Electronic control of elastomeric microfluidic circuits with shape memory actuators

Recently, sophisticated fluidic circuits with hundreds of independent valves have been built by using multi-layer soft-lithography to mold elastomers. However, this shrinking of microfluidic circuits has not been matched by a corresponding miniaturization of the actuation and interfacing elements that control the circuits; while the fluidic circuits are small (~10–100 micron wide channels), the Medusa's head-like interface, consisting of external pneumatic solenoids and tubing or mechanical pins to control each independent valve, is larger by one to four orders of magnitude (mm to cm). Consequently, the dream of using large scale integration in microfluidics for portable, high throughput applications has been stymied. By combining multi-layer soft-lithography with shape memory alloys (SMA), we demonstrate electronically activated microfluidic components such as valves, pumps, latches and multiplexers, that are assembled on printed circuit boards (PCBs). Thus, high density, electronically controlled microfluidic chips can be integrated alongside standard opto-electronic components on a PCB. Furthermore, we introduce the idea of microfluidic states, which are combinations of valve states, and analogous to instruction sets of integrated circuit (IC) microprocessors. Microfluidic states may be represented in hardware or software, and we propose a control architecture that results in logarithmic reduction of external control lines. These developments bring us closer to building microfluidic circuits that resemble electronic ICs both physically, as well as in their abstract model

Fear, risk perception, and engagement in preventive behaviors for COVID-19 during nationwide lockdown in Nepal

The world has faced huge negative effects from the COVID-19 pandemic between early 2020 and late 2021. Each country has implemented a range of preventive measures to minimize the risk during the COVID-19 pandemic. This study assessed the COVID-19-related fear, risk perception, and preventative behavior during the nationwide lockdown due to COVID-19 in Nepal. In a cross-sectional study, conducted in mid-2021 during the nationwide lockdown in Nepal, a total of 1484 individuals completed measures on fear of COVID-19, COVID-19 risk perception, and preventive behavior. A multiple linear regression analysis was used to identify factors associated with COVID-19 fear. The results revealed significant differences in the fear of COVID-19 in association with the perceived risk of COVID-19 and preventive behaviors. Age, risk perception, preventive behavior, and poor health status were significantly positively related to fear of COVID-19. Perceived risk and preventive behaviors uniquely predicted fear of COVID-19 over and above the effects of socio-demographic variables. Being female and unmarried were the significant factors associated with fear of COVID-19 among study respondents. Higher risk perception, poor health status, and being female were strong factors of increased fear of COVID-19. Targeted interventions are essential to integrate community-level mental health care for COVID-19 resilience