Abstract:
:Effects of solvent, pH and hydrogen bonding with N-methylimidazole (MIm) on the photophysical properties of 1-hydroxyfluorenone (1HOF) have been studied. Fluorescence lifetime, fluorescence quantum yield and triplet yield measurements demonstrated that intersystem crossing was the dominant process in apolar media and its rate constant significantly diminished with increasing solvent polarity. The acceleration of internal conversion in alcohols paralleled the strength of intermolecular hydrogen bonding. The faster energy dissipation from the singlet-excited state in cyclohexane was attributed to intramolecular hydrogen bonding. The pK(a) of 1HOF decreased from 10.06 to 5.0 on light absorption, and H(3)O(+) quenched the singlet-excited molecules in a practically diffusion-controlled reaction. On addition of MIm in toluene, dual fluorescence was observed, which was attributed to reversible formation of excited hydrogen-bonded ion pair. Rate constants for the various deactivation pathways were derived from the combined analysis of the steady-state and the time-resolved fluorescence results.
journal_name
Photochem Photobioljournal_title
Photochemistry and photobiologyauthors
Sebok-Nagy K,Biczók L,Morimoto A,Shimada T,Inoue Hdoi
10.1562/2004-01-27RA-067.1subject
Has Abstractpub_date
2004-07-01 00:00:00pages
119-26eissn
0031-8655issn
1751-1097pii
2004-01-27RA-067journal_volume
80pub_type
杂志文章abstract::Exploration of environmental dynamics using intrinsic biological probe tryptophan is very important; however, it suffers from various difficulties. An alternative probe, kynurenine (KN), has been found to be an efficient probe for the ultrafast dynamics in the biological environment (Goswami et al., [2010] J. Phys. Ch...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2011.01007.x
更新日期:2012-01-01 00:00:00
abstract::Plant responses to light spectral quality can be exploited to deliver a range of agronomically desirable end points in protected crops. This can be achieved using plastics with specific spectral properties as crop covers. We have studied the responses of a range of crops to plastics that have either (a) increased tran...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1562/2004-12-06-RA-392
更新日期:2005-09-01 00:00:00
abstract::Muscle injuries represent ca 30% of sports injuries and excessive stretching of muscle causes more than 90% of injuries. Currently the most used treatments are nonsteroidal anti-inflammatory drugs (NSAIDs), however, in last years, low-level laser therapy (LLLT) is becoming an interesting therapeutic modality. The aim ...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2012.01236.x
更新日期:2013-03-01 00:00:00
abstract::Polysulphone (PS) dosimetry has been a widely used technique for more than 30 years to quantify the erythemally effective UV dose received by anatomic sites (personal exposure). The calibration of PS dosimeters is an important issue as their spectral response is different from the erythemal action spectrum. It is perf...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2011.01006.x
更新日期:2012-01-01 00:00:00
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
doi:10.1562/0031-8655(2000)071<0506:ppotle>2.0.co;2
更新日期:2000-05-01 00:00:00
abstract::Structure-activity relationships have been widely reported for porphyrin and phthalocyanine photosensitizers, but not for phenothiazinium derivatives. Here, four phenothiazinium salts (methylene blue, toluidine blue O, 1,9-dimethyl methylene blue and the pentacyclic derivative DO15) were used to investigate how the ab...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12264
更新日期:2014-07-01 00:00:00
abstract::alpha-Crystallin, a major protein of the mammalian lens, plays a vital role in maintaining the structural stability and transparency of the lens. It performs this function through chaperone-like activity; it has recently been reported that heating alpha-crystallin enhances this ability. The present studies, using both...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1562/0031-8655(2000)071<0470:haceot>2.0.co;2
更新日期:2000-04-01 00:00:00
abstract::Systemic injection of hematoporphyrin derivative (HpD) in contribution with visible light (red or blue-green) delivered by laser was used to treat a patient with psoriasis. The psoriatic lesions responded vigorously to laser treatments, forming eschars by 1 week post irradiation. In contrast, only minimal erythema was...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1987.tb04739.x
更新日期:1987-07-01 00:00:00
abstract::This article is a highlight of the study by Stamenkovic and Hanelt in this issue of Photochemistry and Photobiology describing the high-irradiance photophysiology of several strains of freshwater chlorophyte microalgal genus, Cosmarium. These strains exhibit distinct differences in how combined thermal- high irradianc...
journal_title:Photochemistry and photobiology
pub_type: 评论,杂志文章
doi:10.1111/php.12081
更新日期:2013-07-01 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
pub_type: 杂志文章
doi:10.1111/php.12843
更新日期:2018-01-01 00:00:00
abstract::Intracellular targets for the photosensitizer alpha-terthienyl (alpha T) were examined by fluorescence microscopy and microfluorospectrometry using human nonkeratinized buccal cells. Intracellular distribution of alpha T was observed as fluorescent patches widely dispersed in the cytoplasm. The distribution of the flu...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1993.tb09213.x
更新日期:1993-05-01 00:00:00
abstract::Singlet oxygen reacts preferentially with three amino acids in proteins, His, Trp and Met. In order to study the specific molecular events that result from such oxidations, calf alpha-crystallin was photooxidized in the presence of uroporphyrin and the reactions were investigated by high performance liquid chromatogra...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1993.tb02330.x
更新日期:1993-03-01 00:00:00
abstract::Ultraviolet germicidal irradiation (UVGI) for air disinfection applications has relied on low-pressure mercury vapor lamps for decades. New design requirements have generated the need for alternatives in some uses. This study describes the current state of UVGI technology and describes future directions for technology...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章,评审
doi:10.1111/php.12080
更新日期:2013-07-01 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
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1989.tb08424.x
更新日期:1989-05-01 00:00:00
abstract::Alignment of the primary structures of the hydrozoan photoproteins, aequorin, mitrocomin, clytin and obelin showed very strong amino acid sequence identities. The Ca(2+)-binding sites of the proteins were found to be highly conserved. The Ca(2+)-binding sites were also homologous to the Ca(2+)-binding sites of other C...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1995.tb08713.x
更新日期:1995-10-01 00:00:00
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
doi:
更新日期:2004-01-01 00:00:00
abstract::Antisense oligodeoxynucleotides directed against a 24-mer RNA derived from the long terminal repeat (LTR) region of HIV were linked to proto- and methylpyrroporphyrin and their zinc derivatives. The oligonucleotide-porphyrin conjugates were tested for their ability to induce photodamage on the target RNA. Upon hybridi...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1994.tb05110.x
更新日期:1994-10-01 00:00:00
abstract::To improve the understanding of human skin autofluorescence emission, the spectroscopic and microscopic characteristics of skin autofluorescence were studied using a combined fluorescence and reflectance spectroanalyzer and a fiber optic microspectrophotometer. The autofluorescence spectra of in vivo human skin were m...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1995.tb09881.x
更新日期:1995-06-01 00:00:00
abstract::Targeted mutagenesis and gene knock-out can be mediated by triple helix-forming oligonucleotides (TFO) linked to mutagenic agents, such as psoralen. However, this strategy is limited by the availability of homopurine/homopyrimidine stretches at or near the target site because such sequences are required for high-affin...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:
更新日期:1998-03-01 00:00:00
abstract::Various photosensitizers were grafted by conventional peptide coupling methods to functionalized silica with several macroscopic shapes (powders, films) or embedded in highly transparent and microporous silica xerogel monoliths. Owing to the transparency and free-standing shape of the monoliths, the transient species ...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12166
更新日期:2014-03-01 00:00:00
abstract::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...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:
更新日期:1999-06-01 00:00:00
abstract::Accurate determination of the diurnal variability and daily insolation of surface (0(+) ) and subsurface (0(-) ) irradiance are essential to estimate several physical, chemical and biological processes occurring at the surface layer of marine environments. Natural downwelling PAR and spectral UVR were examined on eigh...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12474
更新日期:2015-09-01 00:00:00
abstract::Syntheses for the new photosensitizers HOSiPcOSi(CH3)2(CH2)3N(CH1)1 or 3(CH3)2, Pc 34 and Pc 25, have been developed and the order of activity of these photosensitizers and the previously reported photosensitizer Pc 4, HOSiPcOSi(CH3)2(CH2)3N(CH3)2, in the dark and with broad-band red light toward Plasmodium falciparum...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1997.tb08656.x
更新日期:1997-08-01 00:00:00
abstract::The bimolecular rate constants (k) of quenching of molecular singlet oxygen 1O2 (1 delta g) by organo-selenium compounds exhibiting glutathione peroxidase activity and by sulfur analogs have been determined by time resolved phosphorescence detection of 1O2 in CD3OD and C6D6, with no solvent effect. The rate constants ...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1991.tb02082.x
更新日期:1991-11-01 00:00:00
abstract::Efficient phagocytosis of photoreceptor outer segments (POS) membranes by retinal pigment epithelium (RPE) plays a key role in biological renewal of these highly peroxidizable structures. Here, we tested whether photodynamic treatment, mediated by merocyanine 540 (MC 540), rose Bengal or a zinc-substituted chlorophyll...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2010.00727.x
更新日期:2010-07-01 00:00:00
abstract::The photophysical properties of Piroxicam, a nonsteroidal anti-inflammatory drug (NSAID), were investigated at different pHext values in reversed micelles of Aerosol-OT (AOT) in iso-octane, using both steady-state and picosecond time-resolved fluorescence spectroscopy. In contrast with the very complex data obtained i...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:
更新日期:2000-04-01 00:00:00
abstract::High temperature can promote cyanobacterial blooms, whereas ultraviolet radiation (UVR) can potentially depress cyanobacterial growth by damaging their photosynthetic apparatus. Although the damaging effect of UVR has been well documented, reports on the interactive effects of UV radiation exposure and warming on cyan...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.13377
更新日期:2021-01-04 00:00:00
abstract::Tin oxide nanoparticles about 4 nm in size were successfully synthesized using hydrothermal method. The photocatalytic activity of the particles was determined by the decolorization of malachite green (MG) and titanium yellow (TY) under UV light. 12 ppm of MG and TY were used for the solution with an initial volume of...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2010.00863.x
更新日期:2011-03-01 00:00:00
abstract::The in vitro cell survival, localization and ultrastructural changes following irradiation were examined in 9L glioma cells sensitized with a new photosensitizer, lysyl chlorin p6 (LCP). In clonogenic assays, LCP was 10-100-fold more phototoxic than photofrin II on a microgram/mL basis. Lysyl chlorin p6 uptake was blo...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1993.tb04948.x
更新日期:1993-11-01 00:00:00
abstract::The wavelength dependence of an ultraviolet irradiation of the DNA substrate for a human endonuclease was determined. Sites of DNA incision for all UVB and UVC wavelengths examined were at cytosines which were neither cyclobutane pyrimidine dimers nor 6-4'-(pyrimidin-2-one)pyrimidines. The optimal wavelengths for form...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1989.tb04120.x
更新日期:1989-03-01 00:00:00