Internal Flow Research and Fluid-Solid Coupling Analysis for Bulb Turbine with Considering Gravity Affect and Non-uniform Inflow

International audienceLow head bulb turbine has lower hub-tip ratio and higher flow capacity, the characteristics of easy deformation of the cantilever blades under the heavier loads, and the horizontal arrangement which adopted in bulb turbine. Therefore, the water gravity has a significant influence on the internal flow of the turbine. In order to explore the influence of gravity and non-uniform inflow which on the hydrodynamic characteristic and external characteristic of the bulb turbine, this paper has conducted a CFD simulation of a bulb turbine with the fluid-solid coupling method under the boundary condition which considering the free surface and gravity, and analyzed the changes of structural stress and strain under non-uniform inflow and gravity field conditions. The results show that the flow field becomes more complicated due to the vertical pressure gradient caused by gravity. The locality and periodicity of cavitation which occurred in the runner is obvious. And the alternating water pressure were acting on the blades when the runner during the rotating. And the axis symmetry went worse because of the influence of free surface, mutation of the flow passage and water gravity. With the rotation of the runner, blades which under the different circumferential positions were bearing the alternating stress. Also, the maximum deformation at the blade rim position varied in different circumferential positions. This phenomenon is not good for the safe operation of the units

Selective depletion of a CD64-expressing phagocyte subset mediates protection against toxic kidney injury and failure

Dendritic cells (DC), macrophages, and monocytes, collectively known as mononuclear phagocytes (MPs), critically control tissue homeostasis and immune defense. However, there is a paucity of models allowing to selectively manipulate subsets of these cells in specific tissues. The steady-state adult kidney contains four MP subsets with Clec9a-expression history that include the main conventional DC1 (cDC1) and cDC2 subtypes as well as two subsets marked by CD64 but varying levels of F4/80. How each of these MP subsets contributes to the different phases of acute kidney injury and repair is unknown. We created a mouse model with a Cre-inducible lox-STOP-lox-diphtheria toxin receptor cassette under control of the endogenous CD64 locus that allows for diphtheria toxin–mediated depletion of CD64-expressing MPs without affecting cDC1, cDC2, or other leukocytes in the kidney. Combined with specific depletion of cDC1 and cDC2, we revisited the role of MPs in cisplatin-induced kidney injury. We found that the intrinsic potency reported for CD11c$^{+}$cells to limit cisplatin toxicity is specifically attributed to CD64$^{+}$MPs, while cDC1 and cDC2 were dispensable. Thus, we report a mouse model allowing for selective depletion of a specific subset of renal MPs. Our findings in cisplatin-induced injury underscore the value of dissecting the functions of individual MP subsets in kidney disease, which may enable therapeutic targeting of specific immune components in the absence of general immunosuppression

Mesenchymal stem cell exosomes reverse acute lung injury through Nrf-2/ARE and NF-κB signaling pathways

Acute lung injury (ALI) is associated with histopathological diffuse alveolar damage. The potential role of mesenchymal stem cells (MSCs) in the treatment of various clinical disorders have been widely documented, such as those for ALI. Recent evidence has demonstrated that exosomes from endothelial progenitor cells can improve outcomes of the lipopolysaccharide (LPS)-induced ALI. However, there has been no research on the potential role of MSC-exosomes in the treatment of sepsis-induced ALI, which is worth further exploration. Thus, the objective of our study was to identify whether the MSC-exosomes could reverse ALI. The ALI model induced by LPS was established in this study. MTT assay was performed to test cell proliferation. Expression of inflammatory factors (TNF-α, IL-6, and IL-10) in the LPS-treated type II alveolar epithelial cells (AECs) (MLE-12) was detected by ELISA. After co-culture of MSC-exosomes with LPS-treated MLE-12 cells, we found that the cell proliferation of MLE-12 cells gradually increased. Furthermore, we selected five of the Nrf-2/ARE- and NF-κB signaling pathway-related genes to explore if MSC-exosomes could reverse LPS-induced ALI through Nrf-2/ARE and NF-κB signaling pathways. QRT-PCR and western blot experiment results showed that the expression of these five genes were significantly regulated after stimulation with high-concentration LPS and exosome intervention. Taken together, these findings highlighted the fact that MSC-exosomes could reverse ALI through the Nrf-2/ARE and NF-κB signaling pathways. The MSC-exosome may be the potential future therapeutic strategy for the treatment of ALI

Ga₂O₃ Schottky Avalanche Solar-Blind Photodiode with High Responsivity and Photo-to-Dark Current Ratio

Solar-blind photodetectors have attracted extensive attention due to their advantages such as ultra-low background noise and all-weather. In this study, the planar Ti/Ga2O3/Au Schottky avalanche photodetector (APD) is fabricated based on β-Ga2O3 epitaxial film on the sapphire substrate grown by metal–organic chemical vapor deposition. The Schottky APD exhibits a high responsivity of 9780.23 A W−1, an ultrahigh photo-to-dark current ratio of 1.88 × 107, an external quantum efficiency of 4.77 × 106%, a specific detectivity of 9.48 × 1014 Jones, with an ultrahigh gain of 1 × 106 under 254 nm light illumination at 60 V reverse bias, indicating high application potential for solar-blind imaging. The superior photoresponse performances ascribe to the effective carrier avalanche multiplication, which contributes to the high photocurrent, and the high quality Schottky junction depletion, which leads to the low dark current.</p

Amorphous Ga₂O₃ Schottky photodiodes with high-responsivity and photo-to-dark current ratio

Schottky photodiodes with sputtered amorphous Ga2O3 (a-Ga2O3) and asymmetric electrodes were fabricated for the first time and achieved excellent performances under 254-nm light illumination with the superhigh responsivity of 1021.8 A W−1, high photo-to-dark current ratio of 2.3 × 106, fast rise/decay response time of 144/208 ms, high detectivity of 1.66 × 1016 Jones, and high external quantum efficiency of 5.0 × 105 %. The excellent solar-blind detection performances are suggested to be attribute to the large concentration of oxygen vacancies, the possible photo released carriers from the deep-level acceptors, and the high film uniformity, while the former two contribute to the high photo carrier concentration, and the latter one contributes to high quality Schottky contact to achieve the low dark current. A 10 × 10 array based on these a-Ga2O3 Schottky photodiodes realized the imaging of a “E” character with high contrast. The results give a feasible way to achieve large area, low cost, high contrast, and high detection sensitivity solar-blind imaging.</p

Interleukin-10 enhances recruitment of immune cells in the neonatal mouse model of obstructive nephropathy

Abstract Urinary tract obstruction during renal development leads to inflammation, leukocyte infiltration, tubular cell death, and interstitial fibrosis. Interleukin-10 (IL-10) is an anti-inflammatory cytokine, produced mainly by monocytes/macrophages and regulatory T-cells. IL-10 inhibits innate and adaptive immune responses. IL-10 has a protective role in the adult model of obstructive uropathy. However, its role in neonatal obstructive uropathy is still unclear which led us to study the role of IL-10 in neonatal mice with unilateral ureteral obstruction (UUO). UUO serves as a model for congenital obstructive nephropathies, a leading cause of kidney failure in children. Newborn Il-10 −/− and C57BL/6 wildtype-mice (WT) were subjected to complete UUO or sham-operation on the 2nd day of life. Neonatal kidneys were harvested at day 3, 7, and 14 of life and analyzed for different leukocyte subpopulations by FACS, for cytokines and chemokines by Luminex assay and ELISA, and for inflammation, programmed cell death, and fibrosis by immunohistochemistry and western blot. Compared to WT mice, Il-10 −/− mice showed reduced infiltration of neutrophils, CD11bhi cells, conventional type 1 dendritic cells, and T-cells following UUO. Il-10 −/− mice with UUO also showed a reduction in pro-inflammatory cytokine and chemokine release compared to WT with UUO, mainly of IP-10, IL-1α, MIP-2α and IL-17A. In addition, Il-10 −/− mice showed less necroptosis after UUO while the rate of apoptosis was not different. Finally, α-SMA and collagen abundance as readout for fibrosis were similar in Il-10 −/− and WT with UUO. Surprisingly and in contrast to adult Il-10 −/− mice undergoing UUO, neonatal Il-10 −/− mice with UUO showed a reduced inflammatory response compared to respective WT control mice with UUO. Notably, long term changes such as renal fibrosis were not different between neonatal Il-10 −/− and neonatal WT mice with UUO suggesting that IL-10 signaling is different in neonates and adults with UUO