The thermal comfort of an enclosed room with air conditioner and air-distribution duct coupling can be studied, and the parameters of a split-fiber air conditioner can be optimized on the basis of ...studying the thermal comfort of various parts of the human body. In this paper, a room model with a distributed air conditioner was proposed. First, the rationality of the three thermal comfort characterization models of predict mean vote (PMV), predicted percentage of dissatisfied (PPD), and percentage of dissatisfied (PD) were verified through experiments and simulations. Then, the temperature and thermal comfort of various parts of the human body were explored when the air-distribution duct had different openings and different positions of the air outlet. The simulation results showed that compared with other situations, when the split-fiber air conditioner had three rows of holes (5-o’clock, 6-o’clock, 7-o’clock) and the air outlet was located in the middle of the right wall of the human body, the PMV, PPD, and PD of the measuring points around the human body fluctuated less, the indoor temperature field distribution fluctuated less, and there was no wind feeling around the human body, which can better meet the needs of human thermal comfort.
Macropinocytosis, an evolutionarily conserved mechanism mediating nonspecific bulk uptake of extracellular fluid, has been ascribed diverse functions. How nascent macropinosomes mature after ...internalization remains largely unknown. By searching for proteins that localize on macropinosomes during the Rab5-to-Rab7 transition stage in Dictyostelium, we uncover a complex composed of two proteins, which we name PripA and TbcrA. We show that the Rab5-to-Rab7 conversion involves fusion of Rab5-marked early macropinosomes with Rab7-marked late macropinosomes. PripA links the two membrane compartments by interacting with PI(3,4)P
and Rab7. In addition, PripA recruits TbcrA, which acts as a GAP, to turn off Rab5. Thus, the conversion to Rab7 is linked to inactivation of the upstream Rab5. Consistently, disruption of either pripA or tbcrA impairs Rab5 inactivation and macropinocytic cargo processing. Therefore, the PripA-TbcrA complex is the central component of a Rab GAP cascade that facilitates programmed Rab switch and efficient cargo trafficking during macropinosome maturation.
We consider the Vlasov–Poisson–Landau system, a classical model for a dilute collisional plasma interacting through Coulombic collisions and with its self-consistent electrostatic field. We establish ...global stability and well-posedness near the Maxwellian equilibrium state with decay in time and some regularity results for small initial perturbations, in any general bounded domain (including a torus as in a tokamak device), in the presence of specular reflection boundary condition. We provide a new improved
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energy estimate combines only with
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estimate for the ultra-parabolic equation.
Temporal and spatial vortex shedding evolution for flow around a circular cylinder near a plane boundary is investigated using three-dimensional direct numerical simulation, with a parameter space of ...boundary layer thickness-to-diameter δ/D = 0–1.4, gap-to-diameter G/D = 0.4 and Re = 350. For each δ/D, three consecutive wake stages are divided with time based on the dominated flow structures – mode A and mode B, of which spanwise wavelength is quantitatively measured by the autocorrelation function (ACF). In the first stage, mode A structures spread from two spanwise ends to the middle region and from upstream to downstream wake simultaneously. This stage is only dominated by ordered mode A structures and shows a weak three-dimensionality. In the second stage, mode B structures start to propagate in the same spanwise but opposite streamwise direction as mode A, and squeeze the mode A region until its disappearance. A mixture of mode A and mode B structures dominate the second stage and the flow is in the strongest three-dimensionality. In the third stage, the wake transits from a symmetric distribution of ordered mode B structure to an asymmetric distribution of disordered mode B structure, showing a relatively strong three-dimensionality. The typical vortex shedding patterns are analyzed by dynamic mode decomposition (DMD). When δ/D > 0, the dominant mode frequency (f0) of vortex shedding, larger than that of an isolated cylinder, decreases with the increase of δ/D. Due to suppression of the lower-surface vortex shedding, the flow structures with f0 are greatly reduced both in size and regularity with the increase of δ/D. Scattered mode components are reduced and the energy of each mode is more concentrated with increasing δ/D.
•3-D flow characteristics around a circular cylinder close to a bottom wall are investigated.•Spanwise wavelength of streamwise vortices and flow three-dimensionality are quantitatively identified.•Three stages of the wake transition are observed based on different dominated flow structures.•Streamwise and spanwise propagation of mode A and mode B are examined.
Beauvericin (BEA), a naturally occurring cyclic peptide with good pharmacological activity, has been widely explored in anticancer research. Although BEA is toxic, studies have demonstrated its ...antioxidant activity. However, to date, the antioxidant mechanisms of BEA remain unclear. Herein, we conducted a comprehensive and detailed study of the antioxidant mechanism of BEA using an untargeted metabolomics approach, subsequently validating the results. BEA concentrations of 0.5 and 1 μM significantly inhibited H
O
-induced oxidative stress (OS), decreased reactive oxygen species levels in PC-12 cells, and restored the mitochondrial membrane potential. Untargeted metabolomics indicated that BEA was primarily involved in lipid-related metabolism, suggesting its role in resisting OS in PC-12 cells by participating in lipid metabolism. BEA combated OS damage by increasing phosphatidylcholine, phosphatidylethanolamine, and sphingolipid levels. In the current study, BEA upregulated proteins related to the PI3K/AKT/mTOR pathway, thereby promoting cell survival. These findings support the antioxidant activity of BEA at low concentrations, warranting further research into its pharmacological effects.
Intercropping, a diversified planting pattern, increases land use efficiency and farmland ecological diversity. We explored the changes in soil physicochemical properties, nutrient uptake and ...utilization, and microbial community composition in wide-strip intercropping of maize and peanut.
The results from three treatments, sole maize, sole peanut and intercropping of maize and peanut, showed that intercropped maize had a marginal advantage and that the nutrient content of roots, stems and grains in side-row maize was better than that in the middle row of intercropped maize and sole maize. The yield of intercropped maize was higher than that of sole cropping. The interaction between crops significantly increased soil peroxidase activity, and significantly decreased protease and dehydrogenase activities in intercropped maize and intercropped peanut. The diversity and richness of bacteria and fungi decreased in intercropped maize rhizosphere soil, whereas the richness of fungi increased intercropped peanut. RB41, Candidatus-udaeobacter, Stropharia, Fusarium and Penicillium were positively correlated with soil peroxidase activity, and negatively correlated with soil protease and dehydrogenase activities. In addition, intercropping enriched the functional diversity of the bacterial community and reduced pathogenic fungi.
Intercropping changed the composition and diversity of the bacterial and fungal communities in rhizosphere soil, enriched beneficial microbes, increased the nitrogen content of intercropped maize and provided a scientific basis for promoting intercropping in northeastern China.
Flow-induced vibrations (FIV) of an equilateral triangular prism are numerically studied using the immersed boundary method in a parametric space of α=0°–60° and U∗=U∕fnD=1–20, with α=0°(60°) ...representing the configuration of one vertex facing upstream (downstream). The Reynolds number based on the effective edge length perpendicular to the incoming flow is Re = 200 and the mass ratio is m∗=4m∕3ρD2=2.0. In above, U is the incoming flow velocity, fn is the natural frequency of the prism, D is the edge length of the prism, m is the prism mass and ρ is the fluid density. Three different vibration regimes, i.e., VIV at α=0°–25°, combined VIV and galloping at α=30°–40°, and galloping at α=45°–60°, are confirmed. In the VIV regime, the vibration amplitude is relatively small and the vibration frequency linearly increases with U∗, signifying the non-locked response. In the combined VIV and galloping regime, the amplitude is determined by the competition of the VIV and galloping modes, with large amplitude appearing when the galloping mode dominates. In the galloping regime, the vibration amplitude monotonically increases with U∗, with a lower-than-unity vibration frequency. Moreover, seven wake modes are observed in the examined α and U∗ ranges: 2S mode, 2S(P) mode, P+S mode, P+S/2S mode, the competition mode (CM), and the galloping modes (miS+niS and mS+nS). In CM, the VIV and galloping modes compete each other. In the galloping modes, the vortices are arranged in a ‘V’ shape. The effects of the streamwise vibration on the transverse responses is significant only in the combined VIV and galloping regime.
•Three different vibration regimes, i.e., VIV, combined VIV and galloping, and galloping, are observed.•Seven wake modes are observed in the examined α and U⁎ ranges.•The effects of the streamwise vibration on the transverse responses is significant only in the combined VIV and galloping regime.
In this study, restorative environment theory and virtual reality (VR) technology were combined to build different 3D dynamic VR interactive scenes. We discuss the effects of a VR restorative ...environment on the emotional and cognitive recovery of individuals with mild-to-moderate anxiety and depression. First, we built a VR restorative garden scene, divided into four areas: forest, lawn, horticultural planting, and water features. The scene was verified to have a good recovery effect in 26 participants. Then, 195 participants with mild-to-moderate anxiety and depression were selected as experimental subjects. Through psychological testing and EMG (Electromyography) and EEG (Electroencephalography) data feedback, we further explored the differences in the sense of presence in VR restorative scenes and their effect on individual emotional and cognitive recovery. The results showed that (1) both the restorative environment images and the VR scenes had a healing effect (the reduction in negative emotions and the recovery of positive emotions and cognition), with no difference in the subjective feeling of recovery among the different scenes, but the recovery score of the VR urban environment was higher than that of the natural environment (differing from the results in real environments); (2) a high sense of presence can be experienced in different VR scenes, and interactive activities in VR scenes can provide a great presence experience; (3) the recovery effects of VR restorative environment on emotion and self-efficacy are realized through the presence of VR scenes; (4) a VR restorative environment is helpful for the emotional improvement and cognitive recovery of individuals with mild-to-moderate anxiety and depression. VR urban scenes also have good recovery effects. In terms of cognitive recovery, self-efficacy improved significantly. In addition, from the perspective of EEG indicators, the VR restorative scene experience activated the prefrontal lobe, which is conducive to cognitive recovery in individuals with mild-to-moderate anxiety and depression. In terms of emotional improvement, negative emotions were significantly reduced in the different VR scene groups. In conclusion, we further explored ways to help individuals with mild-to-moderate anxiety and depression, in order to promote the development and application of mental health.
Vortex-induced vibrations of two inline circular cylinders in proximity to a stationary wall are numerically studied using the immersed boundary method at a Reynolds number of 100. Two cylinders, ...having the same degree of freedom (DOF), can oscillate only in the transverse direction (1-DOF) or in both the transverse and streamwise directions (2-DOF). The center-to-center spacings (L) of the two cylinders are 1.5D, 3.0D and 5.0D, respectively, while the gaps (G) between the wall and the cylinders are 0.6D, 1.5D and ∞, respectively. Here, D is the diameter of the cylinders. The mass ratio is 2.0 and the reduced velocity varies from 2.0 to 15.0, with the minimum interval of 0.1. We observe that the responses of the two cylinders are significantly influenced by the presence of a stationary wall, compared with those without near-wall effects. First, several hysteretic regions are observed at different gap ratios and spacing ratios. Second, the streamwise vibration amplitude is comparable to the transverse one in the 2-DOF cases. Third, the trajectories can be oval-shaped, figure-of-eight-shaped, quasi-periodic or chaotic depending on G and L. In the simulated parametric space, we divide the vibration response of the two cylinders into different branches, i.e., two stationary branches (SB-I and SB-II), two vibration branches (VB-I and VB-II), and one collision branch (CB). The features such as vibration amplitudes, vibration frequencies, wake patterns, fluid forces, mean position shifts, and vibration trajectories in each branch are explored in detail. Furthermore, the mechanisms of the excitation of the large-amplitude vibrations in both the streamwise and transverse directions are investigated.
•The VIV responses of the two tandem cylinders are significantly influenced by the presence of a stationary wall.•Hysteresis exists at different gap ratios and spacing ratios.•The streamwise vibration amplitude is comparable to the transverse one in the 2DOF near-wall VIV.•The trajectories of the two tandem cylinders can be periodic (oval-shape or figure-of-eight), quasi-periodic or chaotic.
In this paper, we present direct numerical simulations (DNS) of the three-dimensional flow around a circular cylinder near a stationary wall at the Reynolds number of 500. The gap (G) between the ...cylinder surface and the stationary wall varies in the range of 0–3.0D where D is the cylinder diameter. We observe that the proximity wall significantly affects the flow topology around the cylinder, which is characterized by the asymmetric wake, upward gap flow, and strong interactions of the cylinder vortices with the wall-generated boundary layer. Three flow regimes are identified with variations of the fluid forces and vortex dynamics. (i) Steady regime: at G/D < 0.3, vortex shedding is suppressed in the near wake, and scattered streamwise vortices form in the far wake where the upper side shear layer meets the stationary wall. No fluctuating forces act on the cylinder. (ii) Biased unsteady regime: at 0.3 ≤ G/D < 1.5, the gap flow deflects upward and the vortices shed from the gap side are significantly suppressed. The cylinder has enlarged fluctuating drag and lift forces with identical dominant frequencies. (iii) Parallel unsteady regime: at G/D ≥ 1.5, vortices shed from both sides of the cylinder are of almost identical intensities while the gap flow is approximately parallel to the wall. The vortex dynamics approaches that of an isolated circular cylinder in unconfined flows. Flow features of each regime are illuminated through the flow fields, vorticity contours, statistics of the enstrophies and gap flow, and pressure distribution on the cylinder surface. Finally, we investigate the critical gap ratio for the onset of the vortex-shedding of the upper shear layer and discuss the underlying physics. Moreover, we observe that the occurrence of the second harmonic lift and fundamental drag frequencies are resulted from the asymmetric wake because of the proximity of the stationary wall.
•Direct numerical simulations of the three-dimensional flow past around a circular cylinder near a stationary wall at Re = 500 ere were conducted.•According to the variations of the fluid forces and vortex dynamics, three flow regimes are identified.•Flow features of each regime are illuminated thoroughly.
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