A novel fluorescent probe based on a bisbinaphthyl structure has been designed and synthesized. This compound in combination with Zn(II) has exhibited highly enantioselective fluorescence ...enhancement with 13 common free amino acids. For example, its enantiomeric fluorescent enhancement ratios (ef or ΔI L/ΔI D) in the presence of the following amino acids are extremely high: 177 for valine, 199 for methionine, 186 for phenylalanine, 118 for leucine, and 89 for alanine. The observed high enantioselectivity and the extent of the substrate scope are unprecedented in the fluorescent recognition of free amino acids. This fluorescent probe can be applied to determine the enantiomeric composition of the structurally diverse chiral amino acids. NMR and mass spectroscopic investigations have provided clues to elucidate the observed high enantioselectivity.
The design and synthesis of 3D covalent organic frameworks (COFs) have been considered a challenge, and the demonstrated applications of 3D COFs have so far been limited to gas adsorption. Herein we ...describe the design and synthesis of two new 3D microporous base‐functionalized COFs, termed BF‐COF‐1 and BF‐COF‐2, by the use of a tetrahedral alkyl amine, 1,3,5,7‐tetraaminoadamantane (TAA), combined with 1,3,5‐triformylbenzene (TFB) or triformylphloroglucinol (TFP). As catalysts, both BF‐COFs showed remarkable conversion (96 % for BF‐COF‐1 and 98 % for BF‐COF‐2), high size selectivity, and good recyclability in base‐catalyzed Knoevenagel condensation reactions. This study suggests that porous functionalized 3D COFs could be a promising new class of shape‐selective catalysts.
A nifty net: Two novel 3D microporous base‐functionalized COFs (BF‐COFs, see structure of one framework), were synthesized by the condensation of a tetrahedral alkyl amine with two planar triangular building units, and their catalytic properties were explored in the Knoevenagel condensation reaction. Both BF‐COFs showed excellent catalytic activity with high conversion, excellent size selectivity, and good recyclability.
As members of the redox-flow battery (RFB) family, nonaqueous RFBs can offer a wide range of working temperature, high cell voltage, and potentially high energy density. These key features make ...nonaqueous RFBs an important complement of aqueous RFBs, broadening the spectrum of RFB applications. The development of nonaqueous RFBs is still at its early research stage and great challenges remain to be addressed before their successful use for practical applications. As such, it is essential to understand the major components in order to advance the nonaqueous RFB technology. In this perspective, three key major components of nonaqueous RFBs: organic solvents, supporting electrolytes, and redox pairs are selectively focused and discussed, with emphasis on providing an overview of those components and on highlighting the relationship between structure and properties. Urgent challenges are also discussed. To advance nonaqueous RFBs, the understanding of both components and systems is critically needed and it calls for inter-disciplinary collaborations across expertise including electrochemistry, organic chemistry, physical chemistry, cell design, and system engineering. In order to demonstrate the key features of nonaqueous RFBs, herein we also present an example of designing a 4.5 V ultrahigh-voltage nonaqueous RFB by combining a BP/BP&z.rad; super(-) redox pair and an OFN&z.rad; super(+)/OFN redox pair.
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The α- and β-tubulins are the major polypeptide components of microtubules (MTs), which are attractive targets for anticancer drug development. Indole derivatives display a variety of ...biological activities including antitumor activity. In recent years, a great number of indole derivatives as tubulin polymerization inhibitors have sprung up, which encourages medicinal chemists to pursue promising inhibitors with improved antitumor activities, excellent physicochemical, pharmacokinetic and pharmacodynamic properties. In this review, the recent progress from 2010 to present in the development of indole derivatives as tubulin polymerization inhibitors was summarized and reviewed, which would provide useful clues and inspirations for further design of outstanding tubulin polymerization inhibitors.
Developing low cost and highly active catalysts for the oxygen evolution reaction (OER) in an acidic medium is urgently indispensable for proton exchange membrane water electrolyzers (PEMWEs). ...Herein, we have prepared ultra-thin RuO
2
nanosheets (RuO
2
NSs) using a simple molten salt method. The as-prepared RuO
2
NSs with a thickness of 1-2 nm possess abundant defects. Toward the OER, the RuO
2
NSs achieve an extremely low overpotential of 199 mV at a current density of 10 mA cm
geo
−2
with a loading of 125 μg cm
geo
−2
. Furthermore, the RuO
2
NSs exhibit specific and mass activities of up to 0.89 mA cm
oxide
−2
and 0.52 A mg
Ru
−1
at 1.46 V
vs.
RHE, which are 14.9 and 80.6 times enhanced in specific and mass activity as compared to the commercial RuO
2
nanoparticles, respectively. In a homemade PEMWE, with RuO
2
NSs as the OER catalyst, the electrolyzer achieves a current density of 0.93 A cm
−2
at a cell voltage of 1.65 V without
iR
drop correction, which is 3 times larger than that of the commercial RuO
2
catalyst (0.31 A cm
−2
). Density functional theory calculations indicate that the Ru vacancy on the RuO
2
NS surfaces significantly weakens the binding energy of O* with respect to that of OOH*, which decreases the energy cost in the transformation from O* to OOH*, and thus dramatically enhances the OER performance. The unique defect-rich structure and outstanding performance demonstrate that the RuO
2
NSs possess great potential for developing high-performance PEMWEs.
A Ru vacancy decreases the energy barrier from O* to OOH*, thus dramatically enhancing the OER performance of defect-rich RuO
2
nanosheets.
Early prognostication of neurological outcome in comatose patients after cardiac arrest (CA) is vital for clinicians when assessing the survival time of sufferers and formulating appropriate ...treatment strategies to avoid the withdrawal of life‐sustaining treatment (WLST) from patients. However, there is still a lack of sensitive and specific serum biomarkers for early and accurate identification of these patients. Using an isobaric tag for relative and absolute quantitation (iTRAQ)‐based proteomic approach, we discovered 55 differentially expressed proteins, with 39 up‐regulated secreted serum proteins and 16 down‐regulated secreted serum proteins between three comatose CA survivors with good versus poor neurological recovery. Then, four proteins were selected and were validated via an enzyme‐linked immunosorbent assay (ELISA) approach in a larger‐scale sample containing 32 good neurological outcome patients and 46 poor neurological outcome patients, and it was confirmed that serum angiotensinogen (AGT) and alpha‐1‐antitrypsin (SERPINA1) were associated with neurological function and prognosis in CA survivors. A prognostic risk score was developed and calculated using a linear and logistic regression model based on a combination of AGT, SERPINA1 and neuron‐specific enolase (NSE) with an area under the curve of 0.865 (P < .001), and the prognostic risk score was positively correlated with the CPC value (R = 0.708, P < .001). We propose that the results of the risk score assessment not only reveal changes in biomarkers during neurological recovery but also assist in enhancing current therapeutic strategies for comatose CA survivors.
Nickel–phosphorus nanoparticles film on copper foam (Ni–P/CF) was prepared by electrodeposition. This electrocatalyst shows high catalytic activity and durability toward both hydrogen and oxygen ...evolution reactions in basic electrolytes. The results show that Ni–P/CF can deliver a current density of 10 mA cm−2 at an overpotential of 98 mV for hydrogen production and 325 mV for oxygen generating. A two-electrode water electrolyzer using Ni–P/CF as cathode and anode produces 10 mA cm−2 at a cell voltage of 1.68 V with high stability.
•Ni–P/CF can act as bifunctional HER and OER electrocatalyst in basic electrolytes.•Ni–P/CF exhibits high catalytic activity towards both HER and OER.•Ni–P/CF can achieve 10 mA cm−2 water-splitting current at a cell voltage of 1.68 V.
A simple self-crosslinking strategy, without the needs of a separate crosslinker or a catalyst, is reported here. The crosslinking drastically lowers the water swelling ratio (e.g., 5-10 folds ...reduction) and provides excellent solvent-resistance. The self-crosslinked membrane (DCL: 5.3%) shows the highest IEC-normalized hydroxide conductivity among all crosslinked HEMs reported.
Caffeic acid phenethyl ester (CAPE) is a rare natural ingredient with several biological activity, but the industrial production of CAPE using lipase-catalyzed esterification of caffeic acid (CA) and ...2-phenylethanol (PE) in ionic liquids is hindered by low substrate concentrations and a long reaction time. To establish a high-efficiency bioprocess for obtaining CAPE, a novel continuous flow biosynthesis of CAPE from alkyl caffeate and PE in BmimTf2N using a packed bed microreactor was successfully carried out. Among the tested alkyl caffeates and lipases, methyl caffeate and Novozym 435, respectively, were selected as the suitable substrate and biocatalyst. Under the optimum conditions selected using response surface methodology, a 93.21% CAPE yield was achieved in 2.5h using a packed bed microreactor, compared to 24h using a batch reactor. The reuse of Novozym 435 for 20 cycles and continuous reaction for 9 days did not result in any decrease in activity.
HIV-1 integrase (IN) is a key enzyme in viral replication that catalyzes the covalent integration of viral cDNA into the host genome. Currently, five HIV-1 IN strand transfer inhibitors (INSTIs) are ...approved for clinical use. These drugs represent an important addition to the armamentarium for antiretroviral therapy. This review briefly illustrates the development history of INSTIs. The characteristics of the currently approved INSTIs, as well as their future perspectives, are critically discussed.
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•HIV-1 integrase is an essential enzyme for retroviral replication.•This review is focused on the development history of INSTIs.•The characteristics of the FDA approved INSTIs are depicted.
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