Single-Atom Pt Boosting Electrochemical Nonenzymatic Glucose Sensing on Ni(OH)2/N-Doped Graphene.

Conventional nanomaterials in electrochemical nonenzymatic sensing face huge challenge due to their complex size-, surface-, and composition-dependent catalytic properties and low active site density. In this work, we designed a single-atom Pt supported on Ni(OH)2 nanoplates/nitrogen-doped graphene (Pt1/Ni(OH)2/NG) as the first example for constructing a single-atom catalyst based electrochemical nonenzymatic glucose sensor. The resulting Pt1/Ni(OH)2/NG exhibited a low anode peak potential of 0.48 V and high sensitivity of 220.75 µA mM-1 cm-2 toward glucose, which are 45 mV lower and 12 times higher than those of Ni(OH)2, respectively. The catalyst also showed excellent selectivity for several important interferences, short response time of 4.6 s, and high stability over 4 weeks. Experimental and density functional theory (DFT) calculated results reveal that the improved performance of Pt1/Ni(OH)2/NG could be attributed to stronger binding strength of glucose on single-atom Pt active centers and their surrounding Ni atoms, combined with fast electron transfer ability by the adding of the highly conductive NG. This research sheds light on the applications of SACs in the field of electrochemical nonenzymatic sensing.

Free-Standing N-Doped Porous Carbon Fiber Membrane Derived From Zn-MOF-74: Synthesis and Application as Anode for Sodium-Ion Battery With an Excellent Performance.

It is important to develop new energy storage and conversion technology to mitigate the energy crisis for the sustainable development of human society. In this study, free-standing porous nitrogen-doped carbon fiber (PN-CF) membranes were obtained from the pyrolysis of Zn-MOF-74/polyacrylonitrile (PAN) composite fibers, which were fabricated in situ by an electrospinning technology. The resulting free-standing fibers can be cut into membrane disks and directly used as an anode electrode without the addition of any binder or additive. The PN-CFs showed great reversible capacities of 210 mAh g-1 at a current density of 0.05 A g-1 and excellent cyclic stability of 170.5 mAh g-1 at a current density of 0.2 A g-1 after 600 cycles in sodium ion batteries (SIBs). The improved electrochemical performance of PN-CFs can be attributed to the rich porous structure derived by the incorporation of Zn-MOF-74 and nitrogen doping to promote sodium ion transportation.

[Effect of casein osphopeptide-amorphous calcium phosphate solution in preventing enamel demineralization].

OBJECTIVE: To evaluate the effects of casein osphopeptide-amorphous calcium phosphate (CPP-ACP) in preventing enamel demineralization. METHODS: Enamel blocks were prepared from premolars extracted from orthodontic patients. The specimens were treated for 30 min daily for 7 days with one of the following agents: deionized water (negative control), CPP-ACP paste, and NaF solutions (positive controls) (0.2% and 2%). After the treatments, the specimens were immersed in a demineralizing solution (pH 4.5) for 7 days. The morphology and depth of the lesion were observed using scanning electron microscopy, and the content of Ca, P, Mg in the demineralized enamel was measured by electron probe micro-analyzer. RESULTS: The demineralization rates in all the treatment groups were significantly smaller than those in the control group after 7 days of demineralization. CONCLUSION: The application of CPP-ACP to the enamel surfaces can inhibit enamel demineralization with an equivalent effect to 0.2% NaF.

[Detection of Helicobacter pylori in oral cavity of patients with recurrent aphthous ulcer].

OBJECTIVE: To investigate the association of recurrent aphthous ulcer (RAU) with Helicobacter pylori (Hp) infection and digestive diseases. METHODS: Saliva samples were collected from 82 patients with RAU and 74 healthy volunteers for Hp detection with PCR. RESULTS: The positivity rates of HP differed significantly between RAU patients and healthy volunteers (43.9% vs 16.2%, P<0.001). In the 82 RAU patients, 22 (26.82%) were identified to have gastritis and peptic ulcer, whereas only 7 out of the 74 healthy volunteers (10.45%) had such digestive diseases, showing significant difference between them (P<0.01). CONCLUSION: Hp might in some way associate with RAU, which in turn is associated with an increased incidence of digestive diseases.