Green manuring reduces cadmium accumulation in rice: Roles of iron plaque and dissolved organic matter.

In southern China, winter green manure is widely used in rice cropping systems for improving grain yields and soil fertility. Cd pollution has recently been reported in some of these paddy fields. Research on the in-depth understanding of how green manuring affects Cd absorption in rice is limited. This study aimed to investigate the impacts of different green manures, including single plantation and mixed plantation on the absorption of Cd by rice and explore the underlying mechanisms. Pot experiments demonstrated that compared with winter fallow-rice, green manuring treatments considerably decreased rice Cd content, promoted the conversion of bioavailable Cd fraction into a more stable form, induced the formation of iron plaque, and increased the content of humic-like fraction (HF) in soil dissolved organic matter (DOM). Treatment with mixed plantation resulted in a greater decrease in rice Cd content and an increase in HF and iron plaque contents than single plantation. Hydroponic experiments confirmed that both iron plaque and green manure-derived DOM significantly reduced the Cd content in rice seedlings. In conclusion, green manure incorporation is an efficient measure for the safe utilization of Cd-contaminated soil, and mixed plantation of different green manures exerts stronger effects.

Utility of adjuvant radioactive iodine therapy after reoperation in papillary thyroid carcinoma with cervical lymph node recurrence.

PURPOSE: The aim of this study was to evaluate the utility of RAI therapy after reoperation for patients with LN relapse. MATERIALS AND METHODS: We retrospectively evaluated PTC patients who had undergone reoperation due to cervical LN recurrence. We used the chi-square test, Fisher's exact test, Student's t test and the Mann-Whitney U test to compare characteristics between patients retreated with RAI and those who did not receive RAI after reoperation. A multivariate logistic regression model was used to determine the association between RAI and biochemical response. By means of the Kaplan-Meier estimator and a multivariate Cox proportional hazard model, we assessed whether administration of RAI after reoperation is associated with improved prognosis. RESULTS: RAI therapy was closely associated with a superior biochemical response in all selected patients according to both univariate (p = 0.012) and multivariate analyses (p = 0.020). Thirteen of 97 patients developed a second recurrence or progression of structural disease during follow-up. A Kaplan-Meier progression-free survival (PFS) curve showed that high post-retreatment thyroglobulin (Tg) levels (≥ 1 ng/mL) were associated with unfavourable prognosis (p = 0.0172). In the subgroup analysis, univariate analysis revealed that only patients without extranodal invasion who received adjuvant RAI therapy achieved better PFS than those who did not receive RAI therapy (p = 0.0203). Multivariate analysis showed that RAI (p = 0.045) also improved PFS in patients without extranodal invasion. CONCLUSIONS: Adjuvant RAI after reoperation for PTC recurrence/persistence was associated with a favourable biochemical response and tended to increase PFS. Specifically, it was significantly associated with improved PFS only in patients without extranodal extension.