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Three esters of rhodamine B (1-3) differing in their alkyl chain lengths as well as several rhodamine B amides (4-9) were synthesized in good yields and tested for their cytotoxicity in SRB assays employing several human tumor cel...
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Three esters of rhodamine B (1-3) differing in their alkyl chain lengths as well as several rhodamine B amides (4-9) were synthesized in good yields and tested for their cytotoxicity in SRB assays employing several human tumor cell lines. The rhodamine B esters were unselective but showed cytotoxicity of as low as EC50 = 0.15 +/- 0.02 mu M. The rhodamine B amides were slightly less cytotoxic but showed good selectivity against MCF-7 and A2780 tumor cell lines. Especially a morpholinyl derivative4was similar to 20 time more cytotoxic for MCF-7 than for nonmalignant NIH 3T3 cells.
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Color developments based on the ion-association complexes of molybdothoric acid with three basic dyes (BD), rhodamine B(RB), butylrhodamine B(BRB) and nile blue (NB), were investigated in aqueous acidic solution in the presence of...
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Color developments based on the ion-association complexes of molybdothoric acid with three basic dyes (BD), rhodamine B(RB), butylrhodamine B(BRB) and nile blue (NB), were investigated in aqueous acidic solution in the presence of poly(vinyl alcohol) (PVA). Their spectrophotometric behavior, such as the conditions suitable for the reactions and the effects of foreign ions, were thoroughly studied. The Th:Mo:BD ratio in the complexes was found to be 1:12:3. Their absorption maxima were at 570, 570 and 590 nm with apparent molar absorptivities of 3.50 x 10 -6, 3.63 x 106 and 4.45 x 106 dm3 mol-1 cm -l, respectively. Beer's law was obeyed up to 0.8,0.8 and 0.7 ug thorium per 25 ml, respectively. The detection limits (3收起
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The development of nanostructures based on interaction of organic matrix and metal oxide particles (such as polypyrrole/zinc oxide composites) introduces interesting advantages due to synergistic/complementary photocatalytic activ...
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The development of nanostructures based on interaction of organic matrix and metal oxide particles (such as polypyrrole/zinc oxide composites) introduces interesting advantages due to synergistic/complementary photocatalytic activity of resulting material. Particularly, the available high surface area of resulting composite contributes with minimal aggregation of metal oxide nanoparticles and reduces the electron/hole pair recombination rate (if applied as a photocatalyst). Results indicate that superior performance is detected for composite of polypyrrole/zinc oxide applied in the photodegradation of rhodamine B and rhodamine 6G in comparison with degradation established by colloidal photocatalyst (surfactant/zinc oxide/dye). Progressive cleavage of organic dye molecule takes place in substitution to typical N-deethylation process.
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The adsorption behavior of Rhodamine B dye from aqueous solutions was investigated onto the cation-exchange resin, Duolite C-20 (hydrogen form). The effects of various experimental factors;sorbent amount, contact time, dye concent...
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The adsorption behavior of Rhodamine B dye from aqueous solutions was investigated onto the cation-exchange resin, Duolite C-20 (hydrogen form). The effects of various experimental factors;sorbent amount, contact time, dye concentration and temperature, were studied by using the batch technique. Lagergren pseudo-first-order equation shows good applicability with high correlation coefficients for all ranges of initial dye concentrations and at different temperatures. This equation was used to describe the kinetics of the dye adsorption process. The adsorption constants were evaluated by using both the Langmuir and Freundlich adsorption isotherm models. Thermodynamic parameters were obtained and it was found that the adsorption of Rhodamine B dye onto Duolite C-20 resin was an endothermic and spontaneous process at the temperatures under investigation.
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In this paper,the change of absorbance and their first and second derivatives for the Xanthene dyes as concentration dependence are reported.The effect of change of smoothing on the LOD and other analytical characteristics are inv...
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In this paper,the change of absorbance and their first and second derivatives for the Xanthene dyes as concentration dependence are reported.The effect of change of smoothing on the LOD and other analytical characteristics are investigated.Xanthene date from 1871 when Von Bayer synthesized fluorescein by the condensation of two moles of resorcinol with one mole of phthalic anhydride in the presence of concentrated sulfuric acid.
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Understanding of the TiO2-assisted phototransformations observed for fundamentally important derivatives of Rhodamine B is expected to bring consistent and eventually comprehensive knowledge on behavior of this dye. The photocatal...
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Understanding of the TiO2-assisted phototransformations observed for fundamentally important derivatives of Rhodamine B is expected to bring consistent and eventually comprehensive knowledge on behavior of this dye. The photocatalytic transformations of Rhodamine B in solution irradiated with visible light embrace an N-deethylation process eventually forming Rhodamine-110 rather than degradation of the chromophore. The N-deethylation of Rhodamine B was studied in solution and for the first time in the solid state. In this work, the influence of the wavelength of incident light on the photocatalytic processes involving Rhodamine dyes, is presented. The results indicate that the selection of wavelength is crucial to govern the pathway of RhB degradation. The N-deethylation process does not require reactive oxygen species, as assumed in literature, but the photoinduced electron transfer between the adsorbed RhB molecule and the TiO2 support, followed by radical transformations of the dye, plays a key role.
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Objectives The aim of the study was to investigate the effect of microneedle (MN) pretreatment on the transdermal delivery of a model drug (Rhodamine B, Rh B) encapsulated in polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) ...
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Objectives The aim of the study was to investigate the effect of microneedle (MN) pretreatment on the transdermal delivery of a model drug (Rhodamine B, Rh B) encapsulated in polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) focusing on the MN characteristics and application variables. Methods Gantrez MNs were fabricated using laser-engineered silicone micro-mould templates. PLGA NPs were prepared using a modified emulsion-diffusion-evaporation method and characterised in vitro. Permeation of encapsulated Rh B through MN-treated full thickness porcine skin was performed using Franz diffusion cells with appropriate controls. Key findings In-vitro skin permeation of the nanoencapsulated Rh B (6.19 ± 0.77 μg/cm 2/h) was significantly higher (P < 0.05) compared with the free solution (1.66 ± 0.53 μg/cm 2/h). Mechanistic insights were supportive of preferential and rapid deposition of NPs in the MN-created microconduits, resulting in accelerated dye permeation. Variables such as MN array configuration and application mode were shown to affect transdermal delivery of the nanoencapsulated dye. Conclusions This dual MN/NP-mediated approach offers potential for both the dermal and transdermal delivery of therapeutic agents with poor passive diffusion characteristics.
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A simple, sensitive spectrophotometric method in visible region has been developed for the determination of carvedilol (CAR) in bulk and in pharmaceutical formulations. The method is based on the reaction of CAR with measured exce...
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A simple, sensitive spectrophotometric method in visible region has been developed for the determination of carvedilol (CAR) in bulk and in pharmaceutical formulations. The method is based on the reaction of CAR with measured excess of eerie ammonium sulphate (CAS) followed by the determination of unreacted oxidant using Rhodamine B (RB). The reaction mixture exhibited maximum absorbance at 557 nm. The calibration graph is found to be linear over 14.0-28.0 μg ml~(-1) with molar absorptivity of 3.00 x 10~4 1 mol~(-1) cm~(-1) and the Sandell sensitivity of 0.0135 μg ml~(-1). The optimum reaction condition and other analytical parameters were evaluated. The method is successfully applied to the assay of CAR in tablet formulations.
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This paper describes the development of ZnO nanoparticles by a chemical method, to test them in the photocatalysis of the degradation of textile dyes, using Rhodamine B (RhB) as a probe reaction. The samples were submitted to diff...
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This paper describes the development of ZnO nanoparticles by a chemical method, to test them in the photocatalysis of the degradation of textile dyes, using Rhodamine B (RhB) as a probe reaction. The samples were submitted to different heat treatments in order to observe the annealing effects on the photocatalytical properties, surface decontamination and the consequent particle change, in terms of crystallinity. The as-prepared samples (ZOA) correspond to a metastable phase (oxy or hydroxy zinc acetate) and post annealing leads to ZnO crystallization. In spite of the XRD patterns showing only the ZnO phase for heat treatment at 100℃, FTIR data show that carboxylate groups remains attached to the ZnO surface up to 300℃. Up to 300℃ the presence of these carboxylate groups, provided by the synthesis method, showed to be more relevant to photoactivity than the specific surface area. At higher temperatures, crystallinity becomes the dominant factor and an increasing of crystallinity favors the photoactivity.
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The surface and interlayer structure of rhodamine B (RhB)-montmorillonite for various guest concentrations has been studied using a combination of X-ray powder diffraction and molecular modeling (molecular mechanics and molecular ...
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The surface and interlayer structure of rhodamine B (RhB)-montmorillonite for various guest concentrations has been studied using a combination of X-ray powder diffraction and molecular modeling (molecular mechanics and molecular dynamics) in the Cerius~2 modeling environment.The joint effect of surface and interlayer structure on the fluorescence spectrum has been observed and discussed in relation to the position and orientation of RhB~+cations with respect to the silicate layer.Structural analysis showed that the surface and interlayer structures are different as to the arrangement of RhB~+ cations,and both of them strongly depend on the guest concentration in the intercalation solution and on the method of preparation.The repeated intercalation of montmorillonite by rhodamine B used in the present work allowed obtaining RhB-montmorillonite in the maximum degree of ion exchange for every sample.
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