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Various azoderivative dyes were incorporated in uncolored poly(vinyl alcohol) (PVOH). One type of film was obtained by drying the layer of solution cast on glass plate. The other type was obtained by rubbing the PVOH layer before complete drying. Linear birefringence and dichroism of dyed polymer films were investigated as a function of stretching degree. An increase in the linear birefringence was found with increasing stretching degree for both uncolored and colored films. Dichroism of the PVOH films depends on the dye chemical structure and also on the stretching degree of both non-rubbed and rubbed and dyed PVOH samples. Molecular modeling was used to examine interactions occurring between PVOH and the embedded dye molecule. These stretching degree dependencies were approximated mathematically, which was used to describe the behavior of some components of interference filters. KEYWORDS blends, dyes/pigments, films, molecular modeling, optics, 1 | INTRODUCTION Dye-containing polymers present both theoretical and practical uses in the development of new products with increased performance. [1] Depending on the properties of the incorporated dye molecules [...]

A new simple colorimetric method for selective determination of arginine was developed using an azobenzothiazole-polyene dye. The benzothiazole moieties of the dye act as dipolar molecular receptors to arginine. Importantly, arginine could be recognized in solution with the naked eye due to the color change from orange to blue. Reproducibility of the assays was proven by calculating of the intra- and inter-assay variations for the color responses and the variations were found to be 6.9 and 4.2%, respectively. Finally, the accurate measurements of arginine in real samples (commercial supplementary medicines) were achieved. In conclusion, validation of the developed method revealed excellent performance characteristics, including long life span, good arginine selectivity among a wide variety of other amino acids and long-term response stability. Keywords: amino acid, sensor, arginine, azo-benzothiazole dye, colorimetry DOI: 10.1134/S1061934816010093, Molecular identification by means of molecularlevel devices is of great scientific interest and intense activity in the many fields of science such as chemistry, biology and sensors [1-5]. Moreover, the [...]

Vaccines are a triumph of science over infection. They have defeated smallpox, which the World Health Organization declared eradicated in 1980, and dramatically lowered the toll of many other infectious [...]

Used as a blue emitter, fluorescent dye 4,4'-bis(9-ethyl-3-carbazovinylene)1,1'-biphenyl (BCzVBi) is compounded with Bis[2-(2-hydroxyphenylj-pyridinejberyllium([Bepp.sub.2]j to yield high efficiency. When combined with green and red phosphorescent emitting layers, a broad band white light organic light-emitting diodes are obtained and studied. In this device, both singlet and triplet excitons can be harvested to generate white color. Through device structure optimization, a high efficiency of 20.8 cd/A, which corresponds to an external quantum efficiency of 11.3% has been achieved. PACS Nos.: 78.55.-m, 73.50.Gr, 85.30.-2. Utilise comme emetteur dans le bleu, le colorant fluorescent 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi) est associe a du Bis[2-(2-hydroxyphenyl)-pyridinejberyllium([Bepp.sub.2]) pour atteindre un haut rendement. En combinant avec des couches phosphorescentes dans le rouge et le vert, nous obtenons et etudions des DELO a large bande dans le blanc. Dans ce dispositif, on peut recolter a la fois des excitons singlets et triplets pour generer la couleur blanche. En optimisant la structure du dispositif, nous obtenons une haute efficacite de 20,8 cd/A, ce qui se traduit par une efficacite quantique externe de 11.3%. [Traduit par la Redaction], 1. Introduction High efficiency white organic light-emitting diodes (WOLEDs) are considered the next generation of technology for flat-panel or flexible displays [1, 2] and have great potential for energy saving [...]

Glycomic analysis is an increasingly important field in biological and biomedical research as glyeosylation is one of the most important protein post-translational modifications. We have developed a new technique to detect carbohydrates using surface enhanced Raman spectroscopy (SERS) by designing and applying a Rhodamine B derivative as the SERS tag. Using a reductive amination reaction, the Rhodamine-based tag (RT) was successfully conjugated to three model carbohydrates (glucose, lactose, and glucuronic acid). SERS detection limits obtained with a 633 nm HeNe laser were ~1 nM in concentration for all the RT-carbohydrate conjugates and ~10 fmol in total sample consumption. The dynamic range of the SERS method is about 4 orders of magnitude, spanning from 1 nM to 5 [micro]M. Ratiometric SERS quantification using isotope-substituted SERS internal references allows Comparative quantifications of carbohydrates labeled with RT and deuterium/hydrogen substituted RT tags, respectively. In addition to enhancing the SERS detection of the tagged carbohydrates, the Rhodamine tagging facilitates fluorescence and mass spectrometric detection of carbohydrates. Current fluorescence sensitivity of RT-carbohydrates is ~3 nM in concentration while the mass spectrometry (MS) sensitivity is about 1 fmol, achieved with a linear ion trap electrospray ionization (ESI)-MS instrument. Potential applications that take advantage of the high SERS, fluorescence, and MS sensitivity of this SERS tagging strategy are discussed for practical glycomic analysis where carbohydrates may be quantified with a fluorescence and SERS technique and then identified with ESI-MS techniques. 10.1021/ac102284x

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2008.11.017 Byline: V.K. Gupta (a), Suhas (b) Abstract: Dyes are an important class of pollutants, and can even be identified by the human eye. Disposal of dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. The growing demand for efficient and low-cost treatment methods and the importance of adsorption has given rise to low-cost alternative adsorbents (LCAs). This review highlights and provides an overview of these LCAs comprising natural, industrial as well as synthetic materials/wastes and their application for dyes removal. In addition, various other methods used for dye removal from water and wastewater are also complied in brief. From a comprehensive literature review, it was found that some LCAs, in addition to having wide availability, have fast kinetics and appreciable adsorption capacities too. Advantages and disadvantages of adsorbents, favourable conditions for particular adsorbate-adsorbent systems, and adsorption capacities of various low-cost adsorbents and commercial activated carbons as available in the literature are presented. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed. Author Affiliation: (a) Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, India (b) Centro de Quimica de Evora and Departmento de Quimica, Universidade de Evora, Colegio Luis Antonio Verney, 7000-671 Evora, Portugal Article History: Received 23 June 2008; Revised 8 November 2008; Accepted 24 November 2008

A new binding assay for a protein and its ligand based on a spectroelectrochemical method was demonstrated using avidin--biotin and 17[beta]-estradiol--antiestradiol antibody. The sensor consists of a selective film coated on an optically transparent electrode (OTE) consisting of indium tin oxide (ITO). Attenuated total reflection (ATR) was used for optical detection. The binding event of the ligand to the protein was detected using the ligand labeled with the electroactive dye Nile blue (NB). The spectroelectrochemical behaviors of NB and the labeled ligand were investigated using various ion-exchange films, such as perfluorosulfonated ionomer (Nafion), Nation-silica, poly(acrylic acid) (PAA)-silica, poly(styrenesulfonic acid) (PSSA)-silica, and heparin-silica films, which were spin-coated on the ITO electrode. The optical signal was monitored to follow the accumulation of labeled ligand in the film and its electrochemical modulation. The signal from the labeled ligand possesses three modes of selectivity based on charge-selective partitioning, the chosen electrolysis potential, and the particular wavelength for measuring absorbance. The interaction between the labeled ligand and its protein was observed by the decrease in the changes of optical response of the labeled ligand, indicating the specific binding of labeled ligand to the protein.

The dye-sensitized solar cells (DSC) were assembled by using natural dyes extracted from black rice, capsicum, erythrina variegata flower, rosa xanthina, and kelp as sensitizers. The [I.sub.Sc] from 1.142 mA to 0.225 mA, the [V.sub.OC] from 0.551 V to 0.412 V, the fill factor from 0.52 to 0.63, and [P.sub.max] from 58 [micro]W to 327 [micro]W were obtained from the DSC sensitized with natural dye extracts. In the extracts of natural fruit, leaves and flower chosen, the black rice extract performed the best photosensitized effect, which was due to the better interaction between the carbonyl and hydroxyl groups of anthocyanin molecule on black rice extract and the surface of Ti[O.sub.2] porous film. The blue-shift of absorption wavelength of the black rice extract in ethanol solution on Ti[O.sub.2] film and the blue-shift phenomenon from absorption spectrum to photoaction spectrum of DSC sensitized with black rice extract are discussed in the paper. Because of the simple preparation technique, widely available and low cheap cost natural dye as an alternative sensitizer for dye-sensitized solar cell is promising. Keywords: Dye-sensitized solar cell; Natural dye; Photosensitizer; Black rice; Anthocyanin; Nanocrystalline Ti[O.sub.2] porous film; Fill factor; Natural pigment

Persistent spectral nonphotochemical hole-burning (NPHB) spectroscopy has recently been applied to dye molecules in cells. The sensitivity of NPHB to the nanoenvironment of the probe is well established. It has been shown that NPHB applied to bulk suspensions of cultured human cells can distinguish between normal and cancer cells. Thus, NPHB has potential as a diagnostic cancer tool. For this reason, the methodology is referred to as hole-burning imaging, by analogy with MRI. The optical dephasing time ([T.sub.2]) of the dye in hole-burning image replaces the proton [T.sub.1] relaxation time in MRI. In addition to the [T.sub.2] mode of operation, there are four other modes including measurement of the spectral hole growth kinetics (HGK). Reported here is that the selectivity and sensitivity of NPHB operating in the HGK mode allow for distinction between normal and carcinoma cells at the single-cell level. The ovarian cell lines are ovarian surface epithelial cells with temperature-sensitive large T antigens (analogously normal) and ovarian surface epithelial carcinoma (OV167) cells. The mitochondrial specific dye used was rhodamine 800 (Molecular Probes). This carbocationic dye is highly specific for the outer and inner membranes of mitochondria. In line with the results for bulk suspensions of the two cell lines, the hole-burning efficiency for OV167 cells was found to be significantly higher than that for normal cells. Theoretical analysis of the HGK data leads to the conclusion that the degree of structural heterogeneity for the probe--host configurations in OV167 cells is lower than in the normal cells. Possible reasons for this are given.

Objective. The use of antibacterial agents to clean and dry the stump of the newborn's umbilical cord after birth has recently been abandoned by many neonatal units in favor of dry cord care. The objective of this study was to compare cord bacterial colonization and morbidity among newborns whose cords were treated with triple dye and alcohol versus dry cord care. Methodology. We randomly allocated 766 newborns to either 2 applications of triple dye to the umbilical cord stump on the day of birth with alcohol swabbing twice daily until the cord fell off (n = 384) or dry care (n = 382). Dry care consisted of spot cleaning soiled skin in the periumbilical area with soap and water, wiping it with a dry cotton swab or cloth, and allowing the area to air dry. Umbilical stumps on all subjects were swabbed and cultured. Community health nurses visiting at 2 or 3 days after hospital discharge observed the stump for signs of infection. Follow-up phone calls were made to mothers within 3 weeks of discharge. Results. One infant in the dry care group was diagnosed with omphalitis. The umbilical stump was colonized with [alpha]-hemolytic streptococcus and coagulase-negative staphylococcus. Infants in the dry care group were significantly more likely to be colonized with Escherichia coli (34.2% vs 22.1%), coagulase-negative staphylococci (69.5% vs 50.5%), Staphylococcus aureus (31.3% vs 2.8%), and group B streptococci (11.7% vs 6.0%). Community health nurses were significantly more likely to observe exudate (7.4% vs 0.3%) and foul odor (2.9% vs 0.7%) among infants allocated to the dry care group during the home visit. Conclusions. Omphalitis remains a clinical issue. Cessation of bacteriocidal care of the umbilical stump must be accompanied by vigilant attention to the signs and symptoms of omphalitis. Pediatrics 2003;111:15-20; umbilical cord, omphalitis, Staphylococcus aureus, infection, colonization, randomized controlled trial., Epidemics of staphylococcus infections in the nurseries in the 1950s have given rise to bactericidal treatment of the umbilical cord stump as a standard of care. Staphylococcus aureus is a [...]

We focus on the fabrication and study of controllable holographic gratings based on azo-dye-doped and undoped polymer-ball-type polymer-dispersed liquid-crystal films. Experimental results indicate that the next step of photopolymerization of the sample with the illumination of [Ar.sup.+] laser beams after UV curing causes a latent density grating to be recorded. This grating is formed by a selective secondary photopolymerization. Heating and applying a voltage change the structure of the liquid crystal and induce the appearance of the latent grating. Diffraction efficiencies versus temperature, voltage, and state of polarization are studied for both dye-doped and undoped cells and are found to be quite different. This discrepancy is attributable to the reorientation effect of liquid crystals through their interaction with the photo-induced adsorption of the doped dyes on the surface of polymer balls in the dye-doped cell.

The aim was to devise a method for the measurement of total surface area and weight, as well as saliva weight, for a gelatin-based confectionery gel over the course of human mastication for input into separate modelling of flavour release. The method is based on an alcohol rinse to remove saliva, followed by immersion in amaranth dye to give a thin surface dye layer coating the gel fragments. Total surface area is then found by measurement of quantity of absorbed dye. The resulting time profiles for the six panellists showed that surface area reached a maximum of 3000 [mm.sup.2] with the 4.28 g gel weight being consumed over 41 to 64 sec with differing numbers of swallows (4-6) and chews (52-103). Calculated total relative saliva weights, 498-993 g [kg.sup.-1], and flow rates, 2.8-5.6g [min.sup.-1], were towards the upper range of those reported in the literature.

Some characteristics of dyed gelatin films when polarization gratings are recorded are reported. Two dyes, Malachite Green and Methylene Blue, are used in our experiment. In particular, no dichromate was added to Methylene Blue plates before or after exposure. It is shown that, in spite of its having high viscosity, a relief grating is formed when orthogonal linearly polarized beams are superimposed upon the plates. In contrast with previous observations in another photoanisotropic medium, the frequency of the gelatin relief grating does not depend on the directions of the electric field of the orthogonal recording beams. Besides, when orthogonal circularly polarized beams are used in the formation of polarization gratings, no relief grating is produced. Finally, we study the phase modulation obtained after dehydration of the gelatin plates in which the polarization gratings were formed. Postdevelopment phase gratings do not preserve the polarization information of the interference pattern. Also, the grating frequency is increased by a factor of 2 for linear polarization, whereas for circular polarization there is no phase modulation.

A sequential ion-sensing system using a single microchip was successfully realized. The system developed here involves intermittent pumping of plural organic phases into a microchannel, followed by contact with a single aqueous phase to form a stable organic--aqueous two-layer flow inside the microchannel. Because the plural organic phases created by intermittent flow contain the same lipophilic pH indicator dye but different ion-selective neutral ionophores, different ions can be sequentially and selectively extracted into the different organic phases, where they can be determined by thermal lens microscopy (TLM). We used KD-A3 as the lipophilic pH indicator dye and valinomycin and DD16C5 as neutral ionophores to demonstrate sequential ion sensing of potassium and sodium ions by measuring the deprotonated dye caused by the ion extraction. The integrated microfluidic system proposed here allows multi-ion sensing, which is not easily demonstrated by conventional ion sensor technology using a solvent polymeric membrane. The minimum volume of single organic phase needed to obtain an equilibrium response without dilution by cross dispersion of two organic phases was ca. 500 nL in our system, indicating that the required amounts of expensive reagents in one measurement could be reduced to 1.7 ng and 2.8 ng for the dye and ionophore molecules, respectively.

Byline: Hironori Ishihara (1), Akiko Suzuki (1), Hirobumi Okawa (1), Ichiro Sakai (1), Toshihito Tsubo (1), Akitomo Matsuki (1) Keywords: Measurement techniques Glucose Indocyanine green Plasma volume Distribution volume Extracellular fluid Abstract: Objectives: To determine whether the initial distribution volume of glucose (IDVG) rather than plasma volume or blood volume is correlated better with cardiac output during the 4 days following major surgery. Design and setting: Prospective clinical investigation in the general intensive care unit of a university hospital. Patients and methods: 31 consecutive patients who underwent radical surgery for esophageal carcinoma were enrolled. Continuous thermodilution cardiac output monitor was placed in the operating room. Indocyanine green (ICG 25 mg) and glucose (5 g) were administered simultaneously to calculate IDVG and plasma volume determined using the ICG dilution method. Blood volume was also calculated from plasma volume ICG and hematocrit. Those volumes were measured on admission to the ICU and daily on the first 3 postoperative days. The relationships between each volume and cardiac index (CI), and between routine clinical variables and CI were evaluated. Results: IDVG had a linear correlation with CI in the early postoperative days (r=0.71, n=124, p Conclusions: Our results indicate that IDVG rather than intravascular volume is correlated with cardiac output. We suggest that IDVG has potential as an alternative indicator of cardiac preload following major surgery. Author Affiliation: (1) Department of Anesthesiology, University of Hirosaki School of Medicine, 5 Zaifu-Cho, Hirosaki-Shi, 036-8562 Japan Article History: Received Date: 03/04/2000 Accepted Date: 03/08/2000 Article note: Final revision received: 31 July 2000 Electronic Publication

The influence of mobile phase on the lateral diffusion of an amphiphilic dye was studied for four chromatographic interfaces using fluorescence correlation spectroscopy. The fluorescent dye was DiI (1,1'-dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine perchlorate); the stationary phase was a covalently bonded monolayer of dimethyloctadecylsiloxane on fused silica; and the four mobile phases were acetonitrile, methanol, tetrahydrofuran, and water. Time-resolved measurements at varying focal positions of the microscope confirmed negligible fluorescence from solution. Single-molecule spectroscopy showed that exchange between mobile and immobile adsorbates was negligible. The lateral diffusion of DiI was the fastest for tetrahydrofuran, D = 5.3 x 10(super -5) cm(super 2)/s, and slowest for water, D = 2.5 x 10(super -6) cm(super 2)/s. Methanol and acetonitrile gave intermediate rates of diffusion, D = 3.4 x 10(super -6) and 4.8 x 10(super -6), respectively. There was no correlation of the lateral diffusion coefficient with solvent viscosity, a weak correlation with interfacial tension, and a strong correlation with (super 13)C NMR line shapes for the terminal methyl group of the hydrocarbon chain. The increased wetting of the C(sub 18) interphase in the order water < methanol < acetonitrile < tetrahydrofuran agreed with data for the miscibility of these solvents with n-hexadecane. It is concluded that the wetting of the hydrocarbon interphase by the mobile phase enhances the lateral diffusion of the amphiphile.

Dyes are useful tools for revealing flow patterns, but because analysis of dyes is time-consuming and often only qualitative, soil scientists have not used them to their full advantage. We developed a method for discriminating dyed from undyed soil in the field and for determining the dye concentration from point to point. The method requires a 35-mm camera, a specially constructed camera stand for uniform illumination during field work, and a color scanner. Working with Brilliant Blue FCF dye on a gray (chroma of one) soil, we determined dye concentrations 2.0 g [L.sup.-1]. analysis was more problematic due to dye precipitating out of solution onto the soil surface, but we obtained an [r.sup.2] of 0.70. Use of this method allows convenient and rapid quantitative analysis of dye concentration and other color contrast patterns.

Dyes are often used as tracers of water and solute flow in soil. However, there has been little published research on the effects of flow velocity on the relative movement of dye and wetting fronts. Recently, the FD&C Blue no. 1 dye has been used as a tracer of preferential water flow paths in soils, and has attractive properties suggesting it will be used increasingly in the future. The objective of this study was to characterize the effects of flow velocity on the adsorption characteristics of the FD&C Blue no. 1. We performed a series of laboratory experiments on the characterization of the equilibrium adsorption isotherm as well as the effect of flow velocity on adsorption characteristics of the FD&C Blue no. I in three horizons of Verndale sandy loam (coarse-loamy over sandy, mixed, frigid Udic Argiboroll). Batch equilibration (24 h) measurements resulted in linearized Freundlich distribution coefficients ([K.sub.d]) of 4.33, 23.95, and 4.59 L [kg.sup.-1] for the Ap, Bt, and C horizons, respectively. Neither organic C nor clay content differences accounted for the variation between horizons. Leaching experiments with a 1 g [L.sup.-1] dye solution and repacked soil columns containing either Ap, Bt, or C horizon material showed that the dye was retarded relative to the wetting front, and that the extent of retardation was inversely related to the time period during which dye solution was applied. Therefore, this dye (and perhaps others) should not be used to make inferences about the movement of water or other solutes until the effect of the application rate is evaluated for the flow conditions in the system(s) of interest.

Clock reaction kinetic studies are effective ways to explain complex reaction methods in undergraduate chemistry classes and can be performed as demonstrations or student experiments. The simple clock reaction between methylene blue and L-ascorbic acid, or vitamin C, provides a visible color change. Experiment directions are included. As a demonstration, only 3-4 minutes are required while the experiment requires under 1/2 hour.

Color photo development can be achieved through dye-coupled, dye-transfer and dye-bleaching processes, all of which use silver salts in film emulsion. The dye-coupled process is the most widely used in modern times. The dye-transfer method is extensively applied in instant photography while dye-bleaching is popular because the finished pictures prepared through this method are resistant to the degradation of dye on storage. A fourth method which does not utilize silver salts is electronic photography. It is still not widely used but is foreseen to gain popularity in the future.

The purpose of this study is to decrease PD at a triple junction by addition of a dye to an insulating material. PD is produced on a test specimen subjected to ac voltage under a sphere-plane electrode configuration. The specimen is composed of two layers: a PMMA film with additive, which is 100 [[micro]meter] thick; the lower layer a PMMA board 3 mm thick. The film with the additive was prepared by the solution-grown casting method. Five kinds of dye were used as the additive; p-aminoazobenzene (Ab), p-nitrobenzeneazoresorcinol (Nb), methyl yellow (My), methylene blue (Mb) and methyl red (Mr). In the case of the films with Ab and Mb at 0.05% wt, the magnitude and number of PD pulses were reduced to [approximately] 50% less than those in the case of the films without the additive. The decrease in PD was effective under an electric field strength slightly higher than the PD inception. In the case of the other dyes, decrease in PD was not observed. The surface voltage distribution due to the charge by PD depended on the kind of dye additive. The decrease in PD for the Ab and Mb films was explained from the dependence of the surface voltage distribution on the dye. It was concluded that ionization of the dye molecules in the film changes the distribution of surface voltage.

Flow cytometric analyses are conducted for cultures of Escherichia coli and a variety of marine prokaryotes using novel blue light-excited fluorescent dyes for nucleic acid. Results suggest that the dyes are very sensitive to ionic strength, making them unsuitable for cell cycle analysis in natural samples. However, the dyes are very useful for enumerating prokaryotic cells by flow cytometry.

Four methods to determine the cation-exchange capacities (CEC) of sous and clays were evaluated: (i) conventional [NH.sub.4]-NA exchange, (ii) methylene blue (MB) capacity with MB acid, (iii) CEC of tetrasodium pyrophosphate (TSPP), and (iv) MB-water filter paper spot test titration methods. Eighteen surface soils (0-15 cm) from farm fields in Taiwan and four reference clays obtained from the Source Clay Repository (Clay Minerals Society, Columbia, MO) were used in this work. Under appropriate conditions of concentration, equilibration period, and flocculation of MB solutions, MB absorption can be used to determine the CEC of soils and clays. Regression analyses gave [R.sup.2] values 0.91, 0.99, and 0.74 for MB-acid, MB-TSPP, and MB-water titration methods, respectively, vs. [NH.sub.4]-NA exchange. The CEC values of MB-TSPP titration showed a good linear correlation with values from the [NH.sub.4]-NA exchange method. Thus, the method of MB-TSPP filer paper spot-test titration is recommended for rapid CEC determination in field test of soils.

The veratryl alcohol (VA) assay is the routine procedure used to detect and quantify lignin peroxidase activity. These assays are limited by the possibilities of end product reduction by the fungus, low sensitivity and their proneness to interference from ultraviolet and short-wavelength visible-light absorbing materials. A new procedure, using the dye Azure B, has been developed. This procedure is as simple and rapid as the VA assays but is not as prone to their shortcomings.

A new screening process for detecting exopolysaccharide-deficient mutants that do not require Calcofluor binding was discovered. The technique may be applied for the isolation of mutants of Rhizobium meliloti that do not have normal production of either succinoglycan or galactoglucan. Exopolysaccharide-producing strains of R. meliloti were observed to exclude the lipophilic dye Sudan Black B, while exoB mutants which do not synthesize succinoglycan and galactoglucan readily accepted the dye.

The tuning characteristics of a Coumarine 460-Disodium Fluorescein-Rhodamine 640 dye-mixture laser in the blue, green, and yellow-orange regions are reported. A linear variable filter was inserted into the laser cavity as a tuning element. The tunable range was 439-485 nm in the blue region, 509-531 nm in the green region, and 592-601 nm in the yellow-orange region. Comparison of the characteristics of the one-wavelength tuning output with those of simultaneous broadband outputs in the three color regions showed that energy transfer was an important mechanism for the oscillations, especially in the longer-wavelength region, which was farthest away from a pumping wavelength.

Kenyan textile manufacturers, who had been relying on imported dyes so far, can look forward to substantially lower their operational costs by using a newly invented natural dye. The textile [...]