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Sample records for bleaching agents activated

  1. In vitro penetration of bleaching agents into the pulp chamber

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Valera, M C; Mancini, M N G

    2004-01-01

    To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures.......To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures....

  2. REMINERALIZATION POTENTIAL OF A CARBAMIDE BLEACHING AGENT

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    Marinova-Takorova Borislavova Mirela

    2016-03-01

    Full Text Available Background: Bleaching has gradually became a popular procedure for people searching for aesthetic improvement. The aim of this in vitro study was to investigate the effect of bleaching with 45% carbamide peroxide on the level of mineralization of enamel, using laser fluorescence. Materials and methods: Sixty extracted human teeth were treated with 45% carbamid peroxide (Opalescence, Ultradent, 4 consecutive days for one hour each day. The effect of the bleaching agent on the level of mineralization of enamel was measured with DIAGNO dent pen. The statistical method we use was descriptive analysis. Results: The average values, measured before the applications of the carbamid peroxide were 6.33. On the first day they were 5.41, on the second 5.38, on the third 5.11 and 5.35 on the forth. Conclusion: There was observed a slight remineralization effect due to the incorporated Ca2+ and F- ions in the bleaching agent that we have used.

  3. The effect of two bleaching agents on the phosphate concentration of the enamel evaluated by Raman spectroscopy: An ex vivo study

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    Sokkalingam Mothilal Venkatesan

    2012-01-01

    Full Text Available Aim : The aim of this ex vivo study was to evaluate the effect of in-office bleaching agents,-35% and 38% hydrogen peroxide containing bleaching agents, on the phosphate concentration of the enamel evaluated by Raman spectroscopy. Materials and Methods : Forty noncarious, craze-free human maxillary incisors, extracted for periodontal reasons, were used in this study. Baseline Raman spectra from each specimen were obtained before the application of the bleaching agent to assess the phosphate content present in the teeth. The teeth were divided into two groups: Group A - bleached with pola office bleach (35% hydrogen peroxide, potassium nitrate (light activated. Group B - bleached with opalescence Xtra bleach (38% hydrogen peroxide potassium nitrate and fluoride (chemical activated. After the bleaching procedure, the treated specimens were taken to obtain Raman spectra to assess the phosphate loss after bleaching treatment. Results : The results showed that the chemically activated bleaching agent showed less phosphate loss when compared with the light activated bleaching agent. Conclusion : Within the limitations of this study, it can be concluded that the chemically activated bleaching agent showed minimal phosphate loss when compared to light activated bleaching agent. The chemically activated bleaching agent was better than the light activated bleaching agent when values were evaluated statistically.

  4. Short communication: The influence of solids concentration and bleaching agent on bleaching efficacy and flavor of sweet whey powder.

    Science.gov (United States)

    Jervis, M G; Smith, T J; Drake, M A

    2015-04-01

    Recent studies have demonstrated the effect of bleaching conditions and bleaching agent on flavor and functional properties of whey protein ingredients. Solids concentration at bleaching significantly affected bleaching efficacy and flavor effects of different bleaching agents. It is not known if these parameters influence quality of sweet whey powder (SWP). The purpose of this study was to determine the effects of solids concentration and bleaching agent on the flavor and bleaching efficacy of SWP. Colored cheddar whey was manufactured, fat separated, and pasteurized. Subsequently, the whey (6.7% solids) was bleached, concentrated using reverse osmosis (RO) to 14% solids, and then spray dried, or whey was concentrated before bleaching and then spray dried. Bleaching treatments included a control (no bleaching, 50 °C, 60 min), hydrogen peroxide (HP; 250 mg/kg, 50 °C, 60 min), benzoyl peroxide (50 mg/kg, 50 °C, 60 min), lactoperoxidase (20 mg/kg of HP, 50 °C, 30 min), and external peroxidase (MaxiBright, DSM Food Specialties, Delft, the Netherlands; 2 dairy bleaching units/mL, 50 °C, 30 min). The experiment was repeated in triplicate. Sensory properties and volatile compounds of SWP were evaluated by a trained panel and gas chromatography-mass spectrometry, respectively. Bleaching efficacy (norbixin destruction) and benzoic acid were measured by HPLC. Differences in bleaching efficacy, sensory and volatile compound profiles, and benzoic acid were observed with different bleaching agents, consistent with previous studies. Solids concentration affected bleaching efficacy of HP, but not other bleaching agents. The SWP from whey bleached with HP or lactoperoxidase following RO had increased cardboard and fatty flavors and higher concentrations of lipid oxidation compounds compared with SWP from whey bleached before RO. The SWP bleached with benzoyl peroxide after RO contained less benzoic acid than SWP from whey bleached before RO. These results indicate that

  5. Effect of temperature and bleaching agent on bleaching of liquid Cheddar whey.

    Science.gov (United States)

    Listiyani, M A D; Campbell, R E; Miracle, R E; Barbano, D M; Gerard, P D; Drake, M A

    2012-01-01

    The use of whey protein as an ingredient in foods and beverages is increasing, and thus demand for colorless and mild-tasting whey protein is rising. Bleaching is commonly applied to fluid colored cheese whey to decrease color, and different temperatures and bleach concentrations are used. The objectives of this study were to compare the effects of hot and cold bleaching, the point of bleaching (before or after fat separation), and bleaching agent on bleaching efficacy and volatile components of liquid colored and uncolored Cheddar whey. First, Cheddar whey was manufactured, pasteurized, fat-separated, and subjected to one of a number of hot (68°C) or cold (4°C) bleaching applications [hydrogen peroxide (HP) 50 to 500 mg/kg; benzoyl peroxide (BP) 25 to 100 mg/kg] followed by measurement of residual norbixin and color by reflectance. Bleaching agent concentrations were then selected for the second trial. Liquid colored Cheddar whey was manufactured in triplicate and pasteurized. Part of the whey was collected (no separation, NSE) and the rest was subjected to fat separation (FSE). The NSE and FSE wheys were then subdivided and bleaching treatments (BP 50 or 100 mg/kg and HP 250 or 500 mg/kg) at 68°C for 30 min or 4°C for 16 h were applied. Control NSE and FSE with no added bleach were also subjected to each time-temperature combination. Volatile compounds from wheys were evaluated by gas chromatography-mass spectrometry, and norbixin (annatto) was extracted and quantified to compare bleaching efficacy. Proximate analysis, including total solids, protein, and fat contents, was also conducted. Liquid whey subjected to hot bleaching at both concentrations of HP or at 100mg/kg BP had greater lipid oxidation products (aldehydes) compared with unbleached wheys, 50mg/kg BP hot-bleached whey, or cold-bleached wheys. No effect was detected between NSE and FSE liquid Cheddar whey on the relative abundance of volatile lipid oxidation products. Wheys bleached with BP had

  6. Ion release from a composite resin after exposure to different 10% carbamide peroxide bleaching agents

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    Renata Plá Rizzolo Bueno

    2012-06-01

    Full Text Available OBJECTIVE: This in vitro study evaluated the influence of two 10% carbamide peroxide bleaching agents - a commercial product (Opalescence PF; Ultradent Products, Inc. and a bleaching agent prepared in a compounding pharmacy - on the chemical degradation of a light-activated composite resin by determining its release of ions before and after exposure to the agents. MATERIAL AND METHODS: Thirty composite resin (Filtek Z250; 3M/ESPE samples were divided into three groups: group I (exposed to Opalescence PF commercial bleaching agent, group II (exposed to a compounded bleaching agent and group III (control - Milli-Q water. After 14 days of exposure, with a protocol of 8 h of daily exposure to the bleaching agents and 16 h of immersion in Milli-Q water, the analysis of ion release was carried out using a HP 8453 spectrophotometer. The values were analyzed statistically by ANOVA, Tukey's test and the paired t-tests. The significance level was set at 5%. RESULTS: After 14 days of the experiment, statistically significant difference was found between group II and groups I and III, with greater ion release from the composite resin in group II. CONCLUSIONS: The compounded bleaching agent had a more aggressive effect on the composite resin after 14 days of exposure than the commercial product and the control (no bleaching.

  7. Intrapulpal temperature variation during bleaching with various activation mechanisms

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    Sílvia Masae de Araujo Michida

    2009-10-01

    Full Text Available OBJECTIVES: The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35% hydrogen peroxide using different sources of activation. MATERIAL AND METHODS: Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12: (G1 Control - Bleaching gel without light activation, (G2 Bleaching gel + halogen light, (G3 Bleaching gel + LED, (G4 Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (a=0.05. RESULTS: The mean intrapulpal temperature values (ºC in the groups were: G1: 0.617 ± 0.41; G2: 1.800 ± 0.68; G3: 0.975 ± 0.51; and G4: 4.325 ± 1.09. The mean maximum temperature variation (MTV values were: 1.5ºC (G1, 2.9ºC (G2, 1.7ºC (G3 and 6.9ºC (G4. When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05, but G2 and G4 presented significantly higher (p<0.05 intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05 from each other. CONCLUSIONS: The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.

  8. Effectiveness of bleaching agent on composite resin discoloration

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    Galih Sampoerno

    2012-03-01

    Full Text Available Background: The discoloration of teeth, especially anterior teeth, is one of aesthetic problems. The use of tooth bleaching agents for discolored natural teeth is becoming increasingly popular. Many dentists, however, get many problems when they conduct bleaching process since there is much composite filling on patient’s anterior teeth. Although many research have focused on the discoloration of composite resin after bleaching process, the problem still becomes debatable. Purpose: The purpose of this study was to investigate the difference of the discoloration between hybrid composite and nano composite before and after the application of tooth bleaching agent, 38% hydrogen peroxide. Methods: Eighteen disk-shaped specimens (5 mm of each of two composite resins, hybrid and nano filler, were prepared. The each group was treated 3 times and the specimens were divided into two groups consisted of 9 specimens for each, and then immersed in black tea solutions for 72 hours. Next, after having staining and bleaching processes, the color of the specimens was measured with a optic spectrophotometer by using photo with type BPY-47 and digital microvolt. The differences of the light intensity among three measurements were then calculated. Afterwards, GLM MANOVA Repeated Measure and parametric analysis (Independent t-test and Paired t-test were then used to analyze the data. Results: After staining process, it is then known that the nano composite had more discoloration and more affected by the black tea solution than the hybrid one. Conclusion: After bleaching, the discoloration was finally removed completely from both hybride and nano filler composite resins and became brighter from the baseline color.Latar belakang: Salah satu problem estetik adalah adanya perubahan warna pada gigi anterior. Peningkatan pemakaian bahan bleaching semakin popular. Banyak dokter gigi mempunyai problem ketika mereka akan melakukan proses bleaching dan ditemukan banyak

  9. Comparative study of the effects of two bleaching agents on oral microbiota.

    Science.gov (United States)

    Alkmin, Yara Tardelli; Sartorelli, Renata; Flório, Flávia Martão; Basting, Roberta Tarkany

    2005-01-01

    This study evaluated the in vivo effects of bleaching agents containing 10% carbamide peroxide (Platinum/Colgate) or 7.5% hydrogen peroxide (Day White 2Z/Discus Dental) on mutans Streptococcus during dental bleaching. The products were applied on 30 volunteers who needed dental bleaching. In each volunteer, one of the two bleaching agents was used on both dental arches one hour a day for three weeks. Analysis of the bacterial counts was made by collecting saliva before (baseline values), during (7 and 21 days) bleaching treatments and 14 days posttreatment. The Friedman non-parametric analysis (alpha=0.05) found no differences in microorganism counts at different times for each group for both agents (p>0.05). The Mann Whitney nonparametric test (alpha=0.05) showed no differences in micro-organism counts for both agents (p>0.05). Different bleaching agents did not change the oral cavity mutans Streptococcus counts.

  10. Susceptibility of Enamel Treated with Bleaching Agents to Mineral Loss after Cariogenic Challenge

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    Hüseyin Tezel

    2011-01-01

    Full Text Available Objectives. Controversial reports exist whether bleaching agents cause a susceptibility to demineralization. The aim of this study was to compare the calcium loss of enamel treated with different bleaching agents and activation methods. Method and Materials. The specimens obtained from human premolars were treated in accordance with manufacturer protocols; 10% carbamide peroxide, 38% hydrogen peroxide light-activated, 38% hydrogen peroxide laser-activated, and no treatment (control. After cariogenic challenge calcium concentrations were determined by Inductively Coupled Plasma Mass Spectrometry. Results. No differences were found between the calcium loss of the laser-activated group and 10% carbamide peroxide group (>0.05. However, the differences between laser-activated and control groups were statistically significant (0.05. On the other hand, the light-activated group showed a significantly higher calcium loss compared with the other groups (<0.05. Conclusions. The results show that bleaching agents may cause calcium loss but it seems to be a negligible quantity for clinical aspects.

  11. Influence of fluoride-containing adhesives and bleaching agents on enamel bond strength

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    Vanessa Cavalli

    2012-12-01

    Full Text Available This study evaluated the influence of fluoride-containing carbamide peroxide (CP bleaching agents and adhesive systems on bonded enamel interfaces that are part of the dynamic pH cycling and thermal cycling models. The buccal surfaces of 60 bovine incisors were restored with a composite resin and bonded with three- and two-step, etch-and-rinse, fluoride-containing adhesives, Optibond FL (FL and Optibond Solo Plus (SP, respectively. Restored teeth were subjected to thermal cycling to age the interface. Both SP and FL adhesive-restored teeth were bleached (n = 10 with 10% CP (CP and 10% CP + fluoride (CPF or were left unbleached (control. Bleaching was performed for 14 days simultaneously with pH cycling, which comprised of 14 h of remineralization, 2 h of demineralization and 8 h of bleaching. The control groups (FL and SP were stored in remineralizing solution during their bleaching periods and were also subjected to carious lesion formation. Parallelepiped-shaped samples were obtained from the bonded interface for microtensile bond strength (∝TBS testing. The enamel ∝TBS of the FL and SP groups (control, not bleached were higher (p FL + CPF = FL + CP and SP > SP + CPF = SP + CP. The groups subjected to treatment with the fluoride-containing bleaching agents exhibited similar ∝TBS compared to regular bleaching agents. Bleaching agents, regardless of whether they contained fluoride, decreased enamel bond strength.

  12. Influence of fluoride-containing adhesives and bleaching agents on enamel bond strength.

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    Cavalli, Vanessa; Liporoni, Priscila Cristiane Suzy; Rego, Marcos Augusto do; Berger, Sandrine Bittencourt; Giannini, Marcelo

    2012-01-01

    This study evaluated the influence of fluoride-containing carbamide peroxide (CP) bleaching agents and adhesive systems on bonded enamel interfaces that are part of the dynamic pH cycling and thermal cycling models. The buccal surfaces of 60 bovine incisors were restored with a composite resin and bonded with three- and two-step, etch-and-rinse, fluoride-containing adhesives, Optibond FL (FL) and Optibond Solo Plus (SP), respectively. Restored teeth were subjected to thermal cycling to age the interface. Both SP and FL adhesive-restored teeth were bleached (n = 10) with 10% CP (CP) and 10% CP + fluoride (CPF) or were left unbleached (control). Bleaching was performed for 14 days simultaneously with pH cycling, which comprised of 14 h of remineralization, 2 h of demineralization and 8 h of bleaching. The control groups (FL and SP) were stored in remineralizing solution during their bleaching periods and were also subjected to carious lesion formation. Parallelepiped-shaped samples were obtained from the bonded interface for microtensile bond strength (μTBS) testing. The enamel μTBS of the FL and SP groups (control, not bleached) were higher (p FL > FL + CPF = FL + CP and SP > SP + CPF = SP + CP). The groups subjected to treatment with the fluoride-containing bleaching agents exhibited similar μTBS compared to regular bleaching agents. Bleaching agents, regardless of whether they contained fluoride, decreased enamel bond strength.

  13. The combination of sodium perborate and water as intracoronal teeth bleaching agent

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    Ananta Tantri Budi

    2008-12-01

    Full Text Available Background: The color change on post-endodontic treated teeth can be overcome by intracoronal tooth bleaching using walking bleach. Some agents used in walking bleach are combination of sodium peroxide and hydrogen peroxide, and combination of sodium perborate and water. Purpose: The objective of this review is to provide information and consideration of using safe and effective bleaching agents in the field of dentistry. Reviews: On one side, the use of sodium perborate and water combination does not cause the reduction of dentin hardness, enamel decay, and root resorbtion. On the other side, the use of sodium perborate and 30% hydrogen peroxide combination indicates that it takes longer time in yielding the proper color of teeth. Conclusion: The use of sodium perborate and water combination as bleaching agents is effective and safe.

  14. Evaluation and comparison of the microhardness of enamel after bleaching with fluoride free and fluoride containing carbamide peroxide bleaching agents and post bleaching anticay application: An in vitro study

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    Liza George

    2015-01-01

    Full Text Available Aims and Objectives: The purpose of the study was to evaluate and compare the microhardness of enamel after the application of anticay on bleached enamel with fluoride containing and fluoride free bleaching agent. Materials and Methods: Twenty freshly extracted teeth decoronated and divided mesiodistally into two halves were randomly divided into five groups with 10 samples in each group. The enamel surface was treated as follows: Group 1 - no treatment, Group 2 - fluoride free bleaching agent, Group 3 - fluoride containing bleaching agent, and Group 4 - fluoride free bleaching agent followed by anticay application. The samples were subjected to indentation to test the microhardness using Vicker's hardness analyzer. Conclusion: Enamel microhardness significantly increased in samples where anticay was used after the application of bleaching agent.

  15. Coral bleaching independent of photosynthetic activity.

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    Tolleter, Dimitri; Seneca, François O; DeNofrio, Jan C; Krediet, Cory J; Palumbi, Stephen R; Pringle, John R; Grossman, Arthur R

    2013-09-23

    The global decline of reef-building corals is due in part to the loss of algal symbionts, or "bleaching," during the increasingly frequent periods of high seawater temperatures. During bleaching, endosymbiotic dinoflagellate algae (Symbiodinium spp.) either are lost from the animal tissue or lose their photosynthetic pigments, resulting in host mortality if the Symbiodinium populations fail to recover. The >1,000 studies of the causes of heat-induced bleaching have focused overwhelmingly on the consequences of damage to algal photosynthetic processes, and the prevailing model for bleaching invokes a light-dependent generation of toxic reactive oxygen species (ROS) by heat-damaged chloroplasts as the primary trigger. However, the precise mechanisms of bleaching remain unknown, and there is evidence for involvement of multiple cellular processes. In this study, we asked the simple question of whether bleaching can be triggered by heat in the dark, in the absence of photosynthetically derived ROS. We used both the sea anemone model system Aiptasia and several species of reef-building corals to demonstrate that symbiont loss can occur rapidly during heat stress in complete darkness. Furthermore, we observed damage to the photosynthetic apparatus under these conditions in both Aiptasia endosymbionts and cultured Symbiodinium. These results do not directly contradict the view that light-stimulated ROS production is important in bleaching, but they do show that there must be another pathway leading to bleaching. Elucidation of this pathway should help to clarify bleaching mechanisms under the more usual conditions of heat stress in the light.

  16. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

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    Mohammad E. Rokaya

    2015-01-01

    Full Text Available Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n=27 according to the bleaching materials used. Each main group was divided into three subgroups (n=9 according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide, group 2 (35% carbamide peroxide, group 3 (sodium perborate-30% hydrogen peroxide mixture, and group 4 (sodium perborate-water mixture. Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey’s test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  17. In vitro study of the pulp chamber temperature rise during light-activated bleaching

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    Thaise Graciele Carrasco

    2008-10-01

    Full Text Available This study evaluated in vitro the pulp chamber temperature rise induced by the light-activated dental bleaching technique using different light sources. The root portions of 78 extracted sound human mandibular incisors were sectioned approximately 2 mm below the cementoenamel junction. The root cavities of the crowns were enlarged to facilitate the correct placing of the sensor into the pulp chamber. Half of specimens (n=39 was assigned to receive a 35% hydrogen peroxide gel on the buccal surface and the other halt (n=39 not to receive the bleaching agent. Three groups (n=13 were formed for each condition (bleach or no bleach according to the use of 3 light sources recommended for dental bleaching: a light-emitting diode (LEDlaser system, a LED unit and a conventional halogen light. The light sources were positioned perpendicular to the buccal surface at a distance of 5 mm and activated during 30 s. The differences between the initial and the highest temperature readings for each specimen were obtained, and, from the temperature changes, the means for each specimen and each group were calculated. The values of temperature rise were compared using Kruskal-Wallis test at 1% significance level. Temperature rise varied significantly depending on the light-curing unit, with statistically significant differences (p0.01. When the bleaching agent was applied, there were significant differences among groups (p<0.01: halogen light induced the highest temperature rise (1.41±0.64ºC, and LED-laser system the lowest (0.33±0.12ºC; however, there was no difference between LED-laser system and LED unit (0.44±0.11ºC. LED and LED-laser system did not differ significantly from each other regardless the temperature rise occurred with or without bleaching agent application. It may be concluded that during light-activated tooth bleaching, with or without the bleaching agent, halogen light promoted higher pulp chamber temperature rise than LED unit and LED

  18. Evaluation of an experimental rat model for comparative studies of bleaching agents

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    CINTRA, Luciano Tavares Angelo; BENETTI, Francine; FERREIRA, Luciana Louzada; RAHAL, Vanessa; ERVOLINO, Edilson; JACINTO, Rogério de Castilho; GOMES, João Eduardo; BRISO, André Luiz Fraga

    2016-01-01

    ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

  19. Evaluation of an experimental rat model for comparative studies of bleaching agents

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    Luciano Tavares Angelo Cintra

    2016-02-01

    Full Text Available ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group. Ten animals (control were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05. Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

  20. Evaluation of the effectiveness of an in-office bleaching system and the effect of potassium nitrate as a desensitizing agent.

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    Palé, Maria; Mayoral, Juan R; Llopis, Jaume; Vallès, Marta; Basilio, Joan; Roig, Miguel

    2014-07-01

    The aims of the study were to evaluate by spectrophotometer the in vivo colour changes resulting from the application of an in-office tooth bleaching system containing 28% H2O2 by light-emitting diode (LED) activation and to determine whether the application of 5% potassium nitrate 30 min before bleaching decreased tooth sensitivity. Thirty-two individuals were assigned randomly to two groups (n = 16). Group A received 5% potassium nitrate as a desensitizing agent 30 min before bleaching with 28% hydrogen peroxide activated by LED. Group B received glycerin as a placebo and the same bleaching protocol was applied. The colour of the right central incisor of each patient was measured visually and by spectrophotometer before bleaching, immediately thereafter, 15 days and 3 months later. Differences in L* a* b* values were tested with a repeated measures analysis of variance (ANOVA). Differences in ΔΕ values were tested with ANOVA statistical analysis at a 0.05 level of significance. Significant (p Tooth sensitivity decreased significantly when potassium nitrate was applied. In-office bleaching system gave quantitatively stable results over a 3-month period. Tooth sensitivity was reduced significantly, when a desensitizing agent was applied 30 min before treatment, but the efficacy of bleaching decreased.

  1. Effectiveness of home bleaching agents in discolored teeth and influence on enamel microhardness

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    Carina Sinclér Delfino

    2009-08-01

    Full Text Available OBJECTIVES: This study evaluated the effectiveness of different home bleaching agents on color alteration and their influence on surface and subsurface microhardness of discolored bovine enamel. MATERIAL AND METHODS: Forty-five fragments of bovine incisors were randomly allocated into 3 groups (n=15 according to the bleaching agent: 10% carbamide peroxide gel (CP10, 16% carbamide peroxide gel (CP16 and 6.5%-hydrogen-peroxide-based strip (HP6.5. Before bleaching treatment, initial values of Knoop surface microhardness and color (CIEL*a*b* were obtained and the fragments were artificially stained in hemolyzed rat blood. Then, bleaching treatments were performed over a 21-day period. Color changes (ΔE were assessed at 7, 14 and 21 days, and final surface microhardness reading was done after 21 days. Thereafter, the fragments were bisected to obtain subsurface microhardness. Data were subjected to ANOVA and Tukey's tests (α=5%. RESULTS: Color changes produced by CP16 were similar to those of CP10, and the color changes produced by these materials were significantly superior to those produced by HP6.5. Color changes at 21 days were superior to 7 days and similar to 14 days. The time did not influence color changes for CP16, which showed similarity between the 14- and 21-day results. No statistically significant differences were found among the home bleaching agents for surface and subsurface microhardness. CONCLUSIONS: Microhardness of bovine enamel was not affected by the bleaching agents. The 16% carbamide peroxide gel was the most effective for bleaching the stained substrate.

  2. Study of the hydrogen peroxide bleaching agent effects on bovine enamel using X-ray fluorescence

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    Moreira, Ruda F.; Calazans, Fernanda S.; Miranda, Mauro S.; Santos, Ramon S.; Anjos, Marcelino J.; Assis, Joaquim T. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Hydrogen Peroxide's a bleaching agent capable of oxidizing a wide range of colored organic, causing discoloration and hence bleaching of the substrate, but some authors related the occurrence of side effects related to bleaching of the tooth structure, such as changes in morphology superficial. It was used 6 bovine incisors, each tooth was initially evaluated six times in different areas to obtain the count of elements phosphorus and calcium using X-Ray Fluorescence. The teeth were randomly divided in two groups: both groups were submitted to bleaching in office with hydrogen peroxide 38%, once a week during three weeks. Group 1 was stored in distilled water and group 2 in artificial saliva, between the sessions. The measurements were repeated every seven days before the bleaching treatment. Besides that, changes in mineral levels were always assessed in the same area and using the same procedure. It was observed that the bleaching was not able to demineralize the tooth enamel studied. (author)

  3. Study of DNA damage induced by dental bleaching agents in vitro Estudo de danos no DNA induzidos por agentes clareadores dentais in vitro

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    Daniel Araki Ribeiro

    2006-03-01

    Full Text Available Dental bleaching is a simple and conservative procedure for aesthetic restoration of vital and non-vital discolored teeth. Nevertheless, a number of studies have demonstrated the risk of tissue damage from the contact of these agents with the oral mucosa. In the current study, the genotoxic potential associated with exposure to dental bleaching agents was assessed by the single cell gel (comet assay in vitro. Chinese hamster ovary (CHO cells in vitro were exposed to six commercial dental bleaching agents (Clarigel Gold - Dentsply; Whitespeed - Discus Dental; Nite White - Discus Dental; Magic Bleaching - Vigodent; Whiteness HP - FGM and Lase Peroxide - DMC. The results pointed out that all dental bleaching agents tested contributed to DNA damage as depicted by the mean tail moment, being the strongest effect observed with the highest dose of hydrogen peroxide (Whiteness HP and Lase Peroxide, at a 35% concentration. On the other hand, Magic Bleaching (Vigodent induced the lowest level of DNA breakage. Negative and positive controls displayed absence and presence of DNA-damaging, respectively. Taken together, these results suggest that dental bleaching agents may be a factor that increases the level of DNA damage. A higher concentration of hydrogen peroxide produced higher noxious activities in the genome as detected by single cell gel (comet assay.Clareamento dental é um procedimento simples e conservador para restaurar esteticamente a cor de dentes vitais e não-vitais. Entretanto, alguns estudos têm demonstrado o risco de dano tecidual a partir do contato desses agentes com a mucosa bucal. Neste presente estudo, o potencial genotóxico associado à exposição aos agentes clareadores dentais foi avaliado pelo teste de células individualizadas em gel (teste do cometa in vitro. Células de ovário de hamster chinês (CHO in vitro foram expostas a seis agentes clareadores dentais comercialmente disponíveis (Clarigel Gold - Dentsply; Whitespeed

  4. Sunflower oil bleaching by adsorption onto acid-activated bentonite

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    E. L. Foletto

    2011-03-01

    Full Text Available Two bentonite clays with different mineralogical compositions from Mendoza, Argentine, were activated with H2SO4 solutions of 4 and 8 N at 90ºC for 3.5 hours. This treatment affected clay structural properties, as was shown by thermogravimetry, infrared spectrometry and chemical analysis. Bleaching efficiency for sunflower oil was strongly dependent on the acid concentration used for clay activation. The samples have bleaching capacity comparable to that observed with a commercial adsorbent standard. The mineralogical composition of natural clays influenced the properties of the activated clays.

  5. Effect of tooth bleaching agents on protein content and mechanical properties of dental enamel.

    Science.gov (United States)

    Elfallah, Hunida M; Bertassoni, Luiz E; Charadram, Nattida; Rathsam, Catherine; Swain, Michael V

    2015-07-01

    This study investigated the effect of two bleaching agents, 16% carbamide peroxide (CP) and 35% hydrogen peroxide (HP), on the mechanical properties and protein content of human enamel from freshly extracted teeth. The protein components of control and treated enamel were extracted and examined on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Marked reduction of the protein matrix and random fragmentation of the enamel proteins after bleaching treatments was found. The mechanical properties were analyzed with Vickers indentations to characterize fracture toughness, and nanoindentation to establish enamel hardness, elastic modulus and creep deformation. Results indicate that the hardness and elastic modulus of enamel were significantly reduced after treatment with CP and HP. After bleaching, the creep deformation at maximum load increased and the recovery upon unloading reduced. Crack lengths of CP and HP treated enamel were increased, while fracture toughness decreased. Additionally, the microstructures of fractured and indented samples were examined with field emission gun scanning electron microscopy (FEG-SEM) showing distinct differences in the fracture surface morphology between pre- and post-bleached enamel. In conclusion, tooth bleaching agents can produce detrimental effects on the mechanical properties of enamel, possibly as a consequence of damaging or denaturing of its protein components.

  6. Comparative study of the action of two different types of bleaching agents activated by two different types of irradiation fonts: xenon plasma arc lamp and 960 nm diode laser; Avaliacao da cor e estudo comparativo da acao de dois tipos diferentes de agentes clareadores ativados pelo laser de diodo e lampada xenonio plasmatica, na superficie do esmalte

    Energy Technology Data Exchange (ETDEWEB)

    Walverde, Debora Ayala

    2001-07-01

    This in vitro study compares two different types of tooth bleaching agents stimulated with two different irradiation fonts. These fonts accelerate the action of the bleaching agents upon the enamel surface by heating up the materials. We used the xenon plasma arc lamp and a 960 nm fiber-coupled diode laser to irradiate the two materials containing 35% of hydrogen peroxide (Opus White and Opalescence extra). The color of the teeth was measured with a spectrophotometer using the CIELAB color system that gives the numeric values of L{sup *}a{sup *}b{sup *}. (author)

  7. Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

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    Ana Flávia Soares

    2016-02-01

    Full Text Available ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10, each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL or diode laser/violet LED (VHL (experimental: Control (C; 35% Total Blanc Office (TBO35HL; 35% Lase Peroxide Sensy (LPS35HL; 25% Lase Peroxide Sensy II (LPS25HL; 15% Lase Peroxide Lite (LPL15HL; and 10% hydrogen peroxide (experimental (EXP10VHL. pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm. ANOVA and Tukey´s tests were applied (α=0.05. Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups.

  8. Comparison of the bleaching efficacy of three different agents used for intracoronal bleaching of discolored primary teeth: An in vitro study

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    R Ganesh

    2013-01-01

    Full Text Available Everyone wants whiter teeth to make them feel younger and to provide beautiful smiles with the accompanying increase in self-esteem. Bleaching is an established, simple, cost-effective and conservative method for improving the color of the discolored teeth. Aim: The aim of this in vitro study was to compare the bleaching efficacy of 10% carbamide peroxide, 10% hydrogen peroxide and 2g sodium perborate as bleaching agents on the artificially discolored human primary maxillary central incisors. Materials and Methods: Forty extracted human primary central incisors with intact crowns were selected for the study. Pulpectomy was performed and each tooth was artificially stained with 2 ml of fresh human blood and centrifuged. --The teeth were randomly divided into four experimental groups of 10 teeth each and the baseline color evaluation was performed. 0.04 ml of the bleaching agent is syringed into the access cavity of the tooth and, in the control group, 0.04 ml of distilled water was syringed into the access cavity and it was sealed with IRM and placed at 37°C in an incubator throughout the experiment. The color of the bleached teeth was determined at 0, 7 and 14 days. The data obtained were analyzed using ANOVA and Turkey′s test. Results: There was statistical significance (P = 0.00 among the carbamide peroxide, sodium perborate, hydrogen peroxide and control groups after 7 and 14 days and a significance of P = 0.013 among the carbamide peroxide, sodium perborate and hydrogen peroxide after two bleaching sessions (day 14 was seen. Conclusions: The bleaching efficacy of 10% hydrogen peroxide gel was more effective than 10% carbamide peroxide and sodium perborate in bleaching the artificially discolored primary teeth.

  9. The bleaching agents on the impact of the composite resin%漂白剂对复合树脂的影响

    Institute of Scientific and Technical Information of China (English)

    苏伟珠; 王浙君; 撒悦

    2012-01-01

    With the popularity of cosmetic restoration, it is common for the dentist to treat the bleached teeth with composite resin restoration, or in some cases, bleach the teeth which have existed composite resin restorations. Due to the strong oxidizing ability and reaction activity, bleaching agents could typically affect the properties of composite resin to some extence, such as microhardness, surface roughness, etc. Therefore, evzaluation about the effects of bleaching agents on dental composite resin appears valuable. This review summarized the bleaching agents on the impact of the composite resin in aspects: Surface property, bonding strength with enamel and dentin, mi-croleakage and color.%临床上常需要对存在复合树脂修复体的牙进行漂白,或者对漂白后的牙进行复合树脂修复.由于漂白剂具有较强的氧化性及反应活性,在一定程度上影响了复合树脂的性能如微硬度、表面粗糙度等;因此,研究漂白剂对复合树脂的影响有重要的临床意义.本文就漂白剂对复合树脂表面性能、与釉质和牙本质粘接强度、微渗漏、颜色等的影响作一综述.

  10. Effect of intracoronal bleaching agents on ultrastructure and mineral content of dentin

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    Fatemeh Maleknejad

    2012-01-01

    Full Text Available Aim: The purpose of this in vitro study was to evaluate the ultrastructural changes of dentin induced after exposure to different intracoronal tooth bleaching agents. Materials and Methods: Dental discs of 1 mm thickness were prepared from coronal dentin of sixty-four human maxillary premolars. Experimental specimens were divided into four subgroups: 45% carbamide peroxide, 35% hydrogen peroxide, sodium perborate + 30% hydrogen peroxide, sodium perborate + water. The specimens were then evaluated under scanning electron microscope to determine diameter of dentinal tubules and chemical analysis. Results: There was significant difference between dentinal tubule diameter of all test and control groups with the exception of sodium perborate + water. Chemical analysis revealed that there was no significant difference between experimental subgroups regarding calcium and sulfur wt%. Conclusions: All bleaching agents increased dentinal tubule diameter and promote alterations in mineral content of dentin with the exception of Sodium perborate mixed with water.

  11. Comparative evaluation of two different remineralizing agents on the microhardness of bleached enamel surface: Results of an in vitro study

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    Gunpriya Kaur

    2015-01-01

    Conclusion: Both GC Tooth Mousse (Recaldent and Toothmin Tooth cream (Abbott Healthcare Pvt.Ltd increase the microhardness of bleached enamel. Toothmin tooth cream is a better agent for increasing microhardness, although difference is not significant.

  12. Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology

    OpenAIRE

    2004-01-01

    The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment). Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11): control, Whiteness Perfect - 10% carbamide peroxide (10% CP), Colgate Platinum - 10% CP, Day White 2Z - 7.5% hydrogen peroxide (7.5% HP), Whiteness Super - 37% CP, Opalescence Quick - 35% CP and Whiteness HP - ...

  13. The walking bleach procedure: an in vitro study to measure microleakage of five temporary sealing agents.

    Science.gov (United States)

    Hosoya, N; Cox, C F; Arai, T; Nakamura, J

    2000-12-01

    The purpose of this study was to compare the in vitro sealing capacity of five materials, each used as a temporary sealing agent for the walking bleach technique. All teeth received traditional biomechanical root canal instrumentation, after which the walking bleach agent was placed in the pulp chamber space. The occlusal access was sealed with one of five temporary materials: two hydraulic filling materials, a photoactivated resin composite, a zinc oxide-eugenol cement, and a zinc oxide phosphate cement with/without the placement of a piece of rubber sheet that was placed as a barrier to isolate filling material from the bleaching agent. All teeth were stored in a 1% solution of Alcian blue with thermal cycling stress. After 1 wk, they were sectioned longitudinally, and ranked by graded scores of 0 to 3, according to the degree of the dye penetration. Significantly less dye microleakage was observed in the two hydraulic materials than in the photoactivated resin. Both zinc oxide-eugenol and zinc phosphate cements showed a considerable amount of microleakage. There were no significant differences between the groups with and without a rubber sheet. Our data demonstrate that hydraulic filling materials provide the most favorable cavosurface seal when they are firmly packed into the cavity space to prevent microleakage.

  14. LED and low level laser therapy association in tooth bleaching using a novel low concentration H2O2/N-doped TiO2 bleaching agent

    Science.gov (United States)

    Bezerra Dias, Hércules; Teixeira Carrera, Emanuelle; Freitas Bortolatto, Janaína; Ferrarezi de Andrade, Marcelo; Nara de Souza Rastelli, Alessandra

    2016-01-01

    Since low concentration bleaching agents containing N-doped TiO2 nanoparticles have been introduced as an alternative to conventional agents, it is important to verify their efficacy and the hypersensitivity effect in clinical practice. Six volunteer patients were evaluated for color change and hypersensitivity after bleaching using 35% H2O2 (one session of two 12 min applications) and 6% H2O2/N-doped TiO2 (one session of three 12 min applications) and after low level laser therapy application (LLLT) (780 nm, 40 mW, 10 J.cm-2, 10 s). Based on this case study, the nanobleaching agent provided better or similar aesthetic results than the conventional agent under high concentration, and its association with LLLT satisfactorily decreased the hypersensitivity. The 6% H2O2/N-doped TiO2 agent could be used instead of conventional in-office bleaching agents under high concentrations to fulfill the rising patient demand for aesthetics.

  15. Shear Bond Strength of Two Types of Glass Ionomer to Bleached Dentin: Effect of Delayed Bonding and Antioxidant Agent

    Science.gov (United States)

    Omrani, Ladan Ranjbar; Sabouri, Parastoo; Abbasi, Mehdi; Ahmadi, Elham; Ghavam, Maryam

    2016-01-01

    Background: Studies have shown a reduction in bond strength of composites and glass ionomer to bleached enamel and dentin. Several methods have been proposed to reverse compromised bond strength. Objective: The aim of this study was to evaluate the effect of delayed bonding and application of antioxidant agent on the bond strength of reinforced self-cured (Fuji IX) and light-cured glass ionomers (Fuji II LC) to bleached dentin. Material: Eighty extracted third molars were randomly divided into 8 groups. Buccal dentin surfaces received different treatments: Two control groups: no treatment + bonding Fuji IX or Fuji II LC. Two immediate bonding groups: bleaching + bonding Fuji IX or Fuji II LC. Two delayed bonding groups: bleaching + 7 days delay + bonding Fuji IX or Fuji II LC. Two sodium ascorbate application groups: Bleaching + application of 10% sodium ascorbate + bonding Fuji IX or Fuji II LC. All samples were tested for shear bond strength. Two-way analysis of variance (ANOVA) was used to compare the mean and standard deviations among groups, followed by the Tukey’s test for significant interaction. Results: No statistically significant difference was detected in shear bond strength of Fuji IX to bleached or normal dentin. Although a significant reduction was found shear bond strength values of Fuji II LC to bleached dentin, no significant difference was observed between no bleaching group and those treated with 10% sodium ascorbate or 7 days of delay in bonding for both types of glass ionomer. Conclusion: Bleaching had no significant effect on shear bond strength of Fuji IX to dentin; this type of GI can be used immediately after bleaching. PMID:28217187

  16. Influence of bleaching agents on the microhardness of nanoparticle resin composite

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    Vanderlei Salvador Bagnato

    2009-01-01

    Full Text Available Objective: To assess the effect of bleaching agents on the microhardness of nanoparticle resin composite. Methods: Twenty-eight cylindrical test specimens (8x1mm of FiltekTM Supreme XT resin (3M/ESPE were prepared and divided into 5 groups. The initial Vickers microhardness was measured (load of 50 grams force for 30 seconds on the top surface of the test specimens. The groupswere treated and divided as follows: G1 – artificial saliva (21 days - control; G2 - 7% hydrogen peroxide gel applied for 4h/day, for 14 days; G3 - 10% carbamide peroxide for 4h/day, for 14 days: G4 – 35% hydrogen peroxide gel applied in three sessions of 30 minutes each, with an interval of one week (21 days between the sessions; G5 - 35% carbamide peroxide, three sessions of 30 minutes each, with an interval of one week (21 days between the sessions. The top surfaces of the test specimens received treatment and were submitted to the Vickers microhardness test. Results: The results obtained were submitted to the Analysis of Variance at a fixed criterion, at a level of significance of p=0.05. No significant differences were observed among the treatments tested (p=0.42 when compared with G1. Significant differences (Tukey test were found when the initial microhardness values were compared with the values after experimental treatments (p<0.01. Conclusion: The application of bleaching agents did not alter the microhardness of resin composites. Therefore, there is no need to change restorations after bleaching.

  17. Assessment of enamel roughness of bovine teeth bleached with and without laser activation

    OpenAIRE

    Rafael Canzi Almada de Paula XAVIER; Rodrigo Mario Pontoni MIRANDA; Gonzaga, Carla Castiglia; Maria da Graça Kfouri LOPES

    2009-01-01

    Introduction: Currently, due to increased demand of patients anddentists for aesthetic treatments, bleaching procedures have becomeroutine in dental treatment. The development of new techniques andmaterials, such as laser-activated bleaching, has gained popularity.However, due to the small number of publications in this area, theiraggressiveness to the enamel is still not known. Objective: To determine the roughness of the enamel surface of bovine teeth bleached with and without laser activat...

  18. Effects of three different bleaching agents on microhardness and roughness of composite sample surfaces finished with different polishing techniques

    Science.gov (United States)

    Yikilgan, İhsan; Akgul, Sinem; Ozcan, Suat; Bala, Oya

    2017-01-01

    Background The aim of this study was to evaluate effects of different polishing methods and whitening agents on surface hardness and roughness of nano-hybrid composite resin. Material and Methods In total, one hundred twenty disc-shaped specimens were prepared to nano-hybrid composite (Charisma Diamond). 60 samples were used for microhardness measurements and the others were used for the evaluation of surface roughness. Samples were divided randomly into two subgroups (n = 30 each). In first group a low-viscosity liquid polishing agent (Biscover LV) was applied. In the second group, nothing was applied. All the samples were stored in distilled water at 37°C for 24 h. After initial measurements were completed, samples were divided randomly into three subgroups for bleaching application. 10% carbamide peroxide (Opalescence PF), 45% carbamide peroxide (Opalescence PF Quick), 38% hydrogen peroxide (Opalescence Boost) was applied. Then microhardness and surface roughness measurements of samples were repeated and data were recorded as final values for each sample. Results When the polishing techniques were compared, no signicant difference was observed in surface hardness and roughness. When the bleaching agents were compared, the 10% carbamide peroxide and 38% hydrogen peroxide containing bleaching agent groups showed statistically significant differences between pre- and post-procedure hardness values (p<0.05). Conclusions Office-type bleaching agent containing CP was observed to be more secure for composite resins than other bleaching agents. No negative effect of glaze materials on the protection of surface roughness and hardness of composite resin was observed. Key words:Composite resin, bleaching, surface hardness, surface roughness. PMID:28298992

  19. Effect of a Home Bleaching Agent on the Fracture Toughness of Resin Composites: using short rod design

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    Bagheri R.

    2013-10-01

    Full Text Available Statement of Problem: Resin composites are brittle materials and their major shortcomings are manifested in their sensitivity to flaws and defects. Although various mechanical properties of resin composites have been described, few studies are available on assessing the effect of bleaching agents on resin composites using the short rod design. Materials and Method: Specimens were prepared from three resin composites; Rok (SDI, Esthet (Dentsply, and Estelite (Tokuyama. For each material, a total of 24 disc-shaped specimens were prepared using a custom-made mould. Specimens were randomly divided into 3 groups of 8 and conditioned in 37°C distilled water for either 24 hours, or 21 days. 21 day specimens were tested both with and without applying bleaching agent; Polanight (SDI. Study group specimens were bleached for 21 days, 2 hours a day. The specimens were loaded using a universal testing machine with a crosshead speed of 0.5 mm per minute. The maximum load at specimen failure was recorded and the KIc (MPa. M 0.5 was calculated. Results: Statistical analysis using two-way ANOVA showed a significant relationship between material and time (p< 0.05. Tukey’s test showed that after 24 h of immersion in distilled water, Rok revealed the highest KIc followed by Esthet and Estelite. The bleaching agent significantly improved the fracture toughness values of Esthet while it decreased that of Estelite. Conclusion: The fracture toughness of the resin composites was affected by the bleaching agent and distilled water. In comparison with Rok and Estelite, fracture toughness of Esthet was increased due to aging and application of bleaching agent.

  20. Efektivitas Desensitizing Agent dengan dan tanpa Fluor pada Metode in Office Bleaching terhadap Kandungan Mineral Gigi (Kajian In Vitro

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    Yulita Kristanti

    2015-12-01

    Full Text Available In office bleaching menggunakan hidrogen peroksida 40% sering memberikan efek samping berupa linu baik selama maupun setelah perawatan tersebut dilakukan. Penelitian ini dilakukan dengan tujuan untuk mengetahui pengaruh waktu aplikasi dan kandungan fluor desensitizing agent pada metode in office bleaching terhadap kandungan mineral gigi. Delapan gigi masing-masing dipotong menjadi 4 bagian, 6 potong digunakan untuk pemeriksaan XRD awal. Gigi dikeringkan dalam oven suhu 50° selama 30 menit diserbuk, diambil 1 mg untuk diperiksa kandungan mineralnya dengan goniometer. Dua puluh empat potong yang lain dibagi dalam 4 kelompok perlakuan. Kelompok I: gigi diaplikasi bahan bleaching 0,5-1 mm hidrogen peroksida 40% selama 1 jam, dicuci, dikeringkan, diikuti aplikasi 0,1 ml desensitizing agent tanpa fluor (CPP-ACP selama 30 menit, dicuci, dikeringkan. Kelompok II : gigi diaplikasi CPP-ACP 30 menit, dicuci, dikeringkan, dibleaching menggunakan hidrogen peroksida 40% selama 1 jam. Selanjutnya gigi diaplikasi CPP-ACP 30 menit lagi, dicuci, dikeringkan. Kelompok III gigi dibleaching menggunakan hidrogen peroksida 40% selama 1 jam, dicuci, dikeringkan, diikuti aplikasi desensitizing agent yang mengandung fluor (CPP-ACFP selama 30 menit, dicuci, dikeringkan. Kelompok IV: gigi diaplikasi CPP-ACFP 30 menit, dicuci, dikeringkan, dibleaching menggunakan hidrogen peroksida 40% selama 1 jam. Selanjutnya gigi diaplikasi CPP-ACFP selama 30 menit, dicuci dikeringkan. Sesudah perlakuan, semua gigi dilakukan pemeriksaan kandungan mineral gigi dengan prosedur yang sama. Uji Mann Whitney menunjukkan penurunan mineral paling sedikit terjadi pada kelompok IV (4500. Desensitizing agent mengandung F sebelum dan sesudah perlakuan in office bleaching menunjukkan penurunan mineral paling kecil.   The Effectiveness of Desensitizing Agent with and without Fluorine in Office Bleaching Method to Tooth Mineral content. Tooth sensitivity arises during or after an in

  1. Shear bond strength to enamel after power bleaching activated by different sources.

    Science.gov (United States)

    Can-Karabulut, Deniz C; Karabulut, Baris

    2010-01-01

    The purpose of the present study was to evaluate enamel bond strength of a composite resin material after hydrogen peroxide bleaching, activated by a diode laser (LaserSmile), an ozone device (HealOzone), a light-emitting diode (BT Cool whitening system), and a quartz-Plus. Fifty extracted caries-free permanent incisors were used in this study. Thirty-eight percent hydrogen peroxidegel was applied to sound, flattened labial enamel surfaces and activated by different sources. Enamel surfaces that had received no treatment were used as control samples. Bonding agent was applied according to the manufacturer's instructions and the adhesion test was performed according to ISO/TS 11405. Statistical analysis showed significant influence of the different activation technique of hydrogen peroxide on shear bond strength to enamel (ANOVA, LSD, P composite resin restoration to enamel. Within the limitations of this in vitro study, further studies examining the structural changes of activated hydrogen peroxide-treated enamel are needed. Due to the different activation methods; duration of light irradiation effects, longer time periods may be needed before application of adhesive restorations to enamel, compared with non-activated bleaching.

  2. Recognizing a limitation of the TBLC-activated peroxide system on low-temperature cotton bleaching.

    Science.gov (United States)

    Chen, Wenhua; Wang, Lun; Wang, Dong; Zhang, Jingjing; Sun, Chang; Xu, Changhai

    2016-04-20

    In this study, cotton was bleached at low temperatures with an activated peroxide system which was established by incorporating a bleach activator, namely, N-[4-(triethylammoniomethyl)benzoyl]caprolactam chloride (TBCC) into an aqueous solution of hydrogen peroxide (H2O2). Experimental results showed that the bleaching performance was unexpectedly diminished as the TBCC concentration was increased over the range of 25-100g/L. Kinetic adsorption experiment indicated that this was most likely ascribed to the adsorptive interactions of TBCC and the in situ-generated compounds with cotton fibers. Such a limitation was especially fatal to cold pad-batch bleaching process of cotton in which a high TBCC concentration was often required. The results of this study may stimulate further research to avoid or overcome the limitation of the TBCC-activated peroxide system on low-temperature cotton bleaching.

  3. Effect of light activation on tooth sensitivity after in-office bleaching.

    Science.gov (United States)

    Kossatz, S; Dalanhol, A P; Cunha, T; Loguercio, A; Reis, A

    2011-01-01

    This clinical study evaluated the effects of light-emitting diode (LED)/laser activation on bleaching effectiveness (BE) and tooth sensitivity (TS) during in-office bleaching. Thirty caries-free patients were divided into two groups: light-activated (LA) and non-activated (NA) groups. A 35% hydrogen peroxide gel (Whiteness HP Maxx, FGM Dental Products, Joinville SC, Brazil) was used in three 15-minute applications for both groups. For the LA group, LED/laser energy (Whitening Lase Light Plus, DMC Odontológica, São Carlos SP, Brazil) was used, in accordance with the manufacturer's directions. Two sessions of bleaching were performed at one-week intervals. Color was registered at baseline and after the first and second bleaching sessions using a Vita shade guide. Patients recorded TS on a 0 to 4 scale during bleaching and within the next 24 and 48 hours of each session. BE at recall each week and intensity of TS were evaluated by repeated measures analysis of variance (ANOVA) and Tukey tests (α=0.05). Tooth sensitivity was compared using the Friedman repeated measures analysis of variance by rank and the Wilcoxon sign-ranked test. Faster bleaching was observed for the LA group than for the NA group after the first session (4.8 and 3.8 shade guide units [SGUs]; p=0.0001). However, both techniques were capable of bleaching the same number of SGUs after the second bleaching session (p=0.52). Most of the LA group (53.3%) had sensitivity even 24 hours after each bleaching session, but only 26.6% from the NA group reported TS. The intensity of TS was similar for both groups immediately after bleaching but significantly higher for the LA group 24 hours after each bleaching session (p=0.001). After two bleaching sessions, the use of LED/laser light activation did not improve bleaching speed. Persistent tooth sensitivity and higher tooth sensitivity after 24 hours of bleaching were observed when light activation was used.

  4. Performance of an Argentinian acid-activated bentonite in the bleaching of soybean oil

    Directory of Open Access Journals (Sweden)

    Foletto E.L.

    2003-01-01

    Full Text Available In this work, a bentonite clay from Mendoza, Argentina was activated with H2SO4 (4 and 8 N at 90ºC for 2 and 3.5 hours. Under these conditions several cations were removed from the octahedral sheet (Mg, Al, and Fe and the DTA-TGA curves of the solids obtained after treatment were modified. Treatment time and acid concentration increased the degree of destruction of the bentonite structure. Activated samples were tested in order to verify their capacity to bleach soybean oil and were compared to a standard commercial bleaching clay. Treated samples are more efficient in bleaching than the standard.

  5. Mercury release of amalgams with various silver contents after exposure to bleaching agent

    Science.gov (United States)

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P dental amalgam. PMID:27429729

  6. Efficacy of desensitizing agents on postoperative sensitivity following an in-office vital tooth bleaching: A randomized controlled clinical trial

    Science.gov (United States)

    Nanjundasetty, Jyothi Kashi; Ashrafulla, Mohammed

    2016-01-01

    Aim: To assess and compare the incidence and intensity of experienced after an in-office vital tooth bleaching in case of dental fluorosis using two different types of desensitizing agents, at different time periods. Materials and Methods: Sixty-nine subjects with mild-to-moderate fluorosis were randomly divided into three groups of 23 each. Group I — control group (placebo), group II—potassium nitrate 5% and sodium monofluorophosphate 0.7% (Sensodent KF), and group III—Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) (Tooth Mousse). In-office vital tooth bleaching was done using 35% hydrogen peroxide liquid (Pola office) in two sessions. Desensitizing agent was applied for 10 min after each session. Postoperative sensitivity was recorded after 24 h and 7 days. The statistical analysis was done using chi-square test, analysis of variance (ANOVA), and post hoc Tukey's test. Results: The experimental groups showed significantly less incidence and intensity of sensitivity compared to control group, whereas there was no difference between them. Conclusion: The desensitizing agents used in the study show effective reduction after an in-office vital tooth bleaching. PMID:27217631

  7. Efficacy of desensitizing agents on postoperative sensitivity following an in-office vital tooth bleaching: A randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Jyothi Kashi Nanjundasetty

    2016-01-01

    Full Text Available Aim: To assess and compare the incidence and intensity of experienced after an in-office vital tooth bleaching in case of dental fluorosis using two different types of desensitizing agents, at different time periods. Materials and Methods: Sixty-nine subjects with mild-to-moderate fluorosis were randomly divided into three groups of 23 each. Group I - control group (placebo, group II-potassium nitrate 5% and sodium monofluorophosphate 0.7% (Sensodent KF, and group III-Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP (Tooth Mousse. In-office vital tooth bleaching was done using 35% hydrogen peroxide liquid (Pola office in two sessions. Desensitizing agent was applied for 10 min after each session. Postoperative sensitivity was recorded after 24 h and 7 days. The statistical analysis was done using chi-square test, analysis of variance (ANOVA, and post hoc Tukey′s test. Results: The experimental groups showed significantly less incidence and intensity of sensitivity compared to control group, whereas there was no difference between them. Conclusion: The desensitizing agents used in the study show effective reduction after an in-office vital tooth bleaching.

  8. Effect of two bleaching agents on enamel morphology: a SEM study

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    Ghavam M.

    2005-05-01

    Full Text Available Statement of Problem: Bleaching materials are able to change the surface morphology as well as mineral and organic content of tooth structure. Considering that bleaching is done for aesthetic purpose, awareness of the possible effect of these materials on hard tissue is important, because it may affect the restorative treatments. Purpose: The aim of this study was comparing the effect of two bleaching materials, Kimia and Ultradent both containing 35% H2O2, on tooth enamel by SEM. Materials and Methods: Five intact central incisors were cut into three sections vertically and each part was randomly divided into three groups. Group 1 (control, without any bleaching. Group 2, bleached with Kimia 35% H2O2. Group 3, bleached with Ultradent 35% H2O2. Each tooth served as its own control. Then the samples were observed by SEM with 250 and 500 magnifications. Results: In the control group some scratches and small white grains were observed which seems to be the result of mastication trauma and pumice powder. In the other groups, morphologic changes like increased surface roughness, deepening of cracks, rod exposure and presence of new cracks were observed. The two experimental materials did not differ in these regards. Conclusion: It seems that both studied materials have limited destructive effects on tooth enamel which seems to be of no clinical importance.

  9. The Role of Home Bleaching Agent on the Fracture Toughness of Resin Composites Using Four-Point Bending Test

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    Ghazvini Ferooz M

    2014-09-01

    Full Text Available Statement of Problem: Resin composites are a common type of tooth coloured restorative materials. These materials are brittle and their major shortcomings are sensitivity to flaws and defects, low tensile strength, and susceptibility to catastrophic failure.The role of home bleaching agents on the fracture toughness of resin composites using four-point bending test is scanty. Objectives: To compare the fracture toughness (KIc of resin composites on a fourpoint bending test and to assess the effect of distilled water and a home bleaching agent on the resistance of the materials to fracture. Materials and Methods: seventy-two bar-shaped specimens were prepared from three materials: Rok (SDI, Estelite (Tokuyama, and Vit-l-escence (Ultradent and divided into three groups. Two groups were assigned as “control” and conditioned in distilled water at 37oC for 24 hours or 21 days, respectively. The specimens in the third group (treatment were stored in distilled water for 21 days and bleached using Polanight (SDI for 2 hours daily. For each material, a total of 24 disc-shaped specimens were prepared and after each time interval loaded in a four-point bending test using a universal testing machine with a crosshead speed of 0.5 mm/m. The maximum load to specimen failure was recorded and the KIc was calculated. Results: Statistical analysis using two-way ANOVA showed a significant relationship between materials and treatment (P<0.05. Tukey’s test showed that after 24 hours of immersion in distilled water, KIc was not significantly different between materials; Rok revealed the highest value followed by Estelite and Vit-l-escence. The bleaching agent significantly decreased the KIc values of Estelite and Rok while it did not affect that of Vita-l-escence. Immersion in distilled water for all resin composites caused a significant decrease in KIc. Conclusion: The fracture toughness of the resin composites was affected by the bleaching agent and 21day

  10. Micromorphology and microhardness of enamel after treatment with home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Robson Tetsuo Sasaki

    2009-12-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the effect of home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide on enamel microhardness and surface micromorphology. MATERIAL AND METHODS: Enamel slabs (n=10 received the bleaching agents for 1 h/day and remained in artificial saliva solution for 23 h/day, during a total period of 21 days. Control group was composed of enamel slabs that were not subjected to treatment with the agents and were maintained in artificial saliva solution. Microhardness tests were performed before treatment application, 21 days of treatment and 14 days after the end of treatment. Scanning electron microscopy analyses were performed after 14 days after the end of bleaching treatment by 3 calibrated observers who attributed scores. RESULTS: The Tukey's test (α=0.05 showed no significant differences in microhardness values among bleaching agents, at 21 days of treatment and a significant increase in microhardness for different agents after 14 days from the end of treatment. Fisher's exact test showed differences in micromorphology of enamel between control and experimental groups (p=0.0342. CONCLUSIONS: Bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide may change surface micromorphology of enamel, although no changes in microhardness were observed.

  11. Efficacy of Home-use Bleaching Agents Delivered in Customized or Prefilled Disposable Trays: A Randomized Clinical Trial.

    Science.gov (United States)

    Carlos, N R; Bridi, E C; Amaral, Flb; França, Fmg; Turssi, C P; Basting, R T

    The purpose of this study was to evaluate bleaching methods containing hydrogen peroxide (HP) or carbamide peroxide (CP), dispensed in customized or prefilled trays, in terms of color change, tooth sensitivity, gingival irritation, acceptance, and comfort. Seventy-five volunteers were randomly selected and distributed according to the whitening agent (n=25): 10% HP dispensed in prefilled trays (Opalescence Go 10%) and 9.5% HP (Pola Day) and 10% CP both delivered in customized trays (Opalescence PF 10%). HP was applied for 30 min/d for 14 days (d), and CP for 8 h/d for 14 days. Evaluations were performed at baseline and at 7 days and 14 days of treatment. Color change was measured with Commission internationale de l'éclairage color coordinates (L*, a*, b*), Vita Classical, and 3D Master scales. A visual analog scale was used to assess tooth sensitivity, acceptance of the method and degree of comfort of the tray. Gingival irritation was evaluated as present or absent and localized or generalized. Regarding gingival irritation, tray acceptance, and tooth sensitivity, no differences were observed among the groups at any time (p>0.05). As for degree of comfort, 10% HP showed lower scores (comfortable) than 10% CP, with significant differences (p0.05). The Δb average was higher at 14 days (p0.05). Localized gingival irritation was observed in both tray methods. Mild tooth sensitivity was observed with time, regardless of the bleaching agent concentration or the application time. Color change was similar for all the groups at 7 days and 14 days, but there was a greater reduction in the yellow hue at 14 days. All the bleaching methods were highly accepted and effective in promoting whitening. Although prefilled trays are generally comfortable, they proved less comfortable than customized trays.

  12. The effect of home bleaching agents on the surface roughness of five different composite resins: A SEM evaluation.

    Science.gov (United States)

    Cengiz, Esra; Kurtulmus-Yilmaz, Sevcan; Ulusoy, Nuran; Deniz, Sule Tugba; Yuksel-Devrim, Ece

    2016-05-01

    The aim of this study was to investigate the effect of hydrogen peroxide (HP) and carbamide peroxide (CP) on the surface roughness of five different composite resins using profilometer and scanning electron microscope (SEM). Thirty-six specimens (1 mm thick, 10 mm in diameter) of five composite resins were fabricated. Each composite group was equally divided into three subgroups as control, CP and HP. In control group, specimens were stored in daily refreshed distilled water during the 14-day testing period. In other groups, 10% HP (Opalescence Treswhite) and 10% CP (Opalescence PF) were applied and surface roughness values (Ra) of each specimen were measured with a profilometer at the end of 14 days. Additionally, SEM analysis was performed to evaluate the surface deformations of composite resins. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Ra values of composite groups exposed to bleaching agents were statistically higher than control group (p SEM micrographs showed higher surface alterations at HP group compared to CP. Among the composite resins tested, Ceram-X Mono revealed the lowest Ra values after CP and HP applications as seen at SEM images. Home bleaching agents increased the surface roughness of all composites. Except CP applied Ceram-X mono specimens, Ra values of all composite resins evaluated in this study exceeded the critical limit of 0.2 μm. Ceram-X mono was the least affected composite material after bleaching application. SCANNING 38:277-283, 2016. © 2016 Wiley Periodicals, Inc.

  13. Amphoteric surface active agents

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    Eissa, A.M. F.

    1995-10-01

    Full Text Available 2-[trimethyl ammonium, triethyl ammonium, pyridinium and 2-amino pyridinium] alkanoates, four series of surface active agents containing carbon chain C12, C14, C16 and C18carbon atoms, were prepared. Their structures were characterized by microanalysis, infrared (IR and nuclear magnetic resonance (NMR. Surface and interfacial tension, Krafft point, wetting time, emulsification power, foaming height and critical micelle concentration (cmc were determined and a comparative study was made between their chemical structure and surface active properties. Antimicrobial activity of these surfactants was also determined.

    Se prepararon cuatro series de agentes tensioactivos del tipo 2-[trimetil amonio, trietil amonio, piridinio y 2-amino piridinio] alcanoatos, que contienen cadenas carbonadas con C12, C14, C16 y C18 átomos de carbono.
    Se determinaron la tensión superficial e interfacial, el punto de Krafft, el tiempo humectante, el poder de emulsionamiento, la altura espumante y la concentración critica de miscela (cmc y se hizo un estudio comparativo entre la estructura química y sus propiedades tensioactivas. Se determinó también la actividad antimicrobiana de estos tensioactivos. Estas estructuras se caracterizaron por microanálisis, infrarrojo (IR y resonancia magnética nuclear (RMN.

  14. Clinical comparative study of the effectiveness of and tooth sensitivity to 10% and 20% carbamide peroxide home-use and 35% and 38% hydrogen peroxide in-office bleaching materials containing desensitizing agents.

    Science.gov (United States)

    Basting, R T; Amaral, F L B; França, F M G; Flório, F M

    2012-01-01

    The aim of this study was to compare the effectiveness of and tooth sensitivity to 10% and 20% carbamide peroxide (CP) home-use bleaching agents and 35% and 38% hydrogen peroxide (HP) in-office bleaching agents, all of which contain desensitizing agents, in a clinical trial. Four agents were evaluated: 10% CP and 20% CP (Opalescence PF 10% and Opalescence PF 20%, Ultradent, both with 0.5% potassium nitrate and 0.11% fluoride ions), 38% HP (Opalescence Boost PF, Ultradent, with 3% potassium nitrate and 1.1% fluoride ions), and 35% HP (Pola Office, SDI, with potassium nitrate). The initial screening procedure included 100 volunteers, aged 18 to 42, with no previous sensitivity or bleaching treatment and with any tooth shade. Volunteers were randomly assigned among the technique/bleaching agent groups. A run-in period was performed 1 week before the beginning of the bleaching treatment. For the home-use bleaching technique, each volunteer was instructed to dispense gel (10% CP or 20% CP) into the trays and then insert them into his or her mouth for at least two hours per night for three weeks. For the in-office bleaching technique, the bleaching agents (38% HP or 35% HP) were prepared and used following the manufacturer's instructions, with three applications performed in each session. Three sessions were carried out with an interval of seven days between each session. The participants were evaluated before, at one week, two weeks, and three weeks after the beginning of the bleaching treatment, and again one and two weeks after the bleaching treatment ended. A shade guide (Vita Classical, Vita) was used by a blinded examiner to perform shade evaluations before bleaching and two weeks after the end of bleaching. At the time of the shade evaluations, tooth sensitivity was also recorded by asking the volunteers to classify the sensitivity during bleaching treatment as absent, mild, moderate, or severe. The present study found that 13.8% of the volunteers withdrew from

  15. Oxidative degradation of chemical warfare agents in water by bleaching powder.

    Science.gov (United States)

    Qi, Lihong; Zuo, Guomin; Cheng, Zhenxing; Zhu, Haiyan; Li, Shanmao

    2012-01-01

    Degradation of sulfur mustard (HD), S-2-(di-isopropylamino)ethyl O-ethyl methylphosphonothioate (VX) and Soman (GD) in water by bleaching powder was investigated. The degradation products were comprehensively analyzed by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and ion chromatography. Degradation pathways were deduced based on the identified products. The product analysis results indicated that HD could be degraded through oxidation and chlorination reactions, and a small portion of sulfur atoms could be mineralized into SO(4)(2-) ion. Oxidative degradation of VX could finally generate O-ethyl methylphosphonate acid (EMPA), sulfonic acids, SO(4)(2-) and NO(3)(-) ions. GD would be converted into non-toxic pinacolyl methylphosphonate via nucleophilic substitution.

  16. [Conservative treatment improved corrosive esophagitis and pneumomediastinum in a patient who ingested bleaching agent containing sodium hypochlorite and sodium hydroxide].

    Science.gov (United States)

    Nakano, Hiroshi; Iseki, Ken; Ozawa, Akiko; Tominaga, Aya; Sadahiro, Ryoichi; Otani, Koichi

    2014-03-01

    A 69-year-old man was admitted to the emergency department 3 hours after ingestion of a bleaching agent containing hypochlorous acid and sodium hydroxide in a suicide attempt. Enhanced chest computed tomography scans taken on admission indicated an edematous esophagus and air bubbles in the mediastinum. He underwent endotracheal intubation and mechanical ventilation until day 9 because of laryngeal edema. On day 10, his endoscopy indicated diffuse reddish mucosal hyperemia, erosions, and lacerated mucosal lesions in the esophagus that were indicative of grade 2b corrosive esophagitis. Treatment with a proton pump inhibitor was initiated, with which the condition of the esophagus improved, and on day 44, a slight stricture of the upper part of the esophagus was observed. He was discharged on day 64 without any complaints. The ingestion of sodium hypochlorite induces corrosive esophagitis and acute phase of gastritis. Ingestion of any corrosive agent is known as a risk factor for esophagus cancer in the long-term. In such cases with esophageal stricture, esophagectomy is recommended for preventing esophagus cancer. Considering the age of the patient, however, he did not undergo esophagectomy.

  17. Bleaching of the discolored traumatized tooth

    DEFF Research Database (Denmark)

    Dahl, Jon E.; Kopperud, Siemen E.; Pallesen, Ulla

    2017-01-01

    This chapter focuses on the treatment of discolored traumatized teeth, most of them being non-vital and subsequently, endodontically treated. Tooth bleaching based upon hydrogen peroxide as the active agent, applied directly or produced in a chemical reaction from sodium perborate or carbamide pe...... retreatment....

  18. Beta-ionone activates and bleaches visual pigment in salamander photoreceptors.

    Science.gov (United States)

    Isayama, Tomoki; McCabe England, S L; Crouch, R K; Zimmerman, A L; Makino, C L

    2009-01-01

    Vision begins with photoisomerization of 11-cis retinal to the all-trans conformation within the chromophore-binding pocket of opsin, leading to activation of a biochemical cascade. Release of all-trans retinal from the binding pocket curtails but does not fully quench the ability of opsin to activate transducin. All-trans retinal and some other analogs, such as beta-ionone, enhance opsin's activity, presumably on binding the empty chromophore-binding pocket. By recording from isolated salamander photoreceptors and from patches of rod outer segment membrane, we now show that high concentrations of beta-ionone suppressed circulating current in dark-adapted green-sensitive rods by inhibiting the cyclic nucleotide-gated channels. There were also decreases in circulating current and flash sensitivity, and accelerated flash response kinetics in dark-adapted blue-sensitive (BS) rods and cones, and in ultraviolet-sensitive cones, at concentrations too low to inhibit the channels. These effects persisted in BS rods even after incubation with 9-cis retinal to ensure complete regeneration of their visual pigment. After long exposures to high concentrations of beta-ionone, recovery was incomplete unless 9-cis retinal was given, indicating that visual pigment had been bleached. Therefore, we propose that beta-ionone activates and bleaches some types of visual pigments, mimicking the effects of light.

  19. Differential coral bleaching-Contrasting the activity and response of enzymatic antioxidants in symbiotic partners under thermal stress.

    Science.gov (United States)

    Krueger, Thomas; Hawkins, Thomas D; Becker, Susanne; Pontasch, Stefanie; Dove, Sophie; Hoegh-Guldberg, Ove; Leggat, William; Fisher, Paul L; Davy, Simon K

    2015-12-01

    Mass coral bleaching due to thermal stress represents a major threat to the integrity and functioning of coral reefs. Thermal thresholds vary, however, between corals, partly as a result of the specific type of endosymbiotic dinoflagellate (Symbiodinium sp.) they harbour. The production of reactive oxygen species (ROS) in corals under thermal and light stress has been recognised as one mechanism that can lead to cellular damage and the loss of their symbiont population (Oxidative Theory of Coral Bleaching). Here, we compared the response of symbiont and host enzymatic antioxidants in the coral species Acropora millepora and Montipora digitata at 28°C and 33°C. A. millepora at 33°C showed a decrease in photochemical efficiency of photosystem II (PSII) and increase in maximum midday excitation pressure on PSII, with subsequent bleaching (declining photosynthetic pigment and symbiont density). M. digitata exhibited no bleaching response and photochemical changes in its symbionts were minor. The symbiont antioxidant enzymes superoxide dismutase, ascorbate peroxidase, and catalase peroxidase showed no significant upregulation to elevated temperatures in either coral, while only catalase was significantly elevated in both coral hosts at 33°C. Increased host catalase activity in the susceptible coral after 5days at 33°C was independent of antioxidant responses in the symbiont and preceded significant declines in PSII photochemical efficiencies. This finding suggests a potential decoupling of host redox mechanisms from symbiont photophysiology and raises questions about the importance of symbiont-derived ROS in initiating coral bleaching.

  20. Etiology and prevention of external cervical root resorption associated to teeth bleaching

    Directory of Open Access Journals (Sweden)

    Eliane Mendes da SILVA

    2010-03-01

    Full Text Available Introduction and objective: Esthetic dentistry has been prioritizedand the desire for whiter teeth has been increasingly present in dental offices, since whiter teeth tend to indicate health, beauty, youth and a more attractive smile. Teeth bleaching is a conservative method widely used to restore the original color of darkened teeth. However, possible relations with the external cervical root resorption have concerned many researchers and clinicians. Literature review: There are many mechanisms that can activate the external cervical root resorption, such as: chemical and physical action of the bleaching materials used, morphology of the cementoenamel junction associated to the immune system, material concentration, traumas and bleaching technique used. Conclusion: Therefore, considering many factors that are still not conclusive, preventing deleterious effects on teeth and support structures, care must be taken when choosing bleaching agent and bleaching technique, as well as when selecting each case, beyond a proper restoration after teeth bleaching.

  1. 阳离子明胶蛋白助剂与TAED在棉织物双氧水漂白中应用效果比较%Comparative study on application of cationic gelatin protein agent and TAED in cotton fabric bleaching

    Institute of Scientific and Technical Information of China (English)

    唐俊玲; 王雪燕

    2015-01-01

    将自制阳离子明胶蛋白助剂与商品漂白活化剂四乙酰乙二胺(TAED)分别加入到双氧水漂白浴中,构建新的漂白体系。对比这2种新漂白体系漂白处理棉织物的白度、毛效、强力以及染色效果,并与传统漂白织物进行比较。结果表明,阳离子明胶蛋白助剂是一种比商品漂白活化剂TAED应用性能更好的助剂,不仅有利于促进双氧水漂白,而且能提高漂白织物的毛效和染色性能。%A self-made cationic gelatin protein agent and a commercial bleaching activator tetraacetyleth⁃ylenediamine (TAED) were added to the hydrogen peroxide bleaching bath respectively, then two new bleach⁃ing systems were set up. Whiteness, capil ary effect, strength and dyeing effect of cotton fabric treated by the new bleaching systems and traditional system were compared. The results showed that the cationic gela⁃tin protein agent was better than commercial bleaching activator TAED in application, it was not only beneficial to promote the effect of hydrogen peroxide bleaching, but also improve the capil ary effect and dyeing perfor⁃mances of bleached cotton fabric.

  2. A review of the effect of tooth bleaching agents on oral microbes%牙齿美白剂对口腔微生物影响的研究进展

    Institute of Scientific and Technical Information of China (English)

    张博; 霍思蓓; 刘诗雨; 李明云

    2016-01-01

    牙齿美白剂中含有强氧化剂,可产生有效的漂白作用,是牙齿美白剂的主要组成部分.牙齿美白剂是否会增加龋易感性是众多研究者一直关注的问题.因此,本文针对美白剂对口腔致龋微生物浮游状态生长及生物膜形成的影响进行综述,以期为今后相关研究提供参考.%Tooth bleaching agents contain powerful oxidizing agents,which serve as the main part of bleaching agents because of its release of effective bleaching component.It has been a hot topic whether tooth bleaching agents exert negative influence on oral health.In order to provide train of thoughts and reference for further clinical researches and treatments,this review paper focuses on bleaching agents' effects on the growth of oral microbes and the formation of biofilms.

  3. Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology Efeitos de agentes clareadores à base de peróxidos na microdureza, rugosidade e morfologia superficial do esmalte

    Directory of Open Access Journals (Sweden)

    Cristiane Franco Pinto

    2004-12-01

    Full Text Available The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment. Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11: control, Whiteness Perfect - 10% carbamide peroxide (10% CP, Colgate Platinum - 10% CP, Day White 2Z - 7.5% hydrogen peroxide (7.5% HP, Whiteness Super - 37% CP, Opalescence Quick - 35% CP and Whiteness HP - 35% HP. Bleaching agents were applied according to manufacturers' instructions. The control group remained not treated and stored in artificial saliva. Microhardness testing was performed with a Knoop indentor and surface roughness was analyzed with a profilometer. Morphologic observations were carried out with scanning electron microscopy (SEM. Results were statistically analyzed by two-way analysis of variance and Tukey's test (5%, and revealed a significant decrease in microhardness values and a significant increase in surface roughness post-bleaching. Changes in enamel morphology after bleaching were observed under SEM. It was concluded that bleaching agents can alter the microhardness, roughness and morphology of dental enamel surface.O objetivo deste estudo foi avaliar a rugosidade, microdureza e morfologia superficial do esmalte dental humano tratado com seis agentes clareadores (antes e depois do tratamento. Amostras de esmalte dental humano foram obtidas de terceiros molares e aleatoriamente distribuídas em sete grupos (n = 11: controle, Whiteness Perfect - peróxido de carbamida a 10% (PC 10%, Colgate Platinum - PC 10%, Day White 2Z - peróxido de hidrogênio a 7,5% (PH 7,5%, Whiteness Super - PC 37%, Opalescence Quick - PC 35% e Whiteness HP - PH 35%. Os agentes clareadores foram aplicados de acordo com as instruções dos fabricantes. O grupo controle permaneceu sem tratamento e armazenado em saliva artificial. O teste de microdureza foi realizado

  4. The effect of combined bleaching techniques on oral microbiota

    Directory of Open Access Journals (Sweden)

    Franz-Montan Michelle

    2009-01-01

    Full Text Available Aims : To evaluate the antimicrobial activity of 10% and 37% carbamide peroxide during dental bleaching in three different modes. Materials and Methods : This five-week double-blind randomized controlled trial included 32 volunteers assigned to four groups (n = 8. Each group received bleaching agents or placebo as an in-office and at-home treatment. The dental bleaching techniques were: In-office bleaching (37% carbamide peroxide: CP37; at-home bleaching (10% carbamide peroxide: CP10 and the association of both (CP37 and CP10. Saliva samples were collected right before (baseline, right after, 12 hours after, and seven days after the treatment. Counts of total microorganisms, Streptococci, and Mutans streptococci were carried out. Friedman test (α = 0.05 was used to compare the microorganism counts. Results : The number of the all oral microorganisms remained stable during all experiment. Conclusions : No bleaching agent (CP37, CP10 or the combination of both was able to reduce the oral microorganisms tested.

  5. Active radiation hardening of Tm-doped silica fiber based on pump bleaching.

    Science.gov (United States)

    Xing, Ying-bin; Zhao, Nan; Liao, Lei; Wang, Yi-bo; Li, Hai-qing; Peng, Jing-gang; Yang, Lv-yun; Dai, Neng-li; Li, Jin-yan

    2015-09-21

    Tm-doped fiber laser or amplifier can be applied in varied adverse environments. In this work, we demonstrate the pump bleaching of Tm-doped silica fiber with 793nm pump source under gamma-ray irradiation in the range 50Gy-675Gy. The recovery time, the fiber slope efficiency and the fiber cladding absorption spectra after irradiation and bleaching have been measured. It is found that the recovery time and radiation induce absorption are positively associated with doses, however, the fiber slope efficiency of irradiated TDF and bleached TDF are both negatively correlated with doses. Based on the simulation of the fiber core temperature, the probable mechanism of pump bleaching is also discussed.

  6. Application of a New Chelating Agent in Deinked Pulp Bleaching%新型螯合剂用于废纸脱墨浆的漂白

    Institute of Scientific and Technical Information of China (English)

    张海潮; 胡可信; 余聪

    2011-01-01

    采用柠檬酸钠、Na2SiO3对废纸脱墨浆进行预处理,并与EDTA预处理进行比较。结果表明,柠檬酸钠可替代EDTA作为纸浆漂白的螯合剂,废纸脱墨浆柠檬酸钠预处理的最佳工艺条件为:柠檬酸钠用量0.8%、预处理时间30min、预处理温度70℃、pH值8。采用柠檬酸钠预处理,并经过氧化氢一甲眯亚磺酸两段漂白,漂后纸浆白度可达77.67%ISO。%The sodium citrate and sodium silicate were used as another kind of chelating agent for the pre-treatment of DIP, which would be bleached by FAS(F) later, then contrasted with the chelation of EDTA. The results showed that the sodium citrate can be used as a chelating agent in place of EDTA. The optimum conditions for the pretreatment of DIP by the sodium citrate are as follows, sodium citrate dosage 0.8%, pre-treated time 30 min, pre-treated temperature 70℃, pH 8. By using the Sodium Citrate as the chelating agent, after the two-stage bleaching of P-F, the brightness of DIP could reach 77.67% (ISO).

  7. Bleaching in coral reef anthozoans: effects of irradiance, ultraviolet radiation, and temperature on the activities of protective enzymes against active oxygen

    Science.gov (United States)

    Lesser, M. P.; Stochaj, W. R.; Tapley, D. W.; Shick, J. M.

    1990-04-01

    Recent widespread bleaching of coral reef anthozoans has been observed on the Great Barrier Reef, the Pacific coast of Panama, and in the Caribbean Sea. Bleaching events have been correlated with anomalously high sea surface temperatures which are presumed to cause the expulsion of zooxanthellae from their hosts. Our experimental results show that increases in temperature significantly reduce the total number of zooxanthellae per polyp. At the same time temperature, irradiance (photosynthetically active radiation=PAR), and ultraviolet radiation (UV) independently increase the activities of the enzymes superoxide dismutase, catalase, and ascorbate peroxidase within the zooxanthellae of the zoanthid Palythoa caribaeorum. Enzyme activities within the host are only suggestive of similar changes. These enzymes are responsible for detoxifying active forms of oxygen, and their elevated activities indirectly indicate an increase in the production of active oxygen species by increases in these environmental factors. Historically, bleaching has been attributed to changes in temperature, salinity, and UV. Increases in temperature or highly energetic UV radiation can increase the flux of active forms of oxygen, particularly at the elevated oxygen concentrations that prevail in the tissues during photosynthesis, with oxygen toxicity potentially mediating the bleaching event. Additionally, the concentration of UV absorbing compounds within the symbiosis is inversely related to temperature, potentially increasing exposure of the host and zooxanthellae to the direct effects of UV.

  8. 棉针织物低温练漂助剂的开发及应用%Development and application of low temperature scouring and bleaching agent of cotton knits

    Institute of Scientific and Technical Information of China (English)

    孙洁

    2014-01-01

    The souring agent XS-810 and activator XS-812 were developed for application in cotton knits with low temperature scouring and bleaching. The optimum amount of agents determined through orthogonal experiment was 30%H2O2 6 g/L, XS-810 2.5 g/L, XS-812 1 g/L, and the process of low temperature scouring and bleaching was provided. The results showed that the whiteness of cotton knits with the low temperature pretreating was above 77%, capillary effect was 14.4 cm/30 min, and bursting strength reduced less than 5%. The whiteness, bursting strength andK/S of dyed fabrics were higher than those treated by conventional process. Moreover, the low temperature pretreating process can save energy and reduce pollution.%开发了应用于棉针织物低温练漂的精练剂XS-810和活化剂XS-812。通过正交试验优化了各助剂的最佳用量:30%H2O26 g/L,XS-8102.5 g/L, XS-8121 g/L,并给出了低温练漂的推荐工艺。结果表明,通过低温前处理的棉针织物白度大于77%,毛效为14.4 cm/30 min,顶破强力降低率小于5%,白度、顶破强力及染色织物的K/S值均较传统工艺练漂的织物略高,且低温前处理工艺节约能耗,降低污染。

  9. Effect of different bleaching strategies on microhardness of a silorane-based composite resin

    Science.gov (United States)

    Bahari, Mahmoud; Savadi Oskoee, Siavash; Mohammadi, Narmin; Ebrahimi Chaharom, Mohammad Esmaeel; Godrati, Mostafa; Savadi Oskoee, Ayda

    2016-01-01

    Background. Dentists’ awareness of the effects of bleaching agents on the surface and mechanical properties of restorative materials is of utmost importance. Therefore, this in vitro study was undertaken to investigate the effects of different bleaching strategies on the microhardness of a silorane-based composite resin. Methods. Eighty samples of a silorane-based composite resin (measuring 4 mm in diameter and 2 mm in thickness) were prepared within acrylic molds. The samples were polished and randomly assigned to 4 groups (n=20). Group 1 (controls) were stored in distilled water for 2 weeks. The samples in group 2 underwent a bleaching procedure with 15% carbamide peroxide for two weeks two hours daily. The samples in group 3 were bleached with 35% hydrogen peroxide twice 5 days apart for 30 minutes each time. The samples in group 4 underwent a bleaching procedure with light-activated 35% hydrogen peroxide under LED light once for 40 minutes. Then the microhardness of the samples was determined using Vickers method. Data were analyzed with one-way ANOVA and post hoc Tukey tests (P 0.05). Conclusion. Bleaching agents decreased microhardness of silorane-based composite resin restorations, the magnitude of which depending on the bleaching strategy used. PMID:28096946

  10. Skin Bleaching

    OpenAIRE

    Ahmed, Samira M.

    2015-01-01

    In this project, I aim to investigate the reasoning behind the practice of skin bleaching by analyzing the documentary ”Dark Girls”, to gain a better understanding of race and colorism issues. Also this project tries to see if there is a connection with history and if this has been a part of making the european beauty ideal determine the choices black’s make in regards to beauty.

  11. Response surface modeling of acid activation of raw diatomite using in sunflower oil bleaching by: Box-Behnken experimental design.

    Science.gov (United States)

    Larouci, M; Safa, M; Meddah, B; Aoues, A; Sonnet, P

    2015-03-01

    The optimum conditions for acid activation of diatomite for maximizing bleaching efficiency of the diatomite in sun flower oil treatment were studied. Box-Behnken experimental design combining with response surface modeling (RSM) and quadratic programming (QP) was employed to obtain the optimum conditions of three independent variables (acid concentration, activation time and solid to liquid) for acid activation of diatomite. The significance of independent variables and their interactions were tested by means of the analysis of variance (ANOVA) with 95 % confidence limits (α = 0.05). The optimum values of the selected variables were obtained by solving the quadratic regression model, as well as by analyzing the response surface contour plots. The experimental conditions at this global point were determined to be acid concentration = 8.963 N, activation time = 11.9878 h, and solid to liquid ratio = 221.2113 g/l, the corresponding bleaching efficiency was found to be about 99 %.

  12. Activity Recognition for Agent Teams

    Science.gov (United States)

    2007-07-01

    seek to use in the upcoming confrontation. There is not a simple mapping between a character capabilities and this policy; an effective team role must...additional research challenges, specific to the team role assumed by the agent. Agents that support individual human team members face the following chal

  13. Bleaching of optical activity induced by UV Laser exposure in natural silica

    OpenAIRE

    Cannas, M.; Messina, F.

    2004-01-01

    We report experimental data on two types of natural silica, differing for their OH content, irradiated with UV photons (4.66 eV) from a pulsed Nd:YAG laser. Irradiation induces a reduction of the absorption band at 5.12eV and of the associated emissions at 3.14eV and 4.28eV, ascribed to twofold coordinated Ge (=Ge'') centers pre-existing in our samples. The bleaching is mainly due to the post-irradiation conversion of =Ge'' into the paramagnetic H(II) center via trapping of a H atom. Comparis...

  14. Lipase-catalyzed production of biodiesel fuel from vegetable oils contained in waste activated bleaching earth

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro, Ana V. Lara; Park, Enoch Y. [Shizuoka Univ., Dept. of Applied Biological Chemistry, Shizuoka (Japan)

    2003-02-28

    Waste bleaching earths from crude vegetable oil refining process contain approximately 40% of its weight as oil. Low valued oils are potential substrates for biodiesel fuel production. Vegetable oils from waste bleaching earth samples were organic-solvent extracted and identified as soybean, palm and rapeseed oil. Methanolysis was efficiently catalyzed by Rhizopus oryzae lipase in the presence of high water content, and by a single addition of methanol. R. oryzae lipase was not inactivated by methanol in concentrations lower than 4 milli-equivalents and 75% water content. Optimum conditions for methanolysis of extracted oils were 75% water content (by weight of substrate), an oil/methanol molar ratio of I:4, and 67 IU/g of substrate with agitation at 175 rpm for 96 h at 35 deg C. The highest conversion yield reached 55% (w/w) with palm oil after 96 h of reaction. Adverse viscosity conditions might have influenced methanolysis of extracted soybean and rapeseed oil in spite of high water or methanol concentrations. (Author)

  15. Inhibition of photosynthetic CO₂ fixation in the coral Pocillopora damicornis and its relationship to thermal bleaching.

    Science.gov (United States)

    Hill, Ross; Szabó, Milán; ur Rehman, Ateeq; Vass, Imre; Ralph, Peter J; Larkum, Anthony W D

    2014-06-15

    Two inhibitors of the Calvin-Benson cycle [glycolaldehyde (GA) and potassium cyanide (KCN)] were used in cultured Symbiodinium cells and in nubbins of the coral Pocillopora damicornis to test the hypothesis that inhibition of the Calvin-Benson cycle triggers coral bleaching. Inhibitor concentration range-finding trials aimed to determine the appropriate concentration to generate inhibition of the Calvin-Benson cycle, but avoid other metabolic impacts to the symbiont and the animal host. Both 3 mmol l(-1) GA and 20 μmol l(-1) KCN caused minimal inhibition of host respiration, but did induce photosynthetic impairment, measured by a loss of photosystem II function and oxygen production. GA did not affect the severity of bleaching, nor induce bleaching in the absence of thermal stress, suggesting inhibition of the Calvin-Benson cycle by GA does not initiate bleaching in P. damicornis. In contrast, KCN did activate a bleaching response through symbiont expulsion, which occurred in the presence and absence of thermal stress. While KCN is an inhibitor of the Calvin-Benson cycle, it also promotes reactive oxygen species formation, and it is likely that this was the principal agent in the coral bleaching process. These findings do not support the hypothesis that temperature-induced inhibition of the Calvin-Benson cycle alone induces coral bleaching.

  16. Kraft pulp bleaching with molybdenum activated acid peroxide (P{sub Mo} stage); Branqueamento de polpa celulosica kraft de eucalipto com peroxido acido ativado por molibdenio

    Energy Technology Data Exchange (ETDEWEB)

    Rabelo, Marcos Sousa [Servico Nacional de Aprendizagem Industrial (SENAI), Lauro de Freitas, BA (Brazil). Dept. Regional da Bahia; Silva, Vanessa Lopes; Barros, Denise Pires de; Colodette, Jorge Luiz [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Engenharia Florestal; Sacon, Vera Maria; Silva, Marcelo Rodrigues da [Votorantim Celulose e Papel, Jacarei, SP (Brazil)

    2009-07-01

    Optimum conditions to run the P{sub Mo} stage for bleaching eucalyptus kraft pulp were 90 deg C, pH 3.5, 2 h, 0.1 kg/t Mo and 5 kg/t H{sub 2}O{sub 2}. The P{sub Mo} stage efficiency increased with decreasing pH (1.5-5.5) and increasing temperature (75-90 deg C), time (2-4 h), and hydrogen peroxide (3-10 kg/t) and molybdenum concentration (0.1-0.4 kg/t). The implementation of the P{sub Mo} stage, as replacement for the A stage, decreased total active chlorine demand of the OAZDP sequence by 6 kg/t to reach 90% ISO, both in laboratory and mill scale. Such practice resulted in decreased bleaching chemical costs to produce fully bleached pulp of 90% ISO. (author)

  17. Active evacuation guidance using sensor agent robot

    Science.gov (United States)

    Ise, Daiki; Mita, Akira

    2012-04-01

    Evacuation systems for buildings are designed based on event scenarios, so they are not prepared for unexpected events that are not included in the scenarios. In this paper, we propose a new active evacuation guidance system using sensor agent robots. We first introduce a Structural Health Monitoring (SHM) system to be used in conjunction with sensor agent robots for active evacuation guidance. Then the role of sensor agent robots is explained. An algorithm to immediately access the safety of the building after a large earthquake is also proposed using only the information taken by a sensor agent robot.

  18. Effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP and fluoride on the microhardness of enamel treated with a bleaching agent: ex vivo

    Directory of Open Access Journals (Sweden)

    Mügem Aslı Gürel Ekici

    2017-05-01

    Full Text Available Objective: The aim of this study was to compare the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP and 1.23% acidulated phosphate fluoride (APF; pH 3.5 on the microhardness of enamel treated with a bleaching agent. Materials and Method: Enamel slices (n=32; 2×4 mm were obtained from 8 mandibular permanent molar teeth. Specimens were embedded into acrylic resin blocks with the enamel surfaces facing upwards. Vickers microhardness (VHN values of the specimens were recorded at baseline. The specimens were randomly divided into 4 experimental groups, and the experimental designation was as follows: Group 1: no treatment (control, Group 2: 35% hydrogen peroxide (HP, Group 3: HP + CPP-ACP, Group 4: HP + APF application. After treatments, VHN values were measured and recorded again. Specimens were stored in artificial saliva at 37 °C for 1 week. After 1 week second application was done and VHN of the specimens was registered once more. Data were statistically analyzed with ANOVA and Tukey post hoc tests. Values obtained at baseline, and first and second applications were compared using paired samples t-test (α=0.05. Results: In inter-group comparisons, no statistically significant difference in the enamel microhardness values was found between the baseline, and first and second applications (p>0.05. In intra-group comparisons, again, no statistically significant difference in the enamel microhardness values was found between the baseline, and first and second applications (p>0.05. Conclusion: According to the limitations of this study it can be concluded that neither the HP application nor the CPP-ACP or APF application after HP had any significant effect on the enamel microhardness.

  19. Scheduling Activity in an Agent Architecture

    OpenAIRE

    Soto, Ignacio

    2000-01-01

    Agents for applications in dynamic environments require artificial intelligence techniques to solve problems to achieve their objectives. For example, they must develop plans of actions to carry out missions in their environment, in other words, to achieve some state in the world. But also, the agents must fulfill real-time requirements that arise because the characteristics of the applications and the dynamism of the environment. In this paper we analyze the use of a schedule of activity in ...

  20. Anaphylaxis, contact urticaria, and allergic asthma caused by persulfates in hair bleaching products

    NARCIS (Netherlands)

    Hoekstra, Miriam; Schuttelaar, M.L.; Coenraads, P.J.

    2010-01-01

    Background: Persulfate salts are potent oxidizing agents in hair bleach products that accelerate the bleaching process. Ammonium and potassium persulfates may cause delayedtype and immediate skin reactions. Also allergic asthma and rhinitis have been described. Objectives: Ammonium and potassium per

  1. Enzymatic Method for Rapid Determination of Oxalic Acid in Bleaching Filtrates from the Pulp and Paper Industry

    Institute of Scientific and Technical Information of China (English)

    HONG Feng; SJ(O)DE Anders; NILVEBRANT Nils-Olof; J(O)NSSON Leif J.

    2005-01-01

    Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry.Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method.Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching filtrates from the pulp and paper industry. The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.

  2. Photothermal bleaching in time-lapse photoacoustic microscopy

    OpenAIRE

    Gao, Liang; Wang, Lidai; Li, Chiye; Garcia-Uribe, Alejandro; Lihong V. Wang

    2012-01-01

    We studied the phenomenon of photothermal bleaching — a gradual reduction of contrast agent particles during repeated scans in photoacoustic microscopy. The dependence of the photothermal bleaching rate on the excitation pulse energy, pulse duration, and the absorber’s size was determined while the laser focal diameter was held constant. Our results showed that, the dependence of the photothermal bleaching rate on the excitation pulse energy differed before and after the absorbers were raised...

  3. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

    2005-01-01

    Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning El...

  4. Adsorption of emulsified oil from metalworking fluid on activated bleaching earth-chitosan-SDS composites: Optimization, kinetics, isotherms.

    Science.gov (United States)

    Naowanat, Nitiya; Thouchprasitchai, Nutthavich; Pongstabodee, Sangobtip

    2016-03-15

    The adsorption of emulsified oil from metalworking fluid (MWF) on activated bleaching earth (BE)-chitosan-sodium dodecyl sulfate (SDS) composites (BE/MCS) was investigated under a statistical design of experiments at a 95% confidence interval to identify the critical factors and to optimize the adsorption capacity. The BE/MCS adsorbents were characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller adsorption/desorption isotherms, contact angle analysis (sessile drop technique) and their zeta potential. From the results of a full 2(5) factorial design with three center points, the adsorbent weight and initial pH of the MWF had a significant antagonistic effect on the adsorption capacity while the initial MWF concentration and BE:chitosan:SDS weight ratio had a synergistic influence. Temperature factor has no discernible effect on the capacity. From the FCCC-RSM design, the optimal capacity range of 2840-2922.5 mg g(-1) was achieved at sorbent weight of 1.6-1.9 g, pH of 5.5-6.5, initial MWF concentration of 52-55 g l(-1) and BE:chitosan:SDS (w/w/w) ratio of 4.7:1:1-6.2:1:1. To test the validation and sensitivity of RSM model, the results showed that the estimated adsorption capacity was close to the experimental capacity within an error range of ±3%, suggesting that the RSM model was acceptable and satisfied. From three kinetics models (pseudo-first-order, pseudo-second-order model and Avrami's equation) and two adsorption isotherms (Langmuir model and Freundlich model), assessed using an error function (Err) and the coefficient of determination (R(2)), Avrami's equation and Freundlich isotherm model provided a good fitting for the data, suggesting the presence of more than one reaction pathway in the MWF adsorption process and the heterogeneous surface adsorption of the BC/ABE-5.5 composite.

  5. 高岭土还原络合漂白工艺中络合剂的选择%Selection of Complexing Agent for Technology of Reducting and Complexing Bleach of Kaolin

    Institute of Scientific and Technical Information of China (English)

    夏光华; 王振华; 苏小丽

    2011-01-01

    Using the Beihai kaolin as raw material, thiourea dioxide as reducing agent,selected several different kinds of eomplexing agents ( humic acid, triethanolamine, sodium tripolyphosphate, citric acid and EDTA), investigated the complexation under different conditions on redueting and eomplexing bleach of kaolin. The results showed that the whiteness after calcination ( 1200 ℃ ) of kaolin after the blank experiments increased from 83% to about 86%. All complexing agent can strengthen the bleaching in this experiments,the humie acid, triethanolamine, EDTA achieved better effectiveness, when the dosage is 0.3%, the whiteness after calcination ( 1200 ℃ ) of kaolin after the bleaching increased up to 88%.In the united optimum conditions,that is, the dosage of triethanolamine 0.5% ,pH value of slurry 7.5,pulp density 20%, reaction time lb, the whiteness after calcination (1200 ℃ ) of kaolin increased up to 89%.%以广西北海地区高岭上为原料,二氧化硫脲为还原剂,选取几种不同种类的络合剂(腐植酸,三乙醇胺,三聚磷酸钠,柠檬酸和EDTA),考察了它们在高岭士还原络合漂白工艺中的络合作用.结果表明:不加络合剂的空白试验可使漂白后高岭土的煅烧白度由83%增加到86%.加入络合剂后对漂白均起到了强化效果,其中腐植酸,三乙醇胺,EDTA在用量为0.3%时,町使漂白后高岭土的煅烧白度达到88%.三乙醇胺在投加量为0.5%,矿浆pH值为7.5,矿浆浓度为20%,反应时间为1h时,可使漂白后高岭上的煅烧白度达纠89%左右.

  6. Effectiveness of different carbamide peroxide concentrations used for tooth bleaching: an in vitro study

    Directory of Open Access Journals (Sweden)

    Sônia Saeger Meireles

    2012-04-01

    Full Text Available OBJECTIVES: This in vitro study evaluated the effectiveness of three carbamide peroxide concentrations used for tooth bleaching treatments. MATERIAL AND METHODS: Sixty bovine dental slabs (6x6x3 mm were obtained, sequentially polished, submitted to artificial staining (baseline and randomized into four groups (n=15, according to the bleaching agent concentration: distilled water (control, 10% (CP10, 16% (CP16 or 37% (CP37 carbamide peroxide. CP10 and CP16 were covered with 0.2 mL of the respective bleaching gels, which were applied on enamel surface for 4 h/day during two weeks. Samples of CP37 were covered with 0.2 mL of the bleaching gel for 20 min. The gel was light activated by two 40-s applications spaced by 10-min intervals. The gel was renewed and applied 3 times per clinical session. This cycle was repeated at 3 sessions with 5 days of interval between them. Tooth shade evaluations were done with a digital spectrophotometer at T0 (baseline, T1 (after 1-week of treatment and T2 (1-week post-bleaching. Tooth shade means were statistically analyzed by Kruskal-Wallis and Friedman's tests and color parameters were analyzed by two-way ANOVA and Tukey's test (p0.05. CONCLUSIONS: One week after the end of the treatment, all carbamide peroxide concentrations tested produced similar tooth color improvement.

  7. Influence of whitening gel on pulp chamber temperature rise by in-office bleaching technique

    Directory of Open Access Journals (Sweden)

    Sandro Cordeiro Loretto

    Full Text Available INTRODUCTION: Dental bleaching is a conservative method for the aesthetic restoration of stained teeth. However, whitening treatments are likely to cause adverse effects when not well planned and executed. OBJECTIVE: This study evaluated the influence of whitening gel on temperature rise in the pulp chamber, using the in-office photoactivated dental bleaching technique. MATERIAL AND METHOD: The root portion of an upper central human incisor was sectioned 3mm below the cemento-enamel junction. The root canal was enlarged to permit the insertion of the K-type thermocouple sensor (MT-401 into the pulp chamber, which was filled with thermal paste to facilitate the transfer of heat during bleaching. Three photosensitive whitening agents (35% hydrogen peroxide were used: Whiteness HP (FGM, Whiteness HP Maxx (FGM and Lase Peroxide Sensy (DMC. An LED photocuring light (Flash Lite - Discus Dental was used to activate the whitening gels. Six bleaching cycles were performed on each group tested. The results were submitted to one-way ANOVA and LSD t-test (α<0.05. RESULT: The lowest mean temperature variation (ºC was detected for Lase Peroxide Sensy (0.20, while the highest was recorded for Whiteness HP (1.50. CONCLUSION: The Whiteness HP and Whiteness HP Maxx whitening gels significantly affected the temperature rise in the pulp chamber during bleaching, and this variation was dependent on the type of whitening gel used.

  8. Randomized controlled trial of sealed in-office bleaching effectiveness.

    Science.gov (United States)

    Santana, Mário Artur Pereira; Nahsan, Flávia Pardo Salata; Oliveira, Alaíde Hermínia de Aguiar; Loguércio, Alessandro Dourado; Faria-e-Silva, André Luis

    2014-01-01

    Regardless of the high success rate, patients commonly report the occurrence of tooth sensitivity during the in-office bleaching procedures. Recently, it has been demonstrated that using a customized tray (called sealed in-office bleaching technique) reduces peroxide penetration. The aim of this randomized clinical study was to evaluate tooth sensitivity and bleaching efficacy of sealed bleaching, in comparison with a conventional in-office technique. Twenty patients were randomized allocated in two groups in which 35% hydrogen peroxide gel was used in a single 45-min application. For the sealed technique, a customized bleaching tray was fabricated and carefully positioned over the bleaching agent during the session. The color was recorded at a baseline, 7 and 28 days after the bleaching session, using Vita Easy Shade spectrophotometer. Tooth sensitivity was recorded during (20 and 40 min) and immediately after the treatment using a visual analogue scale. The bleaching efficacy was evaluated by repeated-measures ANOVA, while the absolute risk of tooth sensitivity and its intensity were evaluated by Fisher's exact and Mann-Whitney tests, respectively (α=0.05). No significant difference on bleaching efficacy was observed between the conventional (7.4 and 8.1 ΔE) and sealed techniques (7.8 and 8.3 ΔE) at both evaluation periods. No significant difference was observed regarding the absolute risk of tooth sensitivity (p=0.15). Sealed technique showed a significant decrease of sensitivity intensity after 40 min (p=0.03). Sealed bleaching technique was able to reduce the sensitivity intensity during the bleaching procedure, without jeopardizing the bleaching efficacy.

  9. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  10. Neutralization of radical toxicity by temperature-dependent modulation of extracellular SOD activity in coral bleaching pathogen Vibrio shiloi and its role as a virulence factor.

    Science.gov (United States)

    Murali, Malliga Raman; Raja, Subramaniya Bharathi; Devaraj, Sivasitambaram Niranjali

    2010-08-01

    Vibrio shiloi is the first and well-documented bacterium which causes coral bleaching, particularly, during summer, when seawater temperature is between 26 and 31 degrees C. Coral bleaching is the disruption of the symbiotic association between coral hosts and their photosynthetic microalgae zooxanthellae. This is either due to lowered resistance in corals to infection or increased virulence of the bacterium at the higher sea surface temperature. The concentration of the oxygen and resulting oxygen radicals produced by the zooxanthellae during photosynthesis are highly toxic to bacteria, which also assist corals in resisting the infection. Hence, in this study we examined the effect of different temperatures on the activity of a novel extracellular SOD in V. shiloi. We also partially characterized the SOD and clearly confirmed that the extracellular SOD produced by V. shiloi is Mn-SOD type, as it was not inhibited by H2O2 or KCN. Performing chemical susceptibility killing assay, we confirmed that extracellular SOD may act as first line of defense for the bacteria against the reactive oxygen species. Since, increased activity of novel Mn-SOD at higher temperature, leads to the neutralization of radical toxicity and facilitates the survival of V. shiloi. Hence, the extracellular Mn-SOD may be considered as a virulence factor.

  11. Clinical trial evaluating color change and tooth sensitivity throughout and following in-office bleaching.

    Science.gov (United States)

    Machado, Lucas Silveira; de Oliveira, Fernanda Garcia; Rocha, Eduardo Passos; dos Santos, Paulo Henrique; Briso, André Luiz Fraga; Sundefeld, Maria Lúcia Marçal Mazza; Sundfeld, Renato Herman

    2013-01-01

    The aim of this study was to assess the color alteration and sensitivity of teeth throughout and following in-office bleaching. Twenty-two volunteers participated in this clinical trial of bleaching treatment (35% hydrogen peroxide bleaching gel and placebo) applied on maxillary incisors and canines. According to a split-mouth design, the volunteers' maxillary hemi-arches received either the bleaching or placebo agent, applied four times, at 1-week intervals. Color alteration and tooth sensitivity were assessed throughout and following bleaching. Statistical calculations were performed using gamma distribution and repeated-measures ANOVA. There was a statistically significant difference between teeth submitted to a bleaching agent and placebo (P < .001). At the end of the first, second, third, and fourth sessions, the bleached teeth presented color scores statistically lower than those observed immediately before bleaching. There was no difference in the color scale scores of the bleached teeth between bleaching sessions. The sensitivity data test showed a significant difference among treatments (P < .0001). Color alteration and dental sensitivity were altered by the bleaching agent.

  12. Branqueamento de polpa celulósica kraft de eucalipto com peróxido ácido ativado por molibdênio Kraft pulp bleaching with molybdenum activated acid peroxide (P Mo stage

    Directory of Open Access Journals (Sweden)

    Marcos Sousa Rabelo

    2009-01-01

    Full Text Available Optimum conditions to run the P Mo stage for bleaching eucalyptus kraft pulp were 90 ºC, pH 3.5, 2 h, 0.1 kg/t Mo and 5 kg/t H2O2. The P Mo stage efficiency increased with decreasing pH (1.5-5.5 and increasing temperature (75-90 ºC, time (2-4 h, and hydrogen peroxide (3-10 kg/t and molybdenum concentration (0.1-0.4 kg/t. The implementation of the P Mo stage, as replacement for the A stage, decreased total active chlorine demand of the OAZDP sequence by 6 kg/t to reach 90% ISO, both in laboratory and mill scale. Such practice resulted in decreased bleaching chemical costs to produce fully bleached pulp of 90% ISO.

  13. Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins

    Science.gov (United States)

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  14. Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey products

    Science.gov (United States)

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  15. Patterns of coral bleaching: Modeling the adaptive bleaching hypothesis

    Science.gov (United States)

    Ware, J.R.; Fautin, D.G.; Buddemeier, R.W.

    1996-01-01

    Bleaching - the loss of symbiotic dinoflagellates (zooxanthellae) from animals normally possessing them - can be induced by a variety of stresses, of which temperature has received the most attention. Bleaching is generally considered detrimental, but Buddemeier and Fautin have proposed that bleaching is also adaptive, providing an opportunity for recombining hosts with alternative algal types to form symbioses that might be better adapted to altered circumstances. Our mathematical model of this "adaptive bleaching hypothesis" provides insight into how animal-algae symbioses might react under various circumstances. It emulates many aspects of the coral bleaching phenomenon including: corals bleaching in response to a temperature only slightly greater than their average local maximum temperature; background bleaching; bleaching events being followed by bleaching of lesser magnitude in the subsequent one to several years; higher thermal tolerance of corals subject to environmental variability compared with those living under more constant conditions; patchiness in bleaching; and bleaching at temperatures that had not previously resulted in bleaching. ?? 1996 Elsevier Science B.V. All rights reserved.

  16. Comparative clinical study of the effectiveness of different dental bleaching methods - two year follow-up

    Directory of Open Access Journals (Sweden)

    Rafael Francisco Lia Mondelli

    2012-08-01

    Full Text Available This study evaluated color change, stability, and tooth sensitivity in patients submitted to different bleaching techniques. MATERIAL AND METHODS: In this study, 48 patients were divided into five groups. A half-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation: G1: 35% hydrogen peroxide (HP (Lase Peroxide - DMC Equipments, São Carlos, SP, Brazil + hybrid light (HL (LED/Diode Laser, Whitening Lase II DMC Equipments, São Carlos, SP, Brazil; G2: 35% HP; G3: 38% HP (X-traBoost - Ultradent, South Jordan UT, USA + HL; G4: 38% HP; and G5: 15% carbamide peroxide (CP (Opalescence PF - Ultradent, South Jordan UT, USA. For G1 and G3, HP was applied on the enamel surface for 3 consecutive applications activated by HL. Each application included 3x3' HL activations with 1' between each interval; for G2 and G4, HP was applied 3x15' with 15' between intervals; and for G5, 15% CP was applied for 120'/10 days at home. A spectrophotometer was used to measure color change before the treatment and after 24 h, 1 week, 1, 6, 12, 18 and 24 months. A VAS questionnaire was used to evaluate tooth sensitivity before the treatment, immediately following treatment, 24 h after and finally 1 week after. RESULTS: Statistical analysis did not reveal any significant differences between in-office bleaching with or without HL activation related to effectiveness; nevertheless the time required was less with HL. Statistical differences were observed between the results after 24 h, 1 week and 1, 6, 12, 18 and 24 months (intergroup. Immediately, in-office bleaching increased tooth sensitivity. The groups activated with HL required less application time with gel. CONCLUSION: All techniques and bleaching agents used were effective and demonstrated similar behaviors.

  17. An Active Learning Exercise for Introducing Agent-Based Modeling

    Science.gov (United States)

    Pinder, Jonathan P.

    2013-01-01

    Recent developments in agent-based modeling as a method of systems analysis and optimization indicate that students in business analytics need an introduction to the terminology, concepts, and framework of agent-based modeling. This article presents an active learning exercise for MBA students in business analytics that demonstrates agent-based…

  18. Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial

    OpenAIRE

    LOGUERCIO, Alessandro Dourado; Lidia Yileng TAY; HERRERA,Daniel Rodrigo; Bauer,Jose; Reis, Alessandra

    2015-01-01

    The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE) was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0–4) during bleaching and up...

  19. Nonvital tooth bleaching: a review of the literature and clinical procedures.

    Science.gov (United States)

    Plotino, Gianluca; Buono, Laura; Grande, Nicola M; Pameijer, Cornelis H; Somma, Francesco

    2008-04-01

    Tooth discoloration varies in etiology, appearance, localization, severity, and adhesion to tooth structure. It can be defined as being extrinsic or intrinsic on the basis of localization and etiology. In this review of the literature, various causes of tooth discoloration, different bleaching materials, and their applications to endodontically treated teeth have been described. In the walking bleach technique the root filling should be completed first, and a cervical seal must be established. The bleaching agent should be changed every 3-7 days. The thermocatalytic technique involves placement of a bleaching agent in the pulp chamber followed by heat application. At the end of each visit the bleaching agent is left in the tooth so that it can function as a walking bleach until the next visit. External bleaching of endodontically treated teeth with an in-office technique requires a high concentration gel. It might be a supplement to the walking bleach technique, if the results are not satisfactory after 3-4 visits. These treatments require a bonded temporary filling or a bonded resin composite to seal the access cavity. There is a deficiency of evidence-based science in the literature that addresses the prognosis of bleached nonvital teeth. Therefore, it is important to always be aware of the possible complications and risks that are associated with the different bleaching techniques.

  20. Coordinating Learning Agents for Active Information Collection

    Science.gov (United States)

    2011-06-30

    ranging from robocup soccer [26, 27], to rover coordination [19], to trading agents [25, 43], to air traffic management [32]. What makes this problem...Bazzan, A. and Ossowski, S. (eds.), Applications of Agent Technology in Traffic and Transportation ( Springer , 2005). [19] Mataric, M. J., Coordination...of Complex Systems ( Springer , 2004). September 16, 2009 16:40 WSPC/169-ACS 00230 472 K. Tumer and N. Khani [24] Pynadath, D. and Tambe, M., The

  1. The effects of coral bleaching on settlement preferences and growth of juvenile butterflyfishes.

    Science.gov (United States)

    Cole, A J; Lawton, R J; Pisapia, C; Pratchett, M S

    2014-07-01

    Coral bleaching and associated mortality is an increasingly prominent threat to coral reef ecosystems. Although the effects of bleaching-induced coral mortality on reef fishes have been well demonstrated, corals can remain bleached for several weeks prior to recovery or death and little is known about how bleaching affects resident fishes during this time period. This study compared growth rates of two species of juvenile butterflyfishes (Chaetodon aureofasciatus and Chaetodon lunulatus) that were restricted to feeding upon either bleached or healthy coral tissue of Acropora spathulata or Pocillopora damicornis. Coral condition (bleached vs. unbleached) had no significant effects on changes in total length or weight over a 23-day period. Likewise, in a habitat choice experiment, juvenile butterflyfishes did not discriminate between healthy and bleached corals, but actively avoided using recently dead colonies. These results indicate that juvenile coral-feeding fishes are relatively robust to short term effects of bleaching events, provided that the corals do recover.

  2. Bleach Neutralizes Mold Allergens

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  3. BLEACHING NEPTUNE BALLS

    Directory of Open Access Journals (Sweden)

    BONET Maria Angeles

    2014-05-01

    Full Text Available Posidonia Oceanic is a seaweed from Mediterranean Sea and it is more concentrated at the Balerian SEA. This implies the Valencian Community also. It forms vaste underwater meadows in the sea and are part of the Mediterranean ecosystem. It is a sea-grass specie with fruits and flowers. Leaves are ribbon-like and they grow in winter and at the end of summer some of them are separated and arrive to some sea line. Fuit is separated and can floate, it is known as “the olive of the sea” mainly in Italy, or as the Neptune Balls. As it can be used in different fields, it is is being studied in order ro have the precitice tests. Some authors have reported the manufacturing of fully bio-based comites with a gluten matrix by hot-press molding. And it has been considered as an effective insulator for building industry or even though to determine the presence of mercure in the Mediterranean sea some years ago. As many applications can be designed from that fibers, it has been considered to be bleached in order to used them in fashionable products. Consequently, its original brown color is not the most suitable one and it should be bleached as many other cellulosic fibers. The aim of this paper is to bleache neptune balls however, the inner fibers were not accessible at all and it implied not to bleach the inner fibers in the neptune ball. Further studiesd will consider bleaching the individualized fibers.

  4. Enriching Active Databases with Agent Technology

    NARCIS (Netherlands)

    Akker, J.F.P. van den; Siebes, A.P.J.M.

    1997-01-01

    Intelligent agents are software components with a largely autonomous behaviour, that are fitted out with a considerable degree of artificial intelligence. They are a promising paradigm to serve as a foundation for future computing environments in general, and information systems in particular. At th

  5. Influence of post-bleaching time intervals on dentin bond strength.

    Science.gov (United States)

    Teixeira, Erica Cappelletto Nogueira; Turssi, Cecilia Pedroso; Hara, Anderson Takeo; Serra, Mônica Campos

    2004-01-01

    It has been reported that bond strength of resin to tooth structure can be reduced when the bonding procedure is carried out immediately after the bleaching treatment. This study evaluated the effect of bleaching of non-vital teeth bleaching on the shear bond strength (SBS) of composite resin/bovine dentin interface and the influence of delaying the bonding procedures for different time intervals following internal bleaching. According to a randomized block design, composite resin cylinders (Z100/Single bond - 3M) were bonded to the flattened dentin surface of two hundred and fifty-six teeth which had previously been subjected to four different treatments: SPH - sodium perborate + 30% hydrogen peroxide; SPW - sodium perborate + distilled water; CP - 37% carbamide peroxide; and CON - distilled water (control), each one followed by storage in artificial saliva for 0 (baseline), 7, 14, and 21 days after bleaching (n = 16). The bleaching agents in the pulp chambers were replaced every 7 days, over 4 weeks. The SBS test of the blocks was done using a universal testing machine. The ANOVA showed that there was no significant interaction between time and bleaching agents, and that the factor time was not statistically significant (p > 0.05). For the factor bleaching treatment, the Student's t-test showed that [CON = CP] > [SPW = SPH]. The bleaching of non-vital teeth affected the resin/dentin SBS values when sodium perborate mixed with 30% hydrogen peroxide or water was used, independently of the elapsed time following the bleaching treatment.

  6. Comparing the Effect of Different Bleaching Regims of Carbamide Peroxide on Microhardness of Z250 Composite

    Directory of Open Access Journals (Sweden)

    B Esmaeili

    2015-11-01

    Full Text Available Introduction: Bleaching products with oxidizing mechanism can exert side effects on the restorative materials existing in the oral cavity. Since bleaching agents are applied in different concentrations, the present study aimed to compare the effect of different bleaching regims of carbamide peroxide on microhardness of Z250 microhybride composite. Methods: In this in vitro study , 32 specimens of micro hybride composite (Z250 were made which were randomly divided into 4 subgroups (n=8: G1: bleached with10% carbamide peroxide 4 hours a day for 2 weeks G2: bleached with 16%carbamide peroxide 3 hours a day for 2 weeks G3: bleached with 22%carbamide peroxide 1hour a day for 2 weeks G4: the control subgroup stored in distilled water at 37◦c for 2 weeks. Microhardness of specimens was measured before and after bleaching using Vickers hardness testing machine. Moreover, the study data were analyzed statistically applying Anova and t-test (&alpha= 0.05. Results: This study findings revealed that using bleaching agent significantly decreased the  microhardness of composite resin in the bleaching groups compared to the control group, though the concentration of carbamide peroxide produced no significant effect on the microhardness value. (p>0.13 Conclusion: Bleaching therapy can cause a reduction in microhardness of Z250 composite and different concentrations of carbamide peroxide can reduce microhardness of Z250 to the same value.

  7. Effect of three nanobiomaterials on the surface roughness of bleached enamel

    OpenAIRE

    2015-01-01

    Background: The ever-increasing demand for enhanced esthetic appearance has resulted in significant developments in bleaching products. However, the enamel surface roughness (SR) might be negatively affected by bleaching agents. This in vitro study was undertaken to compare the effects of three nanobiomaterials on the enamel SR subsequent to bleaching. Materials and Methods: The crowns of six extracted intact nonerupted human third molars were sectioned. Five dental blocks measuring 2 mm × 3 ...

  8. Effects of green tea on the shear bond strength of orthodontic brackets after in-office vital bleaching.

    Science.gov (United States)

    Berger, Sandrine Bittencourt; Guiraldo, Ricardo Danil; Lopes, Murilo Baena; Oltramari-Navarro, Paula Vanessa; Fernandes, Thais Maria; Schwertner, Renata de Castro Alves; Ursi, Wagner José Silva

    2016-01-01

    The application of bleaching agents before placement of resin-bonded fixed appliances significantly, but temporarily, reduces bond strength to tooth structure. Antioxidants have been studied as a means to remove residual oxygen that compromises bonding to bleached enamel. This in vitro study evaluated whether green tea (GT) could restore the shear bond strength between bonded orthodontic brackets and bleached enamel. Six experimental groups were compared: group 1, no bleaching plus bracket bonding (positive control); group 2, bleaching with 35% hydrogen peroxide (HP) plus bracket bonding (negative control); group 3, 35% HP plus 10% sodium ascorbate (SA) plus bracket bonding; group 4, 35% HP plus 10% GT plus bracket bonding; group 5, no bleaching plus 10% SA plus bracket bonding; group 6, no bleaching plus 10% GT plus bracket bonding. Results suggested that GT, like SA, may be beneficial for bracket bonding immediately after bleaching.

  9. Chemical analysis of bleach and hydroxide-based solutions after decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX).

    Science.gov (United States)

    Hopkins, F B; Gravett, M R; Self, A J; Wang, M; Chua, Hoe-Chee; Hoe-Chee, C; Lee, H S Nancy; Sim, N Lee Hoi; Jones, J T A; Timperley, C M; Riches, J R

    2014-08-01

    Detailed chemical analysis of solutions used to decontaminate chemical warfare agents can be used to support verification and forensic attribution. Decontamination solutions are amongst the most difficult matrices for chemical analysis because of their corrosive and potentially emulsion-based nature. Consequently, there are relatively few publications that report their detailed chemical analysis. This paper describes the application of modern analytical techniques to the analysis of decontamination solutions following decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX). We confirm the formation of N,N-diisopropylformamide and N,N-diisopropylamine following decontamination of VX with hypochlorite-based solution, whereas they were not detected in extracts of hydroxide-based decontamination solutions by nuclear magnetic resonance (NMR) spectroscopy or gas chromatography-mass spectrometry. We report the electron ionisation and chemical ionisation mass spectroscopic details, retention indices, and NMR spectra of N,N-diisopropylformamide and N,N-diisopropylamine, as well as analytical methods suitable for their analysis and identification in solvent extracts and decontamination residues.

  10. Bleaching of Wool with Sodium Borohydride

    Directory of Open Access Journals (Sweden)

    Duygu Yilmazer, MSc.

    2009-09-01

    Full Text Available An untreated wool fabric was bleached both with sodium borohydride (SBH in the presence of sodium bisulphite (SBS solution and with a commercial H2O2 bleaching method. The concentration effects of SBH and SBS, bleaching time, pH and temperature on SBH bleaching process were investigated. Whiteness, yellowness and alkali solubility results were assessed for both bleaching methods. The results showed that whiteness degrees obtained with SBH bleaching was comparable with that of H2O2 bleaching method; whereas the alkali solubility values of the SBH bleaching was superior to the H2O2 bleaching.

  11. Effect of desensitizer application on shear bond strength of composite resin to bleached enamel

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2013-01-01

    Full Text Available Objective: Tooth sensitivity is common after vital tooth bleaching. The aim of this study is to evaluate the effect of a desensitizing agent on shear bond strength of composite resin to bleached enamel; and determine whether a delay of one or two weeks in bonding procedure is sufficient subsequent to bleaching/desensitizer regimen. Materials and Methods: Buccal enamel surfaces of ninety-six human sound molars were prepared and divided into eight groups. The surfaces of specimens in Group 1 as negative control group were bonded by composite resin using the single bond adhesive. Specimens in Groups 2-4 were bleached with an at-home bleaching agent (Daywhite ACP. Relief ACP desensitizing gel alone was applied in Group 5. In Groups 6-8, specimens were bleached same as in Group 2 and relief ACP desensitizing gel was applied same as inGroup 5 subsequent to each bleaching session. Composite cylinders were bonded after 24 h, 7 days and 14 days in Groups 2-4, respectively, and also in Groups 6-8, respectively. The shear bond strengths of the cylinders were tested and data was analyzed using two-way ANOVA and Tukey test (α = 0.05. Results: The results showed that bleaching and bleaching/desensitizer regimens significantly reduced the bond strength of composite resin to enamel. However, desensitizer alone did not reduce bond strength. No statistically significant differences were found between bleaching and bleaching/desensitizer regarding bond strength. Conclusion: Bleaching or bleaching/desensitizer treatment significantly decreases bond strength of composite resin to enamel. In both regimens, adhesive bonding is recommended after two weeks.

  12. The use of lactoperoxidase for the bleaching of fluid whey.

    Science.gov (United States)

    Campbell, R E; Kang, E J; Bastian, E; Drake, M A

    2012-06-01

    Lactoperoxidase (LP) is the second most abundant enzyme in bovine milk and has been used in conjunction with hydrogen peroxide (H₂O₂) and thiocyanate (SCN⁻) to work as an antimicrobial in raw milk where pasteurization is not feasible. Thiocyanate is naturally present and the lactoperoxidase system purportedly can be used to bleach dairy products, such as whey, with the addition of very little H₂O₂ to the system. This study had 3 objectives: 1) to quantify the amount of H₂O₂ necessary for bleaching of fluid whey using the LP system, 2) to monitor LP activity from raw milk through manufacture of liquid whey, and 3) to compare the flavor of whey protein concentrate 80% (WPC80) bleached by the LP system to that bleached by traditional H₂O₂ bleaching. Cheddar cheese whey with annatto (15 mL of annatto/454 kg of milk, annatto with 3% wt/vol norbixin content) was manufactured using a standard Cheddar cheesemaking procedure. Various levels of H₂O₂ (5-100 mg/kg) were added to fluid whey to determine the optimum concentration of H₂O₂ for LP activity, which was measured using an established colorimetric method. In subsequent experiments, fat-separated whey was bleached for 1h with 250 mg of H₂O₂/kg (traditional) or 20 mg of H₂O₂/kg (LP system). The WPC80 was manufactured from whey bleached with 250 mg of H₂O₂/kg or 20mg of H₂O₂/kg. All samples were subjected to color analysis (Hunter color values and norbixin extraction) and proximate analysis (fat, protein, and moisture). Sensory and instrumental volatile analyses were conducted on WPC80. Optimal LP bleaching in fluid whey occurred with the addition of 20mg of H₂O₂/kg. Bleaching of fluid whey at either 35 or 50°C for 1 h with LP resulted in > 99% norbixin destruction compared with 32 or 47% destruction from bleaching with 250 mg of H₂O₂/kg, at 35 or 50°C for 1 h, respectively. Higher aroma intensity and increased lipid oxidation compounds were documented in WPC80 from

  13. Three-month evaluation of vital tooth bleaching using light units-a randomized clinical study.

    Science.gov (United States)

    Polydorou, O; Wirsching, M; Wokewitz, M; Hahn, P

    2013-01-01

    The aim of this study was to evaluate the color stability of vital bleaching using a halogen unit, laser, or only chemical activation up to three months after treatment. A total of 60 patients were divided into three groups, and their teeth were bleached with 38% hydrogen peroxide using three methods: acceleration of the bleaching process with halogen (eight minutes), laser (30 seconds), or chemical activation only. All teeth were bleached a maximum of four times (4 × 15 minutes) until a change of six shade tabs took place. The color was evaluated both visually and with a spectrophotometer before bleaching, immediately after bleaching, and one and three months after bleaching. Directly after bleaching, the use of halogen showed better results than laser (p≤0.05). One and three months after bleaching, no significant difference was found between the tested methods relative to the shade change, independent of the method of shade evaluation (p>0.05). As far as the color stability is concerned, bleaching with halogen resulted in stable color throughout the three months (p>0.05), whereas the other two methods resulted in whiter teeth after one and three months compared with the color directly after bleaching (p≤0.05). Bleaching with laser needed more time than halogen for the desired shade change (p≤0.05). Although directly after treatment bleaching with halogen resulted in better results, one and three months after bleaching the kind of acceleration used in the bleaching process did not have any effect on the esthetic results.

  14. Bleaching of Black Human Hair

    Institute of Scientific and Technical Information of China (English)

    林琳

    2001-01-01

    Bleaching of black human hair has been studied systematically. On the basis of experimental data the technology of human hair bleaching through five processes was established. The optimum technology of improving the whiteness and reducing damage on fibers has been found. The technology can provide good luster,smooth handle and relatively high strength retention to human hair used for wigs or drama articles, meeting the needs of people better. Moreover, it also has important reference value to bleaching of other colored fibers.

  15. Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2012-01-01

    Conclusions: The findings suggest that bond strength of resin to bleached dentin may be affected with the adhesive system. Reduced SBS to bleached dentin can be amended by the use of SA as an antioxidizing agent. However, the amount of reversed bond strength subsequent to applying antioxidant might be related to the kind of dental adhesive.

  16. Activation of ATM by DNA Damaging Agents

    Science.gov (United States)

    2004-09-01

    activate ATM and/or ATM-dependent pathways 15 [61]. Indeed, phosphorylation of p53 on serines 20 and include quercetin [65], kaempferol , apigenin, and...protein [67] Phosphorylation on serine 15 [67] Kaempferol DSBf, SSBe Stimulation of kinase activity [67] Accumulation of p53 protein [67] Phosphorylation

  17. Ultrastructural evaluation of enamel after dental bleaching associated with fluoride.

    Science.gov (United States)

    Dominguez, John A; Bittencourt, Bruna; Michel, Milton; Sabino, Nilson; Gomes, João Carlos; Gomes, Osnara M M

    2012-08-01

    This study evaluated the effects on human enamel after two bleaching procedures: with a fluoridated bleaching agent and with topical fluoride application postbleaching. It used 43 enamel blocks (3 mm(2) ) that were ground flat (600-2,000 grit) and polished with polishing paste (one and one-fourth). Specimens were randomly divided into three groups according to the bleaching procedure: (1) control group, (2) hydrogen peroxide 35% (HPF) and topical application of fluoride 1.23%, and (3) HP 38% (OP) with fluoride in its composition. Bleaching agents were used according to the manufacturer's instructions. Three methodologies were used: nanoindentation, to observe surface hardness and elastic modulus; atomic force microscopy, to observe surface roughness (R(a) - R(z)); and scanning electron microscopy, to observe the enamel surface effects. Group OP had a decrease in the elastic modulus after bleaching, which was recovered at 14 days. An increased roughness (R(a); 32%) was observed on group HPF and had an increased erosion on enamel surface (67%). It was concluded that topical application of fluoride, after using the nonfluoridated whitening agent, increased the roughness values and erosion of enamel.

  18. Trace elementary concentration in enamel after dental bleaching using HI-ERDA

    Energy Technology Data Exchange (ETDEWEB)

    Added, N. [GFAA, Depto de Fisica Nuclear, IFUSP, University of Sao Paulo, Travessa R da rua do Matao 187, Cidade Universitaria, Caixa Postal 66318, CEP 05508-970 Sao Paulo, SP (Brazil)]. E-mail: nemitala@dfn.if.usp.br; Rizzutto, M.A. [GFAA, Depto de Fisica Nuclear, IFUSP, University of Sao Paulo, Travessa R da rua do Matao 187, Cidade Universitaria, Caixa Postal 66318, CEP 05508-970 Sao Paulo, SP (Brazil); Curado, J.F. [GFAA, Depto de Fisica Nuclear, IFUSP, University of Sao Paulo, Travessa R da rua do Matao 187, Cidade Universitaria, Caixa Postal 66318, CEP 05508-970 Sao Paulo, SP (Brazil); Francci, C. [School of Dentistry, University of Sao Paulo (Brazil); Markarian, R. [School of Dentistry, University of Sao Paulo (Brazil); Mori, M. [School of Dentistry, University of Sao Paulo (Brazil)

    2006-08-15

    Changes of elementary concentrations in dental enamel after a bleaching treatment with different products, is presented, with special focus on the oxygen contribution. Concentrations for Ca, P, O and C and some other trace elements were obtained for enamel of bovine incisor teeth by HI-ERDA measurements using a {sup 35}Cl incident beam and an ionization chamber. Five groups of teeth with five samples each were treated with a different bleaching agents. Each tooth had its crown sectioned in two halves, one for bleaching test and one the other used as a control. Average values of C/Ca, O/Ca, F/Ca enrichment factors were found. The comparison between bleached and non-bleached halves indicates that bleaching treatment did not affect the mineral structure when low-concentration whitening systems were used. The almost constant oxygen concentration in enamel, suggests little changes due to whitening therapy.

  19. RESPONSE SURFACE METHODOLOGY APPROACH FOR OPTIMIZATION OF FLAX SEED OIL BLEACHING PROCESS

    Directory of Open Access Journals (Sweden)

    Miroslav Ondrejovič

    2013-10-01

    Full Text Available Flax seed is an important source of omega-3 polyunsaturated fatty acids essential for human physiology. For low oxidation stability, specific taste and concomitant color compounds this oil is poorly applicable as nutraceutical additive. The aim of this study was optimization of flax seed oil bleaching. The optimal conditions for the bleaching process were determined using response surface methodology. A central composite design was used to investigate the effects of three independent variables, namely solid to liquid ratio, temperature and time, to output parameters of the bleaching process such as crude oil color expressed as optical density at 490 nm, acid and peroxide value. Calculated optimal conditions for the bleaching, expressed by the optical density of the oil were as follows: temperature 50°C, bleaching time 77 minutes and solid-liquid ratio 56 g of bleaching agent to 1 liter of oil.

  20. Space as an invention of active agents

    Directory of Open Access Journals (Sweden)

    Alexander V Terekhov

    2016-03-01

    Full Text Available The question of the nature of space around us has occupied thinkers since the dawn of humanity, with scientists and philosophers today implicitly assuming that space is something that exists objectively. Here we show that this does not have to be the case: the notion of space could emerge when biological organisms seek an economic representation of their sensorimotor flow. The emergence of spatial notions does not necessitate the existence of real physical space, but only requires the presence of sensorimotor invariants called 'compensable' sensory changes. We show mathematically and then in simulations that naive agents making no assumptions about the existence of space are able to learn these invariants and to build the abstract notion that physicists call rigid displacement, independent of what is being displaced. Rigid displacements may underly perception of space as an unchanging medium within which objects are described by their relative positions. Our findings suggest that the question of the nature of space, currently exclusive to philosophy and physics, should also be addressed from the standpoint of neuroscience and artificial intelligence.

  1. Garcinia xanthones as orally active antitumor agents.

    Science.gov (United States)

    Zhang, Xiaojin; Li, Xiang; Sun, Haopeng; Wang, Xiaojian; Zhao, Li; Gao, Yuan; Liu, Xiaorong; Zhang, Shenglie; Wang, Yanyan; Yang, Yingrui; Zeng, Su; Guo, Qinglong; You, Qidong

    2013-01-10

    Using a newly developed strategy whose key step is the regioselective propargylation of hydroxyxanthone substrates, 99 structurally diverse Garcinia natural-product-like xanthones based on gambogic acid were designed and synthesized and their in vitro antitumor activity was evaluated. A set of 40 related compounds was chosen for determination of their physicochemical properties including polar surface area, log D₇.₄, aqueous solubility, and permeability at pH 7.4. In the light of the in vitro antitumor activity and the physicochemical properties, two compounds were advanced into in vivo efficacy experiments. The antitumor activity of compound 112, administered po, showed more potent in vivo oral antitumor activity than gambogic acid.

  2. Thermographic and spectrophotometric analysis of the extrinsic tooth bleaching using a diode laser and a LED system. In vitro; Analise termografica e espectrofotometrica do clareamento dental extrinsico utilizando laser de diodo e sistema de LED. Estudio In vitro

    Energy Technology Data Exchange (ETDEWEB)

    Micheli, Paola Racy de

    2004-07-01

    The aim of this study was to evaluate the intra-pulpal temperature change, as well as to compare the bleaching power of a 38% hydrogen peroxide (Opalescence Xtra Boost- Ultradent. Inc), when activated with a diode laser, with a LED system and without activation, in the extrinsic tooth bleaching in vitro. Ten mandibular human incisors, a thermocouple, 45 bovine incisors and a spectrophotometer (Shade Eye- Shofu) for the color analysis. The samples were divided into 3 groups: 38% hydrogen peroxide activated by a diode laser (ZAP lasers, wavelength 808 nm {+-} 5, power of 1,4 W); 38% hydrogen peroxide activated by LED (Bright LEC-Mmoptics, wavelength 470 nm {+-} 25, power of 380 mW); 38% hydrogen peroxide without activation. After the artificial pigmentation, the bleaching agent acted for the same time in the 3 groups, differing only by the type of activation. The results of temperature showed that the LED activation was safer than the diode laser, which, in some measures exceeded the limit of 5.6 deg C. The luminosity of the samples did not show significantly statistics differences in none of the groups and moments of this study. The diode laser and LED activation did not influenced at the bleaching power of the peroxide, which showed effective for removing stains, with great capacity of bleaching bovine tooth artificially darkened. (author)

  3. Enamel susceptibility to red wine staining after 35% hydrogen peroxide bleaching

    Directory of Open Access Journals (Sweden)

    Sandrine Bittencourt Berger

    2008-06-01

    Full Text Available Concern has been expressed regarding the staining of enamel surface by different beverages after bleaching. This study investigated the influence of 35% hydrogen peroxide bleaching agents on enamel surface stained with wine after whitening treatments. Flat and polished bovine enamel surfaces were submitted to two commercially available 35% hydrogen peroxide bleaching agents or kept in 100% humidity, as a control group (n = 10. Specimens of all groups were immersed in red wine for 48 h at 37°C, immediately, 24 h or 1 week after treatments. All specimens were ground into powder and prepared for the spectrophotometric analysis. Data were subjected to two-way analysis of variance and Fisher's PLSD test at 5% significance level. The amount of wine pigments uptake by enamel submitted to bleaching treatments was statistically higher than that of control group, independently of the evaluation time. Results suggested that wine staining susceptibility was increased by bleaching treatments.

  4. AFM analysis of bleaching effects on dental enamel microtopography

    Science.gov (United States)

    Pedreira de Freitas, Ana Carolina; Espejo, Luciana Cardoso; Botta, Sergio Brossi; Teixeira, Fernanda de Sa; Luz, Maria Aparecida A. Cerqueira; Garone-Netto, Narciso; Matos, Adriana Bona; Salvadori, Maria Cecilia Barbosa da Silveira

    2010-02-01

    The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 μm × 15 μm area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

  5. AFM analysis of bleaching effects on dental enamel microtopography

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira de Freitas, Ana Carolina, E-mail: anacarolfreitas@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Cardoso Espejo, Luciana, E-mail: luespejo@hotmail.com [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Brossi Botta, Sergio, E-mail: sbbotta@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Sa Teixeira, Fernanda de, E-mail: nandast@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil); Cerqueira, Luz Maria Aparecida A., E-mail: maacluz@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Garone-Netto, Narciso, E-mail: ngarone@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Bona Matos, Adriana, E-mail: bona@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Barbosa da Silveira Salvadori, Maria Cecilia, E-mail: mcsalva@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil)

    2010-02-15

    The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 {mu}m x 15 {mu}m area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

  6. Removing benzopyrene from oil -tea camellia seed oil by different decoloring agents in bleaching process%脱色工艺中不同脱色剂对油茶籽油中苯并芘脱除效果的影响

    Institute of Scientific and Technical Information of China (English)

    罗凡; 费学谦; 方学智; 陈焱; 王亚萍

    2012-01-01

    研究了在优化的脱色条件下,脱色剂对油茶籽油中苯并芘的脱除作用.结果表明:活性炭对油茶籽油中苯并芘脱除效果显著,加入油质量3%的活性炭可以完全脱除样品中的苯并芘(苯并芘含量为7.12μg/kg);活性白土基本不具备脱除苯并芘的能力,但在活性炭中加入活性白土后,活性白土优先脱除油茶籽油中色素等杂质,为活性炭对苯并芘的脱除保留了吸附能力,使得活性炭对苯并芘的脱除效率提高,在3%活性白土的存在下,加入油质量0.3%的活性炭即可达到单独使用3%活性炭对苯并芘的脱除量,相当于将脱除苯并芘的能力提高10倍左右.%The removal of benzopyrene in oil -tea camellia seed oil by different decoloring agents during bleaching process was investigated. The results demonstrated that the effect of active carbon on the removal of benzopyrene in oil -tea camellia seed oil was significant. The benzopyrene (7.12 μg/kg) in the sample oil could be removed thoroughly with active carbon dosage of 3% (based on the mass of the oil). The active clay did not have the ability of removing benzopyrene, but when mixing with active carbon , the active clay could increase the adsorptive capacity of active carbon, because the active clay was prior to remove the impurities in oil - tea camellia seed oil such as pigment. In the presence of 3% active clay in the oil, the active carbon could remove benzopyrene completely with active carbon dosage of 0. 3% (based on the mass of the oil),and the removal efficiency of active carbon could improve nearly 10 times.

  7. Inflammatory response of human dental pulp to at-home and in-office tooth bleaching

    Directory of Open Access Journals (Sweden)

    Maysa Magalhães Vaz

    Full Text Available ABSTRACT Tooth bleaching is a technique of choice to obtain a harmonious smile, but bleaching agents may damage the dental pulp. Objective: This study evaluated the inflammatory responses of human dental pulp after the use of two bleaching techniques. Material and Methods: Pulp samples were collected from human third molars extracted for orthodontic reasons and divided into three groups: control - no tooth bleaching (CG (n=7; at-home bleaching with 15% carbamide peroxide (AH (n = 10, and in-office bleaching with 38% hydrogen peroxide (IO (n=12. Pulps were removed and stained with hematoxylin-eosin for microscopic analysis of inflammation intensity, collagen degradation, and pulp tissue organization. Immunohistochemistry was used to detect mast cells (tryptase+, blood vessels (CD31+, and macrophages (CD68+. Chi-square, Kruskal-Wallis, and Mann Whitney tests were used for statistical analysis. The level of significance was set at p0.05. No mast cells were found in the pulp samples analyzed. Conclusion: In-office bleaching with 38% hydrogen peroxide resulted in more intense inflammation, higher macrophages migration, and greater pulp damage then at-home bleaching with 15% carbamide peroxide, however, these bleaching techniques did not induce migration of mast cells and increased the number of blood vessels.

  8. Análise da rugosidade superficial de materiais restauradores estéticos: efeito de agentes clareadores e tempo = Analysis of roughness surface of aesthetic restoring materials: effect of bleaching agentes and time

    Directory of Open Access Journals (Sweden)

    Pozzobon, Roselaine Terezinha

    2005-01-01

    Full Text Available Este estudo in vitro avaliou o efeito de agentes clareadores na rugosidade superficial (Ra de materiais restauradores estéticos, com o passar do tempo. Foram utilizadas duas resinas compostas, Z100 (M1 e Silux-Plus (M2, um compômero, Dyract (M3 e um ionômero de vidro modificado por resina, Vitremer (M4, que foram expostos a dois agentes clareadores: Opalescence (C1, peróxido de carbamida 10%, e Hi-Lite (C2, peróxido de hidrogênio 35% e como meio de imersão foi utilizada saliva artificial (Co. Foram confeccionados 120 corpos de prova, sendo a Ra avaliada após 1 hora de confecção; e antes da imersão em saliva artificial (T0, após 1dia (T1, 7 (T2, 15 (T3 e 30 (T4 dias de exposição aos agentes clareadores. No grupo controle, os corpos-de-prova ficaram somente imersos em saliva artificial. Após análise estatística de variância ANOVA (a = 5%, teste de Tukey, e método da decomposição da soma de quadrados, foi possível concluir que: 1 – a Ra dos materiais restauradores estéticos, de forma geral, alterou-se após exposição aos diferentes agentes clareadores e ao longo do tempo; 2 – em função do material restaurador, M2 apresentou a maior média de Ra, seguido em ordem decrescente por M4, M3 e M1; 3 – C1 e C2 exerceram ação sobre a superfície dos materiais restauradores aumentando a Ra para todos os materiais avaliados, principalmente em M2 e M4; 4 – em função do fator tempo, observou-se influência estatisticamente significativa sobre a Ra, pois quanto maior o tempo de exposição ao agente clareador, maiores os valores médios de Ra

  9. An Activity Systems Theory Approach to Agent Technology

    OpenAIRE

    Zhang, Peng; Bai, Guohua

    2005-01-01

    In the last decade, Activity Theory has been discussed a lot in Human-Computer Interaction (HCI) and Computer Supported Cooperative Work (CSCW). Activity Theory was used both theoretically as an analytical method and practically as a development framework for Information Systems. Meanwhile, there is a new trench from Artificial Intelligence. Artificial Intelligence researchers find that the fruit from Activity Theory study may contribute, especially to Agent Technology, with socio-psychologic...

  10. The effect of enamel bleaching on the shear bond strengths of metal and ceramic brackets.

    Science.gov (United States)

    Oztaş, E; Bağdelen, G; Kiliçoğlu, H; Ulukapi, H; Aydin, I

    2012-04-01

    The aim of this study was to evaluate the effects of bleaching and delayed bonding on the shear bond strengths of metal and ceramic brackets bonded with light and chemically cure composite resin to human enamel. One hundred and twenty extracted human premolar teeth were randomly divided into three groups of 40 each. The first two groups were bleached with 20 per cent carbamide peroxide (CP) at-home bleaching agent. No bleaching procedures were applied to the third group and served as control. The first two and control groups were divided into equal subgroups according to different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after bleaching process was completed while the specimens in group 2 (n = 40) were bonded 14 days after. The specimens in all groups were debonded with a Universal testing machine while the modified adhesive remnant index was used to evaluate fracture properties. No statistically significant differences were found between the shear bond strengths of metal and ceramic brackets bonded to bleached enamel after 24 hours, 14 days, and unbleached enamel with light or chemical cure adhesives (P > 0.05). The mode of failure was mostly at the bracket/adhesive interface and cohesive failures within the resin were also observed. Our findings indicated that at-home bleaching agents that contain 20 per cent CP did not significantly affect the shear bond strength of metal and ceramic orthodontic brackets to enamel when bonding is performed 24 hours or 14 days after bleaching.

  11. Evaluation of temperature increase during in-office bleaching

    Science.gov (United States)

    MONDELLI, Rafael Francisco Lia; SOARES, Ana Flávia; PANGRAZIO, Eugenio Gabriel Kegler; WANG, Linda; ISHIKIRIAMA, Sergio Kiyoshi; BOMBONATTI, Juliana Fraga Soares

    2016-01-01

    ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser), a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05). Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C). The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C). The addition of a bleaching gel led to a higher increase in intrapulpal temperatures. PMID:27119761

  12. Evaluation of temperature increase during in-office bleaching

    Directory of Open Access Journals (Sweden)

    Rafael Francisco Lia MONDELLI

    2016-04-01

    Full Text Available ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser, a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05. Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C. The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C. The addition of a bleaching gel led to a higher increase in intrapulpal temperatures.

  13. CO2 capture performance of bi-functional activated bleaching earth modified with basic-alcoholic solution and functionalization with monoethanolamine: isotherms, kinetics and thermodynamics.

    Science.gov (United States)

    Pongstabodee, Sangobtip; Pornaroontham, Phuwadej; Pintuyothin, Nuthapol; Pootrakulchote, Nuttapol; Thouchprasitchai, Nutthavich

    2016-10-01

    CO2 capture performance of bifunctional activated bleaching earth (ABE) was investigated at atmospheric pressure. The sorbents were characterized by means of X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Caron-Hydrogen-Nitrogen analysis (CHN), Fourier transform infrared (FT-IR) and thermal gravimetric analysis (TGA). The CO2 capacity was enhanced via basic-modification and monoethanolamine (MEA) loading of the ABE sorbent to obtain a bifunctional surface property. Here, basic-modified calcined ABE with a 30wt.% MEA loading (SAB-30) showed the highest CO2 capture capacity, but this was decreased with excess MEA loading (>30wt.%). At a 10% (V/V) initial CO2 concentration feed, the maximum capacity of SAB-30 increased from 2.71mmol/g at 30°C (without adding moisture to the feed) to 3.3mmol/g at 50°C when adding 10% (V/V) moisture to the feed. Increasing the moisture concentration further reduced the maximum CO2 capacity due to the blocking effect of the excess moisture on the sorbent surface. However, SAB-30 could completely capture CO2 even in a 100% (V/V) initial CO2 concentration feed. A maximum CO2 capacity of 5.7mmol/g for SAB-30 was achieved at 30°C. Varying the ratio of sorbent weight to total flow rate of the gas stream had no discernible effect on the equilibrium CO2 capture capacity. Avrami's equation and Toth's isotherm model provided a good fitting for the data and suggested the presence of more than one reaction pathway in the CO2 capture process and the heterogeneous adsorption surface of SAB-30. Thermodynamics studies revealed that CO2 capture on the bifunctional SAB-30 is feasible, spontaneous and exothermic in nature.

  14. Efficacy of a novel at-home bleaching technique with carbamide peroxides modified by CPP-ACP and its effect on the microhardness of bleached enamel.

    Science.gov (United States)

    Borges, B C D; Borges, J S; de Melo, C D; Pinheiro, I V A; Santos, A J S Dos; Braz, R; Montes, M A J R

    2011-01-01

    This study was designed to evaluate in vitro the efficacy of a novel at-home bleaching technique using 10% or 16% carbamide peroxide modified by casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and its influence on the microhardness of bleached enamel. A total of 40 bovine incisors were divided into four groups (n=10) according to the bleaching agent used: 10% carbamide peroxide only; a blend of 10% carbamide peroxide and a CPP-ACP paste; 16% carbamide peroxide only; and a blend of 16% carbamide peroxide and a CPP-ACP paste. During the 14-day bleaching regimen, the samples were stored in artificial saliva. The Vickers microhardness and color of the teeth were assessed at baseline (T0) and immediately after the bleaching regimen (T14) using a microhardness tester and a spectrophotometer, respectively. The degree of color change was determined by the Commission Internationale de l'Eclariage (CIE) L*a*b* system (ΔE, ΔL*, Δa*, and Δb*) and Vita shade guide parameters. The data were analyzed by analysis of variance and the Tukey test (pmicrohardness values at T14 compared with T0, whereas the samples that were bleached with peroxide only did not show any differences in their microhardness values. All of the bleaching agents were effective at whitening the teeth and did not show a statistically significant difference using the CIEL*a*b* system (ΔE, ΔL*, Δa*, and Δb*) or the Vita shade guide parameters. The use of a CPP-ACP paste with carbamide peroxide bleaching agents increased the bleached enamel's microhardness and did not have an influence on whitening efficacy.

  15. Chalcone derivatives as potential antifungal agents: Synthesis, and antifungal activity

    Directory of Open Access Journals (Sweden)

    Deepa Gupta

    2015-01-01

    Full Text Available Much research has been carried out with the aim to discover the therapeutic values of chalcone derivatives. Chalcones possess wide range of pharmacological activity such as antibacterial, antimalarial, antiprotozoal, antitubercular, anticancer, and antifungal agents etc. The presence of reactive α,β-unsaturated keto group in chalcones is found to be responsible for their biological activity. The rapid developments of resistance to antifungal agents, led to design, and synthesize the new antifungal agents. The derivatives of chalcones were prepared using Claisen-Schmidt condensation scheme with appropriate tetralone and aldehyde derivatives. Ten derivatives were synthesized and were biologically screened for antifungal activity. The newly synthesized derivatives of chalcone showed antifungal activity against fungal species, Microsporum gypseum. The results so obtained were superior or comparable to ketoconazole. It was observed that none of the compounds tested showed positive results for fungi Candida albicans nor against fungi Aspergillus niger. Chalcone derivatives showed inhibitory effect against M. gypseum species of fungus. It was found that among the chalcone derivatives so synthesized, two of them, that is, 4-chloro derivative, and unsubstituted derivative of chalcone showed antifungal activity superior to ketoconazole. Thus, these can be the potential new molecule as antifungal agent.

  16. Keratin sponge/hydrogel II, active agent delivery

    Science.gov (United States)

    Keratin sponge/hydrogels from oxidation and reduction hydrolysis of fine and coarse wool fibers were formed to behave as cationic hydrogels to swell and release active agents in the specific region of the gastro-intestinal (GI) tract. Their porous, interpenetrating networks (IPN) were effective for...

  17. Exogenous bleaching evaluation on dentin using chemical activated technique compared with diode laser technique; Avaliacao do clareamento exogeno sobre a dentina realizado pela tecnica por ativacao quimica comparada com a tecnica por ativacao pelo laser de diodo

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Breno Carnevalli Franco de

    2003-07-01

    This in vitro study compared the results of different exogenous bleaching proceedings on dentin after treatment of enamel surface. Thirty human canine were hewn preserving the vestibular half of the crown and 3 mm of root, showing a vestibular-lingual thickness average of 3,5 mm, measuring in the third middle of the crown. Ali teeth were maintained in wet chamber during the experiment. Digital photographs were taken of the dentin surface at 3 experimental times (LI: initial record, L0: immediate pos-bleaching record and L 15: 15 days after bleaching). The teeth were divided into 3 experimental groups of 10 teeth in each. The Control Group did not receive any kind of treatment. The Laser Group received 2 session of laser bleaching, with 3 applications each, using 35% hydrogen peroxide, activated by diode laser during 30 seconds, by scanning the enamel surface from incisal edge to the top of the crown, from mesial to distal portion of the crown and circularly, each movement during 10 seconds. The following parameters being adopted: wavelength of 808 nm, power of 1,5 W and optic fiber with 600 {mu}m (core). The Peroxide Group received 28 daily applications, during 4 hours each application, using 16% carbamide peroxide. The bleaching records were analysed using a computer, through RGBK (red, green , blue and black). The K averages (K=100% for black and K=0% for white) of the records for Control Group were: LI=50,1 %, L0=50,3% and L 15=50,6%. For Laser Group the K averages were LI=48,5%, L0=50,0% and L 15=47,7%. And for the Peroxide Group were LI=50,5%, L0=35,9% and L 15=37,3%. The statistical analysis showed no significant difference of the K between the Control Group and the Laser Group, as to LI, L0 and L 15. Only Peroxide Group showed significant statistical difference between LI with L0 and L 15 (0,1%), and L0 in comparison with L 15 did not show any difference. (author)

  18. Effect of carbamide peroxide-based bleaching agents containing fluoride or calcium on tensile strength of human enamel Efeito de agentes clareadores à base de peróxido de carbamida contendo fluoreto e cálcio na resistência à tração do esmalte humano

    Directory of Open Access Journals (Sweden)

    Marcelo Giannini

    2006-04-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effects of carbamide peroxide-based bleaching agents (CPG containing fluoride (CF or calcium (CCa on the ultimate tensile strength of enamel (UTS. METHOD: A "cube-like" resin composite structure was built-up on the occlusal surface of twenty-two sound third molars to facilitate specimen preparation for the micro-tensile test. The restored teeth were serially sectioned in buccal-lingual direction in slices with approximate 0.7 mm thickness. Each slice was trimmed with a fine diamond bur to reduce the buccal, internal slope enamel of the cusps to a dumb-bell shape with a cross-sectional area at the "neck" of less than 0.5 mm². The samples were randomly divided into 12 groups (n=11. The control groups were not submitted to the bleaching regimen. Specimens were treated with 10% CPG gel or with 10% CPG formulations containing CF (0.2% and 0.5% or CCa (0.05% and 0.2%. Bleached groups received the application of the 10% CPGs for 6 hours/day at 37º C, during 14 consecutive days and were stored in artificial saliva (AS or 100% relative humidity (RH among each application. After bleaching, specimens were tested with the microtensile method at 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test (5%. RESULTS: No significant difference was observed between groups stored in AS or RH. Specimens treated with CF or CCa presented similar UTS as unbleached control groups. CONCLUSION: Either 10% CPG formulations containing CF or CCa can preserve the UTS after bleaching regimen.OBJETIVO: O propósito deste estudo foi avaliar os efeitos de agents clareadores à base de peróxido de carbamida (CPG contendo fluoreto (CF e cálcio (CCa na resistência à tração do esmalte (UTS. MÉTODO: Um bloco de resina composta foi confeccionada na superfície oclusal de vinte e dois terceiros molars hígidos para facilitar a preparação dos espécimes para o teste de micro-tração. Os dentes restaurados foram

  19. Effect of bleaching whey on sensory and functional properties of 80% whey protein concentrate.

    Science.gov (United States)

    Jervis, S; Campbell, R; Wojciechowski, K L; Foegeding, E A; Drake, M A; Barbano, D M

    2012-06-01

    Whey is a highly functional food that has found widespread use in a variety of food and beverage applications. A large amount of the whey proteins produced in the United States is derived from annatto-colored Cheddar cheese. Color from annatto is undesirable in whey and must be bleached. The objective of this study was to compare 2 commercially approved bleaching agents, benzoyl peroxide (BP) and hydrogen peroxide (HP), and their effects on the flavor and functionality of 80% whey protein concentrate (WPC80). Colored and uncolored liquid wheys were bleached with BP or HP, and then ultrafiltered, diafiltered, and spray-dried; WPC80 from unbleached colored and uncolored Cheddar whey were manufactured as controls. All treatments were manufactured in triplicate. The WPC80 were then assessed by sensory, instrumental, functionality, color, and proximate analysis techniques. The HP-bleached WPC80 were higher in lipid oxidation compounds (specifically hexanal, heptanal, octanal, nonanal, decanal, dimethyl disulfide, and 1-octen-3-one) and had higher fatty and cardboard flavors compared with the other unbleached and BP-bleached WPC80. The WPC80 bleached with BP had lower norbixin concentrations compared with WPC80 bleached with HP. The WPC powders differed in Hunter color values (L, a, b), with bleached powders being more white, less red, and less yellow than unbleached powders. Bleaching with BP under the conditions used in this study resulted in larger reductions in yellowness of the powders made from whey with annatto color than did bleaching with HP. Functionality testing demonstrated that whey bleached with HP treatments had more soluble protein after 10 min of heating at 90°C at pH 4.6 and pH 7 than the no-bleach and BP treatments, regardless of additional color. Overall, HP bleaching caused more lipid oxidation products and subsequent off-flavors compared with BP bleaching. However, heat stability of WPC80 was enhanced by HP bleaching compared with control or BP-bleached

  20. Antifungal activity of propolis against Fonsecaea pedrosoi, a chromoblastomycosis agent

    OpenAIRE

    2011-01-01

    Chromoblastomycosis is a subcutaneous mycosis caused by dematiaceous fungi, being Fonsecaea pedrosoi the main etiologic agent in Brazil. Propolis is a resinous material collected by honeybees, with variable composition and pharmacological properties, including antifungal activity. The antifungal activity of ethanolic extracts of propolis (EEP) obtained from different municipalities of the state of Rio Grande do Sul, Brazil, against F. pedrosoi strains was assessed. The EEP showed MIC values b...

  1. Detecting malicious activities with user-agent-based profiles

    OpenAIRE

    2015-01-01

    Hypertext transfer protocol (HTTP) has become the main protocol to carry out malicious activities. Attackers typically use HTTP for communication with command-and-control servers, click fraud, phishing and other malicious activities, as they can easily hide among the large amount of benign HTTP traffic. The user-agent (UA) field in the HTTP header carries information on the application, operating system (OS), device, and so on, and adversaries fake UA strings as a way to evade detection. Moti...

  2. MgO nanoparticles as antibacterial agent: preparation and activity

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhen-Xing, E-mail: tangzhenxing@126.com [Department of Food Science, Anqing, Vocational and Technical College, Anqing, Anhui (China); Lv, Bin-Feng [Date Palm Research Center, King Faisal University, (Saudi Arabia)

    2014-07-15

    Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are reviewed. (author)

  3. MgO nanoparticles as antibacterial agent: preparation and activity

    OpenAIRE

    Zhen-Xing Tang; Bin-Feng Lv

    2014-01-01

    Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are r...

  4. Effect of casein phosphopeptide-amorphous calcium phosphate on the flexural strength of enamel-dentin complex following extracoronal bleaching

    Directory of Open Access Journals (Sweden)

    Diatri Nari Ratih

    2015-03-01

    Full Text Available Background: Bleaching can affect the mechanical properties of enamel-dentin complex, such as flexural strength. Casein phosphopeptide-amorphus calcium phosphate (CPP-ACP is often used following bleaching treatment to reduce hypersensitivity and to increase demineralization of tooth. Purpose: The purpose of the study was to investigate the effect of CPP-ACP on the flexural strength of enamel-dentin complex following extracoronal bleaching. Methods: Forty-eight enamel-dentin plates (size 8 x 2 x 3 mm were randomly assigned into 6 groups, each consisted of 8 samples. Group 1, no bleaching and immersed in artificial saliva. Group 2, no bleaching, CPP-ACP application only. Group 3, bleaching using 15% carbamide peroxide. Group 4, similar to group 3, except application of CPP-ACP for the times between bleaching. Group 5, bleaching with 40% hydrogen peroxide. Group 6, similar to group 5, except application of CPP-ACP for the times between bleaching. Flexural strength of each enamel-dentin plate was tested by threepoint bending test using universal testing machine. Results: The results showed that 15% carbamide peroxide and 40% hydrogen peroxide significantly reduced flexural strength of enamel-dentin (216.25±26.44 MPa and 206.67±32.07 MPa respectively. Conversely, application of CPP-ACP following both bleachings increased flexural strength (266.75± 28.27MPa and 254.58±36.59 MPa respectively. A two-way Anova revealed that extracoronal bleaching agents significantly reduced flexural strength (p<0.05. Conclusion: Extracoronal bleaching agents reduce flexural strength, whereas application of CPP-ACP following bleaching either with 15% carbamide peroxide or 40% hydrogen peroxide can increase the flexural strength of enamel-dentin complex.

  5. Evaluation of shear bond strength of orthodontic brackets bonded on the tooth surface after internal bleaching

    Directory of Open Access Journals (Sweden)

    Nadia de Souza FERREIRA

    Full Text Available Introduction: There is great demand for esthetic treatment by patients who have discolored teeth, because currently aesthetic standards have become stricter and many patients have tooth bleaching procedures performed before or during orthodontic treatment. Objective: To evaluate the bonding of orthodontic brackets to human molars after internal tooth bleaching. Material and method: Forty molars were divided into four groups according to the bleaching agent used: PS sodium perborate + water; PC carbamide peroxide; PC + PS carbamide peroxide + sodium perborate; Cont water (control group. Bleaching agents placed inside the pulp chambers were replaced every 7 days for 2 weeks, and the brackets were bonded 30 days after the end of bleaching. The shear strength test was performed in a universal testing machine (Emic. Result: ANOVA with a significance level of 5% (p > 0.05, showed no statistically significant difference between groups (p = 0.1214. Conclusion: It was concluded that the different bleaching agents studied did not interfere with the bond strength of brackets to enamel and bonding the brackets 30 days after internal bleaching is a safe procedure.

  6. Effect of pH values of two bleaching gels on enamel microhardness.

    Science.gov (United States)

    Araujo, Natalia Costa; da Costa Soares, Manuella Uilmann Silva; Nery, Marcela Maria; Sales, Wagno Silva; Gerbi, Marleny Elizabeth Martinez

    2013-07-01

    This study evaluated the influence of bleaching gel pH and the effect of remineralizing gels after bleaching in different time intervals. Sixty bovine incisors were divided into 2 groups (n = 30). Group 1 was bleached with a 35% hydrogen peroxide (HP) acid gel and Group 2 was bleached with a 35% HP neutral gel. Each group was then divided into 3 subgroups (n = 10) according to the post-bleaching treatment used: storage in artificial saliva, application of a fluoride gel, or application of a gel consisting of fluoride, potassium nitrate, and nanostructured calcium phosphate. Specimens were stored in artificial saliva, and enamel microhardness was evaluated at 24 hours and 15 days postbleaching. Vickers microhardness data were analyzed by means of 2-way ANOVA, with repeated measurements and Bonferroni's post-hoc test. Twenty-four hours after bleaching, no significant differences were found between the bleaching gels. At 15 days postbleaching, Group 2 samples demonstrated a significant reduction in microhardness. No significant differences were found between the remineralizing gels, though all of the postbleaching treatments after the use of 35% neutral gel were able to re-establish baseline microhardness. It was concluded that neutral bleaching gel significantly reduced enamel microhardness 15 days after bleaching and that the use of remineralizing gels did not significantly enhance the microhardness of bleached enamel. However, in clinical situations, the acquired enamel pellicle protects tooth surfaces, and postbleaching, decalcified enamel would undergo recalcification. This study indicates that it is important to consider the bleaching agent's pH and composition when treating patients with reduced salivary secretion.

  7. Effect of two different tooth bleaching techniques on microhardness of giomer

    Science.gov (United States)

    Bahari, Mahmoud; Naser-Alavi, Fereshteh; Behboodi, Soodabeh

    2017-01-01

    Background Tooth bleaching is a safe and conservative treatment modality to improve the esthetic appearance of discolored teeth. One of the problems with the use of bleaching agents is their possible effect on surface microhardness of resin-based materials. The present study was carried out to evaluate the effect of in-office and at-home bleaching on surface microhardness of giomer. Material and Methods Seventy-five disk-shaped giomer samples (Beautifil II) were prepared and cured with a light-curing unit. The samples were randomly assigned to three groups (n=25). In group 1 (control), the samples were stored in distilled water for 14 days. The samples in groups 2 and 3 underwent a bleaching procedure with 15% carbamide peroxide (CP) (8 hours daily) and 45% CP (30 minutes daily), respectively, for 14 days. Finally, the microhardness of samples was measured with Vickers hardness tester using a 100-g force for 20 seconds. One-way ANOVA was used to compare the mean microhardness values among the study groups, followed by post hoc Tukey test for two-by-two comparison of the groups. Statistical significance was set at P<0.05. Results One-way ANOVA showed significant differences in the mean microhardness values among the study groups (P<0.001). Based on the results of Tukey test, microhardness in the bleached groups was significantly less than that in the control group (P<0.0005). In addition, microhardness in the 45% CP group was significantly less than that in the 15% CP group (P<0.0005). Conclusions Use of both bleaching agents during in-office and at-home bleaching techniques resulted in a decrease in surface microhardness of giomer. The unfavorable effect of in-office bleaching (45% CP) was greater than that of at-home bleaching (15% CP). Key words:Dental restorations, hardness, tooth bleaching. PMID:28210444

  8. In Situ and In Vitro Effects of Two Bleaching Treatments on Human Enamel Hardness.

    Science.gov (United States)

    Henn-Donassollo, Sandrina; Fabris, Cristiane; Gagiolla, Morgana; Kerber, Ícaro; Caetano, Vinícius; Carboni, Vitor; Salas, Mabel Miluska Suca; Donassollo, Tiago Aurélio; Demarco, Flávio Fernando

    2016-01-01

    The aim of this study was to evaluate in vitro and in situ the effects of two bleaching treatments on human enamel surface microhardness. Sixty enamel slabs from recently extracted thirty molars were used. The specimens were polished with sandpapers under water-cooling. The enamel samples were randomly divided in four groups, treated with 10% hydrogen peroxide (HP) or Whitening Strips (WS) containing 10% hydrogen peroxide and using two conditions: in vitro or in situ model. For in situ condition, six volunteers wore an intra-oral appliance containing enamel slabs, while for in vitro condition the specimens were kept in deionized water after the bleaching protocols. The bleaching treatments were applied one-hour daily for 14 days. Similar amounts of bleaching agents were used in both conditions. Before and after bleaching treatments, microhardness was measured. Statistical analysis (ANOVA and Tukey test) showed that in the in situ condition there was no statistically significant microhardness reduction in the bleached enamel (p>0.05). Significant decrease in hardness was observed for enamel slabs bleached with both treatments in the in vitro condition (phardness value. It could be concluded that there was no deleterious effect on enamel produced by any of the bleaching protocols used in the in situ model. The reduction of hardness was only observed in vitro.

  9. Antifungal activity of allylamines against agents of eumycetoma

    Directory of Open Access Journals (Sweden)

    Venugopal Pankajalakshmi

    1993-01-01

    Full Text Available The antifungal activity of the two allylamines naftifine and terbinafine was investigated against 22 strains of eumycetes isolated from cases of eumycetoma by agar dilution. The isolates included Madurella mycetomatis (4, M. Grisea (8, Pyrenochaeta romeroi (2, Exophiala jeanselmei (2 and Leptosphaeria tompkinsii (1 from black grain eumycetomas and Pseudalescheria boydii (3 Acremonium kiliense (1 and A. recifei (1 form pale grain eumycetomas. Terbinafine was more active than naftifine inhibiting 50% (MIC50 and 90% (MIC90 of the black grain eumycetoma agents at 0.5 and 2.5 ?g/ml respectively. The MIC50s and MIC90s of naftifine were 1 and 5 ?g/ml. For pale grain eumycetoma agents, the MIC range for terbinafine and naftifine were ??0.01 - 100 and 0.1 - 100 ?g/ml.

  10. PENYAMAKAN KULIT IKAN NILA (Oreochromis sp.) DENGAN PERLAKUAN PEMUCATAN (BLEACHING) MENGGUNAKAN PEROKSIDA

    OpenAIRE

    Hak, Nurul

    2016-01-01

    Research for tanning fish skin nile (Oreochromis sp.) on bleaching treatment has been done. Concentration of peroxide as bleaching agent variated in 2, 4, and 6% (v/w) and non bleaching process as a control. As a nile Leather product research characterized trough physic parameter, chemical and organoleptic analysis. Result of nile leather product the optimal amount of peroxide was 4% which resulted in tensile strength of 205 kg/cm2, elongation of 84,67%, sewing strength of 117,29%, and rigid t...

  11. Effect of two different tooth bleaching techniques on microhardness of giomer

    OpenAIRE

    Kimyai, Soodabeh; Bahari, Mahmoud; Naser-Alavi, Fereshteh; Behboodi, Soodabeh

    2017-01-01

    Background Tooth bleaching is a safe and conservative treatment modality to improve the esthetic appearance of discolored teeth. One of the problems with the use of bleaching agents is their possible effect on surface microhardness of resin-based materials. The present study was carried out to evaluate the effect of in-office and at-home bleaching on surface microhardness of giomer. Material and Methods Seventy-five disk-shaped giomer samples (Beautifil II) were prepared and cured with a ligh...

  12. Effect of coffe and a cola-based soft drink on the color stability of bleached bovine incisors considering the time elapsed after bleaching

    Science.gov (United States)

    PIROLO, Rodrigo; MONDELLI, Rafael Francisco Lia; CORRER, Gisele Maria; GONZAGA, Carla Castiglia; FURUSE, Adilson Yoshio

    2014-01-01

    There is no consensus about the waiting time necessary for the patient to start consuming beverages containing colorants again after bleaching. Objective: To evaluate the influence of beverages with coloring agents on bleached bovine incisors considering the time elapsed after bleaching. Materials and methods: Sixty bovine incisors were bleached with 35% hydrogen peroxide for in-office use (Whiteness HP Max) and divided into 10 groups. The color was evaluated with a spectrophotometer (Spectro Shade MICRO) before and after bleaching, employing the CIE-Lab system. After bleaching, the teeth were exposed for 5 min to coffee or cola-based soft drink (CBSD) at different periods after bleaching: 10 min, 1 h, 24 h, 48 h, and 72 h. Color (∆E) and lightness (∆L) variations were obtained from the CIE-Lab coordinates. Data were subjected to two-way ANOVA and Tukey HSD tests (p<0.05). Results: Significant differences were observed between groups for both the ∆L and ∆E values (p<0.001). All specimens presented a decrease in brightness (negative ∆L). The highest ∆E values were observed for teeth stained with a CBSD at 10 min and 1 h (4.12 and 4.16, respectively). Teeth pigmented with coffee presented ∆E values below 3.3 units for all evaluation times. Conclusion: The exposure to coffee after bleaching causes less color changes than the exposure to a CBSD regardless of the time after bleaching. PMID:25075672

  13. Effect of coffe and a cola-based soft drink on the color stability of bleached bovine incisors considering the time elapsed after bleaching

    Directory of Open Access Journals (Sweden)

    Rodrigo PIROLO

    2014-12-01

    Full Text Available There is no consensus about the waiting time necessary for the patient to start consuming beverages containing colorants again after bleaching. Objective: To evaluate the influence of beverages with coloring agents on bleached bovine incisors considering the time elapsed after bleaching. Materials and methods: Sixty bovine incisors were bleached with 35% hydrogen peroxide for in-office use (Whiteness HP Max and divided into 10 groups. The color was evaluated with a spectrophotometer (Spectro Shade MICRO before and after bleaching, employing the CIE-Lab system. After bleaching, the teeth were exposed for 5 min to coffee or cola-based soft drink (CBSD at different periods after bleaching: 10 min, 1 h, 24 h, 48 h, and 72 h. Color (∆E and lightness (∆L variations were obtained from the CIE-Lab coordinates. Data were subjected to two-way ANOVA and Tukey HSD tests (p<0.05. Results: Significant differences were observed between groups for both the ∆L and ∆E values (p<0.001. All specimens presented a decrease in brightness (negative ∆L. The highest ∆E values were observed for teeth stained with a CBSD at 10 min and 1 h (4.12 and 4.16, respectively. Teeth pigmented with coffee presented ∆E values below 3.3 units for all evaluation times. Conclusion: The exposure to coffee after bleaching causes less color changes than the exposure to a CBSD regardless of the time after bleaching.

  14. A comparison of chlorinated organic material produced by chlorine and chlorine dioxide bleaching

    Energy Technology Data Exchange (ETDEWEB)

    McKaque, A.B.; Reeve, D.W. [Univ. of Toronto (Canada)

    1995-12-31

    Chlorine and chlorine dioxide react differently with pulp during bleaching and produce different types of organic by-products. The main differences are the large reduction in the amount of AOX (adsorbable organic halogen) in the effluent and EOX (extractable organic halogen) in the pulp. This talk reviews the differences in the amounts and types of chlorinated organic by-products produced by the two different bleaching agents.

  15. The effect of remin pro and MI paste plus on bleached enamel surface roughness.

    Directory of Open Access Journals (Sweden)

    Haleh Heshmat

    2014-04-01

    Full Text Available The growing demand for enhanced esthetic appearance has led to great developments in bleaching products. The exposure of hard tissues of the tooth to bleaching agents can affect the roughness of the enamel surface. The freshly bleached enamel surface exposed to various surface treatments such as fluoride and other remineralizing agents have been assessed in this study. The aim of this experimental study was to compare the effect of Casein Phosphopeptide-Amorphous Calcium Phosphate with Fluoride (MI Paste Plus and Remin Pro on the enamel surface roughness after bleaching.Thirty enamel samples of sound human permanent molars were prepared for this study. After initial roughness measurement with profilometer, the samples were exposed to 37% carbamide peroxide bleaching agent 20 minutes twice, and randomly divided into three groups of ten. In group 1, a CPP-ACPF containing paste (MI Paste Plus and in group 2, Remin Pro were applied to the teeth during a 15 day period for 5 minutes, twice a day. Samples of group 3 (control were immersed in artificial saliva for 15 days. The roughness of all samples were measured at the beginning, after bleaching and after the study intervention and statistically analyzed.The surface roughness significantly increased in all groups following bleaching, and then it showed a decrease after application of both Remin Pro and CPP-ACPF in comparison to using bleaching agent (P0.05.There was no difference between surface roughness of MI Paste Plus and Remin Pro groups. Also the surface roughness was decreased compared to the initial enamel surface roughness.

  16. Hypoglycemic agents and potential anti-inflammatory activity

    Directory of Open Access Journals (Sweden)

    Kothari V

    2016-04-01

    Full Text Available Vishal Kothari,1 John A Galdo,2 Suresh T Mathews3 1Department of Nutrition and Dietetics, Boshell Diabetes and Metabolic Diseases Research Program, Auburn University, Auburn, 2Department of Pharmacy Practice, 3Department of Nutrition and Dietetics, Samford University, Birmingham, AL, USA Abstract: Current literature shows an association of diabetes and secondary complications with chronic inflammation. Evidence of these immunological changes include altered levels of cytokines and chemokines, changes in the numbers and activation states of various leukocyte populations, apoptosis, and fibrosis during diabetes. Therefore, treatment of diabetes and its complications may include pharmacological strategies to reduce inflammation. Apart from anti-inflammatory drugs, various hypoglycemic agents have also been found to reduce inflammation that could contribute to improved outcomes. Extensive studies have been carried out with thiazolidinediones (peroxisome proliferator-activated receptor- agonist, dipeptidyl peptidase-4 inhibitors, and metformin (AMP-activated protein kinase activator with each of these classes of compounds showing moderate-to-strong anti-inflammatory action. Sulfonylureas and alpha glucosidase inhibitors appeared to exert modest effects, while the injectable agents, insulin and glucagon-like peptide-1 receptor agonists, may improve secondary complications due to their anti-inflammatory potential. Currently, there is a lack of clinical data on anti-inflammatory effects of sodium–glucose cotransporter type 2 inhibitors. Nevertheless, for all these glucose-lowering agents, it is essential to distinguish between anti-inflammatory effects resulting from better glucose control and effects related to intrinsic anti-inflammatory actions of the pharmacological class of compounds. Keywords: diabetes, inflammation, insulin, metformin, thiazolidinedione, gliptin

  17. 21 CFR 582.1975 - Bleached beeswax.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Bleached beeswax. 582.1975 Section 582.1975 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1975 Bleached beeswax. (a) Product. Bleached beeswax (white wax). (b) Conditions of...

  18. Perspective of surface active agents in baking industry: an overview.

    Science.gov (United States)

    Ahmad, Asif; Arshad, Nazish; Ahmed, Zaheer; Bhatti, Muhammad Shahbaz; Zahoor, Tahir; Anjum, Nomana; Ahmad, Hajra; Afreen, Asma

    2014-01-01

    Different researchers have previously used surfactants for improving bread qualities and revealed that these compounds result in improving the quality of dough and bread by influencing dough strength, tolerance, uniform crumb cell size, and improve slicing characteristics and gas retention. The objective of this review is to highlight the areas where surfactants are most widely used particularly in the bread industries, their role and mechanism of interaction and their contribution to the quality characteristics of the dough and bread. This review reveals some aspects of surface-active agents regarding its role physiochemical properties of dough that in turn affect the bread characteristics by improving its sensory quality and storage stability.

  19. Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey proteins.

    Science.gov (United States)

    Listiyani, M A D; Campbell, R E; Miracle, R E; Dean, L O; Drake, M A

    2011-09-01

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations in dried whey products. No legal limit exists in the United States for BP use in whey, but international concerns exist. The objectives of this study were to determine the effect of hydrogen peroxide (HP) or BP bleaching on the flavor of 34% WPC (WPC34) and to evaluate residual BA in commercial and experimental WPC bleached with and without BP. Cheddar whey was manufactured in duplicate. Pasteurized fat-separated whey was subjected to hot bleaching with either HP at 500 mg/kg, BP at 50 or 100 mg/kg, or no bleach. Whey was ultrafiltered and spray dried into WPC34. Color [L*(lightness), a* (red-green), and b* (yellow-blue)] measurements and norbixin extractions were conducted to compare bleaching efficacy. Descriptive sensory and instrumental volatile analyses were used to evaluate bleaching effects on flavor. Benzoic acid was extracted from experimental and commercial WPC34 and 80% WPC (WPC80) and quantified by HPLC. The b* value and norbixin concentration of BP-bleached WPC34 were lower than HP-bleached and control WPC34. Hydrogen peroxide-bleached WPC34 displayed higher cardboard flavor and had higher volatile lipid oxidation products than BP-bleached or control WPC34. Benzoyl peroxide-bleached WPC34 had higher BA concentrations than unbleached and HP-bleached WPC34 and BA concentrations were also higher in BP-bleached WPC80 compared with unbleached and HP-bleached WPC80, with smaller differences than those observed in WPC34. Benzoic acid extraction from permeate showed that WPC80 permeate contained more BA than did WPC34 permeate. Benzoyl peroxide is more effective in color removal of whey and results in fewer flavor side effects compared with HP and residual BA is

  20. Combined ultrasound-laccase assisted bleaching of cotton.

    Science.gov (United States)

    Basto, Carlos; Tzanov, Tzanko; Cavaco-Paulo, Artur

    2007-03-01

    This study evaluates the potential of using ultrasound to enhance the bleaching efficiency of laccase enzyme on cotton fabrics. Ultrasound of low intensity (7W) and relatively short reaction time (30 min) seems to act in a synergistic way with the enzyme in the oxidation/removal of the natural colouring matter of cotton. The increased bleaching effect could be attributed to improved diffusion of the enzyme from the liquid phase to the fibres surface and throughout the textile structure. On the other hand inactivation of the laccase occurred increasing the intensity of the ultrasound. However, at the ultrasound power applied in the bleaching experiments the loss of enzyme activity was not significant enough to justify the use stabilizer such as polyvinyl alcohol. Furthermore, the polyvinyl alcohol appears to be a substrate for the laccase.

  1. Does a toothpaste containing blue covarine have any effect on bleached teeth? An in vitro, randomized and blinded study.

    Science.gov (United States)

    Bortolatto, Janaina Freitas; Dantas, Andrea Abi Rached; Roncolato, Ávery; Merchan, Hugo; Floros, Michael Christopher; Kuga, Milton Carlos; Oliveira Junior, Osmir Batista de

    2016-01-01

    The objective of this study was to analyze the effect of bleaching toothpastes, both conventional and those containing the new whitening agent Blue Covarine, on teeth previously bleached by conventional techniques (in-office and at-home). Squared bovine enamel/dentin blocks (6.0 x 6.0 x 2.0 mm) were randomly distributed in 6 groups (n = 15), according to the technique used to bleach them (in-office: HP35%; at-home: PC10%) and the type of bleaching toothpaste (none: control; Blue Covarine containing: BC; and without Blue Covarine: NBC). Experimental groups denominated HP35%, HP35%BC and HP35%NBC received in-office tooth bleaching before toothbrushing, and groups PC10%, PC10%BC and PC10%NBC were subjected to at-home tooth bleaching prior to toothbrushing. After bleaching treatment, groups HP35%BC, PC10%BC, HP35%NBC and PC10%NBC underwent daily tooth brushing in a brushing machine for 3 minutes (150 strokes/min, with a load of 375 g). Tooth color alteration was measured by reflectance spectroscopy (Vita EasyShade, Vident, Brea, CA, USA) at: T0 (baseline) - after in-office or at-home bleaching treatment; T1 - immediately after tooth brushing; T2 - 7 days and T3 - 14 days after tooth brushing. Data was analyzed by repeated measures mixed ANOVA and the Bonferroni post hoc test, with a significance level of 5%. Statistically significant differences were found between different experimental groups, evaluation times and for the interaction between them (p toothpaste (conventional or with Blue Covarine) showed no color alteration on teeth previously bleached by in-office and at-home tooth bleaching. The use of bleaching toothpastes on previously bleached teeth did not produce a color alteration.

  2. Biological Activities of Phosphocitrate: A Potential Meniscal Protective Agent

    Directory of Open Access Journals (Sweden)

    Yubo Sun

    2013-01-01

    Full Text Available Phosphocitrate (PC inhibited meniscal calcification and the development of calcium crystal-associated osteoarthritis (OA in Hartley guinea pigs. However, the mechanisms remain elusive. This study sought to examine the biological activities of PC in the absence of calcium crystals and test the hypothesis that PC is potentially a meniscal protective agent. We found that PC downregulated the expression of many genes classified in cell proliferation, ossification, prostaglandin metabolic process, and wound healing, including bloom syndrome RecQ helicase-like, cell division cycle 7 homolog, cell division cycle 25 homolog C, ankylosis progressive homolog, prostaglandin-endoperoxide synthases-1/cyclooxygenase-1, and plasminogen activator urokinase receptor. In contrast, PC stimulated the expression of many genes classified in fibroblast growth factor receptor signaling pathway, collagen fibril organization, and extracellular structure organization, including fibroblast growth factor 7, collagen type I, alpha 1, and collagen type XI, alpha 1. Consistent with its effect on the expression of genes classified in cell proliferation, collagen fibril organization, and ossification, PC inhibited the proliferation of OA meniscal cells and meniscal cell-mediated calcification while stimulating the production of collagens. These findings indicate that PC is potentially a meniscal-protective agent and a disease-modifying drug for arthritis associated with severe meniscal degeneration.

  3. A comparison of the bleaching effectiveness of chlorine dioxide and hydrogen peroxide on dental composite.

    Science.gov (United States)

    Agnihotry, Anirudha; Gill, Karanjot S; Singhal, Deepak; Fedorowicz, Zbys; Dash, Sambit; Pedrazzi, Vinicius

    2014-01-01

    This study was carried out to verify if composites could be bleached using chlorine dioxide as compared with hydrogen peroxide. 3M ESPE Filtek Z350 Universal Restorative discs were prepared (n=40), with dimensions 5 mm diameter x 2 mm thickness. The discs were divided into 4 groups of 10 discs each. Color assessment was performed by CIEDE2000. The discs were stained with coffee, tea, wine and distilled water (control) solutions for 14 days, 5 hours daily. Color assessment was repeated on stained discs and followed by bleaching of 5 discs from each group using chlorine dioxide and hydrogen peroxide in-office systems. Finally, a last color assessment was performed and compared statistically. DE2000 after bleaching was very close to baseline for both the bleaching agents, although chlorine dioxide showed better results than hydrogen peroxide. After staining, there was a clinically significant discoloration (∆E2000≥3.43) for the tea, coffee and wine groups, and discoloration (∆E2000) was seen more in the wine group as compared to tea and coffee. Overall, the control group (distilled water) had the least color change in the three intervals. After bleaching, the color in all specimens returned close to the baseline. The color differences between bleaching and baseline were less than 3.43 for all groups. The obtained results show that chlorine dioxide is slightly superior to hydrogen peroxide in the bleaching of composites, while maintaining the shade of the composite close to the baseline.

  4. Effect of newer antioxidants on the bond strength of composite on bleached enamel

    Directory of Open Access Journals (Sweden)

    M Manoharan

    2016-01-01

    Full Text Available Aim: The study aims to evaluate the effect of the application of two antioxidants on the bond strength of composite resin to bleached enamel. Materials and Methods: Eighty enamel surfaces were obtained from forty human extracted premolars. Specimens were randomly divided into four groups (n = 20. Group 1: No bleaching (control; Group 2a: Bleaching with 15% carbamide peroxide gel; Group 2b: Bleaching, followed by application of 10% sodium ascorbate gel; Group 2c: Bleaching, followed by application of 5% proanthocyanidin agent. Surfaces were etched followed by application of total etch bonding system, and composite resin cylinders were bonded. Specimens were tested for shear bond strength. Statistical Analysis Used: One-way analysis of variance was used for multiple group comparison and post hoc Tukey′s test for individual group-wise comparison. Results: Significantly higher shear bond strength values were observed in Group 2c and 2b as compared with Group 1 and 2a (P < 0.05. Among the antioxidants, Group 2c showed significantly higher shear bond strength values than Group 2b (P < 0.05. Conclusion: It can be concluded that the use of antioxidant before bonding procedures on bleached enamel completely neutralizes the deleterious effects of bleaching and increases the bond strength significantly.

  5. Effect of three nanobiomaterials on the surface roughness of bleached enamel

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2015-01-01

    Full Text Available Background: The ever-increasing demand for enhanced esthetic appearance has resulted in significant developments in bleaching products. However, the enamel surface roughness (SR might be negatively affected by bleaching agents. This in vitro study was undertaken to compare the effects of three nanobiomaterials on the enamel SR subsequent to bleaching. Materials and Methods: The crowns of six extracted intact nonerupted human third molars were sectioned. Five dental blocks measuring 2 mm × 3 mm × 4 mm were prepared from each tooth and placed in colorless translucent acrylic resin. The enamel areas from all the specimens were divided into five groups (n = 6: Group 1 did not undergo any bleaching procedures; Group 2 was bleached with a 40% hydrogen peroxide (HP gel; Groups 3, 4, and 5 were bleached with a 40% HP gel modified by bioactive glass (BAG, amorphous calcium phosphate, and hydroxyapatite, respectively. The enamel SR was evaluated before and after treatment by atomic force microscopy. The data were analyzed by Kruskal–Wallis and Mann–Whitney tests. Results: SR increased significantly in the HP group. SR decreased significantly in the HP gel modified by BAG group as compared to other groups. Conclusions: Within the limitations of this study, incorporation of each one of the three test biomaterials proved effective in decreasing enamel SR subsequent to in-office bleaching technique.

  6. Clinical performance of topical sodium fluoride when supplementing carbamide peroxide at-home bleaching gel.

    Science.gov (United States)

    Barcellos, Daphne Camara; Batista, Graziela Ribeiro; da Silva, Melissa Aline; Pleffken, Patricia Rondon; Valera, Marcia Carneiro

    2015-01-01

    This clinical study evaluated the use of 0.11% topical sodium fluoride (SF) desensitizing agent to treat tooth sensitivity during a nightguard tooth whitening procedure. Thirty-two subjects bleached their teeth with 10% carbamide peroxide (CP) gel using an at-home bleaching technique with custom trays. During bleaching treatment, subjects were divided into 2 groups (n = 16). The subjects in Group 1 received a topical gel containing 0.11% SF; the subjects in Group 2 received a placebo gel (PG). Each subject was instructed to place the gel in his/her bleaching tray for 30 min every day following bleaching treatment. Results showed the use of SF did not affect the whitening efficacy of the 10% CP gel. Subjects who received the PG had significantly higher tooth sensitivity when compared with subjects who received SF (P < 0.00). The use of daily 0.11% SF after 10% CP bleaching gel reduced tooth sensitivity during the bleaching treatment.

  7. Effects of bleaching agents on the microleakage of class Ⅴ cavities restored with glass-ionomer cements%漂白剂对玻璃离子水门汀类材料充填Ⅴ类洞边缘微渗漏的影响

    Institute of Scientific and Technical Information of China (English)

    唐健霞; 冯云枝

    2012-01-01

    Objective To evaluate the effects of a bleaching gel and a whitening strip on the microleakage of three different glass-ionomer cements. Methods Forty-five freshly extracted human premolars were used and class V cavity was prepared on the buccal and lingual surfaces. The teeth were randomly assigned to A, B and C groups and restored as follows: Conventional strengthen glass-ionomer cement (Ketac?Molar Easymix), compomer CF2000) and eompomer (Dyract AP). Teeth were kept in distilled water at 37 ? for 7 days. Then the specimens were thermocycled for 500 times. Each group was randomly divided into 3 subgroups which were treated for 21 days with one of the following: Whitening strip (14% hydrogen peroxide), bleaching gel (10% carbamide peroxide), or distilled water (control). After bleaching, the teeth were placed in a solution of basic fuchsin dye for 24 hours, then the teeth were sectioned longitudinally to evaluate the dye penetration. The depth of staining along the tooth restoration interface was recorded with a stereomicroscope. Results There were no signicant differences between the two bleaching agents in microleakage of restorations (ft>0.05\\ The two bleaching agents did not significantly affect the microleakage of compomer (/VO.05), whereas the microleakage of glass-ionomer cement in the experimental groups was higher than that in the control group (P<0.05). Conclusion There are no significant differences in microleakage of restorations between bleaching gel (10% carbamide peroxide) and whitening strip (14% hydrogen peroxide). The two bleaching agents do not significantly affect the microleakage of compomer but adversely affect the microleakage of strengthen glass-ionomer cement.%目的 评估漂白凝胶和洁白牙贴对3种不同的玻璃离子水门汀类材料边缘微渗漏的影响.方法 在45颗离体健康前磨牙的颊舌侧制备V类洞,随机分为A、B、C组,分别使用加强型玻璃离子水门汀KetacTM Molar Easymix,复合体F2000

  8. ActivitySim: large-scale agent based activity generation for infrastructure simulation

    Energy Technology Data Exchange (ETDEWEB)

    Gali, Emmanuel [Los Alamos National Laboratory; Eidenbenz, Stephan [Los Alamos National Laboratory; Mniszewski, Sue [Los Alamos National Laboratory; Cuellar, Leticia [Los Alamos National Laboratory; Teuscher, Christof [PORTLAND STATE UNIV

    2008-01-01

    The United States' Department of Homeland Security aims to model, simulate, and analyze critical infrastructure and their interdependencies across multiple sectors such as electric power, telecommunications, water distribution, transportation, etc. We introduce ActivitySim, an activity simulator for a population of millions of individual agents each characterized by a set of demographic attributes that is based on US census data. ActivitySim generates daily schedules for each agent that consists of a sequence of activities, such as sleeping, shopping, working etc., each being scheduled at a geographic location, such as businesses or private residences that is appropriate for the activity type and for the personal situation of the agent. ActivitySim has been developed as part of a larger effort to understand the interdependencies among national infrastructure networks and their demand profiles that emerge from the different activities of individuals in baseline scenarios as well as emergency scenarios, such as hurricane evacuations. We present the scalable software engineering principles underlying ActivitySim, the socia-technical modeling paradigms that drive the activity generation, and proof-of-principle results for a scenario in the Twin Cities, MN area of 2.6 M agents.

  9. Activity of catalytic silver nanoparticles modulated by capping agent hydrophobicity.

    Science.gov (United States)

    Janani, Seralathan; Stevenson, Priscilla; Veerappan, Anbazhagan

    2014-05-01

    In this paper, a facile in situ method is reported for the preparation of catalytic silver nanoparticles (AgNPs) using N-acyl tyramine (NATA) with variable hydrophobic acyl length. Scanning electron microscopic analysis shows that NATA exists initially as larger aggregates in alkaline aqueous solution. The addition of AgNO3 dissociates these larger aggregate and subsequently promotes the formation of self-assembled NATA and AgNPs. Characterization of AgNPs using UV-vis spectroscopy, scanning electron microscope and transmission electron microscope revealed that the hydrophobic acyl chain length of NATA does not influence the particle size, shape and morphology. All NATA-AgNPs yielded relatively identical values in full width at half-maximum (FWHM) analysis, indicating that the AgNPs prepared with NATA are relatively polydispersed at all tested acyl chain lengths. These nanoparticles are able to efficiently catalyze the reduction of 4-nitro phenol to 4-amino phenol, 2-nitro aniline to 1,2-diamino benzene, 2,4,6-trinitro phenol to 2,4,6-triamino phenol by NaBH4 in an aqueous environment. The reduction reaction rate is determined to be pseudo-first order and the apparent rate constant is linearly dependent on the hydrophobic acyl chain length of the NATA. All reaction kinetics presented an induction period, which is dependent on the N-acyl chain length, indicating that the hydrophobic effects play a critical role in bringing the substrate to the metal nanoparticle surface to induce the catalytic reaction. In this study, however, the five catalytic systems have similar size and polydispersity, differing only in terms of capping agent hydrophobicity, and shows different catalytic activity with respect to the alkyl chain length of the capping agent. As discussed, the ability to modulate the metal nanoparticles catalytic property, by modifying the capping agent hydrophobicity represents a promising future for developing an efficient nanocatalyst without altering the size

  10. Anticancer activity of streptochlorin, a novel antineoplastic agent, in cholangiocarcinoma

    Directory of Open Access Journals (Sweden)

    Kwak TW

    2015-04-01

    Full Text Available Tae Won Kwak,1,* Hee Jae Shin,2,* Young-Il Jeong,1 Myoung-Eun Han,3 Sae-Ock Oh,3 Hyun-Jung Kim,4 Do Hyung Kim,5 Dae Hwan Kang1 1Biomedical Research Institute, Pusan National University Hospital, Busan, 2Marine Natural Products Chemistry Laboratory, Korea Institute of Ocean Science and Technology, Ansan, 3Department of Anatomy, School of Medicine, Pusan National University, Gyeongnam, 4Genewel Co Ltd. Gyeonggi-do, 5School of Medicine, Pusan National University, Yangsan, Gyeongnam, Republic of Korea *These authors contributed equally to this work Background: The aim of this study is to investigate the anticancer activity of streptochlorin, a novel antineoplastic agent, in cholangiocarcinoma. Methods: The anticancer activity of streptochlorin was evaluated in vitro in various cholangiocarcinoma cell lines for apoptosis, proliferation, invasiveness, and expression of various protein levels. A liver metastasis model was prepared by splenic injection of HuCC-T1 cholangiocarcinoma cells using a BALB/c nude mouse model to study the systemic antimetastatic efficacy of streptochlorin 5 mg/kg at 8 weeks. The antitumor efficacy of subcutaneously injected streptochlorin was also assessed using a solid tumor xenograft model of SNU478 cells for 22 days in the BALB/c nude mouse. Results: Streptochlorin inhibited growth and secretion of vascular endothelial growth factor by cholangiocarcinoma cells in a dose-dependent manner and induced apoptosis in vitro. In addition, streptochlorin effectively inhibited invasion and migration of cholangiocarcinoma cells. Secretion of vascular endothelial growth factor and activity of matrix metalloproteinase-9 in cholangiocarcinoma cells were also suppressed by treatment with streptochlorin. Streptochlorin effectively regulated metastasis of HuCC-T1 cells in a mouse model of liver metastasis. In a tumor xenograft study using SNU478 cells, streptochlorin significantly inhibited tumor growth without changes in body weight

  11. SEQUESTERING AGENTS FOR ACTIVE CAPS - REMEDIATION OF METALS AND ORGANICS

    Energy Technology Data Exchange (ETDEWEB)

    Knox, A; Michael Paller, M; Danny D. Reible, D; Xingmao Ma, X; Ioana G. Petrisor, I

    2007-05-10

    This research evaluated organoclays, zeolites, phosphates, and a biopolymer as sequestering agents for inorganic and organic contaminants. Batch experiments were conducted to identify amendments and mixtures of amendments for metal and organic contaminants removal and retention. Contaminant removal was evaluated by calculating partitioning coefficients. Metal retention was evaluated by desorption studies in which residue from the removal studies was extracted with 1 M MgCl{sub 2} solution. The results indicated that phosphate amendments, some organoclays, and the biopolymer, chitosan, were very effective sequestering agents for metals in fresh and salt water. Organoclays were very effective sorbents for phenanthrene, pyrene, and benzo(a)pyrene. Partitioning coefficients for the organoclays were 3000-3500 ml g{sup -1} for benzo(a)pyrene, 400-450 ml g{sup -1} for pyrene, and 50-70 ml g{sup -1} for phenanthrene. Remediation of sites with a mixture of contaminants is more difficult than sites with a single contaminant because metals and organic contaminants have different fate and transport mechanisms in sediment and water. Mixtures of amendments (e.g., organoclay and rock phosphate) have high potential for remediating both organic and inorganic contaminants under a broad range of environmental conditions, and have promise as components in active caps for sediment remediation.

  12. Reuse of discarded deactivated bleaching earth in the bleaching of oils

    Directory of Open Access Journals (Sweden)

    Girgis, Adel Y.

    2005-03-01

    Full Text Available Discarded bleaching earth was used after its reactivation for the bleaching of sunflower, soybean and corn oils. The efficiency of reactivated bleaching earth was compared to the efficiency of virgin activated bleaching earth. Acid reactivated earth (pH 2.5-3 had a slightly higher content in silicone than virgin activated or neutralized reactivated earths. The best results in the color of sunflower and corn oils were obtained when neutralized earth (pH 6–7 was used at 1 and 2 % levels. Acid reactivated earth used at 2 % achieved a higher reduction in soybean oil color than virgin earth (pH 3 at the same dosage. Both reactivated earths reduced peroxide value, iron, conjugated dienes and soap, while they increased acidity and conjugated trienes. Furthermore, these reactivated earths determined higher decrements in the oil induction period than virgin earth. Reactivated earth could be used for 5 cycles for the bleaching of soybean or corn oils and for more than 6 cycles for sunflower oil.Tierra decolorante desechada, fue empleada, tras su reactivación para decolorar aceites de girasol, soja y maíz. La eficiencia de la tierra decolorante reactivada fue comparada con la de la virgen activada. La tierra reactivada ácida (pH 2,5–3 tuvo ligeramente mayor contenido en silicona que la tierra virgen o la reactivada neutra. Los mejores resultados en el color de los aceites de girasol y maíz fueron obtenidos cuando se emplearon niveles del 1 y 2 % de tierra reactivada neutra (pH 6-7. La tierra ácida reactivada, usada al 2 % consiguió una mayor reducción del color del aceite de soja, que una misma dosis de tierra virgen (pH 3. Ambas tierras reactivadas redujeron el índice de peróxidos, hierro, dienos conjugados y jabón de los aceites, mientras que hicieron aumentar la acidez y los trienos conjugados. Además, estas tierras reactivadas determinaron mayores descensos en los periodos de inducción del aceite que la tierra virgen. Las tierras

  13. Influence of Enamel Thickness on Bleaching Efficacy: An In-Depth Color Analysis

    Science.gov (United States)

    Públio, Juliana do Carmo; D’Arce, Maria Beatriz Freitas; Catelan, Anderson; Ambrosano, Gláucia Maria Bovi; Aguiar, Flávio Henrique Baggio; Lovadino, José Roberto; Lima, Débora Alves Nunes Leite

    2016-01-01

    This study evaluated the influence of different enamel thicknesses and bleaching agents on treatment efficacy in-depth by spectrophotometry color analysis. Eighty bovine dental fragments were previously stained in black tea solution and randomly assigned into eight groups (n=10), 1.75mm dentin thickness and different enamel thicknesses as follows: 0.5mm, 1.0mm planned, 1.0mm unplanned (aprismatic enamel), and absence of enamel. The 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching gels were applied on the enamel surface following the manufacturer's recommendations. Color of underlying dentin was evaluated at four times: after staining with tea (baseline) and after each one of the three weeks of bleaching treatment, by CIE L*a*b* system using reflectance spectrophotometer (CM 700d, Konica Minolta). The ΔE, ΔL, Δa, and Δb values were recorded and subjected to repeated measures ANOVA and Tukey’s test (α=0.05). The results showed an increase on lightness (L*), with decreased redness (a*) and yellowness (b*). At first and second week, bleaching with CP showed higher whitening effectiveness compared to bleaching with HP and the presence of aprismatic enamel significantly reduced ΔE for bleaching with CP. After three weeks of bleaching, few differences were observed between CP and HP groups, and outer enamel layer caused no influence on bleaching effectiveness. Overall, both at-home and in-office bleaching treatments were effective and the presence of aprismatic enamel did not interfere on the whitening efficacy. PMID:27708725

  14. Effect of tooth-bleaching on the carbonate concentration in dental enamel by Raman spectroscopy

    Science.gov (United States)

    Vargas-Koudriavtsev, Tatiana; Herrera-Sancho, Óscar-Andrey

    2017-01-01

    Background There are not many studies evaluating the effects of surface treatments at the molecular level. The aim of this in vitro study was to analyze the concentration of carbonate molecules in dental enamel by Raman spectroscopy after the application of in-office and home whitening agents. Material and Methods Sixty human teeth were randomly divided into six groups and exposed to three different home bleaching gels (Day White) and three in-office whitening agents (Zoom! Whitespeed and PolaOffice) according to the manufacturer´s instructions. The concentration of carbonate molecules in enamel was measured prior to and during the treatment by means of Raman spectroscopy. Statistical analysis included repeated measures analysis of variance (p≤0.05) and Bonferroni pairwise comparisons. Results At home bleaching agents depicted a decrease in the carbonate molecule. This decrease was statistically significant for the bleaching gel with the highest hydrogen peroxide concentration (p≤0,05). In-office whitening agents caused an increase in carbonate, which was significant for all three groups (p≤0,05). Conclusions In-office bleaching gels seem to cause a gain in carbonate of the enamel structure, whilst at-home whitening gels caused a loss in carbonate. Key words:Bleaching, whitening, hydrogen peroxide, carbamide peroxide, Raman spectroscopy, carbonate.

  15. Bleaching of leaf litter and associated microfungi in subboreal and subalpine forests.

    Science.gov (United States)

    Hagiwara, Yusuke; Matsuoka, Shunsuke; Hobara, Satoru; Mori, Akira S; Hirose, Dai; Osono, Takashi

    2015-10-01

    Fungal decomposition of lignin leads to the whitening, or bleaching, of leaf litter, especially in temperate and tropical forests, but less is known about such bleaching in forests of cooler regions, such as boreal and subalpine forests. The purposes of the present study were to examine the extent of bleached area on the surface of leaf litter and its variation with environmental conditions in subboreal and subalpine forests in Japan and to examine the microfungi associated with the bleaching of leaf litter by isolating fungi from the bleached portions of the litter. Bleached area accounted for 21.7%-32.7% and 2.0%-10.0% of total leaf area of Quercus crispula and Betula ermanii, respectively, in subboreal forests, and for 6.3% and 18.6% of total leaf area of B. ermanii and Picea jezoensis var. hondoensis, respectively, in a subalpine forest. In subboreal forests, elevation, C/N ratio and pH of the FH layer, and slope aspect were selected as predictor variables for the bleached leaf area. Leaf mass per area and lignin content were consistently lower in the bleached area than in the nonbleached area of the same leaves, indicating that the selective decomposition of acid unhydrolyzable residue (recalcitrant compounds such as lignin, tannins, and cutins) enhanced the mass loss of leaf tissues in the bleached portions. Isolates of a total of 11 fungal species (6 species of Ascomycota and 5 of Basidiomycota) exhibited leaf-litter-bleaching activity under pure culture conditions. Two fungal species (Coccomyces sp. and Mycena sp.) occurred in both subboreal and subalpine forests, which were separated from each other by approximately 1100 km.

  16. Influence of dental bleaching on marginal leakage of Class V restorations

    Directory of Open Access Journals (Sweden)

    Andréia Cristina Ramos Dorini

    2010-04-01

    Full Text Available Objective: Evaluate the in vitro effect of bleaching performed in the dental office and waiting time on the degree of microleakage in class V cavities with margins in enamel, restored with resin composite. Methods: Forty-five human third molars were used, in which the vestibular faces were bleached with 35% hydrogen peroxide activated with LED and the palatine faces were not bleached (control. The teeth were randomly divided into 3 groups with 15 teeth in each: Group 1, restored immediately after bleaching; Group 2, seven days after bleaching; and Group 3, fourteen days after bleaching. After cavity preparation, 35% phosphoric acid, Adper Single Bond 2 adhesive (3M ESPE, St. Paul, Mn, USA, and resin composite Filtek Z250 (3M ESPE, St. Paul, MN, USA were applied. The teeth were thermal cycled and sealed with red nail polish on the bleached faces and blue on the non bleached faces, except for 1mm around the restored region. The samples were classified according to the following scores: 0 = no leakage, 1 = minimum leakage (less than 1 / 3 the length of the wall, 2 = moderate leakage (1/3 to 2/3 of the wall and 3 = extensive leakage (over 2/3 of the wall. The data were submitted to the Kruskal-Wallis test at a level of significance of 5%. Results: The restorative procedure immediately after bleaching resulted in statistically higher microleakage values (p 0.05. Conclusion: Based on the results, it is advisable to wait at least 7 days after bleaching to make the definitive restoration.

  17. Bleaching and recovery patterns of corals in Palk Bay, India: An indication of bleaching resilient reef

    Digital Repository Service at National Institute of Oceanography (India)

    Manikandan, B.; Ravindran, J.; Vidya, P.J.; ManiMurali, R.

    Frequency and severity of coral bleaching events increased in recent years affecting the recovery and resilience of corals. In this study, influence of bleaching and recovery patterns of corals on the resilience potential of Palk Bay reef...

  18. Prediction Model of Antibacterial Activities for Inorganic Antibacterial Agents Based on Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    刘雪峰; 张利; 涂铭旌

    2004-01-01

    Quantitatively evaluation of antibacterial activities of inorganic antibacterial agents is an urgent problem to be solved. Using experimental data by an orthogonal design, a prediction model of the relation between conditions of preparing inorganic antibacterial agents and their antibacterial activities has been developed. This is accomplished by introducing BP artificial neural networks in the study of inorganic antibacterial agents..It provides a theoretical support for the development and research on inorganic antibacterial agents.

  19. Modeling chlorine dioxide bleaching of chemical pulp

    OpenAIRE

    Tarvo, Ville

    2010-01-01

    This doctoral thesis deals with the phenomenon-based modeling of pulp bleaching. Previous bleaching models typically utilize one or two empirical correlations to predict the kinetics in kappa number development. Empirical correlations are simple to develop, but their parameters are often tied to the validation system. A major benefit of physico-chemical phenomenon models is that they are valid regardless of the reaction environment. Furthermore, modeling the bleaching processes at molecular l...

  20. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

    ZhongLiu; Y.Ni; Z.Li,G.Court

    2004-01-01

    Peroxide bleaching is an essential unit operation toproduce value-added mechanical pulp-based papergrade. In this paper, we presented the results fromperoxide bleaching of low-freeness TMP for theproduction of SC paper. Two aspects wereaddressed; the effect of pulp strength and theformation of anionic trashes. The strength properties,such as tensile, burst and zero-span tensile, areimproved after the peroxide bleaching process. Theamount of anionic trashes formed is almostproportional to the hydrogen peroxide charge.

  1. RAFT microemulsion polymerization with surface-active chain transfer agent

    Science.gov (United States)

    El-Hedok, Ibrahim Adnan

    The work described in this dissertation focuses on enhancing the polymer nanoparticle synthesis using RAFT (reversible-addition fragmentation chain transfer) in microemulsion polymerization in order to achieve predetermined molecular weight with narrow molecular weight polydispersity. The hypothesis is that the use of an amphiphilic chain transfer agent (surface-active CTA) will confine the CTA to the surface of the particle and thermodynamically favor partitioning of the CTA between micelles and particles throughout the polymerization. Thus, the CTA diffusion from micelles to polymer particles would be minimized and the breadth of the CTA per particle distribution would remain low. We report the successful improved synthesis of poly(butyl acrylate), poly(ethyl acrylate), and poly(styrene) nanoparticles using the RAFT microemulsion polymerization with surface-active CTA. The polymerization kinetics, polymer characteristics and latex size experimental data are presented. The data analysis indicates that the CTA remains partitioned between the micelles and particles by the end of the polymerization, as expected. We also report the synthesis of well-defined core/shell poly(styrene)/poly(butyl acrylate) nanoparticle, having polydispersity index value of 1.1, using semi-continuous microemulsion polymerization with the surface-active CTA. The surface-active CTA restricts the polymerization growth to the surface of the particle, which facilitates the formation of a shell block co-polymers with each subsequent second monomer addition instead of discrete homopolymers. This synthesis method can be used to create a wide range of core/shell polymer nanoparticles with well-defined morphology, given the right feeding conditions.

  2. Effects of home bleaching on surface hardness and surface roughness of an experimental nanocomposite

    OpenAIRE

    Ab-Ghani Zuryati; Ooi Qian Qian; Mohamad Dasmawati

    2013-01-01

    Objective: Home bleaching agents may not be safe for composite resins. The purpose of this study was to evaluate the effects of 10 and 20% Opalescence ® PF home bleaching agents on the surface roughness and hardness of universal nanocomposite (Filtek Z350), anterior nanocomposite (KeLFiL), and nanohybrid composite (TPH 3). Materials and Methods: Fifty-four composite resin samples with 18 samples for each type of composite resin were prepared using acrylic molds (4 × 2 mm). Each type of co...

  3. Differential gene expression during thermal stress and bleaching in the Caribbean coral Montastraea faveolata.

    Science.gov (United States)

    DeSalvo, M K; Voolstra, C R; Sunagawa, S; Schwarz, J A; Stillman, J H; Coffroth, M A; Szmant, A M; Medina, M

    2008-09-01

    The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographical scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a complementary DNA microarray containing 1310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. In a second experiment, we identified differentially expressed genes during a time course experiment with four time points across 9 days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca(2+) homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first medium-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca(2+) homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis.

  4. THE EFFECTS OF HOME BLEACHING ON THE HARDNESS OF AMALGAM FILLING

    Directory of Open Access Journals (Sweden)

    Andi Soufyan

    2015-06-01

    Full Text Available Dental bleaching has been considered as a feasible approach for dental esthetic, and many dental bleaching products can be seen in the market. Therefore, the side effect of such dental product should be studied. This study was aimed to determine the effect of carbamide peroxide-containing home bleaching agent on the hardness of dental amalgam surface structure. Forty amalgam filling specimens were divided into 4 groups, which consist of 3 treatment groups and 1 controu group. Each group was exposed to the bleaching agent daily for 2, 4 and 8 hours within 7 days. The Vickers Microhardness Tester, with loads 98.07 mN for 20 seconds, was used to measure the hardness of amalgam surface. It was revealed that, there was a significant difference between the treatment and the control group on 8 hours period. It was concluded that there was a decrease in hardness of dental amalgam surface after having a contact with carbamide peroxide bleaching agent.

  5. Effect of temperature and concentration on benzoyl peroxide bleaching efficacy and benzoic acid levels in whey protein concentrate.

    Science.gov (United States)

    Smith, T J; Gerard, P D; Drake, M A

    2015-11-01

    Much of the fluid whey produced in the United States is a by-product of Cheddar cheese manufacture and must be bleached. Benzoyl peroxide (BP) is currently 1 of only 2 legal chemical bleaching agents for fluid whey in the United States, but benzoic acid is an unavoidable by-product of BP bleaching. Benzoyl peroxide is typically a powder, but new liquid BP dispersions are available. A greater understanding of the bleaching characteristics of BP is necessary. The objective of the study was to compare norbixin destruction, residual benzoic acid, and flavor differences between liquid whey and 80% whey protein concentrates (WPC80) bleached at different temperatures with 2 different benzoyl peroxides (soluble and insoluble). Two experiments were conducted in this study. For experiment 1, 3 factors (temperature, bleach type, bleach concentration) were evaluated for norbixin destruction using a response surface model-central composite design in liquid whey. For experiment 2, norbixin concentration, residual benzoic acid, and flavor differences were explored in WPC80 from whey bleached by the 2 commercially available BP (soluble and insoluble) at 5 mg/kg. In liquid whey, soluble BP bleached more norbixin than insoluble BP, especially at lower concentrations (5 and 10 mg/kg) at both cold (4°C) and hot (50°C) temperatures. The WPC80 from liquid whey bleached with BP at 50°C had lower norbixin concentration, benzoic acid levels, cardboard flavor, and aldehyde levels than WPC80 from liquid whey bleached with BP at 4°C. Regardless of temperature, soluble BP destroyed more norbixin at lower concentrations than insoluble BP. The WPC80 from soluble-BP-bleached wheys had lower cardboard flavor and lower aldehyde levels than WPC80 from insoluble-BP-bleached whey. This study suggests that new, soluble (liquid) BP can be used at lower concentrations than insoluble BP to achieve equivalent bleaching and that less residual benzoic acid remains in WPC80 powder from liquid whey

  6. Tropical cyclone cooling combats region-wide coral bleaching.

    Science.gov (United States)

    Carrigan, Adam D; Puotinen, Marji

    2014-05-01

    Coral bleaching has become more frequent and widespread as a result of rising sea surface temperature (SST). During a regional scale SST anomaly, reef exposure to thermal stress is patchy in part due to physical factors that reduce SST to provide thermal refuge. Tropical cyclones (TCs - hurricanes, typhoons) can induce temperature drops at spatial scales comparable to that of the SST anomaly itself. Such cyclone cooling can mitigate bleaching across broad areas when well-timed and appropriately located, yet the spatial and temporal prevalence of this phenomenon has not been quantified. Here, satellite SST and historical TC data are used to reconstruct cool wakes (n=46) across the Caribbean during two active TC seasons (2005 and 2010) where high thermal stress was widespread. Upon comparison of these datasets with thermal stress data from Coral Reef Watch and published accounts of bleaching, it is evident that TC cooling reduced thermal stress at a region-wide scale. The results show that during a mass bleaching event, TC cooling reduced thermal stress below critical levels to potentially mitigate bleaching at some reefs, and interrupted natural warming cycles to slow the build-up of thermal stress at others. Furthermore, reconstructed TC wave damage zones suggest that it was rare for more reef area to be damaged by waves than was cooled (only 12% of TCs). Extending the time series back to 1985 (n = 314), we estimate that for the recent period of enhanced TC activity (1995-2010), the annual probability that cooling and thermal stress co-occur is as high as 31% at some reefs. Quantifying such probabilities across the other tropical regions where both coral reefs and TCs exist is vital for improving our understanding of how reef exposure to rising SSTs may vary, and contributes to a basis for targeting reef conservation.

  7. Biochemical methane potential of kraft bleaching effluent and codigestion with other in-mill streams

    DEFF Research Database (Denmark)

    Fitamo, Temesgen Mathewos; Dahl, Olli; Master, Emma;

    2016-01-01

    and in combination: total bleaching effluent, alkaline bleaching effluent, kraft evaporator condensate, and chemithermomechanical pulping effluent. The total bleaching effluent, consisting of the chlorine dioxide bleaching and alkaline bleaching effluents, exhibited the highest potential for organic matter...

  8. Bleaching induced tooth sensitivity: do the existing enamel craze lines increase sensitivity? A clinical study.

    Science.gov (United States)

    Özcan, Mutlu; Abdin, Sam; Sipahi, Cumhur

    2014-07-01

    The aim of this clinical study was to evaluate whether or not an association exists between the presence of enamel craze lines and the prevalence of tooth sensitivity (TS) after in-office bleaching. Subjects that met the inclusion criteria (N = 23) were screened to detect the existence of enamel craze lines. In total, 460 teeth were subjected to bleaching where 49% of them presented enamel craze lines. After bleaching (15% hydrogen peroxide), the subjects were asked to rate the level of TS by answering a self-administered questionnaire. The majority of subjects (91%) experienced TS at the first day of bleaching. The TS prevalence decreased gradually to 22% at second day, to 17% at third day, and to 9% at fourth day. After the fourth day, no subject reported TS. While 15% of teeth with craze lines presented TS, 11% of teeth with no craze lines also showed TS. A positive but weak correlation (r = 0.214) was found between the existence of enamel craze lines and TS. In this clinical study, higher incidence of TS was found with the use of 15% hydrogen peroxide bleaching agent compared to the previous studies. Patients who would undergo in-office bleaching should be informed that tooth sensitivity is a very often side effect but it may disappear within 1 week.

  9. A bleaching earth from egyptian local deposits

    Directory of Open Access Journals (Sweden)

    El Kinawy, Omayma S.

    2001-10-01

    Full Text Available The present investigation deals with the bleaching of vegetable oils using activated clays collected from some deposits in Egypt as compared to Tonsil FF currently used by local oil industry. The comparison was made; not only on the basis of the decolourising power of the earth, but also on the basis of its effects on the oil acidity, formation of the oil peroxides and the decomposition rate of the formed peroxides to aldehydes and ketones during the bleaching process. The activation of the collected earth samples was made using 4N HCl, 6N HCl and 30 % H2SO4. The bleaching tests of the activated samples were performed using the major four oil types processed in Egypt being cottonseed, sunflower, soybean and palm oils. In addition to the laboratory-evaluation tests, the performance of the activated samples, which showed promise on the lab-scale have been also tested on an industrial scale. The industrial application has proved that the activated local earth's can be successfully used as bleaching earth of local oils. Thus it can be used as a substitute of the varieties currently imported and used by the local oil sector.La presente investigación trata de la decoloración de aceites vegetales usando tierras activadas obtenidas de yacimientos egipcios, comparándola con el Tonsil FF usado normalmente en la industria oleícola local. La comparación se realizó, no sólo sobre la base del poder decolorante de la tierra, sino también sobre la base de sus efectos en la acidez del aceite, la formación de peróxidos y la velocidad de descomposición de los peróxidos formados en aldehidos y cetonas durante el proceso de decoloración. La activación de las muestras de tierras recogidas se hizo utilizando ClH 4N, ClH 6N y H2SO4 30 %. Los tests de decoloración de las muestras activadas se llevaron a cabo usando los cuatro tipos mayoritarios de aceites procesados en Egipto: aceite de semilla de algodón, de girasol, de soja y de palma. Además de los

  10. Effect of different restorative procedures on the fracture resistance of teeth submitted to internal bleaching

    Directory of Open Access Journals (Sweden)

    Andiara Ribeiro Roberto

    2012-02-01

    Full Text Available The aim of this study was to evaluate the influence of different restorative procedures on the fracture resistance of endodontically treated teeth submitted to intracoronal bleaching. Fifty upper central incisors were distributed into 5 groups: GI - healthy teeth; GII - endodontically treated teeth sealed with Coltosol; GIII - endodontically treated teeth bleached and sealed with Coltosol; GIV - endodontically treated teeth bleached and restored with composite resin; and GV - endodontically treated teeth bleached and restored with a fiberglass post and composite resin. In the bleached specimens, a cervical seal was made prior to bleaching with 38% hydrogen peroxide. The gel was applied on the buccal surface and in the pulp chamber, and was then light-activated for 45 s. This procedure was repeated three times per session for four sessions, and each group was submitted to the restorative procedures described above. The specimens were submitted to fracture resistance testing in a universal testing machine. There were statistically significant differences among the groups (p 0.05. The restorative procedures using composite resin were found to successfully restore the fracture resistance of endodontically treated and bleached teeth.

  11. Effect of postoperative bleaching on microleakage of etch-and-rinse and self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Vajihesadat Mortazavi

    2011-01-01

    Full Text Available Background: Bleaching the discoloured teeth may affect the tooth/composite interface. The aim of this in vitro experimental study was to evaluate the effect of vital tooth bleaching on microleakage of existent class V composite resin restorations bonded with three dental bonding agents. Methods : Class V cavities were prepared on buccal surfaces of 72 intact, extracted human anterior teeth with gingival margins in dentin and occlusal margins in enamel, and randomly divided into 3 groups. Cavities in the three groups were treated with Scotch bond Multi-Purpose, a total etch system and Prompt L-Pop and iBond, two self-etch adhesives. All teeth were restored with Z250 resin composite material and thermo-cycled. Each group was equally divided into the control and the bleached subgroups (n = 12. The bleached subgroups were bleached with 15% carbamide peroxide gel for 8 hours a day for 15 days. Microleakage scores were evaluated on the incisal and cervical walls. Data were analyzed using Kruskal-Wallis, Mann-Whitney and Bonferroni post-hoc tests (α = 0.05. Results: Bleaching with carbamide peroxide gel significantly increased the microleakage of composite restorations in Prompt L-Pop group at dentinal walls (P = 0.001. Bleaching had no effect on microleakage of restorations in the Scotch bond Multi-Purpose and iBond groups. Conclusion: Vital tooth bleaching with carbamide peroxide gel has an adverse effect on marginal seal of dentinal walls of existent composite resin restorations bonded with prompt L-Pop self-etch adhesive.

  12. Clinical evaluation of a new bleaching product "Polanight" in a Japanese population.

    Science.gov (United States)

    Tsubura, Shuichi; Yamaguchi, Ryuji

    2005-09-01

    Home bleaching techniques have been applied as a safe and effective bleaching procedure. Many manufacturers are now marketing home tooth-bleaching products. The purpose of this study was to compare a new bleaching product, Polanight (PN) with a widely used home bleaching product, Opalescence (OP). Fifty-eight healthy Japanese volunteers of both sexes (18 to 47 years of age) were selected. Using a simultaneous split-mouth protocol, custom-made trays with PN and OP were applied to the maxillary right anterior teeth and left anterior teeth, respectively. The shades of the maxillary canine teeth were measured with a portable chromameter (Shade Eye Ex) at the first examination and at 4 weeks (after 2-week bleaching and 2-week rest). Tooth shade changes were analyzed using the Commission Internationale d'Eclairage (CIE) Lab units. Means of whiteness-blackness difference (DeltaL*), redness-greenness difference (Deltaa*), and yellowness-blueness difference (Deltab*) were 4.00, -1.28 and -7.53 for PN, and 2.54, -0.99, and -5.56 for OP, respectively. Means of color difference (DeltaE*) were 9.23 and 7.78 for PN and OP, respectively. Treatment with either agent demonstrated significant bleaching effects produced by the treatment. The new product, PN, showed significant differences in DeltaL* (P < 0.05) and Deltab* (P < 0.005), but not in the redness-greenness (a*) value when compared with OP. Bleaching with PN was considered more effective than that with OP in the young patient group and in the women.

  13. Detection of Sulfatase Enzyme Activity with a CatalyCEST MRI Contrast Agent.

    Science.gov (United States)

    Sinharay, Sanhita; Fernández-Cuervo, Gabriela; Acfalle, Jasmine P; Pagel, Mark D

    2016-05-01

    A chemical exchange saturation transfer (CEST) MRI contrast agent has been developed that detects sulfatase enzyme activity. The agent produces a CEST signal at δ=5.0 ppm before enzyme activity, and a second CEST signal appears at δ=9.0 ppm after the enzyme cleaves a sulfate group from the agent. The comparison of the two signals improved detection of sulfatase activity.

  14. Vascular targeting agents enhance chemotherapeutic agent activities in solid tumor therapy.

    Science.gov (United States)

    Siemann, Dietmar W; Mercer, Emma; Lepler, Sharon; Rojiani, Amyn M

    2002-05-01

    The utility of combining the vascular targeting agents 5,6-dimethyl-xanthenone-4 acetic acid (DMXAA) and combretastatin A-4 disodium phosphate (CA4DP) with the anticancer drugs cisplatin and cyclophosphamide (CP) was evaluated in experimental rodent (KHT sarcoma), human breast (SKBR3) and ovarian (OW-1) tumor models. Doses of the vascular targeting agents that led to rapid vascular shutdown and subsequent extensive central tumor necrosis were identified. Histologic evaluation showed morphologic damage of tumor cells within a few hours after treatment, followed by extensive hemorrhagic necrosis and dose-dependent neoplastic cell death as a result of prolonged ischemia. Whereas these effects were induced by a range of CA4DP doses (10-150 mg/kg), the dose response to DMXAA was extremely steep; doses or = 20 mg/kg were toxic. DMXAA also enhanced the tumor cell killing of cisplatin, but doses > 15 mg/kg were required. In contrast, CA4DP increased cisplatin-induced tumor cell killing at all doses studied. This enhancement of cisplatin efficacy was dependent on the sequence and interval between the agents. The greatest effects were achieved when the vascular targeting agents were administered 1-3 hr after cisplatin. When CA4DP (100 mg/kg) or DMXAA (17.5 mg/kg) were administered 1 hr after a range of doses of cisplatin or CP, the tumor cell kill was 10-500-fold greater than that seen with chemotherapy alone. In addition, the inclusion of the antivascular agents did not increase bone marrow stem cell toxicity associated with these anticancer drugs, thus giving rise to a therapeutic gain.

  15. Salt, chloride, bleach, and innate host defense.

    Science.gov (United States)

    Wang, Guoshun; Nauseef, William M

    2015-08-01

    Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense.

  16. pH-Sensitive Microparticles with Matrix-Dispersed Active Agent

    Science.gov (United States)

    Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor); Calle, Luz M. (Inventor)

    2014-01-01

    Methods to produce pH-sensitive microparticles that have an active agent dispersed in a polymer matrix have certain advantages over microcapsules with an active agent encapsulated in an interior compartment/core inside of a polymer wall. The current invention relates to pH-sensitive microparticles that have a corrosion-detecting or corrosion-inhibiting active agent or active agents dispersed within a polymer matrix of the microparticles. The pH-sensitive microparticles can be used in various coating compositions on metal objects for corrosion detecting and/or inhibiting.

  17. Shear Bond Strength of Resin Bonded to Bleached Enamel Using Different Modified 35% Hydrogen Peroxides

    Directory of Open Access Journals (Sweden)

    Moosavi H

    2015-12-01

    Full Text Available Statement of Problem: Bleaching systems with different concentrations and applications are widely used to improve the visual appearance of the teeth, but one of the complications of these materials is reduction of bond strength for immediately bonding to the bleached enamel. Objectives: The aim of this study was to evaluate the influence of using different modified hydrogen peroxide bleaching agents on the shear bond strength of composite resin bonded to the bleached enamel. Materials and Methods: Forty-eight sound extracted premolar teeth were collected, sectioned 1 mm below the CEJ to detach the root. The proximal surfaces of the teeth were flattened using diamond disks and silicon carbide papers to achieve flat homogeneous enamel surfaces without exposure to the dentin. The teeth were randomly divided into four groups as follows (n = 12: group 1: bleaching with 35% hydrogen peroxide gel; group 2: bleaching with 35% hydrogen peroxide gel contained (casein phosphopeptide-amorphous calcium phosphate (CPP-ACP; group 3: bleaching with 35% hydrogen peroxide gel combined with fluoride; and group 4: bleaching with 35% hydrogen peroxide applying one week before resin restoration placement. Composite resin, Clearfil AP-X (Kuraray, Tokyo, Japan, was bonded on each tooth in the mould (4 mm diameter × 3 mm height using Clearfil SE Bond (Kuraray, Tokyo, Japan. After 24 hours of storage and 1000 cycles of thermocycling, the shear bond strength of the specimens at a cross-head speed of 0.5 mm/min was measured in MPa. Data were analyzed using ANOVA and Tukey’s post-hoc test. Results: The minimum and maximum mean shear bond strength values were observed in groups 2 (15.82 ± 4.41 and 4 (21.00 ± 3.90, respectively. Multiple comparisons of groups revealed no significant differences among the groups except between group 4 and all the other groups. The most common type of failure was adhesive. Conclusions: Using modified bleaching agents decreased the bond

  18. Synthesis, Antifungal Activities and Qualitative Structure Activity Relationship of Carabrone Hydrazone Derivatives as Potential Antifungal Agents

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-03-01

    Full Text Available Aimed at developing novel fungicides for relieving the ever-increasing pressure of agricultural production caused by phytopathogenic fungi, 28 new hydrazone derivatives of carabrone, a natural bioactive sesquisterpene, in three types were designed, synthesized and their antifungal activities against Botrytis cinerea and Colletotrichum lagenarium were evaluated. The result revealed that all the derivatives synthesized exhibited considerable antifungal activities in vitro and in vivo, which led to the improved activities for carabrone and its analogues and further confirmed their potential as antifungal agents.

  19. Erosion and abrasion on dental structures undergoing at-home bleaching

    Directory of Open Access Journals (Sweden)

    Tarquinio SBC

    2011-07-01

    Full Text Available Flávio Fernando Demarco1, Sônia Saeger Meireles2, Hugo Ramalho Sarmento1, Raquel Venâncio Fernandes Dantas1, Tatiana Botero3, Sandra Beatriz Chaves Tarquinio11Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Brazil; 2Department of Operative Dentistry, Federal University of Paraíba, Brazil; 3Cariology, Restorative Science, and Endodontics Department, School of Dentistry, University of Michigan, MI, USAAbstract: This review investigates erosion and abrasion in dental structures undergoing at-home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled.Keywords: peroxide, tooth bleaching, enamel, dentin, erosion, abrasion

  20. Low temperature bleaching of cotton cheese with peroxide activator TAED%纯棉筒子纱的低温活化氧漂处理

    Institute of Scientific and Technical Information of China (English)

    师文钊; 邢建伟; 任支刚; 徐成书; 刘瑾姝

    2013-01-01

    针对纯棉筒子纱传统高温煮漂前处理工艺存在能耗大和纤维损伤等问题,采用氧漂活化剂四乙酰乙二胺(TAED)对筒子纱进行低温前处理.考察了双氧水和TAED用量、氢氧化钠用量和处理温度及时间对纱线白度、毛效和强力的影响,并与传统前处理工艺进行比较.结果表明,纯棉筒子纱低温前处理优化工艺为:NaOH 2 g/L,H2O2 (30%)6 g/L,TAED 6 g/L,升温至60℃处理10 min,再升温至80℃处理30 m in.采用优化工艺处理后,纱线的断裂强力明显高于传统前处理工艺,白度和毛效相当,而工艺时间和流程大幅缩短.%Aiming at the high energy consumption and fiber damage in traditional high-temperature scouring and bleaching pre-treatment of cotton cheese, low-temperature pretreatment process with tetra acetyl ethylene diamine(TAED) is introduced. The effect of dosages of hydrogen peroxide and TAED, caustic soda, temperature and time on whiteness, capillary effect and tensile strength is ciscussed and compared with that of traditional process. The results show that the optimal process conditions are NaOH 2 g/L, H2O2(30%) 6 g/L, TAED 6 g/L, treating at 60 ℃ for 10 min, and then holding at 80 ℃ for 30 min. The yarns pretreated wth optimal process feature higher breaking strength, similar whiteness and capillary effect, shortened process time and procedure.

  1. 过氧化脲漂白剂对树脂修复体边缘微渗漏影响的实验研究%Effect of carbamide peroxide bleaching agents on micro-leakage of composite resin interface in vitro

    Institute of Scientific and Technical Information of China (English)

    王晓玲; 徐娟; 赵信义; 何惠明

    2011-01-01

    Objective To evaluate the effect of carbamide peroxide (CP) bleaching agents at different concentrations and with different carriers on the micro-leakage of composite resin interface. Methods Class V cavity (2 mm in diameter and 2 mm in depth) preparations were made at the enamelo-cemental junction on the buccal and lingual surfaces of 35 extracted human premolars. The cavities were filled with hybrid composite resin. The teeth were stored for 24 h in distilled water at 37°C before thermocyling for 500 times between 5 and 55 °C. The teeth were then randomly assigned into 7 groups, and in groups 1-6, the bleaching gels containing 10% or 20% of CP were applied on the buccal and lingual surface of the teeth for two weeks (6-8 h/day, 37 °C, 100% relative humidity) using Carbopol, PVP or Poloxamer as the thickening carriers, respectively. The seventh group served as the control without bleaching treatment. Nail polish was applied to the surface of the tooth, and all the teeth were immersed in ammoniacal silver nitrate solution followed by developing solution. The teeth were finally sectioned through the midline of the restoration and observed under stereomicroscope. SEM micrographs were also made to observe the interface. Results With the same bleaching agent, the micro-leakage in the gingival wall was slightly greater than in the occlusive wall, but the difference was not significant. Only 20% CP with Poloxamer as the thickening agent significantly increased the leakage of dentine-resin composite interface, and 10% and 20% CP with Carbopol or PVP as the thickening agents and 10% CP with Poloxamer produced minimal effects on filling the micro-leakage. Conclusion Thickening carriers and the concentration of CP (20% or below) have no significant effect on micro-leakage of composite resin.%目的 评价以不同载体配制的不同浓度过氧化脲(CP)漂白剂对复合树脂边缘微渗漏的影响.方法 在35颗离体前磨牙颊舌面牙颈部制备V类洞(直径2

  2. The Activation of Free Dipeptides Promoted by Strong Activating Agents in Water Does not Yield Diketopiperazines.

    Science.gov (United States)

    Beaufils, Damien; Jepaul, Sandra; Liu, Ziwei; Boiteau, Laurent; Pascal, Robert

    2016-03-01

    The activation of dipeptides was studied in the perspective of the abiotic formation of oligopeptides of significant length as a requirement for secondary structure formation. The formation of piperazin-2,5-diones (DKP), previously considered as a dead end when activating free dipeptides, was shown in this work to be efficiently suppressed when using strong activating agents (e.g., carbodiimides). This behaviour was explained by the fast formation of a 5(4H)-oxazolone intermediate at a rate that exceeds the time scale of the rotation of the peptide bond from the predominant trans-conformation into the cis-isomer required for DKP formation. No DKP was observed when using strong activating agents whereas phosphate mixed anhydrides or moderately activated esters were observed to predominantly yield DKP. The DKP side-reaction no longer constitutes a drawback for the C-terminus elongation of peptides. These results are considered as additional evidence that pathways involving strong activation are required to drive the emergence of living entities rather than close to equilibrium processes.

  3. Morphology and optical properties of aluminum oxide formed into oxalic electrolyte with addition surface active agents

    Science.gov (United States)

    Kazarkin, B.; Stsiapanau, A.; Zhilinski, V.; Chernik, A.; Bezborodov, V.; Kozak, G.; Danilovich, S.; Smirnov, A.

    2016-08-01

    The article discusses the results of investigations of porous films of alumina, formed into oxalic electrolyte with addition surface active agents, in particular, ordering structure, roughness of a surface, the optical transparency of the electrolyte concentration and surface active agents. Also discusses the features of the formation of porous films of temperature and IR radiation.

  4. Optical Emission Spectroscopy of an Atmospheric Pressure Plasma Jet During Tooth Bleaching Gel Treatment.

    Science.gov (United States)

    Šantak, Vedran; Zaplotnik, Rok; Tarle, Zrinka; Milošević, Slobodan

    2015-11-01

    Optical emission spectroscopy was performed during atmospheric pressure plasma needle helium jet treatment of various tooth-bleaching gels. When the gel sample was inserted under the plasma plume, the intensity of all the spectral features increased approximately two times near the plasma needle tip and up to two orders of magnitude near the sample surface. The color change of the hydroxylapatite pastille treated with bleaching gels in conjunction with the atmospheric pressure plasma jet was found to be in correlation with the intensity of OH emission band (309 nm). Using argon as an additive to helium flow (2 L/min), a linear increase (up to four times) of OH intensity and, consequently, whitening (up to 10%) of the pastilles was achieved. An atmospheric pressure plasma jet activates bleaching gel, accelerates OH production, and accelerates tooth bleaching (up to six times faster).

  5. THE STUDY ON TCF BLEACHING OF NS REED PULP

    Institute of Scientific and Technical Information of China (English)

    Meihong Niu; Shulan Shi; Jinghui Zhou; Yunzhan Zhang

    2004-01-01

    In this paper, we have researched TCF bleaching on reed pulp including oxygen delignification, oxygen delignification with H2O2 intensification and H2O2 bleaching. The results show that Op-P bleaching process on NS reed pulp is suitable and the brightness of bleached pulp is up to 82% ISO.

  6. THE STUDY ON TCF BLEACHING OF NS REED PULP

    Institute of Scientific and Technical Information of China (English)

    MeihongNiu; ShulanShi; JinghuiZhou; YunzhanZhang

    2004-01-01

    In this paper, we have researched TCF bleaching on reed pulp including oxygen delignification, oxygen delignification with H202 intensification and H2O2 bleaching. The results show that Op-P bleaching process on NS reed pulp is suitable and the brightness of bleached pulp is up to 82%ISO.

  7. Microscopic oxygen imaging based on fluorescein bleaching efficiency measurements

    DEFF Research Database (Denmark)

    Beutler, Martin; Heisterkamp, Ines M.; Piltz, Bastian

    2014-01-01

    Photobleaching of the fluorophore fluorescein in an aqueous solution is dependent on the oxygen concentration. Therefore, the time-dependent bleaching behavior can be used to measure of dissolved oxygen concentrations. The method can be combined with epi-fluorescence microscopy. The molecular sta...... concentrations. The method was demonstrated on nitrifying biofilms growing on snail and mussel shells, showing clear effects of metabolic activity on oxygen concentrations. © 2014 Wiley Periodicals, Inc....

  8. Effect of activation agents on the surface chemical properties and desulphurization performance of activated carbon

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Flue gas pollution is a serious environmental problem that needs to be solved for the sustainable development of China.The surface chemical properties of carbon have great influence on its desulphurization performance.A series of activated carbons (ACs) were prepared using HNO3,H2O2,NH3·H2O and steam as activation agents with the aim to introduce functional groups to carbon surface in the ACs preparation process.The ACs were physically and chemically characterized by iodine and SO2 adsorption,ultimate analysis,Boehm titration,and temperature-programmed reduction (TPR).Results showed that the iodine number and desulphurization capacity of NH3·H2O activated carbon (AC-NH3) increase with both activation time,and its desulphurization capacity also increases with the concentration of activation agent.However,HNO3 activated carbon (AC-HNO3) and H2O2 activated carbon (AC-H2O2) exhibit more complex behavior.Only their iodine numbers increase monotonously with activation time.Compared with steam activated AC (AC-H2O),the nitrogen content increases 0.232% in AC-NH3 and 0.077% in AC-HNO3.The amount of total basic site on AC-HNO3 is 0.19 mmol·g-1 higher than that on AC-H2O.H2O2 activation introduces an additional 0.08 mmol·g-1 carboxyl groups to AC surface than that introduced by steam activation.The desulphurization capacity of ACs in simulate flue gas desulphurization decreases as follows: AC-NH3 > AC-HNO3 > AC-H2O2 > AC-H2O.This sequence is in accord with the SO2 catalytic oxidation/oxidation ratio in the absence of oxygen and the oxidation property reflected by TPR.In the presence of oxygen,all adsorbed SO2 on ACs can be oxidized into SO3.The desulphurization capacity increases differently according to the activation agents;the desulphurization capacity of AC-NH3 and AC-HNO3 improves by 4.8 times,yet AC-H2O increases only by 2.62 as compared with the desulphurization of corresponding ACs in absence of oxygen.

  9. Coral bleaching: the role of the host.

    Science.gov (United States)

    Baird, Andrew H; Bhagooli, Ranjeet; Ralph, Peter J; Takahashi, Shunichi

    2009-01-01

    Coral bleaching caused by global warming is one of the major threats to coral reefs. Very recently, research has focused on the possibility of corals switching symbionts as a means of adjusting to accelerating increases in sea surface temperature. Although symbionts are clearly of fundamental importance, many aspects of coral bleaching cannot be readily explained by differences in symbionts among coral species. Here we outline several potential mechanisms by which the host might influence the bleaching response, and conclude that predicting the fate of corals in response to climate change requires both members of the symbiosis to be considered equally.

  10. The role of microorganisms in coral bleaching.

    Science.gov (United States)

    Rosenberg, Eugene; Kushmaro, Ariel; Kramarsky-Winter, Esti; Banin, Ehud; Yossi, Loya

    2009-02-01

    Coral bleaching is the disruption of the symbiosis between the coral host and its endosymbiotic algae. The prevalence and severity of the disease have been correlated with high seawater temperature. During the last decade, the major hypothesis to explain coral bleaching is that high water temperatures cause irreversible damage to the symbiotic algae resulting in loss of pigment and/or algae from the holobiont. Here, we discuss the evidence for an alternative but not mutually exclusive concept, the microbial hypothesis of coral bleaching.

  11. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

    Zhong Liu; Y. Ni; Z. Li; G. Court

    2004-01-01

    Peroxide bleaching is an essential unit operation to produce value-added mechanical pulp-based paper grade. In this paper, we presented the results from peroxide bleaching of low-freeness TMP for the production of SC paper. Two aspects were addressed; the effect of pulp strength and the formation of anionic trashes. The strength properties,such as tensile, burst and zero-span tensile, are improved after the peroxide bleaching process. The amount of anionic trashes formed is almost proportional to the hydrogen peroxide charge.

  12. Mill Designed Bio bleaching Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Institute of Paper Science Technology

    2004-01-30

    A key finding of this research program was that Laccase Mediator Systems (LMS) treatments on high-kappa kraft could be successfully accomplished providing substantial delignification (i.e., > 50%) without detrimental impact on viscosity and significantly improved yield properties. The efficiency of the LMS was evident since most of the lignin from the pulp was removed in less than one hour at 45 degrees C. Of the mediators investigated, violuric acid was the most effective vis-a-vis delignification. A comparative study between oxygen delignification and violuric acid revealed that under relatively mild conditions, a single or a double LMS{sub VA} treatment is comparable to a single or a double O stage. Of great notability was the retention of end viscosity of LMS{sub VA} treated pulps with respect to the end viscosity of oxygen treated pulps. These pulps could then be bleached to full brightness values employing conventional ECF bleaching technologies and the final pulp physical properties were equal and/or better than those bleached in a conventional ECF manner employing an aggressively O or OO stage initially. Spectral analyses of residual lignins isolated after LMS treated high-kappa kraft pulps revealed that similar to HBT, VA and NHA preferentially attack phenolic lignin moieties. In addition, a substantial decrease in aliphatic hydroxyl groups was also noted, suggesting side chain oxidation. In all cases, an increase in carboxylic acid was observed. Of notable importance was the different selectivity of NHA, VA and HBT towards lignin functional groups, despite the common N-OH moiety. C-5 condensed phenolic lignin groups were overall resistant to an LMS{sub NHA, HBT} treatments but to a lesser extent to an LMS{sub VA}. The inactiveness of these condensed lignin moieties was not observed when low-kappa kraft pulps were biobleached, suggesting that the LMS chemistry is influenced by the extent of delignification. We have also demonstrated that the current

  13. Methods for improved selectivity in photo-activation and detection of molecular diagnostic agents

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, Eric A. (Oak Ridge, TN); Fisher, Walter G. (Knoxville, TN); Dees, H. Craig (Knoxville, TN)

    2008-03-18

    A method for the imaging of a particular volume of plant or animal tissue, wherein the plant or animal tissue contains at least one photo-active molecular agent. The method comprises the steps of treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of the photo-active molecular agent contained in the particular volume of the plant or animal tissue, photo-activating at least one of the at least one photo-active molecular agent in the particular volume of the plant or animal tissue, thereby producing at least one photo-activated molecular agent, wherein the at least one photo-activated molecular agent emits energy, detecting the energy emitted by the at least one photo-activated molecular agent, and producing a detected energy signal which is characteristic of the particular volume of plant or animal tissue. The present invention also provides a method for the imaging of a particular volume of material, wherein the material contains at least one photo-active molecular agent.

  14. Method for improved selectivity in photo-activation and detection of molecular diagnostic agents

    Science.gov (United States)

    Wachter, E.A.; Fisher, W.G.; Dees, H.C.

    1998-11-10

    A method for the imaging of a particular volume of plant or animal tissue, wherein the plant or animal tissue contains at least one photo-active molecular agent. The method includes the steps of treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of the photo-active molecular agent contained in the particular volume of the plant or animal tissue, photo-activating at least one of the at least one photo-active molecular agent in the particular volume of the plant or animal tissue, thereby producing at least one photo-activated molecular agent, wherein the at least one photo-activated molecular agent emits energy, detecting the energy emitted by the at least one photo-activated molecular agent, and producing a detected energy signal which is characteristic of the particular volume of plant or animal tissue. The present invention is also a method for the imaging of a particular volume of material, wherein the material contains at least one photo-active molecular agent. 13 figs.

  15. Multi-Agent Active Interaction with Driving Assistance Systems

    OpenAIRE

    Barthès, Jean-Paul,; Bonnifait, Philippe

    2010-01-01

    7 pages; International audience; Intelligent vehicles refer currently to vehicles able to drive autonomously or able to provide pertinent information to the driver for safety, assistance and comfort. Cognitive cars are intelligent vehicles with additional capabilities like being able to collaborate with the driver in operating conditions. In this paper, a multi-agent system is used as a “digital butler” that does the interface between the driver and the machine. In order to test this approach...

  16. Effect of laser-assisted bleaching with Nd:YAG and diode lasers on shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Mirhashemi, Amirhossein; Emadian Razavi, Elham Sadat; Behboodi, Sara; Chiniforush, Nasim

    2015-12-01

    The aim of the present study was to assess the effect of laser-assisted bleaching with neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode lasers on shear bond strength (SBS) of orthodontic brackets. One hundred and four extracted human premolars were randomly divided into four groups: group 1: No bleaching applied (control group); group 2: Teeth bleached with 40 % hydrogen peroxide; group 3: Teeth treated with 30 % hydrogen peroxide activated with Nd:YAG laser (1064 nm, 2.5 W, 25 Hz, pulse duration of 100 μs, 6 mm distance); and group 4: Teeth treated with 30 % hydrogen peroxide activated with diode laser (810 nm, 1 W, CW, 6 mm distance). Equal numbers of teeth in groups 2, 3, and 4 were bonded at start, 1 h, 24 h, and 1 week after bleaching. A universal testing machine measured the SBS of the samples 24 h after bonding. After bracket debonding, the amount of residual adhesive on the enamel surface was observed under a stereomicroscope to determine the adhesive remnant index (ARI) scores. The SBS in the unbleached group was significantly higher than that in the bleached groups bonded immediately and 1 h after laser-assisted bleaching (P laser-assisted bleaching, the SBS was found to be significantly lower than that in the control group. Significant differences in the ARI scores existed among groups as well. The SBS of brackets seems to increase quickly within an hour after laser-assisted bleaching and 24 h after conventional bleaching. Thus, this protocol can be recommended if it is necessary to bond the brackets on the same day of bleaching.

  17. Efficacy of and effect on tooth sensitivity of in-office bleaching gel concentrations: a randomized clinical trial.

    Science.gov (United States)

    Reis, A; Kossatz, S; Martins, G C; Loguercio, A D

    2013-01-01

    With the aim of reducing the side effects of in-office bleaching agents, less-concentrated hydrogen peroxide (HP) gels have been released by manufacturers. We evaluated the tooth sensitivity (TS) and bleaching efficacy (BE) of two HP concentrations in this study. Gels containing 35% and 20% HP (HP35 and HP20, respectively) were applied on teeth of 60 caries-free patients. Color was recorded at baseline and one week after the first and second bleaching sessions using the Vita Classical shade guide. TS was recorded on a 0-4 scale. BE at each weekly recall was evaluated by Kruskall-Wallis and Mann-Whitney tests (α=0.05). Absolute risk of TS and its intensity was evaluated by Fisher exact and Mann-Whitney tests, respectively (α=0.05). After two bleaching sessions, color change of approximately eight tabs was obtained with HP35; whereas, with HP20 it was six tabs (p<0.05). Only 26.7% (HP35) and 16.7% (HP20) of the participants reported TS, and no statistical differences were detected among them. Both in-office bleaching gels showed similar TS intensity, but the 35% HP agent produced faster bleaching.

  18. The effect of baking soda when applied to bleached enamel prior to restorative treatment.

    Science.gov (United States)

    Tostes, Bhenya Ottoni; Mondelli, Rafael Francisco Lia; Lima-Arsati, Ynara Bosco de Oliveira; Rodrigues, Jose Augusto; Costa, Leonardo Cesar

    2013-08-01

    This in vitro study evaluated the effect of 10% baking soda solution and sodium bicarbonate powder (applied with jets) when applied to bleached enamel prior to restorative treatment. The surfaces of 40 bovine incisors were flattened and divided into 5 groups (n = 8): Group B (bleached and restored, negative control), Group W (bleached, stored in distilled water for 7 days, and restored), Group BSJ (bleached, abraded with baking soda jet for 1 min, and restored), Group BSS (bleached, application of 10% baking soda solution for 5 min, and restored), and Group R (restored, without bleaching, positive control). The samples were bleached in 1 session with 3 applications of 35% HP-based gel and activated with a LED appliance for 9 min each. Resin composite cylinders (2 mm height and 0.8 mm diameter) were made on the enamel surface after the acid etching and a conventional 1-step single vial adhesive application was performed. After storage in distilled water (37 ± 1°C, 24 hr), the microshear bond test was performed (1 mm/min). ANOVA and Tukey tests were applied to compare the results. The mean results of these tests showed that Groups W, BBS, and R were not statistically different. These groups also indicated a higher bond strength when compared with Groups B and BSJ. The application of 10% baking soda solution for 5 min may be an alternative pre-restorative treatment for bleached enamel, but further studies are needed to consider whether or not this treatment may be effectively used in clinical practice.

  19. Evaluation of the influence of dental bleaching with 35% hydrogen peroxide in orthodontic bracket shear bond strength

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Neiva Nunes do Rego

    2013-04-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate, in vitro, the bond strength of brackets bonded to premolars previously subjected to bleaching with a 35% hydrogen peroxide. METHODS: Twenty one healthy premolars were selected and randomly divided into three groups (n = 7. Group I (G1 included teeth that were not submitted to bleaching. The enamel surfaces of Groups II (G2 and III (G3 were submitted to a bleaching process with 35% hydrogen peroxide (Whiteness HP Maxx. On Group II (G2, after bleaching, the teeth were stored for 24 hours in distilled water at 98.6 ºF, and then, premolar metallic brackets were bonded using Transbond XT (3M resin. Group III (G3 was submitted to the same procedure seven days after bleaching. After bonding, all teeth were stored in distilled water at 98.6 ºF for 24 hours. All groups were submitted to a traction test using an EMIC DL2000 universal testing machine at a speed of 0.5 mm/min. RESULTS AND CONCLUSION: The bracket resistance to debonding was compared between the groups by the Kruskal-Wallis nonparametric test (p < 0.05 and it was verified that the bleaching agent significantly reduced bracket adhesion when bonded 24 hours after bleaching. However, seven days after bleaching, there was no significant difference on the resistance to debonding among groups G1 (19,52 kgf and G3 (18,44 kgf, meaning that it is necessary to wait longer after bleaching to bond brackets.

  20. A strategic framework for responding to coral bleaching events in a changing climate.

    Science.gov (United States)

    Maynard, J A; Johnson, J E; Marshall, P A; Eakin, C M; Goby, G; Schuttenberg, H; Spillman, C M

    2009-07-01

    The frequency and severity of mass coral bleaching events are predicted to increase as sea temperatures continue to warm under a global regime of rising ocean temperatures. Bleaching events can be disastrous for coral reef ecosystems and, given the number of other stressors to reefs that result from human activities, there is widespread concern about their future. This article provides a strategic framework from the Great Barrier Reef to prepare for and respond to mass bleaching events. The framework presented has two main inter-related components: an early warning system and assessment and monitoring. Both include the need to proactively and consistently communicate information on environmental conditions and the level of bleaching severity to senior decision-makers, stakeholders, and the public. Managers, being the most timely and credible source of information on bleaching events, can facilitate the implementation of strategies that can give reefs the best chance to recover from bleaching and to withstand future disturbances. The proposed framework is readily transferable to other coral reef regions, and can easily be adapted by managers to local financial, technical, and human resources.

  1. A Strategic Framework for Responding to Coral Bleaching Events in a Changing Climate

    Science.gov (United States)

    Maynard, J. A.; Johnson, J. E.; Marshall, P. A.; Eakin, C. M.; Goby, G.; Schuttenberg, H.; Spillman, C. M.

    2009-07-01

    The frequency and severity of mass coral bleaching events are predicted to increase as sea temperatures continue to warm under a global regime of rising ocean temperatures. Bleaching events can be disastrous for coral reef ecosystems and, given the number of other stressors to reefs that result from human activities, there is widespread concern about their future. This article provides a strategic framework from the Great Barrier Reef to prepare for and respond to mass bleaching events. The framework presented has two main inter-related components: an early warning system and assessment and monitoring. Both include the need to proactively and consistently communicate information on environmental conditions and the level of bleaching severity to senior decision-makers, stakeholders, and the public. Managers, being the most timely and credible source of information on bleaching events, can facilitate the implementation of strategies that can give reefs the best chance to recover from bleaching and to withstand future disturbances. The proposed framework is readily transferable to other coral reef regions, and can easily be adapted by managers to local financial, technical, and human resources.

  2. Evaluation of the effects of conventional versus laser bleaching techniques on enamel microroughness.

    Science.gov (United States)

    Anaraki, Saeid Nemati; Shahabi, Sima; Chiniforush, Nasim; Nokhbatolfoghahaei, Hanieh; Assadian, Hadi; Yousefi, Bahareh

    2015-04-01

    Nowadays, bleaching of the teeth within the dental office is one of the most widespread techniques to correct tooth discoloration. Variability of the materials and techniques accompanied with the trend toward esthetic restorations with minimally invasive approaches are increasing. The use of laser in this regard has also been taken into consideration. The aim of this study was to evaluate the effects of in-office versus laser bleaching on surface roughness of enamel. Fifteen freshly extracted human molars were sectioned mesiodistally to produce 30 lingual and buccal enamel blocks. Samples were mounted in transparent acrylic resin blocks and polished before treatment. Samples were randomly assigned to laser bleaching (LB) and office bleaching (OB) groups (n = 15 each). Pretreatment evaluation of microroughness was carried out for all samples using profilometer. Samples were treated twice in the OB group with Opalescent Xtra Boost and in the LB group using a laser-activated gel. Microroughness was evaluated after bleaching in both groups. Data were analyzed using repeated measure ANOVA. Both methods increased enamel surface roughness. Microroughness changes were significantly different between the two groups (p  0.05), but there was no significant difference in pre- and post-treatment roughness evaluation in the LB group (p roughness increase in comparison with the conventional office bleaching procedure.

  3. An Effective Ostrich Oil Bleaching Technique Using Peroxide Value as an Indicator

    Directory of Open Access Journals (Sweden)

    Gan Seng Chiew

    2011-07-01

    Full Text Available Ostrich oil has been used extensively in the cosmetic and pharmaceutical industries. However, rancidity causes undesirable chemical changes in flavour, colour, odour and nutritional value. Bleaching is an important process in refining ostrich oil. Bleaching refers to the removal of certain minor constituents (colour pigments, free fatty acid, peroxides, odour and non-fatty materials from crude fats and oils to yield purified glycerides. There is a need to optimize the bleaching process of crude ostrich oil prior to its use for therapeutic purposes. The objective of our study was to establish an effective method to bleach ostrich oil using peroxide value as an indicator of refinement. In our study, we showed that natural earth clay was better than bentonite and acid-activated clay to bleach ostrich oil. It was also found that 1 hour incubation at a 150 °C was suitable to lower peroxide value by 90%. In addition, the nitrogen trap technique in the bleaching process was as effective as the continuous nitrogen flow technique and as such would be the recommended technique due to its cost effectiveness.

  4. Rhamnolipids as active protective agents for microorganisms against toxic substances

    Directory of Open Access Journals (Sweden)

    Marta Woźniak

    2012-12-01

    Full Text Available The presence of microbial biosurfactants decreases the toxicity of chlorophenols towards Pseudomonas putida 2A cells. The rhamnolipid-originating micelles selectively entrapped chlorophenol molecules, which resulted in their lower bioavailability to microbial cells. It was observed that the effective concentrations causing 50% growth inhibition increased by 0.5, 0.35 and 0.15 for phenol, 4-chlorophenol and 2.4-dichlorophenol, accordingly. The application of surfactants as protective agents for microorganisms brings about new possibilities of using this phenomenon in bioremediation techniques.

  5. Method for improved selectivity in photo-activation of molecular agents

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, W.G.; Wachter, E.A.; Dees, H.C.

    2000-03-28

    An apparatus is disclosed for the treatment of a particular volume of plant or animal tissue by treating the plant or animal tissue with at least one photo-active molecular agent, wherein the particular volume of the plant or animal tissue retains at least a portion of the at least one photo-active molecular agent. The particular volume of the plant or animal tissue is then treated with light sufficient to promote a simultaneous two-photon excitation of at least one photo-active molecular agent retained in the particular volume of the plant or animal tissue. This results in at least one photo-active molecular agent becoming active in the particular volume of the plant or animal tissue.

  6. Method for improved selectivity in photo-activation of molecular agents

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, W.G.; Wachter, E.A.; Dees, H.C.

    1999-12-07

    This application describes a method for the treatment of a particular volume of plant or animal tissue comprising the steps of treating the tissue with at least one photo-active molecular agent. In this treatment the tissue retains at least a portion of one photo-active molecular agent. Then the tissue is treated with light sufficient to promote a simultaneous two-photon excitation of the photo-active molecular agent, causing it to become active in the plant or animal tissue. There is also disclosed a method for the treatment of cancer in plant or animal tissue and a method for producing at least one photo-activated molecular agent in a particular volume of a material.

  7. Method for improved selectivity in photo-activation of molecular agents

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Walter G. (Knoxville, TN); Wachter, Eric A. (Oak Ridge, TN); Dees, H. Craig (Knoxville, TN)

    2000-01-01

    An apparatus for the treatment of a particular volume of plant or animal tissue by treating the plant or animal tissue with at least one photo-active molecular agent, wherein the particular volume of the plant or animal tissue retains at least a portion of the at least one photo-active molecular agent, and then treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of at least one of the at least one photo-active molecular agent retained in the particular volume of the plant or animal tissue, wherein the at least one photo-active molecular agent becomes active in the particular volume of the plant or animal tissue.

  8. Structure-activity relationship for the reactivators of acetylcholinesterase inhibited by nerve agent VX.

    Science.gov (United States)

    Kuca, Kamil; Musilek, Kamil; Jun, Daniel; Karasova, Jana; Soukup, Ondrej; Pejchal, Jaroslav; Hrabinova, Martina

    2013-08-01

    Nerve agents such as sarin, VX and tabun are organophosphorus compounds able to inhibit an enzyme acetylcholinesterase (AChE). AChE reactivators and anticholinergics are generally used as antidotes in the case of intoxication with these agents. None from the known AChE reactivators is able to reactivate AChE inhibited by all kinds of nerve agents. In this work, reactivation potency of seventeen structurally different AChE reactivators was tested in vitro and subsequently, relationship between their chemical structure and biological activity was outlined. VX was chosen as appropriate member of the nerve agent family.

  9. Symbiophagy as a cellular mechanism for coral bleaching.

    Science.gov (United States)

    Downs, Craig A; Kramarsky-Winter, Esti; Martinez, Jon; Kushmaro, Ariel; Woodley, Cheryl M; Loya, Yossi; Ostrander, Gary K

    2009-02-01

    Coral bleaching is a major contributor to the global declines of coral reefs. This phenomenon is characterized by the loss of symbiotic algae, their pigments or both. Despite wide scientific interest, the mechanisms by which bleaching occurs are still poorly understood. Here we report that the removal of the symbiont during light and temperature stress is achieved using the host's cellular autophagic-associated machinery. Host cellular and subcellular morphologies showed increased vacuolization and appearance of autophagic membranes surrounding a variety of organelles and surrounding the symbiotic algae. Markers of autophagy (Rab 7 and LAS) corroborate these observations. Results showed that during stress the symbiont vacuolar membrane is transformed from a conduit of nutrient exchange to a digestive organelle resulting in the consumption of the symbiont, a process we term symbiophagy. We posit that during a stress event, the mechanism maintaining symbiosis is destabilized and symbiophagy is activated, ultimately resulting in the phenomenon of bleaching. Symbiophagy may have evolved from a more general primordial innate intracellular protective pathway termed xenophagy.

  10. INFLUENCE OF BIOLOGICALLY ACTIVE AGENTS ON A STRUCTURAL STATE AND THE ENZYMATIC ACTIVITY OF BLACK ORDINARY CARBONATED SOIL

    Directory of Open Access Journals (Sweden)

    Lychman V. A.

    2014-04-01

    Full Text Available The results of a long-term research of the influence of various biologically active agents (a humic preparation Lignogumat and microbiological Baikal EM fertilizer on a structural state and the enzymatic activity of ordinary carbonated black soil are presented. It has been established that biologically active substances contribute to increased enzymatic activity, humus and improve the soil structure

  11. Structure-activity study of pentamidine analogues as antiprotozoal agents.

    Science.gov (United States)

    Bakunova, Svetlana M; Bakunov, Stanislav A; Patrick, Donald A; Kumar, E V K Suresh; Ohemeng, Kwasi A; Bridges, Arlene S; Wenzler, Tanja; Barszcz, Todd; Jones, Susan Kilgore; Werbovetz, Karl A; Brun, Reto; Tidwell, Richard R

    2009-04-09

    Diamidine 1 (pentamidine) and 65 analogues (2-66) have been tested for in vitro antiprotozoal activities against Trypanosoma brucei rhodesiense, Plasmodium falciparum, and Leishmania donovani, and for cytotoxicity against mammalian cells. Dications 32, 64, and 66 exhibited antitrypanosomal potencies equal or greater than melarsoprol (IC(50) = 4 nM). Nine congeners (2-4, 12, 27, 30, and 64-66) were more active against P. falciparum than artemisinin (IC(50) = 6 nM). Eight compounds (12, 32, 33, 44, 59, 62, 64, and 66) exhibited equal or better antileishmanial activities than 1 (IC(50) = 1.8 microM). Several congeners were more active than 1 in vivo, curing at least 2/4 infected animals in the acute mouse model of trypanosomiasis. The diimidazoline 66 was the most promising compound in the series, showing excellent in vitro activities and high selectivities against T. b. rhodesiense, P. falciparum, and L. donovani combined with high antitrypanosomal efficacy in vivo.

  12. Effects of home bleaching on surface hardness and surface roughness of an experimental nanocomposite

    Directory of Open Access Journals (Sweden)

    Ab-Ghani Zuryati

    2013-01-01

    Full Text Available Objective: Home bleaching agents may not be safe for composite resins. The purpose of this study was to evaluate the effects of 10 and 20% Opalescence ® PF home bleaching agents on the surface roughness and hardness of universal nanocomposite (Filtek Z350, anterior nanocomposite (KeLFiL, and nanohybrid composite (TPH 3. Materials and Methods: Fifty-four composite resin samples with 18 samples for each type of composite resin were prepared using acrylic molds (4 × 2 mm. Each type of composite resin was further divided into three groups [n = 6 controls were placed in distilled water for 14 days and the other two groups of n = 6 were bleached with 10 and 20% carbamide peroxide (CP, respectively for 14 days]. Surface hardness of the composite resin was tested with a Vickers hardness tester, whereas surface roughness was tested with atomic force microscopy (AFM. Results: There were significant changes in the surface hardness of KeLFiL and TPH 3. However, all the tested materials showed no significant changes in the surface roughness. Conclusion: After 14 days of home bleaching treatment, there was no adverse effect on the surface roughness of all three composite resins, although the surface hardness for KeLFiL and TPH 3 were significantly reduced.

  13. Effects of home bleaching on surface hardness and surface roughness of an experimental nanocomposite

    Science.gov (United States)

    Zuryati, Ab-Ghani; Qian, Ooi Qian; Dasmawati, Mohamad

    2013-01-01

    Objective: Home bleaching agents may not be safe for composite resins. The purpose of this study was to evaluate the effects of 10 and 20% Opalescence® PF home bleaching agents on the surface roughness and hardness of universal nanocomposite (Filtek Z350), anterior nanocomposite (KeLFiL), and nanohybrid composite (TPH 3). Materials and Methods: Fifty-four composite resin samples with 18 samples for each type of composite resin were prepared using acrylic molds (4 × 2 mm). Each type of composite resin was further divided into three groups [n = 6 controls were placed in distilled water for 14 days and the other two groups of n = 6 were bleached with 10 and 20% carbamide peroxide (CP), respectively for 14 days]. Surface hardness of the composite resin was tested with a Vickers hardness tester, whereas surface roughness was tested with atomic force microscopy (AFM). Results: There were significant changes in the surface hardness of KeLFiL and TPH 3. However, all the tested materials showed no significant changes in the surface roughness. Conclusion: After 14 days of home bleaching treatment, there was no adverse effect on the surface roughness of all three composite resins, although the surface hardness for KeLFiL and TPH 3 were significantly reduced. PMID:23956541

  14. Unprecedented mass bleaching and loss of coral across 12° of latitude in Western Australia in 2010-11.

    Directory of Open Access Journals (Sweden)

    James A Y Moore

    Full Text Available BACKGROUND: Globally, coral bleaching has been responsible for a significant decline in both coral cover and diversity over the past two decades. During the summer of 2010-11, anomalous large-scale ocean warming induced unprecedented levels of coral bleaching accompanied by substantial storminess across more than 12° of latitude and 1200 kilometers of coastline in Western Australia (WA. METHODOLOGY/PRINCIPAL FINDINGS: Extreme La-Niña conditions caused extensive warming of waters and drove considerable storminess and cyclonic activity across WA from October 2010 to May 2011. Satellite-derived sea surface temperature measurements recorded anomalies of up to 5°C above long-term averages. Benthic surveys quantified the extent of bleaching at 10 locations across four regions from tropical to temperate waters. Bleaching was recorded in all locations across regions and ranged between 17% (±5.5 in the temperate Perth region, to 95% (±3.5 in the Exmouth Gulf of the tropical Ningaloo region. Coincident with high levels of bleaching, three cyclones passed in close proximity to study locations around the time of peak temperatures. Follow-up surveys revealed spatial heterogeneity in coral cover change with four of ten locations recording significant loss of coral cover. Relative decreases ranged between 22%-83.9% of total coral cover, with the greatest losses in the Exmouth Gulf. CONCLUSIONS/SIGNIFICANCE: The anomalous thermal stress of 2010-11 induced mass bleaching of corals along central and southern WA coral reefs. Significant coral bleaching was observed at multiple locations across the tropical-temperate divide spanning more than 1200 km of coastline. Resultant spatially patchy loss of coral cover under widespread and high levels of bleaching and cyclonic activity, suggests a degree of resilience for WA coral communities. However, the spatial extent of bleaching casts some doubt over hypotheses suggesting that future impacts to coral reefs under

  15. Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial.

    Science.gov (United States)

    Loguercio, Alessandro Dourado; Tay, Lidia Yileng; Herrera, Daniel Rodrigo; Bauer, Jose; Reis, Alessandra

    2015-01-01

    The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE) was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0-4) during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher's exact test (α = 0.05). The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively). BE was also found to be similar between the groups (p = 0.67). Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.

  16. Effects of new formulas of bleaching gel and fluoride application on enamel microhardness: an in vitro study.

    Science.gov (United States)

    da Costa, Juliana B; Mazur, Rui Fernando

    2007-01-01

    This in vitro study evaluated the new formulas of bleaching products and the effect of subsequent applications of fluoride on the hardness of enamel during and after tooth bleaching. The crowns of 60 extracted intact human molars were sectioned longitudinally; the buccal part was embedded in acrylic resin, the occlusal part was ground flat, exposing enamel and dentin, and then polished. Baseline Knoop microhardness (KHN) of enamel was determined. The specimens were then randomly divided into six groups of 10 specimens, and each group was assigned to a specific 10% carbamide peroxide (CP) bleaching agent. A: Opalescence, B: Opalescence PF (3% potassium nitrate and 0.11% fluoride), C: Nite White Excel 3 (ACP), D: Opalescence + F (acidulated phosphate fluoride 1.23%), E: Opalescence PF + F, F: Nite White Excel 3 + F. The teeth were bleached for eight hours; after each procedure, the specimens were stored in artificial saliva at 37 degrees C. Immediately after day 21 of bleaching, the specimens in groups D, E and F received fluoride 1.23% for five minutes. KHN tests w ere performedbefore (baseline = control), during (14, 21) and two weeks (35 days) after the bleaching procedure and were statistically compared using ANOVA/Tukey's t-test (alpha formulas, the enamel was restored to a value similar to baseline.

  17. Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Alessandro Dourado LOGUERCIO

    2015-01-01

    Full Text Available The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0–4 during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher’s exact test (α = 0.05. The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively. BE was also found to be similar between the groups (p = 0.67. Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.

  18. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    OpenAIRE

    Vanhoof, R.; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-01-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) wer...

  19. TRIAZOLE: A POTENTIAL BIOACTIVE AGENT (SYNTHESIS AND BIOLOGICAL ACTIVITY)

    OpenAIRE

    Pandeya Surendra Nath; Pathak Ashish; Mishra Rupesh

    2011-01-01

    Azoles belong to very important class of Antimicrobial drugs. Triazole is very important Azole which exists in two isomeric forms namely 1, 2, 3-Triazole and 1, 2, 4-Triazole. This Review Article covers the Different approaches to synthesize Triazoles having different substitution and their different biological activity. This Review article can be useful to synthesize new compounds having Triazole nucleolus.

  20. Evaluation of antiseptic antiviral activity of chemical agents.

    Science.gov (United States)

    Geller, Chloé; Finance, Chantal; Duval, Raphaël Emmanuel

    2011-06-01

    Antiviral antisepsis and disinfection are crucial for preventing the environmental spread of viral infections. Emerging viruses and associated diseases, as well as nosocomial viral infections, have become a real issue in medical fields, and there are very few efficient and specific treatments available to fight most of these infections. Another issue is the potential environmental resistance and spread of viral particles. Therefore, it is essential to properly evaluate the efficacy of antiseptics-disinfectants (ATS-D) on viruses. ATS-D antiviral activity is evaluated by (1) combining viruses and test product for an appropriately defined and precise contact time, (2) neutralizing product activity, and (3) estimating the loss of viral infectivity. A germicide can be considered to have an efficient ATS-D antiviral activity if it induces a >3 or >4 log(10) reduction (American and European regulatory agency requirements, respectively) in viral titers in a defined contact time. This unit describes a global methodology for evaluating chemical ATS-D antiviral activity.

  1. The northern limit of corals of the genus Acropora in temperate zones is determined by their resilience to cold bleaching.

    Science.gov (United States)

    Higuchi, Tomihiko; Agostini, Sylvain; Casareto, Beatriz Estela; Suzuki, Yoshimi; Yuyama, Ikuko

    2015-12-18

    The distribution of corals in Japan covers a wide range of latitudes, encompassing tropical to temperate zones. However, coral communities in temperate zones contain only a small subset of species. Among the parameters that determine the distribution of corals, temperature plays an important role. We tested the resilience to cold stress of three coral species belonging to the genus Acropora in incubation experiments. Acropora pruinosa, which is the northernmost of the three species, bleached at 13 °C, but recovered once temperatures were increased. The two other species, A. hyacinthus and A. solitaryensis, which has a more southerly range than A. pruinosa, died rapidly after bleaching at 13 °C. The physiological effects of cold bleaching on the corals included decreased rates of photosynthesis, respiration, and calcification, similar to the physiological effects observed with bleaching due to high temperature stress. Contrasting hot bleaching, no increases in antioxidant enzyme activities were observed, suggesting that reactive oxygen species play a less important role in bleaching under cold stress. These results confirmed the importance of resilience to cold stress in determining the distribution and northern limits of coral species, as cold events causing coral bleaching and high mortality occur regularly in temperate zones.

  2. The influence of desensitizing dentifrices on pain induced by in-office bleaching.

    Science.gov (United States)

    Thiesen, Carlos Henrique; Rodrigues Filho, Rubens; Prates, Luiz Henrique Maykot; Sartori, Neimar

    2013-01-01

    The purpose of this study was to evaluate whether the use of desensitizing dentifrices used 15 days prior to and after in-office tooth bleaching could eliminate or reduce tooth sensitivity. After institutional review board approval and informed consent, 45 subjects were selected and divided into 3 groups according to the dentifrice selected: Colgate Total (CT), Colgate Sensitive Pro-Relief (CS) or Sensodyne ProNamel (SP). The subjects used toothpaste and a toothbrush provided to them for 15 days prior to bleaching. They were then submitted to two in-office bleaching sessions (Whiteness HP Blue Calcium). Their tooth sensitivity was assessed using the Visual Analog Scale (VAS) for a week after each session. Their tooth shade alteration was measured with a Vitapan Classical shade guide to determine if the dentifrices could influence the effectiveness of the bleaching agent. The data were submitted to Wilcoxon, Kruskal-Wallis and Mann-Whitney tests (α = 0.05). The use of desensitizing dentifrices did not affect the bleaching efficacy. In regard to tooth sensitivity, there was a statistically significant difference between the results of the Control Group and Group T2 after the first session (p = 0.048). There was no statistically significant difference in the results for the other groups after the first session. In regard to the second session, there was no statistically significant difference in the results for all the groups. The use of a desensitizing dentifrice containing nitrate potassium reduced tooth sensitivity during the bleaching regimen. Dentifrices containing arginine and calcium carbonate did not reduce tooth sensitivity. Color change was not influenced by the dentifrices used.

  3. The influence of desensitizing dentifrices on pain induced by in-office bleaching

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Thiesen

    2013-12-01

    Full Text Available The purpose of this study was to evaluate whether the use of desensitizing dentifrices used 15 days prior to and after in-office tooth bleaching could eliminate or reduce tooth sensitivity. After institutional review board approval and informed consent, 45 subjects were selected and divided into 3 groups according to the dentifrice selected: Colgate Total (CT, Colgate Sensitive Pro-Relief (CS or Sensodyne ProNamel (SP. The subjects used toothpaste and a toothbrush provided to them for 15 days prior to bleaching. They were then submitted to two in-office bleaching sessions (Whiteness HP Blue Calcium. Their tooth sensitivity was assessed using the Visual Analog Scale (VAS for a week after each session. Their tooth shade alteration was measured with a Vitapan Classical shade guide to determine if the dentifrices could influence the effectiveness of the bleaching agent. The data were submitted to Wilcoxon, Kruskal-Wallis and Mann-Whitney tests (α = 0.05. The use of desensitizing dentifrices did not affect the bleaching efficacy. In regard to tooth sensitivity, there was a statistically significant difference between the results of the Control Group and Group T2 after the first session (p = 0.048. There was no statistically significant difference in the results for the other groups after the first session. In regard to the second session, there was no statistically significant difference in the results for all the groups. The use of a desensitizing dentifrice containing nitrate potassium reduced tooth sensitivity during the bleaching regimen. Dentifrices containing arginine and calcium carbonate did not reduce tooth sensitivity. Color change was not influenced by the dentifrices used

  4. NRF2 activation by antioxidant antidiabetic agents accelerates tumor metastasis.

    Science.gov (United States)

    Wang, Hui; Liu, Xiufei; Long, Min; Huang, Yi; Zhang, Linlin; Zhang, Rui; Zheng, Yi; Liao, Xiaoyu; Wang, Yuren; Liao, Qian; Li, Wenjie; Tang, Zili; Tong, Qiang; Wang, Xiaocui; Fang, Fang; Rojo de la Vega, Montserrat; Ouyang, Qin; Zhang, Donna D; Yu, Shicang; Zheng, Hongting

    2016-04-13

    Cancer is a common comorbidity of diabetic patients; however, little is known about the effects that antidiabetic drugs have on tumors. We discovered that common classes of drugs used in type 2 diabetes mellitus, the hypoglycemic dipeptidyl peptidase-4 inhibitors (DPP-4i) saxagliptin and sitagliptin, as well as the antineuropathic α-lipoic acid (ALA), do not increase tumor incidence but increase the risk of metastasis of existing tumors. Specifically, these drugs induce prolonged activation of the nuclear factor E2-related factor 2 (NRF2)-mediated antioxidant response through inhibition of KEAP1-C151-dependent ubiquitination and subsequent degradation of NRF2, resulting in up-regulated expression of metastasis-associated proteins, increased cancer cell migration, and promotion of metastasis in xenograft mouse models. Accordingly, knockdown of NRF2 attenuated naturally occurring and DPP-4i-induced tumor metastasis, whereas NRF2 activation accelerated metastasis. Furthermore, in human liver cancer tissue samples, increased NRF2 expression correlated with metastasis. Our findings suggest that antioxidants that activate NRF2 signaling may need to be administered with caution in cancer patients, such as diabetic patients with cancer. Moreover, NRF2 may be a potential biomarker and therapeutic target for tumor metastasis.

  5. Local stressors reduce coral resilience to bleaching.

    Science.gov (United States)

    Carilli, Jessica E; Norris, Richard D; Black, Bryan A; Walsh, Sheila M; McField, Melanie

    2009-07-22

    Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2-3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change.

  6. On luminescence bleaching of tidal channel sediments

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.

    2015-01-01

    We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels...... and on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... on the quantitative measures of sediment reworking, we suggest that repeated depositional and erosional cycles allow for complete bleaching of the tidal flat sediment, and we infer that quartz OSL dating can provide accurate ages for shallow tidal channel fill....

  7. Hemicellulases in the bleaching of chemical pulps.

    Science.gov (United States)

    Suurnäkki, A; Tenkanen, M; Buchert, J; Viikari, L

    1997-01-01

    Hemicellulase-aided bleaching is the first full-scale biotechnical application in the pulp and paper industry which truly exploits the unique specificity and safety of biocatalysts. Hemicellulases are used to modify the structure of xylan and glucomannan in pulp fibers in order to enhance the chemical delignification. This technology can be combined with various types of kraft pulping processes and bleaching sequences. The aims of the enzymatic treatment depend on the actual mill conditions, and may be related to environmental demands, reduction of chemical costs, or maintenance or even improvement of product quality. The technology is applied on the mill scale in several countries. This review describes the principles of the enzyme-aided bleaching, the composition of the fiber substrates, the basic enzymology involved, and the present knowledge of the mechanisms of the action of enzymes, as well as the practical results and advantages obtained on the laboratory and industrial scale.

  8. Method for improved selectivity in photo-activation of molecular agents

    Science.gov (United States)

    Fisher, W.G.; Wachter, E.A.; Dees, H.C.

    1998-11-03

    A method for the treatment of a particular volume of plant or animal tissue comprising the steps of treating the plant or animal tissue with at least one photo-active molecular agent, wherein the particular volume of the plant or animal tissue retains at least a portion of the at least one photo-active molecular agent, and then treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of at least one of the at least one photo-active molecular agent retained in the particular volume of the plant or animal tissue, wherein the at least one photo-active molecular agent becomes active in the particular volume of the plant or animal tissue. There is also disclosed a method for the treatment of cancer in plant or animal tissue and a method for producing at least one photo-activated molecular agent in a particular volume of a material. 23 figs.

  9. Method for improved selectivity in photo-activation of molecular agents

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Walter G. (Knoxville, TN); Wachter, Eric A. (Oak Ridge, TN); Dees, H. Craig (Knoxville, TN)

    1999-01-01

    A method for the treatment of a particular volume of plant or animal tissue comprising the steps of treating the plant or animal tissue with at least one photo-active molecular agent, wherein the particular volume of the plant or animal tissue retains at least a portion of the at least one photo-active molecular agent, and then treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of at least one of the at least one photo-active molecular agent retained in the particular volume of the plant or animal tissue, wherein the at least one photo-active molecular agent becomes active in the particular volume of the plant or animal tissue. There is also disclosed a method for the treatment of cancer in plant or animal tissue and a method for producing at least one photo-activated molecular agent in a particular volume of a material.

  10. Use of the Malthus-AT system to assess the efficacy of permeabilizing agents on the activity of antibacterial agents against Pseudomonas aeruginosa.

    Science.gov (United States)

    Ayres, H M; Payne, D N; Furr, J R; Russell, A D

    1998-06-01

    The Malthus-AT system provided a satisfactory method for examining the effects of permeabilizing agents on the activity of sub-inhibitory concentrations of antibacterial agents against Pseudomonas aeruginosa G48. Under this system, disodium edetate potentiated the activity of chlorhexidine diacetate (CHA), cetylpyridinium chloride, para-chlorometaxylenol and triclosan. Nitrilotriacetic acid enhanced the activity of some of the antibacterials tested, whereas sodium polyphosphate markedly reduced the efficacy of CHA.

  11. Study on bleaching effect of activated carbon on stevia solution%甜菊糖溶液活性炭脱色工艺研究

    Institute of Scientific and Technical Information of China (English)

    丁红梅; 田洪; 连运河; 牛志平

    2013-01-01

    为解决甜菊糖产品的颜色问题,选用活性炭对甜菊糖苷溶液进行脱色,并对甜菊糖溶液的脱色率和甜菊糖的损失率进行研究.先通过单因素试验初步确定活性炭的添加条件及添加量,在脱色效果达到的情况下针对甜菊糖的损失率进行正交试验,对活性炭添加比例、溶液温度、吸附时间、pH值对溶液脱色率和甜菊糖损失率的影响进行试验,证明各种因素对脱色效果和甜菊糖损失的影响不同,活性炭的添加比例影响因素最大,其次是时间,再次是温度,影响最小的是pH值.单因素试验和正交试验确定最佳工艺条件为:最佳活性炭添加比例为1%,最佳温度10℃,最佳时间为0.5h,最佳pH值为7.0,产品吸光值达到标准要求,甜菊糖损失率为2.72%.%In order to solve the problem of the color of stevia products,the activated carbon was chose to reduce the stevia solution color.The decolorization rate and the loss ratio of stevia sugar were studied.Single factor experiment preliminary determined the adding conditions and adding amount of activated carbon.In the case of decoloring effect to deal with loss of stevia sugar orthogonal experiment,the proportion of adding activated carbon,solution temperature,adsorption time,pH value of solution decoloring rate and loss rate of stevia sugar were experimented.The influence of various factors on the decoloring effect and stevia sugar loss was different.The largest influence was the proportion of adding activated carbon,the followed was time,again was the temperature,the least was pH value.The single factor test and the orthogonal experiment determined the optimum conditions was:activated carbon proportion 1%,temperature 10℃,time 0.5h and the pH value of 7.0.In the case the roduct absorbance value met standard requirements,and the stevia sugar loss rate was 2.72%.

  12. In-Vitro Evaluation of the Effect of Herbal Antioxidants on Shear Bond Strength of Composite Resin to Bleached Enamel

    Directory of Open Access Journals (Sweden)

    Zahra Khamverdi

    2016-11-01

    Full Text Available Objectives: A reduction in bond strength of composite to bleached enamel has been reported immediately after bleaching treatment. Application of some antioxidant agents may decrease the adverse effects of whitening agents on bond strength and enhance composite bond to enamel. This study aimed to assess the effect of green tea, sodium ascorbate, sage and grape seed extract on bond strength of composite to bleached enamel.Materials and Methods: In this in-vitro study, 90 human enamel surfaces were randomly divided into six groups as follows (n=15: G1, no bleaching; G2, bleaching with 40% hydrogen peroxide (HP; G3, HP+1000 μmol epigallocatechin gallate (EGCG for 10 minutes; G4, HP+10% sodium ascorbate for 10 minutes; G5, HP+10% sage for 10 minutes and G6, HP+5% grape seed extract for 10 minutes. The specimens were bonded to composite in all groups. The shear bond strength of specimens was measured in Megapascals (MPa. Data were analyzed using one-way ANOVA and Tukey’s HSD test (α=0.05.Results: The highest and the lowest mean shear bond strength values were observed in group 1 (22.61±3.29MPa and group 2 (5.87±1.80MPa, respectively. The reduction in bond strength in group 2 was greater than that in other groups (P<0.001. No significant difference was found among groups 1, 3, 4, 5 and 6 (P>0.05. Conclusions: All the herbal antioxidants used in this study equally compensated for the reduced bond strength of composite to bleached enamel.Keywords: Antioxidants; Tooth Bleaching; Composite Resins; Shear Strength 

  13. Bleaching and diffusion dynamics in optofluidic dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Asger

    2007-01-01

    The authors have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. They find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules...... pumping devices. ©2007 American Institute of Physics....

  14. Side effects of external tooth bleaching

    DEFF Research Database (Denmark)

    E.M., Bruzell; Pallesen, Ulla; Thoresen, N.R.

    2013-01-01

    -office = 39.3% [n = 28]; p >0.05; 95% CI [OR]: 0.198‑1.102) whereas prevalence of gingival irritation was higher after in-office treatment (at-home = 14.0%; in-office = 35.7%; p ... attributed to the bleaching treatment in the at-home and in-office groups, respectively. Predictors for side effects were tooth sensitivity, surface loss and gingivitis when observed at inclusion. Treatment-related predictors were bleaching concentration and contact between tray and gingiva. Conclusions...

  15. Stability improvement in bleached phase holograms

    Science.gov (United States)

    Kumar, S.; Singh, K.

    1991-08-01

    An experimental study has been made of the influence of developer composition on the stability against the print-out effect of bleached, photographically recorded two-beam interference grating on Agfa-Gevaert 10E75 NAH plates. The diffraction efficiency has been increased by using potassium iodide and an iodine bleach process that converts a silver image into a dielectric image. An improvement in stability against the print-out effect has been observed by using two new developer compositions. Variation of the maximum diffraction efficiency against exposure to white light is shown graphically.

  16. Clonidine as a sensitizing agent in the forced swimming test for revealing antidepressant activity.

    OpenAIRE

    1991-01-01

    The forced swimming test (FST) in mice has failed to predict antidepressant activity for drugs having beta adrenoreceptor agonist activity and for serotonin uptake inhibitors. We investigated the potential for clonidine to render the FST sensitive to antidepressants by using a behaviorally inactive dose of this agent (0.1 mg/kg). All antidepressants studied (tricyclics, 5-HT uptake inhibitors, iprindole, mianserin, viloxazine, trazodone) showed either activity at lower doses or activity at pr...

  17. Occupational eczema and asthma in a hairdresser caused by hair-bleaching products

    DEFF Research Database (Denmark)

    Hougaard, Majken G; Menné, Torkil; Søsted, Heidi

    2012-01-01

    understood. The specific inhalation challenge test is considered to be the gold standard for diagnosing occupational asthma and rhinitis. However, this test is not always accessible. Therefore, the diagnosis of occupational allergic asthma caused by persulfate salts is made by combining a clinical history......, a diagnosis of asthma, and a positive skin prick test (SPT). Standardized methods for performing SPT with persulfate salts are warranted. A case of a young hairdresser with occupational asthma and hand eczema caused by persulfate salts is presented, and the procedure for performing the SPT with ammonium......Occupational allergic contact eczema and asthma caused by bleaching agents is seen in hairdressers. Bleaching agents contain persulfate salts, which are known to induce immediate reactions such as rhinitis, asthma, contact urticaria, and anaphylaxis. The immunologic mechanism is not, however, fully...

  18. Occupational eczema and asthma in a hairdresser caused by hair-bleaching products.

    Science.gov (United States)

    Hougaard, Majken G; Menné, Torkil; Søsted, Heidi

    2012-01-01

    Occupational allergic contact eczema and asthma caused by bleaching agents is seen in hairdressers. Bleaching agents contain persulfate salts, which are known to induce immediate reactions such as rhinitis, asthma, contact urticaria, and anaphylaxis. The immunologic mechanism is not, however, fully understood. The specific inhalation challenge test is considered to be the gold standard for diagnosing occupational asthma and rhinitis. However, this test is not always accessible. Therefore, the diagnosis of occupational allergic asthma caused by persulfate salts is made by combining a clinical history, a diagnosis of asthma, and a positive skin prick test (SPT). Standardized methods for performing SPT with persulfate salts are warranted. A case of a young hairdresser with occupational asthma and hand eczema caused by persulfate salts is presented, and the procedure for performing the SPT with ammonium persulfate and potassium persulfate is described in detail.

  19. Identifying well-bleached quartz using the different bleaching rates of quartz and feldspar luminescence signals

    DEFF Research Database (Denmark)

    Murray, A.S.; Thomsen, Kristina Jørkov; Masuda, N.;

    2012-01-01

    When dating older sedimentary deposits using quartz, there are no unambiguous methods for identifying the presence of incomplete bleaching. Current statistical analysis of dose distributions depends entirely on the assumption that incomplete bleaching and mixing are the main causes of any excess...... in relative bleaching rates of quartz optically stimulated luminescence (OSL) and feldspar luminescence stimulated at 50 °C by infrared light (IR50) and feldspar luminescence stimulated at 290 °C by infrared light after a stimulation at 50 °C (pIRIR290), and use recently deposited samples to determine...... that the large aliquot data are more likely to be correct. We conclude that a comparison of quartz and feldspar doses provides a useful independent method for identifying well-bleached quartz samples, and that it is unwise to apply statistical models to dose distributions without clear evidence for the physical...

  20. The influence of active vision on the exoskeleton of intelligent agents

    Science.gov (United States)

    Smith, Patrice; Terry, Theodore B.

    2016-04-01

    Chameleonization occurs when a self-learning autonomous mobile system's (SLAMR) active vision scans the surface of which it is perched causing the exoskeleton to changes colors exhibiting a chameleon effect. Intelligent agents having the ability to adapt to their environment and exhibit key survivability characteristics of its environments would largely be due in part to the use of active vision. Active vision would allow the intelligent agent to scan its environment and adapt as needed in order to avoid detection. The SLAMR system would have an exoskeleton, which would change, based on the surface it was perched on; this is known as the "chameleon effect." Not in the common sense of the term, but from the techno-bio inspired meaning as addressed in our previous paper. Active vision, utilizing stereoscopic color sensing functionality would enable the intelligent agent to scan an object within its close proximity, determine the color scheme, and match it; allowing the agent to blend with its environment. Through the use of its' optical capabilities, the SLAMR system would be able to further determine its position, taking into account spatial and temporal correlation and spatial frequency content of neighboring structures further ensuring successful background blending. The complex visual tasks of identifying objects, using edge detection, image filtering, and feature extraction are essential for an intelligent agent to gain additional knowledge about its environmental surroundings.

  1. The application of catalase for the elimination of hydrogen peroxide residues after bleaching of cotton fabrics

    Directory of Open Access Journals (Sweden)

    AMORIM ALEXANDRA M.

    2002-01-01

    Full Text Available Results of dyeing of cotton fabrics with a bifunctional reactive dye were significantly improved when the fabric after bleaching with hydrogen peroxide was treated with catalase for the elimination of hydrogen peroxide residues from the fabrics. Compared to processes with a varying number of washing steps, with and without commercial reducing agents, the consumption of water could be significantly reduced, without altering the final color shade.

  2. HYDROGEN PEROXIDE BLEACHING OF CMP PULP USING MAGNESIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Farhad Zeinaly

    2009-11-01

    Full Text Available Conventional bleaching of hardwood CMP pulp with magnesium hydroxide (Mg(OH2 show significant benefits over bleaching with sodium hydroxide (NaOH under various conditions. Magnesium hydroxide bleaching generate higher optical properties, higher pulp yield and lower effluent COD at the same chemical charge, but the physical properties were found to be similar for both processes. The initial freeness of the bleached pulps and refining value to reach a target freeness (about 350 ml. CSF were more for the Mg(OH2-based process. The residual peroxide of filtrate from the Mg(OH2-based process was very high as compared to conventional bleaching.

  3. Effect of Bleaching on Color Change and Surface Topography of Composite Restorations

    Directory of Open Access Journals (Sweden)

    Gunjan Pruthi

    2010-01-01

    Full Text Available This study was conducted to determine the effect of 15% carbamide peroxide bleaching agent on color change and surface topography of different composite veneering materials (Filtek Z350 (3M ESPE, Esthet X (Dentsply India, and Admira (Voco, Germany. Methods. 30 samples were fabricated for evaluation of color change using CIELAB color system and Gonioreflectometer (GK 311/M, ZEISS. 45 disc-shaped specimens were made for evaluation of surface topography after bleaching (Nupro White Gold; Dentsply using SEM. Statistical analysis. One way ANOVA and Multiple comparison tests were used to analyze the data. Statistical significance was declared if the P value was .05 or less. Results and conclusion. All the specimens showed significant discoloration (ΔE>3.3 after their immersion in solutions representing food and beverages. The total color change after bleaching as compared to baseline color was significant in Filtek Z350 (P=.000 and Esthet X (P=.002, while it was insignificant for Admira (P=.18. Esthet X showed maximum surface roughness followed by Admira and Filtek Z350. Bleaching was effective in reducing the discoloration to a clinically acceptable value in all the three groups (ΔE<3.3.

  4. BLEACHING EUCALYPTUS PULPS WITH SHORT SEQUENCES

    Directory of Open Access Journals (Sweden)

    Flaviana Reis Milagres

    2011-03-01

    Full Text Available Eucalyptus spp kraft pulp, due to its high content of hexenuronic acids, is quite easy to bleach. Therefore, investigations have been made attempting to decrease the number of stages in the bleaching process in order to minimize capital costs. This study focused on the evaluation of short ECF (Elemental Chlorine Free and TCF (Totally Chlorine Free sequences for bleaching oxygen delignified Eucalyptus spp kraft pulp to 90% ISO brightness: PMoDP (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, PMoD/P (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, without washing PMoD(PO (Molybdenum catalyzed acid peroxide, chlorine dioxide and pressurized peroxide, D(EPODP (chlorine dioxide, extraction oxidative with oxygen and peroxide, chlorine dioxide and hydrogen peroxide, PMoQ(PO (Molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide, and XPMoQ(PO (Enzyme, molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide. Uncommon pulp treatments, such as molybdenum catalyzed acid peroxide (PMo and xylanase (X bleaching stages, were used. Among the ECF alternatives, the two-stage PMoD/P sequence proved highly cost-effective without affecting pulp quality in relation to the traditional D(EPODP sequence and produced better quality effluent in relation to the reference. However, a four stage sequence, XPMoQ(PO, was required to achieve full brightness using the TCF technology. This sequence was highly cost-effective although it only produced pulp of acceptable quality.

  5. Coronal microleakage with five different temporary restorative materials following walking bleach technique: An ex-vivo study

    Directory of Open Access Journals (Sweden)

    G. P. V Srikumar

    2012-01-01

    Full Text Available Context: Walking bleach technique uses 30% hydrogen peroxide and sodium perborate, and this paste mixture causes loosening of the coronal temporary restorative materials and thus decreasing its clinical effectiveness and causing irritation to the patients oral tissues. In the present study, sealing ability of hygroscopic coronal temporary restorative materials were compared with the other commonly used temporary restorative materials. Aim: To evaluate the effects of walking bleach material on the marginal sealing ability and coronal microleakage of the hydrophilic temporary restorative materials with that of the other commonly used temporary restorative materials in endodontic practice. Materials and Methods: Seventy-five extracted human maxillary central incisor teeth were prepared chemo-mechanically and obturated with gutta-percha in lateral condensation technique. Surface of each tooth was double coated with cyanoacrylate glue. All the teeth were randomly divided in to five groups. Out of 15 teeth in each group, 10 teeth served as experimental specimens, in which bleaching agent was placed in the pulp chamber and 5 teeth served as control, in which no bleaching agent was placed. The access cavities were restored with temporary restorative materials being tested per each group respectively. The specimens were then immersed in 1% India ink dye and subjected to thermo cycling for 7 days. All the teeth were longitudinally sectioned and observed with stereomicroscope and were graded according to the depth of linear dye penetration. Statistical Analysis Used: Mann-Whitney U test and Kruskal-Wallis test. Results: Hydrophilic temporary restorative materials Cavit G and Coltosol F have shown minimal coronal dye leakage with better sealing ability when exposed to walking bleach paste mixture in the dye penetration tests compared to other commonly used temporary restorative materials. Conclusion: Marginal sealing ability of Cavit G and Coltosol F were

  6. Global warming and recurrent mass bleaching of corals

    Science.gov (United States)

    Hughes, Terry P.; Kerry, James T.; Álvarez-Noriega, Mariana; Álvarez-Romero, Jorge G.; Anderson, Kristen D.; Baird, Andrew H.; Babcock, Russell C.; Beger, Maria; Bellwood, David R.; Berkelmans, Ray; Bridge, Tom C.; Butler, Ian R.; Byrne, Maria; Cantin, Neal E.; Comeau, Steeve; Connolly, Sean R.; Cumming, Graeme S.; Dalton, Steven J.; Diaz-Pulido, Guillermo; Eakin, C. Mark; Figueira, Will F.; Gilmour, James P.; Harrison, Hugo B.; Heron, Scott F.; Hoey, Andrew S.; Hobbs, Jean-Paul A.; Hoogenboom, Mia O.; Kennedy, Emma V.; Kuo, Chao-Yang; Lough, Janice M.; Lowe, Ryan J.; Liu, Gang; McCulloch, Malcolm T.; Malcolm, Hamish A.; McWilliam, Michael J.; Pandolfi, John M.; Pears, Rachel J.; Pratchett, Morgan S.; Schoepf, Verena; Simpson, Tristan; Skirving, William J.; Sommer, Brigitte; Torda, Gergely; Wachenfeld, David R.; Willis, Bette L.; Wilson, Shaun K.

    2017-03-01

    During 2015–2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs.

  7. Multi-Agent System for Managing Human Activities in Space Operations

    Science.gov (United States)

    Schrenkenghost, Debra; Bonasso, R. Peter

    2006-01-01

    In manned space operations today, the astronauts' activity schedules are preplanned and adjusted daily on Earth. We have developed the Distributed Collaboration and Interaction (DCI) multi-agent system to investigate automating aspects of human activity management. The DCI System assists (1) plan generation, (2) human activity tracking, (3) plan revision, and (4) mixed initiative interaction with the plan. We have deployed and evaluated the DCI system at JSC to assist control engineers in managing anomaly handling activities for automated life support systems. DCI operated round the clock for 20 months in the Water Research Facility at JSC. Using this software, we reduced anomaly response time by engineers from up to 10 hours in previous tests to under an hour. Based on this evaluation, we conclude that agent assistance for schedule management has potential to improve astronaut activity awareness and reduce response time in situations where crew are interrupted to handle anomalies.

  8. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    Directory of Open Access Journals (Sweden)

    G. Dishon

    2015-06-01

    Full Text Available Coral reefs occupy only ~0.1% of the oceans habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced significant global declines due to a variety of causes, one of the major being widespread coral bleaching events. During bleaching the coral expels its symbiotic algae losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been extensively investigated, there is no scientific data on historical coral bleaching prior to 1979. In this study, we employ high-resolution femtosecond Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS to demonstrate a distinct biologically-induced decline of boron (B isotopic composition (δ11B as a result of coral bleaching. These findings and methodology offer a new use for a previously developed isotopic proxy to reconstruct paleo-coral bleaching events. Based on a literature review of published δ11B data and our recorded "vital effect" of coral bleaching on the δ11B signal, we also describe at least two possible coral bleaching events since the Last Glacial Maximum. The implementation of this bleaching proxy holds the potential of identifying occurrences of coral bleaching throughout the geological record. A deeper temporal view of coral bleaching will enable scientists to determine if it occurred in the past during times of environmental change and what outcome it may have had on coral population structure.

  9. Targeting and timing promotional activities : An agent-based model for the takeoff of new products

    NARCIS (Netherlands)

    Delre, S. A.; Jager, W.; Bijmolt, T. H. A.; Janssen, M. A.

    2007-01-01

    Many marketing efforts focus on promotional activities that support the launch of new products. Promotional strategies may play a crucial role in the early stages of the product life cycle, and determine to a large extent the diffusion of a new product. This paper proposes an agent-based model to si

  10. Chicken cathelicidin-2-derived peptides with enhanced immunomodulatory and antibacterial activities against biological warfare agents

    NARCIS (Netherlands)

    Molhoek, E.M.; van Dijk, A.; Veldhuizen, E.J.A.; Dijk-Knijnenburg, H.; Mars-Groenendijk, R.H.; Boele, L.C.L.; Kaman, W.E.; Haagsman, H.P.; Bikker, F.J.

    2010-01-01

    Host defence peptides (HDPs) are considered to be excellent candidates for the development of novel therapeutic agents. Recently, it was demonstrated that the peptide C1-15, an N-terminal segment of chicken HDP cathelicidin-2, exhibits potent antibacterial activity while lacking cytotoxicity towards

  11. Influence of chemical agents on the surface area and porosity of active carbon hollow fibers

    Directory of Open Access Journals (Sweden)

    LJILJANA M. KLJAJEVIĆ

    2011-09-01

    Full Text Available Active carbon hollow fibers were prepared from regenerated polysulfone hollow fibers by chemical activation using: disodium hydrogen phosphate 2-hydrate, disodium tetraborate 10-hydrate, hydrogen peroxide, and diammonium hydrogen phosphate. After chemical activation fibers were carbonized in an inert atmosphere. The specific surface area and porosity of obtained carbons were studied by nitrogen adsorption–desorption isotherms at 77 K, while the structures were examined with scanning electron microscopy and X-ray diffraction. The activation process increases these adsorption properties of fibers being more pronounced for active carbon fibers obtained with disodium tetraborate 10-hydrate and hydrogen peroxide as activator. The obtained active hollow carbons are microporous with different pore size distribution. Chemical activation with phosphates produces active carbon material with small surface area but with both mesopores and micropores. X-ray diffraction shows that besides turbostratic structure typical for carbon materials, there are some peaks which indicate some intermediate reaction products when sodium salts were used as activating agent. Based on data from the electrochemical measurements the activity and porosity of the active fibers depend strongly on the oxidizing agent applied.

  12. Changes in bleaching susceptibility among corals subject to ocean warming and recurrent bleaching in Moorea, French Polynesia.

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    Morgan S Pratchett

    Full Text Available BACKGROUND: Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. METHODOLOGY/PRINCIPAL FINDINGS: This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites, during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98% than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. CONCLUSIONS/SIGNIFICANCE: Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species is producing a coral assemblage that is

  13. Coral bleaching response index: a new tool to standardize and compare susceptibility to thermal bleaching.

    Science.gov (United States)

    Swain, Timothy D; Vega-Perkins, Jesse B; Oestreich, William K; Triebold, Conrad; DuBois, Emily; Henss, Jillian; Baird, Andrew; Siple, Margaret; Backman, Vadim; Marcelino, Luisa

    2016-07-01

    As coral bleaching events become more frequent and intense, our ability to predict and mitigate future events depends upon our capacity to interpret patterns within previous episodes. Responses to thermal stress vary among coral species; however the diversity of coral assemblages, environmental conditions, assessment protocols, and severity criteria applied in the global effort to document bleaching patterns creates challenges for the development of a systemic metric of taxon-specific response. Here, we describe and validate a novel framework to standardize bleaching response records and estimate their measurement uncertainties. Taxon-specific bleaching and mortality records (2036) of 374 coral taxa (during 1982-2006) at 316 sites were standardized to average percent tissue area affected and a taxon-specific bleaching response index (taxon-BRI) was calculated by averaging taxon-specific response over all sites where a taxon was present. Differential bleaching among corals was widely variable (mean taxon-BRI = 25.06 ± 18.44%, ±SE). Coral response may differ because holobionts are biologically different (intrinsic factors), they were exposed to different environmental conditions (extrinsic factors), or inconsistencies in reporting (measurement uncertainty). We found that both extrinsic and intrinsic factors have comparable influence within a given site and event (60% and 40% of bleaching response variance of all records explained, respectively). However, when responses of individual taxa are averaged across sites to obtain taxon-BRI, differential response was primarily driven by intrinsic differences among taxa (65% of taxon-BRI variance explained), not conditions across sites (6% explained), nor measurement uncertainty (29% explained). Thus, taxon-BRI is a robust metric of intrinsic susceptibility of coral taxa. Taxon-BRI provides a broadly applicable framework for standardization and error estimation for disparate historical records and collection of novel

  14. Differential nitric oxide synthesis and host apoptotic events correlate with bleaching susceptibility in reef corals

    Science.gov (United States)

    Hawkins, T. D.; Krueger, T.; Becker, S.; Fisher, P. L.; Davy, S. K.

    2014-03-01

    Coral bleaching poses a threat to coral reefs worldwide. As a consequence of the temperature-induced breakdown in coral-dinoflagellate symbiosis, bleaching can have extensive effects on reef communities. However, our understanding of bleaching at a cellular level is limited, and this is particularly true regarding differential susceptibility among coral species. Recent work suggests that bleaching may represent a host innate immune-like response to symbiont dysfunction that involves synthesis of the signalling compound nitric oxide (NO) and the induction of host apoptotic-like cell death. In this study, we examined the activity of apoptosis-regulating enzymes alongside oxidised NO accumulation (a proxy for NO synthesis) in the reef corals Acropora millepora, Montipora digitata, and Pocillopora damicornis during experimental thermal stress. P. damicornis was the most sensitive species, suffering mortality (tissue sloughing) after 5 days at 33 °C but non-lethal bleaching after 9 days at 31.5 °C. A. millepora bleached at 33 °C but remained structurally intact, while M. digitata showed little evidence of bleaching. P. damicornis and A. millepora both exhibited evidence of temperature-induced NO synthesis and, after 5 days of heating, levels of oxidised NO in both species were fivefold higher than in controls maintained at 28.5 °C. These responses preceded bleaching by a number of days and may have occurred before symbiont dysfunction (measured as chlorophyll a degradation and oxidised NO accumulation). In A. millepora, apparent NO synthesis correlated with the induction of host apoptotic-like pathways, while in P. damicornis, the upregulation of apoptotic pathways occurred later. No evidence of elevated NO production or apoptosis was observed in M. digitata at 33 °C and baseline activity of apoptosis-regulating enzymes was negligible in this species. These findings provide important physiological data in the context of the responses of corals to global change and

  15. Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber

    Science.gov (United States)

    Haruyama, Akiko; Kato, Junji; Takemoto, Shinji; Oda, Yutaka; Kawada, Eiji; Takahashi, Toshiyuki; Furusawa, Masahiro

    2016-01-01

    This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching. PMID:27747220

  16. Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber.

    Science.gov (United States)

    Haruyama, Akiko; Kameyama, Atsushi; Kato, Junji; Takemoto, Shinji; Oda, Yutaka; Kawada, Eiji; Takahashi, Toshiyuki; Furusawa, Masahiro

    2016-01-01

    This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching.

  17. Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber

    Directory of Open Access Journals (Sweden)

    Akiko Haruyama

    2016-01-01

    Full Text Available This study evaluated the microtensile bond strength (μTBS of 1-step self-etch adhesives (1-SEAs and 2-step self-etch adhesives (2-SEAs to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2 solution with quartz-tungsten-halogen light-curing unit (Group 1 and 3.5% H2O2-containing titanium dioxide (TiO2 (Pyrenees® activated with 405-nm violet diode laser for 15 min (Group 2. Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens than 1-SEA (where 21 out of 36 failed. These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching.

  18. Effects of 3% sodium ascorbyl phosphate on the hardness and bond strength of human enamel bleached with 10% carbamide peroxide.

    Science.gov (United States)

    da Silva, Ana Paula Brito; Lima, Adriano Fonseca; Cavalcanti, Andrea Nobrega; Marchi, Giselle Maria

    2010-01-01

    For this study, 120 fragments obtained from human third molars were randomly separated into 12 groups (n = 10). Four groups were used for measuring the Knoop hardness number (KHN) of enamel, while the other eight were used for testing the microtensile bond strength (muTBS) of two adhesive systems (Single Bond and Prime & Bond NT). All groups presented statistically similar KHN values. According to bond strength results, bleached enamel without antioxidant application demonstrated the lowest values of all groups. Based on these results, it could be concluded that the bleaching agents used in the present study (with or without sodium ascorbyl phosphate) did not affect human enamel hardness and that sodium ascorbyl phosphate is able to reverse the compromised bonding in bleached human enamel.

  19. The Effects of Short Wave UV Irradiation (254-366nm on Color Values of Recycled and Bleached ONP/OMP Pulps

    Directory of Open Access Journals (Sweden)

    Emrah Peşman

    2011-04-01

    Full Text Available ABSTRACT As it is known, mechanical pulp papers include significant amount of lignin and carbohydrates as well as cellulose. Thus, when these lignin reach papers irradiated with short wave UV light they could not protect their color. In this study, bleaching of ONP/OMG recycled pulps with hydrogen peroxide, sodium percarbonate, sodium dithyonite, sodium borohydride and formamidin sulfunic acid were performed. Then the test papers of these pulps were irradiated with 254-366nm UV light and changes in the ISO Brightness, CIE L*a*b*, yellowness (YI and whiteness (WI values were observed. At the result of study, all bleaching agents were determined as insufficient in the respect of color stability. But if they compared with each other, the two stages sodium percarbonate-sodium borohydride bleaching sequence was gave the best results against to color reversion. Keywords: Old news/old magazine papers (ONP/OMG, Bleaching, Color Stability, UV Irradiation

  20. Ocean acidification causes bleaching and productivity loss in coral reef builders.

    Science.gov (United States)

    Anthony, K R N; Kline, D I; Diaz-Pulido, G; Dove, S; Hoegh-Guldberg, O

    2008-11-11

    Ocean acidification represents a key threat to coral reefs by reducing the calcification rate of framework builders. In addition, acidification is likely to affect the relationship between corals and their symbiotic dinoflagellates and the productivity of this association. However, little is known about how acidification impacts on the physiology of reef builders and how acidification interacts with warming. Here, we report on an 8-week study that compared bleaching, productivity, and calcification responses of crustose coralline algae (CCA) and branching (Acropora) and massive (Porites) coral species in response to acidification and warming. Using a 30-tank experimental system, we manipulated CO(2) levels to simulate doubling and three- to fourfold increases [Intergovernmental Panel on Climate Change (IPCC) projection categories IV and VI] relative to present-day levels under cool and warm scenarios. Results indicated that high CO(2) is a bleaching agent for corals and CCA under high irradiance, acting synergistically with warming to lower thermal bleaching thresholds. We propose that CO(2) induces bleaching via its impact on photoprotective mechanisms of the photosystems. Overall, acidification impacted more strongly on bleaching and productivity than on calcification. Interestingly, the intermediate, warm CO(2) scenario led to a 30% increase in productivity in Acropora, whereas high CO(2) lead to zero productivity in both corals. CCA were most sensitive to acidification, with high CO(2) leading to negative productivity and high rates of net dissolution. Our findings suggest that sensitive reef-building species such as CCA may be pushed beyond their thresholds for growth and survival within the next few decades whereas corals will show delayed and mixed responses.

  1. Enzyme, Antibody, and Photocatalytically Active Nanoscale Scavengers and Sensors for CW and Biological Agents

    Science.gov (United States)

    2008-06-10

    increased the useful life of enzymes in coatings with TiO2 . Selective capture of bacteria by modified coatings: • Antibodies immobilized in...CLASSIFICATION OF: Thin films consisting of photoactive TiO2 and enzyme-functionalized polymer were studied for their activity against chemical agent...simulants. The photochemistry of TiO2 was quantitatively studied for several molecules, including the activation of molecular oxygen which then oxidizes

  2. Effect of In-Office Carbamide Peroxide-Based Tooth Bleaching System on Wear Resistance of Silorane-Based and Methacrylate-Based Dental Composites

    Science.gov (United States)

    Hasani Tabatabaei, Masoumeh; Sheikhzadeh, Sedigheh; Ghasemi Monfared Rad, Hamidreza; Beygi, Ahmad

    2015-01-01

    Objectives: Several studies have assessed the characteristics and properties of silorane-based composites and adhesive systems. Considering the extensive application of tooth-whitening agents, possible deteriorative effects of tooth bleaching agents on these restorative materials must be studied. The aim of this study was to evaluate the effect of an in-office carbamide peroxide-based tooth bleaching agent on the wear resistance of a silorane-based and a conventional microhybrid dimethyl methacrylate-based dental composite with two different application times. Materials and Methods: Thirty cylindrical specimens were made of Z250 and P90 dental composite resins (n=15 for each composite). Samples made of each composite were divided into three groups (n=5) for immersion in an in-office bleaching agent (Opalescence® Quick 45%) for either three or eight hours or saline solution (control). Wear tests were conducted after bleaching using a pin-on disk apparatus under the load of 40N at a constant sliding speed of 0.5 ms−1 for a sliding distance of 300 m. The samples were weighed before and after the wear test. Repeated measures ANOVA was used to statistically analyze the obtained data (α=0.05). Results: There was a significant decrease in the weight of samples after the wear test (P0.05). Conclusion: Bleaching for three or eight hours using 45% carbamide peroxide had no deteriorative effect on the wear resistance of Z250 and P90 composites. PMID:27123014

  3. Improved sensitivity, safety and laboratory turnaround time in the diagnosis of pulmonary tuberculosis by use of bleach sedimentation

    Directory of Open Access Journals (Sweden)

    Ameh James

    2015-05-01

    Full Text Available Background: Inadequate diagnostic processes and human resources in laboratories contribute to a high burden of tuberculosis (TB in low- and middle-income countries. Direct smear microscopy is relied on for TB diagnosis; however, sensitivity rates vary. To improve sensitivity of direct microscopy, the researchers employed several approaches, including sputum digestion and concentration of acid-fast bacilli (AFB, a technique which uses commercial bleach.Objectives: This study compared methods used to diagnose active Mycobacterium tuberculosis infections.Methods: Three sputum specimens were collected from each of 340 participants in Abuja, Nigeria, over two consecutive days. Direct microscopy was performed on all specimens; following microscopy, one specimen from each patient was selected randomly for bleach sedimentation and one for Lowenstein-Jensen culture.Results: Direct microscopy produced 28.8% AFB-positive results, whilst bleach sedimentation resulted in 30.3%. When compared with the cultures, 26.5% were AFB true positive using direct microscopy and 27.1% using bleach sedimentation. Whilst the specificity rate between these two methods was not statistically significant (P = 0.548, the sensitivity rate was significant (P = 0.004.Conclusion: Based on these results, bleach increases the sensitivity of microscopy compared with direct smear and has similar specificity. When diagnosing new cases of pulmonary TB, one bleach-digested smear is as sensitive as three direct smears, reducing waiting times for patients and ensuring the safety of laboratory technicians.

  4. Incorporating adaptive responses into future projections of coral bleaching.

    Science.gov (United States)

    Logan, Cheryl A; Dunne, John P; Eakin, C Mark; Donner, Simon D

    2014-01-01

    Climate warming threatens to increase mass coral bleaching events, and several studies have projected the demise of tropical coral reefs this century. However, recent evidence indicates corals may be able to respond to thermal stress though adaptive processes (e.g., genetic adaptation, acclimatization, and symbiont shuffling). How these mechanisms might influence warming-induced bleaching remains largely unknown. This study compared how different adaptive processes could affect coral bleaching projections. We used the latest bias-corrected global sea surface temperature (SST) output from the NOAA/GFDL Earth System Model 2 (ESM2M) for the preindustrial period through 2100 to project coral bleaching trajectories. Initial results showed that, in the absence of adaptive processes, application of a preindustrial climatology to the NOAA Coral Reef Watch bleaching prediction method overpredicts the present-day bleaching frequency. This suggests that corals may have already responded adaptively to some warming over the industrial period. We then modified the prediction method so that the bleaching threshold either permanently increased in response to thermal history (e.g., simulating directional genetic selection) or temporarily increased for 2-10 years in response to a bleaching event (e.g., simulating symbiont shuffling). A bleaching threshold that changes relative to the preceding 60 years of thermal history reduced the frequency of mass bleaching events by 20-80% compared with the 'no adaptive response' prediction model by 2100, depending on the emissions scenario. When both types of adaptive responses were applied, up to 14% more reef cells avoided high-frequency bleaching by 2100. However, temporary increases in bleaching thresholds alone only delayed the occurrence of high-frequency bleaching by ca. 10 years in all but the lowest emissions scenario. Future research should test the rate and limit of different adaptive responses for coral species across latitudes and

  5. Influência dos agentes clareadores e um refrigerante a base de cola na microdureza do esmalte dental e a ação da saliva na superfície tratada = Influence of bleaching agents and a carbonated soft drink on dental enamel microhardness as well as the artificial saliva effect on the treated surface

    Directory of Open Access Journals (Sweden)

    Araújo, Rodrigo Maximo de

    2006-01-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos de três agentes clareadores e uma bebida carbonatada, à base de cola, sobre a microdureza do esmalte dental, assim como os efeitos da saliva artificial sobre o esmalte tratado com estes agentes. Foram utilizados quarenta dentes incisivos bovinos embutidos em resina acrílica. As amostras foram avaliadas em microdurômetro (Future Tech FM 700 após a divisão em quatro grupos, uma leitura inicial da microdureza serviu como controle do experimento: Grupo 1: peróxido de carbamida a 10% (Whiteness Perfect – FGM; Grupo 2: refrigerante Coca-Cola; Grupo 3: peróxido de carbamida a 37% (Whiteness Super – FGM; Grupo 4: peróxido de hidrogênio a 35% (Whiteness HP – FGM. Os dados foram submetidos aos testes estatísticos ANOVA e Tukey. Conclui-se que os agentes clareadores não diminuíram a microdureza do esmalte; a exposição à Coca-Cola diminuiu significantemente a microdureza do esmalte; o tempo de exposição aos agentes foi significante apenas para a Coca- Cola; o armazenamento em saliva aumentou a microdureza do esmalte exposto ao peróxido de carbamida a 37%; à Coca-Cola e ao peróxido de hidrogênio à 35%

  6. Effect of Activating Agent on the Preparation of Bamboo-Based High Surface Area Activated Carbon by Microwave Heating

    Science.gov (United States)

    Xia, Hongying; Wu, Jian; Srinivasakannan, Chandrasekar; Peng, Jinhui; Zhang, Libo

    2016-06-01

    The present work attempts to convert bamboo into a high surface area activated carbon via microwave heating. Different chemical activating agents such as KOH, NaOH, K2CO3 and Na2CO3 were utilized to identify a most suitable activating agent. Among the activating agents tested KOH was found to generate carbon with the highest porosity and surface area. The effect of KOH/C ratio on the porous nature of the activated carbon has been assessed. An optimal KOH/C ratio of 4 was identified, beyond which the surface area as well as the pore volume were found to decrease. At the optimized KOH/C ratio the surface area and the pore volume were estimated to be 3,441 m2/g and 2.093 ml/g, respectively, with the significant proportion of which being microporous (62.3%). Activated carbon prepared under the optimum conditions was further characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Activated carbons with so high surface area and pore volume are very rarely reported, which could be owed to the nature of the precursor and the optimal conditions of mixture ratio adopted in the present work.

  7. The effect of three different mouthrinses on the surface hardness, gloss and colour change of bleached nano composite resins.

    Science.gov (United States)

    Gurgan, Sevil; Yalcin Cakir, Filiz

    2008-09-01

    This in vitro study evaluated the effects of three mouthrinses (Listerine--alcohol containing, Oral B--alcohol free and Rembrandt Plus--peroxide whitening rinse) on the surface hardness, gloss and colour of a nanofill (Filtek Supreme) and nanohybrid (Simile) composite resin that had been subjected to bleaching treatment. 30 specimens of each material were fabricated and randomly divided into three groups of 10. The hardness, gloss and CIE Lab colour parameters of each specimen were assessed prior to the experiments. Specimens were exposed to the 10% carbamide peroxide bleaching agent (Vivastyle) for 2 hours per day for 14 days. Following the bleaching treatment measurements were repeated. The specimens were then conditioned with mouthrinses for 12 hours which was equivalent in time to 1 year of two minutes daily use. The specimens were measured again for hardness, gloss and colour and data were subjected to the statistical analysis. The result of this study showed no statististical difference between the restorative materials after bleaching and the use of mouthrinses (p > 0.05). Bleaching treatment and the use of mouthrinses af fected the hardness, gloss and colour of both resins. Significant differences were observed with the use of mouthrinses for all parameters (p < 0.05). Rembrandt Plus promoted the greatest changes, followed by Listerine and Oral B.

  8. In vitro activities of antimicrobial agents, alone and in combination, against Acinetobacter baumannii isolated from blood.

    Science.gov (United States)

    Chang, S C; Chen, Y C; Luh, K T; Hsieh, W C

    1995-11-01

    In vitro activities of 15 antimicrobial agents against 90 strains of Acinetobacter baumannii isolated from blood cultures from hospitalized patients were determined using the agar dilution method. Imipenem, ofloxacin, and ciprofloxacin had the best antimicrobial activity with minimum inhibitory concentrations (MIC50s) of 0.25 mu g/ml and MIC90s of 0.5-1 mu g/ml. beta-lactam antibiotics other than imipenem had poor activity, with MIC50s ranging from 8 to 64 mu g/ml and MIC90s from 32 to > or = 256 mu g/ml. The checkerboard titration method was used to study the effects of combination of two antimicrobial agents. Combinations of ceftazidime, aztreonam, imipenem, or ciprofloxacin with amikacin showed either synergistic effects or partial synergistic effects for 40.9%-86.4% of 22 tested strains. The best in vitro activity was observed with the combination of imipenem and amikacin. No antagonistic effects were observed with the combination of imipenem and amikacin. Synergistic effects were confirmed by time-kill curve studies. In conclusion, imipenem, ofloxacin, and ciprofloxacin were the three most active agents against human blood isolates of A. baumannii. The combination of a beta-lactam or ciprofloxacin with amikacin was synergistic for some of the isolates.

  9. Agent-based power sharing scheme for active hybrid power sources

    Science.gov (United States)

    Jiang, Zhenhua

    The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

  10. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    Science.gov (United States)

    Vanhoof, R; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-07-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) were resistant to erythromycin. One strain (1.2%) was completely resistant to tobramycin. The tetracyclines (tetracyline, doxycycline, minocycline) were generally effective, but 8% of the strains were totally resistant to them. Minocycline was the most active. Chloramphenicol, thiamphenicol, and clindamycin had good activity. The bacteriostatic and bactericidal distributions for colistin, nalidixic acid, and metronidazole were broad.

  11. Levels of immunity parameters underpin bleaching and disease susceptibility of reef corals.

    Science.gov (United States)

    Palmer, Caroline V; Bythell, John C; Willis, Bette L

    2010-06-01

    Immunity is a key life history trait that may explain hierarchies in the susceptibility of corals to disease and thermal bleaching, two of the greatest current threats to coral health and the persistence of tropical reefs. Despite their ongoing and rapid global decline, there have been few investigations into the immunity mechanisms of reef-building corals. Variables commonly associated with invertebrate immunity, including the presence of melanin, size of melanin-containing granular cells, and phenoloxidase (PO) activity, as well as concentrations of fluorescent proteins (FPs), were investigated in hard (Scleractinia) and soft (Alcyonacea) corals spanning 10 families from the Great Barrier Reef. Detectable levels of these indicators were present in all corals investigated, although relative investment differed among coral taxa. Overall levels of investment were inversely correlated to thermal bleaching and disease susceptibility. In addition, PO activity, melanin-containing granular cell size, and FP concentration were each found to be significant predictors of susceptibility and thus may play key roles in coral immunity. Correlative evidence that taxonomic (family-level) variation in the levels of these constituent immunity parameters underpins susceptibility to both thermal bleaching and disease indicates that baseline immunity underlies the vulnerability of corals to these two threats. This reinforces the necessity of a holistic approach to understanding bleaching and disease in order to accurately determine the resilience of coral reefs.

  12. A global protocol for monitoring of coral bleaching

    OpenAIRE

    Oliver, J.; Setiasih, N.; Marshall, P.; Hansen, L

    2004-01-01

    Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources.

  13. Coral community response to bleaching on a highly disturbed reef

    OpenAIRE

    Guest, J R; Low, J.; Tun, K.; B. Wilson; Ng, C.; Raingeard, D.; K. E. Ulstrup; Tanzil, J. T. I.; Todd, P.A.; Toh, T. C.; McDougald, D; Chou, L.M.; P. D. Steinberg

    2016-01-01

    While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on:...

  14. Coral community response to bleaching on a highly disturbed reef.

    Science.gov (United States)

    Guest, J R; Low, J; Tun, K; Wilson, B; Ng, C; Raingeard, D; Ulstrup, K E; Tanzil, J T I; Todd, P A; Toh, T C; McDougald, D; Chou, L M; Steinberg, P D

    2016-02-15

    While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

  15. Mass coral bleaching in 2010 in the southern Caribbean.

    Science.gov (United States)

    Alemu I, Jahson Berhane; Clement, Ysharda

    2014-01-01

    Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures) varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching.

  16. Mass coral bleaching in 2010 in the southern Caribbean.

    Directory of Open Access Journals (Sweden)

    Jahson Berhane Alemu I

    Full Text Available Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching.

  17. Salinomycin: a novel anti-cancer agent with known anti-coccidial activities.

    Science.gov (United States)

    Zhou, Shuang; Wang, Fengfei; Wong, Eric T; Fonkem, Ekokobe; Hsieh, Tze-Chen; Wu, Joseph M; Wu, Erxi

    2013-01-01

    Salinomycin, traditionally used as an anti-coccidial drug, has recently been shown to possess anti-cancer and anti-cancer stem cell (CSC) effects, as well as activities to overcome multi-drug resistance based on studies using human cancer cell lines, xenograft mice, and in case reports involving cancer patients in pilot clinical trials. Therefore, salinomycin may be considered as a promising novel anti-cancer agent despite its largely unknown mechanism of action. This review summarizes the pharmacologic effects of salinomycin and presents possible mechanisms by which salinomycin exerts its anti-tumorigenic activities. Recent advances and potential complications that might limit the utilization of salinomycin as an anti-cancer and anti-CSC agent are also presented and discussed.

  18. Decontamination of adsorbed chemical warfare agents on activated carbon using hydrogen peroxide solutions.

    Science.gov (United States)

    Osovsky, Ruth; Kaplan, Doron; Nir, Ido; Rotter, Hadar; Elisha, Shmuel; Columbus, Ishay

    2014-09-16

    Mild treatment with hydrogen peroxide solutions (3-30%) efficiently decomposes adsorbed chemical warfare agents (CWAs) on microporous activated carbons used in protective garments and air filters. Better than 95% decomposition of adsorbed sulfur mustard (HD), sarin, and VX was achieved at ambient temperatures within 1-24 h, depending on the H2O2 concentration. HD was oxidized to the nontoxic HD-sulfoxide. The nerve agents were perhydrolyzed to the respective nontoxic methylphosphonic acids. The relative rapidity of the oxidation and perhydrolysis under these conditions is attributed to the microenvironment of the micropores. Apparently, the reactions are favored due to basic sites on the carbon surface. Our findings suggest a potential environmentally friendly route for decontamination of adsorbed CWAs, using H2O2 without the need of cosolvents or activators.

  19. Multi-agent based controller for islanding operation of active distribution networks with distributed generation

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Wu, Qiuwei; Østergaard, Jacob

    2011-01-01

    are important, and the overall network synchronism must be ensured in the islanded distribution system. In this paper, a multi-agent based controller has been proposed to stabilize the frequency and voltages of an active distribution system after it enters into the islanding operation mode. The modified IEEE 9......-bus system was used to investigate the dynamic and steady state performance of the active distribution system during islanding operation. Case studies have been carried out using the Real-Time Digital Simulator (RTDS) based simulation platform. Case study results show that the proposed multi-agent......The increasing amount of distributed generation (DG) in today’s highly complex restructured power networks gives more options for distribution system operators (DSOs) under contingency conditions. A low voltage distribution network with a large amount of DG can be operated as an islanded system...

  20. Synthesis and evaluation of some surface active agents from long chain fatty amine

    Directory of Open Access Journals (Sweden)

    Eissa, A. M. F.

    2007-12-01

    Full Text Available This study continues our series of synthesis of surface active agents containing heterocyclic moiety. NHeptadecanoyl- 3-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl- acrylamide (4 was used as a new starting material to synthesize propenoxylated nonionic surface active agents having heterocycles such as (thiazole, triazole, benzoxazine, quinazoline, triazine, and oxazine. The structures of the prepared compounds were elucidated by using spectroscopic tools (IR, 1H NMR and Mass spectroscopy. Physical properties such as surface and interfacial tension, cloud point, foaming height, wetting time, emulsification power and critical micelle concentration (CMC were determined. Antimicrobial and biodegradability properties were also screened. It was found that the produced novel groups of nonionic surface active agents have pronounced surface properties and good antimicrobial activities.Este estudio continua nuestra serie sobre la síntesis de agentes surfactantes que contienen grupos heterociclicos. N-Heptadecanoyl-3-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl- acrylamida (4 se usa como nueva materia prima para sintetizar surfactantes noiónico propenoxilado conteniendo herociclos tales como thiazol, triazol, benzoxazina, quinazolina, triazina, y oxazina. Las estructuras de los compuestos preparados se dilucidan mediante herramientas espectroscópicas (IR, 1H NMR and espectroscopía de masas. Se determinan sus propiedades físicas, tensión superficial e interfacial, punto de nube, altura de espuma, poder de emulsificación y concentración micelar critica.También se revisan sus propiedades antimicrobianas y de biodegradabilidad Se encontró que los nuevos compuestos poseían destacadas propiedades superficiales y unas buenas actividades antimicrobianas.

  1. In Vitro Activities of New and Conventional Antifungal Agents against Clinical Scedosporium Isolates

    OpenAIRE

    Meletiadis, Joseph; Meis, Jacques F. G. M.; Mouton, Johan W.; Rodriquez-Tudela, Juan Luis; Donnelly, J. Peter; Verweij, Paul E.

    2002-01-01

    The susceptibilities of 13 clinical isolates of Scedosporium apiospermum and 55 clinical isolates of S. prolificans to new and conventional drugs belonging to three different classes of antifungal agents, the azoles (miconazole, itraconazole, voriconazole, UR-9825, posaconazole), the polyenes (amphotericin B, nystatin and liposomal nystatin), and allylamines (terbinafine), were studied by use of proposed standard M38-P of NCCLS. Low growth-inhibitory antifungal activities were found in vitro ...

  2. Novel Bis-Indole Agents Active Against Multidrug-Resistant Acinetobacter baumannii

    Science.gov (United States)

    Jacobs, Michael R.; Bajaksouzian, Saralee; Good, Caryn E.; Butler, Michelle M.; Williams, John D.; Peet, Norton P.; Bowlin, Terry L.; Endimiani, Andrea; Bonomo, Robert A

    2013-01-01

    The in vitro activity of five novel Microbiotix bis-indole agents (MBXs) against 30 multidrug-resistant (MDR) A. baumannii (including 18 resistant to carbapenems) was evaluated. Overall, MIC90s ranged from 1-8 μg/ml, whereas those for imipenem were > 64 μg/ml. MBX 1196 was the most potent (MIC90 1 μg/ml). MBXs are compounds that are highly effective against MDR A. baumannii. PMID:21146724

  3. Structural Insights into the Dual Activities of the Nerve Agent Degrading Organophosphate Anhydrolase/Prolidase

    Science.gov (United States)

    2009-12-11

    many pesticides used worldwide to protect crops and mammals are OP-based. Several insecticides are synthesized as “thion” (PdS bond) and activated by...substrates and stability of OPAA for decontamination of G- and V-type chemical warfare agents and pesticides . MATERIALS AND METHODS OPAA Purification and...Weir, K. M., Coppin, C. W., Williams, M. R., Selleck, M., Russell, R. J., and Oakeshott, J. G. (2004) Enzymatic bioremediation : From enzyme discovery to

  4. Effect of Additive Agent on the Electrochemical Capacitance of Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    Wang Gui-Xin; Qu Mei-Zhen; Chen Li; Wang Guo-Ping; Zhang Qing-Tang; Yu Zuo-Long

    2004-01-01

    In order to compare the effect of additive agent on the electrochemical capacitance of activated carbon, three additive agents like carbon nanotubes (CNTs), activated carbon fibre (ACF)and acetylene black (AB) were added to activated carbon by ultrasonic dispersion. Two electrodes including 95wt.% activated carbon, 2wt.% additive agent and 3wt.% PTFE binder were prepared.Ecs were assembled in an argon-filled glove box by sandwiching a microporous separator (Celgard 2400) between two electrodes. 1.0 M LiClO4/ethylene carbonate (EC)-diethyl carbonate (DEC) (1:1in vol.) was used as the electrolyte. The performance of the Ecs was tested with constant current charge-discharge model between 0.0 and 3.0V at 298K using a battery-testing instrument under the same conditions.From the Fig. 1, we can know that the specific capacitance decreases with the current density increasing. As far as the three carbon materials, CNTs show better performance than others. At low current density, the specific capacitance of CNTs is adjacent to that of ACF, while higher than that of AB; At high current density, the specific capacitance of CNTs is higher than that of both ACF and AB. What's more, capacity fading of CNTs is smaller than those of both ACF and AB. At 10 mA/cm2 current density, the specific capacitance of CNTs is 1.33 times of that ACF and 1.58 times of that AB, respectively. From the CVs (Fig. 2), the capacitance of three materials is contributed mainly by double-layer, nonfaradically. The performance difference is ascribed to the structure and electrolyte reservoir: CNTs used have a wide diameter range between 20 and 100nm and hollow tube structure, ACF has a narrow diameter range and many micropores, AB are dots and cannot form good conductive net. All the above reasons lead the different electrochemical properties of three additive agents.

  5. SOFT MALLEABLE VESICLES TAILORED FOR ENHANCED DELIVERY OF ACTIVE AGENTS THROUGH THE SKIN: AN UPDATE

    OpenAIRE

    Sandeep Kumar Parihar*, Mithun Bhowmick, Rajeev Kumar and Balkrishna Dubey

    2013-01-01

    Ethosomes are noninvasive delivery carriers that enable drugs to reach the deep skin layers and/or the systemic circulation. These are soft, malleable vesicles tailored for enhanced delivery of active agents. They are composed mainly of phospholipids, high concentration of ethanol and water. The high concentration of ethanol makes the ethosomes unique, as ethanol is known for its disturbance of skin lipid bilayer organization; therefore, when integrated into ...

  6. Effects on gastric mucosa induced by dental bleaching – an experimental study with 6% hydrogen peroxide in rats

    Directory of Open Access Journals (Sweden)

    Anabela Baptista PAULA

    2015-10-01

    Full Text Available The value of aesthetic dentistry has precipitated several developments in the investigation of dental materials related to this field. The free marketing of these products is a problem and it is subject to various interpretations regarding its legality. There are several techniques for tooth whitening, the most used one being the external bleaching. It is the later version of such technique that poses the greatest danger of ingesting the product. The present study analysed the systemic effect of these products when they are swallowed.Objective This experimental study aimed to observe the effects of a tooth whitening product, whose active agent is 6% hydrogen peroxide, on the gastric mucosa of healthy and non-tumour gastric pathology animals.Material and Methods Fifty Wistar-Han rats were used and then distributed into 5 groups, one for control and four test groups in which the bleaching product was administered in animals with and without non-tumour gastric pathology (induced by the administration of 1 sample of 50% ethanol and 5% of drinking water during 6 days at different times of study by gavage. There was a decrease in body weight in animals of groups handled during the study period, which was most pronounced in IV and VA groups. Changes in spleen weight relative to body weight revealed no statistically significant changes. An analysis of the frequency was performed on the results of macroscopic observation of the gastric mucosa.Results The gastric mucosa revealed lesions in all manipulated groups, being more frequent in groups III and IV. It appears that there is a synergism when using hydrogen peroxide and 50% ethanol in the same group.Conclusion Therefore, it seems that there are some signs of toxicity 3 to 4 days after administration of 6% hydrogen peroxide. The prescription of these therapies must be controlled by the clinician and the risks must be minimized.

  7. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    OpenAIRE

    G. Dishon; Fisch, J; Horn, I.; K Kaczmarek; Bijma, J.; Gruber, D.F.; O. Nir; Y. Popovich; D. Tchernov

    2015-01-01

    Coral reefs occupy only ~0.1% of the oceans habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced significant global declines due to a variety of causes, one of the major being widespread coral bleaching events. During bleaching the coral expels its symbiotic algae losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events hav...

  8. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    Science.gov (United States)

    Dishon, G.; Fisch, J.; Horn, I.; Kaczmarek, K.; Bijma, J.; Gruber, D. F.; Nir, O.; Popovich, Y.; Tchernov, D.

    2015-10-01

    Coral reefs occupy only ~ 0.1 percent of the ocean's habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced a significant global decline due to a variety of causes, one of the major causes being widespread coral bleaching events. During bleaching, the coral expels its symbiotic algae, thereby losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been extensively investigated, there is no scientific data on historical coral bleaching prior to 1979. In this study, we employ high-resolution femtosecond Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) to demonstrate a distinct biologically induced decline of boron (B) isotopic composition (δ11B) as a result of coral bleaching. These findings and methodology offer a new use for a previously developed isotopic proxy to reconstruct paleo-coral bleaching events. Based on a literature review of published δ11B data and our recorded vital effect of coral bleaching on the δ11B signal, we also describe at least two possible coral bleaching events since the Last Glacial Maximum. The implementation of this bleaching proxy holds the potential of identifying occurrences of coral bleaching throughout the geological record. A deeper temporal view of coral bleaching will enable scientists to determine if it occurred in the past during times of environmental change and what outcome it may have had on coral population structure. Understanding the frequency of bleaching events is also critical for determining the relationship between natural and anthropogenic causes of these events.

  9. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    OpenAIRE

    G. Dishon; Fisch, J; Horn, I.; K Kaczmarek; Bijma, J.; Gruber, D.F.; O. Nir; Y. Popovich; D. Tchernov

    2015-01-01

    Coral reefs occupy only ~ 0.1 percent of the ocean's habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced a significant global decline due to a variety of causes, one of the major causes being widespread coral bleaching events. During bleaching, the coral expels its symbiotic algae, thereby losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been ex...

  10. Argilas bentoníticas da península de Santa Elena, Equador: pilarização, ativação ácida e seu uso como descolorante de óleo de soja Bentonitic clays of Santa Elena península, Ecuador: al-pilarization, acid-activation and its use in the bleaching of soybean oil

    Directory of Open Access Journals (Sweden)

    Ana M. Morales-Carrera

    2009-01-01

    Full Text Available Two samples of calcic bentonite of the Santa Elena Peninsula, Ecuador, were pillared with Al13 ions in the ratio of 10, 15 and 20 meq of Al g-1 of clay, calcinated at 573, 723 and 873 ºK and acid activated with 4, 6 and 8 mol L-1 H2SO4. Analyses by X-ray diffraction, X-ray fluorescence, differential and gravimetric thermal, density, surface area and porosity, were applied in order to study the modifications occurred in the crystalline structure of the montmorillonite. The 8 mol L-1 H2SO4 acid-activated 15 meq of Al g-1 of clay at 573 ºK Al-pillared samples indicated the best results in the bleaching of the soybean oil measured by UV-visible spectrophotometer.

  11. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

    Directory of Open Access Journals (Sweden)

    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  12. Design, synthesis and pharmacological evaluation of omeprazole-like agents with anti-inflammatory activity.

    Science.gov (United States)

    El-Nezhawy, Ahmed O H; Biuomy, Ayman R; Hassan, Fatma S; Ismaiel, Ayman K; Omar, Hany A

    2013-04-01

    A new series of novel benzimidazole derivatives containing substituted pyrid-2-yl moiety and polyhydroxy sugar conjugated to the N-benzimidazole moiety has been synthesized and evaluated as orally bioavailable anti-inflammatory agents with anti-ulcerogenic activity. The anti-inflammatory and anti-ulcerogenic activities of these compounds were compared to diclofenac and omeprazole, respectively. In carrageenan-induced paw oedema assay, 2-methyl-N-((3,4-dimethoxypyridin-2-yl)methyl)-1H-benzimidazol-5-amine (12d) and 1-(1,2,3,5-tetrahydroxy-α-D-mannofuranose)-5-(((3,4-dimethoxypyridin-2yl)methyl)amino)-2-methyl-1H-benzimidazole (15d) displayed dose-dependent anti-inflammatory activities by decreasing the inflammation by 62% and 72%, respectively which is comparable to that of diclofenac (73%). In contrast to diclofenac, the anti-inflammatory activity of these compounds was not only free from any side effects on the gastric mucosa but also showed significant anti-ulcerogenic activity in rat pyloric ligation and ethanol-induced gastric ulcer models similar to that of omeprazole. Together, these findings suggest that 12d and 15d are potent anti-inflammatory agents with concurrent anti-ulcerogenic activity and support its clinical promise as a component of therapeutic strategies for inflammation, for which the gastric side effects are always a major limitation.

  13. Hormetic Effect of Berberine Attenuates the Anticancer Activity of Chemotherapeutic Agents.

    Science.gov (United States)

    Bao, Jiaolin; Huang, Borong; Zou, Lidi; Chen, Shenghui; Zhang, Chao; Zhang, Yulin; Chen, Meiwan; Wan, Jian-Bo; Su, Huanxing; Wang, Yitao; He, Chengwei

    2015-01-01

    Hormesis is a phenomenon of biphasic dose response characterized by exhibiting stimulatory or beneficial effects at low doses and inhibitory or toxic effects at high doses. Increasing numbers of chemicals of various types have been shown to induce apparent hormetic effect on cancer cells. However, the underlying significance and mechanisms remain to be elucidated. Berberine, one of the major active components of Rhizoma coptidis, has been manifested with notable anticancer activities. This study aims to investigate the hormetic effect of berberine and its influence on the anticancer activities of chemotherapeutic agents. Our results demonstrated that berberine at low dose range (1.25 ~ 5 μM) promoted cell proliferation to 112% ~170% of the untreated control in various cancer cells, while berberine at high dose rage (10 ~ 80 μM) inhibited cell proliferation. Further, we observed that co-treatment with low dose berberine could significantly attenuate the anticancer activity of chemotherapeutic agents, including fluorouracil (5-FU), camptothecin (CPT), and paclitaxel (TAX). The hormetic effect and thereby the attenuated anticancer activity of chemotherapeutic drugs by berberine may attributable to the activated protective stress response in cancer cells triggered by berberine, as evidenced by up-regulated MAPK/ERK1/2 and PI3K/AKT signaling pathways. These results provided important information to understand the potential side effects of hormesis, and suggested cautious application of natural compounds and relevant herbs in adjuvant treatment of cancer.

  14. Hormetic Effect of Berberine Attenuates the Anticancer Activity of Chemotherapeutic Agents.

    Directory of Open Access Journals (Sweden)

    Jiaolin Bao

    Full Text Available Hormesis is a phenomenon of biphasic dose response characterized by exhibiting stimulatory or beneficial effects at low doses and inhibitory or toxic effects at high doses. Increasing numbers of chemicals of various types have been shown to induce apparent hormetic effect on cancer cells. However, the underlying significance and mechanisms remain to be elucidated. Berberine, one of the major active components of Rhizoma coptidis, has been manifested with notable anticancer activities. This study aims to investigate the hormetic effect of berberine and its influence on the anticancer activities of chemotherapeutic agents. Our results demonstrated that berberine at low dose range (1.25 ~ 5 μM promoted cell proliferation to 112% ~170% of the untreated control in various cancer cells, while berberine at high dose rage (10 ~ 80 μM inhibited cell proliferation. Further, we observed that co-treatment with low dose berberine could significantly attenuate the anticancer activity of chemotherapeutic agents, including fluorouracil (5-FU, camptothecin (CPT, and paclitaxel (TAX. The hormetic effect and thereby the attenuated anticancer activity of chemotherapeutic drugs by berberine may attributable to the activated protective stress response in cancer cells triggered by berberine, as evidenced by up-regulated MAPK/ERK1/2 and PI3K/AKT signaling pathways. These results provided important information to understand the potential side effects of hormesis, and suggested cautious application of natural compounds and relevant herbs in adjuvant treatment of cancer.

  15. Design, diversity-oriented synthesis and structure activity relationship studies of quinolinyl heterocycles as antimycobacterial agents.

    Science.gov (United States)

    Rachakonda, Venkatesham; Alla, Manjula; Kotipalli, Sudha Sravanti; Ummani, Ramesh

    2013-01-01

    The current study reports design and diversity oriented synthesis of novel bis heterocycles with a common 2-methyl, C-4 unsubstituted quinoline moiety as the central key heterocycle. Employing reagent based skeletal diversity approach; a facile synthesis of bis heterocycles with different heterocyclic rings at C-3 position of the quinoline moiety has been accomplished. A broad range of heterocyclic frameworks thus obtained were evaluated for their antimycobacterial activity. The active scaffolds were further explored by a parallel library generation in order to establish SAR. Further, low cytotoxicity against A549 cell line enhances the potential of the synthesized molecules as promising antimycobacterial agents.

  16. Environmental factors affect the activity of biocontrol agents against ochratoxigenic Aspergillus carbonarius on wine grape.

    Science.gov (United States)

    De Curtis, F; de Felice, D V; Ianiri, G; De Cicco, V; Castoria, R

    2012-09-17

    The influence of temperature and relative humidity (RH) on the activity of three biocontrol agents-the yeast Metschnikowia pulcherrima LS16 and two strains of the yeast-like fungus Aureobasidium pullulans LS30 and AU34-2-against infection by A. carbonarius and ochratoxin A (OTA) accumulation in wine grape berries was investigated in lab-scale experiments. The presence of wounds on grape skin dramatically favored infection of berries by A. carbonarius strain A1102, since unwounded berries showed very low levels of infection at all conditions of RH and temperature tested. Artificially wounded berries pre-treated with the biocontrol agents were inoculated with the ochratoxigenic A. carbonarius strain A1102 and were incubated for 5 days at two levels of RH (60% and 100%) and three different temperatures (20, 25 and 30 °C). The three biocontrol agents were able to prevent infections at 60% RH and 20 °C. At 60% RH and 25 °C only strain AU34-2 achieved some protection on day 5, whereas at 30 °C a limited biocontrol efficacy was evident only up to day 2. At 100% RH, LS16, LS30 and AU34-2 showed effective protection of grape berries at 20 °C until the 5th day of incubation. The three biocontrol agents achieved significant protection at higher temperatures only until the 2nd day after the beginning of the experiment: all three strains at 25 °C, and only strain LS16 at 30 °C. After 5 days, the three biocontrol agents were able to significantly reduce the level of OTA in berries at all the conditions tested. This occurred even when protection from infection was not significant, except at 30 °C and 100% of RH for all the three strains, and at 25 °C and 100% of RH for strain LS16. The biocontrol agents displayed a higher rate of colonization on grape berries at 20 and 25 °C than at 30 °C. The higher value of RH (100%) appeared to increase the rate of colonization, in particular at 20 and 25 °C. Taken together, our results emphasize the significant influence of

  17. The application of click chemistry in the synthesis of agents with anticancer activity.

    Science.gov (United States)

    Ma, Nan; Wang, Ying; Zhao, Bing-Xin; Ye, Wen-Cai; Jiang, Sheng

    2015-01-01

    The copper(I)-catalyzed 1,3-dipolar cycloaddition between alkynes and azides (click chemistry) to form 1,2,3-triazoles is the most popular reaction due to its reliability, specificity, and biocompatibility. This reaction has the potential to shorten procedures, and render more efficient lead identification and optimization procedures in medicinal chemistry, which is a powerful modular synthetic approach toward the assembly of new molecular entities and has been applied in anticancer drugs discovery increasingly. The present review focuses mainly on the applications of this reaction in the field of synthesis of agents with anticancer activity, which are divided into four groups: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, and antimicrotubule agents.

  18. Bleach Plant Capital Reduction with Rapid DO Bleaching and Simplified (D/E/D) Stages

    Energy Technology Data Exchange (ETDEWEB)

    T. J. McDonough; C. E. Courchene; J-C. Baromes

    2000-08-01

    The objective of this work was to demonstrate the capabilities of a bleaching sequence that combined a short retention time initial chlorine dioxide stage, referred to as rapid D0, (D0R), with simplified bleaching stages, (D1/E/D2), that required only one final bleach washer. The test sequence DR(EPO)(D/E/D/) was compared to a control sequence, D(EPO)D, for both hardwood and softwood pulps. The capabilities of the DR(EPO)(D/E/D) sequence were successfully demonstrated. An existing three- or four-stage bleach plan can be converted to the more powerful DR(EPO)(D/E/D) sequence without the major capital cost of additional washers. The results from this study showed that the DR(EPO)(D/E/D) sequence can reach 85 brightness on SW with 2.8% total C1O2, while the control sequence, D(EPO)D, required 3.9% C1O2. There was a corresponding decrease in AOX for the test sequence. The strength of pulp bleached in the test sequence was similar to or slightly higher than the control. For the HW pu lp, the test sequence reached 88 brightness with 2.2% C1O2 compared to 3.3% C1O2 for the control. There was a corresponding decrease in AOX generation with the lower chemical requirements. The final viscosity and pulp strength for the test sequence on HW was significantly higher than the corresponding values for the control sequence.

  19. Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook

    Science.gov (United States)

    Baker, Andrew C.; Glynn, Peter W.; Riegl, Bernhard

    2008-12-01

    regenerating and recovering coral reefs have originated from broadcast spawning taxa with a potential for asexual growth, relatively long distance dispersal, successful settlement, rapid growth and a capacity for framework construction. Whether or not affected reefs can continue to function as before will depend on: (1) how much coral cover is lost, and which species are locally extirpated; (2) the ability of remnant and recovering coral communities to adapt or acclimatize to higher temperatures and other climatic factors such as reductions in aragonite saturation state; (3) the changing balance between reef accumulation and bioerosion; and (4) our ability to maintain ecosystem resilience by restoring healthy levels of herbivory, macroalgal cover, and coral recruitment. Bleaching disturbances are likely to become a chronic stress in many reef areas in the coming decades, and coral communities, if they cannot recover quickly enough, are likely to be reduced to their most hardy or adaptable constituents. Some degraded reefs may already be approaching this ecological asymptote, although to date there have not been any global extinctions of individual coral species as a result of bleaching events. Since human populations inhabiting tropical coastal areas derive great value from coral reefs, the degradation of these ecosystems as a result of coral bleaching and its associated impacts is of considerable societal, as well as biological concern. Coral reef conservation strategies now recognize climate change as a principal threat, and are engaged in efforts to allocate conservation activity according to geographic-, taxonomic-, and habitat-specific priorities to maximize coral reef survival. Efforts to forecast and monitor bleaching, involving both remote sensed observations and coupled ocean-atmosphere climate models, are also underway. In addition to these efforts, attempts to minimize and mitigate bleaching impacts on reefs are immediately required. If significant reductions in

  20. HURON (HUman and Robotic Optimization Network) Multi-Agent Temporal Activity Planner/Scheduler

    Science.gov (United States)

    Hua, Hook; Mrozinski, Joseph J.; Elfes, Alberto; Adumitroaie, Virgil; Shelton, Kacie E.; Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2012-01-01

    HURON solves the problem of how to optimize a plan and schedule for assigning multiple agents to a temporal sequence of actions (e.g., science tasks). Developed as a generic planning and scheduling tool, HURON has been used to optimize space mission surface operations. The tool has also been used to analyze lunar architectures for a variety of surface operational scenarios in order to maximize return on investment and productivity. These scenarios include numerous science activities performed by a diverse set of agents: humans, teleoperated rovers, and autonomous rovers. Once given a set of agents, activities, resources, resource constraints, temporal constraints, and de pendencies, HURON computes an optimal schedule that meets a specified goal (e.g., maximum productivity or minimum time), subject to the constraints. HURON performs planning and scheduling optimization as a graph search in state-space with forward progression. Each node in the graph contains a state instance. Starting with the initial node, a graph is automatically constructed with new successive nodes of each new state to explore. The optimization uses a set of pre-conditions and post-conditions to create the children states. The Python language was adopted to not only enable more agile development, but to also allow the domain experts to easily define their optimization models. A graphical user interface was also developed to facilitate real-time search information feedback and interaction by the operator in the search optimization process. The HURON package has many potential uses in the fields of Operations Research and Management Science where this technology applies to many commercial domains requiring optimization to reduce costs. For example, optimizing a fleet of transportation truck routes, aircraft flight scheduling, and other route-planning scenarios involving multiple agent task optimization would all benefit by using HURON.

  1. Investigating Motivations for Women's Skin Bleaching in Tanzania

    Science.gov (United States)

    Lewis, Kelly M.; Robkin, Navit; Gaska, Karie; Njoki, Lillian Carol

    2011-01-01

    Why do many African women continue to use damaging skin-bleaching cosmetics that contain dangerous chemicals (e.g., mercury) that may increase their rates of infertility, skin cancer, and serious skin/brain/kidney disease? To address this question, our study investigated motivations driving the preservation of skin-bleaching practices in Tanzania.…

  2. The Bleaching Syndrome: The Role of Educational Intervention

    Science.gov (United States)

    Hall, Ronald E.

    2016-01-01

    Per the Bleaching Syndrome, people of color, including African, Asian, and Latino Americans, are both victims and perpetrators of color discrimination. The Bleaching Syndrome encompasses perceptual, psychological, and behavioral sectors that affect students' schooling experiences. Education professionals, including teachers, administrators, and…

  3. The effects of habitat on coral bleaching responses in Kenya.

    Science.gov (United States)

    Grimsditch, Gabriel; Mwaura, Jelvas M; Kilonzo, Joseph; Amiyo, Nassir

    2010-06-01

    This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa and Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching incidence was monitored for the whole coral community, while zooxanthellae densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea, and Porites cylindrica) during a non-bleaching year (2006) and a year of mild-bleaching (2007). Differences in bleaching responses between habitats were observed, with shallower sites Kanamai and Vipingo exhibiting lower bleaching incidence than deeper sites Nyali and Mombasa. These shallower lagoons display more fluctuating thermal and light environments than the deeper sites, suggesting that corals in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily basis and have become more resistant to bleaching stress. In deeper sites that did exhibit higher bleaching (Mombasa and Nyali), it was found that coral recovery occurred more quickly in the protected area than in the non-protected area.

  4. Genotoxic potential of 10% and 16% Carbamide Peroxide in dental bleaching

    Directory of Open Access Journals (Sweden)

    Aline Ferreira de ALMEIDA

    2015-01-01

    Full Text Available Dental bleaching has become one of the most frequently requested esthetic treatments in dental offices. Despite the high clinical success observed with this procedure, some adverse effects have been reported, including a potential for developing premalignant lesions, root resorption and tooth sensitivity, especially when misused. The aim of this study was to evaluate the genotoxic response using a micronucleus (MN assay, after the application of two concentrations of carbamide peroxide. Thirty-seven patients were divided into two groups and randomly received either a 10% carbamide peroxide (CP (19 or a 16% carbamide peroxide (18 concentration for 21 days in individual dental trays. Gingival margin cells were collected immediately before the first use (baseline, and then 15 and 45 days after baseline. The cells were placed on a histological slide, stained by the Feulgen technique, and evaluated by an experienced blinded examiner. One thousand cells per slide were counted, and the MN rate was determined. The two groups were analyzed by the Wilcoxon rank-sum test and the Kruskal-Wallis equality-of-populations rank test. A slight increase in MN was observed for both groups, in comparison with the baseline, at 15 days. However, no difference was observed between the two groups (10% and 16%, at either 15 or 45 days (p = 0.90. When bleaching is not prolonged or not performed very frequently, bleaching agents containing carbamide peroxide alone will not cause mutagenic stress on gingival epithelial cells.

  5. Genotoxic potential of 10% and 16% carbamide peroxide in dental bleaching.

    Science.gov (United States)

    Almeida, Aline Ferreira de; Torre, Eliana do Nascimento; Selayaran, Maicon Dos Santos; Leite, Fábio Renato Manzolli; Demarco, Flávio Fernando; Loguercio, Alessandro Dourado; Etges, Adriana

    2015-01-01

    Dental bleaching has become one of the most frequently requested esthetic treatments in dental offices. Despite the high clinical success observed with this procedure, some adverse effects have been reported, including a potential for developing premalignant lesions, root resorption and tooth sensitivity, especially when misused. The aim of this study was to evaluate the genotoxic response using a micronucleus (MN) assay, after the application of two concentrations of carbamide peroxide. Thirty-seven patients were divided into two groups and randomly received either a 10% carbamide peroxide (CP) (19) or a 16% carbamide peroxide (18) concentration for 21 days in individual dental trays. Gingival margin cells were collected immediately before the first use (baseline), and then 15 and 45 days after baseline. The cells were placed on a histological slide, stained by the Feulgen technique, and evaluated by an experienced blinded examiner. One thousand cells per slide were counted, and the MN rate was determined. The two groups were analyzed by the Wilcoxon rank-sum test and the Kruskal-Wallis equality-of-populations rank test. A slight increase in MN was observed for both groups, in comparison with the baseline, at 15 days. However, no difference was observed between the two groups (10% and 16%), at either 15 or 45 days (p = 0.90). When bleaching is not prolonged or not performed very frequently, bleaching agents containing carbamide peroxide alone will not cause mutagenic stress on gingival epithelial cells.

  6. Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.

    Directory of Open Access Journals (Sweden)

    Stephen J Levas

    Full Text Available Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13C of the skeletal, δ(13C, and δ(15N of the animal host and endosymbiont fractions. Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic

  7. Inactivation of staphylococcal virulence factors using a light-activated antimicrobial agent

    Science.gov (United States)

    2009-01-01

    Background One of the limitations of antibiotic therapy is that even after successful killing of the infecting microorganism, virulence factors may still be present and cause significant damage to the host. Light-activated antimicrobials show potential for the treatment of topical infections; therefore if these agents can also inactivate microbial virulence factors, this would represent an advantage over conventional antibiotic therapy. Staphylococcus aureus produces a wide range of virulence factors that contribute to its success as a pathogen by facilitating colonisation and destruction of host tissues. Results In this study, the ability of the light-activated antimicrobial agent methylene blue in combination with laser light of 665 nm to inactivate staphylococcal virulence factors was assessed. A number of proteinaceous virulence factors were exposed to laser light in the presence of methylene blue and their biological activities re-determined. The activities of V8 protease, α-haemolysin and sphingomyelinase were shown to be inhibited in a dose-dependent manner by exposure to laser light in the presence of methylene blue. Conclusion These results suggest that photodynamic therapy could reduce the harmful impact of preformed virulence factors on the host. PMID:19804627

  8. Evaluation of antibacterial activity of N-phosphonium chitosan as a novel polymeric antibacterial agent.

    Science.gov (United States)

    Guo, Aijie; Wang, Feihu; Lin, Wentao; Xu, Xiaofen; Tang, Tingting; Shen, Yuanyuan; Guo, Shengrong

    2014-06-01

    N-phosphonium chitosans (NPCSs) with different degrees of substitution (3%, 13% and 21%) were synthesized and evaluated as novel polymeric antibacterial agents. Their antibacterial activities compared with hydroxypropyltrimethyl ammonium chloride chitosan (HACC), parent chitosan and (5-carboxypentyl) triphenylphosphonium bromide (CTPB) were tested against Escherichia coli and two strains of drug-resistance Staphylococcus aureus by minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and biofilm prevention assays. The results show that the NPCS with 3% or 13% substitution has lower MIC and MBC values and stronger ability to inhibit biofilm formation of all the three bacteria than HACC, chitosan and CTPB. In addition, the antibacterial activity of NPCSs increases with their substitution decreasing from 21% to 3%. Overall, the antibacterial activity of NPCS with 3% or 13% substitution is better than that of NPCS with 21% substitution, HACC with 22% substitution, chitosan and CTPB. It can be considered that NPCS with appropriate degree of substitution has favorable antibacterial activity and is a potential polymeric antibacterial agent.

  9. Inactivation of staphylococcal virulence factors using a light-activated antimicrobial agent

    Directory of Open Access Journals (Sweden)

    Wilson Michael

    2009-10-01

    Full Text Available Abstract Background One of the limitations of antibiotic therapy is that even after successful killing of the infecting microorganism, virulence factors may still be present and cause significant damage to the host. Light-activated antimicrobials show potential for the treatment of topical infections; therefore if these agents can also inactivate microbial virulence factors, this would represent an advantage over conventional antibiotic therapy. Staphylococcus aureus produces a wide range of virulence factors that contribute to its success as a pathogen by facilitating colonisation and destruction of host tissues. Results In this study, the ability of the light-activated antimicrobial agent methylene blue in combination with laser light of 665 nm to inactivate staphylococcal virulence factors was assessed. A number of proteinaceous virulence factors were exposed to laser light in the presence of methylene blue and their biological activities re-determined. The activities of V8 protease, α-haemolysin and sphingomyelinase were shown to be inhibited in a dose-dependent manner by exposure to laser light in the presence of methylene blue. Conclusion These results suggest that photodynamic therapy could reduce the harmful impact of preformed virulence factors on the host.

  10. Effect of the Purple Corn Beverage “Chicha Morada” in Composite Resin during Dental Bleaching

    Science.gov (United States)

    Acuña, Eric Dario; Delgado-Cotrina, Leyla; Rumiche, Francisco Aurelio

    2016-01-01

    During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada), green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n = 5): purple corn (P), purple corn + bleaching (PB), green tea (T), green tea + bleaching (TB), distilled water (W), and distilled water + bleaching (WB). In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p 3.3). PMID:27034897

  11. Effect of a Combined Bleaching Regimen on the Microhardness of a Sealed Methacrylate-based and a Silorane-based Composite

    Directory of Open Access Journals (Sweden)

    Shafiei F.

    2013-09-01

    Full Text Available Statement of Problem: The use of tooth bleaching agents has been very popular treat-ment in dentistry. The bleaching agents have an inherent potential to impair surface properties of existing composite resin restorations. Purpose: This study evaluated the effect of a combined bleaching regimen on the surface microhardness of a Silorane-based and a sealed methacrylate-based composite. Materials and Method: Forty-five specimens of methacrylate-based composite (Ice and 18 specimens of Silorane composite (Filtek Silorane, 3M ESPE; USA were prepared and randomly divided into 5 (1-5 and 2 (6-7 groups (n=9, respectively. After 8-week aging, groups 1 and 6 were remained with no treatment. In groups 2, 4 and 5, the specimens were covered by a surface sealant and light cured. In groups 3, 4, 5 and 7, the specimens were bleached with hydrogen peroxide 40% and then carbamide peroxide 20% for seven days. In group 5, after bleaching, the sealant was removed by polishing. Surface microhardness was measured and the data were analyzed using one-way ANOVA and Tukey tests (α=0.05. Results: The microhardness values of groups 2 to 4 were significantly lower than that of group1 (p 0.05. Conclusion: The combined bleaching regimen used in this study had a substantial negative effect on methacrylate and sealed methacrylate composites but not on Silorane composite. Polishing following the bleaching on the sealed composite yielded a hardness value similar to that of unsealed methacrylate composite (control.

  12. The effect of bleaching on toothbrush abrasion of resin composites

    Directory of Open Access Journals (Sweden)

    Hila Hajizadeh

    2013-01-01

    Full Text Available Aim: This experimental study was designed to focus on the effects of bleaching on toothbrush abrasion in three types of composites with different filler size. Materials and Methods: Forty eight disks were prepared from three types of composite and divided into 6 groups. In the first three groups the abrasion test was done. The remaining groups were bleached and the abrasion test was performed. The weight of the samples before and after abrasion was measured. Statistical analysis was done with one-way ANOVA and Duncan test. Results: There was a significant difference in abrasion of composites with different filler size (P < 0.05. The most amount of abrasion was observed in Z100 after being bleached. An increase in abrasion was noticed in all three types of tested composite after bleaching. Conclusion: According to the findings, it is suggested to use a nano filled resin composite for restoration if the bleaching treatment is required.

  13. In vitro activities of five fluoroquinolone compounds against strains of Streptococcus pneumoniae with resistance to other antimicrobial agents.

    OpenAIRE

    Barry, A. L.; Fuchs, P C; Brown, S. D.

    1996-01-01

    Ciprofloxacin, clinafloxacin, PD 131628, sparfloxacin, and trovafloxacin were tested against 236 strains of Streptococcus pneumoniae, most of which were resistant to other agents. Resistance to multiple antibiotics did not affect the organism's susceptibility to the fluoroquinolones. The fluoroquinolones with in vitro antipneumococcal activity might be particularly useful against strains that are resistant to the more traditional therapeutic agents.

  14. [Effects of nootropic agents on visual functions and lacrimal antioxidative activity in patients with primary open-angle glaucoma].

    Science.gov (United States)

    Davydova, N G; Kuznetsova, T P; Borisova, S A; Abdulkadyrova, M Zh

    2006-01-01

    The paper presents the results of an investigation of the effect of the nootropic agents pantogam and nooclerine on visual functions in patients with primary open-angle glaucoma. These agents have been found to have a beneficial effect on the functional activity of the retina and optic nerve, light sensitivity, hemo- and hydrodynamics of the eye.

  15. Pulpal inflammation after vital tooth bleaching with 38% hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Ardiny Andriani

    2012-06-01

    Full Text Available Background: In-office vital tooth bleaching is a treatment to remove tooth stains. Tooth sensitivity is one of side effect commonly complained by patients receiving this treatment. Purpose: The aim of this study was to examine histological inflammatory cells infiltration of dental pulp after application of 38% H2O2 as a vital tooth bleaching agent. Methods: Under informed consent, a total of 15 premolars from 8 healthy subjects scheduled for orthodontic extraction were used in this study. Thirty eight percent H2O2 was applied on the buccal surface of the treated group. The treated teeth were extracted after 1 hour, 5, 8, and 15 days. All specimens were embedded in paraffin wax, sectioned serially and stained with Hematoxyllin Eosin. Histological specimens were then observed under a light microscope. Results: All treated groups showed a slight disorganization of odontoblasts layer and slight inflammation in the pulp tissue adjacent to the 38% H2O2 application site. The number of polymorphonuclear leukocytes (PMN had increased significantly 1 hour after application of 38% H2O2 (p<0.05, while macrophages had significantly increased 5 days after the application (p<0.05. The most intense PMN and macrophages infiltration was found 5 days after the application and gradually decreased 8 days after application of38% H2O2. Conclusion: Application of 38% H2O2 as a vital tooth bleaching agent induces acute inflammation in human dental pulp; however, the inflammation will decrease 8 days after the application.Latar belakang: Perawatan pemutihan gigi vital metode in-office merupakan tindakan untuk menghilangkan pewarnaan pada gigi. Salah satu efek samping yang sering dikeluhkan oleh pasien yang menjalani perawatan ini adalah sensitivitas gigi. Tujuan: Penelitian ini bertujuan untuk mengamati infiltrasi sel inflamasi pada pulpa gigi setelah aplikasi H2O2 38% sebagai bahan pemutih gigi. Metode: Sampel penelitian ini berupa 15 gigi premolar yang berasal dari 8

  16. [Activities of the National Information Center for Biological Agents present at workplace and preliminary analysis of data collected by the National Register of Biological Agents].

    Science.gov (United States)

    Kozajda, Anna; Szadkowska-Stańczyk, Irena

    2009-01-01

    The National Information Centre for Biological Agents Present at Workplaces and the National Register of Biological Agents were established in the Nofer Institute of Occupational Medicine in 2005. The former carries out consultation and education activities concerned with occupational exposure and risk assessment, planning and implementation of preventive programs and accurate registration of reliable information about the use of biological agents. The latter aims at collecting and analyzing the aforesaid information obtained from employers for research, diagnostic or industrial purposes. The data base is a source of information for occupational environment supervising inspections and occupational health service. useful among others in planning various forms of prevention. As of December 10, 2008 there were 281 notifications from companies using biological agents (for the following purposes: research--34, diagnostic--225 and industrial--22). The majority of notifications were obtained from different diagnostic laboratories and universities/ research institutes. In total, 2197 workers, including 2011 (91.5%) women and 186 (8.5%) men were exposed to biological agents, were registered.

  17. Influence of intermediary filling material on microleakage of intracoronally bleached and restored teeth

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2009-01-01

    Full Text Available Background: Failure of composite restorations in terms of microleakage after intracoronal bleaching has been reported. The purpose of this study was to assess in vitro effect of sodium ascorbate and calcium hydroxide as intermediary filling materials to repair the microleakage associated with adhe-sive restoration following intracoronal bleaching. Methods: Sixty endodontically-treated incisors with access cavities extended to the cementoenamel junction in gingival margin were randomly divided into five equal groups. In group 1, cavities were restored by applying Single Bond and Z100 composite resin. In groups 2-5, 35% hydrogen peroxide gel was placed into the pulp chamber and sealed for 5 days. In group 2, teeth were then restored as in group 1. In groups 3 and 4, 10% sodium ascorbate gel and calcium hydroxide paste were applied in the pulp chamber for 40 hours, removed, rinsed and then, restored. In group 5, the cavities were incu-bated for 7 days and then, restored. Samples were thermocycled, immersed in basic fuschin, and sec-tioned. Dye penetration was scored using a stereomicroscope. Data were analyzed using Kruskal- Wallis and Mann-Whitney U tests (α = 0.05. Results: There was no significant difference in enamel margins (P = 0.163. In dentinal margins (P = 0.003, groups 1, 3 and 5 exhibited similar leakage patterns, each one of groups 1, 3 and 5 had sig-nificant differences with each one of groups 2 and 4. Conclusion: Intracoronal bleaching using 35% H2O2 gel increases the microleakage in dentinal margins. Application of the antioxidant agent or a seven-day delay following bleaching may improve the marginal integrity. Applying calcium hydroxide might jeopardize dentinal sealing.

  18. The effect of two in-office and home bleaching gels on microhardness of composite resin

    Directory of Open Access Journals (Sweden)

    Alizadeh Oskoee P.

    2007-07-01

    Full Text Available Background and Aim: Bleaching products as chemical materials can exert side effects on soft and hard tissues and existing restorative materials with oxidizing mechanism. The aim of this study was to evaluate the effect of 15% and 35% carbamide peroxide gels as home and in-office bleaching agents respectively, on microhardness and surface topography of composite resin.Materials and Methods: In this in vitro study, a total of 75 disc shaped specimens were prepared from Z100  composite resin (3M and randomly divided into three groups with following treatment designs: group 1, 370C distilled water, group 2, 15% carbamide peroxide, 6 hours/day for 3 weeks, group 3, 35% carbamide peroxide 30 minutes/week for 3 weeks. The microhardness (Vickers hardness of samples was measured using Shimadzu set on three different points of each sample. 8 samples of each group were selected randomly to be assessed by scanning electron microscopy (SEM for probable changes in surface topography. Data were analyzed using one way ANOVA and Duncan tests with p<0.05 as the level of significance. Results: 15% carbamide peroxide group had the maximum amount of microhardness (84.59±1.87 and 35% carbamide peroxide group had the minimum (76. 14±1.77. Only the difference between home bleaching and control group was not statistically significant (P=0.24. The SEM assessing revealed no changes in surface topography.Conclusion: Based on the results of this study, in-office bleaching may decrease the microhardness of composite resin.

  19. The application of click chemistry in the synthesis of agents with anticancer activity

    Directory of Open Access Journals (Sweden)

    Ma N

    2015-03-01

    Full Text Available Nan Ma,1–3 Ying Wang,3 Bing-Xin Zhao,3 Wen-Cai Ye,1,3 Sheng Jiang2 1Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, 2Laboratory of Medicinal Chemistry, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, 3Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, People’s Republic of China Abstract: The copper(I-catalyzed 1,3-dipolar cycloaddition between alkynes and azides (click chemistry to form 1,2,3-triazoles is the most popular reaction due to its reliability, specificity, and biocompatibility. This reaction has the potential to shorten procedures, and render more efficient lead identification and optimization procedures in medicinal chemistry, which is a powerful modular synthetic approach toward the assembly of new molecular entities and has been applied in anticancer drugs discovery increasingly. The present review focuses mainly on the applications of this reaction in the field of synthesis of agents with anticancer activity, which are divided into four groups: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, and antimicrotubule agents. Keywords: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, antimicrotubule agents

  20. Agents that activate the High Osmolarity Glycerol pathway as a means to combat pathogenic molds.

    Science.gov (United States)

    Wiedemann, Annegret; Spadinger, Anja; Löwe, Axel; Seeger, Allison; Ebel, Frank

    2016-12-01

    Treatment of invasive fungal infections often fails due to the limited number of therapeutic options. In this study, we have analyzed the impact of agents activating the High Osmolarity Glycerol (HOG) pathway on molds that cause infections in humans and livestock. We found that agents like fludioxonil and iprodione, have a clear anti-fungal activity against pathogenic Aspergillus, Lichtheimia, Rhizopus and Scedosporium species. Only A. terreus turned out to be resistant to fludioxonil, even though it is sensitive to iprodione and able to adapt to hyperosmotic conditions. Moreover, the A. terreus tcsC gene can fully complement an A. fumigatus ΔtcsC mutant, thereby also restoring its sensitivity to fludioxonil. The particular phenotype of A. terreus is therefore likely to be independent of its TcsC kinase. In a second part of this study, we further explored the impact of fludioxonil using A. fumigatus as a model organism. When applied in concentrations of 1-2μg/ml, fludioxonil causes an immediate growth arrest and, after longer exposure, a quantitative killing. Hyphae respond to fludioxonil by the formation of new septa and closure of nearly all septal pores. Mitosis occurs in all compartments and is accompanied by a re-localization of the NimA kinase to the cytoplasm. In the swollen compartments, the massive extension of the cell wall triggers a substantial reorganization resulting in an enhanced incorporation of chitin and, most strikingly, a massive loss of galactomannan. Hence, HOG-activating agents have dramatic cell biological consequences and may represent a valuable, future element in the armory that can be used to combat mold infections.

  1. Removal of gadolinium-based contrast agents: adsorption on activated carbon.

    Science.gov (United States)

    Elizalde-González, María P; García-Díaz, Esmeralda; González-Perea, Mario; Mattusch, Jürgen

    2017-01-31

    Three carbon samples were employed in this work, including commercial (1690 m(2) g(-1)), activated carbon prepared from guava seeds (637 m(2) g(-1)), and activated carbon prepared from avocado kernel (1068 m(2) g(-1)), to study the adsorption of the following gadolinium-based contrast agents (GBCAs): gadoterate meglumine Dotarem®, gadopentetate dimeglumine Magnevist®, and gadoxetate disodium Primovist®. The activation conditions with H3PO4 were optimized using a Taguchi methodology to obtain mesoporous materials. The best removal efficiency by square meter in a batch system in aqueous solution and model urine was achieved by avocado kernel carbon, in which mesoporosity prevails over microporosity. The kinetic adsorption curves were described by a pseudo-second-order equation, and the adsorption isotherms in the concentration range 0.5-6 mM fit the Freundlich equation. The chemical characterization of the surfaces shows that materials with a greater amount of phenolic functional groups adsorb the GBCA better. Adsorption strongly depends on the pH due to the combination of the following factors: contrast agent protonated forms and carbon surface charge. The tested carbon samples were able to adsorb 70-90% of GBCA in aqueous solution and less in model urine. This research proposes a method for the elimination of GBCA from patient urine before its discharge into wastewater.

  2. Active Power Control Simulation Platform Research of Wind Farm Based on Multi-Agent

    Directory of Open Access Journals (Sweden)

    Liu Xingjie

    2015-01-01

    Full Text Available The realization of the automation, routinization and intelligentization of dispatch control in wind farms is the key to the integration of wind farms into power grid management system. Active power regulate and control system in wind farms has increasingly high demand on timeliness, but at present this system is mostly equipped with centralized unidirectional control with poor timeliness and low utilization ratio for wind energy resources. The characteristics of distribution and instantaneity owned by the active power regulate and control system in wind farms are highly consistent with Multi-Agent system. This paper discusses a kind of processing method that is used in real-time, distributed and parallel computation and processing for multiple simultaneously running wind turbines, which is based on Multi-Agent technology and adopting JADE development platform. This method converts massive centralized computation to distributed computation, which optimizes the effect of the power control. This method makes the effectiveness of active power regulate and control system better, wins time for timely allocating electricity generation assignments and dealing with problems, and avoids the heavy loss of resources.

  3. Telomerase activity and telomere length in human tumor cells with acquired resistance to anticancer agents.

    Science.gov (United States)

    Smith, V; Dai, F; Spitz, M; Peters, G J; Fiebig, H H; Hussain, A; Burger, A M

    2009-11-01

    Telomeres and telomerase are targets for anticancer drug development and specific inhibitors are currently under clinical investigation. However, it has been reported that standard cytotoxic agents can affect telomere length and telomerase activity suggesting that they also have of a role in drug resistance. in this study, telomere lengths and telomerase activity as well as drug efflux pump expression, glutathione (GSH) levels and polyadenosine-ribose polymerase (PARP) cleavage were assessed in a panel of human tumor cell lines made resistant to vindesine, gemcitabine and cisplatin. these included two lung cancer cell lines resistant to vindesine (LXFL 529L/Vind, LXFA 526L/Vind), a renal cancer cell line (RXF944L/Gem) and an ovarian cancer cell line (AG6000) resistant to gemcitabine, and one resistant to cisplatin (ADDP). The resistant clones were compared to their parental lines and evaluated for cross resistance to other cytotoxic agents. Several drug specific resistance patterns were found, and various complex patterns of cross resistance emerged from some cell lines, but these mechanisms of resistance could not be related to drug efflux pump expression, GSH levels or pARp cleavage. However, all displayed changes in telomerase activity and/or telomere length. Our studies present evidence that telomere maintenance should be taken into consideration in efforts not only to overcome drug resistance, but also to optimize the use of telomere-based therapeutics.

  4. Disposal of chemical agents and munitions stored at Umatilla Depot Activity, Hermiston, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, G.P.; Hillsman, E.L.; Johnson, R.O.; Miller, R.L.; Patton, T.G.; Schoepfle, G.M.; Tolbert, V.R.; Feldman, D.L.; Hunsaker, D.B. Jr.; Kroodsma, R.L.; Morrissey, J.; Rickert, L.W.; Staub, W.P.; West, D.C.

    1993-02-01

    The Umatilla Depot Activity (UMDA) near Hermiston, Oregon, is one of eight US Army installations in the continental United States where lethal unitary chemical agents and munitions are stored, and where destruction of agents and munitions is proposed under the Chemical Stockpile Disposal Program (CSDP). The chemical agent inventory at UMDA consists of 11.6%, by weight, of the total US stockpile. The destruction of the stockpile is necessary to eliminate the risk to the public from continued storage and to dispose of obsolete and leaking munitions. In 1988 the US Army issued a Final Programmatic Environmental Impact Statement (FPEIS) for the CSDP that identified on-site disposal of agents and munitions as the environmentally preferred alternative (i.e., the alternative with the least potential to cause significant adverse impacts), using a method based on five measures of risk for potential human health and ecosystem/environmental effects; the effectiveness and adequacy of emergency preparedness capabilities also played a key role in the FPEIS selection methodology. In some instances, the FPEIS included generic data and assumptions that were developed to allow a consistent comparison of potential impacts among programmatic alternatives and did not include detailed conditions at each of the eight installations. The purpose of this Phase 1 report is to examine the proposed implementation of on-site disposal at UMDA in light of more recent and more detailed data than those included in the FPEIS. Specifically, this Phase 1 report is intended to either confirm or reject the validity of on-site disposal for the UMDA stockpile. Using the same computation methods as in the FPEIS, new population data were used to compute potential fatalities from hypothetical disposal accidents. Results indicate that onsite disposal is clearly preferable to either continued storage at UMDA or transportation of the UMDA stockpile to another depot for disposal.

  5. Synthesis and biological activity of trans-tiliroside derivatives as potent anti-diabetic agents.

    Science.gov (United States)

    Zhu, Yujin; Zhang, Yanjun; Liu, Yi; Chu, Hongwan; Duan, Hongquan

    2010-12-10

    A set of novel trans-tiliroside derivatives were synthesized. The structures of the derivatives were identified by their IR, 1H-NMR, and MS spectra analysis. Their anti-diabetic activities were evaluated on the insulin resistant (IR) HepG2 cell model. As a result, compounds 7a, 7c, 7h, and trans-tiliroside exhibited significant glucose consumption-enhancing effects in IR-HepG2 cells compared with the positive control (metformin). This research provides useful clues for further design and discovery of anti-diabetic agents.

  6. Synthesis and Biological Activity of trans-Tiliroside Derivatives as Potent Anti-Diabetic Agents

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2010-12-01

    Full Text Available A set of novel trans-tiliroside derivatives were synthesized. The structures of the derivatives were identified by their IR, 1H-NMR, and MS spectra analysis. Their anti-diabetic activities were evaluated on the insulin resistant (IR HepG2 cell model. As a result, compounds 7a, 7c, 7h, and trans-tiliroside exhibited significant glucose consumption-enhancing effects in IR-HepG2 cells compared with the positive control (metformin. This research provides useful clues for further design and discovery of anti-diabetic agents.

  7. Effect of polyester blends in hydroentangled raw and bleached cotton nonwoven fabrics on the adsorption of alkyl-dimethyl-benzyl-ammonium chloride

    Science.gov (United States)

    The adsorption kinetics and isotherms of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on hydroentangled nonwoven fabrics (applicable for wipes) including raw cotton, bleached cotton, and their blends with polyester (PES) were stu...

  8. Chemical alteration by tooth bleaching of human salivary proteins that infiltrated subsurface enamel lesions: experimental study with bovine lesion model systems

    NARCIS (Netherlands)

    Iizuka, J.; Mukai, Y.; Taniguchi, M.; ten Cate, J.M.; Mikuni-Takagaki, Y.; Teranaka, T.

    2014-01-01

    Salivary macromolecules infiltrate white and brown spot enamel lesions and adsorb onto hydroxyapatite. Calcium-binding salivary proteins such as statherin hinder remineralization of these lesions. We assessed whether bleaching agents can remove salivary components that have infiltrated and bound to

  9. Silver nanoparticles-loaded activated carbon fibers using chitosan as binding agent: Preparation, mechanism, and their antibacterial activity

    Science.gov (United States)

    Tang, Chengli; Hu, Dongmei; Cao, Qianqian; Yan, Wei; Xing, Bo

    2017-02-01

    The effective and strong adherence of silver nanoparticles (AgNPs) to the substrate surface is pivotal to the practical application of those AgNPs-modified materials. In this work, AgNPs were synthesized through a green and facile hydrothermal method. Chitosan was introduced as the binding agent for the effective loading of AgNPs on activated carbon fibers (ACF) surface to fabricate the antibacterial material. Apart from conventional instrumental characterizations, i. e., scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), zeta potential and Brunauer-Emmett-Teller (BET) surface area measurement, molecular dynamics simulation method was also applied to explore the loading mechanism of AgNPs on the ACF surface. The AgNPs-loaded ACF material showed outstanding antibacterial activity for S. aureus and E. coli. The combination of experimental and theoretical calculation results proved chitosan to be a promising binding agent for the fabrication of AgNPs-loaded ACF material with excellent antibacterial activity.

  10. Enhancing activated-peroxide formulations for porous materials :

    Energy Technology Data Exchange (ETDEWEB)

    Krauter, Paula; Tucker, Mark D.; Tezak, Matthew S.; Boucher, Raymond

    2012-12-01

    During an urban wide-area incident involving the release of a biological warfare agent, the recovery/restoration effort will require extensive resources and will tax the current capabilities of the government and private contractors. In fact, resources may be so limited that decontamination by facility owners/occupants may become necessary and a simple decontamination process and material should be available for this use. One potential process for use by facility owners/occupants would be a liquid sporicidal decontaminant, such as pHamended bleach or activated-peroxide, and simple application devices. While pH-amended bleach is currently the recommended low-tech decontamination solution, a less corrosive and toxic decontaminant is desirable. The objective of this project is to provide an operational assessment of an alternative to chlorine bleach for low-tech decontamination applications activated hydrogen peroxide. This report provides the methods and results for activatedperoxide evaluation experiments. The results suggest that the efficacy of an activated-peroxide decontaminant is similar to pH-amended bleach on many common materials.

  11. CONSENSUS OF THE SECOND-ORDER MULTI-AGENT SYSTEMS WITH AN ACTIVE LEADER AND COUPLING TIME DELAY

    Institute of Scientific and Technical Information of China (English)

    郭万里; 肖海军; 陈士华

    2014-01-01

    This article investigates the consensus problem of the second-order multi-agent systems with an active leader and coupling time delay in direct graph. One decentralized state control rule is constructed for each agent to track the active leader and it is proved that the proposed control scheme enables the consensus to be obtained when the adjacency topology is fixed/switched. Simulation results show effectiveness of the proposed theoretical analysis.

  12. Activation of a unique flavin-dependent tRNA-methylating agent.

    Science.gov (United States)

    Hamdane, Djemel; Bruch, Eduardo; Un, Sun; Field, Martin; Fontecave, Marc

    2013-12-10

    TrmFO is a tRNA methyltransferase that uses methylenetetrahydrofolate (CH2THF) and flavin adenine dinucleotide hydroquinone as cofactors. We have recently shown that TrmFO from Bacillus subtilis stabilizes a TrmFO-CH2-FADH adduct and an ill-defined neutral flavin radical. The adduct contains a unique N-CH2-S moiety, with a methylene group bridging N5 of the isoalloxazine ring and the sulfur of an active-site cysteine (Cys53). In the absence of tRNA substrate, this species is remarkably stable but becomes catalytically competent for tRNA methylation following tRNA addition using the methylene group as the source of methyl. Here, we demonstrate that this dormant methylating agent can be activated at low pH, and we propose that this process is triggered upon tRNA addition. The reaction proceeds via protonation of Cys53, cleavage of the C-S bond, and generation of a highly reactive [FADH(N5)═CH2]+ iminium intermediate, which is proposed to be the actual tRNA-methylating agent. This mechanism is fully supported by DFT calculations. The radical present in TrmFO is characterized here by optical and EPR/ENDOR spectroscopy approaches together with DFT calculations and is shown to be the one-electron oxidized product of the TrmFO-CH2-FADH adduct. It is also relatively stable, and its decomposition is facilitated by high pH. These results provide new insights into the structure and reactivity of the unique flavin-dependent methylating agent used by this class of enzymes.

  13. Induction of megakaryocytic colony-stimulating activity in mouse skin by inflammatory agents and tumor promoters

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D.A.; Dessypris, E.N.; Koury, M.J.

    1987-03-01

    The production of megakaryocytic colony-stimulating activity (MEG-CSA) was assayed in acetic acid extracts of skin from mice topically treated with inflammatory and tumor-promoting agents. A rapid induction of MEG-CSA was found in skin treated both with phorbol 12-myristate 13-acetate (PMA), a strong tumor promoter, and with mezerein, a weak tumor promoter, but no induction was found in untreated skin. The time course of induction of MEG-CSA following treatment of skin with PMA or mezerein was very similar to that previously demonstrated for the induction of granulocyte-macrophage colony-stimulating activity in mouse skin by these agents. The induced MEG-CSA was found in both the epidermis and the dermis. Pretreatment of the skin with US -methasone abrogated the MEG-CSA induction. The cell number response curve suggests that the MEG-CSA acts directly on the progenitor cells of the megakaryocyte colonies. That topical administration of diterpene esters results in the rapid, local induction of MEG-CSA which can be blocked by US -methasone pretreatment suggests a mechanism for the thrombocytosis associated with some inflammatory states. The indirect action in which diterpene esters induce in certain cells the production or release of growth regulatory factors for other cell types may also aid in understanding their carcinogenic properties.

  14. An artemisinin derivative of praziquantel as an orally active antischistosomal agent.

    Directory of Open Access Journals (Sweden)

    Lanlan Dong

    Full Text Available Schistosomiasis is a major health problem in tropical and sub-tropical areas caused by species of trematode belonging to the genus Schistosoma. The treatment and control of this disease has been relying on the use of a single drug praziquantel. However, the drug resistance concern urged the development of new drugs against schistosoma. Here, we report our systematic biological evaluation of DW-3-15, a new lead compound developed based on our conjugation design rationale as an effective anti-schistosomal agent.The antischistosomal activity of DW-3-15 was systematically evaluated in S. japonicum infected mouse model for its stage-sensitivity and dose response. The results revealed that DW-3-15 exhibited 60-85% worm reduction rate against different development stage of worm. Scanning electron microscopy (SEM observation indicated that DW-3-15 may damage to the tegument of male schistosomes.Our results demonstrated that DW-3-15 showed potent anti-schistosomal activities in vivo. The results strongly support our conjugation design strategy of artemisinin analogs and further development of DW-3-15 as a new lead compound as anti-schistosomal agent.

  15. Walk This Way: Improving Pedestrian Agent-Based Models through Scene Activity Analysis

    Directory of Open Access Journals (Sweden)

    Andrew Crooks

    2015-09-01

    Full Text Available Pedestrian movement is woven into the fabric of urban regions. With more people living in cities than ever before, there is an increased need to understand and model how pedestrians utilize and move through space for a variety of applications, ranging from urban planning and architecture to security. Pedestrian modeling has been traditionally faced with the challenge of collecting data to calibrate and validate such models of pedestrian movement. With the increased availability of mobility datasets from video surveillance and enhanced geolocation capabilities in consumer mobile devices we are now presented with the opportunity to change the way we build pedestrian models. Within this paper we explore the potential that such information offers for the improvement of agent-based pedestrian models. We introduce a Scene- and Activity-Aware Agent-Based Model (SA2-ABM, a method for harvesting scene activity information in the form of spatiotemporal trajectories, and incorporate this information into our models. In order to assess and evaluate the improvement offered by such information, we carry out a range of experiments using real-world datasets. We demonstrate that the use of real scene information allows us to better inform our model and enhance its predictive capabilities.

  16. Evaluation of peanut hulls as an alternative to bleaching clays

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, M. M.; El-Shami, S. M.; Taha, F. S.

    2011-07-01

    Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller's earth (FE) and PNH and O-passive (OP) and examined. The oxidative stability of oils was determined. Results for the investigated commercial bleaching clays revealed: TN > FE > F > TF > OP. Highest reduction in PV and PL, and highest bleachability were achieved for soybean oil bleached with 2% PNH carbonized at 500 degree centigrade for 30 min (PNH). Mixtures of PNH with the three chosen bleaching clays indicated that 1PNH : 2TN gave the highest bleachability. CSO was miscella bleached in hexane using PNH and resulted in an appreciable improvement in all oil characteristics, especially in bleachability. Oxidative stability of oils was in the following order: TN > control > FE > PNH with Induction period values of 23.1 > 6.43 > 5.73 > 2.85 h, respectively. (Author) 20 refs.

  17. ECF AND TCF BLEACHING OF SECONDARY FIBER PULP

    Directory of Open Access Journals (Sweden)

    Gustavo Ventorim

    2009-09-01

    Full Text Available In this study, ECF and TCF bleaching processes were evaluated for the bleaching of a deinked mixed office waste (MOW pulp sample produced in a pilot plant. The sample was bleached by all processes to a target brightness of 78 % ISO minimum. The results were interpreted on the basis of chemical cost to reach the target brightness, bleaching yield and bleached pulp quality as measured by viscosity, fluorescence and b* color coordinate. Among the ECF sequences, the mosattractive was the DEDD which showed the lowest chemical cost and produced bleached pulp of high quality as measured by viscosity, fluorescence and b* coordinate. The best TCF sequence with ozone was the Q(PO(ZQ(PO which resulted in very high brightness ceiling. This sequence decreased moderately the pulp b* coordinate and viscosity and slightly its fluorescence. Among the TCF sequences without ozone the Q(POQ(PO was the most effective but showed poor flexibility with regard to brightness ceiling. This sequence had little effect on pulp viscosity, fluorescence and b* coordinate. For all three  bleaching processes, it was determined that process yield is negatively affected by hot alkaline stages such as O, P and (PO.

  18. Is It Necessary to Prepare the Enamel before Dental Bleaching?

    Science.gov (United States)

    Araújo, Erika Michele dos Santos; Garone-Netto, Narciso

    2017-01-01

    The aim of this in vitro study was to assess the influence of distinct surface treatments on the microhardness and color of enamel that will be bleached. Surface treatments are tested, accordingly: G1, no treatment; G2, 2% sodium fluoride; G3, casein phosphopeptide paste; G4, 2% fluoride+Nd:YAG laser. Forty blocks from bovine teeth composed the sample that were tested in Knoop microhardness (n = 10) and in color change (n = 10). After 24 h, bleaching with 35% hydrogen peroxide was performed for 45 min. Microhardness and color changes (using parameters ΔE, ΔL, Δa, and Δb) were assessed before and after bleaching. The data were analyzed by two-way ANOVA and Tukey's test (p microhardness occurred immediately after bleaching in all groups, being greater in G1. Enamel color changed in all groups. Immediately after bleaching, there was a decrease on enamel microhardness. However, after 7 days, some of those specimens previously treated before bleaching significantly recovered their initial microhardness without influencing the esthetic results of bleaching. PMID:28280508

  19. Synthesis and in vitro antitumor activity of substituted quinazoline and quinoxaline derivatives: search for anticancer agent.

    Science.gov (United States)

    Noolvi, Malleshappa N; Patel, Harun M; Bhardwaj, Varun; Chauhan, Ankit

    2011-06-01

    The synthesis of some 2-furano-4(3H)-quinazolinones, diamides (open ring quinazolines), quinoxalines and their biological evaluation as antitumor agents using National Cancer Institute (NCI) disease oriented antitumor screen protocol are investigated. Among the synthesize compounds, seventeen compounds were granted NSC code and screened at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10(-5) M) in full NCI 60 cell panel. Among the selected compounds, 3-(2-chloro benzylideneamine)-2-(furan-2-yl) quinazoline-4(3h)-one 21 was found to be the most active candidate of the series at five dose level screening against Ovarian OVCAR-4 and Non-small cell lung cancer NCI-H522 with GI50 1.82 & 2.14 μM respectively. Rational approach and QSAR techniques enabled the understanding of the pharmacophoric requirement for quinazoline, diamides and quinoxaline derivatives.

  20. Orally Active and Selective Tubulin Inhibitors as Anti-Trypanosome Agents.

    Directory of Open Access Journals (Sweden)

    Vishal Nanavaty

    Full Text Available There is an urgent need to develop a safe, effective, orally active, and inexpensive therapy for African trypanosomiasis due to the drawbacks of current drugs. Selective tubulin inhibitors have the potential to be promising drug candidates for the treatment of this disease, which is based on the tubulin protein structural difference between mammalian and trypanosome cells. We propose to identify novel tubulin inhibitors from a compound library developed based on the lead compounds that selectively target trypanosomiasis.We used Trypanosoma brucei brucei as the parasite model, and human normal kidney cells and mouse microphage cells as the host model. Growth rates of both trypanosomes and mammalian cells were determined as a means to screen compounds that selectively inhibit the proliferation of parasites. Furthermore, we examined the cell cycle profile of the parasite and compared tubulin polymerization dynamics before and after the treatment using identified compounds. Last, in vivo anti-parasite activities of these compounds were determined in T. brucei-infected mice.Three compounds were selected that are 100 fold more effective against the growth of T. brucei cells than mammalian cells. These compounds caused cell cycle progression defects in T. brucei cells. Western analyses indicated that these compounds decreased tubulin polymerization in T. brucei cells. The in vivo investigation revealed that these compounds, when admitted orally, inhibited T. brucei cell proliferation in mouse blood. However, they were not potent enough to clear up the infection completely.These compounds are promising lead compounds as orally active agents for drug development of anti-trypanosome agents. A more detail structure activity relationship (SAR was summarized that will be used to guide future lead optimization to improve the selectivity and potency of the current compounds.

  1. Regulation of apoptotic pathways by Stylophora pistillata (Anthozoa, Pocilloporidae to survive thermal stress and bleaching.

    Directory of Open Access Journals (Sweden)

    Hagit Kvitt

    Full Text Available Elevated seawater temperatures are associated with coral bleaching events and related mortality. Nevertheless, some coral species are able to survive bleaching and recover. The apoptotic responses associated to this ability were studied over 3 years in the coral Stylophora pistillata from the Gulf of Eilat subjected to long term thermal stress. These include caspase activity and the expression profiles of the S. pistillata caspase and Bcl-2 genes (StyCasp and StyBcl-2-like cloned in this study. In corals exposed to thermal stress (32 or 34°C, caspase activity and the expression levels of the StyBcl-2-like gene increased over time (6-48 h and declined to basal levels within 72 h of thermal stress. Distinct transcript levels were obtained for the StyCasp gene, with stimulated expression from 6 to 48 h of 34°C thermal stress, coinciding with the onset of bleaching. Increased cell death was detected in situ only between 6 to 48 h of stress and was limited to the gastroderm. The bleached corals survived up to one month at 32°C, and recovered back symbionts when placed at 24°C. These results point to a two-stage response in corals that withstand thermal stress: (i the onset of apoptosis, accompanied by rapid activation of anti-oxidant/anti-apoptotic mediators that block the progression of apoptosis to other cells and (ii acclimatization of the coral to the chronic thermal stress alongside the completion of symbiosis breakdown. Accordingly, the coral's ability to rapidly curb apoptosis appears to be the most important trait affecting the coral's thermotolerance and survival.

  2. Perbedaan Penggunaan Bahan Desensitizing dan Tanpa Desensitizing Pasca Bleaching Ekstra-Koronal terhadap Kekerasan Email

    Directory of Open Access Journals (Sweden)

    Wignyo Hadriyanto

    2012-12-01

    dibandingkan tanpa aplikasi ultraEZ terhadap kekerasan email pada p>0,05.   Background. One of the side effect of bleaching agent is a dentine hypersensitive and ultraEZ is an agent can diminish this process. The purpose of this study was to evaluate difference of enamel microhardness post external bleaching with or without ultra-eze application. Method. Twenty extracted permanent bicuspid used in this study were divided into two group, each group contains 10 bicupids. Group I was treated external bleaching without ultra-eze application and group II was treated external bleaching with application ultraEZ for five minutes. After that all of the subject were seaked the artificial saliva and kept in the incubator 24 hours. Teeth were embedded into acrylic resin with the buccal sirface facing up. Further all of the subject was evaluated by Vickers using 100 g load for 15 seconds. Teeth were stapled on the Micro Hardness Tester table diagonal of emage was measure using micrometer attach on ocular lesnse. Email hardness can be known after calculating, the everage diagonal length, the load used and the duration of hardness test. Further the data was analize using t-test. The result shows there is significant difference between bleaching with and without the application of ultra-eze.

  3. Study of Melanin Bleaching After Immunohistochemistry of Melanin-containing Tissues

    OpenAIRE

    2015-01-01

    Melanin may interfere with immunohistochemical staining. The goal of this study was to investigate the effects of trichloroisocyanuric acid (TCCA) bleaching, potassium permanganate bleaching, and potassium dichromate bleaching on melanin, tissue antigen, and 3,3′-diaminobenzidine (DAB) using melanin-containing and melanin-free tissue samples. Our results demonstrated that all 3 bleaching methods efficiently bleached melanin and partially destroyed tissue antigen. In addition, potassium perman...

  4. Antiviral activity of carbohydrate-binding agents against Nidovirales in cell culture.

    Science.gov (United States)

    van der Meer, F J U M; de Haan, C A M; Schuurman, N M P; Haijema, B J; Peumans, W J; Van Damme, E J M; Delputte, P L; Balzarini, J; Egberink, H F

    2007-10-01

    Coronaviruses are important human and animal pathogens, the relevance of which increased due to the emergence of new human coronaviruses like SARS-CoV, HKU1 and NL63. Together with toroviruses, arteriviruses, and roniviruses the coronaviruses belong to the order Nidovirales. So far antivirals are hardly available to combat infections with viruses of this order. Therefore, various antiviral strategies to counter nidoviral infections are under evaluation. Lectins, which bind to N-linked oligosaccharide elements of enveloped viruses, can be considered as a conceptionally new class of virus inhibitors. These agents were recently evaluated for their antiviral activity towards a variety of enveloped viruses and were shown in most cases to inhibit virus infection at low concentrations. However, limited knowledge is available for their efficacy towards nidoviruses. In this article the application of the plant lectins Hippeastrum hybrid agglutinin (HHA), Galanthus nivalis agglutinin (GNA), Cymbidium sp. agglutinin (CA) and Urtica dioica agglutinin (UDA) as well as non-plant derived pradimicin-A (PRM-A) and cyanovirin-N (CV-N) as potential antiviral agents was evaluated. Three antiviral tests were compared based on different evaluation principles: cell viability (MTT-based colorimetric assay), number of infected cells (immunoperoxidase assay) and amount of viral protein expression (luciferase-based assay). The presence of carbohydrate-binding agents strongly inhibited coronaviruses (transmissible gastroenteritis virus, infectious bronchitis virus, feline coronaviruses serotypes I and II, mouse hepatitis virus), arteriviruses (equine arteritis virus and porcine respiratory and reproductive syndrome virus) and torovirus (equine Berne virus). Remarkably, serotype II feline coronaviruses and arteriviruses were not inhibited by PRM-A, in contrast to the other viruses tested.

  5. Screening of pharmacologically active small molecule compounds identifies antifungal agents against Candida biofilms

    Directory of Open Access Journals (Sweden)

    Takao eWatamoto

    2015-12-01

    Full Text Available Candida species have emerged as important and common opportunistic human pathogens, particularly in immunocompromised individuals. The current antifungal therapies either have toxic side effects or are insufficiently effect. The aim of this study is develop new small-molecule antifungal compounds by library screening methods using C. albicans, and to evaluate their antifungal effects on Candida biofilms and cytotoxic effects on human cells. Wild-type C. albicans strain SC5314 was used in library screening. To identify antifungal compounds, we screened a small-molecule library of 1,280 pharmacologically active compounds (LOPAC1280TM using an antifungal susceptibility test (AST. To investigate the antifungal effects of the hit compounds, ASTs were conducted using Candida strains in various growth modes, including biofilms. We tested the cytotoxicity of the hit compounds using human gingival fibroblast (hGF cells to evaluate their clinical safety. Only 35 compounds were identified by screening, which inhibited the metabolic activity of C. albicans by >50%. Of these, 26 compounds had fungistatic effects and 9 compounds had fungicidal effects on C. albicans. Five compounds, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate, ellipticine and CV-3988, had strong fungicidal effects and could inhibit the metabolic activity of Candida biofilms. However, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate and ellipticine were cytotoxic to hGF cells at low concentrations. CV-3988 showed no cytotoxicity at a fungicidal concentration.Four of the compounds identified, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate and ellipticine, had toxic effects on Candida strains and hGF cells. In contrast, CV-3988 had fungicidal effects on Candida strains, but low cytotoxic effects on hGF cells. Therefore, this screening reveals agent, CV-3988 that was previously unknown to be antifungal agent, which could be a novel therapies for superficial mucosal

  6. Papermaking fibers from giant reed (Arundo donax L. by advanced ecologically friendly pulping and bleaching technologies

    Directory of Open Access Journals (Sweden)

    Pereira, H.

    2006-07-01

    Full Text Available The anatomical structure and chemical composition of the stem-wall material of giant reed is considered from the viewpoint of raw material characterization for industrial fiber production. The effect of stem morphology (nodes and internodes on pulping results and general pulp properties is discussed. The advantages of application of modern organic solvent based (organosolv pulping technologies to giant reed are shown in comparison with the conventional (kraft method. The conditions optimization for Ethanol-Alkali pulping (a selected organosolv pulping process is given, and the chemical kinetics of the principal macromolecular components during ethanol-alkali pulping is described. The bleachability of organosolv pulps by short totally chlorine free (TCF bleaching sequences using hydrogen peroxide and ozone as the active bleaching chemicals without pulp pre-delignification is examined and compared with kraft pulps. The enzymatic pre-treatment of reed organosolv pulps by commercial xylanase preparation is considered as a possibility toward the improvement of pulp bleachability.

  7. Highly effective bacterial agents against Cimbex quadrimaculatus (Hymenoptera: Cimbicidae): isolation of bacteria and their insecticidal activities.

    Science.gov (United States)

    Cakici, Filiz Ozkan; Ozgen, İnanc; Bolu, Halil; Erbas, Zeynep; Demirbağ, Zihni; Demir, İsmail

    2015-01-01

    Cimbex quadrimaculatus (Hymenoptera: Cimbicidae) is one of the serious pests of almonds in Turkey and worldwide. Since there is no effective control application against this pest, it has been a serious problem up to now. Therefore, we aimed to find an effective bacterium that can be utilized as a biocontrol agent against C. quadrimaculatus in pest management. We isolated seven bacteria from dead and live C. quadrimaculatus larvae, and evaluated the larvicidal potency of all isolates on the respective pest. Based on the morphological, physiological, biochemical and molecular properties (partial sequence of 16S rRNA gene), the isolates were identified to be Bacillus safensis (CQ1), Bacillus subtilis (CQ2), Bacillus tequilensis (CQ3), Enterobacter sp. (CQ4), Kurthia gibsonii (CQ5), Staphylococcus sp. (CQ6) and Staphylococcus sciuri (CQ7). The results of the larvicidal activities of these isolates indicated that the mortality value obtained from all treatments changed from 58 to 100 %, and reached 100 % with B. safensis (CQ1) and B. subtilis (CQ2) on the 3rd instar larvae within 10 days of application of 1.89 × 10(9) cfu/mL bacterial concentration at 25 °C under laboratory conditions. Findings from this study indicate that these isolates appear to be a promising biocontrol agent for C. quadrimaculatus.

  8. Toxicity and in vitro activity of HIV-1 latency-reversing agents in primary CNS cells.

    Science.gov (United States)

    Gray, Lachlan R; On, Hung; Roberts, Emma; Lu, Hao K; Moso, Michael A; Raison, Jacqueline A; Papaioannou, Catherine; Cheng, Wan-Jung; Ellett, Anne M; Jacobson, Jonathan C; Purcell, Damian F J; Wesselingh, Steve L; Gorry, Paul R; Lewin, Sharon R; Churchill, Melissa J

    2016-08-01

    Despite the success of combination antiretroviral therapy (cART), HIV persists in long lived latently infected cells in the blood and tissue, and treatment is required lifelong. Recent clinical studies have trialed latency-reversing agents (LRA) as a method to eliminate latently infected cells; however, the effects of LRA on the central nervous system (CNS), a well-known site of virus persistence on cART, are unknown. In this study, we evaluated the toxicity and potency of a panel of commonly used and well-known LRA (panobinostat, romidepsin, vorinostat, chaetocin, disulfiram, hexamethylene bisacetamide [HMBA], and JQ-1) in primary fetal astrocytes (PFA) as well as monocyte-derived macrophages as a cellular model for brain perivascular macrophages. We show that most LRA are non-toxic in these cells at therapeutic concentrations. Additionally, romidepsin, JQ-1, and panobinostat were the most potent at inducing viral transcription, with greater magnitude observed in PFA. In contrast, vorinostat, chaetocin, disulfiram, and HMBA all demonstrated little or no induction of viral transcription. Together, these data suggest that some LRA could potentially activate transcription in latently infected cells in the CNS. We recommend that future trials of LRA also examine the effects of these agents on the CNS via examination of cerebrospinal fluid.

  9. One-bath scouring and bleaching of cotton knits at low temperature%棉针织物——浴法低温练漂技术

    Institute of Scientific and Technical Information of China (English)

    杨雅蝶; 夏先广; 秦新波; 钟毅; 毛志平

    2013-01-01

    将有机类漂白活化剂和仿酶催化剂复配,制备出新型双氧水低温漂白复合活化剂,并将其应用于棉针织物双氧水低温练漂工艺.优化的复合活化剂低温练漂工艺为:30% H2O2 10 g/L,复合活化剂1.5 g/L,稳定剂PBTCA0.5g/L,低温精练剂1 g/L,NaOH 1 g/L,浴比10∶1,60℃处理60 min.该工艺处理后的织物白度可达71.44%,强力损失率为2.4%,与传统高温练漂工艺的处理效果接近;经活性染料染色,染色织物的表观深度、耐皂洗色牢度及耐干、湿摩擦牢度均可达到传统高温练漂工艺的效果.%A novel compound activator used for hydrogen peroxide bleaching at low temperature is prepared with organic bleaching activator and biomimetic catalyst,and then is applied to low-temperature scouring and bleaching of cotton knits in one bath.The optimum process is:30%H2O2 10 g/L,compound activator 1.5 g/L,stabilizer PBTCA 0.5 g/L,low-temperature scouring agent 1 g/L,NaOH 1 g/L,treating at 60 ℃ for 60 min with liquor ratio of 10 ∶ 1.The whiteness and strength loss of semi-products with low temperature process are 71.44% and 2.4% respectively,and the reactive cotton dyeings feature good color yield and color fastness to soaping and rubbing,which are similar to those with traditional high temperature process.

  10. Human recombinant truncated RNASET2, devoid of RNase activity; A potential cancer therapeutic agent

    Science.gov (United States)

    Nesiel-Nuttman, Liron; Schwartz, Betty; Shoseyov, Oded

    2014-01-01

    Human RNASET2 has been implicated in antitumorigenic and antiangiogenic activities, independent of its ribonuclease capacities. We constructed a truncated version of human RNASET2, starting at E50 (trT2-50) and devoid of ribonuclease activity. trT2-50 maintained its ability to bind actin and to inhibit angiogenesis and tumorigenesis. trT2-50 binds to cell surface actin and formed a complex with actin in vitro. The antiangiogenic effect of this protein was demonstrated in human umbilical vein endothelial cells (HUVECs) by its ability to arrest tube formation on Matrigel, induced by angiogenic factors. Immunofluorescence staining of HUVECs showed nuclear and cytosolic RNASET2 protein that was no longer detectable inside the cell following trT2-50 treatment. This effect was associated with disruption of the intracellular actin network. trT2-50 co-localized with angiogenin, suggesting that both molecules bind (or compete) for similar cellular epitopes. Moreover, trT2-50 led to a significant inhibition of tumor development. Histological analysis demonstrated abundant necrotic tissue and a substantial loss of endothelial structure in trT2-50-treated tumors. Collectively, the present results indicate that trT2-50, a molecule engineered to be deficient of its catalytic activity, still maintained its actin binding and anticancer-related biological activities. We therefore suggest that trT2-50 may serve as a potential cancer therapeutic agent. PMID:25426551

  11. N-Substituted piperazinyl quinolones as potential cytotoxic agents: structure-activity relationships study.

    Science.gov (United States)

    Foroumadi, Alireza; Emami, Saeed; Rajabalian, Saeed; Badinloo, Marziyeh; Mohammadhosseini, Negar; Shafiee, Abbas

    2009-03-01

    As part of a continuing search for new potential anticancer candidates in the piperazinyl quinolone series, the cytotoxicity evaluation of new N-substituted piperazinyl quinolones was of our interest. The growth inhibitory activities of 12 new compounds, namely N-[2-(5-chlorothiophen-2-yl)-2-oxoethyl] and N-[2-(5-chlorothiophen-2-yl)-2-oxyiminoethyl] piperazinyl quinolones 1-12 were determined against six cancer cell lines using MTT colorimetric assay. Preliminary screening showed that most of the new N-[2-(5-chlorothiophen-2-yl)ethyl]piperazinyl quinolones 4-12 containing (un)substituted oxime moiety showed significant cytotoxic activity and the modification of functionality on ethyl spacer produced a relatively minor change of activity. Thus, in the piperazinyl quinolone series, cytotoxic activity can be positively modulated through the introduction of 2-(5-chlorothiophen-2-yl)ethyl residue on the piperazine ring. The results revealed that the introduction of 2-(5-chlorothiophen-2-yl)ethyl moiety on the piperazine ring of quinolone antibacterials (ciprofloxacin, norfloxacin and enoxacin) changes the biological profile of piperazinyl quinolones from antibacterials to cytotoxic agents.

  12. Atividade in vitro do extrato de própolis contra agentes bacterianos da mastite bovina In vitro activity of propolis extract against bovine mastitis bacterial agents

    Directory of Open Access Journals (Sweden)

    Andrea Pinto Loguercio

    2006-02-01

    Full Text Available Este trabalho foi desenvolvido com o objetivo de avaliar a atividade in vitro do extrato alcoólico de própolis, contra agentes da mastite bovina, comparando-o aos principais antimicrobianos utilizados no tratamento convencional. Foram utilizados 36 isolados coagulase-positivos de Staphylococcus sp. e 27 isolados de Streptococcus sp.; 94,4% dos Staphylococcus sp. e 85,2% dos Streptococcus sp. foram susceptíveis ao extrato de própolis.The present study aimed to determine the in vitro activity of propolis extract, comparing it to the most common antibacterial drugs against bovine mastitis bacterial agents. Thirty-six isolates of coagulase-positive Staphylococcus sp. and twenty-seven of Streptococcus sp. were analyzed. Coagulase-positive Staphylococcus (94.4% and Streptococcus sp. (85.2% showed susceptibility to propolis extract.

  13. "Super-quenching" state protects Symbiodinium from thermal stress - Implications for coral bleaching.

    Science.gov (United States)

    Slavov, Chavdar; Schrameyer, Verena; Reus, Michael; Ralph, Peter J; Hill, Ross; Büchel, Claudia; Larkum, Anthony W D; Holzwarth, Alfred R

    2016-06-01

    The global rise in sea surface temperatures causes regular exposure of corals to high temperature and high light stress, leading to worldwide disastrous coral bleaching events (loss of symbiotic dinoflagellates (Symbiodinium) from reef-building corals). Our picosecond chlorophyll fluorescence experiments on cultured Symbiodinium clade C cells exposed to coral bleaching conditions uncovered the transformations of the alga's photosynthetic apparatus (PSA) that activate an extremely efficient non-photochemical "super-quenching" mechanism. The mechanism is associated with a transition from an initially heterogeneous photosystem II (PSII) pool to a homogeneous "spillover" pool, where nearly all excitation energy is transferred to photosystem I (PSI). There, the inherently higher stability of PSI and high quenching efficiency of P(700)(+) allow dumping of PSII excess excitation energy into heat, resulting in almost complete cessation of photosynthetic electron transport (PET). This potentially reversible "super-quenching" mechanism protects the PSA against destruction at the cost of a loss of photosynthetic activity. We suggest that the inhibition of PET and the consequent inhibition of organic carbon production (e.g. sugars) in the symbiotic Symbiodinium provide a trigger for the symbiont expulsion, i.e. bleaching.

  14. Clinical study of the safety and effectiveness of a novel over-the-counter bleaching tray system

    Directory of Open Access Journals (Sweden)

    Ghalili KM

    2014-02-01

    Full Text Available K Michael Ghalili,1 Kamal Khawaled,2 Doran Rozen,2 Veda Afsahi3 1Department of Prosthodontics, New York University College of Dentistry, New York, NY, USA; 2Department of R&D; Department of Clinical Affairs, Syneron Beauty, Ltd, Yokneam, Israel; 3Veda Faith Afsahi Inc., Fountain Valley, CA, USA Abstract: We investigated color change, gingival irritation, and tooth sensitivity in patients undergoing at-home vital tooth bleaching with a novel over-the-counter bleaching tray system. Tooth color shade in anterior teeth, supragingival plaque and gingivitis in Ramfjord teeth, as well as visual assessment of teeth gingival tissues and mucosa were evaluated in-office prior to treatment, after two consecutive applications of the 9% hydrogen peroxide bleaching product, after eight applications (10 minutes/day for 3 days at home, and after ten applications (50 minutes exposure over 5 days. Color stability was evaluated at 3 months after completing the treatment regimen. Over-the-counter bleaching products can be used by the patient at home without dentist supervision, but are frequently associated with gingival irritation and tooth sensitivity despite low concentrations of peroxide agents. Our investigations showed that the treatment is tolerable and safe with a low incidence of adverse effects. Any adverse effects associated with use of the whitening gel and tray are temporary, easily controlled, and often disappear within minutes of treatment. Statistical analysis revealed significant improvement in teeth whitening following treatment (mean color change of seven shades and at three months after treatment. Keywords: at home tooth-whitening, hydrogen peroxide teeth whitening, over-the-counter tooth-whitening, teeth bleaching

  15. Bleaching of the red anthocyanin induced by superoxide radical.

    Science.gov (United States)

    Yamasaki, H; Uefuji, H; Sakihama, Y

    1996-08-01

    Red anthocyanin prepared from petals of Hibiscus rosa-sinensis L. was photobleached in the EDTA-riboflavin system. The rate of bleaching monitored at 565 nm depended on the light intensity and EDTA concentrations. Anaerobic conditions and/or addition of superoxide dismutase prevented the bleaching of anthocyanin, whereas mannitol and catalase did not. A similar bleaching was observed under dark conditions in the xanthine-xanthine oxidase system. The results indicate that anthocyanin is bleached by the nonenzymatic reaction with the superoxide radical and suggest that the pigment can function as an antioxidant. The antioxidative efficiency of cyanidin to superoxide was 10-fold higher than that of cyanidin-3-sophoroside as a Hibiscus anthocyanin.

  16. Through bleaching and tsunami: Coral reef recovery in the Maldives.

    Science.gov (United States)

    Morri, Carla; Montefalcone, Monica; Lasagna, Roberta; Gatti, Giulia; Rovere, Alessio; Parravicini, Valeriano; Baldelli, Giuseppe; Colantoni, Paolo; Bianchi, Carlo Nike

    2015-09-15

    Coral reefs are degrading worldwide, but little information exists on their previous conditions for most regions of the world. Since 1989, we have been studying the Maldives, collecting data before, during and after the bleaching and mass mortality event of 1998. As early as 1999, many newly settled colonies were recorded. Recruits shifted from a dominance of massive and encrusting corals in the early stages of recolonisation towards a dominance of Acropora and Pocillopora by 2009. Coral cover, which dropped to less than 10% after the bleaching, returned to pre-bleaching values of around 50% by 2013. The 2004 tsunami had comparatively little effect. In 2014, the coral community was similar to that existing before the bleaching. According to descriptors and metrics adopted, recovery of Maldivian coral reefs took between 6 and 15years, or may even be considered unachieved, as there are species that had not come back yet.

  17. Ecology: Deep and complex ways to survive bleaching

    Science.gov (United States)

    Pandolfi, John M.

    2015-02-01

    Mass coral bleaching events can drive reefs from being the domains of corals to becoming dominated by seaweed. But longitudinal data show that more than half of the reefs studied rebound to their former glory. See Letter p.94

  18. Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

    Institute of Scientific and Technical Information of China (English)

    张永清; 谢晓芳; 黄少斌; 梁海云

    2014-01-01

    In the interest of accelerating aniline degradation, Fe2+and chelated Fe2+activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate (EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn’t follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

  19. Determination of anionic surface active agents using silica coated magnetite nanoparticles modified with cationic surfactant aggregates.

    Science.gov (United States)

    Pena-Pereira, Francisco; Duarte, Regina M B O; Trindade, Tito; Duarte, Armando C

    2013-07-19

    The development of a novel methodology for extraction and preconcentration of the most commonly used anionic surface active agents (SAAs), linear alkylbenzene sulfonates (LAS), is presented herein. The present method, based on the use of silica-magnetite nanoparticles modified with cationic surfactant aggregates, was developed for determination of C10-C13 LAS homologues. The proposed methodology allowed quantitative recoveries of C10-C13 LAS homologues by using a reduced amount of magnetic nanoparticles. Limits of detection were in the range 0.8-1.9μgL(-1) for C10-C13 LAS homologues, while the repeatability, expressed as relative standard deviation (RSD), ranged from 2.0 to 3.9% (N=6). Finally, the proposed method was successfully applied to the analysis of a variety of natural water samples.

  20. Quantitative structure-activity relationship study on some benzodiazepine derivatives as anti-Alzheimer agents.

    Science.gov (United States)

    Debnath, Bikash; Gayen, Shovanlal; Basu, Anindya; Srikanth, Kolluru; Jha, Tarun

    2004-12-01

    A QSAR study was performed in an attempt to explore the pharmacophore of some benzodiazepine derivatives as anti-Alzheimer agents for the inhibition of gamma-secretase. The study, which used the electrotopological state atom (ETSA) index, which encodes electronic and topological information, reveals the importance of two phenyl rings-one substituted and another unsubstituted, for the inhibition of the enzyme. Fluorine substitution on the substituted phenyl ring has an important contribution to the activity. R-configurations of the aliphatic chain substituents provide the exact conformation of the molecules to enter into the binding pockets of the receptor(s). [figure: see text]. General structure of benzodiazepine containing gamma-secretase inhibitors.

  1. SOFT MALLEABLE VESICLES TAILORED FOR ENHANCED DELIVERY OF ACTIVE AGENTS THROUGH THE SKIN: AN UPDATE

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar Parihar*, Mithun Bhowmick, Rajeev Kumar and Balkrishna Dubey

    2013-01-01

    Full Text Available Ethosomes are noninvasive delivery carriers that enable drugs to reach the deep skin layers and/or the systemic circulation. These are soft, malleable vesicles tailored for enhanced delivery of active agents. They are composed mainly of phospholipids, high concentration of ethanol and water. The high concentration of ethanol makes the ethosomes unique, as ethanol is known for its disturbance of skin lipid bilayer organization; therefore, when integrated into a vesicle membrane, it gives that vesicle the ability to penetrate the stratum corneum. Also, because of their high ethanol concentration, the lipid membrane is packed less tightly than conventional vesicles but has equivalent stability, allowing a more malleable structure and improves drug distribution ability in stratum corneum lipids. The Ethosomes were found to be suitable for various applications within the pharmaceutical, biotechnology, veterinary, cosmetic, and nutraceutical markets. These “soft vesicles” represents novel vesicular carrier for enhanced delivery to/through skin.

  2. BLEACHING OF SULFONATED CMP FROM BIO-TREATED WHEAT STRAW

    Institute of Scientific and Technical Information of China (English)

    HongYu; MenghuaQin; XuemeiLu; YinboQu; PeijiGao

    2004-01-01

    Wheat straw chemi-mechanical pulp was pretreated with a crude xylanase which was secreted by white rot fungus Phanerochaete Chrysosporium prior to hydrogen peroxide bleaching. The process of xylanase pretreatment and hydrogen peroxide bleaching was optimized. The xylanase treated pulp achieved a brightness gain of 5.8% ISO over the untreated pulp. The xylanase treatment was found to liberate reducing sugars and facilitating lignin removal. Fiber morphology of pulp treated with xylanase was also studied by SEM.

  3. Over-the-counter whitening agents: a concise review

    Directory of Open Access Journals (Sweden)

    Flávio Fernando Demarco

    2009-06-01

    Full Text Available Tooth discoloration is commonly found in the dental clinic and tooth bleaching has been considered the preferred esthetic alternative, being more conservative, safe and with predictable results. Supervised home-use of 10% Carbamide Peroxide (CP bleaching with custom-trays is the most common bleaching procedure dispensed by dentists to their patients. The good results obtained with this technique stimulated the flourishing of new products and techniques. Over-the-counter (OTC bleaching products appeared as a low-cost alternative to bleach discolored teeth without dentist supervision. Different OTC products are available in supermarkets, drug stores or on the Internet, including rinses, paint-on brushes, toothpastes, chewing guns, dental floss, and whitening strips. There is lack of clinical evidence regarding the safety and effectiveness of these products, being most of the studies supported by the manufacturers'. Basically, toothpastes, chewing gums, and dental floss are removal agents of superficial stains. Rinses and paint-on brushes with low levels of hydrogen peroxide have some whitening effect, but without clinical relevance. Strips present similar esthetic results and side-effects, compared to bleaching with 10% CP using trays; however, the studies have financial support from the manufacturers and were based on short term evaluations. Legislation varies widely in different countries regarding OTC dental bleaching. Concerns have appeared due to the potential abusive use of these self-medication agents, especially in young patients, with potential harmful results. Dentists should be acquainted with this kind of products to be able to inform their patients. In conclusion, there is a need for independent clinical trials to provide sufficient evidence regarding the use of OTC bleaching products.

  4. Towards Pro-active Embodied Agents: On the Importance of Neural Mechanisms Suitable to Process Time Information

    Science.gov (United States)

    de Croon, G.; Nolfi, S.; Postma, E. O.

    In Embodied Cognitive Science, many studies have focused on reactive agents, i.e. agents that have no internal state and always respond in the same way to the same stimulus. However, this particular focus is not due to a rejection of the importance of internal states. Rather, it is due to the difficulty of developing pro-active embodied and situated agents, that is agents able to: (a) extract internal states by integrating sensorymotor information through time and, (b) later use these internal states to modulate their motor behaviour according to the current environmental circumstances. In this chapter we will focus on how pro-active agents can be developed and, more specifically, on which are the neural mechanisms that might favour the development of pro-active agents. By comparing the results of five sets of evolutionary experiments in which simulated robots are provided with different types of recurrent neural networks, we gain insight into the relation between the robots` capabilities and the characteristics of their neural controllers. We show how special mechanisms for processing information in time facilitate the exploitation of internal states.

  5. Bitter melon extracts enhance the activity of chemotherapeutic agents through the modulation of multiple drug resistance.

    Science.gov (United States)

    Kwatra, Deep; Venugopal, Anand; Standing, David; Ponnurangam, Sivapriya; Dhar, Animesh; Mitra, Ashim; Anant, Shrikant

    2013-12-01

    Recently, we demonstrated that extracts of bitter melon (BME) can be used as a preventive/therapeutic agent in colon cancers. Here, we determined BME effects on anticancer activity and bioavailability of doxorubicin (DOX) in colon cancer cells. BME enhanced the effect of DOX on cell proliferation and sensitized the cells toward DOX upon pretreatment. Furthermore, there was both increased drug uptake and reduced drug efflux. We also observed a reduction in the expression of multidrug resistance conferring proteins (MDRCP) P-glycoprotein, MRP-2, and BCRP. Further BME suppressed DOX efflux in MDCK cells overexpressing the three efflux proteins individually, suggesting that BME is a potent inhibitor of MDR function. Next, we determined the effect of BME on PXR, a xenobiotic sensing nuclear receptor and a transcription factor that controls the expression of the three MDR genes. BME suppressed PXR promoter activity thereby suppressing its expression. Finally, we determined the effect of AMPK pathway on drug efflux because we have previously demonstrated that BME affects the pathway. However, inhibiting AMPK did not affect drug resistance, suggesting that BME may use different pathways for the anticancer and MDR modulating activities. Together, these results suggest that BME can enhance the bioavailability and efficacy of conventional chemotherapy.

  6. Transcriptomic responses to heat stress and bleaching in the elkhorn coral Acropora palmata

    KAUST Repository

    DeSalvo, MK

    2010-03-08

    The emergence of genomic tools for reef-building corals and symbiotic anemones comes at a time when alarming losses in coral cover are being observed worldwide. These tools hold great promise in elucidating novel and unforeseen cellular processes underlying the successful mutualism between corals and their dinoflagellate endosymbionts Symbiodinium spp. Since thermal stress triggers a breakdown in the symbiosis (coral bleaching), measuring the transcriptomic response to thermal stress-induced bleaching offers an extraordinary view of cellular processes that are specific to coral–algal symbioses. In the present study, we utilized a cDNA microarray containing 2059 genes of the threatened Caribbean elkhorn coral Acropora palmata to identify genes that are differentially expressed upon thermal stress. Fragments from replicate colonies were exposed to elevated temperature for 2 d, and samples were frozen for microarray analysis after 24 and 48 h. Totals of 204 and 104 genes were differentially expressed in samples that were collected 1 and 2 d after thermal stress, respectively. Analysis of the differentially expressed genes indicates a cellular stress response in A. palmata involving (1) growth arrest, (2) chaperone activity, (3) nucleic acid stabilization and repair, and (4) removal of damaged macromolecules. Other differentially expressed processes include sensory perception, metabolite transfer between host and endosymbiont, nitric oxide signaling, and modifications to the actin cytoskeleton and extracellular matrix. The results are compared with those from a previous coral microarray study of thermal stress in Montastraea faveolata, and point to an overall evolutionary conserved bleaching response in scleractinian corals.

  7. HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    Yumeng Zhao; Shuhui Yang; Liang Sheng; Yonghao Ni

    2004-01-01

    Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.

  8. Research on Bleaching Process for Cork Material%软木材料漂白工艺的研究

    Institute of Scientific and Technical Information of China (English)

    常宇婷; 雷亚芳; 张丽丛

    2009-01-01

    结合软木材料的特点,分析研究漂白剂的性能,选取过氧化氢(H_20_2)作为软木材料的漂白剂;采用SC-80C全自动色差计对漂白试样进行白度的定量测量,综合考虑定性观察和定量检测的结果,确定软木材料的最佳漂白工艺条件为:过氧化氢浓度为9%,漂白时间为60 min,漂白温度为70℃,漂白液的pH值为10.以白度为评价指标,各因素对漂白效果影响的程度从大到小依次为:温度,时间,过氧化氢浓度,pH值.各因素对白度的影响都很显著.%According to the characteristic of the cork material, analyzing and researching the property of va-rious bleaching agents and choosing H_2O_2 as bleaching agents for cork material bleaching, and using full-auto-matic chromatic aberration meter of SC-80C to quantitively gauge the chromatic aberration and whiteness of bleached sample. On the basis of considering the result of qualitative observation and quantitative determina-tion, the best bleaching process conditions for cork material are obtained as follows: H_2O_2 concentration of 9%, heating time of 60 min, temperature of 70℃ and pH value of 10. Influence of all above mentioned fac-tors is of markedness, and the arrangement in order of the factors affecting the whiteness of bleached sample isas follows: temperature, time, concentration of H_2O_2 and pH (from big to small).

  9. 筒子纱短流程快速漂染工艺%Rapid bleaching and dyeing of cheese

    Institute of Scientific and Technical Information of China (English)

    陈荣平

    2011-01-01

    Through the use of multi-functional rapid oxygen bleaching agent BLG, as well as adding alkali in dyeing bath and enzyme soaping, the rapid oxygen bleaching and dyeing process of cheese are achieved, and the whole process time is shortened 1/3. The process features energy saving and reduced discharge, low damage to fiber, good reproducibility, high quality and low cost.%通过采用多功能快速氧漂助剂BLG,以及预加碱染色和皂洗酶水洗后处理,实现了筒子纱的快速氧漂和染色生产,使筒子纱漂染全程的工艺时间缩短1/3.该工艺节能减排,对纤维损伤小,生产重现性好,提高了产品质量,降低了生产成本.

  10. New heterocycles having double characters; as antimicrobial and surface active agents.

    Directory of Open Access Journals (Sweden)

    El-Sayed, R.

    2004-12-01

    Full Text Available Fatty acids isothiocyanate (1 was used as a starting material to synthesize some important heterocycles such as triazoles, oxazoles, thiazoles, benzoxazoles and quinazolines by treating with different types of nucleophiles such as nitrogen nucleophiles, oxygen nucleophiles, and sulfur nucleophiles. The produced compounds were subjected to propylene oxide in different moles (n = 3, 5 and 7 to produce novel groups of nonionic compounds having the double function as antimicrobial and surface active agents which can be used in the manufacturing of drugs, cosmetics, pesticides or can be used as antibacterial and/or antifungal. The physical properties as surface and interfacial tension, cloud point, foaming height, wetting time, emulsification power and the critical micelle concentration (CMC were determined, antimicrobial and biodegradability were also determined.Isocianatos de acidos grasos se utilizaron como material de partida para la síntesis de importantes heterociclos tales como triazoles, oxazoles, thoazoles, benzoxazoles y quinazolinas mediante el tratamiento de los mismos con diferentes tipos de nucleofilos tales como nucleofilos nitrogenados, oxigenados, o azufrados. Los compuestos producidos se trataron con oxido de propileno a diferentes concentraciones molares (n = 3, 5 y 7 para producir nuevos grupos de compuestos no iónicos que tuvieran la doble función de ser compuestos antimicrobianos y agentes de superficie, que se pudieran usar en la fabricación de medicinas, cosméticos, pesticidas o como antibacterianos o antifúngicos. Se determinaron sus propiedades tales como tensión superficial e interfacial, punto de turbidez, altura de espuma, tiempo de mojado, poder de emulsificación y concentración micelar crítica (CMC, asi como sus propiedades antimicrobianas y de degradabilidad.

  11. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    Energy Technology Data Exchange (ETDEWEB)

    Asmis, Lars [Institute for Clinical Hematology, University Hospital Zuerich, Zuerich (Switzerland); Tanner, Felix C. [Cardiovascular Research, Physiology Institute, University of Zuerich, Zuerich (Switzerland); Center for Integrative Human Physiology, University of Zuerich, Zuerich (Switzerland); Cardiology, Cardiovascular Center, University Hospital Zuerich, Zuerich (Switzerland); Sudano, Isabella [Cardiology, Cardiovascular Center, University Hospital Zuerich, Zuerich (Switzerland); Luescher, Thomas F. [Cardiovascular Research, Physiology Institute, University of Zuerich, Zuerich (Switzerland); Center for Integrative Human Physiology, University of Zuerich, Zuerich (Switzerland); Cardiology, Cardiovascular Center, University Hospital Zuerich, Zuerich (Switzerland); Camici, Giovanni G., E-mail: giovannic@access.uzh.ch [Cardiovascular Research, Physiology Institute, University of Zuerich, Zuerich (Switzerland); Center for Integrative Human Physiology, University of Zuerich, Zuerich (Switzerland)

    2010-01-22

    Background: DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Methods and results: Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysis showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54 {+-} 0.9427%, n = 5, P < 0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0% {+-} 4.031, n = 9, P = 0.0004 versus control) as well as a decreased maximal aggregation (-6.388 {+-} 2.212%, n = 6, P = 0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Conclusions: Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents.

  12. Comparative in vitro activity of oritavancin and other agents against methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Sweeney, Debora; Shinabarger, Dean L; Arhin, Francis F; Belley, Adam; Moeck, Greg; Pillar, Chris M

    2017-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections constitute a threat to the public health due to their prevalence and associated mortality and morbidity. Several agents have been recently approved to treat MRSA skin infections including lipoglycopeptides (dalbavancin, oritavancin, and telavancin), ceftaroline, and tedizolid. This study compared the MIC, minimum bactericidal concentration (MBC), and time-kill of these agents alongside daptomycin, linezolid, and vancomycin against MRSA (n=15); meropenem, cefazolin, and nafcillin were also included against methicillin-susceptible S. aureus (MSSA [n=12]). MIC and MBC testing was conducted in accordance with Clinical and Laboratory Standards Institute guidelines, and time-kills were evaluated at multiples of the MIC and the free-drug maximum plasma concentration (fCmax) at both standard and high inoculum densities for a subset of MRSA (n=2) and MSSA (n=2). MRSA and MSSA were highly susceptible to all agents, with the lipoglycopeptides having the most potent activity by MIC50/90. All agents excluding tedizolid and linezolid were bactericidal by MBC for MRSA and MSSA, though dalbavancin and telavancin exhibited strain-specific bactericidal activity for MRSA. All agents excluding tedizolid and linezolid were bactericidal by time-kill at their respective fCmax against MRSA and MSSA at standard inoculum density, though oritavancin exhibited the most rapid bactericidal activity. Oritavancin and daptomycin at their respective fCmax maintained similar kill curves at high inoculum density. In contrast, the killing observed with other agents was typically reduced or slowed at high inoculum density. These data demonstrate the rapid bactericidal activity of oritavancin and daptomycin against S. aureus relative to other MRSA agents regardless of bacterial burden.

  13. Enhancing activated-peroxide formulations for porous materials: Test methods and results

    Energy Technology Data Exchange (ETDEWEB)

    Krauter, Paula [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tucker, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tezak, Matthew S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boucher, Raymond [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-12-01

    During an urban wide-area incident involving the release of a biological warfare agent, the recovery/restoration effort will require extensive resources and will tax the current capabilities of the government and private contractors. In fact, resources may be so limited that decontamination by facility owners/occupants may become necessary and a simple decontamination process and material should be available for this use. One potential process for use by facility owners/occupants would be a liquid sporicidal decontaminant, such as pHamended bleach or activated-peroxide, and simple application devices. While pH-amended bleach is currently the recommended low-tech decontamination solution, a less corrosive and toxic decontaminant is desirable. The objective of this project is to provide an operational assessment of an alternative to chlorine bleach for low-tech decontamination applications activated hydrogen peroxide. This report provides the methods and results for activatedperoxide evaluation experiments. The results suggest that the efficacy of an activated-peroxide decontaminant is similar to pH-amended bleach on many common materials.

  14. Removal of the organic content from a bleached kraft pulp mill effluent by a treatment with silica-alginate-fungi biocomposites.

    Science.gov (United States)

    Duarte, Katia; Justino, Celine I L; Pereira, Ruth; Panteleitchouk, Teresa S L; Freitas, Ana C; Rocha-Santos, Teresa A P; Duarte, Armando C

    2013-01-01

    This study attempts a treatment strategy of a bleached kraft pulp mill effluent with Rhizopus oryzae or Pleurotus sajor caju encapsulated on silica-alginate (biocomposite of silica-alginate-fungi, with the purpose of reducing its potential impact in the environment. Active (alive) or inactive (death by sterilization) Rhizopus oryzae or Pleurotus sajor caju was encapsulated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the bleached kraft pulp mill effluent. The treatment of bleached kraft pulp mill effluent by active and inactive biocomposites was performed throughout 29 days at 28°C. The efficiency of treatment was evaluated by measuring the removal of organic compounds, chemical oxygen demand and the relative absorbance ratio over time. Both fungi species showed potential for removal of organic compounds, colour and chemical oxygen demand. Maximum values of reduction in terms of colour (56%), chemical oxygen demand (65%) and organic compounds (72-79%) were attained after 29 days of treatment of bleached kraft pulp mill effluent by active Rhizopus oryzae biocomposites. The immobilization of fungi, the need for low fungal biomass, and the possibility of reutlization of the biocomposites clearly demonstrate the industrial and environmental interest in bleached kraft pulp mill effluent treatment by silica-alginate-fungi biocomposites.

  15. Effects of different bulking agents on the maturity, enzymatic activity, and microbial community functional diversity of kitchen waste compost.

    Science.gov (United States)

    Wang, Xiaojuan; Zhang, Wenwei; Gu, Jie; Gao, Hua; Qin, Qingjun

    2016-10-01

    Aerobic composting is an effective method for the disposal and utilization of kitchen waste. However, the addition of a bulking agent is necessary during kitchen waste composting because of its high moisture content and low C/N ratio. In order to select a suitable bulking agent, we investigated the influence of leaf litter (LL), sawdust (SD), and wheat straw (WS) on the enzymatic activity, microbial community functional diversity, and maturity indices during the kitchen waste composting process. The results showed that the addition of WS yielded the highest maturity (the C/N ratio decreased from 25 to 13, T value = 0.5, and germination index (GI) = 114.7%), whereas the compost containing SD as a bulking agent had the lowest maturity (GI = 32.4%). The maximum cellulase and urease activities were observed with the WS treatment on day 8, whereas the SD treatment had the lowest cellulase activity and the LL treatment had the lowest urease activity. The compost temperature and microbial activity (as the average well color development) showed that bulking the composts with SD prolonged the composting process. The diversity index based on the community-level physiological profile showed that the composts bulked with LL and WS had greater microbial community functional diversity compared with those bulked with SD. Thus, the maturity indexes and enzymatic activities suggest that WS is a suitable bulking agent for use in kitchen waste composting systems.

  16. Determination of burial dose in incompletely bleached fluvial samples using single grains of quartz

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Murray, A.S.; Bøtter-Jensen, Lars

    2007-01-01

    We determine the burial dose in three known-age incompletely bleached fluvial samples using single grains of quartz. Estimation of burial dose in incompletely bleached samples requires that the characteristics of the well-bleached part of the distribution are known in order to distinguish between...... well-bleached and poorly bleached grains. It is especially important to investigate if the uncertainties assigned to individual estimates of dose adequately describe the observed variability in well-bleached dose distributions. We investigate this by quantifying the overdispersion in laboratory...

  17. In vitro activities of new and conventional antifungal agents against clinical Scedosporium isolates.

    Science.gov (United States)

    Meletiadis, Joseph; Meis, Jacques F G M; Mouton, Johan W; Rodriquez-Tudela, Juan Luis; Donnelly, J Peter; Verweij, Paul E

    2002-01-01

    The susceptibilities of 13 clinical isolates of Scedosporium apiospermum and 55 clinical isolates of S. prolificans to new and conventional drugs belonging to three different classes of antifungal agents, the azoles (miconazole, itraconazole, voriconazole, UR-9825, posaconazole), the polyenes (amphotericin B, nystatin and liposomal nystatin), and allylamines (terbinafine), were studied by use of proposed standard M38-P of NCCLS. Low growth-inhibitory antifungal activities were found in vitro for most of the drugs tested against S. prolificans isolates, with the MICs at which 90% of isolates are inhibited (MIC(90)s) being >8 microg/ml; the MIC(90)s of voriconazole and UR-9825, however, were 4 microg/ml. S. apiospermum isolates were more susceptible in vitro, with the highest activity exhibited by voriconazole (MIC(90)s, 0.5 microg/ml), followed by miconazole (MIC(90)s, 1 microg/ml), UR-9825 and posaconazole (MIC(90)s, 2 microg/ml), and itraconazole (MIC(90)s, 4 microg/ml). The MICs of terbinafine, amphotericin B, and the two formulations of nystatin (for which no statistically significant differences in antifungal activities were found for the two species) for S. apiospermum isolates were high. Cross-resistance was observed among all the azoles except posaconazole and among all the polyenes except the lipid formulation. A distribution analysis was performed with the MICs of each drug and for each species. Bimodal and skewed MIC distributions were obtained, and cutoffs indicating the borders of different MIC subpopulations of the distributions were determined on the basis of the normal plot technique. These cutoffs were in many cases reproducible between 48 and 72 h.

  18. Significant antitumor activity in vivo following treatment with the microtubule agent ENMD-1198.

    Science.gov (United States)

    LaVallee, Theresa M; Burke, Patricia A; Swartz, Glenn M; Hamel, Ernest; Agoston, Gregory E; Shah, Jamshed; Suwandi, Lita; Hanson, Art D; Fogler, William E; Sidor, Carolyn F; Treston, Anthony M

    2008-06-01

    Clinical studies using the microtubule-targeting agent 2-methoxyestradiol (2ME2; Panzem) in cancer patients show that treatment is associated with clinical benefit, including prolonged stable disease, complete and partial responses, and an excellent safety profile. Studies have shown that 2ME2 is metabolized by conjugation at positions 3 and 17 and oxidation at position 17. To define structure-activity relationships for these positions of 2ME2 and to generate metabolically stable analogues with improved anti-tubulin properties, a series of analogues was generated and three lead analogues were selected, ENMD-1198, ENMD-1200, and ENMD-1237. These molecules showed improved metabolic stability with >65% remaining after 2-h incubation with hepatocytes. Pharmacokinetic studies showed that oral administration of the compounds resulted in increased plasma levels compared with 2ME2. All three analogues bind the colchicine binding site of tubulin, induce G(2)-M cell cycle arrest and apoptosis, and reduce hypoxia-inducible factor-1alpha levels. ENMD-1198 and ENMD-1200 showed improved in vitro antiproliferative activities. Significant reductions in tumor volumes compared with vehicle-treated mice were observed in an orthotopic breast carcinoma (MDA-MB-231) xenograft model following daily oral treatment with all compounds (ANOVA, P < 0.05). Significantly improved median survival time was observed with ENMD-1198 and ENMD-1237 (200 mg/kg/d) in a Lewis lung carcinoma metastatic model (P < 0.05). In both tumor models, the high-dose group of ENMD-1198 showed antitumor activity equivalent to that of cyclophosphamide. ENMD-1198 was selected as the lead molecule in this analogue series and is currently in a phase I clinical trial in patients with refractory solid tumors.

  19. Constructive interactions among nutrients and bone-active pharmacologic agents with principal emphasis on calcium, phosphorus, vitamin D and protein.

    Science.gov (United States)

    Heaney, R P

    2001-10-01

    Current and emerging bone active pharmacologic agents are capable of producing substantial gains in bone mass. However, nutrition must be adequate if this potential is to be realized. Calcium and vitamin D supplementation, for example, have both been demonstrated to augment substantially the skeletal response to estrogen therapy in postmenopausal women. The bisphosphonates and selective estrogen receptor modulator (SERMs) have all been tested only in the context of supplemental calcium and vitamin D. Therefore, it cannot be assumed that these bone active agents would be effective in the absence of these nutrients. Adequate protein intake has also been demonstrated to protect bone mass in the elderly and to improve recovery from osteoporotic fractures. Phosphorus intake, less extensively studied, may be more important than currently recognized, particularly in elderly individuals living alone, eating little meat, and receiving anti-osteoporosis treatment agents.

  20. Porcelain laminate veneer restorations bonded with a three-liquid silane bonding agent and a dual-activated luting composite.

    Science.gov (United States)

    Matsumura, Hideo; Aida, Yukiko; Ishikawa, Yumi; Tanoue, Naomi

    2006-12-01

    This clinical report describes the fabrication and bonding of porcelain laminate veneer restorations in a patient with anterior open spaces. Laminate veneer restorations made of feldspathic porcelain were etched with 5% hydrofluoric acid, rinsed under tap water, ultrasonically cleaned with methanol, and primed with a chemically activated three-liquid silane bonding agent (Clearfil Porcelain Bond). The enamel surfaces were etched with 40% phosphoric acid, rinsed with water, and primed with a two-liquid bonding agent (Clearfil New Bond) that contained a hydrophobic phosphate (10-methacryloyloxydecyl dihydrogen phosphate; MDP). The restorations were bonded with a dual-activated luting composite (Clapearl DC). The veneers have been functioning satisfactorily for an observation period of one year. Combined use of the Clearfil bonding agents and Clapearl DC luting composite is an alternative to conventional materials for seating porcelain laminate veneer restorations, although the system is inapplicable to dentin bonding.

  1. [Ajoene the main active compound of garlic (Allium sativum): a new antifungal agent].

    Science.gov (United States)

    Ledezma, Eliades; Apitz-Castro, Rafael

    2006-06-01

    The curative properties of garlic in medicine have been known for a long time. But, it was only in the last three decades when garlic properties were seriously investigated confirming its potential as therapeutic agent. Allicin, ajoene, thiosulfinates and a wide range of other organosulphurate compounds, are known to be the constituents linked to the garlic properties. Regarding the biochemical properties of these compounds, ajoene [(E,Z)-4,5,9 Trithiadodeca 1,6,11 Triene 9-oxide] is stable in water, and it can be obtained by chemical synthesis. There is evidence that some of the garlic constituents exert a wide variety of effects on different biological systems. However, ajoene is the garlic compound related to more biological activities, as showed in in vitro and in vivo systems. Those studies found that ajoene has antithrombotic, anti-tumoral,antifungal, and antiparasitic effects. This study deals with a recently described antifungal property of ajoene, and its potential use in clinical trails to treat several fungal infections.

  2. Simultaneous two-photon activation of type-I photodynamic therapy agents.

    Science.gov (United States)

    Fisher, W G; Partridge, W P; Dees, C; Wachter, E A

    1997-08-01

    The excitation and emission properties of several psoralen derivatives are compared using conventional single-photon excitation and simultaneous two-photon excitation (TPE). Two-photon excitation is effected using the output of a mode-locked titanium: sapphire laser, the near infrared output of which is used to promote nonresonant TPE directly. Specifically, the excitation spectra and excited-state properties of 8-methoxypsoralen and 4'-aminomethyl-4,5,8-trimethylpsoralen are shown to be equivalent using both modes of excitation. Further, in vitro feasibility of two-photon photodynamic therapy (PDT) is demonstrated using Salmonella typhimurium. Two-photon excitation may be beneficial in the practice of PDT because it would allow replacement of visible or UV excitation light with highly penetrating, nondamaging near infrared light and could provide a means for improving localization of therapy. Comparison of possible laser excitation sources for PDT reveals the titanium: sapphire laser to be exceptionally well suited for nonlinear excitation of PDT agents in biological systems due to its extremely short pulse width and high repetition rate that together provide efficient PDT activation and greatly reduced potential for biological damage.

  3. In-vitro activity of 21 antimicrobial agents against Neisseria gonorrhoeae in Brussels.

    Science.gov (United States)

    Gordts, B; Vanhoof, R; Hubrechts, J M; Dierickx, R; Coignau, H; Butzler, J P

    1982-02-01

    The minimum inhibitory concentrations (MIC) of 21 antimicrobial agents was measured for 80 strains of Neisseria gonorrhoeae isolated in Brussels in 1978. Bimodal distributions were found for penicillin G, ampicillin, amoxycillin, carbenicillin, and cephalexin. Of the strains, 17.5% were relatively resistant to penicillin G (MIC greater than 0.08 microgram/ml) 27.5% to ampicillin (MIC greater than 0.16 microgram/ml), 23.8% to amoxycillin, and 43.3% to carbenicillin. Cefotaxime was the most active antibiotic, with MICs in the nanogram range; 3.8% and 5% of the strains were relatively resistant to cephaloridine and cephalexin respectively, but no strains were resistant to cefazolin, cefuroxime, or cefotaxime. Resistance to tetracycline, doxycycline, minocycline, erythromycin, and spiramycin (MIC greater than 1 microgram/ml) was found in 6.3%, 2.5%, 5%, and 51.3% of the strains respectively. A very good correlation was present between chloramphenicol and thiamphenicol, with 16.3% and 10% of relatively resistant strains respectively. Only two isolates showed an MIC greater than 1.25 microgram/ml for rifampicin, and 10% of the strains needed greater than or equal to 12 microgram/ml of spectinomycin for complete inhibition of growth. A very high energy was found for the 20 : 1 combination of sulphamethoxazole and trimethoprim, with only one isolate resistant to this combination. None of the strains tested produced beta-lactamase.

  4. In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

    Science.gov (United States)

    2009-01-01

    Background The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16) strain in two mouse wound models. Results Following irradiation of wounds with 360 J/cm2 of laser light (670 nm) in the presence of 100 μg/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT)-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours. Conclusion The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites. PMID:19193212

  5. In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

    Directory of Open Access Journals (Sweden)

    Bennett Jon

    2009-02-01

    Full Text Available Abstract Background The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16 strain in two mouse wound models. Results Following irradiation of wounds with 360 J/cm2 of laser light (670 nm in the presence of 100 μg/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours. Conclusion The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites.

  6. Use of the Crohn's disease activity index in clinical trials of biological agents

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Crohn's disease activity index (CDAI) has been commonly used to assess the effects of treatment with different agents in Crohn's disease (CD). However, these studies may be compromised, if the results compared to a placebo or standard therapy group (in the absence of a placebo) substantially differ from the expected response. In addition, significant concerns have been raised regarding the reliability and validity of the CDAI. Reproducibility of the CDAI may be limited as significant inter-observer error has been recorded, even if measurements are done by experienced clinicians with expertise in the diagnosis and treatment of CD. Finally, many CDAI endpoints are open to subjective interpretation and have the potential for manipulation. This is worrisome as there is the potential for significant financial gain, if the results of a clinical trial appear to provide a positive result. Physicians caring for patients should be concerned about the positive results in clinical trials that are sponsored by industry, even if the trials involve respected centers and the results appear in highly ranked medical journals.

  7. Bacteria associated with the bleached and cave coral Oculina patagonica.

    Science.gov (United States)

    Koren, Omry; Rosenberg, Eugene

    2008-04-01

    The relative abundance of bacteria in the mucus and tissues of Oculina patagonica taken from bleached and cave (azooxanthellae) corals was determined by analyses of the 16S rRNA genes from cloned libraries of extracted DNA and from isolated colonies. The results were compared to previously published data on healthy O. patagonica. The bacterial community of bleached, cave, and healthy corals were completely different from each other. A tight cluster (>99.5% identity) of bacteria, showing 100% identity to Acinetobacter species, dominated bleached corals, comprising 25% of the 316 clones sequenced. The dominant bacterial cluster found in cave corals, representing 29% of the 97 clones sequenced, showed 98% identity to an uncultured bacterium from the Great Barrier Reef. Vibrio splendidus was the most dominant species in healthy O. patagonica. The culturable bacteria represented 0.1-1.0% of the total bacteria (SYBR Gold staining) of the corals. The most abundant culturable bacteria in bleached, cave, and healthy corals were clusters that most closely matched Microbulbifer sp., an alpha-proteobacterium previously isolated from healthy corals and an alpha-protobacterium (AB026194), respectively. Three generalizations emerge from this study on O. patagonica: (1) More bacteria are associated with coral tissue than mucus; (2) tissue and mucus populations are different; (3) bacterial populations associated with corals change dramatically when corals lack their symbiotic zooxanthellae, either as a result of the bleaching disease or when growing in the absence of light.

  8. Coral Reef Bleaching at Agatti Island of Lakshadweep Atolls, India

    Institute of Scientific and Technical Information of China (English)

    Ramar Vinoth; Mohan Gopi; Thipramalai Thankappanpillai Ajith Kumar; Thirunavukarassu Thangaradjou; Thangavel Balasubramanian

    2012-01-01

    A survey on coral bleaching was carried out at Agatti Island of Lakshadweep from May to June 2010.Elevated sea surface temperatures (SSTs) of the region exceeded the seasonal average and delayed the onset of monsoon,which triggered widespread bleaching of corals.The Agatti reefs showed an average of 73% bleached corals with apparent bleaching-related mortality of sea anemones (87%) and giant clams (83%).The SST increased up to 34 ℃ with an average maximum SST of 32.5℃ during the study period between May and June 2010.Coral reefs on the southern side of the island are fully or partially exposed to sun light during low tide in contrast to the other side.This suggests that the mortality is more likely due to the low tide exposure than exclusively due to the elevated SST.Observations indicated a clear increase in coral bleaching during April 2010,at levels higher than that in normal summer.

  9. Curcumin derivatives as metal-chelating agents with potential multifunctional activity for pharmaceutical applications.

    Science.gov (United States)

    Ferrari, Erika; Benassi, Rois; Sacchi, Stefania; Pignedoli, Francesca; Asti, Mattia; Saladini, Monica

    2014-10-01

    Curcuminoids represent new perspectives for the development of novel therapeutics for Alzheimer's disease (AD), one probable mechanism of action is related to their metal complexing ability. In this work we examined the metal complexing ability of substituted curcuminoids to propose new chelating molecules with biological properties comparable with curcumin but with improved stability as new potential AD therapeutic agents. The K2T derivatives originate from the insertion of a -CH2COOC(CH3)3 group on the central atom of the diketonic moiety of curcumin. They retain the diketo-ketoenol tautomerism which is solvent dependent. In aqueous solution the prevalent form is the diketo one but the addition of metal ion (Ga(3+), Cu(2+)) causes the dissociation of the enolic proton creating chelate complexes and shifting the tautomeric equilibrium towards the keto-enol form. The formation of metal complexes is followed by both NMR and UV-vis spectroscopy. The density functional theory (DFT) calculations on K2T21 complexes with Ga(3+) and Cu(2+) are performed and compared with those on curcumin complexes. [Ga(K2T21)2(H2O)2](+) was found more stable than curcumin one. Good agreement is detected between calculated and experimental (1)H and (13)C NMR data. The calculated OH bond dissociation energy (BDE) and the OH proton dissociation enthalpy (PDE), allowed to predict the radical scavenging ability of the metal ion complexed with K2T21, while the calculated electronic affinity (EA) and ionization potential (IP) represent yardsticks of antioxidant properties. Eventually theoretical calculations suggest that the proton-transfer-associated superoxide-scavenging activity is enhanced after binding metal ions, and that Ga(3+) complexes display possible superoxide dismutase (SOD)-like activity.

  10. Effect of Green Tea Extract as Antioxidant on Shear Bond Strength of Resin Composite to in-Office and Home-Bleached Enamel

    Directory of Open Access Journals (Sweden)

    Sharafeddin F

    2016-09-01

    Full Text Available Statement of Problem: Shear bond strength (SBS of home and office bleached enamel will be compromised by immediate application of composite restoration. Antioxidant agent may overcome this problem. Objectives: This in vitro study assessed the effect of green tea extract on shear bond strength of resin composite to in-office and home-bleached enamel. Materials and Methods: In this experimental study, 40 extracted intact human incisors were embedded in cylindrical acrylic resin blocks (2.5 ×1.5 cm, with the coronal portion above the cemento enamel junction out of the block. Then, after bleaching labial enamel surfaces of 20 teeth with 15% carbamide peroxide 6 hours a day for 5 days, they were randomly divided into two groups: A1 and A2 (n = 10, depending upon whether or not they are treated with antioxidant. Labial enamel surfaces of the remaining 20 teeth were bleached with 38% hydrogen peroxide before being randomly divided into groups B1 and B2 (n = 10, again depending on whether or not the antioxidant was used in their treatment . The experimental groups (A2,B2 were treated with 5% solution of green tea extract before resin composite restoration was done by a cylindrical Teflon mould (5×2 mm. Shear bond strength of the specimens was tested under a universal testing machine (Zwick/Roell Z020. The SBS data were analyzed by using One-way ANOVA and Tukey HSD tests (p < 0.05. Results: There were no statistically significant differences between shear bond strength of the control group (A1 and treated group (A2 but there were statistically significant differences between the groups B1 and B2 (p < 0.05. Conclusions: Application of antioxidant did not increase the shear bond strength of home-bleached enamel to resin composite but its application increased the shear bond strength of in-office bleached enamel to resin composite.

  11. An Active Networks Architecture Based on Mobile Agent%一种基于移动Agent的主动网络体系结构

    Institute of Scientific and Technical Information of China (English)

    张君雁; 闵帆; 杨国纬

    2003-01-01

    This paper proposes an active networks architecture which supports both integrated and discrete operationmodel based on mobile Agent technology. Mobile Agent is the component for customized function transferring, activenode provides software application layer, and Agent server processes mobile Agent specific customization. For devel-opment and deployment of specific application protocol, this paper also proposes an abstract protocol framework and aprotocol loading mechanism to enhance network performance.

  12. C5-Modified nucleosides exhibiting anticancer activity.

    Science.gov (United States)

    Lee, Yoon-Suk; Park, Sun Min; Kim, Hwan Mook; Park, Song-Kyu; Lee, Kiho; Lee, Chang Woo; Kim, Byeang Hyean

    2009-08-15

    We describe (i) a simple method for the synthesis of C5-modified nucleosides from 5-iodo-2'-deoxyuridine and (ii) their activity against six types of human cancer cell lines (HCT15, MM231, NCI-H23, NUGC-3, PC-3, ACHN). We generated nitrile oxides in situ from oximes using a commercial bleaching agent; their cycloadditions with 5-ethynyl-2'-deoxyuridine yielded isoxazole derivatives possessing activity against the cancer cell lines. We synthesized several azides from benzylic bromides and their click reactions with 5-ethynyl-2'-deoxyuridine provided triazole derivatives.

  13. Cytotoxic effects of five commonly abused skin toning (bleaching) creams on Allium cepa root tip mitosis.

    Science.gov (United States)

    Udengwu, O S; Chukwujekwu, J C

    2008-09-15

    The Allium test was used to study the cytotoxic effects of five commonly abused skin toning creams--Ikb, Tura, Top gel, Dorot and Mililo. These creams are commonly used by some black skinned people (especially the females) as skin lightening (bleaching) agents. The results showed that all the five bleaching creams were mito-depressive in action. They exhibited both chromatoclassic and mitoclassic effects. Their depressive effects were found to increase with duration of treatment. The induced abnormalities included chromosome contraction, spindle breakages, c-metaphase, star anaphase, chromosome stickiness and sticky bridges, precocious chromosome movement as well as endomitosis. It is suggested that since all eukaryotic cells are basically the same, these observed abnormalities could be similar to the effects these chemicals have on human skin when they are applied. Some of these are known to cause alteration in melanin formation as well as the biosynthesis of the enzyme tyrosinase. Furthermore, since certain points on the chromosomes called fragile sites have been implicated in oncogenesis, the observed abnormalities may be part of (or include) the switching on mechanisms of such genes, which could be responsible for the transformation of normal skin cells to malignant cells in those who abuse these creams.

  14. Catalase and sodium fluoride mediated rehabilitation of enamel bleached with 37% hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Ruchi Thakur

    2015-01-01

    Full Text Available Background: Bleaching agents bring about a range of unwanted changes in the physical structure of enamel which needs to be restored qualitatively and timely. Catalase being an antioxidant ensures the effective removal of free radicals and improvement in fluoride mediated remineralization from the enamel microstructure which if retained may harm the integrity and affect the hardness of enamel. Materials and Methods: Thirty freshly extracted incisors were sectioned to 6 slabs which were divided into 5 groups: Group A, control; Group B, treatment with 37% hydrogen peroxide (HP; Group C, treatment with 37% HP and catalase, Group D, treatment with 37% HP and 5% sodium fluoride application, Group E, treatment with 37% HP followed by catalase and 5% sodium fluoride. Scanning electron microscope and microhardness analysis were done for all slabs. One-way ANOVA test was applied among different groups. Results: Vicker′s microhardness number (VHN of Group B and C was significantly lower. No significant difference between VHN of Group B and C. VHN of Group D was significantly higher than Group A, B, and C; but significantly lower than Group E. VHN of Group E was significantly higher than any other experimental group. One-way ANOVA revealed a highly significant P value (P = 0.0001 and so Tukey′s post-hoc Test for the group comparisons was employed. Conclusion: Subsequent treatment of bleached enamel with catalase and fluoride varnish separately results in repairing and significantly increasing the microhardness.

  15. Covalent binding of the organophosphorus agent FP-biotin to tyrosine in eight proteins that have no active site serine

    OpenAIRE

    Grigoryan, Hasmik; Li, Bin; Anderson, Erica K.; Xue, Weihua; Nachon, Florian; Lockridge, Oksana; Schopfer, Lawrence M.

    2009-01-01

    Organophosphorus esters (OP) are known to bind covalently to the active site serine of enzymes in the serine hydrolase family. It was a surprise to find that proteins with no active site serine are also covalently modified by OP. The binding site in albumin, transferrin, and tubulin was identified as tyrosine. The goal of the present work was to determine whether binding to tyrosine is a general phenomenon. Fourteen proteins were treated with a biotin-tagged organophosphorus agent called FP-b...

  16. Novel N-(pyrimidin-4-ylthiazol-2-amine derivatives as dual-action hypoglycemic agents that activate GK and PPARγ

    Directory of Open Access Journals (Sweden)

    Hui-peng Song

    2011-10-01

    Full Text Available A series of novel N-(pyrimidin-4-ylthiazol-2-amine derivatives have been synthesized and evaluated as glucokinase (GK activators. Ethyl 2-(6-(4-(2-hydroxyethylpiperazin-1-yl-2-methylpyrimidin-4-yl-aminothiazole-5-carboxylate was found to be a potent dual-acting hypoglycemic agent activating both GK and PPARγ. When given orally to normal mice, the compound demonstrated significant efficacy in decreasing the glucose level after oral glucose loading.

  17. Bleaching of red lake paints in encaustic mummy portraits

    Science.gov (United States)

    Miliani, Costanza; Daveri, Alessia; Spaabaek, Lin; Romani, Aldo; Manuali, Valentina; Sgamellotti, Antonio; Brunetti, Brunetto Giovanni

    2010-09-01

    The present paper reports on the study of the development of whitish opacity in pink paints in encaustic mummy portraits. Non-invasive measurements carried out on two encaustic portraits belonging to the Ny Carlsberg Glyptotek, Copenhagen, by reflectance FTIR and UV-vis fluorescence have shown that the areas prone to the bleaching phenomenon had been painted with melted beeswax and an anthraquinone vegetal lake mixed with calcium sulphate hemihydrate and dihydrate. The hypothesis that the bleaching disease was neither related to a degradation of the dyes nor to an alteration of the wax but rather to a dehydration-hydration reaction of the CaSO4-H2O system, has been corroborated by the analyses of two microsamples from the bleached areas and ascertained by accelerated ageing experiments on encaustic models.

  18. SUGARCANE BAGASSE PULPING AND BLEACHING: THERMAL AND CHEMICAL CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Fernandes Pereira

    2011-05-01

    Full Text Available Cellulose fibers were isolated from sugarcane bagasse in three stages. Initially sugarcane bagasse was subjected to a pre-treatment process with hydrolyzed acid to eliminate hemicellulose. Whole cellulosic fibers thus obtained were then subjected to a two-stage delignification process and finally to a bleaching process. The chemical structure of the resulting cellulose fibers was studied by Fourier Transform Infrared (FTIR spectroscopy. Scanning Electron Microscopy (SEM and X-ray diffraction (XRD were used to analyze the effects of hydrolysis, delignification, and bleaching on the structure of the fibers. Two different thermal analysis techniques were used to study the bleaching cellulose fibers. These techniques confirmed that cellulose fibers were isolated from sugarcane bagasse. A future goal is to use these fibers as reinforcement elements in composites, organic-inorganic hybrid, and membranes for nanofiltration.

  19. Isatin Derived Spirocyclic Analogues with α-Methylene-γ-butyrolactone as Anticancer Agents: A Structure-Activity Relationship Study.

    Science.gov (United States)

    Rana, Sandeep; Blowers, Elizabeth C; Tebbe, Calvin; Contreras, Jacob I; Radhakrishnan, Prakash; Kizhake, Smitha; Zhou, Tian; Rajule, Rajkumar N; Arnst, Jamie L; Munkarah, Adnan R; Rattan, Ramandeep; Natarajan, Amarnath

    2016-05-26

    Design, synthesis, and evaluation of α-methylene-γ-butyrolactone analogues and their evaluation as anticancer agents is described. SAR identified a spirocyclic analogue 19 that inhibited TNFα-induced NF-κB activity, cancer cell growth and tumor growth in an ovarian cancer model. A second iteration of synthesis and screening identified 29 which inhibited cancer cell growth with low-μM potency. Our data suggest that an isatin-derived spirocyclic α-methylene-γ-butyrolactone is a suitable core for optimization to identify novel anticancer agents.

  20. Tooth-bleaching procedures and their controversial effects: A literature review

    OpenAIRE

    Alqahtani, Mohammed Q.

    2014-01-01

    Aim: This review article will help clinicians improve their understanding of the history of bleaching procedures, bleaching types, components, mechanisms, and their effects on soft tissue, tooth structures, resin composite, and bonding. Methods: The controversial issues about bleaching procedures and their effects are reviewed. Additionally, the consequences of pre- and post-bleaching on the bonding potential of composite resin restorations to tooth structure are discussed. Conclusion: ...

  1. In vitro activities of new and conventional antifungal agents against clinical Scedosporium isolates.

    NARCIS (Netherlands)

    Meletiadis, J.; Meis, J.F.G.M.; Mouton, J.W.; Rodriguez-Tudela, J.L.; Donnelly, J.P.; Verweij, P.E.

    2002-01-01

    The susceptibilities of 13 clinical isolates of Scedosporium apiospermum and 55 clinical isolates of S. prolificans to new and conventional drugs belonging to three different classes of antifungal agents, the azoles (miconazole, itraconazole, voriconazole, UR-9825, posaconazole), the polyenes (ampho

  2. Coral diseases and bleaching on Colombian Caribbean coral reefs.

    Science.gov (United States)

    Navas-Camacho, Raúl; Gil-Agudelo, Diego Luis; Rodríguez-Ramírez, Alberto; Reyes-Nivia, María Catalina; Garzón-Ferreira, Jaime

    2010-05-01

    Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC) has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá). The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10 x 2m) with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters) are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2), and Urabá had high numbers with bleaching (54.4 colonies/m2). Of the seven reported coral diseases studied, Dark Spots Disease (DSD), and White Plague Disease (WPD) were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A. grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years) variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few long

  3. Activation of p53 in Human and Murine Cells by DNA-Damaging Agents Differentially Regulates Aryl Hydrocarbon Receptor Levels.

    Science.gov (United States)

    Panchanathan, Ravichandran; Liu, Hongzhu; Choubey, Divaker

    2015-01-01

    Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates multiple cellular processes. The anticancer drug doxorubicin (DOX) can activate AhR-mediated transcription of target genes. Because DOX in cells activates a DNA damage response involving ataxia telangiectasia-mutated (ATM)-mediated activation of p53, we investigated whether the activation of the p53 in cells by DNA-damaging agents such as DOX or bleomycin could regulate the AhR levels. Here we report that activation of p53 by DNA-damaging agents in human cells increased levels of AhR through a posttranscriptional mechanism. Accordingly, fibroblasts from ATM patients, which are defective in p53 activation, expressed reduced constitutive levels of AhR and treatment of cells with bleomycin did not appreciably increase the AhR levels. Further, activation of p53 in cells stimulated the expression of AhR target genes. In murine cells, activation of p53 reduced the levels of AhR messenger RNA and protein and reduced the expression of AhR target genes. Our observations revealed that activation of p53 in human and murine cells differentially regulates AhR levels.

  4. Recombinant interferon alfa-2a, an active agent in advanced cutaneous T-cell lymphomas.

    Science.gov (United States)

    Bunn, P A; Ihde, D C; Foon, K A

    1987-01-01

    The cutaneous T-cell lymphomas including mycosis fungoides and the Sézary syndrome, are indolent lymphomas with early systemic dissemination. Like the indolent B-cell lymphomas, they cannot be cured by currently available systemic chemotherapy so new systemic therapies need to be developed. A study of very high-dose recombinant interferon alfa-2a was, therefore, initiated in 20 patients with advanced cutaneous T-cell lymphoma (5 in stage II, 2 in stage III and 13 in stage IV). All patients were refractory to at least 2 standard therapies, including topical nitrogen mustard (18 patients), psoralens and ultraviolet A light (12 patients), total skin electron irradiation (14 patients) and systemic chemotherapy (16 patients). Nine out of 20 patients (45%; 95% confidence interval 25-69%) had either objective partial or complete responses within 3 months of starting treatment. Maximal response, however, often did not occur for at least one year. The median duration of response was 5.5 months and all complete responses lasted more than 2 years. Response frequencies were equal at both cutaneous and extracutaneous sites and in patients with or without prior chemotherapy. Toxicity was exhibited primarily as a flu-like syndrome consisting of fever, malaise, fatigue, anorexia and weight loss which necessitated dose reductions in all patients. Transient elevations in liver function and decreases in renal function and granulocyte counts occurred in some patients. It is concluded that interferon alfa-2a is highly active against advanced cutaneous T-cell lymphomas and that it should be studied in its early stages. It should also be evaluated in combination with other biological agents and with chemotherapy.

  5. Methodological optimization of applying neuroactive agents for the study of locomotor-like activity in the mudpuppies (Necturus Maculatus)

    Science.gov (United States)

    Lavrov, Igor; Cheng, Jianguo

    2008-01-01

    We compared the effects of mode of delivery of neuroactive agents and the effects of Dimethyl sulfoxide (DMSO), a vehicle for dissolving neuroactive agents, on locomotor-like activity in vitro. By superfusion, D-glutamate (0.3 – 0.9 mM) produced robust walking-like activity at superfusion rates 10–25 ml/min. In contrast, bolus application of the same or higher doses of glutamate (0.1–1.5 mM) failed to induce any rhythmic activity. Superfusion with AP-5, a NMDA receptor antagonist, produced dose-dependent inhibition of the ongoing walking-like activity induced by D-glutamate and completely blocked the activity at 20 µM. In contrast, bolus application of AP-5 did not block the walking-like activity at concentrations up to 120 µM. Similarly, superfusion of AP-5 inhibited the initiation of walking-like activity and completely blocked the initiation at 20 µM, while bolus application of AP-5 failed to do so at concentrations up to 120 µM. Superfusion of strychnine, a glycine receptor antagonist, blocked the walking-like activity at concentrations of 3–5 µM, while its bolus application altered NMDA-induced, but not glutamate-induced, walking-like activity to a synchronized pattern. DMSO significantly affected the walking-like activity in a dose-dependent manner at concentrations ranging 1–10% (v/v). These results demonstrate that the way by which the neuroactive agents are applied is a significant factor that determines the outcome of experiments on the neural control of locomotion. Also, the dose-dependent effects of DMSO on the activity of neural networks for locomotion should be taken into account in data interpretation. PMID:18692523

  6. 40 CFR 430.20 - Applicability; description of the bleached papergrade kraft and soda subcategory.

    Science.gov (United States)

    2010-07-01

    ... bleached papergrade kraft and soda subcategory. 430.20 Section 430.20 Protection of Environment... POINT SOURCE CATEGORY Bleached Papergrade Kraft and Soda Subcategory § 430.20 Applicability; description of the bleached papergrade kraft and soda subcategory. The provisions of this subpart apply...

  7. Effect of the Purple Corn Beverage "Chicha Morada" in Composite Resin during Dental Bleaching.

    Science.gov (United States)

    Acuña, Eric Dario; Delgado-Cotrina, Leyla; Rumiche, Francisco Aurelio; Tay, Lidia Yileng

    2016-01-01

    During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada), green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n = 5): purple corn (P), purple corn + bleaching (PB), green tea (T), green tea + bleaching (TB), distilled water (W), and distilled water + bleaching (WB). In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p composite resin regardless of the bleaching procedure. However, purple corn was the only beverage that caused a perceptible color change (ΔE > 3.3).

  8. Effect of nightguard vital bleaching gel on the color stability of provisional restorative materials

    Directory of Open Access Journals (Sweden)

    Salwa Omar Bajunaid

    2016-01-01

    Conclusions: Composite-based provisional material showed highest color stability when exposed to vital tooth bleaching gel, whereas methacrylate-based material was the least color stable. Polycarbonate crowns were more color stable when exposed to 15% bleaching gel as opposed to 10% bleaching gel.

  9. KINETICS OF DELIGNIFICATION AND CARBOHYDRATE DEGRADATION DURING OXYGEN BLEACHING

    Institute of Scientific and Technical Information of China (English)

    K. L Nguyen

    2004-01-01

    Carbohydrate degradation during oxygen bleaching is associated with cleavage reactions. It is apparent that the loss of the cellulose DP (degree ofpolymisation)is strongly affected by the extent of the delignification. A strong linear correlation can be established between the DP of cellulose chains and the residual lignin in the pulp. The Nuclear Growth concept and Percolation Theory for heterogenous system can be combined to formulate kinetic models for both the delignification and the degradation of carbohydrate. The models prediction is statistically robust and can be applied to different pulps at different bleaching conditions.

  10. Climatological context for large-scale coral bleaching

    Science.gov (United States)

    Barton, A. D.; Casey, K. S.

    2005-12-01

    Large-scale coral bleaching was first observed in 1979 and has occurred throughout virtually all of the tropics since that time. Severe bleaching may result in the loss of live coral and in a decline of the integrity of the impacted coral reef ecosystem. Despite the extensive scientific research and increased public awareness of coral bleaching, uncertainties remain about the past and future of large-scale coral bleaching. In order to reduce these uncertainties and place large-scale coral bleaching in the longer-term climatological context, specific criteria and methods for using historical sea surface temperature (SST) data to examine coral bleaching-related thermal conditions are proposed by analyzing three, 132 year SST reconstructions: ERSST, HadISST1, and GISST2.3b. These methodologies are applied to case studies at Discovery Bay, Jamaica (77.27°W, 18.45°N), Sombrero Reef, Florida, USA (81.11°W, 24.63°N), Academy Bay, Galápagos, Ecuador (90.31°W, 0.74°S), Pearl and Hermes Reef, Northwest Hawaiian Islands, USA (175.83°W, 27.83°N), Midway Island, Northwest Hawaiian Islands, USA (177.37°W, 28.25°N), Davies Reef, Australia (147.68°E, 18.83°S), and North Male Atoll, Maldives (73.35°E, 4.70°N). The results of this study show that (1) The historical SST data provide a useful long-term record of thermal conditions in reef ecosystems, giving important insight into the thermal history of coral reefs and (2) While coral bleaching and anomalously warm SSTs have occurred over much of the world in recent decades, case studies in the Caribbean, Northwest Hawaiian Islands, and parts of other regions such as the Great Barrier Reef exhibited SST conditions and cumulative thermal stress prior to 1979 that were comparable to those conditions observed during the strong, frequent coral bleaching events since 1979. This climatological context and knowledge of past environmental conditions in reef ecosystems may foster a better understanding of how coral reefs will

  11. Optimization and selection of coagulating agents in the advanced treatment of washing & bleaching effluent from dissolving pulp process%溶解木浆中段废水深度处理中混凝剂的选择及优化

    Institute of Scientific and Technical Information of China (English)

    姜红梅; 毛长凤; 赵克侠

    2013-01-01

      溶解木浆中段废水先经模拟好氧生化系统处理后,采用混凝法进行深度处理试验。结果表明:硫酸铝适用于溶解木浆废水深度治理,并在废水处理效果及处理成本方面优于聚合氯化铝、聚合硫酸铁、氯化铁等无机絮凝剂。硫酸铝投加后pH值在6~7范围内,搭配阴离子PAM去除浊度的效果更明显。生化模拟试验出水作为混凝原水,先经预酸化再好氧生化水质的混凝处理效果优于好氧生化的水质:处理后出水COD<100mg/L,色度<50倍;单耗处理成本更低,处理成本降低0.264~0.44元。%The washing&bleaching effluent of dissolving pulp was first treated with simulated aerobic biochemical process, advanced treatment was done by coagulation process. The results show that aluminum sulfate is suitable for dissolving pulp wastewater advanced treatment, with which the treating effect and the treating cost are better than that of polymeric aluminum chloride, poly ferric sulfate, ferric chloride and other inorganic flocculants. When aluminum sulfate is added with the combination of anionic PAM, pH range of 6~7, turbidity removal effect is more obvious. The waste water treated first by pre-acidification and aerobic biochemical process has a better treating effect in coagulation than the waste water treated only by aerobic biochemical process, reaching COD less than 100mg/L, chroma less than 50 times, with the treatment cost reduced by 0.264~0.44 yuan/t.

  12. Reactive skin decontamination lotion (RSDL) for the decontamination of chemical warfare agent (CWA) dermal exposure.

    Science.gov (United States)

    Schwartz, M D; Hurst, C G; Kirk, M A; Reedy, S J D; Braue, E H

    2012-08-01

    Rapid decontamination of the skin is the single most important action to prevent dermal absorption of chemical contaminants in persons exposed to chemical warfare agents (CWA) and toxic industrial chemicals (TICs) as a result of accidental or intentional release. Chemicals on the skin may be removed by mechanical means through the use of dry sorbents or water. Recent interest in decontamination systems which both partition contaminants away from the skin and actively neutralize the chemical has led to the development of several reactive decontamination solutions. This article will review the recently FDA-approved Reactive Skin Decontamination Lotion (RSDL) and will summarize the toxicity and efficacy studies conducted to date. Evidence of RSDL's superior performance against vesicant and organophosphorus chemical warfare agents compared to water, bleach, and dry sorbents, suggests that RSDL may have a role in mass human exposure chemical decontamination in both the military and civilian arenas.

  13. Analysis of a radioactive lens and of the correlated UV light bleaching properties

    Energy Technology Data Exchange (ETDEWEB)

    Marzocchi, Olaf [European Patent Office, The Hague (Netherlands). Dept. of Applied Physics; Romanello, Vincenco [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Nukleare Entsorgung (INE)

    2015-07-01

    Topic of the present work is the measurement of the activity of a reflex camera objective, known to include radioactive glass lenses, using a Geiger-Mueller counter and HPGe detectors. Using the calculated data, the dose to the eye lens during normal use is also estimated. Since thoriated lenses get a yellow tint with age, the effectiveness of UV light on the bleaching of the lens is is quantified. As last step, the thickest glas element has been cut and used to produce a long self-exposure on film.

  14. Taxonomic, Spatial and Temporal Patterns of Bleaching in Anemones Inhabited by Anemonefishes

    KAUST Repository

    Hobbs, Jean-Paul A.

    2013-08-08

    Background:Rising sea temperatures are causing significant destruction to coral reef ecosystems due to coral mortality from thermally-induced bleaching (loss of symbiotic algae and/or their photosynthetic pigments). Although bleaching has been intensively studied in corals, little is known about the causes and consequences of bleaching in other tropical symbiotic organisms.Methodology/Principal Findings:This study used underwater visual surveys to investigate bleaching in the 10 species of anemones that host anemonefishes. Bleaching was confirmed in seven anemone species (with anecdotal reports of bleaching in the other three species) at 10 of 19 survey locations spanning the Indo-Pacific and Red Sea, indicating that anemone bleaching is taxonomically and geographically widespread. In total, bleaching was observed in 490 of the 13,896 surveyed anemones (3.5%); however, this percentage was much higher (19-100%) during five major bleaching events that were associated with periods of elevated water temperatures and coral bleaching. There was considerable spatial variation in anemone bleaching during most of these events, suggesting that certain sites and deeper waters might act as refuges. Susceptibility to bleaching varied between species, and in some species, bleaching caused reductions in size and abundance.Conclusions/Significance:Anemones are long-lived with low natural mortality, which makes them particularly vulnerable to predicted increases in severity and frequency of bleaching events. Population viability will be severely compromised if anemones and their symbionts cannot acclimate or adapt to rising sea temperatures. Anemone bleaching also has negative effects to other species, particularly those that have an obligate relationship with anemones. These effects include reductions in abundance and reproductive output of anemonefishes. Therefore, the future of these iconic and commercially valuable coral reef fishes is inextricably linked to the ability of host

  15. Taxonomic, spatial and temporal patterns of bleaching in anemones inhabited by anemonefishes.

    Directory of Open Access Journals (Sweden)

    Jean-Paul A Hobbs

    Full Text Available BACKGROUND: Rising sea temperatures are causing significant destruction to coral reef ecosystems due to coral mortality from thermally-induced bleaching (loss of symbiotic algae and/or their photosynthetic pigments. Although bleaching has been intensively studied in corals, little is known about the causes and consequences of bleaching in other tropical symbiotic organisms. METHODOLOGY/PRINCIPAL FINDINGS: This study used underwater visual surveys to investigate bleaching in the 10 species of anemones that host anemonefishes. Bleaching was confirmed in seven anemone species (with anecdotal reports of bleaching in the other three species at 10 of 19 survey locations spanning the Indo-Pacific and Red Sea, indicating that anemone bleaching is taxonomically and geographically widespread. In total, bleaching was observed in 490 of the 13,896 surveyed anemones (3.5%; however, this percentage was much higher (19-100% during five major bleaching events that were associated with periods of elevated water temperatures and coral bleaching. There was considerable spatial variation in anemone bleaching during most of these events, suggesting that certain sites and deeper waters might act as refuges. Susceptibility to bleaching varied between species, and in some species, bleaching caused reductions in size and abundance. CONCLUSIONS/SIGNIFICANCE: Anemones are long-lived with low natural mortality, which makes them particularly vulnerable to predicted increases in severity and frequency of bleaching events. Population viability will be severely compromised if anemones and their symbionts cannot acclimate or adapt to rising sea temperatures. Anemone bleaching also has negative effects to other species, particularly those that have an obligate relationship with anemones. These effects include reductions in abundance and reproductive output of anemonefishes. Therefore, the future of these iconic and commercially valuable coral reef fishes is inextricably linked

  16. Evaluation of RSDL, M291 SDK, 0.5 Bleach, 1% Soapy Water and SERPACWA: Part 11: Challenge with EA4243 (VR, Russian VX)

    Science.gov (United States)

    2016-01-01

    PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Braue, EH, Jr, Doxzon, BF, Lumpkin, HL, Smith, KH, Devorak, JL, Stevenson, RS 5d. PROJECT NUMBER 5e. TASK NUMBER...diluted 1 to 10) and1% soapy water solution (liquid dish detergent) to decontaminate intact skin exposed to chemical warfare agents. Reactive Skin...delayed decontamination, Reactive Skin Decontamination Lotion (RSDL), bleach, soapy water, M291 Skin Decontamination Kit, VR, Skin Exposure Reduction

  17. Efek Gel Ekstrak Kulit Buah Manggis (Garcinia Mangostana pada Perlekatan Komposit pasca In-Office Bleaching

    Directory of Open Access Journals (Sweden)

    Farah Amiria

    2015-06-01

    testing on email. The results show that negative-control and positive-control group scores were 25,82±2,88 Mpa and 37,68±1,06 Mpa, followed by the scores of 10%, 20%, and 40% mangosteen extract gel groups which were 26,54±2,68; 32,64±2,33; and 57,34±1,51 Mpa respectively. Significant higher shear bond strength values were observed in 20% and 40% mangosteen extract gel groups compared to the negative-control and positive-control group (p<0,05. The increasing concentration of mangosteen extract gel provided increasing number of email fractures. Mangosteen extract gel 20% and 40% improve the shear bond strength of composite, confirming its potential as an antioxidant agent for the teeth post in-office bleaching.

  18. Brownian agents and active particles collective dynamics in the natural and social sciences

    CERN Document Server

    Schweitzer, Frank

    2007-01-01

    ""This book lays out a vision for a coherent framework for understanding complex systems"" (from the foreword by J. Doyne Farmer). By developing the genuine idea of Brownian agents, the author combines concepts from informatics, such as multiagent systems, with approaches of statistical many-particle physics. This way, an efficient method for computer simulations of complex systems is developed which is also accessible to analytical investigations and quantitative predictions. The book demonstrates that Brownian agent models can be successfully applied in many different contexts, ranging from

  19. Chlorophyll bleaching by UV-irradiation in vitro and in situ: Absorption and fluorescence studies

    Energy Technology Data Exchange (ETDEWEB)

    Zvezdanovic, Jelena [Faculty of Technology, University of Nish, Bulevar oslobodjenja 124, 16000 Leskovac (Serbia)], E-mail: jelite74@yahoo.com; Cvetic, Tijana [Faculty of Biology, University of Belgrade, Takovska 43, Belgrade 11000 (Serbia); Veljovic-Jovanovic, Sonja [Center for Multidisciplinary Studies, University of Belgrade, Kneza Viseslava la, Belgrade 11030 (Serbia); Markovic, Dejan [Faculty of Technology, University of Nish, Bulevar oslobodjenja 124, 16000 Leskovac (Serbia)], E-mail: dejan_markovic57@yahoo.com

    2009-01-15

    Chlorophyll bleaching by UV-irradiation has been studied by absorbance and fluorescence spectroscopy in extracts containing mixtures of photosynthetic pigments, in acetone and n-hexane solutions, and in aqueous thylakoid suspensions. Chlorophyll undergoes destruction (bleaching) accompanied by fluorescent transient formation obeying first-order kinetics. The bleaching is governed by UV-photon energy input, as well as by different chlorophyll molecular organizations in solvents of different polarities (in vitro), and in thylakoids (in situ). UV-C-induced bleaching of chlorophylls in thylakoids is probably caused by different mechanisms compared to UV-A- and UV-B-induced bleaching.

  20. Chlorine bleaches - A significant long term source of mercury pollution

    Science.gov (United States)

    Siegel, S. M.; Eshleman, A.

    1975-01-01

    Products of industrial electrolysis of brine - NaOCl-based bleaches and NaOH - yielded 17 to 1290 ppb of Hg upon flameless atomic absorption analysis. Compared with current U.S. rejection value of 5 ppb for potable waters, the above levels seem sufficiently high to be a matter of environmental concern.

  1. Bleaching in vital deciduous teeth – a clinical case

    Directory of Open Access Journals (Sweden)

    José Carlos Pettorossi Imparato

    2008-01-01

    Full Text Available There has been growing concern and search for esthetic beauty and harmony over the last few years. This concern does not form part ofadults’ lives only, but also of children’s. Among the substances used for bleaching dental structures, the most outstanding are those whoseactive principle is hydrogen peroxide-based . The present study reports a clinical case of a 4-year-old girl that suffered trauma of tooth 61 with consequent color alteration, but with no alteration in pulp vitality. The main complaint by the patient and her guardians concerned esthetics, therefore external dental bleaching was performed, using Opalescence Xtra® (Ultradent, in two sessions with an interval of one month between them. External in office bleaching was the treatment of choice, due to the tooth vitality, patient’s age and presence of only one darkened tooth. After the bleaching treatments an improvement in the darkening was observed, and both the child and her guardians were satisfied with the esthetic result.

  2. Quantification of cross-bleaching during infrared (IR) light stimulation

    DEFF Research Database (Denmark)

    Kreutzer, Sebastian; Hülle, Daniela; Thomsen, Kristina Jørkov;

    2013-01-01

    The cross-bleaching behaviour of automated Risø TL/OSL (DA-12, DA-15, DA-20) luminescence readers is investigated. By design, up to 24 or 48 aliquots can be stored on a carousel in a single measurement chamber. Due to this construction, irradiation or illumination on one sample may affect...... measurements of feldspar or polymineral samples it is important to keep the time constant between the (midpoint of the) irradiation and the subsequent read out to avoid the malign effects of anomalous fading in laboratory constructed dose response curves. This may be achieved by running all measurements...... on subsequent samples. Here we investigate the size of this reduction due to cross-bleaching from the IR diodes and quantify the cross-bleaching for 10 different Risø TL/OSL readers produced between 1994 and 2011. We find that cross-bleaching from the IR diodes is worse than from the blue diodes. Using the “run...

  3. Influence of Concentration and Activation on Hydrogen Peroxide Diffusion through Dental Tissues In Vitro

    Directory of Open Access Journals (Sweden)

    Carlos R. G. Torres

    2013-01-01

    Full Text Available This study evaluated the effect of physical and chemical activation on the diffusion time of different concentrations of hydrogen peroxide (HP bleaching agents through enamel and dentin. One hundred and twenty bovine cylindrical specimens were divided into six groups (n=20: 20% HP ; 20% HP with light activation; 20% HP with manganese gluconate; 35% HP; 35% HP with light activation; and 35% HP with manganese gluconate. The specimens were fixed over transparent epoxy wells with internal cavities to simulate a pulpal chamber. This chamber was filled with an enzymatic reagent to simulate pulpal fluid. The bleaching gels were applied on enamel surface and the image of the pulpal fluid was captured by a video camera to monitor the time of peroxide penetration in each specimen. ANOVA analysis showed that concentration and type of activation of bleaching gel significantly influenced the diffusion time of HP (P<0.05. 35% HP showed the lowest diffusion times compared to the groups with 20% HP gel. The light activation of HP decreased significantly the diffusion time compared to chemical activation. The highest diffusion time was obtained with 20% HP chemically activated. The diffusion time of HP was dependent on activation and concentration of HP. The higher concentration of HP diffused through dental tissues more quickly.

  4. Photocatalytic thin films coupled with polymeric microcapsules for the controlled-release of volatile agents upon solar activation

    Science.gov (United States)

    Oliveira, L. F.; Marques, J.; Coutinho, P. J. G.; Parpot, P.; Tavares, C. J.

    2013-06-01

    This work reportson the application of solar-activated photocatalytic thin films that allow the controlled-release of volatile agents (e.g., insecticides, repellents) from the interior of adsorbedpolymericmicrocapsules. In order to standardize the tests, a quantification of the inherent controlled-release of a particular volatile agent is determined by gas chromatography coupled to mass spectroscopy, so that an application can be offered to a wide range of supports from various industrial sectors, such as in textiles (clothing, curtains, mosquito nets). This technology takes advantage of the established photocatalytic property of titanium dioxide (TiO2) for the use as an active surface/site to promote the controlled-release of a specific vapor (volatile agentfrom within the aforementioned microcapsules.

  5. Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

    Science.gov (United States)

    Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

    2012-01-01

    The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (pperoxide passage than did GD and GE (pperoxide placed into the pulp chamber passed through the dental hard tissues, reaching the external surface and the periodontal tissue. The cementum surface

  6. Quantifying activation of perfluorocarbon-based phase-change contrast agents using simultaneous acoustic and optical observation.

    Science.gov (United States)

    Li, Sinan; Lin, Shengtao; Cheng, Yi; Matsunaga, Terry O; Eckersley, Robert J; Tang, Meng-Xing

    2015-05-01

    Phase-change contrast agents in the form of nanoscale droplets can be activated into microbubbles by ultrasound, extending the contrast beyond the vasculature. This article describes simultaneous optical and acoustical measurements for quantifying the ultrasound activation of phase-change contrast agents over a range of concentrations. In experiments, decafluorobutane-based nanodroplets of different dilutions were sonicated with a high-pressure activation pulse and two low-pressure interrogation pulses immediately before and after the activation pulse. The differences between the pre- and post-interrogation signals were calculated to quantify the acoustic power scattered by the microbubbles activated over a range of droplet concentrations. Optical observation occurred simultaneously with the acoustic measurement, and the pre- and post-microscopy images were processed to generate an independent quantitative indicator of the activated microbubble concentration. Both optical and acoustic measurements revealed linear relationships to the droplet concentration at a low concentration range <10(8)/mL when measured at body temperature. Further increases in droplet concentration resulted in saturation of the acoustic interrogation signal. Compared with body temperature, room temperature was found to produce much fewer and larger bubbles after ultrasound droplet activation.

  7. OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT

    Directory of Open Access Journals (Sweden)

    Fernando de Carvalho

    2010-08-01

    Full Text Available The effect of medium consistency ozone stage pH was evaluated for brown and oxygen delignified eucalyptus kraft pulp samples obtained from VCP - Luiz Antônio pulp mill. These samples were used as such or previously treated with the hot acid stage (A. The main objective of this study was to determine the viability of increasing the ozone stage pH aiming at decreasing bleaching variable costs. The ozone stage was studied in the pH range of 2.5-9.0, taking into account some important variables which affect ozone bleaching: (1 pulp kappa number entering the ozone stage, (2 reactivity of ozone towards lignin versus hexenuronic acids (HexA´s, (3 pulp treatments prior to ozone stage (acid hydrolysis, and (4 pulp treatments after the ozone stage (extraction or a chlorine dioxide stage.  Therefore, the impact of ozone stage pH was investigated in bleaching process such as Z/DEop vs AZ/DEop, Z/DEopD vs AZ/DEopD, Z/E vs AZ/E. The results were interpreted based on ozone stage efficiency and selectivity, and overall bleaching performance measured by the total bleaching chemical consumption required to achieve full brightness, pulp quality and environmental impact. It was concluded that the increase of ozone stage pH from 2.5 to 7.0 has a slightly negative impact on the efficiency and selectivity, measured after Z/DEop sequence, but this effect is not expressive in the end of Z/DEopD bleaching sequence. The increase of ozone stage pH from 2.5 to 7.0 in the sequence Z/DEopD is cost-effective at industrial level because it represents expressive reduction of sulphuric acid and caustic soda demand for pH control in the bleaching plant. These gain areas achieved without any significant changes in pulp quality and effluent load discharge. Nevertheless, the increase of ozone stage pH from 2.5 to 7.0 has a very high negative impact on the efficiency and selectivity for the Z/E and AZ/E processes and it is not recommended in such cases.

  8. Can a bleaching toothpaste containing Blue Covarine demonstrate the same bleaching as conventional techniques? An in vitro, randomized and blinded study

    Directory of Open Access Journals (Sweden)

    Andréa Abi Rached DANTAS

    2015-12-01

    Full Text Available ABSTRACT Objective The purpose of this in vitro study was to compare the efficacy of a bleaching toothpaste containing Blue Covarine vs. conventional tooth bleaching techniques using peroxides (both in-office and at-home. Material and Methods Samples were randomly distributed into five experimental groups (n=15: C - Control; BC – Bleaching toothpaste containing Blue Covarine; WBC – Bleaching toothpaste without Blue Covarine; HP35 - In-office bleaching using 35% hydrogen peroxide; and CP10 – At-home bleaching with 10% carbamide peroxide. The dental bleaching efficacy was determined by the color difference (ΔE, luminosity (ΔL, green-red axis (Δa, and blue-yellow axis (Δb. The CIELab coordinates were recorded with reflectance spectroscopy at different times: T0 - baseline, T1 – immediately after bleaching, T2 - 7 days, T3 - 14 days, and T4 - 21 days after the end of treatments. Data were analyzed by a repeated measures mixed ANOVA and post hoc Bonferroni test, with a significance level of 5%. Results No significant differences were found between the treatment groups C, BC, and WBC. The groups HP35 and CP10 showed significantly higher whitening efficacy than groups C, BC, and WBC. Conclusions There were no significant differences in the whitening efficacy between a Blue Covarine containing toothpaste, a standard whitening toothpaste, and a control. Neither of the whitening toothpastes tested were as effective as in-office or at-home bleaching treatments.

  9. In-office bleaching effects on the pulp flow and tooth sensitivity - case series.

    Science.gov (United States)

    Cartagena, Andrés Felipe; Parreiras, Sibelli Olivieri; Loguercio, Alessandro Dourado; Reis, Alessandra; Campanha, Nara Hellen

    2015-01-01

    Laser Doppler flowmetry (LDF) is a noninvasive method capable of evaluating variations in pulp blood flow (PBF) and pulp vitality. This method has thus far not been used to assess changes in blood flow after in-office bleaching. The aim of this case series report was to measure changes in PBF by LDF in the upper central incisor of three patients submitted to in-office bleaching. The buccal surfaces of the upper arch were bleached with a single session of 35% hydrogen peroxide gel with three 15-min applications. The color was recorded using a value-oriented Vita shade guide before in-office bleaching and one week after the procedure. The tooth sensitivity (TS) in a verbal scale was reported, and PBF was assessed by LDF before, immediately, and one week after the bleaching session. The lower arch was submitted to dental bleaching but not used for data assessment. A whitening degree of 3 to 4 shade guide units was detected. All participants experienced moderate to considerable TS after the procedure. The PBF readings reduced 20% to 40% immediately after bleaching. One week post-bleaching, TS and PBF were shown to be equal to baseline values. A reversible decrease of PBF was detected immediately after bleaching, which recovered to the baseline values or showed a slight increase sooner than one week post-bleaching. The LDF method allows detection of pulp blood changes in teeth submitted to in-office bleaching, but further studies are still required.

  10. Effect of the Purple Corn Beverage “Chicha Morada” in Composite Resin during Dental Bleaching

    Directory of Open Access Journals (Sweden)

    Eric Dario Acuña

    2016-01-01

    Full Text Available During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada, green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n=5: purple corn (P, purple corn + bleaching (PB, green tea (T, green tea + bleaching (TB, distilled water (W, and distilled water + bleaching (WB. In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p3.3.

  11. In-office bleaching effects on the pulp flow and tooth sensitivity – case series

    Directory of Open Access Journals (Sweden)

    Andrés Felipe CARTAGENA

    2015-01-01

    Full Text Available Laser Doppler flowmetry (LDF is a noninvasive method capable of evaluating variations in pulp blood flow (PBF and pulp vitality. This method has thus far not been used to assess changes in blood flow after in-office bleaching. The aim of this case series report was to measure changes in PBF by LDF in the upper central incisor of three patients submitted to in-office bleaching. The buccal surfaces of the upper arch were bleached with a single session of 35% hydrogen peroxide gel with three 15-min applications. The color was recorded using a value-oriented Vita shade guide before in-office bleaching and one week after the procedure. The tooth sensitivity (TS in a verbal scale was reported, and PBF was assessed by LDF before, immediately, and one week after the bleaching session. The lower arch was submitted to dental bleaching but not used for data assessment. A whitening degree of 3 to 4 shade guide units was detected. All participants experienced moderate to considerable TS after the procedure. The PBF readings reduced 20% to 40% immediately after bleaching. One week post-bleaching, TS and PBF were shown to be equal to baseline values. A reversible decrease of PBF was detected immediately after bleaching, which recovered to the baseline values or showed a slight increase sooner than one week post-bleaching. The LDF method allows detection of pulp blood changes in teeth submitted to in-office bleaching, but further studies are still required.

  12. Disease incidence is related to bleaching extent in reef-building corals.

    Science.gov (United States)

    Brandt, Marilyn E; McManus, John W

    2009-10-01

    Recent outbreaks of coral bleaching and disease have contributed to substantial declines in the abundance of reef-building coral. Significant attention has been paid to both phenomena in order to determine their effect on reef trajectories. Although each is positively correlated with high temperatures, few studies have explored the potential links between bleaching and disease. A longitudinal study of corals in the Florida Keys was therefore conducted during the 2005 Caribbean bleaching event to quantify bleaching extent and disease incidence in corals, and to determine whether they were related or if they acted as discrete phenomena. These data indicated that overall, a positive correlation exists between bleaching extent and disease incidence. However, the specific interactions between these two phenomena varied among disease bleaching combinations. Montastraea faveolata colonies with greater bleaching intensities later developed white plague (WP) infections. Meanwhile, Siderastrea siderea colonies with dark spot disease (DS) bleached more extensively than apparently healthy colonies. Finally, bleaching and black band disease (BB) co-occurred on Colpophyllia natans throughout the bleaching event. WP, BB, and bleaching are each independently capable of changing the structure of coral populations through loss of living tissue, and DS is an important indicator of reef health. Understanding the dynamics of how these mortality sources interact is critical to understanding mortality patterns and predicting how reef communities will respond to future events.

  13. Single agent lenalidomide activity in multiple myeloma relapse evidenced uniquely by CT/PET

    Directory of Open Access Journals (Sweden)

    Alessandro Gozzetti

    2012-01-01

    Full Text Available A71 year old female with multiple myeloma presented with back pain seven year after autologous stem cell transplant. Skeletal bone survey and magnetic resonance imaging did not show a relapse that was evidenced by CT/PET. Lenalidomide as single agent induced a complete disappearance of the lesions 6 months later at CT/PET

  14. Comparative in vitro activities of selected antimicrobial agents against Aeromonas species and Plesiomonas shigelloides.

    OpenAIRE

    1985-01-01

    The in vitro antimicrobial susceptibilities of fecal isolates of Aeromonas caviae, Aeromonas hydrophila, Aeromonas sobria, and Plesiomonas shigelloides were tested by agar dilution. This in vitro study suggested that ciprofloxacin, enoxacin, norfloxacin, tetracycline, and trimethoprim-sulfamethoxazole might be effective oral agents for treatment of diarrhea involving Aeromonas spp. or P. shigelloides.

  15. Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme

    Science.gov (United States)

    2011-03-18

    carboxylesterase 1 in covalent complexes with the chemical warfare agents soman and tabun . Biochemistry 46: 5063–5071. 8. Hemmert AC, Otto TC, Wierdl M, Edwards CC...sarin, tabun , and cyclohexyl methylphosphonate-modified human butyrylcholinesterase. Chem Res Toxicol 22: 1680–1688. 14. Lenz DE, Broomfield CA, Yeung

  16. Comparison of the In Vitro Activities of Newer Triazoles and Established Antifungal Agents against Trichophyton rubrum

    NARCIS (Netherlands)

    Deng, S.; Zhang, C.; Seyedmousavi, S.; Zhu, S.; Tan, X.; Wen, Y.; Huang, X.; Lei, W.; Zhou, Z.; Fang, W.; Shen, S.; Deng, D.; Pan, W.; Liao, W.

    2015-01-01

    One hundred eleven clinical Trichophyton rubrum isolates were tested against 7 antifungal agents. The geometric mean MICs of all isolates were, in increasing order: terbinafine, 0.03 mg/liter; voriconazole, 0.05 mg/liter; posaconazole, 0.11 mg/liter; isavuconazole, 0.13 mg/liter; itraconazole, 0.26

  17. Characterization of Antifungal Activity and Nail Penetration of ME1111, a New Antifungal Agent for Topical Treatment of Onychomycosis

    OpenAIRE

    Tabata, Yuji; Takei-Masuda, Naomi; Kubota, Natsuki; Takahata, Sho; Ohyama, Makoto; Kaneda, Kaori; Iida, Maiko; Maebashi, Kazunori

    2016-01-01

    Fungal nail infection (onychomycosis) is a prevalent disease in many areas of the world, with a high incidence approaching 23%. Available antifungals to treat the disease suffer from a number of disadvantages, necessitating the discovery of new efficacious and safe antifungals. Here, we evaluate the in vitro antifungal activity and nail penetration ability of ME1111, a novel antifungal agent, along with comparator drugs, including ciclopirox, amorolfine, terbinafine, and itraconazole. ME1111 ...

  18. INFLUENCE OF SURFACE-ACTIVE AGENT CONCENTRATION ON THE SPECTROPHOTOMETRIC BIOMASS ESTIMATION DURING SUBMERGED GROWTH OF Mycobacterium bovis

    Directory of Open Access Journals (Sweden)

    Sakai M.C.

    1997-01-01

    Full Text Available The influence of the surface-active agent Tween 80 (polyoxyethylene 20 sorbitan monoleate on the dispersed growth of Mycobacterium bovis - BCG - was studied. The slopes of the bacterial dry mass / absorbance curves, were significantly reduced, by the increase of the Tween 80 concentration in the medium. Such an influence was probably due to the effect Tween 80 had on the average size of bacterial clumps during the culture carried out in a bench fermenter

  19. High spatial variability in coral bleaching around Moorea (French Polynesia): patterns across locations and water depths.

    Science.gov (United States)

    Penin, Lucie; Adjeroud, Mehdi; Schrimm, Muriel; Lenihan, Hunter Stanton

    2007-02-01

    Mass coral bleaching events are one of the main threats to coral reefs. A severe bleaching event impacted Moorea, French Polynesia, between March and July 2002, causing 55+/-14% of colonies to suffer bleaching around the island. However, bleaching varied significantly across coral genera, locations, and as a function of water depth, with a bleaching level as high as 72% at some stations. Corals in deeper water bleached at a higher rate than those in shallow water, and the north coast was more impacted than the west coast. The relatively small scale of variability in bleaching responses probably resulted from the interaction between extrinsic factors, including hydrodynamic condition, and intrinsic factors, such as differential adaptation of the coral/algal association.

  20. Susceptibility to Coffee Staining during Enamel Remineralization Following the In-Office Bleaching Technique

    DEFF Research Database (Denmark)

    Mori, Aline Akemi; Lima, Fernanda Ferruzzi; Benetti, Ana Raquel

    2016-01-01

    PURPOSE: To assess in situ the enamel mineralization level and susceptibility to coffee staining after in-office bleaching. MATERIALS AND METHODS: Thirty-six human dental fragments assembled into intraoral devices were bleached with 35% hydrogen peroxide and treated as follows: (group 1) no contact...... with coffee; (group 2) immersion in a coffee solution for 30 minutes daily for 7 days, starting 1 week after bleaching; and (group 3) immersion in a coffee solution for 30 minutes daily for 14 days, starting immediately after bleaching. Enamel mineralization and color were assessed before bleaching (T1......), immediately after bleaching (T2), and after 7 (T3) and 14 days (T4). The CIE whiteness index (W*) and closeness to white (ΔW*) following bleaching and/or immersion in coffee were calculated. Data were analyzed with Friedman and Wilcoxon tests or Kruskal-Wallis and Mann-Whitney U-tests (α = 0.05). RESULTS...

  1. Monomer release from nanofilled and microhybrid dental composites after bleaching.

    Directory of Open Access Journals (Sweden)

    Masumeh Hasani Tabatabaee

    2014-02-01

    Full Text Available The aim of this study was to assess the effect of bleaching on elution of monomers from nanofilled and microhybrid composites.80 samples (5mm diameter and 3mm thickness of each composite were prepared. After curing, half of them were randomly polished. Each group was divided into 8 subgroups and immersed in water or 10%, 20% and 30% H2O2 for 3 or 8 hours. Eluted Bis-GMA (Bis-phenol A Glycidyl Dimethacrylate, TEGDMA (Triethyleneglycol Dimethacrylate, UDMA (Urethane Dimethacrylate and BisEMA (Bis-phenol A ethoxylate Dimethacrylate were quantified by high performance liquid chromatography and the results were analyzed by univariate ANOVA and t-test (P<0.05.Bleach significantly increased the overall release of monomers (P<0.001; TEGDMA was released more than Bis-GMA (P<0.001. Supreme released more TEGDMA compared to Z250 (P<0.001. Bleaching increased the release of this monomer (P<0.001. Increasing both the concentration of H2O2, and the immersion time, increased the release of TEGDMA (P<0.001. Polishing had no effect on release of this monomer (P=0.952. Supreme released more Bis-GMA than Z250 (P=0.000. The more concentrated H2O2 caused more elution of Bis-GMA (P= 0.003; while the effect of immersion time was not significant (P=0.824. Polishing increased the release of Bis-GMA (P=0.001. Neither the type of composite nor Bleaching had any effect on release of UDMA (P=0.972 and (P=0.811 respectively. Immersion duration increased the release of UDMA (P=0.002, as well as polishing (P=0.024.Bleaching increased the release of monomers. Nanofilled composites released more monomer than the microfilled.

  2. Light illuminated α-Fe2O3/Pt nanoparticles as water activation agent for photoelectrochemical water splitting.

    Science.gov (United States)

    Li, Xiaodong; Wang, Zhi; Zhang, Zemin; Chen, Lulu; Cheng, Jianli; Ni, Wei; Wang, Bin; Xie, Erqing

    2015-03-16

    The photoelectrochemical (PEC) water splitting is hampered by strong bonds of H2O molecules and low ionic conductivity of pure water. The photocatalysts dispersed in pure water can serve as a water activation agent, which provides an alternative pathway to overcome such limitations. Here we report that the light illuminated α-Fe2O3/Pt nanoparticles may produce a reservoir of reactive intermediates including H2O2, ·OH, OH(-) and H(+) capable of promoting the pure water reduction/oxidation half-reactions at cathode and highly photocatalytic-active TiO2/In2S3/AgInS2 photoanode, respectively. Remarkable photocurrent enhancement has been obtained with α-Fe2O3/Pt as water activation agent. The use of α-Fe2O3/Pt to promote the reactivity of pure water represents a new paradigm for reproducible hydrogen fuel provision by PEC water splitting, allowing efficient splitting of pure water without adding of corrosive chemicals or sacrificial agent.

  3. Augmenting the Antifungal Activity of an Oxidizing Agent with Kojic Acid: Control of Penicillium Strains Infecting Crops

    Directory of Open Access Journals (Sweden)

    Jong H. Kim

    2014-11-01

    Full Text Available Oxidative treatment is one of the strategies for preventing Penicillium contamination in crops/foods. The antifungal efficacy of hydrogen peroxide (H2O2; oxidant was investigated in Penicillium strains by using kojic acid (KA as a chemosensitizing agent, which can enhance the susceptibility of pathogens to antifungal agents. Co-application of KA with H2O2 (chemosensitization resulted in the enhancement of antifungal activity of either compound, when compared to the independent application of each agent alone. Of note, heat enhanced the activity of H2O2 to a greater extent during chemosensitization, whereby the minimum inhibitory or minimum fungicidal concentrations of H2O2 was decreased up to 4 or 13 fold, respectively, at 35–45 °C (heat, when compared to that at 28 °C (normal growth temperature. However, heat didn’t increase the antifungal activity of KA, indicating specificity exists between heat and types of antifungals applied. The effect of chemosensitization was also strain-specific, where P. expansum (both parental and fludioxonil-resistant mutants or P. italicum 983 exhibited relatively higher susceptibility to the chemosensitization, comparing to other Penicillium strains tested. Collectively, chemosensitization can serve as a potent antifungal strategy to lower effective dosages of toxic antifungal substances, such as H2O2. This can lead to coincidental lowering of environmental and health risks.

  4. Effect of Complex Agents on Structure and Activity of Fe-Substituted Rare Earth Hexaaluminate Catalysts for Methane Combustion

    Institute of Scientific and Technical Information of China (English)

    Wu Peng; Hu Ruisheng; Long Zerong; Meng He

    2004-01-01

    A series of catalysts were prepared by using complex sol-gel methods.Experimental results confirm the effect of different agents on structure and activity of Fe-substituted rare earth hexaaluminate catalyst (LaFeAl11 O19 ) for methane combustion.The catalyst is yielded by complex sol-gel, respectively using three different complex agents (maltose, glucose and citric acid).XRD demonstrated that haxaaluminate is the major phase of catalyst prepared by maltose,while LaAlO3 is the major one of the catalyst by glucose and citric acid.At the same time, there is a little LaFeO3 and surface areas as well as 29.5 nm particle diameter when the complex agent is maltose.However, T10 ( temperature for 10% conversion of methane) and T100 ( temperature for 100% conversion of methane) for catalyst by glucose is 543 and 758 ℃, which is the best among the three complex agents for methane combustion.

  5. The cumulative impact of annual coral bleaching can turn some coral species winners into losers.

    Science.gov (United States)

    Grottoli, Andréa G; Warner, Mark E; Levas, Stephen J; Aschaffenburg, Matthew D; Schoepf, Verena; McGinley, Michael; Baumann, Justin; Matsui, Yohei

    2014-12-01

    Mass coral bleaching events caused by elevated seawater temperatures result in extensive coral loss throughout the tropics, and are projected to increase in frequency and severity. If bleaching becomes an annual event later in this century, more than 90% of coral reefs worldwide may be at risk of long-term degradation. While corals can recover from single isolated bleaching and can acclimate to recurring bleaching events that are separated by multiple years, it is currently unknown if and how they will survive and possibly acclimatize to annual coral bleaching. Here, we demonstrate for the first time that annual coral bleaching can dramatically alter thermal tolerance in Caribbean corals. We found that high coral energy reserves and changes in the dominant algal endosymbiont type (Symbiodinium spp.) facilitated rapid acclimation in Porites divaricata, whereas low energy reserves and a lack of algal phenotypic plasticity significantly increased susceptibility in Porites astreoides to bleaching the following year. Phenotypic plasticity in the dominant endosymbiont type of Orbicella faveolata did not prevent repeat bleaching, but may have facilitated rapid recovery. Thus, coral holobiont response to an isolated single bleaching event is not an accurate predictor of its response to bleaching the following year. Rather, the cumulative impact of annual coral bleaching can turn some coral species 'winners' into 'losers', and can also facilitate acclimation and turn some coral species 'losers' into 'winners'. Overall, these findings indicate that cumulative impact of annual coral bleaching could result in some species becoming increasingly susceptible to bleaching and face a long-term decline, while phenotypically plastic coral species will acclimatize and persist. Thus, annual coral bleaching and recovery could contribute to the selective loss of coral diversity as well as the overall decline of coral reefs in the Caribbean.

  6. The Antimicrobial Activity of Wool Fabrics Treated with Crosslinking Agents and Polyhexamethylene Biguanide

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xue; HE JINxin; ZHAN Yizhen

    2009-01-01

    @@ In this study, we used citric acid (CA) as a crosslinking agent, mixed with polyhexamethylene biguanide, to perform a pad-dry-cure treatment on wool fabrics to study its antimicrobial effects and physical properties. The surface characteristic and the structure of wool fabric were investigated by means of scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) was employed to study the crosslinking mechanism of the treated fabric.

  7. Potentiating activity of luteolin on membrane permeabilizing agent and ATPase inhibitor against methicillin-resistant Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Dae-Ki Joung; Dong-Won Shin; Dong-Yeul Kwon; Young-Seob Lee; Sin-Hee Han; Sang-Won Lee; Seon-Woo Cha; Su-Hyun Mun; Ryong Kong; Ok-Hwa Kang; Ho-Jun Song

    2016-01-01

    Objective: To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA). Methods: The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology. Results: Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 μg/mL Tris and 250 μg/mL DCCD were reduced to 60%and 46%, respectively. PGN (15.6 μg/mL) gradually impeded the activity of LUT, and PGN (62.5 μg/mL) completely blocked the activity of LUT on S. aureus. Conclusions: Increased susceptibility to LUT with the Tris and DCCD combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance.

  8. In vitro evaluation of the antibacterial activity of Arctium lappa as a phytotherapeutic agent used in intracanal dressings.

    Science.gov (United States)

    Gentil, Marcelo; Pereira, Juliana Vianna; Sousa, Yara T Corrêa Silva; Pietro, Rosimeire; Neto, Manoel D Sousa; Vansan, Luiz Pascoal; de Castro França, Suzelei

    2006-03-01

    The discovery of natural biocomponents from plants with antibacterial activity on endodontic microbiota may lead to new therapies. This study evaluated the antibacterial activity of a phytotherapeutic agent prepared from an ethyl acetate fraction (AcOEt) extracted from Arctium lappa. This agent was compared with calcium hydroxide as an intracanal dressing. Twenty-seven maxillary canines were instrumented, sterilized and inoculated with a mixed bacterial suspension of Pseudomonas aeruginosa, Escherichia coli, Lactobacillus acidophilus, Streptococcus mutans and Candida albicans. The teeth were divided into three groups and their canals filled with: group 1, calcium hydroxide and propylene glycol; group 2, a paste containing AcOEt fraction of A. lappa and propylene glycol; group 3, propylene glycol (control). At 7, 14 and 30 days, three teeth from each group were opened and a paper point was placed in the root canal for 5 min. The paper points were transferred to Petri dishes with Brain Heart Infusion (BHI). The bacterial growth was classified. Mild bacterial growth was found in group 1 at all time intervals; in group 2 there was severe growth at 7 days, but no growth at 14 and 30 days. The phytotherapeutic agent extracted from an AcOEt fraction of A. lappa inhibited the growth of all the microorganisms in this study.

  9. RGTA OTR4120, a heparan sulfate mimetic, is a possible long-term active agent to heal burned skin.

    Science.gov (United States)

    Garcia-Filipe, S; Barbier-Chassefiere, V; Alexakis, C; Huet, E; Ledoux, D; Kerros, M E; Petit, E; Barritault, D; Caruelle, J P; Kern, P

    2007-01-01

    Burn-related skin fibrosis leads to loss of tissue function and hypertrophic scar formation with damaging consequences for the patient. There is therefore a great need for an efficient agent to treat burned skin. We report that ReGeneraTing Agent (RGTA) reduces burn-induced skin alteration. The tissue-regenerating effect of RGTA OTR4120 was evaluated after 1-6 days and after 10 months in a rat skin burn model. This effect was also examined in vitro using fibroblasts isolated from control and 6-day-old burned skins. We measured production of dermal collagen I, III, and V and activities of metalloproteinases 2 and 9 (MMP-2 and MMP-9). Ratio of collagen III over collagen I production increased 6 days after the burn, because of a decrease in collagen I production. After 10 months, ratio of collagen III over collagen I in burn sites was still increased compared with control skin, because of an increase in collagen III production. Both abnormalities were corrected by OTR4120. OTR4120 increased pro- and active MMP-2 and MMP-9, compared with healthy and burned controls and therefore accelerated remodeling. Similar data were obtained with cultured fibroblasts from healthy and burned skins. OTR4120 enhanced healing in short- and long-term after burns, reducing the formation of fibrotic tissue, and then represents a potential agent to improve burned skin healing.

  10. Enhanced Stability of Blood Matrices Using a Dried Sample Spot Assay to Measure Human Butyrylcholinesterase Activity and Nerve Agent Adducts

    Science.gov (United States)

    Perez, Jonas W.; Pantazides, Brooke G.; Watson, Caroline M.; Thomas, Jerry D.; Blake, Thomas A.; Johnson, Rudolph C.

    2015-01-01

    Dried matrix spots are safer to handle and easier to store than wet blood products, but factors such as intra-spot variability and unknown sample volumes have limited their appeal as a sampling format for quantitative analyses. In this work, we introduce a dried spot activity assay for quantifying butyrylcholinesterase (BChE) specific activity which is BChE activity normalized to the total protein content in a sample spot. The method was demonstrated with blood, serum, and plasma spotted on specimen collection devices (cards) which were extracted to measure total protein and BChE activity using a modified Ellman assay. Activity recovered from dried spots was ∼80% of the initial spotted activity for blood and >90% for plasma and serum. Measuring total protein in the sample and calculating specific activity substantially improved quantification and reduced intra-spot variability. Analyte stability of nerve agent adducts was also evaluated, and the results obtained via BChE-specific activity measurements were confirmed by quantification of BChE adducts using a previously established LC-MS/MS method. The spotted samples were up to 10-times more resistant to degradation compared to unspotted control samples when measuring BChE inhibition by the nerve agents sarin and VX. Using this method, both BChE activity and adducts can be accurately measured from a dried sample spot. This use of a dried sample spot with normalization to total protein is robust, demonstrates decreased intra-spot variability without the need to control for initial sample volume, and enhances analyte stability. PMID:25955132

  11. Antimicrobial activities of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Mourad, K.; Fadhila, K.; Chahinez, M.; Merien, R.; Philippe, L. de; Abdelkader, B.

    2009-07-01

    In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to proteases and detergents. These characteristics suggest the bacteriocin nature of the antimicrobial substance produced by Rhizobium sp. ORN24, named rhizobiocin 24. In contrast, the antimicrobial activity produced by Rhizobium sp. ORN83 was not precipitable with ammonium sulfate; it was smaller than 1,000 KDa molecular weight, heat labile, and protease and detergent resistant. These characteristics could indicate the relationship between the antimicrobial substance produced by Rhizobium sp. ORN 83 and the small bacteriocins described in other rhizobia. (Author) 51 refs.

  12. Semisynthesis and quantitative structure-activity relationship (QSAR) study of some cholesterol-based hydrazone derivatives as insecticidal agents.

    Science.gov (United States)

    Yang, Chun; Shao, Yonghua; Zhi, Xiaoyan; Huan, Qu; Yu, Xiang; Yao, Xiaojun; Xu, Hui

    2013-09-01

    In continuation of our program aimed at the discovery and development of natural-product-based insecticidal agents, four series of novel cholesterol-based hydrazone derivatives were synthesized, and their insecticidal activity was tested against the pre-third-instar larvae of oriental armyworm, Mythimna separata (Walker) in vivo at 1mg/mL. All the derivatives showed the better insecticidal activity than their precursor cholesterol. Quantitative structure-activity relationship (QSAR) model demonstrated that six descriptors such as RDF085v, Mor06u, Mor11u, Dv, HATS0v and H-046, are likely to influence the insecticidal activity of these compounds. Among them, two important ones are the Mor06u and RDF085v.

  13. Study of melanin bleaching after immunohistochemistry of melanin-containing tissues.

    Science.gov (United States)

    Shen, Hongwu; Wu, Wenqiao

    2015-04-01

    Melanin may interfere with immunohistochemical staining. The goal of this study was to investigate the effects of trichloroisocyanuric acid (TCCA) bleaching, potassium permanganate bleaching, and potassium dichromate bleaching on melanin, tissue antigen, and 3,3'-diaminobenzidine (DAB) using melanin-containing and melanin-free tissue samples. Our results demonstrated that all 3 bleaching methods efficiently bleached melanin and partially destroyed tissue antigen. In addition, potassium permanganate bleaching and potassium dichromate bleaching clearly destroyed DAB, whereas TCCA bleaching had no significant effect on DAB. Therefore, neither potassium permanganate nor potassium dichromate is an ideal solution, whereas TCCA might be an ideal solution for melanin bleaching after the immunohistochemical staining of melanin-containing tissues. After immunostaining followed by TCCA bleaching, the melanin could be completely removed in all 120 malignant melanoma tissue sections. Compared with the control, the DAB intensity was clear, and the tissue structure and cellular nuclei were well maintained. It is worth noting that TCCA should be freshly prepared before each experiment, and used within 2 hours of its preparation. In addition, sections should not be incubated with TCCA for over 30 minutes.

  14. Bacteria are not the primary cause of bleaching in the Mediterranean coral Oculina patagonica.

    Science.gov (United States)

    Ainsworth, T D; Fine, M; Roff, G; Hoegh-Guldberg, O

    2008-01-01

    Coral bleaching occurs when the endosymbiosis between corals and their symbionts disintegrates during stress. Mass coral bleaching events have increased over the past 20 years and are directly correlated with periods of warm sea temperatures. However, some hypotheses have suggested that reef-building corals bleach due to infection by bacterial pathogens. The 'Bacterial Bleaching' hypothesis is based on laboratory studies of the Mediterranean invading coral, Oculina patagonica, and has further generated conclusions such as the coral probiotic hypothesis and coral hologenome theory of evolution. We aimed to investigate the natural microbial ecology of O. patagonica during the annual bleaching using fluorescence in situ hybridization to map bacterial populations within the coral tissue layers, and found that the coral bleaches on the temperate rocky reefs of the Israeli coastline without the presence of Vibrio shiloi or bacterial penetration of its tissue layers. Bacterial communities were found associated with the endolithic layer of bleached coral regions, and a community dominance shift from an apparent cyanobacterial-dominated endolithic layer to an algal-dominated layer was found in bleached coral samples. While bacterial communities certainly play important roles in coral stasis and health, we suggest environmental stressors, such as those documented with reef-building corals, are the primary triggers leading to bleaching of O. patagonica and suggest that bacterial involvement in patterns of bleaching is that of opportunistic colonization.

  15. Response of coral assemblages to thermal stress: are bleaching intensity and spatial patterns consistent between events?

    Science.gov (United States)

    Penin, Lucie; Vidal-Dupiol, Jeremie; Adjeroud, Mehdi

    2013-06-01

    Mass bleaching events resulting in coral mortality are among the greatest threats to coral reefs, and are projected to increase in frequency and intensity with global warming. Achieving a better understanding of the consistency of the response of coral assemblages to thermal stress, both spatially and temporally, is essential to determine which reefs are more able to tolerate climate change. We compared variations in spatial and taxonomic patterns between two bleaching events at the scale of an island (Moorea Island, French Polynesia). Despite similar thermal stress and light conditions, bleaching intensity was significantly lower in 2007 (approximately 37 % of colonies showed signs of bleaching) than in 2002, when 55 % of the colonies bleached. Variations in the spatial patterns of bleaching intensity were consistent between the two events. Among nine sampling stations at three locations and three depths, the stations at which the bleaching response was lowest in 2002 were those that showed the lowest levels of bleaching in 2007. The taxonomic patterns of susceptibility to bleaching were also consistent between the two events. These findings have important implications for conservation because they indicate that corals are capable of acclimatization and/or adaptation and that, even at small spatial scales, some areas are consistently more susceptible to bleaching than others.

  16. Differential Response of Coral Assemblages to Thermal Stress Underscores the Complexity in Predicting Bleaching Susceptibility.

    Science.gov (United States)

    Chou, Loke Ming; Toh, Tai Chong; Toh, Kok Ben; Ng, Chin Soon Lionel; Cabaitan, Patrick; Tun, Karenne; Goh, Eugene; Afiq-Rosli, Lutfi; Taira, Daisuke; Du, Rosa Celia Poquita; Loke, Hai Xin; Khalis, Aizat; Li, Jinghan; Song, Tiancheng

    2016-01-01

    Coral bleaching events have been predicted to occur more frequently in the coming decades with global warming. The susceptibility of corals to bleaching during thermal stress episodes is dependent on many factors and an understanding of these underlying drivers is crucial for conservation management. In 2013, a mild bleaching episode ensued in response to elevated sea temperature on the sediment-burdened reefs in Singapore. Surveys of seven sites highlighted variable bleaching susceptibility among coral genera-Pachyseris and Podabacia were the most impacted (31% of colonies of both genera bleached). The most susceptible genera such as Acropora and Pocillopora, which were expected to bleach, did not. Susceptibility varied between less than 6% and more than 11% of the corals bleached, at four and three sites respectively. Analysis of four of the most bleached genera revealed that a statistical model that included a combination of the factors (genus, colony size and site) provided a better explanation of the observed bleaching patterns than any single factor alone. This underscored the complexity in predicting the coral susceptibility to future thermal stress events and the importance of monitoring coral bleaching episodes to facilitate more effective management of coral reefs under climate change.

  17. Differential Response of Coral Assemblages to Thermal Stress Underscores the Complexity in Predicting Bleaching Susceptibility.

    Directory of Open Access Journals (Sweden)

    Loke Ming Chou

    Full Text Available Coral bleaching events have been predicted to occur more frequently in the coming decades with global warming. The susceptibility of corals to bleaching during thermal stress episodes is dependent on many factors and an understanding of these underlying drivers is crucial for conservation management. In 2013, a mild bleaching episode ensued in response to elevated sea temperature on the sediment-burdened reefs in Singapore. Surveys of seven sites highlighted variable bleaching susceptibility among coral genera-Pachyseris and Podabacia were the most impacted (31% of colonies of both genera bleached. The most susceptible genera such as Acropora and Pocillopora, which were expected to bleach, did not. Susceptibility varied between less than 6% and more than 11% of the corals bleached, at four and three sites respectively. Analysis of four of the most bleached genera revealed that a statistical model that included a combination of the factors (genus, colony size and site provided a better explanation of the observed bleaching patterns than any single factor alone. This underscored the complexity in predicting the coral susceptibility to future thermal stress events and the importance of monitoring coral bleaching episodes to facilitate more effective management of coral reefs under climate change.

  18. Susceptibility of central Red Sea corals during a major bleaching event

    KAUST Repository

    Furby, Kathryn A.

    2013-01-04

    A major coral bleaching event occurred in the central Red Sea near Thuwal, Saudi Arabia, in the summer of 2010, when the region experienced up to 10-11 degree heating weeks. We documented the susceptibility of various coral taxa to bleaching at eight reefs during the peak of this thermal stress. Oculinids and agaricids were most susceptible to bleaching, with up to 100 and 80 % of colonies of these families, respectively, bleaching at some reefs. In contrast, some families, such as mussids, pocilloporids, and pectinids showed low levels of bleaching (<20 % on average). We resurveyed the reefs 7 months later to estimate subsequent mortality. Mortality was highly variable among taxa, with some taxa showing evidence of full recovery and some (e. g., acroporids) apparently suffering nearly complete mortality. The unequal mortality among families resulted in significant change in community composition following the bleaching. Significant factors in the likelihood of coral bleaching during this event were depth of the reef and distance of the reef from shore. Shallow reefs and inshore reefs had a higher prevalence of bleaching. This bleaching event shows that Red Sea reefs are subject to the same increasing pressures that reefs face worldwide. This study provides a quantitative, genus-level assessment of the vulnerability of various coral groups from within the Red Sea to bleaching and estimates subsequent mortality. As such, it can provide valuable insights into the future for reef communities in the Red Sea. © 2013 Springer-Verlag Berlin Heidelberg.

  19. Susceptibility of central Red Sea corals during a major bleaching event

    Science.gov (United States)

    Furby, K. A.; Bouwmeester, J.; Berumen, M. L.

    2013-06-01

    A major coral bleaching event occurred in the central Red Sea near Thuwal, Saudi Arabia, in the summer of 2010, when the region experienced up to 10-11 degree heating weeks. We documented the susceptibility of various coral taxa to bleaching at eight reefs during the peak of this thermal stress. Oculinids and agaricids were most susceptible to bleaching, with up to 100 and 80 % of colonies of these families, respectively, bleaching at some reefs. In contrast, some families, such as mussids, pocilloporids, and pectinids showed low levels of bleaching (reefs 7 months later to estimate subsequent mortality. Mortality was highly variable among taxa, with some taxa showing evidence of full recovery and some (e.g., acroporids) apparently suffering nearly complete mortality. The unequal mortality among families resulted in significant change in community composition following the bleaching. Significant factors in the likelihood of coral bleaching during this event were depth of the reef and distance of the reef from shore. Shallow reefs and inshore reefs had a higher prevalence of bleaching. This bleaching event shows that Red Sea reefs are subject to the same increasing pressures that reefs face worldwide. This study provides a quantitative, genus-level assessment of the vulnerability of various coral groups from within the Red Sea to bleaching and estimates subsequent mortality. As such, it can provide valuable insights into the future for reef communities in the Red Sea.

  20. Kekerasan mikro enamel gigi permanen muda setelah aplikasi bahan pemutih gigi dan pasta remineralisasi (Enamel micro hardness of young permanent tooth after bleaching and remineralization paste application

    Directory of Open Access Journals (Sweden)

    Budianto Liwang

    2014-12-01

    Full Text Available Background: Studies showed that bleaching agent had demineralization effect to enamel, and encourage use of remineralization paste after bleaching treatment especially in young permanent tooth which in post-eruptive enamel maturation. Purpose: The study ere aimed to determine the bleaching agent effect on enamel surface micro hardness, and to determine the effect of remineralization paste application on enamel surface micro hardness of young permanent tooth after bleaching treatment. Methods: Fourteen young permanent teeth were placed in a block of resin with a window on the buccal surface enamel. The initial enamel surface hardness was measured using Microvickers Hardness Tester. Then the application of hydrogen peroxide bleaching materials 30% was done three times for 15 minutes and followed by surface hardness of enamel measurement. Samples were divided into 2 groups; the first group was applied paste of Hydroxy apatite + NaF 1450ppm , and the second group was applied paste of CPP–ACP + NaF 900ppm. Each paste was applied for 30 minutes for 7 days, then the enamel surface hardness of samples were measured. Results: The enamel surface micro hardness decreased after bleaching from 333.09 ± 10.49 VHN to 299.15±5.70 VHN. Micro hardness after application of Hidroxy apatite + NaF 1450ppm was 316.61±5.87 VHN and after application of CPP-ACP + NaF 900ppm was 319.94±3.25 VHN, however the micro hardness still lower than initial micro hardness. Conclusion: Tooth bleaching agent caused a decrease of enamel surface micro hardness in young permanent tooth. The use of remineralization paste enabled to increase the enamel surface micro hardness young permanent tooth.Latar belakang: Penelitian-penelitian sebelumnya menunjukkan bahwa produk pemutih gigi memiliki efek demineralisasi enamel gigi, dan mendorong penggunaan pasta remineralisasi setelah pemutihan gigi terutama di gigi muda permanen yang enamelnya masih dalam proses maturasi pasca-erupsi. Tujuan

  1. Development of Bicarbonate-Activated Peroxide as a Chemical and Biological Warfare Agent Decontaminant

    Science.gov (United States)

    2006-06-30

    Peroxide (HOO-) 7.8 29 26.7 ± 0.2 t-Butyl hydroperoxide ((CH3)3COO-) 7.8 9.7 39 Cumene hydroperoxide ((C6H6)C(CH3)2OO-) 7.8 9.3 22 All reactions run with...peroxymonocarbonate ion (HCO4-) as the oxidant in the catalytic oxidation reactions . For perhydrolytic cleavage of organophosphates the peroxycarbonate dianion...solubility and reaction rates for applications in chemical warfare agent decontamination. -O *C O O OH -O *C OH O HO *C OH O *CO2 HO2 - H2OHO *C O O OH pKa

  2. In-vitro activity of 21 antimicrobial agents against Neisseria gonorrhoeae in Brussels.

    OpenAIRE

    Gordts, B; Vanhoof, R; Hubrechts, J M; Dierickx, R; Coignau, H; Butzler, J P

    1982-01-01

    The minimum inhibitory concentrations (MIC) of 21 antimicrobial agents was measured for 80 strains of Neisseria gonorrhoeae isolated in Brussels in 1978. Bimodal distributions were found for penicillin G, ampicillin, amoxycillin, carbenicillin, and cephalexin. Of the strains, 17.5% were relatively resistant to penicillin G (MIC greater than 0.08 microgram/ml) 27.5% to ampicillin (MIC greater than 0.16 microgram/ml), 23.8% to amoxycillin, and 43.3% to carbenicillin. Cefotaxime was the most act...

  3. Valorisation of by Products from Bleached Eucalyptus Kraft Pulp Mill

    Science.gov (United States)

    Silva, M. C.; Lopes, O. R.; Colodette, J. L.; Porto, A. O.; Rieumont, J.; Chaussy, D.; Belgacem, M. N.; Silva, G. G.

    2008-08-01

    Three industrial wastes arising from bleached hardwood kraft pulps, namely: unbleached screen rejects (USR), effluent treatment (ETW), and eucalyptus bark (EB) were analyzed with the aim of their possible valorization as an alternative source of cellulose. Their morphological properties were determined using MorFi apparatus. For this study the sample bleached kraft pulp, BKP, was analyzed as a reference. Lignin and carbohydrate contents were also quantified. These by-products were studied as such (i.e. without careful purification) because we intended to find rational and low-cost way of valorization. In fact any additional operation will induce an over cost. The results obtained indicate that these industrial wastes can be potential raw material in fibre-based applications (paper, composites…), since they contain a high proportion of cellulose with preserved fibrillar morphology. Some of these materials have low lignin and inorganic residue contents.

  4. THE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    YumengZhao; ShuhuiYang; LiangSheng; YonghaoNi

    2004-01-01

    Hydrogen peroxide bleaching has been extensivelyused in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed underalkaline condition, especially when transition metalions exit. Experiments show that the valence oftransition metal ion is also responsible for thedecomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ andFe3+. They are both catalytically active to hydrogenperoxide decomposition. Because Fe3+ is brown, itcan affect the brightness of pulp directly, it can alsocombine with phenol, forming complexes which notonly are stable structures and are difficult to beremoved from pulp, but also significantly affect thebrightness of pulp because of their color.Sodium silicate and magnesium sulfate, when usedtogether, can greatly decrease hydrogen peroxidedecomposition. The optimum dosage of sodiumsilicate is about 0.1% (on solution) for Fe2~ and0.25% (on solution) for Fe3~. Adding chelants such asDTPA or EDTA with stabilizers simultaneously canobviously improve pulp brightness. For iron ions, thechelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite andcellulose can reduce Fe3+ to Fez+ effectively, and pulpbrightness is improved greatly. Adding sodiumthiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxidesolution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxidebleaching, the optimum pH value should be 10.5-12.

  5. Synthesis and biological activity of quaternary ammonium salt-type agents containing cholesterol and terpenes.

    Science.gov (United States)

    Novotná, Eva; Waisser, Karel; Kuneš, Jiří; Palát, Karel; Buchta, Vladimír; Stolaříková, Jiřina; Beckert, Rainer; Wsól, Vladimír

    2014-06-01

    New quaternary ammonium salt-type compounds with lipophilic cholesterol and terpene moieties were synthesized. The compounds showed promising antibacterial and antimycobacterial activities. Those compounds containing the cholesterol moiety showed significant activity against Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecium. On the contrary, the antimycobacterial activity increased with the presence of the terpene unit in the molecule.

  6. KINETICS OF DELIGNIFICATION AND CARBOHYDRATE DEGRADATION DURING OXYGEN BLEACHING

    Institute of Scientific and Technical Information of China (English)

    K.LNguyen

    2004-01-01

    Carbohydrate degradation during oxygen bleaching isassociated with cleavage reactions. It is apparent thatthe loss of the cellulose DPis strongly affected by(degree ofpolymisation) the extent of thedelignification. A strong linear correlation can beestablished between the DP of cellulose chains andthe residual lignin in the pulp. The Nuclear Growthconcept and Percolation Theory for heterogenoussystem can be combined to formulate kinetic modelsfor both the delignification and the degradation ofcarbohydrate. The models prediction is statisticallyrobust and can be applied to different pulps atdifferent bleachin~ conditions.