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1

Characterization of a PDLC mixed with crystal violet dye  

NASA Astrophysics Data System (ADS)

We show the optical characterization of a Polymer Dispersed Liquid Crystal which was made mixing Norland Optical Adhesive No. 65®, nematic liquid crystal and crystal violet dye, deposited between two glass substrates with indium tin oxide (ITO) as electrodes. In this device, we recorded low frequency (104 lines/mm) holographic gratings made with the interference of two beams from an Ar laser at 515 nm in emission line. We measured the diffraction efficiency of the gratings obtaining 2% when the grating was read with a beam from a He-Ne laser at 612 nm.

Villa-Manríquez, José Fabián; Ortiz-Gutiérrez, Mauricio; Pérez-Cortés, Mario; Ibarra-Torres, Juan Carlos; Olivares-Pérez, Arturo; Ordoñez-Padilla, Manuel Jorge

2012-02-01

2

Studies on the utility of plant cellulose waste for the bioadsorption of crystal violet dye.  

PubMed

Several synthetic dyes employed in textile and food industries are discharged into aquatic environment. These visible pollutants in water damage environment, as they are carcinogenic and toxic to humans. The use of cost effective and ecofriendly plant cellulose based adsorbents have been studied in batch experiments as an alternative and effective substitution of activated carbon for the removal of toxic dyes from waste water. Adsorbents prepared from sugarcane baggase, were successfully used to remove certain textile dye such as crystal violet from an aqueous solution. The present investigation potentiate the use of sugarcane baggase, pretreated with formaldehyde (referred as Raw Baggase) and sulphuric acid (referred as Chemically Activated Baggase), for the removal of crystal violet dye from simulated waste water. Experiments were carried out at neutral pH with various parameters like dye concentration, temperature, contact time and adsorbent dosage. Efficiency of raw baggase was found better than chemically activated baggase for adsorption of crystal violet dye. The data obtained perfectly fits in the Freundlich adsorption isotherm. PMID:21046996

Mahesh, S; Kumar, G Vijay; Agrawal, Pushpa

2010-05-01

3

Efficient removal of crystal violet dye from aqueous solutions by vitreous tuff mineral.  

PubMed

Textural, structural and morphological characteristics of the vitreous tuff were determined by means of several physicochemical techniques. The nitrogen adsorption isotherm at 77 K was fitted with the Brunnauer-Emmet-Teller model and together with the results of the average pore distribution showed a mesoporous material. Samples of vitreous tuff were used as adsorbent to study the removal of crystal violet from aqueous solution. The presence of -OH moieties in the material seems to be responsible for the removal of the dye showing that vitreous tuff can be used as an organic dye adsorbent material. The pseudo-second-order model was the best fit model for describing the sorption process of crystal violet; intraparticle diffusion being the controlling step in the process. The experimental adsorption isotherm was fitted with Langmuir, Freundlich and Langmuir-Freundlich models, showing better correlation with the second one. The adsorption capacity was 170.01 mg/g, being among the highest compared with other inorganic and organic common sorbent materials. The design of single stage of the adsorber can predict the behaviour to potential scale up. This mineral has a very good potential as an adsorbent material for organic dyes. PMID:24701950

Blanco-Flores, A; Colín-Cruz, A; Gutiérrez-Segura, E; Sánchez-Mendieta, V; Solís-Casados, D A; Garrudo-Guirado, M A; Batista-González, R

2014-01-01

4

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

NASA Technical Reports Server (NTRS)

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 methodology minimizes many external variable effects and enables small changes in absorption to be measured. This research also compares the advantages of this innovative LED light source design over traditional mercury black light systems and non- LED lamp approaches. This novel technology begins to address the growing need for a standard method that can assess the performance of photocatalytic materials before deployment for large scale, real world use.

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

2009-01-01

5

Photocatalytic studies of crystal violet dye using mn doped and PVP capped ZnO nanoparticles.  

PubMed

Mn (0.5%, 1%, 1.5% and 2%) doped and undoped ZnO nanoparticles (NPs) capped with PVP (1.0%) were successfully synthesized via co-precipitation approach using zinc acetate, sodium hydroxide and manganese acetate as precursors. Structural analysis was performed by XRD confirming phase purity and crystalline wurtzite structure. TEM results show average particle size 15-20 nm and 22-25 nm for Mn (1%) and Mn (2%) doped ZnO NPs respectively. Manganese (Mn) doping has led to reduction in band gap which facilitate the absorption of radiation in visible region. The Photocatalytic activity of undoped and Mn (0.5%,1%,1.5% and 2%) doped NPs was analyzed via degradation of crystal violet (CV) dye. The crystal violet decomposition rate of undoped and Mn doped NPs were studied under UV-visible region. It is observed from degradation studies that the doping has a pronounced effect on the photocatalytic activity of ZnO NPs. Kinetic studies shows that photo degradation of CV follow a pseudo first-order kinetic law. Experiments for reusability of Mn (1%) doped with PVP (1%) capped ZnO were also performed to determine the stability of as prepared sample. It shows an increase in catalytic activity of NPs by small amount when exposed to UV irradiation for 3 h. Photoluminescence and UV-Visible absorption spectroscopy studies were also performed for studying the effect of UV irradiation on the surface of ZnO NPs. PMID:24734685

Mittal, Manish; Sharma, Manoj; Pandey, O P

2014-04-01

6

Optimizing adsorption of crystal violet dye from water by magnetic nanocomposite using response surface modeling approach.  

PubMed

A magnetic nanocomposite was developed and characterized. Adsorption of crystal violet (CV) dye from water was studied using the nanocomposite. A four-factor central composite design (CCD) combined with response surface modeling (RSM) was employed for maximizing CV removal from aqueous solution by the nanocomposite based on 30 different experimental data obtained in a batch study. Four independent variables, viz. temperature (10-50°C), pH of solution (2-10), dye concentration (240-400 mg/l), and adsorbent dose (1-5 g/l) were transformed to coded values and a second-order quadratic model was built to predict the responses. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Adequacy of the model was tested by the correlation between experimental and predicted values of the response and enumeration of prediction errors. Optimization of the process variables for maximum adsorption of CV by nanocomposite was performed using the quadratic model. The Langmuir adsorption capacity of the adsorbent was determined as 81.70 mg/g. The model predicted maximum adsorption of 113.31 mg/g under the optimum conditions of variables (concentration 240 mg/l; temperature 50°C; pH 8.50; dose 1g/l), which was very close to the experimental value (111.80 mg/g) determined in batch experiment. PMID:21211903

Singh, Kunwar P; Gupta, Shikha; Singh, Arun K; Sinha, Sarita

2011-02-28

7

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

NASA Astrophysics Data System (ADS)

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.

Babic, Steven; Battista, Jerry; Jordan, Kevin

2009-11-01

8

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

PubMed

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 mm(2) 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 mm(2) 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 ( approximately 4% per degree 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. PMID:19847015

Babic, Steven; Battista, Jerry; Jordan, Kevin

2009-11-21

9

Removal of Basic Dye Crystal Violet from Aqueous Solution by Cu(II)Loaded Montmorillonite  

Microsoft Academic Search

The effects of contact time, reaction temperature, and ionic strength on crystal violet adsorption onto Cu(II)-loaded montmorillonite were studied. The kinetic experimental data were analyzed using pseudo-first-order, pseudo-second-order, and Elovich equations to examine the adsorption mechanism. The result suggested that the adsorption was best represented by the pseudo-second-order equation. The suitability of the Langmuir, Freundich, and Temkin isotherms to equilibrium

Xue Song Wang; Wei Zhang

2011-01-01

10

Degradation of Crystal violet by Nocardia corallina  

Microsoft Academic Search

Crystal Violet (BV3), a typical triphenylmethane dye, was degraded by growing cells of Nocardia corallina IAM 12121, although their growth was inhibited at the initial stage of incubation. The dye was degraded at a low concentration, below 5 µmol dm-3. The growth of the cells was completely inhibited at a dye concentration of 7 µmol dm-3. A degradation product of

Chizuko Yatome; Shigeyuki Yamada; Toshihiko Ogawa; Masaki Matsui

1993-01-01

11

Equilibrium, kinetics and mechanism modeling and simulation of basic and acid dyes sorption onto jute fiber carbon: Eosin yellow, malachite green and crystal violet single component systems  

Microsoft Academic Search

Batch experiments were carried out for the sorption of eosin yellow, malachite green and crystal violet onto jute fiber carbon (JFC). The operating variables studied are the initial dye concentration, initial solution pH, adsorbent dosage and contact time. Experimental equilibrium data were fitted to Freundlich, Langmuir and Redlich–Peterson isotherm by non-linear regression method. Langmuir isotherm was found to be the

K. Porkodi; K. Vasanth Kumar

2007-01-01

12

Determination of residues of three triphenylmethane dyes and their metabolites (malachite green, leuco malachite green, crystal violet, leuco crystal violet, and brilliant green) in aquaculture products by LC/MS/MS: first action 2012.25.  

PubMed

During the AOAC Annual Meeting held from September 30 to October 3, 2012 in Las Vegas, NV, the Expert Review Panel (ERP) on Veterinary Drug Residues reviewed data for the method for determination of residues of three triphenylmethane dyes and their metabolites (malachite green, leuco malachite green, crystal violet, leuco crystal violet, and brilliant green) in aquaculture products by LC/MS/MS, previously published in the Journal of Chromatography A 1218, 1632-1645 (2006). The method data were reviewed and compared to the standard method performance requirements (SMPRs) found in SMPR 2009.001, published in AOAC's Official Methods of Analysis, 19th Ed. (2012). The ERP determined that the data were acceptable, and the method was approved AOAC Official First Action. The method uses acetonitrile to isolate the analyte from the matrix. Then determination is conducted by LCIMS/MS with positive electrospray ionization. Accuracy ranged from 100.1 to 109.8% for samples fortified at levels of 0.5, 0.75, 1.0, and 2.0 microg/kg. Precision ranged from 2.0 to 10.3% RSD for the intraday samples and 1.9 to 10.6% for the interday samples analyzed over 3 days. The described method is designed to accurately operate in the analytical range from 0.5 to 2 microg/kg, where the minimum required performance limit for laboratories has been fixed in the European Union at 2.0 microg/kg for these banned substances and their metabolites. Upper levels of concentrations (1-100 microg/kg) can be analyzed depending on the different optional calibrations used. PMID:24282960

Hurtaud-Pessel, Dominique; Couëdor, Pierrick; Verdon, Eric; Dowell, Dawn

2013-01-01

13

Crystal Violet, Fluorenone, and Fluorene  

NSDL National Science Digital Library

The WebWare molecules of the month for the month of September are discussed in the article by Gail Horowitz, "A Discovery Approach to Three Organic Laboratory Techniques: Extraction, Recrystallization, and Distillation". In the extraction part of the experiment, students use aqueous washes to remove a highly polar colored contaminent (crystal violet) or a nonpolar colored contaminent (fluorenone) from a desired compound (fluorene).

14

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

PubMed

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

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

2013-03-01

15

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)

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.

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

2010-06-01

16

Analysis of incurred crystal violet in Atlantic salmon (Salmo salar L.): comparison between the analysis of crystal violet as an individual parent and leucocrystal violet and as total crystal violet after oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone.  

PubMed

Due to on-going concern about the occurrence of triphenylmethane dye residues in fish destined for human consumption, a depletion study of crystal violet in salmon was carried out. Atlantic salmon less than 12 months old were exposed to crystal violet in fresh water at 15°C and subsequently sampled at 1, 7, 14, 28, 63 and 91 days after exposure. The salmon were then analysed by two analytical methods. In the first method, 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) was used to oxidise leucocrystal violet to its parent form. Total parent crystal violet was then analysed by LC-MS/MS. In the second method, crystal violet and leucocrystal violet were analysed individually by LC-MS/MS without oxidation. Both methods gave comparable results for total crystal violet concentrations, with a correlation of r(2)=0.69. Statistical treatment for 88 incurred salmon samples showed no significant difference between the two sets of results with t=1.68 and t(crit)=1.99. Up to 98% of crystal violet was metabolised to its leuco form in the salmon after 1 day of exposure and could be detected at significant concentrations (approximately 20 µg kg(-1)) 91 days after exposure. The depletion data also suggest that crystal violet has a half-life of approximately 15-16 days in salmon. PMID:22043964

Chan, D; Tarbin, J A; Stubbings, G; Kay, J; Sharman, M

2012-01-01

17

Bioremediation of crystal violet using air bubble bioreactor packed with Pseudomonas aeruginosa.  

PubMed

Seven water and sediment samples were collected and tested for decolorizing crystal violet. Pseudomonas aeruginosa was the most effective isolate for dye decolorization. The LC50 of the crystal violet (115 mg/l) was measured using Artemia salina as a biomarker. The effect of different heavy metals on crystal violet decolorization was investigated. Cd2+ and Fe3+ ions showed marginal enhancement of the decolorization process, the rate was 1.35 mg/l/h compared to (1.25 mg/l/h) for the control. Phenol and m-cresol showed no effect on crystal violet decolorization, meanwhile p-cresol and p-nitrophenol reduced the decolorization rate to 1.07 and 0.01 mg/l/h, respectively. P. aeruginosa cells were immobilized by entrapment in agar-alginate beads. The beads were cultivated and reused in Erlenmeyer flask and in an air bubble column bioreactor and they enhanced the crystal violet decolorization rate to 3.33 and 7.5 mg/l/h, respectively. PMID:16316674

Manal, M A; El-Naggar, Samy; El-Aasar, A; Barakat Khlood, I

2005-12-01

18

SERS and DFT study of crystal violet  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

19

Sorption of acid violet 17 and direct red 80 dyes on cotton fiber from aqueous solutions  

Microsoft Academic Search

Sorption of acid violet 17 and direct red 80 azo dyes on locally available cotton fiber from aqueous solution has been investigated as a function of shaking time, pH, dyes concentration and temperature. Maximum sorption of acid violet 17 and direct red 80 on cotton fiber was achieved within 30 and 60min of shaking time and at pH 8 and

M. Saleem; Tahira Pirzada; Riaz Qadeer

2007-01-01

20

TOXICITY OF AN ANTHRAQUINONE VIOLET DYE MIXTURE FOLLOWING INHALATION EXPOSURE, INTRACHEAL INSTILLATION, OR GAVAGE  

EPA Science Inventory

Anthraquinone dyes in a variety of functions from drug formulations fabric colorative to area markings as might be used of the military. he effects of a prototype violet dye mixture (VDM) consisting of: Disperse Red 11 (DR11) 1,4-diamino-2-methoxy-anthraquinone and Disperse Blue ...

21

Reactions in microemulsions. IV. Kinetics of chlorophyll sensitized photoreduction of methyl red and crystal violet by ascorbate  

Microsoft Academic Search

The photoreduction of adsorbed dye (methyl red and crystal violet) sensitized by chlorophyll a in an anionic mineral oil in water microemulsion system has been investigated. The 100-A microdroplets occupy 40% of the total volume, and at the pigment concentrations employed (less than or equal to 10 ..mu..M) there is on the average less than one chlorophyll molecule per drop.

C. E. Jones; C. A. Jones; R. A. Mackay

1979-01-01

22

Violet-to-red photoluminescence of spiro-TAD organic films doped with different organic dyes  

NASA Astrophysics Data System (ADS)

Photoluminescence (PL) and photoluminescence excitation (PLE) spectra of undoped spiro-TAD films and spiro-TAD films doped either by the organic dyes coumarin 7 or DCM as well as by both of these dyes simultaneously were investigated at different dye concentrations. A widened PL spectrum caused by doping was encountered and violet-to-red emission was obtained. It was established that excitation of the dyes is realized most efficiently through spiro-TAD. The overall integral PL intensity of the coumarin 7 doped films increased with dye concentration due to the suppression of nonradiative recombination in the film caused by a transfer of spiro-TAD excitation energy to the dye molecules. Mainly radiative energy transfer from semiconductor to dye molecules occurs in the case of DCM doping. No mutual influence on the luminescence of both dyes in the spiro-TAD film was observed and as a consequence, the PL band intensity of each dye can be adjusted separately.

Osipov, K. A.; Pavlovskii, V. N.; Lutsenko, E. V.; Gurskii, A. L.; Effendiev, T. S.; Katarkevich, V. N.; Yablonskii, G. P.; van Gemmern, P.; Zimmermann, C.; Jessen, F.; Kalisch, H.; Jansen, R. H.; Heuken, M.

2007-05-01

23

Adsorption kinetics and mechanism of cationic methyl violet and methylene blue dyes onto sepiolite  

Microsoft Academic Search

The use of low-cost and ecofriendly adsorbents was investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. Sepiolite was used as an adsorbent for the removal of methyl violet (MV) and methylene blue (MB) from aqueous solutions. The rate of adsorption was investigated under various parameters such as contact time, stirring speed, ionic strength,

Mehmet Do?an; Yasemin Özdemir; Mahir Alkan

2007-01-01

24

Efficient energy transfer dye lasers in spectral region of near ultraviolet to violet  

NASA Astrophysics Data System (ADS)

An experiment was performed on the operation and development of energy-transfer dye lasers (ETDL), using scintillator dye mixture to obtain higher efficiency and an expanded range of wavelengths in the ultraviolet-to-violet region, in which an N2 laser is used for excitation. High lasing efficiencies were observed with alpha NPO dimethyl POPOP, PPF/alpha NPO, and some other dye mixtures; and overlapping lasing was observed, involving the donor and acceptor dye-laser regions. A blue shift of the oscillation frequency was analyzed theoretically, and the theoretical results concerning the dependence of the oscillation wavelength on laser power and donor dye concentration were in good agreement with observations.

Muto, S.; Ito, C.; Inaba, H.

1982-11-01

25

Holographic characteristics of two different films using methyl violet dyes in polyvinyl alcohol matrices  

NASA Astrophysics Data System (ADS)

Holographic characteristics of two different films using methyl violet dyes in polyvinyl alcohol matrices are reported. One of the films, Film A, contains only methyl violet in the matrix. The other film, Film B, contains methyl violet, triethanolamine and acrylamide in the matrix. Diffraction efficiencies of the two films were measured and compared. Mechanisms of holographic recording and the functions of the dyes are discussed. The films were 8 ?m thick. Holographic gratings were recorded in the films by two intersecting YVO laser beams at 532 nm. The recording intensity of each beam was 25 mW, 50 mW and 100 mW, and the beam diameter was 2.25 mm. The spatial frequency of the grating was 653 line/mm. During recording, intensity of the diffracted light was simultaneously measured using a He-Ne laser at 633 nm. Regarding Film A, diffraction efficiency reaches a peak at a specific exposure time. This means that holographic grating grows according to exposure time in low exposure, but vanishes when over-exposed. In bright regions of the interference fringe on the film, the dyes are bleached. Changes of absorption and refractive index due to bleaching would result in the holographic grating. Regarding Film B, the diffraction efficiency was saturated in high exposure, and the maximum diffraction efficiency was not strongly dependent on the concentration of methyl violet. In the bright regions of the interference fringe on the film, excited methyl violet and triethanolamine cause polymerization of acrylamide. Changes in the refractive index due to the polymerization build the holographic grating.

Tsuchida, Keiichi; Ohkawa, Masashi; Sekine, Seishi

2005-04-01

26

Isolation and Applications of Prostate Side Population Cells Based on Dye Cycle Violet Efflux  

PubMed Central

This unit describes methods for the digestion of human prostate clinical specimens, dye cycle violet (DCV) staining procedure for the identification, isolation, and quantitation of radiolabeled dihydrotestosterone (DHT) retention of side population cells. The principle of the side population assay is based on differential efflux of DCV, a cell membrane permeable fluorescent dye, by cells with high ATP binding cassette (ABC) transporter activity. Cells with high ABC transporter activity efflux DCV and fall in the lower left quadrant of a flow cytograph are designated as “side population” cells. This unit emphasizes tissue digestion, DCV staining, flow settings for sorting side population cells and quantitation of radiolabeled DHT retention.

Gangavarapu, Kalyan J.; Huss, Wendy J.

2011-01-01

27

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

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.

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

1991-01-01

28

Comparative electrochemical degradation of the triphenylmethane dye Methyl Violet with boron-doped diamond and Pt anodes  

Microsoft Academic Search

The electrochemical degradation of the triphenylmethane dye Methyl Violet (MV) in acidic and neutral aqueous solutions has been comparatively studied in an undivided electrolytic cell containing either a boron-doped diamond (BDD) or Pt anode and a stainless steel cathode under galvanostatic conditions. The dye solutions are completely decolorized and mineralized using BDD, but both processes become much slower when using

Morched Hamza; Ridha Abdelhedi; Enric Brillas; Ignasi Sirés

2009-01-01

29

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,...

30

Background-free, fast protein staining in sodium dodecyl sulfate polyacrylamide gel using counterion dyes, zincon and ethyl violet.  

PubMed

A background-free, fast protein staining method in polyacrylamide gel electrophoresis using an acidic dye, zincon (ZC) and a basic dye, ethyl violet (EV) is described. It is based on the counterion dye staining technique that employs two oppositely charged dyes to form an ion-pair complex in staining solution. The selective binding of free dye molecules to proteins in acidic solution produces bluish violet-colored bands. It is a rapid and end-point staining procedure, involving only fixing and staining steps that are completed in 1-1.5 h. The detection limit of this method is 8-15 ng of protein that is comparable to the sensitivity of the colloidal Coomassie Brilliant Blue G (CBBG) stain. Due to its sensitivity and speed, this stain may be more practical than any other dye-based stains for routine laboratory purposes. PMID:12481259

Choi, Jung-Kap; Tak, Keong-Hoon; Jin, Li-Tai; Hwang, Sun-Young; Kwon, Tae-Ik; Yoo, Gyurng-Soo

2002-12-01

31

Kinetic, isotherm and thermodynamic studies of the adsorption of crystal violet by activated carbon from peanut shells.  

PubMed

The adsorption of crystal violet dye from aqueous solutions onto an activated carbon prepared from peanut shells was analyzed in this study. The effects of particle size, initial concentration, time and temperature on crystal violet removal were studied in batch experiments. Experimental results showed that the adsorption equilibrium was achieved within 100 min for all studied concentrations. Analysis of adsorption results showed that the adsorption isotherms could be well fitted to the Langmuir model. Kinetic parameters, rate constants, equilibrium adsorption capacities and related correlation coefficients for pseudo first-order and second-order kinetic models were calculated and discussed. The results revealed that the adsorption kinetics was in good agreement with the pseudo second-order equation. Thermodynamic parameters such as the change of Gibbs free energy (?G°), change of enthalpy (?H°) and change of entropy (?S°) have also been determined and it has been found that the adsorption process should be spontaneous, endothermic and physisorption in nature. PMID:23306250

Zhang, J X; Ou, L L

2013-01-01

32

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

PubMed

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

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

2013-10-15

33

Biosorption characteristics of Aspergillus fumigatus for the decolorization of triphenylmethane dye acid violet 49.  

PubMed

This study focuses on the possible use of Aspergillus fumigatus to remove acid violet 49 dye (AV49) from aqueous solution. In batch biosorption experiments, the highest biosorption efficiency was achieved at pH 3.0, with biosorbent dosage of 3.0 gL(-1) within about 30 min at 40 °C. The Langmuir and Freundlich models were able to describe the biosorption equilibrium of AV49 onto fungal biomass with maximum dye uptake capacity 136.98 mg g(-1). Biosorption followed a pseudo-second-order kinetic model with high correlation coefficients (R (2)?>?0.99), and the biosorption rate constants increased with increasing temperature. Thermodynamic parameters indicated that the biosorption process was favorable, spontaneous, and endothermic in nature, with insignificant entropy changes. Fourier transform infrared spectroscopy strongly supported the presence of several functional groups responsible for dye-biosorbent interaction. Fungal biomass was regenerated with 0.1 M sodium hydroxide and could be reused a number of times without significant loss of biosorption activity. The effective decolorization of AV49 in simulated conditions indicated the potential use of biomass for the removal of color contaminants from wastewater. PMID:24136473

Chaudhry, Muhammad Tausif; Zohaib, Muhammad; Rauf, Naseem; Tahir, Subhe Sadiq; Parvez, Shoukat

2014-04-01

34

Catalytic Activity of Biomorphic ?-MoO3 in the Degradation of Methyl Violet Dye  

PubMed Central

Abstract A network of fibers comprising orthorhombic molybdenum trioxide (?-MoO3) crystals were synthesized using paper as template via a biomorphic approach. The template was completely removed by annealing the sample at 600°C for 5?min. Monoclinic MoO3 was formed and consequently converted into orthorhombic ?-MoO3 after prolonged annealing. Three milligrams of the biomorphic ?-MoO3 could degrade up to 90% of a methyl violet aqueous solution with a concentration of 20?mg/L under normal visible light. The size of the ?-MoO3 grains and the porosity of the biomorphic sample affected catalytic performance.

Diao, Zhenyu; Kwong, Fung-Luen; Li, Jia; Lian, Jiabiao; Lai, Kwing-To; Ng, Dickon H.L.

2012-01-01

35

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

NASA Astrophysics Data System (ADS)

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.

Bharathi, Kandaswamy Suyamboo; Ramesh, SriKrishna Perumal Thanga

2013-12-01

36

Activation of H 2O 2 by Amberlyst-15 resin supported with copper(II)-complexes towards oxidation of crystal violet  

Microsoft Academic Search

Copper(II) amine complexes supported on Amberlyst-15 cation resin were prepared and characterized by SEM, EDX and FTIR measurements. The kinetics of the heterogeneous oxidation of an organic dye, crystal violet, with H2O2 catalyzed by the supported catalysts was investigated in aqueous solution. The rate of reaction increases with increasing stability of the copper(II) amine complexes. The oxidation rate attained a

Ibrahim A. Salem

2001-01-01

37

Isolation and Characterization of Paracoccus sp. GSM2 Capable of Degrading Textile Azo Dye Reactive Violet 5  

PubMed Central

A potential bacterial strain GSM2, capable of degrading an azo dye Reactive Violet 5 as a sole source of carbon, was isolated from textile mill effluent from Solapur, India. The 16S rDNA sequence and phenotypic characteristics indicated an isolated organism as Paracoccus sp. GSM2. This strain exhibited complete decolorization of Reactive Violet 5 (100?mg/L) within 16?h, while maximally it could decolorize 800?mg/L of dye within 38 h with 73% decolorization under static condition. For color removal, the most suitable pH and temperature were pH 6.0–9.0 and 25–40°C, respectively. The isolate was able to decolorize more than 70% of five structurally different azo dyes within 38 h. The isolate is salt tolerant as it can bring out more than 90% decolorization up to a salt concentration of 2% (w/v). UV-Visible absorption spectra before and after decolorization suggested that decolorization was due to biodegradation and was further confirmed by FT-IR spectroscopy. Overall results indicate the effectiveness of the strain GSM2 explored for the treatment of textile industry effluents containing various azo dyes. To our knowledge, this could be the first report on biodegradation of Reactive Violet 5 by Paracoccus sp. GSM2.

Bheemaraddi, Mallikarjun C.; Shivannavar, Channappa T.; Gaddad, Subhashchandra M.

2014-01-01

38

Final Report on the Safety Assessment of Basic Violet 1, Basic Violet 3, and Basic Violet 4  

Microsoft Academic Search

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

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

2009-01-01

39

Determination of cationic polyelectrolytes using a photometric titration with crystal violet as a color indicator.  

PubMed

The reaction of the cationic dye, crystal violet (CV) with the anionic polyelectrolytes such as potassium poly (vinyl sulfate) (PVSK) results in a decrease of the absorbance of CV at the maximum absorption wavelength (590 nm). This change of the absorption spectra of the CV has been already applied to the determination of anionic polyelectrolytes using flow injection analysis method. In this paper, CV was applied to the indicator for the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by photometric titration, using a PVSK solution as a titrant. The end-point of the titration is detected as the break point of the titration curve. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 0 to 5 x 10(-5) eq. mol dm(-3) for Cat-floc, glycol chitosan and methylglycol chitosan. The effects of the concentration of CV and coexisting electrolytes in the sample solution and the effect of pH of the sample solution on the degree of the change of absorbance at the end-point were also examined. PMID:18968953

Masadome, Takashi

2003-03-10

40

Harmonic rayleigh scattering from nonlinear octupolar molecular media: the case of crystal violet  

NASA Astrophysics Data System (ADS)

Experimental evidence is provided to supplement earlier molecular engineering propositions as to the high nonlinearities of octupolar origin. The absence of dipole moment in such structures precludes the utilization of electric-field-induced second-harmonic generation (EFISH) in solution: harmonic light scattering (HLS), which does not require dipolar electric field poling, is shown to provide quantitative access to the quadratic nonlinearity of octupolar nonlinear molecules. Crystal violet, a trigonal conjugated cationic dye with electronic charge transfer from peripheral dimethylamino donor groups to an electron deficient sp 2 hybridized central carbon atom, is chosen to illustrate the relevance of HLS in this context as well as provide an experimental estimate of the ? magnitude of a prototypical octupolar system. A resonantly enhanced ? value of 580 × 10 -30 esu is found at 1.064 ?m, in acetone solution (? max = 590 nm). Due care is taken of solvent calibration while a detailed account of symmetry considerations and tensorial averaging in solution are provided for various molecular point groups of relevance (D 3, D 3h, C 2v and T d). It is shown that besides the exploration of the new family of octupolar nonlinear systems, the HLS experiment should be also used to revisit the more traditional dipolar molecular systems: it complements EFISH experiments in providing a measure of the anisotropy of molecular quadratic hyperpolarizabilities.

Zyss, Joseph; Van, Thai Chau; Dhenaut, Christophe; Ledoux, Isabelle

1993-11-01

41

Activation of H2O2 by Amberlyst-15 resin supported with copper(II)-complexes towards oxidation of crystal violet.  

PubMed

Copper(II) amine complexes supported on Amberlyst-15 cation resin were prepared and characterized by SEM, EDX and FTIR measurements. The kinetics of the heterogeneous oxidation of an organic dye, crystal violet, with H2O2 catalyzed by the supported catalysts was investigated in aqueous solution. The rate of reaction increases with increasing stability of the copper(II) amine complexes. The oxidation rate attained a first-order in the catalyst and the dye only at lower concentrations and second order in H2O2. A very fast formation of a peroxo-dye intermediate resulting from the interaction of H2O2 with the dye even in the presence of the catalyst was observed. PMID:11513398

Salem, I A

2001-08-01

42

Solid phase adsorption of crystal violet lactone on silica nanoparticles to probe mechanochemical surface modification.  

PubMed

The solid phase adsorption of crystal violet lactone (CVL) on five types of Stober silica nanopowders with BET specific surface areas in the range of 50-800 m2/g under dry milling conditions was described for the first time. The hydrogen bonding between surface silanol and the carboxylate of the ring-opened triphenylmethane dye (CVL+) led to the formation of monolayers of CVL+ in a flat-laid configuration. The lambda max of CVL+ in diffusive reflection visible spectra was influenced by the particle size of silica powders, suggesting that the microenvironmental polarity of adsorbed CVL+ is considerably reduced along with the decrease of the particle size. The solid phase adsorption of CVL obeyed Langmuir adsorption isotherms to give a saturated amount of CVL+ for every silica nanoparticle. The surface concentration of CVL+ on nanoparticles at the saturation was estimated to be 0.31 mg/m2 on average, disclosing that about 52% of the surface can be covered by CVL+ under the assumption that the BET-specific surface areas are equivalent to the real surfaces active for the CVL adsorption. The generation of the blue color of CVL provided a convenient means to estimate qualitative and quantitative analysis of the surface coverage with surface-active reagents, which conceal surface silanols. Subsequently, silica nanoparticles were milled with a surface modifier, followed by milling with CVL to observe the intensity of the blue color in order to disclose that the surface coverage with oligo- and polyethylene glycols as well as with nonionic surfactants by dry milling was specifically determined by the number of repeating oxyethylene units. Although the surface-active reagents were easily desorbed in water, the desorption was notably suppressed by milling with CVL, suggesting that the surface-modified particles with the surface-active reagents are covered with ultrathin films of CVL. PMID:18537277

Ichimura, Kunihiro; Funabiki, Akira; Aoki, Ken-ichi; Akiyama, Haruhisa

2008-06-01

43

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

PubMed

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

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

2010-09-01

44

Dye sensitization of single crystal semiconductor electrodes.  

PubMed

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 40 years. Even today single crystal surfaces prove to be more controlled experimental models for the study of dye-sensitized semiconductors than the nanocrystalline substrates. This Account analyzes 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 SnS(2) and TiO(2) electrodes to serve as reproducible model systems for charge separation at dye-sensitized solar cells. This process involves cleaving the SnS(2) electrodes and a photoelectrochemical surface treatment for TiO(2) 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. In recent experiments with ruthenium complexes at TiO(2) and with carboxylated cyanine dyes, we demonstrate the promise of this simple model for understanding dye-sensitized solar cells. In each of these systems, we can observe and analyze the complex photochemistry in a quantitative manner. Molecules of the well-known N3 ruthenium complex attach to four different crystallographic faces of anatase and rutile TiO(2) at different rates and to a different extent. With carboxylated cyanine dye sensitizers on these surfaces, molecular aggregation on the surface is a function of molecular structure and crystallographic face. In contrast with the N3 sensitizer these organic dyes undergo a photoinduced dimerization and desorption reaction when hydroquinone regenerators are present. With both classes of sensitizers, we demonstrate a new photochronocoulometric technique that quantifies the amount of attached dye on the electrode surface. We have completed initial experiments examining quantum dot sensitization of TiO(2) crystals, which could eventually lead to sensitizers with higher stability and absorption coefficients. Although these single crystal electrode models show promise for providing insights and predictive value in understanding the sensitization process, more sophisticated models will be needed to fully understand the charge transfer from the localized electronic states of the sensitizer to the extended states of the semiconductor. PMID:19924998

Spitler, Mark T; Parkinson, B A

2009-12-21

45

Burkholderia vietnamiensis C09V as the functional biomaterial used to remove crystal violet and Cu(II).  

PubMed

Burkholderia vietnamiensis C09V (B.V. C09V) was used to remove both crystal violet (CV) and Cu(II) because dye effluents often contain dyes and metal ions. Inhibiting the strain?s growth through the biosorption of Cu(II) on B.V. C09V and promoting its growth by using CV as a carbon source led to the degradation of CV (30mg/L). It fell to 36.9 percent and the amount of Cu(II) (50mg/L) removed rose to 34.9 percent in the presence of both CV and Cu(II). This outcome is comparable to the single presence of CV and Cu(II). EDS analysis showed that Cu(II) was adsorbed onto the strain (the atomic percentage of Cu(II) was 1.9 percent), while kinetic studies indicated that firstly, the decolorization of CV fitted well to the pseudo first-order degradation kinetic model and secondly, the biosorption of Cu(II) fitted well to the pseudo second-order kinetic model. The degradation rate constants of CV were stable in the 0.101-0.0068/h range and R(2) was both higher than 0.981 when Cu(II) concentrations were present. Furthermore, the biosorption capacity of Cu(II) ranged from 38.8 to 20.3mg/g at the CV concentration of 30mg/L (both R(2)>0.96). This suggests that the strain has the potential to degrade CV and facilitate the biosorption of Cu(II) in dye effluent. PMID:24780226

Zhou, Fengfei; Cheng, Ying; Gan, Li; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

2014-07-01

46

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

PubMed Central

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.

2012-01-01

47

Colour Removal from Synthetic Dye Wastewater Using a Bioadsorbent  

Microsoft Academic Search

Removal of dyes (Crystal Violet, Methylene Blue, Malachite Greenand Rhodamine B) from aqueous solutions at differentconcentrations, pH and temperatures by Neem sawdust has beencarried out successfully. The percentage of the dye adsorbed byNeem sawdust decreased from 91.56 to 78.94 and 84.93 to 71.25 for Crystal Violet and Malachite Green, respectively, when the concentration of the dye was increased from 6

S. D. Khattri; M. K. Singh

2000-01-01

48

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

PubMed

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

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

2010-07-15

49

Quantifying hydrogen peroxide in iron-containing solutions using leuco crystal violet  

PubMed Central

Hydrogen peroxide is present in many natural waters and wastewaters. In the presence of Fe(II), this species decomposes to form hydroxyl radicals, that are extremely reactive. Hence, in the presence of Fe(II), hydrogen peroxide is difficult to detect because of its short lifetime. Here, we show an expanded use of a hydrogen peroxide quantification technique using leuco crystal violet (LCV) for solutions of varying pH and iron concentration. In the presence of the biocatalyst peroxidase, LCV is oxidized by hydrogen peroxide, forming a colored crystal violet ion (CV+), which is stable for days. The LCV method uses standard equipment and allows for detection at the low microM concentration level. Results show strong pH dependence with maximum LCV oxidation at pH 4.23. By chelating dissolved Fe(II) with EDTA, hydrogen peroxide can be stabilized for analysis. Results are presented for hydrogen peroxide quantification in pyrite–water slurries. Pyrite–water slurries show surface area dependent generation of hydrogen peroxide only in the presence of EDTA, which chelates dissolved Fe(II). Given the stability of CV+, this method is particularly useful for field work that involves the detection of hydrogen peroxide.

Cohn, Corey A; Pak, Aimee; Strongin, Daniel; Schoonen, Martin A

2005-01-01

50

Modified dynamical equation for dye doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

Dye doped liquid crystals show changed dielectric properties in comparison to pure liquid crystals. These changes are strongly dependent on the concentration of dye. In the present work we have measured dielectric properties of standard nematic liquid crystals E-24 and its two guest host mixtures of different concentrations with Anthraquinone dye D5. The experimental results are fitted using linear response and in the light of this we have proposed some modifications in the dynamical equation for the nematic liquid crystals by introducing two new variables as dye concentration coefficients. The limitations of the proposed equation in high temperature range have also been discussed. With the help of the proposed dynamical equation for the guest-host liquid crystals (GHLCs) it is possible to predict the various parameters like rotational viscosity, dielectric anisotropy and relaxation time for GHLCs at other concentrations of dye in liquid crystals theoretically.

Manohar, Rajiv; Misra, Abhishek Kumar; Srivastava, Abhishek Kumar

2010-04-01

51

Determination of crystal violet in seawater and seafood samples through off-line molecularly imprinted SPE followed by HPLC with diode-array detection.  

PubMed

A highly selective sample cleanup procedure combined with molecularly imprinted SPE was developed for the isolation of crystal violet from seawater and seafood samples. The molecularly imprinted polymer was prepared using crystal violet as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The crystal violet-imprinted polymer was used as the selective sorbent for the SPE of crystal violet. An off-line molecularly imprinted SPE method followed by HPLC with diode-array detection for the analysis of crystal violet was also established. Good linearity on the molecularly imprinted SPE columns was obtained from 0 to 200 ?g/L (R(2) > 0.99). The result demonstrated that the proposed method can be used for the direct determination of crystal violet in seawater and seafood samples. Finally, five samples were analyzed and the following crystal violet concentrations were obtained: 0.92 and 0.52 ?g/L in two seawater samples, as well as 0.36 and 0.27 ?g/kg in two seafood samples. There is no crystal violet detected in the third seawater sample. PMID:23390113

Lian, Ziru; Wang, Jiangtao

2013-03-01

52

Removal of Orange-G and Methyl Violet dyes by adsorption onto bagasse fly ash—kinetic study and equilibrium isotherm analyses  

Microsoft Academic Search

In the study, bagasse fly ash (BFA) (generated as waste material from sugar mill), was used as an adsorbent for the removal of Orange-G (OG), and Methyl Violet (MV), from aqueous solution. Batch studies were performed to address various experimental parameters like pH, contact time, adsorbent dose and initial concentration for the removal of these dyes. Effective pH for OG

Indra D. Mall; Vimal C. Srivastava; Nitin K. Agarwal

2006-01-01

53

Reaction of chrysotile asbestos with triphenylmethane dyes  

Microsoft Academic Search

Triphenylmethane dyes react at ambient conditions with chrysotile asbestos to form homogeneously coloured fibres. Formation of the chelates on the fibre varies: for Basic Fuchsin, Malachite Green and Methyl Blue equilibrium is reached in 1 h, the concentration on the fibre is 1% to 2.4%, and increases slightly on boiling. For Brilliant Blue R, Crystal Violet, and Methyl Violet equilibrium

Farouk T. Awadalla; Fathi Habashi

1990-01-01

54

Blue-violet photoluminescence of 4-isopropyl-pyridine hydroxide crystals.  

PubMed

There is continuing interest in determining essential structural features of polymer gels, which display photoelectric and/or thermoelectric behavior. One such gel is the blend, poly(4-vinylpyridine-co-butyl methacrylate)/poly(4-vinylpyridine), dissolved in liquid pyridine. Following extended aeration of a three-component mixture, which serves as a model for the gel side chain interactions, crystallization of a new molecule, 4-isopropylpyridine hydroxide (IPPOH), occurs. X-ray diffraction, DFT modeling, and spectroscopy were used to determine the structural, electronic, and luminescent properties of the crystal. The crystal structure reveals molecules forming head-to-tail, hydrogen-bonded chains without base stacking or marked interchain interaction. The molecular chains are characterized by moderately long-lived, blue-violet luminescence excited in the near-UV. Because these photoluminescent properties resemble those of the gel from which the crystals are derived, we may posit similar structural features in the gel for which direct structural analysis is not available. PMID:24708153

Vaganova, Evgenia; Wachtel, Ellen; Leitus, Gregory; Danovich, David; Popov, Inna; Dubnikova, Faina; Yitzchaik, Shlomo

2014-05-01

55

Simultaneous evaluation of cell viability by neutral red, MTT and crystal violet staining assays of the same cells  

Microsoft Academic Search

By combining three separate toxic assays, the neutral red (NR), MTT and crystal violet staining assays (CVS), we developed a convenient assay method, the NMC assay, in which the NR, MTT and CVS assays are performed consecutively on the same cultured HeLa cells. The NMC assay is performed as follows: the cultured HeLa cells are first treated with NR, and

K Chiba; K Kawakami; K Tohyama

1998-01-01

56

Optical properties of organic dyes in nanoporous zeolite crystals  

NASA Astrophysics Data System (ADS)

Organic dye molecules of styryl 7 were introduced into the channels of AlPO4-5 single crystals. Polarized absorption and photoluminescence spectra of the dye molecules were investigated. The polarization angle dependence of the absorption and photoluminescence intensity indicates that the dye molecules are highly oriented in the channels. The hexagonal-shaped AlPO4-5 single crystal serves as a natural microcavity for lasing action of the dye molecules. The microcavity modes of the lasing action were also demonstrated.

Li, Irene L.; Tang, Z. K.; Xiao, X. D.; Yang, C. L.; Ge, W. K.

2003-09-01

57

Removal of dyes and their mixtures from aqueous solution using liquid emulsion membrane  

Microsoft Academic Search

Extraction of dyes from aqueous solution was studied using liquid emulsion membrane. Study was carried out using two dyes, namely, crystal violet (CV) and methylene blue (MB). Extraction of single component system of each dye and their binary mixture were investigated. Liquid emulsion membrane was formed using n-heptane as membrane phase, sodium hydroxide solution as the internal phase and dye

Chandan Das; Meha Rungta; Gagandeep Arya; Sunando DasGupta; Sirshendu De

2008-01-01

58

Adsorption of basic dyes from aqueous solution onto pumice powder  

Microsoft Academic Search

The adsorption of methylene blue and crystal violet on pumice powder samples of varying compositions was investigated using a batch adsorption technique. The effects of various experimental parameters, such as adsorbent dosage, initial dye concentration, and contact time, were also investigated. The extent of dye removal increased with decreased initial concentration of the dye and also increased with increased contact

Feryal Akbal

2005-01-01

59

Role of dye structure in photoinduced reorientation of dye-doped liquid crystals  

NASA Astrophysics Data System (ADS)

The giant optical nonlinearity associated with photoinduced molecular reorientation of dye-doped nematic liquid crystals has been measured for a homologous set of dyes belonging to the anthraquinone family, dissolved both in a polar and in a nonpolar liquid crystal host. We found a strong sensitivity of the nonlinearity merit figure to the detailed structure of the dye substituent groups. Our results provide some insight into the molecular mechanisms underlying this phenomenon, whose full understanding will finally require a detailed picture of guest-host intermolecular interactions and their dependence on the molecule electronic state.

Marrucci, L.; Paparo, D.; Vetrano, M. R.; Colicchio, M.; Santamato, E.; Viscardi, G.

2000-12-01

60

[Spectrophotometric determination of microamount phosphorus with crystal violet-heteropoly molybdophosphoric acid in the presence of starch].  

PubMed

The determination of phosphorus with crystal violet-heteropoly molybdophosphoric acid in the presence of starch has been studied. In the medium of 0.15 mol.L-1 H2SO4, the apparent molar absorptivity of the ion associated complex is 1.98 x 10(5) L.cm-1.mol-1 at 548 nm, and it is stable for more than 24 hours. Beer's law is obeyed over the range of 0-8 micrograms.(50 mL)-1 for phosphorus. The molar ratio of heteropoly molybdophosphoric acid to crystal violet is established to be 1:5. The method is satisfactory for the determination of phosphorus in iron basic samples. PMID:12938332

Kai, Xiao-ming

2002-06-01

61

Determination of dextran sulfate sodium with crystal violet by triple-wavelength overlapping resonance Rayleigh scattering  

NASA Astrophysics Data System (ADS)

A triple-wavelength overlapping resonance Rayleigh scattering (TWO-RRS) method was developed to detect dextran sulfate sodium (DSS) with crystal violet (CV). At pH 10.0 Britton Robinson buffer solution medium, the interaction of CV with DSS occurred which greatly enhanced the RRS intensity with the new RRS peaks appearing at 340, 501 and 671 nm and all these three peaks enhanced with the increase of DSS concentration in the range of 0.04-2.5 ?g ml -1 and the detection limit for the three single peaks was 0.024, 0.027, and 0.027 ?g ml -1, respectively, whereas that of the TWO-RRS method was 0.013 ?g ml -1. The TWO-RRS method was found to have much better flexibility and high sensitivity than the single-wavelength method. In this paper, the interaction conditions were optimized. The affecting factors and characteristics of RRS for the interaction of DSS with CV were investigated and a sensitive method for the determination of trace amounts of DSS using the TWO-RRS method was developed.

Hao, Xiu Li; Li, Nian Bing; Luo, Hong Qun

2009-01-01

62

Determination of dextran sulfate sodium with crystal violet by triple-wavelength overlapping resonance Rayleigh scattering.  

PubMed

A triple-wavelength overlapping resonance Rayleigh scattering (TWO-RRS) method was developed to detect dextran sulfate sodium (DSS) with crystal violet (CV). At pH 10.0 Britton Robinson buffer solution medium, the interaction of CV with DSS occurred which greatly enhanced the RRS intensity with the new RRS peaks appearing at 340, 501 and 671 nm and all these three peaks enhanced with the increase of DSS concentration in the range of 0.04-2.5 microg ml(-1) and the detection limit for the three single peaks was 0.024, 0.027, and 0.027 microg ml(-1), respectively, whereas that of the TWO-RRS method was 0.013 microg ml(-1). The TWO-RRS method was found to have much better flexibility and high sensitivity than the single-wavelength method. In this paper, the interaction conditions were optimized. The affecting factors and characteristics of RRS for the interaction of DSS with CV were investigated and a sensitive method for the determination of trace amounts of DSS using the TWO-RRS method was developed. PMID:18674962

Hao, Xiu Li; Li, Nian Bing; Luo, Hong Qun

2009-01-01

63

Interaction between crystal violet and anionic surfactants at silica/water interface using evanescent wave-cavity ring-down absorption spectroscopy.  

PubMed

Evanescent wave-cavity ring-down spectroscopy (EW-CRDS) is employed to characterize micellization of anionic surfactants and the related capability of removing cationic substance off the silica surface. Crystal violet (CV(+)) cationic dye is used as a molecular probe to effectively determine critical hemimicelle concentration (HMC) of surfactants on the surface. The HMC results are 1×10(-2), 4×10(-3), 8×10(-4), and 2.5×10(-4) mol/L for sodium sulfate salts with a carbon-chain length of C-10, C-12, C-14, and C-16, respectively. A stronger hydrophobic interaction results in a less concentration required to undergo micellization. The HMC values on the surface are about half of those in solution. When NaCl solution is added, the electrolyte helps reduce the electrostatic repulsion between the anionic sulfate heads to facilitate the surfactant aggregation, and thus, the subsequent HMC is reduced. Furthermore, the probable phase change for dye-surfactant interactions on the surface at the concentration below HMC is observed, and the desorption rates of CV(+) are measured as a function of concentration and carbon-chain length of surfactants above HMC. Given each surfactant concentration at its respective HMC, the corresponding desorption rates are along the order of C-12

Lin, Meng-Chen; Lin, King-Chuen

2012-08-01

64

Enhanced removal of methylene blue and methyl violet dyes from aqueous solution using a nanocomposite of hydrolyzed polyacrylamide grafted xanthan gum and incorporated nanosilica.  

PubMed

The synthesis and characterization of a novel nanocomposite is reported that was developed as an efficient adsorbent for the removal of toxic methylene blue (MB) and methyl violet (MV) from aqueous solution. The nanocomposite comprises hydrolyzed polyacrylamide grafted onto xanthan gum as well as incorporated nanosilica. The synthesis exploits the saponification of the grafted polyacrylamide and the in situ formation of nanoscale SiO2 by a sol-gel reaction, in which the biopolymer matrix promotes the silica polymerization and therefore acts as a novel template for nanosilica formation. The detailed investigation of the kinetics and the adsorption isotherms of MB and MV from aqueous solution showed that the dyes adsorb rapidly, in accordance with a pseudo-second-order kinetics and a Langmuir adsorption isotherm. The entropy driven process was furthermore found to strongly depend on the point of zero charge (pzc) of the adsorbent. The remarkably high adsorption capacity of dyes on the nanocomposites (efficiency of MB removal, 99.4%; maximum specific removal Qmax, 497.5 mg g(-1); and efficiency of MV removal, 99.1%; Qmax, 378.8 mg g(-1)) is rationalized on the basis of H-bonding interactions as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules. Because of the excellent regeneration capacity the nanocomposites are considered interesting materials for the uptake of, for instance, toxic dyes from wastewater. PMID:24579659

Ghorai, Soumitra; Sarkar, Asish; Raoufi, Mohammad; Panda, Asit Baran; Schönherr, Holger; Pal, Sagar

2014-04-01

65

Imazaquin adsorbed on pillared clay and crystal violet-montmorillonite complexes for reduced leaching in soil.  

PubMed

Ground water pollution due to herbicide leaching has become a serious environmental problem. Imazaquin [2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)quinoline-3-carboxylic acid] is an herbicide used to control broadleaf weeds in legume crops. Imazaquin is negatively charged at the basic pH of calcareous soils and exhibits high leaching potential in soils. Our aim was to design formulation of imazaquin to reduce herbicide leaching. Imazaquin sorption on pillared clay (PC) and crystal violet (CV)-montmorillonite complexes was studied. The CV-montmorillonite complexes become positively charged with adsorption of CV above the cation exchange capacity (CEC) of montmorillonite, and thus can sorb imazaquin. The Langmuir equation provides a good fit to isotherms of imazaquin sorption on PC and CV-montmorillonite complexes, but for charged complexes an equation that combines electrostatics with specific binding was preferred. Maximal imazaquin sorption was 17.3 mmol kg-1 for PC and 22.2 mmol kg-1 for CV-montmorillonite complexes. The extents of imazaquin desorption into water were 21% for PC and 5% for CV-clay complexes. The presence of anions decreased imazaquin sorption on both sorbents in the sequence phosphate > acetate > sulfate. Reduction of imazaquin sorption by the anions and the extent of its desorption in electrolyte solutions were higher for PC than for CV-clay complexes. Leaching of imazaquin from CV-montmorillonite formulations through soil (Rhodoxeralf) columns was two times less than from PC formulations and four times less than that of technical imazaquin. The CV-montmorillonite complexes at a loading above the CEC appear to be suitable for preparation of organo-clay-imazaquin formulations that may reduce herbicide leaching significantly. PMID:12371183

Polubesova, Tamara; Nir, Shlomo; Gerstl, Zev; Borisover, Mikhail; Rubin, Baruch

2002-01-01

66

Fabrication of a network structure SERS substrate and the application in ultra-sensitive crystal violet detection  

NASA Astrophysics Data System (ADS)

A network structure surface-enhanced Raman scattering (SERS)-active substrate is fabricated by adding Ag sol dropwise on adhesive tape. Scanning electron microscope (SEM) is employed to characterize the structure of the as-prepared substrate. The substrate shows great SERS enhancement ability and good uniformity by using p-aminothiophenol (PATP) as probe molecules. The detection of crystal violet (CV) in aqueous solution is demonstrated, and the detection limit is as low as 10-12 M with the aid of the substrate. The results indicate that the proposed method is a potential approach for the fabrication of SERS substrates.

Tan, En-zhong; Yin, Peng-gang; Guo, Lin

2013-09-01

67

Adsorption kinetics of methyl violet onto perlite  

Microsoft Academic Search

This study examines adsorption kinetics and activation parameters of methyl violet on perlite. The effect of process parameters like contact time, concentration of dye, temperature and pH on the extent of methyl violet adsorption from solution has been investigated. Results of the kinetic studies show that the adsorption reaction is first order with respect to dye solution concentration with activation

Mehmet Do?an; Mahir Alkan

2003-01-01

68

Surfactant enhanced reorientation in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

We show that a large nonlinearity in dye-doped liquid crystals is obtained for extremely low input light intensity, of the order of a few tens of ? W/cm2 and that it is mediated by the action of the photo-induced voltage on the specific surface coupling agent.

Petrossian, A.; Residori, S.

2002-10-01

69

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

NASA Astrophysics Data System (ADS)

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.

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

2002-02-01

70

Influence of anthraquinone dyes on optical reorientation of nematic liquid crystals.  

PubMed

Optical reorientation measurements in dye-doped nematic liquid crystals are reported. The dye-induced optical torque exceeds significantly the normal optical torque for all anthraquinone dyes investigated. With one of the dyes, optical Freedericksz transition in a planar layer is demonstrated. PMID:19798127

Jánossy, I; Kósa, T

1992-09-01

71

Crystal violet as an i-motif structure probe for reversible and label-free pH-driven electrochemical switch.  

PubMed

A simple pH-induced electrochemical switch based on an i-motif structure is developed by using crystal violet as a selective electrochemical probe for the i-motif structure. Thiol-modified cytosine-rich single-strand oligonucleotide (C-rich ssDNA) can be self-assembled on the gold electrode surface via gold-sulfur interaction. Crystal violet is employed as an electrochemical probe for the i-motif structure because of its capability of binding with the i-motif structure through an end-stacking mode. In acidic aqueous solution, crystal violet may approach the electrode surface owing to the formation of the i-motif structure, resulting in an obvious signal, so-called "ON" state. Whereas in neutral or basic aqueous solution, the i-motif structure unfolds to dissociative single strand, which causes crystal violet to leave from the electrode surface, and a weak signal is obtained, so-called "OFF" state. In addition, in the range of pH 4.6-7.3, the increase in current has a good linear relationship (R=0.989) with pH value in the testing solutions. This pH-driven electrochemical switch has the advantages of simplicity, sensitivity, high selectivity, and good reversibility. Furthermore, it provides a possible platform for pH measurement. PMID:24699211

Zhang, Xi Yuan; Luo, Hong Qun; Li, Nian Bing

2014-06-15

72

A sensitive and simple method for the determination of chondroitin sulfate a with crystal violet by resonance rayleigh scattering technique.  

PubMed

Resonance Rayleigh scattering (RRS) spectra resulting from interaction between chondroitin sulfate A (CSA) and crystal violet (CV) have been investigated and applied to the determination of CSA. Though the intensity of RRS has proved very weak for CSA and CV, respectively, it can be greatly enhanced when both interact and form a supramolecular complex. A new RRS spectrum appears with a maximum scattering peak at 328 nm. In this paper, the optimum conditions of the interaction, influencing factors, and the relationship between the relative intensity of RRS (DeltaI) and the concentration of CSA have been thoroughly investigated. A new method of determination for the trace amount of CSA has been developed, which combines a simple procedure, high sensitivity, and a low detection limit of 4.8 ng/mL. It has been applied with satisfactory results to the determination of CSA in CSA injection samples and synthetic samples. PMID:16143959

Li, Taishan; Liu, Shaopu; Liu, Zhongfang; Hu, Xiaoli

2005-09-01

73

Resonance Rayleigh scattering study of interaction of hyaluronic acid with ethyl violet dye and its analytical application.  

PubMed

In near weak acid to neutral medium, ethyl violet (EV) can react rapidly with hyaluronic acid (HA) to form a complex, which results in a significant enhancement of resonance Rayleigh scattering (RRS) and an appearance of a new spectrum, and the scattering wavelengths appear at 231, 274, 326, 498 and 640 nm. The maximum scattering wavelength appears at 326 nm. The RRS intensity is directly proportional to the concentration of HA in the range of 0.4-48.0 microg mL(-1). A new method for the determination of trace amounts of HA based on the RRS method has been developed. The method exhibits high sensitivity, and the detection limit for HA is 9.6 x 10(-2) microg mL(-1). This method was applied for determining HA in eyedrops and in sodium hyaluronate injection samples with satisfactory results. Furthermore, the enhancement reasons of RRS and the relationship between RRS spectral characteristics of the HA-EV complex and its absorption spectrum have been discussed. PMID:15921906

Luo, Hong Qun; Li, Nian Bing; Liu, Shao Pu

2006-01-15

74

Molecular Interactions in Monolayers omicrf Azo Dye\\/Liquid Crystal Mixtures at Interfaces  

Microsoft Academic Search

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

D. Bauman; A. Plóciennik; K. Inglot

2009-01-01

75

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

76

Effect of organic dyes on the dielectric properties of KH 2 PO 4 crystals  

Microsoft Academic Search

The effect of organic dyes on the dielectric properties of KH2PO4 (KDP) crystals is studied over a wide range of temperatures. The dielectric properties of KDP crystals doped with molecules\\u000a of the Chicago Sky Blue and Amaranth organic dyes are investigated for the first time. The dye molecules can be incorporated\\u000a into the crystal lattice of KDP and selectively paint

S. V. Grabovskii; I. V. Shnaidshtein; B. A. Strukov

2003-01-01

77

Removal of triphenylmethane dyes by bacterial consortium.  

PubMed

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

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

2012-01-01

78

Fast optical recording in dye-doped liquid crystals.  

PubMed

Light-induced director reorientation in dye-doped nematic liquid crystals was recently reported to be an efficient method of writing permanent holographic gratings with high sensitivity [Phys. Rev. Lett. 82, 1855 (1999)]. We report the achievement of stable director reorientation in the same materials by means of a single 4-ns pulse of the second harmonic of a Nd:YAG laser. Fast recording of high-resolution holographic gratings (more than 500 lines/mm) can be obtained with an energy density as low as 7x10(-3)J /cm(2) . PMID:18073941

Lucchetti, L; Simoni, F; Reznikov, Y

1999-08-01

79

Crystallization control of organic dyes in self-organized microdomes  

NASA Astrophysics Data System (ADS)

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.

Karthaus, Olaf; Kaga, Kazuaki; Kageyama, Hiroaki

2004-09-01

80

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

PubMed Central

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.

Coban, Ahmet Yilmaz

2014-01-01

81

Application of ionic liquid-based microwave-assisted extraction of malachite green and crystal violet from water samples.  

PubMed

A simple, environment friendly and efficient technique, ionic liquid-based microwave-assisted extraction was first used to determine malachite green and crystal violet (CV) from water samples coupled to HPLC. The key parameters influencing extraction efficiency were investigated, such as the type of ionic liquids, the volume of ionic liquid, extraction time, and so on. Under the optimum conditions, good reproducibility of the extraction performance was obtained (RSD, 1.0% for malachite green (MG) and 5.9% for CV, n = 5). Good linearity (0.10-25 ?g L(-1)) was observed with correlation coefficients between 0.9991 and 0.9964. The detection limits of MG and CV were 0.080 and 0.030 ?g L(-1), respectively. The proposed method had been successfully applied to determine MG and CV in real water samples with recoveries ranging from 95.4 to 102.8%. Compared with the previous technologies, the proposed method required less extraction time (2 min), and provided lower detection limits and higher enrichment factors. Moreover, there were no volatile and hazardous organic solvents released. Based on these simple, environment friendly, rapid, and highly efficient results, the proposed approach provides a new and promising alternative for simultaneously extracting trace amounts of MG and CV from water. PMID:23436763

Gao, Zhanqi; Liu, Tingfeng; Yan, Xiaoju; Sun, Cheng; He, Huan; Yang, Shaogui

2013-03-01

82

Broadband near ultra violet sensitization of 1 ?m luminescence in Yb3+-doped CeO2 crystal  

NASA Astrophysics Data System (ADS)

Broadband spectral modification of near ultra violet (UV) light to infra-red (IR) light is investigated in Yb3+-doped CeO2 polycrystalline ceramics sintered in different atmospheres (air, oxygen, and 95%N2-5%H2). The intense Yb3+ photoluminescence (PL) peaked at 970 nm was observed by the UV excitation at around 390 nm in the samples except those sintered under N2-H2. A broad photoluminescence excitation (PLE) band of Yb3+ luminescence peaked at 390 nm corresponds to the absorption band and the photocurrent excitation band in the non-doped CeO2 crystal, which are also in accordance with the PLE band of Eu3+ luminescence in the Eu3+-doped CeO2. Judging from these results, the PLE band is attributed to the charge transfer (CT) band from O2- to Ce4+, but not to the CT from O2- to Yb3+. From the sintering atmosphere dependence of the PL and PLE, we found that the oxygen vacancies and Ce3+ impurities are not responsible for the 390 nm-absorption band but they work as a quenching center for the Yb3+ luminescence.

Ueda, Jumpei; Tanabe, Setsuhisa

2011-10-01

83

Biodegradation of p-nitrophenol sorbed onto crystal violet-modified organoclay by Arthrobacter sp. 4H?.  

PubMed

Organoclays are effective sorbents for removal of organic contaminants from water, but their regeneration capacity limits their practical use as a biotechnological process for bioremediation. Here, the sorption of p-nitrophenol (PNP) to crystal violet (CV)-modified montmorillonite and its biodegradation by the bacterium Arthrobacter sp. 4H? were studied in a batch aqueous system. The degree of PNP sorption was dependent on the degree of CV modification (loaded at 80 % or 100 % of the clay's cation-exchange capacity-CVM80 and CVM100, respectively). CV sorption to the clay reduced its toxicity to bacteria. PNP at an initial concentration of 0.72 mM was degraded at rates of 65 % and 42 % in CVM80 and CVM100 suspensions, respectively. Both free and CV-clay-adsorbed PNP concentrations were reduced by the bacteria at rates proportional to the degree of CV modification. Three successive cycles of PNP reloading-degradation in the organoclay suspension demonstrated the potential of this matrix's regeneration and reuse toward maximal removal efficiency of organic pollutants. PMID:23715856

Masaphy, Segula; Zohar, Shay; Jander-Shagug, Gurinaz

2014-02-01

84

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

85

The molecular ordering phenomenon in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

The experimental results of this work point out the role of the guest dye molecules in the molecular ordering of nematic liquid crystals. We have discussed the changes in the energies of interactions between rod-like nematic molecules and anthraquinone dye by considering the presence of steric and dipole-dipole interactions in the dye-doped system. The concentration of the dye plays an important role in the determination of molecular ordering in such dye-doped systems. Below a certain concentration of dye (known as the critical concentration), where the interaction between the dye molecules can be neglected, the addition of dye molecules introduces some disorder into the system in the form of domain formation. Above this critical concentration, this disorder is small.

Yadav, Satya Prakash; Pandey, Kamal Kumar; Misra, Abhishek Kumar; Tripathi, Pankaj Kumar; Manohar, Rajiv

2011-03-01

86

Optical phase conjugation in dye-doped nematic liquid crystal  

NASA Astrophysics Data System (ADS)

Optical phase conjugation in dye-doped nematic liquid crystals has been obtained with 532 nm radiation from a cw doubled YAG laser of total power of 50 mW. A 40° twisted nematic cell configuration has been used. The degenerate four-wave mixing (DFWM) experiment allowed for measurements of build-up time of phase conjugate signal and phase conjugate reflectivity as a function of input beam intensities and grating spacing. The PC reflectivities reached 2.6% and build-up times were of the order of 200 ms. The origin of the phase conjugate signal is linked with photoconductivity enhanced dynamic holographic refractive index grating formation observed in this and other similar systems.

Miniewicz, Andrzej; Bartkiewicz, Stanis? Aw; Parka, Janusz

1998-04-01

87

A nano-patterned photonic crystal laser with a dye-doped liquid crystal  

NASA Astrophysics Data System (ADS)

Covering a nano-patterned titanium dioxide photonic crystal (PC) within a well-oriented film of dye-doped liquid crystal (LC), a distributed feedback laser is constructed whereby the emission characteristics can be manipulated in-situ using an electric field. This hybrid organic-inorganic structure permits simultaneous selectivity of both the beam pattern and laser wavelength by electrical addressing of the LC director. In addition, laser emission is obtained both in the plane and normal to the PC. Along with experimental data, a theoretical model is presented that is based upon an approximate calculation of the band structure of this birefringent, tuneable laser device.

Ko, Doo-Hyun; Morris, Stephen M.; Lorenz, Alexander; Castles, Flynn; Butt, Haider; Gardiner, Damian J.; Qasim, Malik M.; Wallikewitz, Bodo; Hands, Philip J. W.; Wilkinson, Timothy D.; Amaratunga, Gehan A. J.; Coles, Harry J.; Friend, Richard H.

2013-07-01

88

Crystallization of fused silica surfaces by ultra-violet laser irradiation  

NASA Astrophysics Data System (ADS)

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), ?-quartz (111), and ?-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.

Hirata, Kazuya; Haraguchi, Koshi

2012-07-01

89

Room Temperature Single-Photon Source: Single-Dye Molecule Fluorescence in Liquid Crystal Host  

SciTech Connect

OAK-(B204)We report on new approaches toward an implementation of an efficient, room temperature, deterministically polarized, single-photon source (SPS) on demand-a key hardware element for quantum information and quantum communication. Operation of a room temperature SPS is demonstrated via photon antibunching in the fluorescence from single terrylene-dye molecules embedded in a cholesteric liquid crystal host. Using oxygen-depleted liquid crystal hosts, dye-bleaching was avoided over the course of more than 1 h of continuous 532-nm excitation. Liquid crystal hosts (including liquid crystal oligomers/polymers) permit further increase of the efficiency of the source: (1) by aligning the dye molecules along a direction preferable for the maximum excitation efficiency; (2) by tuning a one-dimensional (1-D) photonic-band-gap microcavity of planar-aligned cholesteric (chiral nematic) liquid crystal layer to the dye fluorescence band.

Lukishova, S.G.; Schmid, A.W.; McNamara, A.J.; Boyd, R.W.; Stroud, C.R.Jr.

2003-12-31

90

Light emission from dye-doped cholesteric liquid crystals at oblique angles: Simulation and experiment.  

PubMed

Dye-doped cholesteric liquid crystals with a helical pitch of the order of a wavelength have a strong effect on the fluorescence properties of dye molecules. This is a promising system for realizing tunable lasers at low cost. We apply a plane wave model to simulate the spontaneous emission from a layer of cholesteric liquid crystal. We simulate the spectral and angle dependence and the polarization of the emitted light as a function of the order parameter of the dye in the liquid crystal. Measurements of the angle dependent emission spectra and polarization are in good agreement with the simulations. PMID:22680487

Penninck, L; Beeckman, J; De Visschere, P; Neyts, K

2012-04-01

91

Linear and nonlinear optical properties of dye-doped KDP crystals: Effect of thermal treatment  

NASA Astrophysics Data System (ADS)

Potassium dihydrogen phosphate crystals (KDP, KH 2PO 4) doped with the organic xylenol orange (XO) dye are grown, the XO concentration in the crystal matrix is about 10 ppm. The spectral and luminescent properties of nominally pure, dye-doped and dye-doped/annealed at 150 °C crystals (KDP, KDP:XO and KDP:XO an) were measured. The annealing temperature effect on the degree of dye protonation in the crystal matrix is established. Analysis of the IR-absorption spectra reveals a strong interaction between the incorporated dye molecules and the hydrogen subsystem of the matrix. The nonlinear optical (NLO) properties of KDP, KDP:XO and KDP:XO an crystals are studied within the self-action effect of picosecond laser pulses at 532 nm. The mechanism of photoinduced bleaching and the effects of laser beam self-focusing (in KDP) and self-defocusing (in KDP:XO and KDP:XO an) are supposed to be due to resonance excitation of the subsystems of intrinsic defects and dye molecules, correspondingly. For KDP:XO an it is shown that thermal annealing of intrinsic crystal defects leads to domination of more effective NLO response of the subsystem of dye molecules that is correlated with photoluminescence data.

Pritula, I.; Gayvoronsky, V.; Gromov, Yu.; Kopylovsky, M.; Kolybaeva, M.; Puzikov, V.; Kosinova, A.; Savvin, Yu.; Velikhov, Yu.; Levchenko, A.

2009-03-01

92

Molecular Interactions in Monolayers ?f Azo Dye/Liquid Crystal Mixtures at Interfaces  

NASA Astrophysics Data System (ADS)

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.

Bauman, D.; P?óciennik, A.; Inglot, K.

2009-08-01

93

Alignment-to-polarization projection in dye-doped nematic liquid crystal microlasers.  

PubMed

We report a dye-doped nematic liquid crystal microlaser that allows the two-dimensional alignment of the liquid crystal to be projected directly on the output polarization of the laser beam. The laser cavity is composed of a pair of dielectric multilayers sandwiching a dye-doped nematic liquid crystal with patterned alignment, and exploits the fact that the resonance modes in such systems are split into two orthogonally polarized modes experiencing either the extraordinary or ordinary refractive index of the liquid crystal. Azimuthally polarized lasing is demonstrated using a concentrically aligned liquid crystal layer. PMID:20588382

Yoshida, Hiroyuki; Tagashira, Kenji; Kumagai, Takayuki; Fujii, Akihiko; Ozaki, Masanori

2010-06-01

94

Nonlinear optical studies of dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

In this dissertation, nonlinear optical studies were carried out on dye-doped nematic liquid crystal cells. The main objectives of the studies were to distinguish and characterize the several processes that can lead to the formation of dynamic gratings of different types in the samples, and to study the photorefractive and the orientational responses of these samples. Asymmetric two-beam coupling experiments revealed that the induced grating was a photorefractive phase grating created by the nematic director reorientation within the plane of incidence. The dynamics of the beam coupling showed that two different mechanisms with different temporal responses were involved. The grating translation technique identified both gratings as pure photorefractive index gratings with phase shifts of ˜pi/2 between the grating and the interference pattern. In addition, the dynamical behavior of the grating formation, obtained from forced light scattering experiments, also exhibited a two-time constant response. The dynamical behaviors of the build-up and decay of the photocurrent were investigated. The two dynamics exhibited both a two-time constant behavior, suggesting that the origin of the two-time constant dynamics observed in the two-beam coupling and the forced light scattering experiments resides in the process of photo-charge generation. All the samples showed a threshold behavior with respect to the magnitude of the applied electric field. This threshold behavior was observed both in forced light scattering experiments and polarization holographic experiments. We believe that the origin of this threshold lies in the process of photogeneration, which was found to exhibit the same threshold behavior at the same value of the applied voltage. An asymmetry of the photorefractive gain with respect to the direction of the applied electric field was observed in samples with high dye concentration. This was attributed to the beam fanning effect, which has also been observed in other high-gain photorefractive materials. The conductivity and the photoconductivity of the samples were measured. The photocurrent was found to increase linearly with the illumination power, which indicates that the charge carrier recombination rate is proportional to the carrier density. The measured electrical conductivity was found to be proportional to the square root of the dye concentration, confirming the validity of the proposed charge-injection model. (Abstract shortened by UMI.)

Klysubun, Prapong

95

A fiber-optic violet sensor by using the surface grating formed by a photosensitive hybrid liquid crystal film on side-polished fiber  

NASA Astrophysics Data System (ADS)

A fiber-optic violet sensor is demonstrated by using the surface grating formed by a photosensitive liquid crystal (LC) hybrid film on the flat area of side-polished fiber (SPF). The surface grating is constructed through a periodic intensity illuminating the hybrid LC film, where the periodic intensity is created by a phase mask through which the violet light passes. Experiment shows that a loss peak appears in the transmission spectrum between 1520 and 1620 nm, and this loss peak shifts toward shorter wavelength as the 405 nm light power increases. The wavelength shift of the peak shows very good linearity with the irradiation power between 30 and 80 mW cm-2. The very high sensitivity of the light power sensor is measured to be 1.154 nm (mW cm-2)-1, which implies that the minimum change of power intensity that can be detected is 0.866 µW cm-2 for this sensor under the limited wavelength resolution of 0.001 nm of the optical spectrum analyzer. For UV light, much higher sensitivity will be further obtained, as the LC hybrid is more sensitive to UV light than to violet light.

Yu, Jianhui; Li, Haozhi; Hsiao, V. K.; Liu, Weiping; Tang, Jieyuan; Zhai, Yanfang; Du, Yao; Zhang, Jun; Xiao, Yi; Chen, Zhe

2013-09-01

96

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

SciTech Connect

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.

Parkinson, Bruce

2010-06-04

97

Incident angle and polarization effects on the dye-doped cholesteric liquid crystal laser  

Microsoft Academic Search

Polarization effect of the pulsed pumping laser on the lasing characteristics of the dye-doped right-handed cholesteric liquid crystal (CLC) is studied at different incident angles. At a small incident angle (

Yuhua Huang; Ying Zhou; Qi Hong; Alexandra Rapaport; Michael Bass; Shin-Tson Wu

2006-01-01

98

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

ERIC Educational Resources Information Center

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)

Sadlej-Sosnowska, Nina

1980-01-01

99

Trityl Dyes Patent Blue V and Brilliant Blue G - Clinical Relevance and in vitro Analysis of the Function of the Outer Blood-Retinal Barrier  

Microsoft Academic Search

The use of vital dyes during vitrectomy allows easier removal of less recognizable structures like epiretinal membranes or the internal limiting membrane (ILM). In recent years, numerous studies have investigated the use of indocyanine green (ICG), trypan blue (Membrane Blue™), triamcinolone, autologous blood and presently trityl dyes such as patent blue V (PBV, Blueron™), crystal violet and brilliant blue G

S. Mennel; C. Meyer; J. Schmidt; S. Kaempf; G. Thumann

2008-01-01

100

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

PubMed

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

Kundu, Sudarshan; Kang, Shin-Woong

2013-12-16

101

Nonlinear refractive index of some anthraquinone dyes in 1294-1b liquid crystal  

NASA Astrophysics Data System (ADS)

Third order nonlinear refractive index of three anthraquinone dyes, i.e., Solvent Blue 59, Solvent Blue 35 and Solvent Green 3 doped in 1294-1b nematic liquid crystal (NLC) were studied by the single beam Z-scan technique using a continuous-wave He-Ne laser at 632.8 nm. The negative nonlinear refractive index (n 2) in the order of 10 - 5 cm 2/w for all samples was obtained. We believe that, this large nonlinearity is owing to Janossy effect and the difference in the nonlinear refractive index of our dyes can be described by the structures of dyes and the interactions between dyes and 1294-1b molecules. So as to understand the effect of dye structure on nonlinearity enhancement, the dichroic ratio of these dyes in 1294-1b was measured using polarized spectroscopy.

Milanchian, K.; Abdi, E.; Tajalli, H.; Ahmadi K., S.; Zakerhamidi, M. S.

2012-03-01

102

Lowering the Lasing Threshold by Introducing Cholesteric Liquid Crystal Films to Dye-Doped Cholesteric Liquid Crystal Cell Surfaces  

Microsoft Academic Search

The effect of the introduction of polymer cholesteric liquid crystal (PCLC) films on the threshold of dye-doped cholesteric liquid crystal (CLC) distributed feedback (DFB) cavity lasing has been investigated. A PCLC film used to reflect a pump beam brings about the efficient use of incident energy, whereas a PCLC film used to reflect the emission contributes to amplifying the stimulated

Kazuhiro Amemiya; Myoung Hoon Song; Yoichi Takanishi; Ken Ishikawa; Suzushi Nishimura; Takehiro Toyooka; Hideo Takezoe

2005-01-01

103

Random lasers in dye-doped polymer-dispersed liquid crystals containing silver nanoparticles  

NASA Astrophysics Data System (ADS)

We report on the observation of random lasers for the first time in dye-doped polymer-dispersed liquid crystals (PDLCs) containing nano-sized liquid crystal droplets and silver nanoparticles. The dye-doped polymer-dispersed liquid crystal containing silver nanoparticles film is exposed by a collimated 532 nm Nd: YAG (yttrium aluminum garnet) laser beam, so that it is quickly cured. Under the excitation of a frequency-doubled Nd: YAG (yttrium aluminum garnet) laser operating at a wavelength of 532 nm, random lasing from dye-doped PDLCs containing Ag nanoparticles is observed as a result of cooperative effect due to light scattering of nano-sized liquid crystal droplets and the local field enhancement capabilities around silver nanoparticles. We show that the threshold of the random lasing is about 0.95 ?J/pulse which is lower than the lasing threshold of dye-doped polymer-dispersed liquid crystals containing nano-sized liquid crystal droplets. The linewidth of the lasing peaks is shown to be 0.2 nm. We also propose a possible mechanism to explain the random lasing from dye-doped polymer-dispersed liquid crystals containing silver nanoparticles.

Li, LongWu; Deng, LuoGen

2012-12-01

104

Spectral properties of self-assembled polystyrene nanospheres photonic crystals doped with luminescent dyes  

NASA Astrophysics Data System (ADS)

Three-dimensional ordered photonic crystals have been fabricated on solid substrates with a self-assembling method starting from a suspension of dye-doped polymeric nanospheres in water. These photonic crystals showed angle-dependent stop band for light transmission and, correspondingly, Bragg reflection peak due to the photonic crystal lattice. Polystyrene nanoparticles of 306 nm and 288 nm diameter, respectively in the case of the Rhodamine B and Fluored dye, were used to obtain self-assembled photonic crystals. They show 40% reflectance at 610 nm for Rhodamine B and 35% reflectance at 574 nm for Fluored doped materials. The size of the spheres calculated by Bragg's law are in good agreement with those evaluated by scanning electron microscopy (SEM). The appropriate choice of sphere diameters results in an overlap between the photonic stop-band and the dye emission spectrum. The photonic crystals showed angle-dependent suppression of spontaneous emission of the dye in the wavelength range of the photonic stop band and enhancement near the band edge. In reflection geometries, spectral narrowing and directional emission, all indicative of stimulated emission, were observed from the active photonic crystal matrix. The results of laser induced emission studies on the dye doped photonic crystals are presented.

Yadav, A.; De Angelis, R.; Casalboni, M.; De Matteis, F.; Prosposito, P.; Nanni, F.; Cacciotti, I.

2013-06-01

105

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

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.

Anass, M. Abbas; G. Ahmed, Hussain

2013-01-01

106

Nonlinear optical organic co-crystals of merocyanine dyes and phenolic derivatives with short hydrogen bonds  

Microsoft Academic Search

We investigated the co-crystallization of merocyanine dyes M (M: R–N+C5H4–CH?CH–C6H4O?, M1: R=CH3, M2: R=HO–CH2–CH2–) with phenolic and aniline derivatives and show that the short or very short hydrogen bond between the two phenolic oxygen atoms which lead to a self-assembly of the M dyes and phenol derivatives is the key steering force for the co-crystallization process. The co-crystal formation was

Christian Bosshard; Feng Pan; Man Shing Wong; Sabine Manetta; Rolf Spreiter; Chengzhi Cai; Peter Günter; Volker Gramlich

1999-01-01

107

Dichroic dye-dependent studies in guest-host polymer-dispersed liquid crystal films  

NASA Astrophysics Data System (ADS)

Guest-host polymer-dispersed liquid crystal (GHPDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and dichroic dye (anthraquinone blue) by polymerization-induced phase separation (PIPS) technique. Non-ionic dichroic dye (1%, 2% and 4% wt./wt. ratio) was taken as guest in PDLC host. Polarizing microscopy shows that in the absence of electric field, liquid crystal (LC) droplets in polymer matrix mainly exhibit bipolar configuration, however, relatively at higher field, maltese-type crosses were observed. Our results show that ?1% dye-doped PDLC film shows better transmission and faster response times over pure polymer-dispersed nematic liquid crystal (PDNLC) and higher concentrated (2% and 4%) GHPDLC films.

Malik, Praveen; Raina, K. K.

2010-01-01

108

Dye-doped cholesteric-liquid-crystal room-temperature single-photon source  

SciTech Connect

Fluorescence antibunching from single terrylene molecules embedded in a cholesteric-liquid-crystal host is used to demonstrate operation of a room-temperature single-photon source. One-dimensional (1-D) photonic-band-gap microcavities in planar-aligned cholesteric liquid crystals with band gaps from visible to near-infrared spectral regions are fabricated. Liquid-crystal hosts (including liquid crystal oligomers and polymers) increase the source efficiency, firstly, by aligning the dye molecules along the direction preferable for maximum excitation efficiency (deterministic molecular alignment provides deterministically polarized output photons), secondly, by tuning the 1-D photonic-band-gap microcavity to the dye fluorescence band and thirdly, by protecting the dye molecules from quenchers, such as oxygen.

Lukishova, S.G.; Schmid, A.W.; Supranowitz, C.M.; Lippa, N.; McNamara, A.J.; Boyd, R.W.; Stroud, Jr., C.R.

2004-06-15

109

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

NASA Astrophysics Data System (ADS)

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.

Sefero?lu, Zeynel; Yalç?n, Ergin; Babür, Banu; Sefero?lu, Nurgül; Hökelek, Tuncer; Y?lmaz, Ebru; ?ahin, Ertan

2013-09-01

110

Luminescent dye-doped KAP nanorods obtained by template assisted crystallization.  

PubMed

Luminescent nanorods of potassium acid phthalate (KAP) doped with rhodamine 6G (Rh 6G) dye molecules were grown by template assisted crystallization. Pores with diameters ranging from tens of nanometers to few micrometers were obtained in polycarbonate foils after heavy-ion irradiation and subsequent chemical etching of the damage trails along the ion trajectories. Crystallization from solution was employed for filling of the pores with the dye-doped KAP rods. These nanostructures were characterized using scanning electron microscopy, optical absorption spectroscopy and photoluminescence detection. X-ray diffraction was used for structural analysis. The luminescence of the dye-doped rods undergoes a redshift when the diameter of the structures decreases. This shift is probably caused by increasing dye concentration in the rods with decreasing pore diameter. The luminescence originating from the Rh 6G presence is up-converted due to the second-harmonic generation in KAP. PMID:21780390

Enculescu, M; Neumann, R

2011-05-01

111

Change of Birefringence in Dye-Doped Nematic Liquid Crystals Under Laser Illumination  

NASA Astrophysics Data System (ADS)

Birefringence property of E7 nematic liquid crystal is investigated via voltage dependent transmittance spectrums. Measurements are performed at wavelength 632.8 nm, which is the absorbance peak of our sample including anthraquinone derivative Disperse Blue 14. Results of dye-doped samples are compared with those undoped for dark and laser illuminated cases. It was observed that birefringence is dependent on laser illumination for dye-doped samples, up to a threshold voltage after which it is constant.

San, S. Eren; Köysal, Oðuz; Özder, Serhat; Ecevýt, F. Necatý

2003-07-01

112

Large deuterium isotope effect in the optical nonlinearity of dye-doped liquid crystals.  

PubMed

Deuterium-hydrogen isotopic substitution was found to approximately double the magnitude of the giant optical nonlinearity of dye-doped nematic liquid crystals arising from photoinduced molecular reorientation. In accordance with the predictions of our model, this doubling is well correlated with the increase in a characteristic decay time of the electronically excited dye anisotropy, as measured with time-resolved fluorescence. A similar isotopic effect is predicted for the optical Kerr nonlinearity of dyed isotropic liquids. PMID:11800945

Kreuzer, M; Hanisch, F; Eidenschink, R; Paparo, D; Marrucci, L

2002-01-01

113

Diffusion of photoexcited azo dye in a liquid-crystal host.  

PubMed

Dynamic holograms are created and studied in a D2 azo-dye-doped nematic liquid crystal. The dependence of diffraction on the excitation and probe polarizations is observed. The efficiency of excitation and the corresponding relaxation time depend also on the period and orientation of the light-interference pattern with respect to the initial molecular orientation. The excitation and diffusion of dye molecules are suggested to be the origin of these phenomena. PMID:18087323

Saad, B; Denariez-Roberge, M M; Galstyan, T V

1998-01-01

114

Large Deuterium Isotope Effect in the Optical Nonlinearity of Dye-Doped Liquid Crystals  

NASA Astrophysics Data System (ADS)

Deuterium-hydrogen isotopic substitution was found to approximately double the magnitude of the giant optical nonlinearity of dye-doped nematic liquid crystals arising from photoinduced molecular reorientation. In accordance with the predictions of our model, this doubling is well correlated with the increase in a characteristic decay time of the electronically excited dye anisotropy, as measured with time-resolved fluorescence. A similar isotopic effect is predicted for the optical Kerr nonlinearity of dyed isotropic liquids.

Kreuzer, M.; Hanisch, F.; Eidenschink, R.; Paparo, D.; Marrucci, L.

2002-01-01

115

Surface plasmon-enhanced lasing in dye-doped cholesteric liquid crystals.  

PubMed

This study shows the results of a photonic band-edge laser using dye-doped cholesteric liquid crystals (CLCs) combined with silver (Ag) nanoparticles. When the Ag nanoparticle surface plasmon resonance wavelength matched the excitation source wavelength, the large optical fields provided by surface plasmons increased the fluorescence of dye molecules by enhancing the molecular excitation rate, achieving a low lasing threshold and high pumping efficiency. PMID:23037118

Shih, Cheng-Yu; Yeh, Hui-Chen

2012-08-27

116

Photo-patterning micro-mirror devices using azo dye-doped cholesteric liquid crystals  

Microsoft Academic Search

A simple method for fabricating patternable micro-mirror devices by photo-induced alignment of dye-doped cholesteric liquid crystal (CLC) is demonstrated. The CLC texture can be changed from random distribution to nearly perfect planar by the photo-excited adsorbed dyes. This structure transformation leads to a substantial reflectivity increase. Using this photo-patterning technique, one- and two-dimensional micro-mirror arrays which function as gratings are

Tsung-Hsien Lin; Yuhua Huang; Ying Zhou; Andy Y. Fuh; Shin-Tson Wu

2006-01-01

117

Position-Sensitive Cholesteric Liquid Crystal Dye Laser Covering a Full Visible Range  

Microsoft Academic Search

We fabricated a cholesteric-liquid-crystal distributed-feedback laser cell with spatial gradient structures not only of the helical pitch but also of the concentrations of two dyes. By utilizing the energy transfer between two dyes, lasing was achieved covering a full visible range from 470 to 670 nm continuously by translating the cell with respect to a pumping beam without changing the

Koji Sonoyama; Yoichi Takanishi; Ken Ishikawa; Hideo Takezoe

2007-01-01

118

Enhanced optical nonlinearities in some dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

The nonlinear refractive index of some pure and dye-doped nematic liquid crystals was measured and compared using extraordinary polarized light. The optical torque of the nematic liquid crystals was strongly enhanced by a small amount of dye impurities (Sudan Black B). This observation is found to be in good agreement with the Janossy model. The dependence of the enhancement factor on the nematic host structure was investigated. The sign of all nonlinear refractive indices were determined by the Z-scan technique.

Jafari, A.; Tajalli, H.; Ghanadzadeh, A.

2006-08-01

119

Influence of nematic liquid crystal with dye and cell construction parameters on dynamic holographic grating formation  

NASA Astrophysics Data System (ADS)

We have described the relation between LC parameters and induced diffraction gratings recorded by light intensity pattern in dye-doped nematic liquid crystals sandwiched between two coating glass plates covered with ITO conductive and polyimide orientation layers. In our investigations we used the LC cells containing planary oriented nematic mixtures (low-angle rubbing, tilt 1.5 - 2%) doped with the antraquinone dyes (0.1 - 1% w/w). Nematic liquid crystal mixtures with different electrooptical threshold, optical anisotropy, viscosity and conductivity have been investigated. The influence of resistivity, optical anisotropy of LC mixtures and polyimide layers on diffraction efficiency and other parameters have been discussed.

Parka, Janusz; Miniewicz, Andrzej; Januszko, A.; Reznikov, Yuri A.; Dabrowski, Roman S.; Stolarz, Zofia

2000-05-01

120

Surfactant-controlled light-induced reorientation in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

We show that a very large optical response is obtained in azo-dye doped nematic liquid crystals for low input light intensities (of the order of a few tens of ?W/cm2 and that this extreme sensitivity of the nematic film results from a combined action of the photoisomerization process of the azo-dye molecules and the light-induced changes of the anchoring energy. The liquid crystal reorientation can be controlled by changing the molecular length of the ionic surfactant which is used as anchoring agent.

Residori, Stefania; Petrosyan, Artyom

2004-09-01

121

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

NASA Astrophysics Data System (ADS)

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.

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

2008-04-01

122

Holographic grating formation in dye- and fullerene C60-doped nematic liquid-crystal film  

NASA Astrophysics Data System (ADS)

Transient and persistent holographic gratings have been observed in dye- and fullerene C60 -doped nematic liquid-crystal films. The nature and time evolution of the underlying mechanisms, such as space-charge field production, flows, and dielectric- and conductivity-induced torques, and the resultant director axis reorientation and refractive-index gratings are examined.

Khoo, I. C.

1995-10-01

123

Pattern-forming instability induced by light in pure and dye-doped nematic liquid crystals.  

PubMed

We study theoretically the instabilities induced by a linearly polarized ordinary light wave incident at a small oblique angle on a thin layer of homeotropically oriented nematic liquid crystal with special emphasis on the dye-doped case. The spatially periodic Hopf bifurcation that occurs as the secondary instability after the stationary Freedericksz transition is analyzed. PMID:12366136

Krimer, D O; Demeter, G; Kramer, L

2002-09-01

124

First-order optical Freedericksz transition in a dye-doped nematic liquid crystal.  

PubMed

A first-order optical Freedericksz transition in a nematic liquid crystal doped by a small quantity of a dichroic dye with negative dichroism is observed. The initial homeotropic state corresponds to maximum absorption for the linearly polarized incident beam, while reorientation reduces absorption increasing the optical torque: this process produces the positive feedback leading to the observed bistable behavior. PMID:23503246

Simoni, F; Lucchetta, D E; Lucchetti, L; Ong, H L; Serak, S V; Tabiryan, N

2013-03-15

125

All-optical steering of soliton waveguides in dye-doped liquid crystals  

NASA Astrophysics Data System (ADS)

Soliton induced waveguides can be all-optically readdressed in planar cells by modifying the molecular anchoring with an external light source. Using an elliptically shaped control beam we demonstrate refraction and total internal reflection of spatial solitons in dye-doped nematic liquid crystals.

Piccardi, A.; Assanto, G.; Lucchetti, L.; Simoni, F.

2008-10-01

126

Pattern-forming instability induced by light in pure and dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

We study theoretically the instabilities induced by a linearly polarized ordinary light wave incident at a small oblique angle on a thin layer of homeotropically oriented nematic liquid crystal with special emphasis on the dye-doped case. The spatially periodic Hopf bifurcation that occurs as the secondary instability after the stationary Freedericksz transition is analyzed.

Krimer, D. O.; Demeter, G.; Kramer, L.

2002-09-01

127

Monodomain Film Formation and Lasing in Dye-Doped Polymer Cholesteric Liquid Crystals  

Microsoft Academic Search

We have succeeded in fabricating monodomain polymer cholesteric liquid crystal (PCLC) films by spin coating a polymer solution onto glass substrates with polyimide coated and rubbed unidirectionally. The thickness and helical pitch were well characterized by controlling the rotational speed of the spin coater and the chiral unit content of the polymer solution, respectively. Lasing from dye-doped PCLC films utilizing

Takashi Ohta; Myoung Hoon Song; Yuko Tsunoda; Takaaki Nagata; Ki-Chul Shin; Fumito Araoka; Yoichi Takanishi; Ken Ishkawa; Junji Watanabe; Suzushi Nishimura; Takehiro Toyooka; Hideo Takezoe

2004-01-01

128

Lowering Threshold by Energy Transfer between Two Dyes in Cholesteric Liquid Crystal Distributed Feedback Lasers  

Microsoft Academic Search

Lowering lasing threshold based on the Förster-type energy transfer process has been studied in distributed feedback (DFB) lasers of cholesteric liquid crystals (CLCs) containing two dyes. We found that the lasing threshold in the energy transfer process was lowered to less than half of that in direct excitation processes. This effect is attributed to the suppression of self-absorption of a

Koji Sonoyama; Yoichi Takanishi; Ken Ishikawa; Hideo Takezoe

2008-01-01

129

Light-induced orientational effects in periodic photonic structures with pure and dye-doped nematic liquid crystal defects  

NASA Astrophysics Data System (ADS)

We theoretically study and compare the light-induced Fréedericksz transition and above-threshold reorientation in pure and dye-doped nematic liquid crystals embedded into periodic dielectric structures. The presence of optical defect modes is found to significantly alter the effective influence of dyes as compared to the standard case of liquid crystal films without periodic structure, which is due to the overall resonant absorption of the dye-doped liquid crystal layer. Both statics and dynamics are discussed. In particular, it is found that optical response time can be up to several orders of magnitude faster with pure liquid crystals than with dye-doped ones. Thermal effects caused by absorption of dyes are also investigated to gauge whether it may induce nematic-to-isotropic phase transition.

Miroshnichenko, Andrey E.; Brasselet, Etienne; Kivshar, Yuri S.

2008-11-01

130

Light-induced gliding of the easy orientation axis of a dye-doped nematic liquid crystal  

NASA Astrophysics Data System (ADS)

We studied the effect of light-induced gliding of the easy axis of dye-doped nematic liquid crystal on an aligning polymer surface. The observed drift of the easy axis is over tens of degrees and is caused by light-induced anisotropic adsorption and/or desorption of dye molecules on or from the aligning layer in the presence of light-induced bulk torque. We present a theoretical model that explains the experimental data in terms of the light-induced changes of the adsorbed dye molecules angular distribution due to their exchange with the dye molecules from the liquid crystal bulk.

Fedorenko, Denis; Slyusarenko, Kostyantyn; Ouskova, Elena; Reshetnyak, Victor; Ha, Kiryong; Karapinar, Ridvan; Reznikov, Yuriy

2008-06-01

131

Light-induced gliding of the easy orientation axis of a dye-doped nematic liquid crystal.  

PubMed

We studied the effect of light-induced gliding of the easy axis of dye-doped nematic liquid crystal on an aligning polymer surface. The observed drift of the easy axis is over tens of degrees and is caused by light-induced anisotropic adsorption and/or desorption of dye molecules on or from the aligning layer in the presence of light-induced bulk torque. We present a theoretical model that explains the experimental data in terms of the light-induced changes of the adsorbed dye molecules angular distribution due to their exchange with the dye molecules from the liquid crystal bulk. PMID:18643285

Fedorenko, Denis; Slyusarenko, Kostyantyn; Ouskova, Elena; Reshetnyak, Victor; Ha, KiRyong; Karapinar, Ridvan; Reznikov, Yuriy

2008-06-01

132

One- and biphotonic reorientational nonlinearities in dye-doped nematic and cholesteric liquid crystals  

NASA Astrophysics Data System (ADS)

This investigation elucidates one- and biphotonic reorientational nonlinearities in dye-doped nematic liquid crystals (DDNLCs) and dye-doped cholesteric liquid crystals (DDCLCs) using the Z-scan technique. Three cases-DDNLCs stimulated by one green beam polarized linearly parallel and perpendicular to the LC director and DDCLCs stimulated by one circularly polarized green beam-are considered without and with simultaneous stimulation by one linearly polarized red beam. Green-beam-induced dye reorientation through trans-cis isomerization and red-beam-induced suppression of dye reorientation by cis-trans back isomerization are responsible for the one- and biphotonic nonlinearities, respectively. The nonlinear refractive indices obtained herein are two orders of magnitude larger than those obtained elsewhere [Fuh et al., Opt. Exp. 13, 10634 (2005)]. The induced biphotonic nonlinearities can be modulated by controlling the intensity of the red beam in different ways due to the difference among the capabilities of the red beam to suppress the reorientation of the dyes and LCs in the three cases.

Yeh, H.-C.; Lin, H.-C.; Mo, T.-S.; Fuh, Andy Y.-G.; Huang, S.-Y.; Lee, C.-R.

2008-10-01

133

Dye-concentration-dependent lasing behaviors and spectral characteristics of cholesteric liquid crystals  

NASA Astrophysics Data System (ADS)

The laser behavior and spectral changes occurring in cholesteric liquid crystals with varying dye-doped concentrations were investigated when pumped at 532 nm. It was found that the long-wavelength band edge and the laser line exhibit a blue shift over 21 nm with increasing dye concentration. The circularly polarized fluorescence spectra were examined, and the location of the sense reversion of circular polarization was determined to coincide well with the discrete lasing lines. The blue shift can be ascribed to the decrease in average refractive index and pitch of the dye-doped cholesteric liquid crystals. The dependence of the slope efficiency and threshold energy on the dye concentration can be attributed to the shift in photonic stopband and the change in penetration depth of excitation. The temperature and incident angle of pumping beam also have a significant impact on the lasing properties. The optimal dye concentration is found to be 0.5 wt% at 30.5 °C with an incident angle of 10°. The laser emission located at 601.4 nm with slope efficiency of 4 % was achieved above the threshold energy of 14.3 ?J.

Wang, Zhongyang; Yang, Can; Li, Wensong; Chen, Lujian; Wang, Xiaozhong; Cai, Zhiping

2014-06-01

134

Resolution in optically addressed spatial light modulators based on dye-doped liquid crystals.  

PubMed

Dye-doped nematic liquid crystals (LCs) are studied as materials for single-layer optically addressed spatial light modulators. The dopant is 2,5-azo-substituted anthraquinone (ASAQ) dye. The resolution in the ASAQ-doped LC systems does not depend on the device thickness (in the 5-125 microm range). The efficiency increases with the increase of the thickness and begins to saturate in devices thicker than 40 microm. The limiting resolution in the thick devices is 400 line pairs per millimeter. The limitations of performance (efficiency and resolution) in the studied systems are discussed. PMID:17119588

Trushkevych, Oksana; Collings, Neil; Crossland, William A; Wilkinson, Timothy D

2006-12-10

135

Thermomechanical effects in uniformly aligned dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

We show theoretically that thermomechanical effects in dye-doped nematic liquid crystals when illuminated by laser beams, can become important and lead to molecular reorientation at intensities substantially lower than that needed for optical Fréedericksz transition. We propose a 1D model that assumes homogenous intensity distribution in the plane of the layer and is capable to describe such a thermally induced threshold lowering. We consider a particular geometry, with a linearly polarized light incident perpendicularly on a layer of homeotropically aligned dye-doped nematics.

Krimer, D. O.; Residori, S.

2007-05-01

136

Resolution in optically addressed spatial light modulators based on dye-doped liquid crystals  

NASA Astrophysics Data System (ADS)

Dye-doped nematic liquid crystals (LCs) are studied as materials for single-layer optically addressed spatial light modulators. The dopant is 2,5-azo-substituted anthraquinone (ASAQ) dye. The resolution in the ASAQ-doped LC systems does not depend on the device thickness (in the 5-125 ?m range). The efficiency increases with the increase of the thickness and begins to saturate in devices thicker than 40 ?m. The limiting resolution in the thick devices is 400 line pairs per millimeter. The limitations of performance (efficiency and resolution) in the studied systems are discussed.

Trushkevych, Oksana; Collings, Neil; Crossland, William A.; Wilkinson, Timothy D.

2006-12-01

137

Thermomechanical effects in uniformly aligned dye-doped nematic liquid crystals.  

PubMed

We show theoretically that thermomechanical effects in dye-doped nematic liquid crystals when illuminated by laser beams, can become important and lead to molecular reorientation at intensities substantially lower than that needed for optical Fréedericksz transition. We propose a 1D model that assumes homogenous intensity distribution in the plane of the layer and is capable to describe such a thermally induced threshold lowering. We consider a particular geometry, with a linearly polarized light incident perpendicularly on a layer of homeotropically aligned dye-doped nematics. PMID:17522757

Krimer, D O; Residori, S

2007-05-01

138

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

SciTech Connect

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.

Sinha, Nidhi [Department of Electronics, SGTB Khalsa College, University of Delhi, Delhi-110007 (India); Goel, Neeti; Singh, B.K.; Gupta, M.K. [Crystal Lab, Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India); Kumar, Binay, E-mail: bkumar@physics.du.ac.in [Crystal Lab, Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)

2012-06-15

139

Properties of novel yellow anthraquinone dichroic dyes with naphthylthio groups for guest-host liquid crystal displays  

NASA Astrophysics Data System (ADS)

Yellow anthraquinone dichroic dyes, 1,5-bis(2-naphthylthio) anthraquinone 2 and 1-[4-( t-butyl)phenylthio]-5-(2-naphthylthio) anthraquinone 4 were synthesized. Dye 4 in addition to being highly soluble in fluorinated liquid crystals and having a very small temperature dependence of solubility, has a larger dichroic ratio ( DR = 11.7), contrast ratio ( CR = 10.7) and molar absorption coefficient ( ? = 12,000) than a previous yellow anthraquinone dye 3 with two phenylthio groups owing to the effect of having a naphthylthio substituted at one of the substituents. In comparison with molecular structures of dyes 3 and 4, annulation of an arylthio group from a phenylthio group to a naphthylthio group is effective for improving these properties of dichroic dyes. Dye 4 fulfills the desired properties for guest-host liquid crystal displays to realize high performances.

Iwanaga, Hiroki; Naito, Katsuyuki; Aiga, Fumihiko

2010-06-01

140

Manipulation of small objects in liquid crystals by dynamical disorganizing effect of push-pull-azobenzene-dye  

NASA Astrophysics Data System (ADS)

A few research group reports formation of ordered structures of colloidal particles due to topological defects in a nematic liquid crystal. In this paper, we describe the photochemical phase transition of a nematic liquid crystal by the photoisomerization of azobenzene dyes, focusing especially on the dynamical effect of the trans-cis-trans photoisomerization cycle of a push-pull azobenzene dye. Then, we discuss the effects of light irradiation on the motion of small objects dispersed in the nematic and smectic liquid crystals contatining a push-pull azobenzene dye, and successfully manipulate those objects by pushing, trapping and dragging them.

Kuwahara, Yutaka; Oda, Takahiro; Izumi, Ryo; Ogata, Tomonari; Kim, Sun-Nam; Kurihara, Seiji

2014-02-01

141

Relation between phase diagram, crystallization, and optical properties of cyanine dye/stearic acid mixed monolayers  

SciTech Connect

The phase behavior of cyanine dye monolayers mixed with stearic acid as cosurfactant was investigated at various mole fractions, x, by recording pressure-area isotherms at the water-air interface. The resulting pressure-composition phase diagram shows a eutectic behavior with mixed crystal formation. In the miscibility gap ranging from x {approx} 0.3 to x {approx} 0.95 above the eutectic pressure {pi}{sub e} = 40 mN{center dot}m{sup {minus}1} the two coexisting crystal modifications are characterized (among other techniques) by fluorescence microscopy and, after transfer to a suitable substrate, by electron diffraction. The dye-rich (x = 0.95) crystals show all the characteristic features of the brick-stone arrangement proposed for the molecular packing of the dye chromophores in J aggregates. The x = 0.3 phase boundary with a distinctly different crystal habit is stabilized by the areal match between the chromophore headgroups and the densely packed hydrocarbon chains. These thermodynamic and structural data are discussed in relation to the optical properties of the J-band aggregates.

Duschl, C.; Kemper, D.; Frey, W.; Meller, P.; Ringsdorf, H.; Knoll, W. (Max-Planck-Institut fuer Polymerforschung, Mainz (Germany, F.R.) Johannes-Gutenberg-Universitaet, Mainz (Germany, F.R.) Technische Universitaet Muenchen, Garching (Germany, F.R.))

1989-06-01

142

Influence of protein composition on total urinary protein determined by pyrocatechol-violet (UPRO vitros) and pyrogallol red dye binding methods.  

PubMed

Influence of protein composition on total urinary protein assays was evaluated for pyrogallol red-molybdate both with and without sodium dodecyl sulfate (SDS) and pyrocatechol violet-molybdate complex (UPRO) techniques. Using mixtures of albumin and gamma-globulins (n = 8; albumin/globulin ratio, 0 to 10), mean recoveries were 79, 77, and 81% for pyrogallol red, pyrogallol red-SDS, and UPRO, respectively. Using diluted myeloma sera (n = 26; A/G ratio, 0.39 to 2.35), mean recovery by the UPRO method was 115% (vs. 63% for pyrogallol red and 83% pyrogallol red-SDS). Results positively correlated with A/G ratio for UPRO (r = 0.69; P < 0.001), pyrogallol red (r = 0.48; P < 0.05), but not pyrogallol red-SDS (r = 0.191; NS). The difference between UPRO and pyrogallol red assays correlated with the A/G ratio (r = 0.82; P < 0.001). In light chain proteinuria (n = 10), no significant difference (< 15%) was observed between techniques, whereas in glomerular selective proteinuria (n = 10), values were significantly higher with the UPRO assay (2.20 +/- 1.61 vs. 1.43 +/- 1.10 g/L; P < 0.02). Our results support the idea that screening for renal diseases can be performed with UPRO or pyrogallol red assays. However, since A/G ratios may vary with renal disease evolution, follow-up of patients with positive proteinuria should be performed using the same assay, preferably the pyrogallol red-SDS. PMID:11170233

Lefèvre, G; Bloch, S; Le Bricon, T; Billier, S; Arien, S; Capeau, J

2001-01-01

143

Effect of pump efficiency on lasing in dye-doped chiral nematic liquid crystals  

NASA Astrophysics Data System (ADS)

The purpose of this study was to investigate the effect of varying the pump efficiency of dye-doped chiral nematic liquid crystal lasers, through the dependence on absorption efficiency. Two dyes from the rhodamine subset of the xanthene family (rhodamine B and rhodamine 6G) with similar chemical properties but different absorption and emission spectra have been compared for a fixed pumping wavelength (532nm). Each dye was dissolved in E49 (a commercial nematic mixture from Merck NB-C) and the resulting mixtures characterised in terms of their absorption and laser induced fluorescence spectra. A high twisting power chiral dopant (BDH1281, also from Merck NB-C) was used to induce 1-D photonic band gaps with the high and low energy edges corresponding to the fluorescence maximum for each dye. Laser action was induced in the resulting four mixtures and typical laser parameters such as slope efficiency and threshold energy were examined for each one. The results indicate that the mixtures doped with rhodamine 6G had an absolute absorption ~ 57% greater than those doped with rhodamine B. Rhodamine 6G-doped mixtures therefore had the highest pump efficiency and lased more than 6 times more efficiently then those doped with rhodamine B. We believe that the performance of rhodamine 6G is also influenced by its greater degree of alignment with the liquid crystal host and a possible input energy dependence of the quantum efficiency of the dyes (indicated by the fluorescence characteristics of the achiral dye-doped mixtures). Further experimentation is needed to determine exactly which parameters are responsible for the superior performance of rhodamine 6G in chiral nematic lasers.

Gillespie, Carrie; Morris, Stephen M.; Coles, Harry J.

2005-04-01

144

Lasing characteristics of a dye-doped nematic liquid crystal layer sandwiched by two polymeric cholesteric liquid crystals  

NASA Astrophysics Data System (ADS)

We have studied the lasing characteristics from a dye-doped nematic layer sandwiched by two polymeric cholesteric liquid crystal (PCLC) films as photonic band gap materials. The nematic layer possessing birefringence brings about the following remarkable optical characteristics; (1) reflectance in the photonic band gap (PBG) region exceeds 50% due to the retardation effect, being unpredictable from a single CLC film, (2) efficient lasing occurs either at the notch of PBG or at the photonic band edge, (3) the lasing emisions contain both right- and left-circular polarizations, and (4) tunable lasing can be achieved by the reorientation of nematic liquid crystal molecule under the application of an electric field.

Song, Myoung Hoon; Park, Byoungchoo; Shin, Ki-Chul; Ohta, Takashi; Tsunoda, Yuko; Hoshi, Hajime; Takanishi, Yoichi; Ishikawa, Ken; Watanabe, Junji; Nishimura, Suzushi; Toyooka, Takehiro; Zhu, Zhengguo; Swager, Timothy M.; Takezoe, Hideo

2004-10-01

145

Light shutter using dichroic-dye-doped long-pitch cholesteric liquid crystals.  

PubMed

We propose a light shutter device using dichroic-dye-doped liquid crystals (LCs) whose Bragg reflection wavelength is set to be infrared by controlling the pitch of cholesteric liquid crystals (ChLCs). A dye-doped long-pitch ChLC cell is switchable between the dark planar state and the transparent homeotropic state. It has the advantages of high transmittance, low operation voltage, and an easy fabrication process relative to previous LC light shutter devices. The proposed light shutter device is expected to achieve high visibility for transparent organic light-emitting diode displays and emerging smart windows, which can be used in airplanes, cars, and other similar applications. PMID:24514486

Yu, Byeong-Hun; Huh, Jae-Won; Kim, Ki-Han; Yoon, Tae-Hoon

2013-12-01

146

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

PubMed Central

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.

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

2012-01-01

147

Transient and steady state photorefractive responses in dye-doped nematic liquid crystal cells  

NASA Astrophysics Data System (ADS)

The photorefractive response of several dye-doped nematic liquid crystal samples is studied experimentally. Particular attention is given to the observation and modeling of the multiexponential dynamics of the photorefractive grating, and of the photocurrent. Both involve at least two different mechanisms with largely different time constants. These phenomena occur on time scales on the order of seconds, for applied voltages about 1 V, and light intensities as low as milliwatts/cm2.

Klysubun, Prapong; Indebetouw, Guy

2002-02-01

148

Two-wave mixing in chiral dye-doped nematic liquid crystals.  

PubMed

Two-wave mixing in nematic liquid crystals doped with dyes and chiral agents is studied. The photo-induced spatial modulation of the chiral structure, together with the diffusion anisotropy of the mixture, determine a relatively fast response time, a spatial resolution of 1 ?m, and a maximum gain for circularly polarized interacting beams. The gain is insensitive to changes in linear polarization, while it varies with the grating period and with the pump-to-signal intensity ratio. PMID:22344164

Wei, D; Iljin, A; Cai, Z; Residori, S; Bortolozzo, U

2012-02-15

149

Highly efficient and polarization-independent Fresnel lens based on dye-doped liquid crystal.  

PubMed

We demonstrated a highly efficient, polarization-independent and electrically tunable Fresnel lens based on dye-doped liquid crystal using double-side photoalignment technique. The maximum diffraction efficiency reaches 37%, which approaches the theoretical limit ~41%. Such a lens functions as a half-wave plate, and this feature could be well preserved under the applied voltage. In addition, the device is simple to fabricate, and has fast switching responses between focusing and defocusing state. PMID:19532525

Lin, Liang-Chen; Jau, Hung-Chang; Lin, Tsung-Hsien; Fuh, Andy Y

2007-03-19

150

Effects of dichroic dye on the dielectric properties of ferroelectric liquid crystal mixture  

Microsoft Academic Search

The dielectric spectroscopy of the ferroelectric liquid crystal mixture FLC-6980 doped with a low concentration (~2% wt\\/wt) of anthraquinone dye has been studied. The complex permittivity has been measured in the frequency range 100 Hz to 1 MHz in SmC* and SmA phases. Dielectric increments and the relaxation frequencies at various temperatures have been evaluated. Our results indicate that the

K. K. Raina; Arvind K. Gathania; Buta Singh

1999-01-01

151

Rosanilins: indicator dyes for chloramphenicol-resistant enterobacteria containing chloramphenicol acetyltransferase.  

PubMed

Rosanilin dyes such as crystal violet and basic fuchsin have been used as indicator dyes in solid growth medium for chloramphenicol-resistant enterobacterial colonies containing the enterobacterial resistance enzyme chloramphenicol acetyltransferase (CAT). On certain media containing rosanilins, cells containing CAT formed darker colonies than cells not containing CAT. Contrast was affected by the types and concentrations of complex nutrients, sugars salts, and rosanilin dyes present. When crystal violet was used as the indicator dye, contrast could not be obtained for strains whose growth was partially inhibited by crystal violet. Contrast could not be obtained between yeast colonies with and without the enterobacterial resistance enzyme, between Bacillus subtilis colonies with and without the staphylococcal resistance enzyme, or between enterobacterial colonies with and without the staphylococcal resistance enzyme. The darker coloration of enterobacterial colonies with the enterobacterial enzyme was due to the binding of dye to enzyme. Rosanilin dues have been used to score resistance phenotypes by colony color, to detect chloramphenicol-sensitive sectors in chloramphenicol-resistant colonies, and to screen for occasional chloramphenicol-sensitive cells in a resistant population during cloning by insertional inactivation of the chloramphenicol resistance gene. PMID:7042691

Proctor, G N; Rownd, R H

1982-06-01

152

Nonlinear optical organic co-crystals of merocyanine dyes and phenolic derivatives with short hydrogen bonds  

NASA Astrophysics Data System (ADS)

We investigated the co-crystallization of merocyanine dyes M ( M: R-N +C 5H 4-CH?CH-C 6H 4O -, M1: R=CH 3, M2: R=HO-CH 2-CH 2-) with phenolic and aniline derivatives and show that the short or very short hydrogen bond between the two phenolic oxygen atoms which lead to a self-assembly of the M dyes and phenol derivatives is the key steering force for the co-crystallization process. The co-crystal formation was studied by melting point determination, by second-harmonic generation using the Kurtz and Perry powder test, and X-ray structural analysis. We present detailed results on the growth, polymorphism, and nonlinear optical properties of co-crystals of derivatives of M1 ( M2) and m-nitrophenol (mNP) and co-crystals of M2 and methyl 2,4-dihydroxybenzoate (MDB). Three phases of the co-crystal M2·mNP and three phases of the co-crystal M2·MDB were found. Both M2·MDB(I) and (II) have the same crystal structure (space group symmetry Cc determined by X-ray diffraction), but show different linear and nonlinear optical properties. This unusual property in the co-crystals of M2·MDB(I) and (II) may be caused by a different proton location of the short hydrogen bond (O-H-O) in the aggregation between M2 and MDB which could not be resolved by X-ray diffraction.

Bosshard, Christian; Pan, Feng; Wong, Man Shing; Manetta, Sabine; Spreiter, Rolf; Cai, Chengzhi; Günter, Peter; Gramlich, Volker

1999-07-01

153

Polarization-controlled contrasted images using dye-doped nematic liquid crystals.  

PubMed

We explore the polarization dependence of the nonlinear response of a planar nematic liquid crystal cell doped with 1% wt of methyl red dye. The results obtained show that the refractive index change can be switched from a positive value to a negative one as the polarization of the beam changes from parallel to perpendicular with respect to the rubbing direction. This property is exploited in a phase contrast system, where a dynamic phase filter is photoinduced in a liquid crystal cell placed in the system's Fourier plane. Real-time contrast inversion in the resulting images is demonstrated. PMID:19259179

Porras Aguilar, R; Ramirez-San-Juan, J C; Baldovino-Pantaleon, O; May-Arrioja, D; Arroyo Carrasco, M L; Iturbe-Castillo, M D; Sánchez-de-la-Llave, D; Ramos-Garcia, R

2009-03-01

154

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

SciTech Connect

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.

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

155

Emission property of inverse opal photonic crystal TiO2 infiltrated by laser dye  

NASA Astrophysics Data System (ADS)

Photonic crystal has received much attention due to their unique structure and optical property. Photonic crystal which has photonic bandgap can be used to manipulate propagation of light and can be apply in designing integrated optical devices to realize all-optical circuits. Three dimensional photonic crystals which have complete photonic bandgap give more potential in application since they can manipulate propagation of light in all direction. Modified opal photonic crystal by infiltrating matrix material into voids between particles produce inverse opal photonic crystal which has complete photonic bandgap. In this experiment, opal photonic crystal formed from particles polystyrene was used as template material to produce inverse opal photonic crystal. Material dielectric TiO2 which has refractive index about 2,5-2,8 was used as matrix material to fill voids between particles. Simple method that was used to infiltrate precursor TiO2 dielectric is dipping method. Calcination as the final process was done at 550°C to remove all template material to form an air hole structure called inverse opal photonic crystal. To investigate inverse opal photonic crystal TiO2as an optical devices, DCMlaser dye wasinfiltrated into inverse opal TiO2. Based on emission measurement, there is a sharp peak at 808 nm that is identified as amplified spontaneous emission (ASE).

Safriani, Lusi; Wahid, Abdul; Hidayat, Sahrul

2013-09-01

156

All-optical modulation in dye-doped nematic liquid crystal photonic bandgap fibers  

NASA Astrophysics Data System (ADS)

Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate an all-optical modulator, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. We demonstrate a modulation frequency of 2kHz for a moderate pump power of 2-3mW and describe two pump pulse regimes in which there is an order of magnitude difference between the decay times.

Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper; Bjarklev, Anders; Hermann, David Sparre; Anawati, Anawati; Broeng, Jes; Li, Jun; Wu, Shin-Tson

2004-11-01

157

All-optical modulation in dye-doped nematic liquid crystal photonic bandgap fibers.  

PubMed

Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate an all-optical modulator, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. We demonstrate a modulation frequency of 2kHz for a moderate pump power of 2-3mW and describe two pump pulse regimes in which there is an order of magnitude difference between the decay times. PMID:19488225

Alkeskjold, Thomas; Lægsgaard, Jesper; Bjarklev, Anders; Hermann, David; Anawati, Anawati; Broeng, Jes; Li, Jun; Wu, Shin-Tson

2004-11-29

158

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)

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.

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

2012-10-01

159

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

PubMed

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. PMID:23034818

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

2012-11-01

160

Polymer photonic crystal dye lasers as label free evanescent cell sensors  

NASA Astrophysics Data System (ADS)

Dye doped polymer photonic crystal band edge lasers are applied for evanescent wave sensing of cells. The lasers are rectangular shaped slab waveguides of dye doped polymer on a glass substrate, where a photonic crystal is formed by 100 nm deep air-holes in the surface of the 375 nm high waveguides. The lasers are fabricated by combined nanoimprint and photolithography (CNP) in Ormocore hybrid polymer doped with the laser dye Pyrromethene 597. The lasers emit in the chip plane at a wavelength around 595 nm when pumped with 5 ns pulses from a compact frequency doubled Nd:YAG laser. We investigate the sensitivity of photonic crystal band-edge lasers to partial coverage with HeLa cells. The lasers are chemically activated with a flexible UV activated anthraquinone based linker molecule, which enables selective binding of cells and molecules. When measuring in Phosphate Buffered Saline (PBS), which has a refractive index close to that of the cells, the emission wavelength depends linearly on the cell density on the sensor surface. Our results demonstrate that nanostructured hybrid polymer lasers, which are cheap to fabricate and very simple to operate, can be selectively chemically activated with UV sensitive photolinkers for further bioanalytical applications. This opens the possibility to functionalize arrays of optofluidic laser sensors with different bio-recognition molecules for multiplexed sensing. The linear relationship between cell coverage and wavelength indicates that the slight refractive index perturbation from the partial coverage of the sensor influences the entire optical mode, rather than breaking down the photonic crystal feedback.

Christiansen, Mads B.; Lopacinska, Joanna M.; Jakobsen, Mogens H.; Mortensen, Niels A.; Dufva, Martin; Kristensen, Anders

2009-08-01

161

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

NASA Astrophysics Data System (ADS)

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.

Campbell, Jeremy; Rorrer, Greg

2013-10-01

162

Molecular reorientation-based grating diffraction in dye-doped nematic liquid crystals with red pumping source  

NASA Astrophysics Data System (ADS)

We report the results of a grating diffraction experiment in which a blue anthraquinone dye, Disperse blue 14, is doped to nematic liquid crystal host and the sample is employed as a nonlinear media. The change of refractive index, caused by the photoinduced molecular reorientation, brings about the promising grating diffraction capability of a novel liquid crystal system. This system contains an anthraquinone dye in the absorbance band of red He-Ne laser, which is used as a pumping source. Accessible diffraction efficiency is 20% under optimum circumstances and analyzed results are in consistency with the expectations reinforced by the literature information of the other resembling liquid crystal systems.

San, S. E.; Köysal, O.; Ecevit, F. N.

2002-11-01

163

Holographic grating formation mechanism in dye-doped nematic liquid crystal thin layer under dc electric field  

NASA Astrophysics Data System (ADS)

Mechanism of holographic dynamic grating recording in a thin cell with dye doped nematic liquid crystal under laser light has been proposed. Nematic liquid crystal with dye is sandwiched between two coating glass plates covered by ITO conductive and polyimide orientation layers. In this experiment, two interfering laser beams induced spatial modulation of refraction index and form interference pattern in the liquid crystal cell. The recording mechanism is linked with DC electric field driven reorientation of nematic director and induces the bulk photoconductivity of the system.

Parka, Janusz; Januszko, A.; Miniewicz, Andrzej; Zmija, Jozef

2000-05-01

164

Molecular organization and aggregation in Langmuir and Langmuir-Blodgett films of azo dye/liquid crystal mixtures  

NASA Astrophysics Data System (ADS)

A study of azo dye/liquid crystal mixtures in monolayers formed at air-water (Langmuir films) and air-solid substrate (Langmuir-Blodgett films) interfaces was performed. Three azo dyes with various molecular structure and two liquid crystal materials: 4-octyl-4'-cyanobiphenyl (8CB) and trans-4-octyl(4'-cyanophenyl)-cyclohexane (8PCH) were used. The morphology of Langmuir films was monitored by means of a Brewster angle microscope (BAM). Moreover, a surface pressure and electronic absorption spectra of the monolayer spread on the water surface of dye/liquid crystal mixtures as a function of a mean molecular area were simultaneously recorded. In addition, the absorption for Langmuir-Blodgett films deposited on quartz plates was measured. Information about intermolecular interactions in the mixtures of the nonamphiphilic dye and the liquid crystal with polar terminal group was obtained. Conclusions about the formation of self-aggregates between dye molecules have been drawn. The influence of the dye molecular structure and its concentration on aggregates’ geometry was found.

Inglot, K.; Marty?ski, T.; Bauman, D.

2009-06-01

165

Characterization of N3 dye adsorption on TiO2 using quartz-crystal microbalance with dissipation monitoring  

NASA Astrophysics Data System (ADS)

Understanding the kinetics of dye adsorption on semiconductors is crucial for designing dye-sensitized solar cells (DSSCs) with enhanced efficiency. Harms et al. recently applied the Quartz-Crystal Microbalance with Dissipation Monitoring (QCM-D) to study in situ dye adsorption on flat TiO2 surfaces. QCM-D measures adsorption in real time and therefore allows one to determine the kinetics of the process. In this work, we characterize the adsorption of N3, a commercial RuBipy dye, using the native oxide layer of a titanium sensor to simulate the TiO2 substrate of a DSSC. We report equilibrium constants that are in agreement with previous absorbance studies of N3 adsorption, and therefore demonstrate the native oxide layer of a titanium sensor as a valid and readily available planar TiO2 morphology to study dye adsorption.

Wayment-Steele, Hannah K.; Johnson, Lewis E.; Dixon, Matthew C.; Johal, Malkiat S.

2013-09-01

166

Polarization tunable circular Dammann grating generated from azo-dye doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

A polarization tunable circular Dammann grating (CDG) was generated from an azo-dye (Methyl Red from Aldrich) doped liquid crystal (LC, E7 from Merck) cell. A simple multi-exposure photo-aligned process, based on cell assembled with non-rubbing glass substrates, was used to fabricate the binary phase liquid crystal CDG zone plane consisted of even zone with homogenous LC structure and odd zone with TN LC structure. Different twist angle of fabricated TN structure for odd zone can be obtained by adjusting photo exposure intensity or time. CDG with equal-intensity rings was produced through a Fourier-transform and then captured by a charge-coupled-device in our experiment. The maximum 0th and 1st diffraction orders of obtained CDG can be separated achieved by rotating the analyzer's polarization direction. If the chosen analyzer's direction leads to a zero phase difference of output light from even and odd zones, the maximum 0th diffraction order will be achieved, in contrast, if the chosen analyzer's direction leads to a ? phase difference of output light from even and odd zones, the maximum 1st diffraction order will be produced. The TN structure of azo-dye doped liquid crystal cell fabricated by photo alignment technique provides a new method to generate CDG with polarization-dependent property. A broad wavelength band of lasers used to generate CDG, if far away from MR azo-dye absorption peak, expands the device's application range and shows a great advantage comparing to previously reported CDG fabricated by fixed materials, where only one fixed working wavelength is allowed.

Luo, D.; Dai, H. T.; Sun, X. W.

2011-02-01

167

Polarization and polarization control of random lasers from dye-doped nematic liquid crystals.  

PubMed

A polarimetric study of random laser (RL) emitted from dye-doped nematic liquid crystals (NLCs) is presented. We observed linearly polarized light, the orientation of which is in proximity to the bisection between the polarization direction at the maximal scattering in NLCs and the nematic director. Any arbitrary linear polarization of RLs can be obtained by rotating the NLC sample. The efficiency and output uniformity over the complete direction angle of 2? can be optimized by choosing a proper pump polarization. PMID:23632550

Yao, Fengfeng; Zhou, Wenlong; Bian, Huanting; Zhang, Yu; Pei, Yanbo; Sun, Xiudong; Lv, Zhiwei

2013-05-01

168

Anomalous intensity dependence of optical reorientation in azo-dye-doped nematic liquid crystals.  

PubMed

The intensity dependence of optical nonlinearity in a nematic liquid crystal doped with an azo-dye is investigated. The reorientational part of the nonlinearity changes from self-defocusing to self-focusing character while the intensity passes through the saturation value of trans-cis photoisomerization. This observation, in accordance with previous models, indicates that the optical torque generated by the trans-isomers is of opposite sign than the torque generated by the cis-isomers. At very low intensities a further reorientational nonlinearity was found, which is attributed to light-induced orientational redistribution of adsorbed molecules at the surface. PMID:15244837

Becchi, M; Janossy, I; Shankar Rao, D S; Statman, D

2004-05-01

169

Surface-stabilized holography in an azo-dye-doped liquid crystal.  

PubMed

Holograms are recorded by a 514-nm laser polarized parallel to the molecular director in an azo-dye-doped nematic liquid crystal. For some surface treatments, the recorded holograms persist in the dark. For glass surfaces, exposure to light polarized normal to the molecular director erases the hologram. The hologram also vanishes when the sample is heated across the nematic to isotropic phase transition but reappears when the sample is cooled back to the nematic phase. The dynamics and strength of this effect depend strongly on the surface treatment of the sample cell. PMID:19798143

Chen, A G; Brady, D J

1992-09-01

170

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

SciTech Connect

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.

Lin, T.-H.; Fuh, Andy Y.-G. [Institute of Electro-optical Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Department of Physics, and Institute of Electro-optical Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China)

2005-07-04

171

Light-induced softening of azobenzene dye-doped polymer films probed with quartz crystal resonators  

NASA Astrophysics Data System (ADS)

Employing quartz crystal resonators, we have measured the elastic compliance of thin polymers films doped with an azobenzene dye. From a comparison of the shifts of resonance frequency on different acoustic overtones of the resonator, the films' elastic compliance was derived. Upon irradiation with ultraviolett light at low intensity, the compliance decreases by a few percent. Irradiation with visible light at high intensity, on the contrary, softens the material. We assume that, when irradiated with high-power visible light, the azobenzene molecules undergo rapid cycling through the trans- and cis-states, thereby softening the polymer matrix.

Srikhirin, Toemsak; Laschitsch, Alexander; Neher, Dieter; Johannsmann, Diethelm

2000-08-01

172

A Method for Improving Contrast Ratio of Polymer Dispersed Liquid Crystal Film Using the Oriented Azo-Dye Molecules in Polymer Matrix  

Microsoft Academic Search

An improvement in the contrast ratio (CR) of transmittance characteristic of polymer dispersed liquid crystal (PDLC) was achieved by doping the polymer matrix with azo-dye and then orienting the dye molecules with the photo pumping technique. The contrast ratio was measured by the light scattering technique. We investigated the optimum conditions for the scattering characteristics of the dye-doped PDLC films

Seung-Hee Lee; Tong-Kun Lim; Sung-Tae Shin; Kwan-Sun Park

2002-01-01

173

All-optical switching of continuous wave, microsecond lasers with a dye-doped nematic liquid crystal  

NASA Astrophysics Data System (ADS)

The authors present a theoretical analysis and experimental demonstration of optically self-activated polarization switching process in a 90° twist alignment dye-doped nematic liquid crystal. The underlying mechanisms are laser induced dye-assisted director axis reorientation and order parameter modifications. Experimental observations are in good agreement with the theoretical expectations derived from a modified Jones matrix calculation, and demonstrate the feasibility of designing efficient low threshold polarization and fast switching and optical limiting devices for cw and microsecond lasers.

Khoo, I. C.; Park, Jae-Hong; Liou, Justin

2007-04-01

174

How doping a cholesteric liquid crystal with polymeric dye improves an order parameter and makes possible low threshold lasing  

Microsoft Academic Search

Lasing conditions in a dye-doped cholesteric liquid crystal (ChLC) have been studied in view of optical modes for the light propagating in ChLCs using a polymeric dye with the transition dipole moment parallel to the local director of the ChLC host. We found that lasing always occurs at the lower-energy edge of the photonic gap. This is because that the

Fumito Araoka; Ki-Chul Shin; Yoichi Takanishi; Ken Ishikawa; Hideo Takezoe; Zhengguo Zhu; Timothy M. Swager

2003-01-01

175

Effect of dichroic dye on phase separation kinetics and electro-optical characteristics of polymer dispersed liquid crystals  

NASA Astrophysics Data System (ADS)

Dichroic polymer dispersed liquid crystal (PDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and dichroic azo dye by polymerization induced phase separation (PIPS) method. Dynamics of PIPS and morphology development in the mixtures containing dye have been investigated by means of UV-VIS spectroscopy and optical microscopy. The phase separation and segregation of LC droplets was found to be dependent on the amount of dye used. LC droplets predominantly exhibited bipolar configuration that changed to maltese type crosses under the influence of an applied electric field. The extent of interaction and anchoring energy between the LC and polymer were examined by measuring contact angle in consequence of dye addition. Due to less interfacial interaction, PDLC with low dye content (?0.06 wt%) gave a good contrast ratio, relatively low threshold voltage and a value of high transmittance in the ON-state. UV-VIS spectroscopy results show that the molecular orientation of dye in LC droplets can be controlled with an applied field to induce nonlinearity in these materials. In particular, the dye concentration can be optimized to obtain promising electronic materials with minimum threshold and high contrast for display applications.

Deshmukh, R. R.; Malik, M. K.

2013-02-01

176

All-optical switchable holographic Fresnel lens based on azo-dye-doped polymer-dispersed liquid crystals.  

PubMed

Fabrication of an all-optical switchable holographic liquid crystal (LC) Fresnel lens based on azo-dye-doped polymer-dispersed LCs is reported using a Michelson interferometer. It is found that, upon circularly polarized photoirradiation, the diffraction efficiency of the fabricated Fresnel lens was increased significantly in a reversible manner. We believe this is due to the anisotropy induced by reorientation of the LC molecules coupled with azo-dye molecule orientation due to trans-cis-trans photoisomerization, which modulates the refractive index of the LC-rich regions. We also studied the effect of azo dye on the polarization dependency of the fabricated lens. PMID:21833102

Jashnsaz, Hossein; Nataj, Nahid Hosain; Mohajerani, Ezeddin; Khabbazi, Amir

2011-08-01

177

Immunomagnetic separation of Erwinia carotovora subsp. atroseptica from potato peel extracts to improve detection sensitivity on a crystal violet pectate medium or by PCR.  

PubMed

Immunomagnetic separation (IMS) procedures for the selective separation of Erwinia carotovora subsp. atroseptica from potato peel extract were optimized for the recovery of target and removal of non-target bacteria. A streptomycin-resistant strain of Erw. carotovora subsp. atroseptica was used in combination with a crystal violet pectate (CVP) medium supplemented with 100 micrograms ml-1 of streptomycin to determine the recovery level of the target bacterium. Recovery obtained with a polyclonal antiserum against Erw. carotovora subsp. atroseptica at a concentration of 6 micrograms IgG ml-1 was greater than that obtained with two monoclonal antibodies against lipopolysaccharides of Erw. carotovora subsp. atroseptica at a concentration of 10 micrograms IgG ml-1. A linear relationship was found between particle concentration ranging from 12 to 200 micrograms ml-1 and recovery level. When the Advanced Magnetics (AM) protein A and anti-rabbit IgG particles in the AM separation system and the Dynal anti-rabbit IgG particles in the Dynal separation system were examined, the highest recovery level per microgram of particles (66%) was obtained with the Advanced Magnetics protein A particles, followed by AM anti-rabbit particles (37%). Without IMS, detection of Erw. carotovora subsp. atroseptica in tuber peel extracts on a CVP-medium without streptomycin was impossible when the ratio of Erw. carotovora subsp. carotovora to Erw. carotovora subsp. atroseptica was greater than 100 or when large numbers of other saprophytic bacteria were present, because of overcrowding. IMS, using the AM anti-rabbit IgG particles, ensured that Erw. carotovora subsp. atroseptica could be enumerated in tuber peel extract consistently, to a detection level of 100 cells ml-1. Similarly, the IMS procedure lowered the detection level of Erw. carotovora subsp. atroseptica in a twofold diluted peel extract by PCR to ca 2.0 x 10(3) cells ml-1 or 50 cells per reaction tube. In contrast, positive results in PCR without IMS were obtained only when the peel extract was diluted 100 times and when the concentration of Erw. carotovora subsp. atroseptica was at least 10(5) cell ml-1. PMID:9072520

van der Wolf, J M; Hyman, L J; Jones, D A; Grevesse, C; van Beckhoven, J R; van Vuurde, J W; Pérombelon, M C

1996-05-01

178

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

SciTech Connect

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)

Alaverdyan, R B; Gevorgyan, A A; Chilingaryan, A D; Chilingaryan, Yu S [Department of Physics, Yerevan State University, Yerevan (Armenia)

2008-05-31

179

Dye-doped liquid crystal composite for real-time holography  

NASA Astrophysics Data System (ADS)

In this paper we report the results of dynamic phase grating formation in an anthraquinone derivative dichroic dye-doped nematic liquid crystal in which an external DC electric field was used to change the planar alignment of liquid crystal molecules into a near homeotropic one. This field was also needed to produce an efficient grating via photoconductivity-induced molecular reorientation in a degenerate two-wave mixing experiment with He - Ne (632.8 nm) laser light serving as a low power excitation source. The characteristic of the measured effect shows that the mechanism of grating formation is evidently a non-photorefractive one. A diffraction efficiency of up to 20% has been measured in the system. Fast hologram recording and erasing times (1 ms) make this system attractive for image processing applications.

Bartkiewicz, S.; Januszko, A.; Miniewicz, A.; Parka, J.

1996-11-01

180

Mode competition of two bandedge lasing from dye doped cholesteric liquid crystal laser.  

PubMed

Mode competition of two-lasing modes at the photonic bandedge from dye-doped cholesteric liquid crystal lasing was studied by the alternation of temperatures. The increase or decrease of the wavelengths from photonic bandedges versus the alternation of temperature is attributed to the variation of helical twist power (HTP) and thus it shows the completely different result by choosing two of different nematic liquid crystals (MDA-981602 and MDA-3970). At certain temperature, the intensity contrast and slope efficiency between long and short emission lasing peaks were dominated from the experienced gain or loss of laser for the position of the photonic bandedge. By the linear combination of these two lasing modes with different emission wavelengths and intensity contrast at distinct temperature, the wide tuning of the output colors can be revealed from the CIE chromaticity diagram and thus it has opportunity to be used in the display technology in the near future. PMID:24787875

Lin, Ja-Hon; Chen, Po-Yen; Wu, Jin-Jei

2014-04-21

181

Regenerator dependent photoinduced desorption of a dicarboxylated cyanine dye from the surface of single-crystal rutile.  

PubMed

A photon-initiated desorption of a dicarboxylated thiacarbocyanine dye from a dye-sensitized semiconducting oxide crystal has been observed when hydroquinone is used as a regenerator. No desorption was found under the same conditions when KI was used as the regenerator. Intermittent illumination experiments suggest that the oxidation products of the hydroquinone regenerator compete for dye adsorption sites. By comparing the photocurrent decay at both the dye monomer sensitization maximum and the dimer sensitization maximum, a rearrangement of monomer into dimer was observed. A kinetic model for the photocurrent decay as a function of desorption time was derived, and the desorption rate constants were obtained by fitting the experimental data to the model. PMID:17918975

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

2007-11-01

182

Dosimetry characterization of tetrazolium violet-polyvinylalcohol films  

Microsoft Academic Search

The dosimetry characteristics of the polyvinylalcohol-based tetrazolium violet film has been studied in order to check its suitability for routine dosimetry in radiation processing. Our investigations reveal that this dosimeter film can be used for process control in radiation sterilization, but its application range depends on the concentration of the dye and the solvents used. The effects of irradiation temperature

G. Emi-Reynolds; Andras Kovacs; J. J. Fletcher

2007-01-01

183

A comparative study on growth, structural, optical, thermal and mechanical properties of undoped and dye doped bis glycine cadmium chloride single crystals  

NASA Astrophysics Data System (ADS)

Dye inclusion crystals have attracted researchers in the context of crystal growth for applications in solid state lasers. Attempt to grow tris glycine cadmium chloride (TGCC) crystals yielded bis glycine cadmium chloride crystals. Single crystals of bis glycine cadmium chloride (BGCC) and organic dye, namely xylenol orange tetra sodium salt (XO) doped BGCC crystals, were grown from aqueous solutions by slow evaporation technique from the mixture of an aqueous solution of glycine and cadmium chloride in 3:1 molar ratio at a constant temperature of 35 °C. The grown crystals are up to the dimension of 20×20×5 mm 3. Characterization of the crystals was made using a single crystal X-ray diffractometer for obtaining the structure. The crystal is monoclinic with P2 1/ n space group. High-resolution X-ray diffraction (HRXRD) was used to evaluate crystalline perfection. Perfection of the undoped crystals is higher than those of the dye doped crystals. Thermal stability of the crystals is tested from differential scanning calorimetry. There is only one endothermic peak, indicating melting point. The optical transparency range of the crystals was identified from the UV-vis spectrum. Functional groups present in the crystals were studied by FT-IR spectral analysis. The mechanical strength of the crystals, measured by Vickers microhardness, and it has increased due to the presence of dye in the crystals.

Raju, B.; Saritha, A.; Bhagavannarayana, G.; Hussain, K. A.

2011-06-01

184

Time-domain analysis of optically controllable biphotonic gratings in azo-dye-doped cholesteric liquid crystals.  

PubMed

This study investigated optically controllable biphotonic gratings (BGs) in azo-dye-doped cholesteric liquid crystals. The BGs were formed under the illumination of one green beam with the simultaneous irradiation of an interference field generated by two coherent red beams. This study ascribes the formation of the BGs to the green-beam-induced dye reorientation and elongation of the helical pitch through trans-cis isomerization and red-beam-induced suppression of dye reorientation and elongation of the helical pitch by cis-trans back isomerization. The diffraction characteristics strongly depended on the helical pitch of the cholesteric structure, the polarization state of the probe beam, and the relative intensity of the green and red beams. Application of the finite-difference time-domain method demonstrated that the model of photoinduced distortion of the cholesteric liquid crystal structure satisfactorily explains this dependence. PMID:21445188

Yeh, Hui-Chen

2011-03-14

185

21 CFR 73.3107 - Carbazole violet.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Carbazole violet. 73.3107 Section 73.3107...CERTIFICATION Medical Devices § 73.3107 Carbazole violet. (a) Identity. The color additive is carbazole violet (Pigment Violet 23)...

2009-04-01

186

21 CFR 73.3107 - Carbazole violet.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Carbazole violet. 73.3107 Section 73.3107...CERTIFICATION Medical Devices § 73.3107 Carbazole violet. (a) Identity. The color additive is carbazole violet (Pigment Violet 23)...

2010-04-01

187

Electrically switchable and optically rewritable reflective Fresnel zone plate in dye-doped cholesteric liquid crystals.  

PubMed

This work demonstrates a reflective Fresnel zone plate based on dye-doped cholesteric liquid crystals (DDCLC) using the photo-induced realignment technique. Illumination of a DDCLC film with a laser beam through a Fresnel-zone-plate mask yields a reflective lens with binary-amplitude structures - planar and focal conic textures, which reflect and scatter probed light, respectively. The formed lens persists without any external disturbance, and its focusing efficiency, analyzed using circularly polarized light, is ~ 23.7%, which almost equals the measured diffraction efficiency of the used Fresnel-zone-plate mask (~ 25.6%). The lens is thermally erasable, rewritable and switchable between focusing and defocusing states, upon application of a voltage. PMID:19550680

Cheng, Ko-Ting; Liu, Cheng-Kai; Ting, Chi-Lun; Fuh, Andy Y

2007-10-17

188

Nonlinear Optical Propagation in a Dye-Doped Nematic Liquid Crystal Waveguide  

NASA Astrophysics Data System (ADS)

A dye-doped nematic liquid crystal slab waveguide with an infinite homogeneous isotropic cladding is considered. The problem of light propagation in such a system is solved by a set of coupled nonlinear differential equations. This equation set is directly derived from the exact Maxwell's equations for the light and the torque balance equations for the medium response. The optical field amplitudes and the molecular director distributions are computed by means of a numerical technique based on the continuation method. The numerical results give evidence for a threshold effect, OFT-like. Above threshold, degeneration of modes and self-induced spatial splitting of the guided beam occur. Among the possible applications we propose a nonlinear switch for integrated optics.

Abbate, G.; de Stefano, L.

189

Tailoring of random lasing characteristics in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

Amplified spontaneous emission and random lasing are investigated in random systems with dye-doped nematic liquid crystals. And that temporal stability of random lasing is analyzed. The influence of pumping polarization as well as the multiple scattering and reflection between boundaries on the emission behavior and the formation of coherent feedback is investigated in detail. For freely suspended samples, certain emission wavelength can be obtained by changing the pump wavelength. This feature is useful in making wavelength-tunable lasers. Moreover, as the pumping thickness of wedge sample increases, the emission spectrum is red shifted and the average spacing of adjacent spikes decreases. This property can be applied in laser mode selection, i.e., the number of modes within certain wavelength range can be chosen.

Ye, Lihua; Hou, Cong; Lv, Changgui; Zhao, Chong; Yin, Zhile; Cui, Yiping; Lu, Yanqing

2014-04-01

190

Photo-isomerization fronts in dye-doped nematic liquid crystals.  

PubMed

An experimental study of the photo-isomerization dynamics in dye-doped nematic crystals is reported, which shows that, when the sample is illuminated by a Gaussian beam, and for high enough input power, a transition from the nematic to the isotropic phase takes place in the illuminated area. The two phases are spatially connected via a front propagating outward from the center of the beam and following the local intensity profile and thus inducing a photo-controlled optical aperture. The optical intensity and temperature fields on the sample follow the same dynamical profile. The front dynamics is described by a phenomenological bi-stable model with an inhomogeneous control parameter, directly related to the beam intensity profile. PMID:24686624

Odent, V; Clerc, M G; Falcón, C; Bortolozzo, U; Louvergneaux, E; Residori, S

2014-04-01

191

Laser Field Induced Azimuthal Anchoring Gliding in Dye Doped Nematic Liquid Crystals  

NASA Astrophysics Data System (ADS)

We have analyzed the rotating effect of an Ar+ linearly polarized laser beam on a dye-doped nematic liquid crystal (DDNLC) in a pump-probe experiment. An asymmetric capillary cell with two polymer coated glasses was used. An easy axis was induced by rubbing one surface, the other one remained non-oriented. The exciting laser beam entering the orienting surface has the polarization direction perpendicular to the easy axis. The time dependent transmitted intensity of a probe He-Ne laser beam (polarization direction parallel to the easy axis) has been measured. For large enough Ar+ laser power a non-monotonous curve (having one or even two maxima) has been observed. We develop a model which explains our experimental data by taking into account the gliding of the easy axis on the orienting surface. The azimuthal anchoring gliding angle has been estimated.

P?l?rie, Ion; E?eanu, Nicoleta

192

Tailoring of random lasing characteristics in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

Amplified spontaneous emission and random lasing are investigated in random systems with dye-doped nematic liquid crystals. And that temporal stability of random lasing is analyzed. The influence of pumping polarization as well as the multiple scattering and reflection between boundaries on the emission behavior and the formation of coherent feedback is investigated in detail. For freely suspended samples, certain emission wavelength can be obtained by changing the pump wavelength. This feature is useful in making wavelength-tunable lasers. Moreover, as the pumping thickness of wedge sample increases, the emission spectrum is red shifted and the average spacing of adjacent spikes decreases. This property can be applied in laser mode selection, i.e., the number of modes within certain wavelength range can be chosen.

Ye, Lihua; Hou, Cong; Lv, Changgui; Zhao, Chong; Yin, Zhile; Cui, Yiping; Lu, Yanqing

2014-06-01

193

Manipulation and assembly of small objects in liquid crystals by dynamical disorganizing effect of push-pull-azobenzene-dye  

PubMed Central

The phase transition of a nematic liquid crystal containing a push-pull azobenzene dye could be induced efficiently during irradiation with visible light. The dynamical disorganizing effect of the push-pull azobenzene dye on the liquid crystalline order through its trans-cis-trans photoisomerizaion cycle under visible light was contributed to the efficient phase transition. Then, the effects of light irradiation on the motion of small objects dispersed in the liquid crystals containing the push-pull azobenzene were explored, and the manipulation and assembly of those objects were successfully achieved in the nematic phase but also in the smectic phase. The combination of the photo-controlled dynamical change in the liquid crystalline order and the intrinsic self-assembly property of a liquid crystal is promising for use in technologies that require not only the organization of small objects but also the photo-driving of nano- and micro-sized mechanical materials.

Kurihara, Seiji; Ohta, Kazuhiro; Oda, Takahiro; Izumi, Ryo; Kuwahara, Yutaka; Ogata, Tomonari; Kim, Sun-Nam

2013-01-01

194

First Crystal Structure of a Fungal High-redox Potential Dye-decolorizing Peroxidase  

PubMed Central

Dye-decolorizing peroxidases (DyPs) belong to the large group of heme peroxidases. They utilize hydrogen peroxide to catalyze oxidations of various organic compounds. AauDyPI from Auricularia auricula-judae (fungi) was crystallized, and its crystal structure was determined at 2.1 ? resolution. The mostly helical structure also shows a ?-sheet motif typical for DyPs and Cld (chlorite dismutase)-related structures and includes the complete polypeptide chain. At the distal side of the heme molecule, a flexible aspartate residue (Asp-168) plays a key role in catalysis. It guides incoming hydrogen peroxide toward the heme iron and mediates proton rearrangement in the process of Compound I formation. Afterward, its side chain changes its conformation, now pointing toward the protein backbone. We propose an extended functionality of Asp-168, which acts like a gatekeeper by altering the width of the heme cavity access channel. Chemical modifications of potentially redox-active amino acids show that a tyrosine is involved in substrate interaction. Using spin-trapping experiments, a transient radical on the surface-exposed Tyr-337 was identified as the oxidation site for bulky substrates. A possible long-range electron transfer pathway from the surface of the enzyme to the redox cofactor (heme) is discussed.

Strittmatter, Eric; Liers, Christiane; Ullrich, Rene; Wachter, Sabrina; Hofrichter, Martin; Plattner, Dietmar A.; Piontek, Klaus

2013-01-01

195

Heat-driven and electric-field-driven bistable devices using dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

We have demonstrated memory and rewritable bistable devices based on an anchoring transition of a nematic liquid crystal on a perfluoropolymer surface. Spontaneous orientation changes between planar and homeotropic occur on cooling and heating with a large temperature hysteresis. Photo (heat) addressing is possible from homeotropic to planar using dye-doped samples. For a coumarin dye, photoaddressed images are preserved even after heating up the sample to the isotropic temperature, whereas, for a 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye the images can be erased by decreasing the temperature out of the thermal hysteresis. Orientation switching also occurs by applying an electric field with a response time of several milliseconds depending on the field strength.

Kim, Jin Ki; van Le, Khoa; Dhara, Surajit; Araoka, Fumito; Ishikawa, Ken; Takezoe, Hideo

2010-06-01

196

Observation of large anomalous orientational nonlinear response in dye-doped liquid crystals at 1320 nm  

NASA Astrophysics Data System (ADS)

IR z-scan and conoscopic measurements have been performed on dye-doped nematic liquid crystal samples to investigate the influence of the dopant on the orientational nonlinear response of the liquid crystalline material, and the result compared to undyed samples. Both the dye-doped and undyed samples were prepared utilizing a surface treatment which produces homeotropic alignment in the undyed, glass-substrate samples. For samples constructed with non-conducting substrates, the dopant only slightly strengthens the nonlinear response of the host material, and the response in all cases is less than half that observed in samples with ITO- coated substrates. Undyed samples displayed no response at normal incidence for the laser intensities used, regardless of substrate, while doped samples displayed significant self- limiting at all angles of incidence. Increasing the dopant concentration further enhances the observed responses, but the time required to achieve the initial alignment state of the nematic increases more rapidly than the response, and significant delays in response to pulsed inputs are also observed. Laser polarization strongly effects the response characteristics, as expected. Z-scan and conoscopic measurements are used to determine the origin of the unusually large response in the ITO-coated samples Initial efforts with conoscopic techniques have found no evidence of pre-tilt in the director orientation, though more sensitive measurements are in process. The presence of a large nonlinear absorption contribution due to the dopant has been observed, though why only ITO-substrate samples may be affected is still under investigation.

Lopresti, Peter G.; Hemphill, Daniel A.

1997-10-01

197

Study of the degradation of dyes by MnP of Phanerochaete chrysosporium produced in a fixed-bed bioreactor  

Microsoft Academic Search

The production of ligninolytic enzymes by the fungus Phanerochaete chrysosporium in a fixed-bed tubular bioreactor, filled with cubes of nylon sponge, operating in semi-solid-state conditions, was studied. Maximum individual manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of 1293 and 225 U\\/l were detected.The in vitro decolourisation of two structurally different dyes (Poly R-478, crystal violet) by the extracellular liquid

D Moldes; S Rodr??guez Couto; C Cameselle; M. A Sanromán

2003-01-01

198

Inactivation of Foot-and-Mouth Disease Virus by Interaction of Dye and Visible Light  

PubMed Central

The inactivation of foot-and-mouth disease virus was studied by means of the interaction of neutral red, Toluidine Blue, and methylene blue with visible light. The virus, Type A, strain 1, CANEFA of Argentine origin, was grown in tissue culture and tested in the crude and clarified state. Virus and dye were mixed and incubated together at 4 C for 45 min in the dark, or were mixed and immediately exposed to the visible light source without prior incubation together. Mixtures of crude virus and dye, under any of the experimental conditions used, did not inactivate more than 1 to 2 logs of viral infectivity when held in the dark or when exposed to light during a period of 45 min. Complete inactivation of virus was achieved when clarified virus and dye were mixed and immediately exposed to the visible light source for 15 min. Prior incubation of clarified virus and dye permitted inactivation by methylene blue only, whereas no incubation prior to exposure resulted in three of the dyes contributing to inactivation. A concentration of 6 ?g of neutral red, Toluidine Blue, methylene blue, and crystal violet was used per milliliter of virus suspension. Crystal violet was not a good viral inactivator under the conditions of the experimentation. Inactive virus induced the formation of neutralizing antibodies in adult chickens and mice. The antibody titer stimulated by the antigen treated with methylene blue and visible light was probably significant. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Fellowes, O. N.

1966-01-01

199

Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium  

NASA Astrophysics Data System (ADS)

The primary concern of this work is to study the emission characteristics of a series of chiral nematic liquid crystal lasers doped with different laser dyes (DCM, pyrromethene 580, and pyrromethene 597) at varying concentrations by weight (0.5-2 wt %) when optically pumped at 532 nm. Long-wavelength photonic band-edge laser emission is characterized in terms of threshold energy and slope efficiency. At every dye concentration investigated, the pyrromethene 597-doped lasers exhibit the highest slope efficiency (ranging from 15% to 32%) and the DCM-doped lasers the lowest (ranging from 5% to 13%). Similarly, the threshold was found to be, in general, higher for the DCM-doped laser samples in comparison to the pyrromethene-doped laser samples. These results are then compared with the spectral properties, quantum efficiencies and, where possible, fluorescence lifetimes of the dyes dispersed in a common nematic host. In accordance with the low thresholds and high slope efficiencies, the results show that the molar extinction coefficients and quantum efficiencies are considerably larger for the pyrromethene dyes in comparison to DCM, when dispersed in the liquid crystal host.

Mowatt, Carrie; Morris, Stephen M.; Song, Myoung Hoon; Wilkinson, Timothy D.; Friend, Richard H.; Coles, Harry J.

2010-02-01

200

Adsorption of cyanine dyes on AgCl crystals studied by XPS  

NASA Astrophysics Data System (ADS)

Adsorption of 3,3'-dimethyl-9-ethylthiacarbocyanine dyes with iodide or bromide counter ions showed two energy states of sulfur in the dye molecule, one is the adsorption state to AgCl substrate and the other occurs when dye molecules aggregated. Though iodide conversion occurred on KI adsorption on AgCl, the counter ion of the dye molecule did not cause halide conversion on adsorption. The counter ion was observed only after the first dye monolayer on AgCl was completed, and increased parallel with adsorbed dye amounts. On Ag-deposited quartz plate monolayer formation occurred only by dye adsorption compared by its counter ion, while only iodine adsorbed in KI adsorption.

Saijo, Hiroshi; Kitamura, Takeshi; Ohtani, Hirofumi

1986-12-01

201

In defence of 'dye therapy'.  

PubMed

Worldwide, healthcare is facing enormous problems with the continuing rise of drug-resistant infectious diseases. In view of the scarcity of new antimicrobial agents and the withdrawal of many pharmaceutical houses from the fray, alternative approaches are required. One of these is photoantimicrobial chemotherapy, which is highly effective across the range of microbial pathogens and does not suffer from resistance. However, there is a lack of uptake of this approach by healthcare providers and the pharmaceutical industry alike. It is seldom recalled that, unlike anticancer photodynamic therapy, the development of photoantimicrobial agents has evolved from the antiseptic 'dye therapy' in common use until the widespread introduction of the penicillin class in the mid-1940s. Cationic biological dyes such as methylene blue, crystal violet and acriflavine were effective in local wound therapy and today provide a sound basis for light-activated antimicrobial therapeutics. It is proposed that such 'safe' dyes are introduced as locally administered photoantimicrobials, especially in order to conserve valuable conventional antibacterial drugs. PMID:24795083

Wainwright, Mark

2014-07-01

202

Self-alignment of dye molecules in micelles and lamellae for three-dimensional imaging of lyotropic liquid crystals.  

PubMed

We report alignment of anisotropic amphiphilic dye molecules within oblate and prolate anisotropic micelles and lamellae, the basic building blocks of surfactant-based lyotropic liquid crystals. Absorption and fluorescence transition dipole moments of these dye molecules orient either parallel or orthogonal to the liquid crystal director. This alignment enables three-dimensional visualization of director structures and defects in different lyotropic mesophases by means of fluorescence confocal polarizing microscopy and two-photon excitation fluorescence polarizing microscopy. The studied structures include nematic tactoids, Schlieren texture with disclinations in the calamitic nematic phase, oily streaks in the lamellar phase, developable domains in the columnar hexagonal phase, and various types of line defects in the discotic cholesteric phase. Orientational three-dimensional imaging of structures in the lyotropic cholesterics reveals large Burgers vector dislocations in cholesteric layering with singular disclinations in the dislocation cores that are not common for their thermotropic counterparts. PMID:21598933

Liu, Qingkun; Beier, Corinne; Evans, Julian; Lee, Taewoo; He, Sailing; Smalyukh, Ivan I

2011-06-21

203

Optically controllable and focus-tunable Fresnel lens in azo-dye-doped liquid crystals using a Sagnac interferometer.  

PubMed

This study demonstrates a tunable Fresnel lens in an azo-dye-doped liquid crystal (ADDLC) film using an interference technique. One Fresnel-patterned green beam using a Sagnac interferometer irradiated the UV-illuminated ADDLC cell, yielding a concentric zone plate distribution with homeotropic and isotropic structures in bright and dark regions of the green interference pattern. The proposed Fresnel lens is polarization independent, focus tunable, and the focusing efficiency of the device can be optically controlled. PMID:21499340

Yeh, Hui-Chen; Kuo, Yi-Chieh; Lin, Shih-Hung; Lin, Jia-De; Mo, Ting-Shan; Huang, Shuan-Yu

2011-04-15

204

Single-Mode Operation of Electrotunable Laser in a Dye-Doped Nematic Liquid-Crystal Waveguide under Holographic Excitation  

NASA Astrophysics Data System (ADS)

Optically pumped distributed feedback (DFB) lasing has been demonstrated in a dye-doped nematic liquid-crystal (NLC) waveguide by holographic excitation. Utilizing NLC with a low refractive index, the single-mode operation of a laser action was realized. With an applied electric field, continuous tuning of the single-mode lasing wavelength was realized due to the change in the effective refractive index of the NLC core layer caused by the reorientation of NLC molecules.

Matsui, Tatsunosuke; Ozaki, Masanori; Yoshino, Katsumi

2003-12-01

205

Electro-tunable laser action in a dye-doped nematic liquid crystal waveguide under holographic excitation  

NASA Astrophysics Data System (ADS)

Optically pumped distributed feedback lasing has been demonstrated in a dye-doped nematic liquid crystal (NLC) waveguide by holographic excitation. The excitation was performed by two-beam interference using Lloyd mirror configuration. With an applied electric field, continuous tuning of the lasing wavelength was realized due to the change of the effective refractive index of the NLC core layer caused by the reorientation of NLC molecules.

Matsui, Tatsunosuke; Ozaki, Masanori; Yoshino, Katsumi

2003-07-01

206

Fast Optical Switching Using Oriented Cyanine Dye-Doped Nematic Liquid Crystal  

NASA Astrophysics Data System (ADS)

A cyanine dye, 2-[7-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide (NK-125), is doped in 4-cyano-4'-pentylbiphenyl (5 CB), and the mixture is sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical properties of the oriented NK-125-5CB layers are measured by the resonant femtosecond degenerate four-wave mixing (DFWM) technique at 760 nm. The third-order nonlinear optical susceptibility of one of the present samples is 5.5×10-8 esu. The slow DFWM response of the NK-125-5CB layers due to a population grating is accelerated by the increasing laser power because of amplified spontaneous emission (ASE). On the other hand, we do not observe a similar phenomenon for NK-125-polyethylene glycol (PEG-400). Oriented NK-125 molecules in nematic liquid crystals must have very high ASE efficiency. Hence the population grating in a DFWM signal disappears within about 4 ps. It is expected that NK-125-5CB can be used as a material for very fast all-optical switching.

Jin, Zhao-Hui; Li, Zhong-Yu; Kazuo, Kasatani; Hiroaki, Okamoto

2006-10-01

207

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

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.

Lippa, I. [Byron-Bergen High School, NY (United States)

1999-03-01

208

Efficient removal of triphenylmethane dyes from aqueous medium by in situ electrogenerated Fenton’s reagent at carbon-felt cathode  

Microsoft Academic Search

Fenton’s reagent (Fe2++H2O2) has been electrogenerated in situ in an undivided electrolytic cell from the effective reduction of Fe3+ and O2 at carbon-felt cathode for the treatment of aqueous solutions of four triphenylmethane dyes (TPMs), namely malachite green (MG), crystal violet (CV), methyl green (MeG) and fast green FCF (FCF), at pH 3.0 and room temperature. MG has been used

Ignasi Sirés; Elodie Guivarch; Nihal Oturan; Mehmet A. Oturan

2008-01-01

209

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

210

Photo-induced reorientation inversion in cis-enriched azo-dye doped liquid crystals in the isotropic phase  

NASA Astrophysics Data System (ADS)

Nanosecond laser pulse induced molecular reorientation in azobenzene doped liquid crystals (LCs) in the isotropic phase was studied by the optical heterodyned optical Kerr effect method. Reorientation inversion was found by artificially preparing a cis isomer enriched initial state. The interaction strength ratio of trans and cis isomers with the LC molecules was deduced based on a modified mean-field theory model. Our results provide a further understanding of the photo-induced reorientation of photo-isomerizable dye-doped LC systems.

Yang, Pei; Shan, Jiong; Liu, Liying; Xu, Lei

2009-04-01

211

Nonlinear optical property of azo-dye doped liquid crystals determined by biphotonic Z-scan technique.  

PubMed

This work investigates the optical Kerr property of azo-dye doped nematic liquid crystal films using the biphotonic Z-scan technique. The results indicate that the nonlinear effect measured using the Z-scan technique with a red light can be modulated or switched with the simultaneous application of a green light, because of photoisomerization and thermal effects, as determined by dynamic measurements. The former dominates in the early stage when the green light is applied, while the latter dominates in the later stage. PMID:19503278

Fuh, Andy Ying-Guey; Lin, Hui-Chi; Mo, Ting-Shan; Chen, Ching-Hsu

2005-12-26

212

The influence of the easy axis on laser-induced ripple structures in dye-doped liquid crystal films  

NASA Astrophysics Data System (ADS)

We have investigated the role of the easy axis in the photoalignment effect induced by an Ar+ linearly polarized laser beam on a dye-doped nematic liquid crystal cell in a pump-probe experiment. The induced permanent structure in the irradiated zones was studied using a polarizing optical microscope, and the laser-induced surface morphology was studied by atomic force microscopy. The depth of the ripple structure depends on both the pump power and the irradiated surfaces. The azimuthal anchoring energy provided by the ripple structure was evaluated and it was concluded that it varies with the cell's symmetry.

Palarie, I.; Dascalu, C.; Iacobescu, G. E.

2010-12-01

213

Simultaneous measurement of absorbance and quantum yields for photocurrent generation at dye-sensitized single-crystal ZnO electrodes.  

PubMed

It is often assumed that the photoresponse or incident photon-to-current conversion efficiency (IPCE) spectrum of a sensitized semiconductor electrode is directly correlated with the amount of sensitizing species present on the semiconductor surface. In reality, the various forms of adsorbed species, such as dye aggregates or dye molecules bound to different adsorption sites, such as terrace edges, can have significantly different electron injection yields and carrier recombination rates. To provide information about the amounts of the various adsorbed dye species and their effectiveness as sensitizers, we report the simultaneous acquisition of IPCE and attenuated total reflectance (ATR) UV-vis spectra for a thiacyanine dye bound to a single-crystal oxide semiconductor electrode surface. ZnO single crystals were fashioned into internal-reflection elements to act both as a waveguide for the internally reflected probe beam for UV-vis spectra and as the substrate for dye sensitization using dyes with distinct spectral signatures for monomers and aggregates. Strong agreement was observed between the quantum efficiency and ATR UV-vis spectra, suggesting that, under the conditions employed, both monomers and aggregates of the dye studied generate photocurrent with the same efficiency. PMID:24090190

Rowley, John G; Parkinson, B A

2013-11-12

214

Effect of some operational parameters on textile dye biodegradation in a sequential batch reactor  

Microsoft Academic Search

The combination of anaerobic and aerobic periods in the operation cycle of a Sequencing Batch Reactor (SBR) was chosen to study biological color removal from simulated textile effluents containing reactive, sulfonated, monoazo and diazo dyes, respectively, Remazol Brilliant Violet 5R and Remazol Black B. 90% color removal was obtained for the violet dye in a 24-h cycle with a Sludge

N. D Lourenço; J. M Novais; H. M Pinheiro

2001-01-01

215

Investigation of dielectric properties and diffraction efficiency enhancements caused by photothermal effect in DR9 dye-doped nematic liquid crystal  

NASA Astrophysics Data System (ADS)

In this work, we studied dielectric properties and laser-induced refractive index changes originating from photothermal effects of liquid crystal material doped with Disperse Red 9 (DR9) dye. Dye concentration is arranged to be between percentages changing from 0.2 wt.% to 1 wt.% in E63 nematic liquid crystal. Nonlinear optical properties such as diffraction efficiency ( ?) and refractive index modulation (? n) were investigated by diffraction grating measurements. It was found the diffraction efficiency of pure E63 nematic liquid crystal is 1%. As the doping amount of DR9 dye in nematic LC is increased, diffraction efficiency took higher values and the maximum diffraction efficiency of 10% was gained with E63 doped with 0.8 wt.%DR9 dye. Moreover, dielectric permittivity and dielectric anisotropy values of the samples were investigated in the frequency range of 100 Hz-10 MHz by using dielectric spectroscopy technique. It was observed that dielectric constant values of the liquid crystal material are strongly affected by doping with dye.

Köysal, O?uz; Okutan, Mustafa; Gökçen, Muharrem

2011-09-01

216

Enhanced light harvesting in dye-sensitized solar cells coupled with titania nanotube photonic crystals: a theoretical study.  

PubMed

Herein we present a theoretical analysis on the optical properties and the photocurrent enhancement of nanotube-based dye-sensitized solar cells (DSSCs) coupled with a TiO2 nanotube (NT) photonic crystal (PC). It is found that the introduction of a TiO2 nanotube PC produces both Bragg mirror effect and Fabry-Perot cavity behavior, leading to a significant enhancement of light harvesting for photons in the photonic bandgap and at the two band edges. In addition, an increased amount of surface-anchored dye due to the larger surface area in the NT PC layer also causes absorption enhancement in the whole visible spectrum. The effects of structural parameters of the PC, such as the thickness of the PC layer, the axial lattice constant, the diameter of the nanotube, and light incident angle, on the optical properties and photocurrent magnification are thoroughly studied. The optimum structural parameters are proposed, which not only provide guidance but also offer further opportunities in the design and applications of TiO2 nanotube photonic crystals. PMID:24313334

Guo, Min; Yong, Zehui; Xie, Keyu; Lin, Jia; Wang, Yu; Huang, Haitao

2013-12-26

217

Phase shifting phase contrast interferometer using a dye-doped liquid-crystal self-aligning phase modulator  

NASA Astrophysics Data System (ADS)

A new phase contrast imaging system that permits a quantitative observation of phase distribution of a general object is proposed and experimentally demonstrated. This is realized by implementing the phase shifting technique in the phase contrast imaging system. A dye-doped nematic liquid-crystal (NLC) is newly employed for this purpose as a variable phase filter in contrast to the constant phase plate employed in the conventional phase contrast microscope (PCM). The dye-doped NLC provides a practical advantage to the system that realizes an alignment-free optical system for the phase plate. The self-alignment property of the phase filter is realized by utilizing the local phase transition from the liquid-crystal to liquid, which is induced by the relatively strong incident light of the specular component of the object. In the experiment, the fundamental phase modulation property and the response of phase modulation ability were measured as a function of incident power of light. Next, the phase measurements were performed with several phase gratings and composite objects having different phase amplitudes and absorption. As an experimental result, the usefulness of the proposed method was confirmed, and the accuracy of the phase measurement was estimated to be ?/40. In addition, it was also demonstrated that the phase information could be obtained independently from the absorption component of the object.

Kadono, Hirofumi; Ohno, Kazunori; Toyooka, Satoru

2005-09-01

218

Molecular photo-oscillators based on highly accelerated heterocyclic azo dyes in nematic liquid crystals.  

PubMed

Benzothiazole-pyrrole-based azo dyes greatly enhance their thermal isomerisation rate by up to 160 times when they are under the influence of the nematic mean field yielding the LC-based photochromic oscillators with the highest oscillation frequencies reported so far (2.6 kHz at 298 K). PMID:24728417

Garcia-Amorós, Jaume; Reig, Marta; Castro, M Cidália R; Cuadrado, Alba; Raposo, M Manuela M; Velasco, Dolores

2014-05-29

219

Electrophoretic deposition of TiO2 nanoparticles using organic dyes.  

PubMed

Electrophoretic deposition method has been developed for the deposition of TiO(2) nanoparticles modified with organic dyes. Alizarin red, alizarin yellow and pyrocatechol violet dyes were used for the dispersion and charging of TiO(2) in ethanol and anodic electrophoretic deposition of TiO(2) films. The deposition yield was varied by the variation of dye concentration in suspensions and deposition time. Aurintricarboxylic acid dye was used for the deposition of TiO(2) from aqueous suspensions. It was found that thin films of pure aurintricarboxylic acid and composite aurintricarboxylic acid TiO(2) films can be obtained. The deposition yield was studied by quartz crystal microbalance. Dye film thickness was varied in the range of 0.1-2 ?m by variation in the deposition time at a constant voltage. The composition of the films and the amount of the deposited material can be varied by the variation of TiO(2) and dye concentration in suspensions and deposition time. The films were studied by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis and electron microscopy. The deposition mechanisms were discussed. The electrophoretic deposition method offers advantages for the fabrication of dye-sensitized TiO(2) films. PMID:22204967

Sun, Y; Ata, M S; Zhitomirsky, I

2012-03-01

220

The ACDF. A new class of lasing dyes  

NASA Astrophysics Data System (ADS)

Laser action has been observed without dispersion elements at blue-violet wavelengths in the new 2-amino-4-cyano-3,5- diarylfuran (ACDF) class of dyes. Spectral properties of some representative compounds are studied.

Gomez, M. Sanchez; Perez, J. M. Guerra

1981-12-01

221

Effects of surfactants on the adsorptive removal of basic dyes from water using an organomineral sorbent-iron humate.  

PubMed

The sorption of basic dyes (methylene blue, malachite green, rhodamine B, crystal violet) onto a nonconventional organomineral sorbent-iron humate-was examined in the presence of various kinds of surfactants. It was found that nonionic (Triton X-100) and cationic (cetyltrimethylammonium bromide) surfactants exhibited a relatively small effect on the dye sorption. Anionic surfactants (sodium dodecyl sulfate), on the other hand, affected (in most cases) dramatically the sorption of basic (cationic) dyes. Typically, the dye sorption was enhanced in the presence of low concentrations of anionic surfactants. At high surfactant concentrations, a steep decrease in the dye sorption was observed in some systems, probably due to the formation of micelles that solubilize the dye molecules and prevent their sorption. A model describing these experimental dependencies was proposed. The sorption of basic dyes onto iron humate may be described by the pseudo-second-order kinetic equation. Diffusion processes were identified as the main mechanisms controlling the rate of the dye sorption. PMID:16162351

Janos, Pavel; Smídová, Veronika

2005-11-01

222

Effect of Gentian Violet, Corticosteroid and Tar Preparations in Staphylococcus-aureus-Colonized Atopic Eczema  

Microsoft Academic Search

Background: In atopic eczema (AE), skin colonization with Staphylococcus aureus plays a possible role in the pathophysiology of the disease. Methods: Thirty-eight patients with AE were screened for their cutaneous colonization with S. aureus. The antibacterial and clinical efficacy of topical therapy with the antiseptic dye gentian violet, a potent glucocorticosteroid or a tar solution (liquor carbonis detergens) was evaluated

Knut Brockow; Petra Grabenhorst; Dietrich Abeck; Bernd Traupe; Johannes Ring; Udo Hoppe; Florian Wolf

1999-01-01

223

Non linearly induced self waveguiding structure in dye doped nematic liquid crystals confined in capillaries  

NASA Astrophysics Data System (ADS)

We report on experiments dealing with the propagation of a collimated laser beam in a dye doped nematic confined in a capillary of optical fiber size. The nematic is aligned in a such a way that the source beam is self focused. The behavior of the beam - focusing, multifocus regime, filamentation and undulation - already observed in larger cylindrical geometry and pure nematic is shown here to be reproduced in the dye doped medium, at much lower powers. Another feature is reported here: a stable regime looking like a waveguide appears in certain conditions, in which the beam to propagate in a narrow tube. This regime is simply modeled in terms of saturated reorientation of the nematic.

Warenghem, Marc; Henninot, J. F.; Abbate, Giancarlo

1998-06-01

224

Non linearly induced self waveguiding structure in dye doped nematic liquid crystals confined in capillaries.  

PubMed

We report on experiments dealing with the propagation of a collimated laser beam in a dye doped nematic confined in a capillary of optical fiber size. The nematic is aligned in a such a way that the source beam is self focused. The behavior of the beam - focusing, multifocus regime, filamentation and undulation - already observed in larger cylindrical geometry and pure nematic is shown here to be reproduced in the dye doped medium, at much lower powers. Another feature is reported here: a stable regime looking like a waveguide appears in certain conditions, in which the beam to propagate in a narrow tube. This regime is simply modeled in terms of saturated reorientation of the nematic. PMID:19381219

Warenghem, M; Henninot, J; Abbate, G

1998-06-01

225

STM studies on dye molecules embedded in ordered liquid crystal structures and an approach for laser-assisted scanning tunneling microscopy  

Microsoft Academic Search

Scanning tunneling microscopy, although capable of yielding very high resolution on periodic structures, very often provides only moderate resolution on singular features. Our work aims at the use of laser light to improve the identification of individual molecules. We report on scanning tunneling microscopy measurements performed on dye molecules dissolved in a liquid crystal and adsorbed onto highly oriented pyrolytic

Stefan Grafstrom; Oliver Probst; S. Dey; J. Freund; J. Kowalski; R. Neumann; M. Woertge; Gisbert Zu Putlitz

1993-01-01

226

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

SciTech Connect

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.

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

2012-03-12

227

On the possible correlation between dark conductivity, photoconductivity, and photorefractivity in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

The dc conductivity of dye-doped nematic liquid crystal cells exhibits a characteristic transition from a cubic current-voltage relationship at applied voltages smaller than about 1 V to a linear one at voltages larger than about 1.5 V. The photoconductivity, and the related photorefractive response of these cells exhibit an apparent threshold at about the same characteristic voltage: An applied voltage larger than about 1.5 V is needed to measure sizeable photocurrents and photorefractive responses. We propose a model that is consistent with all these observations. At low applied voltages, a residual space charge limits the dc current, and prevents the participation of photoexcited charge carriers to photoconductivity and photorefractivity, while at higher applied voltages, the disappearance of the residual space charge allows the manifestation of these photoinduced responses. Experimental results seem to confirm the validity of the model.

Klysubun, Prapong; Indebetouw, Guy

2002-09-01

228

Light-scattering experiments in dye-doped liquid crystals both to determine crystal parameters and to construct consistent neural network empirical physical formulas for scattering amplitudes  

NASA Astrophysics Data System (ADS)

The aim of this paper is two-fold. Firstly, static laser light-scattering amplitude measurements in azo-dye doped nematic liquid crystals (NLCs) were made versus scattering angle, temperature and applied bias voltage. Three NLC parameters were determined: the elastic constant ratios K11/ K22 by regression, phase transition temperatures, and Freedericksz voltages from the graphs. They were all doping ratio dependent. Secondly, as a novel approach, by a nonlinear universal function approximator layered feedforward neural network (LFNN) we constructed an explicit form of empirical physical formulas (EPFs) for theoretically unknown nonlinear azo-dye doped NLC scattering amplitude functions. Excellent LFNN test set (i.e. yet-to-be measured experimental data) predictions prove that the constructed LFNN-EPPs estimate unknown amplitude functions consistently. The LFFN-EPFs, too, confirmed the doping-ratio dependency. Also, comparing LFNN and regression amplitude fits, the LFNN fits were significantly better. In conclusion, physical laws embedded in the physical data can be consistently extracted by LFNN. One major potential application in the nonlinear optics domain is that these LFNN-EPFs, by differentiation, integration, minimization, etc., can be used to obtain further NLC scattering amplitude related molecular structural physical quantities. This could in turn help us to develop new nonlinear optical materials.

Yildiz, Nihat; San, Sait Eren; Polat, Ömer

2011-04-01

229

All-optical modulation in dye-doped nematic liquid crystal photonic bandgap fibers  

Microsoft Academic Search

Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate

Thomas Tanggaard Alkeskjold; Jesper Lægsgaard; Anders Bjarklev; David Sparre Hermann; Anawati Anawati; Jes Broeng; Jun Li; Shin-Tson Wu

2004-01-01

230

Fast optical switching using cyanine dye-doped nematic liquid crystal  

Microsoft Academic Search

A cyanine dye, 1,1?,3,3,3?,3?-hexamethyl-4,4?,5,5?-dibenzo-2,2?-indotricarbocyanine perchlorate (NK-2014) was doped in 4-cyano-4?-n-pentylbiphenyl (5CB), and the mixture was sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical responses of oriented NK-2014-doped 5CB were measured by the resonant femtosecond degenerate four-wave mixing (DFWM) technique at 820nm. The time resolution of the system was ca. 0.3ps (FWHM). The electronic component of third-order

Zhao-hui Jin; Zhongyu Li; Kazuo Kasatani; Hiroaki Okamoto

2007-01-01

231

Use of chromophoric ligands to visually screen co-crystals of putative protein-nucleic acid complexes.  

PubMed

Distinguishing between crystals of protein-nucleic acid complexes and those containing protein alone is a common problem in structural studies of protein-nucleic acid interactions. Currently, there are several methods available for detecting nucleic acid in crystals, including gel electrophoresis, SYBR Gold fluorescence dye staining, and methyl violet staining. However, they require either that the crystals be sacrificed or access to a fluorescence microscope. In this protocol, we describe an approach that allows direct visualization of either the presence or absence of oligonucleotides in crystals grown from solutions containing both protein and nucleic acid--labeling with the Cy5 dye. In addition to offering the advantage of being able to distinguish between crystals of complex and protein alone with the naked eye or a light microscope, crystals of covalently Cy5-labeled DNA can be directly used for X-ray diffraction data collection. PMID:21901673

Jiang, Xiaohua; Egli, Martin

2011-09-01

232

Phase Controlled Laser Interference for Tunable Phase Gratings in Dye-Doped Nematic Liquid Crystals  

NASA Astrophysics Data System (ADS)

A phase controlled multi-beam interference is applied to excite the doped liquid crystals. Control of the phase difference between the exciting beams allows the external control of the interference pattern inside the liquid crystal. The dynamic variation of the grating is made possible with a time-dependent phase change to derive the nonlinear refractive index as well as the responding speed of the material. The induced grating structure is numerically modelled with reorientational phase gratings in the liquid crystal, and the diffraction dynamics is found to be in good agreement between theoretical and experimental results.

Li, Ming; Zhang, Pei-Qing; Guo, Jing; Xie, Xiang-Sheng; Liu, Yi-Kun; Liang-Bing; Zhou, Jian-Ying; Xiang, Ying

2008-01-01

233

Nonlinear optical properties of new photosensitive smart materials based on nematic liquid crystal with H-bonded dye-polymer complex  

NASA Astrophysics Data System (ADS)

The nonlinear optical (NLO) properties of the new photosensitive heterogeneous systems based on nematic liquid crystal (LC) doped with H-bonded polymer-azo-dye complex were studied. The excitation of the heterosystem by continuous laser irradiation at 532 nm produces the refractive index variation up to 10-2 measured within the spatial profile analysis in the far field. The phenomenon could be attributed to the photoinduced transformation of the azo dye from trans to cis form that reduces the order parameter of the LC in the vicinity of the complex.

Uklein, A. V.; Vasko, A. A.; Ouskova, E. V.; Brodyn, M. S.; Gayvoronsky, V. Ya.

2013-06-01

234

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)

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.

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

2006-03-01

235

Outer Penetration Barrier of Escherichia coli K-12: Kinetics of the Uptake of Gentian Violet by Wild Type and Envelope Mutants  

PubMed Central

Wild-type strains of Escherichia coli K-12 adsorb gentian violet to the cell surface, but the dye is not transported into the cytoplasm. However, when some mutants that have an altered outer membrane are exposed to gentian violet, the dye is also found in the ribosomal fraction. The transport into the cytoplasm is inhibited at 0 C and requires that the concentration of gentian violet exceeds a threshold value. The initial rate of uptake as well as the amount of gentian violet found in the cytoplasm increases with the concentration of the dye in the medium. The rate of transport of the dye into the cytoplasm is much lower for stationary mutant cells than for exponentially growing cells. The rate of uptake into the cytoplasm increases with increasing deficiency of carbohydrate in the lipopolysaccharide (carbohydrate content lpsB > lpsA > galU). However, other components are also responsible for the barrier since an envA mutant which is not altered in the lipopolysaccharide carbohydrates show an extremely rapid uptake of the dye. The rate of uptake for the envA mutant was the highest found and the same as that of spheroplasts. Growth in the presence of agents affecting the murein sacculus, e.g., lysozyme and sublethal concentrations of penicillin, increased the rate of uptake of gentian violet. Brief treatments with tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetic acid drastically impaired the barrier function. Inhibition of protein synthesis by chloramphenicol also opened the barrier to gentian violet. In conclusion, the outer part of the bacterial envelope is a penetration barrier for gentian violet and probably also for other substances. The lipopolysaccharide, the murein and also other components are important for the function of this barrier. Resistance to gentian violet was found to be inversely correlated to the rate of penetration of the dye into the cytoplasm.

Gustafsson, Petter; Nordstrom, Kurt; Normark, Staffan

1973-01-01

236

Direct-writing of inverted domains in lithium niobate using a continuous wave ultra violet laser.  

PubMed

The inversion of ferroelectric domains in lithium niobate by a scanning focused ultra-violet laser beam (lambda = 244 nm) is demonstrated. The resulting domain patterns are interrogated using piezoresponse force microscopy and by chemical etching in hydrofluoric acid. Direct ultra-violet laser poling was observed in un-doped congruent, iron doped congruent and titanium in-diffused congruent lithium niobate single crystals. A model is proposed to explain the mechanism of domain inversion. PMID:18542312

Muir, A C; Sones, C L; Mailis, S; Eason, R W; Jungk, T; Hoffman, A; Soergel, E

2008-02-18

237

Random lasing and weak localization of light in dye-doped nematic liquid crystals.  

PubMed

The first observation of random laser action in a partially ordered, optically anisotropic nematic liquid crystal with long-range dielectric tensor fluctuations is reported. Above a given pump power the fluorescence curve collapses and the typical narrowing and explosion effect leads to discrete sharp peaks. The unexpected surviving of interference effects in recurrent multiple scattering provide the required optical feedback for lasing in nematics. Coherent backscattering of light waves in orientationally ordered nematic liquid crystals manifests a weak localization of light which strongly supports diffusive laser action in presence of gain medium. Intensity fluctuations of the speckle-like emission pattern indicate the typical spatio-temporal randomness of diffusive laser emission. A comparison of the laser action is reported for systems with different order degree: fully disordered semiconductor powders, self-ordered cholesterics and partially ordered nematic liquid crystals. PMID:19529143

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

2006-08-21

238

Random lasing and weak localization of light in dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

The first observation of random laser action in a partially ordered, optically anisotropic nematic liquid crystal with long-range dielectric tensor fluctuations is reported. Above a given pump power the fluorescence curve collapses and the typical narrowing and explosion effect leads to discrete sharp peaks. The unexpected surviving of interference effects in recurrent multiple scattering provide the required optical feedback for lasing in nematics. Coherent backscattering of light waves in orientationally ordered nematic liquid crystals manifests a weak localization of light which strongly supports diffusive laser action in presence of gain medium. Intensity fluctuations of the speckle like emission pattern indicate the typical spatio-temporal randomness of diffusive laser emission. A comparison of the laser action is reported for systems with different order degree: fully disordered semiconductor powders, self-ordered cholesterics and partially ordered nematic liquid crystals.

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

2006-08-01

239

Light-controlled electric Freedericksz threshold in dye doped liquid crystals  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

240

Photo-orientation of liquid crystals due to light-induced desorption and adsorption of dye molecules on an aligning surface.  

PubMed

We show that adsorption of dye molecules control the light-induced alignment of dye-doped nematic liquid crystal (LC) on a nonphotosensitive polymer surface. The dependencies of light-induced twist structures on exposure, thermal baking, thickness, and aging before irradiation of the LC cells allowed us to propose the following mechanism for the alignment. Before irradiation, the "dark"-adsorbed layer on the tested surface is formed from dye molecules predominantly aligned along the initial direction of the director. Irradiation of the cell with linearly polarized light produces an additional layer with different orientational ordering of dye molecules. The final easy axis is determined by the competition of "dark" and light-induced contributions to anchoring and is aligned between the "dark" easy axes and polarization of the light. For quantitative interpretation, we apply the tensor model of anchoring and assume that the photoalignment in the mesophase is a cumulative effect of the light-induced anchoring on the background of the already existing anisotropic "dark" dye layer. PMID:11735947

Ouskova, E; Reznikov, Y; Shiyanovskii, S V; Su, L; West, J L; Kuksenok, O V; Francescangeli, O; Simoni, F

2001-11-01

241

Photo-orientation of liquid crystals due to light-induced desorption and adsorption of dye molecules on an aligning surface  

NASA Astrophysics Data System (ADS)

We show that adsorption of dye molecules control the light-induced alignment of dye-doped nematic liquid crystal (LC) on a nonphotosensitive polymer surface. The dependencies of light-induced twist structures on exposure, thermal baking, thickness, and aging before irradiation of the LC cells allowed us to propose the following mechanism for the alignment. Before irradiation, the ``dark''-adsorbed layer on the tested surface is formed from dye molecules predominantly aligned along the initial direction of the director. Irradiation of the cell with linearly polarized light produces an additional layer with different orientational ordering of dye molecules. The final easy axis is determined by the competition of ``dark'' and light-induced contributions to anchoring and is aligned between the ``dark'' easy axes and polarization of the light. For quantitative interpretation, we apply the tensor model of anchoring and assume that the photoalignment in the mesophase is a cumulative effect of the light-induced anchoring on the background of the already existing anisotropic ``dark'' dye layer.

Ouskova, E.; Reznikov, Yu.; Shiyanovskii, S. V.; Su, L.; West, J. L.; Kuksenok, O. V.; Francescangeli, O.; Simoni, F.

2001-11-01

242

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

PubMed

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 ?-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 of the 17(2)-position with esterified hydrophilic or hydrophobic chains, dendron-wedge substituents, and chromophores having complementary optical properties such as naphthalene bisimides (NBIs) is used to modulate the self-assembly of ZnChl dyes. The resulting assemblies exhibit enhanced charge transport and energy transfer abilities. We have used UV/vis, circular dichroism (CD), fluorescence spectroscopy, and dynamic light scattering (DLS) for the characterization of these assemblies in solution. In addition, we have studied assembly morphologies by atomic force microscopy (AFM), scanning tunneling microscopy (STM), transmission electron microscopy (TEM), and cryogenic-TEM. Crystallographic techniques such as powder X-ray and solid-state NMR have been used to explain the precise long- and short-range packing of dyes in these assemblies. Finally, functional properties such as charge and energy transport have been explored by pulse radiolysis time-resolved microwave conductivity (PR-TRMC), conductive AFM, and time-resolved fluorescence spectroscopy. The design principles discussed in this Account are important steps toward the utilization of these materials in biosupramolecular electronics and photonics in the future. PMID:23865851

Sengupta, Sanchita; Würthner, Frank

2013-11-19

243

Polarization-dependent nonlinear phase contrast by using dye-doped nematic liquid crystals  

NASA Astrophysics Data System (ADS)

Nonlinear phase contrast microscopy is an optical technique that uses an intensity-dependent refractive index material to produce high-contrasted images of transparent specimens. Earlier proposal of liquid crystals as phase filters for phase contrast applications used optically addressed spatial light modulators fabricated with photoconductive film. Here, we propose the use of a simpler planar nematic liquid crystal cell doped with 1% wt methyl red. Owing to their polarization dependent enhancement factor a tunable phase filter can be photoinduced efficiently. Thus, images of different degree of contrast (and even contrast reversal) can be obtained either by rotating the polarization vector. All optical real-time imaging of dynamic events can be performed and image processing such as edge enhancement is demonstrated.

Porras-Aguilar, Rosario; Iturbe-Castillo, Marcelo D.; Ramirez-San-Juan, Julio C.; Baldovino-Pantaleon, Oscar; Sanchez de la Llave, David; Ramos-Garcia, Ruben; Arroyo-Carrasco, Luis

2008-08-01

244

Analysis of Optically Induced Refractive Index Change of Dye-Doped Nematic Liquid Crystals  

NASA Astrophysics Data System (ADS)

We present a detailed quantitative experimental and theoretical study of laser induced refractive index changes in nematic liquid crystals doped with methyl-red, disperse red and azobenzene liquid crystal. These refractive index changes, originating from molecular reorientations and order parameter modification, are measured by means of intensity and polarization grating methods. The reorientation of the director axis is calculated from polarization dependence of the probe beam diffraction efficiency. The contribution of each effect to the total diffraction efficiency is quantitatively evaluated. In general, we found that the reorientational direction of the NLC molecules depends on the dopants as well as the nature of the pump beam polarization state. In methyl-red doped samples, the laser induced reorientation mechanism dominates, whereas order parameter modification plays a major role in the others.

Shishido, A.; SHIH, M.-Y.; Khoo, I. C.

245

Small volume excitation and enhancement of dye fluorescence on a 2D photonic crystal surface.  

PubMed

We demonstrate an easy-to-implement scheme for fluorescence enhancement and observation volume reduction using photonic crystals (PhCs) as substrates for microscopy. By normal incidence coupling to slow 2D-PhC guided modes, a 65 fold enhancement in the excitation is achieved in the near field region (100 nm deep and 1 microm wide) of the resonant mode. Such large enhancement together with the high spatial resolution makes this device an excellent substrate for fluorescence microscopies. PMID:20389379

Estrada, L C; Martinez, O E; Brunstein, M; Bouchoule, S; Le-Gratiet, L; Talneau, A; Sagnes, I; Monnier, P; Levenson, J A; Yacomotti, A M

2010-02-15

246

Investigation of multiple holographic recording in azo-dye-doped nematic liquid-crystal film.  

PubMed

We report multiple holographic recording and optical address recognition schemes in Methyl Red-doped liquid-crystal film without an applied electric field. Ten gratings are recorded at a single location of a 5 mm2 area by using optical multiplexing methods, and the diffraction efficiencies are studied for multiplexed gratings. Diffraction behavior of angular and peristrophic multiplexed gratings is discussed, and two methods that involve recording angles and peristrophic rotation angles are presented for optical recognition. PMID:19488113

Gao, Hongyue; Liu, Jianhua; Gan, Fuxi; Ma, Bo

2009-06-01

247

Photovoltage enhancement from cyanobiphenyl liquid crystals and 4-tert-butylpyridine in Co(II/III) mediated dye-sensitized solar cells.  

PubMed

Two cyanobiphenyl liquid crystals (LCs), 5CB (4-cyano-4'-pentylbiphenyl) and 8CB (4-cyano-4'-octylbiphenyl), are introduced as additives into Co(II/III) electrolytes for dye-sensitized solar cells (DSCs). An electrolyte containing a combination of these LCs and 4-tert-butylpyridine (TBP) exhibits higher photovoltage than one with only TBP, resulting in higher power conversion efficiency. PMID:23985828

Koh, Teck Ming; Li, Hairong; Nonomura, Kazuteru; Mathews, Nripan; Hagfeldt, Anders; Grätzel, Michael; Mhaisalkar, Subodh G; Grimsdale, Andrew C

2013-10-14

248

Low-threshold self-pumped phase conjugation of an Ar+-laser beam by using a dye-doped nematic liquid crystal  

NASA Astrophysics Data System (ADS)

Investigations of self-pumped phase conjugation (SPPC) of a low power cw-Ar-laser by using a dye-doped nematic liquid crystal are reported. The phase conjugated signal was generated by stimulated thermal scattering. The threshold power at a wavelength of 514.5 nm was about 30 mW and the maximum power-reflectivity was up to 1%. The ability to compensate phase aberrations has been demonstrated.

Antipov, O. L.; Eichler, Hans J.; MacDonald, R.; Meindl, P.

1996-04-01

249

Decolorization of Alizarin Red and other synthetic dyes by a recombinant laccase from Pichia pastoris.  

PubMed

A cDNA encoding for a laccase was isolated from the white-rot fungus Lenzites gibbosa by RT-PCR and expressed in the Pichia pastoris. The laccase native signal peptide efficiently directed the secretion of the recombinant laccase in an active form. Factors influencing laccase expression, such as pH, cultivation temperature, copper concentration and methanol concentration, were optimized. The recombinant enzyme was purified to electrophoretic homogeneity, and was estimated to have a MW of ~61.5 kDa. The purified enzyme behaved similarly to the native laccase produced by L. gibbosa and efficiently decolorized Alizarin Red, Neutral Red, Congo Red and Crystal Violet, without the addition of redox mediators. The decolorization capacity of this recombinant enzyme suggests that it could be a useful biocatalyst for the treatment of dye-containing effluents. This study is the first report on the synthetic dye decolorization by a recombinant L. gibbosa laccase. PMID:24078122

Zheng, Miaomiao; Chi, Yujie; Yi, Hongwei; Shao, Shuli

2014-01-01

250

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

PubMed

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 ?g L(-1), and the enrichment factor (EF) 267 was obtained. Detection limit was 1.51 ?g 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

Davudabadi Farahani, Malihe; Shemirani, Farzaneh

2013-10-01

251

Increasing manganese peroxidase production and biodecolorization of triphenylmethane dyes by novel fungal consortium.  

PubMed

A fungal consortium-SR consisting of Trametes sp. SQ01 and Chaetomium sp. R01 was developed for decolorizing three kinds of triphenylmethane dyes, which were decolorized by individual fungi with low efficiencies. The fungal consortium-SR produced 1.3 U ml(-1) of manganese peroxidase, 5.5 times higher than that produced by the monoculture of Trametes sp. SQ01, and decolorized Crystal Violet, Coomassie Brilliant Blue G250 (CBB G250) and Cresol Red. The fungal consortium-SR had a decolorization rate of 63-96%, much higher than that of the monoculture of strain SQ01 (38-72%). In consortium-SR, the higher efficiencies of decolorization of Crystal Violet and CBB G250 were obtained when they added to the culture after 4d of mixed cultivation rather than at the beginning of cultivation. Cresol Red was the exception. It is suggested that the consortium-SR has great potential for decolorizing triphenylmethane dyes. PMID:21920734

Yang, Xiuqing; Wang, Jingren; Zhao, Xiaoxia; Wang, Qi; Xue, Rui

2011-11-01

252

Simultaneous exhibition of positive and negative nonlinear refractive index in dye-doped liquid crystal in a Z-scan experiment  

NASA Astrophysics Data System (ADS)

Dye-doped nematic liquid crystal samples where the vector director is not pre-aligned exhibits simultaneously positive and negative nonlinear refractive index under cw illumination at room temperature, regardless the polarization state of the illuminating beam. However, its relative contributions are polarization dependent. Experimental Z-scan curves for 100 ?m thick methyl red doped 5CB nematic liquid crystals, demonstrate that negative nonlinearity is an order of magnitude larger than the positive. The polarization state of the transmitted beam is change to elliptical carrying information about the positive and negative nonlinearities.

Iturbe-Castillo, M. D.; Ramos-García, R.; Rodriguez-Rosales, A. A.

2006-09-01

253

Influence of aggregation on the optical spectra of a polymethine dye in single crystals  

NASA Astrophysics Data System (ADS)

Reflectivity spectra of several crystal faces of bis(dimethylamino)-heptamethinium perchlorate, BDH +ClO 4-, and bis(dimethylamino)-heptamethinium tetraphenylborate, BDH +BPh 4-, have been analyzed with a polariton model to derive transition energies and strength of the molecular ? ? ? ? transitions. Different stacking leads to considerable shift of the transitions with respect to spectra in solution in qualitative agreement with models based on dipolar interaction. The contribution of these transitions to the dielectric susceptibility is very different in both materials. It is shown that this is solely due to the packing of the molecules while their large oscillator strength f=5.5 remains the same. Finestructure related to molecular vibrations is absent in the spectra of the densily packed BDH +ClO 4- which is interpreted by fast energy loss of polariton resonances.

Dähne, L.; Horvath, A.; Weiser, G.

1995-06-01

254

Linear dichroism studies of binding site structures in solution. Complexes between DNA and basic arylmethane dyes.  

PubMed

The interaction between B-form DNA and twelve cationic triaryl-methane dyes was studied with respect to optical properties and stabilities, using linear dichroism (LD) and aqueous two-phase partition techniques. Monovalent dyes derived from crystal violet as a rule form a single strong complex (K1 ca 10(5) M-1; site density per nucleotide base n1 ca 0.1 at 0.1M ionic strength) in which the plane of the dye is at an angle of less than 50 degrees to the local DNA helix axis. The complex with fuchsin is weaker (10(4) M-1) but can be explained by a similar orientation. For some of the dyes (those with pseudo-C2v symmetry) the angular orientations of two molecule-fixed axes can be obtained. For the divalent methyl green a second complex appears to be formed at low ionic strength. Methyl green (and to some extent 2-thiophene green and malachite green) show exciton splitting in the LD spectrum and circular dichroism assignable to exciton coupling between transition dipoles roughly parallel to the helical strands, indicating a dye-dye interaction. The optical data, supported by fitting experiments with space-filling models, suggests a general structure for the binding site. The dye is not intercalated but is bound to exposed hydrophobic regions in the major groove. The ligand is in part (the charged amino groups) in contact with the phosphoribose chain but its main surface lies against the hydrophobic base-pair stack. For a diphenylmethane dye, Michler's hydro blue, a perpendicular orientation was observed, possibly due to intercalation. PMID:647099

Nordén, B; Tjerneld, F; Palm, E

1978-03-01

255

Adsorption of dyes from aqueous solutions on activated charcoal  

Microsoft Academic Search

Adsorption of industrially important dyes namely bromophenol blue, alizarine red-S, methyl blue, methylene blue, eriochrome black-T, malachite green, phenol red and methyl violet from aqueous media on activated charcoal has been investigated. The effect of shaking time, pH and temperature on the adsorption behaviour of these dyes has been studied. It was noted that adsorption of all the dyes on

Muhammad J. Iqbal; Muhammad N. Ashiq

2007-01-01

256

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

NASA Astrophysics Data System (ADS)

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.

Yildiz, Nihat; San, Sait Eren; Köysal, O?uz

2010-09-01

257

Quinoid conjugated dye designed for efficient sensitizer in dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

Paraquinoid rings are introduced in the ?-conjugation of all-organic donor-?-acceptor dyes as sensitizer in dye sensitized solar cells, to drastically shift optical response from violet-blue to near-infrared and to significantly enhance photoabsorption. Taking Y1 as a model, real time electron dynamics simulations based on time-dependent density functional theory confirm that paraquinoid conjugation maintains high thermal stability and ultrafast electron-hole separation at ambient temperature.

Jiao, Yang; Ma, Wei; Meng, Sheng

2013-10-01

258

Compact femtosecond system based on dye amplifiers pumped by a multichannel N2 longitudinal discharge laser  

NASA Astrophysics Data System (ADS)

New approach to construction of the compact femtosecond system is proposed. This system can provide less than 50 fs light pulses with up to 100 (mu) J energy and more than 500 Hz repetition rate in visible, near UV and IR spectral regions. There are some essential advantages of this system in comparison with traditional solid state amplifiers schemes. First of them is a possibility of self-selection of incident femtosecond pulses, second is a self isolation of amplifier from master oscillator. Than, weak self phase modulation and chirp broadening of pulses in thin dye cells which promise us to use simple prism pulse compressor, and finely is an amplification second harmonic radiation (violet-blue radiation). Amplified violet-blue femtosecond pulses can be used than for pumping of optical parametric oscillators (OPO) and amplifiers (OPA) on the base of LBO, BBO or LiJO3 crystals. Femtosecond pulses at the signal frequency from that OPO can be also amplified in multipass dye cells, pumped by the same N2 laser. Because beams in channels are simultaneously, it not need to use in this scheme start discharge electronic synchronization systems. Amplifiers parameters estimates give reason to expect that this version of femtosecond system will have smaller sizes and price in comparison with well known existing now on the market femtosecond systems, which provide femtosecond pulses less than 50 fs, with energy up to 100 (mu) J and repetition rate more than 500 Hz in visible, near UV and IR spectral regions.

Bondarev, B. V.; Ishchenko, V. N.; Kochubei, S. A.; Kukarin, S. V.; Sorokin, V. B.

1998-10-01

259

Low-cost and effective phenol and basic dyes trapper derived from the porous silica coated with hydrotalcite gel.  

PubMed

Novel low-cost and effective adsorbents of phenol and basic dyes were made by coating amorphous silica with hydrotalcite (HT) gel followed by soaking in alkaline solution, and the surface basic-acidic properties of resulting composites were evaluated by CO(2)-TPD, Hammett indicator method and NH(3)-TPD, respectively. Both BET surface area and microporous surface area of the composites were increased after they were soaked with alkaline solution; meanwhile the center of pore size distribution was changed from 9 to 3-4 nm. These composites efficiently captured phenol in gaseous and liquid phases, superior to mesoporous silica such as MCM-48 or SBA-15 and zeolite NaY, and the equilibrium data of gaseous adsorption could be well fitted to Freundlich model. These modified silicas also exhibited high adsorption capacity forward basic dyes such as crystal violet (CV) and leuco-crystal violet (LCV), reaching the adsorption equilibrium within 1 h and offering a new material for environment protection. PMID:21458822

Tao, Yu Fei; Lin, Wei Gang; Gao, Ling; Yang, Jin; Zhou, Yu; Yang, Jia Yuan; Wei, Feng; Wang, Ying; Zhu, Jian Hua

2011-06-15

260

New liquid crystal-embedded PVdF- co -HFP-based polymer electrolytes for dye-sensitized solar cell applications  

Microsoft Academic Search

Liquid crystal (LC; E7 and\\/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained\\u000a 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine (I\\u000a 2), which participate in theI\\u000a 3\\u000a ? \\/I\\u000a ? redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and

G. Vijayakumar; Meyoung Jin Lee; Myungkwan Song; Sung-Ho Jin; Jae Wook Lee; Chan Woo Lee; Yeong-Soon Gal; Hyo Jin Shim; Yongku Kang; Gi-Won Lee; Kyungkon Kim; Nam-Gyu Park; Suhkmann Kim

2009-01-01

261

Electronic structure of N3 DYE molecules on the ZnO single crystal and epitaxial film surfaces  

NASA Astrophysics Data System (ADS)

Most dye-sensitized solar cells use TiO2 nanoparticle films as the electrode, but ZnO offers an interesting alternative. We have used direct and inverse photoemission to measure the occupied and unoccupied electronic states, and their alignment with the band edges of the substrate, of N3 dye adsorbed on ZnO(0001), ZnO(11-2), epitaxial ZnO a-plane film surfaces, and ZnO nanopillars. As the unoccupied states of ZnO are of sp-character and of relatively low cross section, the LUMO of the dye is easily observed. Samples were prepared and passivated with a pivalate layer in UHV, then sensitized in air in a solution of N3 dye in acetonitrile. As opposed to the case of the TiO2(110) surface, STM measurements indicate that the pivalic acid does. From UPS, the N3 HOMO is found at ˜0.8 eV above the ZnO valence band edge, and the LUMO is found ˜1.5 eV above the conduction band edge for the epifilm. Differences in dye adsorption and orbital alignment for these different ZnO surfaces will be discussed.

Theisen, Jean-Patrick; Bersch, Eric; Rangan, Sylvie; Lu, Yicheng; Bartynski, Robert

2008-03-01

262

The effects of external applied voltage on the nonlinear optical properties of a dye-doped nematic liquid crystal by using a single beam  

NASA Astrophysics Data System (ADS)

We report the experimental data of typical liquid crystals (6CHBT and w1680) in the nematic phase doped with and without Sudan dyes. We investigated the effect of an ac-applied voltage on the nonlinear behavior of dye doped liquid crystal (DDLC). The z-scan technique is used to measure the amplitude and the sign of the nonlinear refractive indices DDLC. The amplitude of negative nonlinear refractive indices was (~10-5cm2/W). The nonlinear absorption coefficient ? of DDLC was measured by using open aperture z- scan technique. Also the optical limiting (OL) response of DDLC was obtained. The novel effects on the far-field diffraction patterns of a Gaussian beam were depended on the external applied field. The measurements were performed using a CW He:Ne laser and CW Nd:Yag laser tuned at 632.8 nm and 532 nm, respectively. Also Gaussian beam propagated through a thin cell (sample thickness =11.8 ?m).

Majles Ara, M. H.; Bahramian, R.; Abolhasani, M.

2008-11-01

263

Geopolymeric adsorbents from fly ash for dye removal from aqueous solution  

SciTech Connect

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.

Li, L.; Wang, S.B.; Zhu, Z.H. [Curtin University of Technology, Perth, WA (Australia). Dept. of Chemical Engineering

2006-08-01

264

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

PubMed

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 degrees 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 producing 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. PMID:16626729

Li, Lin; Wang, Shaobin; Zhu, Zhonghua

2006-08-01

265

Chemical characterization and toxicologic evaluation of airborne mixtures: chemical characterization of combusted inventory red and violet smoke mixes  

SciTech Connect

Red and violet smoke grenades (Grenade, Hand, Smoke, M18) were combusted within canvas tents and the combustion products were sampled and analyzed. Uncombusted red and violet smoke mixes from the same lots used to fill the combusted grenades were also analyzed. Approximately ten percent of the major dye component of the red smoke mix, methylaminoanthraquinone (MAA) was converted to aminoanthraquinones (1-AA and 2-AA). The violet smoke mix was formulated to contain 1,4-diamino-2,3-dihydroanthraquinone (DAA) and MAA. Upon combustion the DAA was converted almost completely to diaminoanthraquinone (DAA) which was a minor constituent of the uncombusted mix. As in the combusted red smoke mix, it was found that MAA was partially converted to aminoanthraquinones.

Rubin, I.B.; Buchanan, M.V.; Moneyhun, J.H.

1982-10-01

266

Dye-Sensitized Approaches to Photovoltaics  

NASA Astrophysics Data System (ADS)

Sensitization of wide band-gap semiconductors to photons of energy less than the band-gap is a key step in two technically important processes - panchromatic photography and photoelectrochemical solar cells. In both cases the photosensitive species is not the semiconductor - silver halide or metal oxide - but rather an electrochemically active dye. The gap between the highest occupied molecular level (HOMO) and the lowest unoccupied molecular level (LUMO) is less than the band-gap of the semiconductor with which it is associated. It can therefore absorb light of a wavelength longer than that to which the semiconductor itself is sensitive. The electrochemical process is initiated when the dye molecule relaxes from its photoexcited level by electron injection into the semiconductor, which therefore acts as a photoanode. If the dye is in contact with a redox electrolyte, the negative charge represented by the lost electron can be recovered from the reduced state of the redox system, which in return is regenerated by charge transfer from a cathode. An external load completes the electrical circuit. The system therefore represents a conversion of the energy of absorbed photons into an electrical current by a regenerative device in every functional respect analogous to a solid-state photovoltaic cell. As in any engineering system, choice of materials, their optimization and their synergy are essential to efficient operation. While a semiconductor-electrolyte contact is analogous to a Schottky contact, in that a barrier is established between two materials of different conduction mechanism, with the possibility of optical absorption, charge carrier pair generation and separation, it should be remembered that the photogenerated valence band hole in the semiconductor represents a powerful oxidizing agent. Given that the band-gap is related to the strength and therefore the stability of chemical bonding within the semiconductor, for narrow-gap materials the most likely 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 preferred dye system is inspired by the natural processes involving chlorophyll, the coloring

Grätzel, Michael

2008-03-01

267

BRIEF COMMUNICATIONS: Excitation of dye solutions and their mixtures by copper vapor laser radiation  

Microsoft Academic Search

Laser action is reported from ethanol solutions of uranin, rhodamine 6G, rhodamine B, cresyl violet, and their mixtures pumped by copper vapor laser radiation. The energy and spectral characteristics of the dye lasers are presented. The characteristics of excitation of individual dyes by two-frequency copper laser radiation are noted.

L. V. Masarnovskii; A. N. Soldatov; V. B. Sukhanov

1979-01-01

268

Adsorption behaviors of acid and basic dyes on crosslinked amphoteric starch  

Microsoft Academic Search

Crosslinked amphoteric starch with carboxymethyl and quaternary ammonium groups is investigated as an adsorbent for removal of both acid and basic dyes in solution. Acid Light Yellow 2G, Acid Red G, Methyl Green and Methyl Violet were used to study the adsorption behaviors under various parameters such as pH, dose of amphoteric starches, initial dye concentration, adsorption time and adsorption

Shimei Xu; Jingli Wang; Ronglan Wu; Jide Wang; Hong Li

2006-01-01

269

Potential use of low-cost lignocellulosic waste for the removal of direct violet 51 from aqueous solution: equilibrium and breakthrough studies.  

PubMed

An efficient biosorbent, sugarcane bagasse was used in native, HCl-treated, and Na-alginate immobilized form for the removal of Direct Violet 51 dye from aqueous solutions. Batch study was performed to optimize important process parameters, such as pH, contact time, biosorbent dose, initial dye concentration, and temperature. Removal of Direct Violet 51 was found to be favorable at pH 2 with the biosorbent dose of 0.05 g. Biosorption process was found to be exothermic in nature. Maximum dye biosorption (39.6 mg/g) was achieved by using HCl-treated biomass. The pseudo-second-order kinetic and Langmuir adsorption isotherm models showed best fitness to the experimental data. Thermodynamic study was also performed to determine the feasibility of biosorption process. Continuous mode study was performed to optimize the important process parameters, such as bed height, flow rate, and initial dye concentration for maximum removal of Direct Violet 51 dye. The higher bed height, low flow rate, and high initial dye concentration were found to be the better conditions for maximum dye biosorption (17.28 mg/g). The linearized form of the Thomas model equation fitted well to the experimental data. The bed depth service time model was used to express the effect of bed height on breakthrough curves. Characterization of biosorbent was performed by scanning electron microscopy and Fourier transform infrared (FT-IR) analysis. The FT-IR spectral analyses showed the involvement of hydroxyl, carbonyl, and carboxyl groups in biosorption process. These results indicated that sugarcane bagasse biomass could be used as a novel biosorbent for the removal of Direct Violet 51 dye from real textile and related industries. PMID:24468968

Sadaf, Sana; Bhatti, Haq Nawaz; Nausheen, Sana; Noreen, Saima

2014-05-01

270

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

PubMed Central

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.

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

2005-01-01

271

A Novel Carboxyethyltin Functionalized Sandwich-type Germanotungstate: Synthesis, Crystal Structure, Photosensitivity, and Application in Dye-Sensitized Solar Cells.  

PubMed

A novel sandwich-type germanotungstate [C(NH2)3]10[Mn2{Sn(CH2)2COOH}2(B-?-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

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

2014-05-28

272

Dynamic evolution of light-induced orientation of dye-doped liquid crystals in liquid phase studied by time-resolved optically heterodyned optical Kerr effect technique  

NASA Astrophysics Data System (ADS)

Transient evolution of light-induced molecular reorientation both in 1-amino-anthraquinone (1AAQ) dye and azobenzene doped isotropic liquid crystals (LCs) were studied by time-resolved optically heterodyned optical Kerr effect method. The results give clear direct experimental proof that under short pulse (30 ps) excitation, LC molecules orientate toward the excitation light polarization direction in the 1AAQ/LC system. However, LC molecular orientation becomes orthogonal to the light polarization in azobenzene/LC system. Time-resolved excited-state absorption of 1AAQ and wavelength dependent excited-state absorption of azobenzene were also observed and their contributions to the early dynamics of the third order optical responses of the two systems were confirmed. A simplified two-level mean-field theory was derived to reveal the intensity dependence of orientation enhancement factor in azobenzene/LC system considering the photoisomerization process.

Yang, Pei; Liu, Liying; Xu, Lei

2008-02-01

273

Synthesis and application of TiO2 single-crystal nanorod arrays grown by multicycle hydrothermal for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned TiO2 nanorod arrays (NRs) are grown on the fluorine-doped tin oxide (FTO) substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED). It is found that dye-sensitized solar cells (DSSCs) assembled by the as-prepared TiO2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.

Zhu, Jian-Jing; Zhao, Yu-Long; Zhu, Lei; Gu, Xiu-Quan; Qiang, Ying-Huai

2014-04-01

274

Tunable laser action in a dye-doped nematic liquid-crystal waveguide under holographic excitation based on electric-field-induced TM guided-mode modulation  

NASA Astrophysics Data System (ADS)

Electrically tunable laser action has been demonstrated in a dye-doped nematic liquid-crystal (NLC) waveguide by holographic excitation. The optical feedback was provided by the distributed feedback induced by two-beam interference by use of the Lloyd mirror configuration. Electrical tuning of the lasing wavelength was realized owing to the change of the effective refractive index of the NLC core layer caused by the reorientation of NLC molecules. On the basis of a waveguiding mode theory, numerical analysis of a TM guided mode in the presence of an applied electric field was performed, and field-induced tuning of the lasing wavelength was investigated in detail. Prospects for the realization of a single-mode operation and tuning of the lasing wavelength were also shown.

Matsui, Tatsunosuke; Ozaki, Masanori; Yoshino, Katsumi

2004-09-01

275

Optically band-tunable color cone lasing emission in a dye-doped cholesteric liquid crystal with a photoisomerizable chiral dopant  

SciTech Connect

This work demonstrates the feasibility of an optically band-tunable color cone lasing emission (CCLE) based on a dye-doped cholesteric liquid crystal with a photoisomerizable chiral dopant. Experimental results indicate that the lasing band of the formed CCLE can be tuned optically among various color regions by adjusting the UV irradiated fluence. The optical band tunability of the laser is attributed to the presence of two chiral agents with twisting powers of opposite signs in the cell and the UV-irradiation-induced decrease of the right-handed twisting power of the photoisomerizable chiral dopant via trans->cis isomerization, subsequently inducing the other chiral agent to reduce the structural pitch of the cell. Total tunable wavelength range of the laser exceeds 100 nm. Moreover, the band-tunable laser exhibits a high spectral stability under illumination of a visible light or thermal treatment.

Lee, C.-R.; Lin, S.-H.; Ku, H.-S.; Huang, C.-Y.; Ji, T.-D. [Institute of Electro-Optical Science and Engineering and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Liu, J.-H. [Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Yang, P.-C. [Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 320, Taiwan (China); Yeh, H.-C. [Graduate Institute of Electro-Optical Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung 811, Taiwan (China)

2010-03-15

276

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

PubMed

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

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

2012-01-01

277

Sorption for removing Lauths Violets in aqueous solutions by chemically crosslinked poly(AAm-co-SA) hydrogels  

Microsoft Academic Search

Summary Superswelling poly(acrylamide-co-sodium acrylate) hydrogels were prepared by free radical polymerization in aqueous solution of acrylamide (AAm) with sodium acrylate (SA) as comonomer and a multifunctional crosslinker such as trimethylolpropane triacrylate (TMPTA). In the sorption studies, binding of a cationic dye such as Lauths Violet (Thionin, LV) onto chemically crosslinked poly(AAm-co-SA) hydrogels has been investigated. Sorption of LV onto poly(AAm-co-SA)

Erdener Karada?; Ömer Bar?? Üzüm

2005-01-01

278

Combined effects of sugarcane bagasse extract and synthetic dyes on the growth and bioaccumulation properties of Pichia fermentans MTCC 189.  

PubMed

Bioaccumulation of synthetic dyes viz. Acid Blue 93, Direct Red 28 and Basic Violet 3 by growing cells of yeast, Pichia fermentans MTCC 189 was investigated in growth media prepared from sugarcane bagasse extract. The maximum dye bioaccumulation was determined at pH 5.0 for all the dyes tested. Two kinetic models viz. Noncompetitive and Uncompetitive models were tested in order to determine the toxic effects of dyes on the specific growth rate of P. fermentans MTCC 189. Basic Violet 3 was found to be more toxic than the other two dyes. The combined effects of sugarcane bagasse extract and initial Basic Violet 3 dye concentrations on the specific growth rate and dye bioaccumulation efficiency of P. fermentans MTCC 189 was investigated and optimized using Response Surface Methodology (RSM). A 2(2) full factorial central composite design was successfully used for analysis of results. The optimum combination predicted via RSM confirmed that P. fermentans MTCC 189 was capable of bioaccumulating Basic Violet 3 dye upto 69.8% in the medium containing 10 mg/L of dye and 24 g/L sugar extracted from sugarcane bagasse. PMID:20692093

Das, Devlina; Charumathi, D; Das, Nilanjana

2010-11-15

279

Fluorescence quantum yield of cresyl violet in methanol and water as a function of concentration  

SciTech Connect

Photothermal spectroscopies and fluorimetry have been used to determine absolute and relative fluorescence quantum yields for cresyl violet perchlorate in methanolic and aqueous solutions as a function of concentration. The concentration dependence of the fluorescence quantum yield is found to be significant and cannot be ignored as in past studies. The values of the fluorescence quantum yield are found to be affected by inner filter effects. In aqueous solution, the fluorescence quantum yield is also affected by quenching attributable to water structure and dye dimerization. 51 refs., 7 figs., 1 tab.

Isak, S.J.; Eyring, E.M. [Univ. of Utah, Salt Lake City, UT (United States)

1992-02-20

280

First crystal structure of a fungal high-redox potential dye-decolorizing peroxidase: substrate interaction sites and long-range electron transfer.  

PubMed

Dye-decolorizing peroxidases (DyPs) belong to the large group of heme peroxidases. They utilize hydrogen peroxide to catalyze oxidations of various organic compounds. AauDyPI from Auricularia auricula-judae (fungi) was crystallized, and its crystal structure was determined at 2.1 ? resolution. The mostly helical structure also shows a ?-sheet motif typical for DyPs and Cld (chlorite dismutase)-related structures and includes the complete polypeptide chain. At the distal side of the heme molecule, a flexible aspartate residue (Asp-168) plays a key role in catalysis. It guides incoming hydrogen peroxide toward the heme iron and mediates proton rearrangement in the process of Compound I formation. Afterward, its side chain changes its conformation, now pointing toward the protein backbone. We propose an extended functionality of Asp-168, which acts like a gatekeeper by altering the width of the heme cavity access channel. Chemical modifications of potentially redox-active amino acids show that a tyrosine is involved in substrate interaction. Using spin-trapping experiments, a transient radical on the surface-exposed Tyr-337 was identified as the oxidation site for bulky substrates. A possible long-range electron transfer pathway from the surface of the enzyme to the redox cofactor (heme) is discussed. PMID:23235158

Strittmatter, Eric; Liers, Christiane; Ullrich, René; Wachter, Sabrina; Hofrichter, Martin; Plattner, Dietmar A; Piontek, Klaus

2013-02-01

281

In situ investigation of dye adsorption on TiO2 films using a quartz crystal microbalance with a dissipation technique.  

PubMed

Dye adsorption plays a crucial role in dye-sensitized solar cells. Herein, we demonstrate an in situ liquid-phase analytical technique to quantify in real time adsorption of dye and coadsorbates on flat and mesoporous TiO(2) films. For the first time, a molar ratio of co-adsorbed Y123 and chenodeoxycholic acid has been measured. PMID:22641293

Harms, Hauke A; Tétreault, Nicolas; Gusak, Viktoria; Kasemo, Bengt; Grätzel, Michael

2012-07-01

282

Fully resonant four-wave mixing spectroscopy of pentacene and dye molecules in condensed phases  

SciTech Connect

Four-wave mixing spectroscopy (FWM) including coherent antistokes Raman spectroscopy (CARS) and coherent stokes Raman spectroscopy (CSRS) have been studied for pentacene doped in naphthalene crystals at low temperatures (4.5 to 35 K) in order to investigate nonlinear optical behavior of the third-order nonlinear susceptibility, X/sup (3)/. Further, its application to study of cresyl violet perchlorate embedded in polyacrylic acid and in polyvinyl carbazole has been examined. The theoretical basis for line narrowing has been established for fully resonant four wave mixing for a four-level system. A careful line-narrowing study for the pentacene 755 cm/sup -1/ resonance in naphthalene illustrates that line narrowing is operative. Temperature dependent studies indicate that the excited state population mechanism for negative detuning involves phonon hotband absorption. Power broadening data are discussed in terms of dynamic Stark shifts resulting from the site inhomogeneous line broadening of vibronic transitions. Cresyl violet perchlorate in polyacrylic acid shows that the CARS intensity of the excited state resonance at 585 cm/sup -1/ depends on the location of the omega/sub 1/-field within the severely inhomogeneously broadened absorption profile of the dye. It is argued that the linear electron-phonon interaction is an important mechanism for the intensity of the excited state resonance.

Chang, T.C.

1985-01-01

283

Hevea brasiliensis cell suspension peroxidase: purification, characterization and application for dye decolorization.  

PubMed

Peroxidases are oxidoreductase enzymes produced by most organisms. In this study, a peroxidase was purified from Hevea brasiliensis cell suspension by using anion exchange chromatography (DEAE-Sepharose), affinity chromatography (Con A-agarose) and preparative SDS-PAGE. The obtained enzyme appeared as a single band on SDS-PAGE with molecular mass of 70 kDa. Surprisingly, this purified peroxidase also had polyphenol oxidase activity. However, the biochemical characteristics were only studied in term of peroxidase because similar experiments in term of polyphenol oxidase have been reported in our pervious publication. The optimal pH of the purified peroxidase was 5.0 and its activity was retained at pH values between 5.0-10.0. The enzyme was heat stable over a wide range of temperatures (0-60°C), and less than 50% of its activity was lost at 70°C after incubation for 30 min. The enzyme was completely inhibited by ?-mercaptoethanol and strongly inhibited by NaN3; in addition, its properties indicated that it was a heme containing glycoprotein. This peroxidase could decolorize many dyes; aniline blue, bromocresol purple, brilliant green, crystal violet, fuchsin, malachite green, methyl green, methyl violet and water blue. The stability against high temperature and extreme pH supported that the enzyme could be a potential peroxidase source for special industrial applications. PMID:23402438

Chanwun, Thitikorn; Muhamad, Nisaporn; Chirapongsatonkul, Nion; Churngchow, Nunta

2013-01-01

284

Hevea brasiliensis cell suspension peroxidase: purification, characterization and application for dye decolorization  

PubMed Central

Peroxidases are oxidoreductase enzymes produced by most organisms. In this study, a peroxidase was purified from Hevea brasiliensis cell suspension by using anion exchange chromatography (DEAE-Sepharose), affinity chromatography (Con A-agarose) and preparative SDS-PAGE. The obtained enzyme appeared as a single band on SDS-PAGE with molecular mass of 70 kDa. Surprisingly, this purified peroxidase also had polyphenol oxidase activity. However, the biochemical characteristics were only studied in term of peroxidase because similar experiments in term of polyphenol oxidase have been reported in our pervious publication. The optimal pH of the purified peroxidase was 5.0 and its activity was retained at pH values between 5.0–10.0. The enzyme was heat stable over a wide range of temperatures (0–60°C), and less than 50% of its activity was lost at 70°C after incubation for 30 min. The enzyme was completely inhibited by ?-mercaptoethanol and strongly inhibited by NaN3; in addition, its properties indicated that it was a heme containing glycoprotein. This peroxidase could decolorize many dyes; aniline blue, bromocresol purple, brilliant green, crystal violet, fuchsin, malachite green, methyl green, methyl violet and water blue. The stability against high temperature and extreme pH supported that the enzyme could be a potential peroxidase source for special industrial applications.

2013-01-01

285

Regression analysis for the sorption isotherms of basic dyes on sugarcane dust  

Microsoft Academic Search

The sorption of three basic dyes, named basic violet 10, basic violet 1, and basic green 4, from aqueous solutions onto sugarcane dust was studied. The results revealed the potential of sugarcane dust, a waste material, to be a low-cost sorbent. Equilibrium isotherms were analyzed using the Langmuir, the Freundlich, and the three-parameter Redlich–Peterson isotherms. In order to determine the

Yuh-Shan Ho; Wen-Ta Chiu; Chung-Chi Wang

2005-01-01

286

Adsorption of methyl violet onto mesoporous MCM-48 from aqueous solution.  

PubMed

In this study, hexadecyltrimethyl ammonium bromide and triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) were used as co-templates and tetraethoxysilane was used as silica source to synthesize mesoporous MCM-48, which was employed to adsorb methyl violet dye from water. The prepared MCM-48, after calcination at 550 degrees C, was found to have a high surface area of 1072 m2/g and a pore volume of 1.08 cm3/g. The MCM-48 adsorption of methyl violet in aqueous solution was studied using UV-visible spectrophotometry. Experimental conditions, including initial pH of sample solution, initial concentration, MCM-48 amount, adsorption time and temperature, were also investigated. Results showed that the adsorption behavior could well be depicted by Langmuir equations and pseudo-second-order kinetic model. The maximum adsorption capacity of 193.82 mg/g was obtained at 20 degrees C. The values for thermodynamic parameters deltaG0, deltaS0 and deltaH0 were all negative, showing that the MCM-48 adsorption of methyl violet was spontaneous and exothermic. PMID:24738444

Gu, Xingxing; Xu, Hong; Luo, Lingling; Wu, Jun; Lin, Hongjun; Chen, Jianrong

2014-06-01

287

Effect of functionalization on the adsorption capacity of cellulose for the removal of methyl violet.  

PubMed

In this research paper a comparative study has been carried out for the removal of methyl violet dye using unfunctionalized and functionalized cellulose. The functionalization was achieved through esterification of cellulose with furan-2,5-dione. The functionalization of the cellulose was evidenced using BET, FT-IR, SEM and TGA. The adsorption isotherm data was fitted using different isotherm models like Langmuir, Freundlich, Temkin, Flory-Huggins and Dubinin-Kaganer-Radushkevich models and found to follow Langmuir and Temkin isotherm models with high value of correlation coefficients. Functionalized cellulose (106.38 mg g(-1)) showed higher dye removal capability than unfunctionalized cellulose (43.668 mg g(-1)). The kinetics of adsorption was investigated using pseudo first order, second order, Elovich, liquid film diffusion and intra-particle diffusion models. The mechanism of adsorption was found to follow pseudo second order rate equation. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous. PMID:24480254

Musyoka, Stephen Makali; Mittal, Hemant; Mishra, Shivani B; Ngila, Jane Catherine

2014-04-01

288

Action spectra of the photopotential generation for pigment and dye solutions in nematic liquid crystals located in the electrochemical cell  

Microsoft Academic Search

The method of measurements of the action spectra of photopotential generation using a modulated acting light beam was elaborated and applied to two systems: the solutions of stilbazolium merocyanines and to the mixture of chlorophyll a and luteine. Both types of samples were dissolved in nematic liquid crystal and located either between two semiconducting electrodes, or between a transparent gold

N. S. Naser; A. Planner; D. Fra?ckowiak

1998-01-01

289

The Swift Ultra-Violet\\/Optical Telescope  

Microsoft Academic Search

The Ultra-Violet\\/Optical Telescope (UVOT) is one of three instruments flying aboard the Swift Gamma-ray Observatory. It is designed to capture the early (?1 min) UV and optical photons from the afterglow of gamma-ray\\u000a bursts in the 170–600 nm band as well as long term observations of these afterglows. This is accomplished through the use\\u000a of UV and optical broadband filters

Peter W. A. Roming; Thomas E. Kennedy; Keith O. Mason; John A. Nousek; Lindy Ahr; Richard E. Bingham; Patrick S. Broos; Mary J. Carter; Barry K. Hancock; Howard E. Huckle; S. D. Hunsberger; Hajime Kawakami; Ronnie Killough; T. Scott Koch; Michael K. Mclelland; Kelly Smith; Philip J. Smith; Juan Carlos Soto; Patricia T. Boyd; Alice A. Breeveld; Stephen T. Holland; Mariya Ivanushkina; Michael S. Pryzby; Martin D. Still; Joseph Stock

2005-01-01

290

Colour Phenomena in Ultra-Violet Vision  

Microsoft Academic Search

THE note by N. I. Pinegin1 suggests a more detailed discussion of the relation between the threshold intensities for scotopic and photopic vision in the ultra-violet. The threshold ratio Tp\\/Ts is a measure of the intensity range, often misleadingly called `photochromatic interval', in which the visual impression is free from the specific colour sensation. This intensity range is a marked

E. E. Schneider

1945-01-01

291

Hair Dyes  

Microsoft Academic Search

\\u000a Contact dermatitis to hair dye ingredients have been known since human started dyeing with aromatic amines like p-phenylenediamine\\u000a (PPD). Hair dye allergy may cause severe clinical reactions, with edema of the face, eyelids, and scalp. More moderate reactions\\u000a such as erythema, suppuration, and ulceration, typically at the scalp margin, on the ears, and sometimes with evidence of\\u000a eczema where the

David Basketter; Jeanne Duus Johansen; John McFadden; Heidi Søsted

292

Ultra Violet Imaging Telescope (UVIT) on ASTROSAT  

NASA Astrophysics Data System (ADS)

The Ultra Violet Imaging Telescope on ASTROSAT Satellite mission is a suite of Far Ultra Violet (FUV: 130 - 180 nm), Near Ultra Violet (NUV: 200 - 300 nm) and Visible band (VIS: 320-550nm) imagers. ASTROSAT is the multi-wavelength mission of ISRO. UVIT will image the sky simultaneously in three channels with a field of view diameter of ~ 28 arcminutes and an angular resolution < 1.8". Two identical co-aligned telescopes (T1, T2) of Ritchey-Chretien configuration (Primary mirror of ~375 mm diameter) collect the celestial radiation and feed the detector systems via a selectable filter on a filter wheel mechanism; gratings are available in the filter wheels of FUV and NUV channels for slitless low-resolution spectroscopy. The photon-counting detector system for each of the 3 channels is generically identical. One of the telescopes images in the FUV channel, while the other images in NUV and VIS channels via a beamsplitter. Images from the VIS channel are principally used for measuring drift, used in construction of images on the ground by shift and add, and to reconstruct absolute aspect of the images. Adequate baffling has been provided for reducing the scattered background from the Sun, earth albedo and other bright objects. The one-time opening mechanical cover on each telescope also works as a Sun-shield after deployment. We will present the overall (mechanical, optical and electrical) design of the payload.

Kumar, Amit; Ghosh, S. K.; Hutchings, J.; Kamath, P. U.; Kathiravan, S.; Mahesh, P. K.; Murthy, J.; Nagbhushana, S.; Pati, A. K.; Rao, M. N.; Rao, N. K.; Sriram, S.; Tandon, S. N.

2012-09-01

293

Optically induced space-charge fields, dc voltage, and extraordinarily large nonlinearity in dye-doped nematic liquid crystals.  

PubMed

We have observed extraordinarily large optical nonlinearity in Methyl Red-doped nematic liquid-crystal film. Grating diffraction can be generated with an optical intensity as low as 40 microW/cm(2) , and a refractive-index change coefficient of more than 6 cm(2)/ W is obtained. The effect is attributed to formation of an optically induced dc space-charge field and to the resulting reorientation of the highly birefringent nematic director axis. PMID:18084476

Khoo, I C; Slussarenko, S; Guenther, B D; Shih, M Y; Chen, P; Wood, W V

1998-02-15

294

Fluorescence of a dye-doped cholesteric liquid crystal film in the region of the stop band: theory and experiment  

Microsoft Academic Search

:   Due to the sinusoidal modulation of the dielectric properties along the helical axis, cholesteric liquid crystals exhibit\\u000a a photonic stop band for circularly polarized light, which strongly affects the emission of fluorescent guest molecules. In\\u000a this paper, we discuss the resulting changes in the emission spectrum. In an analytical treatment, we first derive the photonic\\u000a densities of states of

J. Schmidtke; W. Stille

2003-01-01

295

Development of dye-sensitized solar cells composed of liquid crystal embedded, electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers as polymer gel electrolytes.  

PubMed

In order to overcome the problems associated with the use of liquid electrolytes in dye-sensitized solar cells (DSSCs), a new system composed of liquid crystal embedded, polymer electrolytes has been developed. For this purpose, three types of DSSCs have been fabricated. The cells contain electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVdF-co-HFP) polymer gel electrolyte, with and without doping with the liquid crystal E7 and with a liquid electrolyte. The morphologies of the newly prepared DSSCs were explored using field emission scanning electron microscopy (FE-SEM). Analysis of the FE-SEM images indicate that the DSSC composed of E7 embedded on e-PVdF-co-HFP polymer gel electrolyte has a greatly regular morphology with an average diameter. The ionic conductivity of E7 embedded on e-PVdF-co-HFP polymer gel electrolyte was found to be 2.9 × 10(-3) S/cm at room temperature, a value that is 37% higher than that of e-PVdF-co-HFP polymer gel electrolyte. The DCCS containing the E7 embedded, e-PVdF-co-HFP polymer gel electrolyte was observed to possess a much higher power conversion efficiency (PCE = 6.82%) than that of an e-PVdF-co-HFP nanofiber (6.35%). In addition, DSSCs parameters of the E7 embedded, e-PVdF-co-HFP polymer gel electrolyte (V(oc) = 0.72 V, J(sc) = 14.62 mA/cm(2), FF = 64.8%, and PCE = 6.82% at 1 sun intensity) are comparable to those of a liquid electrolyte (V(oc) = 0.75 V, J(sc) = 14.71 mA/cm(2), FF = 64.9%, and PCE = 7.17%, both at a 1 sun intensity). PMID:22422008

Ahn, Sung Kwang; Ban, Taewon; Sakthivel, P; Lee, Jae Wook; Gal, Yeong-Soon; Lee, Jin-Kook; Kim, Mi-Ra; Jin, Sung-Ho

2012-04-01

296

Synthesis and characterization of bent-shaped azobenzene monomers: Guest-host effects in liquid crystals with azo dyes for optical image storage devices  

NASA Astrophysics Data System (ADS)

Six novel bent-shaped monomers were synthesized such as substituted/or non-substituted 1,3-phenylene bis-{4-[(4-allyloxy)phenylazo]benzoate} ( 4a- c) and substituted/or non-substituted 1,3-phenylene bis-{4-[3-(4-allyloxy-3-fluoro)phenylazo]benzoate} ( 4d- f) in which azobenzene moiety in the periphery and substituted/or non-substituted resorcinol as central unit with polymeriable double bonds are linked at both ends of all the molecules. The mesophase behavior was investigated using polarizing optical microscopy, DSC and XRD measurements. Four members of the family show an intercalated smectic (Sm intercal) phase and two were crystalline in nature. The trans-form of azo compounds ( 4a- f) showed a strong band in the UV region (355-366 nm), which was attributed to the ?-? ? transition, and a weak band in the visible region at 455-465 nm due to the n-? ? transition. When one of the azo dye ( 4d) is mixed with liquid crystal as a guest, showed greater increase in thermal back relaxation time which is useful for creation of optical image storage devices.

Lutfor, M. R.; Hegde, G.; Kumar, S.; Tschierske, C.; Chigrinov, V. G.

2009-11-01

297

Dye lasers  

SciTech Connect

This patent describes a dye laser. It consists of a composite composition of an inorganic oxide glass monolith with a microporous structure containing an incorporated solution comprising a solvent component and a lasable dye component. Wherein the glass monolith has sealed outer surfaces.

Kuder, J.E.; McGinnis, J.L.; Goldberg, H.A.; Hart, T.R.; Che, T.M.

1989-10-31

298

A review on applicability of naturally available adsorbents for the removal of hazardous dyes from aqueous waste.  

PubMed

The effluent water of many industries, such as textiles, leather, paper, printing, cosmetics, etc., contains large amount of hazardous dyes. There is huge number of treatment processes as well as adsorbent which are available for the processing of this effluent water-containing dye content. The applicability of naturally available low cast and eco-friendly adsorbents, for the removal of hazardous dyes from aqueous waste by adsorption treatment, has been reviewed. In this review paper, we have provided a compiled list of low-cost, easily available, safe to handle, and easy-to-dispose-off adsorbents. These adsorbents have been classified into five different categories on the basis of their state of availability: (1) waste materials from agriculture and industry, (2) fruit waste, (3) plant waste, (4) natural inorganic materials, and (5) bioadsorbents. Some of the treated adsorbents have shown good adsorption capacities for methylene blue, congo red, crystal violet, rhodamine B, basic red, etc., but this adsorption process is highly pH dependent, and the pH of the medium plays an important role in the treatment process. Thus, in this review paper, we have made some efforts to discuss the role of pH in the treatment of wastewater. PMID:21387170

Sharma, Pankaj; Kaur, Harleen; Sharma, Monika; Sahore, Vishal

2011-12-01

299

Impedance spectroscopy and dielectric anisotropy-type analysis in dye-doped nematic liquid crystals having different preliminary orientations  

NASA Astrophysics Data System (ADS)

Reorientation tendencies of liquid crystal (LC) molecules are investigated for two different fundamental orientation configurations known as homogeneous (HG) and homeotropic (HT). Dielectric anisotropy properties of a HT sample and a HG one are investigated as a function of frequency. The dielectric anisotropy changes from the positive type to the negative type. The obtained results suggest that the samples exhibit dielectrically controlled positive dielectric anisotropy (p-type ? ?) with a critical frequency transition to negative dielectric anisotropy (n-type ? ?) behavior. The high-frequency relaxation process exhibits non-Debye-type behavior due to dipolar rotation around the long molecular axis. The orientation configurations (HG and HT) change the dielectric anisotropy properties of the LC in a favorable manner.

Okutan, Mustafa; Yakuphanoglu, Fahrettin; Eren San, S.; Koysal, O?uz

2005-11-01

300

Light-scattering determination of visco-elastic and electro-optic parameters of azo and anthraquinone dye-doped liquid crystal molecules and consistent neural network empirical physical formula construction for scattering intensities  

NASA Astrophysics Data System (ADS)

In this paper, we achieved two aims. Firstly, laser light-scattering intensities in methyl red (MR) azo and disperse red (DR) anthraquinone dye-doped nematic liquid crystal (NLC) molecules were measured versus scattering angle and applied bias voltage. The following three NLC molecular structure parameters were determined: the visco-elastic constant ratios K11/ K22 and K33/ K22 by data-regression and Freedericksz voltages from the graphs drawn. All these NLC parameters were found to be dependent on the kind of the dye used. As the second aim, by nonlinear universal function approximator layered feedforward neural network (LFNN), we constructed explicitform of empirical physical formulas (EPFs) for theoretically unknown nonlinear azo and anthraquinone dye-doped NLC scattering intensity functions. Excellent LFNN test set (i.e. yet-to-be measured experimental data) predictions prove that the constructed LFNN-EPFs estimate unknown intensity functions consistently. The LFNN-EPFs, too, confirmed the dependency on the kind of dye used. In conclusion, physical laws embedded in the scattering data can be consistently extracted by LFNN. One significant potential application in molecular nonlinear optics domain is that these LFNN-EPFs, by various mathematical tools such as differentiation, integration, and minimization, can be used to obtain further NLC scattering intensity knowledge related molecular structural parameters. Such knowledge in turn may prove useful in developing new optical materials.

Yildiz, Nihat; Polat, Ömer; San, Sait Eren; Kaya, Nihan

2011-04-01

301

Photosensitive and all-optically fast-controllable photonic bandgap device and laser in a dye-doped blue phase with a low-concentration azobenzene liquid crystal.  

PubMed

This work demonstrates the feasibility of a novel photosensitive and all-optically fast-controllable photonic bandgap (PBG) device based on a dye-doped blue phase (DDBP), embedded with a low-concentration azobenzene liquid crystal (azo-LC). PBG of the DDBP can be reversibly fast-tuned off and on with the successive illumination of a weak UV and green beams. UV irradiation can transform the trans azo-LCs into bend cis isomers, which can easily disturb LCs at the boundary between the double twisting cylinders (DTCs) and the disclinations, and, then, quickly destabilize BPI to become a BPIII-like texture with randomly-oriented DTCs. Doing so may quickly destroy the BP PBG structure. However, with the successive illumination of a green beam, the BPI PBG device can be fast-turned on, owing to the fast disappearance of the disturbance of the azo-LCs on the boundary LCs via the green-beam-induced cis?trans back isomerization. The response time and irradiated energy density for turning off (on) the BP PBG device under the UV (green) beam irradiation are only 120 ms (120 ms) and 0.764 mJ/cm2 (2.12 mJ/cm2), respectively, which are a thousand-fold reduction in photoswitching a traditional cholesteric LC (CLC) PBG device based on similar experimental conditions (i.e., materials used, azo-LC concentration (1 wt%), spectral position of PBG peak, sample thickness, and temperature difference for a working temperature lower than the clearing one). The BP PBG device can significantly contribute to efforts to develop a photosensitive and all-optically fast-controlling LC laser. PMID:24787807

Lin, Jia-De; Lin, Yu-Meng; Mo, Ting-Shan; Lee, Chia-Rong

2014-04-21

302

Fungal and enzymatic decolourisation of artificial textile dye baths.  

PubMed

A textile dye Reactive Black 5 was used in screening 25 fungal strains for their decolourising ability. The most promising strains were tested in a medium containing specific constituents of a dye bath in order to approach real application conditions. It was shown that the concentrations of the constituents had to be reduced to allow fungal growth. Decolourisation started in cultures of Geotrichum candidum but was not complete. Only Bjerkandera adusta was able to decolourise the black-blue colour through violet and red to pale yellow. After 17 days spectral absorption coefficients, alpha, at three wavelengths, 620, 525 and 436 nm almost reached the permitted values. A partly purified manganese peroxidase prepared from B. adusta was tested for decolourisation of several artificial dye baths. The constituents seemed not to be inhibitory to the enzyme and no dilution was necessary. Evaluation of decolourisation gave different results, depending on the method used. The most efficient decolourisation on a percentage basis was observed in the dye bath of the anthraquinone dye Reactive Blue 19, followed by the diazo dye Reactive Black 5. However, based on absorbance units, the largest reduction was achieved with the Reactive Black 5 and Acid Orange 7 dye baths. Comparing the alpha values after 120 h fungal and enzymatic treatments of Reactive Black 5 dye bath the enzyme showed about 1.5 times greater colour reduction than the fungus. Given the tolerance to the constituents and concentration of dye baths, the enzyme proved to be a promising tool for their treatment. PMID:16310823

Mohorcic, Martina; Teodorovic, Simona; Golob, Vera; Friedrich, Jozefa

2006-06-01

303

A study on the adsorption of some cationic dyes onto acrylamide\\/itaconic acid hydrogels  

Microsoft Academic Search

Acrylamide\\/itaconic acid (AAm\\/IA) hydrogels prepared by irradiating with ? radiation were used in experiments on the adsorption of some cationic dyes such as basic red 9 (BR 9), basic green 4 (BG 4), cresyl violet (CV), and basic blue 20 (BB 20). Adsorption of the cationic dyes onto AAm\\/IA hydrogels is studied by batch adsorption technique. In the experiments of

Erdener Karadag; Dursun Saraydin; Olgun Giiven

1996-01-01

304

Photofading of ballpoint dyes studied on paper by LDI and MALDI MS.  

PubMed

The determination of the age of an ink entry from a questioned document is often a major problem and a controversial issue in forensic sciences. Therefore, it is important to understand the aging process of the different components found in ink. The aim of this work is to characterize the degradation processes of methyl violet and ethyl violet, two typical ballpoint dyes by using laser desorption/ionization (LDI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), and to evaluate the possible application of the method to forensic examination of documents. The mass spectrometric methods were first tested and were found to be adequate for the purpose of this work. Moreover, it is possible to analyze the dye from a stroke directly from the paper (LDI-MS), so the sample preparation is minimized. The degradation of the dyes methyl violet and ethyl violet in strokes from a ballpoint pen was studied under laboratory conditions influenced by different factors such as light, wavelength of light, heat, and humidity. Then, strokes from the same ballpoint were aged naturally in the dark or under the influence of light over one year and then analyzed. The results show that the degradation of these dyes strongly depends on light fluence. Humidity also increases degradation, which can be explained by the basicity of the paper. The influence of heat on the degradation process was found to be rather weak. It was also observed that the dyes from the ink strokes did not show significant degradation after one year of storage in the dark. In conclusion, the storage conditions of a questioned document and the initial composition of the dyes in the ink have to be known for correct interpretation of the age of an ink entry. Measurements over longer periods of time are necessary to follow the degradation of dyes exempt from light exposure. LDI was found adequate and very useful for the analysis of ballpoint dyes directly from paper without further pretreatment. PMID:16443368

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

2006-03-01

305

Stabilisation of a heptamethine cyanine dye by rotaxane encapsulation.  

PubMed

The crystal structure of a cyanine dye rotaxane shows that the cyclodextrin is tightly threaded round the polymethine bridge of the dye; encapsulation dramatically increases the kinetic chemical stability of the radicals formed on oxidation and reduction of the dye, making it possible to observe the rotaxane radical dication by ESR and UV-vis-NIR spectroscopy. PMID:18566717

Yau, C M Simon; Pascu, Sofia I; Odom, Susan A; Warren, John E; Klotz, Eric J F; Frampton, Michael J; Williams, Charlotte C; Coropceanu, Veaceslav; Kuimova, Marina K; Phillips, David; Barlow, Stephen; Brédas, Jean-Luc; Marder, Seth R; Millar, Val; Anderson, Harry L

2008-07-01

306

Biosorption of Basic Violet 5BN and Basic Green by waste brewery’s yeast from single and multicomponent systems  

Microsoft Academic Search

Background and aim  The biosorption of Basic Violet 5BN (BV) and Basic Green (BG) by waste brewery’s yeast (WBY) from single and binary systems\\u000a was investigated.\\u000a \\u000a \\u000a \\u000a \\u000a Results and discussion  For the single system, the adsorption of both dyes is pH-dependent and the optimum value is 5.0. At a lower initial concentration,\\u000a the kinetic data agree well with both pseudo-first-order and pseudo-second-order models,

Yunhai Wu; Li Jiang; YaJun Wen; JianXin Zhou; Shixun Feng

307

Photoassisted Fenton mineralisation of Acid Violet 7 by heterogeneous Fe(III)–Al 2O 3 catalyst  

Microsoft Academic Search

Photoassisted Fenton mineralisation of an azo dye Acid Violet 7 was studied in detail using a Fe(III) loaded Al2O3 as a heterogeneous catalyst in the presence of H2O2 and UV-A light. The catalyst ferrioxalate–Al2O3 is more efficient than ferricnitrate–Al2O3. 35% Fe3+ loaded Al2O3 shows maximum efficiency in the degradation. The effects of reaction parameters such as catalyst loading, H2O2 concentration,

Inbasekaran Muthuvel; Meenakshisundaram Swaminathan

2007-01-01

308

Torsional dynamics of molecules on barrierless potentials in liquids. I. Temperature and wavelength dependent picosecond studies of triphenyl-methane dyes  

SciTech Connect

The nonradiative decay dynamics of crystal violet, and other triphenyl-methane dyes, dissolved in a variety of solvents, are studied as a function of temperature. A linear viscosity dependence of the excited state absorption decay time in n-alcohol solvents is found at several constant temperatures. The temperature dependence at constant viscosity is anomalously negative over the entire viscosity range (0.6 to 8.0 cP) of these experiments. Various possible mechanisms for the observed behavior are critically discussed. Two color excite-and-probe studies reveal ground state bleach recovery times which are independent of excitation wavelength but strongly dependent on probe wavelength. The faster decay on the red side of the ground state absorption is shown to be the result of stimulated emission rather than the influence of a second state.

Ben-Amotz, D.; Harris, C.B.

1987-05-01

309

Dyeing properties of natural dyes extracted from eucalyptus  

Microsoft Academic Search

A natural dye was extracted from Eucalyptus camaldulensis and was used to dye cotton by direct dyeing method at different dyeing conditions. Then, the fastness properties of dyeing with different dyeing techniques were compared.

S. Ali; N. Nisar; T. Hussain

2007-01-01

310

Tunable organic thin-film laser pumped by an inorganic violet diode laser  

NASA Astrophysics Data System (ADS)

We demonstrate an organic thin-film distributed feedback (DFB) laser pumped by an inorganic violet laser diode (?=406 nm). The active organic medium consists of a highly efficient, modified poly(9,9-dioctylfluorene) derivative containing 12% of statistical intrachain 6,6'-(2,2'-octyloxy-1,1'-binaphthalene) binaphthyl spacer groups. The polymer is doped with 4 wt % of the stilbene dye 1,4-bis(2-(4-(N,N-di(p-tolyl)amino)phenyl)vinylbenzene). This guest-host system features minimum lasing threshold energy densities below 1 ?J/cm2 for second order DFB resonator geometries and significant absorption (7.3×104 cm-1) at the wavelength of the pumping diode laser. The entire setup states an extremely compact and cost effective, laser source tunable between 496 and 516 nm.

Riedl, T.; Rabe, T.; Johannes, H.-H.; Kowalsky, W.; Wang, J.; Weimann, T.; Hinze, P.; Nehls, B.; Farrell, T.; Scherf, U.

2006-06-01

311

New violet 3,3'-bipyridyl pigment purified from deep-sea microorganism Shewanella violacea DSS12.  

PubMed

We have purified a new violet pigment derived from Shewanella violacea DSS12 to determine its chemical structure. The pigment colored blue in tetrahydrofuran (THF) or chloroform and showed a broad absorption spectrum from 500 to 700 nm. X-ray diffraction analysis of single crystals showed that the chemical structure of this pigment was 5,5'-didodecylamino-4,4'-dihydroxy-3,3'-diazodiphenoquinone-(2,2'), containing the same chromophore as an indigoidine known as microbial blue pigment. The violet color of this pigment was due to hypsochromic shift (blue shift) caused by the side-by-side orientation of this pigment molecule, revealed by X-ray structural analyses of a single crystal. PMID:17102923

Kobayashi, Hideki; Nogi, Yuichi; Horikoshi, Koki

2007-03-01

312

Extraction of catechol violet, chrome azurol S and eriochrome cyanine R with chloroform solutions of liquid anion-exchangers.  

PubMed

The extraction of Catechol Violet, Chrome Azurol S and Eriochrome Cyanine R with chloroform solutions of tri-n-octylamine (TOA), TOA hydrochloride and Aliquat 336 has been investigated. From the extraction isotherms, absorption spectra of the organic phases and dependence of the extraction coefficients on extractant concentration, it was found that the singly-charged anions HL(-) are extracted preferentially, but acidic groups other than sulphonate can also form ion-pairs with alkylammonium cations at higher pH values of the aqueous phase, and at high acidity these dyes can be extracted other than by an anion-exchange reaction. The three dyes (especially Eriochrome Cyanine R and Chrome Azurol S) were strongly extracted with the liquid anion-exchanger used and Aliquat 336 was a better extractant than TOA or TOA hydrochloride. The absorption spectra for the organic phases containing Chrome Azurol S and Eriochrome Cyanine R depended on the extractant used. PMID:18963620

Przeszlakowski, S; Wydra, H

1984-06-01

313

Comparison of historic Grübler dyes with modern counterparts using thin layer chromatography.  

PubMed

The aniline dye industry was created in 1856 when William Perkin prepared the dye, mauve, from coal tar. Following that discovery, several dye manufacturing businesses were formed in Western Europe, most successfully in Germany. It was to these companies that early investigators turned to obtain these new dyes for the developing field of biology. In 1880, Dr. Georg Grübler started a company in Germany to supply the needs of biologists. Grübler dyes developed a reputation for excellence. In the study reported here, 29 samples of 12 Grübler dyes were compared to modern counterparts using thin layer chromatography. The dyes studied were basic fuchsine, acid fuchsine, safranine, pyronine, aniline blue, ponceau, gentian violet, methylene blue, orange G, malachite green, and Sudan III and IV. I found that these early Grübler dyes closely resembled modern day counterparts; however, the use of synonyms was confusing and some of the fat stains were mislabeled by modern criteria. The chromatograms of some dyes exhibited smearing, probably representing multiple closely related dye species. The study of old dyes provides interesting comparisons with modern counterparts as the center of dye manufacturing is moving from Europe and the United States to Asia. PMID:18074269

Titford, M

2007-08-01

314

The efficacies of common dyes in primary isolation media for recovery of pathogenic fungi.  

PubMed

Dyes incorporated into a basal medium of brain heart infusion, Sabhi, tryptic soy, or yeast extract--pepton--glucose (YxPG) agar for selective isolation of fungi were investigated. Dilutions of 1:500, 1:750, 1:1,000, 1:5,000, and 1:10,000 of 33 common dyes were tested against 11 gram-positive and 16 gram-negative bacteria. In addition, these dyes were tested against Cryptococcus neoformans, Candida albicans, and the dimorphic phases of Histoplasma capsulatum and Blastomyces dermatitidis. Twenty-one of the dyes did not inhibit any of the organisms tested. Brilliant green, gentian violet, and malachite green (at three dilutions) inhibited all the organisms tested. Methyl red was found to be the best dye in selecting for fungi. Several dyes were also found to inhibit selectively C. neoformans or C. albicans and the dimorphic fungi H. capsulatum or B. dermatitidis. PMID:389033

Brilliande, T W; Hollick, G E; Larsh, H W

1979-11-01

315

Removal of methyl violet from aqueous solution by perlite  

Microsoft Academic Search

The use of perlite for the removal of methyl violet from aqueous solutions at different concentration, pH, and temperature has been investigated. Adsorption equilibrium is reached within 1 h. The capacity of perlite samples for the adsorption of methyl violet was found to increase with increasing pH and temperature and decrease with expansion and increasing acid-activation. The adsorption isotherms are described

Mehmet Do?an; Mahir Alkan

2003-01-01

316

Determining the degradation efficiency and mechanisms of ethyl violet using HPLC-PDA-ESI-MS and GC-MS  

PubMed Central

Background The discharge of wastewater that contains high concentrations of reactive dyes is a well-known problem associated with dyestuff activities. In recent years, semiconductor photocatalysis has become more and more attractive and important since it has a great potential to contribute to such environmental problems. One of the most important aspects of environmental photocatalysis is in the selection of semiconductor materials like ZnO and TiO2, which are close to being two of the ideal photocatalysts in several respects. For example, they are relatively inexpensive, and they provide photo-generated holes with high oxidizing power due to their wide band gap energy. In this work, nanostructural ZnO film on the Zn foil of the Alkaline-Manganese Dioxide-Zinc Cell was fabricated to degrade EV dye. The major innovation of this paper is to obtain the degradation mechanism of ethyl violet dyes resulting from the HPLC-PDA-ESI-MS analyses. Results The fabrication of ZnO nanostructures on zinc foils with a simple solution-based corrosion strategy and the synthesis, characterization, application, and implication of Zn would be reported in this study. Other objectives of this research are to identify the reaction intermediates and to understand the detailed degradation mechanism of EV dye, as model compound of triphenylmethane dye, with active Zn metal, by HPLC-ESI-MS and GC-MS. Conclusions ZnO nanostructure/Zn-foils had an excellent potential for future applications on the photocatalytic degradation of the organic dye in the environmental remediation. The intermediates of the degradation process were separated and characterized by the HPLC-PDA-ESI-MS and GC-MS, and twenty-six intermediates were characterized in this study. Based on the variation of the amount of intermediates, possible degradation pathways for the decolorization of dyes are also proposed and discussed.

2012-01-01

317

Metallophyte status of violets of the section Melanium.  

PubMed

Violets from metal-enriched soils have controversially been described as both heavy-metal accumulators and excluders in the literature. The present study solves the issue for violets of the section Melanium (zinc violets, Viola lutea ssp. calaminaria and V. lutea ssp. westfalica; hartsease or wild pansy, Viola tricolor; and mountain pansy, V. lutea). The aims were to determine the concentrations of heavy metals in the soil and in the roots and shoots of field-collected plants, to evaluate the potential impact of colonisation by arbuscular mycorrhizal fungi on heavy-metal concentrations in the plant tissues, and to quantitatively define the localisation of the elements in root cross-sections. When these violets grow in low-metal soils, higher concentrations of the heavy metals were found in the roots and shoots than in the soil, whereas the opposite was seen in samples from high-metal soils. Under all field conditions examined, the roots of all of these species were colonised by arbuscular mycorrhizal fungi. However, V. tricolor was marginally colonised when the concentrations of Zn and P were higher in the soil. Determination of the spatial distribution of the elements in root cross-sections of these violets indicates tissue-specific deposition of elements within the vascular tissue, the cortex, and the rhizodermis. These data indicate that violets of the section Melanium are heavy-metal excluders. PMID:23859423

Hermann, Bothe; Katarina, Vogel-Mikuš; Paula, Pongrac; Matevž, Likar; Neva, Stepic; Primož, Pelicon; Primož, Vavpeti?; Luka, Jeromel; Marjana, Regvar

2013-11-01

318

Adsorption characteristics of humic acid-immobilized amine modified polyacrylamide/bentonite composite for cationic dyes in aqueous solutions.  

PubMed

Humic acid-immobilized amine modified polyacrylamide/bentonite composite (HA-Am-PAA-B) was prepared and used as an adsorbent for the adsorption of cationic dyes (Malachite Green (MG), Methylene Blue (MB) and Crystal Violet (CV)) from aqueous solutions. The polyacrylamide/bentonite composite (PAA-B) was prepared by intercalative polymerization of acrylamide with Na-bentonite in the presence of N,N'-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. The surface characterizations of the adsorbent were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0-8.0. The capacity of HA-Am-PAA-B was found to decrease in the following order: MG > MB > CV. The kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. The experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using Sheindrof-Rebhun-Sheintuch (SRS) (multicomponent Freundlich type) equation. PMID:19862952

Anirudhan, T S; Suchithra, P S

2009-01-01

319

Toxicity of imine-iminium dyes and pigments: electron transfer, radicals, oxidative stress and other physiological effects.  

PubMed

Although conjugation is well known as an important contributor to color, there is scant recognition concerning involvement of imine and iminium functions in the physiological effects of this class of dyes and pigments. The group includes the dyes methylene blue, rhodamine, malachite green, fuchsin, crystal violet, auramine and cyanins, in addition to the pigments consisting of pyocyanine, phthalocyanine and pheophytin. The physiological effects consist of both toxicity and beneficial aspects. The unifying theme of electron transfer-reactive oxygen species-oxidative stress is used as the rationale in both cases. Toxicity is frequently prevented or alleviated by antioxidants. The apparent dichotomy of methylene blue action as both oxidant and antioxidant is rationalized based on similar previous cases. This mechanistic approach may have practical benefit. This review is important in conveying, for the first time, a unifying mechanism for toxicity based on electron transfer-reactive oxygen species-oxidative stress arising from imine-iminium. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24852913

Kovacic, Peter; Somanathan, Ratnasamy

2014-08-01

320

A rapid and simple method for simultaneous determination of triphenylmethane dye residues in rainbow trouts by liquid chromatography-tandem mass spectrometry.  

PubMed

A rapid and simple LC-MS/MS method was developed and optimized for screening and confirmation of triphenylmethane dyes including malachite green (MG), leucomalachite green (LMG), crystal violet (CV), leucocrystal violet (LCV) and brilliant green (BG) in fish muscle with skin. Leucocrystal violet D6 (LCV-D6) and leucomalachite green-D5 (LMG D5) was used as internal standards. Sample preparation is a simple procedure based on solid-liquid extraction with acetonitrile containing 1% acetic acid, followed by centrifugation and evaporation of the supernatant. The residue was dissolved in acetonitrile with 0.1% acetic acid and centrifuged prior to LC-MS/MS analysis. Chromatographic separation of analytes was performed on an Inertsil ODS-4 C18 column with ammonium acetate buffer in acetonitrile gradient. The mass detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI+). The developed method was validated according to the criteria set in Commission Decision 2002/657/EC. The decision limit (CC?) was 0.43, 0.24, 0.33, 0.28 and 0.17?gkg(-1) for MG, LMG, CV, LCV and BG respectively. The detection capability (CC?) values obtained were 0.56, 0.31, 0.43, 0.37 and 0.22?gkg(-1), respectively. The precision of the method, expressed as relative standard deviation (RSD) values for the within-day and inter-day laboratory reproducibility, for MG, LMG, CV, LCV and BG at the four levels of fortification (0.3, 0.5, 1, and 2?gkg(-1)), was less than 16 and 19% respectively. Accuracy of the method was confirmed by successful participation of a proficiency test organized by FAPAS. The method has been used for the analysis of 208 fish samples of which seven samples were found to be non-compliant containing low residues of LMG and LCV. PMID:24866565

Kaplan, Muammer; Olgun, Elmas O; Karaoglu, Oznur

2014-07-01

321

Effects of interaction of folic acid with uranium (VI) and basic triphenylmethane dyes on resonance Rayleigh scattering spectra and their analytical applications.  

PubMed

In pH 4.2-4.8 HAc-NaAc buffer solution, folic acid (FA) could react with uranium (VI) to form a 2:1 anionic chelate which further reacted with some basic triphenylmethane dyes (BTPMD) such as Ethyl Violet (EV), Methyl Violet (MV) and Crystal Violet (CV) to form 1:2 ion-association complexes. As a result, not only the absorption spectra were changed, but also the intensities of resonance Rayleigh scattering (RRS) were enhanced greatly and the new RRS spectra were observed. The maximum RRS wavelengths were located at 328 nm for EV system, 325 nm for MV system and 328 nm for CV system. The fading degree (DeltaA) and RRS intensities (DeltaI) of three systems were different. Under given conditions, the DeltaA and DeltaI were all directly proportional to the concentration of FA. The linear ranges and the detection limits of RRS methods were 0.0039-5.0 microg mL(-1) and 1.2 ng mL(-1) for EV system, 0.0073-4.0 microg mL(-1) and 2.2 ng mL(-1) for MV system, 0.014-3.5 microg mL(-1) and 4.7 ng mL(-1) for CV system. The RRS methods exhibited higher sensitivity, so they are more suitable for the determination of trace FA. The optimum conditions, the influencing factors and the effects of coexisting substances on the reaction were investigated. The method can be applied to the determination of FA in serum and urine samples with satisfactory results. The structure of the ternary ion-association complex and the reaction mechanism were discussed in this work. PMID:18374705

Xi, Cunxian; Liu, Zhongfang; Kong, Ling; Hu, Xiaoli; Liu, Shaopu

2008-04-14

322

Staphylococcus epidermidis biofilm quantification: Effect of different solvents and dyes.  

PubMed

Staphylococcus epidermidis biofilm formed in the presence of the solvents DMSO, ethanol or methanol was quantified using safranin or crystal violet staining protocols. We found that biofilm quantification was the most accurate when safranin protocol was applied. Moreover, both DMSO and ethanol stimulated biofilm formation. PMID:24726871

Wu, X; Santos, R R; Fink-Gremmels, J

2014-06-01

323

Dye laser amplifier  

DOEpatents

An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

Moses, E.I.

1992-12-01

324

Dye Sensitized Tandem Photovoltaic Cells  

SciTech Connect

This work provided a new way to look at photoelectrochemical cells and their performance. Although thought of as low efficiency, a the internal efficiency of a 9% global efficiency dye sensitized solar cell is approximately equal to an 18% efficient silicon cell when each is compared to their useful spectral range. Other work undertaken with this contract also reported the first growth oriented titania and perovskite columns on a transparent conducting oxide. Other work has shown than significant performance enhancement in the performance of dye sensitized solar cells can be obtained through the use of coupling inverse opal photonic crystals to the nanocrystalline dye sensitized solar cell. Lastly, a quick efficient method was developed to bond titanium foils to transparent conducting oxide substrates for anodization.

Barber, Greg D.

2009-12-21

325

crystal  

NASA Astrophysics Data System (ADS)

A Nd3+:Na2La4(WO4)7 crystal with dimensions of ? 17 × 30 mm3 was grown by the Czochralski method. The thermal expansion coefficients of Nd3+:Na2La4(WO4)7 crystal are 1.32 × 10-5 K-1 along c-axis and 1.23 × 10-5 K-1 along a-axis, respectively. The spectroscopic characteristics of Nd3+:Na2La4(WO4)7 crystal were investigated. The Judd-Ofelt theory was applied to calculate the spectral parameters. The absorption cross sections at 805 nm are 2.17 × 10-20 cm2 with a full width at half maximum (FWHM) of 15 nm for ?-polarization, and 2.29 × 10-20 cm2 with a FWHM of 14 nm for ?-polarization. The emission cross sections are 3.19 × 10-20 cm2 for ?-polarization and 2.67 × 10-20 cm2 for ?-polarization at 1,064 nm. The fluorescence quantum efficiency is 67 %. The quasi-cw laser of Nd3+:Na2La4(WO4)7 crystal was performed. The maximum output power is 80 mW. The slope efficiency is 7.12 %. The results suggest Nd3+:Na2La4(WO4)7 crystal as a promising laser crystal fit for laser diode pumping.

Yu, Yi; Huang, Yisheng; Zhang, Lizhen; Lin, Zhoubin; Sun, Shijia; Wang, Guofu

2014-07-01

326

Determination of the degradation products of selected sulfonated phenylazonaphthol dyes treated by white rot fungus Pleurotus ostreatus by capillary electrophoresis coupled with electrospray ionization ion trap mass spectrometry.  

PubMed

The removal of water-soluble sulphonated phenylazonaphthol dye effluents generated by textile industries is an important issue in wastewater treatment. Microbial treatment of environmental pollutants including dyes, with white rot fungi has received wide attention as a potential alternative for conventional methods in wastewater treatment. Three sulphonated phenylazonaphthol dyes with similar molecular structures Acid Orange 7, Acid Orange 8 and Mordant Violet 5 were selected and degraded by the white rot fungus Pleurotus ostreatus. Chemical instrumental analysis methods such as high-performance liquid chromatography (HPLC) and capillary electrophoresis combined with electrospray ionization mass spectrometry (CE-ESI-MS) were used to identify the degraded dyes. Mordant Violet 5 had two degradation pathways when degraded by P. ostreatus. The first degradation pathway for Mordant Violet 5 was for trans structure and the cis-Mordant Violet 5 followed the second pathway. Acid Orange 8 and Acid Orange 7 had the same degradation mechanism as the first degradation mechanism for Mordant Violet 5, that is cleavage of azo bond at the naphthalene ring side where benzenesulfonic acid and 1,2-naphthoquinone are formed. PMID:18778834

Lu, Yiping; Phillips, Dennis R; Lu, Lude; Hardin, Ian R

2008-10-24

327

Just Dyeing to Find Out.  

ERIC Educational Resources Information Center

Presents a multidisciplinary unit on natural dyes designed to take advantage of the natural curiosity of middle school students. Discusses history of dyes, natural dyes, preparation of dyes, and the dyeing process. (JRH)

Monhardt, Becky Meyer

1996-01-01

328

Hair Dye and Hair Relaxers  

MedlinePLUS

... Bad Reaction to Cosmetics? Tell FDA Cosmetics Tips Hair Dye and Hair Relaxers En Español Hair dye is ... hair relaxers. Hair Dyes Hair Relaxers Report Problems Hair Dyes There are different types of hair dyes used ...

329

crystal  

NASA Astrophysics Data System (ADS)

The polarized absorption, emission spectra and decay time measurements of Pr3+-doped CaYAlO4 single crystal have been performed at room temperature. Based on the Judd-Ofelt theory, the spectroscopic parameters , radiative transition probabilities, radiative lifetimes and branching ratios were obtained. The stimulated emission cross-section, fluorescence lifetimes and the quantum efficiency of the promising laser transition were also calculated and compared with other reported crystals. The results show that Pr3+:CaYAlO4 is a promising candidate for visible solid-state laser emission.

Lv, Shaozhen; Wang, Yan; Zhu, Zhaojie; You, Zhenyu; Li, Jianfu; Gao, Shufang; Wang, Hongyan; Tu, Chaoyang

2014-07-01

330

Starch/polyaniline nanocomposite for enhanced removal of reactive dyes from synthetic effluent.  

PubMed

Starch/polyaniline nanocomposite was synthesized by chemical oxidative polymerization of aniline and was subsequently analyzed for dye removal from aqueous solution. Batch experiment results showed that nanocomposite removed 99% of Reactive Black 5, 98% of Reactive Violet 4, and decolorized 87% of dye bath effluent. The Toth isotherm model better described single component equilibrium adsorption, whereas the modified Freundlich model showed satisfactory fit for dye bath. In kinetic modeling, single system followed pseudo-second-order and dye bath followed the modified pseudo-first-order model. Fourier transform infrared spectroscopy pattern of the nanocomposite showed the participation of aromatic, amino, hydroxyl, and carboxyl groups. The results indicate that starch/polyaniline nanocomposite can be used as an effective adsorbent for removal of dyes from textile effluents. PMID:22944400

Janaki, V; Vijayaraghavan, K; Oh, Byung-Taek; Lee, Kui-Jae; Muthuchelian, K; Ramasamy, A K; Kamala-Kannan, Seralathan

2012-11-01

331

Violet and blue light blocking intraocular lenses: photoprotection versus photoreception  

PubMed Central

Aim To analyse how intraocular lens (IOL) chromophores affect retinal photoprotection and the sensitivity of scotopic vision, melanopsin photoreception, and melatonin suppression. Methods Transmittance spectra of IOLs, high pass spectral filters, human crystalline lenses, and sunglasses are used with spectral data for acute ultraviolet (UV)?blue photic retinopathy (“blue light hazard” phototoxicity), aphakic scotopic luminous efficiency, melanopsin sensitivity, and melatonin suppression to compute the effect of spectral filters on retinal photoprotection, scotopic sensitivity, and circadian photoentrainment. Results Retinal photoprotection increases and photoreception decreases as high pass filters progressively attenuate additional short wavelength light. Violet blocking IOLs reduce retinal exposure to UV (200–400?nm) radiation and violet (400–440?nm) light. Blue blocking IOLs attenuate blue (440–500?nm) and shorter wavelength optical radiation. Blue blocking IOLs theoretically provide better photoprotection but worse photoreception than conventional UV only blocking IOLs. Violet blocking IOLs offer similar UV?blue photoprotection but better scotopic and melanopsin photoreception than blue blocking IOLs. Sunglasses provide roughly 50% more UV?blue photoprotection than either violet or blue blocking IOLs. Conclusions Action spectra for most retinal photosensitisers increase or peak in the violet part of the spectrum. Melanopsin, melatonin suppression, and rhodopsin sensitivities are all maximal in the blue part of the spectrum. Scotopic sensitivity and circadian photoentrainment decline with ageing. UV blocking IOLs provide older adults with the best possible rhodopsin and melanopsin sensitivity. Blue and violet blocking IOLs provide less photoprotection than middle aged crystalline lenses, which do not prevent age related macular degeneration (AMD). Thus, pseudophakes should wear sunglasses in bright environments if the unproved phototoxicity?AMD hypothesis is valid.

Mainster, M A

2006-01-01

332

Novel wafer stepper with violet LED light source  

NASA Astrophysics Data System (ADS)

Novel wafer stepper by using contact or proximity printing will be developed, using violet LED light source to replace Hg Arc. lamp or laser. Mirror, filter and condenser lens for Hg Arc. Lamp or laser and reduction lens for projection printing can be discarded. Reliability and manufacturing cost of wafer stepper can be improved. Exposure result by using IP3600 resist and wafer stepper with violet LED light source (wave-length 360nm to 410 nm) will be obtained. This novel wafer stepper can be used for 3DIC, MEMS and bio-chip lithography application by using thin and thick resist with sub-micron to 100 micron thickness.

Ting, Yung-Chiang; Shy, Shyi-Long

2014-03-01

333

Phase dislocations in a focused Gaussian beam induced via self-action in a dye-doped nematic liquid crystal cell  

NASA Astrophysics Data System (ADS)

We report the nucleation of wave front phase dislocations in a Gaussian beam with initially smooth wave front experienced the self-action in a nematic liquid crystal cell. It is shown experimentally that the structure of the aberrational rings appeared due to inducing of a nonlinear lens in liquid crystal bulk has more complicated character than mentioned earlier.

Pishnyak, O. P.; Reznikov, Yuri A.; Vasnetsov, Mikhail V.; Yaroshchuk, O. V.; Gorshkov, V. N.; Soskin, Marat S.

1999-11-01

334

Predicting azo dye toxicity  

Microsoft Academic Search

Literature regrading azo dye carcinogenicity was examined to establish, if possible, guidelines to predict the human health risks of new azo dyes. Three different mechanisms for azo dye carcinogenicity were identified, all involving metabolic activation to reactive electrophilic intermediates that covalently bind DNA. In the order of decreasing number of published references, these mechanisms are 1. Azo dyes that are

Mark A. Brown; Stephen C. De Vito

1993-01-01

335

Blue phases of cholesteric liquid crystals as thermotropic photonic crystals  

Microsoft Academic Search

The study of dye-doped low pitch cholesteric liquid crystals in their blue phases as an example of tunable ``weak'' photonic crystals is proposed and demonstrated. The presence of the blue phases in cholesterics can be tuned with temperature, and this allows for an easy in situ comparison of the emission and\\/or absorption of the dyes with or without an enwrapping

P. Etchegoin

2000-01-01

336

Grape stalks as substrate for white rot fungi, lignocellulolytic enzyme production and dye decolorization.  

PubMed

The aim of this work was to evaluate the potential of grape stalks, an agroindustrial waste, for growth and lignocellulolytic enzyme production via solid-state fermentation, using the following three white rot fungi: Trametes trogii, Stereum hirsutum and Coriolus antarcticus. The decolorization of several dyes by the above mentioned cultures was also investigated. Similar values of dry weight loss of the substrate were measured after 60 days (33-43 %). C. antarcticus produced the highest laccase and Mn-peroxidase activities (33.0 and 1.6 U/g dry solid). The maximum endoglucanase production was measured in S. hirsutum cultures (10.4 U/g), while the endoxylanase peak corresponded to T. trogii (14.6 U/g). The C. antarcticus/grape stalk system seems potentially competitive in bioremediation of textile processing effluents, attaining percentages of decolorization of 93, 86, 82, 82, 77, and 58% for indigo carmine, malachite green, azure B, remazol brilliant blue R, crystal violet and xylidine, respectively, in 5 h. PMID:22997770

Levin, Laura; Diorio, Luis; Grassi, Emanuel; Forchiassin, Flavia

2012-01-01

337

The mechanism of inhibition of initiation of protein synthesis in reticulocyte lysates by pyrocatechol violet.  

PubMed

1. Pyrocatechol violet inhibits the initiation of protein synthesis in reticulocyte lysates. It prevents the formation of 80-S initiation complexes by inhibiting the binding of mRNA to 40-S initiation complexes. 2. Pyrocatechol violet inhibits the hydrolysis of methionyl-tRNAmetf by reticulocyte lysates or reticulocyte cell sap. 3. Concentrations of pyrocatechol violet sufficient to inhibit initiation have little effect on amino acid activation. Higher concentrations of pyrocatechol violet were strongly inhibitory. PMID:938675

Margulies, L J; Kay, J E

1976-06-18

338

Electrochemical Studies of the Tin(IV)-Pyrocatechol Violet System.  

National Technical Information Service (NTIS)

In an effort to develop simpler methods for the analysis of natural waters for toxic organotin compounds, we have studied the electrochemical properties of pyrocatechol violet (PCV) and the complex formed by this reagent with tin(IV) Sn(IV).

D. A. Fine

1987-01-01

339

MODIFICATION AND CHARACTERIZATION OF DRY MATERIAL FEEDER FOR DELIVERY OF RED AND VIOLET DYE MIXTURES  

EPA Science Inventory

Uniform delivery of dry material for stable concentrations of aerosols in inhalation exposure chambers is essential in inhalation experiments. his paper characterizes an AccuRate dry material feeder with modifications, for different helix sizes, actuation rates, nozzle types and ...

340

Dye-sensitized Photoreactivation of X-ray Damage in Diploid Yeast  

Microsoft Academic Search

IN an investigation of the binding of aminoacridine dyes to deoxyribonucleic acid in living cells we have shown that the nucleic acid fluorochrome, acridine orange (3,6,-bis-dimethylaminoacridine), sensitizes both haploid and diploid yeast (Saccharomyces cerevisiae) to visible light1. The significance of the survival curves obtained for this acridine orange-sensitized photo-inactivation was further examined by experiments involving additivity of X-rays, ultra-violet and

David Freifelder; Robert B. Uretz

1960-01-01

341

Biodegradation of leuco derivatives of triphenylmethane dyes by Sphingomonas sp. CM9  

Microsoft Academic Search

A leuco derivatives of triphenylmethane dyes degrading bacterium, strain CM9, was isolated from an aquafarm field. Based on\\u000a morphology, physiologic tests, 16S rDNA sequence, and phylogenetic characteristics, it was identified as Sphingomonas sp. This strain was capable of degrading leucomalachite green (LMG), leucocrystal violet and leucobasic fuchsin completely.\\u000a The relationship between bacterium growth and LMG degradation suggested that strain CM9

Jun Wu; Liguan Li; Hongwei Du; Lijuan Jiang; Qiong Zhang; Zhongbo Wei; Xiaolin Wang; Lin Xiao; Liuyan Yang

2011-01-01

342

Study of excitation transfer in laser dye mixtures by direct measurement of fluorescence lifetime  

NASA Technical Reports Server (NTRS)

By directly measuring the donor fluorescence lifetime as a function of acceptor concentration in the laser dye mixture Rhodamine 6G-Cresyl violet, we found that the Stern-Volmer relation is obeyed, from which the rate of excitation transfer is determined. The experimental results indicate that the dominant mechanism responsible for the efficient excitation transfer is that of resonance transfer due to long range dipole-dipole interaction.

Lin, C.; Dienes, A.

1973-01-01

343

Directly hydrothermal growth of single crystal Nb3O7(OH) nanorod film for high performance dye-sensitized solar cells.  

PubMed

Hydrothermal growth of high crystallinity Nb(3) O(7) (OH) single crystal nanorod film onto FTO substrate is directly used as the photoanode for DSSCs without calcination. The resultant DSSCs possess an impressive overall efficiency of 6.77%, the highest among all reported DSSCs assembled by niobium oxide-based photoanodes. PMID:22354561

Zhang, Haimin; Wang, Yun; Yang, Dongjiang; Li, Yibing; Liu, Hongwei; Liu, Porun; Wood, Barry J; Zhao, Huijun

2012-03-22

344

New active media based on bifluorophormic compounds for dye lasers  

NASA Astrophysics Data System (ADS)

The photophysical properties (photostability, spectral-luminescent and generation properties) of eight new organic compounds have been studied, in which the molecular composition of two flurophores -- 1,3,5-triphenylpyrazoline and 2,5-diphenylzoxazole-1,3 (or 2,5- diphenyloxazole-1,3,4) -- were included. The effect of the structure of the investigated molecules and the polar properties of solvents on the spectral position of absorption and fluorescence bands was analyzed. The dyes have been found to have a fluorescence quantum efficiency (gamma) between 0.40 and 0.82 in these solvents. The dye laser performance using these dyes has also been investigated using the same solvents under nitrogen-laser pumping to compare them with the commercially available standard dye POPOP, which generates radiation in the violet spectrum region and allows the extension of the range of the active media used in liquid lasers in this spectrum region. A tuning range of nearly 60 nm was obtained in the blue region with efficiency up to 85% in comparison to the standard dye POPOP.

Neyra Bueno, O. L.; Gruzinskiy, V. V.; Seniuk, M. A.; Afanasiady, L. S.

1996-02-01

345

Blue sensitizers for solar cells: Natural dyes from Calafate and Jaboticaba  

Microsoft Academic Search

Blue-violet anthocyanins from Jaboticaba (Myrtus cauliflora Mart) and Calafate (Berberies buxifolia Lam) were employed as TiO2 dye-sensitizers. Solar cells sensitized by Jaboticaba extracts achieved up to Jsc=9.0mAcm?2, Voc=0.59V, Pmax=1.9mWcm?2 and ff=0.54, while for Calafate sensitized cells the values determined were up to Jsc=6.2mAcm?2, Voc=0.47V, Pmax=1.1mWcm?2 and ff=0.36. Other natural dyes were evaluated without significant photocurrent, demonstrating that only selected extracts

André Sarto Polo; Neyde Yukie Murakami Iha

2006-01-01

346

Investigation on the interaction of the toxicant, gentian violet, with bovine hemoglobin.  

PubMed

Gentian violet (GV) is a well-known triarylmethane dye that is used in aquacultural, industrial and medicinal fields. But concerns in growing number have been paid to its potential health problems to human beings and its hazardous effects to environment. Herein, the toxic interaction of GV with bovine hemoglobin (BHb) was investigated by a series of spectroscopic methods and molecular modeling method. The fluorescence emission profile exhibited a remarkable quenching upon addition of GV to the buffered aqueous solution of BHb and the analysis of results revealed the dominant role of static quenching mechanism in GV-BHb interaction. The negative ?H and positive ?S values demonstrated that the electrostatic interactions mainly stabilized this toxicantprotein complex. Synchronous fluorescence, UV-Vis absorption and CD spectroscopic studies proved that the conformational change of BHb was induced by GV's combination. Molecular modeling studies exhibited the binding mode of GV-BHb complex and the detailed information of related driving forces. During the (1)H nuclear magnetic resonance spectra ((1)H NMR) study, the chemical shift perturbation and spin-lattice relaxation times of different protons were further used to investigate the interaction of GV with BHb and the results indicated that GV bound orientationally to BHb. PMID:23643798

Liu, Yan; Lin, Jingjing; Chen, Mingmao; Song, Ling

2013-08-01

347

Biodegradation of Basic Violet 3 by Candida krusei isolated from textile wastewater.  

PubMed

Basic Violet 3 (BV) belongs to the most important group of synthetic colorants and is used extensively in textile industries. It is considered as xenobiotic compound which is recalcitrant to biodegradation. As Candida krusei could not use BV as sole carbon source, experiments were conducted to study the effect of cosubstrates on decolorization of BV in semi synthetic medium using glucose, sucrose, lactose, maltose, yeast extract, peptone, urea and ammonium sulphate. Maximum decolorization (74%) was observed in media supplemented with sucrose. Use of sugarcane bagasse extract as sole nutrient source showed 100% decolorization of BV within 24 h under optimized condition. UV-visible, FTIR spectral analysis and HPLC analysis confirmed the biodegradation of BV. Six degradation products were isolated and identified. We propose the biodegradation pathway for BV which occurs via stepwise reduction and demethylation process to yield mono-, di-, tri-, tetra-, penta- and hexa-demethylated BV species which was degraded completely. The study of the enzymes responsible for decolorization showed the activities of lignin peroxidase, lacasse, tyrosinase, NADH-DCIP reductase, MG reductase and azoreductase in cells before and after decolorization. A significant increase in activities of NADH-DCIP reductase and laccase was observed in the cells after decolorization. The yeast C. krusei could show the ability to decolorize the textile dye BV using inexpensive source like sugarcane bagasse extract for decolorization. PMID:21479732

Deivasigamani, Charumathi; Das, Nilanjana

2011-11-01

348

Microencapsulated Fluorescent Dye Penetrant.  

National Technical Information Service (NTIS)

Microencapsulated fluorescent dye pentrant materials were evaluated for feasibility as a technique to detect cracks on metal surfaces when applied as a free flowing dry powder. Various flourescent dye solutions in addition to a commercial penetrant (Zyglo...

S. Allinikov

1979-01-01

349

Fluorescent dye binding peptides  

US Patent & Trademark Office Database

The present invention is directed to novel polypeptides, termed fluorettes, that bind with high avidity to fluorophore dyes. The peptides find use in a variety of methods and approaches involving fluorophore dyes.

2004-06-08

350

Direct measurement of Ar diffusion profiles in a gem-quality Madagascar K-feldspar using the ultra-violet laser ablation microprobe (UVLAMP)  

Microsoft Academic Search

Controversy surrounding the mechanisms and controls on argon diffusion in K-feldspar has led us to undertake direct diffusion measurements on a crystal with simple microtextures, over a range of temperatures. Measurements of argon diffusion profiles in a gem-quality iron-rich orthoclase heated in a cold seal apparatus, have been undertaken in situ using an ultra-violet laser ablation microprobe (UVLAMP) technique. The

J.-A. Wartho; S. P. Kelley; R. A. Brooker; M. R. Carroll; I. M. Villa; M. R. Lee

1999-01-01

351

crystals  

NASA Astrophysics Data System (ADS)

A novel combined interferometric-mask method for the formation of micro- and nanometric scale three-dimensional (3D) rotational symmetry quasi-crystalline refractive lattice structures in photorefractive materials is demonstrated experimentally. The method is based on micrometric scale spatial modulation of the light by amplitude mask in the radial directions and along the azimuthal angle and the use of counter-propagating beam geometry building up Gaussian standing wave, which defines the light modulation in the axial direction with half-wavelength periodicity. 3D intensity pattern can be represented as numerous mask-generated 2D quasi-periodic structures located in each anti-node of the standing wave. The formed 3D intensity distributions of the optical beams can be imparted into the photorefractive medium thus creating the micro- and sub-micrometric scale 3D refractive index volume lattices. The used optical scheme allows also the formation of 2D lattices by removing the back-reflecting mirror. 2D and 3D refractive lattices were recorded with the use of 532 nm laser beam and rotational symmetry mask in doped lithium niobate crystals and were tested by the probe beam far-field diffraction pattern imaging and direct observation by phase microscope. The formed rotational symmetry 3D refractive structures have the periods of 20-60 ?m in the radial directions, 60 ?m along the azimuthal angle and half-wavelength 266 nm in the axial direction.

Badalyan, A.; Hovsepyan, R.; Mantashyan, P.; Mekhitaryan, V.; Drampyan, R.

2014-07-01

352

Optofluidic dye lasers  

Microsoft Academic Search

Optofluidic dye lasers are microfabricated liquid dye lasers enabled by the microfluidics technology. The integration of dye\\u000a lasers with microfluidics not only facilitates the implementation of complete “lab-on-a-chip” systems, but also allows the\\u000a dynamical control of the laser properties which is not achievable with solid-state optical components. We review the recent\\u000a demonstrations of on-chip liquid dye lasers and some of

Zhenyu Li; Demetri Psaltis

2008-01-01

353

Pyrocatechol Violet in spectrophotometric and novel optical methods  

NASA Astrophysics Data System (ADS)

The published data on chemical and analytical characteristics and the use of binary and ternary Pyrocatechol Violet complexes in spectrophotometric and novel optical methods of analysis are generalised. New promising trends are considered including studies of chromaticity characteristics of complexes of this reagent with various metal ions formed in the presence of cationic surfactants on the surface of anion-exchange resins or neutral sorbents aimed at increasing the sensitivity of determinations and developing new, more efficient test scales and optical sensors.

Ivanov, Vadim M.; Kochelayeva, Galina A.

2006-03-01

354

Infrared Dye Laser Study.  

National Technical Information Service (NTIS)

Building on work done in Phase I of this study (See AD-748 863), research on near-infrared dye lasers continued along several lines. Eighteen more Kodak organic dyes were screened for laser action using a linear flash lamp for excitation. Six dyes lased b...

B. E. Plourde J. P. Webb

1973-01-01

355

THE FLUORESCENCE EFFICIENCIES OF THE CN VIOLET BANDS IN COMETS  

SciTech Connect

We have carried out calculations of the fluorescent equilibrium of the CN molecule in the solar radiation field as a function of heliocentric radial velocity and distance. The detailed rotational line intensities of the CN violet 0-0 band have been recalculated for radial velocities between -60 and +60 km s{sup -1} and at 10 distances in steps of {radical}2 from 0.25 to 5.7 AU. Comparisons with observed CN violet 0-0 band profiles yield reasonable agreement and remaining discrepancies are well understood. Based on the derived equilibrium rotational level populations of the ground state, 1-1 band rotational line intensities were also calculated. Total band fluorescence efficiencies for the violet {Delta}{nu} = 0 sequence are tabulated for the above range of distances and velocities, permitting the interpolation to any given comet's observational circumstances. These fluorescence efficiencies, L/N, or 'g-factors', needed to reduce CN emission band fluxes to CN abundances, are also accessible via a Web-based service. The values at any heliocentric distance vary by about a factor of two with varying velocities, but the specific structure of this variation with velocity changes dramatically with distance.

Schleicher, David G., E-mail: dgs@lowell.ed [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

2010-10-15

356

Tests and calibration on ultra violet imaging telescope (UVIT)  

NASA Astrophysics Data System (ADS)

Ultra Violet Imaging Telescope on ASTROSAT Satellite mission is a suite of Far Ultra Violet (FUV; 130 - 180 nm), Near Ultra Violet (NUV; 200 - 300 nm) and Visible band (VIS; 320-550nm) imagers. ASTROSAT is a first multi wavelength mission of INDIA. UVIT will image the selected regions of the sky simultaneously in three channels & observe young stars, galaxies, bright UV Sources. FOV in each of the 3 channels is ~ 28 arc-minute. Targeted angular resolution in the resulting UV images is better than 1.8 arc-second (better than 2.0 arc-second for the visible channel). Two identical co-aligned telescopes (T1, T2) of Ritchey-Chretien configuration (Primary mirror of ~375 mm diameter) collect the celestial radiation and feed to the detector system via a selectable filter on a filter wheel mechanism; gratings are available in the filter wheels of FUV and NUV channels for slit-less low resolution spectroscopy. The detector system for each of the 3 channels is generically identical. One telescope images in the FUV channel, and other images in NUV and VIS channels. One time open-able mechanical cover on each telescope also works as Sun-shield after deployment. We will present the optical tests and calibrations done on the two telescopes. Results on vibrations test and thermo-vacuum tests on the engineering model will also be presented.

Kumar, Amit; Ghosh, S. K.; Kamath, P. U.; Postma, Joe; Kathiravan, S.; Mahesh, P. K.; Nagbhushana, S.; Navalgund, K. H.; Rajkumar, N.; Rao, M. N.; Sarma, K. S.; Sriram, S.; Stalin, C. S.; Tandon, S. N.

2012-09-01

357

Evaluation of the performance of calix[8]arene derivatives as liquid phase extraction material for the removal of azo dyes.  

PubMed

This paper presents a study on the removal of azo dyes (Reactive Black 5, Trapaeolin 000, Methyl Orange and Direct Violet 51) with calix[n]arene derivatives from aqueous solution into the organic phase in order to explore the potential use of calixarenes as low-cost efficient extractants for wastewater dye removal. The carboxylic acid derivative of calix[8]arene shows highest affinity towards the azo dyes. The influence of NaCl (present in the solution) on extraction process was also studied. The extent of the dye removal increased with the addition of NaCl. The proposed extraction mechanism involves several kinds of interactions: electrostatic repulsion between carboxylic acid groups of calix[8]arenes and sulfonate groups of azo dyes, hydrogen bonding and formation of an inclusion complex due to three dimensional cavity type calix[n]arene molecules through host-guest interactions. PMID:18321641

Gungor, Omer; Yilmaz, Aydan; Memon, Shahabuddin; Yilmaz, Mustafa

2008-10-01

358

Using protein nanofibrils to remove azo dyes from aqueous solution by the coagulation process.  

PubMed

The ever-increasing applications of hazardous azo dyes as industrialized coloring agents have led to serious remediation challenges. In this study, proteinaceous nanofibrils were examined as coagulants for decolorization of azo dyes in aqueous solutions. The results provided some insight regarding the mechanism of dye removal. The strength of nanofibrils to remove dyes from solution was evaluated by remediation of acid red 88, Bismarck brown R, direct violet 51, reactive black 5, and Congo red. However, the efficiency of nanofibrils to coagulate with different dyes was variable (60-98%) and dependent on the structures of dyes and the physicochemical conditions of the solutions. Increasing the temperature or ionic strength declined the coagulation time and induced the rate of dye removal. Changing pH had contradictory effects on the dye removal efficiency which was more affected by the chemical structure of the dye rather than the change in stability of the coagulant. The efficiency of nanofibrils to remove dyes was more than that of charcoal, which is considered as one of the most common substances used for azo dye remediation which may be due to its well dispersion in the aqueous solutions, and slower rates of the coagulation than that of the adsorption process. Furthermore, cytotoxicity was not detected after treating cell cultures with the decolorized solutions. Accordingly, by integrating biological and biophysicochemical processes, proteinaceous nanofibrils can be promising candidates for treatment of colored wastewaters. Ease of production, proper and quick dispersion in water, without the production of dangerous dye by-products and derivatives, are some of the main advantages of nanofibrils. PMID:23999142

Morshedi, Dina; Mohammadi, Zeinab; Akbar Boojar, Masoud Mashhadi; Aliakbari, Farhang

2013-12-01

359

Polymeric dyes: useful nonabsorbable reference markers for intestinal perfusion studies in animals.  

PubMed

The properties of two polymeric dyes were examined to determine their suitability as nonabsorbable reference markers for intestinal perfusion studies. The first dye was a violet anthroquinone dye, R-478, named polyporphyre; the second was a blue anthroquinone dye, R-411, named polycyanine. The dyes could be determined spectrophotometrically over a concentration range of 0.03-5 microM (1-200 micrograms/mL) and had no appreciable osmotic effect. They were light stable and their absorption spectra did not change in solution over a pH range of 1-11. The dyes had a molecular weight of approximately 40,000 by gel permeation chromatography; they did not appear to have hydrophobic binding sites because they did not bind added dihydroxy bile acid or fatty acid anions. Determination of the dyes was not influenced by the presence of bilirubin when the latter was present at concentrations reported to occur in small intestinal content during digestion. The dyes did not interfere with an endpoint enzymatic determination of bile acids. The dyes caused little quenching of 3H- or 14C-radioactivity in a toluene-based liquid scintillation cocktail. Dyes were easily removed from aqueous solution by passage over a large-pore anion exchange column or by a BaCl2:ZnSO4 protein precipitation procedure. When tested in a rat jejunal perfusion model, changes in dye concentration evoked by hypotonic or hypertonic perfusates were identical to those of polyethylene glycol 4000, a commonly used reference marker. The dyes did not influence the rate of glucose absorption and did not bind to mucus.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:4009443

Dupas, J L; Moreau, M; Hofmann, A F

1985-03-01

360

Degradation of reactive, acid and basic textile dyes in the presence of ultrasound and rare earths [Lanthanum and Praseodymium].  

PubMed

Degradation of five textile dyes, namely Reactive Red 141 (RR 141), Reactive Blue 21 (RB 21), Acid Red 114 (AR 114), Acid Blue 113 (AB 113) and Basic Violet 16 (BV 16) in aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La(3+) and Pr(3+)). Kinetic analysis of the data showed a pseudo-first order degradation reaction for all the dyes. The rate constant (k), half life (t1/2) and the process efficiency (?) for various processes in degradation of dyes under different experimental conditions have been calculated. The influence of concentrations of dyes (16-40mg/L), pH (5, 7 and 9) and rare earth ion concentration (4, 12 and 20mg/L) on the degradation of dyes have also been studied. The degradation percentage increased with increasing rare earth amount and decreased with increasing concentration of dyes. Both horn and bath type sonicators were used at 20kHz and 250W for degradation. The sonochemical degradation rate of dyes in the presence of rare earths was related to the type of chromophoric groups in the dye molecule. Degradation sequence of dyes was further examined through LCMS and Raman spectroscopic techniques, which confirmed the sonochemical degradation of dyes to non-toxic end products. PMID:24491599

Srivastava, Pankaj; Goyal, Shikha; Patnala, Prem Kishore

2014-11-01

361

Studies of the adsorptive decoloration of aqueous solutions by MDFSD  

Microsoft Academic Search

The present study deals with the decoloration of water. Adsorptivity of moderate density fiberboard saw dust (MDFSD) for different dyes has been tested. Continuous as well as batch systems were used to evaluate the adsorptivity of three different dyes (crystal violet, methyl blue and brilliant green). Breakthrough times of the three dyes were compared. Crystal violet was chosen for more

Khaled Hartani; Khaled Alsousy; Hisham Aila

362

Laser ablation of dyes  

NASA Astrophysics Data System (ADS)

High density 50 ?s pulses of the UV dyes PPF, POPOP and BBO and of two dyes in the visible region, Xanthen N92 and Fluorol 7GA were generated by laser ablation. Dye powders were pressed with 7800 kp/cm 2 in round pellets which were ablated by exposure to KrF excimer laser radiation (248 nm) at a fluence of 100 mJ/cm 2. The ablation cloud was optically activated with a XeCl excimer laser. Its fluorescence spectrum was measured and was identified as a dye vapour fluorescence spectrum by comparison to conventional dye solution and dye vapour spectra. The dye cloud is not deflected in an electric field (10 6 V/m). By changing the delay time between the ablation laser and the focused activation laser, the velocity distribution of the ablated dye was measured. Its maximum is at 600 m/s for PPF. Knowing the thickness of the ablated dye layer per shot (300 Å) and the size of the ablation cloud (pictures of a video camera), one can estimate the maximum density of the dye in the gas pulse to be 10 -5 mol/ l in the range of concentration of lasing dyes. However, no lasing was observed up to now.

Späth, M.; Stuke, M.

1992-01-01

363

A DNA Crystal Designed to Contain Two Molecules per Asymmetric Unit  

SciTech Connect

We describe the self-assembly of a DNA crystal that contains two tensegrity triangle molecules per asymmetric unit. We have used X-ray crystallography to determine its crystal structure. In addition, we have demonstrated control over the colors of the crystals by attaching either Cy3 dye (pink) or Cy5 dye (blue-green) to the components of the crystal, yielding crystals of corresponding colors. Attaching the pair of dyes to the pair of molecules yields a purple crystal.

T Wang; R Sha; J Birktoft; J Zheng; C Mao; N Seeman

2011-12-31

364

The investigation of inclusion behavior of Solvent Violet 9 with 4-sulfonatocalix[n]arenes and its recognition to DNA  

NASA Astrophysics Data System (ADS)

The inclusion behavior of Solvent Violet 9 (SV9) with 4-sulfonatocalix[n]arenes (SCXn) (n = 4, 6, 8) was investigated at various pH values by ultraviolet-visible spectroscopy. SV9 is able to form an inclusion complex with calixarenes. Different absorption behaviors were observed for the dye with the various host calixarenes. The molecular binding abilities were affected by the configuration of the calixarene cavities and the solution pH. Various experimental conditions, including calixarenes concentrations, were investigated and the results suggested that the three calixarene were most suitable for inclusion of the dye at pH = 3.05. The formation constant could be calculated. The inclusion behavior of the complexes was studied in detail using nuclear magnetic resonance spectroscopy. Finally, the interactions of SV9 with Salmon testes DNA in SCXn supramolecular system were studied by UV-Vis absorption spectroscopy. The UV-Vis absorption show that the interaction of SV9 with DNA depends on the concentration ratio of SV9 to DNA and the pH values. The binding constants of inclusion complexes with DNA are calculated. It was observed that SCXn can affect the interactive mode of SV9 with DNA.

Chao, Jianbin; Wang, Hong fang; Zhang, Yongbin; Huo, Fangjun; Yin, Caixia

2013-02-01

365

Spectrophotometric determination of germanium with Catechol Violet and cetyltrimethylammonium bromide.  

PubMed

A ternary complex between germanium, Catechol Violet (CV) and cetyltrimethylanunoniuni bromide is proposed for the determination of germanium. The stoichiometric ratio Ge:CV is 1:2. Beer's law is obeyed from 0.1 to 1.0 ppm of Ge. The method is highly selective. Interference from Sn(IV), Fe(III), Bi(III), Cr(VI), Mo(VI), V(V) and Sb(III) in mg amounts is eliminated by extracting the germanium into carbon tetrachloride from 9M HC1 and then stripping into water before the photometric determination. PMID:18960953

Leong, C L

1971-08-01

366

Peruvian natural dye plants  

Microsoft Academic Search

The use of natural dyes to color textiles and other objects has a long history in Andean South America, but has for the most\\u000a part become a lost technology with the introduction of synthetic dyes. A literature and field survey to recover information\\u000a about the traditional use of dye plants in Peru, from pre-Hispanic to recent times, was accompanied by

Kay K. Antúnez de Mayolo

1989-01-01

367

Ultrasonic assisted dyeing. IV. Dyeing of cationised cotton with lac natural dye  

Microsoft Academic Search

The dyeing of cationised cotton fabrics with lac natural dye has been studied using both conventional and ultrasonic techniques. The effects of dye bath pH, salt concentration, ultrasonic power, dyeing time and temperature were studied and the resulting shades obtained by dyeing with ultrasonic and conventional techniques were compared. Colour strength values obtained were found to be higher with ultrasonic

M. M. Kamel; Reda M. El-Shishtawy; B. M. Youssef; H. Mashaly

2007-01-01

368

Dyeing Wool with Fungi  

NSDL National Science Digital Library

In this activity (p.23 of PDF), learners dye wool with fungi. Learners discover that natural chemicals in fungi can dye wool different colors. Note: Natural dyeing normally requires a color fixative such as alum. This is not necessary if you use an aluminum, tin, or copper pot as the metal in the pot will take part in the dyeing reaction. However, if you use a non-stick saucepan you should add a few copper coins to the mix. Safety note: Always wash your hands after touching fungi! Adult supervision recommended.

Assinder, Sue; Rutter, Gordon

2002-01-01

369

Chemical Stabilization of Laser Dyes.  

National Technical Information Service (NTIS)

Coumarin laser dyes upon excitation degrade to produce products which absorb at the lasing wavelength. This results in attenuation of dye laser output. Modes of degradation of coumarin dye lasers under both anaerobic and aerobic conditions were determined...

T. H. Koch

1984-01-01

370

Tunable light source with GaN-based violet laser diode  

NASA Astrophysics Data System (ADS)

GaN based violet Laser Diode has been applying for the industrial market with unique high potential characters. It has possibility Replacing Gas lasers, Dye Lasers, SHG lasers and Solid-state Lasers and more. Diode based laser extreme small and low costs at the high volume range. In addition GaN Laser has high quality with long lifetime and has possibility to cover the wide wavelength range as between 375 to 520nm. However, in general, diode based laser could only lase with Longitudinal Multi Mode. Therefore applicable application field should be limited and it was difficult to apply for the analysis. Recently, Single Longitudinal Mode laser with GaN diode has also be accomplished with external cavity by Nichia Corporation. External cavity laser achieved at least much higher than 20dB SMSR. The feature of installing laser is that Laser on the front facet with AR coating to avoid chip mode lasing. In general, external cavity laser has been required precision of mechanical assembly and Retention Capability. Nichia has gotten rid of the issue with Intelligence Cavity and YAG Laser welding assembly technique. This laser has also been installed unique feature that the longitudinal mode could be maintained to Single Mode lasing with installing internal functional sensors in the tunable laser.*1,*2 This tunable laser source could lock a particular wavelength optionally between 390 to 465nm wavelength range. As the results, researcher will have benefit own study and it will be generated new market with the laser in the near future.

Omori, Masaki; Mori, Naoki; Dejima, Norihiro

2013-03-01

371

21 CFR 500.29 - Gentian violet for use in animal feed.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Gentian violet for use in animal feed. 500.29 Section 500.29...HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS...500.29 Gentian violet for use in animal feed. The Food and Drug...

2013-04-01

372

Salinity Measurements and General Condition of Violet Marsh, Post Hurricane Katrina.  

National Technical Information Service (NTIS)

This technical note reports surface salinity measurements taken in Violet Marsh approximately 3-1/2 months after Hurricane Katrina, and compares them to measurements made in 1993-1994 as part of the Violet Siphon Project. This note also includes photo doc...

J. P. Lin B. A. Kleiss

2006-01-01

373

Optical and piezoelectric effects in cholesteric liquid crystals and gels  

Microsoft Academic Search

Optically stabilized reflectors are demonstrated in this dissertation. These systems consist of a cholesteric liquid crystal with temperature sensitive helix pitch, in combination with a light absorbing dye. Light entering the liquid crystal is absorbed by the dye, generating heat which raises the temperature of the liquid crystal. The resulting change in the pitch length of the cholesteric causes an

Ching-Chao Chang

1997-01-01

374

Oxazine laser dyes  

DOEpatents

New oxazine compounds useful as dye laser media in solution, are superiior to prior art materials. The oxazine dyes useful when pumped by the 578.2 nm copper line to operate in the 700-800 nm range are described by formula I ##STR1##

Hammond, Peter R. (Livermore, CA); Field, George F. (Danville, CA)

1992-01-01

375

[Berlin dye laser].  

PubMed

The conditions for an optimal ophthalmic coagulating system are derived from the absorption spectra of xanthophyll, melanin and hemoglobin. Coagulation is effected by a dye laser with two dyes. The continuously tunable range of 570 nm to 680 nm opens up new horizons in photocoagulation of the retina. PMID:6543236

Wollensak, J; Seiler, T

1984-12-01

376

Tie-Dye Chemistry  

NSDL National Science Digital Library

In their travels to the indigo dye pits of northern Nigeria, the authors were struck by the beauty, history, and chemistry of indigo dyeing. They returned from Nigeria eager to develop a laboratory exercise that would expose students to the science of ind

Cessna, Gretchen; Cessna, Stephen

2001-03-01

377

Infrared Dye Laser Study.  

National Technical Information Service (NTIS)

Near infrared laser action has been demonstrated for 9 Kodak organic dyes, using a linear flash lamp for excitation. The spectral region covered by these 9 dyes extends from 850 nm to at least 960 nm, with no tuning attempted so far. Output is in the kilo...

B. E. Plourde J. P. Webb

1972-01-01

378

Application of photoacoustic, photothermal and fluorescence spectroscopies in signal enhancement and the kinetics, chemistry and photophysics of several dyes  

SciTech Connect

Modified photoacoustic and photothermal spectroscopies are applied in analytical studies of liquid and solid systems. Quenching of benzophenone by potassium iodide is used to demonstrate application of time resolved photothermal spectroscopies in study of fast (submicrosecond) deexcitation processes. Inherently weak X-ray photoacoustic signals at a synchrotron are enhanced by the introduction of a volatile liquid into a gas-microphone photoacoustic cell. Traditionally, photoacoustic signals have been detected either by gas coupling with a microphone or with a piezoelectric detector. However, optically detected photoacoustic signals have been used in the determination of physical properties of a liquid sample system and are successfully applied to the study of deexcitation processes of a number of dye molecules. Photothermal beam deflection photoacoustic (PBDPA), fluorescence and absorbance measurements are utilized to study the chemistry and photophysics of cresyl violet in aqueous, aqueous micellar and methanolic solutions. A concentration dependence of the fluorescence quantum yield of cresyl violet is investigated. Aspects of chemistry and photophysics relating to potential use of several diazo dyes as photothermal sensitizing dyes in photodynamic therapy are explored experimentally and discussed. Photothermal beam deflection, fluorescence and absorbance measurements are again utilized. The dyes are found to have a number of interesting chemical and photophysical properties. They are also determined to be ideal photothermal sensitizing dye candidates.

Isak, S.J.

1992-06-01

379

Monolithic dye laser amplifier  

DOEpatents

A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

Kuklo, T.C.

1993-03-30

380

Monolithic dye laser amplifier  

DOEpatents

A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

Kuklo, Thomas C. (Ripon, CA)

1993-01-01

381

Gentian Violet Exhibits Activity against Biofilms Formed by Oral Candida Isolates Obtained from HIV-Infected Patients?  

PubMed Central

The effect of gentian violet against Candida albicans and non-Candida albicans biofilms formed on polymethylmethacrylate strips was evaluated using a dry weight assay and confocal laser scanning microscopy. The ability of gentian violet to inhibit Candida albicans germination was also assessed. Gentian violet activity against Candida biofilms was demonstrated by a reduction in dry weight, disruption of biofilm architecture, and reduced biofilm thickness. Additionally, gentian violet inhibited Candida germination in a concentration-dependent manner.

Traboulsi, Rana S.; Mukherjee, Pranab K.; Chandra, Jyotsna; Salata, Robert A.; Jurevic, Richard; Ghannoum, Mahmoud A.

2011-01-01

382

TEXTILE DYES AND DYEING EQUIPMENT: CLASSIFICATION, PROPERTIES, AND ENVIRONMENTAL ASPECTS  

EPA Science Inventory

The report gives results of a study of available information on textile dyeing equipment, dyeing procedures, and dye chemistry, to serve as background data for estimating the properties and evaluating the associated risks of new commercial dyestuffs. It reports properties of dyes...

383

EVOLUTION AND BIOGEOGRAPHY OF THE WOODY HAWAIIAN VIOLETS (VIOLA, VIOLACEAE): ARCTIC ORIGINS, HERBACEOUS ANCESTRY AND BIRD DISPERSAL  

Microsoft Academic Search

Specialists studying the genus Viola have consistently allied the Hawaiian violets comprising section Nosphinium—most of which are subshrubs or treelets—with putatively primitive subshrubs in certain South American violet groups. Hawaiian violets also possess inflorescences, a floral disposition otherwise found only in other genera of the Violaceae, thus strengthening the hypothesis of a very ancient origin for the Hawaiian species. A

Kenneth J. Sytsma

2000-01-01

384

Luminescence spectra of PbFCl single crystal under the excitation of synchrotron radiation VUV–UV  

Microsoft Academic Search

The luminescence spectra of PbFCl single crystal under the excitation of synchrotron radiation vacuum ultraviolet–ultra violet (VUV–UV) were investigated. The emission spectra of PbFCl single crystal show a broad violet band peaking at 400nm having decreasing intensity with the rising temperature being from 20 to 293K under the excitation of VUV–UV. A weak ultraviolet band peaking at 325nm, which can

B. Liu; Chaoshu Shi; Zeming Qi; Yibin Fu; Guobin Zhang; Jianming Chen; Dingzhong Shen

2005-01-01

385

Pulsed ultra-violet inactivation spectrum of Escherichia coli.  

PubMed

Inactivation of Escherichia coli is examined using ultra-violet (UV) radiation from a pulsed xenon flashlamp. The light from the discharge has a broadband emission spectrum extending from the UV to the infrared region with a rich UV content. The flashlamp provides high-energy UV output using a small number of short-duration pulses (30 micros). The flashlamp is used with a monochromator to investigate the wavelength sensitivity of E. coli to inactivation by the pulsed UV light. Using 8 nm wide pulses of UV radiation, the most efficient inactivation is found to occur at around 270 nm and no inactivation is observed above 300 nm. A pyroelectric detector allows the energy dose to be determined at each wavelength, and a peak value for E. coli population reduction of 0.43 log per mJ/cm(2) is measured at 270 nm. The results are compared with the published data available for continuous UV light sources. PMID:15993922

Wang, T; Macgregor, S J; Anderson, J G; Woolsey, G A

2005-08-01

386

Transient transfection of mammalian cells using a violet diode laser  

NASA Astrophysics Data System (ADS)

We demonstrate the first use of the violet diode laser for transient mammalian cell transfection. In contrast to previous studies, which showed the generation of stable cell lines over a few weeks, we develop a methodology to transiently transfect cells with an efficiency of up to ~40%. Chinese hamster ovary (CHO-K1) and human embryonic kidney (HEK293) cells are exposed to a tightly focused 405-nm laser in the presence of plasmid DNA encoding for a mitochondrial targeted red fluorescent protein. We report transfection efficiencies as a function of laser power and exposure time for our system. We also show, for the first time, that a continuous wave laser source can be successfully applied to selective gene silencing experiments using small interfering RNA. This work is a major step towards an inexpensive and portable phototransfection system.

Torres-Mapa, Maria Leilani; Angus, Liselotte; Ploschner, Martin; Dholakia, Kishan; Gunn-Moore, Frank J.

2010-07-01

387

Dye system for dye laser applications  

DOEpatents

A dye of the DCM family, [2-methyl-6-[2-(1,2,3,4-tetrahydro-1-methyl-6-quinolinyl)ethenyl]-4H-pyran -4-ylidene]-propanedinitrile, dissolved in 2-phenoxyethanol, is non-mutagenic, stable and efficient, particularly in a pumped continuous wave laser system.

Hammond, Peter R. (Livermore, CA)

1991-01-01

388

Development and validation of a fast monoclonal based disequilibrium enzyme-linked immunosorbent assay for the detection of triphenylmethane dyes and their metabolites in fish.  

PubMed

Malachite Green (MG), Crystal Violet (CV) and Brilliant Green (BG) are antibacterial, antifungal and antiparasitic agents that have been used for treatment and prevention of diseases in fish. These dyes are metabolized into reduced leuco forms (LMG, LCV, LBG) that can be present in fish muscles for a long period. Due to the carcinogenic properties they are banned for use in fish for human consumption in many countries including the European Union and the United States. HPLC and LC-MS techniques are generally used for the detection of these compounds and their metabolites in fish. This study presents the development of a fast enzyme-linked immunosorbent assay (ELISA) method as an alternative for screening purposes. A first monoclonal cell line producing antibodies to MG was generated using a hybridoma technique. The antibody had good cross-reactivates with related chromatic forms of triphenylmethane dyes such as CV, BG, Methyl Green, Methyl Violet and Victoria Blue R. The monoclonal antibody (mAb) was used to develop a fast (20 min) disequilibrium ELISA screening method for the detection of triphenylmethanes in fish. By introducing an oxidation step with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) during sample extraction the assay was also used to detect the presence of the reduced metabolites of triphenylmethanes. The detection capability of the assay was 1 ng g(-1) for MG, LMG, CV, LCV and BG which was below the minimum required performance limit (MRPL) for the detection method of total MG (sum of MG and LMG) set by the Commission Decision 2004/25/EC (2 ng g(-1)). The mean recoveries for fish samples spiked at 0.5 MRPL and MRPL levels with MG and LMG were between 74.9 and 117.0% and inter- and intra-assay coefficients of variation between 4.7 and 25.7%. The validated method allows the analysis of a batch of 20 samples in two to three hours. Additionally, this procedure is substantially faster than other ELISA methods developed for MG/LMG thus far. The stable and efficient monoclonal cell line obtained is an unlimited source of sensitive and specific antibody to MG and other triphenylmethanes. PMID:21645659

Oplatowska, Michalina; Connolly, Lisa; Stevenson, Paul; Stead, Sara; Elliott, Christopher T

2011-07-18

389

Characteristics of dye-sensitized solar cells using natural dye  

Microsoft Academic Search

Dye-sensitized solar cells are expected to be used for future clean energy. Recently, most of the researchers in this field use Ruthenium complex as dye in the dye-sensitized solar cells. However, Ruthenium is a rare metal, so the cost of the Ruthenium complex is very high. In this paper, various dye-sensitized solar cells have been fabricated using natural dye, such

Shoji Furukawa; Hiroshi Iino; Tomohisa Iwamoto; Koudai Kukita; Shoji Yamauchi

2009-01-01

390

Percutaneous penetration of hair dyes  

Microsoft Academic Search

Scalp penetration of 7 hair dyes (oxidative and direct) that occurs under conditions of hair dye usage was evaluated for both rhesus monkey and man using 14C labeled materials by quantifying their absorbtion via urine assays. Both species showed a remarkably similar pattern of dye penetration. The extent of scalp penetratoon is slightly higher for direct dyes but in neither

L. J. Wolfram; H. I. Maibach

1985-01-01

391

Three-dimensional graphene oxide nanostructure for fast and efficient water-soluble dye removal.  

PubMed

In this study, we demonstrated the potential of graphene nanomaterials as environmental pollutant adsorbents by utilizing the characteristics of ultralarge surface area and strong ?-? interaction on the surface. We generated a three-dimensional (3D) graphene oxide sponge (GO sponge) from a GO suspension through a simple centrifugal vacuum evaporation method, and used them to remove both the methylene blue (MB) and methyl violet (MV) dyes which are main contaminants from the dye manufacturing and textile finishing. The efficiency and speed of dye adsorption on a GO sponge was investigated under various parameters such as contact time, stirring speed, temperature, and pH. The adsorption process shows that 99.1% of MB and 98.8% of MV have been removed and the equilibrium status has been reached in 2 min. The 3D GO sponge displays adsorption capacity as high as 397 and 467 mg g(-1) for MB and MV dye, respectively, and the kinetic data reveal that the adsorption process of MB and MV dyes is well-matched with the pseudo second-order model. The MB and MV adsorption on the 3D GO sponge involved in endothermic chemical adsorption through the strong ?-? stacking and anion-cation interaction with the activation energy of 50.3 and 70.9 kJ mol(-1), respectively. The 3D GO sponge has demonstrated its high capability as an organic dye scavenger with high speed and efficiency. PMID:22206476

Liu, Fei; Chung, Soyi; Oh, Gahee; Seo, Tae Seok

2012-02-01

392

Chemical stabilization of laser dyes  

NASA Astrophysics Data System (ADS)

Coumarin laser dyes upon excitation degrade to produce products which absorb at the lasing wavelength. This results in attenuation of dye laser output through interference of stimulated emission. The roles of singlet oxygen and excitation intensity on dye degradation were explored. Singlet oxygen is formed but its reactions with the dye do not appear to be a major cause of dye laser output deterioration. High light intensity results in dye sensitized, solvent oligomerization to yield materials which interfere with dye stimulated emission. 1, 4-Diazabicyclo2,2,2octane (DABCO)inhibits this oligomerization.

Koch, Tad H.

1987-05-01

393

Color-sensitive photoconductivity of nanostructured ZnO/fast green dye hybrid films  

NASA Astrophysics Data System (ADS)

Nanostructured ZnO/dye hybrid films prepared by sol gel method have been investigated in conductivity and photoconductivity measurements in view of applications in dye-sensitized solar cells (DSSC). The absorption of ZnO film sensitized by Fast Green dye (FGF) has been studied by UV spectroscopy which indicates that after the dye is adsorbed on the ZnO electrode, its absorption spectra showed red-shift in the peak position compared to the absorbance spectra of dye in ethanol. The films, in which dye molecules are located within the ZnO crystals, are found to show higher sensitivity to illumination with visible light in photoconductivity measurements due to a high proportion of surface dye molecules are being excited by ?-electrons acting as sensitizers.

Rani, Mamta; Tripathi, S. K.

2013-06-01

394

Anthraquinone Dye Toxicological Profiles.  

National Technical Information Service (NTIS)

The Consumer Product Safety Commission conducted a review of anthraquinone dyes having consumer application for which toxicity data was available. Both natural and synthetic anthraquinones have been employed as colorants in food, drugs, cosmetics, hair dy...

1981-01-01

395

Radio-fluorogenic dosimetry with violet diode laser-induced fluorescence  

NASA Astrophysics Data System (ADS)

A set of experiments is described with radio-fluorogenic detectors and violet diode lasers. Radio-fluorogenic dosimetry is the measurement of absorbed dose by quantification of fluorescent products formed in response to ionizing radiation. Relative dosimetry was accomplished with 405nm violet diode laser-induced fluorescence (LIF) and digital imaging. Aqueous and gelatin-based solutions of radio-fluorogenic detectors were fabricated, irradiated with medical radiation devices, and pixel intensity values of digital images analyzed. The potential to use RFD to characterize spatial dose distributions with violet diode LIF is demonstrated.

Sandwall, Peter; Spitz, Henry; Elson, Howard; Lamba, Michael; Connick, William; Fenichel, Henry

2014-03-01

396

Synthesis and X-ray crystal structure of isomeric pyridine-based leuco-TAM dyes, 2,2-(2-(pyridinyl)propane-1,3-diylidene)bis(5-chloro-1,3,3-trimethyl indoline) derivatives and unusual stability of 4-pyridinyl compound  

NASA Astrophysics Data System (ADS)

The solid-state structures and unequivocal stereochemistries of isomeric pyridine-based leuco-triarylmethane (LTAM) dyes 2,2'-(2-(pyridin-4 or 3-yl)propane-1,3-diylidene)bis(5-chloro-1,3,3-trimethylindoline) derivatives were established by X-ray crystallography. Surprisingly, the EE isomer was formed for the 4-pyridinyl compound, whereas the 3-pyridinyl compound formed ZE isomers. In addition, the latter have a so-called three-bladed propeller conformation, whereas the former possess a Y-shaped conformation. These pyridine-based LTAM compounds stack to form a dimer, adopting either an orthorhombic, with Pcmn space group, or monoclinic crystal system with P21/n space group in the crystal unit cell.

Ma, So-Young; Keum, Sam-Rok

2013-09-01

397

Poly(acrylamide) functionalized chitosan: an efficient adsorbent for azo dyes from aqueous solutions.  

PubMed

In the present communication we report on the optimization of persulfate/ascorbic acid initiated synthesis of chitosan-graft-poly(acrylamide) (Ch-g-PAM) and its application in the removal of azo dyes. The optimum yield of the copolymer was obtained using 16 x 10(-2)M acrylamide, 3.0 x 10(-2)M ascorbic acid, 2.4 x 10(-3)M K(2)S(2)O(8) and 0.1g chitosan in 25 mL of 5% aqueous formic acid at 45+/-0.2 degrees C. Ch-g-PAM remained water insoluble even under highly acidic conditions and could efficiently remove Remazol violet and Procion yellow dyes from the aqueous solutions over a pH range of 3-8 in contrast to chitosan (Ch) which showed pH dependent adsorption. The adsorption data of the Ch-g-PAM and Ch for both the dyes were modeled by Langmuir and Freundlich isotherms where the data fitted better to Langmuir isotherms. To understand the adsorption behavior of Ch-g-PAM, adsorption of Remazol violet on to the copolymer was optimized and the kinetic and thermodynamic studies were carried out taking Ch as reference. Both Ch-g-PAM and Ch followed pseudo-second-order adsorption kinetics. The thermodynamic study revealed a positive heat of adsorption (Delta H degrees), a positive DeltaS degrees and a negative Delta G degrees, indicating spontaneous and endothermic nature of the adsorption of RV dye on to the Ch-g-PAM. The Ch-g-PAM was found to be very efficient in removing color from real industrial wastewater as well, though the interfering ions present in the wastewater slightly hindered its adsorption capacity. The data from regeneration efficiencies for ten cycles evidenced the high reusability of the copolymer in the treatment of waste water laden with even high concentrations of dye. PMID:19097701

Singh, Vandana; Sharma, Ajit Kumar; Sanghi, Rashmi

2009-07-15

398

Catalytic effect of supported metal ion complexes on the induced oxidative degradation of pyrocatechol violet by hydrogen peroxide.  

PubMed

Kinetics of the oxidative degradation of pyrocatechol violet dye (PCV) [2-[(3,4-dihydroxyphenyl)(3-hydroxy-4-oxocyclohexa-2,5-dien-1-ylidene) methyl]-benzenesulfonic acid] by H(2)O(2) catalyzed by supported transition metal complexes have been studied. The reaction was followed by conventional UV-vis spectrophotometer at lambda(max)=440 nm in a buffer solution at pH 5.1. The supports used were silica gel and cation exchange resins (Dowex-50W, 2 and 8% DVB), while the complexes were [Cu(amm)(4)](2+), [Cu(en)(2)](2+), [Cu(ma)(4)](2+), [Co(amm)(6)](2+), and [Ni(amm)(6)](2+) (amm=ammonia, en=ethylenediamine, and ma=methylamine). The reaction exhibited first-order kinetics with respect to [PCV] and [H(2)O(2)]. The reactivity of the catalysts is correlated with the redox potential of the metal ions, the type of support, and the amount of supported complexes. The rate of the reaction increases with increasing pH and the addition of NaCl. Addition of SDS and CTAB showed inhibiting effects. The reaction is enthalpy-controlled as confirmed from the isokinetic relationship. A reaction mechanism involved the generation of free radicals as an oxidant has been proposed. PMID:12804907

Gemeay, Ali H; Mansour, Ikhlas A; El-Sharkawy, Rehab G; Zaki, Ahmed B

2003-07-01

399

Pyrocatechol Violet Complexation at the Boehmite-Water Interface.  

PubMed

Acid/base reactions and pyrocatechol violet complexation at the boehmite-solution interface have been investigated in 0.10 M K(Cl) solution at 298.2 K in the range 5.0violet {PCV, 2-[(3,4-dihydroxyphenyl)(3-hydroxy-4-oxocyclohexa-2,5-diene-1-ylidene)methyl]benzenesulfonic acid}, H(4)L, was described by the formation of a single inner-sphere complex according to the reaction identical withAlOH+H(4)Lleft harpoon ovet right harpoon identical withAlL(3-)+3H(+)+H(2)O. Allowing for a charge distribution of this complex between the inner plane and beta-plane (-2, -1), a significant improvement of the fit was obtained. The adsorbed complex exhibited a dark blue color over the pH range 5-8.5, indicative of proton loss from the 1,2-dihydroxyl moiety. Furthermore, DRIFT spectra showed the bonding environment of PCV bound to the surface to exhibit similarities with corresponding catechol adsorption to different aluminium (hydr)oxides. These spectral features turned out to be very similar to soluble catechol complexes of Al(III). Thus, it is suggested that PCV forms a mononuclear chelating complex at the boehmite-water interface. The maximum surface coverage reached was ca. 33%, indicating that the high negative charge of the species may result in surface charge "saturation" rather than saturation of surface binding sites. Steric hindrances caused by the large size of PCV may also contribute to the low surface coverage. Copyright 2000 Academic Press. PMID:10985837

Simpson; Powell; Sjöberg

2000-09-15

400

A pigment-producing spoilage bacterium responsible for violet discoloration of refrigerated market milk and cream.  

PubMed

A psychrophilic strain of bacteria identified as Chromobacterium lividum was established as the causative agent of an outbreak of violet discoloration in refrigerated, pasteurized retail milk and cream. The organism was rod-shaped, gram-negative, and produced viscid colonies with abundant violet pigment on Tryptone glucose yeast extract agar. Growth was abundant at 4 C but none occurred at 37 C. Growth in milk was characterized by a dark violet ring at the surface after a few days, and the deep violet color gradually extended through the product in older cultures. Some proteolysis occurred. The pigment appeared to be similar to that of other known species of Chromobacterium and assisted in identification of the genus of the causative organism. The isolated strain of C. lividum was destroyed by exposure to 56 C for 5 min which suggested postpasteurization contamination as the source of the spoilage organism in commercial milk and cream. PMID:13749823

SEITZ, E W; ELLIKER, P R; SANDINE, W E

1961-07-01

401

Vacuum ultra-violet absorption spectra of various mono-substituted benzenes  

Microsoft Academic Search

The vacuum ultra-violet spectra of various mono-substituted benzenes were measured in the wavelength region of 1550 Å to 2200 Å in the vapour phase by a recording vacuum ultra-violet spectrophotometer. The compounds studied here are phenols (phenol, anisole, phenetole and thiophenol), halogenobenzenes (fluorobenzene, chlorobenzene, bromobenzene and iodobenzene), and toluene. It was found that four pi-->pi* transition bands appear in the

K. Kimura; S. Nagakura

1965-01-01

402

Males on guard: paternity defences in violet-green swallows and tree swallows  

Microsoft Academic Search

Paternity-defence behaviour in two congeners, violet-green swallows,Tachycineta thalassina, and tree swallows,T. bicolor, was compared to identify ecological factors that influence how males avoid being cuckolded. Measurements of the proportion of time that mates spent together, their following behaviour and the rate of within-pair copulations revealed that male violet-green swallows allocated more time to guarding mates than nests and copulated with

BARBARA A. BEASLEY

1996-01-01

403

The Molecular Evolution of Avian Ultraviolet and Violet-Sensitive Visual Pigments  

Microsoft Academic Search

The shortwave-sensitive SWS1 class of vertebrate visual pigments range in kmax from the violet (385-445 nm) to the ultraviolet (UV) (365-355 nm), with UV-sensitivity almost certainly ancestral. In birds, however, the UV-sensitive pigments present in a number of species have evolved secondarily from an avian violet-sensitive (VS) pigment. All avian VS pigments expressed in vitro to date encode Ser86 whereas

Livia S. Carvalho; Jill A. Cowing; Susan E. Wilkie; James K. Bowmaker; David M. Hunt

2007-01-01

404

Heavily doped ZnO nanobelts and their violet emission.  

PubMed

In-doped ZnO nanobelts have been synthesized by a thermal evaporation method with absence of catalysts. The morphology and microstructure of the doped ZnO nanobelts have been extensively investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The results show that the belts grow along the (1010) direction with the typical lengths in the range of several tens to several hundreds of micrometers, and the typical widths of the belts are several hundreds of nanometers. According to the XRD pattern of the sample, the most of belts are ZnO with heavy doping content and ternary Zinc Indium Oxide (such as Zn5In2O8, Zn4In2O7). The X-ray energy dispersive spectrometer (EDS) analysis demonstrates that the In content in the as-examined belt is as high as 27 at%. Notably, the photoluminescence spectrum reveals a novel violet emission peak (425 nm) in the as-synthesized product. PMID:21456160

Chen, Yiqing; Shao, Yan; Zhang, Xinhua; Jia, Chong; Su, Yong; Li, Qiang; Liu, Lizhu; Guo, Taibo

2011-02-01

405

Solid hosts for dye laser rods: Part 1, Criteria for choosing a host material  

SciTech Connect

This paper will attempt to provide selection criteria for polymers as hosts for flashlamp-pumped dye laser rods. The properties of transparent polymer materials are compared with typical inorganic crystal and glass hosts. 2 figs., 1 tab.

Erickson, G.F.

1987-01-01

406

Lasing Thresholds of Cholesteric Liquid Crystals Lasers  

Microsoft Academic Search

Cholesteric liquid crystals (CLCs) are one dimensional photonic band-gap materials. Due to distributed feedback, low threshold mirrorless lasing can occur in dye-doped and pure CLCs. In order to optimize the lasing conditions, we have studied the dependence of the lasing threshold on dye concentration and sample thickness. In particular, we have studied dye concentrations in the range of 0.1–3.0 wt%, and

W. Cao; P. Palffy-Muhoray; B. Taheri; A. Marino; G. Abbate

2005-01-01

407

Lasing Thresholds of Cholesteric Liquid Crystals Lasers  

Microsoft Academic Search

Cholesteric liquid crystals (CLCs) are one dimensional photonic band-gap materials. Due to distributed feedback, low threshold mirrorless lasing can occur in dye-doped and pure CLCs. In order to optimize the lasing conditions, we have studied the dependence of the lasing threshold on dye concentration and sample thickness. In particular, we have studied dye concentrations in the range of 0.1-3.0wt%, and

W. Cao; G. Abbate; P. Palffy-Muhoray; B. Taheri

2004-01-01

408

Identification of methyl violet 2B as a novel blocker of focal adhesion kinase signaling pathway in cancer cells  

SciTech Connect

Highlights: •FAK signaling cascade in cancer cells is profoundly inhibited by methyl violet 2B. •Methyl violet 2B identified by virtual screening is a novel allosteric FAK inhibitor. •Methyl violet 2B possesses extremely high kinase selectivity. •Methyl violet 2B suppresses strongly the proliferation of cancer cells. •Methyl violet 2B inhibits focal adhesion, invasion and migration of cancer cells. -- Abstract: The focal adhesion kinase (FAK) signaling cascade in cancer cells was profoundly inhibited by methyl violet 2B identified with the structure-based virtual screening. Methyl violet 2B was shown to be a non-competitive inhibitor of full-length FAK enzyme vs. ATP. It turned out that methyl violet 2B possesses extremely high kinase selectivity in biochemical kinase profiling using a large panel of kinases. Anti-proliferative activity measurement against several different cancer cells and Western blot analysis showed that this substance is capable of suppressing significantly the proliferation of cancer cells and is able to strongly block FAK/AKT/MAPK signaling pathways in a dose dependent manner at low nanomolar concentration. Especially, phosphorylation of Tyr925-FAK that is required for full activation of FAK was nearly completely suppressed even with 1 nM of methyl violet 2B in A375P cancer cells. To the best of our knowledge, it has never been reported that methyl violet possesses anti-cancer effects. Moreover, methyl violet 2B significantly inhibited FER kinase phosphorylation that activates FAK in cell. In addition, methyl violet 2B was found to induce cell apoptosis and to exhibit strong inhibitory effects on the focal adhesion, invasion, and migration of A375P cancer cells at low nanomolar concentrations. Taken together, these results show that methyl violet 2B is a novel, potent and selective blocker of FAK signaling cascade, which displays strong anti-proliferative activities against a variety of human cancer cells and suppresses adhesion/migration/invasion of tumor cells.

Kim, Hwan [Chemical Kinomics Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of) [Chemical Kinomics Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Translational Research Center for Protein Function Control (TRCP), Department of Biotechnology and Department of Biomedical Sciences (WCU Program), Yonsei University, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Nam Doo [Daegu-Gyeongbuk Medical Innovation Foundation, 2387 Dalgubeol-daero, Suseong-gu, Daegu 706-010 (Korea, Republic of)] [Daegu-Gyeongbuk Medical Innovation Foundation, 2387 Dalgubeol-daero, Suseong-gu, Daegu 706-010 (Korea, Republic of); Lee, Jiyeon [Chemical Kinomics Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)] [Chemical Kinomics Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Han, Gyoonhee [Translational Research Center for Protein Function Control (TRCP), Department of Biotechnology and Department of Biomedical Sciences (WCU Program), Yonsei University, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)] [Translational Research Center for Protein Function Control (TRCP), Department of Biotechnology and Department of Biomedical Sciences (WCU Program), Yonsei University, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Sim, Taebo, E-mail: tbsim@kist.re.kr [Chemical Kinomics Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of) [Chemical Kinomics Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); KU-KIST Graduate School of Converging Science and Technology, 145, Anam-ro, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

2013-07-26

409

Use of cellulose-based wastes for adsorption of dyes from aqueous solutions.  

PubMed

Low-cost banana and orange peels were prepared as adsorbents for the adsorption of dyes from aqueous solutions. Dye concentration and pH were varied. The adsorption capacities for both peels decreased in the order methyl orange (MO) > methylene blue (MB) > Rhodamine B (RB) > Congo red (CR) > methyl violet (MV) > amido black 10B (AB). The isotherm data could be well described by the Freundlich and Langmuir equations in the concentration range of 10-120 mg/l. An alkaline pH was favorable for the adsorption of dyes. Based on the adsorption capacity, it was shown that banana peel was more effective than orange peel. Kinetic parameters of adsorption such as the Langergren rate constant and the intraparticle diffusion rate constant were determined. For the present adsorption process intraparticle diffusion of dyes within the particle was identified to be rate limiting. Both peel wastes were shown to be promising materials for adsorption removal of dyes from aqueous solutions. PMID:12031611

Annadurai, Gurusamy; Juang, Ruey-Shin; Lee, Duu-Jong

2002-06-10

410

Stability of holographic gratings recorded in photopolymer films using different dyes  

NASA Astrophysics Data System (ADS)

In this study, stability of holographic gratings recorded in four photopolymer films with different dyes was experimentally examined. Also, dye concentration was optimized to get high diffraction efficiency. Each film contains triethanolamine and acrylamide in polyvinyl alcohol matrix, and one type of dye: eosin Y, methyl violet, rhodamine B or rose bengal. Dye concentrations were adjusted so that transmittances of the four films 60 ?m thick were approximately 94%. The photopolymer films were exposed by two intersecting beams of a YVO laser at 532 nm to form holographic grating with spatial frequency of 653 line/mm until the diffraction efficiency reached its maximum. The power of each recording beam was 10 mW, and its diameter was 2.25 mm each. Diffraction efficiency was measured using a YVO laser beam for the recorded films undergoing either 300 sec reconstruction or 5-day dark storage. The photopolymer film containing eosin Y showed the best stability both for a 300 sec reconstruction and for 5-day storage. Regarding optimization of dye concentration, the diffraction efficiencies of more than 60 % were obtained when an amount of eosin Y is between 1 mg and 50 mg, which was solved in 9.1 % polyvinyl alcohol aqueous solution of 110 g.

Tsuchida, Keiichi; Ohkawa, Masashi; Sekine, Seishi

2006-03-01

411

Spectral properties of naphthalimide dyes mixed with 4-heptyl-4'-cyanobiphenyl (7CB) in Langmuir-Blodgett films  

NASA Astrophysics Data System (ADS)

Langmuir-Blodgett (LB) films formed of some fluorescent dyes, namely derivatives of 4-aminonaphthalimide, and their binary mixtures with the liquid crystal 4-heptyl-4'-cyanobiphenyl (7CB) have been studied. The electronic absorption and fluorescence spectra were recorded. On the basis of these spectra, the spectral properties of the dyes and the intermolecular interactions in ultrathin ordered films were determined. The conclusions about the tendency to the creation of aggregates by dye molecules in LB films have been drawn. The measurements of absorption by using linearly polarised light have allowed us to determine the arrangement of the dye and liquid crystal molecules on the air-solid substrate interface.

Bielejewska, N.; Chrzumnicka, E.; Stolarski, R.; Bauman, D.

2010-06-01

412

Water soluble laser dyes  

DOEpatents

Novel water soluble dyes of the formula I are provided ##STR1## wherein R.sup.1 and R.sup.4 are alkyl of 1 to 4 carbon atoms or hydrogen; or R.sup.1 -R.sup.2 or R.sup.2 -R.sup.4 form part of aliphatic heterocyclic rings; R.sup.2 is hydrogen or joined with R.sup.1 or R.sup.4 as described above; R.sup.3 is --(CH.sub.2).sub.m --SO.sub.3.sup.-, where m is 1 to 6; X is N, CH or ##STR2## where Y is 2 --SO.sub.3.sup.- ; Z is 3, 4, 5 or 6 --SO.sub.3.sup.-. The novel dyes are particularly useful as the active media in water solution dye lasers.

Hammond, Peter R. (Livermore, CA); Feeman, James F. (Wyomissing, PA); Field, George F. (Santa Ana, CA)

1998-01-01

413

VIS absorption spectrophotometry of disperse dyes  

Microsoft Academic Search

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the

Vera Golob; Lidija Tušek

1999-01-01

414

Dye filled security seal  

SciTech Connect

A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member.

Wilson, Dennis C. W. (Tijeras, NM)

1982-04-27

415

A method for evaluating the use of fluorescent dyes to track proliferation in cell lines by dye dilution.  

PubMed

Labeling nonquiescent cells with carboxyfluorescein succinimidyl ester (CFSE)-like dyes gives rise to a population width exceeding the threshold for resolving division peaks by flow cytometry. Width is a function of biological heterogeneity plus extrinsic and intrinsic error sources associated with the measurement process. Optimal cytometer performance minimizes extrinsic error, but reducing intrinsic error to the point of facilitating peak resolution requires careful fluorochrome selection and fluorescent cell sorting. In this study, we labeled the Jurkat and A549 cell lines with CFSE, CellTraceViolet (CTV), and eFluor 670 proliferation dye (EPD) to test if we could resolve division peaks in culture after reducing the labeled input widths by cell sorting. Reanalysis of the sorted populations to ascertain the level of reduction achieved always led to widths exceeding the gated limits due to the contribution of errors. Measuring detector-specific extrinsic error by sorting uniform fluorescent particles with similar spectral properties to the tracking dyes allowed us to determine the intrinsic error for each dye and cell type using a simple mathematical approach. We found that cell intrinsic error ultimately dictated whether we could resolve division peaks, and that as this increased, the required sort gate width to resolve any division peaks decreased to the point whereby issues with yield made A549 unsuitable for this approach. Finally, attempts to improve yields by setting two concurrent sort gates on the fluorescence distribution enriched for cells in different stages of the cell cycle that had nonequivalent proliferative properties in culture and thus should be practiced with caution. PMID:24166880

Begum, Julfa; Day, William; Henderson, Carl; Purewal, Sukhveer; Cerveira, Joana; Summers, Huw; Rees, Paul; Davies, Derek; Filby, Andrew

2013-12-01

416

Investigation of ultra violet (UV) resistance for high strength fibers  

NASA Astrophysics Data System (ADS)

Ultra long duration balloons (ULDB), currently under development by the National Aeronautics and Space Administration (NASA), requires the use of high strength fibers in the selected super-pressure pumpkin design. The pumpkin shape balloon concept allows clear separation of the load transferring functions of the major structural elements of the pneumatic envelope, the tendons and the film. Essentially, the film provides the gas barrier and transfers only local pressure load to the tendons. The tendons, in the mean time, provide the global pressure containing strength. In that manner, the strength requirement for the film only depends on local parameters. The tendon is made of p-phenylene-2,6-benzobisoxazole (PBO) fibers, which is selected due to its high strength to weight ratio when compared to other high performance, commercially available, fibers. High strength fibers, however, are known to degrade upon exposure to light, particularly at short wavelengths. This paper reports the results of an investigation of the resistance of four commercial high strength fibers to ultra violet (UV) exposure. The results indicate that exposing high strength fibers in continuous yarn form to UV led to serious loss in strength of the fibers except for Spectra® fibers. The adverse changes in mechanical behavior occurred over short duration of exposure compared to the 100 day duration targeted for these missions. UV blocking finishes to improve the UV resistance of these fibers are being investigated. The application of these specially formulated coatings is expected to lead to significant improvement of the UV resistance of these high performance fibers. In this publication, we report on the mechanical behavior of the fibers pre- and post-exposure to UV, but without application of the blocking finishes.

Said, M. A.; Dingwall, Brenda; Gupta, A.; Seyam, A. M.; Mock, G.; Theyson, T.

417

Infrared Dye Laser Study.  

National Technical Information Service (NTIS)

The feasibility of a flash lamp pumped, near infrared dye laser operating at a moderate repetition rate was shown. The laser produced output pulses of 17 kw peak power at a rate of 4 pulses per minute. The flow system that is essential for multiflash oper...

1973-01-01

418

Alzheimer's Dye Test?  

ERIC Educational Resources Information Center

Massachusetts Institute of Technology (MIT) scientists have developed a new dye that could offer noninvasive early diagnosis of Alzheimer's disease, a discovery that could aid in monitoring the progression of the disease and in studying the efficacy of new treatments to stop it. The work is published in Angewandte Chemie. Today, doctors can only…

Science Teacher, 2005

2005-01-01

419

Pyranoquinoline Laser Dyes.  

National Technical Information Service (NTIS)

The patent application pertains to 2-keto-6,7,8,9-tetrahydro-2H-pyrano(3,2-g)-quinoline and 2-keto-9-methyl-6,7,8,9-tetrahydro-2H-pyrano(3,2-g)-quinoline, compounds useful as laser dyes, which are prepared from 7-hydroxy-1,2,3,4-tetrahydroquinoline.

P. R. Hammond E. J. Schimitschek J. Trias

1976-01-01

420

Optical Axis Gratings in Liquid Crystals and Their Use for Polarization Insensitive Optical Switching  

NASA Astrophysics Data System (ADS)

The ability of optical axis gratings (OAGs) to fully transfer the energy of an unpolarized incident light beam into the ±1st diffraction orders is explored below for development of a polarization-independent optical system with nonlinear transmission. Diffractive properties of OAGs based on azo dye doped liquid crystals (azo LCs) are efficiently controlled with low power radiation. Switching from diffractive to transmissive states of the OAG takes place within 50 ms at 60 W/cm2 power density level, while the diffractive state is restored within ~ 1 s in the absence of radiation. High contrast optical switching is demonstrated with violet as well as green laser beams. A photoswitchable OAG is paired with a light-insensitive OAG in diffraction compensation configuration to obtain an optical system switchable from high to low transmission state. The thinness of OAGs required for high contrast switching ensures high overall transmission of the system. Given also the spectrally and angularly broadband nature of OAG diffraction and the capability of azo LC material systems to respond both to cw as well as short laser pulses makes the optical system under discussion very promising for optical switching applications. Presentation of these results is preceded by an "opinionated" review of prior developments and demystifying of the fabrication technique of high efficiency large area OAGs.

Nersisyan, S. R.; Tabiryan, N. V.; Steeves, D. M.; Kimball, B. R.

421

Photochemistry of coumarin laser dyes  

SciTech Connect

Coumarin laser dyes are widely used in dye lasers for the generation of tunable laser light in the blue-green spectral region. As in the case with most laser dyes, coumarin dyes undergo photochemical reactions that interfere with simulated emission and result in loss of laser power output. This thesis describes the photochemistry of coumarin laser dyes under both anaerobic and aerobic conditions and some attempts to extend the useful lifetime of several dyes in dye lasers. Irradiation of Coumarin 311, 7-dimethylamino-4-methyl-coumarin (15), in oxygen-free ethanol solution results in the inefficient dye destruction. Products formed absorb light at the lasing wavelength of the dye, interfere with stimulated emission, and decrease the power output of the dye laser. Addition of the sulfur free radical chain transfer agents ethanethiol and ethyl disulfide retard the rate of formation of photoproducts absorbing at the lasing wavelengths. Deuterium incorporation, from the irradiation of Coumarin 311 in the presence of ethanethiol-S-d and ethyl disulfide, indicates that photoproducts most likely result from the reactions of free radicals which are generated in a bimolecular reaction between excited Coumarin 311 and ground state Coumarin 311. Ethanethiol and ethyl disulfide are shown to decrease the rate of power loss from a Coumarin 1 (3) dye laser. The naturally occurring amino acid cysteine acts similarly.

von Trebra, R.J.

1984-01-01

422

Kinetics and thermodynamics of textile dye adsorption from aqueous solutions using babassu coconut mesocarp.  

PubMed

Extracted babassu coconut (Orbignya speciosa) mesocarp (BCM) was applied as a biosorbent for aqueous Blue Remazol R160 (BR 160), Rubi S2G (R S2G), Red Remazol 5R (RR 5), Violet Remazol 5R (VR 5) and Indanthrene Olive Green (IOG) dye solutions. The natural sorbent was processed batchwise while varying several system parameters such as stirring time, pH and temperature. The interactions were assayed with respect to both pseudo-first-order and second-order reaction kinetics, with the latter the more suitable kinetic model. The maximum adsorption was obtained at pH 1.0 for all dyes due to available anionic groups attached to the structures, which can be justified by pH(pzc) 6.7 for the biosorbent BCM. The ability of babassu coconut mesocarp to adsorb dyes gave the order R S2G>VR 5>BR 160>IOG>RR 5, which data were best fit to Freundlich model, but did not well-adjusted for all dyes. The dye/biopolymer interactions at the solid/liquid interface are all spontaneous as given by free Gibbs energy, with exothermic enthalpic values of -26.1, -15.8, -17.8, -15.8 and -23.7 kJ mol(-1) for BR 160, R S2G, RR 5, IOG and VR 5, respectively. In spite of the negative entropic values contribution, the set of thermodynamic data is favorable for all dyes removal. However, the results pointed to the effectiveness of the mesocarp of babassu coconut as a biosorbent for removing textile dyes from aqueous solutions. PMID:19150173

Vieira, Adriana P; Santana, Sirlane A A; Bezerra, Cícero W B; Silva, Hildo A S; Chaves, José A P; de Melo, Júlio C P; da Silva Filho, Edson C; Airoldi, Claudio

2009-07-30

423

Ultra-violet excited laser emission in Na2  

NASA Astrophysics Data System (ADS)

Laser emission at different wavelengths in the range of 903 914 nm and around 2.5 ?m has been observed upon excitation of Na2 by uv radiation from an excimer laser at 351 nm and an excimer pumped dye laser in this wavelength range. The emission is attributed to a cascade emissionC^1 Pi _u to 2^1 sum _g^ + followed by2^1 sum _g^ + to A^1 sum _u^ + . In addition, coupled with the laser emission around 910 nm, broad-band fluorescence peaking around 855.5 nm is observed which, eventually, may be the first observation of theb^3 sum _g^ + to x^3 sum _u^ + bound-free transition in Na2.

Shahdin, S.; Wellegehausen, B.; Ma, Z. G.

1982-11-01

424

Localization of the Violet and Yellow Receptor Cells in the Crayfish Retinula  

PubMed Central

Cellular identification of color receptors in crayfish compound eyes has been made by selective adaptation at 450 nm and 570 nm, wavelengths near the ?max's of the two retinular cell classes previously demonstrated. By utilizing earlier evidence, the concentration of lysosome-related bodies (LRB) was used to measure relative light adaptation and thus wavelength sensitivity in 665 retinular cells from six eyes. The observed particle distributions demonstrate the following. Both violet and yellow receptors occur ordinarily in each retinula. Of the seven regular retinular cells two (R3 and R4 using Eguchi's numbering [1965]) have mean sensitivities significantly greater to violet and less to yellow than the other five. The latter apparently comprise "pure" yellow receptors (R1 and R7) and mixed yellow and violet receptors (R2, R5, and R6). Explanations of such ambiguity requiring two visual pigments in single retinular cells or intercellular coupling of adjacent neuroreceptors are apparently precluded by previous evidence. Present data imply alternatively some positional variability in the violet pair's location in individual retinulas. Thus R3 and R4 are predominantly the violet receptors but in some retinulas R2 and R3 or R4 and R5 (or rarely some other cell pairs) may be. The retinal distribution of such variations has yet to be determined. In agreement with intracellular recordings the blue and yellow cells here identified belong to both the vertical and horizontal e-vector sensitive channels.

Eguchi, Eisuke; Waterman, Talbot H.; Akiyama, Jiro

1973-01-01

425

Molecular aggregation of naphthalimide dyes in Langmuir-Blodgett films  

NASA Astrophysics Data System (ADS)

Langmuir-Blodgett (LB) films formed of some naphthalimide dyes, namely derivatives of 4-aminonaphthalimide, mixed with arachidic acid have been studied. The electronic absorption and fluorescence spectra were recorded. The results obtained have led to conclusions about formation of self-aggregates of dye molecules. The absorption spectra have indicated that in the ground electronic state, depending on the molecular structure of substituents to the main core of the dye molecule, some fractions of J-type and/or H-type aggregates can be created. The fluorescence spectra have been dominated by the emission from excimer states. The efficiency of fluorescence has been dependent on the dye content and the number of layers in LB films. Comparison of the results of this study with those obtained previously for these same dyes mixed with the thermotropic liquid crystal 4-heptyl-4'-cyanobiphenyl has revealed that the interactions among dye molecules in monolayers formed at interfaces are strongly affected by a compound used as a supporting matrix.

Bielejewska, Natalia; Bauman, Danuta

2011-05-01

426

Global Ultra-Violet Ionosphere-Thermosphere Observatory (GUVITO)  

NASA Astrophysics Data System (ADS)

UV spectrographic imagers such as SSUSI and GUVI provide measurements of the aurora, ionospheric electron density, ionospheric bubbles, and thermospheric temperature, composition, and density. These imagers have been a key element of the Air Force DMSP program, but to accommodate new satellite concepts and maintain flexibility in the choice of new space systems and launch options, lighter weight and more capable UV instruments are needed to replace the current series of SSUSI sensors. Here we describe a technological alternative to the currently flying SSUSI sensors. It is a spectrographic imaging capability known as the “Global Ultra-Violet Ionosphere-Thermosphere Observatory” (GUVITO) sensor and associated software. GUVITO improves upon current instruments by being smaller in size, weight and power but with improved functionality. The GUVITO sensor represents an upgrade of the SSUSI and GUVI sensors in terms of scan mirror functionality and reliability, sensor functionality, mass, and power requirements. In particular, this improved functionality is expected to lead to enhanced capability in observing ionospheric bubbles, which are thought to cause scintillation and serious technological challenges for communications, navigation and surveillance systems. Initial development and risk reduction activities are currently funded by AFRL through a SBIR Phase II contract. The enhanced reliability and performance of the GUVITO sensor system is achieved with flight heritage components, concepts, software, hardware and is guided by key personnel experienced with both the SSUSI and GUVI hardware, software and operations. GUVITO would meet DoD priority requirements in ionospheric density, scintillation, and satellite drag, meet NPOESS IORD-II requirements for space environment Environmental Data Records (EDRs), maintain current DMSP capability, ensure long-term continuity of space environmental monitoring and leverage new technology development for future operational systems. The existing SSUSI/GUVI design consists of a scanning imaging spectrograph with a cross-track scanning mirror at the input to an off-axis parabaloid telescope which feeds a Rowland Circle spectrograph. A toroidal grating disperses the wavelength and focuses the UV photons onto a two-dimensional photon-counting detector. The detector is effectively divided into a number of spatial elements along the spacecraft track and into a number of spectral bins cross-track over the range of 115 nm to 180 nm. Full spectral information can be collected for each spatial element, but it is sufficient to save and telemeter only the spectral bins associated with selected emission lines and bands. These are mission-selectable. We find that a minimum number of colors is five, corresponding to the most significant key products that we will provide. This presentation will demonstrate and discuss some of the GUVITO capabilities in detail, together with assimilation techniques that could be used for ionospheric specification.

Curtis, N.; Crowley, G.; Christensen, A. B.; Paxton, L. J.; Robichaud, J.; Barry, M. A.; Bust, G. S.

2009-12-01

427

Performing Vaginal Lavage, Crystal Violet Staining, and Vaginal Cytological Evaluation for Mouse Estrous Cycle Staging Identification  

PubMed Central

A rapid means of assessing reproductive status in rodents is useful not only in the study of reproductive dysfunction but is also required for the production of new mouse models of disease and investigations into the hormonal regulation of tissue degeneration (or regeneration) following pathological challenge. The murine reproductive (or estrous) cycle is divided into 4 stages: proestrus, estrus, metestrus, and diestrus. Defined fluctuations in circulating levels of the ovarian steroids 17-?-estradiol and progesterone, the gonadotropins luteinizing and follicle stimulating hormones, and the luteotropic hormone prolactin signal transition through these reproductive stages. Changes in cell typology within the murine vaginal canal reflect these underlying endocrine events. Daily assessment of the relative ratio of nucleated epithelial cells, cornified squamous epithelial cells, and leukocytes present in vaginal smears can be used to identify murine estrous stages. The degree of invasiveness, however, employed in collecting these samples can alter reproductive status and elicit an inflammatory response that can confound cytological assessment of smears. Here, we describe a simple, non-invasive protocol that can be used to determine the stage of the estrous cycle of a female mouse without altering her reproductive cycle. We detail how to differentiate between the four stages of the estrous cycle by collection and analysis of predominant cell typology in vaginal smears and we show how these changes can be interpreted with respect to endocrine status.

McLean, Ashleigh C.; Valenzuela, Nicolas; Fai, Stephen; Bennett, Steffany A.L.

2012-01-01

428

Performing vaginal lavage, crystal violet staining, and vaginal cytological evaluation for mouse estrous cycle staging identification.  

PubMed

A rapid means of assessing reproductive status in rodents is useful not only in the study of reproductive dysfunction but is also required for the production of new mouse models of disease and investigations into the hormonal regulation of tissue degeneration (or regeneration) following pathological challenge. The murine reproductive (or estrous) cycle is divided into 4 stages: proestrus, estrus, metestrus, and diestrus. Defined fluctuations in circulating levels of the ovarian steroids 17-?-estradiol and progesterone, the gonadotropins luteinizing and follicle stimulating hormones, and the luteotropic hormone prolactin signal transition through these reproductive stages. Changes in cell typology within the murine vaginal canal reflect these underlying endocrine events. Daily assessment of the relative ratio of nucleated epithelial cells, cornified squamous epithelial cells, and leukocytes present in vaginal smears can be used to identify murine estrous stages. The degree of invasiveness, however, employed in collecting these samples can alter reproductive status and elicit an inflammatory response that can confound cytological assessment of smears. Here, we describe a simple, non-invasive protocol that can be used to determine the stage of the estrous cycle of a female mouse without altering her reproductive cycle. We detail how to differentiate between the four stages of the estrous cycle by collection and analysis of predominant cell typology in vaginal smears and we show how these changes can be interpreted with respect to endocrine status. PMID:23007862

McLean, Ashleigh C; Valenzuela, Nicolas; Fai, Stephen; Bennett, Steffany A L

2012-01-01

429

Post-Katrina fecal contamination in Violet Marsh near New Orleans.  

PubMed

Fecal material entrained in New Orleans flood waters was pumped into the local environment. Violet Marsh received water pumped from St. Bernard Parish and the Lower Ninth Ward. Sediment core samples were collected from canals conducting water from these areas to pump stations and from locations within Violet Marsh. Viable indicator bacteria and fecal sterols were used to assess the levels of fecal material in sediment deposited after the levee failures and deeper sediments deposited before. Most of the cores had fecal coliform levels that exceed the biosolids criterion. All of the cores had fecal sterols that exceeded the suggested environmental quality criterion. Our data show both a long history of fecal contamination in Violet Marsh and an increase in fecal loading corresponding to the failure of the levee system. The work was performed as part of the Interagency Performance Evaluation Task Force investigation into the consequences of the failures of the New Orleans levee system. PMID:17617670

Furey, John S; Fredrickson, Herbert; Foote, Chris; Richmond, Margaret

2007-06-01

430

Post-Katrina Fecal Contamination in Violet Marsh near New Orleans  

PubMed Central

Fecal material entrained in New Orleans flood waters was pumped into the local environment. Violet Marsh received water pumped from St. Bernard Parish and the Lower Ninth Ward. Sediment core samples were collected from canals conducting water from these areas to pump stations and from locations within Violet Marsh. Viable indicator bacteria and fecal sterols were used to assess the levels of fecal material in sediment deposited after the levee failures and deeper sediments deposited before. Most of the cores had fecal coliform levels that exceed the biosolids criterion. All of the cores had fecal sterols that exceeded the suggested environmental quality criterion. Our data show both a long history of fecal contamination in Violet Marsh and an increase in fecal loading corresponding to the failure of the levee system. The work was performed as part of the Interagency Performance Evaluation Task Force investigation into the consequences of the failures of the New Orleans levee system.

Furey, John S.; Fredrickson, Herbert; Foote, Chris; Richmond, Margaret

2007-01-01

431

Painting With Natural Dyes  

NSDL National Science Digital Library

This activity is part of an integrated elementary unit called "Painted Tipis." The unit is best taught in the fall in conjunction with the September celebration "American Indian Heritage Week." It integrates lessons on literature through legends and myths, language (Blackfeet), and mathematics through structural components of the tipi. The activity introduces the students to the art of dyeing as used in ancestral tipi paintings. Historical cultural ties are an integral part of the Native American students learning and this unit provides those connections. The purpose of this lesson is to provide elementary students with the opportunity to explore, identify and locate area plants. The inquiry cooperative learning component of this lesson will be to determine the color (dye) producing possibilities of the plant. Students will also plan and carry out an experiment to produce the dyestuff of the plant as well as create possible mordants, which is a chemical or metallic compound that will "fasten" the color to the fabric.

Barbara Arrowtop (Heart Butte School)

1999-07-01

432

Dyeing of wool with natural anthraquinone dyes from Fusarium oxysporum  

Microsoft Academic Search

Two anthraquinone compounds are described which were produced by liquid cultures of Fusarium oxysporum (isolate no. 4), isolated from the roots of citrus trees affected with root rot disease. These anthraquinone compounds are 2-acetyl-3,8-dihydroxy-6-methoxy anthraquinone or 3-acetyl-2,8-dihydroxy-6-methoxy anthraquinone. Dyeing of wool fabrics with these new anthraquinone compounds as natural dyes has been studied. The values of dyeing rate constant, half-time

F. A. Nagia; R. S. R. EL-Mohamedy

2007-01-01

433

Dyeing fabrics with metals  

NASA Astrophysics Data System (ADS)

Traditionally, in textile dyeing, metals have been used as mordants or to improve the color produced by a natural or synthetic dye. In biomedical research and clinical diagnostics gold colloids are used as sensitive signals to detect the presence of pathogens. It has been observed that when metals are finely divided, a distinct color may result that is different from the color of the metal in bulk. For example, when gold is finely divided it may appear black, ruby or purple. This can be seen in biomedical research when gold colloids are reduced to micro-particles. Bright color signals are produced by few nanometer-sized particles. Dr. William Todd, a researcher in the Department of Veterinary Science at the Louisiana State University, developed a method of dyeing fabrics with metals. By using a reagent to bond the metal particles deep into the textile fibers and actually making the metal a part of the chemistry of the fiber. The chemicals of the fabric influence the resulting color. The combination of the element itself, the size of the particle, the chemical nature of the particle and the interaction of the metal with the chemistry of the fabric determine the actual hue. By using different elements, reagents, textiles and solvents a broad range of reproducible colors and tones can be created. Metals can also be combined into alloys, which will produce a variety of colors. The students of the ISCC chapter at the Fashion Institute of Technology dyed fabric using Dr. Todd's method and created a presentation of the results. They also did a demonstration of dyeing fabrics with metals.

Kalivas, Georgia

2002-06-01

434

Dye laser tuner  

SciTech Connect

A laser of the kind in which the lasing medium is a free flowing dye stream incorporates a means of tuning the output wave length of the laser, this means being in the form of a wedged birefringent plate which is driven in a linear mode by a linear translator so that the thickness of the birefringent plate traversed by the intracavity beam of laser light may be varied.

Arthurs, E.G.; Purdie, A.F.

1980-11-11

435

White light emission from polystyrene under pulsed ultra violet laser irradiation  

PubMed Central

This paper reports for the first time the luminescent property of polystyrene (PS), produced by pulsed ultra violet laser irradiation. We have discovered that, in air, ultra-violet (UV) irradiated PS nanospheres emit bright white light with the dominant peak at 510?nm, while in vacuum they emit in the near-blue region. From the comparison of PS nanospheres irradiated in vacuum and air, we suggest that the white luminescence is due to the formation of carbonyl groups on the surface of PS by photochemical oxidation. Our results potentially offer a new route and strategy for white light sources.

Kim, Eunkyeom; Kyhm, Jihoon; Kim, Jung Hyuk; Lee, Gi Yong; Ko, Doo-Hyun; Han, Il Ki; Ko, Hyungduk

2013-01-01

436

Ultraviolet pigments in birds evolved from violet pigments by a single amino acid change  

PubMed Central

UV vision has profound effects on the evolution of organisms by affecting such behaviors as mating preference and foraging strategies. Despite its importance, the molecular basis of UV vision is not known. Here, we have transformed the zebra finch UV pigment into a violet pigment by incorporating one amino acid change, C84S. By incorporating the reverse mutations, we have also constructed UV pigments from the orthologous violet pigments of the pigeon and chicken. These results and comparative amino acid sequence analyses of the pigments in vertebrates demonstrate that many avian species have achieved their UV vision by S84C.

Yokoyama, Shozo; Radlwimmer, F. Bernhard; Blow, Nathan S.

2000-01-01

437

Fabricating chiral polydiacetylene film by monolayer compression and circularly polarized ultra-violet light  

NASA Astrophysics Data System (ADS)

We study polydiacetylene films that are pertinent to the problems of mirror symmetry breaking induced by the effects of compression and circularly polarized ultra-violet (UV) light. The subphase is only pure water. After polymerization, polymerized 10,12-tricosadiynoic acid (PTDA) LB films that deposited at the surface pressure of 20 mN m -1 showed obviously chiral properties, however, no obvious Cotton effect was obtained for PTDA LB films that deposited at the surface pressure of 10 mN m -1. In addition, TDA LB films could be polymerized to a designed chirality by using chiral circular polarized ultra-violet light (CPUL).

Zou, Gang; Kohn, Hideki; Ohshima, Yuki; Manaka, Takaaki; Iwamoto, Mitsumasa

2007-07-01

438

Textile anionic dyes recovery using tri-n-butyl phosphate as carrier through supported liquid membrane.  

PubMed

The recovery of anionic dyes Acid Red10 B (CI Acid Violet 54) and Acid Pink BE (CI Acid Red 183) in flat type supported liquid membrane (SLM) using tri-n-butyl phosphate as carrier was studied. The parameters studied w