We use a green sputtering technique to deposit a Pt/Cu alloy target on liquid polyethylene glycol (PEG) to obtain well-dispersed and stable Pt29Cu71 alloy nanoparticles (NPs). The effects of sputtering current, rotation speed of the stirrer, sputtering time, sputtering period, and temperature of PEG on the particle size are studied systematically. Our key results demonstrate that the aggregation and growth of Pt/Cu alloy NPs occurred at the surface as well as inside the liquid polymer after the particles landed on the liquid surface. According to particle size analysis, a low sputtering current, high rotation speed for the stirrer, short sputtering period, and short sputtering time are found to be favorable for producing small-sized single crystalline alloy NPs. On the other hand, varying the temperature of the liquid PEG does not have any significant impact on the particle size. Thus, our findings shed light on controlling NP growth using the newly developed green sputtering deposition technique.

In-situ filament observations were carried out on the Cu/MoOx/TiN resistive random access memory (ReRAM) by using transmission electron microscopy. Multiple positive and negative I-V cycles were investigated. Clear set-reset bipolar switch corresponding to the characteristics of conventional ReRAM devices was recognized. Filament grew from TiN to Cu in the set cycle and shrank from TiN to Cu in the reset cycle. However, there was no clear contrast change in the image at the switching moment, and thus, switching is thought to occur in a local region of the filament. When the current was large at reset, the filament shrank much, and its position tended to change.

Pt/Au alloy nanoparticles (NPs) in a wide composition range have been synthesized by room-temperature simultaneous sputter deposition from two independent magnetron sources onto liquid PEG (MW = 600). The prepared NPs were alloyed with the face-centered cubic (fcc) structure. In addition, the particle sizes, composition, and shape are strongly correlated but can be tailored by an appropriate variation of the sputtering parameters. No individual particle but large agglomerates with partial alloy structure formed at Pt content of less than 16 atom %. Highly dispersed NPs with no agglomeration were observed in PEG when the quantity of Pt is more than 26 atom %. On the other hand, a small amount of Pt could terminate the agglomeration of Au when sputtering on the grids for transmission electron microscope observation. Our experiment and computer simulation carried out by two different methods indicate that the composition-dependent particle size of Pt/Au can be explained by the atomic concentration, formation energy of the cluster, and interaction between different metal atoms and the PEG molecule.

Several species of scavenger receptors have so far been identified. However, it remains unclear which receptors are more crucial for the foam cell formation and progression. In the present study, we compared five major scavenger receptors (SR-A, CD36, CLA-1, CD68, and LOX-1) in their levels of expression at the different stages of foam cells derived from THP-1 cells. The expression of all scavenger receptors examined was up-regulated by the stimulation with TPA for 48 hours, despite the expressions of SR-A, CD36 and LOX-1 being very low before the treatment with TPA. Four to 7 days after the removal of TPA, the levels of CD36, CLA-1 and CD68 were increased significantly. In contrast, the expression of SR-A was suppressed significantly, and no change was observed in that of LOX-1. Furthermore, when the transformed macrophages were incubated with oxidized LDL, in which the uptake of [3H] cholesteryl oleoyl ether-labeled OxLDL was linear up to 7 days after the addition of OxLDL, the expression of CD36, CLA-1 and CD68 were greatly enhanced. This enhancement was more prominent than that without oxidized LDL, and the enhancement was sustained throughout the experimental period. On the other hand, SR-A was not up-regulated, and LOX-1 was down-regulated. We thus propose that CD36, CLA-1 and CD68, but not SR-A and LOX-1, may play crucial roles in the progression of macrophages to foam cells, which is a key step for the initiation of atherosclerosis.

Active feedback control was applied to suppress oscillations in thermocapillary convection in a half-zone liquid bridge. The experiment is on a unit-aspect-ratio liquid bridge where the most unstable azimuthal mode has wavenumber 2 when control is absent. Active control was realized by locally modifying the surface temperature using the local temperature measured at different locations fed back through a simple control law. The performance of the control process was quantified by analysing local temperature signals, and the flow structure was simultaneously identified by flow visualization. With optimal placement of sensors and heaters, proportional control can raise the critical Marangoni number by more than 40%. The amplitude of the oscillation can be suppressed to less than 30% of the initial value for a wide range of Marangoni number, up to 90% of the critical value. The proportional control was tested for a period-doubling state and it stabilized the oscillation to a periodic state. Weakly nonlinear control was applied by adding a cubic term to the control law to improve the performance of the control and alter the bifurcation characteristics.