Latest ArticlesA friendly biomimetic process was adopted for the mild preparation of "all-inclusive" organic-inorganic nanospheres, which effectively integrate biorecognition function and signal amplification function. The resulted Ca3(PO4)2-Ab2-BSA nanospheres were employed as signal labels for enhancing detection of nuclear matrix protein 22 (NMP 22). The fabricated electrochemical immunosensor exhibited a linear range (0.08-77.00 U/mL) and an ultralow limit of detection (0.01 U/mL) towards NMP 22, which can be taken as a promising tool for clinical diagnosis of bladder cancer.
Peptide amphiphiles with well-organized secondary structure are an important family of molecules that are known to assemble into a variety of nanostructures. In this work, we present three guanidiniocarbonylpyrrole (GCP) containing peptide amphiphiles, which show versatile morphology and secondary structure changes as a result of different chain lengths and in different concentration regimes. The random coil conformation, α-helix, and β-sheet are obtained for peptide 1, peptide 2, and peptide 3, respectively under neutral aqueous conditions. Furthermore, all peptide amphiphiles can aggregate to form nanoparticles at low concentrations. However, at high concentrations, peptide 1 selfassembles into left-handed twisted helical fibers, while longer bamboo-like morphology can be observed exclusively for peptide 2. For peptide 3, freshly prepared samples show uniform spherical morphology, whereas an obvious morphological transition from original nanoparticles to disordered fibers was realized after incubating for one week. These fascinating morphology changes were determined by the combination of circular dichroism, dynamic light scattering, transmission electron microscopy, atomic force microscopy, and theoretical calculations.
MnS as anode material for sodium-ion batteries (SIBs) has recently attracted great attention because of the high theoretical capacity, great natural abundance, and low cost. However, it suffers from inferior electrical conductivity and large volume expansion during the charge/discharge process, leading to tremendous damage of electrodes and subsequently fast capacity fading. To mitigate these issues, herein, a three-dimensional (3D) interlaced carbon nanotubes (CNTs) threaded into or between MnS hollow microspheres (hollow MnS/CNTs composite) has been designed and synthesized as an enhanced anode material. It can effectively improve the electrical conductivity, buffer the volume change, and maintain the integrity of the electrode during the charging and discharging process based on the synergistic interaction and the integrative structure. Therefore, when evaluated as anode for SIBs, the hollow MnS/CNTs electrode displays enhanced reversible capacity (275 mAh/g at 100 mA/g after 100 cycles), which is much better than that of pure MnS electrode (25 mAh/g at 100 mA/g after 100 cycles) prepared without the addition of CNTs. Even increasing the current density to 500 mA/g, the hollow MnS/CNTs electrode still delivers a five times higher reversible capacity than that of the pure MnS electrode. The rate performance of the hollow MnS/CNTs electrode is also superior to that of pure MnS electrode at various current densities from 50 mA/g to 1000 mA/g.
Extensive structure-activity relationships (SARs) study of JND3229 was conducted to yield a series of new reversible 2-oxo-3, 4-dihydropyrimido[4, 5-d]pyrimidine privileged scaffold as EGFRC797S inhibitors. One of the most potent compound 6i potently suppressed EGFRL858R/T790M/C797S kinase with an IC50 value of 3.1 nmol/L, and inhibited the proliferation of BaF3 cells harboring EGFRL858R/T790M/C797S and EGFR19D/T790M/C797S mutants with IC50 values of 290 nmol/L and 316 nmol/L, respectively. Further, 6i dose-dependently induced suppression of the phosphorylation of EGFRL858R/T790M/C797S and EGFR19D/T790M/C797S in BaF3 cells. Compound 6i may serve as a promising lead compound for further drug discovery overcoming the acquired resistance of non-small cell lung cancer (NSCLC) patients.
In this study, we report a new small molecule acceptor (named TT-4F) which uses 3, 6-dimethoxylthieno[3, 2-b]thiophene (TT) as the π-bridge. Addition of 0.05 weight ratio amount of TT-4F into the host binary blend of PTB7-Th:IEICO-4F, resulting in a ternary blend in a weight ratio of 1:1:0.05, enables increased open-circuit voltage (Voc), short-circuit current-density (Jsc), and fill-factor (FF) at the same time. Finally, 12.1% efficiency is obtained. Compared to the 3-(2-ethylhexyloxylthiophene) bridge on IEICO-4F, the additional methoxyl group on the TT-6 position is involved in the lowest unoccupied molecular orbital (LUMO) and the larger π-system on TT increases the electron-donating nature, both of which help to raise the LUMO level, one reason of the increased Voc. Upon addition of 0.05 TT-4F, the hole mobility is increased, the monomolecular recombination is reduced, and the charge dissociation and collection is enhanced. All of these contribute to the increased Jsc and FF.
Developing high efficiency and low cost electrocatalysts is critical for the enhancement of oxygen reduction reaction (ORR), which is the fundamental for the development and commercialization of renewable energy conversion technology. Herein, zinc-nitrogen-carbon (Zn-N-C) was prepared by using biomass resource chitosan via a facile carbon bath method. The obtained Zn-N-C delivered a high specific surface area (794.7 cm2 /g) together with pore volume (0.49 cm3 /g). During the electrochemical evaluation of oxygen reduction reaction (ORR), Zn-N-C displayed high activity for ORR with an onset potential E0=0.96 VRHE and a half wave potential E1/2=0.86 VRHE, which were more positive than those of the commercial 20 wt% Pt/C benchmark catalyst (E0=0.96 VRHE and E1/2=0.81 VRHE). In addition, the ZnN-C catalyst also had a better stability and methanol tolerance than those of the Pt/C catalyst.
Partially biobased polysilylethers (PSEs) are synthesized via dehydrocoupling polymerization catalyzed by an anionic iridium complex. Different types (AB type or AA and BB type) of monomers are suitable. Levulinic acid (LA) and succinic acid (SA) have been ranked within the top 10 chemicals derived from biomass. BB type monomers (diols) derived from LA and SA have been applied to the synthesis of PSEs. The polymerization reactions employ an air-stable anionic iridium complex bearing a functional bipyridonate ligand as catalyst. Moderate to high yields of polymers with number-average molecular weights (Mn) up to 4.38× 104 were obtained. A possible catalytic cycle via an Ir-H species is presented. Based on the results of kinetic experiments, apparent activation energy of polymerization in the temperature range of 0-10 ℃ is about 38.6 kJ/mol. The PSEs synthesized from AA and BB type monomers possess good thermal stability (T5=418 ℃ to 437 ℃) and low glass-transition temperature (Tg=-49.6 ℃).
Rhenium is one of important components for heterogeneous catalysts, which has been recently used for the catalytic reactions related to the production of biomass-derived chemicals such as deoxydehydration of vicinal OH groups, C-O hydrogenolysis, and hydrogenation of carboxylic acids, and so on. Suitable oxidation state of Re as a catalytic active species is strongly dependent on the catalytic reactions. The control of the oxidation state of Re species on the catalysts is crucial on the catalyst development.
In this study, flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method. The hydrothermal process was optimized and the effects of hydrothermal condition, including reaction temperature, reaction time and the ratio of Mo source to S source (Mo:S) in precursor, on microwave absorption performances and dielectric properties were investigated. Our results showed that when the reaction temperature was 180℃, the reaction time was 18 h, and the Mo:S was 1:3.5, the synthesized MoS2 had the best performance:Its minimum reflection loss could reach -55.78 dB, and the corresponding matching thickness was 2.30 mm with a wide effective bandwidth of 5.17 GHz. Further researches on the microwave absorption mechanism revealed that in addition to the destructive interference of electromagnetic waves, various polarization phenomena such as defect dipole polarization were the main reasons for microwave loss. We believe that MoS2 is a candidate for a practical microwave absorbent.
(+)-6-3'a, 7-6'-Isowallichilide and (-)-6-3'a, 7-6'-isowallichilide, a pair of enantiomeric phthalide dimers featuring new 6-3'a, 7-6' dimerization sites, were isolated from Ligusticum chuanxiong. The structures were elucidated by NMR spectroscopy and X-ray diffraction analysis. Furthermore, the absolute configurations were assigned using experimental and theoretical electronic circular dichroism methods. Their nitric oxide inhibition, antiplatelet aggregation and antioxidant activities were investigated.
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