Covalent organic frameworks (COFs) are promising for catalysis, sensing, gas storage, adsorption, optoelectricity, etc. owning to the unprecedented combination of large surface area, high ...crystallinity, tunable pore size, and unique molecular architecture. Although COFs are in their initial research stage, progress has been made in the design and synthesis of COF‐based electrocatalysis for the oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, and CO2 reduction in energy conversion and fuel generation. Design principles are also established for some of the COF materials toward rational design and rapid screening of the best electrocatalysts for a specific application. Herein, the recent advances in the design and synthesis of COF‐based catalysts for clean energy conversion and storage are presented. Future research directions and perspectives are also being discussed for the development of efficient COF‐based electrocatalysts.
Covalent organic frameworks (COFs) are promising for catalysis, sensing, gas storage, etc., owing to their large surface area, high crystallinity, tunable pore sizes, and unique molecular architecture. Recent advances in the design and synthesis of COF‐based catalysts for clean energy conversion and storage are presented. Design principles and future research directions for development of efficient COF‐based electrocatalysts are also discussed.
Direct conversion of CO2 into carbon‐neutral fuels or industrial chemicals holds a great promise for renewable energy storage and mitigation of greenhouse gas emission. However, experimentally ...finding an electrocatalyst for specific final products with high efficiency and high selectivity poses serious challenges due to multiple electron transfer, complicated intermediates, and numerous reaction pathways in electrocatalytic CO2 reduction. Here, an intrinsic descriptor that correlates the catalytic activity with the topological, bonding, and electronic structures of catalytic centers on M–N–C based single‐atom catalysts is discovered. The “volcano”‐shaped relationships between the descriptor and catalytic activity are established from which the best single‐atom catalysts for CO2 reduction are found. Moreover, the reaction mechanisms, intermediates, reaction pathways, and final products can also be distinguished by this new descriptor. The descriptor can also be used to predict the activity of the single‐atom catalysts for electrochemical reactions such as hydrogen evolution, oxygen reduction and evolution reactions in fuel cells and water‐splitting. These predictions are confirmed by the experimental results for onset potential and Faraday efficiency. The design principles derived from the descriptors open a door for rational design and rapid screening of highly efficient electrocatalysts for CO2 conversion as well as other electrochemical energy systems.
An intrinsic descriptor that correlates the catalytic activity with the topological, bonding, and electronic structures of catalytic centers on M–N–C based single‐atom catalysts is discovered. The “volcano”‐shaped relationships between the descriptor and catalytic activity are established from which the best single‐atom catalysts for CO2 reduction are found. The descriptor can also be used for other energy‐related electrochemical reactions.
Prolonged mechanical ventilation (PMV) is associated with poor outcomes and a high economic cost. The association between protein intake and PMV has rarely been investigated in previous studies. This ...study aimed to investigate the impact of protein intake on weaning from mechanical ventilation. Patients with the PMV (mechanical ventilation ≥6 h/day for ≥21 days) at our hospital between December 2020 and April 2022 were included in this study. Demographic data, nutrition records, laboratory data, weaning conditions, and survival data were retrieved from the patient’s electronic medical records. A total of 172 patients were eligible for analysis. The patients were divided into two groups: weaning success (n = 109) and weaning failure (n = 63). Patients with daily protein intake greater than 1.2 g/kg/day had significant shorter median days of ventilator use than those with less daily protein intake (36.5 vs. 114 days, respectively, p < 0.0001). Daily protein intake ≥1.065 g/kg/day (odds ratio: 4.97, p = 0.033), daily protein intake ≥1.2 g/kg/day (odds ratio: 89.07, p = 0.001), improvement of serum albumin (odds ratio: 3.68, p = 0.027), and BMI (odds ratio: 1.235, p = 0.014) were independent predictor for successful weaning. The serum creatinine level in the 4th week remained similar in patients with daily protein intake either >1.065 g/kg/day or >1.2 g/kg/day (p = 0.5219 and p = 0.7796, respectively). Higher protein intake may have benefits in weaning in patients with PMV and had no negative impact on renal function.
Tubulin post-translational modifications (PTMs) occur spatiotemporally throughout cells and are suggested to be involved in a wide range of cellular activities. However, the complexity and dynamic ...distribution of tubulin PTMs within cells have hindered the understanding of their physiological roles in specific subcellular compartments. Here, we develop a method to rapidly deplete tubulin glutamylation inside the primary cilia, a microtubule-based sensory organelle protruding on the cell surface, by targeting an engineered deglutamylase to the cilia in minutes. This rapid deglutamylation quickly leads to altered ciliary functions such as kinesin-2-mediated anterograde intraflagellar transport and Hedgehog signaling, along with no apparent crosstalk to other PTMs such as acetylation and detyrosination. Our study offers a feasible approach to spatiotemporally manipulate tubulin PTMs in living cells. Future expansion of the repertoire of actuators that regulate PTMs may facilitate a comprehensive understanding of how diverse tubulin PTMs encode ciliary as well as cellular functions.
Carbon nanomaterials are promising metal‐free catalysts for energy conversion and storage, but the catalysts are usually developed via traditional trial‐and‐error methods. To rationally design and ...accelerate the search for the highly efficient catalysts, it is necessary to establish design principles for the carbon‐based catalysts. Here, theoretical analysis and material design of metal‐free carbon nanomaterials as efficient photo‐/electrocatalysts to facilitate the critical chemical reactions in clean and sustainable energy technologies are reviewed. These reactions include the oxygen reduction reaction in fuel cells, the oxygen evolution reaction in metal–air batteries, the iodine reduction reaction in dye‐sensitized solar cells, the hydrogen evolution reaction in water splitting, and the carbon dioxide reduction in artificial photosynthesis. Basic catalytic principles, computationally guided design approaches and intrinsic descriptors, catalytic material design strategies, and future directions are discussed for the rational design and synthesis of highly efficient carbon‐based catalysts for clean energy technologies.
The theoretical analysis and material design of metal‐free carbon nanomaterials as efficient photo‐/electrocatalysts to facilitate critical chemical reactions in clean energy technologies are considered. Basic catalytic principles, computationally guided design approaches and descriptors, material design strategies, and future directions are discussed for the rational design and synthesis of highly efficient catalysts for clean energy conversion and storage.
Highly efficient electrocatalysts derived from metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) for oxygen reduction reaction (ORR) have been developed. However, the subsequent ...pyrolysis is often needed owing to their poor intrinsic electrical conductivity, leading to undesirable structure changes and destruction of the original fine structure. Now, hybrid electrocatalysts were formed by self‐assembling pristine covalent organic polymer (COP) with reduced graphene oxide (rGO). The electrical conductivity of the hybridized COP/rGO materials is increased by more than seven orders of magnitude (from 3.06×10−9 to 2.56×10−1 S m−1) compared with pure COPs. The ORR activities of the hybrid are enhanced significantly by the synergetic effect between highly active COP and highly conductive rGO. This COP/rGO hybrid catalyst exhibited a remarkable positive half‐wave (150 mV).
The heat is off: The self‐assembly of pyrolysis‐free covalent organic polymers having a well‐defined structure with conductive polymers is presented. This provides a way to precisely control the active sites at the atomic level for electrocatalysts.
Covalent organic frameworks (COFs), an emerging class of framework materials linked by covalent bonds, hold potential for various applications such as efficient electrocatalysts, photovoltaics, and ...sensors. To rationally design COF‐based electrocatalysts for oxygen reduction and evolution reactions in fuel cells and metal‐air batteries, activity descriptors, derived from orbital energy and bonding structures, are identified with the first‐principle calculations for the COFs, which correlate COF structures with their catalytic activities. The calculations also predict that alkaline‐earth metal‐porphyrin COFs could catalyze the direct production of H2O2, a green oxidizer and an energy carrier. These predictions are supported by experimental data, and the design principles derived from the descriptors provide an approach for rational design of new electrocatalysts for both clean energy conversion and green oxidizer production.
Covalent organic frameworks (COFs) hold potential for various applications. To rationally design COF‐based electrocatalysts, activity descriptors are identified with the first‐principle calculations. The calculations also predict that alkaline‐earth metal‐porphyrin COFs could catalyze direct production of H2O2, a green oxidizer. The design principles provide an approach for rational design of new electrocatalysts for both clean energy conversion and green oxidizer production.
MicroRNA miR-31 is implicated in the neoplastic process of various malignancies including oral squamous cell carcinoma (OSCC). Silent information regulator 3 (Sirtuin3 or SIRT3) is a NAD-dependent ...deacetylase that regulates metabolic process. Suppressor role of SIRT3 has been found in neoplasms. This study investigates the disruptions of miR-31-SIRT3 cascade to explore their potential association with metabolic change in OSCC. We identified that miR-31 directly targeted SIRT3 in OSCC cells, and a reverse correlation between miR-31 expression and SIRT3 expression was noted in OSCC tumors. SIRT3 expression attenuated the miR-31 enhanced tumor cell migration and invasion. It also reduced the tumorigenic potential of FaDu cell line. miR-31-SIRT3 impaired the mitochondrial membrane potential and structural integrity. The dis-regulation of this axis also contributed to the genesis of oxidative stress. In addition, miR-31 switched tumor cells from aerobic metabolism to glycolytic metabolism. This study provides novel evidences demonstrating the presence of miR-31-mediated post-transcriptional regulation of SIRT3 in OSCC. The disruption of miR-31-SIRT3 cascade and the consequential metabolic aberrances are involved in OSCC progression.
•miR-31 targets SIRT3 to drive OSCC invasion.•OSCC tumors exhibit miR-31 upregulation and SIRT3 downregulation.•miR-31-SIRT3 disruption underlies the mitochondrial disturbance.•miR-31-SIRT3 cascade induces ROS, glycolytic metabolism and lactate production.
In this letter, an on-chip electrostatic discharge (ESD) protection device was proposed for high-speed I/O interface circuits. A resistor-triggered silicon-controlled rectifier device with improved ...performance was designed and investigated in a nanoscale CMOS process. As verified in a 0.18-μm CMOS process, the proposed design exhibits a lower clamping voltage and low enough overshoot voltage during ESD stress conditions, and lower parasitic capacitance and low enough leakage current during normal circuit operating conditions. Therefore, the proposed design is suitable for ESD protection of high-speed circuits in low-voltage CMOS processes.
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