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1.
Molecules ; 24(7)2019 Mar 27.
Article in English | MEDLINE | ID: mdl-30934724

ABSTRACT

A single herb can contain multiple constituents with diverse bioactivities. We found that the extract of Citrus unshiu peel (CUP), induced abnormal vasoconstriction responses on the freshly isolated rat aortic rings in vitro. CUP stimulated the vasoconstriction alone, and it suppressed the phenylephrine-stimulated vasoconstriction. We studied the reasons behind this abnormal vasoconstriction pattern. Major constituents of CUP were determined and evaluated for their vaso-activities. Notably, synephrine, a contractile agonist, and nobiletin, newly identified to have anti-contractile activity co-existed in CUP. Synephrine and nobiletin competitively blocked or activated the same contractile targets resulting in contradicting and abnormal vasoconstriction responses. Accordingly, the vasoconstriction pattern varies significantly depending on the relative contents of synephrine and nobiletin in CUP. Interestingly, this response pattern could be observed with another plant extract, Acorus gramineus Sol. Collectively, we demonstrated that active ingredients with contradicting bioactivities could co-exist in a single plant extract, interact and produce abnormal response patterns in bioassay, which would give an important insight into the interpretation of unusual activity patterns induced by plant extracts.


Subject(s)
Antihypertensive Agents/pharmacology , Citrus/chemistry , Flavones/pharmacology , Plant Extracts/pharmacology , Synephrine/pharmacology , Vasoconstrictor Agents/pharmacology , Antihypertensive Agents/chemistry , Flavones/chemistry , Phytochemicals/chemistry , Phytochemicals/pharmacology , Plant Extracts/chemistry , Synephrine/chemistry , Vasoconstrictor Agents/chemistry
2.
Sci Rep ; 8(1): 10366, 2018 Jul 04.
Article in English | MEDLINE | ID: mdl-29970900

ABSTRACT

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

3.
Sci Rep ; 8(1): 8066, 2018 May 23.
Article in English | MEDLINE | ID: mdl-29795278

ABSTRACT

All-solid-state batteries are considered as one of the attractive alternatives to conventional lithium-ion batteries, due to their intrinsic safe properties benefiting from the use of non-flammable solid electrolytes in ASSBs. However, one of the issues in employing the solid-state electrolyte is the sluggish ion transport kinetics arising from the chemical and physical instability of the interfaces among solid components including electrode material, electrolyte and additive agents. In this work, we investigate the stability of the interface between carbon conductive agents and Li10GeP2S12 in a composite cathode and its effect on the electrochemical performance of ASSBs. It is found that the inclusion of various carbon conductive agents in composite cathode leads to inferior kinetic performance of the cathode despite expectedly enhanced electrical conductivity of the composite. We observe that the poor kinetic performance is attributed to a large interfacial impedance which is gradually developed upon the inclusions of the various carbon conductive agents regardless of their physical differences. The analysis through X-ray Photoelectron Spectroscopy suggests that the carbon additives in the composite cathode stimulate the electrochemical decomposition of LGPS electrolyte degrading its surface during cycling, indicating the large interfacial resistance stems from the undesirable decomposition of the electrolyte at the interface.

4.
J Nanosci Nanotechnol ; 13(12): 7924-31, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24266166

ABSTRACT

A radio frequency (RF) sputtering system is used to coat nano-thick TiO2 layer on the overlithiated layered metal oxide (OLO) electrode. The X-ray diffraction (XRD) and the field emission-scanning electron microscope (FE-SEM) images indicate amorphous TiO2 is coated on the top surface of the electrode with a thickness of approximately 20 nm for the 40 min sputtered sample. The sample sputtered for 40 minutes cycled at 90 mA g(-1) between 2 and 4.8 V versus Li+/Li has 15 mA h g(-1) more specific capacity at 100th cycle than that of the uncoated sample. In the voltage profiles, additional overpotential is unobservable upon sputtering TiO2 in comparison to that of the reference sample. Further analyses by the electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) demonstrate the sputtered sample has less electrolyte decomposition products on the surface than that of the reference sample. Moreover, in the case of sputtering, reduced amount of transition metal and Li2O are deposited on the surface of the counter electrode, Li. In summary, the sputtered TiO2 acts as nano-sized artificial solid electrolyte interface (SEI) layer, which protects the surface of the electrode and improves kinetic properties, leading to improved performance.

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