Simple synthesis of photoluminescent carbon dots from a marine polysaccharide found in shark cartilage

BACKGROUND: For more than a decade, water-soluble, eco-friendly, biocompatible, and low-toxicity fluorescent nanomaterials have received considerable attention for their numerous in vivo and in vitro applications in biomedical imaging, disease diagnostics, and environmental monitoring. Owing to their tunable photoluminescence properties, carbon-based luminescent nanomaterials have shown great potential in bioimaging, photocatalysis, and biosensing among other applications. RESULTS: Marine environments provide excellent resources for the fabrication of these nanomaterials, because many marine organisms contain interesting trigger organic compounds that can be used as precursors. Herein, we synthesize multi-color emissive carbon dots (CDs) with an intrinsic photoluminescence quantum yield of 20.46%. These nanostructures were achieved through the one-step hydrothermal treatment of marine polysaccharide chondroitin sulfate, obtained from shark cartilage, in aqueous solution. CONCLUSIONS: We successfully demonstrate the low toxicity of our marine resource-derived CDs in zebrafish, and provide an initial assessment of their possible use as a bioimaging agent. Notably, the newly synthesized CDs localize in the intestines of zebrafish larvae, thereby indicating their biocompatibility and potential use as in vivo dyes.

Decolorization of textile industry wastewater in solid state fermentation with Peach-Palm (Bactris gasipaes) residue / Decoloração de águas residuais da indústria têxtil em fermentação de estado sólido com resíduo de Pupunha (Bactris gasipaes)

Abstract In this work we have assessed the decolorization of textile effluents throughout their treatment in a solid-state fermentation (SSF) system. SSF assays were conducted with peach-palm (Bactris gasipaes) residue using the white rot fungus Ganoderma lucidum EF 31. The influence of the dye concentration and of the amounts of peach-palm residue and liquid phase on both the discoloration efficiency and enzyme production was studied. According to our results, independently of experimental conditions employed, laccase was the main ligninolytic enzyme produced by G. lucidum. The highest laccase activity was obtained at very low effluent concentrations, suggesting the existence of an inhibitory effect of higher concentrations on fungal metabolism. The highest percentage of color removal was reached when 10 grams of peach palm residue was moistened with 60 mL of the final effluent. In control tests carried out with the synthetic dye Remazol Brilliant Blue R (RBBR) decolorization efficiencies about 20% higher than that achieved with the industrial effluent were achieved. The adsorption of RBBR on peach-palm residue was also investigated. Equilibrium tests showed that the adsorption of this dye followed both Langmuir and Freundlich isotherms. Hence, our experimental results indicate that peach-palm residue is suitable substrate for both laccase production and color removal in industrial effluents.

Resumo Neste trabalho, avaliamos a descoloração de efluentes têxteis durante seu tratamento em um sistema de fermentação em estado sólido (SSF). Os ensaios foram conduzidos com resíduo de pupunha (Bactris gasipaes) utilizando o fungo de podridão branca Ganoderma lucidum EF 31. A influência da concentração de corante, as quantidades de resíduo e da fase líquida foram estudadas tanto na eficiência de descoloração como na produção de enzima. De acordo com os resultados, independentemente das condições experimentais utilizadas, a lacase foi a principal enzima ligninolítica produzida por G. lucidum. A atividade de lacase mais elevada foi obtida em baixas concentrações de efluentes, sugerindo um efeito inibitório no metabolismo fúngico. A maior remoção de cor foi obtida com 10 gramas de resíduo da pupunha e 60 mL do efluente final. Nos ensaios de controle realizados com o corante sintético RBBR, foram atingidos cerca de 20% mais descoloração do que os obtidos com o efluente industrial. A adsorção de RBBR no resíduo de pupunha também foi investigada. Os testes de equilíbrio mostraram que a adsorção deste corante seguiu as isotermas de Langmuir e Freundlich. Assim, os resultados experimentais indicam que o resíduo de pupunha é um substrato adequado tanto para a produção de lacase quanto para a remoção de cor em efluentes industriais.

Panus tigrinus as a potential biomass source for Reactive Blue decolorization: isotherm and kinetic study

Background: Textile and dye industries pose a serious threat to the environment. Conventional methods used for dye treatment are generally not always effective and environmentally friendly. This drove attention of scores of researchers to investigate alternative methods for the biodegradation of dyes using fungal strains. In this work, white-rot fungus (Panus tigrinus) was used as a biosorbent for the decolorization of Reactive Blue 19. The process parameters that were varied were initial concentration (50­150 mg/L), contact time (30­90 min), and pH (2­6). In addition, to gain important data for the evaluation of a sorption process, the equilibrium and kinetics of the process were determined. Results: White-rot fungus showed great potential in decolorizing Azo dyes. The strain showed the maximum decolorization of 83.18% at pH 2, a contact time of 90 min, and an initial concentration of 50 mg/L. The Langmuir isotherm described the uptake of the Reactive Blue 19 dye better than the Freundlich isotherm. Analysis of the kinetic data showed that the dye uptake process followed the pseudo second-order rate expression. Conclusion: The biosorption process provided vital information on the process parameters required to obtain the optimum level of dye removal. The isotherm study indicated the homogeneous distribution of active sites on the biomass surface, and the kinetic study suggested that chemisorption is the rate-limiting step that controlled the biosorption process. According to the obtained results, P. tigrinus biomass can be used effectively to decolorize textile dyes and tackle the pollution problems in the environment.

Screening of freshwater fungi for decolorizing multiple synthetic dyes

Abstract The biodegradation of synthetic dyes by fungi is emerging as an effective and promising approach. In the present study, freshwater fungal strains isolated from submerged woods were screened for the decolorization of 7 synthetic dyes. Subsequently, 13 isolates with high decolorization capability were assessed in a liquid system; they belonged to 9 different fungal species. Several strains exhibited a highly effective decolorization of multiple types of dyes. New absorbance peaks appeared after the treatment with 3 fungal strains, which suggests that a biotransformation process occurred through fungal biodegradation. These results showed the unexploited and valuable capability of freshwater fungi for the treatment of dye-containing effluents. The ability of certain fungi to decolorize dyes is reported here for the first time.

Color stability of ceramic brackets immersed in potentially staining solutions

OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions.METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%.RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations.CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

OBJETIVO: avaliar a estabilidade da cor de cinco tipos de braquetes cerâmicos após imersão em soluções potencialmente corantes.MÉTODOS: noventa braquetes foram divididos em 5 grupos (n = 18) de acordo com a marca comercial dos braquetes e as soluções em que foram imersos (café, vinho tinto, Coca-Cola e saliva artificial). Os baquetes avaliados foram Transcend (3M / Unitek, Monrovia, CA, EUA), Radiance (American Ortodontia, Sheboygan, WI, EUA), Mystique (GAC International Inc., Bohemia, NY, EUA) e Luxi II (Rocky Mountain Orthodontics, Denver, CO, EUA). Alterações cromáticas foram analisadas com o uso de um espectrofotômetro de reflectância e por inspecção visual, em cinco intervalos de tempo específicos. Os momentos de avaliação foram: 24 horas (T1), 72 horas (T2), 7 dias (T3) e 14 dias (T4) de imersão nas soluções. Os resultados foram submetidos à avaliação estatística com análise de variância e correção de Bonferroni, bem como a uma análise do perfil multivariada para amostras independentes e pareadas, com nível de significância de 5%.RESULTADOS: a duração do período de imersão influenciou na alteração de cor de todos os braquetes testados, mesmo admitindo-se que essas alterações nem sempre puderam ser observadas visualmente. Diferentes comportamentos foram observados em cada solução de imersão; no entanto, braquetes imersos em um mesmo tipo de solução progrediram de forma semelhante, apesar das pequenas variações.CONCLUSÕES: a coloração se tornou mais intensa com o tempo, e todos os braquetes sofreram alteração de cor nas soluções imersas.

Surface properties of multilayered, acrylic resin artificial teeth after immersion in staining beverages

AbstractObjective To evaluate the effect of staining beverages (coffee, orange juice, and red wine) on the Vickers hardness and surface roughness of the base (BL) and enamel (EL) layers of improved artificial teeth (Vivodent and Trilux).Material and Methods Specimens (n=8) were stored in distilled water at 37°C for 24 h and then submitted to the tests. Afterwards, specimens were immersed in one of the staining solutions or distilled water (control) at 37°C, and the tests were also performed after 15 and 30 days of immersion. Data were analyzed using 3-way ANOVA and Tukey’s test (α=0.05).Results Vivodent teeth exhibited a continuous decrease (p<0.0005) in hardness of both layers for up to 30 days of immersion in all solutions. For Trilux teeth, similar results were found for the EL (p<0.004), and the BL showed a decrease in hardness after 15 days of immersion (p<0.01). At the end of 30 days, this reduction was not observed for coffee and water (p>0.15), but red wine and orange juice continuously reduced hardness values (p<0.0004). Red wine caused the most significant hardness changes, followed by orange juice, coffee, and water (p<0.006). No significant differences in roughness were observed for both layers of the teeth during the immersion period, despite the beverage (p>0.06).Conclusions Hardness of the two brands of acrylic teeth was reduced by all staining beverages, mainly for red wine. Roughness of both layers of the teeth was not affected by long-term immersion in the beverages.

New generation of color bonding: A comparative in vitro study.

Background: Newer available composite resin adhesives have chromatic agents that change their color during setting from pink to colorless. It has an advantage of easy flash removal thus reducing the amount of plaque accumulation and helping patients to maintain better hygiene. Aim: The aim of the present study was to compare shear bond strengths of light-cure orthodontic bonding agents, namely glass ionomer (FujiOrthoLC, GC Orthodontics), conventional composite resin (Transbond XT, 3M Unitek), and color-changing composite resin (Transbond Plus, 3M Unitek) with conventional etch and self-etch primer (Transbond PlusSEP, 3M Unitek). Materials and Methods: Maxillary premolars (n=300) were bonded on the facial surface in five groups. The INSTRON machine was used for shear bond strength testing. Statistical Analysis: Comparison of the mean rank among the groups was done by Kruskal-Wallis one-way analysis of variance (ANOVA). To determine the mean difference among groups, the Mann-Whitney test with Bon Ferroni adjustment was applied. Observations: It was observed that light-cure conventional composite resin with the conventional etchant group had the highest and glass ionomer resin adhesive had the lowest shear bond strength. There was no statistically significant difference between conventional composite used with conventional etchant and color-changing composite resin used with conventional etchant or with self-etch primer. Conclusion: Considering the advantages of a color-changing composite and self-etch primer especially in patients having high DMFT scores or physically and mentally compromised patients unable to maintain their hygiene properly, it was concluded in the present study that it would be the most suitable material for direct bonding.

Ozonized oils: a qualitative and quantitative analysis

Most of the problems of endodontic origin have a bacterial etiological agent. Thus, there is a continued interest in seeking more effective chemical substances that can replace the camphorated paramonochiorophenol or antibiotics as intracanal medicaments. Among the possible substances, ozone has some interesting biological characteristics: bactericidal action, debriding effect, angiogenesis stimulation capacity and high oxidizing power. The purpose of this study was to chemically evaluate the presence of ozone in sunflower, castor, olive and almond oil, as well as in propylene glycol and byproducts of ozonation, such as formaldehyde. These compounds were ozonized, inserted into empty and sterile vials, and analyzed by testing the reaction between ozone and indigo, for determining the presence of ozone, and subjected to the chromotropic acid test for determining the presence of formaldehyde. It was observed complete absence of ozone in all samples tested and presence of formaldehyde. The bactericidal and healing action of ozonized oils could be attributed to products formed by the ozonation of mineral oils, such as formaldehyde, not to the ozone itself.

A maioria dos problemas de origem endodôntica tem um agente etiológico bacteriano. Assim, existe um interesse permanente em se buscar substâncias químicas mais efetivas e que possam substituir o PMCC ou os antibióticos como curativos de demora. Dentre as possíveis substâncias, o ozônio apresenta algumas características biológicas interessantes: ação bactericida, efeito debridante, estímulo a angiogênese, além do efeito oxidante. O propósito do presente estudo foi avaliar quimicamente a presença de ozônio nos óleos de girassol, rícino, oliva e amêndoas, além do propilenoglicol, bem como subproputos da ozonização, como formaldeído. Essas substâncias foram ozonizadas, inseridas em tubetes anestésicos vazios e esterilizados, e analisadas por meio do teste da reação entre ozônio e índigo, para determinação da presença de ozônio; e teste do ácido cromotrópico, para determinação da presença de formaldeído. Foi observado ausência total de ozônio em todas as amostras testadas, além da presença de formaldeído. A ação bactericida e curativa dos óleos ozonizados poderia ser atribuída aos produtos formados pela ozonização de óleos minerais, como o formaldeído, e não ao ozônio propriamente dito.

Análise quantitativa do corante azul de Evan extravasado do interior das câmaras internas dos implantes por suas interfaces protéticas nas condições: Hexágono Externo (HE) - Hexágono Interno (HI) - Cone Morse (CM) / Quantitative analysis of Evans blue dye leakage from internal implant chambers through their prosthetic interfaces under the following conditions: External Hexagon (HE) Internal Hexagon (IH) Morse Cone (MC)

Busca-se em pesquisas e estudos avaliar a capacidade de adaptação e selamento entre a conexão implante/intermediário de diferentes sistemas de implantes odontológicos. Observou-se recentemente que implantes com abutments retidos com parafusos, diversos fenômenos como afrouxamento e fratura do parafuso, rotação e fratura do abutment com penetração bacteriana nas câmaras internas dos implantes, acontece como conseqüência da desadaptação interface implante/abutment. É descrito ao nível desta região um pequeno espaço microgap, fator relevante para remodelamento da crista óssea e longevidade da saúde dos tecidos moles periimplantares. O propósito do estudo foi investigar o extravasamento da solução do corante azul de Evan em três tipos de implantes e seus respectivos intermediários, durante um período de seis (6) dias, a cada vinte e quatro (24) horas, com intervalo em cento e vinte (120) horas, através da agitação proporcionada por uma mesa agitadora. Para tal, foram utilizados trinta (30) implantes, dez (10) de cada tipo, com seus respectivos intermediários protéticos, minipilares, sendo o Grupo Um (1) de implantes Hexágono Externo (HE), Grupo dois (2) de Hexágono Interno (HI) e Grupo três (3) de Cone Morse (CM). No interior de cada implante foi pipetado volume ou quantidade proporcional ao seu espaço interno uma solução de corante azul de Evan. Após a colocação do corante no interior dos implantes, os abutments ou intermediários foram acoplados e aparafusados com torque de vinte (20) Ncm, através do torquímetro de Gauge (Tohnichi), e estes depositados individualmente em micro tubos de cor âmbar na condição de intermediários voltados para baixo. Segui/se imediatamente a colocação de (1)ml de água deionizada. A seguir os tubos foram fechados hermeticamente e posicionados numa mesa suporte para microtubos e foram armazernados por 24 horas, sem agitação. Posteriormente foram agitados por 10 minutos com movimentos uniformes em mesa agitadora e a partir deste momento...

Research and studies seek to evaluate the capacity of adaptation and sealing between the implant-intermediate connections of different dental implant systems. It has recently been observed that in implants with screw-retained abutments, various phenomena, such as screw4 loosening and fracture, rotation and fracture of the abutment with bacterial penetration into the internal chambers of the implants have occurred as a result of maladaptatation at the implant-abutment interface. At the level of this region, a small space known as a microgap is described, and is a relevant factor in remodeling of the crestal bone and peri-implant soft tissue health in the long term. The purpose of this study was to investigate the extravasation of Evans blue dye solution in three types of implants and their respective intermediates during a period of six (6) days, every twenty-four (24) hours, with an interval in one hundred and wenty (120) hours, by means of agitation provided by an agitating table. To do this, thirty (30) implants were used, ten (10) of each type, with their respective prosthetic intermediates and mini-abutments, divided into groups as follows: Group One (1) External Hexagon implants (EH), Group Two (2) Internal Hexagon (IH) and Group three (3) Morse Cone (MC). Into the interior of each implant, Evans blue dye solution was inserted with a pipette in a volume or quantity proportional to its internal space. After the dye was put into the implants, the abutments or intermediates were coupled and the screws tightened to a torque of twenty (20) Ncm, with a Gauge torque meter (Tohnichi), and they were individually deposited in amber-colored microtubes positioned so that the intermediates faced downwards. This was immediately followed by the placement of (1)ml of deionized water. Next, the tubes were hermetically closed and placed on a table with a microtube holder and stored for 24 hours, without agitation. Afterwards they were agitated for 10...

Effect of photochemical activation of hydrogen peroxide bleaching gel with and without TiO 2 and different wavelengths

Aim: To evaluate the effect of photochemical activation of hydrogen peroxide (H2O2) bleaching gel with different wavelengths. Methods: In the study, 80 bovine incisors were used, which were stained in 25% soluble coffee and divided in 4 groups. The initial color was measured with the Easy Shade spectrophotometer by CIE Lab. An experimental 35% H2O2 bleaching gel was used,either with or without the presence of titanium dioxide (TiO2) pigment, associated with two light sources: G1 - Transparent Gel (TG) and no activation; G2 - Gel with TiO2 and activation with blue LED (l=470nm)laser (Easy Bleach) appliance; G3 - Gel with TiO2 and activation with ultraviolet(l=345nm - UV); G4 - TG and activation with UV. Three applications of the gels were made for 10min, and in each, 3 activations of 3 min, with interval of 30 s between them. The coloration was evaluated again and the variation in color perception (DE) was calculated. The data were submitted to one-way ANOVA and Tukey’s test at 5% significance level. Results: There were significant differences between G1 and G4. The greatest “E value was observed in G4 (13.37).There was no statistically significant difference (p>0.05) between the groups 2, 3 and 4.Conclusions: The presence of TiO2 particules in the bleaching gel did not interfere at the bleaching results.

Effect of staining solutions and repolishing on color stability of direct composites

OBJECTIVES: The purpose of this study was to assess the color change of three types of composite resins exposed to coffee and cola drink, and the effect of repolishing on the color stability of these composites after staining. MATERIALS AND METHODS: Fifteen specimens (15 mm diameter and 2 mm thick) were fabricated from microhybrid (Esthet-X; Dentsply and Filtek Z-250; 3M ESPE) and high-density hybrid (Surefil; Dentsply) composites, and were finished and polished with aluminum oxide discs (Sof-Lex; 3M ESPE). Color of the specimens was measured according to the CIE L*a*b* system in a refection spectrophotometer (PCB 6807; BYK Gardner). After baseline color measurements, 5 specimens of each resin were immersed in different staining solutions for 15 days: G1 - distilled water (control), G2 - coffee, G3 - cola soft drink. Afterwards, new color measurement was performed and the specimens were repolished and submitted to new color reading. Color stability was determined by the difference (ΔE) between the coordinates L*, a*, and b* obtained from the specimens before and after immersion into the solutions and after repolishing. RESULTS: There was no statistically signifcant difference (ANOVA, Tukey's test; p>0.05) among the ΔE values for the different types of composites after staining or repolishing. For all composite resins, coffee promoted more color change (ΔE>3.3) than distilled water and the cola soft drink. After repolishing, the ΔE values of the specimens immersed in coffee decreased to clinically acceptable values (ΔE<3.3), but remained signifcantly higher than those of the other groups. CONCLUSIONS: No signifcant difference was found among composite resins or between color values before and after repolishing of specimens immersed in distilled water and cola. Immersing specimens in coffee caused greater color change in all types of composite resins tested in this study and repolishing contributed to decrease staining to clinically acceptable ΔE values.

Corantes vitais em cromovitrectomia / Vital dyes in chromovitrectomy

O objetivo do artigo é apresentar os dados atuais da aplicação de corantes vitais durante cirurgia vitreorretiniana, "cromovitrectomia", bem como uma revisão da literatura atual sobre o assunto no tocante às técnicas de aplicação, indicações e complicações em cromovitrectomia. Um grande número de publicações tem abordado o perfil tóxico da indocianina verde na cromovitrectomia. Dados experimentais mostram uma toxicidade dose-dependente da mesma em várias populações de células retinianas. Novas gerações de corantes incluem: azul tripan, azul patente, acetato de triancinolona, infracianina verde, fluoresceína sódica, azul de bromofenol, acetato de fluorometolona e azul brilhante. Novos instrumentos podem permitir um corar seletivo de estruturas durante a vitrectomia. Este artigo mostra que o campo da cromovitrectomia está em plena expansão de pesquisas. Os corantes de primeira linha são a indocianina verde, infracianina verde e o azul brilhante. Azul patente, azul de bromofenol e azul tripan surgem como novos adjuvantes para melhor observação da membrana epirretiniana. Demais corantes que surgiram merecem maior investigação.

The aim of this article is to present the current data with regard to the application of vital dyes during vitreoretinal surgery, "chromovitrectomy", as well as to overview the current literature regarding the properties of dyes, techniques of application, indications and complications in chromovitrectomy. A large body of published research has recently addressed the toxicity profile of indocyanine green for chromovitrectomy. Experimental data demonstrate dose-dependent toxicity of indocyanine green to various retinal cells. Newer generation vital dyes for chromovitrectomy include trypan blue, patent blue, triamcinolone acetonide, infracyanine green, sodium fluorescein, bromophenol blue, fluorometholone acetate and brilliant blue. Novel instruments may enable a selective painting of preretinal tissues during chromovitrectomy. This review suggests that the field of chromovitrectomy represents an expanding area of research. The first line agents for internal limiting membrane staining in chromovitrectomy are indocyanine green, infracyanine green, and brilliant blue. Patent blue, bromophenol blue and trypan blue arose as outstanding biostains for visualization of epiretinal membranes. Novel dyes available for chromovitrectomy deserve further investigation.

Color stability of a nanofill composite: effect of different immersion media

OBJECTIVE: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in different immersion media. MATERIALS AND METHODS: Twelve resin-based composite specimens were prepared using a silicon cylindrical mold measuring ≅1mm of thickness and ≅ 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at 1400 mW/cm² and were randomized into 4 groups (n= 3) according to immersion media: coffee, yerba mate, grape juice or water (control solution). A digital spectrophotometer was used to evaluate the color changes at baseline and at 1-week after immersion in each solution. Specimens were stored in the different staining media for 4 h/day during 1 week. The color differences (DE) were analyzed by paired t-test and one-way ANOVA with complementary Tukey test (p<0.05). RESULTS: After 1-week of immersion, a perceptive color change for the group stored in the grape juice compared to baseline (p=0.008) was observed. Coffee and yerba mate did not show any color changes visible for the human eyes or significantly different from the control group (p>0.05) CONCLUSIONS: The findings of the present study suggest that the tested nanofill resin-based composite was susceptible to staining by substances present in the grape juice.

A study on reproducing silicone shade guide for maxillofacial prostheses matching Indian skin color.

AIM: The value and success of a well-fitting and anatomically correct prosthesis are compromised if the color does not match the adjoining tissues. The use of powder colors to help develop a simplified silicone shade guide to aid in the fabrication of silicone facial prostheses for Indian patients has been described here. MATERIALS AND METHODS: Ten powder pigments were used to fabricate the silicone samples for three different subjects having light, medium and dark complexions who were separated into three groups depending on the value of their shades. Four-step wedge silicone samples with thickness variations of 1, 2, 4 and 6mm were fabricated. Visual assessment of the samples was done by four evaluators to check the agreement of color match. Data was statistically analyzed using kappa coefficients. RESULTS: The kappa values were found to be 0.09-0.44 for a light skin tone, -0.11 to 0.77 for medium skin and 0.44 to 0.85 for dark skin tones. This study showed that the samples of dark skin tone matched the skin tone well and showed a statistically good agreement. To further test the validity of these shade guides, facial silicone veneers were fabricated for three patients having light, medium and dark complexion. The color matching showed satisfactory results. CONCLUSION: The silicone veneers matched the skin color of all three patients. Hence, this shade guide will help clinicians to obtain a good intrinsic shade and minimize extrinsic coloration.

Pigmentação de próteses bucomaxilofaciais / Pigmentation of maxillofacial prostheses

Esta revisão de literatura traz informações a respeito do uso de diversos tipos de pigmentos que podem ser usados em próteses bucomaxilofaciais, assim como sua relação com os materiais empregados na confecção da prótese. Estas informações incluem alguns tipos de pigmentos (óxidos minerais, incorporados a componentes acrílicos, porcelanizados, oleosos, e outros) assim como os materiais que podem ser pigmentados, como silicone e resina acrílica, técnicas e características de cada material e tipo de pigmento. Em busca de melhores resultados não apenas na estética e longevidade das próteses, como também na manutenção das propriedades dos materiais e pigmentos, são estudados os fatores que podem causar a deterioração das mesmas, destacando a exposição à luz ultravioleta e as mudanças de condição ambiental, além da utilização de escalas de cores pré-fabricadas que facilitariam a confecção dessas próteses, permitindo economia de tempo e de material no momento da seleção da cor. Contudo, foi observado que as propriedades físicas e mecânicas do material utilizado podem variar de acordo com a adição dos pigmentos, sendo que a pigmentação extrínseca pode resultar em menor descoloração em relação à pigmentação intrínseca. Além disso, a instabilidade de cor dos materiais podem estar relacionados com vários fatores, tendo destaque a exposição à luz ultravioleta e as mudanças de condição ambiental.

This literature revision brings information regarding the use of several types of pigments that can be used in maxillofacial prostheses, as well as your relationship with the employed materials in the making of the prosthesis. This information include some types of pigments (mineral oxides, incorporate to acrylic components, porcelain, oily, and other) as well as the materials that can be pigmented, as silicon and acrylic resin, techniques and characteristics of each material and pigment type. In search of better results not just in the aesthetics and longevity of the prostheses, as well as in the maintenance of the properties of the materials and pigments, they are studied the factors that can cause to deterioration of the same ones, emphasizing the exhibition to the ultraviolet light and the changes of environmental condition, besides the use of scales of prefabricated colors that would facilitate the making of those prostheses, allowing economy of time and of material in the moment of the selection of the color. However, it was observed that the physical and mechanical properties of the used material can vary in agreement with the addition of the pigments, and the extrinsic pigmentation can result in smaller fading in relation to the intrinsic pigmentation. Besides, the instability of color of the materials can be related with several factors, tends prominence the exhibition to the ultraviolet light and the changes of environmental condition.

Removal of colour from textile effluent using cyanobacterial biomass.

The cyanobacterial species were isolated from fresh water pond of Gura-vishnoiyan and were tested for their ability to decolourise the textile effluent. The reduction in colour of textile effluent with the use of dry biomass of Cylindrospermum indicum, Nostoc calcicola, Calothrix weberi was comparatively observed after 2, 4 and 6 days, but maximum colour absorption was observed after 6 days. Calothrix weberi was found the most effective species of cyanobacteria, which can remove the colour intensity upto 85 percent after 6 days of incubation. However, Nostoc calcicola and Cylindrospermum indicum showed 45 percent and 23 percent of colour reduction respectively.

The effect of endodontic materials on the optical density of dyes used in marginal leakage studies

The aim of this study was to determine the effect of the exposure of different endodontic materials to different dye solutions by evaluating the optical density of the dye solutions. Seventy-five plastic tubes were filled with one of the following materials: AH Plus, Sealapex, Portland cement, MTA (Angelus and Pro Root) and fifteen control plastic tubes were not. Each specimen of material and control was immersed in a container with 1 ml of each dye solution. A 0.1 ml-dye solution aliquote was removed before immersion and after 12, 24, 48 and 72 hours of each specimen immersion to record its optical density (OD) in a spectrophotometer. Statistical analysis was performed with ANOVA and Tukey tests (5 percent). No significant difference was found among any of the solution OD values for AH Plus cement. Portland cement promoted different OD values after 12 hours of immersion. MTA-Angelus cement presented different OD values only for 2 percent rhodamine B and the MTA-Pro Root cement presented different OD values in all 2 percent rhodamine B samples. Sealapex cement promoted a reduction in the India Ink OD values. Dye evaluation through OD seems to be an interesting method to select the best dye solution to use in a given marginal leakage study.

Evaluation of adsorption potential of adsorbents: a case of uptake of cationic dyes.

Adsorption potential of a commercial activated carbon (FS300) has been evaluated for the uptake of cationic dyes namely methylene blue (MB) and rhodamine B (RB). Though, there are numerous studies in literature which report the sorption of MB (more than 40 studies) and RB (more than 10), however none of these use a common parameter to report the capacity of the sorbent. A protocol, based on the equilibrium dye concentration has been proposed to measure the sorption potential of a sorbent. The Langmuir model can very well describe the experimental equilibrium data for both dyes (coefficient of correlation > 0.999). MB (Qm = 312.5 mg g(-1)) is more adsorbable than the RB (Qm = 144.9 mg g(-1)). Molecular weight and chemical structure of dye molecules seem to affect the dye uptake. The effect of pH on dye uptake has also been evaluated by varyingpH from 3 to 11. Uptake of MB increases with pH, wherein RB removal decreases with pH. Dyes could not be desorbed either by distilled water (0.06 and 0.11% for MB and RB respectively), or by 0.1 NHCl (0.136 and 3.0% for MB and RB respectively) indicating, chemical adsorption type of adsorbent-adsorbate interactions.

Effect of carbon and nitrogen source amendment on synthetic dyes decolourizing efficiency of white-rot fungus, Phanerochaete chrysosporium.

Decolourization activity of Phanerochaete chrysosporium for three synthetic dyes viz., congo red, malachite green and crystal violet and impact of additional carbon and nitrogen supply on decolourization capacity of fungus were investigated. Maximum decolourizing capacity was observed up to 15 ppm. Addition of urea as nitrogen source and glucose as carbon source significantly enhanced decolourizing capacity (up to 87%) of fungus. In all the cases, both colour and COD were reduced more in non-sterilized treatments as compared to sterilized ones. Significant reductions in COD content of dye solutions (79-84%) were recorded by fungus supplied with additional carbon and nitrogen. A highly significant correlation (r = 0.78, p < 0.001) between colour and COD of dye solutions was recorded. Thus, a readily available carbon and nitrogen source is imperative to enhance the bioremediation activity of this fungus which has been the most suitable for synthetic dyes and textile industry wastewater treatment.

Dyeing of cotton fabrics using some natural dyes part II: some studies on dyeing properties of cotton fabrics using chelidonium majus [Roots]

The pre-treated cotton fabric with tannic acid [60g/l] was dyed in a bath containing natural colouring matter extracted from vegetable plants Chelidonium majus [roots]. Factors affecting dyeing properties such as concentration of colouring matter as well as pH values, time and temperature of dyeing bath were studied. It was found that the most suitable dyeing properties are obtained when colouring matter is obtained from 18 g Chelidonium majus [roots]/100 ml water using 5g/l sodium chloride, L.R 1:50, pH 6, dyeing was continued for 30 min at 70°C. Environmentally friendly mordants such as copper sulphate, ferrous sulphate, stannous chloride and alum were added using three mordanting methods: [pre-simultaneous - post] mordanting methods and overall fastness properties of dyed mordanted fabrics were assessed. In the recent years, growing interest in the revival of natural dyes has been manifested. This interest is the result of a worldwide movement to protect the environment for indiscriminate exploitation and pollution by industries. Natural dyes are considered to be complementary and not conflictive with the use of manufactured dyes in the textile industry as a whole. Chelidonium majus is an erect plant from 2-4 feet and is native to temperate Europe and Asia. Leaves are deeply pinnatifid, crenate or lobed, flowers are yellow medium sized, in a small peduncled umbel, sepals 2, petals 4; stamens many ovary of 2 carpels, fruit is a cylindrical capsule 1-2 inch long. It belongs to papaveraceae family[1]. The present work was carried out to optimize the conditions for dyeing cotton with natural colouring matter derived from Chelidonium majus [roots]. The evaluation of [K/S, L, a, b, delta E] for different dyed mordanted and/or dyed washed fabrics. Estimation of metal ions [ppm] of the dyed mordanted cotton samples [pre-treated with 60 g/l tannic acid] was carried out[9-2]