Design and Fabrication of W-Band Waveguide Slotted Array Antenna Based on Milling Process

A single-layer waveguide slotted array antenna is proposed for W-band applications. To eliminate the alignment errors, all structures including the radiation slots, radiation waveguides, and power divider network are realized in one layer based on the milling process, and a planar metal plate is employed to cover the bottom. For example, an 8 × 9 array is designed with 1-to-8 power divider network to validate the proposed technology. The effective radiation aperture size of the array is 24 mm × 21 mm, and the height is only 8 mm. The measured reflection coefficient of the antenna is larger than 3 GHz for S11 < −10 dB. The peak gain is 25.9 dBi, and the corresponding antenna efficiency is about 65%. All cross-polarization of the antenna array is less than −35 dB. The proposed array antenna features a simple structure, low cost, and easy implementation for W-band applications

Adaptive Control System Design and Experiment Study of Gas Flow Regulation System for Variable Flow Ducted Rockets

Variable flow ducted rockets (VFDRs) are promising candidates for propulsion systems in hypersonic vehicles because of their inherent advantages, such as high specific impulse, low weight, and high speed. The control of gas flow is essential for optimal VFDRs performance. However, the characteristics of gas flow regulation systems, such as anti-regulation, non-linearity, and parameter variation, make it difficult to construct gas flow controllers. Aiming at the above problems, we propose a compound control strategy integrating a novel second-order fuzzy adaptive tracking differentiator (SOA-TD) and an intelligent proportional-integral controller based on adaptive neuro-fuzzy inference system (ANFIS). First, a mathematical model of a gas flow regulation system was developed to analyze the control characteristics of VFDRs. Next, an ANFIS-based proportional-integral controller to developed to respond to the system’s time-varying characteristics. In addition, a novel SOA-TD was constructed to optimize the “arrange transient process” of instructions, which effectively suppressed anti-regulation of the gas flow without increasing response time. Finally, a hardware in loop (HIL) simulation device for VFDRs was established, and serial HIL simulation tests were carried out to verify the validation of the controller. The HIL simulation results indicate that our strategy exhibited a superior performance compared to traditional controllers in terms of adaptability, ability to suppress anti-regulation, and robustness, which is hoped to fulfill VFDRs’ thrust control requirements for a wide range of altitudes and Mach numbers in future engineering applications

An online speed profile generation approach for efficient airport ground movement

The precise guidance and control of taxiing aircraft based on four-dimensional trajectories (4DTs) has been recognised as a promising means to ensure safe and efficient airport ground movement in the context of ever growing air traffic demand. In this paper, a systematic approach for online speed profile generation is proposed. The aim is to generate fuel-efficient speed profiles respecting the timing constraints imposed by routing and scheduling, which ensures conflict-free movement of aircraft in the planning stage. The problem is first formulated as a nonlinear optimisation model, which uses a more flexible edge-based speed profile definition. A decomposed solution approach (following the framework of matheuristic) is then proposed to generate feasible speed profiles in real time. The decomposed solution approach reduces the nonlinear optimisation model into three tractable constituent problems. The control point arrival time allocation problem is solved using linear programming. The control point speed allocation problem is solved using particle swarm optimisation. And the complete speed profile between control points is determined using enumeration. Finally, improved speed profiles are generated through further optimisation upon the feasible speed profiles. The effectiveness and advantages of the proposed approach are validated using datasets of real-world airports

Alteration in bile acids profile in Large White pigs during chronic heat exposure.

Bile acids (BAs) are critical for cholesterol homeostasis and new roles in metabolism and endocrinology have been demonstrated recently. It remains unknown whether BA metabolism can be affected by heat stress (HS). The objective of this study was to describe the shifts in serum, hepatic and intestinal BA profiles induced by chronic HS. Twenty-seven Large White pigs weighing 40.8+/-2.7kg were assigned to one of the three treatments: a control group (CON, 23 degrees C), a HS group (33 degrees C), or a pair-fed group (PF, 23 degrees C and fed the same amount as HS group) for 21d. The concentrations of taurine-conjugated BAs (TUDCA and THDCA in serum and TCDCA, TUDCA, THDCA and THCA in liver) were decreased in HS and PF pigs. However, in HS pigs, a reduction in taurine-conjugated BAs (TCBA) correlated with decreased liver genes expression of BA synthesis, conjugation and uptake transport. BA regulated-genes (FXR, TGR5 and FGFR4) in HS pigs and TGR5, FGFR4 and KLbeta in PF pigs were down-regulated in liver. In ileum, total BAs and glycoursodeoxycholic acid concentrations were higher in HS pigs than other groups and PF group, respectively (P<0.05). TCBA (P=0.01) and tauroursodeoxycholic acid (P<0.01) were decreased in PF group. BA transporters (OSTalpha and MRP3) were up-regulated in HS pigs compared with CON and PF pigs, respectively (P<0.01). In cecum, ursodeoxycholic acid was higher in HS (P=0.02) group than CON group. The expression of apical sodium-coupled bile acid transporter (P=0.04) was lower in HS pigs than CON pigs, while OSTbeta (P<0.01) was greater in HS group than PF group. These results suggest that chronic HS suppressed liver activity of synthesis and uptake of TCBA, at least in part, which was independent of reduced feed intake

Downregulated SPESP1‐driven fibroblast senescence decreases wound healing in aged mice

Abstract Background Human dermal fibroblasts (HDFs) are essential in the processes of skin ageing and wound healing. However, the underlying mechanism of HDFs in skin healing of the elderly has not been well defined. This study aims to elucidate the mechanisms of HDFs senescence and how senescent HDFs affect wound healing in aged skin. Methods The expression and function of sperm equatorial segment protein 1 (SPESP1) in skin ageing were evaluated via in vivo and in vitro experiments. To delve into the potential molecular mechanisms by which SPESP1 influences skin ageing, a combination of techniques was employed, including proteomics, RNA sequencing, immunoprecipitation, chromatin immunoprecipitation and liquid chromatography‐mass spectrometry analyses. Clearance of senescent cells by dasatinib plus quercetin (D+Q) was investigated to explore the role of SPESP1‐induced senescent HDFs in wound healing. Results Here, we define the critical role of SPESP1 in ameliorating HDFs senescence and retarding the skin ageing process. Mechanistic studies demonstrate that SPESP1 directly binds to methyl‐binding protein, leading to Decorin demethylation and subsequently upregulation of its expression. Moreover, SPESP1 knockdown delays wound healing in young mice and SPESP1 overexpression induces wound healing in old mice. Notably, pharmacogenetic clearance of senescent cells by D+Q improved wound healing in SPESP1 knockdown skin. Conclusions Taken together, these findings reveal the critical role of SPESP1 in skin ageing and wound healing, expecting to facilitate the development of anti‐ageing strategies and improve wound healing in the elderly

Xylooligosaccharide-mediated gut microbiota enhances gut barrier and modulates gut immunity associated with alterations of biological processes in a pig model.

peer reviewedXylooligosaccharide (XOS) has tremendous prebiotic potentials for gut health, but the relevant mechanisms are unclear. Herein, we confirmed the positive effects of dietary XOS enhancing gut barrier in a pig model via suppressing the expression of pro-inflammatory cytokines (IL-6 and IL-8). Meanwhile, XOS increased beneficial microbes Lactobacillus and decreased potential pathogenic bacteria. Moreover, XOS augmented microbiota-derived metabolites (mainly butyrate, propionate, and secondary bile acid) to strengthen the gut barrier and regulate gut immunity through activating host G-protein coupled receptors 109a or inhibiting histone deacetylases. Furthermore, XOS attenuated IgA-production and antigen cross-presentation processes. In addition, XOS supplementation led to the alteration of cell proliferation, remodeling of the energy metabolism, activation processes of serial genes or proteins, increased molecular chaperones, and the enhanced ubiquitin-proteasome pathway in cecal cells. Collectively, these results suggest that XOS enhances gut barrier and modulates gut immunity by optimizing gut microbiota and their metabolites, which is associated with alterations of biological processes