The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as eithe...The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as either granules or flocs. The results showed that the rate of ammonium oxidation in both cultures increased significantly as temperature increased from 10 to 30 °C. The specific ammonium oxidation rate with the granules was 2-3 times higher than that with flocs at the same temperature. Nitrification at various FA concentrations and temperatures combination exhibited obvious inhibition in ammonium oxidation rate when FA was 90 mg·L 1 and tempera- ture dropped to 10 °C in the two systems. However, the increase in substrate oxidation rate of ammonia at 30 °C was observed. The results suggested that higher reaction temperature was helpful to reduce the toxicity of FA. Granules appeared to be more tolerant to FA attributed to the much fraction of ammonia oxidizing bacteria (AOB) and higher resistance to the transfer of ammonia into the bacterial aggregates, whereas in the floc system, the bacteria distributed throughout the entire aggregate. These results may contribute to the applicability of the nitrifying granules in wastewater treatment operated at high ammonium concentration.展开更多
AIM:To evaluate the role of endoscopic retrograde cholangiopancreatography(ERCP) in patients with sickle cell disease(SCD) .METHODS:Two hundred and twenty four SCD patients with cholestatic jaundice(CJ) had ERCP.The i...AIM:To evaluate the role of endoscopic retrograde cholangiopancreatography(ERCP) in patients with sickle cell disease(SCD) .METHODS:Two hundred and twenty four SCD patients with cholestatic jaundice(CJ) had ERCP.The indications for ERCP were based on clinical and biochemical evidence of CJ and ultrasound findings.RESULTS:Two hundred and forty ERCPs were performed.The indications for ERCP were:CJ only in 79,CJ and dilated bile ducts without stones in 103,and CJ and bile duct stones in 42.For those with CJ only,ERCP was normal in 42(53.2%) ,and 13(16.5%) had dilated bile ducts without an obstructive cause.In the remaining 22,there were bile duct stones with or without dilation.For those with CJ,dilated bile ducts and no stones,ERCP was normal in 17(16.5%) ,and 28(27.2%) had dilated bile ducts without an obstructive cause.In the remaining 58,there were bile ducts stones with or without dilation.For those with CJ and bile duct stones,ERCP was normal in two(4.8%) ,and 14(33.3%) had dilated bile ducts without an obstructive cause.In the remaining 26,there were bile duct stones with or without dilatation.CONCLUSION:Considering the high frequency of biliary sludge and bile duct stones in SCD,endoscopic sphincterotomy might prove helpful in these patients.展开更多
Anthraquinone dyes,which contain anthraquinone chromophore groups,are the second largest class of dyes after azo dyes and are used extensively in textile industries.The majority of these dyes are resistant to degradat...Anthraquinone dyes,which contain anthraquinone chromophore groups,are the second largest class of dyes after azo dyes and are used extensively in textile industries.The majority of these dyes are resistant to degradation because of their complex and stable structures;consequently,a large number of anthraquinone dyes find their way into the environment causing serious pollution.At present,the microbiological approach to treating printing and dyeing wastewater is considered to be an economical and feasible method,and reports regarding the bacterial degradation of anthraquinone dyes are increasing.This paper reviews the classification and structures of anthraquinone dyes,summarizes the types of degradative bacteria,and explores the possible mechanisms and influencing factors of bacterial anthraquinone dye degradation.Present research progress and existing problems are further discussed.Finally,future research directions and key points are presented.展开更多
Studies of rock slices showed that there were many kinds of symbioses between bacteria and algae and corals-stromatoporoids in the coral-stromatoporoid reefs from the Devonian Ganxi section of Sichuan and the Dushan s...Studies of rock slices showed that there were many kinds of symbioses between bacteria and algae and corals-stromatoporoids in the coral-stromatoporoid reefs from the Devonian Ganxi section of Sichuan and the Dushan section of Guizhou in South China. They included encrustations, microborings, bioclaustration, etc. In the host corals-stromatoporoids invaded by bacteria and algae were many residues of dead soft issue in the infected parts, where the skeletal structures were injured. Therefore, we considered there were direct interactions between corals-stromatoporoids and bacteria and algae in coral-stromatoporoid reefs, which included that bacteria and algae blocked growth of corals-stromatoporoids and the latter had the ability of self-healing. And the bacteria and algae usually was the active side. In the Middle Devonian with normal seawater condition, corals and stromatoporoids had the ability to resist the invasion of bacteria and algae, and the host coral-stromatoporoids would not be killed; but in the Late Devonian with deterioration of seawater quality, the ability of bacteria and algae infection increased while corals-stromatoporoids' ability to resist infection declined, and therefore the host corals-stromatoporoids would be dead. Hence we suggested that the invading of bacteria and algae was a possible biokiller for mass-extinction of the Devonian coral-stromatoporoid reefs ecosystem. Beyond that, blooming of bacteria and algae and its triggering cumulative environmental effects played an important role in the reduction and extinction of metazoan in the Late Devonian. Furthermore, it can be used as a useful example to learn the trend and the reasons for the disease and decrease of modern coral reefs.展开更多
基金Supported by the Project of Scientific Research Base and Scientific Innovation Platform of Beijing Municipal Education CommissionNational Key Science and Technology Special Projects
文摘The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as either granules or flocs. The results showed that the rate of ammonium oxidation in both cultures increased significantly as temperature increased from 10 to 30 °C. The specific ammonium oxidation rate with the granules was 2-3 times higher than that with flocs at the same temperature. Nitrification at various FA concentrations and temperatures combination exhibited obvious inhibition in ammonium oxidation rate when FA was 90 mg·L 1 and tempera- ture dropped to 10 °C in the two systems. However, the increase in substrate oxidation rate of ammonia at 30 °C was observed. The results suggested that higher reaction temperature was helpful to reduce the toxicity of FA. Granules appeared to be more tolerant to FA attributed to the much fraction of ammonia oxidizing bacteria (AOB) and higher resistance to the transfer of ammonia into the bacterial aggregates, whereas in the floc system, the bacteria distributed throughout the entire aggregate. These results may contribute to the applicability of the nitrifying granules in wastewater treatment operated at high ammonium concentration.
文摘AIM:To evaluate the role of endoscopic retrograde cholangiopancreatography(ERCP) in patients with sickle cell disease(SCD) .METHODS:Two hundred and twenty four SCD patients with cholestatic jaundice(CJ) had ERCP.The indications for ERCP were based on clinical and biochemical evidence of CJ and ultrasound findings.RESULTS:Two hundred and forty ERCPs were performed.The indications for ERCP were:CJ only in 79,CJ and dilated bile ducts without stones in 103,and CJ and bile duct stones in 42.For those with CJ only,ERCP was normal in 42(53.2%) ,and 13(16.5%) had dilated bile ducts without an obstructive cause.In the remaining 22,there were bile duct stones with or without dilation.For those with CJ,dilated bile ducts and no stones,ERCP was normal in 17(16.5%) ,and 28(27.2%) had dilated bile ducts without an obstructive cause.In the remaining 58,there were bile ducts stones with or without dilation.For those with CJ and bile duct stones,ERCP was normal in two(4.8%) ,and 14(33.3%) had dilated bile ducts without an obstructive cause.In the remaining 26,there were bile duct stones with or without dilatation.CONCLUSION:Considering the high frequency of biliary sludge and bile duct stones in SCD,endoscopic sphincterotomy might prove helpful in these patients.
基金supported by the National Natural Science Foundation of China(Nos.41721001 and 41630637)the Shaanxi Provincial Science and Technology Department(No.2017GY-151)+1 种基金the Education Department of Shaanxi Province(No.16JF010)the Shaanxi Sanqin Scholars Fund Project,China
文摘Anthraquinone dyes,which contain anthraquinone chromophore groups,are the second largest class of dyes after azo dyes and are used extensively in textile industries.The majority of these dyes are resistant to degradation because of their complex and stable structures;consequently,a large number of anthraquinone dyes find their way into the environment causing serious pollution.At present,the microbiological approach to treating printing and dyeing wastewater is considered to be an economical and feasible method,and reports regarding the bacterial degradation of anthraquinone dyes are increasing.This paper reviews the classification and structures of anthraquinone dyes,summarizes the types of degradative bacteria,and explores the possible mechanisms and influencing factors of bacterial anthraquinone dye degradation.Present research progress and existing problems are further discussed.Finally,future research directions and key points are presented.
基金financially supported by National Natural Science Foundation of China (Grant Nos.41072252,40872001 and 41290260)National Basic Research Program of China (Grant No.2011CB80800)Special Research Fund for the Doctoral Program of Higher Education of China (Grant No.20120145110012)
文摘Studies of rock slices showed that there were many kinds of symbioses between bacteria and algae and corals-stromatoporoids in the coral-stromatoporoid reefs from the Devonian Ganxi section of Sichuan and the Dushan section of Guizhou in South China. They included encrustations, microborings, bioclaustration, etc. In the host corals-stromatoporoids invaded by bacteria and algae were many residues of dead soft issue in the infected parts, where the skeletal structures were injured. Therefore, we considered there were direct interactions between corals-stromatoporoids and bacteria and algae in coral-stromatoporoid reefs, which included that bacteria and algae blocked growth of corals-stromatoporoids and the latter had the ability of self-healing. And the bacteria and algae usually was the active side. In the Middle Devonian with normal seawater condition, corals and stromatoporoids had the ability to resist the invasion of bacteria and algae, and the host coral-stromatoporoids would not be killed; but in the Late Devonian with deterioration of seawater quality, the ability of bacteria and algae infection increased while corals-stromatoporoids' ability to resist infection declined, and therefore the host corals-stromatoporoids would be dead. Hence we suggested that the invading of bacteria and algae was a possible biokiller for mass-extinction of the Devonian coral-stromatoporoid reefs ecosystem. Beyond that, blooming of bacteria and algae and its triggering cumulative environmental effects played an important role in the reduction and extinction of metazoan in the Late Devonian. Furthermore, it can be used as a useful example to learn the trend and the reasons for the disease and decrease of modern coral reefs.
