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Photochemistry and Photobiology

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https://www.readbyqxmd.com/read/28608526/clothing-protection-from-uvr-a-new-method-for-assessment
#1
Ryan Gage, William Leung, James Stanley, Anthony Reeder, Michelle Barr, Tim Chambers, Moira Smith, Louise Signal
Clothing modifies ultraviolet radiation exposure from the sun, and has an impact on skin cancer risk and the endogenous synthesis of vitamin D3 . There is no standardized method available for assessing body surface area covered by clothing, which limits generalizability between study findings. We calculated the body cover provided by 38 clothing items using diagrams of body surface area (BSA), adjusting the values to account for differences in BSA by age. Diagrams displaying each clothing item were developed and incorporated into a coverage assessment procedure (CAP)...
June 13, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28599356/an-in-vitro-model-for-fibroblast-photoaging-comparing-single-and-repeated-uva-irradiations
#2
Wongnapa Nakyai, Aurasorn Saraphanchotiwitthaya, Celine Viennet, Philippe Humbert, Jarupa Viyoch
The current method for efficient evaluation of anti-photoaging compounds is an in vitro skin culture model using a single ultraviolet A (UVA) irradiation of fibroblasts. However, skin photoaging is caused by repeated exposure to UVA radiation. The objective of this study was to develop an appropriate model for in vitro skin photoaging by comparing the different effects of single (5 J/cm(2) ) and repeated exposures (5 J/cm(2) x 3 times) of fibroblasts to UVA irradiation. Our results demonstrated that a single and repeated exposure to UVA irradiation had different effects on fibroblasts...
June 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28597944/a-quantum-mechanical-study-of-the-binding-pocket-of-proteorhodopsin-absorption-and-vibrational-spectra-modulated-by-analogue-chromophores
#3
Francesco Buda, Tom Keijer, Srividya Ganapathy, Willem J de Grip
Proteorhodopsin is a light-driven proton pumping membrane protein related to bacteriorhodopsin. It contains an all-trans retinal A1 chromophore covalently bound to a lysine residue via a protonated Schiff base. In this study, we exploited density functional theory (DFT) calculations to investigate the retinal binding pocket in the dark state and after mimicking photoisomerization. The model of the binding pocket is constructed incrementally by adding the residues near the retinal that are necessary to ensure a stable protonated Schiff base...
June 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28597924/special-issue-honoring-professor-hasan-mukhtar
#4
Nihal Ahmad
The purpose of this Special Issue is to honor Professor Hasan Mukhtar, whose contributions in the research areas of Photobiology, Photomedicine, Photocarcinogenesis and Chemoprevention are well-known. Dr. Mukhtar has been a teacher, mentor and colleague to me for the last 20 years. He is a researcher extraordinaire, a mentor par excellence and a true gentleman. This article is protected by copyright. All rights reserved.
June 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28574176/a-photosensitizer-lanthanide-nanoparticle-formulation-that-induces-singlet-oxygen-with-direct-light-excitation-but-not-by-photon-or-x-ray-energy-transfer
#5
Rima Chouikrat, Francis Baros, Jean-Claude André, Régis Vanderesse, Bruno Viana, Anne-Laure Bulin, Christophe Dujardin, Philippe Arnoux, Marc Verelst, Céline Frochot
We report the design and synthesis of europium-doped gadolinium oxysulfide nanoscintillators Gd2 O2 S:Eu(3+) conjugated with two different photosensitizers (PSs): a zinc chlorin (ZnTPC) and a zinc phtalocyanine (ZnPc) by covalent bonding through a layer of N-(3-trimethoxysilylpropyl)diethylenetriamine (TPDA). These conjugates were designed to be activated under X-ray excitation to allow a photodynamic effect, although this desired outcome was not achieved in this study. The monodispersed nanoparticles of ∼70 nm diameter were pegylated to be stabilized in aqueous suspension...
June 2, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28574149/measurement-of-uv-emission-from-a-diffusing-optical-fiber-using-radiochromic-film
#6
David Welch, Henry M Spotnitz, David J Brenner
Analysis of the emission pattern from optical diffuser tips is vital to their usage in biomedical applications, especially as they find growing functionality beyond established phototherapy techniques. The use of ultraviolet radiation with diffuser tips increases the need to accurately characterize these devices, both for effective application and to avoid potentially dangerous exposure conditions. This work presents a new method to capture the diffusion pattern at a high resolution through the use of radiochromic film...
June 2, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28543667/panchromatic-osmium-complexes-for-photodynamic-therapy-solutions-to-existing-problems-and-new-questions
#7
Edith C Glazer
This article is a highlight of the paper by Lazic et al. in this issue of Photochemistry and Photobiology. It describes the validation of osmium coordination complexes as photosensitizers for photodynamic therapy, with very promising in vivo results that demonstrate radical improvements in survival following irradiation with visible (635 nm) or near-IR (NIR; 808 nm) light. An unusual feature in the study is that the different complexes exhibit disparate photophysical and photobiological characteristics, despite sharing common structural motifs...
May 23, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28543444/mechanistic-studies-on-the-peroxyoxalate-chemiluminescence-using-sodium-salicylate-as-base-catalyst
#8
Glalci A Souza, André P Lang, Wilhelm J Baader
Mechanistic studies on the peroxyoxalate chemiluminescence are often conducted with imidazole as base and nucleophilic catalyst. However, it is also known that this compound, at high concentrations, leads to a drastic reduction of the chemiluminescence quantum yields, apparently due the destruction of the high-energy intermediate. Consequently, the search for new catalysts for this transformation is of importance for mechanistic studies as well as analytical application. Therefore, we report here a study on the mechanism of the peroxyoxalate reaction with sodium salicylate as base catalyst; which has already been utilized in this reaction, however, no detailed mechanistic investigation is known...
May 23, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28513845/claud-s-rupert-1919-2017-the-father-of-dna-repair
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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