet with a mixed bacterial solution (1.8 × 109 cfu/mL, L. acidophilus:L. reuteri:L. plantarum = 1:1:1) was set as the fermentation group (FER). Fish were hand fed to satiation for 56 days and two-thirds of the culture water was renewed every 3 days. The results showed that feed intake of fish in the FER group was significantly lowered, thereby increasing feed efficiency (FE) and protein efficiency (PER) (p < 0.05). Serum alanine aminotransferase (ALT) activity was significantly decreased, and catalase (CAT) activity was significantly increased in the FER group (p < 0.05). The liver superoxide dismutase activity (SOD) was significantly enhanced, and intestinal trypsin was significantly increased in the FER group (p < 0.05). Being fed with the fermentation diet significantly increased the content of n-3 polyunsaturated fatty acids (PUFA), docosahexaenoic acid (DHA) and the n-3/n-6 PUFAs ratios in the liver (p < 0.05). Intestinal histology showed that villus height and width of the intestine and the number of goblet cells were significantly increased in the FER group (p < 0.05). Those fed with fermentation diets had limited diversity of gut microbiota. Compared to the CON group, the relative abundance of Aeromonas decreased significantly (p < 0.05), while the relative abundance of Fusobacteria, Cetobacteria and Lactobacillusis in FER increased greatly in the gut microbiota of the FER group. In conclusion, fermented feed with the three probiotics effectively improved the feed utilization and antioxidant capacity, promoted digestion and absorption of dietary protein, improved the ability of synthesize DHA and n-3 PUFAs in the liver and reduced the abundance of pathogenic bacteria in the gut. Therefore, the present research provided a new way of co-fermented feed with three probiotics for the aquaculture of M. salmoides. [ABSTRACT FROM AUTHOR]

A prior-knowledge-guided deep-learning-enabled (PK-DL) synthesis method is proposed for enhancing the transmission bandwidth and phase shift range of metacells used for the design of metalens antennas. The algorithm of conditional deep convolutional generative adversarial network (cDCGAN) is utilized in the proposed deep-learning (DL) method. Prior knowledge, including well-known fundamental electromagnetic theorems and experience in antenna design, is purposely applied at the early stage of the proposed method to strategically guide and speed up the synthesis. The proposed intelligent method provides the design of pixelated metacells with high degrees of freedom so that the key performance of the synthesized metacells exceeds the existing limit of conventional design methods by generating a rich profusion of cell patterns. For example, the synthesized triple-layer metacell achieves the −1 dB phase shift range of 330° breaking the limit of 308° derived by existing techniques. The proposed synthesis method also provides the additional capability to flexibly control the phase shift not only at the center frequency but also over a frequency range of interest. A Ku-band metalens antenna formed with the synthesized metacells demonstrates the achieved 1 and 3 dB gain bandwidths increase by 52.2% and 42.6%, respectively, compared to the metalens antenna using the well-known Jerusalem cross (JC) metacells. The proposed method extends the capability for the synthesis of metacells and metalens antennas with enhanced performance. [ABSTRACT FROM AUTHOR]

In this article, an omnidirectional dual-polarized antenna with low windage is presented within a wedge-profiled structure for supersonic onboard systems. Based on aerodynamic analysis, a wedge-profiled cavity is designed with colocated slots for omnidirectional and dual-polarized radiation. For horizontal polarization, two identical half-wavelength slots are etched onto the cavity sidewalls symmetrically. The vertical polarization is achieved by another horizontal slot, with the port isolation higher than 42 dB. A low windage coefficient of 0.11 is obtained within the wedge-profiled cavity with the dimensions of $41.6 \times 16 \times 30$ mm3 ($0.34\lambda _{0} \times 0.13\lambda _{0} \times 0.24\lambda _{0}$). The proposed antenna is constructed and tested, with the measured results in agreement with the simulated ones. The operating bandwidths cover the band of 2.40–2.48 GHz, and the gain variations below 3.5 dB are realized in the azimuthal plane for both polarizations. The proposed wedgy antenna is with both electromagnetic and aerodynamic considerations, exhibiting the potentials in supersonic onboard communication systems. [ABSTRACT FROM AUTHOR]

In this communication, a planar antenna array is proposed in millimeter-wave bands by using a modified bulk silicon micromachining technology. The proposed antenna array is designed and fabricated based on air-filled microstrip line structures. By periodically blocking the microstrip line, fringing electric fields along the microstrip lines are excited in phase, which contributes to achieving high gain performance with a relatively compact feeding structure. Moreover, the proposed antenna array is designed and fabricated by a modified bulk silicon micromachining technology. The process is quite suitable for designing low loss antennas in millimeter-wave bands. In the process, the silicon wafers are deeply etched and gold-plated. As a result, microstrip line structures in the proposed antenna array are filled with air medium, which mitigates dielectric loss and improves radiation efficiency. A prototype of the proposed antenna array is fabricated and tested to verify the design strategy. The dimension of the antenna array is $49.40\times 20.00\times0.75$ mm3. The simulated −10 dB bandwidth is 58.8–59.7 GHz and the measured bandwidth is 58.8–59.5 GHz. In the operating band, the maximum simulated gain of the proposed antenna is 19.8 dBi and the minimum simulated gain is 18.3 dBi. The measurement results illustrate that the maximum gain of the proposed antenna array is 18.8 dBi and the minimum gain is 17.0 dBi. [ABSTRACT FROM AUTHOR]

In this article, the guided-wave modes and leaky-wave characteristic of rectangular metal strips are investigated to realize endfire radiation. By strategically exciting the high-order TE1 leaky-wave mode in the metal strip, a transverse in-phase $E$ -field could be realized to generate an endfire radiation. An effective scheme is validated to manipulate the phase constant and leaky rate by altering the width of the TE1 mode metal strip. Then, to further tailor the phase constant and leaky rate for achieving an enhanced directivity, periodic grooves are etched on both edges of the metal strip to slowdown the phase velocity to a surface-wave mode. To verify this concept, an all-metal planar prototype of corrugated rectangular metal strip (CRMS) was fabricated and measured. Both the full-wave simulation and experimental results show that the CRMS could offer a high endfire gain of 14.2 dBi within a footprint of $3.0\times 0.5\lambda _{0}^{2}$. Moreover, a broad overlapping bandwidth of 27.7% is realized with $S_{11} < -10$ dB, gain variation less than 3 dB, and total efficiency better than 90%. The proposed design scheme paves the way for the traveling-wave antenna with simple structure, wide bandwidth, high gain, and good platform accommodation. [ABSTRACT FROM AUTHOR]

In this communication, a circularly polarized (CP) reconfigurable 2 bit antenna array is proposed for beam-steering applications. The proposed antenna array utilizes a novel CP reconfigurable 2 bit patch antenna as radiation element. For a reconfigurable 2 bit element, there should be four phase states (i.e., 0°, 90°, 180°, and 270°). In the proposed radiation element, a corner truncated microstrip patch antenna is presented for CP radiation. Owing to the symmetry of the patch antenna, the 0° and 180° phase states are achieved by selecting feeding points of the patch instead of using complex feeding network. A 90° digital phase shifter is cascaded to realize the 90° and 270° phase states for the 2 bit reconfigurable element. Based on the novel 2 bit CP element, an eight-element CP reconfigurable 2 bit antenna array is fabricated and tested to verify the design strategy at 3.65 GHz. The measured results match well with simulation. By appropriately controlling the ON and OFF states of p-i-n diodes, the proposed CP array can be steered from −49° to +49°. [ABSTRACT FROM AUTHOR]

In this communication, a compact saber-like antenna with low wind drag is proposed for on-board communication application, under the requirements of polarization diversity and omnidirectional coverage. The proposed antenna consists of a thin resonant cavity for omnidirectional horizontal polarization (HP), and a folded slot is colocated with the cavity to provide omnidirectional vertical polarization (VP). Isolation lower than −20 dB between two feeding ports is achieved in a quite compact dimension of $30 \times 29 \times 9$ mm3($0.24\lambda _{0} \times 0.24\lambda _{0} \times 0.07\lambda _{0}$ , $\lambda _{0}$ is the free-space wavelength at 2.44 GHz), also with the omnidirectional patterns for both polarizations. A prototype of the proposed antenna is fabricated and tested to verify the design strategy. Compared with previous designs, the cross section area for wind drag is reduced for more than 28.5%, exhibiting potential usage for high-speed moving antenna carriers. [ABSTRACT FROM AUTHOR]

A low-profile endfire leaky-wave antenna is proposed in this paper. The proposed low profile antenna utilizes microstrip line to excite planar inverted-L antenna (PILA) elements. Air media is utilized in the proposed array to realize the endfire property. By using air media, the proposed leaky-wave array maintains phase constant slightly larger than the wavenumber in free space and achieves endfire radiation. PILA elements are periodically spaced to radiate and the spacing period is designed as \lambda 0 /4 ( \lambda 0 is the wavelength in free space) to achieve a relatively wide impedance bandwidth. A prototype of the proposed endfire antenna is fabricated and tested. The measured results are consistent with full-wave simulation results. The length of the whole leaky-wave array is about 6\lambda 0 , and the measured gain in the endfire direction is 11.5 dBi at 5.1 GHz. [ABSTRACT FROM PUBLISHER]

In this paper, a millimeter-wave air-filled slot antenna is presented based on bulk silicon microelectromechanical systems micromachining technology. The antenna is suitable for system-in-package application by utilizing this silicon micromachining technique. To achieve high radiation efficiency in millimeter-wave band, three gold-plated silicon layers are bonded together to realize an air-filled slot antenna. The air-filled structure has the advantages of reducing transmission loss and enhancing the radiation gain. To mitigate the discontinuity between silicon and air, the proposed antenna employs a patch to feed the air-filled structure that also broadens the impedance bandwidth. Owing to the micromachining technique and the air-filled structure, the antenna can be easily integrated with integrated circuit without suffering from dielectric loss. The measured impedance bandwidth of the proposed antenna is 56.3–63.4 GHz, and the measured peak gain is 7.8 dBi at 60 GHz. [ABSTRACT FROM PUBLISHER]

A fixed-beam leaky-wave slot antenna with an air-filled back cavity is proposed in the millimeter-waveband. The antenna is fabricated based on the bulk silicon microelectromechanical systems micromachining technology. This micromachining process can etch silicon wafers and plate them with gold. Because all surfaces of the proposed antenna are plated with gold, electromagnetic waves can transmit in the air medium without any other dielectric. The air-filled structure contributes to achieving a leaky-wave slot antenna with fixed beam as operating frequency varies. A prototype of the proposed antenna is fabricated to verify the design strategy. The measured results show that the impedance bandwidth of the proposed antenna is 55–67 GHz and within the operating frequency band, the main beam direction only varies from 48° to 53°, which confirms the fixed-beam characteristic. The measured peak gain varies from 9.1 to 10.5 dBi in the operating frequency band. [ABSTRACT FROM AUTHOR]

Microalgae exhibit diverse and high nutritional value, and therefore, have a huge potential application as a raw material for the preparation of aquafeeds. This study was conducted to evaluate the effects of low-level replacement of dietary fishmeals by algal meals comprised of Schizochytrium limacinum (SL) and Nannochloropsis salina (NS) individually and in combination in the diet of juvenile largemouth bass (LMB, Micropterus salmoides). Five isonitrogenous, isolipidic, and isoenergetic diets with fishmeal-based diets as control, and four experimental diets with replacement by individual 4% SL (4SL), individual 4% NS (4NS), 2% SL combined with 2% NS (2SL + 2NS) and 4% SL combined with 4% NS (4SL + 4NS) were formulated. Five hundred juvenile fish (average weight 8.72 ± 0.10 g) were evenly distributed to five groups with quadruplicate each, in twenty fiberglass tanks and fed for eight weeks. Our results showed that there were no significant difference in weight gain, special gain rate, hepatosomatic index, viscerasomatic index, conditioning factor, and the whole-body composition among the five groups (p > 0.05). However, feed intake and feed conversion ratio in the 4NS treatment were significantly higher (p < 0.05) compared with the control. Further, lipid content and intraperitoneal fat ratio in the liver of the 4NS and 4NS + 4SL groups were significantly decreased, suggesting that NS may reduce visceral fat accumulation in LMB. The serum superoxide dismutase (SOD) activity of LMB in the 4NS group was significantly increased compared with the control (p < 0.05). However, malondialdehyde (MDA) content in the liver of the 4NS group and intestine of the 4SL + 4NS group was significantly lower than that in the control (p < 0.05). Replacement with 4% SL significantly increased docosahexaenoic acid, polyunsaturated fatty acids (PUFAs), and n-3 PUFA proportions in the liver. Further, SL alone or in combination with NS increased the n-3 to n-6 ratio of PUFAs in the liver and muscle, creating more balanced unsaturated fatty acids. The fillet texture was significantly enhanced by taste and flavor. Nevertheless, the present study verified the successful addition of SL and NS algal meals to fish feed, which exhibited excellent potential to replace fishmeals and fishoil, respectively, as protein and lipid sources. • Effects of fishmeal replacement by algal meals on largemouth bass were evaluated. • Low-level substitution had no negative effect on growth or whole-body composition. • Fishmeal replacement (4%) with Nannochloropsis salina decreased lipid deposition. • Fishmeal replacement (4%) with Schizochytrium limacinum increased docosahexaenoic acid. [ABSTRACT FROM AUTHOR]

In this paper, a low‐power‐consumption massive multiple‐input and multiple‐output (MIMO) scheme with an integrated multibeam antenna array is proposed for the green fifth‐generation (5G) communication base stations. The referenced antenna array includes 8 × 16 dual‐polarized antennas with Butler matrix networks, leading to low radiofrequency (RF) complexity and low consumption. The measured results demonstrate that the antenna array achieves four beam clusters with a 45° coverage in elevated plane, with gain of 15.4 dBi at 3.6 GHz. Based on this, the generated beam clusters and corresponding RF chains can be switched independently according to the real‐time user scenario. It is analyzed that the consumption for both RF chains and computation can be reduced with a similar channel capacity compared with the conventional phased array. With the merits of low complexity and low consumption, the proposed massive MIMO scheme exhibits promising usage for green 5G base station applications. [ABSTRACT FROM AUTHOR]

Fish is currently considered a primary protein in the human diet, and the high demand for fish will stimulate the growth of aquaculture. However, a lack of high-quality fish feed (fishmeal) has led to a decline in the quality and yield of aquatic products. Therefore, an alternative high-quality protein source for fish meal is required to sustain the industry. This study assessed the effects of incorporating Spirulina platensis (SP) dried powder as a partial replacement for fishmeal and supplementing with S. platensis purified polysaccharides (PSP) on the growth, nutritional value, and health status of the largemouth bass, Micropterus salmoides, to address the challenges of fishmeal scarcity and promote sustainable development in fish aquaculture. Juveniles were fed four isonitrogenous and isolipidic diets containing SP at 0% (SP0), 3% (SP3) and 6% (SP6) and PSP at 0.3% for 56 days. The results showed that both the SP3 and SP6 groups displayed significantly (P < 0.05) improved growth performance and lower hepatosomatic indices than the control diet (SP0). Whole-body crude protein and protein efficiency significantly increased in both the SP3 and SP6 groups compared with SP0 (P < 0.05). Conversely, crude lipid content notably (P < 0.05) decreased in SP3 (5.96%) and SP6 (5.41%) in contrast to SP0 (6.59%). The muscle amino acid composition of the PSP, SP3, and SP6 groups also improved significantly (P < 0.05) compared to that of the SP0. Liver SOD activity was significantly increased from 1.11 U/mg in SP0 to 1.22–1.24 U/mg in SP3 and SP6 (P < 0.05), while MDA levels declined accordingly. Serum triglyceride levels were significantly lower in SP3 than in SP0 (P < 0.05) but remained stable in the SP6 and PSP groups. Low-density lipoprotein cholesterol decreased significantly in the SP3 and SP6 groups, but no significant effect was observed in the PSP group. Alanine aminotransferase activity was significantly (P < 0.05) lower in the PSP, SP3, and SP6 groups than in SP0. Aspartate aminotransferase activity in PSP and SP3 was significantly lower than in SP0 (P < 0.05), but showed no significant difference with SP6 (P > 0.05). Intestinal trypsin and amylase activities significantly improved in the PSP, SP3, and SP6 groups (P < 0.05), and lipase activities in PSP and SP3 increased significantly compared to those in SP0 (P < 0.05). The intestinal microbiome displayed significantly higher Shannon index scores for SP3 (0.83) and SP6 (0.93) than for SP0 (0.61). The relative abundances of the phylum Fusobacteria and genus Cetobacterium were significantly increased, whereas Proteobacteria and Plesiomonas were significantly decreased in the PSP and SP3 groups compared with that in SP0 (P < 0.05). The present study indicated that the replacement of fishmeal with 3–6% SP and 0.3% PSP addition could improve the growth performance, protein efficiency, muscle nutritional value, liver health, antioxidant capacity, intestinal digestive enzyme activity, and intestinal microbiota diversity of the largemouth bass. Therefore, the partial replacement of SP or the addition of PSP has great potential in promoting healthy aquaculture of largemouth bass. • Effects of adding Spirulina dried powder (SP) and polysaccharide (PSP) to the diet of Micropterus salmoides were assessed. • Including 3% and 6% SP in the diet led to enhanced growth performance and improved protein efficiency. • Both SP and PSP resulted in reduced lipid deposition, enhanced liver health, and increased antioxidant capacity. • Both SP and PSP led to improvements in gut digestive enzymes and enhanced the nutritional value of fish muscle. • Both SP and PSP promoted greater biodiversity in gut microbiota and an increase in beneficial species. [ABSTRACT FROM AUTHOR]