Quenching-induced interfacial amorphous layer containing atomic Ag on Fe2O3 nanosphere for high-performance lithium-ion batteries and mechanism.

The interfacial effect of nanomaterials plays a key role in their electrochemical performance when used in lithium-ion batteries (LIBs), but interfacial modification is a big challenging. Herein, a composite Fe2O3 nanoparticles with atomic Ag/amorphous layers were successfully prepared by co-deposition and subsequent quenching method. Compared to pristine Fe2O3, it maintains a higher capacity and longer cycle life in LIBs, with a capacity of 1150 mAh g-1 after 600 cycles at 0.5 Ag-1, and a long 1800 cycles at a current density of 5 Ag-1 after activation. Detailed experiments and Ex-situ TEM demonstrate that the fusion of surface particles occurred after calcination and quenching treatment, resulting in amorphous layers. The amorphous layer can act as a stabilizer during cycling, which protects the overall nanospheres structure from collapsing and thus leads to ultra-long cycling life. Our findings shed light on the surface modification of nanoscale materials and provides a manner to enhance the electrochemical performance of nanomaterials for LIBs.

Polymer-capped CdSe/ZnS quantum dots for the sensitive detection of Cu2+ and Hg2+ and the quenching mechanism.

In this work, poly(styrene-co-maleic anhydride)-capped CdSe/ZnS quantum dots (QDs) aminolyzed with ethanolamine are proposed as fluorescent probes for the detection of Cu2+ and Hg2+, and two different quenching mechanisms are discussed in detail. The coordination abilities of the surface polymer of CdSe/ZnS QDs and two metal ions are calculated by density functional theory (DFT). The photoinduced electron transfer from excited QDs to Cu2+ unoccupied orbitals is enhanced due to the coordination between Cu2+ and the surface polymer of QDs. The electron transfer consumes non-radiative energy and performs fluorescence quenching. For Hg2+, the formation of HgS and the slight aggregation of polymer-coated CdSe/ZnS QDs lead to fluorescence quenching. The probe is sensitive to both Cu2+ and Hg2+, and the response can be detected within 1 min without adjusting the pH. With the addition of a masking agent, Cu2+ and Hg2+ can be exclusively detected in coexistence with another ion. For Cu2+, a linear relation in the concentration ranging from 0.02 to 0.7 µM was found between the relative fluorescence intensity (F0/F) and the concentration of Cu2+; the limit of detection (S/N = 3) is 6.94 nM. For Hg2+, a linear relation ranging from 0.1 to 1.4 µM was found between ln(F0/F) and the concentration of Hg2+; the limit of detection is 20.58 nM.

Glucosamine-modified polyethylene glycol hydrogel-mediated chondrogenic differentiation of human mesenchymal stem cells.

Glucosamine (GA) is an important cartilage matrix precursor for the glycosaminoglycan biochemical synthesis, and has positive effects on cartilage regeneration, particularly in osteoarthritis therapy. However, it has not been used as a bioactive group in scaffolds for cartilage repair widely. In this study, we synthesized modified polyethylene glycol (PEG) hydrogel with glucosamine and then encapsulated human bone mesenchymal stem cells (hBMSCs) in the hydrogel to induce the differentiation of hBMSCs into chondrocytes in three-dimensional culture. The GA-modified PEG hydrogels promoted the chondrogenesis of hBMSCs, particularly in the concentration of 5mM and 10mM. The subcutaneous transplantation of 10mM GA-modified hydrogels with hBMSCs formed cartilage-like blocks in vivo for 8weeks. Importantly, with glucosamine increase, the modified hydrogels down-regulated the fibrosis and hypertrophic cartilage markers in protein level. Therefore, glucosamine modified PEG hydrogels facilitated the chondrogenesis of hBMSCs, which might represent a new method for cartilage repair using a tissue-engineering approach.

[Measurement of components of the phospholipid of the surfactant in irrigating fluid from the nasopharynx of patients with chronic sinusitis].

OBJECTIVE: To investigate the effect of chronic sinusitis on components of the phospholipid of nasopharyngeal surfactant, and to study biochemical component of phospholipid of surface active substance. METHOD: The concentrations of surfactant in nasopharyngeal irrigating fluid were implemented in normal controls and patients with chronic sinusitis. Components of phospholipid such as Phosphatidylserine, Phosphatidylethanolamine, Phosphatidylcholine and Sphingophospholipid were measured by the high-performance liquid chromatograph. RESULT: Results showed as follows (1) There was surfactant in nasopharynx. 4 compositions of phospholipid could be measured. (2) Compared with controls, Phosphatidylserine signficantly decreased in patients with chronic sinusitis (P < 0.05). (3) Only Phosphatidylserine signficantly decreased between sinusitis III stages and controls (P < 0.05). The rests had no signficant difference between chronic sinusitis' stages and controls, and among stages. But as the chronic sinusitis' stages proceeded, proportion of Phosphatidylserine may decreased. CONCLUSION: (1) There is surfactant in nasopharynx, nasopharyngeal surfactant is made of Phosphatidylserine, Phosphatidylethanolamine, Phosphatidylcholine and Sphingophospholipid. The proportion of Phosphatidylcholine shows most, and determines biochemical effect of nasopharyngeal surfactant. (2) chronic sinusitis may cause decrease of some components of nasopharyngeal surfactant. (3) As the chronic sinusitis' stages proceed, the proportion of some phospholipids progressively decrease. Which, above assessed, may cause the change of surfactant in eustachian tube, and cause dysfunction of middle ear and eustachian tube.