Examination of muscular pain when using an innovative smartphone app for adults.

BACKGROUND: Smartphones are very convenient and accessible communication devices. Smartphone usage over long durations with poor posture can lead to musculoskeletal pain in adult users. OBJECTIVE: To compare pain in the neck, shoulder, upper back, lower back, arm, hand, and eye regions. METHODS: Thirty-five asymptomatic adults aged 18-25 years were divided into two groups: 1. use of an innovative smartphone app for the promotion of ergonomic behaviour (app use) and 2. no use of the innovative smartphone app (no app use). Participants sat upright, holding a smartphone with two hands, eyes 30-40 cm away from the screen, with frequent breaks consisting of stretching the neck and hand muscles while resting the eyes. The task involved taking part in online social networking for a duration of 45 minutes. A body pain chart and the visual analog scale (VAS) were used to evaluate the location and severity of pain. RESULTS: Pain in the neck, shoulder, upper back, arm, and hand regions in the "app use" condition were significantly lower than in the "no app use" condition at 15, 30, and 45 min (p-value<0.05). However, there were negligible differences between the two groups for eye pain, and lower back pain. CONCLUSION: Pain in the neck, shoulder, upper back, and arm regions in adult users in the "app use" condition was less than in the "no app use" condition. We would recommend that adults use the innovative smartphone app to prevent the risk of musculoskeletal pain potentially caused by smartphone usage.

HeLa cell transfection using a novel sonoporation system.

Sonoporation has been shown to have an important role in biotechnology for gene therapy and drug delivery. This paper presents a novel microfluidic sonoporation system that achieves high rates of cell transfection and cell viability by operating the sonoporation chamber at resonance. The paper presents a theoretical analysis of the resonant sonoporation chamber design, which achieves sonoporation by forming an ultrasonic standing wave across the chamber. A piezoelectric transducer (PZT 26) is used to generate the ultrasound and the different material thicknesses have been identified to give a chamber resonance at 980 kHz. The efficiency of the sonoporation system was determined experimentally under a range of sonoporation conditions and different exposures time (5, 10, 15, and 20 s, respectively) using HeLa cells and plasmid (peGFP-N1). The experimental results achieve a cell transfection efficiency of 68.9% (analysis of variance, ANOVA, p < 0.05) at the resonant frequency of 980 kHz at 100 V(p-p) (19.5 MPa) with a cell viability of 77% after 10 s of insonication.