Despite the prevalence of the phenomena of peer victimization and bystander behaviors, little data has generated to describe their relationships and risk factors. In this paper, a self-administered survey using a cross-sectional cluster-random sampling method in a sample of 5450 participants (2734 girls and 2716 boys) between 4th and 11th grades was conducted at six schools (two primary schools and four middle schools) located in Shantou, China. Self-reported peer victimization, bystander behaviors and information regarding parents’ risky behaviors and individual behavioral factors were collected. Multinomial logistic regression analysis was applied to evaluate risk factors affecting peer victimization and bystander behaviors. The results indicated that urban participants were more likely to become bullying victims but less likely to become passive bystanders. Contrarily, bullying victimization was related to the increasing of passive bystander behaviors. Father drinking and mother smoking as independent factors were risk factors for peer victimization. Participants who were smoking or drinking had a tendency to be involved in both peer victimization and passive bystander behaviors. This study suggested that bystander behaviors, victims’ and parents’ educations play a more important role in peer victimization than previously thought.

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Pressure sensors are a promising design paradigm for wearable devices required to interact gently with the environment. To enable flexible sensors to respond intelligently to the surroundings, microstructures for subtle pressure and force waveform detection are needed. Here, a self‐adaptive pressure sensor is reported in which graphene‐based flakes adhere to the melamine sponge backbones forming hierarchical structures and exhibiting high‐pressure resolution. Under a high preload pressure of 100 kPa, the pressure sensor demonstrates a high‐pressure resolution ability of ≈1‰. The self‐adaptive microstructure change and mechanical behavior are observed simultaneously and dynamically using in situ electron microscopy. The high‐pressure resolution of the pressure sensor enables it to monitor subtle human ballistocardiogram signals, which demonstrates excellent potential in multifarious applications of human motion detection and health monitoring.

Hydrogels are considered as promising materials in developing next-generation wearable sensors due to their intrinsic biocompatibility and low Young's modulus. However, there are few reports on their breathability which is very important for wear comfortability of wearable sensors. Here graphene-based hydrogel is presented with regular pores using microneedles as templates endowing them with excellent breathability (water vapor transmitting rate 2.8 kg d -1 m -2 ), which is near ten times that of human skin (water vapor transmitting rate less than 0.3 kg d -1 m -2 ). A high-performance strain sensor based on this breathable hydrogel is developed. This sensor not only possesses high sensitivity but also has an excellent linearity with strain ranging from 0% to 110%. Based on these performances, this sensor can be applied in monitoring various joint movements and muscle movements. Moreover, it can achieve barrier-free communication through Morse code.