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Nanoparticles (NPs) have been recognized as both useful tools and potentially toxic materials in various industrial and medicinal fields. Previously, we found that zinc oxide (ZnO) NPs that are neurotoxic to human dopaminergic neuroblastoma SH-SY5Y cells are mediated by lipoxygenase (LOX), not cyclooxygenase-2 (COX-2). Here, we examined whether human bone marrow-derived mesenchymal stem cells (MSCs), which are different from neuroblastoma cells, might exhibit COX-2- and/or LOX-dependent cytotoxicity of ZnO NPs. Additionally, changes in annexin V expression, caspase-3/7 activity, and mitochondrial membrane potential (MMP) induced by ZnO NPs and ZnO were compared at 12 hr and 24 hr after exposure using flow cytometry. Cytotoxicity was measured based on lactate dehydrogenase activity and confirmed by trypan blue staining. Rescue studies were executed using zinc or iron chelators. ZnO NPs and ZnO showed similar dose-dependent and significant cytotoxic effects at concentrations ≥ 15 μg/mL, in accordance with annexin V expression, caspase-3/7 activity, and MMP results. Human MSCs exhibited both COX-2 and LOX-mediated cytotoxicity after exposure to ZnO NPs, which was different from human neuroblastoma cells. Zinc and iron chelators significantly attenuated ZnO NPs-induced toxicity. Conclusively, these results suggest that ZnO NPs exhibit both COX-2- and LOX-mediated apoptosis by the participation of mitochondrial dysfunction in human MSC cultures.

Ball-milling and subsequent microwave heating processes have been applied to synthesize VBO 3 –C composite. The samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, inductively coupled plasma mass spectroscopy, and electrochemical methods. The VBO 3 –C composite was successfully prepared after 30 min ball-milling and 13 min microwave heating. The synthesized VBO 3 –C composite was composed of well crystallized VBO 3 particles with well dispersed amorphous carbon and exhibited higher reversible capacity (625 mAh g −1 ) and improved cyclic performance than those in previous study.

The influence of substrate morphology and ageing on the charge–discharge performance of a Sn–Ni alloy anode electrodeposited on a Cu substrate are examined. The Sn–Ni alloy (Sn 82 at.%–Ni 18 at.% anode) shows a high capacity of around 480 mAh g−1 up to 12 cycles, but its capacity rapidly fades with cycling. The initial capacity and the cyclic properties of the alloy electrode are significantly improved when the surface morphology of the Cu substrate is changed from smooth-type to nodule-type. Optimized ageing treatment leads to further enhancement in the charge–discharge performance of the anode. The increase in the capacity and better cyclic properties are attributed to stronger adhesion between the Si–Ni anode and the Cu substrate. This is induced by inter-locking of the nodule-type Cu substrate and a buffering effect of Cu–Sn intermetallic compounds formed during ageing.

Lithium iron phosphate–carbon (LiFePO 4 –C) composites with various amounts of Fe 2 P are synthesized by ball-milling coupled with microwave heating to serve as cathodes for lithium-ion batteries. LiFePO 4 –C in which Fe 2 P is restrained below a critical concentration gives as very high discharge capacity of 165 mAh g −1 , excellent rate capability (85.4% C /50-rate discharge capacity at 2 C ) and stable cyclic retention for 250 cycles. Above the critical concentration however, electrochemical performance deterioated. Analysis and debate, based on a comparison of the physical and electrochemical properties among LiFePO 4 –C composites with the variation of Fe 2 P, proceeded to the conclusion that below the critical concentration, Fe 2 P enhanced the conductivity of LiFePO 4 –C, whereas above the critical concentration, it blocked the one-dimensional Li + pathways in LiFePO 4 and might hinder Li + movement in LiFePO 4 . Therefore, in order to obtain a LiFePO 4 –C composite that enhances electrochemical performance, it is concluded that the amount of Fe 2 P should be carefully controlled below its critical concentration.

A very simple and rapid method for synthesizing LiFePO 4 -C composite has been developed by vibrant type ball-milling for 30 min and microwave heating for 2–4 min. X-ray diffraction and Mossbauer spectroscopy verify that well-crystallized LiFePO 4 without Fe 3+ impurities is obtained. From laser particle size analysis and transmission electron microscopy, it is confirmed that a LiFePO 4 -C composite with fine and uniform particle size (mean particle size ≤0.640 μm, D75 in volume distribution ≤0.592 μm) and with extremely uniform carbon distribution is prepared by vibrant type ball-milling and microwave heating. The LiFePO 4 -C delivers a high initial discharge capacity of 161 mAh g −1 at C/10 and shows very stable cycling behaviour.

The effects of ball-milling on Li insertion into multi-walled carbon nanotubes (MWNTs) are presented. The MWNTs are synthesized on supported catalysts by thermal chemical vapour deposition, purified, and mechanically ball-milled by the high energy ball-milling. The purified MWNTs and the ball-milled MWNTs were electrochemically inserted with Li. Structural and chemical modifications in the ball-milled MWNTs change the insertion–extraction properties of Li ions into/from the ball-milled MWNTs. The reversible capacity ( C rev ) increases with increasing ball-milling time, namely, from 351 mAh g −1 (Li 0.9 C 6 ) for the purified MWNTs to 641 mAh g −1 (Li 1.7 C 6 ) for the ball-milled MWNTs. The undesirable irreversible capacity ( C irr ) decreases continuously with increase in the ball-milling time, namely, from 1012 mAh g −1 (Li 2.7 C 6 ) for the purified MWNTs to 518 mAh g −1 (Li 1.4 C 6 ) for the ball-milled MWNTs. The decrease in C irr of the ball-milled samples results in an increase in the coulombic efficiency from 25% for the purified samples to 50% for the ball-milled samples. In addition, the ball-milled samples maintain a more stable capacity than the purified samples during charge–discharge cycling.