The Experts below are selected from a list of 645 Experts worldwide ranked by ideXlab platform
Marian Góral - One of the best experts on this subject based on the ideXlab platform.
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Vapour-liquid equilibria in non-polar mixtures. III. Binary mixtures of alkylbenzenes and n-alkanes at 313.15 K
Fluid Phase Equilibria, 1994Co-Authors: Marian GóralAbstract:Abstract Total vapour pressure measurements made by a modified static method for the binary systems of benzene, toluene, ethylbenzene and p -xylenene with n -hexane, n -heptane, n -octane and n -decane at 313.15 K are reported. The results were correlated with four Equations for excess Gibbs energy. Comparison of their correlating ability was made. Agreement with literature data was checked. Experimental results were compared with prediction by the UNIFAC method and with the Hildebrand-Scatchard Equation.
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Vapour-liquid equilibria in nonpolar mixtures: Part I. 2,2,4-trimethylpentane with benzene, toluene, o-xylene, pxylene, ethylbenzene and propylbenzene at 313.15 K
Fluid Phase Equilibria, 1993Co-Authors: Marian Góral, Nazira AsmanovaAbstract:Abstract Goral, M. and Asmanova, N., 1993. Vapour-liquid equilibria in nonpolar mixtures. Part I. 2,2,4-Trimethylpentane with benzene, toluene, o-xylene, p-xylene, ethylbenzene and pro-pylbenzene at 313.15 K. Fluid Phase Equilibria, 86: 201-209 Total vapour pressure measurements made by a modified static method at 313.15 K are reported for binary mixtures of 2,2,4-trimethylpentane with benzene, toluene, ethylbenzene, o-xylene, p-xylene and propylbenzene. A correlation with various Equations for excess Gibbs energy is discussed. A comparison has been made with literature data. A comparison with predictions by the UNIFAC method and with the Hildebrand-Scatchard Equation was also carried out.
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Vapour-liquid equilibria in nonpolar mixtures: II. Carbon tetrachloride with alkylbenzenes and n-alkanes at 313.15 K
Fluid Phase Equilibria, 1993Co-Authors: Marian Góral, S. ZawadzkiAbstract:Abstract Goral, M. and Zawadzki, S., 1993. Vapour-liquid equilibria in nonpolar mixtures. II. Carbon tetrachloride with alkylbenzenes and n-alkanes at 313.15 K. Fluid Phase Equilibria, 90: 355-364. Total vapour pressure measurements using a modified static method at 313.15 K are reported for binary mixtures of CCl4 with benzene, toluene, o-xylene, p-xylene, hexane, heptane, octane, nonane and decane. The results were correlated with the generalized Redlich-Kister Equation for excess Gibbs energy. A comparison with literature vapour-liquid equilibrium data and excess enthalpy was made. Consistency within homologous series was checked. Predictions made using the UNIFAC method and the Hildebrand-Scatchard Equation were compared.
Xingguo Chen - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the interaction between endocrine disruptor bisphenol A and human serum albumin
Chemosphere, 2010Co-Authors: Xiaoyun Xie, Xiaoru Wang, Huijun Sun, Xingguo ChenAbstract:Abstract In this study, the interaction of the endocrine disruptor bisphenol A (BPA) and human serum albumin (HSA) was investigated by molecular modelling, fluorescence, ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR) and circular dichroism spectroscopy (CD). The association constants between BPA and HSA were determined using the Scatchard Equation. The thermodynamic parameters of the binding reaction (ΔG0, ΔH0 and ΔS0) were measured, and they indicated the presence of hydrophobic forces in the BPA–HSA interaction, which agreed well with the results from molecular modelling. The alterations of protein secondary structure in the presence of BPA were confirmed by UV–vis, FT-IR and CD spectroscopy. Lastly, the average binding distance, r, between BPA and HSA was evaluated and found to be 1.82 nm according to Forster’s theory of non-radiation energy transfer.
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Flow injection-capillary electrophoresis frontal analysis method for the study of the interactions of a series of drugs with human serum albumin.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2009Co-Authors: Xiumei Liu, Jingshu Zhang, Xingguo ChenAbstract:In this paper, a fast method for the study on the interactions of a series of drugs used in the treatment of hypertension with human serum albumin (HSA) by flow injection-capillary electrophoresis (FI-CE) was developed based on the principle of frontal analysis (FA). The binding parameters were determined by FI-CE-FA from Scatchard Equation and compared with results obtained by non-CE methods and literature values. A multiple linear regression (MLR) model between the drug-protein binding constants (K) and structural descriptors of drugs was constructed. L-tryptophan (L-try) and phenylbutazone (PB) were used as displacement reagents to investigate the binding sites of a series of drugs on HSA. The binding synergism effect between drugs and the effects of many metal ions existing in human plasma on protein binding were also investigated systematically.
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characterization of the mangiferin human serum albumin complex by spectroscopic and molecular modeling approaches
Journal of Pharmaceutical and Biomedical Analysis, 2009Co-Authors: Xingguo ChenAbstract:Abstract The interactions between mangiferin and human serum albumin (HSA) were investigated by spectroscopy and molecular modeling. The results proved the formation of complex between mangiferin and HSA. Hydrophobic interaction dominated in the association reaction. Mangiferin statically quenched the fluorescence of HSA in a concentration dependent manner positively deviating from the linear Scatchard Equation. The binding of mangiferin to HSA lead to changes in the conformation of HSA according to synchronous fluorescence spectra, FT-IR, UV–vis and CD data. The presence of amino acids and metal ion affected the binding constant of mangiferin–HSA complex. Computational mapping of the possible binding sites of mangiferin revealed the molecule to be bound in the large hydrophobic cavity of subdomain IIA.
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interaction of rhein with human serum albumin investigation by optical spectroscopic technique and modeling studies
Biochimica et Biophysica Acta, 2007Co-Authors: Xiaojun Yao, Jing Jin, Xingguo ChenAbstract:Abstract The binding of rhein with human serum albumin (HSA) has been studied in detail by spectroscopic method including circular dichroism (CD), Fourier transformation infrared spectra (FT-IR), fluorescence spectra. The binding parameters for the reaction have been calculated according to Scatchard Equation at different temperatures. The plots indicated that the binding of HSA to rhein at 303, 310 and 318 K is characterized by one binding site with the affinity constant K at (4.93 ± 0.16) × 105, (4.02 ± 0.16) × 105 and (2.69 ± 0.16) × 105 M-1, respectively. The secondary structure compositions of free HSA and its rhein complexes were estimated by the FT-IR spectra. FT-IR and curve-fitted results of amide I band are in good agreement with the analyses of CD spectra. Molecular Modeling method was used to calculate the interaction modes between the drug and HSA.
Yu Ou-yang - One of the best experts on this subject based on the ideXlab platform.
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Biophysical studies on the interactions of jatrorrhizine with bovine serum albumin by spectroscopic and molecular modeling methods.
Molecular biology reports, 2013Co-Authors: Xiao-yang Fan, Yu Ou-yangAbstract:The interaction between jatrorrhizine (JAT) and bovine serum albumin (BSA) has been studied. The studies were carried out in a buffer medium at pH 7.4 using fluorescence spectroscopy, UV–vis spectroscopy, and molecular modeling methods. The results of fluorescence quenching and UV–vis absorption spectra experiments indicated the formation of the complex of BSA–JAT. Binding parameters were determined using the Stern–Volmer Equation and Scatchard Equation. The results of thermodynamic parameters ΔG, ΔH and ΔS at different temperatures indicate that the electrostatic interactions and hydrogen bonds play a major role for JAT–BSA association. Site marker competitive displacement experiments and molecular modeling calculation demonstrating that JAT is mainly located within the hydrophobic pocket of the subdomain IIIA of BSA. Furthermore, The distance between donor (BSA) and acceptor (JAT) was estimated according to fluorescence resonance energy transfer.
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Determination of the specific interaction between palmatine and bovine serum albumin.
Molecular biology reports, 2011Co-Authors: Yu Ou-yang, Hong Wang, Min FangAbstract:The binding of palmatine to bovine serum albumin (BSA) was studied under physiological conditions (pH = 7.40) by molecular spectroscopic approach. It was proved that the fluorescence quenching of BSA by palmatine is a result of the formation of palmatine–BSA complex. Binding parameters were determined using the modified Stern–Volmer Equation and Scatchard Equation, to measure the specific binding between palmatine and BSA. The thermodynamic parameters calculated, ∆G°, ∆H° and ∆S° indicate that the electrostatic interactions play a major role in the palmatine–BSA association. Site marker competitive displacement experiments demonstrated that palmatine binds with specific affinity to site II (subdomain IIIA) of BSA. Furthermore, the specific binding distance r (3.36 nm) was obtained according to fluorescence resonance energy transfer. The results of synchronous fluorescence spectra and UV–Visible absorption spectra show that the conformation of bovine serum albumin has been changed.
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Affinity and specificity of ciprofloxacin-bovine serum albumin interactions: spectroscopic approach.
The protein journal, 2010Co-Authors: Yu Ou-yang, Yue Zhang, Yi LiuAbstract:Fluorescence spectroscopy in combination with UV–Vis absorption spectroscopy were employed to investigate the binding of an antibacterial drug Ciprofloxacin (CPFX) to bovine serum albumin (BSA) under the physiological conditions. In the discussion of the quenching mechanism, it was proved that the fluorescence quenching of BSA by CPFX is a result of the formation of CPFX-BSA complex. Binding parameters were determined using the modified Stern-Volmer Equation and Scatchard Equation to provide a measure of the binding affinity between CPFX and BSA. The results of thermodynamic parameters ΔG, ΔH, ΔS, at different temperatures indicate that the electrostatic interactions play a major role for CPFX-BSA association. Site marker competitive experiments indicated that the binding of CPFX to BSA primarily took place in site I. Furthermore, the effect of metal ions to CPFX-BSA system was studied, and the distance r between donor (BSA) and acceptor (CPFX) was obtained according to fluorescence resonance energy transfer (FRET). The conformation of BSA upon CPFX binding was evaluated by measuring synchronous fluorescence properties of the CPFX-BSA complex.
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Binding of berberine to bovine serum albumin: spectroscopic approach.
Molecular biology reports, 2010Co-Authors: Yu Ou-yang, Chun-mei Dai, Yi Liu, Xiao-he XiaoAbstract:Fluorescence spectroscopy in combination with UV-vis absorption spectroscopy was employed to investigate the binding of an important traditional medicinal herb berberine to bovine serum albumin (BSA) under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by berberine is a result of the formation of berberine-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer Equation and Scatchard Equation to provide a measure of the binding affinity between berberine and BSA. The results of thermodynamic parameters ΔG, ΔH, ΔS at different temperatures indicate that the electrostatic interactions play a major role for berberine-BSA association. Site marker competitive experiments indicated that the binding of berberine to BSA primarily took place in site II. Furthermore, the Effect of supramolecules to berberine-BSA system, and the distance r between donor (BSA) and acceptor (berberine) was obtained according to fluorescence resonance energy transfer (FRET).
Yifan Jiang - One of the best experts on this subject based on the ideXlab platform.
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Preparation and Properties of Ginsenoside Rg1 Molecularly Imprinted Polymers
Advanced Materials Research, 2012Co-Authors: Xiao Ying Yin, Yifan Jiang, Qing Shan LiuAbstract:Molecularly imprinted polymers (MIPs) were prepared by precipitation polymerization with ginsenoside Rg1 as the template molecule. The morphology of MIPs was characterized by scanning electronmicroscope (SEM) and its static adsorption capacity was measured by the Scatchard Equation. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The application of MIPs with high affinity toward the template molecule might offer a novel method for the enrichment and determination of active compounds in the traditional herbal medicine.
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A Novel Method for Preparing the Surface Molecularly Imprinted Polymers to Target Isolate Ginsenoside Rg1 and its Analogues
Advanced Materials Research, 2012Co-Authors: Qing Shan Liu, Qiu Juan Wang, Qing Long Guo, Yifan Jiang, Xiao Ying YinAbstract:To establish a novel method for preparing molecularly imprinted polymers for ginsenoside Rg1 with better character contrast to previous studies, we have prepared novel surface molecular imprinted polymers (S-MIPs) using ginsenoside Rg1 as the template molecule, Acrylamide (AM) as the functional monomer, and silica gel as the carrier. The morphology of S-MIPs was characterized by scanning electron microscope (SEM) and its static adsorption capacity was measured by the Scatchard Equation.
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development of andrographolide molecularly imprinted polymer for solid phase extraction
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011Co-Authors: Yifan JiangAbstract:Abstract A method employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE) to pretreat samples was developed. The polymers were prepared by precipitation polymerization with andrographolide as template molecule. The structure of MIP was characterized and its static adsorption capacity was measured by the Scatchard Equation. In comparison with C18-SPE and non-imprinted polymer (NIP) SPE column, MIP-SPE column displays high selectivity and good affinity for andrographolide and dehydroandrographolide for extract of herb Andrographis paniculata (Burm.f.) Nees (APN). MIP-SPE column capacity was 11.9 ± 0.6 μmol/g and 12.1 ± 0.5 μmol/g for andrographolide and dehydroandrographolide, respectively and was 2–3 times higher than that of other two columns. The precision and accuracy of the method developed were satisfactory with recoveries between 96.4% and 103.8% (RSD 3.1–4.3%, n = 5) and 96.0% and 104.2% (RSD 2.9–3.7%, n = 5) for andrographolide and dehydroandrographolide, respectively. Various real samples were employed to confirm the feasibility of method. This developed method demonstrates the potential of molecularly imprinted solid phase extraction for rapid, selective, and effective sample pretreatment.
Changsheng Zhao - One of the best experts on this subject based on the ideXlab platform.
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Designing a Photoresponsive Molecularly Imprinted System on a Silicon Wafer Substrate Surface
Langmuir : the ACS journal of surfaces and colloids, 2013Co-Authors: Dongsheng Wang, Danyang Xie, Wenbin Shi, Shudong Sun, Changsheng ZhaoAbstract:A photoresponsive molecularly imprinted system was prepared on a silicon wafer substrate surface via the host–guest complex of grafted 4-(3-triethoxysilylpropyiureido)azobenzene (TSUA) and mono-6-deoxy-6-((p-chlorosulfonyl)-benzoic acid)-β-cyclodextrin (CBA−β-CD), and the acid–base pair interactions/hydrogen bonds between CBA−β-CD and the template molecules, including theophylline (TPE) and 4-hydroxybenzoic acid (4-HA). A molecular imprinting cycle “imprinting → extracting → uptaking → shuffling” was also defined in the study, the processes of uptaking and shuffling were investigated in detail by equilibrium binding experiments, and the Langmuir adsorption isotherm and Scatchard Equation were used to evaluate the binding affinity and the theoretical binding sites of the molecularly imprinted (MIS), nonimprinted (NIS), and pure (PS) silicon wafer substrates. Compared with the NISs and PSs, the MISs showed a significantly higher adsorption capacity for the template molecules. More importantly, the MISs show...
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Designing a Photoresponsive Molecularly Imprinted System on a Silicon Wafer Substrate Surface
2013Co-Authors: Dongsheng Wang, Danyang Xie, Wenbin Shi, Shudong Sun, Changsheng ZhaoAbstract:A photoresponsive molecularly imprinted system was prepared on a silicon wafer substrate surface via the host–guest complex of grafted 4-(3-triethoxysilylpropyiureido)azobenzene (TSUA) and mono-6-deoxy-6-((p-chlorosulfonyl)-benzoic acid)-β-cyclodextrin (CBA−β-CD), and the acid–base pair interactions/hydrogen bonds between CBA−β-CD and the template molecules, including theophylline (TPE) and 4-hydroxybenzoic acid (4-HA). A molecular imprinting cycle “imprinting → extracting → uptaking → shuffling” was also defined in the study, the processes of uptaking and shuffling were investigated in detail by equilibrium binding experiments, and the Langmuir adsorption isotherm and Scatchard Equation were used to evaluate the binding affinity and the theoretical binding sites of the molecularly imprinted (MIS), nonimprinted (NIS), and pure (PS) silicon wafer substrates. Compared with the NISs and PSs, the MISs showed a significantly higher adsorption capacity for the template molecules. More importantly, the MISs showed a reimprinted ability; after the process of shuffling, the molecularly imprinted systems on the substrate surface were destroyed, and new imprinted systems could be fabricated for the recognition of other template molecules after washing the substrates under irradiation at 450 nm. Moreover, the selective adsorption for the MISs was investigated, which indicated that the MISs showed specific affinity to the template molecules (TPE or 4-HA)
