| 1. |
- Guo (郭佳诚), Jiacheng, et al.
(författare)
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Vortex dynamics and fin-fin interactions resulting in performance enhancement in fish-like propulsion
- 2023
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Ingår i: Physical Review Fluids. - 2469-990X. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- The leading-edge vortex (LEV) formation on the caudal fin (CF) has been identified as playing a key role in efficient lift-based thrust production of fish-like propulsion. The enhancement of the CF LEV through its interaction with vortices formed upstream due to a median fin with a distinct shape is the focus of this paper. High-speed, high-fidelity videos and particle imaging velocimetry (PIV) were obtained from rainbow trout during steady forward swimming to visualize the undulatory kinematics and two-dimensional flow behavior. Body kinematics are quantified using a traveling-wave formulation that is used to prescribe the motion of a high-fidelity three-dimensional surface model of the fish body for a computational fluid dynamics (CFD) study. The pressure field of the CFD result is compared and validated with the PIV result from the experiment. Using CFD, the vortex forming and shedding behaviors of the anal fin (AF) and their capturing and interaction with the trunk (TK) and the CF are visualized and examined. Coherent AF-bound LEVs are found to form periodically, leading to thrust production of the AF. The vortices subsequently shed from the AF are found to help stabilize and reinforce the LEV formation on the CF by aiding LEV initiation at stroke reversal and enhancing LEV during a tail stroke, which leads to enhancement of lift-based thrust production. The CF is found to shed vortex tubes (VTs) that create backward-facing jets, and the ventral-side VT and the associated backward jets are both strengthened by vortices shed by the AF. An additional benefit of the AF is found to be reduction of body drag by reducing the lateral crossflow that leads to loss of beneficial pressure gradient across the body. Through varying AF-CF spacing and AF height, we find that CF thrust enhancement and TK drag reduction due to the AF are both affected by the position and size of the AF. The position and area of the AF that led to the most hydrodynamic benefit are found to be the original, anatomically accurate position and size. In this paper, we demonstrate the important effect of vortex interaction among propulsive surfaces in fish-like propulsion.
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| 2. |
- He, Haoran, et al.
(författare)
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Deciphering microbiomes dozens of meters under our feet and their edaphoclimatic and spatial drivers
- 2024
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Ingår i: Global Change Biology. - 1354-1013. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- Microbes inhabiting deep soil layers are known to be different from their counterpart in topsoil yet remain under investigation in terms of their structure, function, and how their diversity is shaped. The microbiome of deep soils (>1 m) is expected to be relatively stable and highly independent from climatic conditions. Much less is known, however, on how these microbial communities vary along climate gradients. Here, we used amplicon sequencing to investigate bacteria, archaea, and fungi along fifteen 18-m depth profiles at 20–50-cm intervals across contrasting aridity conditions in semi-arid forest ecosystems of China's Loess Plateau. Our results showed that bacterial and fungal α diversity and bacterial and archaeal community similarity declined dramatically in topsoil and remained relatively stable in deep soil. Nevertheless, deep soil microbiome still showed the functional potential of N cycling, plant-derived organic matter degradation, resource exchange, and water coordination. The deep soil microbiome had closer taxa–taxa and bacteria–fungi associations and more influence of dispersal limitation than topsoil microbiome. Geographic distance was more influential in deep soil bacteria and archaea than in topsoil. We further showed that aridity was negatively correlated with deep-soil archaeal and fungal richness, archaeal community similarity, relative abundance of plant saprotroph, and bacteria–fungi associations, but increased the relative abundance of aerobic ammonia oxidation, manganese oxidation, and arbuscular mycorrhizal in the deep soils. Root depth, complexity, soil volumetric moisture, and clay play bridging roles in the indirect effects of aridity on microbes in deep soils. Our work indicates that, even microbial communities and nutrient cycling in deep soil are susceptible to changes in water availability, with consequences for understanding the sustainability of dryland ecosystems and the whole-soil in response to aridification. Moreover, we propose that neglecting soil depth may underestimate the role of soil moisture in dryland ecosystems under future climate scenarios.
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| 3. |
- Xu, Xiaoran, et al.
(författare)
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Applications of Boron Cluster Supramolecular Frameworks as Metal-Free Chemodynamic Therapy Agents for Melanoma
- 2023
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Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829.
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Tidskriftsartikel (refereegranskat)abstract
- Chemodynamic therapy (CDT) is a highly targeted approach to treat cancer since it converts hydrogen peroxide into harmful hydroxyl radicals (OH & BULL;) through Fenton or Fenton-like reactions. However, the systemic toxicity of metal-based CDT agents has limited their clinical applications. Herein, a metal-free CDT agent: 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12H12]2-(TPT@ B12H12) is reported. Compared to the traditional metal-based CDT agents, TPT@B12H12 is free of metal avoiding cumulative toxicity during long-term therapy. Density functional theory (DFT) calculation revealed that TPT@B12H12 decreased the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. Mechanismly, the theory calculation indicated that both [B12H12]-& BULL; and [TPT-H]2+ have the capacity to decompose hydrogen into 1O2, OH & BULL;, and O2-& BULL;. With electron paramagnetic resonance and fluorescent probes, it is confirmed that TPT@B12H12 increases the levels of 1O2, OH & BULL;, and O2-& BULL;. More importantly, TPT@B12H12 effectively suppress the melanoma growth both in vitro and in vivo through 1O2, OH & BULL;, and O2-& BULL; generation. This study specifically highlights the great clinical translational potential of TPT@B12H12 as a CDT reagent. 2,4,6-Tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12H12]2-(TPT@B12H12), a metal-free chemodynamic therapy (CDT) agent, decreases the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. More importantly, TPT@B12H12 effectively suppress the melanoma growth both in vitro and in vivo through 1O2, OH & BULL;, and O2-& BULL; generation. image
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| 4. |
- Xu, Xiaoran, et al.
(författare)
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Applications of Boron Cluster Supramolecular Frameworks as Metal-Free Chemodynamic Therapy Agents for Melanoma
- 2024
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Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 20:4
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Tidskriftsartikel (refereegranskat)abstract
- Chemodynamic therapy (CDT) is a highly targeted approach to treat cancer since it converts hydrogen peroxide into harmful hydroxyl radicals (OH & BULL;) through Fenton or Fenton-like reactions. However, the systemic toxicity of metal-based CDT agents has limited their clinical applications. Herein, a metal-free CDT agent: 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12H12]2-(TPT@ B12H12) is reported. Compared to the traditional metal-based CDT agents, TPT@B12H12 is free of metal avoiding cumulative toxicity during long-term therapy. Density functional theory (DFT) calculation revealed that TPT@B12H12 decreased the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. Mechanismly, the theory calculation indicated that both [B12H12]-& BULL; and [TPT-H]2+ have the capacity to decompose hydrogen into 1O2, OH & BULL;, and O2-& BULL;. With electron paramagnetic resonance and fluorescent probes, it is confirmed that TPT@B12H12 increases the levels of 1O2, OH & BULL;, and O2-& BULL;. More importantly, TPT@B12H12 effectively suppress the melanoma growth both in vitro and in vivo through 1O2, OH & BULL;, and O2-& BULL; generation. This study specifically highlights the great clinical translational potential of TPT@B12H12 as a CDT reagent. 2,4,6-Tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12H12]2-(TPT@B12H12), a metal-free chemodynamic therapy (CDT) agent, decreases the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. More importantly, TPT@B12H12 effectively suppress the melanoma growth both in vitro and in vivo through 1O2, OH & BULL;, and O2-& BULL; generation. image
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| 5. |
- Zhang, Lixiu, et al.
(författare)
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Advances in the Application of Perovskite Materials
- 2023
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Ingår i: NANO-MICRO LETTERS. - : SHANGHAI JIAO TONG UNIV PRESS. - 2311-6706. ; 15:1
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Forskningsöversikt (refereegranskat)abstract
- Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices (solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices (artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
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| 6. |
- Zhang, Wei, et al.
(författare)
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An efficient tree-topological local mesh refinement on Cartesian grids for multiple moving objects in incompressible flow
- 2023
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Ingår i: Journal of Computational Physics. - : Elsevier BV. - 0021-9991 .- 1090-2716. ; 479
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Tidskriftsartikel (refereegranskat)abstract
- This paper develops a tree-topological local mesh refinement (TLMR) method on Cartesian grids for the simulation of bio-inspired flow with multiple moving objects. The TLMR nests refinement mesh blocks of structured grids to the target regions and arrange the blocks in a tree topology. The method solves the time-dependent incompressible flow using a fractional-step method and discretizes the Navier-Stokes equation using a finite-difference formulation with an immersed boundary method to resolve the complex boundaries. When iteratively solving the discretized equations across the coarse and fine TLMR blocks, for better accuracy and faster convergence, the momentum equation is solved on all blocks simultaneously, while the Poisson equation is solved recursively from the coarsest block to the finest ones. When the refined blocks of the same block are connected, the parallel Schwarz method is used to iteratively solve both the momentum and Poisson equations. Convergence studies show that the algorithm is second-order accurate in space for both velocity and pressure, and the developed mesh refinement technique is benchmarked and demonstrated by several canonical flow problems. The TLMR enables a fast solution to an incompressible flow problem with complex boundaries or multiple moving objects. Various bio-inspired flows of multiple moving objects show that the solver can save over 80% computational time, proportional to the grid reduction when refinement is applied.
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