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Light activated bleaching

Rajeev Yadav, H Peter Lu
The N-methyl-d-aspartate (NMDA) receptor ion-channel is activated by the binding of ligands, along with the application of action potential, important for synaptic transmission and memory functions. Despite substantial knowledge of the structure and function, the gating mechanism of the NMDA receptor ion channel for electric on-off signals is still a topic of debate. We investigate the NMDA receptor partition distribution and the associated channel's open-close electric signal trajectories using a combined approach of correlating single-molecule fluorescence photo-bleaching, single-molecule super-resolution imaging, and single-channel electric patch-clamp recording...
March 8, 2018: Physical Chemistry Chemical Physics: PCCP
Philip D Kiser, Jianye Zhang, Aditya Sharma, Juan M Angueyra, Alexander V Kolesnikov, Mohsen Badiee, Gregory P Tochtrop, Junzo Kinoshita, Neal S Peachey, Wei Li, Vladimir J Kefalov, Krzysztof Palczewski
Visual function in vertebrates critically depends on the continuous regeneration of visual pigments in rod and cone photoreceptors. RPE65 is a well-established retinoid isomerase in the pigment epithelium that regenerates rhodopsin during the rod visual cycle; however, its contribution to the regeneration of cone pigments remains obscure. In this study, we use potent and selective RPE65 inhibitors in rod- and cone-dominant animal models to discern the role of this enzyme in cone-mediated vision. We confirm that retinylamine and emixustat-family compounds selectively inhibit RPE65 over DES1, the putative retinoid isomerase of the intraretinal visual cycle...
March 2, 2018: Journal of General Physiology
Zahra Derakhshan, Margherita Ferrante, Marzieh Tadi, Farnoosh Ansari, Ali Heydari, Motahreh Sadat Hosseini, Gea Oliveri Conti, Elham Khalili Sadarabad
Pomegranate (Punica granatum L.) is extensively cultivated in Middle East especially in Iran. For centuries, this fruit has been used in Iranian herbal medicine. Pomegranate peel, seed and juice contain considerable amounts of phenolic compounds and have antioxidant activity. Pomegranate peels, juice and seeds from three regions of Natanz, Shahreza, and Doorak were obtained. Antioxidant activity, total phenolic, flavonoids, and flavonols contents of pomegranate peels, seeds and juices extracts were analyzed...
February 12, 2018: Food and Chemical Toxicology
Lin Song, Tianyi Wang, Volker Körstgens, Weijia Wang, Nitin Saxena, Christoph J Schaffer, Thomas Fröschl, Nicola Hüsing, Sigrid Bernstorff, Peter Müller-Buschbaum
Hierarchically structured titania films, exhibiting interconnected foam-like nanostructures and large scale channel-type superstructures, are achieved in an energy saving way at low temperatures by a polymer template-assisted sol-gel synthesis in combination with a wet imprinting process. The surface morphology is probed with scanning electron microscopy and atomic force microscopy, while the inner morphology is characterized with grazing incidence small-angle x-ray scattering measurements. Compared to the initial hybrid films, the titania films showed reduced structure sizes caused by the polymer template removal...
February 14, 2018: ChemSusChem
Harpreet Kaur, Pushap Raj, Hemant Sharma, Meenakshi Verma, Narinder Singh, Navneet Kaur
Carbon Quantum Dots (CDs) owing to its unique photophysical properties have attracted immense consideration of the researchers in last decade to explore its applications in the fields of bio-imaging and sensing. In the present work, we have developed a novel CDs functionalized with Calix[4]arene derivative by hydrothermal route to detect biologically pertinent Zn2+ ions. Surface modification of CDs enhances fluorescence efficiency apart from introducing active surface sites broadening its sensor capabilities...
June 7, 2018: Analytica Chimica Acta
Gen Li, Feng Wang, Peng Liu, Zheming Chen, Ping Lei, Zhongshan Xu, Zengxi Li, Yanfen Ding, Shimin Zhang, Mingshu Yang
As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO2 (PDs-TiO2) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO4)2...
January 18, 2018: Chemosphere
Sima Shahabi, Hadi Assadian, Alireza Mahmoudi Nahavandi, Hanieh Nokhbatolfoghahaei
Introduction: The demand for esthetic dental treatments is increasing in recent years mainly due to improved oral hygiene and better maintenance of oral health and teeth in older individuals. Bleaching of discolored anterior teeth is the most popular among esthetic dental treatments. Even individuals with sound teeth and adequate esthetics seek to have whiter teeth in the anterior region. The aim of this study was to evaluate tooth color changes following conventional in-office bleaching techniques compared to light-activated methods using different light sources...
2018: Journal of Lasers in Medical Sciences
Bianca Medeiros Maran, Adrieli Burey, Thalita de Paris Matos, Alessandro D Loguercio, Alessandra Reis
OBJECTIVE: 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? DATA AND SOURCE: 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, EMBASE, Cochrane Library, and SIGLE without restrictions in May 2016 and was updated in August 2017...
December 28, 2017: Journal of Dentistry
Rfl Mondelli, Fap Rizzante, E R Rosa, Afs Borges, A Y Furuse, Jfs Bombonatti
The present in vivo randomized, triple-blinded, and split-mouth clinical study evaluated the effectiveness of a hybrid light (HL) source on the color change, stability, and tooth sensitivity in patients submitted to different in-office bleaching techniques. Twenty volunteers were divided into two groups and four subgroups. A split-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): 35% Lase Peroxide Sensy (LPS) + HL: 35% hydrogen peroxide (HP) + HL; 35% LPS: 35% HP; 25% LPS + HL: 25% HP + HL; and 35% Whiteness HP (WHP): 35% HP...
January 2018: Operative Dentistry
Qiusheng Wu, Bingru Huang, Xingyun Peng, Sailing He, Qiuqiang Zhan
Optical super-resolution microscopy has become a powerful technique to help scientists to monitor the sample of interest at nanoscale. Fluorescence emission difference (FED) microscopy, a very facile super-resolution method, does not require high depleting laser intensity and is independent on the species of agents, which makes FED microscopy possess great potential. However, to date, the biomarkers applied in FED microscopy usually suffer from a photo-bleaching problem. In this work, by introducing Er3+ activated upconverting nanoparticles with red-color emission and non-photobleaching properties, we demonstrate nonbleaching super-resolution imaging with FED microscopy...
December 11, 2017: Optics Express
André L Faria-E-Silva, Christopher Fanger, Lillian Nguyen, Demetri Howerton, Carmem S Pfeifer
This study aimed to evaluate the effect of the composite shade and distance from the light-curing unit (LCU) tip on the irradiance reaching the bottom of composite disks and on the depth of polymerization. Composites of three shades (opaque - OXDC, bleach - BXL, and A2) were inserted into molds with 3-mm of thickness positioned over a spectrometer and photo-activated with the LCU (Bluephase) tip placed at 0 or 1 cm from the composite surface. The mean irradiance reaching the bottom of composite was recorded during the entire photo-activation (30 s)...
September 2017: Brazilian Dental Journal
Alexandra Tikidji-Hamburyan, Katja Reinhard, Riccardo Storchi, Johannes Dietter, Hartwig Seitter, Katherine E Davis, Saad Idrees, Marion Mutter, Lauren Walmsley, Robert A Bedford, Marius Ueffing, Petri Ala-Laurila, Timothy M Brown, Robert J Lucas, Thomas A Münch
Rod and cone photoreceptors support vision across large light intensity ranges. Rods, active under dim illumination, are thought to saturate at higher (photopic) irradiances. The extent of rod saturation is not well defined; some studies report rod activity well into the photopic range. Using electrophysiological recordings from retina and dorsal lateral geniculate nucleus of cone-deficient and visually intact mice, we describe stimulus and physiological factors that influence photopic rod-driven responses...
November 27, 2017: Nature Communications
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
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
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
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
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
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
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
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
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