The fluorescence spectrum of the ether-water solution excited by the ultraviolet light with the wavelength of 245 nm is experimentally detected. Based on the second derivative analysis, the fluorescence spectrum of th...The fluorescence spectrum of the ether-water solution excited by the ultraviolet light with the wavelength of 245 nm is experimentally detected. Based on the second derivative analysis, the fluorescence spectrum of the ether-water solution is used as Gaussian decomposition and seven Gaussian spectral lines are obtained. The center wavelength, the peak intensity and the half peak bandwidth of each Gaussian spectral line are measured, and the multi-peak fitting is made by using Gaussian primitive parameters. The highest and the lowest oscillation energy level differences in the ground state of each Gaussian spectrum are calculated. It is found that there are seven types of luminescent association molecules formed by ether and water molecules in different configurations existed in the solution. The location of each optimum absorption wavelength and the half peak bandwidth of the Gaussian spectral line is different. The energy level difference with the central wavelength of 304 nm attains the maximum value The result can contribute to the study of the molecular association in ether-water solution.展开更多
Objective To explore the effects of SDS, PBS re-dissolvent solutions on fluorescence values of radioallergosorbent test (RAST) inhibition. Methods Dermatophagoides pterronyssinus allergen immunoCAP and UniCAP 100 Syst...Objective To explore the effects of SDS, PBS re-dissolvent solutions on fluorescence values of radioallergosorbent test (RAST) inhibition. Methods Dermatophagoides pterronyssinus allergen immunoCAP and UniCAP 100 System were used. The Sera Pool consisted of 20 Dermatophagoides pterronyssinus allergic patients sera, their specific IgE fluorescence values were between 12 505 and 24 776. Results Fluorescence value percentages decreased: 62.9%, 54.1%, 43.5%, 6.7%, 3.7%, 2.6%, 2.2%, and 1.4% respectively, when SDS concentrations were at 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, 0.025%, and 0.01%. Fluorescence values decreased more than 5% with SDS concentrations equal to 0.25% or higher. PBS in 0.1 and 0.01 mol/L concentrations decreased fluorescence values 2.9% and 0.9% respectively. Conclusions SDS is a commonly used surfactants in allergen extract and re-dissolvent prepared allergen precipitation for RAST inhibition. Thus effects of surfactants (e.g. SDS) upon the RAST inhibition tests must be considered when they were used as re-dissolvent agents to improve protein resolution in RAST inhibition.展开更多
The fluorescent carbon dots were successfully synthesized by simply heating the mixture of lactose and Na OH solution. The as-synthesized carbon dots had been systematically characterized by fluorescence, Fourier tran...The fluorescent carbon dots were successfully synthesized by simply heating the mixture of lactose and Na OH solution. The as-synthesized carbon dots had been systematically characterized by fluorescence, Fourier transform infrared(FTIR), high resolution transmission electron microscopy(HR-TEM) and ^(13)C NMR. Since the fluorescence of the carbon dots was efficiently quenched by folic acid, the carbon dots were employed as selective fluorescence probes for detecting folic acid, depending on the formation of hydrogen bond among the functional group of folic acid(–OH, –COOH and –NH_2) and –OH and –COOH of the carbon dots. Moreover, the decrease of fluorescence intensity was capable of detecting folic acid in a linear range of 6×10^(-5)–8×10^(-8) mol/L with a detection limit of 1.2×10^(-9)mol/L at a signal-to-noise ratio of 3, suggesting a promising assay for folic acid. Significantly, the practicability of this fluorescence probe to assay folic acid in human urine samples was further evaluated.展开更多
We report a novel strategy to study the chain dynamics of poly(acrylic acid) (PAA) in a relative concentrated solution (1.0 g/L). The strategy is based on the fluorescent probe (DCTPE) with unique aggregation-induced ...We report a novel strategy to study the chain dynamics of poly(acrylic acid) (PAA) in a relative concentrated solution (1.0 g/L). The strategy is based on the fluorescent probe (DCTPE) with unique aggregation-induced emission (AIE) characteristics. Free DCTPE molecules are non-emissive in aqueous solution, but they become highly emissive when trapped in polymer coils. The fluorescence intensity is proportional to the efficiency of trapping DCTPE molecules in polymer coils. By correlation the change of fluorescence intensity with the variation of pH value (from 1.78 to 12.06), the PAA chain's dynamics in the relatively concentrated solution have been elucidated into three processes. In the pH range from 12.06 to 6.0, PAA chains take an extended and non-folding conformation. Changing pH from 6.0 to 3.86, PAA chains are partially protonated and loosely packed polymer coils are formed. Further lowering the pH value of the solution (from 3.86 to 1.78), protonated segments dominate the PAA chains, and at the same time, the intermolecular hydrogen bonding takes effect, thus the polymer chains posses in the conformation of more compact coils.展开更多
Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demons...Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demonstrated.These two dyes have a major advantage that efficient fluorescence quenching can be observed even in their dilute solutions.A comparison of photophysical properties between the dimeric QA cyclophane and its reference monomeric counterpart indicates that the dimerization is predominant for the fluorescence quenching of QA dyes in solution.This study provided some model QA derivatives with dimeric structures for understanding the fluorescence quenching of QA dyes in solutions.展开更多
基金Supported by the Natural Science Foundation of Jiangsu Province(BK2007204)the Natural Sci-ence Foundation of Educational Department of Jiangsu Province(07KJD140208)~~
文摘The fluorescence spectrum of the ether-water solution excited by the ultraviolet light with the wavelength of 245 nm is experimentally detected. Based on the second derivative analysis, the fluorescence spectrum of the ether-water solution is used as Gaussian decomposition and seven Gaussian spectral lines are obtained. The center wavelength, the peak intensity and the half peak bandwidth of each Gaussian spectral line are measured, and the multi-peak fitting is made by using Gaussian primitive parameters. The highest and the lowest oscillation energy level differences in the ground state of each Gaussian spectrum are calculated. It is found that there are seven types of luminescent association molecules formed by ether and water molecules in different configurations existed in the solution. The location of each optimum absorption wavelength and the half peak bandwidth of the Gaussian spectral line is different. The energy level difference with the central wavelength of 304 nm attains the maximum value The result can contribute to the study of the molecular association in ether-water solution.
基金Supported by a grantfrom the Ministryof Science and Technology PRC (2003AA2Z3502 ).
文摘Objective To explore the effects of SDS, PBS re-dissolvent solutions on fluorescence values of radioallergosorbent test (RAST) inhibition. Methods Dermatophagoides pterronyssinus allergen immunoCAP and UniCAP 100 System were used. The Sera Pool consisted of 20 Dermatophagoides pterronyssinus allergic patients sera, their specific IgE fluorescence values were between 12 505 and 24 776. Results Fluorescence value percentages decreased: 62.9%, 54.1%, 43.5%, 6.7%, 3.7%, 2.6%, 2.2%, and 1.4% respectively, when SDS concentrations were at 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, 0.025%, and 0.01%. Fluorescence values decreased more than 5% with SDS concentrations equal to 0.25% or higher. PBS in 0.1 and 0.01 mol/L concentrations decreased fluorescence values 2.9% and 0.9% respectively. Conclusions SDS is a commonly used surfactants in allergen extract and re-dissolvent prepared allergen precipitation for RAST inhibition. Thus effects of surfactants (e.g. SDS) upon the RAST inhibition tests must be considered when they were used as re-dissolvent agents to improve protein resolution in RAST inhibition.
基金supported by the Science Foundation of Southwest University (SWU114053)the Natural Science Foundation Project of CQ CSTC (cstc2013jcyj A10117)+1 种基金the Fundamental Research Funds for the Central Universities (XDJK2015A005, XDJK2016D033)the Innovative Research Project for Postgraduate Students of Chongqing (CYS14049)
文摘The fluorescent carbon dots were successfully synthesized by simply heating the mixture of lactose and Na OH solution. The as-synthesized carbon dots had been systematically characterized by fluorescence, Fourier transform infrared(FTIR), high resolution transmission electron microscopy(HR-TEM) and ^(13)C NMR. Since the fluorescence of the carbon dots was efficiently quenched by folic acid, the carbon dots were employed as selective fluorescence probes for detecting folic acid, depending on the formation of hydrogen bond among the functional group of folic acid(–OH, –COOH and –NH_2) and –OH and –COOH of the carbon dots. Moreover, the decrease of fluorescence intensity was capable of detecting folic acid in a linear range of 6×10^(-5)–8×10^(-8) mol/L with a detection limit of 1.2×10^(-9)mol/L at a signal-to-noise ratio of 3, suggesting a promising assay for folic acid. Significantly, the practicability of this fluorescence probe to assay folic acid in human urine samples was further evaluated.
基金the National Science Foundation of China (21074113)the Key Project of the Natural Science Foundation of Zhejiang Province (Z4110056)
文摘We report a novel strategy to study the chain dynamics of poly(acrylic acid) (PAA) in a relative concentrated solution (1.0 g/L). The strategy is based on the fluorescent probe (DCTPE) with unique aggregation-induced emission (AIE) characteristics. Free DCTPE molecules are non-emissive in aqueous solution, but they become highly emissive when trapped in polymer coils. The fluorescence intensity is proportional to the efficiency of trapping DCTPE molecules in polymer coils. By correlation the change of fluorescence intensity with the variation of pH value (from 1.78 to 12.06), the PAA chain's dynamics in the relatively concentrated solution have been elucidated into three processes. In the pH range from 12.06 to 6.0, PAA chains take an extended and non-folding conformation. Changing pH from 6.0 to 3.86, PAA chains are partially protonated and loosely packed polymer coils are formed. Further lowering the pH value of the solution (from 3.86 to 1.78), protonated segments dominate the PAA chains, and at the same time, the intermolecular hydrogen bonding takes effect, thus the polymer chains posses in the conformation of more compact coils.
基金supported by the National Natural Science Foundation of China (50773027 & 50903037)
文摘Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demonstrated.These two dyes have a major advantage that efficient fluorescence quenching can be observed even in their dilute solutions.A comparison of photophysical properties between the dimeric QA cyclophane and its reference monomeric counterpart indicates that the dimerization is predominant for the fluorescence quenching of QA dyes in solution.This study provided some model QA derivatives with dimeric structures for understanding the fluorescence quenching of QA dyes in solutions.
