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Abstract Antimicrobial surfactants contained in mouthrinse have excellent efficacy, but are not retained on the tooth surface (are rinsed away) due to their low water resistance and thus do not exhibit sustained antibacterial activity. We have developed a new coating method using graphene oxide (GO) that retains the surfactant on the tooth surface even after rinsing with water, thus providing a sustained antibacterial effect. Ultra-thin films of GO and an antimicrobial agent were prepared by (1) applying GO to the substrate surface, drying, and thoroughly rinsing with water to remove excess GO to form an ultrathin film (almost a monolayer, transparent) on the substrate surface, then (2) applying antimicrobial cationic surface active agents (CSAAs) on the GO film to form a composite coating film (GO/CSAA). GO/CSAA formation was verified by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and ζ-potential and contact angle measurements. GO/CSAA was effective at inhibiting the growth of oral pathogens for up to 7 days of storage in water, and antibacterial activity was recovered by reapplication of the CSAA. Antibacterial GO/CSAA films were also formed on a tooth substrate. The results suggest that GO/CSAA coatings are effective in preventing oral infections.

We previously proposed a lithium-ion battery system based on redox reactions between Li2O2 and Li2O by producing a Co-doped Li2O (CDL) cathode. CDL is synthesized by the mechanochemical method with Li2O and Co-dopant as the source materials in a planetary ball mill. Here, we aim to reveal the relation between the planetary ball milling conditions (the number and size of media balls, rotational speed, and processing time) and the characteristics of CDL. Moreover, we intend to optimize these conditions to improve the performance of CDL. While CDL decomposes into Li2O and LiCoO2 when the impact energy from the collision of balls is too high, we successfully suppress the decomposition reaction of CDL to obtain CDL with higher Co-doping levels than that previously reported by optimizing synthetic conditions. The CDL prepared under optimal conditions delivers a specific capacity of 450 mAh g-1 and exhibits stable discharge behavior for at least 30 cycles. [ABSTRACT FROM AUTHOR]

Uniform Cu2Sn1-xZnxS3 (x=0-0.2) nanoparticles (NPs) with a characteristic size of about 40 nm were chemically synthesized. The primary crystal phase of the NPs was wurtzite (WZ) with a mean crystalline size of about 20 nm. The NPs were sintered to form nanostructured pellets with different compositions preserving the composition and grain size of the original NPs by the pulse electric current sintering technique. The pellets had a zinc blende (ZB) structure with a residual WZ phase, and the mean crystalline size was found to remain virtually unchanged for all pellets. Among all samples, the pellets of Cu2Sn0.95Zn0.05S3 and Cu2Sn0.85Zn0.15S3 exhibited the highest ZT value (0.37 at 670K) which is 10 times higher than that of a non-nanostructured Cu2SnS3 bulk crystal thanks to effective phonon scattering by nanograins, the phase-pure ZB crystal structure, and the increase in hole carrier density by Zn doping. [ABSTRACT FROM AUTHOR]

A Co-doped Li2O (CDL) was synthesized using a planetary ball mill and examined as a cathode material for lithium-ion batteries. When vinylene carbonate, which is often employed as an additive in an electrolyte, was used not only as an additive in the electrolyte but also as a treatment agent for CDL, the specific capacity of CDL was greatly enhanced and the charge-discharge cycles with specific charging and discharging capacities of 400 mAh/g could be repeated for more than 50 times. Co K-edge XANES spectroscopy and quantitative analysis of peroxide species revealed that the redox reactions of cobalt ions, formation/neutralization of O 2p electron holes, and generation/annihilation of peroxide species occurred during the charge-discharge process. [ABSTRACT FROM AUTHOR]