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Light activated bleaching

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https://www.readbyqxmd.com/read/29159178/zinc-containing-hydroxyapatite-enhances-cold-light-activated-tooth-bleaching-treatment-in-vitro
#1
Yi Li, Xinchang Shi, Wei Li
Cold-light bleaching treatment has grown to be a popular tooth whitening procedure in recent years, but its side effect of dental enamel demineralization is a widespread problem. The aim of this study was to synthesize zinc-substituted hydroxyapatite as an effective biomaterial to inhibit demineralization or increase remineralization. We synthesized zinc-substituted hydroxyapatite containing different zinc concentrations and analysed the product using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and energy dispersive spectrometer (EDS)...
2017: BioMed Research International
https://www.readbyqxmd.com/read/29124118/chemical-analysis-and-evaluation-of-antioxidant-antimicrobial-and-photoprotective-activities-of-schinopsis-brasiliensis-engl-anacardiaceae
#2
Sarah Raquel Gomes de Lima-Saraiva, Fernanda Granja da Silva Oliveira, Raimundo Gonçalves de Oliveira Junior, Camila de Souza Araújo, Ana Paula de Oliveira, Alessandra Gomes Marques Pacheco, Larissa Araújo Rolim, Elba Lúcia Cavalcanti de Amorim, Francine Celise Siqueira César, Jackson Roberto Guedes da Silva Almeida
Schinopsis brasiliensis Engl. is a native plant of Caatinga which has high concentrations of compounds capable of absorbing ultraviolet light, suggesting its potential application for the development of sunscreen preparations. After its identification and collection, this vegetable drug was submitted to a physicochemical analysis through the preparation of ethanolic extract. The phytochemical screening and analysis of extracts were carried out by high-performance liquid chromatography (HPLC) evaluation. The antioxidant activity of the extract was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and β-carotene bleaching test...
2017: TheScientificWorldJournal
https://www.readbyqxmd.com/read/29048161/effects-of-temperature-and-concentration-on-the-rate-of-photobleaching-of-erythrosine-in-water
#3
Joshua K G Karlsson, Owen J Woodford, Roza Al-Aqar, Anthony Harriman
Erythrosine, a popular food dye, undergoes fast O2-sensitive bleaching in water when subjected to visible light illumination. In dilute solution, erythrosine undergoes photobleaching via first-order kinetics, where the rate of bleaching depends critically on the rate of photon absorption and on the concentration of dissolved oxygen. Kinetic studies indicate that this inherent bleaching is augmented by self-catalysis at higher concentrations of erythrosine and on long exposure times. Under the conditions used, bleaching occurs by way of geminate attack of singlet molecular oxygen on the chromophore...
November 1, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28933148/frequency-selective-photobleaching-as-a-route-to-chromatic-control-in-supramolecular-oled-devices
#4
Yu-Tang Tsai, Hsiang-Fang Liu, Bo-Ji Peng, Kuo-Pi Tseng, Ming-Cheng Kuo, Ken-Tsung Wong, Guillaume Wantz, Lionel Hirsch, Guillaume Raffy, Andre Del Guerzo, Dario M Bassani
We report a series of molecules that spontaneously self-organize into small electroluminescent domains of sub-micrometer dimensions when dissolved in tetrahydrofuran. The self-assembled spherical aggregates have an average diameter of 300 nm and exhibit efficient energy transfer from the blue to the green or red component. The aggregates can be chromatically addressed or patterned by selective bleaching of the energy-acceptor component using a laser source. This allows the fabrication of electroluminescence devices by directly photopatterning the active layer without the need of additional steps...
October 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28855837/in-vitro-cytotoxicity-and-cellular-uptake-studies-of-luminescent-functionalized-core-shell-nanospheres
#5
Anees A Ansari, T N Hasan, N A Syed, J P Labis, Ali A Alshatwi
Monodispersed luminescent functionalized core-shell nanospheres (LFCSNs) were successfully synthesized and investigated for their cyto-toxic effect on human liver hepatocellular carcinoma cell line (HepG2 cells) by adopting MTT, DNA Ladder, TUNEL assay and qPCR based gene expressions through mRNA quantifications. The TUNEL and DNA ladder assays suggested an insignificant apoptosis in HepG2 cells due to the LFCSNs treatment. Further, the qPCR results also show that the mRNA expressions of cell cycle checkpoint gene p53 and apoptosis related gene (caspase-9) was up-regulated, while the antiapoptotic gene BCl-2 and apoptosis related genes FADD and CAS-3 (apoptosis effecter gene) were down-regulated in the LFCSNs treated cells...
September 2017: Saudi Journal of Biological Sciences
https://www.readbyqxmd.com/read/28814729/thermally-induced-crystallization-hole-transport-nlo-and-photovoltaic-activity-of-a-bis-diarylamine-based-push-pull-molecule
#6
Yue Jiang, Magali Allain, Denis Gindre, Sylvie Dabos-Seignon, Philippe Blanchard, Clément Cabanetos, Jean Roncali
The synthesis of a molecule constituted of two diarylamine-based push-pull chromophores covalently linked via their nitrogen atom is described. Comparison of the electronic properties with the parent monomer shows that dimerization has negligible influence on the electronic properties of the molecule but exerts a dramatic impact on the capacity of the material to self-reorganize. Application of thermal annealing to thin films induces the crystallization under original morphologies, a process accompanied by a partial bleaching of the absorption in the visible range and by a huge increase of hole-mobility...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811302/effects-of-temperature-and-uvr-on-organic-matter-fluxes-and-the-metabolic-activity-of-acropora-muricata
#7
Lucile Courtial, Christine Ferrier-Pagès, Stéphan Jacquet, Riccardo Rodolfo-Metalpa, Stéphanie Reynaud, Cécile Rottier, Fanny Houlbrèque
Coral bleaching events are predicted to occur more frequently in the coming decades with global warming. The susceptibility of corals to bleaching during thermal stress episodes depends on many factors, including the magnitude of thermal stress and irradiance. The interactions among these two factors, and in particular with ultra-violet radiation (UVR), the most harmful component of light, are more complex than assumed, and are not yet well understood. This paper explores the individual and combined effects of temperature and UVR on the metabolism of Acropora muricata, one of the most abundant coral species worldwide...
August 15, 2017: Biology Open
https://www.readbyqxmd.com/read/28765671/evaluation-of-the-diode-laser-810nm-980-nm-on-color-change-of-teeth-after-external-bleaching
#8
Nazanin Kiomars, Pouneh Azarpour, Mansooreh Mirzaei, Sedighe Sadat Hashemi Kamangar, Mohammad Javad Kharazifard, Nasim Chiniforush
Subject and aim: The aim of this study was to evaluate the efficiency of diode laser-activated bleaching systems for color change of teeth. Materials & Methods: 40 premolars with intact enamel surfaces were selected for five external bleaching protocols (n=8). Two different wavelengths of diode laser (810 and 980 nm) with two different hydrogen peroxide concentrations (30% and 46%) were selected for laser bleaching. Group 1 received bleaching (Heydent- Germany) with a 810 nm diode laser; Group 2 received bleaching (Heydent- Germany) with a 980 nm diode laser; Group 3 received bleaching (laser white*20- Biolase) with a 810 nm diode laser; Group 4 received bleaching (laser white*20- Biolase) with a 980 nm diode laser, with an output power of 1...
December 30, 2016: Laser Therapy
https://www.readbyqxmd.com/read/28762354/a-comparison-of-various-minimally-invasive-techniques-for-the-removal-of-dental-fluorosis-stains-in-children
#9
Aarushi Gupta, Renuka Dhingra, Payal Chaudhuri, Anil Gupta
CONTEXT: Dental fluorosis is caused by successive exposure to high concentrations of fluoride during tooth development leading to enamel with lower mineral content and increased porosity. AIMS: The aim of the study was to evaluate and compare the effectiveness of minimally invasive techniques for the removal of dental fluorosis stains in children in vivo. DESIGN: Ninety children in the age group of 10-17 years were selected. MATERIALS AND METHODS: The study sample was equally and randomly divided into three groups; Group 1: In-office bleaching with 35% hydrogen peroxide (HP) activated by light-emitting diode (LED) bleaching unit (35% HP), Group 2: Enamel microabrasion (EM) followed by in-office bleaching with 44% carbamide peroxide gel (EM), Group 3: In-office bleaching with 5% sodium hypochlorite (5% NaOCl)...
July 2017: Journal of the Indian Society of Pedodontics and Preventive Dentistry
https://www.readbyqxmd.com/read/28712152/teeth-bleaching-with-low-concentrations-of-hydrogen-peroxide-6-and-catalyzed-by-led-blue-450%C3%A2-%C3%A2-%C3%A2-10-nm-and-laser-infrared-808%C3%A2-%C3%A2-%C3%A2-10-nm-light-for-in-office-treatment-randomized-clinical-trial-1-year-follow-up
#10
Patricio Vildósola, Jessica Bottner, Francisca Avalos, Isidora Godoy, Javier Martín, Eduardo Fernández
OBJECTIVES: The aim of this study was to evaluate color longevity after a year of in-office bleaching with gel (6% hydrogen peroxide HP, LED blue/laser infrared activation system) compared to a 35% control concentration in a split-mouth study model. MATERIALS AND METHODS: Thirty-one patients were initially treated. The bleaching procedure with 6% or 35% gel HP was performed randomly in the upper half arcade of each patient. The color was measured at baseline and at 1 week, 1 month, and 1 year using the spectrophotometer Vita Easyshade, Vita Bleached, and Vita classical Shade guide organized by value...
July 16, 2017: Journal of Esthetic and Restorative Dentistry
https://www.readbyqxmd.com/read/28629072/photodynamic-effect-of-light-harvesting-long-lived-triplet-excited-state-ruthenium-ii-polyimine-coumarin-complexes-dna-binding-photocleavage-and-anticancer-studies
#11
Raju Nomula, Xueyan Wu, Jianzhang Zhao, Nagegownivari R Munirathnam
Two coumarin based Ru(II)-polyimine complexes (Ru-1 and Ru-2) showing intense absorption of visible light and long-lived triplet excited states (~12-15μs) were used for study of the interaction with DNA. The binding of the complexes with CT-DNA were studied by UV-vis, fluorescence and time-resolved nanosecond transient absorption (ns-TA) spectroscopy. The results suggesting that the complexes interact with CT-DNA by intercalation mode of binding, showing the binding constants (Kb) 6.47×10(4) for Ru-1 and 5...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28488783/light-adaptation-and-the-evolution-of-vertebrate-photoreceptors
#12
Ala Morshedian, Gordon L Fain
KEY POINTS: Lamprey are cyclostomes, a group of vertebrates that diverged from lines leading to jawed vertebrates (including mammals) in the late Cambrian, 500 million years ago. It may therefore be possible to infer properties of photoreceptors in early vertebrate progenitors by comparing lamprey to other vertebrates. We show that lamprey rods and cones respond to light much like rods and cones in amphibians and mammals. They operate over a similar range of light intensities and adapt to backgrounds and bleaches nearly identically...
July 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28467262/comparison-of-effectiveness-and-sensitivity-using-two-in-office-bleaching-protocols-for-a-6-hydrogen-peroxide-gel-in-a-randomized-clinical-trial
#13
P Vildósola, F Vera, J Ramírez, J Rencoret, H Pretel, O B Oliveira, M Tonetto, J Martín, E Fernández
OBJECTIVE: The aim of this blinded and randomized clinical trial was to compare two application protocols (one 36-minute application vs three 12-minute applications). We then assessed the effectiveness of the bleaching and any increase in sensitivity that was induced by bleaching via a split-mouth design. METHODS AND MATERIALS: Thirty patients were treated. One group had a half arch of teeth treated with a traditional application protocol (group A: 3 × 12 minutes for two sessions)...
May 2017: Operative Dentistry
https://www.readbyqxmd.com/read/28463002/purely-visible-light-induced-photochromism-in-ag-tio2-nanoheterostructures
#14
D M Tobaldi, M J Hortigüela Gallo, G Otero-Irurueta, M K Singh, R C Pullar, M P Seabra, J A Labrincha
We report titania nanoheterostructures decorated with silver, exhibiting tuneable photochromic properties for the first time when stimulated only by visible white light (domestic indoor lamp), with no UV wavelengths. Photochromic materials show reversible color changes under light exposure. However, all inorganic photochromic nanoparticles (NPs) require UV light to operate. Conventionally, multicolor photochromism in Ag-TiO2 films involves a change in color to brownish-gray during UV-light irradiation (i.e...
May 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28451202/specific-protein-labeling-with-caged-fluorophores-for-dual-color-imaging-and-super-resolution-microscopy-in-living-cells
#15
Sebastian Hauke, Alexander von Appen, Tooba Quidwai, Jonas Ries, Richard Wombacher
We present new fluorophore-conjugates for dual-color photoactivation and super-resolution imaging inside live mammalian cells. These custom-designed, photo-caged Q-rhodamines and fluoresceins are cell-permeable, bright and localize specifically to intracellular targets. We utilized established orthogonal protein labeling strategies to precisely attach the photoactivatable fluorophores to proteins with subsequent activation of fluorescence by irradiation with UV light. That way, diffusive cytosolic proteins, histone proteins as well as filigree mitochondrial networks and focal adhesion proteins were visualized inside living cells...
January 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28402104/hydrogen-deuterium-exchange-mass-spectrometry-of-human-green-opsin-reveals-a-conserved-pro-pro-motif-in-extracellular-loop-2-of-monostable-visual-g-protein-coupled-receptors
#16
COMPARATIVE STUDY
Lukas Hofmann, Nathan S Alexander, Wenyu Sun, Jianye Zhang, Tivadar Orban, Krzysztof Palczewski
Opsins comprise the protein component of light sensitive G protein-coupled receptors (GPCRs) in the retina of the eye that are responsible for the transduction of light into a biochemical signal. Here, we used hydrogen/deuterium (H/D) exchange coupled with mass spectrometry to map conformational changes in green cone opsin upon light activation. We then compared these findings with those reported for rhodopsin. The extent of H/D exchange in green cone opsin was greater than in rhodopsin in the dark and bleached states, suggesting a higher structural heterogeneity for green cone opsin...
May 2, 2017: Biochemistry
https://www.readbyqxmd.com/read/28149462/effect-of-bleaching-agents-on-enamel-surface-of-bovine-teeth-a-sem-study
#17
Ana-Cristina Pimenta-Dutra, Rodrigo-de Castro Albuquerque, Luís-Fernando-Dos Santos-Alves Morgan, Geraldo-Magela Pereira, Eduardo Nunes, Martinho-Campolina-Rebello Horta, Frank-Ferreira Silveira
BACKGROUND: This study aimed to evaluate changes in the enamel surface of bovine teeth after whitening with exogenous bleaching agents: 10% carbamide peroxide (group 1), 16% carbamide peroxide (group 2) and 35% hydrogen peroxide activated by a light-emitting diode (LED) (group 3). The evaluations were performed by scanning electron microscopy (SEM). MATERIAL AND METHODS: Ninety bovine teeth were divided into five groups (n = 18). The bleaching agents 10% and 16% carbamide peroxide were applied for eight hours a day for 14 consecutive days...
January 2017: Journal of Clinical and Experimental Dentistry
https://www.readbyqxmd.com/read/27920339/identification-of-a-chlorophyll-dephytylase-involved-in-chlorophyll-turnover-in-arabidopsis
#18
Yao-Pin Lin, Meng-Chen Wu, Yee-Yung Charng
Chlorophyll turns over in green organs during photosystem repair and is salvaged via de- and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence...
December 2016: Plant Cell
https://www.readbyqxmd.com/read/27892835/effect-of-adhesive-restoration-and-bleaching-technique-on-the-concentration-of-hydrogen-peroxide-in-the-pulp-chamber
#19
V Cavalli, B G Silva, S B Berger, G Abuna, F C Marson, Cpm Tabchoury, M Giannini
This study aimed to quantify the concentration of hydrogen peroxide into the pulp chamber in the presence or absence of adhesive enamel restorations and to analyze the resin-dentin interface of bleached groups. Bovine incisors (120) were randomly divided into three groups according to enamel treatment (n=40 each): (1) enamel without restoration (control); (2) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a silorane-based (SB) system; or (3) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a dimethacrylate-based (DB) system...
March 2017: Operative Dentistry
https://www.readbyqxmd.com/read/27870065/photoacclimatory-and-photoprotective-responses-to-cold-versus-heat-stress-in-high-latitude-reef-corals
#20
Stefanie Pontasch, Paul L Fisher, Thomas Krueger, Sophie Dove, Ove Hoegh-Guldberg, William Leggat, Simon K Davy
Corals at the world's southernmost coral reef of Lord Howe Island (LHI) experience large temperature and light fluctuations and need to deal with periods of cold temperature (<18°C), but few studies have investigated how corals are able to cope with these conditions. Our study characterized the response of key photophysiological parameters, as well as photoacclimatory and photoprotective pigments (chlorophylls, xanthophylls, and β-carotene), to short-term (5-d) cold stress (~15°C; 7°C below control) in three LHI coral species hosting distinct Symbiodinium ITS2 types, and compared the coral-symbiont response to that under elevated temperature (~29°C; 7°C above control)...
April 2017: Journal of Phycology
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