Youth e-cigarette use has been rising, however U.S. prevalence data are generally reported without disaggregating by individuals' use of other tobacco products. It is not clear how the proportion of youth e-cigarette users naïve to all combustible tobacco is changing. Annual prevalence estimates of ever and current (defined as past 30-day use) tobacco use prevalence by school type are reported using the 2014-2019 National Youth Tobacco Surveys (NYTS) with mutually exclusive categories of e-cigarette, smokeless tobacco, and/or combustible tobacco product use. T-tests were used to compare annual estimates with the preceding year. The annual percent change (APC) for each category from 2014 to 2018 were analyzed using JoinPoint regression. Data for 2019 were reported separately due to the change in survey format from paper to electronic. Current use of only e-cigarettes among HS students who never used combustible tobacco increased significantly from 2014 to 2018 (APC=+42.4%, 95% CI 0.7, 101.3); by 2019, prevalence peaked at 9.2% (95% CI 8.2, 10.2) among never combustible users and 8.3% (95% CI 7.3, 9.3) among former combustible users. This coincided with significant declines in use of only combustible tobacco (APC=-14.5%, 95% CI -18.3, -10.5). Use of only e-cigarettes among US youth with no history of combustible tobacco use has increased substantially over time, even as combustible tobacco use continues to decline. Of the 17.5% (95% CI 15.7, 19.0) of HS students who currently used only e-cigarettes (but not other tobacco) in 2019, more than half have no history of combustible tobacco use.Use of only e-cigarettes among US youth with no history of combustible tobacco use has increased substantially over time, even as combustible tobacco use continues to decline. learn more Of the 17.5% (95% CI 15.7, 19.0) of HS students who currently used only e-cigarettes (but not other tobacco) in 2019, more than half have no history of combustible tobacco use. Data on associations of history of mental illness (HMI) with smoking and vaping in New Zealand (NZ) are lacking. This study examines these associations in university students aged 18-24years. Data came from a 2018 national cross-sectional study of university students and included information on demographic characteristics, smoking, vaping and participant health in the previous 12-months. χ tests compared patterns of smoking and vaping, and logistic regression assessed associations of HMI with smoking and vaping, controlling for age, gender and ethnicity. An HMI was defined as a diagnosis/treatment for depression, anxiety/nervous disorder, or other mental health condition in the previous 12-months. The sample comprised 1293 students 61.3% aged 18-20; 62.8% female; 7.8% Māori, 92.2% non-Māori, and 18.5% reported an HMI. Smoking 49.7% (95% CI 47.0-52.5) reported ever, 10.5% (8.9-12.3) current and 5.0% (3.9-6.4) daily smoking. Vaping 38.7% (36.0-41.4) reported ever, 6.3% (5.1-7.8) current and 1.9% (1.3-2.8) daily vaping. Participants with HMI were significantly more likely to smoke ever (64.9% vs 46.3%, p<.001), current (15.1% vs 9.5%, p=.011) and daily (7.5% vs 4.5%, p=.050), and vape ever (49.4% vs 36.3%, p<.001) and current (9.2% vs 5.7%, p=.044) than participants without HMI. The model containing all predictors of HMI was significant, χ (5, N=1293)=24.09, p<.001. Gender (OR 0.54, (0.4-0.75)), current smoking (OR 1.82, (1.19-2.78)) and current vaping (OR 1.73, (1.02-2.93)) made unique significant contributions to the model. The prevalence of smoking and vaping were significantly higher in students with HMI, and there were strong associations between HMI and smoking and vaping.The prevalence of smoking and vaping were significantly higher in students with HMI, and there were strong associations between HMI and smoking and vaping. Given the low retention and lack of persistent support by traditional tobacco cessation programs, evidence-based smartphone app-supported interventions can be an important tobacco control component. The objective of this systematic review was to identify and evaluate the types of studies that use smartphone apps for interventions in tobacco cessation. We conducted a systematic review of PubMed (1946-2019), EMBASE (1974-2019), and PsycINFO (1806-2019) databases with keywords related to smartphone-supported tobacco cessation. Included articles were required to meet 3 baseline screening criteria 1) be written in English, 2) include an abstract, and 3) be a full, peer-reviewed manuscript. The criteria for the second level of review were 1) primary outcome of tobacco cessation, 2) intervention study, and 3) smartphone app as primary focus of study. Of 1973 eligible manuscripts, 18 met inclusion criteria. Most studies (n=17) recruited adult participants (18+years); one included teens (16+years). Tobacco cessapps. Derivation of pure fetal placental mesenchymal stem/stromal cells (pMSCs) is key to understand their role in placental development. However, isolated pMSCs are often contaminated by maternal-derived decidual MSCs (dMSCs). EGM-2 medium promotes the derivation of term fetal pMSCs, but the extent of first-trimester maternal pMSC contamination remains unclear. Culture media can also affect MSC phenotype. Here, we examined the effects of culture media on maternal pMSC contamination and fetal pMSC phenotype across gestation. pMSCs were derived from first-trimester or term placentae in advanced-DMEM/F12 medium or EGM-2 medium. Proportions of maternal (XX) and fetal (XY) cells in male pMSC cultures were determined by fluorescence in-situ hybridization. pMSC phenotype was analysed by flow cytometry, immunohistochemistry and Alamar blue proliferation assays. When derived in advanced-DMEM/F12, all first trimester pMSC isolates exhibited maternal contamination (>72% XX cells, n=5), whilst 7/9 term pMSC isolates were >98% fetal. When derived in EGM-2, all first trimester (n=4) and term (n=9) pMSC isolates contained 95-100% fetal cells. Fetal pMSCs in EGM-2 proliferated 2-fold (first-trimester) or 4-fold (term) faster than those in advanced-DMEM/F12 (p<0.05, n=3). Fetal pMSCs in both media expressed the generic MSC marker profile (CD90 , CD105+, CD73 , CD31-, CD34-, CD144-). However, pMSCs transferred from EGM-2 to advanced-DMEM/F12 increased expression of smooth muscle cell markers calponin and α-smooth muscle actin, and decreased expression of the vascular cell marker VEGFR2 (n=3). Deriving first-trimester pMSC in EGM-2 dramatically reduces maternal dMSC contamination. Media affects fetal pMSC phenotype, and careful consideration should be given to application specific culture conditions.Deriving first-trimester pMSC in EGM-2 dramatically reduces maternal dMSC contamination. Media affects fetal pMSC phenotype, and careful consideration should be given to application specific culture conditions.