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Light activated bleaching

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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
#1
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
#2
Ala Morshedian, Gordon L Fain
The earliest vertebrates were agnathans-fish-like organisms without jaws, which first appeared near the end of the Cambrian radiation. One group of agnathans became cyclostomes, which include lamprey and hagfish. Other agnathans gave rise to jawed vertebrates or gnathostomes, the group including all other existing vertebrate species. Because cyclostomes diverged from other vertebrates 500 million years ago, it may be possible to infer some of the properties of the retina of early vertebrate progenitors by comparing lamprey to other vertebrates...
May 9, 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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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)...
November 21, 2016: Journal of Phycology
https://www.readbyqxmd.com/read/27837096/down-regulation-of-the-alternative-sigma-factor-sigj-confers-a-photoprotective-phenotype-to-anabaena-pcc-7120
#11
Amit Srivastava, Klaus Brilisauer, Ashutosh K Rai, Anand Ballal, Karl Forchhammer, Anil K Tripathi
Alternative sigma factors belonging to Group 3 are thought to play an important role in the adaptation of cyanobacteria to environmental challenges by altering expression of genes needed for coping with such stresses. In this study, the role of an alternative sigma factor, SigJ, was analyzed in the filamentous nitrogen-fixing cyanobacterium, Anabaena sp. PCC 7120 by knocking down the expression of the sigJ gene (alr0277) employing an antisense RNA-mediated approach. In the absence of any stress, the knock-down (KD0277) or the wild-type strain both grew similarly...
November 10, 2016: Plant & Cell Physiology
https://www.readbyqxmd.com/read/27811449/bond-strength-of-resin-composite-to-light-activated-bleached-enamel
#12
T Yavuz, O Y Ozyilmaz, A N Ozturk, F Aykent
OBJECTIVES: This study evaluated the microtensile bond strength (μTBS) of a resin composite bonded to bleached enamel as a function of bleaching conditions. MATERIALS AND METHODS: The whiteness hydrogen peroxide (HP) bleaching agent containing 35% HP was applied to the central incisors' facial enamel surface and irradiated as follows: No treatment (G1; control); no light (G2); light-emitting diode, the 40s (G3); diode laser, the 20s (G4); and neodymium:yttrium aluminum garnet laser, 20s (G5)...
November 2016: Nigerian Journal of Clinical Practice
https://www.readbyqxmd.com/read/27747220/resin-bonding-of-self-etch-adhesives-to-bovine-dentin-bleached-from-pulp-chamber
#13
Akiko Haruyama, Atsushi Kameyama, Junji Kato, Shinji Takemoto, Yutaka Oda, Eiji Kawada, Toshiyuki Takahashi, Masahiro Furusawa
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...
2016: BioMed Research International
https://www.readbyqxmd.com/read/27701496/post-bleaching-sensitivity-in-patients-with-sickle-cell-disease
#14
Guacyra M Lisboa, Verónica L Guedes, Maria do R Ml Luna, Américo M Carneiro-Jr, Roberto C Stegun
Sickle cell disease (SCD) is a monogenic disease that affects millions of people worldwide. This study analyzed the effectiveness of bleaching and tooth sensitivity after in-office bleaching in patients with SCD. Forty volunteers were randomly assigned to four groups of 10 patients each (five with the SCD and five healthy controls) and treated using in-office bleaching with 35% hydrogen peroxide and different light activation protocols. No statistically significant difference was observed with relation to presence of tooth sensitivity, with or without use of a source of light for peroxide activation, and all bleaching therapies were effective, regardless of the technique employed and the presence/absence of sickle cell disease...
April 2016: Acta Odontológica Latinoamericana: AOL
https://www.readbyqxmd.com/read/27630493/impact-of-hydrogen-peroxide-activated-by-lighting-emitting-diode-laser-system-on-enamel-color-and-microhardness-an-in-situ-design
#15
Ana Bárbara Araújo Loiola, Aline Evangelista Souza-Gabriel, Renata Siqueira Scatolin, Silmara Aparecida Milori Corona
BACKGROUND: Hydrogen peroxide (HP) at lower concentration can provide less alteration on enamel surface and when combined with laser therapy, could decrease tooth sensitivity. This in situ study evaluated the influence of 15% and 35% HP gel activated by lighting-emitting diode (LED)/laser light for in-office tooth bleaching. MATERIALS AND METHODS: Forty-four bovine enamel slabs were polished and subjected to surface microhardness (load of 25 g for 5 s). The specimens were placed in intraoral palatal devices of 11 volunteers (n = 11)...
July 2016: Contemporary Clinical Dentistry
https://www.readbyqxmd.com/read/27575620/advanced-cellulose-fibers-for-efficient-immobilization-of-enzymes
#16
Iris Beatriz Vega Erramuspe, Elnaz Fazeli, Tuomas Näreoja, Jani Trygg, Pekka Hänninen, Thomas Heinze, Pedro Fardim
Biocatalytic pulp fibers were prepared using surface functionalization of bleached kraft pulp with amino groups (F) and further immobilization of a cross-linked glucose oxidase (G*) from Aspergillus niger. The cross-linked enzymes (G*) were characterized using X-ray spectroscopy, Fourier transform infrared spectroscopy, dynamic scanning calorimetry, and dynamic light scattering. According to standard assays, the G* content on the resulting fibers (FG*) was of 11 mg/g of fiber, and enzyme activity was of 215 U/g...
October 10, 2016: Biomacromolecules
https://www.readbyqxmd.com/read/27525071/comparative-clinical-and-psychosocial-benefits-of-tooth-bleaching-different-light-activation-of-a-38-peroxide-gel-in-a-preliminary-case-control-study
#17
Angelo Calderini, Simona Sciara, Chiara Semeria, Giuseppe Pantaleo, Elisabetta Polizzi
Tooth bleaching is a widespread dental treatment with important psychosocial antecedents and outcomes involved. In the activation of in-office bleaching agents, a selective light radiation, that is, a diode laser seems to be a positive choice to decrease the time of bleaching without surface modification and with no residual tooth sensitivity for maximum effect and minimal clinical and psychological side effects.
August 2016: Clinical Case Reports
https://www.readbyqxmd.com/read/27517329/stimulated-emission-depletion-nanoscopy-reveals-time-course-of-human-immunodeficiency-virus-proteolytic-maturation
#18
Janina Hanne, Fabian Göttfert, Jiří Schimer, Maria Anders-Össwein, Jan Konvalinka, Johann Engelhardt, Barbara Müller, Stefan W Hell, Hans-Georg Kräusslich
Concomitant with human immunodeficiency virus type 1 (HIV-1) budding from a host cell, cleavage of the structural Gag polyproteins by the viral protease (PR) triggers complete remodeling of virion architecture. This maturation process is essential for virus infectivity. Electron tomography provided structures of immature and mature HIV-1 with a diameter of 120-140 nm, but information about the sequence and dynamics of structural rearrangements is lacking. Here, we employed super-resolution STED (stimulated emission depletion) fluorescence nanoscopy of HIV-1 carrying labeled Gag to visualize the virion architecture...
September 27, 2016: ACS Nano
https://www.readbyqxmd.com/read/27433554/hydrogen-peroxide-diffusion-with-and-without-light-activation
#19
Carmen Llena, Leopoldo Forner, María Vazquez
OBJECTIVE: The aim of this study was to assess the dental bleaching efficacy of 37.5% hydrogen peroxide (HP), with and without light activation, in HP-exposed and unexposed areas. METHOD: 28 bovine teeth were selected and divided into two groups (n = 14). Crowns were detached and stained with tea. The gingival half was covered with a gingival barrier. In the incisal half, 37.5% HP (Pola Office+, SDI) was applied three times, with a 1-week interval between applications...
December 0: International Journal of Esthetic Dentistry
https://www.readbyqxmd.com/read/27358455/effect-of-rhodopsin-phosphorylation-on-dark-adaptation-in-mouse-rods
#20
Justin Berry, Rikard Frederiksen, Yun Yao, Soile Nymark, Jeannie Chen, Carter Cornwall
UNLABELLED: Rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that is activated when its 11-cis-retinal moiety is photoisomerized to all-trans retinal. This step initiates a cascade of reactions by which rods signal changes in light intensity. Like other GPCRs, rhodopsin is deactivated through receptor phosphorylation and arrestin binding. Full recovery of receptor sensitivity is then achieved when rhodopsin is regenerated through a series of steps that return the receptor to its ground state...
June 29, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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