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Photochemistry and Photobiology

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https://www.readbyqxmd.com/read/28513845/claud-s-rupert-1919-2017-the-father-of-dna-repair
#1
Aziz Sancar
Claud Stanley Rupert Jr, a founding father of the field of DNA repair, died of natural causes in Dallas, Texas, on February 2(nd) , 2017. Dr. Rupert was highly respected by the photobiology and DNA repair communities. In 1964, he received the Finsen Medal, the highest recognition given by International Union of Photobiology. He was elected to the American Association for the Advancement of Science in 1966. In 1971, he was named to the Johns Hopkins University Society of Scholars. This article is protected by copyright...
May 17, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28510321/novel-zns-carbon-nanofibers-photocatalyst-for-degradation-of-rhodamine-6g-kinetics-tracking-of-operational-parameters-and-development-of-a-kinetics-model
#2
Ali Mehrizad, Parvin Gharbani
A novel nanocomposite in the role of photocatalyst was prepared by composition of zinc sulfide (ZnS) nanoparticles with carbon nanofibers (CNFs) and was characterized. The XRD, EDX, and FE-SEM analysis revealed that ZnS is successfully embedded in CNFs matrix. The DRS results indicated that supporting of ZnS by CNFs led to a decrease of the band gap energy. The photocatalytic degradation of a hazardous xanthine dye, Rhodamine 6 G (Rh-6G), by the prepared ZnS/CNFs composite was examined from the kinetics point of view...
May 16, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28503778/a-topical-zinc-ionophore-blocks-tumorigenic-progression-in-uv-exposed-skh-1-high-risk-mouse-skin
#3
Rebecca Justiniano, Jessica Perer, Anh Hua, Mohammad Fazel, Andrea Krajisnik, Christopher M Cabello, Georg T Wondrak
Nonmelanoma skin cancer (NMSC) is the most common malignancy in the United States representing a considerable public health burden. Pharmacological suppression of skin photo-carcinogenesis has shown promise in preclinical and clinical studies, but more efficacious photochemopreventive agents are needed. Here, we tested feasibility of harnessing pharmacological disruption of intracellular zinc-homeostasis for photochemoprevention in vitro and in vivo. Employing the zinc-ionophore and FDA-approved microbicidal agent zinc pyrithione (ZnPT), used worldwide in over-the-counter (OTC) topical consumer products, we first demonstrated feasibility of achieving ZnPT-based intracellular Zn(2+) -overload in cultured malignant keratinocytes (HaCaT-ras II-4; SCC-25) employing membrane-permeable fluorescent probes...
May 15, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28503745/interactions-between-phyb-and-pif-proteins-alter-thermal-reversion-reactions-in-vitro
#4
Robert W Smith, Britta Helwig, Adrie H Westphal, Eran Pel, Jan Willem Borst, Christian Fleck
The dynamic behaviour of the plant red/far-red light photoreceptor phytochrome B (phyB) has been elucidated in natural and synthetic systems. Red light switches phyB from the inactive Pr state to the active Pfr state, a process that is reversed by far-red light. Alongside light signals, phyB activity is constrained by thermal reversion (that is prominent in the dark) and protein-protein interactions between phyB, other phytochrome molecules, and, among others, PHYTOCHROME INTERACTING FACTORs (PIFs). Requirements for phyB-PIF association have been well studied and are central to light-regulated synthetic tools...
May 15, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28477379/tolyporphin-an-unusual-green-chlorin-like-dioxobacteriochlorin
#5
Christian Brückner
The tolyporphins, a family of green tetrapyrrolic pigments isolated from a cyanobacterium-microbial ecological unit, possess unique carbohydrate-derivatized dioxobacteriochlorin frameworks. A brief overview over the history, synthesis, chemistry, and biological properties of the tolyporphins form the backdrop for highlighting the contribution by Hood et al. [Hood, D., D. M. Niedzwiedzki, R. Zhang, Y. Zhang, J. Dai, E. S. Miller, D. F. Bocian, P. G. Williams, J. S. Lindsey and D. Holten (2017) Photochem. Photobiol...
May 6, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28477352/study-on-the-basic-performance-of-three-phase-fluidized-bed-equipment-for-solar-photocatalysis-membrane-separation
#6
Li Sha, Liping Xie, Miaomiao Li, Xuening Fei, Jinshan Du, Chenxi Zou
In this study, three-phase fluidized bed equipment for the solar photocatalysis-membrane separation (E-SPME), comprising solar photocatalytic degradation and membrane separation zones, was first introduced, and the photocatalytic degradation of acid red B wastewater (ARBW) with a TiO2 photocatalyst was investigated using the E-SPME. The experimental results indicated the circulating flow of wastewater between the two zones and the increase in the ARBW photocatalytic degradation efficiency with decreasing membrane flux...
May 6, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28477350/protonation-state-coupled-conformational-dynamics-in-reaction-mechanisms-of-channel-and-pump-rhodopsins
#7
Ana-Nicoleta Bondar, Jeremy C Smith
Channel and pump rhodopsins use energy from light absorbed by a covalently bound retinal chromophore to transport ions across membranes of microbial cells. Ion transfer steps, including proton transfer, can couple to changes in protein conformational dynamics and water positions. Although general principles of how microbial rhodopsins function are largely understood, key issues pertaining to reaction mechanisms remain unclear. In this review, we compare the protonation-coupled dynamics of pump and channel rhodopsins, highlighting the roles that water dynamics, protein electrostatics, and protein flexibility can have in ion transport mechanisms...
May 6, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28477344/artocarpin-enriched-artocarpus-altilis-heartwood-extract-protects-against-uvb-induced-mechanical-damage-in-dermal-fibroblasts
#8
Narisara Tiraravesit, Philippe Humbert, Sophie Robin, Marion Tissot, Céline Viennet, Jarupa Viyoch
Ultraviolet B radiation has a negative effect on the mechanical properties of the dermis and on the activities of resident fibroblasts, including the disorganization and fragmentation of the dermal extracellular matrix (ECM). It induces alterations in cytoskeleton structure, motility and the contractile forces of the fibroblasts. The present study aimed to evaluate the protective effect of Artocarpus altilis heartwood extract on the mechanical properties of ultraviolet B-irradiated fibroblasts. Human skin fibroblasts were pretreated with 50 μg/mL artocarpin-enriched extract for 48 h and later irradiated with ultraviolet B at 200 mJ/cm(2) ...
May 6, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28477333/a-boron-2-2-pyridyl-imidazole-fluorescence-probe-for-bovine-serum-albumin-discrimination-over-other-proteins-and-identification-of-its-denaturation
#9
Chunlin Liu, Wei Yang, Jinya Du, Ping Shen, Changying Yang
Boron 2-(2'-pyridyl) imidazole complex (BOPIM) derivatives, BOPIM-1 and BOPIM-2, involving twisted intra-molecular charge transfer (TICT) characteristic, were investigated to probe bovine serum albumin (BSA). BOPIM-1 was demonstrated to be an efficient fluorescence probe to discriminate BSA from other proteins including human serum albumin (HSA). The encapsulation of BOPIM-1 in the hydrophobic subdomain IIA of BSA inhibited the TICT state and resulted in 70-fold emission enhancement of BOPIM-1. Besides, it was found that BOPIM-1 could distinguish denatured BSA from the native, due to the difference of 15 nm emission wavelength at least...
May 6, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28471503/the-use-of-directional-reflectance-measurement-for-in-vivo-assessment-of-protective-properties-of-cosmetics-in-the-infrared-radiation-range
#10
Sławomir Wilczyński, Anna Deda, Robert Koprowski, Anna Banyś, Barbara Błońska-Fajfrowska
Photoprotection of skin is now focused on UV radiation. The aim of this study was to evaluate in vivo cosmetic products in terms of protection against infrared radiation (IR) and propose a methodology for conducting such measurements. The directional reflectance (DR) of 12 UV filters, 6 care creams and 2 preparations containing fumed silica applied on the forearm of 36 volunteers was examined in six spectral bands for two angles of incidence. SOC-410 Directional Hemispherical Reflectometer was used to measure DR...
May 4, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28471473/spectral-remittance-and-transmittance-of-visible-and-of-infrared-a-radiation-in-human-skin-comparison-between-in-vivo-measurements-and-model-calculations
#11
Helmut Piazena, Hans Meffert, Ralf Uebelhack
To assess the inter-individual variability of spectral remittance and of spectral transmittance of visible and of infrared-A radiation interacting with human skin and subcutaneous tissue direct measurements were performed in vivo using healthy persons of different skin color types. Up to wavelengths of about 900 nm both spectral remittance and spectral transmittance depended significantly on the individual contents of melanin and of hemoglobin in the skin, whereas the contents of water and of lipids mainly determined spectral slopes of both characteristics of interaction for wavelengths above about 900 nm...
May 4, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28449224/validation-of-omi-uv-satellite-data-using-spectral-and-broadband-surface-based-measurements-at-a-queensland-site
#12
Mustapha A Jebar, Alfio V Parisi, Nathan J Downs, Joanna F Turner
This research reconstructed and validated the broadband UVA irradiances derived from discrete spectral irradiance data retrieved from the Ozone Monitoring Instrument (OMI) satellite from 1 January to 31 December 2009. OMI data at solar noon was compared to ground based spectral irradiances at Toowoomba (27°36' S 151°55' E), Australia at 310, 324 and 380 nm for both cloud free and all sky conditions. There was a strong relationship between the ground based UV spectroradiometer data and satellite based measurements with an R(2) of 0...
April 27, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28439932/photophysical-characterization-of-tolyporphin-a-a-naturally-occurring-dioxobacteriochlorin-and-synthetic-oxobacteriochlorin-analogues
#13
Don Hood, Dariusz M Niedzwiedzki, Ran Zhang, Yunlong Zhang, Jingqiu Dai, Eric S Miller, David F Bocian, Philip G Williams, Jonathan S Lindsey, Dewey Holten
Tolyporphins are tetrapyrrole macrocycles produced by a cyanobacterium-containing culture known as HT-58-2. Tolyporphins A-J are free base dioxobacteriochlorins whereas tolyporphin K is an oxochlorin. Here, the photophysical characterization is reported of tolyporphin A and two synthetic analogues, an oxobacteriochlorin and a dioxobacteriochlorin. The characterization (in toluene, diethyl ether, ethyl acetate, dichloromethane, 1-pentanol, 2-butanone, ethanol, methanol, N,N-dimethylformamide, and dimethylsulfoxide) includes static absorption and fluorescence spectra, fluorescence quantum yields, and time-resolved data...
April 25, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28436996/continuum-electrostatic-calculation-on-bovine-rhodopsin-protonation-and-the-effect-of-the-membrane-potential
#14
Elisa Bombarda, G Matthias Ullmann
In this work, we calculate the protonation probabilities of titratable residues of bovine rhodopsin using the Poisson-Boltzmann equation. We also consider the influence of the membrane potential. Our results indicate that at physiological pH, the titratable groups directly involved in photosensing, namely Glu113, Glu181 and the retinal Schiff base, are charged. In contrast, the residues Asp83, Glu122, and His211, which are buried in the membrane, are uncharged. However, since these later residues are localized in the middle of the membrane, they are exposed to the membrane potential more strongly, which may have important functional implications...
April 24, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28436037/high-level-ab-initio-absorption-spectra-simulations-of-neutral-anionic-and-neutral-chromophore-of-green-fluorescence-protein-chromophore-models-in-gas-phase-and-solution
#15
Ivelina Georgieva, Adelia J A Aquino, Natasha Trendafilova, Hans Lischka
Semi-classical ab initio simulations of the absorption spectra of neutral and anionic p-hydroxybenzylidene-2,3-dimethylimidazolinone (p-HBDI), a model chromophore of Green Fluorescent Protein (GFP) and of a positively charged neutral (N+)-HBDI chromophore model were performed in gas phase with the resolution-of-identity algebraic diagrammatic construction through second-order (RI-ADC(2)) method. The calculated absorption spectra in gas phase are composed of one band centered at 3.51 eV (HBDI), 2.50 eV (HBDI(-) ) and 3...
April 24, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28432821/addition-of-hydrogen-peroxide-to-groundwater-with-natural-iron-induces-water-disinfection-by-photo-fenton-at-circumneutral-ph-and-other-photochemical-events
#16
Héctor Mario Gutiérrez-Zapata, John Jairo Alvear-Daza, Julián Andrés Rengifo-Herrera, Janeth Sanabria
Samples of natural groundwater (with low turbidity, neutral pH and 0.3 mg L(-1) iron concentration) inoculated with Escherichia coli K-12, were exposed to simulated solar light both in the presence and absence 10 mg L(-1) of H2 O2. Results demonstrated that the viability of E. coli (by DVC-FISH) was grounded to zero after 360 min of irradiation. This abatement could be caused by the oxidative stress induced by •OH radicals or another photo-induced reactive oxygen species. Two 2(3) factorial experimental designs enabled the evaluation of the effects of chemical factors on the inactivation of E...
April 22, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28432795/validation-of-sun-exposure-reported-annually-against-interim-self-report-and-daily-sun-diaries
#17
Laura King, Fan Xiang, Ashwin Swaminathan, Keith Dear, Simone L Harrison, Ingrid van der Mei, Michael G Kimlin, Catherine D'Este, Robyn M Lucas
Data on personal sun exposure over a period exceeding the immediate past days or weeks is typically self-reported in brief questionnaire items. The validity of such self-reporting of longer-term personal sun exposure, e.g. over a year, including detail on variation across seasons, has not previously been investigated. In a volunteer sample (n = 331) of Australian adults age 18 years and over, we assessed the 12-month reliability of sun exposure reported separately for each season, and its accuracy compared to a daily sun diary in the same season...
April 22, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28425091/marine-bioluminescence-measurement-by-a-classical-light-sensor-and-related-foraging-behaviour-of-a-deep-diving-predator
#18
Jade Vacquié-Garcia, Jérôme Mallefet, Frédéric Bailleul, Baptiste Picard, Christophe Guinet
Bioluminescence is produced by a broad range of organisms for defense, predation or communication purposes. Southern elephant seal (SES) vision is adapted to low intensity light with a peak sensitivity, matching the wavelength emitted by myctophid species, one of the main prey of female SES. A total of 11 satellite-tracked female SES were equipped with a Time-Depth-Light 3D-accelerometers (TDR10-X) in order to assess whether bioluminescence could be used by SES to locate their prey. First, we demonstrated experimentally that the TDR10-X light sensor was sensitive enough to detect natural bioluminescence; however, we highlighted a low distance detection of the sensor...
April 20, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28391638/construction%C3%A2-of-er-3-yalo3-rgo-tio2-hybrid-electrode-with%C3%A2-enhanced%C3%A2-photoelectrocatalytic%C3%A2-performance%C3%A2-in-methylene%C3%A2-blue%C3%A2-degradation%C3%A2-under%C3%A2-visible%C3%A2-light
#19
Xian Zhou, Jun Zhang, Yue Ma, Hanqing Cheng, Shaozhu Fu, Dandan Zhou, Shuangshi Dong
Much attention has been paid on doping TiO2 to narrow its band gap to promote the absorption of visible light and restrain the recombination of electron-hole pairs to improve its efficiency in photoelectrocatalysis (PEC) under visible light irradiation. However, the oxidation potential energy of photo-induced holes for the modified catalysts by visible light excitation is lower than that without modification by UV excitation. In this work, we synthesized a co-coupled TiO2 electrode (denoted ERT) with the Er(3+) :YAlO3 and reduced graphene oxide (RGO), achieving the synergetic effect of visible-light-to-UV up conversion and response and great electron transfer ability...
April 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28391637/synthesis-photophysics-and-pdt-evaluation-of-mono-di-tri-and-hexa-peg-chlorins-for-pointsource-photodynamic-therapy
#20
Tobias Bornhütter, Ashwini A Ghogare, Annegret Preuß, Alexander Greer, Beate Röder
Pointsource photodynamic therapy (PSPDT) is a newly developed fiber optic method aimed at the delivery of photosensitizer, light and oxygen to a diseased site. Because of a need for developing photosensitizers with desirable properties for PSPDT, we have carried out a synthetic, photophysical and phototoxicity study on a series of PEGylated sensitizers. Chlorin and pheophorbide sensitizers were readily amenable to our synthetic PEGylation strategy to reach triPEG and hexaPEG galloyl pheophorbides and mono-, di-, triPEG chlorins...
April 9, 2017: Photochemistry and Photobiology
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