By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm ...By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm DNA and yeast RNA were determined at 12℃. The corresponding free energy change, enthalpy change and entropy change of the long range assembly were calculated at the same temperature. It was found the assembly complexes are very stable and the assembly is a spontaneous process characterized an entropy increase.展开更多
The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assem...The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assembles on the surface of positively-charged gold nanopar-ticle, which results in the [(Au)n(H2L)m]x? complex. In other words, one of carboxylate oxygens in (H2L)2? moves inward and combines with gold nanoparticle. The other carboxylate oxygens moves outward to form a supermolecular complex anion with x negative charges. Then by virtue of electrostatic attraction, hydrophobic force and charge transfer action, the complex anion binds with ST cation to form a new ion-association complex. Here (H2L)2? acts as a bridge. The forma-tion of the complex results in the significant enhancement of RRS intensity, the appearance of new RRS spectrum, the red shift of plasma absorption band of gold nanoparticle as well as the decrease in the absorbance and fluorescence quenching for safranine T. In this work, the inter-action between gold nanoparticle and ST on the RRS, absorption and fluorescence spectra has been investigated. The reason why RRS intensity increases greatly and the reaction mechanism have been inquired. The results show that RRS spectra can not only be used to study nanopar-ticle and reaction product, but also are a sensitive means to characterize and detect nanoparti-cles.展开更多
A study of the electrochemical reduction behavior of safranine T by means of electrochemical methods coupled with ESR （electron spin resonance） is presented. Through an "in situ" tracing of the 1-electron ...A study of the electrochemical reduction behavior of safranine T by means of electrochemical methods coupled with ESR （electron spin resonance） is presented. Through an "in situ" tracing of the 1-electron reduction intermediate—free radical, the structure of the free radical has been deduced. During the electrochemical reduction the free radical went through a post-electrolysis chemical decay including parallel steps of zero and first order reactions. This fact gives further support and experimental ascertainment of the viewpoint that some electrode processes are clearly related to the enzymatic catalyses<sup>[1]</sup>. In accordance with the chemical behavior of safranine T free radicals at various concentrations and at different potentials the authors have advanced a scheme of reaction mechanism and evaluated the kinetic parameters of the reation steps by simulating the experimental curves.展开更多
We report a comparative investigation of the characteristics of modified TiO2 nanorods grown on conducting indium tin oxide glass （/TO） substrates by two different hydrothermal methods： the direct method by which r...We report a comparative investigation of the characteristics of modified TiO2 nanorods grown on conducting indium tin oxide glass （/TO） substrates by two different hydrothermal methods： the direct method by which rutile TiOa nanorods were grown directly on plain ITO substrates and the seed-mediated one using which a thin film of anatase TiO2 seed layer was laid down by spin coating and annealing prior to the growth of TiO2 nanorods on it. Microstructural analysis of the samples using X-ray diffraction confirmed their rutile nature. The average crystallite size estimated using Scherrer＇s formula was found to fall in the range of 11-17 nm in both cases. Field emission scanning electron microscopy revealed the nanorod morphologies of a dandelion arrangement in the case of directly grown ones and a proper vertical orientation in the case of the seed-mediated method. UV-Vis spectroscopy analysis of both the samples exhibited redshifts with intense absorption of visible radiation, and the seed-mediated one was found to possess an increased bandgap. The transport nature of the samples was characterized by significant increase in both dark and photocurrents. The results show that the dark and photocurrent values of the directly grown TiO2 nanorods were greater than those of the seed-mediated ones by - seven and five folds, respectively, and therefore, it could serve as efficient photoelectrodes in dye-sensitized solar cells.展开更多
Crocus sativus L.,a member of the Iridaceae family,commonly known as saffron has very much popular as both medicine and spice.Earlier saffron was used as one of the important constituents in opioid preparations for pa...Crocus sativus L.,a member of the Iridaceae family,commonly known as saffron has very much popular as both medicine and spice.Earlier saffron was used as one of the important constituents in opioid preparations for pain relief.Its uses in the treatment of mild-to-moderate depression are well documented.Depression can affect the quality of life of individuals by causing headaches,difficulty in thinking,and loss of interest.Many clinical trials have been conducted for evaluating the efficacy of saffron in depression cases.Almost fifty constituents of C.sativus L are well known.Few of the major constituents include crocin,picrocrocin,and safranal.In the present review,the main focus is on the antidepressant effects of saffron and its major constituents,in which it was found that saffron has substantial effects on depression and anxiety because of double-blind study the data can be trusted.展开更多
文摘By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm DNA and yeast RNA were determined at 12℃. The corresponding free energy change, enthalpy change and entropy change of the long range assembly were calculated at the same temperature. It was found the assembly complexes are very stable and the assembly is a spontaneous process characterized an entropy increase.
基金the National Natural Science Foundation of China(Grant No.20175018).
文摘The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assembles on the surface of positively-charged gold nanopar-ticle, which results in the [(Au)n(H2L)m]x? complex. In other words, one of carboxylate oxygens in (H2L)2? moves inward and combines with gold nanoparticle. The other carboxylate oxygens moves outward to form a supermolecular complex anion with x negative charges. Then by virtue of electrostatic attraction, hydrophobic force and charge transfer action, the complex anion binds with ST cation to form a new ion-association complex. Here (H2L)2? acts as a bridge. The forma-tion of the complex results in the significant enhancement of RRS intensity, the appearance of new RRS spectrum, the red shift of plasma absorption band of gold nanoparticle as well as the decrease in the absorbance and fluorescence quenching for safranine T. In this work, the inter-action between gold nanoparticle and ST on the RRS, absorption and fluorescence spectra has been investigated. The reason why RRS intensity increases greatly and the reaction mechanism have been inquired. The results show that RRS spectra can not only be used to study nanopar-ticle and reaction product, but also are a sensitive means to characterize and detect nanoparti-cles.
基金Project supported by the National Natural Science Foundation of China.
文摘A study of the electrochemical reduction behavior of safranine T by means of electrochemical methods coupled with ESR （electron spin resonance） is presented. Through an "in situ" tracing of the 1-electron reduction intermediate—free radical, the structure of the free radical has been deduced. During the electrochemical reduction the free radical went through a post-electrolysis chemical decay including parallel steps of zero and first order reactions. This fact gives further support and experimental ascertainment of the viewpoint that some electrode processes are clearly related to the enzymatic catalyses<sup>[1]</sup>. In accordance with the chemical behavior of safranine T free radicals at various concentrations and at different potentials the authors have advanced a scheme of reaction mechanism and evaluated the kinetic parameters of the reation steps by simulating the experimental curves.
基金partially funded by the Loyola College-Times of India Major Research Grants (6LCTOI14LIF002)
文摘We report a comparative investigation of the characteristics of modified TiO2 nanorods grown on conducting indium tin oxide glass （/TO） substrates by two different hydrothermal methods： the direct method by which rutile TiOa nanorods were grown directly on plain ITO substrates and the seed-mediated one using which a thin film of anatase TiO2 seed layer was laid down by spin coating and annealing prior to the growth of TiO2 nanorods on it. Microstructural analysis of the samples using X-ray diffraction confirmed their rutile nature. The average crystallite size estimated using Scherrer＇s formula was found to fall in the range of 11-17 nm in both cases. Field emission scanning electron microscopy revealed the nanorod morphologies of a dandelion arrangement in the case of directly grown ones and a proper vertical orientation in the case of the seed-mediated method. UV-Vis spectroscopy analysis of both the samples exhibited redshifts with intense absorption of visible radiation, and the seed-mediated one was found to possess an increased bandgap. The transport nature of the samples was characterized by significant increase in both dark and photocurrents. The results show that the dark and photocurrent values of the directly grown TiO2 nanorods were greater than those of the seed-mediated ones by - seven and five folds, respectively, and therefore, it could serve as efficient photoelectrodes in dye-sensitized solar cells.
文摘Crocus sativus L.,a member of the Iridaceae family,commonly known as saffron has very much popular as both medicine and spice.Earlier saffron was used as one of the important constituents in opioid preparations for pain relief.Its uses in the treatment of mild-to-moderate depression are well documented.Depression can affect the quality of life of individuals by causing headaches,difficulty in thinking,and loss of interest.Many clinical trials have been conducted for evaluating the efficacy of saffron in depression cases.Almost fifty constituents of C.sativus L are well known.Few of the major constituents include crocin,picrocrocin,and safranal.In the present review,the main focus is on the antidepressant effects of saffron and its major constituents,in which it was found that saffron has substantial effects on depression and anxiety because of double-blind study the data can be trusted.
