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Photochemical & Photobiological Sciences

Tae-Rin Kwon, Jong Hwan Kim, Ji-Yeon Hong, Joon Seok, Jae Min Kim, Dong-Ho Bak, Mi-Ji Choi, Seok Kyun Mun, Chan Woong Kim, Beom Joon Kim
Ultraviolet (UV) light produces an immunomodulatory effect on the skin and is widely used for the treatment of chronic inflammatory skin diseases. UV light emitting diodes (UV-LEDs) are a new and promising source of UV radiation. However, their mechanism of action remains largely unknown. In this study, we tested the safety and effectiveness of UV-LED irradiation for the treatment of atopic dermatitis (AD) in an NC/Nga mouse model. Mice were divided into seven groups of eight mice each. Application of Dermatophagoides farinae (Df) extract ointment for four weeks induced AD-like skin lesions...
July 18, 2018: Photochemical & Photobiological Sciences
Robyn M Lucas, Rachel E Neale, Sasha Madronich, Richard L McKenzie
Correction for 'Are current guidelines for sun protection optimal for health? Exploring the evidence' by Robyn M. Lucas et al., Photochem. Photobiol. Sci., 2018, DOI: 10.1039/c7pp00374a.
July 17, 2018: Photochemical & Photobiological Sciences
Hajime Maeda, Hiroshi Takayama, Masahito Segi
The irradiation of aqueous acetonitrile solutions, containing electron deficient alkenes, dienes and active methylene compounds along with sodium or cesium carbonate and catalytic amounts of phenanthrene or pyrene, gives rise to the formation of novel three-component coupling products and diene dimers. Cinnamonitrile and benzylidenemalononitrile and its derivatives serve as electron-acceptors; 2,5-dimethyl-2,4-hexadiene and malononitrile anion serve as electron donors in this process. Based on the results of UV-vis absorption spectroscopy and the calculated ΔG values for single electron transfer (SET), mechanisms are proposed for the coupling reaction involving photoinduced electron transfer (PET) between the electron deficient alkenes and dienes or malononitrile anion via direct excitation of electron deficient alkenes or redox photosensitization using phenanthrene or pyrene serving as a photosensitizer...
July 12, 2018: Photochemical & Photobiological Sciences
Matthieu Sala, Dassia Egorova
Excited-state dynamics of pentafluorobenzene is studied in detail for a quartic vibronic coupling model including the six b1 vibrational modes of the molecule and the two lowest excited electronic states. The study analyzes the influence of the large-amplitude out-of-plane vibrational motion on the electronic dynamics and extends to the simulation of the emerging time-resolved photoelectron spectra. The mapping of coherent non-separable electron-nuclear motion into oscillatory photoelectron signals is discussed...
July 12, 2018: Photochemical & Photobiological Sciences
Xianqiang Xiong, Xiao Zhang, Shengwei Liu, Jianjun Zhao, Yiming Xu
UV irradiation of Au/TiO2 photocatalysts in the presence of borate and phosphate anions can produce H2O2 at a millimolar level in alkaline water solution. The positive effect of the anions is ascribed to the anion-mediated hole transfer from Au/TiO2 to an electron donor which thus accelerates the two-electron reduction of O2 to H2O2.
July 12, 2018: Photochemical & Photobiological Sciences
L Aranzazú Díaz-Ramos, Andrew O'Hara, Selvaraju Kanagarajan, Daniel Farkas, Åke Strid, Gareth I Jenkins
The photoreceptor UV RESISTANCE LOCUS 8 (UVR8) activates photomorphogenic responses when plants are exposed to ultraviolet-B (UV-B) light. However, whereas the absorption spectrum of UVR8 peaks at 280 nm, action spectra for several photomorphogenic UV-B responses show maximal photon effectiveness at 290-300 nm. To investigate this apparent discrepancy we measured the effectiveness of UV wavelengths in initiating two responses in Arabidopsis: photoconversion of homodimeric UVR8 into the monomeric form, which is active in signaling, and accumulation of transcripts of the ELONGATED HYPOCOTYL 5 (HY5) transcription factor, which has a key role in UVR8-mediated responses...
July 11, 2018: Photochemical & Photobiological Sciences
Mohamed E El-Khouly, Ahmed El-Refaey, Shaban Y Shaban, Morad M El-Hendawy
Electronic interactions between the cationic N,N'-bis(2(trimethylammonium iodide) ethylene)perylene-3,4,9,10-tetracarboxyldiimide (TAIPDI) with two electron donors, namely, pyrene (Py) and 1-pyrenesulfonic acid sodium salt (PySA), have been investigated. The spectroscopic studies showed the formation of the supramolecular conjugate between TAIPDI and PySA via ionic interaction, but not with Py. Density functional theory (DFT) combined with a natural energy decomposition analysis (NEDA) technique showed an S-like structure of the supramolecular conjugate TAIPDI-PySA via an ionic interaction...
July 11, 2018: Photochemical & Photobiological Sciences
Sasha Madronich, Lars Olof Björn, Richard L McKenzie
Many microorganisms are alive while suspended in the atmosphere, and some seem to be metabolically active during their time there. One of the most important factors threatening their life and activity is solar ultraviolet (UV) radiation. Quantitative understanding of the spatial and temporal survival patterns in the atmosphere, and of the ultimate deposition of microbes to the surface, is limited by a number factors some of which are discussed here. These include consideration of appropriate spectral sensitivity functions for biological damage (e...
July 6, 2018: Photochemical & Photobiological Sciences
Yusuke Kuramochi, Sho Hashimoto, Yuki Kawakami, Motoko S Asano, Akiharu Satake
A macroring composed of three Cu(ii) porphyrins (CuP) and three slipped-cofacial Zn(ii) porphyrin (ZnP2) dimers exhibited near-IR emission from the CuP part. The emission lifetime of the macroring (15 μs) was 500 times longer compared to that of a Cu porphyrin monomer (e.g., Cu(ii)TPP; TPP = meso-tetraphenylporphyrin). The observed emission is ascribed to emission via the reservoir mechanism from the trip-doublet (2T1) state in CuP thermally activated from the T1 state of ZnP2, which is located ca. 1030 cm-1 below the 2T1 state of CuP...
June 28, 2018: Photochemical & Photobiological Sciences
Canan Baslak, Ahmed Nuri Kursunlu
A novel naphthalene-Bodipy dye (N-Bodipy) was designed, prepared and characterized. N-Bodipy showed a selective and sensitive recognition toward Cu(ii) ions as a fluorescent antenna group in acetonitrile/water over other metal cations. The complexation between Cu(ii) ions and N-Bodipy gave a specific color change as well as caused fluorescence quenching under long-wavelength light (365 nm). The remarkable quenching effect in fluorescence intensity centered at 538 nm was only observed in the presence of copper(ii) ions...
June 27, 2018: Photochemical & Photobiological Sciences
Peipei Yan, Di Li, Xinguo Ma, Juanqin Xue, Yujie Zhang, Manbo Liu
Bi2WO6 nanosheets were synthesized by a hydrothermal method with H2WO4 for the first time. The band structure of Bi2WO6 was investigated on the basis of density functional theory calculations. Bi2WO6 photocatalysts showed photocatalytic activity for the degradation of methylene blue under visible light irradiation. Kinetic studies using radical scavenger technologies suggested that holes were the dominant photo-oxidants. After hybridization with C3N4, the photocatalytic activity of Bi2WO6 was obviously enhanced...
June 26, 2018: Photochemical & Photobiological Sciences
L Larue, A Ben Mihoub, Z Youssef, L Colombeau, S Acherar, J C André, P Arnoux, F Baros, M Vermandel, C Frochot
Photodynamic therapy is a therapeutic option to treat cancer and other diseases. PDT is used every day in dermatology, and recent developments in the treatment of glioblastoma, mesothelioma or prostate have demonstrated the efficacy of this modality. In order to improve the efficacy of PDT, different strategies are under development, such as the use of targeted PS or nanoparticles to improve selectivity and the design of light devices to better monitor the light dose. Due to the low penetration of light into tissue, another way to improve the efficacy of PDT to treat deep tumors is the use of upconversion NPs or bi-photon absorption compounds...
June 25, 2018: Photochemical & Photobiological Sciences
Xiaoxu Li, Ece Erturk, Xin Chen, Shiv Kumar, Cheng Guo, Steffen Jockusch, James J Russo, Timothy H Bestor, Jingyue Ju
Epigenetic information is encoded in the mammalian genome in the form of cytosines methylated at the 5 position. Cytosine methylation has multiple biological effects, but our understanding of these effects has lagged because extant methods for mapping methylation sites genome-wide have severe shortcomings. For instance, the gold standard bisulfite sequencing approach suffers from the use of harsh reaction conditions resulting in DNA cleavage and incomplete conversion of unmethylated cytosine to uracil. We report here on a new photochemical method in which a DNA (cytosine-5)-methyltransferase can be used to covalently attach reactive functionalities which upon irradiation at ∼350 nm initiate photoinduced intramolecular reactions that convert modified C to T analogues...
June 21, 2018: Photochemical & Photobiological Sciences
Daniel R Garźon-Chavez, Emmanuelle Quentin, Simone L Harrison, Alfio V Parisi, Harry J Butler, Nathan J Downs
Tropical Ecuador presents a unique climate in which we study the relationship between the ambient levels of solar ultraviolet radiation and eye disease in the absence of a latitudinal gradient. The national distribution of surface ultraviolet, taking into account MODIS and OMI satellite observation of aerosol, ozone, surface albedo, local elevation and cloud fractions measured during 2011, was compared with the national pterygium (WHO ICD H11) and senile cataract (WHO ICD H25) incidence projected from the 2010 National Institute of Statistics and Census (Ecuador)...
June 21, 2018: Photochemical & Photobiological Sciences
M Garmyn, A R Young, S A Miller
Humans have been exposed to solar UV radiation since their appearance on Earth and evolution has enabled most individuals to adapt to this exposure, to some degree. UV radiation produces several deleterious effects in human skin and light-skinned individuals are at greatest risk for both acute and long-term negative effects such as DNA damage, sunburn, immune suppression and skin cancer. The benefits of photoadaptation, which leads to a decreased response after acclimatization, are that humans who have skin that is capable of photoadaptation can work and play in the sun with reduced fear of painful sunburn...
June 21, 2018: Photochemical & Photobiological Sciences
Tripti Mandal, Anowar Hossain, Anamika Dhara, Abdulla Al Masum, Saugata Konar, Saikat Kumar Manna, Saikat Kumar Seth, Sudipta Pathak, Subrata Mukhopadhyay
A terpyridine based compound L1 was designed and synthesized as an "off-on" chemosensor for the detection of Zn2+. Chemosensor L1 showed excellent selectivity and sensitivity toward Zn2+ by exhibiting a large fluorescence enhancement (∼51-fold) at 370 nm whereas other competitive metal ions did not show any noticeable change in the emission spectra of chemosensor L1. The chemosensor (L1) was shown to detect Zn2+ ions down to 9.76 μM at pH 7.4. However, chemosensor L1 binds Zn2+ in a 1 : 2 ratio (receptor : metal) with an association constant of 1...
June 20, 2018: Photochemical & Photobiological Sciences
Luiz Philippe da Silva Sergio, Andrezza Maria Côrtes Thomé, Larissa Alexsandra da Silva Neto Trajano, Andre Luiz Mencalha, Adenilson de Souza da Fonseca, Flávia de Paoli
Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are defined as pulmonary inflammation that could occur from sepsis and lead to pulmonary permeability and alveolar edema making them life-threatening diseases. Photobiomodulation (PBM) properties have been widely described in the literature in several inflammatory diseases; although the mechanisms of action are not always clear, this could be a possible treatment for ARDS/ALI. Thus, the aim of this study was to evaluate the mRNA levels from caspase-3 and BCL-2 genes and DNA fragmentation in lung tissue from Wistar rats affected by ALI and subjected to photobiomodulation by exposure to a low power infrared laser (808 nm; 100 mW; 3...
June 20, 2018: Photochemical & Photobiological Sciences
Wolf-Ulrich Palm
Dark and photolysis reactions in solution were investigated for 9-acridinecarboxaldehyde (ACL). ACL reacts in the dark at T = 20 °C and pH = 7.0 in an air saturated solution to the main product 9-acridinecarboxylic acid (ACA) and to the minor product 9-acridinemethanol (ACM) with a lifetime of τ = 4.3 days. The dissociation constant of the base ACLH+ was determined to be pKa ± σ = 4.38 ± 0.04. The photolysis of ACL was investigated using a polychromatic Xe-light source. The quantum yield in aqueous solution at T = 20 °C in a concentration range of c0(ACL) = 0...
June 19, 2018: Photochemical & Photobiological Sciences
E Erdmann, A Villinger, B König, W W Seidel
We report the synthesis and the spectroscopic and electrochemical properties of six mononuclear iridium(iii) and ruthenium(ii) complexes bearing S,S'-extended phenanthroline ligands. Starting from 5,6-dibromide-1,10-phenanthroline, the dithiine derivatives N,N'-1,10-phenanthrolinedithiino[2,3-b]quinoxaline and N,N'-1,10-phenanthrolinedithiino[2,3-b]benzene were prepared by primary N,N'-complexation of the dibromo derivative and subsequent nucleophilic substitution at the complex. The photoluminescence of the phenanthroline-dithiine containing complexes shows distinctively increased lifetimes for all Ir(iii) and Ru(ii) complexes...
June 19, 2018: Photochemical & Photobiological Sciences
Anand S Dixit, Sanborlang Byrsat
Day length has been shown to be a major source of temporal information regulating seasonal reproduction in the Eurasian tree sparrow (Passer montanus). The present study aims to investigate the photoperiodic expression of gonadotropin-releasing hormone-I (GnRH-I), and how it mediates seasonal reproduction in male tree sparrows. In different experiments, we studied photoperiod-induced changes in GnRH-I expressing neurons in the hypothalamic preoptic area (POA), together with changes in testicular size under both natural and artificial photoperiodic conditions...
June 18, 2018: Photochemical & Photobiological Sciences
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