Study of a Multiple Responses, High Deformation, and Programmable PLA-PPC/PVA-PDA Actuator.

The intelligent response actuators based on bilayer polymer can deform under the stimulation of temperature, humidity, light, and other external environment, which is the focus of research. However, achieving multiple responses, high deformation, and programmability is still one of the challenges for these actuators. Herein, a nondetachable bilayer structure, polylactic acid-polypropylene carbonate/polyvinyl alcohol-polydopamine (PLA-PPC/PVA-PDA) multiresponse programmable actuator is prepared by a simple scraping film method. Using PLA-PPC as the solvent-driven response layer, the effects of length, thickness, shape, and solvent vapor on the deformation of PLA-PPC/PVA-PDA actuators are studied. Among them, the high curvature of the film stimulated by ethyl acetate (EA) solution is 29.85 cm-1 . Using PVA-PDA as the response layer to water molecules and infrared (IR) light, the bilayer film shows excellent curling performance. Moreover, the dynamic processes of human clothing and biomimetic squid under solvent stimulation, the picture rolling motion under water molecule stimulation, the biomimetic flower blooming and merging under the synergistic of water molecules and IR light, and the deformation process of biomimetic mimosa under the competition between water molecules and IR light are simulated, which broadens the road for the development of intelligent driving materials.

A rare case of residual root myiasis caused by Clogmia albipunctata larvae (Diptera: Psychodidae).

BACKGROUND: Dental injury caused by caries and trauma is the main cause of residual roots. Food trapped in the residual roots is difficult to clean. If the residual roots are not treated and cared for in time, flies can take advantage as soon as hygiene slips. Here, we present a rare case of human residual root myiasis caused by Clogmia albipunctata larvae, never previously reported. CASE PRESENTATION: A 26-year-old lady found two active, living larvae in her mouth while brushing her teeth. She did not present with fever, pain and any uncomfortable oral feeling. The intraoral examination revealed the right second mandibular molar was severely damaged as a result of caries, leaving a residual tooth root. The mucosa above it was mildly erythematous and edematous. No larvae and no inflamed gums were observed in her mouth. When normal saline was used to flush the area of the residual root with a syringe, four larvae appeared from the residual root. The larvae were observed by naked eye and under a light microscope. They were identified as the mature stage larvae of Clogmia albipunctata. Because the patient was in lactation, medication was not recommended. Treatment included the removal of all visible larvae followed by flushing the residual root with normal saline three times a day. The patient was followed-up weekly for one month. No more larvae were found and the erythematous and edematous mucosa healed completely. CONCLUSIONS: The existence of a residual root can result in residual root myiasis. Myiasis caused by Clogmia albipunctata larvae or other fly larvae should be considered in cases of residual root infection.