H pylori is etiologically associated with gastritis, gas-tric and duodenal ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Eradicating H pylori may convert rapidly the outcome of ...H pylori is etiologically associated with gastritis, gas-tric and duodenal ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Eradicating H pylori may convert rapidly the outcome of related diseases with the use of more accurate diagnostic molecular tests. Indeed some of the tests cannot give the evidence of current infection; H pylori can be detected by noninvasive and invasive methods, the latter requiring an endoscopy. Eradication failure is a big problem in H pylori infection. Recently, clarithromycin resistance in H pylori strains is increasing and eradicati-on therapy of this bacterium is becoming more difficult. Molecular methods have frequently been applied besides phenotypic methods for susceptibility testing to detect clarithromycin resistance due to mutations in the 2143 and 2144 positions of 23S rRNA gene. Fluorescence in situ hybridization (FISH) method on paraffin embedded tissue is a rapid, accurate and cost-effective method for the detection of H pylori infection and to determine clarithromycin resistance within three hours according to the gold standards as a non-culture method. This method can also be applied to fresh biopsy samples and the isolated colonies from a culture of H pylori, detecting both the culturable bacillary forms and the coccoid forms of H pylori, besides the paraffin embedded tissue secti-ons. This technique is helpful for determining the bac-terial density and the results of treatment where clarith-romycin has been widely used in populations to increase the efficacy of the treatment and to clarify the treatment failure in vitro.展开更多
Recently,the simplified spherical harmonics equations(SP)model has at tracted much att entionin modeling the light propagation in small tissue ggeometriesat visible and near-infrared wave-leng ths.In this paper,we rep...Recently,the simplified spherical harmonics equations(SP)model has at tracted much att entionin modeling the light propagation in small tissue ggeometriesat visible and near-infrared wave-leng ths.In this paper,we report an eficient numerical method for fluorescence moleeular tom-ography(FMT)that combines the advantage of SP model and adaptive hp finite elementmethod(hp-FEM).For purposes of comparison,hp-FEM and h-FEM are,respectively applied tothe reconstruction pro cess with diffusion approximation and SPs model.Simulation experiments on a 3D digital mouse atlas and physical experiments on a phantom are designed to evaluate thereconstruction methods in terms of the location and the reconstructed fluorescent yield.Theexperimental results demonstrate that hp-FEM with SPy model,yield more accurate results thanh-FEM with difusion approximation model does.The phantom experiments show the potentialand feasibility of the proposed approach in FMT applications.展开更多
Heteroatom doping is an efficient approach to regulate the fluorescence properties of carbon dots.Using aminophenylboronic acid as the raw material,a combustion method was developed for the synthesis of boron,nitrogen...Heteroatom doping is an efficient approach to regulate the fluorescence properties of carbon dots.Using aminophenylboronic acid as the raw material,a combustion method was developed for the synthesis of boron,nitrogen-doped carbon dots（B,N-carbon dots）.The B,N-carbon dots emitted green fluorescence and displayed high resistance to both photo bleaching and ionic strength.A facile fluorescence sensing approach for Cu^2＋ was fabricated via static fluorescence quenching.Under optimal conditions,a rapid detection of Cu^2＋ could be completed in 2 min with a linearity ranging from 1 μmol/L to 25 μmol/L and a detection limit of 0.3 μmol/L Furthermore,the proposed method showed potential applications for the detection of Cu^2＋ in natural water samples.展开更多
A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of...A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented.展开更多
Based on a previous research of cavitation effect under bi-frequency ultrasound irradiation, this paper studies bi-frequency irradiations with similar experimental settings. The additional irradiation sources with fre...Based on a previous research of cavitation effect under bi-frequency ultrasound irradiation, this paper studies bi-frequency irradiations with similar experimental settings. The additional irradiation sources with frequencies of 1.04MHz, 0.8MHz and 1.7MHz are individually combined with the main ultrasonic irradiation source with frequency of 28kHz to form bi-frequency ultrasonic irradiation. The intensity of 28kHz irradiation was fixed at 12.5W/cm^2, while the intensity of the ultrasound at the other three frequencies is varied from1 W/cm^2 to 18 W/cm^2. It turns out that under the influence of the bi-frequency irradiation, the fluorescence intensity is obviously greater than the sum of those at individual frequencies. So the frequency of the additional sonication strikingly influences the fluorescence enhancement effect. For example, the fluorescence enhancement effect of 1.04MHz is stronger than that of 1.7MHz, and the enhancement effect of 0.8MHz is further stronger than that of 1.04MHz. Under the sonic intensity of (7.9)W/cm^2, the fluorescence intensity of 1.04MHz is approximately twice that of 1.7MHz while the fluorescence intensity of 0.8MHz is approximately 1.5 times that of 1.04MHz.展开更多
The state of Tb3+ is investigated in liposome. When the concentration of PC is below CMC (critical micell concentration), most of Tb3+ is associated with PC, the binding constant is about 3.35×103 L/mol. When the...The state of Tb3+ is investigated in liposome. When the concentration of PC is below CMC (critical micell concentration), most of Tb3+ is associated with PC, the binding constant is about 3.35×103 L/mol. When the concentration of PC is beyond CMC, most of Tb3+ is dimerized, the dimerization constant is about 3.92×104L/mol. In PC?CH?H2O system, the binding constant of Tb3+?CH complex 2.93×104L/mol is obtained.展开更多
Fura-2 was first used to monitor intracellular RE(3+). The characterizations of RE3+-Fura-2 interactions in solutions simulating intracellular ionic composition show that La3+ and Y3+ both form 1:1 RE(3+)-fura-2 compl...Fura-2 was first used to monitor intracellular RE(3+). The characterizations of RE3+-Fura-2 interactions in solutions simulating intracellular ionic composition show that La3+ and Y3+ both form 1:1 RE(3+)-fura-2 complexes. The apparent dissociation constants are 1.61×10(-7)M,and 4.04×10(-7)M,respectively. The mouse myeloma(SP2/0) cells exposed to free RE(3+) or free RE(3+) and some small molecules in body were Studied by single cell canon measurement system.The results support the assumption that RE(3+) ions cannot enter the cytoplasm of living cells, and the small molecules used in our experiments couldn't improve the permeability of RE(3+)ions.展开更多
New HPLC method was developed for determination of amlodipine and valsartan in their binary mixture as a part of routine control of combined formulations. The method was validated to meet official requirements includi...New HPLC method was developed for determination of amlodipine and valsartan in their binary mixture as a part of routine control of combined formulations. The method was validated to meet official requirements including selectivity, stability, linearity, precision and accuracy. Chromatography was carried out using a LiChrospher RP-18 column, a mixture containing acetonitrile, phosphate buffer of pH 3.5 and methanol (45:45:10, v/v/v) and new fluorescence detection at 255 nm for excitation and 448 nm for emission. The effect of methanol content, pH of the buffer, flow rate, detection wavelengths and column temperature was estimated in robustness study, according to a plan defined by the Plackett-Burman design. For identification of significant effects, both graphical and statistical methods were used. Ro-bustness for dissolution test was checked estimating the effects of paddle speed, temperature and pH of dissolution medium. The method was proved to complying with all official guidelines. Therefore, it is suitable for determination of amlodipine and valsartan in their binary mixtures for different analytical and pharmaceutical purposes.展开更多
The amorphous I/Au composite nanofilms were prepared by low vacuum direct current sputtering(LVDCS)method.The optimized preparation technologies contain growth pressure,time,gaseous environment and annealing condition...The amorphous I/Au composite nanofilms were prepared by low vacuum direct current sputtering(LVDCS)method.The optimized preparation technologies contain growth pressure,time,gaseous environment and annealing conditions.The maximum fluorescence emission(λemmax)of I/Au nanofilms was observed at wavelength of 375 nm,and the intensity of fluorescence emission peak of annealed I/Au films was smaller than that of unannealed one due to fewer amorphous Au nanoparticles,caused by annealing treatment.In the UV-Vis absorption spectra,the intensity of UV-Vis absorption peak of annealed I/Au nanofilms is larger than that of the unannealed one.This work also developed a new way to grow I/Au composite fluorescent thin films.展开更多
[Objectives]To establish a new method for indirect determination of bisoprolol fumarate based on fluorescence quenching technology.[Methods]In ammonia water and ammonium chloride buffer solution at pH=9.2,whenλexcita...[Objectives]To establish a new method for indirect determination of bisoprolol fumarate based on fluorescence quenching technology.[Methods]In ammonia water and ammonium chloride buffer solution at pH=9.2,whenλexcitation=277 nm andλemission=596 nm,with the increase of CCu2+,the fluorescence signal intensity of bisoprolol fumarate weakened,and the difference between the fluorescence intensity of bisoprolol fumarate itself and the fluorescence intensity of the test solution after the quencher Cu2+was added(ΔF)and Cbisoprolol fumarate showed a good linear relationship.[Results]In the range of 15.39-76.93μg/mL,ΔF=146.7 Cbisoprolol fumarate+482.1,r=0.9988,and the detection limit is 0.1391μg/mL.[Conclusions]The fluorescence quenching method has been applied to the determination of actual samples with a recovery rate of 99.9%and an RSD of 2.7%.The results are satisfactory.展开更多
In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming...In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming process;therefore,this work introduces an automatic focusing method for Soller slits in multi-element fluorescence detectors.This method establishes a relation model between the fluorescence intensity distribution and the coordinates of the fluorescence excitation point.According to this relation model,the actual coordinates of the fluorescence excitation point can be deduced from the detected fluorescence intensity distribution and used in focusing operations.This method has proven to be feasible in an XAFS experiment at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility.展开更多
A fluoroimmunoassay method using unlabeled europium chelate is described.The principle is similar to that of fluoroimmunoassay method using lanthanide chelate as labels.The procedure is simple because labeling process...A fluoroimmunoassay method using unlabeled europium chelate is described.The principle is similar to that of fluoroimmunoassay method using lanthanide chelate as labels.The procedure is simple because labeling process is omitted.The detection limit is about 10^(10) mol/L antigen.The relative standard deviation of immunoassay is less than 10%.The recoveries of human serum albumin and estradiol protein conjugate are 96-105% and 111% respectively.展开更多
[ Objective] The study aims at developing a novel fluorescence enhancement method to determine anionic surfactants. [ Method] Based on Fe3O4 @ PAA-RB fluorescent nanoparticles as fluorescent probes, we have developed ...[ Objective] The study aims at developing a novel fluorescence enhancement method to determine anionic surfactants. [ Method] Based on Fe3O4 @ PAA-RB fluorescent nanoparticles as fluorescent probes, we have developed a novel fluorescence enhancement method for the determi- nation of an anionic surfactant sodium dodecyl sulfate （SDS） through the gradual optimization of experiment conditions. [ Result] Under the opti- mum conditions, the extent of fluorescence enhancement is directly proportional to SDS concentration varying from 0.5 to 16.0 μmol/L, and the de- tection limit reaches 0.051 μmol/L. The relative standard deviation （RSD） for 4.0 μmol/L SDS is 3.3% （ n =6）. The proposed method has been successfully applied to the determination of SDS in environmental water samples, with recovery of 96.3% -105.5%. E Conclusion] The novel fluo- rescence enhancement method is not only simple and rapid, but also has avoided using tedious solvent-extraction and toxic organic solvents.展开更多
A fluoroimmunoassay method using unlabeled Terbium chelate is described.The principle is similar to that of fluoroimmunoassay method using lanthanide chelate as labels.The procedure is simpte because labeling process ...A fluoroimmunoassay method using unlabeled Terbium chelate is described.The principle is similar to that of fluoroimmunoassay method using lanthanide chelate as labels.The procedure is simpte because labeling process is unnecessary.The recovery of HSA and albumin in urine is 107% and 95% respectively.The standard deviation is tess than 10%.展开更多
The fluorescence quenching of inclusion complex of neutral red(NR)and hydroxypropyl-β-cyclodextrin(HP-β-CD)carried by chlorobenzene was investigated.The fluorescence intensity of NR increased due to the formed inclu...The fluorescence quenching of inclusion complex of neutral red(NR)and hydroxypropyl-β-cyclodextrin(HP-β-CD)carried by chlorobenzene was investigated.The fluorescence intensity of NR increased due to the formed inclusion complex of HP-β-CD and NR.But the fluorescence intensity of NR-HP-β-CD diminished when chlorobenzene was added,and there was a linear relationship between the fluorescence quenching value of the system(△IF=IF,NR-HP-β-CD-IF,CB-NB-NR-HP-β-CD)and the concentration of chlorobenzene.Based on this,a novel fluorescence quenching method for the determination of chlorobenzene with NR as a fluorescence probe has been developed.Under the optimal conditions,the linear range of calibration curve for the determination of chlorobenzene was 5.0×10^-8-8.0×10^-6 mol/L and the detection limit was 1.0×10^-8 mol/L.It has been applied to determination ofchlorobenzene in synthetic waste water samples with satisfactory results.展开更多
Add the masking agent and biscyclohexanoneoxalyldihydraone into the diluted clarificd liquid of the landfill leachate which was treatmented by digestion and centrifugal filtration to complexate all heavy metal ion in ...Add the masking agent and biscyclohexanoneoxalyldihydraone into the diluted clarificd liquid of the landfill leachate which was treatmented by digestion and centrifugal filtration to complexate all heavy metal ion in the trcatmented liquid, and extracted using CHCl3 many time, then it were demasking and decomposing respectively, and adjusted different pH and formed Me^n＋-PAN coordination compound when these metal ion reaction with PAN. The Fluoresence quenching of Rh6G （λex/λem=543mn/558nm） when the metal ion coordination compound was add into the Rh6G solution step by step, the quenching intensity was directly proportional to the concentration of the metal ion in the certain range. So a new method of fast and simple for determination of trace metal ion in landfill lcachate was established to determine metal ion in sample of different landfill leachate in Three Gorge Water Reservoir, and comparison the classic assay method with satisfactory results.展开更多
As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency...As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency of exciton utilization and the overall performance of organic light-emit-ting devices are closely linked to the singlet-triplet energy gap(ΔE_(ST))of MR-TADF emitters.Identifying an economic and accu-rate theoretical approach to predictΔE_(ST)would be beneficial for high-throughput screening and facilitate the inverse design of MR-TADF molecules.In this study,we evaluated the S_(1)state energy(E(S_(1))),T_(1)state ener-gy(E(T_(1))),andΔE_(ST)using three different physical interpretations:adiabatic excitation ener-gy,vertical absorption energy,and vertical emission energy.We employed the time-depen-dent density functional theory(TDDFT)and delta self-consistent field(ΔSCF)methods to calculate E(S_(1)),E(T_(1)),andΔE_(ST)for 20 MR-TADF molecules reported in the literature.We compared these calculated values with experimental data obtained from fluorescence spec-troscopy at room-temperature(or 77 K)and phosphorescence spectroscopy conducted at 77 K.Our findings indicate that the vertical absorption energy at the S0 state minimum,deter-mined by theΔSCF method,accurately predicts the S_(1)state energy.Similarly,the vertical absorption energy at the S0 state minimum,calculated using the TDDFT method,effectively predicts the T_(1)state energy.TheΔE_(ST)derived from the difference between these two excita-tion energies exhibited the smallest mean absolute error of only 0.039 eV compared to the ex-perimental values.This combination represents the most accurate and cost-effective method reported to date for predicting theΔE_(ST)of MR-TADF molecules,and can be integrated into AI-driven inverse design workflows for new emitters.展开更多
The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectr...The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.展开更多
Bisphenol A （BPA） is a chemical with high production volume and wide applications in many industries. Although BPA is known as an endocrine disruptor, its toxic mechanisms have not been fully characterized. Due to i...Bisphenol A （BPA） is a chemical with high production volume and wide applications in many industries. Although BPA is known as an endocrine disruptor, its toxic mechanisms have not been fully characterized. Due to its structural similarity to thyroid hormones thyroxine （T4） and triiodothyronine （T3）, one possible mechanism of BPA toxicity is disruption of hormone transport by competitive binding with the transport proteins. In this study, the binding interactions of BPA, T4, and T3 with three thyroid hormone transport proteins, human serum albumin （HSA）, transthyretin （TTR）, and thyroxine-binding globulin （TBG） were investigated by fluorescence measurement. Using two site-specific fluorescence probes dansylamide and dansyl-L-proline, the binding constants of BPA with HSA at drug site I and site II were determined as 2.90 × 10^4 and 3.14 × 10^4 L/mol, respectively. By monitoring the intrinsic fluorescence of tryptophan, a binding constant of 4.70 ×10^3 L/mol was obtained. Similarly, by employing 8-anilino-l-naphthalenesulfonic acid as fluorescence probe, the binding affinity of BPA with TTR and TBG was measured to be 3.10 × 10^5 and 5.90× 10^5 L/mol, respectively. In general, BPA showed lower binding affinity with the proteins than T3 did, and even lower affinity than T4. Using these binding constants, the amount of BPA which would bind to the transport proteins in human plasma was estimated. These results suggest that the concentrations of BPA commonly found in human plasma are probably not high enough to interfere with T4 transport.展开更多
Compared with other transition metal Mxene derived quantum dots(MQD_(S)),Ta-based Mxene quantum dots have good functionality,but Ta-based Mxene quantum dots and their applications have not been studied so far.In this ...Compared with other transition metal Mxene derived quantum dots(MQD_(S)),Ta-based Mxene quantum dots have good functionality,but Ta-based Mxene quantum dots and their applications have not been studied so far.In this paper,we report for the first time the synthesis of high fluorescence quantum yield(QY) N-doped Ta_(4)C_(3) quantum dots(N-MQDs) using Ta_(4)C_(3) quantum dots in acid reflux damaged Ta_(4)C_(3) nanosheets as precursors and ethylenediamine as nitrogen source.The prepared N-MQDs have excellent blue photoluminescence(PL) properties,particle size is only 2.60 nm,QY is up to 23.4%,and good stability.In addition,it has been reported that N-MQDs can be used as fluorescent probe for detection of Fe;and remote force sensing analysis In liquid ion sensing,N-MQDS shows a unique selective quenching of Fe;with a detection limit as low as 2 μmol/L,and has great potential as a fast and super-sensitive fluorescent probe for the detection of heavy ion.More importantly,in solid mechanics sensing,the introduction of N-MQDs into self-healing hydrogels can be developed into a fluorescent hydrogel that can be used for accurate remote force measurement and applied in the field of mechanical sensing analysis.Therefore,Ta-based N-MQDs show excellent potential in the field of fluorescence sensing,which provides a door for multi-dimensional sensing of new materials in the future.展开更多
文摘H pylori is etiologically associated with gastritis, gas-tric and duodenal ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Eradicating H pylori may convert rapidly the outcome of related diseases with the use of more accurate diagnostic molecular tests. Indeed some of the tests cannot give the evidence of current infection; H pylori can be detected by noninvasive and invasive methods, the latter requiring an endoscopy. Eradication failure is a big problem in H pylori infection. Recently, clarithromycin resistance in H pylori strains is increasing and eradicati-on therapy of this bacterium is becoming more difficult. Molecular methods have frequently been applied besides phenotypic methods for susceptibility testing to detect clarithromycin resistance due to mutations in the 2143 and 2144 positions of 23S rRNA gene. Fluorescence in situ hybridization (FISH) method on paraffin embedded tissue is a rapid, accurate and cost-effective method for the detection of H pylori infection and to determine clarithromycin resistance within three hours according to the gold standards as a non-culture method. This method can also be applied to fresh biopsy samples and the isolated colonies from a culture of H pylori, detecting both the culturable bacillary forms and the coccoid forms of H pylori, besides the paraffin embedded tissue secti-ons. This technique is helpful for determining the bac-terial density and the results of treatment where clarith-romycin has been widely used in populations to increase the efficacy of the treatment and to clarify the treatment failure in vitro.
基金supported by the National Natural Science Foundation of China(Grant No.61372046)the Research Fund for the Doctoral Program of Higher Education of China(New Teachers)(Grant No.20116101120018)+6 种基金the China Postdoctoral Science Foundation Funded Project(Grant Nos.2011M501467 and 2012T50814)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2011JQ1006)the Fundamental Research Funds for the Central Universities(Grant No.GK201302007)Science and Technology Plan Program,in Shaanxi Province of China(Grant Nos.2012 KJXX-29 and 2013K12-20-12)the Science and Technology Plan Program in Xian of China(Grant No.CXY1348(2))the.GraduateInovation Project of Northwest University(Grant No.YZZ12093)the Seience and Technology Program of Educational Committee,of Shaanxi Province of China(Grant No.12JK0729).
文摘Recently,the simplified spherical harmonics equations(SP)model has at tracted much att entionin modeling the light propagation in small tissue ggeometriesat visible and near-infrared wave-leng ths.In this paper,we report an eficient numerical method for fluorescence moleeular tom-ography(FMT)that combines the advantage of SP model and adaptive hp finite elementmethod(hp-FEM).For purposes of comparison,hp-FEM and h-FEM are,respectively applied tothe reconstruction pro cess with diffusion approximation and SPs model.Simulation experiments on a 3D digital mouse atlas and physical experiments on a phantom are designed to evaluate thereconstruction methods in terms of the location and the reconstructed fluorescent yield.Theexperimental results demonstrate that hp-FEM with SPy model,yield more accurate results thanh-FEM with difusion approximation model does.The phantom experiments show the potentialand feasibility of the proposed approach in FMT applications.
基金financially supported by the National Natural Science Foundation of China(No.21375112)the Marine hightech industry development projects of Fujian Province(No.2015-19)
文摘Heteroatom doping is an efficient approach to regulate the fluorescence properties of carbon dots.Using aminophenylboronic acid as the raw material,a combustion method was developed for the synthesis of boron,nitrogen-doped carbon dots（B,N-carbon dots）.The B,N-carbon dots emitted green fluorescence and displayed high resistance to both photo bleaching and ionic strength.A facile fluorescence sensing approach for Cu^2＋ was fabricated via static fluorescence quenching.Under optimal conditions,a rapid detection of Cu^2＋ could be completed in 2 min with a linearity ranging from 1 μmol/L to 25 μmol/L and a detection limit of 0.3 μmol/L Furthermore,the proposed method showed potential applications for the detection of Cu^2＋ in natural water samples.
文摘A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented.
文摘Based on a previous research of cavitation effect under bi-frequency ultrasound irradiation, this paper studies bi-frequency irradiations with similar experimental settings. The additional irradiation sources with frequencies of 1.04MHz, 0.8MHz and 1.7MHz are individually combined with the main ultrasonic irradiation source with frequency of 28kHz to form bi-frequency ultrasonic irradiation. The intensity of 28kHz irradiation was fixed at 12.5W/cm^2, while the intensity of the ultrasound at the other three frequencies is varied from1 W/cm^2 to 18 W/cm^2. It turns out that under the influence of the bi-frequency irradiation, the fluorescence intensity is obviously greater than the sum of those at individual frequencies. So the frequency of the additional sonication strikingly influences the fluorescence enhancement effect. For example, the fluorescence enhancement effect of 1.04MHz is stronger than that of 1.7MHz, and the enhancement effect of 0.8MHz is further stronger than that of 1.04MHz. Under the sonic intensity of (7.9)W/cm^2, the fluorescence intensity of 1.04MHz is approximately twice that of 1.7MHz while the fluorescence intensity of 0.8MHz is approximately 1.5 times that of 1.04MHz.
文摘The state of Tb3+ is investigated in liposome. When the concentration of PC is below CMC (critical micell concentration), most of Tb3+ is associated with PC, the binding constant is about 3.35×103 L/mol. When the concentration of PC is beyond CMC, most of Tb3+ is dimerized, the dimerization constant is about 3.92×104L/mol. In PC?CH?H2O system, the binding constant of Tb3+?CH complex 2.93×104L/mol is obtained.
文摘Fura-2 was first used to monitor intracellular RE(3+). The characterizations of RE3+-Fura-2 interactions in solutions simulating intracellular ionic composition show that La3+ and Y3+ both form 1:1 RE(3+)-fura-2 complexes. The apparent dissociation constants are 1.61×10(-7)M,and 4.04×10(-7)M,respectively. The mouse myeloma(SP2/0) cells exposed to free RE(3+) or free RE(3+) and some small molecules in body were Studied by single cell canon measurement system.The results support the assumption that RE(3+) ions cannot enter the cytoplasm of living cells, and the small molecules used in our experiments couldn't improve the permeability of RE(3+)ions.
文摘New HPLC method was developed for determination of amlodipine and valsartan in their binary mixture as a part of routine control of combined formulations. The method was validated to meet official requirements including selectivity, stability, linearity, precision and accuracy. Chromatography was carried out using a LiChrospher RP-18 column, a mixture containing acetonitrile, phosphate buffer of pH 3.5 and methanol (45:45:10, v/v/v) and new fluorescence detection at 255 nm for excitation and 448 nm for emission. The effect of methanol content, pH of the buffer, flow rate, detection wavelengths and column temperature was estimated in robustness study, according to a plan defined by the Plackett-Burman design. For identification of significant effects, both graphical and statistical methods were used. Ro-bustness for dissolution test was checked estimating the effects of paddle speed, temperature and pH of dissolution medium. The method was proved to complying with all official guidelines. Therefore, it is suitable for determination of amlodipine and valsartan in their binary mixtures for different analytical and pharmaceutical purposes.
基金Funded by the National Natural Science Foundation of China(No.21676015)
文摘The amorphous I/Au composite nanofilms were prepared by low vacuum direct current sputtering(LVDCS)method.The optimized preparation technologies contain growth pressure,time,gaseous environment and annealing conditions.The maximum fluorescence emission(λemmax)of I/Au nanofilms was observed at wavelength of 375 nm,and the intensity of fluorescence emission peak of annealed I/Au films was smaller than that of unannealed one due to fewer amorphous Au nanoparticles,caused by annealing treatment.In the UV-Vis absorption spectra,the intensity of UV-Vis absorption peak of annealed I/Au nanofilms is larger than that of the unannealed one.This work also developed a new way to grow I/Au composite fluorescent thin films.
基金Project for Improving Basic Research Ability of Middle Aged and Young Teachers in Colleges and Universities of Guangxi in 2017(2017KY0284)Project of Guangxi Key Laboratory of Zhuang and Yao Ethnic Medicine(GXZYKF2019-7)+2 种基金Program of Key Laboratory for Extraction and Purification and Quality Analysis of TCM in 2017(J1700208)Project of Guangxi University of Chinese Medicine(YB14004)Collaborative Innovation Center of Zhuang and Yao Ethnic Medicine([2013]No.20).
文摘[Objectives]To establish a new method for indirect determination of bisoprolol fumarate based on fluorescence quenching technology.[Methods]In ammonia water and ammonium chloride buffer solution at pH=9.2,whenλexcitation=277 nm andλemission=596 nm,with the increase of CCu2+,the fluorescence signal intensity of bisoprolol fumarate weakened,and the difference between the fluorescence intensity of bisoprolol fumarate itself and the fluorescence intensity of the test solution after the quencher Cu2+was added(ΔF)and Cbisoprolol fumarate showed a good linear relationship.[Results]In the range of 15.39-76.93μg/mL,ΔF=146.7 Cbisoprolol fumarate+482.1,r=0.9988,and the detection limit is 0.1391μg/mL.[Conclusions]The fluorescence quenching method has been applied to the determination of actual samples with a recovery rate of 99.9%and an RSD of 2.7%.The results are satisfactory.
基金supported by National Nature Science Foundation of China(No.11175244)
文摘In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming process;therefore,this work introduces an automatic focusing method for Soller slits in multi-element fluorescence detectors.This method establishes a relation model between the fluorescence intensity distribution and the coordinates of the fluorescence excitation point.According to this relation model,the actual coordinates of the fluorescence excitation point can be deduced from the detected fluorescence intensity distribution and used in focusing operations.This method has proven to be feasible in an XAFS experiment at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility.
基金This work was supported by National Natural Science Foundation of China.
文摘A fluoroimmunoassay method using unlabeled europium chelate is described.The principle is similar to that of fluoroimmunoassay method using lanthanide chelate as labels.The procedure is simple because labeling process is omitted.The detection limit is about 10^(10) mol/L antigen.The relative standard deviation of immunoassay is less than 10%.The recoveries of human serum albumin and estradiol protein conjugate are 96-105% and 111% respectively.
基金Supported by the Project of Chongqing Municipal Education Commis-sion(KJ101101)Project of Innovation Team for"Water Quality Vari-ation and Water Environmental Security of Three Gorge Reservoir"of Higher Education in Chongqing City(201024)
文摘[ Objective] The study aims at developing a novel fluorescence enhancement method to determine anionic surfactants. [ Method] Based on Fe3O4 @ PAA-RB fluorescent nanoparticles as fluorescent probes, we have developed a novel fluorescence enhancement method for the determi- nation of an anionic surfactant sodium dodecyl sulfate （SDS） through the gradual optimization of experiment conditions. [ Result] Under the opti- mum conditions, the extent of fluorescence enhancement is directly proportional to SDS concentration varying from 0.5 to 16.0 μmol/L, and the de- tection limit reaches 0.051 μmol/L. The relative standard deviation （RSD） for 4.0 μmol/L SDS is 3.3% （ n =6）. The proposed method has been successfully applied to the determination of SDS in environmental water samples, with recovery of 96.3% -105.5%. E Conclusion] The novel fluo- rescence enhancement method is not only simple and rapid, but also has avoided using tedious solvent-extraction and toxic organic solvents.
基金supported by National Commission of Natural Science Foundation of China.
文摘A fluoroimmunoassay method using unlabeled Terbium chelate is described.The principle is similar to that of fluoroimmunoassay method using lanthanide chelate as labels.The procedure is simpte because labeling process is unnecessary.The recovery of HSA and albumin in urine is 107% and 95% respectively.The standard deviation is tess than 10%.
基金This project was supported by the National Basic Research Program of China(No.2007CB936602)the Natural Science Foundation of Shandong Province in China(No.Y2008B20).
文摘The fluorescence quenching of inclusion complex of neutral red(NR)and hydroxypropyl-β-cyclodextrin(HP-β-CD)carried by chlorobenzene was investigated.The fluorescence intensity of NR increased due to the formed inclusion complex of HP-β-CD and NR.But the fluorescence intensity of NR-HP-β-CD diminished when chlorobenzene was added,and there was a linear relationship between the fluorescence quenching value of the system(△IF=IF,NR-HP-β-CD-IF,CB-NB-NR-HP-β-CD)and the concentration of chlorobenzene.Based on this,a novel fluorescence quenching method for the determination of chlorobenzene with NR as a fluorescence probe has been developed.Under the optimal conditions,the linear range of calibration curve for the determination of chlorobenzene was 5.0×10^-8-8.0×10^-6 mol/L and the detection limit was 1.0×10^-8 mol/L.It has been applied to determination ofchlorobenzene in synthetic waste water samples with satisfactory results.
文摘Add the masking agent and biscyclohexanoneoxalyldihydraone into the diluted clarificd liquid of the landfill leachate which was treatmented by digestion and centrifugal filtration to complexate all heavy metal ion in the trcatmented liquid, and extracted using CHCl3 many time, then it were demasking and decomposing respectively, and adjusted different pH and formed Me^n＋-PAN coordination compound when these metal ion reaction with PAN. The Fluoresence quenching of Rh6G （λex/λem=543mn/558nm） when the metal ion coordination compound was add into the Rh6G solution step by step, the quenching intensity was directly proportional to the concentration of the metal ion in the certain range. So a new method of fast and simple for determination of trace metal ion in landfill lcachate was established to determine metal ion in sample of different landfill leachate in Three Gorge Water Reservoir, and comparison the classic assay method with satisfactory results.
基金support provided by the National Natural Science Foundation of China(No.22273043).
文摘As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency of exciton utilization and the overall performance of organic light-emit-ting devices are closely linked to the singlet-triplet energy gap(ΔE_(ST))of MR-TADF emitters.Identifying an economic and accu-rate theoretical approach to predictΔE_(ST)would be beneficial for high-throughput screening and facilitate the inverse design of MR-TADF molecules.In this study,we evaluated the S_(1)state energy(E(S_(1))),T_(1)state ener-gy(E(T_(1))),andΔE_(ST)using three different physical interpretations:adiabatic excitation ener-gy,vertical absorption energy,and vertical emission energy.We employed the time-depen-dent density functional theory(TDDFT)and delta self-consistent field(ΔSCF)methods to calculate E(S_(1)),E(T_(1)),andΔE_(ST)for 20 MR-TADF molecules reported in the literature.We compared these calculated values with experimental data obtained from fluorescence spec-troscopy at room-temperature(or 77 K)and phosphorescence spectroscopy conducted at 77 K.Our findings indicate that the vertical absorption energy at the S0 state minimum,deter-mined by theΔSCF method,accurately predicts the S_(1)state energy.Similarly,the vertical absorption energy at the S0 state minimum,calculated using the TDDFT method,effectively predicts the T_(1)state energy.TheΔE_(ST)derived from the difference between these two excita-tion energies exhibited the smallest mean absolute error of only 0.039 eV compared to the ex-perimental values.This combination represents the most accurate and cost-effective method reported to date for predicting theΔE_(ST)of MR-TADF molecules,and can be integrated into AI-driven inverse design workflows for new emitters.
基金supported by the National Key R&D Project of China(No.2017YFC0602100)the National Natural Science Foundation of China(No.41774147)Sichuan Science and Technology Support Program(No.2015GZ0272)
文摘The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.
基金supported by the National Natural Science Foundation of China(No. 20890112,20921063,20825519)
文摘Bisphenol A （BPA） is a chemical with high production volume and wide applications in many industries. Although BPA is known as an endocrine disruptor, its toxic mechanisms have not been fully characterized. Due to its structural similarity to thyroid hormones thyroxine （T4） and triiodothyronine （T3）, one possible mechanism of BPA toxicity is disruption of hormone transport by competitive binding with the transport proteins. In this study, the binding interactions of BPA, T4, and T3 with three thyroid hormone transport proteins, human serum albumin （HSA）, transthyretin （TTR）, and thyroxine-binding globulin （TBG） were investigated by fluorescence measurement. Using two site-specific fluorescence probes dansylamide and dansyl-L-proline, the binding constants of BPA with HSA at drug site I and site II were determined as 2.90 × 10^4 and 3.14 × 10^4 L/mol, respectively. By monitoring the intrinsic fluorescence of tryptophan, a binding constant of 4.70 ×10^3 L/mol was obtained. Similarly, by employing 8-anilino-l-naphthalenesulfonic acid as fluorescence probe, the binding affinity of BPA with TTR and TBG was measured to be 3.10 × 10^5 and 5.90× 10^5 L/mol, respectively. In general, BPA showed lower binding affinity with the proteins than T3 did, and even lower affinity than T4. Using these binding constants, the amount of BPA which would bind to the transport proteins in human plasma was estimated. These results suggest that the concentrations of BPA commonly found in human plasma are probably not high enough to interfere with T4 transport.
基金supported by the National Natural Science Foundation of China (No. 81972901)the Key R&D Plan of Chenzhou (No. ZDYF202008)+1 种基金the Discipline Leader Startup Fund of Huazhong University of Science and Technology Union Shenzhen Hospital (No. YN2021002)Science Foundation of China University of Petroleum,Beijing (Nos. 2462019QNXZ02, 2462019BJRC007)。
文摘Compared with other transition metal Mxene derived quantum dots(MQD_(S)),Ta-based Mxene quantum dots have good functionality,but Ta-based Mxene quantum dots and their applications have not been studied so far.In this paper,we report for the first time the synthesis of high fluorescence quantum yield(QY) N-doped Ta_(4)C_(3) quantum dots(N-MQDs) using Ta_(4)C_(3) quantum dots in acid reflux damaged Ta_(4)C_(3) nanosheets as precursors and ethylenediamine as nitrogen source.The prepared N-MQDs have excellent blue photoluminescence(PL) properties,particle size is only 2.60 nm,QY is up to 23.4%,and good stability.In addition,it has been reported that N-MQDs can be used as fluorescent probe for detection of Fe;and remote force sensing analysis In liquid ion sensing,N-MQDS shows a unique selective quenching of Fe;with a detection limit as low as 2 μmol/L,and has great potential as a fast and super-sensitive fluorescent probe for the detection of heavy ion.More importantly,in solid mechanics sensing,the introduction of N-MQDs into self-healing hydrogels can be developed into a fluorescent hydrogel that can be used for accurate remote force measurement and applied in the field of mechanical sensing analysis.Therefore,Ta-based N-MQDs show excellent potential in the field of fluorescence sensing,which provides a door for multi-dimensional sensing of new materials in the future.
