Latest ArticlesHard carbon is promising anode for potassium-ion batteries (PIBs), however, the poor rate capability hinders its development as potential anode. To address this question, we design a sulfur-doped porous hard carbon (S-HC) for PIBs through the combination of structural design and composition adjustment. The as-designed S-HC exhibits a long cycling life with ~191 mAh/g after 300 cycles at 1 A/g, and an excellent rate capability with ~100 mAh/g at 5 A/g, which was attributed to its structural characteristics and compositions. The S-HC demonstrates to be promising anode in the future.
A novel channel-wall engineering strategy of the porous materials cationic covalent organic frameworks (COFs) is established based on rapid microwave-assisted anion exchange reaction and utilized to prepare a set of new COFs. Due to the interaction between the carbon dioxide (CO2) and the acetate anion, the resulting SJTU-COF-AcO shows greatly enhanced carbon dioxide capacity up to 1.7 times of the pristine COF. The effect of the counter anions to CO2 capacity in the cationic COFs is investigated for the first time, which demonstrates that our channel-wall engineering strategy is a promising way to tailor the property of COFs for high CO2 capacity.
Fourteen avermectin B2a aglycon derivatives were designed and synthesized after removing the oleandrose disaccharide of avermectin B2a. Their structures were characterized by 1H NMR, 13C NMR, HMRS. Preliminary bioassays indicated that these compounds exhibited good insecticidal activity against diamondback moth at 200 mg/L, with mortality no less than 90%. Compounds 10b, 12a, 12c, 17 demonstrated good acaricidal activity against the adult mites, larvae, and good inhibition rate of hatching to mite eggs of Tetranychus cinnabarinus. Compounds 5, 10b, 10c exhibited excellent fungicidal activity against fourteen fungal pathogens in vitro. 3D-QSAR analysis showed that the fungicidal activity of avermectin B2a aglycon derivatives would be increased when a negatively charged and bulky group was introduced at 13-position, which will be instructive for the further modification of avermectin B2a aglycon.
Graphene oxide (GO) is widely used in the construction and application of various 2D membrane-based materials due to its unique colloidal structure. Herein, we demonstrate that micrometer-sized particles can make up freestanding membranes enabled by the extraordinary amphiphilic and polymer-like properties of graphene oxide through freeze casting. The 2D macromolecule, GO could well wrap the particles for better uniformity and stability in either dispersion or membrane. Importantly, freeze casting plays an important role in avoiding the severe aggregation of micrometer-sized particles in the solventremoving process. After reduction, the membrane exhibits good electrical conductivity while maintaining its integral structure, which can be directly used as a freestanding binder-free electrode. This work provides a universal approach to fabricate freestanding membranes with various micrometersized materials for energy storage.
Undesired adsorption of proteins brings big troubles to marine structures. The settled proteins change the physical and chemical properties of the surfaces, which allow marine fouling organisms to settle down on the structures. Therefore, to understand the adsorption mechanism of proteins is very helpful to find an environment-friendly solution against biofouling. Many approaches have been developed to study protein adsorption, but most of them are insufficient to give the chemical interaction information between proteins and surfaces. Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR) is an efficient, fast and non-destructive method for in situ surface measurement, which greatly minimizes the interference of water to infrared spectra, because of the very small depth of penetration of the evanescent wave. In this paper, an in situ FTIR-ATR technology was used to investigate the adsorption process of trypsin on a bare ZnSe surface and on a TiO2 coated ZnSe surface, and the effect of calcium cation strength and ultraviolet light irradiation on the secondary structure of trypsin were also evaluated. FTIR spectra of trypsin showed that Amide Ⅰ band red shift and Amide Ⅱ band blue shift in aqueous environment on both surfaces compared with the dry trypsin powder, and the addition of calcium cations further changed the Amide bands position, which indicated that the change of the secondary structure could be interfered by the environment. The hydrogen bond formation between water and trypsin, the interaction between surface and trypsin, the interaction between hydrated calcium cations and trypsin, are major factors to change the secondary structure of trypsin, and UV light irradiation also showed its influence for the secondary structure.
Cysteine (Cys) plays a pivotal role in many physiological and pathological processes, including detoxification and protein synthesis. The abnormal levels of Cys are linked to many diseases. In this study, a novel red-emitting off-on fluorescent probe Cys-TCF was masterly constructed for discriminative detection of Cys. After a series of experimental assessment, Cys-TCF displayed higher selectivity and sensitivity for Cys over other biothilols with a low detection limit (0.04 μmol/L). More notably, the probe was also successfully applied to image Cys in live cells and live zebrafishes with low cytotoxicity.
Gold nanoparticles functionalized hollow mesoporous Prussian blue nanoparticles (Au@HMPB NPs) were synthesized and its peroxidase-like activity was explored for electrochemical probe. The Au@HMPB NPs can reduce H2O2 at low detection potential of -0.1 V with high sensitivity. After physically adsorption of antibodies onto the gold nanoparticle surface, the functionalized nanoparticles were turned into immuno-probe. The soluble α-chain of interleukin-2 (IL-2) receptor (sCD25) was chosen as a model protein biomarker to test the performance of the probe. sCD25 in the samples were captured and enriched by capture anti-CD25 antibody functionalized magnetic nanospheres. Detection antibody functionalized Au@HMPB can then be linked onto the nanospheres and generate electrochemical current towards H2O2 reduction. The electrochemical responses to 1 mmol/L H2O2 was increased with the increasing concentration of CD25.
The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods. The product was characterized by X-ray diffraction, transmission electron microscopy and energy-dispersive X-ray spectroscopy. Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of -NH2 modified on 5'-end of probe DNA and Au@Bi2S3. Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect. The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L. The limit of detection was estimated to be 2 fmol/L (S/N=3). The biosensor also presents remarkable selectivity to distinguish fully complementary sequences from basemismatched and non-complementary ones, showing great promising in practical application.
TNFR1-associated death domain protein (TRADD) with arginine N-GlcNAcylation is a novel and structurally unique posttranslational modification (PTM) glycoprotein that blocks the formation of death-inducing signaling complex (DISC), orchestrating host nuclear factor kB (NF-kB) signaling in entero-pathogenic Escherichia coli (EPEC)-infected cells. This particular glycosylated modification plays an extremely vital role for the effective colonization and pathogenesis of pathogens in the gut. Herein we describe the total synthesis of TRADD death domain (residues 195-312) with arginine235 N-GlcNAcylation (Arg-GlcNAc TRADD (195-312)). Two longish peptidyl fragments of the wild-type primary sequence were obtained by robust, microwave-assisted, highly efficient, solid-phase peptide synthesis (SPPS), the N-GlcNAcylated sector was built by total synthesis and attached specifically to resinbound peptide with an unprotected ornithine residue via silver-promoted on-resin guanidinylation, Arg-GlcNAc TRADD (195-312) was constructed by hydrazide-based native chemical ligation (NCL). The facile synthetic strategy is expected to be generally applicable for the rapid synthesis of other proteins with Arg-GlcNAc modification and to pave the way for the related chemically biological study.
Hard carbon is regarded as promising anode materials for potassium-ion batteries (KIBs) owing to their low price and easy availability. However, the limited rate capability still needs to be improved. Herein, we demonstrate the fabrication of oxygen/sulfur co-doped hard carbon through a facile hydrolyzationsulfuration process of skimmed cotton. The simultaneous dopants significantly improve potassium ion diffusion rate. When served as the anode for KIBs, this hydrolyzed hard carbon delivered a high reversible capacity (409 mAh/g at 0.1 A/g), superior rate capability (135 mAh/g at 2 A/g) and excellent cyclability (about 120 mAh/g overt 500 cycles at 2 A/g). This work provides a facile strategy to prepare low-cost doped-hard carbon with superior potassium storage property.
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