The Effect of Nationwide Organized Cancer Screening Programs on Gastric Cancer Mortality: A Synthetic Control Study.

BACKGROUND & AIMS: Nationwide organized gastric cancer (GC) screening programs have been running for decades in South Korea and Japan. This study conducted a quasi-experimental analysis to assess the population impact of these programs on GC mortality. METHODS: We used the flexible synthetic control method (SCM) to estimate the effect of the screening programs on age-standardized GC mortality and other upper gastrointestinal (UGI) diseases (esophageal cancer and peptic ulcer) among people aged ≥40 years. World Health Organization mortality data and country-level covariates from the World Bank and the Global Burden of Diseases study were used for the analyses. We compared postintervention trends in outcome with the counterfactual trend of the synthetic control and estimated average postintervention rate ratios (RRs) with associated 95% confidence intervals (CIs). A series of sensitivity analyses were conducted. RESULTS: The preintervention fits were acceptable for the analyses of South Korea and Japan's GC mortality but poor for Japan's other UGI disease mortality. The average postintervention RRs were 0.83 (95% CI, 0.71-0.96) for GC mortality and 0.72 (95% CI, 0.57-0.90) for other UGI disease mortality in South Korea. The RR reached 0.59 by the 15th year after the initiation of nationwide screening. For Japan, the average RRs were 0.97 (95% CI, 0.88-1.07) for GC mortality and 0.93 (95% CI, 0.68-1.28) for other UGI disease mortality. Sensitivity analysis reveals the result for Japan may potentially be biased. CONCLUSIONS: South Korea's nationwide GC screening has apparent benefits, whereas the Japanese program's effectiveness is uncertain. The experiences of South Korea and Japan could serve as a reference for other countries.

Ozone micro-bubble aeration using the ceramic ultrafiltration membrane with superior oxidation performance for 2, 4-D elimination.

Micro-bubble aeration is an efficient way to promote ozonation performance, but the technology is challenged by extensive energy cost. Here, a ceramic ultrafiltration membrane was used to achieve ozone micro-bubble (0-80 µm) aeration in a simple way at gaseous pressures of 0.14-0.19 MPa. Compared with milli-bubble aeration, micro-bubble aeration increased the equilibrium aquatic O3 concentrations by 1.53-3.25 times and apparent O3 transfer rates by 3.12-3.35 times at pH 5.0-8.0. Consequently, the •OH yield was 2.67-3.54 times via faster O3 transfer to the aquatic solution followed by decomposition rather than interfacial reaction. Ozone micro-bubble aeration outperformed milli-bubble aeration, with the degradation kinetics of 2,4-D being 3.08-4.36 times higher. Both O3-oxidation and •OH oxidation were important to the promotion with the contributions being 35.8%-45.9% and 54.1%-64.2%, respectively. The operational and water matric conditions influenced the oxidation performance via both O3 oxidation and •OH oxidation, which is reported for the first time. In general, the ceramic membrane offered a low-energy approach of ozone micro-bubble aeration for efficient pollutant degradation. The O3 oxidation and •OH oxidation were proportionally promoted by ozone micro-bubble due to O3 transfer enhancement. Thus, the promotive mechanism can be interpreted as the synchronous enchantment on ozone exposure and •OH exposure for the first time.