Substituent effects on the photophysical properties of pterin derivatives in acidic and alkaline aqueous solutions.

abstract：:Solar radiation is known to be a major contributor to the development of skin cancer. Most sunscreen formulations, including those with broad spectrum, offer minimal protection in long-wavelength ultraviolet A1 (UVA1; 370-400 nm) and visible light (VL; 400-700 nm) domain. There is limited information regarding the imp...

journal_title：Photochemistry and photobiology

authors： Kohli I,Zubair R,Lyons AB,Nahhas AF,Braunberger TL,Mokhtari M,Ruvolo E,Lim HW,Hamzavi IH

更新日期：2019-11-01 00:00:00

abstract：:The photochemical reactions of the 1-deaza derivative of riboflavin (RF) have been studied by sub-ps time-resolved fluorescence spectroscopy. A potential effect of the solvent polarity and hydrogen bonding capability on the excited state (ES) dynamics was tested by measuring 1-deaza RF in water and, after acetylation ...

journal_title：Photochemistry and photobiology

authors： Slavov C,Mansurova M,Holzwarth AR,Gärtner W

更新日期：2010-01-01 00:00:00

abstract：:This paper studies the dye-sensitized photooxidation of tyrosine (tyr) and tyr di- and tripeptides (tyr-tyr and tyr-tyr-tyr) mediated by singlet molecular oxygen (O2[1 delta g]) in alkaline media. Photooxidation quantum efficiencies (phi r) were obtained by determining the overall and reactive rate constants of intera...

journal_title：Photochemistry and photobiology

authors： Criado S,Soltermann AT,Marioli JM,García NA

更新日期：1998-10-01 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：:N2-hydroxyisocytosine and 1-methyl-N2-hydroxyisocytosine were studied using a matrix isolation technique combined with infrared absorption spectroscopy. For N2-hydroxyisocytosine isolated in an Ar matrix (at 10 K), two imino-oxo isomers, one with the hydroxyimino =N-OH group directed toward the N1-H group (the form ca...

journal_title：Photochemistry and photobiology

authors： Lapinski L,Nowak MJ,Kwiatkowski JS,Leszczynski J

更新日期：2003-03-01 00:00:00

abstract：:Lymphocytes treated with delta-aminolevulinic acid (ALA) can accumulate the photoactive, fluorescent heme precursor, protoporphyrin IX (PpIX). With visible light illumination, PpIX can be used in photodynamic therapy (ALA-PDT) to kill or functionally alter cells. The aim of this study was to characterize the effects o...

journal_title：Photochemistry and photobiology

authors： Hryhorenko EA,Rittenhouse-Diakun K,Harvey NS,Morgan J,Stewart CC,Oseroff AR

更新日期：1998-05-01 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 progressive loss of visual faculties with advancing age is attributed, sometimes, mainly to allegedly inevitable optical deterioration, such as clouding of the media, or again to neurosenescence, as typified by cell-death. The relevant factors are assessed, and it is not thought likely that changes in normal ocula...

journal_title：Photochemistry and photobiology

authors： Weale RA

更新日期：1989-09-01 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：:The binding interactions of three naphthalimide derivatives with heteropoly nucleic acids have been evaluated using fluorescence, absorption and circular dichroism spectroscopies. Mono- and bifunctionalized naphthalimides exhibit sequence-dependent variations in their affinity toward DNA. The heteropoly nucleic acids,...

journal_title：Photochemistry and photobiology

authors： McMasters S,Kelly LA

更新日期：2007-07-01 00:00:00

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

authors： Rakshit S,Goswami N,Pal SK

更新日期：2012-01-01 00:00:00

abstract：:The mechanism of caspase-3-dependent apoptosis induced by photodynamic therapy (PDT) of cultured Chinese hamster V79 cells with pheophorbide a (PPa) was investigated. The PPa-PDT induced rapid apoptosis within 30 min after irradiation of cells. This apoptosis was inhibited by the 1O2 quencher N3- and caspase-3 inhibit...

journal_title：Photochemistry and photobiology

authors： Inanami O,Yoshito A,Takahashi K,Hiraoka W,Kuwabara M

更新日期：1999-10-01 00:00:00

abstract：:The tetraruthenated porphyrin, mu-[meso-5,10,15,20-tetra(pyridyl)porphyrin]tetrakis[bis-(bipyridine) chloride ruthenium(II)] (TRP) is a supramolecular cationic species. The aim of the present investigation was to evaluate the photodynamic properties of TRP and Zn-TRP to damage DNA with emphasis on the mechanistic aspe...

journal_title：Photochemistry and photobiology

authors： Ravanat JL,Cadet J,Araki K,Toma HE,Medeiros MH,Mascio PD

更新日期：1998-11-01 00:00:00

abstract：:Many viral infections reach clinical significance in winter, when it is cold, relative humidity is lowest and vitamin D production from solar ultraviolet-B irradiation is at its nadir. Several autoimmune diseases, such as multiple sclerosis, type 1 diabetes mellitus and asthma, are linked to viral infections. Vitamin ...

journal_title：Photochemistry and photobiology

authors： Grant WB

更新日期：2008-03-01 00:00:00

abstract：:Paracoccidioidomycosis is the most prevalent human mycosis in Latin America. Cutaneous lesions are extremely painful and sensitive, and current treatment with antifungal drugs is lengthy and may cause side effects to patients. In this perspective, the helium-neon (HeNe) laser emerges as a novel therapy form due to its...

journal_title：Photochemistry and photobiology

authors： Nagib PR,Gameiro J,da Costa TA,Di Gangi R,Ribeiro Jda S,Paulino LC,Verinaud L

更新日期：2010-07-01 00:00:00

abstract：:A 2-year field study on the effect of different light environments, obtained by using cladding materials (polyethylene films and shade net) able to cut off specific regions of the photosynthetically active radiation and ultraviolet wavebands, on the growth and phenylpropanoids content of Achillea collina grown in the ...

journal_title：Photochemistry and photobiology

authors： Giorgi A,Manzo A,Vagge I,Panseri S

更新日期：2014-01-01 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

authors： Silva AA,Yamamoto ALC,Corrêa MP

更新日期：2019-05-01 00:00:00

abstract：:Antibodies and antigen binding fragments thereof were photochemically immobilized on surface-modified silicon chips of 5 x 5 mm size. Silicon surface-grafted diazirines and benzophenones formed covalent bonds with the immunoreagents on light activation. Photolithographic immobilization of monoclonal antibodies in aque...

journal_title：Photochemistry and photobiology

authors： Sundarababu G,Gao H,Sigrist H

更新日期：1995-06-01 00:00:00

abstract：:The photodegradation of the S(+)- and R(-)-ketoprofen (KP) enantiomers in the bovine serum albumin matrix was studied by steady-state photolysis with the use of lambda(irr) > 320 nm and transient absorption spectroscopy with lambda(exc) = 355 nm, at 1/1 and 2/1 KP/BSA molar ratios. R(-)-KP was found to be more labile ...

journal_title：Photochemistry and photobiology

authors： Monti S,Manet I,Manoli F,Morrone R,Nicolosi G,Sortino S

更新日期：2006-01-01 00:00:00

abstract：:Skin cancer is the most prevalent cancer, and its assessment remains a challenge for physicians. This study reports the application of an optical sensing method, elastic scattering spectroscopy (ESS), coupled with a classifier that was developed with machine learning, to assist in the discrimination of skin lesions th...

journal_title：Photochemistry and photobiology

authors： Rodriguez-Diaz E,Manolakos D,Christman H,Bonning MA,Geisse JK,A'Amar OM,Leffell DJ,Bigio IJ

更新日期：2019-11-01 00:00:00

abstract：:An important step in predicting the effects of future increases in UV radiation (UVR) is to evaluate the mechanisms that organisms use to prevent and repair DNA damage and determine how those mechanisms influence UVR sensitivity. Damage is prevented to varying degrees through photoprotection and repaired via two main ...

journal_title：Photochemistry and photobiology

authors： Olson MH,Mitchell DL

更新日期：2006-03-01 00:00:00

abstract：:Aqueous solutions of KI were examined for use as chemical actinometers to measure 254 nm (germicidal) radiation. Irradiation results in electron ejection from iodide such that aqueous electrons and iodine atoms are formed. In the presence of N2O, an electron scavenger, recombination of these two reactive species is el...

journal_title：Photochemistry and photobiology

authors： Rahn RO

更新日期：1993-12-01 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：: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

authors： Neale P

更新日期：2013-07-01 00:00:00

abstract：:The energetic characteristics of selected reaction steps in the bacterial luciferase-catalyzed luminescence reaction were examined by computation using the MNDO-PM3 method. Specifically, a three-step model was proposed to account for the reaction between oxygen and reduced riboflavin 5'-phosphate (1,5H2-FMN) to genera...

journal_title：Photochemistry and photobiology

authors： Wada N,Sugimoto T,Watanabe H,Tu SC

更新日期：1999-07-01 00:00:00

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

authors： Lewis JW,Jäger S,Kliger DS

更新日期：1997-12-01 00:00:00

abstract：:The blue light photoreceptor phototropin mediates crucial processes in plants leading to optimization of photosynthesis. Phototropin comprises two flavin mononucleotide-binding LOV (light-, oxygen-, or voltage-sensitive) domains. The LOV domains undergo a photocycle upon illumination, in which two intermediates have b...

journal_title：Photochemistry and photobiology

authors： Bauer C,Rabl CR,Heberle J,Kottke T

更新日期：2011-05-01 00:00:00

abstract：:The octahedral rhodium complex, cis-dichloro bis(1,10 phenanthroline)rhodium(III) chloride (BISPHEN), is known to form covalent linkages with DNA involving the attachment of the metal to a base. In order to determine the sequence selectivity of this chemistry, solutions of the complex containing one of the double-stra...

journal_title：Photochemistry and photobiology

authors： Morrison H,Harmon H

更新日期：2000-12-01 00:00:00

abstract：:Phage T7 can be used as a biological UV dosimeter. Its reading is proportional to the inactivation rate expressed in HT7 units. To understand the influence of phage proteins on the formation of DNA UV photoproducts, cyclobutane pyrimidine dimers (CPD) and (6-4)photoproducts ((6-4)PD) were determined in T7 DNA exposed ...

journal_title：Photochemistry and photobiology

authors： Fekete A,Vink AA,Gaspar S,Modos K,Berces A,Ronto G,Roza L

更新日期：1999-05-01 00:00:00

abstract：:Urban environments can have high-risk spaces that can provide excess personal sun exposure, such as urban or street canyons, and the spaces between buildings, among others. In these urban spaces, sun exposure can be high or low depending on several factors. Polysulphone film (PSF) was used to assess possible daily sol...

journal_title：Photochemistry and photobiology

authors： Wright CY,du Preez DJ,Martincigh BS,Allen MW,Millar DA,Wernecke B,Blesic S

更新日期：2020-09-01 00:00:00