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Photochemical & Photobiological Sciences

Hiroya Sakurai, Takashi Maruyama, Tatsuo Arai
The photochemical properties of stilbene cored amphiphilic dendrimers (G0-G3) in THF and water were investigated. The solvation dynamics in water depended on the generation, while the behavior is almost the same in THF. Dendrimers G1 and G2 form molecular assemblies and undergo photodimerization reaction in addition to photoisomerization. G3 has enough TEG groups on the surface to cover the hydrophobic moiety within a single molecule. These dendrimers have free space around the core to undergo mutual isomerization even in water...
September 22, 2017: Photochemical & Photobiological Sciences
M E Rodríguez, C Catrinacio, A Ropolo, V A Rivarola, M I Vaccaro
Colon cancer is the third most frequent cancer and the fourth most common cause of cancer-related mortality worldwide and the standard therapy is surgical resection plus adjuvant chemotherapy. Photodynamic therapy (PDT) has been proposed as an adjuvant therapy because it can prevent the tumor recurrence after surgical excision in colon cancer patients. Hypoxia is a common feature in solid tumors and leads to chemo/radioresistance. Recently, it has been shown that in response to hypoxia, cells can induce HIF-1α-mediated autophagy to survive in this hostile microenvironment...
September 22, 2017: Photochemical & Photobiological Sciences
Marek Scholz, Roman Dědic, Jan Hála
Singlet oxygen is a highly reactive species which is involved in a number of processes, including photodynamic therapy of cancer. Its very weak near-infrared emission makes imaging of singlet oxygen in biological systems a long-term challenge. We address this challenge by introducing Singlet Oxygen Feedback Delayed Fluorescence (SOFDF) as a novel modality for semi-direct microscopic time-resolved wide-field imaging of singlet oxygen in biological systems. SOFDF has been investigated in individual fibroblast cells incubated with a well-known photosensitizer aluminium phthalocyanine tetrasulfonate...
September 22, 2017: Photochemical & Photobiological Sciences
Wei Zhu, Ying-Hua Gao, Chun-Hong Song, Zhi-Bin Lu, Tabbisa Namulinda, Yi-Ping Han, Yi-Jia Yan, Lai-Xing Wang, Zhi-Long Chen
Protoporphyrin IX (PpIX) is used as a photosensitizer in the photodynamic diagnosis (PDD) and photodynamic therapy (PDT) of cancer and is synthesized intracellularly from 5-aminolevulinic acid (5-ALA) precursors. Thirteen novel 5-ALA derivatives were designed and synthesized appropriately with tailored hydrophilicity and lipophilicity. The generation of PpIX was detected and their antitumor activity in vitro and in vivo was also investigated. It was shown that compounds 9b-c, 11b-c and 13a displayed a characteristic long wavelength absorption peak at 593 nm after 5 h incubation in mice fibrosarcoma S180 cells...
September 21, 2017: Photochemical & Photobiological Sciences
Tim Kohlmann, Robert Naumann, Christoph Kerzig, Martin Goez
The hydrated electron represents a "super-reductant" in water, providing 2.9 eV of reductive power, which suffices to decompose nonactivated aliphatic halides. We show that 3-amino-perylene in SDS micelles, when combined with the bioavailable ascorbate as an extramicellar sacrificial donor, sustainably produces hydrated electrons through photoredox catalysis with green light, from a metal-free system, and at near-physiological pH. Photoionization of the amine with a 532 nm laser yields an extremely long-lived radical cation as the by-product, and a subsequent reaction of the latter with the sacrificial donor across the micelle/water interface regenerates the catalyst...
September 19, 2017: Photochemical & Photobiological Sciences
Natalia Łukasik, Ewa Wagner-Wysiecka
The synthesis and complexing properties of p-aminoazobenzene-derived mono-, bis-, and trisamides were described. Ligands 3 and 4 bind anions, including fluorides, chlorides, bromides, acetates, benzoates, dihydrogen phosphates, hydrogen sulfates, and p-toluenesulfonates, in chloroform forming 1 : 1 complexes. The highest value of stability constant was evaluated for the 4-F(-) complex (log K = 5.63 ± 0.21). On the basis of (1)H NMR, and FTIR spectroscopy, the possible nature of the ligand-anion interactions was proposed...
September 8, 2017: Photochemical & Photobiological Sciences
Shan-Shan Zhou, Shou-Qing Liu
Cocatalysts are vital for improving photocatalytic activity. Incorporating nitrogen atoms on a graphene frame using an imidazole cycle resulted in a new N-doped graphene (denoted as ING). Cerium(iv) oxide (CeO2) nanoparticles were dispersed on ING sheets, producing an ING/CeO2 hybrid material. The ING/CeO2 hybrid material was characterized using X-ray diffraction, transmission electron microscopy, Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy and surface photovoltage spectroscopy...
September 8, 2017: Photochemical & Photobiological Sciences
Bhavesh Kumar Dadhich, Indrajit Kumar, Ravi Kant Choubey, Bhavya Bhushan, Amiya Priyam
Using a combination of a mild stabilizer and a mild reductant, sodium citrate and hydrazine hydrate, anisotropic silver nanocrystals (NCs) were synthesized with tunable plasmon peaks at 550 nm, 700 nm, 800 nm, 900 nm and 1010 nm (the samples are named Ag-550, Ag-700, Ag-800, Ag-900 and Ag-1010, respectively). TEM investigations revealed that Ag-550 NCs were pentagonal nanoplates while the other four samples were nanopyramids with a pentagonal base with the edge length varying between 15 and 30 nm. The non-linear optical (NLO) properties of these NCs were studied by the Z-scan technique using the CW He-Ne laser (632...
September 6, 2017: Photochemical & Photobiological Sciences
Trevor M Safko, Miklos Kertesz, Richard G Weiss
The photophysical properties of two new indole derivatives have been examined by steady-state and dynamic spectroscopic methods. The ground-state structures and conformations of 3-(1-indolyl)-N,N-dimethylpropan-1-ammonium chloride (InCl) and 3-(1-indolyl)-N,N,N-trimethylpropan-1-ammonium chloride (MeInCl) have been examined through density functional theory calculations. These calculations reveal a preference for a 'closed' conformation which places the cationic ammonium group in proximity to the π-electron cloud in low polarity environments...
September 6, 2017: Photochemical & Photobiological Sciences
Hao Ou-Yang, Thomas Shyr
Solar protection is an important public health issue because solar UV exposure can cause acute and chronic damage to the skin. Seeking shade is a convenient and commonly practiced sun avoidance measure. Shade works by physically shielding the skin from direct UV rays; however UV rays can also reach the skin from other angles. It is not clear how protective the widely-used shade structures like umbrellas and walls are under actual use conditions. In this study, a sky view model was applied to systematically assess the influence of different factors to umbrellas and walls, including the transmission of the shade materials, the reflectivity of the ground or the wall, diffused UV to total UV irradiance ratios, shade geometry, a person's positions and orientations in the shade...
August 29, 2017: Photochemical & Photobiological Sciences
Eugenia Reynoso, Ezequiel D Quiroga, Maximiliano L Agazzi, María B Ballatore, Sonia G Bertolotti, Edgardo N Durantini
The photodynamic inactivation mediated by 1,3,5,7-tetramethyl-8-[4-(N,N,N-trimethylamino)phenyl]-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene 3 and 8-[4-(3-(N,N,N-trimethylamino)propoxy)phenyl]-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene 4 was investigated on Staphylococcus aureus, Escherichia coli and Candida albicans. In vitro experiments indicated that BODIPYs 3 and 4 were rapidly bound to microbial cells at short incubation periods. Also, fluorescence microscopy images showed green emission of BODIPYs bound to microbial cells...
August 24, 2017: 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
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
(no author information available yet)
No abstract text is available yet for this article.
September 13, 2017: Photochemical & Photobiological Sciences
(no author information available yet)
No abstract text is available yet for this article.
September 13, 2017: Photochemical & Photobiological Sciences
(no author information available yet)
No abstract text is available yet for this article.
September 13, 2017: Photochemical & Photobiological Sciences
Susan Callaghan, Mikhail A Filatov, Elisabeth Sitte, Huguette Savoie, Ross W Boyle, Keith J Flanagan, Mathias O Senge
A new type of porphyrin photosensitizer capable of generating singlet oxygen upon irradiation, storing it through binding to pyridone subunits, followed by slow release at 20-40 °C, is reported. The timescale of singlet oxygen release can be varied depending on the pyridone group substitution pattern, forming endoperoxides of different stabilities. Modified tetra- and octa-substituted pyridone-porphyrins showed solubility in water, allowing for straightforward delivery into cells. The effect of delayed singlet oxygen formation due to endoperoxide decomposition was demonstrated on cancer cells in vitro...
September 13, 2017: Photochemical & Photobiological Sciences
Alois W Schmalwieser, Julian Gröbner, Mario Blumthaler, Barbara Klotz, Hugo De Backer, David Bolsée, Rolf Werner, Davor Tomsic, Ladislav Metelka, Paul Eriksen, Nis Jepsen, Margit Aun, Anu Heikkilä, Thierry Duprat, Henner Sandmann, Tilman Weiss, Alkis Bais, Zoltan Toth, Anna-Maria Siani, Luisa Vaccaro, Henri Diémoz, Daniele Grifoni, Gaetano Zipoli, Giuseppe Lorenzetto, Boyan H Petkov, Alcide Giorgio di Sarra, Francis Massen, Charles Yousif, Alexandr A Aculinin, Peter den Outer, Tove Svendby, Arne Dahlback, Bjørn Johnsen, Julita Biszczuk-Jakubowska, Janusz Krzyscin, Diamantino Henriques, Natalia Chubarova, Predrag Kolarž, Zoran Mijatovic, Drago Groselj, Anna Pribullova, Juan Ramon Moreta Gonzales, Julia Bilbao, José Manuel Vilaplana Guerrero, Antonio Serrano, Sandra Andersson, Laurent Vuilleumier, Ann Webb, John O'Hagan
The UV Index was established more than 20 years ago as a tool for sun protection and health care. Shortly after its introduction, UV Index monitoring started in several countries either by newly acquired instruments or by converting measurements from existing instruments into the UV Index. The number of stations and networks has increased over the years. Currently, 160 stations in 25 European countries deliver online values to the public via the Internet. In this paper an overview of these UV Index monitoring sites in Europe is given...
September 13, 2017: Photochemical & Photobiological Sciences
N A Richarz, J Aguilera, G Castillo, M J Fuente, C Ferrándiz, J M Carrascosa
We present the case of a phototoxic skin reaction due to the regular intake of a combined oral contraceptive (levonorgestrel/ethinylestradiol). Upon spectrophotometer testing, we demonstrated high absorption in the UV-B region of the solar spectrum of the combined product (Ovoplex®), especially for the estrogen compound (ethinylestradiol).
September 13, 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...
September 13, 2017: Photochemical & Photobiological Sciences
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