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 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.
journal_name
Photochem Photobioljournal_title
Photochemistry and photobiologyauthors
Golub AS,Popel AS,Zheng L,Pittman RNsubject
Has Abstractpub_date
1999-06-01 00:00:00pages
624-32issue
6eissn
0031-8655issn
1751-1097journal_volume
69pub_type
杂志文章abstract::Novel water-soluble polymeric photosensitizers (SPO) based on starch and containing porphyrin chromophores were synthesized and studied. The polymers were soluble in water and in dimethyl sulfoxide. Photophysical studies and solubilization of molecular probes proved the formation of hydrophobic, rigid microdomains in ...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1562/2005-03-07-RA-455
更新日期:2005-09-01 00:00:00
abstract::Photodamage to the endoplasmic reticulum (ER) can initiate a death pathway termed paraptosis. The "canonical" model of paraptosis, initiated by certain drugs and other stimuli, requires a brief interval of protein synthesis, involves the action of MAP kinases and can be followed by biochemical markers. The latter incl...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.13242
更新日期:2020-09-01 00:00:00
abstract::Vacuum UV (VUV) process is an incipient advanced oxidation process, which can be used for water treatment. This process relies on the formation of hydroxyl radicals through the VUV-induced photolysis of water. In particular, the use of ozone-generating mercury vapor lamps, which emit 10% of the radiation at 185 nm and...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12157
更新日期:2014-01-01 00:00:00
abstract::Within this study, the erythemal ultraviolet (UV) exposure received by different parts of the body during four different activities is determined. Optoelectronic devices were used to measure the erythemal UV exposure at 10 different positions of the body. The measuring devices were fixed on the forehead, on the should...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12085
更新日期:2013-07-01 00:00:00
abstract::The chloride effect on the photobleaching process of iodopsin, a chicken red-sensitive cone visual pigment, was studied in detail by time-resolved low-temperature spectroscopy at -40 degrees C to -10 degrees C. Decay-associated difference spectra obtained by kinetic analysis using the singular value decomposition meth...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2008.00332.x
更新日期:2008-07-01 00:00:00
abstract::Confocal laser microspectrofluorometric measurements on human T47D mammary tumor cells have been performed to assess the intracellular distribution of hypericin within the various cell compartments: cytoplasmic membrane, cytoplasm and nucleus. Confocal fluorescence measurements obtained from microvolumes (approximatel...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1995.tb02382.x
更新日期:1995-09-01 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
pub_type: 杂志文章
doi:10.1111/php.12219
更新日期:2014-05-01 00:00:00
abstract::Photoreduction of cytochrome c (Cyt c) has been reinvestigated using femtosecond-to-nanosecond transient absorption and stationary spectroscopy. Femtosecond spectra of oxidized Cyt c, recorded in the probe range 270-1000 nm, demonstrate similar evolution upon 266 or 403 nm excitation: an ultrafast 0.3 ps internal conv...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2007.00219.x
更新日期:2008-01-01 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
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1991.tb03638.x
更新日期:1991-03-01 00:00:00
abstract::An alkyne-terminated anthracene and azide-terminated carbazole were joined through a copper-catalyzed cycloaddition to form a joined donor/acceptor pair. The photonic pair exhibited energy transfer when excited at the peak absorbance of carbazole and fluoresced with an anthracene spectral response. The fluorescent beh...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2011.01023.x
更新日期:2012-01-01 00:00:00
abstract::Iranian firefly larvae, Lampyris turkestanicus collected from north of Iran and their luciferin were analyzed by HPLC, TLC, MS and spectroscopic Fourier transform ([FT]-IR, FT-NMR, UV and fluorescence) methods. The results showed that luciferin in L turkestanicus lanterns was the same as in the American firefly, Photi...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1996.tb01841.x
更新日期:1996-11-01 00:00:00
abstract::To determine the impact of delivery vehicles in photosensitizing efficacy of HPPH, a hydrophobic photosensitizer was dissolved in various formulations: 1% Tween 80/5% dextrose, Pluronic P-123 and Pluronic F-127 in 0.5%, 1% and 2% phosphate buffer solutions (PBS). HPPH was also conjugated to Pluronic F-127, and the res...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.13183
更新日期:2020-05-01 00:00:00
abstract::From June to September 2005, we carried out experiments to determine the ultraviolet radiation (UVR) -induced photoinhibition of summer phytoplankton assemblages from a coastal site of the South China Sea. Variability in taxonomic composition was determined throughout the summer, with a peak chlorophyll a (chl a appro...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2007.00154.x
更新日期:2007-07-01 00:00:00
abstract::δ-Aminolevulinic acid (ALA)-induced porphyrin accumulation is widely used in the treatment of cancer, as photodynamic therapy. To clarify the mechanisms of the tumor-preferential accumulation of protoporphyrin, we examined the effect of the expression of heme-biosynthetic and -degradative enzymes on the ALA-induced ac...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2011.00950.x
更新日期:2011-09-01 00:00:00
abstract::Sulfur-substituted nucleobases (a.k.a., thiobases) are among the world's leading prescriptions for chemotherapy and immunosuppression. Long-term treatment with azathioprine, 6-mercaptopurine and 6-thioguanine has been correlated with the photoinduced formation of carcinomas. Establishing an in-depth understanding of t...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章,评审
doi:10.1111/php.12975
更新日期:2019-01-01 00:00:00
abstract::To clarify the role of the Golgi apparatus in photodynamic therapy-induced apoptosis, its signaling pathway was studied after photodynamic treatment of human cervix carcinoma cell line HeLa, in which a photosensitizer, 2,4,5,7-tetrabromorhodamine 123 bromide (TBR), was incorporated into the Golgi apparatus. Laser scan...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1562/0031-8655(2003)078<0241:cacacb>2.0.co;2
更新日期:2003-09-01 00:00:00
abstract::Evidence is mounting that UV-B and UV-A radiation affect skin differently in responses as diverse as erythema and elastosis. We found in this study that collagen metabolism was also differentially affected. Albino hairless mice were irradiated with two UV-A sources: (1) UVASUN 3000 (340-400 nm) for cumulative exposure...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1991.tb02011.x
更新日期:1991-08-01 00:00:00
abstract::Excessive sun exposure can cause sunburn, suntan, skin photoaging, and even skin cancer. Skin photoaging conflicts with the human pursuit of a young and beautiful appearance. Some research data indicate that the incidence of skin cancer in the Chinese has been increasing, although it remains lower than in whites. To e...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12623
更新日期:2016-09-01 00:00:00
abstract::The photocycle in photoactive yellow protein (PYP) crystals was studied by single-crystal absorption spectroscopy with experimental setups for low-temperature and time-resolved measurements. Thin and flat PYP crystals, suitable for light absorption studies, were obtained using special crystallization conditions. Illum...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1562/0031-8655(2003)078<0131:copiic>2.0.co;2
更新日期:2003-08-01 00:00:00
abstract::Cryptococus gattii is an emergent primary human pathogen that causes meningismus, papilledema, high intracranial pressure and focal involvement of the central nervous system in immunocompetent hosts. Prolonged antifungal therapy is the conventional treatment, but it is highly toxic, selects for resistant strains, cont...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2010.00868.x
更新日期:2011-03-01 00:00:00
abstract::Positively charged zinc containing or metal free phthalocyanines 6a-c and 7a-c were prepared via a three step procedure starting from 4-nitrophthalonitrile. The phthalocyanines contain alkyl chains of different length in order to influence the hydrophilic vs lipophilic character of the compounds. The partition between...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.1990.tb01721.x
更新日期:1990-03-01 00:00:00
abstract::The maximum erythemal dose rate (EDRmax ) at the Earth's surface tends to occur at local noon. However, clouds can make the timing of EDRmax significantly away from local noon. In fact, EDRmax and its time of occurrence depend mainly on the solar zenith angle at noon (SZAn ), site's altitude, the total ozone column (T...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.13054
更新日期:2019-05-01 00:00:00
abstract::The thermodynamic parameters for the formation of the free radicals upon electron transfer quenching of the flavin triplet state (3FMN) by tryptophan and tyrosine, Delta(FR)H and Delta(FR)V, were obtained in aqueous solution by the application of laser-induced optoacoustic spectroscopy at various temperatures. The Del...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1562/2005-03-22-RA-468
更新日期:2006-01-01 00:00:00
abstract::In this paper, we propose a new physical method in combination with mixed solution of thiazone and polyethylene glycol 400 (thiazone PEG 400 solution) penetration into tissue to assess the skin optical clearing. Four treatments were performed: (1) control group (C); (2) polyethylene glycol 400 (PEG400); (3) 0.25% thia...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2010.00710.x
更新日期:2010-05-01 00:00:00
abstract::Seafarers working on decks of vessels at low latitudes are exposed to extremely high solar UV radiation. Their risk of developing skin cancer may be enhanced. Solar erythemal UV irradiance and exposure were measured for the first time on merchant vessels going along typical international routes at low latitudes. The m...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12144
更新日期:2013-11-01 00:00:00
abstract::The inefficient endosomal escape of drugs or macromolecules is a major obstacle to achieving successful delivery to therapeutic targets. An efficient approach to circumvent this barrier is photochemical internalization (PCI), which uses light and photosensitizers for endosomal escape of the delivered macromolecules. T...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.13146
更新日期:2019-11-01 00:00:00
abstract::Central venous catheters (CVC) are widely used in the United States and are associated with 250,000 to 500,000 CVC-related infections in hospitals annually. We used a catheter made from ultraviolet-C (UVC) transmissive material to test whether delivery of UVC from the lumen would allow inactivation of microorganisms o...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/j.1751-1097.2010.00819.x
更新日期:2011-01-01 00:00:00
abstract::Assignment of the fluorescence spectrum of firefly luciferin in aqueous solutions was achieved by utilizing not only emission energies but also theoretical absorption spectra and relative concentrations as estimated by pKa values. Calculated Gibbs free energies were utilized to estimate pKa values. These pKa values we...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12156
更新日期:2014-01-01 00:00:00
abstract::The incidence of skin cancer is increasing rapidly, particularly in the Caucasian population. Epidemiological and experimental studies demonstrated that ultraviolet radiation (UVR) is the primary cause for the increasing incidence of skin cancer. It is well known that UV irradiation induces DNA damage. If the damage i...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:
更新日期:1999-09-01 00:00:00
abstract::UVB radiation contributes to both direct and indirect damage to the skin including the generation of free radicals and reactive oxygen species (ROS), inflammatory responses, immunosuppression and gene mutations, which can ultimately lead to photocarcinogenesis. A plant-derived flavonoid, baicalin, has been shown to ha...
journal_title:Photochemistry and photobiology
pub_type: 杂志文章
doi:10.1111/php.12505
更新日期:2015-11-01 00:00:00