Migration and distribution of saline ions in bauxite residue during water leaching

Bauxite residue,a highly saline solid waste produced from digestion of bauxite for alumina production,is hazardous to the environment and restricts vegetation establishment in bauxite residue disposal areas.A novel water leaching process proposed here was used to investigate the dynamic migration and vertical distribution of saline ions in bauxite residue.The results show that water leaching significantly reduced the salinity of bauxite residue,leaching both saline cations Na+,K+,Ca2+and anions CO32-,SO42-,HCO3-.Na+and K+migrated from 40-50 to 20-30 cm of the column,presenting a high migration capacity.The migration capacity of Ca2+was lower and accumulated at 30-40 cm of the column.CO32-initially distributed at 20-30 cm of the column,subsequently transported to 30-40 cm of the column,and finally returned to 20-30 cm of the column along with evaporation.SO42-was originally distributed at 40-50 cm,but finally migrated to 20-30 cm of the column.Nevertheless,HCO3-remained at the bottom of the column,and its migratory was less affected by evaporation.

Does hydrological fluctuation alter impacts of species richness on biomass in wetland plant communities?

Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary with plant species.Therefore,we hypothesized that hydrological fluctuation changes effects of species richness on productivity of wetland plant communities.Methods We constructed wetland plant communities consisting of three or six wetland plant species and subjected them to hydrological fluctuation(i.e.gradually changing water level)of two frequencies and two ranges,with unchanged water level as the control.We measured height,root and shoot dry mass of each plant at harvest.Important Findings Hydrological fluctuation significantly decreased biomass of wetland plant communities,which was due to impacts of fluctuation range,but not those of fluctuation frequency.Community biomass was significantly higher when species richness was higher,and such an effect did not depend on hydrological fluctuation.Therefore,hydrological fluctuation can decrease the productivity of wetland plant communities but may not alter the diversity-productivity relationship.

Long-term outcome and prognostic factors of combined hepatocellular carcinoma and cholangiocarcinoma after curative resection

Background:Combinedhepatocellular carcinoma and cholangiocarcinoma(cHCC-CC)is a rare subtype of primary liver cancers.Its prognostic factors remain unclear.The study aimed to evaluate its long-termoutcome and prognostic factors by retrospectively reviewing the series of cHCC-CC after curative resection from our institute.Methods:Atotal of 55 pathologically confirmed cHCC-CC patients undergoing curative resections between January 2003 and January 2018 at the First Affiliated Hospital of Sun Yat-sen University(Guangzhou,China)were included.The clinicopathological and follow-up data were retrieved.Overall survival(OS)and recurrence-free survivals(RFS)were analysed by Kaplan–Meier curve.The independent prognostic factors were determined by using univariate andmultivariate Cox analyses.Results:Therewere 41 males and 14 females,with a median age of 51.0(interquartile range,44.0–60.0)years.The 1-,3-,and 5-year OS and RFS rates in cHCC-CC were 80.0%,25.5%,and 16.4%,respectively,and 52.7%,21.8%,and 10.9%,respectively.The median OS and RFS were 24.9 and 14.5 months,respectively.Univariate and multivariate analyses revealed that elevated alpha-fetal protein(AFP)and/or CA19-9,vascular invasion,local extra-hepatic invasion,and lymph-node metastasis(LNM)were independent unfavorable prognostic factors for OS and RFS(all P<0.005).Furthermore,elevated AFP and/or CA19-9 were independent unfavorable prognostic factors in various subgroups of cHCC-CC,including patients aged<60 years,positive hepatitis B surface antigen,cirrhosis,single tumor,tumor size5 cm,no vascular invasion,no LNM,and no local extra-hepatic invasion(all P<0.05).Conclusions:ElevatedAFP and/or CA19-9,vascular invasion,local extra-hepatic invasion,and LNM were independent unfavorable prognostic factors for long-term survival of cHCC-CC undergoing curative resections.Patients with normal levels of AFP and CA19-9 had better prognosis.

Catalytic oxidation of ethyl acetate on Ce-Mn-O catalysts modified by La

La/Ce_(0.5)Mn_(0.5) catalysts prepared by wetness impregnation of Ce_(_(0.5))Mn_(_(0.5)) with La(NO_(3))_(3)(aq) were used in catalytic oxidation of ethyl acetate.Characterization by X-ray diffractometer(XRD),H2 temperature programmed reduction(H2-TPR),X-ray photoelectron spectroscopy(XPS) and Raman shows that La/Ce_(0.5)Mn_(0.5) catalysts have fluorite-like structure.LalCe_(0.5)Mn_(0.5) catalyst presents high activity with T90(the temperature needed for 90% conversion) of 200℃,where ethyl acetate is almost completely converted into CO_(2).The conversion at 195℃ maintains at 80% for at least 100 h.The intermediates were mainly ethanol and acetaldehyde whose amounts are below250 × 10^(-6) and 16 × 10^(-6),respectively.In situ FTIR indicates that the modes of dissociative adsorption of ethyl acetate are related to surface oxygen species,which affect the stability of catalysts and the selectivity for ethanol and acetaldehyde intermediates.