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

abstract：:The growing resistance to antibiotics has rendered antimicrobial photodynamic inactivation (PDI) an attractive alternative treatment modality for infectious diseases. Chitosan (CS) was shown to further potentiate the PDI effect of photosensitizers and was therefore used in this study to investigate its ability to pote...

journal_title：Photochemistry and photobiology

authors： Chen CP,Chen CT,Tsai T

更新日期：2012-05-01 00:00:00

abstract：:We study the fluorescence lifetime of the well-known 1-pyrene butyric acid (PBA) to assess oxygen concentrations in living cells. The behavior of the probe is first studied in water, ethanol, protein solution and liposome suspension. The Stern-Volmer plot of these solutions is linear, and the bimolecular reaction rate...

journal_title：Photochemistry and photobiology

authors： Ribou AC,Vigo J,Salmon JM

更新日期：2004-09-01 00:00:00

abstract：:Carp (Cyprinus carpio) were repeatedly exposed to 0, 60, 120 and 240 mJ/cm2 ultraviolet B (UVB) radiation three times in 1 week (short-term exposure) or 12 times in 4 weeks (long-term exposure). The effect of UVB on the functioning of the carp immune system was studied on day 2 after the final irradiation. After short...

journal_title：Photochemistry and photobiology

authors： Markkula SE,Salo HM,Immonen AK,Jokinen EI

更新日期：2005-05-01 00:00:00

abstract：:By a technique which combines rapid mixing of cells and hematoporphyrin (HP) with a short duration of illumination, the photodynamic inactivation of yeast cells was investigated, particularly, in seeking for the information of the location of HP at the time of action. The fluence-survival curves obtained under the con...

journal_title：Photochemistry and photobiology

authors： Ito T

更新日期：1981-10-01 00:00:00

abstract：:The proton channels of the bacteriorhodopsin (BR) proton pump contain bound water molecules. The channels connect the purple membrane surfaces with the protonated retinal Schiff base at the membrane center. Films of purple membrane equilibrated at low relative humidity display a shift of the 570 nm retinal absorbance ...

journal_title：Photochemistry and photobiology

authors： Renthal R,Gracia N,Regalado R

更新日期：2000-11-01 00:00:00

abstract：:The photodynamic effect of hypericin on EMT6 mouse mammary carcinoma cells was investigated in vitro under aerobic and hypoxic conditions. Under aerobic conditions, hypericin-induced photocytotoxicity was dose dependent within a 1-50 microM range. Under hypoxic conditions, cells were resistant to hypericin-induced pho...

journal_title：Photochemistry and photobiology

authors： Thomas C,Pardini RS

更新日期：1992-06-01 00:00:00

abstract：:The present work is aimed to synthesize CdTe/ZnSe core/shell quantum dots (QDs) in an easy way and to explore the possibilities of its application in in vitro imaging of chicken tissue and embryo. The QDs were prepared using microwave irradiation with different temperatures, which is a very easy and less time-consumin...

journal_title：Photochemistry and photobiology

authors： Moulick A,Blazkova I,Milosavljevic V,Fohlerova Z,Hubalek J,Kopel P,Vaculovicova M,Adam V,Kizek R

更新日期：2015-03-01 00:00:00

abstract：:Solar ultraviolet B (UVB) radiation has been shown to induce inflammation, DNA damage, p53 mutations and alterations in signaling pathways eventually leading to skin cancer. In this study, we investigated whether fisetin reduces inflammatory responses and modulates PI3K/AKT/NFκB cell survival signaling pathways in UVB...

journal_title：Photochemistry and photobiology

authors： Pal HC,Athar M,Elmets CA,Afaq F

更新日期：2015-01-01 00:00:00

abstract：:The quenching of the benzophenone triplet by lysozyme and its constituent amino acids in aqueous solutions have been studied. Native lysozyme quenches the benzophenone triplet with a high rate constant, 4 x 10(9) M-1 s-1. The quenching process takes place with production of significant amounts of free ketyl radicals, ...

journal_title：Photochemistry and photobiology

authors： Encinas MV,Lissi EA,Vasquez M,Olea AF,Silva E

更新日期：1989-05-01 00:00:00

abstract：:On direct photoexcitation, subpicosecond time-resolved absorption spectroscopy revealed that the 1B(u)-type singlet excited state of all-trans-lycopene in chloroform was about seven times more efficient than all-trans-beta-carotene in generating the radical cation. The time constant of radical cation generation from t...

journal_title：Photochemistry and photobiology

authors： Han RM,Wu YS,Feng J,Ai XC,Zhang JP,Skibsted LH

更新日期：2004-09-01 00:00:00

abstract：:In this work, we have quantified for the first time the fluorescence and singlet oxygen quantum yields of a silicon(IV) phthalocyanine bound to the surface of zeolite L nanocrystals. The photophysical properties were correlated with the absorption spectra and the morphology of the nanoparticles, and most importantly, ...

journal_title：Photochemistry and photobiology

authors： Grüner M,Siozios V,Hagenhoff B,Breitenstein D,Strassert CA

更新日期：2013-11-01 00:00:00

abstract：:A novel Cs0.33 WO3 /LDHs (CWLDH) composite was synthesized by simple two steps solvothermal method and first investigated as the photocatalyst for tetracycline (TC) and Congo red (CR) degradation under visible light irradiation. The CWLDH heterostructures catalysts were characterized by XRD, UV-Vis, SEM, XPS and BET. ...

journal_title：Photochemistry and photobiology

authors： Zhang D,Ji T,Yu J,Jiang X,Jiao F

更新日期：2018-03-01 00:00:00

abstract：:During the past several years there has been debate about the origins of nonexponential intensity decays of intrinsic tryptophan (trp) fluorescence of proteins, especially for single tryptophan proteins (STP). In this review we summarize the data from diverse sources suggesting that time-dependent spectral relaxation ...

journal_title：Photochemistry and photobiology

authors： Lakowicz JR

更新日期：2000-10-01 00:00:00

abstract：:Photocatalytic degradation of methyl orange (MO) as a model of an organic pollution was accomplished with magnetic and porous TiO(2)/ZnO/Fe(3)O(4)/PANI and ZnO/Fe(3)O(4)/PANI nanocomposites under visible light irradiation. The structures of nanocomposites were characterized by various techniques including UV-Vis absor...

journal_title：Photochemistry and photobiology

authors： Nabid MR,Sedghi R,Gholami S,Oskooie HA,Heravi MM

更新日期：2013-01-01 00:00:00

abstract：:The classic method of photometric curves for photosensitivity determination has been extended to the case of photoreversible reactions and applied to the octopus rhodopsin --> acid metarhodopsin photoreaction. In such cases, measurements at one irradiation wavelength yield the sum of the photosensitivities of the forw...

journal_title：Photochemistry and photobiology

authors： Dixon SF,Cooper A

更新日期：1987-07-01 00:00:00

abstract：:Tetraarylporphyrins substituted with nitro groups at beta-pyrrolic positions are potential candidates for electron-accepting pigments in model systems for photosynthesis. The photophysics of 2-nitro-5,10,15,20-tetra-p-tolylporphyrin and its zinc analog have been studied in order to evaluate this potential. The ground ...

journal_title：Photochemistry and photobiology

authors： Gust D,Moore TA,Luttrull DK,Seely GR,Bittersmann E,Bensasson RV,Rougée M,Land EJ,De Schryver FC,Van der Auweraer M

更新日期：1990-04-01 00:00:00

abstract：:Continuous red light controls starch degradation in turions of Spirodela polyrhiza [Dölger, K., U. K. Tirlapur and K.-J. Appenroth [1997] Photochem. Photobiol. 66, 126-127 (1997)]. This light could be replaced by repeated red light pulses with the reciprocity law fulfilled over a large range of fluence rates. The effe...

journal_title：Photochemistry and photobiology

authors： Appenroth KJ,Gabrys H

更新日期：2001-01-01 00:00:00

abstract：:It has been proposed that photodegradation of folates may be the reason for the pigmentation of races living under high fluence rates of ultraviolet radiation. The photodegradation of folic acid (FA) induced by ultraviolet-A (UV-A) radiation, in solution and in the presence of human serum albumin (HSA), was studied wi...

journal_title：Photochemistry and photobiology

authors： Vorobey P,Steindal AE,Off MK,Vorobey A,Moan J

更新日期：2006-05-01 00:00:00

abstract：:Several antibacterial halogenated salicylanilides, including 3,3',4',5-tetrachlorosalicylanilide (TCSA) and 3,4',5-tribromosalicylanilide (TBSA) are known to cause photoallergy. We have carried out photochemical and spin trapping studies to determine whether free radicals may be involved in the photoallergic response....

journal_title：Photochemistry and photobiology

authors： Chignell CF,Sik RH

更新日期：1989-09-01 00:00:00

abstract：:Ultraviolet radiation can inhibit immune responses locally as well as systemically. Such effects have been measured in animals and humans exposed to ultraviolet B (wavelength 280-315 nm) (UVB) and ultraviolet A (315-400 nm) (UVA). The precise wavelength dependence is important for the identification of possible molecu...

journal_title：Photochemistry and photobiology

authors： Garssen J,de Gruijl F,Mol D,de Klerk A,Roholl P,Van Loveren H

更新日期：2001-04-01 00:00:00

abstract：:As a new class of sequence-specific regulators of gene expression, the microRNAs (miRNA) form a regulatory network with growth factors and transcription factors participating in various biological processes. It is now being recognized that the various key processes involved in cancer induction are under the control of...

journal_title：Photochemistry and photobiology

authors： Syed DN,Lall RK,Mukhtar H

更新日期：2015-01-01 00:00:00

abstract：:Catalases are oxidized by singlet oxygen giving rise to more acidic conformers detected in zymograms after electrophoresis in polyacrylamide gels. This shift in catalase mobility can be indicative of singlet oxygen production in vivo. Catalase from human cells, as from many organisms, is susceptible to in vitro modifi...

journal_title：Photochemistry and photobiology

authors： Lledías F,Hansberg W

更新日期：1999-12-01 00:00:00

abstract：:This paper reviews briefly the evidence for an association between various measures of UV radiation (UVR) exposure and the development of cancer. Issues such as data quality, study design, measurement variation, comparability of studies, and quantification of UV exposure in relation to skin cancer are discussed. A ran...

journal_title：Photochemistry and photobiology

authors： Berwick M,Kesler D

更新日期：2005-11-01 00:00:00

abstract：:Blue visible light damage to retinal pigment epithelial cells occurs through a photooxidative mechanism and the resultant damage is hypothesized to induce or exacerbate age-related macular degeneration. The purpose of the present study was to identify changes in the cell growth and the expression of hepatocyte growth ...

journal_title：Photochemistry and photobiology

authors： Chu R,Zheng X,Chen D,Hu DN

更新日期：2006-09-01 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：:Herein, we present a comparative study about the photoinactivation of Staphylococcus aureus (Gram-positive model) and Escherichia coli (Gram-negative model) employing a neutral and a dicationic axially functionalized SiIV -phthalocyanine. Depending on the charge of the siloxane moiety (neutral monosaccharide or cation...

journal_title：Photochemistry and photobiology

authors： Grüner MC,Niemann S,Faust A,Strassert CA

更新日期：2018-09-01 00:00:00

abstract：:Flash-induced absorbance spectroscopy was used to analyze the proton uptake and electron transfer properties of photosynthetic reaction centers (RC) of Rhodobacter capsulatus that have been genetically modified near the primary quinone electron acceptor (Q(A)). M246Ala and M247Ala, which are symmetry-related to the po...

journal_title：Photochemistry and photobiology

authors： Tandori J,Miksovska J,Valerio-Lepiniec M,Schiffer M,Maróti P,Hanson DK,Sebban P

更新日期：2002-02-01 00:00:00

abstract：:In this work, the changes in isoflavone levels and the expression of genes involved in their biosynthesis were studied in two Astragalus by UPLC-MS and real-time PCR after 10 days of UV-B treatment (λmax  = 313 nm, 804 J m-2 ). Isoflavones were significantly induced by UV-B irradiation. The influence might be activate...

journal_title：Photochemistry and photobiology

authors： Liu Y,Liu J,Wang Y,Abozeid A,Tian DM,Zhang XN,Tang ZH

更新日期：2018-01-01 00:00:00

abstract：:A 24 h preculture of HT29-18 human colonic adenocarcinoma cells with the sterol synthesis inhibitor lovastatin at concentrations of 0.1-0.5 microM markedly increased the photocytotoxic effect of photofrin II delivered to cells by low density lipoproteins. Under the same conditions, LDL binding and photofrin II (PII) u...

journal_title：Photochemistry and photobiology

authors： Biade S,Mazière JC,Mora L,Santus R,Mazière C,Auclair M,Morlière P,Dubertret L

更新日期：1993-02-01 00:00:00

abstract：:Low-level light therapy has been used in health care as a therapeutic strategy for different diseases. However, its effects on cancer are controversial. This work evaluated the effects of three energies on breast cancer-bearing mice after a single red light-emitting diode (LED) irradiation. 4T1 cells were inoculated i...

journal_title：Photochemistry and photobiology

authors： Pereira ST,Silva CR,Nuñez SC,Ribeiro MS

更新日期：2020-10-03 00:00:00