Fabrication of Biodegradable Poly(caprolactone) Spherical-Microcarriers for Arterial Embolization.

This study aimed to develop emulsification assisted with ultrasonic atomization (EUA) to make embolic biodegradable poly(caprolactone) (PCL) spherical-microcarriers with uniform particle size for mass production which was used to cure hepatocellular carcinoma, because this kind of embolic drugs is expensive at the current market due to their complex manufacturing process. The embolic spherical-microcarriers with sustained-releasing therapeutic agents can shrink an unresectable tumor into a respectable size. Through high frequency vibrating surface on the ultrasonic atomizer nozzle, the thin liquid film for PCL oil-phase solution was broken into the uniform PCL microdroplets (particle sizes are from 20 to 55 µm) with less medicine loss. To determine the optimal parameters to make PCL microcarriers, the ultrasonic module parameters including the concentration of PCL solution, vibrating amplitude of atomizer, feeding rate of PCL oil-phase solution and collection distance on the particle size of microdroplets were analyzed. Besides, a vertical circulation flow field of aqueous-phase poly(vinyl alcohol) (PVA) solution was created to enhance the separation of the microdroplets and increase the production of the PCL microcarriers, and about 8~11 wt% of PVA solution with high stable dispersion property was used to effectively improve the yield rate of PCL spherical-microcarriers (89.8~98.2 wt%). The final particle size of PCL microcarriers was ca. 5-18 µm, indicating an about 25-50% volume shrinkage from microdroplets to solid spherical-microcarriers.

A Misalignment Optical Guiding Module for Power Generation Enhancement of Fixed-Type Photovoltaic Systems.

: This study presents a misalignment light-guiding module to increase the effectiveness of absorbing light. For a general fixed-type photovoltaic (PV) panel, the misalignment light decreases the efficiency of the system. A solar tracking system was installed for obtaining higher power generation. However, the cost of the PV system and maintenance was 5-10 times higher than the general type. In this study, this module is composed of an array of misalignment light-guiding units that consist of a non-axisymmetric compound parabolic curve (NACPC) and a freeform surface collimator. The NACPC efficiently collects the misalignment light within ±30° and guides the light to the collimator. The light has a better uniformity and smaller angle at the exit aperture. The simulation results show that the optical efficiency of the unit was above 70% when the misalignment angle was smaller than 20°. The experimental results show that the power generation of the light-guiding unit was 1.8 times higher than the naked PV panel.