Dilute Dye Solutions Research Articles

Laser action in condensed disordered media of active dye-stained animal tissues and sandy colloidal scattering walls

Significant narrowing of both the spectral and temporal profiles of emission radiation from optically pumped dyes was observed in discrete and continuously disordered media such as dilute colloidal dye solutions and densely packed forms of sandy powders and animal tissue treated with rhodamine 640 dye solution. The narrowing of the spectral and temporal response is attributed to laser action arising from feedback of the emission radiation from the surrounding scattering walls into the photoexcited dye regions of the animal and sandy colloidal disordered media.

Application of nonfoaming bubble separation to enrichment of dilute dye solution.

Application of nonfoaming bubble separation to enrichment of dilute dye solution.

動的走査吸液計の開発と応用 ブリストー測定の迅速化と改良をめざして

A new apparatus (dynamic scanning absorptometer ; DSA) has been developed for analyzing short-time liquid absorption behaviors of paper. It involves a computer-controlled turntable mechanism holding the paper specimen, onto which a liquid supply head is contacted. The rate of liquid absorption is measured by optically tracking the motion of meniscus in the glass capillary connected to the supply head. The results are analyzed and graphically displayed by computer in real time. Thus the apparatus provides a quick (5-15 min for an entire plot) and fully automated version of the Bristow absorption measurement, using a single sheet specimen of ca. 20 cm × 20 cm. The results of DSA measurement using distilled water and dilute dye solutions agreed well with each other and with those of the Bristow measurement, except for 10-20% greater values with the former in the long contact time regions for the hardsized paper. This discrepancy is considered to reflect overestimation of wetted area in the Bristow measurement, resulting from unevenness of liquid application caused by surface tension effect in the liquid supply head. The DSA is applicable also to nonaqueous or viscous liquids as test liquids.

Convective transport in diffusive samplers

Convective transport in diffusive samplers was determined by the loss of a dilute dye solution from these samplers while held in a water bath. The water flow in the bath was adjusted to give the same Reynolds number had the diffusive sampler been exposed to an airborne analyte at a predetermined flow velocity. By numerical analysis, estimates were made of the degree of interference of convection on sampler performance. The results indicate an enormous difference between commercial diffusive samplers with respect to the effect of convection on the transport of analyte into the sampler.

DNA SEQUENCING BY CAPILLARY GEL ELECTROPHORESIS AND LASER-INDUCED FLUORFSCIIVCE DETECTION

Detection limits of one to two thousand analyte molecules is produced by laser-induced fluorescence with the sheath flow cuvette for DNA sequencing. Two different detector systems are developed for the sequencing of real DNA samples: a single laser and single emission spectral channel system for the sequencing technique of Richardson and Tabor and a single laser excitation and dual emission spectral channel detector for the sequencing technique of DuPont. The best detection limits (1, 400 molecules) are obtained with a 750-μw helium-neon laser (λ=544nm), a cooled PMT, and tetramethylrhodamine labeled primer used with the Richardson/Tabor sequencing technique. Although better detection limits have been reported for the determination of highly dilute neat dye solution, these results for DNA sequencing are unprecedented for the analysis of real samples and are made possible by the extreme specificity of the Sanger chain-terminating reaction, the extreme resolution of capillary gel electrophoresis, and the extreme detection performance of laser induced fluorescence with the sheath flow cuvette.

Effect of β-cyclodextrin on the fluorescence, absorption and lasing of rhodamine 6G, rhodamine B and fluorescein disodium salt in aqueous solutions

The fluorescence, absorption and lasing of three xanthene dyes, rhodamine 6G, rhodamine B and the disodium salt of fluorescein were examined in aqueous solutions with and without added β-cyclodextrin. β-cyclodextrin enhances both fluorescence and lasing for all three dyes in concentrated (10 −3 M) aqueous dye solutions. In dilute (10 −5 to 10 −8 M) aqueous dye solutions, β-cyclodextrin can induce either enhancement or quenching of fluorescence and absorption depending on the nature and concentration of the dye. Deaggregation in concentrated solutions and variable complex formation in dilute solutions are proposed to account for the β-cyclodextrin-induced effects.

Critical-angle measurement of refractive index of absorbing materials: an experimental study

Critical-angle measurements of the refractive index of dilute dye solutions are presented. These provide experimental support for a recent theoretical assertion that optical absorption in a refractometric sample can give rise to large errors in critical-angle measurements of refractive index. The error in the transmission mode is shown to be much larger than the corresponding reflection mode error.

Direct measurement of dilute dye solution quantum yield by photothermal laser heterodyne interferometry

Laser heterodyne measurements have been used to study the nonradiative energy loss of isolated rhodamine 6G molecules in methanol solutions with different potassium iodide quencher concentrations. Simultaneous measurement of both the relative fluorescent intensity and photothermal phase modulation induced by argon ion laser excitation allows absolute determination of both the quantum yield and the fraction of absorbed photo-energy converted to heat. At zero quencher concentration, their values were found to be 98.2% and 12%, respectively.

Linear sweep voltammetry of adsorbed neutral red

The strong adsorption of neutral red on mercury causes its linear sweep voltammetry to be adsorption controlled over a wide range of conditions. At pH 4.5 or below, the surface coverage of DH+ increases monotonically from 1 monlayer in 3×10−7 M solution to ca. 3 monolayers in 3×10−4 M solution, and to a good approximation the monomeric, dimeric and tetrameric forms of the dye are adsorbed equally strongly. The morphology of the adsorption peak indicates that interactions between adsorbed molecules are substantial and that the nature of these interactions changes from moderately repulsive below pH 4 to strongly attractive above pH 6. Over this pH range the voltammograms of 2×10−4 M dye narrow progressively and ultimately split into two extremely sharp peaks. The first of these corresponds to the single voltammetric peak observed for dilute dye solutions, wheres the second represents the reduction of an electrochemically distinguishable phase of adsorbed dye. Above pH 9 the isotherm for adsorption of D exhibits an abrupt increase when the bulk concentration exceeds the equilibrium solubility.

Linear sweep voltammetry of adsorbed neutral red

The strong adsorption of neutral red on mercury causes its linear sweep voltammetry to be adsorption controlled over a wide range of conditions. At pH 4.5 or below, the surface coverage of DH + increases monotonically from 1 monlayer in 3×10 −7 M solution to ca. 3 monolayers in 3×10 −4 M solution, and to a good approximation the monomeric, dimeric and tetrameric forms of the dye are adsorbed equally strongly. The morphology of the adsorption peak indicates that interactions between adsorbed molecules are substantial and that the nature of these interactions changes from moderately repulsive below pH 4 to strongly attractive above pH 6. Over this pH range the voltammograms of 2×10 −4 M dye narrow progressively and ultimately split into two extremely sharp peaks. The first of these corresponds to the single voltammetric peak observed for dilute dye solutions, wheres the second represents the reduction of an electrochemically distinguishable phase of adsorbed dye. Above pH 9 the isotherm for adsorption of D exhibits an abrupt increase when the bulk concentration exceeds the equilibrium solubility.

Collaborative Study of the Pro-Milk Method for the Determination of Protein in Milk

Abstract Seven milk samples and 2 standard dye solutions were analyzed for protein content by the Pro-Milk method by 6 collaborating laboratories. Interlaboratory variations, although small, were significant, probably because of extremely good precision. Blind duplicates (2 sets) did not differ from each other. Tests of dilute dye solutions, involving only the colorimeters, showed interlaboratory variation, which indicates the need to carefully calibrate each instrument. The magnitudes of the variations encountered in the milk and dye solution studies were sufficiently small to allow adoption of the Pro-milk method as official first action.

A study by electron microscopy of the formation of new surface by Chaos chaos

The cell surface of the ameba Chaos chaos was “coated” with Alcian Blue by exposure of the cells to dilute dye solutions at 5 °C. At this temperature the amebae are immobilized. Formation of new surface was studied after rinsing the specimens and removing them to a fresh drop of medium at room temperature. Direct observations of amebae indicated that complete turnover of surface occurred in about 35 min but that the resultant new surface was probably not as convoluted as the original. Rate of formation of surface when amebae were recycled through the dye treatment was much slower. As previously reported, electron micrographs of fixed specimens showed that in dye-treated cells the surface filaments seen in untreated cells were replaced by dense clumps occurring at irregular intervals. New surface possessed all the layers of surface found in untreated cells. In sections including recently formed surface, the plasmalemma was smooth and few vesicles were seen in the underlying cytoplasm. In some sections clumps of old surface were found with surface filaments passing through them. More typically, a series of transitional profiles between typical filaments and typical clumps could be seen. Frequency counts of the clumps on photomicrographs before and after new surface formation provided no evidence for the hypothesis that there may be slippage between surface coat and underlying plasmalemma. In the cytoplasm of the uroid of amebae 15 min after return to room temperature, extensive areas of convoluted membranes bearing typical dense clumps were found. It is concluded that under the present conditions there is rapid and extensive formation of new surface which possesses all the morphological layers of the original surface. A mechanism involving interpolation of ground cytoplasm into the new surface appears to account better for the findings than one involving fusions of vesicles with the surface.

The vital staining of Amoeba proteus

ABSTRACT The effect of keeping Amoeba proteus in dilute basic dye solutions was studied. It was found that Nile blue, neutral red, and neutral violet in particular, and also brilliant cresyl blue, methylene blue, Bismarck brown, thionin, toluidine blue, and azures A and B act as vital dyes, while at comparable molarities crystal violet, dahlia, safranin, methyl green, Janus green, and Victoria blue are lethal, and do not produce any stain-ing until after death. Azure C, basic fuchsin, and particularly pyronine G are relatively harmless, but produce no vital staining. All the vital dyes stain the food vacuoles, and all produce small, darkly stained granules in colourless vacuoles in the cytoplasm. The latter do not exist in the unstained amoeba. Some of the dyes colour vacuoles around the crystals. These crystal vacuoles also seem to be induced. A few of the dyes colour the spherical refractive bodies, which are at least in part phospholipid. All the basic dyes used with the possible exception of azure C, methyl green, and pyronine G attach to the external membrane of A. proteus in an orientated manner, as shown by the increase in birefringence of the external membrane induced by these dyes. It is particularly those dyes that act as vital dyes that produce a very pronounced increase in the birefringence of the external membrane.

DYE ACCESSIBILITY OF RAYON AND SYNTHETIC FIBERS

Dye accessibility of fiber depends on the magnitudes of the following factors:1. The surface area through which the dye passes into the fiber.2. The speed by which the dye migrates in the fiber.3. The inner volume υ (cc. per lg dry fiber) in which the dye exists.4. The dissociation energy E of the dye-fiber-complex.As (1) and (2) can be calculable when E is known, the author starts the studies from obtainingE. When in the hot and very dilute direct dye solution the sizes of the dye particles are very small and homgeneous, there holds the next relation. (dissociation energy of a dye particle from the dyed fiber) (cal/ particle) Here k: Boltzmann's constant, T: absolute temperature, m0: number of dye particles in the initial dye bath, m: number of dye particles in the equilibrium reaching dye bath, υ: volume of the dye bath.The dyeing experiments are as follows.Materials to be dyed; viscose rayon, cuprammonium rayon, Vinylon (appolyvinylformal fiber), and polyvinylalcohol fiber. Temperature: 80°C Period: 3 hrs. Liquor ratio: 1/250. Dyes: Benzopurpurine 4BKX Chrysophenine NS Naphthamine Blue 12B (all purified). Dye concentration: 0.001%(Wt) (Benzopurpurine 0.003%) NaCl concentration: 0.001%(Wt) (Benzopurpurine 0.0003%) The results are:Under the same dyeing condition E of Vinylon is found to be greater than that of cellulose fiber. but smaller than that of polyvinylalcohol fiber.

The Radiation Decolorization of Dilute Dye Solutions; Chlor Phenol Red1,2

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Radiation Decolorization of Dilute Dye Solutions; Chlor Phenol Red1,2Edward N. Weber and Robert H. SchulerCite this: J. Am. Chem. Soc. 1952, 74, 17, 4415–4418Publication Date (Print):September 1, 1952Publication History Published online1 May 2002Published inissue 1 September 1952https://doi.org/10.1021/ja01137a054RIGHTS & PERMISSIONSArticle Views52Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (465 KB) Get e-Alerts Get e-Alerts

THE PHOTODYNAMIC ACTION OF NEUTRAL RED ON ROOT TIPS OF BARLEY SEEDLINGS. PART I. THE EFFECT ON FREQUENCY OF CELL DIVISION

THE PHOTODYNAMIC ACTION OF NEUTRAL RED ON ROOT TIPS OF BARLEY SEEDLINGS. PART I. THE EFFECT ON FREQUENCY OF CELL DIVISION