Transition-metal-catalyzed alkene hydrosilylation is one of the most important homogeneous catalytic reactions, and the development of methods that use base metals, especially iron, as catalysts for ...this transformation is a growing area of research. However, the limited number of ligand scaffolds applicable for base-metal-catalyzed alkene hydrosilylation has seriously hindered advances in this area. Herein, we report the use of 1,10-phenanthroline ligands in base-metal catalysts for alkene hydrosilylation. In particular, iron catalysts with 2,9-diaryl-1,10-phenanthroline ligands exhibit unexpected reactivity and selectivity for hydrosilylation of alkenes, including unique benzylic selectivity with internal alkenes, Markovnikov selectivity with terminal styrenes and 1,3-dienes, and excellent activity toward aliphatic terminal alkenes. According to the mechanistic studies, the unusual benzylic selectivity of this hydrosilylation initiates from π-π interaction between the phenyl of the alkene and the phenanthroline of the ligand. This ligand scaffold and its unique catalytic model will open possibilities for base-metal-catalyzed hydrosilylation reactions.
Tremendous demands for renewable hydrogen generated from water splitting have stimulated intensive research on developing earth‐abundant, non‐noble, and versatile metal catalysts toward the hydrogen ...evolution reactions (HER). Here, self‐supported Cu‐Ni‐Al hybrid electrodes that are composed of electroactive Al7Cu4Ni@Cu4Ni core/shell nanocrystals seamlessly integrated in self‐supported 3D bimodal nanoporous Cu skeleton (Bi‐NP Cu/Al7Cu4Ni@Cu4Ni) as robust HER electrocatalysts in alkaline electrolyte are reported. As a result of the proper architecture, in which the Bi‐NP Cu skeleton not only facilitates both electron and electrolyte transports but also provides high specific surface areas to fully use high electrocatalytic activity of Al7Cu4Ni@Cu4Ni core/shell nanocrystals, the Bi‐NP Cu/Al7Cu4Ni@Cu4Ni hybrid catalysts exhibit a low onset overpotential of 60 mV and a small Tafel slope of 110 mV dec−1, enabling the catalytic current density of 10 mA cm−2 at a low overpotential of 139 mV. The highly stable electrochemical performance makes them promising candidates as cathode catalysts in alkaline‐based devices.
Self‐supported bimodal nanoporous Cu‐Ni‐Al catalytic electrodes are successfully developed as robust hydrogen evolution reaction (HER) electrocatalysts in alkaline electrolyte. These hybrid electrodes that are composed of electroactive Al7Cu4Ni@Cu4Ni core/shell nanocrystals seamlessly integrated in a 3D bimodal nanoporous Cu skeleton (Bi‐NP Cu/Al7Cu4Ni@Cu4Ni) exhibit exceptional HER performance as a result of enhanced electrolyte accessibility and electron transport as well as HER catalytic activity.
Conventional metasurface holograms relying on metal antennas for phase manipulation suffer from strong Ohmic loss and incomplete polarization conversion. The efficiency is limited to rather small ...values when operating in transmission mode. Here, we implement a high-efficiency transmissive metasurface hologram by leveraging the recently developed Huygens' metasurface to construct an electric and magnetic sheet with a transmission efficiency up to 86% and optical efficiency of 23.6%. The high-efficiency originates from the simultaneous excitations of the Mie-type electric and magnetic dipole resonances in the meta-atoms composed of silicon nanodisks. Our hologram shows high fidelity over a wide spectral range and promises to be an outstanding alternative for display applications.
We have disclosed an alkenes dicarbofunctionalization method to introduce alkyl and electron‐rich aryl across the C=C bond of styrenes under copper catalyst and oxidative conditions, leading to ...construct C(sp3)‐C(sp2)/C(sp3)‐C(sp3) bonds via dual C−H functionalization. This method realizes the synthesis of 1,1‐diarylalkanes, which are very important skeleton in natural products and drug molecules, through the grafting of electron‐rich aromatics, including indoles, pyrroles, trisubstituted aromatic.
A highly para-selective amination of anilines with phenothiazines for producing various functionalized 10-aryl-10H-phenothiazines is reported. The oxidative amination reaction proceeds ...electrochemically at room temperature, thereby avoiding the use of metals and oxidizing reagents with excellent functional group tolerance and broad substrate scope.
A new, practical directed anodic C-H sulfonylation of N,N-disubstituted anilines with sodium sulfinates for producing o- or p-amino arylsulfones and diarylsulfones is described. Employing the anodic ...strategy, the reaction proceeds efficiently under mild (room temperature) and transition-metal- and chemical oxidant-free conditions, and enables the formation of C-S bonds via directed activation of ortho- or para-C-H bond to the amino group with broad substrate scope and excellent site selectivity.
Abstract
Salt tolerance in plants is mediated by Na+ extrusion from the cytosol by the plasma membrane Na+/H+ antiporter SOS1. This is activated in Arabidopsis root by the protein kinase complex ...SOS2–SOS3 and in Arabidopsis shoot by the protein kinase complex CBL10–SOS2, with SOS2 as a key node in the two pathways. The sos1 mutant is more sensitive than the sos2 mutant, suggesting that other partners may positively regulate SOS1 activity. Arabidopsis has 26 CIPK family proteins of which CIPK8 is the closest homolog to SOS2. It is hypothesized that CIPK8 can activate Na+ extrusion by SOS1 similarly to SOS2. The plasma membrane Na+/H+ exchange activity of transgenic yeast co-expressing CBL10, CIPK8, and SOS1 was higher than that of untransformed and SOS1 transgenic yeast, resulting in a lower Na+ accumulation and a better growth phenotype under salinity. However, CIPK8 could not interact with SOS3, and the co-expression of SOS3, CIPK8, and SOS1 in yeast did not confer a significant salt tolerance phenotype relative to SOS1 transgenic yeast. Interestingly, cipk8 displayed a slower Na+ efflux, a higher Na+ level, and a more sensitive phenotype than wild-type Arabidopsis, but grew better than sos2 under salinity stress. As expected, sos2cipk8 exhibited a more severe salt damage phenotype relative to cipk8 or sos2. Overexpression of CIPK8 in both cipk8 and sos2cipk8 attenuated the salt sensitivity phenotype. These results suggest that CIPK8-mediated activation of SOS1 is CBL10-dependent and SOS3-independent, indicating that CIPK8 and SOS2 activity in shoots is sufficient for regulating Arabidopsis salt tolerance.
In Arabidopsis, the Na+/H+ antiporter SOS1, which functions in salt tolerance, is activated by the protein kinase complex CBL10–CIPK8 in shoots, independent of the root activator SOS3.
Magnetic nanoparticles (MNPs) are promising candidates for drug delivery and treatment of various disorders. Toxicity evaluation is a critical point in the development of nanoformulations and ...therefore, draws considerable attention. Formulations involving individual or combinatorial nanoparticle suspensions might be used for targeted delivery and treatment. This might be a evaluated further for safety related issues considering future medications based on MNPs. Nanoparticle distribution in the body is dependent on its surface characteristics. Size, dose and routes of nanoparticle entry have to be taken into consideration for future assays.
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Mutual interference is a severe issue that occurs during the electrochemical detection of heavy metal ions. This limitation presents a notable drawback for its high sensitivity to specific targets. ...Here, we present a high electrochemical sensitivity of ∼237.1 μA cm–2 μM–1 toward copper(II) Cu(II) based on oxygen-deficient titanium dioxide (TiO2–x ) nanosheets. We fully demonstrated an atomic-level relationship between electrochemical behaviors and the key factors, including the high-energy (001) facet percentage, oxygen vacancy concentration, surface −OH content, and charge carrier density, is fully demonstrated. These four factors were quantified using Raman, electron spin resonance, X-ray photoelectron spectroscopy spectra, and Mott–Schottky plots. In the mutual interference investigation, we selected cadmium(II) Cd(II) as the target ion because of the significant difference in its stripping potential (∼700 mV). The results show that the Cd(II) can enhance the sensitivity of TiO2–x nanosheets toward Cu(II), exhibiting an electron-induced mutual interference effect, as demonstrated by X-ray absorption fine structure spectra.
•rFSAV is a novel recombinant five-antigen Staphylococcus aureus vaccine.•rFSAV was assessed in patients undergoing elective surgery for closed fractures for the first time.•rFSAV is safe, well ...tolerated in patients undergoing elective surgery for closed fractures.•rFSAV elicits rapid and robust specific humoral immune responses in targeted population.•rFSAV is worth further evaluation in in phase 3 studies in a larger number of individuals.
Vaccines are urgently required to control Staphylococcus aureus hospital and community infections and reduce the use of antibiotics. Here, we report the safety and immunogenicity of a recombinant five-antigen Staphylococcus aureus vaccine (rFSAV) in patients undergoing elective surgery for closed fractures.
A randomized, double-blind, placebo-controlled, multicenter phase 2 clinical trial was carried out in 10 clinical research centers in China. Patients undergoing elective surgery for closed fractures, aged 18–70 years, were randomly allocated at a ratio of 1:1 to receive the rFSAV or placebo at a regimen of two doses on day 0 and another dose on day 7. All participants and investigators remained blinded during the study period. The safety endpoint was the incidence of adverse events within 180 days. The immunogenicity endpoints included the level of specific antibodies to five antigens after vaccination, as well as opsonophagocytic antibodies.
A total of 348 eligible participants were randomized to the rFSAV (n = 174) and placebo (n = 174) groups. No grade 3 local adverse events occurred. There was no significant difference in the incidence of overall systemic adverse events between the experimental (40.24 %) and control groups (33.72 %) within 180 days after the first immunization. The antigen-specific binding antibodies started to increase at days 7 and reached their peaks at 10–14 days after the first immunization. The rapid and potent opsonophagocytic antibodies were also substantially above the background levels.
rFSAV is safe and well-tolerated in patients undergoing elective surgery for closed fractures. It elicited rapid and robust specific humoral immune responses using the perioperative immunization procedure. These results provide evidence for further clinical trials to confirm the vaccine efficacy.
China's Drug Clinical Trials Registration and Information Publicity Platform registration number: CTR20181788. WHO International Clinical Trial Registry Platform identifier: ChiCTR2200066259.
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