| 281. |
- Gou, De Hai, et al.
(författare)
-
Inhibition of copper transporter 1 prevents α-synuclein pathology and alleviates nigrostriatal degeneration in AAV-based mouse model of Parkinson's disease
- 2021
-
Ingår i: Redox Biology. - : Elsevier BV. - 2213-2317. ; 38
-
Tidskriftsartikel (refereegranskat)abstract
- The formation of α-synuclein aggregates is a major pathological hallmark of Parkinson's disease. Copper promotes α-synuclein aggregation and toxicity in vitro. The level of copper and copper transporter 1, which is the only known high-affinity copper importer in the brain, decreases in the substantia nigra of Parkinson's disease patients. However, the relationship between copper, copper transporter 1 and α-synuclein pathology remains elusive. Here, we aim to decipher the molecular mechanisms of copper and copper transporter 1 underlying Parkinson's disease pathology. We employed yeast and mammalian cell models expressing human α-synuclein, where exogenous copper accelerated intracellular α-synuclein inclusions and silencing copper transporter 1 reduced α-synuclein aggregates in vitro, suggesting that copper transporter 1 might inhibit α-synuclein pathology. To study our hypothesis in vivo, we generated a new transgenic mouse model with copper transporter 1 conditional knocked-out specifically in dopaminergic neuron. Meanwhile, we unilaterally injected adeno-associated viral human-α-synuclein into the substantia nigra of these mice. Importantly, we found that copper transporter 1 deficiency significantly reduced S129-phosphorylation of α-synuclein, prevented dopaminergic neuronal loss, and alleviated motor dysfunction caused by α-synuclein overexpression in vivo. Overall, our data indicated that inhibition of copper transporter 1 alleviated α-synuclein mediated pathologies and provided a novel therapeutic strategy for Parkinson's disease and other synucleinopathies.
|
|
| 282. |
|
|
| 283. |
|
|
| 284. |
- Han, Meng, et al.
(författare)
-
Experimental study of the effect of air split ratio on thermoacoustic instability in a centrally-staged swirl burner
- 2022
-
Ingår i: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 34:6
-
Tidskriftsartikel (refereegranskat)abstract
- This study focuses on one of the critical design parameters of lean premixed (LPM) combustors-the air split ratio (ASR) between the pilot and main stages. The effect of the air split ratio on thermoacoustic instability is experimentally studied based on a centrally staged model combustor. It is found that the thermoacoustic instability is suppressed with the ASR higher than 20%. The acoustic modes of ASR lower than 20% are dominated by the main stage mode, while the others are controlled by the pilot stage mode. The time-averaged flame shapes and the flame dynamics are processed and discussed. With the increase in ASR, the pilot flame becomes longer, whereas the main flame becomes shorter. Meanwhile, the pilot and main flames become less separated. Moreover, the flame in the outer shear layer (OSL) is extinguished, which is the key to suppressing the thermoacoustic instability. The flame with lower ASR exhibits large-scale periodic axial motion of flame dynamics. The flow fields of ASR = 15% (unstable) and ASR = 30% (stable) are analyzed and discussed to help reveal the differences in thermoacoustic instability between the two cases. It is found that the primary recirculation zone is smaller with ASR = 30%. Higher vorticity and strain rate distributions found in the OSL are believed to quench the flame there. The present study illustrates that a higher air split ratio improves the thermoacoustic stability, which is helpful in designing LPM combustors.
|
|
| 285. |
- He, Chengliang, et al.
(författare)
-
Asymmetric electron acceptor enables highly luminescent organic solar cells with certified efficiency over 18%
- 2022
-
Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Enhancing the luminescence property without sacrificing the charge collection is one key to high-performance organic solar cells (OSCs), while limited by the severe non-radiative charge recombination. Here, we demonstrate efficient OSCs with high luminescence via the design and synthesis of an asymmetric non-fullerene acceptor, BO-5Cl. Blending BO-5Cl with the PM6 donor leads to a record-high electroluminescence external quantum efficiency of 0.1%, which results in a low non-radiative voltage loss of 0.178 eV and a power conversion efficiency (PCE) over 15%. Importantly, incorporating BO-5Cl as the third component into a widely-studied donor:acceptor (D:A) blend, PM6:BO-4Cl, allows device displaying a high certified PCE of 18.2%. Our joint experimental and theoretical studies unveil that more diverse D:A interfacial conformations formed by asymmetric acceptor induce optimized blend interfacial energetics, which contributes to the improved device performance via balancing charge generation and recombination. High-performance organic solar cells call for novel designs of acceptor molecules. Here, He et al. design and synthesize a non-fullerene acceptor with an asymmetric structure for diverse donor:acceptor interfacial conformations and report a certificated power conversion efficiency of 18.2%.
|
|
| 286. |
- He, Kan, et al.
(författare)
-
Assessment of LES, IDDES and RANS approaches for prediction of wakes behind notchback road vehicles
- 2021
-
Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 217
-
Tidskriftsartikel (refereegranskat)abstract
- The capability of Large Eddy Simulations (LES), Improved Delayed Detached Eddy Simulations (IDDES) and Reynolds-Averaged Navier–Stokes Equations (RANS) to predict the flow behind notchback Ahmed body is investigated in the present paper. Simulations consider two specific models, with effective backlight angles of β1=17.8° and β2=21.0°, respectively. The focus of the study is on the prediction of the expected lateral asymmetry or symmetry of the near-wake flows. Results show that IDDES using coarse computational grids predicts the flow in agreement with LES using finer computational grids. RANS results in inaccurate flow predictions, attributed to its steady formulation relying on turbulence modelling being incapable of dealing with the studied flow. Modal analysis applying Proper Orthogonal Decomposition (POD) suggests the consistency of the wake dynamics between IDDES and LES. The presence of the wake bi-stability is validated by the wind tunnel experiment.
|
|
| 287. |
- He, Kan, 1991, et al.
(författare)
-
Blockage influence on bi-stable flows of a notchback bluff body
- 2021
-
Ingår i: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 33:12
-
Tidskriftsartikel (refereegranskat)abstract
- The expected flow asymmetry behind a three-dimensional notchback Ahmed body is numerically investigated using large-eddy simulations with different blockage ratios of 0%, 5 %, 10 %, and 20 %. The focus of the study is on the natural bi-stable flow influenced by the blockage ratio. Although the wake asymmetry can be observed under the blockage ratio within 0 % - 10 %, the significant blockage influence on the sensitive bi-stability is indicated by the wake structures, pressure gradients, and wake dynamics achieved with the proper orthogonal decomposition. The higher blockage ratio increases the turbulence kinetic energy, velocity, and negative pressure in the near-wake region, resulting in the decrease in the asymmetry degree. The consistency of the asymmetric wake is found with blockage ratios between 0% and 5 %. However, a 20 % blockage ratio symmetrizes the bi-stable wake. Several existing drag corrections for the blockage influence are discussed. The wind tunnel experiment verifies the bi-stable flow with low blockage ratios and the wake symmetrization with a 20 % blockage ratio.
|
|
| 288. |
- He, Kan, et al.
(författare)
-
Evaluation of LES, IDDES and URANS for prediction of flow around a streamlined high-speed train
- 2022
-
Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 223
-
Tidskriftsartikel (refereegranskat)abstract
- The turbulent flow past a simplified Intercity-Express 3 high-speed train at ReH=6×104 is investigated by a combination of wind tunnel experiments and numerical simulations using the large-eddy simulation (LES), the improved delayed detached eddy simulation (IDDES) and the unsteady Reynolds-averaged Navier-Stokes (URANS) simulation. This work aims to compare the predictive capabilities of LES, IDDES and URANS for the flow over a streamlined high-speed train. Numerical simulations are compared to experimental data for validation. Results show that the well-resolved LES is more accurate among the numerical methods used. Compared to the well-resolved LES, IDDES and URANS using the coarser mesh can produce similar mean flow, although IDDES and URANS are found to be slightly inaccurate for the coherent wake structures near the wall. However, for the near-wall flow instability concerning wake dynamics, Reynolds stresses, turbulence kinetic energy and the fluctuation of pressure, IDDES is found to be inapplicable. Overall, this study suggests that the well-resolved LES is appropriate to the flow of a streamlined high-speed train. Moreover, IDDES and URANS are proved to apply to the mean field of the studied flow.
|
|
| 289. |
- He, Kan, 1991, et al.
(författare)
-
Floor motion's influence on wake asymmetry of a notchback bluff body
- 2022
-
Ingår i: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 34:3
-
Tidskriftsartikel (refereegranskat)abstract
- Large eddy simulations are used to explore the influence of floor motions on asymmetric flows around a notchback bluff body. The focus of this study is on the aerodynamic forces and the extent of natural wake asymmetry presented under moving and stationary ground conditions. The different ground condition has a notable influence on the aerodynamic force and the surrounding pressure distribution of the body. On the other hand, the wake asymmetry, known to be a sensitive phenomenon, is not evidently affected by the floor motion. However, quantitative analysis of the averaged and the statistic flow still suggests slight differences in the degree of wake asymmetry between the two ground conditions. Modal analysis applying proper orthogonal decomposition confirms that the asymmetric wake dynamics and the wake shedding frequency are not sensitive to the floor motion. The accuracy of the numerical simulation is established by a grid-independence study.
|
|
| 290. |
- He, Kan, et al.
(författare)
-
Influence of the rounded rear edge on wake bi-stability of a notchback bluff body
- 2021
-
Ingår i: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 33:11
-
Tidskriftsartikel (refereegranskat)abstract
- The wake bi-stability behind notchback Ahmed bodies is investigated by performing wind tunnel experiments and large eddy simulations (LESs). The focus of this study is on the suppression of bi-stable wakes achieved by rounding the roof's trailing edge of the body. The suppression effect is found to depend on the Reynolds number (R e). The wake behind a sharp edge remains bi-stable for all tested R e. However, for a rounded edge with small radius, wake bi-stability at R e = 0.5 × 10 5 and wake symmetrization with 0.75 × 10 5 ≤ R e ≤ 1.5 × 10 5 are observed. Increasing R e with R e ≥ 1.75 × 10 5, the wake returns to the bi-stable state. Particularly, with R e ≥ 2 × 10 5, a stable asymmetric wake state with no switches is observed for long periods. Performing LES confirms the expected wake asymmetry at R e = 0.5 × 10 5 and symmetry at R e = 1 × 10 5 for the case of rounded edge with a small radius. Besides, another wake symmetry is observed for the rounded edge with a large radius at R e = 0.5 × 10 5. For the two wake symmetries shown in the LES results, the symmetrization is attributed to wake suppression in the notchback region, forcing the flow separation from the rear roof to attach to the slant on both sides of the body.
|
|
