Multidimensional reaction coordinate for the excited-state H-atom transfer in perylene quinones: importance of the 7-membered ring in hypocrellins A and B.

abstract：:There are controversial reports in the literature concerning the reactivity of singlet oxygen ((1)O(2)) with the redox probe 2',7'-dichlorodihydrofluorescein (DCFH). By carefully preparing solutions in which (1)O(2) is quantitatively generated in the presence of DCFH, we were able to show that the formation rate of th...

journal_title：Photochemistry and photobiology

authors： Daghastanli NA,Itri R,Baptista MS

更新日期：2008-09-01 00:00:00

abstract：:Plants protect themselves against excessive light by the induction of Delta pH-dependent nonphotochemical quenching (qE) that is associated with de-epoxidation of violaxanthin (V) to zeaxanthin (Z) in thylakoid membranes. In this work, we report that low light (12 micromol photons m(-2) s(-1)) is sufficient for a mark...

journal_title：Photochemistry and photobiology

authors： Ilík P,Kotabová E,Spundová M,Novák O,Kana R,Strzałka K

更新日期：2010-05-01 00:00:00

abstract：:Absolute fluorescence quantum yields are reported for the rhodamine 6G cation and the fluorescein dianion dyes in nine solvents. This information is combined with previously reported fluorescence lifetimes to deduce radiative and nonradiative decay rates. Along the alcohol series from methanol to octanol, rhodamine 6G...

journal_title：Photochemistry and photobiology

authors： Magde D,Wong R,Seybold PG

更新日期：2002-04-01 00:00:00

abstract：:Exposure of solutions containing both tryptophan and hydrogen peroxide to a pulsed ( approximately 180 fs) laser beam at 750 nm induces luminescence characteristic of 5-hydroxytryptophan. The results indicate that 3-photon excitation of tryptophan results in photoionization within the focal volume of the laser beam. T...

journal_title：Photochemistry and photobiology

authors： Bisby RH,Crisostomo AG,Botchway SW,Parker AW

更新日期：2009-01-01 00:00:00

abstract：:Photodynamic therapy (PDT) is an established therapeutic modality that uses nonionizing near-infrared light to activate photocytotoxicity of endogenous or exogenous photosensitizers (PSs). An ongoing avenue of cancer research involves leveraging PDT to stimulate antitumor immune responses; however, these effects appea...

journal_title：Photochemistry and photobiology

authors： Kercher EM,Nath S,Rizvi I,Spring BQ

更新日期：2020-03-01 00:00:00

abstract：:Photosensitized protein cross-linking has been recently developed to seal wounds and strengthen tissue. Although the photosensitizing dye, Rose Bengal (RB), is phototoxic to cultured cells, cytotoxicity does not accompany RB-photosensitized tissue repair in vivo. We investigated whether the environment surrounding cel...

journal_title：Photochemistry and photobiology

authors： Yao M,Gu C,Doyle FJ Jr,Zhu H,Redmond RW,Kochevar IE

更新日期：2014-03-01 00:00:00

abstract：:Leaf discs, enclosed in a photoacoustic (PA) chamber, generate two types of PA gas-uptake signals under certain conditions. Type I is manifested by a severe signal decrease that develops slowly under very low-light intensity and often reaches negative values. It is partially reversed by low-intensity far-red light. Ty...

journal_title：Photochemistry and photobiology

authors： Malkin S,Havaux M

更新日期：2001-10-01 00:00:00

abstract：:The kinetics of transients formed under photoexcitation of benzophenone (B) dissolved in three different polymers was studied by ns laser flash photolysis. These polymers were the soft rubbers poly (ethylene-co-butylene) (EB), polystyrene block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and hard polystyrene ...

journal_title：Photochemistry and photobiology

authors： Levin PP,Efremkin AF,Sultimova NB,Kasparov VV,Khudyakov IV

更新日期：2014-03-01 00:00:00

abstract：:Cationic polythiophenes have been shown to be potent antimicrobial compounds due to their ability to absorb visible light and sensitize the production of reactive oxygen species (ROS) as well as their ability to selectively associate with and damage negatively charged cell envelopes. This study demonstrates the abilit...

journal_title：Photochemistry and photobiology

authors： Brown DM,Yang J,Strach EW,Khalil MI,Whitten DG

更新日期：2018-11-01 00:00:00

abstract：:The UVA and UVB components of sunlight can produce three classes of bipyrimidine DNA photolesions [cyclobutane pyrimidine dimers (CPDs), pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) and related Dewar valence isomers (DewarPPs)]. The UVA/UVB ratio of sunlight is high in winter and low in summer in the Northern He...

journal_title：Photochemistry and photobiology

authors： Nishimura K,Ikehata H,Douki T,Cadet J,Sugiura S,Mori T

更新日期：2020-12-03 00:00:00

abstract：:People can get oral cancers from UV (290-400 nm) exposures. Besides high outdoor UV exposures, high indoor UV exposures to oral tissues can occur when consumers use UV-emitting tanning devices to either tan or whiten their teeth. We compared the carcinogenic risks of skin to oral tissue cells after UVB (290-320 nm) ex...

journal_title：Photochemistry and photobiology

authors： Breger J,Baeva L,Agrawal A,Shindell E,Godar DE

更新日期：2013-05-01 00:00:00

abstract：:The fluorescent pH probe carboxy-seminaphtorhodafluor-1 (C-Snarf-1) has been used for laser microspectro-fluorometric assays of intracellular pH in 3T3 mouse fibroblasts treated with hypocrellin A. These results are compared to those previously obtained with the structurally related hydroxylated polycyclic quinone, hy...

journal_title：Photochemistry and photobiology

authors： Chaloupka R,Sureau F,Kocisova E,Petrich JW

更新日期：1998-07-01 00:00:00

abstract：:Because metallothionein (MT) is elevated and may be protective in UV-irradiated skin, we have studied the effects of UV and other agents on MT transcription using the sheep MT 1A promoter, linked to the beta-galactosidase gene and stably transfected into human cell lines. beta-galactosidase reporter activity was induc...

journal_title：Photochemistry and photobiology

authors： Hansen C,Ablett E,Green A,Sturm RA,Dunn IS,Fairlie DP,West ML,Parsons PG

更新日期：1997-03-01 00:00:00

abstract：:Pyrimidine dimers were measured in epidermal DNA of SKH:HR1 mice following exposure to solar-simulated UV radiation (SSUV, 290-400 nm) or to UVA (320-400 nm). Mice were exposed to SSUV or UVA after topical application (2 mg/cm2) of vehicle, a UVB absorber (5% 2-ethylhexyl p-methoxycinnamate [2-EHMC]), or a broad-spect...

journal_title：Photochemistry and photobiology

authors： Ley RD,Fourtanier A

更新日期：1997-06-01 00:00:00

abstract：:Gel sequencing experiments with the 5'- and 3'-end-labeled oligonucleotides d(A3GA4GA5GA6GA3G) and d(AT)10 have demonstrated that dimeric adenine photoproducts and thymine-adenine photoadducts constitute alkali-labile lesions in UV-irradiated DNA. On treatment with hot piperidine, DNA strand breakage occurs predominan...

journal_title：Photochemistry and photobiology

authors： Hejmadi V,Stevenson C,Kumar S,Davies RJ

更新日期：1994-02-01 00:00:00

abstract：:Dark-grown leaves of maize (Zea mays), wheat (Triticum aestivum), wild-type pea (Pisum sativum) and its light-independent photomorphogenesis mutant (lip1) have different proportions of protochlorophyllide (Pchlide) forms as revealed by low-temperature fluorescence emission spectra. Four discrete spectral forms of Pchl...

journal_title：Photochemistry and photobiology

authors： Myśliwa-Kurdziel B,Amirjani MR,Strzałka K,Sundqvist C

更新日期：2003-08-01 00:00:00

abstract：:Photoproducts in double-stranded DNA induced by 193 nm radiation have been investigated. Double-stranded, supercoiled pBR322 DNA in buffered aqueous solution was exposed to varying fluences of 193 nm radiation from an ArF excimer laser. The quantum yields for formation of cyclobutylpyrimidine dimers, frank strand brea...

journal_title：Photochemistry and photobiology

authors： Kochevar IE,Buckley LA

更新日期：1990-05-01 00:00:00

abstract：:The synthesis, characterization and photophysical properties of two perfluoroalkyl (5,10,15,20-tetrakis-[trifluoromethyl]- and [heptafluoropropyl]-porphyrin) and two perfluoroaryl (5,10,15,20-tetrakis-[2,6-difluorophenyl]- and [pentafluorophenyl]-porphyrin) are described, with reference to their potential in both phot...

journal_title：Photochemistry and photobiology

authors： Grancho JC,Pereira MM,Miguel Mda G,Rocha GA,Burrows HD

更新日期：2002-03-01 00:00:00

abstract：:High-altitude Andean lakes (HAAL) are a treasure chest for microbiological research in South America. Their indigenous microbial communities are exposed to extremely high UV irradiation and to multiple chemical extremes (Arsenic, high salt content, alkalinity). Microbes are found both, free-living or associated into m...

journal_title：Photochemistry and photobiology

authors： Albarracín VH,Gärtner W,Farias ME

更新日期：2016-01-01 00:00:00

abstract：:Our recent study follows up an earlier one which demonstrated hypericin-mediated photocytotoxic effects on HT-29 adenocarcinoma cells by light fractionation with a longer dark pause between two unequal light doses (Sackova, A. [2005] Photochem. Photobiol.81, 1411-1416). Here, we present closer study on events invoked ...

journal_title：Photochemistry and photobiology

authors： Kuliková L,Mikeš J,Hýžďalová M,Palumbo G,Fedoročko P

更新日期：2010-11-01 00:00:00

abstract：:Photodimerization of cocrystals of four bispyridylethylenes and two stilbazoles with urea as a template in the solid state has been investigated following our success with thiourea. Four investigated olefins photodimerized quantitatively to a single dimer in the crystalline state only. The reactivity of urea-olefin cr...

journal_title：Photochemistry and photobiology

authors： Bhogala BR,Captain B,Ramamurthy V

更新日期：2015-05-01 00:00:00

abstract：:Bacteriochlorophyll (BChl) e was coassembled with BChl c in Triton X-100 micelles in aqueous solutions. The Qy absorption bands of the coaggregates were positioned between those of aggregates consisting solely of BChl c or e. The electronic absorption spectra of the coaggregates could not be reproduced by linear combi...

journal_title：Photochemistry and photobiology

authors： Saga Y,Saiki T,Takahashi N,Shibata Y,Tamiaki H

更新日期：2014-05-01 00:00:00

abstract：:Persister bacteria tolerate bactericidal antibiotics due to transient and reversible phenotypic changes. As these bacteria can limit the effectiveness of antibiotics to eradicate certain infections, their elimination is a relevant issue. Photodynamic therapy seems suitable for this purpose, but phenotypic tolerance to...

journal_title：Photochemistry and photobiology

authors： Oppezzo OJ,Forte Giacobone AF

更新日期：2018-01-01 00:00:00

abstract：:Excessive exposure of solar ultraviolet (UV) radiation, particularly its UV-B component, to humans causes many adverse effects that include erythema, hyperplasia, hyperpigmentation, immunosuppression, photoaging and skin cancer. In recent years, there is increasing use of botanical agents in skin care products. Pomegr...

journal_title：Photochemistry and photobiology

authors： Afaq F,Malik A,Syed D,Maes D,Matsui MS,Mukhtar H

更新日期：2005-01-01 00:00:00

abstract：:The UV radiation environment on planetary surfaces and within atmospheres is of importance in a wide range of scientific disciplines. Solar UV radiation is a driving force of chemical and organic evolution and serves also as a constraint in biological evolution. In this work we modeled the transmission of present and ...

journal_title：Photochemistry and photobiology

authors： Rontó G,Bérces A,Lammer H,Cockell CS,Molina-Cuberos GJ,Patel MR,Selsis F

更新日期：2003-01-01 00:00:00

abstract：:Detergent solubilized bacteriorhodopsin (BR) proteins which contain alterations made by site-directed mutagenesis (Asp-96----Asn, D96N; Asp-85----Asn, D85N; and Arg-82----Gln, R82Q) have been studied with resonance Raman spectroscopy. Raman spectra of the light-adapted (BRLA) and M species in D96N are identical to tho...

journal_title：Photochemistry and photobiology

authors： Lin SW,Fodor SP,Miercke LJ,Shand RF,Betlach MC,Stroud RM,Mathies RA

更新日期：1991-03-01 00:00:00

abstract：:Self-aggregation of naturally occurring bacteriochlorophyll (BChl)-e in nonpolar organic solvents was investigated by visible absorption, fluorescence emission and circular dichroism spectra. Cultured brown-colored photosynthetic bacteria have several BChl-e as light-harvesting antenna pigments. Three major BChl-e hom...

journal_title：Photochemistry and photobiology

authors： Saga Y,Matsuura K,Tamiaki H

更新日期：2001-07-01 00:00:00

abstract：:Vitamin A palmitate has been used in cosmetics; however, studies report that this substance shows photoreactivity that can lead to loss of safety and efficacy. On the other hand, photostabilizers have been used to increase sunscreen photostability and consequently their safety and effectiveness. Thus, this study aimed...

journal_title：Photochemistry and photobiology

authors： Benevenuto CG,Di Matteo MA,Maia Campos PM,Gaspar LR

更新日期：2010-11-01 00:00:00

abstract：:Organisms living in coastal waters are exposed to anthropogenic contaminants from terrestrial drainage, ice melting and maritime traffic and to enhanced UVB radiation (UVBR; 280-320 nm) caused by decreased concentrations of ozone in the stratosphere. This article reviews available information about the combined effect...

journal_title：Photochemistry and photobiology

authors： Pelletier E,Sargian P,Payet J,Demers S

更新日期：2006-07-01 00:00:00

abstract：:Previous studies with methylene blue (MB) in red cell suspensions have demonstrated that extracellular, but not intracellular, virus can be readily photoinactivated. To test if the resistance of intracellular virus to inactivation is related to the permanent positive charge of the phenothiazine, a series of uncharged ...

journal_title：Photochemistry and photobiology

authors： Skripchenko A,Robinette D,Wagner SJ

更新日期：1997-03-01 00:00:00