This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline...This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline anion(HCO3^-,CO3^2-,OH^-,AlO2^-)concentration reduced from 38.89 to 25.50 mmol/L,leaching rate of soluble sodium was 80.86%with ammonium chloride addition of 0.75%,liquid/solid(L/S)ratio of 3(mL/g),temperature of 30°C and reaction time of 18 h;L/S ratio was the main factor affecting the removal of alkaline anion and the leaching of sodium.Furthermore,ammonium chloride promoted the dissolution of diaspore and changed the micro/morphological characteristics with the increase of massive structure.The findings of this work will contribute to achieve soil-formation of bauxite residue.展开更多
Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions...Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions and their dissolution behaviors were investigated based on the combination of single factors-orthogonal experiments and leaching stage experiment. Using a two-stage leaching, 86% of the soluble alkaline anions（CO3^2-, HCO4^-,Al（OH）4^-, OH^-） were leached with a L/S ratio of 2 mL/g, at 30 ℃, over 23 h. During the first stage of leaching, approximately 88% of alkaline anions were leached from the dissolution of free alkali（Na OH, carbonate, bicarbonate, NaAl（OH）4） with the rest originating from the dissolution of alkaline minerals（calcite, cancrinite and hydrogarnet）. Supernatant alkalinity was 69.78 mmol/L with CO3^2- accounting for 75%. Furthermore, carbonate leaching was controlled by solid film diffusion using the Stumm Model with an apparent activation energy of 10.24 kJ/mol.展开更多
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 wa...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.展开更多
Objective: To explore the changes and significance of homocysteine (Hcy), high sensitivity C reactive protein (hs-CRP) and coagulation function indexes in patients with acute cerebral infarction. Methods: A total of 1...Objective: To explore the changes and significance of homocysteine (Hcy), high sensitivity C reactive protein (hs-CRP) and coagulation function indexes in patients with acute cerebral infarction. Methods: A total of 110 patients with acute cerebral infarction were selected as the observation group, According to the symptoms of acute cerebral infarction to 96 h, whether the symptoms of neurological deficit were aggravated, the patients in the observation group could be divided into the progressive group (n=65 case) and the non progressive group (n=45 case), and 110 cases with normal physical examination results were selected as control group at the same time. The levels of blood lipid metabolism, Hcy, hs-CRP and blood coagulation function were compared in each group. Results: Single factor analysis showed a statistically significant difference in blood lipid metabolism, Hcy, hs-CRP and coagulation function between groups. Compared with the index level in the control group, the levels of TG, TC, LDL, Hcy, hs-CRP, D-dime and FIB in the observation group were significantly higher than those in the control group, and the HDL level was significantly decreased, the difference was statistically significant. The levels of TG, TC, LDL, Hcy, hs-CRP, D-dime and FIB in the progression group were significantly higher than those in the non progressive group, HDL level was significantly lower than that in the non progressive group showing significant difference. Correlation analysis showed that the severity of acute cerebral infarction was positively correlated with the levels of TG, TC, LDL, Hcy, hs-CRP, D-dime and FIB, and negatively correlated with HDL level. Conclusion: There are abnormalities of blood lipid metabolism and coagulation function in patients with acute cerebral infarction, and the levels of Hcy and hs-CRP increase significantly. Detection of all indexes is of great significance for evaluating the severity of acute cerebral infarction.展开更多
Apart from its obvious agronomic interest in feeding billions of people worldwide,the porcine species represents an irreplaceable experimental model for intestinal physiologists and nutritionists.In this review,we giv...Apart from its obvious agronomic interest in feeding billions of people worldwide,the porcine species represents an irreplaceable experimental model for intestinal physiologists and nutritionists.In this review,we give an overview on the fate of proteins that are not fully digested in the pig small intestine,and thus are transferred into the large intestine.In the large intestine,dietary and endogenous proteins are converted to peptides and amino acids(AA)by the action of bacterial proteases and peptidases.AA,which cannot,except in the neonatal period,be absorbed to any significant level by the colonocytes,are used by the intestinal microbes for protein synthesis and for the production of numerous metabolites.Of note,the production of the AA-derived metabolites greatly depends on the amount of undigested polysaccharides in the pig's diet.The effects of these AA-derived bacterial metabolites on the pig colonic epithelium have not yet been largely studied.However,the available data,performed on colonic mucosa,isolated colonic crypts and colonocytes,indicate that some of them,like ammonia,butyrate,acetate,hydrogen sulfide(H_(2)S),and p-cresol are active either directly or indirectly on energy metabolism in colonic epithelial cells.Further studies in that area will certainly gain from the utilization of the pig colonic organoid model,which allows for disposal of functional epithelial unities.Such studies will contribute to a better understanding of the potential causal links between diet-induced changes in the luminal concentrations of these AA-derived bacterial metabolites and effects on the colon epithelial barrier function and water/electrolyte absorption.展开更多
基金Projects(41877511,41842020) supported by the National Natural Science Foundation of ChinaProject(201509048) supported by the Environmental Protection’s Special Scientific Research for Chinese Public Welfare Industry
文摘This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline anion(HCO3^-,CO3^2-,OH^-,AlO2^-)concentration reduced from 38.89 to 25.50 mmol/L,leaching rate of soluble sodium was 80.86%with ammonium chloride addition of 0.75%,liquid/solid(L/S)ratio of 3(mL/g),temperature of 30°C and reaction time of 18 h;L/S ratio was the main factor affecting the removal of alkaline anion and the leaching of sodium.Furthermore,ammonium chloride promoted the dissolution of diaspore and changed the micro/morphological characteristics with the increase of massive structure.The findings of this work will contribute to achieve soil-formation of bauxite residue.
基金Project(41371475)supported by the National Natural Science Foundation of ChinaProject(201509048)supported by the Environmental Protection’s Special Scientific Research for Chinese Public Welfare Industry
文摘Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions and their dissolution behaviors were investigated based on the combination of single factors-orthogonal experiments and leaching stage experiment. Using a two-stage leaching, 86% of the soluble alkaline anions（CO3^2-, HCO4^-,Al（OH）4^-, OH^-） were leached with a L/S ratio of 2 mL/g, at 30 ℃, over 23 h. During the first stage of leaching, approximately 88% of alkaline anions were leached from the dissolution of free alkali（Na OH, carbonate, bicarbonate, NaAl（OH）4） with the rest originating from the dissolution of alkaline minerals（calcite, cancrinite and hydrogarnet）. Supernatant alkalinity was 69.78 mmol/L with CO3^2- accounting for 75%. Furthermore, carbonate leaching was controlled by solid film diffusion using the Stumm Model with an apparent activation energy of 10.24 kJ/mol.
基金Project(41371475)supported by the National Natural Science Foundation of ChinaProject(201509048)supported by the Environmental Protection’s Special Scientific Research for Chinese Public Welfare Industry
文摘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.
基金This study was supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region(:2016E02C127).
文摘Objective: To explore the changes and significance of homocysteine (Hcy), high sensitivity C reactive protein (hs-CRP) and coagulation function indexes in patients with acute cerebral infarction. Methods: A total of 110 patients with acute cerebral infarction were selected as the observation group, According to the symptoms of acute cerebral infarction to 96 h, whether the symptoms of neurological deficit were aggravated, the patients in the observation group could be divided into the progressive group (n=65 case) and the non progressive group (n=45 case), and 110 cases with normal physical examination results were selected as control group at the same time. The levels of blood lipid metabolism, Hcy, hs-CRP and blood coagulation function were compared in each group. Results: Single factor analysis showed a statistically significant difference in blood lipid metabolism, Hcy, hs-CRP and coagulation function between groups. Compared with the index level in the control group, the levels of TG, TC, LDL, Hcy, hs-CRP, D-dime and FIB in the observation group were significantly higher than those in the control group, and the HDL level was significantly decreased, the difference was statistically significant. The levels of TG, TC, LDL, Hcy, hs-CRP, D-dime and FIB in the progression group were significantly higher than those in the non progressive group, HDL level was significantly lower than that in the non progressive group showing significant difference. Correlation analysis showed that the severity of acute cerebral infarction was positively correlated with the levels of TG, TC, LDL, Hcy, hs-CRP, D-dime and FIB, and negatively correlated with HDL level. Conclusion: There are abnormalities of blood lipid metabolism and coagulation function in patients with acute cerebral infarction, and the levels of Hcy and hs-CRP increase significantly. Detection of all indexes is of great significance for evaluating the severity of acute cerebral infarction.
文摘Apart from its obvious agronomic interest in feeding billions of people worldwide,the porcine species represents an irreplaceable experimental model for intestinal physiologists and nutritionists.In this review,we give an overview on the fate of proteins that are not fully digested in the pig small intestine,and thus are transferred into the large intestine.In the large intestine,dietary and endogenous proteins are converted to peptides and amino acids(AA)by the action of bacterial proteases and peptidases.AA,which cannot,except in the neonatal period,be absorbed to any significant level by the colonocytes,are used by the intestinal microbes for protein synthesis and for the production of numerous metabolites.Of note,the production of the AA-derived metabolites greatly depends on the amount of undigested polysaccharides in the pig's diet.The effects of these AA-derived bacterial metabolites on the pig colonic epithelium have not yet been largely studied.However,the available data,performed on colonic mucosa,isolated colonic crypts and colonocytes,indicate that some of them,like ammonia,butyrate,acetate,hydrogen sulfide(H_(2)S),and p-cresol are active either directly or indirectly on energy metabolism in colonic epithelial cells.Further studies in that area will certainly gain from the utilization of the pig colonic organoid model,which allows for disposal of functional epithelial unities.Such studies will contribute to a better understanding of the potential causal links between diet-induced changes in the luminal concentrations of these AA-derived bacterial metabolites and effects on the colon epithelial barrier function and water/electrolyte absorption.
