RESUMEN
Purpose: To explore the effect of coronavirus disease 2019 (COVID-19) infection on neonates in plateau regions. Methods: Cases of newborns born to pregnant women infected with COVID-19 who received prenatal care or treatment at the Women and Children's Hospital of the Tibet Autonomous Region and the Lhasa People's Hospital between January 2020 and December 2022 (infected group) and newborns born to healthy pregnant women (non-infected group) who were included by age, underlying disease and length of hospital stay were retrospectively collected. According to the inclusion and exclusion criteria, 381 patients in the infected group and 314 patients in the non-infected group were included in the study. Results: The results of multivariate analysis showed that admission to the neonatal intensive care unit (OR = 3.342, 95% CI = 1.564-6.764), shortness of breath (OR = 2.853, 95% CI = 1.789-3.154), irregular breathing (OR = 2.465, 95% CI = 1.879-4.112) and neonatal jaundice (OR = 2.324, 95% CI = 1.989-2.445) were the factors influencing the low Apgar scores of neonates in the infected group (all P < 0.05). Conclusion: Neonates born to pregnant women infected with COVID-19 had lower Apgar scores and higher incidences of complications, such as shortness of breath, groaning, irregular breathing and neonatal jaundice, than newborns born to pregnant women not infected with COVID-19.
RESUMEN
An unconventional inchworm actuator for precision positioning based on piezoelectric (PZT) actuation and electrorheological fluids (ERFs) control technology is presented. The actuator consists of actuation unit (PZT stack pump), fluid control unit (ERFs valve), and execution unit (hydraulic actuator). In view of smaller deformation of PZT stack, a new structure is designed for actuation unit, which integrates the advantages of two modes (namely, diaphragm type and piston type) of the volume changing of pump chamber. In order to improve the static shear yield strength of ERFs, a composite ERFs valve is designed, which adopts the series-parallel plate compound structure. The prototype of the inchworm actuator has been designed and manufactured in the lab. Systematic test results indicate that the displacement resolution of the unconventional inchworm actuator reaches 0.038 µm, and the maximum driving force and velocity are 42 N, 14.8 mm/s, respectively. The optimal working frequency for the maximum driving velocity is 120 Hz. The complete research and development processes further confirm the feasibility of developing a new type of inchworm actuator with high performance based on PZT actuation and ERFs control technology, which provides a reference for the future development of a new type of actuator.
