Circular RNAs are a class of non-coding RNAs that are receiving extensive attention. Despite reports showing circular RNAs acting as microRNA sponges, the biological functions of circular RNAs remain ...largely unknown. We show that in patient tumor samples and in a panel of cancer cells, circ-Foxo3 was minimally expressed. Interestingly, during cancer cell apoptosis, the expression of circ-Foxo3 was found to be significantly increased. We found that silencing endogenous circ-Foxo3 enhanced cell viability, whereas ectopic expression of circ-Foxo3 triggered stress-induced apoptosis and inhibited the growth of tumor xenografts. Also, expression of circ-Foxo3 increased Foxo3 protein levels but repressed p53 levels. By binding to both, circ-Foxo3 promoted MDM2-induced p53 ubiquitination and subsequent degradation, resulting in an overall decrease of p53. With low binding affinity to Foxo3 protein, circ-Foxo3 prevented MDM2 from inducing Foxo3 ubiquitination and degradation, resulting in increased levels of Foxo3 protein. As a result, cell apoptosis was induced by upregulation of the Foxo3 downstream target PUMA.
With the increasing need to seamlessly integrate renewable energy with the current electricity grid, which itself is evolving into a more intelligent, efficient, and capable electrical power system, ...it is envisioned that energy‐storage systems will play a more prominent role in bridging the gap between current technology and a clean sustainable future in grid reliability and utilization. Redox flow battery technology is a leading approach in providing a well‐balanced solution for current challenges. Here, recent progress in the research and development of redox flow battery technology, including cell‐level components of electrolytes, electrodes, and membranes, is reviewed. The focus is on new redox chemistries for both aqueous and non‐aqueous systems.
With its unique configuration and mechanism, the redox flow battery technique is considered to be one of the most promising technologies for large‐scale stationary energy storage. Recent progress in the research and development of redox flow battery cell‐level components is highlighted, including electrolytes, electrodes, and membranes for both aqueous and non‐aqueous systems.
As an alternative to Nafion® ion exchange membrane, an inexpensive commercially-available Radel® polymer was sulfonated, fabricated into a thin membrane, and evaluated for its performance in a ...vanadium redox flow battery (VRFB). The sulfonated Radel (S-Radel) membrane showed almost an order of magnitude lower permeability of VO
2+ ions (2.07
×
10
−7
cm
2/min), compared to Nafion 117 (1.29
×
10
−6
cm
2/min), resulting in better coulombic efficiency (~
98% vs. 95% at 50
mA/cm
2) and lower capacity loss per cycle. Even though the S-Radel membrane had a slightly higher membrane resistance, the energy efficiency of the VRFB with the S-Radel membrane was comparable to that of Nafion because of its better coulombic efficiency resulting from the lower vanadium ion crossover. The S-Radel membrane exhibited good performance up to 40 cycles, but a decline in performance at later cycles was observed, likely as a result of membrane degradation.
Sulfonated Diels Alder poly(phenylene) (SDAPP) was examined for vanadium redox flow battery (VRFB) use. The ion exchange capacity (IEC) was varied from 1.4, 1.6 and 2.0meq/g in order to tune the ...proton conductivity and vanadium permeability. Coulombic efficiencies between 92 to 99% were observed, depending on IEC (lower IEC, higher coulombic efficiencies). In all cases the SDAPP displayed comparable energy efficiencies (88–90%) to Nafion 117 (88%) at 50mA/cm2. Membrane durability also was dependent on IEC; SDAPP with the highest IEC lasted slightly over 50cycles while SDAPP with the lowest IEC lasted over 400cycles and testing was discontinued only due to time constraints. Durability screening tests were initialed with SDAPP, by soaking films in a 0.1MV5+ and 5.0M total SO4−2 solution. The rate of degradation was also proportional with IEC; the 2meq/g sample dissolved within 376h, the 1.6meq/g sample dissolved after 860h, while the 1.4meq/g sample broke apart after 1527h.
As central nodes in cardiomyocyte signaling, nuclear AKT appears to play a cardio-protective role in cardiovascular disease. Here we describe a circular RNA, circ-Amotl1 that is highly expressed in ...neonatal human cardiac tissue, and potentiates AKT-enhanced cardiomyocyte survival. We hypothesize that circ-Amotl1 binds to PDK1 and AKT1, leading to AKT1 phosphorylation and nuclear translocation. In primary cardiomyocytes, epithelial cells, and endothelial cells, we found that forced circ-Amotl1 expression increased the nuclear fraction of pAKT. We further detected increased nuclear pAKT in circ-Amotl1-treated hearts. In vivo, circ-Amotl1 expression was also found to be protective against Doxorubicin (Dox)-induced cardiomyopathy. Putative PDK1- and AKT1-binding sites were then identified
. Blocking oligonucleotides could reverse the effects of exogenous circ-Amotl1. We conclude that circ-Amotl1 physically binds to both PDK1 and AKT1, facilitating the cardio-protective nuclear translocation of pAKT.
The increasing penetration of renewable energy and the trend toward clean, efficient transportation have spurred growing interests in sodium-beta alumina batteries that store electrical energy via ...sodium ion transport across a β″-Al
2O
3 solid electrolyte at elevated temperatures (typically 300–350
°C). Currently, the negative electrode or anode is metallic sodium in molten state during battery operation; the positive electrode or cathode can be molten sulfur (Na–S battery) or solid transition metal halides plus a liquid phase secondary electrolyte (e.g., ZEBRA battery). Since the groundbreaking works in the sodium-beta alumina batteries a few decades ago, encouraging progress has been achieved in improving battery performance, along with cost reduction. However, there remain issues that hinder broad applications and market penetration of the technologies. To better the Na-beta alumina technologies require further advancement in materials along with component and system design and engineering. This paper offers a comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement.
A functionalized graphene sheet-sulfur (FGSS) nanocomposite was synthesized as the cathode material for lithium-sulfur batteries. The structure has a layer of functionalized graphene sheets/stacks ...(FGS) and a layer of sulfur nanoparticles creating a three-dimensional sandwich-type architecture. This unique FGSS nanoscale layered composite has a high loading (70 wt%) of active material (S), a high tap density of ∼0.92 g cm(-3), and a reversible capacity of ∼505 mAh g(-1) (∼464 mAh cm(-3)) at a current density of 1680 mA g(-1) (1C). When coated with a thin layer of cation exchange Nafion film, the migration of dissolved polysulfide anions from the FGSS nanocomposite was effectively reduced, leading to a good cycling stability of 75% capacity retention over 100 cycles. This sandwich-structured composite conceptually provides a new strategy for designing electrodes in energy storage applications.
Large‐scale electrical energy storage has become more important than ever for reducing fossil energy consumption in transportation and for the widespread deployment of intermittent renewable energy ...in electric grid. However, significant challenges exist for its applications. Here, the status and challenges are reviewed from the perspective of materials science and materials chemistry in electrochemical energy storage technologies, such as Li‐ion batteries, sodium (sulfur and metal halide) batteries, Pb‐acid battery, redox flow batteries, and supercapacitors. Perspectives and approaches are introduced for emerging battery designs and new chemistry combinations to reduce the cost of energy storage devices.
The different applications of energy storage, different technologies, and the cost requirements from the kilowatt to gigawatt scale are compared. Li‐ion batteries have attracted attention for transportation storage, while many other technologies are considered for stationary applications.
The all‐vanadium redox flow battery is a promising technology for large‐scale renewable and grid energy storage, but is limited by the low energy density and poor stability of the vanadium ...electrolyte solutions. A new vanadium redox flow battery with a significant improvement over the current technology is reported in this paper. This battery uses sulfate‐chloride mixed electrolytes, which are capable of dissolving 2.5 M vanadium, representing about a 70% increase in energy capacity over the current sulfate system. More importantly, the new electrolyte remains stable over a wide temperature range of −5 to 50 °C, potentially eliminating the need for electrolyte temperature control in practical applications. This development would lead to a significant reduction in the cost of energy storage, thus accelerating its market penetration.
A new vanadium redox flow battery has been developed. This battery uses sulfate‐chloride mixed electrolytes, which are capable of dissolving 2.5 M vanadium, representing about a 70% increase in energy capacity over the current sulfate system. More importantly, the new electrolyte remains stable over a wide temperature range of −5 to 50 °C, potentially eliminating the need for electrolyte temperature control in practical applications.
We demonstrate an excellent performance of nitrogen-doped mesoporous carbon (N-MPC) for energy storage in vanadium redox flow batteries. Mesoporous carbon (MPC) is prepared using a soft-template ...method and doped with nitrogen by heat-treating MPC in NH
3. N-MPC is characterized with X-ray photoelectron spectroscopy and transmission electron microscopy. The redox reaction of VO
2+/VO
2
+ is characterized with cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic kinetics of the redox couple VO
2+/VO
2
+ is significantly enhanced on N-MPC electrode compared with MPC and graphite electrodes. The reversibility of the redox couple VO
2+/VO
2
+ is greatly improved on N-MPC (0.61 for N-MPC vs. 0.34 for graphite), which is expected to increase the energy storage efficiency of redox flow batteries. Nitrogen doping facilitates the electron transfer on electrode/electrolyte interface for both oxidation and reduction processes. N-MPC is a promising material for redox flow batteries. This also opens up new and wider applications of nitrogen-doped carbon.
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