In the design of flapping-wing micro-size air vehicles capable of hovering, wings serve as the primary source of hovering power, making the analysis of aerodynamics and aerodynamic efficiency ...crucial. Traditional quasi-steady models treat the wings as single rigid plane, neglecting the deformable characteristics of flexible wings. This paper proposes a multi-plane method that, in conjunction with various design parameters of flexible wings in a two-dimensional plane, analyzes their deformation characteristics under the assumption of multiple planes in three-dimensional space, and describes the deformation of wings during flapping. By combining the quasi-steady aerodynamic model, aerodynamic analysis of the deformed wings can be conducted. The relationship between the slack angle, wing flapping position, and wing deformation are analyzed, along with their effects on aerodynamics and aerodynamic efficiency. Experiments validate the deformation patterns of wings during flapping and compare the simulated aerodynamic forces with measured ones. The results indicate that wing deformation can be accurately described by adjusting the parameters in the multi-plane method and that the aerodynamic analysis using this method closely approximates the average lift results. Additionally, the multi-plane method establishes a connection between wing morphology and aerodynamic forces and efficiency, providing valuable insights for aerodynamic analysis.
Most of the driving mechanisms used in micro flapping wing vehicles are gear and linkage transmission mechanisms, which convert the unidirectional rotation of the motor into the reciprocating ...flapping of the driving mechanism. However, gear and linkage transmission mechanisms occupy a larger space and weight with certain energy losses. This article introduces a drive mechanism that is different from gear and linkage mechanisms, namely the string-based mechanism. In this study, the working principle and various parameters in string-based mechanisms are analyzed, and the flapping trajectory and amplitude of the mechanism is simulated. Following that, this article proposes an improved method of the cam mechanism, designs the trajectory of a cam mechanism, and a physical design is carried out with a driving mechanism width of 22 mm. Subsequently, the experiments are conducted to compare the flapping trajectory of the actual mechanism with the simulation trajectory, thereby verifying the simulation accuracy. The results prove that, in a string-based mechanism, the ratio of the radius of the pulley to the installation radius of the double-layer bearings has a direct impact on the flapping amplitude, and optimizing the design of cam mechanisms can effectively reduce the tensile and relaxation phenomena in string-based mechanisms. The above conclusion was verified in physical experiments, where the modified cam mechanism effectively reduced the stuck phenomenon in the string-based mechanism.
Visual Odometry (VO) systems are widely used to determine the position and orientation of a robot or camera in an unknown environment. They are deployed on resource-constrained platforms, such as ...drones, and virtual reality or augmented reality headsets. VO systems harnessing modern System-on-Chip (SoCs) with integrated Field Programmable Gate Array (FPGA) have the potential to improve overall performance. This paper explores the FPGA acceleration of sparse semi-direct VO kernels using High-level Synthesis (HLS). The selected sparse Semi-direct VO (SVO) system, since its conception, was developed to execute efficiently on low-power processors. We show that both computational and data transfer overheads between the processing cores and the accelerators on the reconfigurable fabric need to be optimized to obtain better end-to-end performance. The additional data movement incurred when using an FPGA accelerator is due to the sparse computational nature together with random memory access patterns of the kernels. This paper shows that state-of-the-art HLS tools are not yet able to perform the required optimizations automatically. These tools usually target successful application kernels with dense computational patterns and regular memory access. In this paper we propose three, potentially general, methods to reduce the data transfer between the processing cores and the customised hardware kernels on the FPGA; these methods are: (a) approximation based on domain-specific knowledge, (b) lossless image compression, and (c) the use of on-the-fly computation. We present a case study of the use of these methods on SVO, a state-of-the-art sparse VO system with a semi-direct front-end. We demonstrate that our proposed methods can reduce data transfer overhead to achieve better end-to-end performance and that they can be applied not only when using standard Xilinx tools, but also with other state-of-the-art HLS tools, such as HeteroFlow. Compared to the baseline performance of the original SVO software on Arm processors, our proposed methods enable the Xilinx SDSoC and HeteroFlow designs to achieve a speedup of Formula Omitted and Formula Omitted, respectively, without noticeable accuracy loss. The Xilinx SDSoC and HeteroFlow designs also achieve a Formula Omitted and Formula Omitted improvement in energy efficiency, respectively, on a Xilinx Zynq Ultrascale+ SoC with Arm A53 cores and integrated FPGA. Compared to the SVO software baseline running on the Intel Xeon system, our proposed methods enable the Xilinx SDSoC and HeteroFlow designs to achieve Formula Omitted and Formula Omitted improvement in energy efficiency, respectively.
This study aimed to investigate the effects of bile acids (BAs) supplementation on fatty liver hemorrhagic syndrome (FLHS), production performance, and physiological and quality characteristics of ...laying hen eggs. Sixty Sanhuang laying hens, aged 28 weeks, were randomly allocated to six dietary treatments over a 4-week period, including the control (CON) group (feeding basal diet), the high-fat diet (HFD)-treated group (basal diet containing 10% soybean oil), and HFD supplemented with 0.01% and 0.02% of chenodeoxycholic acid (CDCA) or hyodeoxycholic acid (HDCA) groups. Production performance, egg quality, liver morphology, serum biochemical indexes, antioxidant capacity, proinflammatory cytokines, and intestinal microbiota were evaluated. The average body weight in 0.01% CDCA was larger than in the HFD group (p < 0.05). Eggshell Thickness in the CON group was greater than in the HFD, 0.01% CDCA, and HDCA groups (p < 0.05). Albumen height in the 0.02% HDCA group was higher than the HFD group (p < 0.05). Eggshell weight in the HFD group was less than the CON group (p < 0.05). Haugh unit (HU) in the HDCA group was larger than the HFD group (p < 0.05). Albumen weight in the 0.02% HDCA group was greater than the CON and HFD groups (p < 0.05). In the HFD group, the levels of triglyceride (TG), total cholesterol (TC), and low-density lipo-protein cholesterol (LDL-C) were surpassing the other groups (p < 0.05). The levels of catalase (CAT) and total superoxide dismutase (T-SOD) in the HFD group was smaller than the other groups (p < 0.05). The level of malondialdehyde (MDA) in the HFD group was higher than in the other groups (p < 0.05). Tumor necrosis factor-α (TNF-α) levels were larger in the HFD group than in the other groups (p < 0.05). The 16S rRNA sequencing analysis indicated significant variations in the relative abundance of specific bacterial populations among the different treatment groups. The treatment and CON groups exhibited a higher presence of bacteria that inhibit host energy absorption or promote intestinal health such as Firmicutes, Bacteroidetes, and Ruminococcus, whereas the HFD group showed an increased prevalence of potentially pathogenic or deleterious bacteria, such as Desulfovibrio spp. In conclusion, the supplementation of BAs in poultry feed has been demonstrated to effectively mitigate the detrimental effects of FLHS in laying hens. This intervention regulates lipid metabolism, bolsters antioxidant defenses, reduces inflammation, and modulates the gut microbiota, offering a novel perspective on the application of BAs in the poultry industry.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Neonatal hypoxia can induce the persisting brain dysfunctions and subsequently result in the behavioral abnormalities in adulthood. Improving mitochondrial functions were suggested as the effective ...strategy for brain functional recovery. In this study, we tested the effects of physical exercise, a well-established way benefits mitochondrion, for its functions to prevent hypoxia induced adult behavioral dysfunctions and the underlying molecular mechanism. Mice was induced with hypoxia and treadmill running were then administrated until the adulthood. The treadmill running resulted in the improved behavioral performance in depressive and anxiety tests together with the enhancement of hippocampal neurogenesis. We then detected treadmill running restored the mitochondrial morphology in adult neural stem cells (NSCs) as well as the ATP production in hippocampal tissue. In addition, activity of AMPK, which playing key roles in regulating mitochondrial functions, was also elevated by treadmill running. Blockage of AMPK with selective inhibitor compound C prohibited effects of treadmill running in attenuating neonatal hypoxia induced neurogenic impairment and antidepressant behavioral deficits in adulthood. In conclusion, treadmill running could prevent neonatal hypoxia induced adult antidepressant dysfunctions and neurogenic dampening via AMPK-mediated mitochondrial regulation.
•Treadmill running restored early hypoxia induced depressive symptoms in adulthood.•Treadmill running promoted adult hippocampal neurogenesis in adult mice with early life hypoxic stress.•AMPK regulates treadmill running induced neuroprotection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Few studies on the humoral immune responses in human during natural influenza infection have been reported. Here, we used serum samples from pandemic 2009 H1N1 influenza infected patients to ...characterize the humoral immune responses to influenza during natural infection in humans. We observed for the first time that the pandemic 2009 H1N1 influenza induced influenza A-specific IgM within days after symptoms onset, whereas the unit of IgG did not changed. The magnitude of influenza A-specific IgM antibodies might have a value in predicting the rate of virus clearance to some degree. However, the newly developed IgM was not associated with hemagglutination inhibition (HI) activities in the same samples but correlated with HI activities of subsequently collected sera which were mediated by IgG antibodies, indicating that IgM was critical for influenza infection and influences subsequent IgG antibody responses. These findings provide new important insights on the human immunity to natural influenza infection.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this article, we report a low-threshold random laser enhanced by TiN nanoparticles (NPs) suspended randomly in gain solutions. Results show that the random laser with TiN NPs has a lower threshold ...than the random laser with TiO
NPs and the underlying mechanisms are discussed in detail. The localized surface plasmon resonance of individual TiN NPs increases the pump efficiency and strengthens the fluorescence amplification efficiency of the DCM. The multiple scattering of integral TiN NPs extends the dwelling time of light in random systems, which provides more possibilities for the light amplification in the gain medium. Then, the random laser threshold as a function of the number density of TiN NPs is studied. Results show that the optimum number density of TiN NPs for the lowest-threshold random lasers is about 1.468 × 10
ml
. When we substitute the ethanol solution with the nematic liquid crystal (NLC), the random laser threshold can be further decreased to 5.11 µJ/pulse, which is about 7.7 times lower than that of DCM dye solution with TiN NPs under the same conditions. These findings provide a cost-effective strategy for the realization of low-threshold random lasers with high-quality.
Post-traumatic stress disorder (PTSD) is a serious psychiatric disorder characterized by hyper-response to environmental cues as well as the associated depressive and cognitive dysfunctions. ...According to the key roles of hippocampus for cognitive and emotional regulation, improving hippocampal functions, particularly hippocampal neural plasticity, is the necessary pathway to attenuate the core symptoms of PTSD. The effects of the alternative therapies such as exercise and natural compounds to reduce PTSD symptoms and promote adult hippocampal neurogenesis have been widely demonstrated. However, what is the effect of combining the exercise with traditional Chinese medical compounds remains unknown. In current study, we evaluated the effects of catalpol, which showed the pro-neurogenic effects in previous report, in regulating exercise-mediated PTSD therapeutic effects. With behavioral tests, we found that catalpol treatment promoted the effects of exercise to reduce the response of mice to dangerous cues, and simultaneously enhanced the antidepressant and cognitive protection effects. Moreover, by immunofluorescence we identified that catalpol promoted exercise-mediated hippocampal neurogenesis by enhancing the neural differentiation and mature neuronal survive. We further found that the promote effects of catalpol to exercise-induced environmental hyper-response, antidepressant effects and cognitive protective effects were all compromised by blocking neurogenesis with temozolomide (TMZ). This result indicates that hippocampal neurogenesis is prerequisite for catalpol to promote exercise-mediated brain functional improvement in PTSD model. In conclusion, our research identified the new function of natural compounds catalpol to promote the exercise-mediated brain functional changes in PTSD model, which depend on its effect promoting adult hippocampal neurogenesis.
Visual Odometry (VO) systems are widely used to determine the position and orientation of a robot or camera in an unknown environment. They are deployed on resource-constrained platforms, such as ...drones and Virtual Reality (VR) or Augmented Reality (AR) headsets. VO systems harnessing modern System-on-Chip (SoCs) with integrated Field Programmable Gate Array (FPGA) have the potential to improve the overall systems performance. This paper explores the FPGA acceleration of sparse VO kernels using High-level Synthesis (HLS) as this kind of VO system has been designed to use with low-power SoCs. We show that both computational and data transfer overheads between the processing cores of the CPU of the SoC and the accelerators on the FPGA need to be optimized to obtain better end-to-end performance. This is a result of the additional data movement incurred when using an FPGA accelerator and also because of the sparse computational nature with predictable or random memory access patterns of the kernels involved. However, state-of-the-art HLS tools are not yet able to perform the required optimizations automatically because they usually assume that the kernels to be accelerated have dense computational patterns with regular memory access. In this paper we propose three, potentially generic, methods to reduce the data transfer between the CPU and the customised hardware kernels on the FPGA; these methods are: (a) approximation based on domain-specific knowledge, (b) image compression, and (c) the use of on-the-fly computation. We present a case study of the use of these methods on SVO, a state-of-the-art sparse VO system with a semi-direct front-end. We demonstrate that our proposed methods can reduce data transfer overhead to achieve better end-to-end performance and that they can be applied not only when using standard Xilinx HLS tools but also with other state-of-the-art HLS tools, such as HeteroFlow. Compared to the baseline performance of the original SVO software on an Arm CPU, our proposed methods assist the HLS and HeteroFlow designs to achieve a speedup of 2.4x and 2.14x, respectively, without noticeable accuracy loss. The HLS and HeteroFlow designs also achieve a 1.85x and 1.89x, respectively, improvement in energy efficiency on the SoC system used. Compared to the SVO software baseline running on the Intel Xeon CPU, our proposed methods assist the HLS and HeteroFlow designs to achieve 8.2x and 8.3x improvement in energy efficiency, respectively.
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