Health Effects of E Cigarettes Kansas Health Institute E liquids and vanillin flavoring disrupts retinoic acid signaling and causes craniofacial defects in Xenopus embryos ScienceDirect Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine dependent manner Thorax E cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells PLOS One Thirdhand Vapor from E cigarettes Damages the Lungs of Mice Thirdhand Smoke Resource Center