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By a novel freeze-gelcasting technique, ceramic bodies with unidirectional ordered and gradient porous structures were fabricated, using tert-butyl alcohol (TBA)/acrylamide (AM)/ alumina (Al 2 O 3 ) slurries. TBA, which can freeze below 251C and volatilize rapidly above 301C, was used as a template for forming pores. The porous structures could be controlled by the temperature conditions, resulting in special unidirectional and gradient porous structures over a long range of several millimeters. At the same time, gelation of AM was successfully introduced in this process, and played an important role in strengthening the green bodies (with compression strength over 10 MPa). Sintered Al 2 O 3 with a high porosity showed high compression mechanical properties, which contributed to the high density of ceramic walls. This technique combines the two processes of cold freezing and thermal gelation in one procedure, and is considered to be potentially useful in many applications.

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ObjectiveTo assess the effectiveness of e-cigarettes in smoking cessation in the USA from 2017 to 2019, given the 2017 increase in high nicotine e-cigarette sales.MethodsIn 2017, the PATH Cohort Study included data on 3578 previous year smokers with a recent quit attempt and 1323 recent former smokers. Respondents reported e-cigarettes or other products used to quit cigarettes and many covariates associated with e-cigarette use. Study outcomes were 12+ months of cigarette abstinence and tobacco abstinence in 2019. We report weighted unadjusted estimates and use propensity score matched analyses with 1500 bootstrap samples to estimate adjusted risk differences (aRD).ResultsIn 2017, 12.6% (95% CI 11.3% to 13.9%) of recent quit attempters used e-cigarettes to help with their quit attempt, a decline from previous years. Cigarette abstinence for e-cigarette users (9.9%, 95% CI 6.6% to 13.2%) was lower than for no product use (18.6%, 95% CI 16.0% to 21.2%), and the aRD for e-cigarettes versus pharmaceutical aids was −7.3% (95% CI −14.4 to –0.4) and for e-cigarettes versus any other method was −7.7% (95% CI −12.2 to –3.2). Only 2.2% (95% CI 0.0% to 4.4%) of recent former smokers switched to a high nicotine e-cigarette. Subjects who switched to e-cigarettes appeared to have a higher relapse rate than those who did not switch to e-cigarettes or other tobacco, although the difference was not statistically significant.ConclusionsSales increases in high nicotine e-cigarettes in 2017 did not translate to more smokers using these e-cigarettes to quit smoking. On average, using e-cigarettes for cessation in 2017 did not improve successful quitting or prevent relapse.