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Photochemistry and Photobiology

Valery F Traven, Dmitriy A Cheptsov, Maria V Bulanova, Natalya P Solovjova, Tatyana A Chibisova, Sergei M Dolotov, Ivan V Ivanov
New (1,5-diaryl-3-pyrazolinyl)coumarins have been synthesized. In opposite to (1,5-diaryl-3-pyrazolinyl)-4-hydroxycoumarins these compounds are not able to keto-enol tautomeric transformations with changes of the solvent. (1,5-Diaryl-3-pyrazolinyl)coumarins provide dehydrogenation reaction under irradiation in the presence of perchloroalkanes and manifest themselves as effective photogenerators of acidity. Several aspects of photodehydrogenation mechanism have been studied. Oxygen is shown not be involved in the reaction...
March 11, 2018: Photochemistry and Photobiology
Gang Dai, Xiong Geng, Luomeng Chao, Jun Tamogami, Takashi Kikukawa, Makoto Demura, Naoki Kamo, Tatsuo Iwasa
Aspartic acid 103 (D103) of sensory rhodopsin II from Halobacterium salinarum (HsSRII, or also called phoborhodopsin) corresponds to D115 of bacteriorhodopsin (BR). This amino acid residue is functionally important in BR. The present work reveals that a substitution of D103 with asparagine (D103N) or glutamic acid (D103E) can cause large changes in HsSRII photocycle. These changes include (1) shortened lifetime of the M intermediate in the following order: the wild-type > D103N > D103E; (2) altered decay pathway of a 13-cis O-like species...
March 7, 2018: Photochemistry and Photobiology
Fiona O'Sullivan, Jos van Geffen, Michiel van Weele, Lina Zgaga
Vitamin D has been shown to be beneficial at reducing the risk of cancer, however studies examining oesophageal and gastric cancer have been scarce and findings inconsistent. The UK Biobank cohort was used for this nested case-control study (N=3,732). Primary, incident oesophageal and gastric cancer cases diagnosed after recruitment were identified via linkage to National Cancer Registries. Tropospheric emissions monitoring internet service database was used to calculate ambient annual UVB dose (D-UVB). Conditional logistic regression was used to investigate the relationship between annual ambient D-UVB and risk of oesophageal and gastric cancer and odds ratios (OR) are reported...
February 27, 2018: Photochemistry and Photobiology
Conor L Evans
The natural pigments known as melanins are thought to play a role in the etiology and progression of melanoma, but many of their roles are currently not well understood. While quantification of melanins have, up until now, have been performed in bulk, new imaging technologies have unlocked the means to visualize and quantify melanins. The nonlinear imaging methods known as Pump-Probe, Coherent Raman, and Sum Frequency Absorption microscopies, provide subcellular resolution imaging of melanins, enabling label-free, longitudinal quantification of both eumelanin and pheomelanin in situ and in vivo...
February 27, 2018: Photochemistry and Photobiology
Xuan Liao, Sheng-Hong Li, Guang-Hui Xie, Shan Xie, Li-Ling Xiao, Jian-Xing Song, Hong-Wei Liu
The present study was conducted to explore the therapeutic potential of human adipose-derived stem cells (ADSCs) irradiated with a low level laser (LLL). Cultured ADSCs were treated with 650-nm GaAlAs laser irradiation at 2, 4, and 8 J/cm2 . Cell proliferation was quantified by MTT assays, cytokine secretion was determined by enzyme-linked immunosorbent assays, and adipogenic differentiation was examined by oil red O staining. Additionally, the expression profiles of putative ADSC surface markers were analyzed by quantitative real-time PCR...
February 19, 2018: Photochemistry and Photobiology
Reza Fekrazad, Arash Sarrafzadeh, Katayoun Am Kalhori, Imran Khan, Praveen R Arany, Alessio Giubellino
Diabetic wounds are a major cause of morbidity among patients with poorly controlled blood glucose levels. Conventional empirical wound care strategies have shown limited efficacy and there is an urgent need to develop novel therapeutic strategies. Photobiomodulation treatments have shown a positive therapeutic effects in several cell culture and animal models. In this study, we examined wound healing in diabetic rats following treatments with two laser wavelengths, namely red (660nm) and infrared (808nm) individually and in combination as compared to routine wound dressings...
February 19, 2018: Photochemistry and Photobiology
Laxiang Yang, Mengkai Li, Wentao Li, James R Bolton, Zhimin Qiang
A mini-fluidic vacuum ultraviolet/ultraviolet (VUV/UV) photoreaction system (MVPS) was developed in our previous study. Based on the MVPS, a green method to determine VUV fluence rate has been developed using the production rate of H2 O2 when water is exposed to 185 nm VUV. The H2 O2 production followed pseudo-zero-order reaction kinetics well over the first 10 min of VUV/UV exposure. This new method was well calibrated with a standard cis-cyclooctene cis-trans photoisomerization actinometer as recommended by the International Union of Pure and Applied Chemistry...
February 19, 2018: Photochemistry and Photobiology
Nancy Pizarro, Gaspar Prado, Marianela Saldías, Catalina Sandoval-Altamirano, Andrés Vega
The reaction of 2,5-dibromopyrazine with N-Lithium pyrazolate in a 1:2 ratio leads to a mixture of 2-bromo-5-(1H-pyrazol-1-yl)pyrazine (I) and 2,5-di(1H-pyrazol-1-yl)pyrazine (II). The structures of I and II are highly planar. Two absorption bands can be observed for the compounds in the UV-Vis region, having ε in the order of 10 4 M -1 cm -1 . TD-DFT computed results support the nature of the lower energy absorptions as π pyrazine →π* pyrazine transitions, including an additional intraligand charge transfer transition for I (π pyrazol →π* pyrazine )...
February 15, 2018: Photochemistry and Photobiology
Abel A Silva, Ana L C Yamamoto, Marcelo P Corrêa
The maintenance of ground-based instruments to measure the incidence of ultraviolet radiation (UVR) from the Sun demands strict and well-developed procedures. A piece of equipment can be out of service for a couple of weeks or months for calibration, repair, or even the improvement of the facilities where it has been set up. However, the replacement of an instrument in such circumstances can be logistically and financially prohibitive. On the other hand, the lack of data can jeopardize a long-term experiment...
February 15, 2018: Photochemistry and Photobiology
Wei Gao, Yu-Shuai Wang, Zheng-Yi Qu, Eunson Hwang, Hien T T Ngo, Ying-Ping Wang, Jahyun Bae, Tae-Hoo Yi
UV radiation is the primary cause of skin photoaging, which results in an increase in matrix metalloproteinases and degradation of collagen. Developing new natural antioxidant as photoprotective agents have become a popular area of research. Orobanche cernua Loefling is a parasitic plant that is rich in phenylethanoid glycosides (PhGs). This study investigated the photoprotective effects of the ethanolic extract of Orobanche cernua Loefling (OC) and its principal component acteoside on UVB-induced photoaging as well as their underlying molecular mechanisms in normal human dermal fibroblasts (NHDFs)...
February 15, 2018: Photochemistry and Photobiology
Firozeh Torki, Hossein Faghihian
This research was aimed to prepare a magnetically photocatalyst enabling to degrade pharmaceutical wastewater and detoxification of pollutant such as naproxen, by visible light irradiation. The nano-sized NiS and NiO photocatalysts exhibit higher reactivity than their micro-sized counterparts but separation of the used photocatalyst from the degradation solution is hard and imperfect. To remove this difficulty, magnetic polypyrrole core-shell (Fe3O4@PPY) was synthesized and employed as catalyst support. The magnetization property of the synthesized photocatalysts measured by VSM technique indicated that the photocatalysts were sufficiently magnetized to be readily separated from degradation solution by use of external magnetic field...
February 14, 2018: Photochemistry and Photobiology
Lars Olof Björn
Photoenzymes are enzymes that catalyze photochemical reactions. For a long time it was believed that only two types of photoenzymes exist: Light-dependent NADPH:protochlorophyllide oxidoreductase and photolyase. However, other photoenzymes have now been discovered, most recently fatty acid photodecarboxylase. This article is protected by copyright. All rights reserved.
February 13, 2018: Photochemistry and Photobiology
Sunil Kumar, A D Verma, S Pal, I Sinha
Curcumin functionalized Ag/Ag2O (c-Ag/Ag2O) nanocomposites with varying proportions of curcumin and Ag/Ag2O were prepared by a simple one pot green synthesis protocol in aqueous medium. The plasmonic band undergoes slight red shift, broadening and decrease in intensity with increase in proportion of Ag2O formed. These composite nanoparticles were found to be efficient visible light photocatalysts for aerobic oxidation of methyl orange and rhodamine B (RhB). Functionalization by curcumin significantly enhanced the photocatalytic activity with good reusability...
February 13, 2018: Photochemistry and Photobiology
Rong Liu, Yonggang Zhang
Photoelectrocatalytic (PEC) system greatly improves the migration of photo-excited charges, retards the fast recombination of electron-hole and increases the lifetime of photo-generated holes. In this paper, we constructed a novel PEC system to degrade Berberine chloride form (BCF). XRD patterns indicated ageing time was an important condition for the crystal type of TiO 2 and the best proportion of anatase/rutile was 80/20. The band gap energy of the TiO 2 was 3.01 eV. We demonstrated that a synergistic effect existed between photocatalysis (PC) and electrocatalysis (EC)...
February 13, 2018: Photochemistry and Photobiology
Niluksha Walalawela, Mariana Vignoni, María Noel Urrutia, Sarah J Belh, Edyta M Greer, Andrés H Thomas, Alexander Greer
Alkylation patterns and excited state properties of pterins were examined both experimentally and theoretically. 2D NMR spectroscopy was used to characterize the pterin derivatives, revealing undoubtedly that the decyl chains were coupled to either the O4 or N3 sites on the pterin. At a temperature of 70 °C the pterin alkylation regioselectively favored the O4 over the N3. The O4 was also favored when using solvents in which the reactants had increased solubility, namely N,N-dimethylformamide and N,N-dimethylacetamide, rather than solvents in which the reactants had very low solubility (tetrahydrofuran and dichloromethane)...
February 13, 2018: Photochemistry and Photobiology
Rahul Jadia, Janel Kydd, Prakash Rai
Triple Negative Breast Cancer (TNBC) has the worst prognosis amongst all sub-types of breast cancer. Currently no targeted treatment has been approved for TNBC. The goal of this study was to design a remotely triggered, targeted therapy for TNBC using polymeric nanoparticles and light. Active targeting of TNBC was achieved by conjugating the nanoparticles to a peptide (hTf) that binds to the transferrin receptor, which is overexpressed in TNBC. Photodynamic Therapy (PDT) was explored for TNBC treatment by remotely triggering benzoporphyrin derivative monoacid (BPD), a photosensitizer, using near infrared light...
February 10, 2018: Photochemistry and Photobiology
Anne E Cust, Georgina L Fenton, Amelia K Smit, David Espinoza, Suzanne Dobbinson, Alison Brodie, Huong Tran Cam Dang, Michael G Kimlin
Self-reported sun exposure is commonly measured using questionnaires or diaries, but there are limited data on their validity, particularly for population subgroups. This research aimed to compare self-reported sun exposure, measured as 1) habitual time outdoors over the past month on weekends and weekdays, and 2) a four-day diary measure, against objective measurement of personal ultraviolet radiation using polysulfone film dosimeters. From November 2015 to January 2016, 94 people (22-69 years and living in New South Wales, Australia) completed a questionnaire, 4-day diary and 4-day dosimeter measures of overall, weekday and weekend sun exposure...
February 8, 2018: Photochemistry and Photobiology
Lu Li, Eunson Hwang, Hien T T Ngo, Pei Lin, Wei Gao, Ying Liu, Tae-Hoo Yi
Cherry blossoms have attracted attention as an ingredient with potential for use in skincare products. However, no skin photoaging-related research has been performed with this plant. In the present study, cherry blossom extract (CBE) at 1, 10, and 100 μg/mL was investigated for its skin anti-photoaging effects in UVB-irradiated normal human dermal fibroblasts (NHDF) cells in vitro. Our results showed that CBE markedly increased type I procollagen during UVB exposure via two pathways. Firstly, transcription activator protein-1 expression and MAP kinases were downregulated, consequently reducing the production of matrix metalloproteinase (MMP)-1 and MMP-3...
February 8, 2018: Photochemistry and Photobiology
Wongnapa Nakyai, Marion Tissot, Philippe Humbert, François Grandmottet, Jarupa Viyoch, Céline Viennet
Skin photoaging is caused by cumulative UVA exposure that leads to dermal matrix alterations associated with impaired fibroblast functions. In this study, we evaluated the effects of repeated UVA irradiation on mechanically stressed fibroblasts which were embedded in 3D tense collagen matrix. By comparison to 2D monolayer culture, we investigated the expressions of alpha smooth muscle actin (α-SMA) cytoskeleton and α2 subunit of integrin receptors, as well as the collagen metabolism, focusing to MMP-1 and collagen type I expressions...
February 8, 2018: Photochemistry and Photobiology
Bharath Velaga, Pradeep P Shanbogh, Diptikanta Swain, Chandrabhas Narayana, Nalini G Sundaram
SnO2 -Ta2 O5 nanocomposite was synthesised by a facile co-precipitation method and further calcined to obtain crystalline powder. Phase formation, morphology, bandgap and photo-catalytic properties were analysed using powder X-ray diffraction, Scanning electron microscopy, UV-Vis diffused reflectance spectroscopy, BET surface area and Raman spectroscopy respectively. Effect of calcination temperature on the crystallinity of the composite was studied. The as prepared samples of SnO2 , Ta2 O5 and SnO2 -10wt%Ta2 O5 composite as well as the calcined composite sample were tested for photocatalytic activity for methylene blue dye degradation under visible light...
February 8, 2018: Photochemistry and Photobiology
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