Bird song and human speech are learned early in life and for both cases engagement with live social tutors generally leads to better learning outcomes than passive audio-only exposure. Real-world... Show moreBird song and human speech are learned early in life and for both cases engagement with live social tutors generally leads to better learning outcomes than passive audio-only exposure. Real-world tutor-tutee relations are normally not uni- but multimodal and observations suggest that visual cues related to sound production might enhance vocal learning. We tested this hypothesis by pairing appropriate, colour-realistic, high frame-rate videos of a singing adult male zebra finch tutor with song playbacks and presenting these stimuli to juvenile zebra finches (Taeniopygia guttata). Juveniles exposed to song playbacks combined with video presentation of a singing bird approached the stimulus more often and spent more time close to it than juveniles exposed to audio playback only or audio playback combined with pixelated and time-reversed videos. However, higher engagement with the realistic audio-visual stimuli was not predictive of better song learning. Thus, although multimodality increased stimulus engagement and biologically relevant video content was more salient than colour and movement equivalent videos, the higher engagement with the realistic audio-visual stimuli did not lead to enhanced vocal learning. Whether the lack of three-dimensionality of a video tutor and/or the lack of meaningful social interaction make them less suitable for facilitating song learning than audio-visual exposure to a live tutor remains to be tested. Show less
Chen, X.; Jin, R.; Jiang, Q.; Bi, Q.; He, T.; Song, X.; ... ; Nie, Y. 2021
The tumor hypoxic microenvironment not only induces genetic and epigenetic changes in tumor cells, immature vessels formation for oxygen demand, but also compromises the efficiency of therapeutic... Show moreThe tumor hypoxic microenvironment not only induces genetic and epigenetic changes in tumor cells, immature vessels formation for oxygen demand, but also compromises the efficiency of therapeutic interventions. On the other hand, conventional therapeutic approaches which kill tumor cells or destroy tumor blood vessels to block nutrition and oxygen supply usually facilitate even harsher microenvironment. Thus, simultaneously relieving the strained response of tumor cells and blood vessels represents a promising strategy to reverse the adverse tumor hypoxic microenvironment. In the present study, an integrated amphiphilic system (RSCD) is designed based on Angiotensin II receptor blocker candesartan for siRNA delivery against the hypoxia-inducible factor-1 alpha (HIF-1α), aiming at both vascular and cellular "relaxation" to reconstruct a tumor normoxic microenvironment. Both in vitro and in vivo studies have confirmed that the hypoxia-inducible HIF-1α expression is down-regulated by 70% and vascular growth is inhibited by 60%. The "relaxation" therapy enables neovascularization with more complete and organized structures to obviously increase the oxygen level inside tumor, which results in a 50% growth inhibition. Moreover, reconstruction of tumor microenvironment enhances tumor-targeted drug delivery, and significantly improves the chemotherapeutic and photodynamic anticancer treatments. Show less
