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Photochemical & Photobiological Sciences

Brian Diffey, Uli Osterwalder
Limited evidence exists to indicate that sunscreen protection factors determined in the laboratory are higher than those in natural sunlight. In this article we propose an explanation for this difference and estimate the expected SPFs of sunscreen products in natural sunlight and those expected from laboratory testing. Our results indicate that the labelled SPF, determined by in vivo assay using a UV solar simulator, overestimates the SPF that would be expected in natural sunlight to the extent that for products labelled SPF50+, it may not be possible to achieve a protection against sunlight of more than 25-fold...
August 16, 2017: Photochemical & Photobiological Sciences
S Lembo, G Caiazzo, N Balato, G Monfrecola, V Patra, P Wolf, A Balato
Polymorphic light eruption (PLE) is described as a delayed-type hypersensitivity reaction (DTHR) toward a de novo light-induced antigen, yet to be identified. In effect, the inflammatory pathways of PLE and allergic contact dermatitis (ACD) share common patterns in terms of the mediators involved from the innate and adaptive immune system participating in the DTHR. As we have previously highlighted the role of interleukin (IL)-1 family members in ACD, we hypothesised that the same mediators could have similar functions in PLE...
August 16, 2017: Photochemical & Photobiological Sciences
Pritam Torawane, Karunesh Keshav, Mukesh K Kumawat, Rohit Srivastava, Thangaraj Anand, Suban Sahoo, Amulrao Borse, Anil Kuwar
A new terephthaldehyde-based chemosensor 1 bearing an aminophenol recognition unit has been synthesized and applied to the fluorescent sensing of metal ions. Molecular system 1 acts as a highly selective and sensitive fluorescence turn-on sensor for Cu(2+). The sensing mechanism has been explored. It is proposed that Cu(2+) binds with the imine and hydroxyl moiety of 1 in 1 : 2 binding stoichiometry, thereby enhancing the fluorescence at 386 nm. The detection limit and association constant (Ka) of 1 with Cu(2+) were found to be 0...
August 11, 2017: Photochemical & Photobiological Sciences
Tim S Chung, Yang Xue, Alberto Carranza, Miguel A Garcia-Garibay
The stereospecific photochemistry of ten N-aryl-substituted cis- or trans-Δ(2)-1,2,3-triazolines to form the corresponding cis- or trans-aziridines was investigated both in solution and in the solid-state. We found that photochemical reactions in the solid state are more stereospecific than in solution for the 8 crystalline Δ(2)-1,2,3-triazolines. Additionally, triplet sensitization for some triazolines results in triplet biradicals, which provide the more thermodynamically favored trans-aziridine regardless of the starting triazoline stereochemistry...
August 10, 2017: Photochemical & Photobiological Sciences
Sara Corsico, Maurizio Fagnoni, Davide Ravelli
Tetrabutylammonium decatungstate has been exploited to photoinduce the trifluoromethylation of (hetero)aromatics and electron-poor olefins. The process made use of the cheap Langlois' reagent (CF3SO2Na) and occurred under sunlight irradiation in an acetonitrile/water mixture. The trifluoromethylation of (hetero)aromatics required the use of potassium persulfate as an additive and the mono- or bis-trifluoromethylated adducts were obtained, depending on the actual reaction conditions and the chosen substrate.
August 10, 2017: Photochemical & Photobiological Sciences
Yuta Shamoto, Mikio Yagi, Nozomi Oguchi-Fujiyama, Kazuyuki Miyazawa, Azusa Kikuchi
Hexyl diethylaminohydroxybenzoylbenzoate (DHHB, Uvinul A Plus) is a photostable UV-A absorber. The photophysical properties of DHHB have been studied by obtaining the transient absorption, total emission, phosphorescence and electron paramagnetic resonance spectra. DHHB exhibits an intense phosphorescence in a hydrogen-bonding solvent (e.g., ethanol) at 77 K, whereas it is weakly phosphorescent in a non-hydrogen-bonding solvent (e.g., 3-methylpentane). The triplet-triplet absorption and EPR spectra for the lowest excited triplet state of DHHB were observed in ethanol, while they were not observed in 3-methylpentane...
August 7, 2017: Photochemical & Photobiological Sciences
Yuichi Oba, Yoshiki Suzuki, Gabriel N R Martins, Rodrigo P Carvalho, Tatiana A Pereira, Hans E Waldenmaier, Shusei Kanie, Masashi Naito, Anderson G Oliveira, Felipe A Dörr, Ernani Pinto, Ilia V Yampolsky, Cassius V Stevani
We previously showed that luminous fungi share a common mechanism in bioluminescence, and identified hispidin as a luciferin precursor in Neonothopanus nambi mycelium. Here we showed the presence of hispidin as a bioluminescent active compound at 25-1000 pmol g(-1) in the fruiting bodies of Mycena chlorophos, Omphalotus japonicus, and Neonothopanus gardneri. These results suggest that luminous mushrooms contain hispidin as a luciferin precursor. We also found that non-luminous "young" fruiting bodies exhibited luminescence by hispidin treatment...
August 2, 2017: Photochemical & Photobiological Sciences
Natarajan Vijay, Gopal Balamurugan, Parthiban Venkatesan, Shu Pao Wu, Sivan Velmathi
A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu(2+) and Cr(3+) ions with significant changes in UV-Vis absorbance and fluorescence intensity. The results showed that Cr(3+) induced greater fluorescence enhancement whereas Cu(2+) ions bound strongly with the receptor by showing a strong absorption band at 554 nm but with weak fluorescence...
August 2, 2017: Photochemical & Photobiological Sciences
Mohamed E El-Khouly, Ahmed El-Refaey, Wonwoo Nam, Shunichi Fukuzumi, Özge Göktuğ, Mahmut Durmuş
A light harvesting subphthalocyanine-pyrene dyad has been synthesized and characterized by linking pyrene (Py) with subphthalocyanine (SubPc) at its axial position with the B-O bond through the para position of the benzene group. Upon photoexcitation at the pyrene unit of the dyad, an efficient electron transfer from the singlet-excited state of Py to SubPc was observed. The electron transfer features were also observed by exciting the SubPc entity, but with slower rates (∼10(8) s(-1)). From the electrochemical measurements, the negative driving forces for charge separation via both the singlet states of Py and SubPc in the polar solvents indicate that the electron transfer is thermodynamically feasible...
July 31, 2017: Photochemical & Photobiological Sciences
J L Fuentes, A García Forero, N Quintero Ruiz, C A Prada Medina, N Rey Castellanos, D A Franco Niño, D A Contreras García, Y Córdoba Campo, E E Stashenko
In this work, we investigated the usefulness of the SOS Chromotest for screening plant antigenotoxic agents against ultraviolet radiation (UV). Fifty Colombian plant extracts obtained by supercritical fluid (CO2) extraction, twelve plant extract constituents (apigenin, carvacrol, β-caryophyllene, 1,8-cineole, citral, p-cymene, geraniol, naringenin, pinocembrin, quercetin, squalene, and thymol) and five standard antioxidant and/or photoprotective agents (curcumin, epigallocatechin gallate, resveratrol, α-tocopherol, and Trolox®) were evaluated for their genotoxicity and antigenotoxicity against UV using the SOS Chromotest...
July 26, 2017: Photochemical & Photobiological Sciences
L Martinez-Fernandez, T Fahleson, P Norman, F Santoro, S Coriani, R Improta
The excited electronic states of 2-thiouracil, 4-thiouracil and 2,4-dithiouracil, the analogues of uracil where the carbonyl oxygens are substituted by sulphur atoms, have been investigated by computing the magnetic circular dichroism (MCD) and one-photon absorption (OPA) spectra at the time-dependent density functional theory level. Special attention has been paid to solvent effects, included by a mixed discrete/continuum model, and to determining how our results depend on the adopted DFT functional (CAM-B3LYP and B3LYP)...
July 26, 2017: Photochemical & Photobiological Sciences
Giuseppe Calogero, Ilaria Citro, Gaetano Di Marco, Stefano Caramori, Laura Casarin, Carlo Alberto Bignozzi, João Avó, A Jorge Parola, Fernando Pina
We present here a complete study on four synthetic environmentally friendly flavylium salts employed as sensitizers for dye-sensitized solar cells (DSSCs). The effect of several donor groups on the molecular structure of flavylium ions was investigated by combining electrochemical, spectroscopic and computational means. The computational investigation indicated that these molecules can interact strongly with the TiO2 surface by a single OH group of the dihydroxybenzene moiety, and can efficiently inject electrons into the TiO2 following the excitation of their lowest singlet states exhibiting charge transfer (CT) character...
July 21, 2017: Photochemical & Photobiological Sciences
Rym Boudjemaa, Romain Briandet, Marie-Pierre Fontaine-Aupart, Karine Steenkeste
Staphylococcus aureus is one of the most frequent pathogens responsible for biofilm-associated infections. Among current clinical antibiotics, very few enable long-term successful treatment. Thus, it becomes necessary to better understand antibiotic failures and successes in treating infections in order to master the use of proper antibiotic therapies. In this context, we took benefit from a set of fluorescence spectroscopy and imaging methods, with the support of conventional microbiological tools to better understand the vancomycin-rifampin combination (in)efficiency against S...
June 30, 2017: Photochemical & Photobiological Sciences
Jianlei Han, Fei Zhang, Jing You, Yonemura Hiroaki, Sunao Yamada, Toru Morifuji, Shirong Wang, Xianggao Li
Metallophthalocyanines (MPc-o-Cou, M = Fe, Co, Ni, and Cu) with fourth period metal ions have been successfully applied as a sensitizer coupled with rubrene (Rub) in photon upconversion based on triplet-triplet annihilation. An upconversion quantum yield (ϕPUC) of up to 4.82% was observed in the CoPc-o-Cou : Rub couple. The absorption and phosphorescence emission spectra showed that the Q bands and phosphorescence emission peaks were dramatically dependent on the number of d-electrons of the metal ions in MPc-o-Cou...
June 26, 2017: Photochemical & Photobiological Sciences
G Checcucci, B Storti, F Ghetti, G Signore, R Bizzarri
The step-up photophobic response of the heterotrich ciliate Blepharisma japonicum is mediated by a hypericinic pigment, blepharismin, which is not present in any of the known six families of photoreceptors, namely rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins, and BLUF proteins. Upon irradiation, native cells become light-adapted (blue) by converting blepharismin into the photochemically stable oxyblepharismin (OxyBP). So far, OxyBP has been investigated mainly from a photophysical point of view in vitro, either alone or complexed with proteins...
June 21, 2017: Photochemical & Photobiological Sciences
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August 9, 2017: Photochemical & Photobiological Sciences
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No abstract text is available yet for this article.
August 9, 2017: Photochemical & Photobiological Sciences
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No abstract text is available yet for this article.
August 9, 2017: Photochemical & Photobiological Sciences
J C Carmello, L N Dovigo, E G Mima, J H Jorge, C A de Souza Costa, V S Bagnato, A C Pavarina
Correction for 'In vivo evaluation of photodynamic inactivation using Photodithazine® against Candida albicans' by J. C. Carmello, et al., Photochem. Photobiol. Sci., 2015, 14, 1319-1328.
August 9, 2017: Photochemical & Photobiological Sciences
Fabiano S Santos, Elamparuthi Ramasamy, V Ramamurthy, Fabiano S Rodembusch
Correction for 'Photoinduced electron transfer across an organic molecular wall: octa acid encapsulated ESIPT dyes as electron donors' by Fabiano S. Santos et al., Photochem. Photobiol. Sci., 2017, 16, 840-844.
August 9, 2017: Photochemical & Photobiological Sciences
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