Dye Immersion Research Articles

Dye-Sensitized Solar Cells Characterization of Kitolod Leaves (Hippobroma longifora)

Energy from fossil fuels is decreasing day by day and also causes many environmental problems. In the current era, many environmentally friendly renewable energy sources have been developed, such as the development of DSSC (Dye Sensitized Solar Cells). DSSC is a technology that utilizes colored materials sourced from nature which are used as absorbers of sunlight energy to be converted into electrical energy. In this research, the synthesis and characterization of organic material from kitolod leaves as DSSC will be carried out. Kitolod leaves (Hippobroma longifora) are wild plants that usually grow in home gardens and rice fields. Kitolod leaves which have chlorophyll can support the absorption of sunlight if applied as a sensitizer in DSSC. The methods that will be used in this research are making TiO2 paste, dye solution preparation, electrolyte solution preparation, DSSC fabrication, testing and characterization. The tests that will be carried out are testing the TiO2 layer, dye absorption, and electric current. Meanwhile, the characterization that will be carried out is dye absorption using UV-Vis, and electric current using a potentiometer. From the results of light absorption shows that when the wavelength is 500 nm or the green light spectrum, the maximum light absorption by the chlorophyll of kitolod leaves is 1.78 (a.u.). The maximum voltage (Vm) and maximum current (Im) in daylight lamps have greater values ​​compared to warm white lamps. The highest efficiency of the solar light source is shown when the air mass is 1.5 (08.30-08.40). The time of DSSC immersion in dye also influences the resulting of Vm and Im values ​​which can be shown in that the Vm and Im values ​​of DSSC 2 (30 minutes) are greater than those of DSSC 1 (10 minutes). The results of open circuit voltage (Voc) and the short circuit current (Isc) in this research still need to be improved to produce better efficiency.

Influence of photoanode pre-heating treatment temperatures prior to dye immersion process on dye-sensitized solar cells photovoltaic performances

Several efforts of photoanode treatment, such as surface modification, doping introduction, defect engineering, and heating treatment, have been developed to improve the photovoltaic performances of dye-sensitized solar cells (DSSC). Amid these options, alternative routes that require less demanding conditions are highly sought. Here we introduce an effective and convenient, non-vacuum low-temperature procedure to enhance the DSSC’s photovoltaic performances by photoanode pre-heating treatment prior to the dye immersion process. The experimental result showed that pre-heating treatment at 120 °C improves the efficiency and short-circuit current by about 28.4% and 19.1%, respectively. The conducted transient photovoltage measurements revealed that the increase of pre-heating temperatures leads to a longer electron lifetime and higher charge collection efficiency.

FEASIBILITY STUDY ON PREPARATION OF RICE STRAW NONWOVEN COATED WITH CHITOSAN FOR REACTIVE DYE ADSORPTION

Rice straw is the most abundant agricultural waste material in Thailand. Therefore, this research was interested in utilizing rice straw and adding value by preparing a reactive dye bioadsorbant. The aims of this research were to prepare rice straw nonwovens by the wet-laid process, study chitosan-coated nonwovens by the dip coating method, and evaluate the reactive dye adsorption capacity of the coated nonwovens. The ratio of weight per unit area of the prepared nonwovens was controlled. The nonwovens were dipped in chitosan solutions (0.5, 1, and 1.5 wt% of chitosan) to prepare chitosan coated nonwovens. Reactive dye adsorption capacity, chemical structure, morphology, and physical properties of the nonwovens were investigated. It was found that rice straw nonwoven coated with chitosan increased in thickness, hardness, and water resistance properties with increasing chitosan concentration. Chitosan-coated nonwoven, at 15% chitosan concentration and a contact time of 72 hours, was able to adsorb 38.40% of the reactive azo dye, C.I. Reactive Blue 194 (50 mg/L). The dye absorbency of the chitosan-coated nonwovens increased with the increase in the chitosan-coated concentration and the contact time. In addition, the chitosan-coated nonwovens could remain on rice straw cellulose nonwoven surfaces under reactive dye immersion for at least 72 hours without change. The results indicated that rice straw nonwovens coated with chitosan by the dip coating method had reactive dye adsorption abilities.

Comparative evaluation of various surface contaminants on the microleakage between 7th and 8th generation bonding agent: An in vitro study

To evaluate, the effect of, various surface contaminants on the microleakage between 7 Generation (G-Bond, GC) and 8 Generation Bonding Agent (G-Premio, GC). Ninety freshly extracted maxillary human premolars were collected for the study. They were randomly divided into two groups (n=45), Group 1-7 Generation and Group 2- 8 Generation. They were further subdivided into 3 sub-groups (n=15): a) Control b) Saliva c) Blood. A Class V cavity was prepared on the buccal surface. Samples of both the groups were applied with bonding agent and according to respective sub-group were contaminated with saliva and blood, before curing the bonding agent, then restored with Composite material. The samples were subjected to thermocycling and prepared for dye immersion. Samples were immersed in 2% Methylene Blue dye for 24 hours and later sectioned buccolingually. Each half of the buccolingually sectioned samples was observed under stereomicroscope under the power of 10x and 40x. Result was obtained using the Chi Square Test. In Group 1, minimum microleakage is observed in control group, and maximum in those contaminated with blood. In Group 2, maximum microleakage is observed in samples contaminated with blood and the microleakage in samples of control group and those contaminated with saliva is almost same and less than that observed in blood. 8 Generation shows better performance than 7 Generation Bonding Agent. Contamination from blood and saliva, during bonding leads to a grave outcome of microleakage, during restoration with composite. But, with newer generation of bonding agents, it seems to be a ray of hope at the dawn of preventing microleakage to quite an extent.

Synthesis of TiO2/ZnO photoanodes on FTO conductive glass for photovoltaic applications

For oxide semiconductors for application in dye-sensitized solar cells (DSSCs), titanium dioxide conjugated with zinc oxide thin films was synthesized and characterized. The UV (ultraviolet) spectrum characterization showed a peak of absorbance at around 355 nm, with a band gap of 3.25 eV and reflectance around 85%. Such characteristics allowed the fabrication of DSSCs with N719 dye, under simulated light of 100 mW/cm2. The highest efficiency of 1.17% was at 5% titanium dioxide and 4 h of dye immersion.

Vital dye immersion evaluations with juvenile delta smelt

AbstractImmersion‐based vital dyes were tested as a marking method for use in larval smelt mark–recapture studies. We assessed five fluorescent dyes as a mark for juvenile osmerids: 4‐Di‐1‐ASP, BODIPY FL C12, BODIPY 505/515, Nile red, and calcein. We marked juvenile Delta Smelt, Hypomesus transpacificus, as a proxy for Longfin Smelt, Spirinchus thaleichthys, to determine the efficacy of each as a batch marking technique for osmerids based on dye performance and survival. All groups of Delta Smelt including control groups exhibited high mortality (71%–100%, 5 days after trial), and lowest survival was observed in 4‐Di‐1‐ASP‐treated fish. Highest survival was observed in Nile red‐ and BODIPY FL C12‐treated fish. Fluorescence observations indicated that the brightest, visible fluorescence was seen in calcein and to a lesser extent, 4‐Di‐1‐ASP, followed by BODIPY FL C12 and Nile red. In addition to dye performance, it is recommended that immersion techniques that improve survival be considered.

Tensile Bond Strength and Marginal Integrity of a Self-adhering and a Self-etch Adhesive Flowable Composite after Artificial Thermomechanical Aging.

This study aims to compare the self-etch adhesive (SEA) and self-adhesive flowable composite (SAF) concerning tensile bond strength (TBS) and marginal integrity by microleakage (µ LK) test in deciduous molars after artificial thermomechanical aging. 120 extracted primary molars were collected. Sixty teeth were mounted for testing TBS. Teeth were restored using SAF (n = 30) and SEA-conventional flowable (CF) composite (n = 30) and subjected to artificial thermal aging. Half the teeth (n = 15) from each material were subjected to mechanical loading (SEA-TBS-L and SAF-TBS-L). The specimens with no-load (NL) served as control (SEA-TBS-NL and SAF-TBS-NL). Class V cavity prepared and restored with SAF (n = 30) and SEA-CF (n = 30) to test µ LK after thermal aging. The subgroups were as same as the TBS based on with or without mechanical loading (SEA-µ LK-L, SEA-µ LK-NL, SAF-µ LK-L, SAF-µ LK-L; n = 15 each). µ LK was determined by employing the dye immersion technique. Concerning TBS, there is a significant difference between SEA and SAF with load or no load. Concerning µ LK, there is a significant difference between the materials under loading and no difference was found when not mechanically loaded. Also, concerning both TBS and µ LK, a significant difference was observed between the load and no-load subgroups within each material. SAF exhibited higher TBS than the SEA. Mechanical loading not only adversely affected the TBS but also increased the µLK of the compared materials. Restoring the primary teeth with SAF not only shortens the laborious operatory time but also yields good clinical serviceability with the good bond strength and minimal µ LK, thus preventing premature loss of teeth and consequential malocclusion. Kamatchi M, Ajay R, Gawthaman M, et al. Tensile Bond Strength and Marginal Integrity of a Self-adhering and a Self-etch Adhesive Flowable Composite after Artificial Thermomechanical Aging. Int J Clin Pediatr Dent 2022;15(2):204-209.

Coactive impact of a novel multifunctional alum co-adsorbent for dye-sensitized solar cells DSSC

This study investigates how utilizing an environmentally friendly alum dye co-adsorbent impacts the overall performances of dye-sensitized solar cells (DSSCs). Various alum concentrations were added to anthocyanin-based blackberry dye solutions during the 24-hour dye immersion process. It was discovered that the alum dissolution process increased acidity, intensified the amount of hydroxyl group, and improved TiO2/dye interconnection through the effect of the Al(OH)3 mediator. As an added benefit, alum improved the purity of the dye solution by flocculating the crude impurities apart. Due to these multifunctional features, the photocurrent density (JSC) and the overall power conversion efficiency of the 6-ATDS cell have increased to 9.48 mA/cm−2 and 0.58%, respectively.

Study of electrophoretic deposition of ZnO photoanodes on fluorine-doped tin oxide (FTO) glass for dye-sensitized solar cells (DSSCs)

Semiconductors, such as zinc oxide (ZnO), are used in different scientific fields, including energy. This study applied ZnO thin films on a photovoltaic cell, specifically a dye-sensitized solar cell (DSSC). ZnO was used in solar cells due to its characteristics such as electronic mobility. Electrophoretic deposition (EPD) is an efficient method to deposit thin films since it can be done at room temperature and its parameters can be easily controlled. ZnO thin films were deposited on fluorine-doped tin oxide (FTO) glass, changing the tension parameter, and used in a DSSC, with different dye immersion times, between 7 and 24 h, to observe time effects on cell efficiency. For lower tension, 30 and 40 V, 7 h improved the cell efficiency, and at 50 V, 24 h favored the current density and efficiency. The highest efficiency was for the photoanode EPD deposited at 50 V, for 24 h dye immersion, at about 2.68%, and photocurrent of 13.55 mA/cm2.

Minimisation of pollution in the cotton fabric dyeing process with natural dyes by the selection of mordant type

PurposeThis paper aims to select a type of mordant from aluminium salts, namely, aluminium sulphate, aluminium nitrate and polyaluminium chloride (PAC) with the lowest potential for contamination so that their use will minimise pollution from natural dye waste. It also aims to determine the pollution value of natural dye immersion waste from jackfruit wood extract, secang wood, mangsi fruit and several synthetic dyes, to identify potential environmental pollution.Design/methodology/approachDyeing with natural dyes was performed by exhaust at room temperature by the pre-mordant method, while with synthetic dyes it was performed by exhaust according to the dyeing procedure (reactive, vat and naphthol). The groundwater, mordant solutions, natural dye extract and the waste-water from the natural and synthetic dyes were then tested to determine their biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), pH, Al and heavy metal contents such as chromium (Cr), copper (Cu), cadmium (Cd), nickel (Ni), cobalt (Co) and lead (Pb).FindingsAluminium sulphate had the lowest pollution load while PAC had the highest, as aluminium sulphate had a higher BOD5/COD ratio (0.62–0.67) than aluminium nitrate (0.56–0.64) or PAC (0.44–0.54). The dyeing waste from the three natural dyes contained an acidic pH of 3.5–4.2, Al of 75.280–621.34 mg/L, Cr of 0.154–0.215 mg/L and Cu of 0.035–0.072 mg/L. The values of TSS, COD and BOD5 are higher than the quality standards of the waste but are environmentally friendly because the ratio of the BOD5/COD values from the waste ranges from 0.44–0.67.Research limitations/implicationsThe findings indicate that as a mordant, aluminium sulphate results in lower pollution loads than aluminium nitrate and PAC. However, all three mordants contain Cr and Cu, albeit in negligible concentrations. Therefore, it is recommended that future studies strive to identify a mordant that has lower pollution loads and does not contain metals but can increase dyeing results to satisfy consumer requirements. It is the hope that, with the discovery of a new mordant, natural dyes will be the solution for the heavy metal pollution caused by synthetic dyes.Practical implicationsThe use of environmentally-friendly mordants and natural dyes in the Indonesian textile and batik industry will give rise to superior quality eco-textile and eco-batik products. Such environmentally-friendly and high-quality products will not only increase competition and consumer interest but increase product sales as well which will, in turn, increase incomes and the economy. Additionally, an increase in the use of natural dyes by the textile and batik industry will serve as additional income to the communities and farmers from which the raw materials for the natural dyes are sourced thereby creating jobs and increasing welfare.Social implicationsAs environmentally-friendly mordants and natural dyes replace the hazardous and toxic materials currently used in the textile and batik industry, it guarantees the health and safety of its consumers and workers. Furthermore, as the waste-water produced is biodegradable, it reduces river and groundwater pollution. It is, therefore, expected that this information will not only lead to a shift in attitude within the textile and batik industries but the adoption of environmentally-friendly materials, for the sake of the environment, as well as the development of eco-textile and eco-batik products.Originality/valueAluminium sulphate is a mordant type of aluminium salt with a lower potential for contamination than aluminium nitrate and PAC. However, PAC has been discovered to be a mordant for natural dyes, as has the fruit of the mangsi shrub, which has recently been discovered as a naturally occurring blue dye.

Abstract P747: Gpr68 Play a Protective Role in Ischemic Stroke in Mice

Introduction: Acidosis is one prevalent phenomenon in ischemic stroke. The literature has shown that protons directly gate acid-sensing ion channels (ASICs) and proton-activated chloride channel, both lead to neuronal injury However, it is unclear whether protons activate metabotropic pathways in brain neurons. There are four proton-sensitive G-protein coupled receptors (GPCRs): GPR4, GPR65, GPR68 and GPR132. It remains unknown whether any of these GPCRs mediate acid-induced signals in brain neurons or whether they contribute to ischemia-induced brain injury. Methods: Total RNA from human cortical tissue or mouse brain was isolated using TRIzol and an RNase Kit. Standard RT-PCR was performed to determine the expression of these GPCRs in the brain. An in vitro slice injury model was used for functional screening. To determine the effect of ischemia, WT and knockout male mice were subjected to MCAO. To study brain injury, brains were sectioned coronally at 1 mm intervals and stained by vital dye immersion: (2%) 2,3,5-triphenyltetrazolium hydrochloride (TTC). Locomotor analysis and corner test were used to assess behavior outcome. Adeno-associated virus (AAV) -mediated gene delivery was used to determine the outcome of GPR68 overexpression. Results: RT-PCR showed that brain tissue expressed GPR4, -65, and -68. The expression of GPR68 was evident at 30 cycles. In organotypic slices, compared to the WT, deleting GPR4 or GPR65 had no effect while deleting GPR68 significantly increased acidosis-induced neuronal injury. At both 24 hour and 72 hour after 45 minutes MCAO, GPR68 deletion increased brain injury (p=0.0020 for 24hour, p=0.0392 for 72hour, Mann-Whitney U test). WT and GPR68-/- mice did not differ in baseline locomotor activities or corner test. On the third day following MCAO, GPR68-/- exhibited significantly more left rotations (p=0.0287, Mann-Whitney U test) than WT animals. Lastly, mice receiving AAV-GPR68 exhibited an average infarct of 21.97 ± 12.4%, significantly (p = 0.0022, Mann-Whitney U test) smaller than those receiving AAV-GFP (37.2 ± 6.8%). Conclusion: These data showed that GPR68 functions as a neuroprotective proton receptor in the brain.

Microleakage Assessment of Two Different Pit and Fissure Sealants: A Comparative Confocal Laser Scanning Microscopy Study.

IntroductionPit and fissures of permanent dentition are considered to be highly vulnerable to the adhesion of cariogenic microorganisms and consequently result in caries formation. The main problem associated with sealant failure will be microleakage. Therefore, sealants can be considered to be an effective preventive procedure for dental caries, only if it strongly bonds to the tooth, and protect the pit and fissures from the oral bacterial environment.Aim and objectiveTo compare and assess the microleakage of two different pit and fissure sealants on permanent molars.Materials and methodsA total of 20 extracted third molars were randomly divided into two groups where group I is conventional sealant and group II is hydrophilic sealant. Occlusal surfaces of permanent molars were treated with 37% orthophosphoric acid before sealant placement. Tooth samples were subjected to 0.1% rhodamine dye immersion, thermocycling, and tooth samples were sectioned and evaluated under a confocal laser microscope for dye penetration. A non-parametric test (Mann–Whitney U) was performed to compare the mean microleakage score difference between the groups.ResultsGroup II (hydrophilic sealant) showed a minimum level of the microleakage score when compared to group I (conventional sealant) and was found to be statistically significant using the Mann-Whitney U test with a p value <0.05.ConclusionThe less the microleakage, the better will be the retention of the sealant for a longer duration and cariostatic action.How to cite this articlePrabakar J, Indiran MA, Kumar P, et al. Microleakage Assessment of Two Different Pit and Fissure Sealants: A Comparative Confocal Laser Scanning Microscopy Study. Int J Clin Pediatr Dent 2020;13(S-1):S29–S33.

Novel and effective disposable device that provides 2-way protection to the duodenoscope from microbial contamination

Duodenoscope contamination is associated with notable patient morbidity and mortality and can occur despite high-level disinfection protocols, requiring a solution that protects against contamination of the endoscope in the first place. We assessed a newly cleared, single-use device to seal the distal end of duodenoscopes while preserving optics and other endoscope functionality and tested its ability to protect against contamination using dye immersion tests and microbial inoculation. Dye immersion tests revealed a complete seal with no leakage. Rigorous microbial challenge tests showed the device can both protect against contamination of the endoscope by external microbes ("outside-in" protection) and shield instruments from contact with pre-existing microbial biofilm on or around the elevator that may have survived reprocessing ("inside-out" protection). Optical and mechanical performance of the endoscope was not compromised by the addition of the device. The results show that this disposable device provides 2-way protection to the duodenoscope from microbial contamination, without the potential for disrupting current equipment, technique, and workflow.

An In-vitro Study to Determine the Sealing Ability of Biodentine when used as a Class II Restorative Material

Introduction: Microleakage is a major setback to restorative dentistry. Leakage at the tooth/restoration interface may lead to numerous problems like postoperative sensitivity, recurrent caries, marginal sealing and later total failure of restoration. Aim: To determine the sealing ability (microleakage) of a new hydraulic calcium silicate cement (Biodentine) as a base material and a bulk filling material. Materials and Methods: An in-vitro study was conducted with ten freshly extracted maxillary molars from March 2019 to June 2019. Standardised Class II cavities were prepared on mesial and distal proximal surfaces. The twenty prepared samples were randomly divided into two groups (n=10)- G1 (BiodentineTM group) and G2 (BiodentineTM + Tetric N-Ceram group). The samples were subjected to thermocycling, followed by 1% methylene blue dye immersion. They were subsequently sectioned both buccolingually and mesiodistally in order to separate to proximal restorations (mesial and distal) and appreciate the amount of dye penetration at tooth/restoration interface respectively. Microleakage was evaluated by observing the samples under a stereomicroscope (30x). The data obtained was analysed using one-way ANOVA test and compared using Post-hoc test. p-value &lt;0.05 to be considered significant. Results: Biodentine showed no significant difference between the sealing ability as a bulk filling and a base material. Group G2 (0.35) indicated comparatively less microleakage as compared to Group G1 (0.6) but the difference in microleakages in both groups was insignificant (p-value 0.083467). Conclusion: BiodentineTM exhibits microleakage when used as a bulk filling material and as a dentin substitute in Class II cavities since there is no significant difference in both the groups.

Influence of a Bleaching Agent on the Color Stability of Indirect Composite Resins Immersed in Dyes

This study aimed to evaluate the effect of a bleaching agent on the color of extrinsically pigmented indirect composite resins. Samples of five resins (Adoro, Resilab, Cristobal, Sinfony, Epricord) were manufactured and divided into five groups: red wine, coffee, orange juice, Coca-Cola, and artificial saliva (control). The stained samples were immersed in a 38% hydrogen peroxide solution for 30 min per week, over three weeks. Color readings were performed at the initial state (L0), after 21 days of dye immersion (ΔE1, L1), and after 7 (ΔE2, L2), 14 (ΔE3, L3), and 21 days (ΔE4, L4) of bleach immersion. Data were subjected to ANOVA and Tukey’s honestly significant difference (HSD) test (α = 0.05). The color alteration was greater in ΔE1, regardless of color solution, indicating extrinsic pigmentation. The Resilab group exhibited greater ΔE1 values than the other resins. The bleaching agent promoted bleaching action on the surfaces of the materials studied, removing the previously impregnated pigments.

Relevance of wood anatomy and size of Amazonian trees in the determination and allometry of sapwood area

ABSTRACT Hydrological processes in forest stands are mainly influenced by tree species composition and morpho-physiological characteristics. Few studies on anatomical patterns that govern plant hydraulics were conducted in tropical forest ecosystems. Thus, we used dye immersion to analyze sapwood area patterns of 34 trees belonging to 26 species from a terra firme forest in the central Brazilian Amazon. The sapwood area was related with wood anatomy and tree size parameters (diameter-at-breast-height - DBH, total height and estimated whole-tree volume). Exponential allometric equations were used to model sapwood area using the biometrical variables measured. Sapwood area traits (cross-section non-uniformity and heartwood visibility) varied significantly among and within species even though all were classified as diffuse porous. DBH was strongly and non-linearly correlated with sapwood area (R 2 = 0.46, P &lt; 0.001), while no correlation was observed with vessel-lumen diameter (P = 0.94) and frequency (P = 0.58). Sapwood area and shape were also affected by the occurrence of vessel obstruction (i.e., tyloses), hollow stems and diseases. Our results suggest that sapwood area patterns and correlated variables are driven by intrinsic species characteristics, microclimate and ecological succession within the stand. We believe that individual tree sapwood characteristics have strong implications over water use, hydrological stand upsaling and biomass quantification. These characteristics should be taken into account (e.g., through a multi-point sampling approach) when estimating forest stand transpiration in a highly biodiverse ecosystem.

Performance of Pterocarpus Indicus Willd Leaf Extract as Natural Dye TiO2-Dye/ITO DSSC

Abstract The search of sensitizers of natural dye for a solar cell has been intensively studied. One of the potentials as dye source is Pterocarpus Indicus Willd, PIW (L.) plant. The use of PIW extract dye for dye-sensitized solar cell (DSSC) application has rarely found in the literature. Such natural chlorophyll or flavonoid membrane could be used as mesoporous tissue in DSSC. It makes chlorophyll pigment attractive to be used as a sensitizer in solar cells. The natural dyes have been used with the combination of the metal oxide semiconductor to improve the DSSC performance. We used TiO2 as a working electrode due to its high thermal stability, non-toxic, low fabrication cost, and excellent optical properties. The primary objective is to obtain the structure, absorbance, and efficiency using dye concentration of immersion under of 12, 15, and 18 hours. We used chlorophyll extract of PIW leaves to soak the film composite TiO2/ITO with a variation of dye immersion time. Method for deposition of film TiO2 was a slip casting and followed by heating at 500 oC for 1 hour. The counter electrode was the same structure with firstly been coated with carbon material on the conducting plane and drips using electrolyte. Both symmetric structures then taped together using a transparent flexible keyboard protector. The SEM analyses show that the more extended soaking of TiO2 surface dye becomes entirely dissolved by the dye solution. The UV-Vis characterization revealed that a 15 hours dye immersion time is resulting in the optimum absorbance. The highest result of I-V characterization is 12 hours immersion with a light intensity of 150 mW/cm2. The DSSC parameters obtained are Jsc of 0.370817 mA/cm2, Voc of 0.400197 V and Efficiency equal to 0.035%. These results tell us that PIW chlorophyll extract has a potential for DSSC application.

Evaluation of surface roughness and color change of bovine enamel after immersion in dye solution

Aim: The aim of this in vitro study was to evaluate the influence of dye solution on enamel color change after bleaching protocols and the effectiveness in maintaining the color of these agents.Material and Methods: The buccal surfaces of sixty-five bovine incisors were cleaned and polished, and the enamel specimens were divided into thirteen groups: G1 to G6: treated with 6% hydrogen peroxide using different surface agents; G7 to G12: treated with 15% hydrogen peroxide using different surface agents; G13: control. After 24 hours, the groups treated were immersed in black tea solution; the control group was stored in artificial saliva. The color was evaluated prior to bleaching, 24 hours later and after immersion in the dye solution; the roughness was measured immediately after bleaching, 24 hours later and 7 days after immersion in the dye solution. The data was analyzed using the Kruskal-Wallis test, followed by the Miller test for roughness analysis, and the Duncan test for color change analysis. It was used 5% significant level with p&lt;0.05.Results: The data found in the evaluation of surface roughness after bleaching indicated a reduction of roughness in all the groups. The surface agent Bifluoride, when applied, showed an increase in roughness after its application and it decreases after immersion in dye solution; the surface agent Desensibilize and the XP Bond adhesive showed greater color alteration after immersion in dye solution.Conclusions: All the groups studied, under different whitening technique, were effective in promoting whitening.

Charge Transfer Dynamics of Highly Efficient Cyanidin-3-O- Glucoside Sensitizer for Dye-Sensitized Solar Cells

This paper reports the novel efficiency achievement of black rice-based natural dye- sensitized solar cells. The higher dye concentration, the longer dye extraction as well as dye immersion onto a TiO2 film, and the co-adsorption addition are key strategies for improved-cell performance compared to the highest previous achievement. The black rice dye containing 1.38 mM cyanidin-3-O-glucoside has been extracted without purification for 3 weeks at dark condition and room temperature. The anatase TiO2 photoanode was dipped into dye solution within 4 days. Its electrode was firmly sealed to be a cell and was filled by I-/I3- electrolyte using vacuum technique. As a result, the overall solar-to-energy conversion efficiency was 1.49% at AM 1.5 illumination (100 mW.cm-2). The voltametric analysis has reported the interfacial electronic band edges of TiO2-Dye-Electrolyte. Furthermore, electrochemical impedance spectroscopy has shown the kinetic of interfacial electron transfer dynamics among TiO2-dye-electrolyte. The cell has the transfer resistance (Rt) of 12.5 ω, the recombination resistance (Rr) of 266.8 ω, effective electron diffusion coefficients (Dn) of 1.4 × 10-3 cm2/s, Dye-TiO2 effective electron transfer (τd) of 26.6 μs, effective diffusion length (Ln)of 33.78 μm, chemical capacitance (Cμ) of 12.43 μF, and electron lifetime (τn) of 3.32 ms.

Intraoperative Fluorescein Staining of Cryopreserved Amniotic Membrane Grafts to Improve Visualization During and After Pterygium Surgery: A Novel Technique.

To describe a new method of enhancing the visualization of amniotic membrane grafts with fluorescein staining during pterygium surgery. Pterygium excision surgery using intraoperatively stained cryopreserved amniotic membranes was performed on 346 eyes. A sterile 0.6 mg sodium fluorescein strip was placed directly onto the amniotic membrane in the manufacturer's original packaging, and the stained allograft was then transplanted onto the planned site. Staining intensities, at 3, 5, and 10 minutes of dye immersion, were compared. Immediate postoperative pain rating (scale 0-10), visibility of the fluorescein-stained amniotic membrane graft, and conjunctival autograft and amniotic membrane graft elevation, dehiscence, retraction, or displacement were recorded. The recurrence rate of the study population was compared with that of a previous cohort of 121 patients who underwent pterygium excision with conjunctival autograft without stained amniotic membrane. Direct contact of the fluorescein strip on the amniotic membrane at 3, 5, and 10 minutes showed no differences in subjective staining intensity. Fluorescein-stained amniotic membrane was easily detected on the ocular surface during and 24 hours after pterygium surgery. The average immediate postoperative pain rating was 0.8 ± 1.8. No intraoperative complications or postoperative amniotic membrane graft dehiscence, retraction, or displacement occurred. The recurrence rate using fluorescein-stained amniotic membrane (3 patients, 0.9%, mean follow-up time 31.8 ± 18.6 weeks) did not differ from that of the previous cohort without the stained amniotic membrane (2.5%; χ(1) = 1.837, P = 0.183). Fluorescein strip staining of the amniotic membrane is a novel and safe intraoperative method to enhance visualization and handling of the graft during and after ocular surgeries.