Objective To clarify the influence on component and pharmacological action of Astragalus polysaccharides(APS) as complementary therapeutic agents prepared by different extraction and purification techniques.Methods Co...Objective To clarify the influence on component and pharmacological action of Astragalus polysaccharides(APS) as complementary therapeutic agents prepared by different extraction and purification techniques.Methods Components of APS prepared by different extraction and purification techniques were analyzed,and these APS were used for synergy and attenuation of chemotherapy,radiotherapy treatment with H22 liver cancer and Lewis lung cancer of tumor-bearing mice,and also used for the regulation of immune function to immunosuppression mice.Results Experimental data were analyzed by means of statistical method to get pharmaco-result:A3(extracted by microwave assistance and purified by membrane separation)>A4(extracted by refluxing and purified by membrane separation)>A1(extracted by refluxing and no purification)≈A2(extracted by microwave assistance and no purification).There were no significant differences on pharmacodynamic action between A1 and A2.However,compared with A1 and A2,it was worth noting that A3 and A4 exhibited good pharmacodynamic action.Then A3-in and A4-in,the samples in dialyzer after dialysis,were separated and purified to get homogeneous APS,which were the principal constituents of APS in dialyzer,with the molecular weight(Mw) of 7669 and 14142 determined by HPGPC,respectively.The average Mw of APS outside of the dialyzer,A3-out was 3102 and A4-out 3256,which were the main compositions of A3 and A4,accounted for 79.63% and 53.92%,respectively.Conclusion APS with Mw about 5000 Da exhibit better antitumor effect and immunological activity.Refluxing,microwave assistance extractions,and membrane enrichment techniques bring different cases on Mw distribution,components and pharmacodynamic action,and obviously exhibit relationship among component,Mw distribution,and pharmacological action.展开更多
On the base of the one step, operator independent method which was set up by Christophe A.E., the pancreas was infused with cold University of Wisconsin(UW) solution for the preservation, ...On the base of the one step, operator independent method which was set up by Christophe A.E., the pancreas was infused with cold University of Wisconsin(UW) solution for the preservation, digested by the collagenase P, circuited with HBSS+5%fetal calf serum(FCS)+10mmol/L Hepes solution, and separated with the stainless steel mesh. The number of the collected islets were 400000～1800000 per pancreas, i.e. about 12150/g pancreas. After purification, the recovery was 350000～1700000 per pancreas, i.e. about 10250/g pancreas, the recovery rate was above 80%, and the purity of the final preparation was above 95%. The insulin secretion in the response to the high concentration glucose (22 mmol/L) stimulation was apparently different on the 1,3,5 day of the cultural islets, which the high level of insulin was three times the low level (5.5 mmol/L) on the 5th day, and the insulin level of the double stimulation under perfusion conditions is apparently higher than low glucose. The result demonstrated that the purified islets were functionally alive. Histological studies also show that the shape of islets are complete, and the β cell was specially stained by the dithizone (DTZ). The Trypan Blue staining had shown the living cell was above 90%. In conclusion, the new method was highly practical and yielded higher concentration of active pancreatic islets.展开更多
As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naph...As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.展开更多
Refining and purification is a significant way to obtain pure and high-quality magnesium alloy melts.This paper summarizes the flux refining methods and non-flux purification methods(blowing purification,filtration pu...Refining and purification is a significant way to obtain pure and high-quality magnesium alloy melts.This paper summarizes the flux refining methods and non-flux purification methods(blowing purification,filtration purification,electromagnetic purification and ultrasonic purification).It also introduces the composite refining technologies that have been widely researched and applied in recent years,including low-voltage pulse electromagnetic technology,ultrasonic argon purification,self-purification technology and non-flux continuous purification technology.Among them,the non-flux continuous purification technology integrates a variety of purification methods,which can produce high-quality magnesium alloy continuously and steadily,realize environmental protection production,and achieve remarkable technical and economic benefits.展开更多
Soil nematodes are useful ecological indicators and can be extracted from soil by a variety of techniques.Because the extracted nematode samples(suspensions)can be quite turbid(i.e.,they contain soil particles and org...Soil nematodes are useful ecological indicators and can be extracted from soil by a variety of techniques.Because the extracted nematode samples(suspensions)can be quite turbid(i.e.,they contain soil particles and organic particles in addition to nematodes),quantitative and taxonomic analyses of the nematodes by microscopy can be difficult.In this study,the following three methods for cleaning turbid suspensions obtained from Baermann funnels were assessed:repeated centrifugation at 692.5´g for 1 min,repeated settling at low-temperature(4°C)for 24 h,and a combination of low-temperature settling and centrifugation.Nematodes were extracted with Baermann funnels from soil samples collected from four land-use types(since land-use type can affect the turbidity of nematode suspensions),and the resulting suspensions were cleaned by the three methods before nematode abundance was assessed.As a control,samples(i.e.,suspensions)were simply diluted with water,and nematodes were counted in the entire volume.The results showed that,within each land-use type,nematode abundance did not significantly differ between the control and the three cleaning methods.Averaged across all land-use types,however,the nematode recovery rate was slightly higher with repeated centrifugation than with the other two cleaning methods.Therefore,the proposed methods are sound for cleaning turbid nematode suspensions,and repeated centrifugation is the most efficient method.展开更多
基金The National Key Scientific and Technological Project in 11th Five-year Plan (No:2009ZX09301-007)
文摘Objective To clarify the influence on component and pharmacological action of Astragalus polysaccharides(APS) as complementary therapeutic agents prepared by different extraction and purification techniques.Methods Components of APS prepared by different extraction and purification techniques were analyzed,and these APS were used for synergy and attenuation of chemotherapy,radiotherapy treatment with H22 liver cancer and Lewis lung cancer of tumor-bearing mice,and also used for the regulation of immune function to immunosuppression mice.Results Experimental data were analyzed by means of statistical method to get pharmaco-result:A3(extracted by microwave assistance and purified by membrane separation)>A4(extracted by refluxing and purified by membrane separation)>A1(extracted by refluxing and no purification)≈A2(extracted by microwave assistance and no purification).There were no significant differences on pharmacodynamic action between A1 and A2.However,compared with A1 and A2,it was worth noting that A3 and A4 exhibited good pharmacodynamic action.Then A3-in and A4-in,the samples in dialyzer after dialysis,were separated and purified to get homogeneous APS,which were the principal constituents of APS in dialyzer,with the molecular weight(Mw) of 7669 and 14142 determined by HPGPC,respectively.The average Mw of APS outside of the dialyzer,A3-out was 3102 and A4-out 3256,which were the main compositions of A3 and A4,accounted for 79.63% and 53.92%,respectively.Conclusion APS with Mw about 5000 Da exhibit better antitumor effect and immunological activity.Refluxing,microwave assistance extractions,and membrane enrichment techniques bring different cases on Mw distribution,components and pharmacodynamic action,and obviously exhibit relationship among component,Mw distribution,and pharmacological action.
文摘On the base of the one step, operator independent method which was set up by Christophe A.E., the pancreas was infused with cold University of Wisconsin(UW) solution for the preservation, digested by the collagenase P, circuited with HBSS+5%fetal calf serum(FCS)+10mmol/L Hepes solution, and separated with the stainless steel mesh. The number of the collected islets were 400000～1800000 per pancreas, i.e. about 12150/g pancreas. After purification, the recovery was 350000～1700000 per pancreas, i.e. about 10250/g pancreas, the recovery rate was above 80%, and the purity of the final preparation was above 95%. The insulin secretion in the response to the high concentration glucose (22 mmol/L) stimulation was apparently different on the 1,3,5 day of the cultural islets, which the high level of insulin was three times the low level (5.5 mmol/L) on the 5th day, and the insulin level of the double stimulation under perfusion conditions is apparently higher than low glucose. The result demonstrated that the purified islets were functionally alive. Histological studies also show that the shape of islets are complete, and the β cell was specially stained by the dithizone (DTZ). The Trypan Blue staining had shown the living cell was above 90%. In conclusion, the new method was highly practical and yielded higher concentration of active pancreatic islets.
基金support of the National Natural Science Foundation of China(Nos.22378369 and 22205207)Major Project of Natural Science Foundation of Zhejiang Province(LD24B060001).
文摘As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.
基金The authors gratefully acknowledge the financial support provided by 2018 Dongguan Key Technology Key Projects(2019622134013)。
文摘Refining and purification is a significant way to obtain pure and high-quality magnesium alloy melts.This paper summarizes the flux refining methods and non-flux purification methods(blowing purification,filtration purification,electromagnetic purification and ultrasonic purification).It also introduces the composite refining technologies that have been widely researched and applied in recent years,including low-voltage pulse electromagnetic technology,ultrasonic argon purification,self-purification technology and non-flux continuous purification technology.Among them,the non-flux continuous purification technology integrates a variety of purification methods,which can produce high-quality magnesium alloy continuously and steadily,realize environmental protection production,and achieve remarkable technical and economic benefits.
基金This study was supported by the Natural Science Fund of China(41877055)Natural Science Foundation for Distinguished Young Scholars of Hunan Province given to Jie Zhao+2 种基金the Guangxi Natural Science Foundation Program(2018GXNSFAA281008)the Foundation for Young Scholars in Western China of CAS given to Jie Zhao(A class)the program of the Youth Innovation Promotion Association of Chinese Academy of Sciences(Y201969)。
文摘Soil nematodes are useful ecological indicators and can be extracted from soil by a variety of techniques.Because the extracted nematode samples(suspensions)can be quite turbid(i.e.,they contain soil particles and organic particles in addition to nematodes),quantitative and taxonomic analyses of the nematodes by microscopy can be difficult.In this study,the following three methods for cleaning turbid suspensions obtained from Baermann funnels were assessed:repeated centrifugation at 692.5´g for 1 min,repeated settling at low-temperature(4°C)for 24 h,and a combination of low-temperature settling and centrifugation.Nematodes were extracted with Baermann funnels from soil samples collected from four land-use types(since land-use type can affect the turbidity of nematode suspensions),and the resulting suspensions were cleaned by the three methods before nematode abundance was assessed.As a control,samples(i.e.,suspensions)were simply diluted with water,and nematodes were counted in the entire volume.The results showed that,within each land-use type,nematode abundance did not significantly differ between the control and the three cleaning methods.Averaged across all land-use types,however,the nematode recovery rate was slightly higher with repeated centrifugation than with the other two cleaning methods.Therefore,the proposed methods are sound for cleaning turbid nematode suspensions,and repeated centrifugation is the most efficient method.
