Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggr...Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggregate by suppressing the electrostatic repulsion between ionic head groups leading to the formation of micellar complex.With addition of surfactant,the conformation of polyion chain changes from stretched to random coiled to spherical,and at the same time more free micelles are formed by surfactants in mixtures.Increasing the length of spacer or tail chain in gemini surfactant will weaken its interaction with polyelectrolyte and simultaneously strengthen its tendency to self-assemble.The simulation results are consistent with experimental observations and reveal that the electrostatic interaction plays an important role in the interaction of polyelectrolyte with gemini sur- factant.展开更多
Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported ...Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.展开更多
An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular the...An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular ther-modynamic model has been proposed. The interfacial tension of surfactant-oil-water systems can be calculated from the surface tensions of pure oil and water by this model. The interfacial tension data for sodium dodecyl sulphate-heptane-water system, polyoxyethylene n-octylphenol-heptane-water system and hexadecyl trimethyl ammonium bromide-heptane-water system have been correlated. By using the adjustable parameters obtained, the interfacial tensions of these systems at other temperatures have been predicted. Both the correlated and the predicted values are satisfactory.展开更多
Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the...Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity （attached and ultrafine）, but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration （EEC） and ultrafine equilibrium equivalent concentration （EECUn）, ultrafine fraction （fb）, attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter （AMTD） ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations （GSD） of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter （AMD） of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.展开更多
The gas torque in a twin-rotor piston engine(TRPE) was modeled using adiabatic approximation with instantaneous combustion. The first prototype of TRPE was manufactured. This prototype is intended for high power densi...The gas torque in a twin-rotor piston engine(TRPE) was modeled using adiabatic approximation with instantaneous combustion. The first prototype of TRPE was manufactured. This prototype is intended for high power density engines and can produce 36 power strokes per shaft revolution. Compared with the conventional engines, the vector sum of combustion gas forces acting on each rotor piston in TRPE is a pure torque, and the combustion gas rotates the rotors while compresses the gas in the compression chamber at the same time. Mathematical modeling of gas force transmission was built. Expression for gas torque on each rotor was derived. Different variation patterns of the volume change of working chamber were introduced. The analytical and numerical results is presented to demonstrate the main characteristics of gas torque. The results show that the value of gas torque in TRPE falls to be less than zero before the combustion phase is finished; the time for one stroke is 30° in terms of the rotating angle of the output shaft; gas torque in one complete revolution of the output shaft has a period which is equal to 60° and it is necessary to put off the moment when gas torque becomes zero in order to export the maximum energy.展开更多
The quantitative structure-activity relationship(QSAR) of 2-alkyl-4-(biphenylylmethoxy) pyridine derivatives was studied.Three different alignment methods were used to get the models of the comparative molecular field...The quantitative structure-activity relationship(QSAR) of 2-alkyl-4-(biphenylylmethoxy) pyridine derivatives was studied.Three different alignment methods were used to get the models of the comparative molecular field analysis(CoMFA),the comparative molecular similarity indices analysis(CoMSIA),and the hologram quantitative structure?activity relationship(HQSAR).The statistical results from the established models show believable predictivity based on the cross-validated value(q2>0.5) and the non-validated value(r2>0.9),The analysis on contour maps of CoMFA and CoMSIA models suggests that hydrophobic and hydrogen-bond acceptor fields are important factors that affect the AT1 antagonistic activity of 2-alkyl-4-(biphenylylmethoxy) pyridine derivatives besides the steric and electrostatic fields,The structural modification information from different atom contributions in the HQSAR model is in agreement with that in the 3D-QSAR models.展开更多
Lunasia amara Blanco is a famous plant in South Sulawesi. It was used largely by local people as antibacteria and aphrodisiac. Quinoline alkaloid lunacridine was known as the active principle from Lunasia amara Blanco...Lunasia amara Blanco is a famous plant in South Sulawesi. It was used largely by local people as antibacteria and aphrodisiac. Quinoline alkaloid lunacridine was known as the active principle from Lunasia amara Blanco. Its activity was reported as a DNA Intercalating Topoisomerase II inhibitor. In this study, we have isolated and assayed the cytotoxic activity of lunacridine on P388 murine leukemia cells by MTT colorimetric assay （in vitro）. Lunacridine showed the less cytotoxic activity with the IC50 of 39.52 μg/mL. With the aim to explore the structural determinants responsible for this activity, molecular docking study have been carried out with DNA model using AutoDock 4.0 software with various total of energy evaluations （in silico）. The best docking reached at the total energy evaluations of 2.5 × 107 with the binding free energy of-6.63 kcal/mol. Analysis of the docking results was in accordance with the ability of lunacridine to intercalate between base pairs of DNA. Cytotoxic activity of lunacridine is less probably due to low affinity and molecular interaction. Therefore this study suggests to design and to develop lunacridine as a lead compound for anticancer drug.展开更多
Objective To explore the mechanism of An-Pressing manipulation in relieving energy crisis in chronic myofascial trigger points(MTrPs)by observing the effects of An-Pressing manipulation on adenosine triphosphate(ATP),...Objective To explore the mechanism of An-Pressing manipulation in relieving energy crisis in chronic myofascial trigger points(MTrPs)by observing the effects of An-Pressing manipulation on adenosine triphosphate(ATP),adenosine 5′-monophosphate(AMP)-activated protein kinase(AMPK)/peroxisome proliferator-activated receptorγcoactivator 1α(PGC-1α)pathway and mitochondrial ultrastructure of skeletal muscle cells in MTrPs rats.Methods Forty-eight male Sprague-Dawley rats were randomly divided into a blank group,a model group,a lidocaine group,and an An-Pressing manipulation group,with 12 rats in each group.The model group,lidocaine group and An-Pressing manipulation group were used to replicate the MTrPs rat model by blunt shock and centrifugal motion method.After modeling,the An-Pressing manipulation group was subjected to 7 times An-Pressing manipulation,once every other day;the lidocaine group was treated with 3 times of injection of lidocaine at the MTrPs,once every 6 d.The blank group and the model group were fed normally without intervention.After the intervention,local muscle tissue was taken to detect the content of ATP and the expression of AMPK,phosphorylated AMPK(phospho-AMPK),PGC-1α,and glucose transporter 4(GluT4),and the ultrastructure of mitochondria was observed under an electron microscope.Results Compared with the blank group,the ATP content in the model group was decreased(P<0.05),the protein expression levels of phospho-AMPK,PGC-1α,and GluT4 and the ratio of phospho-AMPK to AMPK were decreased(P<0.05);under the electron microscope,the number of mitochondria decreased,and they were deformed,small in volume,and had deformed cristae.Compared with the model group,the ATP contents in the An-Pressing manipulation group and the lidocaine group were increased(P<0.05),and the protein expression levels of phospho-AMPK,PGC-1α,and GluT4 and the ratio of phospho-AMPK to AMPK were increased(P<0.05);under the electron microscope,the number of mitochondria increased,the shape and size of the mitochondria were basically normal,and the cristae could be seen.Compared with the lidocaine group,phospho-AMPK and the ratio of phospho-AMPK to AMPK in the An-Pressing manipulation group were increased(P<0.05);under the electron microscope,the numbers of mitochondria were similar,and the shape and size of the mitochondria were basically normal without swelling,and the cristae could be observed.Conclusion An-Pressing manipulation can increase the ATP content in MTrPs tissue,improve the expression levels of PGC-1α and GluT4 proteins and the ratio of phospho-AMPK to AMPK;its mechanism may relate to the activation of AMPK/PGC-1α signaling pathway to promote the repair of mitochondrial damages.展开更多
Hydrogen sulfide(H_2S)has been found to be the third most important endogenous gaseous signaling molecule after nitric oxide(NO)and carbonic oxide(CO)and plays crucial roles in living organisms and biological systems....Hydrogen sulfide(H_2S)has been found to be the third most important endogenous gaseous signaling molecule after nitric oxide(NO)and carbonic oxide(CO)and plays crucial roles in living organisms and biological systems.Here we use aggregation-induced emission(AIE)of a small organic molecule(TPE-indo)to detect H_2S in both solution and living cells.TPE-indo can target mitochondria and aggregate to fluoresce,which can serve as a sensor for monitoring H_2S in the mitochondria.We regulate the fluorescence of AIE molecules by tuning the viscosity of the solution to form TPE-indo nanoparticles,constructing a probe for H_2S with good selectivity and high sensitivity.The nucleophilic addition of HS-to the TPE-indo is crucial for the rapid H_2S detection.The imaging and analysis of H_2S in mitochondria of living cells with the probe demonstrate potential biological applications.展开更多
Quantum chemical computations have been performed to evaluate the first and second hyperpolarizability quantities of the interference term, linear in the external static electric field, that appear in the electric fie...Quantum chemical computations have been performed to evaluate the first and second hyperpolarizability quantities of the interference term, linear in the external static electric field, that appear in the electric field-induced sum-frequency generation signal of chiral liquids. These are performed at the time-dependent Hartree-Fock level on the prototypical 1,1′-bi-2-naphtol chiral species.展开更多
Single-particle tracking photoactivated local- ization microscopy （sptPALM） has recently emerged as a powerful tool for high-density imaging and tracking of individual molecules in living cells. In this work, we hav...Single-particle tracking photoactivated local- ization microscopy （sptPALM） has recently emerged as a powerful tool for high-density imaging and tracking of individual molecules in living cells. In this work, we have monitored and compared the diffusion dynamics of TGF-β type II receptor （TβRII） at high expression level using both traditional single-particle tracking （SPT） and sptPALM. The ligand-induced aggregation of TβRII oligomers was further indicated by sptPALM. Due to the capacity of distinguishing and tracking single molecules within diffraction limit, sptPALM outperforms traditional SPT by providing more accurate biophysical information,展开更多
With the development of colloid interface and enzyme technologies,enzyme-containing reversed micellar system has been receiving much attention in bioseparation and bioconversion. Because of its high efficiency,it has ...With the development of colloid interface and enzyme technologies,enzyme-containing reversed micellar system has been receiving much attention in bioseparation and bioconversion. Because of its high efficiency,it has brought new opportunities for the development of molecular biotechnology. Reversed micelles represent nano-sized aqueous droplets stabilized by surfactant amphiphiles inside the bulk organic solvents. The entrapped enzymes have enhanced activities under those conditions as suited in the lipid bilayers of biological membranes. The fundamentals of enzyme-containing reversed micellar system are described in this paper,with special emphasis on the effects of surfactants varying in concentrations and structures. The latest study progress on the surfactants application in enzyme-containing reversed micelles is reviewed. The introduction of novel functional surfactants in micellar enzymology and their future development are also discussed.展开更多
基金Supported by the National Natural Science Foundation of China （No.20476025）, the Doctoral Research Foundation of the Ministry of Education of China （No.20050251004）, E-institute of Shanghai High Institution Grid （No.200303） and Shanghai Municipal Science and Technology Commission of China （No.05DJ14002）.
文摘Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggregate by suppressing the electrostatic repulsion between ionic head groups leading to the formation of micellar complex.With addition of surfactant,the conformation of polyion chain changes from stretched to random coiled to spherical,and at the same time more free micelles are formed by surfactants in mixtures.Increasing the length of spacer or tail chain in gemini surfactant will weaken its interaction with polyelectrolyte and simultaneously strengthen its tendency to self-assemble.The simulation results are consistent with experimental observations and reveal that the electrostatic interaction plays an important role in the interaction of polyelectrolyte with gemini sur- factant.
文摘Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.
基金Supported by the National Nature Science Foundation of China(No.29736170)
文摘An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular ther-modynamic model has been proposed. The interfacial tension of surfactant-oil-water systems can be calculated from the surface tensions of pure oil and water by this model. The interfacial tension data for sodium dodecyl sulphate-heptane-water system, polyoxyethylene n-octylphenol-heptane-water system and hexadecyl trimethyl ammonium bromide-heptane-water system have been correlated. By using the adjustable parameters obtained, the interfacial tensions of these systems at other temperatures have been predicted. Both the correlated and the predicted values are satisfactory.
文摘Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity （attached and ultrafine）, but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration （EEC） and ultrafine equilibrium equivalent concentration （EECUn）, ultrafine fraction （fb）, attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter （AMTD） ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations （GSD） of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter （AMD） of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.
基金Project(51175500)supported by the National Natural Science Foundation of China
文摘The gas torque in a twin-rotor piston engine(TRPE) was modeled using adiabatic approximation with instantaneous combustion. The first prototype of TRPE was manufactured. This prototype is intended for high power density engines and can produce 36 power strokes per shaft revolution. Compared with the conventional engines, the vector sum of combustion gas forces acting on each rotor piston in TRPE is a pure torque, and the combustion gas rotates the rotors while compresses the gas in the compression chamber at the same time. Mathematical modeling of gas force transmission was built. Expression for gas torque on each rotor was derived. Different variation patterns of the volume change of working chamber were introduced. The analytical and numerical results is presented to demonstrate the main characteristics of gas torque. The results show that the value of gas torque in TRPE falls to be less than zero before the combustion phase is finished; the time for one stroke is 30° in terms of the rotating angle of the output shaft; gas torque in one complete revolution of the output shaft has a period which is equal to 60° and it is necessary to put off the moment when gas torque becomes zero in order to export the maximum energy.
基金Project(20876180) supported by the National Natural Science Foundation of China
文摘The quantitative structure-activity relationship(QSAR) of 2-alkyl-4-(biphenylylmethoxy) pyridine derivatives was studied.Three different alignment methods were used to get the models of the comparative molecular field analysis(CoMFA),the comparative molecular similarity indices analysis(CoMSIA),and the hologram quantitative structure?activity relationship(HQSAR).The statistical results from the established models show believable predictivity based on the cross-validated value(q2>0.5) and the non-validated value(r2>0.9),The analysis on contour maps of CoMFA and CoMSIA models suggests that hydrophobic and hydrogen-bond acceptor fields are important factors that affect the AT1 antagonistic activity of 2-alkyl-4-(biphenylylmethoxy) pyridine derivatives besides the steric and electrostatic fields,The structural modification information from different atom contributions in the HQSAR model is in agreement with that in the 3D-QSAR models.
文摘Lunasia amara Blanco is a famous plant in South Sulawesi. It was used largely by local people as antibacteria and aphrodisiac. Quinoline alkaloid lunacridine was known as the active principle from Lunasia amara Blanco. Its activity was reported as a DNA Intercalating Topoisomerase II inhibitor. In this study, we have isolated and assayed the cytotoxic activity of lunacridine on P388 murine leukemia cells by MTT colorimetric assay （in vitro）. Lunacridine showed the less cytotoxic activity with the IC50 of 39.52 μg/mL. With the aim to explore the structural determinants responsible for this activity, molecular docking study have been carried out with DNA model using AutoDock 4.0 software with various total of energy evaluations （in silico）. The best docking reached at the total energy evaluations of 2.5 × 107 with the binding free energy of-6.63 kcal/mol. Analysis of the docking results was in accordance with the ability of lunacridine to intercalate between base pairs of DNA. Cytotoxic activity of lunacridine is less probably due to low affinity and molecular interaction. Therefore this study suggests to design and to develop lunacridine as a lead compound for anticancer drug.
文摘Objective To explore the mechanism of An-Pressing manipulation in relieving energy crisis in chronic myofascial trigger points(MTrPs)by observing the effects of An-Pressing manipulation on adenosine triphosphate(ATP),adenosine 5′-monophosphate(AMP)-activated protein kinase(AMPK)/peroxisome proliferator-activated receptorγcoactivator 1α(PGC-1α)pathway and mitochondrial ultrastructure of skeletal muscle cells in MTrPs rats.Methods Forty-eight male Sprague-Dawley rats were randomly divided into a blank group,a model group,a lidocaine group,and an An-Pressing manipulation group,with 12 rats in each group.The model group,lidocaine group and An-Pressing manipulation group were used to replicate the MTrPs rat model by blunt shock and centrifugal motion method.After modeling,the An-Pressing manipulation group was subjected to 7 times An-Pressing manipulation,once every other day;the lidocaine group was treated with 3 times of injection of lidocaine at the MTrPs,once every 6 d.The blank group and the model group were fed normally without intervention.After the intervention,local muscle tissue was taken to detect the content of ATP and the expression of AMPK,phosphorylated AMPK(phospho-AMPK),PGC-1α,and glucose transporter 4(GluT4),and the ultrastructure of mitochondria was observed under an electron microscope.Results Compared with the blank group,the ATP content in the model group was decreased(P<0.05),the protein expression levels of phospho-AMPK,PGC-1α,and GluT4 and the ratio of phospho-AMPK to AMPK were decreased(P<0.05);under the electron microscope,the number of mitochondria decreased,and they were deformed,small in volume,and had deformed cristae.Compared with the model group,the ATP contents in the An-Pressing manipulation group and the lidocaine group were increased(P<0.05),and the protein expression levels of phospho-AMPK,PGC-1α,and GluT4 and the ratio of phospho-AMPK to AMPK were increased(P<0.05);under the electron microscope,the number of mitochondria increased,the shape and size of the mitochondria were basically normal,and the cristae could be seen.Compared with the lidocaine group,phospho-AMPK and the ratio of phospho-AMPK to AMPK in the An-Pressing manipulation group were increased(P<0.05);under the electron microscope,the numbers of mitochondria were similar,and the shape and size of the mitochondria were basically normal without swelling,and the cristae could be observed.Conclusion An-Pressing manipulation can increase the ATP content in MTrPs tissue,improve the expression levels of PGC-1α and GluT4 proteins and the ratio of phospho-AMPK to AMPK;its mechanism may relate to the activation of AMPK/PGC-1α signaling pathway to promote the repair of mitochondrial damages.
基金the National Basic Research Program of China(2011CB933201,2012AA022703)the National Natural Science Foundation of China(21222502,91213305)+1 种基金Youth Innovation Promotion Association(CAS),the CAS/SAFEA International Partnership Program for Creative Research Teamsthe“Strategic Priority Research Program”of the Chinese Academy of Sciences(XDA09030305)
文摘Hydrogen sulfide(H_2S)has been found to be the third most important endogenous gaseous signaling molecule after nitric oxide(NO)and carbonic oxide(CO)and plays crucial roles in living organisms and biological systems.Here we use aggregation-induced emission(AIE)of a small organic molecule(TPE-indo)to detect H_2S in both solution and living cells.TPE-indo can target mitochondria and aggregate to fluoresce,which can serve as a sensor for monitoring H_2S in the mitochondria.We regulate the fluorescence of AIE molecules by tuning the viscosity of the solution to form TPE-indo nanoparticles,constructing a probe for H_2S with good selectivity and high sensitivity.The nucleophilic addition of HS-to the TPE-indo is crucial for the rapid H_2S detection.The imaging and analysis of H_2S in mitochondria of living cells with the probe demonstrate potential biological applications.
基金The calculations were performed on the computing facilities of the Consortium deséquipements de Calcul Intensif(CéCI),in particular those of the Plateforme Technologique de Calcul Intensif(PTCI)installed in the University of Namur,for which we gratefully acknowledge financial support of the FNRS-FRFC(2.4.617.07.F,2.5020.11)
文摘Quantum chemical computations have been performed to evaluate the first and second hyperpolarizability quantities of the interference term, linear in the external static electric field, that appear in the electric field-induced sum-frequency generation signal of chiral liquids. These are performed at the time-dependent Hartree-Fock level on the prototypical 1,1′-bi-2-naphtol chiral species.
基金supported by the National Basic Research Program of China(2013CB933701)the National Natural Science Foundation of China(21127901+2 种基金9141311991213305)the Chinese Academy of Science
文摘Single-particle tracking photoactivated local- ization microscopy （sptPALM） has recently emerged as a powerful tool for high-density imaging and tracking of individual molecules in living cells. In this work, we have monitored and compared the diffusion dynamics of TGF-β type II receptor （TβRII） at high expression level using both traditional single-particle tracking （SPT） and sptPALM. The ligand-induced aggregation of TβRII oligomers was further indicated by sptPALM. Due to the capacity of distinguishing and tracking single molecules within diffraction limit, sptPALM outperforms traditional SPT by providing more accurate biophysical information,
基金supported by the National Natural Science Foundation of China (50978087,50978088 and 51039001)the Program for Changjiang Scholars and Innovative Research Team in University (IRT0719)+1 种基金the Hu-nan Provincial Natural Science Foundation of China (10JJ7005)the Hunan Key Scientific Research Project (2009FJ1010)
文摘With the development of colloid interface and enzyme technologies,enzyme-containing reversed micellar system has been receiving much attention in bioseparation and bioconversion. Because of its high efficiency,it has brought new opportunities for the development of molecular biotechnology. Reversed micelles represent nano-sized aqueous droplets stabilized by surfactant amphiphiles inside the bulk organic solvents. The entrapped enzymes have enhanced activities under those conditions as suited in the lipid bilayers of biological membranes. The fundamentals of enzyme-containing reversed micellar system are described in this paper,with special emphasis on the effects of surfactants varying in concentrations and structures. The latest study progress on the surfactants application in enzyme-containing reversed micelles is reviewed. The introduction of novel functional surfactants in micellar enzymology and their future development are also discussed.
