Reduced Graphene Oxide/Polyelectrolyte Multilayers for Fast Resistive Humidity Sensing.

Fast humidity sensors are of interest due to their potential application in new sensing technologies such as wearable personal healthcare and environment sensing devices. However, the realization of rapid response/recovery humidity sensors remains challenging primarily due to the sluggish adsorption/desorption of water molecules, which particularly impacts the response/recovery times. Moreover, another key factor for fast humidity sensing, namely the attainment of equal response and recovery times, has often been neglected. Herein, the layer-by-layer (LbL) assembly of a reduced graphene oxide (rGO)/polyelectrolyte is demonstrated for application in fast humidity sensors. The resulting sensors exhibit fast response and recovery times of 0.75 and 0.85 s (corresponding to times per RH range of 0.24 and 0.27 s RH-1, respectively), providing a difference of only 0.1 s (corresponding to 0.03 s RH-1). This performance exceeds that of the majority of previously reported graphene oxide (GO)- or rGO-based humidity sensors. In addition, the polyelectrolyte deposition time is shown to be key to controlling the humidity sensing kinetics. The as-developed rapid sensing system is expected to provide useful guidance for the tailorable design of fast humidity sensors.

Vaccine storage practices and the effects of education in some private medical institutions.

OBJECTIVES: Although vaccination rates have increased, problems still remain in the storage and handling of vaccines. This study focused on inspecting actual vaccine storage status and awareness, and comparing them before and after education was provided. METHODS: In the primary inspection, a status survey checklist was completed by visual inspection. A questionnaire on the awareness of proper vaccine storage and handling was also administered to vaccine administrators in private medical institutions in 4 regions in Gyeongsangbuk-province. One-on-one education was then carried out, and our self-produced manual on safe vaccine storage and management methods was provided. In the secondary inspection, the investigators visited the same medical institutions and used the same questionnaire and checklist used during the primary inspection. The results before and after education were compared, by treating each appropriate answer as 1 point. RESULTS: The average checklists score was 9.74 (out of 15 points), which increased significantly after education was provided (by 0.84, p<0.001). The participants demonstrated improved practices in recording storage temperatures (p=0.016), storing vaccines in the center of the refrigerator (p=0.004), storing vaccines with other medication and non-medical items (p=0.031) after education. The average score calculated from the questionnaires was 10.48 (out of 14 points), which increased after education (by 1.03, p<0.001). CONCLUSIONS: This study suggests that vaccine storage practices and awareness are inadequate, but can be partially improved by providing relevant education. Repetitive education and policy-making are required to store vaccines safely because one-off education and unenforced guidelines offer limited efficacy.