Iron core gold shell nanoparticles grafted with Methotrexate (MTX) and indocyanine green (ICG) were synthesized for the first time in this study, and preliminarily evaluated for their potential in magnetic hyperthermia treatment. The core-shell Fe@Au nanoparticles were prepared via the microemulsion process and then grafted with MTX and ICG using hydrolyzed poly(styrene-alt-maleic acid) (PSMA) to obtain core-shell Fe@Au-PSMA-ICG/MTX nanoparticles. MTX is an anti-cancer therapeutic, and ICG is a fluorescent dye. XRD, TEM, FTIR and UV-Vis spectrometry were performed to characterize the nanoparticles. The data indicated that the average size of the nanoparticles was 6.4 ± 09 nm and that the Au coating protected the Fe core from oxidation. MTX and ICG were successfully grafted onto the surface of the nanoparticles. Under exposure to high frequency induction waves, the superparamagnetic nanoparticles elevated the temperature of a solution in a few minutes, which suggested the potential for an application in magnetic hyperthermia treatment. The in vitro studies verified that the nanoparticles were biocompatible; nonetheless, the Fe@Au-PSMA-ICG/MTX nanoparticles killed cancer cells (Hep-G2) via the magnetic hyperthermia mechanism and the release of MTX.

No abstract

Many studies have shown that focusing on an intended movement effect that is farther away from the body (distal external focus) results in performance benefits relative to focusing on an effect that is closer to the body (proximal external focus) or focusing on the body itself (internal focus) (see Chua, Jimenez-Diaz, Lewthwaite, Kim, & Wulf, 2021). Furthermore, the advantages of a distal external focus seem to be particularly pronounced in skilled performers (Singh & Wulf, 2020). The present study examined whether such benefits of more distal attentional focus may be associated with enhanced functional variability. Volleyball players (n = 20) performed sixty overhand volleyball serves to a target. Using a within-participants design, the effects of a distal external focus (bullseye), proximal external focus (ball), and an internal focus (hand) were compared. The distal focus condition resulted in significantly higher accuracy scores than did the proximal and internal focus conditions. In addition, uncontrolled manifold analysis showed that functional variability (as measured with the index of synergy) was greatest in the distal focus condition. These findings suggest that a distal external focus on the task goal may enhance movement outcomes by optimizing compensatory coordination of body parts.

The protocol utilized a side-by-side split-belt instrumented treadmill to simulate a trip-like perturbation. Compared to previously published methodologies, this new protocol is focused on delivering the perturbation at a precise timepoint during gait. Programmed treadmill belt acceleration profiles are triggered unilaterally at the instant the tripped leg bears 20-25% of the body weight in early stance phase. The belt acceleration profile starts from a comfortable walking speed, followed by a sudden slowdown, then an acceleration, and finally returning to the comfortable walking speed. The slowdown is meant to simulate the foot obstruction and the acceleration reproduces the leg-torso discoordination and the trunk forward thrust during a trip.

Tripping is a common cause of falls and a focus of many biomechanical investigations. Concerns regarding the precision of delivery of simulated-fall protocols reside in the current biomechanical methodology literature. This study aimed to develop a treadmill-based protocol that generated unanticipated trip-like perturbations during walking with high timing precision. The protocol utilized a side-by-side split-belt instrumented treadmill. Programmed treadmill belt acceleration profiles (two levels of perturbation magnitude) were triggered unilaterally at the instant the tripped leg bore 20% of the body weight. Test-retest reliability of fall responses was examined in 10 participants. Utility was examined as to whether the protocol could differentiate the fall recovery responses and likelihood of falls, estimated using peak trunk flexion angle after perturbation, between young and middle-aged adults (n = 10 per group). Results showed that the perturbations could be precisely and consistently delivered during early stance phases (10–45 milliseconds after initial contact). The protocol elicited excellent reliability of responses in both perturbation magnitudes (ICC = 0.944 and 0.911). Middle-aged adults exhibited significantly greater peak trunk flexion than young adults (p = 0.035), indicating that the current protocol can be utilized in differentiating individuals with different levels of fall risks. The main limitation of the protocol is that perturbations are delivered in stance rather swing phase. This protocol addressed some issues discussed in previous “simulated fall” protocols and may be useful for future fall research and subsequent clinical interventions.