Modifying the crystal structure and corresponding functional properties of complex oxides by regulating their oxygen content has promising applications in energy conversion and chemical looping, ...where controlling oxygen migration plays an important role. Therefore, finding an efficacious and feasible method to facilitate oxygen migration has become a critical requirement for practical applications. Here, we report a compressive-strain-facilitated oxygen migration with reversible topotactic phase transformation (RTPT) in La0.5Sr0.5CoO x films based on all-solid-state electrolyte gating modulation. With the lattice strain changing from tensile to compressive strain, significant reductions in modulation duration (∼72%) and threshold voltage (∼70%) for the RTPT were observed, indicating great promotion of RTPT by compressive strain. Density functional theory calculations verify that such compressive-strain-facilitated efficient RTPT comes from significant reduction of the oxygen migration barrier in compressive-strained films. Further, ac-STEM, EELS, and sXAS investigations reveal that varying strain from tensile to compressive enhances the Co 3d band filling, thereby suppressing the Co–O hybrid bond in oxygen vacancy channels, elucidating the micro-origin of such compressive-strain-facilitated oxygen migration. Our work suggests that controlling electronic orbital occupation of Co ions in oxygen vacancy channels may help facilitate oxygen migration, providing valuable insights and practical guidance for achieving highly efficient oxygen-migration-related chemical looping and energy conversion with complex oxides.
The synthesis of well-defined light-element-derived quantum dots (LEQDs) with advanced optical properties under mild conditions is highly desirable yet challenging. Here, a polyaniline (PANI) ...structure is introduced into carbon-rich LEQDs to yield well-defined, fluorescent polyaniline quantum dots (PAQDs), PAQD24, through a one-pot room temperature reaction. The mild synthetic conditions effectively minimize the defects introduced during the conventional synthesis and endow PAQD24 with desirable optical properties, including a narrow emission band (full width at half maximum = 55 nm), an optimal quantum yield of 32.5% and two-photon fluorescence. Furthermore, the bandgap of PAQD24 is highly sensitive toward pH variations in the near-neutral region, due to the proton doping and dedoping of the PANI structure. Such unique properties together with its fine bio-compatibility enable the application of this material as a turn-on fluorescent probe for the labeling of acidic biotargets from sub-cellular to organ levels, providing potential applications in diagnosis and surgery guidance for certain diseases.
pH-Switchable organic quantum dots based on a polyaniline scaffold are suitable for the labeling of acidic biotargets.
MicroRNAs (miRNAs) play crucial roles in the development of essential hypertension (EH). Previously, we found that the expression of miR-1929-3p was decreased in C57BL/6 mice with hypertension ...induced by murine cytomegalovirus (MCMV). In this study, we explored the role of miR-1929-3p in hypertension myocardial remodeling in MCMV-infected mice. First, we measured MCMV DNA and host IgG and IgM after infection and determined the expression of miR-1929-3p and its target gene endothelin A receptor (Ednra) mRNA in the myocardium of mice. Then, we performed invasive blood pressure (BP) monitoring. Heart-to-body weight ratio (HW/BW%), along with mRNA levels of B-type natriuretic peptide (BNP) and beta myosin heavy chain (β-MHC), revealed myocardial remodeling. Hematoxylin/eosin and Masson’s trichrome staining indicated morphological changes in the myocardium. Cardiac function was assessed via echocardiography. Moreover, MCMV-infected mice were injected with recombinant adeno-associated virus- (rAAV-) miR-1929-3p overexpression vector. Immunohistochemistry and western blotting showed the expression of Ednra and the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome. And enzyme-linked immunosorbent assay (ELISA) revealed the concentrations of endothelin-1 (ET-1), interleukin-1β (IL-1β), and interleukin-18 (IL-18). In this study, we found that decreased expression of miR-1929-3p in MCMV-infected mice induced high BP and further development of myocardial remodeling cardiac function injury through increased expression of Ednra. Strikingly, overexpression of miR-1929-3p ameliorated these pathological changes of the heart. The positive effect was shown to be associated with inhibition of NLRP3 inflammasome activation and decreased expression of key proinflammatory cytokine IL-1β. Collectively, these results indicate that miR-1929-3p overexpression may effectively alleviate EH myocardial remodeling by suppressing Ednra/NLRP3 inflammasome activation in MCMV-infected mice.
Heart transplantation has been applied in the clinic as an optimal solution for patients with end stage cardiac failure for a number of years. However, hypothermic preservation of the heart remains ...limited to 4-6 h and calcium accumulation over time is an important factor resulting in cell death. To provide longer and safer storage for donor hearts, it was demonstrated in our previous study that luteolin, a traditional Chinese medicine used to treat cardiovascular diseases, inhibits cell death and L-type calcium currents during hypothermic preservation. In the current study, the protective role of luteolin in modulating cardiomyocyte calcium cycling was further investigated. Intracellular calcium overload has already been implicated in hypothermia-induced dysfunction of cardiomyocytes. University of Wisconsin (UW) solution supplemented with 7.5, 15 or 30 µmol/l luteolin was used to preserve fresh isolated cardiomyocytes at 4°C. The results demonstrated that all three doses of luteolin supplementation attenuated calcium overload over a 6 h preservation period. Luteolin also suppressed the accumulation of important regulatory proteins and enzymes for cardiomyocyte calcium circulation, mitochondria Ca
uniporter and calmodulin, which are normally induced by cold storage in UW solution. Protein Kinase A activity was also suppressed in cardiomyocytes preserved in luteolin supplemented UW solution, while Ca
-Mg
-ATPase activity was increased. The results demonstrated that luteolin confers a cardioprotective effect through inhibiting the changes of calcium regulators during cold storage and therefore ameliorates Ca
overload in rat cardiomyocytes.
Long-term scheduling for cascaded hydro energy systems is very important for low carbon energy production. It aims at determining the water release over a planning horizon to meet water resource ...requirements and the system demands for electric power. The problem is challenging in view of the complicated and stochastic system dynamics, nonlinear marginal cost, coupled hydraulic constraints, and the large problem size. In this paper we formulate the long-term scheduling problem of cascaded hydro energy systems with annual consumption and release constraints as a finite horizon constrained Markov decision process (CMDP), and develop a new rollout algorithm to optimize the policies. Numerical results demonstrate the effectiveness and the efficiency of the formulation and the new algorithm.
The current study aimed to evaluate whether luteolin could improve long-term heart preservation; this was achieved by evaluating the heart following long-term storage in University of Wisconsin ...solution (the control group) and in solutions containing three luteolin concentrations. The effects of different preservation methods were evaluated with respect to cardiac function while hearts were in custom-made
Langendorff perfusion systems. Different preservation methods were evaluated with respect to the histology, ultrastructure and apoptosis rate of the hearts, and the function of cardiomyocytes. In the presence of luteolin, the rate pressure product of the left ventricle was increased within 60 min of reperfusion following a 12-h preservation, coronary flow was higher within 30 min of reperfusion, cardiac contractile function was higher throughout reperfusion following 12- and 18-h preservations, and the left ventricle peak systolic pressure was significantly higher compared with the control group (all P<0.05). The expression levels of apoptosis regulator Bax and apoptosis regulator Bcl-2 in the luteolin groups were significantly decreased and increased, respectively. Lactate dehydrogenase, creatine kinase and malondialdehyde enzymatic activity was increased following long-term storage, while the activity of superoxide dismutase was significantly decreased. Furthermore, luteolin inhibited L-type calcium currents in ventricular myocytes under hypoxia conditions. Thus, luteolin demonstrated protective effects during long-term heart preservation in what appeared to be a dose-dependent manner, which may be accomplished through inhibiting hypoxia-dependent L-type calcium channels.
Based on the physically characterized distributed hydrological modeling scheme – WEP-L – a more generalized and expandable method – AutoWEP – has been developed that is equipped with updated modules ...for pre-processing and automatic parameter identification. Sub-basin scale classifications of land use and soil are undertaken by incorporating remote sensing data and geographic information system techniques. In the process of developing the AutoWEP modeling scheme, a new concept of parameter partitioning is proposed and an automatic delineation of parameter partitions is achieved through programming. The sensitivity analysis algorithm, LH-OAT, and the parameter optimization algorithm, SCE-UA, are embedded in the model. Its application to the upstream watershed of the Miyun Reservoir shows that AutoWEP features time-savings, improved efficiency and suitable generalizations, that result in a long series of acceptable simulations.
Semi-solid powder rolling (SSPR) is a novel strip manufacturing process, which combines powder rolling with semi-solid rolling in one step. Based on the features of SSPR, powders were heated to the ...semi-solid temperature range and then rolled. Therefore, oxides will form during heating and rolling. The oxidation behavior of 7050 aluminum during SSPR was analyzed and the quantity, distribution and morphology of oxides are discussed. The effects of quantity, distribution and morphology of the oxides on the microhardness of strips under different conditions were studied. The results showed that the main factor influencing the quantity of oxides is the heating temperature. The mechanism of oxidation during SSPR was found to be diffusion controlled. In the heating stage, surface oxide films hinder the diffusion. In the rolling stage, surface oxide layers were broken and so the oxidation of aluminum alloy mainly took place in the rolling stage. The formed oxides are Al
2
O
3
with a little of MgO showing an irregular morphology with a size of 2–3 µm. High bonding quality between the oxide particles and the matrix, as well as an uniform distribution of the oxides, leads to a higher microhardness of the SSPR-ed strips. But, the bonding quality between the oxide particles and the matrix is poor under conditions of low liquid fraction and some oxides distribute non-uniformly around the grain boundaries.
PDF
