Effect of light and heat on bleaching action of hydrogen peroxide

This study aimed to verify the effect of light and heat on bleaching action of 40% hydrogen peroxide (Opalescence Boost PF – Ultradent, BR). Thirty-three bovine incisors were submitted to in-office dental bleaching and divided into three groups (n=11): CO group – control, no light or heat; CA group – heat with a hairdryer; LC group – light and heat with a photoactivation device. For this, a gingival barrier (OpalDam – Ultradent, SP, BR) isolated a circular area around the flatter region of the crown. Afterwards, the bleaching gel was applied for 15 minutes and repeated twice, totaling 45 minutes of application. For the CA and LC groups, the heat source was maintained during the application of the bleaching gel. Temperature was standardized in 5°C for both groups and monitored using a thermocouple inserted into the pulp chamber. The color measurement was performed before and after bleaching using a spectrophotometer. The inner margin of the isolated area of each dental crown was equivalent to the tip of the spectrophotometer (4 mm). Color change was verified by CIEDE2000 system (ΔE00). One way ANOVA and Tukey's test were used to analyze data (p-values set to 5%). The values of ΔE00 were equal for LC (2,66±0,29) and CA (2,44±0,88), and both were higher than CO (1,31±0,37). Therefore, light does not play a fundamental role for in-office dental bleaching. Same dental bleaching outcomes are obtained using different heat sources.

Agar Extraction, Physical Properties, FTIR Analysis and Biochemical Composition of Three Edible Species of Red Seaweeds Gracilaria corticata (J. Agardh), Gracilaria dentata (J. Agardh) and Gracilariopsis longissima (S. G. Gmelin)........

Three species of red algae Gracilaria corticata (J. Agardh), Gracilaria dentata (J. Agardh) and Gracilariopsis longissima (S.G. Gmelin), Steentoft, L. M; Irvine and Farnham (formerly Gracilaria verrucosa (Hudson) were collected from four different sites (Buleji, Hawks Bay, Manora and Paradise Point) of Karachi coast. The G. corticata was the dominant species and the highest yield of agar was compared to other studied species. The physical properties such as gel temperature, melting temperature, density, viscosity and gel strength showed large variations. Interestingly, the gel temperature, melting temperature, density, and gel strength had the highest value in G. corticata samples collected, while gel viscosity recorded the highest value in G. dentata samples. Intensive spectroscopic FTIR analysis was determined in all three species of G. corticata, G. dentata and G. longissima. The bands at 414.7/cm to 3917.2/cm represents stretching and bending vibrations of alcohol O-H, amine N-H, alkane C-H, alkyne C=C, nitriles C=N, carboxyl C=O, nitro aromatic N=O, alkane C-C, nitro methane C-N, aliphatic amines C-N, sulfoxides S=O, alkene C-H alkyl halide C-Cl, C-I groups. The ash content of all studied species (G. corticata, G. dentata and G. longissima) was in the range of 20-30%, while the carbohydrate content was in the range of 22-24%. The results of this study suggested the utilization of our natural resources present in Karachi coast. This could be achieved by determining the quantity and quality of agar in the edible species of Gracilaria/Gracilariopsis.

Formulation of Chitosan-Ethylenediaminetetraacetic Acid/Poloxamer Gel Containing Fruit’s Hull of Garcinia mangostana Extract

The purpose of this study was to develop the formulation of chitosan-ethylenediaminetetraacetic acid (EDTA)/poloxamer containing GM extract gel. The GM extract with a concentration of 0.5% wt was incorporated into a gel formulation. The physical appearance, pH, viscosity and percentage label amount of GM extract gel were performed. The in vitro antioxidant activity of gel were evaluated using (2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The antibacterial activity against Staphylococcus aureus was evaluated by the zone of inhibition method. The mucoadhesive property was investigated using viscosity technique. The results illustrate that the chitosan-EDTA/poloxamer containing GM extract gel had a yellow colour of GM extract. The pH of a gel was in the range of 4.47 – 6.87. The percentage label amount of gel was in the range of 98.71 – 99.37% and the viscosity of gel were in the range of 14767 – 14784 mPa/s and 9607 – 9641 mPa/s. The TSol-Gel temperature was 35 oC. The antioxidant activities (IC50) which evaluated by DPPH method of all gel was in the range of 13.20 – 13.57 mg/ml. The zone of inhibition of gel against S.aureus was in the range of 8.17 – 10.52 mm. The chitosan-EDTA may improve the mucoadhesive property of gel. In conclusion, the chitosan-EDTA/poloxamer containing GM extract gel may have the potential for pharmaceutical and wound healing application.

THE EFFECT OF SOL-GEL TEMPERATURE AND SOLVENT POLYETHYLENE GLYCOL (PEG) IN ZnO- TiO2 PHOTOCATALYST ACT AS DEGRADER OF TEXTILE DYEING LIQUID WASTE

<p>The use of TiO₂ powder as photocatalyst still provides some disadvantages such as the difficulties in regenerate ion, the low adsorption and turbulence . These problems can be overcomed by providing the photocatalyst as a composite of ZnO-TiO2. This research aims to investigate the effect of composition of solvent and temperatureof synthesis on the quality and photocatalytic activity of ZnO-TiO2 which was prepared by sol-gel method. The photocatalytic activity was determined by applying the composite in degradation of Procion Red MX-8B under irradition of UV light for 24 hours. The procion red concentration after degradation was determined by UV-Vis spectrophotometer. Meanwhile the effect of synt hesis temperature on crystal structure of composite was studied by XRD. The results show that the composite which was prepared by PEG 1500 at 1:4 of moles ratio and at 70 °C of synthesis temperature has highest degradation percentage, i.e. 55.375 % and photocataltic activity of 3.561 x 10^-7mg/cm²s.</p>

THE EFFECT OF SOL-GEL TEMPERATURE AND SOLVENT POLYETHYLENE GLYCOL (PEG) IN ZnO- TiO2 PHOTOCATALYST ACT AS DEGRADER OF TEXTILE DYEING LIQUID WASTE

<p>The use of TiO₂ powder as photocatalyst still provides some disadvantages such as the difficulties in regenerate ion, the low adsorption and turbulence . These problems can be overcomed by providing the photocatalyst as a composite of ZnO-TiO2. This research aims to investigate the effect of composition of solvent and temperatureof synthesis on the quality and photocatalytic activity of ZnO-TiO2 which was prepared by sol-gel method. The photocatalytic activity was determined by applying the composite in degradation of Procion Red MX-8B under irradition of UV light for 24 hours. The procion red concentration after degradation was determined by UV-Vis spectrophotometer. Meanwhile the effect of synt hesis temperature on crystal structure of composite was studied by XRD. The results show that the composite which was prepared by PEG 1500 at 1:4 of moles ratio and at 70 °C of synthesis temperature has highest degradation percentage, i.e. 55.375 % and photocataltic activity of 3.561 x 10^-7mg/cm²s.</p>

Synthesis and Characterization of Zeolite Y From Bagasse Ash with Hydrothermal Temperatures Variations Using The Sol-Gel Method

<p class="Abstract">Zeolite Synthesis Y is done using sol-gel method on the molar composition of 10Na₂O: 15 SiO₂: x Al₂O₃: 300 H₂O with Si/Al on ratio of 2,43 and hydrothermal temperatures variations of 60, 80 and 100 °C. Characterization includes XRD to discover crystallinity and the purity of zeolite, FTIR for the analysis of functional groups and of the surface width with the adsorption of methylene blue. XRD result shows that the formed zeolites Y is still mixed with zeolite P, the best result in synthesis with hydrothermal temperatures of 80 °C. FTIR analysis showsthat all zeolite synthesis contain a common functionO-Si-O/O-Al-O and double ring. The surface area of zeolite Y at 60, 80 and 100 °C is 22,5522; 23,0603 and22,9898m²/gram.<strong></strong></p><p class="BodyAbstract"><strong> </strong></p><p class="BodyAbstract"><em><strong>Keywords</strong><strong>:</strong> Bagasse, sol-gel, temperature hydrothermal, zeolite Y</em></p>

Development of In Situ Gel for Oral Application

In situ gel, a new concept of medical product for oral applications was developed using Poloxamer 407 (P) and Carbopol 934 (C) which are thermo-and pH-sensitive sol-gel polymers, respectively. The formulations were evaluated for the physical appearance, pH, viscosity, sol-gel temperature, gel strength and buccal mucoadhesive (adhesion to porcine buccal mucosa). Benzalkonium chloride (BzCl) 0.1% w/v was added in the suitable formulations as a model drug. Formulations containing 20% P (pH = 7.1) and 20% P + 0.6% C (pH = 5.0) showed good physical appearances which turned to gels in buccal conditions. Their mucoadhesive force to porcine buccal mucosa were higher than formulations containing 10 and 15 % P(p<0.05). The present of 0.6 % C in the formulation did not affect gel strength but tended to increase mucoadhesive properties. The release of BzCl from the formulations was performed using Franz diffusion cell at 37°C for 1 hour. There were no different in drug release from both formulations(p<0.05), the amount of drug release was 11.7% ± 4.4 and 10.9% ± 0.8, respectively. In conclusion, formulation containing 20% P and 0.6% C has revealed the most suitable properties as in situ gel for buccal mucosa applications, the release of BzCl was 10.9% ± 0.8 within 1 hour.