The solubilization and protection of curcumin (Cur) by mixed surfactants were studied through the determination about the critical micellar concentration (CMC) of the mixed surfactants of Tween 80 and dodecyl trimethyl ammonium bromide (DTAB), molar solubilization ratio (MSR), degradation rate (k) of Cur in pH 13 solution and mixed surfactant solutions prepared at pH 13. The results showed that when Tween 80 was used alone, it exhibited high solubilization ability but poor stability. DTAB was used alone, it showed strong stability but poor solubilization ability. When DTAB was mixed with Tween 80 at different mole fractions, the stability of Cur was enhanced, and the best stability was observed when the mole fraction of DTAB was 0.4, although the solubilization ability was not the best at this mole fraction, but MSR was increased by 1.7 times compared to DTAB used alone. Mixed surfactant not only increased the solubility but also improved the stability of Cur. In addition, mixed surfactant has the advantages of less dosage and low toxicity, which is worth popularizing in application.

Objective To understand the current situation of soil-transmitted nematode infections and influencing factors of pupils in rural areas of Yi Ethnicity in Butuo County, Sichuan Province, so as to provide the evidence for the prevention and control of soil-transmitted nematode infections. Methods In 2016, the pupils of 2 villages in Butuo County were selected by the multi-stage random sampling method, and the relevant information was obtained by questionnaires, including social demographic information, diet and hygiene habits and acknowledge of parasitic disease prevention. The soil-transmitted nematode infections were examined by Kato-Katz technique. The results were statistically analyzed by the single factor analysis and multivariate logistic regression methods. Results A total of 160 pupils were investigated in this survey. The soil-transmitted nematodes included Ascaris lumbricoides, Trichuris trichiura and hookworm. The overall infection rate was 89.38%, and the multi-infection rate was 54.55%. The infection rates of A. lumbricoides and T. trichiura were higher. The infection densities were mild (75.68%) or moderate (22.97%). The logistic regression analysis showed that the protective factor of soil-transmitted nematode infections was the knowledge about correct diet and health habits notified by teachers (OR = 0.67), but the risk factor was drinking unboiled water (OR = 19.26). Conclusions The infection rate of nematodes is still high in the pupils in rural areas of Yi Ethnicity in Butuo County, Sichuan Province. Therefore, we should strengthen the prevention and control of soil-transmitted nematode infections, especially A. lumbricoides and T. trichiura infections, and mostly develop the teachers’function in health education.