There are great challenges in developing efficient adsorbents to replace the currently used and energy-intensive cryogenic distillation processes for olefin/paraffin separation, owing to the similar ...physical properties of the two molecules. Here we report an ultramicroporous metal-organic framework Ca(C
O
)(H
O), synthesized from calcium nitrate and squaric acid, that possesses rigid one-dimensional channels. These apertures are of a similar size to ethylene molecules, but owing to the size, shape and rigidity of the pores, act as molecular sieves to prevent the transport of ethane. The efficiency of this molecular sieve for the separation of ethylene/ethane mixtures is validated by breakthrough experiments with high ethylene productivity under ambient conditions. This material can be easily synthesized at the kilogram scale using an environmentally friendly method and is water-stable, which is important for potential industrial implementation. The strategy of using highly rigid metal-organic frameworks with well defined and rigid pores could also be extended to other porous materials for chemical separation processes.
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IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
Mitochondrial damage is a critical contributor to cardiac ischemia/reperfusion (I/R) injury. Mitochondrial quality control (MQC) mechanisms, a series of adaptive responses that preserve mitochondrial ...structure and function, ensure cardiomyocyte survival and cardiac function after I/R injury. MQC includes mitochondrial fission, mitochondrial fusion, mitophagy and mitochondria-dependent cell death. The interplay among these responses is linked to pathological changes such as redox imbalance, calcium overload, energy metabolism disorder, signal transduction arrest, the mitochondrial unfolded protein response and endoplasmic reticulum stress. Excessive mitochondrial fission is an early marker of mitochondrial damage and cardiomyocyte death. Reduced mitochondrial fusion has been observed in stressed cardiomyocytes and correlates with mitochondrial dysfunction and cardiac depression. Mitophagy allows autophagosomes to selectively degrade poorly structured mitochondria, thus maintaining mitochondrial network fitness. Nevertheless, abnormal mitophagy is maladaptive and has been linked to cell death. Although mitochondria serve as the fuel source of the heart by continuously producing adenosine triphosphate, they also stimulate cardiomyocyte death by inducing apoptosis or necroptosis in the reperfused myocardium. Therefore, defects in MQC may determine the fate of cardiomyocytes. In this review, we summarize the regulatory mechanisms and pathological effects of MQC in myocardial I/R injury, highlighting potential targets for the clinical management of reperfusion.
Mitochondrial quality control contributes to acute cardiac I/R injury. The mitochondrial network is constantly reshaped by the antagonistic activities between mitochondrial fission and fusion. Mitophagy allows autophagosomes to selectively degrade damaged mitochondria. When these adaptive responses fail, programmed cell death by apoptosis or necroptosis is activated. Display omitted
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper presents a content-centric transmission design in a cloud radio access network by incorporating multicasting and caching. Users requesting the same content form a multicast group and are ...served by a same cluster of base stations (BSs) cooperatively. Each BS has a local cache, and it acquires the requested contents either from its local cache or from the central processor via backhaul links. We investigate the dynamic content-centric BS clustering and multicast beamforming with respect to both channel condition and caching status. We first formulate a mixed-integer nonlinear programming problem of minimizing the weighted sum of backhaul cost and transmit power under the quality-of-service constraint for each multicast group. Theoretical analysis reveals that all the BSs caching a requested content can be included in the BS cluster of this content, regardless of the channel conditions. Then, we reformulate an equivalent sparse multicast beamforming (SBF) problem. By adopting smoothed ℓ 0 -norm approximation and other techniques, the SBF problem is transformed into the difference of convex programs and effectively solved using the convex-concave procedure algorithms. Simulation results demonstrate significant advantage of the proposed content-centric transmission. The effects of heuristic caching strategies are also evaluated.
Tetracycline (TC) is one of the most widely used antibiotics with significant impacts on human health and thus it needs appropriate approaches for its removal. In the present study, we evaluated the ...performance and complete pathway of the TC electrochemical oxidation on a Ti/Ti4O7 anode prepared by plasma spraying. Morphological data and composition analysis indicated a compact coating layer on the anode, which had the characteristic peaks of Ti4O7 as active constituent. The TC electrochemical oxidation on the Ti/Ti4O7 anode followed a pseudo-first-order kinetics, and the TC removal efficiency reached 95.8% in 40 min. The influential factors on TC decay kinetics included current density, anode-cathode distance and initial TC concentration. This anode also had high durability and the TC removal efficiency was maintained over 95% after five times reuse. For the first time, we unraveled the complete pathway of the TC electrochemical oxidation using high-performance liquid chromatograph (HPLC) and gas chromatograph (GC) coupled with mass spectrometer (MS). ·OH radicals produced from electrochemical oxidation attack the double bond, phenolic group and amine group of TC, forming a primary intermediate (m/z = 461), secondary intermediates (m/z = 432, 477 and 509) and tertiary intermediates (m/z = 480, 448 and 525). The latter were further oxidized to the key downstream intermediate (m/z = 496), followed by further downstream intermediates (m/z = 451, 412, 396, 367, 351, 298 and 253) and eventually short-chain carboxylic acids. We also evaluated the toxicity change during the electrochemical oxidation process with bioluminescent bacteria. The bioluminescence inhibition ratio peaked at 10 min (55.41%), likely owing to the high toxicity of intermediates with m/z = 461, 432 and 477 as obtained from quantitative structure activity relationship (QSAR) analysis. The bioluminescence inhibition ratio eventually decreased to 16.78% in 40 min due to further transformation of TC and intermediates. By comprehensively analyzing the influential factors and complete degradation pathway of TC electrochemical oxidation on the Ti/Ti4O7 anode, our research provides deeper insights into the risk assessment of intermediates and their toxicity, assigning new perspectives for practical electrochemical oxidation to effectively eliminate the amount and toxicity of TC and other antibiotics in wastewater.
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•Satisfactory tetracycline degradation (95.8%) on a Ti/Ti4O7 anode.•The tetracycline electrochemical oxidation follows a pseudo-first order kinetics.•First complete pathway of tetracycline electrochemical oxidation.•Toxicity evaluation of 25 intermediates by QSAR explains toxicity reduction delay.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Mitochondrial quality surveillance is regulated by a variety of adaptive responses.•Mitochondrial fission favors the elimination of depolarized mitochondria through mitophagy.•The double-edge sword ...of mitophagy needs to be taken into consideration in the conception of new pharmacological approaches to treat MI.•Mitochondrial biogenesis represents a regenerative program to replace old and damaged mitochondria with new and healthy ones.•Mitochondrial bioenergetics is regulated by a metabolic switch between glucose and fatty acid usage, depending on oxygen availability.
Myocardial infarction (MI) is the irreversible death of cardiomyocyte secondary to prolonged lack of oxygen or fresh blood supply. Historically considered as merely cardiomyocyte powerhouse that manufactures ATP and other metabolites, mitochondrion is recently being identified as a signal regulator that is implicated in the crosstalk and signal integration of cardiomyocyte contraction, metabolism, inflammation, and death. Mitochondria quality surveillance is an integrated network system modifying mitochondrial structure and function through the coordination of various processes including mitochondrial fission, fusion, biogenesis, bioenergetics, proteostasis, and degradation via mitophagy. Mitochondrial fission favors the elimination of depolarized mitochondria through mitophagy, whereas mitochondrial fusion preserves the mitochondrial network upon stress through integration of two or more small mitochondria into an interconnected phenotype. Mitochondrial biogenesis represents a regenerative program to replace old and damaged mitochondria with new and healthy ones. Mitochondrial bioenergetics is regulated by a metabolic switch between glucose and fatty acid usage, depending on oxygen availability. To maintain the diversity and function of mitochondrial proteins, a specialized protein quality control machinery regulates protein dynamics and function through the activity of chaperones and proteases, and induction of the mitochondrial unfolded protein response. In this review, we provide an overview of the molecular mechanisms governing mitochondrial quality surveillance and highlight the most recent preclinical and clinical therapeutic approaches to restore mitochondrial fitness during both MI and post-MI heart failure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•We propose an improved neural network model to predict the stock prices.•The empirical mode decomposition and factorization machine are used in our approach.•The empirical mode decomposition helps ...overcome the non-stationarity of stock price.•Factorization Machine helps grasp the nonlinear interactions among the inputs.•The real data sets are used to demonstrate the accuracy of the new approach.
Stock market forecasting is a vital component of financial systems. However, the stock prices are highly noisy and non-stationary due to the fact that stock markets are affected by a variety of factors. Predicting stock market trend is usually subject to big challenges. The goal of this paper is to introduce a new hybrid, end-to-end approach containing two stages, the Empirical Mode Decomposition and Factorization Machine based Neural Network (EMD2FNN), to predict the stock market trend. To illustrate the method, we apply EMD2FNN to predict the daily closing prices from the Shanghai Stock Exchange Composite (SSEC) index, the National Association of Securities Dealers Automated Quotations (NASDAQ) index and the Standard & Poor’s 500 Composite Stock Price Index (S&P 500), which respectively exhibit oscillatory, upward and downward patterns. The results are compared with predictions obtained by other methods, including the neural network (NN) model, the factorization machine based neural network (FNN) model, the empirical mode decomposition based neural network (EMD2NN) model and the wavelet de-noising-based back propagation (WDBP) neural network model. Under the same conditions, the experiments indicate that the proposed methods perform better than the other ones according to the metrics of Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE). Furthermore, we compute the profitability with a simple long-short trading strategy to examine the trading performance of our models in the metrics of Average Annual Return (AAR), Maximum Drawdown (MD), Sharpe Ratio (SR) and AAR/MD. The performances in two different scenarios, when taking or not taking the transaction cost into consideration, are found economically significant.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
With the rapid development of biomimetic asymmetric reduction, the demand for efficient chiral and regenerable NAD(P)H models is growing rapidly. Herein, a new class of 2.2paracyclophane-based chiral ...and regenerable NAD(P)H models (CYNAMs) was designed and synthesized. The first enantioselective biomimetic reduction of tetrasubstituted alkene flavonoids has been successfully realized through enzyme-like cooperative bifunctional activation, giving chiral flavanones with up to 99% yield and 99% ee.
With the rapid development of biomimetic asymmetric reduction, the demand for efficient chiral and regenerable NAD(P)H models is growing rapidly.
The development of biomimetic chemistry based on the NAD(P)H with hydrogen gas as terminal reductant is a long‐standing challenge. Through rational design of the chiral and regenerable NAD(P)H ...analogues based on planar‐chiral ferrocene, a biomimetic asymmetric reduction has been realized using bench‐stable Lewis acids as transfer catalysts. A broad set of alkenes and imines could be reduced with up to 98 % yield and 98 % ee, likely enabled by enzyme‐like cooperative bifunctional activation. This reaction represents the first general biomimetic asymmetric reduction (BMAR) process enabled by chiral and regenerable NAD(P)H analogues. This concept demonstrates catalytic utility of a chiral coenzyme NAD(P)H in asymmetric catalysis.
Through rational design of chiral and regenerable NAD(P)H analogues based on planar‐chiral ferrocene, a biomimetic asymmetric reduction has been realized using bench‐stable Lewis acids as transfer catalysts. A broad set of tetrasubstituted alkenes and imines could be reduced with up to 98 % yield and 98 % ee. This protocol represents the first general biomimetic asymmetric reduction process enabled by NAD(P)H analogues.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Solar prominences are subject to all kinds of perturbations during their lifetime, and frequently demonstrate oscillations. The study of prominence oscillations provides an alternative way to ...investigate their internal magnetic and thermal structures because the characteristics of the oscillations depend on their interplay with the solar corona. Prominence oscillations can be classified into longitudinal and transverse types. We perform three-dimensional ideal magnetohydrodynamic simulations of prominence oscillations along a magnetic flux rope, with the aim of comparing the oscillation periods with those predicted by various simplified models and examining the restoring force. We find that the longitudinal oscillation has a period of about 49 minutes, which is in accordance with the pendulum model where the field-aligned component of gravity serves as the restoring force. In contrast, the horizontal transverse oscillation has a period of about 10 minutes and the vertical transverse oscillation has a period of about 14 minutes, and both of them can be nicely fitted with a two-dimensional slab model. We also find that the magnetic tension force dominates most of the time in transverse oscillations, except for the first minute when magnetic pressure overwhelms it.
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