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Sample records for crystal violet dye

  1. Measuring the Photocatalytic Breakdown of Crystal Violet Dye using a Light Emitting Diode Approach

    NASA Technical Reports Server (NTRS)

    Ryan, Robert E.; Underwood, Lauren W.; O'Neal, Duane; Pagnutti, Mary; Davis, Bruce A.

    2009-01-01

    A simple method to estimate the photocatalytic reactivity performance of spray-on titanium dioxide coatings for transmissive glass surfaces was developed. This novel technique provides a standardized method to evaluate the efficiency of photocatalytic material systems over a variety of illumination levels. To date, photocatalysis assessments have generally been conducted using mercury black light lamps. Illumination levels for these types of lamps are difficult to vary, consequently limiting their use for assessing material performance under a diverse range of simulated environmental conditions. This new technique uses an ultraviolet (UV) gallium nitride (GaN) light emitting diode (LED) array instead of a traditional black light to initiate and sustain photocatalytic breakdown. This method was tested with a UV-resistant dye (crystal violet) applied to a titanium dioxide coated glass slide. Experimental control is accomplished by applying crystal violet to both titanium dioxide coated slides and uncoated control slides. A slide is illuminated by the UV LED array, at various light levels representative of outdoor and indoor conditions, from the dye side of the slide. To monitor degradation of the dye over time, a temperature-stabilized white light LED, whose emission spectrum overlaps with the dye absorption spectrum, is used to illuminate the opposite side of the slide. Using a spectrometer, the amount of light from the white light LED transmitted through the slide as the dye degrades is monitored as a function of wavelength and time and is subsequently analyzed. In this way, the rate of degradation for photocatalytically coated versus uncoated slide surfaces can be compared. Results demonstrate that the dye absorption decreased much more rapidly on the photocatalytically coated slides than on the control uncoated slides, and that dye degradation is dependent on illumination level. For photocatalytic activity assessment purposes, this experimental configuration and

  2. An LED Approach for Measuring the Photocatalytic Breakdown of Crystal Violet Dye

    NASA Technical Reports Server (NTRS)

    Ryan, Robert E.; Underwood, Lauren W.; ONeal, Duane; Pagnutti, Mary; Davis, Bruce A.

    2009-01-01

    A simple technique to assess the reactivity of photocatalytic coatings sprayed onto transmissive glass surfaces was developed. This new method uses ultraviolet (UV) gallium nitride (GaN) light-emitting diodes (LEDs) to drive a photocatalytic reaction (the photocatalytic breakdown of a UV-resistant dye applied to a surface coated with the semiconductor titanium dioxide); and then a combination of a stabilized white light LED and a spectrometer to track the dye degradation as a function of time. Simple, standardized evaluation techniques that assess photocatalytic materials over a variety of environmental conditions, including illumination level, are not generally available and are greatly needed prior to in situ application of photocatalytic technologies. To date, much research pertaining to this aspect of photocatalysis has been limited and has focused primarily on laboratory experiments using mercury lamps. Mercury lamp illumination levels are difficult to control over large ranges and are temporally modulated by line power, limiting their use in helping to understand and predict how photocatalytic materials will behave in natural environmental settings and conditions. The methodology described here, using steady-state LEDs and time series spectroradiometric techniques, is a novel approach to explore the effect of UV light on the photocatalytic degradation of a UV resistant dye (crystal violet). GaN UV LED arrays, centered around 365 nm with an adjustable DC power supply, are used to create a small, spatially uniform light field where the steady state light level can be varied over three to four orders of magnitude. For this study, a set of glass microscope slides was custom coated with a thinly sprayed layer of photocatalytic titanium dioxide. Crystal violet was then applied to these titanium-dioxide coated slides and to uncoated control slides. The slides were then illuminated at various light levels from the dye side of the slide by the UV LED array. To monitor

  3. Radiochromic leuco dye micelle hydrogels: II. Low diffusion rate leuco crystal violet gel

    NASA Astrophysics Data System (ADS)

    Babic, Steven; Battista, Jerry; Jordan, Kevin

    2009-11-01

    Radiation-sensitive hydrogels offer the capability of verifying intricate dose distributions in three-dimensional (3D) space conveniently in a single measurement with sub-millimetre spatial resolution. In this study, a new radiochromic hydrogel called leuco crystal violet (LCV) micelle gel is introduced. Upon irradiation, LCV converts to crystal violet (CV+). Triton X-100 micelles are used to provide the required hybrid-interfacing environment to dissolve LCV. The diffusion coefficient of the LCV gel has been measured to be 0.036 ± 0.001 mm2 h-1, which is a factor of 25 times less than the standard radiochromic ferrous xylenol-orange (FX) gel; LCV gels without Triton X-100 micelles have a diffusion coefficient of 0.33 ± 0.02 mm2 h-1. The LCV gel formulation contains: 1 mM LCV, 25 mM trichloroacetic acid, 4 mM Triton X-100 and 4% w/w gelatin. The primary innovative feature of this 3D hydrogel is that the radiation-induced CV+ dye is more soluble in the Triton X-100 micelles than in the surrounding water which consequently leads to more stable post-irradiation dose distributions. A dosimetric characterization revealed that the dose response is reproducible to within 1% over three separate batches, independent of energy, dose rate and dose fractionation but is affected by the temperature (~4% per °C) during irradiation. LCV micelle gels scanned optically with a yellow light source are a promising system for 3D dose verification. They may prove to be, especially, useful for scanning large volume dosimeters (i.e. 20 cm) since they are easily manufactured, transparent and near colourless prior to irradiation.

  4. Study of Surface Enhanced Raman Scattering of Alizarin and Crystal Violet Dyes

    NASA Astrophysics Data System (ADS)

    Gopal, Ram; Swarnkar, Raj Kumar

    2010-06-01

    Surface enhanced Raman scattering (SERS) plays a vital role in analytical chemistry to characterize ultra trace quantity of organic compounds and biological samples. Two mechanisms have been considered to explain the SERS effect. The main contribution arises from a huge enhancement of the local electromagnetic field close to surface roughness of the metal structures, due to the excitation of a localized surface plasmon, while a further enhancement can be observed for molecules adsorbed onto specific sites when resonant charge transfer occurs. SERS signals have been observed from adsorbates on many metallic surfaces like Ag, Au, Ni, Cu etc. Additionally, metal oxide nanoparticles also show SERS signals It has now been established that SERS of analyte material is highly dependent on the type of substrate involved. Many types of nanostructures like nanofilms, nanorods, nanospheres etc. show highly efficient SERS signals. In particular, there are two routes available for the synthesis of these nanomaterials: the chemical route and the physical route. Chemical route involves many types of reducing agents and capping agents which can interfere in origin and measurement of these signals. The physical route avoids these anomalies and therefore it is suitable for the study of SERS phenomenon. Pulsed laser ablation in liquid medium is an excellent top down technique to produce colloidal solution of nanoparticles with desired shape and size having surface free from chemical contamination, which is essential requirement for surface application of nanoparticles. The present work deals with the study of SERS of Crystal violet dye and Alizarin group dye on Cu@ Cu_2O and Ag colloidal nanoparticles synthesized by pulsed laser ablation. M. Fleishchmann, P. J. Hendra, and A. J. McQuillian Chem. Phys. Lett., 26, 163, 1974. U. Wenning, B. Pettinger, and H. Wetzel Chem. Phys. Lett., 70, 49, 1980. S. C. Singh, R. K. Swarnkar, P. Ankit, M. C. Chattopadhyaya, and R. Gopal AIP Conf. Proc

  5. Investigations on the growth, optical, thermal, dielectric, and laser damage threshold properties of crystal violet dye-doped potassium acid phthalate single crystal

    NASA Astrophysics Data System (ADS)

    Rao, G. Babu; Rajesh, P.; Ramasamy, P.

    2016-03-01

    Influence of crystal violet dye with different concentration on potassium acid phthalate single crystal grown by conventional method has been studied. No change has been observed in the structure, whereas changes have been observed in the external morphology of the crystal when the dyes are incorporated in the crystal lattice. Thermogravimetric and differential thermal analyses show the onset decomposition temperatures to be at 302, 285, 284, and 285 °C for pure, 0.1, 0.3, and 0.5 mol% crystal violet-doped potassium acid phthalate crystals, respectively. The dielectric measurement was carried out on the grown crystals as a function of frequency at various temperatures. In addition, strong luminescent emission bands at 638, 648, and 640 nm were observed in which the relative intensity was found to be reversed as a result of doping concentration. The laser damage threshold value significantly increased for dye-doped crystal in comparison with pure crystal which may make it suitable for the solid-state dye laser applications.

  6. Response surface optimization of a dynamic dye adsorption process: a case study of crystal violet adsorption onto NaOH-modified rice husk.

    PubMed

    Chowdhury, Shamik; Chakraborty, Sagnik; Saha, Papita Das

    2013-03-01

    The adsorption of crystal violet from aqueous solution by NaOH-modified rice husk was investigated in a laboratory-scale fixed-bed column. A two-level three factor (2(3)) full factorial central composite design with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for optimisation of the dynamic dye adsorption process and evaluation of interaction effects of different operating parameters: initial dye concentration (100-200 mg L(-1)), flow rate (10-30 mL min(-1)) and bed height (5-25 cm). A correlation coefficient (R (2)) value of 0.999, model F value of 1,936.59 and its low p value (<0.0001) along with lower value of coefficient of variation (1.38 %) indicated the fitness of the response surface quadratic model developed during the present study. Numerical optimisation applying desirability function was used to identify the optimum conditions for a targeted breakthrough time of 12 h. The optimum conditions were found to be initial solution pH=8.00, initial dye concentration=100 mg L(-1), flow rate=22.88 mL min(-1) and bed height=18.75 cm. A confirmatory experiment was performed to evaluate the accuracy of the optimised procedure. Under the optimised conditions, breakthrough appeared after 12.2 h and the column efficiency was determined as 99 %. The Thomas model showed excellent fit to the dynamic dye adsorption data obtained from the confirmatory experiment. Thereby, it was concluded that the current investigation gives valuable insights for designing and establishing a continuous wastewater treatment plant. PMID:22648351

  7. Crystal violet: Study of the photo-fading of an early synthetic dye in aqueous solution and on paper with HPLC-PDA, LC-MS and FORS

    NASA Astrophysics Data System (ADS)

    Confortin, Daria; Neevel, Han; Brustolon, Marina; Franco, Lorenzo; Kettelarij, Albert J.; Williams, Renè M.; van Bommel, Maarten R.

    2010-06-01

    The photo-fading of crystal violet (CV), one of the earliest synthetic dyes and an ink component, is examined both in solution and on paper. Aqueous solutions of CV were exposed to UV light (365nm) and samples were taken at constant time intervals and analysed with a High Performance Liquid Chromatography-Photo Diode Array (HPLC-PDA) and Liquid Chromatography-Mass Spectroscopy (LC-MS). Demethylation products were positively identified. Also, deamination probably occurred. The oxidation at the central carbon likely generates Michler's ketone (MK) or its derivatives, but still needs confirmation. To study CV on paper, Whatman paper was immersed in CV and exposed to UV light. Before and after different irradiation periods, reflectance spectra were recorded with Fibre Optic Reflectance Spectrophotometry (FORS). A decrease in CV concentration and a change in aggregation type for CV molecules upon irradiation was observed. Colorimetric L*a*b* values before and during irradiation were also measured. Also, CV was extracted from paper before and after different irradiation periods and analysed with HPLC-PDA. Photo-fading of CV on paper produced the same products as in solution, at least within the first 100 hours of irradiation. Finally, a photo-fading of CV in the presence of MK on Whatman paper was performed. It was demonstrated that MK both accelerates CV degradation and is consumed during the reaction. The degradation pathway identified in this work is suitable for explaining the photo/fading of other dyes belonging to the triarylmethane group.

  8. Crystal Violet Assay for Determining Viability of Cultured Cells.

    PubMed

    Feoktistova, Maria; Geserick, Peter; Leverkus, Martin

    2016-01-01

    Adherent cells detach from cell culture plates during cell death. This characteristic can be used for the indirect quantification of cell death and to determine differences in proliferation upon stimulation with death-inducing agents. One simple method to detect maintained adherence of cells is the staining of attached cells with crystal violet dye, which binds to proteins and DNA. Cells that undergo cell death lose their adherence and are subsequently lost from the population of cells, reducing the amount of crystal violet staining in a culture. This protocol describes a quick and reliable screening method that is suitable for the examination of the impact of chemotherapeutics or other compounds on cell survival and growth inhibition. However, characterization of the cause of reduced crystal violet staining requires additional methods detailed elsewhere. PMID:27037069

  9. Biodegradation of crystal violet by Agrobacterium radiobacter.

    PubMed

    Parshetti, G K; Parshetti, S G; Telke, A A; Kalyani, D C; Doong, R A; Govindwar, S P

    2011-01-01

    Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr (10 mg/L) at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition (10 mg/L). When the effect of increasing inoculum concentration on decolorization of Crystal Violet (100 mg/L) was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase (184%) and aminopyrine N-demethylase (300%) in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy (GC/MS). It was detected the presence of N,N,N',N"-tetramethylpararosaniline, [N, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria (A. radiobacter, P. aurugenosa and A. vinelandii) contributing to soil fertility and for four kinds of plants (Sorghum bicolor Vigna radiata, Lens culinaris and Triticum aestivum) which are most sensitive, fast growing and commonly used in Indian agriculture. PMID:22128547

  10. Biodegradation of crystal violet by the white rot fungus Phanerochaete chrysosporium.

    PubMed Central

    Bumpus, J A; Brock, B J

    1988-01-01

    Biodegradation of crystal violet (N,N,N',N',N'',N''-hexamethylpararosaniline) in ligninolytic (nitrogen-limited) cultures of the white rot fungus Phanerochaete chrysosporium was demonstrated by the disappearance of crystal violet and by the identification of three metabolites (N,N,N',N',N''-pentamethylpararosaniline, N,N,N',N''-tetramethylpararosaniline, and N,N',N''-trimethylpararosaniline) formed by sequential N-demethylation of the parent compound. Metabolite formation also occurred when crystal violet was incubated with the extracellular fluid obtained from ligninolytic cultures of this fungus, provided that an H2O2-generating system was supplied. This, as well as the fact that a purified ligninase catalyzed N-demethylation of crystal violet, demonstrated that biodegradation of crystal violet by this fungus is dependent, at least in part, upon its lignin-degrading system. In addition to crystal violet, six other triphenylmethane dyes (pararosaniline, cresol red, bromphenol blue, ethyl violet, malachite green, and brilliant green) were shown to be degraded by the lignin-degrading system of this fungus. An unexpected result was the finding that substantial degradation of crystal violet also occurred in nonligninolytic (nitrogen-sufficient) cultures of P. chrysosporium, suggesting that in addition to the lignin-degrading system, another mechanism exists in this fungus which is also able to degrade crystal violet. PMID:3389809

  11. Simultaneous removal of binary mixture of Brilliant Green and Crystal Violet using derivative spectrophotometric determination, multivariate optimization and adsorption characterization of dyes on surfactant modified nano-γ-alumina

    NASA Astrophysics Data System (ADS)

    Zolgharnein, Javad; Bagtash, Maryam; Shariatmanesh, Tahere

    2015-02-01

    The present study deals with the simultaneous removal of Brilliant Green (BG) and Crystal Violet (CV) by surfactant-modified alumina. The utilization of alumina nanoparticles with an anionic surfactant (sodium dodecyl sulfate (SDS)) as a novel and efficient adsorbent is successfully carried out to remove two cationic dyes from aqueous solutions in binary batch systems. A first-order derivative spectrophotometric method is developed for the simultaneous determination of BG and CV in binary solutions. The linear concentration range and limits of detection for the simultaneous determination of BG and CV were found to be: 1-20, 1-15 mg/L, 0.3 and 0.5 mg/L, respectively. The influence of various parameters, such as contact time, initial concentration of dyes and sorbent mass on the dye adsorption is investigated. A response surface methodology achieved through performing the Box-Behnken design is utilized to optimize the removal of dyes by surfactant-modified nanoparticle alumina through a batch adsorption process. The proposed quadratic model resulting from the Box-Behnken design approach fitted very well with the experimental data. The optimal conditions for dye removal were contact time t = 50 min, sorbent dose = 0.036 g, CBG (Initial BG concentration) = 215 mg/L and CCV (Initial CV concentration) = 170 mg/L. Furthermore, FT-IR analysis, the isotherms and kinetics of adsorption were also explored.

  12. Simultaneous removal of binary mixture of Brilliant Green and Crystal Violet using derivative spectrophotometric determination, multivariate optimization and adsorption characterization of dyes on surfactant modified nano-γ-alumina.

    PubMed

    Zolgharnein, Javad; Bagtash, Maryam; Shariatmanesh, Tahere

    2015-02-25

    The present study deals with the simultaneous removal of Brilliant Green (BG) and Crystal Violet (CV) by surfactant-modified alumina. The utilization of alumina nanoparticles with an anionic surfactant (sodium dodecyl sulfate (SDS)) as a novel and efficient adsorbent is successfully carried out to remove two cationic dyes from aqueous solutions in binary batch systems. A first-order derivative spectrophotometric method is developed for the simultaneous determination of BG and CV in binary solutions. The linear concentration range and limits of detection for the simultaneous determination of BG and CV were found to be: 1-20, 1-15 mg/L, 0.3 and 0.5 mg/L, respectively. The influence of various parameters, such as contact time, initial concentration of dyes and sorbent mass on the dye adsorption is investigated. A response surface methodology achieved through performing the Box-Behnken design is utilized to optimize the removal of dyes by surfactant-modified nanoparticle alumina through a batch adsorption process. The proposed quadratic model resulting from the Box-Behnken design approach fitted very well with the experimental data. The optimal conditions for dye removal were contact time t=50 min, sorbent dose=0.036 g, CBG (Initial BG concentration)=215 mg/L and CCV (Initial CV concentration)=170 mg/L. Furthermore, FT-IR analysis, the isotherms and kinetics of adsorption were also explored. PMID:25286114

  13. In situ electrocatalytic oxidation of acid violet 12 dye effluent.

    PubMed

    Mohan, N; Balasubramanian, N

    2006-08-21

    Electrochemical treatment of organic pollutants is a promising treatment technique for substances which are recalcitrant to biodegradation. Experiments were carried out to treat acid violet 12 dye house effluent using electrochemical technique for removal color and COD reduction covering wide range in operating conditions. Ruthenium/lead/tin oxide coated titanium and stainless steel were used as anode and cathode, respectively. The influence of effluent initial concentration, pH, supporting electrolyte and the electrode material on rate of degradation has been critically examined. The results indicate that the electrochemical method can be used to treat dye house effluents. PMID:16730894

  14. [Biosorption of crystal violet and malachite green by Rhodotorula graminis Y-5].

    PubMed

    Hu, Rong; Huang, Jian-Bo; Yang, Zhou-Ping; Cheng, Zi-Zhang; Jing, De-Jun; Huang, Qian-Ming

    2011-12-01

    With a shaker, this paper studied the characteristics of the biosorption of crystal violet and malachite green by Rhodotorula graminis Y-5 under different adsorption time, initial pH, and temperature, as well as the desorption and recycling use of the dyes. The biosorption of crystal violet and malachite green by R. graminis Y-5 had the peaks (93.8% and 87.7%, respectively) at pH 7.0, dye concentration 50 mg x L(-1), 150 r x min(-1), 30 degrees C, and lasting 10 hours. After desorption, the biosorption rate of crystal violet and malachite green by R. graminis was 85.5% and 78.5%, respectively, indicating that the biosorption of crystal violet and malachite green was reversible, and the recycling use of the dyes by R. graminis was quite good, i. e., the dyes were renewable and could be recycled. Biosorption could be the mechanism of the decolorization of the dyes. The dyes were mostly adsorbed on the R. graminis surface -OH. The adsorption process was fast, efficient, and reversible, suggesting that R. graminis had a high potential for waste water treatment. PMID:22384600

  15. Biodegradation of crystal violet by the white rot fungus phanerochaete chrysosporium

    SciTech Connect

    Bumpus, J.A.; Brock, B.J.

    1988-01-01

    Biodegradation of crystal violet (N,N,N',N',N',N''- hexamethylpararosaniline) in ligninolytic (nitrogen-limited) cultures of the white rot fungus Phanerochaete chrysosporium was demonstrated by the disappearance of crystal violet and by the identification of three metabolites (N,N,N',N',N'' -pentamethylpararosaniline, N,N,N',N'' -tetramethylpararosaniline, and N,N',N'' -trimethylpararosaniline) formed by sequential N-demethylation of the parent compound. Metabolite formation also occurred when crystal violet was incubated with the extracellular fluid obtained from ligninolytic cultures of this fungus, provided that an H2O2-generating system was supplied. This, as well as the fact that a purified ligninase catalyzed N-demethylation of crystal violet, demonstrated that biodegradation of crystal violet by this fungus is dependent, at least in part, upon its lignin-degrading system. In addition to crystal violet, six other triphenylmethane dyes (pararosaniline, cresol red, bromphenol blue, ethyl violet, malachite green, and brilliant green) were shown to be degraded by the lignin-degrading system of this fungus.

  16. Oxidation kinetics of crystal violet by potassium permanganate in acidic medium

    NASA Astrophysics Data System (ADS)

    Khan, Sameera Razi; Ashfaq, Maria; Mubashir; Masood, Summyia

    2016-05-01

    The oxidation kinetics of crystal violet (a triphenylmethane dye) by potassium permanganate was focused in an acidic medium by the spectrophotometric method at 584 nm. The oxidation reaction of crystal violet by potassium permanganate is carried out in an acidic medium at different temperatures ranging within 298-318 K. The kinetic study was carried out to investigate the effect of the concentration, ionic strength and temperature. The reaction followed first order kinetics with respect to potassium permanganate and crystal violet and the overall rate of the reaction was found to be second order. Thermodynamic activation parameters like the activation energy ( E a), enthalpy change (Δ H*), free energy change (Δ G*), and entropy change (Δ S*) have also been evaluated.

  17. SERS and DFT study of crystal violet

    NASA Astrophysics Data System (ADS)

    Meng, Wei; Hu, Fang; Zhang, Ling-Yan; Jiang, Xiao-Hong; Lu, Lu-De; Wang, Xin

    2013-03-01

    Six silver colloids were prepared by the reduction of silver nitrate with different amounts of sodium citrate. The obtained silver colloids were characterised by UV-vis spectroscopy, transmission electron microscopy and zeta potential measurements. The surface-enhanced Raman scattering (SERS) activities of these silver colloids were investigated using crystal violet (CV) as a SERS probe. Based on density functional theory (DFT) calculations at the level of B3LYP, the Raman spectra and the optimised geometry of CV were analysed. The results show that the sodium citrate content strongly influences the sizes, zeta potentials and SERS activities of the silver colloids. As the sodium citrate content increases in the preparation of silver colloids, the mean diameters of the silver nanoparticles decrease. The most intense SERS of CV on the silver colloids is obtained when 3 mL of 1% sodium citrate is used. CV has D3 point group symmetry, and the Raman vibrational modes belong to A1 or E irreducible representations. The non-totally symmetric vibrational modes E are selectively enhanced in the SERS of CV through a Herzberg-Teller vibronic coupling mechanism, indicating a considerable charge transfer between CV and the silver nanoparticles.

  18. Multi walled carbon nanotubes as sorbent for removal of crystal violet.

    PubMed

    Kumar, Sandeep; Bhanjana, Gaurav; Dilbaghi, Neeraj; Umar, Ahmad

    2014-09-01

    Carbon nanotubes (CNTs) possess high surface active site to volume ratio as well as controlled pore size distribution that make them high profile material with an exceptional sorption capability and high sorption efficiency compared to conventional adsorbents. In the present paper, multi walled carbon nanotubes were synthesized by chemical vapor deposition (CVD) method and were further used for the removal of dye crystal violet. Microscopic and spectroscopic techniques were used for characterization. The systematic assessments of the pH and effect of adsorbent on different concentrations of dye with respect to contact time were examined. Langmuir and Temkin models were used to describe the isotherm studies. PMID:25924370

  19. Evaluation of the photodegradation of crystal violet upon light exposure by mass spectrometric and spectroscopic methods.

    PubMed

    Weyermann, Céline; Kirsch, Dieter; Vera, César Costa; Spengler, Bernhard

    2009-03-01

    Crystal violet is a very common dye in ballpoint ink. Recent research suggests that the degradation of triarylmethane dyes gives an indication of the age of a ballpoint pen entry on a document. The main problem for the quantitative evaluation of the degradation is that it is highly dependent on the exposure to light. Moreover additional factors, such as additives and substrate play an important role in this process. The aim of this work is to compare the degradation pathways of the pure dye in water and ethanol upon exposure to xenon light by UV/VIS spectrophotometry and laser desorption ionization. Significant differences have been observed in the products and the kinetics of the degradation. N-demethylation, an expected decomposition process, was found to take place only in aqueous solution and kinetics calculations showed that the degradation occurred 2.5 times faster in ethanol compared to water. The degradation of crystal violet in inks from four ballpoint pens on paper was also studied for entries made over 2-3 years. It was observed that degradation reactions were quenched by the presence of another dye due to competitive absorption. It was also observed that the thickness of a stroke (concentration of ink) influenced the degradation process. In the absence of light only one ballpoint pen showed slight degradation. A better understanding of the influence of the paper, ink composition, and storage conditions is necessary to interpret correctly the age of an ink based on the degradation of dyes. PMID:19220655

  20. Dichroism and birefringence of natural violet diamond crystals

    SciTech Connect

    Konstantinova, A. F. Titkov, S. V.; Imangazieva, K. B.; Evdishchenko, E. A.; Sergeev, A. M.; Zudin, N. G.; Orekhova, V. P.

    2006-05-15

    Investigation of the optical properties of natural violet diamonds from the Yakutian kimberlites is performed. A red shift of the absorption edge is revealed in the absorption spectra of these crystals. This shift is indicative of the presence of a high concentration of nitrogen in the diamonds studied. Along with the strong band at 0.550 {mu}m, weaker bands at 0.390, 0.456 and 0.496 {mu}m are revealed. It is shown that violet diamond crystals have birefringence and dichroism of about 10{sup -5} and 10{sup -6}, respectively. When a light beam propagates perpendicularly to colored lamellas, the dichroism is much larger and the birefringence is smaller than in the case where the beam direction is parallel to lamellas.

  1. Modeling of crystal violet adsorption by bottom ash column.

    PubMed

    Nidheesh, P V; Gandhimathi, R; Ramesh, S T; Singh, T S Anantha

    2013-06-01

    The removal of crystal violet from wastewater, by means of bottom ash, was investigated in a packed bed down-flow column. The bed depth service time (BDST) model was used to analyze the experimental data up to breakthrough time (corresponding to C(t)/C(0) = 0.1). A mass transfer model was used to analyze the mass transfer zone. The breakthrough curve was analyzed by the Thomas, Yoon-Nelson, and Clark models. All models fit well with the experimental data. Results showed that as the flow rate increases, at a constant concentration and bed depth, the value of the adsorption capacity of bottom ash decreases. The adsorption capacity of bottom ash decreases with an increase in depth and initial crystal violet concentration. Error analyses were performed for the Thomas, Yoon-Nelson, and Clark models. Water PMID:23833812

  2. Adsorption of Crystal violet on raw and acid-treated montmorillonite, K10, in aqueous suspension.

    PubMed

    Sarma, Gautam Kumar; Sen Gupta, Susmita; Bhattacharyya, Krishna G

    2016-04-15

    Crystal violet is used as a dye in cotton and silk textiles, paints and printing ink. The dye is hazardous and exposure to it may cause permanent injury to the cornea and conjunctiva including permanent blindness, and in severe cases, may lead to respiratory and kidney failure. The present work describes removal of Crystal violet from aqueous solution by adsorption on raw and acid-treated montmorillonite, K10. The clay mineral was treated with 0.25 and 0.50 M sulfuric acid and the resulting materials were characterized by XRD, zeta potential, SEM, FTIR, cation exchange capacity, BET surface area and pore volume measurements. The influences of pH, interaction time, adsorbent amount, and temperature on adsorption were monitored and explained on the basis of physico-chemical characteristics of the materials. Basic pH generally favors adsorption but considerable removal was possible even under neutral conditions. Adsorption was very rapid and equilibrium could be attained in 180 min. The kinetics conformed to second order model. Langmuir monolayer adsorption capacity of raw montmorillonite K10 was 370.37 mg g(-1) whereas 0.25 M and 0.50 M acid treated montmorillonite K10 had capacities of 384.62 and 400.0 mg g(-1) respectively at 303 K. Adsorption was exothermic and decreased in the temperature range of 293-323 K. Thermodynamically, the process was spontaneous with Gibbs energy decreasing with rise in temperature. The results suggest that montmorillonite K10 and its acid treated forms would be suitable for removing Crystal violet from aqueous solution. PMID:26866669

  3. Insight into biosorption equilibrium, kinetics and thermodynamics of crystal violet onto Ananas comosus (pineapple) leaf powder

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sagnik; Chowdhury, Shamik; Saha, Papita Das

    2012-06-01

    Biosorption performance of pineapple leaf powder (PLP) for removal of crystal violet (CV) from its aqueous solutions was investigated. To this end, the influence of operational parameters such as pH, biosorbent dose, initial dye concentration and temperature were studied employing a batch experimental setup. The biosorption process followed the Langmuir isotherm model with high correlation coefficients ( R 2 > 0.99) at different temperatures. The maximum monolayer biosorption capacity was found to be 78.22 mg g-1 at 293 K. The kinetic data conformed to the pseudo-second-order kinetic model. The activation energy of the system was calculated as 58.96 kJ mol- 1 , indicating chemisorption nature of the ongoing biosorption process. A thermodynamic study showed spontaneous and exothermic nature of the biosorption process. Owing to its low cost and high dye uptake capacity, PLP has potential for application as biosorbent for removal of CV from aqueous solutions.

  4. Post-column reaction for simultaneous analysis of chromatic and leuco forms of malachite green and crystal violet by high-performance liquid chromatography with photometric detection

    USGS Publications Warehouse

    Allen, J.L.; Meinertz, J.R.

    1991-01-01

    The chromatic and leuco forms of malachite green and crystal violet were readily separated and detected by a sensitive and selective high-performance liquid chromatographic procedure. The chromatic and leuco forms of the dyes were separated within 11 min on a C18 column with a mobile phase of 0.05 M sodium acetate and 0.05 M acetic acid in water (19%) and methanol (81%). A reaction chamber, containing 10% PbO2 in Celite 545, was placed between the column and the spectrophotometric detector to oxidize the leuco forms of the dyes to their chromatic forms. Chromatic and leuco malachite green were quantified by their absorbance at 618 nm; and chromatic and leuco Crystal Violet by their absorbance at 588 nm. Detection limits for chromatic and leuco forms of both dyes ranged from 0.12 to 0.28 ng. A linear range of 1 to 100 ng was established for both forms of the dyes.

  5. BIODEGRADATION OF CRYSTAL VIOLET BY THE WHITE ROT FUNGUS PHANEROCHAETE CHRYSOPORIUM

    EPA Science Inventory

    Biodegradation of crystal violet (N,N,N',N',N",N"-hexamethylpararosaniline) in ligninolytic (nitrogen-limited) cultures of the white rot fungus Phanerochaete chrysosporium was demonstrated by the disappearance of crystal violet and by the identification of three metabolites (N,N,...

  6. Bordetella bronchiseptica phase variation induced by crystal violet.

    PubMed Central

    Ishikawa, H; Isayama, Y

    1986-01-01

    A method for effective induction of phase variation in Bordetella bronchiseptica by treatment with crystal violet (CV) is presented. When grown in CV-broth, phase I cells dissociated into three serial phases. Appearance of variant cells was observed simultaneously with the beginning of cell multiplication. The maximum effect of CV was obtained at a concentration of 8 micrograms/ml, when the proportion of variants in the population reached 100%. The main factors which affected phase variation were concentration of CV, culture age, and temperature of treatment. The phase variants obtained were phenotypically stable upon serial passages on Bordet-Gengou agar plates. By this treatment, no reversion of phase descendants to former phases was observed. Images PMID:3700613

  7. Adsorption of crystal violet with diatomite earth&carbon by a modification of hydrothermal carbonization process.

    PubMed

    Zhang, Yanzhuo; Li, Jun; Chen, Guanghui; Bian, Wei; Lu, Yun; Li, Wenjing; Zheng, Zhaoming; Cheng, Xiaojie

    2016-01-01

    The high colority and difficulty of decolorization are the most important tasks on printing and dyeing wastewater. This study investigates the ability of diatomite earth&carbon (DE&C) as an adsorbent to removal crystal violet (CV) from aqueous solutions. Fourier transform infrared spectroscopy results indicate the importance of functional groups during the adsorption of CV. The obtained N2 adsorption-desorption isotherm values accord with well IUPAC type II. Our calculations determined a surface area of 73.15 m(2) g(-1) for DE&C and an average pore diameter of 10.56 nm. Equilibrium data of the adsorption process fitted very well to the Langmuir model (R(2) > 0.99). The results of kinetics study showed that the pseudo-second-order model fitted to the experimental data well. The thermodynamic parameters were also evaluated. ΔH° <0, ΔS° > 0 and ΔG° < 0 demonstrated that the adsorption process was spontaneous and exothermic for dye. Furthermore the positive value of ΔS° reflected good affinity of the CV dye. PMID:27003089

  8. Exposure to Crystal Violet, Its Toxic, Genotoxic and Carcinogenic Effects on Environment and Its Degradation and Detoxification for Environmental Safety.

    PubMed

    Mani, Sujata; Bharagava, Ram Naresh

    2016-01-01

    Crystal Violet (CV), a triphenylmethane dye, has been extensively used in human and veterinary medicine as a biological stain, as a textile dye in textile processing industries and also used to provide a deep violet color to paints and printing ink. CV is also used as a mutagenic and bacteriostatic agent in medical solutions and antimicrobial agent to prevent the fungal growth in poultry feed. Inspite of its many uses, CV has been reported as a recalcitrant dye molecule that persists in environment for a long period and pose toxic effects in environment. It acts as a mitotic poison, potent carcinogen and a potent clastogene promoting tumor growth in some species of fish. Thus, CV is regarded as a biohazard substance. Although, there are several physico-chemical methods such as adsorption, coagulation and ion-pair extraction reported for the removal of CV, but these methods are insufficient for the complete removal of CV from industrial wastewaters and also produce large quantity of sludge containing secondary pollutants. However, biological methods are regarded as cost-effective and eco-friendly for the treatment of industrial wastewaters, but these methods also have certain limitations. Therefore, there is an urgent need to develop such eco-friendly and cost-effective biological treatment methods, which can effectively remove the dye from industrial wastewaters for the safety of environment, as well as human and animal health. PMID:26613989

  9. UV-vis, IR and 1H NMR spectroscopic studies and characterization of ionic-pair crystal violet-oxytetracycline

    NASA Astrophysics Data System (ADS)

    Orellana, Sandra; Soto, César; Toral, M. Inés

    2010-01-01

    The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0 ± 0.2 extracted into chloroform. The characterization was demonstrated using UV-vis spectrophotometry, 1H NMR, measurement of relaxation times T1 and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV-OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic.

  10. Crystal Violet Lactone Salicylaldehyde Hydrazone Zn(II) Complex: a Reversible Photochromic Material both in Solution and in Solid Matrix

    PubMed Central

    Li, Kai; Li, Yuanyuan; Tao, Jing; Liu, Lu; Wang, Lili; Hou, Hongwei; Tong, Aijun

    2015-01-01

    Crystal violet lactone (CVL) is a classic halochromic dye which has been widely used as chromogenic reagent in thermochromic and piezochromic systems. In this work, a very first example of CVL-based reversible photochromic compound was developed, which showed distinct color change upon UV-visible light irradiation both in solution and in solid matrix. Moreover, metal complex of CVL salicylaldehyde hydrozone was facilely synthesized, exhibiting reversible photochromic properties with good fatigue resistance. It was served as promising solid material for photo-patterning. PMID:26412101

  11. Crystal Violet Lactone Salicylaldehyde Hydrazone Zn(II) Complex: a Reversible Photochromic Material both in Solution and in Solid Matrix.

    PubMed

    Li, Kai; Li, Yuanyuan; Tao, Jing; Liu, Lu; Wang, Lili; Hou, Hongwei; Tong, Aijun

    2015-01-01

    Crystal violet lactone (CVL) is a classic halochromic dye which has been widely used as chromogenic reagent in thermochromic and piezochromic systems. In this work, a very first example of CVL-based reversible photochromic compound was developed, which showed distinct color change upon UV-visible light irradiation both in solution and in solid matrix. Moreover, metal complex of CVL salicylaldehyde hydrozone was facilely synthesized, exhibiting reversible photochromic properties with good fatigue resistance. It was served as promising solid material for photo-patterning. PMID:26412101

  12. Crystal Violet Lactone Salicylaldehyde Hydrazone Zn(II) Complex: a Reversible Photochromic Material both in Solution and in Solid Matrix

    NASA Astrophysics Data System (ADS)

    Li, Kai; Li, Yuanyuan; Tao, Jing; Liu, Lu; Wang, Lili; Hou, Hongwei; Tong, Aijun

    2015-09-01

    Crystal violet lactone (CVL) is a classic halochromic dye which has been widely used as chromogenic reagent in thermochromic and piezochromic systems. In this work, a very first example of CVL-based reversible photochromic compound was developed, which showed distinct color change upon UV-visible light irradiation both in solution and in solid matrix. Moreover, metal complex of CVL salicylaldehyde hydrozone was facilely synthesized, exhibiting reversible photochromic properties with good fatigue resistance. It was served as promising solid material for photo-patterning.

  13. Crystal Violet and XTT Assays on Staphylococcus aureus Biofilm Quantification.

    PubMed

    Xu, Zhenbo; Liang, Yanrui; Lin, Shiqi; Chen, Dingqiang; Li, Bing; Li, Lin; Deng, Yang

    2016-10-01

    Staphylococcus aureus (S. Aureus) is a common food-borne pathogenic microorganism. Biofilm formation remains the major obstruction for bacterial elimination. The study aims at providing a basis for determining S. aureus biofilm formation. 257 clinical samples of S. aureus isolates were identified by routine analysis and multiplex PCR detection and found to contain 227 MRSA, 16 MSSA, 11 MRCNS, and 3 MSCNS strains. Two assays for quantification of S. aureus biofilm formation, the crystal violet (CV) assay and the XTT (tetrazolium salt reduction) assay, were optimized, evaluated, and further compared. In CV assay, most isolates formed weak biofilm 74.3 %), while the rest formed moderate biofilm (23.3 %) or strong biofilm (2.3 %). However, most isolates in XTT assay showed weak metabolic activity (77.0 %), while the rest showed moderate metabolic activity (17.9 %) or high metabolic activity (5.1 %). In this study, we found a distinct strain-to-strain dissimilarity in terms of both biomass formation and metabolic activity, and it was concluded from this study that two assays were mutual complementation rather than being comparison. PMID:27324342

  14. Synthesis of CarAlg/MMt nanocomposite hydrogels and adsorption of cationic crystal violet.

    PubMed

    Mahdavinia, Gholam Reza; Aghaie, Huriyeh; Sheykhloie, Hossein; Vardini, Mohammad Taghi; Etemadi, Hossein

    2013-10-15

    CarAlg/MMt nanocomposite hydrogels composed of kappa-carrageenan (Car) and sodium alginate (Alg) biopolymers were synthesized by incorporation of sodium montmorillonite (Na-MMt) nanoclay. Acrylamide (AAm), methylenebisacrylamide (MBA), and ammonium persulfate (APS) were used as monomer, crosslinker, and initiator, respectively. The structure and morphology of nanocomposites were characterized by XRD, SEM, and TEM techniques. The XRD results showed exfoliated MMt nanoclay and exfoliation of MMt was confirmed by TEM graph. The resulting nanocomposites were evaluated to remove cationic crystal violet (CV) dye from water. According to data, the adsorption capacity of nanocomposites was enhanced as the clay content was increased. The experimental data were analyzed according to both Langmuir and Freundlich models and experimental maximum adsorption capacity was obtained 88.8 mg g(-1). By studying the effect of pH on the dye adsorption capacity of nanocomposites, it was revealed that the adsorption capacity of nanocomposites was enhanced at acidic pHs as the Na-MMt nanoclay and kappa-carrageenan components were increased. PMID:23987355

  15. New Treatment for Infection of the NIPRO LVAD Cannula Site: Nihon University Crystal Violet Method.

    PubMed

    Sezai, Akira; Niino, Tetsuya; Osaka, Shunji; Yaoita, Hiroko; Arimoto, Munehito; Hata, Hiroaki; Shiono, Motomi

    2016-01-01

    Driveline and cannula site infections are still a frequent adverse event in patients with a ventricular assist device (VAD), and it is important to treat and prevent them because the spread of local infection may cause sepsis in some cases. We report our experience with a patient in whom infection of the NIPRO LVAD cannula site after implantation of an extracorporeal VAD was controlled by treatment with crystal violet Solbase (Nihon University crystal violet method). PMID:26694275

  16. White Light-Activated Antimicrobial Paint using Crystal Violet.

    PubMed

    Hwang, Gi Byoung; Allan, Elaine; Parkin, Ivan P

    2016-06-22

    Crystal violet (CV) was incorporated into acrylic latex to produce white-light-activated antimicrobial paint (WLAAP). Measurement of the water contact angle of the WLAAP showed that the water contact angle increased with increasing CV concentration. In a leaching test over 120 h, the amount of CV that leached from the WLAAPs was close to the detection limit (<0.03%). The WLAAPs were used to coat samples of polyurethane, and these showed bactericidal activity against Escherichia coli, which is a key causative agent of healthcare-associated infections (HAIs). A reduction in the numbers of viable bacteria was observed on the painted coated polyurethane after 6 h in the dark, and the bactericidal activity increased with increasing CV concentration (P < 0.1). After 6 h of white light exposure, all of coated polyurethanes demonstrated a potent photobactericidal activity, and it was statistically confirmed that the WLAAP showed better activity in white light than in the dark (P < 0.05). At the highest CV concentration, the numbers of viable bacteria fell below the detection limit (<10(3) CFU/mL) after 6 h of white light exposure. The difference in antimicrobial activity between the materials in the light and dark was 0.48 log at CV 250 ppm, and it increased by 0.43 log at each increment of CV 250 ppm. The difference was the highest (>1.8 log) at the highest CV concentration (1000 ppm). These WLAAPs are promising candidates for use in healthcare facilities to reduce HAIs. PMID:26479680

  17. Fixed-bed column studies on biosorption of crystal violet from aqueous solution by Citrullus lanatus rind and Cyperus rotundus

    NASA Astrophysics Data System (ADS)

    Bharathi, Kandaswamy Suyamboo; Ramesh, SriKrishna Perumal Thanga

    2013-12-01

    In this study, fixed-bed column experiments were performed to investigate the biosorption potential of two agricultural wastes, Citrullus lanatus rind and Cyperus rotundus to remove Crystal violet (CV) from aqueous solution. The experiments were conducted to study the effects of important parameters such as bed depth (10-30 cm), flow rate (10-20 mL min-1) and initial dye concentration (10-25 mg L-1). Different models like Bed Depth Service Time (BDST) model, Thomas model and Yoon-Nelson model were applied to the experimental sorption data. In the biosorption of Crystal violet by both the sorbents, the BDST model fitted well with the experimental data in the initial region of the breakthrough curve. Also, Yoon-Nelson model was found to show good agreement with the experimental kinetic results as compared to the Thomas model. The sorbents were found to be very potential, as it showed good sorption capacities of 46.68 and 54.24 mg g-1 for CV biosorption by Citrullus lanatus rind and Cyperus rotundus. Recovery of dye was made by eluting 1 N CH3COOH through the exhausted column in downward direction.

  18. Removal of crystal violet from water by magnetically modified activated carbon and nanomagnetic iron oxide.

    PubMed

    Hamidzadeh, Soheila; Torabbeigi, Marzieh; Shahtaheri, Seyed Jamaleddin

    2015-01-01

    Magnetically modified activated carbon, which synthesized by nanomagnetic iron oxide, was used for fast and effective removal of Crystal Violet from aqueous solutions. The scanning electron microscopy (SEM) images of nano-adsorbent showed that the average sizes of adsorbent are less than 100 nm. The various parameters, affecting on adsorption process, were examined including pH and temperature of dye solution, dose of adsorbent, and contact time. Then, thermodynamic parameters of sorption were calculated. Langmuir and Freundlich isotherms were used to fit the resulting data. Adsorption kinetics was consistent with a pseudo second order equation. Thermodynamic parameters of adsorption, ∆H(0), and ∆S(0) were calculated. Also, for further investigations, nano magnetic iron oxides was synthesized and used as adsorbent. Sorption capacities were depending on the temperature varied from 44.7 to 67.1 mg/g and from 12.7 to 16.5 mg/g for magnetically modified activated carbon and nanomagnetic iron oxide, respectively. PMID:25699186

  19. The MTT and Crystal Violet Assays: Potential Confounders in Nanoparticle Toxicity Testing.

    PubMed

    Almutary, A; Sanderson, B J S

    2016-07-01

    The toxicological effects of nanoparticles (NPs) on humans, animals, and environment are largely unknown. Assessment of NPs cytotoxicity depends on the choice of the test system. Due to NPs optical activity and absorption values, they can influence the classical cytotoxicity assay. Eight NPs were spiked in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays and tested with HaCaT human skin cells. The MTT assay standard curve optical density (OD) measurements were altered by the presence of trisilanol phenyl and trisilanol isooctyl polyhedral oligomeric silsesquioxane particles. The crystal violet standard curve OD measurements were significantly shifted by gold NPs, but they did not affect the MTT assay. Carbon black decreased ODs in the MTT and crystal violet assays and was localized in the cell cytoplasm. These findings strongly indicate that a careful choice of in vitro viability systems is required to avoid flawed measurement of NPs toxicity. PMID:27207930

  20. Biocompatibility of the vital dye Acid Violet-17 on retinal pigment epithelial cells

    PubMed Central

    Tura, Ayşegül; Alt, Aizhan; Lüke, Julia; Grisanti, Salvatore; Haritoglou, Christos; Meyer, Carsten H; Nassar, Khaled; Lüke, Matthias

    2016-01-01

    Purpose To examine the viability and differentiation of retinal pigment epithelial (RPE) cells after exposure to the vital dye Acid Violet-17 (AV-17). Methods Bovine RPE cells were incubated with AV-17 (0.0625–0.5 mg/mL) for 30 seconds or 5 minutes. Viability was determined by live/dead staining, cleaved CASP3 immunostainings, and MTT test. Actin cytoskeleton was visualized by Alexa 488-phalloidin. Immunocytochemistry was performed to determine the levels of ZO-1, CTNNB1, and KRT19. Results Exposure to AV-17 at the concentrations of 0.25–0.5 mg/mL resulted in a dose-dependent decrease in viability, the loss of ZO-1 from tight junctions, translocation of CTNNB1 into the cytoplasm and nucleus, disarrangement of the actin cytoskeleton, and a slight increase in KRT19. Conclusion AV-17 at a concentration <0.125 mg/mL is likely to be well tolerated by the RPE cells, whereas the concentrations from 0.25 mg/mL onward can reduce viability and induce dedifferentiation particularly after long-term exposure. PMID:27536056

  1. Spectroscopic investigation of alloyed quantum dot-based FRET to cresyl violet dye.

    PubMed

    Kotresh, M G; Adarsh, K S; Shivkumar, M A; Mulimani, B G; Savadatti, M I; Inamdar, S R

    2016-05-01

    Quantum dots (QDs), bright luminescent semiconductor nanoparticles, have found numerous applications ranging from optoelectronics to bioimaging. Here, we present a systematic investigation of fluorescence resonance energy transfer (FRET) from hydrophilic ternary alloyed quantum dots (CdSeS/ZnS) to cresyl violet dye with a view to explore the effect of composition of QD donors on FRET efficiency. Fluorescence emission of QD is controlled by varying the composition of QD without altering the particle size. The results show that quantum yield of the QDs increases with increase in the emission wavelength. The FRET parameters such as spectral overlap J(λ), Förster distance R0 , intermolecular distance (r) , rate of energy transfer kT (r), and transfer efficiency (E) are determined by employing both steady-state and time-resolved fluorescence spectroscopy. Additionally, dynamic quenching is noticed to occur in the present FRET system. Stern-Volmer (KD ) and bimolecular quenching constants (kq ) are determined from the Stern-Volmer plot. It is observed that the transfer efficiency follows a linear dependence on the spectral overlap and the quantum yield of the donor as predicted by the Förster theory upon changing the composition of the QD. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26333828

  2. [Active carbon from Thalia dealbata residues: its preparation and adsorption performance to crystal violet].

    PubMed

    Chu, Shu-Yi; Yang, Min; Xiao, Ji-Bo; Zhang, Jun; Zhu, Yan-Ping; Yan, Xiang-Jun; Tian, Guang-Ming

    2013-06-01

    By using phosphoric acid as activation agent, active carbon was prepared from Thalia dealbata residues. The BET specific surface area of the active carbon was 1174.13 m2 x g(-1), micropore area was 426.99 m2 x g(-1), and average pore diameter was 3.23 nm. An investigation was made on the adsorption performances of the active carbon for crystal violet from aqueous solution under various conditions of pH, initial concentration of crystal violet, contact time, and contact temperature. It was shown that the adsorbed amount of crystal violet was less affected by solution pH, and the adsorption process could be divided into two stages, i. e., fast adsorption and slow adsorption, which followed the pseudo-second-order kinetics model. At the temperature 293, 303, and 313 K, the adsorption process was more accordance with Langmuir isotherm model, and the maximum adsorption capacity was 409.83, 425.53, and 438.59 mg x g(-1), respectively. In addition, the adsorption process was spontaneous and endothermic, and the randomness of crystal violet molecules increased. PMID:24066559

  3. Quantitative super-resolution localization microscopy of DNA in situ using Vybrant® DyeCycle™ Violet fluorescent probe.

    PubMed

    Żurek-Biesiada, Dominika; Szczurek, Aleksander T; Prakash, Kirti; Best, Gerrit; Mohana, Giriram K; Lee, Hyun-Keun; Roignant, Jean-Yves; Dobrucki, Jurek W; Cremer, Christoph; Birk, Udo

    2016-06-01

    Single Molecule Localization Microscopy (SMLM) is a recently emerged optical imaging method that was shown to achieve a resolution in the order of tens of nanometers in intact cells. Novel high resolution imaging methods might be crucial for understanding of how the chromatin, a complex of DNA and proteins, is arranged in the eukaryotic cell nucleus. Such an approach utilizing switching of a fluorescent, DNA-binding dye Vybrant® DyeCycle™ Violet has been previously demonstrated by us (Żurek-Biesiada et al., 2015) [1]. Here we provide quantitative information on the influence of the chemical environment on the behavior of the dye, discuss the variability in the DNA-associated signal density, and demonstrate direct proof of enhanced structural resolution. Furthermore, we compare different visualization approaches. Finally, we describe various opportunities of multicolor DNA/SMLM imaging in eukaryotic cell nuclei. PMID:27054149

  4. Quantitative super-resolution localization microscopy of DNA in situ using Vybrant® DyeCycle™ Violet fluorescent probe

    PubMed Central

    Żurek-Biesiada, Dominika; Szczurek, Aleksander T.; Prakash, Kirti; Best, Gerrit; Mohana, Giriram K.; Lee, Hyun-Keun; Roignant, Jean-Yves; Dobrucki, Jurek W.; Cremer, Christoph; Birk, Udo

    2016-01-01

    Single Molecule Localization Microscopy (SMLM) is a recently emerged optical imaging method that was shown to achieve a resolution in the order of tens of nanometers in intact cells. Novel high resolution imaging methods might be crucial for understanding of how the chromatin, a complex of DNA and proteins, is arranged in the eukaryotic cell nucleus. Such an approach utilizing switching of a fluorescent, DNA-binding dye Vybrant® DyeCycle™ Violet has been previously demonstrated by us (Żurek-Biesiada et al., 2015) [1]. Here we provide quantitative information on the influence of the chemical environment on the behavior of the dye, discuss the variability in the DNA-associated signal density, and demonstrate direct proof of enhanced structural resolution. Furthermore, we compare different visualization approaches. Finally, we describe various opportunities of multicolor DNA/SMLM imaging in eukaryotic cell nuclei. PMID:27054149

  5. Clinical usefulness of intradermal fluorescein and patent blue violet dyes for sentinel lymph node identification in dogs.

    PubMed

    Wells, S; Bennett, A; Walsh, P; Owens, S; Peauroi, J

    2006-06-01

    The first lymph node receiving drainage from a specific anatomic region is referred to as the sentinel lymph node (SLN). This study sought to evaluate the intradermal use of two dyes, patent blue violet (PBV) and fluorescein (FL), for SLN mapping in the dog. Multiple intradermal injections were performed in five healthy dogs using two dyes, PBV in 0.9% NaCl and FL in solutions of 0.9% NaCl and 6% hetastarch. Skin flaps were raised and followed to the first area of discrete stain uptake. Areas of uptake were identified as lymph nodes grossly and by cytology. Identification of a SLN for each area of intradermal injection was accomplished for 98% of the injection sites. Intradermal injections of both PBV and FL dyes produce readily visible staining of lymphatic vessels and SLNs in healthy dogs and are sufficient to allow ready identification of these structures during postmortem dissection. PMID:19754821

  6. Ion pairs of crystal violet in sodium bis(2-ethylhexyl)sulfosuccinate reverse micelles.

    PubMed

    Oliveira, Carla S; Bastos, Erick L; Duarte, Evandro L; Itri, Rosangela; Baptista, Mauricio S

    2006-10-10

    The interfacial localization and the ion pair formation of the positively charged dye crystal violet (CV) in sodium bis(2-ethylhexyl)sulfosuccinate reverse micelles (AOT RMs) were studied by several structural and spectroscopic techniques and by quantum chemical calculations. The size and shape of the AOT RMs in the presence of CV were investigated by small-angle X-ray scattering, showing that CV does not significantly change the RM structure. CV localization as a function of the water to surfactant molar ratio (w(0)) was characterized by H(1) and (13)C NMR, indicating the close proximity of CV to the sulfosuccinate group of AOT at small and large w(0) values. These results were confirmed by calculation of magnetic shielding constants using the gauge-independent atomic orbital method with the HF/6-31G(d) basis set. Two different types of ion pairs between AOT and CV, i.e., contact ion pair (CIPs) and solvent-separated ion pair (SSIPs), were characterized by UV-vis spectroscopy and quantum chemical calculations using the semiempirical ZINDO-CI method. In nonpolar isotropic solvents CIPs are formed with an association constant (K(ASSOC)) of 2 x 10(4) mol(-1) L in isooctane and 750 mol(-1) L in chloroform. In AOT RMs at low w(0), CV-AOT CIPs are also formed. By increasing w(0), there is a sharp decrease in the CIP association free energy, and SSIPs are formed. (CV(+))(H(2)O)(AOT(-)) SSIPs are stable in the AOT RM up to the largest w(0) tested (w(0) = 33). PMID:17014109

  7. Biodegradation of crystal violet using Burkholderia vietnamiensis C09V immobilized on PVA-sodium alginate-kaolin gel beads.

    PubMed

    Cheng, Ying; Lin, HongYan; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

    2012-09-01

    The strain, Burkholderia vietnamiensis C09V was immobilized on PVA-alginate-kaolin gel beads as a biomaterial to improve the degradation of crystal violet from aqueous solution. The results show that 98.6% (30 mg L(-1)) crystal violet was removed from aqueous solution using immobilized cells on PVA-alginate-kaolin gel beads, while 94.0% crystal violet was removed by free cells after degradation at the pH 5 and 30°C for 30 h. Kinetics studies show that the pseudo-second-order kinetics well described the adsorption of crystal violet on the PVA-alginate-kaolin beads. Biodegradation of crystal violet on immobilized cells was fitted well by first-order reaction kinetics, indicating that CV was adsorbed onto kaolin and followed their degradation by immobilized cells onto the the PVA-alginate-kaolin beads. Characterization with SEM shows that cells attached well to the surface of PVA-alginate-kaolin beads, leading to improved crystal violet transfer from aqueous solution to immobilized cells. In addition, UV-vis show that the absorption peak at 588 nm was reduced by the degraded N-bond linkages, as well as the formation of degrading products were observed by Fourier transform infrared (FTIR). These results suggest that crystal violet was biodegraded to N,N-dimethylaminophenol and Michler's Ketone prior to these intermediates being further degraded. PMID:22789742

  8. Low-cost nanoparticles sorbent from modified rice husk and a copolymer for efficient removal of Pb(II) and crystal violet from water.

    PubMed

    Masoumi, Arameh; Hemmati, Khadijeh; Ghaemy, Mousa

    2016-03-01

    In this work, preparation of adsorbent nanoparticles based on treated low-value agricultural by-product rice husk (TARH), and poly(methylmethacrylate-co-maleic anhydride), poly(MMA-co-MA), is reported for the removal of Pb(II) ion and Crystal violet dye from water. The prepared adsorbent was characterized by FT-IR, SEM, AFM, DLS, BET and Zeta potential. The metal ion adsorption capability was determined for rice husk (RH), TARH, crosslinked poly(MMA-co-MA) (CNR), and CNR@TARH nanoparticles. Different factors affecting the adsorption of Pb(II) such as pH, contact time, initial metal ion concentration and also temperature were studied to investigate adsorption isotherms, kinetics and thermodynamics. For the four tested adsorption isotherm models, the equilibrium sorption data for CNR@TARH nanoparticles obeyed the Langmuir isotherm equation with maximum sorption capacity of 93.45 mg g(-1). The kinetic adsorption data fitted best the Lagergren pseudo-second order model. Regeneration of adsorbent was easily performed by adsorption/desorption experiments followed for 4 cycles. Finally, the ability of the nanoparticles to remove Crystal violet dye from aqueous solution was also investigated by varying the initial dye concentration, pH and immersion time and the adsorption mechanism followed the second-order kinetic model. PMID:26735725

  9. Fish erythrocytes as biomarkers for the toxicity of sublethal doses of an azo dye, Basic Violet-1 (CI: 42535).

    PubMed

    Kaur, Kirandeep; Kaur, Arvinder

    2015-02-01

    The aim of the present study was to investigate poikilocytosis in Labeo rohita (an important food fish) as an early indicator of stress due to an azo dye, Basic Violet-1 (CI: 42535). This dye was observed to be very toxic to test fish (96 h LC50 as0.45 mg/L dye). Fish were given short-term (96 h) and subchronic (150 days) exposures to the dye, and poikilocytosis was recorded under light and scanning electron microscopy (SEM). Light microscopy helped in identification of micronuclei along with irregularities, notches, blebs, lobes, crenation, clumps, chains, spherocytes, vacuolation, and necrosis in erythrocytes. However, SEM indicated shrinkage, oozing of cytoplasm, and several new abnormal shapes including marginal foldings, discocytes, keratocytes, dacrocytes, degmacytes, acanthocytes, echinocytes, protuberances, stomatocytes, drepanocytes, holes in the membrane, stippling/spicules, crescent-shaped cells, triangular cells, and pentagonal cells. Earlier studies speculated changes in the membrane to be responsible for clumping and chaining of erythrocytes, whereas the present SEM study clearly indicates that oozing out of cytoplasm is also responsible for the formation of chains and clumps. This study also shows that erythrocytes exhibit pathological symptoms before the appearance of other external symptoms such as abnormal behavior or mortality of fish. There was a dose- and duration-dependent increase; therefore, poikilocytosis, especially echinocytes, spherocytes, and clumps, can act as a biomarker for the stress caused by azo dyes. PMID:25434363

  10. Modification of the photocatalytic activity of TiO2 by β-Cyclodextrin in decoloration of ethyl violet dye

    PubMed Central

    Velusamy, Ponnusamy; Pitchaimuthu, Sakthivel; Rajalakshmi, Subramanian; Kannan, Nagarathinam

    2012-01-01

    The photocatalytic decoloration of an organic dye, ethyl violet (EV), has been studied in the presence of TiO2 and the addition of β-Cyclodextrin (β-CD) with TiO2 (TiO2-β-CD) under UV-A light irradiation. The different operating parameters like initial concentration of dye, illumination time, pH and amount of catalyst used have also been investigated. The photocatalytic decoloration efficiency is more in the TiO2-β-CD/UV-A light system than TiO2/UV-A light system. The mineralization of EV has been confirmed by Chemical Oxygen Demand (COD) measurements. The complexation patterns have been confirmed with UV–Visible and FT-IR spectral data and the interaction between TiO2 and β-CD have been characterized by powder XRD analysis and UV–Visible diffuse reflectance spectroscopy. PMID:25685468

  11. Surface-enhanced Raman scattering of crystal violets from periodic array of gold nanocylinders

    NASA Astrophysics Data System (ADS)

    Bi, Gang; Wang, Li; Cai, Chunfeng; Ueno, Kosei; Misawa, Hiroaki; Qiu, Jianrong

    2014-09-01

    The periodic arrays of gold nanocylinder with 121 nm in diameter, 6.3 nm in gap, and 34 nm in thickness are fabricated on glass by electron-beam lithography and lift-off techniques. Some crystal violet molecules are coated on the array by using the dipping and drawing method. In addition, the surface-enhanced Raman scattering (SERS) spectra of these samples with and without gold nanocylinder arrays are characterized specifically. The largest enhancement factor is obtained when the excitation wavelength corresponds to the peak wavelength of localized surface plasmon resonance (LSPR). The density functional theory and the finite-difference time-domain method are used for the calculations of the extinction spectrum of the arrays and Raman spectra of the crystal violet, respectively. These results unambiguously demonstrate that the periodic arrays of gold nanocylinder have good and effective surface-enhanced properties for Raman scattering of crystal violets, and they also show that the excitation wavelength corresponding to the peak one of the LSPR is one of the major reasons causing SERS.

  12. Sensitive detection of malachite green and crystal violet by nonlinear laser wave mixing and capillary electrophoresis.

    PubMed

    Maxwell, Eric J; Tong, William G

    2016-05-01

    An ultrasensitive label-free antibody-free detection method for malachite green and crystal violet is presented using nonlinear laser wave-mixing spectroscopy and capillary zone electrophoresis. Wave-mixing spectroscopy provides a sensitive absorption-based detection method for trace analytes. This is accomplished by forming dynamic gratings within a sample cell, which diffracts light to create a coherent laser-like signal beam with high optical efficiency and high signal-to-noise ratio. A cubic dependence on laser power and square dependence on analyte concentration make wave mixing sensitive enough to detect molecules in their native form without the use of fluorescent labels for signal enhancement. A 532 nm laser and a 635 nm laser were used for malachite green and crystal violet sample excitation. The use of two lasers of different wavelengths allows the method to simultaneously detect both analytes. Selectivity is obtained through the capillary zone electrophoresis separation, which results in characteristic migration times. Measurement in capillary zone electrophoresis resulted in a limit of detection of 6.9 × 10(-10)M (2.5 × 10(-19) mol) for crystal violet and 8.3 × 10(-11)M (3.0 × 10(-20) mol) for malachite green at S/N of 2. PMID:26998858

  13. Electrochemical degradation of crystal violet with BDD electrodes: effect of electrochemical parameters and identification of organic by-products.

    PubMed

    Palma-Goyes, Ricardo E; Guzmán-Duque, Fernando L; Peñuela, Gustavo; González, Ignacio; Nava, Jose L; Torres-Palma, Ricardo A

    2010-09-01

    This paper explores the applicability of electrochemical oxidation on a triphenylmethane dye compound model, hexamethylpararosaniline chloride (or crystal violet, CV), using BDD anodes. The effect of the important electrochemical parameters: current density (2.5-15 m A cm(-2)), dye concentration (33-600 mg L(-1)), sodium sulphate concentration (7.1-50.0 g L(-1)) and initial pH (3-11) on the efficiency of the electrochemical process was evaluated. The results indicated that while the current density was lower than the limiting current density, no side products (hydrogen peroxide, peroxodisulphate, ozone and chlorinated oxidizing compounds) were generated and the degradation, through OH radical attack, occurred with high efficiency. Analysis of intermediates using GC-MS investigation identified several products: N-methylaniline, N,N-dimethylaniline, 4-methyl-N,N-dimethylaniline, 4-methyl-N-methylaniline, 4-dimethylaminophenol, 4-dimethylaminobenzoic acid, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino) diphenylmethane, 4-(4-dimethylaminophenyl)-N,N-dimethylaniline, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino) benzophenone. The presence of these aromatic structures showed that the main CV degradation pathway is related to the reaction of CV with the OH radical. Under optimal conditions, practically 100% of the initial substrate and COD were eliminated in approximately 35 min of electrolysis; indicating that the early CV by-products were completely degraded by the electrochemical system. PMID:20709357

  14. Investigating the interaction of crystal violet probe molecules on sodium dodecyl sulfate micelles with hyper-Rayleigh scattering.

    PubMed

    Revillod, Guillaume; Russier-Antoine, Isabelle; Benichou, Emmanuel; Jonin, Christian; Brevet, Pierre-François

    2005-03-24

    We report the use of the nonlinear optical technique of hyper-Rayleigh scattering to investigate the interaction of the cationic probe molecule crystal violet with micelles of sodium dodecyl sulfate. An absolute value of (847 +/- 80) x 10(-30) esu is measured at the fundamental wavelength of 870 nm for the molecular hyperpolarizability of crystal violet free in pure aqueous solutions. In aqueous solutions of sodium dodecyl sulfate, above and below the critical micelle concentration, the measured hyperpolarizability of crystal violet is weaker than in the solution free of sodium dodecyl sulfate. From the comparison with linear optical photoabsorption spectroscopy data, this difference is attributed to electrostatic interactions between the cationic crystal violet molecules and the negatively charged sodium dodecyl sulfate surfactant molecules present in excess. Polarization resolved hyper-Rayleigh scattering measurements are then performed to show that, below and above the critical micelle concentration, crystal violet molecules also undergo symmetry changes upon interaction with sodium dodecyl sulfate. Above the critical micelle concentration, the minimum fraction of micelles interacting with at least one CV molecule is estimated. For instance, for a crystal violet aqueous concentration of 150 microM, this fraction is larger than 7%. PMID:16863205

  15. Effectiveness of photochemical and sonochemical processes in degradation of Basic Violet 16 (BV16) dye from aqueous solutions

    PubMed Central

    2012-01-01

    In this study, degradation of Basic Violet 16 (BV16) by ultraviolet radiation (UV), ultrasonic irradiation (US), UV/H2O2 and US/H2O2 processes was investigated in a laboratory-scale batch photoreactor equipped with a 55W immersed-type low-pressure mercury vapor lamp and a sonoreactor with high frequency (130kHz) plate type transducer at 100W of acoustic power. The effects of initial dye concentration, concentration of H2O2 and solution pH and presence of Na2SO4 was studied on the sonochemical and photochemical destruction of BV16 in aqueous phase. The results indicated that in the UV/H2O2 and US/H2O2 systems, a sufficient amount of H2O2 was necessary, but a very high H2O2 concentration would inhibit the reaction rate. The optimum H2O2 concentration was achieved in the range of 17 mmol/L at dye concentration of 30 mg/L. A degradation of 99% was obtained with UV/H2O2 within 8 minutes while decolorization efficiency by using UV (23%), US (<6%) and US/H2O2(<15%) processes were negligible for this kind of dye. Pseudo-first order kinetics with respect to dyestuffs concentrations was found to fit all the experimental data. PMID:23369268

  16. Removal of Alizarin Violet 3R (anthraquinonic dye) from aqueous solutions by natural coagulants.

    PubMed

    Beltrán-Heredia, J; Sánchez-Martín, J; Delgado-Regalado, A; Jurado-Bustos, C

    2009-10-15

    In this paper the ability of two natural products in removing dyes has been tested. After a preliminary screening for dye removal capacity, a tannin-based coagulant called ACQUAPOL C-1 and a vegetal protein extract derived from Moringa oleifera seed have been fully studied. The influence of several parameters such as pH, temperature or initial dye concentration (IDC) have been tested and the behavior of both coagulants has been compared. pH results to be an interesting variable and dye removal decreases as pH increases. This effect is higher in ACQUAPOL C-1 than in M. oleifera seed extract. Temperature seems not to be so affecting parameter, while IDC appears to be a very important variable in q(c) capacity, which is higher as IDC increases. Langmuir isotherm model fits very well in both cases of ACQUAPOL C-1 and M. oleifera seed extract dye removal. PMID:19481341

  17. Microwave treated Salvadora oleoides as an eco-friendly biosorbent for the removal of toxic methyl violet dye from aqueous solution--A green approach.

    PubMed

    Din, Muhammad Imran; Hussain, Zaib; Munir, Hifza; Naz, Amber; Intisar, Azeem; Makshoof, M Nouman; Mirza, M Latif

    2016-01-01

    In the present study, microwave treated Salvadora oleoides (MW-SO) has been investigated as a potential biosorbent for the removal of toxic methyl violet dye. A batch adsorption method was experimented for biosorptive removal of toxic methyl violet dye from the aqueous solution. The effect of various operating variables, viz., adsorbent dosage, pH, contact time and temperature on the removal of the dye was studied and it was found that nearly 99% removal of the dye was possible under optimum conditions. Kinetic study revealed that a pseudo-second-order mechanism was predominant and the overall process of the dye adsorption involved more than one step. Hence, in order to investigate the rate determining step, intra-particle diffusion model was applied. Adsorption equilibrium study was made by analyzing Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) adsorption isotherm models and the biosorption data was found to be best represented by the Langmuir model. The biosorption efficiency of MW-SO was also compared with unmodified material, Salvadora oleoides (SO). It was found that the sorption capacity (qmax) increased from 58.5 mg/g to 219.7 mg/g on MW treatment. Determination of thermodynamic parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) confirmed the spontaneous, endothermic and feasible nature of the adsorption process. The preparation of MW-SO did not require any additional chemical treatment and a high percentage removal of methyl violet dye was obtained in much lesser time. Thus, it is in agreement with the principles of green chemistry. The results of the present research work suggest that MW-SO can be used as an environmentally friendly and economical alternative biosorbent for the removal of methyl violet dye from aqueous solutions. PMID:26588059

  18. Aqueous photofate of crystal violet under simulated and natural solar irradiation: Kinetics, products, and pathways.

    PubMed

    Li, Yong; Yang, Shaogui; Sun, Cheng; Wang, Lianhong; Wang, Qingeng

    2016-01-01

    In this work photodegradation rates and pathways of an illegal veterinary drug, crystal violet, were studied under simulated and solar irradiation with the goal of assessing the potential of photolysis as a removal mechanism in the aquatic environment. Factors influencing the photodegradation process under simulated sunlight were investigated, including pH, humic acid, Fe(2+), Ca(2+), [Formula: see text] , and [Formula: see text] , of which favorable conditions were optimized by the orthogonal array design. The degradation processes of crystal violet conformed to pseudo first-order kinetics, with different rate constants under different conditions. Reactive oxygen species such as hydroxyl radical, singlet oxygen, and superoxide anion participated in the indirect photolysis process, leading to much higher decolorization efficiencies than those of direct photolysis and hydrolysis. Contrasting to simulated irradiation, solar irradiation led to complete decolorization. Sixty-four products were identified by high resolution liquid chromatography-time-of-flight mass spectrometry and gas chromatography-mass spectrometry, elucidating relatively complete mineralization through photolysis. Based on the analyses of the degradation products and calculations of the frontier electron density, transformation pathways were proposed as singlet oxygen addition, N-demethylation, hydroxyl addition, decomposition of conjugated structure, the removal of benzene ring and the ring-opening reaction. As a result, small products generated as carboxylic acids, alcohols and amines, which were not likely to cause severe hazards to the environment. This study provided both a reference for photodegradation of crystal violet and future safety applications and predictions of decontamination of related triphenylmethane veterinary drug under environmental conditions. PMID:26497275

  19. Experimental design approach applied to the elimination of crystal violet in water by electrocoagulation with Fe or Al electrodes.

    PubMed

    Durango-Usuga, Paula; Guzmán-Duque, Fernando; Mosteo, Rosa; Vazquez, Mario V; Peñuela, Gustavo; Torres-Palma, Ricardo A

    2010-07-15

    An experimental design methodology was applied to evaluate the decolourization of crystal violet (CV) dye by electrocoagulation using iron or aluminium electrodes. The effects and interactions of four parameters, initial pH (3-9), current density (6-28 A m(-2)), substrate concentration (50-200 mg L(-1)) and supporting electrolyte concentration (284-1420 mg L(-1) of Na(2)SO(4)), were optimized and evaluated. Although the results using iron anodes were better than for aluminium, the effects and interactions of the studied parameters were quite similar. With a confidence level of 95%, initial pH and supporting electrolyte concentration showed limited effects on the removal rate of CV, whereas current density, pollutant concentration and the interaction of both were significant. Reduced models taking into account significant variables and interactions between variables have shown good correlations with the experimental results. Under optimal conditions, almost complete removal of CV and chemical oxygen demand were obtained after electrocoagulation for 5 and 30 min, using iron and aluminium electrodes, respectively. These results indicate that electrocoagulation with iron anodes is a rapid, economical and effective alternative to the complete removal of CV in waters. Evolutions of pH and residual iron or aluminium concentrations in solution are also discussed. PMID:20303653

  20. A facile surface-enhanced Raman scattering (SERS) detection of rhodamine 6G and crystal violet using Au nanoparticle substrates

    NASA Astrophysics Data System (ADS)

    Zhang, Kuibao; Zeng, Tixian; Tan, Xiulan; Wu, Weidong; Tang, Yongjian; Zhang, Haibin

    2015-08-01

    In this study, Au nanoparticle (5 nm) colloid was employed for a facile preparation of SERS substrates from three approaches: (1) original Au nanoparticles, (b) Au colloid coated 200 nm polystyrene (PS) beads, and (3) Au colloid annealed at 200-500 °C. Rhodamine 6G (R6G) and crystal violet were employed as the Raman active probes. The Au colloid deposited PS beads (PS@Au) exhibit intensive SERS signal for R6G detection, which is promising for crystal violet detection after being annealed at 400 °C. The 200 °C annealed Au nanoparticles demonstrate excellent combined SERS sensitivity for both R6G and crystal violet. For the original Au colloid, elevated annealing temperature from 200 °C to 500 °C decreases the SERS intensity as Au particles were coarsened gradually.

  1. Application of Micro-cloud point extraction for spectrophotometric determination of Malachite green, Crystal violet and Rhodamine B in aqueous samples

    NASA Astrophysics Data System (ADS)

    Ghasemi, Elham; Kaykhaii, Massoud

    2016-07-01

    A novel, green, simple and fast method was developed for spectrophotometric determination of Malachite green, Crystal violet, and Rhodamine B in water samples based on Micro-cloud Point extraction (MCPE) at room temperature. This is the first report on the application of MCPE on dyes. In this method, to reach the cloud point at room temperature, the MCPE procedure was carried out in brine using Triton X-114 as a non-ionic surfactant. The factors influencing the extraction efficiency were investigated and optimized. Under the optimized condition, calibration curves were found to be linear in the concentration range of 0.06-0.60 mg/L, 0.10-0.80 mg/L, and 0.03-0.30 mg/L with the enrichment factors of 29.26, 85.47 and 28.36, respectively for Malachite green, Crystal violet, and Rhodamine B. Limit of detections were between 2.2 and 5.1 μg/L.

  2. Application of Micro-cloud point extraction for spectrophotometric determination of Malachite green, Crystal violet and Rhodamine B in aqueous samples.

    PubMed

    Ghasemi, Elham; Kaykhaii, Massoud

    2016-07-01

    A novel, green, simple and fast method was developed for spectrophotometric determination of Malachite green, Crystal violet, and Rhodamine B in water samples based on Micro-cloud Point extraction (MCPE) at room temperature. This is the first report on the application of MCPE on dyes. In this method, to reach the cloud point at room temperature, the MCPE procedure was carried out in brine using Triton X-114 as a non-ionic surfactant. The factors influencing the extraction efficiency were investigated and optimized. Under the optimized condition, calibration curves were found to be linear in the concentration range of 0.06-0.60mg/L, 0.10-0.80mg/L, and 0.03-0.30mg/L with the enrichment factors of 29.26, 85.47 and 28.36, respectively for Malachite green, Crystal violet, and Rhodamine B. Limit of detections were between 2.2 and 5.1μg/L. PMID:27085294

  3. Rapid reversible phototuning of lasing frequency in dye-doped cholesteric liquid crystal.

    PubMed

    Mykytiuk, T V; Ilchishin, I P; Yaroshchuk, O V; Kravchuk, R M; Li, Y; Li, Q

    2014-11-15

    Lasing in induced cholesteric liquid crystal (CLC) containing highly photosensitive azo chiral dopant (ChD) and pyrromethene laser dye was investigated. Due to the absence of excitation energy transfer from the dye molecules to the molecules of ChD in such a system, a low lasing threshold was achieved. When using violet and green light-emitting diodes, reversible frequency tuning was obtained in the range of about 30 nm with a tuning time 1-2 orders of magnitude smaller than in conventional CLC laser systems based on azo and azoxy photosensitive compounds. Further increase of the intensity of the excitation light by using a green laser pointer allowed us to achieve a record phototuning speed (∼21  nm in 148 ms). PMID:25490501

  4. Synthesis and characterisation of potassium polytitanate for photocatalytic degradation of crystal violet.

    PubMed

    Shahid, Mohammad; El Saliby, Ibrahim; McDonagh, Andrew; Tijing, Leonard D; Kim, Jong-Ho; Shon, Ho Kyong

    2014-11-01

    Potassium titanate nanostructures were synthesised by hydrothermal treatment of TiO2 (P25) in KOH and H2O2. As-produced powders were characterised by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption methods. Longitudinally-oriented-wire-like structures with a length up to several micrometres and diameters ranging from 10 to 30 nm were obtained. Larger size fibrous nanowires resulting from the hydrothermal treatment showed high affinity in adsorbing crystal violet (CV), which was mainly due to their high surface area. The photocatalytic bleaching of CV solution revealed that the wires are photoactive under ultraviolet light irradiation. Macroporous nanowires are considered as effective adsorbents of CV, capable of photocatalytic degradation, and they can be easily separated from the solution by settling. PMID:25458691

  5. SERS active Ag encapsulated Fe@SiO2 nanorods in electromagnetic wave absorption and crystal violet detection.

    PubMed

    Senapati, Samarpita; Srivastava, Suneel Kumar; Singh, Shiv Brat; Kulkarni, Ajit R

    2014-11-01

    The present work is focused on the preparation of Fe nanorods by the chemical reduction of FeCl3 (aq) using NaBH4 in the presence of glycerol as template followed by annealing of the product at 500°C in the presence of H2 gas flow. Subsequently, its surface has been modified by silica followed by silver nanoparticles to form silica coated Fe (Fe@SiO2) and Ag encapsulated Fe@SiO2 nanostructure employing the Stöber method and silver mirror reaction respectively. XRD pattern of the products confirmed the formation of bcc phase of iron and fcc phase of silver, though silica remained amorphous. FESEM images established the growth of iron nanorods from the annealed product and also formation of silica and silver coating on its surface. The appearance of the characteristics bands in FTIR confirmed the presence of SiO2 on the Fe surface. Magnetic measurements at room temperature indicated the ferromagnetic behavior of as prepared iron nanorods, Fe@SiO2 and silver encapsulated Fe@SiO2 nanostructures. All the samples exhibited strong microwave absorption property in the high frequency range (10GHz), though it is superior for Ag encapsulated Fe@SiO2 (-14.7dB) compared with Fe@SiO2 (-9.7dB) nanostructures of the same thickness. The synthesized Ag encapsulated Fe@SiO2 nanostructure also exhibited the SERS phenomena, which is useful in the detection of the carcinogenic dye crystal violet (CV) upto the concentration of 10(-10)M. All these findings clearly demonstrate that the Ag encapsulated Fe@SiO2 nanostructure could efficiently be used in the environmental remediation. PMID:25262081

  6. Use of hydrogen peroxide treatment and crystal violet agar plates for selective recovery of bacteriophages from natural environments

    SciTech Connect

    Asghari, A.; Farrah, S.R.; Bitton, G. )

    1992-04-01

    Hydrogen peroxide inactivated bacteriophages and bacteria at different rates. A concentration of 0.1% hydrogen peroxide reduced the numbers of several bacteria by an average of 94% but caused an average of 25% inactivation in the numbers of bacteriophages tested. Treating natural samples with hydrogen peroxide selectively reduced the indigenous bacterial flora and permitted better visualization of plaques of lawns of Escherichia coli C-3000. In some cases indigenous gram-positive bacteria were relatively resistant to hydrogen peroxide, but their growth could be limited by incorporation of crystal violet into the bottom agar used for plaque assays. The use of hydrogen peroxide treatment and crystal violet-containing plates permitted recovery of more phages from natural samples than did other procedures, such as chloroform pretreatment or the use of selective plating agar such as EC medium.

  7. Leuco-crystal-violet micelle gel dosimeters: I. Influence of recipe components and potential sensitizers.

    PubMed

    Nasr, A T; Alexander, K; Schreiner, L J; McAuley, K B

    2015-06-21

    Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that dose sensitivity and initial colour of the gel increases with increasing Triton x-100 (Tx100) concentration. Using Cetyl Trimethyl Ammonium Bromide (CTAB) in place of Tx100 produces gels that are nearly colourless prior to irradiation, but reduces the dose sensitivity. The separate effects of Tri-chloro acetic acid concentration and pH are investigated, revealing that controlling the pH near 3.6 is crucial for achieving high dose sensitivity. The sensitizing effect of chlorinated species on dose sensitivity is tested using 2,2,2-trichloroethanol (TCE), chloroform, and 1,1,1-trichloro-2-methyl-2-propanol hemihydrate. TCE gives the largest improvement in dose sensitivity and is recommended for use in micelle gel dosimeters because it is less volatile and safer to use than chloroform. Preliminary experiments on a new gel containing CTAB as the surfactant and TCE show that this new gel gives a dose sensitivity that is 24% higher than that of previous LCV micelle gels and is nearly colourless prior to irradiation. PMID:26020840

  8. Leuco-crystal-violet micelle gel dosimeters: II. Recipe optimization and testing.

    PubMed

    Nasr, A T; Alexander, K M; Olding, T; Schreiner, L J; McAuley, K B

    2015-06-21

    In this study, recipe optimization of Leuco Crystal Violet (LCV) micelle gels made with the surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) and the chemical sensitizer 2,2,2-trichloroethanol (TCE) was aided by a two-level three-factor designed experiment. The optimized recipe contains 0.75 mM LCV, 17.0 mM CTAB, 120 mM TCE, 25.0 mM tri-chloro acetic acid (TCAA), 4 wt% gelatin and ~96 wt% water. Dose sensitivity of the optimized gel is 1.5 times higher than that of Jordan's standard LCV micelle gel. Spatial integrity of the 3D dose distribution information in 1L phantoms filled with this recipe is maintained for >120 d. Unfortunately, phantoms made using the optimized recipe showed dose-rate dependence (14% difference in optical attenuation at the peak dose using electron beam irradiations at 100 and 400 MU min(-1)). Further testing suggests that the surfactant CTAB is the cause of this dose rate behaviour. PMID:26020119

  9. Synthesis and Characterisation of Silica-Modified Titania for Photocatalytic Decolouration of Crystal Violet.

    PubMed

    Shahid, Mohammad; El Saliby, Ibrahim; Tijing, Leonard D; McDonagh, Andrew; Park, Se Min; Lee, Kwang Young; Shon, Ho Kyong; Kim, Jong-Ho

    2015-07-01

    In the past few years, silica-modified titania has drawn increasing attention due to their special properties making them ideal candidates for a wide range of applications. In this study, we report a novel method for the synthesis of silica-modified titania by a sol-gel method using sodium silicate solution (1 M). The hydrolysis and condensation reactions of titanium dioxide (TiO2, Degussa Aeroxide® P25) in sodium silicate solution proceeded with citric acid (3 M) as a catalyst. The orbital shaking method was followed for the removal of sodium salt formed during the sol-gel process. Solvent exchange was carried out using methanol and hexane. Finally, chemical modification of the gel was conducted using trimethylchlorosilane followed by ambient pressure drying. The obtained silica-modified titania was characterised for nanostructural analysis using scanning electron microscopy and transmission electron microscopy. The nitrogen adsorption-desorption measurements were employed to investigate the BET surface area, pore structure and pore volume of specimens. Thermal gravimetric analysis showed exothermic peaks at temperature range of 90-190 °C representing the oxidation of organic groups from--Si-R network. The silica-modified titania showed high photocatalytic activity and an easy recovery using crystal violet as model water pollutant. PMID:26373134

  10. Determination of malachite green and crystal violet in processed fish products.

    PubMed

    Lee, Jun Bae; Kim, Hee Yun; Jang, Young Mi; Song, Ji Young; Woo, Sung Min; Park, Mi Sun; Lee, Hyun Sook; Lee, Soon Kyu; Kim, Meehye

    2010-07-01

    This paper presents analysis of malachite green (MG) and crystal violet (CV) residues in processed fish products. Samples were homogenized and extracted with ammonium acetate buffer and acetonitrile. The extracted residues were partitioned into dichloromethane, in situ oxidized to chromic forms with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and cleaned up on neutral alumina and propylsulfonic acid cation-exchange solid-phase extraction (SPE) cartridges. MG and CV were determined at 618 and 588 nm using HPLC with a visible detector (LC-VIS) and confirmed by LC-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The recoveries were as follows: MG (74.8-83.8%), LMG (80.0-88.4%), CV (68.6-73.9%), and LCV (85.5-90.0%). The method modified in this study has been evaluated by application in-house to a survey of 253 processed fish products. As a result of monitoring, MG and CV were positive in one shrimp and one eel sample, respectively. Our results showed that regular monitoring of these antibiotic residues is recommended for protection of public health. PMID:20544455

  11. Leuco-crystal-violet micelle gel dosimeters: I. Influence of recipe components and potential sensitizers

    NASA Astrophysics Data System (ADS)

    Nasr, A. T.; Alexander, K.; Schreiner, L. J.; McAuley, K. B.

    2015-06-01

    Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that dose sensitivity and initial colour of the gel increases with increasing Triton x-100 (Tx100) concentration. Using Cetyl Trimethyl Ammonium Bromide (CTAB) in place of Tx100 produces gels that are nearly colourless prior to irradiation, but reduces the dose sensitivity. The separate effects of Tri-chloro acetic acid concentration and pH are investigated, revealing that controlling the pH near 3.6 is crucial for achieving high dose sensitivity. The sensitizing effect of chlorinated species on dose sensitivity is tested using 2,2,2-trichloroethanol (TCE), chloroform, and 1,1,1-trichloro-2-methyl-2-propanol hemihydrate. TCE gives the largest improvement in dose sensitivity and is recommended for use in micelle gel dosimeters because it is less volatile and safer to use than chloroform. Preliminary experiments on a new gel containing CTAB as the surfactant and TCE show that this new gel gives a dose sensitivity that is 24% higher than that of previous LCV micelle gels and is nearly colourless prior to irradiation.

  12. Leuco-crystal-violet micelle gel dosimeters: II. Recipe optimization and testing

    NASA Astrophysics Data System (ADS)

    Nasr, A. T.; Alexander, K. M.; Olding, T.; Schreiner, L. J.; McAuley, K. B.

    2015-06-01

    In this study, recipe optimization of Leuco Crystal Violet (LCV) micelle gels made with the surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) and the chemical sensitizer 2,2,2-trichloroethanol (TCE) was aided by a two-level three-factor designed experiment. The optimized recipe contains 0.75 mM LCV, 17.0 mM CTAB, 120 mM TCE, 25.0 mM tri-chloro acetic acid (TCAA), 4 wt% gelatin and ~96 wt% water. Dose sensitivity of the optimized gel is 1.5 times higher than that of Jordan’s standard LCV micelle gel. Spatial integrity of the 3D dose distribution information in 1L phantoms filled with this recipe is maintained for  >120 d. Unfortunately, phantoms made using the optimized recipe showed dose-rate dependence (14% difference in optical attenuation at the peak dose using electron beam irradiations at 100 and 400 MU min-1). Further testing suggests that the surfactant CTAB is the cause of this dose rate behaviour.

  13. Colorimetric growth assay for epidermal cell cultures by their crystal violet binding capacity.

    PubMed

    Bonnekoh, B; Wevers, A; Jugert, F; Merk, H; Mahrle, G

    1989-01-01

    The application of a simple, rapid, and inexpensive colorimetric growth assay was tested for human epidermal cells subcultured in uncoated plastic dishes. Cell layers were incubated with a crystal violet (CV) solution (0.2% with ethanol 2% in 0.5 M Tris-Cl buffer, pH 7.8) for 10 min at room temperature. After rinsing with 0.5 M Tris-Cl (pH 7.8) the cell layer was dried and decolorized with a sodium-dodecylsulfate solution (0.5% with ethanol 50% in 0.5 M Tris-Cl, pH 7.8) for 60 min at 37 degrees C. The extinction of the supernatant was read at the absorption maximum of 586 nm. The protein content of attached cells as classical parameter for quantifying cell growth was strongly related to CV extinction with a correlation coefficient of r = 0.98. Furthermore, the subcellular protein binding qualities of CV were analyzed. The water-soluble protein fraction of cultured epidermal cells was separated by sodium-dodecylsulfate polyacrylamide gel electrophoresis and stained with CV. We found a staining pattern which was qualitatively very similar to that of Coomassie blue, however less intense. Keratin electrophoresis revealed an affinity of CV to the 48, 50, and 56 kD cytokeratins. In conclusion, this CV assay is a reliable and simple method for the monitoring of epidermal cell growth in cultures. PMID:2482013

  14. Investigation of the effect of magnetic particles on the Crystal Violet adsorption onto a novel nanocomposite based on κ-carrageenan-g-poly(methacrylic acid).

    PubMed

    Gholami, Mostafa; Vardini, Mohammad Taghi; Mahdavinia, Gholam Reza

    2016-01-20

    A novel nanocomposite hydrogel prepared by incorporating Fe3O4 magnetic nanoparticles into the κ-carrageenan-g-poly (methacrylic acid) with in situ polymerization and was characterized by FT-IR, XRD, SEM, TEM and VSM. Synthesized nanocomposite was used to adsorb Crystal Violet (CV) (cationic dye) in aqueous solution in a batch system. The research studies showed that the adsorption of CV can be impressed as a function of contact time, initial concentration of CV, pH and molar ratio of κ-carrageenan to poly(methacrylic acid). CV adsorption tests disclosed that it only takes 15 min to reach the equilibrium and adsorption capacity for this dye was 28.24 mg g(-1). Langmuir isotherm for equilibrium adsorption data was fitted well and the pseudo-second-order model can describe the adsorption kinetics. Thermodynamic parameters of ΔG°, ΔH° and ΔS° showed the endothermic nature of adsorption and a spontaneous process. PMID:26572412

  15. Final report on the safety assessment of Basic Violet 1, Basic Violet 3, and Basic Violet 4.

    PubMed

    Diamante, Catherine; Bergfeld, Wilma F; Belsito, Donald V; Klaassen, Curtis D; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Alan Andersen, F

    2009-01-01

    Basic Violet 3, Basic Violet 1, and Basic Violet 4 are triphenylmethane dyes that function as direct (nonoxidative) hair colorants. No current uses or use concentrations in cosmetics are reported. The term Gentian Violet is used synonymously with Basic Violet 1 and Basic Violet 3, although the chemical structures of these 2 dyes are not the same. The Cosmetic Ingredient Review Expert Panel noted that Basic Violet 1, 3, and 4 contain quaternary ammonium ions, and therefore the rate of penetration across the epidermis is expected to be slow. The panel concluded that because of the carcinogenic potential of these dyes, insufficient data exist to support the safety of Basic Violet 1, 3, and 4 in cosmetic formulation. Dermal absorption data and a risk assessment are needed to complete this safety assessment. PMID:20086192

  16. Effects of sonochemical parameters and inorganic ions during the sonochemical degradation of crystal violet in water.

    PubMed

    Guzman-Duque, Fernando; Pétrier, Christian; Pulgarin, Cesar; Peñuela, Gustavo; Torres-Palma, Ricardo A

    2011-01-01

    This work deals with the ultrasonic degradation (800 kHz) of crystal violet (CV) under different experimental conditions. The effects of saturating gas (argon, carbon dioxide and air), CV concentration (2.45-1225 μmol L(-1)), pH (3-9) and power (20-80 W) were evaluated. The best performances were obtained at 80 W with argon as a saturating gas. The pH had no significant effect. The influence of several water matrices containing anions (chloride, sulphate and bicarbonate) and cations (Fe(2+)) on the sonolytic degradation of CV was also investigated. Significant differences were not observed with the presence of chloride and sulphate. However, at relatively low pollutant concentration (2.45 μmol L(-1)) bicarbonate showed a particular effect: a high bicarbonate concentration (350 mmol L(-1)) produced a detrimental effect, while a low bicarbonate concentration (3 mmol L(-1)) increased the efficiency of the process. The presence of Fe(2+) (1 mmol L(-1)) also increased the CV (49 μmol L(-1)) degradation by 32% after 180 min. Analyses of intermediates by GC-MS led to the identification of several sonochemical by-products: N,N-dimethylaminobenzene, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino)benzophenone, and N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane. The presence of these aromatic structures showed that the main ultrasonic CV degradation pathway is linked to the reaction with *OH radicals. At the end of the treatment, these early products were converted into biodegradable organic by-products which could be easily treated in a subsequent biological treatment. PMID:20797896

  17. Synthesis, characterisation of polyaniline-Fe3O4 magnetic nanocomposite and its application for removal of an acid violet 19 dye

    NASA Astrophysics Data System (ADS)

    Patil, Manohar R.; Khairnar, Subhash D.; Shrivastava, V. S.

    2016-04-01

    The present work deals with the development of a new method for the removal of dyes from an aqueous solution using polyaniline (PANI)-Fe3O4 magnetic nanocomposite. It is synthesised in situ through self-polymerisation of monomer aniline. Photocatalytic degradation studies were carried out for cationic acid violet 19 (acid fuchsine) dye using PANI-Fe3O4 nanocomposite in aqueous solution. Different parameters like catalyst dose, contact time and pH have been studied to optimise reaction condition. The optimum conditions for the removal of the dye are initial concentration 20 mg/l, adsorbent dose 6 gm/l, pH 7. The EDS technique gives elemental composition of synthesised PANI-Fe3O4. The SEM and XRD studies were carried for morphological feature characteristics of PANI-Fe3O4 nanocomposite. The VSM (vibrating sample magnetometer) gives magnetic property of PANI-Fe3O4 nanocomposite; also FT-IR analysis gives characteristics frequency of synthesised PANI-Fe3O4. Besides the above studies kinetic study has also been carried out.

  18. Evaluation of crystal violet decolorization assay for minimal inhibitory concentration detection of primary antituberculosis drugs against Mycobacterium tuberculosis isolates*

    PubMed Central

    Coban, Ahmet Yilmaz; Akbal, Ahmet Ugur; Uzun, Meltem; Cayci, Yeliz Tanriverdi; Birinci, Asuman; Durupinar, Belma

    2016-01-01

    In this study we evaluated the crystal violet decolorization assay (CVDA) for detection of minimum inhibitory concentration (MIC) of antituberculosis drugs. 53 isolates were tested in this study and 13 of them were multidrug resistant (MDR) isolates. The antibiotics concentrations were 2-0.06 mg/L for isoniazid (INH) and rifampicin (RIF) and were 16-0.25 mg/L for streptomycin (STM) and ethambutol (EMB). Crystal violet (CV-25 mg/L) was added into the microwells on the seventh day of incubation and incubation was continued until decolorization. Decolorization of CV was the predictor of bacterial growth. Overall agreements for four drugs were detected as 98.1%, and the average time was detected as 9.5 ± 0.89 day after inoculation. One isolate for INH and two isolates for STM were determined resistant in the reference method, but susceptible by the CVDA. One isolate was susceptible to EMB by the reference method, but resistant by the CVDA. All results were concordant for RIF. This study shows that CVDA is a rapid, reliable and suitable for determination of MIC values of Mycobacterium tuberculosis. And it can be used easily especially in countries with limited-sources. PMID:27304025

  19. Evaluation of crystal violet decolorization assay for minimal inhibitory concentration detection of primary antituberculosis drugs against Mycobacterium tuberculosis isolates.

    PubMed

    Coban, Ahmet Yilmaz; Akbal, Ahmet Ugur; Uzun, Meltem; Cayci, Yeliz Tanriverdi; Birinci, Asuman; Durupinar, Belma

    2016-06-10

    In this study we evaluated the crystal violet decolorization assay (CVDA) for detection of minimum inhibitory concentration (MIC) of antituberculosis drugs. 53 isolates were tested in this study and 13 of them were multidrug resistant (MDR) isolates. The antibiotics concentrations were 2-0.06 mg/L for isoniazid (INH) and rifampicin (RIF) and were 16-0.25 mg/L for streptomycin (STM) and ethambutol (EMB). Crystal violet (CV-25 mg/L) was added into the microwells on the seventh day of incubation and incubation was continued until decolorization. Decolorization of CV was the predictor of bacterial growth. Overall agreements for four drugs were detected as 98.1%, and the average time was detected as 9.5 ± 0.89 day after inoculation. One isolate for INH and two isolates for STM were determined resistant in the reference method, but susceptible by the CVDA. One isolate was susceptible to EMB by the reference method, but resistant by the CVDA. All results were concordant for RIF. This study shows that CVDA is a rapid, reliable and suitable for determination of MIC values of Mycobacterium tuberculosis. And it can be used easily especially in countries with limited-sources. PMID:27304025

  20. Coloring and habit modification of dyed KDP crystals as functions of supersaturation and dye concentration

    NASA Astrophysics Data System (ADS)

    Hirota, Shouji; Miki, Hideo; Fukui, Keisuke; Maeda, Kouji

    2002-02-01

    Azo-organic dyes as additives were examined to make colored KDP (potassium dihydrogen phosphate) crystals. The dyes used here were amaranth and sunset-yellow FCF. Influences of supersaturation and dye concentration in the solution were observed on the color and crystal habit of KDP. Amaranth colored the pyramidal section (1 0 1) of the crystals in the solution at low supersaturation and high dye concentration. The highly supersaturated solutions produced entirely colored crystals. The crystal habit did not significantly change in the amaranth solution. Sunset-yellow FCF had a significant effect on the crystal habit and color of KDP, and the prismatic section of the crystals was decreased. Sunset-yellow FCF colored the whole KDP crystals in the solution at high dye concentration. The habit index of KDP crystal, which is the ratio of the pyramidal size to prismatic size, was discussed as a function of dye concentration and supersaturation.

  1. Localization microscopy of DNA in situ using Vybrant(®) DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single molecule resolution.

    PubMed

    Żurek-Biesiada, Dominika; Szczurek, Aleksander T; Prakash, Kirti; Mohana, Giriram K; Lee, Hyun-Keun; Roignant, Jean-Yves; Birk, Udo J; Dobrucki, Jurek W; Cremer, Christoph

    2016-05-01

    Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant(®) DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of DNA in nuclei of fixed mammalian cells. This SMLM method enabled optical isolation and localization of large numbers of DNA-bound molecules, usually in excess of 10(6) signals in one cell nucleus. The technique yielded high-quality images of nuclear DNA density, revealing subdiffraction chromatin structures of the size in the order of 100nm; the interchromatin compartment was visualized at unprecedented optical resolution. The approach offers several advantages over previously described high resolution DNA imaging methods, including high specificity, an ability to record images using a single wavelength excitation, and a higher density of single molecule signals than reported in previous SMLM studies. The method is compatible with DNA/multicolor SMLM imaging which employs simple staining methods suited also for conventional optical microscopy. PMID:26341267

  2. Spectrally-isolated violet to blue wavelength generation by cascaded degenerate four-wave mixing in a photonic crystal fiber.

    PubMed

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhang, Xianting; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Wang, Liang; Zhong, Kangping; Wang, Kuiru; Yu, Chongxiu; Tam, Hwa Yaw; Wai, P K A

    2016-06-01

    Generation of spectrally-isolated wavelengths in the violet to blue region based on cascaded degenerate four-wave mixing (FWM) is experimentally demonstrated for the first time in a tailor-made photonic crystal fiber, which has two adjacent zero dispersion wavelengths (ZDWs) at 696 and 852 nm in the fundamental mode. The influences of the wavelength λp and the input average power Pav of the femtosecond pump pulses on the phase-matched frequency conversion process are studied. When femtosecond pump pulses at λp of 880, 870, and 860 nm and Pav of 500 mW are coupled into the normal dispersion region close to the second ZDW, the first anti-Stokes waves generated near the first ZDW act as a secondary pump for the next FWM process. The conversion efficiency ηas2 of the second anti-Stokes waves, which are generated at the violet to blue wavelengths of 430, 456, and 472 nm, are 4.8, 6.48, and 9.66%, for λp equalling 880, 870, and 860 nm, respectively. PMID:27244427

  3. Feasibility study on the use of liquid crystal/dye cells for digital signage

    NASA Astrophysics Data System (ADS)

    Itaya, Shunsuke; Azumi, Nada Dianah B. M.; Ohta, Masamichi; Ozawa, Shintaro; Fujieda, Ichiro

    2016-03-01

    Elongated dye molecules orient themselves with surrounding liquid crystal molecules. We propose to incorporate such a guest-host cell in a screen of a projection display. This configuration might be applied for digital signage to be installed on building walls. Dual-mode operation is realized by the bias applied to the cell. In display-mode, the dye molecules are oriented in parallel to the substrate of the cell. When excited by ultra-violet light, photoluminescence (PL) is generated. Because it is mostly perpendicular to the long axis of the molecule, it exits the cell efficiently. In powerharvesting mode, they are oriented vertically. The PL generated by ambient light is directed to edge surfaces where solar cells are mounted. In experiment, we fabricated a cell with commonly-available materials (coumarin 6 and a nematic liquid crystal). Anti-parallel alignment condition was adopted. We recorded PL spectra from the cell for the two excitation conditions. First, the center of the cell was irradiated by a 1.69mW blue laser beam. Second, the whole cell was uniformly exposed to the light from a fluorescent lamp at illuminance of 800lx. From the measured spectra for these cases, the contrast of luminance is calculated to be 3.2 ×105 . This factor is improved to 5 7.5×105 by attaching a polarizer sheet on the cell surface. The optical power reaching its edge surfaces is measured and it roughly agrees with the prediction by a simple model neglecting self-absorption. Development of phosphor materials with a large Stokes shift is desired to boost performance of the proposed system.

  4. Deterministically Polarized Fluorescence from Single Dye Molecules Aligned in Liquid Crystal Host

    SciTech Connect

    Lukishova, S.G.; Schmid, A.W.; Knox, R.; Freivald, P.; Boyd, R. W.; Stroud, Jr., C. R.; Marshall, K.L.

    2005-09-30

    We demonstrated for the first time to our konwledge deterministically polarized fluorescence from single dye molecules. Planar aligned nematic liquid crystal hosts provide deterministic alignment of single dye molecules in a preferred direction.

  5. Photoluminescence analysis of self induced planer alignment in azo dye dispersed nematic liquid crystal complex

    SciTech Connect

    Kumar, Rishi Sood, Srishti Raina, K. K.

    2014-04-24

    We have developed azo dye doped nematic liquid crystal complex for advanced photonic liquid crystal display technology aspects. Disperse orange azo dye self introduced planer alignment in the nematic liquid crystal without any surface anchoring treatment. Planer alignment was characterized by optical polarizing microscopy. The electro-optical switching response of dye disperse planer aligned nematic cell was investigated as a function of applied voltage with the help of photoluminescence spectrophotometer for the tuning of photoluminescence contrast.

  6. Liquid-Crystal Photoalignment by Super Thin Azo Dye Layer

    NASA Astrophysics Data System (ADS)

    Li, Xihua; Kozenkov, Vladimir M.; Yeung, Fion Sze-Yan; Xu, Peizhi; Chigrinov, Vladimir G.; Kwok, Hoi-Sing

    2006-01-01

    A novel liquid crystal (LC) photoalignment method, based on a super thin azo dye molecular layer is proposed. The basic idea of this method is to form a very neat textile knitwear and uniform alignment by azo dye layer without spin coating and rubbing processes. The thickness of the alignment layer is smaller than 3 nm, which is much thinner than traditional PI alignment film. In addition to the advantages of a conventional photoalignment method, the use of super thin layer simplifies the alignment procedure, making possible a high electrooptical performance, good photo-tolerance and thermal stability, better adhesion on indium tin oxide (ITO) surface and compatibility with roll-to-roll process.

  7. Detection and identification of dyes in blue writing inks by LC-DAD-orbitrap MS.

    PubMed

    Sun, Qiran; Luo, Yiwen; Yang, Xu; Xiang, Ping; Shen, Min

    2016-04-01

    In the field of forensic questioned document examination, to identify dyes detected in inks not only provides a solid foundation for ink discrimination in forged contents identification, but also facilitates the investigation of ink origin or the study regarding ink dating. To detect and identify potential acid and basic dyes in blue writing inks, a liquid chromatography-diode array detection-Orbitrap mass spectrometry (LC-DAD-Orbitrap MS) method was established. Three sulfonic acid dyes (Acid blue 1, Acid blue 9 and Acid red 52) and six triphenylmethane basic dyes (Ethyl violet, Crystal violet, Methyl violet 2B, Basic blue 7, Victoria blue B and Victoria blue R) were employed as reference dyes for method development. Determination of the nine dyes was validated to evaluate the instrument performance, and it turned out to be sensitive and stable enough for quantification. The method was then applied in the screening analysis of ten blue roller ball pen inks and twenty blue ballpoint pen inks. As a result, including TPR (a de-methylated product of Crystal violet), ten known dyes and four unknown dyes were detected in the inks. The latter were further identified as a de-methylated product of Victoria blue B, Acid blue 104, Acid violet 49 and Acid blue 90, through analyzing their characteristic precursor and product ions acquired by Orbitrap MS with good mass accuracy. The results showed that the established method is capable of detecting and identifying potential dyes in blue writing inks. PMID:26894843

  8. Crystallization control of organic dyes in self-organized microdomes

    NASA Astrophysics Data System (ADS)

    Karthaus, Olaf; Kaga, Kazuaki; Kageyama, Hiroaki

    2004-09-01

    A dewetting process of an evaporating solution is used to form micrometer-sized amorphous droplets, or domes, of the solute on substrates such as silicon, mica, glass, and indium-tin-oxide. The dome size can be controlled by the casting conditions. Higher concentration and slower evaporation of the solvent leads to larger domes. Upon annealing, the dyes may crystallize and form polycrystalline or single crystalline domes or crystalline fibers. Photophysical properties of the domes were investigated and it was found that the absorption and fluorescence spectra depend on the aggregate kind (polycrystalline or single crystalline) and the dome size.

  9. Removal of Triphenylmethane Dyes by Bacterial Consortium

    PubMed Central

    Cheriaa, Jihane; Khaireddine, Monia; Rouabhia, Mahmoud; Bakhrouf, Amina

    2012-01-01

    A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila)-(CM-4) was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable color-removal capability against crystal violet (50 mg/L) and malachite green (50 mg/L) dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD) removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes. PMID:22623907

  10. Kinetics of the reaction of crystal violet with hydroxide ion in the critical solution of 2-butoxyethanol + water.

    PubMed

    Du, Zhongyu; Mao, Shiyan; Chen, Zhiyun; Shen, Weiguo

    2013-01-17

    The kinetics of alkaline fading of crystal violet (CV) has been studied by UV spectrophotometry and microcalorimetry in the critical binary solution of 2-butoxyethanol + water at the initial reaction stage and various temperatures. It was found that the first-order rate constants obtained from these two methods are well accorded with each other, and the temperature dependence of the rate constant obeyed the Arrhenius equation in a temperature region far from the critical point. The critical slowing down was detected by both methods near the critical point. A simple empirical crossover model was proposed and used to analyze the experimental data to obtain the critical exponents, which were 0.158 ± 0.013 and 0.133 ± 0.012 from UV spectrophotometry and microcalorimetry, respectively, and the former was in good agreement with the theoretical prediction of 0.151. The slight lower value derived from microcalorimetry was attributed to the stirring in the microcalorimeter, which weakened the critical reduction of the diffusion coefficient. PMID:23276229

  11. A new rapid colourimetric method for testing Mycobacterium tuberculosis susceptibility to isoniazid and rifampicin: a crystal violet decolourisation assay.

    PubMed

    Coban, Ahmet Yilmaz

    2014-04-01

    The aim of this study was to investigate the performance of a new and accurate method for the detection of isoniazid (INH) and rifampicin (RIF) resistance among Mycobacterium tuberculosis isolates using a crystal violet decolourisation assay (CVDA). Fifty-five M. tuberculosis isolates obtained from culture stocks stored at -80ºC were tested. After bacterial inoculation, the samples were incubated at 37ºC for seven days and 100 µL of CV (25 mg/L stock solution) was then added to the control and sample tubes. The tubes were incubated for an additional 24-48 h. CV (blue/purple) was decolourised in the presence of bacterial growth; thus, if CV lost its colour in a sample containing a drug, the tested isolate was reported as resistant. The sensitivity, specificity, positive predictive value, negative predictive value and agreement for INH were 92.5%, 96.4%, 96.1%, 93.1% and 94.5%, respectively, and 88.8%, 100%, 100%, 94.8% and 96.3%, respectively, for RIF. The results were obtained within eight-nine days. This study shows that CVDA is an effective method to detect M. tuberculosis resistance to INH and RIF in developing countries. This method is rapid, simple and inexpensive. Nonetheless, further studies are necessary before routine laboratory implementation. PMID:24676667

  12. Fabrication of Microcapsules for Dye-Doped Polymer-Dispersed Liquid Crystal-Based Smart Windows.

    PubMed

    Kim, Mingyun; Park, Kyun Joo; Seok, Seunghwan; Ok, Jong Min; Jung, Hee-Tae; Choe, Jaehoon; Kim, Do Hyun

    2015-08-19

    A dye-doped polymer-dispersed liquid crystal (PDLC) is an attractive material for application in smart windows. Smart windows using a PDLC can be operated simply and have a high contrast ratio compared to those of other devices that employed photochromic or thermochromic material. However, in conventional dye-doped PDLC methods, dye contamination can cause problems and has a limited degree of commercialization of electric smart windows. Here, we report on an approach to resolve dye-related problems by encapsulating the dye in monodispersed capsules. By encapsulation, a fabricated dye-doped PDLC had a contrast ratio of >120 at 600 nm. This fabrication method of encapsulating the dye in a core-shell structured microcapsule in a dye-doped PDLC device provides a practical platform for dye-doped PDLC-based smart windows. PMID:26192469

  13. Use of dye to distinguish salt and protein crystals under microcrystallization conditions

    NASA Technical Reports Server (NTRS)

    Cosenza, Larry (Inventor); Bray, Terry L. (Inventor); DeLucas, Lawrence J. (Inventor); Gester, Thomas E. (Inventor); Hamrick, David T. (Inventor)

    2007-01-01

    An improved method of screening crystal growth conditions is provided wherein molecules are crystallized from solutions containing dyes. These dyes are selectively incorporated or associated with crystals of particular character thereby rendering crystals of particular character colored and improving detection of the dyed crystals. A preferred method involves use of dyes in protein solutions overlayed by oil. Use of oil allows the use of small volumes of solution and facilitates the screening of large numbers of crystallization conditions in arrays using automated devices that dispense appropriate solutions to generate crystallization trials, overlay crystallization trials with an oil, provide appropriate conditions conducive to crystallization and enhance detection of dyed (colored) or undyed (uncolored) crystals that result.

  14. Cavity-enhanced frequency doubling from 795nm to 397.5nm ultra-violet coherent radiation with PPKTP crystals in the low pump power regime.

    PubMed

    Wen, Xin; Han, Yashuai; Bai, Jiandong; He, Jun; Wang, Yanhua; Yang, Baodong; Wang, Junmin

    2014-12-29

    We demonstrate a simple, compact and cost-efficient diode laser pumped frequency doubling system at 795 nm in the low power regime. In two configurations, a bow-tie four-mirror ring enhancement cavity with a PPKTP crystal inside and a semi-monolithic PPKTP enhancement cavity, we obtain 397.5nm ultra-violet coherent radiation of 35mW and 47mW respectively with a mode-matched fundamental power of about 110mW, corresponding to a conversion efficiency of 32% and 41%. The low loss semi-monolithic cavity leads to the better results. The constructed ultra-violet coherent radiation has good power stability and beam quality, and the system has huge potential in quantum optics and cold atom physics. PMID:25607194

  15. Crystallization of fused silica surfaces by ultra-violet laser irradiation

    NASA Astrophysics Data System (ADS)

    Hirata, Kazuya; Haraguchi, Koshi

    2012-07-01

    In recent years, the increased use of high power lasers has created problems in optical elements due to laser damage. The International Organization for Standardization (ISO) describes in a publication ISO 11254 a laser-power resilience (LPR) test which we used to verify that by flattening the glass substrate of an optical element, we could improve the resistance to laser damage. We report on an evaluation of two types of samples of fused silica substrate whose surface roughness differed (Ra = 0.20 nm and Ra = 0.13 nm) using customized on-line laser damage testing. To induce laser damage to samples, we used the fifth harmonic generation from a Nd:YAG pulse laser (wavelength: 213 nm, pulse width: 4 ns, repetition frequency: 20 Hz). Results show that flattening reduced the progression of laser damage in the meta-phase laser damage phase by 1/3 of that without flattening. However, pro-phase laser damage which started at fluence 2.39 J/cm2 was unrelated to surface roughness. To analyze the pro-phase laser damage, we used x-ray diffraction (XRD), Raman spectroscopy, and variable pressure-type scanning electron microscopy (VP-SEM). From XRD data, we observed XRD patterns of cristobalite (111), cristobalite (102), α-quartz (111), and β-quartz (102). Raman spectrum data showed an increase in the three-membered ring vibration (600 cm-1), four-membered ring vibration (490 cm-1), and many-membered ring vibration (450 cm-1, 390 cm-1, and 300 cm-1). We observed patchy crystallized areas on the sample surfaces in the VP-SEM images. Based on these experimental results, we believe that the dominant factors in pro-phase laser damage are their physical properties. Substrate and thin film material must be appropriately selected in producing an optical element with a high level of resilience to laser exposure.

  16. Expansion of the scope of AOAC first action method 2012.25 - single-laboratory validation of triphenylmethane dye and leuco metabolite analysis in shrimp, tilapia, catfish, and salmon by LC-MS/MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prior to conducting a collaborative study of AOAC First Action 2012.25 LC-MS/MS analytical method for the determination of residues of three triphenylmethane dyes (malachite green, crystal violet, and brilliant green) and their metabolites (leucomalachite green and leucocrystal violet) in seafood, a...

  17. Molecular Interactions in Monolayers οf Azo Dye/Liquid Crystal Mixtures at Interfaces

    NASA Astrophysics Data System (ADS)

    Bauman, D.; Płóciennik, A.; Inglot, K.

    2009-08-01

    Full Text PDF A study of azo dye/liquid crystal mixtures in monolayers formed at an air-water interface (the Langmuir films) and at a solid surface (the Langmuir-Blodgett films) has been performed. Five azo dyes with various molecular structure and the liquid crystal 4-octyl-4' cyanobiphenyl (8CB) have been used. The dyes have been added to the liquid crystal at various molar fractions. Surface pressure and surface potential versus mean molecular area isotherms for the Langmuir films have been recorded and information about intermolecular interactions at the air-water interface has been obtained. On the basis of electronic absorption measurements for the Langmuir and Langmuir-Blodgett films the conclusions about the ability of dyes molecules to form self aggregates at the interfaces have been drawn. The influence of the dye molecular structure and its concentration on aggregates' geometry has been found.

  18. Imposed Orientation of Dye Molecules by Liquid Crystals and an Electric Field.

    ERIC Educational Resources Information Center

    Sadlej-Sosnowska, Nina

    1980-01-01

    Describes experiments using dye solutions in liquid crystals in which polar molecules are oriented in an electrical field and devices are constructed to change their color in response to an electric signal. (CS)

  19. Surface Binding and Organization of Sensitizing Dyes on Metal Oxide Single Crystal Surfaces

    SciTech Connect

    Parkinson, Bruce

    2010-06-04

    Even though investigations of dye-sensitized nanocrystalline semiconductors in solar cells has dominated research on dye-sensitized semiconductors over the past two decades. Single crystal electrodes represent far simpler model systems for studying the sensitization process with a continuing train of studies dating back more than forty years. Even today single crystal surfaces prove to be more controlled experimental models for the study of dye-sensitized semiconductors than the nanocrystalline substrates. We analyzed the scientific advances in the model sensitized single crystal systems that preceded the introduction of nanocrystalline semiconductor electrodes. It then follows the single crystal research to the present, illustrating both their striking simplicity of use and clarity of interpretation relative to nanocrystalline electrodes. Researchers have employed many electrochemical, photochemical and scanning probe techniques for studying monolayer quantities of sensitizing dyes at specific crystallographic faces of different semiconductors. These methods include photochronocoulometry, electronic spectroscopy and flash photolysis of dyes at potential-controlled semiconductor electrodes and the use of total internal reflection methods. In addition, we describe the preparation of surfaces of single crystal SnS2 and TiO2 electrodes to serve as reproducible model systems for charge separation at dye sensitized solar cells. This process involves cleaving the SnS2 electrodes and a photoelectrochemical surface treatment for TiO2 that produces clean surfaces for sensitization (as verified by AFM) resulting in near unity yields for electron transfer from the molecular excited dyes into the conduction band.

  20. Photo-stimulated phase and anchoring transitions of chiral azo-dye doped nematic liquid crystals.

    PubMed

    Kundu, Sudarshan; Kang, Shin-Woong

    2013-12-16

    We report concurring phase and anchoring transitions of chiral azo-dye doped nematic liquid crystals. The transitions are induced by photo-stimulation and stable against light and thermal treatments. Photochromic trans- to cis-isomerization of azo-dye induces an augmented dipole moment and strong dipole-dipole interaction of the cis-isomers, resulting in the formation of nano-sized dye-aggregates. Consequent phase separation of the aggregates of a chiral azo-dye induces phase transition from a chiral to nonchiral nematic phase. In addition, the deposition of dye-aggregates at the surfaces brings about anchoring transition of LC molecules. The stability and irreversibility of the transition, together with no need of pretreatments for LC alignment, provide fascinating opportunity for liquid crystal device applications. PMID:24514707

  1. Intercalating dyes for enhanced contrast in second-harmonic generation imaging of protein crystals

    PubMed Central

    Newman, Justin A.; Scarborough, Nicole M.; Pogranichniy, Nicholas R.; Shrestha, Rashmi K.; Closser, Richard G.; Das, Chittaranjan; Simpson, Garth J.

    2015-01-01

    The second-harmonic generation (SHG) activity of protein crystals was found to be enhanced by up to ∼1000-fold by the intercalation of SHG phores within the crystal lattice. Unlike the intercalation of fluorophores, the SHG phores produced no significant background SHG from solvated dye or from dye intercalated into amorphous aggregates. The polarization-dependent SHG is consistent with the chromophores adopting the symmetry of the crystal lattice. In addition, the degree of enhancement for different symmetries of dyes is consistent with theoretical predictions based on the molecular nonlinear optical response. Kinetics studies indicate that intercalation arises over a timeframe of several minutes in lysozyme, with detectable enhancements within seconds. These results provide a potential means to increase the overall diversity of protein crystals and crystal sizes amenable to characterization by SHG microscopy. PMID:26143918

  2. Intercalating dyes for enhanced contrast in second-harmonic generation imaging of protein crystals.

    PubMed

    Newman, Justin A; Scarborough, Nicole M; Pogranichniy, Nicholas R; Shrestha, Rashmi K; Closser, Richard G; Das, Chittaranjan; Simpson, Garth J

    2015-07-01

    The second-harmonic generation (SHG) activity of protein crystals was found to be enhanced by up to ∼1000-fold by the intercalation of SHG phores within the crystal lattice. Unlike the intercalation of fluorophores, the SHG phores produced no significant background SHG from solvated dye or from dye intercalated into amorphous aggregates. The polarization-dependent SHG is consistent with the chromophores adopting the symmetry of the crystal lattice. In addition, the degree of enhancement for different symmetries of dyes is consistent with theoretical predictions based on the molecular nonlinear optical response. Kinetics studies indicate that intercalation arises over a timeframe of several minutes in lysozyme, with detectable enhancements within seconds. These results provide a potential means to increase the overall diversity of protein crystals and crystal sizes amenable to characterization by SHG microscopy. PMID:26143918

  3. A Case-Control Study of Oral Epithelial Proliferative Markers among Sudanese Toombak Dippers Using Micronuclei Assay, Argyrophilic Nucleolar Organizer Region, Papanicolaou and Crystal Violet Methods

    PubMed Central

    Anass, M. Abbas; G. Ahmed, Hussain

    2013-01-01

    The use of Toombak has been reported to play a major role in the etiology of oral cancer in Sudan. The cellular proliferative activity on the oral epithelium of 210 Toombak dippers was assessed by applying the micronuclei frequency, mean argyrophilic nucleolar organizer region (AgNOR) counts, Papanicolaou method, and 1% crystal violet stain. Participants were divided into 3 groups: 200 were apparently healthy individuals, 100 were Toombak users (cases), 100 were non-tobacco users (control) and 10 were patients with oral squamous cell carcinomas. Cytological atypia was identified among 4 (4%). Toombak users and was not found among the control group (P<0.04). The micronuclei frequencies were higher in Toombak users (1.026) than in the control group (0.356) (P<0.0001). The mean AgNOR counts in Toombak users (2.423) were higher than control group (1.303) (P<0.0001). Neither Toombak users nor control group showed mitotic figures in 1% crystal violet method. The results of this research showed that Toombak dipping is a high risk factor for increase in the cellular proliferation in the oral mucosa. The cytological proliferative marker methods used are useful for screening Toombak users. PMID:24179643

  4. Heterogeneous distribution of dye-labelled biomineralizaiton proteins in calcite crystals

    NASA Astrophysics Data System (ADS)

    Liu, Chuang; Xie, Liping; Zhang, Rongqing

    2015-12-01

    Biominerals are highly ordered crystals mediated by organic matters especially proteins in organisms. However, how specific proteins are distributed inside biominerals are not well understood. In the present study, we use fluorescein isothiocyanate (FITC) to label extracted proteins from the shells of bivalve Pinctada fucata. By confocal laser scanning microscopy (CLSM), we observe a heterogeneous distribution of dye-labelled proteins inside synthetic calcite at the microscale. Proteins from the prismatic calcite layers accumulate at the edge of crystals while proteins from the nacreous aragonite layers accumulate at the center of crystals. Raman and X-ray powder diffraction show that both the proteins cannot alter the crystal phase. Scanning electron microscope demonstrates both proteins are able to affect the crystal morphology. This study may provide a direct approach for the visualization of protein distributions in crystals by small-molecule dye-labelled proteins as the additives in the crystallization process and improve our understanding of intracrystalline proteins distribution in biogenic calcites.

  5. Orientational order of some liquid crystal/dye mixtures obtained from optical birefringence

    NASA Astrophysics Data System (ADS)

    Bielejewska, Natalia

    2016-04-01

    This study presents optical birefringence measurements as a function of temperature for the liquid crystal/dye mixtures. The optical birefringence of the liquid crystals used in liquid crystal displays technology is related to the order parameter , which is crucial from the development point of view. The properties of the dyes (4-dimethylamino-4‧-nitrostilbene and N,N‧-bis(2,5-di-tert-buthylphenyl)-3,4,9,10-perylenedicarboximide) as a guest molecule are tested over the whole region of nematic phase occurrence by three different methods: measurement with use of the plano-convex lens, Berek's compensator and photoelastic modulator.

  6. Photochronocoulometric measurement of the coverage of surface-bound dyes on titanium dioxide crystal surfaces.

    PubMed

    Lu, Yunfeng; Spitler, Mark T; Parkinson, B A

    2006-12-21

    Atomically flat terraced single-crystal anatase and rutile surfaces can be prepared allowing for the reproducible adsorption of covalently attached sensitizing dyes. Once reproducible surfaces and dye coverages are achieved, a photochronocoulometric technique is developed to measure the surface coverage of the dyes, an important parameter in determining the efficiency of sensitization. The surface-bound dyes are irreversibly oxidized by exposure to a light pulse with the n-type oxide semiconductor electrode held in depletion. A double-exponential decay of the subsequent photocurrent is then measured, where the integration of the faster decay is associated with the adsorbed dye coverage and the second much slower decay is attributed to trace regenerators, including water, in the nonaqueous electrolyte. The ruthenium-based N3 dye shows the expected linear dependence of the rate constant on light intensity whereas a dicarboxylated thiacyanine dye shows a square root dependence of its photooxidation rate on light intensity. The sublinear response of the thiacyanine dye is discussed in terms of the more complex surface chemistry that is known for this family of sensitizing dyes. PMID:17165972

  7. Phenylazoindole dyes - Part I: The syntheses, characterizations, crystal structures, quantum chemical calculations and antimicrobial properties

    NASA Astrophysics Data System (ADS)

    Seferoğlu, Zeynel; Yalçın, Ergin; Babür, Banu; Seferoğlu, Nurgül; Hökelek, Tuncer; Yılmaz, Ebru; Şahin, Ertan

    2013-09-01

    In this study, the synthesis of four new phenylazo indole dyes (dye 1-4) were carried out by diazotization of 4-aminoacetophenone and coupling with various 2- and 1,2-disubstituted indole derivatives. The dyes were characterized by UV-vis, FT-IR, 1H NMR, HRMS and X-ray single crystal diffraction methods. Azo-hydrazone tautomeric bahavior of the dyes in different solvents (DMSO, methanol, acetic acid and chloroform) was investigated by using 1H NMR and UV-vis results. The experimental results were compared with the corresponding calculated values. The results of experimental data and theoretical calculations showed that the azo tautomer is more stable than hydrazone tautomer. In addition to this, the antimicrobial activity of the dyes was also evaluated.

  8. Hydrogen bonding intermolecular effect on electro-optical response of doped 6PCH nematic liquid crystal with some azo dyes

    NASA Astrophysics Data System (ADS)

    Kiani, S.; Zakerhamidi, M. S.; Tajalli, H.

    2016-05-01

    Previous studies on the electro-optical responses of dye-doped liquid crystal have shown that dopant material have a considerable effect on their electro-optical responses. Despite the studies carried out on electro-optical properties of dye-doped liquid crystal, no attention has been paid to study of the interaction and structural effects in this procedure. In this paper, linear dyes and with similar structure were selected as dopants. The only difference in used dyes is the functional groups in their tails. So, doping of these dyes into liquid crystals determines the influence of interaction type on electro-optical behaviours of the doped systems. Therefore, in this work, two aminoazobenzene ("A-dye": hydrogen bond donor) and dimethyl-aminoazobenzene ("B-dye") dyes with different compositional percentages in liquid crystal host were used. Electro-optical Kerr behaviour, the pre-transition temperature and third order nonlinear susceptibility were investigated. The obtained results effectively revealed that type of interactions between the dye and liquid crystal is determinative of behavioral difference of doped system, compared to pure liquid crystal. Also, pre-transitional behaviour and thereupon Kerr electro-optical responses were affected by formed interactions into doped systems. In other words, it will be shown that addition of any dopants in liquid crystal, regardless of the nature of interactions, cannot cause appropriate electro-optical responses. In fact, type of dye, nature of interactions between dopant and liquid crystalline host as well as concentration of dye are the key factors in selecting the appropriate liquid crystal and dopant dye.

  9. Enhancement in ferroelectric, pyroelectric and photoluminescence properties in dye doped TGS crystals

    NASA Astrophysics Data System (ADS)

    Sinha, Nidhi; Goel, Neeti; Singh, B. K.; Gupta, M. K.; Kumar, Binay

    2012-06-01

    Pure and dye doped (0.1 and 0.2 mol%) Triglycine Sulfate (TGS) single crystals were grown by slow evaporation technique. A pyramidal coloring pattern, along with XRD and FT-IR studies confirmed the dye doping. Decrease in dielectric constant and increase in Curie temperature (Tc) were observed with increasing doping concentration. Low absorption cut off (231 nm) and high optical transparency (>90%) resulting in large band gap was observed in UV-VIS studies. In addition, strong hyper-luminescent emission bands at 350 and 375 nm were observed in which the relative intensity were found to be reversed as a result of doping. In P-E hysteresis loop studies, a higher curie temperature and an improved and more uniform figure of merit over a large region of the ferroelectric phase were observed. The improved dielectric, optical and ferroelectric/pyroelectric properties make the dye doped TGS crystals better candidate for various opto- and piezo-electronics applications.

  10. Effect of irradiation of swift heavy ions on dyes-doped KDP crystals for laser applications

    NASA Astrophysics Data System (ADS)

    Kumaresan, P.; Moorthy Babu, S.; Anbarasan, P. M.

    2008-04-01

    The organic dyes (amaranth, rhodamine and methyl orange) are doped in potassium dihydrogen phosphate (KDP) crystals. Influences of super saturation and dye concentration in the solution, on the color and crystal habit of KDP, were observed. Amaranth in the solution at low super saturation and high dye concentration colored the pyramidal section (1 0 1) of the crystals. The highly super saturated solutions produce entirely colored crystals. The concentration of dopants in the mother solution was varied from 0.1 to 10 mol%. The studies on pure and doped KDP crystals clearly indicate the effect of dopants on the crystal structure, in the absorption of IR frequencies and the non-linear optical property. Dye doping improves the NLO properties of the grown crystals. The frequencies with their relative intensities are obtained in FT-IR of pure and doped KDP. The very weak bands for dopants indicate its presence in low concentration. In view of the ever-growing importance of ion beams in optical material processing, this letter reports room temperature MeV Li + ion irradiation-induced depletion of hydrogen from single crystalline KDP which has wide applications as a non-linear optical material in optoelectronics technology. Irradiations have been performed using 50 MeV Li + ions up to a maximum dose of 2.4×10 15 ions cm -2. Simultaneously, detecting the elastically recoiled Li atoms has done hydrogen profiling. Bare KDP crystals show hydrogen loss of 72% at the maximum dose whereas Au-coated samples show that 60 Au layer acts as a barrier to considerably reduce hydrogen depletion from KDP. A possible explanation of these phenomena is suggested.

  11. Optically recorded tunable microlenses based on dye-doped liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Lucchetti, Liana; Tasseva, Jordanka

    2012-04-01

    We report on optically recorded microlenses in conventional liquid crystal cells doped with the azo-dye methyl-red. The focal length can be tuned electrically and changed in a wide range with just a small variation of the applied dc voltage. No patterned electrodes, built-in polymeric lens, or patterned molecular reorientation are required.

  12. Temperature tuning of lasing emission from dye-doped liquid crystal at intermediate twisted phase

    NASA Astrophysics Data System (ADS)

    Liao, Kuan-Cheng; Lin, Ja-Hon; Jian, Li-Hao; Chen, Yao-Hui; Wu, Jin-Jei

    2015-07-01

    Temperature tuning of lasing emission from dye-doped cholesteric liquid crystal (CLC) at intermediate twisted phase has been demonstrated in this work. With heavily doping of 42.5% chiral molecules into the nematic liquid crystals, the shifts of photonic bandgap versus temperature is obviously as thermal controlling of the sample below the certain value. By the differential scanning calorimetr measuremet, we demonstrate the phase transition from the CLC to the smectic phase when the temperature is lowered to be about 15°C. Between CLC and smectic phase, the liquid crystal mixtures are operated at intermediate twisted phase that can be used the temperature related refractive mirror. After pump by the Q-switched Nd:YAG laser, the lasing emission from this dye doped LC mixtures has been demonstrated whose emission wavelength can be tuned from 566 to 637 nm with 1.4°C variation.

  13. Enhancement in ferroelectric, pyroelectric and photoluminescence properties in dye doped TGS crystals

    SciTech Connect

    Sinha, Nidhi; Goel, Neeti; Singh, B.K.; Gupta, M.K.; Kumar, Binay

    2012-06-15

    Pure and dye doped (0.1 and 0.2 mol%) Triglycine Sulfate (TGS) single crystals were grown by slow evaporation technique. A pyramidal coloring pattern, along with XRD and FT-IR studies confirmed the dye doping. Decrease in dielectric constant and increase in Curie temperature (T{sub c}) were observed with increasing doping concentration. Low absorption cut off (231 nm) and high optical transparency (>90%) resulting in large band gap was observed in UV-VIS studies. In addition, strong hyper-luminescent emission bands at 350 and 375 nm were observed in which the relative intensity were found to be reversed as a result of doping. In P-E hysteresis loop studies, a higher curie temperature and an improved and more uniform figure of merit over a large region of the ferroelectric phase were observed. The improved dielectric, optical and ferroelectric/pyroelectric properties make the dye doped TGS crystals better candidate for various opto- and piezo-electronics applications. - Graphical abstract: Dye doping in TGS crystal resulted in hourglass morphology, increased hyper-luminescence intensity, improved T{sub c} and figure of merit. Highlights: Black-Right-Pointing-Pointer Amaranth dye doping in TGS crystals resulted in hourglass morphology. Black-Right-Pointing-Pointer Doping resulted in enhancement of Curie temperature from 49 to 53 Degree-Sign C. Black-Right-Pointing-Pointer Low cut off (230 nm) and wider transmittance window observed. Black-Right-Pointing-Pointer Strong hyper-luminescent emission bands at 350 and 375 nm were observed. Black-Right-Pointing-Pointer High and uniform figure of merit in ferroelectric phase was obtained.

  14. Heterogeneous distribution of dye-labelled biomineralizaiton proteins in calcite crystals

    PubMed Central

    Liu, Chuang; Xie, Liping; Zhang, Rongqing

    2015-01-01

    Biominerals are highly ordered crystals mediated by organic matters especially proteins in organisms. However, how specific proteins are distributed inside biominerals are not well understood. In the present study, we use fluorescein isothiocyanate (FITC) to label extracted proteins from the shells of bivalve Pinctada fucata. By confocal laser scanning microscopy (CLSM), we observe a heterogeneous distribution of dye-labelled proteins inside synthetic calcite at the microscale. Proteins from the prismatic calcite layers accumulate at the edge of crystals while proteins from the nacreous aragonite layers accumulate at the center of crystals. Raman and X-ray powder diffraction show that both the proteins cannot alter the crystal phase. Scanning electron microscope demonstrates both proteins are able to affect the crystal morphology. This study may provide a direct approach for the visualization of protein distributions in crystals by small-molecule dye-labelled proteins as the additives in the crystallization process and improve our understanding of intracrystalline proteins distribution in biogenic calcites. PMID:26675363

  15. Transition Metal Dithiolene Near-IR Dyes and Thier Applications in Liquid Crystal Devices

    SciTech Connect

    Marshall, K.L.; Painter, G.; Lotito, K.; Noto, A.G.; Chang, P.

    2006-08-18

    Numerous commercial and military applications exist for guest–host liquid crystal (LC) devices operating in the near- to mid-IR region. Progress in this area has been hindered by the severe lack of near-IR dyes with good solubility in the LC host, low impact on the inherent order of the LC phase, good thermal and chemical stability, and a large absorbance maximum tunable by structural modification over a broad range of the near-IR region. Transition metal complexes based on nickel, palladium, or platinum dithiolene cores show substantial promise in meeting these requirements. In this paper, we overview our past and present activities in the design and synthesis of transition metal dithiolene dyes, show some specific applications examples for these materials as near-IR dyes in LC electro-optical devices, and present our most recent results in the computational modeling of physical and optical properties of this interesting class of organometallic optical materials.

  16. Comparative study of raw and chemically treated mangrove leaf for remediation of 304 Methyl Violet 2B dye from aqueous solution: thermo-kinetics aspect.

    PubMed

    Bano, Bakht; Zahir, Erum

    2016-01-01

    The adsorption process is the most attractive alternative way for the treatment of industrial effluents. The main objective of the study is to compare the efficacy of adsorption by raw and chemically treated forms of mangrove plant leaf powder. It acts as adsorbent, and would not only be economical but also help to reduce pollution. The adsorbent was characterized by Fourier transform infra-red spectroscopy and scanning electron microscopy. Results showed that percent removal of dye was higher by chemically treated mangrove leaf (98%) than by raw mangrove leaf (75%) under all determined conditions. The equilibrium and kinetics adsorption data were analyzed by the Langmuir isotherm and the pseudo second order model. They were found to be the best fit to interpret the present data. The thermodynamic parameters were calculated by using the Langmuir equilibrium constant. Results suggested that dye adsorption on mangrove leaf was a spontaneous and exothermic process with enthalpy change = -15.26 kJ/mol, and there was decrease in disorder with entropy change = -5.089 kJ/mol K. PMID:27003070

  17. Efficient removal of crystal violet using Fe3O4-coated biochar: the role of the Fe3O4 nanoparticles and modeling study their adsorption behavior

    NASA Astrophysics Data System (ADS)

    Sun, Pengfei; Hui, Cai; Azim Khan, Rashid; Du, Jingting; Zhang, Qichun; Zhao, Yu-Hua

    2015-07-01

    Biochar shows great promise for use in adsorbing pollutants. However, a process for enhancing its adsorption capacity and re-collection efficiency is yet to be further developed. Hence, in this study, we developed a type of biochar coated with magnetic Fe3O4 nanoparticles (i.e., magnetic biochar (MBC)) and assessed its use for crystal violet (CV) adsorption as well as its recycling potential. The coating of Fe3O4 nanoparticles, which was not only on the surface, but also in the interior of biochar, performed two functions. Firstly, it produced a saturation magnetization of 61.48 emu/g, which enabled the biochar being efficiently re-collected using a magnet. Secondly, it significantly enhanced the adsorption capacity of the biochar (from 80.36 to 99.19 mg/g). The adsorption capacity of the MBC was determined to be the largest by so far (349.40 mg/g) for an initial CV concentration of 400 mg/L, pH of 6.0, and temperature of 40 °C, and the adsorption capacity of re-collected MBC was 73.31 mg/g. The adsorption of CV by the MBC was found to be a spontaneous and endothermic physical process in which the intraparticle diffusion was the limiting step. These findings inspire us to use other similar materials to tackle the menace of pollutions.

  18. Efficient removal of crystal violet using Fe3O4-coated biochar: the role of the Fe3O4 nanoparticles and modeling study their adsorption behavior

    PubMed Central

    Sun, Pengfei; Hui, Cai; Azim Khan, Rashid; Du, Jingting; Zhang, Qichun; Zhao, Yu-Hua

    2015-01-01

    Biochar shows great promise for use in adsorbing pollutants. However, a process for enhancing its adsorption capacity and re-collection efficiency is yet to be further developed. Hence, in this study, we developed a type of biochar coated with magnetic Fe3O4 nanoparticles (i.e., magnetic biochar (MBC)) and assessed its use for crystal violet (CV) adsorption as well as its recycling potential. The coating of Fe3O4 nanoparticles, which was not only on the surface, but also in the interior of biochar, performed two functions. Firstly, it produced a saturation magnetization of 61.48 emu/g, which enabled the biochar being efficiently re-collected using a magnet. Secondly, it significantly enhanced the adsorption capacity of the biochar (from 80.36 to 99.19 mg/g). The adsorption capacity of the MBC was determined to be the largest by so far (349.40 mg/g) for an initial CV concentration of 400 mg/L, pH of 6.0, and temperature of 40 °C, and the adsorption capacity of re-collected MBC was 73.31 mg/g. The adsorption of CV by the MBC was found to be a spontaneous and endothermic physical process in which the intraparticle diffusion was the limiting step. These findings inspire us to use other similar materials to tackle the menace of pollutions. PMID:26220603

  19. Controlled hydrothermal synthesis of BiOxCly/BiOmIn composites exhibiting visible-light photocatalytic degradation of crystal violet.

    PubMed

    Jiang, Yu-Rou; Lin, Ho-Pan; Chung, Wen-Hsin; Dai, Yong-Ming; Lin, Wan-Yu; Chen, Chiing-Chang

    2015-01-01

    A series of BiOxCly/BiOmIn composites were prepared using autoclave hydrothermal methods. The composition and morphologies of the BiOxCly/BiOmIn composites were controlled by adjusting the experimental conditions: the reaction pH value, temperature, and KCl/KI molar ratio. The products were characterized using X-ray diffraction, scanning electron microscopy-electron dispersive X-ray spectroscopy, UV-vis diffuse reflectance spectroscopy, Brunauer-Emmett-Teller specific surface areas, cathodoluminescence, high-resolution transmission electron microscopy, and high-resolution X-ray photoelectron spectroscopy. The photocatalytic efficiencies of composite powder suspensions were evaluated by monitoring the crystal violet (CV) concentrations. In addition, the quenching effects of various scavengers indicated that the reactive O2(-) played a major role, and OH or h(+) played a minor role in CV degradation. The intermediates formed during the decomposition process were isolated, identified, and characterized using high performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry to elucidate the CV decomposition mechanism. PMID:25464322

  20. The electrically and magnetically controllable random laser from dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Ye, Lihua; Liu, Bo; Zhao, Chong; Wang, Yan; Cui, Yiping; Lu, Yanqing

    2014-08-01

    The electrically and magnetically controllable random laser from dye-doped liquid crystals (LCs) was studied. The rubbing-alignment of the polyimide in the LC cell influenced the threshold voltage and the response time of the electrically controllable random laser. When the applied electric field was increased, the response time of the random laser decreased. The magnetically controllable random laser was studied in the hollow fiber structure, of which the response time was less than 1 s.

  1. Enhancement of the fluorescence of triphenylmethane dyes caused by their interaction with nanoparticles from β-diketonate complexes

    NASA Astrophysics Data System (ADS)

    Sveshnikova, E. B.; Ermolaev, V. L.

    2014-08-01

    We have studied the absorption and fluorescence spectra of Malachite Green and Crystal Violet in aqueous and alcoholic-aqueous solutions in which nanoparticles from Ln(III) and Sc(III) diketonates are formed at concentrations of complexes in a solution of 5-30 μM. We have shown that, if the concentrations of the dyes in the solution are lower than 0.5 μM, dye molecules are incorporated completely into nanoparticles or are precipitated onto their surface. The fluorescence intensity of these incorporated and adsorbed Malachite Green and Crystal Violet molecules increases by several orders of magnitude compared to the solution, which takes place because of a sharp increase in the fluorescence quantum yields of these dyes and at the expense of the sensitization of their fluorescence upon energy transfer from β-diketonate complexes entering into the composition of nanoparticles. We have shown that, if there is no concentration quenching, the values of the fluorescence quantum yield of the Crystal Violet dye incorporated into nanoparticles and adsorbed on their surface vary from 0.06 to 0.13, i.e., are close to the fluorescence quantum yield of this dye in solid solutions of sucrose acetate at room temperature. The independence of the fluorescence quantum yield of Crystal Violet on the morphology of nanoparticles testifies to a high binding constant of complexes and the dye. The considerable fluorescence quantum yields of triphenylmethane dyes in nanoparticles and sensitization of their fluorescence by nanoparticle-forming complexes make it possible to determine the concentration of these dyes in aqueous solutions by the luminescent method in the range of up to 1 nM.

  2. Single-Photon Source for Quantum Information Based on Single Dye Molecule Fluorescence in Liquid Crystal Host

    SciTech Connect

    Lukishova, S.G.; Knox, R.P.; Freivald, P.; McNamara, A.; Boyd, R.W.; Stroud, Jr., C.R.; Schmid, A.W.; Marshall, K.L.

    2006-08-18

    This paper describes a new application for liquid crystals: quantum information technology. A deterministically polarized single-photon source that efficiently produces photons exhibiting antibunching is a pivotal hardware element in absolutely secure quantum communication. Planar-aligned nematic liquid crystal hosts deterministically align the single dye molecules which produce deterministically polarized single (antibunched) photons. In addition, 1-D photonic bandgap cholesteric liquid crystals will increase single-photon source efficiency. The experiments and challenges in the observation of deterministically polarized fluorescence from single dye molecules in planar-aligned glassy nematic-liquid-crystal oligomer as well as photon antibunching in glassy cholesteric oligomer are described for the first time.

  3. Immobilization of Laccase in Alginate-Gelatin Mixed Gel and Decolorization of Synthetic Dyes

    PubMed Central

    Mogharabi, Mehdi; Nassiri-Koopaei, Nasser; Bozorgi-Koushalshahi, Maryam; Nafissi-Varcheh, Nastaran; Bagherzadeh, Ghodsieh; Faramarzi, Mohammad Ali

    2012-01-01

    Alginate-gelatin mixed gel was applied to immobilized laccase for decolorization of some synthetic dyes including crystal violet. The immobilization procedure was accomplished by adding alginate to a gelatin solution containing the enzyme and the subsequent dropwise addition of the mixture into a stirred CaCl2 solution. The obtained data showed that both immobilized and free enzymes acted optimally at 50°C for removal of crystal violet, but the entrapped enzyme showed higher thermal stability compared to the free enzyme. The immobilized enzyme represented optimum decolorization at pH 8. Reusability of the entrapped laccase was also studied and the results showed that ca. 85% activity was retained after five successive cycles. The best removal condition was applied for decolorization of seven other synthetic dyes. Results showed that the maximum and minimum dye removal was related to amido black 10B and eosin, respectively. PMID:22899898

  4. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.

    PubMed

    Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin

    2016-07-28

    In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs. PMID:27356177

  5. Nanoparticles assembled by aptamers and crystal violet for arsenic(iii) detection in aqueous solution based on a resonance Rayleigh scattering spectral assay

    NASA Astrophysics Data System (ADS)

    Wu, Yuangen; Zhan, Shenshan; Xing, Haibo; He, Lan; Xu, Lurong; Zhou, Pei

    2012-10-01

    Aptamer-assembled nanomaterials have captured much attention from the field of analytical chemistry in recent years. Although they have been regarded as a promising tool for heavy metal monitoring, report involving aptamer-based biosensors for arsenic detection are rare. Herein we developed a highly sensitive and selective aptamer biosensor for As(iii) detection based on a Resonance Rayleigh Scattering (RRS) spectral assay. Prior to As(iii) detection, we firstly assembled a variety of nanoparticles with different sizes via controlling the concentration of arsenic-binding aptamers in crystal violet (CV) solutions. The results of photon correlation spectroscopy (PCS) and scanning probe microscope (SPM) testified that the introduction of As(iii) had indeed changed the size of nanoparticles, which caused a great variation in the RRS intensity at 310 nm. In the presence of 100 ppb As(iii), a maximum decline in the ratio of RRS intensity was achieved for large nanoparticles assembled from 200 nM of aptamers and CV molecules, where the average size of nanoparticles had decreased from 273 nm to 168 nm. In the case of small nanoparticles, the maximum increase ratio of the RRS intensity was obtained when the concentration of aptamer was over 600 nM. Combined with an RRS spectral assay, an effective biosensor has been developed for As(iii) detection, using the above large and small nanoparticles as the target recognition element. The present biosensor has a detection limit as low as 0.2 ppb, a dynamic range from 0.1 ppb to 200 ppb, and high selectivity over other metal ions. Such an efficient biosensor will play an important role in environmental detection.

  6. Yellow-to-violet, blue, and green frequency upconversions in Nd3+-doped PbWO4 single crystal

    NASA Astrophysics Data System (ADS)

    Huang, Yanlin; Jang, Kyoung Hyuk; Seo, Hyo Jin; Jang, Kiwan

    2006-10-01

    Upconversion emission properties of Nd3+ ions doped in PbWO4 crystal are investigated by pulsed laser excitation into the G5/24+G2(1)7/2 levels at temperatures from 10to295K. The main upconversion emission consists of strong blue emission bands in the wavelength region of 435-447nm corresponding to the P1/22→I9/24 transitions. Some UV bands located in the wavelength region of 356-397nm corresponding to the D3/24→I9/24, I11/24, and I13/24 transitions and weak green emission at 525.2nm corresponding to the G7/24→I9/24 transition are observed. Several upconversion blue emissions from the P1/22 level and the absoprtion lines due to the I9/24→P1/22 transition indicate multisite structure of the Nd3+ ions in the PbWO4 lattices. We investigate the excitation spectra of the upconversion emissions and their pump power dependence and lifetimes from which the probable upconversion mechanisms are proposed and analyzed. The dominant mechanisms for the upconversion emission originating from the D3/24 level (UV emission) and the P1/22 level (blue emission) are proven to be the sequential two-photon excited-state absorption, while the energy transfer upconversion process is responsible for the green upconversion emission from the G7/24 level of Nd3+.

  7. Integration of biological photonic crystals in dye-sensitized solar cells for enhanced photocurrent generation

    NASA Astrophysics Data System (ADS)

    Campbell, Jeremy; Rorrer, Greg

    2013-10-01

    Dye-sensitized solar cells (DSSCs) rely on a network of titanium dioxide nanoparticles for electron transport and must balance carrier generation and collection. Adding photonic structures may increase light capture without affecting carrier collection. Diatoms are single-celled algae that biologically fabricate silicon dioxide cell walls which resemble photonic crystal slabs. We present a simple fabrication strategy that allows for uniform and controlled placement of biosilica within DSSCs. Integration of biosilica reduces photoanode transmittance to less than 5% prior to dye sensitization at loading levels as low as 6 wt% biosilica. Increased biosilica loading (17 wt%) provides additional enhancements in photocurrent generation. Reflectance measurements suggest that the enhancement results from the combined effects of photonic resonance and Mie scattering. Overall efficiency of these devices is improved by 8% and 14%, respectively.

  8. High-efficiency intracavity frequency doubling of a styryl-9 dye laserwith KNbO/sub 3/ crystals

    SciTech Connect

    Baumert, J.; Hoffnagle, J.; Guenter, P.

    1985-05-01

    Efficient (1.1%) frequency doubling of a low power cw (single frequency) dye laser at 850--870-nm wavelengths in KNbO/sub 3/ has been demonstrated. The fundamental power on the crystal was enhanced by (i) use of a passive resonator and (ii) by mounting the crystal within the dye laser resonator. The room temperature noncritical phase-matching wavelength for the nonlinear optical coefficient d/sub 32/ = (20.5 +- 0.3)pm/V has been determined to be lambda/sub pm/ = (859.7 +- 0.3) nm for the KNbO/sub 3/ crystals used in these experiments.

  9. Transition metal dithiolene complexes as near-IR dyes for liquid crystal device applications

    NASA Astrophysics Data System (ADS)

    Marshall, Kenneth L.; Schudel, Benjamin; Lippa, Irene A.

    2004-01-01

    Both commercial and military applications (e.g., free-space IR communications and sensor protection) exist for guest-host liquid crystal (LC) devices operating in the near- to mid-IR region. Progress in this area has been hindered by the severe lack of near-IR dyes with good solubility in the LC host, low impact on the inherent order of the LC phase, good thermal and chemical stability, and a large absorbance maximum tunable by structural modification over a broad range of the near-IR region. Transition metal complexes based on nickel, palladium, or platinum dithiolene cores show substantial promise in meeting these requirements. These new dye complexes are extraordinarily stable, possess liquid crystalline phases in their own right with the proper terminal functional groups, and can have melting points below room temperature. The latter property is especially significant for producing liquid crystal/dye mixtures with both high dye concentration and good resistance to phase separation. Because they are zerovalent, they can exhibit high solubility in LC hosts (up to 10 wt%). The λmax in these materials can range from 600 nm to 1600 nm, depending on structure. With enantiomerically enriched terminal substituents, nickel dithiolenes can induce a chiral mesophase in a nonchiral nematic host. This finding opens the possibility of generating novel LC mixtures with two degrees of tunability: an electronic absorbance band tunable by synthesis, and a selective reflection band tunable by temperature or applied electric field. Such a materials system would be particularly advantageous in sensor protection for dealing with frequency-agile laser threats.

  10. Light-induced effects in dye-doped liquid crystals: role of space charges

    NASA Astrophysics Data System (ADS)

    Simoni, F.; Lucchetti, L.

    2014-10-01

    We report the experimental demonstration that both the extra-ordinarily large nonlinear response and the light-induced permanent reorientation in liquid crystals doped by the azo-dye Methyl-Red originates from the modification of the charge density on the irradiated surface. By recording the sample response by applying dc or ac voltage, it is shown that in the latter case no permanent anchoring is possible. It is also demonstrated the limited role of photo-isomerization that gives a contribution to the nonlinear reorientation process only in the high dose regime. The effects on light-induced tuning of the Freedericksz transition are also reported.

  11. Director sliding induced by a circularly polarised light in dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Lucchetti, L.; Tifi, L.; Simoni, F.

    2008-09-01

    We report the first detailed experimental study of the transient effects of a circularly polarised beam on dye-doped liquid crystal cells. Experiments show that, as linearly polarized light does, light with circular polarization induces quasi-free sliding of the molecular director on the irradiated surface. The behaviour of the sliding angle vs. the incident intensity, its dependence on the exposure time and its independence on the sign of the light ellipticity, suggest that the phenomenon is connected to surface effects instead of being directly due to the transfer of intrinsic angular momentum from light to the LC molecules.

  12. Transflective spatial filter based on azo-dye-doped cholesteric liquid crystal films

    SciTech Connect

    Lin, T.-H.; Fuh, Andy Y.-G.

    2005-07-04

    This work demonstrates the feasibility of exploiting the photoisomerization effect in azo-dye-doped cholesteric liquid crystal (DDCLC) films with a concomitant decline of the phase transition temperature from the cholesteric to an isotropic phase (T{sub Ch-I}) as a spatial filter. The fabrication depends on the fact that the various intensities of the diffracted orders are responsible for the various degrees of transparency associated with the photoisomerized DDCLC film. High- and low-pass images in the Fourier optical signal process can be simultaneously observed via reflected and transmitted signals, respectively. A simulation is also performed, and the results are consistent closely with experimental data.

  13. Impact of Photo-Induced Surface Adsorption of Azo-Dyes on the Liquid Crystal Anchoring Conditions

    NASA Astrophysics Data System (ADS)

    Statman, David

    2013-03-01

    Using optical techniques, we measured the anchoring conditions of azo-dye doped nematic liquid crystals on rubbed polyimide surfaces. Linearly polarized light induces the formation of a second easy axis on the polymer surface oriented toward the polarization direction of the pump laser beam. This additional easy axis is the result of photo-induced adsorption of the cis isomer of the azo dye. An effective easy axis is the weighted average of the original easy axis and this new easy axis.

  14. Influence of the layer thickness and concentration of dye molecules on the emission amplification in cholesteric liquid crystals

    SciTech Connect

    Alaverdyan, R B; Gevorgyan, A A; Chilingaryan, A D; Chilingaryan, Yu S

    2008-05-31

    The propagation of light through a planar layer of a cholesteric liquid crystal doped with dye molecules is considered. The features of the emission spectra of the crystal are studied both in the absence and presence of dielectric boundaries. The increase in the emission intensity is investigated for different layer thicknesses and different concentrations of dye molecules. It is shown that an anomalously strong increase in the emission intensity with the diffraction intrinsic polarisation takes place in the case of a comparatively small crystal thickness and a relatively low concentration of dye molecules. The obtained results can be used for the development of miniature lasers with the circular polarisation of the fundamental radiation mode. (laser applications and other topics in quantum electronics)

  15. Optical phase conjugation in azo-dye doped chiral liquid crystal

    SciTech Connect

    Karpinski, Pawel; Miniewicz, Andrzej

    2012-10-15

    We report on optical phase conjugation phenomenon observed in chiral nematic liquid crystal showing band gap type Bragg reflection. The phase conjugate to the signal beam is observable only in the small temperature interval when the Bragg condition is fulfilled and only for circularly polarized light. The optical phase conjugation signals were observed at low cw laser light intensities (<100 mW/cm{sup 2}, {lambda} = 532 nm). Estimated value of third order optical susceptibility {chi}{sup (3)} = 2.8 Multiplication-Sign 10{sup -17} m{sup 2}/V{sup 2} is attributed to enhancement due to photoisomerisation of azo-dye (disperse red 1) inducing molecular reorientation process of liquid crystal molecules.

  16. Transition metal dithiolene complexes as near-IR dyes for liquid crystal device applications

    NASA Astrophysics Data System (ADS)

    Marshall, Kenneth L.; Schudel, Benjamin; Lippa, Irene A.

    2003-12-01

    Both commercial and military applications (e.g. free-space IR communications and sensor protection) exist for guest-host LC devices operating in the near-to mid IR region. Progress in this area has been hindered by the severe lack of near IR dyes with good solubility in the LC host, low impact on the inherent order of the LC phase, good thermal and chemical stability, and a large absorbance maximum tunable by structural modification over a broad range of the near IR region. Transition metal complexes based on nickel, palladium, or platinum dithiolene cores show substantial promise in meeting these requirements. These new dye complexes are extraordinarily stable, possess liquid crystalline phases in their own right with the proper terminal functional groups, and can have melting points below room temperature. The latter property is especially significant for producing liquid crystal/dye mixtures with both high dye concentration and good resistance to phase separation. Because they are zerovalent, they can exhibit high solubility in LC hosts (up to 10% wt%). The absorbance maximum in these materials can range from 600 nm to 1500 nm, depending on structure. With enantiomerically-enriched terminal substituents, nickel dithiolenes can induce a chiral mesophase in a non-chiral nematic host. This finding opens the possibility of generating novel LC mixtures with two degrees of tunability- an electronic absorbance band tunable by synthesis, and a selective reflection band tunable by temperature or applied electric field. Such a materials system would be particularly advantageous in sensor protection for dealing with frequency-agile laser threats.

  17. Security devices based on liquid crystals doped with a colour dye

    NASA Astrophysics Data System (ADS)

    Carrasco-Vela, C.; Quintana, X.; Otón, E.; Geday, M. A.; Otón, J. M.

    2011-12-01

    Liquid crystal properties make them useful for the development of security devices in applications of authentication and detection of fakes. Induced orientation of liquid crystal molecules and birefringence are the two main properties used in security devices. Employing liquid crystal and dichroic colorants, we have developed devices that show, with the aid of a polarizer, multiple images on each side of the device. Rubbed polyimide is used as alignment layer on each substrate of the LC cell. By rubbing the polyimide in different directions in each substrate it is possible to create any kind of symbols, drawings or motifs with a greyscale; the more complex the created device is, the more difficult is to fake it. To identify the motifs it is necessary to use polarized light. Depending on whether the polarizer is located in front of the LC cell or behind it, different motifs from one or the other substrate are shown. The effect arises from the dopant colour dye added to the liquid crystal, the induced orientation and the twist structure. In practice, a grazing reflection on a dielectric surface is polarized enough to see the effect. Any LC flat panel display can obviously be used as backlight as well.

  18. Biodecolorization and biodegradation potential of recalcitrant triphenylmethane dyes by Coriolopsis sp. isolated from compost.

    PubMed

    Chen, Si Hui; Yien Ting, Adeline Su

    2015-03-01

    Triphenylmethane dyes (TPM) are recalcitrant colorants brought into the environment. In this study, a lesser-known white rot fungus Coriolopsis sp. (1c3), isolated from compost of Empty Fruit Bunch (EFB) of oil palm, was explored for its decolorization potential of TPM dyes. The isolate 1c3 demonstrated good decolorization efficiencies in the treatment of Crystal Violet (CV; 100 mg l(-1)), Methyl Violet (MV; 100 mg l(-1)) and Cotton Blue (CB; 50 mg(-1)), with 94%, 97% and 91%, within 7, 7 and 1 day(s), respectively. Malachite Green (MG; 100 mg l(-1)) was the most recalcitrant dye, with 52% decolorization after 9 days. Dye removal by 1c3 was presumably via biosorption, whereby the process was determined to be influenced by fungal biomass, initial dye concentrations and oxygen requirements. Biodegradation was also a likely mechanism responsible for dye removal by 1c3, occurred as indicated by the reduction of dye spectra peaks. Detection of laccase, lignin peroxidase and NADH-DCIP reductase activities further substantiate the possible occurrence of biodegradation of TPM dyes by 1c3. PMID:25527986

  19. Triple dye plus rubbing alcohol versus triple dye alone for umbilical cord care.

    PubMed

    Suliman, Alawia K; Watts, Heidi; Beiler, Jessica; King, Tonya S; Khan, Sana; Carnuccio, Marybeth; Paul, Ian M

    2010-01-01

    Current practices for umbilical cord care vary across centers, but the evidence regarding these practices and their impact on cord separation, complications, and health care use are limited. The objective of this study was to compare the effect of triple dye alone (brilliant green, crystal violet, and proflavine hemisulfate) versus triple dye plus rubbing alcohol (isopropyl alcohol) twice daily on time to umbilical cord separation, complications, and health care use. For the 90 newborns who completed the study, there were no significant differences between treatment groups for time to cord separation, cord-related morbidities, or cord-related urgent care. Based on these study results, there does not appear to be significant benefit to the addition of twice daily applications of rubbing alcohol to neonatal umbilical cords following triple dye treatment after birth. PMID:20034947

  20. Modeling and characterization of dye-doped guest-host liquid crystal eyewear

    NASA Astrophysics Data System (ADS)

    Coutino, Pedro Coutino

    This thesis explores the use of dye-doped guest-host liquid crystals in variable transmission eyewear devices that protect against rapid and abrupt changes in lighting conditions. Some of their unique characteristics such as millisecond time response, low power consumption, fail-safe operation, and wide color palette make them the only available technology that meets the basic requirements for fast, adaptative eyewear applications. Despite these unique features, there are limitations in the technology which have hindered its use for more advanced eyewear applications. It is the aim of this dissertation to explore these limitations and provide experimental and numerical characterization tools necessary to surpass them. First, several techniques are described to evaluate materials and devices performance in terms of their photopic transmission, haze, birefringence, and distortion. The results are used to demonstrate that by choosing and combining the right materials, it is possible to improve the optical quality of the eyewear. Then, a simulation instrument which combines and integrates all the necessary elements to model the electro-optical response of dye-doped guest-host liquid crystal eyewear was constructed. This program is capable of reproducing with high accuracy experimental results, to predict the performance of devices, and to mimic the spectral curve of a target color. Numerical experiments were performed to study some of the most common limitations of the e-Tint mode or single cell technology including photopic transmission window, and polarization dependence and demonstrate that optimizing parameters such as birefringence, d/p, and concentration of dyes helps to overcome these limitations and enhance system performance. A guest-host double cell system is proposed as a new alternative mode for most advanced eyewear applications. Particular attention was placed on a switchable crossed polarizers configuration which offered superior optical characteristics

  1. Feedback-free single-beam pattern formation by nanosecond pulses in dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Lepeshkin, Nick N.; Lukishova, Svetlana G.; Boyd, Robert W.; Marshall, Kenneth L.

    2006-08-01

    Generally, optical feedback and/or two counter-propagating beams are necessary to form high-definition patterns in the cross section of a laser beam after passing through a nonlinear medium. In this paper we present an observation of pattern formation in liquid crystal media in a single laser beam without any external feedback. We found that after irradiation of a dye-doped liquid crystal cell with repetitive nanosecond pulses, the beam coming out of the liquid crystal cell exhibits a spectacular kaleidoscopic change of beam patterns in the far field. The patterns vary from pulse to pulse in an ordered manner cycling through a variety of complicated forms. We speculate that localized phase separation of the dye from the liquid crystal host occurs in the focal region of the beam in our experiments, and that the observed far-field patterns result from the laser-beam diffraction on these absorptive and refractive inhomogeneities.

  2. SORPTION AND TOXICITY OF AZO AND TRIPHENYLMETHANE DYES TO AQUATIC MICROBIAL POPULATIONS

    EPA Science Inventory

    Toxicity and sorption of five azo and triphenylmethane dyes to freshwater microbiota were determined to assessment, in part, the risks that these dyes may pose to the aquatic environment. The toxicities of Basic Violet 1, Basic Violet 2, Basic Violet 3, Basic Green 4 and Tropaeol...

  3. Random lasing in dye doped nematic liquid crystals: the role of confinement geometry

    NASA Astrophysics Data System (ADS)

    Strangi, G.; Ferjani, S.; Barna, V.; De Luca, A.; Versace, C.; Scaramuzza, N.; Bartolino, R.

    2007-05-01

    The first experimental evidence of random laser action in a partially ordered, dye doped nematic liquid crystal with long-range dielectric tensor fluctuations is reported. Above a given pump power the fluorescence curve collapses and discrete sharp peaks emerge above the residual spontaneous emission spectrum. The spectral linewidth of these emission peaks is narrow banded, typically around 0.5nm. The unexpected surviving of interference effects in recurrent multiple scattering of the emitted photons provide the required optical feedback for lasing in nematic liquid crystalline materials. Light waves coherent backscattering in orientationally ordered nematics manifests a weak localization, strongly supporting the diffusive laser action phenomenon in the presence of a gain medium. Unlike distributed feedback mirror-less laser, this system can be considered as a cavity-less microlaser where the disorder unexpectedly plays the most important role, behaving as randomly distributed feedback laser. The far field spatial distribution of the emission intensity shows a huge number of bright tiny spots spatially overlapped and the intensity of each pulse strongly fluctuates in time and space. Here, we report the main characteristics of this novel systems for various confinement geometries and under different conditions. A brief presentation of boundary-less systems such as free standing and freely suspended dye doped nematic films and droplets is also introduced, revealing unique emission features because of the complete absence of confining borders.

  4. Violet root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus causing violet root rot, Helicobasidium brebissonii (anamorph Rhizoctonia crocorum), is widely distributed in Europe and North America but is rarely of much economic importance on alfalfa. The disease has also been reported in Australia, Argentina, and Iran. The disease is characterized b...

  5. Behaviors of random laser in dye-doped nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Yao, Fengfeng; Bian, Huanting; Pei, Yanbo; Hou, Chunfeng; Sun, Xiudong

    2016-01-01

    Random lasing in the nematic liquid crystals (NLCs) with a high doping concentration of the laser dye was observed and characterized. With increasing the pump energy after the occurrence of the random laser (RL), the RL intensity first increases gradually to a maximum, then drops sharply to zero, accompanied by the gradual enhancement of scattering manifested by the growth of far-field diffraction rings of the transmitted pump beam in number. The threshold energy per unit pump area, slope efficiency, and maximal output intensity of the NLC RL depend heavily and nonmonotonically on the pump angle. A model involving the pump pulse induced molecular reorientation in NLCs leading to the pump angle dependent enhancement of scattering is proposed to explain the pump angle dependent properties of RLs.

  6. A random laser made of nematic liquid crystal doped with a laser dye

    NASA Astrophysics Data System (ADS)

    Sznitko, L.; Kaliciak, K.; Adamow, A.; Mysliwiec, J.

    2016-06-01

    We report on random laser emission obtained in 5CB and E7 nematic liquid crystal (LC) mixtures doped with 1% weight to weight ratio of DCM laser dye. The LC cell was used as asymmetric planar waveguide were emission was collected from the edge of the sample. Variable stripe length method was utilized to estimate the gain and the losses coefficients. Both systems have shown the threshold energy fluence in order of several mJ/cm2. In both cases above Fredericks potential, significant increase of emission intensity was observed due to the increase of light scattering on liquid crystalline domains. Moreover the use of fifth order of diffraction grating covered with thin alumina film resulted in strong multimode and directional laser emission.

  7. Effect of metal ions and redox mediators on decolorization of synthetic dyes by crude laccase from a novel white rot fungus Peniophora sp. (NFCCI-2131).

    PubMed

    Shankar, Shiv; Shikha; Nill, Shikha

    2015-01-01

    The effect of different metal ions and two redox mediators on laccase activity and laccase-catalyzed decolorization of five synthetic dyes was investigated in vitro using crude laccase from a novel white rot fungus Peniophora sp. (NFCCI-2131). The fungus effectively decolorized crystal violet and brilliant green on malt extract agar medium. Laccase activity was enhanced by metal ions such as Cd(2+), Mn(2+), Ni(2+), Co(2+), Na(+) Ca(2+), and Cu(2+). Among the different dyes tested, highest decolorization of crystal violet (96.30 %) was obtained in the presence of 1 mM ABTS followed by 86.01 % by HBT. The results conspicuously indicated that laccase from Peniophora sp. has the potential for color removal from textile dye effluent even in the presence of toxic metal ions. PMID:25293639

  8. Toxic textile dyes accumulate in wild European eel Anguilla anguilla.

    PubMed

    Belpaire, Claude; Reyns, Tim; Geeraerts, Caroline; Van Loco, Joris

    2015-11-01

    Dyes are used to stain inks, paints, textile, paper, leather and household products. They are omnipresent, some are toxic and may threaten our environment, especially aquatic ecosystems. The presence of residues of sixteen dyes (triarylmethanes, xanthenes, phenothiazines and phenoxazines) and their metabolites was analyzed in muscle tissue samples of individual yellow-phased European eels (Anguilla anguilla) from 91 locations in Belgian rivers, canals and lakes sampled between 2000 and 2009 using ultra performance liquid chromatography-tandem mass spectrometry. Eel was contaminated by dyes in 77% of the sites. Malachite Green, Crystal Violet and Brilliant Green were present in 25-58% of the samples. Dye occurrence was related to the distribution of textile and dye production industries. This field study is the first large-scale survey to document the occurrence of artificial dyes in wildlife. Considering the annual amounts of dyes produced worldwide and the unintentional spillage during their use, our observations warrant additional research in other parts of the world. The presence of these highly toxic dyes in the European eel may form an additional threat to this critically endangered species. The contaminated eels should be considered as not suitable for consumption. PMID:26291760

  9. Bistable light shutter using dye-doped liquid crystals for a see-through display

    NASA Astrophysics Data System (ADS)

    Huh, Jae-Won; Heo, Joon; Yu, Byeong-Huh; Yoon, Tae-Hoon

    2016-03-01

    See-through displays have got high attention as one of the next generation display devices. Especially, see-through displays that use organic light-emitting diodes (OLEDs) and liquid crystal displays (LCDs) have been actively studied. However, a see-through display using OLEDs cannot provide black color because of their see-through area. Although a see-through display using LCDs can provide black color with crossed polarizers, it cannot block the background. This inevitable problem can be solved by placing a light shutter at the back of a see-through display. To maintain the transparent or opaque state, an electric field must be applied to a light shutter. To achieve low power consumption, a bistable light shutter using polymer-stabilized cholesteric liquid crystals (CLC) has been proposed. It is switchable between the translucent and transparent states only. Therefore, it cannot provide black color. Moreover, it cannot block the background perfectly because of poor performance in the translucent state. In this work we will introduce a bistable light shutter using dye-doped CLCs. To improve the electro-optic characteristics in the opaque state, we employed a crossed electrode structure instead of a parallel one. We will demonstrate that the light shutter can exhibit stable bistable operation between the transparent homeotropic and opaque focal-conic states thanks to polymer stabilization.

  10. Adsorption of methyl violet from aqueous solutions by the biochars derived from crop residues.

    PubMed

    Xu, Ren-kou; Xiao, Shuang-cheng; Yuan, Jin-hua; Zhao, An-zhen

    2011-11-01

    The adsorption of methyl violet by the biochars from crop residues was investigated with batch and leaching experiments--adsorption capacity varied with their feedstock in the following order: canola straw char>peanut straw char>soybean straw char>rice hull char. This order was generally consistent with the amount of negative charge of the biochars. Zeta potentials and Fourier transform infrared photoacoustic spectroscopy, combined with adsorption isotherms and effect of ionic strength, indicated that adsorption of methyl violet on biochars involved electrostatic attraction, specific interaction between the dye and carboxylate and phenolic hydroxyl groups on the biochars, and surface precipitation. Leaching experiments showed that 156 g of rice hull char almost completely removed methyl violet from 18.2 L of water containing 1.0 mmol/L of methyl violet. The biochars had high removal efficiency for methyl violet and could be effective adsorbents for removal of methyl violet from wastewater. PMID:21924897

  11. Hierarchical Organization of Organic Dyes and Protein Cages into Photoactive Crystals.

    PubMed

    Mikkilä, Joona; Anaya-Plaza, Eduardo; Liljeström, Ville; Caston, Jose R; Torres, Tomas; Escosura, Andrés de la; Kostiainen, Mauri A

    2016-01-26

    Phthalocyanines (Pc) are non-natural organic dyes with wide and deep impact in materials science, based on their intense absorption at the near-infrared (NIR), long-lived fluorescence and high singlet oxygen ((1)O2) quantum yields. However, Pcs tend to stack in buffer solutions, losing their ability to generate singlet oxygen, which limits their scope of application. Furthermore, Pcs are challenging to organize in crystalline structures. Protein cages, on the other hand, are very promising biological building blocks that can be used to organize different materials into crystalline nanostructures. Here, we combine both kinds of components into photoactive biohybrid crystals. Toward this end, a hierarchical organization process has been designed in which (a) a supramolecular complex is formed between octacationic zinc Pc (1) and a tetraanionic pyrene (2) derivatives, driven by electrostatic and π-π interactions, and (b) the resulting tetracationic complex acts as a molecular glue that binds to the outer surface anionic patches of the apoferritin (aFt) protein cage, inducing cocrystallization. The obtained ternary face-centered cubic (fcc) packed cocrystals, with diameters up to 100 μm, retain the optical properties of the pristine dye molecules, such as fluorescence at 695 nm and efficient light-induced (1)O2 production. Considering that (1)O2 is utilized in important technologies such as photodynamic therapy (PDT), water treatments, diagnostic arrays and as an oxidant in organic synthesis, our results demonstrate a powerful methodology to create functional biohybrid systems with unprecedented long-range order. This approach should greatly aid the development of nanotechnology and biomedicine. PMID:26691783

  12. High flux and antifouling properties of negatively charged membrane for dyeing wastewater treatment by membrane distillation.

    PubMed

    An, Alicia Kyoungjin; Guo, Jiaxin; Jeong, Sanghyun; Lee, Eui-Jong; Tabatabai, S Assiyeh Alizadeh; Leiknes, TorOve

    2016-10-15

    This study investigated the applicability of membrane distillation (MD) to treat dyeing wastewater discharged by the textile industry. Four different dyes containing methylene blue (MB), crystal violet (CV), acid red 18 (AR18), and acid yellow 36 (AY36) were tested. Two types of hydrophobic membranes made of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) were used. The membranes were characterized by testing against each dye (foulant-foulant) and the membrane-dye (membrane-foulant) interfacial interactions and their mechanisms were identified. The MD membranes possessed negative charges, which facilitated the treatment of acid and azo dyes of the same charge and showed higher fluxes. In addition, PTFE membrane reduced the wettability with higher hydrophobicity of the membrane surface. The PTFE membrane evidenced especially its resistant to dye absorption, as its strong negative charge and chemical structure caused a flake-like (loose) dye-dye structure to form on the membrane surface rather than in the membrane pores. This also enabled the recovery of flux and membrane properties by water flushing (WF), thereby direct-contact MD with PTFE membrane treating 100 mg/L of dye mixtures showed stable flux and superior color removal during five days operation. Thus, MD shows a potential for stable long-term operation in conjunction with a simple membrane cleaning process, and its suitability in dyeing wastewater treatment. PMID:27486044

  13. Spectral plasmonic effect in the nano-cavity of dye-doped nanosphere-based photonic crystals.

    PubMed

    Yadav, Ashish; Danesh, Mohammad; Zhong, Liubiao; Cheng, Gary J; Jiang, Lin; Chi, Lifeng

    2016-04-22

    We demonstrated three-dimensional PMMA-based photonic crystal (3D-PC) nanostructures attached to Au nanoparticles (AuNPs), which undergo self-organization into super lattice planes and enhance the fluorescence properties. This new structure exhibited interesting tunable spectral, peak broadening plasmonic behavior because of strong plasmonic interaction at high laser powers. The presented work provides an important tool to improve the efficiency of dye laser applications. PMID:26954366

  14. Spectral plasmonic effect in the nano-cavity of dye-doped nanosphere-based photonic crystals

    NASA Astrophysics Data System (ADS)

    Yadav, Ashish; Danesh, Mohammad; Zhong, Liubiao; Cheng, Gary J.; Jiang, Lin; Chi, Lifeng

    2016-04-01

    We demonstrated three-dimensional PMMA-based photonic crystal (3D-PC) nanostructures attached to Au nanoparticles (AuNPs), which undergo self-organization into super lattice planes and enhance the fluorescence properties. This new structure exhibited interesting tunable spectral, peak broadening plasmonic behavior because of strong plasmonic interaction at high laser powers. The presented work provides an important tool to improve the efficiency of dye laser applications.

  15. Laser kinetic processes in dye mixtures

    SciTech Connect

    Lei Jie; Fu Honglang

    1988-11-01

    Radiation from rhodamine 6G+cresyl violet and rhodamine B+cresyl violet dye mixtures in ethyl alcohol pumped by N/sub 2/ laser light were studied. The rate constants of resonant transfer in the mixtures were determined. The radiative transfer processes are discussed.

  16. Rapid degradation of dyes in water by magnetic Fe(0)/Fe3O4/graphene composites.

    PubMed

    Chong, Shan; Zhang, Guangming; Tian, Huifang; Zhao, He

    2016-06-01

    Magnetic Fe(0)/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption-desorption, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), vibrating-sample magnetometer (VSM) measurements and X-ray photoelectron spectroscopy (XPS). The results indicated that Fe(0)/Fe3O4/graphene had a layered structure with Fe crystals highly dispersed in the interlayers of graphene, which could enhance the mass transfer process between Fe(0)/Fe3O4/graphene and pollutants. Fe(0)/Fe3O4/graphene exhibited ferromagnetism and could be easily separated and re-dispersed for reuse in water. Typical dyes, such as Methyl Orange, Methylene Blue and Crystal Violet, could be decolorized by Fe(0)/Fe3O4/graphene rapidly. After 20min, the decolorization efficiencies of methyl orange, methylene blue and crystal violet were 94.78%, 91.60% and 89.07%, respectively. The reaction mechanism of Fe(0)/Fe3O4/graphene with dyes mainly included adsorption and enhanced reduction by the composite. Thus, Fe(0)/Fe3O4/graphene prepared by the one-step reduction method has excellent performance in removal of dyes in water. PMID:27266311

  17. A New Organic Dye-Based Staining for The Detection of Plant DNA in Agarose Gels.

    PubMed

    Sönmezoğlu, Özlem Ateş; Özkay, Kerime

    2015-01-01

    Ethidium bromide (EtBr) is used to stain DNA in agarose gel electrophoresis, but this dye is mutagenic and carcinogenic. We investigated N-719, which is a visible, reliable and organic Ruthenium-based dye, and five fluorescent alternatives for staining plant DNA. For prestaining and poststaining, N-719, GelRed, and SYBR Safe stained both DNA and PCR product bands as clearly as EtBr. SYBR Green I, methylene blue, and crystal violet were effective for poststaining only. The organic dye N-719 stained DNA bands as sensitively and as clearly as EtBr. Consequently, organic dyes can be used as alternatives to EtBr in plant biotechnology studies. PMID:26158569

  18. Synthesis, Structure, and Properties of the Fullerene C60 Salt of Crystal Violet, (CV(+) )(C60 (.-) )⋅0.5 C6 H4 Cl2 , which Contained Closely Packed Zigzagged C60 (.-) Chains.

    PubMed

    Konarev, Dmitri V; Kuzmin, Alexey V; Khasanov, Salavat S; Ishikawa, Manabu; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

    2016-06-01

    The reduction of fullerene C60 by zinc dust in the presence of crystal violet cations (CV(+) ) yielded a deep-blue solution, from which crystals of (CV(+) )(C60 (.-) )⋅0.5 C6 H4 Cl2 (1) were obtained by slow mixing with n-hexane. The salt contained isolated, closely packed zigzagged chains that were composed of C60 (.-) radical anions with a uniform interfullerene center-to-center distance of 9.98 Å. In spite of the close proximity of the fullerenes, they did not dimerize, owing to spatial separation by the phenyl substituents of CV(+) . The room-temperature conductivity of compound 1 was 3×10(-2)  S cm(-1) along the fullerene chains. The salt exhibited semiconducting behavior, with an activation energy of Ea =167 meV. Spins localized on C60 (.-) were antiferromagnetically coupled within the fullerene chains, with a Weiss temperature of -19 K without long-range magnetic ordering down to 1.9 K. PMID:27062654

  19. 27 CFR 21.111 - Gentian violet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....111 Gentian violet. (a) Gentian violet (methyl violet, methylrosaniline chloride) occurs as a dark.... (d) Insoluble matter. Not to exceed 0.25 percent when tested by the following method: Transfer...

  20. 27 CFR 21.111 - Gentian violet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....111 Gentian violet. (a) Gentian violet (methyl violet, methylrosaniline chloride) occurs as a dark.... (d) Insoluble matter. Not to exceed 0.25 percent when tested by the following method: Transfer...

  1. 27 CFR 21.111 - Gentian violet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....111 Gentian violet. (a) Gentian violet (methyl violet, methylrosaniline chloride) occurs as a dark.... (d) Insoluble matter. Not to exceed 0.25 percent when tested by the following method: Transfer...

  2. 27 CFR 21.111 - Gentian violet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....111 Gentian violet. (a) Gentian violet (methyl violet, methylrosaniline chloride) occurs as a dark.... (d) Insoluble matter. Not to exceed 0.25 percent when tested by the following method: Transfer...

  3. Two-photon absorption in Hg 2Cl 2 crystals

    NASA Astrophysics Data System (ADS)

    Pelant, I.; Ambrož, M.; Hála, J.; Kohlová, V.; Barta, Č.

    1985-01-01

    Violet luminescence (396 nm) of Hg 2Cl 2 single crystals was observed under excitation of green light (∼ 500 nm) of a pulsed dye laser at liquid helium temperature. The effect is interpreted as due to the two-photon absorption process. The two-photon excitation spectrum of the luminescence was measured in the wavelength range 475-530 nm. Possible mechanisms of the two-photon transition are outlined.

  4. Laser dye technology

    SciTech Connect

    Hammond, P R

    1999-09-01

    The author has worked with laser dyes for a number of years. A first interest was in the Navy blue-green program where a flashlamp pumped dye laser was used as an underwater communication and detection device. It made use of the optical window of sea-water--blue for deep ocean, green for coastal water. A major activity however has been with the Atomic Vapor Laser Isotope Separation Program (AVLIS) at the Lawrence Livermore National Laboratory. The aim here has been enriching isotopes for the nuclear fuel cycle. The tunability of the dye laser is utilized to selectively excite one isotope in uranium vapor, and this isotope is collected electrostatically as shown in Figure 1. The interests in the AVLIS program have been in the near ultra-violet, violet, red and deep-red.

  5. Dye-sensitized nanoarrays with discotic liquid crystals as interlayer for high-efficiency inverted polymer solar cells.

    PubMed

    Shi, Yueqin; Tan, Licheng; Chen, Yiwang

    2014-10-22

    The well-aligned and highly uniform one-dimensional ZnO with organic dyes core/shell (ZNs) and ZnO with dyes and liquid crystals core/double-shells nanoarrays (ZNLs) with controllable lengths were fabricated as electron transport layers (ETLs) in inverted polymer solar cells (PSCs). Ditetrabutylammonium cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium(II) dye (N719) was presented to reduce the surface defects of ZnO nanoarrays (NAs). In addition, the shell modification could decrease the electron injection barrier between ZnO and active layer, thereby facilitating electron injection effectively and forming a direct electron transport channel into the cathode. Due to the orientation of nanoarrays and the self-organization of 3,6,7,10,11-pentakis(hexyloxy)-2-hydroxytriphenylene liquid crystals (LCs) in liquid crystalline mesophase and isotropic phase transition, the components of active layer would be driven rearrange and infiltrate among the interspaces of nanoarrays more orderly. The increased interfacial contact between cathode and active layer would benefit charge generation, transportation and collection. On the basis of these advantages, it was found the N719 shell and N719/LCs double-shells modifications of ZnO NAs could boost the photovoltaic performance of PSCs with the best power conversion efficiency (PCE) of 7.3% and 8.0%, respectively. PMID:25269148

  6. Self-Assembly and Formation of Chromonic Liquid Crystals from the Dyes Quinaldine Red Acetate and Pyronin Y.

    PubMed

    Magana, J R; Homs, M; Solans, C; Obiols-Rabasa, M; Salonen, L M; Rodríguez-Abreu, C

    2016-01-14

    The aqueous self-assembly behavior of the dyes Quinaldine red acetate and Pyronin Y in a wide range of concentrations is reported here for the first time. (1)H NMR spectroscopy, polarized-light optical microscopy, and small and wide X-ray scattering were used to get insight into molecular interactions, phase boundaries and aggregate structure. Quinaldine red acetate and Pyronin Y self-organize into unimolecular stacks driven by attractive aromatic interactions. At high concentrations, spatial correlation among the molecular stacks gives rise to nematic liquid crystals in both systems. Quinaldine red acetate additionally produces a rare chromonic O phase built of columnar aggregates with anisotropic cross-section ordered in a rectangular lattice. The O phase changes into a columnar lamellar structure as a result of a temperature-induced phase transition. Results open the possibility of finding chromonic liquid crystals in other commercially available dyes with a similar molecular structure. This would eventually expand the availability of these unique soft materials and thus introduce new applications for marketed dyes. PMID:26700729

  7. Synthesis and analysis of nickel dithiolene dyes in a nematic liquid crystal host. 1998 summer research program for high school juniors at the University of Rochester`s Laboratory for Laser Energetics: Student research reports

    SciTech Connect

    Lippa, I.

    1999-03-01

    The Liquid Crystal Point Diffraction Interferometer (LCPDI) can be employed to evaluate the Omega Laser system for optimum firing capabilities. This device utilizes a nickel dithiolene infrared absorbing liquid crystal dye dissolved in a liquid crystal host medium (Merck E7). Three nickel dithiolene dyes were characterized for both their solubility in the E7 host and their infrared spectral absorption.

  8. Experimental and molecular dynamics studies of anthraquinone dyes in a nematic liquid-crystal host: a rationale for observed alignment trends.

    PubMed

    Sims, Mark T; Abbott, Laurence C; Cowling, Stephen J; Goodby, John W; Moore, John N

    2016-07-27

    Five anthraquinone dyes with bis(4-propylphenyl) substituents, connected via sulfide or amine linking groups at the 1,5-positions or directly at the 2,6-positions, have been studied as guests in the nematic liquid crystal host, E7. Polarized UV-visible absorption spectra of aligned samples were used to obtain experimental dichroic order parameters, which exhibit values in the range 0.51-0.74. Fully atomistic MD simulations of these guest-host systems were carried out, generally using default parameters but using new force constants derived here for the dyes containing flexible phenyl-sulfide and phenyl-amine linking groups. An analysis of the alignment of the dye molecules in these simulations provides calculated molecular order parameters, which are combined with calculated order parameters for the alignment of the transition dipole moments within the dyes, reported previously, to give calculated dichroic order parameters. The trend in the calculated dichroic order parameters between the dyes shows a good match with the trend in the experimental values, enabling the observed variation to be rationalised primarily by changes in the alignment of the calculated transition dipole moments within the dyes; the calculated molecular order parameters show a relatively small variation between the dyes. The results indicate that this computational approach may be used generally to rationalise trends in the alignment of guest molecules in liquid crystal hosts, suggesting that it may also be able to provide a predictive aid in the design of guest dyes. PMID:27411959

  9. Far-Field Patterns from Dye-Doped Planar-Aligned Nematic Liquid Crystals Under nanosecond Laser Irradiation

    SciTech Connect

    Lukishova, S.G.; Lepeshkin, N.; Boyd, R.W.; Marshall, K.L.

    2006-08-18

    High-definition patterns were observed under 10-Hz-pulse-repetition-rate, nanosecond laser irradiation of azodye-doped planar-nematic liquid crystal layers at incident intensities I ~ 5-10 MW/cm^2 in a single beam configuration and without any feedback involved. An incident polarization parallel to the nematic director was used. Under periodic pulsed laser irradiation, far-field beam patterns at the output of a dye-doped liquid crystal layer changed kaleidoscopically from rings and stripes to multiple hexagons. This pattern-formation regime had a buildup time of several seconds to minutes. We explain the observed effect by diffraction of the laser beam on light-induced micrometer-size inhomogeneities inside the liquid crystal layer with absorption and refraction properties different from the surrounding area. Possible mechanisms of the formation of the inhomogeneities are discussed.

  10. Final report on the safety assessment of Acid Violet 43.

    PubMed

    Fiume, M Z

    2001-01-01

    Acid Violet 43 is an anthraquinone color that may be used as a colorant in cosmetic formulations that are hair dyes, colors, and coloring rinses. Batches of Acid Violet 43 that are certified to meet the United States Food and Drug Administration (U.S. FDA) specifications are termed Ext. D & C Violet No. 2. Hair dyes and colors containing Acid Violet 43 are considered coal tar ingredients and, as such, routinely bear a caution statement regarding potential skin irritation and instructions for determining whether the product causes skin irritation in any given individual. Expected concentrations of use are less than or equal to 1%. Impurities include anthracenedione derivatives, p-toluidine, and p-toluidine sulfonic acid, as well as heavy metals. Based on extensive safety test data, the U.S. FDA has established specifications (including limits on impurities) for Ext. D & C Violet No. 2 that allow its use in any cosmetic. It is the certified color (Ext. D & C Violet No. 2) that has been evaluated in the following safety tests. Oral toxicity tests do not demonstrate significant acute toxicity. In a short-term dermal toxicity study using guinea pigs and a subchronic dermal toxicity study using rabbits, no signs of systemic toxicity and no significant local skin reactions were noted. This ingredient was not genotoxic in bacterial assays, nor was it carcinogenic when applied to mouse skin at a 1% concentration. Accordingly, Acid Violet 43 was determined to be safe for use in hair dye formulations, when impurities are limited as follows: < or = 18% volatile matter (at 135 degrees C) and chlorides and sulfates (calculated as sodium salts); < or = 0.4% water-insoluble matter; < or = 0.2% 1-hydroxy-9,10-anthracenedione; < or = 0.2% 1,4-dihydroxy-9,10-anthracenedione; < or = 0.1% p-toluidine; < or = 0.2% p-toluidine sulfonic acids, sodium salts; < or = 1% subsidiary colors; < or = 20 ppm lead (as Pb); < or = 3 ppm arsenic (as As); < or = 1 ppm mercury (as Hg); and with > or

  11. Biological removal of triphenylmethane dyes from aqueous solution by Lemna minor.

    PubMed

    Török, Anamaria; Buta, Erzsébet; Indolean, Cerasella; Tonk, Szende; Silaghi-Dumitrescu, Luminita; Majdik, Cornelia

    2015-01-01

    The aim of this study is to investigate and develop a phytoremediation method for the removal of two triphenylmethane dyes (crystal violet and malachite green) using an aquatic plant, Lemna minor. The effects of operational parameters such as aquatic plant quantity, initial dye concentration, initial pH of the solutions and temperature of the medium were studied in order to determine the optimum phytoremediation conditions. The plant's photosynthetic pigments were determined quantitatively in order to detect the plant's response to abiotic stress. During the phytoremediation experiments the parallel sub-processes (phytosorption, phytoextraction, phytodegradation) were observed and analysed. The mechanisms of phytoremediation were studied using Fourier transformation infrared spectroscopy, ultraviolet-visible spectroscopy, thin layer chromatography and Energy-dispersive X-ray spectroscopy. Results show that the plant tolerated high concentrations (300 mg/L) of dyes, and was able to remove from the environment and accumulate in its cells the dyes up to a significant percentage (crystal violet was removed by about 80% and malachite green by 90%). PMID:26085430

  12. Plant-mediated synthesis of silver-nanocomposite as novel effective azo dye adsorbent

    NASA Astrophysics Data System (ADS)

    Satapathy, Mantosh Kumar; Banerjee, Priya; Das, Papita

    2015-01-01

    Toxicity of textile effluent is a globally alarming issue nowadays. In order to address this problem, a cost-effective and environment-friendly technique for adsorption of toxic dyes has been introduced in this research. Firstly in this study, green synthesis of silver nanoparticles (AgNPs) having antibacterial efficacy, had been carried out using leaf extracts of Azadirachta indica as reducing as well as capping agent. This research idea was further extended for the development and application of a novel method of preparation of silver-nanocomposite using synthesized microwave-assisted AgNPs with soil as a novel nanocomposite to adsorb hazardous dyes. However, this nanocomposite was found to possess higher efficiency and adsorption capacity in comparison to soil as adsorbent for the removal of crystal violet dye under same experimental conditions. Additionally, it was also observed that use of this Ag-nanocomposite as adsorbent helped in achieving about 97.2 % removal of crystal violet dye from the effluent solution.

  13. Dynamic polarization grating based on a dye-doped liquid crystal controllable by a single beam in a homeotropic-planar geometry.

    PubMed

    Kim, Hak-Rin; Jang, Eunje; Kim, Jiyoon; Joo, Kyung-Il; Lee, Sin-Doo

    2012-12-20

    We present a dynamic polarization grating based on a dye-doped liquid crystal cell that is controllable by a single pump beam in a binary homeotropic-planar configuration produced through selective rubbing. Upon single pump beam irradiation, the azo dyes in the liquid-crystal (LC) layer diffuse and adsorb onto the planar LC-anchoring surface due to trans-cis photo-isomerization. It is found that the dynamic polarization grating effect results mainly from the photo-induced easy axis reorientation by the amount of dye molecules adsorbed on the planar LC-alignment surface in a single-beam control scheme. The initial LC-anchoring conditions and the dynamic behavior of the dye adsorption strongly influence the repetitive writing-erasing processes by the single pump beam. PMID:23262590

  14. A chemometric-assisted method for the simultaneous determination of malachite green and crystal violet in water based on absorbance-pH data generated by a homemade pH gradient apparatus.

    PubMed

    Yu, Shuling; Yuan, Xuejie; Yang, Jing; Yuan, Jintao; Shi, Jiahua; Wang, Yali; Chen, Yuewen; Gao, Shufang

    2015-01-01

    An attractive method of generating second-order data was developed by a dropping technique to generate pH gradient simultaneously coupled with diode-array spectrophotometer scanning. A homemade apparatus designed for the pH gradient. The method and the homemade apparatus were used to simultaneously determine malachite green (MG) and crystal violet (CV) in water samples. The absorbance-pH second-order data of MG or CV were obtained from the spectra of MG or CV in a series of pH values of HCl-KCl solution. The second-order data of mixtures containing MG and CV that coexisted with interferents were analyzed using multidimensional partial least-squares with residual bilinearization. The method and homemade apparatus were used to simultaneously determine MG and CV in fish farming water samples and in river ones with satisfactory results. The presented method and the homemade apparatus could serve as an alternative tool to handle some analysis problems. PMID:26057094

  15. 21 CFR 73.3107 - Carbazole violet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Carbazole violet. 73.3107 Section 73.3107 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3107 Carbazole violet. (a) Identity. The color additive is carbazole violet (Pigment Violet 23) (CAS Reg. No. 6358-30-1, Colour Index No. 51319). (b)...

  16. Photoalignment control: self-focusing effect in hybrid- and homeotropic-aligned dye-doped polymer-stabilized liquid crystals

    NASA Astrophysics Data System (ADS)

    Wang, J.; Shishido, A.

    2015-09-01

    Nonlinear optics has drawn much attention for its great potential in applications, such as frequency conversion, multiple-photon absorption, self-focusing, and so on. However, such optical nonlinearities are generally observed at very high light intensities. In this study, we designed hybrid-aligned dye-doped polymer-stabilized liquid crystals (PSLC), in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. In such film, the threshold intensity required to form self-focusing effect was markedly reduced by a factor of 8.5 compared to that in a conventional homeotropic cell, which enabled the generation of the self-focusing effect using a handheld 1-mW laser pointer. In addition, we investigated the structural effect of dye molecules: azo-dye methyl red (MR, photoisomerizable)-doped PSLC was prepared and its NLO response was evaluated. It turned out that such MR-based LC system was not effective for self-focusing effect compared to oligothiophene-doped systems.

  17. Specific features of the crystal packing that enable styryl dyes of the pyridine series to undergo the solid-phase [2 + 2] photocycloaddition including the process with single crystal retention

    SciTech Connect

    Kuz'mina, L. G.; Vedernikov, A. I.; Sazonov, S. K.; Lobova, N. A.; Loginov, P. S.; Howard, J. A. K.; Alfimov, M. V.; Gromov, S. P.

    2008-05-15

    The crystal packing of a number of styryl dyes of the pyridine series is analyzed. The structures of three dyes and three [2 + 2] photocycloaddition (PCA) products, 1,2,3,4-tetrasubstituted cyclobutanes, obtained in single crystals are determined by X-ray diffraction. Stacks of planar organic cations are characteristic of styryl dye packings. The proceeding of the PCA reaction as a single crystal-to-single crystal transformation in the syn head-to-head stacks is in principle impossible. The syn head-to-tail stacking packings are favorable for the PCA reactions resulting in the centrosymmetric rctt isomers of cyclobutane. The stacking packings, in which molecules are related by the twofold axes (the anti arrangement of molecules), are also favorable for PCA in single crystals. In this case, the products are the rtct isomers of cyclobutane. The presence of the I{sup -} counterions in a packing is a factor impeding the PCA reaction, because the secondary I-H-C bonds increase the rigidity of the crystal lattice. The conditions necessary for proceeding the PCA reactions in styryl dyes as single crystal-to-single crystal processes are as follows: (1) the stacks split into pairs of organic cations (dimers) with the d distances within 4.2 A in a dimer and d exceeding 4.2 A between the dimers; and (2) the dimers are surrounded by flexible shells consisting of anions, solvate molecules, or flexible moieties of the organic cations themselves.

  18. Electrically controllable plasmonic enhanced coherent random lasing from dye-doped nematic liquid crystals containing Au nanoparticles.

    PubMed

    Wang, Lei; Wan, Yuan; Shi, Lijie; Zhong, Haizheng; Deng, Luogen

    2016-08-01

    An electrically controllable plasmonic enhanced coherent random lasing from the dye-doped nematic liquid crystal containing Au nanoparticles is demonstrated. To achieve the optimal control of the RL properties, the polarization of the pump light should be parallel to the rubbing direction of the cells. The lasing output intensity is direction-dependent and the substantial output distributes in an angle range of 0°~30° deviating from the direction of the pump stripe. The coherent feedback associated with the coherent random lasing mainly originates from the cooperative effect of the enhanced localized electric field in the vicinity of Au nanoparticles and the multiple scattering caused by the fluctuations of the liquid crystal director and local dielectric tensor. PMID:27505729

  19. Surface-enhanced resonance hyper-Raman scattering and surface-enhanced resonance Raman scattering of dyes adsorbed on silver electrode and silver colloid: a comparison study

    NASA Astrophysics Data System (ADS)

    Li, Wu-Hu; Li, Xiao-Yuan; Yu, Nai-Teng

    1999-10-01

    Surface-enhanced resonance hyper-Raman scattering (SERHRS) and surface-enhanced resonance Raman scattering (SERRS) of three dyes, rhodamine 6G, crystal violet and basic fuchsin, are studied comparatively on electrochemically roughened silver electrode and silver colloid, respectively. All three dyes show a better SERHRS efficiency on the silver colloid than on the silver electrode, a phenomenon just opposite to what we have recently observed for pyridine and pyrazine [Chem. Phys. Lett. 305 (1999) 303]. These results suggest that the efficiency of SEHRS depends not only on the active surfaces employed (colloidal metals versus roughened electrodes) but also on the types of the adsorbed molecules.

  20. Polyamide as an efficient sorbent for simultaneous interface-free determination of three Sudan dyes in saffron and urine using high-performance liquid chromatography-ultra violet detection.

    PubMed

    Saeidi, Iman; Barfi, Behruz; Payrovi, Moazameh; Feizy, Javid; Sheibani, Hojat A; Miri, Mina; Ghollasi Moud, Farahnaz

    2015-01-01

    With polyamide (PA) as an efficient sorbent for solid phase extraction (SPE) of Sudan dyes II, III and Red 7B from saffron and urine, their determination by HPLC was performed. The optimum conditions for SPE were achieved using 7 mL methanol/water (1:9, v/v, pH 7) as the washing solvent and 3 mL tetrahydrofuran for elution. Good clean-up and high (above 90%) recoveries were observed for all the analytes. The optimized mobile phase composition for HPLC analysis of these compounds was methanol-water (70:30, v/v). The SPE parameters, such as the maximum loading capacity and breakthrough volume, were also determined for each analyte. The limits of detection (LODs), limits of quantification (LOQs), linear ranges and recoveries for the analytes were 4.6-6.6 microg/L, 13.0-19.8 microg/L, 13.0-5000 microg/L (r2>0.99) and 92.5%-113.4%, respectively. The precisions (RSDs) of the overall analytical procedure, estimated by five replicate measurements for Sudan II, III and Red 7B in saffron and urine samples were 2.3%, 1.8% and 3.6%, respectively. The developed method is simple and successful in the application to the determination of Sudan dyes in saffron and urine samples with HPLC coupled with UV detection. PMID:25958664

  1. Plasma-Assisted Synthesis of High-Mobility Atomically Layered Violet Phosphorus.

    PubMed

    Tsai, Hsu-Sheng; Lai, Chih-Chung; Hsiao, Ching-Hung; Medina, Henry; Su, Teng-Yu; Ouyang, Hao; Chen, Tai-Hsiang; Liang, Jenq-Horng; Chueh, Yu-Lun

    2015-07-01

    Two-dimensional layered materials such as graphene, transition metal dichalcogenides, and black phosphorus have demonstrated outstanding properties due to electron confinement as the thickness is reduced to atomic scale. Among the phosphorus allotropes, black phosphorus, and violet phosphorus possess layer structure with the potential to be scaled down to atomically thin film. For the first time, the plasma-assisted synthesis of atomically layered violet phosphorus has been achieved. Material characterization supports the formation of violet phosphorus/InN over InP substrate where the layer structure of violet phosphorus is clearly observed. The identification of the crystal structure and lattice constant ratifies the formation of violet phosphorus indeed. The critical concept of this synthesis method is the selective reaction induced by different variations of Gibbs free energy (ΔG) of reactions. Besides, the Hall mobility of the violet phosphorus on the InP substrate greatly increases over the theoretical values of InP bulk material without much reduction in the carrier concentration, suggesting that the mobility enhancement results from the violet phosphorus layers. Furthermore, this study demonstrates a low-cost technique with high compatibility to synthesize the high-mobility atomically layered violet phosphorus and open the space for the study of the fundamental properties of this intriguing material as a new member of the fast growing family of 2D crystals. PMID:26070035

  2. Rapid Charge Transport in Dye-Sensitized Solar Cells Made from Vertically Aligned Single-Crystal Rutile TiO2 Nanowires

    SciTech Connect

    Feng, X.; Zhu, K.; Frank, A. J.; Grimes, C. A.; Mallouk, T. E.

    2012-03-12

    A rapid solvothermal approach was used to synthesize aligned 1D single-crystal rutile TiO2 nanowire (NW) arrays on transparent conducting substrates as electrodes for dye-sensitized solar cells. The NW arrays showed a more than 200 times faster charge transport (see picture) and a factor four lower defect state density than conventional rutile nanoparticle films.

  3. Feulgen type staining with Hoffmann's violet-SO2 under exposure to UV rays.

    PubMed

    Dutt, M K

    1979-07-01

    The paper contains an account of the use of Hoffmann's violet-SO2 under exposure to UV rays during staining acid-hydrolysed DNA of mammalian tissue nuclei. Preparations stained with Hoffmann's violet-SO2 without exposure to UV rays reveal extremely pale violet nuclei but when stained under the influence of UV rays show a considerably faster reaction resulting in a very much deeper staining of the nuclei. Sections after staining with this dye-reagent require n-butanol as differentiating reagent. Possible interpretation for the increase in staining ability of this dye-reagent under exposure to UV rays has been elucidated and the reason for considering the reaction as Feulgen type has been discussed. PMID:91084

  4. Platinum-scatterer-based random lasers from dye-doped polymer-dispersed liquid crystals in capillary tubes.

    PubMed

    Wang, Jianlong; Zhang, Yating; Cao, Mingxuan; Song, Xiaoxian; Che, Yongli; Zhang, Haiting; Zhang, Heng; Yao, Jianquan

    2016-07-20

    The resonance characteristics of platinum-scatter-based random lasers from dye-doped polymer-dispersed liquid crystals (DDPDLCs) in capillary tubes were researched for the first time, to the best of our knowledge. After adding platinum nanoparticles (Pt NPs) into the liquid crystal mixtures, the emission spectra of DDPDLCs revealed a lower lasing threshold in comparison with those of DDPDLCs without Pt NPs due to light scattering of liquid crystal droplets and the local field enhancement around Pt NPs. Furthermore, the full width at half-maximum (FWHM) and the lasing threshold were determined by the doping density of the Pt NPs. The threshold was decreased by about half from 17.5  μJ/pulse to 8.7  μJ/pulse on the condition that around 1.0 wt. % was the optimum concentration of Pt NPs doped into the DDPDLCs. The FWHM of the peaks sharply decreased to 0.1 nm. Our work provides an extremely simple method to enhance random lasers from DDPDLCs doped with Pt NPs, and it has potential applications in random fiber lasers or laser displays. PMID:27463926

  5. Characterization of a liquid crystal/dye cell for a future application in display-integrated photovoltaics

    NASA Astrophysics Data System (ADS)

    Fujieda, Ichiro; Itaya, Shunsuke; Ohta, Masamichi; Ozawa, Shintaro; Azmi, Nada Dianah Binti M.

    2016-04-01

    One can convert a luminescent solar concentrator to a display by scanning a laser beam on it. When a guest-host system of liquid crystal (LC) and dye materials are incorporated, absorption of excitation light and the radiation pattern of photoluminescence (PL) can be adjusted to changes in lighting condition. The resolution of a displayed image can be degraded by PL spreading in the LC/dye layer. Its contrast can be limited by the PL induced by ambient light. In the experiment, we fabricated a 22×25 mm2 cell that contained 0.5 wt. % coumarin 6 in a nematic LC host. The alignment was antiparallel and the gap was 6 μm. Using a blue laser beam of 0.04 mm FWHM, the PL intensity distribution was measured to be 0.20 mm FWHM at zero bias. It became slightly wider at 10 V. For contrast evaluation, we measured PL spectra under two conditions. First, the center of the cell was irradiated by a 1.7-mW blue laser beam. Second, the whole cell was uniformly exposed to light from a fluorescent lamp at illuminance of 800lx. The contrast of luminance was calculated to be 1.4×105. The optical power reaching its edge surfaces was measured and roughly agreed with the prediction by a simple model.

  6. Effective removal of cationic dyes using carboxylate-functionalized cellulose nanocrystals.

    PubMed

    Qiao, Han; Zhou, Yanmei; Yu, Fang; Wang, Enze; Min, Yinghao; Huang, Qi; Pang, Lanfang; Ma, Tongsen

    2015-12-01

    A novel carboxylate-functionalized adsorbent (CNM) based on cellulose nanocrystals (CNCs) was prepared and adsorptive removal of multiple cationic dyes (crystal violet, methylene blue, malachite green and basic fuchsin) were investigated. The maximum cationic dyes uptakes ranged from 30.0 to 348.9mgg(-1) following the order of: CNM>CNCs>raw cellulose. Furthermore, the removal of crystal violet by CNM was investigated representatively where kinetics, thermodynamics and isotherm analysis were employed to explain in-depth information associated with the adsorption process. The adsorption kinetics fitted well to the pseudo-second-order model and thermodynamic analysis revealed that the adsorption process was spontaneous and exothermic. Meanwhile, isothermal study demonstrated a monolayer adsorption behavior following the Langmuir model with a calculated maximum absorption capacity of 243.9mgg(-1), which is higher than those of many other reported adsorbents. These findings prefigure the promising potentials of CNM as a versatile adsorbent for the efficient removal of cationic dyes from wastewater. PMID:26298027

  7. Enhanced optical, dielectric and piezoelectric behavior in dye doped zinc tris-thiourea sulphate (ZTS) single crystals

    NASA Astrophysics Data System (ADS)

    Bhandari, Sonia; Sinha, Nidhi; Ray, Geeta; Kumar, Binay

    2014-01-01

    Pure and 0.1 mol% amaranth dye doped zinc tris-thiourea sulphate (ZTS) crystals were grown by slow evaporation technique. Orthorhombic structures with changed morphology were observed. Various functional groups present were identified by FTIR and Raman analysis. UV-Vis spectra shows wide transmittance and increased optical band gap from 4.54 to 4.59 eV, with lower extinction coefficient in doped case. In photoluminescence measurement, an intense peak at 416 nm was observed for doped ZTS. Dielectric constant value increases from 3.28 to 9.40 at 1 kHz with doping. Piezoelectric coefficient d33 is also enhanced from 0.24 to 3 pC/N.

  8. Density of photon states in dye-doped chiral nematic liquid crystal cells in the presence of losses and gain.

    PubMed

    Mavrogordatos, Th K; Morris, S M; Castles, F; Hands, P J W; Ford, A D; Coles, H J; Wilkinson, T D

    2012-07-01

    We calculate the density of photon states (DOS) of the normal modes in dye-doped chiral nematic liquid crystal (LC) cells in the presence of various loss mechanisms. Losses and gain are incorporated into the transmission characteristics through the introduction of a small imaginary part in the dielectric constant perpendicular and along the director, for which we assume no frequency dispersion. Theoretical results are presented on the DOS in the region of the photonic band gap for a range of values of the loss coefficient and different values of the optical anisotropy. The obtained values of the DOS at the photonic band gap edges predict a reversal of the dominant modes in the structure. Our results are found to be in good agreement with the experimentally obtained excitation thresholds in chiral nematic LC lasers. The behavior of the DOS is also discussed for amplifying LC cells providing additional insight to the lasing mechanism of these structures. PMID:23005435

  9. Conducting glasses recovered from thin film transistor liquid crystal display wastes for dye-sensitized solar cell cathodes.

    PubMed

    Chen, C-C; Chang, F-C; Peng, C Y; Wang, H Paul

    2015-01-01

    Transparent conductive glasses such as thin film transistor (TFT) array and colour filter glasses were recovered from the TFT-liquid crystal display panel wastes by dismantling and sonic cleaning. Noble metals (i.e. platinum (Pt)) and indium tin oxide (ITO) are generally used in the cathode of a dye-sensitized solar cell (DSSC). To reduce the DSSC cost, Pt was replaced with nano nickel-encapsulated carbon-shell (Ni@C) nanoparticles, which were prepared by carbonization of Ni²⁺-β-cyclodextrin at 673 K for 2 h. The recovered conductive glasses were used in the DSSC electrodes in the substitution of relatively expensive ITO. Interestingly, the efficiency of the DSSC having the Ni@C-coated cathode is as high as 2.54%. Moreover, the cost of the DSSC using the recovered materials can be reduced by at least 24%. PMID:25399759

  10. Flight qualification test results for violet cells

    NASA Technical Reports Server (NTRS)

    Gaddy, E. M.

    1974-01-01

    The violet solar cell has been submitted to a flight qualification program. The tasks included in this program were: to define the violet cell's electrical output from -100 C to +100 C; to determine the violet cell's degradation under 2 MeV, 1 MeV and .3 MeV proton irradiation, under a high humidity environment and under ultraviolet light; to thermal cycle two similar modules of violet cells; to flight qualify a full size violet cell panel for the IMP-J flight; and to obtain a primary balloon-flown standard of the violet cell type. The results of these tests demonstrate that the violet cell is fully qualified for space flight use with no further development work. The tests show that the violet cell offers a power increase of at least twenty-one per cent over presently available commercial cells.

  11. Production and delivery of violet solar cells

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The expansion of conventional violet cells from laboratory numbers to pilot line numbers is described. The basic properties of a violet cell are discussed. The close interaction of all the process steps is emphasized.

  12. Fluorescence screening of leucomalachite green and leucogentian violet residues in catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tripheylmethane dyes malachite green (MG) and gentian violet (GV) are effective fungicides, ectoparasiticides and disinfectants in aquaculture. This practice may leave toxic residues in seafood which is not allowed by FDA and many regulatory agencies worldwide. In this work, residues of their me...

  13. Transfer of Preformed Three-Dimensional Photonic Crystals onto Dye-Sensitized Solar Cells

    SciTech Connect

    Mihi, Agustín; Zhang, Chunjie; Braun, Paul V.

    2011-05-09

    Preformed self-assembled 3D photonic crystals can be infilled with a polycarbonate matrix for mechanical stability and transferred onto rough and porous optoelectronic and photovoltaic devices. This technique allows the incorporation of photonic crystals onto independently processed devices, in which the transferred films have high optical quality.

  14. Spectral properties of bacteriochlorophyll c in nematic liquid crystal. Part 1. Monomeric forms of dye

    NASA Astrophysics Data System (ADS)

    Dudkowiak, A.; Francke, C.; Amesz, J.; Planner, A.; Hanyz, I.; Fraçkowiak, D.

    1996-02-01

    The spectroscopic features of bacteriochlorophyll c and bacteriopheophytin c in a nematic liquid crystal matrix have been investigated. Absorption, circular dichroism, fluorescence and time resolved delayed luminescence spectra have been measured. The pigment is introduced to the liquid crystal from a dry and from a hydrated chloroform solution. In both cases the pigment is in the monomeric form. Hydration of the solvent and the presence or absence of the central Mg atom affect the interaction of the pigment molecules with the liquid crystal matrix, changing the fluorescence anisotropy. A model for the bacteriochlorophyll c orientation in the liquid crystal is proposed and the averaged angles between the transition moments and the liquid crystal orientation axis are determined. A slow process (in the microsecond range) of radiative deactivation of energy absorbed by the pigments is observed. This delayed emission could be due to pigment ionization and delayed charge recombination and/or thermal activation from the triplet to the excited singlet state.

  15. Adsorption and kinetic studies of seven different organic dyes onto magnetite nanoparticles loaded tea waste and removal of them from wastewater samples.

    PubMed

    Madrakian, Tayyebeh; Afkhami, Abbas; Ahmadi, Mazaher

    2012-12-01

    Adsorption of seven different organic dyes from aqueous solutions onto magnetite nanoparticles loaded tea waste (MNLTW) was studied. MNLTW was prepared via a simple method and was fully characterized. The properties of this magnetic adsorbent were characterized by scanning electron microscopy and X-ray diffraction. Adsorption characteristics of the MNLTW adsorbent was examined using Janus green, methylene blue, thionine, crystal violet, Congo red, neutral red and reactive blue 19 as adsorbates. Dyes adsorption process was thoroughly studied from both kinetic and equilibrium points of view for all adsorbents. The experimental isotherm data were analyzed using Langmuir, Freundlich, Sips, Redlich-Peterson, Brouers-Sotolongo and Temkin isotherms. The results from Langmuir isotherm indicated that the capacity of MNLTW for the adsorption of cationic dyes was higher than that for anionic dyes. The adsorption kinetics was tested for the pseudo-first order and pseudo-second order kinetic models at different experimental conditions. PMID:23058993

  16. Adsorption and kinetic studies of seven different organic dyes onto magnetite nanoparticles loaded tea waste and removal of them from wastewater samples

    NASA Astrophysics Data System (ADS)

    Madrakian, Tayyebeh; Afkhami, Abbas; Ahmadi, Mazaher

    2012-12-01

    Adsorption of seven different organic dyes from aqueous solutions onto magnetite nanoparticles loaded tea waste (MNLTW) was studied. MNLTW was prepared via a simple method and was fully characterized. The properties of this magnetic adsorbent were characterized by scanning electron microscopy and X-ray diffraction. Adsorption characteristics of the MNLTW adsorbent was examined using Janus green, methylene blue, thionine, crystal violet, Congo red, neutral red and reactive blue 19 as adsorbates. Dyes adsorption process was thoroughly studied from both kinetic and equilibrium points of view for all adsorbents. The experimental isotherm data were analyzed using Langmuir, Freundlich, Sips, Redlich-Peterson, Brouers-Sotolongo and Temkin isotherms. The results from Langmuir isotherm indicated that the capacity of MNLTW for the adsorption of cationic dyes was higher than that for anionic dyes. The adsorption kinetics was tested for the pseudo-first order and pseudo-second order kinetic models at different experimental conditions.

  17. 27 CFR 21.111 - Gentian violet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Gentian violet. 21.111 Section 21.111 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.111 Gentian violet. (a) Gentian violet...

  18. 21 CFR 589.1000 - Gentian violet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gentian violet. 589.1000 Section 589.1000 Food and... Substances Prohibited From Use in Animal Food or Feed § 589.1000 Gentian violet. The Food and Drug Administration has determined that gentian violet has not been shown by adequate scientific data to be safe...

  19. 21 CFR 589.1000 - Gentian violet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gentian violet. 589.1000 Section 589.1000 Food and... Substances Prohibited From Use in Animal Food or Feed § 589.1000 Gentian violet. The Food and Drug Administration has determined that gentian violet has not been shown by adequate scientific data to be safe...

  20. 21 CFR 589.1000 - Gentian violet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentian violet. 589.1000 Section 589.1000 Food and... Substances Prohibited From Use in Animal Food or Feed § 589.1000 Gentian violet. The Food and Drug Administration has determined that gentian violet has not been shown by adequate scientific data to be safe...

  1. 21 CFR 589.1000 - Gentian violet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gentian violet. 589.1000 Section 589.1000 Food and... Substances Prohibited From Use in Animal Food or Feed § 589.1000 Gentian violet. The Food and Drug Administration has determined that gentian violet has not been shown by adequate scientific data to be safe...

  2. 21 CFR 589.1000 - Gentian violet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gentian violet. 589.1000 Section 589.1000 Food and... Substances Prohibited From Use in Animal Food or Feed § 589.1000 Gentian violet. The Food and Drug Administration has determined that gentian violet has not been shown by adequate scientific data to be safe...

  3. Dyes in Liquid Crystals: Experimental and Computational Studies of a Guest-Host System Based on a Combined DFT and MD Approach.

    PubMed

    Sims, Mark T; Abbott, Laurence C; Cowling, Stephen J; Goodby, John W; Moore, John N

    2015-07-01

    Practical applications of guest-host liquid crystal systems are critically dependent on the alignment of the guest species within the liquid crystal host. UV/Vis absorption spectroscopy shows that the 1,5-dihydroxy-2,6-bis-(4-propylphenyl)-9,10-anthraquinone dye aligns within the E7 nematic host, giving an experimental dichroic ratio of 9.40 and dye order parameter of 0.74. This alignment was modelled by using a combination of density functional theory (DFT) and molecular dynamics (MD) computational approaches that do not require the input of experimental data. Time-dependent DFT calculations show that the electronic transition dipole moment is highly aligned with the long molecular axis of the dye. Fully atomistic MD simulations show that the long axis of the dye is less highly aligned within the E7 host, indicating that this contribution limits the overall dye alignment and, thereby, the potential practical applications of this particular system. Importantly, this study demonstrates an experimental and combined DFT and MD computational approach that may be applied generally to guest-host systems, providing a potential route to their rational design. PMID:26031244

  4. All-optical switching of diffraction gratings infiltrated with dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Lucchetta, D. E.; Vita, F.; Simoni, F.

    2010-12-01

    We report the realization and the characterization of an all-optical switching device based on a transmission grating recorded in a polymeric substrate infiltrated with a methyl red-doped liquid crystal. The properties of this highly nonlinear mixture are exploited to modulate the diffraction of the grating by a pump beam when a static electric field is applied. The behavior of the device is in agreement with the existing model for methyl red-doped liquid crystals.

  5. Photo-tuning of lasing from a dye-doped cholesteric liquid crystals by photoisomerization of a sugar derivative having plural azobenzene groups

    NASA Astrophysics Data System (ADS)

    Kurihara, Seiji; Hatae, Yohko; Yoshioka, Teppei; Moritsugu, Masaki; Ogata, Tomonari; Nonaka, Takamasa

    2006-03-01

    Cholesteric liquid crystal (Ch LC) was prepared by mixing a nematic LC, a sugar derivative having plural azobenzene substituents, and a laser dye. Laser emission from the dye-doped Ch LC was observed at the longer edge of the selective reflection band of the Ch LC. Reversible change in the helical pitch of the Ch LC was caused by the trans-cis photoisomerization of the sugar derivative having plural azobenzene substituents. According to the change in the helical pitch of the Ch LC, the lasing properties were simultaneously affected by the UV and visible light irradiation; laser emission wavelength, intensity, singlemode-multimode.

  6. Optical bistability in a silicon nitride microring resonator with azo dye-doped liquid crystal as cladding material.

    PubMed

    Wang, Chun-Ta; Tseng, Chih-Wei; Yu, Jui-Hao; Li, Yuan-Cheng; Lee, Chun-Hong; Jau, Hung-Chang; Lee, Ming-Chang; Chen, Yung-Jui; Lin, Tsung-Hsien

    2013-05-01

    This investigation reports observations of optical bistability in a silicon nitride (SiN) micro-ring resonator with azo dye-doped liquid crystal cladding. The refractive index of the cladding can be changed by switching the liquid crystal between nematic (NLC) and photo-induced isotropic (PHI) states by. Both the NLC and the PHI states can be maintained for many hours, and can be rapidly switched from one state to the other by photo-induced isomerization using 532 nm and 408 nm addressing light, respectively. The proposed device exhibits optical bistable switching of the resonance wavelength without sustained use of a power source. It has a 1.9 nm maximum spectral shift with a Q-factor of over 10000. The hybrid SiN- LC micro-ring resonator possesses easy switching, long memory, and low power consumption. It therefore has the potential to be used in signal processing elements and switching elements in optically integrated circuits. PMID:23669955

  7. Degradation of textile dyes mediated by plant peroxidases.

    PubMed

    Shaffiqu, T S; Roy, J Jegan; Nair, R Aswathi; Abraham, T Emilia

    2002-01-01

    The peroxidase enzyme from the plants Ipomea palmata (1.003 IU/g of leaf) and Saccharum spontaneum (3.6 IU/g of leaf) can be used as an alternative to the commercial source of horseradish and soybean peroxidase enzyme for the decolorization of textile dyes, mainly azo dyes. Eight textiles dyes currently used by the industry and seven other dyes were selected for decolorization studies at 25-200 mg/L levels using these plant enzymes. The enzymes were purified prior to use by ammonium sulfate precipitation, and ion exchange and gel permeation chromatographic techniques. Peroxidase of S. spontaneum leaf (specific activity of 0.23 IU/mg) could completely degrade Supranol Green and Procion Green HE-4BD (100%) dyes within 1 h, whereas Direct Blue, Procion Brilliant Blue H-7G and Chrysoidine were degraded >70% in 1 h. Peroxidase of Ipomea (I. palmata leaf; specific activity of 0.827 U/mg) degraded 50 mg/L of the dyes Methyl Orange (26%), Crystal Violet (36%), and Supranol Green (68%) in 2-4 h and Brilliant Green (54%), Direct Blue (15%), and Chrysoidine (44%) at the 25 mg/L level in 1 to 2 h of treatment. The Saccharum peroxidase was immobilized on a hydrophobic matrix. Four textile dyes, Procion Navy Blue HER, Procion Brilliant Blue H-7G, Procion Green HE-4BD, and Supranol Green, at an initial concentration of 50 mg/L were completely degraded within 8 h by the enzyme immobilized on the modified polyethylene matrix. The immobilized enzyme was used in a batch reactor for the degradation of Procion Green HE-4BD and the reusability was studied for 15 cycles, and the half-life was found to be 60 h. PMID:12396133

  8. Highly sensitive wavelength-dependent nonaqueous capillary electrophoresis for simultaneous screening of various synthetic organic dyes.

    PubMed

    Park, Moonhee; Bahng, Seung-Hoon; Woo, Nain; Kang, Seong Ho

    2016-05-15

    A novel multi-wavelength nonaqueous capillary electrophoresis (MW-NACE) technique based on wavelength-dependent laser-induced fluorescence (LIF) detection was investigated for the simultaneous screening of various synthetic organic dyes. Multi-wavelength excitation light sources were utilized to excite different organic dyes [e.g., 543 nm for crystal violet (CV), methyl violet B (MVB), methyl violet B base (MBB), rhodamine 6G (R6G), and rhodamine B base (RBB); 635 nm for nile blue A (NBA) and methylene blue (MB)] simultaneously. Using a nonaqueous buffer system composed of 15 mM sodium borate and 835 mM acetic acid in 100% ethanol (pH=5.4), all dyes were analyzed within 15 min with excellent resolution (R≥4.0) under an electric field of 500 V/cm. Calibration curves showed excellent linearity with square of correlation coefficients (r(2)) greater than 0.9908 over wide dynamic ranges of 0.4-50 μM for CV, 0.8-50 μM for MVB, 1.5-50 μM for MBB, 0.08-5 nM for R6G, 0.06-10 μM for MB, 0.02-10 μM for NBA, and 0.13-10 pM for RBB. The detection limits (S/N=3) of 40 fM to 0.5 μM were 10-200,000 times lower than those of previous detection methods. While adjacent peaks were not well distinguished with baseline separation in a single capillary, the devised technique was faster and more sensitive than conventional aqueous and nonaqueous CE approaches, thereby enabling the quantitative analysis of various dyes based on wavelength-dependent fluorescence detection with different excitation wavelengths. PMID:26992516

  9. Light-controlled electric Freedericksz threshold in dye doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Lucchetti, L.; Catani, L.; Simoni, F.

    2014-05-01

    We report the results of measurements of the threshold of Freedericksz transition in a nematic liquid crystal doped by Methyl-red. We show that in case of dc field the threshold voltage can decrease or increase depending on the light dose, due to the light-induced desorption and adsorption of charge complexes from and on the irradiated surface, that has been recently demonstrated. This effect has the potential to be exploited in optical devices such as liquid crystal microlenses and spatial light modulators.

  10. Spectral properties of BChl c in nematic liquid crystals. II: Aggregated form of dye

    NASA Astrophysics Data System (ADS)

    Dudkowiak, A.; Francke, C.; Amesz, J.; Planner, A.; Frackowiak, D.

    1996-11-01

    The orientation properties of aggregated bacteriochlorophyll c in a nematic liquid crystal matrix have been studied by means of polarized steady-state and time-resolved spectroscopy. The pigment introduced to the model system was predominantly in tetrameric (or hexameric) form with absorption maxima located at about 670 and 710 nm. Two tetramers with long-wavelength maxima at 704 and 722 nm could be distinguished. They exhibited different orientations in liquid crystal and different yields of fluorescence. Both tetramers exhibited delayed luminescence in the μs time region.

  11. Light-controlled electric Freedericksz threshold in dye doped liquid crystals

    SciTech Connect

    Lucchetti, L.; Catani, L.; Simoni, F.

    2014-05-28

    We report the results of measurements of the threshold of Freedericksz transition in a nematic liquid crystal doped by Methyl-red. We show that in case of dc field the threshold voltage can decrease or increase depending on the light dose, due to the light-induced desorption and adsorption of charge complexes from and on the irradiated surface, that has been recently demonstrated. This effect has the potential to be exploited in optical devices such as liquid crystal microlenses and spatial light modulators.

  12. Effect of single walled carbon nanotubes on the threshold voltage of dye based photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Manik, N. B.

    2016-01-01

    Carbon nanotubes are being widely used in organic photovoltaic (OPV) devices as their usage has been reported to enhance the device efficiency along with other related parameters. In this work we have studied the energy (Ec) effect of single walled carbon nanotubes (SWCNT) on the threshold voltage (Vth) and also on the trap states of dye based photovoltaic devices. SWCNT is added in a series of dyes such as Rose Bengal (RB), Methyl Red (MR), Malachite Green (MG) and Crystal Violet (CV). By analysing the steady state dark current-voltage (I-V) characteristics Vth and Ec is estimated for the different devices with and without addition of SWCNT. It is observed that on an average for all the dyes Vth is reduced by about 30% in presence of SWCNT. The trap energy Ec also reduces in case of all the dyes. The relation between Vth, Ec and total trap density is discussed. From the photovoltaic measurements it is seen that the different photovoltaic parameters change with addition of SWCNT to the dye based devices. Both the short circuit current density and fill factor are found to increase for all the dye based devices in presence of SWCNT.

  13. Chlorophyll J-aggregates: from bioinspired dye stacks to nanotubes, liquid crystals, and biosupramolecular electronics.

    PubMed

    Sengupta, Sanchita; Würthner, Frank

    2013-11-19

    Among the natural light-harvesting (LH) systems, those of green sulfur and nonsulfur photosynthetic bacteria are exceptional because they lack the support of a protein matrix. Instead, these so-called chlorosomes are based solely on "pigments". These are self-assembled bacteriochlorophyll c, d, and e derivatives, which consist of a chlorophyll skeleton bearing a 3(1)-hydroxy functional group. Chemists consider the latter as an essential structural unit to direct the formation of light-harvesting self-assembled dye aggregates with J-type excitonic coupling. The intriguing properties of chlorosomal J-type aggregates, particularly narrow red-shifted absorption bands, compared with monomers and their ability to delocalize and migrate excitons, have inspired intense research activities toward synthetic analogues in this field. The ultimate goal of this research field is the development of (opto-)electronic devices based on the architectural principle of chlorosomal LH systems. In this regard, the challenge is to develop small, functional building blocks with appropriate substituents that are preprogrammed to self-assemble across different length scales and to emulate functions of natural LH systems or to realize entirely new functions beyond those found in nature. In this Account, we highlight our achievements in the past decade with semisynthetic zinc chlorins (ZnChls) as model compounds of bacteriochlorophylls obtained from the naturally most abundant chlorin precursor: chlorophyll a. To begin, we explore how supramolecular strategies involving π-stacking, hydrogen bonding, and metal-oxygen coordination can be used to design ZnChl-based molecular stack, tube, and liquid crystalline assemblies conducive to charge and energy transport. Our design principle is based on the bioinspired functionalization of the 3(1)-position of ZnChl with a hydroxy or methoxy group; the former gives rise to tubular assemblies, whereas the latter induces stack assemblies. Functionalization

  14. Use of dye tracing to determine ground-water movement to Mammoth Crystal Springs, Sylvan Pass area, Yellowstone National Park, Wyoming

    USGS Publications Warehouse

    Spangler, Lawrence E.; Susong, David D.

    2006-01-01

    At the request of and in cooperation with the Geology Program at Yellowstone National Park, the U.S. Geological Survey conducted a hydrologic investigation of the Sylvan Pass area in June 2005 to determine the relation between surface water and ground-water flow to Mammoth Crystal Springs. Results of a dye-tracing investigation indicate that streamflow lost into talus deposits on Sylvan Pass enters the ground-water system and moves to the southeast to discharge at Mammoth Crystal Springs. Ground-water travel times to the springs from a distance of 1.45 miles and a vertical relief of 500 feet were less than 1 day, indicating apparent rates of movement of at least 8,000 feet per day, values that are similar to those in karst aquifers. Peak dye concentrations were reached about 2 days after dye injection, and transit time of most of the dye mass through the system was about 3 weeks. High permeability and rapid travel times within this aquifer also are indicated by the large variation in springflow in response to snowmelt runoff and precipitation, and by the high concentration of suspended sediment (turbidity) in the water discharging into the spring-fed lake.

  15. Band-tunable color cone lasing emission based on a dye-doped cholesteric liquid crystal film

    NASA Astrophysics Data System (ADS)

    Lee, Chia-Rong; Lin, S.-H.; Yeh, H.-C.; Ji, T.-D.; Liu, J.-H.; Yang, P.-C.; Mo, T.-S.; Huang, S.-Y.; Kuo, C.-T.; Lo, K.-Y.; Fuh, Andy Y.

    2010-02-01

    This investigation reports for the first time a novel phenomenon, called band-tunable color cone lasing emission (CCLE), based on a single-pitched one-dimensional photonic crystal-like dye-doped cholesteric liquid crystal (DDCLC) cell. The lasing wavelength in the CCLE pattern is distributed continuously at 676.7-595.6 nm as the oblique angle increases continuously from 0° to 50° relative to the helical axis. The variation of the lasing wavelength in the CCLE with the oblique angle is consistent with that of the wavelength at the long-wavelength edge (LWE) of the CLC reflection band (CLCRB) with the oblique angle. Simulation results obtained utilizing Berreman's 4×4 matrix method show that, at each oblique angle, the associated group velocity and density of photonic state (DOS) are near zero and large at the shortwavelength edge (SWE) and LWE of the CLCRB, respectively, and are in good agreement with experimental results. The particularly strong lasing ring emission at a cone angle of ~35° can be explained to be likely due to a special effect that, under the condition of overlap between the LWE of the CLCRB measured at 35° and the SWE of the CLCRB measured at 0°, the LWE and SWE fluorescence propagating along 35° and 0°, respectively, may indirectly enhance each other due to individual enhanced rate of spontaneous emission. Furthermore, the lasing band of the CCLE can be tuned from long-wavelength (deep red~orange) to short-wavelength (orange~green) regions by changing the concentration of the chiral or by the photo-irradiation on a DDCLC cell with a photoisoemerizable chiral dopant.

  16. Laser-pointer-induced self-focusing effect in hybrid-aligned dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Aihara, Yosuke; Kinoshita, Motoi; Mamiya, Jun-Ichi; Priimagi, Arri; Shishido, Atsushi

    2015-05-01

    Nonlinear optics deals with phenomena where “light controls light” e.g., there is mediation by an intensity-dependent medium through which light propagates. This field has attracted much attention for its immense potential in applications dependent on nonlinear processes, such as frequency conversion, multiple-photon absorption, self-phase modulation, and so on. However, such nonlinearities are typically only observed at very high light intensities and thus they require costly lasers. Here, we report on a self-focusing effect induced with a 1 mW handheld laser pointer. We prepared polymer-stabilized dye-doped liquid crystals, in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. This is referred to as hybrid alignment. In such films, the threshold intensity needed to form diffraction rings was reduced by a factor of 8.5 compared to that in conventional homeotropic cells, which enabled the induction of the self-focusing effect with a laser pointer.

  17. Laser-pointer-induced self-focusing effect in hybrid-aligned dye-doped liquid crystals.

    PubMed

    Wang, Jing; Aihara, Yosuke; Kinoshita, Motoi; Mamiya, Jun-Ichi; Priimagi, Arri; Shishido, Atsushi

    2015-01-01

    Nonlinear optics deals with phenomena where "light controls light"; e.g., there is mediation by an intensity-dependent medium through which light propagates. This field has attracted much attention for its immense potential in applications dependent on nonlinear processes, such as frequency conversion, multiple-photon absorption, self-phase modulation, and so on. However, such nonlinearities are typically only observed at very high light intensities and thus they require costly lasers. Here, we report on a self-focusing effect induced with a 1 mW handheld laser pointer. We prepared polymer-stabilized dye-doped liquid crystals, in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. This is referred to as hybrid alignment. In such films, the threshold intensity needed to form diffraction rings was reduced by a factor of 8.5 compared to that in conventional homeotropic cells, which enabled the induction of the self-focusing effect with a laser pointer. PMID:25944052

  18. Laser-pointer-induced self-focusing effect in hybrid-aligned dye-doped liquid crystals

    PubMed Central

    Wang, Jing; Aihara, Yosuke; Kinoshita, Motoi; Mamiya, Jun-ichi; Priimagi, Arri; Shishido, Atsushi

    2015-01-01

    Nonlinear optics deals with phenomena where “light controls light”; e.g., there is mediation by an intensity-dependent medium through which light propagates. This field has attracted much attention for its immense potential in applications dependent on nonlinear processes, such as frequency conversion, multiple-photon absorption, self-phase modulation, and so on. However, such nonlinearities are typically only observed at very high light intensities and thus they require costly lasers. Here, we report on a self-focusing effect induced with a 1 mW handheld laser pointer. We prepared polymer-stabilized dye-doped liquid crystals, in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. This is referred to as hybrid alignment. In such films, the threshold intensity needed to form diffraction rings was reduced by a factor of 8.5 compared to that in conventional homeotropic cells, which enabled the induction of the self-focusing effect with a laser pointer. PMID:25944052

  19. Performance evolution of color cone lasing emissions in dye-doped cholesteric liquid crystals at different fabrication conditions.

    PubMed

    Lee, Chia-Rong; Lin, Jia-De; Mo, Ting-Shan; Horng, Chi-Ting; Sun, Han-Ying; Huang, Shuan-Yu

    2015-04-20

    This work investigates the performance evolution of color cone lasing emissions (CCLEs) based on dye-doped cholesteric liquid crystal (DDCLC) cells at different fabrication conditions. Experimental results show that the energy threshold (E(th)) and relative slope efficiency (η(s)) of the lasing signal emitted at each cone angle (0°-35°) in the CCLE decreases and increases, respectively, when the waiting time in a homogenously rubbed aligned DDCLC cell is increased from 0 hr to 216 hr (9 days). This result occurs because defect lines gradually shrink with the anchoring of the surface alignment when the waiting time is increased. Hence, the scattering loss decreases, and the dwelling time of the fluorescence photons in the resonator increases, which in turn enhances the CCLE performance. With the aligned cell given the pretreatment of a rapid annealing processing (RAP), the waiting time for obtaining an optimum CCLE can markedly be reduced sixfold. The surface alignment of the DDCLC cell also plays a necessary role in generating the CCLE. This work provides an insight into the temporal evolution of the performance for the CCLE laser and offers a method (RAP) of significantly speeding up the formation of a CCLE laser with optimum performance. PMID:25969059

  20. Low threshold photonic crystal laser based on a Rhodamine dye doped high gain polymer.

    PubMed

    Shi, Lan-Ting; Jin, Feng; Zheng, Mei-Ling; Dong, Xian-Zi; Chen, Wei-Qiang; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2016-02-21

    We demonstrate low threshold lasing oscillation in a photonic crystal (PhC) laser by using tert-butyl Rhodamine B (t-Bu-RhB) doped gain media. Lactonic t-Bu-RhB is synthesized to improve doping concentration in polymethylmethacrylate (PMMA) films, and then isomerized to the zwitterion form to achieve highly fluorescent gain medium. The t-Bu-RhB doped PMMA film is sandwiched by a pair of polystyrene colloidal crystals to construct a PhC resonating cavity. Single-mode laser oscillation at 592 nm is observed when the PhC resonating cavity is pumped by a Nd:YAG laser. The lasing threshold is 0.12 MW cm(-2) utilizing 6.9 wt% t-Bu-RhB doped PMMA films, which is only 1/60 of that with 3 wt% t-Bu-RhB doped PMMA films. The concentration-dependent lasing action is attributed to different gain factors of the t-Bu-RhB doped PMMA films. Furthermore, a spatially and spectrally coherent laser beam from the PhC resonating cavity is verified by exploring the far-field image and angular dependence of the lasing emission. The approach provides a facile and efficient strategy to reduce the lasing threshold for fabricating low threshold PhC lasers. PMID:26817423

  1. Microgap ultra-violet detector

    DOEpatents

    Wuest, Craig R.; Bionta, Richard M.

    1994-01-01

    A microgap ultra-violet detector of photons with wavelengths less than 400 run (4000 Angstroms) which comprises an anode and a cathode separated by a gas-filled gap and having an electric field placed across the gap. Either the anode or the cathode is semi-transparent to UV light. Upon a UV photon striking the cathode an electron is expelled and accelerated across the gap by the electric field causing interactions with other electrons to create an electron avalanche which contacts the anode. The electron avalanche is detected and converted to an output pulse.

  2. Microgap ultra-violet detector

    DOEpatents

    Wuest, C.R.; Bionta, R.M.

    1994-09-20

    A microgap ultra-violet detector of photons with wavelengths less than 400 run (4,000 Angstroms) which comprises an anode and a cathode separated by a gas-filled gap and having an electric field placed across the gap is disclosed. Either the anode or the cathode is semi-transparent to UV light. Upon a UV photon striking the cathode an electron is expelled and accelerated across the gap by the electric field causing interactions with other electrons to create an electron avalanche which contacts the anode. The electron avalanche is detected and converted to an output pulse. 2 figs.

  3. Ferrofluid based dispersive-solid phase extraction for spectrophotometric determination of dyes.

    PubMed

    Davudabadi Farahani, Malihe; Shemirani, Farzaneh

    2013-10-01

    For the first time, ferrofluid based dispersive-solid phase extraction (D-SPE) has been applied for determination of trace levels of dyes in aqueous and fish samples. The contaminant used as a model compound was crystal violet (CV), a cationic dye, and was preconcentrated without any derivatization or ion-pair formation. The method is based on rapid injection of ferrofluid into the aqueous sample by a syringe. The sample preparation time is decreased by the fact that the sorbent dispersed in the bulk solution and extraction can be achieved very fast. In this way, the separation of sorbent from the aqueous bulk was achieved by a magnet, and no centrifugation is required. These significant features which obtained with this method are of key interest for routine trace laboratory analysis. The influence of different variables on D-SPE was investigated. Under optimum conditions, the calibration graph was linear over the range of 3.3-90 μg L(-1), and the enrichment factor (EF) 267 was obtained. Detection limit was 1.51 μg L(-1) (n=7), and the relative standard deviation of 5.6% at 50 ng mL(-1) was obtained (n=7). The proposed method was successfully applied for the determination of crystal violet in various samples. PMID:23849184

  4. Results from the IMP-J violet solar cell experiment and violet cell balloon flights

    NASA Technical Reports Server (NTRS)

    Gaddy, E. M.

    1976-01-01

    The Interplanetary Monitoring Platform-J violet solar cell experiment was flown in an orbit with mild thermal cycling and low hard-particle radiation. The results of the experiment show that violet cells degrade at about the same rate as conventional cells in such an orbit. Balloon flight measurements show that violet solar cells produce approximately 20% more power than conventional cells.

  5. Results from the IMP-J violet solar cell experiment and violet cell balloon flights

    NASA Technical Reports Server (NTRS)

    Gaddy, E. M.

    1976-01-01

    The IMP-J violet solar cell experiment was flown in an orbit with mild thermal cycling and low hard particle radiation. The results of the experiment show that violet cells degrade at about the same rate as conventional cells in such an orbit. Balloon flight measurements show that violet solar cells produce approximately 20% more power than conventional cells.

  6. Random lasing in a dye doped cholesteric liquid crystal polymer solution

    NASA Astrophysics Data System (ADS)

    He, Benqiao; Liao, Qing; Huang, Yong

    2008-10-01

    Random lasing in rhodamine 6G (R6G) doped ethyl-cryanoethyl cellulose [(E-CE)C]/acrylic acid (AA) cholesteric liquid crystal (LC) solution without scattering particles was studied. The effects of concentration of (E-CE)C/AA solution and the thickness of the sample on the random lasing were investigated. The random laser with coherent feedback occurs in (E-CE)C/AA anisotropic solution, while only amplified spontaneous emission (ASE) is observed in (E-CE)C/AA isotropic solution and AA solvent. The random laser also occurs in the (E-CE)C/poly(acrylic acid) (PAA)/R6G solid film with cholesteric structure through quick polymerization of AA. The experimental results suggest that the cholesteric LC domains play a very important role in this random lasing.

  7. 21 CFR 73.3107 - Carbazole violet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Carbazole violet. 73.3107 Section 73.3107 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3107 Carbazole violet. (a) Identity. The...

  8. 21 CFR 73.3107 - Carbazole violet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Carbazole violet. 73.3107 Section 73.3107 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3107 Carbazole violet. (a) Identity. The...

  9. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  10. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  11. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  12. Pulsed electric linear dichroism of triphenylmethane dyes adsorbed on montmorillonite K10 in aqueous media

    SciTech Connect

    Yamaoka, Kiwamu; Sasai, Ryo

    2000-05-01

    Electric linear dichroism (ELD) spectra of two cationic triphenylmethane dyes, crystal violet (CV) and malachite green (MG), bound to sodium montmorillonite K10 (MK-10) were studied at 20 C in aqueous media at two mixing ratios, D/S, of 0.10 and 0.24 in the 700- to 400 nm wavelength region and in the applied electric field strength range between 0 and 3 kV/cm. The specific parallel and perpendicular dichroism ({Delta}A{sub {parallel}}/A and {Delta}A{sub {perpendicular}}/A) spectra of dye-adsorbed MK-10 suspension were measured at a fixed field strength with an apparatus equipped with a 512-channel photodiode array detector. By changing the field strength over a wide range, a series of the reduced dichroism values of the bound dyes were measured at a fixed wavelength. By fitting these dichroism values to theoretical orientation functions, the intrinsic reduced dichroism ({Delta}A/A){sub int} spectra at the limiting high fields (ELD spectrum) were determined for CV and MG bound to MK-10. No appreciable difference was observed at the two D/S values. The ELD spectra of these bound dyes are undulatory but never constant, throughout their absorption region; thus, the dye plane does not lie flatly either on the surface or between layers of MK-10 particle.

  13. Nonlinear experimental dye-doped nematic liquid crystal optical transmission spectra estimated by neural network empirical physical formulas

    NASA Astrophysics Data System (ADS)

    Yildiz, Nihat; San, Sait Eren; Köysal, Oğuz

    2010-09-01

    In this paper, two complementary objectives related to optical transmission spectra of nematic liquid crystals (NLCs) were achieved. First, at room temperature, for both pure and dye (DR9) doped E7 NLCs, the 10-250 W halogen lamp transmission spectra (wavelength 400-1200 nm) were measured at various bias voltages. Second, because the measured spectra were inherently highly nonlinear, it was difficult to construct explicit empirical physical formulas (EPFs) to employ as transmittance functions. To avoid this difficulty, layered feedforward neural networks (LFNNs) were used to construct explicit EPFs for these theoretically unknown nonlinear NLC transmittance functions. As we theoretically showed in a previous work, a LFNN, as an excellent nonlinear function approximator, is highly relevant to EPF construction. The LFNN-EPFs efficiently and consistently estimated both the measured and yet-to-be-measured nonlinear transmittance response values. The experimentally obtained doping ratio dependencies and applied bias voltage responses of transmittance were also confirmed by LFFN-EPFs. This clearly indicates that physical laws embedded in the physical data can be faithfully extracted by the suitable LFNNs. The extraordinary success achieved with LFNN here suggests two potential applications. First, although not attempted here, these LFNN-EPFs, by such mathematical operations as derivation, integration, minimization etc., can be used to obtain further transmittance related functions of NLCs. Second, for a given NLC response function, whose theoretical nonlinear functional form is yet unknown, a suitable experimental data based LFNN-EPF can be constructed to predict the yet-to-be-measured values.

  14. The potential for human exposure, direct and indirect, to the suspected carcinogenic triphenylmethane dye Brilliant Green from green paper towels.

    PubMed

    Oplatowska, Michalina; Donnelly, Ryan F; Majithiya, Rita J; Glenn Kennedy, D; Elliott, Christopher T

    2011-08-01

    Triphenylmethanes - Malachite Green (MG), Crystal Violet (CV) and Brilliant Green (BG) are dyes with known genotoxic and carcinogenic properties. Apart from being illegally used in aquaculture for treatment of fish diseases they are also applied in industry such as paper production to colour paper towels widely used in hospitals, factories and other locations for hand drying after washing. The present study provides evidence that the triphenylmethane dye (BG) present in green paper towels can migrate through the skin even when the exposure time is short (30-300 s). The transfer of the dye from the towel to food (fish) was also studied and a high amount of colour was found to migrate during overnight exposure. The risk to humans associated with these two dye transfer studies was assessed using a 'margin of exposure approach' on the basis of the toxicological data available for the closely related dye MG and its metabolite Leucomalachite Green. The data indicated that the risk associated with the use of triphenylmethane containing paper towels is of a similar proportion to the risk associated with consumption of fish contaminated with these dyes due to the illegal application in aquaculture. PMID:21596089

  15. Photo Inactivation of Streptococcus mutans Biofilm by Violet-Blue light.

    PubMed

    Gomez, Grace F; Huang, Ruijie; MacPherson, Meoghan; Ferreira Zandona, Andrea G; Gregory, Richard L

    2016-09-01

    Among various preventive approaches, non-invasive phototherapy/photodynamic therapy is one of the methods used to control oral biofilm. Studies indicate that light at specific wavelengths has a potent antibacterial effect. The objective of this study was to determine the effectiveness of violet-blue light at 380-440 nm to inhibit biofilm formation of Streptococcus mutans or kill S. mutans. S. mutans UA159 biofilm cells were grown for 12-16 h in 96-well flat-bottom microtiter plates using tryptic soy broth (TSB) or TSB with 1 % sucrose (TSBS). Biofilm was irradiated with violet-blue light for 5 min. After exposure, plates were re-incubated at 37 °C for either 2 or 6 h to allow the bacteria to recover. A crystal violet biofilm assay was used to determine relative densities of the biofilm cells grown in TSB, but not in TSBS, exposed to violet-blue light. The results indicated a statistically significant (P < 0.05) decrease compared to the non-treated groups after the 2 or 6 h recovery period. Growth rates of planktonic and biofilm cells indicated a significant reduction in the growth rate of the violet-blue light-treated groups grown in TSB and TSBS. Biofilm viability assays confirmed a statistically significant difference between violet-blue light-treated and non-treated groups in TSB and TSBS. Visible violet-blue light of the electromagnetic spectrum has the ability to inhibit S. mutans growth and reduce the formation of S. mutans biofilm. This in vitro study demonstrated that violet-blue light has the capacity to inhibit S. mutans biofilm formation. Potential clinical applications of light therapy in the future remain bright in preventing the development and progression of dental caries. PMID:27278805

  16. Magnetic solid-phase extraction for determination of the total malachite green, gentian violet and leucomalachite green, leucogentian violet in aquaculture water by high-performance liquid chromatography with fluorescence detection.

    PubMed

    Zhao, Jiao; Wei, Daqiao; Yang, Yaling

    2016-06-01

    In this study, magnetic multi-walled carbon nanotube nanoparticles were synthesized and used as the adsorbent for the sums of malachite green, gentian violet and leucomalachite green, leucogentian violet in aquaculture water samples followed by high performance liquid chromatography with fluorescence detection. This method was based on in situ reduction of chromic malachite green, gentian violet to colorless leucomalachite green, leucogentian violet with potassium borohydride, respectively. The obtained adsorbent combines the advantages of carbon nanotubes and Fe3 O4 nanoparticles in one material for separation and preconcentration of the reductive dyes in aqueous media. The structure and properties of the prepared nanoparticles were characterized by transmission and scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The main parameters affecting the adsorption recoveries were investigated and optimized, including reducing agent concentration, type and amount of sorbent, sample pH, and eluting conditions. Under the optimum conditions, the limits of detection in this method were 0.22 and 0.09 ng/mL for malachite green and gentian violet, respectively. Product recoveries ranged from 87.0 to 92.8% with relative standard deviations from 4.6 to 5.9%. The results indicate that the sorbent is a suitable material for the removal and concentration of triphenylmethane dyes from polluted environmental samples. PMID:27120413

  17. Photoinduced reordering in thin azo-dye films and light-induced reorientation dynamics of the nematic liquid-crystal easy axis.

    PubMed

    Kiselev, Alexei D; Chigrinov, V G; Pasechnik, S V; Dubtsov, A V

    2012-07-01

    We theoretically study the kinetics of photoinduced reordering triggered by linearly polarized (LP) reorienting light in thin azo-dye films that were initially illuminated with LP ultraviolet pumping beam. The process of reordering is treated as a rotational diffusion of molecules in the light intensity-dependent mean-field potential. The two-dimensional diffusion model which is based on the free energy rotational Fokker-Planck equation and describes the regime of in-plane reorientation is generalized to analyze the dynamics of the azo-dye order parameter tensor at varying polarization azimuth of the reorienting light. It is found that, in the photosteady state, the intensity of LP reorienting light determines the scalar order parameter (the largest eigenvalue of the order parameter tensor), whereas the steady state orientation of the corresponding eigenvector (the in-plane principal axis) depends solely on the polarization azimuth. We show that, under certain conditions, reorientation takes place only if the reorienting light intensity exceeds its critical value. Such threshold behavior is predicted to occur in the bistability region provided that the initial principal axis lies in the polarization plane of reorienting light. The model is used to interpret the experimental data on the light-induced azimuthal gliding of the liquid-crystal easy axis on photoaligned azo-dye substrates. PMID:23005436

  18. Temperature and orientation dependence of surface relief gratings based on dye-doped polymer film with the interface of nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Huang, Shuan-Yu; Huang, Bing-Yau; Hung, Wen-Chi; Yu, Kai-Yu; Cheng, Wen-Shou; Kuo, Chie-Tong

    2011-02-01

    The formation of surface relief grating on dye-doped polymer film with the interface of nematic liquid crystals has been investigated by means of the holographic technique. The first-order diffraction efficiency of surface relief grating depends on the temperature and the orientation of molecular director in the interface of nematic liquid crystals. The diffraction efficiency is roughly independent of thermal fluctuations of molecular director in the most part of nematic temperature range and apparently drops near the transition temperature. The morphology of surface relief grating demonstrates that the surface modulation is larger for molecular director parallel to the groove direction. The experimental result also shows that the first-order diffraction efficiency is dependent on the surface modulation of surface relief grating.

  19. Uptake of dyes by a promising locally available agricultural solid waste: coir pith.

    PubMed

    Namasivayam, C; Radhika, R; Suba, S

    2001-01-01

    The adsorption of rhodamine-B and acid violet by coir pith carbon was carried out by varying the parameters such as agitation time, dye concentration, adsorbent dose and pH. The adsorption followed both Langmuir and Freundlich isotherms. The adsorption capacity was found to be 2.56 mg and 8.06 mg dye per g of the adsorbent for rhodamine-B and acid violet, respectively. Adsorption of dyes followed first order rate kinetics. Acidic pH was favorable for the adsorption of acid violet and alkaline pH was favorable to rhodamine-B. Desorption studies showed that alkaline pH was favorable for the desorption of acid violet and acidic pH was favorable for the desorption of rhodamine-B. PMID:11300538

  20. Geopolymeric adsorbents from fly ash for dye removal from aqueous solution

    SciTech Connect

    Li, L.; Wang, S.B.; Zhu, Z.H.

    2006-08-01

    Adsorbents from coal fly ash treated by a solid-state fusion method using NaOH were prepared. It was found that amorphous aluminosilicate, geopolymers would be formed. These fly ash-derived inorganic polymers were assessed as potential adsorbents for removal of some basic dyes, methylene blue and crystal violet, from aqueous solution. It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 1.2:1 weight ratio of Na:fly-ash at 250-350{sup o}C. The synthesised materials exhibit much higher adsorption capacity than fly ash itself and natural zeolite. The adsorption isotherm can be fitted by Langmuir and Freundlich models while the two-site Langmuir model produced the best results. It was also found that the fly ash derived geopolymeric adsorbents show higher adsorption capacity for crystal violet than methylene blue and the adsorption temperature influences the adsorption capacity. Kinetic studies show that the adsorption process follows the pseudo second-order kinetics.

  1. Surface microstructural features of scales in relation to toxic stress of Basic Violet-1.

    PubMed

    Kaur, Kirandeep; Kaur, Ramandeep; Kaur, Arvinder

    2016-01-01

    The present work deals with scanning electron microscopic (SEM) studies of the scales of Labeo rohita on exposure to lethal and sublethal doses of Basic Violet-1 (an important textile and hair colorant). The dye induced loosening of the scales and caused breakage and disorganization of lepidonts. Erosion of lepidonts occurred mostly in the fish exposed to 0.20 and 0.40 mg/L dye, during acute exposure and to 0.0225 and 0.045 mg/L dye, during the subchronic exposure. However, lepidonts were sloughed off from their sockets in 0.60 and 0.80 mg/L dye during acute exposure and in 0.09 mg/L dye during the subchronic exposure. Circuli, the base that provides anchorage to the lepidonts, got damaged, and tubercles responsible for coloration of a fish became atrophied with an increase in the duration of exposure. The results of the present investigation clearly indicated that exposure to Basic Violet-1 (BV-1) even at a concentration as low as 0.0225 mg was responsible for deleterious changes in the scale morphology of the test fish after 150 days of exposure. Similar changes were observed in the scales of the dead fish also. It can thus be suggested that this noninvasive technique is very helpful for evaluating the health status of an aquatic body. At the same time, the changes in ultramorphology of scales can act as an early indicator of the stress of very minute doses of dyes and even the scales of a dead fish can act as indicators of the untoward changes that would have occurred in the environment of the fish before death. PMID:26432273

  2. A novel carboxyethyltin functionalized sandwich-type germanotungstate: synthesis, crystal structure, photosensitivity, and application in dye-sensitized solar cells.

    PubMed

    Sang, Xiaojing; Li, Jiansheng; Zhang, Lancui; Wang, Zanjiao; Chen, Weilin; Zhu, Zaiming; Su, Zhongmin; Wang, Enbo

    2014-05-28

    A novel sandwich-type germanotungstate [C(NH2)3]10[Mn2{Sn(CH2)2COOH}2(B-α-GeW9O34)2]·8H2O (1) represents the first single crystalline polyoxometalate (POM) functionalized by open chain carboxyethyltin, which was designed and synthesized in aqueous solution and applied to a dye-sensitized solar cell (DSSC) for the first time. Its photosensitivity was explored through a fluorescence spectrum (FL), surface photovoltage spectrum (SPV), electrochemical method, and solid diffuse spectrum. 1 displays the primary features of sensitizers in DSSCs, and the efficiency of the solar cell is 0.22%. Delightedly, when 1 was employed to assemble a cosensitized solar cell configuration by preparing a 1-doped TiO2 electrode and additionally adsorbing N719 dyes, a considerably improved efficiency was achieved through increasing spectral absorption and accelerating electron transport, which is 19.4% higher than that of single N719 sensitization. This result opens up a new way to position different dyes on a single TiO2 film for cosensitization. PMID:24758570

  3. Dye-Sensitized Approaches to Photovoltaics

    NASA Astrophysics Data System (ADS)

    Grätzel, Michael

    2008-03-01

    reaction of such a hole is the photocorrosion of the semiconductor itself. However, only relatively narrow band-gap materials have an effective optical absorption through the visible spectrum, towards and into the infra-red. Materials with an optimal band-gap match to the solar spectrum, of the order of 1.5eV, are therefore electrochemically unstable. A stable photoelectrochemical cell, without some process of optical sensitization, and necessarily using a wide-gap semiconductor is sensitive only to the ultra-violet limit of the visible spectrum. Over recent years a suitable combination of semiconductor and sensitizer has been identified and optimized, so that now a solar spectrum conversion efficiency of over 11% has been verified in a sensitized photoelectrochemical device. One key to such an efficient system is the suppression of recombination losses. When the excited dye relaxes by electron loss, the separated charge carriers find themselves on opposite sides of a phase barrier -- the electron within the solid-state semiconductor, the positive charge externally, in association with the dye molecule. There is no valence---band involvement in the process, so the system represents a majority-carrier device, avoiding one of the major loss mechanisms in conventional photovoltaics. In consequence also a highly-disordered, even porous, semiconductor structure is acceptable, enabling surface adsorption of a sufficient concentration of the dye to permit total optical absorption of incident light of photon energy greater than the HOMO-LUMO gap of the dye molecule. The accepted wide-band semiconductor for photoelectrochemical applications is titanium dioxide in the anatase crystal structure. The size of the nanocrystals making up the semiconductor photoanode can be determined by hydrothermal processing of a precursor sol, and the film can be deposited on a transparent conducting oxide (TCO) substrate by any convenient thin-film process such as screen printing or tape casting. The

  4. Stability and efficiency of dye-sensitized solar cells based on papaya-leaf dye

    NASA Astrophysics Data System (ADS)

    Suyitno, Suyitno; Saputra, Trisma Jaya; Supriyanto, Agus; Arifin, Zainal

    2015-09-01

    The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450 °C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8 g/100 mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it.

  5. Stability and efficiency of dye-sensitized solar cells based on papaya-leaf dye.

    PubMed

    Suyitno, Suyitno; Saputra, Trisma Jaya; Supriyanto, Agus; Arifin, Zainal

    2015-09-01

    The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450 °C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8 g/100 mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it. PMID:25875031

  6. Precipitation diagram and optimization of crystallization conditions at low ionic strength for deglycosylated dye-decolorizing peroxidase from a basidiomycete

    SciTech Connect

    Saijo, Shinya; Sato, Takao; Tanaka, Nobuo; Ichiyanagi, Atsushi; Sugano, Yasushi; Shoda, Makoto

    2005-08-01

    Precipitation phase diagrams can be rapidly constructed using dispensing-robot technology. These diagrams provide information that assists in optimization of crystal growth. The growth of suitably sized protein crystals is essential for protein structure determination by X-ray crystallography. In general, crystals are grown using a trial-and-error method. However, these methods have been modified with the advent of microlitre dispensing-robot technology and of protocols that rapidly screen for crystal nucleation conditions. The use of one such automatic dispenser for mixing protein drops (1.3–2.0 µl in volume) of known concentration and pH with precipitating solutions (ejecting 2.0 µl droplets) containing salt is described here. The results of the experiments are relevant to a crystallization approach based on a two-step procedure: screening for the crystal nucleation step employing robotics followed by optimization of the crystallization conditions using incomplete factorial experimental design. Large crystals have successfully been obtained using quantities as small as 3.52 mg protein.

  7. Resonant Rayleigh scattering for the determination of trace amounts of mercury (II) with thiocyanate and basic triphenylmethane dyes

    SciTech Connect

    Liu, S.; Liu, Z.; Zhou, G.

    1998-05-01

    Intense resonance Rayleigh scattering (RRS) appears when mercury (II) reacts with thiocyanate and a basic triphenylmethane dye (BTPMD), such as crystal violet (CV), ethyl violet (EV), brilliant green (BG), malachite green (MG) or indine green (IG), to form an ion-association complex of the type (BTPMD){sub 2}[Hg(SCN){sub 4}]. The characteristics of RRS spectra of the ion-association complexes and suitable conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of mercury (II) in the range of 0--2.0 {micro}g/25 ml. The RRS methods have very high sensitivities for determination of mercury (II); their detection limits are between 1.68 ng/ml and 6.00 ng/ml on different dye systems. The effects of foreign ions and ways to improve the selectivity were studied. The new highly sensitive methods for the determination of trace amounts of mercury based on the RRS of the ion-association complexes have been developed.

  8. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling.

    PubMed

    Izadmanesh, Y; Ghasemi, Jahan B

    2016-08-01

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26±0.01), 1:1 (1.53±0.08), 1:1 (3.11±0.04), 1:1 (1.06±0.12), and 2:1 (5.27±0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper. PMID:27111153

  9. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling

    NASA Astrophysics Data System (ADS)

    Izadmanesh, Y.; Ghasemi, Jahan B.

    2016-08-01

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100 μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26 ± 0.01), 1:1 (1.53 ± 0.08), 1:1 (3.11 ± 0.04), 1:1 (1.06 ± 0.12), and 2:1 (5.27 ± 0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper.

  10. Role of laccase and low molecular weight metabolites from Trametes versicolor in dye decolorization.

    PubMed

    Moldes, Diego; Fernández-Fernández, María; Sanromán, M Ángeles

    2012-01-01

    The studies regarding decolorization of dyes by laccase may not only inform about the possible application of this enzyme for environmental purposes, but also may provide important information about its reaction mechanism and the influence of several factors that could be involved. In this paper, decolorization of crystal violet and phenol red was carried out with different fractions of extracellular liquids from Trametes versicolor cultures, in order to describe the role of laccase in this reaction. Moreover, the possible role of the low molecular weight metabolites (LMWMs) also produced by the fungus was evaluated. The results confirm the existence of a nonenzymatic decolorization factor, since the nonprotein fraction of the extracellular liquids from cultures of T. versicolor has shown decolorization capability. Several experiments were performed in order to identify the main compounds related to this ability, which are probably low molecular weight peroxide compounds. PMID:22566767