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On the distinct molecular architectures of dipping- and spray-LbL films containing lipid vesicles

Aoki, Pedro H. B.; Alessio, Priscila; Volpati, Diogo; Paulovich, Fernando Vieira; Riul Junior, Antonio; Oliveira Junior, Osvaldo Novais de; Constantino, Carlos J. L.
Fonte: Elsevier; Lausanne Publicador: Elsevier; Lausanne
Tipo: Artigo de Revista Científica
ENG
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The introduction of spraying procedures to fabricate layer-by-layer (LbL) films has brought new possibilities for the control of molecular architectures and for making the LbL technique compliant with industrial processes. In this study we show that significantly distinct architectures are produced for dipping and spray-LbL films of the same components, which included DODAB/DPPG vesicles. The films differed notably in their thickness and stratified nature. The electrical response of the two types of films to aqueous solutions containing erythrosin was also different. With multidimensional projections we showed that the impedance for the DODAB/DPPG spray-LbL film is more sensitive to changes in concentration, being therefore more promising as sensing units. Furthermore, with surface-enhanced Raman scattering (SERS) we could ascribe the high sensitivity of the LbL films to adsorption of erythrosin.; FAPESP; CNPq; nBioNet network from CAPES (Brazil)

Comparison of the efficacy of Rose Bengal and erythrosin in photodynamic therapy against Enterobacteriaceae

Rossoni, Rodnei D.; Junqueira, Juliana Campos; Santos, Evelyn Luzia S.; Costa, Anna Carolina B.; Jorge, Antonio Olavo C.
Fonte: Springer London Ltd Publicador: Springer London Ltd
Tipo: Artigo de Revista Científica Formato: 581-586
ENG
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 07/54442-3; The aim of this study was to evaluate the effects of the photosensitizers Rose Bengal and erythrosin combined with a light-emitting diode (LED) on Enterobacteriaceae. Twelve Enterobacteriaceae strains isolated from the oral cavities of patients undergoing prolonged antibiotic therapy, including three Escherichia coli, three Enterobacter cloacae, three Klebsiella oxytoca and three Klebsiella pneumoniae, were studied. An Enterobacteriaceae suspension (10(6) cells/ml) was prepared from each clinical strain isolated from the human oral cavity and subjected to the following treatments: LED and Rose Bengal, LED and erythrosin, LED and physiological solution, and physiological solution only as control. A blue LED unit (460 nm), and Rose Bengal and erythrosin at a concentration of 50 A mu mol/l were used. After incubation at 37A degrees C for 48 h, the number of colony-forming units (CFU) was calculated and subjected to analysis of variance (ANOVA). The Enterobacterial strains were sensitive to photodynamic therapy with Rose Bengal. There was a reduction of approximately 7.14 log10 for Enterobacter cloacae, 7.73 log10 for Escherichia coli, 6.76 log10 for Klebsiella pneumoniae and 7.21 log10 for Klebsiella oxytoca. However...

A COMPARATIVE-STUDY OF 4 DIFFERENT STAINING METHODS FOR ESTIMATION OF LIVE YEAST FORM CELLS OF PARACOCCIDIOIDES-BRASILIENSIS

Sano, A.; Kurita, N.; Iabuki, K.; Coelho, R.; Takeo, K.; Nishimura, K.; Miyaji, M.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica Formato: 157-161
ENG
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A comparative study of four different staining methods for estimation of live yeast form cells of Paracoccidioides brasiliensis was carried out. The staining methods used were fluorescent staining, vital dye exclusion tests with erythrosin B and by Janus green and lactophenol cotton blue staining. Colony forming units (cfu) of the yeast form of eight P. brasiliensis isolates on brain heart infusion agar (BHIA) supplemented with 4% horse serum plus 5% P. brasiliensis cell extract (BHIA + HS + EXT) were examined for reliability of staining in determining the number of live fungal units in eight different isolates. Cfu on BHIA + HS + EXT plates showed an excellent plating efficiency over 96% in all isolates tested. The percentage of the live cells indicated by fluorescent staining (FL) or vital dye exclusion test with erythrosin B (EB) or Janus green (JG-1) was lower than that of cfu. By contrast, the percentage due to modified dye exclusion test with Janus green (JG-2) and that due to lactophenol cotton blue staining (LPCB) showed a close correration to that of cfu. Our results indicate that the modified dye exclusion test with Janus green and lactophenol cotton blue staining are useful for estimating cell viability of yeast form cells of P. brasiliensis.

Biodegradation of erythrosin B dye by paramorphic Neurospora crassa 74A

Jesus,Gisele Jane de; Corso,Carlos Renato; Campos,Adriana de; Franchetti,Sandra Mara Martins
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2010 EN
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The present work used paramorphic forms of Neurospora crassa 74A to remove erythrosine. The fungus culture was grown in medium containing the dye, as only carbon source for 2 and 90 h of interaction. A washing process using distilled water isolated the cellular mass mycelia was dried for 12 h at 105ºC and transformed in fine powder and analyzed in FTIR. The supernatant was analyzed through spectrophotometer UV-Vis and FTIR. Significant differences in the spectrum of UV-VIS and FTIR were observed between the control and the supernatant and between wall control and the walls colored by red, in FTIR for 2 and 90 h. Some significant bands were modified, suggesting the possibility of enzymatic biodegradation in proportion to the time of contact between the dye and fungal biomass.

Characterization of the Red Beet Plasma Membrane H+-ATPase Reconstituted in a Planar Bilayer System.

Briskin, D. P.; Basu, S.; Assmann, S. M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1995 EN
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The transport activity of the red beet (Beta vulgaris L.) plasma membrane H+-ATPase was examined following reconstitution into a planar bilayer membrane. Fusion of partially purified plasma membrane H+-ATPase with the bilayer membrane was accomplished by perfusion of proteoliposomes against the bilayer under hypoosmotic conditions. Following incorporation into the bilayer, an ATP-dependent current was measured that demonstrated properties consistent with those of the plasma membrane H+-ATPase. Current production was substrate specific for ATP, inhibited by orthovanadate, and insensitive to 200 nM erythrosin B but inhibited by 100 [mu]M erythrosin B. When current production was measured as a function of Mg:ATP concentration, a simple Michaelis-Menten relationship was observed and a Km of 0.62 mM was estimated. Current-voltage analysis of ATP-dependent current in the presence of 0.5 mM ATP, 20 mM ADP, 40 mM orthophosphate, and an opposing 2.5-unit [delta]pH revealed a reversal potential of about -149 mV. Based on the free energy available from ATP hydrolysis, this reversal potential is consistent with an H+/ATP stoichiometry of 1. This study demonstrates the usefulness of a planar bilayer system for investigation of energy coupling to H+ transport by the plasma membrane H+-ATPase.

Investigation of the Calcium-Transporting ATPases at the Endoplasmic Reticulum and Plasma Membrane of Red Beet (Beta vulgaris).

Thomson, L. J.; Xing, T.; Hall, J. L.; Williams, L. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1993 EN
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Calcium-transporting ATPases were compared in endoplasmic reticulum (ER)- and plasma membrane-enriched fractions of red beet (Beta vulgaris L.) storage tissue by measuring 45Ca uptake and calcium-dependent phosphoenzyme formation. The plasma membrane fraction was prepared by aqueous two-phase partitioning of a microsomal fraction and collecting the upper phase. The ER-enriched fraction was obtained by submitting a sucrose-gradient ER-enriched fraction to aqueous two-phase partitioning and collecting the lower phase; this reduced contaminating plasma membrane, which partitioned into the upper phase. The ATP-dependent calcium uptake observed in both fractions was released by the calcium ionophore A23187. Calcium uptake showed saturation kinetics for calcium with Km values of 0.92 mmol m-3 for the ER fraction and 1.24 mmol m-3 for the plasma membrane fraction. Uptake into both fractions was inhibited by vanadate and erythrosin B, although the plasma membrane system was slightly more sensitive to both inhibitors. Cyclopiazonic acid and thapsigargin, at low concentrations, had no marked effect on uptake. The plasma membrane system was less substrate-specific for ATP than the ER system, since it was able to use GTP and ITP to drive calcium transport at up to 50% of the level obtained with ATP. Following phosphorylation with [[gamma]-32P]ATP...

The Ca2+-Transport ATPase of Plant Plasma Membrane Catalyzes a nH+/Ca2+ Exchange 1

Rasi-Caldogno, Franca; Pugliarello, Maria C.; De Michelis, Maria I.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1987 EN
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Microsomal vesicles from 24-hour-old radish (Raphanus sativus L.) seedlings accumulate Ca2+ upon addition of MgATP. MgATP-dependent Ca2+ uptake co-migrates with the plasma membrane H+-ATPase on a sucrose gradient. Ca2+ uptake is insensitive to oligomycin, inhibited by vanadate (IC50 40 micromolar) and erythrosin B (IC50 0.2 micromolar) and displays a pH optimum between pH 6.6 and 6.9. MgATP-dependent Ca2+ uptake is insensitive to protonophores. These results indicate that Ca2+ transport in these microsomal vesicles is catalyzed by a Mg2+-dependent ATPase localized on the plasma membrane. Ca2+ strongly reduces ΔpH generation by the plasma membrane H+-ATPase and increases MgATP-dependent membrane potential difference (Δψ) generation. These effects of Ca2+ on ΔpH and Δψ generation are drastically reduced by micromolar erythrosin B, indicating that they are primarily a consequence of Ca2+ uptake into plasma membrane vesicles. The Ca2+-induced increase of Δψ is collapsed by permeant anions, which do not affect Ca2+-induced decrease of ΔpH generation by the plasma membrane H+-ATPase. The rate of decay of MgATP-dependent ΔpH, upon inhibition of the plasma membrane H+-ATPase, is accelerated by MgATP-dependent Ca2+ uptake, indicating that the decrease of ΔpH generation induced by Ca2+ reflects the efflux of H+ coupled to Ca2+ uptake into plasma membrane vesicles. It is therefore proposed that Ca2+ transport at the plasma membrane is mediated by a Mg2+-dependent ATPase which catalyzes a nH+/Ca2+ exchange.

Phosphorescence of protein-bound eosin and erythrosin. A possible probe for measurements of slow rotational mobility.

Garland, P B; Moore, C H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/12/1979 EN
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We used a pulsed dye laser working at 540 nm to excite triplet-state formation of eosin and erythrosin, either bound or unbound to bovine serum albumin, in aqueous solution anaerobically at pH 8 and 20-22 degrees C. Delayed emission from radiative transitions of the triplet state was readily detectable, both as delayed fluorescence and as red phosphorescence. Detection of the triplet state by measurement of phosphorescence at 645 nm upwards was at least 100-fold more sensitive than by absorbance measurements of ground-state depletion at 500 nm. When immobilized in poly(methyl methacrylate), the phosphorescence of eosin and erythrosin was polarized with an anisotropy parameter [Jablonski (1961) Z. Naturforsch. A16, 1-4] of about 0.25. The phosphorescence of erythrosin is sufficiently intense to be distinguishable from the long-wavelength end of fluorescence under conditions of continuous rather than pulsed excitation. Our observations suggest that phosphorescence depolarization of eosin or erythrosin probes could be used as a highly sensitive method of measuring rotational relaxation times in region from 10(-5) to 10(-3) s, such as those of the uniaxial rotation of membrane proteins.

Neurotransmitter release and nerve terminal morphology at the frog neuromuscular junction affected by the dye Erythrosin B

Augustine, George J.; Levitan, Herbert
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 EN
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1. The quantal release of neurotransmitter and the fine structure of frog neuromuscular junctions has been examined in the presence of the xanthene dye Erythrosin B.

Erythrosin B Phosphorescence Monitors Molecular Mobility and Dynamic Site Heterogeneity in Amorphous Sucrose

Pravinata, Linda C.; You, Yumin; Ludescher, Richard D.
Fonte: Biophysical Society Publicador: Biophysical Society
Tipo: Artigo de Revista Científica
EN
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Molecular mobility modulates the chemical and physical stability of amorphous biomaterials. This study used steady-state and time-resolved phosphorescence of erythrosin B to monitor mobility in thin films of amorphous solid sucrose as a function of temperature. The phosphorescence intensity (lifetime), emission energy, and red-edge excitation effect were all sensitive to localized molecular mobility on the microsecond timescale in the glass and to more global modes of mobility activated at the glass transition. Blue shifts in the emission spectrum with time after excitation and systematic variations in the phosphorescence lifetime with wavelength indicated that emission originates from multiple sites ranging from short lifetime species with red-shifted emission spectrum to long lifetime species with blue-shifted emission spectrum; the activation energy for nonradiative decay of the triplet state was considerably larger for the blue-emitting species in both the glass and the melt. This study illustrates that phosphorescence from erythrosin B is sensitive both to local dipolar relaxations in the glass as well as more global relaxations in the sucrose melt and provides evidence of the value of phosphorescence as a probe of dynamic site heterogeneity as well as overall molecular mobility in amorphous biomaterials.

Erythrosin B inhibits high affinity ouabain binding in guinea-pig heart Na+-K+-ATPase without influence on cardiac glycoside induced contractility.

Fricke, U.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1985 EN
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Binding of [3H]-ouabain to guinea-pig heart membranes enriched in Na+-K+-ATPase revealed two different cardiac glycoside binding sites. High affinity binding was obtained at a KD = 2.2 X 10(-7) mol 1(-1) (Bmax = 16.8 pmol ouabain mg-1 protein) whereas low affinity ouabain binding occurred at a KD much greater than 10(-6) mol 1(-1). To discover whether the two ouabain binding sites are functional in guinea-pig heart muscle, erythrosin B, an inhibitor of the high affinity ouabain binding in rat brain tissue, was tested in guinea-pig isolated heart muscle preparations. Erythrosin B proved to be a potent inhibitor of the Mg2+ (Na+)-dependent-, as well as Na+-K+-activated ATPase (ID50 = 9 X 10(-6) mol 1(-1). Contractility of guinea-pig isolated papillary muscles, however, was not influenced by erythrosin B in concentrations up to 1 X 10(-5) mol 1(-1). Only very high concentrations (4 X 10(-4) mol 1(-1) resulted in a slightly negative inotropic effect (about 20%). Erythrosin B dose-dependently inhibited [3H]-ouabain binding to the Na+-K+-ATPase (KD = - 3.6 X 10(-6) mol 1(-1). In a concentration of 1 X 10(-5) mol 1(-1) the dye abolish high affinity [3H]-ouabain binding without affecting the low affinity binding sites. In contrast, in guinea-pig isolated atria...

THE PHOTODYNAMIC ACTION OF EOSIN AND ERYTHROSIN UPON SNAKE VENOM

Noguchi, Hideyo
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 26/03/1906 EN
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Since the hæmolysins of the several venoms respond differently to photodynamic action, they may be regarded as possessing different chemical constitutions. As regards stability, cobra hæmolysin ranks first, daboia second, and Crotalus third. The toxicity of all the venoms is more or less diminished by eosin and erythrosin in sunlight. This reduction in toxicity depends upon chemical changes, of more or less profound nature, taking place in certain of the active principles of the venom. The more stabile the predominant active principles the less the reduction in toxicity, and vice versa. Venom-neurotoxins are highly resistant to photodynamic action, venom-hæmolysins are less resistant, while the hæmorrhagin and thrombokinase of Crotalus and daboia venoms exhibit weak powers of resistance to their action. Hence it follows that while cobra venom remained almost unaltered, rattlesnake and daboia venoms were greatly reduced in toxicity when mixed with the fluorescent dyes and exposed to sunlight. There is an interesting parallel between the action of eosin and erythrosin upon the different venoms and their reactions to other injurious agencies. For example, the hæmolysins of cobra and daboia venoms are more heat resistant than the hæmolysin of Crotalus venom...

Field and Laboratory Efficacy Studies of Erythrosin B for Musca domestica (Diptera: Muscidae) and Drosophila robusta (Diptera: Drosophilidae) Control

Burg, J. G.; Webb, J. D.; Knapp, F. W.; Cantor, A. H.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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A 1.0%liquid bait formulation of erythrosin B was tested for house fly, Musca domestica L., control in one room of an environmentally controlled caged-layer poultry facility. Reduced fly numbers were recorded between day 14 and day 17 in the room treated with erythrosin B, after 17 d populations increased significantly in treatment and control rooms. Increasing the light intensity to 188 or 386 lm/m2 for 8 h a day or increasing bait stations from one station per 87 m3 to one station per 70 m3 had no effect on developing house fly populations. Annoying levels of a vinegar fly, Drosophila robusta group, developed in the poultry facility during the study. Populations increased to >400 adults/m2 of wall surface by day 15, then declined in the treatment room to <1 adult/m2 by day 33. Mortality of house flies that had ingested a 1.0%liquid formulation of erythrosin B was recorded under laboratory light intensities of 51, 532, and 1,030 lm/m2. All three intensities resulted in mortality significantly higher than the control, but mortality among the light intensity treatments did not differ significantly. When house flies were supplied water with erythrosine B, mortality did not differ significantly from that of the control.

Evaluation of Dispersible Formulations of Erythrosin B for Field Control of Culex pipiens quinquefasciatus Say (Diptera: Culicidae)

Carpenter, Terry L.; Respicio, Napoleon C.; Heitz, James R.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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Eight dispersants were tested in combination with free-acid erythrosin B and fluorescein to determine their toxicity. Solidogen LT-13 and Aquonium C-IV were most effective in combination with erythrosin B. Aquonium C-IV, Emulphor EL-719, Nekal BX-78, and sodium dodecyl sulfate were equally effective in combination with fluorescein. None of the dispersants alone was toxic. Four formulations of erythrosin B (free-acid dispersed with 8% sodium dodecyl sulfate, microencapsulated free-acid, aluminum lake dispersed with 8% sodium dodecyl sulfate, and microencapsulated aluminum lake) were exposed to natural sunlight and environmental conditions for up to 28 days and tested for toxicity to fourth-instar Culex pipiens quinquefasciatus Say. The dispersed free-acid erythrosin B was most toxic of the four formulations tested. The dispersed free-acid was significantly toxic at 0.5 ppm, and all four formulations were toxic at 4.0 ppm. Dispersed and microencapsulated free-acid formulations exhibited residual toxicity up to 7 days. In small-plot field tests, the dispersed free-acid erythrosin B caused significant reductions in larval and adult populations of C. p. quinquefasciatus at concentrations ranging from 0.25 to 8.0 ppm.

The Joint Action of Coprecipitated Free-acid Formulations of Erythrosin B and Fluorescein Against the Larvae of Culex pipiens quinquefasciatus Say (Diptera: Culicidae)

Respicio, Napoleon C.; Carpenter, Terry L.; Heitz, James R.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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The joint toxicity of coprecipitated, free-acid, nondispersible and dispersible formulations of erythrosin B and fluorescein was studied on fourth-instar Culex pipiens quinquefasciatus Say. When used alone or in combination, the dispersible formulation was more toxic than its nondispersible counterparts. The dispersible 1:1 and 1:3 (erythrosin B: fluorescein) combinations were more toxic and faster acting than any of the components used alone. The nondispersible coprecipitated formulation failed to enhance toxicity. However, the dispersible combinations showed synergistic action, with the 1:1 combination exhibiting a greater degree of synergism than the 1:3 combination. The 24-h dark incubation treatment increased the toxic effects of the coprecipitated dispersible formulation and erythrosin B used alone, but suppressed the toxicity of fluorescein.

Joint Toxicity of Xanthene Dyes to the House Fly (Diptera: Muscidae)

Carpenter, Terry L.; Johnson, Lynne H.; Mundie, Thomas G.; Heitz, Andjames R.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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Eight xanthene dyes were tested to determine whether they would synergize the toxicity of erythrosin B to adult Musca domestica L. In 1:1 combinations, six dyes exhibited synergistic activity. These were rose bengal, eosin Y, diiodofluorescein, fluorescein, octabromofluorescein, and phloxin B. Dibromofluorescein was inactive, and dichlorofluorescein had an antagonistic effect. Increased efficiency of erythrosin B in killing insects by using lesser amounts in combination with certain other dyes was demonstrated.

Presynaptic effect of Erythrosin B at the frog neuromuscular junction: ion and photon sensitivity.

Augustine, G J; Levitan, H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 EN
Relevância na Pesquisa
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1. The anionic dye Erythrosin B increases quantal transmitter release from frog neuromuscular synapses. Experiments were performed to determine the role of ions and light in this presynaptic effect. 2. In calcium-free saline containing 1 mM-EGTA, Erythrosin B increased miniature end-plate potential (m.e.p.p.) frequency at a more rapid rate than in normal saline. 3. The dye's effect was influenced by extracellular calcium ions in a complex manner. Dye-induced release was minimal in Ringer solution containing 0.1 mM-calcium, and higher in calcium concentrations above or below 0.1 mM. 4. Erythrosin B-induced spontaneous release also occurred in saline which contained 1 mM-EDTA and was free of both calcium and magnesium ions. 5. Temporary removal of external sodium ions did not alter the progressive increase in m.e.p.p. frequency produced by the dye. 6. Elevation of the potassium concentration of the external medium (from 2 to 20 mM), which presumably depolarized nerve terminals and increased their calcium permeability, did not change the rate of increase of dye-induced release when preparations were in a reversed (outward) electrochemical gradient for calcium ions. 7. A reduction in light intensity of at least six orders of magnitude reduced the effect of Erythrosin B by 50%...

Kinetic Spectroscopy of Erythrosin Phosphorescence and Delayed Fluorescence in Aqueous Solution at Room Temperature

Duchowicz, Ricardo; Ferrer, M. Luisa; Acuña, A. Ulises
Fonte: American Society for Photobiology Publicador: American Society for Photobiology
Tipo: Artículo Formato: 6080 bytes; image/gif
ENG
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The photophysics and polarization of the phosphorescence and delayed fluorescence of erythrosin in conditions compatible with the current biological applications of the dye (aqueous buffers at pH 7.4 at ambient temperatures) and in ethanol have been studied as a function of dye concentration (10 −7-10−5M) and temperature (245–333K). The emission decay is strictly single exponential and the detailed kinetic analysis of all the rate processes connected with the emitting T1 state showed that (1) the lowering of the emission lifetime at the higher temperatures is due to a very efficient self-quenching process, (2) the back intersystem crossing rate Tx S1 is temperature dependent (δETS7 kcal mol−1) but the T1S0 is not (Ea0.1 kcal mol−1) and (3) both intersystem crossing processes are very sensitive to solvent polarity, which accounts for the solvent dependence of the phosphorescence yield and lifetime. The high value of the phosphorescence anisotropy (r0= 0.25 lt 0.006) is independent of the excitation and emission wavelengths, and its evolution in time accurately reflects the rotational restrictions in solid solutions. The relevance of these findings to studies with protein-dye conjugates is also outlined to facilitate the design and interpretation of phosphorescence depolarization experiments that probe the (μs-ms dynamics of biomolecules and supramolecular systems.; Peer reviewed

Spectral pH dependence of erythrosin B in sol-gel silica coatings and buffered solutions; Dependencia espectral de la eritrosina B con el pH en soluciones tampón y en recubrimientos sol-gel de silice

Montero, E. F.; García, M. A.; Villegas Broncano, María Ángeles; Llopis, J.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 656713 bytes; application/pdf
ENG
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[EN] Thin coatings optically sensitive against pH are obtained by entrapping erythrosin B molecules in a sol-gel silica matrix. Comparisons between optical spectra of erythrosin B in solutions and those once entrapped in silica coatings are performed for pH ranging from 0.5 to 12.0. Significant differences between both kinds of spectra (solutions and coatings) of erythrosin B are observed. Main changes are displayed in the absorption spectra for neutral to basic pH. Furthermore, the erythrosin B doped coatings show memory effect or hysteresis in their spectral response against pH. This means that absorption spectra depend on the direction of the pH change. Likewise, the photoluminescent spectra of erythrosin B in buffered solutions exhibit pH dependence and a maximized response in the basic pH range. On contrast, no significant photoluminescence from the erythrosin B entrapped in the silica coatings is observed. Results are mainly discussed on the basis of different optical response of polyprotic forms of erythrosin B and possible interactions between the molecule and oxygen as well as the porous walls of the sol-gel silica matrix. In addition, the presence of diffusional barriers, which hamper the flowing of protons and other associated ions...

Biofilm disclosing agents in complete denture: clinical and antimicrobial evaluation; Evidenciadores de biofilme em prótese total: avaliação clínica e antimicrobiana

Silva, Cláudia Helena Lovato da; Paranhos, Helena de Freitas Oliveira; Ito, Isabel Yoko
Fonte: Universidade de São Paulo. Faculdade de Odontologia Publicador: Universidade de São Paulo. Faculdade de Odontologia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 01/09/2002 POR
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This study evaluated the disclosing ability, removal facility and antimicrobial effect of biofilm disclosing agents applied on complete dentures. Disclosing ability was evaluated by means of the visual method. The solutions were applied on the internal surface of dentures. After being photographed, the dentures were brushed with denture-specific brush and dentifrice and photographed again. The obtained slides were projected on paper (10 X amplification) and the total and stained surfaces were outlined with graphite, cut off and weighed, in order to assess removal facility. The evaluation of antimicrobial effects was carried out by means of the method of diffusion in agar, and the results were obtained by measuring the length of the halos and rings. In terms of disclosing ability, the best solutions were 0.05% methylene blue, 5% erythrosin, 1% sodic fluorescein, Replak and 1% neutral red. One percent eosin, 1% sodic fluorescein and 5% erythrosin were the most easily removed solutions. One percent eosin, 5% erythrosin, 1% sodic fluorescein, 0.3% proflavine, Replak and 1% neutral red presented no antimicrobial effect. The solutions which presented the greatest disclosing ability and removal facility as well as absence of antimicrobial effect - which are essential requirements in the assessment of hygiene methods and guidance on oral health - were 1% eosin...