The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer were studied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ions causes a considerable increase of the ge...The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer were studied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ions causes a considerable increase of the gel to liquid crystalline transition temperature of phospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs.展开更多
The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DP...The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DPPC)as templet.All the calcium oxalate c rystals induced by the LB film of DPPC were calcium oxalate monohydrate(COM).However,the morphology of COM was i nfluenced by the additives of C 4 S and L-Glu.C 4 S induced thin and long hexagonal COM c rystals;L-Glu made one or two (010)crystal face of COM crystals dis-appeared.The crystallization time had no effect on the morphology of COM crystals,but the concentration of C 4 S and L-Glu changed it.As increasing the co ncentration of C 4 S,the amount of COM crystals with a hexagonal prism decreased and that with a thin hexago nal slice increased.When the concen tration of C 4 S was 0.50mg ·mL -1 ,all the calcium oxalate crystals were th in hexagonal slice COM crystals.How ever,as the concentration of L-Glu in-creased from 0.01to 0.50mmol·L -1 ,the hexagonal prism-like COM crystals gradually transformed to COM crystals with one or two (010)crystal face disappearance.展开更多
Using a Langmuir-Blodgett film of dipalmitoylphosphatidylcholine(DPPC), a model of biomembranes, as a template, we succeed in obtaining oriented KH 2PO 4(KDP) crystals toward crystal face (100) under well-compressed D...Using a Langmuir-Blodgett film of dipalmitoylphosphatidylcholine(DPPC), a model of biomembranes, as a template, we succeed in obtaining oriented KH 2PO 4(KDP) crystals toward crystal face (100) under well-compressed DPPC monolayer. This is explicable in terms of the geometrical complementarity between KDP and the DPPC monolayer. It is found that the distances between the closest K-K (0.416 nm) fit the d(100) network spacing of DPPC monolayer(0.420 nm), which results in that the special activation energy for nucleation exists in the interface covered with DPPC monolayer. DPPC monolayer has a very strong selected catalysis on the crystallization of KDP crystal face (100), and drives KDP rapid and oriented nucleation on the monolayer/solution interface. The oriented KDP crystals show a good second harmonic generation(SHG) signal.展开更多
Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been appli...Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been applied to study the micellization behaviors of mixed dipalmitoylphosphatidylcholine （DPPC）/hexadecylphosphocholine （HPC） droplets. By vary- ing DPPC/HPC composition and the size of lipid droplets, various micelles such as spherical and nonspherical （oblate or prolate） vesicles, disk-like micelles, double or single ring-like and worm-like micelles were observed. It is found that the lipid droplet as an initial state favors forming vesicles and ring-like micelles due to in situ micellization. Our simulation results demonstrate that using special initial conditions combined with various molecular compositions is an effective way to tune lipid micellar structure.展开更多
On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine （DPPC） and dipalmitoylphosphatidylglycerol （DPPG） in pure phospholipid rnono...On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine （DPPC） and dipalmitoylphosphatidylglycerol （DPPG） in pure phospholipid rnonolayer at the air/water interface during compression are derived. The optimized conformations of phospholipids at absolute freedom state are simulated by Gaussian 98 software. Based on following assumptions： （1） the conformation energy change is mainly caused by the rotation of one special bond; （2） the atoms of glycerol near the water surface are active; （3） the rotation is motivated by hydrogen-bond action; （4） the rotation of bond is inertial, one simplified track of conformational change is suggested and the conformations of DPPC and DPPG at different states are determined by the plots of conformation energy change vs. dihedral angle. The thickness of the simulated phospholipid monolayer is consistent with published experimental result. According to molecular areas at different states, the molecular orientations in the compressing process are also developed.展开更多
Urinary phospholipids are shown to be sensitive biomarkers for kidney injury. Many works have been reported on qualitative analysis of phospholipids and relative components in human urine while quantitative analysis i...Urinary phospholipids are shown to be sensitive biomarkers for kidney injury. Many works have been reported on qualitative analysis of phospholipids and relative components in human urine while quantitative analysis is rare. We have therefore developed a reliable and convenient quantitative method to evaluate the accuracy and specificity of dipalmitoylphosphatidylcholine （DPPC） as a biomarker for kidney injury diagnosis. Chromatographic separation was achieved using a HILIC Silica Column （2.1 ram^50 mm, 5 p.m）. Gradient elution was performed with 5 mM ammonium formate （0.1% formic acid） and acetonitrile （0.1% formic acid）, at a flow rate of 0.3 mL/min. This method was validated in a linear range of 2-200 ng/mL DPPC with inter-day precision of less than 6.5% and accuracy within 111.2% in human urine. Recovery rate, stability, dilution effect and matrix effect also met the requirements for drug evaluation and research issued by FDA. As the first HPLC-MS/MS method for quantitative determination of DPPC, it has been successfully applied to determine levels of DPPC in clinical urine samples and evaluated for potential use in the measurement of DPPC as a biomarker for kidney injury.展开更多
With the extensive applications of rare earth in agriculture, medicament etc., especially the application of Gd-DTPA as nuclear magnetic resonance image reagent in clinical practice, the study of interactive mechanism...With the extensive applications of rare earth in agriculture, medicament etc., especially the application of Gd-DTPA as nuclear magnetic resonance image reagent in clinical practice, the study of interactive mechanism of rare earth in biological body has展开更多
With the wide applications of lanthanide in both industry and agriculture, the mechanism that lanthanide ions are absorbed by organism attracts more and more attention. However, the first issue of the interaction betw...With the wide applications of lanthanide in both industry and agriculture, the mechanism that lanthanide ions are absorbed by organism attracts more and more attention. However, the first issue of the interaction between lanthanide and organism is between lanthanide ions and biological membrane. Thus the study of the interaction between lanthanide ions and biological membrane plays a fundamental role in explaining the physiological effect of lanthanide. In fact the biological membrane is too展开更多
文摘The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer were studied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ions causes a considerable increase of the gel to liquid crystalline transition temperature of phospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs.
文摘The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DPPC)as templet.All the calcium oxalate c rystals induced by the LB film of DPPC were calcium oxalate monohydrate(COM).However,the morphology of COM was i nfluenced by the additives of C 4 S and L-Glu.C 4 S induced thin and long hexagonal COM c rystals;L-Glu made one or two (010)crystal face of COM crystals dis-appeared.The crystallization time had no effect on the morphology of COM crystals,but the concentration of C 4 S and L-Glu changed it.As increasing the co ncentration of C 4 S,the amount of COM crystals with a hexagonal prism decreased and that with a thin hexago nal slice increased.When the concen tration of C 4 S was 0.50mg ·mL -1 ,all the calcium oxalate crystals were th in hexagonal slice COM crystals.How ever,as the concentration of L-Glu in-creased from 0.01to 0.50mmol·L -1 ,the hexagonal prism-like COM crystals gradually transformed to COM crystals with one or two (010)crystal face disappearance.
文摘Using a Langmuir-Blodgett film of dipalmitoylphosphatidylcholine(DPPC), a model of biomembranes, as a template, we succeed in obtaining oriented KH 2PO 4(KDP) crystals toward crystal face (100) under well-compressed DPPC monolayer. This is explicable in terms of the geometrical complementarity between KDP and the DPPC monolayer. It is found that the distances between the closest K-K (0.416 nm) fit the d(100) network spacing of DPPC monolayer(0.420 nm), which results in that the special activation energy for nucleation exists in the interface covered with DPPC monolayer. DPPC monolayer has a very strong selected catalysis on the crystallization of KDP crystal face (100), and drives KDP rapid and oriented nucleation on the monolayer/solution interface. The oriented KDP crystals show a good second harmonic generation(SHG) signal.
基金This work was supported by the National Natural Science Foundation of China （No.20974078 and No.91127046）, Computation was carried out in High Performance Computing Center of Tianjin University.
文摘Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been applied to study the micellization behaviors of mixed dipalmitoylphosphatidylcholine （DPPC）/hexadecylphosphocholine （HPC） droplets. By vary- ing DPPC/HPC composition and the size of lipid droplets, various micelles such as spherical and nonspherical （oblate or prolate） vesicles, disk-like micelles, double or single ring-like and worm-like micelles were observed. It is found that the lipid droplet as an initial state favors forming vesicles and ring-like micelles due to in situ micellization. Our simulation results demonstrate that using special initial conditions combined with various molecular compositions is an effective way to tune lipid micellar structure.
基金Supported by the National Natural Science Foundation of China （20876047）.
文摘On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine （DPPC） and dipalmitoylphosphatidylglycerol （DPPG） in pure phospholipid rnonolayer at the air/water interface during compression are derived. The optimized conformations of phospholipids at absolute freedom state are simulated by Gaussian 98 software. Based on following assumptions： （1） the conformation energy change is mainly caused by the rotation of one special bond; （2） the atoms of glycerol near the water surface are active; （3） the rotation is motivated by hydrogen-bond action; （4） the rotation of bond is inertial, one simplified track of conformational change is suggested and the conformations of DPPC and DPPG at different states are determined by the plots of conformation energy change vs. dihedral angle. The thickness of the simulated phospholipid monolayer is consistent with published experimental result. According to molecular areas at different states, the molecular orientations in the compressing process are also developed.
文摘Urinary phospholipids are shown to be sensitive biomarkers for kidney injury. Many works have been reported on qualitative analysis of phospholipids and relative components in human urine while quantitative analysis is rare. We have therefore developed a reliable and convenient quantitative method to evaluate the accuracy and specificity of dipalmitoylphosphatidylcholine （DPPC） as a biomarker for kidney injury diagnosis. Chromatographic separation was achieved using a HILIC Silica Column （2.1 ram^50 mm, 5 p.m）. Gradient elution was performed with 5 mM ammonium formate （0.1% formic acid） and acetonitrile （0.1% formic acid）, at a flow rate of 0.3 mL/min. This method was validated in a linear range of 2-200 ng/mL DPPC with inter-day precision of less than 6.5% and accuracy within 111.2% in human urine. Recovery rate, stability, dilution effect and matrix effect also met the requirements for drug evaluation and research issued by FDA. As the first HPLC-MS/MS method for quantitative determination of DPPC, it has been successfully applied to determine levels of DPPC in clinical urine samples and evaluated for potential use in the measurement of DPPC as a biomarker for kidney injury.
基金Project supported by the National Natural Science Foundation of China
文摘With the extensive applications of rare earth in agriculture, medicament etc., especially the application of Gd-DTPA as nuclear magnetic resonance image reagent in clinical practice, the study of interactive mechanism of rare earth in biological body has
文摘With the wide applications of lanthanide in both industry and agriculture, the mechanism that lanthanide ions are absorbed by organism attracts more and more attention. However, the first issue of the interaction between lanthanide and organism is between lanthanide ions and biological membrane. Thus the study of the interaction between lanthanide ions and biological membrane plays a fundamental role in explaining the physiological effect of lanthanide. In fact the biological membrane is too
