The Experts below are selected from a list of 339 Experts worldwide ranked by ideXlab platform
Michael R Hamblin - One of the best experts on this subject based on the ideXlab platform.
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low level laser therapy for zymosan induced arthritis in rats importance of Illumination Time
Lasers in Surgery and Medicine, 2007Co-Authors: Ana P Castano, Tianhong Dai, Ilya V Yaroslavsky, Richard Cohen, William Apruzzese, Michael Smotrich, Michael R HamblinAbstract:Background It has been proposed for many years that low-level laser (or light) therapy (LLLT) can ameliorate the pain, swelling, and inflammation associated with various forms of arthritis. Light is thought to be absorbed by mitochondrial chromophores leading to an increase in adenosine triphosphate (ATP), reactive oxygen species and/or cyclic AMP production and consequent gene transcription via activation of transcription factors. However, despite many reports about the positive effects of LLLT in arthritis and in medicine in general, its use remains controversial. For all indications (including arthritis) the optimum optical parameters have been difficult to establish and so far are unknown.
Michel Orrit - One of the best experts on this subject based on the ideXlab platform.
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photobleaching of rhodamine 6g in poly vinyl alcohol at the ensemble and single molecule levels
Journal of Physical Chemistry A, 2004Co-Authors: Rob Zondervan, Florian Kulzer, And Mikhail A Kolchenko, Michel OrritAbstract:Photobleaching is a severely limiting factor in the optical study of single biomolecules. We investigate the photobleaching of rhodamine 6G (R6G) ensembles in poly(vinyl alcohol) (PVA) as a function of Illumination Time, excitation intensity, the presence of oxygen, and temperature. We observe nonexponential kinetics related to primary photobleaching through two dark statesthe triplet state and a radical anionand to secondary photobleaching after the optical excitation of those dark states. Reactions of the metastable states with oxygen can lead either to photoproducts or to a recovery of the ground state. Oxygen can therefore enhance or reduce photobleaching, depending on the experimental conditions. At low temperature, photobleaching is reduced although not completely suppressed. Despite the presence of the long-lived radical anion, we are able to observe single R6G molecules in PVA. At room temperature, only relatively bleaching-resistant molecules are resolved as individuals. At low temperature, the o...
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photoblinking of rhodamine 6g in poly vinyl alcohol radical dark state formed through the triplet
Journal of Physical Chemistry A, 2003Co-Authors: Rob Zondervan, Florian Kulzer, S B Orlinskii, Michel OrritAbstract:We investigate the fluorescence intensity of rhodamine 6G in poly(vinyl alcohol) as a function of excitation intensity, Illumination Time, the presence of oxygen, and temperature. The variations in emissivity (or fluorescence brightness) are attributed to a dark state, which shows populating kinetics resembling those of the triplet state, but a much longer lifeTime. We simulate the observed kinetics by a four-level model, in which a long-lived dark state is formed through the triplet as an intermediate state. The weak temperature dependence of the lifeTime of the dark state points to electron tunneling as the main recovery process. This intermolecular mechanism also explains the observed broad distribution of lifeTimes. An electron-spin-resonance experiment confirms the assignment of the dark state to a radical. For the first Time, photoinduced charge transfer is identified as a source of blinking in single-molecule measurements.
Ana P Castano - One of the best experts on this subject based on the ideXlab platform.
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low level laser therapy for zymosan induced arthritis in rats importance of Illumination Time
Lasers in Surgery and Medicine, 2007Co-Authors: Ana P Castano, Tianhong Dai, Ilya V Yaroslavsky, Richard Cohen, William Apruzzese, Michael Smotrich, Michael R HamblinAbstract:Background It has been proposed for many years that low-level laser (or light) therapy (LLLT) can ameliorate the pain, swelling, and inflammation associated with various forms of arthritis. Light is thought to be absorbed by mitochondrial chromophores leading to an increase in adenosine triphosphate (ATP), reactive oxygen species and/or cyclic AMP production and consequent gene transcription via activation of transcription factors. However, despite many reports about the positive effects of LLLT in arthritis and in medicine in general, its use remains controversial. For all indications (including arthritis) the optimum optical parameters have been difficult to establish and so far are unknown.
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low level light therapy for zymosan induced arthritis in rats
Proceedings of SPIE, 2007Co-Authors: Ana P Castano, Tianhong Dai, Ilya V Yaroslavsky, Richard Cohen, William Apruzzese, Tatiana N Demidovarice, Elena Salomatina, Anna N Yaroslavsky, Michael SmotrichAbstract:It has been known for many years that low level laser (or light) therapy (LLLT) can ameliorate the pain, swelling and inflammation associated with various forms of arthritis. Light is absorbed by mitochondrial chromophores leading to an increase in ATP, reactive oxygen species and/or cyclic AMP production and consequent gene transcription via activation of transcription factors. However, despite many reports about the positive effects of LLLT in medicine, its use remains controversial. Our laboratory has developed animal models designed to objectively quantify response to LLLT and compare different light delivery regimens. In the arthritis model we inject zymosan into rat knee joints to induce inflammatory arthritis. We have compared Illumination regimens consisting of a high and low fluence (3 J/cm 2 and 30 J/cm 2 ), delivered at a high and low irradiance (5 mW/cm2 and 50 mW/cm 2 ) using 810-nm laser light daily for 5 days, with the effect of conventional corticosteroid (dexamethasone) therapy. Results indicated that Illumination with 810-nm laser is highly effective (almost as good as dexamethasone) at reducing swelling and that longer Illumination Time was more important in determining effectiveness than either total fluence delivered or irradiance. Experiments carried out using 810-nm LLLT on excisional wound healing in mice also confirmed the importance of longer Illumination Times. These data will be of value in designing clinical trials of LLLT.
Godlisten N Shao - One of the best experts on this subject based on the ideXlab platform.
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sol gel synthesis of sodium silicate and titanium oxychloride based tio2 sio2 aerogels and their photocatalytic property under uv irradiation
Chemical Engineering Journal, 2013Co-Authors: Godlisten N Shao, Sung Jeong Jeon, S M Imran, Pradip B SarawadeAbstract:Abstract Binary titania–silica metal oxides (TiO2–SiO2) have preferentially been used as photocatalysts for the degradation of organic contaminants under UV irradiation. Herein we synthesized TiO2–SiO2 aerogel powders with different Si-to-Ti ratios suitable for decolorization of organic pollutants using less expensive silica source (sodium silicate) and titanium oxychloride as a titania precursor. Consequently, the surfaces of the alcogels were hydrophobized using trimethylchlorosilane (TMCS) as a silylating agent to yield hydrophobic aerogel powders at ambient pressure drying. The as-prepared samples were calcined at different temperatures ranging from 200 to 1000 °C to evaluate the effect of the heat treatment in the microstructure of the aerogels. The physico-chemical properties of the aerogels were examined by XRD, FTIR, XRF, TEM, SEM, N2 gas physisorption studies, TGA/DTA and diffusive reflectance spectrometry analyses. It was found that calcination temperature is an important factor in improving the porosity and crystallinity of the aerogels however; it has a detrimental effect on the hydrophobicity and photochemical performance of the aerogels. The as-synthesized aerogels were hydrophobic and exhibited the highest activity toward decolorization of methylene blue. The hydrophilic aerogels were obtained after calcination at temperature ⩾500 °C however; the formed samples possessed lower activities. Hydroxyl radicals ( OH) detection experiment performed in the presence of the photocatalysts indicated that the generation of radicals during irradiation increases with increasing Illumination Time.
Simón Navarro - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic oxidation of six pesticides listed as endocrine disruptor chemicals from wastewater using two different tio2 samples at pilot plant scale under sunlight irradiation
Journal of Photochemistry and Photobiology A-chemistry, 2018Co-Authors: Nuria Vela, José Fenoll, May Calin, Maria J Yanezgascon, Isabel Garrido, Gabriel Perezlucas, Simón NavarroAbstract:Abstract The photocatalyzed degradation of a mixture of six pesticides (malathion, fenotrothion, quinalphos, vinclozoline, dimethoate and fenarimol) with endocrine disrupting activity has been studied in sewage wastewater effluent under natural sunlight at pilot plant scale. The initial level of each pesticide was 0.30 mg L−1. For this, two commercial TiO2 nanopowders (Degussa P25 and Kronos vlp 7000) were used as photocatalysts. The operational conditions (catalyst loading, effect of electron acceptor and pH) were previously optimized under laboratory conditions using a photoreactor. The results show that the use of TiO2 alongside an electron acceptor like Na2S2O8 strongly enhances the degradation rate of the studied pesticides compared with photolytic tests, especially Degussa P25. The photodegradation process followed pseudo-first order kinetics in all cases. In our experimental conditions, the necessary Time necessary for 90% degradation (DT90) varied from 79 to 1270 min (6–108 min as normalized Illumination Time, t30W) for malathion and fenarimol, respectively for TiO2 vlp 7000 and 32–817 min (t30W = 3–69 min) for the same pesticides, in the case of TiO2 P25. The results confirm the efficacy of the treatment to remove recalcitrant pollutants from wastewater using natural sunlight as renewable source.
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Heterogeneous photocatalytic oxidation of cyprodinil and fludioxonil in leaching water under solar irradiation.
Chemosphere, 2011Co-Authors: José Fenoll, Encarnación Ruiz, Pilar Hellín, Pilar Flores, Simón NavarroAbstract:Abstract The efficiency of ZnO and TiO 2 suspensions in the photocatalytic degradation of two fungicides (cyprodinil and fludioxonil) in leaching water was investigated. The experiments were carried out at pilot plant scale using compound parabolic collectors under natural sunlight. The blank experiments for both irradiated compounds solutions showed that both oxides strongly enhanced the removal of the fungicides. The addition of an oxidant (Na 2 S 2 O 8 ) to the ZnO or TiO 2 increased the rate of photooxidation. The degradation of cyprodinil and fludioxonil followed first order kinetics according to the Langmuir–Hinshelwood model. Complete degradation of both fungicides was achieved within 4 h ( t 30W = 18 min) when treated with illuminated ZnO. The disappearance Time (DT 75 ), when referred to the normalized Illumination Time ( t 30W ), was lower than 40 and 550 min ( t 30W = 2 and 40 min) for both fungicides using ZnO or TiO 2 , respectively. ZnO appeared to be more effective in cyprodinil and fludioxonil oxidation than TiO 2 probably due to its nonstoichiometry.
