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Sample records for activated bleaching earth

  1. 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)

  2. A bleaching earth from egyptian local deposits

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    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

  3. Bleaching earth clay (pH 12.5: A novel and reusable catalyst for rapid synthesis of 7-Hydroxy 4-Styryl coumarin derivatives and their antihelmintic activity

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    Rahul D. Kamble

    2013-06-01

    Full Text Available 7-hydroxy 4-styryl coumarin derivatives were synthesized by Knovengel condensation of 7-hydroxy 4-methyl coumarin with aldehydes by using novel and reusable catalyst bleaching earth clay (pH12.5 in PEG-400 as green reaction solvent, followed by the Mannich reaction. The synthesized compounds were evaluated for their in vitro antihelmintic activity and it was found that the synthesized compounds showed good antihelmintic activity.

  4. Efficient production of fatty acid methyl ester from waste activated bleaching earth using diesel oil as organic solvent.

    Science.gov (United States)

    Kojima, Seiji; Du, Dongning; Sato, Masayasu; Park, Enoch Y

    2004-01-01

    Fatty acid methyl ester (FAME) production from waste activated bleaching earth (ABE) discarded by the crude oil refining industry was investigated using fossil fuel as a solvent in the esterification of triglycerides. Lipase from Candida cylindracea showed the highest stability in diesel oil. Using diesel oil as a solvent, 3 h was sufficient to obtain a yield of approximately 100% of FAME in the presence of 10% lipase from waste ABE. Kerosene was also a good solvent in the esterification of triglycerides embedded in the waste ABE. Fuel analysis showed that the FAME produced using diesel oil as a solvent complied with the Japanese diesel standard and the 10% residual carbon amount was lower than that of FAME produced using other solvents. Use of diesel oil as solvent in the FAME production from the waste ABE simplified the process, because there was no need to separate the organic solvent from the FAME-solvent mixture. These results demonstrate a promising reutilization method for the production of FAME, for use as a biodiesel, from industrial waste resources containing waste vegetable oils.

  5. Lipase-catalyzed biodiesel production from waste activated bleaching earth as raw material in a pilot plant.

    Science.gov (United States)

    Park, Enoch Y; Sato, Masayasu; Kojima, Seiji

    2008-05-01

    The production of fatty acid methyl esters (FAMEs) from waste activated bleaching earth (ABE) discarded by the crude oil refining industry using lipase from Candida cylindracea was investigated in a 50-L pilot plant. Diesel oil or kerosene was used as an organic solvent for the transesterification of triglycerides embedded in the waste ABE. When 1% (w/w) lipase was added to waste ABE, the FAME content reached 97% (w/w) after reaction for 12 h at 25 degrees C with an agitation rate of 30 rpm. The FAME production rate was strongly dependent upon the amount of enzyme added. Mixtures of FAME and diesel oil at ratios of 45:55 (BDF-45) and 35:65 (BDF-35) were assessed and compared with the European specifications for biodiesel as automotive diesel fuel, as defined by pr EN 14214. The biodiesel quality of BDF-45 met the EN 14214 standard. BDF-45 was used as generator fuel, and the exhaust emissions were compared with those of diesel oil. The CO and SO2 contents were reduced, but nitrogen oxide emission increased by 10%. This is the first report of a pilot plant study of lipase-catalyzed FAME production using waste ABE as a raw material. This result demonstrates a promising reutilization method for the production of FAME from industrial waste resources containing vegetable oils for use as a biodiesel fuel.

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

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    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

  7. Value-added products from spent bleaching earth

    International Nuclear Information System (INIS)

    Loh Soh Kheang; Muzammil Ngatiman; James, Stephen

    2010-01-01

    Full text: Bleaching earth is used in the bleaching process of physical refining of palm oil to remove color, phospholipids, residue gums, oxidized products and any trace metals from the oil. These colored pigments are trapped and absorbed in the bleaching earth, thus transforming the originally whitish earth to dark grey and is, from then, named spent bleaching earth (SBE). SBE is considered as an industrial by-product as there is hardly any practical application for it. Large quantity of SBE is commonly disposed of in landfills, which poses potential hazards to environment. New economical ways in utilizing it is sought to eliminate the problem arises from its disposal. This paper presents a study on the possibility of developing a soil conditioner using enhanced SBE as the base material. The study found that there are certain attributes observed in the enhanced SBE that could be of advantages for SBE to become a good soil conditioner. The enhanced SBE contains organic matters and about 18-20 % of residue oil which exhibits good water holding capacity in slow release of water, and enriched nutrient content for plant nutrient uptake. (author)

  8. Spent Bleaching Earth as a Pozzolanic Material | Muthengia ...

    African Journals Online (AJOL)

    This paper proposes a cementing material from spent bleaching earth (SBE). SBE consists mainly of residual oil and ... The setting time of a workable paste of the ashed SBE-lime material was well within the Kenya standard 02 1263 requirements for Portland pozzolana cements. Key words: Cement, pozzolana, Spent ...

  9. CO2capture 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

    CO 2 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 CO 2 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 CO 2 capture capacity, but this was decreased with excess MEA loading (>30wt.%). At a 10% (V/V) initial CO 2 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 CO 2 capacity due to the blocking effect of the excess moisture on the sorbent surface. However, SAB-30 could completely capture CO 2 even in a 100% (V/V) initial CO 2 concentration feed. A maximum CO 2 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 CO 2 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 CO 2 capture process and the heterogeneous adsorption surface of SAB-30. Thermodynamics studies revealed that CO 2 capture on the bifunctional SAB-30 is feasible, spontaneous and exothermic in nature. Copyright © 2016. Published by Elsevier B.V.

  10. Physicochemical properties and oxidative stability of bleached pomace-olive oil on Tunisian activated clays

    International Nuclear Information System (INIS)

    Jahouach, Wafa

    2002-01-01

    This work is a contribution to studying bleaching process, which is an important stage in refining of vegetable oils. This process permitted to reduce or convert undesired constituents to harmless ones from oils and fats. Virgin olive oil, considered as reference, and pomace-olive oil were bleached in optimal conditions using Tunisian activated clays ( collected from the South of Tunisia) which were prepared in our laboratory and compared with commercial bleaching earths. It was shown that activated Tunisian clays are characterized by a very important adsorptive capacity, which is similar to that of commercial ones. In addition, the study of physicochemical properties of bleached oils was considered. The fatty acid composition (GC), the triacylglycerol composition (HPLC), and oxidative stability (UV spectrometry) allowed to conclude that treated oils do not undergo considerable physicochemical alterations and their caracteristics remain in concordance with international standards relative to edible refined oils. (Author)

  11. Kinetics and thermodynamics of aqueous Cu(II adsorption on heat regenerated spent bleaching earth

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    Enos W. Wambu

    2011-08-01

    Full Text Available This study investigated the kinetics and thermodynamics of copper(II removal from aqueous solutions using spent bleaching earth (SBE. The spent bleaching earth, a waste material from edible oil processing industries, was reactivated by heat treatment at 370 oC after residual oil extraction in excess methyl-ethyl ketone. Copper adsorption tests were carried out at room temperature (22±3 oC using 5.4 x 10-3C M metal concentrations. More than 70% metal removal was recorded in the first four hours although adsorption continued to rise to within 90% at 42 hours. The pH, adsorbent dosage and initial concentrations were master variables affecting RSBE adsorption of Cu(II ions. The adsorption equilibrium was adequately described by the Dubinin-Radushkevich (D-R and the Temkin isotherms and the maximum sorption capacity derived from the D-R isotherm was compared with those of some other low cost adsorbents. The adsorption process was found to follow Lagergren Pseudo-second order kinetics complimented by intra-particle diffusion kinetics at prolonged periods of equilibration. Based on the D-R isotherm adsorption energy and the thermodynamic adsorption free energy ∆G, it was suggested that the process is spontaneous and based on electrostatic interactions between the metal ions and exposed active sites in the adsorbent surface.

  12. 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.

  13. Alteration of chemical composition and the oxidative stability of bleached pomace-olive oil on activated clays.

    Science.gov (United States)

    Jahouach, W; Essid, K; Trabelsi, M; Frikha, M H

    2006-09-20

    This work is a contribution to the study of the bleaching process, which is a very important stage in the refining process of vegetable oils and used to reduce or convert undesired constituents to harmless ones from fats and oils. The virgin olive oil, taken as reference, and the pomace-olive oil were bleached in the optimal conditions using Tunisian bleaching earths (South of Tunisia) which were activated in our laboratory and compared with commercial clays. It was shown that activated Tunisian clays are characterized by a very important adsorptive capacity, comparable to that of commercial clays. Also, the physicochemical stability of bleached oils was studied. The fatty acid composition (GC), the triacylglycerol composition (HPLC), and the oxidative stability (UV spectrometry) allowed us to conclude that oils, bleached with the Tunisian activated clays, do not undergo considerable physicochemical alterations and remain corresponding to the international standards for refined oils for human consumption.

  14. Formulation of a grease from spent bleaching earth, waste cooking oil and fumed silica as additives

    International Nuclear Information System (INIS)

    Mohd Khairul Nizam Mohd Zuhan; Hayder Abdul Bari

    2010-01-01

    The study is to formulate new multi-purpose grease from industrial wastes. In this study we intent to use waste cooking oil and spent bleaching earth as a main ingredients for the grease formulation. Additives such as fumed silica, molybdenum disulphide and other type of additives are introduced to improve the properties of the grease. The best percentage of waste cooking oil, spent bleaching earth and additives added is determined (w/w) during this study to produces the best consistency through penetration test based on NGLI standard. Other properties being determined include drop point, oxidation stability, and oil separation test through ASTM method. From result obtained, some necessary modification and additives addition into spent bleaching earth and waste cooking oil can produce new multi-purpose based grease that can be commercialized. (author)

  15. Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

    Science.gov (United States)

    Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

    2009-09-01

    To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoom activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.

  16. A Comparison Between Alkali Peroxide and Activated Peroxide Processes in Bleaching Hardwoods Chemi-mechanical Pulp

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    Farhad Zeyni

    2013-06-01

    Full Text Available Unbleached chemi-mechanical pulp of 85% pulp yield and produced from hornbeam, beech and populus woods respectively by 3:1:1 ratio, was used for peroxide bleaching. Two bleaching systems, alkali peroxide (conventional bleaching and activated peroxide by TAED activator, were used for pulp bleaching. Bleaching treatments included different percentages of hydrogen peroxide and caustic soda consumption. In this research, the hydrogen peroxide consumption rate, pulp yield, process selectivity, bleached pulp brightness and bleaching effluent pollution load (COD were investigated. Results showed that, brightness values were increased by bleach chemicals charge rising, in both bleaching systems, but the increasing trend was downward. Also, pulp yield was decreased by increase of chemical charges, but residual peroxide was raised. The activated peroxide process compare to conventional process had lower efficiency and brightness improvement values of pulp were less than those of alkali peroxide process. But pulp yield and effluent pollution load was less by activated peroxide bleaching.

  17. IDENTIFIKASI DAN UJI POTENSI BAKTERI LIPOLITIK DARI LIMBAH SBE (SPENT BLEACHING EARTH SEBAGAI AGEN BIOREMEDIASI

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    Fitralia Elyza

    2016-03-01

    Full Text Available Limbah minyak kelapa sawit yang terbanyak adalah SBE (Spent Bleaching Earth, limbah ini mengandung residu minyak tinggi yang dapat mencemari lingkungan, 30% residu minyak pada limbah SBE dapat digunakan bakteri untuk pertumbuhannya, sehingga adanya bakteri mampu menjadi agen bioremediasi pencemaran SBE. Penelitian dilakukan untuk mendapatkan bakteri lipolitik sebagai agen potensial bioremediasi pada limbah SBE. Metode pengambilan sampel limbah SBE secara random sampling. Sampel tanah diambil secara acak dari beberapa titik area limbah SBE. Bakteri diisolasi dari sampel limbah SBE, kemudian dilakukan tahapan yaitu : pemurnian, seleksi, uji potensi, bakteri berpotensi mereduksi lipid dikarakterisasi dan diidentifikasi genusnya. Hasil penelitian menunjukkan bahwa Aktivitas enzim lipase yang tinggi menandakan bahwa bakteri lipolitik bekerja optimal merombak zat pencemar. Bakteri yang memiliki potensi sebagai agen bioremediasi terdiri dari genus Citrobacter (B1, Enterobacter (B2 dan Acinetobacter (B3. The most palm oil waste is SBE (Spent Bleaching Earth, this waste had many reduced lipid that got pollution for inviroments, Bacteria can use lipid from SBE as much as 30% for growed. So that consist of bacteria in SBE as a potensial agent for remediation. This study aims to obtain lipolytic bacteria as a potential agent of bioremediation. The method of sampling soil were taken at random from SBE waste, Bacteria were isolated from the SBE waste, then they were selected into steps : performed purification, selection, potential test, then characterized and identified it’s genus of potential bacteria. The results showed that the higest activity enzyme of lipolytic indicated that the lipolytic bacteria worked optimal for reduce polution. Bacteria had potential as a bioremediation agent consisting of genus Citrobacter (B1, Enterobacter (B2 and Acinetobacter (B3.

  18. In Situ Biodiesel Production from Residual Oil Recovered from Spent Bleaching Earth

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    Ramli Mat

    2011-05-01

    Full Text Available Currently, semi-refined and refined vegetable oils are used as a feedstock in biodiesel production. However, due to competition with conventional fossil fuel, economic reasons, shortage supply of food and its social impact on the global scale has somewhat slowed the development of biodiesel industry. Studies have been conducted to recover oil from mill palm oil operation especially from the spent bleaching earth. Hence, the study was to investigate the potential recovery of oil from spent bleaching earth to be used as a feedstock for biodiesel production. The effect of different types of catalysts (sodium hydroxide alkali and sulfuric acid catalysts on biodiesel yield was studied. In addition, the effect of volume addition of methanol to the weight of spent bleaching earth on the product yield was also studied. Furthermore, the effect of ratio of hexane to methanol was also carried out to determine its product yield. The studies were carried out in an in-situ biodiesel reactor system and the biodiesel product was analyzed using gas chromatography mass spectrometry. Result shows that the use of alkali catalyst produced the highest yield of biodiesel and the most optimum biodiesel yield was obtained when the methanol to spent bleaching earth ratio was 3.2:1 (gram of methanol: gram of SBE and hexane to methanol ratio of 0.6:1 (volume of hexane: volume of methanol. © 2011 BCREC UNDIP. All rights reserved(Received: 19th December 2010, Revised: 10th May 2011; Accepted: 18th May 2011[How to Cite: R. Mat, O.S. Ling, A. Johari, M. Mohamed. (2011. In Situ Biodiesel Production from Residual Oil Recovered from Spent Bleaching Earth. Bulletin of Chemical Reaction Engineering & Catalysis, 6(1: 53-57. doi:10.9767/bcrec.6.1.678.53-57][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.678.53-57 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/678 ] | View in 

  19. Bond strength of resin composite to light activated bleached enamel

    African Journals Online (AJOL)

    2015-09-02

    Sep 2, 2015 ... Conclusion: The various irradiation treatments following the application of the whiteness HP bleaching agent to enamel did not significantly reduce the µTBS within a 14‑day period. Key words: Bleaching agents, lasers, lasers neodymium: yttrium aluminum garnet, resin bonding, tooth bleaching. Date of ...

  20. PREPARATION OF SPENT BLEACHING EARTH-SUPPORTED CALCIUM FROM LIMESTONE AS CATALYST IN TRANSESTERIFICATION OF WASTE FRYING OIL

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    Noor Hindryawati

    2017-06-01

    Full Text Available An investigation was conducted on palm oil refinery waste-spent bleaching earth (POR-SBE, POR-SBE supported by calcium as catalysts for methyl esters production through transesterification process using waste frying oil. The catalysts showed longer lasting activity than the traditional alkali catalysts. The optimum conditions for the process were: Ca-POR-SBE catalyst amount 7 %; methanol to oil molar ratio 12:1; and a reaction duration is 4 h. The process was able to transesterify oil to methyl esters at 96.8 % conversion at 65 °C. The catalysts were easily separated from the reaction mixture and the final product met selected biodiesel fuel properties in accordance with European Standard EN 14214.

  1. Bleaching of Neutral Cotton Seed Oil Using Organic Activated Carbon in a Batch System: Kinetics and Adsorption Isotherms

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    Abba Chetima

    2018-03-01

    Full Text Available In the processing of cotton and neem seeds to obtain oil for diverse uses, enormous quantities of seed husk are generated as waste, which when not properly disposed of, poses environmental problems. One way of reducing this waste is to use it for the production of activated carbon (AC for its multiple applications. In this work, activated carbon was produced from cotton and neem seed husks by carbonization followed by acid activation. The prepared ACs were characterized for its porosity and surface properties as well as for its ability to bleach neutral cotton seed oil. The prepared ACs are very efficient in the decoloration process, as they removed about 96–98% of the pigments compared to 98.4% removal with commercial bleaching earth. Temperature had a pronounced effect on the bleaching of neutral cotton seed oil. Maximum adsorption was observed at 60 °C for a contact time of 45 min. The adsorption kinetics were modelled by the intra-particle and the pseudo-second order equations while the adsorption isotherms followed the Langmuir and Freundlich equations. It is concluded that the organic ACs are efficient in pigment removal from neutral cotton seed oil and therefore are potential bleaching agents for the vegetable oil industry.

  2. Optimization of acid-activated bentonites on bleaching of cotton oil

    International Nuclear Information System (INIS)

    Lacin, O.; Sayan, E.; Kirali, E.G.

    2013-01-01

    Bentonites are commonly used adsorbent on bleaching cotton oil to produce edible oil products. Bleaching capacities of neutralized cotton oil were investigated with acid-activated Arguvan and Kursunlu bentonites. Two models for acid activation of the bentonites were developed by using a full factorial experimental design and central composite design. The parameters used to develop these models were contact time, solid to liquid ratio, acid concentration and moisture of bentonite. By using a constrained optimization program, the maximum bleaching capacities of neutralized cotton oil were determined as 99.99% and 48.5% for Arguvan and Kursunlu, respectively. Optimum results showed that Turkish bentonites (especially Arguvan bentonite) have high bleaching ability and they can be used efficiently to bleach neutralized cotton oil by considering the favorable volume weight, capacity of oil adsorbed and filtration rate. (author)

  3. Influence of bleach activators on the fabric made from cotton (gossypium hamster l.)

    International Nuclear Information System (INIS)

    Asif, H.M.; Iftikhar, M.; Shahbaz, B.

    2013-01-01

    Raw cotton contains various type of trash and most of the impurities are removed during the spinning process but still the cotton fabric coming from the weaving or knitting process always contains some impurities. Some time cotton fabric gets the oil, stains and coloured materials which affect the quality of dyed fabric. Bleaching is a process that eliminates unwanted coloured matters from the fibres, yarn and fabrics. A bleaching agent is a material that lightens or whitens a substrate through chemical action. Hydrogen peroxide is by far the most commonly used oxidative bleaching agent for cotton and its blends, accounting for more than 90 percent of all the bleaching agents. The use of activators to enhance the bleaching performance of hydrogen peroxide for cellulosic materials has gained popularity now a day. In this context the main objectives of this paper are to study the influence of different bleaching activators on cotton fabric and to give implications for textile extension.The results indicate that the activators with different concentrations, along with different concentrations of hydrogen peroxide (H/sub 2/O/sub 2) have significant influence on the bleaching performance of cotton fabric. (author)

  4. Different light-activated in-office bleaching systems: a clinical evaluation.

    Science.gov (United States)

    Gurgan, Sevil; Cakir, Filiz Yalcin; Yazici, Esra

    2010-11-01

    The aim of this clinical study was to evaluate the efficiency of in-office bleaching systems with different light sources for color change and possible side effects such as tooth sensitivity and gingival irritations. Forty healthy volunteers aged 18 years and older (average age 27.3 years), having all their natural healthy teeth in shade A3 or darker on the Vita shade guide, with no restorations on the buccal surfaces and no tooth sensitivity, participated in this study. Participants were randomly assigned to four groups of ten volunteers. Group 1 received bleaching without light activation (Opalescence Xtra Boost, Ultradent); group 2 received bleaching (Laser White 10, Biolase) with a diode laser (810 nm, 10 W/ Laser Smile, Biolase) activation; group 3 received bleaching treatment (Remewhite, Remedent) with a plasma arc lamp (400-490 nm, 2800 mV/cm(2), Remecure CL15), and group 4 received bleaching with a light emitting diode (LED) lamp (By White accelerator, Ensodent) according to the manufacturers' recommendations. The shade was assessed with a classical Vita shade guide (Vita Zahnfabrik) and a digital spectrophotometer (Vita Easy Shade, Vident). The color of teeth was scored at baseline and 1 week after bleaching. Any side effects on teeth or gingiva was recorded by visual analog scale. Results were analyzed statistically, by one-way analysis of variance (ANOVA), Kruskal-Wallis, and Mann-Whitney U tests with Bonferroni correction. All the bleaching techniques resulted in shade change. No significant differences were found in the color change among the four groups with shade guide assessment (P > 0.05), but spectrophotometer readings exhibited significant differences among the groups (P < 0.05). The overall shade change values expressed as DeltaL, Deltaa, Deltab, DeltaE for group 2 was significantly higher than those for the other groups (P < 0.05). Group 2 also showed lower tooth and gingival sensitivity scores than those of the other groups (P < 0.05). All

  5. Production and characterization of biodiesel using palm kernel oil; fresh and recovered from spent bleaching earth

    Directory of Open Access Journals (Sweden)

    Abiodun Aladetuyi

    2014-12-01

    Full Text Available Palm kernel oil (PKO was recovered from spent bleaching earth with a yield of 16 %, using n-hexane while the fresh oil was extracted from palm kernel with n-hexane and a yield of 40.23% was obtained. These oils were trans-esterified with methanol under the same reaction conditions: 100 oC, 2 h reaction time, and oil-methanol ratio of 5:1 (w/v. The cocoa pod ash (CPA was compared with potassium hydroxide (KOH as catalyst. The percentage yields of biodiesel obtained from PKO catalysed by CPA and KOH were 94 and 90%, respectively. While the yields achieved using the recovered oil catalysed by CPA and KOH were measured at 86 and 81.20 %. The physico-chemical properties of the biodiesel produced showed that the flash point, viscosity, density, ash content, percentage carbon content, specific gravity and the acid value fell within American Society for Testing and Materials (ASTM specifications for biodiesel. The findings of this study suggest that agricultural residues such as CPA used in this study could be explored as alternatives for KOH catalyst for biodiesel production.

  6. Cementing Material From Rice Husk-Broken Bricks-Spent Bleaching Earth-Dried Calcium Carbide Residue

    Directory of Open Access Journals (Sweden)

    Muthengia Jackson Washira

    2012-10-01

    Full Text Available A cementious material, coded CSBR (Carbide residue Spent bleaching earth Broken bricks and Rice husks, was made from dried calcium carbide residue (DCCR and an incinerated mix of rice husks (RH, broken bricks (BB and spent bleaching earth (SBE. Another material, coded SBR (Spent bleaching earth Broken bricks and Rice husk ash, was made from mixing separately incinerated RH, SBE and ground BB in the same ash ratio as in CSBR. When CSBR was inter-ground with Ordinary Portland Cement (OPC, it showed a continued decrease in Ca(OH2 in the hydrating cement as a function of curing time and replacement levels of the cement. Up to 45 % replacement of the OPC by CSBR produced a Portland pozzolana cement (PPC material that passed the relevant Kenyan Standard. Incorporation of the CSBR in OPC reduces the resultant calcium hydroxide from hydrating Portland cement. The use of the waste materials in production of cementitious material would rid the environment of wastes and lead to production of low cost cementitious material.

  7. Effects of Light Activation, Agent Concentration, and Tooth Thickness on Dental Sensitivity After Bleaching

    OpenAIRE

    Moncada, G.; Sepulveda, D.; Elphick, K.; Contente, M.; Estay, J.; Bahamondes, V.; Fernandez, E.; Oliveira, O. B. [UNESP; Martin, J.

    2013-01-01

    Examining three bleaching systems, this in vivo clinical trial evaluated the relationship among tooth sensitivity, light activation, and agent concentration, and it correlated dental sensitivity with tooth thickness.Materials and Methods: Eighty-seven volunteer patients were included. Inclusion criteria were the presence of anterior teeth without restorations as well as the absence of a previous bleaching experience and absence of non-carious cervical lesions or dental pain. Exclusion criteri...

  8. Effect of bleaching on mercury release from amalgam fillings and antioxidant enzyme activities: a pilot study.

    Science.gov (United States)

    Cakir, Filiz Yalcin; Ergin, Esra; Gurgan, Sevil; Sabuncuoglu, Suna; Arpa, Cigdem Sahin; Tokgoz, İlknur; Ozgunes, Hilal; Kiremitci, Arlin

    2015-01-01

    The aim of this pilot clinical study was to determine the mercury release from amalgam fillings and antioxidant enzyme activities (Superoxide Dismutase [SOD] and Catalase[CAT] ) in body fluids after exposure to two different vital tooth bleaching systems. Twenty eight subjects with an average age of 25.6 years (18-41) having at least two but not more than four Class II amalgam fillings on each quadrant arch in the mouth participated in the study. Baseline concentrations of mercury levels in whole blood, urine, and saliva were measured by a Vapor Generation Accessory connected to an Atomic Absorption Spectrometer. Erythrocyte enzymes, SOD, and CAT activities in blood were determined kinetically. Subjects were randomly assigned to two groups of 14 volunteers. Group 1 was treated with an at-home bleaching system (Opalescence PF 35% Carbamide Peroxide, Ultradent), and Group 2 was treated with a chemically activated office bleaching system (Opalescence Xtra Boost 38% Hydrogen Peroxide, Ultradent) according to the manufacturer's recommendations. Twenty-four hours after bleaching treatments, concentrations of mercury and enzymes were remeasured. There were no significant differences on mercury levels in blood, urine, and saliva before and after bleaching treatments (p > 0.05). No differences were also found in the level of antioxidant enzyme activities (SOD and CAT) before and after treatments (p > 0.05). Mercury release did not affect the enzyme activities (p > 0.05). Bleaching treatments either office or home did not affect the amount of mercury released from amalgam fillings in blood, urine, and saliva and the antioxidant-enzyme activities in blood. Bleaching treatments with the systems tested in this pilot study have no deleterious effect on the mercury release from amalgam fillings and antioxidant enzymes in body fluids. © 2014 Wiley Periodicals, Inc.

  9. Clinical efficacy of a bleaching system based on hydrogen peroxide with or without light activation.

    Science.gov (United States)

    Calatayud, Jesús Oteo; Calatayud, Carlos Oteo; Zaccagnini, Alvaro Oteo; Box, Ma José Calvo

    2010-01-01

    The objective of the present study was to assess the clinical efficacy of a dental bleaching system based on hydrogen peroxide with or without light activation. This randomized controlled trial evaluated the effect of the light when applied to the hydrogen peroxide by using a split-mouth design with 21 patients, with light activation in one hemi-arch but not in the other. The bleaching agent was QuickWhite 35% hydrogen peroxide and activation was conducted with a diode lamp (Luma Cool). The Classic Vita Guide was used to score tooth shades. Two consecutive applications of hydrogen peroxide were made to one hemi-arch, each light-activated for 10 min. The other hemi-arch was then identically treated but without light activation. After removal of the bleaching agent, the shade was re-scored and the Wilcoxon signed ranks test was used to compare differences in tooth shade values. The bleaching treatment produced significant shade changes (P < 0.01) in both hemi-arches. After treatment, there were no statistically significant differences between light-treated and non-light-treated tooth types (central incisors, lateral incisors, and canines). However, taking central incisor, lateral incisor, and canine as a group, comparison between each hemi-arch showed a significant effect in the hemi-arch with light activation (P < 0.05). The use of diode light with a 35% hydrogen peroxide gel slightly improved the dental bleaching.

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

    Directory of Open Access Journals (Sweden)

    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

  11. PENGARUH DOSIS BLEACHING EARTH DAN WAKTU PEMUCATAN CRUDE PALM OILYANG BERVARIASI DETERIORATION OF BLEACHABILITY INDEX (DOBI TERHADAP MUTU PRODUK

    Directory of Open Access Journals (Sweden)

    Hasrul Abdi Hasibuan

    2017-07-01

    Full Text Available Deterioration of bleachability index (DOBI is one of the parameters in the refining process, to meet the quality of commercial crude palm oil (CPO; Miixing between high quality CPO and low quality CPO sometimes were undertaken. This study was conducted to assess the effect of dose of bleaching earth (BE and time of bleaching process of various CPO quality, especially CPOs that had different DOBIs. The raw materials used were CPO with DOBIs of 0.65 to 4.80 which obtained from different raw materials, namely of fresh fruit bunches (FFB, palm oil mill (POM, waste from POM, and CPO from FFB heated at 120°C (during 30 and 60 minutes and mixed with low quality CPO (ratio of 6:4 and 1:9. CPOs were bleached using BE doses of 0.5%, 1.0%, 2.5%, and 2% and time for 15, 30, 45, and 60 minutes. The results obtained from preparation of raw materials were CPO with DOBI of 3.9 and 4.8 (CPO from FFB 1 and 2, 1.4 and 2.68 (CPO from POM 1 and 2 and 0.85 (CPO from waste POM 2 as well as 2.5 and 0.65 (heating and 2.92 and 1.52 (mixing. The warming of CPO caused colour, carotene, and water content decreased, while free fatty acids (FFA and peroxide value (PV increased. The more CPO low quality mixed to CPO high quality caused carotene and DOBI decreased while colour, moisture content, FFB, and PV increased. The results of bleaching showed that increasing time and dose of BE caused colour, carotene, DOBI, and water contents decreased, while FFA increased. PV decreased with increasing doses of BE and for 30 minutes PV decreased then increased with increasing time. Bleaching process of CPO from mixing between high quality CPO and low quality CPO might increase FFA, despite the mixture resulted CPO had high DOBI. This would impact on the deodorization process.

  12. Biodiesel Production from Residual Palm Oil Contained in Spent Bleaching Earth by In Situ Trans-Esterification

    Directory of Open Access Journals (Sweden)

    A S Fahmil QRM

    2014-06-01

    Full Text Available Spent Bleaching Earth (SBE is an industrial solid waste of vegetable oil industry that has a high residual oil to be potentialy converted to biodiesel. This study aims at developing a biodiesel production process technology by utilizing residual palm oil contained in SBE and to test the use of hexane in the trans-esterification process. Optimization process was done by using the Response Surface Method (RSM. The variables studied included catalyst concentration and reaction time. On the other hand, the deoiled SBE resulted from biodiesel production was tested as an adsorbent on biodiesel purification after being reactivated. The method used in the biodiesel production included an in situ acid catalysed esterification followed by in situ base catalysed trans-esterification. The results of RSM showed that the optimum process was obtained at NaOH concentration of 1.8% and reaction time of 104.73 minutes, with a predicted response rate of 97.18% and 95.63% for validation results. The use of hexane could also increase the yield of biodiesel which was obtained on the ratio of hexane to methanol of 0.4:1 (volume of hexane: volume of methanol. On the other hand, the reactivated bleaching earth was effective as an adsorbent in biodiesel production, which was still conform with the Indonesian National Standard.

  13. Efficacy of tooth bleaching with and without light activation and its effect on the pulp temperature: an in vitro study.

    Science.gov (United States)

    Hahn, Petra; Schondelmaier, Nina; Wolkewitz, Martin; Altenburger, Markus Jörg; Polydorou, Olga

    2013-01-01

    The aim of this in vitro study was to evaluate the colour stability of bleaching after light activation with halogen unit, laser, LED unit or chemical activation up to 3 months after treatment. Four groups of teeth (n = 20) were bleached with Opalescence Xtra Boost (38% hydrogen peroxide) using four different methods: activation with halogen, LED, laser or chemical activation only. All teeth were bleached in one session for four times (4 × 15 min) and the colour was evaluated using a spectrophotometer at the following time points: before bleaching, immediately after bleaching, 1 day, and 1 and 3 months after the end of bleaching. Between the tested time points, the teeth were stored in 0.9% NaCl solution. Additionally, the temperature increase in the pulp chamber was measured using a measuring sensor connected to a computer. Bleaching with the halogen unit showed the highest colour change. Halogen unit, laser and chemical activation resulted in whiter teeth after 1 and 3 months compared to the colour after the end of the bleaching procedure (p ≤ 0.05). Three months after the end of bleaching, the shade changes observed were-halogen: 7.1 > chemical activation: 6.2 > LED: 5.4 > laser: 5.2. Halogen showed the highest temperature increase (17.39°C ± 1.96) followed by laser (14.06°C ± 2.55) and LED (0.41°C ± 0.66) (p light activation did not show any advantages compared to chemical bleaching. Although halogen unit showed the higher shade's change, its use resulted also in the higher pulp temperature. According to the present findings, light activation of the bleaching agent seems not to be beneficial compared to bleaching without light activation, concerning the colour stability up to 3 months after bleaching and the pulp temperature caused during the bleaching procedure.

  14. An active recombinant cocoonase from the silkworm Bombyx mori: bleaching, degumming and sericin degrading activities.

    Science.gov (United States)

    Unajak, Sasimanas; Aroonluke, Suradet; Promboon, Amornrat

    2015-04-01

    Cocoonase is a serine protease produced by silk moths and used for softening the cocoons so that they can escape. Degumming is one of the important steps in silk processing. This research aimed to produce an active recombinant Bombyx mori cocoonase (BmCoc) for the silk degumming process. A recombinant BmCoc was successfully expressed in a Pichia pastoris system. The purified enzyme showed specific activity of 227 U mg(-1) protein, 2.4-fold purification, 95% yield and a molecular weight of 26 kDa. The enzyme exhibited optimal temperature at 40 °C and optimal pH at 8, and showed thermal stability at 25-45 °C and pH stability at 5-9. The recombinant enzyme exhibited sericin degumming ability and color bleaching characteristics, and did not affect the fibroin fiber. The enzyme also degraded sericin substrate with a product size about 30-70 kDa. In this study, we successfully produced the active recombinant BmCoc in P. pastoris with promising functions for the Thai silk degumming process, which includes degumming, sericin degrading and color bleaching activities. Our data clearly indicated that the recombinant enzyme had proteolytic activity on sericin but not on fibroin proteins. The recombinant BmCoc has proven to be suitable for numerous applications in the silk industry. © 2014 Society of Chemical Industry.

  15. Effect of spent bleaching earth based bio organic fertilizer on growth, yield and quality of eggplants under field condition

    Science.gov (United States)

    Cheong, K. Y.; Loh, S. K.; Salimon, J.

    2013-11-01

    Spent bleaching earth (SBE) is a solid waste generated from the bleaching process in palm oil industry. This solid waste is currently disposed directly in landfills without treatment, causing severe water and air pollution. Recently, dumping of SBE in landfills or public disposal sites has been prohibited in most countries. Meanwhile, high costs associated with the large area of land needed for storage of the residue has lead to the interest in regenerate SBE. Thus, a recent novel approach has been carried out on the utilization of SBE in agriculture as an alternative method for disposal. In this study, a field experiment was conducted at an experimental plot in Plant House National University Malaysia to evaluate the effect of SBE on the growth and quality of eggplant. Growth and quality parameters of eggplant including total fruit yield, total biomass, macronutrients concentration of leaf were studied through close monitoring and assessment. Field trials conducted showed that SBE is effective in promoting eggplant growth and nutrient uptake compared to the control treatment under field conditions. Therefore, with the proper and effective ways in handling SBE through conversion of SBE into beneficial bio organic fertilizer, this material which is a waste in the past will become an advantage in agriculture as a substitute for commercial fertilizers.

  16. Process design of in situ esterification-transesterifica tion for biodiesel production from residual oil of spent bleaching earth (SBE)

    Science.gov (United States)

    Suryani, A.; Mubarok, Z.; Suprihatin; Romli, M.; Yunira, E. N.

    2017-05-01

    Indonesia is the largest producer of Crude Palm Oil (CPO) in the world. CPO refining process produces spent bleaching earth (SBE), which still contains 20-30% oil. This residual oil is very potential to be developed as a biodiesel feedstock. The purpose of this research was to develop an in situbiodiesel production process of residual oil of SBE, which covered stirring speed of esterification and transesterification and also transesterification time to produce biodiesel with the best characteristics. The production was conducted in a 100 L reactor. The stirring speeds applied were 650 rpm and 730 rpm, and the transesterification time varied at 60, 90 and 120 minutes. The combination of 730 rpm stirring speed for 90 minutes transesterification resulted in the best biodiesel characteristics with the yield of 85%, the specific energy of 6,738 kJ/kg and the heater efficiency of 48%. The physico-chemical properties of biodiesel was in conformity with the SNI of Biodiesel.

  17. Evidence-based assessment of the efficacy and effectiveness of light/laser activation in in-office dental bleaching

    Directory of Open Access Journals (Sweden)

    Reem A Ajaj

    2012-01-01

    Full Text Available Many in-office bleaching techniques use the light/laser in conjunction with the bleaching agent claiming more favorable bleaching results. Controversy still exists in the literature as to the role of a light/laser in bleaching results. The goal of this study is to determine, through Comparative Effectiveness-Efficacy Research and Analysis for Practice (CEERAP, if the co-use of light/laser activation with the chemical bleaching agent has improved teeth whitening compared to using the chemical bleaching agent alone. Systematic reviews and randomized clinical trials on the research question were obtained using multiple search engines. Assessment of the level and quality of evidence and acceptable sample analysis were performed for the Randomized Clinical Trials (RCTs. Due to heterogeneity of the acceptable studies, meta-analysis was performed only on the two most homogenous studies. Qualitative assessment of the acceptable studies was performed. The strength of clinical recommendation was assessed. Only one qualitative systematic review was found. Eight articles were accepted as high quality RCTs. The meta-analysis shows preferable outcome when using the light activation with the bleaching material than when using the bleaching material alone. Qualitative assessment of the acceptable studies shows conflicting results. Most studies agreed that the use of light is proven to increase the whitening effect of the bleaching agent, especially for a short term after treatment. Additional studies with greater consistency in methodology and outcomes are needed to be able to reach a definite consensus regarding the effectiveness of using light during bleaching through an overarching meta-analysis for more powerful statistical results.

  18. Effects of different activation processes on H2O2/TAED bleaching of Populus nigra chemi-thermo mechanical pulp

    OpenAIRE

    Qiang Zhao; Dezhi Sun; Zhaohong Wang; Junwen Pu; Xiaojuan Jin; Mian Xing

    2012-01-01

    Tetra acetyl ethylene diamine (TAED) was used as an activator in H2O2 bleaching to improve bleaching efficiency. The present work was aimed at confirming different activations for various H2O2/TAED bleaching processes, including the addition of acetic anhydride and the step-addition of sodium hydroxide. The results showed that an acetic anhydride dosage of 1%, an acetic anhydride treatment time of 10 min, and an addition time of 45 min were the optimal treatment conditions. The optimum proces...

  19. Adsorption studies on bleaching of palm-kernel oil with activated ...

    African Journals Online (AJOL)

    Adsorption studies were performed on bleaching of palm-kernel oil (PKO) with different weight ratios of activated bentonite clay/PKO, ranging from 0.25% to 3% and at different temperatures of 70ºC, 80ºC, 90ºC and 100ºC. The equilibrium data generated were subsequently fitted with Langmuir and Freundlich adsorption ...

  20. Effects of bleach activator, sodium alkyl acyloxybenzene sulfonate, on house dust mites (Dermatophagoides farinae).

    Science.gov (United States)

    Tobe, Seiichi; Kamezaki, Hiroki; Watanabe, Toshiyuki; Takaoka, Hiromitsu; Sakaguchi, Masahiro

    2010-01-01

    House dust mites (Dermatophagoides farinae) in bedding and clothes are a major allergen. However, house dust mites cannot be killed by general washing conditions under 50 degrees C. Therefore, low-temperature washing conditions must be improved to eliminate house dust mites. Sodium alkyl acyloxybenzene sulfonate (OBS) is a bleach activator that is used to intensify the bleaching effects of some laundry products. The purpose of this study was to evaluate the effect of OBS on the elimination of house dust mites in low-temperature washing conditions. D. farinae was soaked in solutions containing different types of OBS for various durations and at various temperatures. The miticidal effects of the various washing conditions were also evaluated for D. farinae. Then sodium lauroyloxybenzene sulfonate (OBS-12) produced the highest D. farinae mortality rate among the OBS solutions that were examined and had a stronger miticidal effect than available chlorine under general washing conditions. OBS exhibited miticidal effects under general washing conditions at low temperatures. Since OBS is already used as an additive in some laundry products to increase the bleaching activity, OBS can be easily used to kill house dust mites under general washing conditions.

  1. Studi Pemanfaatan Limbah Padat Industri Pengolahan Minyak Kelapa Sawit Spent Bleaching Earth sebagai Pengganti Agregat pada Campuran Beton

    Directory of Open Access Journals (Sweden)

    Denny Dermawan

    2018-03-01

    Full Text Available Palm oil refinery factory has solid waste by product  called Spent Bleaching Earth (SBE. SBE consists of some chemical compounds and one of them  is SiO2 up to 83,05%. SiO2 or silica fume can cause silicosis if it is exposed to the atmosphere and frequently inhaled by the workers.  On the other hand,  SiO2  is one of the material  composition of Portland cement. Thus, it is necessary to conduct a research about the utilization of SBE. as a concrete mixture. SBE is utilized as fine aggregate substitution by the composition of 0%, 10%, 20%, 30%, and 40% of the total amount of fine aggregate. The conducted tests are fineness modulus calculation, compressive strength, setting time, and TCLP. The method used for mix  design is SNI 03-2834-2000 with f’c 28,5 MPa and slump 12 ± 2 cm. This research  shows  that concretes with SBE substitution which achieve the planned compressive strength are 10% SBE with 34,16 MPa and 20% SBE with 29,06 MPa. Based on the TCLP test, the concentration of heavy metal substances in 10% SBE are below the standard. Thus, it is  scientifically proven to conclude that concrete with 10% SBE is technically proper and safe for the environment.

  2. Exogenous bleaching evaluation on dentin using chemical activated technique compared with diode laser technique

    International Nuclear Information System (INIS)

    Carvalho, Breno Carnevalli Franco de

    2003-01-01

    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 μm (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)

  3. 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 < 0.05). The data in this vitro explorative study suggest the activation of hydrogen peroxide by different sources may further affect the shear bond strength of subsequent 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.

  4. New Insights on Degumming and Bleaching Process Parameters on The Formation of 3-Monochloropropane-1,2-Diol Esters and Glycidyl Esters in Refined, Bleached, Deodorized Palm Oil.

    Science.gov (United States)

    Sim, Biow Ing; Muhamad, Halimah; Lai, Oi Ming; Abas, Faridah; Yeoh, Chee Beng; Nehdi, Imededdine Arbi; Khor, Yih Phing; Tan, Chin Ping

    2018-04-01

    This paper examines the interactions of degumming and bleaching processes as well as their influences on the formation of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters in refined, bleached and deodorized palm oil by using D-optimal design. Water degumming effectively reduced the 3-MCPDE content up to 50%. Acid activated bleaching earth had a greater effect on 3-MCPDE reduction compared to natural bleaching earth and acid activated bleaching earth with neutral pH, indicating that performance and adsorption capacities of bleaching earth are the predominant factors in the removal of esters, rather than its acidity profile. The combination of high dosage phosphoric acid during degumming with the use of acid activated bleaching earth eliminated almost all glycidyl esters during refining. Besides, the effects of crude palm oil quality was assessed and it was found that the quality of crude palm oil determines the level of formation of 3-MCPDE and glycidyl esters in palm oil during the high temperature deodorization step of physical refining process. Poor quality crude palm oil has strong impact towards 3-MCPDE and glycidyl esters formation due to the intrinsic components present within. The findings are useful to palm oil refining industry in choosing raw materials as an input during the refining process.

  5. Bleaching efficacy of whitening agents activated by xenon lamp and 960-nm diode radiation.

    Science.gov (United States)

    Wetter, Niklaus Ursus; Walverde, Déboraayala; Kato, Ilka Tiemy; Eduardo, Carlos de Paula

    2004-12-01

    This in vitro study examines the efficacy of two different dental whitening agents, Opalescence Xtra and Opus White, by analyzing the change in color achieved by the treatment and the temperature increase induced in the pulpal chamber. Bleaching techniques achieved significant advances with the use of coherent or incoherent radiation sources to activate the bleaching chemicals. The bleaching agents, containing 35% of hydrogen peroxide, were stimulated with 0.9 W of xenon arc lamp and 0.9 W or 2 W of a 960-nm diode laser during 60 sec (0.9 W) and 30 sec (2 W) on 33 extracted human teeth. During irradiation, the temperature in the pulpal cavity was monitored. The color change was evaluated using the CIE L*a*b* color space measurement system. The treated groups showed an increase in color saturation (DeltaC*) of 3-32% and a change in whiteness (DeltaL*) of 0-8%. This study found that only some of the irradiated groups show statistically significant difference (p effectiveness of their treatment when compared to the control, whereas no significant statistical difference was obtained in between the irradiated groups. Temperature increase was 2-4 degrees C when using the xenon arc lamp, 2-8 degrees C and 4-12 degrees C when using the diode laser at 0.9 W and 2 W, respectively. The results of this study suggest that Opalescence Extra and Opus White are both effective to provide brighter teeth. However, according to the conditions used in this study, only the xenon arc lamp induced a safer temperature increase.

  6. Bioremediation of Spent Bleaching Earth (SBE Wastes using Lipolitic Bacteria (Bacillus cereus with Variation of Inoculum Volume

    Directory of Open Access Journals (Sweden)

    Maria Lusia

    2018-01-01

    Full Text Available Spent bleaching earth (SBE is a solid waste was generated from the CPO refining step into cooking oil.  SBE that was discharged directly into the environment has the potential to pollute the environment, because in the SBE waste contained oil and acid residues, which are easily to be oxidized and flammable.  Therefore, SBE must be processed first before being discharged into the environment.  One way to manage SBE is by bioremediation.  Bioremediation is a method on cleaning the environment from contaminants by using  biological agents, such as bacteria, fungi etc.  The bacterial isolates used in this study were Bacillus cereus.  This study aims to obtain the best inoculum and to know the ability of Bacillus cereus bacteria in degrading the oil content in SBE waste. This study used Completely Randomized Design with the volume of Bacillus cereus bacteria inoculum as a treatment, consisting of 6 treatment levels of 0 mL kg-1, 25 mL kg-1, 50 mL kg-1, 75 mL kg-1, 100 mL kg-1, 125 mL kg-1.  Each treatment level was repeated 3 times, so taht 18 experimental units were obtained.  Observation was done once a week, in a month.  Parameters observed were bacterial population, percentage of oil degradation, and oil content degradation.  The best treatment result for the bacterial population was obtained at the treatment of 100 mL kg-1, at week 4 which was 7,4 x 108 cfu g-1, and for the oil degradation was obtained at 50 mL kg-1 on the treatment at week 4 as big as 90,43%.

  7. Effects of light activation, agent concentration, and tooth thickness on dental sensitivity after bleaching.

    Science.gov (United States)

    Moncada, G; Sepúlveda, D; Elphick, K; Contente, M; Estay, J; Bahamondes, V; Fernandez, E; Oliveira, O B; Martin, J

    2013-01-01

    Examining three bleaching systems, this in vivo clinical trial evaluated the relationship among tooth sensitivity, light activation, and agent concentration, and it correlated dental sensitivity with tooth thickness. Eighty-seven volunteer patients were included. Inclusion criteria were the presence of anterior teeth without restorations as well as the absence of a previous bleaching experience and absence of noncarious cervical lesions or dental pain. Exclusion criteria included pregnancy or breastfeeding, a maximum of TF3 hypoplasia, tetracycline-fluorosis stains, malpositioned teeth, orthodontic treatment, periodontal disease, and/or analgesic/anti-inflammatory intake. Patients were randomly assigned to three bleaching groups: Group A (n=25) was treated with 15% H2O2 and nitrogenous-titanium-dioxide and was light activated (Lase Peroxide Lite, DMC, SaoCarlos, Sao Paulo, Brazil); Group B (n=27) was treated with 35% H2O2 and was light activated (Lase Peroxide Sensy, DMC); and Group C (n=35) was treated with 35% H2O2 (White Gold Office, Dentsply, 38West Clark Ave., Milford, USA) without light activation. Tooth sensitivity (TS) was self-reported by the patients using the visual analog scale (VAS) at baseline (TS0), immediately after treatment (TSI), and at seven days after treatment (TS7). In 46 patients, tooth thickness was determined by computed tomography. TS0, TSI, and TS7 were compared between the A and B groups to determine the effect of concentration and between the B and C groups to determine the effect of light using analysis of covariance. The correlation between tooth thickness and TSI was determined by Spearman Rho test (SPSS 15). Eighty-seven patients were evaluated at baseline, and 61 were evaluated at seven days. Separated by groups, tooth sensitivity, expressed as VAS value at the time points TS0, TSI, and TS7, respectively, were as follows: Group A: 13.76 ± 13.53, 24.40 ± 25.24, and 5.94 ± 5.5; Group B: 15.07 ± 18.14, 42.4 ± 31.78, and 8.68

  8. Vital tooth bleaching with Nightguard vital bleaching.

    Science.gov (United States)

    Haywood, V B; Robinson, F G

    1997-01-01

    Between July 1994 and May 1996, several landmark articles were published concerning the safety and efficacy of vital tooth bleaching with 10% carbamide peroxide in a customfitted tray. The American Dental Association (ADA) published guidelines for ADA acceptance, and three products received approval. Long-term clinical trials on 38 patients indicated 92% successful bleaching after 6 weeks of treatment. Results were stable in 74% of the patients at 1.5 years, and in 62% of the patients at 3-year follow-up with no further treatment. Clinical pulpal studies and periodontal studies indicated no detrimental safety problems, although some laboratory cell studies suggested concerns. The noncarcinogenic potential of 10% carbamide peroxide was established in animal studies. Successful bleaching of tetracycline-stained teeth was achieved after 6 months of treatment, with no tooth problems detected clinically or by scanning electron micrograph. Extended treatment times are effective on other stains from dentinogenesis imperfecta or nicotine. On insertion in the mouth, 10% carbamide peroxide elevated the pH in the tray and saliva. After 4 hours of clinical wear, over 60% of the newer, thicker materials (Opalescence [Ultraclent Products, South Jordon, UT] and Platinum [Colgate Oral Pharmaceuticals, Canton, MA]) was present and active in the tray. Nightguard vital bleaching seems to be the most cost-efficient, user-friendly, patient-accepted method of bleaching teeth available to the profession and is safe and effective. Over-the-counter products can have harmful effects on tooth structure and may not lighten teeth.

  9. Peroxy bleaches

    International Nuclear Information System (INIS)

    Carson, P.A.; Fairclough, C.S.; Mauduit, C.; Colsell, M.

    2006-01-01

    Fabric laundering is now a sophisticated chemical process involving a variety of operations including bleaching. The chemistry of peroxy bleaches is described including the use of novel organic compounds to provide effective bleaching at the lower temperatures of modern wash cycles. The instability of peroxy compounds is illustrated using cameo case histories to relate theory and practice. Techniques available for determining their thermochemistry are summarised. A model is provided for hazard and risk assessment of development projects in general (particularly those involving new molecules, processes or formulations) from ideas phase through exploratory laboratory investigations to pilot plant scale-up and eventual manufacture and commercial exploitation. This paper is a prelude to Part 2, which describes the determination of thermodynamic and kinetic properties of peroxy bleaches and discusses the implication of the results in terms of precautions for their safe storage and incorporation into detergent formulations during processing

  10. In vitro assessment of chemical activation efficiency during in-office dental bleaching.

    Science.gov (United States)

    Travassos, Alessandro Caldas; Rocha Gomes Torres, Carlos; Borges, Alessandra Buhler; Barcellos, Daphne Câmara

    2010-01-01

    This study compared five types of chemical catalyzing agents added to 35% hydrogen peroxide gel, with regard to their capacity of intensifying in-office dental bleaching results. One-hundred and twenty bovine incisors were used, of which the crowns and roots were cut in the incisor-apical direction, to acquire the dimensions of a human central incisor. The specimens were sectioned in the mesiodistal direction by means of two longitudinal cuts, the lingual halves being discarded. The vestibular halves received prophylaxis with a bicarbonate jet, ultrasound cleaning and acid etching on the dentinal portion. Next, the specimens were stored in receptacles containing a 25% instant coffee solution for two weeks. After the darkening period, initial measurement of the shade obtained was taken with the Easy Shade appliance, which allowed it to be quantified by the CIELab method. The samples were divided into six groups, corresponding to the chemical activator used: a) none (CON); b) ferric chloride (CF); c) ferrous sulphate (SF); d) manganese gluconate (GM); e) manganese chloride (CM); f) mulberry root extract (RA). Each group received three 10-minute applications of the gels containing the respective activating agents. Next, a new shade measurement was made. The Analysis of Variance and Tukey tests (alpha = 5%) showed statistically significant differences for the shade perception values (p = 0.002). Groups GM, CM and RA showed significantly higher means than the control group. The presence of some chemical activators is capable of resulting in a significant increase in tooth shade variation.

  11. 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.

  12. EarthScope Content Module for IRIS Active Earth Monitor

    Science.gov (United States)

    McQuillan, P. J.; Welti, R.; Johnson, J. A.; Shiffman, C. R.; Olds, S. E.

    2012-12-01

    The Active Earth Monitor (AEM) is an interactive computer-based display for university lobbies, museums, visitor centers, schools and libraries. AEM runs in a standard Internet web browser in full screen mode. The display consists of a customizable set of content pages about plate tectonics, earthquakes, volcanoes and tsunamis. Low-cost and simple-to-implement, the Active Earth Monitor provides a way to engage audiences with earth science information without spending resources on a large exhibit. The EarthScope Active Earth Monitor content set highlights the connections between the landscape and the research and monitoring being conducted by EarthScope in partnership with regional monitoring networks. Modules consist of chapters that focus on What is EarthScope?, EarthScope Observatories, and EarthScope Research Results. Content topics are easily explored using a web page button type navigation interface via a touch screen or mouse. A formative evaluation of general public users informed the interface design. Chapters in the modules start with a general overview and proceed to detailed specifics. Each chapter utilizes at least one set of live or near real-time research data (often more than one). This exposes the general public to active ongoing research that is engaging, relevant to the individual user, and explained in easy to understand terms. All live content is updated each time a user accesses the individual page displaying the live data. Leading questions are presented allowing the user to examine the content before accessing the answer via pop-up box. Diagrams and charts of research data have explanatory keys that allow users to self explore all content. Content pages can be created and inserted in the Active Earth Monitor by utilizing the simple HTML/CSS coding.;

  13. 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 %.

  14. Optimization of Bleaching Parameters for Soybean Oil

    Directory of Open Access Journals (Sweden)

    Tomislav Domijan

    2012-01-01

    Full Text Available The final stage of edible soybean oil manufacture is refining, the most delicate phase of which is bleaching. At this step, undesirable substances are removed, such as pigments, traces of metals, phospholipids and certain degradation products. However, certain valuable compounds such as tocopherols and sterols may also be removed, significant loss of oxidative stability can occur, and fatty acid content may increase. To avoid these negative oil changes, bleaching parameters such as the concentration of bleaching clay, temperature and duration should be optimized. Since bleaching conditions depend on the properties of the bleaching clay as well as on the type of crude oil, bleaching parameters should be optimized with different types of clay for each vegetable oil. Since such optimization has not yet been reported for soybean oil treated with Pure-Flo® Supreme Pro-Active bleaching adsorbent, this study investigates the effect of bleaching parameters on bleaching efficiency, oxidative stability and the content and composition of bioactive compounds (tocopherols and sterols using the above mentioned clay in this type of oil. Results show that the amount of clay had the greatest influence on bleaching efficiency, especially according to the Lovibond scale, on transparency, and on phosphorus content. Temperature and clay amount significantly affected oxidative stability, in particular the formation of secondary oxidation products. Increasing the amount of clay decreased tocopherol content of the bleached oil. Neutralized soybean oil bleached for 20 min at 95 °C with 1 % Pure-Flo® Supreme Pro-Active bleaching clay showed the highest oxidative stability, best bleaching efficiency, and most favourable sterol content, although tocopherol content was reduced.

  15. Paleoseismology: evidence of earth activity

    Czech Academy of Sciences Publication Activity Database

    Nováková, Lucie

    2016-01-01

    Roč. 105, č. 5 (2016), 1467-1469 ISSN 1437-3254 Institutional support: RVO:67985891 Keywords : Paleoseismology * Colluvial wedge * White Creek Fault _ * Greendale Fault * San Andreas Fault * Paganica Fault Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.283, year: 2016

  16. Lignin Peroxidase Activity Is Not Important in Biological Bleaching and Delignification of Unbleached Kraft Pulp by Trametes versicolor

    Science.gov (United States)

    Archibald, Frederick S.

    1992-01-01

    The discovery in 1983 of fungal lignin peroxidases able to catalyze the oxidation of nonphenolic aromatic lignin model compounds and release some CO2 from lignin has been seen as a major advance in understanding how fungi degrade lignin. Recently, the fungus Trametes versicolor was shown to be capable of substantial decolorization and delignification of unbleached industrial kraft pulps over 2 to 5 days. The role, if any, of lignin peroxidase in this biobleaching was therefore examined. Several different assays indicated that T. versicolor can produce and secrete peroxidase proteins, but only under certain culture conditions. However, work employing a new lignin peroxidase inhibitor (metavanadate ions) and a new lignin peroxidase assay using the dye azure B indicated that secreted lignin peroxidases do not play a role in the T. versicolor pulp-bleaching system. Oxidative activity capable of degrading 2-keto-4-methiolbutyric acid (KMB) appeared unique to ligninolytic fungi and always accompanied pulp biobleaching. PMID:16348775

  17. Comparison of laser and power bleaching techniques in tooth color change

    OpenAIRE

    Fekrazad, Reza; Alimazandarani, Shervin; Kalhori, Katayoun A.M.; Assadian, Hadi; Mirmohammadi, Seyed-Mahdi

    2017-01-01

    Background Laser-assisted bleaching uses laser beam to accelerate release of free radicals within the bleaching gel to decrease time of whitening procedure. The aim of this study was to compare the efficacy of power bleaching using Opalescence Xtra Boost? and laser bleaching technique using LaserSmile gel and diode laser as an activator in their tooth whitening capacity. Material and Methods Student t test showed that the laser bleaching group significantly outperformed the power bleaching gr...

  18. An effective ostrich oil bleaching technique using peroxide value as an indicator.

    Science.gov (United States)

    Palanisamy, Uma Devi; Sivanathan, Muniswaran; Radhakrishnan, Ammu Kutty; Haleagrahara, Nagaraja; Subramaniam, Thavamanithevi; Chiew, Gan Seng

    2011-07-05

    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.

  19. 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.

  20. NASA'S Earth Science Data Stewardship Activities

    Science.gov (United States)

    Lowe, Dawn R.; Murphy, Kevin J.; Ramapriyan, Hampapuram

    2015-01-01

    NASA has been collecting Earth observation data for over 50 years using instruments on board satellites, aircraft and ground-based systems. With the inception of the Earth Observing System (EOS) Program in 1990, NASA established the Earth Science Data and Information System (ESDIS) Project and initiated development of the Earth Observing System Data and Information System (EOSDIS). A set of Distributed Active Archive Centers (DAACs) was established at locations based on science discipline expertise. Today, EOSDIS consists of 12 DAACs and 12 Science Investigator-led Processing Systems (SIPS), processing data from the EOS missions, as well as the Suomi National Polar Orbiting Partnership mission, and other satellite and airborne missions. The DAACs archive and distribute the vast majority of data from NASA’s Earth science missions, with data holdings exceeding 12 petabytes The data held by EOSDIS are available to all users consistent with NASA’s free and open data policy, which has been in effect since 1990. The EOSDIS archives consist of raw instrument data counts (level 0 data), as well as higher level standard products (e.g., geophysical parameters, products mapped to standard spatio-temporal grids, results of Earth system models using multi-instrument observations, and long time series of Earth System Data Records resulting from multiple satellite observations of a given type of phenomenon). EOSDIS data stewardship responsibilities include ensuring that the data and information content are reliable, of high quality, easily accessible, and usable for as long as they are considered to be of value.

  1. Effects of black liquor shocks on activated sludge treatment of bleached kraft pulp mill wastewater.

    Science.gov (United States)

    Morales, Gabriela; Pesante, Silvana; Vidal, Gladys

    2015-01-01

    Kraft pulp mills use activated sludge systems to remove organic matter from effluents. Process streams may appear as toxic spills in treatment plant effluents, such as black liquor, which is toxic to microorganisms of the activated sludge. The present study evaluates the effects of black liquor shocks in activated sludge systems. Four black liquor shocks from 883 to 3,225 mg chemical oxygen demand-COD L(-1) were applied during 24 hours in a continuously operating lab-scale activated sludge system. Removal efficiencies of COD, color and specific compounds were determined. Moreover, specific oxygen uptake rate (SOUR), sludge volumetric index (SVI) and indicator microorganisms were evaluated. Results show that the addition of black liquor caused an increase in COD removal (76-67%) immediately post shock; followed two days later by a decrease (-19-50%). On the other hand, SOUR ranged between 0.152 and 0.336 mgO2 g(-1) volatile suspended solids-VSS• min(-1) during shocks, but the initial value was reestablished at hour 24. When the COD concentration of the shock was higher than 1,014 mg/L, the abundance of stalked ciliates and rotifers dropped. Finally, no changes in SVI were observed, with values remaining in the range 65.8-40.2 mL g(-1) total suspended solids-TSS during the entire operating process. Based on the results, the principal conclusion is that the activated sludge system with the biomass adapted to the kraft pulp effluent could resist a black liquor shock with 3,225 mgCOD L(-1) of concentration during 24 h, under this study's conditions.

  2. Edible Earth and Space Science Activities

    Science.gov (United States)

    Lubowich, D.; Shupla, C.

    2014-07-01

    In this workshop we describe using Earth and Space Science demonstrations with edible ingredients to increase student interest. We show how to use chocolate, candy, cookies, popcorn, bagels, pastries, Pringles, marshmallows, whipped cream, and Starburst candy for activities such as: plate tectonics, the interior structure of the Earth and Mars, radioactivity/radioactive dating of rocks and stars, formation of the planets, lunar phases, convection, comets, black holes, curvature of space, dark energy, and the expansion of the Universe. In addition to creating an experience that will help students remember specific concepts, edible activities can be used as a formative assessment, providing students with the opportunity to create something that demonstrates their understanding of the model. The students often eat the demonstrations. These demonstrations are an effective teaching tool for all ages, and can be adapted for cultural, culinary, and ethnic differences among the students.

  3. ADSORPTION ON HEAT REGENERATED SPENT BLEACHING ...

    African Journals Online (AJOL)

    Preferred Customer

    KINETICS AND THERMODYNAMICS OF AQUEOUS Cu(II) ADSORPTION ON. HEAT REGENERATED SPENT BLEACHING EARTH. Enos W. Wambu1*, Gerald K. Muthakia2*, Joseph K. wa-Thiong'o1 and Paul M. Shiundu3. 1Department of Chemistry, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya.

  4. Endogenic Activity of the Earth and Moon

    Science.gov (United States)

    Marakushev, A. A.

    1998-01-01

    The endogenic activity of the Earth and Moon is created by the H fluid flows that ascends from their liquid cores and generates magnetic fields. In these flows, the generation of water together with hydrocarbons (3H2+CO = CH4+H2O), carbon (H2+CO=C+H2O), carbon dioxide (H2+3CO=C+CO2+H2O) and nitrogen (2H2+2NO=N2+2H2O) occurs. Water in fluids strongly lowers the melting temperature of rocks and thereby initiates magmatic activity and, making it to the surface, aids the generation of Earth's hydrosphere and aqueous ice covers of satellites. The endogenic activity of a planet or satellite stops after its complete consolidation; this occurs simultaneously with the disappearing of the magnetic field. Endogenic activity of the Earth continued for about 4.6 m.y. because of the existence of a liquid core rich with H. The other planets of the Earth's group lost their endogenic activity as well as magnetic fields due to complete consolidation. The Moon is the oldest known of the solar system bodies. Volcanic activity occurred on the Moon at 4.6-3.2 GA when it had a strong magnetic field, which is thought to be responsible for residual magnetization inherent in the samples. By analogy to the Moon, whose activity has been suppl.ied by its fluid reservoir for about 1.5 m .y., the current volcanic activity on Jupiter's satellite Io, (analogous to the Moon) suggest that Jupiter's satellite system is relatively young. This is confirmed by discoveries of the magnetic fields of Io, Europa, and Ganymede. However, Callisto is completely consolidated and has lots its magnetic field. The endogenic activity resulted in explosive volcanism on Io, and in the formation of aqueous ice covers on Europa and Ganymede. The ice cover of Europa si still forming, judging from the lack of meteoritic craters on its surface.

  5. 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 ...

  6. The combination of activated natural zeolite-bentonite to reduce Fe and Cu in refined bleached palm oil (RBPO) by using atomic absorption spectrophotometer method

    Science.gov (United States)

    Zakwan; Raja, PM; Giyanto

    2018-02-01

    Indonesia is one of the crude palm oil (CPO) production country in the world. As many products are derivated from the CPO, the quality must be increased continuously. One of the things that influence the quality of palm oil is the Fe and Cu content. The objective of this research was to reduce Fe and Cu content in Refined Bleached Palm Oil (RBPO). In processing CPO or Refined Bleachead Palm Oil (RBPO) may be contaminated by Fe and Cu from metal tank and pipe in the factory. The zeolite and bentonite was activated by maceration method using hydrochloric acid (0,1 N). Four batch reactions consisting of refined palm oil (RPO), activated natural zeolite-bentonite (ANZB) was bleached by heating and stirring them at about 105°C and 1200 rpm for 30 minutes. The results showed that all combinations of ANZB can reduce the Fe content. Thereafter, the optimal combination of ANZB was obtained in K1, K2 and K4 with Cu content 0.02 ppm. In the future, it is needed to study on the reduction of the Fe and Cu content in palm oil with the other adsorbent.

  7. Natural Zeolite Sample and Investigation Its Use in Oil Bleaching Sector

    Science.gov (United States)

    Bilgin, Oyku

    2017-12-01

    In the sector of oil bleaching, the stored raw oil is subjected to physical and chemical methods such as degumming, neutralization, bleaching, deodorization and winterization. In the process of oil bleaching, the selection of correct bleaching earth in accordance with oil characteristics matters so much. Bleaching earth is an inorganic product used in removing impurities being available within the structures of vegetable, animal oil (sunflower, soya, corn, palm, tallow, rapeseed, fish oils…etc.) and fatty acids, mineral oils (glycerine, paraffin, mineral motor oils. etc.) with the adsorption process. The factors such as low cost of oil bleaching earth, low ratio of oil retaining, high bleaching capacity in spite of using them in small amounts, filter’s delayed blocking by the earth and non-increase of the free acidity of the oil should be taken into consideration. Bleaching earths are processed with some acids in order to widen their surface areas. During this process, a certain amount of acid is left within oil bleaching earths even if it is very little. These acids also increase oil’s acidity by oxidizing oil in the course of bleaching process. In this study, zeolite sample taken from Manisa -Demirci region was used. Following the processes of crushing and sieving, zeolite sample was subjected to chemical analyses according to their grain thickness, microscopic examination, the analyses of XRD and cation exchange capacity and their ore characteristics were determined. Afterwards, it was searched whether zeolite sample has oil bleaching ability or not or whether it can be used as oil bleaching earth or not.

  8. Therapeutic effectiveness of a new enzymatic bleaching dentifrice.

    Science.gov (United States)

    Forner, Leopaldo; Amengual, José; Liena, Carmen; Riutord, Pere

    2012-01-01

    Research into bleaching focuses on new products in order to minimize undesirable effects. This study evaluated the bleaching effectiveness of a new enzymatic-activated dentifrice. A total of 20 volunteers were bleached with a dentifrice containing 5% lactoperoxidase and 3% carbamide peroxide applied three times a day for two minutes over 21 days. Color was recorded before and after the treatment using a spectrophotometer. CIELAB differences were calculated before and after treatment using the paired t test (P whitening teeth. Enzymatic dental bleaching is able to increase the efficiency of low concentration peroxides, reducing the potential risk of peroxides on oral tissues.

  9. Alternative bleaching methods for Cheddar cheese whey.

    Science.gov (United States)

    Kang, E J; Smith, T J; Drake, M A

    2012-07-01

    Residual annatto colorant (norbixin) in fluid Cheddar cheese whey can be bleached. The 2 approved chemical bleaching agents for whey, hydrogen peroxide (HP) and benzoyl peroxide (BP), negatively impact the flavor of dried whey protein. The objective of this study was to evaluate alternative methods for bleaching liquid whey: ultraviolet radiation (UV), acid-activated bentonite (BT), and ozone (OZ). Colored Cheddar cheese whey was manufactured followed by pasteurization and fat separation. Liquid whey was subjected to one of 5 treatments: control (CT) (no bleaching; 50 °C, 1 h), HP (250 mg/kg; 50 °C, 1 h), UV (1 min exposure; 50 °C), BT (0.5% w/w; 50 °C, 1 h), or OZ (2.2g/h, 50 °C, 1 h). The treated whey was then ultrafiltered, diafiltered, and spray-dried to 80% whey protein concentrate (WPC80). The entire experiment was replicated 3 times. Color (norbixin extraction and measurement), descriptive sensory, and instrumental volatile analyses were conducted on WPC80. Norbixin elimination was 28%, 79%, 39%, and 15% for HP, BT, UV, and OZ treatments, respectively. WPC80 from bleached whey, regardless of bleaching agent, had lower sweet aromatic and cooked/milky flavors compared to unbleached CT (P < 0.05). The HP and BT WPC80 had higher fatty flavor compared to the CT WPC80 (P < 0.05), and the UV and OZ WPC80 had distinct mushroom/burnt and animal flavors. Volatile compound results were consistent with sensory results and confirmed higher relative abundances of volatile aldehydes in UV, HP, and OZ WPC80 compared to CT and BT WPC80. Based on bleaching efficacy and flavor, BT may be an alternative to chemical bleaching of fluid whey. The 2 approved chemical bleaching agents for whey, hydrogen peroxide (HP) and benzoyl peroxide (BP), negatively impact flavor of dried whey protein, and restrictions on these agents are increasing. This study evaluated 3 alternatives to chemical bleaching of fluid whey: UV radiation, ozone, and bentonite. © 2012 Institute of Food

  10. Statistical analysis on activation and photo-bleaching of step-wise multi-photon activation fluorescence of melanin

    Science.gov (United States)

    Gu, Zetong; Lai, Zhenhua; Zhang, Xi; Yin, Jihao; DiMarzio, Charles A.

    2015-03-01

    Melanin is regarded as the most enigmatic pigments/biopolymers found in most organisms. We have shown previously that melanin goes through a step-wise multi-photon absorption process after the fluorescence has been activated with high laser intensity. No melanin step-wise multi-photon activation fluorescence (SMPAF) can be obtained without the activation process. The step-wise multi-photon activation fluorescence has been observed to require less laser power than what would be expected from a non-linear optical process. In this paper, we examined the power dependence of the activation process of melanin SMPAF at 830nm and 920nm wavelengths. We have conducted research using varying the laser power to activate the melanin in a point-scanning mode for multi-photon microscopy. We recorded the fluorescence signals and position. A sequence of experiments indicates the relationship of activation to power, energy and time so that we can optimize the power level. Also we explored regional analysis of melanin to study the spatial relationship in SMPAF and define three types of regions which exhibit differences in the activation process.

  11. Coral Bleaching Assessment Through Remote Sensing and Integrated Citizen Science (CoralBASICS): Engaging Dive Instructors on Reef Characterization in Southwest, Puerto Rico Coupled with the Analysis of Water Quality Using NASA Earth Observations

    Science.gov (United States)

    Torres-Perez, J. L.; Armstrong, R.; Detres, Y.; Aragones-Fred, C.; Melendez, J.

    2017-12-01

    As recurrences of extreme sea water thermal events increase with climate change, the need for continuous monitoring of coral reefs becomes even more evident. Enabling properly trained members from the local communities to actively participate in scientific programs/research projects, provides for such monitoring at little cost once the citizens are properly trained and committed. Further, the possibility of obtaining high temporal resolution data with citizen scientists can provide for new venues to answer questions that may not be answered with traditional research approaches. The CoralBASICS project engages members of the local diving industry in Puerto Rico on the assessment of coastal water quality and the status of Puerto Rico's coral reefs in an age of climate change and in particular, an increase in the frequency and magnitude of coral bleaching events. The project complements remote sensing data with community-based field assessments strictly supervised by the PI's. The study focuses on training citizen scientists (dive instructors) on the collection of benthic information related to the state of coral reefs using the Reef Check (fish and invertebrates ID and substrate composition) and video transects methodologies, monitoring of coral bleaching events, and collecting of water quality data using a smartphone ocean color application. The data collected by citizen scientists complements the validation of Landsat-8 (OLI) imagery for water quality assessment. At the same time, researchers from the University of Puerto Rico conduct field assessment of the bio-optical properties of waters surrounding the coral reef study areas. Dive instructors have been collecting benthic and water quality data for the past 4 months. Initial analysis using the Coral Point Count with excel extension (CPCe) software showed a dominance of gorgonians at most sites (up to 32.8%) with hard coral cover ranging between 5.5-13.2% of the hard substrates. No coral diseases or bleaching

  12. Dynamic active earth pressure on retaining structures

    Indian Academy of Sciences (India)

    Abstract. Earth-retaining structures constitute an important topic of research in civil engineering, more so under earthquake conditions. For the analysis and design of retaining walls in earthquake-prone zones, accurate estimation of dynamic earth pressures is very important. Conventional methods either use pseudo-static.

  13. 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.

  14. Dental pulp vascular permeability changes induced by dental bleaching

    Directory of Open Access Journals (Sweden)

    Cristiane da Costa

    2012-02-01

    Full Text Available Aiming to compare the effect of different light sources for dental bleaching on vascular permeability of dental pulps, forty-eight incisors were used. The bleaching agent (35 % hydrogen peroxide was activated by halogen light; LED (Light Emitting Diode or LED, followed by laser phototherapy (LPT (λ = 780 nm; 3 J/cm². After the bleaching procedures, the animals received an intra-arterial dye injection and one hour later were sacrificed. The teeth were diaphanized and photographed. The amount of blue stain content of each dental pulp was quantified using a computer imaging program. The data was statistically compared (p < 0.05. The results showed a significant higher (p < 0.01 dye content in the groups bleached with halogen light, compared with the control, LED and LED plus LPT groups. Thus, tooth bleaching activated by LED or LED plus LPT induces lesser resulted in increased vascular permeability than halogen light.

  15. Activity Sourcebook for Earth Science. Science Education Information Report.

    Science.gov (United States)

    Mayer, Victor J., Ed.

    Designed to provide teachers of earth science with activities and information that will assist them in keeping their curricula up to date, this publication contains activities grouped into six chapters. Chapter titles are: (1) Weather and Climate, (2) Oceans, (3) The Earth and Its Surface, (4) Plate Tectonics, (5) Uses of Space Photography, and…

  16. Bleaching of the discolored traumatized tooth

    DEFF Research Database (Denmark)

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

    2018-01-01

    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...

  17. Rare Earth-Activated Silica-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    C. Armellini

    2007-01-01

    Full Text Available Two different kinds of rare earth-activated glass-based nanocomposite photonic materials, which allow to tailor the spectroscopic properties of rare-earth ions: (i Er3+-activated SiO2-HfO2 waveguide glass ceramic, and (ii core-shell-like structures of Er3+-activated silica spheres obtained by a seed growth method, are presented.

  18. [Scalp burns induced by hair bleaching].

    Science.gov (United States)

    Bouschon, P; Bursztejn, A-C; Waton, J; Brault, F; Schmutz, J-L

    2018-03-14

    Hair bleaching is increasingly being carried out in hairdressing salons. The products used are a mixture of hydrogen peroxide and persulfates, both active chemical agents. Scalp burns secondary to hair bleaching are a traumatic adverse effect rarely discussed in publications that continue to be little known among healthcare professionals. We report the case of a 15-year-old girl with a plaque of scarring alopecia on the vertex. This lesion resulted from a deep burn following a hair-bleaching procedure. Healing took around 4 months, resulting in discomfort for our patient. This is a rare case of scarring alopecia following a basic chemical burn to the scalp. The oxidation reaction induced by the mixture of hydrogen peroxide and persulfates, prepared in a basic medium, causes bleaching of the melanin pigments in hair. The clinical presentation of a single, well limited, painful, oozing ulceration located at the vertex was similar to the other cases published in the literature. Although a chemical burning mechanism is most often incriminated, the procedure is always coupled with use of a heat source and associated thermal burn may occur. The delayed appearance of the lesion appears to be caused by the forming of surfactants by the hydrogen peroxide/persulfate mixture, resulting in slow dissolution of the oxidizing compounds within the stratum corneum. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  19. Determination of active oxygen content in rare earth peroxides

    International Nuclear Information System (INIS)

    Queiroz, Carlos A.S.; Abrao, Alcidio

    1993-01-01

    The content of active oxygen in rare earth peroxides have been determined after the dissolution of the samples with hydrocloridic acid in the presence of potassium iodide. The free generated iodine is titrated with sodium thiosulfate using starch as indicator. The oxidation of iodide to the free iodine indicates the presence of a higher valence state rare earth oxide, until now specifically recognized for the oxides of cerium (Ce O 2 ), praseodymium (Pr 6 O 1 1) and terbium (TB 4 O 7 ). recently the authors synthesized a new series of rare earth compounds, the peroxides. These new compounds were prepared by precipitating the rare earth elements complexed with carbonate ion by addition of hydrogen peroxide. the authors demonstrated that all rare earth elements, once solubilized by complexing with carbonate ion, are quantitatively precipitated as peroxide by addition of hydrogen peroxide. (author)

  20. Effect of light energy on peroxide tooth bleaching.

    Science.gov (United States)

    Luk, Karen; Tam, Laura; Hubert, Manfred

    2004-02-01

    Light-activated bleaching is a method of tooth whitening. The authors conducted a study to compare the whitening effects and tooth temperature changes induced by various combinations of peroxide bleaches and light sources. The authors randomly assigned 250 extracted human teeth halves into experimental groups (n = 10). A placebo gel (control), a 35 percent hydrogen peroxide or a 10 percent carbamide peroxide bleach was placed on the tooth surface and was irradiated with no light (control); a halogen curing light; an infrared, or IR, light; an argon laser; or a carbon dioxide, or CO2, laser. Color changes were evaluated immediately, one day and one week after treatment using a value-oriented shade guide and an electronic dental color analyzer. The outer enamel and inner dentin surface temperatures were monitored before and immediately after each 30-second application of light using a thermocouple thermometer. Color and temperature changes were significantly affected by an interaction of the bleach and light variables. The application of lights significantly improved the whitening efficacy of some bleach materials, but it caused significant temperature increases in the outer and inner tooth surfaces. The IR and CO2 laser lights caused the highest tooth temperature increases. Dentists performing an in-office bleaching technique with the use of an additional light source to accelerate tooth whitening should consider the specific bleaching agent being used, as well as the potential risks of heating teeth. A specific combination of bleach and light that demonstrates good color change and little temperature rise should be selected for in-office tooth bleaching.

  1. Atmospheric Pressure Plasma Jet as an Accelerator of Tooth Bleaching.

    Science.gov (United States)

    Santak, Vedran; Zaplotnik, Rok; Milosevic, Slobodan; Klaric, Eva; Tarle, Zrinka

    2014-12-01

    To study the effect of atmospheric pressure plasma (APP) jet as a potential accelerator of the degradation of hydrogen peroxide in bleaching gels which could lead to better and faster bleaching. 25 pastilles of hydroxylapatite were colored in green tea for 8 hours and were randomly divided into five groups (n = 5). The bleaching process was performed with 30% and 40% hydrogen peroxide (HP) gel alone and in conjunction with helium APP jet. During the bleaching treatment, optical emission spectroscopy and non-contact surface temperature measurement using pyrometer were performed. Color of the pastilles was determined by a red-green-blue (RGB) colorimeter. PH values of bleaching gels were measured before and after the plasma treatment on additional 10 pastilles using a pH meter with contact pH electrode. The color measurements of pastilles before and after the treatment showed that treatment with APP jet improved the bleaching effect by 32% and 15% in the case of 30% and 40% HP gel. Better results were obtained approximately six times faster than with a procedure suggested by the bleaching gel manufacturer. Optical emission spectroscopy proved that plasma has a chemically active role on the gel. After the APP treatment, pH values of bleaching gels dropped to about 50-75% of their initial value while the surface temperature increased by 8-10˚C above baseline. The use of plasma jet provides more effective bleaching results in a shorter period of time without a significant temperature increase which may cause damage of the surrounding tissue.

  2. Improvement in rice straw pulp bleaching effluent quality by incorporating oxygen delignification stage prior to elemental chlorine-free bleaching.

    Science.gov (United States)

    Kaur, Daljeet; Bhardwaj, Nishi K; Lohchab, Rajesh Kumar

    2017-10-01

    Environmental degradation by industrial and other developmental activities is alarming for imperative environmental management by process advancements of production. Pulp and paper mills are now focusing on using nonwood-based raw materials to protect forest resources. In present study, rice straw was utilized for pulp production as it is easily and abundantly available as well as rich in carbohydrates (cellulose and hemicelluloses). Soda-anthraquinone method was used for pulp production as it is widely accepted for agro residues. Bleaching process during paper production is the chief source of wastewater generation. The chlorophenolic compounds generated during bleaching are highly toxic, mutagenic, and bioaccumulative in nature. The objectives of study were to use oxygen delignification (ODL) stage prior to elemental chlorine-free (ECF) bleaching to reduce wastewater load and to study its impact on bleached pulp characteristics. ODL stage prior to ECF bleaching improved the optical properties of pulp in comparison to only ECF bleaching. When ODL stage was incorporated prior to bleaching, the tensile index and folding endurance of the pulp were found to be 56.6 ± 1.5 Nm/g and 140, respectively, very high in comparison to ECF alone. A potential reduction of 51, 57, 43, and 53% in BOD 3 , COD, color, and AOX, respectively was observed on adding the ODL stage compared to ECF only. Generation of chlorophenolic compounds was reduced significantly. Incorporation of ODL stage prior to bleaching was found to be highly promising for reducing the toxicity of bleaching effluents and may lead to better management of nearby water resources. Graphical abstract ᅟ.

  3. Coral reef bleaching: ecological perspectives

    Science.gov (United States)

    Glynn, P. W.

    1993-03-01

    Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (>95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt

  4. Rare earth activated phosphors for different applications

    International Nuclear Information System (INIS)

    Nazarov, Mihail

    2013-01-01

    For the purpose of development of highly energy-efficient light sources, one needs to design highly efficient green, red and yellow phosphors, which are able to absorb excitation energy and generate emissions. Using double activation, energy can be transferred from one luminescent activator to the other one, resulting in more efficient or brighter device operation. Co-activators can be added to a host material to change the color of the emitted light. The incorporation of Eu 3+ or Tb 3+ ions into the CaWO 4 crystal lattice modifies the luminescence spectrum due to the formation of the emission centers that generate the specific red and green light. Very efficient new red phosphors based on YnbO 4 and doped by Eu 3+ , Ga 3+ , Al 3+ allow recommend these materials as good candidates for different applications including LED and X-ray intensifying screens. For double activated TAG with Ce 3+ and Eu 3+ and for different mole ratio Ce/Eu the color temperature changes from 5500 K (0.331, 0.322) up to 4200 K (0.370, 0.381) and the light becomes 'warmer'. Application of TAG:Ce,Eu in the light emitting device shows the better chromaticity coordinates of luminescence and color rendering index of LEDs. Combination of Eu 2+ with Dy 3+ in SrAl 2 O 4 matrix allows us to create a material that emitted bright light for hours after ending the excitation. In this contribution we present our results on producing some efficient phosphors with improved luminescence properties for different applications: LED and X-ray intensifying screens, marine artificial reefs, biology and medicine. (authors)

  5. Board on Earth Sciences and Resources and its activities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    The Board on Earth Sciences and Resources (BESR) coordinates, the National Research Council`s advice to the federal government on solid-earth science issues. The board identifies opportunities for advancing basic research and understanding, reports on applications of earth sciences in such areas as disaster mitigation and resource utilization, and analyzes the scientific underpinnings and credibility of earth science information for resource, environmental and other applications and policy decision. Committees operating under the guidance of the Board conducts studies addressing specific issues within the earth sciences. The current committees are as follows: Committee on Geophysical and Environmental Data; Mapping Sciences Committee; Committee on Seismology; Committee on Geodesy; Rediscovering Geography Committee; Committee on Research Programs of the US Bureau of Mines. The following recent reports are briefly described: research programs of the US Bureau of Mines, first assessment 1994; Mount Rainier, active cascade volcano; the national geomagnetic initiative; reservoir class field demonstration program; solid-earth sciences and society; data foundation for the national spatial infrastructure; promoting the national spatial data infrastructure through partnerships; toward a coordinated spatial data infrastructure for the nation; and charting a course into the digital era; guidance to the NOAA`s nautical charting mission.

  6. Spitzer identification of potentially active Near-Earth Asteroids

    Science.gov (United States)

    Mommert, Michael; Trilling, David; Hora, Joseph; Smith, Howard; Chesley, Steve; Emery, Josh; Farnocchia, Davide; Fazio, Giovanni; Harris, Alan; Mueller, Migo

    2017-04-01

    The separation between asteroids and comets has become less clear with the discovery of a small group of asteroids that display comet-like activity. While the activity is attributed to different mechanisms, some objects seem to activate close to the Sun. Near-Earth Asteroids (NEAs) come close to the Earth and the Sun, constituting a natural laboratory for the study of thermally induced activity. Two NEA sub-populations are especially suspected of being potentially active: dormant comets and near-Sun asteroids. We propose 12.4 hrs of Spitzer IRAC observations of 3 near-Sun asteroids and one dormant comet (3552) Don Quixote, about which we have already published. Our goals are (1) to search for activity in Don Quixote, which showed CO/CO2 activity during its previous apparition and (2) to search for activity and measure the diameters and albedos of the near-Sun asteroids. In combination with a funded ground-based observing program, our results will provide significant legacy value to the investigation of activity in near-Earth asteroids.

  7. Sorting Recycled Trash: An Activity for Earth Day 2007

    Science.gov (United States)

    Harris, Mary E.; Harris, Harold H.

    2007-01-01

    Middle or high school students celebrate Earth Day on April 22, 2007 by participating in the activity to separate commingled recyclable trash to simulate sorting in a recycling center. Students would gain an appreciation for recyclable trash, after it is taken to a recycling center and learn about properties of recyclables.

  8. Cometary Activity in Near-Earth Asteroid Don Quixote

    NARCIS (Netherlands)

    Mommert, M.; Hora, J. L.; Harris, A. W.; Reach, W. T.; Mueller, M.; Thomas, C. A.; Emery, J. P.; Trilling, D. E.; Delbo', M.; Smith, H.

    2013-01-01

    The near-Earth object (NEO) population is thought to comprise a number of "dormant" short-period comets [1]. One of the most promising NEO candidates for a cometary origin is (3552) Don Quixote, due to its comet-like orbit and albedo. We present the discovery of cometary activity in (3552) Don

  9. Modeling bleaching of tomato derivatives at subzero temperatures.

    Science.gov (United States)

    Manzocco, Lara; Calligaris, Sonia; Nicoli, Maria Cristina

    2006-02-22

    This work was addressed to obtain a predictive model of the rate of bleaching in tomato derivatives at subzero temperatures. To this aim, a tomato puree was freeze-dried and equilibrated at increasing solid fractions. The bleaching rate was assessed by measuring tomato color during storage for up to 18 months at temperatures from -30 to 0 degrees C. The temperature dependence of the tomato-bleaching rate was neither predictable using the Arrhenius equation nor simply related to tomato physical state. The lack of a clear Arrhenius relation was attributed to the occurrence of temperature-dependent phenomena, such as ice crystallization and oxygen solubility modifications, which strongly changed the local concentration of reactants. A modified Arrhenius equation predicting the tomato-bleaching rate in the entire temperature range was proposed. Tomato concentration, and hence its physical state, affected the temperature dependence of bleaching, modifying apparent activation energy and frequency factor of the modified Arrhenius equation. In light of these considerations, a mathematical model was set up and validated to accurately predict the tomato-bleaching rate on the basis of only its concentration and storage temperature.

  10. 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)

  11. Board on Earth Sciences and Resources and its activities

    Energy Technology Data Exchange (ETDEWEB)

    de Souza, Dr. Anthony R.

    2000-02-23

    This 1999 annual report of the activities of the National Research Council's (NRC) Board on Earth Sciences and Resources (BESR) begins with an introduction to the Board. This report (1) lists activities of the Board sustained by Department of Energy support, (2) presents accomplishments of the Board, (3) describes current and proposed studies of the Board, and (4) provides a brief review of the Board's future plans.

  12. International Year of Planet Earth - Activities and Plans in Mexico

    Science.gov (United States)

    Alaniz-Alvarez, S.; Urrutia-Fucugauchi, J.

    2007-12-01

    IYPE started as a joint initiative by UNESCO and IUGS with participation of several geosciences organizations, and has developed into a major program in geosciences with inclusion of national committees. In this presentation we focus on current activities and plans in our country, and in the international activities. IYPE activities have concentrated in publications and organization of conferences and meetings. A book series on Earth Science Experiments for Children has been defined, with the first books published on "Atmospheric Pressure and Free Fall of Objects" and "Light and Colors". Following books are on "Standing on Archimedes" and "Foucault and the Climate". Books are distributed free to school children, with more than 10,000 copies given of first volume. Other publications include the special issues of El Faro science magazine edited by the National University, with last issue published and distributed electronically and in hard copies this August. Special events include Conference of IYPE Executive Director presented during the International Day of Science Museums in late May in Science Museum Universum. This was followed by a Planet Earth Week in the University. Current plans include an electronic open-access publication, additional publications of the Planet Earth series, articles and special issues in journals and magazines, and events on selected themes from the IYPE science program, particularly on Megacities, Hazards, Resources and Life. The metropolitan area of Mexico City, with around 20 million inhabitants presents special challenges, being at high altitude within an active tectonic and volcanic area requiring major efforts in water supply, water control, rains and waste disposal and management. Involvement in international activities includes translation into Spanish of IYPE publications and the participation in programs and activities. In addition to activities in the different countries, we consider that IYPE should result in initiatives for

  13. Earth

    CERN Document Server

    Carter, Jason

    2017-01-01

    This curriculum-based, easy-to-follow book teaches young readers about Earth as one of the eight planets in our solar system in astronomical terms. With accessible text, it provides the fundamental information any student needs to begin their studies in astronomy, such as how Earth spins and revolves around the Sun, why it's uniquely suitable for life, its physical features, atmosphere, biosphere, moon, its past, future, and more. To enhance the learning experience, many of the images come directly from NASA. This straightforward title offers the fundamental information any student needs to sp

  14. Neutron activation analysis of the rare earth elements in rocks from the earth's upper mantle and deep crust

    International Nuclear Information System (INIS)

    Stosch, H.-G.; Koetz, J.; Herpers, U.

    1986-01-01

    Three techniques for analyzing rare earth elements (REE) in geological materials are described, i.e. instrumental neutron activation analysis (INAA), neutron activation analysis with pre-irradiation chemical REE separation (PCS-NAA) and radiochemical neutron activation analysis (RNAA). The knowledge of REE concentrationd in eclogites, peridotites and minerals from the earth's lower crust and upper mantle is very useful in constraining their petrogenetic history. (author)

  15. Cometary Activity in Near-Earth Asteroid (3552) Don Quixote

    Science.gov (United States)

    Mommert, M.; Hora, J. L.; Harris, A. W.; Reach, W. T.; Mueller, M.; Thomas, C. A.; Emery, J. P.; Trilling, D. E.; Delbo', M.; Smith, H.

    2013-09-01

    The near-Earth object (NEO) population is thought to comprise a number of "dormant" short-period comets [1]. One of the most promising NEO candidates for a cometary origin is (3552) Don Quixote, due to its comet-like orbit and albedo. We present the discovery of cometary activity in (3552) Don Quixote based on thermal-infrared obser- vations made with the Spitzer Space Telescope. Our observations clearly show the presence of a coma and a tail which we identify as molecular line emission from CO2 and thermal emission from dust. Our discovery indicates that more NEOs may harbor volatiles than previously expected.

  16. Assessment of acute phase proteins and oxidative stress status of Nigerians using bleaching agents

    International Nuclear Information System (INIS)

    Akibinu, M.O.; Arinola, O.G.; Afolabi, K.A.

    2010-01-01

    The disruption of primary innate immune function of the epidermal layer of the skin accounts for the susceptibility of individuals using bleaching agents to localized or systemic infections. This subverted innate immunity in these people may lead to other pathological conditions. The resultant effects of skin bleaching and phagocytes activation in response to infections have not been studied in Nigerians using bleaching agents. The present study therefore assessed the levels of C-reactive protein (CRP), albumin, total antioxidant potential (TAP), total plasma peroxides (TPP), oxidative stress index (OSI) and malonaldehyde (MDA) in the users bleaching agents. Thirty (30) people who had used bleaching agents for average of 4.9 + 1.2 years participated in this study. They were recruited from various schools and markets within the city of Ibadan, Oyo State, Nigeria. Thirty apparently healthy staffs of University College Hospital Ibadan, Ibaadan, Nigeria, who had never used bleaching agents served as controls. All the subjects used for this study had no metabolic abnormality and tested negative to both HIV and hepatitis B infections. The mean value of TAP (p 0.20) when compared with the controls. Oxidative stress and chronic inflammation are possible consequences of skin bleaching. The users of skin bleaching agents may need antioxidant therapies to avert the risks of oxidative stress. (author)

  17. Active earth pressure model tests versus finite element analysis

    Directory of Open Access Journals (Sweden)

    Pietrzak Magdalena

    2017-01-01

    Full Text Available The purpose of the paper is to compare failure mechanisms observed in small scale model tests on granular sample in active state, and simulated by finite element method (FEM using Plaxis 2D software. Small scale model tests were performed on rectangular granular sample retained by a rigid wall. Deformation of the sample resulted from simple wall translation in the direction ‘from the soil” (active earth pressure state. Simple Coulomb-Mohr model for soil can be helpful in interpreting experimental findings in case of granular materials. It was found that the general alignment of strain localization pattern (failure mechanism may belong to macro scale features and be dominated by a test boundary conditions rather than the nature of the granular sample.

  18. Active earth pressure model tests versus finite element analysis

    Science.gov (United States)

    Pietrzak, Magdalena

    2017-06-01

    The purpose of the paper is to compare failure mechanisms observed in small scale model tests on granular sample in active state, and simulated by finite element method (FEM) using Plaxis 2D software. Small scale model tests were performed on rectangular granular sample retained by a rigid wall. Deformation of the sample resulted from simple wall translation in the direction `from the soil" (active earth pressure state. Simple Coulomb-Mohr model for soil can be helpful in interpreting experimental findings in case of granular materials. It was found that the general alignment of strain localization pattern (failure mechanism) may belong to macro scale features and be dominated by a test boundary conditions rather than the nature of the granular sample.

  19. Application of TAED/H2O2 system for low temperature bleaching of crude cellulose extracted from jute fiber

    Science.gov (United States)

    Wen, Zuoqiang; Zou, Linbo; Wang, Weiming

    2018-03-01

    Tetraacetylethylenediamine (TAED) activated hydrogen peroxide system had been applied for bleaching of crude cellulose extracted from jute fiber. Comparing with conventional hydrogen peroxide bleaching system, those results showed that bleaching temperature and time could be effectively reduced, and a preferable whiteness could be produced under faint alkaline condition. And the optimum conditions for activated bleaching system could be summarized as molar ratio of H2O2/TAED 1:0.7, pH 8, pure hydrogen peroxide 0.09 mol/L, temperature 70 °C and time 60min.

  20. 40 CFR 63.445 - Standards for the bleaching system.

    Science.gov (United States)

    2010-07-01

    ...) Bleaching systems bleaching pulp from kraft, sulfite, or soda pulping processes that use any chlorinated compounds; or (3) Bleaching systems bleaching pulp from mechanical pulping processes using wood or from any process using secondary or non-wood fibers, that use chlorine dioxide. (b) The equipment at each bleaching...

  1. EARTH OBSERVATION ACTIVITIES AND FUTURE PERSPECTIVES IN EGYPT

    Directory of Open Access Journals (Sweden)

    I. A. El-Magd

    2017-11-01

    Full Text Available Egypt was one of the first developing countries in Africa that used earth observation and remote sensing in various applications since 1970s. It has grown up in the last decades to build its own capacity in space science and technology that ended up by launching earth observation satellites. At the same time Egypt continued to develop the capacity in EO applications and contribute to the national development plans. In this domain NARSS, the governmental research institute that lead the EO and space applications has completed many research and development projects in EO applications in mineral resources exploration, coastal and marine resources, air quality, water resources management, food security, etc. This was via operational projects with the stakeholders and users to ensure sustainability and operation of the services. For example, NARSS has developed an operational system to monitor the national crop rice using EO information that capable to provide the actual land planted with rice and predict the yield. The system has enabled to provide recommendations for other plots of land that suitable for rice plantation. In the area of environmental hazards, many projects on the flash floods and the vulnerability to flash flood hazards were developed providing decision makers with vulnerability maps and Atlases on national level. Further details on the EO activities and future plans at NARSS, Egypt will be presented in this paper.

  2. Dentist-prescribed home bleaching: current status.

    Science.gov (United States)

    Dunn, J R

    1998-08-01

    White teeth have been an indicator of physical attractiveness throughout history. Only recently have we been able to whiten teeth with few side effects, making tooth bleaching a popular and effective dental treatment. The American Dental Association (ADA) has established guidelines on safety and effectiveness for tooth bleaching. External stains from aging or inherent dark color are more responsive to bleaching than internal stains. Dentist-prescribed home bleaching--including a careful dental exam, custom-fabricated trays, tacky high-viscosity gels, adequate instructions, and recall exams--has been shown to be an effective method for bleaching teeth. Trays can be worn overnight or during the day with similar effectiveness. The bleaching effect can last up to 3 years with more than 50% success.

  3. The active liquid Earth - importance of temporal and spatial variability

    Science.gov (United States)

    Arheimer, Berit

    2016-04-01

    The Planet Earth is indeed liquid and active - 71 percent of its surface is water-covered and this water never rests. Thanks to the water cycle, our planet's water supply is constantly moving from one place to another and from one form to another. Only 2.5% of the water is freshwater and it exists in the air as water vapor; it hits the ground as rain and snow; it flows on the surface from higher to lower altitudes in rivers, lakes, and glaciers; and it flows in the ground in soil, aquifers, and in all living organisms until it reaches the sea. On its way over the Earth's crust, some returns quickly to vapor again, while some is trapped and exposed to many "fill and spill" situations for a long journey. The variability in the water balance is crucial for hydrological understanding and modelling. The water cycle may appear simple, but magnitudes and rates in fluxes are very different from one place to another, resulting from variable drivers such as solar energy, precipitation and gravity in co-evolution with geology, soil, vegetation and fauna. The historical evolution, the temporal fluxes and diversity in space continue to fascinate hydrological scientists. Specific physical processes may be well known, but their boundary conditions, interactions and rate often remain unknown at a specific site and are difficult to monitor in nature. This results in mysterious features where trends in drivers do not match runoff, like the Sahelian Paradox or discharge to the Arctic Ocean. Humans have always interfered with the water cycle and engineering is fundamental for water regulation and re-allocation. Some 80% of the river flow from the northern part of the Earth is affected by fragmentation of the river channels by dams. In water management, there is always a tradeoff between upstream and downstream activities, not only regarding total water quantities but also for temporal patterns and water quality aspects. Sharing a water resource can generate conflicts but geopolitical

  4. 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...

  5. Determination of rare earth elements in biomonitors by neutron activation

    International Nuclear Information System (INIS)

    Figueiredo, Ana M.G.; Saiki, Mitiko; Ticianelli, R.B.; Domingos, M.; Alves, E.S.; Marcelli, M.P.

    2000-01-01

    The rare earth elements (REE) are becoming more and more important from the technological point of view, due to their increasing use in modern industry. Due to this fact, environmental contamination by REE may become significant, and little information are still available about biological effects of REE in plants, animals and human beings. The use of biomonitors to control environmental pollution has been an ecological and economical alternative in Europe and United Sates, to minimize the high costs of conventional equipment s. In the present paper, neutron activation analysis was employed to determine La, Ce, Nd, Sm, Eu, Tb, Yb and Lu in the lichen Canoparmelia texana and in Tillandsia usneoides, species that have been widely used as monitors of atmospheric pollution. The results showed an accumulation of REE in the biomonitors, indicating good possibilities of their utilization in the study of environmental contamination by REE. (author)

  6. 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.

  7. Workshop on Human Activity at Scale in Earth System Models

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Melissa R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aziz, H. M. Abdul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Coletti, Mark A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kennedy, Joseph H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nair, Sujithkumar S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Omitaomu, Olufemi A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-26

    Changing human activity within a geographical location may have significant influence on the global climate, but that activity must be parameterized in such a way as to allow these high-resolution sub-grid processes to affect global climate within that modeling framework. Additionally, we must have tools that provide decision support and inform local and regional policies regarding mitigation of and adaptation to climate change. The development of next-generation earth system models, that can produce actionable results with minimum uncertainties, depends on understanding global climate change and human activity interactions at policy implementation scales. Unfortunately, at best we currently have only limited schemes for relating high-resolution sectoral emissions to real-time weather, ultimately to become part of larger regions and well-mixed atmosphere. Moreover, even our understanding of meteorological processes at these scales is imperfect. This workshop addresses these shortcomings by providing a forum for discussion of what we know about these processes, what we can model, where we have gaps in these areas and how we can rise to the challenge to fill these gaps.

  8. 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. © 2014 John Wiley & Sons Ltd.

  9. THE BLEACHING SYNDROME: MANIFESTATION OF A POST ...

    African Journals Online (AJOL)

    User

    exception, Western ideals are an environmental force that disrupts the well-being of African descended women in particular, resulting in the Bleaching Syndrome. Although the literature acknowledges racism among the list of colonial pathologies, amidst idealization of light skin neglect of the Bleaching Syndrome has been ...

  10. Microhardness of demineralized enamel following home bleaching and laser-assisted in office bleaching

    Science.gov (United States)

    Ghanbarzadeh, Majid; Akbari, Majid; Hamzei, Haniye

    2015-01-01

    Background There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. Material and Methods Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot lesions. Enamel blocks were prepared and randomly assigned to two groups of 20 each. The first group underwent home bleaching with 15% carbamide peroxide which was applied for 8 hours a day over a period of 15 days. In the second group, in-office bleaching was performed by 40% hydrogen peroxide and powered by irradiation from an 810 nm gallium-aluminum-arsenide (GaAlAs) diode laser (CW, 2W). This process was performed for 3 sessions every seven days, in 15 days. The specimens were stored in Fusayama Meyer artificial saliva during the experiment. Surface microhardness was assessed before and after the bleaching therapies in both groups. Results Microhardness decreased significantly following both home bleaching and laser-assisted in-office bleaching (p<0.05). There were no significant differences in hardness values among the two groups either before (p=0.131) or after (p=0.182) the bleaching procedures. Conclusions Tooth whitening through home bleaching or laser-assisted in-office bleaching can result in a significant reduction in microhardness of white spot lesions. Therefore, it is suggested to take protective measures on bleached demineralized enamel. Key words:White spot lesion, bleaching, laser, microhardness, demineralized enamel, home bleaching, in-office bleaching. PMID:26330939

  11. BLEACHING IN VITAL TEETH: A LITERARY REVIEW

    Directory of Open Access Journals (Sweden)

    Felipe Fagundes Soares

    2007-12-01

    Full Text Available Tooth bleaching technique has presented a significant evolution, promoting higher satisfaction and comfort to the patients. Therefore, the aim of this study was to present the bleaching agents and the techniques, discussing advantages and disadvantages of each one, and the effect of these agents in the oral environment. The main agents used in the bleaching technique are the hydrogen peroxide and the carbamide peroxide, promoting the bleaching effect through oxidation of organic compounds. The application of these agents can be made at home or at a doctor office. During treatment, it may occur some adverse effects, such as tooth sensibility, increasing of dental porosity, and some interactions with the restorative material. However, these adverse effects can be eliminated or controlled when the treatment is executed under professional orientation. When the bleaching technique is well indicated and correctly conducted, it is associated with significantly positive results.

  12. Depletion Rate of Hydrogen Peroxide from Sodium Perborate Bleaching Agent.

    Science.gov (United States)

    Tran, Liliann; Orth, Rebecca; Parashos, Peter; Tao, Ying; Tee, Calvin W J; Thomas, Vineet Thenalil; Towers, Georgina; Truong, Diem Thuy; Vinen, Cynthia; Reynolds, Eric C

    2017-03-01

    Internal bleaching of discolored teeth uses sodium perborate reacting with water to form the active agent, hydrogen peroxide (H 2 O 2 ). Sodium perborate is replaced at varying time intervals depending on clinician preference and until esthetically acceptable results are achieved, but this is done without scientific basis. This study measured the depletion rate of hydrogen peroxide from sodium perborate as a bleaching agent. Two sodium perborate bleaching products (Odontobleach [Australian Dental Manufacturing, Kenmore Hills, Queensland, Australia] and Endosure Perborate Micro [Dentalife, Ringwood, Victoria, Australia]) and distilled deionized water mixtures at ratios of 25 μg/mL, 50 μg/mL, and 100 μg/mL were placed into sealed microtubes and incubated at 37°C. H 2 O 2 concentrations were measured at 23 time points over 4 weeks. Quantification of H 2 O 2 concentrations was obtained using a ferrothiocyanate oxidation reduction reaction followed by spectrophotometry readings. The H 2 O 2 concentration rapidly peaked within 27 hours and reached a plateau by about 3 days (75 hours). Low levels of H 2 O 2 were evident beyond 3 days and for at least 28 days. No significant differences were found between the 2 sodium perborate products. There was also no significant difference in the depletion rate between the different ratios. Based on the chemistry of H 2 O 2 depletion, the minimum replacement interval for the bleaching agent is 3 days. Frequent replacements of the perborate clinically may be unnecessary because of the continued presence of low H 2 O 2 levels for at least 28 days. Although these data cannot be extrapolated to the clinical situation, they set a baseline for further studies to address the many clinical variables influencing internal bleaching. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Speciation of rare earth elements in different types of soils in China

    International Nuclear Information System (INIS)

    Wang Lijun; Zhang Shen; Gao Xiaojiang; Liu Shujuan

    1997-01-01

    Contents, distribution patterns, physical and chemical speciation of rare earth elements (REEs) in laterite (tropical zone), red earth (middle subtripical earth), yellow brown soil (Northern subtripical earth), cinnamon soil (warm temperature zone), leached chernozem (temperate zone) and albic bleached soil (temperate zone) in China were determined with instrumental neutron activation analysis (INAA). Content and distribution patterns of ERRs are closely related to soil mechanical composition. In laterite, red earth, yellow brown soil and leached chernozem, REEs mainly enrich in fine grain particles or coarser grain partials while in clay particles no such enrichment was found. The distribution patterns of REEs in these soils are consistent with the REE features of their parent rocks. In all the six soils, REEs mainly exist in residual form, and with the increase of atomic number, intermediate REEs (IRRE) have lower proportions of residual form than light REEs (LREE) and heavy REEs (HREE). For the six unstable forms, water soluble form has the lowest proportion. The proportions of exchangeable form, carbonate and specific adsorption form are lower. The proportions of Fe-Min oxides form in different types of soils decrease gradually from Southern China to Northern China following the order: laterite > red earth > yellow brown soil > cinnamon soil, leached chernozem, albic bleached soil. Proportions of bound organic matters are higher and follow the order: Albic bleached soil > leached chernozem > red earth > laterite > yellow brown soil > cinnamon soil. The albic bleached soil has higher proportion of softly bound organic matter form. The leached chernozem has higher proportion of tightly bound organic matter form. Form of bound to organic matter in laterite is almost totally made up of form of softly bound to organic matter

  14. Earth observation space programmes, SAFISY activities, strategies of international organisations, legal aspects. Volume 3

    International Nuclear Information System (INIS)

    1992-01-01

    This volume is separated in four sessions. First part is on earth observation space programmes (international earth observation projects and international collaboration, the ERS-1, SPOT and PRIRODA programmes, the first ESA earth observation polar platform and its payload, the future earth observation remote sensing techniques and concepts). The second part is on SAFISY activities (ISY programmes, education and applications, demonstrations and outreach projects). The third part is on programme and strategies of international organisations with respect to earth observation from space. The fourth part is on legal aspects of the use of satellite remote sensing data in Europe. (A.B.). refs., figs., tabs

  15. Study of fish oil bleaching using the sodium bentonite through a factorial design

    OpenAIRE

    Marcia Regina Simões; Reinaldo Aparecido Bariccatti; Caio Guilherme Secco Souza; José Dilson Silva de Oliveira

    2011-01-01

    This work was a experimental design in order to optimize the process of bleaching of fish oil, using the sodium bentonite as adsorbent, from the influence of variables such as weight of sodium bentonite, the temperature process, thermal activation of sodium bentonite and time of agitation. It was then possible to fit a mathematical model with the influence of each variable in the process of bleaching of the oil. The response variable was the absorbance at 444 nm.

  16. Study of fish oil bleaching using the sodium bentonite through a factorial design

    Directory of Open Access Journals (Sweden)

    Marcia Regina Simões

    2011-06-01

    Full Text Available This work was a experimental design in order to optimize the process of bleaching of fish oil, using the sodium bentonite as adsorbent, from the influence of variables such as weight of sodium bentonite, the temperature process, thermal activation of sodium bentonite and time of agitation. It was then possible to fit a mathematical model with the influence of each variable in the process of bleaching of the oil. The response variable was the absorbance at 444 nm.

  17. Assessment of the process of cottonseed oil bleaching in hexane

    Directory of Open Access Journals (Sweden)

    Megahed, Ola A.

    2002-12-01

    Full Text Available This work has been initiated to assess the feasibility of bleaching cottonseed oil in miscella as a processing step next to alkali refining in miscella. Alkali refining of cottonseed oil in miscella has several advantages over conventional refining technologies with respect to oil quality, oil losses and process cost. Therefore, the process efficiency of the bleaching of cottonseed oil in presence of hexane (at a volumetric ratio of 1:1, has been studied and compared to that without solvent. The process efficiency has been evaluated according to the decolourization capacity, the oil losses on spent earth, the filtration rate of the oil from the clay and the acidity of the bleached oil as well as its peroxide content. The bleaching in presence of hexane was carried out at 25ºC whereas that by conventional bleaching at 110ºC. Different clay loads were used in each of the two bleaching techniques and the colour indices of the oils before and after bleaching determined in each case. The results were used to predict Freundlich adsorption equations for the oil pigments in both cases. These equations were then used to predict the colour of the oils obtained by bleaching of refined oils of different grades. The results have shown that oil decolourization is more efficient in presence of solvent when the starting oil is of an acceptable grade and the reverse is true for low grade oils. Also, the possibility of oil oxidation during bleaching is less in presence of solvent. Moreover, the bleaching in miscella has proved two other additional advantages over conventional bleaching. The filtration of oil from clay is much faster in miscella bleaching and the oil losses on spent earth is lower. This will be reflected on the overall process economy.Este trabajo ha sido iniciado para evaluar la viabilidad de la decoloración del aceite de semilla de algodón en miscela como un paso de procesado próximo a la refinación alcalina en miscela. La refinaci

  18. 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

  19. [Assessment of tooth bleaching efficacy with spectrophotometer].

    Science.gov (United States)

    Zhu, Wenhao; Liu, Chang; Pan, Jie

    2014-06-01

    To analyze the changes in CIE L*, a*, and b* at cervical, body, and incisal sites after tooth bleaching by using a spectrophotometer. Sixty-seven intact and healthy maxillary central incisors were in-vestigated. These incisors were darker than A3 according to the Vita Classical shade guide. The CIE tooth shade parameters L*, a*, and b* were simultaneously recorded at three tooth areas (cervical, body, and incisal) with a spectrophotometer before and after tooth bleaching (35%H2O2 coordinating with Beyond whitening accelerator irradiating). The shade dif-ferential (DeltaE) was calculated. ANOVA, paired t-test, and Pearson correlation analysis were used for data analysis. The efficacy rates of tooth bleaching were satisfactory, with 86.6%, 86.6%, and 85.1% in the cervical, body, and incisal sites, respectively. The average values of DeltaE were 5.09, 4.44, and 4.40 in the cervical, body, and incisal sites. Tooth bleaching significantly increased L* and significantly decreased a* and b* in all tooth areas (P spectrophotometer could objectively evaluate the whitening effect of tooth bleaching at the different tooth sites. The tooth bleaching system (35%H202 coordinating with Beyond whitening accelerator irradiating) exerts powerful bleaching actions in most of the tooth areas investigated. The order of tooth bleaching effectiveness is cervicalbody>incisal. Yellow coloration is decreased mainly at the cervical site, and brightness was increased mostly at theincisal site. The effectiveness of tooth bleaching increases as the baseline b* value increases.

  20. 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).

  1. From research to innovation: The case of biotechnical pulp bleaching

    Energy Technology Data Exchange (ETDEWEB)

    Miettinen, R.

    1996-05-01

    The paper studies the emergence and development of a research-based innovation, enzyme-aided bleaching of kraft pulp. The idea of a new bleaching method was formulated in a meeting at the Biotechnical Laboratory of Technical Research Centre of Finland (VTT) in January 1984. The method was based on the use of hemicellulases. The Biotechnology Laboratory has actively studied hemicellulases for several years and they were hence immediately available for experiments. The Biotechnology Laboratory collaborated with the Fibre Chemistry Laboratory of the Finnish Pulp and Paper Research Institute (FPPRI), which knew different kinds of pulps and was skilled in the analysis of their paper technical qualities. With this combination of knowledge the results were achieved without delay.

  2. Can marine cloud brightening reduce coral bleaching?

    OpenAIRE

    Latham, J; Kleypas, J; Hauser, R; Parkes, B; Gadian, A

    2013-01-01

    Increases in coral bleaching events over the last few decades have been largely caused by rising sea surface temperatures (SST), and continued warming is expected to cause even greater increases through this century. We use a Global Climate Model to examine the potential of marine cloud brightening (MCB) to cool oceanic surface waters in three coral reef provinces. Our simulations indicate that under doubled CO conditions, the substantial increases in coral bleaching conditions from current v...

  3. Effects of sponge bleaching on ammonia-oxidizing Archaea: distribution and relative expression of ammonia monooxygenase genes associated with the barrel sponge Xestospongia muta.

    Science.gov (United States)

    López-Legentil, Susanna; Erwin, Patrick M; Pawlik, Joseph R; Song, Bongkeun

    2010-10-01

    Sponge-mediated nitrification is an important process in the nitrogen cycle, however, nothing is known about how nitrification and symbiotic Archaea may be affected by sponge disease and bleaching events. The giant barrel sponge Xestospongia muta is a prominent species on Caribbean reefs that contains cyanobacterial symbionts, the loss of which results in two types of bleaching: cyclic, a recoverable condition; and fatal, a condition associated with the disease-like sponge orange band (SOB) syndrome and sponge death. Terminal restriction fragment length polymorphism (TRFLP) analyses, clone libraries, and relative mRNA quantification of ammonia monooxygenase genes (amoA) were performed using a RNA transcript-based approach to characterize the active ammonia-oxidizing Archaea (AOA) community present in bleached, non-bleached, and SOB tissues of cyclically and fatally bleached sponges. We found that non-bleached and cyclically bleached tissues of X. muta harbored a unique Crenarchaeota community closely related to those reported for other sponges. In contrast, bleached tissue from the most degraded sponge contained a Crenarchaeota community that was more similar to those found in sediment and sand. Although there were no significant differences in amoA expression among the different tissues, amoA expression was higher in the most deteriorated tissues. Results suggest that a shift in the Crenarchaeota community precedes an increase in amoA gene expression in fatally bleached sponges, while cyclic bleaching did not alter the AOA community structure and its amoA gene expression.

  4. Decadal Cycles of Earth Rotation, Mean Sea Level and Climate, Excited by Solar Activity

    Czech Academy of Sciences Publication Activity Database

    Chapanov, Y.; Ron, Cyril; Vondrák, Jan

    2017-01-01

    Roč. 14, č. 2 (2017), s. 241-250 ISSN 1214-9705 R&D Projects: GA ČR GA13-15943S Institutional support: RVO:67985815 Keywords : Earth rotation * solar activity * mean sea level Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 0.699, year: 2016

  5. Effect of rare earth cations on activity of type Y zeolites in ethylene transformations

    International Nuclear Information System (INIS)

    Amezhnova, G.N.; Zhavoronkov, M.N.; Dorogochinskij, A.Z.; Proskurin, A.L.; Shmailova, V.I.

    1984-01-01

    The ethylene transformations on type Y rare earth zeolites with high degrees of sodium exchange are studied. It is shown that rare earth cations increase zeolites activity with growth of electronoacceptor capacity. The ethylene oligomerization occurs on polyvalent cations while subsequent oligomer transformations - on hydroxyl groups of zeolites

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

    Science.gov (United States)

    Soares, Ana Flávia; Bombonatti, Juliana Fraga Soares; Alencar, Marina Studart; Consolmagno, Elaine Cristina; Honório, Heitor Marques; Mondelli, Rafael Francisco Lia

    2016-01-01

    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. PMID:27008254

  7. 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.

  8. 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.

  9. THE EFFECTS OF RARE EARTHS ON ACTIVITY AND SURFACE ...

    African Journals Online (AJOL)

    A series of Ru-RE/γ-AL2O3 (RE = Ce, Pr, La, Sm, Tb or Gd) and Ru/γ-AL2O3 catalysts were prepared by impregnation method. The influence of rare earths on the catalytic performance of Ru/γ-AL2O3 catalyst for the water gas shift reaction was studied. The catalysts were characterized by X-ray diffraction (XRD), ...

  10. Earth's mysterious atmosphere. ATLAS 1: Teachers guide with activities

    Science.gov (United States)

    1991-01-01

    One of our mission's primary goals is to better understand the physics and chemistry of our atmosphere, the thin envelope of air that provides for human life and shields us from the harshness of space. The Space Shuttle Atlantis will carry the ATLAS 1 science instruments 296 km above Earth, so that they can look down into and through the various layers of the atmosphere. Five solar radiometers will precisely measure the amount of energy the Sun injects into Earth's environment. The chemistry at different altitudes will be measured very accurately by five other instruments called spectrometers. Much of our time in the cockpit of Atlantis will be devoted to two very exciting instruments that measure the auroras and the atmosphere's electrical characteristics. Finally, our ultraviolet telescope will probe the secrets of fascinating celestial objects. This Teacher's Guide is designed as a detective story to help you appreciate some of the many questions currently studied by scientists around the world. Many complex factors affect our atmosphere today, possibly even changing the course of global climate. All of us who live on Earth must recognize that we play an ever-growing role in causing some of these changes. We must solve this great atmospheric mystery if we are to understand all these changes and know what to do about them.

  11. Redistribution Principle Approach for Evaluation of Seismic Active Earth Pressure Behind Retaining Wall

    Science.gov (United States)

    Maskar, A. D.; Madhekar, S. N.; Phatak, D. R.

    2017-11-01

    The knowledge of seismic active earth pressure behind the rigid retaining wall is very essential in the design of retaining wall in earthquake prone regions. Commonly used Mononobe-Okabe (MO) method considers pseudo-static approach. Recently there are many pseudo-dynamic methods used to evaluate the seismic earth pressure. However, available pseudo-static and pseudo-dynamic methods do not incorporate the effect of wall movement on the earth pressure distribution. Dubrova (Interaction between soils and structures, Rechnoi Transport, Moscow, 1963) was the first, who considered such effect and till date, it is used for cohesionless soil, without considering the effect of seismicity. In this paper, Dubrova's model based on redistribution principle, considering the seismic effect has been developed. It is further used to compute the distribution of seismic active earth pressure, in a more realistic manner, by considering the effect of wall movement on the earth pressure, as it is displacement based method. The effects of a wide range of parameters like soil friction angle (ϕ), wall friction angle (δ), horizontal and vertical seismic acceleration coefficients (kh and kv); on seismic active earth pressure (Kae) have been studied. Results are presented for comparison of pseudo-static and pseudo-dynamic methods, to highlight the realistic, non-linearity of seismic active earth pressure distribution. The current study results in the variation of Kae with kh in the same manner as that of MO method and Choudhury and Nimbalkar (Geotech Geol Eng 24(5):1103-1113, 2006) study. To increase in ϕ, there is a reduction in static as well as seismic earth pressure. Also, by keeping constant ϕ value, as kh increases from 0 to 0.3, earth pressure increases; whereas as δ increases, active earth pressure decreases. The seismic active earth pressure coefficient (Kae) obtained from the present study is approximately same as that obtained by previous researchers. Though seismic earth

  12. Fracture resistance of teeth submitted to several internal bleaching protocols.

    Science.gov (United States)

    Leonardo, Renato de Toledo; Kuga, Milton Carlos; Guiotti, Flávia Angélica; Andolfatto, Carolina; Faria-Júnior, Norberto Batista de; Campos, Edson Alves de; Keine, Kátia Cristina; Dantas, Andrea Abi Rached

    2014-03-01

    The aim of this study was to evaluate the fracture resistance of teeth submitted to several internal bleaching protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP), 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser or sodium perborate (SP). After endodontic treatment, fifty bovine extracted teeth were divided into five groups (n = 10): G1-unbleached; G2-35HP; G3-37CP; G4-15HPTiO2 photoactivated by LED-laser and G5-SP. In the G2 and G4, the bleaching protocol was applied in 4 sessions, with 7 days intervals between each session. In the G3 and G5, the materials were kept in the pulp teeth for 21 days, but replaced every 7 days. After 21 days, the teeth were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until teeth fracture. The data were submitted to ANOVA and Tukey tests (α = 5%). The 35HP, 37CP, 15HPTiO2 and SP showed similar fracture resistance teeth reduction (p > 0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p endodontically-treated teeth, but there were no differences between each other. There are several internal bleaching protocols using hydrogen peroxide in different concentrations and activation methods. This study evaluated its effects on fracture resistance in endodontically-treated teeth.

  13. 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

    International Nuclear Information System (INIS)

    Walverde, Debora Ayala

    2001-01-01

    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 * a * b * . (author)

  14. The Effect of Displacement Mode of Rigid Retaining Walls on Shearing Bands by Active Earth Pressure

    Directory of Open Access Journals (Sweden)

    A. Sekkel

    2013-10-01

    Full Text Available This work treats the physical modeling of failure mechanisms by active earth pressure. This last is developed by retaining wall movement. A lot of research showed that wall displacement has a significant effect on active earth pressure. A good comprehension of active earth pressure phenomenon and its failure mechanisms help us to better conceive retaining walls. The conception of a small-scale model allowed the realization of active earth pressure tests, while displacing the mobile wall toward the outside of the massif. The studied material is that of Schneebeli; light two-dimensional material made of cylindrical plastic rollers, simulating granular non-cohesive soil. The evolution of shearing zones under continuous and discontinuous displacement modes of mobile walls by correlation pictures allows the investigation of the localization of deformations and failure mechanisms.

  15. Temperament and perception of tooth bleaching results

    Directory of Open Access Journals (Sweden)

    Katarzyna Mehr

    2016-09-01

    Full Text Available Background . The neurophysiological process of perceiving the results of tooth bleaching requires the correct interaction between the central nervous system and the organs of sight. Exaggerated beliefs concerning defective facial features may enhance inner attitudes about one’s own color of dentition, as well as a feeling of dissatisfaction with the degree of leaching. Objectives. The study aimed to assess the degree of the patient satisfaction with the results of tooth bleaching in relation to their temperament. Material and methods. There were 68 generally healthy volunteers, aged 28–38 years, with external discolorations of the teeth. They had never undergone dental bleaching and their frontal teeth did not have any fillings. After clinical evaluation and the completion of formalities, the patients were asked to fill in Strelau’s temperament questionnaire. Questionnaires and visual status were assessed three times by three doctors: before bleaching, and then 24 hours and two weeks after the home-bleaching operation, which was done with the use of Opalescence (Ultradent in uniform sequence. Results . There were practically no adverse side results, except a periodic dentin hypersensitivity that occurred periodically in 44 patients. The results of the visual assessment performed by the physicians did not differ. The questionnaire data showed that women were more critical of the results in relation to the expectations. Among elancholics, full satisfaction was declared by 41%, whereas among sanguine people, full satisfaction was obtained by 85%. Satisfaction with the aesthetic results was associated with bleaching by at least 4 degrees. Conclusions . Patients’ temperament affects their subjective evaluation of the effectiveness of tooth bleaching, which should be taken into consideration in the patient’s individual dental treatment plan.

  16. Combined Bleaching Technique Using Low and High Hydrogen Peroxide In-Office Bleaching Gel.

    Science.gov (United States)

    Rezende, M; Ferri, L; Kossatz, S; Loguercio, A D; Reis, A

    2016-01-01

    The aim of this study was to evaluate the efficacy, color stability, risk, and intensity of tooth sensitivity (TS) of combined bleaching techniques performed with 20% or 35% hydrogen peroxide for an in-office protocol. Thirty patients were randomly divided into two groups and submitted to a single 45-minute in-office bleaching session with 35% hydrogen peroxide or 20% hydrogen peroxide. At-home bleaching was performed with 10% carbamide peroxide for two hours daily over the course of two weeks. The color was evaluated with the value-oriented shade guide Vita Classical at different periods up to 12 months after bleaching. Patients recorded the intensity of TS using a five-point verbal scale. Color change data were submitted to a two-way repeated-measures analysis of variance and Tukey test (α=0.05). The absolute risk and intensity of TS were compared with the Fisher exact test and Mann-Whitney test, respectively (α=0.05). On average, an effective and similar whitening of three units in shade guide was observed for both groups, which remained stable for 12 months. When both protocols were compared, the one with hydrogen peroxide 35% showed a higher risk (p=0.02) and intensity of TS (p=0.04). In regard to the TS intensity, no significant difference was observed up to 48 hours after in-office bleaching (p=0.09) and during the at-home bleaching phase of the study (p=0.71). The combined bleaching technique using at-home bleaching associated with in-office bleaching was effective and stable over the course of 12 months, regardless of the concentration of the hydrogen peroxide used for in-office bleaching. However, the protocol with 20% hydrogen peroxide produced lower risk and intensity of TS.

  17. Solar activity, tidal friction and the earth rotation over the last 2000 years

    International Nuclear Information System (INIS)

    Kiselev, V.M.

    1981-01-01

    The tidal retardations of the Earth rotation and orbital motion of the Moon on Dynamical Time are discussed. The secular deceleration of the lunar motion deduced from an analysis of the anciept and medieval eclipses is lapger thap that obtained from recent (telescopic) observations. This discrepancy is shown to vanish if the Earth acceleration due to secular change of solar activity is taken into consideration. Therefore, one may suggest that the mean tidal friction has remained essentially constant over the last two millennia. Nontidal variations of the Earth rotation velocity in the historical past as well as at present time are shown to be caused by solar activity changes [ru

  18. Study on the Seismic Active Earth Pressure by Variational Limit Equilibrium Method

    Directory of Open Access Journals (Sweden)

    Jiangong Chen

    2016-01-01

    Full Text Available In the framework of limit equilibrium theory, the isoperimetric model of functional extremum regarding the seismic active earth pressure is deduced according to the variational method. On this basis, Lagrange multipliers are introduced to convert the problem of seismic active earth pressure into the problem on the functional extremum of two undetermined function arguments. Based on the necessary conditions required for the existence of functional extremum, the function of the slip surface and the normal stress distribution on the slip surface is obtained, and the functional extremum problem is further converted into a function optimization problem with two undetermined Lagrange multipliers. The calculated results show that the slip surface is a plane and the seismic active earth pressure is minimal when the action point is at the lower limit position. As the action point moves upward, the slip surface becomes a logarithmic spiral and the corresponding value of seismic active earth pressure increases in a nonlinear manner. And the seismic active earth pressure is maximal at the upper limit position. The interval estimation constructed by the minimum and maximum values of seismic active earth pressure can provide a reference for the aseismic design of gravity retaining walls.

  19. Comparison between traditional and laser bleaching treatment

    Science.gov (United States)

    Cesar, Ilene C. R.; Redigolo, Marcela L.; Liporoni, Priscila C. S.; Munin, Egberto

    2001-10-01

    Fifteen human embedded third molars were used in this in vitro study to evaluate the effects of two bleaching products associated or not with Argon laser application. The samples received a cervical-apical cut and were longitudinally cut into 4 parts resulting in 75 specimens. These parts were divided at random into 5 groups and submitted to the traditional power bleaching procedure for enamel. Group 1 was separated as a control group. Group 2 was exposed to 37 % carbamide peroxide bleaching solution and developed with an Argon laser application. The same solution was used in Group 3 but the bleaching was developed with an halogen lamp irradiation. 35 % carbamide peroxide were used in Groups 4 and 5. One was developed as Group 2 and the other as Group 3. The samples were analyzed under a photoreflectance experiment. We observed that Group 2 presented more white spectra than Group 3. However, Groups 4 and 5 showed the same results independent of the use of the laser or the halogen lamp for the light curing. Comparing both bleaching products, the 35 % carbamide peroxide was more efficient on its purposes than the other one.

  20. A Chemical Approach to Mitigate Coral Bleaching

    Science.gov (United States)

    Marty-Rivera, M.; Yudowski, G.

    2016-02-01

    Changes in sea surface temperature and irradiance can induce bleaching and increase mortality in corals. Coral bleaching occurs when symbiotic algae living inside the coral is degraded or expelled, reducing the availability of energetic resources. Oxidative stress has been suggested as a possible molecular mechanism triggering bleaching. We hypothesized that reduction of reactive oxygen species (ROS) during stress could mitigate or prevent coral bleaching. We utilized the coral Porites Astreoides as our model to test the effects of two natural antioxidants, catechin and Resveratrol, on thermally induced bleaching. Coral fragments were exposed to four treatments: high temperature (32°C), high temperature plus antioxidants (1μM), ambient temperature (25°C), or ambient temperature (25°C) plus antioxidant for four days. A total of 8 corals were used per treatment. We measured several photobiological parameters, such as maximum quantum yield and light curves to assess the viability of symbiodinium spp. after thermal stress in the presence of antioxidants. Preliminary experiments on a model species, the sea anemone Aiptasia pallida and corals, showed that exposure to antioxidants reduced intracellular levels of ROS. Additionally, antioxidant-treated anemones showed higher photosynthetic efficiency (67%) than those exposed to high-temperature alone.

  1. 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...... was several times higher than net sedimentation. We propose that tidal channel sediment is bleached either on the tidal flat before it is transported to the tidal channels and incorporated in channel-fill successions or, alternatively, on the shallow intertidal part of the channel banks. Based...

  2. Side effects of external tooth bleaching

    DEFF Research Database (Denmark)

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

    2013-01-01

    Objective The study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects. Design Multi-centre, questionnaire-based prospective study with follow-ups at around 14 days and around one year post-treatment. Setting......-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 effects...... 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...

  3. 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

  4. Individual activity coefficients of single ionic species of alkaline earth halogenides, alkaline earth perchlorates, and uranyl perchlorate at 25 0C in aqueous solutions

    International Nuclear Information System (INIS)

    Ferse, A.

    1981-01-01

    The individual activity coefficients of the single ionic species of alkaline-earth haloides, alkaline earth perchlorates and uranylic perchlorate, resp., at 25 0 C in aqueous solution are calculated and presented up to the concentration of about m = 4 mol/kg. The individual activity coefficients of the alkaline-earth ions pass mostly as a function of the concentration through a steep minimum and decrease from Mg 2+ to Ba 2+ . The individual activity coefficients of the anions pass generally as a function of the concentration through a marked flat minimum, but they increase - the complex perchlorate ions excepted - only a little above 1. (author)

  5. Tooth Bleaching: Current Concepts of the Procedure in Cosmetic ...

    African Journals Online (AJOL)

    Less caustic agents more recently introduced, in the late 1900s, have revived the interest of the dental profession in the art of tooth bleaching. These agents are now being packaged as bleaching kits, which may be used for in-office bleaching by the dentist or used at home by the patient under the supervision of the dentist.

  6. Effects of bleaching wastewater irrigation on soil quality of constructed reed wetlands

    Directory of Open Access Journals (Sweden)

    Cheng Ding

    2016-10-01

    Full Text Available Constructed reed wetland microcosms (CRWs in a lab of east China have been irrigated with bleaching wastewater per month for a reed growth season. The soil physicochemical properties, enzyme activities (i.e. urease, invertase, polyphenol oxidase, alkaline phosphatase and cellulase and soil microbial diversity were assayed before and after the exposure experiment. Compared to the river water irrigated controls (CKs, bleaching wastewater application has no marked influence on soil pH, but significantly increased soil Na+, total halogen and absorbable organic halogen (AOX contents, which induced the increasing of soil electrical conductivity. Furthermore, soil enzyme activities displayed significant variation (except for polyphenol oxidase. Bleaching wastewater irrigation decreased Sorenson’s pairwise similarity coefficient (Cs, which indicated the changes of the structure of bacterial and fungal communities. However, only the diversity of bacterial community was inhibited and has no effect on the diversity of fungal community, as evidenced by the calculated Shannon–Wiener index (H.

  7. Activation analysis of trace amounts of rare earth in high purity tantalum

    International Nuclear Information System (INIS)

    Ishibashi, Wataru; Saito, Shinichi; Hirayama, Tooru.

    1975-01-01

    It is necessary to separate rare earth from tantalum by rapid methods in order to remove effects of a strong radioactivity and a short half-life. Tantalum is extracted with 10%N-lauryl (trialkylmethyl) amino-benzene pre-equilibrated with a solution of 9 M hydrochloric and 0.15 M hydrofluoric acid. A non-radioactive rare earth element is added to this aqueous solution, a precipitate of trace amounts of radioactive rare earth in aqueous solution is formed by this addition of rare earth. Some factors in the determination are: 1) the effect of the irradiation position of the sample in the atomic reactor, 2) the effect on the extraction with 10%N-lauryl (trialkylmethyl) amino-benzene for the radioactive rare earth, 3) the effect of the concentration of hydrofluoric acid, ammonia water and nitric acid on co-precipitation. As a result of the investigation we obtained the following satisfactory results: 1) Rare earth was not effected by the extraction of tantalum with 10%N-lauryl (trialkylmethyl) amino-benzene. 2) The recovery of rare earth by co-precipitation increases when an ammonium ion coexists, and when the concentration of hydrofluoric acid decreases, but the recovery decreases with the increase of nitric acid concentration. 3) The time required for the extraction is 9 hours. In case of determination for dysprosium, tantalum extracted with 10%N-lauryl (trialkylmethyl) amino-benzene before activation and the time for separation is 2 hours. (auth.)

  8. Earth-Space Science Activity Syllabus for Elementary and Junior High School Teachers of Science.

    Science.gov (United States)

    Maier, Jack; And Others

    This syllabus is a collection of earth-space science laboratory activities and demonstrations intended for use at the elementary and junior high school levels. The activities are grouped into eight subject sections: Astronomy, Light, Magnetism, Electricity, Geology, Weather, Sound, and Space. Each section begins with brief background information,…

  9. Exploring Connections Between Earth Science and Biology - Interdisciplinary Science Activities for Schools

    Science.gov (United States)

    Vd Flier-Keller, E.; Carolsfeld, C.; Bullard, T.

    2009-05-01

    To increase teaching of Earth science in schools, and to reflect the interdisciplinary nature and interrelatedness of science disciplines in today's world, we are exploring opportunities for linking Earth science and Biology through engaging and innovative hands-on science activities for the classroom. Through the NSERC-funded Pacific CRYSTAL project based at the University of Victoria, scientists, science educators, and teachers at all levels in the school system are collaborating to research ways of enriching the preparation of students in math and science, and improving the quality of science education from Kindergarten to Grade 12. Our primary foci are building authentic, engaging science experiences for students, and fostering teacher leadership through teacher professional development and training. Interdisciplinary science activities represent an important way of making student science experiences real, engaging and relevant, and provide opportunities to highlight Earth science related topics within other disciplines, and to expand the Earth science taught in schools. The Earth science and Biology interdisciplinary project builds on results and experiences of existing Earth science education activities, and the Seaquaria project. We are developing curriculum-linked activities and resource materials, and hosting teacher workshops, around two initial areas; soils, and marine life and the fossil record. An example activity for the latter is the hands-on examination of organisms occupying the nearshore marine environment using a saltwater aquarium and touch tank or beach fieldtrip, and relating this to a suite of marine fossils to facilitate student thinking about representation of life in the fossil record e.g. which life forms are typically preserved, and how are they preserved? Literacy activities such as fossil obituaries encourage exploration of paleoenvironments and life habits of fossil organisms. Activities and resources are being tested with teachers

  10. Measurement of chemical activities of rare earths (RE: Ce, Pr, Sm and Eu) in cadmium alloy

    International Nuclear Information System (INIS)

    Ghosh, Sajal; Ganesan, Rajesh; Sridharan, R.; Gnanasekaran, T.

    2015-01-01

    Activity of rare earth (RE) elements, Ce, Pr, Sm and Eu is measured in each of the cadmium rich binary alloys of RE, by making use of a molten salt based electrochemical cell. The binary alloy consists of a mixture of cadmium rich intermetallic compound and a liquid phase of known composition. Four independent cells are constructed; one for each of the rare earth elements and electromotive force (EMF) is measured as a function of temperature for each cell, respectively. Partial molar Gibbs energy of these rare earth metals in liquid cadmium is derived from the EMF output over a temperature range. Gibbs energy of formation of CeCd 11 , PrCd 11, SmCd 6 and EuCd 11 are deduced from the measured EMF values and the reported literature data on the solubility of rare earth elements in liquid cadmium. - Highlights: • Activities of rare earth (RE) elements such as Ce, Pr, Sm and Eu were measured as a function of temperature in cadmium rich biphasic mixture. • Partial molar Gibbs energies of these rare earths in liquid cadmium were derived over a temperature range. • Gibbs energy of formation of CeCd 11 , PrCd 11, SmCd 6 and EuCd 11 were derived.

  11. Variables and potential models for the bleaching of luminescence signals in fluvial environments

    Science.gov (United States)

    Gray, Harrison J.; Mahan, Shannon

    2015-01-01

    Luminescence dating of fluvial sediments rests on the assumption that sufficient sunlight is available to remove a previously obtained signal in a process deemed bleaching. However, luminescence signals obtained from sediment in the active channels of rivers often contain residual signals. This paper explores and attempts to build theoretical models for the bleaching of luminescence signals in fluvial settings. We present two models, one for sediment transported in an episodic manner, such as flood-driven washes in arid environments, and one for sediment transported in a continuous manner, such as in large continental scale rivers. The episodic flow model assumes that the majority of sediment is bleached while exposed to sunlight at the near surface between flood events and predicts a power-law decay in luminescence signal with downstream transport distance. The continuous flow model is developed by combining the Beer–Lambert law for the attenuation of light through a water column with a general-order kinetics equation to produce an equation with the form of a double negative exponential. The inflection point of this equation is compared with the sediment concentration from a Rouse profile to derive a non-dimensional number capable of assessing the likely extent of bleaching for a given set of luminescence and fluvial parameters. Although these models are theoretically based and not yet necessarily applicable to real-world fluvial systems, we introduce these ideas to stimulate discussion and encourage the development of comprehensive bleaching models with predictive power.

  12. 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.

  13. Electro-kinetic Separation of Rare Earth Elements Using a Redox-Active Ligand.

    Science.gov (United States)

    Fang, Huayi; Cole, Bren E; Qiao, Yusen; Bogart, Justin A; Cheisson, Thibault; Manor, Brian C; Carroll, Patrick J; Schelter, Eric J

    2017-10-16

    Purification of rare earth elements is challenging due to their chemical similarities. All of the deployed separation methods rely on thermodynamic properties, such as distribution equilibria in solvent extraction. Rare-earth-metal separations based on kinetic differences have not been examined. Herein, we demonstrate a new approach for rare-earth-element separations by exploiting differences in the oxidation rates within a series of rare earth compounds containing the redox-active ligand [{2-(tBuN(O))C 6 H 4 CH 2 } 3 N] 3- . Using this method, a single-step separation factor up to 261 was obtained for the separation of a 50:50 yttrium-lutetium mixture. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Electro-kinetic separation of rare earth elements using a redox-active ligand

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Huayi; Cole, Bren E.; Qiao, Yusen; Bogart, Justin A.; Cheisson, Thibault; Manor, Brian C.; Carroll, Patrick J.; Schelter, Eric J. [Department of Chemistry, University of Pennsylvania, Philadelphia, PA (United States)

    2017-10-16

    Purification of rare earth elements is challenging due to their chemical similarities. All of the deployed separation methods rely on thermodynamic properties, such as distribution equilibria in solvent extraction. Rare-earth-metal separations based on kinetic differences have not been examined. Herein, we demonstrate a new approach for rare-earth-element separations by exploiting differences in the oxidation rates within a series of rare earth compounds containing the redox-active ligand [{2-(tBuN(O))C_6H_4CH_2}{sub 3}N]{sup 3-}. Using this method, a single-step separation factor up to 261 was obtained for the separation of a 50:50 yttrium-lutetium mixture. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Activation and discovery of earth-abundant metal catalysts using sodium tert-butoxide.

    Science.gov (United States)

    Docherty, Jamie H; Peng, Jingying; Dominey, Andrew P; Thomas, Stephen P

    2017-06-01

    First-row, earth-abundant metals offer an inexpensive and sustainable alternative to precious-metal catalysts. As such, iron and cobalt catalysts have garnered interest as replacements for alkene and alkyne hydrofunctionalization reactions. However, these have required the use of air- and moisture-sensitive catalysts and reagents, limiting both adoption by the non-expert as well as applicability, particularly in industrial settings. Here, we report a simple method for the use of earth-abundant metal catalysts by general activation with sodium tert-butoxide. Using only robust air- and moisture-stable reagents and pre-catalysts, both known and, significantly, novel catalytic activities have been successfully achieved, covering hydrosilylation, hydroboration, hydrovinylation, hydrogenation and [2π+2π] alkene cycloaddition. This activation method allows for the easy use of earth-abundant metals, including iron, cobalt, nickel and manganese, and represents a generic platform for the discovery and application of non-precious metal catalysis.

  16. The 2018 Meteor Shower Activity Forecast for Earth Orbit

    Science.gov (United States)

    Moorhead, Althea; Cooke, Bill; Moser, Danielle

    2017-01-01

    A number of meteor showers - the Ursids, Perseids, Leonids, eta Aquariids, Orionids, Draconids, and Andromedids - are predicted to exhibit increased rates in 2018. However, no major storms are predicted, and none of these enhanced showers outranks the typical activity of the Arietids, Southern delta Aquariids, and Geminids at small particle sizes. The MSFC stream model1 predicts higher than usual activity for the Ursid meteor shower in December 2018. While we expect an increase in activity, rates will fall short of the shower's historical outbursts in 1945 and 1986 when the zenithal hourly rate (ZHR) exceeded 100. Instead, the expected rate for 2018 is around 70. The Perseids, Leonids, eta Aquariids, and Orionids are expected to show mild enhancements over their baseline activity level in 2018. In the case of the Perseids, we may see an additional peak in activity a few hours before the traditional peak, but we do not expect activity levels as high as those seen in 2016 and 2017. The eta Aquariids and Orionids, which belong to a single meteoroid stream generated by comet 1P/Halley, are thought to have a 12-year activity cycle and are currently increasing in activity from year to year. Finally, we may see minor outbursts of the Draconids and Andromedids in 2018. Both showers have been difficult to model and have produced unexpected outbursts in recent years (the Draconids in 2012 and the Andromedids in 2011 and 2013). The Andromedids may produce two peaks, both of which are listed in Table 2. This document is designed to supplement spacecraft risk assessments that incorporate an annual averaged meteor shower flux (as is the case with all NASA meteoroid models). Results are presented relative to this baseline and are weighted to a constant kinetic energy. Two showers - the Daytime Arietids (ARI) and the Geminids (GEM) - attain flux levels approaching that of the baseline meteoroid environment for 0.1-cm-equivalent meteoroids. This size is the threshold for structural

  17. In-Office Bleaching During Orthodontic Treatment.

    Science.gov (United States)

    Gomes, Mauricio Neves; Dutra, Hélio; Morais, Alexandre; Sgura, Ricardo; Devito-Moraes, André Guaraci

    2017-04-01

    To demonstrate that it is possible to pursue teeth whitening treatment protocols during orthodontic treatment with no esthetic loss. Many patients undergoing orthodontic treatment desire to have a straight and well aligned dentition, but also whiter teeth. For many years, it was believed that carrying out a whitening treatment with positioned orthodontic brackets in place would result in localized spots on the enamel labial surfaces of teeth. However, a deeper understanding of the bleaching process suggests that the oxidation caused by products, which results from hydrogen peroxide decomposition, are able to diffuse peripherally into the tooth structure and reach even that under the cemented brackets. Two in-office-bleaching treatments were performed in patients using orthodontic fixed braces in two or three 40-minute sessions using a 35% hydrogen peroxide. In-office bleaching is possible and effective, even with orthodontic brackets in position. The teeth were successfully bleached despite the presence of brackets. All biological criteria have been fulfilled satisfying patients' expectations of aligned and whitened teeth in less time than if treatments had been performed separately, with satisfactory results and no esthetic loss. The whitening of teeth is possible during orthodontic treatment with fixed braces without any esthetic loss. The in-office bleaching treatment with brackets in position also may act as a motivation factor, preventing patient withdrawal or treatment interruption. Therefore, at the end of the orthodontic treatment, the patient is able to display an aligned, functional and whitened smile. (J Esthet Restor Dent 29:83-92, 2017). © 2016 Wiley Periodicals, Inc.

  18. 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

    2017-03-15

    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.

  19. 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.

  20. Active microwave remote sensing of earth/land, chapter 2

    Science.gov (United States)

    1975-01-01

    Geoscience applications of active microwave remote sensing systems are examined. Major application areas for the system include: (1) exploration of petroleum, mineral, and ground water resources, (2) mapping surface and structural features, (3) terrain analysis, both morphometric and genetic, (4) application in civil works, and (5) application in the areas of earthquake prediction and crustal movements. Although the success of radar surveys has not been widely publicized, they have been used as a prime reconnaissance data base for mineral exploration and land-use evaluation in areas where photography cannot be obtained.

  1. The 2017 Meteor Shower Activity Forecast for Earth Orbit

    Science.gov (United States)

    Moorhead, Althea; Cooke, Bill; Moser, Danielle

    2017-01-01

    Most meteor showers will display typical activity levels in 2017. Perseid activity is expected to be higher than normal but less than in 2016; rates may reach 80% of the peak ZHR in 2016. Despite this enhancement, the Perseids rank 4th in flux for 0.04-cm-equivalent meteoroids: the Geminids (GEM), Daytime Arietids (ARI), and Southern delta Aquariids (SDA) all produce higher fluxes. Aside from heightened Perseid activity, the 2017 forecast includes a number of changes. In 2016, the Meteoroid Environment Office used 14 years of shower flux data to revisit the activity profiles of meteor showers included in the annual forecast. Both the list of showers and the shape of certain major showers have been revised. The names and three-letter shower codes were updated to match those in the International Astronomical Union (IAU) Meteor Data Center, and a number of defunct or insignificant showers were removed. The most significant of these changes are the increased durations of the Daytime Arietid (ARI) and Geminid (GEM) meteor showers. This document is designed to supplement spacecraft risk assessments that incorporate an annual averaged meteor shower flux (as is the case with all NASA meteor models). Results are presented relative to this baseline and are weighted to a constant kinetic energy. Two showers - the Daytime Arietids (ARI) and the Geminids (GEM) - attain flux levels approaching that of the baseline meteoroid environment for 0.1-cm-equivalent meteoroids. This size is the threshold for structural damage. These two showers, along with the Quadrantids (QUA) and Perseids (PER), exceed the baseline flux for 0.3-cm-equivalent particles, which is near the limit for pressure vessel penetration. Please note, however, that meteor shower fluxes drop dramatically with increasing particle size. As an example, the Arietids contribute a flux of about 5x10(exp -6) meteoroids m(exp -2) hr-1 in the 0.04-cm-equivalent range, but only 1x10(exp -8) meteoroids m(sub -2) hr-1 for the 0

  2. Kraft Pulp Bleaching and Delignification by Dikaryons and Monokaryons of Trametes versicolor

    Science.gov (United States)

    Addleman, Katherine; Archibald, Frederick

    1993-01-01

    The ability of 10 dikaryotic and 20 monokaryotic strains of Trametes (Coriolus) versicolor to bleach and delignify hardwood and softwood kraft pulps was assessed. A dikaryon (52P) and two of its mating-compatible monokaryons (52J and 52D) derived via protoplasting were compared. All three regularly bleached hardwood kraft pulp more than 20 brightness points (International Standards Organization) in 5 days and softwood kraft pulp the same amount in 12 days. Delignification (kappa number reduction) by the dikaryon and the monokaryons was similar, but the growth of the monokaryons was slower. Insoluble dark pigments were commonly found in the mycelium, medium, and pulp of the dikaryon only. Laccase and manganese peroxidase (MnP) but not lignin peroxidase activities were secreted during bleaching by all three strains. Their laccase and MnP isozyme patterns were compared on native gels. No segregation of isozyme bands between the monokaryons was found. Hardwood kraft pulp appeared to adsorb several laccase isozyme bands. One MnP isozyme (pI, 3.2) was secreted in the presence of pulp by all three strains, but a second (pI, 4.9) was produced only by 52P. A lower level of soluble MnP activity in one monokaryon (52D) was associated with reduced bleaching ability and a lower level of methanol production. Since monokaryon 52J bleached pulp better than its parent dikaryon 52P, especially per unit of biomass, this genetically simpler monokaryon will be the preferred subject for further genetic manipulation and improvement of fungal pulp biological bleaching. Images PMID:16348851

  3. Rotation of the Earth, solar activity and cosmic ray intensity

    Energy Technology Data Exchange (ETDEWEB)

    Barlyaeva, T.; Bard, E. [Aix-Marseille Univ., CNRS, IRD, Aix-en-Provence (France). CEREGE, College de France; Abarca-del-Rio, R. [Universidad de Concepcion (UDEC) (Chile). Dept. de Geofisica (DGEO)

    2014-10-01

    We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

  4. Activation analysis of yttrium in rare earth ores using 15 MeV bremsstrahlung

    International Nuclear Information System (INIS)

    Hoang Dac Luc

    1992-01-01

    Yttrium concentration in rare earth ores was determined via the isomeric state 8 9 m Y by photo activation using 15MeV bremsstrahlung from a microtron. Correction for residual dead time was used. Interference from zirconium was taken into account. The sensitivity of determination was 10 -5 g/g. (author). 2 refs; 3 figs; 2 tabs

  5. Neutron activation analysis in geological samples containing rare earths, uranium and thorium

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.; Figueiredo, A.M.G.; Berretta, J.R.; Soares, J.C.A.C.R.; Fratin, L.; Goncales, O.L.; Botelho, S.

    1990-01-01

    The neutron activation analysis method was used for determination of rare earths, uranium, thorium and other tracks in geological samples, under the geological standard JB-1 (Geological Survey of Japan) and S-8 and S-13 (IAEA). (L.C.J.A.)

  6. Thermographic and spectrophotometric analysis of the extrinsic tooth bleaching using a diode laser and a LED system. In vitro

    International Nuclear Information System (INIS)

    Micheli, Paola Racy de

    2004-01-01

    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)

  7. 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.

  8. 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 ( μ TBS) 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 (H 2 O 2 ) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H 2 O 2 -containing titanium dioxide (TiO 2 ) (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 μ TBS 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 μ TBS 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 H 2 O 2 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% H 2 O 2 bleaching.

  9. A multi-trait systems approach reveals a response cascade to bleaching in corals.

    Science.gov (United States)

    Gardner, Stephanie G; Raina, Jean-Baptiste; Nitschke, Matthew R; Nielsen, Daniel A; Stat, Michael; Motti, Cherie A; Ralph, Peter J; Petrou, Katherina

    2017-12-07

    Climate change causes the breakdown of the symbiotic relationships between reef-building corals and their photosynthetic symbionts (genus Symbiodinium), with thermal anomalies in 2015-2016 triggering the most widespread mass coral bleaching on record and unprecedented mortality on the Great Barrier Reef. Targeted studies using specific coral stress indicators have highlighted the complexity of the physiological processes occurring during thermal stress, but have been unable to provide a clear mechanistic understanding of coral bleaching. Here, we present an extensive multi-trait-based study in which we compare the thermal stress responses of two phylogenetically distinct and widely distributed coral species, Acropora millepora and Stylophora pistillata, integrating 14 individual stress indicators over time across a simulated thermal anomaly. We found that key stress responses were conserved across both taxa, with the loss of symbionts and the activation of antioxidant mechanisms occurring well before collapse of the physiological parameters, including gross oxygen production and chlorophyll a. Our study also revealed species-specific traits, including differences in the timing of antioxidant regulation, as well as drastic differences in the production of the sulfur compound dimethylsulfoniopropionate during bleaching. Indeed, the concentration of this antioxidant increased two-fold in A. millepora after the corals started to bleach, while it decreased 70% in S. pistillata. We identify a well-defined cascading response to thermal stress, demarking clear pathophysiological reactions conserved across the two species, which might be central to fully understanding the mechanisms triggering thermally induced coral bleaching. These results highlight that bleaching is a conserved mechanism, but specific adaptations linked to the coral's antioxidant capacity drive differences in the sensitivity and thus tolerance of each coral species to thermal stress.

  10. Long Term Preservation of Earth Observation Data in Europe - Challenge and Cooperation Activities

    Science.gov (United States)

    Molch, K.; Albani, M.

    2014-12-01

    Earth observation data are unique snapshots of the Earth and the atmosphere. As such they constitute a humankind asset in their importance for monitoring changes in global environmental conditions. With spaceborne Earth observation (EO) missions dating back to the 1970s, 40 years worth of observations are now available in EO data archives worldwide. Data holdings are growing exponentially, e.g. with the Sentinel series of high resolution EO satellites of the European Copernicus Program - which introduces a new dimension of data volumes to be handled. As other EO data holders around the globe, the European Space Agency (ESA) and its member states are committed to keeping the valuable EO data assets safe, accessible, and useable for an unlimited timespan. Rapidly evolving information technology and changing user requirements call for a dedicated and coordinated approach to EO data long term preservation. In Europe collaborative EO data stewardship activities are coordinated by ESA within the ESA long term data preservation (LTDP) program. With a view to the entire data set life cycle of historic and current missions an active LTDP working group addresses a wide range of relevant technical and organizational topics. Studies investigate archiving and access technologies, user expectations, or applicable standards; guidelines and best practices recommend preservation workflows, steps to take in curating individual data sets, the composition of the preserved data set, or concepts for introducing persistent identifiers. Fostering an active international exchange, the activities and documents developed within this European LTDP framework extend beyond Europe by being introduced to the Group on Earth Observations (GEO) and the Committee on Earth Observation Satellites (CEOS). The paper describes the European LTDP cooperation framework, discusses individual focus areas and current activities, and highlights the interaction with global data stewardship initiatives.

  11. Activation analysis of rare-earth elements in opium and cannabis samples

    International Nuclear Information System (INIS)

    Henke, G.

    1977-01-01

    Rare-earth concentrations in 65 Opium, Cannabis and Cannabis resin samples seized from various parts of the world were determined by destructive NAA. Because of the greater concentrations of Ca, P, K, Fe, Na and Si in plant materials, rare-earth elements were isolated after neutron irradiation and determined by gamma-spectrometry. The main steps of the method are: Preashing of 1 g Cannabis resin, 2.5 g Cannabis or 7.5 g Opium, respectively, in quartz ampoules (5 h, 500 deg C). Neutron irradiation, 24 h at 5x10 13 n cm -2 sec -1 . Cooling period 2-3 days. After addition of 0.1 μCi 139 Ce and rare-earth carriers wet ashing of irradiated samples with H 2 SO 4 /HNO 3 , followed by alternate addition of HNO 3 and H 2 O 2 (30%). Precipitation and removal of silicates, precipitation of fluorides, precipitation of hydroxides. Dissolution of hydroxides in HCl. Extraction with di-(2-ethylhexyl)phosphate (DEHP)/toluene and twice back-extraction of rare earths, gamma-spectrometry of HCl phase. Due to sample activity and half-life of nuclides, three measurements were made on each sample: 2 days (for La, Sm, Gd, Ho, Er, Yb); 14 days (for Nd, Lu) and 30 days after irradiation (for Ce, Eu, Tb). Great variations in absolute element concentrations, but only small significant differences of rare earth concentration ratios were found, indicating inconsiderable biogeochemical fractionation. The mean values of these ratios correspond to the relative abundances of the rare earths in the upper continental earth's crust. (T.G.)

  12. 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

    2015-11-01

    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.

  13. Sodium Hydroxide and Calcium Hydroxide Hybrid Oxygen Bleaching with System

    Science.gov (United States)

    Doelle, K.; Bajrami, B.

    2018-01-01

    This study investigates the replacement of sodium hydroxide in the oxygen bleaching stage using a hybrid system consisting of sodium hydroxide calcium hydroxide. Commercial Kraft pulping was studied using yellow pine Kraft pulp obtained from a company in the US. The impact of sodium hydroxide, calcium hydroxide hybrid system in regard to concentration, reaction time and temperature for Kraft pulp was evaluated. The sodium hydroxide and calcium hydroxide dosage was varied between 0% and 15% based on oven dry fiber content. The bleaching reaction time was varied between 0 and 180 minutes whereas the bleaching temperature ranged between 70 °C and 110 °C. The ability to bleach pulp was measured by determining the Kappa number. Optimum bleaching results for the hybrid system were achieved with 4% sodium hydroxide and 2% calcium hydroxide content. Beyond this, the ability to bleach pulp decreased.

  14. 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.

  15. Levels of enamel erosion for the application of bleaching agents

    OpenAIRE

    Díaz Soriano, Ana; Departamento Académico de Estomatología Biosocial.; Pérez Vargas, Luis; Departamento Academico de Estomatología Biosocial.; Mattos Vela, Manuel; Departamento Academico de Estomatología Biosocial.; Asurza Ruiz, José; Instituto Nacional de Enfermedades Neoplásicas - INEN.; Bernuy Torres, Luis

    2014-01-01

    Dental bleaching systems and its use of toothpaste with bleaching agents lead to search the effect of these systems on the enamel surface. Scientific evidence shows that these systems can provoke an answer in chemical shucture of the dental enamel with loss of calcium . The concentration of calcium was measured in ppm in 27 crowns of human bicuspids. The enamel erosion was measured through the liberation of calcium salts into teeth in two kinds of bleaching toothpastes : Crest whitening and C...

  16. Coral mass bleaching and reef temperatures at Navassa Island, 2006

    Science.gov (United States)

    Miller, M. W.; Piniak, G. A.; Williams, D. E.

    2011-01-01

    Bleaching and associated mortality is an extreme threat to the persistence of coral populations in the projected warming regime of the next few decades. Recent evidence indicates that thermal bleaching thresholds may be affected by water quality gradients. The unexpected encounter of a coral mass bleaching event at a remote, uninhabited Caribbean island (Navassa) during a routine reef assessment cruise in November 2006 provided the opportunity to characterize bleaching responses and thermal exposure in an oceanic area with negligible continental influence or human impact on water quality. The coral taxa most susceptible to bleaching were Agaricia spp. and Montastraea faveolata. Siderastraea siderea, Diploria spp. and Porites porites were intermediately affected, while Porites astreoides and Montastraea cavernosa were minimally affected and negligible bleaching was observed in Acropora palmata. Bleaching prevalence (colonies > 4 cm diameter) ranged from 0.16 to 0.63 among sites. Deeper sites (between 18 and 37 m) had significantly higher prevalence of bleaching than shallow sites (<10 m). This general pattern of more bleaching in deeper sites also occurred within species. Though exposure to high-temperature stress was not greater at deeper sites, water motion, which may bolster bleaching resistance, was likely less. In situ loggers indicated temperatures over 30 °C initiated at shallow sites in mid-August, at deeper sites in early September, and were persistent at all sites until mid-October. Long term (1983-2007) climatologies constructed from AVHRR SSTs suggest that the mass bleaching event observed at Navassa in 2006 corresponded with greater intensity and duration of warm temperature anomalies than occurred in 2005, for which no in situ observations (bleaching nor temperature) are available.

  17. Effects of a New Bleaching Gel on Tooth Whitening

    Science.gov (United States)

    2016-05-17

    include ease of application, reduced chair time and cost, high success rate, and safety of materials.6 Furthermore, bleaching teeth with 10... dental workhorse for over 70 years.4 HP’s bleaching success is attributed to its ability to penetrate tooth structure and produce free radicals that...home whitening. Due to the prevalence of HP and CP in many bleaching products, the dental literature is saturated with research on their respective

  18. 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

    the likely significance of the difficult-to-bleach residual feldspar signals in non-aeolian samples. For a set of mainly Late Pleistocene non-aeolian sediments, large aliquot quartz doses are then used to predict feldspar doses (based on a knowledge of the sample dose rates). The differences between observed...... 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...

  19. 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.

  20. 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.

  1. Arundo donax L. reed: new perspectives for pulping and bleaching. Part 4. Peroxide bleaching of organosolv pulps.

    Science.gov (United States)

    Shatalov, A A; Pereira, H

    2005-05-01

    A comparative study on TCF (totally chlorine-free) bleachability of organosolv pulps from the annual fibre crop Arundo donax L. (giant reed) was carried out using a simple three-stage peroxide bleaching sequence without oxygen pre-bleaching. ASAM (alkali-sulfite-anthraquinone-methanol), Organocell (alkali-anthraquinone-methanol) and ethanol-soda organosolv pulps were bleached and compared with kraft pulp, as a reference. The final brightness of 76-78% ISO was attained for all tested pulps. The chemical charge required to reach this level of brightness varied for different pulps (despite the equal initial content of the residual lignin) and directly related to starting brightness values. No direct correlation between brightness improvement and lignin removal during bleaching was found, indicating the influence of the specific pulp properties introduced by pulping process on bleaching chemistry. The general higher bleaching response of organosolv pulps from A. donax was noted in comparison with kraft.

  2. Geology for youth in Lithuania: International Year of Planet Earth-related and other activities

    Science.gov (United States)

    Skridlaite, Grazina; Guobyte, Rimante; Skrinskas, Skirmantas; Nemaniene, Jurgita

    2010-05-01

    A great number of Lithuanian secondary and high schools devoted a range of activities to Earth sciences on September 22 (autumn equinox), 2008 proclaimed by the Lithuanian National Committee for IYPE and Ministry of Education and Science of Lithuania as "Earth's day". Beforehand, the 11 IYPE brochures were translated, supplemented with relevant Lithuanian data and placed on the website www.zemesmetai.lt. The activities comprised lessons, competitions, performances, field trips, seminars, excursions to museums and nature sites, meetings with geologists and naturalists etc. In many schools the 10 scientific themes were expanded, transformed and included into different school programmes such as geography, chemistry, physics, biology, Lithuanian language etc. The other schools preferred to organise discussions, performances and concerts where children expressed their concern about future of the Earth and suggested ways to save it. Several schools invited geologists, ecologists or other representatives of Earth sciences or local authorities to provide with information on environmental and geological issues in Lithuania and their own surroundings. Several museums and nature sites were visited. The "Earth's day" was advertised and broadcasted on TV and radio, reflected in the press. The reports from schools were placed on the Lithuanian IYPE website. The Board acknowledged the best participants with special letter of thanks. It turned out that despite the provided information on different subjects of geology only few of them were chosen. School teachers encountered some problems relating the Earth's interior with its surface, recognising modern geological processes etc. They found some brochures to be too complicated for non-specialists. Biodiversity was much easier to explain and present as geodiversity. Nevertheless, everybody admitted the great importance of geosciences in society and insufficient knowledge, and greatly acknowledged the initiative of the IYPE. The

  3. The influence of bleaching agent and temperature on bleaching efficacy and volatile components of fluid whey and whey retentate.

    Science.gov (United States)

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

    2013-10-01

    Fluid whey or retentate are often bleached to remove residual annatto Cheddar cheese colorant, and this process causes off-flavors in dried whey proteins. This study determined the impact of temperature and bleaching agent on bleaching efficacy and volatile components in fluid whey and fluid whey retentate. Freshly manufactured liquid whey (6.7% solids) or concentrated whey protein (retentate) (12% solids, 80% protein) were bleached using benzoyl peroxide (BP) at 100 mg/kg (w/w) or hydrogen peroxide (HP) at 250 mg/kg (w/w) at 5 °C for 16 h or 50 °CC for 1 h. Unbleached controls were subjected to a similar temperature profile. The experiment was replicated three times. Annatto destruction (bleaching efficacy) among treatments was compared, and volatile compounds were extracted and separated using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS). Bleaching efficacy of BP was higher than HP (P 0.05). Retentate bleached with HP at either temperature had higher relative abundances of pentanal, hexanal, heptanal, and octanal than BP bleached retentate (P < 0.05). Liquid wheys generally had lower concentrations of selected volatiles compared to retentates. These results suggest that the highest bleaching efficacy (within the parameters evaluated) in liquid whey is achieved using BP at 5 or 50 °C and at 50 °C with HP or BP in whey protein retentate. © 2013 Institute of Food Technologists®

  4. 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.

  5. Penetration of hydrogen peroxide and degradation rate of different bleaching products.

    Science.gov (United States)

    Marson, F C; Gonçalves, R S; Silva, C O; Cintra, L T Â; Pascotto, R C; Santos, P H Dos; Briso, A L F

    2015-01-01

    This study's aim was to evaluate the degradation rate of hydrogen peroxide (H2O2) and to quantify its penetration in tooth structure, considering the residence time of bleaching products on the dental enamel. For this study, bovine teeth were randomly divided according to the bleaching product received: Opalescence Xtra Boost 38%, White Gold Office 35%, Whiteness HP Blue 35%, Whiteness HP Maxx 35%, and Lase Peroxide Sensy 35%. To analyze the degradation of H2O2, the titration of bleaching agents with potassium permanganate was used, while the penetration of H2O2 was measured via spectrophotometric analysis of the acetate buffer solution, collected from the artificial pulp chamber. The analyses were performed immediately as well as 15 minutes, 30 minutes, and 45 minutes after product application. The data of degradation rate of H2O2 were submitted to analysis of variance (ANOVA) and Tukey tests, while ANOVA and Fisher tests were used for the quantification of H2O2, at the 5% level. The results showed that all products significantly reduced the concentration of H2O2 activates at the end of 45 minutes. It was also verified that the penetration of H2O2 was enhanced by increasing the residence time of the product on the tooth surface. It was concluded that the bleaching gels retained substantial concentrations of H2O2 after 45 minutes of application, and penetration of H2O2 in the dental structure is time-dependent.

  6. Atmosphere Kits: Hands-On Learning Activities with a Foundation in NASA Earth Science Missions.

    Science.gov (United States)

    Teige, V.; McCrea, S.; Damadeo, K.; Taylor, J.; Lewis, P. M., Jr.; Chambers, L. H.

    2016-12-01

    The Science Directorate (SD) at NASA Langley Research Center provides many opportunities to involve students, faculty, researchers, and the citizen science community in real world science. The SD Education Team collaborates with the education community to bring authentic Earth science practices and real-world data into the classroom, provide the public with unique NASA experiences, engaging activities, and advanced technology, and provide products developed and reviewed by science and education experts. Our goals include inspiring the next generation of Science, Technology, Engineering and Mathematics (STEM) professionals and improving STEM literacy by providing innovative participation pathways for educators, students, and the public. The SD Education Team has developed Atmosphere activity kits featuring cloud and aerosol learning activities with a foundation in NASA Earth Science Missions, the Next Generation Science Standards, and The GLOBE Program's Elementary Storybooks. Through cloud kit activities, students will learn how to make estimates from observations and how to categorize and classify specific cloud properties, including cloud height, cloud cover, and basic cloud types. The purpose of the aerosol kit is to introduce students to aerosols and how they can affect the colors we see in the sky. Students will engage in active observation and reporting, explore properties of light, and model the effects of changing amounts/sizes or aerosols on sky color and visibility. Learning activity extensions include participation in ground data collection of environmental conditions and comparison and analysis to related NASA data sets, including but not limited to CERES, CALIPSO, CloudSat, and SAGE III on ISS. This presentation will provide an overview of multiple K-6 NASA Earth Science hands-on activities and free resources will be available.

  7. International Year of Planet Earth - Accomplishments, Activities, Challenges and Plans in Mexico

    Science.gov (United States)

    Fucugauchi, J. U.; Perez-Cruz, L. L.; Alaniz-Alvarez, S.

    2009-12-01

    The International Year of Planet Earth started as a joint initiative by UNESCO and IUGS with the participation of several geosciences organizations, and developed into a major international geosciences program for the triennium 2007-2009, with the inclusion and participation of national and regional committees. In this presentation we focus on current activities and plans in our country and the participation in international activities. Mexican community has been part of international programs since the International Geophysical Year, continuing through its participation in other programs, e.g., Upper Mantle, Geodynamics, Lithosphere, IHY, IPY and eGY. IYPE activities have concentrated in publications, OneGeology, radio/TV programs, organization of conferences, meetings and outreach events. A book series on Earth Science Experiments for Children has been edited, with first books published on “Atmospheric Pressure and Free Fall of Objects”, “Light and Colors”, “Standing on Archimedes”, “Foucault and Climate” and “Earth and its Waves “. Books are distributed to schools, with tens of thousand copies distributed nationwide and new editions underway. Other publications include leaflets, books and special El Faro issues (edited by the National University) and articles in other journals. In 2007 the AGU Joint Assembly with international participation from US, Canada, Europe and Latin America was held in Acapulco. Current plans include an electronic open-access journal, additional publications of the Planet Earth series, articles and special issues in journals and magazines, plus events on selected themes from the IYPE science program, particularly on Megacities, Hazards, Resources and Biodiversity. Mexico City metropolitan area, with > 22 million inhabitants presents special challenges, being at high altitude within an active tectonic and volcanic area requiring major efforts in water supply, water control, rains and waste disposal and management

  8. Mechanisms of Earth activity forsed by external celestial bodies:energy budjet and nature of cyclicity

    Science.gov (United States)

    Barkin, Yu. V.; Ferrandiz, J. M.

    2003-04-01

    In given report we discuss tidal and non-tidal mechanisms of forced tectonic (endogenous) activity of the Earth caused by gravitational attraction of the Moon, Sun and the planets. On the base of the classical solution of the problem of elasticity for model of the Earth with concentric mass distribution the evaluations of the tidal energy and power of Earth lunar-solar deformations, including their joint effect, were obtained. Important role of the joint energetic effect of rotational deformation of the Earth with lunar and solar tides was illustrated. Gravitational interaction of the Moon and Sun with non-spherical, non-homogeneous shells of the Earth generates big additional mechanical forces and moments of the interaction of the neighboring shells (rigid core, liquid core, mantle, lithosphere and separate plates). Acting of these forces and moments in the different time scales on the corresponding sells generates cyclic perturbations of the tensional state of the shells, their deformations, small relative translational displacements and small relative rotational oscillations of the shells. In geological period of time it leads to a fundamental tectonic reconstruction of the Earth. These additional forces and moments of the cyclic celestial-mechanical nature produce cyclic deformations of the all layers of the body and organize and control practically all natural processes. The additional force between mantle and core is cyclic and characterized by the wide basis of frequencies typical for orbital motions (of the Sun, Moon and planets), for rotational motion of the Earth, Moon and Sun and for many from observed natural processes. The problem about small relative translatory-rotary motion of the two shells separated by the thin viscous-elastic layer is studied. The differential equations of motion were obtained and have been studied in particular cases (plane motion of system; case of two axisymmetrical interacting shells and oth.) by approximate methods of small

  9. Does deposition depth control the OSL bleaching of fluvial sediment?

    NARCIS (Netherlands)

    Cunningham, A. C.; Wallinga, J.; Hobo, N.; Versendaal, A. J.; Makaske, B.; Middelkoop, H.

    2014-01-01

    The Optically Stimulated Luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  10. 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.…

  11. The evaluation of hydrogen peroxide bleaching of Gonometa ...

    African Journals Online (AJOL)

    The effect of hydrogen peroxide bleaching on Gonometa postica silk and the influence that temperature, pH and time duration had on hydrogen peroxide release , colour change, breaking load and stiffness were determined. The best bleaching (81 delta E) of the Gonometa postica silk fabric was obtained with 60 minutes ...

  12. The bleaching syndrome: manifestation of a post-colonial pathology ...

    African Journals Online (AJOL)

    The post-colonial root of African problems is directly related to skin color. Under the cloak of personal preference, light skin among African women has replaced dark skin as the native ideal. The aftermath is manifestation of the Bleaching Syndrome. Social Work professionals have overlooked the Bleaching Syndrome as ...

  13. Anolyte as an alternative bleach for stained cotton fabrics ...

    African Journals Online (AJOL)

    ... as the two- and three-factor interactions. The results from the study indicated that Anolyte was less effective than sodium hypochlorite as a stain remover for blood, tea, soot/mineral oil and blackcurrant juice. It was noted that the temperature of bleach liquids had an influence on the removal of stains by both bleach liquids.

  14. Color Recovery Effect of Different Bleaching Systems on a ...

    African Journals Online (AJOL)

    Background and Purpose: Discoloration of resin‑based composites is a commonly encountered problem, and bleaching agents may be used for the therapy of the existing discoloration. The purpose of this study was to investigate in vitro color recovery effect of different bleaching systems on the heavily discolored composite ...

  15. FT–Raman investigation of bleaching of spruce thermomechanical pulp

    Science.gov (United States)

    U.P. Agarwal; L.L. Landucci

    2004-01-01

    Spruce thermomechanical pulp was bleached initially by alkaline hydrogen peroxide and then by sodium dithionite and sodium borohydride. Near-infrared Fourier-transform–Raman spectroscopy revealed that spectral differences were due primarily to coniferaldehyde and p-quinone structures in lignin, new direct evidence that bleaching removes p-quinone structures. In...

  16. The Bleaching Syndrome: Manifestation of a Post-Colonial ...

    African Journals Online (AJOL)

    The post-colonial root of African problems is directly related to skin color. Under the cloak of personal preference, light skin among African women has replaced dark skin as the native ideal. The aftermath is manifestation of the Bleaching Syndrome. Guidance and Counselling professionals have overlooked the Bleaching ...

  17. Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef ...

    African Journals Online (AJOL)

    Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef-building Corals, Stylophora pistillata and Platygyra ryukyuensis . ... Symbiodinium ITS2 types exhibit diverse photo-physiological responses to thermal stress, and may partially explain the variable bleaching susceptibilities of some hermatypic coral species.

  18. Alkali and bleach treatment of the extracted cellulose from pineapple ...

    African Journals Online (AJOL)

    We successfully extracted cellulose from pineapple leaves (Ananas comosus) using alkali treatment and bleaching. Alkali treatment was done using aqueous sodium hydroxide while bleaching was done using acetate buffer and aqueous sodium chlorite. The extracted cellulose was characterized using Scanning electron ...

  19. Color Recovery Effect of Different Bleaching Systems on a ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Odontology 2016;104:305-9. 29. Joiner A. The bleaching of teeth: A review of the literature. J Dent 2006;34:412-9. 30. Haywood VB, Heymann HO. Nightguard vital bleaching: How safe is it? Quintessence Int 1991;22:515-23. 31. Fay RM, Servos T, Powers JM. Color of restorative materials after staining and ...

  20. Energy deposition in the earth's atmosphere due to impact of solar activity-generated disturbances

    Science.gov (United States)

    Wu, S. T.; Kan, L. C.; Tandberg-Hanssen, E.; Dryer, M.

    1979-01-01

    Energy deposition in and dynamic responses of the terrestrial atmosphere to solar flare-generated shocks and other physical processes - such as particle precipitation and local heating - are investigated self-consistently in the context of hydrodynamics, the problem being treated as an initial boundary-value problem. It is extremely difficult to construct a general model for the line solar activity-magnetosphere-atmosphere; however, a limited model for this link is possible. The paper describes such a model, and presents some results on energy deposition into the earth's atmosphere due to solar activity-generated disturbances. Results from the present calculations are presented and discussed.

  1. Neutron activation analysis of rare earths and some other elements in material of geochemical interest

    International Nuclear Information System (INIS)

    Brunfelt, A.O.

    1975-01-01

    ngle-element methods for the determination by neutron activation analysis of antimony, chromium, phosphorus, selenium and silver in international geochemical standard rocks, and the determination of rare earth elements i in standard rocks and apatites are described and discussed in twelve previously published papers, and in an eighteen page summary. Chemical separationtechniques are also discussed and the results are compared with previously obtained results with the same standard rocks. The accuracy of neutron activation analysis is discussed in comparison with isotope dilution mass spectroscopy, atomic absorption, gas chromatography and spark source mass spectrometry. (JIW)

  2. Finite Element Limit Analysis of Active Earth Pressure in Nonhomogeneous soils

    Directory of Open Access Journals (Sweden)

    Peyman Hamidi

    2016-01-01

    Full Text Available Limit analysis is a useful method to calc1ulate bearing capacity of footings, earth pressure of retaining walls, stability of slopes and excavations. In recent years, many efforts have been focused on stability problems of geotechnical structures with the limit analysis method. The limit analysis method includes the upper and lower bound theorems. By using the two theorems, the range, in which the true solution falls, can be found. In this paper upper bound finite element limit analysis is used for calculate active earth force on retaining walls in non-homogeneous soils. Elements with linear strain rates cause to eliminate the necessity of velocity discontinuities between the elements. Nonlinear programming based on second order cone programming (SOCP ,which has good conformity with Mohr-Coulomb criterion used in this paper. The sensitivity of active earth force against backfill surcharge (q, soil layers cohesion (Ci, soil layers unit weight (γi and friction angle between soil and wall (δi is surveyed.

  3. Laser Teeth Bleaching: Evaluation of Eventual Side Effects on Enamel and the Pulp and the Efficiency In Vitro and In Vivo

    Science.gov (United States)

    De Moor, Roeland Jozef Gentil; Meire, Maarten August; De Coster, Peter Jozef

    2015-01-01

    Light and heat increase the reactivity of hydrogen peroxide. There is no evidence that light activation (power bleaching with high-intensity light) results in a more effective bleaching with a longer lasting effect with high concentrated hydrogen peroxide bleaching gels. Laser light differs from conventional light as it requires a laser-target interaction. The interaction takes place in the first instance in the bleaching gel. The second interaction has to be induced in the tooth, more specifically in the dentine. There is evidence that interaction exists with the bleaching gel: photothermal, photocatalytical, and photochemical interactions are described. The reactivity of the gel is increased by adding photocatalyst of photosensitizers. Direct and effective photobleaching, that is, a direct interaction with the colour molecules in the dentine, however, is only possible with the argon (488 and 415 nm) and KTP laser (532 nm). A number of risks have been described such as heat generation. Nd:YAG and especially high power diode lasers present a risk with intrapulpal temperature elevation up to 22°C. Hypersensitivity is regularly encountered, being it of temporary occurrence except for a number of diode wavelengths and the Nd:YAG. The tooth surface remains intact after laser bleaching. At present, KTP laser is the most efficient dental bleaching wavelength. PMID:25874258

  4. Effects of bleaching agents on surface roughness of filling materials.

    Science.gov (United States)

    Markovic, Ljubisa; Jordan, Rainer Andreas; Glasser, Marie-Claire; Arnold, Wolfgang Hermann; Nebel, Jan; Tillmann, Wolfgang; Ostermann, Thomas; Zimmer, Stefan

    2014-01-01

    The aim of this study was to use a non-tactile optical measurement system to assess the effects of three bleaching agents' concentrations on the surface roughness of dental restoration materials. Two composites (Grandio, Venus) and one glass ionomer cement (Ketac Fil Plus) were used in this in vitro study. Specimens were treated with three different bleaching agents (16% and 22% carbamide peroxide (Polanight) and 38% hydrogen peroxide (Opalescence Boost)). Surface roughness was measured with an optical profilometer (Infinite Focus G3) before and after the bleaching treatment. Surface roughness increased in all tested specimens after bleaching treatment (p<0.05). Our in vitro study showed that dental bleaching agents influenced the surface roughness of different restoration materials, and the restoration material itself was shown to have an impact on alteration susceptibility. There seemed to be no clinical relevance in case of an optimal finish.

  5. Coral bleaching pathways under the control of regional temperature variability

    Science.gov (United States)

    Langlais, C. E.; Lenton, A.; Heron, S. F.; Evenhuis, C.; Sen Gupta, A.; Brown, J. N.; Kuchinke, M.

    2017-11-01

    Increasing sea surface temperatures (SSTs) are predicted to adversely impact coral populations worldwide through increasing thermal bleaching events. Future bleaching is unlikely to be spatially uniform. Therefore, understanding what determines regional differences will be critical for adaptation management. Here, using a cumulative heat stress metric, we show that characteristics of regional SST determine the future bleaching risk patterns. Incorporating observed information on SST variability, in assessing future bleaching risk, provides novel options for management strategies. As a consequence, the known biases in climate model variability and the uncertainties in regional warming rate across climate models are less detrimental than previously thought. We also show that the thresholds used to indicate reef viability can strongly influence a decision on what constitutes a potential refugia. Observing and understanding the drivers of regional variability, and the viability limits of coral reefs, is therefore critical for making meaningful projections of coral bleaching risk.

  6. Endonuclease active site plasticity allows DNA cleavage with diverse alkaline Earth and transition metal ions.

    Science.gov (United States)

    Vasu, Kommireddy; Saravanan, Matheshwaran; Nagaraja, Valakunja

    2011-09-16

    A majority of enzymes show a high degree of specificity toward a particular metal ion in their catalytic reaction. However, Type II restriction endonuclease (REase) R.KpnI, which is the first member of the HNH superfamily of REases, exhibits extraordinary diversity in metal ion dependent DNA cleavage. Several alkaline earth and transition group metal ions induce high fidelity and promiscuous cleavage or inhibition depending upon their concentration. The metal ions having different ionic radii and co-ordination geometries readily replace each other from the enzyme's active site, revealing its plasticity. Ability of R.KpnI to cleave DNA with both alkaline earth and transition group metal ions having varied ionic radii could imply utilization of different catalytic site(s). However, mutation of the invariant His residue of the HNH motif caused abolition of the enzyme activity with all of the cofactors, indicating that the enzyme follows a single metal ion catalytic mechanism for DNA cleavage. Indispensability of His in nucleophile activation together with broad cofactor tolerance of the enzyme indicates electrostatic stabilization function of metal ions during catalysis. Nevertheless, a second metal ion is recruited at higher concentrations to either induce promiscuity or inhibit the DNA cleavage. Regulation of the endonuclease activity and fidelity by a second metal ion binding is a unique feature of R.KpnI among REases and HNH nucleases. The active site plasticity of R.KpnI opens up avenues for redesigning cofactor specificities and generation of mutants specific to a particular metal ion.

  7. Determination of rare earth contents in plant and soil by neutron activation analysis (NAA)

    International Nuclear Information System (INIS)

    Krafka, B.; Lin, X.L.; Henkelmann, R.

    1998-01-01

    Full text: The results presented are typical analytical results for Bavarian soils and plants. Plants and soils collected from identical sites are used to quantify the ratios of rare earth contents. This work has been in close cooperation with several governmental institutions, who are responsible for the protection and surveillance of agricultural sites and wooded areas. Routine sampling takes place on selected areas in the federal state of Bavaria, and the samples (soil and plants as wheat, corn or needles) are analysed with use of AAS, ICP-OES or ICP-MS techniques. INAA as an alternative method is in this context very interesting because it does not involve any sample pretreatment, prior to irradiation. It could be shown for chosen elements (K, Cr, Zn etc.), that incomplete digestion can lead to results which are remarkably lower than the total content in the sample. INAA also is an excellent technique to analyse rare earth elements. The advantage of analysing the original material, which only needs to be dried and homogenized, allows the determination of total values for most of the elements, independent of the chemical binding state of the atoms. Due to this reason, INAA is often called 'independent of matrix'. Only when the g-spectroscopy after activation is carried out, the main components may disturb the determination of trace elements. In soils, the matrix allows the pure instrumental determination of 9 rare earth elements (Ce, Dy, Eu, La, Lu, Nd, Sm, Tb, Yb). In plant material, the rare earth concentrations are much lower, so a chemical separation is needed in order to remove or reduce the main interferences like Na, K, Br etc. This combination of NAA with radiochemical separation is called Radiochemical Neutron Activation Analysis (RNAA) and allows to determine the same elements as in soils, except Dy

  8. EarthScope Transportable Array Siting Outreach Activities in Alaska and Western Canada

    Science.gov (United States)

    Gardine, L.; Dorr, P. M.; Tape, C.; McQuillan, P.; Taber, J.; West, M. E.; Busby, R. W.

    2014-12-01

    The EarthScopeTransportable Array is working to locate over 260 stations in Alaska and western Canada. In this region, new tactics and partnerships are needed to increase outreach exposure. IRIS and EarthScope are partnering with the Alaska Earthquake Center, part of University of Alaska Geophysical Institute, to spread awareness of Alaska earthquakes and the benefits of the Transportable Array for Alaskans. Nearly all parts of Alaska are tectonically active. The tectonic and seismic variability of Alaska requires focused attention at the regional level, and the remoteness and inaccessibility of most Alaska villages and towns often makes frequent visits difficult. For this reason, Alaska outreach most often occurs at community events. When a community is accessible, every opportunity to engage the residents is made. Booths at state fairs and large cultural gatherings, such as the annual convention of the Alaska Federation of Natives, are excellent venues to distribute earthquake information and to demonstrate a wide variety of educational products and web-based applications related to seismology and the Transportable Array that residents can use in their own communities. Region-specific publications have been developed to tie in a sense of place for residents of Alaska. The Alaska content for IRIS's Active Earth Monitor will emphasize the widespread tectonic and seismic features and offer not just Alaska residents, but anyone interested in Alaska, a glimpse into what is going on beneath their feet. The concerted efforts of the outreach team will have lasting effects on Alaskan understanding of the seismic hazard and tectonics of the region. Efforts to publicize the presence of the Transportable Array in Alaska, western Canada, and the Lower 48 also continue. There have been recent articles published in university, local and regional newspapers; stories appearing in national and international print and broadcast media; and documentaries produced by some of the world

  9. Examples of learning activities for Earth and Space Sciences in the new Italian National curriculum

    Science.gov (United States)

    Macario, Maddalena

    2016-04-01

    In the last few years, starting from 2010, science curricula were changed dramatically in the secondary Italian school as consequence of a radical law reform. In particular, Earth Science and Astronomy subjects have been shifted from the last to the previous school years; in addition, these subjects have been integrated with other natural sciences learning, such as biology and chemistry. As a consequence, Italian teachers felt forced to totally revise their teaching methods for all of these disciplines. The most demanding need was adapting content to younger learners, as those of the first years are, who usually do have neither pre-knowledge in physics nor high level maths skills. Secondly, content learning was progressively driven toward a greater attention to environmental issues in order to raise more awareness in learners about global changes as examples of fragile equilibrium of our planet. In this work some examples of activities are shown, to introduce students to some astronomical phenomena in a simpler way, which play a key role in influencing other Earth's events, in order to make pupils more conscious about how and to what extent our planet depends on space, at different time scales. The activities range from moon motions affecting tides, to secondary Earth motions, which are responsible for climate changes, to the possibility to find life forms in other parts of the Universe, to the possibility for humans to live in the space for future space missions. Students are involved in hands-on inquiry-based laboratories that scaffold both theoretic knowledge and practical skills for a deeper understanding of cause-effect relationships existing in the Earth.

  10. 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

  11. Bleaching of reef coelenterates in the San Blas Islands, Panama

    Science.gov (United States)

    Lasker, Howard R.; Peters, Esther C.; Coffroth, Mary Alice

    1984-12-01

    Starting in June 1983, 25 species of hermatypic corals, gorgonians, hydrocorals, anemones and zoanthids in the San Blas Islands, Panama, began showing signs of a loss of colour leading in some cases to a white “bleached” appearance. Histologic examination of six coral species indicated that bleaching was associated with drastic reductions in the density of zooxanthellae and with the atrophy and necrosis of the animal tissue. The severity of the bleaching varied among species and many species were unaffected. The species most extensively affected were: Agaricia spp., which became completely bleached and frequently died; Montastraea annularis which bleached and continued to survive; and Millepora spp. which bleached white but quickly regained their colouration. Shallow reefs dominated by Agaricia spp. suffered the most extensive bleaching. At one site, Pico Feo, 99% of the Agaricia (32% of the living cover) was bleached. On fore reers, which were dominated by Agaricia spp. and M. annularis, the proportion of M. annularis bleached ranged from 18 to 100% and that of Agaricia spp. from 30 to 53%. Transects at Sail Rock and House Reef were surveyed in August 1983 and January 1984. At those sites, 53% of the Agaricia cover died between August and January. The remaining living cover of Agaricia and of all other species exhibited normal colouration in January. Salinity and temperature were monitored every second day at 4 m depth between May 10 and August 28, 1983 at one of the localities. Bleaching was first observed within two weeks of a 2 °C rise in temperature which occurred in late May 1983. Temperatures remained at or above 31.5 °C for the following 3 weeks and were at or above 30 °C for an additional 4 weeks. The bleaching of corals in the San Blas was most likely due to those elevanted temperatures.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Satellite and earth science data management activities at the U.S. geological survey's EROS data center

    Science.gov (United States)

    Carneggie, David M.; Metz, Gary G.; Draeger, William C.; Thompson, Ralph J.

    1991-01-01

    The U.S. Geological Survey's Earth Resources Observation Systems (EROS) Data Center, the national archive for Landsat data, has 20 years of experience in acquiring, archiving, processing, and distributing Landsat and earth science data. The Center is expanding its satellite and earth science data management activities to support the U.S. Global Change Research Program and the National Aeronautics and Space Administration (NASA) Earth Observing System Program. The Center's current and future data management activities focus on land data and include: satellite and earth science data set acquisition, development and archiving; data set preservation, maintenance and conversion to more durable and accessible archive medium; development of an advanced Land Data Information System; development of enhanced data packaging and distribution mechanisms; and data processing, reprocessing, and product generation systems.

  14. Bleach boosting effect of xylanase A from Bacillus halodurans C-125 in ECF bleaching of wheat straw pulp.

    Science.gov (United States)

    Lin, Xiao-qiong; Han, Shuang-yan; Zhang, Na; Hu, Hui; Zheng, Sui-ping; Ye, Yan-rui; Lin, Ying

    2013-02-05

    Past studies have revealed major difficulties in applications of xylanase in the pulp and paper industry as enzymes isolated from many different species could not tolerate high temperatures or highly alkaline conditions. The thermostable xylanase A from Bacillus halodurans C-125 (C-125 xylanase A) was successfully cloned and expressed in Pichia pastoris with a yield as high as 3361 U/mL in a 2 L reactor. Its thermophilic and basophilic properties (optimal activity at 70 °C and pH 9.0), together with the fact it is cellulase-free, render this enzyme attractive for compatible applications in the pulp and paper industry. The pretreatment of wheat straw pulp with C-125 xylanase A at pH 9.0 and 70 °C for 90 min induced the release of both chromophores (Ab(237), Ab(254), Ab(280)) and hydrophobic compounds (Ab(465)) into the filtrate as well as sugar degradation. Moreover, the addition of 10 U xylanase to 1 g wheat straw pulp (dry weight) as pretreatment improved brightness by 5.2% ISO and decreased the kappa number by 5.0% when followed by hydrogen peroxide bleaching. In addition, compared with two commercial enzymes, Pulpzyme HC and AU-PE89, which are normally incorporated in ECF bleaching of wheat straw pulp, C-125 xylanase A proved to be more effective in enhancing brightness as well as preserving paper strength properties. When evaluating the physical properties of pulp samples, such as tensile index, tearing index, bursting index, and post-color (PC) number, the enzymes involved in pretreating pulps exhibited better or the same performances as chemical treatment. Compared with chemical bleaching, chlorine consumption can be significantly reduced by 10% for xylanase-pretreated wheat straw pulp while maintaining the brightness together with the kappa number at the same level. Scanning electron microscopy revealed significant surface modification of enzyme-pretreated pulp fibers with no marked fiber disruptions. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. EarthScope Transportable Array Siting Outreach Activities in Alaska and Western Canada

    Science.gov (United States)

    Dorr, P. M.; Gardine, L.; Tape, C.; McQuillan, P.; Cubley, J. F.; Samolczyk, M. A.; Taber, J.; West, M. E.; Busby, R.

    2015-12-01

    The EarthScope Transportable Array is deploying about 260 stations in Alaska and western Canada. IRIS and EarthScope are partnering with the Alaska Earthquake Center, part of the University of Alaska's Geophysical Institute, and Yukon College to spread awareness of earthquakes in Alaska and western Canada and the benefits of the Transportable Array for people living in these regions. We provide an update of ongoing education and outreach activities in Alaska and Canada as well as continued efforts to publicize the Transportable Array in the Lower 48. Nearly all parts of Alaska and portions of western Canada are tectonically active. The tectonic and seismic variability of Alaska, in particular, requires focused attention at the regional level, and the remoteness and inaccessibility of most Alaskan and western Canadian villages and towns often makes frequent visits difficult. When a community is accessible, every opportunity to engage the residents is made. Booths at state fairs and large cultural gatherings, such as the annual convention of the Alaska Federation of Natives, are excellent venues to distribute earthquake information and to demonstrate a wide variety of educational products and web-based applications related to seismology and the Transportable Array that residents can use in their own communities. Meetings and interviews with Alaska Native Elders and tribal councils discussing past earthquakes has led to a better understanding of how Alaskans view and understand earthquakes. Region-specific publications have been developed to tie in a sense of place for residents of Alaska and the Yukon. The Alaska content for IRIS's Active Earth Monitor emphasizes the widespread tectonic and seismic features and offers not just Alaska residents, but anyone interested in Alaska, a glimpse into what is going on beneath their feet. The concerted efforts of the outreach team will have lasting effects on Alaskan and Canadian understanding of the seismic hazard and

  16. Stewardship of NASA's Earth Science Data and Ensuring Long-Term Active Archives

    Science.gov (United States)

    Ramapriyan, H.; Behnke, J.

    2016-12-01

    NASA's Earth Observing System Data and Information System (EOSDIS) has been in operation since 1994. EOSDIS manages data from pre-EOS missions dating back to 1960s, EOS missions that started in 1997, and missions from the post-EOS era. Its data holdings come from many different sources - satellite and airborne instruments, in situ measures, field experiments, science investigations, etc. Since the beginning of the EOS Program, NASA has followed an open data policy, with non-discriminatory access to data with no period of exclusive access. NASA has well-established processes for assigning and/or accepting datasets into one of 12 Distributed Active Archive Centers (DAACs) that are parts of EOSDIS. EOSDIS has been evolving through several information technology cycles, adapting to hardware and software changes in the commercial sector. NASA is responsible for maintaining Earth science data as long as users are interested in using them for research and applications, which is well beyond the life of the data gathering missions. For science data to remain useful over long periods of time, steps must be taken to preserve: 1. Data bits with no corruption, 2. Discoverability and access, 3. Readability, 4. Understandability, 5. Usability and 6. Reproducibility of results. NASA's Earth Science data and Information System (ESDIS) Project, along with the 12 EOSDIS Distributed Active Archive Centers (DAACs), has made significant progress in each of these areas over the last decade, and continues to evolve its active archive capabilities. Particular attention is being paid in recent years to ensure that the datasets are "published" in an easily accessible and citable manner through a unified metadata model, a common metadata repository (CMR), a coherent view through the earthdata.gov website, and assignment of Digital Object Identifiers (DOI) with well-designed landing/product information pages.

  17. Determination of rare earth elements in rocks by neutron activation analysis with pre-irradiation separation

    International Nuclear Information System (INIS)

    Alcala, A.L.

    1991-01-01

    Rare earth elements were determined by neutron activation analysis in rocks, a group separation before irradiation was developed. The international reference standards AGV-1, BE-N and JB-1, as well the Brazilian geological standards BB-1 and GB-1, provided by the Instituto de Geociencias da Universidade Federal da Bahia, were analysed. The method was based on acid digestion of the samples, cation exchange separation, and coprecipitation of the REE with calcium oxalate. Interferents like U, Th, Ta and Fe were eliminated. The concentration values of eleven REE's (La, Co, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Yb and Lu) were determined. (author)

  18. "Earth, from inside and outside - school activities based on seismology and astronomy"

    Science.gov (United States)

    Chivarean, Radu

    2016-04-01

    Through a multidisciplinary work that integrates Geography education with the other Earth Sciences, we developed an educational project to raise the students' awareness of seismic hazard and to disseminate good practices of earthquake safety. The Romanian Educational Seismic Network (ROEDUSEIS) project (started in 2012) is developed and implemented in partnership with schools from different Romanian cities, our school being one of these. In each participating school a SEP educational seismometer is installed. It is the first educational initiative in Romania in the field of seismology involving the National Institute for Earth Physics - NIEP as coordinator. The e-learning platform website (http://www.roeduseis.ro) represents a great opportunity for students to use real advanced research instruments and scientific data analysis tools in their everyday school activities and a link to observations of Earth phenomena and Earth science in general. The most important educational objectives are related to: preparing comprehensive educational materials as resources for training students and teachers in the analysis and interpretation of seismological data, experimentation of new technologies in projecting and implementing new didactic activities, professional development and support for teachers and development of science curriculum module. The scientific objective is to introduce in schools the use of scientific instruments like seismometer and experimental methods (seismic data analysis). The educational materials entitled "Earthquakes and their effects" is organized in a guide for teachers accompanied by a booklet for students. The structure of the educational material is divided in theoretical chapters followed by sections with activities and experiments adapted to the level of understanding particular to our students. The ROEDUSEIS e-platform should be considered as a modern method for teaching and learning that integrates and completes the work in classroom. The

  19. Stewardship of NASA's Earth Science Data and Ensuring Long-Term Active Archives

    Science.gov (United States)

    Ramapriyan, Hampapuram K.; Behnke, Jeanne

    2016-01-01

    Program, NASA has followed an open data policy, with non-discriminatory access to data with no period of exclusive access. NASA has well-established processes for assigning and or accepting datasets into one of 12 Distributed Active Archive Centers (DAACs) that are parts of EOSDIS. EOSDIS has been evolving through several information technology cycles, adapting to hardware and software changes in the commercial sector. NASA is responsible for maintaining Earth science data as long as users are interested in using them for research and applications, which is well beyond the life of the data gathering missions. For science data to remain useful over long periods of time, steps must be taken to preserve: (1) Data bits with no corruption, (2) Discoverability and access, (3) Readability, (4) Understandability, (5) Usability' and (6). Reproducibility of results. NASAs Earth Science data and Information System (ESDIS) Project, along with the 12 EOSDIS Distributed Active Archive Centers (DAACs), has made significant progress in each of these areas over the last decade, and continues to evolve its active archive capabilities. Particular attention is being paid in recent years to ensure that the datasets are published in an easily accessible and citable manner through a unified metadata model, a common metadata repository (CMR), a coherent view through the earthdata.gov website, and assignment of Digital Object Identifiers (DOI) with well-designed landing product information pages.

  20. Invited review: Annatto usage and bleaching in dairy foods.

    Science.gov (United States)

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

    2010-09-01

    Annatto is a yellow/orange colorant that is widely used in the food industry, particularly in the dairy industry. Annatto, consisting of the carotenoids bixin and norbixin, is most commonly added to produce orange cheese, such as Cheddar, to achieve a consistent color over seasonal changes. This colorant is not all retained in the cheese, and thus a percentage remains in the whey, which is highly undesirable. As a result, whey is often bleached. Hydrogen peroxide and benzoyl peroxide are the 2 bleaching agents currently approved for bleaching whey in the United States. Recent studies have highlighted the negative effect of bleaching on whey flavor while concurrently there is a dearth of current studies on bleaching conditions and efficacy. Recent international mandates have placed additional concern on the use of benzoyl peroxide as a bleaching agent. This review discusses the advantages, disadvantages, regulatory concerns, flavor implications, and optimal usage conditions of 2 widely used bleaching agents, hydrogen peroxide and benzoyl peroxide, as well as a few alternative methods including lipoxygenase, peroxidase, and lactoperoxidase systems. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  1. Interactive Mapping of the Planets: An Online Activity Using the Google Earth Platform

    Science.gov (United States)

    Osinski, G. R.; Gilbert, A.; Harrison, T. N.; Mader, M. M.; Shankar, B.; Tornabene, L. L.

    2013-12-01

    With funding from the Natural Sciences and Engineering Research Council of Canada's PromoScience program and support from the Department of Earth Sciences at The University of Western Ontario, the Centre for Planetary Science and Exploration (CPSX) has developed a new web-based initiative called Interactive Mapping of the Planets (IMAPS). Additional components include in person school visits to deliver inquiry-based workshops, week-long summer camps, and pre-prepared impact rock lending kits, all framed around the IMAPS activity. IMAPS will is now in beta testing mode and will be demonstrated in this session. The general objective of the online activity is for participants to plan and design a rover mission to Mars based on a given mission goal - e.g., to find evidence for past water flow. The activity begins with participants receiving image-analysis training to learn about the different landforms on Mars and which ones are potentially caused by water flow. They then need to pass a short test to show they can consistently identify Martian landforms. From there, the participants choose a landing site and plan a traverse - utilizing the free Google Earth plug-in - and taking into account factors such as hazards and their sites of interest. A mission control blog will provide updates on the status of their mission and a 'choose your rover' option provides the opportunity to unlock more advanced rovers by collaborating with other scientists and rating their missions. Indeed, evaluation of missions will be done using a crowd-sourcing method. In addition to being fully accessible online, CPSX will also target primary- and secondary-school grades in which astronomy and space science is taught. Teachers in K-12 classrooms will be able to sign-up for the activity ahead of time in order to receive a workshop package, which will guide them on how to use the IMAPS online activity with their class. Teachers will be able to set up groups for their classroom so that they can

  2. Syntheses of new rare earth complexes with carboxymethylated polysaccharides and evaluation of their in vitro antifungal activities.

    Science.gov (United States)

    Sun, Xiaobo; Jin, Xiaozhe; Pan, Wei; Wang, Jinping

    2014-11-26

    In the present paper, La, Eu and Yb were selected to represent light, middle and heavy rare earths to form complexes with polysaccharides through chelating coordination of carboxyl groups, which were added into polysaccharide chains by means of carboxymethylation. Their antifungal activities against plant pathogenic fungi were evaluated using growth rate method. These rare earth complexes exhibited various antifungal activities against the tested fungi, depending on rare earth elements, polysaccharide types and fungal species. Among these three metal elements (i.e. La, Eu and Yb), Yb formed the complexes with the most effective antifungal properties. Furthermore, the results showed that ligands of carboxymethylated polysaccharides played a key role in promoting cytotoxicity of the rare earth complexes. Carboxymethylated Ganoderma applanatum polysaccharide (CGAP) was found to be the most effective ligand to form complexes with antifungal activities, followed by carboxymethylated lentinan (CLNT) and carboxymethylated Momordica charantia polysaccharide (CMCP). Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. The Discovery of Cometary Activity in Near-Earth Asteroid (3552) Don Quixote

    Science.gov (United States)

    Mommert, Michael; Hora, Joseph L.; Harris, Alan W.; Reach, William T.; Emery, Joshua P.; Thomas, Cristina A.; Mueller, Michael; Cruikshank, Dale P.; Trilling, David E.; Delbo, Marco; Smith, Howard A.

    2014-01-01

    The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552) Don Quixote, which has never been reported to show activity. Here we present the discovery of cometary activity in Don Quixote based on thermal-infrared observations made with the Spitzer Space Telescope in its 3.6 and 4.5 μm bands. Our observations clearly show the presence of a coma and a tail in the 4.5 μm but not in the 3.6 μm band, which is consistent with molecular band emission from CO2. Thermal modeling of the combined photometric data on Don Quixote reveals a diameter of 18.4_{-0.4}^{+0.3} km and an albedo of 0.03^{+0.02}_{-0.01}, which confirms Don Quixote to be the third-largest known NEO. We derive an upper limit on the dust production rate of 1.9 kg s-1 and derive a CO2 gas production rate of (1.1 ± 0.1) × 1026 molecules s-1. Spitzer Infrared Spectrograph spectroscopic observations indicate the presence of fine-grained silicates, perhaps pyroxene rich, on the surface of Don Quixote. Our discovery suggests that CO2 can be present in near-Earth space over a long time. The presence of CO2 might also explain that Don Quixote's cometary nature remained hidden for nearly three decades.

  4. The discovery of cometary activity in near-Earth asteroid (3552) Don Quixote

    Energy Technology Data Exchange (ETDEWEB)

    Mommert, Michael; Harris, Alan W. [Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstr. 2, D-12489 Berlin (Germany); Hora, Joseph L.; Smith, Howard A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138-1516 (United States); Reach, William T. [Universities Space Research Association, Stratospheric Observatory for Infrared Astronomy, MS 232-11, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Emery, Joshua P. [Department of Earth and Planetary Sciences, University of Tennessee, 1412 Circle Dr., Knoxville, TN 37996 (United States); Thomas, Cristina A. [NASA Postdoctoral Program Fellow, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); Mueller, Michael [SRON Netherlands Institute for Space Research, Postbus 800, 9700 AV Groningen (Netherlands); Cruikshank, Dale P. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Trilling, David E. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Delbo, Marco [UNS-CNRS-Observatoire de la Cote d' Azur, BP4229, F-06304 Nice Cedex 4 (France)

    2014-01-20

    The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552) Don Quixote, which has never been reported to show activity. Here we present the discovery of cometary activity in Don Quixote based on thermal-infrared observations made with the Spitzer Space Telescope in its 3.6 and 4.5 μm bands. Our observations clearly show the presence of a coma and a tail in the 4.5 μm but not in the 3.6 μm band, which is consistent with molecular band emission from CO{sub 2}. Thermal modeling of the combined photometric data on Don Quixote reveals a diameter of 18.4{sub −0.4}{sup +0.3} km and an albedo of 0.03{sub −0.01}{sup +0.02}, which confirms Don Quixote to be the third-largest known NEO. We derive an upper limit on the dust production rate of 1.9 kg s{sup –1} and derive a CO{sub 2} gas production rate of (1.1 ± 0.1) × 10{sup 26} molecules s{sup –1}. Spitzer Infrared Spectrograph spectroscopic observations indicate the presence of fine-grained silicates, perhaps pyroxene rich, on the surface of Don Quixote. Our discovery suggests that CO{sub 2} can be present in near-Earth space over a long time. The presence of CO{sub 2} might also explain that Don Quixote's cometary nature remained hidden for nearly three decades.

  5. The discovery of cometary activity in near-Earth asteroid (3552) Don Quixote

    International Nuclear Information System (INIS)

    Mommert, Michael; Harris, Alan W.; Hora, Joseph L.; Smith, Howard A.; Reach, William T.; Emery, Joshua P.; Thomas, Cristina A.; Mueller, Michael; Cruikshank, Dale P.; Trilling, David E.; Delbo, Marco

    2014-01-01

    The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552) Don Quixote, which has never been reported to show activity. Here we present the discovery of cometary activity in Don Quixote based on thermal-infrared observations made with the Spitzer Space Telescope in its 3.6 and 4.5 μm bands. Our observations clearly show the presence of a coma and a tail in the 4.5 μm but not in the 3.6 μm band, which is consistent with molecular band emission from CO 2 . Thermal modeling of the combined photometric data on Don Quixote reveals a diameter of 18.4 −0.4 +0.3 km and an albedo of 0.03 −0.01 +0.02 , which confirms Don Quixote to be the third-largest known NEO. We derive an upper limit on the dust production rate of 1.9 kg s –1 and derive a CO 2 gas production rate of (1.1 ± 0.1) × 10 26 molecules s –1 . Spitzer Infrared Spectrograph spectroscopic observations indicate the presence of fine-grained silicates, perhaps pyroxene rich, on the surface of Don Quixote. Our discovery suggests that CO 2 can be present in near-Earth space over a long time. The presence of CO 2 might also explain that Don Quixote's cometary nature remained hidden for nearly three decades.

  6. 'In vitro' assessment to instrumented indentation hardness tests in enamel of bovine teeth, before and after dental bleaching by laser

    International Nuclear Information System (INIS)

    Britto Junior, Francisco Meira

    2004-01-01

    The laser enamel bleaching is a common used procedure due to its satisfactory esthetic results. The possible changes on the dental structures caused by the bleaching technique are of great importance. The enamel superficial microhardness changes through instrumented indentation hardness on bovine teeth were analyzed in this present study. The samples were divided in two halves, one being the control and the other irradiated with a diode laser (808 nm) or with a Nd:YAG laser (1064 nm) to activate the Whiteness HP bleaching gel (hydrogen peroxide at 35%). It was possible to conclude that there was a statistical significant increase on the enamel superficial microhardness (Group I, sample 1 and Group II, sample 1) despite this increase did not seem to indicate a concern regarding the enamel surface resistance change. There was not a significant statistical change on the enamel microhardness on the other samples. The final conclusion is that there was no superficial enamel morphological change after these treatments. (author)

  7. 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...... alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, their observation potentially allows for a significant simplification of optofluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip microfluidic...

  8. High sucrolytic activity by invertase immobilized onto magnetic diatomaceous earth nanoparticles

    Directory of Open Access Journals (Sweden)

    Mariana P. Cabrera

    2017-03-01

    Full Text Available Invertase immobilized on magnetic diatomaceous earth nanoparticles (mDE-APTES-invertase with high sucrolytic activity was obtained by an easy and low-cost method. An experimental design was carried out to investigate the best immobilization conditions and it allowed obtaining an immobilized derivative with a residual specific activity equal to 92.5%. Then, a second experimental design selected the mDE-APTES-invertase with higher specific activity in relation to other derivatives reported in the literature (2.42-fold. Thermal and storage stability for immobilized invertase were found to be 35 °C for 60 min (85% retained activity and 120 days storage period (80% retained activity, respectively. Besides, a residual activity higher than 60% and 50% were observed for mDE-APTES-invertase after reuse in short and long term, respectively. Given the simple and efficient method to obtain an immobilized derivative with high activity, the mDE nanoparticles appear to be a promising matrix for invertase immobilization as well as for other biomolecules.

  9. High sucrolytic activity by invertase immobilized onto magnetic diatomaceous earth nanoparticles.

    Science.gov (United States)

    Cabrera, Mariana P; Assis, Caio R D; Neri, David F M; Pereira, Claudete F; Soria, Fernando; Carvalho, Luiz B

    2017-03-01

    Invertase immobilized on magnetic diatomaceous earth nanoparticles (mDE-APTES-invertase) with high sucrolytic activity was obtained by an easy and low-cost method. An experimental design was carried out to investigate the best immobilization conditions and it allowed obtaining an immobilized derivative with a residual specific activity equal to 92.5%. Then, a second experimental design selected the mDE-APTES-invertase with higher specific activity in relation to other derivatives reported in the literature (2.42-fold). Thermal and storage stability for immobilized invertase were found to be 35 °C for 60 min (85% retained activity) and 120 days storage period (80% retained activity), respectively. Besides, a residual activity higher than 60% and 50% were observed for mDE-APTES-invertase after reuse in short and long term, respectively. Given the simple and efficient method to obtain an immobilized derivative with high activity, the mDE nanoparticles appear to be a promising matrix for invertase immobilization as well as for other biomolecules.

  10. Flotation of Toxocara canis Eggs in Commercial Bleach and Effects of Bleach Treatment Times on Larval Development in These Eggs.

    Science.gov (United States)

    von Dohlen, Alexa Rosypal; Houk-Miles, Alice E; Zajac, Anne M; Lindsay, David S

    2017-04-01

    Toxocara canis is a common intestinal nematode of young dogs. Puppies contaminate the environment with large numbers of eggs that can embryonate and become infective in less than a month. Embryonated eggs are infectious for humans and other paratenic hosts. Most T. canis infections in humans are asymptomatic; however, migration of T. canis larvae in the eye and in the central nervous system can result in vision loss, blindness, and even death. The eggs of T. canis are highly resistant to harsh environmental conditions and routinely used chemical disinfectants. The objective of this study was to evaluate the effects of full-strength commercial bleach (5.25% sodium hypochlorite solution) treatment on development of T. canis eggs and to report our serendipitous finding that T. canis eggs in dog feces can float in passive fecal flotation tests using bleach. We also demonstrated that T. canis eggs could be identified using the McMaster's fecal eggs counting test using 100% bleach. Toxocara canis eggs collected from the feces of naturally infected 4-8 wk old puppies were treated with full-strength bleach (5.25% sodium hypochlorite solution) for 15 min, 30 min, 60 min, and 120 min; washed free of bleach smell by centrifugation; and resuspended in 0.1 N sulfuric acid solution to undergo larval development at room temperature for 18 days after exposure to bleach. Motile larvae were observed in T. canis eggs in all groups treated for 15-120 min and eggs continuously exposed to bleach for 18 days. Our results indicate that bleach may not be an appropriate disinfectant for dog kennels, cages, or laboratory utensils and work surfaces. Toxocara canis eggs are resistant to bleach treatment and continue to pose a risk for canine and human infections. Further study is needed to find the most appropriate methods for disinfection and removal of eggs to reduce the risk of transmission of this parasite.

  11. Enhanced activity of rare earth doped PtRu/C catalysts for methanol electro-oxidation

    International Nuclear Information System (INIS)

    An Xiaosha; Fan Youjun; Chen Dejun; Wang Qiang; Zhou Zhiyou; Sun Shigang

    2011-01-01

    Highlights: → The electrocatalytic activity of PtRuRE/C catalysts is higher than that of the JM PtRu/C for methanol oxidation (except for PtRuGd/C), generating a decreasing order of PtRuEu/C > PtRuEr/C > PtRuY/C > PtRuSm/C > PtRuLa/C > JM PtRu/C > PtRuGd/C. → The CO-tolerance performance of PtRuRE/C catalysts is better than JM PtRu/C. → The electronic effect of rare earth plays an important role in the catalytic performance of PtRuRE/C for methanol electrooxidation. - Abstract: PtRuRE/C catalysts were prepared through doping the commercial JM PtRu/C catalyst with rare earth (RE = La, Eu, Gd, Y, Sm and Er). The doping was conducted by chemical reduction and sintering treatment methods. The catalysts were characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the rare earth doping did not significantly change the average size of the JM PtRu/C particles, and modified the PtRu surface with two element states of the metal and oxide. Studies of cyclic voltammetry and chronoamperometry indicated that the electrocatalytic activity of PtRuRE/C catalysts was higher than that of the JM PtRu/C for methanol oxidation (except for PtRuGd/C), generating a decreasing order of PtRuEu/C > PtRuEr/C > PtRuY/C > PtRuSm/C > PtRuLa/C > JM PtRu/C > PtRuGd/C. It has revealed that among the PtRuRE/C catalysts the PtRuEu/C exhibited the best performance. In addition, the reaction process of methanol electrocatalytic oxidation on several catalysts was investigated by in situ FTIR spectroscopy at molecule level. The results demonstrated that the adsorbates derived from methanol dissociative adsorption on the catalysts were the linear-bonded CO (CO L ), and the CO-tolerance performance of PtRuRE/C catalysts was better than JM PtRu/C. It has revealed also that the electronic effect of rare earth plays an important role in the catalytic performance

  12. NASA Earth Science Disasters Program Response Activities During Hurricanes Harvey, Irma, and Maria in 2017

    Science.gov (United States)

    Bell, J. R.; Schultz, L. A.; Molthan, A.; Kirschbaum, D.; Roman, M.; Yun, S. H.; Meyer, F. J.; Hogenson, K.; Gens, R.; Goodman, H. M.; Owen, S. E.; Lou, Y.; Amini, R.; Glasscoe, M. T.; Brentzel, K. W.; Stefanov, W. L.; Green, D. S.; Murray, J. J.; Seepersad, J.; Struve, J. C.; Thompson, V.

    2017-12-01

    The 2017 Atlantic hurricane season included a series of storms that impacted the United States, and the Caribbean breaking a 12-year drought of landfalls in the mainland United States (Harvey and Irma), with additional impacts from the combination of Irma and Maria felt in the Caribbean. These storms caused widespread devastation resulting in a significant need to support federal partners in response to these destructive weather events. The NASA Earth Science Disasters Program provided support to federal partners including the Federal Emergency Management Agency (FEMA) and the National Guard Bureau (NGB) by leveraging remote sensing and other expertise through NASA Centers and partners in academia throughout the country. The NASA Earth Science Disasters Program leveraged NASA mission products from the GPM mission to monitor cyclone intensity, assist with cyclone center tracking, and quantifying precipitation. Multispectral imagery from the NASA-NOAA Suomi-NPP mission and the VIIRS Day-Night Band proved useful for monitoring power outages and recovery. Synthetic Aperture Radar (SAR) data from the Copernicus Sentinel-1 satellites operated by the European Space Agency were used to create flood inundation and damage assessment maps that were useful for damage density mapping. Using additional datasets made available through the USGS Hazards Data Distribution System and the activation of the International Charter: Space and Major Disasters, the NASA Earth Science Disasters Program created additional flood products from optical and radar remote sensing platforms, along with PI-led efforts to derive products from other international partner assets such as the COSMO-SkyMed system. Given the significant flooding impacts from Harvey in the Houston area, NASA provided airborne L-band SAR collections from the UAVSAR system which captured the daily evolution of record flooding, helping to guide response and mitigation decisions for critical infrastructure and public safety. We

  13. Ten years research activities in Earth observation at the Cyprus University of Technology

    Science.gov (United States)

    Hadjimitsis, Diofantos G.; Themistocleous, Kyriacos; Agapiou, Athos; Mamouri, Rodanthi; Nisantzi, Argyro; Papoutsa, Christiana; Tzouvaras, Marios; Neoclous, Kyriacos; Mettas, Christodoulos; Michaelides, Silas

    2017-09-01

    This paper presents the achievements for the last 10 years of the Remote Sensing and Geo-Environment Laboratory of the Cyprus University of Technology in the Earth observation through the ERATOSTHENES Research Centre. Over the past 10 years, the Centre has secured competitive research funding from various sources, such as the European Commission, the Cyprus Research Promotion Foundation, as well as industrial partners, having participated either as a coordinator or as a partner in more than 60 research projects. The research activities of the Centre encompass remote sensing and GIS applications in the fields of Cultural Heritage, Agriculture, Water Resource Management, Environment, Infrastructure, Marine Spatial Planning, Atmospheric, Air Pollution and Coastal Applications, Natural Resource Management and Hazard Assessment. The aim of this paper is to map the existing activities and identify the future trends and goals of the Eratosthenes Research Centre for the next 15 years.

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

    Science.gov (United States)

    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 < 0.05) differences were detected in L*, as well as in b* values, between initial (I) and post bleaching (PB) and between initial (I) and 3 months post-op. In contrast, there was no significant difference between PB and 3 months post-op. The a* values showed no statistically significant differences among the different time points. 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.

  15. 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...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...... characteristic of an erosive process that took place on human enamel. Depression areas, including the formation of craters, and exposure of enamel rods could also be detected. Conclusion: Bleaching effects on enamel morphology were randomly distributed throughout enamel surface and various degrees of enamel...

  16. Bleaching of hydroentangled greige cotton nonwoven fabrics without scouring

    Science.gov (United States)

    This work investigated whether a hydroentangled greige cotton nonwoven fabric made at a relatively high hydroentangling water pressure, say, 135-bar, could be successfully bleached to attain the desired whiteness, absorbency and other properties without traditional scouring. Accordingly, the scoured...

  17. Group separation of rare earth elements by liquid-liquid extraction for the neutron activation analysis of silicate rocks

    International Nuclear Information System (INIS)

    Wyttenbach, A.; Bajo, S.; Tobler, L.

    1983-01-01

    Rare earth elements are isolated as a group from neutron activated rock samples by a new radiochemical procedure based on extraction with thenoyltrifluoracetone/phenanthroline in CHCl 3 . The procedure consists of three extraction steps, obviates the use of inactive carriers and gives practically quantitative chemical yields, thereby avoiding fractionation of the individual rare earths. Details of the dissolution, chemical separations. and counting procedure are given together with an analysis of BCR-1. (author)

  18. Thermal refugia against coral bleaching throughout the northern Red Sea

    KAUST Repository

    Osman, Eslam O.

    2017-10-17

    Tropical reefs have been impacted by thermal anomalies caused by global warming that induced coral bleaching and mortality events globally. However, there have only been very few recordings of bleaching within the Red Sea despite covering a latitudinal range of 15° and consequently it has been considered a region that is less sensitive to thermal anomalies. We therefore examined historical patterns of sea surface temperature (SST) and associated anomalies (1982–2012) and compared warming trends with a unique compilation of corresponding coral bleaching records from throughout the region. These data indicated that the northern Red Sea has not experienced mass bleaching despite intensive Degree Heating Weeks (DHW) of >15°C-weeks. Severe bleaching was restricted to the central and southern Red Sea where DHWs have been more frequent, but far less intense (DHWs <4°C-weeks). A similar pattern was observed during the 2015–2016 El Niño event during which time corals in the northern Red Sea did not bleach despite high thermal stress (i.e. DHWs >8°C-weeks), and bleaching was restricted to the central and southern Red Sea despite the lower thermal stress (DHWs < 8°C-weeks). Heat stress assays carried out in the northern (Hurghada) and central (Thuwal) Red Sea on four key reef-building species confirmed different regional thermal susceptibility, and that central Red Sea corals are more sensitive to thermal anomalies as compared to those from the north. Together, our data demonstrate that corals in the northern Red Sea have a much higher heat tolerance than their prevailing temperature regime would suggest. In contrast, corals from the central Red Sea are close to their thermal limits, which closely match the maximum annual water temperatures. The northern Red Sea harbours reef-building corals that live well below their bleaching thresholds and thus we propose that the region represents a thermal refuge of global importance.

  19. Effect of a New Bleaching Gel on Tooth Whitening

    Science.gov (United States)

    2016-05-12

    Effect of a New Bleaching Gel on Tooth Whitening Maj Tonya N. Barry APPROVED: Date APPROVED: Dean, Air Force Post aduate Dental School...UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES AIR FORCE POSTGRADUATE DENTAL SCHOOL 2450 Pepperrell Street Lackland AFB Texas, 78236-5345 http...reduced chair time and cost, high success rate, and safety of materials.6 2 Furthermore, bleaching teeth with 10% carbamide peroxide (the

  20. Biological and advanced treatment of sulfate pulp bleaching effluents

    International Nuclear Information System (INIS)

    Çeçen, F.; Urban, W.; Haberl, R.

    1992-01-01

    Spent bleaching effluents (from chlorination (C) and extraction (E) stages) of a sulfate pulp mill were subjected to bench-scale biological and advanced treatment. Although > 90 % of the influent BOD 5 could be removed in an activated sludge process, the effluent still contained high amounts of resistant substances. The maximum COD removal was about 50 %; the removal rates achieved in the parameters TOC, DOC, AOX, SAK (254 nm) were even lower. The biological treatment led to an increase in color (436 nm) up to 40 %. The biologically pretreated effluent was further treated by ozone or ozone/irradiation. The DOC, COD, color (436 nm), SAK (254 nm) and AOX removal rates amounted to 61 %, 81 %, 98 %, 92 % and 92 %, respectively. These methods led simultaneously to an increase in biological biodegradability as reflected by an increase in BOD 5 . A comparison of the results obtained for raw and biologically pretreated wastewaters showed that biodegradable substances should first be removed from the wastewater since otherwise the effectiveness of these methods decreased. The coagulation/flocculation of biologically pretreated effluent showed that FeCl3 was the most effective coagulant and that removal rates > 90 % could be achieved. The treatment with various powder activated carbons showed that a dosage of 10 g/l was required to achieve elimination rates > 90 % in the parameters DOC, COD, color (436 nm) and SAK (254 nm). Adsorption isotherms were developed for every activated carbon and adsorption constants were calculated. (author)

  1. Study on the activated laser welding of ferritic stainless steel with rare earth elements yttrium

    Science.gov (United States)

    Wang, Yonghui; Hu, Shengsun; Shen, Junqi

    2015-10-01

    The ferritic stainless steel SUS430 was used in this work. Based on a multi-component activating flux, composed of 50% ZrO2, 12.09 % CaCO3, 10.43 % CaO, and 27.49 % MgO, a series of modified activating fluxes with 0.5%, 1%, 2%, 5%, 10%, 15%, and 20% of rare earth (RE) element yttrium (Y) respectively were produced, and their effects on the weld penetration (WP) and corrosion resistant (CR) property were studied. Results showed that RE element Y hardly had any effects on increasing the WP. In the FeCl3 spot corrosion experiment, the corrosion rates of almost all the samples cut from welded joints turned out to be greater than the parent metal (23.51 g/m2 h). However, there was an exception that the corrosion rate of the sample with 5% Y was only 21.96 g/m2 h, which was even better than parent metal. The further Energy Dispersive Spectrometer (EDS) test showed the existence of elements Zr, Ca, O, and Y in the molten slag near the weld seam while none of them were found in the weld metal, indicating the direct transition of element from activating fluxes to the welding seam did not exist. It was known that certain composition of activating fluxes effectively restrain the loss of Cr element in the process of laser welding, and as a result, the CR of welded joints was improved.

  2. Neutron-activation determination of the rare earths in natural calcites using a semiconductor detector

    International Nuclear Information System (INIS)

    Vaganov, N.A.; Bulnaev, A.I.; Mejer, V.A.; Ponomarev, V.S.

    1976-01-01

    The application of germanium semiconducting detector is described. The detector has an energy resolution about 1 KeV and makes it possible to determine the content of Ce, Nd, Eu, Gd, Tb, and Yb in natural calcites with high sensitivity. The region of soft γ-radiation of activated calcites is more favourable for measurements to be performed than the region of hard γ-rays. Semiconducting detectors of radiation type are relatively cheap; they can be stored at room temperature. The limit of determining rare earth elements in calcites is (g): Eu-1.5.10 -9 ; Tb-4.0.10 -9 ; Yb-7.0.10 -9 ; Ce-1.0.10 -7 ; Nd-5.0.10 -7 ; Gd-1.0.10 -6 . A relative error of concentration determination is 10-20%

  3. Spectroscopic assessment of rare-earth activated planar waveguides and microcavities

    International Nuclear Information System (INIS)

    Zampedri, Luca; Tosello, Cristiana; Portales, Herve; Montagna, Maurizio; Mattarelli, Maurizio; Chiappini, Andrea; Righini, Giancarlo C.; Pelli, Stefano; Conti, Gualtiero Nunzi; Martino, Maurizio; Portal, Sabine; Marques, Ana C.; Almeida, Rui M.; Jestin, Yoann; Ferrari, Maurizio; Chiasera, Alessandro

    2005-01-01

    This paper deals with glass-based photonic structures, used to control and modify the optical and spectroscopic properties of rare earth ions. The spectroscopic assessment of sol-gel-derived planar waveguides and 1D photonic band gap structures is reported. The spectroscopic, optical, and structural properties of planar waveguides with (100 - x)SiO 2 -xHfO 2 -yErO 1.5 with y = 0.3, 0.01; and x = 10, 20, 30, 40 have been investigated by photoluminescence and Raman spectroscopy. The radiative quantum efficiency of the 4 I 13/2 metastable state of Er 3+ ions is between 84 and 88% depending on the Si/Hf molar ratio. The sol-gel-derived one-dimensional cavity was realized by a Eu 3+ -activated dielectric layer placed between distributed Bragg reflectors (DBRs)

  4. Analysis of low levels of rare earths by radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Wandless, G.A.; Morgan, J.W.

    1985-01-01

    A procedure for the radiochemical neutron activation analysis for the rare earth elements (REE) involves the separation of the REE as a group by rapid ion exchange methods and determination of yields by reactivation or by energy dispersive x-ray fluorescence spectrometry. The US Geological Surveys (USGS) standard rocks, BCR-1 and AGV-1, were analyzed to determine the precision and accuracy of the method. Authors found that the precision was +-5-10% on the basis of replicate analysis and that, in general the accuracy was within +-5% of accepted values for most REE. Data for USGS standard rocks BIR-1 (Icelandic basalt) and DNC-1 (North Carolina diabase) are also presented. (author)

  5. "Sustainability On Earth" WebQuests: Do They Qualify as Problem-Based Learning Activities?

    Science.gov (United States)

    Leite, Laurinda; Dourado, Luís; Morgado, Sofia

    2015-02-01

    Information and communication technologies (ICT), namely the Internet, can play a valuable educational role in several school subjects, including science education. The same applies to problem-based learning (PBL), that is, a student-centered active learning methodology that can prepare students for lifelong learning. WebQuests (WQs) combine PBL and Internet use, and they can reduce the probability of having students surfing the Internet without any clear purpose. The objective of this paper is to investigate to what extent WQs available from Portuguese schools' and universities' websites, focusing on the "Sustainability on Earth" eighth-grade school science theme, are consistent with a PBL perspective. Results from content analysis of 92 WQs indicate that the WQs selected for this paper are rarely consistent with PBL requirements. Teachers should be both aware of this issue and ready to improve the WQs available before using them in their science classes so that greater educational advantage can be generated from this powerful tool.

  6. 'Ethnic cleansing' bleaches the atrocities of genocide.

    Science.gov (United States)

    Blum, Rony; Stanton, Gregory H; Sagi, Shira; Richter, Elihu D

    2008-04-01

    Genocide has been the leading cause of preventable violent death in the 20th-21st century, taking even more lives than war. The term 'ethnic cleansing' is used as a euphemism for genocide despite it having no legal status. Like 'Judenrein' and 'racial hygiene' in Nazi medicine, it expropriates pseudo-medical terminology to justify massacre. Use of the term reifies a dehumanized view of the victims as sources of filth and disease, and propagates the reversed social ethics of the perpetrators. Timelines for recent genocides (Bosnia, 1991-1996, 200,000; Kosovo 1998-2000, 10,000-20,000; Rwanda, 1994, 800,000; Darfur 2002-2006, >400,000) show that its use bears no relationship to death tolls or the scale of atrocity. Bystanders' use of the term 'ethnic cleansing' signals the lack of will to stop genocide, resulting in huge increases in deaths, and undermines international legal obligations to acknowledge genocide. The term 'ethnic cleansing' corrupts observation, interpretation, ethical judgment and decision-making, thereby undermining the aim of public health. Public health should lead the way in expunging the term 'ethnic cleansing' from official use. 'Ethnic cleansing' bleaches the atrocities of genocide, leading to inaction in preventing current and future genocides.

  7. Clinical Evaluation of Genotoxicity of In-office Bleaching.

    Science.gov (United States)

    Rezende, M; De Geus, J L; Loguercio, A D; Reis, A; Kossatz, D

    The aim of this study was to evaluate the genotoxicity of in-office bleaching with 35% hydrogen peroxide in epithelial cells from the gingival and lip tissues. Thirty volunteers with central incisors shade A1 or darker were selected for this study. The gingival tissue of the teeth to be bleached was isolated with a light-polymerized resin dam, and the 35% hydrogen peroxide gel was administered during three 15-minute applications over the course of the 45-minute application period. Two bleaching sessions with a one-week interval in between were performed. Exfoliated oral mucosa gingival epithelial cells and upper lip lining were collected at baseline and one month after the in-office dental bleaching. The scraped cells were placed on clean glass slides and smears were prepared. After staining with Giemsa solution, two blinded examiners performed cell and micronuclei counts under a 100× optical microscope. Tooth sensitivity was evaluated using the Visual Analogue Scale (VAS). Shade evaluation was recorded before and one month after the bleaching treatment with the value-oriented shade guide Vita Bleachedguide 3D-MASTER and the spectrophotometer Vita Easyshade. Data from the shade guide units and the micronuclei (MN) frequency were subjected to a Mann-Whitney test (α=0.05). The overall difference between before and one month after the bleaching treatment (ΔE and ΔSGU), absolute risk, and intensity of tooth sensitivity (TS) were calculated, as was the 95% confidence interval (CI). The frequency of MN was not increased after bleaching with 35% hydrogen peroxide in both study groups (p>0.05). The absolute risk of TS of the participants was 93% (95% CI, 79%-98%), with a mean VAS intensity of 5.7 ± 2.9 (95% CI, 4.6-6.8). Meaningful whitening was observed after bleaching. The change in shade guide units in the Bleachedguide 3D-MASTER was 2.3 ± 1.4. In terms of ΔE, the change in color was 7.7 ± 3.5. The in-office bleaching did not induce DNA damage to the gingival

  8. Quantifying bleaching for zero-age fluvial sediment: A Bayesian approach

    International Nuclear Information System (INIS)

    Cunningham, Alastair C.; Evans, Mary; Knight, Jasper

    2015-01-01

    Luminescence dating of sediment requires the sand grains to have been exposed to sunlight prior to their most recent burial. Under fluvial transport, the amount of sunlight exposure may not always be sufficient to reset the luminescence signal, a phenomenon known as ‘partial bleaching'. The extent of bleaching is dependent on a combination of geomorphic, sedimentological and fluvial processes. If bleaching can be quantified, and the relationship with these processes understood, it could potentially be used as a new environmental proxy for changes in the dynamics of river systems. Here, we use a recently developed statistical model to evaluate the extent of bleaching, by inferring the proportion of well-bleached grains in the small-aliquot population. We sampled low-flow and flood deposits at a single site on the River Sabie, South Africa. We show that the low-flow sediment is almost perfectly bleached (>80% of grains well bleached), while sediment at flood elevations is partially bleached (20–70 % of grains well bleached). The degree of bleaching may show a relationship with flood magnitude as defined by elevation above normal river level, and we speculate on the causes of variability in bleaching between flood samples. - Highlights: • We sampled modern river sediment from low-flow and flood elevations. • The unbleached OSL dose was measured. • Bayesian methods can estimate the proportion of well-bleached grains. • Low-flow sediments are well bleached; flood deposits are poorly bleached.

  9. Molecular analysis of tooth enamel by Raman spectroscopy after treatment with bleaching agents at different concentrations

    International Nuclear Information System (INIS)

    Duran Sedo, Randall; Obando Rosabal, Sofia; Saenz Bonilla, Paola; Soto Aguilar, Calendy; Vasquez Rodriguez, Amaya

    2014-01-01

    The changes in the concentration of the v1 phosphate molecule of the surface of dentin enamel are treated and researched with bleaching agents of chemical activation to basis of hydrogen peroxide than 9,5% and 14% and carbamide peroxide than 38%, for a period of 28 days. Raman spectroscopy was used and 30 dental pieces extracted, of which, were to be free of blemishes and pigmentations, without possessing fractures of the enamel, decay nor any other type of defect. The Raman spectrum was obtained of each dental piece prior to the application of bleaching agents. The specimens were separated into three experimental groups according to the concentration of whitening. The concentration of the v1 phosphate molecule was measured in the tooth enamel to the second and fourth week of treatment. In addition, ANOVA was performed for respective measurements (p≤0.05). A reduction of the v1 phosphate molecule were observed during and after the bleaching process in the experimental groups that have used of hydrogen peroxide to 14% and carbamide peroxide 38%. In the group of hydrogen peroxide to 9,5% has remained unproven a significant reduction. Within the limitations of this study is concluded that the bleaching agent causes a loss of v1 phosphate. This loss has been greater in the whitening of higher concentration. In spite, that the possible effect remineralizing of the saliva on a teeth whitening process has been unevaluated, it is recommended using during and after the treatment, toothpastes, mouthwashes, chewing gums, dental floss, among others, that contain ACP to help to cushion the potential loss of phosphate from tooth enamel. (author) [es

  10. Histopathology of Inhalation of Industrial Bleach and Detergent Mixture on Epithelial Layer of Trachea in Mice

    Directory of Open Access Journals (Sweden)

    Gh. Vaezi

    2011-11-01

    Full Text Available This study is the effects of inhalation toxic mixture of bleach and detergent was examined on the epithelial layer of trachea in the mice. In this study, 42 adult male mice NMRI race weighing 35-40 gr and from age 8 to 10 weeks were divided into 6 experimental groups and one control group. Experimental groups 1-2-3 with the using of chamber, as inhalation 20 minutes were exposure to spray the amount 1 cc of mixture of bleach and detergent by nebulizer. Experimental groups 4-5-6 were for 35 minutes to inhale the same amount of material. Mice killed at 24-48-72 hours after inhalation and the trachea was studied pathology. In microscopic sections of tissue taken from the trachea the experimental group compared with the control group was changed to include: stimulation and activation of the respiratory epithelium hungarian (Mocusa layer, reducing the length of ciliated columnar cells, reducing the number of goblet cells ,loss of cilia, chaos and clutter on the order of tissue. In addition, statistically, the changes in length of ciliated columnar epithelium cells in experimental groups 3 and 6 seen significantly decreased than control group and the number of experimental groups 2 and 4 goblet cells significantly increased compared to control group, experimental group 6 was significantly decreased than the control group. As a result discussion, increasing the inhalation time of mixing bleach and detergent, also as time passed, cause to increase the tissue damage and changes.

  11. 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.

  12. Cleaning Spent Bleaching Clay through Using Solvent Extraction Method and RSM Statistical Approach

    Directory of Open Access Journals (Sweden)

    Mahsa Shahi

    2015-12-01

    Full Text Available Abstract. Bleaching clay refers to clays that in their natural or activated state have the capacity to absorb dyes and other remaining undesirable ingredients from edible oil during its purification processes. Thus, the most important function of bleaching clay is to improve the appearance, flavor, odor, and stability of the final oil product. Hexane, acetone, and methyl ethyl ketone were used as the solvents in this research, and RSM (response surface methodology was employed for determining the optimal parameters. The variable parameters included the solvent to clay ratio (SCR and the extraction time. Results showed methyl ethyl ketone with the final oil removal efficiency of 61.3% was superior to hexane and acetone, with efficiencies of 52.7 and 59.1%, respectively. Under the best laboratory conditions and using RSM, the highest extraction efficiency was 5.97 ml/g for the ketone solvents (acetone and methyl ethyl ketone at the extraction time of 3 minutes and 6 seconds, and 5.92 ml/g for hexane at the extraction time of 24 minutes and 30 seconds.Keywords: Cleaning, Spent Bleaching Clay, Solvent Extraction, Response Surface Methodology (RSM, Oil Purification

  13. Cleaning Spent Bleaching Clay through Using Solvent Extraction Method and RSM Statistical Approach

    Directory of Open Access Journals (Sweden)

    mahsa shahi

    2015-07-01

    Full Text Available Bleaching clay refers to clays that in their natural or activated state have the capacity to absorb dyes and other remaining undesirable ingredients from edible oil during its purification processes. Thus, the most important function of bleaching clay is to improve the appearance, flavor, odor, and stability of the final oil product. Hexane, acetone, and methyl ethyl ketone were used as the solvents in this research, and RSM (response surface methodology was employed for determining the optimal parameters. The variable parameters included the solvent to clay ratio (SCR and the extraction time. Results showed methyl ethyl ketone with the final oil removal efficiency of 61.3% was superior to hexane and acetone, with efficiencies of 52.7 and 59.1%, respectively. Under the best laboratory conditions and using RSM, the highest extraction efficiency was 5.97 ml/g for the ketone solvents (acetone and methyl ethyl ketone at the extraction time of 3 minutes and 6 seconds, and 5.92 ml/g for hexane at the extraction time of 24 minutes and 30 seconds. Key words: Cleaning, Spent Bleaching Clay, Solvent Extraction, Response Surface Methodology (RSM, Oil Purification

  14. Exploring near Earth object’s activity with cubesats: low surface brightness

    Science.gov (United States)

    Fuentes, Cesar; Diaz, Marcos; Falcon, Claudio; Clerc, Marcel

    2015-11-01

    Ever smaller Near Earth Objects (NEOs) continue to be discovered, with most potentially hazardous ones already surveyed and ongoing plans for space missions to deflect and mine them in the near future. These transitional objects in relatively unstable orbits have recently experienced collisional or dynamical encounters that have sent them to Earth’s vicinity. Finding comet-like activity (sublimation and ejected dust) is necessary to understand their origin, recent history, and evolution. Mommert et al (2014) have recently discovered cometary activity on the third largest NEO (3552) Don Quixote using near-Infrared imaging from Spitzer/IRAC they detect both a coma and tail as extended emission they identify as CO2 ice sublimation. This activity has gone unnoticed due to either sporadic activity or the relatively low surface brightness in optical wavelengths of light reflecting off dust, 26 mag/arcsec2 which necessarily imposes an extreme bias against detection. We propose to find this activity directly in the optical by going above the atmosphere.We are developing a 6U Cubesat to carry a 20cm aperture telescope. The volume restrictions impose a deployment system design for the telescope. We will study the optimal mission and optical setup for our goals, including the feasibility of a novel coronagraph to increase the sensitivity. Detecting NEO activity requires stability and low instrumental noise over many hours. Atmosphere’s varying point spread function (PSF), coupled with the extended PSF of reflective telescopes, lead us to propose to develop the concept and technology to manage a refractive telescope in space with the potential inclusion of a coronagraph, optimized for detecting faint features near bright targets. The experiment considers targeting nearby NEOs and optimizing observations for low surface brightness.

  15. Geodynamic evolution of the Earth over the Phanerozoic: Plate tectonic activity and palaeoclimatic indicators

    Directory of Open Access Journals (Sweden)

    Christian Vérard

    2015-04-01

    In this paper, we compare values derived from the tectonic model (ages of oceanic floor, production and subduction rates, tectonic activity with a combination of chemical proxies (namely CO2, 87Sr/86Sr, glaciation evidence, and sea-level variations known to be strongly influenced by tectonics. One of the outstanding results is the observation of an overall decreasing trend in the evolution of the global tectonic activity, mean oceanic ages and plate velocities over the whole Phanerozoic. We speculate that the decreasing trend reflects the global cooling of the Earth system. Additionally, the parallel between the tectonic activity and CO2 together with the extension of glaciations confirms the generally accepted idea of a primary control of CO2 on climate and highlights the link between plate tectonics and CO2 in a time scale greater than 107 yr. Last, the wide variations observed in the reconstructed sea-floor production rates are in contradiction with the steady-state model hypothesized by some.

  16. Determination of rare earth elements in mineral raw materials and rare earth industry products by neutron activation analysis

    International Nuclear Information System (INIS)

    Shmanenkova, G.I.; Shchelkova, V.P.; Uritskya, T.P.; Volkova, L.V.

    1991-01-01

    To determine REE in mineral raw materials, high purity RE metals and their compounds, neutron activation analysis with extraction chromatographic REE separation has been developed. Combination of the developed RE extraction and separation procedures with subsequent γ-spectrometric analysis of the RE radionuclides allows to determine their content with the lower detection limit -10 -5 -10 -8 %. The relative standard deviation is 0.2-0.3. (author) 2 refs.; 3 figs.; 6 tabs

  17. On a relation of geomagnetic activity, solar wind velocity and irregularity of daily rotation of the Earth

    International Nuclear Information System (INIS)

    Kalinin, Yu.D.; Kiselev, V.M.

    1980-01-01

    A possibility of the presence of statistic relation between the changes of the Earth rotation regime and the mean velocity of solar wind is discussed. The ratio between the solar wind velocity observed and planetary index of geomagnetic activity am is used to determine the annual average values of solar wind velocity beyond the twentieth cycle of solar activity. The restored changes of solar wind velocity are compared with solar conditioned variations of the Earth day duration and it is shown that the correspondence takes place only at frequencies lower the frequency of 11-year cycle [ru

  18. Anaerobic biodegradability and toxicity of wastewaters from chlorine and total chlorine-free bleaching of eucalyptus kraft pulps.

    NARCIS (Netherlands)

    Vidal, G.; Soto, M.; Field, J.; Mendez-Pampin, R.; Lema, J.M.

    1997-01-01

    Chlorine bleaching effluents are problematic for anaerobic wastewater treatment due to their high methanogenic toxicity and low biodegradability. Presently, alternative bleaching processes are being introduced, such as elemental chlorine-free (ECF) and total chlorine-free (TCF) bleaching. The

  19. Earth as Building Material – an overview of RILEM activities and recent Innovations in Geotechnics

    Directory of Open Access Journals (Sweden)

    Vyncke Johan

    2018-01-01

    Full Text Available This paper presents an overview of the different earth building techniques, the latest innovations and the normative aspects. The oldest man made earth constructions known to exist date back to 10 000 BC. Since then, earth has remained a popular building material throughout history. With time, different techniques evolved, starting from sundried adobe blocks to cob constructions, rammed earth walls and compressed earth bricks. Today these techniques are still being optimized and alternative binders, specifically adapted admixtures and surface treatments are being developed. Even though nearly one third of the world’s population lives in an earth construction, few specific building standards and testing methods exist. Many of the tests used today are based on tests for concrete and thus do not take into account the complex nature of earth constructions, such as their sensitivity to water. RILEM, the union of Laboratories and Experts in Construction Materials, Systems and Structures, set up a new Technical Committee in 2016: TC TCE (Testing and Characterisation of Earth-based building materials and elements. This committee, consisting of an international group of experts on the topic, aim to define testing procedures for earth as a building construction material. To end with, this paper also gives a short introduction to “Deep soil mixing”, an “earth” building technique dedicated to geotechnical engineering.

  20. Evaluation of pH Levels and Surface Roughness After Bleaching and Abrasion Tests of Eight Commercial Products.

    Science.gov (United States)

    Trentino, Ana Carolina; Soares, Ana Flavia; Duarte, Marco Antonio Hungaro; Ishikiriama, Sérgio Kiyoshi; Mondelli, Rafael Francisco Lia

    2015-07-01

    This in vitro study evaluated the effect of different bleaching protocols and the variation of pH levels of bleaching gels regarding roughness and wear of bovine enamel, after in-office bleaching protocols and brushing. Ninety fragments were randomly divided into nine groups: C, control; WHP15, 35% hydrogen peroxide (HP) (Whiteness HP, FGM) three gel applications of 15 min each, three sessions with 1 week intervals; WHP45, 35% HP (Whiteness HP) one application/45 min, three sessions with 1 week intervals; LPS, 35% HP (Lase Peroxide, DMC) plus hybrid light (HL) [light-emitting diode (LED)/diode laser], four applications/7 min 30 sec (6 min of HL activation), one session; LPSII, 25% HP (Lase Peroxide II, DMC) plus HL, four applications/7 min 30 sec (6 min of HL activation), one session; LPL, 15% HP (Lase Peroxide Light, DMC) four applications/7 min 30 sec (6 min of HL activation), one session; WO, 35% HP (Whitegold Office, Dentsply) three applications/15 min, three sessions with 1 week intervals; WBC40, 35% HP (Whiteness HP Blue Calcium, FGM) one application/40 min, three sessions with 1 week intervals; and WBC50, 20% HP (Whiteness HP Blue Calcium) one application/50 min, three sessions with 1 week intervals. The median pH values were determined utilizing a pH meter during the initial and final gel applications. A rugosimeter was utilized to evaluate the surface roughness (Ra) before and after bleaching and brushing (100,000 strokes), and the surface wear after brushing. For the results of the pH values, there was a decrease in the pH levels from the initial to the final bleaching time, except for the WBC50. The WO and WBC40 groups exhibited higher pH values. For the results of roughness and wear, there was an increase in surface roughness and wear among the groups. The pH values tended to decrease from the initial to the final bleaching. After tooth brushing, bleaching procedures with lower pH products provided a significant increase in

  1. 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.

  2. 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.

  3. Stress-Activated Electric Currents in the Earth Crust: How they Can and Cannot Flow (Invited)

    Science.gov (United States)

    Freund, F. T.; Bleier, T. E.; Bortnik, J.; Dahlgren, R.

    2010-12-01

    Dormant electronic charge carriers exist in rocks. They “wake up” when stresses are applied: electrons e’ and positive holes, h., the latter being defect electrons in the oxygen anion sublattice of minerals [1, 2]. The h. can flow out of the stressed subvolume. They can spread into the unstressed surrounding, turning the rocks into p-type semiconductors. They travel fast and far using energy levels at the upper edge of the valence bands. Contrary to the h., the co-activated electrons e’ cannot flow out and propagate through unstressed rocks: they are stuck in the activation volume. The situation is akin to that in an electrochemical battery except that, in the “rock battery”, the positive charge carriers are not cations but positive holes h.. In the laboratory it is easy to close the battery circuit by offering the electrons a metal contact and connecting the stressed and unstressed rock with a metal wire. This is useful to demonstrate the functioning of the “rock battery”. In the field the h. outflow from a stressed rock volume is restricted as long as there is no return path. This is an important point when we try to understand why pre-earthquake EM emission is widely considered “unreliable” [3, 4]. However, there are at least three conditions, under which circuit closure can be achieved in the field under realistic pre-earthquake situations: (i) via n-type conducting rocks; (ii) via electrolytic conductivity of water; and (iii) via the air when the air above the epicentral region becomes highly ionized. We report on examples where these three conditions might have allowed large currents to flow and strong EM signals to be emitted. [1] Freund, F.T. et al.: Electric currents streaming out of stressed igneous rocks - A step towards understanding pre-earthquake low frequency EM emissions, Phys. Chem. Earth 31, 389-396 (2006). [2] Freund, F.T.: Charge generation and propagation in rocks, J. Geodyn. 33, 545-572 (2002). [3] Johnston, M.J.S. and

  4. Quantification of the efficiency for photo-bleached pigments using cellulose matrixes as substrate and digitalized gray scale

    Science.gov (United States)

    Florez, F. L. E.; Correia Lins, E. C. C.; Lizarelli, R. F. Z.; Bagnato, V. S.

    2006-02-01

    The bleaching process is been objective of many studies since the beginning of the XX century. Heat has been used to activate the hydrogen peroxide; the aesthetic results were satisfactory, but associated with this process high incidence of hypersensitivity as well as radical endodontic treatment was observed making this technique clinically hard to implemented. Nowadays the dental bleaching is one of the most wanted aesthetic procedures by the population at the dental office. With the utilization of new light sources as LASER and LED a technique to evaluate the efficiency of photo-bleaching of many pigments is necessary. This work demonstrates a new method to quantify the breakage of pigments on a cellulose matrix using a blue LED system with 1W/cm2. We employed a computational analysis and digital spectroscopy. These matrixes were used because of its inert physical-chemical properties. The obtained results are within the expectative, where the groups irradiated with light presents more broken pigments that the group with no light, it was also possible to observe on this experiment that light acts decreasing the free energy of the reaction and that way speeding up the rate of bleaching.

  5. Experimentally Induced Bleaching in the Sea Anemone Exaiptasia Supports Glucose as a Main Metabolite Associated with Its Symbiosis

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Molina

    2017-01-01

    Full Text Available Our current understanding of carbon exchange between partners in the Symbiodinium-cnidarian symbioses is still limited, even though studies employing carbon isotopes have made us aware of the metabolic complexity of this exchange. We examined glycerol and glucose metabolism to better understand how photosynthates are exchanged between host and symbiont. The levels of these metabolites were compared between symbiotic and bleached Exaiptasia pallida anemones, assaying enzymes directly involved in their metabolism. We measured a significant decrease of glucose levels in bleached animals but a significant increase in glycerol and G3P pools, suggesting that bleached animals degrade lipids to compensate for the loss of symbionts and seem to rely on symbiotic glucose. The lower glycerol 3-phosphate dehydrogenase but higher glucose 6-phosphate dehydrogenase specific activities measured in bleached animals agree with a metabolic deficit mainly due to the loss of glucose from the ruptured symbiosis. These results corroborate previous observations on carbon translocation from symbiont to host in the sea anemone Exaiptasia, where glucose was proposed as a main translocated metabolite. To better understand photosynthate translocation and its regulation, additional research with other symbiotic cnidarians is needed, in particular, those with calcium carbonate skeletons.

  6. Investigation of three home-applied bleaching agents on enamel structure and mechanical properties: an in situ study

    Science.gov (United States)

    Sa, Yue; Wang, Zhejun; Ma, Xiao; Lei, Chang; Liang, Shanshan; Sun, Lili; Jiang, Tao; Wang, Yining

    2012-03-01

    The safety of at-home tooth bleaching, based upon carbamide peroxide (CP) or hydrogen peroxide (HP) as the active agent, has been questioned. The aim of the present study was to investigate the effects of three differently concentrated home-applied bleaching agents on human enamel under in situ conditions. Sixty specimens were divided randomly into four groups and treated with 10% CP, 15% CP, 20% CP, and distilled water, respectively. Raman spectroscopy, attenuated total reflectance-infrared (ATR-IR) spectroscopy, atomic force microscopy (AFM), microhardness, and fracture toughness (FT) measurements were conducted to determine variations on enamel structure and mechanical properties before and after the bleaching process. Raman revealed little variation of Raman relative intensity after treatment with CP, which was consistent with the results of ATR-IR, AFM, and microhardness analyses. In addition, laser-induced fluorescence (LIF) intensity, and FT showed significant decreases on CP-treated specimens. These findings suggested there were minimal demineralization effects of the three at-home bleaching agents on enamel in situ. However, the decrease of LIF intensity and FT on enamel seemed to be inevitable.

  7. Detection of geodynamic activity areas based on the Earth's electromagnetic noise parameters

    Science.gov (United States)

    Gordeev, Vasily F.; Malyshkov, Sergey Yu; Shtalin, Sergey G.; Polivach, Vitaly I.; Krutikov, Vladimir A.

    2016-11-01

    In this paper, a method of using the Earth's natural pulsed electromagnetic noise for mapping of anomalies of intensely strained state of the Earth's crust is substantiated. Examples of using the method for mapping of geodynamically dangerous sites and monitoring of processes that pose threats to the operation of industrial facilities are presented.

  8. The Discovery of Cometary Activity in Near-Earth Asteroid Don Quixote

    NARCIS (Netherlands)

    Mommert, Michael; Hora, Joseph L.; Harris, Alan W.; Reach, William T.; Emery, Joshua P.; Thomas, Cristina A.; Mueller, Michael; Cruikshank, Dale P.; Trilling, David E.; Delbo, Marco; Smith, Howard A.

    2014-01-01

    The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552)

  9. Mars Exploration: Is There Water on Mars? An Educator's Guide with Activities for Physical and Earth and Space Science.

    Science.gov (United States)

    TERC, Cambridge, MA.

    This educator's guide discusses whether there is water on the planet Mars. The activities, written for grades 9-12, concern physical, earth, and space sciences. By experimenting with water as it changes state and investigating some effects of air pressure, students not only learn core ideas in physical science but can also deduce the water…

  10. Bleach gel: a simple agarose gel for analyzing RNA quality.

    Science.gov (United States)

    Aranda, Patrick S; LaJoie, Dollie M; Jorcyk, Cheryl L

    2012-01-01

    RNA-based applications requiring high-quality, non-degraded RNA are a foundational element of many research studies. As such, it is paramount that the integrity of experimental RNA is validated prior to cDNA synthesis or other downstream applications. In the absence of expensive equipment such as microfluidic electrophoretic devices, and as an alternative to the costly and time-consuming standard formaldehyde gel, RNA quality can be quickly analyzed by adding small amounts of commercial bleach to TAE buffer-based agarose gels prior to electrophoresis. In the presence of low concentrations of bleach, the secondary structure of RNA is denatured and potential contaminating RNases are destroyed. Because of this, the 'bleach gel' is a functional approach that addresses the need for an inexpensive and safe way to evaluate RNA integrity and will improve the ability of researchers to rapidly analyze RNA quality. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 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

  12. Earth materials and earth dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, K; Shankland, T. [and others

    2000-11-01

    In the project ''Earth Materials and Earth Dynamics'' we linked fundamental and exploratory, experimental, theoretical, and computational research programs to shed light on the current and past states of the dynamic Earth. Our objective was to combine different geological, geochemical, geophysical, and materials science analyses with numerical techniques to illuminate active processes in the Earth. These processes include fluid-rock interactions that form and modify the lithosphere, non-linear wave attenuations in rocks that drive plate tectonics and perturb the earth's surface, dynamic recrystallization of olivine that deforms the upper mantle, development of texture in high-pressure olivine polymorphs that create anisotropic velocity regions in the convecting upper mantle and transition zone, and the intense chemical reactions between the mantle and core. We measured physical properties such as texture and nonlinear elasticity, equation of states at simultaneous pressures and temperatures, magnetic spins and bonding, chemical permeability, and thermal-chemical feedback to better characterize earth materials. We artificially generated seismic waves, numerically modeled fluid flow and transport in rock systems and modified polycrystal plasticity theory to interpret measured physical properties and integrate them into our understanding of the Earth. This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

  13. Using rare earth element tracers and neutron activation analysis to study rill erosion process

    International Nuclear Information System (INIS)

    Li Mian; Li Zhanbin; Ding Wengfeng; Liu Puling; Yao Wenyi

    2006-01-01

    Spatially averaged soil erosion data provide little information on the process of rill erosion. The dynamically varied data on the temporal and spatial distributions in the rill erosion process are needed to better understand the erosion process and reveal its innate characteristics. The objectives of this study were to examine the feasibility and effectiveness of rare earth element (REE) tracers and the neutron activation analysis (NAA) method on the study of the rill erosion process and to reveal quantitatively the relationships and characteristics of temporal and spatial distributions of sediment yield in rill erosion. Four REEs were used to study the changeable process of rill erosion at 4 slope positions. Four water inflow rates were applied to a 0.3x5 m soil bed at 3 slopes of 10.5%, 15.8% and 21.2% in scouring experiments. All of the runoff was collected in the experiment. Each sample was air-dried and well mixed. Then 20 g of each sample was sieved through 100-mesh and about a 50 mg sample was weighed for analysis of the four elemental compositions by NAA. Results indicate that the REE tracers and NAA method can be used to not only quantitatively determine soil erosion amounts on different slope segments, but also to reveal the changeable process of rill erosion amount. All of the relative errors of the experimental results were less than 25%, which is considered satisfactory on the study of rill erosion process

  14. Rare-earth elements in Egyptian granite by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    El-Taher, A. [Physics Department, Faculty of Science, Al-Azher University, Assuit Branch (Egypt)]. E-mail: Atef_Eltaher@hotmail.com

    2007-04-15

    The mobilization of rare-earth elements (REEs) in the environment requires monitoring of these elements in environmental matrices, in which they are mainly present at trace levels. The similarity in REEs chemical behavior makes the separate determination of each element by chemical methods difficult; instrumental neutron activation analysis (INAA), based on nuclear properties of the elements to be determined, is a method of choice in trace analysis of REEs and related elements. Therefore, INAA was applied as a sensitive nondestructive analytical tool for the determination of REEs to find out what information could be obtained about the REEs of some Egyptian granite collected from four locations in Aswan area in south Egypt as follows wadi El-Allaqi, El-Shelal, Gabel Ibrahim Pasha and from Sehyel Island and to estimate the accuracy, reproducibility and detection limit of NAA method in case of the given samples. The samples were properly prepared together with standards and simultaneously irradiated in a neutron flux of 7x10{sup 11} n/cm{sup 2} s in the TRIGA Mainz research reactor facilities. The following elements have been determined: La, Ce, Nd, Sm, Eu, Yb and Lu. The gamma spectra was collected by HPGe detector and the analysis was done by means of computerized multichannel analyzer. The X-ray fluorescence (XRF) was also used.

  15. Effect of bleaching on the microhardness of tooth-colored restorative materials

    Directory of Open Access Journals (Sweden)

    Abdolrahim Davari

    2013-08-01

    Full Text Available   Background and Aims: Bleaching agents not only affect the tooth structure, but also may alter the properties of restorative materials. The aim of this in vitro study was to evaluate the effect of different bleaching regimens on the microhardness of four tooth-colored restorative materials.   Materials and Methods: Eighty specimens of four restorative materials (Microhybrid resin composite (Z250 (3M, ESPE, nanohybrid composite Z350 (3M, ESPE, packable composite P60 (3M, ESPE, and resin modified glass ionomer Vitremer (3M, ESPE were fabricated and were polished after 24 h with Soflex discs (3M,ESPE. Then the specimens were divided into two groups: In office bleach group, 40 specimens (10 of each restorative material were bleached with hydrogen peroxide 37.5% for 30 min in two sessions with 7 days interval. In home bleaching group, 40 specimens were bleached with carbamid peroxide 22%, 6 h a day for 14 days. Vickers microhardness test were done before and after bleaching (baseline. Finally data were evaluated using analysis of Variance.   Results: Two bleaching regimens were significantly decreased the microhardness values. In Z250 resin composite, the microhardness values before and after bleaching were 95.30 and 92.67 kg/mm2, respectively. for office bleaching (P=0.011 and 95.38 and 92.39 kg/mm2 for home bleaching (P<0.001. In Z350 resin composite, the microhardness values before and after bleaching were 98.29 and 92.41 kg/mm2, for office bleaching (P<0.001 and 97.35 and 93.44 kg/mm2 for home bleaching (P<0.001 respectively. In P60 resin composite, the microhardness values before and after bleaching were 103.10 and 96.16 kg/mm2, respectively. for office bleaching (P=0.045 and 102.61 and 98.16 kg/mm2 for home bleaching (P=0.001. In resin modified glass ionomer (Vitremer, the microhardness values before and after bleaching were 56.79 and 49.41 kg/mm2, respectively. for office bleaching (P=0.004 and 54.17 and 46.50 kg/mm2 for home bleaching (P

  16. Environmental Drivers of Variation in Bleaching Severity of Acropora Species during an Extreme Thermal Anomaly

    OpenAIRE

    Mia O. Hoogenboom; Mia O. Hoogenboom; Grace E. Frank; Grace E. Frank; Tory J. Chase; Tory J. Chase; Saskia Jurriaans; Saskia Jurriaans; Mariana Álvarez-Noriega; Mariana Álvarez-Noriega; Katie Peterson; Kay Critchell; Kathryn L. E. Berry; Kathryn L. E. Berry; Kathryn L. E. Berry

    2017-01-01

    High sea surface temperatures caused global coral bleaching during 2015–2016. During this thermal stress event, we quantified within- and among-species variability in bleaching severity for critical habitat-forming Acropora corals. The objective of this study was to understand the drivers of spatial and species-specific variation in the bleaching susceptibility of these corals, and to evaluate whether bleaching susceptibility under extreme thermal stress was consistent with that observed duri...

  17. Remote Sensing of Coral Bleaching Using Temperature and Light: Progress towards an Operational Algorithm

    OpenAIRE

    William Skirving; Susana Enríquez; John D. Hedley; Sophie Dove; C. Mark Eakin; Robert A. B. Mason; Jacqueline L. De La Cour; Gang Liu; Ove Hoegh-Guldberg; Alan E. Strong; Peter J. Mumby; Roberto Iglesias-Prieto

    2017-01-01

    The National Oceanic and Atmospheric Administration’s Coral Reef Watch program developed and operates several global satellite products to monitor bleaching-level heat stress. While these products have a proven ability to predict the onset of most mass coral bleaching events, they occasionally miss events; inaccurately predict the severity of some mass coral bleaching events; or report false alarms. These products are based solely on temperature and yet coral bleaching is known to result from...

  18. 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

  19. Reducing bleaching effects in organic nanofibers by coating

    DEFF Research Database (Denmark)

    Tavares, Luciana; Kjelstrup-Hansen, Jakob; Rubahn, Horst-Günter

    Para-hexaphenylene (p-6P) organic nanofibers emit polarized, blue light upon UV excitation with a peak wavelength of the emitted light of 425 nm [1] and a spatially anisotropic distribution of the emitted light [2]. These features could enable future (opto-)electronic applications [3], since......, we present results of systematic bleaching experiments, in which we have investigated diverse mono- and multilayer coating materials. It is found that the most promising combination results in a significant reduction of bleaching without affecting significantly the emission spectrum....

  20. Mineral Physics Research on Earth's Core and UTeach Outreach Activities at UT Austin

    Science.gov (United States)

    Lin, J.; Wheat, A. J.

    2011-12-01

    Comprehension of the alloying effects of major candidate light elements on the phase diagram and elasticity of iron addresses pressing issues on the composition, thermal structures, and seismic features of the Earth's core. Integrating this mineral physics research with the educational objectives of the CAREER award was facilitated by collaboration with the University of Texas at Austin's premier teaching program, UTeach. The UTeach summer outreach program hosts three one-week summer camps every year exposing K-12th graders to university level academia, emphasizing math and science initiatives and research. Each week of the camp either focuses on math, chemistry, or geology. Many of the students were underrepresented minorities and some required simultaneous translation; this is an effect of the demographics of the region, and caused some language barrier challenges. The students' opportunity to see first-hand what it is like to be on a university campus, as well as being in a research environment, such as the mineral physics lab, helps them to visualize themselves in academia in the future. A collection of displayable materials with information about deep-Earth research were made available to participating students and teachers to disseminate accurate scientific knowledge and enthusiasm. These items included a diamond anvil cell and diagrams of the diamond crystal structure, the layers of the Earth, and the phases of carbon to show that one element can have very different physical properties purely based on differences in structure. The students learned how advanced X-ray and optical laser spectroscopies are used to study properties of planetary materials in the diamond anvil cell. Stress was greatly placed on the basic mathematical relationship between force, area, and pressure, the fundamental principle involved with diamond anvil cell research. Undergraduate researchers from the lab participated in the presentations and hands-on experiments, and answered any

  1. 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.

  2. On causes of the low seismic activity in the Earth's polar latitudes

    Science.gov (United States)

    Levin, Boris; Sasorova, Elena; Domanski, Andrei

    2016-04-01

    The irregularity of distribution of seismic activity in the world was observed at the beginning of the era of instrumental seismology (B. Gutenberg, C. Richter, K. Kasahara). At the same time, the global nature of the symmetry of this effect has been established only in this millennium, with the participation of authors (Levin B.W., Sasorova E.V., 2010). Analysis of the global earthquake catalogs showed that almost all seismic events over the last century occurred within a limited latitudinal band contained between the 65 N and 65 S. The seismic activity in the polar regions of the planet was manifested very weakly. The reasons for such features were found by following the analysis of the characteristics associated with the theory of the figure of the Earth. In the works of the French mathematician A. Veronne (1912) was the first to introduce the concept of "critical" latitudes (φ1 = ±35°15' 22″) wherein the radius of the ellipsoid of revolution is equal to the radius of the sphere of the same volume. Variation of the radius vector of the ellipsoid at this latitude is equal to zero. There is the boundary between the compressed areas of the polar zones and equatorial region, where the rocks of the Earth are dominated by tensile forces. Analysis of the specific characteristics of the gravity force distribution on the surface of the ellipsoid has shown that there is a distribution of the same character with a singular point at latitude φ2 = ±61° 52' 12″. In case of variations in the angular velocity of the planet's rotation the variation of gravity force at the latitude φ2 is negligible, compared with variations of gravity force on the equator and pole, which exceed the previous value by 3-4 orders. Attempted analysis of the model of the ellipsoid of revolution in the theory of axisymmetric elastic shells has allowed to establish that in the elastic shell of the planet must occur meridional and ring forces. The theory shows that when the flatness (or polar

  3. Effectiveness of bleaching agent on composite resin discoloration

    Directory of Open Access Journals (Sweden)

    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

  4. 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)

  5. 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

  6. Cloud Computing Applications in Support of Earth Science Activities at Marshall Space Flight Center

    Science.gov (United States)

    Molthan, Andrew L.; Limaye, Ashutosh S.; Srikishen, Jayanthi

    2011-01-01

    Currently, the NASA Nebula Cloud Computing Platform is available to Agency personnel in a pre-release status as the system undergoes a formal operational readiness review. Over the past year, two projects within the Earth Science Office at NASA Marshall Space Flight Center have been investigating the performance and value of Nebula s "Infrastructure as a Service", or "IaaS" concept and applying cloud computing concepts to advance their respective mission goals. The Short-term Prediction Research and Transition (SPoRT) Center focuses on the transition of unique NASA satellite observations and weather forecasting capabilities for use within the operational forecasting community through partnerships with NOAA s National Weather Service (NWS). SPoRT has evaluated the performance of the Weather Research and Forecasting (WRF) model on virtual machines deployed within Nebula and used Nebula instances to simulate local forecasts in support of regional forecast studies of interest to select NWS forecast offices. In addition to weather forecasting applications, rapidly deployable Nebula virtual machines have supported the processing of high resolution NASA satellite imagery to support disaster assessment following the historic severe weather and tornado outbreak of April 27, 2011. Other modeling and satellite analysis activities are underway in support of NASA s SERVIR program, which integrates satellite observations, ground-based data and forecast models to monitor environmental change and improve disaster response in Central America, the Caribbean, Africa, and the Himalayas. Leveraging SPoRT s experience, SERVIR is working to establish a real-time weather forecasting model for Central America. Other modeling efforts include hydrologic forecasts for Kenya, driven by NASA satellite observations and reanalysis data sets provided by the broader meteorological community. Forecast modeling efforts are supplemented by short-term forecasts of convective initiation, determined by

  7. Coral bleaching and associated mortality in Mayotte, Western Indian ...

    African Journals Online (AJOL)

    Manta tows in fringing and barrier reef areas, together with observations, were used to estimate the extent of the bleaching and associated coral mortality in Mayotte between 1 and 24 of May 2010. Three areas around the island were surveyed. The results from fringing reefs in the north coast of Mayotte showed that nearly ...

  8. Photo-bleaching of polymer discoloration caused by quinone methides

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Jan; Nešpůrek, Stanislav; Zweifel, H.; Kuthan, J.

    2002-01-01

    Roč. 78, č. 2 (2002), s. 251-255 ISSN 0141-3910 R&D Projects: GA AV ČR IAA1050901 Institutional research plan: CEZ:AV0Z4050913 Keywords : quinone methide * photo-bleaching * polymer discoloration Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.145, year: 2002

  9. Assessing Coral Community Recovery from Coral Bleaching by ...

    African Journals Online (AJOL)

    The densities of small colonies were lowest at the northern sites, and small colonies of genera of corals that suffered from high bleaching and mortality during the El Niño Southern Oscillation in 1998 were less abundant in the north. These northern reefs are relatively isolated from sources of coral larvae from reefs in the ...

  10. Bleaching and/or porcelain veneers: case reports.

    Science.gov (United States)

    Putter, H

    1992-01-01

    Four case studies are presented in which the concept that bleaching, porcelain veneer restorations, or a combination of both constitute a conservative treatment approach for discolored, malformed, malaligned, and worn dentition. These treatments can be used effectively not only for aging dentitions, but also for the very young, which makes them an attractive treatment modality.

  11. 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.

  12. Influence of local environmental conditions and bleaching histories ...

    African Journals Online (AJOL)

    Here, 10 reef-building coral samples were collected from different reefs along the Tanzanian coast with different micro-environments and bleaching histories. The ITS-2 region of ribosomal DNA was employed in the characterisation of Symbiodinium harboured by reef-building corals. DGGE fingerprints and DNA sequences ...

  13. Project Overview: A Reef Manager's Guide to Coral Bleaching ...

    Science.gov (United States)

    The purpose of this report is to provide the latest scientific knowledge and discuss available management options to assist local and regional managers in responding effectively to mass coral bleaching events. Background A Reef Manager’s Guide to Coral Bleaching is the result of a collaborative effort by over 50 scientists and managers to: (1) share the best available scientific information on climate-related coral bleaching; and (2) compile a tool kit of currently available strategies for adaptive management of coral reefs in a changing climate. The result is a compendium of current information, tools, and practical suggestions to aid managers in their efforts to protect reefs in a way that maximizes reef resilience in the face of continuing climate change. The Guide is a joint publication of the National Oceanic and Atmospheric Administration, the Great Barrier Reef Marine Park Authority, and The World Conservation Union, with author contributions from a variety of international partners from government agencies, non-governmental organizations, and academic institutions. EPA’s Office of Research and Development was a major contributor to the Guide through authorship and participation in the final review and editing process for the entire report. A Reef Manager’s Guide to Coral Bleaching is the result of a collaborative effort by over 50 scientists and managers to: (1) share the best available scientific information on climate-related coral blea

  14. Guest–host interactions in the alkaline bleaching of ...

    Indian Academy of Sciences (India)

    Administrator

    534 ported that in fading of triphenylmethane dye addi- tion of alcohol retards the rate. There is similarity between CD catalysed and micellar catalysed reac- tion of bleaching of the triphenylmethane dyes for water reaction. For RA, CD decelerates the rate of both water and hydroxide ion reaction (table 4). This is contrary to.

  15. Bleached and unbleached MFC nanobarriers: properties and hydrophobisation with hexamethyldisilazane

    Energy Technology Data Exchange (ETDEWEB)

    Chinga-Carrasco, Gary, E-mail: gary.chinga.carrasco@pfi.no [Paper and Fibre Research Institute (PFI) (Norway); Kuznetsova, Nina; Garaeva, Milyausha [Kazan National Research Technological University (KNRTU) (Russian Federation); Leirset, Ingebjorg [Paper and Fibre Research Institute (PFI) (Norway); Galiullina, Guzaliya; Kostochko, Anatoly [Kazan National Research Technological University (KNRTU) (Russian Federation); Syverud, Kristin [Paper and Fibre Research Institute (PFI) (Norway)

    2012-12-15

    This study explores the production and surface modification of microfibrillated cellulose (MFC), based on unbleached and bleached Pinus radiata pulp fibres. Unbleached Pinus radiata pulp fibres tend to fibrillate easier by homogenisation without pre-treatment, compared to the corresponding bleached MFC. The resulting unbleached MFC films have higher barrier against oxygen, lower water wettability and higher tensile strength than the corresponding bleached MFC qualities. In addition, it is demonstrated that carboxymethylation can also be applied for production of highly fibrillated unbleached MFC. The nanofibril size distribution of the carboxymethylated MFC is narrow with diameters less than 20 nm, as quantified on high-resolution field-emission scanning electron microscopy images. The carboxymetylation had a larger fibrillation effect on the bleached pulp fibres than on the unbleached one. Importantly, the suitability of hexamethyldisilazane (HMDS) as a new alternative for rendering MFC films hydrophobic was demonstrated. The HMDS-modified films made of carboxymethylated MFC had oxygen permeability levels better than 0.06 mL mm m{sup -2} day{sup -1} atm{sup -1}, which is a good property for some packaging applications.

  16. Bleached and unbleached MFC nanobarriers: properties and hydrophobisation with hexamethyldisilazane

    Science.gov (United States)

    Chinga-Carrasco, Gary; Kuznetsova, Nina; Garaeva, Milyausha; Leirset, Ingebjørg; Galiullina, Guzaliya; Kostochko, Anatoly; Syverud, Kristin

    2012-12-01

    This study explores the production and surface modification of microfibrillated cellulose (MFC), based on unbleached and bleached Pinus radiata pulp fibres. Unbleached Pinus radiata pulp fibres tend to fibrillate easier by homogenisation without pre-treatment, compared to the corresponding bleached MFC. The resulting unbleached MFC films have higher barrier against oxygen, lower water wettability and higher tensile strength than the corresponding bleached MFC qualities. In addition, it is demonstrated that carboxymethylation can also be applied for production of highly fibrillated unbleached MFC. The nanofibril size distribution of the carboxymethylated MFC is narrow with diameters less than 20 nm, as quantified on high-resolution field-emission scanning electron microscopy images. The carboxymetylation had a larger fibrillation effect on the bleached pulp fibres than on the unbleached one. Importantly, the suitability of hexamethyldisilazane (HMDS) as a new alternative for rendering MFC films hydrophobic was demonstrated. The HMDS-modified films made of carboxymethylated MFC had oxygen permeability levels better than 0.06 mL mm m-2 day-1 atm-1, which is a good property for some packaging applications.

  17. Coral Bleaching and Associated Mortality at Mayotte, Western Indian ...

    African Journals Online (AJOL)

    the 1998 ENSO event. Acknowledgement–We thank Benjamin. Esperance, la Direction de l'Agriculture et de la Forêt (DAF), and Léonard Durasnel and Said Mohammed, Conseil General de. Mayotte, for supporting this study. Table 1. Genera commonly bleached at Mayotte in May 2010, listed in the order of the degree and.

  18. POM-assisted electrochemical delignification and bleaching of chemical pulp

    Science.gov (United States)

    Helene Laroche; Mohini Sain; Carl Houtman; Claude Daneault

    2001-01-01

    A polyoxometalate-catalyzed electrochemical process has shown good selectivity in delignifying pulp. This breakthrough in redox catalysis shows promise for the development of a new environmentally benign technology for pulp bleaching. The electrochemical process, applied with a mildly alkaline electrolyte solution containing trace amounts of a vanadium-based...

  19. Bleach Solution Requirement for Hatching of Daphnia magna Resting Eggs

    Directory of Open Access Journals (Sweden)

    Catur Retnaningdyah

    2016-11-01

    Full Text Available Daphnia (water fleas belong to the zooplankton group called Cladocerans have sexual reproduction when conditions less favorable that produce diapausing eggs are enclosed in the ephippium. Hatching ephippial eggs in the laboratory is important in ecological, toxicology, genetical, and evolutionary studies. This study aims to improve the current methods of egg hatching from ephippium. Each of 50 ephippium were treated together by placing them in a glass jar and adding 50 mL bleach solution (sodium hypochlorite. Concentrations of sodium hypochlorite used in this experiment were 0%, 0.5%, 1%, 2%, 4% and 8%. These concentration treatments were crossed with the following exposure times (1, 2, 4, 8, 16, and 32 minutes. Culturing was done in 80 mL of artificial Daphnia medium, incubated in constant light and temperatures 20°C for 25 days. There were two repetitions in this experiment that were run at the same time. Result of this experiment showed that pretreatment with 0.5-8% bleach solution significantly increases the yield of total hatch rate of Daphnia magna resting eggs by about 21% over unbleached control. However, there was no significant difference among the bleach treatments. Concentration of bleach solution 0.5%, 1% and 4% significantly accelerated the time period until the first hatching (first day hatching. Difference of exposure time (1 - 32 minutes at each concentration treatments were not influence the yield of total hatch and the time period until first hatching.

  20. Natural and recombinant fungal laccases for paper pulp bleaching

    NARCIS (Netherlands)

    Sigoillot, C.; Record, E.; Belle, V.; Robert, J.L.; Levasseur, A.; Punt, P.J.; Hondel, C.A.M.J.J. van den; Fournel, A.; Sigoillot, J.C.; Asther, M.

    2004-01-01

    Three laccases, a natural form and two recombinant forms obtained from two different expression hosts, were characterized and compared for paper pulp bleaching. Laccase from Pycnoporus cinnabarinus, a well known lignolytic fungus, was selected as a reference for this study. The corresponding

  1. Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef ...

    African Journals Online (AJOL)

    user1

    Differential bleaching susceptibility among scleractinian corals has been documented both in the field in Okinawa, Japan (Loya et al. 2001), on the Great Barrier Reef, Australia (Marshall &. Baird, 2000; Baird & Marshall, 2002), and in the Indian Ocean (Spencer et al. 2000) and under experimental trials (Fitt & Warner, 1995; ...

  2. Intra-pulpal temperature rise of different tooth types during dental bleaching supported by an Er,Cr:YSGG laser. A pilot study.

    Science.gov (United States)

    Strakas, D; Tolidis, K; Koliniotou-Koumpia, E; Vanweersch, L; Franzen, R; Gutknecht, N

    2016-01-01

    The purpose of this pilot in vitro study was to evaluate the temperature increase in the pulp chamber of the teeth, during Er,Cr:YSGG bleaching, as well as to show which teeth are the most susceptible in terms of pulp temperature increase during laser-activated bleaching treatment. Although Er:YAG studies have been published on this subject, it is the first time Er,Cr:YSGG wavelength is tested. Fifteen teeth were tested--3 each of the following--(maxillary central incisors, lateral incisors, canines, premolars and mandibular incisors). The bleaching procedure comprised an Er,Cr:YSGG laser (2780 nm, Waterlase MD, Biolase, USA) and a yellow-coloured bleaching agent with a concentration of 38 % H2O2 (Power whitening, WHITEsmile GmbH, Germany). The tip used was a 6-mm long Z-type glass tip (MZ8) of a 800 μm diameter. Average output power was set to 1.25 W, pulse duration 700 μs (S-mode), whilst the pulse repetition rate was 10 Hz. The results showed that the most susceptible teeth in terms of pulp temperature increase were the lateral maxillary incisors and the mandibular incisors. The mean temperature increase on these teeth was 1.06 and 1.00 °C, respectively, on 60 s Er,Cr:YSGG-supported bleaching.

  3. Assessing dentin color changes from nightguard vital bleaching.

    Science.gov (United States)

    McCaslin, A J; Haywood, V B; Potter, B J; Dickinson, G L; Russell, C M

    1999-10-01

    At-home bleaching with 10 percent carbamide peroxide in a custom-fitted tray has been reported to change the color of dentin. The purpose of this study was to validate the color change of dentin and to determine whether the color change was uniform or occurred from the outside (the dentinoenamel junction) to the inside (the pulpal wall). The authors sectioned 10 extracted human teeth incisogingivally through the midfacial long axis, and sealed their cut surface against glass microscope slides. Identifying marks were placed on the glass over the tooth sections to serve as a color control and in the dentinal areas closest to the dentinoenamel junction and the pulpal wall. Teeth were bleached for 10 days with 10 percent carbamide peroxide. Photographs were taken from the glass-covered side of the teeth, digitized and converted to gray-scale levels (consisting of 256 shades of gray ranging from black to white). Marked areas were measured with a National Institutes of Health Image software program and analyzed statistically for changes in lightness between the control marks and the inner and outer dentinal marks over time. Paired t-tests and analysis of variance indicated a significant increase in lightness (P = .01) for the inner and outer dentinal areas during bleaching compared with the control areas. No significant differences were found in the rate of change for the inner and outer dentinal areas (P = .89). The increase in lightness confirms that a significant color change occurred in the dentin during bleaching with 10 percent carbamide peroxide. This change occurred throughout the dentin at a uniform rate, rather than from the outside inward. The results of this study show that at-home bleaching with 10 percent carbamide peroxide can change the color of dentin, which is important to treat intrinsic stains from tetracycline treatment, trauma and aging or inherited discolorations. The bleaching material easily penetrates the tooth to change the dentin color at the

  4. Bahan pemutih gigi dengan sertifikat ADA/ISO (Tooth bleaching material with ADA/ISO certificate

    Directory of Open Access Journals (Sweden)

    Asti Meizarini

    2005-06-01

    Full Text Available Bleaching of teeth for cosmetic reasons is a popular aspect of cosmetic dentistry because patients realize the aesthetical benefits of these products. The dentist as a clinician's practitioner must be knowledgeable of the products and their application techniques. Bleaching materials which are safe and effective are the ADA accepted or manufactured by those which have already haved ISO certificate. Dentist must have enough knowledge about in-office bleaching prescribed for home-use bleaching including their contra indication and side effects, to advise the patients and provide effective bleaching services.

  5. Large-scale bleaching of corals on the Great Barrier Reef.

    Science.gov (United States)

    Hughes, T P; Kerry, J T; Simpson, T

    2018-02-01

    In 2015-2016, record temperatures triggered a pan-tropical episode of coral bleaching. In the southern hemisphere summer of March-April 2016, we used aerial surveys to measure the level of bleaching on 1,156 individual reefs throughout the 2,300 km length of the Great Barrier Reef, the world's largest coral reef system. The accuracy of the aerial scores was ground-truthed with detailed underwater surveys of bleaching at 260 sites (104 reefs), allowing us to compare aerial and underwater bleaching data with satellite-derived temperatures and with associated model predictions of bleaching. The severity of bleaching on individual reefs in 2016 was tightly correlated with the level of local heat exposure: the southernmost region of the Great Barrier Reef escaped with only minor bleaching because summer temperatures there were close to average. Gradients in nutrients and turbidity from inshore to offshore across the Great Barrier Reef had minimal effect on the severity of bleaching. Similarly, bleaching was equally severe on reefs that are open or closed to fishing, once the level of satellite-derived heat exposure was accounted for. The level of post-bleaching mortality, measured underwater after 7-8 months, was tightly correlated with the aerial scores measured at the peak of bleaching. Similarly, reefs with a high aerial bleaching score also experienced major shifts in species composition due to extensive mortality of heat-sensitive species. Reefs with low bleaching scores did not change in composition, and some showed minor increases in coral cover. Two earlier mass bleaching events occurred on the Great Barrier Reef in 1998 and 2002, that were less severe than 2016. In 2016, reefs had no bleaching, compared to 42% in 2002 and 44% in 1998. Conversely, the proportion of reefs that were severely bleached (>60% of corals affected) was four times higher in 2016. The geographic footprint of each of the three events is distinctive, and matches satellite-derived sea

  6. Cloud Computing Applications in Support of Earth Science Activities at Marshall Space Flight Center

    Science.gov (United States)

    Molthan, A.; Limaye, A. S.

    2011-12-01

    Currently, the NASA Nebula Cloud Computing Platform is available to Agency personnel in a pre-release status as the system undergoes a formal operational readiness review. Over the past year, two projects within the Earth Science Office at NASA Marshall Space Flight Center have been investigating the performance and value of Nebula's "Infrastructure as a Service", or "IaaS" concept and applying cloud computing concepts to advance their respective mission goals. The Short-term Prediction Research and Transition (SPoRT) Center focuses on the transition of unique NASA satellite observations and weather forecasting capabilities for use within the operational forecasting community through partnerships with NOAA's National Weather Service (NWS). SPoRT has evaluated the performance of the Weather Research and Forecasting (WRF) model on virtual machines deployed within Nebula and used Nebula instances to simulate local forecasts in support of regional forecast studies of interest to select NWS forecast offices. In addition to weather forecasting applications, rapidly deployable Nebula virtual machines have supported the processing of high resolution NASA satellite imagery to support disaster assessment following the historic severe weather and tornado outbreak of April 27, 2011. Other modeling and satellite analysis activities are underway in support of NASA's SERVIR program, which integrates satellite observations, ground-based data and forecast models to monitor environmental change and improve disaster response in Central America, the Caribbean, Africa, and the Himalayas. Leveraging SPoRT's experience, SERVIR is working to establish a real-time weather forecasting model for Central America. Other modeling efforts include hydrologic forecasts for Kenya, driven by NASA satellite observations and reanalysis data sets provided by the broader meteorological community. Forecast modeling efforts are supplemented by short-term forecasts of convective initiation, determined by

  7. Effect of coffee 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. To evaluate the influence of beverages with coloring agents on bleached bovine incisors considering the time elapsed after bleaching. 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 (ppigmented with coffee presented ∆E values below 3.3 units for all evaluation times. The exposure to coffee after bleaching causes less color changes than the exposure to a CBSD regardless of the time after bleaching.

  8. 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 (pteeth 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

  9. Surface discoloration of composite resins: Effects of staining and bleaching

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2012-01-01

    Background: The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet•X HD, Clearfil AP-X, Gradia Direct) and five nanohybrid composite resins (Ceram•X, GC Kalore, G-aenial, Grandio, GrandioSO), after staining and bleaching procedures. Materials and Methods: The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany) into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness) to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h), for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco). The color of specimens was measured with a spectrophotometer according to the CIE L*a*b* system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DEab*) between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA). Results: All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Conclusions: Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested. PMID:23559921

  10. Surface discoloration of composite resins: Effects of staining and bleaching

    Directory of Open Access Journals (Sweden)

    Claudio Poggio

    2012-01-01

    Full Text Available Background: The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet·X HD, Clearfil AP-X, Gradia Direct and five nanohybrid composite resins (Ceram·X, GC Kalore, G-aenial, Grandio, GrandioSO, after staining and bleaching procedures. Materials and Methods: The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h, for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco. The color of specimens was measured with a spectrophotometer according to the CIE LFNx01aFNx01bFNx01 system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DE abFNx01 between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA. Results: All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Conclusions: Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

  11. Surface discoloration of composite resins: Effects of staining and bleaching.

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2012-09-01

    The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet•X HD, Clearfil AP-X, Gradia Direct) and five nanohybrid composite resins (Ceram•X, GC Kalore, G-aenial, Grandio, GrandioSO), after staining and bleaching procedures. The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany) into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness) to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h), for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco). The color of specimens was measured with a spectrophotometer according to the CIE L(*)a(*)b(*) system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DEab(*)) between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA). All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

  12. In-office dental bleaching with light vs. without light: A systematic review and meta-analysis.

    Science.gov (United States)

    Maran, Bianca Medeiros; Burey, Adrieli; de Paris Matos, Thalita; Loguercio, Alessandro D; Reis, Alessandra

    2018-03-01

    A systematic review and meta-analysis were performed to answer the following research question: Does light-activated in-office vital bleaching have a greater whitening efficacy and higher tooth sensitivity (TS) in comparison with in-office vital bleaching without light when used in adults? Only randomized clinical trials (RCTs) involving adults who had in-office bleaching with and without light activation were included. Controlled vocabulary and keywords were used in a comprehensive search for titles and abstracts in PubMed, and this search was adapted for Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE without restrictions in May 2016 and was updated in August 2017. IADR abstracts (1990-2016), unpublished- and ongoing-trial registries, dissertations, and theses were also searched. The risk-of-bias tool of the Cochrane Collaboration was used for quality assessment. The quality of the evidence was rated using the Grading of Recommendations: Assessment, Development, and Evaluation approach. Through the use of the random effects model, a meta-analysis with a subgroup analysis (low and high hydrogen peroxide concentration) was conducted for color change (ΔE*, ΔSGU) as well as the risk and intensity of TS. We retrieved 6663 articles, but after removing duplicates and non-relevant articles, only 21 RCTs remained. No significant difference in ΔE*, ΔSGU, and risk and intensity of TS was observed (p > .05). For ΔE and risk of TS, the quality of the evidence was graded as moderate whereas the evidence for ΔSGU and intensity of TS was graded as very low and low, respectively. Without considering variations in the protocols, the activation of in-office bleaching gel with light does not seem to improve color change or affect tooth sensitivity, regardless of the hydrogen peroxide concentration. (PROSPERO - CRD42016037630). Although it is commercially claimed that in-office bleaching associated with light improves and accelerates color change, this

  13. Tooth bleaching induces changes in the vascular permeability of rat incisor pulps.

    Science.gov (United States)

    Ferreira, Vanessa Guarino; Nabeshima, Cleber Keiti; Marques, Márcia Martins; Paris, Adriana Fraga Costa Samos; Gioso, Marco Antônio; dos Reis, Rodrigo Sant'anna Aguiar; Machado, Manoel Eduardo de Lima

    2013-10-01

    To evaluate the inflammatory response in dental pulps of rat incisors subjected to tooth bleaching protocols with different HP concentrations and application times. 42 incisors from Wistar rats were submitted to tooth bleaching using concentrations of 25% or 35% HP for treatment times of 15, 30 or 45 minutes. Four non-bleached teeth were used as controls. The animals received an intravenous injection of India ink immediately after the bleaching procedure and were sacrificed 1 hour later. Six bleached teeth from each group and three controls were made transparent, and one sample from each group was processed for histological analysis. The data were statistically analyzed using Kruskal Wallis and Dunn's tests (P ink content was significantly higher in the samples that were bleached with 35% HP for 30 minutes and with both HP concentrations (25 and 35%) for 45 minutes than in the controls. For the samples bleached with the same HP concentration, the ink content was higher in samples that were bleached for 45 minutes. These results indicate that HP tooth bleaching can induce an increase in vascular permeability in rat incisors. Importantly, this increase is more dependent on the length of the bleaching procedure than on the concentration of the bleaching agent.

  14. 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.

  15. 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.

  16. Effect of in-office bleaching agents on physical properties of dental composite resins.

    Science.gov (United States)

    Mourouzis, Petros; Koulaouzidou, Elisabeth A; Helvatjoglu-Antoniades, Maria

    2013-04-01

    The physical properties of dental restorative materials have a crucial effect on the longevity of restorations and moreover on the esthetic demands of patients, but they may be compromised by bleaching treatments. The purpose of this study was to evaluate the effects of in-office bleaching agents on the physical properties of three composite resin restorative materials. The bleaching agents used were hydrogen peroxide and carbamide peroxide at high concentrations. Specimens of each material were prepared, cured, and polished. Measurements of color difference, microhardness, and surface roughness were recorded before and after bleaching and data were examined statistically by analysis of variance (ANOVA) and Tukey HSD post-hoc test at P composite resin altered after the bleaching procedure (P composite resins tested (P > .05). The silorane-based composite resin tested showed some color alteration after bleaching procedures. The bleaching procedure did not alter the microhardness and the surface roughness of all composite resins tested.

  17. Response of sponges with autotrophic endosymbionts during the coral-bleaching episode in Puerto Rico

    Science.gov (United States)

    Vicente, V. P.

    1990-04-01

    An updated list of sponges with algal endosymbionts including new records for Puerto Rico and the Caribbean, indicates that thirty-five species of common Caribbean sponges possess photosynthetic endosymbionts. Of these, 23 (67.6%) species in seven orders, were found with unicellular chroococcoid cyanobacteria ( Aphanocapsa-like) and 5 (14.7%) hadromerid species were found with zooxanthellae. Sponges with other algae as symbionts occur less frequently (≦6%). Thirty-one common sponge species were inspected for bleaching during coral-bleaching months (July-September 1987; January 1988) in Puerto Rico. Anthosigmella varians, Xestospongia muta and Petrosia pellasarca bleached partially, but only few individuals within any given population became bleached and the bleaching of sponges was very localized. Adaptations between cyanobacterial symbionts and sponges, acquired during the long evolutionary history of these two taxa may explain the paucity of bleached sponges when compared to the high incidence of bleached corals reported.

  18. Environmental Drivers of Variation in Bleaching Severity of Acropora Species during an Extreme Thermal Anomaly

    Directory of Open Access Journals (Sweden)

    Mia O. Hoogenboom

    2017-11-01

    Full Text Available High sea surface temperatures caused global coral bleaching during 2015–2016. During this thermal stress event, we quantified within- and among-species variability in bleaching severity for critical habitat-forming Acropora corals. The objective of this study was to understand the drivers of spatial and species-specific variation in the bleaching susceptibility of these corals, and to evaluate whether bleaching susceptibility under extreme thermal stress was consistent with that observed during less severe bleaching events. We surveyed and mapped Acropora corals at 10 sites (N = 596 around the Lizard Island group on the northern Great Barrier Reef. For each colony, bleaching severity was quantified using a new image analysis technique, and we assessed whether small-scale environmental variables (depth, microhabitat, competition intensity and species traits (colony morphology, colony size, known symbiont clade association explained variation in bleaching. Results showed that during severe thermal stress, bleaching of branching corals was linked to microhabitat features, and was more severe at reef edge compared with lagoonal sites. Bleaching severity worsened over a very short time-frame (~1 week, but did not differ systematically with water depth, competition intensity, or colony size. At our study location, within- and among-species variation in bleaching severity was relatively low compared to the level of variation reported in the literature. More broadly, our results indicate that variability in bleaching susceptibility during extreme thermal stress is not consistent with that observed during previous bleaching events that have ranged in severity among globally dispersed sites, with fewer species escaping bleaching during severe thermal stress. In addition, shaded microhabitats can provide a refuge from bleaching which provides further evidence of the importance of topographic complexity for maintaining the biodiversity and ecosystem

  19. Preparation and photocatalytic activity of rare earth doped TiO2 nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Bakardjieva, Snejana; Murafa, Nataliya

    2009-01-01

    Roč. 114, č. 1 (2009), s. 217-226 ISSN 0254-0584 Institutional research plan: CEZ:AV0Z40320502 Keywords : anatase * urea * rare earth Subject RIV: CA - Inorganic Chemistry Impact factor: 2.015, year: 2009

  20. Prebiotic Chemistry and Atmospheric Warming of Early Earth by an Active Young Sun

    Science.gov (United States)

    Airapetian, V. S.; Glocer, A.; Gronoff, G.; Hebrard, E.; Danchi, W.

    2016-01-01

    Nitrogen is a critical ingredient of complex biological molecules. Molecular nitrogen, however, which was outgassed Into the Earth's early atmosphere, is relatively chemically inert and nitrogen fixation into more chemically reactive compounds requires high temperatures. Possible mechanisms of nitrogen fixation include lightning, atmospheric shock heating by meteorites, and solar ultraviolet radiation. Here we show that nitrogen fixation in the early terrestrial atmosphere can be explained by frequent and powerful coronal mass ejection events from the young Sun -- so-called superflares. Using magnetohydrodynamic simulations constrained by Kepler Space Telescope observations, we find that successive superflare ejections produce shocks that accelerate energetic particles, which would have compressed the early Earth's magnetosphere. The resulting extended polar cap openings provide pathways for energetic particles to penetrate into the atmosphere and, according to our atmospheric chemistry simulations, initiate reactions converting molecular nitrogen, carbon dioxide and methane to the potent greenhouse gas nitrous oxide as well as hydrogen cyanide, an essential compound for life. Furthermore, the destruction of N2, C02 and CH, suggests that these greenhouse gases cannot explain the stability of liquid water on the early Earth. Instead, we propose that the efficient formation of nitrous oxide could explain a warm early Earth.

  1. A Kinetic Insight into the Activation of n -Octane with Alkaline-Earth ...

    African Journals Online (AJOL)

    Alkaline-earth metal hydroxyapatites are prepared by the co-precipitation method and characterized using XRD, ICP,NH3-TPD, SEM-EDX, TEM and N2 physisorption analysis. The metal present in the hydroxyapatite influences the acidity of the catalyst. Oxidative dehydrogenation reactions carried out in a continuous flow ...

  2. Coral diseases and bleaching on Colombian Caribbean coral reefs

    Directory of Open Access Journals (Sweden)

    Raúl Navas-Camacho

    2010-05-01

    Full Text Available 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 (10x2m 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

  3. Relationships among thermal stress, bleaching and oxidative damage in the hermatypic coral, Pocillopora capitata.

    Science.gov (United States)

    Flores-Ramírez, Laura A; Liñán-Cabello, Marco A

    2007-01-01

    To examine the response to exposure to a thermal gradient in coral, we assessed the effect of a gradual 10 degrees C temperature increase (22 to 32 degrees C over 10 h) on normal (N), partially bleached (P) and control (C) samples collected from different branches of the same coral (Pocillopora capitata). We examined markers of oxidative stress, including lipid peroxidation (MDA) and superoxide dismutase (SOD) activity, indicators of bleaching, including chlorophyll a (Chl a) and carotenoid pigment (PC) levels, as well as zooxanthellae density. Our results revealed that N, P and C coral samples all contained higher levels of PC versus Chl a. The levels of both pigments increased as the temperature increased from 22 to 28 degrees C only in N and C samples, whereas P samples showed less cellular damage than N and C samples at temperatures between 26 and 28 degrees C, and had greater antioxidant activities at temperatures between 26 and 30 degrees C. The rate of zooxanthellar expulsion consistently increased with temperature in all three coral types across the entire temperature range. Collectively, these results indicate that temperature has a direct effect on the antagonistic relationship between temperature-induced damage and protective antioxidant mechanisms in this type of coral.

  4. Can an LED-laser hybrid light help to decrease hydrogen peroxide concentration while maintaining effectiveness in teeth bleaching?

    Science.gov (United States)

    Martín, J.; Ovies, N.; Cisternas, P.; Fernández, E.; Oliveira Junior, O. B.; de Andrade, M. F.; Moncada, G.; Vildósola, P.

    2015-02-01

    The aim of this study was to compare the bleaching efficacy of 35% hydrogen peroxide and 15% hydrogen peroxide with nitrogen-doped titanium dioxide catalysed by an LED-laser hybrid light. We studied 70 patients randomized to two groups. Tooth shade and pulpal sensitivity were registered. Group 1: 15% hydrogen peroxide with nitrogen-doped titanium dioxide. Group 2: 35% hydrogen peroxide. Both groups were activated by an LED-laser light. No significant differences were seen in shade change immediately, one week or one month after treatment (p > 0.05). Differences were seen in pulpal sensitivity (p concentration with similar aesthetic results and less pulpal sensitivity than using 35% hydrogen peroxide for bleaching teeth.

  5. Determination of rare earth elements, hafnium and cadmium in sintered pellets of mixed thorium and uranium oxides by neutron activation

    International Nuclear Information System (INIS)

    Cardoso, S.N.M.

    1987-01-01

    This work shows the development of a method for determination of the rare-earth elements (Eu, Sm, Dy and Gd), Hf and Cd contents in sinterized U and Th mixed oxides by neutron activation analysis. The sample is dissolved in nitric/fluoridric (0,1% HF) medium, to dryness and redissolved in 6N HCl solution. The Hf is extracted into organic phase (0,5 M TTA/benzene), irradiated and analysed through 181 Hf isotope energy peak. The aqueous phase is treated with NH 4 OH for the precipitation of hidroxides. Then, these are dissolved in 6N HNO 3 solution. The extraction of U and Th is made in two steps, one with TBP/CCl 4 and another with 0,5 M TTA/C 6 H 6 . Then the rare-earth elements and Cd are irradiated and determined by gamma spectrometry. (author) [pt

  6. 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.

  7. 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.

  8. 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.

  9. YouTube as a source of information on skin bleaching: a content analysis.

    Science.gov (United States)

    Basch, C H; Brown, A A; Fullwood, M D; Clark, A; Fung, I C-H; Yin, J

    2017-12-18

    Skin bleaching is a common, yet potentially harmful body modification practice. To describe the characteristics of the most widely viewed YouTube™ videos related to skin bleaching. The search term 'skin bleaching' was used to identify the 100 most popular English-language YouTube videos relating to the topic. Both descriptive and specific information were noted. Among the 100 manually coded skin-bleaching YouTube videos in English, there were 21 consumer-created videos, 45 internet-based news videos, 30 television news videos and 4 professional videos. Excluding the 4 professional videos, we limited our content categorization and regression analysis to 96 videos. Approximately 93% (89/96) of the most widely viewed videos mentioned changing how you look and 74% (71/96) focused on bleaching the whole body. Of the 96 videos, 63 (66%) of videos showed/mentioned a transformation. Only about 14% (13/96) mentioned that skin bleaching is unsafe. The likelihood of a video selling a skin bleaching product was 17 times higher in internet videos compared with consumer videos (OR = 17.00, 95% CI 4.58-63.09, P YouTube video on skin bleaching was uploaded by an internet source. Videos made by television sources mentioned more information about skin bleaching being unsafe, while consumer-generated videos focused more on making skin-bleaching products at home. © 2017 British Association of Dermatologists.

  10. Thermal stress exposure, bleaching response, and mortality in the threatened coral Acropora palmata.

    Science.gov (United States)

    Williams, D E; Miller, M W; Bright, A J; Pausch, R E; Valdivia, A

    2017-11-15

    Demographic data for Elkhorn coral, Acropora palmata, and in situ water temperature data from seven upper Florida Keys (USA) reefs revealed three warm thermal stress events between 2010 and 2016. During a mild bleaching event in 2011, up to 59% of colonies bleached, but no mortality resulted. In both 2014 and 2015, severe and unprecedented bleaching was observed with up to 100% of colonies bleached. A. palmata live tissue cover declined by one-third following the 2014-2015 events. Colony mortality of mildly- and non-bleached colonies did not differ but increased significantly with more severe bleaching. Increased bleaching prevalence corresponded to maximum daily average water temperatures above 31.3°C. However, the cumulative days with daily average exceeding 31.0°C provided a better predictor of bleaching response. The bleaching response of surviving colonies in 2015 was not consistent with acclimatization as most individual colonies bleached at least as badly as in 2014. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. 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)

  12. First Observations of a Foreshock Bubble at Earth: Implications for Magnetospheric Activity and Energetic Particle Acceleration

    Science.gov (United States)

    Turner, D. L.; Omidi, N.; Sibeck, D. G.; Angelopoulos, V.

    2011-01-01

    Earth?s foreshock, which is the quasi-parallel region upstream of the bow shock, is a unique plasma region capable of generating several kinds of large-scale phenomena, each of which can impact the magnetosphere resulting in global effects. Interestingly, such phenomena have also been observed at planetary foreshocks throughout our solar system. Recently, a new type of foreshock phenomena has been predicted: foreshock bubbles, which are large-scale disruptions of both the foreshock and incident solar wind plasmas that can result in global magnetospheric disturbances. Here we present unprecedented, multi-point observations of foreshock bubbles at Earth using a combination of spacecraft and ground observations primarily from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, and we include detailed analysis of the events? global effects on the magnetosphere and the energetic ions and electrons accelerated by them, potentially by a combination of first and second order Fermi and shock drift acceleration processes. This new phenomena should play a role in energetic particle acceleration at collisionless, quasi-parallel shocks throughout the Universe.

  13. Effects of bleaching on mercury ion release from dental amalgam.

    Science.gov (United States)

    Al-Salehi, S K

    2009-03-01

    The chemical reactions that take place at the amalgam surface when exposed to bleaching agents are not well-understood. It is known, however, that mercury ions are released from dental amalgam when bleached. We hypothesized that increasing concentrations of hydrogen peroxide are more effective than water at increasing mercury ion release from dental amalgam. We prepared dental amalgam discs (n = 65) by packing amalgam into cylindrical plastic molds and divided them into 13 equal groups of 5 discs each. The discs in each group were individually immersed in either 0%, 3.6%, 6%, or 30% (w/v) hydrogen peroxide at exposure periods of 1, 8, 48, and 168 hrs. Samples were taken for mercury ion release determination by inductively coupled plasma mass spectrometry. There were significant increases in mercury release between control and all other hydrogen peroxide concentrations at all exposure times (p < 0.05).

  14. Multicolor bleach-rate imaging enlightens in vivo sterol transport

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Sage, Daniel

    2011-01-01

    , dehydroergosterol (DHE) in the genetically tractable model organism Caenorhabditis elegans (C. elegans). DHE is structurally very similar to cholesterol and ergosterol, two sterols used by the sterol-auxotroph nematode. We developed a new computational method measuring fluorophore bleaching kinetics at every pixel...... with a lysosomal marker, GFP-LMP1. Our new methods hold great promise for further studies on endosomal sterol transport in C. elegans....

  15. Biodegradability and toxicity assessment of bleach plant effluents treated anaerobically.

    Science.gov (United States)

    Chaparro, T R; Botta, C M; Pires, E C

    2010-01-01

    As part of an experimental project on the treatment of bleach plant effluents the results of biodegradability and toxicity assessment of effluents from a bench-scale horizontal anaerobic immobilized bioreactor (HAIB) are discussed in this paper. The biodegradability of the bleach plant effluents from a Kraft pulp mill treated in the HAIB was evaluated using the modified Zahn-Wellens test. The inoculum came from a pulp mill wastewater treatment plant and the dissolved organic carbon (DOC) was used as the indicator of organic matter removal. The acute and chronic toxicity removal during the anaerobic treatment was estimated using Daphnia similis and Ceriodaphnia silvestrii respectively. Moreover, the evaluation of chromosome aberrations (CA), micronucleus frequencies (MN) and mitotic index (IM) in Allium cepa cells were used as genotoxicity indicators. The results indicate that the effluents from the anaerobic reactor are amenable to aerobic polishing. Acute and chronic toxicity were reduced by 90 and 81%, respectively. The largest CA and MN incidence in the meristematic cells of A. cepa were observed after exposure to the raw bleach plant effluent. The HAIB was able to reduce the acute and chronic toxicity as well as chromosome aberrations and the occurrence of micronucleus.

  16. Fracture resistance of bleached teeth restored with different procedures

    Directory of Open Access Journals (Sweden)

    Matheus Coelho Bandéca

    2012-08-01

    Full Text Available This study evaluated the fracture resistance of teeth submitted to internal bleaching and restored with different non-metallic post. Eighty mandibular incisors were endodontically treated and randomly divided in 10 groups (n = 8: G1- restored with composite resin (CR, G2- CR + fiber-reinforced composite post (FRC, Everstick post, Sticktech cemented with resin cement self-etch adhesive (RCS, Panavia F 2.0, Kuraray, G3- CR + FRC + self-adhesive resin cement (SRC, Breeze, Pentral Clinical, G4- CR+ glass fiber post (GF, Exacto Post, Angelus + RCS, G5- CR + GF + SRC. The G6 to G10 were bleached with hydrogen peroxide (HP and restored with the same restorative procedures used for G1 to G5, respectively. After 7 days storage in artificial saliva, the specimens were submitted to the compressive strength test (N at 0.5 mm/min cross-head speed and the failure pattern was identified as either reparable (failure showed until 2 mm below the cement-enamel junction or irreparable (the failure showed <2 mm or more below the cement-enamel. Data were analyzed by ANOVA and Tukey test (α = 0.05. No significant difference (p < 0.05 was found among G1 to G10. The results suggest that intracoronal bleaching did not significantly weaken the teeth and the failure patterns were predominately reparable for all groups. The non-metallic posts in these teeth did not improve fracture resistance.

  17. Peroxide dental bleaching via laser microchannels and tooth color measurements

    Science.gov (United States)

    Altshuler, Gregory; Belikov, Andrey; Skrypnik, Alexei; Feldchtein, Felix; Pushkareva, Alexandra; Shatilova, Ksenia; Cernavin, Igor; Tuchin, Valery

    2016-12-01

    The aim of this study was to use microchannels drilled by an Er:YAG laser into a human tooth through the enamel into the dentin for direct injection of hydrogen peroxide (HP) to produce a minimally invasive, rapid, tooth bleaching effect. The experiments were conducted in vitro. Five microchannels with a diameter of ˜200 μm and a depth of ˜2 mm were drilled through the palatal side of a human tooth crown using the microbeam of an Er:YAG-laser with a wavelength of 2.94 μm. After injection of an aqueous solution of 31%-HP through the microchannels, the tooth color was evaluated using a VITA shade guide and International Commission on Illumination L*ab color parameters. A tooth model used for the evaluation of the distribution of HP concentration was created and the amount of HP which can be injected into tooth dentin to bleach it safely was estimated. Injection of 1.5±0.1 mm3 of 31%-HP into the tooth led to noticeable bleaching within 3 h and significant improvement of tooth color within 24 h.

  18. Establishing Esri ArcGIS Enterprise Platform Capabilities to Support Response Activities of the NASA Earth Science Disasters Program

    Science.gov (United States)

    Molthan, A.; Seepersad, J.; Shute, J.; Carriere, L.; Duffy, D.; Tisdale, B.; Kirschbaum, D.; Green, D. S.; Schwizer, L.

    2017-12-01

    NASA's Earth Science Disasters Program promotes the use of Earth observations to improve the prediction of, preparation for, response to, and recovery from natural and technological disasters. NASA Earth observations and those of domestic and international partners are combined with in situ observations and models by NASA scientists and partners to develop products supporting disaster mitigation, response, and recovery activities among several end-user partners. These products are accompanied by training to ensure proper integration and use of these materials in their organizations. Many products are integrated along with other observations available from other sources in GIS-capable formats to improve situational awareness and response efforts before, during and after a disaster. Large volumes of NASA observations support the generation of disaster response products by NASA field center scientists, partners in academia, and other institutions. For example, a prediction of high streamflows and inundation from a NASA-supported model may provide spatial detail of flood extent that can be combined with GIS information on population density, infrastructure, and land value to facilitate a prediction of who will be affected, and the economic impact. To facilitate the sharing of these outputs in a common framework that can be easily ingested by downstream partners, the NASA Earth Science Disasters Program partnered with Esri and the NASA Center for Climate Simulation (NCCS) to establish a suite of Esri/ArcGIS services to support the dissemination of routine and event-specific products to end users. This capability has been demonstrated to key partners including the Federal Emergency Management Agency using a case-study example of Hurricane Matthew, and will also help to support future domestic and international disaster events. The Earth Science Disasters Program has also established a longer-term vision to leverage scientists' expertise in the development and delivery of

  19. Determination of rare earth elements concentration at different depth profile of Precambrian pegmatites using instrumental neutron activation analysis.

    Science.gov (United States)

    Sadiq Aliyu, Abubakar; Musa, Yahaya; Liman, M S; Abba, Habu T; Chaanda, Mohammed S; Ngene, Nnamani C; Garba, N N

    2018-01-01

    The Keffi area hosts abundant pegmatite bodies as a result of the surrounding granitic intrusions. Keffi is part of areas that are geologically classified as North Central Basement Complex. Data on the mineralogy and mineralogical zonation of the Keffi pegmatite are scanty. Hence the need to understand the geology and mineralogical zonation of Keffi pegmatites especially at different depth profiles is relevant as a study of the elemental composition of the pegmatite is essential for the estimation of its economic viability. Here, the relative standardization method of instrumental neutron activation analysis (INAA) has been used to investigate the vertical deviations of the elemental concentrations of rare earth elements (REEs) at different depth profile of Keffi pegmatite. This study adopted the following metrics in investigating the vertical variations of REEs concentrations. Namely, the total contents of rare earth elements (∑REE); ratio of light to heavy rare earth elements (LREE/HREE), which defines the enrichment or depletion of REEs; europium anomaly (Eu/Sm); La/Lu ratio relative to chondritic meteorites. The study showed no significant variations in the total content of rare elements between the vertical depth profiles (100-250m). However, higher total concentrations of REEs (~ 92.65ppm) were recorded at the upper depth of the pegmatite and the europium anomaly was consistently negative at all the depth profiles suggesting that the Keffi pegmatite is enriched with light REEs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. 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.

  1. Improving the hydrogen peroxide bleaching efficiency of aspen chemithermomechanical pulp by using chitosan.

    Science.gov (United States)

    Li, Zongquan; Dou, Hongyan; Fu, Yingjuan; Qin, Menghua

    2015-11-05

    The presence of transition metals during the hydrogen peroxide bleaching of pulp results in the decomposition of hydrogen peroxide, which decreases the bleaching efficiency. In this study, chitosans were used as peroxide stabilizer in the alkaline hydrogen peroxide bleaching of aspen chemithermomechanical pulp (CTMP). The results showed that the brightness of the bleached CTMP increased 1.5% ISO by addition of 0.1% chitosan with 95% degree of deacetylation during peroxide bleaching. Transition metals in the form of ions or metal colloid particles, such as iron, copper and manganese, could be adsorbed by chitosans. Chitosans could inhibit the decomposition of hydrogen peroxide catalyzed by different transition metals under alkaline conditions. The ability of chitosans to inhibit peroxide decomposition depended on the type of transition metals, chitosan concentration and degree of deacetylation applied. The addition of chitosan slightly reduced the concentration of the hydroxyl radical formed during the hydrogen peroxide bleaching of aspen CTMP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Bank security dye packs: synthesis, isolation, and characterization of chlorinated products of bleached 1-(methylamino)anthraquinone.

    Science.gov (United States)

    Egan, James M; Rickenbach, Michael; Mooney, Kim E; Palenik, Chris S; Golombeck, Rebecca; Mueller, Karl T

    2006-11-01

    Banknote evidence is often submitted after a suspect has attempted to disguise or remove red dye stain that has been released because of an anti-theft device that activates after banknotes have been unlawfully removed from bank premises. Three chlorinated compounds have been synthesized as forensic chemical standards to indicate bank security dye bleaching as a suspect's intentional method for masking a robbery involving dye pack release on banknotes. A novel, facile synthetic method to provide three chlorinated derivatives of 1-(methylamino)anthraquinone (MAAQ) is presented. The synthetic route involved Ultra Clorox bleach as the chlorine source, iron chloride as the catalyst, and MAAQ as the starting material and resulted in a three-component product mixture. Two mono-chlorinated isomers (2-chloro-1-(methylamino)anthraquinone and 4-chloro-1-(methylamino)anthraquinone) and one di-chlorinated compound (2,4-dichloro-1-(methylamino)anthraquinone) of the MAAQ parent molecule were detected by gas chromatography mass spectrometry (GC-MS), and subsequently isolated by liquid chromatography (LC) with postcolumn fraction collection. Although GC-MS is sensitive enough to detect all of the chlorinated products, it is not definitive enough to identify the structural isomers. Liquid-state nuclear magnetic resonance (NMR) spectroscopy was utilized to elucidate structurally the ortho- and para-mono-chlorinated isomers once enough material was properly isolated. A reaction mechanism involving iron is proposed to explain the presence of chlorinated MAAQ species on stolen banknotes after attempted bleaching.

  3. The mobile GeoBus outreach project: hands-on Earth and Mars activities for secondary schools in the UK

    Science.gov (United States)

    Robinson, Ruth; Pike, Charlotte; Roper, Kathryn

    2015-04-01

    GeoBus (www.geobus.org.uk) is an educational outreach project that was developed in 2012 by the Department of Earth and Environmental Sciences at the University of St Andrews, and it is sponsored jointly by industry and the UK Research Councils (NERC and EPSRC). The aims of GeoBus are to support the teaching of Earth Science in secondary schools by providing teaching resources that are not readily available to educators, to inspire young learners by incorporating new science research outcomes in teaching activities, and to provide a bridge between industry, higher education institutions, research councils and schools. Since its launch, GeoBus has visited over 160 different schools across the length and breadth of Scotland. Just under 35,000 pupils have been involved in practical hands-on Earth science learning activities since the project began in 2012, including many in remote and disadvantaged regions. The resources that GeoBus brings to schools include all the materials and equipment needed to run 50 - 80 minute workshops, and half- or whole-day Enterprise Challenges and field excursions. Workshops are aimed at a class of up to 30 pupils and topics include minerals, rocks, fossils, geological time, natural resources, climate change, volcanoes, earthquakes, and geological mapping. As with all GeoBus activities, the inclusion of equipment and technology otherwise unavailable to schools substantially increases the engagement of pupils in workshops. Field excursions are increasingly popular, as many teachers have little or no field trainng and feel unable to lead this type of activity. The excursions comprise half or full day sessions for up to 30 pupils and are tailored to cover the local geology or geomorphology. Enterprise Challenge are half or full day sessions for up to 100 pupils. Topics include "Journey to Mars", "Scotland's Rocks", "Drilling for Oil", and "Renewable Energy". Both of the energy Enterprise Challenges were designed to incorporates ideas and

  4. Durability of bleaching results achieved with 15% carbamide peroxide and 38% hydrogen peroxide in vitro.

    Science.gov (United States)

    Knösel, Michael; Reus, Monika; Rosenberger, Albert; Attin, Thomas; Ziebolz, Dirk

    2011-01-01

    The aim of this study was to assess the durability of bleaching results achieved with (1) 15% carbamide peroxide home bleaching and (2) 38% hydrogen peroxide in-office bleaching. A total of 231 extracted anterior teeth were randomly divided into three groups (n = 77 in each group) with comparable mean baseline L*-values (68.24 ± 0.8): a non-bleached control group A, a 15% carbamide peroxide group B (5 bleaching intervals of 8 hours), and a 38% hydrogen peroxide group C (3 intervals of 15 minutes). Durability of bleaching was assessed by comparing CIE-L*a*b* data after intervals of 2, 4, 12, and 26 weeks from baseline. Both bleaching regimes initially produced a highly significant increase in lightness parameter L*, with no significant difference between the respective bleaching regimes (B: 68.23 / 72.48; C: 68.32 / 73.25). Six months after starting the trial, L*-values for group B yielded no significant differences compared to baseline (69.55), whereas L*-values for group C were still significantly raised (69.91), despite a highly significant decrease when compared to initial bleaching results. In both treatment groups, there was a lasting response to bleaching in terms of CIE-a* and -b* value decreases. Results for both home- and in-practice regimes were found to be similar for about 12 weeks. However, in-office results were longer lasting, despite the shorter treatment intervals. Summarized bleaching effects, in terms of delta E values, revealed no significant differences between treatment groups and the control group after 6 months, indicating an abatement of the bleaching results achieved.

  5. Hands On Earth Science.

    Science.gov (United States)

    Weisgarber, Sherry L.; Van Doren, Lisa; Hackathorn, Merrianne; Hannibal, Joseph T.; Hansgen, Richard

    This publication is a collection of 13 hands-on activities that focus on earth science-related activities and involve students in learning about growing crystals, tectonics, fossils, rock and minerals, modeling Ohio geology, geologic time, determining true north, and constructing scale-models of the Earth-moon system. Each activity contains…

  6. Solar wind-driven ULF activity in Earth's inner radiation belt: Effects on trapped electrons

    Science.gov (United States)

    Urban, K. D.; Gerrard, A. J.; Lanzerotti, L. J.; Mitchell, D. G.

    2013-12-01

    We report that, before and during multi-banded energetic electron events observed at near-equatorial, low L-values in the Van Allen Probes RBSPICE electron flux data, ULF power is distributed quasi-uniformly across broad ULF ranges (e.g., 9-20 minutes) for hours at a time. Data are used from 40+ conjugate ground-based magnetometers within the L-shell range [1-2]. This finding of geomagnetic power levels is in contrast to previous conclusions from low Earth-orbit DEMETER spacecraft data that similar trapped particle structures result from power distributed quasi-monochromatically at some central period within this band. Though modeling results associated with previous claims reproduce the multi-band energy structure in the simulated electron flux data, the model hinges on the existence of a sole monochromatic wave whose power is distributed over a range of azimuthal wave numbers. Given that we find the magnetometer data from many sites to have power distributed quasi-uniformly over a broad ULF range, we note that it's possible to isolate a "quasi-monochromatic" ULF wave of one's choosing from such a spectrum given the right choice of a filter. We also show that the ribbed energy structures in the RBSPICE electron fluxes are highly associated with the Kp Index and solar wind data; specifically, the structures seem to be associated with the speed of the solar wind, and therefore with the passage of interplanetary structures past Earth.

  7. Effects of bleaching agents and Tooth Mousse(™) on human enamel hardness.

    Science.gov (United States)

    Alkhtib, Asmaa; Manton, David J; Burrow, Michael F; Saber-Samandari, Saeed; Palamara, Joseph E A; Gross, Kārlis A; Reynolds, Eric C

    2013-05-01

    The aim of this laboratory study was to investigate the effect of three commercial bleaching agents and Tooth Mousse(™) containing 10% w/w casein phosphopeptide-amorphous calcium phosphate on the hardness of tooth enamel. Sixteen human enamel specimens were exposed to one of three commercial bleaching agents with or without subsequent exposure to Tooth Mousse(™) . Nanoindentation was used to measure the hardness and reduced modulus before and after treatments. When bleaching materials were applied for a short period of time following the manufacturers' instructions, there was an increase in enamel hardness and reduced modulus for some bleaching groups, with no statistically significant difference from the baseline values. After extended bleaching periods a statistically significant decrease in enamel hardness and reduced modulus was found and after applying Tooth Mousse(™) post-bleaching, the hardness and reduced modulus returned to close to baseline values. The application of bleaching agents for an extended period of time significantly decreases enamel hardness and the reduced modulus. The application of Tooth Mousse(™) after bleaching was able to reestablish the baseline enamel hardness and reduced modulus, decreasing the adverse effects of bleaching enamel. © 2012 Wiley Publishing Asia Pty Ltd.

  8. Use of the LM-OSL technique for the detection of partial bleaching in quartz

    DEFF Research Database (Denmark)

    Larsen, N.A.; Bulur, E.; Bøtter-Jensen, L.

    2000-01-01

    is known as linear modulation OSL (LM-OSL). In controlled laboratory conditions, this technique has been employed to study the ease-of-bleaching of the trapped charge in quartz by comparing the OSL curves of quartz aliquots which have been either: (1) fully bleached, followed by a laboratory dose of beta...... -irradiation, or (2) partially bleached, followed by the laboratory beta -dose. The ratio of the OSL signals due to the beta -dose from the partly and fully bleached aliquots is illustrated to be a potential indicator of the degree of optical resetting of the OSL signal in dating material. The key parameter...

  9. 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......-office bleaching was progressively reversed by contact with saliva for 14 days. The whiteness index was not affected by contact with coffee during the remineralization period. CLINICAL SIGNIFICANCE: The results of this in situ study suggest that the mineral loss caused by in-office dental bleaching is minimal...

  10. Comparison of Flexural Strength of Resin Cements After Storing in Different Media and Bleaching Agents.

    Science.gov (United States)

    Geramipanah, Farideh; Rezaei, Susan Mir Mohammad; Jafary, Maryam; Sadighpour, Leyla

    2015-06-01

    The aim of this study was to determine the effects of different storage media and bleaching treatments on the flexural strength of two resin cements (Panavia and BisCem). One hundred rectangular-shaped specimens were prepared with two resin cements and were stored in five media types (n = 10): distilled water (DW), lactic acid (LA), sodium hydroxide (NH), in-office bleaching (OB) and home bleaching (HB). There was significant interaction between the solutions and cements (p except Panavia in OB) (p exception of in-office bleaching.

  11. A Study for Tooth Bleaching via Carbamide Peroxide-Loaded Hollow Calcium Phosphate Spheres

    Directory of Open Access Journals (Sweden)

    Tao Qin

    2016-12-01

    Full Text Available The objective of this study was to investigate if a prolonged bleaching effect of carbamide peroxide-loaded hollow calcium phosphate spheres (HCPS can be achieved. HCPS was synthesized via a hydrothermal reaction method. Carbamide peroxide (CP was-loaded into HCPS by mixing with distilled water as solvent. We developed two bleaching gels containing CP-loaded HCPS: one gel with low HP concentration as at-home bleaching gel, and one with high HP concentration as in-office gel. Their bleaching effects on stained human permanent posterior teeth were investigated by measuring the color difference before and after bleaching. The effect of gels on rhodamine B degradation was also studied. To investigate the potential effect of remineralization of using HCPS, bleached teeth were soaked in phosphate buffer solution (PBS containing calcium and magnesium ions. Both bleaching gels had a prolonged whitening effect, and showed a strong ability to degrade rhodamine B. After soaking in PBS for 3 days, remineralization was observed at the sites where HCPS attached to the teeth surface. CP-loaded HCPS could prolong the HP release behavior and improve the bleaching effect. HCPS was effective in increasing the whitening effect of carbamide peroxide and improving remineralization after bleaching process.

  12. 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.

  13. Space active optics sensing and control for earth observation at high angular resolution

    Science.gov (United States)

    Escolle, C.; Michau, V.; Ferrari, M.; Fusco, T.; Hugot, E.; Bret-Dibat, T.

    2017-11-01

    Discoveries in astronomy and earth science lie on the capabilities of the space observatories to see fainter objects and smaller details. This need of high collecting power and high angular resolution implies instruments with large primary mirrors. However, a simple scaling of existing space telescopes leads to bigger optical elements and structure that exceed the allocated volume and launch mass capability of medium size launchers. Due to volume, weight and cost constraints on satellites, the next generation of large telescopes must combine innovative and compact optical concepts using lightweight primary mirrors and structures. Furthermore the lightweighting of primary mirrors and structures reduce their stiffness and make them more deformable under static and dynamic load. Also, the compactness needed implies primary mirrors with low focal ratio and a small distance between primary and secondary mirrors. This leads to an optical train more sensitive to misalignment.

  14. Rare earth elements determination in medicinal plants by Neutron Activation Analisys

    International Nuclear Information System (INIS)

    Goncalves, Rodolfo D.M.R.; Francisconi, Lucilaine S.; Silva, Paulo S.C. da

    2013-01-01

    Rare Earth Elements (REEs) have been considered nontoxic for human health and for the environment; however, the use of REEs in the development of recent technologies has increased the interest un their biological effects. Some studies related to their concentration in foodstuffs were published but REEs levels in medicinal plants are still unknown. The objective of this study was to determine the Rees concentration in the set of 59 medicinal herbs commonly used by Brazilian folk. Results showed that plants can concentrate REEs in their aerial parts, but the amount transferred to the extract of these plants is relatively low, resulting in little ingestion of these elements by the population during the extract consumption. (author)

  15. 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.

  16. Active optics as enabling technology for future large missions: current developments for astronomy and Earth observation at ESA

    Science.gov (United States)

    Hallibert, Pascal

    2017-09-01

    In recent years, a trend for higher resolution has increased the entrance apertures of future optical payloads for both Astronomy and Earth Observation most demanding applications, resulting in new opto-mechanical challenges for future systems based on either monolithic or segmented large primary mirrors. Whether easing feasibility and schedule impact of tight manufacturing and integration constraints or correcting mission-critical in-orbit and commissioning effects, Active Optics constitutes an enabling technology for future large optical space instruments at ESA and needs to reach the necessary maturity in time for future mission selection and implementation. We present here a complete updated overview of our current R and D activities in this field, ranging from deformable space-compatible components to full correction chains including wavefront sensing as well as control and correction algorithms. We share as well our perspectives on the way-forward to technological maturity and implementation within future missions.

  17. Changes in coral-associated microbial communities during a bleaching event.

    Science.gov (United States)

    Bourne, David; Iida, Yuki; Uthicke, Sven; Smith-Keune, Carolyn

    2008-04-01

    Environmental stressors such as increased sea surface temperatures are well-known for contributing to coral bleaching; however, the effect of increased temperatures and subsequent bleaching on coral-associated microbial communities is poorly understood. Colonies of the hard coral Acropora millepora were tagged on a reef flat off Magnetic Island (Great Barrier Reef) and surveyed over 2.5 years, which included a severe bleaching event in January/February 2002. Daily average water temperatures exceeded the previous 10-year average by more than 1 degrees C for extended periods with field-based visual surveys recording all tagged colonies displaying signs of bleaching. During the bleaching period, direct counts of coral zooxanthellae densities decreased by approximately 64%, before recovery to pre-bleaching levels after the thermal stress event. A subset of three tagged coral colonies were sampled through the bleaching event and changes in the microbial community elucidated. Denaturing gradient gel electrophoresis (DGGE) analysis demonstrated conserved bacterial banding profiles between the three coral colonies, confirming previous studies highlighting specific microbial associations. As coral colonies bleached, the microbial community shifted and redundancy analysis (RDA) of DGGE banding patterns revealed a correlation of increasing temperature with the appearance of Vibrio-affiliated sequences. Interestingly, this shift to a Vibrio-dominated community commenced prior to visual signs of bleaching. Clone libraries hybridized with Vibrio-specific oligonucleotide probes confirmed an increase in the fraction of Vibrio-affiliated clones during the bleaching period. Post bleaching, the coral microbial associations again shifted, returning to a profile similar to the fingerprints prior to bleaching. This provided further evidence for corals selecting and shaping their microbial partners. For non-bleached samples, a close association with Spongiobacter-related sequences were

  18. Nanotribological and Nanomechanical Properties Changes of Tooth After Bleaching and Remineralization in Wet Environment

    Science.gov (United States)

    Yu, Dandan; Gao, Shanshan; Min, Jie; Zhang, Qianqian; Gao, Shuai; Yu, Haiyang

    2015-12-01

    Teeth bleaching cases had increased with people's desire for oral aesthetic; however, bleached teeth would still undertake chewing actions and remineralizing process in saliva. Nanotribological and nanomechanical properties are proper displays for dental performance of bleached teeth. The purpose of the research was to reveal the effect of bleaching and remineralization on the nanotribological and nanomechanical properties of teeth in wet environment. The specimens were divided into four groups according to the bleaching products used: 12 % hydrogen peroxide (HP) (12HP group); 15 % carbamide peroxide (CP) (15CP group); 35 % CP (35CP group); and artificial saliva (control group). The nanotribological and nanomechanical property changes of tooth enamel after bleaching and remineralization were evaluated respectively by nanoscratch and nanoindentation tests in wet environment, imitating the wet oral environment. The morphology changes were evaluated by statistical parametric mapping (SPM) and scanning electron microscopy (SEM). After bleaching, 12HP group and 15CP group showed increased scratch depth with more pile ups on the scratch edges, decreased nanohardness, and corroded surface appearance. While the 35CP group showed an increase in nanoscratch depth, no change in nanohardness and surface appearance was observed. The control group showed no change in these measurements. After remineralization, the three bleaching groups showed decreased nanoscratch depth and no change of nanohardness compared with the bleached teeth. And the control group showed no changes in nanotribological and nanomechanical properties. The nanotribological and nanomechanical properties of the 12HP group and 15CP group were affected by bleaching, but the nanotribological properties recovered partly and the nanomechanical properties got no change after 1 week of remineralization. As for the 35CP group, the nanotribological properties were influenced and the nanomechanical properties were not

  19. Contrasting patterns of coral bleaching susceptibility in 2010 suggest an adaptive response to thermal stress.

    Directory of Open Access Journals (Sweden)

    James R Guest

    Full Text Available BACKGROUND: Coral bleaching events vary in severity, however, to date, the hierarchy of susceptibility to bleaching among coral taxa has been consistent over a broad geographic range and among bleaching episodes. Here we examine the extent of spatial and temporal variation in thermal tolerance among scleractinian coral taxa and between locations during the 2010 thermally induced, large-scale bleaching event in South East Asia. METHODOLOGY/PRINCIPAL FINDINGS: Surveys to estimate the bleaching and mortality indices of coral genera were carried out at three locations with contrasting thermal and bleaching histories. Despite the magnitude of thermal stress being similar among locations in 2010, there was a remarkable contrast in the patterns of bleaching susceptibility. Comparisons of bleaching susceptibility within coral taxa and among locations revealed no significant differences between locations with similar thermal histories, but significant differences between locations with contrasting thermal histories (Friedman = 34.97; p<0.001. Bleaching was much less severe at locations that bleached during 1998, that had greater historical temperature variability and lower rates of warming. Remarkably, Acropora and Pocillopora, taxa that are typically highly susceptible, although among the most susceptible in Pulau Weh (Sumatra, Indonesia where respectively, 94% and 87% of colonies died, were among the least susceptible in Singapore, where only 5% and 12% of colonies died. CONCLUSIONS/SIGNIFICANCE: The pattern of susceptibility among coral genera documented here is unprecedented. A parsimonious explanation for these results is that coral populations that bleached during the last major warming event in 1998 have adapted and/or acclimatised to thermal stress. These data also lend support to the hypothesis that corals in regions subject to more variable temperature regimes are more resistant to thermal stress than those in less variable environments.

  20. T Cell Activation in Microgravity Compared to 1g (Earth s) Gravity

    Data.gov (United States)

    National Aeronautics and Space Administration — This study tested the hypothesis that transcription of immediate early genes is inhibited in T cells activated in microgravity (mg). Immunosuppression during...

  1. 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

    Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...

  2. Seismic imaging at the cross-roads: Active, passive, exploration and solid Earth

    Science.gov (United States)

    Rawlinson, N.; Stephenson, R.; Carbonell, R.

    2017-10-01

    Science has grown from our need to understand the world around us. Seismology is no different, with earthquakes and their destructive effect on society providing the motivation to understand the Earth's seismic wavefield. The question of when seismology as a science really began is an interesting one, but it is unlikely that there will ever be a universally agreed-upon date, partly because of the incompleteness of the historical record, and partly because the definition of what constitutes science varies from person to person. For instance, one could regard 1889 as the true birth of seismology, because that is when the first distant earthquake was detected by an instrument; in this case Ernst von Rebeur-Paschwitz detected an earthquake in Japan using a pendulum in Potsdam, Germany (Ben-Menahem, 1995). However, even the birth of instrumental seismology could be contested; the so-called Zhang Heng directional ;seismoscope; (detects ground motion but not as a function of time) was invented in 132 CE (Rui and Yan-xiang, 2006), and is said to have detected a four-hundred mile distant earthquake which was not felt at the location of the instrument (Needham, 1959; Dewey and Byerly, 1969). Prior to instrumental seismology, observations of earthquakes were not uncommon; for instance, Aristotle provided a classification of earthquakes based on the nature of observed ground motion (Ben-Menahem, 1995).

  3. Purification, characterization and thermostability improvement of xylanase from Bacillus amyloliquefaciens and its application in pre-bleaching of kraft pulp.

    Science.gov (United States)

    Kumar, Sharad; Haq, Izharul; Prakash, Jyoti; Singh, Sudheer Kumar; Mishra, Shivaker; Raj, Abhay

    2017-05-01

    Xylanases have important industrial applications but are most extensively utilized in the pulp and paper industry as a pre-bleaching agent. We characterized a xylanase from Bacillus amyloliquefaciens strain SK-3 and studied it for kraft pulp bleaching. The purified enzyme had a molecular weight of ~50 kDa with optimal activity at pH 9.0 and 50 °C. The enzyme showed good activity retention (85%) after 2 h incubation at 50 °C and pH 9.0. This enzyme obeyed Michaelis-Menten kinetics with regard to beechwood xylan with K m and V max values of 5.6 mg/ml, 433 μM/min/mg proteins, respectively. The enzyme activity was stimulated by Mn 2+ , Ca 2+ and Fe 2+ metal ions. Further, it also showed good tolerance to phenolics (2 mM) in the presence of syringic acid (no loss), cinnamic acid (97%), benzoic acid (94%) and phenol (97%) activity retention. The thermostability of xylanase was increased by 6.5-fold in presence of sorbitol (0.75 M). Further, pulp treated with 20U/g of xylanase (20IU/g) alone and with sorbitol (0.75M) reduced kappa number by 18.3 and 23.8%, respectively after 3 h reaction. In summary, presence of xylanase shows good pulp-bleaching activity, good tolerance to phenolics, lignin and metal ions and is amenable to thermostability improvement by addition of polyols. The SEM image showed significant changes on the surface of xylanase-treated pulp fiber as a result of xylan hydrolysis.

  4. Probing the nanoscale structure of the catalytically active overlayer on Pt alloys with rare earths

    DEFF Research Database (Denmark)

    Pedersen, Anders Filsøe; Ulrikkeholm, Elisabeth Therese; Escribano, Maria Escudero

    2016-01-01

    PtxY and PtxGd exhibit exceptionally high activity for oxygen reduction, both in the polycrystalline form and the nanoparticulate form. In order to understand the origin of the enhanced activity of these alloys, we have investigated thin films of these alloys on bulk Pt(111) crystals, i.e. Y/Pt(111...

  5. Bleaching augments lipid peroxidation products in pistachio oil and its cytotoxicity

    Science.gov (United States)

    Pistachio consumption is associated with reductions in serum cholesterol and oxidative stress due to their constituents of unsaturated fats, phytosterols, fiber, and antioxidants. Bleaching has been applied to whiten nut shells for antifungal and cosmetic purposes. However, the impact of bleaching o...

  6. Skin bleaching: A neglected form of injury and threat to global skin ...

    African Journals Online (AJOL)

    Skin bleaching: A neglected form of injury and threat to global skin. JC Street, K Gaska, KM Lewis, ML Wilson. Abstract. Skin bleaching is the use of creams, gels, or soaps to lighten the skin and is known to cause a number of injuries, many of which are potentially life-threatening. Despite the growing body of research ...

  7. Re-evaluating luminescence burial doses and bleaching of fluvial deposits using Bayesian computational statistics.

    NARCIS (Netherlands)

    Cunningham, A.C.; Wallinga, J.; Versendaal, Alice; Makaske, A.; Middelkoop, H.; Hobo, N.

    2015-01-01

    The optically stimulated luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  8. Re-evaluating luminescence burial doses and bleaching of fluvial deposits using Bayesian computational statistics

    NARCIS (Netherlands)

    Cunningham, A. C.; Wallinga, J.; Hobo, N.; Versendaal, A. J.; Makaske, B.; Middelkoop, H.

    2015-01-01

    The optically stimulated luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  9. WOOD BASIC DENSITY EFFECT OF Eucalyptus grandis x Eucalyptus urophylla CLONES ON BLEACHED PULP QUALITY

    Directory of Open Access Journals (Sweden)

    Sheila Rodrigues dos Santos

    2010-08-01

    Full Text Available The study analyzed the wood basic density effect in two Eucalyptus grandis x Eucalyptus urophylla hybrid clones (440 kg/m3 e 508 kg/m3 on bleached pulp quality (fiber dimensions and physical-mechanical properties. The woods performance on pulping, bleaching and beating results were analyzed. The Kraft pulping was carried out in forced circulation digester in order to obtain 17±1 kappa number targets. The pulps were bleached to 90±1 using delignification oxygen and D0EOPD1 bleaching sequence. Bleached pulp of low basic density clone showed, significantly, lowest revolutions number in the PFI mill to reach tensile index of 70 N.m/g, low Schopper Riegler degree and generated sheets with higher values to bulk and opacity. These characteristics and properties allow concluding that bleached pulp of low basic density clone was the most indicated to produce printing and writing sheets. The bleached pulp of high basic density clone showed higher values of bulk and capillarity Klemm and lower water retention value when analyzed without beating. The bleached pulp of high basic density clone showed more favorable characteristics to the production of tissue papers.

  10. Influence of photo- and thermal bleaching on pre-irradiation low water peak single mode fibers

    Science.gov (United States)

    Yin, Jianchong; Wen, Jianxiang; Luo, Wenyun; Xiao, Zhongyin; Chen, Zhenyi; Wang, Tingyun

    2011-12-01

    Reducing the radiation-induced transmission loss in low water peak single mode fiber (LWP SMF) has been investigated by using photo-bleaching method with 980nm pump light source and using thermal-bleaching method with temperature control system. The results show that the radiation-induced loss of pre-irradiation optical fiber can be reduced effectively with the help of photo-bleaching or thermal-bleaching. Although the effort of photo-bleaching is not as significant as thermal-bleaching, by using photo-bleaching method, the loss of fiber caused by radiation-induced defects can be reduced best up to 49% at 1310nm and 28% at 1550nm in low pre-irradiation condition, the coating of the fiber are not destroyed, and the rehabilitating time is just several hours, while self-annealing usually costs months' time. What's more, the typical high power LASER for photo-bleaching can be 980nm pump Laser Diode, which is very accessible.

  11. Remote Sensing of Coral Bleaching Using Temperature and Light: Progress towards an Operational Algorithm

    Directory of Open Access Journals (Sweden)

    William Skirving

    2017-12-01

    Full Text Available The National Oceanic and Atmospheric Administration’s Coral Reef Watch program developed and operates several global satellite products to monitor bleaching-level heat stress. While these products have a proven ability to predict the onset of most mass coral bleaching events, they occasionally miss events; inaccurately predict the severity of some mass coral bleaching events; or report false alarms. These products are based solely on temperature and yet coral bleaching is known to result from both temperature and light stress. This study presents a novel methodology (still under development, which combines temperature and light into a single measure of stress to predict the onset and severity of mass coral bleaching. We describe here the biological basis of the Light Stress Damage (LSD algorithm under development. Then by using empirical relationships derived in separate experiments conducted in mesocosm facilities in the Mexican Caribbean we parameterize the LSD algorithm and demonstrate that it is able to describe three past bleaching events from the Great Barrier Reef (GBR. For this limited example, the LSD algorithm was able to better predict differences in the severity of the three past GBR bleaching events, quantifying the contribution of light to reduce or exacerbate the impact of heat stress. The new Light Stress Damage algorithm we present here is potentially a significant step forward in the evolution of satellite-based bleaching products.

  12. Severity of the 1998 and 2005 bleaching events in Venezuela, southern Caribbean

    Directory of Open Access Journals (Sweden)

    Sebastián Rodríguez

    2010-10-01

    Full Text Available This study describes the severity of the 2005 bleaching event at 15 reef sites across Venezuela and compares the 1998 and 2005 bleaching events at one of them. During August and September 2005, bleached corals were first observed on oceanic reefs rather than coastal reefs, affecting 1 to 4% of coral colonies in the community (3 reef sites, n=736 colonies. At that time, however, no bleached corals were recorded along the eastern coast of Venezuela, an area of seasonal upwelling (3 reefs, n=181 colonies. On coastal reefs, bleaching started in October but highest levels were reached in November 2005 and January 2006, when 16% of corals were affected among a wide range of taxa (e.g. scleractinians, octocorals, Millepora and zoanthids. In the Acropora habitats of Los Roques (an oceanic reef, no bleached was recorded in 2005 (four sites, n=643 colonies. At Cayo Sombrero, a coastal reef site, bleaching was less severe in 1998 than in 2005 (9% of the coral colonies involving 2 species vs. 26% involving 23 species, respectively. Our results indicate that bleaching was more severe in 2005 than in 1998 on Venezuelan reefs; however, no mass mortality was observed in either of these two events. Rev. Biol. Trop. 58 (Suppl. 3: 189-196. Epub 2010 October 01.

  13. Severity of the 1998 and 2005 bleaching events in Venezuela, southern Caribbean.

    Science.gov (United States)

    Rodríguez, Sebastián; Cróquer, Aldo; Bone, David; Bastidas, Carolina

    2010-10-01

    This study describes the severity of the 2005 bleaching event at 15 reef sites across Venezuela and compares the 1998 and 2005 bleaching events at one of them. During August and September 2005, bleached corals were first observed on oceanic reefs rather than coastal reefs, affecting 1 to 4% of coral colonies in the community (3 reef sites, n = 736 colonies). At that time, however, no bleached corals were recorded along the eastern coast of Venezuela, an area of seasonal upwelling (3 reefs, n = 181 colonies). On coastal reefs, bleaching started in October but highest levels were reached in November 2005 and January 2006, when 16% of corals were affected among a wide range of taxa (e.g. scleractinians, octocorals, Millepora and zoanthids). In the Acropora habitats of Los Roques (an oceanic reef),no bleached was recorded in 2005 (four sites,n = 643 colonies). At Cayo Sombrero, a coastal reef site, bleaching was less severe in 1998 than in 2005 (9% of the coral colonies involving 2 species vs. 26% involving 23 species, respectively). Our results indicate that bleaching was more severe in 2005 than in 1998 on Venezuelan reefs; however, no mass mortality was observed in either of these two events.

  14. [Effect of bleaching agents on the color of indirect and direct composite resins].

    Science.gov (United States)

    Xing, Wenzhong; Jiang, Tao; Chen, Xiaodong; Wang, Yining

    2014-09-01

    To evaluate the effect of bleaching agents on the color of indirect and direct composite resins. Five resin composite materials were tested in this in vitro study. The five composites were as follow: two indirect composite resins (Adoro SR, Ceramage) and three direct composite resins (Filtek Z350, Clearfil Majesty Esthetic, and Gradia Direct Anterior). For each material, twenty disk-shaped specimens were prepared and randomly divided into five groups according to the color parameters of specimens before bleaching treatment. The composite resin specimens were treated by one of five sample solutions which were at-home bleaching agents (10% and 15% carbarmide peroxide), in- office bleaching agents (38% H(2)O(2) and 35%H(2)O(2)) and deionized water (control group). The color parameters of specimens were measured by spectrophotometer at baseline and after bleaching treatments. The color differences (ΔE values) between baseline and post-treatments were calculated. The data of color differences were evaluated statistically using two-way analysis with a significance level of 0.05. The color changes of the resin composites were less than 2.0 after bleaching agent treatment, therefore were not perceptible. Slight increase of L(*) values and decrease of C(*)ab values in color parameters of specimens were observed. There were statistically significant differences in ΔE values for different bleaching treatments and resin materials (P = 0.001). The bleaching agents did not affect the color of indirect and direct composite resins tested.

  15. Comparing Environmental Influences on Coral Bleaching Across and within Species using Clustered Binomial Regression

    Science.gov (United States)

    Differential susceptibility among reef-building coral species can lead to community shifts and loss of diversity as a result of temperature-induced mass bleaching events. However, the influence of the local environment on species-specific bleaching susceptibilities has not been ...

  16. 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.

  17. Effect of nightguard vital bleaching gel on the color stability of provisional restorative materials.

    Science.gov (United States)

    Bajunaid, Salwa Omar

    2016-01-01

    To assess the hypothesis that there was no difference in effect of 10% and 15% tooth bleaching agents on color stability of materials used for provisional fixed dental prosthesis. Fifteen samples from two materials used for provisional fixed dental prosthesis: methacrylate-based and composite-based materials and 15 preformed polycarbonate crowns soaked in bleaching gel or distilled water. Spectrophotometer recorded color of specimens at baseline, after 3, 7, and 14 days. Data were statistically analyzed using two-factor ANOVA test to compare the color stability of tested materials. Methyl-based provisional material exhibited statistically higher color change when exposed to 10% and 15% bleaching gel (delta EFNx01: 9.0 and 11.1, respectively) as compared to distilled water (delta EFNx01: 2.9). Delta EFNx01 of composite-based material specimens exposed to distilled water was statistically higher (6.3) than specimens exposed to 10% and 15% bleaching gel (1.5 and 1.1, respectively). Polycarbonate crowns showed a statistically lower color change when exposed to 15% (0.9) than to 10% bleaching gel (5.1) or distilled water (5.5). 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.

  18. National Institute of Research and Development for Earth Physics, Bucharest: 25 Years of activity

    International Nuclear Information System (INIS)

    Marmureanu, Gh.

    2002-01-01

    The experimental research in Earth Physics has a tradition of over one century in Romania, the first seismological station and the first magnetic map of the country (1892) being the work of Stefan Hepites, member of the Romanian Academy. Hepites made the first systematic macroseismic observations as earlier as 1892. These results were obtained within the meteorological network that in 1901 was operating 400 stations all over the country. The first seismic instruments were installed in Romania at Bucharest in 1895 and were a microseismoscop Guzzanti and a Tacchini pendulum. In 1904 the Kingdom of Romania adhered at International Association of Seismology and Stefan Hepites was appointed in the Permanent Commission of Seismology. The beginning of the 20th century marked the setting up of Timisoara station in 1904. The station of substantially improved in 1943 by prof. Ion Curea who installed two horizontal mechanical pendulums of 540 Kg. After an interruption between 1944 and 1950 this station has been operated continuously until the present time. The Romanian seismological service was founded in January 1, 1935 under the leader ship of prof. G. Demetrescu in the framework of the Seismic Observatory of Bucharest. The seismic network consisting of 2 stations (at Bucharest and Cernauti) in 1936, was extended to 5 more stations after the occurrence of the strong earthquake of 1940 (45.8 angle N, 26.7 angle E, h =150 Km, M w = 7.7) at Focsani, Bacau, Campu Lung, Iasi and Vrancioaia. In his study, Demetrescu evidenced the present of a persistent and isolated seismic focus characterized by deep earthquake localized beneath the Carpathians are bend, in the Vrancea region. The second stronger earthquake in modern time was that of 1977. A radio-telemetric array of 15 seismic stations was installed with PNUD - UNESCO support. In 1977 the National Institute for Earth Physics (NIEP) was founded. Its main tasks are: 1. Monitoring of seismicity (Operation and maintenance of the

  19. The Earth Resources Observation Systems data center's training technical assistance, and applications research activities

    Science.gov (United States)

    Sturdevant, J.A.

    1981-01-01

    The Earth Resources Observation Systems (EROS) Data Center (EDO, administered by the U.S. Geological Survey, U.S. Department of the Interior, provides remotely sensed data to the user community and offers a variety of professional services to further the understanding and use of remote sensing technology. EDC reproduces and sells photographic and electronic copies of satellite images of areas throughout the world. Other products include aerial photographs collected by 16 organizations, including the U.S. Geological Survey and the National Aeronautics and Space Administration. Primary users of the remotely sensed data are Federal, State, and municipal government agencies, universities, foreign nations, and private industries. The professional services available at EDC are primarily directed at integrating satellite and aircraft remote sensing technology into the programs of the Department of the Interior and its cooperators. This is accomplished through formal training workshops, user assistance, cooperative demonstration projects, and access to equipment and capabilities in an advanced data analysis laboratory. In addition, other Federal agencies, State and local governments, universities, and the general public can get assistance from the EDC Staff. Since 1973, EDC has contributed to the accelerating growth in development and operational use of remotely sensed data for land resource problems through its role as educator and by conducting basic and applied remote sensing applications research. As remote sensing technology continues to evolve, EDC will continue to respond to the increasing demand for timely information on remote sensing applications. Questions most often asked about EDC's research and training programs include: Who may attend an EDC remote sensing training course? Specifically, what is taught? Who may cooperate with EDC on remote sensing projects? Are interpretation services provided on a service basis? This report attempts to define the goals and

  20. Bioconstructor Guild Analysis to Assess Maldivian Reefs Following Ocean Warming and Coral Bleaching

    Science.gov (United States)

    Bianchi, C. N.; Morri, C.; Montefalcone, M.

    2016-02-01

    Extreme climatic anomalies related to global warming have triggered coral bleaching events across most tropical regions. The hot wave of 1998 El Niño caused mass coral mortality throughout the Indian Ocean. The Maldives has been among the most affected countries, with 60-100% coral mortality reported. Hard coral cover, which dropped to less than 10% after the bleaching, returned to pre-bleaching values of around 50% only by 2014. Between 1997 and 2015, we evaluated the change in cover on Maldivian reef flats of different bioconstructor guilds: i) primary builders are those organisms that build the reef framework and therefore assure reef aggradation; ii) secondary builders provide calcareous material to fill in the frame; iii) binders are encrusters that consolidate the reef edifice; iv) bafflers are soft-bodied algae and colonial invertebrates that, although not actively participating in the bioconstruction, help retaining sediment; v) abiotic attributes (rock, rubble, sand) evidently do not give any contribution to the bioconstruction. A bioconstruction potential index (BCP) was devised using the following formula: BCP = Σin (siCi%) × 100-1where, n is the number of bioconstructor guilds (5, in this case), si is an importance score assigned to the ith guild, and Ci% is the cover of the ith guild. In this study, the value of si has been established at 3 for the primary builders, 2 for the secondary builders, 1 for the binders, 0 for the bafflers, and -1 for the abiotic attributes. Therefore, BCP ranges theoretically from 3, in the unrealistic case of 100% cover by primary constructors, to -1, when only abiotic attributes are present and no bioconstruction is possible, the reef thus being prone to erosion and drowning. When applied to the Maldives data, BCP provided clear threshold values to evaluate constructional capacity. Negative values characterised Maldivian reefs between 1999 and 2003-3007. Values between 0 and 1 depict reefs capable of constratal growth

  1. Effect of Dispersion and Bleaching on the Mechanical and Optical Properties of Deinked Recycled Pulp

    Directory of Open Access Journals (Sweden)

    yahya hamzeh

    2016-06-01

    Full Text Available In this study the effects of oxidative bleaching and mechanical dispersion in different conditions on the optical and mechanical properties of deinked recycled pulp was investigated. Industrial deinked pulp was treated in the different conditions, including dispersion, combined oxidative bleaching during dispersion, and separate dispersion and then oxidative bleaching. Handsheet papers were made from obtained pulps and then scanned and taken photos were analyzed by Digimizer software, version 4.1.1.0 to analysis spot content. Optical and mechanical properties of obtained handsheets were determined and compared. Results indicated that mechanical dispersion decreased spot content and brightness and increased yellowing of the handsheets. Moreover, mechanical dispersion increased dry and wet tensile and burst strengths, water retention value (WRV, ash content and decreased tear strength of handsheet papers. This study revealed that combined dispersing and oxidative bleaching of de-inked pulp provided superior results in comparison to the separate dispersing and oxidative bleaching.

  2. 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.

  3. Spatial and temporal patterns of mass bleaching of corals in the Anthropocene

    KAUST Repository

    Hughes, Terry P.

    2018-01-16

    Tropical reef systems are transitioning to a new era in which the interval between recurrent bouts of coral bleaching is too short for a full recovery of mature assemblages. We analyzed bleaching records at 100 globally distributed reef locations from 1980 to 2016. The median return time between pairs of severe bleaching events has diminished steadily since 1980 and is now only 6 years. As global warming has progressed, tropical sea surface temperatures are warmer now during current La Nina conditions than they were during El Nino events three decades ago. Consequently, as we transition to the Anthropocene, coral bleaching is occurring more frequently in all El Nino-Southern Oscillation phases, increasing the likelihood of annual bleaching in the coming decades.

  4. The role of bleaching in pulp mill effluent effects on fish

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, J.; Hodson, P.; Cross, T. [Queen`s Univ., School of Environmental Studies, Queen`s Univ., Kingston, ON (Canada); Van Heiningen, A. [New Brunswick Univ., Limerick Pulp and Paper Centre, Fredericton, NB (Canada)

    1999-05-01

    Sources and potency of mixed function oxygenase (MFO)-inducing compounds within a 5-stage chlorine dioxide bleaching sequence at a pulp and paper mill was determined. Environmental concerns regarding chlorinated organic materials and their toxicity to aquatic organisms caused many mills to switch to elemental chlorine-free bleaching processes, with the most common being the chlorine dioxide bleaching process. However, even with this switch, effluent from kraft pulp mills still affect aquatic organisms. In this study, bleach plant filtrates were collected from two kraft mills in Ontario. The filtrates were used in fish bioassays to assess MFO-inducing potency. Results showed that potency varied depending on the wood used (softwood or hardwood) and the bleaching stage. Filtrates produced in a lab were weak MFO inducers compared to mill filtrates.14 refs., 6 figs.

  5. Climate change disables coral bleaching protection on the Great Barrier Reef.

    Science.gov (United States)

    Ainsworth, Tracy D; Heron, Scott F; Ortiz, Juan Carlos; Mumby, Peter J; Grech, Alana; Ogawa, Daisie; Eakin, C Mark; Leggat, William

    2016-04-15

    Coral bleaching events threaten the sustainability of the Great Barrier Reef (GBR). Here we show that bleaching events of the past three decades have been mitigated by induced thermal tolerance of reef-building corals, and this protective mechanism is likely to be lost under near-future climate change scenarios. We show that 75% of past thermal stress events have been characterized by a temperature trajectory that subjects corals to a protective, sub-bleaching stress, before reaching temperatures that cause bleaching. Such conditions confer thermal tolerance, decreasing coral cell mortality and symbiont loss during bleaching by over 50%. We find that near-future increases in local temperature of as little as 0.5°C result in this protective mechanism being lost, which may increase the rate of degradation of the GBR. Copyright © 2016, American Association for the Advancement of Science.

  6. Seasonal Dynamical Prediction of Coral Bleaching in the Great Barrier Reef, Australia

    Science.gov (United States)

    Spillman, C. M.; Alves, O.

    2009-05-01

    Sea surface temperature (SST) is now recognised as the primary cause of mass coral bleaching events. Coral bleaching occurs during times of stress, particularly when SSTs exceed the coral colony's tolerance level. Global warming is potentially a serious threat to the future of the world's reef systems with predictions by the international community that bleaching will increase in both frequency and severity. Advance warning of anomalous sea surface temperatures, and thus potential bleaching events, would allow for the implementation of management strategies to minimise reef damage. Seasonal SST forecasts from the coupled ocean-atmosphere model POAMA (Bureau of Meteorology) have skill in the Great Barrier Reef (Australia) several months into the future. We will present model forecasts and probabilistic products for use in reef management, and assess model skill in the region. These products will revolutionise the way in which coral bleaching events are monitored and assessed in the Great Barrier Reef and Australian region.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Radiochemical neutron-activation analysis of uncertified ultra-trace rare earth elements in two biological certified reference materials

    International Nuclear Information System (INIS)

    Cao, Lei; Tian, Weizhi; Ni, Bangfa; Wang, Pingsheng; Zhang, Yangmei

    2002-01-01

    Radiochemical neutron activation analysis (RNAA) has been used for the determination of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in two Chinese certified reference materials (CRM), GBW 08503 (wheat powder) and GBW 09101 (human hair). These determinations are important for possible certification of the above mentioned ultra-trace elements, so far not certified. A simple one-step (REE)F 3 precipitation was used. Chemical yields were determined for all relevant elements by means of tracer experiments. The two CRM were also analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to compare the merits and drawbacks of these two major trace analytical techniques for these particular elements. RNAA was proven to be a reliable technique for ultra-trace analysis, especially in the certification of some ultra-trace elements. (orig.)

  9. Effects of hydrogen peroxide bleaching strip gels on dental restorative materials in vitro: surface microhardness and surface morphology.

    Science.gov (United States)

    Duschner, Heinz; Götz, Hermann; White, Donald J; Kozak, Kathleen M; Zoladz, James R

    2004-01-01

    This study examined the effects of peroxide tooth bleaching, including Crest Whitestrips hydrogen peroxide gel treatments, on the surface hardness and morphology of common dental restorative treatments. American Dental Association (ADA) recommended dental restorative materials, including amalgam, dental gold, porcelain, glass ionomer, and composites, were prepared according to manufacturers' instructions. A cycling treatment methodology was employed which alternated ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching treatments included commercial Crest Whitestrips bleaching gels, which utilize hydrogen peroxide as the in situ bleaching source, and several commercial carbamide peroxide bleaching gels. Control treatments included placebo gels and an untreated group. Crest Whitestrips bleaching included treatment exposures simulating recommended clinical exposures (14 hours), along with excess bleaching simulating exposure to five times suggested Crest Whitestrips use. At the conclusion of treatments, surface microhardness measures and surface morphological assessments with standard and variable pressure (VP-) SEMs were conducted to assess the effects of bleaching exposure on the surface morphology and structural integrity of the restoratives. Surface microhardness and SEM measures revealed no significant deleterious effects on the restoration surfaces from Whitestrips gels. These results confirm that tooth bleaching from the selected commercial hydrogen peroxide or carbamide peroxide bleaching systems does not produce changes in surface morphology or microhardness of common dental restorative materials. These results support the clinical safety of the selected commercial bleaching systems to the oral environment, matching results obtained from long-term use of these ingredients applied in dental offices and available in commercial formulations.

  10. 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...

  11. 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...

  12. Fracture resistance of endodontically-treated teeth: effect of combination bleaching and an antioxidant.

    Science.gov (United States)

    Khoroushi, Maryam; Feiz, Atieh; Khodamoradi, Roghayeh

    2010-01-01

    This in vitro study assessed the fracture resistance of endodontically-treated teeth undergoing combination bleaching with 38% and 9.5% hydrogen peroxide gels as in-office and at-home bleaching techniques, respectively. In addition, the effect of an antioxidizing agent, sodium ascorbate, was investigated. Sixty maxillary premolars were endodontically-treated, received a glass ionomer barrier as a mechanical seal and were embedded in acrylic resin up to the cemento-enamel junction. The specimens were divided into four groups (n = 15) as follows: G I: no bleaching, access cavity restored with resin composite (negative control); G II: bleached for three weeks daily using 9.5% hydrogen peroxide for two hours and three sessions of in-office bleaching using 38% hydrogen peroxide every seven days, then restored (positive control); G III: bleached similar to G II and restored after one week; G IV: bleached similar to G II, along with the use of an antioxidizing agent for 24 hours, then restored. In each in-office and at-home bleaching session, the whitening gels were applied to the buccal surface of the tooth and placed inside the pulp chamber (inside/outside bleaching technique). Finally, the specimens underwent fracture resistance testing; the data were analyzed using ANOVA and Scheffé's test (alpha = 0.05). Significant differences were observed among the study groups (p 0.05). Within the limitations of the current study, it can be concluded that the fracture resistance of endodontically-treated teeth decreases after combination bleaching. The use of sodium ascorbate can reverse decreased fracture resistance.

  13. Urban forms, physical activity and body mass index: a cross-city examination using ISS Earth Observation photographs

    Science.gov (United States)

    Lin, Ge

    2005-01-01

    Johnson Space Center has archived thousands of astronauts acquired Earth images. Some spectacular images have been widely used in news media and in k-12 class room, but their potential utilizations in health promotion and disease prevention have relatively untapped. The project uses daytime ISS photographs to define city forms and links them to city or metropolitan level health data in a multicity context. Road connectivity, landuse mix and Shannon's information indices were used in the classification of photographs. In contrast to previous remote-sensing studies, which tend to focus on a single city or a portion of a city, this project utilized photographs of 39 U.S. cities. And in contrast to previous health-promotion studies on the built environment, which tend to rely on survey respondents' responses to evaluate road connectivity or mixed land use for a single study site, the project examined the built environments of multiple cities based on ISS photos. It was found that road connectivity and landuse mix were not statistically significant by themselves, but the composite measure of the Shannon index was significantly associated with physical activity, but not BMI. Consequently, leisure-time physical activity seems to be positively associated with the urban complexity scale. It was also concluded that unless they are planned or designed in advance, photographs taken by astronauts generally are not appropriate for a study of a single-site built environment nor are they appropriate for a study of infectious diseases at a local scale. To link urban built environment with city-wide health indicators, both the traditional nadir view and oblique views should be emphasized in future astronauts' earth observation photographs.

  14. "Sustainability on Earth" Webquests: Do They Qualify as Problem-Based Learning Activities?

    Science.gov (United States)

    Leite, Laurinda; Dourado, Luís; Morgado, Sofia

    2015-01-01

    Information and communication technologies (ICT), namely the Internet, can play a valuable educational role in several school subjects, including science education. The same applies to problem-based learning (PBL), that is, a student-centered active learning methodology that can prepare students for lifelong learning. WebQuests (WQs) combine PBL…

  15. Molybdenum phosphosulfide: an active, acid-stable, earth-abundant catalyst for the hydrogen evolution reaction.

    Science.gov (United States)

    Kibsgaard, Jakob; Jaramillo, Thomas F

    2014-12-22

    Introducing sulfur into the surface of molybdenum phosphide (MoP) produces a molybdenum phosphosulfide (MoP|S) catalyst with superb activity and stability for the hydrogen evolution reaction (HER) in acidic environments. The MoP|S catalyst reported herein exhibits one of the highest HER activities of any non-noble-metal electrocatalyst investigated in strong acid, while remaining perfectly stable in accelerated durability testing. Whereas mixed-metal alloy catalysts are well-known, MoP|S represents a more uncommon mixed-anion catalyst where synergistic effects between sulfur and phosphorus produce a high-surface-area electrode that is more active than those based on either the pure sulfide or the pure phosphide. The extraordinarily high activity and stability of this catalyst open up avenues to replace platinum in technologies relevant to renewable energies, such as proton exchange membrane (PEM) electrolyzers and solar photoelectrochemical (PEC) water-splitting cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Spatial representation of organic carbon and active-layer thickness of high latitude soils in CMIP5 earth system models

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Umakant; Drewniak, Beth; Jastrow, Julie D.; Matamala, Roser M.; Vitharana, U. W. A.

    2017-08-01

    Soil properties such as soil organic carbon (SOC) stocks and active-layer thickness are used in earth system models (F.SMs) to predict anthropogenic and climatic impacts on soil carbon dynamics, future changes in atmospheric greenhouse gas concentrations, and associated climate changes in the permafrost regions. Accurate representation of spatial and vertical distribution of these soil properties in ESMs is a prerequisite for redudng existing uncertainty in predicting carbon-climate feedbacks. We compared the spatial representation of SOC stocks and active-layer thicknesses predicted by the coupled Modellntercomparison Project Phase 5 { CMIP5) ESMs with those predicted from geospatial predictions, based on observation data for the state of Alaska, USA. For the geospatial modeling. we used soil profile observations {585 for SOC stocks and 153 for active-layer thickness) and environmental variables (climate, topography, land cover, and surficial geology types) and generated fine-resolution (50-m spatial resolution) predictions of SOC stocks (to 1-m depth) and active-layer thickness across Alaska. We found large inter-quartile range (2.5-5.5 m) in predicted active-layer thickness of CMIP5 modeled results and small inter-quartile range (11.5-22 kg m-2) in predicted SOC stocks. The spatial coefficient of variability of active-layer thickness and SOC stocks were lower in CMIP5 predictions compared to our geospatial estimates when gridded at similar spatial resolutions (24.7 compared to 30% and 29 compared to 38%, respectively). However, prediction errors. when calculated for independent validation sites, were several times larger in ESM predictions compared to geospatial predictions. Primaly factors leading to observed differences were ( 1) lack of spatial heterogeneity in ESM predictions, (2) differences in assumptions concerning environmental controls, and (3) the absence of pedogenic processes in ESM model structures. Our results suggest that efforts to incorporate

  17. A Study of Oceans and Atmospheric Interactions Associated with Tropical Cyclone Activity using Earth Observing Technology

    Science.gov (United States)

    Abdullah, Warith; Reddy, Remata

    From October 22nd to 30th, 2012 Hurricane Sandy was a huge storm of many abnormalities causing an estimated 50 billion dollars in damage. Tropical storm development states systems’ energy as product of warm sea surface temperatures (SST’s) and tropical cyclone heat potential (TCHP). Advances in Earth Observing (EO) technology, remote sensing and proxy remote sensing have allowed for accurate measurements of SST and TCHP information. In this study, we investigated rapid intensification of Sandy through EO applications for precipitable water vapor (PWAT), SST’s and TCHP during the period of October 27th. These data were obtained from NASA and NOAA satellites and NOAA National Buoy data center (NDBC). The Sensible Heat (Qs) fluxes were computed to determine available energy resulting from ocean-atmosphere interface. Buoy 41010, 120 NM east of Cape Canaveral at 0850 UTC measured 22.3 °C atmospheric temperatures and 27 °C SST, an interface of 4.7 °C. Sensible heat equation computed fluxes of 43.7 W/m2 at 982.0 mb central pressure. Sandy formed as late-season storm and near-surface air temperatures averaged > 21 °C according to NOAA/ESRL NCEP/NCAR reanalysis at 1000 mb and GOES 13 (EAST) geostationary water vapor imagery shows approaching cold front during October 27th. Sandy encountered massive dry air intrusion to S, SE and E quadrants of storm while travelling up U.S east coast but experienced no weakening. Cool, dry air intrusion was considered for PWAT investigation from closest sounding station during Oct. 27th 0900 - 2100 UTC at Charleston, SC station 72208. Measured PWAT totaled 42.97 mm, indicating large energy potential supply to the storm. The Gulf Stream was observed using NASA Short-term Prediction Research and Transition Center (SPoRT) MODIS SST analysis. The results show 5 °C warmer above average than surrounding cooler water, with > 25 °C water extent approximately 400 NM east of Chesapeake Bay and eddies > 26 °C. Results from sensible heat

  18. Changes in biologically-active ultraviolet radiation reaching the Earth's surface.

    Science.gov (United States)

    McKenzie, R L; Aucamp, P J; Bais, A F; Björn, L O; Ilyas, M

    2007-03-01

    patterns. The changes can be in both directions: ozone changes can affect climate, and climate change can affect ozone. The observational evidence suggests that stratospheric ozone (and therefore UV-B) has responded relatively quickly to changes in ozone-depleting substances, implying that climate interactions have not delayed this process. Model calculations predict that at mid-latitudes a return of ozone to pre-1980 levels is expected by the mid 21st century. However, it may take a decade or two longer in polar regions. Climate change can also affect UV radiation through changes in cloudiness and albedo, without involving ozone and since temperature changes over the 21st century are likely to be about 5 times greater than in the past century. This is likely to have significant effects on future cloud, aerosol and surface reflectivity. Consequently, unless strong mitigation measures are undertaken with respect to climate change, profound effects on the biosphere and on the solar UV radiation received at the Earth's surface can be anticipated. The future remains uncertain. Ozone is expected to increase slowly over the decades ahead, but it is not known whether ozone will return to higher levels, or lower levels, than those present prior to the onset of ozone depletion in the 1970s. There is even greater uncertainty about future UV radiation, since it will be additionally influenced by changes in aerosols and clouds.

  19. Predictions of lithium interactions with earth's bow shock in the presence of wave activity

    Science.gov (United States)

    Decker, R. B.; Lui, A. T. Y.; Vlahos, L.

    1984-01-01

    The results of a test-particle simulation studying the movement of a lithium tracer ion injected upstream of the bow shock are reported. Wave activity consists of parallel and antiparallel propagating Alfven waves characterized by a frequency power spectrum within a frequency or range of amplitudes defined separately in the upstream and downstream regions. The results show that even a moderate level of wave activity can substantially change the results obtained in the absence of waves. Among the effects observed are: (1) increased ion transmission; (2) both the average energy gain and spread about the average are increased for transmitted and reflected particles; (3) the average final pitch angle for transmitted particles tends to 90 deg, and the spread of reflected particles is reduced; and (4) the spatial dispersion of the ions on the bow shock after a single encounter is increased.

  20. Exploration of earth-abundant transition metals (Fe, Co, and Ni) as catalysts in unreactive chemical bond activations.

    Science.gov (United States)

    Su, Bo; Cao, Zhi-Chao; Shi, Zhang-Jie

    2015-03-17

    Activation of inert chemical bonds, such as C-H, C-O, C-C, and so on, is a very important area, to which has been drawn much attention by chemists for a long time and which is viewed as one of the most ideal ways to produce valuable chemicals. Under modern chemical bond activation logic, many conventionally viewed "inert" chemical bonds that were intact under traditional conditions can be reconsidered as novel functionalities, which not only avoids the tedious synthetic procedures for prefunctionalizations and the emission of undesirable wastes but also inspires chemists to create novel synthetic strategies in completely different manners. Although activation of "inert" chemical bonds using stoichiometric amounts of transition metals has been reported in the past, much more attractive and challenging catalytic transformations began to blossom decades ago. Compared with the broad application of late and noble transition metals in this field, the earth-abundant first-row transition-metals, such as Fe, Co, and Ni, have become much more attractive, due to their obvious advantages, including high abundance on earth, low price, low or no toxicity, and unique catalytic characteristics. In this Account, we summarize our recent efforts toward Fe, Co, and Ni catalyzed "inert" chemical bond activation. Our research first unveiled the unique catalytic ability of iron catalysts in C-O bond activation of both carboxylates and benzyl alcohols in the presence of Grignard reagents. The benzylic C-H functionalization was also developed via Fe catalysis with different nucleophiles, including both electron-rich arenes and 1-aryl-vinyl acetates. Cobalt catalysts also showed their uniqueness in both aromatic C-H activation and C-O activation in the presence of Grignard reagents. We reported the first cobalt-catalyzed sp(2) C-H activation/arylation and alkylation of benzo[h]quinoline and phenylpyridine, in which a new catalytic pathway via an oxidative addition process was demonstrated

  1. New approaches to evaluate sympathoadrenal system activity in experiments on Earth and in space

    Science.gov (United States)

    Kvetnansky, R.; Noskov, V. B.; Blazicek, P.; Macho, L.; Grigoriev, A. I.; Goldstein, D. S.; Kopin, I. J.

    In previous studies the activity of the sympathoadrenal system (SAS) in cosmonauts during space flights was evaluated by measuring plasma catecholamines (CA) levels and urinary CA and their metabolites concentrations. Plasma CA levels are accepted indicators of SAS activity, however, they are determined by the plasma clearances as well as the rates of CA release (spillover-SO) into the bloodstream. Nowadays methods are available which evaluate not only plasma levels of CA but also their release, spillover, uptake, reuptake, degradation and also CA synthesis in vivo measured by plasma levels of dihydroxyphenylalanine (DOPA). Plasma concentrations of DOPA, the CA noradrenaline (NE), adrenaline (ADR), and dopamine (DA), the deaminated catechol metabolites dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC), and the O-methylated metabolites methoxyhydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were measured during immobilization stress (IMO) in conscious rats. Radiotracer methods were used to measure NE SO. IMO markedly increased arterial NE levels but NE SO was less elevated bacause the NE clearance was slightly reduced in IMO rats. Simultaneous measurements of plasma CA and their metabolites provide another means to obtain information about SAS function. For instance, dissociation between changes of plasma DHPG and NE levels can indicate changes in neuronal reuptake of NE. We found marked parallel increases in plasma NE and DHPG levels during acute IMO; however after repeated IMO, plasma NE levels were increased but DHPG responses were less pronounced suggesting a reduced NE reuptake. DOPA, the CA precursor, circulates in plasma at a concentration higher than NE. During stress, increased sympathoneural outflow stimulates DOPA synthesis and release into the circulation supporting the view that changes in plasma DOPA levels during stress reflect in vivo changes in the rate of CA synthesis. We propose to measure the new plasma indicators of SAS

  2. Enhancing Earth Science And IT Literacy Through Environmental Science Information Technology Activities

    Science.gov (United States)

    Cuff, K. E.; Molinaro, M.

    2004-12-01

    The Environmental Science Information Technology Activities (ESITA) program provides grades 9 and 10 students with under-represented minority backgrounds in the East San Francisco Bay Area with real-world opportunities to learn about and apply information technologies through a series of project-based activities related to environmental science. Supported by the NSF Information Technology Experiences for Students and Teachers (ITEST) program, ESITA activities engage students in the use of newly acquired information technology (IT) skills and understandings while performing air and water quality research investigations. One project that ESITA students have become involved in relates to the currently relevant issue of elevated levels of lead found in drinking waters in Washington, D.C. Students based in the Bay Area have initiated and maintained E-mail correspondence with children who attend elementary schools in the D.C. area. After receiving a thorough explanation of required sampling procedures devised by the Bay Area students, the elementary school children have sent 500 ml water samples from their homes and schools to Berkeley along with information about the locations from which the water samples were collected. These samples were then prepared for lead analysis at Lawrence Hall of Science by ESITA students, who used resulting data to perform a preliminary assessment of the geospatial distribution of lead trouble spots throughout Washington, DC. Later, ESITA student scientists will work with students from the UC Berkeley School of Public Health to develop surveys and questionnaires that generate high quality information useful with regard to assessing the impact of the current lead crisis on younger children in the Washington, D.C. area. Through the application of new understandings to current, real-world environmental problems and issues such as that related to lead, positive changes in students' attitudes towards IT and science have occurred, which accompany

  3. Helping Italian science teachers to make earth and climate active lessons. Results of 3 years support with the ICLEEN project

    Science.gov (United States)

    Cattadori, M.

    2013-12-01

    It has been demonstrated that in Italy Earth and Climate System Sciences Education (ESS) is one of the scientific disciplines where science teachers show a greatest need in terms of professional support. Among the causes that have been reported we should mention: the predominance of science teachers with a degree in biological disciplines rather then geo-logical or physical topics, and the high interdisciplinarity of certain topics, in particular those related to the climate system. Furthermore, it was found that ESS topics are predominant in the science curricula of those grades in which have been reported the major students dropout rates during the whole italian school cycle . In this context, in 2010, the MUSE, the Museum of Science of Trento (Italy), created a web-based service named I-Cleen (Inquring on Climate and Energy www.icleen.muse.it). This is a tool aimed at promoting the collaboration among science teachers in order to share resources and enhance the professional collaboration by means of participatory methods and models belonging to the world of open source and open content. The main instrument of the I-CLEEN project is an online repository (with metadata compliant with the DCMI and LOM international standards) of teaching resources focused on Earth and Climate Sciences all published under the Creative Commons license Attribution 3.0 and therefore, belonging to the model of OER (Open Educational Resources). The service has been designed, developed and managed by a team consisting of very experiencing science teachers and scientists from the Museum and other partners research institutions. The editorial work is carried out online utilizing a specific platform made with LifeRay, a CMS (Content Management System) software that is open source and manageable in a single Java-frameworked environment using the dbase, the website, the editorial process and several web 2.0 services. The project has been subjected to two distinct testing activities in

  4. Transesterification of Waste Cooking Oil using Calcium Loaded on Deoiled Spent Bleaching Clay as A Solid Base Catalyst

    Directory of Open Access Journals (Sweden)

    Rehan Zainol Abidin

    2016-08-01

    Full Text Available Waste cooking oil has a high potential as a raw material in biodiesel production due to its abundant availability and cheapest among other feedstock. Hence transesterification reaction is carried out using waste cooking oil in this research. The objective of this study is to synthesize and characterize the catalyst. On the other hand, deoiled spent bleaching clay impregnated with 40% CaO utilized as a catalyst. Optimization was carried out on methanol to oil molar ratio (6:1-24:1, catalyst loading (3-10 wt.% and reaction duration (2-10 h. The catalyst of deoiled spent bleaching clay doped with 40% CaO was prepared by wet impregnation method and calcined at 500 °C for 4 hours. The catalyst shows high activity under optimum condition of 5 hours of reaction time, 12:1 of methanol to oil molar ratio with 7 wt.% of catalyst. The transesterification yields 84.7% methyl ester. Therefore, this catalyst has potential to be used in the transesterification of waste cooking oil in producing biodiesel due to its high activity. Copyright © 2016 BCREC GROUP. All rights reserved Received: 21st January 2016; Revised: 3rd March 2016; Accepted: 6th March 2016 How to Cite: Abidin, R.Z., Maniam G.P., Rahim, M.H.A. (2016. Transesterification of Waste Cooking Oil using Calcium Loaded on Deoiled Spent Bleaching Clay as A Solid Base Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2: 176-181 (doi:10.9767/bcrec.11.2.548.176-181 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.548.176-181

  5. Tropical Cyclone Activity in the High-Resolution Community Earth System Model and the Impact of Ocean Coupling

    Science.gov (United States)

    Li, Hui; Sriver, Ryan L.

    2018-01-01

    High-resolution Atmosphere General Circulation Models (AGCMs) are capable of directly simulating realistic tropical cyclone (TC) statistics, providing a promising approach for TC-climate studies. Active air-sea coupling in a coupled model framework is essential to capturing TC-ocean interactions, which can influence TC-climate connections on interannual to decadal time scales. Here we investigate how the choices of ocean coupling can affect the directly simulated TCs using high-resolution configurations of the Community Earth System Model (CESM). We performed a suite of high-resolution, multidecadal, global-scale CESM simulations in which the atmosphere (˜0.25° grid spacing) is configured with three different levels of ocean coupling: prescribed climatological sea surface temperature (SST) (ATM), mixed layer ocean (SLAB), and dynamic ocean (CPL). We find that different levels of ocean coupling can influence simulated TC frequency, geographical distributions, and storm intensity. ATM simulates more storms and higher overall storm intensity than the coupled simulations. It also simulates higher TC track density over the eastern Pacific and the North Atlantic, while TC tracks are relatively sparse within CPL and SLAB for these regions. Storm intensification and the maximum wind speed are sensitive to the representations of local surface flux feedbacks in different coupling configurations. Key differences in storm number and distribution can be attributed to variations in the modeled large-scale climate mean state and variability that arise from the combined effect of intrinsic model biases and air-sea interactions. Results help to improve our understanding about the representation of TCs in high-resolution coupled Earth system models, with important implications for TC-climate applications.

  6. Tooth bleaching using peroxide-containing agents: current status of safety issues.

    Science.gov (United States)

    Li, Y

    1998-08-01

    During the last 10 years, at-home tooth bleaching using peroxide-containing agents has quickly become well accepted. It is one of the most popular cosmetic dental procedures for whitening teeth. Although there are few disputes regarding their efficacy, concerns and debates have continued regarding the safety of peroxide-containing tooth bleaching agents. Potential carcinogenicity and genotoxicity of the peroxides used in bleaching agents are the two most persistent and controversial issues. This article reviews and discusses available information on carcinogenicity and genotoxicity of hydrogen peroxide and the potential risks associated with the use of peroxide-containing bleaching agents. Clinical studies reported after the 1996 international symposium on responses of oral tissues to peroxide-containing bleaching agents are also reviewed. Overall evidence supports the conclusion that the proper use of peroxide-containing at-home tooth bleaching agents is safe. However, potential adverse effects may occur in inappropriate applications, abuses, or the use of inappropriate products. At-home tooth bleaching should be monitored by dental professionals to maximize the benefits while minimizing potential risks.

  7. 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.

  8. Elevated temperatures and bleaching on a high latitude coral reef: the 1988 Bermuda event

    Science.gov (United States)

    Cook, Clayton B.; Logan, Alan; Ward, Jack; Luckhurst, Brian; Berg, Carl J.

    1990-03-01

    Sea temperatures were normal in Bermuda during 1987, when Bermuda escaped the episodes of coral bleaching which were prevalent throughout the Caribbean region. Survey transecs in 1988 on 4 6 m reefs located on the rim margin and on a lagoonal patch reef revealed bleaching only of zoanthids between May and July. Transect and tow surveys in August and September revealed bleaching of several coral species; Millepora alcicornis on rim reefs was the most extensively affected. The frequency of bleaching in this species, Montastrea annularis and perhaps Diploria labyrinthiformis was significantly higher on outer reefs than on inshore reefs. This bleaching period coincided with the longest period of elevated sea temperatures in Bermuda in 38 years (28.9 30.9°C inshore, >28° offshore). By December, when temperatures had returned to normal, bleaching of seleractinians continued, but bleaching of M. alcicornis on the outer reefs was greatly reduced. Our observations suggest that corals which normally experience wide temperature ranges are less sensitive to thermal stress, and that high-latitude reef corals are sensitive to elevated temperatures which are within the normal thermal range of corals at lower latitudes.

  9. 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.

  10. Recycling of water in bleached kraft pulp mills by using electrodialysis.

    Energy Technology Data Exchange (ETDEWEB)

    Fracaro, A. T.; Henry, M. P.; Pfromm, P.; Tsai, S.-P.

    1999-01-15

    Conservation of water in bleached kraft pulp mills by recycling the bleach plant effluent directly without treatment will cause accumulation of inorganic ''non-process elements'' (NPEs) and serious operational problems. In this work, an electrodialysis process is being developed for recycling the acidic bleach plant effluent of bleached kraft pulp mills. In this process, electrodialysis functions as a selective kidney to remove inorganic NPEs from bleach plant effluents, before they reach the recovery cycle. Acidic bleach plant effluents from several mills using bleaching sequences based on chlorine dioxide were characterized. The total dissolved solids were mostly inorganic NPEs. Sodium was the predominant cation and chloride was present at significant levels in all these effluents. In laboratory electrodialysis experiments, selective removal of chloride and potentially harmful cations, such as potassium, calcium, and magnesium, were removed efficiently. Rejection of organic compounds was up to 98%. Electrodialysis was shown to be resistant to membrane fouling and scaling, in a 100-hour laboratory experiment. Based on a model mill with 1,000 ton/day pulp production, the economic analysis suggests that the energy cost of electrodialysis is less than $200/day, and the capital cost of the stack is about $500,000.

  11. Relationships between temperature, bleaching and white syndrome on the Great Barrier Reef

    Science.gov (United States)

    Ban, S. S.; Graham, N. A. J.; Connolly, S. R.

    2013-03-01

    Coral bleaching and disease have often been hypothesized to be mutually reinforcing or co-occurring, but much of the research supporting this has only drawn an implicit connection through common environmental predictors. In this study, we examine whether an explicit relationship between white syndrome and bleaching exists using assemblage-level monitoring data from up to 112 sites on reef slopes spread throughout the Great Barrier Reef over 11 years of monitoring. None of the temperature metrics commonly used to predict mass bleaching performed strongly when applied to these data. Furthermore, the inclusion of bleaching as a predictor did not improve model skill over baseline models for predicting white syndrome. Similarly, the inclusion of white syndrome as a predictor did not improve models of bleaching. Evidence for spatial co-occurrence of bleaching and white syndrome at the assemblage level in this data set was also very weak. These results suggest the hypothesized relationship between bleaching and disease events may be weaker than previously thought, and more likely to be driven by common responses to environmental stressors, rather than directly facilitating one another.

  12. The influence of hair bleach on the ultrastructure of human hair with special reference to hair damage.

    Science.gov (United States)

    Imai, Takehito

    2011-05-01

    The influence of human hair bleaching agents with different bleaching strength on the ultrastructure of human hair was studied using a transmission electron microscope (TEM) and an energy dispersive X-ray spectrometer equipped with TEM (EDS-TEM). Two kinds of bleaching agents were used: a lightener agent with a weak bleaching effect and a powder-bleach with a stronger bleaching effect. From the comparison of the bleaching properties obtained by the electronic staining of black and white hair samples, it was suggested that the permeability of hair was increased by bleaching, and there was an increase of the stainability of hair subjected to electronic staining. The bleaching action provoked the decomposition of melanin granules and the flow out of granular contents into the intermacrofibrillar matrix. Some metal elements were detected in the melanin granular matrix by EDS-TEM. As a result, the diffusion of metal elements into the intermacrofibrillar matrix promoted further damage to the hair by catalytic action with the hydrogen peroxide in the bleaching agents outside the melanin granules. Further study will lead us to the edge of the development of a new bleaching agent, which reacts only with melanin granules and causes the minimum of damage to outside the melanin granules.

  13. Skeletal isotope records of growth perturbations in Porites corals during the 1997-1998 mass bleaching event

    Science.gov (United States)

    Suzuki, A.; Gagan, M.; Fabricius, K.; Isdale, P.; Yukino, I.; Kawahata, H.

    2003-04-01

    Severe coral bleaching occurred throughout the tropics in 1997/98. We report skeletal UV fluorescence, oxygen isotope, and carbon isotope evidence for perturbations in coral skeletal growth due to bleaching at Ishigaki Island, Japan, and Pandora Reef, Great Barrier Reef. Bleached corals showed abrupt reductions in skeletal extension rate immediately after summer temperature maxima, indicating that bleaching inhibits coral calcification. A colony growing at the low tide line in Ishigaki exhibited clear blue UV fluorescent bands associated with recurrent growth interruptions. Based on the length of time-gaps observed in the annual isotopic cycle, the typical time required for a coral to recover from bleaching is estimated to be about 5--6 months. The effect of bleaching on the oxygen isotope ratio -- temperature relationship was negligible. However, the Ishigaki corals showed lower carbon isotope ratios during bleaching indicating depressed coral metabolism associated with a reduction in calcification. In contrast, skeletal carbon isotope ratios in the Pandora Reef corals exhibited little change in response to bleaching. This is because the records for Pandora Reef were derived from the shaded sides of coral colonies, where algal photosynthesis was particularly slow prior to bleaching, thus subduing the carbon isotope response to bleaching. Taken together, the isotopic and UV fluorescence signals can be used to reconstruct past bleaching events.

  14. Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005.

    Science.gov (United States)

    Eakin, C Mark; Morgan, Jessica A; Heron, Scott F; Smith, Tyler B; Liu, Gang; Alvarez-Filip, Lorenzo; Baca, Bart; Bartels, Erich; Bastidas, Carolina; Bouchon, Claude; Brandt, Marilyn; Bruckner, Andrew W; Bunkley-Williams, Lucy; Cameron, Andrew; Causey, Billy D; Chiappone, Mark; Christensen, Tyler R L; Crabbe, M James C; Day, Owen; de la Guardia, Elena; Díaz-Pulido, Guillermo; DiResta, Daniel; Gil-Agudelo, Diego L; Gilliam, David S; Ginsburg, Robert N; Gore, Shannon; Guzmán, Héctor M; Hendee, James C; Hernández-Delgado, Edwin A; Husain, Ellen; Jeffrey, Christopher F G; Jones, Ross J; Jordán-Dahlgren, Eric; Kaufman, Les S; Kline, David I; Kramer, Philip A; Lang, Judith C; Lirman, Diego; Mallela, Jennie; Manfrino, Carrie; Maréchal, Jean-Philippe; Marks, Ken; Mihaly, Jennifer; Miller, W Jeff; Mueller, Erich M; Muller, Erinn M; Orozco Toro, Carlos A; Oxenford, Hazel A; Ponce-Taylor, Daniel; Quinn, Norman; Ritchie, Kim B; Rodríguez, Sebastián; Ramírez, Alberto Rodríguez; Romano, Sandra; Samhouri, Jameal F; Sánchez, Juan A; Schmahl, George P; Shank, Burton V; Skirving, William J; Steiner, Sascha C C; Villamizar, Estrella; Walsh, Sheila M; Walter, Cory; Weil, Ernesto; Williams, Ernest H; Roberson, Kimberly Woody; Yusuf, Yusri

    2010-11-15

    The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

  15. Seasonal mesophotic coral bleaching of Stylophora pistillata in the Northern Red Sea.

    Directory of Open Access Journals (Sweden)

    Orit Nir

    Full Text Available Coral bleaching occurs when environmental stress induces breakdown of the coral-algae symbiosis and the host initiates algae expulsion. Two types of coral bleaching had been thoroughly discussed in the scientific literature; the first is primarily associated with mass coral bleaching events; the second is a seasonal loss of algae and/or pigments. Here, we describe a phenomenon that has been witnessed for repeated summers in the mesophotic zone (40-63 m in the northern Red Sea: seasonal bleaching and recovery of several hermatypic coral species. In this study, we followed the recurring bleaching process of the common coral Stylophora pistillata. Bleaching occurred from April to September with a 66% decline in chlorophyll a concentration, while recovery began in October. Using aquarium and transplantation experiments, we explored environmental factors such as temperature, photon flux density and heterotrophic food availability. Our experiments and observations did not yield one single factor, alone, responsible for the seasonal bleaching. The dinoflagellate symbionts (of the genus Symbiodinium in shallow (5 m Stylophora pistillata were found to have a net photosynthetic rate of 56.98-92.19 µmol O2 cm(-2 day(-1. However, those from mesophotic depth (60 m during months when they are not bleached are net consumers of oxygen having a net photosynthetic rate between -12.86 - (-10.24 µmol O2 cm(-2 day(-1. But during months when these mesophotic corals are partially-bleached, they yielded higher net production, between -2.83-0.76 µmol O2 cm(-2 day(-1. This study opens research questions as to why mesophotic zooxanthellae are more successfully meeting the corals metabolic requirements when Chl a concentration decreases by over 60% during summer and early fall.

  16. Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005.

    Directory of Open Access Journals (Sweden)

    C Mark Eakin

    Full Text Available BACKGROUND: The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS: Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE: Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

  17. Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

    Science.gov (United States)

    Eakin, C. Mark; Morgan, Jessica A.; Heron, Scott F.; Smith, Tyler B.; Liu, Gang; Alvarez-Filip, Lorenzo; Baca, Bart; Bartels, Erich; Bastidas, Carolina; Bouchon, Claude; Brandt, Marilyn; Bruckner, Andrew W.; Bunkley-Williams, Lucy; Cameron, Andrew; Causey, Billy D.; Chiappone, Mark; Christensen, Tyler R. L.; Crabbe, M. James C; Day, Owen; de la Guardia, Elena; Díaz-Pulido, Guillermo; DiResta, Daniel; Gil-Agudelo, Diego L.; Gilliam, David S.; Ginsburg, Robert N.; Gore, Shannon; Guzmán, Héctor M.; Hendee, James C.; Hernández-Delgado, Edwin A.; Husain, Ellen; Jeffrey, Christopher F. G.; Jones, Ross J.; Jordán-Dahlgren, Eric; Kaufman, Les S.; Kline, David I.; Kramer, Philip A.; Lang, Judith C.; Lirman, Diego; Mallela, Jennie; Manfrino, Carrie; Maréchal, Jean-Philippe; Marks, Ken; Mihaly, Jennifer; Miller, W. Jeff; Mueller, Erich M.; Muller, Erinn M.; Orozco Toro, Carlos A.; Oxenford, Hazel A.; Ponce-Taylor, Daniel; Quinn, Norman; Ritchie, Kim B.; Rodríguez, Sebastián; Ramírez, Alberto Rodríguez; Romano, Sandra; Samhouri, Jameal F.; Sánchez, Juan A.; Schmahl, George P.; Shank, Burton V.; Skirving, William J.; Steiner, Sascha C. C.; Villamizar, Estrella; Walsh, Sheila M.; Walter, Cory; Weil, Ernesto; Williams, Ernest H.; Roberson, Kimberly Woody; Yusuf, Yusri

    2010-01-01

    Background The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Methodology/Principal Findings Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Conclusions/Significance Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate. PMID:21125021

  18. Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide.

    Science.gov (United States)

    Smith, Tucker J; Foegeding, E Allen; Drake, MaryAnne

    2015-10-01

    Whey protein is a highly functional food ingredient used in a wide variety of applications. A large portion of fluid whey produced in the United States is derived from Cheddar cheese manufacture and contains annatto (norbixin), and therefore must be bleached. The objective of this study was to compare sensory and functionality differences between whey protein isolate (WPI) bleached by benzoyl peroxide (BP) or hydrogen peroxide (HP). HP and BP bleached WPI and unbleached controls were manufactured in triplicate. Descriptive sensory analysis and gas chromatography-mass spectrometry were conducted to determine flavor differences between treatments. Functionality differences were evaluated by measurement of foam stability, protein solubility, SDS-PAGE, and effect of NaCl concentration on gelation relative to an unbleached control. HP bleached WPI had higher concentrations of lipid oxidation and sulfur containing volatile compounds than both BP and unbleached WPI (P protein loss at pH 4.6 of WPI decreased by bleaching with either hydrogen peroxide or benzoyl peroxide (P whey with either BP or HP resulted in protein degradation, which likely contributed to functionality differences. These results demonstrate that bleaching has flavor effects as well as effects on many of the functionality characteristics of whey proteins. Whey protein isolate (WPI) is often used for its functional properties, but the effect of oxidative bleaching chemicals on the functional properties of WPI is not known. This study identifies the effects of hydrogen peroxide and benzoyl peroxide on functional and flavor characteristics of WPI bleached by hydrogen and benzoyl peroxide and provides insights for the product applications which may benefit from bleaching. © 2015 Institute of Food Technologists®

  19. Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics

    Directory of Open Access Journals (Sweden)

    Sérgio Augusto Morey Ourique

    2011-10-01

    Full Text Available The wide use of dental bleaching treatment has brought concern about the possible effects of hydrogen peroxide on dental tissue and restorative materials. The objective of this study was to evaluate in vitro the effect of nightguard bleaching on the surface roughness of dental ceramics after different periods of bleaching treatment. Fifteen specimens of 5 × 3 × 1 mm were created with three dental ceramics following the manufacturers' instructions: IPS Classic (Ivoclar-Vivadent; IPS d.Sign (Ivoclar-Vivadent; and VMK-95 (Vita. A profilometer was used to evaluate baseline surface roughness (Ra values of all ceramics by five parallel measurements with five 0.25 mm cut off (Λc at 0.1 mm/s. Afterwards, all specimens were submitted to 6-h daily bleaching treatments with 10% or 16% carbamide peroxide (Whiteness- FGM for 21 days, while control groups from each ceramic system were stored in artificial saliva. The surface roughness of all groups was evaluated after 18 h, 42 h, 84 h, and 126 h of bleaching treatment. The surface roughness of each specimen (n = 5 was based on the mean value of five parallel measurements in each time and all data were submitted to two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05. No significant differences in ceramic surface roughness were observed between untreated and bleached ceramic surfaces, regardless of bleaching intervals or bleaching treatments. This study provided evidence that at-home bleaching systems do not cause detrimental effects on surface roughness of dental ceramics.

  20. The Delineation of Coral Bleaching Thresholds and Future Reef Health, Little Cayman Cayman Islands

    Science.gov (United States)

    Manfrino, C.; Van Hooidonk, R. J.; Manzello, D.; Hendee, J.

    2011-12-01

    The global rise in sea temperature through anthropogenic climate change is affecting coral reef ecosystems through a phenomenon known as coral bleaching; a common reaction to thermally induced physiological stress in reef-building corals that often leads to coral mortality. We describe aspects of the most prevalent episode of coral bleaching ever recorded at Little Cayman, Cayman Islands, during the fall of 2009. Scleractinian coral species exhibiting susceptibility to thermal stress and bleaching in Little Cayman were, in order, Siderastrea siderea, Montastraea annularis, and Montastraea faveolata, while Diplora strigosa and Agaricia spp. were less so, yet still showed considerable bleaching prevalence and severity. In contrast, the least susceptible were Porites porites, Porites astreoides, and Montastraea cavernosa. These observations and other reported observations of coral bleaching, together with 29 years (1982 - 2010) of satellite-derived sea surface temperatures, were used in a Degree Heating Weeks (DHW) and Peirce Skill Score (PSS) analysis to calculate a bleaching threshold above which bleaching was expected to occur. A threshold of 4.2 DHW had the highest skill, with a PSS of 0.70. This threshold and susceptibility ranking are used in combination with SST data from global, coupled ocean-atmosphere general circulation models (GCM) from the fourth IPCC assessment to forecast future reef health on Little Cayman. While these GCMs possess skill in reproducing many aspects of climate, they vary in their ability to correctly capture such parameters as the tropical ocean seasonal cycle and El Niño Southern Oscillation (ENSO) variability. These model weaknesses likely reduce the skill of coral bleaching predictions. To overcome this, a multi-model ensemble of GCMs are corrected for their mean, annual cycle and ENSO variability prior to calculating future thermal stress. Preliminary results show that from 2045 on Little Cayman is likely to see more than two

  1. Seasonal mesophotic coral bleaching of Stylophora pistillata in the Northern Red Sea.

    Science.gov (United States)

    Nir, Orit; Gruber, David F; Shemesh, Eli; Glasser, Eliezra; Tchernov, Dan

    2014-01-01

    Coral bleaching occurs when environmental stress induces breakdown of the coral-algae symbiosis and the host initiates algae expulsion. Two types of coral bleaching had been thoroughly discussed in the scientific literature; the first is primarily associated with mass coral bleaching events; the second is a seasonal loss of algae and/or pigments. Here, we describe a phenomenon that has been witnessed for repeated summers in the mesophotic zone (40-63 m) in the northern Red Sea: seasonal bleaching and recovery of several hermatypic coral species. In this study, we followed the recurring bleaching process of the common coral Stylophora pistillata. Bleaching occurred from April to September with a 66% decline in chlorophyll a concentration, while recovery began in October. Using aquarium and transplantation experiments, we explored environmental factors such as temperature, photon flux density and heterotrophic food availability. Our experiments and observations did not yield one single factor, alone, responsible for the seasonal bleaching. The dinoflagellate symbionts (of the genus Symbiodinium) in shallow (5 m) Stylophora pistillata were found to have a net photosynthetic rate of 56.98-92.19 µmol O2 cm(-2) day(-1). However, those from mesophotic depth (60 m) during months when they are not bleached are net consumers of oxygen having a net photosynthetic rate between -12.86 - (-10.24) µmol O2 cm(-2) day(-1). But during months when these mesophotic corals are partially-bleached, they yielded higher net production, between -2.83-0.76 µmol O2 cm(-2) day(-1). This study opens research questions as to why mesophotic zooxanthellae are more successfully meeting the corals metabolic requirements when Chl a concentration decreases by over 60% during summer and early fall.

  2. Estimates of late Cenozoic climate change relevant to Earth surface processes in tectonically active orogens

    Directory of Open Access Journals (Sweden)

    S. G. Mutz

    2018-04-01

    Full Text Available The denudation history of active orogens is often interpreted in the context of modern climate gradients. Here we address the validity of this approach and ask what are the spatial and temporal variations in palaeoclimate for a latitudinally diverse range of active orogens? We do this using high-resolution (T159, ca. 80  ×  80 km at the Equator palaeoclimate simulations from the ECHAM5 global atmospheric general circulation model and a statistical cluster analysis of climate over different orogens (Andes, Himalayas, SE Alaska, Pacific NW USA. Time periods and boundary conditions considered include the Pliocene (PLIO,  ∼  3 Ma, the Last Glacial Maximum (LGM,  ∼  21 ka, mid-Holocene (MH,  ∼  6 ka, and pre-industrial (PI, reference year 1850. The regional simulated climates of each orogen are described by means of cluster analyses based on the variability in precipitation, 2 m air temperature, the intra-annual amplitude of these values, and monsoonal wind speeds where appropriate. Results indicate the largest differences in the PI climate existed for the LGM and PLIO climates in the form of widespread cooling and reduced precipitation in the LGM and warming and enhanced precipitation during the PLIO. The LGM climate shows the largest deviation in annual precipitation from the PI climate and shows enhanced precipitation in the temperate Andes and coastal regions for both SE Alaska and the US Pacific Northwest. Furthermore, LGM precipitation is reduced in the western Himalayas and enhanced in the eastern Himalayas, resulting in a shift of the wettest regional climates eastward along the orogen. The cluster-analysis results also suggest more climatic variability across latitudes east of the Andes in the PLIO climate than in other time slice experiments conducted here. Taken together, these results highlight significant changes in late Cenozoic regional climatology over the last  ∼  3 Myr. Comparison

  3. Estimates of late Cenozoic climate change relevant to Earth surface processes in tectonically active orogens

    Science.gov (United States)

    Mutz, Sebastian G.; Ehlers, Todd A.; Werner, Martin; Lohmann, Gerrit; Stepanek, Christian; Li, Jingmin

    2018-04-01

    The denudation history of active orogens is often interpreted in the context of modern climate gradients. Here we address the validity of this approach and ask what are the spatial and temporal variations in palaeoclimate for a latitudinally diverse range of active orogens? We do this using high-resolution (T159, ca. 80 × 80 km at the Equator) palaeoclimate simulations from the ECHAM5 global atmospheric general circulation model and a statistical cluster analysis of climate over different orogens (Andes, Himalayas, SE Alaska, Pacific NW USA). Time periods and boundary conditions considered include the Pliocene (PLIO, ˜ 3 Ma), the Last Glacial Maximum (LGM, ˜ 21 ka), mid-Holocene (MH, ˜ 6 ka), and pre-industrial (PI, reference year 1850). The regional simulated climates of each orogen are described by means of cluster analyses based on the variability in precipitation, 2 m air temperature, the intra-annual amplitude of these values, and monsoonal wind speeds where appropriate. Results indicate the largest differences in the PI climate existed for the LGM and PLIO climates in the form of widespread cooling and reduced precipitation in the LGM and warming and enhanced precipitation during the PLIO. The LGM climate shows the largest deviation in annual precipitation from the PI climate and shows enhanced precipitation in the temperate Andes and coastal regions for both SE Alaska and the US Pacific Northwest. Furthermore, LGM precipitation is reduced in the western Himalayas and enhanced in the eastern Himalayas, resulting in a shift of the wettest regional climates eastward along the orogen. The cluster-analysis results also suggest more climatic variability across latitudes east of the Andes in the PLIO climate than in other time slice experiments conducted here. Taken together, these results highlight significant changes in late Cenozoic regional climatology over the last ˜ 3 Myr. Comparison of simulated climate with proxy-based reconstructions for the MH and

  4. Geochemical evidence for active tropical serpentinization in the Santa Elena Ophiolite, Costa Rica: An analog of a humid early Earth?

    Science.gov (United States)

    Sánchez-Murillo, Ricardo; Gazel, Esteban; Schwarzenbach, Esther M.; Crespo-Medina, Melitza; Schrenk, Matthew O.; Boll, Jan; Gill, Ben C.

    2014-05-01

    Serpentinization is a planetary process that has important consequences on geochemical cycles, supporting microbial activity through the formation of H2 and CH4 and having the potential to sequester atmospheric CO2. We present geochemical evidence of active serpentinization in the Santa Elena Ophiolite, Costa Rica which is sustained by peridotites with a degree of serpentinization less than 50% with no evidence of an internal heat source. Average spring water temperatures are 29.1°C. Two hyperalkaline spring systems were discovered, with a spring fluid pH up to 11.18. The fluids are characterized by low Mg (1.0-5.9 mg/L) and K (1.0-5.5 mg/L) and relative high Ca (29-167 mg/L), Na (16-27 mg/L), Cl (26-29 mg/L), hydroxide (41-63 mg/L), and carbonate (31-49 mg/L). Active CH4 (24.3% v/v) vents coupled with carbonate deposits (δ13CCO2 =-27 to -14‰; δ18OCO2 =-17 to - 6‰) also provide evidence for active serpentinization and carbonation. Isotope ratios of the alkaline fluids (δ18O = -7.9‰, δ2H = -51.4‰) and groundwater (δ18O = -7.6‰; δ2H = -48.0‰) suggests that, during base flow recession, springs are fed by groundwater circulation. Methanogenic Archaea, which comprises a relatively high percentage of the 16S rRNA gene tag sequences, suggests that biological methanogenesis may play a significant role in the system. Santa Elena's extreme varying weather results in a scenario that could be of significant importance for (a) improving the knowledge of conditions on a humid early Earth or Mars that had periodic changes in water supply, (b) revealing new insights on serpentinizing solute transport, and (c) modeling hydrogeochemical responses as a function of recharge.

  5. Rare earth elements in core marine sediments of coastal East Malaysia by instrumental neutron activation analysis.

    Science.gov (United States)

    Ashraf, Ahmadreza; Saion, Elias; Gharibshahi, Elham; Mohamed Kamari, Halimah; Chee Kong, Yap; Suhaimi Hamzah, Mohd; Suhaimi Elias, Md

    2016-01-01

    A study was carried out on the concentration of REEs (Dy, Sm, Eu,Yb, Lu, La and Ce) that are present in the core marine sediments of East Malaysia from three locations at South China Sea and one location each at Sulu Sea and Sulawesi Sea. The sediment samples were collected at a depth of between 49 and 109 m, dried, and crushed to powdery form. The entire core sediments prepared for Instrumental Neutron Activation Analysis (INAA) were weighted approximately 0.0500 g to 0.1000 g for short irradiation and 0.1500 g to 0.2000 g for long irradiation. The samples were irradiated with a thermal neutron flux of 4.0×10(12) cm(-2) s(-1) in a TRIGA Mark II research reactor operated at 750 kW. Blank samples and standard reference materials SL-1 were also irradiated for calibration and quality control purposes. It was found that the concentration of REEs varies in the range from 0.11 to 36.84 mg/kg. The chondrite-normalized REEs for different stations suggest that all the REEs are from similar origins. There was no significant REEs contamination as the enrichment factors normalized for Fe fall in the range of 0.42-2.82. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Increase of positive active material utilization in lead-acid batteries using diatomaceous earth additives

    Science.gov (United States)

    McAllister, Simon D.; Ponraj, Rubha; Cheng, I. Francis; Edwards, Dean B.

    In this study we examined the use of diatomites to improve the discharge capacity and utilization of the positive electrode of the lead-acid battery. A large fraction of the positive electrode performance of this battery system (half-reaction shown below) is based on the ionic conduction of sulfuric acid through the plate. PbO2(s) + HSO 4 - + 3H + + 2e - → PbSO 4(s) + 2H 2O. The porous diatomites improve the ionic conduction by providing channels in addition to the natural ones formed within the paste. The choice of diatomite is based on its stability in the oxidative and corrosive environment of the lead-acid battery, as well as its naturally high porosity. The diatomite particles were size sorted into 20-30 μm, 30-53 μm, 53-74 μm, and 74-90 μm fractions, and the discharge performances of each were measured at 1%, 3%, and 5% weight ratios. The best performance was observed with 53-74 μm particles with an optimum weight ratio of 3%. At this size fraction and weight ratio, diatomites show a 12.7% increase in active material utilization and a 9.3% increase in specific capacity at high rate discharge (50 mA cm -2) relative to control samples without diatomites.

  7. 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.

    coral genera were quantified and compared. Also, sea surface temperature (SST) and photosynthetically active radiation (PAR) were monitored simultaneously and compared. Results showed an increase in the intensity of SST and PAR in 2014 compared to 2013...

  8. High Resolution 3D Earth Observation Data Analysis for Safeguards Activities

    International Nuclear Information System (INIS)

    D'Angelo, P.; Eineder, M.; Rossi, C.

    2015-01-01

    This paper provides an overview of the investigations performed in the last three years at DLR and highlights the application of SAR and optical data for 3D analysis in the context of Safeguards. The Research Center Juelich and the adjacent open cut mines were used as main test site, and a comprehensive stack of ascending and descending TerraSAR data was acquired over two years. TerraSAR data acquisition was performed, and various ways to visualize stacks of radar images were evaluated. Building height estimation was performed using a combination of ascending-descending radar images, as well as height-form-shadow, height-from-layover. A tutorial on building signatures from SAR images highlighted the sensor specific imaging characteristics. These topics were particularly relevant in safeguards activity with a ''small-budget'' as only a single image - or a couple - were employed. Interferometric coherence map interpretation allows the detection of used dirt roads. Digital surface models (DSM) were generated from TanDEM-X interferometric data and from optical VHR data. Sub-meterWorldview-2 and GeoEye-1 data was processed into highly detailed DSM with a grid spacing of 1 m, showing building structures. 3D change and volume detection was performed with both optical and radar DSMs. The TanDEM-X DSMs proved useful for volume change detection and computation in mining areas, and down to building level with optical data. Virtual fly-through were found to be a good tool to provide an intuitive understanding of site structure and might be useful for inspector briefing. Tools for most of the above mentioned tasks have been developed for the ENVI environment and can be used by IAEA internally. (author)

  9. Comparison of Radicular Peroxide Leakage from four Commonly used Bleaching agents following Intracoronal Bleaching in Endodontically treated teeth - An In Vitro Study.

    Science.gov (United States)

    Madhu, Ks; Hegde, Swaroop; Mathew, Sylvia; Lata, DA; Bhandi, Shilpa H; N, Shruthi

    2013-08-01

    Non vital bleaching is simple, conservative procedure for esthetic correction of discolored endodontically treated teeth. The aim of this study was to determine and compare the amount of peroxide leakage from four different bleaching agents i.e superoxol, sodium perborate, combination of superoxol & sodium perborate and carbamide peroxide during intracoronal bleaching, as the safe and effective bleaching is the need of the hour. 50 extracted maxillary centrals were selected for the study. Following standardized protocol access, cleaning and shaping by step back technique and obturation was done using guttapercha and AH plus sealer. Access was sealed with Cavit G and outer root surface was coated with wax and nail varnish. The teeth were separated into crown and root and the root portion was placed in plastic tube containing distilled water for 7days.After incubation, 3mm of gutta-percha was removed below CEJ and 2mm glass ionomer cement base was placed. Grouped into five categories based on the bleaching agent placed in pulp chamber as -group1 (control)-distilled water, group 2-sodium perborate with distilled water , group 3- 30% hydrogen peroxide ,group 4-mixture of sodium perborate and 30% hydrogen peroxide and group 5-10% carbamide peroxide gel. Peroxide leakage was measured after 24hrs using ferrothiocyanate method and optical density using spectrophotometer. Statistical analysis of the data was conducted using ANOVA and multiple comparisons within the groups was done using BONFERRONI method (Post-Hoc tests). The results showed highest peroxide penetration from 30% hydrogen peroxide followed by mixture of sodium perborate with 30% hydrogen peroxide, mixture of sodium perborate with distilled water and least penetration from 10% carbamide peroxide gel. The results were statistically significant. Radicular peroxide leakage in 10% carbamide peroxide was significantly lower than the other tested bleaching agents making it a very safe alternative for intracoronal

  10. Sustainable Systems for exploration, stays with increased duration in LEO and Earth application -an overview about life support activities

    Science.gov (United States)

    Slenzka, Klaus; Duenne, Matthias

    Solar system exploration with extended stays in totally closed habitats far away from Earth as well as longer stays in LEO requires intensive preparatory activities. Activities supporting life in a more or less close meaning are essential in this context -on a scientific as well as on a technical level. These needed activities are supporting life by e.g.: i) increasing knowledge about the impact of single and combined effects of different exploration related environmental conditions (e. g. microgravity, radiation, reduced pressure and temperature, lunar soil etc.) on biological systems. This is needed to enable safe life of humans itself as well as safe operating of required bioregenerative life support systems. Thus, different human cell types as well as representatives of bioregenerative life support system protagonists (algae, bacteria as well as higher organisms) needs to be addressed. ii) provision of required consumables (oxygen, food, energy equivalents etc.) on site, mainly via bioregenerative life support systems, Bio-ISRU-units etc. Preparation is needed on a scientific as well as technological level. iii) ensuring reduced negative effects on humans (and partially also equipment), which could be caused by living in a closed habitat in general (and thus being not space related per se): E. g. detection systems for the quality of water and air, antimicrobial and selfhealing as well as anti-icing materials without dangerous hazard substances, psychological health enhancing components etc. Referring payloads for above mentioned investigations (scientific evaluation and technology demonstration) must be developed. Extended stays and extended closure in habitats without the possibility of material transport into and out of the system are leading to the necessity of more autonomous technologies and sustainable processes. Latter one will rely mainly on biological processes and structures, which increases additionally the necessity of an intensive scientific and

  11. Photoluminescence properties and local electronic structures of rare earth-activated Sr3AlO4F

    International Nuclear Information System (INIS)

    Fang, Y.; Li, Y.Q.; Qiu, T.; Delsing, A.C.A.; With, G. de; Hintzen, H.T.

    2010-01-01

    Photoluminescence properties and local electronic structures of rare earth (Eu 3+ and Ce 3+ ) activated Sr 3 AlO 4 F have been studied. X-ray powder diffraction data indicated that the activator ions of Eu 3+ and Ce 3+ can be incorporated into the Sr 3 AlO 4 F lattice and formed limited solid solutions of Sr 3-2x Ln x Na x AlO 4 F (Ln = Eu, Ce) with Na + as a charge compensator ion. The local structure around Sr sites was initially explored using Eu-activated Sr 3 AlO 4 F as a structural probe. Sr 3 AlO 4 F:Eu 3+ exhibits orange-red emission ranging from 520 to 740 nm with a maximum peak at about 619 nm mainly originating from the 5 D 0 → 7 F J (J = 0, 1, 2, 3, 4) transitions, indicating that Eu exists mainly in the trivalent state due to a strong oxidative lattice in Sr 3 AlO 4 F. Sr 3 AlO 4 F:Ce 3+ shows an unusual long-wavelength 4f → 5d excitation band of Ce 3+ at about 405 nm due to a large crystal field splitting of the 5d levels of Ce 3+ in relation to its crystal structure. Under near-UV excitation in the range of 375-405 nm, Sr 3 AlO 4 F:Ce 3+ exhibits efficient blue-green emission at about 506 nm. Given high absorption and efficient excitation in the near-UV region, Sr 3 AlO 4 F:Ce 3+ demonstrates a potential blue-green emitting phosphor for applications in white LED lighting.

  12. Recent trends of high-latitude vegetation activity assessed and explained by contrasting modelling approaches with earth observation data

    Science.gov (United States)

    Forkel, M.; Carvalhais, N.; Reichstein, M.; Thonicke, K.

    2012-04-01

    Active Radiation) from SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and MERIS (Medium Resolution Imaging Spectrometer). Photosynthetic activity was diagnosed through gross primary production (GPP) estimates from three different approaches: a data-driven upscaling algorithm based on a model-tree ensemble (MTE) and global-distributed eddy-covariance site measurements of carbon fluxes (FLUXNET); a land surface scheme of an earth system model (JSBACH, Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg); and a dynamic global vegetation model (LPJ, Lund-Potsdam-Jena DGVM). Trends in GPP from the different approaches were compared against remotely sensed trends in vegetation activity. The comparison was based on time series decomposition methods and a break point analysis to assess trends and trend changes in the observed and modelled variables. We used regression analysis to identify drivers of these trends, considering as explanatory variables temperature, precipitation, radiation and drought indicators as well as remotely sensed land cover and burned areas. Our results show that global ecosystem models are able to reproduce the observed temperature-driven greening in the 80's. In the 90's, the data-driven GPP model (MTE-FLUXNET) simulates a slight decline of photosynthetic activity in the boreal forest, which is due to the fact that it is forced with FAPAR observations. However, during this decade, the two process-oriented models (JSBACH and LPJ) show still an increase in photosynthetic activity instead of the observed browning in the boreal region. These results highlight the limitations of process models in diagnosing vegetation dynamics at decadal scales in the boreal regions, which can be related to inappropriate representations of fire activity, drought effects and insect disturbances. Overall, our analyses show that integrating remotely sensed fields on vegetation activity and empirically inferred global flux fields contributes to a critical appraisal of model

  13. Atmospheric depositions of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology

    International Nuclear Information System (INIS)

    Allajbeu, Sh.; Lazo, P.; Yushin, N.S.; Frontasyeva, M.V.; Qarri, F.; Duliu, O.G.

    2015-01-01

    Rare earth elements (REE) are conservative elements, scarcely derived from anthropogenic sources. The mobilization of REE in the environment requires their monitoring in environmental matrices, where they are mainly present at trace levels. The results on determination of the content of 11 elements by epithermal neutron activation analysis (ENAA) at the IBR-2 reactor in Dubna in carpet-forming moss species Hypnum cupressiforme collected from 44 sampling sites over the whole Albanian territory are presented and discussed. The paper is focused on Sc and lanthanides, as well as Fe and Th, the last ones showing correlations with the investigated REE. With the exception of Fe, all other elements were never determined in the air deposition of Albania. The STATISTICA TM 10 software was used for data analysis. The median values for the content of elements under investigation were compared to those in Bulgaria, Macedonia, Romania and Serbia, as well as Norway selected as a pristine area. Therefore, it was shown that the accumulation of REE in mosses is associated with the wind blown metal-enriched soils that are pointed out as the main emitting factor. [ru

  14. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    Science.gov (United States)

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation.

  15. The AFIS experiment: Detecting low energetic antiprotons in a low earth orbit, using an active target detector

    Energy Technology Data Exchange (ETDEWEB)

    Poeschl, Thomas; Gaisbauer, Dominic; Greenwald, Daniel; Hahn, Alexander; Hauptmann, Philipp; Konorov, Igor; Meng, Lingxin; Paul, Stephan [Physics Department E18, Technische Universitaet Muenchen (Germany); Losekamm, Martin [Physics Department E18, Technische Universitaet Muenchen (Germany); Institute of Astronautics, Technische Universitaet Muenchen (Germany); Renker, Dieter [Physics Department E17, Technische Universitaet Muenchen (Germany)

    2014-07-01

    Since the first observation of geomagnetically trapped antiprotons by the PAMELA experiment and the new results on the positron excess by the AMS-02 experiment, the creation and transport of antimatter in the Earth's upper atmosphere attracts more and more attention both at theoretical and experimental side. For this reason the AFIS experiment was initiated to measure the flux of low energetic antiprotons in the South Atlantic Anomaly (SAA). We developed an active target detector made from scintillating fibers connected to silicon photomultipliers which allows to detect antiprotons in the energy interval of about 30 MeV-100 MeV. The stopping curve of incoming antiprotons (Bragg peak) and the signal of outgoing pions created from the annihilation, are used for particle identification as well as triggering. We plan to implement this detector on a 3 unit cubesat satellite in the framework the 'Move2Warp' mission, which is carried out as a student project by the Technische Universitaet Muenchen.

  16. Use of xylanase in the TCF bleaching of eucalyptus kraft pulp

    Energy Technology Data Exchange (ETDEWEB)

    Roncero, B.; Vidal, T.; Torres, A.L.; Colom, J.F. [Universitat Politecnia de Catalunya, Terrassa (Spain)

    1996-10-01

    Environmental pressures are forcing the pulp and paper industry to develop new technologies that reduce or eliminate the presence of various contaminants in bleaching plant effluents. Oxygen delignification techniques, replacement of elemental chlorine with chlorine dioxide, ozone, hydrogen peroxide and new agents as well as the use of xylanase enzymes for biobleaching, reduce o eliminate the production of chlorinated organic substances. This paper compares the sequence XOZP with OZP in the bleaching of Eucalyptus globulus kraft pulps. It has been studied the influence of enzymatic treatment on the consumption of bleaching agents: ozone and hydrogen peroxide. Chemical, physical, optical and refining properties of pulps, as well as COD and colour of effluent are also studied. The xylanase treatment is positive and it is possible to manufacture fully bleached pulps at high brightness and viscosity without using chlorine compounds at a low ozone and hydrogen peroxide consumption.

  17. Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching

    KAUST Repository

    Pogoreutz, Claudia

    2017-04-21

    The disruption of the coral-algae symbiosis (coral bleaching) due to rising sea surface temperatures has become an unprecedented global threat to coral reefs. Despite decades of research, our ability to manage mass bleaching events remains hampered by an incomplete mechanistic understanding of the processes involved. In this study, we induced a coral bleaching phenotype in the absence of heat and light stress by adding sugars. The sugar addition resulted in coral symbiotic breakdown accompanied by a fourfold increase of coral-associated microbial nitrogen fixation. Concomitantly, increased N:P ratios by the coral host and algal symbionts suggest excess availability of nitrogen and a disruption of the nitrogen limitation within the coral holobiont. As nitrogen fixation is similarly stimulated in ocean warming scenarios, here we propose a refined coral bleaching model integrating the cascading effects of stimulated microbial nitrogen fixation. This model highlights the putative role of nitrogen-fixing microbes in coral holobiont functioning and breakdown.

  18. Post-bleaching coral community change on southern Maldivian reefs: is there potential for rapid recovery?

    Science.gov (United States)

    Perry, C. T.; Morgan, K. M.

    2017-12-01

    Given the severity of the 2016 global bleaching event, there are major questions about how quickly reef communities will recover. Here, we explore the ecological and physical structural changes that occurred across five atoll interior reefs in the southern Maldives using data collected at 6 and 12 months post-bleaching. Following initial severe coral mortality, further minor coral mortality had occurred by 12 months post-bleaching, and coral cover is now low (<6%). In contrast, reef rugosity has continued to decline over time, and our observations suggest transitions to rubble-dominated states will occur in the near future. Juvenile coral densities in shallow fore-reef habitats are also exceptionally low (<6 individuals m-2), well below those measured 9-12 months following the 1998 bleaching event, and below recovery thresholds identified on other Indian Ocean reefs. Our findings suggest that the physical structure of these reefs will need to decline further before effective recruitment and recovery can begin.

  19. NOAA's Coral Reef Conservation Program: 2016 Projects Monitoring the Effects of Thermal Stress on Coral Bleaching

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Climate change impacts have been identified as one of the greatest global threats to coral reef ecosystems. As temperature rise, mass bleaching, and infectious...

  20. Reconstruction of geomagnetic activity and near-Earth interplanetary conditions over the past 167 yr – Part 4: Near-Earth solar wind speed, IMF, and open solar flux

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    2014-04-01

    Full Text Available In the concluding paper of this tetralogy, we here use the different geomagnetic activity indices to reconstruct the near-Earth interplanetary magnetic field (IMF and solar wind flow speed, as well as the open solar flux (OSF from 1845 to the present day. The differences in how the various indices vary with near-Earth interplanetary parameters, which are here exploited to separate the effects of the IMF and solar wind speed, are shown to be statistically significant at the 93% level or above. Reconstructions are made using four combinations of different indices, compiled using different data and different algorithms, and the results are almost identical for all parameters. The correction to the aa index required is discussed by comparison with the Ap index from a more extensive network of mid-latitude stations. Data from the Helsinki magnetometer station is used to extend the aa index back to 1845 and the results confirmed by comparison with the nearby St Petersburg observatory. The optimum variations, using all available long-term geomagnetic indices, of the near-Earth IMF and solar wind speed, and of the open solar flux, are presented; all with ±2σ uncertainties computed using the Monte Carlo technique outlined in the earlier papers. The open solar flux variation derived is shown to be very similar indeed to that obtained using the method of Lockwood et al. (1999.

  1. DISCUS Ninth Grade, Earth Science.

    Science.gov (United States)

    Duval County School Board, Jacksonville, FL. Project DISCUS.

    Included are instructional materials designed for use with disadvantaged students who have a limited reading ability and poor command of English. The guide is the first volume of a two volume, one year program in earth science, and contains these four units and activities: Earth Materials, 8 activities; Weather, 10 activities; Water, 4 activities;…

  2. Short-term coral bleaching is not recorded by skeletal boron isotopes.

    Science.gov (United States)

    Schoepf, Verena; McCulloch, Malcolm T; Warner, Mark E; Levas, Stephen J; Matsui, Yohei; Aschaffenburg, Matthew D; Grottoli, Andréa G

    2014-01-01

    Coral skeletal boron isotopes have been established as a proxy for seawater pH, yet it remains unclear if and how this proxy is affected by seawater temperature. Specifically, it has never been directly tested whether coral bleaching caused by high water temperatures influences coral boron isotopes. Here we report the results from a controlled bleaching experiment conducted on the Caribbean corals Porites divaricata, Porites astreoides, and Orbicella faveolata. Stable boron (δ11B), carbon (δ13C), oxygen (δ18O) isotopes, Sr/Ca, Mg/Ca, U/Ca, and Ba/Ca ratios, as well as chlorophyll a concentrations and calcification rates were measured on coral skeletal material corresponding to the period during and immediately after the elevated temperature treatment and again after 6 weeks of recovery on the reef. We show that under these conditions, coral bleaching did not affect the boron isotopic signature in any coral species tested, despite significant changes in coral physiology. This contradicts published findings from coral cores, where significant decreases in boron isotopes were interpreted as corresponding to times of known mass bleaching events. In contrast, δ13C and δ18O exhibited major enrichment corresponding to decreases in calcification rates associated with bleaching. Sr/Ca of bleached corals did not consistently record the 1.2°C difference in seawater temperature during the bleaching treatment, or alternatively show a consistent increase due to impaired photosynthesis and calcification. Mg/Ca, U/Ca, and Ba/Ca were affected by coral bleaching in some of the coral species, but the observed patterns could not be satisfactorily explained by temperature dependence or changes in coral physiology. This demonstrates that coral boron isotopes do not record short-term bleaching events, and therefore cannot be used as a proxy for past bleaching events. The robustness of coral boron isotopes to changes in coral physiology, however, suggests that reconstruction of

  3. The impact of iron on the bleaching efficacy of hydrogen peroxide in liquid whey systems.

    Science.gov (United States)

    Jervis, Suzanne M; Drake, MaryAnne

    2013-02-01

    Whey is a value-added product that is utilized in many food and beverage applications for its nutritional and functional properties. Whey and whey products are generally utilized in dried ingredient applications. One of the primary sources of whey is from colored Cheddar cheese manufacture that contains the pigment annatto resulting in a characteristic yellow colored Cheddar cheese. The colorant is also present in the liquid cheese whey and must be bleached so that it can be used in ingredient applications without imparting a color. Hydrogen peroxide and benzoyl peroxide are 2 commercially approved chemical bleaching agents for liquid whey. Concerns regarding bleaching efficacy, off-flavor development, and functionality changes have been previously reported for whey bleached with hydrogen peroxide and benzoyl peroxide. It is very important for the dairy industry to understand how bleaching can impact flavor and functionality of dried ingredients. Currently, the precise mechanisms of off-flavor development and functionality changes are not entirely understood. Iron reactions in a bleached liquid whey system may play a key role. Reactions between iron and hydrogen peroxide have been widely studied since the reaction between these 2 relatively stable species can cause great destruction in biological and chemical systems. The actual mechanism of the reaction of iron with hydrogen peroxide has been a controversy in the chemistry and biological community. The precise mechanism for a given reaction can vary greatly based upon the concentration of reactants, temperature, pH, and addition of biological material. In this review, some hypotheses for the mechanisms of iron reactions that may occur in fluid whey that may impact bleaching efficacy, off-flavor development, and changes in functionality are presented. Cheese whey is bleached to remove residual carotenoid cheese colorant. Concerns regarding bleaching efficacy, off-flavor development, and functionality changes have

  4. The effect of bleaching agent on the flavor of liquid whey and whey protein concentrate.

    Science.gov (United States)

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

    2009-12-01

    The increasing use and demand for whey protein as an ingredient requires a bland-tasting, neutral-colored final product. The bleaching of colored Cheddar whey is necessary to achieve this goal. Currently, hydrogen peroxide (HP) and benzoyl peroxide (BPO) are utilized for bleaching liquid whey before spray drying. There is no current information on the effect of the bleaching process on the flavor of spray-dried whey protein concentrate (WPC). The objective of this study was to characterize the effect of bleaching on the flavor of liquid and spray-dried Cheddar whey. Cheddar cheeses colored with water-soluble annatto were manufactured in duplicate. Four bleaching treatments (HP, 250 and 500 mg/kg and BPO, 10 and 20 mg/kg) were applied to liquid whey for 1.5 h at 60 degrees C followed by cooling to 5 degrees C. A control whey with no bleach was also evaluated. Flavor of the liquid wheys was evaluated by sensory and instrumental volatile analysis. One HP treatment and one BPO treatment were subsequently selected and incorporated into liquid whey along with an unbleached control that was processed into spray-dried WPC. These trials were conducted in triplicate. The WPC were evaluated by sensory and instrumental analyses as well as color and proximate analyses. The HP-bleached liquid whey and WPC contained higher concentrations of oxidation reaction products, including the compounds heptanal, hexanal, octanal, and nonanal, compared with unbleached or BPO-bleached liquid whey or WPC. The HP products were higher in overall oxidation products compared with BPO samples. The HP liquid whey and WPC were higher in fatty and cardboard flavors compared with the control or BPO samples. Hunter CIE Lab color values (L*, a*, b*) of WPC powders were distinct on all 3 color scale parameters, with HP-bleached WPC having the highest L* values. Hydrogen peroxide resulted in a whiter WPC and higher off-flavor intensities; however, there was no difference in norbixin recovery between HP

  5. Understanding the Nature and Reactivity of Residual Lignin for Improved Pulping and Bleaching Efficiency; FINAL

    International Nuclear Information System (INIS)

    Yuan-Zong Lai

    2001-01-01

    One of the most formidable challenges in kraft pulping to produce bleached chemical pulps is how to effectively remove the last 5-10% of lignin while maintaining the fiber quality. To avoid a severe fiber degradation, kraft pulping is usually terminated in the 25-30 kappa number range and then followed by an elementally chlorine free (ECF) or a totally chlorine free (TCF) bleaching sequence to reduce the environmental impacts

  6. Effects of staining and bleaching on color change of dental composite resins.

    Science.gov (United States)

    Villalta, Patricia; Lu, Huan; Okte, Zeynep; Garcia-Godoy, Franklin; Powers, John M

    2006-02-01

    Discoloration of resin-based composites by colored solutions is a common problem. The use of bleaching agents for discolored natural teeth is becoming increasingly popular. It is not clear if bleaching agents can remove the stain from composite resins. The purpose of this study was to investigate the effects of 2 staining solutions and 3 bleaching systems on the color changes of 2 dental composite resins. Forty-five disk-shaped specimens (9 x 2.5 mm) of each of 2 composite resins, Filtek Supreme (FS) and Esthet X (EX), were prepared. The specimens were then divided into 3 groups of 15 specimens each and immersed in 2 staining solutions (coffee or red wine) or distilled water (control) for 3 hours daily over a 40-day test period. The 3 groups were then divided into 3 subgroups (n = 5), and 3 bleaching agents (Crest Night Effects, Colgate Simply White Night, or Opalescence Quick) were applied to the surface of the specimens over a 14-day period. Color of the specimens was measured with a spectrophotometer using CIELAB color space relative to CIE standard illuminant D55 at baseline, after staining, and after bleaching. The color differences (deltaE(ab)*) between the 3 measurements were calculated. The value deltaE(ab)* = 3.3 was used as an acceptable value in subjective visual evaluations. Analysis of variance and nonparametric analysis (Kruskal-Wallis test and Mann-Whitney test) were used to analyze the data. After staining, FS had more color change than EX and was more affected by the wine solution. After bleaching, the color of both EX and FS specimens returned to the baseline. The color differences between bleaching and baseline were less than value deltaE(ab)* = 3.3 for all groups. The nanocomposite (FS) changed color more than the microhybrid composite (EX) as a result of staining in coffee or red wine solutions. After bleaching, discoloration was removed completely from the composite resins tested.

  7. Understanding the Nature and Reactivity of Residual Lignin for Improved Pulping and Bleaching Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Yuan-Zong Lai

    2001-11-30

    One of the most formidable challenges in kraft pulping to produce bleached chemical pulps is how to effectively remove the last 5-10% of lignin while maintaining the fiber quality. To avoid a severe fiber degradation, kraft pulping is usually terminated in the 25-30 kappa number range and then followed by an elementally chlorine free (ECF) or a totally chlorine free (TCF) bleaching sequence to reduce the environmental impacts.

  8. Study on the Modification of Bleached Eucalyptus Kraft Pulp Using Birch Xylan

    Science.gov (United States)

    Wenjia Han; Chuanshan Zhao; Thomas Elder; Rendang Yang; Dongho Kim; Yunqiao Pu; Jeffery Hsieh; Arthur J. Ragauskas

    2012-01-01

    In this study, birch xylan was deposited onto elementally chlorine free (ECF) bleached eucalyptus kraft pulp, and the corresponding changes in physical properties were determined. An aqueous 5% birch xylan solution at pH 9 was added to 5 wt% slurry of bleached kraft eucalyptus fibers, with stirring at 70 C for 15 min after which the pH was adjusted to 5–6. The xylan...

  9. 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.

  10. Photoconductivity and bleaching of trapped electrons at 770C in irradiated methylcyclohexane

    International Nuclear Information System (INIS)

    Dolivo, G.; Gaeumann, T.

    1977-01-01

    The influence of the wavelength and intensity of the bleaching radiation on the thermoluminescence, thermoconductivity, optical absorption and photoconductivity of the methylcyclohexane, protonated and deuterated, was studied. The energy level scheme of the trapped electron in this alkane is very similar to that found in MTHF and 3-MP. The rate of bleaching of the trapped electrons is less in the deuterated product. (U.K.)

  11. Predicting Heat Stress to Inform Reef Management: NOAA Coral Reef Watch's 4-Month Coral Bleaching Outlook

    OpenAIRE

    Gang Liu; Gang Liu; C. Mark Eakin; Mingyue Chen; Arun Kumar; Jacqueline L. De La Cour; Jacqueline L. De La Cour; Scott F. Heron; Scott F. Heron; Scott F. Heron; Erick F. Geiger; Erick F. Geiger; William J. Skirving; William J. Skirving; Kyle V. Tirak

    2018-01-01

    The U.S. National Oceanic and Atmospheric Administration's (NOAA) Coral Reef Watch (CRW) operates a global 4-Month Coral Bleaching Outlook system for shallow-water coral reefs in collaboration with NOAA's National Centers for Environmental Prediction (NCEP). The Outlooks are generated by applying the algorithm used in CRW's operational satellite coral bleaching heat stress monitoring, with slight modifications, to the sea surface temperature (SST) predictions from NCEP's operational Climate F...

  12. High-resolution modeling of thermal thresholds and environmental influences on coral bleaching for local and regional reef management.

    Science.gov (United States)

    Kumagai, Naoki H; Yamano, Hiroya

    2018-01-01

    Coral reefs are one of the world's most threatened ecosystems, with global and local stressors contributing to their decline. Excessive sea-surface temperatures (SSTs) can cause coral bleaching, resulting in coral death and decreases in coral cover. A SST threshold of 1 °C over the climatological maximum is widely used to predict coral bleaching. In this study, we refined thermal indices predicting coral bleaching at high-spatial resolution (1 km) by statistically optimizing thermal thresholds, as well as considering other environmental influences on bleaching such as ultraviolet (UV) radiation, water turbidity, and cooling effects. We used a coral bleaching dataset derived from the web-based monitoring system Sango Map Project, at scales appropriate for the local and regional conservation of Japanese coral reefs. We recorded coral bleaching events in the years 2004-2016 in Japan. We revealed the influence of multiple factors on the ability to predict coral bleaching, including selection of thermal indices, statistical optimization of thermal thresholds, quantification of multiple environmental influences, and use of multiple modeling methods (generalized linear models and random forests). After optimization, differences in predictive ability among thermal indices were negligible. Thermal index, UV radiation, water turbidity, and cooling effects were important predictors of the occurrence of coral bleaching. Predictions based on the best model revealed that coral reefs in Japan have experienced recent and widespread bleaching. A practical method to reduce bleaching frequency by screening UV radiation was also demonstrated in this paper.

  13. Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite "Earth-plus".

    Science.gov (United States)

    Kasuga, Eriko; Kawakami, Yoshiyuki; Matsumoto, Takehisa; Hidaka, Eiko; Oana, Kozue; Ogiwara, Naoko; Yamaki, Dai; Sakurada, Tsukasa; Honda, Takayuki

    2011-01-01

    Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite "Earth-plus". Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains. The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log(10) colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3-6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours. Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric.

  14. Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”

    Science.gov (United States)

    Kasuga, Eriko; Kawakami, Yoshiyuki; Matsumoto, Takehisa; Hidaka, Eiko; Oana, Kozue; Ogiwara, Naoko; Yamaki, Dai; Sakurada, Tsukasa; Honda, Takayuki

    2011-01-01

    Background Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”. Methods Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains. Results The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log10 colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3–6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours. Conclusion Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric. PMID:21931489

  15. 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 brushing using either bleaching 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.

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

    Directory of Open Access Journals (Sweden)

    Janaina Freitas BORTOLATTO

    2016-01-01

    Full Text Available Abstract 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 < 0.001. Tooth brushing using either bleaching 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.

  17. 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

  18. Effect of delaying toothbrushing during bleaching on enamel surface roughness: an in vitro study.

    Science.gov (United States)

    Navimipour, E J; Mohammadi, N; Mostafazadeh, S; Ghojazadeh, M; Oskoee, P A

    2013-01-01

    This study aimed to evaluate the effect of toothbrushing on enamel surface roughness at three different intervals after daily bleaching treatment. Eighty enamel slabs were initially evaluated for surface roughness and then randomly divided into four groups. The bleaching procedure was carried out for 21 days, six hours daily. In the control group (group 1), the specimens were not brushed after bleaching, but in groups 2-4, they were brushed with toothpaste immediately, one hour, or two hours after bleaching, respectively. Then the specimens were stored in artificial saliva. Enamel surface roughness was reevaluated at the end of the period. Kruskal-Wallis and Mann-Whitney U tests showed statistically significant differences in the means of surface roughness values between the immediately brushed group and the three other groups (ptoothbrushing immediately after bleaching increased enamel surface roughness; however, postponing the procedure for one or two hours after daily bleaching and exposing the specimens to artificial saliva during the study period resulted in enamel surface roughness comparable to that of the control group.

  19. Improved microscopical detection of acid-fast bacilli by the modified bleach method in lymphnode aspirates

    Directory of Open Access Journals (Sweden)

    Annam Vamseedhar

    2009-07-01

    Full Text Available Objectives: To improve the smear microscopy for detection of acid-fast bacilli (AFB in fine needle aspiration cytology (FNAC of lymph node using the bleach method and also to compare this with cytological diagnosis and the conventional Ziehl-Neelsen (ZN method. Study Design: In 99 consecutive patients with clinical suspicion of tuberculosis (TB presenting with lymphadenopathy, FNACs were performed. Smears from the aspirates were processed for routine cytology and the conventional ZN method. The remaining material in the needle hub and/or the syringe was used for the bleach method. The significance of the bleach method over the conventional ZN method and cytology was analyzed using the χ2 test. Results: Of 99 aspirates, 93 were studied and the remaining six were excluded from the study due to diagnosis of malignancy in 4.04% (4/6 and inadequate aspiration in 2.02% (2/6. Among the 93 aspirates, 33.33% (31/93 were positive for AFB on conventional ZN method, 41.94% (39/93 were indicative of TB on cytology and the smear positivity increased to 63.44% (59/93 on bleach method. Conclusion: The bleach method is simple, inexpensive and potent disinfectant, also limiting the risk of laboratory-acquired infections. The implementation of the bleach method clearly improves microscopic detection and can be a useful contribution to routine cytology.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Effect of Bleaching Gels on Surface Roughness of Nanofilled Composite Resins

    Science.gov (United States)

    Wang, Linda; Francisconi, Luciana Fávaro; Atta, Maria Teresa; dos Santos, Jean Rodrigo; Del Padre, Natália Coelho; Gonini, Alcides; Fernandes, Karen Barros Parron

    2011-01-01

    Objectives: The aim of this study was to investigate the superficial texture of composite restorations after different bleaching protocols. Methods: Filtek Supreme (S), Filtek Z350 (F), and Grandio (G) were compared to Opallis (O) and Filtek Z250 (Z) (control microhybrid composites) and to bovine enamel using three different bleaching agents: 35% hydrogen peroxide Whiteness HP (WHP), 35% Whiteness HP MAXX (WMAXX) and 16% carbamide peroxide Whiteness Standard (WS). Six specimens from each composite were treated using each bleaching agent, according to the manufacturers’ instructions. Three random sites were measured for superficial roughness (Hommel Tester T 1000) weekly for each sample. Data were analyzed for each bleaching system using two-way ANOVA and Bonferroni tests at 5% significance level. Results: WHP treatment significantly altered the Filtek Supreme composite over time. When WMAXX was used, Grandio displayed the most significant alterations in surface roughness throughout the evaluation period, which was not observed for the other nanocomposites. Using WS, Filtek Z250 presented significant surface alterations over time, which was not seen in the nanofilled materials. Conclusions: Surface roughness alteration was material and time-dependent. The bleaching gels affected nanofilled and microhybrid composite resins. Enamel was the surface less affected by bleaching. PMID:21494385

  2. Effect of Home Bleaching on Microleakage of Fiber-reinforced and Particle-filled Composite Resins

    Directory of Open Access Journals (Sweden)

    Farahnaz Sharafeddin

    2013-12-01

    Full Text Available Background and aims. Bleaching may exert some negative effects on existing composite resin restorations. The aim of this study was to evaluate the effect of home bleaching on microleakage of fiber-reinforced and particle-filled composite resins. Materials and methods. Ninety class V cavities (1.5×2×3 mm were prepared on the buccal surfaces of 90 bovine teeth. The teeth were randomly divided into 6 groups (n=15 and restored as follows: Groups 1 and 2 with Z100, groups 3 and 4 with Z250, and groups 5 and 6 with Nulite F composite resins. All the specimens were thermocycled. Groups 1, 3 and 5 were selected as control groups (without bleaching and the experimental groups 2, 4 and 6 were bleached with 22% carbamide peroxide gel. All the samples were immersed in 2% basic fuchsin dye for 24 hours and then sectioned longitudinally. Dye penetration was evaluated under a stereomicroscope (×25, at both the gingival and incisal margins. Data were analyzed using Kruskal-Wallis, Mann-Whitney and Wilcoxon tests (α=0.05. Results. Statistical analyses revealed that bleaching gel increased microleakage only at gingival margins with Z250 (P=0.007. Moreover, the control groups showed a statistically significant difference in microleakage at their gingival margins. Nulite F had the maximum microleakage while Z250 showed the minimum (P=0.006. Conclusion. Microleakage of home-bleached restorations might be related to the type of composite resin used.

  3. Graded changes in enamel component volumes resulted from a short tooth bleaching procedure.

    Science.gov (United States)

    Ferreira, Artemisa Fernanda Moura; Perez, Flávia Maria de Moraes Ramos; Limeira Júnior, Francisco de Assis; de Moura, Mirella de Fátima Liberato; de Sousa, Frederico Barbosa

    2016-05-01

    To test the hypothesis that changes in enamel component volumes (mineral, organic, and water volumes, and permeability) are graded from outer to inner enamel after a short bleaching procedure. Extracted unerupted human third molars had half of their crowns bleached (single bleaching session, 3 × 15 min), and tooth shade changes in bleached parts were analyzed with a spectrophotometer. Ground sections were prepared, component volumes and permeability were quantified at histological points located at varying distances from the enamel surface (n=10 points/location), representing conditions before and after bleaching. Tooth shade changes were significant (pvolume (in decreasing order of relevance: mineral loss, organic gain, water gain, and decrease in permeability) with the set of distances from the enamel surface (graded from the enamel surface inward) (canonical R(2)=0.97; p99%). Changes in enamel composition after a short bleaching procedure followed a gradient within component volumes (mineral loss>organic gain>water gain>decrease in permeability) and decreased from the enamel surface inward. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Proteomic analysis of bleached and unbleached Acropora palmata, a threatened coral species of the Caribbean.

    Science.gov (United States)

    Ricaurte, Martha; Schizas, Nikolaos V; Ciborowski, Pawel; Boukli, Nawal M

    2016-06-15

    There has been an increase in the scale and frequency of coral bleaching around the world due mainly to changes in sea temperature. This may occur at large scales, often resulting in significant decline in coral coverage. In order to understand the molecular and cellular basis of the ever-increasing incidence of coral bleaching, we have undertaken a comparative proteomic approach with the endangered Caribbean coral Acropora palmata. Using a proteomic tandem mass spectrometry approach, we identified 285 and 321 expressed protein signatures in bleached and unbleached A. palmata colonies, respectively, in southwestern Puerto Rico. Overall the expression level of 38 key proteins was significantly different between bleached and unbleached corals. A wide range of proteins was detected and categorized, including transcription factors involved mainly in heat stress/UV responses, immunity, apoptosis, biomineralization, the cytoskeleton, and endo-exophagocytosis. The results suggest that for bleached A. palmata, there was an induced differential protein expression response compared with those colonies that did not bleach under the same environmental conditions. Published by Elsevier Ltd.

  5. Transcriptomic responses to darkness stress point to common coral bleaching mechanisms

    Science.gov (United States)

    Desalvo, M. K.; Estrada, A.; Sunagawa, S.; Medina, Mónica

    2012-03-01

    Coral bleaching occurs in response to numerous abiotic stressors, the ecologically most relevant of which is hyperthermic stress due to increasing seawater temperatures. Bleaching events can span large geographic areas and are currently a salient threat to coral reefs worldwide. Much effort has been focused on understanding the molecular and cellular events underlying bleaching, and these studies have mainly utilized heat and light stress regimes. In an effort to determine whether different stressors share common bleaching mechanisms, we used complementary DNA (cDNA) microarrays for the corals Acropora palmata and Montastraea faveolata (containing >10,000 features) to measure differential gene expression during darkness stress. Our results reveal a striking transcriptomic response to darkness in A. palmata involving chaperone and antioxidant up-regulation, growth arrest, and metabolic modifications. As these responses were previously measured during thermal stress, our results suggest that different stressors may share common bleaching mechanisms. Furthermore, our results point to hypoxia and endoplasmic reticulum stress as critical cellular events involved in molecular bleaching mechanisms. On the other hand, we identified a meager transcriptomic response to darkness in M. faveolata where gene expression differences between host colonies and sampling locations were greater than differences between control and stressed fragments. This and previous coral microarray studies reveal the immense range of transcriptomic responses that are possible when studying two coral species that differ greatly in their ecophysiology, thus pointing to the importance of comparative approaches in forecasting how corals will respond to future environmental change.

  6. Patient and environmental service employee satisfaction of using germicidal bleach wipes for patient room cleaning.

    Science.gov (United States)

    Aronhalt, Kimberly C; McManus, James; Orenstein, Robert; Faller, Rebecca; Link, Mary

    2013-01-01

    More healthcare institutions are using bleach products which are sporicidal to reduce Clostridium difficile infection (CDI). There may be patient and employee concerns about the appearance of bleach residue left on surfaces, odors, and respiratory tract irritation. The intervention used bleach wipes for daily and terminal patient room cleaning to reduce transmission of CDI and was implemented on patient care units with a relatively high incidence of CDI. Both patients and Environmental Services (ES) staff were surveyed to assess their satisfaction of the bleach wipe product used during room cleaning. Patients (n = 94) (91%) continued to be very satisfied with how well their rooms were cleaned every day. Bleach wipes were well tolerated by patients (n = 44) (100%) surveyed on the medical units and less tolerated by patients (n = 50) (22%) on the hematology-oncology units. ES staff (6) reported less satisfaction and more respiratory irritation from using the bleach wipes; however, later their satisfaction improved. © 2012 National Association for Healthcare Quality.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  8. Rare-earth and thorium in soil and manioc: determination using neutron activation analysis; Terras-raras e torio em solo e mandioca: determinacao por ativacao neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Lucilene Guerra e [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Faculdade de Farmacia; Menezes, Maria Angela de B.C.; Palmieri, Helena E.L. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil). Servico de Reator e Irradiacoes]. E-mail: menezes@cdtn.br; Nalini Junior, Herminio A. [Ouro Preto Univ., MG (Brazil). Dept. de Geologia; Jacimivic, Radojko [Instituto Josef Stefan, Liubliana (Slovenia). Dept. de Ciencias Ambientais

    2005-07-01

    This paper reports the elements rare-earth and Thorium determined in soil and manioc during an assessment carried out to evaluate the elemental concentration in several matrixes connected with the chain food. One site studied is in the Iron Quadrangle, Minas Gerais, Brazil, that presented mineral exploration activity in the past. Another site is without any mining activity and it is outside the Quadrangle. The objective was to evaluate the influence of a mining activity on the elemental concentration in the soil and manioc is grown around the mining area. The elemental determination was achieved by applying the k{sub 0}-instrumental Neutron Activation. (author)

  9. Clareamento gengival: ensino e etnocentrismo Gingival bleaching: teaching and ethnocentrism

    Directory of Open Access Journals (Sweden)

    Edson Daruich Bolla

    2010-06-01

    Full Text Available O estudo objetivou identificar os padrões de estética bucal/gengival subjacentes à formação e prática profissional do cirurgião-dentista, na perspectiva do etnocentrismo. A partir da análise documental e da realização de entrevistas (semiestruturadas com cirurgiões dentistas formados há dez ou mais anos, o estudo recorreu a uma abordagem qualitativa, ancorada na análise temática. No âmbito do ensino da periodontia, o estudo evidenciou que a presença da pigmentação fisiológica é omitida ou tratada como uma alteração de normalidade e/ou antiestética. Todos os entrevistados aprenderam a realizar o clareamento gengival em nível de pós-graduação, sendo estimulados a ofertar tal procedimento em nome de um sorriso saudável e bonito. Diante da supervalorização da eficiência da técnica, ressalta a ausência da discussão da questão estética na perspectiva étnica. Parece que a oferta do clareamento gengival se faz norteada pelo padrão branco de beleza, evidenciando o caráter etnocêntrico do procedimento.The aim of this study was to identify buccal/gingival cosmetic dentistry patterns subjacent to formation and professional practice of the dental surgeon from the ethnocentrism point of view. This is an exploratory study with a qualitative approach based on the thematic analysis. Initially a documental analysis was carried out. Thereafter, dental surgeons were interviewed and semi-structured questions were applied. In the Periodontal teaching field, this study showed that the presence of racial melanosis is omitted or treated as an alteration in the normality patterns and it is considered anti-aesthetic. All the interviewers learnt how to practice gingival bleaching in the post-graduation courses, they were all encouraged to offer this cosmetic dentistry procedure with the opportunity of obtaining a beautiful and healthy smile, thus assuring the belief of the Caucasian racial aesthetic superiority. This study make us

  10. Earth Science Informatics - Overview

    Science.gov (United States)

    Ramapriyan, H. K.

    2017-01-01

    Over the last 10-15 years, significant advances have been made in information management, there are an increasing number of individuals entering the field of information management as it applies to Geoscience and Remote Sensing data, and the field of informatics has come to its own. Informatics is the science and technology of applying computers and computational methods to the systematic analysis, management, interchange, and representation of science data, information, and knowledge. Informatics also includes the use of computers and computational methods to support decision making and applications. Earth Science Informatics (ESI, a.k.a. geoinformatics) is the application of informatics in the Earth science domain. ESI is a rapidly developing discipline integrating computer science, information science, and Earth science. Major national and international research and infrastructure projects in ESI have been carried out or are on-going. Notable among these are: the Global Earth Observation System of Systems (GEOSS), the European Commissions INSPIRE, the U.S. NSDI and Geospatial One-Stop, the NASA EOSDIS, and the NSF DataONE, EarthCube and Cyberinfrastructure for Geoinformatics. More than 18 departments and agencies in the U.S. federal government have been active in Earth science informatics. All major space agencies in the world, have been involved in ESI research and application activities. In the United States, the Federation of Earth Science Information Partners (ESIP), whose membership includes over 180 organizations (government, academic and commercial) dedicated to managing, delivering and applying Earth science data, has been working on many ESI topics since 1998. The Committee on Earth Observation Satellites (CEOS)s Working Group on Information Systems and Services (WGISS) has been actively coordinating the ESI activities among the space agencies.The talk will present an overview of current efforts in ESI, the role members of IEEE GRSS play, and discuss

  11. Resources to Transform Undergraduate Geoscience Education: Activities in Support of Earth, Oceans and Atmospheric Sciences Faculty, and Future Plans

    Science.gov (United States)

    Ryan, J. G.; Singer, J.

    2013-12-01

    The NSF offers funding programs that support geoscience education spanning atmospheric, oceans, and Earth sciences, as well as environmental science, climate change and sustainability, and research on learning. The 'Resources to Transform Undergraduate Geoscience Education' (RTUGeoEd) is an NSF Transforming Undergraduate Education in STEM (TUES) Type 2 special project aimed at supporting college-level geoscience faculty at all types of institutions. The project's goals are to carry out activities and create digital resources that encourage the geoscience community to submit proposals that impact their courses and classroom infrastructure through innovative changes in instructional practice, and contribute to making transformative changes that impact student learning outcomes and lead to other educational benefits. In the past year information sessions were held during several national and regional professional meetings, including the GSA Southeastern and South-Central Section meetings. A three-day proposal-writing workshop for faculty planning to apply to the TUES program was held at the University of South Florida - Tampa. During the workshop, faculty learned about the program and key elements of a proposal, including: the need to demonstrate awareness of prior efforts within and outside the geosciences and how the proposed project builds upon this knowledge base; need to fully justify budget and role of members of the project team; project evaluation and what matters in selecting a project evaluator; and effective dissemination practices. Participants also spent time developing their proposal benefitting from advice and feedback from workshop facilitators. Survey data gathered from workshop participants point to a consistent set of challenges in seeking grant support for a desired educational innovation, including poor understanding of the educational literature, of available funding programs, and of learning assessment and project evaluation. Many also noted

  12. Impact of a longitudinal community HIV intervention targeting injecting drug users' stage of change for condom and bleach use.

    Science.gov (United States)

    Jamner, M S; Wolitski, R J; Corby, N H

    1997-01-01

    To evaluate the impact of the Long Beach AIDS Community Demonstration Project, a community-based HIV-prevention intervention incorporating principles from the Transtheoretical model in its design and evaluation. Repeated cross-sectional sampling with matched intervention and comparison communities. Neighborhoods in Long Beach, California, having a high prevalence of drug abuse and prostitution. 3081 injecting drug users who were sexually active and/or shared injection equipment. Trained peer volunteers distributed fliers featuring role model stories targeted to the population's stage of change. Fliers were packaged with bleaching kits and/or condoms. Primary outcome measures were exposure to the intervention, condom carrying, and stage of change for disinfecting injection equipment with bleach and for using condoms with main and other partners. Toward the end of the study, 77% of injection drug users in the intervention area reported being exposed to the intervention. In the intervention area, rates of condom carrying increased from 10 to 27% (p project exposure had higher stage-of-change scores for using condoms with a main partner (p Project intervention for reaching injecting drug users in the community and for motivating the adoption of risk-reducing practices.

  13. A method for defleshing human remains using household bleach.

    Science.gov (United States)

    Mann, Robert W; Berryman, Hugh E

    2012-03-01

    Medical examiners and forensic anthropologists are often faced with the difficult task of removing soft tissue from the human skeleton without damaging the bones, teeth and, in some cases, cartilage. While there are a number of acceptable methods that can be used to remove soft tissue including macerating in water, simmering or boiling, soaking in ammonia, removing with scissors, knife, scalpel or stiff brush, and dermestid beetles, each has its drawback in time, safety, or potential to damage bone. This technical report using the chest plate of a stabbing victim presents a safe and effective alternative method for removing soft tissue from human remains, in particular the chest plate, following autopsy, without damaging or separating the ribs, sternum, and costal cartilage. This method can be used to reveal subtle blunt force trauma to bone, slicing and stabbing injuries, and other forms of trauma obscured by overlying soft tissue. Despite the published cautionary notes, when done properly household bleach (3-6% sodium hypochlorite) is a quick, safe, and effective method for examining cartilage and exposing skeletal trauma by removing soft tissue from human skeletal remains. 2011 American Academy of Forensic Sciences. Published 2011. This article is a U.S. Government work and is in the public domain in the U.S.A.

  14. Resilience and climate change: lessons from coral reefs and bleaching in the Western Indian Ocean

    Science.gov (United States)

    Obura, David O.

    2005-05-01

    The impact of climate change through thermal stress-related coral bleaching on coral reefs of the Western Indian Ocean has been well documented and is caused by rising sea water temperatures associated with background warming trends and extreme climate events. Recent studies have identified a number of factors that may reduce the impact of coral bleaching and mortality at a reef or sub-reef level. However, there is little scientific consensus as yet, and it is unclear how well current science supports the immediate needs of management responses to climate change. This paper provides evidence from the Western Indian Ocean in support of recent hypotheses on coral and reef vulnerability to thermal stress that have been loosely termed 'resistance and resilience to bleaching'. The paper argues for a more explicit definition of terms, and identifies three concepts affecting coral-zooxanthellae holobiont and reef vulnerability to thermal stress previously termed 'resistance to bleaching': 'thermal protection', where some reefs are protected from the thermal conditions that induce bleaching and/or where local physical conditions reduce bleaching and mortality levels; 'thermal resistance', where individual corals bleach to differing degrees to the same thermal stress; and 'thermal tolerance', where individual corals suffer differing levels of mortality when exposed to the same thermal stress. 'Resilience to bleaching' is a special case of ecological resilience, where recovery following large-scale bleaching mortality varies according to ecological and other processes. These concepts apply across multiple levels of biological organization and temporal and spatial scales. Thermal resistance and tolerance are genetic properties and may interact with environmental protection properties resulting in phenotypic variation in bleaching and mortality of corals. The presence or absence of human threats and varying levels of reef management may alter the influence of the above factors

  15. Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite "Earth-plus"

    Directory of Open Access Journals (Sweden)

    Kasuga E

    2011-09-01

    Full Text Available Eriko Kasuga1,2, Yoshiyuki Kawakami2,3, Takehisa Matsumoto1, Eiko Hidaka1, Kozue Oana2, Naoko Ogiwara1, Dai Yamaki4, Tsukasa Sakurada4, Takayuki Honda1,51Department of Laboratory Medicine, Shinshu University Hospital, 2Division of Infection Control and Microbiological Regulation, Department of Health and Medical Sciences, Shinshu University Graduate School of Medicine, 3Division of Clinical Microbiology, Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University School of Medicine, 4Shinshu Ceramics Co Ltd, Kiso, Nagano, Japan; 5Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, JapanBackground: Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite "Earth-plus".Methods: Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains.Results: The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log10 colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3–6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours.Conclusion: Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric.Keywords: hydroxyapatite

  16. Separation of rare earths by means of acid organophosphorous compounds. Structure-activity study by molecular simulation

    International Nuclear Information System (INIS)

    Fourcot, Fabrice

    1991-01-01

    The increasing number of industrial applications of rare earths has resulted in an increased demand in purified rare earths whereas their separation is difficult due to their high chemical similarity. The search for a better separation leads to the search for more selective extraction agents. Organophosphorous compounds appear to be the most selective. As the search for new extraction agents resulting in high lanthanide extraction efficiency or in a better selectivity between rare earths has been mainly empiric, this research thesis aims at developing a molecular simulation method which allows the number of molecules to be synthesized and tested to be reduced. After having briefly recalled general knowledge on liquid-liquid extraction and on rare earths, and described calculation methods (quantum methods, methods based on molecular mechanics, conformational analysis, methods of charge calculation), the author proposes a critical review of literature related to rare earth liquid-liquid extraction by organophosphorous acids with respect to the used extraction agent. The molecular modelling issue is then addressed by describing ways to apply it to extraction problems, faced problems, brought solutions and obtained results

  17. Nearshore Turbid-Zone Corals Exhibit High Bleaching Tolerance on the Great Barrier Reef Following the 2016 Ocean Warming Event

    OpenAIRE

    Morgan, Kyle M.; Perry, Chris T.; Johnson, Jamie A.; Smithers, Scott G.

    2017-01-01

    High sea surface temperatures (SSTs) on the Great Barrier Reef (GBR) during summer 2015/2016 caused extensive coral bleaching, with aerial and in-water surveys confirming high (but variable) bleaching-related coral mortality. In contrast, bleaching impacts on nearshore turbid-zone reefs, traditionally considered more “marginal” coral habitats, remain poorly documented. This is because rapid ecological surveys are difficult in these turbid water settings, and baseline coral community data from...

  18. Cell death and degeneration in the symbiotic\\ud dinoflagellates of the coral Stylophora pistillata\\ud during bleaching

    OpenAIRE

    Franklin, Daniel J.; Hoegh-Guldberg, O.; Jones, R.J.; Berges , John A.

    2004-01-01

    Rising sea temperatures are increasing the incidences of mass coral bleaching (the dissociation\\ud of the coral–algal symbiosis) and coral mortality. In this study, the effects of bleaching\\ud (induced by elevated light and temperature) on the condition of symbiotic dinoflagellates (Symbiodinium\\ud sp.) within the tissue of the hard coral Stylophora pistillata (Esper) were assessed using a suite\\ud of techniques. Bleaching of S. pistillata was accompanied by declines in the maximum potential\\...

  19. Human Expeditions to Near-Earth Asteroids: An Update on NASA's Status and Proposed Activities for Small Body Exploration

    Science.gov (United States)

    Abell, Paul; Mazanek, Dan; Barbee, Brent; Landis, Rob; Johnson, Lindley; Yeomans, Don; Reeves, David; Drake, Bret; Friedensen, Victoria

    2013-01-01

    Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth- Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. The scientific and hazard mitigation benefits, along with the programmatic and operational benefits of a human venture beyond the Earth-Moon system, make a mission to a NEA using NASA s proposed exploration systems a compelling endeavor.

  20. Massive hard coral loss after a severe bleaching event in 2010 at Los Roques, Venezuela

    Directory of Open Access Journals (Sweden)

    Carolina Bastidas

    2012-03-01

    Full Text Available Thermal anomalies have become more severe, frequent and well-documented across the Caribbean for the past 30 years. This increase in temperature has caused coral bleaching resulting in reef decline. At Los Roques National Park, Venezuela, temperature has been monitored at four reef sites. In mid-September 2010, seawater temperature reached 30.85°C at 5 m depth in Los Roques, an archipelago only slightly affected by previous bleaching events. For example, bleaching in Los Roques in 2005 was mild compared to the rest of the Caribbean and to the results in this study. In 2010, seawater temperatures remained above 29.0°C from mid-August until the first week of November, resulting in +16 Degree Heating Weeks by that time. Our annual survey of four reef sites indicated that 72% of 563 scleractinian colonies were partial or totally bleached (white or pale (discolored in October 2010. In February 2011, there were still 46% of coral colonies affected; but most of them were pale and only 2% were bleached. By February, coral cover had declined 4 to 30% per transect, with a mean of 14.3%. Thus, mean coral cover dropped significantly from 45 to 31% cover (a 34% reduction. In addition to bleaching, corals showed a high prevalence (up to 16% of black band disease in October 2010 and of white plague (11% in February 2011. As a consequence, coral mortality is expected to be larger than reported here. Reef surveys since 2002 and personal observations for more than 20 years indicated that this bleaching event and its consequences in Los Roques have no precedent. Our results suggest that reef sites with no previous record of significant deterioration are more likely to become affected by thermal anomalies. However, this archipelago is relatively unaffected by local anthropogenic disturbance and has a high coral recruitment, which may contribute to its recovery

  1. Effects of modeled tropical sea surface temperature variability on coral reef bleaching predictions

    Science.gov (United States)

    van Hooidonk, R.; Huber, M.

    2012-03-01

    Future widespread coral bleaching and subsequent mortality has been projected using sea surface temperature (SST) data derived from global, coupled ocean-atmosphere general circulation models (GCMs). While these models possess fidelity in reproducing many aspects of climate, they vary in their ability to correctly capture such parameters as the tropical ocean seasonal cycle and El Niño Southern Oscillation (ENSO) variability. Such weaknesses most likely reduce the accuracy of predicting coral bleaching, but little attention has been paid to the important issue of understanding potential errors and biases, the interaction of these biases with trends, and their propagation in predictions. To analyze the relative importance of various types of model errors and biases in predicting coral bleaching, various intra- and inter-annual frequency bands of observed SSTs were replaced with those frequencies from 24 GCMs 20th century simulations included in the Intergovernmental Panel on Climate Change (IPCC) 4th assessment report. Subsequent thermal stress was calculated and predictions of bleaching were made. These predictions were compared with observations of coral bleaching in the period 1982-2007 to calculate accuracy using an objective measure of forecast quality, the Peirce skill score (PSS). Major findings are that: (1) predictions are most sensitive to the seasonal cycle and inter-annual variability in the ENSO 24-60 months frequency band and (2) because models tend to understate the seasonal cycle at reef locations, they systematically underestimate future bleaching. The methodology we describe can be used to improve the accuracy of bleaching predictions by characterizing the errors and uncertainties involved in the predictions.

  2. Opposite latitudinal gradients in projected ocean acidification and bleaching impacts on coral reefs.

    Science.gov (United States)

    van Hooidonk, Ruben; Maynard, Jeffrey Allen; Manzello, Derek; Planes, Serge

    2014-01-01

    Coral reefs and the services they provide are seriously threatened by ocean acidification and climate change impacts like coral bleaching. Here, we present updated global projections for these key threats to coral reefs based on ensembles of IPCC AR5 climate models using the new Representative Concentration Pathway (RCP) experiments. For all tropical reef locations, we project absolute and percentage changes in aragonite saturation state (Ωarag) for the period between 2006 and the onset of annual severe bleaching (thermal stress >8 degree heating weeks); a point at which it is difficult to believe reefs can persist as we know them. Severe annual bleaching is projected to start 10-15 years later at high-latitude reefs than for reefs in low latitudes under RCP8.5. In these 10-15 years, Ωarag keeps declining and thus any benefits for high-latitude reefs of later onset of annual bleaching may be negated by the effects of acidification. There are no long-term refugia from the effects of both acidification and bleaching. Of all reef locations, 90% are projected to experience severe bleaching annually by 2055. Furthermore, 5% declines in calcification are projected for all reef locations by 2034 under RCP8.5, assuming a 15% decline in calcification per unit of Ωarag. Drastic emissions cuts, such as those represented by RCP6.0, result in an average year for the onset of annual severe bleaching that is ~20 years later (2062 vs. 2044). However, global emissions are tracking above the current worst-case scenario devised by the scientific community, as has happened in previous generations of emission scenarios. The projections here for conditions on coral reefs are dire, but provide the most up-to-date assessment of what the changing climate and ocean