Recently, the emergence of photoactive metal–organic frameworks (MOFs) has given great prospects for their applications as photocatalytic materials in visible‐light‐driven hydrogen evolution. Herein, ...a highly photoactive visible‐light‐driven material for H2 evolution was prepared by introducing methylthio terephthalate into a MOF lattice via solvent‐assisted ligand‐exchange method. Accordingly, a first methylthio‐functionalized porous MOF decorated with Pt co‐catalyst for efficient photocatalytic H2 evolution was achieved, which exhibited a high quantum yield (8.90 %) at 420 nm by use sacrificial triethanolamine. This hybrid material exhibited perfect H2 production rate as high as 3814.0 μmol g−1 h−1, which even is one order of magnitude higher than that of the state‐of‐the‐art Pt/MOF photocatalyst derived from aminoterephthalate.
The in visible MOF: A high performance for visible‐light‐driven H2‐evolution is obtained with a new methylthio‐functionalized metal–organic framework (MOF) photocatalyst that is rationally designed and facilely prepared. This approach opens up a new way to achieve photocatalysis based on MOF materials with high quantum efficiency value (up to 8.9 %) and excellent photoactivity.
Spasticity and weakness (spastic paresis) are the primary motor impairments after stroke and impose significant challenges for treatment and patient care. Spasticity emerges and disappears in the ...course of complete motor recovery. Spasticity and motor recovery are both related to neural plasticity after stroke. However, the relation between the two remains poorly understood among clinicians and researchers. Recovery of strength and motor function is mainly attributed to cortical plastic reorganization in the early recovery phase, while reticulospinal (RS) hyperexcitability as a result of maladaptive plasticity, is the most plausible mechanism for poststroke spasticity. It is important to differentiate and understand that motor recovery and spasticity have different underlying mechanisms. Facilitation and modulation of neural plasticity through rehabilitative strategies, such as early interventions with repetitive goal-oriented intensive therapy, appropriate non-invasive brain stimulation, and pharmacological agents, are the keys to promote motor recovery. Individualized rehabilitation protocols could be developed to utilize or avoid the maladaptive plasticity, such as RS hyperexcitability, in the course of motor recovery. Aggressive and appropriate spasticity management with botulinum toxin therapy is an example of how to create a transient plastic state of the neuromotor system that allows motor re-learning and recovery in chronic stages.
Transformation of CO2 based on metal−organic framework (MOF) catalysts is becoming a hot research topic, not only because it will help to reduce greenhouse gas emission, but also because it will ...allow for the production of valuable chemicals. In addition, a large number of impressive products have been synthesized by utilizing CO2. In fact, it is the formation of new covalent bonds between CO2 and substrate molecules that successfully result in CO2 solidly inserting into the products, and only four types of new CX bonds, including CH, CC, CN, and CO bonds, are observed in this exploration. An overview of recent progress in constructing CX bonds for CO2 conversion catalyzed by various MOF catalysts is provided. The catalytic mechanism of generating different CX bonds is further discussed according to both structural features of MOFs and the interactions among CO2, substrates, as well as MOFs. The future opportunities and challenges in this field are also tentatively covered.
The transformation of CO2 into value‐added chemicals has received particular attention in recent years. The formation of covalent bonds between CO2 and substrates catalyzed by metal–organic frameworks are summarized. The catalytic mechanism of generating different CX bonds is discussed. The critical challenges and potential solutions, future opportunities and prospects in this field are also covered.
Resurfacing perovskite nanocrystals (NCs) with tight‐binding and conductive ligands to resolve the dynamic ligands—surface interaction is the fundamental issue for their applications in perovskite ...light‐emitting diodes (PeLEDs). Although various types of surface ligands have been proposed, these ligands either exhibit weak Lewis acid/base interactions or need high polar solvents for dissolution and passivation, resulting in a compromise in the efficiency and stability of PeLEDs. Herein, we report a chemically reactive agent (Iodotrimethylsilane, TMIS) to address the trade‐off among conductivity, solubility and passivation using all‐inorganic CsPbI3 NCs. The liquid TMIS ensures good solubility in non‐polar solvents and reacts with oleate ligands and produces in situ HI for surface etching and passivation, enabling strong‐binding ligands on the NCs surface. We report, as a result, red PeLEDs with an external quantum efficiency (EQE) of ≈23 %, which is 11.2‐fold higher than the control, and is among the highest CsPbI3 PeLEDs. We further demonstrate the universality of this ligand strategy in the pure bromide system (CsPbBr3), and report EQE of ≈20 % at 640, 652, and 664 nm. This represents the first demonstration of a chemically reactive ligand strategy that applies to different systems and works effectively in red PeLEDs spanning emission from pure‐red to deep‐red.
A solution‐phase ligand exchange strategy is used to resurface perovskite nanocrystal surfaces with a chemically active, short and conductive ligand, Iodotrimethylsilane (TMIS), which also functions as a surface passivant. Excellent conductivity and photostability allowed us to fabricate compact, high‐mobility and trap‐free perovskite NC films with high PLQY (>90%). As a result, we achieve CsPbI3 NC‐based PeLEDs with an EQE of ~23%.
Perovskite light‐emitting diodes (LEDs) emitting in the pure‐red range of 630–640 nm show promise in meeting the requirement of the Rec.2100 standard for high‐resolution displays. However, the ...high‐performing LEDs (external quantum efficiency, EQE >20%) in the pure‐red range suffer from half‐life time (luminance drop to 50% of the initial luminance) of <1.6 h, resulting from the injection/transportation barrier and surface‐defects–induced charge carrier quenching. Herein, a bi‐ligand synergy strategy is developed to address the T50 issue: the introduction of iodide‐rich ligands with different chain length increases the vacancy formation energy of halogen ions and enhances the exciton binding energy, resulting in a high photoluminescence quantum yield of over 92%. The treated CsPbBrx/I3−x films exhibit 34‐fold improved material stability related to the control at continuous aging at 100 °C. As a result, pure‐red LEDs with CIE coordinates of (0.698, 0.301) approaching the Rec.2100 standard are reported. These pure‐red LEDs exhibit a low turn‐on voltage of 1.8 V, which is the lowest among reported pure‐red perovskite LEDs, and even 0.15 V lower than the optical bandgap energy (1.95 eV); and a maximum EQE of ≈21% with fourfold enhanced T50 relative to the best previous pure‐red perovskite LEDs.
The iodide‐rich ligands in the bi‐ligand synergy strategy increase the vacancy formation energy of halogen ions, resulting in a high photoluminescence quantum yield of over 92%. The light‐emitting diodes exhibit a maximum external quantum efficiency of ≈21% with fourfold enhanced T50 relative to the best previous pure‐red perovskite light‐emitting diodes.
The transcription factor hypoxia inducible factor-1α (HIF-1α) mediates adaptive responses to oxidative stress by nuclear translocation and regulation of gene expression. Mitochondrial changes are ...critical for the adaptive response to oxidative stress. However, the transcriptional and non-transcriptional mechanisms by which HIF-1α regulates mitochondria in response to oxidative stress are poorly understood. Here, we examined the subcellular localization of HIF-1α in human cells and identified a small fraction of HIF-1α that translocated to the mitochondria after exposure to hypoxia or H2O2 treatment. Moreover, the livers of mice with CCl4-induced fibrosis showed a progressive increase in HIF-1α association with the mitochondria, indicating the clinical relevance of this finding. To probe the function of this HIF-1α population, we ectopically expressed a mitochondrial-targeted form of HIF-1α (mito-HIF-1α). Expression of mito-HIF-1α was sufficient to attenuate apoptosis induced by exposure to hypoxia or H2O2-induced oxidative stress. Moreover, mito-HIF-1α expression reduced the production of reactive oxygen species, the collapse of mitochondrial membrane potential, and the expression of mitochondrial DNA-encoded mRNA in response to hypoxia or H2O2 treatment independently of nuclear pathways. These data suggested that mitochondrial HIF-1α protects against oxidative stress induced-apoptosis independently of its well-known role as a transcription factor.
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•HIF-1α is recruited to mitochondria in response to oxidative stress.•Mitochondrial HIF-1α protects against oxidative stress induced apoptosis.•HIF-1α in mitochondria reduces ROS levels and reverses mitochondrial damage.•Mitochondrial HIF-1α reduces mtDNA encoded mRNA levels.•Mitochondrial HIF-1α may involve in liver fibrosis.
Separation is an important industrial step with critical roles in the chemical, petrochemical, pharmaceutical, and nuclear industries, as well as in many other fields. Although much progress has been ...made, the development of better separation technologies, especially through the discovery of high‐performance separation materials, continues to attract increasing interest due to concerns over factors such as efficiency, health and environmental impacts, and the cost of existing methods. Metal–organic frameworks (MOFs), a rapidly expanding family of crystalline porous materials, have shown great promise to address various separation challenges due to their well‐defined pore size and unprecedented tunability in both composition and pore geometry. In the past decade, extensive research is performed on applications of MOF materials, including separation and capture of many gases and vapors, and liquid‐phase separation involving both liquid mixtures and solutions. MOFs also bring new opportunities in enantioselective separation and are amenable to morphological control such as fabrication of membranes for enhanced separation outcomes. Here, some of the latest progress in the applications of MOFs for several key separation issues, with emphasis on newly synthesized MOF materials and the impact of their compositional and structural features on separation properties, are reviewed and highlighted.
The development of advanced separation materials is central to address challenging separation tasks in a number of essential industrial processes in the petrochemical, pharmaceutical, and nuclear industries. The emerging class of metal–organic frameworks (MOFs) has shown a great promise. The latest advances in MOF materials used for such applications are reviewed.
It is thought that KRAS oncoproteins are constitutively active because their guanosine triphosphatase (GTPase) activity is disabled. Consequently, drugs targeting the inactive or guanosine ...5′-diphosphate–bound conformation are not expected to be effective. We describe a mechanism that enables such drugs to inhibit KRASG12C signaling and cancer cell growth. Inhibition requires intact GTPase activity and occurs because drug-bound KRASG12C is insusceptible to nucleotide exchange factors and thus trapped in its inactive state. Indeed, mutants completely lacking GTPase activity and those promoting exchange reduced the potency of the drug. Suppressing nucleotide exchange activity downstream of various tyrosine kinases enhanced KRASG12C inhibition, whereas its potentiation had the opposite effect. These findings reveal that KRASG12C undergoes nucleotide cycling in cancer cells and provide a basis for developing effective therapies to treat KRASG12C-driven cancers.
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