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  Subjects -> CHEMISTRY (Total: 765 journals)
    - ANALYTICAL CHEMISTRY (45 journals)
    - CHEMISTRY (530 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (25 journals)
    - INORGANIC CHEMISTRY (40 journals)
    - ORGANIC CHEMISTRY (40 journals)
    - PHYSICAL CHEMISTRY (63 journals)

CHEMISTRY (530 journals)            First | 1 2 3 4 5 6 | Last

Journal of Heterocyclic Chemistry     Hybrid Journal   (Followers: 5)
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: 3)
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: 22)
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: 141)
Journal of Membrane Science     Hybrid Journal   (Followers: 9)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 1)
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  
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 6)
Journal of Molecular Structure     Hybrid Journal   (Followers: 3)
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: 148)
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: 12)
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: 226)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 15)
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: 4)
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: 15)
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: 1)
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 Reviews     Open Access   (Followers: 15)
Nanomaterials and the Environment     Open Access  

  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  [1602 journals]   [SJR: 0.709]   [H-I: 86]
  • Therapeutic Effect of Irradiation of Magnetic Infrared Laser on
           Osteoarthritis Rat Model
    • Authors: Chul‐Hwan Moon; Ogon Kwon, Chang‐Hoon Woo, Young‐Sam Kwon, Soo‐Jin Park, Chang‐Hyun Song, Sae‐Kwang Ku
      Pages: n/a - n/a
      Abstract: Osteoarthritis (OA) is a degenerative joint disease caused by articular cartilage loss. Many complementary and alternative medicines for OA have been reported so far, but the effectiveness is controversial. Previously, we have shown anti‐inflammatory effects of low level laser therapy with static magnetic field, magnetic infrared laser (MIL), in various animal models. Therefore, the beneficial effects were examined in OA rat model. Rats were divided by 6 groups; no treatment controls of sham and OA model, 3 MIL treatment groups of OA model at 6.65, 2.66 and 1.33 J/cm2, and Diclofenac group of OA model with 2 mg/kg diclofenac sodium. The OA control exhibited typical symptoms of OA, but 4‐week MIL treatment improved the functional movement of knee joint with reduced edematous changes. In addition, cartilage GAGs were detected more in all MIL treatment groups than OA control. It suggests 4‐week MIL irradiation has dose‐dependent anti‐inflammatory and chondroprotective effects on OA. Histopathological analyses revealed that MIL treatment inhibit the cartilage degradation and enhance chondrocyte proliferation. The fact that MIL has an additional potential for the cartilage formation and no adverse effects can be regarded as great advantages for OA treatment. These suggest that MIL can be useful for OA treatment. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-24T20:13:22.347013-05:
      DOI: 10.1111/php.12304
       
  • 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
       
  • Short‐term UV‐B Dose Stimulates Production of Protective
           Metabolites in Matricaria chamomilla Leaves
    • Authors: Veronika Petruľová; Zuzana Dučaiová, Miroslav Repčák
      Abstract: Physiological response of two cultivars of Matricaria chamomilla plants on UV irradiation was studied. The impact of used short‐time UV dose was evaluated in three time points; 2, 24 and 48 hours after irradiation. Used UV irradiation immediately resulted in changes in plant oxidative status monitored as increased concentration of H2O2. Decrease in chlorophyll a and b indicated the impact on photosynthetic apparatus. For phenolic secondary metabolites, an increase of total soluble phenols and AlCl3‐reactive flavonols was observed. The activity of main phenolic enzyme, phenylalanine ammonia‐lyase, increased with time after irradiation. Significant changes, mainly decreasing trends, in the content of free coumarins and their glycosidic precursors were observed. Enhanced accumulation in chlorogenic and 1,5‐dicaffeoylquinic acid and in (Z)‐isoform of dicycloethers was detected. From these results, the redirecting precursors of coumarin biosynthesis to biosynthesis of substances with higher antioxidative potential can be assumed. Different reactions in diploid and tetraploid plants were recorded, too. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-10T00:34:34.567533-05:
      DOI: 10.1111/php.12300
       
  • 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
       
  • Photophysical Properties and Singlet Oxygen Generation Efficiencies of
           Water‐Soluble Fullerene Nanoparticles
    • Authors: Alexander S. Stasheuski; Victor A. Galievsky, Alexander P. Stupak, Boris M. Dzhagarov, Mi Jin Choi, Bong Hyun Chung, Jin Young Jeong
      Abstract: Since various fullerene derivatives have been developed, it is necessary to explore their photophysical properties for potential use in photoelectronics and medicine. Here, we address the photophysical properties of newly synthesized water‐soluble fullerene‐based nanoparticles and polyhydroxylated fullerene as a representative water‐soluble fullerene derivative. They show broad emission band arising from a wide‐range of excitation energies. It is attributed to the optical transitions from disorder‐induced states, which decay in the nanosecond time range. We determine the kinetic properties of the singlet oxygen (1O2) luminescence generated by the fullerene nanoparticles and polyhydroxylated fullerene to consider the potential as photodynamic agents. Triplet state decay of the nanoparticles was longer than 1O2 lifetime in water. Singlet oxygen quantum yield of a series of the fullerene nanoparticles is comparably higher ranging from 0.15 to 0.2 than that of polyhydroxylated fullerene, which is about 0.06. This article is protected by copyright. All rights reserved.
      PubDate: 2014-06-04T01:30:20.060057-05:
      DOI: 10.1111/php.12294
       
  • The Photolytic Activity of Poly‐Arginine Cell Penetrating Peptides
           Conjugated to Carboxy‐tetramethylrhodamine is Modulated by Arginine
           Residue Content and Fluorophore Conjugation Site
    • Authors: Nandhini Muthukrishnan; Stephen Donovan, Jean-Philippe Pellois
      Abstract: Upon light irradiation, Fluorophore–cell‐penetrating peptide (Fl‐CPP) conjugates can disrupt the integrity of biological membranes. This activity can in turn be used to photoinduce the disruption of endocytic organelles and promote the delivery of entrapped macromolecules such as proteins or RNAs into live cells. Recent mechanistic studies have shown that ROS production by the fluorophore and a latent lytic ability of CPPs act in synergy to elicit photolysis. However, how the structure of fluorophore‐CPP conjugates impacts this synergistic activity remains unclear. Herein, using red blood cells (RBCs) as a model of biological membranes, we show that the number of arginine residues in a CPP as well as the position of fluorophore with respect to the CPP dramatically affect the photolytic activity of a fluorophore‐CPP conjugate. These factors should therefore be considered for the development of effective photoinducible delivery agents. Fluorophore–cell‐penetrating peptide (Fl‐CPP) conjugates can disrupt membranes of endocytic organelles upon light irradiation and promote the delivery of entrapped macromolecules such as proteins or nucleic acids into a cells’ cytosol. ROS production by the fluorophore and a latent lytic ability of CPPs act in synergy to elicit photolysis. In this report, using red blood cells as a model of biological membranes, we show that the number of arginine residues in a CPP as well as the position of fluorophore with respect to the CPP dramatically affect the photolytic activity of a fluorophore–CPP conjugate. These factors should therefore be considered for the development of effective photoinducible delivery agents.
      PubDate: 2014-06-03T02:28:50.442713-05:
      DOI: 10.1111/php.12288
       
  • Combination of Oral Vitamin D3 with Photodynamic Therapy Enhances Tumor
           Cell Death in a Murine Model of Cutaneous Squamous Cell Carcinoma
    • Authors: Sanjay Anand; Kishore R. Rollakanti, Ronald L. Horst, Tayyaba Hasan, Edward V. Maytin
      Abstract: Photodynamic therapy (PDT), in which 5‐ALA (a precursor for protoporphyrin IX, PpIX) is administered prior to exposure to light, is a nonscarring treatment for skin cancers. However, for deep tumors, ALA‐PDT is not always effective due to inadequate production of PpIX. We previously developed and reported a combination approach in which the active form of vitamin D3 (calcitriol) is given systemically prior to PDT to improve PpIX accumulation and to enhance PDT‐induced tumor cell death; calcitriol, however, poses a risk of hypercalcemia. Here, we tested a possible strategy to circumvent the problem of hypercalcemia by substituting natural dietary vitamin D3 (cholecalciferol; D3) for calcitriol. Oral D3 supplementation (10 days of a 10‐fold elevated D3 diet) enhanced PpIX levels 3‐ to 4‐fold, and PDT‐mediated cell death 20‐fold, in subcutaneous A431 tumors. PpIX levels and cell viability in normal tissues were not affected. Hydroxylated metabolic forms of D3 were only modestly elevated in serum, indicating minimal hypercalcemic risk. These results show that brief oral administration of cholecalciferol can serve as a safe neoadjuvant to ALA‐PDT. We suggest a clinical study, using oral vitamin D3 prior to PDT, should be considered to evaluate this promising new approach to treating human skin cancer. We report the results of a preclinical study in mice, showing that a combination of oral vitamin D (vit D3) and PDT can improve therapeutic killing of subcutaneous SCC tumors without the risk of hypercalcemia usually associated with calcitriol, the active hormonal form of vit D3. Dietary supplementation with vit D3 (10 days) enhanced PpIX levels, promoted tumor differentiation and proliferation and resulted in enhanced tumor cell death following PDT. These data suggest that a clinical study using oral vit D3 prior to PDT could establish a promising new approach for effective therapy of nonmelanoma skin cancer.
      PubDate: 2014-05-25T23:46:50.697173-05:
      DOI: 10.1111/php.12286
       
  • Risk of Ocular Exposure to Biologically Effective UV Radiation in
           Different Geographical Directions
    • Authors: Fang Wang; Liwen Hu, Qian Gao, Yanyan Gao, Guangcong Liu, Yang Zheng, Yang Liu
      Abstract: To quantify ocular exposure to solar ultraviolet radiation (UVR) and to assess the risk of eye damage in different geographical directions due to UVR exposure, we used a spectrometer and a manikin to measure horizontal ambient and ocular exposure UVR in different geographical directions at four different locations at the Northern Hemisphere. Describing the relationship of exposure to risk of eye damage requires the availability of UV hazard weighting function. So, we used the UV hazard weighting function (ICNIRP) proposed by International Commission on Non‐Ionizing Radiation Protection to determine the biologically effective UV irradiance (UVBEeye) and then cumulative effective radiant exposure (Heye) to shown the risk of eye. We found that in different geographical directions, distributions of ocular exposure to UVR were markedly different from those of horizontal ambient UVR. When the midday maximum SEA > 50°, eye received more UVR from the east and west directions during the morning and evening hours, respectively. However, when the midday maximum SEA 
      PubDate: 2014-05-23T02:26:28.883417-05:
      DOI: 10.1111/php.12287
       
  • Photo-oxidation of Tetrahydrobiopterin under UV Irradiation: Possible
           Pathways and Mechanisms
    • Authors: Andrey A. Buglak; Taisiya A. Telegina, Tamara A. Lyudnikova, Yulia L. Vechtomova, Mikhail S. Kritsky
      Abstract: Tetrahydrobiopterin (H4Bip) is a cofactor for several key enzymes, including NO-synthases and aromatic amino acid hydroxylases (AAHs). Normal functioning of the H4Bip regeneration cycle is extremely important for the work of AAHs. Oxidized pterins may accumulate if the H4Bip regeneration cycle is disrupted or if H4Bip autoxidation occurs. These oxidized pterins can photosensitize the production of singlet molecular oxygen 1O2 and thus cause oxidative stress. In this context, we studied the photo-oxidation of H4Bip in phosphate buffer at pH 7.2. We found that UV irradiation of H4Bip affected its oxidation rate (quantum yield Φ300 = (2.7 ± 0.4) × 10-3). The effect of UV irradiation at λ = 350 nm on H4Bip oxidation was stronger, especially in the presence of biopterin (Bip) (Φ350 = (9.7 ± 1.5) × 10-3). We showed that the rate of H4Bip oxidation linearly depends on Bip concentration. Experiments with KI, a selective quencher of triplet pterins at micromolar concentrations, demonstrated that the oxidation is sensitized by the triplet state biopterin 3Bip. Apparently, electron transfer sensitization (type I mechanism) is dominant. Energy transfer (type II mechanism) and singlet oxygen generation plays only a secondary role. The mechanisms of H4Bip photo-oxidation and their biological meaning are discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2014-05-20T01:28:08.047429-05:
      DOI: 10.1111/php.12285
       
  • Therapeutic Effects of Full Spectrum Light on the Development of Atopic
           Dermatitis-like Lesions in NC/Nga Mice
    • Authors: Tae-Rin Kwon; Seog Kyun Mun, Chang Taek Oh, Hyuckki Hong, Yeon Shik Choi, Bong-Jun Kim, Beom Joon Kim
      Abstract: Full spectrum light (FSL) includes UVA, visible light, and infrared light. Many studies have investigated the application of FSL in severe cases of atopic dermatitis (AD) in humans; however, FSL has not yet been studied in an animal model. The purpose of this study is to evaluate the therapeutic effects of FSL on AD-like skin lesions using NC/Nga mice, with the aim of mitigating itching and attenuating the expression of adhesion molecules. We examined the effects of FSL on mite allergen-treated NC/Nga mice by assessing skin symptom severity, ear thickness, serum IgE levels, and the cytokine expression. We examined the histology of lesions using hematoxylin–eosin, toluidine blue, and immunohistochemical staining. Our findings suggest that FSL phototherapy exerts positive therapeutic effects on Dermatophagoides farinae (Df)-induced AD-like skin lesions in NC/Nga mice by reducing IgE levels, thus promoting recovery of the skin barrier. The mechanisms by which FSL phototherapy exerts its effects may also involve the inhibition of scratching behavior, reduction of IL-6 levels, and reductions in adhesion molecule expression. The present study indicates that FSL phototherapy inhibits the development of AD in NC/Nga mice by suppressing cytokine, chemokine, and adhesion molecule expression, and thus, could potentially be useful in treating AD. This article is protected by copyright. All rights reserved.
      PubDate: 2014-05-19T04:05:44.278613-05:
      DOI: 10.1111/php.12284
       
  • Reversible Effects of Photodamage Directed Toward Mitochondria
    • Authors: David Kessel
      Abstract: When the initial effect of photodynamic therapy (PDT) involves mitochondrial photodamage, an early effect is loss of the mitochondrial membrane potential (ΔΨm). Using murine hepatoma 1c1c7 cells and a photosensitizing agent known to target mitochondria, we examined loss of ΔΨm, initiation of apoptosis and loss of viability as a function of time and light dose. There was a correlation between loss of viability and the rapid disappearance of ΔΨm, as detected by the potential-sensitive probe Mitotracker Orange (MTO). Loss of ΔΨm was, however, reversible even with a substantial loss of viability. Unless there was a supra-lethal level of photodamage, 1c1c7 cells recovered their mitochondrial membrane potential, even if the cell population was on the pathway to apoptosis and cell death. These results indicate that when mitochondria are the initial PDT target, a qualitative estimate of photokilling can be provided by assessing the initial loss of ΔΨm. This article is protected by copyright. All rights reserved.
      PubDate: 2014-05-14T01:41:55.27826-05:0
      DOI: 10.1111/php.12283
       
  • Activation of sperm EGFR by light irradiation is mediated by reactive
           oxygen species
    • Authors: Shiran Shahar; Pnina Hillman, Rachel Lubart, Debby Ickowicz, Haim Breitbart
      Abstract: To acquire fertilization competence, spermatozoa must undergo several biochemical and motility changes in the female reproductive tract, collectively called capacitation. Actin polymerization and the development of hyper-activated motility (HAM) are part of the capacitation process. In a recent study, we showed that irradiation of human sperm with visible light stimulates HAM through a mechanism involving reactive-oxygen-species (ROS), Ca2+ influx, protein-kinases A (PKA), and sarcoma-protein-kinase (Src). Here we showed that this effect of light on HAM is mediated by ROS-dependent activation of the epidermal-growth-factor-receptor (EGFR). Interestingly, ROS mediated HAM even when the EGFR was activated by EGF, the physiological ligand of EGFR. Light irradiation stimulated ROS-dependent actin polymerization, and this effect was abrogated by PBP10, a peptide which activates the actin-severing protein, gelsolin, and causes actin-depolymerization in human sperm. Light stimulated tyrosine phosphorylation of Src-dependent gelsolin, resulting in enhanced HAM. Thus, light irradiation stimulates HAM through a mechanism involving Src-mediated actin polymerization. Light stimulated HAM and in-vitro-fertilization (IVF) rate in mouse sperm, and these effects were mediated by ROS and EGFR. In conclusion, we show here that irradiation of sperm with visible light, enhances their fertilization capacity via a mechanism requiring ROS, EGFR and HAM. This article is protected by copyright. All rights reserved.
      PubDate: 2014-05-02T04:12:21.43452-05:0
      DOI: 10.1111/php.12281
       
  • Photoactive Titania Float for Disinfection of Water; Evaluation of Cell
           Damage by Bioanalytical Techniques
    • Authors: R. Shwetharani; M. S. Jyothi, P. D. Laveena, R. Geetha Balakrishna
      Abstract: A photoactive float was fabricated with the modified titania to cause a feasible disinfection of water, contaminated with E. coli. The commercially available titania was doped with neodymium by pulverization technique to enhance its activity in sunlight and a multiapproach technique was used to evaluate the extended efficiency of the doped sample. X-ray diffraction patterns depicted the retention of anatase phase on doping and the existence of neodymium was confirmed by the energy dispersive atomic X-ray analysis and the X-ray photoelectron spectroscopy. Transmission electron microscopy and Bruner–Emmett–Teller analysis depicted a marginal increase in the particle size and a decrease in the surface area, respectively. Doping induces semiconductor behavior with lower band energy that could respond to visible light and exhibit better disinfection activity. The “f” and “d” transitions of the lanthanide in doped sample caused new electronic behavior of trapping/detrapping effect together with bandgap narrowing. The amount of malondialdehyde, protein, DNA and RNA released on destruction of E. coli was observed to be 0.915 × 10−3 μg mL−1, 859.912 μg mL−1, 20.173 μg mL−1 and 1146.073 μg mL−1, respectively. The above analytical methods along with standard plate count method substantiated the enhanced disinfection efficiency of the doped sample in sunlight. The titania-coated polymeric float effectively disintegrates the bacteria by adsorption and diffusion to cause complete disintegration of cell membrane and thus disinfects water.
      PubDate: 2014-04-25T02:24:21.840183-05:
      DOI: 10.1111/php.12277
       
  • Preliminary Ultrasonication Affects the Rate of the Bacteriorhodopsin
           Bleaching and the Effectiveness of the Reconstitution Process in
           Bacterioopsin
    • Authors: Anna B. Druzhko; Sergey K. Pirutin
      Abstract: The formation process of polymer films based on bacteriorhodopsin (BR) analogs requests a high amount of BR samples one time only. The common technique for apomembrane formation (preparation of bacterioopsin, BO) is not designed to be operated with high concentrations and high volumes of BR, so the use of this technique results in a low rate of BR bleaching. To accelerate the process of BR bleaching preliminary sonication was used. It was used just as preliminary sonication before bleaching of BR samples, so also sonication was used before reconstitution of resulted BO samples. These modifications of the common technique lead to an acceleration of BR bleaching and an increase in effectiveness of reconstitution of BO in comparison with the nonmodified technique. The quantitative results of sonication's effect on the bleaching acceleration and the effectiveness of reconstitution are different depending on the BR strains. A high-concentrated BR suspension is bleached in a PHA reaction at a very low rate. To accelerate this reaction the preliminary ultrasonication (kGz range) has been used. This is largely responsible for increasing the rate of this reaction and high quality of resulted apomembrane. A further process of apomembrane reconstitution with retinal relies upon preliminary ultrasonication (kGz range) of a high-concentrated apomembrane either. After ultrasonication the effectiveness of reconstitution has been increased. The quantitative characteristics of two processes depend upon types of BR strains. So, we offer a simple way to enhance the PM bleaching and AM reconstitution.
      PubDate: 2014-04-21T00:56:14.708601-05:
      DOI: 10.1111/php.12275
       
  • Sun exposure and Protection Behavior of Danish Farm Children: Parental
           Influence on Their Children
    • Authors: Mette Bodekær Larsen; Bibi Petersen, Peter Alshede Philipsen, Antony Young, Elisabeth Thieden, Hans Christian Wulf
      Abstract: Healthy sun habits acquired in childhood could reduce skin cancer incidence. We examined the sun exposure and protection behavior of an expected high-exposure group of children, and the association to their parents. Open, prospective cohort study. One hundred and thirty nine participants (40 families) kept daily sun behavior diaries (sun exposure, sunscreen use, sunburns) over a 4-month summer period (15 985 diary days). The Pigment Protection Factor (PPF), an objective measure of sun exposure, was measured at two body sites, before and after summer. All participants presented data from the same 115 days. Risk behavior (sun exposure of upper body) took place on 9.5 days (boys) and 15.6 days (girls). Sunburn and sunscreen use were infrequent. Boys’ sun exposure resulted in an increased photo protection over the study period of 1.7 SED (upper arm) and 0.8 SED (shoulder) to elicit erythema. Corresponding values for girls were as follows: 0.9 SED (upper arm) and 0.5 SED (shoulder). Boys’ sunscreen use correlated to their mothers’ (r = 0.523, P = 0.02). Girls’ number of risk days (r = 0.552, P = 0.005) and sun exposure (upper arm: r = 0.621, P 
      PubDate: 2014-04-21T00:56:11.670107-05:
      DOI: 10.1111/php.12280
       
  • “Pointsource” Delivery of a Photosensitizer Drug and Singlet
           Oxygen: Eradication of Glioma Cells In Vitro
    • Authors: Ashwini A. Ghogare; Imran Rizvi, Tayyaba Hasan, Alexander Greer
      Abstract: We describe a pointsource sensitizer-tipped microoptic device for the eradication of glioma U87 cells. The device has a mesoporous fluorinated silica tip which emits singlet oxygen molecules and small quantities of pheophorbide sensitizer for additional production of singlet oxygen in the immediate vicinity. The results show that the device surges in sensitizer release and photokilling with higher rates about midway through the reaction. This was attributed to a self-amplified autocatalytic reaction where released sensitizer in the extracellular matrix provides positive feedback to assist in the release of additional sensitizer. The photokilling of the glioma cells was analyzed by global toxicity and live/dead assays, where a killing radius around the tip with ~0.3 mm precision was achieved. The implication of these results for a new PDT tool of hard-to-resect tumors, e.g. in the brain, is discussed. A sensitizer-tipped microoptic device for the eradication of glioma U87 cells is described. The device has a porous silica tip that emits 1O2 molecules and small quantities of pheophorbide sensitizer for additional production of 1O2 in the immediate vicinity. The implication of these results for a new PDT tool of hard-to-resect tumors, e.g. in the brain, is discussed.
      PubDate: 2014-04-21T00:54:44.205021-05:
      DOI: 10.1111/php.12274
       
  • Excited State Photoreaction between the Indole Side Chain of Tryptophan
           and Halocompounds Generates New Fluorophores and Unique Modifications
    • Authors: Carol L. Ladner; Khai Tran, Mary Le, Raymond J. Turner, Robert A. Edwards
      Abstract: Photoreaction of indole containing compounds with chloroform and other trichlorocompounds generates products with redshifted fluorescence. In proteins, this reaction can be used for the fluorescent detection of proteins. Little characterization of products generated through the photochemical reaction of indoles with halocompounds has been done, yet is fundamental for the development of other fluorophores, protein labeling agents, and bioactive indole derivatives. Here, we have characterized which isomers form in the photoreaction between tryptophan and chloroform using 1H-NMR of tryptophan and methylated derivatives to reveal that the two major products that are formed result from modification at the 4- and 6-carbon positions of the indole ring. Reaction at position 6 generates 6-formyl tryptophan and the reaction at position 4 generates an imine because the formyl derivative that is initially formed reacts further with the tryptophan amine group. The spectroscopic properties and product molecular weights of photoproducts formed from photoreaction of tryptophan with other trihalo and monohalocompounds are also determined. The indole ring of tryptophan can be modified with various additions from halocompounds, including the addition of labels to the indole ring via methylene groups. This opens possibilities for generating novel tryptophan based fluorophores and protein labeling strategies using this photochemistry. Several fluorophores were produced by photoreactions between the amino acid tryptophan and halocompounds. The reaction with trihalocompounds in aqueous solution yielded products with carbonyl groups conjugated to the aromatic system at the 4 and 6 positions of the indole fluorophore and led to emission near 500 nm. This photoreaction also proceeded with monohalocompounds, but resulted in additions to the indole fluorophore without enlarging the conjugated systems so that the fluorescence properties of the indole in tryptophan did not change significantly.
      PubDate: 2014-04-17T05:54:23.005685-05:
      DOI: 10.1111/php.12279
       
  • Observation of Magnetic Field Effects on Transient Fluorescence Spectra of
           Cryptochrome 1 From Homing Pigeons
    • Authors: Xian-li Du; Jing Wang, Wei-song Pan, Qi-jun Liu, Xiao-jie Wang, Wen-jian Wu
      Abstract: Cryptochromes are suggested to be involved in the bird magnetoreception based on the radical pair mechanism (RPM), a well established theory of weak magnetic field effects on chemical reactions. Two members of cryptochrome/photolyase family were found to respond to magnetic field, however, no direct responses of bird cryptochrome to magnetic field as weak as the Earth's magnetic field have been obtained so far. In this study, we used transient fluorescence spectroscopy to characterize the weak magnetic field effects of bird cryptochromes. To do this, we cloned the cryptochrome 1 gene (clCRY1) from the retina of homing pigeons (Columba livia), expressed it in insect Sf9 cells and analyzed the transient fluorescence of purified clCRY1 by application of 45–300 μT magnetic fields. The flavin adenine dinucleotide (FADox) and glucose oxidase (GOD) in PBS buffer were set as controls which could be excited by light to generate radicals, but would not be sensitive to magnetic field. We observed that the transient fluorescence spectra of clCRY1 were sensitive to the applied magnetic field at room temperature. Our result provides a new proof of the cryptochrome-based model of avian magnetoreception in vitro. Cryptochrome is suggested to be the most probable candidate magnetoreceptor in bird magnetoreception. Two members of cryptochrome/photolyase family have been found to be sensitive to the magnetic field and the magnetic sensitivity was proposed to be the general feature of this protein family. In this study, we constructed a magnetic field by Helmholtz coils and tested the magnetic field effects on the transient fluorescence of cryptochrome from homing pigeons at room temperature. Our results showed that, comparing to other flavin controls, the transient fluorescence of clCRY1 protein is sensitive to microtesla level magnetic field.
      PubDate: 2014-04-17T05:54:05.966108-05:
      DOI: 10.1111/php.12276
       
  • Measurements of pilots’ occupational solar UV exposure
    • Authors: Adrian Chorley; Michael Higlett, Katarzyna Baczynska, Robert Hunter, Marina Khazova
      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
       
  • Shade Provision for UV Minimization: A Review
    • Authors: Alfio V. Parisi; David J. Turnbull
      First page: 479
      Abstract: Minimizing exposure to ultraviolet (UV) radiation is an essential component of skin cancer prevention. Providing and using natural and built shade is an effective protection measure against harmful UV. This article describes the factors that must be addressed to ensure quality, effective, well‐designed shade and recommends best practice approaches to improving the protection factor (PF) of shade structures. It identifies examples of interventions to increase shade availability and use, and examples of effective shade based on measured protection factors or measured reductions in UV exposures. Finally, this article considers examples of best practice for undertaking shade audits. The article is based on refereed articles and reviews, reports, conference papers and shade practice and policies from reports and on web sites. Articles for the Australian setting are considered first, followed by those in an international setting. Providing and using natural and built shade is an effective protection measure against harmful UV. This article describes the factors that must be addressed to ensure quality, effective, well‐designed shade and recommends best practice approaches to improving the protection factor of shade structures. It identifies examples of interventions to increase shade availability and use, and examples of effective shade based on measured protection factors or measured reductions in UV exposures. Finally, this article considers examples of best practice for undertaking shade audits.
      PubDate: 2014-02-04T07:19:14.843109-05:
      DOI: 10.1111/php.12237
       
  • The Effect of Loading Palladium on Zinc Oxide on the Photocatalytic
           Degradation of Methyl tert‐Butyl Ether (MTBE) in Water
    • Authors: Zaki S. Seddigi; Saleh A. Ahmed, Shahid P. Ansari, Naeema H. Yarkandi, Ekram Danish, Abdullah Abu Alkibash, Mohammed D. Y. Oteef, Shakeel Ahmed
      First page: 491
      Abstract: A series of heterogeneous catalysts was prepared by doping zinc oxide with different palladium loadings in the range of 0.5%–1.5%. The prepared catalysts were characterized by SEM, TEM and XRD. These catalysts were applied to study the degradation of Methyl tert‐Butyl Ether (MTBE). An amount of 100 mg of each of these catalysts was added to an aqueous solution of 100 ppm of MTBE. The resulting mixtures were irradiated with UV light for a period of 5 h. A 99.7% removal of MTBE was achieved in the case of the zinc oxide photocatalyst particles doped with 1% Pd. The photoreaction was found to be a first‐order one. Approximately complete removal of MTBE was achieved within 5 h by using ZnO particles doped with 1% Pd. The efficient degradation of MTBE is due to the higher concentration of the hydroxyl radicals and to the presence of Pd that controls the recombination of photogenerated electron hole pair.
      PubDate: 2014-02-23T03:27:44.802009-05:
      DOI: 10.1111/php.12242
       
  • Characterization of the Triplet State of Tanshinone IIA and its Reactivity
           by Laser Flash Photolysis
    • Authors: Kun Li; Qin Zhang, Mei Wang, Rongrong Zhu, Xiaoyu Sun, Xianzheng Wu, Shi-Long Wang
      First page: 496
      Abstract: Tanshinone IIA (Tan IIA) has the properties of cardiovascular protection, anti‐inflammation, antioxidation and anticancer. Its light‐induced instability has drawn our interests in its photochemistry. Therefore, laser flash photolysis herein was used to investigate the transient photochemistry of Tan IIA. Our results show that direct photoexcitation by 355 nm laser pulses or photosensitization by energy transfer can lead to the formation of the triplet state of Tan IIA (3Tan IIA*). The triplet absorption spectrum and molar absorption coefficient, and ISC quantum yield were determined. Self‐quenching of 3Tan IIA* by its ground state was identified as an autooxidation reaction. 3Tan IIA* was proved to react quickly with N, N‐dimethylaniline, tert‐butylhydroquinone and propyl gallate via electron transfer with the diffusion‐controlled rate constants. One of the products with maximum absorption around 390 nm was assigned to the radical anion of Tan IIA. Our results indicate that 3Tan IIA* is a reactive transient species and can be generated by photosensitization or direct photoexcitation. According to our results, the possible role of Tan IIA as a photosensitizer to induce potential phototoxicity via Type‐II pathway in the presence of O2 can be predicted. Photosensitization by energy transfer from triplet state of photosensitizer to Tan IIA or direct photoexcitation of Tan IIA by 355 nm laser pulses lead to generation of triplet state of Tan IIA which can react with DMA and TBHQ and PGA via electron transfer in acetonitrile and experience self‐quenching reaction via autooxidation in cyclohexane.
      PubDate: 2014-01-27T02:25:02.773682-05:
      DOI: 10.1111/php.12220
       
  • Photophysical Properties of Metal Ion Functionalized NaY Zeolite
    • Authors: Tian-Wei Duan; Bing Yan
      First page: 503
      Abstract: A series of luminescent ion exchanged zeolite are synthesized by introducing various ions into NaY zeolite. Monometal ion (Eu3+, Tb3+, Ce3+, Y3+, Zn2+, Cd2+, Cu2+) exchanged zeolite, rare‐earth ion (Eu3+, Tb3+, Ce3+) exchanged zeolite modified with Y3+ and rare‐earth ion (Eu3+, Tb3+, Ce3+) exchanged zeolite modified with Zn2+ are discussed here. The resulting materials are characterized by Fourier transform infrared spectrum radiometer (FTIR), XRD, scanning electronic microscope (SEM), PLE, PL and luminescence lifetime measurements. The photoluminescence spectrum of NaY indicates that emission band of host matrix exhibits a blueshift of about 70 nm after monometal ion exchange process. The results show that transition metal ion exchanged zeolites possess a similar emission band due to dominant host luminescence. A variety of luminescence phenomenon of rare‐earth ion broadens the application of zeolite as a luminescent host. The Eu3+ ion exchanged zeolite shows white light luminescence with a great application value and Ce3+ exchanged zeolite steadily exhibits its characteristic luminescence in ultraviolet region no matter in monometal ion exchanged zeolite or bimetal ions exchanged zeolite. A series of luminescent ion exchanged zeolite are synthesized by introducing various ions into NaY zeolite. The produced materials can be divided into three types: metal exchanged zeolite, rare‐earth exchanged NaY zeolite modified with Y3+ and rare‐earth exchanged NaY zeolite modified with Zn2+.
      PubDate: 2014-01-28T00:27:09.939036-05:
      DOI: 10.1111/php.12235
       
  • Triplet–Triplet Energy Transfer from a UV‐A Absorber
           Butylmethoxydibenzoylmethane to UV‐B Absorbers
    • Authors: Azusa Kikuchi; Nozomi Oguchi-Fujiyama, Kazuyuki Miyazawa, Mikio Yagi
      First page: 511
      Abstract: The phosphorescence decay of a UV‐A absorber, 4‐tert‐butyl‐4′‐methoxydibenzolymethane (BMDBM) has been observed following a 355 nm laser excitation in the absence and presence of UV‐B absorbers, 2‐ethylhexyl 4‐methoxycinnamate (octyl methoxycinnamate, OMC) and octocrylene (OCR) in ethanol at 77 K. The lifetime of the lowest excited triplet (T1) state of BMDBM is significantly reduced in the presence of OMC and OCR. The observed quenching of BMDBM triplet by OMC and OCR suggests that the intermolecular triplet–triplet energy transfer occurs from BMDBM to OMC and OCR. The T1 state of OCR is nonphosphorescent or very weakly phosphorescent. However, we have shown that the energy level of the T1 state of OCR is lower than that of the enol form of BMDBM. Our methodology of energy‐donor phosphorescence decay measurements can be applied to the study of the triplet–triplet energy transfer between UV absorbers even if the energy acceptor is nonphosphorescent. In addition, the delayed fluorescence of BMDBM due to triplet–triplet annihilation was observed in the BMDBM–OMC and BMDBM–OCR mixtures in ethanol at 77 K. Delayed fluorescence is one of the deactivation processes of the excited states of BMDBM under our experimental conditions. The intermolecular triplet–triplet energy transfer from 4‐tert‐butyl‐4′‐methoxydibenzolymethane (BMDBM) to octocrylene (OCR) has been observed by measuring the phosphorescence decay of BMDBM following a 355 nm laser excitation. The lifetime of the lowest excited triplet state of BMDBM is significantly reduced in the presence of OCR. Our methodology of energy‐donor phosphorescence decay measurements can be applied to the study of the triplet–triplet energy transfer between UV absorbers even if the energy acceptor is nonphosphorescent.
      PubDate: 2014-01-06T04:06:34.755192-05:
      DOI: 10.1111/php.12222
       
  • Photoacclimation Responses of the Brown Macroalga Sargassum Cymosum to the
           Combined Influence of UV Radiation and Salinity: Cytochemical and
           Ultrastructural Organization and Photosynthetic Performance
    • Authors: Luz K. Polo; Marthiellen R. L. Felix, Marianne Kreusch, Debora T. Pereira, Giulia B. Costa, Carmen Simioni, Luciane C. Ouriques, Fungyi Chow, Fernanda Ramlov, Marcelo Maraschin, Zenilda L. Bouzon, Éder C. Schmidt
      First page: 560
      Abstract: The photoacclimation responses of the brown macroalga Sargassum cymosum were studied to determine its cytochemical and ultrastructural organization, as well as photosynthetic pigments and performance. S. cymosum was cultivated in three salinities (30, 35 and 40 psu) under four irradiation treatments: PAR‐only, PAR + UVA, PAR + UVB and PAR + UVA + UVB. Plants were exposed to PAR at 70 μmol photons m−2 s−1, PAR + UVB at 0.35 W m−2 and PAR +UVA at 0.70 W m−2 for 3 h per day during 7 days in vitro. Growth rate was not significantly affected by any type of radiation or salinity. The amount of pigments in S. cymosum was significantly influenced by the interaction of salinity and radiation treatments. Compared with PAR‐only, UVR treatments modified the kinetics patterns of the photosynthesis/irradiance curve. After exposure to UVR, S. cymosum increased cell wall thickness and the presence of phenolic compounds. The number of mitochondria increased, whereas the number of chloroplasts showed few changes. Although S. cymosum showed insensitivity to changes in salinity, it can be concluded that samples treated under four irradiation regimes showed structural changes, which were more evident, but not severe, under PAR + UVB treatment. The figure shows the brown macroalga Sargassum cymosum have protective mechanism against oxidative stress, making defense against UVR more efficient. After exposure to UVR, S. cymosum increased cell wall thickness, physodes and presence of phenolic compounds.
      PubDate: 2014-01-10T02:17:08.163177-05:
      DOI: 10.1111/php.12224
       
  • Photobiological Interactions of Blue Light and Photosynthetic Photon Flux:
           Effects of Monochromatic and Broad‐Spectrum Light Sources
    • Authors: Kevin R. Cope; M. Chase Snowden, Bruce Bugbee
      First page: 574
      Abstract: Photosynthesis (Pn) and photomorphogenesis (Pm) are affected by light quality, light intensity and photoperiod. Although blue light (BL) is necessary for normal development, it is less efficient in driving Pn than other wavelengths of photosynthetically active radiation. The effects of BL on Pm are highly species dependent. Here we report the interacting effects of BL and photosynthetic photon flux (PPF) on growth and development of lettuce, radish and pepper. We used light‐emitting diode (LED) arrays to provide BL fractions from 11% to 28% under broad‐spectrum white LEDs, and from 0.3% to 92% under monochromatic LEDs. All treatments were replicated three times at each of two PPFs (200 and 500 μmol m−2 s−1). Other than light quality, environmental conditions were uniformly maintained across chambers. Regardless of PPF, BL was necessary to prevent shade‐avoidance responses in radish and lettuce. For lettuce and radish, increasing BL reduced stem length, and for both species, there were significant interactions of BL with PPF for leaf expansion. Increasing BL reduced petiole length in radish and flower number in pepper. BL minimally affected pepper growth and other developmental parameters. Pepper seedlings were more photobiologically sensitive than older plants. Surprisingly, there were few interactions between monochromatic and broad‐spectrum light sources. Blue light (BL) has profound effects on leaf expansion and stem elongation but the interactions of BL with other wavelengths of photosynthetically active radiation and with total PPF are poorly characterized. We used three broad‐spectrum and four monochromatic LED arrays at two photosynthetic photon flux (PPF) to quantify BL effects on plant growth and development. Regardless of PPF, BL was necessary to prevent shade‐avoidance responses in lettuce and radish but not pepper. Leaf expansion was altered by a unique interaction of BL with PPF. Surprisingly, there were few additional interactions of BL between monochromatic and broad‐spectrum light sources.
      PubDate: 2014-01-18T00:02:47.093904-05:
      DOI: 10.1111/php.12233
       
  • Synthesis and Characterization of Near‐Infrared Absorbing Water
           Soluble Squaraines and Study of their Photodynamic Effects in DLA Live
           Cells
    • Authors: Kulathinte M. Shafeekh; Mohanannair S. Soumya, Moochikkadavath A. Rahim, Annie Abraham, Suresh Das
      First page: 585
      Abstract: Here, we report the synthesis, photophysical properties and photodynamic effects in DLA live cells of three water soluble squaraine dyes, viz. bisbenzothiazolium squaraine dyes SQMI and SQDI with iodine in one and both benzothiazolium units, respectively, and an unsymmetrical squaraine dye ASQI containing iodinated benzothiazolium and aniline substituents. The diiodinated SQDI showed an anomalous trend in both fluorescence and triplet quantum yields over the monoiodinated SQMI, with SQDI showing higher fluorescence and lower triplet quantum yields compared to SQMI. Nanosecond laser flash photolysis of SQDI and SQMI indicated the formation of triplet excited states with quantum yield of 0.19 and 0.26, respectively. On photoirradiation, both the SQDI and SQMI generate singlet oxygen and it was observed that both dyes undergoing oxidation reactions with the singlet oxygen generated. ASQI which exhibited a lower triplet quantum yield of 0.06 was, however, stable and did not react with the singlet oxygen generated. In vitro cytotoxicity studies of these dyes in DLA live cells were performed using Trypan blue dye exclusion method and it reflect an order of cytotoxicity of SQDI>SQMI>ASQI. Intracellular generation of the ROS was confirmed by dichlorofluorescein assay after the in vitro PDT. Synthesis, photophysical properties and photodynamic effects in DLA live cells of three water soluble squaraine dyes, SQDI, SQMI and ASQI, are presented. On photoirradiation, both the SQDI and SQMI generate singlet oxygen where both the dyes undergoing oxidation reactions with the singlet oxygen generated, whereas ASQI was stable and did not react with the singlet oxygen. In vitro cytotoxicity studies of these dyes in DLA cells were performed using Trypan blue dye exclusion method and intracellular generation of ROS was confirmed using dichlorofluorescein assay after the in vitro PDT.
      PubDate: 2014-02-17T07:34:19.222546-05:
      DOI: 10.1111/php.12236
       
  • Photodamage in a Mitochondrial Membrane Model Modulated by the Topology of
           Cationic and Anionic Meso‐Tetrakis Porphyrin Free Bases
    • Authors: Cintia Kawai; Juliana C. Araújo-Chaves, Taciana Magrini, Camila O. C. C. Sanches, Sandra M. S. Pinto, Herculano Martinho, Nasser Daghastanli, Iseli L. Nantes
      First page: 596
      Abstract: The photodynamic effects of the cationic TMPyP (meso‐tetrakis [N‐methyl‐4‐pyridyl]porphyrin) and the anionic TPPS4 (meso‐tetrakis[4‐sulfonatophenyl]porphyrin) against PC/CL phosphatidylcholine/cardiolipin (85/15%) membranes were probed to address the influence of phorphyrin binding on lipid damage. Electronic absorption spectroscopy and zeta potential measurements demonstrated that only TMPyP binds to PC/CL large unilamellar vesicles (LUVs). The photodamage after irradiation with visible light was analyzed by dosages of lipid peroxides (LOOH) and thiobarbituric reactive substance and by a contrast phase image of the giant unilamellar vesicles (GUVs). Damage to LUVs and GUVs promoted by TMPyP and TPPS4 were qualitatively and quantitatively different. The cationic porphyrin promoted damage more extensive and faster. The increase in LOOH was higher in the presence of D2O, and was impaired by sodium azide and sorbic acid. The effect of D2O was higher for TPPS4 as the photosensitizer. The use of DCFH demonstrated that liposomes prevent the photobleaching of TMPyP. The results are consistent with a more stable TMPyP that generates long‐lived singlet oxygen preferentially partitioned in the bilayer. Conversely, TPPS4 generates singlet oxygen in the bulk whose lifetime is increased in D2O. Therefore, the affinity of the porphyrin to the membrane modulates the rate, type and degree of lipid damage. TMPyP binds to the liposome and generates singlet oxygen from molecular oxygen dissolved into bilayer. TPPS4 transfers electronic excitation to bulk molecular oxygen and generates singlet oxygen that travels through solution and attacks a distant lipid bilayer.
      PubDate: 2014-01-23T07:10:06.03687-05:0
      DOI: 10.1111/php.12228
       
  • Inactivation of Bacillus subtilis Spores Using Various Combinations of
           Ultraviolet Treatment with Addition of Hydrogen Peroxide
    • Authors: Yiqing Zhang; Lingling Zhou, Yongji Zhang, Chaoqun Tan
      First page: 609
      Abstract: This study aims at comparing the inactivation of Bacillus subtilis spores by various combinations of UV treatment and hydrogen peroxide (H2O2) addition. The combinations included sequential (UV–H2O2, H2O2–UV) and simultaneous (UV/H2O2) processes. Results showed that B. subtilis spores achieved a certain inactivation effect through UV treatment. However, hardly any inactivation effect by H2O2 alone was observed. H2O2 had a significant synergetic effect when combined with UV treatment, while high irradiance and H2O2 concentration both favored the reaction. When treated with 0.60 mm H2O2 and 113.0 μW/cm2 UV irradiance for 6 min, the simultaneous UV/H2O2 treatment showed significantly improved disinfection effect (4.13 log) compared to that of UV–H2O2 (3.03 log) and H2O2–UV (2.88 log). The relationship between the inactivation effect and the exposure time followed a typical pseudo‐first‐order kinetics model. The pseudo‐first‐order rate constants were 0.478, 0.447 and 0.634 min−1, for the UV‐H2O2, H2O2–UV and UV/H2O2 processes, respectively, further confirming the optimal disinfection effect of the UV/H2O2 process. The disinfection could be ascribed to the OH radicals, as verified by the level of para‐chlorobenzoic acid (pCBA). The facility used in the experiments was a collimated beam apparatus containing a low‐pressure mercury lamp. Petri dishes (90 mm diameter) with 40 mL samples were exposed to the UV in the collimated beam apparatus and stirred gently by a magnetic stirring apparatus. The inactivation of Bacillus subtilis spores of various combinations of UV treatment and H2O2 addition were compared, including sequential (UV‐H2O2, H2O2–UV) and simultaneous (UV/H2O2) processes.
      PubDate: 2014-01-21T23:34:16.851982-05:
      DOI: 10.1111/php.12210
       
  • Role of Ozone in UV‐C Disinfection, Demonstrated by Comparison
           between Wild‐Type and Mutant Conidia of Aspergillus niger
    • Authors: Jing Liu; Lin Zhou, Ji-Hong Chen, Wang Mao, Wen-Jian Li, Wei Hu, Shu-Yang Wang, Chun-Ming Wang
      First page: 615
      Abstract: This study aimed to investigate the tolerance of a melanized wild‐type strain of Aspergillus niger (CON1) and its light‐colored mutant (MUT1) to UV–C light and the concomitantly generated ozone. Treatments were segregated into four groups based on whether UV irradiation was used and the presence or absence of ozone: (−UV, −O3), (−UV, +O3), (+UV, −O3) and (+UV, +O3). The survival of CON1 and MUT1 conidia under +UV decreased as the exposure time increased, with CON1 showing greater resistance to UV irradiation than MUT1. Ozone induced CON1 conidium inactivation only under conditions of UV radiation exposure. While, the inactivation effect of ozone on MUT1 was always detectable regardless of the presence of UV irradiation. Furthermore, the CON1 conidial suspension showed lower UV light transmission than MUT1 when examined at the same concentration. Compared with the pigment in MUT1, the melanin in CON1 exhibited more potent radical‐scavenging activity and stronger UV absorbance. These results suggested that melanin protected A. niger against UV disinfection via UV screening and free radical scavenging. The process by which UV–C disinfection induces a continual decrease in conidial survival suggests that UV irradiation and ozone exert a synergistic fungicidal effect on A. niger prior to reaching a plateau. The effect of UV light was divided into two parts: UV irradiation and the concomitantly generated ozone. The role of ozone in the disinfection of UV–C was illustrated through comparing wild‐type (CON1) and mutant (MUT1) Aspergillus niger conidia. The results indicated that melanin protected A. niger against UV disinfection in two ways: absorbing UV light (UV screening) and scavenging free radicals. The synergistic effect of UV irradiation and ozone exhibited the most potent fungicidal results. So the direct exposure to UV irradiation and ozone were both necessary for thorough disinfection.
      PubDate: 2014-01-07T00:57:14.202179-05:
      DOI: 10.1111/php.12217
       
  • Inactivation of Bacteriophage Infecting Bacteroides Strain GB124 Using
           UV‐B Radiation
    • Authors: David Diston; James E. Ebdon, Huw D. Taylor
      First page: 622
      Abstract: Ultraviolet‐B radiation (280–320 nm) has long been associated with the inactivation of microorganisms in the natural environment. Determination of the environmental inactivation kinetics of specific indicator organisms [used as tools in the field of microbial source tracking (MST)] is fundamental to their successful deployment, particularly in geographic regions subject to high levels of solar radiation. Phage infecting Bacteroides fragilis host strain GB124 (B124 phage) have been demonstrated to be highly specific indicators of human fecal contamination, but to date, little is known about their susceptibility to UV‐B radiation. Therefore, B124 phage (n = 7) isolated from municipal wastewater effluent, were irradiated in a controlled laboratory environment using UV‐B collimated beam experiments. All B124 phage suspensions possessed highly similar first order log‐linear inactivation profiles and the mean fluence required to inactivate phage by 4 − log10 was 320 mJ cm−2. These findings suggest that phage infecting GB124 are likely to be inactivated when exposed to the levels of UV‐B solar radiation experienced in a variety of environmental settings. As such, this may limit the utility of such methods for determining more remote inputs of fecal contamination in areas subject to high levels of solar radiation. Bacteriophage infecting Bacteroides fragilis strain GB‐124 are a useful tool in determining the source of fecal pollution within aquatic environments. Here we present insights into the UV‐B inactivation ecology of this important phage group by conducting controlled laboratory collimated‐beam UV‐B irradiation experiments. Results indicate that B124 phage may be inactivated at levels of UV‐B commonly recorded in the environment, and inactivation potential should be considered when interpreting environmental B124 phage data.
      PubDate: 2014-01-10T02:16:48.971796-05:
      DOI: 10.1111/php.12223
       
  • Novel Porphyrazine Derivatives show Promise for Photodynamic Therapy
           despite Restrictions in Hydrophilicity
    • Authors: Tamarisk K. Horne; Marianne J. Cronjé
      First page: 648
      Abstract: Complexing of ligands to photosensitizers (Ps) has gained popularity by enhancing solubility, cell‐surface recognition and tissue specificity for applications in Photodynamic Therapy (PDT) and fluorescence‐based diagnostics. Here we report on nine carbohydrate‐functionalized porphyrazine (Pz‐galactopyranose/methyl‐ribose) derivatives bearing either H2, Zn(II) or Ni(II) cores for potential use in PDT. Derivatives proved soluble only in organic solvents; dichloromethane (DCM) and tetrahydrofuran (THF). Derivatives were subsequently solubilized using DCM‐based PEG‐DSPE5000‐PBS encapsulation for biological studies due to THF cytotoxicity. Absorption spectra analyses viewed no correlation between core ion, carbohydrate type and peripheral position though encapsulation efficiency (%EE) followed a general order of Zn(II) (60–92%) > H2 (5–34%) > Ni(II) (4–21%). As such, phototoxicity of Zn(II)Pz derivatives were far superior to H2Pz and Ni(II)Pz counterparts following 631.4 nm excitation of MCF‐7 breast cancer cells. Variation was attributed to persistent aggregation and low %EE when regarding the absorption properties recorded. It is therefore believed that revision of the encapsulation method for H2Pz and Ni(II)Pz derivatives would render improved phototoxicity. Zn(II)Pz derivatives show promise as agents for PDT of cancer. Complexing of ligands to photosensitizers (Ps) can enhance solubility, cell‐surface recognition and tissue specificity for applications in Photodynamic Therapy (PDT). Nine carbohydrate‐functionalized porphyrazine (Pz‐galactopyranose/methyl‐ribose) derivatives with H2, Zn(II) or Ni(II) cores were analyzed for potential use in PDT. Derivatives solubilized in DCM and tetrahydrofuran were cytotoxic; encapsulation in DCM‐based PEG‐DSPE5000‐PBS was biologically suitable. No correlation between core ion, carbohydrate type and peripheral position was revealed via absorption spectra analyses. Encapsulation efficiency (%EE): Zn(II) (60–92%) > H2 (5–34%) > Ni(II) (4–21%). Phototoxicity of Zn(II)Pz derivatives showed highest efficiency following excitation in MCF‐7 cells, and show promise as anticancer PDT agents.
      PubDate: 2014-01-21T23:34:12.207309-05:
      DOI: 10.1111/php.12231
       
  • Photosensitive and Biomimetic Core–Shell Nanofibrous Scaffolds as
           Wound Dressing
    • Authors: Guorui Jin; Molamma P. Prabhakaran, Seeram Ramakrishna
      First page: 673
      Abstract: Tissue engineered skin grafts that mimic the native extracellular matrix of skin has gained huge popularity among clinicians since they increase the survival rate of the patients. Phototherapy shows promising results with respect to acute and chronic pain relief, treatment of inflammatory conditions and promotion of wound healing. Here, we encapsulated a photosensitive polymer poly (3‐hexylthiophene) (P3HT) and epidermal growth factor in the core–shell‐structured Gelatin/poly(L‐lactic acid)‐co‐poly‐(ε‐caprolactone) nanofibers [Gel/PLLCL/P3GF(cs)] by coaxial spinning and studied the potential application of the Gel/PLLCL/P3GF(cs) nanofibrous scaffold as a novel skin graft. The proliferation of fibroblasts was significantly improved on Gel/PLLCL/P3GF(cs) under light stimulation compared to fibroblasts on the same scaffold under dark condition. Studies on the in vitro wound healing ability of Gel/PLLCL/P3GF(cs) showed complete closure of wound after 9 days under “light stimulation” too. Furthermore, the potential of adipose‐derived stem cells (ASCs) to differentiate to epidermal cells on Gel/PLLCL/P3GF(cs) was evaluated. The differentiated ASCs with keratinocytes morphology were only found on the light stimulated Gel/PLLCL/P3GF(cs). Our results suggest that the photosensitive core–shell Gel/PLLCL/P3GF(cs) nanofibers could be a novel substrate to aid in the reestablishment of skin architecture. A photosensitive polymer, namely, poly (3‐hexylthiophene) is encapsulated within the core–shell‐structured Gel/PLLCL fibers by coaxial electrospinning. The proliferation of human dermal fibroblasts was significantly improved on the core–shell nanofibers under light stimulation compared to fibroblasts on the same scaffold under nonstimulated condition. Moreover, the stem cells on the photosensitive scaffolds under light stimulation were more likely to differentiate into epidermal lineages compared to cells without stimulation. Our results suggest that the photosensitive core–shell nanofibers can serve as a novel substrate to promote skin regeneration.
      PubDate: 2014-02-04T07:19:25.762274-05:
      DOI: 10.1111/php.12238
       
  • Early Diagnosis of Colorectal Cancer in Rats With DMH Induced
           Carcinogenesis by Means of Urine Autofluorescence Analysis
    • Authors: Zuzana Šteffeková; Anna Birková, Alojz Bomba, Mária Mareková
      First page: 682
      Abstract: Cancer is one of the most highlighted topics of current research. Early detection of this disease allows more effective therapy, hence higher chance of cure. Application of fluorescence spectral techniques into oncological diagnostic is one of the potential alternatives. Chemically induced carcinogenesis in rats is widely used model for exploration of various aspects of colorectal cancer. This study shows value of discriminate analysis of urine fluorescent fingerprint between healthy control group of rats and those with dimethylhydrazine induced early lesions of colorectal cancer. Using fluorescence spectroscopy, significant difference (P 
      PubDate: 2014-02-15T08:55:50.64025-05:0
      DOI: 10.1111/php.12240
       
  • Practical Labeling Methodology for Choline‐Derived Lipids and
           Applications in Live Cell Fluorescence Imaging
    • Authors: Caishun Li; Jessie A. Key, Feng Jia, Arpan Dandapat, Soo Hur, Christopher W. Cairo
      First page: 686
      Abstract: Lipids of the plasma membrane participate in a variety of biological processes, and methods to probe their function and cellular location are essential to understanding biochemical mechanisms. Previous reports have established that phosphocholine‐containing lipids can be labeled by alkyne groups through metabolic incorporation. Herein, we have tested alkyne, azide and ketone‐containing derivatives of choline as metabolic labels of choline‐containing lipids in cells. We also show that 17‐octadecynoic acid can be used as a complementary metabolic label for lipid acyl chains. We provide methods for the synthesis of cyanine‐based dyes that are reactive with alkyne, azide and ketone metabolic labels. Using an improved method for fluorophore conjugation to azide or alkyne‐modified lipids by Cu(I)‐catalyzed azide‐alkyne cycloaddition (CuAAC), we apply this methodology in cells. Lipid‐labeled cell membranes were then interrogated using flow cytometry and fluorescence microscopy. Furthermore, we explored the utility of this labeling strategy for use in live cell experiments. We demonstrate measurements of lipid dynamics (lateral mobility) by fluorescence photobleaching recovery (FPR). In addition, we show that adhesion of cells to specific surfaces can be accomplished by chemically linking membrane lipids to a functionalized surface. The strategies described provide robust methods for introducing bioorthogonal labels into native lipids. Fluorescent probes can be used to investigate the structure and dynamics of the plasma membrane. Exogenous fluorescent lipid probes which integrate into the membrane are often used for this purpose. In this study, we investigate the utility of metabolic labeling of phosphocholine‐derived lipids for introducing fluorescent probes. Using synthetic fluorophores that react with bioorthogonal metabolic labels, we labeled live cell membranes. We demonstrate that these labeled lipids can be used for a variety of applications including imaging, measurement of lipid dynamics (lateral diffusion) and chemical adhesion of the cells to reactive surfaces.
      PubDate: 2014-01-31T07:25:27.211779-05:
      DOI: 10.1111/php.12234
       
  • Effect of Light on Expression of Clock Genes in Xenopus laevis
           Melanophores
    • Authors: Maria Nathália de Carvalho Magalhães Moraes; Maristela Oliveira Poletini, Bruno Cesar Ribeiro Ramos, Leonardo Henrique Ribeiro Graciani Lima, Ana Maria Lauro Castrucci
      First page: 696
      Abstract: Light–dark cycles are considered important cues to entrain biological clocks. A feedback loop of clock gene transcription and translation is the molecular basis underlying the mechanism of both central and peripheral clocks. Xenopus laevis embryonic melanophores respond to light with melanin granule dispersion, response possibly mediated by the photopigment melanopsin. To test whether light modulates clock gene expression in Xenopus melanophores, we used qPCR to evaluate the relative mRNA levels of Per1, Per2, Clock and Bmal1 in cultured melanophores exposed to light–dark (LD) cycle or constant darkness (DD). LD cycles elicited temporal changes in the expression of Per1, Per2 and Bmal1. A 10‐min pulse of blue light was able to increases the expression of Per1 and Per2. Red light had no effect on the expression of these clock genes. These data suggest the participation of a blue‐wavelength sensitive pigment in the light–dark cycle‐mediated oscillation of the endogenous clock. Our results add an important contribution to the emerging field of peripheral clocks, which in nonmammalian vertebrates have been mostly studied in Drosophila and Danio rerio. Within this context, we show that X. laevis melanophores, which have already led to melanopsin discovery, represent an ideal model to understanding circadian rhythms. In light‐sensitive cells, environmental light may be transduced through melanopsins (pigment excited by short wavelength) which, in turn, regulates the machinery of endogenous molecular clock through an increase in Per1 expression. In a nonmammalian vertebrate cell line (X. laevis melanophore), we demonstrated that a blue‐light pulse increases Per1 and Per2 expression, and that Per1 gene expression oscillates in a circadian fashion under light–dark cycle. Thus, these cells are a promising model to investigate the biological mechanisms involved in photoentrainment in peripheral clocks.
      PubDate: 2014-01-18T00:03:00.309864-05:
      DOI: 10.1111/php.12230
       
  • Biochemical Composition and Antioxidant Properties of Lavandula
           angustifolia Miller Essential Oil are Shielded by Propolis Against UV
           Radiations
    • Authors: Gismondi Angelo; Canuti Lorena, Grispo Marta, Canini Antonella
      First page: 702
      Abstract: UV radiations are principal causes of skin cancer and aging. Suntan creams were developed to protect epidermis and derma layers against photodegradation and photooxidation. The addition of antioxidant plant extracts (i.e. essential oil) to sunscreens is habitually performed, to increase their UV protective effects and to contrast pro‐radical and cytotoxic compounds present in these solutions. According to these observations, in the present work, the alteration of chemical composition and bioactive properties of Lavandula angustifolia Miller essential oil, exposed to UV light, was investigated. UV induced a significant deterioration of lavender oil biochemical profile. Moreover, the antioxidant activity of this solution, in in vitro tests and directly on B16‐F10 melanoma cells, greatly decreased after UV treatment. Our results also showed that essential oil was shielded from UV stress by propolis addition. Even after UV treatment, bee glue highly protected lavender oil secondary metabolites from degradation and also preserved their antiradical properties, both in in vitro antioxidant assays and in cell oxidative damage evaluations. This research proposed propolis as highly efficient UV protective and antiradical additive for sunscreens, cosmetics and alimentary or pharmaceutical products containing plant extracts. Propolis shields Lavandula angustifolia Miller essential oil from UV‐induced photodegradation. Lavender biochemical components are strongly degraded by UV radiations and consequently their antioxidant properties, in in vitro assays and directly on B16F10 cells, are decreased. Propolis is proposed as highly efficient UV protective and antiradical additive for sunscreens, cosmetics and alimentary or pharmaceutical products containing plant extracts.
      PubDate: 2014-01-28T00:35:47.933065-05:
      DOI: 10.1111/php.12229
       
  • Photosensitized Damage Inflicted on Plasma Membranes of Live Cells by An
           Extracellular Generator of Singlet Oxygen—A Linear Dependence of A
           Lethal Dose on Light Intensity
    • Authors: Mirosław Zarębski; Magdalena Kordon, Jurek W. Dobrucki
      First page: 709
      Abstract: We describe a study of the influence of a dose rate, i.e. light intensity or photon flux, on the efficiency of induction of a loss of integrity of plasma membranes of live cells in culture. The influence of a photon flux on the size of the light dose, which was capable of causing lethal effects, was measured in an experimental system where singlet oxygen was generated exclusively outside of live cells by ruthenium(II) phenantroline complex. Instantaneous, sensitive detection of a loss of integrity of a plasma membrane was achieved by fluorescence confocal imaging of the entry of this complex into a cell interior. We demonstrate that the size of the lethal dose of light is directly proportional to the intensity of the exciting light. Thus, the probability of a photon of the exciting light inflicting photosensitized damage on plasma membranes diminishes with increasing density of the incident photons. The influence of a dose rate, i.e. light intensity or photon flux, on the efficiency of induction of a photosensitized loss of integrity of plasma membranes of live cells in culture is described. We demonstrate that the size of the lethal dose of light is directly proportional to the intensity of the exciting light. Thus, the probability of a photon of the exciting light inflicting photosensitized damage on plasma membranes diminishes with increasing density of the incident photons.
      PubDate: 2014-01-06T23:58:14.393371-05:
      DOI: 10.1111/php.12216
       
  • Novel Photodynamic Effect of a Psoralen‐Conjugated Oligonucleotide
           for the Discrimination of the Methylation of Cytosine in DNA
    • Authors: Asako Yamayoshi; Yohei Matsuyama, Mikihiko Kushida, Akio Kobori, Akira Murakami
      First page: 716
      Abstract: DNA methylation and demethylation significantly affect the deactivation and activation processes of gene expression significantly. In particular, C‐5‐methylation of cytosine in the CpG islands is important for the epigenetic modification in genes, which plays a key role in regulating gene expression. The determination of the location and frequency of DNA methylation is important for the elucidation of the mechanisms of cell differentiation and carcinogenesis. Here we designed a psoralen‐conjugated oligonucleotide (PS‐oligo) for the discrimination of 5‐methylcytosine (5‐mC) in DNA. The cross‐linking behavior of psoralen derivatives with pyrimidine bases, such as thymine, uracil and cytosine has been well discussed, but there are no reports which have examined whether cross‐linking efficiency of psoralen with cytosine would be changed with or without C‐5 methylation. We found that the cross‐linking efficiency of PS‐oligo with target‐DNA containing 5‐mC was greatly increased compared to the case of target‐DNA without 5‐mC, approximately seven‐fold higher. Here we report a new aspect of the photocross‐linking behavior of psoralen with 5‐mC that is applicable to a simple, sequence‐specific and quantitative analysis for the discrimination of 5‐mC in DNA, which can be applicable to study the epigenetic behavior of gene expressions. We designed a psoralen‐conjugated oligonucleotide (PS‐oligo) for the discrimination of 5‐methylcytosine (5‐mC) in DNA. The cross‐linking behavior of psoralen derivatives with pyrimidine bases, such as thymine, uracil and cytosine has been well discussed, but there are no reports which have examined whether cross‐linking efficiency of psoralen with cytosine would be changed with or without C‐5 methylation. We found that the cross‐linking efficiency of PS‐oligo with target‐DNA containing 5‐mC was greatly increased compared to the case of target‐DNA without 5‐mC, approximately seven‐fold higher.
      PubDate: 2014-01-21T02:58:36.445294-05:
      DOI: 10.1111/php.12232
       
  • Home Lighting Before Usual Bedtime Impacts Circadian Timing: A Field Study
    • Authors: Helen J. Burgess; Thomas A. Molina
      First page: 723
      Abstract: Laboratory studies suggest that evening light before bedtime can suppress melatonin. Here, we measured the range of evening light intensity people can generate with their household lights, and for the first time determined if varying home light before usual bedtime can shift circadian phase. This was a 3‐week study with two counterbalanced conditions separated by a 5‐day break. In a dim week, eight healthy subjects minimized their home light exposure from 4 h before habitual bedtime until a self‐selected bedtime. In a bright week, the subjects maximized their home lighting for the same time. The dim light melatonin onset (DLMO) was assessed after each week. On average subjects maximized their lights to approximately 65 lux and minimized their lights to approximately 3 lux. Wrist actigraphy indicated that subjects went to bed slightly later when lights were maximized (average 14 min later, P = 0.05), but wake time did not change. Every subject had a later DLMO after the week of maximum versus minimum light exposure (average 1:03 h later, P 
      PubDate: 2014-02-07T02:39:33.233476-05:
      DOI: 10.1111/php.12241
       
  • Effect of Light on Expression of Clock Genes in Xenopus laevis
           Melanophores
    • Authors: Maria Nathália Moraes; Maristela Poletini, Bruno Cesar Ribeiro Ramos, Leonardo Henrique Ribeiro Graciani Lima, Ana Maria Castrucci
      Pages: n/a - n/a
      Abstract: Light‐dark cycles are considered important cues to entrain biological clocks. A feedback loop of clock gene transcription and translation is the molecular basis underlying the mechanism of both central and peripheral clocks. Xenopus laevis embryonic melanophores respond to light with melanin granule dispersion, response possibly mediated by the photopigment melanopsin. In order to test whether light modulates clock gene expression in Xenopus melanophores, we used qPCR to evaluate the relative mRNA levels of Per1, Per2, Clock and Bmal1 in cultured melanophores exposed to light‐dark (LD) cycle or constant darkness (DD). LD cycles elicited temporal changes in the expression of Per1, Per2 and Bmal1. A 10‐min pulse of blue light was able to increase the expression of Per1 and Per2. Red light had no effect on the expression of these clock genes. These data suggest the participation of a blue‐wavelength sensitive pigment in the light‐dark cycle‐mediated oscillation of the endogenous clock. Our results add an important contribution to the emerging field of peripheral clocks, which in non‐mammalian vertebrates have been mostly studied in Drosophila and Danio rerio. Within this context, we show that Xenopus laevis melanophores, which have already led to melanopsin discovery, represent an ideal model to understanding circadian rhythms. This article is protected by copyright. All rights reserved.
      PubDate: 2013-12-26T07:09:26.462616-05:
      DOI: 10.1111/j.1751-1097.2013.12230.x
       
  • Energy Harvesting Capability of Lipid‐Merocyanine Macromolecules: A
           New Design and Performance Model Development
    • Authors: Lobat Tayebi; Masoud Mozafari, Rita El-khouri, Parvaneh Rouhani, Daryoosh Vashaee
      First page: 517
      Abstract: Light induced cis/trans isomerization in the family of merocyanine (MC) dyes offers a recyclable proton pumping ability which can potentially be used in hybrid bio‐electronic devices. In this article, a hexadecyl MC dye is embedded in lipid molecules to make a macromolecular configuration of a lipid/hexadecyl MC membrane. Lipid molecules play a critical role in stabilizing the dye in a membrane structure for practical use in energy devices. In this study, we first examined the proton pumping characteristic of the lipid/hexadecyl MC membrane in a conventional photoelectrochemical cell. Next, a major modification in the cell was introduced by eliminating I2/I‐electrolyte which resulted in a two‐fold increase in the open circuit voltage compared with that of the conventional cell. In addition, the charging time in the new cell was reduced approximately four orders of magnitude. This research demonstrated that the newly designed lipid‐ MC cell can act as a promising bioelectronic device based on the green energy of photoinduced MC dye proton pumping. Capacitor charging time reduced and open circuit voltage enhanced significantly in the newly designed lipid‐merocyanine photoelectrochemical cell.
      PubDate: 2013-11-28T05:30:17.088405-05:
      DOI: 10.1111/php.12193
       
  • Kinetics of Photosynthetic Response to Ultraviolet and Photosynthetically
           Active Radiation in Synechococcus WH8102 (CYANOBACTERIA)
    • Authors: Glaucia M. Fragoso; Patrick J. Neale, Todd M. Kana, Alicia L. Pritchard
      First page: 522
      Abstract: The picoplanktonic cyanobacteria, Synechococcus spp., (Nägeli) are important contributors to global ocean primary production that can be stressed by solar radiation, both in the photosynthetically active (PAR) and ultraviolet (UV) range. We studied the responses of PSII quantum yield (active fluorescence), carbon fixation (14C assimilation) and oxygen evolution (membrane inlet mass spectrometry) in Synechococcus WH8102 under moderate UV and PAR. PSII quantum yield decreased during exposure to moderate UV and UV+PAR, with response to the latter being faster (6.4 versus 2.8 min, respectively). Repair processes were also faster when UV+PAR exposure was followed by moderate PAR (1.68 min response time) than when UV was followed by very low PAR (10.5 min response time). For the UV+PAR treatment, the initial decrease in quantum yield was followed by a 50% increase (“rebound”) after 7 min exposure, showing an apparent photoprotection induction. While oxygen uptake increased with PAR, it did not change under UV, suggesting that this oxygen‐dependent mechanism of photoprotection, which may be acting as an electron sink, is not an important strategy against UV. We used propyl gallate, an antioxidant, to test for plastid terminal oxidase (ptox) or ptox‐like enzymes activity, but it caused nonspecific and toxic effects on Synechococcus WH8102. We studied the responses of PSII quantum yield, carbon fixation and oxygen evolution in Synechococcus WH8102 under levels of PAR and UVR that are representative of a mixed layer from oligotrophic waters. Fluorescence kinetics measurements showed that these radiation levels inhibited PSII activity, however, an apparent induction of photoprotection was observed. Although oxygen uptake is a mechanism of photoprotection when cells are exposed to increase levels of PAR, our results show that this is not an important strategy against UVR.
      PubDate: 2013-11-28T02:16:24.934729-05:
      DOI: 10.1111/php.12202
       
  • Photoinhibition of Cyanobacteria and its Application in Cultural Heritage
           Conservation
    • Authors: Paul Hsieh; Jens Z. Pedersen, Laura Bruno
      First page: 533
      Abstract: Light has bilateral effects on phototrophic organisms. As cyanobacteria in Roman hypogea are long acclimatized to dim environment, moderate intensity of illumination can be used to alleviate biodeterioration problems on the stone substrata. Moderate intensity of light inactivates cyanobacteria by causing photoinhibition, photobleaching and photodamage to the cells. The effectiveness of light depends not only on its intensity but also on the composition and pigmentation of the component cyanobacteria in the biofilms. Red light is the most effective for the species rich in phycocyanin and allophycocyanin, such as Leptolyngbya sp. and Scytonema julianum, whereas green light is effective to inhibit the species rich in phycoerythrin, like Oculatella subterranea. White light is effective to control the grayish and the black cyanobacteria, such as Symphyonemopsis sp. and Eucapsis sp. abundant in all of these pigments. Blue light is the least effective. 150 μmol photons m−2 s−1 of blue light cannot cause biofilm damage while the same intensity of red, green or white irradiation for 14 days can severely damage the cyanobacterial cells in the biofilms due to ROS formation. Electron spin resonance spectroscopy detected the formation of radicals in different cyanobacterial cellular extracts exposed to 80 μmol photons m−2 s−1 of light. To our knowledge, we are the first group that applies photoinhibition in the field of cultural heritage conservation. Because cyanobacteria are rich in Chl a and phycobiliproteins that can be excited by light to generate ROS, exposure of cyanobacteria to light beyond the turnover intensity may result in photoinhibition of photosynthesis, photobleaching of pigments and photodamage to the cells. Practically, red, green or white illumination can be tested at night in situ in the dim catacombs, caves and underground chambers, without disturbing the tourists, and without introducing any harmful chemicals to humans, to environment, or to the cultural heritage.
      PubDate: 2013-12-10T01:27:30.02803-05:0
      DOI: 10.1111/php.12208
       
  • Reflectance and Cyclic Electron Flow as an Indicator of Drought Stress in
           Cotton (Gossypium hirsutum)
    • Authors: Ruchi Singh; Jishnu Naskar, Uday V. Pathre, Pramod A. Shirke
      First page: 544
      Abstract: The response and the functioning of the photosynthetic machinery of cotton, Gossypium hirsutum during water stress was studied by leaf optical properties, linear (ETRII) and cyclic electron flow (CEF) and chlorophyll a fluorescence. We observed that in G. hirsutum, during water limitation, Chlorophyll b showed the best correlation with reflectance at 731 nm and is a better indicator of drought. Fv/Fm was observed to be very insensitive to mild water stress. However, during severe water stress the leaves exhibit considerable inhibition in Fv/Fm and an increase in anthocyanin levels by about 20‐fold. CEF was very responsive to mild water stress. The mild drought stress caused large decrease in the ability of the leaves to utilize the light energy. Photosystem I and photosystem II is protected from photoinhibition by high CEF and nonphotochemical quenching under mild water stress. While during severe drought stress, linear electron flow showed a sharp decrease in comparison to CEF. CEF play a major role in G. hirsutum leaves during mild as well as under severe water stress condition and is thus a good indicator of water stress. We observed that in Gossypium hirsutum, during water limitation, Chlorophyll b showed the best correlation with reflectance at 731 nm and is a good indicator of drought. During mild water stress photosystem I and photosystem II is protected from photoinhibition by high cyclic electron flow (CEF) and nonphotochemical quenching. While during severe drought stress, linear electron flow decreases sharply in comparison to CEF. CEF play a major role in G. hirsutum leaves during mild as well as under severe water stresses and is thus a good indicator of drought.
      PubDate: 2013-12-14T00:32:55.516712-05:
      DOI: 10.1111/php.12213
       
  • Scrambled Self‐Assembly of Bacteriochlorophylls c and e in Aqueous
           Triton X‐100 Micelles
    • Authors: Yoshitaka Saga; Tatsuya Saiki, Naoya Takahashi, Yutaka Shibata, Hitoshi Tamiaki
      First page: 552
      Abstract: Bacteriochlorophyll (BChl) e was coassembled with BChl c in Triton X‐100 micelles in aqueous solutions. The Qy absorption bands of the coaggregates were positioned between those of aggregates consisting solely of BChl c or e. The electronic absorption spectra of the coaggregates could not be reproduced by linear combinations of the spectra of the aggregates consisting solely of each pigment, but they were in line with the simulated spectra for the self‐aggregates in which both BChls were randomly distributed. These suggest that BChls c and e are not spatially separated; they are homogenously distributed over the self‐aggregates to give electronic spectra that are different from those of the aggregate consisting solely of each pigment. Deaggregation of the scrambled self‐aggregates by excess Triton X‐100 did not produce any spectral components assigned to an aggregate consisting solely of either BChl c or e. Acid‐induced decomposition of the scrambled aggregates showed different kinetics from those of the aggregates consisting solely of each pigment. These also support the homogeneous distribution of BChls c and e in the scrambled self‐aggregates. These results will be useful to investigate the major light‐harvesting antenna systems of green photosynthetic bacteria that contain two kinds of chlorosomal BChls. Bacteriochlorophyll (BChl) e was coassembled with BChl c in Triton X‐100 micelles in aqueous solutions. The spectral features and the decomposition behaviors of the scrambled self‐aggregates suggest that BChls c and e are not spatially separated; they are homogenously distributed over the self‐aggregates to give electronic spectra that are different from those of the aggregate consisting solely of each pigment.
      PubDate: 2013-12-24T00:48:46.567288-05:
      DOI: 10.1111/php.12219
       
  • Antimicrobial Photodynamic Efficiency of Novel Cationic Porphyrins towards
           Periodontal Gram‐positive and Gram‐negative Pathogenic
           Bacteria
    • Authors: Chandra Sekhar Prasanth; Suneesh C. Karunakaran, Albish K. Paul, Vesselin Kussovski, Vanya Mantareva, Danaboyina Ramaiah, Leslie Selvaraj, Ivan Angelov, Latchezar Avramov, Krishnankutty Nandakumar, Narayanan Subhash
      First page: 628
      Abstract: The Gram‐negative Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum are major causative agents of aggressive periodontal disease. Due to increase in the number of antibiotic‐resistant bacteria, antimicrobial Photodynamic therapy (aPDT) seems to be a plausible alternative. In this work, photosensitization was performed on Gram‐positive and Gram‐negative bacteria in pure culture using new‐age cationic porphyrins, namely mesoimidazolium‐substituted porphyrin derivative (ImP) and pyridinium‐substituted porphyrin derivative (PyP). The photophysical properties of both the sensitizers including absorption, fluorescence emission, quantum yields of the triplet excited states and singlet oxygen generation efficiencies were evaluated in the context of aPDT application. The studied porphyrins exhibited high ability to accumulate into bacterial cells with complete penetration into early stage biofilms. As compared with ImP, PyP was found to be more effective for photoinactivation of bacterial strains associated with periodontitis, without any signs of dark toxicity, owing to its high photocytotoxicity. We describe the synthesis and in vitro photodyanamic activity of two cationic porphyrin derivatives using Gram‐positive as well as Gram‐negative bacteria. These porphyrin derivatives exhibited favorable photophysical properties including high quantum yields of the triplet excited state and singlet oxygen generation efficiency. Furthermore, the in vitro studies indicated that these derivatives accumulate into bacterial cells and biofilms, and exhibit high antibacterial activity upon NIR excitation. Our results demonstrate that these cationic porphyrins can act as sensitizers for effective photoinactivation of bacterial strains associated with periodontitis and thereby their potential application in antibacterial photodynamic therapy.
      PubDate: 2013-12-17T00:05:41.069563-05:
      DOI: 10.1111/php.12198
       
  • Hydrogel‐Forming and Dissolving Microneedles for Enhanced Delivery
           of Photosensitizers and Precursors
    • Authors: Ryan F. Donnelly; Desmond I. J. Morrow, Maelíosa T. C. McCrudden, Ahlam Zaid Alkilani, Eva M. Vicente-Pérez, Conor O'Mahony, Patricia González-Vázquez, Paul A. McCarron, A. David Woolfson
      First page: 641
      Abstract: We present “one‐step application” dissolving and hydrogel‐forming microneedle arrays (MN) for enhanced delivery of photosensitizers/precursors. MN (280 μm) prepared from 20% w/w poly(methylvinylether/maelic acid) and cross‐linked with glycerol by esterification to form hydrogels upon skin insertion, or allowed to dissolve rapidly in skin, were combined with patches containing 19 mg cm−2 of 5‐aminolevulinic acid (ALA) or meso‐tetra (N‐methyl‐4‐pyridyl) porphine tetra tosylate (TMP) for drug delivery. Both MN types were mechanically robust, with compression forces of 20.0 N only causing height reductions of 14%. Application forces as low as 8.0 N per array allowed>95% of the MN in each array type to penetrate excised porcine skin, with the MN penetrating to approximately 220 μm. MN significantly enhanced transdermal delivery of ALA and TMP in vitro, with the hydrogel‐forming system comparable with the dissolving system for ALA delivery (approximately 3000 nmol cm−2 over 6 h), but superior for delivery of the much larger TMP molecule (approximately 14 nmol cm−2 over 24 h, compared to 0.15 nmol cm−2). As this technology clearly has potential in enhanced photodynamic therapy of neoplastic skin lesions, we are currently planning animal studies, to be followed by preliminary human evaluations. GMP manufacturing scale‐up is ongoing. We present novel dissolving and hydrogel‐forming microneedle arrays (MN) that can be applied in a one‐step fashion and are intended to enhance delivery of photosensitizers and photosensitizer precursors. Both dissolving and hydrogel‐forming MN proved effective in in vitro studies and we are now proceeding with animal investigations prior to preliminary human evaluation of technology with the potential to improve therapeutic outcomes for patients with nodular skin lesions.
      PubDate: 2013-12-05T05:49:06.191193-05:
      DOI: 10.1111/php.12209
       
  • Gold Nanorod‐Assembled PEGylated Graphene‐Oxide Nanocomposites
           for Photothermal Cancer Therapy
    • Authors: Uuriintuya Dembereldorj; Seon Young Choi, Erdene-Ochir Ganbold, Nam Woong Song, Doseok Kim, Jaebum Choo, So Yeong Lee, Sehun Kim, Sang-Woo Joo
      First page: 659
      Abstract: Gold nanorod‐attached PEGylated graphene‐oxide (AuNR‐PEG‐GO) nanocomposites were tested for a photothermal platform both in vitro and in vivo. Cytotoxicity of AuNR was reduced after encapsulation with PEG‐GO along with the removal of cetyltrimethylammonium bromide (CTAB) from AuNR by HCl treatment. Cellular internalization of the CTAB‐eliminated AuNR‐PEG‐GO nanocomposites was examined using dark‐field microscopy (DFM), confocal Raman microscopy and transmission electron microscopy (TEM). To determine the photothermal effect of the AuNR‐PEG‐GO nanocomposites, A431 epidermoid carcinoma cells were irradiated with Xe‐lamp light (60 W cm−2) for 5 min after treatment with the AuNR‐PEG‐GO nanocomposites for 24 h. Cell viability significantly decreased by ~40% when the AuNR‐PEG‐GO‐encapsulated nanocomposites were irradiated with light as compared with the cells treated with only the AuNR‐PEG‐GO nanocomposites without any illumination. In vivo tumor experiments also indicated that HCl‐treated AuNR‐PEG‐GO nanocomposites might efficiently reduce tumor volumes via photothermal processes. Our graphene and AuNR nanocomposites will be useful for an effective photothermal therapy. Gold nanorod‐attached PEGylated graphene‐oxide nanocomposites were tested for a photothermal platform both in vitro and in vivo.
      PubDate: 2013-12-05T05:49:34.47705-05:0
      DOI: 10.1111/php.12212
       
  • Effect of Laser Phototherapy on Enzymatic Activity of Salivary Glands of
           Hamsters Treated with 5‐Fluorouracil
    • Authors: Luana Campos; José Nicolau, Victor E. Arana-Chavez, Alyne Simões
      First page: 667
      Abstract: The chemotherapeutic agent 5‐Fluorouracil (5‐FU) can induce salivary gland hypofunction (SGH); however, previous studies did not reach final conclusions on the influence of this drug on glandular tissue. Thus, the aim of this study was to investigate the effect of 5‐FU on submandibular (SMs) and sublingual glands (SLs), as well as, the effect of laser phototherapy (LPT) on SGH induced by 5‐FU. Eighty‐five hamsters were divided into three groups: control (C), chemotherapy (CT) and laser (L), and the SGH was induced by two injections of 5‐FU in groups CT and L. The irradiation was performed using a diode (λ780 nm/20 mW/5 J cm−2/0.2 J and 10 s per point/spot size of 0.04 cm2) and applied daily. On the euthanasia day, SMs and SLs were removed and biochemical analyses were carried out. The lactate dehydrogenase activity was increased in group CT when compared with group C for SLs and SMs (P 
      PubDate: 2013-11-28T05:30:25.473088-05:
      DOI: 10.1111/php.12195
       
 
 
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