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  Subjects -> CHEMISTRY (Total: 767 journals)
    - ANALYTICAL CHEMISTRY (45 journals)
    - CHEMISTRY (532 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (24 journals)
    - INORGANIC CHEMISTRY (40 journals)
    - ORGANIC CHEMISTRY (40 journals)
    - PHYSICAL CHEMISTRY (64 journals)

CHEMISTRY (532 journals)            First | 1 2 3 4 5 6 | Last

Journal of Immunoassay and Immunochemistry     Hybrid Journal   (Followers: 3)
Journal of Inclusion Phenomena and Macrocyclic Chemistry     Hybrid Journal   (Followers: 2)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 2)
Journal of Labelled Compounds and Radiopharmaceuticals     Hybrid Journal   (Followers: 1)
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry     Hybrid Journal   (Followers: 4)
Journal of Mass Spectrometry     Hybrid Journal   (Followers: 20)
Journal of Materials Chemistry A : Materials for Energy and Sustainability     Full-text available via subscription   (Followers: 23)
Journal of Materials Chemistry B : Materials for Biology and Medicine     Full-text available via subscription   (Followers: 5)
Journal of Materials Chemistry C : Materials for Optical, Magnetic and Electronic Devices     Full-text available via subscription   (Followers: 6)
Journal of Materials Research     Full-text available via subscription   (Followers: 9)
Journal of Mathematical Chemistry     Hybrid Journal   (Followers: 4)
Journal of Medicinal Chemistry     Full-text available via subscription   (Followers: 154)
Journal of Membrane Science     Hybrid Journal   (Followers: 9)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 2)
Journal of Molecular Graphics and Modelling     Hybrid Journal   (Followers: 3)
Journal of Molecular Liquids     Hybrid Journal   (Followers: 3)
Journal of Molecular Modeling     Hybrid Journal   (Followers: 3)
Journal of Molecular Recognition     Hybrid Journal   (Followers: 1)
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 6)
Journal of Molecular Structure     Hybrid Journal   (Followers: 3)
Journal of Nanoparticles     Open Access  
Journal of Nanostructure in Chemistry     Open Access   (Followers: 5)
Journal of Natural Gas Chemistry     Full-text available via subscription   (Followers: 2)
Journal of Nepal Chemical Society     Open Access  
Journal of Nucleic Acids Investigation     Open Access   (Followers: 2)
Journal of Ocean University of China (English Edition)     Hybrid Journal   (Followers: 2)
Journal of Organometallic Chemistry     Hybrid Journal   (Followers: 12)
Journal of Photochemistry and Photobiology A: Chemistry     Hybrid Journal   (Followers: 4)
Journal of Photochemistry and Photobiology C: Photochemistry Reviews     Full-text available via subscription   (Followers: 4)
Journal of Polymer Science Part A: Polymer Chemistry     Hybrid Journal   (Followers: 158)
Journal of Polymers     Open Access   (Followers: 1)
Journal of Porphyrins and Phthalocyanines     Hybrid Journal   (Followers: 2)
Journal of Pure and Applied Chemistry Research     Open Access  
Journal of Raman Spectroscopy     Hybrid Journal   (Followers: 9)
Journal of Saudi Chemical Society     Open Access  
Journal of Solid State Chemistry     Hybrid Journal   (Followers: 13)
Journal of Solution Chemistry     Hybrid Journal  
Journal of Structural Chemistry     Hybrid Journal  
Journal of Sulfur Chemistry     Hybrid Journal   (Followers: 2)
Journal of Superhard Materials     Hybrid Journal   (Followers: 1)
Journal of Surfactants and Detergents     Hybrid Journal   (Followers: 5)
Journal of Systems Chemistry     Open Access   (Followers: 1)
Journal of Taibah University for Science     Open Access  
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 238)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 16)
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 1)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Chilean Chemical Society     Open Access   (Followers: 2)
Journal of the Iranian Chemical Society     Hybrid Journal   (Followers: 1)
Journal of the Korean Society for Applied Biological Chemistry     Hybrid Journal   (Followers: 1)
Journal of the Mexican Chemical Society     Open Access   (Followers: 1)
Journal of Theoretical and Computational Chemistry     Hybrid Journal   (Followers: 7)
Journal of Theoretical Chemistry     Open Access  
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
JPC - Journal of Planar Chromatography - Modern TLC     Full-text available via subscription   (Followers: 6)
Jurnal Penelitian Sains (JPS)     Open Access  
Jurnal Teknologi Informasi     Open Access   (Followers: 3)
Kinetics and Catalysis     Hybrid Journal   (Followers: 3)
Korea-Australia Rheology Journal     Hybrid Journal  
Langmuir     Full-text available via subscription   (Followers: 35)
Latvian Journal of Chemistry     Open Access   (Followers: 1)
Lebensmittelchemie     Hybrid Journal   (Followers: 1)
Lipid Insights     Open Access   (Followers: 1)
Luminescence     Hybrid Journal   (Followers: 1)
Macromolecular Materials & Engineering     Hybrid Journal   (Followers: 4)
Macromolecular Rapid Communications     Hybrid Journal   (Followers: 4)
Macromolecular Research     Hybrid Journal  
Macromolecular Symposia     Hybrid Journal  
Macromolecular Theory and Simulations     Hybrid Journal  
Macromolecules     Full-text available via subscription   (Followers: 31)
Magnetic Resonance in Chemistry     Hybrid Journal   (Followers: 4)
Main Group Chemistry     Hybrid Journal  
Marine Chemistry     Hybrid Journal   (Followers: 4)
Marine Drugs     Open Access   (Followers: 4)
MATEC Web of Conferences     Open Access  
Materials Characterization     Hybrid Journal   (Followers: 21)
Materials Horizons     Full-text available via subscription  
Materials Research Bulletin     Hybrid Journal   (Followers: 16)
Materials Science Monographs     Full-text available via subscription   (Followers: 1)
Materials Science-Poland     Hybrid Journal  
Materials Sciences and Applications     Open Access   (Followers: 4)
MedChemComm     Full-text available via subscription   (Followers: 4)
Medicinal Chemistry Research     Hybrid Journal   (Followers: 10)
Metallography, Microstructure, and Analysis     Hybrid Journal   (Followers: 1)
Metallomics     Full-text available via subscription  
Micro and Nano Systems Letters     Open Access   (Followers: 1)
Microchimica Acta     Hybrid Journal   (Followers: 2)
Microporous and Mesoporous Materials     Hybrid Journal   (Followers: 3)
Modern Research in Catalysis     Open Access   (Followers: 2)
Molbank     Open Access  
Molecules     Open Access   (Followers: 3)
Molecules and Cells     Hybrid Journal   (Followers: 1)
Monatshefte für Chemie - Chemical Monthly     Hybrid Journal   (Followers: 3)
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 2)
MRS Bulletin     Full-text available via subscription   (Followers: 5)
MRS Online Proceedings     Full-text available via subscription   (Followers: 1)
Nachrichten aus der Chemie     Full-text available via subscription   (Followers: 1)
Nano Convergence     Open Access  
Nano Reviews     Open Access   (Followers: 15)

  First | 1 2 3 4 5 6 | Last

Journal Cover Photochemistry and Photobiology
   [3 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0031-8655 - ISSN (Online) 1751-1097
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 0.709]   [H-I: 86]
  • Design of a Gd‐DOTA‐phthalocyanine conjugate combining
           MRI‐contrast imaging and photosensitization properties as a
           potential molecular theranostic
    • Authors: Duygu Aydın Tekdaş; Ruslan Garifullin, Berna Şentürk, Yunus Zorlu, Umut Gundogdu, Ergin Atalar, Ayse B. Tekinay, Alexander A. Chernonosov, Yusuf Yerli, Fabienne Dumoulin, Mustafa O. Guler, Vefa Ahsen, Ayşe Gül Gürek
      Pages: n/a - n/a
      Abstract: The design and synthesis of a phthalocyanine ‐ Gd‐DOTA conjugate is presented to open the way to novel molecular theranostics, combining the properties of MRI contrast imaging with photodynamic therapy. The rational design of the conjugate integrates isomeric purity of the phthalocyanine core substitution, suitable biocompatibility with the use of polyoxo water‐solubilizing substituents, and a convergent synthetic strategy ended by the use of click chemistry to graft the Gd‐DOTA moiety to the phthalocyanine. Photophysical and photochemical properties, contrast imaging experiments and preliminary in vitro investigations proved that such a combination is relevant and lead to a new type of potential theranostic agent. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-16T01:52:30.89027-05:0
      DOI: 10.1111/php.12332
       
  • Photodynamic inactivation of bacterial and yeast biofilms with a cationic
           porphyrin
    • Authors: Sandra Beirão; Sara Fernandes, Joel Coelho, Maria A. F. Faustino, João P. C. Tomé, Maria G. P. M. S. Neves, Augusto C. Tomé, Adelaide Almeida, Angela Cunha
      Pages: n/a - n/a
      Abstract: The efficiency of 5,10,15,20‐tetrakis(1‐methylpyridinium‐4‐yl)porphyrin tetra‐iodide (Tetra‐Py+‐Me) in the photodynamic inactivation of single‐species biofilms of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans and mixed biofilms of S. aureus and C. albicans was evaluated. The effect on the extracellular matrix of P. aeruginosa was also assessed. Irradiation with white light up to an energy dose of 64.8 J cm‐2 in the presence of 20 μM of Tetra‐Py+‐Me Tetra‐Py+‐Me caused significant inactivation in all single‐species biofilms (3 ‐ 6 log reductions), although the susceptibility was attenuated in relation to planktonic cells. In mixed biofilms, the inactivation of S. aureus was as efficient as in single‐species biofilms but the susceptibility of C. albicans decreased. In P. aeruginosa biofilms, a reduction of 81% in the polysaccharides content of the matrix was observed after treatment with a 20 μM PS concentration and a total light dose of 64.8 J cm‐2. The results show that the Tetra‐Py+‐Me causes significant inactivation of the microorganisms, either in biofilms or in the planktonic form, and demonstrate that polysaccharides of the biofilm matrix may be a primary target of photodynamic damage. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-12T00:21:34.055195-05:
      DOI: 10.1111/php.12331
       
  • Proanthocyanidins from Grape Seeds Inhibit UV Radiation‐Induced
           Immune Suppression in Mice: Detection and Analysis of Molecular and
           Cellular Targets
    • Authors: Santosh K. Katiyar
      Pages: n/a - n/a
      Abstract: Ultraviolet (UV) radiation‐induced immunosuppression has been linked with the risk of skin carcinogenesis. Approximately, two million new cases of skin cancers, including melanoma and non‐melanoma, diagnosed each year in the USA and therefore have a tremendous bad impact on public health. Dietary phytochemicals are promising options for the development of effective strategy for the prevention of photodamaging effects of UV radiation including the risk of skin cancer. Grape seed proanthocyanidins (GSPs) are such phytochemicals. Dietary administration of GSPs with AIN76A control diet significantly inhibits UV‐induced skin tumor development as well as suppression of immune system. UV‐induced suppression of immune system is commonly determined using contact hypersensitivity (CHS) model which is a prototype of T cell‐mediated immune response. We present evidence that inhibition of UV‐induced suppression of immune system by GSPs is mediated through: (i) the alterations in immunoregulatory cytokines, interleukin (IL)‐10 and IL‐12, (ii) DNA repair, (iii) stimulation of effector T cells, and (iv) DNA repair‐dependent functional activation of dendritic cells in mouse model. These information have important implications for the use of GSPs as a dietary supplement in chemoprevention of UV‐induced immunosuppression as well as photocarcinogenesis. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-12T00:21:21.261632-05:
      DOI: 10.1111/php.12330
       
  • The effects of UV‐B radiation intensity on biochemical parameters
           and active ingredients in flowers of Qi chrysanthemum and Huai
           chrysanthemum
    • Authors: Xiao‐Qin Yao; Jian‐Zhou Chu, Xue‐Li He, Chao Si
      Pages: n/a - n/a
      Abstract: The paper studied UV‐B‐effects on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum during the bud stage. The experiment included four UV‐B radiation levels (CK, ambient UV‐B; T1, T2 and T3 indicated a 5%, 10% and 15% increase in ambient UV‐BBE, respectively) to determine the optimal UV‐B radiation intensity in regulating active ingredients level in flowers of two chrysanthemum varieties. Flower dry weight of two cultivars was not affected by UV‐B radiation under experimental conditions reported here. UV‐B treatments significantly increased the rate of superoxide radical production, hydrogen peroxide (H2O2) (except for T1) and malondialdehyde concentration in flowers of Huai chrysanthemum, and H2O2 concentration in flowers of Qi chrysanthemum. T2 and T3 treatments induced a significant increase in penylalanine ammonia lyase enzyme (PAL) activity, anthocyanins, proline, ascorbic acid, chlorogenic acid and flavone content in flowers of two chrysanthemum varieties, and there were no significant differences in PAL activity, ascorbic acid, flavone and chlorogenic acid content between the two treatments. These results indicated that appropriate UV‐B radiation intensity did not result in the decrease in flower yield, and could regulate PAL activity and increase active ingredients content in flowers of two chrysanthemum varieties. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-11T10:56:51.994649-05:
      DOI: 10.1111/php.12329
       
  • Directed improvement of Luciferin Regenerating Enzyme (LRE) binding
           properties: Implication of some conserved residues in luciferin binding
           domain
    • Authors: Roohullah Hemmati; Reza H. Sajedi, Nuredin Bakhtiari, Saman Hosseinkhani
      Pages: n/a - n/a
      Abstract: Luciferin regenerating enzyme (LRE) contributes to in vitro recycling of D‐luciferin to produce persistent and longer light emission by luciferase. Luciferin binding domains I and II among LREs regarded as potential candidates for luciferin‐binding sites. In this study, for the first time, amino acids T69, G75 and K77 located at luciferin binding domain I of LRE from L. turkestanicus (T‐LRE) substituted by using site‐directed mutagenesis. Single mutant T69R increased luciferase light output more than 2‐fold over a longer time in comparison with a wild‐type and other mutants of T‐LRE. Nevertheless, double mutant (K77E/T69R) increased the amount of bioluminescent signal more than 2‐fold over a short time. In addition, G75E, K77E and G75E/T69R mutants didn't improve luciferin‐luciferase in vitro bioluminescence. Based on our results, addition of K77E/G75E and K77E/G75E/T69R mutants caused intermediate changes in bioluminescence from in vitro luciferin‐luciferase reaction. These findings indicated that the amino acids in question are possible to be located within T‐LRE active site. It may also be suggested that substituted Arg69 (Arg218) plays an important role in luciferin binding and the existence of Gly75 as well as Lys77 is essential for T‐LRE which has already evolved to have different functions in nature. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-08T01:36:32.477959-05:
      DOI: 10.1111/php.12328
       
  • A New Series of Fluorescent Indicators for Super Acids
    • Authors: I‐Chih Shih; Yu‐Shan Yeh, I‐Che Wu, You‐Hua Chen, Jiun‐Yi Shen, Yi‐An Chen, Mei‐Lin Ho, Pi‐Tai Chou
      Pages: n/a - n/a
      Abstract: The photophysical properties of fluorescent Hammett acidity indicator derived from 3,4,5,6‐tetrahydrobis(pyrido[3,2‐g]indolo)[2,3‐a:3’,2’‐j]acridine (1a), 6‐bis(pyrido[3,2‐g]indol‐2’‐yl)pyridine (1b) and their analogues have been investigated in sulfuric acid solutions by means of absorption, fluorimetry, relaxation dynamics and computational approach. These new indicators undergo a reversible protonation process in the Hammett acidity range of H0 < 0, accompanied by a drastic increase of the bright blue‐green (1a) or yellow (1b) fluorescence intensity upon increasing the acidity. For 1a in H2SO4, the emission yield increases as large as 200 folds from pH = ‐0.41 to the Hammett acidity range of ‐5.17, the results of which are rationalized by a much increase of the steric hindrance upon third protonation toward the central pyridinic site, together with their accompanied changes of electronic configuration from charge transfer to a delocalized ππ* character in the lowest lying excited state. The combination of 1a and 1b renders a wide and linear range of H0 measurement from ‐1.2 to ‐5.1 detected by highly intensive fluorescence. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-07T02:09:17.116293-05:
      DOI: 10.1111/php.12326
       
  • Self‐aggregation of synthetic zinc chlorophyll derivatives
           possessing 31‐hydroxy or methoxy group and 131‐mono‐ or
           dicyanomethylene moiety in non‐polar organic solvents as models of
           chlorosomal bacteriochlorophyll‐d aggregates
    • Authors: Hitoshi Tamiaki; Masaki Kuno, Masaki Ohata
      Pages: n/a - n/a
      Abstract: Methyl 131‐(di)cyanomethylene‐pyropheophorbides were synthesized by Knoevenagel reactions of the corresponding 131‐oxo‐chlorins prepared from modifying chlorophyll‐a with malononitrile or cyanoacetic acid. Alternatively, methyl 131‐cyanomethylene‐pyropheophorbides were produced by Wittig reactions of 131‐oxo‐chlorins with Ph3P=CHCN. Self‐aggregation of zinc complexes of the semi‐synthetic chlorophyll derivatives possessing a hydroxy or methoxy group at the 31‐position was examined in 1%(v/v) tetrahydrofuran or dichloromethane and hexane by electronic absorption and circular dichroism spectroscopy. Although intermolecular hydrogen‐bonding between the 31‐hydroxy and 131‐oxo groups of bacteriochlorophylls‐c/d/e/f was essential for their self‐aggregation in natural light‐harvesting antenna systems (= chlorosomes), zinc 31‐hydroxy‐131‐di/monocyanomethylene‐chlorins self‐aggregated in the less/lesser polar organic solvents to form chlorosome‐like large oligomers in spite of lacking the 131‐oxo moiety as the hydrogen‐bonding acceptor. Zinc 31‐methoxy‐131‐dicyanomethylene‐chlorin gave similar self‐aggregates regardless of lack of both the 31‐hydroxy and 131‐oxo groups. The present self‐aggregation was ascribable to stronger coordination of the 31‐oxygen atom to the central zinc than the conventional systems, where the electron‐withdrawing cyano group(s) increased the coordinative ability of the central zinc through chlorin π‐system. This article is protected by copyright. All rights reserved.
      PubDate: 2014-08-06T10:35:26.842727-05:
      DOI: 10.1111/php.12327
       
  • Hydroxyl Radical as an unlikely Key Intermediate in the Photodegradation
           of Emerging Pollutants
    • Authors: Gemma M. Rodriguez‐Muñiz; Juan Gomis, Antonio Arques, Ana M. Amat, M. Luisa Marin, Miguel A. Miranda
      Pages: n/a - n/a
      Abstract: In this work a kinetic model, in combination with time‐resolved experiments, is applied to assess the involvement of •OH in the photodegradation of emerging pollutants (EPs) by means of advanced oxidation processes. By contrast with the general assumption, quenching of the short‐lived •OH in the real waters by the (highly diluted) EPs must be very inefficient, so removal of EPs cannot purely rely on the generation and reaction of •OH. This suggests that more complex pathways have to be considered to explain the photodegradation of EPs actually achieved under the employed oxidative conditions, possibly involving other reactive species with longer lifetimes or chain degradation processes. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-28T03:59:40.0529-05:00
      DOI: 10.1111/php.12325
       
  • Rapid sonosynthesis of N‐doped nano TiO2 on wool fabric at low
           temperature: Introducing Self‐cleaning, Hydrophilicity,
           Antibacterial/Antifungal Properties with low Alkali Solubility, Yellowness
           and Cytotoxicity
    • Authors: Amir Behzadnia; Majid Montazer, Abousaeid Rashidi, Mahnaz Mahmoudi Rad
      Pages: n/a - n/a
      Abstract: Nano nitrogen‐doped titanium dioxide were rapidly prepared by hydrolysis of titanium isopropoxide at 75‐80 °C using in situ sonochemical synthesis by introducing ammonia. Various concentrations of titanium isopropoxide were examined to deposit nano nitrogen‐doped titanium dioxide through impregnation of the wool fabric in ultrasound bath followed by curing. The antibacterial/antifungal activities of wool samples were assessed against two common pathogenic bacteria including Escherichia coli and Staphylococcus aureus and the diploid fungus Candida albicans. The sonotreated wool fabrics indicated no adverse effects on human dermal fibroblasts. The presence of nano‐particles on the sonotreated wool fabrics were confirmed by FE‐SEM images and EDS patterns and X‐ray mapping and the crystalline size of nano‐particles were estimated through XRD results. The role of both pH and precursor concentration on the various properties of the fabric was investigated and the optimized conditions introduced using response surface methodology. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-28T03:59:39.080091-05:
      DOI: 10.1111/php.12324
       
  • Hypericin Damages the Ectatic Capillaries in a Roman Cockscomb Model and
           Inhibits the Growth of Human Endothelial Cells More Potently Than
           Hematoporphyrin Does Through Induction of Apoptosis
    • Authors: Zhuo‐heng Li; De‐sheng Meng, Yuan‐yuan Li, Lai‐chun Lu, Cai‐ping Yu, Qian Zhang, Hai‐yan Guan, Chen‐wen Li, Xue Yang, Ruo‐qiu Fu
      Pages: n/a - n/a
      Abstract: Hypericin (HY) is a promising photosensitizer (PS) for use in photodynamic therapy (PDT). Port‐wine stains (PWSs) are congenital superficial dermal capillary malformations. In this study, we evaluated the photocytotoxic effects of HY for PDT in human vascular endothelial cells and a chicken cockscomb model. HY significantly inhibited the growth of human umbilical vein endothelial cells (HUVECs), as determined by colorimetric assays and morphological observation, and flow cytometry assays indicated induction of apoptosis and collapse of the mitochondrial membrane potential. In addition, HY more effectively inhibited growth of and induced apoptosis in HUVECs compared with hematoporphyrin (HP). Further experiments performed in a Roman chicken cockscomb model also showed a clear photocytotoxic effect on the cockscomb dermal capillary upon intravenous injection of HY. This effect may be due to the role of HY in the induction of apoptosis. Transmission electron microscopical analysis showed mitochondrial morphological changes such as incomplete ridges and swelling, and immunohistochemical assays showed an increase in the release of cytochrome c. In conclusion, HY exhibited a greater photocytotoxic activity than did HP toward the growth of endothelial cells and may thus represent a potent PS for PWS PDT. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-26T02:42:55.177775-05:
      DOI: 10.1111/php.12323
       
  • ROS and p53 in Regulation of UVB‐induced HDM2 Alternative Splicing
    • Authors: Lingying Tong; Shiyong Wu
      Pages: n/a - n/a
      Abstract: Alternative splicing plays an important role in proteasome diversity and gene expression regulation in eukaryotic cells. Hdm2, the human homolog of mdm2 (murine double minute oncogene 2), is known to be an oncogene as its role in suppression of p53. Hdm2 alternative splicing, occurs in both tumor and normal tissues, is believed to be a response of cells for cellular stress, and thus modulate p53 activity. Therefore, understanding the regulation of hdm2 splicing is critical in elucidating the mechanisms of tumor development and progression. In this study, we determined the effect of ultraviolet B light (UVB) on alternative splicing of hdm2. Our data indicated that UVB (50 mJ cm−2) alone is not a good inducer of alternative splicing of hdm2. The less effectiveness could be due to the induction of ROS and p53 by UVB because removing ROS by L‐NAC (10 mm) in p53 null cells could lead to alternative splicing of hdm2 upon UVB irradiation. Hdm2, the human homologue of mdm2 (murine double minute oncogene 2), is an oncogene for its role in suppression of p53. Hdm2 alternative splicing, occurs in both tumor and normal tissues, is suggested to be a response of cells for cellular stress, and thus modulate p53 activity. In this study, we demonstrated that UVB is weaker inducer of alternative splicing than UVC is. We also provided evidences that the UV‐induced alternative splicing is promoted by DNA‐damage, but suppressed by ROS formation and p53 activity of the irradiated cells.
      PubDate: 2014-07-26T00:02:01.70935-05:0
      DOI: 10.1111/php.12306
       
  • UVB Irradiation Enhances TiO2 Nanoparticle‐induced Disruption of
           Calcium Homeostasis in Human Lens Epithelial Cells
    • Authors: Qiuxin Wu; Dadong Guo, Yuxiang Du, Dongmei Liu, Daoguang Wang, Hongsheng Bi
      Pages: n/a - n/a
      Abstract: Currently, titanium dioxide nanoparticles (TiO2 NPs) have been widely used in various applications including cosmetics, food additives and biomedicine. However, there are few reports available using TiO2 NPs to treat ocular diseases. Posterior capsular opacification (PCO) is the most frequent complication after cataract surgery, which is induced by the proliferation and migration of lens epithelial cells. Thus, inhibiting the proliferation of lens epithelial cells will efficiently reduce the occurrence of PCO. In this study, we investigated the effects of TiO2 NPs on HLE B‐3 cells with or without ultraviolet B (UVB) irradiation in vitro. We found that TiO2 NPs can inhibit HLE B‐3 cell growth, cause the elevation of intracellular [Ca2+], produce excessive reactive oxygen species (ROS), further reduce Ca2+‐ATPase activity and decrease the expression of plasma membrane calcium ATPase 1 (PMCA1), finally disrupt the intracellular calcium homeostasis and induce cell damage. Importantly, UVB irradiation can apparently enhance these effects on HLE B‐3 cells in the presence of TiO2 NPs. Taken together, the generation of excessive ROS and the disruption of intracellular calcium homeostasis may be both involved in TiO2 nanoparticle‐induced HLE B‐3 cell damage under UVB irradiation. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-24T11:09:55.145055-05:
      DOI: 10.1111/php.12322
       
  • Photooxidation of Tryptophan Leading to 2‐Aminoacetophenone ‐
           A Possible Reason for the Untypical Aging Off‐flavor in Wine
    • Authors: Nora Horlacher; Wolfgang Schwack
      Pages: n/a - n/a
      Abstract: 2‐Aminoacetophenone (AAP) was recognized as the key compound for the so‐called untypical aging off‐flavor (UTA) in Vitis vinifera wines. In this study, it was shown that AAP can be formed by photooxidation of free and protein‐bound tryptophan (TRP) in combination with a subsequent storage in model wine. Solutions of TRP and lysozyme were exposed to artificial sunlight both in the presence and in the absence of the photosensitizer riboflavin. Aliquots of the irradiation batches were stored in model wine solutions containing tartaric acid, sulfite, and ethanol in different combinations. AAP formation could be identified from both free and bound (lysozyme) TRP, while free TRP resulted in higher yields. The presence of riboflavin during irradiation generally favored the AAP formation. AAP formation increased with increasing irradiation times, but AAP was not detectable, if TRP was directly incubated in model wine. Not only the irradiation time but also the storage time of model wines favored the formation of AAP. Concerning the model wine composition, it became evident that the presence of tartaric acid resulted in the highest AAP formation during storage. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-22T01:48:41.844654-05:
      DOI: 10.1111/php.12321
       
  • Validation and application of a model of oxygen consumption and diffusion
           during photodynamic therapy in vitro
    • Authors: Mark A. Weston; Michael S. Patterson
      Pages: n/a - n/a
      Abstract: The photophysical parameters for the photosensitizer Pd(II) meso‐Tetra(4‐carboxyphenyl) porphine (PdT790) acquired in a previous study were incorporated into the PDT oxygen diffusion models for cell suspensions and cell monolayers. The time dependent phosphorescence signals generated by the diffusion models are shown to match signals previously measured by Weston and Patterson when reasonable physical and photophysical parameters are used. Simulations were performed to investigate the effects of metabolic and photodynamic oxygen consumption rates on the PDT dose in each of the treatment geometries. It was found that in cell suspensions of less than 1 million cells per mL, PDT should not be inhibited by hypoxia if the photodynamic consumption rate is less than 1 mM s−1. For cell monolayers the optimal photodynamic oxygen consumption rate was found to depend on the metabolic rate of oxygen consumption. If cells remained well oxygenated in the absence of PDT, then maximum PDT dose was delivered with the lowest practical photodynamic oxygen consumption rate. Simulations of PDT treatments for multicell tumor spheroids showed that large anoxic cores develop within the spheroids and, as a consequence, less PDT dose is delivered in comparison to similar treatments in cell suspensions and cell monolayers. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-21T01:28:08.557303-05:
      DOI: 10.1111/php.12320
       
  • Enhanced Light‐Harvesting Capacity by Micellar Assembly of Free
           Accessory Chromophores and LH1‐like Antennas
    • Authors: Michelle A. Harris; Tuba Sahin, Jianbing Jiang, Pothiappan Vairaprakash, Pamela S. Parkes‐Loach, Dariusz M. Niedzwiedzki, Christine Kirmaier, Paul A. Loach, David F. Bocian, Dewey Holten, Jonathan S. Lindsey
      Pages: n/a - n/a
      Abstract: Biohybrid light‐harvesting antennas are an emerging platform technology with versatile tailorability for solar‐energy conversion. These systems combine the proven peptide scaffold unit utilized for light harvesting by purple photosynthetic bacteria with attached synthetic chromophores to extend solar coverage beyond that of the natural systems. Herein, synthetic unattached chromophores are employed that partition into the organized milieu (e.g., detergent micelles) that house the LH1‐like biohybrid architectures. The synthetic chromophores include a hydrophobic boron‐dipyrrin dye (A1) and an amphiphilic bacteriochlorin (A2), which transfer energy with reasonable efficiency to the bacteriochlorophyll acceptor array (B875) of the LH1‐like cyclic oligomers. The energy‐transfer efficiencies are markedly increased upon covalent attachment of a bacteriochlorin (B1 or B2) to the peptide scaffold, where the latter likely acts as an energy‐transfer relay site for the (potentially diffusing) free chromophores. The efficiencies are consistent with a Förster (through‐space) mechanism for energy transfer. The overall energy‐transfer efficiency from the free chromophores via the relay to the target site can approach those obtained previously by relay‐assisted energy transfer from chromophores attached at distant sites on the peptides. Thus, the use of free accessory chromophores affords a simple design to enhance the overall light‐harvesting capacity of biohybrid LH1‐like architectures. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-21T01:28:02.651894-05:
      DOI: 10.1111/php.12319
       
  • Effect of Immunosuppressants Tacrolimus and Mycophenolate Mofetil on the
           Keratinocyte UVB Response
    • Authors: Mei Ming; Baozhong Zhao, Lei Qiang, Yu‐Ying He
      Pages: n/a - n/a
      Abstract: Non‐melanoma skin cancer, derived from epidermal keratinocytes, is the most common malignancy in organ transplant recipients, causes serious morbidity and mortality, and is strongly associated with solar ultraviolet (UV) exposure. Preventing and treating skin cancer in these individuals has been extraordinarily challenging. Following organ transplantation, the immunosuppressants are used to prevent graft rejection. Until now, immunosuppression has been assumed to be the major factor leading to skin cancer in this setting. However, the mechanism of skin carcinogenesis in organ transplant recipients has not been understood to date; specifically, it remains unknown whether these cancers are immunosuppression‐dependent or ‐independent. In particular, it remains poorly understood what is the mechanistic carcinogenic action of the newer generation of immunosuppressants including tacrolimus and mycophenolate mofetil (MMF). Here we show that tacrolimus and MMF impairs UVB‐induced DNA damage repair and apoptosis in human epidermal keratinocytes. In addition, tacrolimus inhibits UVB‐induced checkpoint signaling. However, MMF had no effect. Our findings have demonstrated that tacrolimus and MMF compromises proper UVB response in keratinocytes, suggesting an immunosuppression‐independent mechanism in the tumor‐promoting action of these immunosuppressants. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-21T01:27:27.76301-05:0
      DOI: 10.1111/php.12318
       
  • In Vitro Investigations on the Effect of Dermal Fibroblasts on
           Keratinocyte Responses to Ultraviolet B Radiation
    • Authors: Tara L Fernandez; Derek R Van Lonkhuyzen, Rebecca A Dawson, Michael G Kimlin, Zee Upton
      Pages: n/a - n/a
      Abstract: Exposure to ultraviolet radiation (UVR) is closely linked to the development of skin cancers in humans. The ultraviolet B (UVB) radiation wavelength (280‐320 nm), in particular, causes DNA damage in epidermal keratinocytes, which are linked to the generation of signature pre‐malignant mutations. Interactions between dermal fibroblasts and keratinocytes play a role in epidermal repair and regeneration after UVB‐induced damage. To investigate these processes, established two and three‐dimensional culture models were utilised to study the impact of fibroblast‐keratinocyte crosstalk during the acute UVB response. Using a co‐culture system it was observed that fibroblasts enhanced keratinocyte survival and the repair of cyclobutane pyrimidine dimers (CPDs) after UVB radiation exposure. These findings were also mirrored in irradiated human skin co‐culture models employed in this study. Fibroblast co‐culture was shown to play a role in the expression and activation of members of the apoptotic cascade, including caspase‐3 and Bad. Interestingly, the expression and phosphorylation of p53, a key player in the regulation of keratinocyte cell fate post‐irradiation, was also shown to be influenced by fibroblast‐produced factors. This study highlights the importance of synergistic interactions between fibroblasts and keratinocytes in maintaining a functional epidermis while promoting repair and regeneration following UVB radiation‐induced damage. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-18T03:00:24.137746-05:
      DOI: 10.1111/php.12317
       
  • Red‐Light interferes in UVA‐induced Photoaging of Human Skin
           fibroblast Cells
    • Authors: Tianhui Niu; Yan Tian, Qu Ren, Lizhao Wei, Xiaoxin Li, Qing Cai
      Pages: n/a - n/a
      Abstract: The possible regulation mechanism of red light was determined to discover how to retard UVA‐induced skin photoaging. Human skin fibroblasts were cultured and irradiated with different doses of UVA, thus creating a photoaging model. Fibroblasts were also exposed to a sub‐toxic dose of UVA combined with a red light‐emitting diode (LED) for 5 continuous days. Three groups were examined: control, UVA and UVA plus red light. Cumulative exposure doses of UVA were 25 J/cm2, and the total doses of red light were 0.18 J/cm2. Various indicators were measured before and after irradiation, including cell morphology, viability, β‐galactosidase staining, apoptosis, cycle phase, the length of telomeres and the protein levels of photoaging‐related genes. Red light irradiation retarded the cumulative low‐dose UVA irradiation‐induced skin photoaging, decreased the expression of senescence‐associated β‐galactosidase, up‐regulated SIRT1 expression, decreased matrix metalloproteinase MMP‐1 and the acetylation of p53 expression, reduced the horizon of cell apoptosis, and enhanced cell viability. Furthermore, the telomeres in UVA‐treated cells were shortened compared to those of cells in the red light groups. These results suggest that red light plays a key role in the anti‐photoaging of human skin fibroblasts by acting on different signaling transduction pathways. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-12T06:29:10.737088-05:
      DOI: 10.1111/php.12316
       
  • The injury and cumulative effects on human skin by UV exposure from
           artificial fluorescence emission
    • Authors: Yan. Tian; Wei. Liu, TianHui. Niu, CaiHong. Dai, Xiaoxin. Li, Caijuan. Cui, Xinyan. Zhao, Yaping. E, Hui. Lu
      Pages: n/a - n/a
      Abstract: The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low dose group with a cumulative dose of 50 J/cm2 which was equivalent to irradiation of the face during indoor work for 1.5 years; and high dose group with 1000 J/cm2 cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin colour changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin oedema, light colour and unclear staining collagen fibres in the dermis, and elastic fibre fragmentation. In addition, MMP‐1, p53 and SIRT1 expression was also increased. Long‐term exposure of low dose UVA radiation enhanced skin photoageing.The safety of the fluorescent lamp needs our attention. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-11T01:39:39.948528-05:
      DOI: 10.1111/php.12315
       
  • Study of the Photodegradation Kinetics and Pathways of Hexaflumuron in
           Liquid Media
    • Authors: Lu Chengying; Xing Yin, Xiaofeng Liu, Minghua Wang
      Pages: n/a - n/a
      Abstract: Hexaflumuron, one of the benzoylphenylurea insect growth regulators, can be leached into surface water and thus having a potential impact on aquatic organisms In this study, the photodegradation processes of hexaflumuron under high‐pressure mercury lamp irradiation were assessed. The photodegradation kinetics were studied, as were the effects of pH,different light sources, organic solvents and environmental substances, including nitrate ions (NO3−), nitrite ions (NO2−), ferrous ions (Fe2+), ferric ions (Fe3+), humic acid, sodium dodecyl sulfate (SDS) and hydrogen peroxide (H2O2). Three photodegradation products in methanol were identified by gas chromatography‐mass spectrometry (GC‐MS). In general, the degradation of hexaflumuron followed first‐order kinetics. In the four media studied, the photodegradation rate order was n‐hexane > methanol > ultrapure water > acetone. Faster degradation was observed under high‐pressure mercury lamp irradiation than under xenon lamp irradiation. The pH had a considerable effect, with the most rapid degradation occurring at pH 5.0. The photodegradation rate of hexaflumuron was promoted in the presence of NO3−, NO2−, Fe2+, humic acid, SDS and H2O2 but inhibited by Fe3+. Moreover, the presumed photodegradation pathway was proposed to be the cleavage of the urea linkage. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-11T01:39:36.74197-05:0
      DOI: 10.1111/php.12314
       
  • Observation of in vivo morphologic changes after carbon dioxide ablative
           fractional laser in a mouse model using non‐invasive imaging
           modalities and comparison with histologic examination
    • Authors: Kwang Ho Yoo; Tae Rin Kwon, So Young Kim, Yi Seop Song, Young Sook Cheon, Yu Mi Kim, In Kwon Yeo, Eun Jung Ko, Kapsok Li, Myeung Nam Kim, Beom Joon Kim
      Pages: n/a - n/a
      Abstract: Ablative fractional carbon dioxide (CO2) lasers have been widely used for several types of cosmetic dermatosis. A number of previous studies have evaluated this technique in animals or human beings by observing morphologic changes using an invasive modality such as skin biopsy. In this study, we assessed in vivo skin changes after CO2 ablative fractional laser treatment in a mouse model using non‐invasive imaging modalities (Folliscope® and Visioscan 98®), and each results was compared with data from histologic examination. An ablative fractional CO2 laser was applied with different pulse energy between 7 to 35 mJ/microspot. As results of above methods, we also confirmed that the CO2 ablative fractional laser generated injuries with increasing width and depth with increasing pulse energy. Although numerous papers have described application of this laser in vivo skin specimens, our study evaluated the feasibility of using relative non‐invasive imaging modalities for assessing the outcome of laser ablation. Based on our data, we suggest that these technologies may be useful alternative modalities for assessing laser ablation that are easier to perform and less invasive than skin biopsy. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-11T01:39:34.393127-05:
      DOI: 10.1111/php.12313
       
  • Sun‐protection Provided by Regulation School Uniforms in Australian
           Schools: An Opportunity to Improve Personal Sun‐protection During
           Childhood
    • Authors: Denise Turner; Simone Lee Harrison
      Pages: n/a - n/a
      Abstract: Childhood sun‐exposure is linked to excessive pigmented mole development and melanoma risk. Clothing provides a physical barrier, protecting skin from ultraviolet radiation (UVR). Extending sleeves to elbow‐length and shorts to knee‐length has been shown to significantly reduce mole acquisition in pre‐schoolers from tropical Queensland. We used publicly‐available uniform images and guidelines from primary schools in Townsville (latitude 19.25°S, n=43 schools), Cairns (16.87°S, n=46), and the Atherton Tablelands (17.26°S, n=23) in tropical Australia to objectively determine the body surface proportion covered by regulation school uniforms. Uniforms of non‐government, large (≥800 students), urban, educationally‐advantaged schools with comprehensive sun‐protection policies covered more skin than those of government schools (63.2% Vs 62.0%; p
      PubDate: 2014-07-09T11:57:44.861834-05:
      DOI: 10.1111/php.12312
       
  • Chemical and Biological Mechanisms of Pathogen Reduction Technologies
    • Authors: Janna M. Mundt; Lindsay Rouse, Jeroen den Bossche, Raymond P. Goodrich
      Pages: n/a - n/a
      Abstract: Within the last decade new technologies have been developed and implemented which employ light, often in the presence of a photosensitizer, to inactivate pathogens that reside in human blood products for the purpose of transfusion. These pathogen reduction technologies attempt to find the proper balance between pathogen kill and cell quality. Each system utilizes various chemistries that not only impact which pathogens they can inactivate and how, but also how the treatments affect the plasma and cellular proteins and to what degree. This paper aims to present the various chemical mechanisms for pathogen reduction in transfusion medicine that are currently practiced or in development. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-06T23:55:02.76603-05:0
      DOI: 10.1111/php.12311
       
  • Cellular Changes Associated with the Acclimation of the Intertidal Sea
           Anemone Actinia tenebrosa to Ultraviolet Radiation.
    • Authors: Victor Mauricio Cubillos; Miles D. Lamare, Barrie M. Peake, David J. Burritt
      Pages: n/a - n/a
      Abstract: To assess the relative importance of long‐ and short‐term cellular defence mechanisms in seasonally UV‐R acclimated Actinia tenebrosa (Anthozoa, Actiniidae), individuals were exposed to summer doses of PAR, UV‐A, UV‐B and enhanced UV‐B (20%) for a period of 4 days. Mycosporine‐like amino acids (MAAs) and cyclobutane pyrimidine dimer (CPD) concentrations were quantified, while oxidative damage to lipids and proteins, and the activities/levels of the antioxidant enzymes SOD, CAT, GR, GPOX and total glutathione were determined. Our results show that summer UV‐R acclimated individuals had a higher UV‐R tolerance, with no significant increases in CPDs levels, than winter acclimated sea anemones possibly due to higher MAA concentrations. Summer acclimated individuals showed increased lipid and protein oxidation and GPOX activity only when they were exposed to UV‐B at 20% above ambient UV‐R levels. In contrast, winter acclimated sea anemones showed elevated levels of oxidative damage, GPOX and SOD activities after exposure to UV‐A or UV‐B at ambient and elevated levels. Thus, this study indicates that long‐term UV‐R acclimation mechanisms such as the accumulation of MAAs could be more important than short term increases in antioxidant defences with respect to reducing indirect UV‐R damage in intertidal sea anemones. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-05T10:29:03.403438-05:
      DOI: 10.1111/php.12310
       
  • Disinfection Of Escherichia Coli Gram Negative Bacteria Using Surface
           Modified TiO2: Optimization Of Ag Metallization And Depiction Of Charge
           Transfer Mechanism
    • Authors: L. Gomathi Devi; Nagaraj B
      Pages: n/a - n/a
      Abstract: The antibacterial activity of silver deposited TiO2 (Ag‐TiO2) against Gram negative Escherichia coli bacteria was investigated by varying the Ag metal content from 0.10% ‐ 0.50% on the surface of TiO2. Ag depositions by photoreduction method were found to be stable. Surface silver metallization was confirmed by EDAX and XPS studies. Photoluminescence studies shows that charge carrier recombination is less for 0.1% Ag‐TiO2 and this catalyst shows superior bactericidal activity under solar light irradiation compared to Sol gel TiO2 (SG‐TiO2) due to the surface plasmon effect. The energy levels of deposited Ag are dependent on the Ag content and it varies from ‐4.64 eV to ‐1.30 eV with respect to vacuum energy level based on atomic silver to bulk silver deposits. The ability of electron transfer from Ag deposit to O2 depends on the position of the energy levels. 0.25% and 0.50% Ag depositions showed detrimental effect on bactericidal activity due to the mismatch of energy levels. The effect of the EROS (External generation of the Reactive Oxygen Species by 0.1% Ag‐TiO2) and IROS (Interior generation of Reactive Oxygen Species within the bacteria) on the bactericidal inactivation is discussed in detail. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-03T09:48:25.04107-05:0
      DOI: 10.1111/php.12308
       
  • Photoactive hybrid materials of lanthanide (Eu3+, Tb3+, Sm3+)
           beta‐diketonates and polymer resin through ionic liquid bridge
    • Authors: Ying Mei; Bing Yan
      Pages: n/a - n/a
      Abstract: A special multifunctional ionic liquid compound (1‐methyl‐3‐(2‐(thiocarboxyoxy)‐ethyl)‐2H‐imidazole‐1,3‐diium bromide (SHIL)) is used as the chemical bridge to link lanthanide beta‐diketonates and polymer resin, which are designated as Ln(L)4‐SHIL‐WR/MR (Ln = Eu, Tb, Sm; L= thenoyltrifluoroacetonate (TTA), acetylacetonate (AA), dibenzoylmethane (DBM); WR = Wang resin, MR = Merrifield resin). Among SHIL and polymer resin are assembled to form covalently bonded system through condensation reaction. Then tetrakis lanthanide beta‐diketonates are linked to SHIL through ion exchange reaction. Physical characterization and especially the photoluminescent performance of the multi‐component hybrids are studied. The hybrid materials possess good stability and excellent luminescent property. The results provide useful path to obtain luminescent hybrids for further practical application. This article is protected by copyright. All rights reserved.
      PubDate: 2014-07-02T00:20:22.559681-05:
      DOI: 10.1111/php.12307
       
  • On the Role of Exponential Smoothing in Circadian Dosimetry
    • Authors: Luke L. A. Price
      Abstract: The effects lighting has on health through modulation of circadian rhythms are becoming increasingly well documented. Data are still needed to show how light exposures are influenced by architecture and lighting design and circadian dosimetry analyses should provide duration, phase and amplitude measures of 24-hour exposure profiles. Exponential smoothing is used to derive suitable metrics from 24-hour light measurements collected from private dwellings. A further application of these modified exposure time series as physiological models of the light drive is discussed. Unlike previous light drive models, the dose rate persists into periods of darkness following exposures. Comparisons to long duration exposure studies suggest this type of persistent light drive model could be incorporated into contemporary physiological models of the human circadian oscillator. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-24T08:30:20.944453-05:
      DOI: 10.1111/php.12282
       
  • Effects of Ultraviolet Radiation (UVA+UVB) on Young Gametophytes of
           Gelidium floridanum: Growth rate, Photosynthetic Pigments, Carotenoids,
           Photosynthetic Performance and Ultrastructure
    • Authors: Carmen Simioni; Éder C. Schmidt, Marthiellen R. de L. Felix, Luz Karime Polo, Ticiane Rover, Marianne Kreusch, Debora T. Pereira, Fungyi Chow, Fernanda Ramlov, Marcelo Maraschin, Zenilda L. Bouzon
      Abstract: This study investigated the effects of radiation (PAR+UVA+UVB) on the development and growth rates of young gametophytes of Gelidium floridanum. In addition, photosynthetic pigments were quantified, carotenoids identified, and photosynthetic performance assessed. Over a period of 3 days, young gametophytes were cultivated under laboratory conditions and exposed to photosynthetically active radiation (PAR) at 80 μmol photons m−2 s−1 and PAR+UVA (0.70 W m−2) +UVB (0.35 W m−2) for 3 h per day. The samples were processed for light and electron microscopy to analyze the ultrastructure features, as well as carry out metabolic studies of growth rates, quantify the content of photosynthetic pigments, identify carotenoids and assess photosynthetic performance. PAR+UVA+UVB promoted increase of cell wall thickness, accumulation of floridean starch grains in the cytoplasm and disruption of chloroplast internal organization. Algae exposed to PAR+UVA+UVB also showed a reduction in growth rate of 97%. Photosynthetic pigments, in particular, phycoerythrin and allophycocyanin contents, decreased significantly from UV radiation exposure. This result agrees with the decrease of photosynthetic performance observed after exposure to UVR, as measured by a decrease in the electron transport rate (ETR), where values of ETRmax declined approximately 44.71%. It can be concluded that radiation is a factor that affects the young gametophytes of G. floridanum at this stage of development. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-23T05:16:45.736292-05:
      DOI: 10.1111/php.12296
       
  • Neurotransmitter transporter family including SLC6A6 and SLC6A13
           contributes to the 5‐aminolevulinic acid (ALA)‐induced
           accumulation of protoporphyrin IX and photo‐damage, through uptake
           of ALA by cancerous cells
    • Authors: Tai Tien Tran; Anfeng Mu, Yuka Adachi, Yasushi Adachi, Shigeru Taketani
      Abstract: δ‐Aminolevulinic acid (ALA)‐induced protoporphyrin accumulation is widely used in the treatment of cancer, as photodynamic therapy (PDT). To clarify the mechanisms of ALA uptake by tumor cells, we have examined the ALA‐induced accumulation of protoporphyrin by the treatment of colon cancer DLD‐1 and epithelial cancer HeLa cells with γ‐aminobutyric acid (GABA)‐related compounds. When the cells were treated with GABA, taurine and β‐alanine, the level of protoporphyrin was decreased, suggesting that plasma membrane transporters involved in the transport of neurotransmitters contribute to the uptake of ALA. By transfection with neurotransmitter transporters SLC6A6, SLC6A8 and SLC6A13 cDNA, the ALA‐ and ALA methylester‐dependent accumulation of protoporphyrin markedly increased in HEK293T cells, dependent on an increase in the uptake of ALA. When ALA‐treated cells were exposed to white light, the extent of photo‐damage increased in SLC6A6‐ and SLC6A13‐expressing cells. Conversely, knockdown of SLC6A6 or SLC6A13 with siRNAs in DLD‐1 and HeLa cells decreased the ALA‐induced accumulation. The expression of SLC6A6 and SLC6A13 was found in some cancer cell lines. Immunohistochemical studies revealed that the presence of these transporters was elevated in colon cancerous cells. These results indicated that neurotransmitter transporters including SLC6A6 and SLC6A13 mediate the uptake of ALA and can play roles in the enhancement of ALA‐induced accumulation of protoporphyrin in cancerous cells. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-23T05:15:17.916808-05:
      DOI: 10.1111/php.12290
       
  • Retarded Photooxidation of Cyamemazine in Biomimetic Microenvironments
    • Authors: Daniel Limones-Herrero; Raúl Pérez-Ruiz, M. Consuelo Jiménez, Miguel A. Miranda
      Pages: n/a - n/a
      Abstract: Cyamemazine (CMZ) is a neuroleptic drug that mediates cutaneous phototoxicity in humans. Here, the photobehavior of CMZ has been examined within α1-acid glycoproteins, β- and γ-cyclodextrins and SDS micelles. In all these microenvironments, CMZ emission was enhanced and blue-shifted, and its lifetime was longer. Irradiation of the entrapped drug at 355 nm, under air; led to the N,S-dioxide. Within glycoproteins or SDS micelles the reaction was clearly slower than in phosphate buffered solution (PBS); protection by cyclodextrins was less marked. Transient absorption spectroscopy in PBS revealed formation of the triplet state (3CMZ*) and the radical cation (CMZ+•). Upon addition of glycoprotein, the contribution of CMZ+• became negligible, whereas 3CMZ* dominated the spectra; in addition, the triplet lifetime became considerably longer. In cyclodextrins, this occurred to a lower extent. In all microheterogeneous systems, quenching by oxygen was slower than in solution; this was most remarkable inside glycoproteins. The highest protection from photooxidation was achieved inside SDS micelles. The results are consistent with photooxidation of CMZ through photoionization and subsequent trapping of the resulting radical cation by oxygen. This reaction is extremely sensitive to the medium and constitutes an appropriate probe for localization of the drug within a variety of biological compartments. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-20T22:47:16.822253-05:
      DOI: 10.1111/php.12303
       
  • A Tandem Mass Spectrometric Method for Singlet Oxygen Measurement
    • Authors: Maarit Karonen; Heta Mattila, Ping Huang, Fikret Mamedov, Stenbjörn Styring, Esa Tyystjärvi
      Abstract: Singlet oxygen, a harmful reactive oxygen species, can be quantified with the substance 2,2,6,6‐tetramethylpiperidine (TEMP) that reacts with singlet oxygen, forming a stable nitroxyl radical (TEMPO). TEMPO has earlier been quantified with electron paramagnetic resonance (EPR) spectroscopy. In the present study, we designed an ultra‐high‐performance liquid chromatographic – tandem mass spectrometric (UHPLC‐ESI‐MS/MS) quantification method for TEMPO and showed that the method based on multiple reaction monitoring (MRM) can be used for the measurements of singlet oxygen from both non‐biological and biological samples. Results obtained with both UHPLC‐ESI‐MS/MS and EPR methods suggest that plant thylakoid membranes produce 3.7 x 10‐7 molecules of singlet oxygen per chlorophyll molecule in a second when illuminated with the photosynthetic photon flux density of 2000 μmol m‐2s‐1. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-20T03:00:43.170111-05:
      DOI: 10.1111/php.12291
       
  • Xeroderma Pigmentosum in the United Kingdom;
    • Authors: Alan R Lehmann
      Abstract: The seminal discovery by James Cleaver of defective DNA repair in xeroderma pigmentosum (XP) opened up an ever‐expanding field of DNA repair‐related disorders. In addition it put XP on the map and has led to improved diagnosis, care and management of affected patients. In the UK, we recently established a multi‐disciplinary specialist clinic for XP patients. All XP patients in the UK are able to visit the clinic where they are examined and advised by a team of specialists with detailed knowledge of the different aspects of XP. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-19T01:55:47.802274-05:
      DOI: 10.1111/php.12301
       
  • Possible Involvement of a Tetrahydrobiopterin in Photoreception for
           UV‐B‐induced Anthocyanin Synthesis in Carrot
    • Authors: Junko Takeda; Rieko Nakata, Hiroshi Ueno, Akio Murakami, Mineo Iseki, Masakatsu Watanabe
      Abstract: Our previous studies of action spectra for UV‐B‐induced anthocyanin accumulation in cultured carrot cells indicated that a reduced form of pterin, possibly tetrahydrobiopterin, contributes to UV‐B photoreception. In this report, we provide additional evidence for the involvement of pterin in UV‐B light sensing. UV‐B‐induced phenylalanine ammonia‐lyase (PAL) activity was considerably suppressed by N‐acetylserotonin (an inhibitor of tetrahydrobiopterin biosynthesis), and this suppression was partially recovered by adding biopterin or tetrahydrobiobiopterin. In addition, protein(s) specifically bound to biopterin were detected by radiolabeling experiments in N‐acetylserotonin‐treated cells. Furthermore, diphenyleneiodonium, a potent inhibitor of electron transfer, completely suppressed UV‐B‐induced PAL activity. These results suggest the occurrence of an unidentified UV‐B photoreceptor (other than UVR8, the tryptophan‐based UV‐B sensor originally identified in Arabidopsis) with reduced pterin in carrot cells. After re‐examining published action spectra, we suggest that anthocyanin synthesis is coordinately regulated by these two UV‐B sensors. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-19T01:55:46.857696-05:
      DOI: 10.1111/php.12302
       
  • Comparative Antibacterial Efficacy of Photodynamic Therapy and Ultrasonic
           Irrigation Against Enterococcus faecalis In Vitro
    • Authors: Yanhuang Wang; Xiaojing Huang
      Abstract: Enterococcus faecalis poses a challenge to the efficacy of traditional root canal disinfection methods. This study was aimed to establish a synergistic root canal disinfection strategy combining ultrasonic irrigation with photodynamic therapy (PDT) together and to test its antibacterial efficacy against E. faecalis. Twenty‐seven bovine root canals infected with E. faecalis were randomly divided into three groups and treated with different disinfection methods as follows: ultrasonic irrigation with 2.5% NaOCl, methylene blue (MB)‐mediated PDT, or combined ultrasonic irrigation and PDT as described above. Quantification of E. faecalis was performed on the root canals before and immediately after the disinfection treatment. Residual bacteria were determined by counting colony‐forming units. Samples were randomly selected from the three groups, and the morphology of residual bacteria inside the dentinal tubules was studied by scanning electron microscopy. The number of surviving E. faecalis in the group treated with the combination method was significantly lower (P 
      PubDate: 2014-06-18T06:53:02.055236-05:
      DOI: 10.1111/php.12293
       
  • New Advances in Protection Against Solar Ultraviolet Radiation in Textiles
           for Summer Clothing
    • Authors: José Aguilera; María Victoria Gálvez, Cristina Sánchez-Roldán, Enrique Herrera-Ceballos
      Abstract: Clothing is considered one of the most important tools for photoprotection against harmful solar ultraviolet radiation (UVR). The standard for sun‐protective clothing is based on erythema despite other biological effects of UVR on the skin. We analyzed the potential protection against UVR in fabrics destined for summer clothing based on several action spectra. We examined 50 garments classified by type of fabric composition, structure of the fiber yarn and color. The ultraviolet protection factor was calculated based on fabric ultraviolet transmittance corrected for erythema according to the EU standard E‐13758 as well as the UVA transmittance of fabrics. UVR protection was also analyzed in base of different action spectra as for previtamin D3, nonmelanoma skin cancer, photoimmunosuppression and photoaging. Most knitted fabrics used for sports T‐shirts offered excellent ratings for ultraviolet protection while normal shirts showed very low ratings, particularly against photoaging. The cover is the most influential variable in fabric photoprotection, having an exponential relationship with the UPF. The relation between cover and UVA protection was linearly negative. Information about ultraviolet protection in textiles used for summer clothing should be included in labeling as some types of fabrics, especially those used for shirts, offer very low UVR protection. Microscopic analysis of different types of fabrics used in traditional summer clothing shows differences in structure, yarn and composition. Five different types of fabric were classified as follows: linen shirts (A), polyester shirts (B), T‐shirts (C), polo T‐shirts (D) and the latest generation of sport textiles (E), which leads to different abilities of light transmission, namely cover. Ultraviolet protection factor, based on the potential of protection against the erythematic fraction of UV radiation increases exponentially as the fabric cover does.
      PubDate: 2014-06-18T06:53:00.341326-05:
      DOI: 10.1111/php.12292
       
  • 5‐aminolaevulinicacid (ALA)‐loaded fullerene nanoparticles for
           in vitro and in vivo photodynamic therapy
    • Authors: Zhi Li; Li-li Pan, Fei-long Zhang, Xia-li Zhu, Yang Liu, Zhen-zhong Zhang
      Abstract: This report explores some properties of 80‐200 nm nanoparticles containing 5‐aminolevulinic acid (ALA) and fullerene (C60) for photodynamic therapy. Compared with ALA, the nanoparticles yielded more protoporphytin (PpIX) formation in cells and tissues and to a significant improvement in antitumor efficacy in tumor‐bearing mice. Maximum levels of PpIX were obtained 4 h after administration and selective PpIX formation in tumor was observed. These nanoparticles appear to be a useful vehicle for drug delivery purposes. In this paper, a procedure for preparing fullerene nanoparticles containing ALA was developed. The product alone exhibited no detectable toxicity in the dark and was superior to ALA alone in promoting PpIX biosynthesis and PDT efficacy both in culture and in a murine tumor model. These results suggest that this procedure could be the basis for an improved PDT protocol for cancer control. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-10T00:34:33.439093-05:
      DOI: 10.1111/php.12299
       
  • The Light Induced FOS Response in Melanopsin Expressing HEK‐293
           Cells Is Correlated to Melanopsin Quantity And Dependent on Light Duration
           And Irradiance
    • Authors: Birgitte Georg; Lene Rask, Jens Hannibal, Jan Fahrenkrug
      Abstract: We established a cell line (HEK‐hMel) expressing melanopsin in a tetracycline dependent manner to elucidate new aspects of melanopsin's light response. Different light stimuli were evaluated using FOS expression as response parameter. Immunoblotting was used to evaluate expression of melanopsin and FOS and qPCR to quantify FOS mRNA responses. The magnitude of the FOS response was found to correlate with the amount of melanopsin expressed by the cells, and a transient FOS mRNA induction followed by FOS protein still elevated after 24 h of illumination was revealed. Exposing the cells to darkness after light resulted in reduction of the response compared to exposure to light solely showing dependency on continuous light. Increasing irradiances of blue light (480 nm) up to 1011 quanta x cm−2 x s−1 elicited steep increases in FOS mRNA, while increases between 1012 and 5 x 1013 quanta x cm−2 x s−1 resulted in equally high FOS expression. The HEK‐hMel cells were used to characterize facets of melanopsin's light induced FOS response not approachable in vivo. Novel information such as dependency of the FOS response on both melanopsin amount and light intensity in addition to a detailed time‐course of both FOS mRNA and protein were revealed. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-09T05:05:51.846635-05:
      DOI: 10.1111/php.12298
       
  • Photophysics, Excited‐state Double‐Proton Transfer and
           Hydrogen‐bonding Properties of 5‐Deazaalloxazines
    • Authors: Dorota Prukala; Igor Khmelinskii, Jacek Koput, Mateusz Gierszewski, Tomasz Pędziński, Marek Sikorski
      Abstract: The photophysical properties of 5‐deazaalloxazine and 1,3‐dimethyl‐5‐deazaalloxazine were studied in different solvents. These compounds have higher values of fluorescence quantum yields and longer fluorescence lifetimes, compared to those obtained for their alloxazine analogs. Electronic structure and S0–Si transitions were investigated using the ab initio methods [MP2, CIS(D), EOM‐CCSD] with the correlation‐consistent basis sets. Also the time‐dependent density functional theory (TD‐DFT) has been employed. The lowest singlet excited states of 5‐deazaalloxazine and 1,3‐dimethyl‐5‐deazaalloxazine are predicted to have the π, π* character, whereas similar alloxazines have two close‐lying π, π* and n, π* transitions. Experimental steady‐state and time‐resolved spectral studies indicate formation of an isoalloxazinic excited state via excited‐state double‐proton transfer (ESDPT) catalyzed by an acetic acid molecule that forms a hydrogen bond complex with the 5‐deazaalloxazine molecule. Solvatochromism of both 5‐deazaalloxazine and its 1,3‐dimethyl substituted derivative was analyzed using the Kamlet–Taft scale and four‐parameter Catalán solvent scale. The most significant result of our studies is that the both scales show a strong influence of solvent acidity (hydrogen bond donating ability) on the emission properties of these compounds, indicating the importance of intermolecular solute–solvent hydrogen‐bonding interactions in their excited state. Photophysics of 5‐deazaalloxazine and its 1,3‐methyl substituted derivatives in different solvents indicate strong influence of solvent acidity on their emission properties. The experimental results are compared to the theoretical calculations on different level of theory. Excited‐state double‐proton transfer of 5‐deazaalloxazine in methylene chloride in the presence of acetic acid has been detected and studied.
      PubDate: 2014-06-05T06:04:23.508009-05:
      DOI: 10.1111/php.12289
       
  • Influence of Dye Content on the Conduction Band Edge of Titania in the
           Steam‐Treated Dye‐Dispersing Titania Electrodes
    • Authors: Rudi Agus Setiawan; Hiromasa Nishikiori, Nobuaki Tanaka, Tsuneo Fujii
      Abstract: The titania and dye‐dispersing titania electrodes were prepared by a nitric acid‐catalyzed sol‐gel process. The dye‐dispersing titania contains the dye molecules dispersed on the surface of the individual nanosized titania particles. The photo‐cyclic voltammetry (Photo‐CV) and photoelectric measurements of the dye‐dispersing titania electrodes were conducted in order to clarify the factors changing the conduction band edge of the titania and the open‐circuit voltage (Voc) of the electrodes. The remaining nitrate ions caused a negative shift of conduction band edge of the titania of the dye‐dispersing titania. The conduction band edge of the titania was shifted in a negative direction in the electrode containing a greater amount of the dye. These results are due to the adsorption of nitrate ions and the dye‐titania complex formation on the titania particle surface. The effect of the dye‐titania complex formation on the shift in the titania conduction band edge was greater than that of the adsorption of nitrate ions due to strong interaction between the dye and titania through the carboxylate and quinone‐like groups of the dye. The shift in the titania conduction band edge corresponded to the change in the Voc value. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-04T01:30:24.296136-05:
      DOI: 10.1111/php.12297
       
  • UVER dose received by golfers in winter, in Valencia
    • Authors: Gonzalo Gurrea Ysasi; Juan Carlos Moreno, Mª Antonia Serrano
      Abstract: This paper analyses UVER (Ultraviolet Erythematic Radiation) dose received by several golf players in winter in Valencia. Playing golf involves spending several hours outdoors because of the length of golf matches and training. Moreover, in Valencia there are many golf players coming from northern Europe, with a phototype very sensitive (I‐II). For that reason these people have an increasing risk while playing. This paper shows that harmful effects coming from UVER radiation may occur not only in summer time but also in winter, especially at these latitudes. VioSpor dosimeters have been used in order to develop this analysis over several golf players on January 2013 between 10:00h and 15:00h, local time. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-04T01:30:21.225555-05:
      DOI: 10.1111/php.12295
       
  • Photoexcited States of UV Absorbers, Benzophenone Derivatives
    • Authors: Ryo Kumasaka; Azusa Kikuchi, Mikio Yagi
      Pages: 727 - 733
      Abstract: The UV absorption, phosphorescence and phosphorescence‐excitation spectra of benzophenone (BP) derivatives used as organic UV absorbers have been observed in rigid solutions at 77 K. The triplet–triplet absorption spectra have been observed in acetonitrile at room temperature. The BP derivatives studied are 2,2′,4,4′‐tetrahydroxybenzophenone (BP‐2), 2‐hydroxy‐4‐methoxybenzophenone (BP‐3), 2,2′‐dihydroxy‐4,4′‐dimethoxybenzophenone (BP‐6), 5‐chloro‐2‐hydroxybenzophenone (BP‐7) and 2‐hydroxy‐4‐n‐octyloxybenzophenone (BP‐12). The energy levels and lifetimes of the lowest excited triplet (T1) states of these BP derivatives were determined from the first peak of phosphorescence. The time‐resolved near‐IR emission spectrum of singlet oxygen generated by photosensitization with BP‐7 was observed in acetonitrile at room temperature. BP‐2, BP‐3, BP‐6 and BP‐12 show photoinduced phosphorescence enhancement in ethanol at 77 K. The possible mechanism of the observed phosphorescence enhancement is discussed. The T1 states of 2‐hydroxy‐5‐methylbenzophenone, 4‐methoxybenzophenone and 2,4′‐dimethoxybenzophenone have been studied for comparison. The energy levels and lifetimes of the lowest excited triplet states of benzophenone (BP) derivatives, BP‐2, BP‐3, BP‐6, BP‐7 and BP‐12, used as organic UV absorbers in cosmetic sunscreens were determined in rigid solutions at 77 K. The time‐resolved near‐IR emission spectrum of singlet oxygen generated by photosensitization with BP‐7 was observed in acetonitrile at room temperature. BP‐2, BP‐3, BP‐6 and BP‐12 show photoinduced phosphorescence enhancement in ethanol at 77 K.
      PubDate: 2014-03-07T00:42:48.386498-05:
      DOI: 10.1111/php.12257
       
  • Photophysics of a Coumarin in Different Solvents: Use of Different
           Solvatochromic Models
    • Authors: Banibrata Maity; Aninda Chatterjee, Debabrata Seth
      Pages: 734 - 746
      Abstract: This study reported the photophysics of 7‐(diethylamino)coumarin‐3‐carboxylic acid N‐succinimidyl ester (7‐DCCAE) in different neat solvents of varying polarity using steady‐state absorption, fluorescence emission and picosecond time‐resolved spectroscopy. In nonpolar solvents, the dye molecule predominantly exists in nonpolar structure and exhibits very low value of nonradiative decay rate constant (knr), demonstrating the emission takes place from S1‐LE to S0 ground state. The fluorescence quantum yields, lifetime values of 7‐DCCAE in different solvents are rationalized on the basis of intramolecular charge transfer (ICT) followed by twisted intramolecular charge transfer state formation (TICT) as well as specific solute–solvent interactions. Several solvatochromic models (such as Lippert, Dimroth, Kamlet–Taft, Catalán 3P and Catalán 4P models) were used to analyze the solvatochromic shift of 7‐DCCAE in different solvents. The different empirical models show that the observed results are better correlate for nonchlorinated solvents and provide statistically significant best‐fit result. A comparison was done between comparatively new solvatochromic model (Catalán 3P and Catalán 4P model) with Kamlet–Taft model. The ground state structure of the said molecule was optimized by using Density Functional Theory (DFT). This study demonstrated the photophysics of 7‐(diethylamino)coumarin‐3‐carboxylic acid N‐succinimidyl ester (7‐DCCAE) in the presence of different neat solvents. Different empirical solvatochromic models were used to analyze the solvatochromic shift of 7‐DCCAE in different solvents.
      PubDate: 2014-03-18T00:35:19.946698-05:
      DOI: 10.1111/php.12258
       
  • Influences of Acid on Molecular Forms of Fluorescein and Photoinduced
           Electron Transfer in Fluorescein‐Dispersing Sol–Gel Titania
           Films
    • Authors: Hiromasa Nishikiori; Rudi Agus Setiawan, Kyohei Miyashita, Katsuya Teshima, Tsuneo Fujii
      Pages: 747 - 759
      Abstract: Fluorescein‐dispersing titania gel films were prepared by the acid‐catalyzed sol–gel reaction using a titanium alkoxide solution containing fluorescein. The molecular forms of fluorescein in the films, depending on its acid–base equilibria, and the complex formation and photoinduced electron transfer process between the dye and titania surface were investigated by fluorescence and photoelectric measurements. The titanium species were coordinated to the carboxylate and phenolate‐like groups of the fluorescein species. The quantum efficiencies of the fluorescence quenching and photoelectric conversion were higher upon excitation of the dianion species interacting with the titania, i.e. the dye–titania complex. This result indicated that the dianion form was the most favorable for formation of the dye–titania complex exhibiting the highest electron transfer efficiency. Using nitric acid as the catalyst, the titania surface bonded to the fluorescein instead of the adsorbed nitrate ion during the steam treatment. The dye–titania complex formation played an important role in the electron injection from the dye to the titania conduction band. Fluorescein‐dispersing titania gel films were prepared by the acid‐catalyzed sol–gel reaction using a titanium alkoxide solution containing fluorescein. The titanium species were coordinated to the carboxylate and phenolate‐like groups of the fluorescein species. The quantum efficiencies of the fluorescence quenching and photoelectric conversion were higher upon excitation of the dianion species interacting with the titania, i.e. the dye–titania complex. Using nitric acid as the catalyst, the titania surface bonded to the fluorescein instead of the adsorbed nitrate ion during the steam treatment. The complex formation played an important role in the electron injection from the dye to the titania.
      PubDate: 2014-02-23T03:27:37.404841-05:
      DOI: 10.1111/php.12254
       
  • Photodecomposition of Chloroform Catalyzed by Unmodified MCM‐41
           Mesoporous Silica
    • Authors: Laura A. Peña; Alissa M. Chan, Larissa R. Cohen, Karen Hou, Brent M. Harvey, Patrick E. Hoggard
      Pages: 760 - 766
      Abstract: Unactivated MCM‐41 mesoporous silica catalyzes the photodecomposition of chloroform to phosgene and hydrogen chloride under near‐UV (λ > 360 nm) irradiation. The rate of photodecomposition increases toward an asymptotic limit as the O2 partial pressure is increased. Deuterochloroform does not decompose under the same experimental conditions. Low concentrations of both cyclohexane and ethanol quench the photodecomposition, whereas water, up to its solubility limit, does not. Dissolved tetraalkylammonium salts suppress photodecomposition. The data are consistent with a mechanism in which light absorption by an SiO2 defect yields an electron‐deficient oxygen atom, which then abstracts hydrogen from chloroform. The resulting CCl3 radicals react with oxygen to form a peroxy radical that decomposes, eventually yielding phosgene and hydrogen chloride. Unmodified MCM‐41 silica catalyzes the photodecomposition of chloroform under near‐UV irradiation. It is proposed that decomposition is initiated through hydrogen abstraction from chloroform at a photoactive SiO2 defect site.
      PubDate: 2014-02-15T08:57:58.64308-05:0
      DOI: 10.1111/php.12245
       
  • The Number of Accumulated Photons and the Quality of Stimulated Emission
           Depletion Lifetime Images
    • Authors: Aleem Syed; Michael D. Lesoine, Ujjal Bhattacharjee, Jacob W. Petrich, Emily A. Smith
      Pages: 767 - 772
      Abstract: Time binning is used to increase the number of photon counts in the peak channel of stimulated emission depletion fluorescence lifetime decay curves to determine how it affects the resulting lifetime image. The fluorescence lifetime of the fluorophore, Alexa Fluor 594 phalloidin, bound to F‐actin is probed in cultured S2 cells at a spatial resolution of ~40 nm. This corresponds to a 10‐fold smaller probe volume compared to confocal imaging, and a reduced number of photons contributing to the signal. Pixel‐by‐pixel fluorescence lifetime measurements and error analysis show that an average of 40 ± 30 photon counts in the peak channel with a signal‐to‐noise ratio of 20 is enough to calculate a reliable fluorescence lifetime from a single exponential fluorescence decay. No heterogeneity in the actin cytoskeleton in different regions of the cultured cells was measured in the 40–400 nm spatial regime. Photon counts in the peak channel of stimulated emission depletion fluorescence lifetime decay curves are increased by time binning without affecting the spatial resolution of the measurements. The fluorescence lifetime of Alexa Fluor 594 phalloidin bound to F‐actin is probed in cultured cells at a spatial resolution 10‐fold better compared to confocal imaging. Pixel‐by‐pixel fluorescence lifetime measurements and error analysis show that an average of 40 ± 30 counts in the peak channel with a signal‐to‐noise ratio of 20 is enough to calculate a reliable fluorescence lifetime from a single exponential fluorescence decay.
      PubDate: 2014-03-03T03:59:51.442193-05:
      DOI: 10.1111/php.12248
       
  • Bistable Retinal Schiff Base Photodynamics of Histidine Kinase Rhodopsin
           HKR1 from Chlamydomonas reinhardtii
    • Authors: Alfons Penzkofer; Meike Luck, Tilo Mathes, Peter Hegemann
      Pages: 773 - 785
      Abstract: The photodynamics of the recombinant rhodopsin fragment of the histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii was studied by absorption and fluorescence spectroscopy. The retinal cofactor of HKR1 exists in two Schiff base forms RetA and RetB. RetA is the deprotonated 13‐cis‐retinal Schiff base (RSB) absorbing in the UVA spectral region. RetB is the protonated all‐trans RSB absorbing in the blue spectral region. Blue light exposure converts RetB fully to RetA. UVA light exposure converts RetA to RetB and RetB to RetA giving a mixture determined by their absorption cross sections and their conversion efficiencies. The quantum efficiencies of conversion of RetA to RetB and RetB to RetA were determined to be 0.096 ± 0.005 and 0.405 ± 0.01 respectively. In the dark thermal equilibration between RetA and RetB with dominant RetA content occurred with a time constant of about 3 days at room temperature. The fluorescence emission behavior of RetA and RetB was studied, and fluorescence quantum yields of ϕF(RetA) = 0.00117 and ϕF(RetB) = 9.4 × 10−5 were determined. Reaction coordinate schemes of the photodynamics are developed. In HKR1 two thermally stable retinal Schiff base (RSB) forms RetA and RetB exist. RetA is deprotonated 13‐cis, 15‐anti RSB absorbing in the UV. RetB is protonated all‐trans 15‐anti and 15‐syn RSB absorbing blue light. RetB is blue‐light convertible to RetA with quantum efficiency of 0.4. RetA is UVA light convertible to RetB with quantum efficiency of 0.1.
      PubDate: 2014-03-08T01:55:35.235511-05:
      DOI: 10.1111/php.12246
       
  • Tyrosine 263 in Cyanobacterial Phytochrome Cph1 Optimizes Photochemistry
           at the prelumi‐R→lumi‐R Step
    • Authors: Vitaly Sineshchekov; Joel Mailliet, Georgios Psakis, Kathleen Feilke, Jakub Kopycki, Mathias Zeidler, Lars‐Oliver Essen, Jon Hughes
      Pages: 786 - 795
      Abstract: We report a low‐temperature fluorescence spectroscopy study of the PAS‐GAF‐PHY sensory module of Cph1 phytochrome, its Y263F mutant (both with known 3D structures) as well as Y263H and Y263S to connect their photochemical parameters with intramolecular interactions. None of the holoproteins showed photochemical activity at low temperature, and the activation barriers for the Pr→lumi‐R photoreaction (2.5–3.1 kJ mol−1) and fluorescence quantum yields (0.29–0.42) were similar. The effect of the mutations on Pr→Pfr photoconversion efficiency (ΦPr→Pfr) was observed primarily at the prelumi‐R S0 bifurcation point corresponding to the conical intersection of the energy surfaces at which the molecule relaxes to form lumi‐R or Pr, lowering ΦPr→Pfr from 0.13 in the wild type to 0.05–0.07 in the mutants. We suggest that the Ea activation barrier in the Pr* S1 excited state might correspond to the D‐ring (C19) carbonyl – H290 hydrogen bond or possibly to the hindrance caused by the C131/C171 methyl groups of the C and D rings. The critical role of the tyrosine hydroxyl group can be at the prelumi‐R bifurcation point to optimize the yield of the photoprocess and energy storage in the form of lumi‐R for subsequent rearrangement processes culminating in Pfr formation. Y263 in Cph1 is perfectly conserved among phytochromes, even though mutations at that site seemed to be innocuous. Here we show that, on the contrary, tyrosine is important in optimizing photochemistry toward lumi‐R at the of S0/S1 conical intersection (prelumi‐R). A possible structure of the prelumi‐R phantom state is shown here.
      PubDate: 2014-03-28T00:13:13.315141-05:
      DOI: 10.1111/php.12263
       
  • The Effect of Photodynamic Action on Leakage of Ions Through Liposomal
           Membranes that Contain Oxidatively Modified Lipids
    • Authors: Shany Ytzhak; Benjamin Ehrenberg
      Pages: 796 - 800
      Abstract: Singlet oxygen, created in photosensitization, peroxidizes unsaturated fatty acids of the membrane's lipids. This generates alcoholic or aldehyde groups at double bonds' breakage points. In a previous study, we examined the leakage of a K+‐induced cross‐membrane electric potential of liposomes that undergo photosensitization. The question remains to what extent peroxidized lipids can compromise the stability of the membrane. In this study, we studied the effect of the oxidatively modified lipids PGPC and ALDOPC in the membrane on its stability, by monitoring the membrane electric potential with the potentiometric dye DiSC2(5). As the content of the modified lipids increases the membrane becomes less stable, and even at just 2% of the modified lipids the membrane's integrity is affected, in respect to the leakage of ions through it. When the liposomes that contain the modified lipids undergo photosensitization by hematoporphyrin, the lipid bilayer becomes even more unstable and passage of ions is accelerated. We conclude that the existence of lipids with a shortened fatty acid that is terminated by a carboxylic acid or an aldehyde and more so when photosensitized damage occurs to unsaturated fatty acids in lecithin, add up to a critical alteration of the membrane, which becomes leaky to ions. We measured the integrity of the liposomal membrane when it includes oxidatively modified lipids and when it is exposed to photodynamic action by photosensitization with hematoporphyrin. We demonstrate that the photodynamic process, in which unsaturated lipids of natural lecithin are damaged, is not causing the lipid bilayer to leak, but it strongly accelerates the leakage of ions if a very small fraction of the natural lipids are replaced by the modified lipids.
      PubDate: 2014-03-25T04:16:38.332518-05:
      DOI: 10.1111/php.12266
       
  • Membrane Damage Efficiency of Phenothiazinium Photosensitizers
    • Authors: Isabel O. L. Bacellar; Christiane Pavani, Elisa M. Sales, Rosangela Itri, Mark Wainwright, Mauricio S. Baptista
      Pages: 801 - 813
      Abstract: Structure–activity relationships have been widely reported for porphyrin and phthalocyanine photosensitizers, but not for phenothiazinium derivatives. Here, four phenothiazinium salts (methylene blue, toluidine blue O, 1,9‐dimethyl methylene blue and the pentacyclic derivative DO15) were used to investigate how the ability to damage membranes is affected by membrane/solution partition, photophysical properties and tendency to aggregation of the photosensitizer. These two latter aspects were studied both in isotropic solutions and in membranes. Membrane damage was assessed by leakage of a fluorescent probe entrapped in liposomes and by generation of thiobarbituric acid‐reactive species (TBARS), while structural changes at the lipid bilayer were detected by small‐angle X‐ray scattering. We observed that all compounds had similar singlet‐oxygen quantum yields in ethanol, but only the photosensitizers that had higher membrane/solution partition (1,9‐dimethyl methylene blue and DO15, the latter having the higher value) could permeabilize the lipid bilayer. Moreover, of these two photosensitizers, only DO15 altered membrane structure, a result that was attributed to its destabilization of higher order aggregates, generation of higher amounts of singlet oxygen within the membranes and effective electron‐transfer reaction within its dimers. We concluded that membrane‐based protocols can provide a better insight on the photodynamic efficiency of the photosensitizer. Structure–activity relationships were investigated for a series of phenothiazinium photosensitizers (methylene blue, toluidine blue O, 1,9‐dimethyl methylene blue and DO15). We compared the ability of these compounds to damage membranes by quantifying the efficiency of liposome permeabilization, which was correlated with singlet‐oxygen generation within the membranes, membrane/solution partition and tendency of aggregation of the photosensitizers. We concluded that membrane‐based protocols can provide a better understanding on the photodynamic efficiency of the photosensitizer.
      PubDate: 2014-03-26T07:14:12.941057-05:
      DOI: 10.1111/php.12264
       
  • Antioxidative Activities of Algal Keto Carotenoids Acting as Antioxidative
           Protectants in the Chloroplast
    • Authors: Michael Dambeck; Gerhard Sandmann
      Pages: 814 - 819
      Abstract: Very diverse carotenoid structures exist in the photosynthesis apparatus of different algae. Among them, the keto derivatives are regarded the most antioxidative. Therefore, four different keto carotenoids, peridinin, fucoxanthin, siphonaxanthin and astaxanthin fatty acid monoesters, were isolated and purified from Amphidinium carterae, Phaeodactylum tricornutum, Caulerpa taxifolia and Haematococcus pluvialis, respectively. The carotenoids were assayed as inhibitors of photosensitizer initiated reactions or scavengers of radicals in the early events generating reactive oxygen species as starters for peroxidation and as protectants against the whole reaction chain finally leading to lipid peroxidation. These in vitro studies demonstrated the substantial antioxidative properties as indicated by the IC50 values of all four keto carotenoids with superior protection by astaxanthin fatty acid monoesters which were as effective as free astaxanthin and of peridinin against radicals. As an example, the in vivo relevance of fucoxanthin for protection of photosynthesis from excess light and from peroxidative agents was evaluated with intact cells. Cultures of P. tricornutum with decreased fucoxanthin content generated by inhibitor treatment were exposed to strong light or cumene hydroperoxyde. In each case, oxidation of chlorophyll as marker for damaging of the photosynthesis apparatus was less severe when the fucoxanthin was at maximum level. Carotenoids and especially their keto derivatives are known for their antioxidative potential. Therefore the keto carotenoids peridinin, siphonaxanthin, fucoxanthin and astaxanthin mono fatty acid ester were isolated from different algae. They were assayed for their antioxidative properties as quenchers of singlet oxygen and oxo radicals and their potential was determined to protect against singlet oxygen‐ or radical‐mediated peroxidation reactions.
      PubDate: 2014-02-26T06:53:24.924557-05:
      DOI: 10.1111/php.12249
       
  • Analysis of Photoexcitation Energy Dependence in the Photoluminescence of
           Firefly Luciferin
    • Authors: Miyabi Hiyama; Hidefumi Akiyama, Toshimitsu Mochizuki, Kenta Yamada, Nobuaki Koga
      Pages: 820 - 828
      Abstract: The whole pathways for photoluminescence, which include absorption, relaxation and emission, of firefly luciferin in aqueous solutions of different pH values with different photoexcitation energies were theoretically investigated by considering protonation/deprotonation. It is experimentally known that the color of fluorescence changes from green to red with a decrease in the photoexcitation energy. We confirmed with the theoretical analysis that the peak energy shift in the fluorescence spectra with varying photoenergies is due to a change in photoluminescence pathway. When the photoexcitation energy is decreased, the red emission from a monoanion form of firefly luciferin with carboxylate and phenolate groups and N‐protonated thiazoline ring occurs irrespective of the pH values. However, because the species abundant in the solution and those excited by the photon depend on the solution pH, the pathway leading to the monoanion form changes with the solution pH. By considering protonation/deprotonation, the whole pathways for photoluminescence of firefly luciferin in aqueous solutions of different pH values with different photoexcitation energies were theoretically investigated.
      PubDate: 2014-02-15T09:00:32.94203-05:0
      DOI: 10.1111/php.12243
       
  • Quantitative and in situ Detection of Oxidatively Generated DNA Damage
           8,5′‐Cyclo‐2′‐Deoxyadenosine Using an
           Immunoassay with a Novel Monoclonal Antibody
    • Authors: Takaaki Iwamoto; Philip J. Brooks, Tomohisa Nishiwaki, Kazuki Nishimura, Nobuhiko Kobayashi, Shigeki Sugiura, Toshio Mori
      Pages: 829 - 836
      Abstract: Xeroderma pigmentosum (XP) is a genetic disorder associated with defects in nucleotide excision repair, which eliminates a wide variety of helix‐distorting types of DNA damage including sunlight‐induced pyrimidine dimers. In addition to skin disease, approximately 30% of XP patients develop progressive neurological disease, which has been hypothesized to be associated with the accumulation of a particular type of oxidatively generated DNA damage called purine 8,5′‐cyclo‐2′‐deoxynucleosides (purine cyclonucleosides). However, there are no currently available methods to detect purine cyclonucleosides in DNA without the need for DNA hydrolysis. In this study, we generated a novel monoclonal antibody (CdA‐1) specific for purine cyclonucleosides in single‐stranded DNA that recognizes 8,5′‐cyclo‐2′‐deoxyadenosine (cyclo‐dA). An immunoassay using CdA‐1 revealed a linear dose response between known amounts of cyclo‐dA in oligonucleotides and the antibody binding to them. The quantitative immunoassay revealed that treatment with Fenton‐type reagents (CuCl2/H2O2/ascorbate) efficiently produces cyclo‐dA in DNA in a dose‐dependent manner. Moreover, immunofluorescent analysis using CdA‐1 enabled the visualization of cyclo‐dA in human osteosarcoma cells, which had been transfected with oligonucleotides containing cyclo‐dA. Thus, the CdA‐1 antibody is a valuable tool for the detection and quantification of cyclo‐dA in DNA, and may be useful for characterizing the mechanism(s) underlying the development of XP neurological disease. Xeroderma pigmentosum (XP) is a genetic disorder associated with defects in nucleotide excision repair, which eliminates a wide variety of helix‐distorting DNA damage including sunlight‐induced pyrimidine dimers. In addition to skin disease, approximately 30% of XP patients develop progressive neurological disease, which has been hypothesized to be associated with the accumulation of oxidatively generated DNA damage called purine cyclonucleosides. In this study, we generated a novel monoclonal antibody (CdA‐1) specific for purine cyclonucleosides in DNA that recognizes 8,5′‐cyclo‐2′‐deoxyadenosine (cyclo‐dA). An immunofluorescent analysis using CdA‐1 enabled the visualization of cyclo‐dA (green dots) in human osteosarcoma cells, which had been transfected with oligonucleotides containing 5′S‐cyclo‐dA.
      PubDate: 2014-02-23T03:27:25.885149-05:
      DOI: 10.1111/php.12239
       
  • Bystander Effect Induced by UVC Radiation in Chinese hamster V79 cells
    • Authors: Shengwen Wu; Cuihong Jin, Xiaobo Lu, Jinghua Yang, Qiufang Liu, Ming Qi, Shuai Lu, Lifeng Zhang, Yuan Cai
      Pages: 837 - 844
      Abstract: In past decades, researches on radiation‐induced bystander effect mainly focused on ionizing radiation such as α‐particle, β‐particle, X‐ray and γ‐ray. But few researches have been conducted on the ability of ultraviolet (UV) radiation‐induced bystander effect, and knowledge of UVC‐induced bystander effect is far limited. Here, we adopted medium transfer experiment to detect whether UVC could cause bystander effect in Chinese hamster V79 cells. We determined the cell viability, apoptosis rate, chromosome aberration and ultrastructure changes, respectively. Our results showed that: (1) the viability of UVC‐irradiated V79 cells declined significantly with the dosage of UVC; (2) similar to the irradiated cells, the main death type of bystander cells cultured in irradiation conditioned medium (ICMs) was also apoptosis; (3) soluble factors secreted by UVC‐irradiated cells could induce bystander effect in V79 cells; (4) cells treated with 4 h ICM collected from 90 mJ cm−2 UVC‐irradiated cells displayed the strongest response. Our data revealed that UVC could cause bystander effect through the medium soluble factors excreted from irradiated cells and this bystander effect was a novel quantitative and kinetic response. These findings might provide a foundation to further explore the exact soluble bystander factors and detailed mechanism underlying UVC‐induced bystander effect. This study showed that UVC radiation induced some damage in irradiated V79 cells, which might initiate apoptosis progress when damage couldn't be repaired. The UVC‐irradiated apoptotic cells released gradually some soluble factors into irradiated conditioned medium (ICMs) which finally induced bystander effect in unirradiated V79 cells.
      PubDate: 2014-03-05T02:04:30.302866-05:
      DOI: 10.1111/php.12255
       
  • Phosphorylation of Histone H2AX Generated by Linear Alkylbenzene
           Sulfonates and its Suppression by UVB Exposure
    • Authors: Toru Kubota; Tatsushi Toyooka, Xiaoxu Zhao, Yuko Ibuki
      Pages: 845 - 852
      Abstract: We previously demonstrated that the nonionic surfactants, nonylphenol polyethoxylates (NPEOs) induced the phosphorylation of histone H2AX (γ‐H2AX), accompanied by DNA double‐strand breaks (DSBs), and that exposure to ultraviolet (UV) degraded NPEOs, which sometimes enhanced their DNA‐damaging ability. In this study, we showed that linear alkylbenzene sulfonates (LAS), general anion surfactants, also generated DSBs with γ‐H2AX, and this ability was attenuated by UVB exposure. In the human breast adenocarcinoma cell line, MCF‐7, γ‐H2AX was generated in a dose‐dependent manner immediately after cells were treated with LAS, and this was attributed to the formation of DSBs and was independent of cell cycle phases. The ability to generate γ‐H2AX was markedly reduced in LAS exposed to UVB. HPLC analysis revealed that LAS were a mixture of various alkyl chain lengths, the peaks of which were detected at individual retention times. UVB evenly decreased all peaks of LAS, without migration of peaks to other retention times, which indicated that UVB may degrade the benzene ring of LAS, but did not shorten the alkyl chains. UVB is an important environmental factor in the degradation of LAS exhibiting the ability to induce DSBs, the most serious type of DNA damage. Linear alkylbenzene sulfonates (LAS), general anion surfactants, generated DNA double‐strand breaks (DSBs) with phosphorylation of histone H2AX (γ‐H2AX). The ability to generate γ‐H2AX was markedly reduced in LAS exposed to UVB. HPLC analysis revealed that UVB evenly decreased all peaks of LAS, without migration of peaks to other retention times, which indicated that UVB may degrade the benzene ring of LAS, but did not shorten the alkyl chains. UVB is an important environmental factor in the degradation of LAS exhibiting the ability to induce DSBs, the most serious type of DNA damage.
      PubDate: 2014-03-26T07:14:15.44248-05:0
      DOI: 10.1111/php.12268
       
  • Effects of white light‐emitting diode (LED) light exposure with
           different Correlated Color Temperatures (CCTs) on human lens epithelial
           cells in culture
    • Authors: Chen Xie; Xiuyi Li, Jianping Tong, Yangshun Gu, Ye Shen
      Pages: 853 - 859
      Abstract: Cataract is the major cause for legal blindness in the world. Oxidative stress on the lens epithelial cells (hLECs) is the most important factor in cataract formation. Cumulative light‐exposure from widely used light‐emitting diodes (LEDs) may pose a potential oxidative threat to the lens epithelium, due to the high‐energy blue light component in the white‐light emission from diodes. In the interest of perfecting biosafety standards for LED domestic lighting, this study analyzed the photobiological effect of white LED light with different correlated color temperatures (CCTs) on cultured hLECs. The hLECs were cultured and cumulatively exposed to multichromatic white LED light with CCTs of 2954, 5624, and 7378 K. Cell viability of hLECs was measured by Cell Counting Kit‐8 (CCK‐8) assay. DNA damage was determined by alkaline comet assay. Intracellular reactive oxygen species (ROS) generation, cell cycle, and apoptosis were quantified by flow cytometry. Compared with 2954 and 5624 K LED light, LED light having a CCT of 7378 K caused overproduction of intracellular ROS and severe DNA damage, which triggered G2/M arrest and apoptosis. These results indicate that white LEDs with a high CCT could cause significant photobiological damage to hLECs. Oxidative stress on the lens epithelial cells (hLECs) is the most important factor in cataract formation. Cumulative light exposure from widely used light‐emitting diodes (LEDs) may pose a potential oxidative threat to the lens epithelium, due to the high‐energy blue light component in the white‐light emission from diodes. LED light having a CCT of 7378 K caused overproduction of intracellular ROS and severe cellular damage, which indicate that white LEDs with a high CCT could cause significant photobiological damage to hLECs and detailed industrial standards for this new artificial light source should be determined for the sake of ocular safety.
      PubDate: 2014-02-25T05:53:10.923291-05:
      DOI: 10.1111/php.12250
       
  • Dimerization of Resveratrol Induced by Red Light and Its Synergistic
           Analgesic Effects with Cobra Neurotoxin
    • Authors: Yong Ye; Fei Fang, Yue Li
      Pages: 860 - 866
      Abstract: Resveratrol polymer has better effects than monomer in some aspects as reported, but most of synthetic methods acquire severe conditions and no analgesic effects are investigated. A novel method is found to synthesize resveratrol polymer by excitation of photosensitizer pheophorbide at red light of 630 nm. The polymer was analyzed by fluorescence spectra and HPLC, further isolated by preparative liquid chromatography and identified as a resveratrol dimer by MS and NMR. Analgesic effects were measured by acetic acid writhing and hot‐plate test in mice. The resveratrol dimer has the stronger analgesic effects than monomer, and drug combination of the dimer and cobra neurotoxin enhances and prolongs analgesic effects, suggesting the synergistic action. Simulation of molecular interaction reveals that the dimer spontaneously binds to cobra neurotoxin and makes a complex substance. The dimer can interact with cyclooxygenase‐2, μ receptor and nicotine receptor, the synergistic analgesic effects of the complex are attributed to its multiple targets role. The combination of resveratrol dimer and cobra neurotoxin may make up for their deficiencies in analgesic effects, and has prospects in clinical use. A new synthetic method is designed for resveratrol dimer, which is induced by the excitation of photosensitizer pheophorbide at red light of 630 nm, the mechanism is illustrated. The dimer interacts with cobra neurotoxin and forms a complex substance, which shows significant synergistic analgesic effects after combined administration to mice. The dimer has multiple targets, and its combination with cobra neurotoxin may make up for their deficiencies in analgesic effects suggesting good prospects in clinical use.
      PubDate: 2014-03-15T00:21:21.266073-05:
      DOI: 10.1111/php.12262
       
  • Hypericin as a Marker for Determination of Myocardial Viability in a Rat
           Model of Myocardial Infarction
    • Authors: Cuihua Jiang; Yue Li, Xiao Jiang, Nan Yao, Meng Gao, Xueli Zhang, Junying Wang, Xiaoning Wang, Ziping Sun, Jian Zhang, Yicheng Ni
      Pages: 867 - 872
      Abstract: The aim of this study was to investigate the necrosis‐avid agent hypericin as a potential indicator for determination of myocardial infarction (MI). Male Sprague‐Dawley rats (n = 30) weighing 350 ± 20 g were subjected to acute reperfused MI. Animals were divided into four groups (n = 6), in which hypericin was intravenously injected at 0, 1, 2 and 5 mg kg−1 respectively. One day after injection, rats were euthanized with their hearts excised for qualitative and quantitative studies by means of microscopic fluorescence examination to decide the dosage of hypericin. Another group was injected with hypericin at the decided dose and evaluated by fluorescence macroscopy in colocalization with triphenyltetrazoliumchloride (TTC) and histomorphology. Infarct‐to‐normal contrast ratio and relative infarct size were quantified. Hypericin‐induced red fluorescence was significantly brighter in necrotic than in viable myocardium as proven by a six times higher mean fluorescence density. Mean MI area was 35.66 ± 22.88% by hypericin fluorescence and 32.73 ± 21.98% by TTC staining (R2 = 0.9803). Global MI‐volume was 34.56 ± 21.07% by hypericin and 35.11 ± 20.47% by TTC staining (R2 = 0.9933). The results confirm that hypericin specifically labeled necrosis, and enhanced the imaging contrast between the infarcted and normal myocardium, suggesting its potential applications for the assessment of myocardial viability. The aim of this study was to investigate the necrosis avid agent hypericin as a potential indicator for determination of myocardial infarction. Animals were challenged with different doses of hypericin (0, 1, 2, and 5 mg kg−1) after an experimental myocardial infarction. Infarct‐to‐normal contrast ratio and relative infarct size were evaluated by fluorescence macroscopy in colocalization with triphenyltetrazoliumchloride and histomorphology. Results confirm that hypericin specifically labeled necrosis, and enhanced the imaging contrast between the infarcted and normal myocardium, suggesting its potential applications for the assessment of myocardial viability.
      PubDate: 2014-02-26T06:50:06.896073-05:
      DOI: 10.1111/php.12247
       
  • Efficacy of Low‐Dose Ultraviolet A‐1 Phototherapy for
           Parapsoriasis/Early‐Stage Mycosis Fungoides
    • Authors: Kenan Aydogan; Serkan Yazici, Saduman Balaban Adim, Isil Tilki Gunay, Ferah Budak, Hayriye Saricaoglu, Sukran Tunali, Emel Bulbul Baskan
      Pages: 873 - 877
      Abstract: Mycosis fungoides (MF) and parapsoriasis (PP) are major dermatologic conditions for which phototherapy continues to be a successful and valuable treatment option. UVA‐1 phototherapy is effective in the management of cutaneous T‐cell mediated diseases. The aim of the study was to evaluate the efficacy and safety of low‐dose UVA‐1 phototherapy for the management of PP/early‐stage MF. A total of 30 patients, diagnosed with MF (n:19) or PP (n:11) were enrolled to the study. All patients were managed with low‐dose UVA‐1 (20 or 30 J cm−2). Response was assessed clinically and immunohistochemically. UVA‐1 treatment led to clinical and histological complete remission (CR) in 11 of 19 MF patients (57.9%), partial remission (PR) in three of 19 (15.8%), after a mean cumulative dose of 1665 (range, 860–3120) J cm−2 and mean number of 73 exposure (range, 43–107) sessions. Five patients with PP (45.5%) showed CR, and PR was observed in six patients with PP (54.5%) after a mean cumulative dose of 1723 (range, 1060–3030) J cm−2 and mean number of 74 exposure (range, 53–101) sessions. We conclude that low‐dose UVA‐1 therapy seems to be an effective, safe, and well‐tolerated treatment option for patients with PP/early‐stage MF. Skin‐directed therapies are currently available treatment options for plaque type PP/early‐stage MF with some limitations, and management of the diseases is still challenging. Ultraviolet A‐1 (340–400 nm) phototherapy was first described in 1978 and it has became a valuable treatment for sclerotic and T‐cell mediated diseases, more deeply penetrates than UVB. This study showed that Low‐dose UVA‐1 therapy seems to be a safe and effective alternative to other therapeutic options in patients with PP/early‐stage MF who do not tolerate or respond to PUVA and UVB therapy, without systemic effect.
      PubDate: 2014-03-05T02:04:26.326034-05:
      DOI: 10.1111/php.12253
       
  • Measurement of Intracellular Oxygen Concentration During Photodynamic
           Therapy in vitro
    • Authors: Mark A. Weston; Michael S. Patterson
      Pages: 878 - 888
      Abstract: A technique is introduced that monitors the depletion of intracellular ground state oxygen concentration ([3O2]) during photodynamic therapy of Mat‐LyLu cell monolayers and cell suspensions. The photosensitizer Pd(II) meso‐tetra(4‐carboxyphenyl)porphine (PdT790) is used to manipulate and indicate intracellular [3O2] in both of the in vitro models. The Stern–Volmer relationship for PdT790 phosphorescence was characterized in suspensions by flowing nitrogen over the suspension while short pulses of 405 nm light were used to excite the sensitizer. The bleaching of sensitizer and the oxygen consumption rate were also measured during continuous exposure of the cell suspension to the 405 nm laser. Photodynamic therapy (PDT) was conducted in both cell suspensions and in cell monolayers under different treatment conditions while the phosphorescence signal was acquired. The intracellular [3O2] during PDT was calculated by using the measured Stern–Volmer relationship and correcting for sensitizer photobleaching. In addition, the amount of oxygen that was consumed during the treatments was calculated. It was found that even at large oxygen consumption rates, cells remain well oxygenated during PDT of cell suspensions. For monolayer treatments, it was found that intracellular [3O2] is rapidly depleted over the course of PDT. A novel technique is described that measures the intracellular ground state oxygen concentration ([3O2]) during photodynamic therapy of cell monolayers and cell suspensions. The photosensitizer Pd(II) meso‐tetra(4‐carboxyphenyl)porphine (PdT790) is used to deplete the cells of 3O2 by photodynamic action while simultaneously monitoring the intracellular [3O2]. The intracellular [3O2] is calculated using the steady‐state phosphorescence signal emitted by PdT790 during treatment. It was found that cells remain well oxygenated during PDT of cell suspensions, while for monolayer treatments intracellular [3O2] is rapidly reduced.
      PubDate: 2014-03-14T17:28:31.884701-05:
      DOI: 10.1111/php.12256
       
  • Enhanced Efficacy of Photodynamic Therapy via a Sequential Targeting
           Protocol
    • Authors: David Kessel; John J. Reiners
      Pages: 889 - 895
      Abstract: This study was designed to examine determinants of the discovery that low‐dose lysosomal photodamage (lyso‐PDT) could potentiate the efficacy of subsequent low‐dose mitochondrial photodamage (mito‐PDT). The chlorin NPe6 and the benzoporphyrin derivative (BPD) were used to separately target lysosomes and mitochondria, respectively, in murine hepatoma cells. Lyso‐PDT (LD5 conditions) followed by mito‐PDT (LD15 conditions) enhanced the loss of the mitochondrial membrane potential, activation of procaspases‐3/7 and photokilling. Reversing the sequence was less effective. The optimal sequence did not enhance reactive oxygen species formation above that obtained with low‐dose mito‐PDT. In contrast, alkalinization of lysosomes with bafilomycin also enhanced low‐dose mito‐PDT photokilling, but via a different pathway. This involves redistribution of iron from lysosomes to mitochondria leading to enhanced hydroxyl radical formation, effects not observed after the sequential procedure. Moreover, Ru360, an inhibitor of mitochondrial calcium and iron uptake, partially suppressed the ability of bafilomycin to enhance mito‐PDT photokilling without affecting the enhanced efficacy of the sequential protocol. We conclude that sequential PDT protocol promotes PDT efficacy by a process not involving iron translocation, but via promotion of the pro‐apoptotic signal that derives from mitochondrial photodamage. Testing for iron translocation using fluorescent probes: red = RhoNox‐1 (Ferrous iron); green = LysoTracker Green (A) or MitoTracker Green (B–D). Iron is initially localized in lysosomes (A), not mitochondria (B). Treatment with Bafilomycin results in substantial translocalization to mitochondria (C), whereas a low level of lysosomal photodamage does not (D). Either effect can markedly promote the efficacy of subsequent mitochondrial photodamage but via different mechanisms.
      PubDate: 2014-04-01T05:53:54.988887-05:
      DOI: 10.1111/php.12270
       
  • Topical Photodynamic Therapy Using Different Porphyrin Precursors Leads to
           Differences in Vascular Photosensitization and Vascular Damage in Normal
           Mouse Skin
    • Authors: Tom A. Middelburg; Hannah C. Vijlder, Henriette S. Bruijn, Angélique Ploeg‐van den Heuvel, H. A. Martino Neumann, Ellen R. M. Haas, Dominic J. Robinson
      Pages: 896 - 902
      Abstract: Different distributions of hexyl aminolevulinate (HAL), aminolevulinic acid (ALA) and methyl aminolevulinate (MAL) in the superficial vasculature are not well studied but they are hypothesized to play an important role in topical photodynamic therapy (PDT). The colocalization of fluorescent CD31 and protoporphyrin IX (PpIX) was calculated using confocal microscopy of mouse skin sections to investigate the vascular distribution after topical application. Vascular damage leads to disruption of the normal endothelial adherens junction complex, of which CD144 is an integral component. Therefore, normal CD31 combined with loss of normal fluorescent CD144 staining was visually scored to assess vascular damage. Both the vascular PpIX concentration and the vascular damage were highest for HAL, then ALA and then MAL. Vascular damage in MAL was not different from normal contralateral control skin. This pattern is consistent with literature data on vasoconstriction after PDT, and with the hypothesis that the vasculature plays a role in light fractionation that increases efficacy for HAL and ALA‐PDT but not for MAL. These findings indicate that endothelial cells of superficial blood vessels synthesize biologically relevant PpIX concentrations, leading to vascular damage. Such vascular effects are expected to influence the oxygenation of tissue after PDT which can be important for treatment efficacy. The ability of the vasculature to synthesize PpIX and be damaged by PDT was compared between HAL, ALA and MAL in mouse skin using confocal microscopy and fluorescent CD31 and CD144 antibodies. Colocalization of CD31 and PpIX (left images) was calculated to measure endothelial PpIX synthesis. Vascular damage was scored as loss of normal CD144 staining (right images). Both PpIX synthesis and vascular damage were highest for HAL, then ALA, then MAL. This illustrates that superficial blood vessels synthesize biologically relevant amounts of PpIX. Vascular responses can limit oxygen supply during or after PDT and are expected to influence outcome.
      PubDate: 2014-04-07T02:13:43.026001-05:
      DOI: 10.1111/php.12271
       
  • Autonomous Portable Solar Ultraviolet Spectroradiometer (APSUS) – a
           New CCD Spectrometer System for Localized, Real‐Time Solar
           Ultraviolet (280–400 nm) Radiation Measurement
    • Authors: Rebecca Hooke; Andy Pearson, John O'Hagan
      Pages: 903 - 910
      Abstract: Terrestrial solar ultraviolet (UV) radiation has significant implications for human health and increasing levels are a key concern regarding the impact of climate change. Monitoring solar UV radiation at the earth's surface is therefore of increasing importance. A new prototype portable CCD (charge‐coupled device) spectrometer‐based system has been developed that monitors UV radiation (280–400 nm) levels at the earth's surface. It has the ability to deliver this information to the public in real time. Since the instrument can operate autonomously, it is called the Autonomous Portable Solar Ultraviolet Spectroradiometer (APSUS). This instrument incorporates an Ocean Optics QE65000 spectrometer which is contained within a robust environmental housing. The APSUS system can gather reliable solar UV spectral data from approximately April to October inclusive (depending on ambient temperature) in the UK. In this study the new APSUS unit and APSUS system are presented. Example solar UV spectra and diurnal UV Index values as measured by the APSUS system in London and Weymouth in the UK in summer 2012 are shown. A new prototype portable CCD (charge‐coupled device) spectrometer‐based instrument called APSUS (Autonomous Portable Solar Ultraviolet Spectroradiometer) has been developed which monitors spectral UV (280–400 nm) radiation levels at the earth's surface. The APSUS system enables the UV index to be calculated and disseminated to the public in real time. The APSUS unit incorporates an Ocean Optics QE65000 spectrometer contained within a robust environmental housing. It can gather reliable data from approximately April to October inclusive (depending on ambient temperature) in the UK. In this study the new APSUS unit and APSUS system are presented.
      PubDate: 2014-03-10T06:02:14.357245-05:
      DOI: 10.1111/php.12251
       
  • Occupational UV Exposure of Environmental Agents in Valencia, Spain
    • Authors: María‐Antonia Serrano; Javier Cañada, Juan Carlos Moreno, Gonzalo Gurrea,
      Pages: 911 - 918
      Abstract: Excessive exposure to ultraviolet radiation (UVR) is considered the most important environmental risk factor in the development of melanoma and skin cancer. Outdoor workers are among those with the highest risk from exposure to solar UVR, as their daily activities constantly expose them to this radiation source. A study was carried out in Valencia, Spain, in summer 2012 and involved a group of 11 workers for a period of six 2‐day recordings. Sensitive spore‐film filter‐type personal dosimeters (VioSpor) were used to measure erythemal UVR received by environmental agents in the course of their daily work. Median 2‐day UV exposure was 6.2 standard erythema dose (SED), with 1 SED defined as effective 100 J m−2 when weighted with the Commission Internationale de L′Eclairage's (CIE) erythemal response function. These workers were found to receive a median of 8.3% total daily ambient ultraviolet erythemal radiation. Comparison with the occupational UV exposure limit showed that the subjects had received an erythemal UV dose in excess of occupational guidelines, indicating that protective measures against this risk are highly advisable. The aim of this paper is to measure UV exposure of environmental agents in their occupational schedules in summer in Valencia province (Spain) using VioSpor personal dosimeters attached to several parts of their bodies. Due to its geographical situation, Valencia receives large UVR doses throughout the year, and the work of environmental agents is directly related to the protection, care, and custody of natural, often in mountainous areas. Comparison with the occupational UV exposure limit showed that the agents received an erythemal UV dose in excess of occupational guidelines, indicating that protective measures against this risk are highly advisable.
      PubDate: 2014-02-26T06:53:27.477532-05:
      DOI: 10.1111/php.12252
       
  • Measuring Exposure to Solar Ultraviolet Radiation Using a Dosimetric
           Technique: Understanding Participant Compliance Issues
    • Authors: Jiandong Sun; Robyn M. Lucas, Simone L. Harrison, Ingrid Mei, David C. Whiteman, Rebecca Mason, Madeleine Nowak, Alison M. Brodie, Michael G. Kimlin
      Pages: 919 - 924
      Abstract: Personal ultraviolet dosimeters have been used in epidemiological studies to understand the risks and benefits of individuals' exposure to solar ultraviolet radiation (UVR). We investigated the types and determinants of noncompliance associated with a protocol for use of polysulphone UVR dosimeters. In the AusD Study, 1002 Australian adults (aged 18–75 years) were asked to wear a new dosimeter on their wrist each day for 10 consecutive days to quantify their daily exposure to solar UVR. Of the 10 020 dosimeters distributed, 296 (3%) were not returned or used (Type‐I noncompliance) and other usage errors were reported for 763 (8%) returned dosimeters (Type‐II noncompliance). Type‐I errors were more common in participants with predominantly outdoor occupations. Type‐II errors were reported more frequently on the first day of measurement; weekend days or rainy days; and among females; younger people; more educated participants or those with outdoor occupations. Half (50%) the participants reported a noncompliance error on at least 1 day during the 10‐day period. However, 92% of participants had at least 7 days of usable data without any apparent noncompliance issues. The factors identified should be considered when designing future UVR dosimetry studies. Among 10 020 polysulphone UV dosimeters distributed in the AusD Study, the majority (89%) were returned with no reported issues, but 3% were not returned or used and 8% were returned with self‐reported usage errors such as “missing some time,” “covered by clothing,” or “dosimeter got wet” that may potentially compromise the measurement quality. We found these noncompliance issues were more frequently reported on the first day of measurement; weekend days or rainy days; and among females; younger people; more educated participants or those with predominantly outdoor occupations. These factors should be considered when designing future UV dosimetry studies.
      PubDate: 2014-03-24T06:03:12.273723-05:
      DOI: 10.1111/php.12265
       
  • Quantification of Ocular Biologically Effective UV Exposure for Different
           Rotation Angle Ranges Based on Data from a Manikin
    • Authors: Liwen Hu; Fang Wang, Nan‐Ning Ou‐Yang, Na Gao, Qian Gao, Tiantian Ge, Yanyan Gao, Guangcong Liu, Yang Zheng, Yang Liu
      Pages: 925 - 934
      Abstract: Human outdoor activities are randomly orientated at different angles to the sun. To quantify the ocular UV and biologically effective UV (UVBE; i.e. the ocular UV irradiance exposure for photokeratitis (UVpker), photoconjunctivitis (UVpcon), and cataract (UVcat)) exposure for different rotation angle ranges, a rotating manikin was used to monitor the ocular UV exposure at different rotation angles in clear skies during July 2010 in Sanya, China. As a result, the ocular UV and UVBE irradiance was directly influenced by the rotation angle variations, primarily for the 120° rotation angle ranges facing the morning and afternoon sun when the solar elevation was lower than 60°; during these times, the UV and UVBE spectral irradiance decreased as the rotation angle increased. When compared to the 360° rotation angle ranges (which were considered to be the average exposure situation), the cumulative ocular UVBE for 60°, 120° and 180° rotation angle ranges were maximally 91% (UVcat), 94% (UVpker) and 121% (UVpcon); 71% (UVcat), 74% (UVpker) and 95% (UVpcon); 42%(UVcat), 45%(UVpker) and 55% (UVpcon) higher respectively. Meanwhile, the cumulative ocular UVBE for the 180° rotation angle ranges facing away from the sun were 46% (UVpker), 59% (UVpcon) and 45% (UVcat) lower. To improve the understanding of solar UV and the biologically effective UV exposure at eye (UVBE), this study monitored the ocular UV exposure at different rotation angles using a rotating manikin in clear skies during July 2010 in Sanya, China. The rotation angle ranges were the ranges of the eye facing the sun or facing away from the sun; for example, the 60° rotation angle range facing the sun was the rotation angle of 330° to 30°, and the 180° rotation angle range facing away from the sun included the rotation angles between 90° and 270°.
      PubDate: 2014-03-24T06:07:08.6413-05:00
      DOI: 10.1111/php.12267
       
  • Measurements of pilots’ occupational solar UV exposure
    • Authors: Adrian Chorley; Michael Higlett, Katarzyna Baczynska, Robert Hunter, Marina Khazova
      First page: 935
      Abstract: It is known that ultraviolet radiation (UVR) increases by 10-12% every 1,000 m altitude; UVR at the 10, 000 m of typical cruise altitude for commercial aircraft may be 2-3 times higher than at ground level. Information on the levels of solar UV exposures is essential for the assessment of the occupational risk of pilots developing sun-related eye disorders and skin cancers. The aim of the study was to investigate how UV hazard exposures can be measured during flights so that the occupational dose can be ascertained and compared with international guidance. This paper describes the development of instrumentation for automated time-stamped spectral measurements which were collected using bespoke automation software. The software enables the advanced acquisition techniques of automated dark signal capture and multiband integration control optimising the dynamic performance of the spectrometer over the full spectral range. The equipment was successfully tested in a number of aircraft and helicopter flights during 2012-13 and illustrated in this paper on an example of a Gatwick-Alicante flight. This article is protected by copyright. All rights reserved.
      PubDate: 2014-03-11T07:46:34.097815-05:
      DOI: 10.1111/php.12269
       
  • Two Methods for Retrieving UV Index for All Cloud Conditions from Sky
           Imager Products or Total SW Radiation Measurements
    • Authors: Jordi Badosa; Josep Calbó, Richard Mckenzie, Ben Liley, Josep‐Abel González, Bruce Forgan, Charles N. Long
      Pages: 941 - 951
      Abstract: Cloud effects on UV Index (UVI) and total solar radiation (TR) as a function of cloud cover and sunny conditions (from sky images) as well as of solar zenith angle (SZA) are assessed. These analyses are undertaken for a southern‐hemisphere mid‐latitude site where a 10‐years dataset is available. It is confirmed that clouds reduce TR more than UV, in particular for obscured Sun conditions, low cloud fraction (60°). Similarly, local short‐time enhancement effects are stronger for TR than for UV, mainly for visible Sun conditions, large cloud fraction and large SZA. Two methods to estimate UVI are developed: (1) from sky imaging cloud cover and sunny conditions, and (2) from TR measurements. Both methods may be used in practical applications, although Method 2 shows overall the best performance, as TR allows considering cloud optical properties. The mean absolute (relative) differences of Method 2 estimations with respect to measured values are 0.17 UVI units (6.7%, for 1 min data) and 0.79 Standard Erythemal Dose (SED) units (3.9%, for daily integrations). Method 1 shows less accurate results but it is still suitable to estimate UVI: mean absolute differences are 0.37 UVI units (15%) and 1.6 SED (8.0%). Cloud effects on UV Index (UVI) and total solar radiation (TR) are assessed. The role of cloud cover and sunny conditions (from sky images) and of solar zenith angle is investigated. The analyses are undertaken for a southern‐hemisphere mid‐latitude site where a 10‐years dataset is available. It is confirmed that clouds affect TR more than UVI, both in reducing and enhancing the cloud‐free radiation. From the analyses, two methods to estimate UVI are developed: (1) from sky imaging cloud cover and sunny conditions, and (2) from TR measurements. Methods' estimations are compared with measurements.
      PubDate: 2014-04-17T00:50:50.357746-05:
      DOI: 10.1111/php.12272
       
  • Preparation and Characterization of Uniform Near IR Polystyrene
           Nanoparticles
    • Authors: Michal Pellach; Shlomo Margel
      Pages: 952 - 956
      Abstract: Biomaterials for in vivo fluorescence imaging are required to be biocompatible, nontoxic, photostable and highly fluorescent. Fluorescence must be in the near infrared (NIR) region of the electromagnetic spectrum to avoid absorption and autofluorescence of endogenous tissues. NIR fluorescent polystyrene nanoparticles may be considered ideal biomaterials for in vivo imaging applications. These NIR nanoparticles were prepared by a swelling process of polystyrene template nanoparticles with a hydrophobic NIR dye dissolved in a water‐miscible swelling solvent, a method developed for preparation of nonbiodegradable nanoparticles, for NIR fluorescent bioimaging applications. This method overcomes common problems that occur with dye entrapment during nanoparticle formation such as loss of fluorescence and size polydispersity. Fluorescence intensity of the nanoparticles was found to be size dependent, and was optimized for differently sized nanoparticles. The resulting NIR nanoparticles were also found to be more fluorescent and highly photostable compared to the free dye in solution, showing their potential as biomaterials for in vivo fluorescence imaging. In vivo fluorescence imaging requires the use of near IR fluorescent imaging agents, to avoid the absorbance and autofluorescence of endogenous tissues that occur at visible wavelengths. Near IR dye was encapsulated into polystyrene nanoparticles via a swelling process. The dye encapsulation process was performed for a series of differently sized nanoparticles, without affecting the relatively uniform size distribution of each size. The method used was found to be appropriate for nanoparticles averaging approximately 20–100 nm in size. The resulting nanoparticles were highly fluorescent and highly photostable, and with appropriate surface modification, have potential for biological and in vivo imaging applications.
      PubDate: 2014-02-20T04:11:43.381632-05:
      DOI: 10.1111/php.12244
       
 
 
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