Breastfeeding is a complex process where the infant utilizes two forms of pressure during suckling, vacuum and compression. Infant applied compression, or positive oral pressure, to the breast has not been previously studied in vivo. The goal of this study is to use a methodology to capture the positive oral pressure values exerted by infants' maxilla (upper jaw) and mandible (lower jaw) on the breast areola during breastfeeding. In this study, the positive and negative (vacuum) pressure values are obtained simultaneously on six lactating mothers. Parallel to the pressure data measurements, ultrasound images are captured and processed to reveal the nipple deformations and the displacements of infants' tongues and jaw movements during breastfeeding. Motivated by the significant differences in composition between the tissue of the breast and the nipple–areola complex, the strain ratio values of the lactating nipples are obtained using these deformation measurements along with pre- and postfeed three-dimensional (3D) scans of the breast. The findings show an oscillatory positive pressure profile on the breast under both maxilla and mandible, which differs from clinical indications that only the mandible of an infant moves during breastfeeding. The strain ratio varies between mothers, which indicates volume changes in the nipple during feeding and suggests that previous assumptions regarding strain ratio for nonlactating breasts will not accurately apply to breast tissue during lactation.

Objective: This work introduces a bio-inspired breastfeeding simulator (BIBS), an experimental apparatus that mimics infant oral behavior and milk extraction, with the application of studying the breastfeeding mechanism in vitro . Methods: The construction of the apparatus follows a clinical study by the authors that collects measurements of natural intra-oral vacuum, the pressure from infant's jaw, tongue and upper palate, as well as nipple deformation on the breast areola area. The infant feeding mechanism simulator consists of a self-programmed vacuum pump assembly simulating the infant's oral vacuum, two linear actuators mimicking the oral compressive forces, and a motor-driven gear representing the tongue motion. A flexible, transparent and tissue-like breast phantom with bifurcated milk duct structure is designed and developed to work as the lactating human breast model. Bifurcated ducts are connected with a four-outlet manifold under a reservoir filled with milk-mimicking liquid. Piezoelectric sensors and a CCD (charge-coupled device) camera are used to record and measure the in vitro dynamics of the apparatus. Results: All mechanisms are successfully coordinated to mimic the infant's feeding mechanism. Suckling frequency and pressure values on the breast phantom from the experimental apparatus are in good agreement with the clinical data. Also, the change in nipple deformation captured by BIBS matches with those from in vivo clinical ultrasound images. Significance: The fully-developed breastfeeding simulator provides a powerful tool for understanding the bio-mechanics of breastfeeding and formulates a foundation for future breastfeeding device development.

In many industrial applications, a permeable mesh (porous screen) is used to control the unsteady (most commonly vortex) flows. Vortex flows are known to display intriguing behavior while propagating through porous screens. This numerical study aims to investigate the effects of physical properties such as porosity, Reynolds number, inlet flow dimension, and distance to the screen on the flow behavior. The simulation model includes a piston-cylinder vortex ring generator and a permeable mesh constructed by evenly arranged rods. Two methods of user-defined function and moving mesh have been applied to model the vortex ring generation. The results show the formation, evolution, and characteristics of the vortical rings under various conditions. The results for vorticity contours and the kinetic energy dissipation indicate that the physical properties alter the flow behavior in various ways while propagating through the porous screens. The numerical model, cross-validated with the experimental results, provides a better understanding of the fluid–solid interactions of vortex flows and porous screens.

Due to the global pandemic in 2020, rehabilitation services had to adapt to virtual care to meet the needs of patients with a diversity of upper extremity disorders and injuries, from simple fingertip injuries to replanted extremities, while mitigating the spread of COVID-19. For patients who require occupational therapy in their rehabilitation, teleoperated robotic care can fulfill this need. Moreover, some clinical studies show that incorporating the active intention of patients into rehabilitation training enhances the effectiveness of therapies. This research aims to develop a bilateral impedance controller with a Franka Emika 7DOF (degree-of-freedom) articulated robot using matlab, facilitating upper limb occupational therapy. Through this setup, the Franka robot will lead patients through various therapeutic exercises based on their motion intention, such as a pick-and-place exercise. The exercises' efficacy is assessed through evaluations of torque, muscle strength, and jerking performance. During patients' rehabilitation exercises with the Franka robot, we anticipate observing decreased muscle activity alongside a smooth, assist-as-needed (AAN) trajectory. This method will allow a patient to perform complex movements essential for daily activities quicker than traditional occupational therapy.