Analysis of phosphorescence decay in heterogeneous systems: consequences of finite excitation flash duration.


:Analysis of phosphorescence lifetimes using the Stern-Volmer equation is a reliable means of determining quencher concentration for a uniform sample. Methods of analysis for heterogeneous systems are based on the assumption that the excitation is produced by a momentary flash. This condition is an idealization because a real flash has a finite duration and a complex time profile. In the case of a heterogeneous quencher concentration, an excitation flash produces different initial intensities and different times of peak intensity from compartments having different concentrations of quencher. We formulated a model to explore the effects of flash duration on the shape of the emission curve obtained from systems in which the heterogeneity is continuous. We developed mathematical models that can be used to recover fitting parameters of continuous distributions of reciprocal lifetimes approximated as rectangular or Gaussian distributions, or an arbitrary histogram. We also formulated a procedure to convert the distribution of reciprocal lifetimes into a volume distribution of quencher concentration. We found that (1) the Stern-Volmer ratio of phosphorescence intensities cannot be employed for interpretation of pulse phosphorometric data in terms of a volume distribution of quencher; (2) shortening the flash duration decreases the difference of initial intensities between compartments having high and low quencher concentration; (3) the parameters of the volume distribution of quencher concentration can be recovered correctly only after taking account of the difference in initial intensities; and (4) calibration of the initial intensities for a given fitting delay and flash function is necessary.


Photochem Photobiol


Golub AS,Popel AS,Zheng L,Pittman RN


Has Abstract


1999-06-01 00:00:00












  • A blue fluorescent protein from a yellow-emitting luminous bacterium.

    abstract::Vibrio fischeri strain Y1 emits yellow light in vivo due to the participation of a yellow fluorescent protein (YFP) in the luciferase reaction. In this study it was found that the organism also produces a protein (referred to as Y1-BFP) emitting strong blue fluorescence. Its molecular weight, about 25 kDa, is the same...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Karatani H,Wilson T,Hastings JW

    更新日期:1992-02-01 00:00:00

  • Low-level laser therapy ameliorates CCl4-induced liver cirrhosis in rats.

    abstract::This study investigated the effects of low-level laser therapy (LLLT) in the liver function, structure and inflammation in a experimental model of carbon tetrachloride (CCl(4))-induced liver cirrhosis. Wistar rats were divided into Control, LLLT, CCl(4) and CCl(4) +LLLT groups. CCl(4) groups received CCl(4) (0.4 g kg(...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Oliveira-Junior MC,Monteiro AS,Leal-Junior EC,Munin E,Osório RA,Ribeiro W,Vieira RP

    更新日期:2013-01-01 00:00:00

  • A far-red fluorescent contrast agent to image epidermal growth factor receptor expression.

    abstract::Recent developments in optical technologies have the potential to improve the speed and accuracy of screening and diagnosis of curable precancerous lesions and early cancer, thereby decreasing the costs of detection and management of epithelial malignancies. The development of molecular-specific contrast agents for ma...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Hsu ER,Anslyn EV,Dharmawardhane S,Alizadeh-Naderi R,Aaron JS,Sokolov KV,El-Naggar AK,Gillenwater AM,Richards-Kortum RR

    更新日期:2004-03-01 00:00:00

  • UV induced (6-4) photoproducts are distributed differently than cyclobutane dimers in nucleosomes.

    abstract::We have compared the distributions of two stable UV photoproducts in nucleosome core DNA at the single-nucleotide level using a T4 polymerase-exonuclease mapping procedure. The distribution of pyrimidine-pyrimidone (6-4) dimers was uncovered by reversing the major UV photo-product, cis-syn cyclobutane pyrimidine dimer...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Gale JM,Smerdon MJ

    更新日期:1990-04-01 00:00:00

  • Using computational fluid dynamics modeling to evaluate the design of hospital ultraviolet germicidal irradiation systems for inactivating airborne mycobacteria.

    abstract::This research was conducted to evaluate the design of hospital ultraviolet germicidal irradiation (UVGI) systems and to assess their effectiveness for inactivating airborne mycobacteria. A computational fluid dynamics (CFD) model was developed and tested by simulating previous experiments measuring the effectiveness o...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Xu P,Fisher N,Miller SL

    更新日期:2013-07-01 00:00:00

  • Skin cancer risks avoided by the Montreal Protocol--worldwide modeling integrating coupled climate-chemistry models with a risk model for UV.

    abstract::The assessment model for ultraviolet radiation and risk "AMOUR" is applied to output from two chemistry-climate models (CCMs). Results from the UK Chemistry and Aerosols CCM are used to quantify the worldwide skin cancer risk avoided by the Montreal Protocol and its amendments: by the year 2030, two million cases of s...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: van Dijk A,Slaper H,den Outer PN,Morgenstern O,Braesicke P,Pyle JA,Garny H,Stenke A,Dameris M,Kazantzidis A,Tourpali K,Bais AF

    更新日期:2013-01-01 00:00:00

  • Photogeneration and chemistry of biphenyl quinone methides from hydroxybiphenyl methanols.

    abstract::The photosolvolysis of several biphenyl methanols (Ph-PhCH[Ph]OH) substituted with hydroxy or methoxy groups on the benzene ring not containing the -CH(Ph)OH moiety has been studied in aqueous solution. This work is a continuation of our studies of photosolvolysis of hydroxy-substituted arylmethanols that generate qui...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Xu M,Lukeman M,Wan P

    更新日期:2006-01-01 00:00:00

  • Damage to DNA in bacterioplankton: a model of damage by ultraviolet radiation and its repair as influenced by vertical mixing.

    abstract::A model of UV-induced DNA damage in oceanic bacterioplankton was developed and tested against previously published and novel measurements of cyclobutane pyrimidine dimers (CPD) in surface layers of the ocean. The model describes the effects of solar irradiance, wind-forced mixing of bacterioplankton and optical proper...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Huot Y,Jeffrey WH,Davis RF,Cullen JJ

    更新日期:2000-07-01 00:00:00

  • Fluorescence polarization studies of B-phycoerythrin oriented in polymer film.

    abstract::Polarized steady-state fluorescence and fluorescence excitation spectra as well as time-resolved fluorescence for B-phycoerythrin (B-PE) from red algae, Porphyridium cruentum, embedded in polyvinyl stretched films were measured. The lifetimes of polarized fluorescence were analyzed using exponential components and fra...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Frackowiak D,Ptak A,Gryczynski Z,Gryczynski I,Targowski P,Zelent B

    更新日期:2004-01-01 00:00:00

  • Validation and application of a model of oxygen consumption and diffusion during photodynamic therapy in vitro.

    abstract::The photophysical parameters for the photosensitizer Pd(II) meso-Tetra(4-carboxyphenyl) porphine (PdT790) acquired in a previous study were incorporated into the PDT oxygen diffusion models for cell suspensions and cell monolayers. The time-dependent phosphorescence signals generated by the diffusion models are shown ...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Weston MA,Patterson MS

    更新日期:2014-11-01 00:00:00

  • Circadian gating of photoinduction of commitment to cell-cycle transitions in relation to photoperiodic control of cell reproduction in Euglena.

    abstract::A novel type of circadian and photoperiodic control of the cell division cycle was found in photoautotrophic Euglena gracilis. When algae entrained to 24 h light-dark (LD) cycles (14 h L) were transferred to continuous darkness (DD) at the eighth hour of the final LD photoperiod, cell-cycle transition was arrested in ...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Hagiwara SY,Bolige A,Zhang Y,Takahashi M,Yamagishi A,Goto K

    更新日期:2002-07-01 00:00:00

  • Construction and characterization of hybrid luciferases coded by lux genes from Xenorhabdus luminescens and Vibrio fischeri.

    abstract::Molecular cloning techniques were employed to obtain hybrid luciferases with their alpha and beta subunits encoded by luxA and luxB genes, respectively, from Xenorhabdus luminescens strain HW or Vibrio fischeri. Although the two wild-type luminous bacteria are phylogenetically diverged, the hybrid luciferase Xf compri...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Xi L,Tu SC

    更新日期:1993-04-01 00:00:00

  • The (α-4) photoconjugates of 5-methylcytosine, 1,5-dimethylcytosine, 1-methylthymine and thymidine.

    abstract::The pyrimidine nucleobases contained in DNA undergo a variety of photoinduced reactions in which two moieties become joined to form a product (e.g. formation of cyclobutane dimers and [6-4] adducts). Herein, we describe a new type of photoconjugation reaction that has been shown to occur for 5-methylcytosine (5-MeC), ...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Shetlar MD,Chung J

    更新日期:2012-03-01 00:00:00

  • Quenching enhancement of the singlet excited state of pheophorbide-a by DNA in the presence of the quinone carboquone.

    abstract::Changes in the emission fluorescence intensity of pheophorbide-a (PHEO) in the presence of carboquone (CARBOQ) were used to obtain the association constant, the number of CARBOQ molecules interacting with PHEO, and the fluorescence quantum yield of the complex. Excitation spectra of mixtures of PHEO and CARBOQ in etha...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Díaz-Espinosa Y,Crespo-Hernández CE,Alegría AE,García C,Arce R

    更新日期:2011-03-01 00:00:00

  • A comparison of fluorescence methods used in the pharmacokinetic studies of Zn(II)phthalocyanine in mice.

    abstract::The pharmacokinetics of Zn phthalocyanine (ZnPc) encapsulated in dipalmitoyl-phosphatidylcholine (DPPC) liposomes, injected intravenously in Skh:HR-1 nude mice, was monitored by two in vitro techniques and one in vivo technique, all based on fluorescence spectroscopy. The in vitro methods involve either fluorescence m...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Biolo R,Jori G,Kennedy JC,Nadeau P,Pottier R,Reddi E,Weagle G

    更新日期:1991-01-01 00:00:00

  • Wavelength dependence of histological, physical, and visible changes in chronically UV-irradiated hairless mouse skin.

    abstract::Albino hairless mice (Skh: HR-1) exposed chronically to sub-erythemal doses of UV radiation display physical, visible and histological alterations. Using narrow bandwidth radiation covering the UV radiation spectrum from 280-380 nm, the wavelength dependence of these alterations was determined. The wavelength dependen...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Bissett DL,Hannon DP,Orr TV

    更新日期:1989-12-01 00:00:00

  • Alkali-labile photolesions mapping to purine sites in ultraviolet-irradiated DNA.

    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

    pub_type: 杂志文章


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

    更新日期:1994-02-01 00:00:00

  • A mathematical evaluation of dose-dependent PpIX fluorescence kinetics in vivo.

    abstract::The in vivo pharmacokinetics of protoporphyrin IX (PpIX) after administration of 5-aminolevulinic acid (ALA) cannot be described accurately by mathematical models using first-order rate processes. We have replaced first-order reaction rates by dose-dependent (Michaelis-Menten [MM]) reaction rates in a mathematical com...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Aalders MC,van der Vange N,Star WM,Sterenborg HJ

    更新日期:2001-08-01 00:00:00

  • Dipole and oscillator strengths of chromophores in solution.

    abstract::A widely published expression for dipole strengths of optical transitions is found to require correction. The proposed adjustment, which involves the refractive index of the solvent in which the strengths are measured, may lead to significant changes in predictions that have been based on the equation. We discuss a cl...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Knox RS

    更新日期:2003-05-01 00:00:00

  • Protonation-state-Coupled Conformational Dynamics in Reaction Mechanisms of Channel and Pump Rhodopsins.

    abstract::Channel and pump rhodopsins use energy from light absorbed by a covalently bound retinal chromophore to transport ions across membranes of microbial cells. Ion transfer steps, including proton transfer, can couple to changes in protein conformational dynamics and water positions. Although general principles of how mic...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章,评审


    authors: Bondar AN,Smith JC

    更新日期:2017-11-01 00:00:00

  • Photophysical properties of the lowest excited singlet and triplet states of thio- and seleno-psoralens

    abstract::The decay processes of the lowest excited singlet and triplet states of five heteropsoralens (HPS) were investigated by steady-state and shift-phase fluorometry and by laser-flash photolysis in different solvents. The emission spectra of HPS are detectable only in trifluoroethanol (TFE), where fluorescence lifetimes (...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Aloisi GG,Elisei F,Moro S,Miolo G,Dall'Acqua F

    更新日期:2000-05-01 00:00:00

  • Therapeutic Enhancement of Verteporfin-mediated Photodynamic Therapy by mTOR Inhibitors.

    abstract::Photodynamic therapy (PDT) with photosensitizer verteporfin is a clinically approved vascular disrupting modality that is currently in clinical trial for cancer treatment. In this study, we evaluated PDT in combination with either mTORC1 inhibitor rapamycin or mTORC1/C2 dual inhibitor AZD2014 for therapeutic enhanceme...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Kraus D,Palasuberniam P,Chen B

    更新日期:2020-03-01 00:00:00

  • Chaetopterus variopedatus Bioluminescence: A Review of Light Emission within a Species Complex.

    abstract::Chaetopterus variopedatus has been studied for over a century in terms of its physiology, ecology and life history. One focus of research is on its intrinsic bioluminescent emissions, which can be observed as a blue light emitted from the extremities of individual body segments, or as a secreted mucus. Even though res...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章,评审


    authors: Mirza JD,Migotto ÁE,Yampolsky IV,de Moraes GV,Tsarkova AS,Oliveira AG

    更新日期:2020-07-01 00:00:00

  • Xanthene dyes induce membrane permeabilization of bacteria and erythrocytes by photoinactivation.

    abstract::We analyzed the photoinactivation of the membrane functions of bacteria and erythrocytes induced by xanthene dyes. The dyes tested were rose bengal, phloxine B, erythrosine B and eosin B. These dyes induced the leakage of K(+) from Staphylococcus aureus cells within minutes of photoirradiation, in the order of rose be...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Kato H,Komagoe K,Nakanishi Y,Inoue T,Katsu T

    更新日期:2012-03-01 00:00:00

  • Comparison of methylene blue and methylene violet for photoinactivation of intracellular and extracellular virus in red cell suspensions.

    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

    pub_type: 杂志文章


    authors: Skripchenko A,Robinette D,Wagner SJ

    更新日期:1997-03-01 00:00:00

  • Solar UV irradiation conditions on the surface of Mars.

    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

    pub_type: 杂志文章


    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

  • Photoreduction of Ru(bpy)(3)2+ by amines in aqueous solution. Kinetics characterization of a long-lived nonemitting excited state.

    abstract::The photochemistry of Ru(bpy)(3)+2 in the presence of amines was investigated in water by laser flash photolysis. N,N'-Dimethylaniline and p-phenylenediamine quench the luminescent metal to ligand charge transfer (MLCT) excited state of the complex by an electron transfer reaction that produces the semireduced form Ru...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Rivarola CR,Bertolotti SG,Previtali CM

    更新日期:2006-01-01 00:00:00

  • Photogenotoxicity of skin phototumorigenic fluoroquinolone antibiotics detected using the comet assay.

    abstract::The fluoroquinolone (FQ) antibiotics photosensitize human skin to solar UV radiation and are reported to photosensitize tumor formation in mouse skin. As tumor initiation will not occur without genotoxic insult, we examined the potential of ciprofloxacin, lomefloxacin, fleroxacin, BAYy3118 (a recently developed monofl...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Reavy HJ,Traynor NJ,Gibbs NK

    更新日期:1997-09-01 00:00:00

  • Light-sensitive intelligent drug delivery systems.

    abstract::Drug delivery systems (DDS) capable of releasing an active molecule at the appropriate site and at a rate that adjusts in response to the progression of the disease or to certain functions/biorhythms of the organism are particularly appealing. Biocompatible materials sensitive to certain physiological variables or ext...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章,评审


    authors: Alvarez-Lorenzo C,Bromberg L,Concheiro A

    更新日期:2009-07-01 00:00:00

  • Absorbance changes by aromatic amino acid side chains in early rhodopsin photointermediates.

    abstract::Absorbance changes were monitored from 250 to 650 nm during the first microsecond after photolysis of detergent suspensions of bovine rhodopsin at 20 degrees C. Global analysis of the resulting data produced difference spectra for bathorhodopsin, BSI and lumirhodopsin which give the change in absorbance of the aromati...

    journal_title:Photochemistry and photobiology

    pub_type: 杂志文章


    authors: Lewis JW,Jäger S,Kliger DS

    更新日期:1997-12-01 00:00:00