The reduced ability of fatty acids to dissolve and disperse at low temperatures limits their effectiveness in winter applications.In this study,a green and environment-friendly reagent,polyethylene glycol 2000(PEG-200...The reduced ability of fatty acids to dissolve and disperse at low temperatures limits their effectiveness in winter applications.In this study,a green and environment-friendly reagent,polyethylene glycol 2000(PEG-2000),was used to evaluate its effect on the collecting performance of sodium oleate during scheelite flotation at low temperatures.The effect of PEG-2000 on the flotation of scheelite with the collector sodium oleate(NaOL)was studied by flotation tests,surface tension tests,infrared spectral analysis,and zeta potential measurements.Flotation tests showed that adding PEG-2000 can enhance the collecting ability of NaOL on scheelite at low temperature(5℃).The recovery of scheelite with the mixed collector of PEG-200 and NaOL is 4.39%higher than that with NaOL only.The surface tension tests,infrared spectral analysis and zeta potential measurements revealed that PEG-2000 and OL^(−)are co-adsorbed on the scheelite surface at low temperatures.The presence of PEG-2000 promoted the increase of the adsorption concentration of oleate ions(OL^(−))on the scheelite surface.The reason was that PEG-2000 has a shielding effect on the electrostatic repulsion between the OL^(−)groups,which changes the micellar configuration of OL^(−)in the solution system and makes the OL^(−)gather more tightly on the surface of scheelite,leading to the enhancement of its hydrophobicity.This discovery provides a reference for the development of collecting reagents for efficient flotation recovery of scheelite under low temperature environment.展开更多
Tobacco mosaic virus(TMV) causes significant yield loss in susceptible crops irrigated with contaminated water. However, detection of TMV in water is difficult owing to extremely low concentrations of the virus. Here,...Tobacco mosaic virus(TMV) causes significant yield loss in susceptible crops irrigated with contaminated water. However, detection of TMV in water is difficult owing to extremely low concentrations of the virus. Here, we developed a simple method for the detection and quantification of TMV in irrigation water. TMV was reliably detected at concentrations as low as 10 viral copies/μL with real-time PCR. The sensitivity of detection was further improved using polyethylene glycol 6000(PEG6000, MW 6000) to concentrate TMV from water samples. Among the 28 samples from Shaanxi Province examined with our method, 17 were tested positive after virus concentration. Infectivity of TMV in the original water sample as well as after concentration was confirmed using PCR. The limiting concentration of TMV in water to re-infect plants was determined as 102 viral copies/mL. The method developed in this study offers a novel approach to detect TMV in irrigation water, and may provide an effective tool to control crop infection.展开更多
Aggregation of 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin (TPPS) was investigated in complex micelles composed of poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP) and poly(2-(dimethylamino)ethyl m...Aggregation of 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin (TPPS) was investigated in complex micelles composed of poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP) and poly(2-(dimethylamino)ethyl methylacrylate)-b-poly(Nisopropylacrylamide) (PDMAEMA-b-PNIPAM) in aqueous solutions.The resultant complex micelles had a complex P4VP/ PDMAEMA/TPPS core and a mixed PEG/PNIPAM shell.Different noncovalent interaction modes between the porphyrin and each copolymer accomplished a co-effect on the aggregation of TPPS.The formation of aggregates was pH-dependent.At pH 3.2–6.5,TPPS existed as a mixture of H-aggregates and monomers because of the aromatic-aromatic interaction with P4VP and electrostatic interaction with PDMAEMA.The monomers translated into J-aggregates,stabilized by electrostatic interaction with the both polyelectrolyte blocks,upon decreasing the pH to 1.6.The free-base monomer was the one and only form for the dye at pH 11.0 due to aromatic stacking with the pyridyl rings.展开更多
基金Project(2023JJ10070)supported by the Hunan Provincial Outstanding Youth Fund,ChinaProjects(51974364,52074355,52304316)supported by the National Natural Science Foundation of China。
文摘The reduced ability of fatty acids to dissolve and disperse at low temperatures limits their effectiveness in winter applications.In this study,a green and environment-friendly reagent,polyethylene glycol 2000(PEG-2000),was used to evaluate its effect on the collecting performance of sodium oleate during scheelite flotation at low temperatures.The effect of PEG-2000 on the flotation of scheelite with the collector sodium oleate(NaOL)was studied by flotation tests,surface tension tests,infrared spectral analysis,and zeta potential measurements.Flotation tests showed that adding PEG-2000 can enhance the collecting ability of NaOL on scheelite at low temperature(5℃).The recovery of scheelite with the mixed collector of PEG-200 and NaOL is 4.39%higher than that with NaOL only.The surface tension tests,infrared spectral analysis and zeta potential measurements revealed that PEG-2000 and OL^(−)are co-adsorbed on the scheelite surface at low temperatures.The presence of PEG-2000 promoted the increase of the adsorption concentration of oleate ions(OL^(−))on the scheelite surface.The reason was that PEG-2000 has a shielding effect on the electrostatic repulsion between the OL^(−)groups,which changes the micellar configuration of OL^(−)in the solution system and makes the OL^(−)gather more tightly on the surface of scheelite,leading to the enhancement of its hydrophobicity.This discovery provides a reference for the development of collecting reagents for efficient flotation recovery of scheelite under low temperature environment.
基金supported by the Key Technology Program of China National Tobacco Corporation (110200902046)111 Project from the Education Ministry of China, (No.B07049)the National High-tech R&D Program of China (no. 2012AA101504)
文摘Tobacco mosaic virus(TMV) causes significant yield loss in susceptible crops irrigated with contaminated water. However, detection of TMV in water is difficult owing to extremely low concentrations of the virus. Here, we developed a simple method for the detection and quantification of TMV in irrigation water. TMV was reliably detected at concentrations as low as 10 viral copies/μL with real-time PCR. The sensitivity of detection was further improved using polyethylene glycol 6000(PEG6000, MW 6000) to concentrate TMV from water samples. Among the 28 samples from Shaanxi Province examined with our method, 17 were tested positive after virus concentration. Infectivity of TMV in the original water sample as well as after concentration was confirmed using PCR. The limiting concentration of TMV in water to re-infect plants was determined as 102 viral copies/mL. The method developed in this study offers a novel approach to detect TMV in irrigation water, and may provide an effective tool to control crop infection.
基金supported by the National Natural Science Foundation of China (50830103 & 20904025)National Basic Research Program of China (973 Program,2011CB932500)the Open Research Fund Program of ChangChun Institute of Applied Chemistry Chinese Academy of Sciences
文摘Aggregation of 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin (TPPS) was investigated in complex micelles composed of poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP) and poly(2-(dimethylamino)ethyl methylacrylate)-b-poly(Nisopropylacrylamide) (PDMAEMA-b-PNIPAM) in aqueous solutions.The resultant complex micelles had a complex P4VP/ PDMAEMA/TPPS core and a mixed PEG/PNIPAM shell.Different noncovalent interaction modes between the porphyrin and each copolymer accomplished a co-effect on the aggregation of TPPS.The formation of aggregates was pH-dependent.At pH 3.2–6.5,TPPS existed as a mixture of H-aggregates and monomers because of the aromatic-aromatic interaction with P4VP and electrostatic interaction with PDMAEMA.The monomers translated into J-aggregates,stabilized by electrostatic interaction with the both polyelectrolyte blocks,upon decreasing the pH to 1.6.The free-base monomer was the one and only form for the dye at pH 11.0 due to aromatic stacking with the pyridyl rings.
