In conditions of monochromatic excitation (λexc=337.1), the spectral dependence of the efficiency of fluorescence quenching αλ of humic acids samples by Cd2+ and Cu2+ ions was studied. The difference of αλ depend...In conditions of monochromatic excitation (λexc=337.1), the spectral dependence of the efficiency of fluorescence quenching αλ of humic acids samples by Cd2+ and Cu2+ ions was studied. The difference of αλ dependencies for these ions was established. In the spectral range 350 - 650 nm, changes of the αλ for Cd2+ ion are markedly different from the magnitude for changes αλ, which occur for ion Cu2+. The interpretation of mismatch dependences obtained αλ ions Cd2+ and Cu2+ is carried out within the concept of the availability of different sites, due to the difference in ionic radii (0.108 nm and 0.08 nm for Cd2+ and Cu2+, respectively).展开更多
Optical absorption,excitation,and fluorescence were investigated in Eu ion-doped CdWO4 single crystal grown by a modified Bridgman method.The results indicate that Eu^2＋ and Eu^3＋ ions coexist in CdWO4 crystal and a...Optical absorption,excitation,and fluorescence were investigated in Eu ion-doped CdWO4 single crystal grown by a modified Bridgman method.The results indicate that Eu^2＋ and Eu^3＋ ions coexist in CdWO4 crystal and an energy transfer occurs between these Eu^2＋ and Eu^3＋ ions.When the crystal is excited by 266-nm light,the energy corresponding to the 4f65d to 8S7/2 transition of Eu^2＋ ions results in the excitation of the Eu^3＋ ions to the 5DJ level.The effect on fluorescence of annealing in oxygen at various temperatures was investigated.The excitation intensity of Eu^2＋ ions at 266 nm decreases as annealing temperature increases from 300 K to 1073 K,but it remains at a certain equilibrium level when the annealing temperature is further increased.展开更多
Sedum alfredii Hance has been identified as zinc(Zn) and cadmium(Cd) co-hyperaccumulator.In this paper the relationships of Zn or Cd hyperaccumulation to the generation and the role of H2O2 in Sedum alfredii H.were ex...Sedum alfredii Hance has been identified as zinc(Zn) and cadmium(Cd) co-hyperaccumulator.In this paper the relationships of Zn or Cd hyperaccumulation to the generation and the role of H2O2 in Sedum alfredii H.were examined.The results show that Zn and Cd contents in the shoots of Sedum alfredii H.treated with 1000 μmol/L Zn2+ and/or 200 μmol/L Cd2+ increased linearly within 15 d.Contents of total S,glutathione(GSH) and H2O2 in shoots also increased within 15 d,and then decreased.Total S and GSH contents in shoots were higher under Cd2+ treatment than under Zn2+ treatment.However,reverse trends of H2O2 content in shoots were obtained,in which much higher H2O2 content was observed in Zn2+-treated shoots than in Cd2+-treated shoots.Similarly,the microscopic imaging of H2O2 accumulation in leaves using H2O2 probe technique showed that much higher H2O2 accumulation was observed in the Zn2+-treated leaf than in the Cd2+-treated one.These results suggest that there are different responses in the generation of H2O2 upon exposure to Zn2+ and Cd2+ for the hyperaccumulator Sedum alfredii H.And this is the first report that the generation of H2O2 may play an important role in Zn hyperaccumulation in the leaves.Our results also imply that GSH may play an important role in the detoxification of dissociated Zn/Cd and the generation of H2O2.展开更多
Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in t...Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in the presence and absence of chelating agents,can be used as the criterion to evaluate the mobilizing capability of chelating agent.The F values determined experimentally lead to a mobilizing capability order:DTPA>EDTA>EGTA>NTA>TR1EN>PEN>CYS>HIS>SAThe polyaminopolycarboxylate type chelators mobilize cadmium effectively.A linear relationship was found between 1gF and lg k'CdL (conditional stability constant of the cadmium chelate).展开更多
Membrane based optical chemical sensor (optode) for Cd(II) was developed by the immobilization of a dye 1-(2-Pyridylazo)-2-Napthol (PAN) in the Tri-(2-Ethylhexyl) Phosphate (TEHP) plasticized Cellulose Triacetate (CTA...Membrane based optical chemical sensor (optode) for Cd(II) was developed by the immobilization of a dye 1-(2-Pyridylazo)-2-Napthol (PAN) in the Tri-(2-Ethylhexyl) Phosphate (TEHP) plasticized Cellulose Triacetate (CTA) matrix. Various combinations of PAN immobilized in the cellulose triacetate CTA and Polystyrene (PS) matrices plasticized with Tri-(2-Ethylhexyl) Phosphate TEHP, 2-Nitrophenyl Octyl Ether (NPOE) and Dioctyl Phthalate (DOP) were studied to arrive a suitable composition and found that the optode does not require any extractant to produce a distinct colour change on complexation with Cd(II). On sorption of Cd(II) in the optode matrix, PAN changes color of the optode from golden yellow to violet red having a maximum absorbance (lmax = 553 nm) within 150 min of total equilibration time at pH = 7.5. The optode developed in the present work was studied for its analytical application for Cd(II) in the aqueous samples by spectrophotometry and as well as Flame Atomic Absorption Spectrophotometry (FAAS). This preconcentrated optode showed a linear response by UV-visible spectrophotometry at λmax = 553 nm over a concentration range of 10 ng/mL–1 to 500 ng/mL–1 of Cd(II) ions. Where as the aqueous solutions was also subjected to FAAS before and after equilibration of the optode and found to be linear in the concentration range of 250 ng/mL–1 to 5000 ng/mL–1 of Cd(II) ions. The optode found to be reversible and can be desorbed by equilibrating it with 0.01 mol/L–1 HNO3. The applicability of the developed optode in real samples was studied by determining cadmium in the natural waters spiked with a known amount of Cd(II) ions.展开更多
We report the first time fabrication of a silver-α nano alumina thin film hybrid and the observation of the Surface Plasmon Coupled Emission (SPCE) phenomenon in these substrates. We report an “8” fold enhancement ...We report the first time fabrication of a silver-α nano alumina thin film hybrid and the observation of the Surface Plasmon Coupled Emission (SPCE) phenomenon in these substrates. We report an “8” fold enhancement in the intensity of the coupled emission signal with respect to the isotropic fluorescence signal. The coupled emission signal displayed a strong p-polarized (92%, p-polarized) output and directionality, which is in accordance with the theory of SPCE. The directionality of emission was found to have strong correlation with the theoretical modeling of minimum reflectivity calculations based on the theory of Surface Plasmon Resonance (SPR). We also report the novel extension of the fabricated substrates towards the economical and sensitive detection of toxic Cd2+ ions from aqueous solutions, which are of immense social relevance.展开更多
Interactions between Cd 2+ ions and salmon sperm DNA were investigated via UV Vis, Circular Dichroism(CD) and FT Raman spectroscopies. The experimental results show that Cd 2+ ions can coordinate with the phosphate gr...Interactions between Cd 2+ ions and salmon sperm DNA were investigated via UV Vis, Circular Dichroism(CD) and FT Raman spectroscopies. The experimental results show that Cd 2+ ions can coordinate with the phosphate groups of DNA and thus induce conformation changes of the DNA from B to A type.展开更多
文摘In conditions of monochromatic excitation (λexc=337.1), the spectral dependence of the efficiency of fluorescence quenching αλ of humic acids samples by Cd2+ and Cu2+ ions was studied. The difference of αλ dependencies for these ions was established. In the spectral range 350 - 650 nm, changes of the αλ for Cd2+ ion are markedly different from the magnitude for changes αλ, which occur for ion Cu2+. The interpretation of mismatch dependences obtained αλ ions Cd2+ and Cu2+ is carried out within the concept of the availability of different sites, due to the difference in ionic radii (0.108 nm and 0.08 nm for Cd2+ and Cu2+, respectively).
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50972061,51272109,and 21171102)the Natural Science Foundation of Zhejiang Province of China (Grant Nos. R4100364 and Z4110072)+1 种基金the Natural Science Foundation of Ningbo City (Grant No. 2012A610115)K. C.Wong Magna Fund in Ningbo University
文摘Optical absorption,excitation,and fluorescence were investigated in Eu ion-doped CdWO4 single crystal grown by a modified Bridgman method.The results indicate that Eu^2＋ and Eu^3＋ ions coexist in CdWO4 crystal and an energy transfer occurs between these Eu^2＋ and Eu^3＋ ions.When the crystal is excited by 266-nm light,the energy corresponding to the 4f65d to 8S7/2 transition of Eu^2＋ ions results in the excitation of the Eu^3＋ ions to the 5DJ level.The effect on fluorescence of annealing in oxygen at various temperatures was investigated.The excitation intensity of Eu^2＋ ions at 266 nm decreases as annealing temperature increases from 300 K to 1073 K,but it remains at a certain equilibrium level when the annealing temperature is further increased.
基金Project (Nos. 30630046 and 20777068) supported by the National Natural Science Foundation of China
文摘Sedum alfredii Hance has been identified as zinc(Zn) and cadmium(Cd) co-hyperaccumulator.In this paper the relationships of Zn or Cd hyperaccumulation to the generation and the role of H2O2 in Sedum alfredii H.were examined.The results show that Zn and Cd contents in the shoots of Sedum alfredii H.treated with 1000 μmol/L Zn2+ and/or 200 μmol/L Cd2+ increased linearly within 15 d.Contents of total S,glutathione(GSH) and H2O2 in shoots also increased within 15 d,and then decreased.Total S and GSH contents in shoots were higher under Cd2+ treatment than under Zn2+ treatment.However,reverse trends of H2O2 content in shoots were obtained,in which much higher H2O2 content was observed in Zn2+-treated shoots than in Cd2+-treated shoots.Similarly,the microscopic imaging of H2O2 accumulation in leaves using H2O2 probe technique showed that much higher H2O2 accumulation was observed in the Zn2+-treated leaf than in the Cd2+-treated one.These results suggest that there are different responses in the generation of H2O2 upon exposure to Zn2+ and Cd2+ for the hyperaccumulator Sedum alfredii H.And this is the first report that the generation of H2O2 may play an important role in Zn hyperaccumulation in the leaves.Our results also imply that GSH may play an important role in the detoxification of dissociated Zn/Cd and the generation of H2O2.
文摘Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in the presence and absence of chelating agents,can be used as the criterion to evaluate the mobilizing capability of chelating agent.The F values determined experimentally lead to a mobilizing capability order:DTPA>EDTA>EGTA>NTA>TR1EN>PEN>CYS>HIS>SAThe polyaminopolycarboxylate type chelators mobilize cadmium effectively.A linear relationship was found between 1gF and lg k'CdL (conditional stability constant of the cadmium chelate).
文摘Membrane based optical chemical sensor (optode) for Cd(II) was developed by the immobilization of a dye 1-(2-Pyridylazo)-2-Napthol (PAN) in the Tri-(2-Ethylhexyl) Phosphate (TEHP) plasticized Cellulose Triacetate (CTA) matrix. Various combinations of PAN immobilized in the cellulose triacetate CTA and Polystyrene (PS) matrices plasticized with Tri-(2-Ethylhexyl) Phosphate TEHP, 2-Nitrophenyl Octyl Ether (NPOE) and Dioctyl Phthalate (DOP) were studied to arrive a suitable composition and found that the optode does not require any extractant to produce a distinct colour change on complexation with Cd(II). On sorption of Cd(II) in the optode matrix, PAN changes color of the optode from golden yellow to violet red having a maximum absorbance (lmax = 553 nm) within 150 min of total equilibration time at pH = 7.5. The optode developed in the present work was studied for its analytical application for Cd(II) in the aqueous samples by spectrophotometry and as well as Flame Atomic Absorption Spectrophotometry (FAAS). This preconcentrated optode showed a linear response by UV-visible spectrophotometry at λmax = 553 nm over a concentration range of 10 ng/mL–1 to 500 ng/mL–1 of Cd(II) ions. Where as the aqueous solutions was also subjected to FAAS before and after equilibration of the optode and found to be linear in the concentration range of 250 ng/mL–1 to 5000 ng/mL–1 of Cd(II) ions. The optode found to be reversible and can be desorbed by equilibrating it with 0.01 mol/L–1 HNO3. The applicability of the developed optode in real samples was studied by determining cadmium in the natural waters spiked with a known amount of Cd(II) ions.
文摘We report the first time fabrication of a silver-α nano alumina thin film hybrid and the observation of the Surface Plasmon Coupled Emission (SPCE) phenomenon in these substrates. We report an “8” fold enhancement in the intensity of the coupled emission signal with respect to the isotropic fluorescence signal. The coupled emission signal displayed a strong p-polarized (92%, p-polarized) output and directionality, which is in accordance with the theory of SPCE. The directionality of emission was found to have strong correlation with the theoretical modeling of minimum reflectivity calculations based on the theory of Surface Plasmon Resonance (SPR). We also report the novel extension of the fabricated substrates towards the economical and sensitive detection of toxic Cd2+ ions from aqueous solutions, which are of immense social relevance.
文摘Interactions between Cd 2+ ions and salmon sperm DNA were investigated via UV Vis, Circular Dichroism(CD) and FT Raman spectroscopies. The experimental results show that Cd 2+ ions can coordinate with the phosphate groups of DNA and thus induce conformation changes of the DNA from B to A type.
